@article {pmid38663447, year = {2024}, author = {Zhang, Z and Ma, J and Xu, T and Wang, T and Jia, X and Lin, J and Lv, C and Cao, L and Ying, Y and Ji, L and Wang, S and Fu, C}, title = {Transpiration-Inspired Fabric Dressing for Acceleration Healing of Wound Infected with Biofilm.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2401005}, doi = {10.1002/adhm.202401005}, pmid = {38663447}, issn = {2192-2659}, abstract = {In chronic wound management, efficacious handling of exudate and bacterial infections stands as a paramount challenge. Here we introduced a novel biomimetic fabric, inspired by the natural transpiration mechanisms in plants. Uniquely, the fabric combines a commercial polyethylene terephthalate (PET) fabric with asymmetrically grown 1D rutile titanium dioxide (TiO2) micro/nanostructures, emulating critical plant features: hierarchically porous networks and hydrophilic water conduction channels. This structure endows the fabric with exceptional antigravity wicking-evaporation performance, evidenced by a 780% one-way transport capability and a 0.75 g h[-1] water evaporation rate, which significantly surpasses that of conventional moisture-wicking textiles. Moreover, the incorporated 1D rutile TiO2 micro/nano-structures presented solar-light induced antibacterial activity, crucial for disrupting and eradicating wound biofilms. The biomimetic transpiration fabric has been employed to drain exudate and eradicate biofilms in Staphylococcus aureus (S. aureus)-infected wounds, demonstrating a much faster infection eradication capability compared to clinically common ciprofloxacin irrigation. These findings illuminate the path for developing high-performance, textile-based wound dressings, offering efficient clinical platforms to combat biofilms associated with chronic wounds. This article is protected by copyright. All rights reserved.}, } @article {pmid38661711, year = {2024}, author = {Souza, V and Polaquini, CR and de Moraes, GR and Oliveira Braga, AR and da Silva, PV and da Silva, DR and Ribeiro Lima, FR and Regasini, LO and Cássia Orlandi Sardi, J}, title = {Diacetylcurcumin: a novel strategy against Enterococcus faecalis biofilm in root canal disinfection.}, journal = {Future microbiology}, volume = {}, number = {}, pages = {}, doi = {10.2217/fmb-2023-0235}, pmid = {38661711}, issn = {1746-0921}, abstract = {Aim: We evaluated Diacetylcurcumin (DAC), a derivative of curcumin, for its antibacterial and antibiofilm properties against Enterococcus faecalis. Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration were determined, along with antibiofilm potential and toxicity in Galleria mellonella. Additionally, in silico computational analysis was performed to understand its mechanisms of action. Results & conclusion: DAC demonstrated significant antibacterial effects, with MIC and MBC values of 15.6 and 31.25 μg/ml, respectively, and reduced biofilm formation. A synergistic effect, reducing biofilm by 77%, was observed when combined with calcium hydroxide. G. mellonella toxicity tests confirmed DAC's safety at tested concentrations, suggesting its potential for use in root canal disinfection products.}, } @article {pmid38660899, year = {2024}, author = {Li, YY and Liu, HC and Wang, HP and DU, TY and Jiang, L}, title = {[Characteristics of drug resistance and biofilm formation in carbapenem-resistant Acinetobacter baumannii in hospitalized children].}, journal = {Zhongguo dang dai er ke za zhi = Chinese journal of contemporary pediatrics}, volume = {26}, number = {4}, pages = {358-364}, pmid = {38660899}, issn = {1008-8830}, mesh = {*Acinetobacter baumannii/drug effects/genetics ; *Biofilms/drug effects ; *Carbapenems/pharmacology ; Humans ; Child ; *Acinetobacter Infections/microbiology ; Child, Preschool ; beta-Lactamases/genetics ; Child, Hospitalized ; Drug Resistance, Bacterial/genetics ; Anti-Bacterial Agents/pharmacology ; Female ; Infant ; Male ; Microbial Sensitivity Tests ; Bacterial Proteins/genetics ; }, abstract = {OBJECTIVES: To study the distribution, drug resistance, and biofilm characteristics of carbapenem-resistant Acinetobacter baumannii (CRAB) isolated from hospitalized children, providing a reference for the prevention and treatment of CRAB infections in hospitalized children.

METHODS: Forty-eight CRAB strains isolated from January 2019 to December 2022 were classified into epidemic and sporadic strains using repetitive extragenic palindromic sequence-based polymerase chain reaction. The drug resistance, biofilm phenotypes, and gene carriage of these two types of strains were compared.

RESULTS: Both the 22 epidemic strains and the 26 sporadic strains were producers of Class D carbapenemases or extended-spectrum β-lactamases with downregulated outer membrane porins, harboring the VIM, OXA-23, and OXA-51 genes. The biofilm formation capability of the sporadic strains was stronger than that of the epidemic strains (P<0.05). Genes related to biofilm formation, including Bap, bfs, OmpA, CsuE, and intI1, were detected in both epidemic and sporadic strains, with a higher detection rate of the intI1 gene in epidemic strains (P<0.05).

CONCLUSIONS: CRAB strains are colonized in the hospital, with sporadic strains having a stronger ability to form biofilms, suggesting the potential for forming new clonal transmissions in the hospital. Continuous monitoring of the epidemic trends of CRAB and early warning of the distribution of epidemic strains are necessary to reduce the risk of CRAB infections in hospitalized children.}, } @article {pmid38659983, year = {2024}, author = {Alharbi, NK and Azeez, ZF and Alhussain, HM and Shahlol, AMA and Albureikan, MOI and Elsehrawy, MG and Aloraini, GS and El-Nablaway, M and Khatrawi, EM and Ghareeb, A}, title = {Tapping the biosynthetic potential of marine Bacillus licheniformis LHG166, a prolific sulphated exopolysaccharide producer: structural insights, bio-prospecting its antioxidant, antifungal, antibacterial and anti-biofilm potency as a novel anti-infective lead.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1385493}, pmid = {38659983}, issn = {1664-302X}, abstract = {The escalating global threat of antimicrobial resistance necessitates prospecting uncharted microbial biodiversity for novel therapeutic leads. This study mines the promising chemical richness of Bacillus licheniformis LHG166, a prolific exopolysaccharide (EPSR2-7.22 g/L). It comprised 5 different monosaccharides with 48.11% uronic acid, 17.40% sulfate groups, and 6.09% N-acetyl glucosamine residues. EPSR2 displayed potent antioxidant activity in DPPH and ABTS[+], TAC and FRAP assays. Of all the fungi tested, the yeast Candida albicans displayed the highest susceptibility and antibiofilm inhibition. The fungi Aspergillus niger and Penicillium glabrum showed moderate EPSR2 susceptibility. In contrast, the fungi Mucor circinelloides and Trichoderma harzianum were resistant. Among G+ve tested bacteria, Enterococcus faecalis was the most susceptible, while Salmonella typhi was the most sensitive to G-ve pathogens. Encouragingly, EPSR2 predominantly demonstrated bactericidal effects against both bacterial classes based on MBC/MIC of either 1 or 2 superior Gentamicin. At 75% of MBC, EPSR2 displayed the highest anti-biofilm activity of 88.30% against B. subtilis, while for G-ve antibiofilm inhibition, At 75% of MBC, EPSR2 displayed the highest anti-biofilm activity of 96.63% against Escherichia coli, Even at the lowest dose of 25% MBC, EPSR2 reduced biofilm formation by 84.13% in E. coli, 61.46% in B. subtilis. The microbial metabolite EPSR2 from Bacillus licheniformis LHG166 shows promise as an eco-friendly natural antibiotic alternative for treating infections and oxidative stress.}, } @article {pmid38659587, year = {2024}, author = {Chen, Q and Dong, Z and Yao, X and Sun, H and Pan, X and Liu, J and Huang, R}, title = {Bactericidal and biofilm eradication efficacy of a fluorinated benzimidazole derivative, TFBZ, against methicillin-resistant Staphylococcus aureus.}, journal = {Frontiers in pharmacology}, volume = {15}, number = {}, pages = {1342821}, pmid = {38659587}, issn = {1663-9812}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a major inducement of nosocomial infections and its biofilm formation render the high tolerance to conventional antibiotics, which highlights the requirement to develop new antimicrobial agents urgently. In this study, we identified a fluorinated benzimidazole derivative, TFBZ, with potent antibacterial efficacy toward planktonic MRSA (MIC = 4 μg/mL, MBC = 8 μg/mL) and its persistent biofilms (≥99%, MBEC = 8 μg/mL). TFBZ manifested significant irreversible time-dependent killing against MRSA as characterized by diminished cell viability, bacterial morphological change and protein leakage. Furthermore, the results from CBD devices, crystal violet assay in conjunction with live/dead staining and scanning electron microscopy confirmed that TFBZ was capable of eradicating preformed MRSA biofilms with high efficiency. Simultaneously, TFBZ reduced the bacterial invasiveness and exerted negligible hemolysis and cytotoxicity toward mammalian cells, which ensuring the robust therapeutic effect on mouse skin abscess model. The transcriptome profiling and quantitative RT-PCR revealed that a set of encoding genes associated with cell adhesion, biofilm formation, translation process, cell wall biosynthesis was consistently downregulated in MRSA biofilms upon exposure to TFBZ. In conclusion, TFBZ holds promise as a valuable candidate for therapeutic applications against MRSA chronic infections.}, } @article {pmid38658316, year = {2024}, author = {Cassola, F and Ramírez, N and Delarmelina, C and Duarte, MCT}, title = {In vitro determination of the susceptibility of Malassezia furfur biofilm to different commercially used antimicrobials.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13419}, pmid = {38658316}, issn = {1600-0463}, abstract = {Malassezia furfur is a yeast known as the etiological agent of seborrheic dermatitis. We evaluated the action of five different antimicrobials (amphotericin B, chloramphenicol, ketoconazole, fluconazole, and nystatin) on inhibiting biofilm formation and removing biofilm already formed by M. furfur. The assays were carried out using the microdilution method, and scanning electron microscopy images were used to analyze the biofilm structure. According to the results obtained, the percentage of inhibition was higher for chloramphenicol, followed by ketoconazole, nystatin, and amphotericin B. Regarding the eradication of the biofilm formed, the highest percentage was chloramphenicol, followed by ketoconazole and nystatin. Amphotericin B did not affect biofilm eradication, whereas fluconazole did not cause significant changes inhibiting or removing M. furfur biofilm. Therefore, except for fluconazole, all evaluated antimicrobials had inhibiting effects on the biofilm of M. furfur, either in its formation and/or eradication. Although the results achieved with chloramphenicol have been highlighted, further in vitro and in vivo studies are still needed in order to include this antimicrobial in the therapy of seborrheic dermatitis due to its toxicity, especially to the bone marrow.}, } @article {pmid38658078, year = {2024}, author = {Banerjee, A and Stockbridge, RB and Tenuta, LMA}, title = {Measurement and analysis of microbial fluoride resistance in dental biofilm models.}, journal = {Methods in enzymology}, volume = {696}, number = {}, pages = {155-174}, doi = {10.1016/bs.mie.2023.12.018}, pmid = {38658078}, issn = {1557-7988}, mesh = {*Biofilms/drug effects/growth & development ; *Streptococcus mutans/drug effects/genetics/physiology/metabolism/growth & development ; *Fluorides/pharmacology/metabolism ; *Candida albicans/drug effects/genetics/metabolism/physiology ; *Streptococcus gordonii/drug effects/genetics/physiology ; Humans ; Bacterial Proteins/genetics/metabolism ; Drug Resistance, Bacterial/genetics ; Dental Caries/microbiology ; }, abstract = {The interactions between communities of microorganisms inhabiting the dental biofilm is a major determinant of oral health. These biofilms are periodically exposed to high concentrations of fluoride, which is present in almost all oral healthcare products. The microbes resist fluoride through the action of membrane export proteins. This chapter describes the culture, growth and harvest conditions of model three-species dental biofilm comprised of cariogenic pathogens Streptococcus mutans and Candida albicans and the commensal bacterium Streptococcus gordonii. In order to examine the role of fluoride export by S. mutans in model biofilms, procedures for generating a strain of S. mutans with a genetic knockout of the fluoride exporter are described. We present a case study examining the effects of this mutant strain on the biofilm mass, acid production and mineral dissolution under exposure to low levels of fluoride. These general approaches can be applied to study the effects of any gene of interest in physiologically realistic multispecies oral biofilms.}, } @article {pmid38657691, year = {2024}, author = {Cerda, Á and Gonzalez, M and Rodríguez, C and González, H and Serrano, J and Leiva, E}, title = {Feammox bacterial biofilm formation in HFMB.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {142072}, doi = {10.1016/j.chemosphere.2024.142072}, pmid = {38657691}, issn = {1879-1298}, abstract = {Nitrogen pollution has been increasing with the development of industrialization. Consequently, the excessive deposition of reactive nitrogen in the environment has generated the loss of biodiversity and eutrophication of different ecosystems. In 2005, a Feammox process was discovered that anaerobically metabolizes ammonium. Feammox with the use of hollow fiber membrane bioreactors (HFMB), based on the formation of biofilms of bacterial communities, has emerged as a possible efficient and sustainable method for ammonium removal in environments with high iron concentrations. This work sought to study the possibility of implementing, at laboratory scale, an efficient method by evaluating the use of HFMB. Samples from an internal circulation reactor (IC) incubated in culture media for Feammox bacteria. The cultures were enriched in a batch reactor to evaluate growth conditions. Next, HFMB assembly was performed, and Feammox parameters were monitored. Also, conventional PCR and scanning electron microscopy (SEM) analysis were performed to characterize the bacterial communities associated with biofilm formation. The use of sodium acetate presented the best performance for Feammox activity. The HFMB operation showed an ammonium (NH4[+]) removal of 50%. SEM analysis of the fibers illustrated the formation of biofilm networks formed by bacteria, which were identified as Albidiferax ferrireducens, Geobacter spp, Ferrovum myxofaciens, Shewanella spp., and Anammox. Functional genes Archaea/Bacteria ammonia monooxygenase, nrxA, hzsB, nirS and nosZ were also identified. The implementation of HFMB Feammox could be used as a sustainable tool for the removal of ammonium from wastewater produced because of anthropogenic activities.}, } @article {pmid38656598, year = {2024}, author = {Hassan, RM and Yehia, H and El-Behairy, MF and El-Azzouny, AA and Aboul-Enein, MN}, title = {Design and synthesis of new quinazolinone derivatives: investigation of antimicrobial and biofilm inhibition effects.}, journal = {Molecular diversity}, volume = {}, number = {}, pages = {}, pmid = {38656598}, issn = {1573-501X}, abstract = {New quinazolin-4-ones 9-32 were synthesized in an attempt to overcome the life-threatening antibiotic resistance phenomenon. The antimicrobial screening revealed that compounds 9, 15, 16, 18, 19, 20 and 29 are the most broad spectrum antimicrobial agents in this study with safe profile on human cell lines. Additionally, compounds 19 and 20 inhibited biofilm formation in Pseudomonas aeruginosa, which is regulated by quorum sensing system, at sub-minimum inhibitory concentrations (sub-MICs) with IC50 values 3.55 and 6.86 µM, respectively. By assessing other pseudomonal virulence factors suppression, it was found that compound 20 decreased cell surface hydrophobicity compromising bacterial cells adhesion, while both compounds 19 and 20 curtailed the exopolysaccharide production which constitutes the major component of the matrix binding biofilm components together. Also, at sub-MICs Pseudomonas cells twitching motility was impeded by compounds 19 and 20, a trait which augments the cells pathogenicity and invasion potential. Molecular docking study was performed to further evaluate the binding mode of candidates 19 and 20 as inhibitors of P. aeruginosa quorum sensing transcriptional regulator PqsR. The achieved results demonstrate that both compounds bear promising potential for discovering new anti-biofilm and quorum quenching agents against Pseudomonas aeruginosa without triggering resistance mechanisms as the normal bacterial life cycle is not disturbed.}, } @article {pmid38656049, year = {2024}, author = {Poker, BC and Oliveira, VC and Macedo, AP and Gonçalves, M and Ramos, AP and Silva-Lovato, CH}, title = {Evaluation of surface roughness, wettability and adhesion of multispecies biofilm on 3D-printed resins for the base and teeth of complete dentures.}, journal = {Journal of applied oral science : revista FOB}, volume = {32}, number = {}, pages = {e20230326}, doi = {10.1590/1678-7757-2023-0326}, pmid = {38656049}, issn = {1678-7765}, mesh = {*Biofilms ; *Surface Properties ; *Printing, Three-Dimensional ; *Streptococcus mutans/physiology ; *Staphylococcus aureus/physiology ; *Candida albicans/physiology ; *Wettability ; *Microscopy, Electron, Scanning ; *Materials Testing ; *Denture Bases/microbiology ; *Microscopy, Confocal ; *Acrylic Resins/chemistry ; *Bacterial Adhesion ; Analysis of Variance ; Reproducibility of Results ; Denture, Complete/microbiology ; Reference Values ; Colony Count, Microbial ; Linear Models ; }, abstract = {OBJECTIVE: This study evaluated the surface roughness, wettability and adhesion of multispecies biofilms (Candida albicans, Staphylococcus aureus and Streptococcus mutans) on 3D-printed resins for complete denture bases and teeth compared to conventional resins (heat-polymerized acrylic resin; artificial pre-fabricated teeth).

METHODOLOGY: Circular specimens (n=39; 6.0 mm Ø × 2.0 mm) of each group were subjected to roughness (n=30), wettability (n=30) and biofilm adhesion (n=9) tests. Three roughness measurements were taken by laser confocal microscopy and a mean value was calculated. Wettability was evaluated by the contact angle of sessile drop method, considering the mean of the three evaluations per specimen. In parallel, microorganism adhesion to resin surfaces was evaluated using a multispecies biofilm model. Microbial load was evaluated by determining the number of Colony Forming Units (CFU/mL) and by scanning electron microscopy (SEM). Data were subjected to the Wald test in a generalized linear model with multiple comparisons and Bonferroni adjustment, as well as two-way ANOVA (α=5%).

RESULTS: The roughness of the conventional base resin (0.01±0.04) was lower than that of the conventional tooth (0.14±0.04) (p=0.023) and 3D-printed base (0.18±0.08) (p<0.001). For wettability, conventional resin (84.20±5.57) showed a higher contact angle than the 3D-printed resin (60.58±6.18) (p<0.001). Higher microbial loads of S. mutans (p=0.023) and S. aureus (p=0.010) were observed on the surface of the conventional resin (S. mutans: 5.48±1.55; S. aureus: 7.01±0.57) compared to the 3D-printed resin (S. mutans: 4.11±1.96; S. aureus: 6.42±0.78). The adhesion of C. albicans was not affected by surface characteristics. The conventional base resin showed less roughness than the conventional dental resin and the printed base resin.

CONCLUSION: The 3D-printed resins for base and tooth showed less hydrophobicity and less adhesion of S. mutans and S. aureus than conventional resins.}, } @article {pmid38655044, year = {2024}, author = {Ahrari, F and Nazifi, M and Mazhari, F and Ghazvini, K and Menbari, S and Fekrazad, R and Babaei, K and Banihashemrad, A}, title = {Photoinactivation Effects of Curcumin, Nano-curcumin, and Erythrosine on Planktonic and Biofilm Cultures of Streptococcus mutans.}, journal = {Journal of lasers in medical sciences}, volume = {15}, number = {}, pages = {e7}, pmid = {38655044}, issn = {2008-9783}, abstract = {Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nano-curcumin, and erythrosine on the viability of Streptococcus mutans (S. mutans) in suspension and biofilm forms. Methods: Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 μM/L, 250 μM/L) were examined for their impact on planktonic and biofilm cultures of S. mutans, either individually or in conjunction with light irradiation (photodynamic therapy or PDT). A blue light-emitting diode (LED) with a central wavelength of 450 nm served as the light source. The results were compared to 0.12% chlorhexidine digluconate (CHX) as the positive control, and a solution containing neither a photosensitizer (PS) nor a light source as the negative control group. The dependent variable was the number of viable microorganisms per experiment (CFU/mL). Results: Antimicrobial PDT caused a significant reduction in the viability of S. mutans in both planktonic and biofilm forms, compared to the negative control group (P<0.05). The highest cell killing was observed in PDT groups with curcumin 3 g/L or erythrosine 250 μmol/L, although the difference with PDT groups using curcumin 1.5 g/L or erythrosine 100 μmol/L was not significant (P>0.05). Antimicrobial treatments were more effective against planktonic S. mutans than the biofilm form. Conclusion: PDT with either curcumin 1.5 g/L or erythrosine 100 μmol/L may be suggested as an alternative to CHX to inactivate the bacteria in dental plaque or deep cavities. Nano-curcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.}, } @article {pmid38654614, year = {2024}, author = {Li, Z and Lu, S and Liu, W and Chen, Z and Huang, Y and Li, X and Gong, J and Chen, X}, title = {Customized Lanthanide Nanobiohybrids for Noninvasive Precise Phototheranostics of Pulmonary Biofilm Infection.}, journal = {ACS nano}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsnano.4c00777}, pmid = {38654614}, issn = {1936-086X}, abstract = {A noninvasive strategy for in situ diagnosis and precise treatment of bacterial biofilm infections is highly anticipated but still a great challenge. Currently, no in vivo biofilm-targeted theranostic agent is available. Herein, we fabricated intelligent theranostic alginate lyase (Aly)-NaNdF4 nanohybrids with a 220 nm sunflower-like structure (NaNdF4@DMS-Aly) through an enrichment-encapsulating strategy, which exhibited excellent photothermal conversion efficiency and the second near-infrared (NIR-II) luminescence. Benefiting from the site-specific targeting and biofilm-responsive Aly release from NaNdF4@DMS-Aly, we not only enabled noninvasive diagnosis but also realized Aly-photothermal synergistic therapy and real-time evaluation of therapeutic effect in mice models with Pseudomonas aeruginosa biofilm-induced pulmonary infection. Furthermore, such nanobiohybrids with a sheddable siliceous shell are capable of delaying the NaNdF4 dissolution and biodegradation upon accomplishing the therapy, which is highly beneficial for the biosafety of theranostic agents.}, } @article {pmid38652947, year = {2024}, author = {Pokhrel, D and Thames, HT and Fugate, H and Dinh, T and Schilling, W and White, S and Ramachandran, R and Sukumaran, AT and Zhang, L}, title = {Increase in temperature facilitates Campylobacter jejuni biofilm formation under both aerobic and microaerobic incubation.}, journal = {Poultry science}, volume = {103}, number = {6}, pages = {103753}, doi = {10.1016/j.psj.2024.103753}, pmid = {38652947}, issn = {1525-3171}, abstract = {The formation of Campylobacter jeuni biofilms on processing surfaces is a significant concern in poultry processing, contributing to food safety risks. This study focused on assessing the biofilm forming capabilities of 12 field isolates of C. jejuni of different aerotolerance categories on stainless steel surfaces, a prevalent material in poultry processing environments. Working cultures of each isolate were prepared to approximately 6 log CFU/mL and incubated on stainless steel coupons under microaerobic or aerobic conditions at room temperature or 42°C for 72 h. Biofilm attached cells were enumerated using direct plating and biofilm density was measured using a crystal violet assay by measuring the optical density (OD600) a. Data analysis was conducted using the PROC GLIMMIX procedure in SAS 9.4 with a significance level of 0.05. The study revealed a notable interaction between aerotolerance categories and temperature (P < 0.039) impacting the number of biofilms attached C. jejuni cells on stainless steel coupons. All isolates had significantly higher counts when incubated at 42°C compared to room temperature, regardless of oxygen level (P < 0.001). Furthermore, stronger biofilm density was observed at 42°C compared to room temperature, regardless of oxygen level. These findings underscore the influence of temperature on the biofilm forming ability of C. jejuni. The ability of these field isolates to form biofilms under various environmental conditions suggests a heightened potential for surface colonization and increased infection risk in poultry processing facilities.}, } @article {pmid38652228, year = {2024}, author = {Cao, CY and Hou, ZJ and Ding, MZ and Gao, GR and Qiao, B and Wei, SY and Cheng, JS}, title = {Integrated Biofilm Modification and Transcriptional Analysis for Improving Fengycin Production in Bacillus amyloliquefaciens.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {38652228}, issn = {1867-1314}, support = {2018YFA0902200//National Key R&D Program of China/ ; 2018YFA0902200//National Key R&D Program of China/ ; 2018YFA0902200//National Key R&D Program of China/ ; 21878224//National Natural Science Foundation of China/ ; }, abstract = {Although fengycin exhibits broad-spectrum antifungal properties, its application is hindered due to its low biosynthesis level and the co-existence of iturin A and surfactin in Bacillus amyloliquefaciens HM618, a probiotic strain. In this study, transcriptome analysis and gene editing were used to explore the potential mechanisms regulating fengycin production in B. amyloliquefaciens. The fengycin level of B. amyloliquefacien HM-3 (∆itu-ΔsrfAA) was 88.41 mg/L after simultaneously inhibiting the biosyntheses of iturin A and surfactin. The knockout of gene eps associated with biofilm formation significantly increased the fengycin level of the strain HM618, whereas the fengycin level decreased 32.05% after knocking out sinI, a regulator of biofilm formation. Transcriptome analysis revealed that the differentially expressed genes, involved in pathways of amino acid and fatty acid syntheses, were significantly down-regulated in the recombinant strains, which is likely associated with a decrease of fengycin production. The knockout of gene comQXPA and subsequent transcriptome analysis revealed that the ComQXPA quorum sensing system played a positive regulatory role in fengycin production. Through targeted genetic modifications and fermentation optimization, the fengycin production of the engineered strain HM-12 (∆itu-ΔsrfAA-ΔyvbJ) in a 5-L fermenter reached 1.172 g/L, a 12.26-fold increase compared to the fengycin level in the strain HM-3 (∆itu-ΔsrfAA) in the Erlenmeyer flask. Taken together, these results reveal the underlying metabolic mechanisms associated with fengycin synthesis and provide a potential strategy for improving fengycin production in B. amyloliquefaciens.}, } @article {pmid38652445, year = {2022}, author = {Heredia, MY and Andes, D}, title = {Correction to: Production and Isolation of the Candida Species Biofilm Extracellular Matrix.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2542}, number = {}, pages = {C1}, doi = {10.1007/978-1-0716-2549-1_26}, pmid = {38652445}, issn = {1940-6029}, } @article {pmid38651875, year = {2024}, author = {Park, K-H and Kim, D and Jung, M and Kim, DY and Lee, Y-M and Lee, MS and Hong, K-W and Bae, I-G and Hong, SI and Cho, O-H}, title = {Effects of sub-inhibitory concentrations of nafcillin, vancomycibipn, ciprofloxacin, and rifampin on biofilm formation of clinical methicillin-resistant Staphylococcus aureus.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0341223}, doi = {10.1128/spectrum.03412-23}, pmid = {38651875}, issn = {2165-0497}, abstract = {UNLABELLED: Methicillin-resistant Staphylococcus aureus (MRSA) infections are often difficult to treat because of their biofilm-forming ability and antimicrobial resistance. We investigated the effects of sub-minimal inhibitory concentrations (MICs) of antibiotics on MRSA biofilm formation. Clinical MRSA isolates were grown with sub-MICs (1/256-1/2 × MICs) of nafcillin, vancomycin, ciprofloxacin, and rifampin. The biofilm biomass was measured using crystal violet staining. Of the 107 MRSA isolates tested, 63 (58.9%) belonged to sequence type 5 (ST5), and 44 (41.1%) belonged to ST72. The MIC50/MIC90 values of nafcillin, vancomycin, ciprofloxacin, and rifampin were 256/512, 1/2, 64/512, and 0.008/0.03 mg/L, respectively. The sub-MICs of nafcillin, vancomycin, ciprofloxacin, and rifampin promoted biofilm formation in 75 (70.1%), 49 (45.8%), 89 (83.2%), and 89 (83.2%) isolates, respectively. At sub-MICs of nafcillin, the factors associated with strong biofilm induction were the ST5 strain (P = 0.001) and agr dysfunction (P = 0.005). For the sub-MICs of ciprofloxacin, the associated factors were the ST5 strain (P = 0.002), staphylococcal protein A type t002 strain (P < 0.001), and ciprofloxacin resistance (P < 0.001). Among the sub-MICs of rifampin, only ST5 was associated with strong biofilm induction (P = 0.006). Because the sub-MICs of rifampin were much lower than clinically relevant concentrations, we further tested the capability of biofilm induction in 0.03[Formula: see text]32 mg/L of rifampin. At these concentrations, rifampin-induced biofilm formation was rare in rifampin-susceptible MRSA [1.0% (1 of 100)] but common in rifampin-resistant MRSA [71.4% (5 of 7), P < 0.001]. Induction of biofilm biomass at sub-MICs of antibiotics is common in clinical MRSA isolates and is differentially affected by the MRSA strain and antibiotic class.

IMPORTANCE: Bacteria can be exposed to sub-MICs of antibiotics at the beginning and end of a dosing regimen, between doses, or during low-dose therapies. Growing evidence suggests that sub-MICs of antimicrobials can stimulate MRSA biofilm formation and alter the composition of the biofilm matrix. Pevious studies have found that sub-MICs of oxacillin, methicillin, and amoxicillin promote biofilm formation in some community-acquired MRSA (CA-MRSA). We evaluated biofilm induction by sub-MICs of four different classes of antibiotics in 44 CA-MRSA and 63 healthcare-associated MRSA (HA-MRSA) strains. Our study indicated that sub-MICs of nafcillin, vancomycin, ciprofloxacin, and rifampin frequently promote biofilm induction in clinical MRSA isolates. Strong biofilm induction in sub-MICs of nafcillin, ciprofloxacin, and rifampin was more frequent in HA-MRSA than in CA-MRSA. Antibiotic-induced biofilm formation depends on the antibiotic class, MRSA strain, and antibiotic resistance. Our results emphasize the importance of maintaining effective bactericidal concentrations of antibiotics to treat biofilm-related infections.}, } @article {pmid38651823, year = {2024}, author = {Galvez-Llompart, M and Hierrezuelo, J and Blasco, M and Zanni, R and Galvez, J and de Vicente, A and Pérez-García, A and Romero, D}, title = {Targeting bacterial growth in biofilm conditions: rational design of novel inhibitors to mitigate clinical and food contamination using QSAR.}, journal = {Journal of enzyme inhibition and medicinal chemistry}, volume = {39}, number = {1}, pages = {2330907}, doi = {10.1080/14756366.2024.2330907}, pmid = {38651823}, issn = {1475-6374}, abstract = {Antimicrobial resistance (AMR) is a pressing global issue exacerbated by the abuse of antibiotics and the formation of bacterial biofilms, which cause up to 80% of human bacterial infections. This study presents a computational strategy to address AMR by developing three novel quantitative structure-activity relationship (QSAR) models based on molecular topology to identify potential anti-biofilm and antibacterial agents. The models aim to determine the chemo-topological pattern of Gram (+) antibacterial, Gram (-) antibacterial, and biofilm formation inhibition activity. The models were applied to the virtual screening of a commercial chemical database, resulting in the selection of 58 compounds. Subsequent in vitro assays showed that three of these compounds exhibited the most promising antibacterial activity, with potential applications in enhancing food and medical device safety.}, } @article {pmid38650753, year = {2024}, author = {Wen, Z and Chen, Y and Liu, T and Han, J and Jiang, Y and Zhang, K}, title = {Predicting Antibiotic Tolerance in hvKP and cKP Respiratory Infections Through Biofilm Formation Analysis and Its Resistance Implications.}, journal = {Infection and drug resistance}, volume = {17}, number = {}, pages = {1529-1537}, pmid = {38650753}, issn = {1178-6973}, abstract = {INTRODUCTION: Respiratory infections are a major global health concern, with Klebsiella pneumoniae standing out due to its evolving antibiotic resistance. This study compares the resistance profiles of hypervirulent Klebsiella pneumoniae (hvKP) and classical Klebsiella pneumoniae (cKP), aiming to shed light on their clinical implications.

METHODS: We analyzed 86 cases, comprising 42 hvKP and 44 cKP strains, using comprehensive antimicrobial susceptibility testing and clinical data evaluation to assess antibiotic tolerance and resistance mechanisms.

RESULTS: Our findings reveal distinct resistance patterns between hvKP and cKP, highlighting the role of chromosomal mutations and plasmid-mediated gene transfer in conferring antibiotic resistance. Notably, hvKP strains exhibited unique resistance trends, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, differing from those of cKP.

DISCUSSION: This research underscores the importance of continuous surveillance and the development of targeted therapies against antibiotic-resistant Klebsiella pneumoniae. It emphasizes the critical need for judicious antibiotic use and novel therapeutic approaches to combat respiratory infections caused by these increasingly resistant pathogens.}, } @article {pmid38650397, year = {2024}, author = {Kovács, F and Balla, N and Bozó, A and Harmath, A and Jakab, Á and Tóth, Z and Nagy, F and Majoros, L and Kovács, R}, title = {Epidemiology, clinical characteristics, outcome and biofilm forming properties in candidaemia: A single-centre retrospective 4-year analysis from Hungary.}, journal = {Mycoses}, volume = {67}, number = {4}, pages = {e13727}, doi = {10.1111/myc.13727}, pmid = {38650397}, issn = {1439-0507}, support = {UNKP-23-5-DE-480//New National Excellence Program of the Ministry for Innovation and Technology from the Source of the National Research, Development and Innovation Fund/ ; NKFIH FK138462//Hungarian National Research, Development and Innovation Office/ ; BO/00127/21/8//Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences/ ; }, abstract = {BACKGROUND: Candidaemia is a life-threatening disease that is associated with high mortality, especially in intensive care units (ICUs). The number of comprehensive studies dealing with the epidemiologic characteristics of biofilm-related properties is limited.

OBJECTIVE: This study evaluated the clinical characteristics of candidaemia, to assess the biofilm-forming properties of isolates, and to identify the risk factors of mortality.

PATIENTS AND METHODS: A total of 149 candidaemia episodes from the University of Debrecen, Clinical Centre, between January 2020 and December 2023 were investigated retrospectively. The susceptibility of Candida isolates to fluconazole, amphotericin B, anidulafungin, caspofungin, and micafungin was evaluated and compared to the susceptibility of 1-day-old biofilms. Multivariate logistic regression analysis was applied to identify the independent predictors of 30-day mortality rate.

RESULTS: The most common Candida species was Candida albicans (41%), followed by C. parapsilosis (20%), C. glabrata (14%), C. tropicalis (13%), rare Candida species (7%), and C. krusei (5%). Sixty-six percent of Candida isolates were biofilm formers and 44% had high metabolic activity. The 30-day mortality rate was 52%, which was higher in ICUs (65%). The logistic regression analysis revealed several factors significantly influencing mortality including ICU admission (odds ratio [OR] 2.99, 95% confidence interval [CI] 1.17-8.04, p = 0.025), fluconazole treatment (OR 4.12, 95% CI 1.62-11.42, p = .004), and pneumonia (OR 0.261, 95% CI 0.1-0.67, p = .006).

CONCLUSIONS: This comprehensive analysis supports the better characterisation of candidaemia in healthcare settings, which ultimately may reduce mortality among patients.}, } @article {pmid38649897, year = {2024}, author = {Chan, YL and Chee, CF and Tang, SN and Tay, ST}, title = {Unveilling genetic profiles and correlations of biofilm-associated genes, quorum sensing, and antibiotic resistance in Staphylococcus aureus isolated from a Malaysian Teaching Hospital.}, journal = {European journal of medical research}, volume = {29}, number = {1}, pages = {246}, pmid = {38649897}, issn = {2047-783X}, support = {IIRG003C-19FNW//Impact Oriented Interdisciplinary Grant/ ; }, abstract = {BACKGROUND: Staphylococcus aureus is a notorious multidrug resistant pathogen prevalent in healthcare facilities worldwide. Unveiling the mechanisms underlying biofilm formation, quorum sensing and antibiotic resistance can help in developing more effective therapy for S. aureus infection. There is a scarcity of literature addressing the genetic profiles and correlations of biofilm-associated genes, quorum sensing, and antibiotic resistance among S. aureus isolates from Malaysia.

METHODS: Biofilm and slime production of 68 methicillin-susceptible S. aureus (MSSA) and 54 methicillin-resistant (MRSA) isolates were determined using a a plate-based crystal violet assay and Congo Red agar method, respectively. The minimum inhibitory concentration values against 14 antibiotics were determined using VITEK® AST-GP67 cards and interpreted according to CLSI-M100 guidelines. Genetic profiling of 11 S. aureus biofilm-associated genes and agr/sar quorum sensing genes was performed using single or multiplex polymerase chain reaction (PCR) assays.

RESULTS: In this study, 75.9% (n = 41) of MRSA and 83.8% (n = 57) of MSSA isolates showed strong biofilm-forming capabilities. Intermediate slime production was detected in approximately 70% of the isolates. Compared to MSSA, significantly higher resistance of clindamycin, erythromycin, and fluoroquinolones was noted among the MRSA isolates. The presence of intracellular adhesion A (icaA) gene was detected in all S. aureus isolates. All MSSA isolates harbored the laminin-binding protein (eno) gene, while all MRSA isolates harbored intracellular adhesion D (icaD), clumping factors A and B (clfA and clfB) genes. The presence of agrI and elastin-binding protein (ebpS) genes was significantly associated with biofilm production in MSSA and MRSA isolates, respectively. In addition, agrI gene was also significantly correlated with oxacillin, cefoxitin, and fluoroquinolone resistance.

CONCLUSIONS: The high prevalence of biofilm and slime production among MSSA and MRSA isolates correlates well with the detection of a high prevalence of biofilm-associated genes and agr quorum sensing system. A significant association of agrI gene was found with cefoxitin, oxacillin, and fluoroquinolone resistance. A more focused approach targeting biofilm-associated and quorum sensing genes is important in developing new surveillance and treatment strategies against S. aureus biofilm infection.}, } @article {pmid38649100, year = {2024}, author = {Gulati, M and Thomas, JM and Ennis, CL and Hernday, AD and Rawat, M and Nobile, CJ}, title = {The bacillithiol pathway is required for biofilm formation in Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106657}, doi = {10.1016/j.micpath.2024.106657}, pmid = {38649100}, issn = {1096-1208}, abstract = {Staphylococcus aureus is a major human pathogen that can cause infections that range from superficial skin and mucosal infections to life threatening disseminated infections. S. aureus can attach to medical devices and host tissues and form biofilms that allow the bacteria to evade the host immune system and provide protection from antimicrobial agents. To counter host-generated oxidative and nitrosative stress mechanisms that are part of the normal host responses to invading pathogens, S. aureus utilizes low molecular weight (LMW) thiols, such as bacillithiol (BSH). Additionally, S. aureus synthesizes its own nitric oxide (NO), which combined with its downstream metabolites may also protect the bacteria against specific host responses. We have previously shown that LMW thiols are required for biofilm formation in Mycobacterium smegmatis and Pseudomonas aeruginosa. Here, we show that the S. aureus bshC mutant strain, which is defective in the last step of the BSH pathway and lacks BSH, is impaired in biofilm formation. We also identify a possible S-nitrosobacillithiol reductase (BSNOR), similar in sequence to an S-nitrosomycothiol reductase found in M. smegmatis and show that the putative S. aureus bsnoR mutant strain has reduced levels of BSH and decreased biofilm formation. Our studies also show that NO plays an important role in biofilm formation and that acidified sodium nitrite severely reduces biofilm thickness. These studies provide insight into the roles of oxidative and nitrosative stress mechanisms on biofilm formation and indicate that BSH and NO are key players in normal biofilm formation in S. aureus.}, } @article {pmid38647810, year = {2024}, author = {Zhang, CL and Wang, C and Dong, YS and Sun, YQ and Xiu, ZL}, title = {Dynamic immobilization of bacterial cells on biofilm in a polyester nonwoven chemostat.}, journal = {Bioresources and bioprocessing}, volume = {11}, number = {1}, pages = {17}, pmid = {38647810}, issn = {2197-4365}, support = {No. 2022YFA0911802//National Key R&D Program of China/ ; 2022YFA0911804//National Key R&D Program of China/ ; }, abstract = {Cell immobilization plays an important role in biocatalysis for high-value products. It is necessary to maintain the viability of immobilized cells for bioconversion using viable cells as biocatalysts. In this study, a novel polyester nonwoven chemostat was designed for cell immobilization to investigate biofilm formation and the dynamic balance between adsorption and desorption of cells on polyester nonwoven. The polyester nonwoven was suitable for cell immobilization, and the cell numbers on the polyester nonwoven can reach 6.5 ± 0.38 log CFU/mL. After adding the polyester nonwoven to the chemostat, the fluctuation phenomenon of free bacterial cells occurred. The reason for this phenomenon was the balance between adsorption and desorption of bacterial cells on the polyester nonwoven. Bacterial cells could adhere to the surface of polyester nonwoven via secreting extracellular polymeric substances (EPS) to form biofilms. As the maturation of biofilms, some dead cells inside the biofilms can cause the detachment of biofilms. This process of continuous adsorption and desorption of cells can ensure that the polyester nonwoven chemostat has lasting biological activity.}, } @article {pmid38647288, year = {2024}, author = {Waegenaar, F and García-Timermans, C and Van Landuyt, J and De Gusseme, B and Boon, N}, title = {Impact of operational conditions on drinking water biofilm dynamics and coliform invasion potential.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0004224}, doi = {10.1128/aem.00042-24}, pmid = {38647288}, issn = {1098-5336}, abstract = {UNLABELLED: Biofilms within drinking water distribution systems serve as a habitat for drinking water microorganisms. However, biofilms can negatively impact drinking water quality by causing water discoloration and deterioration and can be a reservoir for unwanted microorganisms. In this study, we investigated whether indicator organisms for drinking water quality, such as coliforms, can settle in mature drinking water biofilms. Therefore, a biofilm monitor consisting of glass rings was used to grow and sample drinking water biofilms. Two mature drinking water biofilms were characterized by flow cytometry, ATP measurements, confocal laser scanning microscopy, and 16S rRNA sequencing. Biofilms developed under treated chlorinated surface water supply exhibited lower cell densities in comparison with biofilms resulting from treated groundwater. Overall, the phenotypic as well as the genotypic characteristics were significantly different between both biofilms. In addition, the response of the biofilm microbiome and possible biofilm detachment after minor water quality changes were investigated. Limited changes in pH and free chlorine addition, to simulate operational changes that are relevant for practice, were evaluated. It was shown that both biofilms remained resilient. Finally, mature biofilms were prone to invasion of the coliform, Serratia fonticola. After spiking low concentrations (i.e., ±100 cells/100 mL) of the coliform to the corresponding bulk water samples, the coliforms were able to attach and get established within the mature biofilms. These outcomes emphasize the need for continued research on biofilm detachment and its implications for water contamination in distribution networks.

IMPORTANCE: The revelation that even low concentrations of coliforms can infiltrate into mature drinking water biofilms highlights a potential public health concern. Nowadays, the measurement of coliform bacteria is used as an indicator for fecal contamination and to control the effectiveness of disinfection processes and the cleanliness and integrity of distribution systems. In Flanders (Belgium), 533 out of 18,840 measurements exceeded the established norm for the coliform indicator parameter in 2021; however, the source of microbial contamination is mostly unknown. Here, we showed that mature biofilms, are susceptible to invasion of Serratia fonticola. These findings emphasize the importance of understanding and managing biofilms in drinking water distribution systems, not only for their potential to influence water quality, but also for their role in harboring and potentially disseminating pathogens. Further research into biofilm detachment, long-term responses to operational changes, and pathogen persistence within biofilms is crucial to inform strategies for safeguarding drinking water quality.}, } @article {pmid38647577, year = {2022}, author = {Wang, D and Unsal, T and Kumseranee, S and Punpruk, S and Saleh, MA and Alotaibi, MD and Xu, D and Gu, T}, title = {Mitigation of carbon steel biocorrosion using a green biocide enhanced by a nature-mimicking anti-biofilm peptide in a flow loop.}, journal = {Bioresources and bioprocessing}, volume = {9}, number = {1}, pages = {67}, pmid = {38647577}, issn = {2197-4365}, abstract = {Biocorrosion, also called microbiologically influenced corrosion (MIC), is a common operational threat to many industrial processes. It threatens carbon steel, stainless steel and many other metals. In the bioprocessing industry, reactor vessels in biomass processing and bioleaching are prone to MIC. MIC is caused by biofilms. The formation and morphology of biofilms can be impacted by fluid flow. Fluid velocity affects biocide distribution and MIC. Thus, assessing the efficacy of a biocide for the mitigation of MIC under flow condition is desired before a field trial. In this work, a benchtop closed flow loop bioreactor design was used to investigate the biocide mitigation of MIC of C1018 carbon steel at 25 °C for 7 days using enriched artificial seawater. An oilfield biofilm consortium was analyzed using metagenomics. The biofilm consortium was grown anaerobically in the flow loop which had a holding vessel for the culture medium and a chamber to hold C1018 carbon steel coupons. Peptide A (codename) was a chemically synthesized cyclic 14-mer (cys-ser-val-pro-tyr-asp-tyr-asn-trp-tyr-ser-asn-trp-cys) with its core 12-mer sequence originated from a biofilm dispersing protein secreted by a sea anemone which possesses a biofilm-free exterior. It was used as a biocide enhancer. The combination of 50 ppm (w/w) THPS (tetrakis hydroxymethyl phosphonium sulfate) biocide + 100 nM (180 ppb by mass) Peptide A resulted in extra 1-log reduction in the sulfate reducing bacteria (SRB) sessile cell count and the acid producing bacteria (APB) sessile cell count compared to 50 ppm THPS alone treatment. Furthermore, with the enhancement of 100 nM Peptide A, extra 44% reduction in weight loss and 36% abatement in corrosion pit depth were achieved compared to 50 ppm THPS alone treatment.}, } @article {pmid38650289, year = {2021}, author = {Ding, Q and Liu, Y and Hu, G and Guo, L and Gao, C and Chen, X and Chen, W and Chen, J and Liu, L}, title = {Engineering Escherichia coli biofilm to increase contact surface for shikimate and L-malate production.}, journal = {Bioresources and bioprocessing}, volume = {8}, number = {1}, pages = {118}, pmid = {38650289}, issn = {2197-4365}, support = {2020YFA0908300//National Key R & D Program of China/ ; 32021005//Science Fund for Creative Research Groups of the National Natural Science Foundation of China/ ; BK20211529//Provincal Outstanding Youth Foundation of Jiangsu Province/ ; 21978113//the National Natural Science Foundation of China/ ; 22008087//the National Natural Science Foundation of China/ ; 22108099//National Natural Science Foundation of China/ ; }, abstract = {Microbial organelles are a promising model to promote cellular functions for the production of high-value chemicals. However, the concentrations of enzymes and nanoparticles are limited by the contact surface in single Escherichia coli cells. Herein, the definition of contact surface is to improve the amylase and CdS nanoparticles concentration for enhancing the substrate starch and cofactor NADH utilization. In this study, two biofilm-based strategies were developed to improve the contact surface for the production of shikimate and L-malate. First, the contact surface of E. coli was improved by amylase self-assembly with a blue light-inducible biofilm-based SpyTag/SpyCatcher system. This system increased the glucose concentration by 20.7% and the starch-based shikimate titer to 50.96 g L[-1], which showed the highest titer with starch as substrate. Then, the contact surface of E. coli was improved using a biofilm-based CdS-biohybrid system by light-driven system, which improved the NADH concentration by 83.3% and increased the NADH-dependent L-malate titer to 45.93 g L[-1]. Thus, the biofilm-based strategies can regulate cellular functions to increase the efficiency of microbial cell factories based on the optogenetics, light-driven, and metabolic engineering.}, } @article {pmid38650271, year = {2021}, author = {Atnafu, T and Leta, S}, title = {A novel fragmented anode biofilm microbial fuel cell (FAB-MFC) integrated system for domestic wastewater treatment and bioelectricity generation.}, journal = {Bioresources and bioprocessing}, volume = {8}, number = {1}, pages = {112}, pmid = {38650271}, issn = {2197-4365}, abstract = {BACKGROUND: The critical MFC design challenge is to increase anode surface area. A novel FAB-MFC integrated system was developed and evaluated for domestic wastewater treatment. It was operated in fed-batch flow mode at 1-3 days of HRT with 755 mg/L CODIN and 0.76 kg-COD/m[3]/day. The study includes anaerobic-MFC and aerobic-MFC integrated systems. Microbial electrode jacket dish (MEJ-dish) with hybrid dimension (HD) was invented, first time to authors' knowledge, to boost anode biofilm growth. The treatment system with MEJ+ (FAB) and MEJ- (MFC) anode are called FAB-MFC and MFC, respectively.

RESULTS: Fragmented variable anode biofilm thickness was observed in FAB than MFC. The FAB-MFC (FAB+) simple technique increases the anode biofilm thickness by ~ 5 times MFC. Due to HD the anode biofilm was fragmented in FAB+ system than MFC. At the end of each treatment cycle, voltage drops. All FAB+ integrated systems reduced voltage drop relative to MFC. FAB reduces voltage drops better than MFC in anaerobic-MFC from 6 to 20 mV and aerobic-MFC from 35-47 mV at 1 kΩ external load. The highest power density was achieved by FAB in anaerobic-MFC (FAB = 104 mW/m[2], MFC = 98 mW/m[2]) and aerobic-MFC integrated system (FAB = 59 mW/m[2], MFC = 42 mW/m[2]).

CONCLUSIONS: The ∆COD and CE between FAB and MFC could not be concluded because both setups were inserted in the same reactor. The integrated system COD removal (78-97%) was higher than the solitary MFC treatment (68-78%). This study findings support the FAB+ integrated system could be applied for real applications and improve performance. However, it might depend on influent COD, the microbial nature, and ∆COD in FAB+ and MFC, which requires further study.}, } @article {pmid38646063, year = {2024}, author = {Toma, TT and Wang, Y and Gahlmann, A and Acton, ST}, title = {DeepSeeded: Volumetric Segmentation of Dense Cell Populations with a Cascade of Deep Neural Networks in Bacterial Biofilm Applications.}, journal = {Expert systems with applications}, volume = {238}, number = {Pt D}, pages = {}, doi = {10.1016/j.eswa.2023.122094}, pmid = {38646063}, issn = {0957-4174}, abstract = {Accurate and automatic segmentation of individual cell instances in microscopy images is a vital step for quantifying the cellular attributes, which can subsequently lead to new discoveries in biomedical research. In recent years, data-driven deep learning techniques have shown promising results in this task. Despite the success of these techniques, many fail to accurately segment cells in microscopy images with high cell density and low signal-to-noise ratio. In this paper, we propose a novel 3D cell segmentation approach DeepSeeded, a cascaded deep learning architecture that estimates seeds for a classical seeded watershed segmentation. The cascaded architecture enhances the cell interior and border information using Euclidean distance transforms and detects the cell seeds by performing voxel-wise classification. The data-driven seed estimation process proposed here allows segmenting touching cell instances from a dense, intensity-inhomogeneous microscopy image volume. We demonstrate the performance of the proposed method in segmenting 3D microscopy images of a particularly dense cell population called bacterial biofilms. Experimental results on synthetic and two real biofilm datasets suggest that the proposed method leads to superior segmentation results when compared to state-of-the-art deep learning methods and a classical method.}, } @article {pmid38644015, year = {2024}, author = {Zhou, M and Han, Y and Zhuo, Y and Yu, F and Hu, G and Peng, D}, title = {Effect of initial ammonium concentration on a one-stage partial nitrification/anammox biofilm system: Nitrogen removal performance and the microbial community.}, journal = {Journal of environmental sciences (China)}, volume = {143}, number = {}, pages = {176-188}, doi = {10.1016/j.jes.2023.07.026}, pmid = {38644015}, issn = {1001-0742}, abstract = {One-stage partial nitrification coupled with anammox (PN/A) technology effectively reduces the energy consumption of a biological nitrogen removal system. Inhibiting nitrite-oxidizing bacteria (NOB) is essential for this technology to maintain efficient nitrogen removal performance. Initial ammonium concentration (IAC) affects the degree of inhibited NOB. In this study, the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm reactor. The results showed that nitrogen removal efficiency decreased from 82.49% ± 1.90% to 64.57% ± 3.96% after the IAC was reduced from 60 to 20 mg N/L, while the nitrate production ratio increased from 13.87% ± 0.90% to 26.50% ± 3.76%. NOB activity increased to 1,133.86 mg N/m[2]/day after the IAC decreased, approximately 4-fold, indicating that the IAC plays an important inhibitory role in NOB. The rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the IAC. The analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community structure. Ca. Brocadia and Ca. Jettenia were the main anammox bacteria, and Nitrosomonas and Nitrospira were the main AOB and NOB, respectively. IAC did not affect the difference in growth between Ca. Brocadia and Ca. Jettenia. Thus, modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations.}, } @article {pmid38643952, year = {2024}, author = {Zhou, W and Hao, J and Guo, Y and Zhao, C and Zhang, M and Zhang, S and Han, F}, title = {Revealing bioresponses of biofilm and flocs to salinity gradient in halophilic biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130727}, doi = {10.1016/j.biortech.2024.130727}, pmid = {38643952}, issn = {1873-2976}, abstract = {Understanding the different biological responses to salinity gradient between coexisting biofilm and flocs is crucial for regulating the ecological function of biofilm system. This study investigated performance, dynamics, and community assembly of biofilm system under 3 %-7% salinity gradient. The removal efficiency of NH4[+]-N remained stable and exceeded 93 % at 3 %-6% salinity, but decreased to below 80 % at 7 % salinity. The elevated salinity promoted the synthesis of extracellular polymer substrates, inhibited microbial respiration, and significantly regulated the microbial community structure. Compared to flocs, biofilm exhibited greater species diversity and richer Nitrosomonas. It was found diffusion limitations dominated the microbial community assembly under the salinity gradient. And microbial network revealed positive interactions predominated the microbial relationships, designating norank Spirochaetaceae, unclassified Micrococcales, Corynebacterium, and Pusillimonas as keystone species. Moreover, distinct salinity preferences in nitrogen transformation-related genes were observed. This study can improve the understanding to the regulation of biofilm systems to salt stresses.}, } @article {pmid38643850, year = {2024}, author = {Tabassum, N and Jeong, GJ and Jo, DM and Khan, F and Kim, YM}, title = {Attenuation of biofilm and virulence factors of Pseudomonas aeruginosa by tetramethylpyrazine-gold nanoparticles.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106658}, doi = {10.1016/j.micpath.2024.106658}, pmid = {38643850}, issn = {1096-1208}, abstract = {Pseudomonas aeruginosa is often identified as the causative agent in nosocomial infections. Their adapted resistance makes them strong towards antimicrobial treatments. They protect and empower their survival behind strong biofilm architecture that works as their armor toward antimicrobial therapy. Additionally, P. aeruginosa generates virulence factors, contributing to chronic infection and recalcitrant phenotypic characteristics. The current study utilizes the benevolence of nanotechnology to develop an alternate technique to control the spreading of P. aeruginosa by limiting its biofilm and virulence development. This study used a natural compound, tetramethylpyrazine, to generate gold nanoparticles. Tetramethylpyrazine-gold nanoparticles (Tet-AuNPs) were presented in spherical shapes, with an average size of 168 ± 52.49 nm and a zeta potential of -12.22 ± 2.06 mV. The minimum inhibition concentration (MIC) of Tet-AuNPs that proved more than 90% effective in inhibiting P. aeruginosa was 256 μg/mL. Additionally, it also shows antibacterial activities against Staphylococcus aureus (MIC, 256 μg/mL), Streptococcus mutans (MIC, 128 μg/mL), Klebsiella pneumoniae (MIC, 128 μg/mL), Listeria monocytogenes (MIC, 256 μg/mL), and Escherichia coli (MIC, 256 μg/mL). The sub-MIC values of Tet-AuNPs significantly inhibited the early-stage biofilm formation of P. aeruginosa. Moreover, this concentration strongly affected hemolysis, protease activity, and different forms of motilities in P. aeruginosa. Additionally, Tet-AuNPs destroyed the well-established mature biofilm of P. aeruginosa. The expression of genes linked with the biofilm formation and virulence in P. aeruginosa treated with sub-MIC doses of Tet-AuNPs was shown to be significantly suppressed. Gene expression studies support biofilm- and virulence-suppressing effects of Tet-AuNPs at the phenotypic level.}, } @article {pmid38643226, year = {2024}, author = {Ahmed, GE and Elshahid, ZA and El-Sawy, ER and Abdel-Aziz, MS and Abdel-Aziem, A}, title = {Synthesis, biofilm formation inhibitory, and inflammation inhibitory activities of new coumarin derivatives.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {9106}, pmid = {38643226}, issn = {2045-2322}, abstract = {Coumarins are heterocycles of great interest in the development of valuable active structures in chemistry and biological domains. The ability of coumarins to inhibit biofilm formation of Gram positive bacterium (Staphylococcus aureus), Gram negative bacterium (Escherichia coli) as well as the methicillin-resistant S. aureus (MRSA) has been previously described. In the present work, new hybrid coumarin-heterocycles have been synthesized via the reaction of coumarin-6-sulfonyl chloride and 6-aminocoumarin with different small heterocycle moieties. The biological efficacy of the new compounds was evaluated towards their ability to inhibit biofilm formation and their anti-inflammatory properties. The antimicrobial activities of the newly synthesized compounds were tested against Gram positive bacterium (S. aureus ATCC 6538), Gram negative bacterium (E. coli ATCC 25922), yeast (Candida albicans ATCC 10231) and the fungus (Aspergillus niger NRRL-A326). Compounds 4d, 4e, 4f, 6a and 9 showed significant MIC and MBC values against S. aureus, E. coli, C. albicans, and methicillin-resistant S. aureus (MRSA) with especial incidence on compound 9 which surpasses all the other compounds giving MIC and MBC values of (4.88 and 9.76 µg/mL for S. aureus), (78.13 and 312.5 µg/mL for E. coli), (9.77 and 78.13 µg/mL for C. albicans), and (39.06 and 76.7 µg/mL for MRSA), respectively. With reference to the antibiofilm activity, compound 9 exhibited potent antibiofilm activity with IC50 of 60, 133.32, and 19.67 µg/mL against S. aureus, E. coli, and MRSA, (respectively) considering the reference drug (neomycin). Out of all studied compounds, the anti-inflammatory results indicated that compound 4d effectively inhibited nitric oxide production in lipopolysaccharide-(LPS-) stimulated RAW264.7 macrophage cells, giving NO% inhibition of 70% compared to Sulindac (55.2%).}, } @article {pmid38642854, year = {2024}, author = {Cichos, KH and Christie, MC and Ponce, BA and Ghanem, ES}, title = {Biofilm Growth on Orthopaedic Cerclage Materials: Non-metallic Polymers Are Less Resistant to Methicillin-Resistant Staphylococcus Aureus Bacterial Adhesion.}, journal = {The Journal of arthroplasty}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.arth.2024.04.042}, pmid = {38642854}, issn = {1532-8406}, abstract = {INTRODUCTION: Data on bacterial adhesion to cerclage cables is sparse. We aimed to compare five cerclage products for methicillin-resistant Staphylococcus aureus (MRSA) adhesion to determine: Are non-metallic polymer cables more resistant to bacterial adhesion than common metallic wires and cables?

MATERIALS AND METHODS: The following five cerclage products were compared: 1) monofilament stainless steel (SS) wires; 2) multifilament SS cables; 3) multifilament cobalt chrome (CoCr) cables; 4) multifilament Vitalium alloy (cobalt-chrome-molybdenum [Co-Cr-Mo]) cables; and 5) multifilament non-metallic polymer cables. Each was cut into 2 cm lengths and placed into 12-well plates. Of the wells, five were wire or cables in trypticase soy broth (TSB) with MRSA, with the remaining wells being appropriate controls incubated for 24 hours at 37 degrees C and 5% CO2 with shaking. Wires and cables were prepared, and randomly imaged via scanning electron microscopy (SEM), with bacterial counts performed on 3 images of 3 different wires or cables per study group. The SEM technician and counting investigator were blinded. Additionally, SS wire and polymer cables were analyzed by microcalorimetry for metabolic activity and bacterial load.

RESULTS: Bacterial attachment differed significantly between study groups in the middle section (P = 0.0003). Post-hoc comparison showed no difference between groups individually (all P > 0.05) apart from polymer cables (median 551 bacteria) having significantly increased attached bacteria compared to the Vitallium alloy cable (157, P = 0.0004), SS cable (101, P = 0.0004), and SS wire (211, P = 0.0004). There was no difference between polymer and CoCr cables (133, P = 0.056). Microcalorimetry supported these results, as polymer cables had a shorter time to max heat flow (6.2 versus 7.5 hours, P = 0.006), increased max heat flow (117 versus 64 uW, P = 0.045), and increased colony-forming units, indicating an increased bacterial load compared to SS wires. ConclusionThis in vitro study demonstrates that polymer cables have increased MRSA adhesion compared to common metallic wires and cables. Future studies are necessary to confirm the translation of increased bacterial adherence on polymer cables to increased rates of orthopaedic infections.}, } @article {pmid38642681, year = {2024}, author = {Nirmal, GR and Lin, ZC and Chiu, TS and Alalaiwe, A and Liao, CC and Fang, JY}, title = {Chemo-photothermal therapy of chitosan/gold nanorod clusters for antibacterial treatment against the infection of planktonic and biofilm MRSA.}, journal = {International journal of biological macromolecules}, volume = {268}, number = {Pt 1}, pages = {131673}, doi = {10.1016/j.ijbiomac.2024.131673}, pmid = {38642681}, issn = {1879-0003}, abstract = {Bacterial infections trigger inflammation and impede the closure of skin wounds. The misuse of antibiotics exacerbates skin infections by generating multidrug-resistant bacteria. In this study, we developed chemo-photothermal therapy (chemo-PTT) based on near-infrared (NIR)-irradiated chitosan/gold nanorod (GNR) clusters as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents. The nanocomposites exhibited an average size of 223 nm with a surface charge of 36 mV. These plasmonic nanocomposites demonstrated on-demand and rapid hyperthermal action under NIR. The combined effect of positive charge and PTT by NIR-irradiated nanocomposites resulted in a remarkable inhibition rate of 96 % against planktonic MRSA, indicating a synergistic activity compared to chitosan nanoparticles or GNR alone. The nanocomposites easily penetrated the biofilm matrix. The combination of chemical and photothermal treatments by NIR-stimulated clusters significantly damaged the biofilm structure, eradicating MRSA inside the biomass. NIR-irradiated chitosan/GNR clusters increased the skin temperature of mice by 13 °C. The plasmonic nanocomposites induced negligible skin irritation in vivo. In summary, this novel nanosystem demonstrated potent antibacterial effects against planktonic and biofilm MRSA, showcasing the possible efficacy in treating skin infections.}, } @article {pmid38642641, year = {2024}, author = {Savadiya, B and Pandey, G and Misra, SK}, title = {Remediation of Pharmacophoric Laboratory Waste by using Biodegradable Carbon Nanoparticles of Bacterial Biofilm Origin.}, journal = {Environmental research}, volume = {}, number = {}, pages = {118969}, doi = {10.1016/j.envres.2024.118969}, pmid = {38642641}, issn = {1096-0953}, abstract = {Research laboratories generate a broad range of hazardous pharmacophoric chemical contaminants, from drugs to dyes used during various experimental procedures. In the recent past, biological methods have demonstrated great potential in the remediation of such contaminants. However, the presence of pharmacophoric chemicals containing antibiotics, xenobiotics, and heavy metals suppresses the growth and survivability of used microbial agents, thus decreasing the overall efficiency of biological remediation processes. Bacterial biofilm is a natural arrangement to counter some of these inhibitions but its use in a systemic manner, portable devices, and pollutant remediation plants post serious challenges. This could be countered by synthesizing a biodegradable carbon nanoparticle from bacterial biofilm. In this study, extracellular polymeric substance-based carbon nanoparticles (Bio-EPS-CNPs) were synthesized from bacterial biofilm derived from Bacillus subtilis NCIB 3610, as a model bacterial system. The produced Bio-EPS-CNPs were investigated for physiochemical properties by dynamic light scattering, optical, Fourier-transformed infrared, and Raman spectroscopy techniques, whereas X-ray diffraction study, scanning electron microscopy, and transmission electron microscopy were used to investigate structural and morphological features. The Bio-EPS-CNPs exhibited negative surface charge with spherical morphology having a uniform size of sub-100 nm. The maximum remediation of some laboratory-produced pharmacophoric chemicals was achieved through a five-round scavenging process and confirmed by UV/Vis spectroscopic analysis with respect to the used pharmacophore. This bioinspired remediation of used pharmacophoric chemicals was achieved through the mechanism of surface adsorption via hydrogen bonding and electrostatic interactions, as revealed by different characterizations. Further experiments were performed to investigate the effects of pH, temperature, stirring, and the protocol of scavenging to establish Bio-EPS-CNP as a possible alternative to be used in research laboratories for efficient removal of pharmacophoric chemicals by incorporating it in a portable, filter-based device.}, } @article {pmid38642171, year = {2024}, author = {Araujo, TT and Dionizio, A and Carvalho, TS and Boas Feitosa, CMV and Vertuan, M and Câmara, JVF and Henrique-Silva, F and Marchetto, R and Chiaratti, MR and Santos, AC and Alves, LO and Ferro, M and Buzalaf, MAR}, title = {Acquired enamel pellicle and biofilm engineering with a combination of acid-resistant proteins (CaneCPI-5, StN15, and Hemoglobin) for enhanced protection against dental caries - in vivo and in vitro investigations.}, journal = {Clinical oral investigations}, volume = {28}, number = {5}, pages = {261}, pmid = {38642171}, issn = {1436-3771}, support = {2019/08032-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2019/26070-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 302371/2018-4 ; 304554/2023-5//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {OBJECTIVE: This study was designed in two-legs. In the in vivo, we explored the potential of a rinse solution containing a combination (Comb) of 0.1 mg/mL CaneCPI-5 (sugarcane-derive cystatin), 1.88 × 10[- 5]M StN15 (statherin-derived peptide) and 1.0 mg/mL hemoglobin (Hb) to change the protein profile of the acquired enamel pellicle(AEP) and the microbiome of the enamel biofilm. The in vitro, was designed to reveal the effects of Comb on the viability and bacterial composition of the microcosm biofilm, as well as on enamel demineralization.

MATERIALS AND METHODS: In vivo study, 10 participants rinsed (10mL,1 min) with either deionized water (H2O-control) or Comb. AEP and biofilm were collected after 2 and 3 h, respectively, after rinsing. AEP samples underwent proteomics analysis, while biofilm microbiome was assessed via 16 S-rRNA Next Generation Sequencing(NGS). In vitro study, a microcosm biofilm protocol was employed. Ninety-six enamel specimens were treated with: 1)Phosphate-Buffered Solution-PBS(negative-control), 2)0.12%Chlorhexidine, 3)500ppmNaF and 4)Comb. Resazurin, colony-forming-units(CFU) and Transversal Microradiography(TMR) were performed.

RESULTS: The proteomic results revealed higher quantity of proteins in the Comb compared to control associated with immune system response and oral microbial adhesion. Microbiome showed a significant increase in bacteria linked to a healthy microbiota, in the Comb group. In the in vitro study, Comb group was only efficient in reducing mineral-loss and lesion-depth compared to the PBS.

CONCLUSIONS: The AEP modification altered the subsequent layers, affecting the initial process of bacterial adhesion of pathogenic and commensal bacteria, as well as enamel demineralization.

CLINICAL RELEVANCE: Comb group shows promise in shaping oral health by potentially introducing innovative approaches to prevent enamel demineralization and deter tooth decay.}, } @article {pmid38641883, year = {2024}, author = {Pethe, A and Debnath, M}, title = {Wastewater treatment using moving bed biofilm reactor technology: a case study of ceramic industry.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {96}, number = {4}, pages = {e11026}, doi = {10.1002/wer.11026}, pmid = {38641883}, issn = {1554-7531}, support = {EF/2019-20/QEO4-01//Manipal University Jaipur/ ; }, abstract = {Biological approaches and coagulation are frequently used to reduce the chemical oxygen demand (COD) for treatment of ceramic effluent water. The technology known as the moving bed biofilm reactor (MBBR) can accomplish this goal. Further, the process of emulsification-aided innovative MBBR using biosurfactants can be proposed for ceramic effluent treatment. In a step-by-step upgrading scheme, biosurfactants and a consortia of halophilic and halotolerant microbial culture was utilized for the treatment of the effluent water. Over the course of 21 days, a progressive decrease in COD of up to 95.79% was achieved. Over the next 48 h period, the biochemical oxygen demand (BOD) was reduced by 98.3%, while total suspended solids (TSS) decreased by 79.41%. With the use of this innovative MBBR technology, biofilm formation accelerated, lowering the COD, BOD, and TSS levels. This allows treated water to be used for further research on recycling it back into the ceramics sector and repurposing it for agricultural purposes. PRACTITIONER POINTS: Implementation of modified MBBR technology for the treatment of effluent water. Biosurfactants could reduce in the organic and inorganic loads. Increase in MLSS values with COD removal observed. The plant operations without the use of chemical coagulants was effective with biosurfactants. Biofilm formation on carriers was scraped and the presence of surfactin and rhamnolipid was confirmed.}, } @article {pmid38641593, year = {2024}, author = {Raj, K and Paul, D and Rishi, P and Shukla, G and Dhotre, D and YogeshSouche, }, title = {Decoding the role of oxidative stress resistance and alternative carbon substrate assimilation in the mature biofilm growth mode of Candida glabrata.}, journal = {BMC microbiology}, volume = {24}, number = {1}, pages = {128}, pmid = {38641593}, issn = {1471-2180}, abstract = {BACKGROUND: Biofilm formation is viewed as a vital mechanism in C. glabrata pathogenesis. Although, it plays a significant role in virulence but transcriptomic architecture and metabolic pathways governing the biofilm growth mode of C. glabrata remain elusive. The present study intended to investigate the genes implicated in biofilm growth phase of C. glabrata through global transcriptomic approach.

RESULTS: Functional analysis of Differentially expressed genes (DEGs) using gene ontology and pathways analysis revealed that upregulated genes are involved in the glyoxylate cycle, carbon-carbon lyase activity, pre-autophagosomal structure membrane and vacuolar parts whereas, down- regulated genes appear to be associated with glycolysis, ribonucleoside biosynthetic process, ribosomal and translation process in the biofilm growth condition. The RNA-Seq expression of eight selected DEGs (CgICL1, CgMLS1, CgPEP1, and CgNTH1, CgERG9, CgERG11, CgTEF3, and CgCOF1) was performed with quantitative real-time PCR (RT-qPCR). The gene expression profile of selected DEGs with RT-qPCR displayed a similar pattern of expression as observed in RNA-Seq. Phenotype screening of mutant strains generated for genes CgPCK1 and CgPEP1, showed that Cgpck1∆ failed to grow on alternative carbon substrate (Glycerol, Ethanol, Oleic acid) and similarly, Cgpep1∆ unable to grow on YPD medium supplemented with hydrogen peroxide. Our results suggest that in the absence of glucose, C. glabrata assimilate glycerol, oleic acid and generate acetyl coenzyme-A (acetyl-CoA) which is a central and connecting metabolite between catabolic and anabolic pathways (glyoxylate and gluconeogenesis) to produce glucose and fulfil energy requirements.

CONCLUSIONS: The study was executed using various approaches (transcriptomics, functional genomics and gene deletion) and it revealed that metabolic plasticity of C. glabrata (NCCPF-100,037) in biofilm stage modulates its virulence and survival ability to counter the stress and may promote its transition from commensal to opportunistic pathogen. The observations deduced from the present study along with future work on characterization of the proteins involved in this intricate process may prove to be beneficial for designing novel antifungal strategies.}, } @article {pmid38641269, year = {2024}, author = {Youssef Moustafa, AM and Fawzy, MM and Kelany, MS and Hassan, YA and Elsharaawy, RFM and Mustafa, FHA}, title = {Synthesis of new quaternized chitosan Schiff bases and their N-alkyl derivatives as antimicrobial and anti-biofilm retardants in membrane technology.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {131635}, doi = {10.1016/j.ijbiomac.2024.131635}, pmid = {38641269}, issn = {1879-0003}, abstract = {New quaternized salicylidene chitosan Schiff bases (QSCSBs) and their N-octyl derivatives (OQCs) have been synthesized and characterized, aiming to develop innovative antimicrobial and anti-biofilm agents. This research holds immense potential, as these compounds could be utilized as anti-biofouling additives in membrane technology in the future. The synthesis involved the modification of low molecular-weight-chitosan (LMC) through simultaneous Schiff base formation and quaternization processes to create QSCSBs. Subsequently, QSCSBs were catalytically reduced to form quaternized N-benzyl chitosan (QBCs) intermediates, which then underwent nucleophilic substitution reactions affording N-octyl quaternized chitosans (OQCs). Characterization techniques such as elemental, spectral, and microscopic analyses were used to confirm the successful synthesis of these materials. As membrane technology relies on surface charge, QSCSBs and OQCs with large zeta potentials could be used as positively charged additives. Moreover, SEM image revealed the regular distribution of pores and voids across the additives' surfaces raises intriguing questions about their implications for membrane performance. Meanwhile, the superior antibacterial and antibiofilm potential of these materials, particularly QSCSB2 and OQC2, indicate that the utilization of these compounds as anti-biofouling additives in membrane technology could significantly improve the performance and longevity of membranes used in various applications such as water treatment and desalination.}, } @article {pmid38640776, year = {2024}, author = {Ganesh, PS}, title = {4-hydroxy-3-methoxybenzaldehyde causes attrition of biofilm formation and quorum sensing-associated virulence factors of Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {163}, number = {}, pages = {105976}, doi = {10.1016/j.archoralbio.2024.105976}, pmid = {38640776}, issn = {1879-1506}, abstract = {OBJECTIVE: The present study investigated the effects of 4-hydroxy-3-methoxybenzaldehyde (4-H-3-MB) against Streptococcus mutans (S. mutans) using an in vitro cariogenic biofilm model.

DESIGN: The antimicrobial susceptibility of biofilm-forming S. mutans was evaluated by disc diffusion method. In vitro investigations were performed using crystal violet staining assay (biofilm assay), exopolysaccharide (EPS) assay, acid production, growth curve analysis, optical microscopic, and FE-SEM analyses to determine the antibiofilm activity of 4-H-3-MB.

RESULTS: S. mutans (SDC-05) was resistant to ampicillin, piperacillin/tazobactam and ceftriaxone, whereas the other strains of S. mutans (SDC-01, 02, 03 and SDC-04) were sensitive to all the antibiotics tested. 4-H-3-MB showed promising antibiofilm activity on S. mutans UA159 (79.81 %, 67.76 % and 56.31 %) and S. mutans SDC-05 (77.00 %, 59.48 % and 48.22 %) at the lowest concentration of 0.2, 0.1, 0.05 mg/ml. 4-H-3-MB did not inhibit bacterial growth even at concentrations 0.2 mg/ml. Similarly, 4-H-3-MB led to significant attrition in exopolysaccharide (EPS) and acid production by S. mutans UA159 and S. mutans (SDC-05) at the concentration of 0.2, 0.1 mg/ml, respectively. Optical microscopy and FE-SEM analysis 4-H-3-MB reduced the biofilm thickness of S. mutans UA159 and S. mutans SDC-05 relative to the untreated specimens.

CONCLUSION: 4-H-3-MB significantly inhibited biofilm formation by S. mutans in a dose-dependent manner. Hence, our findings indicate that the active principle of 4-H-3-MB could be used as a biofilm inhibiting agent against S. mutans.}, } @article {pmid38640499, year = {2024}, author = {Jakkampudi, T and Lin, Q and Mitra, S and Vijai, A and Qin, W and Kang, A and Chen, J and Ryan, E and Wang, R and Gong, Y and Heinrich, F and Song, J and Di, YP and Tristram-Nagle, S}, title = {Correction to "Lung SPLUNC1 Peptide Derivatives in the Lipid Membrane Headgroup Kill Gram-Negative Planktonic and Biofilm Bacteria".}, journal = {Biomacromolecules}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.biomac.4c00501}, pmid = {38640499}, issn = {1526-4602}, } @article {pmid38639582, year = {2024}, author = {Upadhyay, A and Pal, D and Kumar, A}, title = {Molecular drilling to combat salmonella typhi biofilm using L-Asparaginase via multiple targeting process.}, journal = {Expert opinion on therapeutic targets}, volume = {}, number = {}, pages = {}, doi = {10.1080/14728222.2024.2344699}, pmid = {38639582}, issn = {1744-7631}, abstract = {OBJECTIVES: Salmonella Typhibiofilm condition is showing as a major public health problem due to the developmentof antibiotic resistance and less available druggable target proteins.Therefore, we aimed to identify some more druggable targets of S. Typhibiofilm using computational drilling at the genome/proteome level so that thetarget shortage problem could be overcome and more antibiofilm agents could bedesigned in the future against the disease.

METHODS: We performed protein-protein dockingand interaction analysis between the homological identified target proteins of S.Typhi biofilm and a therapeutic protein L-Asparaginase.

RESULTS: We have identified some druggabletargets CsgD, BcsA, OmpR, CsgG, CsgE, and CsgF in S.Typhi. These targetsshowed high-binding affinity BcsA (-219.8 Kcal/mol) >csgF (-146.52 Kcal/mol) >ompR (-135.68 Kcal/mol) >CsgE (-134.66 Kcal/mol) >CsgG (-113.81 Kcal/mol) >CsgD(-95.39 Kcal/mol) with therapeutic enzyme L-Asparaginase through varioushydrogen-bonds and salt-bridge. We found six proteins of S. Typhi biofilm from the Csg family as druggable multiple targets.

CONCLUSION: This study provides insight intothe idea of identification of new druggable targets and their multipletargeting with L-Asparaginase to overcome target shortage in S. Typhibiofilm-mediated infections. Results further indicated that L-Asparaginasecould potentially be utilized as an antibiofilm biotherapeutic agent against S.Typhi.}, } @article {pmid38639133, year = {2024}, author = {Mamba, PP and Msagati, TAM and Mamba, BB and Motsa, MM and Nkambule, TTI}, title = {The removal of pathogenic bacteria and dissolved organic matter from freshwater using microporous membranes: insights into biofilm formation and fouling reversibility.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/08927014.2024.2339438}, pmid = {38639133}, issn = {1029-2454}, abstract = {Pathogenic bacteria in drinking-water pose a health risk to consumers, as they compromise the quality of portable water. Chemical disinfection of water containing dissolved organic matter (DOM) causes harmful disinfection by-products. In this work, 4-hydroxybenzoic acid (4-HBA) blended polyethersulfone membranes were fabricated and characterised using microscopic and spectroscopic techniques. The membranes were evaluated for the removal of bacteria and DOM from synthetic and environmental water. Permeate flux increased from 287.30 to 374.60 l m[-2] h[-1] at 3 bars when 4-HBA increased from 0 to 1.5 wt.%, suggesting that 4-HBA influenced the membrane's affinity for water. Furthermore, 4-HBA demonstrated antimicrobial properties by inhibiting bacterial growth. The membrane with 1 wt.% 4-HBA recorded 99.4 and 100% bacteria removal in synthetic and environmental water, respectively. Additionally, DOM removal of 55-73% was achieved. A flux recovery ratio (FRR) of 94.6% was obtained when a mixture of bacteria and humic acid was filtered, implying better fouling layer reversibility during cleaning. Furthermore, 100% FRR was achieved when a multimedia granular filtration step was installed prior to membrane filtration. The results illustrated that the membranes had a high permeate flux with low irreversible fouling. This indicated the potential of the membranes in treating complex feed streams using simple cleaning protocols.}, } @article {pmid38638833, year = {2024}, author = {Zhang, W and He, M and Kong, N and Niu, Y and Li, A and Yan, Y}, title = {Study on the inhibition activity and mechanism of Tanreqing against Klebsiella pneumoniae biofilm formation in vitro and in vivo.}, journal = {Frontiers in cellular and infection microbiology}, volume = {14}, number = {}, pages = {1368450}, pmid = {38638833}, issn = {2235-2988}, abstract = {OBJECTIVE: To evaluate the antibacterial effect of Tanreqing (TRQ) against K. pneumoniae and its inhibition activity on bacterial biofilm formation in vitro and in vivo, and to explore the mechanism of the inhibitory effects of TRQ on K. pneumoniae biofilm formation.

METHODS: An in vitro biofilm model of K. pneumoniae was established, and the impact of TRQ on biofilm formation was evaluated using crystal violet staining and scanning electron microscopy (SEM). Furthermore, the clearance effect of TRQ against K. pneumoniae in the biofilm was assessed using the viable plate counting method; q-RT PCR was used to evaluate the inhibitory effect of different concentrations of TRQ on the expression of biofilm-related genes in Klebsiella pneumoniae; The activity of quorum sensing signal molecule AI-2 was detected by Vibrio harveyi bioluminescence assay; Meanwhile, a guinea pig lung infection model of Klebsiella pneumoniae was constructed, and after treated with drugs, pathological analysis of lung tissue and determination of bacterial load in lung tissue were performed. The treatment groups included TRQ group, imipenem(IPM) group, TRQ+IPM group, and sterile saline group as the control.

RESULTS: The formation of K. pneumoniae biofilm was significantly inhibited by TRQ in vitro experiments. Furthermore, when combined with IPM, the clearance of K. pneumoniae in the biofilm was notably increased compared to the TRQ group and IPM group alone. q-RT PCR analysis revealed that TRQ down-regulated the expression of genes related to biofilm formation in K. pneumoniae, specifically luxS, wbbm, wzm, and lsrK, and also inhibited the activity of AI-2 molecules in the bacterium. In vivo experiments demonstrated that TRQ effectively treated guinea pig lung infections, resulting in reduced lung inflammation. Additionally, when combined with IPM, there was a significant reduction in the bacterial load in lung tissue.

CONCLUSION: TRQ as a potential therapeutic agent plays a great role in the treatment of K. pneumoniae infections, particularly in combination with conventional antibiotics. And TRQ can enhanced the clearance effect on the bacterium by inhibiting the K. pneumoniae biofilm formation, which provided experimental evidence in support of clinical treatment of TRQ against K. pneumoniae infections.}, } @article {pmid38637715, year = {2024}, author = {Taglialegna, A}, title = {Shaking up that sick feeling with biofilm sugars.}, journal = {Nature reviews. Microbiology}, volume = {}, number = {}, pages = {}, pmid = {38637715}, issn = {1740-1534}, } @article {pmid38637093, year = {2024}, author = {Melian, C and Ploper, D and Chehín, R and Vignolo, G and Castellano, P}, title = {Impairment of Listeria monocytogenes biofilm developed on industrial surfaces by Latilactobacillus curvatus CRL1579 bacteriocin.}, journal = {Food microbiology}, volume = {121}, number = {}, pages = {104491}, doi = {10.1016/j.fm.2024.104491}, pmid = {38637093}, issn = {1095-9998}, abstract = {The effect of lactocin AL705, bacteriocin produced by Latilactobacillus (Lat.) curvatus CRL1579 against Listeria biofilms on stainless steel (SS) and polytetrafluoroethylene (PTFE) coupons at 10 °C was investigated. L. monocytogenes FBUNT showed the greatest adhesion on both surfaces associated to the hydrophobicity of cell surface. Partially purified bacteriocin (800 UA/mL) effectively inhibited L. monocytogenes preformed biofilm through displacement strategy, reducing the pathogen by 5.54 ± 0.26 and 4.74 ± 0.05 log cycles at 3 and 6 days, respectively. The bacteriocin-producer decreased the pathogen biofilm by ∼2.84 log cycles. Control and Bac[-] treated samples reached cell counts of 7.05 ± 0.18 and 6.79 ± 0.06 log CFU/cm[2] after 6 days of incubation. Confocal scanning laser microscopy (CLSM) allowed visualizing the inhibitory effect of lactocin AL705 on L. monocytogenes preformed biofilms under static and hydrodynamic flow conditions. A greater effect of the bacteriocin was found at 3 days independently of the surface matrix and pathogen growth conditions at 10 °C. As a more realistic approach, biofilm displacement strategy under continuous flow conditions showed a significant loss of biomass, mean thickness and substratum coverage of pathogen biofilm. These findings highlight the anti-biofilm capacity of lactocin AL705 and their potential application in food industries.}, } @article {pmid38637079, year = {2024}, author = {Abi Assaf, J and Holden, ER and Trampari, E and Webber, MA}, title = {Common food preservatives impose distinct selective pressures on Salmonella Typhimurium planktonic and biofilm populations.}, journal = {Food microbiology}, volume = {121}, number = {}, pages = {104517}, doi = {10.1016/j.fm.2024.104517}, pmid = {38637079}, issn = {1095-9998}, abstract = {Food preservatives are crucial in controlling microbial growth in processed foods to maintain food safety. Bacterial biofilms pose a threat in the food chain by facilitating persistence on a range of surfaces and food products. Cells in a biofilm are often highly tolerant of antimicrobials and can evolve in response to antimicrobial exposure. Little is known about the efficacy of preservatives against biofilms and their potential impact on the evolution of antimicrobial resistance. In this study we investigated how Salmonella enterica serovar Typhimurium responded to subinhibitory concentrations of four food preservatives (sodium chloride, potassium chloride, sodium nitrite or sodium lactate) when grown planktonically and in biofilms. We found that each preservative exerted a unique selective pressure on S. Typhimurium populations. There was a trade-off between biofilm formation and growth in the presence of three of the four preservatives, where prolonged preservative exposure resulted in reduced biofilm biomass and matrix production over time. All three preservatives selected for mutations in global stress response regulators rpoS and crp. There was no evidence for any selection of cross-resistance to antibiotics after preservative exposure. In conclusion, we showed that preservatives affect biofilm formation and bacterial growth in a compound specific manner. We showed trade-offs between biofilm formation and preservative tolerance, but no antibiotic cross-tolerance. This indicates that bacterial adaptation to continuous preservative exposure, is unlikely to affect food safety or contribute to antibiotic resistance.}, } @article {pmid38636891, year = {2024}, author = {Shaghayegh, G and Cooksley, C and Bouras, G and Panchatcharam, BS and Feizi, S and Javadian, S and Ramezanpour, M and Fenix, KA and Wormald, PJ and Psaltis, AJ and Vreugde, S}, title = {[1]S. aureus biofilm properties correlate with immune B cell subset frequencies and severity of chronic rhinosinusitis.}, journal = {Clinical immunology (Orlando, Fla.)}, volume = {}, number = {}, pages = {110221}, doi = {10.1016/j.clim.2024.110221}, pmid = {38636891}, issn = {1521-7035}, abstract = {Staphylococcus aureus mucosal biofilms are associated with recalcitrant chronic rhinosinusitis (CRS). However, S. aureus colonisation of sinus mucosa is frequent in the absence of mucosal inflammation. This questions the relevance of S. aureus biofilms in CRS etiopathogenesis. This study aimed to investigate whether strain-level variation in in vitro-grown S. aureus biofilm properties relates to CRS disease severity, in vitro toxicity, and immune B cell responses in sinonasal tissue from CRS patients and non-CRS controls. S. aureus clinical isolates, tissue samples, and matched clinical datasets were collected from CRS patients with nasal polyps (CRSwNP), CRS without nasal polyps (CRSsNP), and controls. B cell responses in tissue samples were characterised by FACS. S. aureus biofilms were established in vitro, followed by measuring their properties of metabolic activity, biomass, colony-forming units, and exoprotein production. S. aureus virulence was evaluated using whole-genome sequencing, mass spectrometry and application of S. aureus biofilm exoproteins to air-liquid interface cultures of primary human nasal epithelial cells (HNEC-ALI). In vitro S. aureus biofilm properties were correlated with increased CRS severity scores, infiltration of antibody-secreting cells and loss of regulatory B cells in tissue samples. Biofilm exoproteins from S. aureus with high biofilm metabolic activity had enriched virulence genes and proteins, and negatively affected the barrier function of HNEC-ALI cultures. These findings support the notion of strain-level variation in S. aureus biofilms to be critical in the pathophysiology of CRS.}, } @article {pmid38636465, year = {2024}, author = {Rattanapakdeekul, N and Lapirattanakul, J and Tosrisawatkasem, O and Surarit, R and Smutkeeree, A}, title = {Evaluation of Streptococcus mutans biofilm formation and acidogenicity of infant milk formulas for treating cow milk allergy: An in vitro study.}, journal = {Caries research}, volume = {}, number = {}, pages = {}, doi = {10.1159/000538882}, pmid = {38636465}, issn = {1421-976X}, abstract = {INTRODUCTION: When infants cannot consume breast milk, the most commonly available alternative milk formula is cow milk-based. Due to a rise in the prevalence of cow milk protein allergy (CMPA) among children, this study aimed to assess the biofilm formation and acidogenicity of cow milk-based formulas as well as milk formulas suggested for children with CMPA.

METHODS: Cow milk-based formulas with 0%, 10%, or 18% sucrose added, partially hydrolyzed formula (pHF), extensively hydrolyzed formula (eHF), amino acid-based formula (AAF), and soy-based formulas with 0%, or 11% sucrose added were evaluated. Streptococcus mutans was used as a representative microorganism associated with caries. The acidogenicity after 24-h incubation was assessed by the pH of the formed biofilm and lactic acid formation. Biofilm formation was quantified using crystal violet staining. Additionally, the biofilm characteristics were determined using confocal laser scanning microscopy (CLSM). Comparisons were made among formulas without added sucrose to observe protein-based differences. Furthermore, formulas with different sucrose percentages were compared to explore the impact of sucrose content.

RESULTS: When comparing the formulas without added sucrose, the biofilm formation in the cow milk-based formula and pHF were significantly greater than the soy-based formula, eHF, and AAF. In the presence of S. mutans, all formulas reduced the biofilm pH below the critical enamel pH. The cow milk-based formula and AAF showed a significantly lower biofilm pH than the pHF, soy-based, and eHF groups, while the lactic acid production was markedly higher in the cow milk-based formula, pHF and AAF, compared with the eHF and soy-based formula. Adding sucrose into the cow milk-based and soy-based formulas substantially increased biofilm mass. The biofilm pH of the cow milk-based formulas, with or without sucrose, was significantly lower than that of the soy-based formulas. The CLSM indicated distinct biofilm characteristics among the different protein-based formulas, with sucrose supplementation promoting S. mutans aggregation in cow milk-based formula biofilm and increased density and intact biofilm in the soy-based formula.

CONCLUSION: All assessed milk formulas had caries-inducing factors, including those without supplemental sucrose. Among them, the eHF demonstrated the least caries-inducing factors, attributed to its minimal biofilm formation and the highest biofilm pH.}, } @article {pmid38636417, year = {2024}, author = {Liu, Y and Li, J and Su, J and Li, X and Li, X}, title = {Simultaneous removal of ammonia nitrogen, calcium and cadmium in a biofilm reactor based on microbial-induced calcium precipitation: Optimization of conditions, mechanism and community biological response.}, journal = {Journal of environmental management}, volume = {358}, number = {}, pages = {120912}, doi = {10.1016/j.jenvman.2024.120912}, pmid = {38636417}, issn = {1095-8630}, abstract = {With the enhancement of environmental governance regulations, the discharge requirements for reverse osmosis wastewater have become increasingly stringent. This study proposes an innovative approach utilizing heterotrophic nitrification and aerobic denitrification (HNAD)-based biomineralization technology, combined with coconut palm silk loaded biochar, to offer a novel solution for resource-efficient and eco-friendly treatment of reverse osmosis wastewater. Zobellella denitrificans sp. LX16 were loaded onto modified coir silk and showed removal efficiencies of up to 97.38, 94.58, 86.24, and 100% for NH4[+]-N (65 mg L[-1]), COD (900 mg L[-1]), Ca[2+] (180 mg L[-1]), and Cd[2+] (25 mg L[-1]). Analysis of the metabolites of microorganisms reveals that coconut palm silk loaded with deciduous biochar (BCPS) not only exerts a protective effect on microorganisms, but also enhances their growth, metabolism, and electron transfer capabilities. Characterization of precipitation phenomena elucidated the mechanism of Cd[2+] removal via ion exchange, precipitation, and adsorption. Employing high-throughput and KEGG functional analyses has confirmed the biota environmental response strategies and the identification of key genes like HNAD.}, } @article {pmid38635841, year = {2024}, author = {Youngblom, MA and Smith, TM and Murray, HJ and Pepperell, CS}, title = {Adaptation of the Mycobacterium tuberculosis transcriptome to biofilm growth.}, journal = {PLoS pathogens}, volume = {20}, number = {4}, pages = {e1012124}, doi = {10.1371/journal.ppat.1012124}, pmid = {38635841}, issn = {1553-7374}, abstract = {Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), is a leading global cause of death from infectious disease. Biofilms are increasingly recognized as a relevant growth form during M. tb infection and may impede treatment by enabling bacterial drug and immune tolerance. M. tb has a complicated regulatory network that has been well-characterized for many relevant disease states, including dormancy and hypoxia. However, despite its importance, our knowledge of the genes and pathways involved in biofilm formation is limited. Here we characterize the biofilm transcriptomes of fully virulent clinical isolates and find that the regulatory systems underlying biofilm growth vary widely between strains and are also distinct from regulatory programs associated with other environmental cues. We used experimental evolution to investigate changes to the transcriptome during adaptation to biofilm growth and found that the application of a uniform selection pressure resulted in loss of strain-to-strain variation in gene expression, resulting in a more uniform biofilm transcriptome. The adaptive trajectories of transcriptomes were shaped by the genetic background of the M. tb population leading to convergence on a sub-lineage specific transcriptome. We identified widespread upregulation of non-coding RNA (ncRNA) as a common feature of the biofilm transcriptome and hypothesize that ncRNA function in genome-wide modulation of gene expression, thereby facilitating rapid regulatory responses to new environments. These results reveal a new facet of the M. tb regulatory system and provide valuable insight into how M. tb adapts to new environments.}, } @article {pmid38634060, year = {2024}, author = {Lu, L and Zhao, Y and Li, M and Wang, X and Zhu, J and Liao, L and Wang, J}, title = {Contemporary strategies and approaches for characterizing composition and enhancing biofilm penetration targeting bacterial extracellular polymeric substances.}, journal = {Journal of pharmaceutical analysis}, volume = {14}, number = {4}, pages = {100906}, pmid = {38634060}, issn = {2214-0883}, abstract = {Extracellular polymeric substances (EPS) constitutes crucial elements within bacterial biofilms, facilitating accelerated antimicrobial resistance and conferring defense against the host's immune cells. Developing precise and effective antibiofilm approaches and strategies, tailored to the specific characteristics of EPS composition, can offer valuable insights for the creation of novel antimicrobial drugs. This, in turn, holds the potential to mitigate the alarming issue of bacterial drug resistance. Current analysis of EPS compositions relies heavily on colorimetric approaches with a significant bias, which is likely due to the selection of a standard compound and the cross-interference of various EPS compounds. Considering the pivotal role of EPS in biofilm functionality, it is imperative for EPS research to delve deeper into the analysis of intricate compositions, moving beyond the current focus on polymeric materials. This necessitates a shift from heavy reliance on colorimetric analytic methods to more comprehensive and nuanced analytical approaches. In this study, we have provided a comprehensive summary of existing analytical methods utilized in the characterization of EPS compositions. Additionally, novel strategies aimed at targeting EPS to enhance biofilm penetration were explored, with a specific focus on highlighting the limitations associated with colorimetric methods. Furthermore, we have outlined the challenges faced in identifying additional components of EPS and propose a prospective research plan to address these challenges. This review has the potential to guide future researchers in the search for novel compounds capable of suppressing EPS, thereby inhibiting biofilm formation. This insight opens up a new avenue for exploration within this research domain.}, } @article {pmid38633196, year = {2024}, author = {Mohammed, AR and El-Said, EI and Abd ElAal, SF and Kamal, RM}, title = {Screening of antibiogram, virulence factors, and biofilm production of Staphylococcus aureus and the bio-control role of some probiotics as alternative antibiotics.}, journal = {Open veterinary journal}, volume = {14}, number = {1}, pages = {176-185}, pmid = {38633196}, issn = {2218-6050}, abstract = {BACKGROUND: Food safety is a serious challenge in the face of increasing population and diminishing resources. Staphylococcus aureus is a critical foodborne pathogen characterized by its capability to secret a diverse range of heat-resistant enterotoxins. Antibiotic usage in dairy herds resulted in the occurrence of antimicrobial resistance (AMR) patterns among bacterial species, which were consequently transmitted to humans via dairy products. Lactic acid bacteria (LAB) produce bacteriocins, which provide an excellent source of natural antimicrobials with the further advantage of being environmentally friendly and safe.

AIM: Detection of multidrug resistance (MDR) S. aureus isolates in concerned samples, molecular characteristics, biofilm production, and the inhibitory role of LAB against it.

METHODS: Random samples of raw milk and other dairy products were analyzed for S. aureus isolation. Phenotypic and genotypic assessment of AMR was performed, in addition to detection of classical enterotoxin genes of S. aureus. Finally, evaluation of the antimicrobial action of some Lactobacillus strains against S. aureus.

RESULTS: Incidence rates of presumptive S. aureus in raw milk, Kariesh cheese, and yogurt samples were 50%, 40%, and 60%, respectively. The highest resistance of S. aureus was to Kanamycin (100%) and Nalidixic acid (89.3%), respectively. (78.66%) of S. aureus were MDR. 11.1% of S. aureus carried mecA gene. In concern with enterotoxins genes, PCR showed that examined isolates harbored sea with a percentage of (22.2%), while sed was found in (11.1%) of isolates. Regarding biofilm production, (88.88%) of S. aureus were biofilm producers. Finally, agar well diffusion showed that Lactobacillus acidophilus had the strongest antimicrobial action against S. aureus with inhibition zone diameter ranging from 18 to 22 mm.

CONCLUSION: There is a widespread prevalence of MDR S. aureus in raw milk and dairy products. Production of staphylococcal enterotoxins, as well as biofilm production are responsible for public health risks. Therefore, installing proper hygienic routines and harsh food safety policies at food chain levels is substantial.}, } @article {pmid38633171, year = {2024}, author = {Elshazely, RMY and Amer, IH and Aal, SFAA and Aal, SFAA and Tahoun, ABMB}, title = {Antibacterial effect of Moringa oleifera on Staphylococcus aureus and Pseudomonas aeruginosa isolated from raw milk and some dairy products with special reference to biofilm gene expression.}, journal = {Open veterinary journal}, volume = {14}, number = {1}, pages = {164-175}, pmid = {38633171}, issn = {2218-6050}, abstract = {BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) are well defined as food poisoning pathogens that are highly resistant and need continuous studies.

AIM: The purpose of the work was to examine phenotypic and genotypic characteristics of both P. aeruginosa and S. aureus, and treatment trials with medicinal plants.

METHODS: Samples were examined for isolation of P. aeruginosa and S. aureus on selective media followed by biochemical confirmation, biofilm formation, genes detection, and expression of P. aeruginosa pslA biofilm gene was performed by quantitative real-time polymerase chain reaction after treatment with 0.312 mg/ml Moringa oleifera aqueous extract as a minimum inhibitory concentration.

RESULTS: The highest isolation rate of P. aeruginosa was 20% from both raw milk and Kariesh cheese, followed by 16% and 12% from ice cream and processed cheese, respectively, while the highest isolation rate of S. aureus was 36% from raw milk followed by 28% in ice cream and 16% in both Kariesh cheese and processed cheese. 30% of P. aeruginosa isolates were biofilm producers, while only 21% of S. aureus isolates were able to produce biofilm. The P. aeruginosa isolates harbor virulence-associated genes nan1, exoS, toxA, and pslA at 100%, 80%, 40%, and 40%, respectively. Staphylococcus aureus SEs genes were examined in S. aureus strains, where SEA and SEB genes were detected with 60%, but no isolate harbored SEC, SED, or SEE. The significant fold change of P. aeruginosa pslA expression was 0.40332 after treatment with M. oleifera aqueous extract.

CONCLUSION: Pseudomonas aeruginosa and S. aureus harbor dangerous virulence genes that cause food poisoning, but M. oleifera extract could minimize their action.}, } @article {pmid38629727, year = {2024}, author = {Xue, Y and Yu, C and Ouyang, H and Huang, J and Kang, X}, title = {Uncovering the Molecular Composition and Architecture of the Bacillus subtilis Biofilm via Solid-State NMR Spectroscopy.}, journal = {Journal of the American Chemical Society}, volume = {}, number = {}, pages = {}, doi = {10.1021/jacs.4c00889}, pmid = {38629727}, issn = {1520-5126}, abstract = {The complex and dynamic compositions of biofilms, along with their sophisticated structural assembly mechanisms, endow them with exceptional capabilities to thrive in diverse conditions that are typically unfavorable for individual cells. Characterizing biofilms in their native state is significantly challenging due to their intrinsic complexities and the limited availability of noninvasive techniques. Here, we utilized solid-state nuclear magnetic resonance (NMR) spectroscopy to analyze Bacillus subtilis biofilms in-depth. Our data uncover a dynamically distinct organization within the biofilm: a dominant, hydrophilic, and mobile framework interspersed with minor, rigid cores of limited water accessibility. In these heterogeneous rigid cores, the major components are largely self-assembled. TasA fibers, the most robust elements, further provide a degree of mechanical support for the cell aggregates and some lipid vesicles. Notably, rigid cell aggregates can persist even without the major extracellular polymeric substance (EPS) polymers, although this leads to slight variations in their rigidity and water accessibility. Exopolysaccharides are exclusively present in the mobile domain, playing a pivotal role in its water retention property. Specifically, all water molecules are tightly bound within the biofilm matrix. These findings reveal a dual-layered defensive strategy within the biofilm: a diffusion barrier through limited water mobility in the mobile phase and a physical barrier posed by limited water accessibility in the rigid phase. Complementing these discoveries, our comprehensive, in situ compositional analysis is not only essential for delineating the sophisticated biofilm architecture but also reveals the presence of alternative genetic mechanisms for synthesizing exopolysaccharides beyond the known pathway.}, } @article {pmid38629215, year = {2024}, author = {Quan, K and Mao, Z and Lu, Y and Qin, Y and Wang, S and Yu, C and Bi, X and Tang, H and Ren, X and Chen, D and Cheng, Y and Wang, Y and Zheng, Y and Xia, D}, title = {Composited silk fibroins ensured adhesion stability and magnetic controllability of Fe3O4-nanoparticle coating on implant for biofilm treatment.}, journal = {Materials horizons}, volume = {}, number = {}, pages = {}, doi = {10.1039/d4mh00097h}, pmid = {38629215}, issn = {2051-6355}, abstract = {Magnetic propulsion of nano-/micro-robots is an effective way to treat implant-associated infections by physically destroying biofilm structures to enhance antibiotic killing. However, it is hard to precisely control the propulsion in vivo. Magnetic-nanoparticle coating that can be magnetically pulled off does not need precise control, but the requirement of adhesion stability on an implant surface restricts its magnetic responsiveness. Moreover, whether the coating has been fully pulled-off or not is hard to ensure in real-time in vivo. Herein, composited silk fibroins (SFMA) are optimized to stabilize Fe3O4 nanoparticles on a titanium surface in a dry environment; while in an aqueous environment, the binding force of SFMA on titanium is significantly reduced due to hydrophilic interaction, making the coating magnetically controllable by an externally-used magnet but still stable in the absence of a magnet. The maximum working distance of the magnet can be calculated using magnetomechanical simulation in which the yielding magnetic traction force is strong enough to pull Fe3O4 nanoparticles off the surface. The pulling-off removes the biofilms that formed on the coating and enhances antibiotic killing both in vitro and in a rat sub-cutaneous implant model by up to 100 fold. This work contributes to the practical knowledge of magnetic propulsion for biofilm treatment.}, } @article {pmid38628638, year = {2024}, author = {Shariati, A and Noei, M and Askarinia, M and Khoshbayan, A and Farahani, A and Chegini, Z}, title = {Inhibitory effect of natural compounds on quorum sensing system in Pseudomonas aeruginosa: a helpful promise for managing biofilm community.}, journal = {Frontiers in pharmacology}, volume = {15}, number = {}, pages = {1350391}, pmid = {38628638}, issn = {1663-9812}, abstract = {Pseudomonas aeruginosa biofilm is a community of bacteria that adhere to live or non-living surfaces and are encapsulated by an extracellular polymeric substance. Unlike individual planktonic cells, biofilms possess a notable inherent resistance to sanitizers and antibiotics. Overcoming this resistance is a substantial barrier in the medical and food industries. Hence, while antibiotics are ineffective in eradicating P. aeruginosa biofilm, scientists have explored alternate strategies, including the utilization of natural compounds as a novel treatment option. To this end, curcumin, carvacrol, thymol, eugenol, cinnamaldehyde, coumarin, catechin, terpinene-4-ol, linalool, pinene, linoleic acid, saponin, and geraniol are the major natural compounds extensively utilized for the management of the P. aeruginosa biofilm community. Noteworthy, the exact interaction of natural compounds and the biofilm of this bacterium is not elucidated yet; however, the interference with the quorum sensing system and the inhibition of autoinducer production in P. aeruginosa are the main possible mechanisms. Noteworthy, the use of different drug platforms can overcome some drawbacks of natural compounds, such as insolubility in water, limited oral bioavailability, fast metabolism, and degradation. Additionally, drug platforms can deliver different antibiofilm agents simultaneously, which enhances the antibiofilm potential of natural compounds. This article explores many facets of utilizing natural compounds to inhibit and eradicate P. aeruginosa biofilms. It also examines the techniques and protocols employed to enhance the effectiveness of these compounds.}, } @article {pmid38626650, year = {2024}, author = {Si, B and Yang, Y and Naveed, M and Wang, F and Chan, MWH}, title = {Characterizations of biogenic selenium nanoparticles and their anti-biofilm potential against Streptococcus mutans ATCC 25175.}, journal = {Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS)}, volume = {84}, number = {}, pages = {127448}, doi = {10.1016/j.jtemb.2024.127448}, pmid = {38626650}, issn = {1878-3252}, abstract = {INTRODUCTION: S. mutans has been identified as the primary pathogenic bacterium in biofilm-mediated dental caries. The biogenic selenium nanoparticles (SeNPs) produced by L. plantarum KNF-5 were used in this study against S. mutans ATCC 25175.

OBJECTIVES: The aims of this study were: (1) the biosynthesis of SeNPs by L. plantarum KNF-5, (2) the characterization of SeNPs, (3) the investigation of the inhibitory effect of biogenic SeNPs against S. mutans ATCC 25175, and (4) the determination of the anti-biofilm potential of SeNPS against S. mutans ATCC 25175.

METHODOLOGY: 3 mL of the culture was added to 100 mL of MRS medium and incubated. After 4 h, Na2SeO3 solution (concentration 100 μg/mL) was added and incubated at 37 °C for 36 h. The color of the culture solution changed from brownish-yellow to reddish, indicating the formation of SeNPs. The characterization of SeNPs was confirmed by UV-Vis spectrophotometry, FTIR, SEM-EDS and a particle size analyzer. The antibacterial activity was determined by the disk diffusion method, the MIC by the micro-double dilution method, and the biofilm inhibitory potential by the crystal violet method and the MTT assay. The effect of SeNPs on S. mutans ATCC 25175 was determined using SEM and CLSM spectrometry techniques. The sulfate-anthrone method was used to analyze the effect of SeNPs on insoluble extracellular polysaccharides. The expression of genes in S. mutans ATCC 25175 was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR).

PREPARATION OF NANOPARTICLES: SeNPs produced by probiotic bacteria are considered a safe method. In this study, L. plantarum KNF-5 (probiotic strain) was used for the production of SeNPs.

RESULTS: The biogenic SeNPs were spherical and coated with proteins and polysaccharides and had a diameter of about 270 nm. The MIC of the SeNPs against S. mutans ATCC 25175 was 3.125 mg/mL. Biofilm growth was also significantly suppressed at this concentration. The expression of genes responsible for biofilm formation (GtfB, GtfC, BrpA and GbpB,) was reduced when S. mutans ATCC 25175 was treated with SeNPs.

CONCLUSION: It was concluded that the biogenic SeNPs produced by L. plantarum KNF-5 was highly effective to inhibit the growth of S. mutans ATCC 25175.

NOVELTY STATEMENT: The application of biogenic SeNPs, a natural anti-biofilm agent against S. mutans ATCC 25175. In the future, this study will provide a new option for the prevention and treatment of dental caries.}, } @article {pmid38625517, year = {2024}, author = {Piecuch, A and Cal, M and Ogórek, R}, title = {Adhesion and biofilm formation by two clinical isolates of Trichosporon Cutaneum in various environmental conditions.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {38625517}, issn = {1678-4405}, support = {2020/04/X/NZ9/00644//Narodowe Centrum Nauki/ ; }, abstract = {Trichosporon spp. is an emerging opportunistic pathogen and a common cause of both superficial and invasive infections. Although Trichosporon asahii is the most frequently isolated species, Trichosporon cutaneum is also widely observed, as it is the predominant agent in cases of white Piedra and onychomycosis. Trichosporon spp. is a known to produce biofilms, which serve as one of its virulence mechanisms, however, there is limited data available on biofilms formed by T. cutaneum. Thus, the aim of this study was to assess the adhesion and biofilm formation of two clinical isolates of T. cutaneum under various environmental conditions (including temperature, nutrient availability, and carbon source), as well as their tolerance to fluconazole. Adhesion was tested on common abiotic substrates (such as silicone, glass, and stainless steel), revealing that T. cutaneum readily adhered to all surfaces tested. CV staining was applied for the evaluation of the environment influence on biofilm efficiency and it was proved that the nutrient availability has a major impact. Additionaly, fluorescent staining was employed to visualize the morphology of T. cutaneum biofilm and its survival in the presence of fluconazole. Hyphae production was shown to play a role in elevated biofilm production in minimal medium and increased tolerance to fluconazole.}, } @article {pmid38625380, year = {2024}, author = {Hayatimehr, S and Mirkalantari, S and Amirmozafari, N and Jazi, FM and Moghadam, MT}, title = {Virulence Genes and Biofilm Formation Among Legionella pneumophila Isolates Collected from Hospital Water Sources.}, journal = {Current microbiology}, volume = {81}, number = {6}, pages = {141}, pmid = {38625380}, issn = {1432-0991}, mesh = {Humans ; *Legionella pneumophila/genetics ; Virulence/genetics ; Chlorine/pharmacology ; Iran ; *Legionella ; Biofilms ; Hospitals ; }, abstract = {Legionella pneumophila can be transmitted to people, especially immunocompromised patients, via hospital water pipe systems and cause severe pneumonia. The aim of our study was to investigate the presence of major virulence factor genes, ability of biofilms formation, and correlation between presence of Legionella isolates and temperature, pH, and residual chlorine of water. Hundred water samples were collected from nine hospitals in Tehran, Iran. Temperature, pH, and residual chlorine were determined during sampling. Different virulence genes and the ability to form biofilms were subsequently analyzed among the L. pneumophila isolates. Results showed that 12 (12%) samples were positive in culture method and all of the isolates were positive as L. pneumophila species (mip). A correlation was found between Legionella culture positivity and temperature and pH of water, but there was no significant correlation between residual chlorine of water samples and the presence of Legionella. The isolation of Legionella rate in summer and spring was higher than winter and autumn. Twelve (100%) isolates were positive for mip genes, 9 (75%) for dot genes, 8 (66.66%) for hsp, 6 (50%) for lvh, and 4 (33.33%) for rtx. All of the isolates displayed strong ability for biofilm production every three days. Two of these isolates (16.6%) displayed weak ability to form biofilm on the first day of incubation. This study revealed that water sources in hospitals were colonized by virulent Legionella and should be continuously monitored to avoid elevated concentrations of Legionella with visible biofilm formation.}, } @article {pmid38625018, year = {2024}, author = {Ma, Z and Sun, Y and Liu, Y and Jiao, J and Li, N and Zuo, Y and Li, Z and Li, Y and Cai, X and Meng, Q and Qiao, J}, title = {STM1863, a Member of the DUFs Protein Family, Is Involved in Environmental Adaptation, Biofilm Formation, and Virulence in Salmonella Typhimurium.}, journal = {Foodborne pathogens and disease}, volume = {}, number = {}, pages = {}, doi = {10.1089/fpd.2023.0139}, pmid = {38625018}, issn = {1556-7125}, abstract = {Salmonella Typhimurium (STM) is an important zoonotic Gram-negative pathogen that can cause infection in a variety of livestock and poultry. Meanwhile, as an important foodborne pathogen, the bacterium can survive in various stressful environments and transmits through the fecal-oral route, posing a serious threat to global food safety. To investigate the roles of STM1863, a member of the DUFs protein family, involved in STM environmental adaptation, biofilm formation, and virulence. We analyzed the molecular characteristics of the protein encoded by STM1863 gene and examined intra- and extracellular expression levels of STM1863 gene in mouse macrophages. Furthermore, we constructed STM1863 gene deletion and complementation strains and determined its environmental adaptation under stressful conditions such as acid, alkali, high salt, bile salt, and oxidation. And the capacity of biofilm formation and pathogenicity of those strains were analyzed and compared. In addition, the interaction between the promoter of STM1863 gene and RcsB protein was analyzed using DNA gel electrophoresis migration assay (electrophoretic mobility shift assay [EMSA]). The experiments revealed that acid adaptability and biofilm formation ability of STM1863 gene deletion strain were significantly weakened compared with the parental and complementary strains. Moreover, the adhesion and invasion ability of STM1863 deletion strain to mouse macrophages was significantly decreased, while the median lethal dose (LD50) increased by 2.148-fold compared with the parental strain. In addition, EMSA confirmed that RcsB protein could bind to the promoter sequence of STM1863 gene, suggesting that the expression of STM1863 gene might be modulated by RcsB. The present study demonstrated for the first time that STM1863, a member of the DUFs protein family, is involved in the modulation of environmental adaptation, biofilm formation, and virulence.}, } @article {pmid38624207, year = {2024}, author = {Banerjee, A and Kang, C-Y and An, M and Koff, BB and Sunder, S and Kumar, A and Tenuta, LMA and Stockbridge, RB}, title = {Fluoride export is required for the competitive fitness of pathogenic microorganisms in dental biofilm models.}, journal = {mBio}, volume = {}, number = {}, pages = {e0018424}, doi = {10.1128/mbio.00184-24}, pmid = {38624207}, issn = {2150-7511}, abstract = {UNLABELLED: Microorganisms resist fluoride toxicity using fluoride export proteins from one of several different molecular families. Cariogenic species Streptococcus mutans and Candida albicans extrude intracellular fluoride using a CLC[F] F[-]/H[+] antiporter and FEX fluoride channel, respectively, whereas oral commensal eubacteria, such as Streptococcus gordonii, export fluoride using a Fluc fluoride channel. In this work, we examine how genetic knockout of fluoride export impacts pathogen fitness in single-species and three-species dental biofilm models. For biofilms generated using S. mutans with the genetic knockout of the CLC[F] transporter, exposure to low fluoride concentrations decreased S. mutans counts, synergistically reduced the populations of C. albicans, increased the relative proportion of oral commensal S. gordonii, and reduced properties associated with biofilm pathogenicity, including acid production and hydroxyapatite dissolution. Biofilms prepared with C. albicans with genetic knockout of the FEX channel also exhibited reduced fitness in the presence of fluoride but to a lesser degree. Imaging studies indicate that S. mutans is highly sensitive to fluoride, with the knockout strain undergoing complete lysis when exposed to low fluoride for a moderate amount of time. Biochemical purification of the S. mutans CLC[F] transporter and functional reconstitution establishes that the functional protein is a dimer encoded by a single gene. Together, these findings suggest that fluoride export by oral pathogens can be targeted by specific inhibitors to restore biofilm symbiosis in dental biofilms and that S. mutans is especially susceptible to fluoride toxicity.

IMPORTANCE: Dental caries is a globally prevalent condition that occurs when pathogenic species, including Streptococcus mutans and Candida albicans, outcompete beneficial species, such as Streptococcus gordonii, in the dental biofilm. Fluoride is routinely used in oral hygiene to prevent dental caries. Fluoride also has antimicrobial properties, although most microbes possess fluoride exporters to resist its toxicity. This work shows that sensitization of cariogenic species S. mutans and C. albicans to fluoride by genetic knockout of fluoride exporters alters the microbial composition and pathogenic properties of dental biofilms. These results suggest that the development of drugs that inhibit fluoride exporters could potentiate the anticaries effect of fluoride in over-the-counter products like toothpaste and mouth rinses. This is a novel strategy to treat dental caries.}, } @article {pmid38622845, year = {2024}, author = {Priyadarshini, E and Kumar, R and Balakrishnan, K and Pandit, S and Kumar, R and Jha, NK and Gupta, PK}, title = {Biofilm Inhibition on Medical Devices and Implants Using Carbon Dots: An Updated Review.}, journal = {ACS applied bio materials}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsabm.4c00024}, pmid = {38622845}, issn = {2576-6422}, abstract = {Biofilms are an intricate community of microbes that colonize solid surfaces, communicating via a quorum-sensing mechanism. These microbial aggregates secrete exopolysaccharides facilitating adhesion and conferring resistance to drugs and antimicrobial agents. The escalating global concern over biofilm-related infections on medical devices underscores the severe threat to human health. Carbon dots (CDs) have emerged as a promising substrate to combat microbes and disrupt biofilm matrices. Their numerous advantages such as facile surface functionalization and specific antimicrobial properties, position them as innovative anti-biofilm agents. Due to their minuscule size, CDs can penetrate microbial cells, inhibiting growth via cytoplasmic leakage, reactive oxygen species (ROS) generation, and genetic material fragmentation. Research has demonstrated the efficacy of CDs in inhibiting biofilms formed by key pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Consequently, the development of CD-based coatings and hydrogels holds promise for eradicating biofilm formation, thereby enhancing treatment efficacy, reducing clinical expenses, and minimizing the need for implant revision surgeries. This review provides insights into the mechanisms of biofilm formation on implants, surveys major biofilm-forming pathogens and associated infections, and specifically highlights the anti-biofilm properties of CDs emphasizing their potential as coatings on medical implants.}, } @article {pmid38621525, year = {2024}, author = {Sampaio, C and Méndez, DAC and Buzalaf, MAR and Pessan, JP and Cruvinel, T}, title = {Arginine and sodium fluoride affect the microbial composition and reduce biofilm metabolism and enamel mineral loss in an oral microcosm model.}, journal = {Journal of dentistry}, volume = {}, number = {}, pages = {104997}, doi = {10.1016/j.jdent.2024.104997}, pmid = {38621525}, issn = {1879-176X}, abstract = {OBJECTIVE: To assess the effects of arginine, with or without sodium fluoride (NaF; 1,450 ppm), on saliva-derived microcosm biofilms and enamel demineralization.

METHODS: Saliva-derived biofilms were grown on bovine enamel blocks in 0.2% sucrose-containing modified McBain medium, according to six experimental groups: control (McBain 0.2%); 2.5% arginine; 8% arginine; NaF; 2.5% arginine with NaF; and 8% arginine with NaF. After 5 days of growth, biofilm viability was assessed by colony-forming units counting, laser scanning confocal microscopy was used to determine biofilm vitality and extracellular polysaccharide (EPS) production, while biofilm metabolism was evaluated using the resazurin assay and lactic acid quantification. Demineralization was evaluated by measuring pH in the culture medium and calcium release. Data were analyzed by Kruskal-Wallis' and Dunn's tests (p<0.05).

RESULTS: 8% arginine with NaF showed the strongest reduction in total streptococci and total microorganism counts, with no significant difference compared to arginine without NaF. Neither 2.5% arginine alone nor NaF alone significantly reduced microbial counts compared to the control, although in combination, a reduction in all microbial groups was observed. Similar trends were found for biofilm vitality and EPS, and calcium released to the growth medium.

CONCLUSIONS: 8% Arginine, with or without NaF, exhibited the strongest antimicrobial activity and reduced enamel calcium loss. Also, NaF enhanced the effects of 2.5% arginine, yielding similar results to 8% arginine for most parameters analyzed.

CLINICAL SIGNIFICANCE: The results provided further evidence on how arginine, with or without NaF, affects oral microcosm biofilms and enamel mineral loss.}, } @article {pmid38621382, year = {2024}, author = {Chaudhary, K and Agrahari, B and Biswas, B and Chatterjee, N and Chaudhary, A and Kumar, A and Sonkar, H and Dewan, S and Saxena, D and Akhir, A and Malhotra, N and Chopra, S and Misra, S and Matheswaran, S and Singh, RG}, title = {Pyridine-2,6-dicarboxamide proligands and their Cu(II)/Zn(II) complexes Targeting Staphylococcus Aureus for the Attenuation of In-vivo Dental Biofilm.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2400378}, doi = {10.1002/adhm.202400378}, pmid = {38621382}, issn = {2192-2659}, abstract = {In the pursuit to combat stubborn bacterial infections, particularly those stemming from gram-positive bacteria, our study is an attempt to craft a precision-driven platform characterized by unparalleled selectivity, specificity, and synergistic antimicrobial mechanisms. Leveraging remarkable potential of metalloantibiotics in antimicrobial applications, herein, we rationally design, synthesize, and characterize a new library of Pyridine-2,6-dicarboxamide ligands and their corresponding transition metal Cu(II)/Zn(II) complexes. The lead compound L[11] demonstrate robust antibacterial properties against Staphylococcus aureus (MIC = 2-16 µg/mL), methicillin and vancomycin-resistant S. aureus (MIC = 2-4 µg/mL) and exhibit superior antibacterial activity when compared to FDA-approved vancomycin, the drug of last resort. Additionally, the compound exhibited notable antimicrobial efficacy against resistant enterococcus strains (MIC = 2-8 µg/mL). To unravel mechanistic profile, advanced imaging techniques including SEM and AFM were harnessed, collectively suggesting a mechanistic pathway involving cell wall disruption. Live/dead fluorescence studies further confirm efficacy of L[11] and its complexes against S. aureus membranes. Our translational exploration extends to a rat model, indicating promising In-vivo therapeutic potential. Thus, our comprehensive research initiative has capabilities to transcends the confines of our laboratory, heralding a pivotal step toward combatting antibiotic-resistant pathogens and advancing the frontiers of metalloantibiotics based therapy with a profound clinical implication. This article is protected by copyright. All rights reserved.}, } @article {pmid38621130, year = {2024}, author = {Postek, W and Staśkiewicz, K and Lilja, E and Wacław, B}, title = {Substrate geometry affects population dynamics in a bacterial biofilm.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {121}, number = {17}, pages = {e2315361121}, doi = {10.1073/pnas.2315361121}, pmid = {38621130}, issn = {1091-6490}, support = {UMO-2019/02/H/NZ6/00003//Narodowe Centrum Nauki (NCN)/ ; PPN/PPO/2019/1/ 00030 /U/0001//Narodowa Agencja Wymiany Akademickiej (NAWA)/ ; PPN/BEK/2020/1/00333/U/00001//Narodowa Agencja Wymiany Akademickiej (NAWA)/ ; 069.2021//Fundacja na rzecz Nauki Polskiej (FNP)/ ; }, abstract = {Biofilms inhabit a range of environments, such as dental plaques or soil micropores, often characterized by noneven surfaces. However, the impact of surface irregularities on the population dynamics of biofilms remains elusive, as most experiments are conducted on flat surfaces. Here, we show that the shape of the surface on which a biofilm grows influences genetic drift and selection within the biofilm. We culture Escherichia coli biofilms in microwells with a corrugated bottom surface and observe the emergence of clonal sectors whose size corresponds to that of the corrugations, despite no physical barrier separating different areas of the biofilm. The sectors are remarkably stable and do not invade each other; we attribute this stability to the characteristics of the velocity field within the biofilm, which hinders mixing and clonal expansion. A microscopically detailed computer model fully reproduces these findings and highlights the role of mechanical interactions such as adhesion and friction in microbial evolution. The model also predicts clonal expansion to be limited even for clones with a significant growth advantage-a finding which we confirm experimentally using a mixture of antibiotic-sensitive and antibiotic-resistant mutants in the presence of sublethal concentrations of the antibiotic rifampicin. The strong suppression of selection contrasts sharply with the behavior seen in range expansion experiments in bacterial colonies grown on agar. Our results show that biofilm population dynamics can be affected by patterning the surface and demonstrate how a better understanding of the physics of bacterial growth can be used to control microbial evolution.}, } @article {pmid38619862, year = {2024}, author = {Tian, Y and Zhong, F and Shang, N and Yu, H and Mao, D and Huang, X}, title = {Maize root exudates promote Bacillus sp. Za detoxification of diphenyl ether herbicides by enhancing colonization and biofilm formation.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {}, number = {}, pages = {}, doi = {10.1094/MPMI-02-24-0020-R}, pmid = {38619862}, issn = {0894-0282}, abstract = {Diphenyl ether herbicides are extensively utilized in agricultural systems, but their residues threaten the health of sensitive rotation crops. Functional microbial strains can degrade diphenyl ether herbicides in the rhizosphere of crops, facilitating the restoration of a healthy agricultural environment. However, the interplay between microorganisms and plants in diphenyl ether herbicides degradation remains unclear. Thus, the herbicide-degrading strain Bacillus sp. Za and the sensitive crop, maize, were employed to uncover the interaction mechanism. The degradation of diphenyl ether herbicides by strain Bacillus sp. Za was promoted by root exudates. The strain induced root exudates re-secretion in diphenyl ether herbicide-polluted maize. We further showed that root exudates enhanced the rhizosphere colonization and the biofilm biomass of strain Za, augmenting its capacity to degrade diphenyl ether herbicide. Root exudates regulated gene fliZ, pivotal in biofilm formation. Wild-type strain Za significantly reduced herbicide toxicity to maize compared to the ZaΔfliZ mutant. Moreover, root exudates promoted strain Za growth and chemotaxis, which was related to biofilm formation. This mutualistic relationship between the microorganisms and the plants demonstrates the significance of plant-microbe interactions in shaping diphenyl ether herbicide degradation in rhizosphere soils.}, } @article {pmid38619794, year = {2024}, author = {Van Holm, W and Zayed, N and Lauwens, K and Saghi, M and Axelsson, J and Aktan, MK and Braem, A and Simoens, K and Vanbrabant, L and Proost, P and Van Holm, B and Maes, P and Boon, N and Bernaerts, K and Teughels, W}, title = {Oral Biofilm Composition, Dissemination to Keratinocytes, and Inflammatory Attenuation Depend on Probiotic and Synbiotic Strain Specificity.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {38619794}, issn = {1867-1314}, support = {C24/17/086//KU Leuven/ ; C16/17/010//KU Leuven/ ; C16/17/010//KU Leuven/ ; C24/17/086//KU Leuven/ ; G091218N//Fonds Wetenschappelijk Onderzoek/ ; G091218N//Fonds Wetenschappelijk Onderzoek/ ; }, abstract = {Several inflammatory diseases are characterized by a disruption in the equilibrium between the host and its microbiome. Due to the increase in resistance, the use of antibiotics for the widespread, nonspecific killing of microorganisms is at risk. Pro-microbial approaches focused on stimulating or introducing beneficial species antagonistic toward pathobionts may be a viable alternative for restoring the host-microbiome equilibrium. Unfortunately, not all potential probiotic or synbiotic species and even subspecies (to strain level) are equally effective for the designated pathology, leading to conflicting accounts of their efficacy. To assess the extent of these species- and strain-specific effects, 13 probiotic candidates were evaluated for their probiotic and synbiotic potential with glycerol on in vitro oral biofilms, dissemination from biofilms to keratinocytes, and anti-inflammatory activity. Species- and strain-specific effects and efficacies were observed in how they functioned as probiotics or synbiotics by influencing oral pathobionts and commensals within biofilms and affected the dissemination of pathobionts to keratinocytes, ranging from ineffective strains to strains that reduced pathobionts by 3 + log. In addition, a minority of the candidates exhibited the ability to mitigate the inflammatory response of LPS-stimulated monocytes. For a comprehensive assessment of probiotic therapy for oral health, a judicious selection of fully characterized probiotic strains that are specifically tailored to the designated pathology is required. This approach aims to challenge the prevailing perception of probiotics, shifting the focus away from "form over function." Rather than using unproven, hypothetical probiotic strains from known genera or species, one should choose strains that are actually functional in resolving the desired pathology before labelling them probiotics.}, } @article {pmid38618300, year = {2024}, author = {Berk Ergun, Ş and Has, EG and Akçelik, N and Akçelik, M}, title = {Characteristics of Bacterial Biofilm Formation in Nasolacrimal Silicone Tubes Post-dacryocystorhinostomy.}, journal = {Cureus}, volume = {16}, number = {3}, pages = {e56112}, pmid = {38618300}, issn = {2168-8184}, abstract = {PURPOSE: To examine the biofilm formation characteristics of bacteria identified at the genus level in samples obtained from silicone tubes after dacryocystorhinostomy surgery.

METHODS: In the study involving consecutive patients who underwent dacryocystorhinostomy surgery at Ankara Bilkent City Hospital and whose silicone tubes were removed six months after surgery, between January 2023 and May 2023; the tubes were placed in glycerol-PBS (phosphate buffered saline) solution and cultured on descriptive selective media at the genus level. The biofilm-forming properties of the obtained isolates were examined in solid-air and liquid-air interphases. Salmonella Typhimurium ATCC SL1344 strain was used as the control bacterium.

RESULTS: As a result of the analysis of the samples taken from the patients, Pseudomonas spp. was identified in three of the samples, Staphylococcus spp. in five of the samples, and Streptococcus spp. in one of the samples. Among these samples, except for the bacteria identified in samples one and five, the rest were found to be strong biofilm producers. In all strong biofilm producers, the maximum biofilm production time was determined as 72 h and the incubation temperature was 37°C. The presence of cellulose and amyloid proteins in biofilm matrix structures is identified. Swimming and swarming motilities were observed in all bacterial samples.

CONCLUSION: Since biofilms are considered potential factors in the pathogenesis of infectious and inflammatory diseases, they are a subject that needs to be thoroughly investigated. In our study, although there were no clinical infections in any of the patients, biofilm formation was detected in the patient samples. The fact that the bacteria exhibited moderate to strong biofilm formation characteristics suggests that these microorganisms could be persistent infectious agents.}, } @article {pmid38616595, year = {2024}, author = {Shah, PK and Bhandari, N and Tamang, B and Joshi, RD}, title = {Antibiotic Susceptibility and Biofilm Production among Coagulase Negative Staphylococci Isolated from Clinical Samples at Tertiary Care Hospital.}, journal = {Journal of Nepal Health Research Council}, volume = {21}, number = {4}, pages = {636-641}, doi = {10.33314/jnhrc.v21i4.4894}, pmid = {38616595}, issn = {1999-6217}, abstract = {BACKGROUND: Coagulase Negative Staphylococci have been widely associated with medical device implant treatment and immune-compromised patients. Despite having increasing interest in Coagulase Negative Staphylococci, few studies from Nepal have reported the association of these organisms with urinary tract infections, conjunctivitis, high vaginal swabs, and cerebrospinal fluid. This study was carried out to determine antibiotic susceptibility pattern and biofilm production among Coagulase Negative Staphylococci isolated from clinical samples at tertiary care hospital.

METHODS: This study was a hospital based cross-sectional study in which 3690 clinical samples were included. Isolation and identification of isolates was done following standard microbiological protocol. Coagulase Negative Staphylococci were identified phenotypically on the basis of gram staining, slide and tube coagulase test and by various sugar fermentation tests. Antibiotic susceptibility test was done following Kirby Bauer disk diffusion method (Clinical and Laboratory Standards Institute 2020). Biofilm production was determined by Tissue Culture Plate technique.

RESULTS: A total of 113 isolates of Coagulase Negative Staphylococci were detected. Among them S. epidermidis (45.1%), S. saprophyticus (23.9%), S. haemolyticus (16.8%), S. hominis (5.3%), S. capitis (2.7%), -----S. cohini (1.8%), S. lugdunensis (1.8%) and S. sciuri (2.7%) were identified phenotypically. All isolates were found to be resistant against Ampicillin and 111 (98.2%) were sensitive against Linezolid.23.9% of CoNS were strong biofilm producers, 19.5% moderate and 56.6 % were non/weak biofilm producers.

CONCLUSIONS: It requires susceptibility test for prescribing antibiotics against Coagulase Negative Staphylococci in hospital and the misuse of antibiotics should be prevented.}, } @article {pmid38616221, year = {2024}, author = {Srivastava, A and Verma, N and Kumar, V and Apoorva, P and Agarwal, V}, title = {Biofilm inhibition/eradication: exploring strategies and confronting challenges in combatting biofilm.}, journal = {Archives of microbiology}, volume = {206}, number = {5}, pages = {212}, pmid = {38616221}, issn = {1432-072X}, abstract = {Biofilms are complex communities of microorganisms enclosed in a self-produced extracellular matrix, posing a significant threat to different sectors, including healthcare and industry. This review provides an overview of the challenges faced due to biofilm formation and different novel strategies that can combat biofilm formation. Bacteria inside the biofilm exhibit increased resistance against different antimicrobial agents, including conventional antibiotics, which can lead to severe problems in livestock and animals, including humans. In addition, biofilm formation also imposes heavy economic pressure on industries. Hence it becomes necessary to explore newer alternatives to eradicate biofilms effectively without applying selection pressure on the bacteria. Excessive usage of antibiotics may also lead to an increase in the number of resistant strains as bacteria employ an advanced antimicrobial resistance mechanism. This review provides insight into multifaceted technologies like quorum sensing inhibition, enzymes, antimicrobial peptides, bacteriophage, phytocompounds, and nanotechnology to neutralize biofilms without developing antimicrobial resistance (AMR). Furthermore, it will pave the way for developing newer therapeutic agents to deal with biofilms more efficiently.}, } @article {pmid38615826, year = {2024}, author = {Pereira, ACC and Aguiar, APS and Barbosa, VL and Régia, JR and Miyazima, EM and Araujo, LMP and Dantas, LO and Mayer, MPA and Andrade, FB and Karygianni, L and Pinheiro, ET}, title = {Enhancing Antibiotic Efficacy in Regenerative Endodontics by Improving Biofilm Susceptibility.}, journal = {Journal of endodontics}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.joen.2024.04.004}, pmid = {38615826}, issn = {1878-3554}, abstract = {INTRODUCTION: Various strategies have been researched to enhance the susceptibility of biofilms, given their tolerance to antibiotics. This study evaluated the effect of the antimicrobial peptide nisin in association with antibiotics used in regenerative endodontics, exploring different treatment times and biofilm growth conditions.

METHODS: A mixture of ten bacterial species was cultivated on dentin specimens anaerobically for 21 days. Biofilms were treated with 1 mL of high-purity nisin Z (nisin ZP, 200 μg/mL) and a triple antibiotic mixture (TAP: ciprofloxacin + metronidazole + minocycline, 5mg/ mL), alone or in combination. The effectiveness of antimicrobial agents was assessed after one and seven days. During the 7-day period, biofilms were treated under two conditions: a single dose in a nutrient-depleted setting (i.e., no replenishment of growth medium) and multiple doses in a nutrient-rich environment (i.e., renewal of medium and antimicrobial agents every 48 h). After treatments, biofilm cells were dispersed, and total colony-forming units were counted.

RESULTS: After 1d-treatment, nisin ZP + TAP resulted in 2-log cell reduction compared to TAP alone (P < .05). After 7 d-treatment with a single dose, nisin ZP + TAP and TAP reduced bacteria to non-culturable levels (P < .05), whereas repeated antimicrobial doses did not eliminate bacteria in a nutrient-rich environment. No bacterial reduction was observed with nisin ZP alone in any treatment time.

CONCLUSIONS: The additional use of nisin improved the TAP activity only after a short exposure time. Longer exposure to TAP or nisin + TAP in a nutrient-deprived environment effectively eliminated biofilms.}, } @article {pmid38614413, year = {2024}, author = {Ali, A and Riaz, S}, title = {Emerging threats of high biofilm formation and antibiotic resistance in clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates from Pakistan.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {}, number = {}, pages = {105592}, doi = {10.1016/j.meegid.2024.105592}, pmid = {38614413}, issn = {1567-7257}, abstract = {OBJECTIVES: This multicenter study, conducted from a One Health perspective, aimed to comprehensively examine the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) infections and their biofilm-forming capabilities in Pakistan. Phylogenetic analysis of the study isolates was also performed.

METHODS: A total of 150 MRSA isolates were screened from various clinical samples using Cefoxitin antibiotic discs. Genotypic confirmation was conducted through mecA, S. aureus-specific nuc, and 16S rRNA genes. Biofilm formation was assessed using Congo red agar (CRA) and slime layer quantification methods. The intercellular adhesion (ica) operon genes, specifically icaA and icaD, were detected. Phylogenetic analysis utilized the 16S rRNA sequences. Statistical associations between various parameters were determined using chi-square analysis.

RESULTS: The presence of the mecA gene was observed in 131 out of 150 isolates (87.3%). CRA identified 28% and 40% of isolates as strong and moderate biofilm producers, respectively, while 9.3% were classified as non-biofilm producers. The slime layer assay exhibited higher sensitivity, classifying only 4.7% of isolates as non-biofilm producers. Biofilm-forming genes icaA and icaD were detected in 85.3% and 86.7% of the isolates, respectively. Antibiotic resistance was more prevalent among biofilm-forming isolates, particularly against ciprofloxacin, levofloxacin, erythromycin, trimethoprim-sulfamethoxazole, and fosfomycin. Ceftaroline demonstrated efficacy irrespective of biofilm-forming abilities. Conversely, non-biofilm producers exhibited complete susceptibility to clarithromycin and tigecycline.

CONCLUSIONS: Clinical MRSA strains exhibit a substantial potential for biofilm formation, contributing to a resistant phenotype. Routine antibiotic testing in clinical settings that overlook the biofilm aspect may lead to the failure of empiric antibiotic therapy.}, } @article {pmid38614333, year = {2024}, author = {Buakaew, T and Ratanatamskul, C}, title = {Unveiling the influence of microaeration and sludge recirculation on enhancement of pharmaceutical removal and microbial community change of the novel anaerobic baffled biofilm - membrane bioreactor in treating building wastewater.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {172420}, doi = {10.1016/j.scitotenv.2024.172420}, pmid = {38614333}, issn = {1879-1026}, abstract = {This research aims to conduct a comparative investigation of the role played by microaeration and sludge recirculation in the novel anaerobic baffled biofilm-membrane bioreactor (AnBB-MBR) for enhancing pharmaceutical removal from building wastewater. Three AnBB-MBRs - R1: AnBB-MBR, R2: AnBB-MBR with microaeration and R3: AnBB-MBR with microaeration and sludge recirculation - were operated simultaneously to remove Ciprofloxacin (CIP), Caffeine (CAF), Sulfamethoxazole (SMX) and Diclofenac (DCF) from real building wastewater at the hydraulic retention time (HRT) of 30 h for 115 days. From the removal profiles of the targeted pharmaceuticals in the AnBB-MBRs, it was found that the fixed-film compartment (C1) could significantly reduce the targeted pharmaceuticals. The remaining pharmaceuticals were further removed with the microaeration compartment. R2 exhibited the utmost removal efficiency for CIP (78.0 %) and DCF (40.8 %), while SMX was removed most successfully by R3 (microaeration with sludge recirculation) at 91.3 %, followed by microaeration in R2 (88.5 %). For CAF, it was easily removed by all AnBB-MBR systems (>90 %). The removal mechanisms indicate that the microaeration in R2 facilitated the adsorption of CIP onto microaerobic biomass, while the enhanced biodegradation of CAF, SMX and DCF was confirmed by batch biotransformation kinetics and the adsorption isotherms of the targeted pharmaceuticals. The microbial groups involved in biodegradation of the targeted compounds under microaeration were identified as nitrogen removal microbials (Nitrosomonas, Nitrospira, Thiobacillus, and Denitratisoma) and methanotrophs (Methylosarcina, Methylocaldum, and Methylocystis). Overall, explication of the integration of AnBB-MBR with microaeration (R2) confirmed it as a prospective technology for pharmaceutical removal from building wastewater due to its energy-efficient approach characterized by minimal aeration supply.}, } @article {pmid38613837, year = {2024}, author = {Quispe Haro, JJ and Chen, F and Los, R and Shi, S and Sun, W and Chen, Y and Idema, T and Wegner, SV}, title = {Optogenetic Control of Bacterial Cell-Cell Adhesion Dynamics: Unraveling the Influence on Biofilm Architecture and Functionality.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2310079}, doi = {10.1002/advs.202310079}, pmid = {38613837}, issn = {2198-3844}, support = {DFG WE 5745/2-2//Deutsche Forschungsgemeinschaft/ ; 22208157//National Natural Science Foundation of China/ ; }, abstract = {The transition of bacteria from an individualistic to a biofilm lifestyle profoundly alters their biology. During biofilm development, the bacterial cell-cell adhesions are a major determinant of initial microcolonies, which serve as kernels for the subsequent microscopic and mesoscopic structure of the biofilm, and determine the resulting functionality. In this study, the significance of bacterial cell-cell adhesion dynamics on bacterial aggregation and biofilm maturation is elucidated. Using photoswitchable adhesins between bacteria, modifying the dynamics of bacterial cell-cell adhesions with periodic dark-light cycles is systematic. Dynamic cell-cell adhesions with liquid-like behavior improve bacterial aggregation and produce more compact microcolonies than static adhesions with solid-like behavior in both experiments and individual-based simulations. Consequently, dynamic cell-cell adhesions give rise to earlier quorum sensing activation, better intermixing of different bacterial populations, improved biofilm maturation, changes in the growth of cocultures, and higher yields in fermentation. The here presented approach of tuning bacterial cell-cell adhesion dynamics opens the door for regulating the structure and function of biofilms and cocultures with potential biotechnological applications.}, } @article {pmid38613443, year = {2024}, author = {Hajimohammadi, S and Momtaz, H and Tajbakhsh, E}, title = {Fabrication and antimicrobial properties of novel meropenem-honey encapsulated chitosan nanoparticles against multiresistant and biofilm-forming Staphylococcus aureus as a new antimicrobial agent.}, journal = {Veterinary medicine and science}, volume = {10}, number = {3}, pages = {e1440}, doi = {10.1002/vms3.1440}, pmid = {38613443}, issn = {2053-1095}, support = {//Islamic Azad University, Shahrekord Branch/ ; }, abstract = {BACKGROUND: Honey exhibits a broad spectrum of antibacterial activity against Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) ones. Chitosan (Cs) is a mucoadhesive polymer that also has antibacterial properties. Special attention has been paid to the design of polymeric nanoparticles (NPs) as new nano drug delivery systems to overcome bacterial resistance and its problems.

OBJECTIVES: The aim of the present study is to synthesize Cs-meropenem NPs with/without honey as an antibiofilm and antibacterial agent to inhibit Staphylococcus aureus.

METHODS: This study synthesized meropenem and honey-loaded Cs nanogels and subsequently characterized them by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), and DLS-zeta potential. Using the broth microdilution and crystal violet assays, the antibacterial and antibiofilm activity of meropenem and honey-loaded Cs nanogel, free meropenem, free honey, and free Cs NPs were investigated in vitro against MRSA strains. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) was also used to test the cytotoxicity of several Cs-NPs compound against the HEK-293 regular cell line.

RESULTS: The average size of meropenem and honey-Cs-NPs was reported to be 119.885 nm, and encapsulation efficiency was 88.33 ± 0.97 with stability up to 60 days at 4°C. The NPs showed enhanced antibiofilm efficacy against S. aureus at sub-minimum inhibitory concentrations. Additionally, the cytotoxicity of meropenem and honey-encapsulated Cs against the HEK-293 normal cell line was insignificant.

CONCLUSIONS: Our findings suggested that meropenem and honey-Cs-NPs might be potential antibacterial and antibiofilm materials.}, } @article {pmid38612793, year = {2024}, author = {Donati, L and Casagrande Pierantoni, D and Conti, A and Calzoni, E and Corte, L and Santi, C and Rosati, O and Cardinali, G and Emiliani, C}, title = {Water Extracts from Industrial Hemp Waste Inhibit the Adhesion and Development of Candida Biofilm and Showed Antioxidant Activity on HT-29 Colon Cancer Cells.}, journal = {International journal of molecular sciences}, volume = {25}, number = {7}, pages = {}, doi = {10.3390/ijms25073979}, pmid = {38612793}, issn = {1422-0067}, support = {J91B21003350006//Italian Ministry of University and Research (MIUR)/ ; }, abstract = {The evolution of regulatory perspectives regarding the health and nutritional properties of industrial hemp-based products (Cannabis sativa L.) has pushed research to focus on the development of new methods for both the extraction and formulation of the bioactive compounds present in hemp extracts. While the psychoactive and medicinal properties of hemp-derived cannabinoid extracts are well known, much less has been investigated on the functional and antimicrobial properties of hemp extracts. Within the hemp value chain, various agricultural wastes and by-products are generated. These materials can be valorised through eco-innovations, ultimately promoting sustainable economic development. In this study, we explored the use of waste from industrial light cannabis production for the extraction of bioactive compounds without the addition of chemicals. The five extracts obtained were tested for their antimicrobial activity on both planktonic and sessile cells of pathogenic strains of the Candida albicans, Candida parapsilosis, and Candida tropicalis species and for their antioxidant activity on HT-29 colon cancer cells under oxidative stress. Our results demonstrated that these extracts display interesting properties both as antioxidants and in hindering the development of fungal biofilm, paving the way for further investigations into the sustainable valorisation of hemp waste for different biomedical applications.}, } @article {pmid38612411, year = {2024}, author = {Chen, Y and Gao, Y and Li, Y and Yin, J}, title = {Anti-Biofilm Activity of Assamsaponin A, Theasaponin E1, and Theasaponin E2 against Candida albicans.}, journal = {International journal of molecular sciences}, volume = {25}, number = {7}, pages = {}, doi = {10.3390/ijms25073599}, pmid = {38612411}, issn = {1422-0067}, support = {CARS-19//China Agriculture Research System of MOF and MARA/ ; CAAS-ASTIP-TRI//the Innovation Project for Chinese Academy of Agricultural Sciences/ ; }, abstract = {Biofilm formation plays a crucial role in the pathogenesis of Candida albicans and is significantly associated with resistance to antifungal agents. Tea seed saponins, a class of non-ionic triterpenes, have been proven to have fungicidal effects on planktonic C. albicans. However, their anti-biofilm activity and mechanism of action against C. albicans remain unclear. In this study, the effects of three Camellia sinensis seed saponin monomers, namely, theasaponin E1 (TE1), theasaponin E2 (TE2), and assamsaponin A (ASA), on the metabolism, biofilm development, and expression of the virulence genes of C. albicans were evaluated. The results of the XTT reduction assay and crystal violet (CV) staining assay demonstrated that tea seed saponin monomers concentration-dependently suppressed the adhesion and biofilm formation of C. albicans and were able to eradicate mature biofilms. The compounds were in the following order in terms of their inhibitory effects: ASA > TE1 > TE2. The mechanisms were associated with reductions in multiple crucial virulence factors, including cell surface hydrophobicity (CSH), adhesion ability, hyphal morphology conversion, and phospholipase activity. It was further demonstrated through qRT-PCR analysis that the anti-biofilm activity of ASA and TE1 against C. albicans was attributed to the inhibition of RAS1 activation, which consequently suppressed the cAMP-PKA and MAPK signaling pathways. Conversely, TE2 appeared to regulate the morphological turnover and hyphal growth of C. albicans via a pathway that was independent of RAS1. These findings suggest that tea seed saponin monomers are promising innovative agents against C. albicans.}, } @article {pmid38612117, year = {2024}, author = {Santosaningsih, D and Mulyastuti, Y and Poejiani, S and Putri, RF and Dewi, L and Arifani, H and Ni'mah, YL and Baktir, A}, title = {The Biofilm Inhibition Properties of Glucosamine Gold Nanoparticles in Combination with Meropenem against Pseudomonas aeruginosa on the Endotracheal Tube: A Model of Biofilm-Related Ventilator-Associated Pneumonia.}, journal = {Materials (Basel, Switzerland)}, volume = {17}, number = {7}, pages = {}, doi = {10.3390/ma17071604}, pmid = {38612117}, issn = {1996-1944}, support = {801.12/UN10.C10/TU/2023//University of Brawijaya/ ; }, abstract = {Biofilm-related infections play a significant role in the development and persistence of ventilator-associated pneumonia. Pseudomonas aeruginosa (P. aeruginosa) frequently causes biofilm-related infections associated with ventilator tubing. Glucosamine gold nanoparticles (AuNPs) may exhibit antibiofilm properties; however, more studies, including combinatorial therapy with antibiotics, are needed to explore their potential applications in clinical settings. This study aims to investigate the biofilm inhibition properties of glucosamine AuNPs in combination with meropenem against P. aeruginosa ATCC 9027 on the endotracheal tube. A biofilm inhibition assay of glucosamine AuNPs at 0.02 mg/mL, both singly and in combination with meropenem at 1 mg/mL, was carried out against P. aeruginosa ATCC 9027 on an endotracheal tube using the tissue culture plate method. Scanning electron microscopy was performed for visualization. Glucosamine AuNPs at 0.02 mg/mL combined with meropenem at 1 mg/mL showed greater biofilm inhibition (72%) on the endotracheal tube than glucosamine nanoparticles at 0.02 mg/mL alone (26%) (p = 0.001). The scanning electron microscopic visualization revealed that the untreated P. aeruginosa biofilm was denser than the glucosamine nanoparticles-treated biofilm, whether combined with meropenem or using glucosamine nanoparticles alone. The combination of glucosamine AuNPs and meropenem may have the synergistic effect of inhibiting biofilm production of P. aeruginosa on the endotracheal tubes of patients with mechanical ventilation. Conducting additional experiments to explore the impact of combining glucosamine-coated gold nanoparticles (AuNPs) with meropenem on the inhibition of biofilm production by clinical P. aeruginosa isolates would be beneficial.}, } @article {pmid38611989, year = {2024}, author = {Tzimas, K and Rahiotis, C and Pappa, E}, title = {Biofilm Formation on Hybrid, Resin-Based CAD/CAM Materials for Indirect Restorations: A Comprehensive Review.}, journal = {Materials (Basel, Switzerland)}, volume = {17}, number = {7}, pages = {}, doi = {10.3390/ma17071474}, pmid = {38611989}, issn = {1996-1944}, abstract = {Hybrid materials are a recent addition in the field of restorative dentistry for computer-aided design/computer-aided manufacturing (CAD/CAM) indirect restorations. The long-term clinical success of modern dental restorative materials is influenced by multiple factors. Among the characteristics affecting the longevity of a restoration, the mechanical properties and physicοchemical interactions are of utmost importance. While numerous researchers constantly evaluate mechanical properties, the biological background of resin-based CAD/CAM biomaterials is scarcely investigated and, therefore, less described in the literature. This review aims to analyze biofilm formation on the surfaces of novel, hybrid, resin-based CAD/CAM materials and evaluate the methodological protocols followed to assess microbial growth. It is demonstrated that the surface structure, the composition and the finishing and polishing procedures on the surface of a dental restorative material influence initial bacterial adhesion; however, most studies focus on in vitro protocols, and in vivo and/or in situ research of microbiomics in CAD/CAM restorative materials is lacking, obstructing an accurate understanding of the bioadhesion phenomenon in the oral cavity.}, } @article {pmid38611426, year = {2024}, author = {Aydin, A and Suleymanoglu, AA and Abdramanov, A and Paulsen, P and Dumen, E}, title = {Detection of Extended Spectrum ß-Lactamase-Producing Escherichia coli with Biofilm Formation from Chicken Meat in Istanbul.}, journal = {Foods (Basel, Switzerland)}, volume = {13}, number = {7}, pages = {}, doi = {10.3390/foods13071122}, pmid = {38611426}, issn = {2304-8158}, abstract = {Antimicrobial resistance is one of the major public health problems worldwide. This study aimed to detect the presence of extended-spectrum β-lactamase-(ESBL-)producing Escherichia (E.) coli in chicken meat in Istanbul, Türkiye. Raw chicken meat samples (n = 208) were collected from different sale points and analyzed for ESBL-producing E. coli. In total, 101 (48.5%) isolates were confirmed as E. coli by PCR, of which 80/101 (79.2%) demonstrated multiple antibiotic resistance. Resistance against amoxicillin-clavulanic acid was most frequent (87.1%). Eighteen isolates (17.8%) demonstrated phenotypical ESBL resistance, as assessed by the double disc synergy test (DDST). Isolates were tested for the presence of β-lactamase genes and mobilized colistin-resistant genes. The blaTEM group was most frequently detected (97.02%), followed by blaCTX m (45.5%), blaSHV (9.9%), and blaOXA-2 (0.9%). However, mcr genes and blaNDM,blaKPC, blaVIM, and blaOXA-48 genes were not found in any isolate. E. coli strains were tested for biofilm formation in six different media [Nutrient broth, LB broth, Tryptone Soya broth (TSB), TSB containing 1% sucrose, TSB containing 0.6% yeast extract, and BHI]. Biofilm formation by E. coli isolates (44/101, 43.5%) was highest in TSB with 1% sucrose. It is worth noting that all biofilm-producing isolates were found to harbor the blaTEM-1 gene, which can indicate a high level of antibiotic resistance. This is the first report about ESBL-producing E. coli in poultry meat, the exposure of consumers in Istanbul metropolitan areas, and the ability of E. coli from this region to produce biofilms.}, } @article {pmid38611380, year = {2024}, author = {Yang, Y and Kong, X and Niu, B and Yang, J and Chen, Q}, title = {Differences in Biofilm Formation of Listeria monocytogenes and Their Effects on Virulence and Drug Resistance of Different Strains.}, journal = {Foods (Basel, Switzerland)}, volume = {13}, number = {7}, pages = {}, doi = {10.3390/foods13071076}, pmid = {38611380}, issn = {2304-8158}, abstract = {Listeria monocytogenes is recognized as one of the primary pathogens responsible for foodborne illnesses. The ability of L. monocytogenes to form biofilms notably increases its resistance to antibiotics such as ampicillin and tetracycline, making it exceedingly difficult to eradicate. Residual bacteria within the processing environment can contaminate food products, thereby posing a significant risk to public health. In this study, we used crystal violet staining to assess the biofilm-forming capacity of seven L. monocytogenes strains and identified ATCC 19112 as the strain with the most potent biofilm-forming. Subsequent fluorescence microscopy observations revealed that the biofilm-forming capacity was markedly enhanced after two days of culture. Then, we investigated into the factors contributing to biofilm formation and demonstrated that strains with more robust extracellular polymer secretion and self-agglutination capabilities exhibited a more pronounced ability to form biofilms. No significant correlation was found between surface hydrophobicity and biofilm formation capability. In addition, we found that after biofilm formation, the adhesion and invasion of cells were enhanced and drug resistance increased. Therefore, we hypothesized that the formation of biofilm makes L. monocytogenes more virulent and more difficult to remove by antibiotics. Lastly, utilizing RT-PCR, we detected the expression levels of genes associated with biofilm formation, including those involved in quorum sensing (QS), flagellar synthesis, and extracellular polymer production. These genes were significantly upregulated after biofilm formation. These findings underscore the critical relationship between extracellular polymers, self-agglutination abilities, and biofilm formation. In conclusion, the establishment of biofilms not only enhances L. monocytogenes' capacity for cell invasion and adhesion but also significantly increases its resistance to drugs, presenting a substantial threat to food safety.}, } @article {pmid38611358, year = {2024}, author = {Kulišová, M and Rabochová, M and Lorinčík, J and Brányik, T and Hrudka, J and Scholtz, V and Jarošová Kolouchová, I}, title = {Exploring Non-Thermal Plasma and UV Radiation as Biofilm Control Strategies against Foodborne Filamentous Fungal Contaminants.}, journal = {Foods (Basel, Switzerland)}, volume = {13}, number = {7}, pages = {}, doi = {10.3390/foods13071054}, pmid = {38611358}, issn = {2304-8158}, support = {22-13745S//Czech Science Foundation/ ; LM2023041//Ministry of Education Youth and Sports/ ; }, abstract = {In recent years, non-thermal plasma (NTP) has emerged as a promising tool for decontamination and disinfection within the food industry. Given the increasing resistance of microbial biofilms to conventional disinfectants and their adverse environmental effects, this method has significant potential for eliminating biofilm formation or mitigating the metabolic activity of grown biofilms. A comparative study was conducted evaluating the efficacy of UV radiation and NTP in eradicating mature biofilms of four common foodborne filamentous fungal contaminants: Alternaria alternata, Aspergillus niger, Fusarium culmorum, and Fusarium graminearum. The findings reveal that while UV radiation exhibits variable efficacy depending on the duration of exposure and fungal species, NTP induces substantial morphological alterations in biofilms, disrupting hyphae, and reducing extracellular polymeric substance production, particularly in A. alternata and F. culmorum. Notably, scanning electron microscopy analysis demonstrates significant disruption of the hyphae in NTP-treated biofilms, indicating its ability to penetrate the biofilm matrix, which is a promising outcome for biofilm eradication strategies. The use of NTP could offer a more environmentally friendly and potentially more effective alternative to traditional disinfection methods.}, } @article {pmid38610253, year = {2024}, author = {Longo, M and Lelchat, F and Le Baut, V and Rioual, S and Faÿ, F and Lescop, B and Hellio, C}, title = {Tracking of Bacteriophage Predation on Pseudomonas aeruginosa Using a New Radiofrequency Biofilm Sensor.}, journal = {Sensors (Basel, Switzerland)}, volume = {24}, number = {7}, pages = {}, doi = {10.3390/s24072042}, pmid = {38610253}, issn = {1424-8220}, abstract = {Confronting the challenge of biofilm resistance and widespread antimicrobial resistance (AMR), this study emphasizes the need for innovative monitoring methods and explores the potential of bacteriophages against bacterial biofilms. Traditional methods, like optical density (OD) measurements and confocal microscopy, crucial in studying biofilm-virus interactions, often lack real-time monitoring and early detection capabilities, especially for biofilm formation and low bacterial concentrations. Addressing these gaps, we developed a new real-time, label-free radiofrequency sensor for monitoring bacteria and biofilm growth. The sensor, an open-ended coaxial probe, offers enhanced monitoring of bacterial development stages. Tested on a biological model of bacteria and bacteriophages, our results indicate the limitations of traditional OD measurements, influenced by factors like sedimented cell fragments and biofilm formation on well walls. While confocal microscopy provides detailed 3D biofilm architecture, its real-time monitoring application is limited. Our novel approach using radio frequency measurements (300 MHz) overcomes these shortcomings. It facilitates a finer analysis of the dynamic interaction between bacterial populations and phages, detecting real-time subtle changes. This method reveals distinct phases and breakpoints in biofilm formation and virion interaction not captured by conventional techniques. This study underscores the sensor's potential in detecting irregular viral activity and assessing the efficacy of anti-biofilm treatments, contributing significantly to the understanding of biofilm dynamics. This research is vital in developing effective monitoring tools, guiding therapeutic strategies, and combating AMR.}, } @article {pmid38609629, year = {2024}, author = {}, title = {Introducing guided biofilm therapy.}, journal = {British dental journal}, volume = {236}, number = {7}, pages = {565}, doi = {10.1038/s41415-024-7324-9}, pmid = {38609629}, issn = {1476-5373}, } @article {pmid38609420, year = {2024}, author = {Dzofou Ngoumelah, D and Heggeset, TMB and Haugen, T and Sulheim, S and Wentzel, A and Harnisch, F and Kretzschmar, J}, title = {Author Correction: Effect of model methanogens on the electrochemical activity, stability, and microbial community structure of Geobacter spp. dominated biofilm anodes.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {41}, doi = {10.1038/s41522-024-00513-9}, pmid = {38609420}, issn = {2055-5008}, } @article {pmid38609218, year = {2024}, author = {Gao, B and Cai, H and Xu, B and Yang, F and Dou, X and Dong, Q and Yan, H and Bu, X and Li, Z}, title = {Growth, biofilm formation, and motility of Listeria monocytogenes strains isolated from food and clinical samples located in Shanghai (China).}, journal = {Food research international (Ottawa, Ont.)}, volume = {184}, number = {}, pages = {114232}, doi = {10.1016/j.foodres.2024.114232}, pmid = {38609218}, issn = {1873-7145}, abstract = {Listeria monocytogenes is a common foodborne pathogen that frequently causes global outbreaks. In this study, the growth characteristics, biofilm formation ability, motility ability and whole genome of 26 L. monocytogenes strains isolated from food and clinical samples in Shanghai (China) from 2020 to 2022 were analyzed. There are significant differences among isolates in terms of growth, biofilm formation, motility, and gene expression. Compared with other sequence type (ST) types, ST1930 type exhibited a significantly higher maximum growth rate, the ST8 type demonstrated a stronger biofilm formation ability, and the ST121 type displayed greater motility ability. Furthermore, ST121 exhibited significantly high mRNA expression levels compared with other ST types in virulence genes mpl, fbpA and fbpB, the quorum sensing gene luxS, starvation response regulation gene relA, and biofilm adhesion related gene bapL. Whole-genome sequencing (WGS) analyses indicated the isolates of lineage I were mostly derived from clinical, and the isolates of lineage II were mostly derived from food. The motility ability, along with the expression of genes associated with motility (motA and motB), exhibited a significantly higher level in lineage II compared with lineage I. The isolates from food exhibited significantly higher motility ability compared with isolates from clinical. By integrating growth, biofilm formation, motility phenotype with molecular and genotyping information, it is possible to enhance comprehension of the association between genes associated with these characteristics in L. monocytogenes.}, } @article {pmid38608889, year = {2024}, author = {Chu, WC and Gao, YY and Wu, YX and Liu, FF}, title = {Biofilm of petroleum-based and bio-based microplastics in seawater in response to Zn(II): Biofilm formation, community structure, and microbial function.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {172397}, doi = {10.1016/j.scitotenv.2024.172397}, pmid = {38608889}, issn = {1879-1026}, abstract = {Microplastic biofilms are novel vectors for the transport and spread of pathogenic and drug-resistant bacteria. With the increasing use of bio-based plastics, there is an urgent need to investigate the microbial colonization characteristics of these materials in seawater, particularly in comparison with conventional petroleum-based plastics. Furthermore, the effect of co-occurring contaminants, such as heavy metals, on the formation of microplastic biofilms and bacterial communities remains unclear. In this study, we compared the biofilm bacterial community structure of petroleum-based polyethylene (PE) and bio-based polylactic acid (PLA) in seawater under the influence of zinc ions (Zn[2+]). Our findings indicate that the biofilm on PLA microplastics in the late stage was impeded by the formation of a mildly acidic microenvironment resulting from the hydrolysis of the ester group on PLA. The PE surface had higher bacterial abundance and diversity, with a more intricate symbiotic pattern. The bacterial structures on the two types of microplastics were different; PE was more conducive to the colonization of anaerobic bacteria, whereas PLA was more favorable for the colonization of aerobic and acid-tolerant species. Furthermore, Zn increased the proportion of the dominant genera that could utilize microplastics as a carbon source, such as Alcanivorax and Nitratireductor. PLA had a greater propensity to harbor and disseminate pathogenic and drug-resistant bacteria, and Zn promoted the enrichment and spread of harmful bacteria such as, Pseudomonas and Clostridioides. Therefore, further research is essential to fully understand the potential environmental effects of bio-based microplastics and the role of heavy metals in the dynamics of bacterial colonization.}, } @article {pmid38608880, year = {2024}, author = {Zhao, Y and Zhang, J and Ni, M and Pan, Y and Li, L and Ding, Y}, title = {Cultivation of phosphate-accumulating biofilm: Study of the effects of acyl-homoserine lactones (AHLs) and cyclic dimeric guanosine monophosphate (c-di-GMP) on the formation of biofilm and the enhancement of phosphate metabolism capacity.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {172408}, doi = {10.1016/j.scitotenv.2024.172408}, pmid = {38608880}, issn = {1879-1026}, abstract = {This study investigated the mechanisms of microbial growth and metabolism during biofilm cultivation in the biofilm sequencing batch reactor (BSBR) process for phosphate (P) enrichment. The results showed that the sludge discharge was key to biofilm growth, as it terminated the competition for carbon (C) source between the nascent biofilm and the activated sludge. For the tested reactor, after the sludge discharge on 18 d, P metabolism and C source utilization improved significantly, and the biofilm grew rapidly. The P concentration of the recovery liquid reached up to 157.08 mg/L, which was sufficient for further P recovery via mineralization. Meta-omics methods were used to analyze metabolic pathways and functional genes in microbial growth during biofilm cultivation. It appeared that the sludge discharge activated the key genes of P metabolism and inhibited the key genes of C metabolism, which strengthened the polyphosphate-accumulating metabolism (PAM) as a result. The sludge discharge not only changed the types of polyphosphate-accumulating organisms (PAOs) but also promoted the growth of dominant PAOs. Before the sludge discharge, the necessary metabolic abilities that were spread among different microorganisms gradually concentrated into a small number of PAOs, and after the sludge discharge, they further concentrated into Candidatus_Contendobacter (P3) and Candidatus_Accumulibacter (P17). The messenger molecule C-di-GMP, produced mostly by P3 and P17, facilitated P enrichment by regulating cellular P and C metabolism. The glycogen-accumulating organism (GAO) Candidatus_Competibacter secreted N-Acyl homoserine lactones (AHLs), which stimulated the secretion of protein in extracellular polymeric substances (EPS), thus promoting the adhesion of microorganisms to biofilm and improving P metabolism via EPS-based P adsorption. Under the combined action of the dominant GAOs and PAOs, AHLs and C-di-GMP mediated QS to promote biofilm development and P enrichment. The research provides theoretical support for the cultivation of biofilm and its wider application.}, } @article {pmid38605850, year = {2024}, author = {Cheng, Y and Huangfu, Y and Zhao, T and Wang, L and Yang, J and Liu, J and Feng, Z and Que, K}, title = {Thermosensitive hydrogel with programmed dual-octenidine release combating biofilm for the treatment of apical periodontitis.}, journal = {Regenerative biomaterials}, volume = {11}, number = {}, pages = {rbae031}, pmid = {38605850}, issn = {2056-3418}, abstract = {The utilization of intracanal medicaments is an indispensable procedure in root-canal treatment. However, the conventional intracanal medicaments still need improvement regarding antimicrobial efficacy and ease of clinical operation. To address the above issues, OCT/PECT@OCT + ALK composite hydrogel characterized by programming sequential release of dual antimicrobial agents has been proposed. Thanks to the self-assemble ability of amphiphilic copolymer poly(ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT), dual hydrophilic and hydrophobic antimicrobial agents could be easily encapsulated in the hydrogel system and tailored for sequential drug release for a better antibiofilm effect. The hydrophilic octenidine (Octenidine dihydrochloride, OCT-HCl) is encapsulated in the hydrophilic part of hydrogel for instantaneous elevating the drug concentration through bursting release, and the hydrophobic octenidine (Octenidine, OCT) is further loaded into the PECT nanoparticles to achieve a slower and sustained-release profile. Additionally, calcium hydroxide (Ca(OH)2) was incorporated into the system and evenly dispersed among PECT nanoparticles to create an alkaline (ALK) environment, synergistically enhancing the antibiofilm effect with higher efficiency and prolonged duration. The antibiofilm effect has been demonstrated in root-canal models and apical periodontitis rats, exhibiting superior performance compared to clinically used Ca(OH)2 paste. This study demonstrates that OCT/PECT@OCT + ALK composite thermosensitive hydrogel is a potential intracanal medicament with excellent antibiofilm effect and clinical operability.}, } @article {pmid38605736, year = {2024}, author = {Sagar, PK and Sharma, P and Singh, R}, title = {Anti-Quorum Sensing and Anti-Biofilm Activity of Ginger (Zingiber officinale) Rhizomes against Multidrug-Resistant Clinical Isolates of Pseudomonas aeruginosa.}, journal = {Avicenna journal of medical biotechnology}, volume = {16}, number = {1}, pages = {49-56}, pmid = {38605736}, issn = {2008-2835}, abstract = {BACKGROUND: The aim of this study was to determination of Anti-Quorum Sensing (AQS) and anti-biofilm potential of the methanol extract of ginger (Zingiber officinale) rhizomes against multidrug-resistant clinical isolates of Pseudomonas aeruginosa (P. aeruginosa).

METHODS: The AQS activity of ginger was determined against Chromobacterium violaceum (C. violaceum) ATCC 12472 (CV12472), a biosensor strain, in qualitative manner using the agar well diffusion method. The violacein pigment inhibition was assessed to confirm AQS activity of ginger. The AQS potential of sub-minimum Inhibitory Concentrations (sub-MICs) of the ginger extract was determined by targeting different QS regulated virulence factors, including swarming motility (using swarm diameter measurement method), pyocyanin pigment (using chloroform extraction method), Exopolysaccharide (EPS) (using phenol-sulphuric acid method), and biofilm formation (using microtiter plate assay), against clinical isolates (CIs 2, 3, and 4) and standard reference strain of P. aeruginosa (PA01).

RESULTS: The AQS activity of methanol extract of ginger was confirmed against C. violaceum (CV12472) as inhibition of violacein pigment formation without effecting the growth of CIs and PA01 of P. aeruginosa. The ginger extract exhibited concentration-dependent inhibition of virulence factors and biofilm formation. The maximum reduction was found in swarming motility, pyocyanin, EPS and biofilm formation against PA01 (51.38%), CI3 (57.91%), PA01 (63.29%) and CI2 (64.37%), respectively at 1/2 MIC of ginger extract.

CONCLUSION: The results of present study revealed the effective AQS and anti-biofilm potential of Zingiber officinale rhizome methanol extract at a reduced dose (sub-MICs). The extract may be explored as an agent of antimicrobial compounds having AQS and anti-biofilm activity for controlling microbial infection and also for reducing the chances of emergence of resistance in P. aeruginosa.}, } @article {pmid38604376, year = {2024}, author = {Lin, YT and Wang, YC and Xue, YM and Tong, Z and Jiang, GY and Hu, XR and Crittenden, JC and Wang, C}, title = {Decoding the influence of low temperature on biofilm development: The hidden roles of c-di-GMP.}, journal = {The Science of the total environment}, volume = {927}, number = {}, pages = {172376}, doi = {10.1016/j.scitotenv.2024.172376}, pmid = {38604376}, issn = {1879-1026}, abstract = {Biofilms are widely used and play important roles in biological processes. Low temperature of wastewater inhibits the development of biofilms derived from wastewater activated sludge. However, the specific mechanism of temperature on biofilm development is still unclear. This study explored the mechanism of temperature on biofilm development and found a feasible method to enhance biofilm development at low temperature. The amount of biofilm development decreased by approximately 66 % and 55 % at 4 °C and 15 °C, respectively, as compared to 28 °C. The cyclic dimeric guanosine monophosphate (c-di-GMP) concentration also decreased at low temperature and was positively correlated with extracellular polymeric substance (EPS) content, formation, and adhesion strength. Microbial community results showed that low temperature inhibited the normal survival of most microorganisms, but promoted the growth of some psychrophile bacteria like Sporosarcina, Caldilineaceae, Gemmataceae, Anaerolineaceae and Acidobacteriota. Further analysis of functional genes demonstrated that the abundance of functional genes related to the synthesis of c-di-GMP (K18968, K18967 and K13590) decreased at low temperature. Subsequently, the addition of exogenous spermidine increased the level of intracellular c-di-GMP and alleviated the inhibition effect of low temperature on biofilm development. Therefore, the possible mechanism of low temperature on biofilm development could be the inhibition of the microorganism activity and reduction of the communication level between cells, which is the closely related to the EPS content, formation, and adhesion strength. The enhancement of c-di-GMP level through the exogenous addition of spermidine provides an alternative strategy to enhance biofilm development at low temperatures. The results of this study enhance the understanding of the influence of temperature on biofilm development and provide possible strategies for enhancing biofilm development at low temperatures.}, } @article {pmid38602224, year = {2024}, author = {Senhaji-Kacha, A and Akir, A and Broncano-Lavado, A and Esteban, J}, title = {Biofilm prevention concentration of clarithromycin against clinically relevant species of nontuberculous mycobacteria.}, journal = {Revista espanola de quimioterapia : publicacion oficial de la Sociedad Espanola de Quimioterapia}, volume = {}, number = {}, pages = {}, doi = {10.37201/req/014.2024}, pmid = {38602224}, issn = {1988-9518}, abstract = {OBJECTIVE: Mycobacterium avium complex (MAC) and Mycobacterium abscessus are a group of nontuberculous mycobacteria (NTM) that have been described as human pathogens. Their ability to develop biofilms in tissues and medical devices is one of the most important pathogenicity factors, with important implications in diagnosis and treatment. Macrolides are usually considered one of the bases of this treatment.

METHODS: Here we have studied the biofilm prevention concentration (BPC) of 16 strains (n=16) with clarithromycin to avoid the biofilm development by these NTM.

RESULTS: In this study, all M. abscessus strains have similar BPC, while MAC strains showed different values. For MAC the concentrations ranged between 1-16 mg/L, while for M. abscessus the concentration was 32 mg/L for all strains except one that was 64 mg/L.

CONCLUSIONS: These results open the possibility of using macrolides for the prevention of biofilm development in patients with a risk of developing NTM disease.}, } @article {pmid38601931, year = {2024}, author = {Naudin, SA and Ferran, AA and Imazaki, PH and Arpaillange, N and Marcuzzo, C and Vienne, M and Demmou, S and Bousquet-Mélou, A and Ramon-Portugal, F and Lacroix, MZ and Hoede, C and Barret, M and Dupouy, V and Bibbal, D}, title = {Development of an in vitro biofilm model for the study of the impact of fluoroquinolones on sewer biofilm microbiota.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1377047}, pmid = {38601931}, issn = {1664-302X}, abstract = {Sewer biofilms are likely to constitute hotspots for selecting and accumulating antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study aimed to optimize culture conditions to obtain in vitro biofilms, mimicking the biofilm collected in sewers, to study the impact of fluoroquinolones (FQs) on sewer biofilm microbiota. Biofilms were grown on coupons in CDC Biofilm Reactors®, continuously fed with nutrients and inoculum (1/100 diluted wastewater). Different culture conditions were tested: (i) initial inoculum: diluted wastewater with or without sewer biofilm, (ii) coupon material: concrete vs. polycarbonate, and (iii) time of culture: 7 versus 14 days. This study found that the biomass was highest when in vitro biofilms were formed on concrete coupons. The biofilm taxonomic diversity was not affected by adding sewer biofilm to the initial inoculum nor by the coupon material. Pseudomonadales, Burkholderiales and Enterobacterales dominated in the sewer biofilm composition, whereas in vitro biofilms were mainly composed of Enterobacterales. The relative abundance of qnrA, B, D and S genes was higher in in vitro biofilms than sewer biofilm. The resistome of sewer biofilm showed the highest Shannon diversity index compared to wastewater and in vitro biofilms. A PCoA analysis showed differentiation of samples according to the nature of the sample, and a Procrustes analysis showed that the ARG changes observed were linked to changes in the microbial community. The following growing conditions were selected for in vitro biofilms: concrete coupons, initial inoculation with sewer biofilm, and a culture duration of 14 days. Then, biofilms were established under high and low concentrations of FQs to validate our in vitro biofilm model. Fluoroquinolone exposure had no significant impact on the abundance of qnr genes, but high concentration exposure increased the proportion of mutations in gyrA (codons S83L and D87N) and parC (codon S80I). In conclusion, this study allowed the determination of the culture conditions to develop an in vitro model of sewer biofilm; and was successfully used to investigate the impact of FQs on sewer microbiota. In the future, this setup could be used to clarify the role of sewer biofilms in disseminating resistance to FQs in the environment.}, } @article {pmid38601817, year = {2024}, author = {Klein, E and Wurst, R and Rehnlund, D and Gescher, J}, title = {Elucidating the development of cooperative anode-biofilm-structures.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100193}, pmid = {38601817}, issn = {2590-2075}, abstract = {Microbial electrochemical systems are a highly versatile platform technology with a particular focus on the interplay of chemical and electrical energy conversion and offer immense potential for a sustainable bioeconomy. The industrial realization of this potential requires a critical focus on biofilm optimization if performance is to be controlled over a long period of time. Moreover, the aspect and influence of cooperativity has to be addressed as many applied anodic bioelectrochemical systems will most likely be operated with a diversity of interacting microbial species. Hence, the aim of this study was to analyze how interspecies dependence and cooperativity of a model community influence the development of anodic biofilms. To investigate biofilm activity in a spatially resolved manner, a microfluidic bioelectrochemical flow cell was developed that can be equipped with user-defined electrode materials and operates under laminar flow conditions. With this infrastructure, the development of single and co-culture biofilms of the two model organisms Shewanella oneidensis and Geobacter sulfurreducens on graphite electrodes was monitored by optical coherence tomography analysis. The interdependence in the co-culture biofilm was achieved by feeding the community with lactate, which is converted by S. oneidensis into acetate, which in turn serves as substrate for G. sulfurreducens. The results show that co-cultivation resulted in the formation of denser biofilms than in single culture. Moreover, we hypothesize that S. oneidensis in return utilizes the conductive biofilm matrix build by G. sulfurreducens for direct interspecies electron transfer (DIET) to the anode. FISH analysis revealed that the biofilms consisted of approximately two-thirds G. sulfurreducens cells, which most likely formed a conductive 3D network throughout the biofilm matrix, in which evenly distributed tubular S. oneidensis colonies were embedded without direct contact to the anode surface. Live/dead staining shows that the outermost biofilm contained almost exclusively dead cells (98 %), layers near the anode contained 45-56 % and the entire biofilm contained 82 % live cells. Our results exemplify how the architecture of the exoelectrogenic biofilm dynamically adapts to the respective process conditions.}, } @article {pmid38596384, year = {2024}, author = {Ren, J and Wang, M and Zhou, W and Liu, Z}, title = {Efflux pumps as potential targets for biofilm inhibition.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1315238}, pmid = {38596384}, issn = {1664-302X}, abstract = {Biofilms account for a great deal of infectious diseases and contribute significantly to antimicrobial resistance. Efflux pumps confer antimicrobial resistance to microorganisms and involve multiple processes of biofilm formation. Efflux pump inhibitors (EPIs) are attracting considerable attention as a biofilm inhibition strategy. The regulatory functions of efflux pumps in biofilm formation such as mediating adherence, quorum sensing (QS) systems, and the expression of biofilm-associated genes have been increasingly identified. The versatile properties confer efflux pumps both positive and negative effects on biofilm formation. Furthermore, the expression and function of efflux pumps in biofilm formation are species-specific. Therefore, this review aims to detail the double-edged sword role of efflux pumps in biofilm formation to provide potential inhibition targets and give an overview of the effects of EPIs on biofilm formation.}, } @article {pmid38596377, year = {2024}, author = {Chamlagain, M and Hu, J and Sionov, RV and Steinberg, D}, title = {Anti-bacterial and anti-biofilm activities of arachidonic acid against the cariogenic bacterium Streptococcus mutans.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1333274}, pmid = {38596377}, issn = {1664-302X}, abstract = {Streptococcus mutans is a Gram-positive, facultative anaerobic bacterium, which causes dental caries after forming biofilms on the tooth surface while producing organic acids that demineralize enamel and dentin. We observed that the polyunsaturated arachidonic acid (AA) (ω-6; 20:4) had an anti-bacterial activity against S. mutans, which prompted us to investigate its mechanism of action. The minimum inhibitory concentration (MIC) of AA on S. mutans was 25 μg/ml in the presence of 5% CO2, while it was reduced to 6.25-12.5 μg/ml in the absence of CO2 supplementation. The anti-bacterial action was due to a combination of bactericidal and bacteriostatic effects. The minimum biofilm inhibitory concentration (MBIC) was the same as the MIC, suggesting that part of the anti-biofilm effect was due to the anti-bacterial activity. Gene expression studies showed decreased expression of biofilm-related genes, suggesting that AA also has a specific anti-biofilm effect. Flow cytometric analyses using potentiometric DiOC2(3) dye, fluorescent efflux pump substrates, and live/dead SYTO 9/propidium iodide staining showed that AA leads to immediate membrane hyperpolarization, altered membrane transport and efflux pump activities, and increased membrane permeability with subsequent membrane perforation. High-resolution scanning electron microscopy (HR-SEM) showed remnants of burst bacteria. Furthermore, flow cytometric analysis using the redox probe 2',7'-dichlorofluorescein diacetate (DCFHDA) showed that AA acts as an antioxidant in a dose-dependent manner. α-Tocopherol, an antioxidant that terminates the radical chain, counteracted the anti-bacterial activity of AA, suggesting that oxidation of AA in bacteria leads to the production of cytotoxic radicals that contribute to bacterial growth arrest and death. Importantly, AA was not toxic to normal Vero epithelial cells even at 100 μg/ml, and it did not cause hemolysis of erythrocytes. In conclusion, our study shows that AA is a potentially safe drug that can be used to reduce the bacterial burden of cariogenic S. mutans.}, } @article {pmid38596374, year = {2024}, author = {Zhao, Y and Guo, S and Li, S and Ye, E and Wang, W and Wang, T and Wen, Y and Guo, L}, title = {Ultrasonic-assisted extraction, anti-biofilm activity, and mechanism of action of Ku Shen (Sophorae Flavescentis Radix) extracts against Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1379341}, pmid = {38596374}, issn = {1664-302X}, abstract = {The objective of this study is to optimize the ultrasonic-assisted extraction process of Ku Shen (Sophorae Flavescentis Radix) extracts (KSE) against Vibrio parahaemolyticus and explore their anti-biofilm activity and mechanism of action. The ultrasonic-assisted extraction process of KSE optimized by single factor experiment, Box-Behnken design and response surface methodology was as follows: 93% ethanol as solvent, liquid/material ratio of 30 mL/g, ultrasonic power of 500 W, extraction temperature of 80°C and time of 30 min. Under these conditions, the diameter of inhibition circle of KSE was 15.60 ± 0.17 mm, which had no significant difference with the predicted value. The yield of dried KSE is 32.32 ± 0.57% and the content of total flavonoids in KSE was 57.02 ± 5.54%. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of KSE against V. parahaemolyticus were 0.25 and 0.5 mg/mL, respectively. Crystal violet staining, Congo red plate, spectrophotometry, CCK-8 and scanning electron microscopy were used to investigate the activity and mechanism of action of KSE against V. parahaemolyticus biofilm. The results showed that the sub-MIC of KSE could significantly inhibit biofilm formation, reduce the synthesis of polysaccharide intercellular adhesin (PIA) and the secretion of extracellular DNA. In addition, the inhibition rate of biofilm formation and clearance rate of mature biofilm of 1.0 mg/mL KSE were 85.32 and 74.04%, and the reduction rate of metabolic activity of developing and mature biofilm were 77.98 and 74.46%, respectively. These results were confirmed by visual images obtained by scanning electron microscopy. Therefore, KSE has the potential to further isolate the anti-biofilm agent and evaluate it for the preservation process of aquatic products.}, } @article {pmid38596007, year = {2024}, author = {Gricajeva, A and Buchovec, I and Kalėdienė, L and Badokas, K and Vitta, P}, title = {Evaluation of visible light and natural photosensitizers against Staphylococcus epidermidis and Staphylococcus saprophyticus planktonic cells and biofilm.}, journal = {Heliyon}, volume = {10}, number = {7}, pages = {e28811}, pmid = {38596007}, issn = {2405-8440}, abstract = {Antimicrobial photoinactivation (API) has shown some promise in potentially treating different nosocomial bacterial infections, however, its application on staphylococci, especially other than Staphylococcus aureus or methicillin-resistant S. aureus (MRSA) species is still limited. Although S. aureus is a well-known and important nosocomial pathogen, several other species of the genus, particularly coagulase-negative Staphylococcus (CNS) species such as Staphylococcus epidermidis and Staphylococcus saprophyticus, can also cause healthcare-associated infections and foodborne intoxications. CNS are often involved in resilient biofilm formation on medical devices and can cause infections in patients with compromised immune systems or those undergoing invasive procedures. In this study, the effects of chlorophyllin and riboflavin-mediated API on S. epidermidis and S. saprophyticus planktonic cells and biofilm are demonstrated for the first time. Based on the residual growth determination and metabolic reduction ability changes, higher inactivating efficiency of chlorophyllin-mediated API was determined against the planktonic cells of both tested species of bacteria and against S. saprophyticus biofilm. Some insights on whether aqueous solutions of riboflavin and chlorophyllin, when illuminated with optimal exciting wavelength (440 nm and 402 nm, respectively) generate O2[-•], are also provided in this work.}, } @article {pmid38595719, year = {2024}, author = {ElNaggar, MH and Abdelmohsen, UR and Abdel Bar, FM and Kamer, AA and Bringmann, G and Elekhnawy, E}, title = {Investigation of bioactive components responsible for the antibacterial and anti-biofilm activities of Caroxylon volkensii by LC-QTOF-MS/MS analysis and molecular docking.}, journal = {RSC advances}, volume = {14}, number = {16}, pages = {11388-11399}, pmid = {38595719}, issn = {2046-2069}, abstract = {Caroxylon volkensii is a wild desert plant of the family Amaranthaceae. This study represents the first report of the metabolomic profiling of C. volkensii by liquid chromatography quadrupole-time-of-flight tandem mass spectrometry (LC-QTOF-MS/MS). The dereplication study of its secondary metabolites led to the characterization of 66 known compounds. These compounds include catecholamines, tyramine derivatives, phenolic acids, triterpenoids, flavonoids, and others. A new tyramine derivative, alongside other known compounds, was reported for the first time in the Amaranthaceae family. The new derivative and the first-reported compounds were putatively identified through MS/MS fragmentation data. Given the notorious taxonomical challenges within the genus Salsola, to which C. volkensii previously belonged, our study could offer a valuable insight into its chemical fingerprint and phylogenetic relationship to different Salsola species. The antibacterial potential of C. volkensii methanolic extract (CVM) against Pseudomonas aeruginosa was screened. The minimum inhibitory concentration (MIC) of CVM ranged from 32 to 256 μg mL[-1]. The anti-quorum sensing potential of CVM resulted in a decrease in the percentage of strong and moderate biofilm-forming isolates from 47.83% to 17.39%. It revealed a concentration-dependent inhibitory activity on violacein formation by Chromobacterium violaceum. Moreover, CVM exhibited an in vivo protective potential against the killing capacity of P. aeruginosa isolates. A molecular docking study revealed that the quorum-sensing inhibitory effect of CVM can be attributed to the binding of tyramine conjugates, ethyl-p-digallate, and isorhamnetin to the transcriptional global activator LasR.}, } @article {pmid38595637, year = {2024}, author = {Alam, MK and Alruwaili, SRF and Alderaan, RAI and Alanazi, DSA}, title = {Nanoparticles in Preventing Biofilm Formation on Orthodontic Brackets: Clinical Study.}, journal = {Journal of pharmacy & bioallied sciences}, volume = {16}, number = {Suppl 1}, pages = {S534-S536}, pmid = {38595637}, issn = {0976-4879}, abstract = {UNLABELLED: This study investigates the effectiveness of nanoparticles in preventing the formation of biofilms on orthodontic brackets. Biofilm formation is a common concern during orthodontic treatment, as it can lead to oral health issues.

MATERIALS AND METHODS: The study utilized a randomized controlled trial design. The participants were divided into two groups: the experimental group and the control group. The experimental group received orthodontic brackets coated with nanoparticles, while the control group received regular brackets. The patients' oral hygiene was monitored, and plaque index scores were recorded at specific intervals.

RESULTS: The results of this study demonstrated a significant difference in biofilm formation between the two groups. The experimental group, which had orthodontic brackets with nanoparticle coatings, exhibited a lower plaque index compared to the control group. The mean plaque index score difference was statistically significant (P < 0.05), indicating that the nanoparticles effectively reduced biofilm formation on orthodontic brackets.

CONCLUSION: In conclusion, the findings of this clinical study suggest that the utilization of nanoparticles as coatings for orthodontic brackets can be an effective approach to prevent biofilm formation.}, } @article {pmid38593965, year = {2024}, author = {Bounaga, A and Alsanea, A and Danouche, M and Rittmann, BE and Zhou, C and Boulif, R and Zeroual, Y and Benhida, R and Lyamlouli, K}, title = {Elemental sulfur biorecovery from phosphogypsum using oxygen-membrane biofilm reactor: Bioreactor parameters optimization, metagenomic analysis and metabolic prediction of the biofilm activity.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130680}, doi = {10.1016/j.biortech.2024.130680}, pmid = {38593965}, issn = {1873-2976}, abstract = {This work investigated elemental sulfur (S[0]) biorecovery from Phosphogypsum (PG) using sulfur-oxidizing bacteria in an O2-based membrane biofilm reactor (MBfR). The system was first optimized using synthetic sulfide medium (SSM) as influent, then switched to biogenic sulfide medium (BSM) generated by biological reduction of PG alkaline leachate. The results using SSM had high sulfide-oxidation efficiency (98 %), sulfide to S[0] conversion (∼90 %), and S0 production rate up to 2.7 g S[0]/(m[2].d), when the O2/S ratio was ∼0.5 g O2/g S. With the BSM influent, the system maintained high sulfide-to-S[0] conversion rate (97 %), and S[0]-production rate of 1.6 g S[0]/(m[2].d). Metagenomic analysis revealed that Thauera was the dominant genus in SSM and BSM biofilms. Furthermore, influent composition affected the bacterial community structure and abundances of functional microbial sulfur genes, modifying the sulfur-transformation pathways in the biofilms. Overall, this work shows promise for O2-MBfR usage in S[0] biorecovery from PG leachate and sulfidogenic effluents.}, } @article {pmid38592866, year = {2024}, author = {Matotoka, MM and Masoko, P}, title = {Evaluation of the Antioxidant, Cytotoxicity, Antibacterial, Anti-Motility, and Anti-Biofilm Effects of Myrothamnus flabellifolius Welw. Leaves and Stem Defatted Subfractions.}, journal = {Plants (Basel, Switzerland)}, volume = {13}, number = {6}, pages = {}, pmid = {38592866}, issn = {2223-7747}, support = {N624//University of Limpopo/ ; }, abstract = {The formation of biofilms underscores the challenge of treating bacterial infections. The study aimed to assess the antioxidant, cytotoxicity, antibacterial, anti-motility, and anti-biofilm effects of defatted fractions from Myrothamnus flabellifolius (resurrection plant). Antioxidant activity was assessed using DPPH radical scavenging and hydrogen peroxide assays. Cytotoxicity was screened using a brine shrimp lethality assay. Antibacterial activity was determined using the micro-dilution and growth curve assays. Antibiofilm potential was screened using the crystal violet and tetrazolium reduction assay. Liquid-liquid extraction of crude extracts concentrated polyphenols in the ethyl acetate and n-butanol fractions. Subsequently, these fractions had notable antioxidant activity and demonstrated broad-spectrum antibacterial activity against selected Gram-negative and Gram-positive bacteria and Mycobacterium smegmatis (MIC values < 630 μg/mL). Growth curves showed that the bacteriostatic inhibition by the ethyl acetate fractions was through the extension of the lag phase and/or suppression of the growth rate. The sub-inhibitory concentrations of the ethyl acetate fractions inhibited the swarming motility of Pseudomonas aeruginosa and Klebsiella pneumoniae by 100% and eradicated more than 50% of P. aeruginosa biofilm biomass. The polyphenolic content of M. flabellifolius plays an important role in its antibacterial, anti-motility, and antibiofilm activity, thus offering an additional strategy to treat biofilm-associated infections.}, } @article {pmid38590167, year = {2024}, author = {Li, J and Yu, J and Song, Y and Wang, S and Mu, G and Tuo, Y}, title = {Exopolysaccharides and Surface-Layer Proteins Expressed by Biofilm-State Lactiplantibacillus plantarum Y42 Play Crucial Role in Preventing Intestinal Barrier and Immunity Dysfunction of Balb/C Mice Infected by Listeria monocytogenes ATCC 19115.}, journal = {Journal of agricultural and food chemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.jafc.4c00460}, pmid = {38590167}, issn = {1520-5118}, abstract = {Our previous study showed that Lactiplantibacillus plantarum Y42 in the biofilm state can produce more exopolysaccharides and surface-layer proteins and showed a stronger promoting effect on intestinal barrier function than that in the planktonic state. In this study, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites (exopolysaccharides and surface-layer proteins) increased the expression of Occludin, Claudin-1, ZO-1, and MUC2 in the gut of the Balb/C mice after exposure to Listeria monocytogenes ATCC 19115 and inhibited the activation of the NLRP3 inflammasome pathway, which in turn reduced the levels of inflammatory cytokines IL-1β and IL-18 in the serum of the mice. Furthermore, oral administration of the live/pasteurized planktonic or biofilm L. plantarum Y42 and its metabolites increased the abundance of beneficial bacteria (e.g., Lachnospiraceae_NK4A136_group and Prevotellaceae_UCG-001) while reducing the abundance of harmful bacteria (e.g., norank_f__Muribaculaceae) in the gut of the mice, in line with the increase of short-chain fatty acids and indole derivatives in the feces of the mice. Notably, biofilm L. plantarum Y42 exerted a better preventing effect on the intestinal barrier dysfunction of the Balb/C mice due to the fact that biofilm L. plantarumY42 expressed more exopolysaccharides and surface-layer proteins than the planktonic state. These results provide data support for the use of exopolysaccharides and surface-layer proteins extracted from biofilm-state L. plantarum Y42 as functional food ingredients in preventing intestinal barrier dysfunction.}, } @article {pmid38588781, year = {2024}, author = {Yang, S and Peng, Y and Hou, F and Pang, H and Jiang, L and Sun, S and Li, J and Zhang, L}, title = {Rapid establishment of municipal sewage partial denitrification-anammox for nitrogen removal through inoculation with side-stream anammox biofilm without domestication.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130679}, doi = {10.1016/j.biortech.2024.130679}, pmid = {38588781}, issn = {1873-2976}, abstract = {Mainstream partial denitrification anammox was achieved through inoculation of side-stream mature partial nitritation anammox biofilm without domestication. The contribution of anammox to nitrogen removal was 29.4 %. Moreover, prolonging anoxic hydraulic retention time and introducing side-stream nitrite under different carbon/nitrogen ratios enriched anammox bacteria. The abundance of anammox bacteria increased by ∼ 10 times ((2.19 ± 0.17) × 10[12] copies gene / g dry sludge) with a total relative abundance of 18.51 %. During 258 days of operation, the contribution of anammox to nitrogen removal gradually increased to 68.8 %. The total nitrogen in the effluent decreased to 8.84 mg/L with a total nitrogen removal efficiency of 76.4 % under a carbon/nitrogen ratio of 3. This paper proposes a novel way to rapidly achieve mainstream partial denitrification anammox via inoculation with side-stream mature partial nitritation anammox biofilm. This method achieves advanced nitrogen removal from municipal wastewater, even under low carbon/nitrogen ratios.}, } @article {pmid38588056, year = {2024}, author = {Iungin, O and Shydlovska, O and Moshynets, O and Vasylenko, V and Sidorenko, M and Mickevičius, S and Potters, G}, title = {Metal-based nanoparticles: an alternative treatment for biofilm infection in hard-to-heal wounds.}, journal = {Journal of wound care}, volume = {33}, number = {Sup4a}, pages = {xcix-cx}, doi = {10.12968/jowc.2024.33.Sup4a.xcix}, pmid = {38588056}, issn = {0969-0700}, abstract = {Metal-based nanoparticles (MNPs) are promoted as effective compounds in the treatment of bacterial infections and as possible alternatives to antibiotics. These MNPs are known to affect a broad spectrum of microorganisms using a multitude of strategies, including the induction of reactive oxygen species and interaction with the inner structures of the bacterial cells. The aim of this review was to summarise the latest studies about the effect of metal-based nanoparticles on pathogenic bacterial biofilm formed in wounds, using the examples of Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Pseudomonas aeruginosa, as well as provide an overview of possible clinical applications.}, } @article {pmid38587815, year = {2024}, author = {Vieira, TF and Leitão, MM and Cerqueira, NMFSA and Sousa, SF and Borges, A and Simões, M}, title = {Montelukast and cefoperazone act as anti-quorum sensing and anti-biofilm agents against Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxae088}, pmid = {38587815}, issn = {1365-2672}, abstract = {AIMS: Drug repurposing is an attractive strategy to control biofilm-related infectious diseases. In this study, two drugs (montelukast and cefoperazone) with well-established therapeutic applications were tested on Pseudomonas aeruginosa quorum sensing (QS) inhibition and biofilm control.

METHODS AND RESULTS: The activity of montelukast and cefoperazone was evaluated for Pqs signal inhibition, pyocyanin synthesis, and prevention and eradication of P. aeruginosa biofilms. Cefoperazone inhibited the Pqs system by hindering the production of the autoinducer molecules 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (the Pseudomonas quinolone signal or PQS), corroborating in silico results. P. aeruginosa pyocyanin production was reduced by 50%. The combination of the antibiotics cefoperazone and ciprofloxacin was synergistic for P. aeruginosa biofilm control. On the other hand, montelukast had no relevant effects on the inhibition of the Pqs system and against P. aeruginosa biofilm.

CONCLUSION: This study provides for the first time strong evidence that cefoperazone interacts with the Pqs system, hindering the formation of the autoinducer molecules HHQ and PQS, reducing P. aeruginosa pathogenicity and virulence. Cefoperazone demonstrated a potential to be used in combination with less effective antibiotics (e.g. ciprofloxacin) to potentiate the biofilm control action.}, } @article {pmid38585970, year = {2024}, author = {de Palma, TH and Powers, C and McPartland, MJ and Welch, JM and Ramsey, M}, title = {Essential genes for Haemophilus parainfluenzae survival and biofilm growth.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2024.03.31.587483}, pmid = {38585970}, abstract = {Haemophilus parainfluenzae (Hp) is a Gram-negative, pleomorphic rod, highly prevalent and abundant as a commensal in the human oral cavity, and an infrequent extraoral opportunistic pathogen. Hp occupies multiple niches in the oral cavity, including the tongue dorsum, keratinized gingiva, and the supragingival plaque biofilm. As a member of the HACEK group, Hp is also known to cause infective endocarditis. Additionally, case reports have identified Hp as the causative agent of meningitis, septic arthritis, chronic osteomyelitis, septicemia, and a variety of other infectious diseases. Little is known about how Hp interacts with its neighbors in the healthy biofilm nor about its mechanisms of pathogenesis as an extraoral opportunistic pathogen. To address these unknowns, we identified the essential genomes of two Hp strains and the conditionally essential genes for their growth in in vitro biofilms aerobically and anaerobically. Using transposon insertion sequencing (TnSeq) with a highly saturated mariner transposon library in two strains, the ATCC33392 type-strain (Hp 392) and a commensal oral isolate EL1 (Hp EL1), we show that the essential genome of Hp 392 and Hp EL1 is composed of 395 and 384 genes, respectively. The core essential genome, consisting of 341 essential genes conserved between both strains, was composed of genes associated with genetic information processing, carbohydrate, protein, and energy metabolism. We also identified conditionally essential genes for aerobic and anaerobic biofilm growth, which were associated with carbohydrate and energy metabolism in both strains of Hp . Additionally, RNAseq analysis determined that most genes upregulated during anaerobic growth are not essential for Hp 392 anaerobic biofilm survival. The completion of this library and analysis under these conditions gives us a foundational insight into the basic biology of H. parainfluenzae in differing oxygen conditions, similar to its in vivo oral habitat. Further, the creation of this library presents a valuable tool for further investigation into conditionally essential genes for an organism that lives in close contact with many microbial species in the human oral habitat.}, } @article {pmid38585655, year = {2024}, author = {Li, X and Tian, F and Zhang, B and Zhang, L and Chen, X and Lin, X and Wang, Y and Lin, X and Liu, Y}, title = {Quantitative proteomics analysis reveals an important role of the transcriptional regulator UidR in the bacterial biofilm formation of Aeromonas hydrophila.}, journal = {Frontiers in cellular and infection microbiology}, volume = {14}, number = {}, pages = {1380747}, pmid = {38585655}, issn = {2235-2988}, abstract = {INTRODUCTION: Bacterial biofilm is a well-known characteristic that plays important roles in diverse physiological functions, whereas the current intrinsic regulatory mechanism of its formation is still largely unknown.

METHODS: In the present study, a label-free based quantitative proteomics technology was conducted to compare the differentially expressed proteins (DEPs) between ΔuidR and the wild-type strain in the biofilm state.

RESULTS: The results showed that the deletion of gene uidR encoding a TetR transcriptional regulator significantly increased the biofilm formation in Aeromonas hydrophila. And there was a total of 220 DEPs, including 120 up-regulated proteins and 100 down-regulated proteins between ΔuidR and the wild-type strain based on the quantitative proteomics. Bioinformatics analysis suggested that uidR may affect bacterial biofilm formation by regulating some related proteins in glyoxylic acid and dicarboxylic acid pathway. The expressions of selected proteins involved in this pathway were further confirmed by q-PCR assay, and the results was in accordance with the quantitative proteomics data. Moreover, the deletion of four genes (AHA_3063, AHA_3062, AHA_4140 and aceB) related to the glyoxylic acid and dicarboxylic acid pathway lead to a significant decrease in the biofilm formation.

DISCUSSION: Thus, the results indicated that uidR involved in the regulatory of bacterial biofilm formation, and it may provide a potential target for the drug development and a new clue for the prevention of pathogenic A. hydrophila in the future.}, } @article {pmid38584359, year = {2024}, author = {Akkoyunlu, A and Dülger, G}, title = {Exploring the antibiofilm effects on Escherichia coli biofilm associated with colon cancer and anticancer activities on HCT116 cell line of bee products.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/08927014.2024.2338106}, pmid = {38584359}, issn = {1029-2454}, abstract = {The association between dysbiotic microbiota biofilm and colon cancer has recently begun to attract attention. In the study, the apitherapeutic effects of bee products (honey, bee venom, royal jelly, pollen, perga and propolis) obtained from the endemic Yığılca ecotype of Apis mellifera anatoliaca were investigated. Antibiofilm activity were performed by microplate assay using crystal violet staining to measure adherent biofilm biomass of Escherichia coli capable of forming biofilms. Bee venom showed the highest inhibition effect (73.98%) at 50% concentration. Honey, perga and royal jelly reduced biofilm formation by >50% at all concentrations. The antiproliferation effect on the HCT116 colon cancer cell line was investigated with the water‑soluble tetrazolium salt‑1 assay. After 48 h of honey application at 50% concentration, cell proliferation decreased by 86.51%. The high cytotoxic effects of royal jelly and bee venom are also remarkable. Additionally, apoptotic pathway analysis was performed by ELISA using caspase 3, 8 and 9 enzyme-linked immunosorbent assay kits. All bee products induced a higher expression of caspase 9 compared with caspase 8. Natural products that upregulate caspase proteins are promising therapeutic targets for proliferative diseases.}, } @article {pmid38582469, year = {2024}, author = {Rahmatpour, A and Alizadeh, AH and Alijani, N}, title = {Biofilm hydrogel derived from physical crosslinking (self-assembly) of xanthan gum and chitosan for removing Cd[2+], Ni[2+], and Cu[2+] from aqueous solution.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {131394}, doi = {10.1016/j.ijbiomac.2024.131394}, pmid = {38582469}, issn = {1879-0003}, abstract = {This study aimed to fabricate a series of biodegradable hydrogel films by gelating/physically crosslinking a blend of xanthan gum (XG) and chitosan (CS) in various combinations using a facile, green, and low cost solution casting technique. The adsorption of Cd[2+], Cu[2+] and Ni[2+] by the XG/CS biofilm in aqueous solution was studied in batch experiments to determine how the pH of the solution, contact time, dosage of adsorbent, initial metal ion concentration and ionic strength affect its adsorption. A highly pH-dependent adsorption process was observed for three metal ions. A maximum amount of Cd[2+], Ni[2+], and Cu[2+] ions was adsorbable with 50 mg of the adsorbent at pH 6.0 for an initial metal concentration of 50 mg.L[-1]. An empirical pseudo-second-order model seems to fit the kinetic experimental data reasonably well. It was found that the Langmuir model correlated better with equilibrium isotherm when compared with the Freundlich model. For Cd[2+], Ni[2+], and Cu[2+] ions at 25 °C, the maximum monolayer adsorption capacity was 152.33, 144.79, and 139.71 mg.g[-1], respectively. Furthermore, the biofilm was capable of regenerating, allowing metal ions to adsorb and desorb for five consecutive cycles. Therefore, the developed biodegradable film offers the potential for remediation of specified metal ions.}, } @article {pmid38582122, year = {2024}, author = {Chen, X and Yang, G and Quan, X and Zhu, S and Qin, B and Shou, D and Zhuang, L}, title = {Significance of a minor pilin PilV in biofilm cohesion of Geobacter sulfurreducens.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {172242}, doi = {10.1016/j.scitotenv.2024.172242}, pmid = {38582122}, issn = {1879-1026}, abstract = {Bacterial adhesion plays a vital role in forming and shaping the structure of electroactive biofilms that are essential for the performance of bioelectrochemical systems (BESs). Type IV pili are known to mediate cell adhesion in many Gram-negative bacteria, but the mechanism of pili-mediated cell adhesion of Geobacter species on anode surface remains unclear. Herein, a minor pilin PilV2 was found to be essential for cell adhesion ability of Geobacter sulfurreducens since the lack of pilV2 gene depressed the cell adhesion capability by 81.2 % in microplate and the anodic biofilm density by 23.1 % at -0.1 V and 37.7 % at -0.3 V in BESs. The less cohesiveness of mutant biofilms increased the charge transfer resistance and biofilm resistance, which correspondingly lowered current generation of the pilV2-deficient strain by up to 63.2 % compared with that of the wild-type strain in BESs. The deletion of pilV2 posed an insignificant effect on the production of extracellular polysaccharides, pili, extracellular cytochromes and electron shuttles that are involved in biofilm formation or extracellular electron transfer (EET) process. This study demonstrated the significance of pilV2 gene in cell adhesion and biofilm formation of G. sulfurreducens, as well as the importance of pili-mediated adhesion for EET of electroactive biofilm.}, } @article {pmid38581872, year = {2024}, author = {Niu, C and Zhao, X and Shi, D and Ying, Y and Wu, M and Lai, CY and Guo, J and Hu, S and Liu, T}, title = {Bioreduction of chromate in a syngas-based membrane biofilm reactor.}, journal = {Journal of hazardous materials}, volume = {470}, number = {}, pages = {134195}, doi = {10.1016/j.jhazmat.2024.134195}, pmid = {38581872}, issn = {1873-3336}, abstract = {This study leveraged synthesis gas (syngas), a renewable resource attainable through the gasification of biowaste, to achieve efficient chromate removal from water. To enhance syngas transfer efficiency, a membrane biofilm reactor (MBfR) was employed. Long-term reactor operation showed a stable and high-level chromate removal efficiency > 95%, yielding harmless Cr(III) precipitates, as visualised by scanning electron microscopy and energy dispersive X-ray analysis. Corresponding to the short hydraulic retention time of 0.25 days, a high chromate removal rate of 80 µmol/L/d was attained. In addition to chromate reduction, in situ production of volatile fatty acids (VFAs) by gas fermentation was observed. Three sets of in situ batch tests and two groups of ex situ batch tests jointly unravelled the mechanisms, showing that biological chromate reduction was primarily driven by VFAs produced from in situ syngas fermentation, whereas hydrogen originally present in the syngas played a minor role. 16 S rRNA gene amplicon sequencing has confirmed the enrichment of syngas-fermenting bacteria (such as Sporomusa), who performed in situ gas fermentation leading to the synthesis of VFAs, and organics-utilising bacteria (such as Aquitalea), who utilised VFAs to drive chromate reduction. These findings, combined with batch assays, elucidate the pathways orchestrating synergistic interactions between fermentative microbial cohorts and chromate-reducing microorganisms. The findings facilitate the development of cost-effective strategies for groundwater and drinking water remediation and present an alternative application scenario for syngas.}, } @article {pmid38578301, year = {2024}, author = {Labadie, M and Marchal, F and Merbahi, N and Girbal-Neuhauser, E and Fontagné-Faucher, C and Marcato-Romain, CE}, title = {Cell density and extracellular matrix composition mitigate bacterial biofilm sensitivity to UV-C LED irradiation.}, journal = {Applied microbiology and biotechnology}, volume = {108}, number = {1}, pages = {286}, pmid = {38578301}, issn = {1432-0614}, support = {12050475//Région Occitanie Pyrénées-Méditerranée/ ; }, abstract = {Ultraviolet-C light-emitting diodes (UV-C LEDs) are an emerging technology for decontamination applications in different sectors. In this study, the inactivation of bacterial biofilms was investigated by applying an UV-C LED emitting at 280 nm and by measuring both the influence of the initial cell density (load) and presence of an extracellular matrix (biofilm). Two bacterial strains exposing diverging matrix structures and biochemical compositions were used: Pseudomonas aeruginosa and Leuconostoc citreum. UV-C LED irradiation was applied at three UV doses (171 to 684 mJ/cm[2]) on both surface-spread cells and on 24-h biofilms and under controlled cell loads, and bacterial survival was determined. All surface-spread bacteria, between 10[5] and 10[9] CFU/cm[2], and biofilms at 10[8] CFU/cm[2] showed that bacterial response to irradiation was dose-dependent. The treatment efficacy decreased significantly for L. citreum surface-spread cells when the initial cell load was high, while no load effect was observed for P. aeruginosa. Inactivation was also reduced when bacteria were grown under a biofilm form, especially for P. aeruginosa: a protective effect could be attributed to abundant extracellular DNA and proteins in the matrix of P. aeruginosa biofilms, as revealed by Confocal Laser Scanning Microscopy observations. This study showed that initial cell load and exopolymeric substances are major factors influencing UV-C LED antibiofilm treatment efficacy. KEY POINTS: • Bacterial cell load (CFU/cm[2]) could impact UV-C LED irradiation efficiency • Characteristics of the biofilm matrix have a paramount importance on inactivation • The dose to be applied can be predicted based on biofilm properties.}, } @article {pmid38578180, year = {2024}, author = {Puca, V and Marinacci, B and Pellegrini, B and Campanile, F and Santagati, M and Grande, R}, title = {Biofilm and bacterial membrane vesicles: recent advances.}, journal = {Expert opinion on therapeutic patents}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/13543776.2024.2338101}, pmid = {38578180}, issn = {1744-7674}, abstract = {INTRODUCTION: Bacterial Membrane Vesicles (MVs) play important roles in cell-to-cell communication and transport of several molecules. Such structures are essential components of Extracellular Polymeric Substances (EPS) biofilm matrix of many bacterial species displaying a structural function and a role in virulence and pathogenesis.

AREAS COVERED: In this review were included original articles from the last ten years by searching the keywords 'biofilm' and 'vesicles' on PUBMED and Scopus databases. The articles available in literature mainly describe a positive correlation between bacterial MVs and biofilms formation. The research on Espacenet and Google Patent databases underlines the available patents related to the application of both biofilm MVs and planktonic MVs in inhibiting biofilm formation.

EXPERT OPINION: This review covers and analyzes recent advances in the study of the relationship between bacterial vesicles and biofilm. The huge number of papers discussing the role of MVs confirms the interest aimed at developing new applications in the medical field. The study of the MVs composition and biogenesis may contribute to the identification of components which could be (i) the target for the development of new drugs inhibiting the biofilm establishment; (ii) candidates for the development of vaccines; (iii) biomarkers for the diagnosis of bacterial infections.}, } @article {pmid38577556, year = {2024}, author = {Li, X and Zhang, X and Zhang, M and Luo, X and Zhang, T and Liu, X and Lu, R and Zhang, Y}, title = {Environmental magnesium ion affects global gene expression, motility, biofilm formation and virulence of Vibrio parahaemolyticus.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100194}, pmid = {38577556}, issn = {2590-2075}, abstract = {Vibrio parahaemolyticus is widely distributed in marine ecosystems. Magnesium ion (Mg[2+]) is the second most abundant metal cation in seawater, and plays important roles in the growth and gene expression of V. parahaemolyticus, but lacks the detailed mechanisms. In this study, the RNA sequencing data demonstrated that a total of 1494 genes was significantly regulated by Mg[2+]. The majority of the genes associated with lateral flagella, exopolysaccharide, type III secretion system 2, type VI secretion system (T6SS) 1, T6SS2, and thermostable direct hemolysin were downregulated. A total of 18 genes that may be involved in c-di-GMP metabolism and more than 80 genes encoding putative regulators were also significantly and differentially expressed in response to Mg[2+], indicating that the adaptation process to Mg[2+] stress may be strictly regulated by complex regulatory networks. In addition, Mg[2+] promoted the proliferative speed, swimming motility and cell adhesion of V. parahaemolyticus, but inhibited the swarming motility, biofilm formation, and c-di-GMP production. However, Mg[2+] had no effect on the production of capsular polysaccharide and cytoxicity against HeLa cells. Therefore, Mg[2+] had a comprehensive impact on the physiology and gene expression of V. parahaemolyticus.}, } @article {pmid38575495, year = {2024}, author = {Condado Huerta, MCC and Antunez-Mojica, M and Martínez Plascencia, H and Barrera Molina, AI}, title = {[Agave fructanos promote in vitro biofilm formation with a probiotic consortium Lactobacillus delbrueckii ssp. lactis, L. delbrueckii ssp. bulgaricus and Streptococcus thermophilus].}, journal = {Revista Argentina de microbiologia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ram.2024.02.002}, pmid = {38575495}, issn = {0325-7541}, abstract = {In recent years the relationship between the intestinal microbiota, the host and chronic non-communicable diseases has brought interest into the study of its formation and maintenance in the host. Lactic acid bacteria (BAL) are Gram-positive bacteria with probiotic activity, which have been associated with many health benefits, such as decreased body fat mass and lower risk of type II diabetes mellitus. One of the main colonization mechanisms and bacteria survival strategies is the production of biofilms and the use of prebiotics as substrates to achieve a balance within intestinal microbiota. However, there is not enough evidence to demonstrate the biofilm formation in the presence of agave fructans (AF). This study aimed to evaluate in vitro the biofilm formation in a consortium of lactic acid bacteria: Lactobacillus delbrueckii ssp. lactis, Lactobacillus delbrueckii ssp. bulgaricus y Streptococcus thermophilus in the presence of AF at different concentrations: 0%, 0,1%, 4%, 8% y 16%. The addition of 0,1% of AF correlates with the best capacity for biofilm formation. The findings imply the possibility of modulating the biofilm formation of lactic acid bacteria with AF. These results can contribute positively to the host, by generating intestinal homeostasis, colonization resistance, stability to food digestion and chemical modifications of drugs and carry out beneficial functions to the health.}, } @article {pmid38575095, year = {2024}, author = {Liu, W and Qian, J and Ding, H and Li, J and Liu, J and Zhou, W}, title = {Synergistic interactions of light and dark biofilms in rotating algal biofilm system for enhanced aquaculture wastewater treatment.}, journal = {Bioresource technology}, volume = {400}, number = {}, pages = {130654}, doi = {10.1016/j.biortech.2024.130654}, pmid = {38575095}, issn = {1873-2976}, abstract = {Aquaculture wastewater management is critical for environmental sustainability. This study investigates the synergistic interactions between light and dark biofilms with a Rotating Algal Biofilm (RAB) system for effective aquaculture wastewater treatment. The RAB system, optimized with a 5-day harvest time and 12-hour hydraulic retention time, demonstrated superior biomass productivity (3.3 g m[-2] d[-1]) and total ammoniacal nitrogen removal (82.3 %). Comparative analysis of light and dark biofilms revealed their complementary roles, with the light side exhibiting higher carbon assimilation and nutrient removal efficiencies, while the dark side contributed significantly to denitrification and phosphorus removal. Microbial community analysis highlighted the dominance of key bacterial genera such as Haliangium, Methyloversatilis and Comamonadaceae, along with the algal genus Chlorella, indicating their crucial roles in nutrient cycling. This study provides insights into the operational dynamics of RAB system for sustainable aquaculture wastewater treatment.}, } @article {pmid38573831, year = {2024}, author = {Machado, MAM and Chapartegui-González, I and Castro, VS and Figueiredo, EES and Conte-Junior, CA and Torres, AG}, title = {Biofilm-producing Escherichia coli O104: H4 overcomes bile salts toxicity by expressing virulence and resistance proteins.}, journal = {Letters in applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/lambio/ovae032}, pmid = {38573831}, issn = {1472-765X}, abstract = {We investigated bile salts' ability to induce phenotypic changes in biofilm production and protein expression of pathogenic Escherichia coli strains. For this purpose, 82 pathogenic E. coli strains isolated from humans (n = 70), and animals (n = 12), were examined for their ability to form biofilms in the presence or absence of bile salts. We also identified bacterial proteins expressed in response to bile salts using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-electrophoresis) and Liquid Chromatography-Mass Spectrometry (LC-MS/MS). Lastly, we evaluated the ability of these strains to adhere to Caco-2 epithelial cells in the presence of bile salts. Regarding biofilm formation, two strains isolated from an outbreak in Republic of Georgia in 2009 were the only ones that showed a high and moderate capacity to form biofilm in the presence of bile salts. Further, we observed that those isolates, when in the presence of bile salts, expressed different proteins identified as outer membrane proteins (i.e. OmpC), and resistance to adverse growth conditions (i.e. F0F1, HN-S, and L7/L12). We also found that these isolates exhibited high adhesion to epithelial cells in the presence of bile salts. Together, these results contribute to the phenotypic characterization of E. coli O104: H4 strains.}, } @article {pmid38573741, year = {2024}, author = {Padaga, SG and Bhatt, H and Ch, S and Paul, M and Itoo, AM and Ghosh, B and Roy, S and Biswas, S}, title = {Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c18061}, pmid = {38573741}, issn = {1944-8252}, abstract = {Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.}, } @article {pmid38572100, year = {2024}, author = {Fan, D and Liu, X and Ren, Y and Luo, Z and Li, Y and Dong, J and Wegner, SV and Chen, F and Zeng, W}, title = {Harnessing antimicrobial peptide-coupled photosensitizer to combat drug-resistant biofilm infections through enhanced photodynamic therapy.}, journal = {Acta pharmaceutica Sinica. B}, volume = {14}, number = {4}, pages = {1759-1771}, pmid = {38572100}, issn = {2211-3835}, abstract = {Bacterial biofilm-associated infection was one of the most serious threats to human health. However, effective drugs for drug-resistance bacteria or biofilms remain rarely reported. Here, we propose an innovative strategy to develop a multifunctional antimicrobial agent with broad-spectrum antibacterial activity by coupling photosensitizers (PSs) with antimicrobial peptides (AMPs). This strategy capitalizes on the ability of PSs to generate reactive oxygen species (ROS) and the membrane-targeting property of AMPs (KRWWKWIRW, a peptide screened by an artificial neural network), synergistically enhancing the antimicrobial activity. In addition, unlike conventional aggregation-caused quenching (ACQ) photosensitizers, aggregation-induced emission (AIE) PSs show stronger fluorescence emission in the aggregated state to help visualize the antibacterial mechanism. In vitro antibacterial experiments demonstrated the excellent killing effects of the developed agent against both Gram-positive (G[+]) and Gram-negative (G[-]) bacteria. The bacterial-aggregations induced ability enhanced the photoactivatable antibacterial activity against G[-] bacteria. Notably, it exhibited a significant effect on destroying MRSA biofilms. Moreover, it also showed remarkable efficacy in treating wound infections in mice in vivo. This multifunctional antimicrobial agent holds significant potential in addressing the challenges posed by bacterial biofilm-associated infections and drug-resistant bacteria.}, } @article {pmid38570017, year = {2024}, author = {Hamion, G and Aucher, W and Mercier, A and Tewes, F and Menard, M and Bertaux, J and Girardot, M and Imbert, C}, title = {Insights into betulinic acid as a promising molecule to fight the interkingdom biofilm Staphylococcus aureus-Candida albicans.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {107166}, doi = {10.1016/j.ijantimicag.2024.107166}, pmid = {38570017}, issn = {1872-7913}, abstract = {The demand for antibiofilm molecules has increased for several years due to their potential to fight biofilm-associated infections such as those including the interkingdom Staphylococcus aureus - Candida albicans occurring in clinical settings worldwide. Recently, we have identified a pentacyclic triterpenoid compound identified as betulinic acid (BA) from invasive macrophytes with interesting antibiofilm properties. Our study aimed at providing insights into the mechanism of action of BA against the clinically relevant bi-species S. aureus-C. albicans biofilms. Microscopy examinations, flow cytometry and crystal violet assays confirmed that BA was effective for damaging mature S. aureus-C. albicans biofilms or inhibiting their formation, reducing biofilm biomass by 70% on average and without microbicidal activity. Results suggested an action of BA on cell membranes, inducing changes in properties such as composition, hydrophobicity and fluidity as observed in C. albicans, which may hinder the early adhesion step, the biofilm growth and the physical interactions of both microbial species. Further results of real-time PCR argued in favor of a reduction of S. aureus-C. albicans physical interaction due to BA by the modulation of biofilm-related gene expression as observed in early stages of biofilm formation. This study revealed the potential of BA as candidate agent for the prevention and treatment of S. aureus-C. albicans biofilm-related infections.}, } @article {pmid38569307, year = {2024}, author = {Yu, Z and Qiu, D and Zhou, T and Zeng, L and Yan, C}, title = {Biofilm enhances the interactive effects of microplastics and oxytetracycline on zebrafish intestine.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {270}, number = {}, pages = {106905}, doi = {10.1016/j.aquatox.2024.106905}, pmid = {38569307}, issn = {1879-1514}, abstract = {The enhanced adsorption of pollutants on biofilm-developed microplastics has been proved in many studies, but the ecotoxicological effects of biofilm-developed microplastics on organisms are still unclear. In this study, adult zebrafish were exposed to original microplastics, biofilm-developed microplastics, original microplastics absorbed with oxytetracycline (OTC), and biofilm-developed microplastics absorbed with OTC for 30 days. The intestinal histological damage, intestinal biomarker response, gut microbiome and antibiotic resistance genes (ARGs) profile of zebrafish were measured to explore the roles of biofilm in the effects of microplastics. The results showed that biofilm-developed microplastics significantly increased the number of goblet cells in intestinal epithelium compared with the control group. The biofilm-developed microplastics also induced the oxidative response in the zebrafish intestines, and biofilm changed the response mode in the combined treatment with OTC. Additionally, the biofilm-developed microplastics caused intestinal microbiome dysbiosis, and induced the abundance of some pathogenic genera increasing by several times compared with the control group and the original microplastics treatments, regardless of OTC adsorption. Furthermore, the abundance of ARGs in biofilm-developed microplastics increased significantly compared with the control and the original microplastic treatments. This study emphasized the significant influence and unique role of biofilm in microplastic studies.}, } @article {pmid38565849, year = {2024}, author = {Cao, L and Tan, J and Zhang, Z and Lin, B and Mu, Y and Jiang, M and Jiang, Y and Huang, X and Han, L}, title = {Discovery of Antifungal Norsesquiterpenoids from a Soil-Derived Streptomyces microflavus: Targeting Biofilm Formation and Synergistic Combination with Amphotericin B against Yeast-like Fungi.}, journal = {Journal of agricultural and food chemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.jafc.3c08707}, pmid = {38565849}, issn = {1520-5118}, abstract = {Thirty-five norsesquiterpenoids were isolated from the fermentation broth of Streptomyces microflavus from the forest soil of Ailaoshan in China. The structures of new compounds (1-5, 10-26) were elucidated by comprehensive spectroscopic analysis including data from experimental and calculated ECD spectra, as well as Mosher's reagent derivatives method. Norsesquiterpenoids showed different levels of antifungal activity with MIC80 values ranging from 25 to 200 μg/mL against Candida albicans, Candida parapsilosis, and Cryptococcus neoformans. The combining isolated norsesquiterpenoids with amphotericin B resulted in a synergistic interaction against test yeast-like fungi with a fractional inhibitory concentration index < 0.5. Compound 33 significantly inhibited biofilm formation and destroyed the preformed biofilm of fungi. Moreover, 33 downregulated the expression of adhesion-related genes HWP1, ALS1, ALS3, ECE1, EAP1, and BCR1 to inhibit the adhesion of C. albicans. Findings from the current study highlight the potential usage of norsesquiterpenoids from soil-derived Streptomyces for antifungal leads discovery.}, } @article {pmid38565843, year = {2024}, author = {Brar, NK and Dhariwal, A and Åmdal, HA and Junges, R and Salvadori, G and Baker, JL and Edlund, A and Petersen, FC}, title = {Exploring ex vivo biofilm dynamics: consequences of low ampicillin concentrations on the human oral microbiome.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {37}, pmid = {38565843}, issn = {2055-5008}, abstract = {Prolonged exposure to antibiotics at low concentration can promote processes associated with bacterial biofilm formation, virulence and antibiotic resistance. This can be of high relevance in microbial communities like the oral microbiome, where commensals and pathogens share a common habitat and where the total abundance of antibiotic resistance genes surpasses the abundance in the gut. Here, we used an ex vivo model of human oral biofilms to investigate the impact of ampicillin on biofilm viability. The ecological impact on the microbiome and resistome was investigated using shotgun metagenomics. The results showed that low concentrations promoted significant shifts in microbial taxonomic profile and could enhance biofilm viability by up to 1 to 2-log. For the resistome, low concentrations had no significant impact on antibiotic resistance gene (ARG) diversity, while ARG abundance decreased by up to 84%. A positive correlation was observed between reduced microbial diversity and reduced ARG abundance. The WHO priority pathogens Streptococcus pneumoniae and Staphylococcus aureus were identified in some of the samples, but their abundance was not significantly altered by ampicillin. Most of the antibiotic resistance genes that increased in abundance in the ampicillin group were associated with streptococci, including Streptococcus mitis, a well-known potential donor of ARGs to S. pneumoniae. Overall, the results highlight the potential of using the model to further our understanding of ecological and evolutionary forces driving antimicrobial resistance in oral microbiomes.}, } @article {pmid38564677, year = {2024}, author = {Weaver, AA and Jia, J and Cutri, AR and Madukoma, CS and Vaerewyck, CM and Bohn, PW and Shrout, JD}, title = {Alkyl quinolones mediate heterogeneous colony biofilm architecture that improves community-level survival.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0009524}, doi = {10.1128/jb.00095-24}, pmid = {38564677}, issn = {1098-5530}, abstract = {Bacterial communities exhibit complex self-organization that contributes to their survival. To better understand the molecules that contribute to transforming a small number of cells into a heterogeneous surface biofilm community, we studied acellular aggregates, structures seen by light microscopy in Pseudomonas aeruginosa colony biofilms using light microscopy and chemical imaging. These structures differ from cellular aggregates, cohesive clusters of cells important for biofilm formation, in that they are visually distinct from cells using light microscopy and are reliant on metabolites for assembly. To investigate how these structures benefit a biofilm community we characterized three recurrent types of acellular aggregates with distinct geometries that were each abundant in specific areas of these biofilms. Alkyl quinolones (AQs) were essential for the formation of all aggregate types with AQ signatures outside the aggregates below the limit of detection. These acellular aggregates spatially sequester AQs and differentiate the biofilm space. However, the three types of aggregates showed differing properties in their size, associated cell death, and lipid content. The largest aggregate type co-localized with spatially confined cell death that was not mediated by Pf4 bacteriophage. Biofilms lacking AQs were absent of localized cell death but exhibited increased, homogeneously distributed cell death. Thus, these AQ-rich aggregates regulate metabolite accessibility, differentiate regions of the biofilm, and promote survival in biofilms.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen with the ability to cause infection in the immune-compromised. It is well established that P. aeruginosa biofilms exhibit resilience that includes decreased susceptibility to antimicrobial treatment. This work examines the self-assembled heterogeneity in biofilm communities studying acellular aggregates, regions of condensed matter requiring alkyl quinolones (AQs). AQs are important to both virulence and biofilm formation. Aggregate structures described here spatially regulate the accessibility of these AQs, differentiate regions of the biofilm community, and despite their association with autolysis, correlate with improved P. aeruginosa colony biofilm survival.}, } @article {pmid38564153, year = {2024}, author = {K, S and Nechikkadan, S and Theresa, M and Krishnankutty, RE}, title = {ZnO nanoparticles induced biofilm formation in Klebsiella pneumoniae and Staphylococcus aureus at sub-inhibitory concentrations.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {38564153}, issn = {1874-9356}, abstract = {Biofilm formation by the pathogenic bacteria generates a serious threat to the public health as it can increase the virulence potential, resistance to drugs, and escape from the host immune response mechanisms. Among the environmental factors that influence the biofilm formation, there are only limited reports available on the role of antimicrobial agents. During the antimicrobial drug administration or application for any purpose, the microbial population can expect to get exposed to the sub-minimum inhibitory concentration (sub-MIC) of the drug which will have an unprecedented impact on microbial responses. Hence, the study has been conducted to investigate the effects of sub-MIC levels of zinc oxide nanoparticles (ZnO NPs) on the biofilm formation of Klebsiella pneumoniae and Staphylococcus aureus. Here, the selected bacteria were primarily screened for the biofilm formation by using the Congo red agar method, and their susceptibility to ZnO NPs was also evaluated. Quantitative difference in biofilm formation by the selected organisms in the presence of ZnO NPs at the sub-MIC level was further carried out by using the microtiter plate-crystal violet assay. Further, the samples were subjected to atomic force microscopy (AFM) analysis to evaluate the properties and pattern of the biofilm modulated under the experimental conditions used. From these, the organisms treated with sub-MIC levels of ZnO NPs were found to have enhanced biofilm formation when compared with the untreated sample. Also, no microbial growth could be observed for the samples treated with the minimum inhibitory concentration (MIC) of ZnO NPs. The results observed in the study provide key insights into the impact of nanomaterials on clinically important microorganisms which demands critical thinking on the antimicrobial use of nanomaterials.}, } @article {pmid38564110, year = {2024}, author = {Ben-Amram, H and Azrad, M and Cohen-Assodi, J and Sharabi-Nov, A and Edelstein, S and Agay-Shay, K and Peretz, A}, title = {Biofilm Formation by Hospital-Acquired Resistant Bacteria Isolated from Respiratory Samples.}, journal = {Journal of epidemiology and global health}, volume = {}, number = {}, pages = {}, pmid = {38564110}, issn = {2210-6014}, abstract = {BACKGROUND: Hospital-acquired resistant infections (HARI) are infections, which develop 48 h or more after admission to a healthcare facility. HARI pose a considerably acute challenge, due to limited treatment options. These infections are associated bacterial biofilms, which act as a physical barrier to diverse external stresses, such as desiccation, antimicrobials and biocides. We assessed the influence of multiple factors on biofilm production by HARI -associated bacteria.

METHODS: Bacteria were isolated from samples of patients with respiratory HARI who were hospitalized during 2020-2022 in north Israel. Following antibiotic susceptibility testing by disc diffusion or broth microdilution, biofilm formation capacities of resistant bacteria (methicillin-resistant staphylococcus aureus, extended spectrum beta-lactamase-producing Escherichia coli and Klebsiela pneumonia, and multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii) was assessed using the crystalline violet staining method. Data regarding season, time to infection, bacterial species, patient age and gender, year, and medical department were collected from the patient medical records.

RESULTS: Among the 226 study isolates, K. pneumonia was the most prevalent (35.4%) bacteria, followed by P. aeruginosa (23.5%), and methicillin-resistant staphylococcus aureus (MRSA) (21.7%). A significantly higher rate of HARI was documented in 2022 compared to 2020-2021. The majority of isolates (63.3%) were strong biofilm producers, with K. pneumonia (50.3%) being most dominant, followed by P. aeruginosa (29.4%). Biofilm production strength was significantly affected by seasonality and hospitalization length, with strong biofilm production in autumn and in cases where hospitalization length exceeded 30 days.

CONCLUSION: Biofilm production by HARI bacteria is influenced by bacterial species, season and hospitalization length.}, } @article {pmid38562404, year = {2024}, author = {Wang, Y and Li, C and Zhang, H and Chi, Y and Cai, Y}, title = {The Potentiation Activity of Azithromycin in Combination with Colistin or Levofloxacin Against Pseudomonas aeruginosa Biofilm Infection.}, journal = {Infection and drug resistance}, volume = {17}, number = {}, pages = {1259-1266}, pmid = {38562404}, issn = {1178-6973}, abstract = {OBJECTIVE: Pseudomonas aeruginosa (PA) often displays drug resistance and biofilm-mediated adaptability. Here, we aimed to evaluate the antibiofilm efficacy of azithromycin-based combination regimens.

METHODS: Minimum inhibitory concentrations (MICs), minimal biofilm eradication concentrations (MBECs), and MBEC-combination of azithromycin, colistin, amikacin, and levofloxacin to bioluminescent strain PAO1 and carbapenem-resistant PAO1 (CRPAO1) were assessed. An animal biofilm infection model was established and detected using a live animal bio-photonic imaging system.

RESULTS: In vitro, PAO1 and CRPAO1 were susceptible to colistin, amikacin, and levofloxacin, while they were unsusceptible to azithromycin. The combinations based on azithromycin have no synergistic effect on biofilm in vitro. In vivo, azithromycin plus colistin or levofloxacin could shorten the PAO1 biofilm eradication time, which totally eradicates the biofilm in all mice on the 8[th] or 6[th] day, while monotherapy only eradicate biofilm in 70% or 80% mice on the 8[th] day. For CRPAO1 biofilm, only azithromycin-colistin combination and colistin monotherapy eradicated the bacteria in 60% and 40% of mice at the 6[th] day.

CONCLUSION: Azithromycin-based combinations containing levofloxacin or colistin had no synergistic effect in vitro, and they are promising for clinical applications due to the good synergistic activity against PAO1 biofilms in vivo.}, } @article {pmid38561125, year = {2024}, author = {Castagnini, D and Palma, K and Jara-Wilde, J and Navarro, N and González, MJ and Toledo, J and Canales-Huerta, N and Scavone, P and Härtel, S}, title = {Proteus mirabilis biofilm expansion microscopy yields over 4-fold magnification for super-resolution of biofilm structure and subcellular DNA organization.}, journal = {Journal of microbiological methods}, volume = {220}, number = {}, pages = {106927}, doi = {10.1016/j.mimet.2024.106927}, pmid = {38561125}, issn = {1872-8359}, abstract = {Bacterial biofilms form when bacteria attach to surfaces and generate an extracellular matrix that embeds and stabilizes a growing community. Detailed visualization and quantitative analysis of biofilm architecture by optical microscopy are limited by the law of diffraction. Expansion Microscopy (ExM) is a novel Super-Resolution technique where specimens are physically enlarged by a factor of ∼4, prior to observation by conventional fluorescence microscopy. ExM requires homogenization of rigid constituents of biological components by enzymatic digestion. We developed an ExM approach capable of expanding 48-h old Proteus mirabilis biofilms 4.3-fold (termed PmbExM), close to the theoretic maximum expansion factor without gross shape distortions. Our protocol, based on lytic and glycoside-hydrolase enzymatic treatments, degrades rigid components in bacteria and extracellular matrix. Our results prove PmbExM to be a versatile and easy-to-use Super-Resolution approach for enabling studies of P. mirabilis biofilm architecture, assembly, and even intracellular features, such as DNA organization.}, } @article {pmid38561094, year = {2024}, author = {Breen, SKJ and Harper, M and López-Causapé, C and Rogers, KE and Tait, JR and Smallman, TR and Lang, Y and Lee, WL and Zhou, J and Zhang, Y and Bulitta, JB and Nation, RL and Oliver, A and Boyce, JD and Landersdorfer, CB}, title = {Synergistic effects of inhaled aztreonam plus tobramycin on hypermutable cystic fibrosis Pseudomonas aeruginosa isolates in a dynamic biofilm model evaluated by mechanism-based modeling and whole genome sequencing.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {107161}, doi = {10.1016/j.ijantimicag.2024.107161}, pmid = {38561094}, issn = {1872-7913}, abstract = {Hypermutable Pseudomonas aeruginosa strains are highly prevalent in chronic lung infections of patients with cystic fibrosis (CF). Acute exacerbations of these infections have limited treatment options. This study aimed to investigate inhaled aztreonam and tobramycin against clinical hypermutable P. aeruginosa strains using the CDC dynamic in vitro biofilm reactor (CBR), mechanism-based mathematical modeling (MBM) and genomic studies. Two CF multidrug-resistant strains were investigated in a 168h CBR (n=2 biological replicates). Regimens were inhaled aztreonam (75 mg 8-hourly) and tobramycin (300 mg 12-hourly) in monotherapies and combination. The simulated pharmacokinetic profiles of aztreonam and tobramycin (t1/2=3h) were based on published lung fluid concentrations in patients with CF. Total viable and resistant counts were determined for planktonic and biofilm bacteria. MBM of total and resistant bacterial counts, and whole genome sequencing were completed. Both isolates showed reproducible bacterial regrowth and resistance amplification for the monotherapies by 168h. The combination performed synergistically, with minimal resistant subpopulations compared to the respective monotherapies at 168h. Mechanistic synergy appropriately described the antibacterial effects of the combination regimen in the MBM. Genomic analysis of colonies recovered from monotherapy regimens indicated noncanonical resistance mechanisms were likely responsible for treatment failure. The combination of aztreonam and tobramycin was required to suppress regrowth and resistance of planktonic and biofilm bacteria in all biological replicates of both hypermutable multidrug-resistant P. aeruginosa CF isolates. The developed MBM could be utilized for future investigations of this promising inhaled combination.}, } @article {pmid38559352, year = {2024}, author = {Manohar, P and Loh, B and Turner, D and Tamizhselvi, R and Mathankumar, M and Elangovan, N and Nachimuthu, R and Leptihn, S}, title = {In vitro and in vivo evaluation of the biofilm-degrading Pseudomonas phage Motto, as a candidate for phage therapy.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1344962}, pmid = {38559352}, issn = {1664-302X}, abstract = {Infections caused by Pseudomonas aeruginosa are becoming increasingly difficult to treat due to the emergence of strains that have acquired multidrug resistance. Therefore, phage therapy has gained attention as an alternative to the treatment of pseudomonal infections. Phages are not only bactericidal but occasionally show activity against biofilm as well. In this study, we describe the Pseudomonas phage Motto, a T1-like phage that can clear P. aeruginosa infections in an animal model and also exhibits biofilm-degrading properties. The phage has a substantial anti-biofilm activity against strong biofilm-producing isolates (n = 10), with at least a twofold reduction within 24 h. To demonstrate the safety of using phage Motto, cytotoxicity studies were conducted with human cell lines (HEK 293 and RAW 264.7 macrophages). Using a previously established in vivo model, we demonstrated the efficacy of Motto in Caenorhabditis elegans, with a 90% survival rate when treated with the phage at a multiplicity of infection of 10.}, } @article {pmid38559351, year = {2024}, author = {Liu, H and Ma, J and Yang, P and Geng, F and Li, X and Lü, J and Wang, Y}, title = {Comparative analysis of biofilm characterization of probiotic Escherichia coli.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1365562}, doi = {10.3389/fmicb.2024.1365562}, pmid = {38559351}, issn = {1664-302X}, abstract = {Biofilms are thought to play a vital role in the beneficial effects of probiotic bacteria. However, the structure and function of probiotic biofilms are poorly understood. In this work, biofilms of Escherichia coli (E. coli) Nissle 1917 were investigated and compared with those of pathogenic and opportunistic strains (E. coli MG1655, O157:H7) using crystal violet assay, confocal laser scanning microscopy, scanning electron microscopy and FTIR microspectroscopy. The study revealed significant differences in the morphological structure, chemical composition, and spatial heterogeneity of the biofilm formed by the probiotic E. coli strain. In particular, the probiotic biofilm can secrete unique phospholipid components into the extracellular matrix. These findings provide new information on the morphology, architecture and chemical heterogeneity of probiotic biofilms. This information may help us to understand the beneficial effects of probiotics for various applications.}, } @article {pmid38558539, year = {2024}, author = {Fan, J and Dong, Y and Sun, Y and Ji, Y and Feng, J and Yan, P and Zhu, Y}, title = {Mucus and Biofilm Penetrating Nanoplatform as an Ultrasound-Induced Free Radical Initiator for Targeted Treatment of Helicobacter pylori Infection.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2400363}, doi = {10.1002/adhm.202400363}, pmid = {38558539}, issn = {2192-2659}, abstract = {Helicobacter pylori (H. pylori) infection is closely associated with the development of various gastric diseases. The effectiveness of current clinical antibiotic therapy is hampered by the rise of drug-resistant strains and the formation of H. pylori biofilm. This paper reports a sonodynamic nanocomposite PtCu3-PDA@AIPH@Fucoidan (PPAF), which consists of dopamine-modified inorganic sonosensitizers PtCu3, alkyl radicals (R•) generator AIPH and fucoidan, can penetrate the mucus layer, target H. pylori, disrupt biofilms, and exhibit excellent bactericidal ability. In vitro experiments demonstrate that PPAF exhibits excellent acoustic kinetic properties, generating a significant amount of reactive oxygen species (ROS) and oxygen-independent R• for sterilization under ultrasound stimulation. Simultaneously, the produced N2 can enhance the cavitation effect, aiding PPAF nanoparticles in penetrating the gastric mucus layer and disrupting biofilm integrity. This disruption allows more PPAF nanoparticles to bind to biofilm bacteria, facilitating the eradication of H. pylori. In vivo experiments demonstrated that ultrasound-stimulated PPAF exhibited significant antibacterial efficacy against H. pylori. Moreover, it effectively modulated the expression levels of inflammatory factors and maintained gastrointestinal microbiota stability when compared to the antibiotic treatment group. In summary, PPAF nanoparticles present a potential alternative to antibiotics, offering an effective and healthy option for treating H. pylori infection. This article is protected by copyright. All rights reserved.}, } @article {pmid38557720, year = {2024}, author = {Zulkarnaini, Z and Matsuura, N and Kanazawa, S and Honda, R and Yamamoto-Ikemoto, R}, title = {Optimizing start-up strategies for the two-inflow nitritation/anammox process: Influence on biofilm microbial community composition.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {89}, number = {6}, pages = {1583-1594}, pmid = {38557720}, issn = {0273-1223}, support = {JP18K19874//Japan Society for the Promotion of Science (JSPS) KAKENHI/ ; //Ministry of Higher Education and Research and Technology Indonesia/ ; }, abstract = {Low-energy nitrogen removal from ammonium-rich wastewater is crucial in preserving the water environment. A one-stage nitritation/anammox process with two inflows treating ammonium-containing wastewater, supplied from inside and outside the wound filter, is expected to stably remove nitrogen. Laboratory-scale reactors were operated using different start-up strategies; the first involved adding nitritation inoculum after anammox biomass formation in the filter, which presented a relatively low nitrogen removal rate (0.171 kg N/m[3] · d), at a nitrogen loading rate of 1.0 kg N/m[3] · d. Conversely, the second involved the gradual cultivation of anammox and nitritation microorganisms, which increased the nitrogen removal rate (0.276 kg N/m[3] · d). Furthermore, anammox (Candidatus Brocadia) and nitritation bacteria (Nitrosomonadaceae) coexisted in the biofilm formed on the filter surface. The abundance of nitritation bacteria (10.5%) in the reactor biofilm using the second start-up strategy was higher than that using the first (3.7%). Thus, the two-inflow nitritation/anammox process effectively induced habitat segregation using a suitable start-up strategy.}, } @article {pmid38557711, year = {2024}, author = {Walker, P and Nerenberg, R and Pizarro, G and Aybar, M and Pavissich, JP and González, B and Pastén, P}, title = {Nitrate increases the capacity of an aerobic moving-bed biofilm reactor (MBBR) for winery wastewater treatment.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {89}, number = {6}, pages = {1454-1465}, pmid = {38557711}, issn = {0273-1223}, support = {FONDECYT 1200984//Agencia Nacional de Investigación y Desarrollo/ ; PIA/BASAL FB0002//Agencia Nacional de Investigación y Desarrollo/ ; VINNOVA 05CTE01-10//Corporación de Fomento de la Producción/ ; }, abstract = {We used bench-scale tests and mathematical modeling to explore chemical oxygen demand (COD) removal rates in a moving-bed biofilm reactor (MBBR) for winery wastewater treatment, using either urea or nitrate as a nitrogen source. With urea addition, the COD removal fluxes ranged from 34 to 45 gCOD/m[2]-d. However, when nitrate was added, fluxes increased up to 65 gCOD/m[2]-d, twice the amount reported for aerobic biofilms for winery wastewater treatment. A one-dimensional biofilm model, calibrated with data from respirometric tests, accurately captured the experimental results. Both experimental and modelling results suggest that nitrate significantly increased MBBR capacity by stimulating COD oxidation in the deeper, oxygen-limited regions of the biofilm. Our research suggests that the addition of nitrate, or other energetic and broadly used electron acceptors, may provide a cost-effective means of covering peak COD loads in biofilm processes for winery or another industrial wastewater treatment.}, } @article {pmid38556224, year = {2024}, author = {Kumari, S and Das, S}, title = {Functional amyloid fibrils of biofilm-forming marine bacterium Pseudomonas aeruginosa PFL-P1 interact spontaneously with pyrene and augment the biodegradation.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {131266}, doi = {10.1016/j.ijbiomac.2024.131266}, pmid = {38556224}, issn = {1879-0003}, abstract = {Bacteria thrive in biofilms embedding in the three-dimensional extracellular polymeric substances (EPS). Functional Amyloid in Pseudomonas (Fap), a protein in EPS, efficiently sequesters polycyclic aromatic hydrocarbons (PAHs). Present study reports the characterization of Fap fibrils from Pseudomonas aeruginosa PFL-P1 and describes the interaction with pyrene to assess the impact on pyrene degradation. Overexpression of fap in E. coli BL21(DE3) cells significantly enhances biofilm formation (p < 0.0001) and amyloid production (p = 0.0002), particularly with pyrene. Defibrillated Fap analysis reveals FapC monomers and increased fibrillation with pyrene. Circular Dichroism (CD), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) unveil characteristic amyloid peaks and structural changes in Fap fibrils upon pyrene exposure. 3D-EEM analysis identifies a protein-like fluorophore in Fap fibrils, exhibiting pyrene-induced fluorescence quenching. Binding constants range from 5.23 to 7.78 M[-1], with ΔG of -5.10 kJ mol[-1] at 298 K, indicating spontaneous and exothermic interaction driven by hydrophobic forces. Exogenous Fap fibrils substantially increased the biofilm growth and pyrene degradation by P. aeruginosa PFL-P1 from 46 % to 64 % within 7 days (p = 0.0236). GC-MS identifies diverse metabolites, implying phthalic acid pathway in pyrene degradation. This study deepens insights into structural dynamics of Fap fibrils when exposed to pyrene, offering potential application in environmental bioremediation.}, } @article {pmid38555648, year = {2024}, author = {Pujarern, P and Klaophimai, A and Amornsettachai, P and Panyayong, W and Chuenjitkuntaworn, B and Rokaya, D and Suphangul, S}, title = {Efficacy of Biofilm Removal on the Dental Implant Surface by Sodium Bicarbonate and Erythritol Powder Airflow System.}, journal = {European journal of dentistry}, volume = {}, number = {}, pages = {}, doi = {10.1055/s-0044-1779424}, pmid = {38555648}, issn = {1305-7456}, abstract = {OBJECTIVE: Peri-implantitis is a common complication in implant therapy and it is one of the main contributing factors to implant failure. This can be prevented by regular maintenance with mechanical debridement. One of the recent mechanical debridement methods is air abrasion therapy using different abrasive powders. This study aimed to evaluate the two common abrasive powders of different sizes (sodium bicarbonate and erythritol) for their biofilm cleaning efficacy on dental implant surfaces.

MATERIALS AND METHODS:  In an in vitro setting, a total of 33 implants were divided into three groups: Group 1 (n =11) = no treatment; group 2 (n = 11) = air abrasion therapy treated group using a sodium bicarbonate powder (AIRFLOW Powder Classic Comfort, EMS Electro Medical Systems, Nyon, Switzerland); and group 3 (n = 11) = air abrasion therapy treated group using an erythritol powder (AIRFLOW Powder Plus, EMS Electro Medical Systems, Nyon, Switzerland). The implants in each group were subjected to biofilm formation, and group 2 and group 3 were treated with air abrasion therapy of two different powders having different sizes with the same settings. The particle sizes were sodium bicarbonate (40 µm) and erythritol (14µm). The surface characteristics of the dental implants in three groups were studied from a digital camera and under the scanning electron microscope at different magnifications. The comparison of biofilm-removal efficacy between the three groups was performed by using a one-way analysis of variance with post-hoc Dunnett's T3 test. A p-value less than 0.05 was chosen to indicate statistical significance.

RESULTS:  There were no statistical differences (p > 0.05) between the two powder-treated groups for the biofilm cleaning efficacy. However, both groups showed significantly better biofilm-cleaning efficacy than the control group (p < 0.05).

CONCLUSION:  This suggests that both powders are effective in removing biofilm from the implant surface under ideal conditions. However, there was no clear distinction between the cleaning potential of the two powders, as both performed in a similar manner.}, } @article {pmid38555642, year = {2024}, author = {Kriswandini, IL and Budi, HS and Justitia, FM}, title = {Examination of the Structure and Formation Streptococcus mutans Biofilm Induced by Glucose, Lactose, Soy Protein, and Iron.}, journal = {European journal of dentistry}, volume = {}, number = {}, pages = {}, doi = {10.1055/s-0043-1776121}, pmid = {38555642}, issn = {1305-7456}, abstract = {OBJECTIVE: Streptococcus mutans, the main causative agent of caries, have the ability to form biofilms on the surface of teeth. The availability of nutrients such as glucose, lactose, soy protein, and iron can influence S. mutans in biofilm formation. All four sources of nutrients have been shown to increase the formation of S. mutans biofilms. The purpose of this study was to determine the structure and thickness of S. mutans biofilms induced by glucose, lactose, soy protein, and iron.

MATERIALS AND METHODS:  This experimental laboratory study aimed to examine the formation of biofilm structures (chemical elements) and determine the thickness of S. mutans biofilms induced by glucose, lactose, soy protein, and iron. The structures (chemical elements) were examined using scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) analysis. Confocal laser scanning microscopy (CLSM) was used to determine the thickness of S. mutans biofilms with an Olympus FV1000 microscope, and the findings were analyzed using Olympus Fluoview Ver. 4.2a software.

RESULTS:  It was established that the results of SEM-EDX examination of the structure of S. mutans biofilms induced by glucose had oxygen (O) as the dominant chemical element (30.24 w%); lactose reported oxygen (O) as the dominant element (29.65 w%); soy protein had carbon (C) as the dominant element (34.31 w%); and iron showed oxygen (O) as the dominant element (32.51 w%). The thickness (measured by the CLSM examination) of biofilms induced by glucose, lactose, soy protein, and iron were 17,666, 12,666, 18,000, and 15,666 nm, respectively.

CONCLUSION:  The structure of S. mutans biofilms induced by glucose, lactose, and iron contain the following elements in amounts from the highest to lowest: O, C, N, P, and S; the biofilm produced by S. mutans induced by soy protein in amounts from the highest to lowest comprised the elements: C, O, N, S, and P. The S. mutans biofilms induced by soy protein had the maximum thickness, followed by those induced by glucose, iron, and lactose.}, } @article {pmid38552829, year = {2024}, author = {Zhao, ZC and Fan, SQ and Lu, Y and Tan, X and Liu, LY and Wang, XW and Liu, BF and Xing, DF and Ren, NQ and Xie, GJ}, title = {Deep insights into the biofilm formation mechanism and nitrogen-transformation network in a nitrate-dependent anaerobic methane oxidation biofilm.}, journal = {Environmental research}, volume = {252}, number = {Pt 1}, pages = {118810}, doi = {10.1016/j.envres.2024.118810}, pmid = {38552829}, issn = {1096-0953}, abstract = {Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) process offers a promising solution for simultaneously achieving methane emissions reduction and efficient nitrogen removal in wastewater treatment. Although nitrogen removal at a practical rate has been achieved by n-DAMO biofilm process, the mechanisms of biofilm formation and nitrogen transformation remain to be elucidated. In this study, n-DAMO biofilms were successfully developed in the membrane aerated moving bed biofilm reactor (MAMBBR) and removed nitrate at a rate of 159 mg NO3[-]-N L[-1] d[-1]. The obvious increase in the content of extracellular polymeric substances (EPS) indicated that EPS production was important for biofilm development. n-DAMO microorganisms dominated the microbial community, and n-DAMO bacteria were the most abundant microorganisms. However, the expression of biosynthesis genes for proteins and polysaccharides encoded by n-DAMO archaea was significantly more active compared to other microorganisms, suggesting the central role of n-DAMO archaea in EPS production and biofilm formation. In addition to nitrate reduction, n-DAMO archaea were revealed to actively express dissimilatory nitrate reduction to ammonium and nitrogen fixation. The produced ammonium was putatively converted to dinitrogen gas through the joint function of n-DAMO archaea and n-DAMO bacteria. This study revealed the biofilm formation mechanism and nitrogen-transformation network in n-DAMO biofilm systems, shedding new light on promoting the application of n-DAMO process.}, } @article {pmid38552580, year = {2024}, author = {He, Z and Li, Y and Yang, L and Li, Y and Cao, D and Wang, S and Xie, J and Yan, X}, title = {Sunlight-triggered prebiotic nanomotors for inhibition and elimination of pathogen and biofilm in aquatic environment.}, journal = {Journal of colloid and interface science}, volume = {665}, number = {}, pages = {634-642}, doi = {10.1016/j.jcis.2024.03.163}, pmid = {38552580}, issn = {1095-7103}, abstract = {Pathogen contamination in drinking water sources causes waterborne infectious diseases, seriously threatening human health. Nowadays, stimuli-responsive self-propelled nanomotors are appealing therapeutic agents for antibacterial therapy in vivo. However, achieving water disinfection using these nanobots is still a great challenge. Herein, we report on prebiotic galactooligosaccharide-based nanomotors for sunlight-regulated water disinfection. The nanomotors can utilize galactooligosaccharide-based N-nitrosamines as sunlight-responsive fuels for the spontaneous production of antibacterial nitric oxide. Such a solar-to-chemical energy conversion would power the nanomotors for self-diffusiophoresis, which could promote the diffusion of the nanomotors in water and their penetration in the biofilm, significantly enhancing the inhibition and elimination of the pathogens and their biofilms in aquatic environments. After water treatments, the prebiotic-based residual disinfectants can be selectively utilized by beneficial bacteria to effectively relieve safety risks to the environment and human health. The low-energy-cost, green and potent antibacterial nanobots show promising potential in water disinfection.}, } @article {pmid38552483, year = {2024}, author = {Lu, Y and Liu, T and Hu, S and Yuan, Z and Dwyer, J and Akker, BVD and Lloyd, J and Guo, J}, title = {Coupling Partial Nitritation, Anammox and n-DAMO in a membrane aerated biofilm reactor for simultaneous dissolved methane and nitrogen removal.}, journal = {Water research}, volume = {255}, number = {}, pages = {121511}, doi = {10.1016/j.watres.2024.121511}, pmid = {38552483}, issn = {1879-2448}, abstract = {Anaerobic technologies with downstream autotrophic nitrogen removal have been proposed to enhance bioenergy recovery and transform a wastewater treatment plant from an energy consumer to an energy exporter. However, approximately 20-50 % of the produced methane is dissolved in the anaerobically treated effluent and is easily stripped into the atmosphere in the downstream aerobic process, contributing to the release of greenhouse gas emissions. This study aims to develop a solution to beneficially utilize dissolved methane to support high-level nitrogen removal from anaerobically treated mainstream wastewater. A novel technology, integrating Partial Nitritation, Anammox and Methane-dependent nitrite/nitrate reduction (i.e. PNAM) was demonstrated in a membrane-aerated biofilm reactor (MABR). With the feeding of ∼50 mg NH4[+]-N/L and ∼20 mg/L dissolved methane at a hydraulic retention time of 15 h, around 90 % of nitrogen and ∼100 % of dissolved methane can be removed together in the MABR. Microbial community characterization revealed that ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), anammox bacteria, nitrite/nitrate-dependent anaerobic methane oxidation microorganisms (n-DAMO bacteria and archaea) and aerobic methanotrophs co-existed in the established biofilm. Batch tests confirmed the active microbial pathways and showed that AOB, anammox bacteria and n-DAMO microbes were jointly responsible for the nitrogen removal, and dissolved methane was mainly removed by the n-DAMO process, with aerobic methane oxidation making a minor contribution. In addition, the established system was robust against dynamic changes in influent composition. The study provides a promising technology for the simultaneous removal of dissolved methane and nitrogen from domestic wastewater, which can support the transformation of wastewater treatment from an energy- and carbon-intensive process, to one that is energy- and carbon-neutral.}, } @article {pmid38551364, year = {2024}, author = {Zhao, E and Xiong, X and Li, X and Hu, H and Wu, C}, title = {Effect of Biofilm Forming on the Migration of Di(2-ethylhexyl)phthalate from PVC Plastics.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c09021}, pmid = {38551364}, issn = {1520-5851}, abstract = {Plastic additives, represented by plasticizers, are important components of plastic pollution. Biofilms inevitably form on plastic surfaces when plastic enters the aqueous environment. However, little is known about the effect of biofilms on plastic surfaces on the release of additives therein. In this study, PVC plastics with different levels of di(2-ethylhexyl)phthalate (DEHP) content were investigated to study the effect of biofilm growth on DEHP release. The presence of biofilms promoted the migration of DEHP from PVC plastics to the external environment. Relative to biofilm-free controls, although the presence of surface biofilm resulted in 0.8 to 11.6 times lower DEHP concentrations in water, the concentrations of the degradation product, monoethylhexyl phthalate (MEHP) in water, were 2.3 to 57.3 times higher. When the total release amounts of DEHP in the biofilm and in the water were combined, they were increased by 0.6-73 times after biofilm growth. However, most of the released DEHP was adsorbed in the biofilms and was subsequently degraded. The results of this study suggest that the biofilm as a new interface between plastics and the surrounding environment can affect the transport and transformation of plastic additives in the environment through barrier, adsorption, and degradation. Future research endeavors should aim to explore the transport dynamics and fate of plastic additives under various biofilm compositions as well as evaluate the ecological risks associated with their enrichment by biofilms.}, } @article {pmid38549371, year = {2024}, author = {Zhu, R and Stone, T and Wang, Y}, title = {The Role of Shear Rates on Amyloid Formation from Biofilm Peptides Phenol Soluble Modulins.}, journal = {Biophysical journal}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.bpj.2024.03.036}, pmid = {38549371}, issn = {1542-0086}, abstract = {Biofilms, microbial communities enclosed in the self-produced extracellular matrix, have a significant impact on human health, environment, and industry. The pathogen Staphylococcus aureus (S. aureus) is recognized as one of the most frequent causes of biofilm-related infections. Phenol soluble modulins (PSMs) serve as a crucial component, fortifying S. aureus biofilm matrix through self-assembly into amyloid fibrils, which enhances S. aureus colonization and resistance to antibiotics. However, the role of shear rate, one of the critical physiological factors within blood vessels, on the formation of PSM amyloids remains poorly understood. In this work, using a combination of thioflavin T fluorescence kinetic studies, circular dichroism spectrometry, and electron microscopy, we demonstrated that shear rates ranging from 150 s[-1] to 300 s[-1] accelerate fibrillation of PSMα1, α3, and α4 into amyloids, resulting in elongated amyloid structures. Furthermore, PSMα1, α3, and α4 predominantly self-assembled into amyloid fibers with a cross-α structure under shear conditions, deviating from the typical β-sheet configuration of PSM amyloids. These findings imply the role of shear rates within the bloodstream on enhancing PSM self-assembly that is associated with S. aureus biofilm formation.}, } @article {pmid38547720, year = {2024}, author = {Tan, J and Zhang, Z and Zheng, D and Mu, Y and Cao, B and Yang, J and Han, L and Huang, X}, title = {Structure-activity relationship and biofilm formation-related gene targets of oleanolic acid-type saponins from Pulsatilla chinensis against Candida albicans.}, journal = {Bioorganic chemistry}, volume = {146}, number = {}, pages = {107311}, doi = {10.1016/j.bioorg.2024.107311}, pmid = {38547720}, issn = {1090-2120}, abstract = {In the course of our investigations of antifungal natural products, the structure-activity relationship and antifungal activities of oleanolic acid-type saponins (1-28) from Pulsatilla chinensis against human and plant pathogenic fungi were elucidated. The analysis of structure-activity relationship of oleanolic acid-type saponins showed that the free carboxyl at C-28 was essential for their antifungal activities; the free hydroxyl group at the C-23 site of oleanolic acid-type saponins played a crucial role in their antifungal activities; the oligosaccharide chain at C-3 oleanolic acid-type saponins showed significant effects on antifungal efficacy and a disaccharide or trisaccharide moiety at position C-3 displayed optimal antifungal activity. The typical saponin pulchinenoside B3 (16, PB3) displayed satisfactory antifungal activity against human and plant pathogenic fungi, especially, C. albicans with an MIC value of 12.5 μg/mL. Furthermore, PB3 could inhibit the biofilm formation of C. albicans through downregulating the expression of the integrated network of biofilm formation-associated transcription factors (Bcr1 Efg1, Ndt80, Brg1, Rob1 and Tec1) and adhesion-related target genes (HWP1, ALS1, and ALS3). Meanwhile, we found that PB3 could effectively destroy the mature biofilm of C. albicans by the oxidative damage and inducing mitochondria-mediated apoptosis in cells.}, } @article {pmid38547415, year = {2024}, author = {Sequeira, SB and Myntti, MF and Lee, J and Mont, MA}, title = {An Overview of Research for the Application of a Novel Biofilm-Preventing Surgical Irrigation System for Total Joint Arthroplasty Procedures in Order to Reduce the Risk of Periprosthetic Infection.}, journal = {Surgical technology international}, volume = {44}, number = {}, pages = {}, pmid = {38547415}, issn = {1090-3941}, abstract = {Periprosthetic joint infection (PJI) is a serious postoperative complication in joint arthroplasty procedures that carries substantial morbidity and mortality associated with it. Several strategies have been developed both in the preoperative, perioperative, and postoperative periods to both combat and prevent the development of this devastating complication. Intraoperative irrigation is an important modality used during arthroplasty procedures prior to the implantation of final components that seeks to eradicate any biofilm formation. In this updated review, we discuss the XPERIENCE™ Advanced Surgical Irrigation solution (Next Science, Jacksonville, Florida) and the various completed, ongoing, and planned basic science and clinical investigations associated with it. Although there is already an impressive body of literature supporting its widespread utilization, future basic and clinical trials will continue to be performed to comprehensively characterize the effect this antimicrobial solution has on eliminating the risk of PJI following arthroplasty procedures.}, } @article {pmid38545796, year = {2024}, author = {Matoso, FB and Montagner, F and Grecca, FS and Rampelotto, PH and Kopper, PMP}, title = {Microbial composition and diversity in intraradicular biofilm formed in situ: New concepts based on next-generation sequencing.}, journal = {Molecular oral microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/omi.12463}, pmid = {38545796}, issn = {2041-1014}, abstract = {This study aimed to characterize the taxonomic composition of intraradicular multispecies biofilms (IMB) formed in situ in a model to reproduce clinical conditions. Twelve palatal roots of maxillary molars had its canals prepared. Two roots were randomly selected to sterility control. Ten intraoral prosthetic appliances with lateral slots were fabricated. The roots were positioned in the slots with the canal access open to the oral cavity. Eight volunteers wore the appliance for 21 days, and two wore it at two different time points. One root from each appliance was removed and stored at -20°C until DNA extraction and sequencing (n = 10). Biofilm was analyzed using next-generation sequencing and bioinformatics. The V4 hyper-variable region of the 16SrRNA gene was amplified and sequenced. For data analyses, the mothur pipeline was used for 16SrRNA processing, and subsequent analyses of the sequence dataset were performed in R using the Microbiome Analyst R package. The taxonomy-based analysis of bacterial communities identified 562 operational taxonomic units (OTUs), which belonged to 93 genera, 44 families, and 8 phyla. Bacterial colonization was different for each biofilm, and samples did not have the same group of bacteria. Alpha and beta diversity analysis revealed some general patterns of sample clustering. A core microbiome of prevalent OTUs and genera was identified. IMBs were heterogeneous when analyzed individually, but some diversity patterns were found after sample clustering. The experimental model seemed to reproduce the actual biofilm composition in endodontic infections, which suggests that it may be used to evaluate disinfection protocols.}, } @article {pmid38544898, year = {2024}, author = {Işlek Köklü, Z and Akkuş Süt, P and Eskihoran Üçüncüoğlu, E and Kalayci, S and Şahin, F}, title = {Detection and characterization of the Pichia manshurica biofilm on the traditionally produced homemade apple vinegar.}, journal = {Turkish journal of chemistry}, volume = {48}, number = {1}, pages = {76-84}, pmid = {38544898}, issn = {1300-0527}, abstract = {Pichia yeasts are capable of forming biofilms during vinegar production and causing spoilage in various beverages. In addition, there exists a significant likelihood of encountering yeast contamination which can prevent vinegar production. The present study investigates the detection and characterization of the Pichia manshurica (P. manshurica) biofilm on traditionally produced homemade apple vinegar. The unique characteristics of vinegar were analyzed with a focus on the constituent, known as the "mother of vinegar", whose composition is comprised of cellulosic biofilm and acetic acid bacteria, including Gluconobacter oxydans (G. oxydans) Briefly, P. manshurica was isolated from apple vinegar and characterized in terms of the effect of biofilm formation on the surface of the cellulosic film on vinegar production. Microbial identification of vinegar with/without contamination by P. manshurica was analyzed through MALDI-TOF mass spectrometry (MS), and biofilm was characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and crystal violet staining. Accordingly, MS spectrum of isolates was identified as G. oxydans and P. manshurica with a ratio of 2.01 and 1.94, respectively. The FTIR analysis indicated that the peaks within the range of 1150-900 cm[-1] revealed a high content of polysaccharide in P. manchuria-contaminated biofilm, which is attributed to the stretching vibration of C-C and C-O bonds. The spectral region from 2921.51 to 2853.71 cm[-1] exhibited the characteristic of lipids in bacterial cell walls and membranes. SEM images of bacterial biofilms revealed a three-dimensional network composed of ultrafine fibers with a ribbon-like shape; however, the condensed reticulated structure was observed in contaminated biofilms. The presence of two microbial populations was detected regarding the morphological analysis. Crystal violet staining of contaminated-cellulosic biofilms visualized bacterial and yeast colonization. Concisely, this study emphasizes that the proliferation of Pichia during apple fermentation has the potential to adversely affect the quality of the homemade vinegar, due to its distinct biofilm characteristics.}, } @article {pmid38544741, year = {2024}, author = {David, A and Louis, M and Tahrioui, A and Rodrigues, S and Labbé, C and Maillot, O and Barreau, M and Lesouhaitier, O and Cornelis, P and Chevalier, S and Bouffartigues, E}, title = {cmpX overexpression in Pseudomonas aeruginosa affects biofilm formation and cell morphology in response to shear stress.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100191}, pmid = {38544741}, issn = {2590-2075}, abstract = {UNLABELLED: Pseudomonas aeruginosa is an opportunistic pathogen causing chronic infections that are related to its ability to form biofilms. Mechanosensitive ion channels (Mcs) are cytoplasmic membrane proteins whose opening depends on a mechanical stress impacting the lipid bilayer. CmpX is a homologue of the small conductance MscS of Escherichia coli. The cmpX gene is part of a transcriptional cfrX-cmpX unit that is under the control of the cell envelope stress response ECF sigma factor SigX. CmpX was shown to regulate the activity of the hybrid sensor kinase PA1611 involved in the regulation of transition from a planktonic to a biofilm lifestyle. The deletion of cmpX leads to increased biofilm formation under static conditions. Herein, the effect of cmpX overexpression was investigated by confocal laser scanning microscopy in terms of biofilm formation and architecture, and matrix components production, in dynamic conditions. We show that overexpression of cmpX in P. aeruginosa leads to enhanced and altered biofilm architecture that seems to be associated to increased matrix components and the emergence of filamentous cells. These phenotypic alterations might occur potentially through a shear stress induced by the medium flow rate.

IMPORTANCE: CmpX is involved in biofilm formation and cell filamentation with regards to the medium flow.}, } @article {pmid38544331, year = {2024}, author = {Wang, C and Defoirdt, T and Rajkovic, A}, title = {The impact of indole and mucin on sporulation, biofilm formation and enterotoxin production in foodborne Clostridium perfringens.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxae083}, pmid = {38544331}, issn = {1365-2672}, abstract = {AIMS: Indole and mucin are compounds found in the host environment as they are produced by the host or by the host-associated microbiota. This study investigated whether indole and mucin impact C. perfringens growth and sporulation, as well as enterotoxin production and biofilm formation.

METHODS AND RESULTS: There was no impact on growth of C. perfringens for up to 400 µM indole and 240 mg/L mucin, and neither indole nor mucin affected sporulation. Reverse-transcriptase qPCR showed that mucin strongly upregulated the expression of C. perfringens enterotoxin (up to 121-fold increase), whereas indole had a much more modest effect (2-fold). This was also reflected in increased C. perfringens enterotoxin levels in mucin-treated C. perfringens (as assessed by a reversed passive latex agglutination assay). Finally, mucin and indole significanly increased biofilm formation of C. perfringens, although the effect size was relatively small (less than 1.5 fold).

CONCLUSION: These results indicate that C. perfringens can sense its presence in a host environment by responding to mucin and thereby markedly increased enterotoxin production.}, } @article {pmid38543751, year = {2024}, author = {Golosova, NN and Matveev, AL and Tikunova, NV and Khlusevich, YA and Kozlova, YN and Morozova, VV and Babkin, IV and Ushakova, TA and Zhirakovskaya, EV and Panina, EA and Ryabchikova, EI and Tikunov, AY}, title = {Bacteriophage vB_SepP_134 and Endolysin LysSte_134_1 as Potential Staphylococcus-Biofilm-Removing Biological Agents.}, journal = {Viruses}, volume = {16}, number = {3}, pages = {}, doi = {10.3390/v16030385}, pmid = {38543751}, issn = {1999-4915}, support = {122022100238-7//the Russian state-funded project for ICBFM SB RAS/ ; }, abstract = {Bacteria of the genus Staphylococcus are significant challenge for medicine, as many species are resistant to multiple antibiotics and some are even to all of the antibiotics we use. One of the approaches to developing new therapeutics to treat staphylococcal infections is the use of bacteriophages specific to these bacteria or the lytic enzymes of such bacteriophages, which are capable of hydrolyzing the cell walls of these bacteria. In this study, a new bacteriophage vB_SepP_134 (St 134) specific to Staphylococcus epidermidis was described. This podophage, with a genome of 18,275 bp, belongs to the Andhravirus genus. St 134 was able to infect various strains of 12 of the 21 tested coagulase-negative Staphylococcus species and one clinical strain from the Staphylococcus aureus complex. The genes encoding endolysin (LysSte134_1) and tail tip lysin (LysSte134_2) were identified in the St 134 genome. Both enzymes were cloned and produced in Escherichia coli cells. The endolysin LysSte134_1 demonstrated catalytic activity against peptidoglycans isolated from S. aureus, S. epidermidis, Staphylococcus haemolyticus, and Staphylococcus warneri. LysSte134_1 was active against S. aureus and S. epidermidis planktonic cells and destroyed the biofilms formed by clinical strains of S. aureus and S. epidermidis.}, } @article {pmid38543484, year = {2024}, author = {Rosa-Masegosa, A and Rodriguez-Sanchez, A and Gorrasi, S and Fenice, M and Gonzalez-Martinez, A and Gonzalez-Lopez, J and Muñoz-Palazon, B}, title = {Microbial Ecology of Granular Biofilm Technologies for Wastewater Treatment: A Review.}, journal = {Microorganisms}, volume = {12}, number = {3}, pages = {}, doi = {10.3390/microorganisms12030433}, pmid = {38543484}, issn = {2076-2607}, abstract = {Nowadays, the discharge of wastewater is a global concern due to the damage caused to human and environmental health. Wastewater treatment has progressed to provide environmentally and economically sustainable technologies. The biological treatment of wastewater is one of the fundamental bases of this field, and the employment of new technologies based on granular biofilm systems is demonstrating success in tackling the environmental issues derived from the discharge of wastewater. The granular-conforming microorganisms must be evaluated as functional entities because their activities and functions for removing pollutants are interconnected with the surrounding microbiota. The deep knowledge of microbial communities allows for the improvement in system operation, as the proliferation of microorganisms in charge of metabolic roles could be modified by adjustments to operational conditions. This is why engineering must consider the intrinsic microbiological aspects of biological wastewater treatment systems to obtain the most effective performance. This review provides an extensive view of the microbial ecology of biological wastewater treatment technologies based on granular biofilms for mitigating water pollution.}, } @article {pmid38543172, year = {2024}, author = {Qaralleh, H and Saghir, SAM and Al-Limoun, MO and Dmor, SM and Khleifat, K and Al-Ahmad, BEM and Al-Omari, L and Tabana, Y and Mothana, RA and Al-Yousef, HM and Alqahtani, AM}, title = {Effect of Matricaria aurea Essential Oils on Biofilm Development, Virulence Factors and Quorum Sensing-Dependent Genes of Pseudomonas aeruginosa.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {17}, number = {3}, pages = {}, doi = {10.3390/ph17030386}, pmid = {38543172}, issn = {1424-8247}, support = {RSP2024R119//The Researchers Supporting Program, King Saud University, Riyadh, Saudi Arabia/ ; }, abstract = {The emergence of drug-resistant microorganisms presents a substantial global public health threat. The increase in pathogens resistant to commonly prescribed antibiotics underscores the urgent requirement to explore alternative treatment strategies. This study adopts a novel approach by harnessing natural resources, specifically essential oils (EO), to combat bacterial pathogenicity. The primary aim of this research was to analyze the chemical composition of the aerial part of the Matricaria aurea (M. aureas) EO and evaluate its potential for inhibiting quorum sensing (QS) and disrupting biofilm formation in Pseudomonas aeruginosa (P. aeruginosa). The gas chromatography-mass spectrometry (GCMS) analysis unveiled that α-bisabolol oxide A constituted the predominant portion, comprising 64.8% of the total, with β-bisabolene at 6.3% and α-farnesene at 4.8% following closely behind. The antibiofilm efficacy was observed at concentrations of 0.3, 0.15, and 0.08 mg/mL, demonstrating negligible effects on cell viability. Furthermore, the EO from M. aurea effectively inhibited the formation of P. aeruginosa biofilms by diminishing aggregation, hydrophobicity, and swarming motility. Significantly, the EO treatment resulted in a conspicuous decrease in the production of pyocyanin, rhamnolipid, and extracellular polymeric substances (EPS), along with a reduction in the enzymatic activity of protease and chitinase. The EO effectively hindered QS by disrupting QS mechanisms, resulting in a marked decline in the secretion of N-Acyl homoserine lactone (AHL) molecules and the expression of phazA1 and aprA genes. This investigation offers compelling evidence supporting the potential of M. aurea EO as a promising therapeutic candidate for addressing infectious diseases induced by biofilm formation.}, } @article {pmid38543106, year = {2024}, author = {Campos, LAA and Neto, AFS and Scavuzzi, AML and Lopes, ACS and Santos-Magalhães, NS and Cavalcanti, IMF}, title = {Ceftazidime/Tobramycin Co-Loaded Chitosan-Coated Zein Nanoparticles against Antibiotic-Resistant and Biofilm-Producing Pseudomonas aeruginosa and Klebsiella pneumoniae.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {17}, number = {3}, pages = {}, doi = {10.3390/ph17030320}, pmid = {38543106}, issn = {1424-8247}, support = {88887311907/2018-00//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 408785/2022.5//National Council for Scientific and Technological Development/ ; 050427/2023-21//Universidade Federal de Pernambuco/ ; }, abstract = {This study aimed to co-encapsulate ceftazidime and tobramycin in zein nanoparticles coated with chitosan and to characterize and evaluate the antibacterial and antibiofilm activity against antibiotic-resistant Pseudomonas aeruginosa and Klebsiella pneumoniae. Zein nanoparticles, synthesized using the nanoprecipitation method, were characterized by their particle size (Ø), polydispersity index (PDI), zeta potential (ζ), pH, and encapsulation efficiency (%EE). The chitosan coating provided stability, and physicochemical analyses revealed chemical interactions, efficient drug encapsulation, and thermal stability. The release kinetics demonstrated controlled release in simulated gastric and intestinal pH. The antibacterial activity, assessed by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), indicated effectiveness against both pathogens. Antibiofilm assays, conducted using the crystal violet method, demonstrated the inhibition and eradication of biofilms. The chitosan-coated zein nanoparticles with CAZ and/or TOB exhibited Ø (315-335 nm), PDI (<0.2), ζ (+40 to +50 mV), pH (5), and %EE (>55%). Notably, the co-encapsulation formulation (CAZ-TOB-ZNP-CH) showed enhanced antibacterial and antibiofilm activities compared to the individual formulations. These findings suggest that the developed nanoparticles present a promising alternative for treating respiratory and intestinal infections caused by antibiotic-resistant and biofilm-producing P. aeruginosa and K. pneumoniae.}, } @article {pmid38542379, year = {2024}, author = {Houtak, G and Nepal, R and Bouras, G and Shaghayegh, G and Bennett, C and Finnie, J and Fenix, K and Psaltis, AJ and Wormald, PJ and Vreugde, S}, title = {Staphylococcus aureus Biofilm-Secreted Factors Cause Mucosal Damage, Mast Cell Infiltration, and Goblet Cell Hyperplasia in a Rat Rhinosinusitis Model.}, journal = {International journal of molecular sciences}, volume = {25}, number = {6}, pages = {}, doi = {10.3390/ijms25063402}, pmid = {38542379}, issn = {1422-0067}, support = {APP1196832//National Health and Medical Research Council/ ; University of Adelaide International Scholarships//University of Adelaide/ ; Top-up scholarship//The Hospital Research Foundation Group/ ; senior fellowship//Passe & Williams Foundation/ ; }, abstract = {Chronic rhinosinusitis (CRS) is an inflammatory condition of the sinonasal mucosa. Despite being a common health issue, the exact cause of CRS is yet to be understood. However, research suggests that Staphylococcus aureus, particularly in its biofilm form, is associated with the disease. This study aimed to investigate the impact of long-term exposure to secreted factors of Staphylococcus aureus biofilm (SABSFs), harvested from clinical isolates of non-CRS carrier and CRS patients, on the nasal mucosa in a rat model. Animals were randomised (n = 5/group) to receive daily intranasal instillations of 40 μL (200 μg/μL) SABSFs for 28 days or vehicle control. The sinonasal samples were analysed through histopathology and transcriptome profiling. The results showed that all three intervention groups displayed significant lymphocytic infiltration (p ≤ 0.05). However, only the SABSFs collected from the CRSwNP patient caused significant mucosal damage, mast cell infiltration, and goblet cell hyperplasia compared to the control. The transcriptomics results indicated that SABSFs significantly enriched multiple inflammatory pathways and showed distinct transcriptional expression differences between the control group and the SABSFs collected from CRS patients (p ≤ 0.05). Additionally, the SABSF challenges induced the expression of IgA and IgG but not IgE. This in vivo study indicates that long-term exposure to SABSFs leads to an inflammatory response in the nasal mucosa with increased severity for S. aureus isolated from a CRSwNP patient. Moreover, exposure to SABSFs does not induce local production of IgE.}, } @article {pmid38542256, year = {2024}, author = {Bravo, E and Arce, M and Ribeiro-Vidal, H and Herrera, D and Sanz, M}, title = {The Impact of Candida albicans in the Development, Kinetics, Structure, and Cell Viability of Biofilms on Implant Surfaces-An In Vitro Study with a Validated Multispecies Biofilm Model.}, journal = {International journal of molecular sciences}, volume = {25}, number = {6}, pages = {}, doi = {10.3390/ijms25063277}, pmid = {38542256}, issn = {1422-0067}, abstract = {This study aimed to evaluate the impact of Candida albicans on subgingival biofilm formation on dental implant surfaces. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to compare biofilm structure and microbial biomass in the presence and absence of the fungus after periods of 24, 48, and 72 h. Quantitative polymerase chain reaction (qPCR) was used to quantify the number of viable and total micro-organisms for each of the biofilm-forming strains. A general linear model was applied to compare CLSM and qPCR results between the control and test conditions. The biofilm developed with C. albicans at 72 h had a higher bacterial biomass and a significantly higher cell viability (p < 0.05). After both 48 and 72 h of incubation, in the presence of C. albicans, there was a significant increase in counts of Fusobacterium nucleatum and Porphyromonas gingivalis and in the cell viability of Streptococcus oralis, Aggregatibacter actinomycetemcomitans, F. nucleatum, and P. gingivalis. Using a dynamic in vitro multispecies biofilm model, C. albicans exacerbated the development of the biofilm grown on dental implant surfaces, significantly increasing the number and cell viability of periodontal bacteria.}, } @article {pmid38541692, year = {2024}, author = {Fehlhofer, J and Ries, J and Nickel, FT and Rothhammer, V and Schwab, S and Kesting, M and Buchbender, M}, title = {Expression of Inflammatory Mediators in Biofilm Samples and Clinical Association in Multiple Sclerosis Patients in Remission-A Pilot Study.}, journal = {Life (Basel, Switzerland)}, volume = {14}, number = {3}, pages = {}, doi = {10.3390/life14030367}, pmid = {38541692}, issn = {2075-1729}, abstract = {Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of unknown etiology that affects the central nervous system and can lead to neurological impairment. Our aim was to determine whether MS patients also show inflammatory changes in the oral cavity more frequently than healthy individuals. For this purpose, we examined plaque samples for various mediators and their correlation with clinical findings. A study group (MS) and a control group were examined and compared. The plaque samples were analyzed for the expression of interleukins (IL-2, -6, -10), matrix metalloproteinases (MMP-7, MMP-9), and a surface antigen CD90 by quantitative real-time PCR. The clinical parameters examined were the Mombelli plaque index; bleeding on probing (BOP) index; periodontal pocket depth; and decayed, missing, and filled tooth (DMFT) index. The expression of MMP9 was significantly (p = 0.035) higher in the control group. The expression of IL-2 was increased four-fold in the MS group; however, this difference was not statistically significant. The mean PD (p < 0.001) and BOP index (p = 0.029) values were increased in the study group. The clinical parameters of the BOP index and PD were significantly amplified in the MS patients. However, no causal relationship between the investigated inflammatory mediators and the clinical findings could be established in this case series.}, } @article {pmid38541385, year = {2024}, author = {Frąckiewicz, W and Pruss, A and Królikowski, M and Szymlet, P and Sobolewska, E}, title = {Comparison of the Intensity of Biofilm Production by Oral Microflora and Its Adhesion on the Surface of Zirconia Produced in Additive and Subtractive Technology: An In Vitro Study.}, journal = {Materials (Basel, Switzerland)}, volume = {17}, number = {6}, pages = {}, doi = {10.3390/ma17061231}, pmid = {38541385}, issn = {1996-1944}, abstract = {BACKGROUND: This in vitro study set out to find out how well oral cavity-dwelling bacteria can form biofilms and adhere on the surfaces of zirconium oxide samples created by 3D printing and milling technologies.

METHODS: 5 strains of microorganisms were used for the study, and 40 zirconium oxide samples were prepared, which were divided into two groups (n = 20)-20 samples produced using removal technology comprised the control group, while 20 samples produced by 3D printing technology comprised the test group. The prepared samples were placed in culture media of bacteria and fungi that naturally occur in the oral cavity. Then, the intensity of biofilm build-up on the samples was determined using qualitative and quantitative methods. The results for both materials were compared with each other.

RESULTS: No variations in the degree of biofilm deposition on zirconium oxide samples were found for the microorganisms Streptococcus mutans, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus. For Candida albicans fungi, more intense biofilm deposition was observed on samples made using 3D printing technology, but these differences were not statistically significant.

CONCLUSION: The biofilm accumulation intensity of ceramics produced by additive technology is comparable to that of milled zirconium oxide, which supports the material's broader use in clinical practice from a microbiological perspective. This ceramic has demonstrated its ability to compete with zirconium oxide produced by milling techniques in in vitro experiments, but sadly, no in vivo tests have yet been found to determine how this material will function in a patient's oral cavity.}, } @article {pmid38540741, year = {2024}, author = {Demjanenko, P and Zheng, S and Crane, JK}, title = {SOS-Inducing Drugs Trigger Nucleic Acid Release and Biofilm Formation in Gram-Negative Bacteria.}, journal = {Biomolecules}, volume = {14}, number = {3}, pages = {}, doi = {10.3390/biom14030321}, pmid = {38540741}, issn = {2218-273X}, support = {77548-20-1138250//Department of Internal Medicine, University at Buffalo/ ; }, abstract = {Our laboratory recently reported that induction of the SOS response, triggered by SOS-inducing drugs, was accompanied by a large release of DNA from enteric bacteria. The SOS response release had not previously been reported to include release of extracellular DNA from bacterial cells. We followed up on those observations in this current study and found that not just double-stranded DNA was being released, but also single-stranded DNA, RNA, and protein. SOS-inducing drugs also triggered formation of biofilm at the air-fluid interface on glass, and the biofilms contained DNA. We extended our study to test whether inhibitors of the SOS response would block DNA release and found that SOS inhibitors, including zinc salts, nitric oxide donors, and dequalinium, inhibited SOS-induced DNA release. The understanding that SOS-induced DNA release is associated with formation of biofilms increases our appreciation of the role of the SOS response in pathogenesis, as well as in emergence of new antibiotic resistance. Our findings with SOS inhibitors also suggest that regimens might be devised that could block the deleterious effects of the SOS response, at least temporarily, when this is desired.}, } @article {pmid38539154, year = {2024}, author = {Ahmed, NA and Othman, AS}, title = {Green fabrication of ZnO nanoparticles via spirulina platensis and its efficiency against biofilm forming pathogens.}, journal = {Microbial cell factories}, volume = {23}, number = {1}, pages = {92}, pmid = {38539154}, issn = {1475-2859}, abstract = {Excessive consumption of antibiotics is considered one of the top public health threats, this necessitates the development of new compounds that can hamper the spread of infections. A facile green technology for the biosynthesis of Zinc oxide nanoparticles (ZnO NPs) using the methanol extract of Spirulina platensis as a reducing and stabilizing agent has been developed. A bunch of spectroscopic and microscopic investigations confirmed the biogenic generation of nano-scaled ZnO with a mean size of 19.103 ± 5.66 nm. The prepared ZnO NPs were scrutinized for their antibacterial and antibiofilm potentiality, the inhibition zone diameters ranged from 12.57 ± 0.006 mm to 17.33 ± 0.006 mm (at 20 µg/mL) for a variety of Gram-positive and Gram-negative pathogens, also significant eradication of the biofilms formed by Staphylococcus aureus and Klebsiella pneumoniae by 96.7% and 94.8% respectively was detected. The free radical scavenging test showed a promising antioxidant capacity of the biogenic ZnO NPs (IC50=78.35 µg/mL). Furthermore, the anti-inflammatory role detected using the HRBCs-MSM technique revealed an efficient stabilization of red blood cells in a concentration-dependent manner. In addition, the biogenic ZnO NPs have significant anticoagulant and antitumor activities as well as minimal cytotoxicity against Vero cells. Thus, this study offered green ZnO NPs that can act as a secure substitute for synthetic antimicrobials and could be applied in numerous biomedical applications.}, } @article {pmid38538312, year = {2024}, author = {Oba, K and Suenaga, T and Yasuda, S and Kuroiwa, M and Hori, T and Lackner, S and Terada, A}, title = {Quest for Nitrous Oxide-reducing Bacteria Present in an Anammox Biofilm Fed with Nitrous Oxide.}, journal = {Microbes and environments}, volume = {39}, number = {1}, pages = {}, doi = {10.1264/jsme2.ME23106}, pmid = {38538312}, issn = {1347-4405}, abstract = {N2O-reducing bacteria have been examined and harnessed to develop technologies that reduce the emission of N2O, a greenhouse gas produced by biological nitrogen removal. Recent investigations using omics and physiological activity approaches have revealed the ecophysiologies of these bacteria during nitrogen removal. Nevertheless, their involvement in‍ ‍anammox processes remain unclear. Therefore, the present study investigated the identity, genetic potential, and activity‍ ‍of N2O reducers in an anammox reactor. We hypothesized that N2O is limiting for N2O-reducing bacteria‍ ‍and an‍ ‍exogeneous N2O supply enriches as-yet-uncultured N2O-reducing bacteria. We conducted a 1200-day incubation of N2O-reducing bacteria in an anammox consortium using gas-permeable membrane biofilm reactors (MBfRs), which efficiently supply N2O in a bubbleless form directly to a biofilm grown on a gas-permeable membrane. A [15]N tracer test indicated that the supply of N2O resulted in an enriched biomass with a higher N2O sink potential. Quantitative PCR and 16S rRNA amplicon sequencing revealed Clade II nosZ type-carrying N2O-reducing bacteria as protagonists of N2O sinks. Shotgun metagenomics showed the genetic potentials of the predominant Clade II nosZ-carrying bacteria, Anaerolineae and Ignavibacteria in MBfRs. Gemmatimonadota and non-anammox Planctomycetota increased their abundance in MBfRs despite their overall lower abundance. The implication of N2O as an inhibitory compound scavenging vitamin B12, which is essential for the synthesis of methionine, suggested its limited suppressive effect on the growth of B12-dependent bacteria, including N2O reducers. We identified Dehalococcoidia and Clostridia as predominant N2O sinks in an anammox consortium fed exogenous N2O because of the higher metabolic potential of vitamin B12-dependent biosynthesis.}, } @article {pmid38538267, year = {2024}, author = {Choi, LR and Harrison, Z and Montgomery, EC and Bush, JR and Abuhussein, E and Bumgardner, JD and Fujiwara, T and Jennings, JA}, title = {Chitosan Membranes Stabilized with Varying Acyl Lengths Release Cis-2-Decenoic Acid and Bupivacaine at Controlled Rates and Inhibit Pathogenic Biofilm.}, journal = {Frontiers in bioscience (Landmark edition)}, volume = {29}, number = {3}, pages = {108}, doi = {10.31083/j.fbl2903108}, pmid = {38538267}, issn = {2768-6698}, support = {W81XWH-20-1-0430//Military Burn Research Program (MBRP)/ ; //University of Memphis/University of Tennessee Health Science Center Joint Program in Biomedical Engineering/ ; }, abstract = {BACKGROUND: Adherence of complex bacterial biofilm communities to burned tissue creates a challenge for treatment, with infection causing 51% of burn victim deaths. This study evaluated the release of therapeutics from wound care biomaterials and their antimicrobial activity against pathogens Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa.

METHODS: Electrospun chitosan membranes (ESCMs) were fabricated and acylated with chain lengths ranging from 6-10 carbons then loaded with 0.15 mg of anti-biofilm agent, cis-2-decenoic acid (C2DA), and 0.5 mg of local anesthetic, bupivacaine.

RESULTS: Combinations of therapeutics released from modified ESCMs at a cumulative amount of 45-70% of bupivacaine and less than 20% of C2DA. Results from bacterial studies suggest that this combination reduced biofilm 10-fold for S. aureus, 2-fold for Acinetobacter baumannii, and 2-3-fold for Pseudomonas aeruginosa by 24 hours. Additionally, dual loaded groups reduced planktonic Staphylococcus aureus ~4-fold by 24 hours as well as Acinetobacter baumannii ~3-fold by 48 hours.

CONCLUSIONS: The combination of therapeutics used has a significant role in biofilm prevention for selected strains via direct contact or diffusion in aqueous solutions.}, } @article {pmid38537762, year = {2024}, author = {Xiao, J and Su, L and Chen, X and Huang, S and Zhou, M and Chen, Z}, title = {Molecular characteristics and biofilm formation capacity of nontypeable Haemophilus influenza strains isolated from lower respiratory tract in children.}, journal = {Microbial pathogenesis}, volume = {190}, number = {}, pages = {106632}, doi = {10.1016/j.micpath.2024.106632}, pmid = {38537762}, issn = {1096-1208}, abstract = {With the widespread introduction of the Hib conjugate vaccine, Nontypeable Haemophilus influenzae (NTHi) has emerged as the predominant strain globally. NTHi presents a significant challenge as a causative agent of chronic clinical infections due to its high rates of drug resistance and biofilm formation. While current research on NTHi biofilms in children has primarily focused on upper respiratory diseases, investigations into lower respiratory sources remain limited. In this study, we collected 54 clinical strains of lower respiratory tract origin from children. Molecular information and drug resistance features were obtained through whole gene sequencing and the disk diffusion method, respectively. Additionally, an in vitro biofilm model was established. All clinical strains were identified as NTHi and demonstrated the ability to form biofilms in vitro. Based on scanning electron microscopy and crystal violet staining, the strains were categorized into weak and strong biofilm-forming groups. We explored the correlation between biofilm formation ability and drug resistance patterns, as well as clinical characteristics. Stronger biofilm formation was associated with a longer cough duration and a higher proportion of abnormal lung imaging findings. Frequent intake of β-lactam antibiotics might be associated with strong biofilm formation. While a complementary relationship between biofilm-forming capacity and drug resistance may exist, further comprehensive studies are warranted. This study confirms the in vitro biofilm formation of clinical NTHi strains and establishes correlations with clinical characteristics, offering valuable insights for combating NTHi infections.}, } @article {pmid38537561, year = {2024}, author = {Li, C and Teng, F and Wu, F and Zhang, H and Zhang, C and Zhang, D}, title = {Enhanced cavitation dose and reactive oxygen species production in microbubble-mediated sonodynamic therapy for inhibition of Escherichia coli and biofilm.}, journal = {Ultrasonics sonochemistry}, volume = {105}, number = {}, pages = {106853}, doi = {10.1016/j.ultsonch.2024.106853}, pmid = {38537561}, issn = {1873-2828}, abstract = {Sonodynamic therapy (SDT) is an emerging antibacterial therapy. This work selected hematoporphyrin monomethyl ether (HMME) as the sonosensitizer, and studied the enhanced inhibition effect of Escherichia coli and biofilm by microbubble-mediated cavitation in SDT. Firstly, the influence of microbubble-mediated cavitation effect on different concentrations of HMME (10 µg/ml, 30 µg/ml, 50 µg/ml) was studied. Using 1,3-diphenylisobenzofuran (DPBF) as an indicator, the effect of microbubble-mediated cavitation on the production of reactive oxygen species (ROS) was studied by absorption spectroscopy. Secondly, using agar medium, laser confocal microscopy and scanning electron microscopy, the effect of microbubble-mediated cavitation on the activity and morphology of bacteria was studied. Finally, the inhibitory effect of cavitation combined with SDT on biofilm was evaluated by laser confocal microscopy. The research results indicate that: (1) Microbubble-mediated ultrasound cavitation can significantly increase cavitation intensity and production of ROS. (2) Microbubble-mediated acoustic cavitation can alter the morphological structure of bacteria. (3) It can significantly enhance the inhibition of SDT on the activity of Escherichia coli and its biofilm. Compared with the control group, the addition of microbubbles resulted in an increase in the number of dead bacteria by 61.7 %, 71.6 %, and 76.2 %, respectively. The fluorescence intensity of the biofilm decreased by 27.1 %, 80.3 %, and 98.2 %, respectively. On the basis of adding microbubbles to ensure antibacterial and biofilm inhibition effects, this work studied the influence of cavitation effect in SDT on bacterial structure, providing a foundation for further revealing the intrinsic mechanism of SDT.}, } @article {pmid38537031, year = {2024}, author = {Gomes, ACG and Maciel, JG and Garcia, AAMN and Coelho, LAS and Rodrigues, GM and Porto, VC and Polyzois, G and Klein, MI and Soares, S and Urban, VM and Neppelenbroek, KH}, title = {Anti-biofilm effectiveness of protocols for cleaning complete dentures in hospitalized patients: a randomized controlled trial.}, journal = {Journal of applied oral science : revista FOB}, volume = {32}, number = {}, pages = {e20230381}, doi = {10.1590/1678-7757-2022-0381}, pmid = {38537031}, issn = {1678-7765}, abstract = {BACKGROUND: Denture biofilm acts as a potential reservoir for respiratory pathogens, considerably increasing the risk of lung infections, specifically aspiration pneumonia, mainly 48h after hospital admission. The establishment of a straightforward, affordable, and applicable hygiene protocol in a hospital environment for the effective control of denture biofilm can be particularly useful to prevent respiratory infections or reduce the course of established lung disease.

OBJECTIVES: To evaluate the anti-biofilm effectiveness of denture cleaning protocols in hospitalized patients.

METHODOLOGY: The maxillary complete dentures (MCDs) of 340 hospitalized participants were randomly cleaned once using one of the following 17 protocols (n=20): brushing with distilled water, toothpaste, or neutral liquid soap (controls); immersion in chemical solutions (1% sodium hypochlorite, alkaline peroxide, 0.12% or 2% chlorhexidine digluconate), or microwave irradiation (650 W for 3 min) combined or not with brushing. Before and after the application of the protocols, the biofilm of the intaglio surface of the MCDs was evaluated using two methods: denture biofilm coverage area (%) and microbiological quantitative cultures on blood agar and Sabouraud Dextrose Agar (CFU/mL). Data were subjected to the Wilcoxon and Kruskal-Wallis tests (α=0.05).

RESULTS: All 17 protocols significantly reduced the percentage area of denture biofilm and microbial and fungal load (P<0.05). The highest percentage reductions in the area of denture biofilm were observed for 1% hypochlorite solution with or without brushing and for 2% chlorhexidine solution and microwave irradiation only in association with brushing (P<0.05). The greatest reductions in microbial and fungal load were found for the groups that used solutions of 2% chlorhexidine and 1% hypochlorite and microwave irradiation, regardless of the association with brushing (P<0.05).

CONCLUSIONS: A single immersion for 10 min in 1% sodium hypochlorite, even in the absence of brushing, proved to be a straightforward, rapid, low-cost, and effective protocol for cleaning the dentures of hospitalized patients.}, } @article {pmid38536433, year = {2024}, author = {Nag, M and Bhattacharya, D and Garai, S and Dutta, B and Ghosh, S and Ray, RR and Lahiri, D}, title = {Immobilised antimicrobial peptides in downregulation of biofilm.}, journal = {Naunyn-Schmiedeberg's archives of pharmacology}, volume = {}, number = {}, pages = {}, pmid = {38536433}, issn = {1432-1912}, abstract = {Colonisation of sessile bacterial species on biotic and abiotic surfaces is responsible for the development of various infections in humans. At present, biofilm-associated chronic infections have been a prime concern among the healthcare practitioners since they are impermeable to drugs, resulting in the development of antibiotic resistance or multi-drug resistance. For a few decades, a lot of research activity has been performed in the development of alternative therapeutics to combat biofilm-associated chronic infections. The presence of extracellular polymeric substance (EPS) prevents the permeation of most of the drugs rendering drug failures. The use of small molecules has been necessary to penetrate easily through the EPS and act on the targeted cells. In present days, the use of antimicrobial peptides (AMPs) has gained immense importance as alternative therapeutics since they exhibit a novel class of antibiotics exhibiting a wide spectrum of activity and possess a low rate of development of resistance. In the last few decades, a large number of AMPs have been identified from varied groups of organisms as effector molecules for innate immune system acting as an important line of defence. In this review, we will discuss the use of AMPs as effective agents to combat various biofilm-associated chronic infections.}, } @article {pmid38535596, year = {2024}, author = {Senyagin, A and Sachivkina, N and Das, M and Arsenyuk, A and Mannapova, R and Mannapov, A and Kubatbekov, T and Svistunov, D and Petrukhina, O and Zharov, A and Zhabo, N}, title = {The Influence of L-Lysine-Alpha-Oxidase on the Biofilm Formation of Opportunistic Microorganisms Associated with Inflammatory Diseases of the Urinary Tract.}, journal = {Pathogens (Basel, Switzerland)}, volume = {13}, number = {3}, pages = {}, doi = {10.3390/pathogens13030252}, pmid = {38535596}, issn = {2076-0817}, abstract = {Urinary tract infections occupy a special niche among diseases of infectious etiology. Many microorganisms associated with urinary tract infections, such as Klebsiella oxytoca, Enterococcus spp., Morganella morganii, Moraxella catarrhalis, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Staphylococcus spp., and Candida spp., can form biofilms. The aim of this research was to study the effect of the enzyme L-lysine-Alpha-oxidase (LO) produced by the fungus Trichoderma harzianum Rifai on the biofilm formation process of microorganisms associated with urinary tract infections. Homogeneous LO showed a more pronounced effect than the culture liquid concentrate (cCL). When adding samples at the beginning of incubation, the maximum inhibition was observed in relation to Enterococcus faecalis 5960-cCL 86%, LO 95%; Enterococcus avium 1669-cCL 85%, LO 94%; Enterococcus cloacae 6392-cCL 83%, LO-98%; and Pseudomonas aeruginosa 3057-cCL 70%, LO-82%. The minimum inhibition was found in Candida spp. Scanning electron microscopy was carried out, and numerous morphological and structural changes were observed in the cells after culturing the bacterial cultures in a medium supplemented with homogeneous LO. For example, abnormal division was detected, manifesting as the appearance of joints in places where the bacteria diverge. Based on the results of this work, we can draw conclusions about the possibility of inhibiting microbial biofilm formation with the use of LO; especially significant inhibition was achieved when the enzyme was added at the beginning of incubation. Thus, LO can be a promising drug candidate for the treatment or prevention of infections associated with biofilm formation.}, } @article {pmid38535555, year = {2024}, author = {González-Vázquez, R and Córdova-Espinoza, MG and Escamilla-Gutiérrez, A and Herrera-Cuevas, MDR and González-Vázquez, R and Esquivel-Campos, AL and López-Pelcastre, L and Torres-Cubillas, W and Mayorga-Reyes, L and Mendoza-Pérez, F and Gutiérrez-Nava, MA and Giono-Cerezo, S}, title = {Detection of mecA Genes in Hospital-Acquired MRSA and SOSA Strains Associated with Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {13}, number = {3}, pages = {}, doi = {10.3390/pathogens13030212}, pmid = {38535555}, issn = {2076-0817}, support = {SIP 20160618//Instituto Politécnico Nacional/ ; }, abstract = {Methicillin-resistant (MR) Staphylococcus aureus (SA) and others, except for Staphylococcus aureus (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm formation is encoded by the icaADBC operon and is involved in virulence. mecA encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of β-lactams at the target, found in the staphylococcal cassette chromosome mec (SCCmec). This work aims to detect mecA, the bap gene, the icaADBC operon, and types of SCCmec associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were S. aureus, 44% (35/80) S. epidermidis, 5% (4/80) S. haemolyticus, 2.5% (2/80) S. hominis, 1.25% (1/80) S. intermedius, and 1.25% (1/80) S. saprophyticus. A total of 85% were MR, of which 95.5% showed mecA and 86.7% β-lactamase producers; thus, Staphylococcus may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCCmec; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA mecA strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than Staphylococcus aureus). The operon icaADBC was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the mecA gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the icaADBC operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.}, } @article {pmid38535474, year = {2024}, author = {Carbone, D and Pecoraro, C and Scianò, F and Catania, V and Schillaci, D and Manachini, B and Cascioferro, S and Diana, P and Parrino, B}, title = {Novel [1,3,4]Thiadiazole[3,2-a]pyrimidin-5-ones as Promising Biofilm Dispersal Agents against Relevant Gram-Positive and Gram-Negative Pathogens.}, journal = {Marine drugs}, volume = {22}, number = {3}, pages = {}, doi = {10.3390/md22030133}, pmid = {38535474}, issn = {1660-3397}, support = {ARS01_00934//European Union 2014-2020 PON Ricerca e Innovazione grant from the Italian Ministry of Education/ ; }, abstract = {Biofilm-associated infections pose significant challenges in healthcare settings due to their resistance to conventional antimicrobial therapies. In the last decade, the marine environment has been a precious source of bioactive molecules, including numerous derivatives with antibiofilm activity. In this study, we reported the synthesis and the biological evaluation of a new series of twenty-two thiadiazopyrimidinone derivatives obtained by using a hybridization approach combining relevant chemical features of two important classes of marine compounds: nortopsentin analogues and Essramycin derivatives. The synthesized compounds were in vitro tested for their ability to inhibit biofilm formation and to disrupt mature biofilm in various bacterial strains. Among the tested compounds, derivative 8j exhibited remarkable dispersal activity against preformed biofilms of relevant Gram-positive and Gram-negative pathogens, as well as towards the fungus Candida albicans, showing BIC50 values ranging from 17 to 40 µg/mL. Furthermore, compound 8j was in vivo assayed for its toxicity and the anti-infective effect in a Galleria mellonella model. The results revealed a promising combination of anti-infective properties and a favorable toxicity profile for the treatment of severe chronic biofilm-mediated infections.}, } @article {pmid38534698, year = {2024}, author = {Akir, A and Senhaji-Kacha, A and Muñoz-Egea, MC and Esteban, J and Aguilera-Correa, JJ}, title = {Biofilm Development by Mycobacterium avium Complex Clinical Isolates: Effect of Clarithromycin in Ultrastructure.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {3}, pages = {}, doi = {10.3390/antibiotics13030263}, pmid = {38534698}, issn = {2079-6382}, abstract = {BACKGROUND: The Mycobacterium avium complex includes the commonest non-tuberculous mycobacteria associated with human infections. These infections have been associated with the production of biofilms in many cases, but there are only a few studies about biofilms produced by the species included in this group.

METHODS: Three collection strains (M. avium ATCC25291, M. intracellulare ATCC13950, and M. chimaera DSM756), three clinically significant strains (647, 657, and 655), and three clinically non-significant ones (717, 505, and 575) of each species were included. The clinical significance of the clinical isolates was established according to the internationally accepted criteria. The biofilm ultrastructure was studied by Confocal-Laser Scanning Microscopy by using BacLight Live-Dead and Nile Red stains. The viability, covered surface, height, and relative autofluorescence were measured in several images/strain. The effect of clarithromycin was studied by using the technique described by Muñoz-Egea et al. with modifications regarding incubation time. The study included clarithromycin in the culture medium at a concentration achievable in the lungs (11.3 mg/L), using one row of wells as the control without antibiotics. The bacterial viability inside the biofilm is expressed as a percentage of viable cells. The differences between the different parameters of the biofilm ultrastructure were analyzed by using the Kruskal-Wallis test. The correlation between bacterial viability in the biofilm and treatment time was evaluated by using Spearman's rank correlation coefficient (ρ).

RESULTS: The strains showed differences between them with all the studied parameters, but neither a species-specific pattern nor a clinical-significance-specific pattern were detected. For the effect of clarithromycin, the viability of the bacteria contained in the biofilm was inversely proportional to the exposure time of the biofilm (ρ > -0.3; p-value < 0.05), excluding two M. chimaera strains (M. chimaera DSM756 and 575), which showed a weak positive correlation with treatment time (0.2 < ρ < 0.39; p-value < 0.05). Curiously, despite a clarithromycin treatment of 216 h, the percentage of the biofilm viability of the strains evaluated here was not less than 40% at best (M. avium 717).

CONCLUSIONS: All the M. avium complex strains studied can form biofilm in vitro, but the ultrastructural characteristics between them suggest that these are strain-specific characteristics unrelated to the species or the clinical significance. The clarithromycin effect on MAC species is biofilm-age/time-of-treatment-dependent and appears to be strain-specific while being independent of the clinical significance of the strain.}, } @article {pmid38534200, year = {2024}, author = {Lopes, A-A and Vendrell-Fernández, S and Deschamps, J and Georgeault, S and Cokelaer, T and Briandet, R and Ghigo, J-M}, title = {Bile-induced biofilm formation in Bacteroides thetaiotaomicron requires magnesium efflux by an RND pump.}, journal = {mBio}, volume = {}, number = {}, pages = {e0348823}, doi = {10.1128/mbio.03488-23}, pmid = {38534200}, issn = {2150-7511}, abstract = {Bacteroides thetaiotaomicron is a prominent member of the human gut microbiota contributing to nutrient exchange, gut function, and maturation of the host's immune system. This obligate anaerobe symbiont can adopt a biofilm lifestyle, and it was recently shown that B. thetaiotaomicron biofilm formation is promoted by the presence of bile. This process also requires a B. thetaiotaomicron extracellular DNase, which is not, however, regulated by bile. Here, we showed that bile induces the expression of several Resistance-Nodulation-Division (RND) efflux pumps and that inhibiting their activity with a global competitive efflux inhibitor impaired bile-dependent biofilm formation. We then showed that, among the bile-induced RND-efflux pumps, only the tripartite BT3337-BT3338-BT3339 pump, re-named BipABC [for Bile Induced Pump A (BT3337), B (BT3338), and C (BT3339)], is required for biofilm formation. We demonstrated that BipABC is involved in the efflux of magnesium to the biofilm extracellular matrix, which leads to a decrease of extracellular DNA concentration. The release of magnesium in the biofilm matrix also impacts biofilm structure, potentially by modifying the electrostatic repulsion forces within the matrix, reducing interbacterial distance and allowing bacteria to interact more closely and form denser biofilms. Our study therefore, identified a new molecular determinant of B. thetaiotaomicron biofilm formation in response to bile salts and provides a better understanding on how an intestinal chemical cue regulates biofilm formation in a major gut symbiont.IMPORTANCEBacteroides thetaiotaomicron is a prominent member of the human gut microbiota able to degrade dietary and host polysaccharides, altogether contributing to nutrient exchange, gut function, and maturation of the host's immune system. This obligate anaerobe symbiont can adopt a biofilm community lifestyle, providing protection against environmental factors that might, in turn, protect the host from dysbiosis and dysbiosis-related diseases. It was recently shown that B. thetaiotaomicron exposure to intestinal bile promotes biofilm formation. Here, we reveal that a specific B. thetaiotaomicron membrane efflux pump is induced in response to bile, leading to the release of magnesium ions, potentially reducing electrostatic repulsion forces between components of the biofilm matrix. This leads to a reduction of interbacterial distance and strengthens the biofilm structure. Our study, therefore, provides a better understanding of how bile promotes biofilm formation in a major gut symbiont, potentially promoting microbiota resilience to stress and dysbiosis events.}, } @article {pmid38534119, year = {2024}, author = {Gu, Y and Liu, Y and Mao, W and Peng, Y and Han, X and Jin, H and Xu, J and Chang, L and Hou, Y and Shen, X and Liu, X and Yang, Y}, title = {Functional versatility of Zur in metal homeostasis, motility, biofilm formation, and stress resistance in Yersinia pseudotuberculosis.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0375623}, doi = {10.1128/spectrum.03756-23}, pmid = {38534119}, issn = {2165-0497}, abstract = {UNLABELLED: Zur (zinc uptake regulator) is a significant member of the Fur (ferric uptake regulator) superfamily, which is widely distributed in bacteria. Zur plays crucial roles in zinc homeostasis and influences cell development and environmental adaptation in various species. Yersinia pseudotuberculosis is a Gram-negative enteric that pathogen usually serves as a model organism in pathogenicity studies. The regulatory effects of Zur on the zinc transporter ZnuABC and the protein secretion system T6SS have been documented in Y. pseudotuberculosis. In this study, a comparative transcriptomics analysis between a ∆zur mutant and the wild-type (WT) strain of Y. pseudotuberculosis was conducted using RNA-seq. This analysis revealed global regulation by Zur across multiple functional categories, including membrane transport, cell motility, and molecular and energy metabolism. Additionally, Zur mediates the homeostasis not only of zinc but also ferric and magnesium in vivo. There was a notable decrease in 35 flagellar biosynthesis and assembly-related genes, leading to reduced swimming motility in the ∆zur mutant strain. Furthermore, Zur upregulated multiple simple sugar and oligopeptide transport system genes by directly binding to their promoters. The absence of Zur inhibited biofilm formation as well as reduced resistance to chloramphenicol and acidic stress. This study illustrates the comprehensive regulatory functions of Zur, emphasizing its importance in stress resistance and pathogenicity in Y. pseudotuberculosis.

IMPORTANCE: Bacteria encounter diverse stresses in the environment and possess essential regulators to modulate the expression of genes in responding to the stresses for better fitness and survival. Zur (zinc uptake regulator) plays a vital role in zinc homeostasis. Studies of Zur from multiple species reviewed that it influences cell development, stress resistance, and virulence of bacteria. Y. pseudotuberculosis is an enteric pathogen that serves a model organism in the study of pathogenicity, virulence factors, and mechanism of environmental adaptation. In this study, transcriptomics analysis of Zur's regulons was conducted in Y. pseudotuberculosis. The functions of Zur as a global regulator in metal homeostasis, motility, nutrient acquisition, glycan metabolism, and nucleotide metabolism, in turn, increasing the biofilm formation, stress resistance, and virulence were reviewed. The importance of Zur in environmental adaptation and pathogenicity of Y. pseudotuberculosis was emphasized.}, } @article {pmid38533074, year = {2024}, author = {Wang, J and Hu, Y and Xie, Y}, title = {Hotspots and frontiers in Helicobacter pylori biofilm research: A bibliometric and visualization analysis from 1998 to 2023.}, journal = {Heliyon}, volume = {10}, number = {6}, pages = {e27884}, pmid = {38533074}, issn = {2405-8440}, abstract = {BACKGROUND: Helicobacterpylori (H. pylori) biofilm formation is a key factor in refractory H. pylori infection. The aim of this study was to understand research trends in H. pylori biofilms.

METHODS: The Web of Science Core Collection database was used to retrieve publications published from 1998 to 2023. Different kinds of software, EXCEL, an online bibliometric analysis platform, and the VOS viewer were used to evaluate and visualize the bibliometric data.

RESULTS: In total, 184 publications were identified, and the number of publications increased annually. The USA made the greatest contributions to this research field, while Helicobacter was the most productive journal. Grande rossella published the most papers, and the most productive institution was Gabriele D'Annunzio university. Co-occurrence network maps revealed that the keyword "Helicobacter pylori" ranked first in research field, and the keyword of "biofilm formation" and "in vitro" began to appear in the past three to five years. The majority of the five most-cited articles (60%) were published in USA and focused on the mechanism of H. pylori biofilm formation.

CONCLUSION: The annual number of publications on H. pylori biofilms has increased steadily over the past two decades and will continue to increase. Future studies should focus on evaluate the pharmacological effects, efficacy and safety of these anti-biofilm treatments in animal models and clinical trials.}, } @article {pmid38532403, year = {2024}, author = {Dishan, A and Barel, M and Hizlisoy, S and Arslan, RS and Hizlisoy, H and Gundog, DA and Al, S and Gonulalan, Z}, title = {The ARIMA model approach for the biofilm-forming capacity prediction of Listeria monocytogenes recovered from carcasses.}, journal = {BMC veterinary research}, volume = {20}, number = {1}, pages = {123}, pmid = {38532403}, issn = {1746-6148}, abstract = {The present study aimed to predict the biofilm-formation ability of L. monocytogenes isolates obtained from cattle carcasses via the ARIMA model at different temperature parameters. The identification of L. monocytogenes obtained from carcass samples collected from slaughterhouses was determined by PCR. The biofilm-forming abilities of isolates were phenotypically determined by calculating the OD value and categorizing the ability via the microplate test. The presence of some virulence genes related to biofilm was revealed by QPCR to support the biofilm profile genotypically. Biofilm-formation of the isolates was evaluated at different temperature parameters (37 °C, 22 °C, 4 °C and - 20 °C). Estimated OD values were obtained with the ARIMA model by dividing them into eight different estimation groups. The prediction performance was determined by performance measurement metrics (ME, MAE, MSE, RMSE, MPE and MAPE). One week of incubation showed all isolates strongly formed biofilm at all controlled temperatures except - 20 °C. In terms of the metrics examined, the 3 days to 7 days forecast group has a reasonable prediction accuracy based on OD values occurring at 37 °C, 22 °C, and 4 °C. It was concluded that measurements at 22 °C had lower prediction accuracy compared to predictions from other temperatures. Overall, the best OD prediction accuracy belonged to the data obtained from biofilm formation at -20 °C. For all temperatures studied, especially after the 3 days to 7 days forecast group, there was a significant decrease in the error metrics and the forecast accuracy increased. When evaluating the best prediction group, the lowest RMSE at 37 °C (0.055), 22 °C (0.027) and 4 °C (0.024) belonged to the 15 days to 21 days group. For the OD predictions obtained at -20 °C, the 15 days to 21 days prediction group had also good performance (0.011) and the lowest RMSE belongs to the 7 days to 15 days group (0.007). In conclusion, this study will guide in using indicator parameters to evaluate biofilm forming ability to predict optimum temperature-time. The ARIMA models integrated with this study can be useful tools for industrial application and risk assessment studies using different parameters such as pH, NaCl concentration, and especially temperature applied during food processing and storage on the biofilm-formation ability of L. monocytogenes.}, } @article {pmid38530134, year = {2024}, author = {Araújo, GDS and Brilhante, RSN and Rocha, MGD and Aguiar, L and Castelo-Branco, DSCM and Guedes, GMM and Sidrim, JJC and Pereira Neto, WA and Rocha, MFG}, title = {Anthraquinones against Cryptococcus neoformans sensu stricto: antifungal interaction, biofilm inhibition and pathogenicity in the Caenorhabditis elegans model.}, journal = {Journal of medical microbiology}, volume = {73}, number = {3}, pages = {}, doi = {10.1099/jmm.0.001815}, pmid = {38530134}, issn = {1473-5644}, mesh = {Animals ; *Cryptococcus neoformans ; Antifungal Agents/pharmacology ; Caenorhabditis elegans ; Itraconazole ; Virulence ; *Cryptococcosis ; Anthraquinones/pharmacology ; Biofilms ; *Anthracenes ; }, abstract = {Introduction. Cryptococcal biofilms have been associated with persistent infections and antifungal resistance. Therefore, strategies, such as the association of natural compounds and antifungal drugs, have been applied for the prevention of biofilm growth. Moreover, the Caenorhabditis elegans pathogenicity model has been used to investigate the capacity to inhibit the pathogenicity of Cryptococcus neoformans sensu stricto.Hypothesis. Anthraquinones and antifungals are associated with preventing C. neoformans sensu stricto biofilm formation and disrupting these communities. Antraquinones reduced the C. neoformans sensu stricto pathogenicity in the C. elegans model.Aim. This study aimed to evaluate the in vitro interaction between aloe emodin, barbaloin or chrysophanol and itraconazole or amphotericin B against growing and mature biofilms of C. neoformans sensu stricto.Methodology. Compounds and antifungal drugs were added during biofilm formation or after 72 h of growth. Then, the metabolic activity was evaluated by the MTT reduction assay, the biomass by crystal-violet staining and the biofilm morphology by confocal laser scanning microscopy. C. neoformans sensu stricto's pathogenicity was investigated using the nematode C. elegans. Finally, pathogenicity inhibition by aloe emodin, barbarloin and chrysophanol was investigated using this model.Results. Anthraquinone-antifungal combinations affected the development of biofilms with a reduction of over 60 % in metabolic activity and above 50 % in biomass. Aloe emodin and barbaloin increased the anti-biofilm activity of antifungal drugs. Chrysophanol potentiated the effect of itraconazole against C. neoformans sensu stricto biofilms. The C. elegans mortality rate reached 76.7 % after the worms were exposed to C. neoformans sensu stricto for 96 h. Aloe emodin, barbaloin and chrysophanol reduced the C. elegans pathogenicity with mortality rates of 61.12 %, 65 % and 53.34 %, respectively, after the worms were exposed for 96 h to C. neoformans sensu stricto and these compounds at same time.Conclusion. These results highlight the potential activity of anthraquinones to increase the effectiveness of antifungal drugs against cryptococcal biofilms.}, } @article {pmid38529559, year = {2024}, author = {Hadjab, W and Zellagui, A and Mokrani, M and Öztürk, M and Ceylan, Ö and Gherraf, N and Bensouici, C}, title = {Pharmacological Potential Effects of Algerian Propolis Against Oxidative Stress, Multidrug-Resistant Pathogens Biofilm and Quorum-Sensing.}, journal = {Turkish journal of pharmaceutical sciences}, volume = {21}, number = {1}, pages = {71-80}, doi = {10.4274/tjps.galenos.2023.64369}, pmid = {38529559}, issn = {2148-6247}, abstract = {OBJECTIVES: This study sought to examine the chemical profile, antioxidant, antimicrobial, antibiofilm, and anti-quorum sensing potential of two propolis ethanolic extracts (PEEs) collected from northeast Algeria.

MATERIALS AND METHODS: To achieve the main objectives of this study, multiple in vitro tests were employed. The phenolic and flavonoid contents were analyzed, and the chemical composition of both PEE was determined by high-performance liquid chromatography. The antioxidant properties of the propolis extracts were investigated using six complementary tests. The inhibitory effects of propolis extracts were evaluated against multidrug-resistant (MDR) clinical isolates using agar well diffusion and microdilution methods, whereas their antibiofilm and quorum-sensing disruption effects were determined by spectrophotometric microplate methods.

RESULTS: The results demonstrated that phenolic and flavonoid contents were higher in propolis from the Guelma (PEEG) region (PEEG; 188.50 ± 0.33 μg GAE/mg E, 144.23 ± 1.03 μg QE/mg E), respectively. Interestingly, different components were identified, and cynarin was the major compound detected. The PEEG sample exhibited potential antioxidant effects in scavenging ABTS[•+] radicals with minimal inhibitory concentration values equal to 10.46 ± 1.40 µg/mL. Furthermore, the highest antibacterial activity was recorded by PEEG against Gram-positive Staphylococcus aureus MDR1. Similarly, PEEG effectively inhibited the biofilm formation of S. aureus MDR1 and the degradation of biofilm was up to 60%. In addition, quorum sensing disruption revealed that both extracts have a moderate capacity for violacein inhibition by the Chromobacterium violaceum ATCC 12472 strain in a concentration-dependent manner.

CONCLUSION: These findings indicate that propolis can be regarded as a natural therapeutic agent for health problems associated with MDR bacteria and oxidative stress.}, } @article {pmid38528442, year = {2024}, author = {Hemmati, J and Nazari, M and Abolhasani, FS and Ahmadi, A and Asghari, B}, title = {In vitro investigation of relationship between quorum-sensing system genes, biofilm forming ability, and drug resistance in clinical isolates of Pseudomonas aeruginosa.}, journal = {BMC microbiology}, volume = {24}, number = {1}, pages = {99}, pmid = {38528442}, issn = {1471-2180}, mesh = {Humans ; Quorum Sensing/genetics ; Pseudomonas aeruginosa ; Biofilms ; *Pseudomonas Infections/microbiology ; Drug Resistance, Microbial ; *Cross Infection ; Bacterial Proteins/metabolism ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen in the health-care systems and one of the primary causative agents with high mortality in hospitalized patients, particularly immunocompromised. The limitation of effective antibiotic administration in multidrug-resistant and extensively drug-resistant P. aeruginosa isolates leads to the development of nosocomial infections and health problems. Quorum sensing system contributes to biofilm formation, expression of bacterial virulence factors, and development of drug resistance, causing prolonged patient infections. Therefore, due to the significance of the quorum sensing system in increasing the pathogenicity of P. aeruginosa, the primary objective of our study was to investigate the frequency of quorum sensing genes, as well as the biofilm formation and antibiotic resistance pattern among P. aeruginosa strains.

METHODS: A total of 120 P. aeruginosa isolates were collected from different clinical specimens. The disk diffusion method was applied to detect the antibiotic resistance pattern of P. aeruginosa strains. Also, the microtiter plate method was carried out to evaluate the biofilm-forming ability of isolates. Finally, the frequency of rhlI, rhlR, lasI, and lasR genes was examined by the polymerase chain reaction method.

RESULTS: In total, 88.3% P. aeruginosa isolates were found to be multidrug-resistant, of which 30.1% had extensively drug-resistant pattern. The highest and lowest resistance rates were found against ceftazidime (75.0%) and ciprofloxacin (46.6%), respectively. Also, 95.8% of isolates were able to produce biofilm, of which 42.5%, 33.3%, and 20.0% had strong, moderate, and weak biofilm patterns, respectively. The frequency of quorum sensing genes among all examined strains was as follows: rhlI (81.6%), rhlR (90.8%), lasI (89.1%), and lasR (78.3%). The most common type of quorum sensing genes among multidrug-resistant isolates were related to rhlR and lasI genes with 94.3%. Furthermore, rhlI, rhlR, and lasI genes were positive for all extensively drug-resistant isolates. However, the lasR gene had the lowest frequency among both multidrug-resistant (83.0%) and extensively drug-resistant (90.6%) isolates. Moreover, rhlR (94.7%) and lasR (81.7%) genes had the highest and lowest prevalence among biofilm-forming isolates, respectively.

CONCLUSION: Our findings disclosed the significantly high prevalence of drug resistance among P. aeruginosa isolates. Also, the quorum sensing system had a significant correlation with biofilm formation and drug resistance, indicating the essential role of this system in the emergence of nosocomial infections caused by P. aeruginosa.}, } @article {pmid38527879, year = {2024}, author = {Jiang, X and Wang, M and Yang, S and He, D and Fang, F and Yang, L}, title = {The response of structure and nitrogen removal function of the biofilm on submerged macrophytes to high ammonium in constructed wetlands.}, journal = {Journal of environmental sciences (China)}, volume = {142}, number = {}, pages = {129-141}, doi = {10.1016/j.jes.2023.07.004}, pmid = {38527879}, issn = {1001-0742}, abstract = {The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands (CWs). The effects of high ammonium shocks on submerged macrophytes and epiphytic biofilms on the leaves of submerged macrophytes in CWs were rarely mentioned in previous studies. In this paper, the 16S rRNA sequencing method was used to investigate the variation of the microbial communities in biofilms on the leaves of Vallisneria natans plants while the growth characteristics of V. natans plants were measured at different initial ammonium concentrations. The results demonstrated that the total chlorophyll and soluble sugar synthesis of V. natans plants decreased by 51.45% and 57.16%, respectively, and malondialdehyde content increased threefold after 8 days if the initial NH4[+]-N concentration was more than 5 mg/L. Algal density, bacterial quantity, dissolved oxygen, and pH increased with high ammonium shocks. The average removal efficiencies of total nitrogen and NH4[+]-N reached 73.26% and 83.94%, respectively. The heat map and relative abundance analysis represented that the relative abundances of phyla Proteobacteria, Cyanobacteria, and Bacteroidetes increased. The numbers of autotrophic nitrifiers and heterotrophic nitrification aerobic denitrification (HNAD) bacteria expanded in biofilms. In particular, HNAD bacteria of Flavobacterium, Hydrogenophaga, Acidovorax, Acinetobacter, Pseudomonas, Aeromonas, and Azospira had higher abundances than autotrophic nitrifiers because there were organic matters secreted from declining leaves of V. natans plants. The analysis of the nitrogen metabolic pathway showed aerobic denitrification was the main nitrogen removal pathway. Thus, the nitrification and denitrification bacterial communities increased in epiphytic biofilms on submerged macrophytes in constructed wetlands while submerged macrophytes declined under ammonium shock loading.}, } @article {pmid38527516, year = {2024}, author = {Purwasena, IA and Fitri, DK and Putri, DM and Endro, H and Zakaria, MN}, title = {Lipopeptide Biosurfactant as a Potential Root Canal Irrigation Agent: Antimicrobial and Anti-Biofilm Evaluation.}, journal = {Journal of dentistry}, volume = {}, number = {}, pages = {104961}, doi = {10.1016/j.jdent.2024.104961}, pmid = {38527516}, issn = {1879-176X}, abstract = {OBJECTIVES: Lipopeptide Biosurfactant (LB) is bacteria derived compound able to reduce surface tension between water and hydrophobic substances and exhibit antimicrobial and anti-biofilm properties. This study aimed to investigate the antimicrobial and anti-biofilm effect of a Lipopeptide Biosurfactant (LB) on Enterococcus faecalis, and its potential use in root canal treatment, either as a standalone irrigation solution or in conjunction with sodium hypochlorite (NaOCl).

METHODS: LB was extracted from Bacillus clausii isolate and the dry extract was diluted in deionized water. The antimicrobial effect of LB against planktonic E. faecalis was evaluated by determining the Minimal Inhibitory Concentration (MIC50). The anti-biofilm effect was evaluated by Minimal Biofilm Inhibitory Concentration (MBIC50) and Minimal Biofilm Eradication Concentration (MBEC50) assays on biofilm grown on dentin specimen surface. To evaluate the effectiveness of LB as a single irrigation solution and as a pre-irrigation prior to NaOCl, live and dead bacterial cells were quantified using Confocal Laser Scanning Microscopy (CLSM), and cell biomass was assessed.

RESULTS: LB exhibited an MIC50 and MBIC50 of 100 ppm, with an MBEC50 of 1000 ppm, resulting in 52.94% biofilm inhibition and 60.95% biofilm eradication on dentin specimens. The effectiveness was concentration-dependent, at 500 ppm, LB demonstrated comparable antimicrobial efficacy to 2.5% NaOCl. Pre-irrigation with LB resulted in lower biofilm biomass compared to NaOCl alone.

CONCLUSION: Pre-irrigation with LB enhanced the antimicrobial effect when followed by NaOCl irrigation. Consequently, LB shows promise as both a standalone root canal irrigation solution and as an adjunct to NaOCl in root canal treatment.

CLINICAL SIGNIFICANCE: The study highlights the potential of Lipopeptide Biosurfactant (LB) as an environmentally friendly irrigation solution for root canal treatment, demonstrating potent antimicrobial and anti-biofilm properties against Enterococcus faecalis. LB exhibits concentration-dependent efficacy comparable to 2.5% NaOCl and can be used as a standalone irrigation solution or in conjunction with NaOCl.}, } @article {pmid38526664, year = {2024}, author = {Roy, R and Paul, P and Chakraborty, P and Malik, M and Das, S and Chatterjee, S and Maity, A and Dasgupta, M and Sarker, RK and Sarkar, S and Das Gupta, A and Tribedi, P}, title = {Cuminaldehyde and Tobramycin Forestall the Biofilm Threats of Staphylococcus aureus: A Combinatorial Strategy to Evade the Biofilm Challenges.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {38526664}, issn = {1559-0291}, support = {R&D/2020/F2//The Neotia University/ ; }, abstract = {Staphylococcus aureus, an opportunistic Gram-positive pathogen, is known for causing various infections in humans, primarily by forming biofilms. The biofilm-induced antibiotic resistance has been considered a significant medical threat. Combinatorial therapy has been considered a reliable approach to combat antibiotic resistance by using multiple antimicrobial agents simultaneously, targeting bacteria through different mechanisms of action. To this end, we examined the effects of two molecules, cuminaldehyde (a natural compound) and tobramycin (an antibiotic), individually and in combination, against staphylococcal biofilm. Our experimental observations demonstrated that cuminaldehyde (20 μg/mL) in combination with tobramycin (0.05 μg/mL) exhibited efficient reduction in biofilm formation compared to their individual treatments (p < 0.01). Additionally, the combination showed an additive interaction (fractional inhibitory concentration value 0.66) against S. aureus. Further analysis revealed that the effective combination accelerated the buildup of reactive oxygen species (ROS) and increased the membrane permeability of the bacteria. Our findings also specified that the cuminaldehyde in combination with tobramycin efficiently reduced biofilm-associated pathogenicity factors of S. aureus, including fibrinogen clumping ability, hemolysis property, and staphyloxanthin production. The selected concentrations of tobramycin and cuminaldehyde demonstrated promising activity against the biofilm development of S. aureus on catheter models without exerting antimicrobial effects. In conclusion, the combination of tobramycin and cuminaldehyde presented a successful strategy for combating staphylococcal biofilm-related healthcare threats. This combinatorial approach holds the potential for controlling biofilm-associated infections caused by S. aureus.}, } @article {pmid38526390, year = {2024}, author = {Huang, D and Liu, J and Yang, J and Liang, J and Zhang, J and Han, Q and Yu, J and Yang, T and Meng, Q and Steinberg, T and Chang, Z and Li, C}, title = {Restoration of pregnancy function using GT/PCL biofilm in a rabbit model of uterine injury.}, journal = {Tissue engineering. Part A}, volume = {}, number = {}, pages = {}, doi = {10.1089/ten.TEA.2023.0366}, pmid = {38526390}, issn = {1937-335X}, abstract = {Biomaterial scaffolds have been used successfully to promote the regenerative repair of small endometrial lesions in small rodents, providing partial restoration of gestational function. The use of rabbits in this study allowed us to investigate a larger endometrial tissue defect and myometrial-injury model. A gelatin/polycaprolactone (GT/PCL) gradient-layer biofilm was sutured at the defect to guide the reconstruction of the original tissue structure. 28 days post-implantation, the uterine cavity had been restored its original morphology; endometrial growth was accompanied by the formation of glands and blood vessels, and the fragmented myofibers of the uterine smooth muscle had begun to resemble the normal structure of the lagomorph uterine cavity, arranging in a circular luminal pattern and a longitudinal serosal pattern. In addition, the repair site supported both embryonic implantation into the placenta and normal embryonic development. 4D label-free proteomic analysis identified the cell adhesion molecules (CAMs), phagosome, ferroptosis, rap1 signaling pathways, hematopoietic cell lineage, complement and coagulation cascades, tricarboxylic acid (TCA) cycle, carbon metabolism, and HIF-1 signaling pathways as important in the endogenous repair process of uterine-tissue injury, and acetylation of protein modification sites upregulated these signaling pathways.}, } @article {pmid38525143, year = {2024}, author = {Roselló, J and Llorens-Molina, JA and Larran, S and Sempere-Ferre, F and Santamarina, MP}, title = {Biofilm containing the Thymus serpyllum essential oil for rice and cherry tomato conservation.}, journal = {Frontiers in plant science}, volume = {15}, number = {}, pages = {1362569}, pmid = {38525143}, issn = {1664-462X}, abstract = {INTRODUCTION: Fungal pathogens cause major yield losses in agriculture and reduce food quality and production worldwide.

PURPOSE: To evaluate new safer alternatives to chemicals for disease management and preserve the shelf life of food, this research was conducted to: determine the chemical composition of the essential oils (EOs) of Thymus serpyllum and Thymus piperella chemotypes 1 and 2; investigate the antifungal potential of EOs in vitro against: Alternaria alternata, Bipolaris spicifera, Curvularia hawaiiensis, Fusarium oxysporum f. sp. lycopersici, Penicillium italicum, Botryotinia fuckeliana; evaluate a natural T. serpyllum extract biofilm to conserve rice grain and cherry tomatoes.

METHOD: EOs were analyzed by GC-MS+GC-FID. EOs' antifungal activity was evaluated by dissolving Thymus extracts in PDA. Petri dishes were inoculated with disks of each fungus and incubated at 25°C for 7 days.

RESULTS: The T. serpyllum EO displayed the best Mycelial Growth Inhibition. The antifungal effect of the T. serpyllum EO biofilm was evaluated on rice caryopsis. Disinfected grains were dipped in a conidial suspension of each fungus and sprayed with EO (300 and 600 μg/mL) prepared in Tween 20. Grains were stored. The percentage of infected grains was recorded for 30 days. The T. serpyllum EO effect on cherry tomato conservation was evaluated in vivo. Wounded fruit were immersed in the T. serpyllum EO (300 and 400 μg/mL) and inoculated with Fusarium oxysporum f. sp. lycopersici. Fruit were evaluated for 7 and 14 days. Chemical profiles thymol/carvacrol for T. serpyllum, carvacrol for T. piperella Tp1 and thymol for T. piperella Tp2 were defined. The three evaluated EOs reduced all the studied phytopathogens' fungal growth. The T. serpyllum biofilm was effective with rice storage and against Fusarium oxysporum f. sp. lycopersici for extending the shelf life of tomatoes in warehouses and storing postharvest cherry tomatoes.

CONCLUSION: We suggest applying these EOs as biofilms for safe food conservation to replace synthetic products.}, } @article {pmid38525010, year = {2024}, author = {Ling, Y and Duan, M and Lyu, W and Yang, J and Liu, Y and Ren, S and Wu, W}, title = {Electrospun L-Lysine/Amorphous Calcium Phosphate Loaded Core-Sheath Nanofibers for Managing Oral Biofilm Infections and Promoting Periodontal Tissue Repairment.}, journal = {International journal of nanomedicine}, volume = {19}, number = {}, pages = {2917-2938}, pmid = {38525010}, issn = {1178-2013}, abstract = {INTRODUCTION: Periodontitis, a chronic inflammatory disease prevalent worldwide, is primarily treated through GTR for tissue regeneration. The efficacy of GTR, however, remains uncertain due to potential infections and the intricate microenvironment of periodontal tissue. Herein, We developed a novel core-shell structure multifunctional membrane using a dual-drug-loaded coaxial electrospinning technique (Lys/ACP-CNF), contains L-lysine in the outer layer to aid in controlling biofilms after GTR regenerative surgery, and ACP in the inner layer to enhance osteogenic performance for accelerating alveolar bone repair.

METHODS: The biocompatibility and cell adhesion were evaluated through CCK-8 and fluorescence imaging, respectively. The antibacterial activity was assessed using a plate counting assay. ALP, ARS, and RT-qPCR were used to examine osteogenic differentiation. Additionally, an in vivo experiment was conducted on a rat model with acute periodontal defect and infection. Micro-CT and histological analysis were utilized to analyze the in vivo alveolar bone regeneration.

RESULTS: Structural and physicochemical characterization confirmed the successful construction of the core-shell fibrous structure. Additionally, the Lys/ACP-CNF showed strong antibacterial coaggregation effects and induced osteogenic differentiation of PDLSCs in vitro. The in vivo experiment confirmed that Lys/ACP-CNF promotes new bone formation.

CONCLUSION: Lys/ACP-CNF rapidly exhibited excellent antibacterial activity, protected PDLSCs from infection, and was conducive to osteogenesis, demonstrating its potential application for clinical periodontal GTR surgery.}, } @article {pmid38522670, year = {2024}, author = {Wang, X and Wang, T and Meng, H and Xing, F and Yun, H}, title = {Anammox process in anaerobic baffled biofilm reactors with columnar packings: Characteristics of flow field and microbial community.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141774}, doi = {10.1016/j.chemosphere.2024.141774}, pmid = {38522670}, issn = {1879-1298}, abstract = {The enrichment of anammox bacteria is a key issue in the application of anammox processes. A new type of reactor － anaerobic baffle biofilm reactor (ABBR) developed from anaerobic baffle reactor (ABR) was filled with columnar packings and established for effective enrichment of anammox bacteria. The flow field analysis showed that, compared with ABR, ABBR narrowed the dead zone so as to improve the substrate transferring performances. Two ABBRs with different types of columnar packings (Packings 1 and Packings 2) were constructed to culture anammox biofilms. Packings 1 consisted of the single-form honeycomb carriers while Packings 2 was modular composite packings consisting of non-woven fabric and honeycomb carriers. The effects of different types of columnar packings on microbial community and nitrogen removal were studied. The ABBR filled with Packings 2 had a higher retention rate of biomass than the ABBR filled with Packings 1, making the anammox start-up period be shortened by 21.28%. The enrichment of anammox bacteria were achieved and the dominant anammox bacteria were Candidatus Brocadia in both R1 and R2. However, there were four genera of anammox bacteria in R2 and one genus of anammox bacteria in R1, and the cell density of anammox bacteria in R2 was 95% higher than that in R1. R2 has the advantage of maintaining excellent and stable nitrogen removal performance at high nitrogen loading rate. The results revealed that the packings composed of two types of carriers may have a better enrichment effect on anammox bacteria. This study is of great significance for the rapid enrichment of anammox bacteria and the technical promotion of anammox process.}, } @article {pmid38522282, year = {2024}, author = {Li, H and Zeng, X and Yao, T and Xu, H}, title = {An antimicrobial film of silver/nanocellulose crystal/oxalic acid/polyvinyl alcohol with real-time bactericidal and prevention of biofilm formation properties.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {237}, number = {}, pages = {113868}, doi = {10.1016/j.colsurfb.2024.113868}, pmid = {38522282}, issn = {1873-4367}, abstract = {Silver nanoparticles (AgNPs) is an excellent antibacterial agent, which is widely used in medical, food, environmental and other fields, but AgNPs are easy to accumulate in aqueous solution, so their application in various fields is limited. Therefore, it is particularly important to propose a new application method or to prepare a new composite material. In this study, OA/PVA was obtained by cross-linking oxalic acid (OA) with polyvinyl alcohol (PVA). Then Ag/NCC was obtained by in situ reduction of AgNPs on nanocellulose crystals (NCC). Finally, Ag/NCC/OA/PVA composite antimicrobial films with good waterproofing effect were prepared by mixing Ag/NCC with OA/PVA. Subsequently, the films were characterized using SEM, UV-vis, FTIR and XRD, as well as physicochemical properties such as mechanical strength and hydrophilic properties were determined. The results indicated that the Ag/NCC/OA/PVA films possess good light transmittance, mechanical properties, water resistance, antibacterial activity, and biodegradability. The results of the mechanism study showed that Ag/NCC/OA/PVA films can destroy cell integrity, inhibit succinate dehydrogenase (SDH) activity, thereby reducing intracellular ATP levels. And induce a large number of reactive oxygen species (ROS) production, eventually leading to the death of C. sakazakii. In summary, Ag/NCC/OA/PVA film has good physical and chemical properties, antibacterial activity and biocompatibility, and has promising applications in food and medical antibacterial fields.}, } @article {pmid38521769, year = {2024}, author = {Yaeger, LN and Ranieri, MRM and Chee, J and Karabelas-Pittman, S and Rudolph, M and Giovannoni, AM and Harvey, H and Burrows, LL}, title = {A genetic screen identifies a role for oprF in Pseudomonas aeruginosa biofilm stimulation by subinhibitory antibiotics.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {30}, pmid = {38521769}, issn = {2055-5008}, support = {RGPIN-2021-04237//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; PGS-D//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; USRA//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; }, mesh = {Humans ; *Anti-Bacterial Agents/pharmacology/metabolism ; Pseudomonas aeruginosa/physiology ; Escherichia coli/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Pseudomonas Infections ; Phosphoric Diester Hydrolases ; Disulfides/metabolism ; }, abstract = {Biofilms are surface-associated communities of bacteria that grow in a self-produced matrix of polysaccharides, proteins, and extracellular DNA (eDNA). Sub-minimal inhibitory concentrations (sub-MIC) of antibiotics induce biofilm formation, potentially as a defensive response to antibiotic stress. However, the mechanisms behind sub-MIC antibiotic-induced biofilm formation are unclear. We show that treatment of Pseudomonas aeruginosa with multiple classes of sub-MIC antibiotics with distinct targets induces biofilm formation. Further, addition of exogenous eDNA or cell lysate failed to increase biofilm formation to the same extent as antibiotics, suggesting that the release of cellular contents by antibiotic-driven bacteriolysis is insufficient. Using a genetic screen for stimulation-deficient mutants, we identified the outer membrane porin OprF and the ECF sigma factor SigX as important. Similarly, loss of OmpA - the Escherichia coli OprF homolog - prevented sub-MIC antibiotic stimulation of E. coli biofilms. Our screen also identified the periplasmic disulfide bond-forming enzyme DsbA and a predicted cyclic-di-GMP phosphodiesterase encoded by PA2200 as essential for biofilm stimulation. The phosphodiesterase activity of PA2200 is likely controlled by a disulfide bond in its regulatory domain, and folding of OprF is influenced by disulfide bond formation, connecting the mutant phenotypes. Addition of reducing agent dithiothreitol prevented sub-MIC antibiotic biofilm stimulation. Finally, activation of a c-di-GMP-responsive promoter follows treatment with sub-MIC antibiotics in the wild-type but not an oprF mutant. Together, these results show that antibiotic-induced biofilm formation is likely driven by a signaling pathway that translates changes in periplasmic redox state into elevated biofilm formation through increases in c-di-GMP.}, } @article {pmid38521361, year = {2024}, author = {Tiraboschi, G and Isaac, P and Breser, ML and Angiolini, V and Rodriguez-Berdini, L and Porporatto, C and Bohl, LP}, title = {1,25 DIHYDROXYVITAMIN D3-MEDIATED EFFECTS ON BOVINE INNATE IMMUNITY AND ON BIOFILM-FORMING Staphylococcus spp. ISOLATED FROM CATTLE WITH MASTITIS.}, journal = {The Journal of steroid biochemistry and molecular biology}, volume = {}, number = {}, pages = {106508}, doi = {10.1016/j.jsbmb.2024.106508}, pmid = {38521361}, issn = {1879-1220}, abstract = {Mastitis is one the most widespread and serious diseases in dairy cattle. Recurrent and chronic infections are often attributable to certain pathogenicity mechanisms in mastitis-causing pathogens such as Staphylococcus spp. These include growing in biofilm and invading cells, both of which make it possible to resist or evade antimicrobial therapies and the host's immune system. This study tested the effects of active vitamin D3 (i.e., calcitriol or 1,25-dihydroxyvitamin D3) on the internalization and phagocytosis of biofilm-forming Staphylococcus spp. isolated from animals with mastitis. Two established bovine cell lines were used: MAC-T (mammary epithelial cells) and BoMac (macrophages). Calcitriol (0-200nM) did not affect the viability of MAC-T cells nor that of BoMac cells after 24 and 72h. Concentrations of 0-100mM for 24h upregulated the expression of 24-hydroxylase in MAC-T cells, but did not alter that of VDR. Pre-treatment of the cells with calcitriol for 24h decreased the internalization of S. aureus V329 into MAC-T cells (0-100nM), and stimulated the phagocytosis of the same strain and of S. xylosus 4913 (0-10nM). Calcitriol and two conditioned media, obtained by treating the cells with 25-200nM of the metabolite for 24h, were also assessed in terms of their antimicrobial and antibiofilm activity. Neither calcitriol by itself nor the conditioned media affected staphylococcal growth or biofilm formation (0-200nM for 12 and 24h, respectively). In contrast, the conditioned media (0-100nM for 24h) decreased the biomass of preformed non-aureus staphylococcal biofilms and killed the bacteria within them, without affecting metabolic activity. These effects may be mediated by reactive oxygen species and proteins with antimicrobial and/or antibiofilm activity. In short, calcitriol could make pathogens more accessible to antimicrobial therapies and enhance bacterial clearance by professional phagocytes. Moreover, it may modulate the host's endogenous defenses in the bovine udder and help combat preformed non-aureus staphylococcal biofilms (S. chromogenes 40, S. xylosus 4913, and/or S. haemolyticus 6). The findings confirm calcitriol's potential as an adjuvant to prevent and/or treat intramammary infections caused by Staphylococcus spp., which would in turn contribute to reducing antibiotic use on dairy farms.}, } @article {pmid38521108, year = {2024}, author = {Zhang, C and Zeng, X and Xu, X and Nie, W and Dubey, BK and Ding, W}, title = {PDA-Fe3O4 decorated carbon felt anode enhancing electrochemical performance of microbial fuel cells: Effect of electrode materials on electroactive biofilm.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141764}, doi = {10.1016/j.chemosphere.2024.141764}, pmid = {38521108}, issn = {1879-1298}, abstract = {Anode modification is an effective strategy for enhancing the electrochemical performance of microbial fuel cell (MFC). However, the impacts of the modified materials on anode biofilm development during MFC operation have been less studied. We prepared a novel PDA-Fe3O4-CF composite anode by coating original carbon felt anode (CF) with polydopamine (PDA) and Fe3O4 nanoparticles. The composite anode material was characterized by excellent hydrophilicity and electrical conductivity, and the anodic biofilm exhibited fast start-up, higher biomass, and more uniform biofilm layer after MFC operation. The MFC reactor assembled with the composite anode achieved a maximum power density of 608 mW m[-2] and an output voltage of 586 mV, which were 316.4% and 72.4% higher than the MFC with the original CF anode, respectively. Microbial community analysis indicated that the modified anode biofilm had a higher relative abundance of exoelectrogen species in comparison to the unmodified anode. The PICRUSt data revealed that the anodic materials may affect the bioelectrochemical performance of the biofilm by influencing the expression levels of key enzyme genes involved in biofilm extracellular polymer (EPS) secretion and extracellular electron transfer (EET). The growth of the anodic biofilm would exert positive or negative influences on the efficiency of electricity production and electron transfer of the MFCs at different operating stages. This work expands the knowledge of the role that anodic materials play in the development and electrochemical performance of anodic biofilm in MFCs.}, } @article {pmid38520779, year = {2024}, author = {Zhang, Z and Li, D and Zhou, C and Huang, X and Chen, Y and Wang, S and Liu, G}, title = {Enhanced nitrogen removal via partial nitrification/denitrification coupled Anammox using three stage anoxic/oxic biofilm process with intermittent aeration.}, journal = {Water research}, volume = {255}, number = {}, pages = {121491}, doi = {10.1016/j.watres.2024.121491}, pmid = {38520779}, issn = {1879-2448}, abstract = {Pre-capturing organics in municipal wastewater for biogas production, combined with Anammox-based nitrogen removal process, improves the sustainability of sewage treatment. Thus, enhancing nitrogen removal via Anammox in mainstream wastewater treatment becomes very crucial. In present study, a three-stage anoxic/oxic (AO) biofilm process with intermittent aeration was designed to strengthen partial nitrification/denitrification coupling Anammox (PNA/PDA) in treatment of low C/N wastewater, which contained chemical oxygen demand (COD) of 79.8 mg/L and total inorganic nitrogen (TIN) of 58.9 mg/L. With a hydraulic retention time of 8.0 h, the process successfully reduced TIN to 10.6 mg/L, achieving a nitrogen removal efficiency of 83.3 %. The 1[st] anoxic zone accounted for 32.0 % TIN removal, with 10.3 % by denitrification and 21.7 % by PDA, meanwhile, the 2[nd] and 3[rd] anoxic zones contributed 19.4 % and 4.5 % of TIN removal, primarily achieved through PDA (including endogenous PD coupling Anammox). The 1[st] and 2[nd] intermittent zones accounted for 27.2 % and 17.0 % of TIN removal, respectively, with 13.7 %-21.3 % by PNA and 3.2 %-5.3 % by PDA. Although this process did not pursue nitrite accumulation in any zone (< 1.5 mg-N/L), PNA and PDA accounted for 35.1 % and 52.1 % of TIN removal, respectively. Only 0.21 % of removed TIN was released as nitrous oxide. The AnAOB of Candidatus Brocadia was enriched in each zone, with a relative abundance of 0.66 %-2.29 %. In intermittent zones, NOB had been partially suppressed (AOB/NOB = 0.73-0.88), mainly due to intermittent aeration and effective nitrite utilization by AnAOB since its population size was much greater than NOB. Present study indicated that the three-stage AO biofilm process with intermittent aeration could enhance nitrogen removal via PNA and PDA with a low N2O emission factor.}, } @article {pmid38520490, year = {2024}, author = {Polyudova, T and Lemkina, L and Eroshenko, D and Esaev, A}, title = {Suppression of planktonic and biofilm of Escherichia coli by the synergistic lantibiotics-polymyxins combinations.}, journal = {Archives of microbiology}, volume = {206}, number = {4}, pages = {191}, pmid = {38520490}, issn = {1432-072X}, abstract = {Escherichia coli are generally resistant to the lantibiotic's action (nisin and warnerin), but we have shown increased sensitivity of E. coli to lantibiotics in the presence of subinhibitory concentrations of polymyxins. Synergistic lantibiotic-polymyxin combinations were found for polymyxins B and M. The killing of cells at the planktonic and biofilm levels was observed for two collection and four clinical multidrug-resistant E. coli strains after treatment with lantibiotic-polymyxin B combinations. Thus, 24-h treatment of E. coli mature biofilms with warnerin-polymyxin B or nisin-polymyxin B leads to five to tenfold decrease in the number of viable cells, depending on the strain. AFM revealed that the warnerin and polymyxin B combination caused the loss of the structural integrity of biofilm and the destruction of cells within the biofilm. It has been shown that pretreatment of cells with polymyxin B leads to an increase of Ca[2+] and Mg[2+] ions in the culture medium, as detected by atomic absorption spectroscopy. The subsequent exposure to warnerin caused cell death with the loss of K[+] ions and cell destruction with DNA and protein release. Thus, polymyxins display synergy with lantibiotics against planktonic and biofilm cells of E. coli, and can be used to overcome the resistance of Gram-negative bacteria to lantibiotics.}, } @article {pmid38520398, year = {2024}, author = {Kozuka, Y and Masuda, T and Isu, N and Takai, M}, title = {Antimicrobial Peptide Assembly on Zwitterionic Polymer Films to Slow Down Biofilm Formation.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.langmuir.4c00086}, pmid = {38520398}, issn = {1520-5827}, abstract = {Formation of biofilms on equipment used in various fields, such as medicine, domestic sanitation, and marine transportation, can cause serious problems. The use of antibiofouling and bactericidal modifications is a promising strategy for inhibiting bacterial adhesion and biofilm formation. To further enhance the antibiofilm properties of a surface, various combinations of bactericidal modifications alongside antibiofouling modifications have been developed. Optimization of the arrangements of antimicrobial peptides on the antibiofouling surface would allow us to design longer-life antibiofilm surface modifications. In this study, a postmodification was conducted with different design using the antimicrobial peptide KR12 on an antibiofouling copolymer film consisting of 2-methacryloyloxyethyl phosphorylcholine, 3-methacryloxypropyl trimethoxysilane, and 3-(methacryloyloxy) propyl-tris(trimethylsilyloxy) silane. The distance of KR12 from the film was adjusted by combining different lengths of poly(ethylene glycol) (PEG) spacers (molecular weights are 2000 and 5000). The density of KR12 was ranged from 0.06 to 0.22 nm[-2]. When these modified surfaces were exposed to a nutrient-rich TSB suspension, the bacterial area formed by E. coli covered 5-127% of the original copolymer film. We found that a significant distance between the bactericidal and antibiofouling modifications, along with a higher density of bactericidal modifications, slows down the biofilm formation.}, } @article {pmid38519959, year = {2024}, author = {Aboelnaga, N and Elsayed, SW and Abdelsalam, NA and Salem, S and Saif, NA and Elsayed, M and Ayman, S and Nasr, M and Elhadidy, M}, title = {Deciphering the dynamics of methicillin-resistant Staphylococcus aureus biofilm formation: from molecular signaling to nanotherapeutic advances.}, journal = {Cell communication and signaling : CCS}, volume = {22}, number = {1}, pages = {188}, pmid = {38519959}, issn = {1478-811X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) represents a global threat, necessitating the development of effective solutions to combat this emerging superbug. In response to selective pressures within healthcare, community, and livestock settings, MRSA has evolved increased biofilm formation as a multifaceted virulence and defensive mechanism, enabling the bacterium to thrive in harsh conditions. This review discusses the molecular mechanisms contributing to biofilm formation across its developmental stages, hence representing a step forward in developing promising strategies for impeding or eradicating biofilms. During staphylococcal biofilm development, cell wall-anchored proteins attach bacterial cells to biotic or abiotic surfaces; extracellular polymeric substances build scaffolds for biofilm formation; the cidABC operon controls cell lysis within the biofilm, and proteases facilitate dispersal. Beside the three main sequential stages of biofilm formation (attachment, maturation, and dispersal), this review unveils two unique developmental stages in the biofilm formation process for MRSA; multiplication and exodus. We also highlighted the quorum sensing as a cell-to-cell communication process, allowing distant bacterial cells to adapt to the conditions surrounding the bacterial biofilm. In S. aureus, the quorum sensing process is mediated by autoinducing peptides (AIPs) as signaling molecules, with the accessory gene regulator system playing a pivotal role in orchestrating the production of AIPs and various virulence factors. Several quorum inhibitors showed promising anti-virulence and antibiofilm effects that vary in type and function according to the targeted molecule. Disrupting the biofilm architecture and eradicating sessile bacterial cells are crucial steps to prevent colonization on other surfaces or organs. In this context, nanoparticles emerge as efficient carriers for delivering antimicrobial and antibiofilm agents throughout the biofilm architecture. Although metal-based nanoparticles have been previously used in combatting biofilms, its non-degradability and toxicity within the human body presents a real challenge. Therefore, organic nanoparticles in conjunction with quorum inhibitors have been proposed as a promising strategy against biofilms. As nanotherapeutics continue to gain recognition as an antibiofilm strategy, the development of more antibiofilm nanotherapeutics could offer a promising solution to combat biofilm-mediated resistance.}, } @article {pmid38519175, year = {2024}, author = {Fan, L and Dai, H and Zhou, W and Yuan, L and Yang, J and Yang, Z and Jiao, XA}, title = {Unraveling the significance of calcium as a biofilm promotion signal for Bacillus licheniformis strains isolated from dairy products.}, journal = {Food research international (Ottawa, Ont.)}, volume = {182}, number = {}, pages = {114145}, doi = {10.1016/j.foodres.2024.114145}, pmid = {38519175}, issn = {1873-7145}, abstract = {Bacillus licheniformis, a quick and strong biofilm former, is served as a persistent microbial contamination in the dairy industry. Its biofilm formation process is usually regulated by environmental factors including the divalent cation Ca[2+]. This work aims to investigate how different concentrations of Ca[2+] change biofilm-related phenotypes (bacterial motility, biofilm-forming capacity, biofilm structures, and EPS production) of dairy B. licheniformis strains. The Ca[2+] ions dependent regulation mechanism for B. licheniformis biofilm formation was further investigated by RNA-sequencing analysis. Results revealed that supplementation of Ca[2+] increased B. licheniformis biofilm formation in a dose-dependent way, and enhanced average coverage and thickness of biofilms with complex structures were observed by confocal laser scanning microscopy. Bacterial mobility of B. licheniformis was increased by the supplementation of Ca[2+] except the swarming ability at 20 mM of Ca[2+]. The addition of Ca[2+] decreased the contents of polysaccharides but promoted proteins production in EPS, and the ratio of proteins/polysaccharides content was significantly enhanced with increasing Ca[2+] concentrations. RNA-sequencing results clearly indicated the variation in regulating biofilm formation under different Ca[2+] concentrations, as 939 (671 upregulated and 268 downregulated) and 951 genes (581 upregulated and 370 downregulated) in B. licheniformis BL2-11 were induced by 10 and 20 mM of Ca[2+], respectively. Differential genes were annotated in various KEGG pathways, including flagellar assembly, two-component system, quorum sensing, ABC transporters, and related carbohydrate and amino acid metabolism pathways. Collectively, the results unravel the significance of Ca[2+] as a biofilm-promoting signal for B. licheniformis in the dairy industry.}, } @article {pmid38518879, year = {2024}, author = {Sheng, M and Ye, Z and Zhu, F and Pan, D and Shao, S and Wu, X}, title = {New insights into nitrogen removal by divalent iron-enhanced moving bed biofilm reactor: Performance, interfacial interaction and co-occurrence network.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130621}, doi = {10.1016/j.biortech.2024.130621}, pmid = {38518879}, issn = {1873-2976}, abstract = {A divalent iron-mediated moving bed biofilm reactor with intermittent aeration was developed to enhance the nitrogen removal at low carbon-to-nitrogen ratios. The study demonstrated thatammonia removal increased from 51 ± 4 % to 79 ± 4 % and nitrate removal increased from 72 ± 5 % to 98 ± 4 % in phases I-IV, and 2-5 mg·L[-1] of divalent iron significantly increased the anoxic denitrification process. Divalent iron stimulated the secretion of extracellular polymeric substances, which facilitated the formation of cross-linked network between microbial cells. Furthermore, the cycle between divalent and trivalent iron decreased the energy barrier between the biofilm and the pollutant. The microbial community further revealed that Proteobacteria (relative abundance: 40-48 %) andBacteroidota(relative abundance: 31-37 %) were the dominant phyla, supporting the synchronous nitrification and denitrification processes as well as the lower accumulation of nitrite. In conclusion, iron redox cycling significantly enhanced the nitrogen removal. This study proposes a viable strategy for the efficient treatment of nutrient wastewater.}, } @article {pmid38518822, year = {2024}, author = {Colas, S and Marie, B and Morin, S and Milhe-Poutingon, M and Foucault, P and Chalvin, S and Gelber, C and Baldoni-Andrey, P and Gurieff, N and Fortin, C and Le Faucheur, S}, title = {New sensitive tools to characterize meta-metabolome response to short- and long-term cobalt exposure in dynamic river biofilm communities.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {171851}, doi = {10.1016/j.scitotenv.2024.171851}, pmid = {38518822}, issn = {1879-1026}, abstract = {Untargeted metabolomics is a non-a priori analysis of biomolecules that characterizes the metabolome variations induced by short- and long-term exposures to stressors. Even if the metabolite annotation remains lacunar due to database gaps, the global metabolomic fingerprint allows for trend analyses of dose-response curves for hundreds of cellular metabolites. Analysis of dose/time-response curve trends (biphasic or monotonic) of untargeted metabolomic features would thus allow the use of all the chemical signals obtained in order to determine stress levels (defense or damage) in organisms. To develop this approach in a context of time-dependent microbial community changes, mature river biofilms were exposed for 1 month to four cobalt (Co) concentrations (from background concentration to 1 × 10[-6] M) in an open system of artificial streams. The meta-metabolomic response of biofilms was compared against a multitude of biological parameters (including bioaccumulation, biomass, chlorophyll a content, composition and structure of prokaryotic and eukaryotic communities) monitored at set exposure times (from 1 h to 28 days). Cobalt exposure induced extremely rapid responses of the meta-metabolome, with time range inducing defense responses (TRIDeR) of around 10 s, and time range inducing damage responses (TRIDaR) of several hours. Even in biofilms whose structure had been altered by Co bioaccumulation (reduced biomass, chlorophyll a contents and changes in the composition and diversity of prokaryotic and eukaryotic communities), concentration range inducing defense responses (CRIDeR) with similar initiation thresholds (1.41 ± 0.77 × 10[-10] M Co[2+] added in the exposure medium) were set up at the meta-metabolome level at every time point. In contrast, the concentration range inducing damage responses (CRIDaR) initiation thresholds increased by 10 times in long-term Co exposed biofilms. The present study demonstrates that defense and damage responses of biofilm meta-metabolome exposed to Co are rapidly and sustainably impacted, even within tolerant and resistant microbial communities.}, } @article {pmid38518773, year = {2024}, author = {Granton, E and Brown, L and Defaye, M and Moazen, P and Almblad, H and Randall, TE and Rich, JD and Geppert, A and Abdullah, NS and Hassanabad, MF and Hiroki, CH and Farias, R and Nguyen, AP and Schubert, C and Lou, Y and Andonegui, G and Iftinca, M and Raju, D and Vargas, MA and Howell, PL and Füzesi, T and Bains, J and Kurrasch, D and Harrison, JJ and Altier, C and Yipp, BG}, title = {Biofilm exopolysaccharides alter sensory-neuron-mediated sickness during lung infection.}, journal = {Cell}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cell.2024.03.001}, pmid = {38518773}, issn = {1097-4172}, abstract = {Infections of the lung cause observable sickness thought to be secondary to inflammation. Signs of sickness are crucial to alert others via behavioral-immune responses to limit contact with contagious individuals. Gram-negative bacteria produce exopolysaccharide (EPS) that provides microbial protection; however, the impact of EPS on sickness remains uncertain. Using genome-engineered Pseudomonas aeruginosa (P. aeruginosa) strains, we compared EPS-producers versus non-producers and a virulent Escherichia coli (E. coli) lung infection model in male and female mice. EPS-negative P. aeruginosa and virulent E. coli infection caused severe sickness, behavioral alterations, inflammation, and hypothermia mediated by TLR4 detection of the exposed lipopolysaccharide (LPS) in lung TRPV1[+] sensory neurons. However, inflammation did not account for sickness. Stimulation of lung nociceptors induced acute stress responses in the paraventricular hypothalamic nuclei by activating corticotropin-releasing hormone neurons responsible for sickness behavior and hypothermia. Thus, EPS-producing biofilm pathogens evade initiating a lung-brain sensory neuronal response that results in sickness.}, } @article {pmid38516014, year = {2024}, author = {Oliveira, LT and Marcos, CM and Cabral, AKLF and Medina-Alarcón, KP and Pires, RH and Fusco-Almeida, AM and Mendes-Giannini, MJS}, title = {Paracoccidioides spp.: the structural characterization of extracellular matrix, expression of glucan synthesis and associated genes and adhesins during biofilm formation.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1354140}, pmid = {38516014}, issn = {1664-302X}, abstract = {The genus Paracoccidioides includes Paracoccidioides lutzii and the Paracoccidioides brasiliensis complex, which comprises four phylogenetic species. A key feature distinguishing planktonic growth from biofilm is the presence of a 3D extracellular matrix (ECM). Therefore, in this study, we analyzed biofilm formation in different species of Paracoccidioides yeast phase, characterized the structural elements of the matrix of P. brasiliensis (Pb18), P. lutzii (Pl01 and 8334) and P. restrepiensis (339 and 192) and evaluated the expression of glucan genes, according to the stage of biofilm evolution for P. brasiliensis. The strains were cultivated in planktonic and biofilm form for 24-144 h. The fungi biomass and metabolic activity were determined by crystal violet and tetrazolium salt reduction (XTT) tests and colony-forming unit (CFU) by plating. The biofilm structure was designed using scanning electron microscopy and confocal laser scanning microscopy techniques. The extracellular matrix of P. brasiliensis and P. lutzii biofilms was extracted by sonication, and polysaccharides, proteins, and extracellular DNA (eDNA) were quantified. The RNA was extracted with the Trizol[®] reagent and quantified; then, the cDNA was synthesized to analyze the enolase expression, 14-3-3, FKS1, AGS1, GEL3, and KRE6 genes by real-time PCR. All strains of Paracoccidioides studied form a biofilm with more significant metabolic activity and biomass values in 144 h. The extracellular matrix of P. brasiliensis and P. lutzii had a higher content of polysaccharides in their composition, followed by proteins and eDNA in smaller quantities. The P. brasiliensis biofilm kinetics of formation showed greater expression of genes related to glucan's synthesis and its delivery to the external environment in addition adhesins during the biofilm's adhesion, initiation, and maturation. The GEL3 and enolase genes increased in expression within 24 h and during the biofilm maturation period, there was an increase in 14-3-3, AGS1, and FKS1. Furthermore, at 144 h, there was a decrease in KRE6 expression and an increase in GEL3. This study highlights the potential for biofilm formation for three species of Paracoccidioides and the main components of the extracellular matrix that can contribute to a better understanding of biofilm organization.}, } @article {pmid38516008, year = {2024}, author = {Nicholson, TL and Waack, U and Fleming, DS and Chen, Q and Miller, LC and Merkel, TJ and Stibitz, S}, title = {The contribution of BvgR, RisA, and RisS to global gene regulation, intracellular cyclic-di-GMP levels, motility, and biofilm formation in Bordetella bronchiseptica.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1305097}, pmid = {38516008}, issn = {1664-302X}, abstract = {Bordetella bronchiseptica is a highly contagious respiratory bacterial veterinary pathogen. In this study the contribution of the transcriptional regulators BvgR, RisA, RisS, and the phosphorylation of RisA to global gene regulation, intracellular cyclic-di-GMP levels, motility, and biofilm formation were evaluated. Next Generation Sequencing (RNASeq) was used to differentiate the global gene regulation of both virulence-activated and virulence-repressed genes by each of these factors. The BvgAS system, along with BvgR, RisA, and the phosphorylation of RisA served in cyclic-di-GMP degradation. BvgR and unphosphorylated RisA were found to temporally regulate motility. Additionally, BvgR, RisA, and RisS were found to be required for biofilm formation.}, } @article {pmid38515541, year = {2024}, author = {Catania, S and Bottinelli, M and Fincato, A and Tondo, A and Matucci, A and Nai, G and Righetti, V and Abbate, F and Ramírez, AS and Gobbo, F and Merenda, M}, title = {Pathogenic avian mycoplasmas show phenotypic differences in their biofilm forming ability compared to non-pathogenic species in vitro.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100190}, pmid = {38515541}, issn = {2590-2075}, abstract = {Mycoplasmas are known as the minimalist microorganisms in the microbes' world. Their minimalist nature makes them highly sensitive to the environmental conditions and limits their ability to survive for extended periods outside their animal host. Nevertheless, there are documented instances of mycoplasma transmission over significant distances and this phenomenon may be linked to relatively unexplored abilities of mycoplasmas, such as their capacity to synthesize biofilm-the predominant mode of bacterial growth in nature. The authors decided to establish a method aimed at inducing the clustering of mycoplasma planktonic cells within a biofilm in vitro and subsequently assess the capacity of certain avian mycoplasmas to synthesize a biofilm. A total of 299 avian mycoplasma isolates were included in the study, encompassing both pathogenic (Mycoplasma gallisepticum, M. synoviae, M. meleagridis, M. iowae) and non-pathogenic species (M. gallinaceum, M. gallinarum, M. iners and M. pullorum). The authors successfully demonstrated the feasibility of inducing avian mycoplasmas to synthetize in vitro a biofilm, which can be visually quantified. The only species that did not produce any biofilm was M. iowae. In general, the pathogenic mycoplasmas produced greater quantities of biofilm compared to the non-pathogenic ones. Furthermore, it was observed that the ability to produce biofilm appeared to vary, both qualitatively and quantitatively, not only among different species but also among isolates of a single species. Future studies will be necessary to determine whether biofilm production plays a pivotal epidemiological role for the pathogenic avian mycoplasmas.}, } @article {pmid38514634, year = {2024}, author = {Carreira de Paula, J and García Olmedo, P and Gómez-Moracho, T and Buendía-Abad, M and Higes, M and Martín-Hernández, R and Osuna, A and de Pablos, LM}, title = {Promastigote EPS secretion and haptomonad biofilm formation as evolutionary adaptations of trypanosomatid parasites for colonizing honeybee hosts.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {27}, pmid = {38514634}, issn = {2055-5008}, abstract = {Bees are major pollinators involved in the maintenance of all terrestrial ecosystems. Biotic and abiotic factors placing these insects at risk is a research priority for ecological and agricultural sustainability. Parasites are one of the key players of this global decline and the study of their mechanisms of action is essential to control honeybee colony losses. Trypanosomatid parasites and particularly the Lotmaria passim are widely spread in honeybees, however their lifestyle is poorly understood. In this work, we show how these parasites are able to differentiate into a new parasitic lifestyle: the trypanosomatid biofilms. Using different microscopic techniques, we demonstrated that the secretion of Extracellular Polymeric Substances by free-swimming unicellular promastigote forms is a prerequisite for the generation and adherence of multicellular biofilms to solid surfaces in vitro and in vivo. Moreover, compared to human-infective trypanosomatid parasites our study shows how trypanosomatid parasites of honeybees increases their resistance and thus resilience to drastic changes in environmental conditions such as ultralow temperatures and hypoosmotic shock, which would explain their success thriving within or outside their hosts. These results set up the basis for the understanding of the success of this group of parasites in nature and to unveil the impact of such pathogens in honeybees, a keystones species in most terrestrial ecosystems.}, } @article {pmid38512170, year = {2024}, author = {Pham, HN and Than, TDN and Nguyen, HA and Vu, DH and Phung, TH and Nguyen, TK}, title = {Antibiotic Resistance, Biofilm Formation, and Persistent Phenotype of Klebsiella pneumoniae in a Vietnamese Tertiary Hospital: A Focus on Amikacin.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {}, number = {}, pages = {}, doi = {10.1089/mdr.2023.0267}, pmid = {38512170}, issn = {1931-8448}, abstract = {Klebsiella pneumoniae stands out as a major opportunistic pathogen responsible for both hospital- and community-acquired bacterial infections. This study comprehensively assesses the antibiotic resistance, amikacin persistent patterns, and biofilm-forming ability of 247 isolates of K. pneumoniae obtained from an intensive care unit of a tertiary hospital in Vietnam. Microdilution assays, conducted on a 96-well plate, determined the minimum inhibitory concentrations (MICs) of amikacin. Susceptibility data for other antibiotics were gathered from the antibiogram profile. Stationary-phase bacteria were exposed to 50 × MIC, and viable bacteria counts were measured to determine amikacin persistence. Biofilm forming capacity on 96-well polystyrene surfaces was assessed by biomass and viable bacteria. The prevalence of resistance was notably high across most antibiotics, with 64.8% classified as carbapenem-resistant K. pneumoniae and 81.4% as multidrug resistant. Amikacin, however, exhibited a relatively low rate of resistance. Of the isolates, 58.2% demonstrated a moderate to strong biofilm formation capacity, and these were found to be poorly responsive to amikacin. K. pneumoniae reveals a significant inclination for amikacin persistence, with ∼45% of isolates displaying an antibiotic antibiotic-survival ratio exceeding 10%. The study sheds light on challenges in treating of K. pneumoniae infection in Vietnam, encompassing a high prevalence of antibiotic resistance, a substantial ability to form biofilm, and a notable rate of antibiotic persistence.}, } @article {pmid38511958, year = {2024}, author = {Gager, C and Flores-Mireles, AL}, title = {Blunted blades: new CRISPR-derived technologies to dissect microbial multi-drug resistance and biofilm formation.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0064223}, doi = {10.1128/msphere.00642-23}, pmid = {38511958}, issn = {2379-5042}, abstract = {The spread of multi-drug-resistant (MDR) pathogens has rapidly outpaced the development of effective treatments. Diverse resistance mechanisms further limit the effectiveness of our best treatments, including multi-drug regimens and last line-of-defense antimicrobials. Biofilm formation is a powerful component of microbial pathogenesis, providing a scaffold for efficient colonization and shielding against anti-microbials, which further complicates drug resistance studies. Early genetic knockout tools didn't allow the study of essential genes, but clustered regularly interspaced palindromic repeat inference (CRISPRi) technologies have overcome this challenge via genetic silencing. These tools rapidly evolved to meet new demands and exploit native CRISPR systems. Modern tools range from the creation of massive CRISPRi libraries to tunable modulation of gene expression with CRISPR activation (CRISPRa). This review discusses the rapid expansion of CRISPRi/a-based technologies, their use in investigating MDR and biofilm formation, and how this drives further development of a potent tool to comprehensively examine multi-drug resistance.}, } @article {pmid38511008, year = {2024}, author = {Goudot, S and Mathieu, L and Herbelin, P and Soreau, S and Jorand, FPA}, title = {Growth dynamic of biofilm-associated Naegleria fowleri in freshwater on various materials.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1369665}, pmid = {38511008}, issn = {1664-302X}, abstract = {In industrial water systems, the occurrence of biofilm-associated pathogenic free-living amoebae (FLA) such as Naegleria fowleri is a potential hygienic problem, and factors associated with its occurrence remain poorly understood. This study aimed to evaluate the impact of four cooling circuit materials on the growth of N. fowleri in a freshwater biofilm formed at 42°C and under a hydrodynamic shear rate of 17 s[-1] (laminar flow): polyvinyl chloride, stainless steel, brass, and titanium. Colonization of the freshwater biofilms by N. fowleri was found to be effective on polyvinyl chloride, stainless steel, and titanium. For these three materials, the ratio of (bacterial prey)/(amoeba) was found to control the growth of N. fowleri. All materials taken together, a maximum specific growth rate of 0.18 ± 0.07 h[-1] was associated with a generation time of ~4 h. In contrast, no significant colonization of N. fowleri was found on brass. Therefore, the contribution of copper is strongly suspected.}, } @article {pmid38510214, year = {2024}, author = {Kadirvelu, L and Sivaramalingam, SS and Jothivel, D and Chithiraiselvan, DD and Karaiyagowder Govindarajan, D and Kandaswamy, K}, title = {A review on antimicrobial strategies in mitigating biofilm-associated infections on medical implants.}, journal = {Current research in microbial sciences}, volume = {6}, number = {}, pages = {100231}, pmid = {38510214}, issn = {2666-5174}, abstract = {Biomedical implants are crucial in providing support and functionality to patients with missing or defective body parts. However, implants carry an inherent risk of bacterial infections that are biofilm-associated and lead to significant complications. These infections often result in implant failure, requiring replacement by surgical restoration. Given these complications, it is crucial to study the biofilm formation mechanism on various biomedical implants that will help prevent implant failures. Therefore, this comprehensive review explores various types of implants (e.g., dental implant, orthopedic implant, tracheal stent, breast implant, central venous catheter, cochlear implant, urinary catheter, intraocular lens, and heart valve) and medical devices (hemodialyzer and pacemaker) in use. In addition, the mechanism of biofilm formation on those implants, and their pathogenesis were discussed. Furthermore, this article critically reviews various approaches in combating implant-associated infections, with a special emphasis on novel non-antibiotic alternatives to mitigate biofilm infections.}, } @article {pmid38509138, year = {2024}, author = {Karačić, S and Palmer, B and Gee, CT and Bierbaum, G}, title = {Oxygen-dependent biofilm dynamics in leaf decay: an in vitro analysis.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {6728}, pmid = {38509138}, issn = {2045-2322}, support = {348043586//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Biofilms are important in the natural process of plant tissue degradation. However, fundamental knowledge of biofilm community structure and succession on decaying leaves under different oxygen conditions is limited. Here, we used 16S rRNA and ITS gene amplicon sequencing to investigate the composition, temporal dynamics, and community assembly processes of bacterial and fungal biofilms on decaying leaves in vitro. Leaves harvested from three plant species were immersed in lake water under aerobic and anaerobic conditions in vitro for three weeks. Biofilm-covered leaf samples were collected weekly and investigated by scanning electron microscopy. The results showed that community composition differed significantly between biofilm samples under aerobic and anaerobic conditions, though not among plant species. Over three weeks, a clear compositional shift of the bacterial and fungal biofilm communities was observed. The alpha diversity of prokaryotes increased over time in aerobic assays and decreased under anaerobic conditions. Oxygen availability and incubation time were found to be primary factors influencing the microbial diversity of biofilms on different decaying plant species in vitro. Null models suggest that stochastic processes governed the assembly of biofilm communities of decaying leaves in vitro in the early stages of biofilm formation and were further shaped by niche-associated factors.}, } @article {pmid38508759, year = {2024}, author = {Hamada, S and Minami, S and Gomi, M}, title = {Heparinoid enhances the efficacy of a bactericidal agent by preventing Cutibacterium acnes biofilm formation via quorum sensing inhibition.}, journal = {Journal of microorganism control}, volume = {29}, number = {1}, pages = {27-31}, doi = {10.4265/jmc.29.1_27}, pmid = {38508759}, issn = {2758-6391}, abstract = {Cutibacterium acnes is an opportunistic pathogen in acne vulgaris. C. acnes produces autoinducer-2 (AI-2）, a signaling molecule used for communication known as quorum sensing (QS）. In C. acnes, QS reportedly upregulates biofilm formation leading to resistance against bactericidal agents. In this study, we analyzed how heparinoid affected QS and biofilm formation of the opportunistic pathogen C. acnes. We also verified whether heparinoid would suppress biofilm formation and enhance the efficacy of the bactericidal agent 4-isopropyl-3-methylphenol (IPMP) against C. acnes biofilms. We ran an AI-2 bioassay using Vibrio harveyi ATCC BBA-1121. Heparinoid exhibited inhibitory activity against AI-2 at concentrations of 0.003-0.005%, suggesting an AI-2 analog-derived or C. acnes culture supernatant-derived inhibition of the AI-2 activity. To evaluate how heparinoid suppresses biofilm formation in C. acnes, we completed a biofilm assay in 96-well plates. We also evaluated the bactericidal activity of IPMP against the C. acnes biofilm prepared with or without heparinoid. Heparinoid inhibited C. acnes biofilm formation and IPMP bactericidal efficacy increased upon heparinoid-mediated suppression of biofilm formation. In this study, we clarified that heparinoid inhibits the AI-2-mediated QS of C. acnes, thereby suppressing biofilm formation and increasing IPMP bactericidal efficacy, potentially suppressing acne vulgaris.}, } @article {pmid38507111, year = {2024}, author = {Choi, CH and Mun, S and Oh, MH}, title = {Identification and characterization of Acinetobacter nosocomialis BfmRS, two-component regulatory system, essential for biofilm development.}, journal = {Genes & genomics}, volume = {}, number = {}, pages = {}, pmid = {38507111}, issn = {2092-9293}, support = {R202100704//Dankook University/ ; }, abstract = {BACKGROUND: Biofilm development by bacteria is considered to be an essential stage in the bacterial infection. Acinetobacter nosocomialis is an important nosocomial pathogen causing a variety of human infections. However, characteristics and specific determinants of biofilm development have been poorly characterized in A. nosocomialis.

OBJECTIVE: The aim of this study was to investigate the factors involved in the biofilm development by A. nosocomialis.

METHODS: Library of random transposon mutants was constructed using the Tn5 mutagenesis. The mutant strains, in which the ability of biofilm formation was significantly impaired, were screened by gentian violet staining. The roles of BfmR and BfmS were determined by constructing a bfmR and bfmS deletion mutant and analyzing the effects of bfmR and bfmS mutation on the biofilm development and motility of A. nosocomialis.

RESULTS: We identified a biofilm-defective mutant in which a transposon insertion inactivated an open reading frame encoding the BfmR in a two-component regulatory system consisting of BfmR and BfmS. The bfmR mutant revealed a significant reduction in biofilm formation and motility compared to wild-type strain. Deficiency in the biofilm formation and motility of the bfmR mutant was restored by single copy bfmR complementation. In contrast, the bfmS mutant had no effect on biofilm formation.

CONCLUSION: A. nosocomialis has a two-component regulatory system, BfmRS. BfmR is a response regulator required for the initial attachment and maturation of biofilm during the biofilm development as well as the bacterial growth. BfmR could be a potential drug target for A. nosocomialis infection.}, } @article {pmid38506718, year = {2024}, author = {Jha, NK and Gopu, V and Sivasankar, C and Singh, SR and Devi, PB and Murali, A and Shetty, PH}, title = {In vitro and in silico assessment of anti-biofilm and anti-quorum sensing properties of 2,4-Di-tert butylphenol against Acinetobacter baumannii.}, journal = {Journal of medical microbiology}, volume = {73}, number = {3}, pages = {}, doi = {10.1099/jmm.0.001813}, pmid = {38506718}, issn = {1473-5644}, mesh = {*Acinetobacter baumannii ; Biofilms ; Phenols/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Salts ; }, abstract = {Introduction. Acinetobacter baumannii is a nosocomial pathogen with a high potential to cause food-borne infections. It is designated as a critical pathogen by the World Health Organization due to its multi-drug resistance and mortalities reported. Biofilm governs major virulence factors, which promotes drug resistance in A. baumannii. Thus, a compound with minimum selection pressure on the pathogen can be helpful to breach biofilm-related virulence.Hypothesis/Gap Statement. To identify anti-biofilm and anti-virulent metabolites from extracts of wild Mangifera indica (mango) brine pickle bacteria that diminishes pathogenesis and resistance of A. baumannii.Aim. This study reports anti-biofilm and anti-quorum sensing (QS) efficacy of secondary metabolites from bacterial isolates of fermented food origin.Method. Cell-free supernatants (CFS) of 13 bacterial isolates from fermented mango brine pickles were screened for their efficiency in inhibiting biofilm formation and GC-MS was used to identify its metabolites. Anti-biofilm metabolite was tested on early and mature biofilms, pellicle formation, extra polymeric substances (EPS), cellular adherence, motility and resistance of A. baumannii. Gene expression and in silico studies were also carried out to validate the compounds efficacy.Results. CFS of TMP6b identified as Bacillus vallismortis, inhibited biofilm production (83.02 %). Of these, major compound was identified as 2,4-Di-tert-butyl phenol (2,4-DBP). At sub-lethal concentrations, 2,4-DBP disrupted both early and mature biofilm formation. Treatment with 2,4-DBP destructed in situ biofilm formed on glass and plastic. In addition, key virulence traits like pellicle (77.5 %), surfactant (95.3 %), EPS production (3-fold) and cell adherence (65.55 %) reduced significantly. A. baumannii cells treated with 2,4-DBP showed enhanced sensitivity towards antibiotics, oxide radicals and blood cells. Expression of biofilm-concomitant virulence genes like csuA/B, pgaC, pgaA, bap, bfmR, katE and ompA along with QS genes abaI, abaR significantly decreased. The in silico studies further validated the higher binding affinity of 2,4-DBP to the AbaR protein than the cognate ligand molecule.Conclusion. To our knowledge, this is the first report to demonstrate 2,4- DBP has anti-pathogenic potential alone and with antibiotics by in vitro, and in silico studies against A. baumannii. It also indicates its potential use in therapeutics and bio-preservatives.}, } @article {pmid38505856, year = {2024}, author = {Canale, V and Skiba-Kurek, I and Klesiewicz, K and Papież, M and Ropek, M and Pomierny, B and Piska, K and Koczurkiewicz-Adamczyk, P and Empel, J and Karczewska, E and Zajdel, P}, title = {Improving Activity of New Arylurea Agents against Multidrug-Resistant and Biofilm-Producing Staphylococcus epidermidis.}, journal = {ACS medicinal chemistry letters}, volume = {15}, number = {3}, pages = {369-375}, pmid = {38505856}, issn = {1948-5875}, abstract = {Multidrug-resistant (MDR) strains of Staphylococcus epidermidis (S. epidermidis), prevalent in hospital environments, contribute to increased morbidity and mortality, especially among newborns, posing a critical concern for neonatal sepsis. In response to the pressing demand for novel antibacterial therapies, we present findings from synthetic chemistry and structure-activity relationship studies focused on arylsulfonamide/arylurea derivatives of aryloxy[1-(thien-2-yl)propyl]piperidines. Through bioisosteric replacement of the sulfonamide fragment with a urea moiety, compound 25 was identified, demonstrating potent bacteriostatic activity against clinical multidrug-resistant S. epidermidis strains (MIC50 and MIC90 = 1.6 and 3.125 μg/mL). Importantly, it showed activity against linezolid-resistant strains and exhibited selectivity over mammalian cells. Compound 25 displayed antibiofilm-forming properties against clinical S. epidermidis strains and demonstrated the capacity to eliminate existing biofilm layers. Additionally, it induced complete depolarization of the bacterial membrane in clinical S. epidermidis strains. In light of these findings, targeting bacterial cell membranes with compound 25 emerges as a promising strategy in the fight against multidrug-resistant S. epidermidis strains.}, } @article {pmid38505565, year = {2024}, author = {Wang, L and Chen, QW and Qin, YC and Yi, XL and Zeng, H}, title = {Analysis of carbapenem-resistant Acinetobacter baumannii carbapenemase gene distribution and biofilm formation.}, journal = {International journal of molecular epidemiology and genetics}, volume = {15}, number = {1}, pages = {1-11}, pmid = {38505565}, issn = {1948-1756}, abstract = {OBJECTIVE: In recent years, Acinetobacter baumannii has been appearing in hospitals with high drug resistance and strong vitality, which brings many difficulties to clinical treatment. In this study, 255 strains of A. baumannii were isolated from Youjiang Medical University for Nationalities Affiliated Hospital clinical samples and found to be highly resistant to carbapenems. The drug resistance, biofilm-forming ability, and carbapenase gene distribution of 145 carbapenem-resistant A. baumannii (CRAB) strains were analyzed statistically.

METHODS: The clinically isolated strains were detected using Vitek mass spectrometry and Vitek2-compact for bacterial identification and susceptibility testing, respectively. The biofilms of clinical isolates were quantitatively detected by microplate crystal violet staining, and qualitatively observed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). And the common carbapenemase genes were detected by polymerase chain reaction (PCR).

RESULTS: The 255 clinical isolates from the Youjiang District of western Guangxi Province had a high resistance rate to carbapenems antibiotics. The main specimens were from the intensive care unit (49%), and the most important specimens were sputum specimens (80%). All 145 strains of CRAB produced different degrees of biofilm, and six carbapenenase genes were detected. We found that there were significant differences in biofilm formation between resistant and sensitive strains of tobramycin, levofloxacin, ciprofloxacin, tigecycline, and doxycycline (P<0.05). The distribution of blaOXA-23 and blaOXA51 genes was significantly different from CRAB biofilm formation (P<0.05). In addition, AmpC, blaOXA-23, blaOXA-51, and TEM genes were more distributed in antibiotic-resistant strains.

CONCLUSION: The clinical strains have a high resistance rate to carbapenems, and the CRAB with blaOXA-51 and blaOXA-23 genes has a high resistance to antibiotics and a strong biofilm.}, } @article {pmid38505547, year = {2024}, author = {Wallart, L and Ben Mlouka, MA and Saffiedine, B and Coquet, L and Le, H and Hardouin, J and Jouenne, T and Phan, G and Kiefer-Meyer, MC and Girard, E and Broutin, I and Cosette, P}, title = {BacA: a possible regulator that contributes to the biofilm formation of Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1332448}, pmid = {38505547}, issn = {1664-302X}, abstract = {Previously, we pointed out in P. aeruginosa PAO1 biofilm cells the accumulation of a hypothetical protein named PA3731 and showed that the deletion of the corresponding gene impacted its biofilm formation capacity. PA3731 belongs to a cluster of 4 genes (pa3732 to pa3729) that we named bac for "Biofilm Associated Cluster." The present study focuses on the PA14_16140 protein, i.e., the PA3732 (BacA) homolog in the PA14 strain. The role of BacA in rhamnolipid secretion, biofilm formation and virulence, was confirmed by phenotypic experiments with a bacA mutant. Additional investigations allow to advance that the bac system involves in fact 6 genes organized in operon, i.e., bacA to bacF. At a molecular level, quantitative proteomic studies revealed an accumulation of the BAC cognate partners by the bacA sessile mutant, suggesting a negative control of BacA toward the bac operon. Finally, a first crystallographic structure of BacA was obtained revealing a structure homologous to chaperones or/and regulatory proteins.}, } @article {pmid38502922, year = {2024}, author = {Zhang, L and Graham, N and Li, G and Zhu, Y and Yu, W}, title = {Excessive Ozonation Stress Triggers Severe Membrane Biofilm Accumulation and Fouling.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c10429}, pmid = {38502922}, issn = {1520-5851}, abstract = {The established benefits of ozone on microbial pathogen inactivation, natural organic matter degradation, and inorganic/organic contaminant oxidation have favored its application in drinking water treatment. However, viable bacteria are still present after the ozonation of raw water, bringing a potential risk to membrane filtration systems in terms of biofilm accumulation and fouling. In this study, we shed light on the role of the specific ozone dose (0.5 mg-O3/mg-C) in biofilm accumulation during long-term membrane ultrafiltration. Results demonstrated that ozonation transformed the molecular structure of influent dissolved organic matter (DOM), producing fractions that were highly bioavailable at a specific ozone dose of 0.5, which was inferred to be a turning point. With the increase of the specific ozone dose, the biofilm microbial consortium was substantially shifted, demonstrating a decrease in richness and diversity. Unexpectedly, the opportunistic pathogen Legionella was stimulated and occurred in approximately 40% relative abundance at the higher specific ozone dose of 1. Accordingly, the membrane filtration system with a specific ozone dose of 0.5 presented a lower biofilm thickness, a weaker fluorescence intensity, smaller concentrations of polysaccharides and proteins, and a lower Raman activity, leading to a lower hydraulic resistance, compared to that with a specific ozone dose of 1. Our findings highlight the interaction mechanism between molecular-level DOM composition, biofilm microbial consortium, and membrane filtration performance, which provides an in-depth understanding of the impact of ozonation on biofilm accumulation.}, } @article {pmid38501832, year = {2024}, author = {Pan, S and Underhill, SAM and Hamm, CW and Stover, MA and Butler, DR and Shults, CA and Manjarrez, JR and Cabeen, MT}, title = {Glycerol metabolism impacts biofilm phenotypes and virulence in Pseudomonas aeruginosa via the Entner-Doudoroff pathway.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0078623}, doi = {10.1128/msphere.00786-23}, pmid = {38501832}, issn = {2379-5042}, abstract = {Pseudomonas aeruginosa is a ubiquitous bacterium and a notorious opportunistic pathogen that forms biofilm structures in response to many environmental cues. Biofilm formation includes attachment to surfaces and the production of the exopolysaccharide Pel, which is present in both the PAO1 and PA14 laboratory strains of P. aeruginosa. Biofilms help protect bacterial cells from host defenses and antibiotics and abet infection. The carbon source used by the cells also influences biofilm, but these effects have not been deeply studied. We show here that glycerol, which can be liberated from host surfactants during infection, encourages surface attachment and magnifies colony morphology differences. We find that glycerol kinase is important but not essential for glycerol utilization and relatively unimportant for biofilm behaviors. Among downstream enzymes predicted to take part in glycerol utilization, Edd stood out as being important for glycerol utilization and for enhanced biofilm phenotypes in the presence of glycerol. Thus, gluconeogenesis and catabolism of anabolically produced glucose appear to impact not only the utilization of glycerol but also glycerol-stimulated biofilm phenotypes. Finally, waxworm moth larvae and nematode infection models reveal that interruption of the Entner-Doudoroff pathway, but not abrogation of glycerol phosphorylation, unexpectedly increases P. aeruginosa lethality in both acute and chronic infections, even while stimulating a stronger immune response by Caenorhabditis elegans.IMPORTANCEPseudomonas aeruginosa, the ubiquitous environmental bacterium and human pathogen, forms multicellular communities known as biofilms in response to various stimuli. We find that glycerol, a common carbon source that bacteria can use for energy and biosynthesis, encourages biofilm behaviors such as surface attachment and colony wrinkling by P. aeruginosa. Glycerol can be derived from surfactants that are present in the human lungs, a common infection site. Glycerol-stimulated biofilm phenotypes do not depend on phosphorylation of glycerol but are surprisingly impacted by a glucose breakdown pathway, suggesting that it is glycerol utilization, and not its mere presence or cellular import, that stimulates biofilm phenotypes. Moreover, the same mutations that block glycerol-stimulated biofilm phenotypes also impact P. aeruginosa virulence in both acute and chronic animal models. Notably, a glucose-breakdown mutant (Δedd) counteracts biofilm phenotypes but shows enhanced virulence and stimulates a stronger immune response in Caenorhabditis elegans.}, } @article {pmid38499092, year = {2024}, author = {Wang, Y and Zhao, X and Zhou, X and Dai, J and Hu, X and Piao, Y and Zu, G and Xiao, J and Shi, K and Liu, Y and Li, Y and Shi, L}, title = {A supramolecular hydrogel dressing with antibacterial, immunoregulation, and pro-regeneration ability for biofilm-associated wound healing.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {368}, number = {}, pages = {740-755}, doi = {10.1016/j.jconrel.2024.03.024}, pmid = {38499092}, issn = {1873-4995}, abstract = {Chronic wound treatment has emerged as a significant healthcare concern worldwide due to its substantial economic burden and the limited effectiveness of current treatments. Effective management of biofilm infections, regulation of excessive oxidative stress, and promotion of tissue regeneration are crucial for addressing chronic wounds. Hydrogel stands out as a promising candidate for chronic wound treatment. However, its clinical application is hindered by the difficulty in designing and fabricating easily and conveniently. To overcome these obstacles, we present a supermolecular G-quadruplex hydrogel with the desired multifunction via a dynamic covalent strategy and Hoogsteen-type hydrogen bonding. The G-quadruplex hydrogel is made from the self-assembly of guanosine, 2-formylphenyboronic acid, polyethylenimine, and potassium chloride, employing dynamic covalent strategy and Hoogsteen-type hydrogen bonding. In the acidic/oxidative microenvironment associated with bacterial infections, the hydrogel undergoes controlled degradation, releasing the polyethylenimine domain, which effectively eliminates bacteria. Furthermore, nanocomplexes comprising guanosine monophosphate and manganese sulfate are incorporated into the hydrogel skeleton, endowing it with the ability to scavenge reactive oxygen species and modulate macrophages. Additionally, the integration of basic fibroblast growth factor into the G-quadruplex skeleton through dynamic covalent bonds facilitates controlled tissue regeneration. In summary, the facile preparation process and the incorporation of multiple functionalities render the G-quadruplex hydrogel a highly promising candidate for advanced wound dressing. It holds great potential to transition from laboratory research to clinical practice, addressing the pressing needs of chronic wound management.}, } @article {pmid38498718, year = {2024}, author = {Karbelkar, AA and Font, M and Smith, TJ and Sondermann, H and O'Toole, GA}, title = {Reconstitution of a biofilm adhesin system from a sulfate-reducing bacterium in Pseudomonas fluorescens.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {121}, number = {13}, pages = {e2320410121}, doi = {10.1073/pnas.2320410121}, pmid = {38498718}, issn = {1091-6490}, support = {R01 GM123609/GM/NIGMS NIH HHS/United States ; }, abstract = {Biofilms of sulfate-reducing bacterium (SRB) like Desulfovibrio vulgaris Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses. Although the mechanisms of biofilm formation by DvH are not yet well understood, recent studies indicate the large adhesin, DvhA, is a key determinant of biofilm formation. The dvhA gene neighborhood resembles the biofilm-regulating Lap system of Pseudomonas fluorescens but is curiously missing the c-di-GMP-binding regulator LapD. Instead, DvH encodes an evolutionarily unrelated c-di-GMP-binding protein (DVU1020) that we hypothesized is functionally analogous to LapD. To study this unusual Lap system and overcome experimental limitations with the slow-growing anaerobe DvH, we reconstituted its predicted SRB Lap system in a P. fluorescens strain lacking its native Lap regulatory components (ΔlapGΔlapD). Our data support the model that DvhA is a cell surface-associated LapA-like adhesin with a N-terminal "retention module" and that DvhA is released from the cell surface upon cleavage by the LapG-like protease DvhG. Further, we demonstrate DVU1020 (named here DvhD) represents a distinct class of c-di-GMP-binding, biofilm-regulating proteins that regulates DvhG activity in response to intracellular levels of this second messenger. This study provides insight into the key players responsible for biofilm formation by DvH, thereby expanding our understanding of Lap-like systems.}, } @article {pmid38497440, year = {2024}, author = {Matoso, FB and Montagner, F and Grecca, FS and Rampelotto, PH and Kopper, PMP}, title = {Microbial composition and diversity in intraradicular biofilm formed in situ: New concepts based on next-generation sequencing.}, journal = {Molecular oral microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/omi.12462}, pmid = {38497440}, issn = {2041-1014}, abstract = {This study aimed to characterize the taxonomic composition of intraradicular multispecies biofilms (IMBs) formed in situ in a model to reproduce clinical conditions. Twelve palatal roots of maxillary molars had its canals prepared. Two roots were randomly selected to sterility control. Ten intraoral prosthetic appliances with lateral slots were fabricated. The roots were positioned in the slots with the canal access open to the oral cavity. Eight volunteers wore the appliance for 21 days, and two wore it at two different time points. One root from each appliance was removed and stored at -20°C until DNA extraction and sequencing (n = 10). Biofilm was analyzed using next-generation sequencing and bioinformatics. The V4 hyper-variable region of the 16SrRNA gene was amplified and sequenced. For data analyses, the mothur pipeline was used for 16SrRNA processing, and subsequent analyses of the sequence dataset were performed in R using the MicrobiomeAnalyst R package. The taxonomy-based analysis of bacterial communities identified 562 operational taxonomic units (OTUs), which belonged to 93 genera, 44 families, and 8 phyla. Bacterial colonization was different for each biofilm, and samples did not have the same group of bacteria. Alpha and beta diversity analysis revealed some general patterns of sample clustering. A core microbiome of prevalent OTUs and genera was identified. IMBs were heterogeneous when analyzed individually, but some diversity patterns were found after sample clustering. The experimental model seemed to reproduce the actual biofilm composition in endodontic infections, which suggests that it may be used to evaluate disinfection protocols.}, } @article {pmid38496814, year = {2024}, author = {Ibrahim, GI and Jawad, HA}, title = {Eradication of mature biofilm from the isthmus region using Er, Cr: YSGG Laser as an activator of 2% chlorhexidine gluconate.}, journal = {Journal of clinical and experimental dentistry}, volume = {16}, number = {2}, pages = {e159-e165}, pmid = {38496814}, issn = {1989-5488}, abstract = {BACKGROUND: Challenges in the root canal system, such as isthmus, may limit the action of endodontic equipment and irrigation solutions, so using laser agitation is recommended to upgrade the removal of microbial biofilm. The objective of this study is to assess the effectiveness of the laser in photon-induced photoacoustic streaming protocol agitation of 2% chlorohexidine gluconate in removing mature biofilm in complex root canal systems.

MATERIAL AND METHODS: Seventy-five mesial roots of the lower first and second molars were separated and cultivated with Enterococcus faecalis bacteria for 30 days (except for the negative control group samples). The samples were divided into four groups (n=15), one group acted as a positive control, other groups were irrigated with 2% chlorohexidine gluconate, some of them were agitated with a passive ultrasonic device, while the other samples were agitated by an Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser in photon-induced photoacoustic streaming protocol. An atomic force microscope was used as a new method to get the results in the isthmus area; A scanning electron microscope was also used in the study to examine the samples before and after the treatment. Statistical Package for Social Sciences software was used to collect and analyze data, and two-way ANOVA was used to compare the means of the test groups.

RESULTS: According to the atomic force microscope and scanning electron microscope analyses, Erbium laser and passive ultrasonic activation groups showed higher antimicrobial efficacy than the syringe irrigation group (p<0.05).

CONCLUSIONS: According to the study's results, the agitation of chlorohexidine gluconate fluid by Erbium laser in photon-induced photoacoustic streaming at 0.75 W offers better Enterococcus faecalis biofilm removal in the difficult-to-reach areas of lower first and second molars. Key words:Atomic force microscope, 2% chlorhexidine gluconate, Enterococcus faecalis, Erbium, chromium-doped yttrium, scandium, gallium, garnet laser, passive ultrasonic.}, } @article {pmid38495771, year = {2024}, author = {Alidokht, L and Fitzpatrick, K and Butler, C and Hunsucker, KZ and Braga, C and Maza, WA and Fears, KP and Arekhi, M and Lanzarini-Lopes, M}, title = {UV emitting glass: A promising strategy for biofilm inhibition on transparent surfaces.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100186}, pmid = {38495771}, issn = {2590-2075}, abstract = {Marine biofouling causes serious environmental problems and has adverse impacts on the maritime industry. Biofouling on windows and optical equipment reduces surface transparency, limiting their application for on-site monitoring or continuous measurement. This work illustrates that UV emitting glasses (UEGs) can prevent the establishment and growth of biofilm on the illuminated surfaces. Specifically, this paper describes how UEGs are enabled by innovatively modifying the surfaces of the glass with light scattering particles. Modification of glass surface with silica nanoparticles at a concentration 26.5 μg/cm[2] resulted in over ten-fold increase in UV irradiance, while maintaining satisfactory visible and IR transparency metrics of over 99 %. The UEG reduced visible biological growth by 98 % and resulted in a decrease of 1.79 log in detected colony forming units when compared to the control during a 20 day submersion at Port Canaveral, Florida, United States. These findings serve as strong evidence that UV emitting glass should be explored as a promising approach for biofilm inhibition on transparent surfaces.}, } @article {pmid38495770, year = {2024}, author = {Tian, S and Shi, L and Ren, Y and van der Mei, HC and Busscher, HJ}, title = {A normalized parameter for comparison of biofilm dispersants in vitro.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100188}, pmid = {38495770}, issn = {2590-2075}, abstract = {Dispersal of infectious biofilms increases bacterial concentrations in blood. To prevent sepsis, the strength of a dispersant should be limited to allow the immune system to remove dispersed bacteria from blood, preferably without antibiotic administration. Biofilm bacteria are held together by extracellular polymeric substances that can be degraded by dispersants. Currently, comparison of the strength of dispersants is not possible by lack of a suitable comparison parameter. Here, a biofilm dispersal parameter is proposed that accounts for differences in initial biofilm properties, dispersant concentration and exposure time by using PBS as a control and normalizing outcomes with respect to concentration and time. The parameter yielded near-identical values based on dispersant-induced reductions in biomass or biofilm colony-forming-units and appeared strain-dependent across pathogens. The parameter as proposed is largely independent of experimental methods and conditions and suitable for comparing different dispersants with respect to different causative strains in particular types of infection.}, } @article {pmid38495170, year = {2024}, author = {Khanna, N and Girija A S, S and Priyadharsini J, V}, title = {Detection of the early putative biofilm marker pgaB among the MDR strains of A.baumannii.}, journal = {Heliyon}, volume = {10}, number = {5}, pages = {e27020}, pmid = {38495170}, issn = {2405-8440}, abstract = {BACKGROUND: pgaB associated biofilm formation in Acinetobacter baumannii enhances the virulence in concert with the high propensity of drug resistance. This research is thus aimed to characterize the pgaB gene molecularly and to examine its co-occurrence with MDR.

METHODOLOGY: MDR strains of A. baumannii (N = 73) were selected to detect the formation of biofilms. Genomic DNA was extracted further and screened for pgaB followed by amplicon sequencing from the representative strains. Frequency of its distribution in different groups of drug resistant strains at a significant p-value of <0.05 was further checked.

RESULTS: The biofilm assay showed high, low and negative biofilm formers in 58.9%, 31.5% and 0.9% of the strains respectively. The pgaB gene was detected in 14 strains of MDR A. baumannii (19.17%). Co-occurrence of pgaB gene was seen in all the strains that showed resistance to β-lactam inhibitors, cephems, carbapenems, fluoroquinolones and folates followed by 96% for the aminoglycosides and 25% in the efflux pump groups.

CONCLUSION: The study findings showed the occurrence of biofilms associated with pgaB in MDR A. baumannii strains. The results also suggest to track its role in varying the pattern of drug resistance with further experimentation.}, } @article {pmid38494241, year = {2024}, author = {Liu, Y and Li, R and Zhang, Y and Jiao, S and Xu, T and Zhou, Y and Wang, Y and Wei, J and Du, W and Fujita, M and Du, Y and Wang, ZA}, title = {Unveiling the inverse antimicrobial impact of a hetero-chitooligosaccharide on Candida tropicalis growth and biofilm formation.}, journal = {Carbohydrate polymers}, volume = {333}, number = {}, pages = {121999}, doi = {10.1016/j.carbpol.2024.121999}, pmid = {38494241}, issn = {1879-1344}, abstract = {Chitosan and chitooligosaccharide (COS) are renowned for their potent antimicrobial prowess, yet the precise antimicrobial efficacy of COS remains elusive due to scant structural information about the utilized saccharides. This study delves into the antimicrobial potential of COS, spotlighting a distinct hetero-chitooligosaccharide dubbed DACOS. In contrast to other COS, DACOS remarkably fosters the growth of Candida tropicalis planktonic cells and fungal biofilms. Employing gradient alcohol precipitation, DACOS was fractionated, unveiling diverse structural characteristics and differential impacts on C. tropicalis. Notably, in a murine model of systemic candidiasis, DACOS, particularly its 70 % alcohol precipitates, manifests a promotive effect on Candida infection. This research unveils a new pathway for exploring the intricate nexus between the structural attributes of chitosan oligosaccharides and their physiological repercussions, underscoring the imperative of crafting chitosan and COS with meticulously defined structural configurations.}, } @article {pmid38494090, year = {2024}, author = {Cakin, I and Morrissey, B and Gordon, M and Gaffney, PPJ and Marcello, L and Macgregor, K and Taggart, MA}, title = {Comparing DNA isolation and sequencing strategies for 16S rRNA gene amplicon analysis in biofilm containing environments.}, journal = {Journal of microbiological methods}, volume = {}, number = {}, pages = {106921}, doi = {10.1016/j.mimet.2024.106921}, pmid = {38494090}, issn = {1872-8359}, abstract = {Bacteria are primarily responsible for biological water treatment processes in constructed wetland systems. Gravel in constructed wetlands serves as an essential substrate onto which complex bacterial biofilms may successfully grow and evolve. To fully understand the bacterial community in these systems it is crucial to properly isolate biofilms and process DNA from such substrates. This study looked at how best to isolate bacterial biofilms from gravel substrates in terms of bacterial richness. It considered factors including the duration of agitation during extraction, extraction temperature, and enzyme usage. Further, the 16S taxonomy data subsequently produced from Illumina MiSeq reads (using the SILVA 132 ribosomal RNA (rRNA) database on the DADA2 pipeline) were compared with the 16S data produced from Oxford Nanopore Technologies (ONT) MinION reads (using the NCBI 16S database on the EPI2ME pipeline). Finally, performance was tested by comparing the taxonomy data generated from the Illumina MiSeq and ONT MinION reads using the same (SILVA 132) database. We found no significant differences in the effective number of species observed when using different bacterial biofilm detachment techniques. However, enzyme treatment enhanced the total concentration of DNA. In terms of wetland community profiles, relative abundance differences within each sample type were clearer at the genus level. For genus-level taxonomic classification, MinION sequencing with the EPI2ME pipeline (NCBI database) produced bacterial abundance information that was poorly correlated with that from the Illumina MiSeq and DADA2 pipelines (SILVA132 database). When using the same database for each sequencing technology (SILVA132), the correlation between relative abundances at genus-level improved from negligible to moderate. This study provides detailed information of value to researchers working on constructed wetlands regarding efficient biofilm detachment techniques for DNA isolation and 16 s metabarcoding platforms for sequencing and data analysis.}, } @article {pmid38494030, year = {2024}, author = {Alrammah, F and Xu, L and Patel, N and Kontis, N and Rosado, A and Gu, T}, title = {Conductive magnetic nanowires accelerated electron transfer between C1020 carbon steel and Desulfovibrio vulgaris biofilm.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {171763}, doi = {10.1016/j.scitotenv.2024.171763}, pmid = {38494030}, issn = {1879-1026}, abstract = {Microbial biofilms are behind microbiologically influenced corrosion (MIC). Sessile cells in biofilms are many times more concentrated volumetrically than planktonic cells in the bulk fluids, thus providing locally high concentrations of chemicals. More importantly, "electroactive" sessile cells in biofilms are capable of utilizing extracellularly supplied electrons (e.g., from elemental Fe) for intracellular reduction of an oxidant such as sulfate in energy metabolism. MIC directly caused by anaerobic biofilms is classified into two main types based on their mechanisms: extracellular electron transfer MIC (EET-MIC) and metabolite MIC (M-MIC). Sulfate-reducing bacteria (SRB) are notorious for their corrosivity. They can cause EET-MIC in carbon steel, but they can also secrete biogenic H2S to corrode other metals such as Cu directly via M-MIC. This study investigated the use of conductive magnetic nanowires as electron mediators to accelerate and thus identify EET-MIC of C1020 by Desulfovibrio vulgaris. The presence of 40 ppm (w/w) nanowires in ATCC 1249 culture medium at 37 °C resulted in 45 % higher weight loss and 57 % deeper corrosion pits after 7-day incubation. Electrochemical tests using linear polarization resistance and potentiodynamic polarization supported the weight loss data trend. These findings suggest that conductive magnetic nanowires can be employed to identify EET-MIC. The use of insoluble 2 μm long nanowires proved that the extracellular section of the electron transfer process is a bottleneck in SRB MIC of carbon steel.}, } @article {pmid38494003, year = {2024}, author = {Xiao, K and Abbt-Braun, G and Pleitner, R and Horn, H}, title = {Effect of ciprofloxacin on the one-stage partial nitrification and anammox biofilm system: A multivariate analysis focusing on size-fractionated organic components.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141731}, doi = {10.1016/j.chemosphere.2024.141731}, pmid = {38494003}, issn = {1879-1298}, abstract = {The impact of ciprofloxacin (CIP) in the partial nitrification and anammox biofilm system was investigated by multivariate analysis, focusing on size-fractionated organic components. The CIP dose of 10 μg/L did not inhibit the total nitrogen (TN) removal efficiency, even though the abundance of antibiotic resistant genes (ARGs) (i.e., qnrD, qnrB, qnrA, qnrS, and arcA) was elevated. However, a gradual higher CIP dosing up to 100 μg/L inhibited the TN removal efficiency, while the abundance of ARGs was still increased. Moreover, both the TN removal efficiency and the abundant ARGs were dwindled at 470 μg/L of CIP. As the CIP dose increased from 0 to 100 μg/L, the abundance of high molecular weight (MW) fractions (14,000 to 87,000 Da; 1000 to 14,000 Da) and humic/fulvic acid-like components in the soluble extracellular polymeric substances (HSS) decreased, with more increases of low MW (84-1000 Da; less than 84 Da) fractions and soluble microbial by-products in soluble extracellular polymeric substances (SMPS). Continuously increasing the CIP dose till 470 μg/L, an inverse trend of the changes of these organic components was noted, along with clear reductions of the microbial diversity and richness, and the abundance of key functional genes responsible for nitrogen removal. The predominance of functional gene amoA (related with ammonia oxidizing bacteria) was more significantly with more distribution of SMPS with relatively low MW and less distribution of HSS with relatively high MW, as well as polymer decomposing microorganisms such as Bryobacteraceae and the unclassified Saprospirales.}, } @article {pmid38493904, year = {2024}, author = {Wei, PW and Wang, X and Wang, C and Chen, M and Liu, MZ and Liu, WX and He, YL and Xu, GB and Zheng, XH and Zhang, H and Liu, HM and Wang, B}, title = {Ginkgo biloba L. exocarp petroleum ether extract inhibits methicillin-resistant Staphylococcus aureus by modulating ion transport, virulence, and biofilm formation in vitro and in vivo.}, journal = {Journal of ethnopharmacology}, volume = {}, number = {}, pages = {117957}, doi = {10.1016/j.jep.2024.117957}, pmid = {38493904}, issn = {1872-7573}, abstract = {As reported in the Ancient Chinese Medicinal Books, Ginkgo biloba L. fruit has been used as a traditional Chinese medicine for the treatment asthma and cough or as a disinfectant. Our previous study demonstrated that G. biloba exocarp extract (GBEE), an extract of a traditional Chinese herb, inhibits the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms. However, GBEE is a crude extract that contains many components, and the underlying mechanisms of purified GBEE fractions extracted with solvents of different polarities are unknown.

AIM OF THE STUDY: This study aimed to investigate the different components in GBEE fractions extracted with solvents of different polarities and their antibacterial effects and mechanisms against MRSA and Staphylococcus haemolyticus biofilms both in vitro and in vivo.

METHODS: The components in different fractions were detected by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). Microbroth dilution assays and time growth curves were used to determine the antibacterial effects of the fractions on 15 clinical bacterial isolates. Crystal violet staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to identify the fractions that affected bacterial biofilm formation. The potential MRSA targets of the GBEE fraction obtained with petroleum ether (PE), denoted GBEE-PE, were screened by transcriptome sequencing, and the gene expression profile was verified by quantitative polymerase chain reaction (qPCR).

RESULTS: HPLC-HRMS analysis revealed that the four GBEE fractions (extracted with petroleum ether, ethyl acetate, n-butanol, and water) contained different ginkgo components, and the antibacterial effects decreased as the polarity of the extraction solvent increased. The antibacterial activity of GBEE-PE was greater than that of the GBEE fraction extracted with ethyl acetate (EA). GBEE-PE improved H. illucens survival and reduced MRSA colonization in model mouse organs. Crystal violet staining and SEM and TEM analyses revealed that GBEE-PE inhibited MRSA and S. haemolyticus biofilm formation. Transcriptional analysis revealed that GBEE-PE inhibits MRSA biofilms by altering ion transport, cell wall metabolism and virulence-related gene expression. In addition, the LO2 cell viability and H. illucens toxicity assay data showed that GBEE-PE at 20 mg/kg was nontoxic.

CONCLUSION: The GBEE fractions contained different components, and their antibacterial effects decreased with increases in the polarity of the extraction solvent. GBEE-PE limited MRSA growth and biofilm formation by affecting ion transport, cell wall synthesis, and virulence-related pathways. This research provides a more detailed overview of the mechanism by which GBEE-PE inhibits MRSA both in vitro and in vivo and suggests that GBEE-PE is a new prospective antimicrobial with the potential to be used in MRSA therapeutics in the future.}, } @article {pmid38493743, year = {2024}, author = {Li, Y and Dai, J and Ma, Y and Yao, Y and Yu, D and Shen, J and Wu, L}, title = {The mitigation potential of synergistic quorum quenching and antibacterial properties for biofilm proliferation and membrane biofouling.}, journal = {Water research}, volume = {255}, number = {}, pages = {121462}, doi = {10.1016/j.watres.2024.121462}, pmid = {38493743}, issn = {1879-2448}, abstract = {Biofouling has been a persistent problem hindering the application of membranes in water treatment, and quorum quenching has been identified as an effective method for mitigating biofouling, but surface accumulation of live bacteria still induces biofilm secretion, which poses a significant challenge for sustained prevention of membrane biofouling. In this study, we utilized quercetin, a typical flavonoid with the dual functions of quorum quenching and bacterial inactivation, to evaluate its role in preventing biofilm proliferation and against biofouling. Quercetin exhibited excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the decreased bioactivity was positively correlated with the quercetin concentration, with inhibition rates of 53.1 % and 57.4 %, respectively, at the experimental concentrations. The RT-qPCR results demonstrated that quercetin inhibited AI-2 of E. coli and AGR of S. aureus mediated quorum sensing system, and reduced the expression of genes such as adhesion, virulence, biofilm secretion, and key regulatory proteases. As a result, the bacterial growth cycle was retarded and the biomass and biofilm maturation cycles were alleviated with the synergistic effect of quorum quenching and antibacterial activity. In addition, membrane biofouling was significantly declined in the dynamic operation experiments, dead cells in the biofilm overwhelmingly dominated, and the final normalized water fluxes were increased by more than 49.9 % and 34.5 % for E. coli and S. aureus, respectively. This work demonstrates the potential for mitigating biofouling using protocols that quorum quenching and inactivate bacteria, also provides a unique and long-lasting strategy to alleviate membrane fouling.}, } @article {pmid38493145, year = {2024}, author = {Zhao, Y and Wu, Y and Xu, Q and Liu, Y and Song, Z and Han, H}, title = {H2O2 self-supplying and GSH-depleting nanosystem for amplified NIR mediated-chemodynamic therapy of MRSA biofilm-associated infections.}, journal = {Journal of nanobiotechnology}, volume = {22}, number = {1}, pages = {117}, pmid = {38493145}, issn = {1477-3155}, support = {22277036//National Natural Science Foundation of China/ ; }, abstract = {Reactive oxygen species (ROS) has emerged as potent therapeutic agents for biofilm-associated bacterial infections. Chemodynamic therapy (CDT), involving the generation of high-energy ROS, displays great potential in the therapy of bacterial infections. However, challenges such as insufficient hydrogen peroxide (H2O2) and over-expressed glutathione (GSH) levels within the microenvironment of bacterial biofilms severely limit the antibacterial efficacy of CDT. Herein, we have developed a multifunctional nanoplatform (CuS@CaO2@Dex) by integrating copper sulfide (CuS) and calcium peroxide (CaO2) into dextran (Dex)-coated nanoparticles. This innovative platform enhanced ROS generation for highly efficient biofilm elimination by simultaneously supplying H2O2 and depleting GSH. The Dex-coating facilitated the penetrability of CuS@CaO2@Dex into biofilms, while CaO2 generated a substantial amount of H2O2 in the acidic biofilm microenvironment. CuS, through a Fenton-like reaction, catalyzed the conversion of self-supplied H2O2 into hydroxyl radicals (•OH) and consumed the overexpressed GSH. Additionally, the incorporation of near-infrared II (NIR II) laser irradiation enhanced the photothermal properties of CuS, improving the catalytic efficiency of the Fenton-like reaction for enhanced antibacterial effects. In vivo experiments have demonstrated that CuS@CaO2@Dex exhibited remarkable antibacterial and antibiofilm efficacy, exceptional wound healing capabilities, and notable biosafety. In summary, the Dex-coated nanoplatform proposed in this study, with its self-sterilization capability through ROS, holds significant potential for future biomedical applications.}, } @article {pmid38492828, year = {2024}, author = {Malik, M and Das, S and Chakraborty, P and Paul, P and Roy, R and Das Gupta, A and Sarkar, S and Chatterjee, S and Maity, A and Dasgupta, M and Sarker, RK and Tribedi, P}, title = {Application of cuminaldehyde and ciprofloxacin for the effective control of biofilm assembly of Pseudomonas aeruginosa: A combinatorial study.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106624}, doi = {10.1016/j.micpath.2024.106624}, pmid = {38492828}, issn = {1096-1208}, abstract = {Pseudomonas aeruginosa is widely associated with biofilm-mediated antibiotic resistant chronic and acute infections which constitute a persistent healthcare challenges. Addressing this threat requires exploration of novel therapeutic strategies involving the combination of natural compounds and conventional antibiotics. Hence, our study has focused on two compounds; cuminaldehyde and ciprofloxacin, which were strategically combined to target the biofilm challenge of P. aeruginosa. The minimum inhibitory concentration (MIC) of cuminaldehyde and ciprofloxacin was found to be 400 μg/mL and 0.4 μg/mL, respectively. Moreover, the fractional inhibitory concentration index (FICI = 0.62) indicated an additive interaction prevailed between cuminaldehyde and ciprofloxacin. Subsequently, sub-MIC doses of cuminaldehyde (25 μg/mL) and ciprofloxacin (0.05 μg/mL) were selected for an array of antibiofilm assays which confirmed their biofilm inhibitory potential without exhibiting any antimicrobial activity. Furthermore, selected doses of the mentioned compounds could manage biofilm on catheter surface by inhibiting and disintegrating existing biofilm. Additionally, the test combination of the mentioned compounds reduced virulence factors secretion, accumulated reactive oxygen species and increased cell-membrane permeability. Thus, the combination of cuminaldehyde and ciprofloxacin demonstrates potential in combating biofilm-associated Pseudomonal threats.}, } @article {pmid38491527, year = {2024}, author = {Milech, A and Braga, CQ and Dos Santos Bermann, C and de Souza, JF and Fajardo, AR and Vianna, ÉS and Oliveira, CB}, title = {New artificial hematophagy system with attractive polymeric biofilm for maintenance of Culex quinquefasciatus (Diptera: Culicidae) in the laboratory.}, journal = {Parasites & vectors}, volume = {17}, number = {1}, pages = {136}, pmid = {38491527}, issn = {1756-3305}, abstract = {BACKGROUND: Maintaining mosquito colonies in the laboratory requires a blood supply so that females' oocytes can mature and oviposition can take place. In this study, a new artificial hematophagy system for colonization and maintenance of Culex quinquefasciatus in the laboratory was developed and tested.

METHODS: We developed an attractive polymeric biofilm including 25% L-lactic acid for use as a membrane in an artificial hematophagy system and compared the feeding rate of females with Parafilm-M[®]. We also evaluated the oviposition rate, larval survival and adult emergence of females fed through the attractive biofilm.

RESULTS: The average percentage of female Cx. quinquefasciatus fed through the attractive biofilm was 87%, while only 20% became engorged with Parafilm-M[®] (p < 0.0001). Feeding through the attractive biofilm developed in this study produced high levels of evaluated biological parameters; the percentage of egg laying by females that underwent artificial hematophagy through the biofilm was 90%, with an average of 158 eggs per raft. From these eggs, 97% of the larvae hatched, of which 95% reached the pupal stage. The adult emergence rate corresponded to 93% of pupae.

CONCLUSIONS: Insects fed with attractant through the biofilm system had a higher engorgement rate compared to those fed through Parafilm-M[®]. Our study is preliminary and suggests that polymeric biofilm has great potential for artificially feeding mosquitoes in the laboratory. Based on this research, new studies will be carried out with biofilm and different systems.}, } @article {pmid38490460, year = {2024}, author = {Zou, S and Ma, Y and Ding, W and Jiang, Y and Chen, X and Chen, J and Gao, H and Xue, Y and Zheng, Y}, title = {Efficient production of R-2-(4-hydroxyphenoxy) propionic acid by Beauveria bassiana using biofilm-based two-stage fermentation.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130588}, doi = {10.1016/j.biortech.2024.130588}, pmid = {38490460}, issn = {1873-2976}, abstract = {In this work, a novel biofilm-based fermentation of Beauveria bassiana was employed to convert R-2- phenoxypropionic acid (R-PPA) to R-2-(4-hydroxyphenoxy) propionic acid (R-HPPA). The biofilm culture model of Beauveria bassiana produced a significantly higher R-HPPA titer than the traditional submerged fermentation method. Mannitol dosage, tryptone dosage, and initial pH were the factors that played a significant role in biofilm formation and R-HPPA synthesis. Under the optimal conditions, the maximum R-HPPA titer and productivity approached 22.2 g/L and 3.2 g/(L·d), respectively. A two-stage bioreactor combining agitation and static incubation was developed to further increase R-HPPA production. The process was optimized to achieve 100 % conversion of R-PPA, with a maximum R-HPPA titer of 50 g/L and productivity of 3.8 g/(L·d). This newly developed biofilm-based two-stage fermentation process provides a promising strategy for the industrial production of R-HPPA and related hydroxylated aromatic compounds.}, } @article {pmid38490139, year = {2024}, author = {Zheng, Y and Zhang, W and Tang, B and Bin, L and Ding, J and Zheng, Y and Zhang, Z}, title = {Corrigendum to "Membrane fouling mechanism of biofilm-membrane bioreactor (BF-MBR): Pore blocking model and membrane cleaning" [Bioresour. Technol. 250 (2018) 398-405].}, journal = {Bioresource technology}, volume = {399}, number = {}, pages = {130564}, doi = {10.1016/j.biortech.2024.130564}, pmid = {38490139}, issn = {1873-2976}, } @article {pmid38489102, year = {2024}, author = {Tayyeb, JZ and Priya, M and Guru, A and Kishore Kumar, MS and Giri, J and Garg, A and Agrawal, R and Mat, KB and Arockiaraj, J}, title = {Multifunctional curcumin mediated zinc oxide nanoparticle enhancing biofilm inhibition and targeting apoptotic specific pathway in oral squamous carcinoma cells.}, journal = {Molecular biology reports}, volume = {51}, number = {1}, pages = {423}, pmid = {38489102}, issn = {1573-4978}, abstract = {BACKGROUND: Oral health remains a significant global concern with the prevalence of oral pathogens and the increasing incidence of oral cancer posing formidable challenges. Additionally, the emergence of antibiotic-resistant strains has complicated treatment strategies, emphasizing the urgent need for alternative therapeutic approaches. Recent research has explored the application of plant compounds mediated with nanotechnology in oral health, focusing on the antimicrobial and anticancer properties.

METHODS: In this study, curcumin (Cu)-mediated zinc oxide nanoparticles (ZnO NPs) were synthesized and characterized using SEM, EDAX, UV spectroscopy, FTIR, and XRD to validate their composition and structural features. The antioxidant and antimicrobial activity of ZnO-CU NPs was investigated through DPPH, ABTS, and zone of inhibition assays. Apoptotic assays and gene expression analysis were performed in KB oral squamous carcinoma cells to identify their anticancer activity.

RESULTS: ZnO-CU NPs showcased formidable antioxidant prowess in both DPPH and ABTS assays, signifying their potential as robust scavengers of free radicals. The determined minimal inhibitory concentration of 40 µg/mL against dental pathogens underscored the compelling antimicrobial attributes of ZnO-CU NPs. Furthermore, the interaction analysis revealed the superior binding affinity and intricate amino acid interactions of ZnO-CU NPs with receptors on dental pathogens. Moreover, in the realm of anticancer activity, ZnO-CU NPs exhibited a dose-dependent response against Human Oral Epidermal Carcinoma KB cells at concentrations of 10 µg/mL, 20 µg/mL, 40 µg/mL, and 80 µg/mL. Unraveling the intricate mechanism of apoptotic activity, ZnO-CU NPs orchestrated the upregulation of pivotal genes, including BCL2, BAX, and P53, within the KB cells.

CONCLUSIONS: This multifaceted approach, addressing both antimicrobial and anticancer activity, positions ZnO-CU NPs as a compelling avenue for advancing oral health, offering a comprehensive strategy for tackling both oral infections and cancer.}, } @article {pmid38489099, year = {2024}, author = {Abo-Alella, D and Abdelmoniem, W and Tantawy, E and Asaad, A}, title = {Biofilm-producing and carbapenems-resistant Escherichia coli nosocomial uropathogens: a cross-sectional study.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {38489099}, issn = {1618-1905}, abstract = {OBJECTIVES: This cross-sectional study aims to determine the incidence and potential risk factors associated with biofilm-producing uropathogenic Escherichia coli (UPEC) nosocomial strains from a tertiary care hospital and to examine the prospective correlation between biofilm generation and antibiotic resistance phenotypes and genotypes.

METHODS: A total of 130 UPEC nosocomial isolates were identified, their biofilm formation was quantified using a modified microtiter plate assay, and their antibiotic susceptibilities were assessed utilizing the disc diffusion method. Isolates were then subjected to PCR assays targeting blaKPC, blaVIM, blaIMP, and blaOXA48 genes.

RESULTS: Over half of the isolates (n = 76, 58.5%) were biofilm producers. Among 17 carbapenem-resistant isolates, 6 (42.9%) isolates harbored the blaOXA48 gene, and only 1 (9.1%) isolate was positive for the blaVIM gene. Prior antibiotic therapy (aOR 15.782, p 0.000) and diabetes mellitus DM (aOR 11.222, p 0.016) were the significant risk factors associated with biofilm production, as determined by logistic regression analysis of the data. In addition, gentamicin resistance was the only statistically significant antibiotic resistance pattern associated with biofilm production (aOR 9.113, p 0.02).

CONCLUSIONS: The findings of this study emphasize the significance of implementing proper infection control measures to avoid the horizontal spread of biofilm formation and associated antimicrobial resistance patterns among UPEC nosocomial strains.}, } @article {pmid38489041, year = {2024}, author = {Bhavya, JN and Anugna, SS and Premanath, R}, title = {Sub-inhibitory concentrations of colistin and imipenem impact the expression of biofilm-associated genes in Acinetobacter baumannii.}, journal = {Archives of microbiology}, volume = {206}, number = {4}, pages = {169}, pmid = {38489041}, issn = {1432-072X}, support = {N(DU)/RD/Grant/NUCSER/2020-20/04-9//Nitte research grant/ ; }, abstract = {Acinetobacter baumannii is an opportunistic pathogen that is responsible for nosocomial infections. Imipenem and colistin are drugs that are commonly used to treat severe infections caused by A. baumannii, such as sepsis, ventilator-associated pneumonia, and bacteremia. However, some strains of A. baumannii have become resistant to these drugs, which is a concern for public health. Biofilms produced by A. baumannii increase their resistance to antibiotics and the cells within the inner layers of biofilm are exposed to sub-inhibitory concentrations (sub-MICs) of antibiotics. There is limited information available regarding how the genes of A. baumannii are linked to biofilm formation when the bacteria are exposed to sub-MICs of imipenem and colistin. Thus, this study's objective was to explore this relationship by examining the genes involved in biofilm formation in A. baumannii when exposed to low levels of imipenem and colistin. The study found that exposing an isolate of A. baumannii to low levels of these drugs caused changes in their drug susceptibility pattern. The relative gene expression profiles of the biofilm-associated genes exhibited a change in their expression profile during short-term and long-term exposure. This study highlights the potential consequences of overuse and misuse of antibiotics, which can help bacteria become resistant to these drugs.}, } @article {pmid38488341, year = {2024}, author = {Gao, Q and Chu, X and Yang, J and Guo, Y and Guo, H and Qian, S and Yang, YW and Wang, B}, title = {An Antibiotic Nanobomb Constructed from pH-Responsive Chemical Bonds in Metal-Phenolic Network Nanoparticles for Biofilm Eradication and Corneal Ulcer Healing.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2309086}, doi = {10.1002/advs.202309086}, pmid = {38488341}, issn = {2198-3844}, support = {ZY2019017//Wenzhou key program of scientific and technological innovation/ ; 2021ZA091//Zhejiang Provincial Traditional Chinese Medicine Science and Technology Project/ ; LR21H180001//Natural Science Foundation of Zhejiang Province/ ; }, abstract = {In the treatment of refractory corneal ulcers caused by Pseudomonas aeruginosa, antibacterial drugs delivery faces the drawbacks of low permeability and short ocular surface retention time. Hence, novel positively-charged modular nanoparticles (NPs) are developed to load tobramycin (TOB) through a one-step self-assembly method based on metal-phenolic network and Schiff base reaction using 3,4,5-trihydroxybenzaldehyde (THBA), ε-poly-ʟ-lysine (EPL), and Cu[2+] as matrix components. In vitro antibacterial test demonstrates that THBA-Cu-TOB NPs exhibit efficient instantaneous sterilization owing to the rapid pH responsiveness to bacterial infections. Notably, only 2.6 µg mL[-1] TOP is needed to eradicate P. aeruginosa biofilm in the nano-formed THBA-Cu-TOB owing to the greatly enhanced penetration, which is only 1.6% the concentration of free TOB (160 µg mL[-1]). In animal experiments, THBA-Cu-TOB NPs show significant advantages in ocular surface retention, corneal permeability, rapid sterilization, and inflammation elimination. Based on molecular biology analysis, the toll-like receptor 4 and nuclear factor kappa B signaling pathways are greatly downregulated as well as the reduction of inflammatory cytokines secretions. Such a simple and modular strategy in constructing nano-drug delivery platform offers a new idea for toxicity reduction, physiological barrier penetration, and intelligent drug delivery.}, } @article {pmid38486820, year = {2024}, author = {Edayadulla, N and Divakaran, D and Chandraraj, SS and Suyambulingam, I and Jayamani, E and Sanjay, MR and Siengchin, S}, title = {Isolation and characterization of novel bioplasticizers from rose (Rosa damascena Mill.) petals and its suitability investigation for poly (butylene adipate-co-terephthalate) biofilm applications.}, journal = {3 Biotech}, volume = {14}, number = {4}, pages = {110}, doi = {10.1007/s13205-024-03956-1}, pmid = {38486820}, issn = {2190-572X}, abstract = {The current growing environmental awareness has forced the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. Rose petal plasticizers (RPP) act as an actual substitute for chemical plasticizers in this situation as they are biocompatible and biodegradable. Chemical procedures like amination, alkalization, and surface catalysis are used to extract the natural emollients from rose petals. XRD, FT-IR, and UV studies were used to understand the characteristics of the rose petal plasticizer. Based on the XRD data, the RPP's crystallinity size (CS) and crystallinity index (CI) values were determined to be 9.36 nm and 23.87%, respectively. The surface morphology of the isolated plasticizer is investigated using SEM, EDAX analysis and AFM. RPP surface pores with rough surfaces are visible in SEM images, which make them appropriate for plasticizing novel bioplastics with superior mechanical qualities. The plasticizer's heat degradation behaviour is investigated using thermogravimetric and differential thermogram analysis curves. Following the characterization of the synthesised molecules, the plasticization effect was examined using a biodegradable polymer matrix called poly (butylene adipate-co-terephthalate) (PBAT). The reinforcement interface was also examined using scanning electron microscopy analysis. RPP-reinforced films demonstrated greater flexibility and superior surface compatibility at a 5% loading compared to PBAT-only films. Based on a number of reported features, RPP could be a great plasticizer to address future environmental problems.}, } @article {pmid38485676, year = {2024}, author = {Nasrollahian, S and Pourmoshtagh, H and Sabour, S and Hadi, N and Azimi, T and Soleiman-Meigooni, S}, title = {Biofilm Formation in Mycobacterial Genus; Mechanism of Biofilm Formation and Anti-Mycobacterial Biofilm Agents.}, journal = {Current pharmaceutical biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.2174/0113892010277107240227054933}, pmid = {38485676}, issn = {1873-4316}, abstract = {Mycobacterium tuberculosis, Mycobacterium leprae, and non-tuberculous mycobacteria (NTM) are among the most significant human pathogens within the Mycobacterium genus. These pathogens can infect people who come into contact with biomaterials or have chronic illnesses. A characteristic pathogenic trait of mycobacteria is the development of biofilms, which involves several molecules, such as the GroEL1 chaperone, glycopeptidolipids, and shorter-chain mycolic acids. Bacterial behavior is influenced by nutrients, ions, and carbon sources, which also play a regulatory role in biofilm development. Compared to their planktonic phase, mycobacterial biofilms are more resilient to environmental stresses and disinfectants. Mycobacteria that produce biofilms have been found in several environmental studies, particularly in water systems. NTM can cause respiratory problems in individuals with underlying illnesses such as cystic fibrosis, bronchiectasis, and old tuberculosis scars. Mycobacteria that grow slowly, like those in the Mycobacterium avium complex (MAC), or rapidly, like Mycobacterium abscessus, can be pathogens. Infections related to biomaterials represent a significant category of biofilm-associated infections, with rapidly growing mycobacteria being the most frequently identified organisms. A biofilm produced by M. tuberculosis can contribute to caseous necrosis and cavity formation in lung tissue. Additionally, M. tuberculosis forms biofilms on clinical biomaterials. Biofilm formation is a major contributor to antimicrobial resistance, providing defense against drugs that would typically be effective against these bacteria in their planktonic state. The antibiotic resistance of biofilm-forming microbes may render therapy ineffective, necessitating the physical removal of biofilms to cure the infection. Recently, new approaches have been developed with potential anti-biofilm compounds to increase treatment effectiveness. Understanding biofilms is crucial for the appropriate treatment of various NTM diseases, and the recent discovery of M. tuberculosis biofilms has opened up a new field of study. This review focuses on the biofilm formation of the Mycobacterial genus, the mechanisms of biofilm formation, and anti-mycobacterial biofilm agents.}, } @article {pmid38484996, year = {2024}, author = {Mkpuma, VO and Moheimani, NR and Ennaceri, H}, title = {Biofilm cultivation of chlorella species. MUR 269 to treat anaerobic digestate food effluent (ADFE): Total ammonia nitrogen (TAN) concentrations effect.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141688}, doi = {10.1016/j.chemosphere.2024.141688}, pmid = {38484996}, issn = {1879-1298}, abstract = {Microalgal-based treatment of anaerobic digestate food effluent (ADFE) has been found to be efficient and effective. However, turbidity and high total ammonia nitrogen (TAN)) content of ADFE is a major setback, requiring significant dilution. Although the possibility of growing microalgae in a high-strength ADFE with minimal dilution has been demonstrated in suspension cultures, such effluents remain highly turbid and affect the light path in suspension cultures. Here, the feasibility of growing Chlorella sp. (MUR 269) in biofilm to treat ADFE with high TAN concentrations was investigated. Six different TAN concentrations in ADFE were evaluated for their effects on biofilm growth and nutrient removal by Chlorella sp. MUR 269 using the perfused biofilm technique. Biomass yields and productivities of this alga at various TAN concentrations (mg N NH3 L[-1]) were 55[a] (108 g m[-2] and 9.80 g m[-2] d[-1])>100[b] > 200[c] = 300[c] = 500[c] > 1000[d]. Growth was inhibited, resulting in a 28% reduction in yield of Chlorella biofilm when this alga was grown at 1000 mg N NH3 L[-1]. A survey of the photosynthetic parameters reveals evidence of stress occurring in the following sequence: 55 < 100<200 < 300<1000. A significant nutrient removal was observed across various TAN concentrations. The removal pattern also followed the concentration gradients except COD, where the highest removal occurred at 500 mg N NH3 L[-1]. Higher removal rates were seen at higher nutrient concentrations and declined gradually over time. In general, our results indicated that the perfused biofilm strategy is efficient, minimizes water consumption, offers easy biomass harvesting, and better exposure to light. Therefore, it can be suitable for treating turbid and concentrated effluent with minimal treatment to reduce the TAN concentration.}, } @article {pmid38484992, year = {2024}, author = {Chandra Sarker, D and Bal Krishna, KC and Maneesha, PG and Sathasivan, A}, title = {Effective chloramine management without "burn" in biofilm affected nitrifying tanks using a low dose of copper.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141709}, doi = {10.1016/j.chemosphere.2024.141709}, pmid = {38484992}, issn = {1879-1298}, abstract = {This paper highlights the potential to effectively inhibit nitrification and restore chloramine levels using a low copper concentration in a biofilm-affected (surface-to-volume ratio 16 m[-1]) continuous-flow laboratory-scale chloraminated system. High nitrite and low chloramine containing tanks are always recovered with chlorine "burn" by water utilities. The "burn" is not only costly and operationally complex, but also compromises the water quality, public health, and customer relations. A laboratory system comprising five reactors connected in series was operated. Each reactor simulated conditions typically encountered in full-scale systems. Low amount of copper (0.1-0.2 mg-Cu L[-1]) was dosed once per day into nitrified reactors. At any given time, only one reactor was dosed with copper. Not only inhibition of nitrification, chloramine decay associated with bulk water, biofilm and sediments also improved. However, the improvement was quicker and more significant when the influent to the reactor contained a high chloramine and a low nitrite concentration. Ammonia oxidising microbes exhibited resilience when exposed to low copper and chloramine concentrations for an extended period. Chloramine decay due to planktonic microbes and chemical reactions in bulk water decreased more rapidly than decay attributed to biofilm and sediments. The concept "biostable residual chlorine" explained how copper and chloramine can inhibit nitrification. Once nitrification was inhibited, the chloramine supplied from upstream effectively continued to suppress downstream nitrification, and this effect lasted more than 50 days even at 22 °C. The findings could be used to develop short-term copper dosing strategies and prevent negative impacts of nitrification and breakpoint chlorination.}, } @article {pmid38483493, year = {2024}, author = {Hanay, Ö and Aksoy, Y and Çelik, A and Yegin, M}, title = {Modifying gas transfer membranes with nanoscale zero-valent iron: effects on membrane material properties, treatment performance, and biofilm thickness.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {89}, number = {5}, pages = {1195-1210}, doi = {10.2166/wst.2024.062}, pmid = {38483493}, issn = {0273-1223}, abstract = {Excessive membrane biofilm growth on membrane fibers depends on various factors, with membrane properties playing a pivotal role in influencing microbial affinity for the membrane. To investigate the antibacterial impact of nano-sized zero-valent iron (nZVI) on membrane biofilm structure, pristine (polyvinylidene fluoride (PVDF)) only: HF-0 (PVDF:20/nZVI:0 w/w) and four gas transfer membranes (PVDF:nZVI at different concentrations: HF-1 (PVDF:20/nZVI:0.25 w/w), HF-2 (PVDF:20/nZVI:0.50 w/w), HF-3 (PVDF:20/nZVI:0.75 w/w), HF-4 (PVDF:20/nZVI:1.0 w/w)) were produced. These membranes were assessed for surface morphology, porosity, gas permeability, and biofilm thickness, which ultimately affect biochemical reaction rates in membrane biofilm reactors (MBfRs). Various MBfRs utilizing these gas transfer membranes were operated at different hydraulic retention times (HRTs) and oxygen pressures to assess chemical oxygen demand (COD) removal efficiency and nitrification performance. Incorporating nZVI into the PVDF polymer solution increased surface hydrophilicity and porosity but reduced Young's Modulus and oxygen diffusion coefficients. Confocal laser scanning microscopy (CLSM) analysis revealed an average biofilm thickness of 700 μm in HF-0, HF-1, and HF-3, with a 100 μm decrease in HF-2, even though Escherichia coli growth was observed in HF-3 fibers. Regardless of nZVI dosage, a significant decline in COD removal and nitrification rates occurred at low HRTs and gas pressures.}, } @article {pmid38483489, year = {2024}, author = {An, N and Ma, L and Lian, D and Wang, S}, title = {Effect of salinity on denitrification, membrane fouling and bacterial community in a fixed-bed biofilm membrane reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {89}, number = {5}, pages = {1124-1141}, doi = {10.2166/wst.2024.050}, pmid = {38483489}, issn = {0273-1223}, abstract = {In this study, a fixed-bed biofilm membrane bioreactor was used to assess denitrification and carbon removal performance, membrane fouling, composition, and the dynamics of microbial communities across 10 salinity levels. As salinity levels increased (from 0 to 30 g/L), the removal efficiency of total nitrogen and chemical oxygen demand decreased from 98 and 86% in Phase I to 25 and 45% in Phase X, respectively. Beyond a salinity level of 10 g/L, membrane fouling accelerated considerably. The analysis of fouling resistance distribution suggested that soluble microbial products (SMPs) were the primary cause of this phenomenon. The irregularity in microbial community succession reflected the varying adaptability of different bacteria to different salinity levels. The relative abundance of Sulfuritalea, Lentimircobium, Thauera, and Pseudomonas increased from 20.2 to 47.7% as the experiments progressed. Extracellular polymeric substances-related analysis suggested that Azospirillum plays a positive role in preserving the structural integrity of the biofilm carrier. The SMP-related analysis showed a positive correlation between Lentimircobium, Thauera, Pseudomonas, and the SMP content. These results suggested that these three bacterial genera significantly promoted the release of SMP under salt stress, which in turn led to severe membrane fouling.}, } @article {pmid38482364, year = {2024}, author = {Wanja, FK and Omwenga, EO and Ngugi, CW and Maina, JN and Kiiru, JN}, title = {Genotypic characterization of bacterial isolates causing urinary tract infections among adults at Kiambu Level 5 Hospital, Kenya: selected extended-spectrum β-lactamase genes and biofilm formation.}, journal = {Access microbiology}, volume = {6}, number = {2}, pages = {}, pmid = {38482364}, issn = {2516-8290}, abstract = {The menace of antimicrobial resistance affecting public health is rising globally. Many pathogenic bacteria use mechanisms such as mutations and biofilm formation, significantly reducing the efficacy of antimicrobial agents. In this cross-sectional study, we aimed to determine the prevalence of selected extended-spectrum β-lactamase (ESβL) genes and analyse the biofilm formation abilities of the isolated bacteria causing urinary tract infection among adult patients seeking Medicare at Kiambu Level 5 Hospital, Kenya. The double-disc synergy test was used for phenotypic identification of ESβL-producing isolates, while microtitre plate assays with some modifications were used for the biofilm formation test. Ten isolates were bioassayed for ESβL genes out of 57 bacterial isolates obtained from urine samples. This study found the bla TEM genes to be the most prevalent ESβL type [10/10 (100 %)], followed by blaOXA and blaSHV genes at 4/10 (40 %) and 3/10 (30 %), respectively. In addition, co-carriage of blaTEM and blaSHV was 50 % lower than that of blaTEM+bla OXA genes at 66.7 % among Escherichia coli isolates studied. Biofilm formation was positive in 36/57 (63.2 %) of the isolates tested, with most being Gram-negative [25/36 (69.4 %)]. Escherichia coli [15/36 (41.7 %)], Klebsiella species [7/36 (19.4 %)] and Staphylococcus aureus [7/36 (19.4 %)] were the dominant biofilm formers. However, there was no significant difference in biofilm formation among all tested isolates, with all isolates recording P-values >0.05. In light of these findings, biofilm formation potential coupled with antimicrobial resistance genes in urinary tract infection isolates may lead to difficult-to-treat infections.}, } @article {pmid38482344, year = {2024}, author = {Watson, F and Wilks, S and Chewins, J and Keevil, B}, title = {Efficiency and novelty of using environmental swabs for dry-surface biofilm recovery.}, journal = {Access microbiology}, volume = {6}, number = {2}, pages = {}, pmid = {38482344}, issn = {2516-8290}, abstract = {Studies on the epidemiology of dry-surface biofilms (DSBs) within healthcare settings have shown an almost universal distribution across frequently touched items. Despite a growing body of evidence for DSBs in hospitals, little attention has been paid to the recovery capacity of techniques used to detect these microbial communities. Biofilms are inherently difficult to remove from surfaces due to adhesive substances within their matrix and may act as sources of infection, but to what extent is largely unknown. In this study, we evaluate the recovery efficiencies of commonly used environmental swabs against DSBs containing 7.24 log10 Acinetobacter baumannii cm[-2], using a drip flow reactor and desiccation cycle. Biofilm presence was visually confirmed using episcopic differential interference contrast microscopy combined with epifluorescence and quantified using sonicated viable plate counts. The swab materials used comprised foam, viscose and cotton, all of which were pre-moistened using a buffer solution. The surfaces were vigorously swabbed by each material type and the resultant microbe populations for both swabs and remaining DSBs were quantified. Our results found foam-tipped swabs to be superior, detecting on average 30 % of the original DSB contamination; followed by viscose (6 %) and cotton (3 %). However, no distinct difference was revealed in the concentration of microbes remaining on the surface after swabbing for each swab type, suggesting there is variation in the capacity for each swab to release biofilm-associated micro-organisms. We conclude whilst environmental swabs do possess the ability to detect biofilms on dry surfaces, the reduced efficiencies are likely to cause an underestimation of the microbes present and should be considered during clinical application.}, } @article {pmid38481050, year = {2024}, author = {Nguyen, KCT and Truong, PH and Thi, HT and Ho, XT and Nguyen, PV}, title = {Prevalence, multidrug resistance, and biofilm formation of Vibrio parahaemolyticus isolated from fish mariculture environments in Cat Ba Island, Vietnam.}, journal = {Osong public health and research perspectives}, volume = {15}, number = {1}, pages = {56-67}, doi = {10.24171/j.phrp.2023.0181}, pmid = {38481050}, issn = {2210-9099}, abstract = {BACKGROUND: Vibrio parahaemolyticus is a major foodborne pathogen in aquatic animals and a threat to human health worldwide. This study investigated the prevalence, antimicrobial resistance, antimicrobial resistance genes (ARGs), and biofilm formation of V. parahaemolyticus strains isolated from fish mariculture environments in Cat Ba Island, Vietnam.

METHODS: In total, 150 rearing water samples were collected from 10 fish mariculture farms in winter and summer. A polymerase chain reaction assay was used to identify V. parahaemolyticus, its virulence factors, and ARGs. The antimicrobial resistance patterns and biofilm formation ability of V. parahaemolyticus strains were investigated using the disk diffusion test and a microtiter plate-based crystal violet method, respectively.

RESULTS: Thirty-seven V. parahaemolyticus isolates were recovered from 150 samples. The frequencies of the tdh and trh genes among V. parahaemolyticus isolates were 8.1% and 21.6%, respectively. More than 90% of isolates were susceptible to ceftazidime, cefotaxime, and chloramphenicol, but over 72% were resistant to ampicillin, tetracycline, and erythromycin. Furthermore, 67.57% of isolates exhibited multidrug resistance. The presence of ARGs related to gentamicin (aac(3)-IV), tetracycline (tetA) and ciprofloxacin (qnrA) in V. parahaemolyticus isolates was identified. Conversely, no ARGs related to ampicillin or erythromycin resistance were detected. Biofilm formation capacity was detected in significantly more multidrug-resistant isolates (64.9%) than non-multidrug-resistant isolates (18.9%).

CONCLUSION: Mariculture environments are a potential source of antibiotic-resistant V. parahaemolyticus and a hotspot for virulence genes and ARGs diffusing to aquatic environments. Thus, the prevention of antibiotic-resistant foodborne vibriosis in aquatic animals and humans requires continuous monitoring.}, } @article {pmid38480832, year = {2024}, author = {Mahdiani, H and Yazdani, F and Khoramipour, M and Valizadeh, V and Bakhshandeh, H and Dinarvand, R}, title = {Preparation and Physicochemical Characterization of Hyaluronic Acid-Lysine Nanogels Containing Serratiopeptidase to Control Biofilm Formation.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {6111}, pmid = {38480832}, issn = {2045-2322}, abstract = {Remarkable resistance of bacterial biofilms to high doses of antimicrobials and antibiotics is one of their main challenges. Encapsulation of proteolytic enzymes is one of the suggested strategies to tackle this problem. In this regard, the antibacterial and anti-biofilm activity of biocompatible hyaluronic acid- Lysine nanogels containing serratiopeptidase (SRP-loaded HA-Lys nanogel) was assessed against P. aeruginosa and S. aureus strains. SRP-loaded HA-Lys nanogel was prepared using dropping method and optimized by Box-Behnken experimental design. These formulations were studied for physical characterization, release profile, stability, bioactivity, and anti-biofilm effects. The particle size, polydispersity index (PDI), and surface charge were measured by Zetasizer Nano ZS. The average particle size and zeta potential of the optimum sample were 156 nm and -14.1 mV, respectively. SRP release showed an initial burst followed by sustained release and the highest release was around 77%. Enzyme biological activity data revealed the higher efficiency of free SRP compared to SRP-loaded HA-Lys nanogel. The time-kill assay showed that both forms of SRP-loaded HA-Lys nanogel and blank HA-Lys nanogel showed significant antimicrobial activity against examined bacteria in comparison to the free enzyme. The obtained results demonstrated improved anti-biofilm efficacy and down regulation of tested biofilm genes for both SRP-loaded HA-Lys nanogel 100% and blank HA-Lys nanogel 100% compared to SRP 100%.}, } @article {pmid38480540, year = {2024}, author = {Koul, K and Jawanda, IK and Soni, T and Singh, P and Sharma, D and Kumari, S}, title = {Quantum dots: a next generation approach for pathogenic microbial biofilm inhibition; mechanistic insights, existing challenges, and future potential.}, journal = {Archives of microbiology}, volume = {206}, number = {4}, pages = {158}, pmid = {38480540}, issn = {1432-072X}, abstract = {Quantum Dots (QDs) have emerged as versatile nanomaterials with origins spanning organic, inorganic, and natural sources, revolutionizing various biomedical applications, particularly in combating pathogenic biofilm formation. Biofilms, complex structures formed by microbial communities enveloped in exopolysaccharide matrices, pose formidable challenges to traditional antibiotics due to their high tolerance and resistance, exacerbating inefficacy issues in antibiotic treatments. QDs offer a promising solution, employing physical mechanisms like photothermal or photodynamic therapy to disrupt biofilms. Their efficacy is noteworthy, with lower susceptibility to resistance development and broad-spectrum action as compared to conventional antibiotic methods. The stability and durability of QDs ensure sustained biofilm activity, even in challenging environmental conditions. This comprehensive review delves into the synthesis, properties, and applications of Carbon Quantum Dots (CQDs), most widely used QDs, showcasing groundbreaking developments that position these nanomaterials at the forefront of cutting-edge research and innovation. These nanomaterials exhibit multifaceted mechanisms, disrupting cell walls and membranes, generating reactive oxygen species (ROS), and binding to nucleic materials, effectively inhibiting microbial proliferation. This opens transformative possibilities for healthcare interventions by providing insights into biofilm dynamics. However, challenges in size control necessitate ongoing research to refine fabrication techniques, ensure defect-free surfaces, and optimize biological activity. QDs emerge as microscopic yet potent tools, promising to contribute to a brighter future where quantum wonders shape innovative solutions to persistently challenging issues posed by pathogenic biofilms. Henceforth, this review aims to explore QDs as potential agents for inhibiting pathogenic microbial biofilms, elucidating the underlying mechanisms, addressing the current challenges, and highlighting their promising future potential.}, } @article {pmid38478426, year = {2024}, author = {Higazy, D and Pham, AD and van Hasselt, JGC and Høiby, N and Jelsbak, L and Moser, C and Ciofu, O}, title = {In vivo evolution of antimicrobial resistance in a biofilm model of Pseudomonas aeruginosa lung infection.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1093/ismejo/wrae036}, pmid = {38478426}, issn = {1751-7370}, abstract = {The evolution of antimicrobial resistance (AMR) in biofilms has been repeatedly studied by experimental evolution in vitro, but rarely in vivo. The complex microenvironment at the infection site imposes selective pressures on the bacterial biofilms, potentially influencing the development of AMR. We report here the development of AMR in an in vivo mouse model of Pseudomonas aeruginosa biofilm lung infection. P. aeruginosa embedded in seaweed alginate beads underwent four successive lung infection passages with or without ciprofloxacin exposure (CIP). The development of CIP resistance was assessed at each passage by population analysis of the bacterial populations recovered from the lungs of CIP-treated and control mice, with subsequent whole genome sequencing of selected isolates. As inflammation plays a crucial role in shaping the microenvironment at the infection site, its impact was explored through the measurement of cytokine levels in the lung homogenate. A rapid development of AMR was observed starting from the second passage in the CIP-treated mice. Genetic analysis revealed mutations in nfxB, efflux pumps (mexZ), and two-component systems (parS) contribution to CIP resistance. The control group isolates exhibited mutations in the dipA gene, likely associated with biofilm dispersion. In the initial two passages, the CIP-treated group exhibited an elevated inflammatory response compared to the control group. This increase may potentially contribute to the release of mutagenic reactive oxygen species and the development of AMR. In conclusion, this study illustrates the complex relationship between infection, antibiotic treatment, and immune response.}, } @article {pmid38477452, year = {2024}, author = {Luo, Z and Lu, R and Shi, T and Ruan, Z and Wang, W and Guo, Z and Zhan, Z and Ma, Y and Lian, X and Ding, C and Chen, Y}, title = {Enhanced Bacterial Cuproptosis-Like Death via Reversal of Hypoxia Microenvironment for Biofilm Infection Treatment.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2308850}, doi = {10.1002/advs.202308850}, pmid = {38477452}, issn = {2198-3844}, support = {81974340//National Natural Science Foundation of China/ ; 82172455//National Natural Science Foundation of China/ ; YG2021ZD22//Interdisciplinary Program of Shanghai Jiao Tong University/ ; SHDC12021117//Shanghai Shenkang Hospital Development Center Clinical Innovation Project/ ; 2023M732289//China Postdoctoral Science Foundation/ ; DWLL-2023-0527//Animal Welfare Ethics Committee of Shanghai Sixth People's Hospital/ ; 22S31900200//Shanghai Science and Technology Innovation Action Plan Program/ ; }, abstract = {A recently emerging cell death pathway, known as copper-induced cell death, has demonstrated significant potential for treating infections. Existing research suggests that cells utilizing aerobic respiration, as opposed to those reliant on glycolysis, exhibit greater sensitivity to copper-induced death. Herein, a MnO2 -loaded copper metal-organic frameworks platform is developed denoted as MCM, to enhance bacterial cuproptosis-like death via the remodeling of bacterial respiratory metabolism. The reversal of hypoxic microenvironments induced a cascade of responses, encompassing the reactivation of suppressed immune responses and the promotion of osteogenesis and angiogenesis. Initially, MCM catalyzed O2 production, alleviating hypoxia within the biofilm and inducing a transition in bacterial respiration mode from glycolysis to aerobic respiration. Subsequently, the sensitized bacteria, characterized by enhanced tricarboxylic acid cycle activity, underwent cuproptosis-like death owing to increased copper concentrations and aggregated intracellular dihydrolipoamide S-acetyltransferase (DLAT). The disruption of hypoxia also stimulated suppressed dendritic cells and macrophages, thereby strengthening their antimicrobial activity through chemotaxis and phagocytosis. Moreover, the nutritional effects of copper elements, coupled with hypoxia alleviation, synergistically facilitated the regeneration of bones and blood vessels. Overall, reshaping the infection microenvironment to enhance cuproptosis-like cell death presents a promising avenue for eradicating biofilms.}, } @article {pmid38477236, year = {2024}, author = {Shi, Y and Wen, T and Zhao, F and Hu, J}, title = {Bacteriostasis of nisin against planktonic and biofilm bacteria: Its mechanism and application.}, journal = {Journal of food science}, volume = {}, number = {}, pages = {}, doi = {10.1111/1750-3841.17001}, pmid = {38477236}, issn = {1750-3841}, support = {31801651//National Natural Science Foundation of China/ ; JJKH20241308CY//The scientific research project of the Education Department of Jilin Province/ ; }, abstract = {Food safety incidents caused by bacterial contamination have always been one of the public safety issues of social concern. Planktonic cells, viable but non-culturable (VBNC) cells, and biofilm cells of bacteria can coexist in food or food processing, posing more serious challenges to public health and safety by increasing bacterial survival and difficulty in detection. As a non-toxic, no side effect, and highly effective bacteriostatic substance, nisin has received wide attention from researchers. In this review, we summarized the species and biosynthesis of nisin, the effects of nisin alone or in combination with other treatments on planktonic and biofilm cells, and its applications in the fields of food, feed, and medicine by consulting numerous studies. Meanwhile, the mechanism of nisin on planktonic and biofilm cells was proposed based on existing researches. Nisin not only has antibacterial activity against most G[+] bacteria but also exhibits a bacteriostatic effect on G[-] bacteria when combined with other antibacterial treatments. In addition to planktonic cells, nisin also has significant effects on bacterial cells in biofilms by changing the thickness, density, and composition of biofilms. Based on the three action processes of nisin on biofilms, we summarized the changes of bacteria in biofilms, including the causes of bacterial death and the formation of the VBNC state. We consider that research on the relationship between nisin and VBNC state should be strengthened.}, } @article {pmid38475926, year = {2024}, author = {Suarez, C and Rosenqvist, T and Dimitrova, I and Sedlacek, CJ and Modin, O and Paul, CJ and Hermansson, M and Persson, F}, title = {Biofilm colonization and succession in a full-scale partial nitritation-anammox moving bed biofilm reactor.}, journal = {Microbiome}, volume = {12}, number = {1}, pages = {51}, pmid = {38475926}, issn = {2049-2618}, support = {2018-01423//Svenska Forskningsrådet Formas/ ; 2019-00432//Svenska Forskningsrådet Formas/ ; 2019-00432//Svenska Forskningsrådet Formas/ ; 2018-01423//Svenska Forskningsrådet Formas/ ; 2020-01905//Svenska Forskningsrådet Formas/ ; ZK74//Austrian Science Fund/ ; }, abstract = {BACKGROUND: Partial nitritation-anammox (PNA) is a biological nitrogen removal process commonly used in wastewater treatment plants for the treatment of warm and nitrogen-rich sludge liquor from anaerobic digestion, often referred to as sidestream wastewater. In these systems, biofilms are frequently used to retain biomass with aerobic ammonia-oxidizing bacteria (AOB) and anammox bacteria, which together convert ammonium to nitrogen gas. Little is known about how these biofilm communities develop, and whether knowledge about the assembly of biofilms in natural communities can be applied to PNA biofilms.

RESULTS: We followed the start-up of a full-scale PNA moving bed biofilm reactor for 175 days using shotgun metagenomics. Environmental filtering likely restricted initial biofilm colonization, resulting in low phylogenetic diversity, with the initial microbial community comprised mainly of Proteobacteria. Facilitative priority effects allowed further biofilm colonization, with the growth of initial aerobic colonizers promoting the arrival and growth of anaerobic taxa like methanogens and anammox bacteria. Among the early colonizers were known 'oligotrophic' ammonia oxidizers including comammox Nitrospira and Nitrosomonas cluster 6a AOB. Increasing the nitrogen load in the bioreactor allowed colonization by 'copiotrophic' Nitrosomonas cluster 7 AOB and resulted in the exclusion of the initial ammonia- and nitrite oxidizers.

CONCLUSIONS: We show that complex dynamic processes occur in PNA microbial communities before a stable bioreactor process is achieved. The results of this study not only contribute to our knowledge about biofilm assembly and PNA bioreactor start-up but could also help guide strategies for the successful implementation of PNA bioreactors. Video Abstract.}, } @article {pmid38475877, year = {2024}, author = {Lou, Z and Dong, J and Tao, H and Tan, Y and Wang, H}, title = {Regulation and mechanism of organic selenium on quorum sensing, biofilm, and antioxidant effects of Lactobacillus paracasei.}, journal = {Cell biochemistry and function}, volume = {42}, number = {2}, pages = {e3975}, doi = {10.1002/cbf.3975}, pmid = {38475877}, issn = {1099-0844}, support = {JUFSTR20180204//National First-class Discipline Program of Food Science and Technology/ ; }, abstract = {Different organic compounds can have varying degrees of impact on the activity of Lactobacillus paracasei. The study focused on the impact and action mechanism of different organic selenium products on the bioactivity of two strains of L. paracasei. The growth, antioxidant activity, extracellular polysaccharide secretion, quorum sensing (QS), and biofilm formation of the strains before and after the addition of organic selenium crude products and three organic selenium standard were evaluated. The results showed that the addition of crude organic selenium promoted the various activities of the strain. l-selenocysteine had the strongest regulatory effect, with maximum GIM1.80 biofilm formation when it reached a critical concentration of 0.4 μg/mL; l-selenomethionine resulted in the highest activity of the signal molecule Auto inducer-2 of GDMCC1.155, when it reached a critical concentration of 0.4 μg/mL. The results of scanning electron microscopy demonstrated that the addition of organic selenium effectively improved the morphological structure of the two bacterial cells. Molecular docking revealed that the mechanism by which organic selenium regulates QS in Lactobacillus was achieved by binding two crucial receptor proteins (histidine protein kinase HKP and periplasmic binding protein LuxP) from specific sites. Furthermore, organic selenium products have a beneficial regulatory effect on the biological activity of L. paracasei. Overall, these findings provide a new alternative (organic selenium) for regulating the viability and beneficial activity of L. paracasei.}, } @article {pmid38474323, year = {2024}, author = {Shi, L and Lin, W and Cai, Y and Chen, F and Zhang, Q and Liang, D and Xiu, Y and Lin, S and He, B}, title = {Oxidative Stress-Mediated Repression of Virulence Gene Transcription and Biofilm Formation as Antibacterial Action of Cinnamomum burmannii Essential Oil on Staphylococcus aureus.}, journal = {International journal of molecular sciences}, volume = {25}, number = {5}, pages = {}, doi = {10.3390/ijms25053078}, pmid = {38474323}, issn = {1422-0067}, abstract = {This work aimed to identify the chemical compounds of Cinnamomum burmannii leaf essential oil (CBLEO) and to unravel the antibacterial mechanism of CBLEO at the molecular level for developing antimicrobials. CBLEO had 37 volatile compounds with abundant borneol (28.40%) and showed good potential to control foodborne pathogens, of which Staphylococcus aureus had the greatest inhibition zone diameter (28.72 mm) with the lowest values of minimum inhibitory concentration (1.0 μg/mL) and bactericidal concentration (2.0 μg/mL). To unravel the antibacterial action of CBLEO on S. aureus, a dynamic exploration of antibacterial growth, material leakage, ROS formation, protein oxidation, cell morphology, and interaction with genome DNA was conducted on S. aureus exposed to CBLEO at different doses (1/2-2×MIC) and times (0-24 h), indicating that CBLEO acts as an inducer for ROS production and the oxidative stress of S. aureus. To highlight the antibacterial action of CBLEO on S. aureus at the molecular level, we performed a comparative association of ROS accumulation with some key virulence-related gene (sigB/agrA/sarA/icaA/cidA/rsbU) transcription, protease production, and biofilm formation in S. aureus subjected to CBLEO at different levels and times, revealing that CBLEO-induced oxidative stress caused transcript suppression of virulence regulators (RsbU and SigB) and its targeted genes, causing a protease level increase destined for the biofilm formation and growth inhibition of S. aureus, which may be a key bactericidal action. Our findings provide valuable information for studying the antibacterial mechanism of essential oil against pathogens.}, } @article {pmid38474038, year = {2024}, author = {Thamizhchelvan, AM and Masoud, AR and Su, S and Lu, Y and Peng, H and Kobayashi, Y and Wang, Y and Archer, NK and Hong, S}, title = {Bactericidal Efficacy of the Combination of Maresin-like Proresolving Mediators and Carbenicillin Action on Biofilm-Forming Burn Trauma Infection-Related Bacteria.}, journal = {International journal of molecular sciences}, volume = {25}, number = {5}, pages = {}, doi = {10.3390/ijms25052792}, pmid = {38474038}, issn = {1422-0067}, support = {1R01GM136874(to SH)//National Institute of Health/ ; 1R21AG068756 (to SH)//National Institute of Health/ ; 1R21AG066119 (to SH)//National Institute of Health/ ; research enhancement fund (to SH)//LSU Health-New Orleans/ ; JP15H05904, JP15H05898, JP15H05897, JP15H04648 (to K. Y.)//by KAKENHI/ ; (to K. Y.).//the Kobayashi International Scholarship/ ; }, abstract = {Biofilm-associated bacterial infections are the major reason for treatment failure in many diseases including burn trauma infections. Uncontrolled inflammation induced by bacteria leads to materiality, tissue damage, and chronic diseases. Specialized proresolving mediators (SPMs), including maresin-like lipid mediators (MarLs), are enzymatically biosynthesized from omega-3 essential long-chain polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), by macrophages and other leukocytes. SPMs exhibit strong inflammation-resolving activities, especially inflammation provoked by bacterial infection. In this study, we explored the potential direct inhibitory activities of three MarLs on Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria in their biofilms that are leading bacteria in burn trauma-related infections. We also examined the effects of MarLs on the bactericidal activities of a typical broad-spectrum antibiotic, carbenicillin (carb), on these bacteria in their preformed biofilms. The results revealed that MarLs combined with carbenicillin can inhibit the survival of Gram-positive and Gram-negative bacteria in their biofilms although MarLs alone did not exhibit bactericidal activity. Thus, our findings suggest that the combination of MarLs and carbenicillin can lower the antibiotic requirements to kill the bacteria in preformed biofilms.}, } @article {pmid38474027, year = {2024}, author = {Menotti, F and Scutera, S and Maniscalco, E and Coppola, B and Bondi, A and Costa, C and Longo, F and Mandras, N and Pagano, C and Cavallo, L and Banche, G and Malandrino, M and Palmero, P and Allizond, V}, title = {Is Silver Addition to Scaffolds Based on Polycaprolactone Blended with Calcium Phosphates Able to Inhibit Candida albicans and Candida auris Adhesion and Biofilm Formation?.}, journal = {International journal of molecular sciences}, volume = {25}, number = {5}, pages = {}, doi = {10.3390/ijms25052784}, pmid = {38474027}, issn = {1422-0067}, support = {RF = 2019.0588//Fondazione CRT/ ; }, abstract = {Candida spp. periprosthetic joint infections are rare but difficult-to-treat events, with a slow onset, unspecific symptoms or signs, and a significant relapse risk. Treatment with antifungals meets with little success, whereas prosthesis removal improves the outcome. In fact, Candida spp. adhere to orthopedic devices and grow forming biofilms that contribute to the persistence of this infection and relapse, and there is insufficient evidence that the use of antifungals has additional benefits for anti-biofilm activity. To date, studies on the direct antifungal activity of silver against Candida spp. are still scanty. Additionally, polycaprolactone (PCL), either pure or blended with calcium phosphate, could be a good candidate for the design of 3D scaffolds as engineered bone graft substitutes. Thus, the present research aimed to assess the antifungal and anti-biofilm activity of PCL-based constructs by the addition of antimicrobials, for instance, silver, against C. albicans and C. auris. The appearance of an inhibition halo around silver-functionalized PCL scaffolds for both C. albicans and C. auris was revealed, and a significant decrease in both adherent and planktonic yeasts further demonstrated the release of Ag[+] from the 3D constructs. Due to the combined antifungal, osteoproliferative, and biodegradable properties, PCL-based 3D scaffolds enriched with silver showed good potential for bone tissue engineering and offer a promising strategy as an ideal anti-adhesive and anti-biofilm tool for the reduction in prosthetic joints of infections caused by Candida spp. by using antimicrobial molecule-targeted delivery.}, } @article {pmid38473902, year = {2024}, author = {Buzalewicz, I and Kaczorowska, A and Fijałkowski, W and Pietrowska, A and Matczuk, AK and Podbielska, H and Wieliczko, A and Witkiewicz, W and Jędruchniewicz, N}, title = {Quantifying the Dynamics of Bacterial Biofilm Formation on the Surface of Soft Contact Lens Materials Using Digital Holographic Tomography to Advance Biofilm Research.}, journal = {International journal of molecular sciences}, volume = {25}, number = {5}, pages = {}, doi = {10.3390/ijms25052653}, pmid = {38473902}, issn = {1422-0067}, support = {POIR.04.01.01-00-0016/19-00//National Center for Research and Development/ ; 2021/41/B/ST7/04002//National Center of Science/ ; }, abstract = {The increase in bacterial resistance to antibiotics in recent years demands innovative strategies for the detection and combating of biofilms, which are notoriously resilient. Biofilms, particularly those on contact lenses, can lead to biofilm-related infections (e.g., conjunctivitis and keratitis), posing a significant risk to patients. Non-destructive and non-contact sensing techniques are essential in addressing this threat. Digital holographic tomography emerges as a promising solution. This allows for the 3D reconstruction of the refractive index distribution in biological samples, enabling label-free visualization and the quantitative analysis of biofilms. This tool provides insight into the dynamics of biofilm formation and maturation on the surface of transparent materials. Applying digital holographic tomography for biofilm examination has the potential to advance our ability to combat the antibiotic bacterial resistance crisis. A recent study focused on characterizing biofilm formation and maturation on six soft contact lens materials (three silicone hydrogels, three hydrogels), with a particular emphasis on Staphylococcus epidermis and Pseudomonas aeruginosa, both common culprits in ocular infections. The results revealed species- and time-dependent variations in the refractive indexes and volumes of biofilms, shedding light on cell dynamics, cell death, and contact lens material-related factors. The use of digital holographic tomography enables the quantitative analysis of biofilm dynamics, providing us with a better understanding and characterization of bacterial biofilms.}, } @article {pmid38473900, year = {2024}, author = {Juszczuk-Kubiak, E}, title = {Molecular Aspects of the Functioning of Pathogenic Bacteria Biofilm Based on Quorum Sensing (QS) Signal-Response System and Innovative Non-Antibiotic Strategies for Their Elimination.}, journal = {International journal of molecular sciences}, volume = {25}, number = {5}, pages = {}, doi = {10.3390/ijms25052655}, pmid = {38473900}, issn = {1422-0067}, abstract = {One of the key mechanisms enabling bacterial cells to create biofilms and regulate crucial life functions in a global and highly synchronized way is a bacterial communication system called quorum sensing (QS). QS is a bacterial cell-to-cell communication process that depends on the bacterial population density and is mediated by small signalling molecules called autoinducers (AIs). In bacteria, QS controls the biofilm formation through the global regulation of gene expression involved in the extracellular polymeric matrix (EPS) synthesis, virulence factor production, stress tolerance and metabolic adaptation. Forming biofilm is one of the crucial mechanisms of bacterial antimicrobial resistance (AMR). A common feature of human pathogens is the ability to form biofilm, which poses a serious medical issue due to their high susceptibility to traditional antibiotics. Because QS is associated with virulence and biofilm formation, there is a belief that inhibition of QS activity called quorum quenching (QQ) may provide alternative therapeutic methods for treating microbial infections. This review summarises recent progress in biofilm research, focusing on the mechanisms by which biofilms, especially those formed by pathogenic bacteria, become resistant to antibiotic treatment. Subsequently, a potential alternative approach to QS inhibition highlighting innovative non-antibiotic strategies to control AMR and biofilm formation of pathogenic bacteria has been discussed.}, } @article {pmid38473018, year = {2024}, author = {Giedraitiene, A and Tatarunas, V and Kaminskaite, K and Meskauskaite, U and Boieva, S and Ajima, Y and Ciapiene, I and Veikutiene, A and Zvikas, V and Kupstyte-Kristapone, N and Jakstas, V and Luksiene, D and Tamosiunas, A and Lesauskaite, V}, title = {Enterobacterales Biofilm-Specific Genes and Antimicrobial and Anti-Inflammatory Biomarkers in the Blood of Patients with Ischemic Heart Disease.}, journal = {Diagnostics (Basel, Switzerland)}, volume = {14}, number = {5}, pages = {}, doi = {10.3390/diagnostics14050546}, pmid = {38473018}, issn = {2075-4418}, abstract = {BACKGROUND: Ischemic heart disease (IHD) is the most prevalent type of cardiovascular disease. The main cause of IHD is atherosclerosis, which is a multifactorial inflammatory disease of blood vessels. Studies show that bacteria might have a significant impact on the pathogenesis of atherosclerosis and plaque rupture. This study aimed to evaluate the complexity of interactions between bacteria and the human body concerning metabolites and bacterial genes in patients with ischemic heart disease.

METHODS: Bacterial 16S rDNA and wcaF, papC, and sdhC genes were detected in whole blood using a real-time PCR methodology. An enzyme-linked immunosorbent assay was used to measure the concentration of the LL-37 protein. An analysis of ARA in blood plasma was performed.

RESULTS: Bacterial 16S rDNA was detected in 31% of the study patients, and the genes wcaF and sdhC in 20%. Enterobacterales genes were detected more frequently in patients younger than 65 years than in patients aged 65 years and older (p = 0.018) and in patients with type 2 diabetes (p = 0.048). Concentrations of the human antimicrobial peptide LL-37 and 12S-HETE concentrations were determined to be higher if patients had 16S rDNA and biofilm-specific genes.

CONCLUSIONS: The results of this study enhance the understanding that Enterobacterales bacteria may participate in the pathogenesis of atherosclerosis and IHD. Bacterial DNA and host metabolites in higher concentrations appear to be detected.}, } @article {pmid38472751, year = {2024}, author = {Sun, Y and Shuai, W and Nie, L and Li, X and Jiang, L}, title = {Investigating the Role of OrbF in Biofilm Biosynthesis and Regulation of Biofilm-Associated Genes in Bacillus cereus BC1.}, journal = {Foods (Basel, Switzerland)}, volume = {13}, number = {5}, pages = {}, doi = {10.3390/foods13050638}, pmid = {38472751}, issn = {2304-8158}, support = {2023YFD2100500//National Key Research and Development Program of China/ ; U2106228//National Natural Science Foundation of China/ ; 32300059//National Natural Science Foundation of China/ ; XTC2205//the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture/ ; BK20230314//Natural Science Foundation of Jiangsu Province/ ; 22KJB550008//Natural Science Foundation of the Jiangsu Higher Education Institutions of China/ ; 2022YOO068//Scientific Research Start-up Fund for Introduced Talents of Anhui Polytechnic University/ ; }, abstract = {Bacillus cereus (B. cereus), a prevalent foodborne pathogen, constitutes a substantial risk to food safety due to its pronounced resilience under adverse environmental conditions such as elevated temperatures and ultraviolet radiation. This resilience can be attributed to its capacity for biofilm synthesis and sustained high viability. Our research aimed to elucidate the mechanisms governing biofilm biosynthesis in B. cereus. To this end, we constructed a 5088-mutant library of the B. cereus strain BC1 utilizing the transposon TnYLB-1. Systematic screening of this library yielded mutants exhibiting diminished biofilm formation capabilities. Twenty-four genes associated with the biofilm synthesis were identified by reverse PCR in these mutants, notably revealing a significant reduction in biofilm synthesis upon disruption of the orbF gene in B. cereus BC1. Comparative analysis between the wild type and orbF-deficient BC1 strains (BC1ΔorbF) indicated a marked downregulation (decreased by 11.7% to 96.7%) in the expression of genes implicated in biofilm formation, flagellar assembly, and bacterial chemotaxis in the BC1ΔorbF. Electrophoretic mobility shift assay (EMSA) further corroborated the role of OrbF, demonstrating its binding to the promoter region of the biofilm gene cluster, subsequently leading to the suppression of transcriptional activity of biofilm-associated genes in B. cereus BC1. Our findings underscore the pivotal role of orbF in biofilm biosynthesis in B. cereus, highlighting its potential as a target for strategies aimed at mitigating biofilm formation in this pathogen.}, } @article {pmid38471695, year = {2024}, author = {Al-Sawarees, DK and Darwish, RM and Abu-Zurayk, R and Masri, MA}, title = {Assessing Silver Nanoparticle and Antimicrobial Combinations for Antibacterial Activity and Biofilm Prevention on Surgical Sutures.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxae063}, pmid = {38471695}, issn = {1365-2672}, abstract = {AIMS: To evaluate the effect of silver nanoparticles alone and in combination with Triclosan, and trans-cinnamaldehyde against S.aureus and E.coli biofilms on sutures to improve patients' outcomes.

METHODS AND RESULTS: Silver nanoparticles were prepared by chemical method and characterized by UV-visible spectrophotometer and dynamic light scattering. The minimum inhibitory concentration was assessed by the Microdilution assay. The antibiofilm activity was determined using crystal violet assay. A checkerboard assay using the fractional inhibitory concentration index and time-kill curve was used to investigate the synergistic effect of silver nanoparticle combinations. The hemolytic activity was determined using Erythrocyte Hemolytic Assay. Our results revealed that silver nanoparticles, Triclosan, and trans-cinnamaldehyde inhibited S.aureus and E.coli biofilms. Silver nanoparticles with trans-cinnamaldehyde showed a synergistic effect (FICI values 0.35 and 0.45 against S.aureus and E.coli biofilms, respectively), and silver nanoparticles with Triclosan showed complete inhibition of S.aureus biofilm. The hemolytic activity was < 2.50% for the combinations.

This study showed that combinations of trans-cinnamaldehyde and Triclosan with silver nanoparticles enhanced surgical suture performance and thus have a promising application in the prevention of surgical site infections.}, } @article {pmid38470268, year = {2024}, author = {Alreja, AB and Appel, AE and Zhu, JC and Riley, SP and Gonzalez-Juarbe, N and Nelson, DC}, title = {SP-CHAP, an endolysin with enhanced activity against biofilm pneumococci and nasopharyngeal colonization.}, journal = {mBio}, volume = {}, number = {}, pages = {e0006924}, doi = {10.1128/mbio.00069-24}, pmid = {38470268}, issn = {2150-7511}, abstract = {UNLABELLED: Streptococcus pneumoniae (Spn), a Gram-positive bacterium, is responsible for causing a wide variety of invasive infections. The emergence of multi-drug antibiotic resistance has prompted the search for antimicrobial alternatives. Phage-derived peptidoglycan hydrolases, known as endolysins, are an attractive alternative. In this study, an endolysin active against Spn, designated SP-CHAP, was cloned, produced, purified, biochemically characterized, and evaluated for its antimicrobial properties. Cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domains are widely represented in bacteriophage endolysins but have never previously been reported for pneumococcal endolysins. Here, we characterize the first pneumococcal endolysin with a CHAP catalytic domain. SP-CHAP was antimicrobial against all Spn serovars tested, including capsular and capsule-free pneumococci, and it was found to be more active than the most widely studied pneumococcal endolysin, Cpl-1, while not affecting various oral or nasal commensal organisms tested. SP-CHAP was also effective in eradicating Spn biofilms at concentrations as low as 1.56 µg/mL. In addition, a Spn mouse nasopharyngeal colonization model was employed, which showed that SP-CHAP caused a significant reduction in Spn colony-forming units, even more than Cpl-1. These results indicate that SP-CHAP may represent a promising alternative to combating Spn infections.

IMPORTANCE: Considering the high rates of pneumococcal resistance reported for several antibiotics, alternatives are urgently needed. In the present study, we report a Streptococcus pneumoniae-targeting endolysin with even greater activity than Cpl-1, the most characterized pneumococcal endolysin to date. We have employed a combination of biochemical and microbiological assays to assess the stability and lytic potential of SP-CHAP and demonstrate its efficacy on pneumococcal biofilms in vitro and in an in vivo mouse model of colonization. Our findings highlight the therapeutic potential of SP-CHAP as an antibiotic alternative to treat Streptococcus pneumoniae infections.}, } @article {pmid38468739, year = {2024}, author = {Modgil, V and Kaur, H and Mohan, B and Taneja, N}, title = {Association of Putative Virulence Genes with HEp-2 Cell Adherence and Biofilm Production in Enteroaggregative E. coli Strains Isolated from Acute Diarrheal and Healthy Children, India.}, journal = {Indian journal of microbiology}, volume = {64}, number = {1}, pages = {186-197}, pmid = {38468739}, issn = {0046-8991}, abstract = {Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhea in developed and industrialized countries in children. EAEC colonizes the human intestine and this ability to form colonies and biofilm is an important step in pathogenesis. Here, we investigated the relationship between known or putative 22 EAEC virulence genes and biofilm formation in isolates derived from acute diarrhea and healthy children and their aggregative adherence (AA) pattern with Hep-2 cell lines. A total of 138 EAEC isolates were recovered from 1210 stool samples from children (age < 10 years) suffering from acute diarrhea and 33 EAEC strains isolated from 550 healthy children (control group) of different Anganwadi centers in Chandigarh region were included. Polymerase chain reaction using the primer pair pCVD432 identified E. coli isolates as EAEC. A total of 22 virulence-related genes have been identified using M-PCR chain reactions. The crystal violet method was used for the quantitative biofilm assay. Aggregative adherence assay was also studied using HEp-2 cell lines. Of 138 EAEC isolates from the acute diarrheal group, 121 (87.6%) EAEC isolates produced biofilm. In our findings, typical EAEC (62%) isolates were strong biofilm producers (37.5%) in the diarrheal group. Among adhesive variants, agg4A (39.6%) and aggA (21.6%) were the most common and were statistically significant (p = 0.01 and p = 0.03 respectively). We reported that the aggR gene along with the typical AA pattern was present in 71.4% of the EAEC strains in the diarrheal group, whereas it was present in 44% of the control group. Other aggR non-dependent genes like ORF3 and eilA may also lead to biofilm formation. In conclusion, there is significant heterogeneity in putative virulence genes of EAEC isolates from children and biofilm formation is associated with the combination of many genes.}, } @article {pmid38467263, year = {2024}, author = {Cao, M and Su, J and Zhang, L and Ali, A and Wang, Z and Wang, Y and Bai, Y}, title = {Loofah sponge crosslinked polyethyleneimine loaded with biochar biofilm reactor for ecological remediation of oligotrophic water: Mechanism, performance, and functional characterization.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130567}, doi = {10.1016/j.biortech.2024.130567}, pmid = {38467263}, issn = {1873-2976}, abstract = {The removal of complex pollutants from oligotrophic water is an important challenge for researchers. In this study, the HCl-modified loofah sponge crosslinked polyethyleneimine loaded with biochar (LS/PEI@biochar) biofilm reactor was adapted to achieve efficient removal of complex pollutants in oligotrophic water. On the 35 d, the average removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH4[+]-N), calcium (Ca[2+]), and phosphate (PO4[3-]-P) in water was 51, 95, 81, and 77 %, respectively. Additionally, it effectively used a low molecular weight carbon source. Scanning electron microscopy (SEM) results showed that the LS/PEI@biochar biocarrier had superior biofilm suspension performance. Meanwhile, analysis of the biocrystals confirmed Ca[2+] and PO4[3-] removal through the generation of CaCO3 (calcite and vaterite) and Ca5(PO4)3OH. This study demonstrated that the system has great efficiency and application prospect in treating oligotrophic water on the laboratory scale, and will be further validated for practical application on large-scale oligotrophic water.}, } @article {pmid38466321, year = {2024}, author = {Jou-Claus, S and Rodríguez-Escales, P and Martínez-Landa, L and Diaz-Cruz, MS and Carrera, J and Sunyer-Caldú, A and Quintana, G and Valhondo, C}, title = {Assessing the Fate of Benzophenone-Type UV Filters and Transformation Products during Soil Aquifer Treatment: The Biofilm Compartment as Bioaccumulator and Biodegrader in Porous Media.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c08465}, pmid = {38466321}, issn = {1520-5851}, abstract = {The fate of selected UV filters (UVFs) was investigated in two soil aquifer treatment (SAT) systems, one supplemented with a reactive barrier containing clay and vegetable compost and the other as a traditional SAT reference system. We monitored benzophenone-3 (BP-3) and its transformation products (TPs), including benzophenone-1 (BP-1), 4,4'-dihydroxybenzophenone (4DHB), 4-hydroxybenzophenone (4HB), and 2,2'-dihydroxy-4-methoxybenzophenone (DHMB), along with benzophenone-4 (BP-4) and avobenzone (AVO) in all involved compartments (water, aquifer sediments, and biofilm). The reactive barrier, which enhances biochemical activity and biofilm development, improved the removal of all detected UVFs in water samples. Among monitored UVFs, only 4HB, BP-4, and AVO were detected in sediment and biofilm samples. But the overall retained amounts were several orders of magnitude larger than those dissolved. These amounts were quantitatively reproduced with a specifically developed simple analytical model that consists of a mobile compartment and an immobile compartment. Retention and degradation are restricted to the immobile water compartment, where biofilm absorption was simulated with well-known compound-specific Kow values. The fact that the model reproduced observations, including metabolites detected in the biofilm but not in the (mobile) water samples, supports its validity. The results imply that accumulation ensures significant biodegradation even if the degradation rates are very low and suggest that our experimental findings for UVFs and TPs can be extended to other hydrophobic compounds. Biofilms act as accumulators and biodegraders of hydrophobic compounds.}, } @article {pmid38465230, year = {2024}, author = {Li, L and Gao, X and Li, M and Liu, Y and Ma, J and Wang, X and Yu, Z and Cheng, W and Zhang, W and Sun, H and Song, X and Wang, Z}, title = {Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies.}, journal = {Frontiers in cellular and infection microbiology}, volume = {14}, number = {}, pages = {1324895}, pmid = {38465230}, issn = {2235-2988}, mesh = {Humans ; *Klebsiella pneumoniae/genetics ; *Klebsiella Infections/drug therapy/microbiology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Drug Resistance, Microbial ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.}, } @article {pmid38464687, year = {2024}, author = {Jahandust, M and Esmaeili, A}, title = {Construction of a new membrane bed biofilm reactor and yttria-stabilized zirconia for removing heavy metal pollutants.}, journal = {RSC advances}, volume = {14}, number = {12}, pages = {8150-8160}, pmid = {38464687}, issn = {2046-2069}, abstract = {The objective is to design a reactor with a composite new membrane bed biofilm reactor and yttria-stabilized zirconia. We constructed a valuable reactor using response surface methodology (RSM) for process optimization. The present system can remove heavy metal Pb from wastewater using a two-part biofilm reactor: the first reactor, which includes active sludge and media, was investigated; then, the second part, which includes membranes, was made. The amount of heavy metal removed from the effluent was measured at different pH and contact time. The results obtained from this study showed that the optimum conditions for obtaining the optimal removal efficiency separately, with a lead value of 40 mg L[-1] for the MBBR reactor, had the highest removal value of 55% and for the membrane with an input lead value of 20 ppm at pH = 12 call time 30 minutes equal to 85%. All analyses in this article have been repeated numerous times to prove the repeatability.}, } @article {pmid38463305, year = {2024}, author = {Levy, IK and Salustro, D and Battaglini, F and Lizarraga, L and Murgida, DH and Agusti, R and D'Accorso, N and Raventos Segura, D and González Palmén, L and Negri, RM}, title = {Quantification of Enzymatic Biofilm Removal Using the Sauerbrey Equation: Application to the Case of Pseudomonas protegens.}, journal = {ACS omega}, volume = {9}, number = {9}, pages = {10445-10458}, pmid = {38463305}, issn = {2470-1343}, abstract = {A methodology for the quantitative analysis of enzymatic removal of biofilms (BF) was developed, based on a quartz crystal microbalance (QCM) under stationary conditions. This was applied to the case of Pseudomonas protegens (PP) BFs, through a series of five enzymes, whose removal activity was screened using the presented methodology. The procedure is based on the following: when BFs can be modeled as rigid materials, QCM can be used as a balance under stationary conditions for determining the BFs mass reduction by enzymatic removal. For considering a BF as a rigid model, energy dissipation effects, associated with viscoelastic properties of the BF, must be negligible. Hence, a QCM system with detection of dissipation (referred to as QCM with dissipation) was used for evaluating the energy losses, which, in fact, resulted in negligible energy losses in the case of dehydrated PP BFs, validating the application of the Sauerbrey equation for the change of mass calculations. The stationary methodology reduces operating times and simplifies data analysis in comparison to dynamic approaches based on flow setups, which requires the incorporation of dissipation effects due to the liquid media. By carrying out QCM, glycosidase-type enzymes showed BF removal higher than 80% at enzyme concentration 50 ppm, reaching removal over 90% in the cases of amylase and cellulase/xylanase enzymes. The highest removal percentage produced a reduction from about 15 to 1 μg in the BF mass. Amylase enzyme was tested from below 50 to 1 ppm, reaching around 60% of removal at 1 ppm. The obtained results were supported by other instrumental techniques such as Raman spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy, high performance anion exchange chromatography, thermogravimetric analysis, and differential scanning calorimetry. The removal quantifications obtained with QCM were compared with those obtained by well-established screening techniques (UV-vis spectrophotometry using crystal violet and agar diffusion test). The proposed methodology expands the possibility of using a quartz microbalance to perform enzymatic activity screening.}, } @article {pmid38462558, year = {2024}, author = {Zhang, H and Mi, Z and Wang, J and Zhang, J}, title = {D-histidine combated biofilm formation and enhanced the effect of amikacin against Pseudomonas aeruginosa in vitro.}, journal = {Archives of microbiology}, volume = {206}, number = {4}, pages = {148}, pmid = {38462558}, issn = {1432-072X}, support = {No: 2022zhyx-C58//Research Fund of Anhui Institute of translational medicine/ ; No: 2022zhyx-C58//Research Fund of Anhui Institute of translational medicine/ ; No: 2022zhyx-C58//Research Fund of Anhui Institute of translational medicine/ ; No: 2022zhyx-C58//Research Fund of Anhui Institute of translational medicine/ ; }, abstract = {Pseudomonas aeruginosa is an opportunistic gram-negative pathogenic microorganism that poses a significant challenge in clinical treatment. Antibiotics exhibit limited efficacy against mature biofilm, culminating in an increase in the number of antibiotic-resistant strains. Therefore, novel strategies are essential to enhance the effectiveness of antibiotics against Pseudomonas aeruginosa biofilms. D-histidine has been previously identified as a prospective anti-biofilm agent. However, limited attention has been directed towards its impact on Pseudomonas aeruginosa. Therefore, this study was undertaken to explore the effect of D-histidine on Pseudomonas aeruginosa in vitro. Our results demonstrated that D-histidine downregulated the mRNA expression of virulence and quorum sensing (QS)-associated genes in Pseudomonas aeruginosa PAO1 without affecting bacterial growth. Swarming and swimming motility tests revealed that D-histidine significantly reduced the motility and pathogenicity of PAO1. Moreover, crystal violet staining and confocal laser scanning microscopy demonstrated that D-histidine inhibited biofilm formation and triggered the disassembly of mature biofilms. Notably, D-histidine increased the susceptibility of PAO1 to amikacin compared to that in the amikacin-alone group. These findings underscore the efficacy of D-histidine in combating Pseudomonas aeruginosa by reducing biofilm formation and increasing biofilm disassembly. Moreover, the combination of amikacin and D-histidine induced a synergistic effect against Pseudomonas aeruginosa biofilms, suggesting the potential utility of D-histidine as a preventive strategy against biofilm-associated infections caused by Pseudomonas aeruginosa.}, } @article {pmid38461606, year = {2024}, author = {Zheng, S and Li, J and Yan, W and Zhao, W and Ye, C and Yu, X}, title = {Biofilm formation and antioxidation were responsible for the increased resistance of N. eutropha to chloramination for drinking water treatment.}, journal = {Water research}, volume = {254}, number = {}, pages = {121432}, doi = {10.1016/j.watres.2024.121432}, pmid = {38461606}, issn = {1879-2448}, abstract = {Chloramination is an effective strategy for eliminating pathogens from drinking water and repressing their regrowth in water distribution systems. However, the inevitable release of NH4[+] potentially promotes nitrification and associated ammonia-oxidizing bacteria (AOB) contamination. In this study, AOB (Nitrosomona eutropha) were isolated from environmental water and treated with two disinfection stages (chloramine disinfection and chloramine residues) to investigate the occurrence mechanisms of AOB in chloramination. The results showed that N. eutropha had considerable resistance to monochloramine compared to Escherichia coli, whose inactivation rate constant was 19.4-fold lower. The higher resistance was attributed to high levels of extracellular polymer substances (EPS) in AOB, which contribute to AOB surviving disinfection and entering the distribution system. In AOB response to the chloramine residues stage, the respiratory activity of N. eutropha remained at a high level after three days of continuous exposure to high chloramine residue concentrations (0.5-1.5 mg/L). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) suggested that the mechanism of N. eutropha tolerance involved a significantly high expression of the intracellular oxidative stress-regulating (sodB, txrA) and protein-related (NE1545, NE1546) genes. Additionally, this process enhanced EPS secretion and promoted biofilm formation. Adhesion predictions based on the XDLVO theory corroborated the trend of biofilm formation. Overall, the naturally higher resistance contributed to the survival of AOB in primary disinfection; the enhanced antioxidant response of surviving N. eutropha accompanied by biofilm formation was responsible for their increased resistance to the residual chloramines.}, } @article {pmid38461600, year = {2024}, author = {Zuo, Z and Niu, C and Zhao, X and Lai, CY and Zheng, M and Guo, J and Hu, S and Liu, T}, title = {Biological bromate reduction coupled with in situ gas fermentation in H2/CO2-based membrane biofilm reactor.}, journal = {Water research}, volume = {254}, number = {}, pages = {121402}, doi = {10.1016/j.watres.2024.121402}, pmid = {38461600}, issn = {1879-2448}, abstract = {Bromate, a carcinogenic contaminant generated in water disinfection, presents a pressing environmental concern. While biological bromate reduction is an effective remediation approach, its implementation often necessitates the addition of organics, incurring high operational costs. This study demonstrated the efficient biological bromate reduction using H2/CO2 mixture as the feedstock. A membrane biofilm reactor (MBfR) was used for the efficient delivery of gases. Long-term reactor operation showed a high-level bromate removal efficiency of above 95 %, yielding harmless bromide as the final product. Corresponding to the short hydraulic retention time of 0.25 d, a high bromate removal rate of 4 mg Br/L/d was achieved. During the long-term operation, in situ production of volatile fatty acids (VFAs) by gas fermentation was observed, which can be regulated by controlling the gas flow. Three sets of in situ batch tests and two groups of ex situ batch tests jointly unravelled the mechanisms underpinning the efficient bromate removal, showing that the microbial bromate reduction was primarily driven by the VFAs produced from in situ gas fermentation. Microbial community analysis showed an increased abundance of Bacteroidota group from 4.0 % to 18.5 %, which is capable of performing syngas fermentation, and the presence of heterotrophic denitrifiers (e.g., Thauera and Brachymonas), which are known to perform bromate reduction. Together these results for the first time demonstrated the feasibility of using H2/CO2 mixture for bromate removal coupled with in situ VFAs production. The findings can facilitate the development of cost-effective strategies for groundwater and drinking water remediation.}, } @article {pmid38460558, year = {2024}, author = {Li, P and Yang, Y and Zhuang, LL and Hu, Z and Zhang, L and Ge, S and Qian, W and Tian, W and Wu, Y and Hu, HY}, title = {Effects of chemical oxygen demand and chloramphenicol on attached microalgae growth: Physicochemical properties and microscopic mass transfer in biofilm.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130561}, doi = {10.1016/j.biortech.2024.130561}, pmid = {38460558}, issn = {1873-2976}, abstract = {During the wastewater treatment and resource recovery process by attached microalgae, the chemical oxygen demand (COD) can cause biotic contamination in algal culture systems, which can be mitigated by adding an appropriate dosage of antibiotics. The transport of COD and additive antibiotic (chloramphenicol, CAP) in algal biofilms and their influence on algal physiology were studied. The results showed that COD (60 mg/L) affected key metabolic pathways, such as photosystem II and oxidative phosphorylation, improved biofilm autotrophic and heterotrophic metabolic intensities, increased nutrient demand, and promoted biomass accumulation by 55.9 %, which was the most suitable COD concentration for attached microalgae. CAP (5-10 mg/L) effectively stimulated photosynthetic pigment accumulation and nutrient utilization in pelagic microalgal cells. In conclusion, controlling the COD concentration (approximately 60 mg/L) in the medium and adding the appropriate CAP concentration (5-10 mg/L) are conducive to improving attached microalgal biomass production and resource recovery potential from wastewater.}, } @article {pmid38460236, year = {2024}, author = {Fan, L and Liu, S and Dai, H and Yuan, L and Yang, Z and Jiao, XA}, title = {Genotype-phenotype evaluation of the heterogeneity in biofilm formation by diverse Bacillus licheniformis strains isolated from dairy products.}, journal = {International journal of food microbiology}, volume = {416}, number = {}, pages = {110660}, doi = {10.1016/j.ijfoodmicro.2024.110660}, pmid = {38460236}, issn = {1879-3460}, abstract = {The spoilage bacterium Bacillus licheniformis has been identified as a quick and strong biofilm former in the dairy industry. In our previous study, intra-species variation in bacterial biofilms has been observed in diverse B. licheniformis strains from different genetic backgrounds; however, the mechanisms driving the observed heterogeneity of biofilms remain to be determined. In this study, the genotype-phenotype evaluation of the heterogeneity in biofilm formation of four B. licheniformis strains were examined. The heterogeneity in biofilm phenotype was accessed in aspects of bacterial growth and motility, cell viability, biofilm matrix production, and biofilm architectures. The underlying mechanisms of the intra-species variability in biofilms were also explored by whole genome resequencing (WGR). Results from bacterial motility tests showed a diverse motility among the strains, but there was no clear correlation between bacterial motility and biofilm formation. The cell viability results showed a different number of live cells in biofilms at the intra-species level. Analysis of chemical components in biofilm matrix demonstrated the great intra-species differences regarding extracellular matrix composition, and a negative correlation between biofilm formation on stainless steel and the protein: carbohydrate ratio in biofilm matrix was observed. Confocal laser scanning microscopy analysis also revealed the intra-species variability by showing great differences in general properties of B. licheniformis biofilms. WGR results identified important pathways involved in biofilm formation, such as two-component systems, quorum sensing, starch and sucrose metabolism, ABC transporters, glyoxylate and dicarboxylate metabolism, purine metabolism, and a phosphotransferase system. Overall, the above results emphasize the necessity of exploring the intra-species variation in biofilms, and would provide in-depth knowledge for designing efficient biofilm control strategies in the dairy industry.}, } @article {pmid38459593, year = {2024}, author = {Lei, Z and Liang, H and Sun, W and Chen, Y and Huang, Z and Yu, B}, title = {A biodegradable PVA coating constructed on the surface of the implant for preventing bacterial colonization and biofilm formation.}, journal = {Journal of orthopaedic surgery and research}, volume = {19}, number = {1}, pages = {175}, pmid = {38459593}, issn = {1749-799X}, support = {2022A1515011292//Basic and Applied Basic Research Foundation of Guangdong Province/ ; 81974323//National Natural Science Foundation of China/ ; }, abstract = {BACKGROUND: Bone implant infections pose a critical challenge in orthopedic surgery, often leading to implant failure. The potential of implant coatings to deter infections by hindering biofilm formation is promising. However, a shortage of cost-effective, efficient, and clinically suitable coatings persists. Polyvinyl alcohol (PVA), a prevalent biomaterial, possesses inherent hydrophilicity, offering potential antibacterial properties.

METHODS: This study investigates the PVA solution's capacity to shield implants from bacterial adhesion, suppress bacterial proliferation, and thwart biofilm development. PVA solutions at concentrations of 5%, 10%, 15%, and 20% were prepared. In vitro assessments evaluated PVA's ability to impede bacterial growth and biofilm formation. The interaction between PVA and mCherry-labeled Escherichia coli (E. coli) was scrutinized, along with PVA's therapeutic effects in a rat osteomyelitis model.

RESULTS: The PVA solution effectively restrained bacterial proliferation and biofilm formation on titanium implants. PVA solution had no substantial impact on the activity or osteogenic potential of MC3T3-E1 cells. Post-operatively, the PVA solution markedly reduced the number of Staphylococcus aureus and E. coli colonies surrounding the implant. Imaging and histological scores exhibited significant improvements 2 weeks post-operation. Additionally, no abnormalities were detected in the internal organs of PVA-treated rats.

CONCLUSIONS: PVA solution emerges as an economical, uncomplicated, and effective coating material for inhibiting bacterial replication and biofilm formation on implant surfaces, even in high-contamination surgical environments.}, } @article {pmid38458983, year = {2024}, author = {Koura, Y and Tomiyama, K and Kunimatsu, Y and Hamada, N and Mukai, Y}, title = {Microbial shift of oral biofilm associated with remineralization of root dentin lesions.}, journal = {American journal of dentistry}, volume = {37}, number = {1}, pages = {47-52}, pmid = {38458983}, issn = {0894-8275}, abstract = {PURPOSE: To examine the relationship between remineralization of incipient root dentin lesions and the presence of polymicrobial biofilms, as well as examine changes in microbial composition.

METHODS: Bovine root dentin disks used as specimens for biofilm formation, were cultured using saliva from a single donor. Amsterdam Active Attachment biofilm model was used to grow biofilms. The culture medium was McBain 2005 with 0.2% sucrose and 0.4 ppm F as sodium fluoride. After cultivation for 48 hours to achieve demineralization, a control group (n=10) was obtained and the other specimens were further cultured for 336 hours in two types of remineralization culture medium, with sucrose (S+) and without sucrose (S-), through continuous anaerobic incubation (10% CO2,10% H2, 80% N2). Then half of the specimens cultured in the S- medium were transferred to the S+ medium for an additional 48 hours resulting in three experimental groups S(+) (n=10), S(-) (n=10), and S(-)de (n=10), respectively. Experiment 1: Transverse microradiography (TMR) analysis - Immediately after respective culture treatments, integrated mineral loss (IML) and lesion depth (LD) in the dentin specimens were analyzed by TMR. Experiment 2: Microbiome analysis - Sequence data of the 16S rRNA gene of each sample was obtained using MiSeq, and partial base sequences were determined. Next-generation sequencing was performed to determine the taxonomic groups of fungi present in the biofilm samples.

RESULTS: Experiment 1: In the control group, formation of dentin demineralization lesions by polymicrobial species biofilms was confirmed. The S(-) group showed significantly decreased IML and shallower LD compared to the control group. The S(-)de group showed a significant increase in IML and LD compared to the S(-) group. Experiment 2: There were statistically significant differences in microbiome between the control group and each of the three experimental groups, both at the genus and species levels. A significant difference in genus was observed between the S(-) group and the S(-)de group.

CLINICAL SIGNIFICANCE: The confirmation of the possibility of microbial shift occurring during the remineralization process of root caries will lead to the development of new remineralization therapies.}, } @article {pmid38458453, year = {2024}, author = {Mkpuma, VO and Moheimani, NR and Ennaceri, H}, title = {Biofilm and suspension-based cultivation of microalgae to treat anaerobic digestate food effluent (ADFE).}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {171320}, doi = {10.1016/j.scitotenv.2024.171320}, pmid = {38458453}, issn = {1879-1026}, abstract = {Anaerobic digestion of organic waste produces effluent (ADE) that requires further treatment. Biofilm-based microalgal cultivation is a favoured approach to ADE treatment. This study compared Chlorella sp. MUR 268 and Scenedesmus sp. MUR 269 in biofilm and suspension cultures to treat anaerobic digestate food effluent (ADFE). Chlorella sp. MUR 268 biofilm had significantly higher biomass (50.38 g m[-2]) than Scenedesmus sp. biofilm (9.39 g m[-2]). Conversely, Scenedesmus sp. yielded 1.5 times more biomass (1.2 g L[-1]) than Chlorella sp. in suspension. Chlorella sp. biofilm had 49.3 % higher areal productivity than suspension, while Scenedesmus sp. showed 87.3 % higher areal growth in suspension. Chlorella sp. MUR 268 and Scenedesmus sp. MUR 269 significantly removed nutrients in ADFE. In suspension, COD, ammoniacal nitrogen, and phosphate were reduced to 94.9, 5.2, and 5.98 mg L[-1] for Chlorella sp. MUR 268, and 245, 2.89, and 3.22 mg L[-1] for Scenedesmus sp. MUR 269, respectively. In biofilm, Chlorella sp. MUR 268 achieved reductions to 149.9, 1.16, and 3.57 mg L[-1], while Scenedesmus sp. MUR 269 achieved 100.2, 6.9 and 2.07 mg L[-1]. Most of these values are below the recommended effluent discharge standard, highlighting the efficacy of this system in ADFE treatment. Biofilm cultures fixed 68-81 % of removed nitrogen was fixed in biomass, while in suspension, only 55-71 % ended in the biomass. Chlorella sp. MUR 268 biofilm fixed 88 % of removed phosphorus, while Scenedesmus sp. MUR 269 suspension fixed more phosphorus (55 %) than the biofilm counterpart (34 %). This biofilm design offers advantages like simplified, cost-effective operation, easy biomass recovery, and reduced water usage.}, } @article {pmid38457119, year = {2024}, author = {Pucelik, B and Barzowska, A and Sułek, A and Werłos, M and Dąbrowski, JM}, title = {Refining antimicrobial photodynamic therapy: effect of charge distribution and central metal ion in fluorinated porphyrins on effective control of planktonic and biofilm bacterial forms.}, journal = {Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology}, volume = {}, number = {}, pages = {}, pmid = {38457119}, issn = {1474-9092}, support = {2016/22/E/NZ7/00420//Narodowe Centrum Nauki/ ; }, abstract = {Antibiotic resistance represents a pressing global health challenge, now acknowledged as a critical concern within the framework of One Health. Photodynamic inactivation of microorganisms (PDI) offers an attractive, non-invasive approach known for its flexibility, independence from microbial resistance patterns, broad-spectrum efficacy, and minimal risk of inducing resistance. Various photosensitizers, including porphyrin derivatives have been explored for pathogen eradication. In this context, we present the synthesis, spectroscopic and photophysical characteristics as well as antimicrobial properties of a palladium(II)-porphyrin derivative (PdF2POH), along with its zinc(II)- and free-base counterparts (ZnF2POH and F2POH, respectively). Our findings reveal that the palladium(II)-porphyrin complex can be classified as an excellent generator of reactive oxygen species (ROS), encompassing both singlet oxygen (Φ△ = 0.93) and oxygen-centered radicals. The ability of photosensitizers to generate ROS was assessed using a variety of direct (luminescence measurements) and indirect techniques, including specific fluorescent probes both in solution and in microorganisms during the PDI procedure. We investigated the PDI efficacy of F2POH, ZnF2POH, and PdF2POH against both Gram-negative and Gram-positive bacteria. All tested compounds proved high activity against Gram-positive species, with PdF2POH exhibiting superior efficacy, leading to up to a 6-log reduction in S. aureus viability. Notably, PdF2POH-mediated PDI displayed remarkable effectiveness against S. aureus biofilm, a challenging target due to its complex structure and increased resistance to conventional treatments. Furthermore, our results show that PDI with PdF2POH is more selective for bacterial than for mammalian cells, particularly at lower light doses (up to 5 J/cm[2] of blue light illumination). This enhanced efficacy of PdF2POH-mediated PDI as compared to ZnF2POH and F2POH can be attributed to more pronounced ROS generation by palladium derivative via both types of photochemical mechanisms (high yields of singlet oxygen generation as well as oxygen-centered radicals). Additionally, PDI proved effective in eliminating bacteria within S. aureus-infected human keratinocytes, inhibiting infection progression while preserving the viability and integrity of infected HaCaT cells. These findings underscore the potential of metalloporphyrins, particularly the Pd(II)-porphyrin complex, as promising photosensitizers for PDI in various bacterial infections, warranting further investigation in advanced infection models.}, } @article {pmid38456817, year = {2024}, author = {Feng, W and Chittò, M and Xie, W and Ren, Q and Liu, F and Kang, X and Zhao, D and Li, G and Moriarty, TF and Wang, X}, title = {Poly(d-amino acid) Nanoparticles Target Staphylococcal Growth and Biofilm Disassembly by Interfering with Peptidoglycan Synthesis.}, journal = {ACS nano}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsnano.3c10983}, pmid = {38456817}, issn = {1936-086X}, abstract = {d-Amino acids are signals for biofilm disassembly. However, unexpected metabolic pathways severely attenuate the utilization of d-amino acids in biofilm disassembly, resulting in unsatisfactory efficiency. Herein, three-dimensional poly(d-amino acid) nanoparticles (NPs), which possess the ability to block intracellular metabolism, are constructed with the aim of disassembling the biofilms. The obtained poly(α-N-acryloyl-d-phenylalanine)-block-poly(β-N-acryloyl-d-aminoalanine NPs (denoted as FA NPs) present α-amino groups and α-carboxyl groups of d-aminoalanine on their surface, which guarantees that FA NPs can effectively insert into bacterial peptidoglycan (PG) via the mediation of PG binding protein 4 (PBP4). Subsequently, the FA NPs trigger the detachment of amyloid-like fibers that connect to the PG and reduce the number of polysaccharides and proteins in extracellular polymeric substances (EPS). Finally, FA NPs damage the structural stability of EPS and lead to the disassembly of the biofilm. Based on this feature, FA NPs significantly enhance the killing efficacy of encapsulated sitafloxacin sesquihydrate (Sita) by facilitating the penetration of Sita within the biofilm, achieving complete elimination of Staphylococcal biofilm in mice. Therefore, this study strongly demonstrates that FA NPs can effectively improve biofilm disassembly efficacy and provide great potential for bacterial biofilm infection treatment.}, } @article {pmid38454786, year = {2024}, author = {Milovanović, J and Božić, DD and Pavlović, B and Jotić, A and Brkić, S and Ćirković, I}, title = {Biofilm-producing Bacteria and Quality of Life after Endoscopic Sinus Surgery in Patients with Chronic Rhinosinusitis with Nasal Polyposis.}, journal = {American journal of rhinology & allergy}, volume = {}, number = {}, pages = {19458924241236233}, doi = {10.1177/19458924241236233}, pmid = {38454786}, issn = {1945-8932}, abstract = {BACKGROUND: Chronic rhinosinusitis (CRS) is one of the most common health disorders in humans and has a major impact on health-related quality of life (HRQoL). Of the many factors contributing to the etiology of CRS, less is known about the correlation between CRS and bacterial biofilms and their impact on HRQoL.

OBJECTIVE: The aim of this prospective study was to investigate the relationship between biofilm-producing bacteria and patients' objective findings and HRQoL.

METHODS: Forty-eight patients with CRSwNP were enrolled in a 12-month prospective study. The Lund-Mackay (LM) CT and endoscopic Lund-Kennedy (LK) scores were obtained before endoscopic sinus surgery (ESS), and patients completed the HRQoL instruments: the 22-item Sinonasal Outcome Test (SNOT-22), the 36-item Short Questionnaire (SF-36), and the visual analog scale (VAS). A sinus culture was obtained at ESS, bacteria were isolated, and in vitro quantification of the biofilm was performed. The LK score and HRQoL were determined postoperatively at months 1, 3, 6, and 12.

RESULTS: The most common bacterial isolates in patients with CRSwNP were Staphylococcus aureus (28%), coagulase-negative staphylococci (52%), and Pseudomonas aeruginosa (8%). Preoperatively, the highest LM and LK scores were found in patients with strong biofilm producers. Postoperative LK scores were significantly reduced in all patients. Postoperative VAS scores were significantly reduced from month 1 to month 12 postoperatively. Patients with strong biofilm producers had significantly worse nasal blockage, secretion, headache, facial pressure and pain, and loss of smell preoperatively, compared to patients with low biofilm producers. The most significant reduction in preoperative scores SNOT-22 and SF-36 (excluding physical functioning) was seen in patients with S. aureus and P. aeruginosa.

CONCLUSIONS: Patients with strong biofilm producers had higher LK and LM scores preoperatively, and greater improvement in LK and HRQoL scores postoperatively. Microbiologic surveillance of all CRS patients is recommended.}, } @article {pmid38452867, year = {2024}, author = {Maezono, H and Klanliang, K and Shimaoka, T and Asahi, Y and Takahashi, Y and Wang, Z and Shen, Y and Haapasalo, M and Hayashi, M}, title = {Effects of sodium hypochlorite concentration and application time on bacteria in an ex vivo polymicrobial biofilm model.}, journal = {Journal of endodontics}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.joen.2024.02.020}, pmid = {38452867}, issn = {1878-3554}, abstract = {INTRODUCTION: In endodontic treatment, it is important to remove or inactivate biofilms in the root canal system. We investigated the effects of different concentrations and application times of sodium hypochlorite (NaOCl) on the viability of bacteria in ex vivo polymicrobial biofilms of different maturation levels.

METHODS: Polymicrobial biofilms were prepared from dental plaque samples and grown for 1, 2, and 3 weeks under anaerobic conditions on collagen-coated hydroxy apatite discs as an ex vivo biofilm model. The biofilms were then exposed to NaOCl at concentrations ranging from 0.1% to 2% for 1 or 3 min. The control group was exposed to sterile distilled water. Viability staining was performed and examined by confocal laser scanning microscopy to determine the percentage of biofilm bacteria killed by NaOCl. Scanning electron microscopy was also performed to visually examine the biofilms.

RESULTS: Application of NaOCl at 0.5% to 2% for both 1 and 3 min killed significantly more bacteria when compared to the controls (P < 0.05). Cell viability tended to be lower after the application of NaOCl for 3 min than that for 1 min.

CONCLUSION: Our experiments using an ex vivo model showed that within the range of 0.1% to 2% of NaOCl, higher NaOCl concentrations and longer application times were more effective in killing biofilm bacteria, and that mature biofilms were more resistant to NaOCl than younger biofilms.}, } @article {pmid38452830, year = {2024}, author = {Mohan, MS and Salim, SA and Ranganathan, S and Parasuraman, P and Anju, VT and Ampasala, DR and Dyavaiah, M and Lee, JK and Busi, S}, title = {Attenuation of Las/Rhl quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 by artocarpesin.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106609}, doi = {10.1016/j.micpath.2024.106609}, pmid = {38452830}, issn = {1096-1208}, abstract = {The emergence of multidrug resistance and increased pathogenicity in microorganisms is conferred by the presence of highly synchronized cell density dependent signalling pathway known as quorum sensing (QS). The QS hierarchy is accountable for the secretion of virulence phenotypes, biofilm formation and drug resistance. Hence, targeting the QS phenomenon could be a promising strategy to counteract the bacterial virulence and drug resistance phenomenon. In the present study, artocarpesin (ACN), a 6-prenylated flavone was investigated for its capability to quench the synthesis of QS regulated virulence factors. From the results, ACN showed significant inhibition of secreted virulence phenotypes such as pyocyanin (80%), rhamnolipid (79%), protease (69%), elastase (84%), alginate (88%) and biofilm formation (88%) in opportunistic pathogen, Pseudomonas aeruginosa PAO1. Further, microscopic observation of biofilm confirmed a significant reduction in biofilm matrix when P. aeruginosa PAO1 was supplemented with ACN at its sub-MIC concentration. Quantitative gene expression studies showed the promising aspects of ACN in down regulation of several QS regulatory genes associated with production of virulence phenotypes. Upon treatment with sub-MIC of ACN, the bacterial colonization in the gut of Caenorhabditis elegans was potentially reduced and the survival rate was greatly improved. The promising QS inhibition activities were further validated through in silico studies, which put an insight into the mechanism of QS inhibition. Thus, ACN could be considered as possible drug candidate targeting chronic microbial infections.}, } @article {pmid38450220, year = {2023}, author = {Ebrahimi Tarki, F and Zarrabi, M and Abdiali, A and Sharbatdar, M}, title = {Integration of Machine Learning and Structural Analysis for Predicting Peptide Antibiofilm Effects: Advancements in Drug Discovery for Biofilm-Related Infections.}, journal = {Iranian journal of pharmaceutical research : IJPR}, volume = {22}, number = {1}, pages = {e138704}, pmid = {38450220}, issn = {1726-6890}, abstract = {BACKGROUND: The rise of antibiotic resistance has become a major concern, signaling the end of the golden age of antibiotics. Bacterial biofilms, which exhibit high resistance to antibiotics, significantly contribute to the emergence of antibiotic resistance. Therefore, there is an urgent need to discover new therapeutic agents with specific characteristics to effectively combat biofilm-related infections. Studies have shown the promising potential of peptides as antimicrobial agents.

OBJECTIVES: This study aimed to establish a cost-effective and streamlined computational method for predicting the antibiofilm effects of peptides. This method can assist in addressing the intricate challenge of designing peptides with strong antibiofilm properties, a task that can be both challenging and costly.

METHODS: A positive library, consisting of peptide sequences with antibiofilm activity exceeding 50%, was assembled, along with a negative library containing quorum-sensing peptides. For each peptide sequence, feature vectors were calculated, while considering the primary structure, the order of amino acids, their physicochemical properties, and their distributions. Multiple supervised learning algorithms were used to classify peptides with significant antibiofilm effects for subsequent experimental evaluations.

RESULTS: The computational approach exhibited high accuracy in predicting the antibiofilm effects of peptides, with accuracy, precision, Matthew's correlation coefficient (MCC), and F1 score of 99%, 99%, 0.97, and 0.99, respectively. The performance level of this computational approach was comparable to that of previous methods. This study introduced a novel approach by combining the feature space with high antibiofilm activity.

CONCLUSIONS: In this study, a reliable and cost-effective method was developed for predicting the antibiofilm effects of peptides using a computational approach. This approach allows for the identification of peptide sequences with substantial antibiofilm activities for further experimental investigations. Accessible source codes and raw data of this study can be found online (hiABF), providing easy access and enabling future updates.}, } @article {pmid38449981, year = {2024}, author = {Nair, P and Sankar, S and Neelusree, P}, title = {Study on Biofilm Formation Among Enterococcus Isolates and Association With Their Antibiotic Resistance Patterns.}, journal = {Cureus}, volume = {16}, number = {2}, pages = {e53594}, pmid = {38449981}, issn = {2168-8184}, abstract = {Background Enterococci are a part of the normal intestinal flora of humans. They have emerged as one of the leading causes of nosocomial infection. The evolved antibiotic resistance mechanisms coupled with the virulence properties of enterococci have made it a successful pathogen. Aim This study aimed to determine the ability of biofilm formation among the clinical enterococci isolates and the antimicrobial resistance pattern of the strains. Materials and methods Clinical samples of patients who attended Saveetha Medical College and Hospital, Chennai, India, over six months. Identification and characterization of Enterococcus species were done using various biochemical tests. Antibiotic susceptibility patterns for each isolate were performed using the Kirby- Bauer disc diffusion method. Results The formation of biofilm formation was detected using the microtiter plate method. In total, 90 Enterococcus species were isolated; Enterococcus faecalis were 63 (70%), Enterococcus faecium were 25 (28%) and Enterococcus gallinarum were 2 (2%)independently. E. faecalis displayed advanced resistance rates compared to other Enterococcus species. Resistance against penicillin was found in 42 strains (47%) and resistance to ampicillin was observed in 39 strains (43%). This was followed by resistance to high-level gentamicin in 35 strains (39%) and resistance to ciprofloxacin in 32 strains (36%). Resistance to vancomycin and linezolid also were noted in some strains. Conclusion Our results indicate that E. faecalis exhibits an increasing rate of antimicrobial resistance but lower biofilm conformation. The unique traits of E. faecalis raise concerns for the associated infections, especially hospital-acquired infections.}, } @article {pmid38449645, year = {2024}, author = {Yousefi, L and Kadkhoda, H and Shirmohammadi, M and Moaddab, SY and Ghotaslou, R and Tahereh Pirzadeh, and Sadeghi, J and Somi, MH and Ahangarzadeh Rezaee, M and Ganbarov, K and Samadi Kafil, H}, title = {CRISPR-like sequences association with antibiotic resistance and biofilm formation in Helicobacter pylori clinical isolates.}, journal = {Heliyon}, volume = {10}, number = {5}, pages = {e26809}, pmid = {38449645}, issn = {2405-8440}, abstract = {Role of clustered regularly interspaced short palindromic repeats (CRISPR)-like sequences in antibiotic resistance and biofilm formation isn't clear. This study investigated association of CRISPR-like sequences with antibiotic resistance and biofilm formation in H. pylori isolates. Thirty-six of H. pylori isolates were studied for existence of CRISPR-like sequences using PCR method and their correlation with biofilm formation and antibiotic resistance. Microtiter-plate technique was utilized for investigating antibiotic resistance profile of isolates against amoxicillin, tetracycline, metronidazole and clarithromycin. Biofilm formation of isolates was analyzed by microtiter-plate-based-method. Out of 23 CRISPR-like positive isolates, 19 had ability of biofilm formation and 7 of 13 CRISPR-like negative isolates were able to form biofilm (Pvalue = 0.445). In CRISPR-like positive isolates, 11 (48%), 18 (78%), 18 (78%) and 23 (100%) were resistant to amoxicillin, tetracycline, metronidazole and clarithromycin, respectively. Since CRISPR-like sequences have role in antibiotic resistance, may be applied as genetic markers of antibiotic resistance. But there was no substantial correlation between biofilm formation and existence of CRISPR-like sequences. These results indicate possible importance of CRISPR-like sequences on acquisition of resistance to antibiotics in this bacterium.}, } @article {pmid38447448, year = {2024}, author = {Mishra, M and Ballal, A and Rath, D and Rath, A}, title = {Novel silver nanoparticle-antibiotic combinations as promising antibacterial and anti-biofilm candidates against multiple-antibiotic resistant ESKAPE microorganisms.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {236}, number = {}, pages = {113826}, doi = {10.1016/j.colsurfb.2024.113826}, pmid = {38447448}, issn = {1873-4367}, abstract = {HYPOTHESIS: The emergence of Multiple Antibiotic Resistance (MAR) in ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens is a global challenge to public health. The inherent antimicrobial nature of silver nanoparticles (AgNPs) makes them promising antimicrobial candidates against antibiotic-resistant pathogens. This study explores the combination of AgNPs with antibiotics (SACs) to create new antimicrobial agents effective against MAR ESKAPE microorganisms.

METHODS: AgNPs were synthesized using Streptococcus pneumoniae ATCC 49619 and characterized for structure and surface properties. The SACs were tested against ESKAPE microorganisms using growth kinetics and time-kill curve methods. The effect of SACs on bacterial biofilms and the disruption of cell membranes was determined. The in-vitro cytotoxicity effect of the AgNPs was also studied.

FINDINGS: The synthesized AgNPs (spherical, 7.37±4.55 nm diameter) were antimicrobial against MAR ESKAPE microorganisms. The SACs showed synergy with multiple conventional antibiotics, reducing their antibacterial concentrations up to 32-fold. Growth kinetics and time-kill studies confirmed the growth retardation effect and bactericidal activity of SACs. Mechanistic studies suggested that these biofilm-eradicating SACs probably resulted in the loss of bacterial cell membrane integrity, leading to leakage of the cytoplasmic content. The AgNPs were highly cytotoxic against skin melanoma cells but non-cytotoxic to normal Vero cells.}, } @article {pmid38444208, year = {2024}, author = {Erol, HB and Kaskatepe, B and Yildiz, S and Altanlar, N and Bayrakdar, F}, title = {Characterization of two bacteriophages specific to Acinetobacter baumannii and their effects on catheters biofilm.}, journal = {Cell biochemistry and function}, volume = {42}, number = {2}, pages = {e3966}, doi = {10.1002/cbf.3966}, pmid = {38444208}, issn = {1099-0844}, support = {18L0237009//Ankara Universitesi/ ; }, mesh = {Humans ; *Acinetobacter baumannii ; *Bacteriophages/genetics ; Biofilms ; Catheters ; Databases, Factual ; }, abstract = {Multidrug-resistant strains of Acinetobacter baumannii cause major nosocomial infections. Bacteriophages that are specific to the bacterial species and destroy bacteria can be effectively used for treatment. In this study, we characterized lytic bacteriophages specific to A. baumannii strains. We isolated lytic bacteriophages from environmental water samples and then investigated their morphology, host range, growth characteristics, stability, genome analysis, and biofilm destruction on the catheter surface. Our results showed that the efficacy of the phages varied between 32% and 78%, tested on 78 isolates of A. baumannii; 80 phages were isolated, and two lytic bacteriophages, vB_AbaP_HB01 (henceforth called C2 phage) and vB_AbaM_HB02 (henceforth called K3 phage), were selected for characterization. Electron microscopy scans revealed that the C2 and K3 phages were members of the Podoviridae and Myoviridae families, respectively. Whole-genome sequencing revealed that the sequence of the C2 phage is available in the NCBI database (accession number: OP917929.1), and it was found sequence identity with Acinetobacter phage AB1 18%, the K3 phage DNA sequence is closely related to Acinetobacter phage vB_AbaM_phiAbaA1 (94% similarity). The cocktail of C2 and K3 phages demonstrated a promising decrease in the bacterial cell counts of the biofilm after 4 h. Under a scanning electron microscope, the cocktail treatment destructed the biofilm on the catheter. We propose that the phage cocktail could be a strong alternative to antibiotics to control the A. baumannii biofilm in catheter infections.}, } @article {pmid38444124, year = {2024}, author = {Naseef Pathoor, N and Viswanathan, A and Wadhwa, G and Ganesh, PS}, title = {Understanding the biofilm development of Acinetobacter baumannii and novel strategies to combat infection.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13399}, pmid = {38444124}, issn = {1600-0463}, abstract = {Acinetobacter baumannii (A. baumannii) is a Gram-negative, nonmotile, and aerobic bacillus emerged as a superbug, due to increasing the possibility of infection and accelerating rates of antimicrobial agents. It is recognized as a nosocomial pathogen due to its ability to form biofilms. These biofilms serve as a defensive barrier, increase antibiotic resistance, and make treatment more difficult. As a result, the current situation necessitates the rapid emergence of novel therapeutic approaches to ensure successful treatment outcomes. This review explores the intricate relationship between biofilm formation and antibiotic resistance in A. baumannii, emphasizing the role of key virulence factors and quorum sensing (QS) mechanisms that will lead to infections and facilitate insight into developing innovative method to control A. baumannii infections. Furthermore, the review article looks into promising approaches for preventing biofilm formation on medically important surfaces and potential therapeutic methods for eliminating preformed biofilms, which can address biofilm-associated A. baumannii infections. Modern advances in emerging therapeutic options such as antimicrobial peptide (AMPs), nanoparticles (NPs), bacteriophage therapy, photodynamic therapy (PDT), and other biofilm inhibitors can assist readers understand the current landscape and future prospects for effectively treating A. baumannii biofilm infections.}, } @article {pmid38443393, year = {2024}, author = {Prentice, JA and van de Weerd, R and Bridges, AA}, title = {Cell-lysis sensing drives biofilm formation in Vibrio cholerae.}, journal = {Nature communications}, volume = {15}, number = {1}, pages = {2018}, pmid = {38443393}, issn = {2041-1723}, support = {R00AI158939//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; 2302-17//Damon Runyon Cancer Research Foundation (Cancer Research Fund of the Damon Runyon-Walter Winchell Foundation)/ ; }, abstract = {Matrix-encapsulated communities of bacteria, called biofilms, are ubiquitous in the environment and are notoriously difficult to eliminate in clinical and industrial settings. Biofilm formation likely evolved as a mechanism to protect resident cells from environmental challenges, yet how bacteria undergo threat assessment to inform biofilm development remains unclear. Here we find that population-level cell lysis events induce the formation of biofilms by surviving Vibrio cholerae cells. Survivors detect threats by sensing a cellular component released through cell lysis, which we identify as norspermidine. Lysis sensing occurs via the MbaA receptor with genus-level specificity, and responsive biofilm cells are shielded from phage infection and attacks from other bacteria. Thus, our work uncovers a connection between bacterial lysis and biofilm formation that may be broadly conserved among microorganisms.}, } @article {pmid38443373, year = {2024}, author = {Dzofou Ngoumelah, D and Heggeset, TMB and Haugen, T and Sulheim, S and Wentzel, A and Harnisch, F and Kretzschmar, J}, title = {Effect of model methanogens on the electrochemical activity, stability, and microbial community structure of Geobacter spp. dominated biofilm anodes.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {17}, pmid = {38443373}, issn = {2055-5008}, support = {57381414//Deutscher Akademischer Austauschdienst (German Academic Exchange Service)/ ; 731101//EC | Horizon 2020 Framework Programme (EU Framework Programme for Research and Innovation H2020)/ ; }, abstract = {Combining anaerobic digestion (AD) and microbial electrochemical technologies (MET) in AD-MET holds great potential. Methanogens have been identified as one cause of decreased electrochemical activity and deterioration of Geobacter spp. biofilm anodes. A better understanding of the different interactions between methanogenic genera/species and Geobacter spp. biofilms is needed to shed light on the observed reduction in electrochemical activity and stability of Geobacter spp. dominated biofilms as well as observed changes in microbial communities of AD-MET. Here, we have analyzed electrochemical parameters and changes in the microbial community of Geobacter spp. biofilm anodes when exposed to three representative methanogens with different metabolic pathways, i.e., Methanosarcina barkeri, Methanobacterium formicicum, and Methanothrix soehngenii. M. barkeri negatively affected the performance and stability of Geobacter spp. biofilm anodes only in the initial batches. In contrast, M. formicicum did not affect the stability of Geobacter spp. biofilm anodes but caused a decrease in maximum current density of ~37%. M. soehngenii induced a coloration change of Geobacter spp. biofilm anodes and a decrease in the total transferred charge by ~40%. Characterization of biofilm samples after each experiment by 16S rRNA metabarcoding, whole metagenome nanopore sequencing, and shotgun sequencing showed a higher relative abundance of Geobacter spp. after exposure to M. barkeri as opposed to M. formicicum or M. soehngenii, despite the massive biofilm dispersal observed during initial exposure to M. barkeri.}, } @article {pmid38442601, year = {2024}, author = {Huang, P and Li, Z and Liu, R and Bartlam, M and Wang, Y}, title = {Polystyrene nanoparticles induce biofilm formation in Pseudomonas aeruginosa.}, journal = {Journal of hazardous materials}, volume = {469}, number = {}, pages = {133950}, doi = {10.1016/j.jhazmat.2024.133950}, pmid = {38442601}, issn = {1873-3336}, abstract = {In recent years, micro/nanoplastics have garnered widespread attention due to their ecological risks. In this study, we investigated the effects of polystyrene nanoparticles (PS-NPs) of different sizes on the growth and biofilm formation of Pseudomonas aeruginosa PAO1. The results demonstrated that exposure to certain concentrations of PS-NPs significantly promoted bacterial biofilm formation. Meanwhile, we comprehensively revealed its mechanism whereby PS-NPs induced oxidative stress and altered bacterial membrane permeability by contacting or penetrating bacterial membranes. To counteract the stimulation by PS-NPs and reduce their toxicity, bacteria enhanced biofilm formation by upregulating the expression of biofilm-related genes, increasing EPS and virulence factors secretion, and enhancing bacterial motility through the participation of the quorum sensing (QS) system. Additionally, we also found that exposure to PS-NPs enhanced bacterial antibiotic resistance, posing a challenge to antimicrobial therapy. Our study reveals the toxic effects of nanoplastics and the defense mechanisms of bacteria, which has important implications for the risk assessment and management of environmental nanoplastics.}, } @article {pmid38441817, year = {2024}, author = {Alahyaribeik, S and Nazarpour, M}, title = {Peptide recovery from chicken feather keratin and their anti-biofilm properties against methicillin-resistant Staphylococcus aureus (MRSA).}, journal = {World journal of microbiology & biotechnology}, volume = {40}, number = {4}, pages = {123}, pmid = {38441817}, issn = {1573-0972}, abstract = {Bacteria have the potential to adhere to abiotic surfaces, which has an undesirable effect in the food industry because they can survive for sustained periods through biofilm formation. In this study, an antibacterial peptide (ABP), with a molecular mass of 3861 Da, was purified from hydrolyzed chicken feathers using a locally isolated keratinolytic bacterium, namely Rhodococcus erythropolis, and its antibacterial and antibiofilm potential were investigated against planktonic and biofilm cells of Methicillin-Resistant Staphylococcus Aureus (MRSA). The results demonstrated that purified ABP showed the growth inhibition of MRSA cells with the minimum inhibitory concentration (MIC) of 45 µg/ml and disrupted MRSA biofilm formation at a concentration of 200 ug/ml, which results were confirmed by scanning electron micrograph (SEM). Moreover, the secondary structures of the peptide were assessed as part of the FTIR analysis to evaluate its mode of action. ExPASy tools were used to predict the ABP sequence, EPCVQUQDSRVVIQPSPVVVVTLPGPILSSFPQNTA, from a chicken feather keratin sequence database following in silico digestion by trypsin. Also, ABP had 54.29% hydrophobic amino acids, potentially contributing to its antimicrobial activity. The findings of toxicity prediction of the peptide by the ToxinPred tool revealed that ABP had non-toxic effects. Thus, these results support the potential of this peptide to be used as an antimicrobial agent for the treatment or prevention of MRSA biofilm formation in feed, food, or pharmaceutical applications.}, } @article {pmid38441647, year = {2024}, author = {Patel, RJ and Nerurkar, AS}, title = {Thauera sp. for efficient nitrate removal in continuous denitrifying moving bed biofilm reactor.}, journal = {Bioprocess and biosystems engineering}, volume = {}, number = {}, pages = {}, pmid = {38441647}, issn = {1615-7605}, abstract = {Thauera is the most widely found dominant denitrifying genus in wastewater. In earlier study, MBBR augmented with a specially developed denitrifying five-membered bacterial consortium (DC5) where Thauera was found to be the most abundant and persistent genus. Therefore, to check the functional potential of Thauera in the removal of nitrate-containing wastewater in the present study Thauera sp.V14 one of the member of the consortium DC5 was used as the model organism. Thauera sp.V14 exhibited strong hydrophobicity, auto-aggregation ability, biofilm formation and denitrification ability, which indicated its robust adaptability short colonization and nitrate removal efficiency. Continuous reactor studies with Thauera sp.V14 in 10 L dMBBR showed 91% of denitrification efficiency with an initial nitrate concentration of 620 mg L[-1] within 3 h of HRT. Thus, it revealed that Thauera can be employed as an effective microorganism for nitrate removal from wastewater based on its performance in the present studies.}, } @article {pmid38441568, year = {2024}, author = {Pallós, P and Gajdács, M and Urbán, E and Szabados, Y and Szalai, K and Hevesi, L and Horváth, A and Kuklis, A and Morjaria, D and Iffat, W and Hetta, HF and Piredda, N and Donadu, MG}, title = {Characterization of antibiotic and disinfectant susceptibility in biofilm-forming Acinetobacter baumannii: A focus on environmental isolates.}, journal = {European journal of microbiology & immunology}, volume = {}, number = {}, pages = {}, doi = {10.1556/1886.2024.00014}, pmid = {38441568}, issn = {2062-509X}, abstract = {The clinical role of Acinetobacter baumannii has been highlighted in numerous infectious syndromes with a high mortality rate, due to the high prevalence of multidrug-resistant (MDR) isolates. The treatment and eradication of this pathogen is hindered by biofilm-formation, providing protection from noxious environmental factors and antimicrobials. The aim of this study was to assess the antibiotic susceptibility, antiseptic susceptibility and biofilm-forming capacity using phenotypic methods in environmental A. baumannii isolates. One hundred and fourteen (n = 114) isolates were collected, originating from various environmental sources and geographical regions. Antimicrobial susceptibility testing was carried out using the disk diffusion method, while antiseptic susceptibility was performed using the agar dilution method. Determination of biofilm-forming capacity was carried out using a microtiter-plate based method. Resistance in environmental A. baumannii isolates were highest for ciprofloxacin (64.03%, n = 73), levofloxacin (62.18%, n = 71) and trimethoprim-sulfamethoxazole (61.40%, n = 70), while lowest for colistin (1.75%, n = 2). Efflux pump overexpression was seen in 48.25% of isolates (n = 55), 49.12% (n = 56) were classified as MDR. 6.14% (n = 7), 9.65% (n = 11), 24.65% (n = 28) and 59.65% (n = 68) of isolates were non-biofilm producers, weak, medium, and strong biofilm producers, respectively. No significant differences were observed between non-MDR vs. MDR isolates regarding their distribution of biofilm-producers (P = 0.655). The MIC ranges for the tested antiseptics were as follows: benzalkonium chloride 16-128 μg mL-1, chlorhexidine digluconate 4-128 μg mL-1, formaldehyde 64-256 μg mL-1 and triclosan 2-16 μg mL-1, respectively. The conscientious use of antiseptics, together with periodic surveillance, is essential to curb the spread of these bacteria, and to maintain current infection prevention capabilities.}, } @article {pmid38438983, year = {2024}, author = {Ghazvinian, M and Asgharzadeh Marghmalek, S and Gholami, M and Amir Gholami, S and Amiri, E and Goli, HR}, title = {Antimicrobial resistance patterns, virulence genes, and biofilm formation in enterococci strains collected from different sources.}, journal = {BMC infectious diseases}, volume = {24}, number = {1}, pages = {274}, pmid = {38438983}, issn = {1471-2334}, abstract = {BACKGROUND: Currently, antibiotic-resistant strains of Enterococcus are considered to be one of the critical health challenges globally. This study aimed to investigate the antibiotic susceptibility pattern, biofilm formation capacity, and virulence genes of enterococci isolated from different sources.

METHODS: In this cross-sectional study, environmental and fecal samples were collected from the hospital environment, volunteers, and hospital staff from October 2018 to August 2019. The isolates were identified by morphological and biochemical tests (gram staining, catalase, bile resistance, esculin hydrolysis, carbohydrate fermentation, growth in 6.5% NaCl, Pyrrolidonyl arylamidase, arginine dehydrolase), and PCR for ddl gene. An antimicrobial susceptibility test was performed by the standard disk agar diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Quantitative microplate assays were used to assess biofilm production. The bacterial DNAs were extracted by alkaline lysis method and polymerase chain reaction technique was used detect the esp, ace, and efaA virulence genes.

RESULTS: Out of 145 isolates, 84 (57.9%) were identified as E. faecalis and 61 (42.1%) as E. faecium. Resistance to kanamycin and quinupristin-dalfopristin was 82.1% (69/84) and 85.7% (72/84), respectively, in E. faecalis isolates. Out of 61 E. faecalis isolates, 38 (62.4%) were resistant to kanamycin. Among the E. faecalis isolates, esp was the most dominant virulence gene (73.80%), followed by efaA, and ace, which were detected in 60.71%, and 30.95% isolates, respectively. In total, 68.27% of the strains were biofilm producers. Further, esp and efaA genes were more frequently found among E. faecalis strains with moderate and strong biofilm biomass.

CONCLUSIONS: According to the findings of our study, enterococci strains isolated from different samples possess distinctive patterns of virulence genes. The esp, ace, and efaA genes were more prevalent among E. faecalis than E. faecium. Besides, the high level antibiotic resistance of normal flora and environmental enterococci strains is alarming the researchers.}, } @article {pmid38438498, year = {2024}, author = {Hassuna, NA and Rabea, EM and Mahdi, WKM and Abdelraheem, WM}, title = {Biofilm formation and antimicrobial resistance pattern of uropathogenic E. coli ST131 isolated from children with malignant tumors.}, journal = {The Journal of antibiotics}, volume = {}, number = {}, pages = {}, pmid = {38438498}, issn = {1881-1469}, abstract = {The multidrug-resistant clone identified as Escherichia coli sequence type 131 (E. coli ST131) has spread world-wide. This study sought to ascertain the frequency and biofilm formation of E. coli ST131 isolated from children with various malignancies. A total of 60 uropathogenic E. coli (UPEC) isolates from children without cancer and 30 UPEC isolates from children with cancer were assessed in this study. The microdilution method was used to investigate the sensitivity of bacteria to antibiotics. The microtiter plate (MTP) approach was used to phenotypically assess biofilm formation. The lasR, pelA, and lecA biofilm-encoding genes were detected by PCR in biofilm-producing isolates of E. coli. Thirty-seven out of 90 E. coli isolates were found to be ST131 (41.1%), with 17 (56.7%) from cancer-affected children and 20 (33.3%) from children without cancer, respectively (P-value = 0.036). The frequency of antimicrobial resistance was higher in ST131 strains were compared to non-ST131 strains and when they were isolated from healthy children vs. those who had cancer. In contrast to non-ST131 isolates, ST131 isolates were more biofilm-producers. There was a significant difference between the percentage of biofilm producers between the 22 (100%) ST131-O16 isolates and the 13 (86.7%) ST131-O25b isolates (P-value = 0.04). Children with cancer are more likely than children without cancer to develop biofilm forming E. coli ST131, the latter having a higher profile of antibiotic resistance. Interestingly, E. coli ST131 isolates from non-cancer patients had higher levels of overall antibiotic resistance and while more E. coli ST131isolates from cancer patients formed biofilms.}, } @article {pmid38438326, year = {2024}, author = {Pinto, GR and Carvalho Filho, PC and Carvalho, RDO and Conceição, RR and Fortuna, V and Gomes-Filho, IS and Trindade, SC and Sarmento, VA}, title = {Subgingival biofilm microbiome in individuals with asthma and periodontitis: Metagenomic analysis.}, journal = {Oral diseases}, volume = {}, number = {}, pages = {}, doi = {10.1111/odi.14913}, pmid = {38438326}, issn = {1601-0825}, support = {SUS0054/2018//PPSUS (Programa Pesquisa para o SUS) / FAPESB/ ; }, abstract = {OBJECTIVE: This observational study aimed to explore the metagenomics of subgingival biofilms in individuals with varying degrees of asthma, from severe to none, to elucidate the association between the subgingival microbiome and asthma.

MATERIALS AND METHODS: Subgingival biofilm samples were collected from thirty participants at the Asthma Control Program Outpatient Clinic in Bahia (ProAR). These samples were categorized into six groups based on the severity of asthma and the presence or absence of periodontitis. We employed next-generation sequencing (Illumina MiSeq), targeting the 16S rRNA gene, to characterize the microbial communities present. Our analysis included descriptive statistics and sequencing data, evaluated using multivariate statistical methods such as the Shannon index, principal coordinate analysis, and the Bray-Curtis dissimilarity.

RESULTS: Our findings indicate a higher prevalence of periodontally detrimental bacterial genera in individuals with severe asthma and periodontitis. Additionally, individuals with asthma, but without periodontitis, exhibited a tendency toward dysbiosis, particularly in cases of severe asthma.

CONCLUSION: This research provides new insights into the composition of the subgingival microbiome in individuals with varying severities of asthma and periodontitis. The genera identified in this study underscore the need for further investigations to build upon these findings.}, } @article {pmid38437971, year = {2024}, author = {Ferreira, LSBP and Owatari, MS and de Oliveira Nuñer, AP and Lapa, KR}, title = {Biofilm viability and microbial community of non-inoculated moving bed biofilm reactor in Nile tilapia Oreochromis niloticus cultivation.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130527}, doi = {10.1016/j.biortech.2024.130527}, pmid = {38437971}, issn = {1873-2976}, abstract = {The aim of this study was to evaluate two moving bed biofilm reactors (MBBR) without nitrifying bacteria inoculation. Biofilms and viable bacterial colonies were evaluated after 124 days. MBBR bioreactors received water from Oreochromis niloticus fish farming and water quality parameters were monitored daily. Four distinct phases with different fish stocking density were established.: phase 1 (2.40 kg m[-3]), phase 2 (4.95 kg m[-3]), phase 3 (8.71 kg m[-3]) and phase 4 (12.23 kg m[-3]). The successful maturation of the bioreactors occurred around on the 100th experimental day when the nitration rate increased to 57 % in MBBR1 and 38 % in MBBR2. 105 species were identified in the biofilms, which were grouped into 65 genera, three of which were essential: Pseudomonas (21.7 %), Nitrospira (15.1 %) and Gemmobacter (11.2 %). MBBR start-up without bacterial inoculation is time-consuming, however, strengthened by important nitrifying groups.}, } @article {pmid38436775, year = {2024}, author = {Yunus, J and Wan Dagang, WRZ and Jamaluddin, H and Jemon, K and Mohamad, SE and Jonet, MA}, title = {Bacterial biofilm growth and perturbation by serine protease from Bacillus sp.}, journal = {Archives of microbiology}, volume = {206}, number = {4}, pages = {138}, pmid = {38436775}, issn = {1432-072X}, support = {FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; FRGS/1/2019/SKK11/UTM/02/1//Fundamental Research Grant Scheme/ ; }, abstract = {In nature, bacteria are ubiquitous and can be categorized as beneficial or harmless to humans, but most bacteria have one thing in common which is their ability to produce biofilm. Biofilm is encased within an extracellular polymeric substance (EPS) which provides resistance against antimicrobial agents. Protease enzymes have the potential to degrade or promote the growth of bacterial biofilms. In this study, the effects of a recombinant intracellular serine protease from Bacillus sp. (SPB) on biofilms from Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa were analyzed. SPB was purified using HisTrap HP column and concentrated using Amicon 30 ultra-centrifugal filter. SPB was added with varying enzyme activity and assay incubation period after biofilms were formed in 96-well plates. SPB was observed to have contrasting effects on different bacterial biofilms, where biofilm degradations were observed for both 7-day-old A. baumannii (37.26%) and S. aureus (71.51%) biofilms. Meanwhile, SPB promoted growth of P. aeruginosa biofilm up to 176.32%. Compatibility between protein components in S. aureus biofilm with SPB as well as a simpler membrane structure morphology led to higher biofilm degradation for S. aureus compared to A. baumannii. However, SPB promoted growth of P. aeruginosa biofilm due likely to its degrading protein factors that are responsible for biofilm detachment and dispersion, thus resulting in more multi-layered biofilm formation. Commercial protease Savinase which was used as a comparison showed degradation for all three bacterial biofilms. The results obtained are unique and will expand our understanding on the effects that bacterial proteases have toward biofilms.}, } @article {pmid38436747, year = {2024}, author = {Zheng, S and Liu, M and Han, Q and Pang, L and Cao, H}, title = {Seasonal variation and human impacts of the river biofilm bacterial communities in the Shiting River in southeastern China.}, journal = {Environmental monitoring and assessment}, volume = {196}, number = {4}, pages = {341}, pmid = {38436747}, issn = {1573-2959}, support = {52079095//National Natural Science Foundation of China/ ; 52130903//National Natural Science Foundation of China/ ; 2023YFC3206201//National Key Research and Development Program of China/ ; }, abstract = {Bacterial communities in epilithic biofilm plays an important role in biogeochemistry processes in freshwater ecosystems. Nevertheless, our understanding of the geographical and seasonal variations of the composition of bacterial communities in the biofilm of gravels on river bed is still limited. Various anthropogenic activities also influence the biofilm bacteria in gravel rivers. By taking the Shiting River in the upper Yangtze River basin in Sichuan Province as an example, we studied the geographical and seasonal variations of epilithic bacteria and the impacts of weirs and other human activities (e.g., sewage pollution). The river has experienced severe degradation since the Ms 8.0 Wenchuan Earthquake, and weirs were constructed to prevent bed erosion. We collected epilithic biofilms samples at 17 sites along ~ 30 km river reach of the Shiting River in the autumn of 2021 and the summer of 2022, respectively. We applied 16S rRNA gene high-throughput sequencing technology and Functional Annotation of Prokaryotic Taxa (FAPROTAX) to analyze the seasonal and biogeographic patterns and potential functions of the biofilm bacterial communities. The results showed that epilithic bacteria from the two surveys exhibited variation in community composition, bacterial diversity and potential functions. The bacteria samples collected in the autumn have much higher alpha diversity and richness than those collected in the summer. Bacterial richness and diversity were lower downstream of the weirs than upstream. Low diversity was observed at a sampling site influenced by sewage inflow, which contains high level of nitrogen-related chemicals.}, } @article {pmid38435686, year = {2024}, author = {Wang, R and Guragain, M and Chitlapilly Dass, S and Palanisamy, V and Bosilevac, JM}, title = {Impact of intense sanitization on environmental biofilm communities and the survival of Salmonella enterica at a beef processing plant.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1338600}, pmid = {38435686}, issn = {1664-302X}, abstract = {Salmonella enterica is a leading cause of foodborne illness in the U.S. In the meat industry, one action taken to address pathogen contamination incidence is an intense sanitization (IS) of the entire processing plant that many large processors perform annually or semiannually. However, this procedure's immediate and long-term impact on environment microbial community and pathogen colonization are unknown. Here we investigated the impact of IS procedure on environmental biofilms and the subsequent S. enterica colonization and stress tolerance. Environmental samples were collected from floor drains at various areas 1 week before, 1 week, and 4 weeks after the IS procedure at a beef plant with sporadic S. enterica prevalence. Biofilm formation by microorganisms in the drain samples without S. enterica presence was tested under processing temperature. The ability of the biofilms to recruit and/or protect a co-inoculated S. enterica strain from quaternary ammonium compound (QAC) treatment was determined. The community structure of each drain sample was elucidated through 16S rRNA amplicon community sequencing. Post-IS samples collected from 8 drains formed significantly stronger biofilms than the respective pre-IS samples. S. enterica colonization was not different between the pre- and post-IS biofilms at all drain locations. S. enterica survival in QAC-treated pre- and post-IS mixed biofilms varied depending upon the drain location but a higher survival was associated with a stronger biofilm matrix. The 16S rRNA amplicon gene community sequencing results exhibited a decrease in community diversity 1 week after IS treatment but followed by a significant increase 4 weeks after the treatment. The IS procedure also significantly altered the community composition and the higher presence of certain species in the post-IS community may be associated with the stronger mixed biofilm formation and Salmonella tolerance. Our study suggested that the IS procedure might disrupt the existing environmental microbial community and alter the natural population composition, which might lead to unintended consequences as a result of a lack of competition within the multispecies mixture. The survival and recruitment of species with high colonizing capability to the post-IS community may play crucial roles in shaping the ensuing ecological dynamics.}, } @article {pmid38435376, year = {2024}, author = {Hussain, B and Simm, R and Bueno, J and Giannettou, S and Naemi, AO and Lyngstadaas, SP and Haugen, HJ}, title = {Biofouling on titanium implants: a novel formulation of poloxamer and peroxide for in situ removal of pellicle and multi-species oral biofilm.}, journal = {Regenerative biomaterials}, volume = {11}, number = {}, pages = {rbae014}, pmid = {38435376}, issn = {2056-3418}, abstract = {Eradicating biofouling from implant surfaces is essential in treating peri-implant infections, as it directly addresses the microbial source for infection and inflammation around dental implants. This controlled laboratory study examines the effectiveness of the four commercially available debridement solutions '(EDTA (Prefgel[®]), NaOCl (Perisolv[®]), H2O2 (Sigma-Aldrich) and Chlorhexidine (GUM[®] Paroex[®]))' in removing the acquired pellicle, preventing pellicle re-formation and removing of a multi-species oral biofilm growing on a titanium implant surface, and compare the results with the effect of a novel formulation of a peroxide-activated 'Poloxamer gel (Nubone[®] Clean)'. Evaluation of pellicle removal and re-formation was conducted using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy to assess the surface morphology, elemental composition and chemical surface composition. Hydrophilicity was assessed through contact angle measurements. The multi-species biofilm model included Streptococcus oralis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, reflecting the natural oral microbiome's complexity. Biofilm biomass was quantified using safranin staining, biofilm viability was evaluated using confocal laser scanning microscopy, and SEM was used for morphological analyses of the biofilm. Results indicated that while no single agent completely eradicated the biofilm, the 'Poloxamer gel' activated with 'H2O2' exhibited promising results. It minimized re-contamination of the pellicle by significantly lowering the contact angle, indicating enhanced hydrophilicity. This combination also showed a notable reduction in carbon contaminants, suggesting the effective removal of organic residues from the titanium surface, in addition to effectively reducing viable bacterial counts. In conclusion, the 'Poloxamer gel + H2O2' combination emerged as a promising chemical decontamination strategy for peri-implant diseases. It underlines the importance of tailoring treatment methods to the unique microbial challenges in peri-implant diseases and the necessity of combining chemical decontaminating strategies with established mechanical cleaning procedures for optimal management of peri-implant diseases.}, } @article {pmid38435305, year = {2024}, author = {Abdelhamid, AG and Yousef, AE}, title = {Untargeted metabolomics unveiled the role of butanoate metabolism in the development of Pseudomonas aeruginosa hypoxic biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {14}, number = {}, pages = {1346813}, pmid = {38435305}, issn = {2235-2988}, abstract = {Pseudomonas aeruginosa is a versatile opportunistic pathogen which causes a variety of acute and chronic human infections, some of which are associated with the biofilm phenotype of the pathogen. We hypothesize that defining the intracellular metabolome of biofilm cells, compared to that of planktonic cells, will elucidate the metabolic pathways and biomarkers indicative of biofilm inception. Disc-shaped stainless-steel coupons (12.7 mm diameter) were employed as a surface for static biofilm establishment. Each disc was immersed in a well, of a 24-well microtiter plate, containing a 1-mL Lysogeny broth (LB) suspension of P. aeruginosa ATCC 9027, a strain known for its biofilm prolificacy. This setup underwent oxygen-depleted incubation at 37°C for 24 hours to yield hypoxic biofilms and the co-existing static planktonic cells. In parallel, another planktonic phenotype of ATCC 9027 was produced in LB under shaking (200 rpm) incubation at 37°C for 24 hours. Planktonic and biofilm cells were harvested, and the intracellular metabolites were subjected to global untargeted metabolomic analysis using LC-MS technology, where small metabolites (below 1.5 kDa) were selected. Data analysis showed the presence of 324 metabolites that differed (p < 0.05) in abundance between planktonic and biofilm cells, whereas 70 metabolites did not vary between these phenotypes (p > 0.05). Correlation, principal components, and partial least square discriminant analyses proved that the biofilm metabolome is distinctly clustered away from that of the two planktonic phenotypes. Based on the functional enrichment analysis, arginine and proline metabolism were enriched in planktonic cells, but butanoate metabolism was enriched in biofilm cells. Key differential metabolites within the butanoate pathway included acetoacetate, 2,3-butandiol, diacetyl, and acetoin, which were highly upregulated in the biofilm compared to the planktonic cells. Exogenous supplementation of acetoin (2 mM), a critical metabolite in butanoate metabolism, augmented biofilm mass, increased the structural integrity and thickness of the biofilm, and maintained the intracellular redox potential by balancing NADH/NAD[+] ratio. In conclusion, P. aeruginosa hypoxic biofilm has a specialized metabolic landscape, and butanoate pathway is a metabolic preference and possibly required for promoting planktonic cells to the biofilm state. The butanoate pathway metabolites, particularly acetoin, could serve as markers for biofilm development.}, } @article {pmid38434581, year = {2024}, author = {Kaliniak, S and Fiedoruk, K and Spałek, J and Piktel, E and Durnaś, B and Góźdź, S and Bucki, R and Okła, S}, title = {Remodeling of Paranasal Sinuses Mucosa Functions in Response to Biofilm-Induced Inflammation.}, journal = {Journal of inflammation research}, volume = {17}, number = {}, pages = {1295-1323}, doi = {10.2147/JIR.S443420}, pmid = {38434581}, issn = {1178-7031}, abstract = {Rhinosinusitis (RS) is an acute (ARS) or chronic (CRS) inflammatory disease of the nasal and paranasal sinus mucosa. CRS is a heterogeneous condition characterized by distinct inflammatory patterns (endotypes) and phenotypes associated with the presence (CRSwNP) or absence (CRSsNP) of nasal polyps. Mucosal barrier and mucociliary clearance dysfunction, inflammatory cell infiltration, mucus hypersecretion, and tissue remodeling are the hallmarks of CRS. However, the underlying factors, their priority, and the mechanisms of inflammatory responses remain unclear. Several hypotheses have been proposed that link CRS etiology and pathogenesis with host (eg, "immune barrier") and exogenous factors (eg, bacterial/fungal pathogens, dysbiotic microbiota/biofilms, or staphylococcal superantigens). The abnormal interplay between these factors is likely central to the pathophysiology of CRS by triggering compensatory immune responses. Here, we discuss the role of the sinonasal microbiota in CRS and its biofilms in the context of mucosal zinc (Zn) deficiency, serving as a possible unifying link between five host and "bacterial" hypotheses of CRS that lead to sinus mucosa remodeling. To date, no clear correlation between sinonasal microbiota and CRS has been established. However, the predominance of Corynebacteria and Staphylococci and their interspecies relationships likely play a vital role in the formation of the CRS-associated microbiota. Zn-mediated "nutritional immunity", exerted via calprotectin, alongside the dysregulation of Zn-dependent cellular processes, could be a crucial microbiota-shaping factor in CRS. Similar to cystic fibrosis (CF), the role of SPLUNC1-mediated regulation of mucus volume and pH in CRS has been considered. We complement the biofilms' "mechanistic" and "mucin" hypotheses behind CRS pathogenesis with the "structural" one - associated with bacterial "corncob" structures. Finally, microbiota restoration approaches for CRS prevention and treatment are reviewed, including pre- and probiotics, as well as Nasal Microbiota Transplantation (NMT).}, } @article {pmid38432208, year = {2024}, author = {Araujo, TT and Carvalho, TS and Dionizio, A and Rodrigues, CMVBF and Henrique-Silva, F and Chiaratti, M and Santos, A and Alves, L and Ferro, M and Buzalaf, MAR}, title = {Acquired Pellicle and Biofilm engineering by rinsing with hemoglobin solution.}, journal = {Caries research}, volume = {}, number = {}, pages = {}, doi = {10.1159/000537976}, pmid = {38432208}, issn = {1421-976X}, abstract = {INTRODUCTION: The identification of acid-resistant proteins, including hemoglobin (Hb), within the acquired enamel pellicle (AEP) led to the proposition of the "acquired pellicle engineering" concept, which involves the modification of the AEP by incorporating specific proteins, presenting a novel strategy to prevent dental demineralization.

OBJECTIVE: Combining in vivo and in vitro proof-of-concept protocols we sought to reveal the impact of AEP engineering with Hb protein on the biofilm microbiome and enamel demineralization.

METHODS: In the in vivo studies, 10-volunteers, in 2 independent experiments, rinsed (10mL,1min) with: deionized water-negative control or 1.0mg/mL Hb. The AEP and biofilm formed along 2 or 3h, respectively, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics and biofilm by 16S-rRNA Next-Generation-Sequencing (NGS). In vitro study, a microcosm biofilm protocol was employed. Seventy-two bovine enamel specimens were treated with: 1)Phosphate-Buffered Solution-PBS, 2)0.12% Chlorhexidine, 3)500ppm NaF; 4)1.0mg/mL Hb; 5)2.0mg/mL Hb, and 6)4.0mg/mL Hb. The biofilm was cultivated for 5-days. Resazurin, colony-forming-units(CFU) and Transversal Microradiography(TMR) were performed.

RESULTS: Proteomics and NGS analysis revealed that Hb increased proteins with antioxidant, antimicrobial, acid-resistance, hydroxyapatite-affinity, calcium-binding properties and showed a reduction in oral pathogenic bacteria. In vitro experiments demonstrated that the lowest Hb concentration was the most effective in reducing bacterial activity, CFU and enamel demineralization compared to PBS.

CONCLUSION: These findings suggest that Hb could be incorporated into anticaries dental products to modify the oral microbiome and control caries, highlighting its potential for AEP and biofilm microbiome engineering.}, } @article {pmid38431509, year = {2024}, author = {Topçu, S and Tekçe, N and Kopuz, D and Özcelik, EY and Kolaylı, F and Tuncer, S and Demirci, M}, title = {Effect of surface roughness and biofilm formation on the color properties of resin-infiltrated ceramic and lithium disilicate glass-ceramic CAD-CAM materials.}, journal = {The Journal of prosthetic dentistry}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.prosdent.2024.02.005}, pmid = {38431509}, issn = {1097-6841}, abstract = {STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacturing (CAD-CAM) materials have become popular for dental restorations; however, which materials should be preferred in terms of surface properties after biofilm formation is unclear.

PURPOSE: The purpose of this in vitro study was to investigate the effect of biofilm formation on the discoloration properties of resin-infiltrated ceramic and glass ceramic CAD-CAM materials and human teeth and to examine the effect of the brushing procedure on color change.

MATERIAL AND METHODS: One hundred and six 2-mm-thick specimens were prepared from IPS e.max CAD and Cerasmart, and a total of 53 intact human teeth were used. Five specimens from each group were used to measure the amount of live biomass in the biofilm. The remaining 48 specimens in each group were divided into 4 subgroups: kept in distilled water without the formation of dental biofilm (DW), kept in tea without the formation of dental biofilm (T), kept in distilled water after the formation of dental biofilm (DWB), and kept in tea after the formation of dental biofilm (TB) (n=12). After finishing and polishing the materials, initial color measurements were made using a spectrophotometer, and surface roughness measurements were made using noncontact profilometer. After creating a biofilm layer in DWB and TB, all specimens were kept in their solutions at 37 °C for 24 hours, and the color measurements were repeated. After the biofilm layer had been removed by brushing, a third color measurement was made. The data were statistically analyzed with one-way analysis of variance (ANOVA) and two-way ANOVA (α=.05).

RESULTS: The lowest roughness value was observed in Cerasmart. Tooth-IPS e.max CAD gave similar results. The Cerasmart material had the most viable biomass, whereas the IPS e.max CAD material had the least. TB had the highest ΔE1 value for all materials and DW had the lowest (P<.05). The brushing procedure caused the materials to return to their initial colors or reduce the color change in most groups.

CONCLUSIONS: The presence of biofilm on CAD-CAM materials immersed in distilled water caused an unacceptable degree of discoloration (ΔE>1.8), and immersion in tea led to greater color change. The adhesion of biofilm to restorative dental materials plays an important role in the coloring of these dental materials.}, } @article {pmid38431335, year = {2024}, author = {Zhou, G and Liu, Y and Dong, P and Mao, Y and Zhu, L and Luo, X and Zhang, Y}, title = {Airborne signals of Pseudomonas fluorescens modulate swimming motility and biofilm formation of Listeria monocytogenes in a contactless coculture system.}, journal = {Food microbiology}, volume = {120}, number = {}, pages = {104494}, doi = {10.1016/j.fm.2024.104494}, pmid = {38431335}, issn = {1095-9998}, abstract = {Bacterial volatile compounds (BVCs) facilitate interspecies communication in socio-microbiology across physical barriers, thereby influencing interactions between diverse species. The impact of BVCs emitted from Pseudomonas on the biofilm formation characteristics of Listeria monocytogenes within the same ecological niche has been scarcely investigated under practical conditions of food processing. The objective of this study was to explore the motility and biofilm formation characteristics of L. monocytogenes under the impact of Pseudomonas BVCs. It was revealed that BVCs of P. fluorescens, P. lundensis, and P. fragi significantly promoted swimming motility of L. monocytogenes (P < 0.05). As evidenced by crystal violet staining, the L. monocytogenes biofilms reached a maximum OD570 value of approximately 3.78 at 4 d, which was 0.65 units markedly higher than that of the control group (P < 0.05). Despite a decrease in adherent cells of L. monocytogenes biofilms among the BVCs groups, there was a remarkable increase in the abundance of extracellular polysaccharides and proteins with 3.58 and 4.90 μg/cm[2], respectively (P < 0.05), contributing to more compact matrix architectures, which suggested that the BVCs of P. fluorescens enhanced L. monocytogenes biofilm formation through promoting the secretion of extracellular polymers. Moreover, the prominent up-regulated expression of virulence genes further revealed the positive regulation of L. monocytogenes under the influence of BVCs. Additionally, the presence of BVCs significantly elevated the pH and TVB-N levels in both the swimming medium and biofilm broth, thereby exhibiting a strong positive correlation with increased motility and biofilm formation of L. monocytogenes. It highlighted the crucial signaling regulatory role of BVCs in bacterial interactions, while also emphasizing the potential food safety risk associated with the hitchhiking behavior of L. monocytogenes, thereby shedding light on advancements in control strategies for food processing.}, } @article {pmid38431332, year = {2024}, author = {Li, Y and Wangjiang, T and Sun, Z and Shi, L and Chen, S and Chen, L and Guo, X and Wu, W and Xiong, G and Wang, L}, title = {Inhibition mechanism of crude lipopeptide from Bacillus subtilis against Aeromonas veronii growth, biofilm formation, and spoilage of channel catfish flesh.}, journal = {Food microbiology}, volume = {120}, number = {}, pages = {104489}, doi = {10.1016/j.fm.2024.104489}, pmid = {38431332}, issn = {1095-9998}, abstract = {Aeromonas veronii is associated with food spoilage and some human diseases, such as diarrhea, gastroenteritis, hemorrhagic septicemia or asymptomatic and even death. This research investigated the mechanism of the growth, biofilm formation, virulence, stress resistance, and spoilage potential of Bacillus subtilis lipopeptide against Aeromonas veronii. Lipopeptides suppressed the transmembrane transport of Aeromonas veronii by changing the cell membrane's permeability, the structure of membrane proteins, and Na[+]/K[+]-ATPase. Lipopeptide significantly reduced the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) by 86.03% and 56.12%, respectively, ultimately slowing Aeromonas veronii growth. Lipopeptides also restrained biofilm formation by inhibiting Aeromonas veronii motivation and extracellular polysaccharide secretion. Lipopeptides downregulated gene transcriptional levels related to the virulence and stress tolerance of Aeromonas veronii. Furthermore, lipopeptides treatment resulted in a considerable decrease in the extracellular protease activity of Aeromonas veronii, which restrained the decomposing of channel catfish flesh. This research provides new insights into lipopeptides for controlling Aeromonas veronii and improving food safety.}, } @article {pmid38431313, year = {2024}, author = {Qin, M and Han, S and Chen, M and Li, P and Wang, Y and Niu, W and Gao, C and Wang, H and Li, Y}, title = {Biofilm formation of Hafnia paralvei induced by c-di-GMP through facilitating bcsB gene expression promotes spoilage of Yellow River carp (Cyprinus carpio).}, journal = {Food microbiology}, volume = {120}, number = {}, pages = {104482}, doi = {10.1016/j.fm.2024.104482}, pmid = {38431313}, issn = {1095-9998}, abstract = {Hafnia paralvei, a Gram-negative foodborne pathogen, is found ubiquitously in various aquatic animals and seafoods, which can form biofilm as a dominant virulence factor that contributes to its pathogenesis. However, the biofilm formation mechanism of H. paralvei and its effect on food spoilage has not been fully characterized. Here we show that biofilm formation, is regulated by c-di-GMP which mediated by bcsB, can increase the spoilage ability of H. paralvei. We found that GTP was added exogenously to enhance the synthesis of c-di-GMP, which further promoted biofilm formation. The gene dgcC, one of 11 genes encoding GGDEF domain-containing proteins in H. paralvei, was significantly upregulated with GTP as substrate. The upregulation of dgcC contributes to a significant increase of c-di-GMP and the formation of biofilm. In addition, the overexpression of dgcC induced upregulation of bcsB, a reported effector protein encoding gene, which was further demonstrated that overexpression of bcsB can encourage the synthesis of bacterial cellulose and biofilm formation. The effect of biofilm formation induced by c-di-GMP on spoilage of Yellow River carp (Cyprinus carpio) was evaluated by sensory evaluation, the total viable count, and the total volatile basic nitrogen, which showed that biofilm formation can significantly increase the spoilage ability of H. paralvei on C. carpio. Our findings provide the regulation of c-di-GMP on expression of bcsB, that can contribute to biofilm formation and spoilage ability of H. paralvei, which is favor to understanding the pathogenesis of Hafnia paralvei and its role in food spoilage.}, } @article {pmid38431311, year = {2024}, author = {Gaillac, A and Gourin, C and Dubreil, L and Briandet, R and Prévost, H and Jaffrès, E}, title = {Biofilm formation of the food spoiler Brochothrix thermosphacta on different industrial surface materials using a biofilm reactor.}, journal = {Food microbiology}, volume = {120}, number = {}, pages = {104457}, doi = {10.1016/j.fm.2023.104457}, pmid = {38431311}, issn = {1095-9998}, abstract = {Brochothrix thermosphacta is considered as a major food spoiler bacteria. This study evaluates biofilm formation by B. thermosphacta CD337(2) - a strong biofilm producer strain - on three food industry materials (polycarbonate (PC), polystyrene (PS), and stainless steel (SS)). Biofilms were continuously grown under flow at 25 °C in BHI broth in a modified CDC biofilm reactor. Bacterial cells were enumerated by plate counting, and biofilm spatial organization was deciphered by combining confocal laser scanning microscopy and image analysis. The biofilms had the same growth kinetics on all three materials and reach 8log CFU/cm[2] as maximal concentration. Highly structured biofilms were observed on PC and PS, but less structured ones on SS. This difference was confirmed by structural quantification analysis using the image analysis software tool BiofilmQ. Biofilm on SS show less roughness, density, thickness and volume. The biofilm 3D structure seemed to be related to the coupon topography and roughness. The materials used in this study do not affect biofilm growth. However, their roughness and topography affect the biofilm architecture, which could influence biofilm behaviour.}, } @article {pmid38430875, year = {2024}, author = {Liu, W and Li, J and Lu, H and Peng, Y}, title = {Sponge iron strengthens the activity of anammox biofilm under low nitrogen conditions in a two-stage fixed-bed biofilm reactor.}, journal = {Journal of environmental management}, volume = {355}, number = {}, pages = {120194}, doi = {10.1016/j.jenvman.2024.120194}, pmid = {38430875}, issn = {1095-8630}, abstract = {Strengthening the activity competitiveness of anaerobic ammonium oxidation (anammox) bacteria (AnAOB) under low nitrogen conditions is indispensable for mainstream anammox application. This study demonstrates that sponge iron addition (42.8 g/L) effectively increased apparent AnAOB activity and extracellular polymeric substance (EPS) production of low load anammox biofilms cultivated under low (influent of 60 mg N/L) and even ultra-low (influent of 10 mg N/L) nitrogen conditions. In-situ batch tests showed that after sponge iron addition the specific AnAOB activity in the low and ultra-low nitrogen systems further increased to 1.18 and 0.47 mmol/g VSS/h, respectively, with an apparent growth rate for AnAOB of 0.011 ± 0.001 d[-1] and 0.004 ± 0.001 d[-1], respectively. The averaged EPS concentration of anammox biofilm in both low (from 35.84 to 71.05 mg/g VSS) and ultra-low (from 44.14 to 57.59 mg/g VSS) nitrogen systems increased significantly, while a higher EPS protein/polysaccharide ratio, which was positively correlated with AnAOB activity, was observed in the low nitrogen system (3.54 ± 0.34) than that in the ultra-low nitrogen system (1.82 ± 0.10). In addition, Candidatus Brocadia was detected as dominant AnAOB in the anammox biofilm under the low (12.2 %) and ultra-low (24.7 %) nitrogen condition. Notably, the genus Streptomyces (26.3 %), capable for funge-like codenitrification, increased unexpectedly in the low nitrogen system, but not affecting the nitrogen removal performance. Therefore, using sponge iron to strengthen AnAOB activity under low nitrogen conditions is feasible, providing support for mainstream anammox applications.}, } @article {pmid38429695, year = {2024}, author = {Cyris, M and Holtmann, P and Dörfer, CE and Holtmann, L and Kern, M and Graetz, C}, title = {Long-term effect of simulated five years professional mechanical biofilm removal on the luting gap of ceramic restorations.}, journal = {BMC oral health}, volume = {24}, number = {1}, pages = {291}, pmid = {38429695}, issn = {1472-6831}, mesh = {Humans ; *Composite Resins ; Powders ; Surface Properties ; *Ceramics ; Glass Ionomer Cements ; }, abstract = {BACKGROUND: Achieving sufficient professional mechanical biofilm removal (PMPR) can be challenging in supportive periodontal therapy (SPT), particularly in patients with prosthetic restorations. This experimental study aimed to simulate five years of SPT with periodic PMPR near the luting gap of ceramic restorations using a rubber cup with polishing paste (RCP), air polishing with two different low-abrasive powders (LAPA-1: glycine powder, LAPA-2: erythritol powder), and non-professional mechanical cleaning (control group) to measure the extent of volume loss in the luting gap after baseline (∆V = Vbaseline-V1-5; in µm[3]).

METHODS: Two operators randomly performed PMPR ten times for thirty seconds on one of four sides of 30 crown replicas fixed with glass-ionomer cement (CGIZ: n = 15) or adhesive bonding (CAB: n = 15). The replicas were separated in a template during PMPR, and afterward, cleaned for five seconds per side with a sonic brush under flowing water. The artificial aging process between two PMPRs simulated a 5-year SPT with two PMPRs per year. Profilometric measurements were performed at baseline and after each second PMPR to obtain the mean change of ∆V. The statistical evaluation of the data was carried out using nonparametric tests with Bonferroni correction applied for multiple tests.

RESULTS: Ninety-six out of 120 sides could be included in the analysis. PMPR methods showed a loss of substance in the luting gap with a ∆V (mean(standard deviation)) of -4.35 × 10[6](4.8 × 10[6])µm[3] versus 8.79 × 10[4](1.05 × 10[6])µm[3] for control at V5 (p ≤ 0.001). No significant differences of ∆V1-5 values could be identified in the control (p > 0.05), whereat all PMPRs showed a significant increasing loss of substance per simulated year (p ≤ 0.001). Intergroup comparison identified LAPA-1 as having the highest significant loss of substance determined on CAB (∆V: -1.05 × 10[7] (7,2 × 10[6]) µm[3]), followed by LAPA-2 on CAB (∆V: -6.29 × 10[6] (4,24 × 10[6]) µm[3]), LAPA-1 on CGIZ (∆V: -4.15 × 10[6] (3,25 × 10[6]) µm[3]), LAPA-2 on CGIZ (∆V: -3.0 × 10[6] (2,23 × 10[6]) µm[3]), RCP on CAB (∆V: -1.86 × 10[6] (2,23 × 10[6]) µm[3]) and CGIZ (∆V: -1.2 × 10[6] (1,31 × 10[6]) µm[3]; p ≤ 0.001)).

CONCLUSIONS: Within study limitations, all PMPRs caused a significantly higher loss of substance in the luting gap versus control without professional intervention, with the highest values in the CAB group for LAPA-1, LAPA-2 and RCP. Similar findings were observed for CGIZ, although the loss values were lower.}, } @article {pmid38429597, year = {2024}, author = {Li, J and Zhang, Q and Zhao, J and Zhang, H and Chen, W}, title = {Lactobacillus-derived components for inhibiting biofilm formation in the food industry.}, journal = {World journal of microbiology & biotechnology}, volume = {40}, number = {4}, pages = {117}, pmid = {38429597}, issn = {1573-0972}, support = {32072197//National Natural Science Foundation of China/ ; }, mesh = {*Lactobacillus/metabolism ; Food Industry ; Food-Processing Industry ; *Bacteriocins/pharmacology/metabolism ; Biofilms ; }, abstract = {Biofilm, a microbial community formed by especially pathogenic and spoilage bacterial species, is a critical problem in the food industries. It is an important cause of continued contamination by foodborne pathogenic bacteria. Therefore, removing biofilm is the key to solving the high pollution caused by foodborne pathogenic bacteria in the food industry. Lactobacillus, a commonly recognized probiotic that is healthy for consumer, have been proven useful for isolating the potential biofilm inhibitors. However, the addition of surface components and metabolites of Lactobacillus is not a current widely adopted biofilm control strategy at present. This review focuses on the effects and preliminary mechanism of action on biofilm inhibition of Lactobacillus-derived components including lipoteichoic acid, exopolysaccharides, bacteriocins, secreted protein, organic acids and some new identified molecules. Further, the review discusses several modern biofilm identification techniques and particularly interesting new technology of biofilm inhibition molecules. These molecules exhibit stronger inhibition of biofilm formation, playing a pivotal role in food preservation and storage. Overall, this review article discusses the application of biofilm inhibitors produced by Lactobacillus, which would greatly aid efforts to eradicate undesirable bacteria from environment in the food industries.}, } @article {pmid38429317, year = {2024}, author = {Tan, X and Huang, Y and Rana, A and Singh, N and Abbey, TC and Chen, H and Toth, PT and Bulman, ZP}, title = {Optimization of an in vitro Pseudomonas aeruginosa Biofilm Model to Examine Antibiotic Pharmacodynamics at the Air-Liquid Interface.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {16}, pmid = {38429317}, issn = {2055-5008}, support = {R01AI173064//U.S. Department of Health & Human Services | NIH | Office of Extramural Research, National Institutes of Health (OER)/ ; }, mesh = {Humans ; Anti-Bacterial Agents ; Pseudomonas aeruginosa ; Polymyxin B/pharmacology ; Tobramycin/pharmacology ; *Pseudomonas Infections/drug therapy ; Biofilms ; *Respiratory Tract Infections ; }, abstract = {Pseudomonas aeruginosa is an important cause of lower respiratory tract infections, such as ventilator-associated bacterial pneumonia (VABP). Using inhaled antibiotics to treat VABP can achieve high drug concentrations at the infection site while minimizing systemic toxicities. Despite the theoretical advantages, clinical trials have failed to show a benefit for inhaled antibiotic therapy in treating VABP. A potential reason for this discordance is the presence of biofilm-embedded bacteria in lower respiratory tract infections. Drug selection and dosing are often based on data from bacteria grown planktonically. In the present study, an in vitro air-liquid interface pharmacokinetic/pharmacodynamic biofilm model was optimized to evaluate the activity of simulated epithelial lining fluid exposures of inhaled and intravenous doses of polymyxin B and tobramycin against two P. aeruginosa strains. Antibiotic activity was also determined against the P. aeruginosa strains grown planktonically. Our study revealed that inhaled antibiotic exposures were more active than their intravenous counterparts across biofilm and planktonic populations. Inhaled exposures of polymyxin B and tobramycin exhibited comparable activity against planktonic P. aeruginosa. Although inhaled polymyxin B exposures were initially more active against P. aeruginosa biofilms (through 6 h), tobramycin was more active by the end of the experiment (48 h). Together, these data slightly favor the use of inhaled tobramycin for VABP caused by biofilm-forming P. aeruginosa that are not resistant to either antibiotic. The optimized in vitro air-liquid interface pharmacokinetic/pharmacodynamic biofilm model may be beneficial for the development of novel anti-biofilm agents or to optimize antibiotic dosing for infections such as VABP.}, } @article {pmid38429168, year = {2024}, author = {Volk, M and Molan, K and Šavli, D and Terlep, S and Levičnik-Höfferle, Š and Gašpirc, B and Lukač, M and Jezeršek, M and Stopar, D}, title = {Biofilm removal from Difficult-to-Reach places via secondary cavitation within a constrained geometry mimicking a Periodontal/Peri-Implant pocket.}, journal = {Ultrasonics sonochemistry}, volume = {}, number = {}, pages = {106832}, doi = {10.1016/j.ultsonch.2024.106832}, pmid = {38429168}, issn = {1873-2828}, abstract = {Biofilm removal from the apical region of the periodontal or peri-implant pocket, which is very difficult to achieve with mechanical instruments, is a major unresolved issue in dentistry. Here, we propose the use of photoacoustically induced streaming and secondary cavitation to achieve superior cleaning efficacy in the apical region of the periodontal and peri-implant pocket. We have used a prefabricated narrow wedge system that mimics the consistency of periodontal and peri-implant pockets of both healthy and severely inflamed tissue. We studied the effect of single-pulse modality Er:YAG on Pseudomonas aeruginosa biofilm removal. We used different laser energies, fiber-tip positions, and laser treatment durations. The cleaning process was monitored in real-time with a high-speed camera after each individual laser pulse application. The obtained results suggest that biofilm cleaning efficacy in a difficult-to-reach place in healthy model tissue is directly related to the onset of secondary cavitation bubble formation, which correlates with a significant improvement of biofilm removal from the apical region of the periodontal or peri-implant pocket. In comparison to the healthy tissue model, the laser energy in inflamed tissue model had to be increased to obtain comparable biofilm cleaning efficacy. The advantage of photoacoustic cavitation compared to other methods is that laser-induced cavitation can trigger secondary cavitation at large distances from the point of laser application, which in principle allows biofilm removal at distant locations not reachable with a laser fiber tip or other mechanical instruments.}, } @article {pmid38428183, year = {2024}, author = {Zheng, Z and Wang, X and Zhang, W and Wang, L and Lyu, H and Tang, J}, title = {Regulation of ARGs abundance by biofilm colonization on microplastics under selective pressure of antibiotics in river water environment.}, journal = {Journal of environmental management}, volume = {355}, number = {}, pages = {120402}, doi = {10.1016/j.jenvman.2024.120402}, pmid = {38428183}, issn = {1095-8630}, abstract = {Interactions of microplastics (MPs) biofilm with antibiotic resistance genes (ARGs) and antibiotics in aquatic environments have made microplastic biofilm an issue of keen scholarly interest. The process of biofilm formation and the degree of ARGs enrichment in the presence of antibiotic-selective pressure and the impact on the microbial community need to be further investigated. In this paper, the selective pressure of ciprofloxacin (CIP) and illumination conditions were investigated to affect the physicochemical properties, biomass, and extracellular polymer secretion of polyvinyl chloride (PVC) microplastic biofilm. In addition, relative copy numbers of nine ARGs were analyzed by real-time quantitative polymerase chain reaction (qPCR). In the presence of CIP, microorganisms in the water and microplastic biofilm were more inclined to carry associated ARGs (2-3 times higher), which had a contributing effect on ARGs enrichment. The process of pre-microplastic biofilm formation might have an inhibitory effect on ARGs (total relative abundance up to 0.151) transfer and proliferation compared to the surrounding water (total relative abundance up to 0.488). However, in the presence of CIP stress, microplastic biofilm maintained the abundance of ARGs (from 0.151 to 0.149) better compared to the surrounding water (from 0.488 to 0.386). Therefore, microplastic biofilm act as abundance buffer island of ARGs stabilizing the concentration of ARGs. In addition, high-throughput analyses showed the presence of antibiotic-resistant (Pseudomonas) and pathogenic (Vibrio) microorganisms in biofilm under different conditions. The above research deepens our understanding of ARGs enrichment in biofilm and provides important insights into the ecological risks of interactions between ARGs, antibiotics, and microplastic biofilm.}, } @article {pmid38426732, year = {2024}, author = {Silva-Bea, S and García-Meniño, I and Rey, S and Romero, M and Fernández, J and Hammerl, JA and Mora, A and Otero, A}, title = {Draft genome sequence of Klebsiella pneumoniae KLEB-33: a convergent biofilm hyperforming multiresistant strain belonging to the emerging ST16 lineage harboring multiple hypervirulence genes.}, journal = {Microbiology resource announcements}, volume = {}, number = {}, pages = {e0119223}, doi = {10.1128/mra.01192-23}, pmid = {38426732}, issn = {2576-098X}, abstract = {The emergence of convergent Klebsiella pneumoniae strains showing multiresistance, characteristic of nosocomial pathotypes and hypervirulent traits typical of community-acquired isolates, makes them important models for studying K. pneumoniae pathogenesis. Here, we describe the convergent, multidrug-resistant KLEB-33 strain harboring several hypervirulence genes and make its genome available to the scientific community.}, } @article {pmid38426051, year = {2024}, author = {Kurbatfinski, N and Kramer, CN and Goodman, SD and Bakaletz, LO}, title = {Corrigendum: ESKAPEE pathogens newly released from biofilm residence by a targeted monoclonal are sensitized to killing by traditional antibiotics.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1382491}, doi = {10.3389/fmicb.2024.1382491}, pmid = {38426051}, issn = {1664-302X}, abstract = {[This corrects the article DOI: 10.3389/fmicb.2023.1202215.].}, } @article {pmid38425932, year = {2024}, author = {Wang, S and Liu, S and Cao, S and Bao, Y and Wang, L and He, ZE and Li, J and Zhou, Y and Lv, M}, title = {Engineering Bacterial Biofilm Development and Structure via Regulation of Silver Nanoparticle Density in Graphene Oxide Composite Coating.}, journal = {JACS Au}, volume = {4}, number = {2}, pages = {855-864}, pmid = {38425932}, issn = {2691-3704}, abstract = {Graphene-based composites have shown significant potential in the treatment of biofilm infections in clinical settings due to their exceptional antimicrobial properties and specific mechanisms. Nevertheless, a comprehensive understanding of the influence exerted by nanoparticles embedded in the composites on the development and structure of biofilms is still lacking. Here, we fabricate different graphene oxide-silver nanoparticle (GAg) composite-modified substrates (GAgS) with varying densities of silver nanoparticles (AgNPs) and investigate their effects on planktonic bacterial adhesion, subsequent biofilm formation, and mature biofilm structure. Our findings indicate that the initial attachment of Pseudomonas aeruginosa cells during biofilm formation is determined by the density of AgNPs on the GAgS surface. In contrast, the subsequent transition from adherent bacteria to the biofilm is determined by GAgS's synergistic antimicrobial effect. There exists a threshold for the inhibitory performance of GAgS, where the 20 μg/cm[2] GAg composite completely prevents biofilm formation; below this concentration, GAgS delays the development of the biofilm and causes structural changes in the mature biofilm with enhanced bacterial growth and increased production of extracellular polymeric substance. More importantly, GAgS have minimal impact on mammalian cell morphology and proliferation while not inducing hemolysis in red blood cells. These results suggest that GAg composites hold promise as a therapeutic approach for addressing medical devices and implant-associated biofilm infections.}, } @article {pmid38425782, year = {2024}, author = {Sankar, S and Kodiveri Muthukaliannan, G}, title = {Deciphering the crosstalk between inflammation and biofilm in chronic wound healing: Phytocompounds loaded bionanomaterials as therapeutics.}, journal = {Saudi journal of biological sciences}, volume = {31}, number = {4}, pages = {103963}, doi = {10.1016/j.sjbs.2024.103963}, pmid = {38425782}, issn = {1319-562X}, abstract = {In terms of the economics and public health, chronic wounds exert a significant detrimental impact on the health care system. Bacterial infections, which cause the formation of highly resistant biofilms that elude standard antibiotics, are the main cause of chronic, non-healing wounds. Numerous studies have shown that phytochemicals are effective in treating a variety of diseases, and traditional medicinal plants often include important chemical groups such alkaloids, phenolics, tannins, terpenes, steroids, flavonoids, glycosides, and fatty acids. These substances are essential for scavenging free radicals which helps in reducing inflammation, fending off infections, and hastening the healing of wounds. Bacterial species can survive in chronic wound conditions because biofilms employ quorum sensing as a communication technique which regulates the expression of virulence components. Fortunately, several phytochemicals have anti-QS characteristics that efficiently block QS pathways, prevent drug-resistant strains, and reduce biofilm development in chronic wounds. This review emphasizes the potential of phytocompounds as crucial agents for alleviating bacterial infections and promoting wound healing by reducing the inflammation in chronic wounds, exhibiting potential avenues for future therapeutic approaches to mitigate the healthcare burden provided by these challenging conditions.}, } @article {pmid38425549, year = {2024}, author = {Stoodley, P and Toelke, N and Schwermer, C and de Beer, D}, title = {Bioenergetics of simultaneous oxygen and nitrate respiration and nitric oxide production in a Pseudomonas aeruginosa agar colony biofilm.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100181}, doi = {10.1016/j.bioflm.2024.100181}, pmid = {38425549}, issn = {2590-2075}, abstract = {Pseudomonas aeruginosa is a biofilm forming pathogen commonly associated with infection of the cystic fibrosis (CF) lung, chronic wounds and indwelling medical devices. P. aeruginosa is a facultative aerobe that can use nitrate (NO3[-]) found in healthy and infected tissues and body fluids to generate energy through denitrification. Further, P. aeruginosa the expression of denitrification genes has been found in specimens from people with CF. The main aim of this study was to determine the relative energy contribution of oxygen (O2) respiration and denitrification in single Pseudomonas aeruginosa PAO1 biofilm colonies under different O2 concentrations to estimate the possible relative importance of these metabolic processes in the context of biofilm infections. We showed that the used strain PAO1 in biofilms denitrified with nitrous oxide (N2O), and not nitrogen (N2), as the end product in our incubations. From simultaneous O2 and N2O microprofiles measured with high spatial resolution by microsensors in agar colony biofilms under air, N2 and pure O2, the rates of aerobic respiration and denitrification were calculated and converted to ATP production rates. Denitrification occurred both in the oxic and anoxic zones, and became increasingly dominant with decreasing O2 concentrations. At O2 concentrations characteristic for tissues and wounds (20-60 μM), denitrification was responsible for 50% of the total energy conservation in the biofilm. In addition the formation of nitric oxide (NO), a precursor of N2O and an important regulator of many cellular processes, was strongly influenced by the local O2 concentrations. NO production was inhibited under pure O2, present under anoxia (∼1 μM) and remarkably high (up to 6 μM) under intermediate O2 levels, which can be found in infected tissues. Possible impacts of such NO levels on both the host and the biofilm bacteria are discussed.}, } @article {pmid38424684, year = {2024}, author = {Shenoy, V and Gunda, R and Noble, C and Haraguchi, A and Stevenson, S and Daniel, J}, title = {Fullertubes inhibit mycobacterial viability and prevent biofilm formation by disrupting the cell wall.}, journal = {Cell biochemistry and function}, volume = {42}, number = {2}, pages = {e3963}, doi = {10.1002/cbf.3963}, pmid = {38424684}, issn = {1099-0844}, support = {//Department of Biological Sciences, Purdue University Fort Wayne/ ; CHE-1856461//National Science Foundation for RUI/ ; //Purdue Fort Wayne Office of Sponsored Programs/ ; }, abstract = {Mycobacterium tuberculosis and nontuberculous mycobacteria such as Mycobacterium abscessus cause diseases that are becoming increasingly difficult to treat due to emerging antibiotic resistance. The development of new antimicrobial molecules is vital for combating these pathogens. Carbon nanomaterials (CNMs) are a class of carbon-containing nanoparticles with promising antimicrobial effects. Fullertubes (C90) are novel carbon allotropes with a structure unique among CNMs. The effects of fullertubes on any living cell have not been studied. In this study, we demonstrate that pristine fullertube dispersions show antimicrobial effects on Mycobacterium smegmatis and M. abscessus. Using scanning electron microscopy, light microscopy, and molecular probes, we investigated the effects of these CNMs on mycobacterial cell viability, cellular integrity, and biofilm formation. C90 fullertubes at 1 µM inhibited mycobacterial viability by 97%. Scanning electron microscopy revealed that the cell wall structure of M. smegmatis and M. abscessus was severely damaged within 24 h of exposure to fullertubes. Additionally, exposure to fullertubes nearly abrogated the acid-fast staining property of M. smegmatis. Using SYTO-9 and propidium iodide, we show that exposure to the novel fullertubes compromises the integrity of the mycobacterial cell. We also show that the permeability of the mycobacterial cell wall was increased after exposure to fullertubes from our assays utilizing the molecular probe dichlorofluorescein and ethidium bromide transport. C90 fullertubes at 0.37 µM and C60 fullerenes at 0.56 µM inhibited pellicle biofilm formation by 70% and 90%, respectively. This is the first report on the antimycobacterial activities of fullertubes and fullerenes.}, } @article {pmid38424381, year = {2024}, author = {Karahutová, L and Bujňáková, D}, title = {Antimicrobial and anti-biofilm efficacy of different inorganic and organic zinc forms against multidrug-resistant Escherichia, Klebsiella, Staphylococcus and Pseudomonas.}, journal = {Veterinary research communications}, volume = {}, number = {}, pages = {}, pmid = {38424381}, issn = {1573-7446}, abstract = {In our study antibacterial and anti-biofilm efficacy of 2 inorganics (Zn(II) sulphate monohydrate; Zn(II) sulphate heptahydrate) and 3 organic Zn(II) substances (Zn(II) chelate of protein hydrolysate: Zn-Bio; Zn(II) chelate of amino acid hydrate: Zn-AMK; Zn(II) chelate of glycine hydrate: Zn-Gly) were explored and compared against multidrug resistant Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Klebsiella oxytoca (K. oxytoca) and Pseudomonas aeruginosa (P. aeruginosa) using by the 96- wells microtiter plate-based resazurin and/or crystal violet assay. Our finding confirmed that Zn(II)-sulphates and Zn(II)-amino acid complexes exhibit dose and genus-based antibacterial and anti-biofilm potential. Organic compounds (Zn-AMK and Zn-Gly) were more effective against bacterial growth, except P. aeruginosa. Besides Zn-AMK, others organic and inorganic forms of Zn(II) caused predominantly statistically significant decrease of biofilm production in all of tested bacteria. Current data highlights that Zn(II) in various forms has a great potential to be developed as antibacterial and anti-biofilm agents.}, } @article {pmid38423606, year = {2024}, author = {Tao, H and Cao, X and Song, R and Zhou, Z and Cheng, F}, title = {Preparation of PDMS and PDMS-UiO-66 oxygen-rich membranes and modules for membrane-aerated biofilm reactors.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {89}, number = {4}, pages = {873-886}, doi = {10.2166/wst.2024.043}, pmid = {38423606}, issn = {0273-1223}, abstract = {A membrane-aerated biofilm reactor (MABR) combines membrane technology with biofilm processes and has unique advantages in the treatment of organic wastewater and volatile wastewater. The common membranes for MABR systems usually have relatively uneven pore structures and low bubble point pressure, resulting in unsatisfactory O2 utilization and wastewater treatment efficiency. In this work, polydimethylsiloxane (PDMS) and UiO-66 (a Zr-based metal organic framework) were coated on the surface of a commercial polypropylene (PP) hollow fiber membrane to prepare oxygen-rich MABR membranes and modules, which showed an attractive O2 utilization rate and wastewater treatment efficiency. The bubble points of the PDMS and PDMS-UiO-66 membranes were significantly higher than those of the PP membranes, and the PDMS-UiO-66 membranes had better oxygen enrichment capacity and biological affinity. The optimal PDMS-UiO-66 membrane modules had an O2 permeance of 31.65 GPU (1 GPU = 3.35 × 10[-10] mol m[-2] s[-1] Pa[-1]), with O2/N2 selectivity of 2.21. The membrane hanging effect and processing capacity for domestic sewage were greatly improved. This study may provide insights and guidelines to fabricate porous mixed matrix membranes and modules in the industry for MABR. The developed products are expected to be applied in the actual separation process.}, } @article {pmid38423404, year = {2024}, author = {Das, S and Malik, M and Dastidar, DG and Roy, R and Paul, P and Sarkar, S and Chakraborty, P and Maity, A and Dasgupta, M and Gupta, AD and Chatterjee, S and Sarker, RK and Maiti, D and Tribedi, P}, title = {Piperine, a phytochemical prevents the biofilm city of methicillin-resistant Staphylococcus aureus: A biochemical approach to understand the underlying mechanism.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106601}, doi = {10.1016/j.micpath.2024.106601}, pmid = {38423404}, issn = {1096-1208}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA), a drug-resistant human pathogen causes several nosocomial as well as community-acquired infections involving biofilm machinery. Hence, it has gained a wide interest within the scientific community to impede biofilm-induced MRSA-associated health complications. The current study focuses on the utilization of a natural bioactive compound called piperine to control the biofilm development of MRSA. Quantitative assessments like crystal violet, total protein recovery, and fluorescein-di-acetate (FDA) hydrolysis assays, demonstrated that piperine (8 and 16 μg/mL) could effectively compromise the biofilm formation of MRSA. Light and scanning electron microscopic image analysis confirmed the same. Further investigation revealed that piperine could reduce extracellular polysaccharide production by down-regulating the expression of icaA gene. Besides, piperine could reduce the cell-surface hydrophobicity of MRSA, a crucial factor of biofilm formation. Moreover, the introduction of piperine could interfere with microbial motility indicating the interaction of piperine with the quorum-sensing components. A molecular dynamics study showed a stable binding between piperine and AgrA protein (regulator of quorum sensing) suggesting the possible meddling of piperine in quorum-sensing of MRSA. Additionally, the exposure to piperine led to the accumulation of intracellular reactive oxygen species (ROS) and potentially heightened cell membrane permeability in inhibiting microbial biofilm formation. Besides, piperine could reduce the secretion of diverse virulence factors from MRSA. Further exploration revealed that piperine interacted with extracellular DNA (e-DNA), causing disintegration by weakening the biofilm architecture. Conclusively, this study suggests that piperine could be a potential antibiofilm molecule against MRSA-associated biofilm infections.}, } @article {pmid38422875, year = {2024}, author = {Ren, A and Yao, M and Fang, J and Dai, Z and Li, X and van der Meer, W and Medema, G and Rose, JB and Liu, G}, title = {Bacterial communities of planktonic bacteria and mature biofilm in service lines and premise plumbing of a Megacity: Composition, Diversity, and influencing factors.}, journal = {Environment international}, volume = {185}, number = {}, pages = {108538}, doi = {10.1016/j.envint.2024.108538}, pmid = {38422875}, issn = {1873-6750}, abstract = {Although simulated studies have provided valuable knowledge regarding the communities of planktonic bacteria and biofilms, the lack of systematic field studies have hampered the understanding of microbiology in real-world service lines and premise plumbing. In this study, the bacterial communities of water and biofilm were explored, with a special focus on the lifetime development of biofilm communities and their key influencing factors. The 16S rRNA gene sequencing results showed that both the planktonic bacteria and biofilm were dominated by Proteobacteria. Among the 15,084 observed amplicon sequence variants (ASVs), the 33 core ASVs covered 72.8 %, while the 12 shared core ASVs accounted for 62.2 % of the total sequences. Remarkably, it was found that the species richness and diversity of biofilm communities correlated with pipe age. The relative abundance of ASV2 (f_Sphingomonadaceae) was lower for pipe ages 40-50 years (7.9 %) than for pipe ages 10-20 years (59.3 %), while the relative abundance of ASV10 (f_Hyphomonadaceae) was higher for pipe ages 40-50 years (19.5 %) than its presence at pipe ages 20-30 years (1.9 %). The community of the premise plumbing biofilm had significantly higher species richness and diversity than that of the service line, while the steel-plastics composite pipe interior lined with polyethylene (S-PE) harbored significantly more diverse biofilm than the galvanized steel pipes (S-Zn). Interestingly, S-PE was enriched with ASV27 (g_Mycobacterium), while S-Zn pipes were enriched with ASV13 (g_Pseudomonas). Moreover, the network analysis showed that five rare ASVs, not core ASVs, were keystone members in biofilm communities, indicating the importance of rare members in the function and stability of biofilm communities. This manuscript provides novel insights into real-world service lines and premise plumbing microbiology, regarding lifetime dynamics (pipe age 10-50 years), and the influences of pipe types (premise plumbing vs. service line) and pipe materials (S-Zn vs. S-PE).}, } @article {pmid38422694, year = {2024}, author = {Lim, JH and Kang, JW}, title = {Assessing biofilm formation and resistance of vibrio parahaemolyticus on UV-aged microplastics in aquatic environments.}, journal = {Water research}, volume = {254}, number = {}, pages = {121379}, doi = {10.1016/j.watres.2024.121379}, pmid = {38422694}, issn = {1879-2448}, abstract = {UV degradation of marine microplastics (MPs) could increase their vector potential for pathogenic bacteria and threaten human health. However, little is known about how the degree of UV aging affects interactions between MPs and pathogens and how various types of MPs differ in their impact on seafood safety. This study investigated five types of UV-aged MPs and their impact on Vibrio parahaemolyticus, a seafood pathogen. MPs exposed to UV for 60 days showed similar physicochemical changes such as surface cracking and hydrophobicity reduction. Regardless of the type, longer UV exposure of MPs resulted in more biofilm formation on the surface under the same conditions. V. parahaemolyticus types that formed biofilms on the MP surface showed 1.4- to 5.0-fold upregulation of virulence-related genes compared to those that did not form biofilms, independently of UV exposure. However, longer UV exposure increased resistance of V. parahaemolyticus on MPs to chlorine, heat, and human gastrointestinal environment. This study implies that the more UV degradation occurs on MPs, the more microbial biofilm formation is induced, which can significantly increase virulence and environmental resistance of bacteria regardless of the type of MP.}, } @article {pmid38422239, year = {2024}, author = {Tuncer, G and Aktas, Z and Basaran, S and Cagatay, A and Eraksoy, H}, title = {Effect of N-acetyl cysteine, rifampicin, and ozone on biofilm formation in pan-resistant Klebsiella pneumoniae: an experimental study.}, journal = {Sao Paulo medical journal = Revista paulista de medicina}, volume = {142}, number = {4}, pages = {e2023113}, doi = {10.1590/1516-3180.2023.0113.R1.29112023}, pmid = {38422239}, issn = {1806-9460}, abstract = {BACKGROUND: To the best of our knowledge, this is the first study to evaluate the effectiveness of specific concentrations of antibiofilm agents, such as N-acetyl cysteine (NAC), rifampicin, and ozone, for the treatment of pan-resistant Klebsiella pneumoniae (PRKp).

OBJECTIVES: We evaluated the effectiveness of antibiofilm agents, such as NAC, rifampicin, and ozone, on biofilm formation in PRKp at 2, 6, 24, and 72 h.

DESIGN AND SETTING: This single-center experimental study was conducted on June 15, 2017, and July 15, 2018, at Istanbul Faculty of Medicine, Istanbul University, Turkey.

METHODS: Biofilm formation and the efficacy of these agents on the biofilm layer were demonstrated using colony counting and laser-screened confocal microscopy.

RESULTS: NAC at a final concentration of 2 μg/mL was administered to bacteria that formed biofilms (24 h), and no significant decrease was detected in the bacterial counts of all isolates (all P > 0.05). Rifampicin with a final concentration of 0.1 μg/mL was administered to bacteria that formed biofilm (24 h), and no significant decrease was detected in bacterial count (all P > 0.05). Notably, ozonated water of even 4.78 mg/L concentration for 72 h decreased the bacterial count by ≥ 2 log10.

CONCLUSION: Different approaches are needed for treating PRKp isolates. We demonstrate that PRKp isolates can be successfully treated with higher concentrations of ozone.}, } @article {pmid38421730, year = {2024}, author = {Horn, CM and Arumugam, P and Van Roy, Z and Heim, CE and Fallet, RW and Bertrand, BP and Shinde, D and Thomas, VC and Romanova, SG and Bronich, TK and Hartman, CW and Garvin, KL and Kielian, T}, title = {Granulocytic myeloid-derived suppressor cell activity during biofilm infection is regulated by a glycolysis-HIF1a axis.}, journal = {The Journal of clinical investigation}, volume = {}, number = {}, pages = {}, doi = {10.1172/JCI174051}, pmid = {38421730}, issn = {1558-8238}, abstract = {Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI). A primary contributor to infection chronicity is an expansion of granulocytic myeloid-derived suppressor cells (G-MDSCs) that are critical for orchestrating the anti-inflammatory biofilm milieu. Single-cell sequencing and bioinformatic metabolic algorithms were used to explore the link between G-MDSC metabolism and S. aureus PJI outcome. Glycolysis and the hypoxia response through hypoxia-inducible factor-1 alpha (HIF-1a) were significantly enriched in G-MDSCs. Interfering with both pathways in vivo, using a 2-deoxyglucose nanopreparation and granulocyte-targeted HIF-1a conditional knockout mice, respectively, attenuated G-MDSC-mediated immunosuppression and reduced bacterial burden in a mouse model of S. aureus PJI. In addition, scRNA-seq analysis of granulocytes from PJI patients also showed an enrichment in glycolysis and hypoxia response genes. These findings support the importance of a glycolysis/HIF-1a axis in promoting G-MDSC anti-inflammatory activity and biofilm persistence during PJI.}, } @article {pmid38421380, year = {2024}, author = {Santibáñez, N and Vega, M and Pérez, T and Enriquez, R and Escalona, CE and Oliver, C and Romero, A}, title = {In vitro effects of phytogenic feed additive on Piscirickettsia salmonis growth and biofilm formation.}, journal = {Journal of fish diseases}, volume = {}, number = {}, pages = {}, doi = {10.1111/jfd.13913}, pmid = {38421380}, issn = {1365-2761}, support = {FONDECYT1231761//Agencia Nacional de Investigación y Desarrollo ANID/ ; FONDAP1523A0004//Agencia Nacional de Investigación y Desarrollo ANID/ ; }, abstract = {Piscirickettsiosis is the main cause of mortality in salmonids of commercial importance in Chile, which is caused by Piscirickettsia salmonis, a Gram-negative, γ-proteobacteria that can produce biofilm as one of its virulence factors. The Chilean salmon industry uses large amounts of antibiotics to control piscirickettsiosis outbreaks, which has raised concern about its environmental impact and the potential to induce antibiotic resistance. Thus, the use of phytogenic feed additives (PFA) with antibacterial activity emerges as an interesting alternative to antimicrobials. Our study describes the antimicrobial action of an Andrographis paniculate-extracted PFA on P. salmonis planktonic growth and biofilm formation. We observed complete inhibition of planktonic and biofilm growth with 500 and 400 μg/mL of PFA for P. salmonis LF-89 and EM-90-like strains, respectively. Furthermore, 500 μg/mL of PFA was bactericidal for both evaluated bacterial strains. Sub-inhibitory doses of PFA increase the transcript levels of stress (groEL), biofilm (pslD), and efflux pump (acrB) genes for both P. salmonis strains in planktonic and sessile conditions. In conclusion, our results demonstrate the antibacterial effect of PFA against P. salmonis in vitro, highlighting the potential of PFA as an alternative to control Piscirickettsiosis.}, } @article {pmid38421161, year = {2024}, author = {Mlynek, KD and Toothman, RG and Martinez, EE and Qiu, J and Richardson, JB and Bozue, JA}, title = {Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis.}, journal = {Microbiology (Reading, England)}, volume = {170}, number = {2}, pages = {}, doi = {10.1099/mic.0.001437}, pmid = {38421161}, issn = {1465-2080}, abstract = {Two clinically important subspecies, Francisella tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B) are responsible for most tularaemia cases, but these isolates typically form a weak biofilm under in vitro conditions. Phase variation of the F. tularensis lipopolysaccharide (LPS) has been reported in these subspecies, but the role of variation is unclear as LPS is crucial for virulence. We previously demonstrated that a subpopulation of LPS variants can constitutively form a robust biofilm in vitro, but it is unclear whether virulence was affected. In this study, we show that biofilm-forming variants of both fully virulent F. tularensis subspecies were highly attenuated in the murine tularaemia model by multiple challenge routes. Genomic sequencing was performed on these strains, which revealed that all biofilm-forming variants contained a lesion within the wbtJ gene, a formyltransferase involved in O-antigen synthesis. A ΔwbtJ deletion mutant recapitulated the biofilm, O-antigen and virulence phenotypes observed in natural variants and could be rescued through complementation with a functional wbtJ gene. Since the spontaneously derived biofilm-forming isolates in this study were a subpopulation of natural variants, reversion events to the wbtJ gene were detected that eliminated the phenotypes associated with biofilm variants and restored virulence. These results demonstrate a role for WbtJ in biofilm formation, LPS variation and virulence of F. tularensis.}, } @article {pmid38420684, year = {2024}, author = {Wang, J and Zou, Z and Hu, M and Shan, X and Zhang, Y and Miao, Y and Zhang, X and Islam, N and Hu, Q}, title = {Riemerella anatipestifer UvrC is required for iron utilization, biofilm formation and virulence.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/03079457.2024.2317431}, pmid = {38420684}, issn = {1465-3338}, abstract = {Deletion of uvrC in R. anatipestfer Yb2 significantly reduced its biofilm formation.uvrC deletion led to reduced tolerance to H2O2- and HOCl-induced oxidative stress.The iron utilization of uvrC deleted mutant was significantly reduced.The uvrC deletion in R. anatipestifer Yb2 attenuated its virulence.}, } @article {pmid38419676, year = {2024}, author = {Tabussam, T and Shehnaz, H and Majeed, MI and Nawaz, H and Alghamdi, AA and Iqbal, MA and Shahid, M and Shahid, U and Umer, R and Rehman, MT and Farooq, U and Hassan, A and Imran, M}, title = {Surface-enhanced Raman spectroscopy for studying the interaction of organometallic compound bis(1,3-dihexylimidazole-2-yl) silver(i) hexafluorophosphate (v) with the biofilm of Escherichia coli.}, journal = {RSC advances}, volume = {14}, number = {10}, pages = {7112-7123}, pmid = {38419676}, issn = {2046-2069}, abstract = {Escherichia coli biofilms are a major cause of gastrointestinal tract diseases, such as esophageal, stomach and intestinal diseases. Nowadays, these are the most commonly occurring diseases caused by consuming contaminated food. In this study, we evaluated the efficacy of probiotics in controlling multidrug-resistant E. coli and reducing its ability to form biofilms. Our results substantiate the effective use of probiotics as antimicrobial alternatives and to eradicate biofilms formed by multidrug-resistant E. coli. In this research, surface enhanced Raman spectroscopy (SERS) was utilized to identify and evaluate Escherichia coli biofilms and their response to the varying concentrations of the organometallic compound bis(1,3-dihexylimidazole-2-yl) silver(i) hexafluorophosphate (v). Given the escalating challenge of antibiotic resistance in bacteria that form biofilms, understanding the impact of potential antibiotic agents is crucial for the healthcare sector. The combination of SERS with principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) enabled the detection and characterization of the biofilm, providing insights into the biochemical changes induced by the antibiotic candidate. The identified SERS spectral features served as indicators for elucidating the mode of action of the potential drug on the biofilm. Through PCA and PLS-DA, metabolic variations allowing the differentiation and classification of unexposed biofilms and biofilms exposed to different concentrations of the synthesized antibiotic were successfully identified, with 95% specificity, 96% sensitivity, and a 0.75 area under the curve (AUC). This research underscores the efficiency of surface enhanced Raman spectroscopy in differentiating the impact of potential antibiotic agents on E. coli biofilms.}, } @article {pmid38417885, year = {2024}, author = {Matsumoto, Y and Eshima, S and Kurakado, S and Sugita, T}, title = {A Silkworm Infection Model for Evaluating In Vivo Biofilm Formation by Pathogenic Fungi.}, journal = {Medical mycology journal}, volume = {65}, number = {1}, pages = {7-12}, doi = {10.3314/mmj.24.001}, pmid = {38417885}, issn = {1882-0476}, abstract = {Experimental animal models are necessary for research on infectious diseases. Generally, mammalian animals, such as mice, are used for infection experiments. However, there are ethical issues associated with conducting infection experiments in mammals. This has made it difficult to perform infection experiments with a large number of individuals. The invertebrate silkworm, Bombyx mori, is gaining attention as a model animal for infection experiments, and silkworm infection models with various pathogens have been established. This review provides information on the use of silkworm infection models for fungal infection research and evaluation of in vivo biofilm formation by pathogenic fungi using a novel silkworm experimental system. Various silkworm infection models with pathogenic fungi have been used for the development of antifungal drugs and the identification of fungal virulence-related genes. Furthermore, a catheter-material-inserted silkworm infection model was established to evaluate biofilm formation in vivo. Silkworm infection models have contributed to research on fungal infections.}, } @article {pmid38417723, year = {2024}, author = {Zhang, L and Bera, H and Guo, Y and Shi, C and Ulrik Lind, J and Radeke, C and Wang, J and Wang, H and Zhao, X and Cun, D and Yang, M}, title = {Co-spray dried inhalable composite powders of ciprofloxacin and alginate oligosaccharide as anti-biofilm therapy.}, journal = {International journal of pharmaceutics}, volume = {}, number = {}, pages = {123949}, doi = {10.1016/j.ijpharm.2024.123949}, pmid = {38417723}, issn = {1873-3476}, abstract = {The treatment of chronic respiratory infections caused by biofilm formation are extremely challenging owing to poor drug penetration into the complex biofilm structure and high drug resistance. Local delivery of an antibiotic together with a non-antibiotic adjuvant to the lungs could often enhance the therapeutic responses by targeting different bacterial growth pathways and minimizing drug resistance. In this study, we designed new inhalable dry powders containing ciprofloxacin (CIP) and OligoG (Oli, a low-molecular-weight alginate oligosaccharide impairing the mucoid biofilms by interacting with their cationic ions) to combat respiratory bacterial biofilm infections. The resulting powders were characterized with respect to their morphology, solid-state property, surface chemistry, moisture sorption behavior, and dissolution rate. The aerosol performance and storage stability of the dry powders were also evaluated. The results showed that inhalable dry powders composed of CIP and Oli could be readily accomplished via the wet milling and spray drying process. Upon the storage under 20 ± 2 °C/20 ± 2 % relative humidity (RH) for one month, there was no significant change in the in vitro aerosol performances of the dry powders. In contrast, the dry powders became non-inhalable following the storage at 20 ± 2 °C/53 ± 2 % RH for one month due to the hygroscopic nature of Oli, which could be largely prevented by incorporation of leucine. Collectively, this study suggests that the newly developed co-spray-dried powders composed of CIP and Oli might represent a promising and alternative treatment strategy against respiratory bacterial biofilm infections.}, } @article {pmid38417645, year = {2024}, author = {Jeong, GJ and Khan, F and Tabassum, N and Cho, KJ and Kim, YM}, title = {Bacterial extracellular vesicles: modulation of biofilm formation and virulence.}, journal = {Acta biomaterialia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.actbio.2024.02.029}, pmid = {38417645}, issn = {1878-7568}, abstract = {Microbial pathogens cause persistent infections by forming biofilms and producing numerous virulence factors. Bacterial extracellular vesicles (BEVs) are nanostructures produced by various bacterial species vital for molecular transport. BEVs include various components, including lipids (glycolipids, LPS, and phospholipids), nucleic acids (genomic DNA, plasmids, and short RNA), proteins (membrane proteins, enzymes, and toxins), and quorum-sensing signaling molecules. BEVs play a major role in forming extracellular polymeric substances (EPS) in biofilms by transporting EPS components such as extracellular polysaccharides, proteins, and extracellular DNA. BEVs have been observed to carry various secretory virulence factors. Thus, BEVs play critical roles in cell-to-cell communication, biofilm formation, virulence, disease progression, and resistance to antimicrobial treatment. In contrast, BEVs have been shown to impede early-stage biofilm formation, disseminate mature biofilms, and reduce virulence. This review summarizes the current status in the literature regarding the composition and role of BEVs in microbial infections. Furthermore, the dual functions of BEVs in eliciting and suppressing biofilm formation and virulence in various microbial pathogens are thoroughly discussed. This review is expected to improve our understanding of the use of BEVs in determining the mechanism of biofilm development in pathogenic bacteria and in developing drugs to inhibit biofilm formation by microbial pathogens. STATEMENT OF SIGNIFICANCE: Bacterial extracellular vesicles (BEVs) are nanostructures formed by membrane blebbing and explosive cell lysis. It is essential for transporting lipids, nucleic acids, proteins, and quorum-sensing signaling molecules. BEVs play an important role in the formation of the biofilm's extracellular polymeric substances (EPS) by transporting its components, such as extracellular polysaccharides, proteins, and extracellular DNA. Furthermore, BEVs shield genetic material from nucleases and thermodegradation by packaging it during horizontal gene transfer, contributing to the transmission of bacterial adaptation determinants like antibiotic resistance. Thus, BEVs play a critical role in cell-to-cell communication, biofilm formation, virulence enhancement, disease progression, and drug resistance. In contrast, BEVs have been shown to prevent early-stage biofilm, disperse mature biofilm, and reduce virulence characteristics.}, } @article {pmid38415850, year = {2024}, author = {Kumar, VB and Lahav, M and Gazit, E}, title = {Preventing biofilm formation and eradicating pathogenic bacteria by Zn doped histidine derived carbon quantum dots.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb02488a}, pmid = {38415850}, issn = {2050-7518}, abstract = {Bacterial infections are of major medical concern due to antibiotic resistance. Carbon quantum dots (CDs) have emerged as potentially excellent biomaterials for multifunctional applications due to their low toxicity, outstanding water solubility, high fluorescence, and high biocompatibility. All of these properties allow CDs to be exceptional biomaterials for inhibiting the growth of bacteria and stopping biofilm formation due to their strong binding affinity, cell wall penetration, and solubilizing biofilm in water. Here, we describe a strategy for one-pot synthesis of histidine-derived zinc-doped N-doped CDs (Zn-NCDs) by a hydrothermal method for inhibiting the growth of both Gram-positive and Gram-negative bacteria without harming mammalian cells. The NCDs and Zn-NCDs showed uniform sizes (∼6 nm), crystallinity, good photostability, high quantum yield (76%), and long decay time (∼5 ns). We also studied their utilization for live cell bio-imaging and the antimicrobial properties towards the Gram-positive Staphylococcus aureus and the Gram-negative Pseudomonas aeruginosa. Importantly, the Zn-NCDs could penetrate the biofilm and bacterial cell wall to effectively inhibit the growth of bacteria and subsequently inhibit biofilm formation. Thus, the structure, chemical composition, and low toxicity properties of the newly-developed Zn-NCDs exemplify a promising novel method for the preparation of nano-level antibacterial drugs.}, } @article {pmid38414729, year = {2024}, author = {Chimi, LY and Noubom, M and Bisso, BN and Singor Njateng, GS and Dzoyem, JP}, title = {Biofilm Formation, Pyocyanin Production, and Antibiotic Resistance Profile of Pseudomonas aeruginosa Isolates from Wounds.}, journal = {International journal of microbiology}, volume = {2024}, number = {}, pages = {1207536}, pmid = {38414729}, issn = {1687-918X}, abstract = {Pseudomonas aeruginosa is one of the most frequently resistant and dangerous bacteria isolated from infected wounds of patients. This study aimed to determine the prevalence of P. aeruginosa from infected wounds of patients in the Dschang District Hospital to evaluate their antibiotic susceptibility profiles and their ability to swarm and swim and correlate pyocyanin production with biofilm formation. Wound swab samples were collected and the identification of P. aeruginosa was performed using microbiological and biochemical tests. Their antimicrobial susceptibility was determined by the broth microdilution method. Swarming and swimming were determined by measuring the diameters of motility in semisolid/low-viscosity media. Furthermore, pyocyanin production and biofilm formation were evaluated spectrophotometrically using a microtiter plate. The prevalence of P. aeruginosa from infected wounds in our study population was 26%. All P. aeruginosa isolates were resistant to streptomycin and paromomycin, and the frequency of multidrug resistance (MDR) was 65.8%. All P. aeruginosa isolates showed the ability to produce biofilm and pyocyanin. Out of the 37 isolates screened, 19 including the reference strains (51.4%) were strong biofilm producers. A significant positive correlation was observed among biofilm formation, pyocyanin production, and the antibiotic resistance profile of the isolates. Findings from this study suggest that infected wounds could act as a reservoir for MDR and virulent P. aeruginosa. The presence of strong biofilm producers of P. aeruginosa in infected wounds is a serious public health concern. Therefore, surveillance programs to monitor and control MDR P. aeruginosa in these patients are required to prevent their dissemination in hospital settings.}, } @article {pmid38414711, year = {2023}, author = {Mougin, J and Midelet, G and Leterme, S and Best, G and Ells, T and Joyce, A and Whiley, H and Brauge, T}, title = {Benzalkonium chloride disinfectant residues stimulate biofilm formation and increase survival of Vibrio bacterial pathogens.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1309032}, pmid = {38414711}, issn = {1664-302X}, abstract = {Vibrio spp. are opportunistic human and animal pathogens found ubiquitously in marine environments. Globally, there is a predicted rise in the prevalence of Vibrio spp. due to increasing ocean temperatures, which carries significant implications for public health and the seafood industry. Consequently, there is an urgent need for enhanced strategies to control Vibrio spp. and prevent contamination, particularly in aquaculture and seafood processing facilities. Presently, these industries employ various disinfectants, including benzalkonium chloride (BAC), as part of their management strategies. While higher concentrations of BAC may be effective against these pathogens, inadequate rinsing post-disinfection could result in residual concentrations of BAC in the surrounding environment. This study aimed to investigate the adaptation and survival of Vibrio spp. exposed to varying concentrations of BAC residues. Results revealed that Vibrio bacteria, when exposed, exhibited a phenotypic adaptation characterized by an increase in biofilm biomass. Importantly, this effect was found to be strain-specific rather than species-specific. Exposure to BAC residues induced physiological changes in Vibrio biofilms, leading to an increase in the number of injured and alive cells within the biofilm. The exact nature of the "injured" bacteria remains unclear, but it is postulated that BAC might heighten the risk of viable but non-culturable (VBNC) bacteria development. These VBNC bacteria pose a significant threat, especially since they cannot be detected using the standard culture-based methods commonly employed for microbiological risk assessment in aquaculture and seafood industries. The undetected presence of VBNC bacteria could result in recurrent contamination events and subsequent disease outbreaks. This study provides evidence regarding the role of c-di-GMP signaling pathways in Vibrio adaptation mechanisms and suggests that c-di-GMP mediated repression is a potential avenue for further research. The findings underscore that the misuse and overuse of BAC may increase the risk of biofilm development and bacterial survival within the seafood processing chain.}, } @article {pmid38412631, year = {2024}, author = {Zhang, Y and Sang, P and Wang, K and Gao, J and Liu, Q and Wang, J and Qian, F and Shu, Y and Hong, P}, title = {Enhanced chromium and nitrogen removal by constructing a biofilm reaction system based on denitrifying bacteria preferential colonization theory.}, journal = {Ecotoxicology and environmental safety}, volume = {273}, number = {}, pages = {116156}, doi = {10.1016/j.ecoenv.2024.116156}, pmid = {38412631}, issn = {1090-2414}, abstract = {Understanding the developmental characteristics of microbial communities in biofilms is crucial for designing targeted functional microbial enhancements for the remediation of complex contamination scenarios. The strong prioritization effect of microorganisms confers the ability to colonize strains that arrive first dominantly. In this study, the auto-aggregating denitrifying bacterial Pseudomonas stutzeri strain YC-34, which has both nitrogen and chromium removal characteristics, was used as a biological material to form a stable biofilm system based on the principle of dominant colonization and biofortification. The effect of the biofilm system on nitrogen and chromium removal was characterized by measuring the changes in the quality of influent and effluent water. The pattern of biofilm changes was analyzed by measuring biofilm content and thickness and characterizing extracellular polymer substances (EPS). Further analysis of the biofilm microbiota characteristics and potential functions revealed the mechanism of strain YC-34 biofortified biofilm. The results revealed that the biofilm system formed could achieve 90.56% nitrate-nitrogen removal with an average initial nitrate-nitrogen concentration of 51.9 mg/L and 40% chromium removal with an average initial hexavalent chromium Cr(VI) concentration of 7.12 mg/L. The biofilm properties of the system were comparatively analyzed during the biofilm formation period, the fluctuation period of Cr(VI)-stressed water quality, and the stabilization period of Cr(VI)-stressed water quality. The biofilm system may be able to increase the structure of hydrogen bonds, the type of protein secondary structure, and the abundance of amino acid-like components in the EPS, which may confer biofilm tolerance to Cr(VI) stress and allow the system to maintain a stable biofilm structure. Furthermore, microbial characterization indicated an increase in microbial diversity in the face of chromium stress, with an increase in the abundance of nitrogen removal-associated functional microbiota and an increasing trend in the abundance of nitrogen transfer pathways. These results demonstrate that the biofilm system is stable in nitrogen and chromium removal. This bioaugmentation method may provide a new way for the remediation of heavy metal-polluted water bodies and also provides theoretical and application parameters for the popularization and application of biofilm systems.}, } @article {pmid38412335, year = {2024}, author = {Fang, ZY and Zhang, ZY and Zheng, YD and Lei, D and Zhuang, J and Li, N and He, QY and Sun, X}, title = {Repurposing cinacalcet suppresses multidrug-resistant Staphylococcus aureus by disruption of cell membrane and inhibits biofilm by targeting IcaR.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {}, number = {}, pages = {}, doi = {10.1093/jac/dkae051}, pmid = {38412335}, issn = {1460-2091}, support = {21977037//National Natural Science Foundation of China/ ; 2022A1515010674//Guangdong National Science Foundation/ ; 2017YFA0505100//National Key R & D Program of China/ ; 25076//International Atomic Energy Agency Coordinated Research Project/ ; }, abstract = {BACKGROUND: MDR Staphylococcus aureus infections, along with the severity of biofilm-associated infections, continue to threaten human health to a great extent. It necessitates the urgent development of novel antimicrobial and antibiofilm agents.

OBJECTIVES: To reveal the mechanism and target of cinacalcet as an antibacterial and antimicrobial agent for S. aureus.

METHODS: Screening of non-antibiotic drugs for antibacterial and antibiofilm properties was conducted using a small-molecule drug library. In vivo efficacy was assessed through animal models, and the antibacterial mechanism was studied using quantitative proteomics, biochemical assays, LiP-SMap, BLI detection and gene knockout techniques.

RESULTS: Cinacalcet, an FDA-approved drug, demonstrated antibacterial and antibiofilm activity against S. aureus, with less observed development of bacterial resistance. Importantly, cinacalcet significantly improved survival in a pneumonia model and bacterial clearance in a biofilm infection model. Moreover, the antibacterial mechanism of cinacalcet mainly involves the destruction of membrane-targeted structures, alteration of energy metabolism, and production of reactive oxygen species (ROS). Cinacalcet was found to target IcaR, inhibiting biofilm formation through the negative regulation of IcaADBC.

CONCLUSIONS: The findings suggest that cinacalcet has potential for repurposing as a therapeutic agent for MDR S. aureus infections and associated biofilms, warranting further investigation.}, } @article {pmid38411953, year = {2024}, author = {David, A and Tahrioui, A and Duchesne, R and Tareau, A-S and Maillot, O and Barreau, M and Feuilloley, MGJ and Lesouhaitier, O and Cornelis, P and Bouffartigues, E and Chevalier, S}, title = {Membrane fluidity homeostasis is required for tobramycin-enhanced biofilm in Pseudomonas aeruginosa.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0230323}, doi = {10.1128/spectrum.02303-23}, pmid = {38411953}, issn = {2165-0497}, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen, which causes chronic infections, especially in cystic fibrosis (CF) patients where it colonizes the lungs via the build-up of biofilms. Tobramycin, an aminoglycoside, is often used to treat P. aeruginosa infections in CF patients. Tobramycin at sub-minimal inhibitory concentrations enhances both biofilm biomass and thickness in vitro; however, the mechanism(s) involved are still unknown. Herein, we show that tobramycin increases the expression and activity of SigX, an extracytoplasmic sigma factor known to be involved in the biosynthesis of membrane lipids and membrane fluidity homeostasis. The biofilm enhancement by tobramycin is not observed in a sigX mutant, and the sigX mutant displays increased membrane stiffness. Remarkably, the addition of polysorbate 80 increases membrane fluidity of sigX-mutant cells in biofilm, restoring the tobramycin-enhanced biofilm formation. Our results suggest the involvement of membrane fluidity homeostasis in biofilm development upon tobramycin exposure.IMPORTANCEPrevious studies have shown that sub-lethal concentrations of tobramycin led to an increase biofilm formation in the case of infections with the opportunistic pathogen Pseudomonas aeruginosa. We show that the mechanism involved in this phenotype relies on the cell envelope stress response, triggered by the extracytoplasmic sigma factor SigX. This phenotype was abolished in a sigX-mutant strain. Remarkably, we show that increasing the membrane fluidity of the mutant strain is sufficient to restore the effect of tobramycin. Altogether, our data suggest the involvement of membrane fluidity homeostasis in biofilm development upon tobramycin exposure.}, } @article {pmid38409443, year = {2024}, author = {Loewe, MF and Doll-Nikutta, K and Stiesch, M and Schwestka-Polly, R}, title = {Biofilm volume and acidification within initial biofilms formed in situ on buccally and palatally exposed bracket material.}, journal = {Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie}, volume = {}, number = {}, pages = {}, pmid = {38409443}, issn = {1615-6714}, abstract = {PURPOSE: Acidification by bacterial biofilms at the bracket/tooth interface is one of the most common problems in fixed orthodontic treatments, which can lead to white spot lesions (WSL) and caries. As lingual brackets were shown to exhibit reduced WSL formation clinically, the aim of this in situ study was to compare initial intraoral biofilm formation and acidification on bracket-like specimens placed buccally and palatally in the upper jaw as a possible cause for this observation.

METHODS: Intraoral biofilm was collected from splints equipped with buccally and palatally exposed test specimens, which were worn by 12 volunteers for a total of 48 h. The test specimens consisted of standard bracket material cylinders on top of a hydroxyapatite disc to represent the bracket/tooth interface. They were analyzed for three-dimensional biofilm volume and live/dead distribution by fluorescence staining and confocal laser scanning microscopy as well as for acidification by fluorescence-based pH ratiometry.

RESULTS: Similar general biofilm morphology with regard to volume and viability could be detected for buccally and palatally exposed specimens. For pH values, biofilms from both positions showed increased acidification at the bottom layer. Interestingly, the pH value at the top layers of the biofilms was slightly lower on palatally than on buccally exposed specimens, which may likely be due to anatomic conditions.

CONCLUSION: Based on the results of this study, initial intraoral biofilm formation and acidification is almost similar on the bracket material/biomimetic tooth interface when placed buccally or palatally in the upper jaw. As lingual brackets were shown to exhibit reduced WSL formation clinically, future studies should investigate further factors like bracket geometry.}, } @article {pmid38408138, year = {2024}, author = {Ding, J and Wang, X and Liu, W and Ding, C and Wu, J and He, R and Zhang, X}, title = {Biofilm Microenvironment Activated Antibiotic Adjuvant for Implant-Associated Infections by Systematic Iron Metabolism Interference.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2400862}, doi = {10.1002/advs.202400862}, pmid = {38408138}, issn = {2198-3844}, support = {20YF1436100//Shanghai Sailing Program/ ; 22YF1433300//Shanghai Sailing Program/ ; 82102539//Innovative Research Group Project of the National Natural Science Foundation of China/ ; }, abstract = {Hematoma, a risk factor of implant-associated infections (IAIs), creates a Fe-rich environment following implantation, which proliferates the growth of pathogenic bacteria. Fe metabolism is a major vulnerability for pathogens and is crucial for several fundamental physiological processes. Herein, a deferiprone (DFP)-loaded layered double hydroxide (LDH)-based nanomedicine (DFP@Ga-LDH) that targets the Fe-rich environments of IAIs is reported. In response to acidic changes at the infection site, DFP@Ga-LDH systematically interferes with bacterial Fe metabolism via the substitution of Ga[3+] and Fe scavenging by DFP. DFP@Ga-LDH effectively reverses the Fe/Ga ratio in Pseudomonas aeruginosa, causing comprehensive interference in various Fe-associated targets, including transcription and substance metabolism. In addition to its favorable antibacterial properties, DFP@Ga-LDH functions as a nano-adjuvant capable of delaying the emergence of antibiotic resistance. Accordingly, DFP@Ga-LDH is loaded with a siderophore antibiotic (cefiderocol, Cefi) to achieve the antibacterial nanodrug DFP@Ga-LDH-Cefi. Antimicrobial and biosafety efficacies of DFP@Ga-LDH-Cefi are validated using ex vivo human skin and mouse IAI models. The pivotal role of the hematoma-created Fe-rich environment of IAIs is highlighted, and a nanoplatform that efficiently interferes with bacterial Fe metabolism is developed. The findings of the study provide promising guidance for future research on the exploration of nano-adjuvants as antibacterial agents.}, } @article {pmid38407199, year = {2024}, author = {Pesset, CM and Fonseca, COD and Antunes, M and Santos, ALLD and Teixeira, IM and Ferreira, EO and Penna, B}, title = {Biofilm formation by Staphylococcus pseudintermedius on titanium implants.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/08927014.2024.2320721}, pmid = {38407199}, issn = {1029-2454}, abstract = {Osteomyelitis often involves Staphylococcus spp. as the isolated genus in domestic animal cases. Implant-related infections, frequently associated with biofilm-forming microorganisms like staphylococci species, necessitate careful material selection. This study assessed biofilm formation by Staphylococcus pseudintermedius on titanium nuts used in veterinary orthopaedic surgery. Biofilm quantification employed safranin staining and spectrophotometric measurement, while bacterial counts were determined in colony-forming units (CFU). Scanning Electron Microscopy (SEM) evaluated the biofilm morphology on the surface of titanium nuts. All samples had CFU counts. Absorbance values that evidence biofilm formation were observed in seven of the eight samples tested. SEM images revealed robust bacterial colonization, and significant extracellular polymeric substance production, and the negative control displayed surface irregularities on the nut. Whole genome sequencing revealed accessory Gene Regulator (agr) type III in six samples, agr IV and agr II in two each. Genes encoding hlb, luk-S, luk-F, siet, se_int, and the icaADCB operon were identified in all sequenced samples. Other exfoliative toxins were absent. Biofilm formation by S. pseudintermedius was detected in all samples, indicating the susceptibility of orthopaedic titanium alloys to adhesion and biofilm formation by veterinary species. The biofilm formation capacity raises concerns about potential post-surgical complications and associated costs.}, } @article {pmid38406363, year = {2024}, author = {Kanaan, MHG}, title = {Effect of biofilm formation in a hostile oxidative stress environment on the survival of Campylobacter jejuni recovered from poultry in Iraqi markets.}, journal = {Veterinary world}, volume = {17}, number = {1}, pages = {136-142}, pmid = {38406363}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Campylobacter jejuni is a major contributor to bacterial enteritis, a common health problem. The resistance of this microaerophilic bacterium to oxidative stress allows it to thrive under aerobic conditions. This study aimed to investigate whether the capacity of C. jejuni to form biofilms in the presence of oxidative stress contributes to the pathogen's ability to thrive in agricultural settings as well as in chicken slaughter lines.

MATERIALS AND METHODS: Twenty identified strains originating from chicken samples (eight from caeca contents and 12 from frozen chicken carcasses) were previously isolated and identified according to standard bacteriological protocols, followed by confirmation at the species level using multiplex polymerase chain reaction assay. Crystal violet staining was used to evaluate biofilm formation by these bacteria. Two exposure periods to gaseous ozone (1 and 2 min) were used to assess resistance to oxidative damage.

RESULTS: Most of the strong biofilm-forming Campylobacter strains came from imported frozen chicken meat (25%), whereas only 10% came from caeca content. After exposure to gaseous ozone at 600 mg/h for 2 min, strong biofilm-producing strains exhibited a higher survival rate with a limited reduction of up to 3 logs, whereas negative biofilm-producing strains exhibited a limited survival rate with a reduction of 6 logs.

CONCLUSION: Based on our findings, we hypothesized that the presence of C. jejuni strains capable of forming biofilms in poultry farms and/or chicken production facilities triggers a public health alarm as this bacterium seems to be able to adapt more easily to live and thrive in hostile environmental conditions.}, } @article {pmid38406288, year = {2024}, author = {Santos, LM and Rodrigues, DM and Alves, BVB and Kalil, MA and Azevedo, V and Barh, D and Meyer, R and Duran, N and Tasic, L and Portela, RW}, title = {Activity of biogenic silver nanoparticles in planktonic and biofilm-associated Corynebacterium pseudotuberculosis.}, journal = {PeerJ}, volume = {12}, number = {}, pages = {e16751}, pmid = {38406288}, issn = {2167-8359}, abstract = {Corynebacterium pseudotuberculosis is a gram-positive bacterium and is the etiologic agent of caseous lymphadenitis (CL) in small ruminants. This disease is characterized by the development of encapsulated granulomas in visceral and superficial lymph nodes, and its clinical treatment is refractory to antibiotic therapy. An important virulence factor of the Corynebacterium genus is the ability to produce biofilm; however, little is known about the characteristics of the biofilm produced by C. pseudotuberculosis and its resistance to antimicrobials. Silver nanoparticles (AgNPs) are considered as promising antimicrobial agents, and are known to have several advantages, such as a broad-spectrum activity, low resistance induction potential, and antibiofilm activity. Therefore, we evaluate herein the activity of AgNPs in C. pseudotuberculosis, through the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antibiofilm activity, and visualization of AgNP-treated and AgNP-untreated biofilm through scanning electron microscopy. The AgNPs were able to completely inhibit bacterial growth and inactivate C. pseudotuberculosis at concentrations ranging from 0.08 to 0.312 mg/mL. The AgNPs reduced the formation of biofilm in reference strains and clinical isolates of C. pseudotuberculosis, with interference values greater than 80% at a concentration of 4 mg/mL, controlling the change between the planktonic and biofilm-associated forms, and preventing fixation and colonization. Scanning electron microscopy images showed a significant disruptive activity of AgNP on the consolidated biofilms. The results of this study demonstrate the potential of AgNPs as an effective therapeutic agent against CL.}, } @article {pmid38405794, year = {2024}, author = {Malik, A and Oludiran, A and Poudel, A and Alvarez, OB and Woodward, C and Purcell, EB}, title = {RelQ-mediated alarmone signaling regulates growth, sporulation, and stress-induced biofilm formation in Clostridioides difficile.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {38405794}, abstract = {The bacterial stringent response (SR) is a conserved transcriptional reprogramming pathway mediated by the nucleotide signaling alarmones, (pp)pGpp. The SR has been implicated in antibiotic survival in Clostridioides difficile , a biofilm- and spore-forming pathogen that causes resilient, highly recurrent C. difficile infections. The role of the SR in other processes and the effectors by which it regulates C. difficile physiology are unknown. C. difficile RelQ is a clostridial alarmone synthetase. Deletion of relQ dysregulates C. difficile growth in unstressed conditions, affects susceptibility to antibiotic and oxidative stressors, and drastically reduces biofilm formation. While wild-type C. difficile displays increased biofilm formation in the presence of sub-lethal stress, the Δ relQ strain cannot upregulate biofilm production in response to stress. Deletion of relQ slows spore accumulation in planktonic cultures but accelerates it in biofilms. This work establishes biofilm formation and sporulation as alarmone-mediated processes in C. difficile and reveals the importance of RelQ in stress-induced biofilm regulation.}, } @article {pmid38405588, year = {2024}, author = {Yasmeen, T and Arif, MS and Tariq, M and Akhtar, S and Syrish, A and Haidar, W and Rizwan, M and Hussain, MI and Ahmad, A and Ali, S}, title = {Biofilm producing plant growth promoting bacteria in combination with glycine betaine uplift drought stress tolerance of maize plant.}, journal = {Frontiers in plant science}, volume = {15}, number = {}, pages = {1327552}, pmid = {38405588}, issn = {1664-462X}, abstract = {INTRODUCTION: The escalating threat of drought poses a significant challenge to sustainable food production and human health, as water scarcity adversely impacts various aspects of plant physiology. Maize, a cornerstone in staple cereal crops, faces the formidable challenge of drought stress that triggers a series of transformative responses in the plant.

METHODS: The present study was carried out in two sets of experiments. In first experiment, drought stress was applied after maintaining growth for 45 days and then irrigation was skipped, and plant samples were collected at 1[st], 3[rd] and 6[th] day of drought interval for evaluation of changes in plant growth, water relation (relative water content) and antioxidants activity by inoculating indigenously isolated drought tolerant biofilm producing rhizobacterial isolates (Bacillus subtilis SRJ4, Curtobacterium citreum MJ1). In the second experiment, glycine betaine was applied as osmoregulator in addition to drought tolerant PGPR to perceive modulation in photosynthetic pigments (Chlorophyll a and b) and plant growth under varying moisture stress levels (100, 75 and 50% FC).

RESULTS AND DISCUSSION: Results of the study revealed upsurge in root and shoot length, fresh and dry biomass of root and shoot besides increasing chlorophyll contents in water stressed inoculated plants compared to uninoculated plants. Glycine betaine application resulted in an additional boost to plant growth and photosynthetic pigments, when applied in combination with bacterial inoculants. However, both bacterial inoculants behaved differently under drought stress as evident from their biochemical and physiological attributes. Isolate SRJ4 proved to be superior for its potential to express antioxidant activity, leaf water potential and relative water contents and drought responsive gene expression while isolate MJ1 showed exclusive increase in root dry biomass and plant P contents. Though it is quite difficult to isolate the bacterial isolates having both plant growth promoting traits and drought tolerance together yet, such biological resources could be an exceptional option to be applied for improving crop productivity and sustainable agriculture under abiotic stresses. By exploring the combined application of PGPR and glycine betaine, the study seeks to provide insights into potential strategies for developing sustainable agricultural practices aimed at improving crop resilience under challenging environmental conditions.}, } @article {pmid38404331, year = {2024}, author = {Camba, C and Walter-Lakes, B and Digal, P and Taheri-Araghi, S and Bezryadina, A}, title = {Biofilm formation and manipulation with optical tweezers.}, journal = {Biomedical optics express}, volume = {15}, number = {2}, pages = {1181-1191}, pmid = {38404331}, issn = {2156-7085}, abstract = {Some bacterial species form biofilms in suboptimal growth and environmental conditions. Biofilm structures allow the cells not only to optimize growth with nutrient availability but also to defend each other against external stress, such as antibiotics. Medical and bioengineering implications of biofilms have led to an increased interest in the regulation of bacterial biofilm formation. Prior research has primarily focused on mechanical and chemical approaches for stimulating and controlling biofilm formation, yet optical techniques are still largely unexplored. In this paper, we investigate the biofilm formation of Bacillus subtilis in a minimum biofilm-promoting medium (MSgg media) and explore the potential of optical trapping in regulating bacterial aggregation and biofilm development. Specifically, we determine the most advantageous stage of bacterial biofilm formation for optical manipulation and investigate the impact of optical trapping at different wavelengths on the aggregation of bacterial cells and the formation of biofilm. The investigation of optically regulated biofilm formation with optical tweezers presents innovative methodologies for the stimulation and suppression of biofilm growth through the application of lasers.}, } @article {pmid38404175, year = {2024}, author = {Macedo, FPG and Soares, AJ and Marceliano-Alves, MFV and Martinez, E and Lopes, R and Bastos, LF and Nascimento, WM and Limoeiro, AG and Dos Frozoni, M}, title = {The effect of root canal preparation tapers on planktonic bacteria and biofilm reduction in the apical third: A correlative microtomography and microbiological laboratory study.}, journal = {International endodontic journal}, volume = {}, number = {}, pages = {}, doi = {10.1111/iej.14052}, pmid = {38404175}, issn = {1365-2591}, abstract = {AIM: To evaluate the influence of different preparation tapers on the reduction in planktonic bacteria and biofilms of Enterococcus faecalis and Candida albicans in the apical third (4 mm) of the mesial roots of mandibular molars, correlating decontamination with canal shape.

METHODOLOGY: After microtomography analysis for morphological standardization of the canals, 48 mandibular molar roots, each containing two canals (96 canals), were contaminated with E. faecalis and C. albicans and divided into four groups (n = 11) for canal instrumentation using ProDesign Logic 2 files with different tapers G (.03): # 25.03; G (.04): # 25.04; G (.05): # 25.05; and G (.06): # 25.06 and irrigation with 2.5% sodium hypochlorite. Four roots were examined under a scanning electron microscope (SEM) to qualitatively assess biofilm formation. Eight roots were used as the negative control group (samples were not contaminated). Bacteriological samples were taken exclusively from the apical third of the roots before and after chemical-mechanical preparation and bacterial counts were determined (CFU/mL). The final micro-CT scan was used to quantify the volume variation and unprepared canal area in the apical third. Statistical analysis was performed using the Kruskal-Wallis, Student-Newman-Keuls and Wilcoxon tests for analysis of microbiological data. anova and the Tukey or Games-Howell test were used for analysis of micro-CT data and Spearman's test for correlations (α = 5%).

RESULTS: All groups showed a significant reduction in bacteria (p < .05), with no statistically significant difference between groups. There was no significant difference in per cent volume increase between groups. The unprepared area (Δ%) was affected by the file used (p = .026) and was significantly lower for G (.06) compared to G (.03). There was no statistically significant correlation among bacterial reduction, volume and unprepared area (p > .05).

CONCLUSION: The different preparation tapers influenced root canal shaping in the apical third but did not improve decontamination in this region.}, } @article {pmid38403876, year = {2024}, author = {Blanco-Cabra, N and Alcàcer-Almansa, J and Admella, J and Arévalo-Jaimes, BV and Torrents, E}, title = {Nanomedicine against biofilm infections: A roadmap of challenges and limitations.}, journal = {Wiley interdisciplinary reviews. Nanomedicine and nanobiotechnology}, volume = {16}, number = {1}, pages = {e1944}, doi = {10.1002/wnan.1944}, pmid = {38403876}, issn = {1939-0041}, support = {2021SGR-01545//Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya/ ; FQxxx01//'la Caixa' Foundation/ ; LCF/BQ/DI20/11780040//'la Caixa' Foundation/ ; PLEC2022-009356//Ministerio de Ciencia e Innovación/ ; PDC2022-133577-I00//Ministerio de Ciencia e Innovación/ ; PID2021-125801OB-100//Ministerio de Ciencia e Innovación/ ; PRE2021-098703//Ministerio de Ciencia e Innovación/ ; //European Regional Development Fund (FEDER)/ ; //Catalan Cystic Fibrosis Association/ ; //European Union-Next Generation EU/ ; 2021FI_B00118//Generalitat de Catalunya/ ; }, abstract = {Microbial biofilms are complex three-dimensional structures where sessile microbes are embedded in a polymeric extracellular matrix. Their resistance toward the host immune system as well as to a diverse range of antimicrobial treatments poses a serious health and development threat, being in the top 10 global public health threats declared by the World Health Organization. In an effort to combat biofilm-related microbial infections, several strategies have been developed to independently eliminate biofilms or to complement conventional antibiotic therapies. However, their limitations leave room for other treatment alternatives, where the application of nanotechnology to biofilm eradication has gained significant relevance in recent years. Their small size, penetration efficiency, and the design flexibility that they present makes them a promising alternative for biofilm infection treatment, although they also present set-backs. This review aims to describe the main possibilities and limitations of nanomedicine against biofilms, while covering the main aspects of biofilm formation and study, and the current therapies for biofilm treatment. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.}, } @article {pmid38403400, year = {2024}, author = {Qiao, J and Hu, A and Zhou, H and Lu, Z and Meng, F and Shi, C and Bie, X}, title = {Drug-loaded lipid nanoparticles improve the removal rates of the Staphylococcus aureus biofilm.}, journal = {Biotechnology journal}, volume = {19}, number = {2}, pages = {e2300159}, doi = {10.1002/biot.202300159}, pmid = {38403400}, issn = {1860-7314}, support = {2018YFC1602500//National Key R&D Program of China/ ; 31972174//National Natural Science Foundation of China/ ; RC20552139//Start-up Funds for Scientific Research/ ; }, abstract = {Biofilms of the foodborne pathogen Staphylococcus aureus show improved resistance to antibiotics and are difficult to eliminate. To enhance antibacteria and biofilm dispersion via extracellular matrix diffusion, a new lipid nanoparticle was prepared, which employed a mixture of phospholipids and a 0.8% surfactin shell. In the lipid nanoparticle, 31.56 μg mL[-1] of erythromycin was encapsulated. The lipid nanoparticle size was approximately 52 nm and the zeta-potential was -67 mV, which was measured using a Marvin laser particle size analyzer. In addition, lipid nanoparticles significantly dispersed the biofilms of S. aureus W1, CICC22942, and CICC 10788 on the surface of stainless steel, reducing the total viable count of bacteria in the biofilms by 10[3] CFU mL[-1] . In addition, the lipid nanoparticle can remove polysaccharides and protein components from the biofilm matrix. The results of laser confocal microscopy showed that the lipid nanoparticles effectively killed residual bacteria in the biofilms. Thus, to thoroughly eliminate biofilms on material surfaces in food factories to avoid repeated contamination, drug-lipid nanoparticles present a suitable method to achieve this.}, } @article {pmid38403363, year = {2024}, author = {MacConnell, AE and Levack, AE and Brown, NM}, title = {Biofilm and How It Relates to Prosthetic Joint Infection.}, journal = {The Orthopedic clinics of North America}, volume = {55}, number = {2}, pages = {161-169}, doi = {10.1016/j.ocl.2023.10.001}, pmid = {38403363}, issn = {1558-1373}, abstract = {Prosthetic joint infection following total joint arthroplasty is a devastating complication, resulting in increased morbidity and mortality for the patient. The formation of a biofilm on implanted hardware contributes to the difficulty in successful identification and eradication of the infection. Antibiotic therapy and surgical intervention are necessary for addressing this condition; we present a discussion on different treatment options, including those that are not yet routinely utilized in the clinical setting or are under investigation, to highlight the present and future of PJI management.}, } @article {pmid38402970, year = {2024}, author = {Saygin, H and Tilkili, B and Karniyarik, S and Baysal, A}, title = {Culture dependent analysis of bacterial activity, biofilm-formation and oxidative stress of seawater with the contamination of microplastics under climate change consideration.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {171103}, doi = {10.1016/j.scitotenv.2024.171103}, pmid = {38402970}, issn = {1879-1026}, abstract = {Temperature changes due to climate change and microplastic contamination are worldwide concerns, creating various problems in the marine environment. Therefore, this study was carried out to discover the impact of different temperature of seawater exposed to different types of plastic materials on culture dependent bacterial responses and oxidative characteristics. Seawater was exposed to microplastics obtained from various plastic materials at different temperature (-18, +4, +20, and +35 °C) for seven days. Then microplastics were removed from the suspension and microplastic-exposed seawater samples were analyzed for bacterial activity, biofilm formation and oxidative characteristics (antioxidant, catalase, glutathione, and superoxide dismutase) using Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. The results showed that the activity and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus were affected through oxidative stress by catalase, glutathione, and superoxide dismutase due to the microplastic deformation by temperature changes. This study confirms that temperature changes as a result of climate change might influence microplastic degradation and their contamination impact in seawater in terms of bacterial metabolic and oxidation reactions.}, } @article {pmid38402146, year = {2024}, author = {Alshaikh, SA and El-Banna, T and Sonbol, F and Farghali, MH}, title = {Correlation between antimicrobial resistance, biofilm formation, and virulence determinants in uropathogenic Escherichia coli from Egyptian hospital.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {23}, number = {1}, pages = {20}, pmid = {38402146}, issn = {1476-0711}, abstract = {BACKGROUND: Uropathogenic Escherichia coli (UPEC) is the main etiological agent behind community-acquired and hospital-acquired urinary tract infections (UTIs), which are among the most prevalent human infections. The management of UPEC infections is becoming increasingly difficult owing to multi-drug resistance, biofilm formation, and the possession of an extensive virulence arsenal. This study aims to characterize UPEC isolates in Tanta, Egypt, with regard to their antimicrobial resistance, phylogenetic profile, biofilm formation, and virulence, as well as the potential associations among these factors.

METHODS: One hundred UPEC isolates were obtained from UTI patients in Tanta, Egypt. Antimicrobial susceptibility was assessed using the Kirby-Bauer method. Extended-spectrum β-lactamases (ESBLs) production was screened using the double disk synergy test and confirmed with PCR. Biofilm formation was evaluated using the microtiter-plate assay and microscopy-based techniques. The phylogenetic groups of the isolates were determined. The hemolytic activity, motility, siderophore production, and serum resistance of the isolates were also evaluated. The clonal relatedness of the isolates was assessed using ERIC-PCR.

RESULTS: Isolates displayed elevated resistance to cephalosporins (90-43%), sulfamethoxazole-trimethoprim (63%), and ciprofloxacin (53%). Ninety percent of the isolates were multidrug-resistant (MDR)/ extensively drug-resistant (XDR) and 67% produced ESBLs. Notably, there was an inverse correlation between biofilm formation and antimicrobial resistance, and 31%, 29%, 32%, and 8% of the isolates were strong, moderate, weak, and non-biofilm producers, respectively. Beta-hemolysis, motility, siderophore production, and serum resistance were detected in 64%, 84%, 65%, and 11% of the isolates, respectively. Siderophore production was correlated to resistance to multiple antibiotics, while hemolysis was more prevalent in susceptible isolates and associated with stronger biofilms. Phylogroups B2 and D predominated, with lower resistance and stronger biofilms in group B2. ERIC-PCR revealed considerable diversity among the isolates.

CONCLUSION: This research highlights the dissemination of resistance in UPEC in Tanta, Egypt. The evident correlation between biofilm and resistance suggests a resistance cost on bacterial cells; and that isolates with lower resistance may rely on biofilms to enhance their survival. This emphasizes the importance of considering biofilm formation ability during the treatment of UPEC infections to avoid therapeutic failure and/or infection recurrence.}, } @article {pmid38402083, year = {2024}, author = {Wang, Z and Vanbever, R and Lorent, JH and Solis, J and Knoop, C and Van Bambeke, F}, title = {Repurposing DNase I and alginate lyase to degrade the biofilm matrix of dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa grown in artificial sputum medium: In-vitro assessment of their activity in combination with broad-spectrum antibiotics.}, journal = {Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jcf.2024.02.012}, pmid = {38402083}, issn = {1873-5010}, abstract = {BACKGROUND: Biofilm-associated pulmonary infections pose therapeutic challenges in cystic fibrosis patients, especially when involving multiple bacterial species. Enzymatic degradation of the biofilm matrix may offer a potential solution to enhance antibiotic efficacy. This study investigated the repurposing of DNase I, commonly used for its mucolytic activity in cystic fibrosis, to target extracellular DNA within biofilms, as well as potential synergies with alginate lyase and broad-spectrum antibiotics in dual-species biofilms of Pseudomonas aeruginosa and Staphylococcus aureus.

METHODS: Dual-species biofilms were grown in artificial sputum medium using S. aureus and P. aeruginosa isolated by pairs from the same patients and exposed to various combinations of enzymes, meropenem, or tobramycin. Activity was assessed by measuring biofilm biomass and viable counts. Matrix degradation and decrease in bacterial load were visualized using confocal microscopy. Biofilm viscoelasticity was estimated by rheology.

RESULTS: Nearly complete destruction of the biofilms was achieved only if combining the enzymatic cocktail with the two antibiotics, and if using supratherapeutic levels of DNase I and high concentrations of alginate lyase. Biofilms containing non-pigmented mucoid P. aeruginosa required higher antibiotic concentrations, despite low viscoelasticity. In contrast, for biofilms with pigmented mucoid P. aeruginosa, a correlation was observed between the efficacy of different treatments and the reduction they caused in elasticity and viscosity of the biofilm.

CONCLUSIONS: In this complex, highly drug-tolerant biofilm model, enzymes prove useful adjuvants to enhance antibiotic activity. However, the necessity for high enzyme concentrations emphasizes the need for thorough concentration-response evaluations and safety assessments before considering clinical applications.}, } @article {pmid38401619, year = {2024}, author = {Higuera-Rueda, CA and Piuzzi, NS and Milbrandt, NB and Tsai, YH and Klika, AK and Samia, ACS and Visperas, A}, title = {The Mark Coventry Award: PhotothermAA Gel Combined with Debridement, Antibiotics, and Implant Retention (DAIR) Significantly Decreases Implant Biofilm Burden and Soft-Tissue Infection in a Rabbit Model of Knee Periprosthetic Joint Infection.}, journal = {The Journal of arthroplasty}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.arth.2024.02.044}, pmid = {38401619}, issn = {1532-8406}, abstract = {BACKGROUND: Chronic periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. The underlying pathogenesis often involves the formation of bacterial biofilm that protects the pathogen from both host immune responses and antibiotics. The gold standard treatment requires implant removal, a procedure that carries associated morbidity and mortality risks. Strategies to preserve the implant while treating PJI are desperately needed. Our group has developed an anti-biofilm treatment, PhotothermAA gel, that has shown complete eradication of two-week-old mature biofilm in vitro. In this study, we tested the anti-biofilm efficacy and safety of PhotothermAA in vivo when combined with debridement, antibiotics, and implant retention (DAIR) in a rabbit model of knee PJI.

METHODS: New Zealand white rabbits (n = 21) underwent knee joint arthrotomy, titanium tibial implant insertion, and inoculation with Xen36 (bioluminescent Staphylococcus aureus) after capsule closure. At two weeks, rabbits underwent sham surgery (n = 6), DAIR (n = 6), or PhotothermAA with DAIR (n = 9) and were sacrificed two weeks later to measure implant biofilm burden, soft-tissue infection, and tissue necrosis.

RESULTS: The combination of anti-biofilm PhotothermAA with DAIR significantly decreased implant biofilm coverage via scanning electron microscopy compared to DAIR alone (1.8 versus 81.0%; P < 0.0001). Periprosthetic soft-tissue cultures were significantly decreased in the PhotothermAA with DAIR treatment group (log reduction: Sham 1.6, DAIR 2.0, combination 5.6; P < 0.0001). Treatment-associated necrosis was absent via gross histology of tissue adjacent to the treatment area (P = 0.715).

CONCLUSION: The addition of an anti-biofilm solution like PhotothermAA as a supplement to current treatments that allow implant retention may prove useful in PJI treatment.}, } @article {pmid38401436, year = {2024}, author = {Jiang, H and Fang, W and Xu, S and Luo, H and Li, D and Liu, Y and Zeng, Z and Tong, Y and Zhao, L}, title = {Synergistic quorum sensing inhibition and mild-temperature photothermal therapy of integrated nanoplatform for implant-associated biofilm infections.}, journal = {Journal of colloid and interface science}, volume = {663}, number = {}, pages = {143-156}, doi = {10.1016/j.jcis.2024.02.155}, pmid = {38401436}, issn = {1095-7103}, abstract = {In current clinical practice, the presence of biofilms poses a significant challenge in the effective elimination of bacterial infections because of the physical and chemical barriers formed by biofilms, which offer persistent protection to bacteria. Here, we developed hollow mesoporous polydopamine (hMP) nanoparticles (NPs) loaded with luteolin (Lu) as a quorum sensing inhibitor, which were further coated with hyaluronic acid (HA) shells to create hMP-Lu@HA NPs. We observed that upon reaching the infection site, the HA shells underwent initial degradation by the hyaluronidase enzyme present in the bacterial infection's microenvironment to expose the hMP-Lu NPs. Subsequently, Lu was released in response to the acidic conditions characteristic of bacterial infections, which effectively hindered and dispersed the biofilm. Moreover, when subjected to near-infrared irradiation, the robust photothermal conversion effect of hMP NPs accelerated the release of Lu and disrupted the integrity of the biofilms by localized heating. This dual action enhanced the eradication of the biofilm infection. Importantly, hMP-Lu@HA NPs also promoted tissue regeneration and healing at the implantation site, concurrently addressing biofilm infection. Taken together, this nanosystem, combined with mild-temperature photothermal therapy and quorum sensing inhibition strategy, holds significant potential for applications in the treatment of implantation-associated infections.}, } @article {pmid38401380, year = {2024}, author = {Miller, LA and Buckingham-Meyer, K and Goeres, DM}, title = {Simulated aging of draught beer line tubing increases biofilm contamination.}, journal = {International journal of food microbiology}, volume = {415}, number = {}, pages = {110630}, doi = {10.1016/j.ijfoodmicro.2024.110630}, pmid = {38401380}, issn = {1879-3460}, abstract = {Craft brewing is continually gaining popularity in the United States. Craft brewers are committed to producing a wide variety of products and have a vested interest in product quality. Therefore, these brewers have the expectation that the beer poured at the tap will match the quality product that left the brewery. The presence of biofilm in draught lines is hypothesized as a contributing factor when this expectation is not achieved. Clean in place strategies based on the Sinner's Circle of Cleaning are used to remediate organic and inorganic accumulation in beer draught lines, including controlling biofilm accumulation. A study was conducted to determine if repeated exposure to chemical cleaning of vinyl beer tubing impacted biofilm growth, kill/removal, and subsequent regrowth of a mixed species biofilm. The tubing was conditioned to simulate one, two, and five years of use. The data collected demonstrates a clear trend between simulated age of the tubing and biofilm accumulation on the surface. Bacterial log densities ranged from 5.6 Log10(CFU/cm[2]) for the new tubing to 6.6 Log10(CFU/cm[2]) for tubing aged to simulate five years of use. The counts for the yeast were similar. Caustic cleaning of the tubing, regardless of starting biofilm coverage, left less than 2.75 Log10(CFU/cm[2]) viable bacteria and yeast cells remaining on the tubing surface. This demonstrated the effectiveness of the caustic at controlling biofilm accumulation in the simulated beer draught line. The biofilm that accumulated in the five-year aged tubing was able to recover more quickly, reaching 3.6 Log10(CFU/cm[2]) within 24 h indicating the treatment did not fully eradicate the biofilm, suggesting that the strong chemistry used in this study would cease to be as effective over time.}, } @article {pmid38401210, year = {2024}, author = {Liang, C and Svendsen, SB and de Jonge, N and Carvalho, PN and Nielsen, JL and Bester, K}, title = {Eat seldom is better than eat frequently: Pharmaceuticals degradation kinetics, enantiomeric profiling and microorganisms in moving bed biofilm reactors are affected by feast famine cycle times.}, journal = {Journal of hazardous materials}, volume = {468}, number = {}, pages = {133739}, doi = {10.1016/j.jhazmat.2024.133739}, pmid = {38401210}, issn = {1873-3336}, abstract = {Feast-famine (FF) regimes improved the removal of recalcitrant pharmaceuticals in moving bed biofilm reactors (MBBRs), but the optimal FF cycle remained unresolved. The effects of FF cycle time on the removal of bulk substrates (organic carbon and nitrogen) and trace pharmaceuticals by MBBR are systematically evaluated in this study. The feast to famine ratio was fixed to 1:2 to keep the same loading rate, but the time for the FF cycles varied from 18 h to 288 h. The MBBR adapted to the longest FF cycle time (288 h equaling 48 × HRT) resulted in significantly higher degradation rates (up to +183%) for 12 out of 28 pharmaceuticals than a continuously fed (non-FF) reactor. However, other FF cycle times (18, 36, 72 and 144 h) only showed a significant up-regulation for 2-3 pharmaceuticals compared to the non-FF reactor. Enantioselective degradation of metoprolol and propranolol occurred in the second phase of a two phase degradation, which was different for the longer FF cycle time. N-oxidation and N-demethylation pathways of tramadol and venlafaxine differed across the FF cycle time suggestin the FF cycle time varied the predominant transformation pathways of pharmaceuticals. The abundance of bacteria in the biofilms varied considerably between different FF cycle times, which possibly caused the biofilm to remove more recalcitrant bulk organic C and pharmaceuticals under long cycle times.}, } @article {pmid38399762, year = {2024}, author = {Zhang, YG and Zhang, T and Lin, L}, title = {Identification of Flo11-like Adhesin in Schizosaccharomyces pombe and the Mechanism of Small-Molecule Compounds Mediating Biofilm Formation in Yeasts.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020358}, pmid = {38399762}, issn = {2076-2607}, support = {42176211//National Natural Science Foundation of China/ ; }, abstract = {Fungal infection is initiated by the adhesion of pathogens to biotic and abiotic surfaces, with various manifestations including biofilm formation and invasive growth, etc. A previous report, though devoid of functional data, speculated that the Schizosaccharomyces pombe glycoprotein SPBPJ4664.02 could be the homology of Saccharomyces cerevisiae Flo11. Here, our studies with S. pombe substantiated the previously proposed speculation by (1) the deletion of SPBPJ4664.02 attenuated biofilm formation and invasive growth in S. pombe; (2) the S. pombe's lack of SPBPJ4664.02 could be complemented by expressing S. cerevisiae flo11. Furthermore, indole-3-acetic acid (IAA) and dodecanol were examined in S. pombe for their respective effects on biofilm formation. IAA and dodecanol at high concentrations could inhibit biofilm formation, whereas opposing effects were observed with low concentrations of these molecules. Mechanism studies with the SPBPJ4664.02Δ and SPBPJ4664.02Δ/flo11[OE] versus the wild type have demonstrated that IAA or dodecanol might exert regulatory effects downstream of SPBPJ4664.02 in the signaling pathway for biofilm formation. Moreover, our research extrapolated to Candida albicans has pinpointed that IAA inhibited biofilm formation at high concentrations, consistent with the transcriptional downregulation of the biofilm-related genes. Dodecanol suppressed C. albicans biofilm formation at all the concentrations tested, in accord with the downregulation of biofilm-related transcripts.}, } @article {pmid38399697, year = {2024}, author = {Ong, ZX and Kannan, B and Phillips, ARJ and Becker, DL}, title = {Investigation of Staphylococcus aureus Biofilm-Associated Toxin as a Potential Squamous Cell Carcinoma Therapeutic.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020293}, pmid = {38399697}, issn = {2076-2607}, support = {2019-T1-001-126//Minestry of education Tier 1 grant/ ; }, abstract = {Cancer therapies developed using bacteria and their components have been around since the 19th century. Compared to traditional cancer treatments, the use of bacteria-derived compounds as cancer therapeutics could offer a higher degree of specificity, with minimal off-target effects. Here, we explored the use of soluble bacteria-derived toxins as a potential squamous cell carcinoma (SCC) therapeutic. We optimized a protocol to generate Staphylococcus aureus biofilm-conditioned media (BCM), where soluble bacterial products enriched in the development of biofilms were isolated from a bacterial culture and applied to SCC cell lines. Bioactive components of S. aureus ATCC 29213 (SA29213) BCM display selective toxicity towards cancerous human skin SCC-12 at low doses, while non-cancerous human keratinocyte HaCaT and fibroblast BJ-5ta are minimally affected. SA29213 BCM treatment causes DNA damage to SCC-12 and initiates Caspase 3-dependent-regulated cell death. The use of the novel SA29213 bursa aurealis transposon mutant library led to the identification of S. aureus alpha hemolysin as the main bioactive compound responsible for the observed SCC-12-specific toxicity. The antibody neutralisation of Hla eradicates the cytotoxicity of SA29213 BCM towards SCC-12. Hla displays high SCC-12-specific toxicity, which is exerted primarily through Hla-ADAM10 interaction, Hla oligomerisation, and pore formation. The high target specificity and potential to cause cell death in a controlled manner highlight SA29213 Hla as a good candidate as an alternative SCC therapeutic.}, } @article {pmid38399687, year = {2024}, author = {Calderón, IL and Barros, MJ and Fernández-Navarro, N and Acuña, LG}, title = {Detection of Nucleic Acids of the Fish Pathogen Yersinia ruckeri from Planktonic and Biofilm Samples with a CRISPR/Cas13a-Based Assay.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020283}, pmid = {38399687}, issn = {2076-2607}, support = {11201070//Agencia Nacional de Investigación y Desarrollo/ ; 1221610//Agencia Nacional de Investigación y Desarrollo/ ; }, abstract = {Yersinia ruckeri is the cause of hemorrhagic septicemia, known as enteric redmouth disease, in salmonid fish species. This bacterial pathogen can form biofilms on abiotic surfaces of aquaculture settings or even on the surfaces of the fish themselves, contributing to their persistence in the aquatic environment. Detection methods for this and other fish pathogens can be time-consuming and lack specificity and sensitivity, limiting timely monitoring, the treatment of microbial infections, and effective control of their transmission in aquaculture settings. Rapid and sensitive detection methods for nucleic acids can be crucial for an appropriate surveillance of bacterial pathogens, and the CRISPR/Cas-based assays have emerged as a good alternative since it has been proven to be a useful tool for the rapid, specific, and sensitive detection of viruses and some bacteria. In this study, we explored the capability of the CRISPR/Cas13a system (SHERLOCK) to specifically detect both DNA and RNA (gene transcripts) from planktonic and biofilm samples of the bacterial fish pathogen Y. ruckeri. The assay was designed to detect the gyrA gene and the small noncoding RNAs (sRNAs) MicA and RprA from planktonic cultures and biofilm samples prepared in marine broth. The specific crRNA designed for these gene targets included a 28 nt specific gene sequence, and a scaffold sequence necessary for Cas13-binding. For all the assays, the nucleic acids obtained from samples were previously subjected to isothermal amplification with the recombinase polymerase amplification (RPA) method and the subsequent T7 transcription of the RPA amplicons. Finally, the detection of nucleic acids of Y. ruckeri was by means of a reporter signal released by the Cas13a collateral RNA cleavage triggered upon target recognition, measured by fluorescence- or lateral-flow-based readouts. This CRISPR/Cas13a-based assay was able to specifically detect both DNA and sRNAs from the Y. ruckeri samples, and the sensitivity was comparable to that obtained with qPCR analysis, highlighting the potential applicability of this CRISPR/Cas13a-based assay for fish pathogen surveillance.}, } @article {pmid38399673, year = {2024}, author = {Dietrich, M and Besser, M and Stuermer, EK}, title = {Characterization of the Human Plasma Biofilm Model (hpBIOM) to Identify Potential Therapeutic Targets for Wound Management of Chronic Infections.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020269}, pmid = {38399673}, issn = {2076-2607}, abstract = {The treatment of chronic wounds still represents a major challenge in wound management. Recent estimates suggest that 60-80% of chronic wounds are colonized by pathogenic microorganisms, which are strongly considered to have a major inhibiting influence on the healing process. By means of an innovative biofilm model based on human plasma, the time-dependent behavior of various bacterial strains under wound-milieu-like conditions were investigated, and the growth habits of different cocci species were compared. Undescribed fusion events between colonies of MRSA as well as of Staphylococcus epidermidis were detected, which were associated with the remodeling and reorganization of the glycocalyx of the wound tissue. After reaching a maximum colony size, the spreading of individual bacteria was observed. Interestingly, the combination of different cocci species with Pseudomonas aeruginosa in the human plasma biofilm revealed partial synergistic effects in these multispecies organizations. RT-qPCR analyses gave a first impression of the relevant proteins involved in the formation and maturation of biofilms, especially the role of fibrinogen-binding proteins. Knowledge of the maturation and growth behavior of persistent biofilms investigated in a translational human biofilm model reflects a starting point for the development of novel tools for the treatment of chronic wounds.}, } @article {pmid38399660, year = {2024}, author = {Wang, Z and Wang, H and Bai, J and Cai, S and Qu, D and Xie, Y and Wu, Y}, title = {The Staphylococcus aureus ArlS Kinase Inhibitor Tilmicosin Has Potent Anti-Biofilm Activity in Both Static and Flow Conditions.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020256}, pmid = {38399660}, issn = {2076-2607}, support = {81991532, 82072249 and 81671982//National Natural Science Foundation of China/ ; }, abstract = {Staphylococcus aureus can form biofilms on biotic surfaces or implanted materials, leading to biofilm-associated diseases in humans and animals that are refractory to conventional antibiotic treatment. Recent studies indicate that the unique ArlRS regulatory system in S. aureus is a promising target for screening inhibitors that may eradicate formed biofilms, retard virulence and break antimicrobial resistance. In this study, by screening in the library of FDA-approved drugs, tilmicosin was found to inhibit ArlS histidine kinase activity (IC50 = 1.09 μM). By constructing a promoter-fluorescence reporter system, we found that tilmicosin at a concentration of 0.75 μM or 1.5 μM displayed strong inhibition on the expression of the ArlRS regulon genes spx and mgrA in the S. aureus USA300 strain. Microplate assay and confocal laser scanning microscopy showed that tilmicosin at a sub-minimal inhibitory concentration (MIC) had a potent inhibitory effect on biofilms formed by multiple S. aureus strains and a strong biofilm-forming strain of S. epidermidis. In addition, tilmicosin at three-fold of MIC disrupted USA300 mature biofilms and had a strong bactericidal effect on embedded bacteria. Furthermore, in a BioFlux flow biofilm assay, tilmicosin showed potent anti-biofilm activity and synergized with oxacillin against USA300.}, } @article {pmid38399647, year = {2024}, author = {Javed, MQ and Kovalchuk, I and Yevtushenko, D and Yang, X and Stanford, K}, title = {Relationship between Desiccation Tolerance and Biofilm Formation in Shiga Toxin-Producing Escherichia coli.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020243}, pmid = {38399647}, issn = {2076-2607}, support = {FOS.01.17//Beef Cattle Research Council/ ; 2021R014R//Results-Driven Agricultural Research/ ; }, abstract = {Shiga toxin-producing Escherichia coli (STEC) is a major concern in the food industry and requires effective control measures to prevent foodborne illnesses. Previous studies have demonstrated increased difficulty in the control of biofilm-forming STEC. Desiccation, achieved through osmotic stress and water removal, has emerged as a potential antimicrobial hurdle. This study focused on 254 genetically diverse E. coli strains collected from cattle, carcass hides, hide-off carcasses, and processing equipment. Of these, 141 (55.51%) were STEC and 113 (44.48%) were generic E. coli. The biofilm-forming capabilities of these isolates were assessed, and their desiccation tolerance was investigated to understand the relationships between growth temperature, relative humidity (RH), and bacterial survival. Only 28% of the STEC isolates had the ability to form biofilms, compared to 60% of the generic E. coli. Stainless steel surfaces were exposed to different combinations of temperature (0 °C or 35 °C) and relative humidity (75% or 100%), and the bacterial attachment and survival rates were measured over 72 h and compared to controls. The results revealed that all the strains exposed to 75% relative humidity (RH) at any temperature had reduced growth (p < 0.001). In contrast, 35 °C and 100% RH supported bacterial proliferation, except for isolates forming the strongest biofilms. The ability of E. coli to form a biofilm did not impact growth reduction at 75% RH. Therefore, desiccation treatment at 75% RH at temperatures of 0 °C or 35 °C holds promise as a novel antimicrobial hurdle for the removal of biofilm-forming E. coli from challenging-to-clean surfaces and equipment within food processing facilities.}, } @article {pmid38399635, year = {2024}, author = {Vilas Boas, D and Castro, J and Araújo, D and Nóbrega, FL and Keevil, CW and Azevedo, NF and Vieira, MJ and Almeida, C}, title = {The Role of Flagellum and Flagellum-Based Motility on Salmonella Enteritidis and Escherichia coli Biofilm Formation.}, journal = {Microorganisms}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/microorganisms12020232}, pmid = {38399635}, issn = {2076-2607}, support = {PTDC/CVT-CVT/4620/2021//Fundação para a Ciência e a Tecnologia/ ; UIDB/04469/2020//Fundação para a Ciência e Tecnologia/ ; LA/P/0029/2020//Fundação para a Ciência e a Tecnologia/ ; LA/P/0045/2020//FCT/MCTES/ ; UIDB/00511/2020//FCT/MCTES/ ; }, abstract = {Flagellum-mediated motility has been suggested to contribute to virulence by allowing bacteria to colonize and spread to new surfaces. In Salmonella enterica and Escherichia coli species, mutants affected by their flagellar motility have shown a reduced ability to form biofilms. While it is known that some species might act as co-aggregation factors for bacterial adhesion, studies of food-related biofilms have been limited to single-species biofilms and short biofilm formation periods. To assess the contribution of flagella and flagellum-based motility to adhesion and biofilm formation, two Salmonella and E. coli mutants with different flagellar phenotypes were produced: the fliC mutants, which do not produce flagella, and the motAB mutants, which are non-motile. The ability of wild-type and mutant strains to form biofilms was compared, and their relative fitness was determined in two-species biofilms with other foodborne pathogens. Our results showed a defective and significant behavior of E. coli in initial surface colonization (p < 0.05), which delayed single-species biofilm formation. Salmonella mutants were not affected by the ability to form biofilm (p > 0.05). Regarding the effect of motility/flagellum absence on bacterial fitness, none of the mutant strains seems to have their relative fitness affected in the presence of a competing species. Although the absence of motility may eventually delay initial colonization, this study suggests that motility is not essential for biofilm formation and does not have a strong impact on bacteria's fitness when a competing species is present.}, } @article {pmid38399370, year = {2024}, author = {Soontarach, R and Srimanote, P and Voravuthikunchai, SP and Chusri, S}, title = {Antibacterial and Anti-Biofilm Efficacy of Endolysin LysAB1245 against a Panel of Important Pathogens.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {17}, number = {2}, pages = {}, doi = {10.3390/ph17020155}, pmid = {38399370}, issn = {1424-8247}, support = {N41A640071//the National Research Council of Thailand/ ; //the Postdoctoral Fellowship from Prince of Songkla University, Thailand/ ; }, abstract = {Infections caused by antibiotic-resistant bacteria pose a significant global challenge. This study explores the antibacterial effects of a bacteriophage-derived endolysin, LysAB1245, against important pathogens, including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. We determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) for all tested isolates. A time-kill study was conducted to evaluate the reduction in bacterial survival following treatment with LysAB1245. Additionally, the effects of LysAB1245 on P. aeruginosa K1455 and methicillin-resistant S. aureus (MRSA) NPRC 001R-formed biofilms were investigated. The MIC and MBC of LysAB1245 against all the tested isolates ranged from 4.68 to 9.36 µg/mL and 4.68 to 18.72 µg/mL, respectively. The time-kill study demonstrated more than a 4 log CFU/mL (99.99%) reduction in bacterial survival within 6 h of LysAB1245 treatment at 2MIC. LysAB1245 (1/8-1/2MIC) treatment significantly reduced biofilms formed by P. aeruginosa and MRSA in a concentration-dependent manner. Furthermore, scanning electron and confocal laser scanning microscopy confirmed the potential inhibition effects on 3-day established biofilms formed on abiotic surfaces upon treatment with LysAB1245 at 2MIC. The findings indicate that endolysin LysAB1245 could be employed as a new alternative therapeutic antibacterial and anti-biofilm agent for combating biofilm-related infections.}, } @article {pmid38399223, year = {2024}, author = {Damyanova, T and Dimitrova, PD and Borisova, D and Topouzova-Hristova, T and Haladjova, E and Paunova-Krasteva, T}, title = {An Overview of Biofilm-Associated Infections and the Role of Phytochemicals and Nanomaterials in Their Control and Prevention.}, journal = {Pharmaceutics}, volume = {16}, number = {2}, pages = {}, doi = {10.3390/pharmaceutics16020162}, pmid = {38399223}, issn = {1999-4923}, support = {KP-06-H41/8//National Science Fund at the Ministry of Education and Science, Bulgaria/ ; }, abstract = {Biofilm formation is considered one of the primary virulence mechanisms in Gram-positive and Gram-negative pathogenic species, particularly those responsible for chronic infections and promoting bacterial survival within the host. In recent years, there has been a growing interest in discovering new compounds capable of inhibiting biofilm formation. This is considered a promising antivirulence strategy that could potentially overcome antibiotic resistance issues. Effective antibiofilm agents should possess distinctive properties. They should be structurally unique, enable easy entry into cells, influence quorum sensing signaling, and synergize with other antibacterial agents. Many of these properties are found in both natural systems that are isolated from plants and in synthetic systems like nanoparticles and nanocomposites. In this review, we discuss the clinical nature of biofilm-associated infections and some of the mechanisms associated with their antibiotic tolerance. We focus on the advantages and efficacy of various natural and synthetic compounds as a new therapeutic approach to control bacterial biofilms and address multidrug resistance in bacteria.}, } @article {pmid38399044, year = {2024}, author = {Kennewell, TL and Haidari, H and Mashtoub, S and Howarth, GS and Bennett, C and Cooksley, CM and Wormald, PJ and Cowin, AJ and Vreugde, S and Kopecki, Z}, title = {Deferiprone-Gallium-Protoporphyrin Chitogel Decreases Pseudomonas aeruginosa Biofilm Infection without Impairing Wound Healing.}, journal = {Materials (Basel, Switzerland)}, volume = {17}, number = {4}, pages = {}, doi = {10.3390/ma17040793}, pmid = {38399044}, issn = {1996-1944}, support = {Kopecki//Channel 7 Children's Research Foundation/ ; Kopecki//DEBRA Australia/ ; }, abstract = {Pseudomonas aeruginosa is one of the most common pathogens encountered in clinical wound infections. Clinical studies have shown that P. aeruginosa infection results in a larger wound area, inhibiting healing, and a high prevalence of antimicrobial resistance. Hydroxypyridinone-derived iron chelator Deferiprone (Def) and heme analogue Gallium-Protoporphyrin (GaPP) in a chitosan-dextran hydrogel (Chitogel) have previously been demonstrated to be effective against PAO1 and clinical isolates of P. aeruginosa in vitro. Moreover, this combination of these two agents has been shown to improve sinus surgery outcomes by quickly reducing bleeding and preventing adhesions. In this study, the efficacy of Def-GaPP Chitogel was investigated in a P. aeruginosa biofilm-infected wound murine model over 6 days. Two concentrations of Def-GaPP Chitogel were investigated: Def-GaPP high dose (10 mM Def + 500 µg/mL GaPP) and Def-GaPP low dose (5 mM Def + 200 µg/mL GaPP). The high-dose Def-GaPP treatment reduced bacterial burden in vivo from day 2, without delaying wound closure. Additionally, Def-GaPP treatment decreased wound inflammation, as demonstrated by reduced neutrophil infiltration and increased anti-inflammatory M2 macrophage presence within the wound bed to drive wound healing progression. Def-GaPP Chitogel treatment shows promising potential in reducing P. aeruginosa cutaneous infection with positive effects observed in the progression of wound healing.}, } @article {pmid38397912, year = {2024}, author = {Alves, AMCV and de Brito, ÉHS and de Araújo, MFM and de Hollanda Celestino, JJ and Leite, ACRM and Cruz, GS and Azevedo, NF and Rodrigues, CF}, title = {Antifungal Susceptibility and Candida sp. Biofilm Production in Clinical Isolates of HIV-Positive Brazilian Patients under HAART Therapy.}, journal = {Biomedicines}, volume = {12}, number = {2}, pages = {}, doi = {10.3390/biomedicines12020310}, pmid = {38397912}, issn = {2227-9059}, support = {FCT/MCTES (PIDDAC).//LA/P/0045/2020 (ALiCE), UIDB/00511/2020 and UIDP/00511/2020 (LEPABE), funded by national funds through/ ; 60395063//Global Medical Grants/ ; }, abstract = {The aim of the present study was to characterize biofilms formed by Candida spp. clinical isolates (n = 19), isolated from the oral mucosa of HIV-positive patients. For characterizing the biofilms formed by several Candida sp. strains, isolated from HIV-positive patients, in terms of formed biomass, matrix composition and antifungal susceptibility profile, clinical isolates (n = 19) were collected from oral mucosa and identified. The biofilm of the samples was cultured with fluconazole (1250 mg/L), voriconazole (800 mg/L), anidulafungin (2 mg/L) or amphotericin B (2 mg/L). Afterwards, the quantification of the total biomass was performed using crystal violet assay, while the proteins and carbohydrates levels were quantified in the matrix. The results showed a predominance of C. albicans, followed by C. krusei. Around 58% of the Candida spp. biofilm had susceptibility to fluconazole and voriconazole (800 mg/L), 53% to anidulafungin and 74% to amphotericin B. C. krusei presented both the lowest and the highest biofilm matrix contents in polysaccharides and proteins. The low resistance to antifungal agents reported here was probably due to the fact that none of the participants had a prolonged exposure to these antifungals. A predominance of less virulent Candida spp. strains with low or no resistance to antifungals was observed. This can be attributed to a low fungal selective pressure. This most probably happened due to a low fungal selective pressure but also due to a good adherence to HAART therapy, which guarantees a stable and stronger immune patient response.}, } @article {pmid38397843, year = {2024}, author = {Ye, J and Salti, T and Zanditenas, E and Trebicz-Geffen, M and Benhar, M and Ankri, S}, title = {Impact of Reactive Sulfur Species on Entamoeba histolytica: Modulating Viability, Motility, and Biofilm Degradation Capacity.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antiox13020245}, pmid = {38397843}, issn = {2076-3921}, support = {1020546//Ministry of Science and Technology ISRAEL/ ; }, abstract = {Reactive sulfur species (RSS) like hydrogen sulfide (H2S) and cysteine persulfide (Cys-SSH) emerged as key signaling molecules with diverse physiological roles in the body, depending on their concentration and the cellular environment. While it is known that H2S and Cys-SSH are produced by both colonocytes and by the gut microbiota through sulfur metabolism, it remains unknown how these RSS affect amebiasis caused by Entamoeba histolytica, a parasitic protozoan that can be present in the human gastrointestinal tract. This study investigates H2S and Cys-SSH's impact on E. histolytica physiology and explores potential therapeutic implications. Exposing trophozoites to the H2S donor, sodium sulfide (Na2S), or to Cys-SSH led to rapid cytotoxicity. A proteomic analysis of Cys-SSH-challenged trophozoites resulted in the identification of >500 S-sulfurated proteins, which are involved in diverse cellular processes. Functional assessments revealed inhibited protein synthesis, altered cytoskeletal dynamics, and reduced motility in trophozoites treated with Cys-SSH. Notably, cysteine proteases (CPs) were significantly inhibited by S-sulfuration, affecting their bacterial biofilm degradation capacity. Immunofluorescence microscopy confirmed alterations in actin dynamics, corroborating the proteomic findings. Thus, our study reveals how RSS perturbs critical cellular functions in E. histolytica, potentially influencing its pathogenicity and interactions within the gut microbiota. Understanding these molecular mechanisms offers novel insights into amebiasis pathogenesis and unveils potential therapeutic avenues targeting RSS-mediated modifications in parasitic infections.}, } @article {pmid38397101, year = {2024}, author = {Kim, YG and Lee, JH and Kim, SH and Park, SY and Kim, YJ and Ryu, CM and Seo, HW and Lee, JT}, title = {Inhibition of Biofilm Formation in Cutibacterium acnes, Staphylococcus aureus, and Candida albicans by the Phytopigment Shikonin.}, journal = {International journal of molecular sciences}, volume = {25}, number = {4}, pages = {}, doi = {10.3390/ijms25042426}, pmid = {38397101}, issn = {1422-0067}, support = {2021R1I1A3A04037486//National Research Foundation of Korea/ ; 2022R1C1C2006146//Ministry of Science and ICT/ ; 2021R1A2C1008368//Ministry of Science and ICT/ ; }, abstract = {Skin microbiota, such as acne-related Cutibacterium acnes, Staphylococcus aureus, and fungal Candida albicans, can form polymicrobial biofilms with greater antimicrobial tolerance to traditional antimicrobial agents and host immune systems. In this study, the phytopigment shikonin was investigated against single-species and multispecies biofilms under aerobic and anaerobic conditions. Minimum inhibitory concentrations of shikonin were 10 µg/mL against C. acnes, S. aureus, and C. albicans, and at 1-5 µg/mL, shikonin efficiently inhibited single biofilm formation and multispecies biofilm development by these three microbes. Shikonin increased porphyrin production in C. acnes, inhibited cell aggregation and hyphal formation by C. albicans, decreased lipase production, and increased hydrophilicity in S. aureus. In addition, shikonin at 5 or 10 µg/mL repressed the transcription of various biofilm-related genes and virulence-related genes in C. acnes and downregulated the gene expression levels of the quorum-sensing agrA and RNAIII, α-hemolysin hla, and nuclease nuc1 in S. aureus, supporting biofilm inhibition. In addition, shikonin prevented multispecies biofilm development on porcine skin, and the antimicrobial efficacy of shikonin was recapitulated in a mouse infection model, in which it promoted skin regeneration. The study shows that shikonin inhibits multispecies biofilm development by acne-related skin microbes and might be useful for controlling bacterial infections.}, } @article {pmid38395584, year = {2024}, author = {Liu, X and Xia, X and Liu, Y and Li, Z and Shi, T and Zhang, H and Dong, Q}, title = {Recent advances on the formation, detection, resistance mechanism, and control technology of Listeria monocytogenes biofilm in food industry.}, journal = {Food research international (Ottawa, Ont.)}, volume = {180}, number = {}, pages = {114067}, doi = {10.1016/j.foodres.2024.114067}, pmid = {38395584}, issn = {1873-7145}, abstract = {Listeria monocytogenes is an important foodborne pathogen that causes listeriosis, a severe and fatal condition. Biofilms are communities of microorganisms nested within a self-secreted extracellular polymeric substance, and they protect L. monocytogenes from environmental stresses. Biofilms, once formed, can lead to the persistence of L. monocytogenes in processing equipment and are therefore considered to be a major concern for the food industry. This paper briefly introduces the recent advancements on biofilm formation characteristics and detection methods, and focuses on analysis of the mechanism of L. monocytogenes biofilm resistance; Moreover, this paper also summarizes and discusses the existing different techniques of L. monocytogenes biofilm control according to the physical, chemical, biological, and combined strategies, to provide a theoretical reference to aid the choice of effective control technology in the food industry.}, } @article {pmid38395246, year = {2024}, author = {Leite, ML and Comeau, P and Aghakeshmiri, S and Lange, D and Rodrigues, LKA and Branda, N and Manso, AP}, title = {Antimicrobial photodynamic therapy against a dual-species cariogenic biofilm using a ruthenium-loaded resin-based dental material.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {}, number = {}, pages = {104019}, doi = {10.1016/j.pdpdt.2024.104019}, pmid = {38395246}, issn = {1873-1597}, abstract = {BACKGROUND: Streptococcus mutans and Candida albicans are associated with caries recurrence. Therefore, this study evaluated the combination of a Ru(II)-loaded resin-based dental material (RDM) and antimicrobial photodynamic therapy (aPDT) against a dual-species biofilm of S. mutans and C. albicans.

METHODS: An aPDT protocol was established evaluating Ru(II)'s photocatalytic activity and antimicrobial potential under blue LED irradiation (440-460 nm, 22.55 mW/cm[2]) at different energy densities (0.00, 6.25, 20.25, 40.50 J/cm2). This evaluation involved singlet oxygen quantification and determination of minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). The biofilm was grown (72 h) on resin disks prepared with Ru(II)-doped RDM (0.00, 0.56, or 1.12%) and samples were exposed to aPDT or dark conditions. The biofilm was then harvested to analyze cell viability (CFU counts) and formation of soluble and insoluble exopolysaccharides.

RESULTS: The photocatalytic activity of Ru(II) was concentration and energy density dependent (p<0.05), and MIC/MBC values were reduced for the microorganisms after LED irradiation (40.5 J/cm[2]); therefor, this energy density was chosen for aPDT. Although incorporation of Ru(II) into RDM reduced the biofilm growth compared to Ru(II)-free RDM for both species in dark conditions (p<0.05), aPDT combined with an Ru(II)-loaded RDM (0.56 or 1.12%) potentialized CFU reductions (p<0.05). Conversely, only 1.12% Ru(II) with LED irradiation showed lower levels of both soluble and insoluble exopolysaccharides compared to Ru(II)-free samples in dark conditions (p<0.05).

CONCLUSIONS: When the Ru(II)-loaded RDM was associated with blue LED, aPDT reduced cell viability and lower soluble and insoluble exopolysaccharides were found in the cariogenic dual-species biofilm.}, } @article {pmid38394874, year = {2024}, author = {Zhu, S and Zhang, Z and Wen, C and Zhu, S and Li, C and Xu, H and Luo, X}, title = {Transport and transformations of cadmium in water-biofilm-sediment phases as affected by hydrodynamic conditions.}, journal = {Journal of environmental management}, volume = {354}, number = {}, pages = {120368}, doi = {10.1016/j.jenvman.2024.120368}, pmid = {38394874}, issn = {1095-8630}, abstract = {Hydrodynamic conditions play a crucial role in governing the fate, transport, and risks of metal elements. However, the contribution of hydrodynamic conditions to the fate and transport of heavy metals among water, sediment, and biofilm phases is poorly understood. In our study, we conducted experiments in controlled hydrodynamic conditions using a total of 6 two-phase and 9 three-phase mesocosms consisting of water, biofilm, and sediment. We also measured Cd (cadmium) specification in different phases to assess how hydrodynamic forces control Cd bioavailability. We found that turbulent flow destroyed the surface morphology of the biofilm and significantly decreased the content of extracellular polymeric substances (p < 0.05). This led to a decrease in the biofilm's adsorption capacity for Cd, with the maximum adsorption capacity (0.124 mg/g) being one-tenth of that under static conditions (1.256 mg/g). The Cd chemical forms in the biofilm and sediment were significantly different, with the highest amount of Cd in the biofilm being acid-exchangeable, accounting for up to 95.1% of the total Cd content. Cd was more easily released in the biofilm due to its weak binding state, while Cd in the sediment existed in more stable chemical forms. Hydrodynamic conditions altered the migration behavior and distribution characteristics of Cd in the system by changing the adsorption capacity of the biofilm and sediment for Cd. Cd mobility increased in laminar flow but decreased in turbulent flow. These results enhance our understanding of the underlying mechanisms that control the mobility and bioavailability of metals in aquatic environments with varying hydrodynamic conditions.}, } @article {pmid38393852, year = {2024}, author = {Zhou, Q and Fan, S and Lei, KM and Ham, D and Martins, RP and Mak, PI}, title = {Miniature Magnetic Resonance Imaging System for in Situ Monitoring of Bacterial Growth and Biofilm Formation.}, journal = {IEEE transactions on biomedical circuits and systems}, volume = {PP}, number = {}, pages = {}, doi = {10.1109/TBCAS.2024.3369389}, pmid = {38393852}, issn = {1940-9990}, abstract = {In situ monitoring of bacterial growth can greatly benefit human healthcare, biomedical research, and hygiene management. Magnetic resonance imaging (MRI) offers two key advantages in tracking bacterial growth: non-invasive monitoring through opaque sample containers and no need for sample pretreatment such as labeling. However, the large size and high cost of conventional MRI systems are the roadblocks for in situ monitoring. Here, we proposed a small, portable MRI system by combining a small permanent magnet and an integrated radio-frequency (RF) electronic chip that excites and reads out nuclear spin motions in a sample, and utilize this small MRI platform for in situ imaging of bacterial growth and biofilm formation. We demonstrate that MRI images taken by the miniature--and thus broadly deployable for in situ work--MRI system provide information on the spatial distribution of bacterial density, and a sequential set of MRI images taken at different times inform the temporal change of the spatial map of bacterial density, showing bacterial growth.}, } @article {pmid38393446, year = {2024}, author = {Talieh Mostaghimi, and Pournajaf, A and Bijani, A and Mohammadi, M and Rajabnia, M and Halaji, M}, title = {Phylogenetic analysis, biofilm formation, antimicrobial resistance and relationship between these characteristics in Uropathogenic Escherichia coli.}, journal = {Molecular biology reports}, volume = {51}, number = {1}, pages = {327}, pmid = {38393446}, issn = {1573-4978}, abstract = {BACKGROUND: In the present study, we examine the prevalence of phylogenetic groups, O-serogroups, adhesin genes, antimicrobial resistance, the level of gene expression associated with biofilm formation, and the presence of extended-spectrum beta-lactamase (ESBL) in UPEC strains isolated from both pediatric and adult patients.

METHODS: In this cross-sectional study, 156 UPEC isolates were collected from UTI patients. ESBL-producing isolates were detected using the double-disc synergy (DDS) method, and biofilm formation was assessed through a microplate assay. The presence of O-serogroups, adhesion factors and resistance genes, including ESBLs and PMQR genes, was detected by PCR, and isolates were categorized into phylogenetic groups using multiplex PCR. Additionally, the quantitative real-time PCR method was also used to determine the expression level of genes related to biofilm.

RESULTS: During the study period, 50.6% (79/156) of the samples were obtained from children, and 49.4% (77/156) were from adults. The highest rate of resistance was to NA (91.7%), while FM (10.9%) had the lowest rate of antibiotic resistance. In addition, 67.9% (106/156) of UPEC isolates were ESBL producers. Most of UPEC isolates belonged to phylogenetic group B2 (37.1%). This study revealed that blaCTX-M and qnrS are widely distributed among UPEC isolates. The mean expression levels of fimA genes were significantly higher in non-biofilm producers than in biofilm producers (p < 0.01).

CONCLUSIONS: The high antibiotic resistance rates in this study highlight the significance of local resistance monitoring and investigating underlying mechanisms. Our findings indicate the dominance of phylogroup B2 and group D as the prevailing phylogenetic groups. Consequently, it is imperative to investigate the epidemiological aspects and characterize UPEC isolates across diverse regions and time frames.}, } @article {pmid38392909, year = {2024}, author = {Skof, A and Koller, M and Baumert, R and Hautz, J and Treiber, F and Kittinger, C and Zarfel, G}, title = {Comparison of the Antibiotic Resistance of Escherichia coli Populations from Water and Biofilm in River Environments.}, journal = {Pathogens (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/pathogens13020171}, pmid = {38392909}, issn = {2076-0817}, support = {P32464//FWF Austrian Science Fund/ ; }, abstract = {Antibiotic-resistant, facultative pathogenic bacteria are commonly found in surface water; however, the factors influencing the spread and stabilization of antibiotic resistance in this habitat, particularly the role of biofilms, are not fully understood. The extent to which bacterial populations in biofilms or sediments exacerbate the problem for specific antibiotic classes or more broadly remains unanswered. In this study, we investigated the differences between the bacterial populations found in the surface water and sediment/biofilm of the Mur River and the Drava River in Austria. Samples of Escherichia coli were collected from both the water and sediment at two locations per river: upstream and downstream of urban areas that included a sewage treatment plant. The isolates were subjected to antimicrobial susceptibility testing against 21 antibiotics belonging to seven distinct classes. Additionally, isolates exhibiting either extended-spectrum beta-lactamase (ESBL) or carbapenemase phenotypes were further analyzed for specific antimicrobial resistance genes. E. coli isolates collected from all locations exhibited resistance to at least one of the tested antibiotics; on average, isolates from the Mur and Drava rivers showed 25.85% and 23.66% resistance, respectively. The most prevalent resistance observed was to ampicillin, amoxicillin-clavulanic acid, tetracycline, and nalidixic acid. Surprisingly, there was a similar proportion of resistant bacteria observed in both open water and sediment samples. The difference in resistance levels between the samples collected upstream and downstream of the cities was minimal. Out of all 831 isolates examined, 13 were identified as carrying ESBL genes, with 1 of these isolates also containing the gene for the KPC-2 carbapenemase. There were no significant differences between the biofilm (sediment) and open water samples in the occurrence of antibiotic resistance. For the E. coli populations in the examined rivers, the different factors in water and the sediment do not appear to influence the stability of resistance. No significant differences in antimicrobial resistance were observed between the bacterial populations collected from the biofilm (sediment) and open-water samples in either river. The different factors in water and the sediment do not appear to influence the stability of resistance. The minimal differences observed upstream and downstream of the cities could indicate that the river population already exhibits generalized resistance.}, } @article {pmid38392883, year = {2024}, author = {Ma, Z and Xiao, H and Li, H and Lu, X and Yan, J and Nie, H and Yin, Q}, title = {Prodigiosin as an Antibiofilm Agent against the Bacterial Biofilm-Associated Infection of Pseudomonas aeruginosa.}, journal = {Pathogens (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/pathogens13020145}, pmid = {38392883}, issn = {2076-0817}, support = {No.32100139//National Natural Science Foundation of China/ ; No.sl202100000725//The Project of Chongqing Science and Technology Bureau/ ; }, abstract = {Pseudomonas aeruginosa is known to generate bacterial biofilms that increase antibiotic resistance. With the increase of multi-drug resistance in recent years, the formulation of a new therapeutic strategy has seemed urgent. Preliminary findings show that Prodigiosin (PG), derived from chromium-resistant Serratia marcescens, exhibited efficient anti-biofilm activity against Staphylococcus aureus. However, its anti-biofilm activity against P. aeruginosa remains largely unexplored. The anti-biofilm activity of PG against three clinical single drug-resistant P. aeruginosa was evaluated using crystal violet staining, and the viability of biofilms and planktonic cells were also assessed. A model of chronic lung infection was constructed to test the in vivo antibiofilm activity of PG. The results showed that PG inhibited biofilm formation and effectively inhibited the production of pyocyanin and extracellular polysaccharides in vitro, as well as moderated the expression of interleukins (IL-1β, IL-6, IL-10) and tumor necrosis factor (TNF-α) in vivo, which might be attributed to the downregulation of biofilm-related genes such as algA, pelA, and pslM. These findings suggest that PG could be a potential treatment for drug-resistant P aeruginosa and chronic biofilm infections.}, } @article {pmid38392327, year = {2024}, author = {Cavallo, I and Sivori, F and Mastrofrancesco, A and Abril, E and Pontone, M and Di Domenico, EG and Pimpinelli, F}, title = {Bacterial Biofilm in Chronic Wounds and Possible Therapeutic Approaches.}, journal = {Biology}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/biology13020109}, pmid = {38392327}, issn = {2079-7737}, abstract = {Wound repair and skin regeneration is a very complex orchestrated process that is generally composed of four phases: hemostasis, inflammation, proliferation, and remodeling. Each phase involves the activation of different cells and the production of various cytokines, chemokines, and other inflammatory mediators affecting the immune response. The microbial skin composition plays an important role in wound healing. Indeed, skin commensals are essential in the maintenance of the epidermal barrier function, regulation of the host immune response, and protection from invading pathogenic microorganisms. Chronic wounds are common and are considered a major public health problem due to their difficult-to-treat features and their frequent association with challenging chronic infections. These infections can be very tough to manage due to the ability of some bacteria to produce multicellular structures encapsulated into a matrix called biofilms. The bacterial species contained in the biofilm are often different, as is their capability to influence the healing of chronic wounds. Biofilms are, in fact, often tolerant and resistant to antibiotics and antiseptics, leading to the failure of treatment. For these reasons, biofilms impede appropriate treatment and, consequently, prolong the wound healing period. Hence, there is an urgent necessity to deepen the knowledge of the pathophysiology of delayed wound healing and to develop more effective therapeutic approaches able to restore tissue damage. This work covers the wound-healing process and the pathogenesis of chronic wounds infected by biofilm-forming pathogens. An overview of the strategies to counteract biofilm formation or to destroy existing biofilms is also provided.}, } @article {pmid38391928, year = {2024}, author = {Ng, E and Tay, JRH and Mattheos, N and Bostanci, N and Belibasakis, GN and Seneviratne, CJ}, title = {A Mapping Review of the Pathogenesis of Peri-Implantitis: The Biofilm-Mediated Inflammation and Bone Dysregulation (BIND) Hypothesis.}, journal = {Cells}, volume = {13}, number = {4}, pages = {}, doi = {10.3390/cells13040315}, pmid = {38391928}, issn = {2073-4409}, abstract = {This mapping review highlights the need for a new paradigm in the understanding of peri-implantitis pathogenesis. The biofilm-mediated inflammation and bone dysregulation (BIND) hypothesis is proposed, focusing on the relationship between biofilm, inflammation, and bone biology. The close interactions between immune and bone cells are discussed, with multiple stable states likely existing between clinically observable definitions of peri-implant health and peri-implantitis. The framework presented aims to explain the transition from health to disease as a staged and incremental process, where multiple factors contribute to distinct steps towards a tipping point where disease is manifested clinically. These steps might be reached in different ways in different patients and may constitute highly individualised paths. Notably, factors affecting the underlying biology are identified in the pathogenesis of peri-implantitis, highlighting that disruptions to the host-microbe homeostasis at the implant-mucosa interface may not be the sole factor. An improved understanding of disease pathogenesis will allow for intervention on multiple levels and a personalised treatment approach. Further research areas are identified, such as the use of novel biomarkers to detect changes in macrophage polarisation and activation status, and bone turnover.}, } @article {pmid38391673, year = {2024}, author = {Murkar, R and von Heckel, C and Walles, H and Moch, TB and Arens, C and Davaris, N and Weber, A and Zuschratter, W and Baumann, S and Reinhardt, J and Kopp, S}, title = {Establishment of a Human Immunocompetent 3D Tissue Model to Enable the Long-Term Examination of Biofilm-Tissue Interactions.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {11}, number = {2}, pages = {}, doi = {10.3390/bioengineering11020187}, pmid = {38391673}, issn = {2306-5354}, support = {13N15789//Federal Ministry of Education and Research/ ; }, abstract = {Different studies suggest an impact of biofilms on carcinogenic lesion formation in varying human tissues. However, the mechanisms of cancer formation are difficult to examine in vivo as well as in vitro. Cell culture approaches, in most cases, are unable to keep a bacterial steady state without any overgrowth. In our approach, we aimed to develop an immunocompetent 3D tissue model which can mitigate bacterial outgrowth. We established a three-dimensional (3D) co-culture of human primary fibroblasts with pre-differentiated THP-1-derived macrophages on an SIS-muc scaffold which was derived by decellularisation of a porcine intestine. After establishment, we exposed the tissue models to define the biofilms of the Pseudomonas spec. and Staphylococcus spec. cultivated on implant mesh material. After 3 days of incubation, the cell culture medium in models with M0 and M2 pre-differentiated macrophages presented a noticeable turbidity, while models with M1 macrophages presented no noticeable bacterial growth. These results were validated by optical density measurements and a streak test. Immunohistology and immunofluorescent staining of the tissue presented a positive impact of the M1 macrophages on the structural integrity of the tissue model. Furthermore, multiplex ELISA highlighted the increased release of inflammatory cytokines for all the three model types, suggesting the immunocompetence of the developed model. Overall, in this proof-of-principle study, we were able to mitigate bacterial overgrowth and prepared a first step for the development of more complex 3D tissue models to understand the impact of biofilms on carcinogenic lesion formation.}, } @article {pmid38391561, year = {2024}, author = {Smirnov, A and Yanushevich, O and Krikheli, N and Solis Pinargote, NW and Peretyagin, P and Grigoriev, S and Alou, L and Sevillano, D and López-Piriz, R and Guitian, F and Bartolomé, JF}, title = {3Y-TZP/Ta Biocermet as a Dental Material: An Analysis of the In Vitro Adherence of Streptococcus Oralis Biofilm and an In Vivo Pilot Study in Dogs.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020175}, pmid = {38391561}, issn = {2079-6382}, support = {056-00041-23-00//Ministry of Science and Higher Education of the Russian Federation/ ; }, abstract = {The surface adhesion of bacterial cells and the in vivo biocompatibility of a new ceramic-metal composite made of zirconium dioxide and tantalum were evaluated. Within the framework of an in vitro study using the crystal violet staining and colony counting methods, a relatively similar adhesion of Streptococcus oralis to the 3Y-TZP/Ta biocermet (roughness Ra = 0.12 ± 0.04 µm) and Ti-Al6-V4 titanium alloy (Ra = 0.04 ± 0.01 µm) was found. In addition, in an in vivo preliminary study focused on the histological analysis of a series of rods implanted in the jaws of beagle dogs for a six-month period, the absence of any fibrous tissue or inflammatory reaction at the interface between the implanted 3Y-TZP/Ta biocermets and the new bone was found. Thus, it can be concluded that the developed ceramic-metal biocomposite may be a promising new material for use in dentistry.}, } @article {pmid38391556, year = {2024}, author = {Araújo, L and Papa-Ezdra, R and Ávila, P and Iribarnegaray, V and Bado, I and Telechea, H and Garcia-Fulgueiras, V and Vignoli, R}, title = {Great Plasticity in a Great Pathogen: Capsular Types, Virulence Factors and Biofilm Formation in ESBL-Producing Klebsiella pneumoniae from Pediatric Infections in Uruguay.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020170}, pmid = {38391556}, issn = {2079-6382}, support = {46//Comisión Sectorial de Investigación Científica/ ; }, abstract = {Klebsiella pneumoniae is widely recognized as an opportunistic hospital and community pathogen. It is one of the priority microorganisms included in the ESKAPE group, and its antibiotic resistance related to extended-spectrum β-lactamases (ESBL) is a global public health concern. The multi-drug resistance (MDR) phenotype, in combination with pathogenicity factors, could enhance the ability of this pathogen to cause clinical infections. The aim of this study was to characterize pathogenicity factors and biofilm formation in ESBL-producing K. pneumoniae from pediatric clinical infections. Capsular types, virulence factors, and sequence types were characterized by PCR. Biofilm formation was determined by a semiquantitative microtiter technique. MDR phenotype and statistical analysis were performed. The K24 capsular type (27%), virulence factors related to iron uptake fyuA (35%) and kfuBC (27%), and sequence types ST14 (18%) and ST45 (18%) were the most frequently detected. Most of the strains were biofilm producers: weak (22%), moderate (22%), or strong (12%). In 62% of the strains, an MDR phenotype was detected. Strains with K24 capsular type showed an association with ST45 and the presence of fyuA; strains with kfuBC showed an association with moderate or strong biofilm production and belonging to ST14. Weak or no biofilm producers were associated with the absence of kfuBC. The MDR phenotype was associated with the main ESBL gene, blaCTX-M-15. The high plasticity of K. pneumoniae to acquire an MDR phenotype, in combination with the factors exposed in this report, could make it even more difficult to achieve a good clinical outcome with the available therapeutics.}, } @article {pmid38391552, year = {2024}, author = {Nascimento, M and Rodrigues, J and Matias, R and Jordao, L}, title = {Aeromonas spp. in Freshwater Bodies: Antimicrobial Resistance and Biofilm Assembly.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020166}, pmid = {38391552}, issn = {2079-6382}, abstract = {Aeromonas spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in Aeromonas persistence in freshwater. Aeromonas were isolated from water and biofilm samples and identified by Vitek-MS and 16S rRNA sequencing. Antibiotic susceptibility profiles were determined according to EUCAST, and a crystal violet assay was used to assess biofilm assembly. MTT and the enumeration of colony-forming units were used to evaluate biofilm and planktonic Aeromonas susceptibility to chlorination, respectively. Identification at the species level was challenging, suggesting the need to improve the used methodologies. Five different Aeromonas species (A. salmonicida, A. hydrophila, A. media, A. popoffii and A. veronii) were identified from water, and one species was identified from biofilms (A. veronii). A. veronnii and A. salmonicida presented resistance to different antibiotics, whith the highest resistance rate observed for A. salmonicida (multiple antibiotic resistance index of 0.25). Of the 21 isolates, 11 were biofilm producers, and 10 of them were strong biofilm producers (SBPs). The SBPs presented increased tolerance to chlorine disinfection when compared with their planktonic counterparts. In order to elucidate the mechanisms underlying biofilm tolerance to chlorine and support the importance of preventing biofilm assembly in water reservoirs, further research is required.}, } @article {pmid38391533, year = {2024}, author = {Romero, LC and Silva, LP and Teixeira, NB and de Camargo, KV and Del Masso Pereira, MA and Corrente, JE and Pereira, VC and Ribeiro de Souza da Cunha, ML}, title = {Staphylococcus capitis Bloodstream Isolates: Investigation of Clonal Relationship, Resistance Profile, Virulence and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020147}, pmid = {38391533}, issn = {2079-6382}, support = {88887.466764/2019-00//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 88887.613296/2021-00//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 303603/2020-8//National Council for Scientific and Technological Development/ ; }, abstract = {Staphylococcus capitis has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to describe the epidemiological profile of clinical isolates of S. capitis and to characterize the factors involved in the persistence and pathogenesis of these strains isolated from blood cultures collected in a hospital in the interior of the state of São Paulo, Brazil. A total of 141 S. capitis strains were submitted to detection of the mecA gene and SCCmec typing by multiplex PCR. Genes involved in biofilm production and genes encoding enterotoxins and hemolysins were detected by conventional PCR. Biofilm formation was evaluated by the polystyrene plate adherence test and phenotypic resistance was investigated by the disk diffusion method. Finally, pulsed-field gel electrophoresis (PFGE) was used to analyze the clonal relationship between isolates. The mecA gene was detected in 99 (70.2%) isolates, with this percentage reaching 100% in the neonatal ICU. SCCmec type III was the most prevalent type, detected in 31 (31.3%) isolates and co-occurrence of SCCmec was also observed. In vitro biofilm formation was detected in 46 (32.6%) isolates but was not correlated with the presence of the ica operon genes. Furthermore, biofilm production in ICU isolates was favored by hyperosmotic conditions, which are common in ICUs because of the frequent parenteral nutrition. Analysis of the clonal relationship between the isolates investigated in the present study confirms a homogeneous profile of S. capitis and the persistence of clones that are prevalent in the neonatal ICU and disseminated across the hospital. This study highlights the adaptation of isolates to specific hospital environments and their high clonality.}, } @article {pmid38391526, year = {2024}, author = {Barros, AC and Narciso, DAC and Melo, LF and Pereira, A}, title = {Influence of Dead Cells Killed by Industrial Biocides (BAC and DBNPA) on Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020140}, pmid = {38391526}, issn = {2079-6382}, support = {LA/P/0045/2020//Fundação para a Ciência e Tecnologia/ ; UIDP/00511/2020//Fundação para a Ciência e Tecnologia/ ; POCI-01-0247-FEDER-033298//Agencia de Inovacao/ ; Aquatic/0007/2020//Fundação para a Ciência e Tecnologia/ ; SFRH/BD/146028/2019//Fundação para a Ciência e Tecnologia/ ; NORTE-01-0145-FEDER-000069//Fundo Europeu de Desenvolvimento Regional/ ; UIDB/00511/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {Industrial biocides aim to keep water systems microbiologically controlled and to minimize biofouling. However, the resulting dead cells are usually not removed from the water streams and can influence the growth of the remaining live cells in planktonic and sessile states. This study aims to understand the effect of dead Pseudomonas fluorescens cells killed by industrial biocides-benzalkonium chloride (BAC) and 2,2-dibromo-3-nitrilopropionamide (DBNPA)-on biofilm formation. Additionally, the effect of different dead/live cell ratios (50.00% and 99.99%) was studied. The inoculum was recirculated in a Parallel Plate Flow Cell (PPFC). The overall results indicate that dead cells greatly affect biofilm properties. Inoculum with DBNPA-dead cells led to more active (higher ATP content and metabolic activity) and thicker biofilm layers in comparison to BAC-dead cells, which seems to be linked to the mechanism of action by which the cells were killed. Furthermore, higher dead cell ratios (99.99%) in the inoculum led to more active (higher culturability, metabolic activity and ATP content) and cohesive/compact and uniformly distributed biofilms in comparison with the 50.00% dead cell ratio. The design of future disinfection strategies must consider the contribution of dead cells to the biofilm build-up, as they might negatively affect water system operations.}, } @article {pmid38391511, year = {2024}, author = {Gordon, M and Ramirez, P}, title = {Efficacy and Experience of Bacteriophages in Biofilm-Related Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, doi = {10.3390/antibiotics13020125}, pmid = {38391511}, issn = {2079-6382}, abstract = {Bacterial infection has always accompanied human beings, causing suffering and death while also contributing to the advancement of medical science. However, the treatment of infections has become more complex in recent times. The increasing resistance of bacterial strains to antibiotics has diminished the effectiveness of the therapeutic arsenal, making it less likely to find the appropriate empiric antibiotic option. Additionally, the development and persistence of bacterial biofilms have become more prevalent, attributed to the greater use of invasive devices that facilitate biofilm formation and the enhanced survival of chronic infection models where biofilm plays a crucial role. Bacteria within biofilms are less susceptible to antibiotics due to physical, chemical, and genetic factors. Bacteriophages, as biological weapons, can overcome both antimicrobial resistance and biofilm protection. In this review, we will analyze the scientific progress achieved in vitro to justify their clinical application. In the absence of scientific evidence, we will compile publications of clinical cases where phages have been used to treat infections related to biofilm. The scientific basis obtained in vitro and the success rate and safety observed in clinical practice should motivate the medical community to conduct clinical trials establishing a protocol for the proper use of bacteriophages.}, } @article {pmid38390522, year = {2024}, author = {Bech, PK and Jarmusch, SA and Rasmussen, JA and Limborg, MT and Gram, L and Henriksen, NNSE}, title = {Succession of microbial community composition and secondary metabolism during marine biofilm development.}, journal = {ISME communications}, volume = {4}, number = {1}, pages = {ycae006}, pmid = {38390522}, issn = {2730-6151}, abstract = {In nature, secondary metabolites mediate interactions between microorganisms residing in complex microbial communities. However, the degree to which community dynamics can be linked to secondary metabolite potential remains largely unknown. In this study, we address the relationship between community succession and secondary metabolism variation. We used 16S and 18S rRNA gene and adenylation domain amplicon sequencing, genome-resolved metagenomics, and untargeted metabolomics to track the taxons, biosynthetic gene clusters, and metabolome dynamics in situ of microorganisms during marine biofilm succession over 113 days. Two phases were identified during the community succession, with a clear shift around Day 29, where the alkaloid secondary metabolites, pseudanes, were also detected. The microbial secondary metabolite potential changed between the phases, and only a few community members, including Myxococotta spp., were responsible for the majority of the biosynthetic gene cluster potential in the early succession phase. In the late phase, bryozoans and benthic copepods were detected, and the microbial nonribosomal peptide potential drastically decreased in association with a reduction in the relative abundance of the prolific secondary metabolite producers. Conclusively, this study provides evidence that the early succession of the marine biofilm community favors prokaryotes with high nonribosomal peptide synthetase potential. In contrast, the late succession is dominated by multicellular eukaryotes and a reduction in bacterial nonribosomal peptide synthetase potential.}, } @article {pmid38387884, year = {2024}, author = {Vieira, WO and de-Jesus-Soares, A and Lopes, EM and Gomes, BPFA and Lima, BP}, title = {Effect of supplementary sodium hypochlorite agitation techniques on an ex vivo oral multispecies biofilm during passive disinfection of simulated immature roots.}, journal = {International endodontic journal}, volume = {}, number = {}, pages = {}, doi = {10.1111/iej.14053}, pmid = {38387884}, issn = {1365-2591}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //University of Minnesota, School of Dentistry/ ; }, abstract = {AIM: To compare the effect of different sodium hypochlorite (NaOCl) agitation techniques on an ex vivo oral multispecies biofilm during passive disinfection of simulated immature roots.

METHODOLOGY: Extracted human teeth were prepared to simulate immature roots. They were infected with a dental plaque-derived multispecies biofilm and cultured for 14 days. The roots were randomly designated into four groups: (1) negative control (PBS), (2) 1.5% NaOCl (CNI), (3) CNI + Ultrasonic activation (UA), (4) CNI + EasyClean agitation (ECA), (5) CNI + XP-endo finisher agitation (XPF), and (6) positive control (6% NaOCl). Biofilm samples were collected from the root canals and used to determine the number of viable cells (colony-forming units), scanning electron microscopy, and 16S rRNA gene sequencing. The mean colony-forming units per mL (CFU/mL) were analysed using One-way anova. 16S rRNA sequencing data were analysed for alpha (observed OTUs, Shannon index, and Chao1) and beta diversity (Bray-Curtis dissimilarities). The LEfSe analysis was used to determine the effect of treatment procedures on the abundance of root canal microbiota. The significance was set at .05.

RESULTS: PBS and CNI samples had significantly higher CFU/mL counts than UA, ECA, XPF, and 6% NaOCl samples (p < .05). The pre-treatment, PBS, and CNI groups had significantly greater alpha diversity than the UA, ECA, XPF, and 6% NaOCl groups (p < .05). NaOCl agitation groups and the 6% NaOCl group achieved a more pronounced reduction in bacteria from the genera Fusobacterium, Actinomyces, Porphyromonas, and Capnocytophaga.

CONCLUSIONS: The effectiveness of passive disinfection protocols was enhanced by NaOCl agitation techniques, suggesting that this supplementary method can improve the outcome of revitalization procedures.}, } @article {pmid38387667, year = {2024}, author = {Hong, P and Sun, X and Yuan, S and Wang, Y and Gong, S and Zhang, Y and Sang, P and Xiao, B and Shu, Y}, title = {Nitrogen removal intensification of biofilm through bioaugmentation with Methylobacterium gregans DC-1 during wastewater treatment.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {141467}, doi = {10.1016/j.chemosphere.2024.141467}, pmid = {38387667}, issn = {1879-1298}, abstract = {The increasing concern for environmental remediation has led to a search for effective methods to remove eutrophic nutrients. In this study, Methylobacterium gregans DC-1 was utilized to improve nitrogen removal in a sequencing batch biofilm reactor (SBBR) via aerobic denitrification. This bacterium has the extraordinary characteristics of strong auto-aggregation and a high ability to remove nitrogen efficiently, making it an ideal candidate for enhanced treatment of nitrogen-rich wastewater. This strain was used for the bioassessment of a test reactor (SBBRbio), which showed a shorter biofilm formation time compared to a control reactor (SBBRcon) without this strain inoculation. Moreover, the enhanced biofilm was enriched in TB-EPS and had a wider variety of protein secondary structures than SBBRcon. During the stabilization phase of SBBRbio, the EPS molecules showed the highest proportion of intermolecular hydrogen bonding. It is possible that bioaugmentation with this strain positively affects the structural stability of biofilm. At influent ammonia loadings of 100 and 150 mg. L[-1], the average reduction of ammonia and nitrate-nitrogen was higher in the experimental system compared to the control system. Additionally, nitrite-N accumulation was lower and N2O production decreased compared to the control. Analysis of the microbial community structure demonstrated successful colonization in the bioreactor by a highly nitrogen-tolerant strain that efficiently removed inorganic nitrogen. These results illustrate the great potential of this type of denitrifying bacteria in the application of bioaugmentation systems.}, } @article {pmid38387358, year = {2024}, author = {Cheng, Y and Quan, L and Vadiveloo, A and Yang, L and Saber, AA and Lan, S and A Alsaif, SS and Wang, Z and Wu, L}, title = {Optimizing the algae-bacteria biofilm reactor for imidacloprid wastewater treatment: An evaluation of hydraulic retention times for enhanced efficiency and energy savings.}, journal = {Journal of environmental management}, volume = {354}, number = {}, pages = {120420}, doi = {10.1016/j.jenvman.2024.120420}, pmid = {38387358}, issn = {1095-8630}, abstract = {Recent observations have highlighted the rapidly growing prevalence of emerging contaminants such as Imidacloprid (IMI) within our environment. These insecticidal pollutants, coexisting with more traditional contaminants, have become predominant in aquatic systems, posing risks to both human and ecological well-being. Among the various wastewater treatment approaches tested, biofilm reactors are currently gaining prominence. In this study, we employed an Algae-Bacteria Biofilm Reactor (ABBR) to concurrently address both conventional and emergent contaminants, specifically IMI, over an extended timeframe. Following a 60-day assessment, the ABBR consistently demonstrated removal efficiencies exceeding 85% for total dissolved nitrogen, ammonia nitrogen, and total dissolved phosphorus, and also achieved removal efficacy for the soluble chemical oxygen demand (sCOD). Despite the removal efficiency of IMI (with initial concentration is 1.0 mg/L) in ABBR showed a gradual decline over the extended period, it remained consistently effective over 50% due to the microalgae-mediated free radical reactions, indicating the ABBR's sustained efficiency in long-duration operations. Additionally, applying some non-conventional modifications, like aeration removal and reducing light exposure, demonstrated minimal impact on the reactor's pollutant removal efficiencies, achieving comparable results to the control group (which utilized aeration with a 14:10 light/dark ratio), 0.92 kW h/L/d of electricity can be saved economically, which accentuated the potential for energy conservation. An in-depth analysis of the treated effluents from the ABBRs, using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique, uncovered four potential transformation pathways for IMI. Overall, our findings suggest that these optimized processes did not influence the transformation products of IMI, thereby reaffirming the viability of our proposed optimization.}, } @article {pmid38387268, year = {2024}, author = {Guo, X and Ong, WM and Zhao, HP and Lai, CY}, title = {Enzyme-induced reactive oxygen species trigger oxidative degradation of sulfamethoxazole within a methanotrophic biofilm.}, journal = {Water research}, volume = {253}, number = {}, pages = {121330}, doi = {10.1016/j.watres.2024.121330}, pmid = {38387268}, issn = {1879-2448}, abstract = {Although microorganisms carrying copper-containing membrane-bound monooxygenase (CuMMOs), such as particulate methane monooxygenase (pMMO) and ammonia monooxygenase (AMO), have been extensively documented for their capability to degrade organic micropollutants (OMPs), the underlying reactive mechanism remains elusive. In this study, we for the first time demonstrate biogenic reactive oxygen species (ROS) play important roles in the degradation of sulfamethoxazole (SMX), a representative OMP, within a methane-fed biofilm. Highly-efficient and consistent SMX biodegradation was achieved in a CH4-based membrane biofilm reactor (MBfR), manifesting a remarkable SMX removal rate of 1210.6 ± 39.0 μg·L[-1]·d[-1]. Enzyme inhibition and ROS clearance experiments confirmed the significant contribution of ROS, which were generated through the catalytic reaction of pMMO and AMO enzymes, in facilitating SMX degradation. Through a combination of density functional theory (DFT) calculations, electron paramagnetic resonance (EPR) analysis, and transformation product detection, we elucidated that the ROS primarily targeted the aniline group in the SMX molecule, inducing the formation of aromatic radicals and its progressive mineralization. In contrast, the isoxazole-ring was not susceptible to electrophilic ROS attacks, leading to accumulation of 3-amino-5-methylisoxazole (3A5MI). Furthermore, microbiological analysis suggested Methylosarcina (a methanotroph) and Candidatus Nitrosotenuis (an ammonia-oxidizing archaea) collaborated as the SMX degraders, who carried highly conserved and expressed CuMMOs (pMMO and AMO) for ROS generation, thereby triggering the oxidative degradation of SMX. This study deciphers SMX biodegradation through a fresh perspective of free radical chemistry, and concurrently providing a theoretical framework for the advancement of environmental biotechnologies aimed at OMP removal.}, } @article {pmid38385459, year = {2024}, author = {Mehmood, S and Hussain, M and Bux, K and Hussain, Z and Raza Shah, M and Ali Jakhrani, M and Ali Channar, P and Begum, I and Saboor, R and Yildiz, CB and Ali, K and Herwig, R}, title = {Structural dynamics and anti-biofilm screening of novel imidazole derivative to explore their anti-biofilm inhibition mechanism against Pseudomonas Aeruginosa.}, journal = {Journal of biomolecular structure & dynamics}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/07391102.2024.2317983}, pmid = {38385459}, issn = {1538-0254}, abstract = {The biofilm formation is still prevalent mechanism of developing the drug resistance in the Pseudomonas aeruginosa, gram-negative bacteria, known for its major role in nosocomial, ventilator-associated pneumonia (VAP), lung infections and catheter-associated urinary tract infections. As best of our knowledge, current study first time reports the most potent inhibitors of LasR, a transcriptional activator of biofilm and virulence regulating genes in, Pseudomonas aeruginosa LasR, utilizing newly functionalized imidazoles (5a-d), synthesized via 1,3-dipolar cycloaddition using click approach. The synthesized ligands were characterized through Mass Spectrometry and 1H NMR. The binding potency and mode of biding of ligands. Quantum Mechanical(QM) methods were utilized to investigate the electronic basis, HOMO/LUMO and dipole moment of the geometry of the ligands for their binding potency. Dynamics cross correlation matrix (DCCMs) and protein surface analysis were further utilized to explore the structural dynamics of the protein. Free energy of binding of ligands and protein were further estimated using Molecular Mechanical Energies with the Poisson-Boltzmann surface area (MMPBSA) method. Molecular Docking studies revealed significant negative binding energies (5a - 10.33, 5b -10.09, 5c - 10.11, and 5d -8.33 KJ/mol). HOMO/LUMO and potential energy surface map estimation showed the ligands(5a) with lower energy gaps and larger dipole moments had relatively larger binding potency. The significant change in the structural dynamics of LasR protein due to complex formation with newlyfunctionalized imidazoles ligands. Hydrogen bond surface analysis followed by MMPBSA calculations of free energy of binding further complemented the Molecular docking revelations showing the specifically ligand (5a) having the relatively higher energy of binding(-65.22kj/mol).Communicated by Ramaswamy H. Sarma.}, } @article {pmid38385433, year = {2024}, author = {Jiang, F and Wang, J and Ren, Z and Hu, Y and Wang, B and Li, M and Yu, J and Tang, J and Guo, G and Cheng, Y and Han, P and Shen, H}, title = {Targeted Light-Induced Immunomodulatory Strategy for Implant-Associated Infections via Reversing Biofilm-Mediated Immunosuppression.}, journal = {ACS nano}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsnano.3c10172}, pmid = {38385433}, issn = {1936-086X}, abstract = {The clinical treatment efficacy for implant-associated infections (IAIs), particularly those caused by Methicillin-resistant Staphylococcus aureus (MRSA), remains unsatisfactory, primarily due to the formation of biofilm barriers and the resulting immunosuppressive microenvironment, leading to the chronicity and recurrence of IAIs. To address this challenge, we propose a light-induced immune enhancement strategy, synthesizing BSA@MnO2@Ce6@Van (BMCV). The BMCV exhibits precise targeting and adhesion to the S. aureus biofilm-infected region, coupled with its capacity to catalyze oxygen generation from H2O2 in the hypoxic and acidic biofilm microenvironment (BME), promoting oxygen-dependent photodynamic therapy efficacy while ensuring continuous release of manganese ions. Notably, targeted BMCV can penetrate biofilms, producing ROS that degrade extracellular DNA, disrupting the biofilm structure and impairing its barrier function, making it vulnerable to infiltration and elimination by the immune system. Furthermore, light-induced reactive oxygen species (ROS) around the biofilm can lyse S. aureus, triggering bacterium-like immunogenic cell death (ICD), releasing abundant immune costimulatory factors, facilitating the recognition and maturation of antigen-presenting cells (APCs), and activating adaptive immunity. Additionally, manganese ions in the BME act as immunoadjuvants, further amplifying macrophage-mediated innate and adaptive immune responses and reversing the immunologically cold BME to an immunologically hot BME. We prove that our synthesized BMCV elicits a robust adaptive immune response in vivo, effectively clearing primary IAIs and inducing long-term immune memory to prevent recurrence. Our study introduces a potent light-induced immunomodulatory nanoplatform capable of reversing the biofilm-induced immunosuppressive microenvironment and disrupting biofilm-mediated protective barriers, offering a promising immunotherapeutic strategy for addressing challenging S. aureus IAIs.}, } @article {pmid38384468, year = {2024}, author = {Juszczak, M and Zawrotniak, M and Rapala-Kozik, M}, title = {Complexation of fungal extracellular nucleic acids by host LL-37 peptide shapes neutrophil response to Candida albicans biofilm.}, journal = {Frontiers in immunology}, volume = {15}, number = {}, pages = {1295168}, pmid = {38384468}, issn = {1664-3224}, abstract = {Candida albicans remains the predominant cause of fungal infections, where adhered microbial cells form biofilms - densely packed communities. The central feature of C. albicans biofilms is the production of an extracellular matrix (ECM) consisting of polymers and extracellular nucleic acids (eDNA, eRNA), which significantly impedes the infiltration of host cells. Neutrophils, as crucial players in the innate host defense, employ several mechanisms to eradicate the fungal infection, including NETosis, endocytosis, or the release of granules containing, among others, antimicrobial peptides (AMPs). The main representative of these is the positively charged peptide LL-37 formed from an inactive precursor (hCAP18). In addition to its antimicrobial functions, this peptide possesses a propensity to interact with negatively charged molecules, including nucleic acids. Our in vitro studies have demonstrated that LL-37 contacting with C. albicans nucleic acids, isolated from biofilm, are complexed by the peptide and its shorter derivatives, as confirmed by electrophoretic mobility shift assays. We indicated that the generation of the complexes induces discernible alterations in the neutrophil response to fungal nucleic acids compared to the effects of unconjugated molecules. Our analyses involving fluorescence microscopy, flow cytometry, and Western blotting revealed that stimulation of neutrophils with DNA:LL-37 or RNA:LL-37 complexes hamper the activation of pro-apoptotic caspases 3 and 7 and fosters increased activation of anti-apoptotic pathways mediated by the Mcl-1 protein. Furthermore, the formation of complexes elicits a dual effect on neutrophil immune response. Firstly, they facilitate increased nucleic acid uptake, as evidenced by microscopic observations, and enhance the pro-inflammatory response, promoting IL-8 production. Secondly, the complexes detection suppresses the production of reactive oxygen species and attenuates NETosis activation. In conclusion, these findings may imply that the neutrophil immune response shifts toward mobilizing the immune system as a whole, rather than inactivating the pathogen locally. Our findings shed new light on the intricate interplay between the constituents of the C. albicans biofilm and the host's immune response and indicate possible reasons for the elimination of NETosis from the arsenal of the neutrophil response during contact with the fungal biofilm.}, } @article {pmid38384189, year = {2024}, author = {Whitworth, P and Aldred, N and Finlay, JA and Reynolds, KJ and Plummer, J and Clare, AS}, title = {UV-C LED-induced cyclobutane pyrimidine dimer formation, lesion repair and mutagenesis in the biofilm-forming diatom, Navicula incerta.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2024.2319178}, pmid = {38384189}, issn = {1029-2454}, abstract = {The use of ultraviolet-C (UV-C) irradiation in marine biofouling control is a relatively new and potentially disruptive technology. This study examined effects of UV-C exposure on the biofilm-forming diatom, Navicula incerta. UV-C-induced mutations were identified via Illumina HiSeq. A de novo genome was assembled from control sequences and reads from UV-C-exposed treatments were mapped to this genome, with a quantitative estimate of mutagenesis then derived from the frequency of single nucleotide polymorphisms. UV-C exposure increased cyclobutane pyrimidine dimer (CPD) abundance with a direct correlation between lesion formation and fluency. Cellular repair mechanisms gradually reduced CPDs over time, with the highest UV-C fluence treatments having the fastest repair rates. Mutation abundances were, however, negatively correlated with CPD abundance suggesting that UV-C exposure may influence lesion repair. The threshold fluence for CPD formation exceeding CPD repair was >1.27 J cm[-2]. Fluences >2.54 J cm[-2] were predicted to inhibit repair mechanisms. While UV-C holds considerable promise for marine antifouling, diatoms are just one, albeit an important, component of marine biofouling communities. Determining fluence thresholds for other representative taxa, highlighting the most resistant, would allow UV-C treatments to be specifically tuned to target biofouling organisms, whilst limiting environmental effects and the power requirement.}, } @article {pmid38383718, year = {2024}, author = {Bagińska, N and Grygiel, I and Orwat, F and Harhala, MA and Jędrusiak, A and Gębarowska, E and Letkiewicz, S and Górski, A and Jończyk-Matysiak, E}, title = {Stability study in selected conditions and biofilm-reducing activity of phages active against drug-resistant Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {4285}, pmid = {38383718}, issn = {2045-2322}, support = {NOR/SGS/ACIPHAGE/0192/2020//Small Grant Scheme 2020 Call, the Norwey grants; National Center for Research and Development/ ; }, abstract = {Acinetobacter baumannii is currently a serious threat to human health, especially to people with immunodeficiency as well as patients with prolonged hospital stays and those undergoing invasive medical procedures. The ever-increasing percentage of strains characterized by multidrug resistance to widely used antibiotics and their ability to form biofilms make it difficult to fight infections with traditional antibiotic therapy. In view of the above, phage therapy seems to be extremely attractive. Therefore, phages with good storage stability are recommended for therapeutic purposes. In this work, we present the results of studies on the stability of 12 phages specific for A. baumannii under different conditions (including temperature, different pH values, commercially available disinfectants, essential oils, and surfactants) and in the urine of patients with urinary tract infections (UTIs). Based on our long-term stability studies, the most optimal storage method for the A. baumannii phage turned out to be - 70 °C. In contrast, 60 °C caused a significant decrease in phage activity after 1 h of incubation. The tested phages were the most stable at a pH from 7.0 to 9.0, with the most inactivating pH being strongly acidic. Interestingly, ethanol-based disinfectants caused a significant decrease in phage titers even after 30 s of incubation. Moreover, copper and silver nanoparticle solutions also caused a decrease in phage titers (which was statistically significant, except for the Acba_3 phage incubated in silver solution), but to a much lesser extent than disinfectants. However, bacteriophages incubated for 24 h in essential oils (cinnamon and eucalyptus) can be considered stable.}, } @article {pmid38382601, year = {2024}, author = {Moreno, Y and Moreno-Mesonero, L and Soler, P and Zornoza, A and Soriano, A}, title = {Influence of drinking water biofilm microbiome on water quality: Insights from a real-scale distribution system.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {171086}, doi = {10.1016/j.scitotenv.2024.171086}, pmid = {38382601}, issn = {1879-1026}, abstract = {Biofilms, constituting over 95 % of the biomass in drinking water distribution systems, form an ecosystem impacting both the aesthetic and microbiological quality of water. This study investigates the microbiome of biofilms within a real-scale drinking water distribution system in eastern Spain, utilizing amplicon-based metagenomics. Forty-one biofilm samples underwent processing and sequencing to analyze both bacterial and eukaryotic microbiomes, with an assessment of active biomass. Genus-level analysis revealed considerable heterogeneity, with Desulfovibrio, Ralstonia, Bradyrhizobium, Methylocystis, and Bacillus identified as predominant genera. Notably, bacteria associated with corrosion processes, including Desulfovibrio, Sulfuricella, Hyphomicrobium, and Methylobacterium, were prevalent. Potentially pathogenic bacteria such as Helicobacter, Pseudomonas, and Legionella were also detected. Among protozoa, Opisthokonta and Archaeplastida were the most abundant groups in biofilm samples, with potential pathogenic eukaryotes (Acanthamoeba, Naegleria, Blastocystis) identified. Interestingly, no direct correlation between microbiota composition and pipe materials was observed. The study suggests that the usual concentration of free chlorine in bulk water proved insufficient to prevent the presence of undesirable bacteria and protozoa in biofilms, which exhibited a high concentration of active biomass.}, } @article {pmid38380422, year = {2024}, author = {Saad, MG and Beyenal, H and Dong, WJ}, title = {Dual roles of the conditional extracellular vesicles derived from Pseudomonas aeruginosa biofilms: Promoting and inhibiting bacterial biofilm growth.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100183}, pmid = {38380422}, issn = {2590-2075}, abstract = {Antibiotic-resistant biofilm infections have emerged as public health concerns because of their enhanced tolerance to high-dose antibiotic treatments. The biofilm life cycle involves multiple developmental stages, which are tightly regulated by active cell-cell communication via specific extracellular signal messengers such as extracellular vesicles. This study was aimed at exploring the roles of extracellular vesicles secreted by Pseudomonas aeruginosa at different developmental stages in controlling biofilm growth. Our results show that extracellular vesicles secreted by P. aeruginosa biofilms during their exponential growth phase (G-EVs) enhance biofilm growth. In contrast, extracellular vesicles secreted by P. aeruginosa biofilms during their death/survival phase (D-EVs) can effectively inhibit/eliminate P. aeruginosa PAO1 biofilms up to 4.8-log10 CFU/cm[2]. The inhibition effectiveness of D-EVs against P. aeruginosa biofilms grown for 96 h improved further in the presence of 10-50 μM Fe[3+] ions. Proteomic analysis suggests the inhibition involves an iron-dependent ferroptosis mechanism. This study is the first to report the functional role of bacterial extracellular vesicles in bacterial growth, which depends on the developmental stage of the parent bacteria. The finding of D-EV-activated ferroptosis-based bacterial death may have significant implications for preventing antibiotic resistance in biofilms.}, } @article {pmid38379770, year = {2024}, author = {Xie, H and Zhang, R and Guo, R and Zhang, Y and Zhang, J and Li, H and Fu, Q and Wang, X}, title = {Characterization of AI-2/LuxS quorum sensing system in biofilm formation, pathogenesis of Streptococcus equi subsp. zooepidemicus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {14}, number = {}, pages = {1339131}, pmid = {38379770}, issn = {2235-2988}, abstract = {Streptococcus equi subsp. zooepidemicus (SEZ) is an opportunistic pathogen of both humans and animals. Quorum sensing (QS) plays an important role in the regulation of bacterial group behaviors. The aim of this study was to characterize the LuxS in SEZ and evaluate its impact on biofilm formation, pathogenesis and gene expression. The wild-type SEZ and its LuxS mutant (ΔluxS) were examined for growth, biofilm formation, virulence factors, and transcriptomic profiles. Our results showed that LuxS deficiency did not affect SEZ hemolytic activity, adhesion or capsule production. For biofilm assay demonstrated that mutation in the luxS gene significantly enhances biofilm formation, produced a denser biofilm and attached to a glass surface. RAW264.7 cell infection indicated that ΔluxS promoted macrophage apoptosis and pro-inflammatory responses. In mice infection, there was no significant difference in mortality between SEZ and ΔluxS. However, the bacterial load in the spleen of mice infected with ΔluxS was significantly higher than in those infected with SEZ. And the pathological analysis further indicated that spleen damage was more severe in the ΔluxS group. Moreover, transcriptomics analysis revealed significant alterations in carbon metabolism, RNA binding and stress response genes in ΔluxS. In summary, this study provides the first evidence of AI-2/LuxS QS system in SEZ and reveals its regulatory effects on biofilm formation, pathogenicity and gene expression.}, } @article {pmid38379455, year = {2024}, author = {Short, B and Delaney, C and Johnston, W and Litherland, GJ and Lockhart, JC and Williams, C and Mackay, WG and Ramage, G}, title = {Informed development of a multi-species biofilm in chronic obstructive pulmonary disease.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13386}, pmid = {38379455}, issn = {1600-0463}, support = {INT-VA/045//Interreg/ ; }, abstract = {Recent evidence indicates that microbial biofilm aggregates inhabit the lungs of COPD patients and actively contribute towards chronic colonization and repeat infections. However, there are no contextually relevant complex biofilm models for COPD research. In this study, a meta-analysis of the lung microbiome in COPD was used to inform development of an optimized biofilm model composed of genera highly associated with COPD. Bioinformatic analysis showed that although diversity matrices of COPD microbiomes were similar to healthy controls, and internal compositions made it possible to accurately differentiate between these cohorts (AUC = 0.939). Genera that best defined these patients included Haemophilus, Moraxella and Streptococcus. Many studies fail to account for fungi; therefore, Candida albicans was included in the creation of an interkingdom biofilm model. These organisms formed a biofilm capable of tolerating high concentrations of antimicrobial therapies with no significant reductions in viability. However, combined therapies of antibiotics and an antifungal resulted in significant reductions in viable cells throughout the biofilm (p < 0.05). This biofilm model is representative of the COPD lung microbiome and results from in vitro antimicrobial challenge experiments indicate that targeting both bacteria and fungi in these interkingdom communities will be required for more positive clinical outcomes.}, } @article {pmid38377929, year = {2024}, author = {Zheng, S and Lin, T and Chen, H and Zhang, X and Jiang, F}, title = {Impact of changes in biofilm composition response following chlorine and chloramine disinfection on nitrogenous disinfection byproduct formation and toxicity risk in drinking water distribution systems.}, journal = {Water research}, volume = {253}, number = {}, pages = {121331}, doi = {10.1016/j.watres.2024.121331}, pmid = {38377929}, issn = {1879-2448}, abstract = {In practical drinking water treatment, chlorine and chloramine disinfection exhibit different mechanisms that affect biofilm growth. This study focused on the influence of biofilm composition changes, especially extracellular polymeric substance (EPS) fractions, on the potential formation and toxicity of nitrogenous disinfection by-products (N-DBP). Significant differences in microbial diversity and community structure were observed between the chlorine and chloramine treatments. Notably, the biofilms from the chloramine-treated group had higher microbial dominance and greater accumulation of organic precursors, as evidenced by the semi-quantitative confocal laser-scanning microscopy assay of more concentrated microbial aggregates and polysaccharide proteins in the samples. Additionally, the chloramine-treated group compared with chlorine had a higher EPS matrix content, with a 13.5 % increase in protein. Furthermore, the protein distribution within the biofilm differed; in the chlorine group, proteins were concentrated in the central region, whereas in the chloramine group, proteins were primarily located at the water-biofilm interface. Notably, functional prediction analyses of protein fractions in biofilms revealed specific functional regulation patterns and increased metabolism-related abundance of proteins in the chlorine-treated group. This increase was particularly pronounced for proteins such as dehydrogenases, reductases, transcription factors, and acyl-CoA dehydrogenases. By combining the Fukui function and density functional calculations to further analyse the effect of biofilm component changes on N-DBP production under chlorine/chloramine and by assessing the toxicity risk potential of N-DBP, it was determined that chloramine disinfection is detrimental to biofilm control and the accumulation of protein precursors has a higher formation potential of N-DBPs and toxicity risk, increasing the health risk of drinking water.}, } @article {pmid38376204, year = {2024}, author = {Sangha, JS and Barrett, P and Curtis, TP and Métris, A and Jakubovics, NS and Ofiteru, ID}, title = {Effects of glucose and lactate on Streptococcus mutans abundance in a novel multispecies oral biofilm model.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0371323}, doi = {10.1128/spectrum.03713-23}, pmid = {38376204}, issn = {2165-0497}, abstract = {The oral microbiome plays an important role in protecting oral health. Here, we established a controlled mixed-species in vitro biofilm model and used it to assess the impact of glucose and lactate on the ability of Streptococcus mutans, an acidogenic and aciduric species, to compete with commensal oral bacteria. A chemically defined medium was developed that supported the growth of S. mutans and four common early colonizers of dental plaque: Streptococcus gordonii, Actinomyces oris, Neisseria subflava, and Veillonella parvula. Biofilms containing the early colonizers were developed in a continuous flow bioreactor, exposed to S. mutans, and incubated for up to 7 days. The abundance of bacteria was estimated by quantitative polymerase chain reaction (qPCR). At high glucose and high lactate, the pH in bulk fluid rapidly decreased to approximately 5.2, and S. mutans outgrew other species in biofilms. In low glucose and high lactate, the pH remained above 5.5, and V. parvula was the most abundant species in biofilms. By contrast, in low glucose and low lactate, the pH remained above 6.0 throughout the experiment, and the microbial community in biofilms was relatively balanced. Fluorescence in situ hybridization confirmed that all species were present in the biofilm and the majority of cells were viable using live/dead staining. These data demonstrate that carbon source concentration is critical for microbial homeostasis in model oral biofilms. Furthermore, we established an experimental system that can support the development of computational models to predict transitions to microbial dysbiosis based on metabolic interactions.IMPORTANCEWe developed a controlled (by removing host factor) dynamic system metabolically representative of early colonization of Streptococcus mutans not measurable in vivo. Hypotheses on factors influencing S. mutans colonization, such as community composition and inoculation sequence and the effect of metabolite concentrations, can be tested and used to predict the effect of interventions such as dietary modifications or the use of toothpaste or mouthwash on S. mutans colonization. The defined in vitro model (species and medium) can be simulated in an in silico model to explore more of the parameter space.}, } @article {pmid38375536, year = {2024}, author = {Braun, J and Ortega-Liebana, MC and Unciti-Broceta, A and Sieber, SA}, title = {A Pd-labile fluoroquinolone prodrug efficiently prevents biofilm formation on coated surfaces.}, journal = {Organic & biomolecular chemistry}, volume = {}, number = {}, pages = {}, doi = {10.1039/d4ob00014e}, pmid = {38375536}, issn = {1477-0539}, abstract = {Surface-adhered bacteria on implants represent a major challenge for antibiotic treatment. We introduce hydrogel-coated surfaces loaded with tailored Pd-nanosheets which catalyze the release of antibiotics from inactive prodrugs. Masked and antibiotically inactive fluoroquinolone analogs were efficiently activated at the surface and prevented the formation of Staphylococcus aureus biofilms.}, } @article {pmid38374488, year = {2024}, author = {Kim, KH and Lévesque, C and Malkhassian, G and Basrani, B}, title = {Efficacy of the GentleWave System in the removal of biofilm from the mesial roots of mandibular molars before and after minimal instrumentation: An ex vivo study.}, journal = {International endodontic journal}, volume = {}, number = {}, pages = {}, doi = {10.1111/iej.14044}, pmid = {38374488}, issn = {1365-2591}, support = {//Canadian Academy of Endodontics Endowment Fund/ ; //International Federation of Endodontic Association/ ; //American Association of Endodontists Foundation/ ; //Alpha Omega Foundation/ ; //Sonendo Inc/ ; //Endotech Inc/ ; }, abstract = {AIM: To compare the efficacy of Enterococcus faecalis biofilm removal using the GentleWave System (GWS) (Sonendo Inc, CA) on non-instrumented versus minimally instrumented root canal systems.

METHODOLOGY: Thirty-four mandibular molars were autoclaved and allocated to four groups: Negative control (n = 5); positive control (n = 5); Group 1: non-instrumentation + GWS (NI + GWS) (n = 12); and Group 2: minimal instrumentation + GWS (MI + GWS) (n = 12). Of 34 samples, 24 samples with Vertucci type 2 configuration within the mesial root of each sample were allocated to Groups 1 and 2 and then matched based on the working length and root canal configuration. After inoculation of samples with E. faecalis for 3 weeks, the GWS was used on Group 1 without any instrumentation and Group 2 after instrumentation of mesial canals until size 20/06v. CFU and SEM analysis were used.

RESULTS: Log10 (CFU/mL) from the positive control, and Group 1 and 2 were 7.41 ± 0.53, 3.41 ± 1.54, and 3.21 ± 1.54, respectively. Both groups showed a statistically significant difference in the reduction of viable E. faecalis cells compared to the positive control (Group 1 [p = .0001] and Group 2 [p < .0001]), whilst showing no significant difference between the two tested groups (p < .05).

CONCLUSION: The use of GWS on the non-instrumented root canal system could be an effective disinfection protocol in removing the biofilm without dentin debris formation.}, } @article {pmid38373897, year = {2024}, author = {Jiang, H and Wang, Z and Jia, AQ}, title = {Methyl gallate from Camellia nitidissima Chi flowers reduces quorum sensing related virulence and biofilm formation against Aeromonas hydrophila.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2024.2316611}, pmid = {38373897}, issn = {1029-2454}, abstract = {Aeromonas hydrophila, a Gram-negative zoonotic bacterium, causes high mortality in fish farming and immunocompromised patients. This study aimed to extract methyl gallate (MG) from the flowers of Camellia nitidissima Chi and evaluate its potential as a quorum sensing inhibitor (QSI) against Aeromonas hydrophila SHAe 115. MG reduced QS-associated virulence factors, including hemolysis, protease, and lipase, while impairing swimming motility and biofilm formation. Additionally, MG down-regulated positive regulatory genes (ahyR, fleQ) and up-regulated negative regulators (litR, fleN). This highlights MG's promise as a potent QSI for A. hydrophila SHAe 115, advancing strategies against infections in aquaculture and human health.}, } @article {pmid38371939, year = {2024}, author = {Barone, S and Mateu, B and Turco, L and Pelliccia, S and Lembo, F and Summa, V and Buommino, E and Brindisi, M}, title = {Unveiling the modulation of Pseudomonas aeruginosa virulence and biofilm formation by selective histone deacetylase 6 inhibitors.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1340585}, pmid = {38371939}, issn = {1664-302X}, abstract = {Bacterial infections represent a key public health issue due to the occurrence of multidrug-resistant bacteria. Recently, the amount of data supporting the dynamic control of epigenetic pathways by environmental cues has triggered research efforts toward the clarification of their role in microbial infections. Among protein post-translational modifications, reversible acetylation is the most implicated in the feedback to environmental stimuli and in cellular homeostasis. Accordingly, the latest studies identified the histone deacetylase 6 (HDAC6) enzyme as a crucial player in the complex molecular machinery underlying bacterial clearance or killing. A very important milestone for the elucidation of the consequence of HDAC6 activity in bacterial infections is herein described, unveiling for the first time the role of a potent HDAC6 inhibitor in interfering with biofilm formation and modulating virulence factors of P. aeruginosa. We demonstrated that compound F2F-2020202 affected the production of some important virulence factors in P. aeruginosa, namely pyocyanin and rhamnolipids, clearly impairing its ability to form biofilm. Furthermore, evidence of possible QS involvement is supported by differential regulation of specific genes, namely RhlI, phAz1, and qsrO. The data herein obtained also complement and in part explain our previous results with selective HDAC6 inhibitors able to reduce inflammation and bacterial load in chronic infection models recapitulating the cystic fibrosis (CF) phenotype. This study fosters future in-depth investigation to allow the complete elucidation of the molecular mechanisms underlying HDAC6's role in bacterial infections.}, } @article {pmid38371116, year = {2024}, author = {Zubair, M}, title = {Antimicrobial and Anti-Biofilm Activities of Coffea arabica L. Against the Clinical Strains Isolated From Diabetic Foot Ulcers.}, journal = {Cureus}, volume = {16}, number = {1}, pages = {e52539}, pmid = {38371116}, issn = {2168-8184}, abstract = {Diabetes-related complications such as diabetic foot infections foster resilient biofilms, complicating treatment. Innovative therapeutic solutions are urgently needed to address this challenge. In this research, coffee bean powder (green coffee been powder [GCBP], roasted coffee bean powder [RCBP], and spent coffee powder ground [SCPG]) was extracted and assessed for its ability to impede biofilm formation and associated functions in extended-spectrum beta-lactamase (ESBL) and methicillin-resistant Staphylococcus aureus (MRSA)-positive biofilm-forming strains of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) obtained from foot ulcers. GCBP exhibited notable effectiveness in reducing biofilm formation, ranging from 17-76% in monocultures and 17-66% in mixed cultures. It significantly disrupted motility in P. aeruginosa and E. coli, a crucial factor influencing biofilm establishment. The critical biofilm-related functions for attachment and maintenance such as cell surface hydrophobicity and exopolysaccharide production were significantly inhibited at sub-MICs. Notably, GCBP elicited statistically significant reductions (29-59% in monocultures and 28-45% in mixed cultures) in pre-formed biofilms. The reduction in bacterial chitinase activity upon exposure to GCBP implies a potential mechanism for its ability to inhibit biofilm formation. This study emphasizes the potential of green coffee bean extract in tackling antibiotic-resistant bacterial biofilms associated with diabetic foot ulcers, suggesting innovative strategies for infection management through mechanistic understanding and optimized applications.}, } @article {pmid38370578, year = {2023}, author = {Jalalifar, S and Razavi, S and Mirzaei, R and Irajian, G and Pooshang Bagheri, K}, title = {A hope for ineffective antibiotics to return to treatment: investigating the anti-biofilm potential of melittin alone and in combination with penicillin and oxacillin against multidrug resistant-MRSA and -VRSA.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1269392}, pmid = {38370578}, issn = {1664-302X}, abstract = {BACKGROUND: The emergence and rapid spread of multi-drug resistant (MDR) bacterial strains, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA), have posed a significant challenge to the medical community due to their ability to form biofilm and develop resistance to common antibiotics. Traditional antibiotics that were once effective in treating bacterial infections are now becoming increasingly ineffective, leading to severe consequences for patient outcomes. This concerning situation has called for urgent research to explore alternative treatment strategies. Recent studies have shown that antimicrobial peptides (AMPs) hold promise as effective agents against biofilm-associated drug-resistant infections as well as to enhance the efficacy of conventional antibiotics. Accordingly, we aimed to investigate the antimicrobial and antibiofilm effects of melittin AMP, both alone and in combination with penicillin and oxacillin, against biofilm-forming MDR-MRSA and -VRSA.

METHODS: In this study, we investigated the kinetics of biofilm formation and assessed various parameters related to the antimicrobial and antibiofilm efficacy of melittin and antibiotics, both alone and in combination, against MDR-MRSA and -VRSA. The antimicrobial parameters included the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Fractional Inhibitory Concentration Index (FICi), Fractional Bactericidal Concentration Index (FBCi), and the antibiofilm activity of melittin and antibiotics indicated by the Minimum Biofilm Inhibitory Concentration (MBIC), Minimal Biofilm Eradication Concentration (MBEC), Fractional Biofilm Inhibitory Concentration Index (FBICi), and Fractional Biofilm Eradication Concentration Index (FBECi).

RESULTS: The MIC results showed that all S. aureus isolates were resistant to penicillin (≥0.25 μg/mL), and 66% of isolates were resistant to oxacillin. The geometric means of the MIC values for penicillin, oxacillin, and melittin were 19.02, 16, and 1.62 μg/ml, respectively, and the geometric means of the MBC values for penicillin, oxacillin, and melittin were 107.63, 49.35, and 5.45 μg/ml, respectively. The study revealed that the combination indexes of melittin-penicillin and melittin-oxacillin, as determined by FIC values against all isolates, were 0.37 and 0.03, respectively. Additionally, melittin-penicillin and melittin-oxacillin exhibited combination indexes based on FBC values against all isolates at 1.145 and 0.711, respectively. Besides, melittin inhibited the biofilm formation of all S. aureus isolates, with MBIC values ranging from 10 to 1.25 μg/mL, and MBEC values ranging from 40 to 10 μg/mL. Generally, the combination indexes of melittin-penicillin and melittin-oxacillin, determined using FBIC values against all isolates, were 0.23 and 0.177, respectively. Moreover, melittin-penicillin and melittin-oxacillin typically had combination indexes based on FBEC values against all isolates at 5 and 2.97, respectively.

CONCLUSION: In conclusion, our study provides evidence that melittin is effective against both planktonik and biofilm forms of MRSA and VRSA and exhibits significant synergistic effects when combined with antibiotics. These results suggest that melittin and antibiotics could be a potential candidate for further investigation for in vivo infections caused by MDR S. aureus. Furthermore, melittin has the potential to restore the efficacy of penicillin and oxacillin antibiotics in the treatment of MDR infections. Applying AMPs, like melittin, to revive beta-lactam antibiotics against MRSA and VRSA is an innovative approach against antibiotic-resistant bacteria. Further research is needed to optimize dosage and understand melittin mechanism and interactions with beta-lactam antibiotics for successful clinical applications.}, } @article {pmid38370152, year = {2024}, author = {Ravishankar, S and Baldelli, V and Angeletti, C and Raffaelli, N and Landini, P and Rossi, E}, title = {Fluoropyrimidines affect de novo pyrimidine synthesis impairing biofilm formation in Escherichia coli.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100180}, pmid = {38370152}, issn = {2590-2075}, abstract = {Antivirulence agents are considered a promising strategy to treat bacterial infections. Fluoropyrimidines possess antivirulence and antibiofilm activity against Gram-negative bacteria; however, their mechanism of action is yet unknown. Consistent with their known antibiofilm activity, fluoropyrimidines, particularly 5-fluorocytosine (5-FC), impair curli-dependent surface adhesion by Escherichia coli MG1655 via downregulation of curli fimbriae gene transcription. Curli inhibition requires fluoropyrimidine conversion into fluoronucleotides and is not mediated by c-di-GMP or the ymg-rcs envelope stress response axis, previously suggested as the target of fluorouracil antibiofilm activity in E. coli. In contrast, 5-FC hampered the transcription of curli activators RpoS and stimulated the expression of Fis, a curli repressor affected by nucleotide availability. This last observation suggested a possible perturbation of the de novo pyrimidine biosynthesis by 5-FC: indeed, exposure to 5-FC resulted in a ca. 2-fold reduction of UMP intracellular levels while not affecting ATP. Consistently, expression of the de novo pyrimidine biosynthesis genes carB and pyrB was upregulated in the presence of 5-FC. Our results suggest that the antibiofilm activity of fluoropyrimidines is mediated, at least in part, by perturbation of the pyrimidine nucleotide pool. We screened a genome library in search of additional determinants able to counteract the effects of 5-FC. We found that a DNA fragment encoding the unknown protein D8B36_18,480 and the N-terminal domain of the penicillin-binding protein 1b (PBP1b), involved in peptidoglycan synthesis, could restore curli production in the presence of 5-FC. Deletion of the PBP1b-encoding gene mrcB, induced csgBAC transcription, while overexpression of the gene encoding the D8B36_18,480 protein obliterated its expression, possibly as part of a coordinated response in curli regulation with PBP1b. While the two proteins do not appear to be direct targets of 5-FC, their involvement in curli regulation suggests a connection between peptidoglycan biosynthesis and curli production, which might become even more relevant upon pyrimidine starvation and reduced availability of UDP-sugars needed in cell wall biosynthesis. Overall, our findings link the antibiofilm activity of fluoropyrimidines to the redirection of at least two global regulators (RpoS, Fis) by induction of pyrimidine starvation. This highlights the importance of the de novo pyrimidines biosynthesis pathway in controlling virulence mechanisms in different bacteria and makes the pathway a potential target for antivirulence strategies.}, } @article {pmid38369560, year = {2024}, author = {Choi, SS and Lee, JH and Kong, H and Park, EJ}, title = {Biofilm removal effect of diatom complex on 3D printed denture base resin.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {4034}, pmid = {38369560}, issn = {2045-2322}, support = {2004719//Division of Materials Research/ ; 202202962//Ministry of Oceans and Fisheries/ ; 2022R1F1A1063382//Ministry of Science and ICT, South Korea/ ; }, abstract = {For patients who have difficulty in mechanical cleaning of dental appliances, a denture cleaner that can remove biofilm with dense extracellular polymeric substances is needed. The purpose of this study is to evaluate the efficacy of diatom complex with active micro-locomotion for removing biofilms from 3D printed dentures. The diatom complex, which is made by doping MnO2 nanosheets on diatom biosilica, is mixed with H2O2 to generate fine air bubbles continuously. Denture base resin specimens were 3D printed in a roof shape, and Pseudomonas aeruginosa (10[7] CFU/mL) was cultured on those for biofilm formation. Cleaning solutions of phosphate-buffered saline (negative control, NC), 3% H2O2 with peracetic acid (positive control, PC), denture cleanser tablet (DCT), 3% H2O2 with 2 mg/mL diatom complex M (Melosira, DM), 3% H2O2 with 2 mg/mL diatom complex A (Aulacoseira, DA), and DCT with 2 mg/mL DM were prepared and applied. To assess the efficacy of biofilm removal quantitatively, absorbance after cleaning was measured. To evaluate the stability of long-term use, surface roughness, ΔE, surface micro-hardness, and flexural strength of the 3D printed dentures were measured before and after cleaning. Cytotoxicity was evaluated using Cell Counting Kit-8. All statistical analyses were conducted using SPSS for Windows with one-way ANOVA, followed by Scheffe's test as a post hoc (p < 0.05). The group treated with 3% H2O2 with DA demonstrated the lowest absorbance value, followed by the groups treated with 3% H2O2 with DM, PC, DCT, DCT + DM, and finally NC. As a result of Scheffe's test to evaluate the significance of difference between the mean values of each group, statistically significant differences were shown in all groups based on the NC group. The DA and DM groups showed the largest mean difference though there was no significant difference between the two groups. Regarding the evaluation of physical and mechanical properties of the denture base resin, no statistically significant differences were observed before and after cleaning. In the cytotoxicity test, the relative cell count was over 70%, reflecting an absence of cytotoxicity. The diatom complex utilizing active micro-locomotion has effective biofilm removal ability and has a minimal effect in physical and mechanical properties of the substrate with no cytotoxicity.}, } @article {pmid38369083, year = {2024}, author = {Sohn, W and Jiang, J and Su, Z and Zheng, M and Wang, Q and Phuntsho, S and Kyong Shon, H}, title = {Microbial community analysis of membrane bioreactor incorporated with biofilm carriers and activated carbon for nitrification of urine.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130462}, doi = {10.1016/j.biortech.2024.130462}, pmid = {38369083}, issn = {1873-2976}, abstract = {The integration of powdered activated carbon and biofilm carriers in a membrane bioreactor (MBR) presents a promising approach to address the challenge of long hydraulic retention time (HRT) for nitrification of hydrolysed urine. This study investigated the effect of the incorporation in the MBR on microbial dynamics, focusing on dominant nitrifying bacteria. The results showed that significant shifts in microbial compositions were observed with the feed transition to full-strength urine and across different sludge growth forms. Remarkably, the nitrite-oxidizing bacteria Nitrospira were highly enriched in the suspended sludge. Simultaneously, ammonia-oxidizing bacteria, Nitrosococcaceae thrived in the attached biomass, showing a significant seven-fold increase in relative abundance compared to its suspended counterpart. Consequently, the incorporated MBR displayed 36% higher nitrification rate and 40% HRT reduction compared to the conventional MBR. This study provides valuable insights on the potential development of household or building scale on-site nutrient recovery from urine to fertiliser.}, } @article {pmid38368100, year = {2024}, author = {Padaga, SG and Ch, S and Paul, M and Wable, BD and Ghosh, B and Biswas, S}, title = {Chitosan oligosaccharide/pluronic F127 micelles exhibiting anti-biofilm effect to treat bacterial keratitis.}, journal = {Carbohydrate polymers}, volume = {330}, number = {}, pages = {121818}, doi = {10.1016/j.carbpol.2024.121818}, pmid = {38368100}, issn = {1879-1344}, mesh = {Mice ; Animals ; Micelles ; Poloxamer ; *Chitosan/pharmacology ; Staphylococcus aureus ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Lactic Acid/pharmacology ; *Keratitis/drug therapy ; Pseudomonas aeruginosa ; *Lactates ; }, abstract = {Mono or dual chitosan oligosaccharide lactate (COL)-conjugated pluronic F127 polymers, FCOL1 and FCOL2 were prepared, self-assembled to form micelles, and loaded with gatifloxacin. The Gati@FCOL1/Gati@FCOL2 micelles preparation process was optimized by QbD analysis. Micelles were characterized thoroughly for size, CMC, drug compatibility, and viscosity by GPC, DLS, SEM, IR, DSC, and XRD. The micelles exhibited good cellular uptake in both monolayers and spheroids of HCEC. The antibacterial and anti-biofilm activities of the micelles were evaluated on P. aeruginosa and S. aureus. The anti-quorum sensing activity was explored in P. aeruginosa by analyzing micelles' ability to produce virulence factors, including AHLs, pyocyanin, and the motility behavior of the organism. Gati@FCOL2 Ms was mucoadhesive, cornea-penetrant, antibacterial, and inhibited the biofilm formation by P. aeruginosa and S. aureus significantly more than Gati@FCOL1. A significant reduction in bacterial load in mice cornea was observed after Gati@FCOL2 Ms-treatment to the P. aeruginosa-induced bacterial keratitis-infected mice.}, } @article {pmid38366933, year = {2024}, author = {Robertson, SN and Romero, M and Fenn, S and Riedi, PLK and Cámara, M}, title = {Development, characterisation and evaluation of a simple polymicrobial colony biofilm model for testing of antimicrobial wound dressings.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxae042}, pmid = {38366933}, issn = {1365-2672}, abstract = {AIMS: Simple biofilm models are the first step to testing of any antimicrobial and wound dressing, therefore the aim of this study was to develop and validate a simple polymicrobial colony biofilm wound model comprised of Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans on RPMI-1640 agar. The model was then used to evaluate the topical disinfectant chlorohexidine and four commercially available wound dressings using the polymicrobial model. The model used was as a starting point to mimic debridement in clinical care of wounds and the effectiveness of wound dressings evaluated afterwards.

METHODS & RESULTS: Planktonic assessment using AATCC100-2004 demonstrated that all antimicrobial wound dressings reduced the planktonic microbial burden below the limit of detection, however, when challenged with polymicrobial colony biofilms, silver wound dressings showed limited effectiveness (1-2 Log CFU reductions). In contrast a single iodine releasing wound dressing showed potent antibiofilm activity reducing all species CFUs below the limit of detection (>6 log-10 log) depending on the species. A disrupted biofilm model challenge was performed to represent the debridement of a wound and wound silver based wound dressings were found to be marginally more effective than in whole colony biofilm challenges while the iodine containing wound dressing reduced microbial recovery below the limit of detection.

CONCLUSIONS: In this model silver dressings were ineffective versus the whole colony biofilms but showed some recovery of activity versus the disrupted colony biofilm. The iodine wound dressing reduced the viability of all species below the level of detection. This suggests that mode of action of wound dressing should be considered for the type of biofilm challenge as should the clinical use e.g. debridement.}, } @article {pmid38366392, year = {2024}, author = {Lorentzen, ØM and Haukefer, ASB and Johnsen, PJ and Frøhlich, C}, title = {The Biofilm Lifestyle Shapes the Evolution of β-Lactamases.}, journal = {Genome biology and evolution}, volume = {}, number = {}, pages = {}, doi = {10.1093/gbe/evae030}, pmid = {38366392}, issn = {1759-6653}, abstract = {The evolutionary relationship between the biofilm lifestyle and antibiotic resistance enzymes remains a subject of limited understanding. Here, we investigate how β-lactamases affect biofilm formation in Vibrio cholerae and how selection for a biofilm lifestyle impacts the evolution of these enzymes. Genetically diverse β-lactamases expressed in V. cholerae displayed a strong inhibitory effect on biofilm production. To understand how natural evolution affects this antagonistic pleiotropy, we randomly mutagenized one β-lactamase and selected for elevated biofilm formation. Our results revealed that biofilm evolution selects for β-lactamase variants able to hydrolyse β-lactams but without inhibiting biofilms. Mutational analysis of evolved variants demonstrated that restoration of biofilm development was achieved either independent of enzymatic function or by actively leveraging enzymatic activity. Taken together, the biofilm lifestyle can impose a profound selective pressure on antimicrobial resistance enzymes. Shedding light on such evolutionary interplays is of great importance to understand the factors driving antimicrobial resistance.}, } @article {pmid38366298, year = {2024}, author = {Tang, Y and Xiao, N and Zou, J and Mei, Y and Yuan, Y and Wang, M and Wang, Z and Zhou, Y and Chen, Y and Li, S}, title = {Antibiotic resistance, biofilm formation, and molecular epidemiology of Staphylococcus aureus in a tertiary hospital in Xiangyang, China.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {38366298}, issn = {1678-4405}, support = {2021ZD23//Xiangyang Science and Technology Research and Development Project/ ; }, abstract = {Staphylococcus aureus is a common clinical pathogen that causes various human infections. The aim of this study was to investigate the antibiotic susceptibility pattern, molecular epidemiological characteristics, and biofilm formation ability of S. aureus isolates from clinical specimens in Xiangyang and to analyze the correlation among them. A total of 111 non-duplicate S. aureus isolates were collected from the Affiliated Hospital of Hubei University of Arts and Science. All isolates were tested for antibacterial susceptibility. Methicillin-resistant S. aureus (MRSA) was identified by the mecA gene PCR amplification. All isolates were analyzed to determine their biofilm-forming ability using the microplate method. The biofilm-related gene was determined using PCR. SCCmec, MLST, and spa types of MRSA strains were performed to ascertain the molecular characteristics. Among the 111 S. aureus isolates, 45 (40.5%) and 66 (59.5%) were MRSA and MSSA, respectively. The resistance of MRSA strains to the tested antibiotics was significantly stronger than that of MSSA strains. All isolates were able to produce biofilm with levels ranging from strong (28.9%, 18.2%), moderate (62.2%, 62.1%), to weak (8.9%, 19.7%). Strong biofilm formation was observed in MRSA strains than in MSSA strains, based on percentages. There were dynamic changes in molecular epidemic characteristics of MRSA isolates in Xiangyang. SCCmecIVa-ST22-t309, SCCmecIVa-ST59-t437, and SCCmecIVa-ST5-t2460 were currently the main epidemic clones in this region. SCCmecIVa-ST5-t2460 and SCCmecIVa/III-ST22-t309 have stronger antibiotic resistance than SCCmecIVa-ST59-t437 strains, with resistance to 6 ~ 8 detected non-β-lactam antibiotics. The molecular epidemic and resistance attributes of S. aureus should be timely monitored, and effective measures should be adopted to control the clinical infection and spread of the bacteria.}, } @article {pmid38365935, year = {2024}, author = {Yang, N and Røder, HL and Wicaksono, WA and Wassermann, B and Russel, J and Li, X and Nesme, J and Berg, G and Sørensen, SJ and Burmølle, M}, title = {Interspecific interactions facilitate keystone species in a multispecies biofilm that promotes plant growth.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1093/ismejo/wrae012}, pmid = {38365935}, issn = {1751-7370}, abstract = {Microorganisms colonizing plant roots co-exist in complex, spatially structured multispecies biofilm communities. However, little is known about microbial interactions and the underlying spatial organization within biofilm communities established on plant roots. Here, a well-established four-species biofilm model (Stenotrophomonas rhizophila, Paenibacillus amylolyticus, Microbacterium oxydans and Xanthomonas retroflexus, termed as SPMX) was applied to Arabidopsis roots to study the impact of multispecies biofilm on plant growth and the community spatial dynamics on the roots. SPMX co-culture notably promoted root development and plant biomass. Co-cultured SPMX increased root colonization and formed multispecies biofilms, structurally different from those formed by monocultures. By combining 16S rRNA gene amplicon sequencing and fluorescence in situ hybridization with confocal laser scanning microscopy (FISH-CLSM), we found that the composition and spatial organization of the four-species biofilm significantly changed over time. Monoculture P. amylolyticus colonized plant roots poorly, but its population and root colonization were highly enhanced when residing in the four-species biofilm. Exclusion of P. amylolyticus from the community reduced overall biofilm production and root colonization of the three species, resulting in the loss of the plant growth-promoting effects. Combined with spatial analysis, this led to identification of P. amylolyticus as a keystone species. Our findings highlight that weak root colonizers may benefit from mutualistic interactions in complex communities and hereby become important keystone species impacting community spatial organization and function. This work expands the knowledge on spatial organization uncovering interspecific interactions in multispecies biofilm communities on plant roots, beneficial for harnessing microbial mutualism promoting plant growth.}, } @article {pmid38364289, year = {2024}, author = {Pandey, P and Pradhan, S and Meher, K and Lopus, M and Vavilala, SL}, title = {Exploring the efficacy of tryptone-stabilized silver nanoparticles against respiratory tract infection-causing bacteria: a study on planktonic and biofilm forms.}, journal = {Biomedical materials (Bristol, England)}, volume = {}, number = {}, pages = {}, doi = {10.1088/1748-605X/ad2a40}, pmid = {38364289}, issn = {1748-605X}, abstract = {Respiratory tract infections are a common cause of mortality and morbidity in the human population. The overuse of antibiotics to overcome such infections has led to antibiotic resistance. The emergence of Multidrug resistant (MDR) bacteria is necessitating the development of novel therapeutic techniques in order to avoid a major global clinical threat. Our study aims to investigate the potential of Tryptone stabilised silver nanoparticles (Ts-AgNPs) on planktonic and biofilms produced by Klebsiella pneumoniae and Pseudomonas aeruginosa. The MIC50 of Ts-AgNPs was found to be as low as 1.7 μg/mL and 2.7 μg/mL for K. pneumoniae and P.aeruginosa respectively. Ts-AgNPs ability to alter redox environment by producing intracellular ROS, time-kill curves showing substantial decrease in the bacterial growth and significantly reduced colony forming units further validate its antimicrobial effect. The biofilm inhibition and eradication ability of Ts-AgNPs was found to be as high as 93% and 97% in both the tested organisms. A significant decrease in the eDNA and EPS quantity in Ts-AgNPs treated cells proved its ability to successfully distort the matrix and matured biofilms. Interestingly Ts-AgNPs also attenuated QS-induced virulence factors production,. This study paves way to develop Ts-AgNPs as novel antibiotics against respiratory tract infections causing bacterial biofilms. .}, } @article {pmid38362607, year = {2024}, author = {Li, H and Han, Y and Zhang, Y and Mi, X and Wang, D and Xu, Y and Dong, K}, title = {Optimization of nitrogen removal and microbial mechanism of a hydrogen-based membrane biofilm reactor.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/09593330.2024.2317817}, pmid = {38362607}, issn = {1479-487X}, abstract = {The hydrogen-based membrane biofilm reactor (H2-MBfR) is an emerging biological nitrogen removal technology characterized by high efficiency, energy-saving capability, and environmental friendliness. The technology achieves denitrification and denitrogenation of microorganisms by passing hydrogen as an electron donor from inside to outside through the hollow fibre membrane module, and eventually the hydrogen reachs the biofilm attached to the surface of the fibre membrane. H2-MBfR has obtained favourable outcomes in the treatment of secondary biochemical effluent and low concentration nitrogen polluted water source. The experiment was optimized by s single-factor testing and response surface methodology-based optimization (RSM), and the optimal operational conditions were obtained as follows: an influent flow rate of 2 mL/min, hydrogen pressure of 0.04 MPa, and influent nitrate concentration of 24.29 mg/L. Under these conditions, a high nitrate removal rate of 98.25% was achieved. In addition, Proteobacteria and Bacteroidetes were the dominant bacteria in all stages, and the genus Hydrogenophaga was sufficiently enriched, occurring at 13.0%-49.0% throughout the reactor operation. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway for nitrate reduction and inorganic carbon utilization by microorganisms in the H2-MBfR was explored through comparison with the KEGG database. The results provided a mechanistic explanation for the denitrification and carbon sequestration capacity of the H2-MBfR.}, } @article {pmid38360658, year = {2024}, author = {El Naggar, NM and Shawky, RM and Serry, FME and Emara, M}, title = {Investigating the relationship between carbapenemase production and biofilm formation in Klebsiella pneumoniae clinical isolates.}, journal = {BMC research notes}, volume = {17}, number = {1}, pages = {49}, pmid = {38360658}, issn = {1756-0500}, abstract = {OBJECTIVE: Carbapenemase production and biofilm formation in K. pneumoniae are crucial factors influencing the pathogenicity and antibiotic resistance of this bacterium. This study investigated the interplay between carbapenemase production and biofilm formation in K. pneumoniae clinical isolates.

RESULTS: The distribution of biofilm-forming ability significantly differed between carbapenemase-producing (CP-Kp) (n = 52) isolates and carbapenemase-nonproducing (CN-Kp) isolates (n = 37), suggesting a potential link between carbapenemase production and biofilm formation. All the blaNDM-1-harbouring isolates demonstrated biofilm formation, with varying levels classified as strong (33.33%), moderate (22.22%), or weak (44.45%). blaNDM-1 and blaKPC-coharbouring isolates did not exhibit strong or moderate biofilm formation. blaNDM-1 and blaOXA-48-coharbouring isolates were predominantly moderate (48.65%), followed by weak (32.43%), with none showing strong biofilm production. These findings suggest a correlation between the presence of carbapenemases and biofilm-forming ability; however, the heterogeneity in biofilm-forming abilities associated with different carbapenemase types and the absence of strong biofilm producers in the detected carbapenemase combinations prompt a closer look at the complex regulatory mechanisms governing biofilm formation in CP-Kp isolates.}, } @article {pmid38359804, year = {2024}, author = {El-Soudany, I and Attia, N and Emad, R and Rezk, S}, title = {The Effect of Citric and Ascorbic Acids as Anti-Biofilm and Anti-Capsular Agents on Multidrug Resistant Acinetobacter baumannii.}, journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre}, volume = {}, number = {}, pages = {}, doi = {10.1159/000537852}, pmid = {38359804}, issn = {1423-0151}, abstract = {OBJECTIVE: Acinetobacter baumannii (A. baumannii) is an opportunistic bacterium with multiple virulence factors, including capsule and biofilm, and is known for its high drug resistance. Anti-virulence natural substances have been suggested as novel alternatives to conventional antibiotics. We aimed to evaluate the effect of citric acid and ascorbic acid as anti-biofilm and anti-capsular agents against multidrug resistant (MDR) A. baumannii clinical isolates.

MATERIALS AND METHODS: Twenty-eight A. baumannii MDR isolates were collected from different clinical sources. The minimum inhibitory concentration (MIC) of each agent was estimated. Biofilm formation and capsule were investigated phenotypically in the absence and presence both agents at ½ and ¼ MICs. The presence of 14 adhesive and non-adhesive virulence genes was investigated.

RESULTS: Phenotypically, all the isolates were biofilm producers and were capsulated. The MIC of citric acid ranged from 1.25 to 2.5 mg/ml while that of ascorbic acid was 3 mg/ml for all isolates. Both agents showed significant reduction in biofilm and capsular thinning. Ascorbic acid showed a dose-dependent effect in both biofilm reduction and capsule thinning unlike citric acid. Four genes, papG23, sfa1, fyuA and cvaC, were absent among all isolates, while iutA was present in 100% of isolates. Other genes showed different distributions among the isolates. These virulence genes were not correlated to the antibiofilm effect of both agents. Ascorbic acid was observed to have a better effect than citric acid. This can provide a clue for a better treatment regimen including ascorbic acid against MDR A. baumannii infections. .}, } @article {pmid38359597, year = {2024}, author = {Oliveira, IM and Gomes, IB and Simões, LC and Simões, M}, title = {A review of research advances on disinfection strategies for biofilm control in drinking water distribution systems.}, journal = {Water research}, volume = {253}, number = {}, pages = {121273}, doi = {10.1016/j.watres.2024.121273}, pmid = {38359597}, issn = {1879-2448}, abstract = {The presence of biofilms in drinking water distribution systems (DWDS) is responsible for water quality deterioration and a possible source of public health risks. Different factors impact the biological stability of drinking water (DW) in the distribution networks, such as the presence and concentration of nutrients, water temperature, pipe material composition, hydrodynamic conditions, and levels of disinfectant residual. This review aimed to evaluate the current state of knowledge on strategies for DW biofilm disinfection through a qualitative and quantitative analysis of the literature published over the last decade. A systematic review method was performed on the 562 journal articles identified through database searching on Web of Science and Scopus, with 85 studies selected for detailed analysis. A variety of disinfectants were identified for DW biofilm control such as chlorine, chloramine, UV irradiation, hydrogen peroxide, chlorine dioxide, ozone, and others at a lower frequency, namely, electrolyzed water, bacteriophages, silver ions, and nanoparticles. The disinfectants can impact the microbial communities within biofilms, reduce the number of culturable cells and biofilm biomass, as well as interfere with the biofilm matrix components. The maintenance of an effective residual concentration in the water guarantees long-term prevention of biofilm formation and improves the inactivation of detached biofilm-associated opportunistic pathogens. Additionally, strategies based on multi-barrier processes by optimization of primary and secondary disinfection combined with other water treatment methods improve the control of opportunistic pathogens, reduce the chlorine-tolerance of biofilm-embedded cells, as well as decrease the corrosion rate in metal-based pipelines. Most of the studies used benchtop laboratory devices for biofilm research. Even though these devices mimic the conditions found in real DWDS, future investigations on strategies for DW biofilm control should include the validity of the promising strategies against biofilms formed in real DW networks.}, } @article {pmid38359476, year = {2024}, author = {Pietrelli, L}, title = {Fate of the biofilm chips overflowed from a wastewater treatment plant.}, journal = {Marine pollution bulletin}, volume = {200}, number = {}, pages = {116142}, doi = {10.1016/j.marpolbul.2024.116142}, pmid = {38359476}, issn = {1879-3363}, abstract = {In February 2018 over 100 millions of polyethylene biofilm chips overflowed from a wastewater treatment plant located at Capaccio Paestum (Italy) and due to the Thyrrhenian Sea currents, in few days they invaded the coasts of Campania, Lazio and Tuscany. During the following months the diffusion involves all the coasts of the western Mediterranean, including Spain, France and Tunisia. Samples of chips were recovered mainly along the Latium coasts (Italy) during the last 6 years. Following the exposure of the biofilm chips to the environmental conditions, the effect of natural weathering on polyethylene have been studied. The following annual decreases were evaluated: thickness 9.5 μm, diameter 18.5 μm and weight 3.7 mg while the average value of the size of all recovered items (n = 60) are: thickness = 2.936 ± 0.0406 mm, diameter = 44.349 ± 0.1266 mm and weight = 1.1593 ± 0.0248 g. Considering the weight loss, it was calculated that the complete mineralization of the disks will occur in 310 years producing about 0.5 tons of microplastics per year. FTIR analysis was used to investigate the change of chemical structure of the polyethylene. The Carbonyl index (CI), Vinyl index (VI) and Hydroxyl normalized absorbance peak were used to evaluate the polymer degradation while Scanning Electron Microscopy (SEM) was used to characterize the surface of the polymer samples. It was observed that erosion/degradation increases with time spent in the environment, above all from the last two years. The static contact angle was always >90° confirming that the surface of the biofilm chip is hydrophilic. The Oxygen/Carbon ratio increase with time: 0.18 and 0.27 has been found for 2018 and 2023 disks respectively confirming the progressive oxidative process. From TGA analysis a slightly reduction of decomposition temperature has been evaluated.}, } @article {pmid38358017, year = {2024}, author = {Sharifi, A and Mahmoudi, P and Sobhani, K}, title = {The prevalence of adhesion and biofilm genes in Staphylococcus aureus isolates from bovine mastitis: A comprehensive meta-analysis.}, journal = {Veterinary medicine and science}, volume = {10}, number = {2}, pages = {e31378}, doi = {10.1002/vms3.1378}, pmid = {38358017}, issn = {2053-1095}, abstract = {BACKGROUND: Mastitis poses significant challenges to the dairy industry, resulting in economic losses and increased veterinary expenses. Staphylococcus aureus is a common cause of bovine mastitis, relying on efficient adhesion and biofilm formation for infection.

OBJECTIVES: This study aimed to employ meta-analysis to investigate the occurrence of adhesion and biofilm genes in S. aureus associated with bovine mastitis, as documented in previous studies.

METHODS: This meta-analysis was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses, examined 22 eligible articles and revealed varying prevalence rates of adhesion and biofilm genes in S. aureus isolates from bovine mastitis.

RESULTS: Among the genes, clfB showed the highest prevalence (p-estimate = 0.905), followed by fnbA (p-estimate = 0.689) and fnbB (p-estimate = 0.502). The icaA and icaD genes also showed a relatively high prevalence (p-estimate = 0.694 and 0.814, respectively). Conversely, the biofilm-associated proteins gene had the lowest prevalence (p-estimate = 0.043). Subgroup analyses based on mastitis types and publication years revealed no significant differences in gene prevalence. Insufficient data hindered the analysis of fib, sasG , eno and bbp genes.

CONCLUSION: This study provides valuable insights for managing S. aureus-induced bovine mastitis. Additionally, larger-scale research, particularly on less-studied genes, is necessary to comprehend the molecular roles of adhesion and biofilm genes in S. aureus-induced bovine mastitis.}, } @article {pmid38354989, year = {2024}, author = {Ji, Y and Han, J and Moses, M and Wang, D and Wu, L and Xue, W and Sun, L and Xu, B and Chen, C and Xiang, Y and Huang, X}, title = {The antimicrobial property of JY-1, a complex mixture of Traditional Chinese Medicine, is linked to it abilities to suppress biofilm formation and disrupt membrane permeability.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106573}, doi = {10.1016/j.micpath.2024.106573}, pmid = {38354989}, issn = {1096-1208}, abstract = {The substantial increase of infections, caused by novel, sudden, and drug-resistant pathogens, poses a significant threat to human health. While numerous studies have demonstrated the antibacterial and antiviral effects of Traditional Chinese Medicine, the potential of a complex mixture of traditional Chinese Medicine with a broad-spectrum antimicrobial property remains underexplored. This study aimed to develop a complex mixture of Traditional Chinese Medicine (TCM), JY-1, and investigate its antimicrobial properties, along with its potential mechanism of action against pathogenic microorganisms. Antimicrobial activity was assessed using a zone of inhibition assay and the drop plate method. Hyphal induction of Candida albicans was conducted using RPMI1640 medium containing 10% FBS, followed by microscopic visualization. Quantitative real-time PCR (RT-qPCR) was employed to quantify the transcript levels of hyphal-specific genes such as HWP1 and ALS3. The impact of JY-1 on biofilm formation was evaluated using both the XTT reduction assay and scanning electron microscopy (SEM). Furthermore, the cell membrane integrity was assessed by protein and nucleic acid leakage assays. Our results clearly showed that JY-1 significantly inhibits the vegetative growth of Candidaspp. and Cryptococcusspp. In addition, this complex mixture is effectively against a wide range of pathogenic bacteria, including Staphylococcus aureus, Vancomycin-resistant enterococci, Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae. More interestingly, JY-1 plays a direct anti-viral role against the mammalian viral pathogen vesicular stomatitis virus (VSV). Further mechanistic studies indicate that JY-1 acts to reduce the expression of hyphal specific genes HWP1 and ALS3, resulting in the suppression of the hyphal formation of C. albicans. The antimicrobial property of JY-1 could be attributed to its ability to reduce biofilm formation and disrupt the cell membrane permeability, a process resulting in microbial cell death and the release of cellular contents. Taken together, our work identified a potent broad-spectrum antimicrobial agent, a complex mixture of TCM which might be developed as a potential antimicrobial drug.}, } @article {pmid38354988, year = {2024}, author = {Selvaraj, K and Venkatesan, L and Ganapathy, D and Sathishkumar, P}, title = {Treatment of dental biofilm-forming bacterium Streptococcus mutans using tannic acid-mediated gold nanoparticles.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106568}, doi = {10.1016/j.micpath.2024.106568}, pmid = {38354988}, issn = {1096-1208}, abstract = {Biosynthesized gold nanoparticles (AuNPs) are highly attracted as a biocompatible nanodrug to treat various diseased conditions in humans. In this study, phytochemical tannic acid-mediated AuNPs (TA-AuNPs) are successfully synthesized and tested for antibacterial and antibiofilm activity against dental biofilm-forming Streptococcus mutans biofilm. The synthesized TA-AuNPs are appeared as spherical in shape with an average size of 19 nm. The antibacterial potential of TA-AuNPs was evaluated using ZOI and MIC measurements; while, antibiofilm efficacy was measured by checking the eradication of preformed biofilm on the tooth model. The ZOI and MIC values for TA-AuNPs are 25 mm in diameter and 4 μg/mL, respectively. The MTT assay, CLSM, and SEM results demonstrate that the preformed S. mutans biofilm is completely eradicated at 4xMIC (16 μg/mL) of TA-AuNPs. Finally, the present study reveals that the synthesized TA-AuNPs might be a great therapeutic drug to treat dental biofilm-forming bacterium S. mutans.}, } @article {pmid38353831, year = {2024}, author = {Zafer, MM and Mohamed, GA and Ibrahim, SRM and Ghosh, S and Bornman, C and Elfaky, MA}, title = {Biofilm-mediated infections by multidrug-resistant microbes: a comprehensive exploration and forward perspectives.}, journal = {Archives of microbiology}, volume = {206}, number = {3}, pages = {101}, pmid = {38353831}, issn = {1432-072X}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; *Bacteriophages ; Biofilms ; *Cross Infection ; *Cystic Fibrosis ; }, abstract = {A biofilm is a collection of microorganisms organized in a matrix of extracellular polymeric material. Biofilms consist of microbial cells that attach to both surfaces and each other, whether they are living or non-living. These microbial biofilms can lead to hospital-acquired infections and are generally detrimental. They possess the ability to resist the human immune system and antibiotics. The National Institute of Health (NIH) states that biofilm formation is associated with 65% of all microbial illnesses and 80% of chronic illnesses. Additionally, non-device-related microbial biofilm infections include conditions like cystic fibrosis, otitis media, infective endocarditis, and chronic inflammatory disorders. This review aims to provide an overview of research on chronic infections caused by microbial biofilms, methods used for biofilm detection, recent approaches to combat biofilms, and future perspectives, including the development of innovative antimicrobial strategies such as antimicrobial peptides, bacteriophages, and agents that disrupt biofilms.}, } @article {pmid38352786, year = {2024}, author = {Mohammed, HS and Ibrahim, MH and Abdel-Aziz, MM and Ghareeb, MA}, title = {Anti-Helicobacter pylori, anti-biofilm activity, and molecular docking study of citropten, bergapten, and its positional isomer isolated from Citrus sinensis L. leaves.}, journal = {Heliyon}, volume = {10}, number = {3}, pages = {e25232}, pmid = {38352786}, issn = {2405-8440}, abstract = {INTRODUCTION: Citrus sinensis L. is a candidate plant with promising antimicrobial potential. In the current study, the phytochemical investigation of C. sinensis leaf extract led to the isolation of three coumarins, namely bergapten, xanthotoxin, and citropten.

METHODS: The chemical structures of the isolated coumarins were elucidated using NMR and ESI-MS techniques. The total aqueous ethanol leaf extract and the isolated coumarins were evaluated for their antimicrobial effects against Helicobacter pylori using the MTT-micro-well dilution method and its anti-biofilm activity using MBEC assay, as compared to clarithromycin.

RESULTS: The results showed that citropten scored the lowest MIC value at 3.9 μg/mL and completely inhibited the planktonic growth of H. pylori. In addition, it completely suppressed H. pylori biofilm at 31.25 μg/mL. These findings have been supported by molecular docking studies on the active sites of the H. pylori inosine 5'-monophosphate dehydrogenase (HpIMPDH) model and the urease enzyme, showing a strong binding affinity of citropten to HpIMPDH with seven hydrogen bonds and a binding energy of -6.9 kcal/mol. Xanthotoxin and bergapten showed good docking scores, both at -6.5 kcal/mol for HpIMPDH, with each having four hydrogen bondings. Furthermore, xanthotoxin showed many hydrophobic interactions, while bergapten formed one Pi-anion interaction. Concerning docking in the urease enzyme, the compounds showed mild to moderate binding affinities as compared to the ligand. Thus, based on docking results and good binding scores observed with the HpIMPDH active site, an in-vitro HpIMPDH inhibition assay was done for the compounds. Citropten showed the most promising inhibitory activity with an IC50 value of 2.4 μM. Conclusion: The present study demonstrates that C. sinensis L. leaves are a good source for supplying coumarins that can act as naturally effective anti-H. pylori agents.}, } @article {pmid38352512, year = {2024}, author = {Furtado, KL and Plott, L and Markovetz, M and Powers, D and Wang, H and Hill, DB and Papin, J and Allbritton, NL and Tamayo, R}, title = {Clostridioides difficile -mucus interactions encompass shifts in gene expression, metabolism, and biofilm formation.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2024.02.01.578425}, pmid = {38352512}, abstract = {UNLABELLED: In a healthy colon, the stratified mucus layer serves as a crucial innate immune barrier to protect the epithelium from microbes. Mucins are complex glycoproteins that serve as a nutrient source for resident microflora and can be exploited by pathogens. We aimed to understand how the intestinal pathogen, Clostridioides diffiicile , independently uses or manipulates mucus to its benefit, without contributions from members of the microbiota. Using a 2-D primary human intestinal epithelial cell model to generate physiologic mucus, we assessed C. difficile- mucus interactions through growth assays, RNA-Seq, biophysical characterization of mucus, and contextualized metabolic modeling. We found that host-derived mucus promotes C. difficile growth both in vitro and in an infection model. RNA-Seq revealed significant upregulation of genes related to central metabolism in response to mucus, including genes involved in sugar uptake, the Wood-Ljungdahl pathway, and the glycine cleavage system. In addition, we identified differential expression of genes related to sensing and transcriptional control. Analysis of mutants with deletions in highly upregulated genes reflected the complexity of C. difficile -mucus interactions, with potential interplay between sensing and growth. Mucus also stimulated biofilm formation in vitro , which may in turn alter viscoelastic properties of mucus. Context-specific metabolic modeling confirmed differential metabolism and predicted importance of enzymes related to serine and glycine catabolism with mucus. Subsequent growth experiments supported these findings, indicating mucus is an important source of serine. Our results better define responses of C. difficile to human gastrointestinal mucus and highlight a flexibility in metabolism that may influence pathogenesis.

IMPORTANCE: Clostridioides difficile results in upwards of 250,000 infections and 12,000 deaths annually in the United States. Community-acquired infections continue to rise and recurrent disease is common, emphasizing a vital need to understand C. difficile pathogenesis. C. difficile undoubtedly interacts with colonic mucus, but the extent to which the pathogen can independently respond to and take advantage of this niche has not been explored extensively. Moreover, the metabolic complexity of C. difficile remains poorly understood, but likely impacts its capacity to grow and persist in the host. Here, we demonstrate that C. difficile uses native colonic mucus for growth, indicating C. difficile possesses mechanisms to exploit the mucosal niche. Furthermore, mucus induces metabolic shifts and biofilm formation in C. difficile , which has potential ramifications for intestinal colonization. Overall, our work is crucial to better understand dynamics of C. difficile -mucus interactions in the context of the human gut.}, } @article {pmid38351614, year = {2024}, author = {Xu, Y and Wu, Y and Rittmann, B}, title = {Describing Chemical Migration Processes at the Sediment-Periphytic Biofilm-Water Interface.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.4c00178}, pmid = {38351614}, issn = {1520-5851}, } @article {pmid38350744, year = {2024}, author = {Hamza, B and Eliades, T and Attin, T and Schwendener, S and Karygianni, L}, title = {Initial bacterial adherence and biofilm formation on novel restorative materials used in paediatric dentistry.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.dental.2024.02.002}, pmid = {38350744}, issn = {1879-0097}, abstract = {OBJECTIVE: To evaluate the initial bacterial adherence and biofilm formation on novel restorative materials in paediatric dentistry and compare the results to stainless steel crown and primary enamel.

MATERIALS AND METHODS: Twenty-five samples (Diameter = 4 mm) from five restorative materials (Tetric Power Fill light cured for 3 s or 10 s, Fuji II LC, Equia Forte HT Fil, Cention Forte, Stainless-steel crown) and primary enamel were prepared. Four samples served for recording of surface roughness (Ra) using a contact profilometer, 21 samples were incubated in stimulated human saliva for 2 h (initial bacterial adherence) and 72 h (biofilm formation) and served to determine ion releasing and bacterial growth. After 2 and 72 h, the number of colony-forming units (CFU) per ml was counted and expressed in Log10 CFU/ml. Data were analysed with two-way ANOVA and Tuckey's multiple comparisons test (p < 0.05).

RESULTS: All tested materials showed similar initial bacterial adherence (p > 0.1). Stainless steel crown showed statistically significantly less biofilm formation than all other tested materials (p ≤ 0.02), except for Fuji II LC (p = 0.06). In terms of biofilm formation, the differences between all tested materials were not statistically significant (p ≥ 0.9).

SIGNIFICANCE: Novel restorative materials in paediatric dentistry show similar initial bacterial adherence and biofilm formation. However, compared to other restorative materials, stainless steel crowns demonstrate the lowest level of biofilm formation. Ion-releasing materials may not necessarily show better antimicrobial properties than conventional materials.}, } @article {pmid38350204, year = {2024}, author = {Sharma, K and Sharma, M}, title = {Invitro anti-biofilm activity and the artificial chaperone activity of quinoline-based ionic liquids.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {235}, number = {}, pages = {113773}, doi = {10.1016/j.colsurfb.2024.113773}, pmid = {38350204}, issn = {1873-4367}, abstract = {The maintenance of protein conformation under stressful conditions is one of the prevailing challenges. This has led to a rapid growth in the ingenious protein therapies, in the past few decades, prioritizing the investigation of the structure and function of proteins in novel environments. Ionic Liquids (ILs) are currently dominating the biomedical industry, by endowing great solubility and stability to bio-molecules, especially proteins. Recently, researchers have devoted their attention towards the artificial chaperone activity of several classes of ILs. Thus, comprehending the long-term as well as momentary stability of protein conformation in IL formulations is an absolute necessity. In this context, we present the activity of quinoline-based ionic liquids (ILs) as artificial cheperones against time-dependent, self induced fibril formation in Bovine Serum Albumin (BSA). Herein, a series of quinoline-based ILs were synthesized and characterized. The structural and morphological changes induced in BSA in the presence and absence of these ILs are corroborated using several spectroscopic measurements and in-silico studies. The anti-microbial and antibiofilm activity of these compounds demonstrating their medicinal properties is substantiated in this study. Furthermore, the present research also gives an account of the toxicity of these compounds under in vivo conditions, using C. elegans as the model organism.}, } @article {pmid38349812, year = {2024}, author = {Byeon, CH and Hansen, KH and Jeffrey, J and Saricayir, H and Andreasen, M and Akbey, Ü}, title = {Intrinsically disordered Pseudomonas chaperone FapA slows down the fibrillation of major biofilm-forming functional amyloid FapC.}, journal = {The FEBS journal}, volume = {}, number = {}, pages = {}, doi = {10.1111/febs.17084}, pmid = {38349812}, issn = {1742-4658}, support = {//University of Pittsburgh/ ; //UPMC CMRF/ ; //L'OREAL UNESCO For Women in Science/ ; }, abstract = {Functional bacterial amyloids play a crucial role in the formation of biofilms, which mediate chronic infections and contribute to antimicrobial resistance. This study focuses on the FapC amyloid fibrillar protein from Pseudomonas, a major contributor to biofilm formation. We investigate the initial steps of FapC amyloid formation and the impact of the chaperone-like protein FapA on this process. Using solution nuclear magnetic resonance (NMR), we recently showed that both FapC and FapA are intrinsically disordered proteins (IDPs). Here, the secondary structure propensities (SSPs) are compared to alphafold (DeepMind, protein structure prediction tool/algorithm: https://alphafold.ebi.ac.uk/) models. We further demonstrate that the FapA chaperone interacts with FapC and significantly slows down the formation of FapC fibrils. Our NMR titrations reveal ~ 18% of the resonances show FapA-induced chemical shift perturbations (CSPs), which has not been previously observed, the largest being for A82, N201, C237, C240, A241, and G245. These sites may suggest a specific interaction site and/or hotspots of fibrillation inhibition/control interface at the repeat-1 (R1)/loop-2 (L2) and L2/R3 transition areas and at the C-terminus of FapC. Remarkably, ~ 90% of FapA NMR signals exhibit substantial CSPs upon titration with FapC, the largest being for S63, A69, A80, and I92. A temperature-dependent effect of FapA was observed on FapC by thioflavin T (ThT) and NMR experiments. This study provides a detailed understanding of the interaction between the FapA and FapC, shedding light on the regulation and slowing down of amyloid formation, and has important implications for the development of therapeutic strategies targeting biofilms and associated infections.}, } @article {pmid38349175, year = {2024}, author = {Tran, P and Lander, SM and Prindle, A}, title = {Active pH regulation facilitates Bacillus subtilis biofilm development in a minimally buffered environment.}, journal = {mBio}, volume = {}, number = {}, pages = {e0338723}, doi = {10.1128/mbio.03387-23}, pmid = {38349175}, issn = {2150-7511}, abstract = {Biofilms provide individual bacteria with many advantages, yet dense cellular proliferation can also create intrinsic metabolic challenges including excessive acidification. Because such pH stress can be masked in buffered laboratory media-such as MSgg commonly used to study Bacillus subtilis biofilms-it is not always clear how such biofilms cope with minimally buffered natural environments. Here, we report how B. subtilis biofilms overcome this intrinsic metabolic challenge through an active pH regulation mechanism. Specifically, we find that these biofilms can modulate their extracellular pH to the preferred neutrophile range, even when starting from acidic and alkaline initial conditions, while planktonic cells cannot. We associate this behavior with dynamic interplay between acetate and acetoin biosynthesis and show that this mechanism is required to buffer against biofilm acidification. Furthermore, we find that buffering-deficient biofilms exhibit dysregulated biofilm development when grown in minimally buffered conditions. Our findings reveal an active pH regulation mechanism in B. subtilis biofilms that could lead to new targets to control unwanted biofilm growth.IMPORTANCEpH is known to influence microbial growth and community dynamics in multiple bacterial species and environmental contexts. Furthermore, in many bacterial species, rapid cellular proliferation demands the use of overflow metabolism, which can often result in excessive acidification. However, in the case of bacterial communities known as biofilms, these acidification challenges can be masked when buffered laboratory media are employed to stabilize the pH environment for optimal growth. Our study reveals that B. subtilis biofilms use an active pH regulation mechanism to mitigate both growth-associated acidification and external pH challenges. This discovery provides new opportunities for understanding microbial communities and could lead to new methods for controlling biofilm growth outside of buffered laboratory conditions.}, } @article {pmid38348578, year = {2024}, author = {Khorramdel, M and Ghadikolaii, FP and Hashemy, SI and Javid, H and Tabrizi, MH}, title = {Nanoformulated meloxicam and rifampin: inhibiting quorum sensing and biofilm formation in Pseudomonas aeruginosa.}, journal = {Nanomedicine (London, England)}, volume = {}, number = {}, pages = {}, doi = {10.2217/nnm-2023-0268}, pmid = {38348578}, issn = {1748-6963}, abstract = {Background: We aimed to investigate the simultaneous effects of meloxicam and rifampin nanoformulations with solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) substrates on inhibiting the quorum-sensing system of Pseudomonas aeruginosa and preventing biofilm formation by this bacterium. Methods: Antimicrobial activity of rifampin and meloxicam encapsulated with SLNs and NLCs against P. aeruginosa PAO1 was assessed by disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results: The SLN formulation was associated with lower doses for the MIC and minimum bactericidal concentration in comparison to NLC. Moreover, our results demonstrated that both nanoformulations were able to produce 100% inhibition of the biofilm formation of P. aeruginosa PAO1. Conclusion: All these findings suggest that meloxicam and rifampin encapsulated with SLNs could be the most effective formulation against P. aeruginosa.}, } @article {pmid38347125, year = {2024}, author = {Du Toit, A}, title = {Bacterial architects build the biofilm structures.}, journal = {Nature reviews. Microbiology}, volume = {}, number = {}, pages = {}, pmid = {38347125}, issn = {1740-1534}, } @article {pmid38346622, year = {2024}, author = {Thakur, R and Yadav, S}, title = {Biofilm forming, exopolysaccharide producing and halotolerant, bacterial consortium mitigates salinity stress in Triticum aestivum.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {130049}, doi = {10.1016/j.ijbiomac.2024.130049}, pmid = {38346622}, issn = {1879-0003}, abstract = {Biofilm and EPS characterization of a rhizobacterial isolate BC-II-20 was done using biophysical techniques. SEM revealed surface morphology of EPS powder to be irregular porous web-like structure. FTIR spectra showed peaks of the polymeric carbohydrate functional groups with probable role in imparting biological properties to EPS. XRD analysis showed signal at 22[0] (2θ) and confirms its amorphous or semi-crystalline nature. EPS derived from bacterial consortium gradually increased under 200 mM, 400 mM, 600 mM and 800 mM NaCl and SEM-EDAX analysis of EPS showed increase in Na & Cl peaks under the above salt concentrations, depicting EPS-NaCl binding. Triticum aestivum plants under 200 mM NaCl stress with different combinations of treatments showed that bacterial consortium provides tolerance. Under 200 mM salt stress the shoot length was 7.74 cm and total chlorophyll was 4.16 mg g[-1]Fw of the uninoculated plants whereas inoculated ones were 9.94 cm and 5.62 mg g[-1]Fw respectively. Under salinity stress, membrane stability index was increased from 47 % to 61 % and electrolyte leakage was decreased to 48 % from 64 %, after inoculation with bacterial consortium. Therefore, consortium comprising of these halotolerant and biofilm forming, EPS producing bioinoculants provides salt tolerance and can be exploited as a sustainable alternative for stress tolerance.}, } @article {pmid38346621, year = {2024}, author = {An, N and Li, K and Wang, Y and Shen, W and Huang, X and Xu, S and Wu, L and Huang, H}, title = {Biodegradable bio-film based on Cordyceps militaris and metal-organic frameworks for fruit preservation.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {130095}, doi = {10.1016/j.ijbiomac.2024.130095}, pmid = {38346621}, issn = {1879-0003}, abstract = {In this study, Cordyceps militaris matrix was employed for the first time to fabricate a biodegradable food packaging. Carmine and Ag@CuBTC were introduced to cross-link with mycelium and were uniformly dispersed within the matrix to enhance the water resistance, antimicrobial, and antioxidant properties of the bio-films. The bio-film displayed high biodegradability, with nearly 100 % degradation achieved after three weeks. The bio-film exhibited exceptional resistance to oxidation (49.30 % DPPH and 93.94 % ABTS•[+]), as well as effective inhibitory capabilities against E. coli and S. aureus, respectively. The composite film maintained a high CO2/O2 selective permeability, which was advantageous for mitigating fruit metabolism and extending shelf life. Simultaneously, food preservation experiments confirmed that these bio-films can decelerate the spoilage of fruits and effectively prolong the shelf-life of food. The experimental findings indicated that the prepared Bio-R-Ag@Cu film held promise as an environmentally friendly biodegradable material for food packaging.}, } @article {pmid38346613, year = {2024}, author = {Gouda, M and Khalaf, MM and Abou Taleb, MF and Abd El-Lateef, HM}, title = {Fabrication of silver nanoparticles loaded acacia gum/chitosan nanogel to coat the pipe surface for sustainable inhibiting microbial adhesion and biofilm growth in water distribution systems.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {130085}, doi = {10.1016/j.ijbiomac.2024.130085}, pmid = {38346613}, issn = {1879-0003}, abstract = {Biofilm formation on the inner surfaces of pipes poses significant threats to water distribution systems, increasing maintenance costs and compromising public health. To address this immense issue, we synthesized a nanogel comprising acacia gum (AG) and chitosan (Cs), loaded with varying concentrations of silver nanoparticles (AgNPs), for use as an antimicrobial coating. AgNPs were synthesized using AG as a reducing and stabilizing agent, exhibiting absorbance at 414 nm. The homogeneous particles of AgNPs were confirmed using TEM. Bactericidal efficacy was assessed against E. coli, Klebsiella pneumoniae, Enterococcus faecalis, and Bacillus subtilis. Using the dipping coating method, two pipe materials (polypropylene (PP) and ductile iron (DI)) were coated, revealing smaller inhibition zones for Gram-positive bacteria. Notably, AgNPs2@AGCsNG nanogel exhibited potent antibacterial action. Toxicity tests confirmed nanogel safety, suggesting broad applications. High EC50% values underscored their non-toxic nature. This research proposes an effective strategy for biofilm prevention in water systems, offering excellent antibacterial properties and biocompatibility. AG and Cs nanogels loaded with AgNPs promise to enhance water quality, reduce maintenance prices, and protect human public health in water distribution networks.}, } @article {pmid38346465, year = {2024}, author = {Arshad, M and Joshan, F and Chiniforush, N and Afrasiabi, S}, title = {Comparative study of the effect of different exposure parameters of 635 nm diode laser and toluidine blue O in eliminating Aggregatibacter actinomycetemcomitans biofilm from titanium implant surfaces.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {}, number = {}, pages = {104012}, doi = {10.1016/j.pdpdt.2024.104012}, pmid = {38346465}, issn = {1873-1597}, abstract = {BACKGROUND: The aim of this study was to investigate the effects of antimicrobial photodynamic therapy (PDT) using 635 nm diode laser irradiation with an energy density of 6 to 30 J/cm[2] and toluidine blue O (TBO) as a photosensitizer on the viability of Aggregatibacter actinomycetemcomitans attached to the surface of titanium implants.

MATERIALS AND METHODS: Titanium implants contaminated with A. actinomycetemcomitans were treated with TBO alone or in combination with different exposure parameters (light doses of 6 - 30 J/cm[2] at 635 nm) and 0.2% chlorhexidine (CHX). After treatment, colony forming units (CFUs)/ml were determined to assess PDT efficacy. The structure of the biofilm of A. actinomycetemcomitans was analyzed by field emission scanning electron microscopy (FESEM).

RESULTS: Under optimal conditions, the colony count was reduced by ∼90%. Treatment with CHX was somewhat more effective (colony formation was reduced by ∼95%), but this agent has adverse effects that can be avoided with PDT.

CONCLUSION: This study confirms the efficacy of PDT against A. actinomycetemcomitans depending on the light dose. Treatment with TBO + 635 nm diode laser has an effect that may be equivalent to that of CHX, but perhaps with fewer adverse effects.}, } @article {pmid38345976, year = {2024}, author = {Musafer, HK and Jaafar, FN and Alkhafaji, MHM}, title = {The Correlation between Adhesion Genes and Biofilm Formation among Escherichia coli Clinical Isolates.}, journal = {Clinical laboratory}, volume = {70}, number = {2}, pages = {}, doi = {10.7754/Clin.Lab.2023.230525}, pmid = {38345976}, issn = {1433-6510}, abstract = {BACKGROUND: The adhesion genes are responsible for biofilm production which leads to chronic diseases like urinary tract infections (UTIs). Uropathogenic Escherichia coli (UPEC) is the most predominant pathogen involved in UTIs. This study aims to evaluate the relationship between adhesion genes and bacterial biofilm that form by UPEC.

METHODS: Fifty clinical isolates of E. coli from patients infected with UTIs were identified and antimicrobial resistance was tested by MIC assay. A polymerase chain reaction (PCR), a quick and sensitive assay to identify the adhesions operon (Afa, papG, flu, and fimH), was developed using eight primers and used for amplification. E. coli K-12 strain and E. coli J96 were used as a negative and a positive control for detection of adhesion genes.

RESULTS: The study reported 70% of isolates produce strong biofilm. Adhesion genes showed as follow Afa (64% n = 33), papG (42% n = 23), flu (94% n = 52), fimH (86% n = 45).

CONCLUSIONS: The resistance to non-Beta lactam antibiotic was significantly correlated with the availability of genes that encode for adhesion. These genes were highly correlated to biofilm formation in E. coli clinical isolates.}, } @article {pmid38345624, year = {2024}, author = {Gao, Z and Wang, Y and Chen, H and Lv, Y}, title = {Facilitating nitrification and biofilm formation of Vibrio sp. by N-acyl-homoserine lactones in high salinity environment.}, journal = {Bioprocess and biosystems engineering}, volume = {}, number = {}, pages = {}, pmid = {38345624}, issn = {1615-7605}, support = {2021SX-AT004//Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering/ ; 202103021223099//Shanxi Province Science Foundation for Youths/ ; 20210302124348//Shanxi Province Science Foundation for Youths/ ; 51778397//National Natural Science Foundation of China/ ; }, abstract = {The N-acyl-homoserine lactones (AHLs)-mediated quorum-sensing (QS) system played a crucial role in regulating biological nitrogen removal and biofilm formation. However, the regulatory role of AHLs on nitrogen removal bacteria in high salinity environment has remained unclear. This study evaluated the roles and release patterns of AHLs in Vibrio sp. LV-Q1 under high salinity condition. Results showed that Vibrio sp. primarily secretes five AHLs, and the AHLs activity is strongly correlated with the bacterial density. Exogenous C10-HSL and 3OC10-HSL were found to significantly enhance ammonium removal, while making a minor contribution to the growth rate. Both the C10-HSL and 3OC10-HSL promoted the biofilm formation of Vibrio sp. with an enhancement of 1.64 and 1.78 times, respectively. The scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM) observations confirmed the biofilm-enhancing effect of AHLs. Further analysis revealed that AHLs significantly improved bacterial self-aggregation and motility, as well as the level of extracellular polymeric substances (EPS). These findings provide significant guidance on construction of nitrification system at high salinity.}, } @article {pmid38345170, year = {2024}, author = {Zhu, Y and Xu, Y and Ling, Z and Zhao, C and Xu, A and He, F}, title = {The biofilm removal effect and osteogenic potential on the titanium surface by electrolytic cleaning: An in vitro comparison of electrolytic parameters and five techniques.}, journal = {Clinical oral implants research}, volume = {}, number = {}, pages = {}, doi = {10.1111/clr.14245}, pmid = {38345170}, issn = {1600-0501}, support = {//National Natural Science Foundation of China/ ; //the Key Research and Development Program of Science and Technology Department of Zhejiang Province/ ; }, abstract = {OBJECTIVES: To determine the optimal current and time of electrolytic cleaning (EC), compare its biofilm removal effect with generic treatments and evaluate the influence of EC to surface characteristics and osteogenic potential of SLA titanium (Ti) discs.

MATERIALS AND METHODS: The six-species biofilm-covered Ti discs were placed as cathodes in physiologic saline and subjected to various current and time treatments. The residual biofilms were evaluated to determine the optimal parameters. The contaminated Ti discs were randomized and treated by rotating Ti brush; ultrasonic-scaling with metal tips; ultrasonic-scaling with PEEK tips; air-polishing and EC. The residual biofilms were compared using a lipopolysaccharide kit (LPS), scanning electron microscope (SEM), confocal laser scanning microscopy and colony-forming unit counting. Non-contaminated Ti discs were treated and characterized. The bone marrow mesenchymal stem cells (BMSCs) were cultured on treated non-contaminated Ti discs. The adhesion, proliferation, alkaline phosphatase (ALP) activity and osteocalcin level of BMSCs were assessed.

RESULTS: The parameters at 0.6A5min were considered optimal. For LPS and SEM, EC promoted a significantly greater biofilm removal than the other groups. There were no changes in the Ti discs' colour, topography, roughness and chemical elements after EC, and the electrolysis-treated Ti discs obtained a super-hydrophilic surface. EC positively impacted the proliferation and ALP activity of BMSCs, surpassing the efficacy of alternative treatments.

CONCLUSIONS: EC achieves a near-complete eradication of contaminants on the SLA surface, causes no surface damage with improved hydrophilicity, and promotes the early osteogenic response of BMSCs, which makes it a promising treatment for peri-implantitis.}, } @article {pmid38344514, year = {2024}, author = {Alghamdi, N and Das, B and Hugar, SI and Sarangi, P and Garg, G and Kamatchi Subramani, S}, title = {Comparing the Biofilm Removal Capacity of NaOCl, Povidone-Iodine, Chlorhexidine, Curcumin, and Triphala as Endodontic Irrigants.}, journal = {Cureus}, volume = {16}, number = {1}, pages = {e52067}, pmid = {38344514}, issn = {2168-8184}, abstract = {BACKGROUND AND AIM: A sessile multicellular organism that is immersed in a self-produced matrix of extracellular polymeric substances and has its cells firmly attached to a surface is referred to as a microbial biofilm. When it comes to pulp and periradicular pathosis, biofilms are crucial. To reduce the number of microorganisms in the root canal and assist in treating periapical pathosis, endodontic therapy must include decontamination of the system of tooth root canals through biomechanical preparation and irrigation of the root canal. This study compares sodium hypochlorite (NaOCl), povidone-iodine, chlorhexidine, curcumin, and triphala as endodontic irrigating solutions regarding their capacity to eliminate biofilm from root canals.

MATERIALS AND METHODS: A total of 60 patients were included if they had pulpitis. Two specific samples (samples A and B) were chosen for analysis from a collection of samples so that their bacterial composition is most similar to that of acute pulpitis. The suspensions of bacterial cells from this polymicrobial culture have been collected from frozen stock and then regrown by inoculation on Columbia agar base (Basingstoke, UK) with the addition of vitamin K1, hemin, and 5% (v/v) calf blood. The pureness of the suspensions was assessed using colony morphology and Gram staining. Analytical profile index (API) 20A tests or automated test for bacteria (ATB) ID 32A tests were initially used to identify the isolates. These polymicrobial cultures' in vitro biofilms were developed using membrane filters made of cellulose nitrate. The tested irrigating solutions were as follows: 5.25% sodium hypochlorite, 10% triphala, 0.2% chlorhexidine gluconate, 10% povidone-iodine, and 5% curcumin (CUR). On the other hand, phosphate-buffered saline was taken as a control agent.

RESULTS: As the standard of excellence in endodontic irrigation, NaOCl has eliminated all germs in sample A following 15 minutes of culture and in both of the specimens after 40 minutes. Iodine also eliminated all germs after 40 minutes of administration, indicating that it would be worth exploring using iodine as a potential endodontic irrigant. Iodine achieved total bacterial elimination after 40 minutes in both samples; however, it was less effective after 15 minutes. Our findings indicate that iodine solution is the most suitable alternative after the supremely effective NaOCl, although it requires longer contact times to generate the necessary and recognized broad-spectrum antibacterial properties, including in the case of biofilms. Furthermore, curcumin also showed significant results after NaOCl and iodine.

CONCLUSION: The antibacterial potency of each studied irrigant was significant, supporting their usage in endodontics. It was observed that NaOCl has the maximum antibacterial activity.}, } @article {pmid38344162, year = {2023}, author = {Krishnakumaran, M and Mahalingam, J and Arumugam, S and Prabhu, D and Parameswaran, TM and Krishnan, B}, title = {Evaluation of the Effect of Nanocoating on Mechanical and Biofilm Formation in Thermoplastic Polyurethane Aligner Sheets.}, journal = {Contemporary clinical dentistry}, volume = {14}, number = {4}, pages = {272-276}, pmid = {38344162}, issn = {0976-237X}, abstract = {OBJECTIVE: The objective of this research is to determine whether the thermoplastic polyurethane (TPU) coated with carboxymethylcellulose chitosan has better mechanical and antibacterial action (anti-Streptococcus mutans) when utilized in intraoral simulations with synthetic saliva.

MATERIALS AND METHODS: The TPU sheets (n = 45) were divided into three groups. Control (n = 15) consists of as-received TPU sheets. Test 1 consists of TPU sheets coated with carboxymethyl cellulose (CMC) chitosan (CHI) (n = 15). Test 2 consists of thermoformed nano-coated TPU (n = 15). For the polyurethane sheets, CHI-CMC sheets, and thermoformed CHI-CMC sheets, scanning electron microscopy (SEM) and three-point flexural tests were conducted and assessed. The materials testing software was used to calculate the elastic modulus and tensile strength. To study the bacterial accumulation, the cut circles of the TPU aligner were placed in centrifuge tubes with 2.5 mL of bacterial suspension at a concentration of 104 or 105 CFU/mL. SEM was done to assess the presence of cell growth in all three groups.

RESULTS: According to SEM analyses of bacterial buildup, the coated TPU had minimal biofilms compared to the bare TPUs numerous biofilms. The effect of aging on coating thickness reveals that the thickness of thermoformed coated TPU films dramatically decreased over time, while the thickness of coated TPU films was maintained. When TPU is coated with CMC/CHI, the elastic modulus and tensile strength were observed to improve.

CONCLUSION: The development of a super-hydrophilic coating by the CHI CMC coating on TPU sheets improved the coating's biocompatibility while also changing the shape of the multilayer film to prevent bacterial adhesion. The effect on the improvement in the mechanical properties diminished after the material underwent a thermoforming process. It is therefore suggested that the nanofilm be used in therapeutic applications following the thermoforming process.}, } @article {pmid38342794, year = {2024}, author = {Mohan, A and Rajan, PP and Kumar, P and Jayakumar, D and Mini, M and Asha, S and Vaikkathillam, P}, title = {Theophylline as a quorum sensing and biofilm inhibitor in Pseudomonas aeruginosa and Chromobacterium violaceum.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {38342794}, issn = {1618-1905}, support = {P3/24770/2020/DCE//Higher Education Department (Kerala Government)/ ; P3/24770/2020/DCE//Higher Education Department (Kerala Government)/ ; P3/24770/2020/DCE//Higher Education Department (Kerala Government)/ ; }, abstract = {Quorum sensing (QS) is pivotal in coordinating virulence factors and biofilm formation in various pathogenic bacteria, making it a prime target for disrupting bacterial communication. Pseudomonas aeruginosa is a member of the "ESKAPE" group of bacterial pathogens known for their association with antimicrobial resistance and biofilm formation. The current antibiotic arsenal falls short of addressing biofilm-related infections effectively, highlighting the urgent need for novel therapeutic agents. In this study, we explored the anti-QS and anti-biofilm properties of theophylline against two significant pathogens, Chromobacterium violaceum and P. aeruginosa. The production of violacein, pyocyanin, rhamnolipid, and protease was carried out, along with the evaluation of biofilm formation through methods including crystal violet staining, triphenyl tetrazolium chloride assay, and fluorescence microscopy. Furthermore, computational analyses were conducted to predict the targets of theophylline in the QS pathways of P. aeruginosa and C. violaceum. Our study demonstrated that theophylline effectively inhibits QS activity and biofilm formation in C. violaceum and P. aeruginosa. In P. aeruginosa, theophylline inhibited the production of key virulence factors, including pyocyanin, rhamnolipid, protease, and biofilm formation. The computational analyses suggest that theophylline exhibits robust binding affinity to CviR in C. violaceum and RhlR in P. aeruginosa, key participants in the QS-mediated biofilm pathways. Furthermore, theophylline also displays promising interactions with LasR and QscR in P. aeruginosa. Our study highlights theophylline as a versatile anti-QS agent and offers a promising avenue for future research to develop novel therapeutic strategies against biofilm-associated infections.}, } @article {pmid38342369, year = {2024}, author = {Kannan, KP and Gunasekaran, V and Sreenivasan, P and Sathishkumar, P}, title = {Recent updates and feasibility of nanodrugs in the prevention and eradication of dental biofilm and its associated pathogens - a review.}, journal = {Journal of dentistry}, volume = {}, number = {}, pages = {104888}, doi = {10.1016/j.jdent.2024.104888}, pmid = {38342369}, issn = {1879-176X}, abstract = {OBJECTIVES: Dental biofilm is one of the most prevalent diseases in humans, which is mediated by multiple microorganisms. Globally, half of the human population suffers from dental biofilm and its associated diseases. In recent trends, nano-formulated drugs are highly attractive in the treatment of dental biofilms. However, the impact of different types of nanodrugs on the dental biofilm and its associated pathogens have not been published till date. Thus, this review focuses on the recent updates, feasibility, mechanisms, limitations, and regulations of nanodrugs applications in the prevention and eradication of dental biofilm.

A systematic search was conducted in PubMed/Google Scholar/Scopus over the past five years covering the major keywords "nanodrugs, metallic nanoparticles, metal oxide nanoparticles, natural polymers, synthetic polymers, biomaterials, dental biofilm, antibiofilm mechanism, dental pathogens", are reviewed in this study. Nearly, 100 scientific articles are selected in this relevant topic published between 2019-2023. Data from the selected studies dealing with nanodrugs used for biofilm treatment was qualitatively analyzed.

CONCLUSIONS: The nanodrugs such as silver nanoparticles, gold nanoparticles, selenium nanoparticles, zinc oxide nanoparticles, copper oxide nanoparticles, titanium oxide nanoparticles, hydroxyapatite nanoparticles and these inorganic nanoparticles incorporated polymer-based nanocomposites, organic/inorganic nanoparticles mediated antimicrobial photodynamic therapy exhibits an excellent antibacterial and antibiofilm activity towards dental pathogens. Finally, this review highlights that bioinspired nanodrugs will be very useful to control the dental biofilm and its associated diseases.

CLINICAL SIGNIFICANCE: Microbial influence on the oral environment is unavoidable; therefore, curing such dental biofilms and pathogens is essential for the impactful reflection of applying biocompatible treatments. In this direction, the current review explains the demand for the nanodrug in inhibiting biofilms for the effective exploration of employing treatments.}, } @article {pmid38342280, year = {2024}, author = {Lu, M and Zhao, F and Qin, F and Zhang, F and Feng, Q and Guo, R}, title = {Novel flocking materials as biocarriers in moving bed biofilm reactor for improving simultaneous nitrification and denitrification performance.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130430}, doi = {10.1016/j.biortech.2024.130430}, pmid = {38342280}, issn = {1873-2976}, abstract = {Biocarrier is the key factor for the stable operation of moving bed biofilm reactor (MBBR). To achieve efficient simultaneous nitrification and denitrification (SND), this study provided novel flocking materials as biocarriers. The biofilm formation experiment showed that longer flocking carrier was more conducive to biomass accumulation, resulting in greater oxygen uptake rate. The continuous operation results showed that the total nitrogen removal and SND performance of the MBBR with the addition of 5.0 mm flocking carriers reached 52.0 % and 70.5 %, respectively, which were 29.1 % and 33.3 % greater than those of the control. Compared with those in suspended sludge, the extracellular polymeric substances and protein components in the biocarrier were more abundant. Furthermore, the relative abundance of genera related to denitrification and the nitrogen metabolic sequence improved with the addition of the novel flocking biocarriers. This study demonstrated the effectiveness of novel flocking fillers in improving the performance of MBBR.}, } @article {pmid38342192, year = {2024}, author = {Le, PH and Linklater, DP and Medina, AA and MacLaughlin, S and Crawford, RJ and Ivanova, EP}, title = {Impact of multiscale surface topography characteristics on Candida albicans biofilm formation: from cell repellence to fungicidal activity.}, journal = {Acta biomaterialia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.actbio.2024.02.006}, pmid = {38342192}, issn = {1878-7568}, abstract = {While there has been significant research conducted on bacterial colonization on implant materials, with a focus on developing surface modifications to prevent the formation of bacterial biofilms, the study of Candida albicans biofilms on implantable materials is still in its infancy, despite its growing relevance in implant-associated infections. C. albicans fungal infections represent a significant clinical concern due to their severity and associated high fatality rate. Pathogenic yeasts account for an increasing proportion of implant-associated infections, since Candida spp. readily form biofilms on medical and dental device surfaces. In addition, these biofilms are highly antifungal-resistant, making it crucial to explore alternative solutions for the prevention of Candida implant-associated infections. One promising approach is to modify the surface properties of the implant, such as the wettability and topography of these substrata, to prevent the initial Candida attachment to the surface. This review summarizes recent research on the effects of surface wettability, roughness, and architecture on Candida spp. attachment to implantable materials. The nanofabrication of material surfaces are highlighted as a potential method for the prevention of C. albicans spp. attachment and biofilm formation on medical implant materials. Understanding the mechanisms by which Candida spp. attach to surfaces will allow such surfaces to be designed such that the incidence and severity of Candida infections in patients can be significantly reduced. Most importantly, this approach could also substantially reduce the need to use antifungals for the prevention and treatment of these infections, thereby playing a crucial role in minimizing the possibility contributing to instances of antimicrobial resistance. STATEMENT OF SIGNIFICANCE: In this review we provide a systematic analysis of the role that surface characteristics, such as wettability, roughness, topography and architecture, play on the extent of C. albicans cells attachment that will occur on biomaterial surfaces. We show that exploiting bioinspired surfaces could significantly contribute to the prevention of antimicrobial resistance to antifungal and chemical-based preventive measures. By reducing the attachment and growth of C. albicans cells using surface structure approaches, we can decrease the need for antifungals, which are conventionally used to treat such infections.}, } @article {pmid38341976, year = {2024}, author = {Ranieri, L and Esposito, R and Nunes, SP and Vrouwenvelder, JS and Fortunato, L}, title = {Biofilm rigidity, mechanics and composition in seawater desalination pretreatment employing ultrafiltration and microfiltration membranes.}, journal = {Water research}, volume = {253}, number = {}, pages = {121282}, doi = {10.1016/j.watres.2024.121282}, pmid = {38341976}, issn = {1879-2448}, abstract = {The choice of appropriate biofilm control strategies in membrane systems for seawater desalination pretreatment relies on understanding the properties of the biofilm formed on the membrane. This study reveals how the biofilm composition, including both organic and inorganic, influenced the biofilm behavior under mechanical loading. The investigation was conducted on two Gravity-Driven Membrane reactors employing Microfiltration (MF) and Ultrafiltration (UF) membrane for the pretreatment of raw seawater. After a stabilization period of 20 days (Phase I), a biofilm behavior test was introduced (Phase II) to evaluate (i) biofilm deformation during the absence of permeation (i.e., relaxation) and (ii) biofilm resistance to detachment forces (i.e., air scouring). The in-situ monitoring investigation using Optical Coherence Tomography (OCT) revealed that the biofilms developed on MF and UF membrane presented a rigid structure in absence of filtration forces, limiting the application of relaxation and biofilm expansion necessary for cleaning. Moreover, under shear stress conditions, a higher reduction in biofilm thickness was observed for MF (-60%, from 84 to 34 µm) compared to UF (-30%, from 64 to 45 µm), leading to an increase of permeate flux (+60%, from 9.1 to 14.9 L/m[2]/h and +20 % from 7.8 to 9.5 L/m[2]/h, respectively). The rheometric analysis indicated that the biofilm developed on MF membrane had weaker mechanical strength, displaying lower storage modulus (-50 %) and lower loss modulus (-55 %) compared to UF. These differences in mechanical properties were linked to the lower concentration of polyvalent ions and the distribution of organic foulants (i.e., BB, LMW-N) found in the biofilm on the MF membrane. Moreover, in the presence of air scouring led to a slight difference in microbial community between UF and MF. Our findings provide valuable insight for future investigations aimed at engineer biofilm composition to optimize biofilm control strategies in membrane systems for seawater desalination pretreatment.}, } @article {pmid38341973, year = {2024}, author = {Sun, L and Bai, Z and Yang, Q and Fu, R and Li, H and Li, X}, title = {In situ assessment of the initial phase of wastewater biofilm formation: Effect of the presence of algae in an aerobic bacterial biofilm system.}, journal = {Water research}, volume = {253}, number = {}, pages = {121283}, doi = {10.1016/j.watres.2024.121283}, pmid = {38341973}, issn = {1879-2448}, abstract = {The initial start-up attachment stage that dominates biofilm formation is an unstable process and is time-consuming. In the present study, Chlorella sp. was introduced into a general aerobic biofilm system to explore whether the addition of algae improved the initial attachment phase of biofilm. Compared with those of the bacterial biofilms, the initial algal-bacterial biofilms were more stable and had a thicker, denser, and rougher surface. Further investigation suggested that the concentration of extracellular polymeric substances (EPSs) in the algal-bacterial biofilm was 31.33 % greater than that in the bacterial biofilm. Additionally, the algal-bacterial flocs had greater free energies of absolute cohesion (ΔG[coh]) and adhesion energy (∆G[adh]) than did the bacterial flocs. These phenomena contribute to the speediness and stabilization of initial algal-bacterial start-up biofilms. Specifically, algae inoculation increased microbial community diversity and promoted the growth of bacterial members related to biofilm development. In conclusion, both physicochemical interactions and biological processes strongly influence microbial attachment during the initial biofilm formation process and further promote strengthening.}, } @article {pmid38341565, year = {2024}, author = {Mohamed, AA and Fayyad, DM and El-Telbany, M and Mohamed, DA}, title = {Antibacterial biofilm efficacy of calcium hydroxide loaded on Gum Arabic nanocarrier: an in-vitro study.}, journal = {BMC oral health}, volume = {24}, number = {1}, pages = {215}, pmid = {38341565}, issn = {1472-6831}, abstract = {BACKGROUND: An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs.

MATERIALS AND METHODS: The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance.

RESULTS: The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p < 0.001). There were significant differences in the E. faecalis CFU mean count and CT mean values between the tested groups (p < 0.001) except between the Ca(OH)2 and GA CFU mean count. Ca(OH)2-GA NPs showed the least statistical E. faecalis mean count among other groups. SEM observation showed that E. faecalis biofilm was diminished in all treatment groups, especially in the Ca(OH)2-GA NPS group when compared to the control group.

CONCLUSIONS: Ca(OH)2 and GA nanoparticles demonstrate superior anti-E. faecalis activity when compared to their conventional counterparts. Ca(OH)2-GA NPs showed the best antibacterial efficacy in treating E. faecalis biofilm. The tested NP formulations could be considered as promising intracanal medications.}, } @article {pmid38339947, year = {2024}, author = {Zeeshan, T and Qamar, Z and Abdul, NS and Soman, C and Bamousa, B and Marrapodi, MM and Cicciù, M and Minervini, G}, title = {The commercially available oral rinse vs. curcumin photosensitizers in an artificial mouth model mimicking their use after meals on early colonizers single species biofilm: An in vitro study.}, journal = {Technology and health care : official journal of the European Society for Engineering and Medicine}, volume = {}, number = {}, pages = {}, doi = {10.3233/THC-231814}, pmid = {38339947}, issn = {1878-7401}, abstract = {BACKGROUND: Commercially available oral rinses contain active ingredients with concentration that is claimed by manufacturers to be effective as antiplaque agent. To date there has been no mention of the effect of oral rinse on the adherence of early plaque colonizers in plaque formation and the concentration to be used before/after meals.

OBJECTIVE: The chief aim of the study was to evaluate microbial retention on the salivary pellicle on treatment with oral rinses (CHX & EO)/PS (mimicking after meals use of mouth wash/PS).

METHODS: Noordini's Artifical Mouth model was used for developing the single species biofilm with early microbial colonizers of oral biofilm (A. viscosus, Strep. mitis and Strep. sanguinis respectively). The microbial retention on use of oral rinses comprising of CHX and EO as an active ingredients respectively was compared with Curcumin PS. For evaluating the microbial retention, the pellicle with microbial inoculation was developed on the glass beads in the mouth model. Subsequently the respective single specie biofilm was exposed to the mouth wash and PS after inoculation. It mimicked as use of mouth wash/PS after meals. The bacterial count in the dental biofilm was evaluated on serial dilution (CFU/ml). Sterile deionized water was used as a negative control. For qualitative analysis, Scanning electron microscope (SEM) was used to evaluate the microbial count.

RESULTS: From the data it was observed that for the treatment of single species experimental biofilm with commercially available mouth rinses (CHX & EO) and PS (curcumin), there was significant retention for S.mitis, S.sanguinis and A.viscosus. There was no significant difference observed between PS and CHX treated single species biofilm. Whereas a significant difference was observed between EO treated biofilms and CHX/PS treated biofilms (p⩽ 0.05).

CONCLUSION: It can be concluded from the results that curcumin PS and CHX should not be used after meals whereas EO containing mouth rinse can be used to maintain the oral mocroflora.}, } @article {pmid38339793, year = {2024}, author = {Liu, Y and Long, S and Wang, H and Wang, Y}, title = {Biofilm therapy for chronic wounds.}, journal = {International wound journal}, volume = {21}, number = {2}, pages = {e14667}, pmid = {38339793}, issn = {1742-481X}, support = {82170887//Data Center of Management Science, National Natural Science Foundation of China - Peking University/ ; }, abstract = {Chronic wounds have been a major factor of serious harm to global public health. At present, it is known that almost all chronic wounds contain biofilms, which seriously hinder the healing process. Removal of biofilms can effectively promote the healing of chronic wounds. As the study of wound biofilms deepens, many new treatment methods have emerged, thus bringing revolutionary means for the treatment of chronic wound biofilm. This review summarizes various methods for the treatment of chronic wound biofilm worldwide to provide a theoretical summary and practical basis for the selection of suitable wound biofilm treatment methods in clinical practice.}, } @article {pmid38338675, year = {2024}, author = {Geng, X and Yang, YJ and Li, Z and Ge, WB and Xu, X and Liu, XW and Li, JY}, title = {Fingolimod Inhibits Exopolysaccharide Production and Regulates Relevant Genes to Eliminate the Biofilm of K. pneumoniae.}, journal = {International journal of molecular sciences}, volume = {25}, number = {3}, pages = {}, doi = {10.3390/ijms25031397}, pmid = {38338675}, issn = {1422-0067}, support = {2021YFD1800900//the National Key R&D Program of China/ ; 22JR5RA042//Natural Science Foundation of Gansu Province/ ; 25-LZIHPS-02//Science-Technology Innovation Engineering of CAAS/ ; }, abstract = {Klebsiella pneumoniae (K. pneumoniae) exhibits the ability to form biofilms as a means of adapting to its adverse surroundings. K. pneumoniae in this biofilm state demonstrates remarkable resistance, evades immune system attacks, and poses challenges for complete eradication, thereby complicating clinical anti-infection efforts. Moreover, the precise mechanisms governing biofilm formation and disruption remain elusive. Recent studies have discovered that fingolimod (FLD) exhibits biofilm properties against Gram-positive bacteria. Therefore, the antibiofilm properties of FLD were evaluated against multidrug-resistant (MDR) K. pneumoniae in this study. The antibiofilm activity of FLD against K. pneumoniae was assessed utilizing the Alamar Blue assay along with confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and crystal violet (CV) staining. The results showed that FLD effectively reduced biofilm formation, exopolysaccharide (EPS), motility, and bacterial abundance within K. pneumoniae biofilms without impeding its growth and metabolic activity. Furthermore, the inhibitory impact of FLD on the production of autoinducer-2 (AI-2) signaling molecules was identified, thereby demonstrating its notable anti-quorum sensing (QS) properties. The results of qRT-PCR analysis demonstrated that FLD significantly decreased the expression of genes associated with the efflux pump gene (AcrB, kexD, ketM, kdeA, and kpnE), outer membrane (OM) porin proteins (OmpK35, OmpK36), the quorum-sensing (QS) system (luxS), lipopolysaccharide (LPS) production (wzm), and EPS production (pgaA). Simultaneously, FLD exhibited evident antibacterial synergism, leading to an increased survival rate of G. mellonella infected with MDR K. pneumoniae. These findings suggested that FLD has substantial antibiofilm properties and synergistic antibacterial potential for colistin in treating K. pneumoniae infections.}, } @article {pmid38338303, year = {2024}, author = {Yang, H and Ma, R and Chen, J and Xie, Q and Luo, W and Sun, P and Liu, Z and Guo, J}, title = {Discovery of Melittin as Triple-Action Agent: Broad-Spectrum Antibacterial, Anti-Biofilm, and Potential Anti-Quorum Sensing Activities.}, journal = {Molecules (Basel, Switzerland)}, volume = {29}, number = {3}, pages = {}, doi = {10.3390/molecules29030558}, pmid = {38338303}, issn = {1420-3049}, abstract = {The development of antibiotic-resistant microorganisms is a major global health concern. Recently, there has been an increasing interest in antimicrobial peptides as a therapeutic option. This study aimed to evaluate the triple-action (broad-spectrum antibacterial, anti-biofilm, and anti-quorum sensing activities) of melittin, a membrane-active peptide present in bee venom. The minimum inhibitory concentration and minimum bactericidal concentration of the melittin were determined using the microdilution method and agar plate counting. Growth curve analysis revealed that melittin showed a concentration-dependent antibacterial activity. Scanning electron microscope analysis revealed that melittin treatment altered the morphology. Confocal laser scanning microscope revealed that melittin increased the membrane permeability and intracellular ROS generation in bacteria, all of which contribute to bacterial cell death. In addition, the crystal violet (CV) assay was used to test the anti-biofilm activity. The CV assay demonstrated that melittin inhibited biofilm formation and eradicated mature biofilms. Biofilm formation mediated by quorum sensing (QS) plays a major role in this regard, so molecular docking and molecular dynamics analysis confirmed that melittin interacts with LasR receptors through hydrogen bonds, and further evaluates the anti-QS activity of melittin through the production of virulence factors (pyocyanin, elastase, and rhamnolipid), exopolysaccharides secretion, and bacterial motility, that may be the key to inhibiting the biofilm formation mechanism. The present findings highlight the promising role of melittin as a broad-spectrum antibacterial, anti-biofilm agent, and potential QS inhibitor, providing a new perspective and theoretical basis for the development of alternative antibiotics.}, } @article {pmid38338251, year = {2024}, author = {Grassi, M and Senarighi, M and Farinelli, L and Masucci, A and Mattioli-Belmonte, M and Licini, C and Gigante, A}, title = {Early Biofilm Formation on the Drain Tip after Total Knee Arthroplasty Is Not Associated with Prosthetic Joint Infection: A Pilot Prospective Case Series Study of a Single Center.}, journal = {Healthcare (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, doi = {10.3390/healthcare12030366}, pmid = {38338251}, issn = {2227-9032}, abstract = {BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication of arthroplasties that could occur during the surgery. The purpose of this study was to analyze the biofilm formation through microbiological culture tests and scanning electron microscopy (SEM) on the tip of surgical drainage removed 24 h after arthroplasty surgery.

METHODS: A total of 50 consecutive patients were included in the present prospective observational study. Drains were removed under total aseptic conditions twenty-four hours after surgery. The drain tip was cut in three equal parts of approximately 2-3 cm in length and sent for culture, culture after sonication, and SEM analysis. The degree of biofilm formation was determined using a SEM semi-quantitative scale.

RESULTS: From the microbiological analysis, the cultures of four samples were positive. The semi-quantitative SEM analysis showed that no patient had grade 4 of biofilm formation. A total of 8 patients (16%) had grade 3, and 14 patients (28%) had grade 2. Grade 1, scattered cocci with immature biofilm, was contemplated in 16 patients (32%). Finally, 12 patients (24%) had grade 0 with a total absence of bacteria. During the follow-up (up to 36 months), no patient showed short- or long-term infectious complications.

CONCLUSIONS: Most of the patients who underwent primary total knee arthroplasty (TKA) showed biofilm formation on the tip of surgical drain 24 h after surgery even though none showed a mature biofilm formation (grade 4). Furthermore, 8% of patients were characterized by a positivity of culture analysis. However, none of the patients included in the study showed signs of PJI up to 3 years of follow-up.}, } @article {pmid38337187, year = {2024}, author = {Bhattacharya, M and Horswill, AR}, title = {The role of human extracellular matrix proteins in defining Staphylococcus aureus biofilm infections.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuae002}, pmid = {38337187}, issn = {1574-6976}, abstract = {20-41% of the world's population is either transiently or permanently colonized by the Gram-positive bacterium, Staphylococcus aureus. In 2017, the CDC designated methicillin resistant S. aureus (MRSA) as a serious threat, reporting ∼300 000 cases of MRSA-associated hospitalizations annually, resulting in over 19 000 deaths, surpassing that of HIV in the United States. S. aureus is a proficient biofilm-forming organism, which rapidly acquires resistance to antibiotics, most commonly methicillin (MRSA). This review focuses on a large group of (>30) S. aureus adhesins, either surface-associated or secreted that are designed to specifically bind to 15 or more of the proteins that form key components of the human extracellular matrix (hECM). Importantly, this includes hECM proteins that are pivotal to the homeostasis of almost every tissue environment (collagen (skin), proteoglycans (lung), hemoglobin (blood), elastin, laminin, fibrinogen, fibronectin, and fibrin (multiple organs). These adhesins offer S. aureus the potential to establish an infection in every sterile tissue niche. These infections often endure repeated immune onslaught, developing into chronic, biofilm-associated conditions that are tolerant to ∼1000 times the clinically prescribed dose of antibiotics. Depending on the infection and the immune response, this allows S. aureus to seamlessly transition from colonizer to pathogen by subtly manipulating the host against itself while providing the time and stealth that it requires to establish and persist as a biofilm. This is a comprehensive discussion of the interaction between S. aureus biofilms and the hECM. We provide particular focus on the role of these interactions in pathogenesis and consequently the clinical implications for the prevention and treatment of S. aureus biofilm infections.}, } @article {pmid38337184, year = {2024}, author = {Jakub, B and Petra, L}, title = {Current methods for monitoring Pseudomonas syringae biofilm development.}, journal = {Letters in applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/lambio/ovae013}, pmid = {38337184}, issn = {1472-765X}, abstract = {This work reviews biofilm investigation techniques and highlight the benefits and drawbacks of each approach focusing especially on Pseudomonas syringae and may serve as a comprehensive guide for any early career researchers starting with the topic of biofilm. Each approach with applications of individual microscopy and spectroscopy techniques is summarized together with characterization of Pseudomonas syringae and its role in pathogenesis.}, } @article {pmid38336925, year = {2024}, author = {Heine, N and Doll-Nikutta, K and Stein, F and Jakobi, J and Ingendoh-Tsakmakidis, A and Rehbock, C and Winkel, A and Barcikowski, S and Stiesch, M}, title = {Anti-biofilm properties of laser-synthesized, ultrapure silver-gold-alloy nanoparticles against Staphylococcus aureus.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {3405}, pmid = {38336925}, issn = {2045-2322}, support = {356685838//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Staphylococcus aureus biofilm-associated infections are a common complication in modern medicine. Due to inherent resilience of biofilms to antibiotics and the rising number of antibiotic-resistant bacterial strains, new treatment options are required. For this purpose, ultrapure, spherical silver-gold-alloy nanoparticles with homogenous elemental distribution were synthesized by laser ablation in liquids and analyzed for their antibacterial activity on different stages of S. aureus biofilm formation as well as for different viability parameters. First, the effect of nanoparticles against planktonic bacteria was tested with metabolic activity measurements. Next, nanoparticles were incubated with differently matured S. aureus biofilms, which were then analyzed by metabolic activity measurements and three dimensional live/dead fluorescent staining to determine biofilm volume and membrane integrity. It could be shown that AgAu NPs exhibit antibacterial properties against planktonic bacteria but also against early-stage and even mature biofilms, with a complete diffusion through the biofilm matrix. Furthermore, AgAu NPs primarily targeted metabolic activity, to a smaller extend membrane integrity, but not the biofilm volume. Additional molecular analyses using qRT-PCR confirmed the influence on different metabolic pathways, like glycolysis, stress response and biofilm formation. As this shows clear similarities to the mechanism of pure silver ions, the results strengthen silver ions to be the major antibacterial agent of the synthesized nanoparticles. In summary, the results of this study provide initial evidence of promising anti-biofilm characteristics of silver-gold-alloy nanoparticles and support the importance of further translation-oriented analyses in the future.}, } @article {pmid38336675, year = {2024}, author = {Jang, EY and Chun, J and Kwack, KH and Moon, JH and Lee, JH}, title = {Complete genome sequence of Schaalia odontolytica isolated from subgingival biofilm.}, journal = {BMC genomic data}, volume = {25}, number = {1}, pages = {15}, pmid = {38336675}, issn = {2730-6844}, support = {NRF-2021R1A2C2008180//National Research Foundation of Korea/ ; NRF-2022R1F1A1071248//National Research Foundation of Korea/ ; NRF-2021R1A2C2008180//National Research Foundation of Korea/ ; NRF-2022R1F1A1071248//National Research Foundation of Korea/ ; }, abstract = {OBJECTIVE: Recent advancements in genome-based taxonomic classification propose the reclassification of certain Actinomyces species into new genera, including Schaalia. Schaalia odontolytica, the type species within this genus, is frequently found in the human oral cavity and has been associated with actinomycotic lesions. Currently, only two complete genomes of S. odontolytica strains have been reported. Recognizing the limited research on subspecies-level variation of S. odontolytica, we conducted genome sequencing of strain KHUD_008, isolated from a Korean periodontitis patient's subgingival biofilm. Additionally, we performed a comparative genome analysis using previously sequenced genomes of strain XH001 and strain FDAARGOS_732, both derived from the human oral cavity.

DATA DESCRIPTION: Pacific Biosciences Sequel II sequencing generated 15,904 and 76,557 raw sequencing sub-reads, which were integrated to assemble the de novo genome using the Microbial Genome Analysis pipeline in the Single-Molecule Real-Time Analysis. The genome assembly completeness, assessed by Benchmarking Universal Single-Copy Orthologs, reached 99.2%. The genome is 2,389,595 bp with a GC content of 66.37%, and contains 2,002 protein-coding genes, 9 rRNAs, and 48 tRNA. Comparative analysis with two previously sequenced strains revealed many strain-specific genes in KHUD_008, primarily related to envelope biogenesis and replication/recombination/repair processes.}, } @article {pmid38335884, year = {2024}, author = {Li, Y and Luo, L and Wang, W and Hong, B and Ma, Y and Wang, J}, title = {Characterization of a cell wall hydrolase with high activity against vegetative cells, spores and biofilm of Bacillus cereus.}, journal = {International journal of food microbiology}, volume = {414}, number = {}, pages = {110617}, doi = {10.1016/j.ijfoodmicro.2024.110617}, pmid = {38335884}, issn = {1879-3460}, abstract = {Bacillus cereus is a prevalent foodborne pathogen that induces food poisoning symptoms such as vomiting and diarrhea. Its capacity to form spores and biofilm enables it to withstand disinfectants and antimicrobials, leading to persistent contamination during food processing. Consequently, it is necessary to develop novel and efficient antimicrobial agents to control B. cereus, its spores, and biofilms. Peptidoglycan hydrolases have emerged as a promising and eco-friendly alternative owing to their specific lytic activity against pathogenic bacteria. Here, we identified and characterized a Lysozyme-like cell wall hydrolase Lys14579, from the genome of B. cereus ATCC 14579. Recombinant Lys14579 specifically lysed B. cereus without affecting other bacteria. Lys14579 exhibited strong lytic activity against B. cereus, effectively lysing B. cereus cell within 20 min at low concentration (10 μg/mL). It also inhibited the germination of B. cereus spores and prevented biofilm formation at 12.5 μg/mL. Moreover, Lys14579 displayed good antimicrobial stability with negligible hemolysis in mouse red blood cells and no cytotoxicity against RAW264.7 cells. Notably, Lys14579 effectively inhibited B. cereus in boiled rice and minced meat in a dose-dependent manner. Furthermore, bioinformatics analysis and point mutagenesis experiments revealed that Glu-47 was the catalytic site, and Asp-57, Gln-60, Ser-61 and Glu-63 were active-site residues related with the cell wall lytic activity. Taken together, Lys14579 could be a promising biocontrol agent against vegetative cells, spores, and biofilm of B. cereus in food industry.}, } @article {pmid38335750, year = {2024}, author = {Liang, C and Wei, Z and Bester, K}, title = {Transformation mechanisms of the antidepressant citalopram in a moving bed biofilm reactor: Substrate-depended pathways, eco-toxicities and enantiomeric profiles.}, journal = {Water research}, volume = {252}, number = {}, pages = {121245}, doi = {10.1016/j.watres.2024.121245}, pmid = {38335750}, issn = {1879-2448}, abstract = {Citalopram (CIT) is one of the most consumed antidepressants and frequently detected in aquatic environments worldwide. Conventional wastewater treatment cannot remove this neuronal active pharmaceutical efficiently. Past studies showed that moving bed biofilm reactors (MBBRs) can degrade CIT but the exact transformation pathways and toxicity reduction remained unclear. In this study, the effects of substrate stimulation on CIT transformation in an MBBR were systematically investigated. The results showed that a co-metabolic stimulation by acetate increased the transformation rate by 54 % and 24 % at high (300 μg/L) and environmental concentration (1.8 μg/L) of CIT, respectively. Conversely, the complex substrates in raw wastewater reduced the reaction rates by 44 %, suggesting a competitive inhibition on the enzymatic sites. The substrate stimulation changed the enantiomeric fraction (EF) of CIT from racemic (EF=0.5) to 0.60 at the high CIT concentrations, while those at lower concentrations resulted in an EF of 0.33, indicating that probably different enantioselective enzymes degraded CIT at high concentrations than at low concentrations, i.e., the presence of 300 µg/L CIT was possibly sufficient to induce the synthesis of different enantioselective enzymes, than those originally present. Through non-target and target analysis, in total 19 transformation products (TPs) including 7 TPs that were hitherto not mentioned in the literature were identified. Among these were quaternary amines, alkenes and conjugate TPs. The major transformation pathways were a) nitrile hydrolysis (up to 43 %), b) amide hydrolysis, and c) N-oxidation. Dosing acetate up-regulated significantly the amide hydrolysis, N-oxidation and conjugation pathways but inhibited the N-demethylation and α-carbon hydroxylation pathways. The in-silico toxicity assessment of CIT and its TPs suggested the overall eco-toxic potential of TPs was reduced by MBBR. Furthermore, the degradation under carbon-limited (famine) conditions favored the formation of the more toxic carboxamide, N-desmethyl and alkene TPs, while carbon-rich conditions, promoted the production of the less toxic carboxylic acid, N-oxide and ester TPs. Therefore, this study demonstrated that a) the co-metabolic stimulation of CIT metabolization by dosing a simple carbon source or b) inhibition of CIT metabolization by complex substrates; c) substrate stimulation made a difference on CIT transformation rates, enantiomeric profiles, pathways and toxic potentials. Overall, a simple-carbon co-metabolic stimulated MBBR was an efficient up-regulation strategy to minimize hazardous CIT and CIT-TPs as much as possible.}, } @article {pmid38335452, year = {2024}, author = {Li, J and Zhao, X and Xia, Y and Qi, X and Jiang, C and Xiao, Y and Jiang, F and Jiang, X and Yuan, G}, title = {Strontium-Containing Piezoelectric Biofilm Promotes Dentin Tissue Regeneration.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2313419}, doi = {10.1002/adma.202313419}, pmid = {38335452}, issn = {1521-4095}, abstract = {It remains an obstacle to induce the regeneration of hard dentin tissue in clinical settings. To overcome this, a P(VDF-TrFE) piezoelectric film with 2wt% SrCl2 addition is designed. The biofilm shows a high flexibility, a harmonious biocompatibility, and a large piezoelectric d33 coefficient of 14 pC N[-1] , all contributing to building an electric microenvironment that favor the recruitment of dental pulp stem cells (DPSCs) and their differentiation into odontoblasts during normal chewing, speaking, etc. On the other hand, the strontium ions can be gradually released from the film, thus promoting DPSC odonto-differentiation. In vivo experiments also demonstrate that the film induces the release of dentin minerals and regeneration of dentin tissue. In the large animal dentin defect models, this piezoelectric film induces in situ dentin tissue formation effectively over a period of three months. This study illustrates a therapeutic potential of the piezoelectric film to improve dentin tissue repair in clinical settings. This article is protected by copyright. All rights reserved.}, } @article {pmid38333580, year = {2024}, author = {Blanco-Romero, E and Garrido-Sanz, D and Durán, D and Rybtke, M and Tolker-Nielsen, T and Redondo-Nieto, M and Rivilla, R and Martín, M}, title = {Role of extracellular matrix components in biofilm formation and adaptation of Pseudomonas ogarae F113 to the rhizosphere environment.}, journal = {Frontiers in microbiology}, volume = {15}, number = {}, pages = {1341728}, pmid = {38333580}, issn = {1664-302X}, abstract = {Regulating the transition of bacteria from motile to sessile lifestyles is crucial for their ability to compete effectively in the rhizosphere environment. Pseudomonas are known to rely on extracellular matrix (ECM) components for microcolony and biofilm formation, allowing them to adapt to a sessile lifestyle. Pseudomonas ogarae F113 possesses eight gene clusters responsible for the production of ECM components. These gene clusters are tightly regulated by AmrZ, a major transcriptional regulator that influences the cellular levels of c-di-GMP. The AmrZ-mediated transcriptional regulation of ECM components is primarily mediated by the signaling molecule c-di-GMP and the flagella master regulator FleQ. To investigate the functional role of these ECM components in P. ogarae F113, we performed phenotypic analyses using mutants in genes encoding these ECM components. These analyses included assessments of colony morphology, dye-staining, static attachment to abiotic surfaces, dynamic biofilm formation on abiotic surfaces, swimming motility, and competitive colonization assays of the rhizosphere. Our results revealed that alginate and PNAG polysaccharides, along with PsmE and the fimbrial low molecular weight protein/tight adherence (Flp/Tad) pilus, are the major ECM components contributing to biofilm formation. Additionally, we found that the majority of these components and MapA are needed for a competitive colonization of the rhizosphere in P. ogarae F113.}, } @article {pmid38332949, year = {2023}, author = {Zubair, M and Husain, FM and Al-Amri, M and Hasan, I and Hassan, I and Albalawi, T and Fatima, F and Khan, A and Arshad, M and Alam, P and Ahmad, N and Alatawy, R and Begum, S and Mir, R and Alshadfan, H and Ansari, AA and Al-Anazi, ABAA}, title = {In vitro inhibition of biofilm and virulence factor production in azole-resistant strains of Candida albicans isolated from diabetic foot by Artemisia vulgaris stabilized tin (IV) oxide nanoparticles.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1322778}, pmid = {38332949}, issn = {2235-2988}, abstract = {The advent of nanotechnology has been instrumental in the development of new drugs with novel targets. Recently, metallic nanoparticles have emerged as potential candidates to combat the threat of drug-resistant infections. Diabetic foot ulcers (DFUs) are one of the dreadful complications of diabetes mellitus due to the colonization of numerous drug-resistant pathogenic microbes leading to biofilm formation. Biofilms are difficult to treat due to limited penetration and non-specificity of drugs. Therefore, in the current investigation, SnO2 nanoparticles were biosynthesized using Artemisia vulgaris (AvTO-NPs) as a stabilizing agent and were characterized using ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the efficacy of AvTO-NPs against biofilms and virulence factors of drug-resistant Candida albicans strains isolated from DFUs was assessed. AvTO-NPs displayed minimum inhibitory concentrations (MICs) ranging from 1 mg/mL to 2 mg/mL against four strains of C. albicans. AvTO-NPs significantly inhibited biofilm formation by 54.8%-87%, germ tube formation by 72%-90%, cell surface hydrophobicity by 68.2%-82.8%, and exopolysaccharide (EPS) production by 69%-86.3% in the test strains at respective 1/2xMIC. Biosynthesized NPs were effective in disrupting established mature biofilms of test strains significantly. Elevated levels of reactive oxygen species (ROS) generation in the AvTO-NPs-treated C. albicans could be the possible cause of cell death leading to biofilm inhibition. The useful insights of the present study could be exploited in the current line of treatment to mitigate the threat of biofilm-related persistent DFUs and expedite wound healing.}, } @article {pmid38331692, year = {2024}, author = {Yang, ZR and Qin, H and Fan, JW and Du, K and Qi, L and Hou, D and Jiang, H and Zhu, J}, title = {Acidity-activated aggregation and accumulation of self-complementary zwitterionic peptide-decorated gold nanoparticles for photothermal biofilm eradication.}, journal = {Journal of colloid and interface science}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jcis.2024.02.018}, pmid = {38331692}, issn = {1095-7103}, abstract = {Drug-resistant biofilm infection is an extremely serious clinical problem, that easily leads to failure of antibiotic treatment. Although gold nanoparticles (AuNPs) as photothermal agents have been widely used in biofilm eradication, there are still challenges to be addressed, such as insignificantly redshifted absorption and slow assembly process of aggregated AuNPs. Herein, we developed an acidity-activated dispersion-to-aggregation transition to enhance the accumulation of self-complementary zwitterionic peptide-decorated AuNPs for photothermal eradication of drug-resistant biofilm infections. AuNPs were decorated with self-complementary zwitterionic peptides (ZP1 and ZP2) coupled with pH-sensitive anhydride (DMA) and pH-insensitive anhydride (SA), respectively. ZP2-decorated AuNPs with DMA modification (AuNP@ZP2(DMA)) exhibited prolonged blood circulation and enhanced accumulation in acidic biofilm microenvironment. Moreover, the electrostatic attraction between self-complementary ligands drove AuNPs to form closely packed aggregates with strong near-infrared absorption, leading to in vivo photoacoustic imaging ability and photothermal effect against drug-resistant bacteria and fungus, as well as microbial biofilms. AuNP@ZP2(DMA) with longer charge domains and a polyethylene glycol oligomer spacer showed greater photothermal antimicrobial and biofilm resistance in vitro and in vivo. This study develops an innovative acidity-activated AuNP photothermal agent, which provides an effective approach for treatment of biofilm infections.}, } @article {pmid38331378, year = {2024}, author = {He, W and Liu, H and Wang, Z and Tay, FR and Shen, Y}, title = {The Dynamics of Bacterial Proliferation, Viability, and Extracellular Polymeric Substances in Oral Biofilm Development.}, journal = {Journal of dentistry}, volume = {}, number = {}, pages = {104882}, doi = {10.1016/j.jdent.2024.104882}, pmid = {38331378}, issn = {1879-176X}, abstract = {OBJECTIVES: This study investigated the relationship between bacterial growth, viability, and extracellular polymeric substances (EPS) formation in biofilms, particularly regarding resistance development. It also examined the impact of chemical factors on the EPS matrix and bacterial proliferation in oral biofilms.

METHODS: Three multi-species oral biofilms were incubated in anaerobic conditions. Three strains of Enterococcus faecalis were incubated in aerobic conditions. The incubation periods ranged from 0 hours to 7 days for short-term biofilms, and from 3 to 90 days for long-term biofilms. Fluorescent labeling with carboxyfluorescein diacetate succinimidyl ester (CFSE) and flow cytometry were used to track EPS and bacterial growth. Confocal laser scanning microscopy (CLSM) assessed bacterial viability and EPS structure. Biofilms aged 7, 14, and 21 days were treated with 2% chlorhexidine (CHX) and 1% sodium hypochlorite (NaOCl) to evaluate their effects on EPS and bacterial proliferation.

RESULTS: Short-term biofilms showed rapid bacterial proliferation and a gradual increase in EPS, maintaining stable viability. In the first two weeks, a significant rise in CFSE indicated growing maturity. From 14 to 90 days, EPS and CFSE levels stabilized. Following treatment, CHX significantly reduced bacterial proliferation, while NaOCl decreased EPS volume.

CONCLUSIONS: Biofilm development involves a balance between bacterial proliferation and EPS production. The complexity of this process poses challenges in treating biofilm-associated infections, requiring strategies tailored to the biofilm's developmental stage.

CLINICAL SIGNIFICANCE: For effective root canal treatment, it is imperative to focus on reducing bacterial proliferation during the early stages of oral infections. In contrast, strategies aimed at minimizing EPS production could be more beneficial for long-term management of these conditions.}, } @article {pmid38329985, year = {2024}, author = {Ma, H and Alt, DP and Falkenberg, SM and Briggs, RE and Tatum, FM and Clawson, ML and Casas, E and Dassanayake, RP}, title = {Transcriptomic profiles of Mannheimia haemolytica planktonic and biofilm associated cells.}, journal = {PloS one}, volume = {19}, number = {2}, pages = {e0297692}, doi = {10.1371/journal.pone.0297692}, pmid = {38329985}, issn = {1932-6203}, abstract = {Mannheimia haemolytica is the principal agent contributing to bovine respiratory disease and can form biofilms with increased resistance to antibiotic treatment and host immune defenses. To investigate the molecular mechanisms underlying M. haemolytica biofilm formation, transcriptomic analyses were performed with mRNAs sequenced from planktonic and biofilm cultures of pathogenic serotypes 1 (St 1; strain D153) and St 6 (strain D174), and St 2 (strain D35). The three M. haemolytica serotypes were cultured in two different media, Roswell Park Memorial Institute (RPMI) 1640 and brain heart infusion (BHI) to form the biofilms. Transcriptomic analyses revealed that the functions of the differentially expressed genes (DEGs) in biofilm associated cells were not significantly affected by the two media. A total of 476 to 662 DEGs were identified between biofilm associated cells and planktonic cells cultured under BHI medium. Functional analysis of the DEGs indicated that those genes were significantly enriched in translation and many biosynthetic processes. There were 234 DEGs identified in St 1 and 6, but not in St 2. The functions of the DEGs included structural constituents of ribosomes, transmembrane proton transportation, proton channels, and proton-transporting ATP synthase. Potentially, some of the DEGs identified in this study provide insight into the design of new M. haemolytica vaccine candidates.}, } @article {pmid38329365, year = {2024}, author = {Zhao, R and Du, B and Luo, Y and Xue, F and Wang, H and Qu, D and Han, S and Heilbronner, S and Zhao, Y}, title = {Antimicrobial and anti-biofilm activity of a thiazolidinone derivative against Staphylococcus aureus in vitro and in vivo.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0232723}, doi = {10.1128/spectrum.02327-23}, pmid = {38329365}, issn = {2165-0497}, abstract = {Staphylococcus aureus (S. aureus) causes many infections with significant morbidity and mortality. S. aureus can form biofilms, which can cause biofilm-associated diseases and increase resistance to many conventional antibiotics, resulting in chronic infection. It is critical to develop novel antibiotics against staphylococcal infections, particularly those that can kill cells embedded in biofilms. This study aimed to investigate the bacteriocidal and anti-biofilm activities of thiazolidinone derivative (TD-H2-A) against S. aureus. A total of 40 non-duplicate strains were collected, and the minimum inhibitory concentrations (MICs) of TD-H2-A were determined. The effect of TD-H2-A on established S. aureus mature biofilms was examined using a confocal laser scanning microscope (CLSM). The antibacterial effects of the compound on planktonic bacteria and bacteria in mature biofilms were investigated. Other characteristics, such as cytotoxicity and hemolytic activity, were researched. A mouse skin infection model was used, and a routine hematoxylin and eosin (H&E) staining was used for histological examination. The MIC values of TD-H2-A against the different S. aureus strains were 6.3-25.0 µg/mL. The 5 × MIC TD-H2-A killed almost all planktonic S. aureus USA300. The derivative was found to have strong bacteriocidal activity against cells in mature biofilms meanwhile having low cytotoxicity and hemolytic activity against Vero cells and human erythrocytes. TD-H2-A had a good bacteriocidal effect on S. aureus SA113-infected mice. In conclusion, TD-H2-A demonstrated good bacteriocidal and anti-biofilm activities against S. aureus, paving the way for the development of novel agents to combat biofilm infections and multidrug-resistant staphylococcal infections.IMPORTANCEStaphylococcus aureus, a notorious pathogen, can form a stubborn biofilm and develop drug resistance. It is crucial to develop new anti-infective therapies against biofilm-associated infections. The manuscript describes the new antibiotic to effectively combat multidrug-resistant and biofilm-associated diseases.}, } @article {pmid38328888, year = {2024}, author = {Özmen, P and Erdoğan, H and Güngördü, A and Pişkin, B and Çobankara, FK and Sütcü, S and Şahin, N}, title = {Comparison of antimicrobial efficacy of different disinfectants on the biofilm formation in dental unit water systems using dip slide and conventional methods: A pilot study.}, journal = {Microscopy research and technique}, volume = {}, number = {}, pages = {}, doi = {10.1002/jemt.24511}, pmid = {38328888}, issn = {1097-0029}, support = {//Kapadokya Üniversitesi/ ; }, abstract = {OBJECTIVE: Biofilm formation in dental waterlines brings opportunistic infections, especially for immunosuppressive patients. This study aimed to determine biofilm-forming microorganisms by various methods and investigate disinfectants' effects on biofilm.

MATERIALS & METHODS: In the study, samples were obtained from the waterlines of 10-15 aged six dental units, before (0 min.) and after chlorine dioxide (ClO2) and hypochlorous acid (HOCl) treatment (1, 5, 10, 20, and 30 min.), and total colony counts were performed using conventional surface smear method (SSM) and dip slide method (DSM). The Congo red agar and Christensen methods were used to examine the biofilm-forming properties of the isolates. Monitoring of biofilm presence was also visualized by SEM scanning.

RESULTS: When DSM and SSM are compared in all units where ClO2 and HOCl are applied, DSM can detect bacterial growth even during periods of greater exposure to disinfectant application. Although DSM can achieve a value approaching 3% even at the 10th minute in units treated with HOCl; SSM does not show reproduction at the same disinfectant exposure and duration; It was observed that in the units where ClO2 was applied, the growth was no longer observed at the 10th minute with DSM, and SSM, 50% growth in the first minute of the units treated with ClO2 could not be detected in the 5th minute.

CONCLUSIONS: It is concluded that it can be advisable to routinely disinfect the dental unit water systems with non-toxic doses of ClO2 application before patient treatments in clinics and also to perform contamination controls at regular intervals with DSM, which is a sensitive and very practical method.

RESEARCH HIGHLIGHTS: It has been observed that the dip slide method can count bacteria more sensitively than conventional methods in dental water systems without the need for experienced personnel and equipment. The difference between biofilm formation in water systems before and after disinfectant exposure in SEM examinations is remarkable. The effects of ClO2 and HOCl on biofilm were investigated and bacterial growth was inhibited in dental units between 5 and 10 minutes with both disinfectants.}, } @article {pmid38328073, year = {2024}, author = {Hall, JM and Gutiérrez-Ferman, JL and Shamseldin, MM and Guo, M and Gupta, YA and Deora, R and Dubey, P}, title = {Opposing effects of acellular and whole cell pertussis vaccines on Bordetella pertussis biofilm formation, Siglec-F+ neutrophil recruitment and bacterial clearance in mouse nasal tissues.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2024.01.23.576795}, pmid = {38328073}, abstract = {UNLABELLED: Despite global vaccination, pertussis caused by Bordetella pertussis (Bp) is resurging. Pertussis resurgence is correlated with the switch from whole cell vaccines (wPV) that elicit T H 1/T H 17 polarized immune responses to acellular pertussis vaccines (aPV) that elicit primarily T H 2 polarized immune responses. One explanation for the increased incidence in aPV-immunized individuals is the lack of bacterial clearance from the nose. To understand the host and bacterial mechanisms that contribute to Bp persistence, we evaluated bacterial localization and the immune response in the nasal associated tissues (NT) of naïve and immunized mice following Bp challenge. Bp resided in the NT of unimmunized and aPV-immunized mice as biofilms. In contrast, Bp biofilms were not observed in wPV-immunized mice. Following infection, Siglec-F+ neutrophils, critical for eliminating Bp from the nose, were recruited to the nose at higher levels in wPV immunized mice compared to aPV immunized mice. Consistent with this observation, the neutrophil chemokine CXCL1 was only detected in the NT of wPV immunized mice. Importantly, the bacteria and immune cells were primarily localized within the NT and were not recovered by nasal lavage (NL). Together, our data suggest that the T H 2 polarized immune response generated by aPV vaccination facilitates persistence in the NT by impeding the infiltration of immune effectors and the eradication of biofilms In contrast, the T H 1/T H 17 immune phenotype generated by wPV, recruits Siglec-F+ neutrophils that rapidly eliminate the bacterial burden and prevent biofilm establishment. Thus, our work shows that aPV and wPV have opposing effects on Bp biofilm formation in the respiratory tract and provides a mechanistic explanation for the inability of aPV vaccination to control bacterial numbers in the nose and prevent transmission.

AUTHOR SUMMARY: Acellular pertussis vaccine (aPV) immunized individuals maintain a nasal reservoir of Bordetella pertussis (Bp) and thus have the potential to transmit the infection to vulnerable individuals. Here we provide a mechanistic explanation for the inability of aPV to eliminate Bp from the nasal cavity. We show that following bacterial challenge of aPV immunized mice, Siglec-F+ neutrophils and other immune effectors are not recruited to the nose. Consequently, Bp remain in the nose and form biofilms. In contrast, whole cell pertussis (wPV) immunized mice produce immune effectors following bacterial challenge that recruit Siglec-F+ neutrophils to the nose. Bp burden is cleared from the nasal tissues, thereby preventing bacterial persistence and the formation of biofilms.}, } @article {pmid38326515, year = {2024}, author = {Aboelenin, AM and El-Mowafy, M and Saleh, NM and Shaaban, MI and Barwa, R}, title = {Ciprofloxacin- and levofloxacin-loaded nanoparticles efficiently suppressed fluoroquinolone resistance and biofilm formation in Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {3125}, pmid = {38326515}, issn = {2045-2322}, abstract = {The spread of fluoroquinolone (FQ) resistance in Acinetobacter baumannii represents a critical health threat. This study aims to overcome FQ resistance in A. baumannii via the formulation of polymeric nanoFQs. Herein, 80 A. baumannii isolates were obtained from diverse clinical sources. All A. baumannii isolates showed high resistance to most of the investigated antimicrobials, including ciprofloxacin (CIP) and levofloxacin (LEV) (97.5%). FQ resistance-determining regions of the gyrA and parC genes were the most predominant resistant mechanism, harbored by 69 (86.3%) and 75 (93.8%) of the isolates, respectively. Additionally, plasmid-mediated quinolone resistance genes aac(6')-Ib and qnrS were detected in 61 (76.3%) and 2 (2.5%) of the 80 isolates, respectively. The CIP- and LEV-loaded poly ε-caprolactone (PCL) nanoparticles, FCIP and FLEV, respectively, showed a 1.5-6- and 6-12-fold decrease in the MIC, respectively, against the tested isolates. Interestingly, the time kill assay demonstrated that MICs of FCIP and FLEV completely killed A. baumannii isolates after 5-6 h of treatment. Furthermore, FCIP and FLEV were found to be efficient in overcoming the FQ resistance mediated by the efflux pumps in A. baumannii isolates as revealed by decreasing the MIC four-fold lower than that of free CIP and LEV, respectively. Moreover, FCIP and FLEV at 1/2 and 1/4 MIC significantly decreased biofilm formation by 47-93% and 69-91%, respectively. These findings suggest that polymeric nanoparticles can restore the effectiveness of FQs and represent a paradigm shift in the fight against A. baumannii isolates.}, } @article {pmid38324986, year = {2024}, author = {Wang, M and Sun, H and Ma, X and Wang, H and Shi, B}, title = {Metabolic response of bacterial community to sodium hypochlorite and ammonia nitrogen affected the antibiotic resistance genes in pipelines biofilm.}, journal = {Water research}, volume = {252}, number = {}, pages = {121179}, doi = {10.1016/j.watres.2024.121179}, pmid = {38324986}, issn = {1879-2448}, abstract = {The biofilm is important for the antibiotic resistance genes (ARGs) propagation in drinking water pipelines. This study investigated the influence of chlorine disinfection and ammonia nitrogen on the ARGs in pipelines biofilm using metagenomic and metabolomics analysis. Chlorine disinfection reduced the relative abundance of unclassified_c_Actinobacteria, Acidimicrobium, and Candidatus_Pelagibacter to 394-430 TPM, 114-123 TPM, and 49-54 TPM, respectively. Correspondingly, the ARGs Saur_rpoC_DAP, macB, and mfd was reduced to 8-12 TPM, 81-92 TPM and 30-35 TPM, respectively. The results of metabolomics suggested that chlorine disinfection suppressed the pathways of ABC transporters, fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, and biosynthesis of amino acids. These pathways were related to the cell membrane integrality and extracellular polymeric substances (EPS) secretion. Chlorine disinfection induced the decrease of EPS-related genes, resulting in the lower relative abundance of bacterial community and their antibiotic resistance. However, added approximately 0.5 mg/L NH3-N induced up-regulation of these metabolic pathways. In addition, NH3-N addition increased the relative abundance of enzymes related to inorganic and organic nitrogen metabolic pathway significantly, such as ammonia monooxygenase, glutamine synthetase, and glutamate synthase. Due to the EPS protection and nitrogen metabolism, the relative abundance of the main bacterial genera and the related ARGs increased to the level equal to that in pipelines biofilm with no disinfection. Therefore, NH3-N reduced the ARGs removal efficiency of chlorine disinfection. It is necessary to take measures to improve the removal rate of NH3-N and ARGs for preventing their risks in drinking water.}, } @article {pmid38324331, year = {2024}, author = {Mayorga-Martinez, CC and Zhang, L and Pumera, M}, title = {Chemical multiscale robotics for bacterial biofilm treatment.}, journal = {Chemical Society reviews}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3cs00564j}, pmid = {38324331}, issn = {1460-4744}, abstract = {A biofilm constitutes a bacterial community encased in a sticky matrix of extracellular polymeric substances. These intricate microbial communities adhere to various host surfaces such as hard and soft tissues as well as indwelling medical devices. These microbial aggregates form a robust matrix of extracellular polymeric substances (EPSs), leading to the majority of human infections. Such infections tend to exhibit high resistance to treatment, often progressing into chronic states. The matrix of EPS protects bacteria from a hostile environment and prevents the penetration of antibacterial agents. Modern robots at nano, micro, and millimeter scales are highly attractive candidates for biomedical applications due to their diverse functionalities, such as navigating in confined spaces and targeted multitasking. In this tutorial review, we describe key milestones in the strategies developed for the removal and eradication of biofilms using robots of different sizes and shapes. It can be seen that robots at different scales are useful and effective tools for treating bacterial biofilms, thus preventing persistent infections, the loss of costly implanted medical devices, and additional costs associated with hospitalization and therapies.}, } @article {pmid38322580, year = {2024}, author = {Calvanese, M and D'Angelo, C and Lauro, C and Tutino, ML and Parrilli, E}, title = {Recombinant protein production in Pseudoalteromonas haloplanktis TAC125 biofilm.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100179}, doi = {10.1016/j.bioflm.2024.100179}, pmid = {38322580}, issn = {2590-2075}, abstract = {Biofilms have great potential for producing valuable products, and recent research has been performed on biofilms for the production of compounds with biotechnological and industrial relevance. However, the production of recombinant proteins using this system is still limited. The recombinant protein production in microbial hosts is a well-established technology and a variety of expression systems are available. Nevertheless, the production of some recombinant proteins can result in proteolyzed, insoluble, and non-functional forms, therefore it is necessary to start the exploration of non-conventional production systems that, in the future, could be helpful to produce some "difficult" proteins. Non-conventional production systems can be based on the use of alternative hosts and/or on non-conventional ways to grow recombinant cells. In this paper, the use of the Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 grown in biofilm conditions was explored to produce two fluorescent proteins, GFP and mScarlet. The best conditions for the production were identified by working on media composition, and induction conditions, and by building a new expression vector suitable for the biofilm conditions. Results reported demonstrated that the optimized system for the recombinant protein production in biofilm, although it takes longer than planktonic production, has the same potentiality as the classical planktonic approach with additional advantages since it needs a lower concentration of the carbon sources and doesn't require antibiotic addition. Moreover, in the case of mScarlet, the production in biofilm outperforms the planktonic system in terms of a better quality of the recombinant product.}, } @article {pmid38322579, year = {2024}, author = {Mahadevaswamy, UR and Mugunthan, S and Seviour, T and Kjelleberg, S and Lim, S}, title = {Evaluating a polymicrobial biofilm model for structural components by co-culturing Komagataeibacter hansenii produced bacterial cellulose with Pseudomonas aeruginosa PAO1.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100176}, doi = {10.1016/j.bioflm.2024.100176}, pmid = {38322579}, issn = {2590-2075}, abstract = {A polymicrobial biofilm model of Komagataeibacter hansenii and Pseudomonas aeruginosa was developed to understand whether a pre-existing matrix affects the ability of another species to build a biofilm. P. aeruginosa was inoculated onto the preformed K. hansenii biofilm consisting of a cellulose matrix. P. aeruginosa PAO1 colonized and infiltrated the K. hansenii bacterial cellulose biofilm (BC), as indicated by the presence of cells at 19 μm depth in the translucent hydrogel matrix. Bacterial cell density increased along the imaged depth of the biofilm (17-19 μm). On day 5, the average bacterial count across sections was 67 ± 4 % P. aeruginosa PAO1 and 33 ± 6 % K. hansenii. Biophysical characterization of the biofilm indicated that colonization by P. aeruginosa modified the biophysical properties of the BC matrix, which inlcuded increased density, heterogeneity, degradation temperature and thermal stability, and reduced crystallinity, swelling ability and moisture content. This further indicates colonization of the biofilm by P. aeruginosa. While eDNA fibres - a key viscoelastic component of P. aeruginosa biofilm - were present on the surface of the co-cultured biofilm on day 1, their abundance decreased over time, and by day 5, no eDNA was observed, either on the surface or within the matrix. P. aeruginosa-colonized biofilm devoid of eDNA retained its mechanical properties. The observations demonstrate that a pre-existing biofilm scaffold of K. hansenii inhibits P. aeruginosa PAO1 eDNA production and suggest that eDNA production is a response by P. aeruginosa to the viscoelastic properties of its environment.}, } @article {pmid38321959, year = {2024}, author = {Sharma, V and Gogoi, B and Borah, SN and Ghosh, A and Mazumdar, A and Kalita, RD}, title = {In-silico molecular docking and molecular dynamic simulation of γ-elemene and caryophyllene identified from the essential oil of Kaempferia galanga L. against biofilm forming proteins, CrtM and SarA of Staphylococcus aureus.}, journal = {Journal of biomolecular structure & dynamics}, volume = {}, number = {}, pages = {1-13}, doi = {10.1080/07391102.2024.2310773}, pmid = {38321959}, issn = {1538-0254}, abstract = {Medicinal plants play an important role as antimicrobials by inhibiting various key targets of diverse microorganisms. A major antimicrobial component of plants is its essential oil, which are increasingly being studied for their antimicrobial properties as well as for their potential role in the inhibition of biofilm formation. In the present study, essential oil from Kaempferia galanga L was isolated resulting in the identification of eleven compounds. Of these, two of the compounds, γ-elemene and caryophyllene were found to dock with the target proteins, CrtM and SarA of Staphylococcus aureus, which are essential for the formation of biofilm. γ-elemene demonstrated the best binding affinity with CrtM with binding energy of -8.1 kcal/mol whereas caryophyllene and its derivative isocaryophyllene showed the best binding with SarA with binding energy -6.1 kcal/mol. ADMET study of the compounds also revealed that the compounds are non-toxic and can be used as probable compounds for inhibition of biofilms. Molecular dynamic simulation studies revealed high affinity of binding and stability of the molecules with their targets. PCA analysis helped in identifying the principal motions occurring within a trajectory that are essential in inducing conformational changes.Communicated by Ramaswamy H. Sarma.}, } @article {pmid38320965, year = {2024}, author = {Sun, W and Sun, J and Ding, Q and Qi, M and Zhou, J and Shi, Y and Liu, J and Won, M and Sun, X and Bai, X and Dong, B and Kim, JS and Wang, L}, title = {Breaking Iron Homeostasis: Iron Capturing Nanocomposites for Combating Bacterial Biofilm.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {}, number = {}, pages = {e202319690}, doi = {10.1002/anie.202319690}, pmid = {38320965}, issn = {1521-3773}, abstract = {Given the scarcity of novel antibiotics, the eradication of bacterial biofilm infections poses formidable challenges. Upon bacterial infection, the host restricts Fe ions, which are crucial for bacterial growth and maintenance. Having coevolved with the host, bacteria developed adaptive pathways like the hemin-uptake system to avoid iron deficiency. Inspired by this, we propose a novel strategy, termed iron nutritional immunity therapy (INIT), utilizing Ga-CT@P nanocomposites constructed with gallium, copper-doped tetrakis (4-carboxyphenyl) porphyrin (TCPP) metal-organic framework, and polyamine-amine polymer dots, to target bacterial iron intakes and starve them. Owing to the similarity between iron/hemin and gallium/TCPP, gallium-incorporated porphyrin potentially deceives bacteria into uptaking gallium ions and concurrently extracts iron ions from the surrounding bacteria milieu through the porphyrin ring. This strategy orchestrates a "give and take" approach for Ga3+/Fe3+ exchange. Simultaneously, polymer dots can impede bacterial iron metabolism and serve as real-time fluorescent iron-sensing probes to continuously monitor dynamic iron restriction status. INIT based on Ga-CT@P nanocomposites induced long-term iron starvation, which affected iron-sulfur cluster biogenesis and carbohydrate metabolism, ultimately facilitating biofilm eradication and tissue regeneration. Therefore, this study presents an innovative antibacterial strategy from a nutritional perspective that sheds light on refractory bacterial infection treatment and its future clinical application.}, } @article {pmid38320641, year = {2024}, author = {Patel, M and Kikani, T and Saren, U and Thakore, S}, title = {Bactericidal, anti-biofilm, anti-oxidant potency and catalytic property of silver nanoparticles embedded into functionalised chitosan gel.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {129968}, doi = {10.1016/j.ijbiomac.2024.129968}, pmid = {38320641}, issn = {1879-0003}, abstract = {Chitosan is a versatile biocompatible polysaccharide which has attracted great attention for gel synthesis. Its reducing character is specifically exploited for nanoparticle synthesis via green approach. A silver nanocomposite synthesized using this gel, with a novel gelling agent 2,4,6-trihydroxy benzaldehyde, was found to be a promising candidate for several applications including anti-bacterial, anti-biofilm and anti-oxidant activity as well as catalysis. The nanocomposite was well characterized using various spectroscopic and microscopic techniques such as IR, TGA, XRD, XPS, SEM and TEM. The nanocomposite exhibited high bactericidal activity against both S. aureus and E. coli. Further, it was evaluated for anti-biofilm forming property and its potency as antioxidant agent. The nanocomposite served as a catalyst for degradation of Methyl Orange and Rhodamine B at high concentrations (in the range of mM) with a catalytic efficiency of 98.58 % and 99.56 % within 3 min and 5 min respectively.}, } @article {pmid38319530, year = {2024}, author = {Zanzan, M and Ezzaky, Y and Hamadi, F and Achemchem, F}, title = {Enterococcus mundtii A2 biofilm and its anti-adherence potential against pathogenic microorganisms on stainless steel 316L.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {38319530}, issn = {1678-4405}, abstract = {Pathogenic bacterial biofilms present significant challenges, particularly in food safety and material deterioration. Therefore, using Enterococcus mundtii A2, known for its antagonistic activity against pathogen adhesion, could serve as a novel strategy to reduce pathogenic colonization within the food sector. This study aimed to investigate the biofilm-forming ability of E. mundtii A2, isolated from camel milk, on two widely used stainless steels within the agri-food domain and to assess its anti-adhesive properties against various pathogens, especially on stainless steel 316L. Additionally, investigations into auto-aggregation and co-aggregation were also conducted. Plate count methodologies revealed increased biofilm formation by E. mundtii A2 on 316L, followed by 304L. Scanning electron microscopy (SEM) analysis revealed a dense yet thin biofilm layer, playing a critical role in reducing the adhesion of L. monocytogenes CECT 4032 and Staphylococcus aureus CECT 976, with a significant reduction of ≈ 2 Log CFU/cm[2]. However, Gram-negative strains, P. aeruginosa ATCC 27853 and E. coli ATCC 25922, exhibit modest adhesion reduction (~ 0.7 Log CFU/cm[2]). The findings demonstrate the potential of applying E. mundtii A2 biofilms as an effective strategy to reduce the adhesion and propagation of potentially pathogenic bacterial species on stainless steel 316L.}, } @article {pmid38319113, year = {2024}, author = {Choi, A and Dong, K and Williams, E and Pia, L and Batagower, J and Bending, P and Shin, I and Peters, DI and Kaspar, JR}, title = {Human saliva modifies growth, biofilm architecture, and competitive behaviors of oral streptococci.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0077123}, doi = {10.1128/msphere.00771-23}, pmid = {38319113}, issn = {2379-5042}, abstract = {The bacteria within supragingival biofilms participate in complex exchanges with other microbes inhabiting the same niche. One example is the mutans group streptococci (Streptococcus mutans), implicated in the development of tooth decay, and other health-associated commensal streptococci species. Previously, our group transcriptomically characterized intermicrobial interactions between S. mutans and several species of oral bacteria. However, these experiments were carried out in a medium without human saliva. To better mimic their natural environment, we first evaluated how inclusion of saliva affected growth and biofilm formation of eight Streptococcus species individually and found saliva to positively benefit growth rates while negatively influencing biofilm biomass accumulation and altering spatial arrangement. These results carried over during evaluation of 29 saliva-derived isolates of various species. Surprisingly, we also found that addition of saliva increased the competitive behaviors of S. mutans in coculture competitions against commensal streptococci that led to increases in biofilm microcolony volumes. Through transcriptomically characterizing mono- and cocultures of S. mutans and Streptococcus oralis with and without saliva, we determined that each species developed a nutritional niche under mixed-species growth, with S. mutans upregulating carbohydrate uptake and utilization pathways while S. oralis upregulated genome features related to peptide uptake and glycan foraging. S. mutans also upregulated genes involved in oxidative stress tolerance, particularly manganese uptake, which we could artificially manipulate by supplementing in manganese leading to an advantage over its opponent. Our report highlights observable changes in microbial behaviors through leveraging environmental- and host-supplied resources over their competitors.IMPORTANCEDental caries (tooth decay) is the most prevalent disease for both children and adults nationwide. Caries are initiated from demineralization of the enamel due to organic acid production through the metabolic activity of oral bacteria growing in biofilm communities attached to the tooth's surface. Mutans group streptococci are closely associated with caries development and initiation of the cariogenic cycle, which decreases the amount of acid-sensitive, health-associated commensal bacteria while selecting for aciduric and acidogenic species that then further drives the disease process. Defining the exchanges that occur between mutans group streptococci and oral commensals in a condition that closely mimics their natural environment is of critical need toward identifying factors that can influence odontopathogen establishment, persistence, and outgrowth. The goal of our research is to develop strategies, potentially through manipulation of microbial interactions characterized here, that prevent the emergence of mutans group streptococci while keeping the protective flora intact.}, } @article {pmid38318096, year = {2024}, author = {Gebreyohannes, G and Sbhatu, DB and Nyerere, AK and Gebrehiwot, AG}, title = {Biofilm-Inhibitory Activity of Wild Mushroom Extracts against Pathogenic Bacteria.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2024}, number = {}, pages = {7011982}, doi = {10.1155/2024/7011982}, pmid = {38318096}, issn = {1741-427X}, abstract = {OBJECTIVE: This study aims to investigate the bacterial biofilm-inhibitory effect of mushroom extracts.

METHODS: Mushrooms were collected from Arabuko-Sokoke and Kakamega forests and identified using morphological and molecular approaches. Auricularia auricula-judae, Microporus xanthopus, Termitomyces umkowaani, Trametes elegans, and Trametes versicolor were extracted by chloroform, 70% ethanol, and hot water. Extracts were tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus (ATCC25923). Data were analyzed using SPSS ver. 20.0.

RESULTS: Chloroform, 70% ethanol, and hot water extracts of A. auricula-judae (50 μg/mL) showed statistically significant antibiofilm activities against P. aeruginosa, E. coli, and S. aureus (p ≤ 0.05). M. xanthopus extracts (250 μg/mL) revealed significantly significant antibiofilm activities against each test bacterium (p ≤ 0.05). All extracts of T. umkowaani (250 μg/mL) exhibited statistically significant antibiofilm activities against S. aureus only (p ≤ 0.05). Chloroform extract of T. elegans (250 μg/mL) showed the best antibiofilm activity (69.75 ± 0.01%) against S. aureus. All T. versicolor extracts (250 μg/mL) indicated the best antibiofilm activities against S. aureus.

CONCLUSIONS: Being the first study of its kind to be conducted in Kenya, it added a novel concept to the body of knowledge already known about medical biotechnology research. It offers a fresh understanding of the various varieties of mushrooms found in Kenya, their potential biological function in the production of drugs, particularly those that combat drug resistance, and perhaps even a peek at their bioactive elements. Wild mushrooms, a hidden gem, might help to reopen the pipeline of new antibiotics that have been on the decline. However, further research is required to determine the potential mechanism(s) of action of the extracts that are in charge of the apparent antibiofilm activity.}, } @article {pmid38317668, year = {2024}, author = {Asensio-López, J and Lázaro-Díez, M and Hernández-Cruz, TM and Blanco-Cabra, N and Sorzabal-Bellido, I and Arroyo-Urea, EM and Buetas, E and González-Paredes, A and Ortiz de Solórzano, C and Burgui, S and Torrents, E and Monteserín, M and Garmendia, J}, title = {Multimodal evaluation of drug antibacterial activity reveals cinnamaldehyde analog anti-biofilm effects against Haemophilus influenzae.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100178}, doi = {10.1016/j.bioflm.2024.100178}, pmid = {38317668}, issn = {2590-2075}, abstract = {Biofilm formation by the pathobiont Haemophilus influenzae is associated with human nasopharynx colonization, otitis media in children, and chronic respiratory infections in adults suffering from chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD). β-lactam and quinolone antibiotics are commonly used to treat these infections. However, considering the resistance of biofilm-resident bacteria to antibiotic-mediated killing, the use of antibiotics may be insufficient and require being replaced or complemented with novel strategies. Moreover, unlike the standard minimal inhibitory concentration assay used to assess antibacterial activity against planktonic cells, standardization of methods to evaluate anti-biofilm drug activity is limited. In this work, we detail a panel of protocols for systematic analysis of drug antimicrobial effect on bacterial biofilms, customized to evaluate drug effects against H. influenzae biofilms. Testing of two cinnamaldehyde analogs, (E)-trans-2-nonenal and (E)-3-decen-2-one, demonstrated their effectiveness in both H. influenzae inhibition of biofilm formation and eradication or preformed biofilms. Assay complementarity allowed quantifying the dynamics and extent of the inhibitory effects, also observed for ampicillin resistant clinical strains forming biofilms refractory to this antibiotic. Moreover, cinnamaldehyde analog encapsulation into poly(lactic-co-glycolic acid) (PLGA) polymeric nanoparticles allowed drug vehiculization while maintaining efficacy. Overall, we demonstrate the usefulness of cinnamaldehyde analogs against H. influenzae biofilms, present a test panel that can be easily adapted to a wide range of pathogens and drugs, and highlight the benefits of drug nanoencapsulation towards safe controlled release.}, } @article {pmid38317394, year = {2023}, author = {Peter, M and Kanathila, H and Bembalagi, M and Santhosh, VN and Vas, R and Patil, S and Roy, TR and Monsy, M and Gopu, BN and Chindak, S}, title = {An In Vitro Comparative Evaluation of Conventional and Novel Thymus vulgaris Derived Herbal Disinfectant Solutions against Pathogenic Biofilm on Maxillofacial Silicones and Its Impact on Color Stability.}, journal = {The journal of contemporary dental practice}, volume = {24}, number = {12}, pages = {967-973}, doi = {10.5005/jp-journals-10024-3602}, pmid = {38317394}, issn = {1526-3711}, abstract = {AIM: This study aims to assess the antimicrobial efficacy and impact on color stability of Thymus (T.) vulgaris solution compared to conventional disinfectants on maxillofacial silicones.

MATERIALS AND METHODS: Various solutions were evaluated, including T. vulgaris solutions at 5 and 10%, saline (control), chlorhexidine (4%), and soap water. The substrates were MDX4-4210 silicone elastomers, and the microorganisms tested were Candida (C.) albicans and Staphylococcus (S.) aureus. The viability of microorganisms was determined through an 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) reduction assay, and color stability was measured using a spectrophotometer with X-Rite Europe software. Statistical analysis was performed using the Kruskal-Wallis test, Mann-Whitney U post hoc test, and Wilcoxon Signed Rank test.

RESULTS: Soap water demonstrated superior disinfectant action against both microorganisms, while T. vulgaris solutions at 5 and 10% exhibited comparable antimicrobial efficacy. Chlorhexidine and 10% T. vulgaris solution showed minimal color changes in the silicone material. In contrast, soap water and the 5% T. vulgaris solution resulted in clinically unacceptable color alterations.

CONCLUSION: This study underscores the potential of T. vulgaris as an herbal disinfectant for combating microbial biofilms on maxillofacial silicones, particularly at concentrations of 5 and 10%. The importance of maintaining color stability is emphasized, with Chlorhexidine and the 10% T. vulgaris solution demonstrating effective preservation of esthetics. These findings suggest the viability of considering T. vulgaris as an alternative disinfectant in clinical settings for maxillofacial silicone prostheses.

CLINICAL SIGNIFICANCE: Maxillofacial silicones are vital in restoring aesthetic features for individuals with facial trauma, congenital deformities, or post-surgical interventions. Yet, biofilm-related infections jeopardize their durability and visual integrity. Clinically, T. vulgaris signifies a potential advance in prosthodontic care, offering valuable insights for improving antimicrobial performance and aesthetic durability in maxillofacial prostheses. How to cite this article: Peter M, Kanathila H, Bembalagi M, et al. An In Vitro Comparative Evaluation of Conventional and Novel Thymus vulgaris Derived Herbal Disinfectant Solutions against Pathogenic Biofilm on Maxillofacial Silicones and Its Impact on Color Stability. J Contemp Dent Pract 2023;24(12):967-973.}, } @article {pmid38317375, year = {2024}, author = {Nicola, D and Isabella, R and Carolina, C and Baldini, N and Raffaele, M}, title = {Treatment of peri-implant mucositis: Adjunctive effect of glycine powder air polishing to professional mechanical biofilm removal. 12 months randomized clinical study.}, journal = {Clinical implant dentistry and related research}, volume = {}, number = {}, pages = {}, doi = {10.1111/cid.13304}, pmid = {38317375}, issn = {1708-8208}, abstract = {INTRODUCTION: To evaluate the adjunctive effect of glycine-powder air-polishing (GPAP) to full-mouth ultrasonic debridement (Fm-UD) in the treatment of peri-implant mucositis, and to determine the impact of implant and patient-level variables for disease resolution.

METHODS: Individuals with a diagnosis of peri-implant mucositis were consecutively included in this randomized parallel arm clinical study. All the participants received a session of Fm-UD. Only implants allocated to the test group were additionally treated with GPAP. Clinical assessments were recorded at baseline, at 3 and at 12 months following intervention. The primary outcomes were complete disease resolution (DR1), defined as absence of bleeding sites at probing per implants, and partial disease resolution (DR2), measured as the presence of less than two bleeding sites at probing per implant. A final logistic multivariate regression model was built to evaluate the predictive role of implant and patient-level variables on DR.

RESULTS: Fifty two patients and 157 implants were included. Both groups displayed significant reduction in the extent of bleeding on probing and plaque levels. At 12 months, DR1 was achieved in 16% and 27% of participants for the test and the control group respectively. IDR1 was best predicted by the number of bleeding sites (OR = 2.7, p = 0.04) and the greatest PPD value (OR = 2.7, p = 0.05), while IDR2 by the prosthetic connection (OR = 2.59, p = 0.02), the mean PPD (OR = 2.23, p = 0.04), the FMBS (OR = 4.09, p = 0.04), and number of implants (OR = 4.59, p = 0.02).

CONCLUSIONS: Despite significant improvements of clinical signs of peri-implant inflammation, the use of GPAP appears to have no adjunctive effect as compared with Fm-UD alone in the achievement of DR. Elevated initial levels of bleeding and PD predicted inferior likelihood of reaching disease resolution. The present randomized parallel arm clinical study was registered on Clinicaltrials.gov and received the following registration number: NCT05801315. This clinical trial was not registered prior to participant recruitment and randomization (https://register.

CLINICALTRIALS: gov/prs/app/action/SelectProtocol?sid=S0009965&selectaction=Edit&uid=U0004FXM&ts=2&cx=fje7l8).}, } @article {pmid38315018, year = {2024}, author = {Jang, E-Y and Yang, SB and Chun, J and Kim, C and Moon, J-H and Lee, J-H}, title = {Draft genome sequence of Limosilactobacillus fermentum isolated from subgingival biofilm.}, journal = {Microbiology resource announcements}, volume = {}, number = {}, pages = {e0028023}, doi = {10.1128/mra.00280-23}, pmid = {38315018}, issn = {2576-098X}, abstract = {Limosilactobacillus fermentum is generally considered beneficial for vaginal and digestive health. However, strains isolated from the oral cavity, especially from periodontitis lesions, have not been thoroughly studied. Here, we report the draft genome sequence of strain KHUD_007 isolated from the subgingival biofilm of a Korean patient with periodontitis.}, } @article {pmid38315006, year = {2024}, author = {Cucić, S and Ells, T and Guri, A and Kropinski, AM and Khursigara, CM and Anany, H}, title = {Degradation of Listeria monocytogenes biofilm by phages belonging to the genus Pecentumvirus.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0106223}, doi = {10.1128/aem.01062-23}, pmid = {38315006}, issn = {1098-5336}, abstract = {Listeria monocytogenes is a pathogenic foodborne bacterium that is a significant cause of mortality associated with foodborne illness and causes many food recalls attributed to a bacteriological cause. Their ability to form biofilms contributes to the persistence of Listeria spp. in food processing environments. When growing as biofilms, L. monocytogenes are more resistant to sanitizers used in the food industry, such as benzalkonium chloride (BAC), as well as to physical stresses like desiccation and starvation. Lytic phages of Listeria are antagonistic to a broad range of Listeria spp. and may, therefore, have utility in reducing the occurrence of Listeria-associated food recalls by preventing food contamination. We screened nine closely related Listeria phages, including the commercially available Listex P100, for host range and ability to degrade microtiter plate biofilms of L. monocytogenes ATCC 19111 (serovar 1/2a). One phage, CKA15, was selected and shown to rapidly adsorb to its host under conditions relevant to applying the phage in dairy processing environments. Under simulated dairy processing conditions (SDPC), CKA15 caused a 2-log reduction in Lm19111 biofilm bacteria. This work supports the biosanitation potential of phage CKA15 and provides a basis for further investigation of phage-bacteria interactions in biofilms grown under SDPC.IMPORTANCEListeria monocytogenes is a pathogenic bacterium that is especially dangerous for children, the elderly, pregnant women, and immune-compromised people. Because of this, the food industry takes its presence in their plants seriously. Food recalls due to L. monocytogenes are common with a high associated economic cost. In food-processing plants, Listeria spp. typically reside in biofilms, which are structures produced by bacteria that shield them from environmental stressors and are often attached to surfaces. The significance of our work is that we show a bacteriophage-a virus-infecting bacteria-can reduce Listeria counts by two orders of magnitude when the bacterial biofilms were grown under simulated dairy processing conditions. This work provides insights into how phages may be tested and used to develop biosanitizers that are effective but are not harmful to the environment or human health.}, } @article {pmid38314962, year = {2024}, author = {Ratsoma, FM and Mokoena, NZ and Santana, QC and Wingfield, BD and Steenkamp, ET and Motaung, TE}, title = {Characterization of the Fusarium circinatum biofilm environmental response role.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300536}, pmid = {38314962}, issn = {1521-4028}, support = {129580//South African National Research Foundation (NRF)/ ; 98353//South African National Department of Science and Innovation-NRF Centers of Excellence program and South African Research Chairs Initiative/ ; }, abstract = {The capacity to form biofilms is a common trait among many microorganisms present on Earth. In this study, we demonstrate for the first time that the fatal pine pitch canker agent, Fusarium circinatum, can lead a biofilm-like lifestyle with aggregated hyphal bundles wrapped in extracellular matrix (ECM). Our research shows F. circinatum's ability to adapt to environmental changes by assuming a biofilm-like lifestyle. This was demonstrated by varying metabolic activities exhibited by the biofilms in response to factors like temperature and pH. Further analysis revealed that while planktonic cells produced small amounts of ECM per unit of the biomass, heat- and azole-exposed biofilms produced significantly more ECM than nonexposed biofilms, further demonstrating the adaptability of F. circinatum to changing environments. The increased synthesis of ECM triggered by these abiotic factors highlights the link between ECM production in biofilm and resistance to abiotic stress. This suggests that ECM-mediated response may be one of the key survival strategies of F. circinatum biofilms in response to changing environments. Interestingly, azole exposure also led to biofilms that were resistant to DNase, which typically uncouples biofilms by penetrating the biofilm and degrading its extracellular DNA; we propose that DNases were likely hindered from reaching target cells by the ECM barricade. The interplay between antifungal treatment and DNase enzyme suggests a complex relationship between eDNA, ECM, and antifungal agents in F. circinatum biofilms. Therefore, our results show how a phytopathogen's sessile (biofilm) lifestyle could influence its response to the surrounding environment.}, } @article {pmid38312767, year = {2023}, author = {Zubair, R and Mughal, S and Rathi, S and Ejaz, R}, title = {Exploring the Efficacy of ZB-06 Vaginal Biofilm as a Novel Treatment for Recurrent Bacterial Vaginosis.}, journal = {Journal of mid-life health}, volume = {14}, number = {3}, pages = {230-232}, doi = {10.4103/jmh.jmh_119_23}, pmid = {38312767}, issn = {0976-7800}, abstract = {The purpose of this research was to investigate the efficacy of ZB-06 vaginal biofilm as a novel treatment for recurrent bacterial vaginosis (BV). BV is a prevalent vaginal infection that primarily affects women of reproductive age and is linked to adverse health outcomes. Biofilm production allows bacteria to cling to the vaginal epithelium, making antibiotics harder to penetrate and treat the illness efficiently. ZB-06 is a vaginal biofilm inhibitor that may dissolve the biofilm generated by the bacteria causing BV, enhancing antibiotic therapy efficacy and lowering the risk of recurrence. The current literature on BV, biofilm formation, and the possible function of ZB-06 as a therapy option for recurrent BV is reviewed in this article. More research is needed to determine ZB-06's safety and efficacy.}, } @article {pmid38311321, year = {2024}, author = {Córdova-González, D and Alfonseca-Silva, E and Gutiérrez, L and Tapia-Pérez, G and Sumano, H}, title = {Intramammary preparation of enrofloxacin hydrochloride-dihydrate for bovine mastitis (biofilm-forming Staphylococcus aureus).}, journal = {Journal of veterinary science}, volume = {25}, number = {1}, pages = {e6}, doi = {10.4142/jvs.23245}, pmid = {38311321}, issn = {1976-555X}, support = {ITT200322//PAPIIT/Mexico ; //Edgar Alfonseca-Silva/Mexico ; }, abstract = {BACKGROUND: Chronic bovine mastitis is linked to biofilm-producing Staphylococcus aureus (bp-Sa) or Staphylococcus coagulase-negative (bp-Scn).

OBJECTIVES: Bp-Sa and bp-Scn were treated with intramammary preparations of either enrofloxacin HCl·2H2O-dimethyl-sulfoxide-chitosan (enro-C/DMSO/chitosan) or enro-C alone. Their potential to inhibit and degrade biofilm formation in vitro was also assessed.

METHODS: Milk samples were obtained from the affected quarters in a herd. Phenotypical and genotypical identifications as biofilm-producing Staphylococcus species were carried out. Enro-C/DMSO/chitosan and enro-C alone were assessed to determine their in vitro efficacy in interfering with biofilm formation and their bactericidal effects. A prolonged eight-day treatment with a twice-daily intramammary insertion of 10 mL of enro-C/DMSO/chitosan or enro-C alone was set to evaluate the clinical and bacteriological cures on day 10 in 15 cows per group and the biofilm-inhibiting ability.

RESULTS: Fifty-seven percent of the isolates were identified as Staphylococcus spp., of which 50% were bp-Sa, 46% bp-Scn, and 4% Staphylococcus pseudintermedius. One hundred percent of the S. aureus isolated and 77% of Staphylococcus coagulase-negative were biofilm producers. In both groups, the icaA and icaD biofilm-producing genes were identified. The experimental preparation could inhibit biofilm formation, degrade mature biofilms, and have well-defined microbicidal effects on planktonic and biofilm bacteria. The respective clinical and bacteriological cure rates were 100% and 80% for enro-C/DMSO/chitosan and 41.7% and 25% for enro-C alone.

CONCLUSIONS: Enro-C/DMSO/chitosan eliminates bp-Sa and bp-Scn from cases of chronic bovine mastitis.}, } @article {pmid38310999, year = {2024}, author = {Niinikoski, V and Barkoff, AM and Mertsola, J and He, Q}, title = {Bordetella pertussis isolates in Finland after acellular vaccination: serotype change and biofilm formation.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cmi.2024.01.021}, pmid = {38310999}, issn = {1469-0691}, abstract = {OBJECTIVES: In Finland, whole cell pertussis vaccine (wP) was introduced in 1952 and was replaced by acellular pertussis vaccine (aP) without fimbrial (FIM) antigen in 2005. We aimed to analyze the changes in serotypes of circulating Bordetella pertussis before and after acellular vaccination, and to explore the relationship between biofilm formation and serotype diversity after introduction of aP vaccine.

METHODS: Serotyping of 1399 B. pertussis isolates collected at the Finnish National Reference Laboratory for Pertussis and Diphtheria in Turku, Finland during 1974-2023 was performed by slide agglutination or indirect ELISA. Of 278 isolates collected after 2005, 53 were selected, genotyped for fim3 and fim2 alleles and tested for biofilm formation. The selection criteria included maintaining a relatively equal distribution of isolates per time interval, ensuring approximately a 50:50 ratio of FIM2 (N=26) and FIM3 (N=27) serotypes. The reference strain Tohama I was used as control.

RESULTS: During the wP era the majority of circulating B. pertussis exhibited FIM2 serotype. However, FIM3 strains have appeared since 1999 and become prevalent. After implementation of aP vaccines the distribution of serotypes has exhibited substantial variability. FIM3 isolates displayed an enhanced biofilm formation compared to FIM2 isolates (Geometric mean value (95% CI): 0,90 (0.79-1.03) vs 0,75 (0.65-0.85); p<0,05). Of the 27 FIM3 isolates, 8 harbored fim3-1 and 19 fim3-2 alleles. FIM3 isolates with fim3-2 allele was significantly associated with increased biofilm formation compared to those with fim3-1 (1,07 (0.96-1.19) vs 0,61 (0.52-0.72); p<0,0001).

CONCLUSION: Following the implementation of aP vaccines, the distribution of serotypes in Finland has exhibited substantial variability. FIM3 isolates with fim3-2 allele displayed an enhanced biofilm formation capability compared to FIM2 isolates.}, } @article {pmid38310778, year = {2024}, author = {Cai, Z and Huang, W and Zhong, J and Jin, J and Wu, D and Chen, K}, title = {Methyl jasmonate-loaded composite biofilm sustainably alleviates chilling lignification of loquat fruit during postharvest storage.}, journal = {Food chemistry}, volume = {444}, number = {}, pages = {138602}, doi = {10.1016/j.foodchem.2024.138602}, pmid = {38310778}, issn = {1873-7072}, abstract = {In this work, the MeJA-loaded gelatin/pullulan/chitosan composite biofilm was prepared to inhibit the chilling lignification of the loquat fruit during storage at 0 °C. The firmness and lignin content were decreased by 89 % and 81.77 % after MeJA-loaded biofilm treatment. Malondialdehyde (MDA) production was almost completely suppressed and chilling injury of loquat fruit was significantly reduced. Enzyme activity results show that the biofilm alleviated chilling lignification mainly by inhibiting peroxidase (POD) activity in the phenylpropanoid pathway (PCCs = 0.715, with lignin content). Also, the conventional MeJA vapor treatment only alleviated lignification on day 3, but the biofilm treatment had a better and more sustained effect throughout the whole storage due to its sustained release ability. Besides, the biofilm had good mechanical properties, transparency and water vapor transmission rate. This work indicates that loading preservatives into biofilms has a promising application prospect for inhibiting the postharvest quality deterioration of fruit and vegetables.}, } @article {pmid38310144, year = {2024}, author = {Duff, AF and Jurcisek, JA and Kurbatfinski, N and Chiang, T and Goodman, SD and Bakaletz, LO and Bailey, MT}, title = {Oral and middle ear delivery of otitis media standard of care antibiotics, but not biofilm-targeted antibodies, alter chinchilla nasopharyngeal and fecal microbiomes.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {10}, pmid = {38310144}, issn = {2055-5008}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; }, abstract = {Otitis media (OM) is one of the most globally pervasive pediatric conditions. Translocation of nasopharynx-resident opportunistic pathogens like nontypeable Haemophilus influenzae (NTHi) assimilates into polymicrobial middle ear biofilms, which promote OM pathogenesis and substantially diminish antibiotic efficacy. Oral or tympanostomy tube (TT)-delivered antibiotics remain the standard of care (SOC) despite consequences including secondary infection, dysbiosis, and antimicrobial resistance. Monoclonal antibodies (mAb) against two biofilm-associated structural proteins, NTHi-specific type IV pilus PilA (anti-rsPilA) and protective tip-region epitopes of NTHi integration host factor (anti-tip-chimer), were previously shown to disrupt biofilms and restore antibiotic sensitivity in vitro. However, the additional criterion for clinical relevance includes the absence of consequential microbiome alterations. Here, nine chinchilla cohorts (n = 3/cohort) without disease were established to evaluate whether TT delivery of mAbs disrupted nasopharyngeal or fecal microbiomes relative to SOC-OM antibiotics. Cohort treatments included a 7d regimen of oral amoxicillin-clavulanate (AC) or 2d regimen of TT-delivered mAb, AC, Trimethoprim-sulfamethoxazole (TS), ofloxacin, or saline. Fecal and nasopharyngeal lavage (NPL) samples were collected before and several days post treatment (DPT) for 16S sequencing. While antibiotic-treated cohorts displayed beta-diversity shifts (PERMANOVA, P < 0.05) and reductions in alpha diversity (q < 0.20) relative to baseline, mAb antibodies failed to affect diversity, indicating maintenance of a eubiotic state. Taxonomic and longitudinal analyses showed blooms in opportunistic pathogens (ANCOM) and greater magnitudes of compositional change (P < 0.05) following broad-spectrum antibiotic but not mAb treatments. Collectively, results showed broad-spectrum antibiotics induced significant fecal and nasopharyngeal microbiome disruption regardless of delivery route. Excitingly, biofilm-targeting antibodies had little effect on fecal and nasopharyngeal microbiomes.}, } @article {pmid38309565, year = {2024}, author = {Saygin, H and Tilkili, B and Kayisoglu, P and Baysal, A}, title = {Oxidative stress, biofilm-formation and activity responses of P. aeruginosa to microplastic-treated sediments: Effect of temperature and sediment type.}, journal = {Environmental research}, volume = {}, number = {}, pages = {118349}, doi = {10.1016/j.envres.2024.118349}, pmid = {38309565}, issn = {1096-0953}, abstract = {Climate change and plastic pollution are the big environmental problems that the environment and humanity have faced in the past and will face in many decades to come. Sediments are affected by many pollutants and conditions, and the behaviors of microorganisms in environment may be influenced due to changes in sediments. Therefore, the current study aimed to explore the differential effects of various microplastics and temperature on different sediments through the metabolic and oxidative responses of gram-negative Pseudomonas aeruginosa. The sediments collected from various fields including beaches, deep-sea discharge, and marine industrial areas. Each sediment was extracted and then treated with various microplastics under different temperature (-18, +4, +20 and 35 °C) for seven days. Then microplastics were removed from the suspension and microplastic-exposed sediment samples were incubated with Pseudomonas aeruginosa to test bacterial activity, biofilm, and oxidative characteristics. The results showed that both the activity and the biofilm formation of Pseudomonas aeruginosa increased with the temperature of microplastic treatment in the experimental setups at the rates between an average of 2-39 % and 5-27 %, respectively. The highest levels of bacterial activity and biofilm formation were mainly observed in the beach area (average rate +25 %) and marine industrial (average rate +19 %) sediments with microplastic contamination, respectively. Moreover, oxidative characteristics significantly linked the bacterial activities and biofilm formation. The oxidative indicators of Pseudomonas aeruginosa showed that catalase and glutathione reductase were more influenced by microplastic contamination of various sediments than superoxide dismutase activities. For instance, catalase and glutathione reductase activities were changed between -37 and +169 % and +137 to +144 %, respectively; however, the superoxide dismutase increased at a rate between +1 and + 21 %. This study confirmed that global warming as a consequence of climate change might influence the effect of microplastic on sediments regarding bacterial biochemical responses and oxidation characteristics.}, } @article {pmid38309052, year = {2024}, author = {Yun, S and Huang, J and Zhang, M and Wang, X and Wang, X and Zhou, Y}, title = {Preliminary identification and semi-quantitative characterization of a multi-faceted high-stability alginate lyase from marine microbe Seonamhaeicola algicola with anti-biofilm effect on Pseudomonas aeruginosa.}, journal = {Enzyme and microbial technology}, volume = {175}, number = {}, pages = {110408}, doi = {10.1016/j.enzmictec.2024.110408}, pmid = {38309052}, issn = {1879-0909}, abstract = {Alginate lyases with unique characteristics for degrading alginate into size-defined oligosaccharide fractions, were considered as the potential agents for disrupting Pseudomonas aeruginosa biofilms. In our study, a novel endolytic PL-7 alginate lyase, named AlyG2, was cloned and expressed through Escherichia coli. This enzyme exhibited excellent properties: it maintained more than 85% activity at low temperatures of 4 °C and high temperatures of 70 °C. After 1 h of incubation at 4 °C, it still retained over 95% activity, demonstrating the ability to withstand low temperature. The acid-base and salt tolerance properties shown it preserves more than 50% activity in the pH range of 5.0 to 11.0 and in a high salt environment at 3000 mM NacCl, indicating its high stability in several aspects. More importantly, AlyG2 in our research was revealed to be effective at removing mature biofilms and inhibiting biofilm formation produced by Pseudomonas aeruginosa, and the inhibition and disruption rates were 47.25 ± 4.52% and 26.5 ± 6.72%, respectively. Additionally, the enzyme AlyG2 promoted biofilm disruption in combination with antibiotics, particularly manifesting the synergistic effect with erythromycin (FIC=0.5). In all, these results offered that AlyG2 with unique characteristics may be an effective technique for the clearance or disruption of biofilm produced by P. aeruginosa.}, } @article {pmid38308703, year = {2024}, author = {Zaffar, R and Nazir, R and Rather, MA and Dar, R}, title = {Biofilm formation and EPS production enhances the bioremediation potential of Pseudomonas species: a novel study from eutrophic waters of Dal lake, Kashmir, India.}, journal = {Archives of microbiology}, volume = {206}, number = {3}, pages = {89}, pmid = {38308703}, issn = {1432-072X}, support = {SR/WOS-A/LS-232/2018//Department of Science and Technology, Ministry of Science and Technology, India/ ; }, abstract = {The present study was conducted with the aim of isolation and identification of the biofilm-forming denitrifying Pseudomonas bacterial strains from eutrophic waters of Dal lake, India, followed by the study of inter-relation of biofilm formation and denitrification potential of Pseudomonas strains. The bacterial strains were characterized by morphological observations and identified using 16S rDNA sequencing followed by the quantification of biofilm formation of these st by crystal violet (CV) assay using 96-well microtiter plate and extracellular polymeric substance (EPS) extraction. Lastly, the nitrate-reducing potential of all Pseudomonas species was studied. Our evaluation revealed that four different Pseudomonas species were observed to have the biofilm-forming potential and nitrate-reducing properties and the species which showed maximum biofilm-forming potential and maximum EPS production exhibited higher nitrate-removing capacity. Moreover, P. otitis was observed to have the highest denitrification capacity (89%) > P. cedrina (83%) > P. azotoform (79%) and the lowest for P. peli (70%). These results clearly signify a positive correlation of biofilm-forming capacity and nitrate-removing ability of Pseudomonas species. This study has for the first time successfully revealed the bioremediation potential of P. otitis, P. cedrina, P. azotoform, and P. peli species, thus contributing to the growing list of known nitrate-reducing Pseudomonas species. Based upon the results, these strains can be extrapolated to nitrate-polluted water systems for combating water pollution.}, } @article {pmid38306825, year = {2024}, author = {Li, J and Yu, Y and Zhou, Y and Song, J and Yang, A and Wang, M and Li, Y and Wan, M and Zhang, C and Yang, H and Bai, Y and Wong, WL and Pu, H and Feng, X}, title = {Multi-targeting oligopyridiniums: Rational design for biofilm dispersion and bacterial persister eradication.}, journal = {Bioorganic chemistry}, volume = {144}, number = {}, pages = {107163}, doi = {10.1016/j.bioorg.2024.107163}, pmid = {38306825}, issn = {1090-2120}, abstract = {The development of effective antibacterial drugs to combat bacterial infections, particularly the biofilm-related infections, remains a challenge. There are two important features of bacterial biofilms, which are well-known critical factors causing biofilms hard-to-treat in clinical, including the dense and impermeable extracellular polymeric substances (EPS) and the metabolically repressed dormant and persistent bacterial population embedded. These characteristics largely increase the difficulty for regular antibiotic treatment due to insufficient penetration into EPS. In addition, the dormant bacteria are insensitive to the growth-inhibiting mechanism of traditional antibiotics. Herein, we explore the potential of a series of new oligopyridinium-based oligomers bearing a multi-biomacromolecule targeting function as the potent bacterial biofilm eradication agent. These oligomers were rationally designed to be "charge-on-backbone" that can offer a special alternating amphiphilicity. This novel and unique feature endows high affinity to bacterial membrane lipids, DNAs as well as proteins. Such a broad multi-targeting nature of molecules not only enables its penetration into EPS, but also plays vital roles in the bactericidal mechanism of action that is highly effective against dormant and persistent bacteria. Our in vitro, ex vivo, and in vivo studies demonstrated that OPc3, one of the most effective derivatives, was able to offer excellent antibacterial potency against a variety of bacteria and effectively eliminate biofilms in zebrafish models and mouse wound biofilm infection models.}, } @article {pmid38306747, year = {2024}, author = {Zhu, Z and Huang, C and Liu, L and Wang, J and Gou, X}, title = {Magnetically actuated pandanus fruit-like nanorobots for enhanced pH-stimulated drug release and targeted biofilm elimination in wound healing.}, journal = {Journal of colloid and interface science}, volume = {661}, number = {}, pages = {374-388}, doi = {10.1016/j.jcis.2024.01.197}, pmid = {38306747}, issn = {1095-7103}, abstract = {Conventional antibiotic treatment struggles to eliminate biofilms in wounds due to the formation compact barrier. Herein, we fabricate magnetic pandanus fruit-like nanorobots (NRs) that function as drug carriers while exhibit excellent maneuverability for enhanced antibacterial tasks. Specifically, zeolitic imidazolate framework-8 (ZIF-8) is self-assembled on the surface of Fe3O4 nanoparticles, loaded with a small quantity of ciprofloxacin, and covered with a layer of polydopamine (PDA). Energized by external magnetic fields, the NRs (F@Z/C/P) are steered in defined direction to penetrate the infection tissues, and effectively arrive targeted areas for pH stimulated drug release and near-infrared triggered phototherapy, contributing to an antibacterial rate of >99.9 %. The Zn[2+] in ZIF-8 and the catechol group in PDA form catechol-ZIF-8-drug structures, which effectively reduce drug release by 11 % in high pH environments and promote rapid drug release by 14 % in low pH environments compared to NRs without PDA. Additionally, F@Z/C/P can remove the biofilms and bacteria in Staphylococcus aureus infected wounds, and eventually be discharged from the infected site after treatment, leading to faster healing with an intact epidermis and minimal harm to surrounding tissues and organs. The study provides a promising strategy for tackling biofilm-associated infections in vivo through the use of multi-functional NRs.}, } @article {pmid38305425, year = {2024}, author = {Nishimata, H and Kamasaki, Y and Satoh, K and Kinoshita, R and Omori, K and Hoshino, T}, title = {Suppression of Streptococcus mutans Biofilm Formation and Gene Expression by PRG Barrier Coat: A Molecular and Microscopic Study for Preventing Dental Caries.}, journal = {Oral health & preventive dentistry}, volume = {22}, number = {1}, pages = {73-79}, doi = {10.3290/j.ohpd.b4928623}, pmid = {38305425}, issn = {1757-9996}, abstract = {PURPOSE: This study aimed to investigate the inhibitory effect of a PRG Barrier Coat on biofilm formation and structure by Streptococcus mutans and propose an effective method for preventing dental caries.

MATERIALS AND METHODS: Streptococcus mutans MT8148 biofilms were obtained from hydroxyapatite disks with and with- out a PRG Barrier Coat. Scanning electron microscopy (SEM) was used to observe the 12- and 24-h-cultured biofilms, while reverse-transcription polymerase chain reaction (qRT-PCR) was used to quantify caries-related genes. Biofilm adhe- sion assessments were performed on glass. Statistical analysis was performed using a two-sample t-test.

RESULTS: A statistically significant difference in Streptococcus mutans biofilm adhesion rate was observed between the con- trol and PRG Barrier Coat-coated samples (p < 0.01). However, there was no statistically significant difference in total bacter- ial count or biofilm volume (p > 0.05). SEM revealed that the PRG Barrier Coat inhibited biofilm formation by Streptococcus mutans. Real-time RT-PCR revealed that the material restricted the expression of genes associated with caries-related bio- film formation. However, the suppression of gtfD and dexB differed from that of other genes.

CONCLUSION: PRG Barrier Coat suppressed biofilm formation by Streptococcus mutans by inhibiting the expression of in- soluble glucan synthase, which is associated with primary biofilm formation. The material also affected gene expression and altered the biofilm structure. Tooth surface-coating materials, such as PRG Barrier Coat, may improve caries preven- tion in dental practice.}, } @article {pmid38305226, year = {2024}, author = {Wang, H and Fan, Q and Gao, S and Yi, L and Wang, Y and Wang, Y}, title = {Transposon library screening to identify genes with a potential role in Streptococcus suis biofilm formation.}, journal = {Future microbiology}, volume = {}, number = {}, pages = {}, doi = {10.2217/fmb-2023-0181}, pmid = {38305226}, issn = {1746-0921}, support = {232102110095//He'nan Provincial Science and Technology Research Project/ ; 32172852, 31902309//National Natural Science Foundation of China/ ; 222300420005//Excellent Youth Foundation of He'nan Scientific Committee/ ; }, abstract = {Background: Biofilm formation is considered to be one of reasons for difficulty in the prevention and control of Streptococcus suis. Aims: To explore the potential genes involved in the biofilm formation of S. suis. Methods: Transposon mutagenesis technology was used to screen biofilm-defective strains of S. suis, and the potential genes related to biofilm were identified. Results: A total of 19 genes were identified that were involved in bacterial metabolism, peptidoglycan-binding protein, cell wall synthesis, ABC transporters, and so on. Conclusion: This study constructed 979 transposon mutation libraries of S. suis. A total of 19 gene loci related to the formation of S. suis biofilm were identified, providing a reference for exploring the mechanism of S. suis biofilm formation in the future.}, } @article {pmid38304929, year = {2024}, author = {Dhara, SR and Saha, R and Baildya, N and Acharya, K and Bhattacharya, A and Ghosh, K}, title = {New Cyanostyrylcopillar[5]arene Derivative: Synthesis, Photophysical Study, Chromogenic Detection of Aliphatic Amines, and Biofilm-Antibiofilm Activity.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c16248}, pmid = {38304929}, issn = {1944-8252}, abstract = {The synthesis, characterization, and application of a new cyanostyrylcopillar[5]arene 1 is reported. Single-crystal X-ray diffraction and other spectroscopic techniques confirm the identity of the new copillar 1. The X-ray diffraction study reveals that the copillar 1 exhibits a 1D supramolecular chain in the solid state involving π···π interactions along the crystallographic c-axis and 1D chains are further connected by interchain C-H···π interactions to establish 2D supramolecular layers within the crystallographic bc-plane. 2D supramolecular chains on further packing introduce a 3D structure with void spaces filled with hexane molecules. Through minimal deviation in the dihedral angle, the cyano-substituted ethylenic group in 1 shows a conjugation with the phenolic -OH, favoring intramolecular bond conjugation (ITBC) and colorimetrically detects the aliphatic amines over aromatic amines in CH3CN. Among the aliphatic amines, tertiary amines are differentiated from primary and secondary amines by the naked eye through color change. Both in solution and solid states, 1 displays vapor phase detection of volatile aliphatic amines. Antibacterial activity analysis shows that while 1 exhibits the antibiofilm action against Gram-positive pathogenic bacteria, Staphylococcus aureus, it promotes biofilm formation by Gram-negative pathogenic bacteria, Pseudomonas aeruginosa.}, } @article {pmid38303387, year = {2024}, author = {Haque, MM and Hossen, MN and Rahman, A and Roy, J and Talukder, MR and Ahmed, M and Ahiduzzaman, M and Haque, MA}, title = {Decolorization, degradation and detoxification of mutagenic dye Methyl orange by novel biofilm producing plant growth-promoting rhizobacteria.}, journal = {Chemosphere}, volume = {346}, number = {}, pages = {140568}, doi = {10.1016/j.chemosphere.2023.140568}, pmid = {38303387}, issn = {1879-1298}, abstract = {Discharge of untreated dyeing wastewater nearby water-bodies is one of major causes of water pollution. Generally, bacterial strains isolated from industrial effluents and/or contaminated soils are used for the bioremediation of Methyl orange (MO), a mutagenic recalcitrant mono-azo dye, used in textiles and biomedical. However, MO degradation by biofilm producing plant growth-promoting rhizobacteria (BPPGPR) was not studied yet. In this study, 19 out of 21 BPPGPR strains decolorized 96.3-99.9% and 89.5-96.3% MO under microaerophilic and aerobic conditions, respectively from Luria-Bertani broth (LBB) followed by yeast-extract peptone and salt-optimized broth plus glycerol media within 120 h of incubation at 28 °C. Only selected BPPGPR including Pseudomonas fluorescens ESR7, P. veronii ESR13, Stenotrophomonas maltophilia ESR20, Staphylococcus saprophyticus ESD8, and P. parafulva ESB18 were examined for process optimization of MO decolorization using a single factor optimization method. This study showed that under optimal conditions (e.g., LBB, 100 mg L[-1] MO, pH 7, incubation of 96 h, 28 °C), these strains could remove 99.1-99.8% and 97.6-99.5% MO under microaerophilic and aerobic conditions, respectively. Total azoreductase and laccase activities responsible for biodegradation were also remarkably activated in the biodegraded samples under optimal conditions, while these activities were repressed under unfavorable conditions (e.g., 40 °C and 7.5% NaCl). This study confirmed that MO was degraded and detoxified by these bacterial strains through breakage of azo bond. So far, this is the first report on bioremediation of MO by the BPPGPR strains. These BPPGPR strains are highly promising to be utilized for the bioremediation of dyeing wastewater in future.}, } @article {pmid38301897, year = {2024}, author = {Roy, S and Bhogapurapu, B and Chandra, S and Biswas, K and Mishra, P and Ghosh, A and Bhunia, A}, title = {Host antimicrobial peptide S100A12 disrupts the fungal membrane by direct binding and inhibits growth and biofilm formation of Fusarium species.}, journal = {The Journal of biological chemistry}, volume = {}, number = {}, pages = {105701}, doi = {10.1016/j.jbc.2024.105701}, pmid = {38301897}, issn = {1083-351X}, abstract = {Fungal keratitis is the foremost cause of corneal infections worldwide of which Fusarium spp. is the common etiological agent that causes loss of vision and warrants surgical intervention. An increase in resistance to the available drugs along with severe side effects of existing antifungals demands for new effective antimycotics. Here, we demonstrate that antimicrobial peptide S100A12 directly binds to the phospholipids of the fungal membrane, disrupts the structural integrity and induces generation of reactive oxygen species in fungus. Additionally, it inhibits biofilm formation by Fusarium spp. and exhibits antifungal property against Fusarium spp. both in vitro and in vivo. Taken together, our results delve into specific effect of S100A12 against Fusarium spp. with an aim to investigate new antifungal compounds to combat fungal keratitis.}, } @article {pmid38301542, year = {2024}, author = {Hartono Adji, RP and Anshori, I and Manurung, RV and Taufiqqurrachman, and Mahmudin, D and Daud, P and Kurniadi, DP and Pristianto, EJ and Rahman, AN and Desvasari, W and Sulistyaningsih, and Mandasari, RD and Hiskia, and Wiranto, G}, title = {A comprehensive study on transparent conducting oxides in compact microbial fuel cells: Integrated spectroscopic and electrochemical analyses for monitoring biofilm growth.}, journal = {Biosensors & bioelectronics}, volume = {250}, number = {}, pages = {116067}, doi = {10.1016/j.bios.2024.116067}, pmid = {38301542}, issn = {1873-4235}, abstract = {Microbial fuel cells (MFCs) are an emerging technology that holds promise for renewable energy production and the mitigation of environmental challenges. This research paper introduces a single-compartment MFC reactor that utilizes transparent conducting oxides (TCOs), such as fluorine-doped tin oxide (FTO) and indium tin oxides (ITO), as the working electrodes. The effectiveness of MFCs based on FTO and ITO was evaluated by characterizing the transparent electrode and examining its performance during biofilm cultivation. Additionally, the optical properties of the biofilm grown directly on these electrodes were investigated using LEDs as a light source. The impressive average current density of 200 μA cm[-2] over 100 days demonstrates the efficiency of the see-through electrodes in bioenergy extraction. The correlation between spectroscopic and microscopic analyses substantiates the feasibility of employing transparent electrodes for accurate quantification of biofilm thickness, with an initial accuracy of ±10 μm in the initial cycle, ±22 μm in the subsequent cycle, and a maximum of ±31 μm after seven days of growth. This innovative approach holds great potential for advancing our understanding of MFCs and their application in environmentally friendly energy generation and optical-based monitoring.}, } @article {pmid38301541, year = {2024}, author = {Byun, KH and Han, SH and Choi, MW and Kim, BH and Ha, SD}, title = {Efficacy of disinfectant and bacteriophage mixture against planktonic and biofilm state of Listeria monocytogenes to control in the food industry.}, journal = {International journal of food microbiology}, volume = {413}, number = {}, pages = {110587}, doi = {10.1016/j.ijfoodmicro.2024.110587}, pmid = {38301541}, issn = {1879-3460}, abstract = {Fresh produce and animal-based products contaminated with Listeria monocytogenes have been the main cause of listeriosis outbreaks for many years. The present investigation explored the potential of combination treatment of disinfectants with a bacteriophage cocktail to control L. monocytogenes contamination in the food industry. A mixture of 1 minimal inhibitory concentration (MIC) of disinfectants (sodium hypochlorite [NaOCl], hydrogen peroxide [H2O2], and lactic acid [LA]) and multiplicity of infection (MOI) 100 of phage cocktail was applied to both planktonic cells in vitro and already-formed biofilm cells on food contact materials (FCMs; polyethylene, polypropylene, and stainless steel) and foods (celery and chicken meat). All the combinations significantly lowered the population, biofilm-forming ability, and the expression of flaA, motB, hlyA, prfA, actA, and sigB genes of L. monocytogenes. Additionally, in the antibiofilm test, approximately 4 log CFU/cm[2] was eradicated by 6 h treatment on FCMs, and 3 log CFU/g was eradicated within 3 days on celery. However, <2 log CFU/g was eradicated in chicken meat, and regrowth of L. monocytogenes was observed on foods after 5 days. The biofilm eradication efficacy of the combination treatment was proven through visualization using scanning electron microscopy (SEM) and confocal microscopy. In the SEM images, the unusual behavior of L. monocytogenes invading from the surface to the inside was observed after treating celery with NaOCl+P or H2O2 + P. These results suggested that combination of disinfectants (NaOCl, H2O2, and LA) with Listeria-specific phage cocktail can be employed in the food industry as a novel antimicrobial and antibiofilm approach, and further research of L. monocytogenes behavior after disinfection is needed.}, } @article {pmid38300444, year = {2024}, author = {Yates, MD and Mickol, RL and Vignola, A and Baldwin, JW and Glaven, SM and Tender, LM}, title = {Performance of a combined electrotrophic and electrogenic biofilm operated under long-term, continuous cycling.}, journal = {Biotechnology letters}, volume = {}, number = {}, pages = {}, pmid = {38300444}, issn = {1573-6776}, support = {Internal Base Funding//US Naval Research Laboratory/ ; }, abstract = {OBJECTIVES: Evaluate electrochemically active biofilms as high energy density rechargeable microbial batteries toward providing persistent power in applications where traditional battery technology is limiting (, remote monitoring applications).

RESULTS: Here we demonstrated that an electrochemically active biofilm was able to store and release electrical charge for alternating charge/discharge cycles of up to 24 h periodicity (50% duty cycle) with no significant decrease in average current density (0.16 ± 0.04 A/m[2]) for over 600 days. However, operation at 24 h periodicity for > 50 days resulted in a sharp decrease in the current to nearly zero. This current crash was recoverable by decreasing the periodicity. Overall, the coulombic efficiency remained near unity within experimental error (102 ± 3%) for all of the tested cycling periods. Electrochemical characterization here suggests that electron transfer occurs through multiple routes, likely a mixture of direct and mediated mechanisms.

CONCLUSIONS: These results indicate that bidirectional electrogenic/electrotrophic biofilms are capable of efficient charge storage/release over a wide range of cycling frequency and may eventually enable development of sustainable, high energy density rechargeable batteries.}, } @article {pmid38300317, year = {2024}, author = {Dsouza, FP and Dinesh, S and Sharma, S}, title = {Understanding the intricacies of microbial biofilm formation and its endurance in chronic infections: a key to advancing biofilm-targeted therapeutic strategies.}, journal = {Archives of microbiology}, volume = {206}, number = {2}, pages = {85}, pmid = {38300317}, issn = {1432-072X}, support = {DSRE/BNM/SR/2023/A0116//Department of Scientific Research and Education, BioNome/ ; DSRE/BNM/SR/2023/A0116//Department of Scientific Research and Education, BioNome/ ; }, abstract = {Bacterial biofilms can adhere to various surfaces in the environment with human beings being no exception. Enclosed in a self-secreted matrix which contains extracellular polymeric substances, biofilms are intricate communities of bacteria that play a significant role across various sectors and raise concerns for public health, medicine and industries. These complex structures allow free-floating planktonic cells to adopt multicellular mode of growth which leads to persistent infections. This is of great concern as biofilms can withstand external attacks which include antibiotics and immune responses. A more comprehensive and innovative approach to therapy is needed in view of the increasing issue of bacterial resistance brought on by the overuse of conventional antimicrobial medications. Thus, to oppose the challenges posed by biofilm-related infections, innovative therapeutic strategies are being explored which include targeting extracellular polymeric substances, quorum sensing, and persister cells. Biofilm-responsive nanoparticles show promising results by improving drug delivery and reducing the side effects. This review comprehensively examines the factors influencing biofilm formation, host immune defence mechanisms, infections caused by biofilms, diagnostic approaches, and biofilm-targeted therapies.}, } @article {pmid38299590, year = {2024}, author = {Bauer, TM and Gallagher, KA}, title = {Biofilm-derived oxylipin 10-HOME mediated immune response in women with breast implants.}, journal = {The Journal of clinical investigation}, volume = {134}, number = {3}, pages = {}, doi = {10.1172/JCI176547}, pmid = {38299590}, issn = {1558-8238}, abstract = {Breast implant illness (BII) is a poorly understood disease in which patients develop symptoms typical of autoimmune conditions following breast implantation. There is no known underlying cause, and patients often resort to breast implant removal and capsulectomy to alleviate symptoms. In this issue of the JCI, Khan and colleagues examined 86 breast explants from patients that reported BII symptoms and 55 control explants. The BII group showed a disproportionally high degree of biofilm, which was associated with oxylipin (10-HOME) on the implant surfaces. Injections of 10-HOME in the mammary fat pad of a murine model recapitulated BII symptoms and increased Th1 cell populations. Notably, macrophages in the periprosthetic tissue from BII patients were more likely to exhibit a proinflammatory phenotype, and naive T cells exposed to 10-HOME caused naive macrophages to differentiate to a proinflammatory phenotype. This work provides a pathophysiologic mechanism for a currently understudied and poorly characterized disease.}, } @article {pmid38298832, year = {2024}, author = {Wu, X and Wang, H and Xiong, J and Yang, GX and Hu, JF and Zhu, Q and Chen, Z}, title = {Staphylococcus aureus biofilm: Formulation, regulatory, and emerging natural products-derived therapeutics.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100175}, doi = {10.1016/j.bioflm.2023.100175}, pmid = {38298832}, issn = {2590-2075}, abstract = {Staphylococcus aureus can readily form biofilm which enhances the drug-resistance, resulting in life-threatening infections involving different organs. Biofilm formation occurs due to a series of developmental events including bacterial adhesion, aggregation, biofilm maturation, and dispersion, which are controlled by multiple regulatory systems. Rapidly increasing research and development outcomes on natural products targeting S. aureus biofilm formation and/or regulation led to an emergent application of active phytochemicals and combinations. This review aimed at providing an in-depth understanding of biofilm formation and regulation mechanisms for S. aureus, outlining the most important antibiofilm strategies and potential targets of natural products, and summarizing the latest progress in combating S. aureus biofilm with plant-derived natural products. These findings provided further evidence for novel antibiofilm drugs research and clinical therapies.}, } @article {pmid38298534, year = {2024}, author = {}, title = {Erratum: Molecular Characteristics, Antimicrobial Susceptibility, Biofilm-Forming Ability of Clinically Invasive Staphylococcus aureus Isolates [Corrigendum].}, journal = {Infection and drug resistance}, volume = {17}, number = {}, pages = {341-342}, doi = {10.2147/IDR.S461582}, pmid = {38298534}, issn = {1178-6973}, abstract = {[This corrects the article DOI: 10.2147/IDR.S441989.].}, } @article {pmid38298235, year = {2024}, author = {International, SC}, title = {Retracted: Correlation Analysis between Chronic Osteomyelitis and Bacterial Biofilm.}, journal = {Stem cells international}, volume = {2024}, number = {}, pages = {9891259}, doi = {10.1155/2024/9891259}, pmid = {38298235}, issn = {1687-966X}, abstract = {[This retracts the article DOI: 10.1155/2022/9433847.].}, } @article {pmid38296886, year = {2024}, author = {Maitreya, A and Qureshi, A}, title = {Genomic and phenotypic characterisation of Enterococcus mundtii AM_AQ_BC8 for its anti-biofilm, antimicrobial and probiotic potential.}, journal = {Archives of microbiology}, volume = {206}, number = {2}, pages = {84}, pmid = {38296886}, issn = {1432-072X}, abstract = {Enterococcus mundtii AM_AQ_BC8 isolated from biofouled filtration membrane was characterised as a potential probiotic bacterium showing strong L-lactic acid-producing capability. Experimental studies revealed that E. mundtii AM_AQ_BC8 possess antibiofilm and antimicrobial ability too, as tested against strong biofilm-forming bacteria like Pseudomonas spp. The present study has evaluated the genetic potential of E. mundtii AM_AQ_BC8 through genome sequencing. Whole genome analysis revealed the presence of key genes like ldh_1 and ldh_2 responsible for lactic acid production along with genes encoding probiotic features such as acid and bile salt resistance (dnaK, dnaJ, argS), fatty acid synthesis (fabD, fabE) and lactose utilisation (lacG, lacD). The phylogenomic analysis based on OrthoANI (99.85%) and dDDH (96.8%) values revealed that the strain AM_AQ_BC8 shared the highest homology with E. mundtii. The genome sequence of strain AM_AQ_BC8 has been deposited to NCBI and released with GenBank accession no. SAMN32531201. The study primarily demonstrated the probiotic potential of E. mundtii AM_AQ_BC8 isolate, for L-lactate synthesis in high concentration (8.98 g/L/day), which also showed anti-biofilm and antimicrobial activities.}, } @article {pmid38296539, year = {2024}, author = {Del Río-Chacón, JM and Rojas-Larios, F and Bocanegra-Ibarias, P and Salas-Treviño, D and Espinoza-Gómez, F and Camacho-Ortiz, A and Flores-Treviño, S}, title = {Biofilm eradication of Stenotrophomonas maltophilia by Levofloxacin and Trimethoprim-sulfamethoxazole.}, journal = {Japanese journal of infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.7883/yoken.JJID.2023.389}, pmid = {38296539}, issn = {1884-2836}, abstract = {Stenotrophomonas maltophilia is a non-fermenting Gram-negative drug-resistant pathogen causing healthcare-associated infections. Clinical isolates from Mexico were assessed for biofilm production by crystal violet staining. Antimicrobial susceptibility was evaluated using the broth microdilution method in planktonic and biofilm cells. The effect of antibiotics on the biofilm was visualized by fluorescence microscopy. Fifty isolates were included in the study, of which 28.0% were biofilm producers (64.2% from blood and 35.7% from respiratory samples). Resistance to levofloxacin (8.0%) and trimethoprim-sulfamethoxazole (44.0%) in planktonic cells increased to 100% in biofilm cells. Bacterial biofilm treated with several concentrations of both antibiotics was completely disrupted. In conclusion, S. maltophilia isolated from blood had higher biofilm production than those from respiratory samples. Resistance to antibiotics increased due to biofilm production. Antibiotic monotherapy might not be the best course of action for the treatment of S. maltophilia infections in Mexico, as they might also be causing biofilm production.}, } @article {pmid38296118, year = {2024}, author = {Pallavi, P and Sahoo, PP and Sen, SK and Raut, S}, title = {Comparative evaluation of anti-biofilm and anti- adherence potential of plant extracts against Streptococcus mutans: A therapeutic approach for oral health.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106514}, doi = {10.1016/j.micpath.2023.106514}, pmid = {38296118}, issn = {1096-1208}, abstract = {Dental caries predominantly attributed to the cariogenic nature of Streptococcus mutans, continue to pose a substantial global challenge to oral health. In response to this challenge, this study aimed to evaluate the effectiveness of leaf extracts (LEs) and essential oils (EOs) derived from different medicinal plants in inhibiting the formation of Streptococcus mutans biofilm. In vitro and in silico approaches were employed to identify active compounds and assess their inhibitory effects on S. mutans. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were measured to determine the anti-biofilm and anti-adherence activity against S. mutans. Biofilm viability (CFU/mL) and extracellular polymeric substance (EPS) concentration were quantified. GC-MS analysis was utilized to identify active compounds in the most effective plant extracts exhibiting anti-S. mutans activity. A high-throughput screening focused on the interaction between these compounds and the target enzyme SortaseA (SrtA) using molecular docking. Results indicated that Cymbopogon citratus displayed the highest efficacy in reducing S. mutans biofilm formation and adhesion activity, achieving 90 % inhibition at an MIC value of 12 μg/mL. Among the 12 bioactive compounds identified, trans-Carvyl acetate exhibited the lowest binding energy with SrtA (-6.0 Kcal/mole). Trans-Carvyl acetate also displayed favorable pharmacokinetic properties. This study provides novel insights into the anti-S. mutans properties of C. citratus and suggests its potential as a therapeutic approach for oral health. Further research is needed to explore combined plant extracts for enhanced protection against dental caries.}, } @article {pmid38295992, year = {2024}, author = {Sousa, AM and Ferreira, D and Rodrigues, LR and Pereira, MO}, title = {Aptamer-based therapy for fighting biofilm-associated infections.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jconrel.2024.01.061}, pmid = {38295992}, issn = {1873-4995}, abstract = {Biofilms are key players in the pathogenesis of most of chronic infections associated with host tissue or fluids and indwelling medical devices. These chronic infections are hard to be treated due to the increased biofilms tolerance towards antibiotics in comparison to planktonic (or free living) cells. Despite the advanced understanding of their formation and physiology, biofilms continue to be a challenge and there is no standardized therapeutic approach in clinical practice to eradicate them. Aptamers offer distinctive properties, including excellent affinity, selectivity, stability, making them valuable tools for therapeutic purposes. This review explores the flexibility and designability of aptamers as antibiofilm drugs but, importantly, as targeting tools for diverse drug and delivery systems. It highlights specific examples of application of aptamers in biofilms of diverse species according to different modes of action including inhibition of motility and adhesion, blocking of quorum sensing molecules, and dispersal of biofilm-cells to planktonic state. Moreover, it discusses the limitations and challenges that impaired an increased success of the use of aptamers on biofilm management, as well as the opportunities related to aptamers modifications that can significantly expand their applicability on the biofilm field.}, } @article {pmid38295957, year = {2024}, author = {Zhang, Q and Liu, H and Liang, S and Chen, W and Tan, S and Yang, C and Qin, S and Long, K}, title = {Comparison of moving bed biofilm reactor and bio-contact oxidation reactor start-up with heterotrophic nitrification-aerobic denitrification bacteria and activated sludge inoculation under high ammonia nitrogen conditions.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130408}, doi = {10.1016/j.biortech.2024.130408}, pmid = {38295957}, issn = {1873-2976}, abstract = {To overcome poor ammonia tolerance and removal performance of bio-contact oxidation (BCO) reactor inoculated with activated sludge for high-ammonia nitrogen (NH + 4-N) chemical wastewater treatment, this study compared inoculating heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria in moving bed biofilm reactor (MBBR) with activated sludge inoculation in BCO reactor under simulated high NH + 4-N conditions. Results revealed that MBBR achieved faster biofilm formation (20 days vs. 100 days for BCO) with notable advantages: 27.6 % higher total nitrogen (TN) and 29.9 % higher NH + 4-N removal efficiency than BCO. Microbial analysis indicated optimal enrichment of the key nitrogen removal (NR) bacterium Alcaligenes, leading to increased expression of NR enzymes hydroxylamine reductase, ensuring the superior NR efficiency of the MBBR. Additionally, functional enzymes and genes analysis speculated that the NR pathway in MBBR was: NH + 4-N → NH2OH → NO - 3-N → NO - 2-N → NO → N2O → N2. This research offers a practical and theoretical foundation for extending HN-AD bacteria-inoculated MBBR processes.}, } @article {pmid38295695, year = {2024}, author = {Li, Y and Gong, JY and Wang, P and Fu, H and Yousef, F and Xie, R and Wang, W and Liu, Z and Pan, DW and Ju, XJ and Chu, LY}, title = {Dissolving microneedle system containing Ag nanoparticle-decorated silk fibroin microspheres and antibiotics for synergistic therapy of bacterial biofilm infection.}, journal = {Journal of colloid and interface science}, volume = {661}, number = {}, pages = {123-138}, doi = {10.1016/j.jcis.2024.01.147}, pmid = {38295695}, issn = {1095-7103}, abstract = {Most cases of delayed wound healing are associated with bacterial biofilm infections due to high antibiotic resistance. To improve patient compliance and recovery rates, it is critical to develop minimally invasive and efficient methods to eliminate bacterial biofilms as an alternative to clinical debridement techniques. Herein, we develop a dissolving microneedle system containing Ag nanoparticles (AgNPs)-decorated silk fibroin microspheres (SFM-AgNPs) and antibiotics for synergistic treatment of bacterial biofilm infection. Silk fibroin microspheres (SFM) are controllably prepared in an incompatible system formed by a mixture of protein and carbohydrate solutions by using a mild all-aqueous phase method and serve as biological templates for the synthesis of AgNPs. The SFM-AgNPs exert dose- and time-dependent broad-spectrum antibacterial effects by inducing bacterial adhesion. The combination of SFM-AgNPs with antibiotics breaks the limitation of the antibacterial spectrum and achieves better efficacy with reduced antibiotic dosage. Using hyaluronic acid (HA) as the soluble matrix, the microneedle system containing SFM-AgNPs and anti-Gram-positive coccus drug (Mupirocin) inserts into the bacterial biofilms with sufficient strength, thereby effectively delivering the antibacterial agents and realizing good antibiofilm effect on Staphylococcus aureus-infected wounds. This work demonstrates the great potential for the development of novel therapeutic systems for eradicating bacterial biofilm infections.}, } @article {pmid38295002, year = {2024}, author = {Liu, X and Guo, X and Su, X and Ji, B and Chang, Y and Huang, Q and Zhang, Y and Wang, X and Wang, P}, title = {Extracellular Vehicles from Commensal Skin Malassezia restricta Inhibit Staphylococcus aureus Proliferation and Biofilm Formation.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00511}, pmid = {38295002}, issn = {2373-8227}, abstract = {The colonizing microbiota on the body surface play a crucial role in barrier function. Staphylococcus aureus (S. aureus) is a significant contributor to skin infection, and the utilization of colonization resistance of skin commensal microorganisms to counteract the invasion of pathogens is a viable approach. However, most studies on colonization resistance have focused on skin bacteria, with limited research on the resistance of skin fungal communities to pathogenic bacteria. Extracellular vehicles (EVs) play an important role in the colonization of microbial niches and the interaction between distinct strains. This paper explores the impact of Malassezia restricta (M. restricta), the fungus that dominates the normal healthy skin microbiota, on the proliferation of S. aureus by examining the distribution disparities between the two microorganisms. Based on the extraction of EVs, the bacterial growth curve, and biofilm formation, it was determined that the EVs of M. restricta effectively suppressed the growth and biofilm formation of S. aureus. The presence of diverse metabolites was identified as the primary factor responsible for the growth inhibition of S. aureus, specifically in relation to glycerol phospholipid metabolism, ABC transport, and arginine synthesis. These findings offer valuable experimental evidence for understanding microbial symbiosis and interactions within healthy skin.}, } @article {pmid38294883, year = {2024}, author = {Hansson, A and Karlsen, EA and Stensen, W and Svendsen, JSM and Berglin, M and Lundgren, A}, title = {Preventing E. coli Biofilm Formation with Antimicrobial Peptide-Functionalized Surface Coatings: Recognizing the Dependence on the Bacterial Binding Mode Using Live-Cell Microscopy.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c16004}, pmid = {38294883}, issn = {1944-8252}, abstract = {Antimicrobial peptides (AMPs) can kill bacteria by destabilizing their membranes, yet translating these molecules' properties into a covalently attached antibacterial coating is challenging. Rational design efforts are obstructed by the fact that standard microbiology methods are ill-designed for the evaluation of coatings, disclosing few details about why grafted AMPs function or do not function. It is particularly difficult to distinguish the influence of the AMP's molecular structure from other factors controlling the total exposure, including which type of bonds are formed between bacteria and the coating and how persistent these contacts are. Here, we combine label-free live-cell microscopy, microfluidics, and automated image analysis to study the response of surface-bound Escherichia coli challenged by the same small AMP either in solution or grafted to the surface through click chemistry. Initially after binding, the grafted AMPs inhibited bacterial growth more efficiently than did AMPs in solution. Yet, after 1 h, E. coli on the coated surfaces increased their expression of type-1 fimbriae, leading to a change in their binding mode, which diminished the coating's impact. The wealth of information obtained from continuously monitoring the growth, shape, and movements of single bacterial cells allowed us to elucidate and quantify the different factors determining the antibacterial efficacy of the grafted AMPs. We expect this approach to aid the design of elaborate antibacterial material coatings working by specific and selective actions, not limited to contact-killing. This technology is needed to support health care and food production in the postantibiotic era.}, } @article {pmid38293214, year = {2024}, author = {Banerjee, A and Kang, CY and An, M and Koff, BB and Sunder, S and Kumar, A and Tenuta, LMA and Stockbridge, RB}, title = {Fluoride export is required for competitive fitness of pathogenic microorganisms in dental biofilm models.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2024.01.18.576223}, pmid = {38293214}, abstract = {UNLABELLED: Microorganisms resist fluoride toxicity using fluoride export proteins from one of several different molecular families. Cariogenic species Streptococcus mutans and Candida albicans extrude intracellular fluoride using a CLC [F] F [-] /H [+] antiporter and FEX fluoride channel, respectively, whereas commensal eubacteria, such as Streptococcus gordonii, export fluoride using a Fluc fluoride channel. In this work, we examine how genetic knockout of fluoride export impacts pathogen fitness in single-species and three-species dental biofilm models. For biofilms generated using S. mutans with genetic knockout of the CLC [F] transporter, exposure to low fluoride concentrations decreased S. mutans counts, synergistically reduced the populations of C. albicans , increased the relative proportion of commensal S. gordonii , and reduced properties associated with biofilm pathogenicity, including acid production and hydroxyapatite dissolution. Biofilms prepared with C. albicans with genetic knockout of the FEX channel also exhibited reduced fitness in the presence of fluoride, but to a lesser degree. Imaging studies indicate that S. mutans is highly sensitive to fluoride, with the knockout strain undergoing complete lysis when exposed to low fluoride for a moderate amount of time, and biochemical purification the S. mutans CLC [F] transporter and functional reconstitution establishes that the functional protein is a dimer encoded by a single gene. Together, these findings suggest that fluoride export by oral pathogens can be targeted by specific inhibitors to restore biofilm symbiosis in dental biofilms, and that S. mutans is especially susceptible to fluoride toxicity.

IMPORTANCE: Dental caries is a globally prevalent condition that occurs when pathogenic species, including Streptococcus mutans and Candida albicans , outcompete beneficial species, such as Streptococcus gordonii, in the dental biofilm. Fluoride is routinely used in oral hygiene to prevent dental caries. Fluoride also has antimicrobial properties, although most microbes possess fluoride exporters to resist its toxicity. This work shows that sensitization of cariogenic species Streptococcus mutans and Candida albicans to fluoride by genetic knockout of fluoride exporters alters the microbial composition and pathogenic properties of dental biofilms. These results suggest that the development of drugs that inhibit fluoride exporters could potentiate the anticaries effect of fluoride in over-the-counter products like toothpastes and mouth rinses. This is a novel strategy to treat dental caries.}, } @article {pmid38292367, year = {2023}, author = {Gupta, R and Sharma, D and Mathur, M and Pooja, B and Bishnoi, R}, title = {Antibacterial activity of root canal sealers against established monospecies biofilm: An in vitro study.}, journal = {Journal of conservative dentistry and endodontics}, volume = {26}, number = {5}, pages = {569-573}, doi = {10.4103/JCDE.JCDE_37_23}, pmid = {38292367}, issn = {2950-4708}, abstract = {Endodontic treatment is primarily a combination of chemical as well as mechanical preparation of canal space which helps in the placement of a biocompatible material. The main purpose of endodontic treatment is to eradicate microorganisms from the infected root canal system and prevent recontamination. The principle constituents of an endodontic filling are core material "Gutta Percha" and "Endodontic Sealers." Endodontic sealers should ideally eliminate residual bacteria and prevent reinfection after chemomechanical treatment and obturation of the root canal. The aim of this study is to investigate the antimicrobial effect of four endodontic sealers against bacteria in biofilms commonly detected from persistent and secondary endodontic infections.}, } @article {pmid38292330, year = {2024}, author = {Deng, W and Zhou, C and Qin, J and Jiang, Y and Li, D and Tang, X and Luo, J and Kong, J and Wang, K}, title = {Molecular mechanisms of DNase inhibition of early biofilm formation Pseudomonas aeruginosa or Staphylococcus aureus: A transcriptome analysis.}, journal = {Biofilm}, volume = {7}, number = {}, pages = {100174}, doi = {10.1016/j.bioflm.2023.100174}, pmid = {38292330}, issn = {2590-2075}, abstract = {In vitro studies show that DNase can inhibit Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. However, the underlying molecular mechanisms remain poorly understood. This study used an RNA-sequencing transcriptomic approach to investigate the mechanism by which DNase I inhibits early P. aeruginosa and S. aureus biofilm formation on a transcriptional level, respectively. A total of 1171 differentially expressed genes (DEGs) in P. aeruginosa and 1016 DEGs in S. aureus enriched in a variety of biological processes and pathways were identified, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the DEGs were primarily involved in P. aeruginosa two-component system, biofilm formation, and flagellar assembly and in S. aureus biosynthesis of secondary metabolites, microbial metabolism in diverse environments, and biosynthesis of amino acids, respectively. The transcriptional data were validated using quantitative real-time polymerase chain reaction (RT-qPCR), and the expression profiles of 22 major genes remained consistent. These findings suggested that DNase I may inhibit early biofilm formation by downregulating the expression of P. aeruginosa genes associated with flagellar assembly and the type VI secretion system, and by downregulating S. aureus capsular polysaccharide and amino acids metabolism gene expression, respectively. This study offers insights into the mechanisms of DNase treatment-based inhibition of early P. aeruginosa and S. aureus biofilm formation.}, } @article {pmid38288645, year = {2024}, author = {Miescher, I and Rieber, J and Schweizer, TA and Orlietti, M and Tarnutzer, A and Andreoni, F and Meier Buergisser, G and Giovanoli, P and Calcagni, M and Snedeker, JG and Zinkernagel, AS and Buschmann, J}, title = {In Vitro Assessment of Bacterial Adhesion and Biofilm Formation on Novel Bioactive, Biodegradable Electrospun Fiber Meshes Intended to Support Tendon Rupture Repair.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c15710}, pmid = {38288645}, issn = {1944-8252}, abstract = {The surgical repair of a ruptured tendon faces two major problems: specifically increased fibrous adhesion to the surrounding tissue and inferior mechanical properties of the scar tissue compared to the native tissue. Bacterial attachment to implant materials is an additional problem as it might lead to severe infections and impaired recovery. To counteract adhesion formation, two novel implant materials were fabricated by electrospinning, namely, a random fiber mesh containing hyaluronic acid (HA) and poly(ethylene oxide) (PEO) in a ratio of 1:1 (HA/PEO 1:1) and 1:4 (HA/PEO 1:4), respectively. Electrospun DegraPol (DP) treated with silver nanoparticles (DP-Ag) was developed to counteract the bacterial attachment. The three novel materials were compared to the previously described DP and DP with incorporated insulin-like growth factor-1 (DP-IGF-1), two implant materials that were also designed to improve tendon repair. To test whether the materials are prone to bacterial adhesion and biofilm formation, we assessed 10 strains of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Enterococcus faecalis, known for causing nosocomial infections. Fiber diameter, pore size, and water contact angle, reflecting different degrees of hydrophobicity, were used to characterize all materials. Generally, we observed higher biofilm formation on the more hydrophobic DP as compared to the more hydrophilic DP-IGF-1 and a trend toward reduced biofilm formation for DP treated with silver nanoparticles. For the two HA/PEO implants, a similar biofilm formation was observed. All tested materials were highly prone to bacterial adherence and biofilm formation, pointing toward the need of further material development, including the optimized incorporation of antibacterial agents such as silver nanoparticles or antibiotics.}, } @article {pmid38288293, year = {2024}, author = {Reichardt, E and Shyp, V and Alig, L and Verna, C and Kulik, EM and Bornstein, MM}, title = {Antimicrobial effect of probiotic bacteriocins on Streptococcus mutans biofilm in a dynamic oral flow chamber model - an in vitro study.}, journal = {Journal of oral microbiology}, volume = {16}, number = {1}, pages = {2304971}, pmid = {38288293}, issn = {2000-2297}, abstract = {AIM: To determine the antimicrobial activity of the bacteriocin-producing probiotic strains Streptococcus salivarius K12 and Streptococcus salivarius M18 alone or in combination against caries-associated Streptococcus mutans.

METHODS: Antimicrobial activity of S. salivarius K12 and/or S. salivarius M18 against S. mutans ATCC 25175 growth and biofilm formation on hydroxyapatite (HA) discs was determined in a flow chamber model by recording the colony forming units (CFU/ml) after 48 h of co-cultivation. The biofilm was analyzed by scanning electron microscopy (SEM) and by confocal laser scanning microscopy (CLSM). Additionally, the simultaneous antagonism assay was used to assess the inhibitory effect of S. salivarius K12 and/or S. salivarius M18 against S. mutans ATCC 25175 and 21 clinical isolates of S. mutans.

RESULTS: Co-cultivation of S. mutans and S. salivarius K12 and/or S. salivarius M18 led to the inhibition of S. mutans viability, thereby, preventing its biofilm formation on HA discs. Furthermore, S. salivarius K12 and S. salivarius M18 exhibited antimicrobial activity against most clinical isolates of S. mutans.

CONCLUSION: The in vitro flow chamber system used in this study allows the simulation of time-dependent administration of S. salivarius probiotic strains, either alone or in combination, to investigate the prevention of S. mutans biofilm formation in a standardized model.}, } @article {pmid38287229, year = {2024}, author = {Mendez-Pfeiffer, P and Ballesteros-Monrreal, MG and Juarez, J and Gastelum-Cabrera, M and Martinez-Flores, P and Taboada, P and Valencia, D}, title = {Chitosan-Coated Silver Nanoparticles Inhibit Adherence and Biofilm Formation of Uropathogenic Escherichia coli.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00229}, pmid = {38287229}, issn = {2373-8227}, abstract = {Urinary tract infections are commonly caused by uropathogenic Escherichia coli (UPEC), which usually presents multiple virulence and resistance mechanisms, making it difficult to treat. It has been demonstrated that silver and polymeric nanoparticles had potential against these pathogens. In this study, we synthesized thiol chitosan-coated silver nanoparticles (SH-Cs-AgNPs) and evaluated their antibacterial, antibiofilm and antiadherence activity against clinical isolates of UPEC. The SH-Cs-AgNPs showed a spherical shape with a size of 17.80 ± 2.67 nm and zeta potential of 18 ± 2 mV. We observed a potent antibacterial and antibiofilm activity as low as 12.5 μg/mL, as well as a reduction in the adherence of UPEC to mammalian cells at concentrations of 1.06 and 0.53 μg/mL. These findings demonstrate that SH-Cs-AgNPs have potential as a new therapeutic compound against infections caused by UPEC.}, } @article {pmid38286789, year = {2024}, author = {Khosakueng, M and Taweechaisupapong, S and Boonyanugomol, W and Prapatpong, P and Wongkaewkhiaw, S and Kanthawong, S}, title = {Cymbopogon citratus L. essential oil as a potential anti-biofilm agent active against antibiotic-resistant bacteria isolated from chronic rhinosinusitis patients.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/08927014.2024.2305387}, pmid = {38286789}, issn = {1029-2454}, abstract = {Chronic rhinosinusitis (CRS) is long-term inflammation of the sinuses that can be caused by infection due to antibiotic-resistant bacteria. Biofilm developed by microbes is postulated to cause antibiotic treatment failure. Thus, the anti-biofilm activities of seven Thai herbal essential oils (EOs) against antibiotic-resistant bacteria isolated from CRS patients was investigated. Lemongrass (Cymbopogon citratus L.) EO showed the most effective antibiofilm activity against Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus epidermidis grown as biofilm. GC-MS analysis found that myrcene was the major bioactive compound. Pretreatment with lemongrass EO significantly inhibited biofilm formation of all bacterial strains in more than 50% of cases. Furthermore, confocal microscopy analysis revealed the biofilm-disrupting activity of lemongrass EO against the biofilm matrix of all these bacterial species and also increased P. aeruginosa swarming motility with no toxicity to human cells. These results suggest that lemongrass EO has promising clinical applications as an anti-biofilm agent for CRS patients.}, } @article {pmid38286744, year = {2024}, author = {Chukamnerd, A and Saipetch, N and Singkhamanan, K and Ingviya, N and Assanangkornchai, N and Surachat, K and Chusri, S}, title = {Association of biofilm formation, antimicrobial resistance, clinical characteristics, and clinical outcomes among Acinetobacter baumannii isolates from patients with ventilator-associated pneumonia.}, journal = {The clinical respiratory journal}, volume = {18}, number = {1}, pages = {e13732}, doi = {10.1111/crj.13732}, pmid = {38286744}, issn = {1752-699X}, support = {//Faculty of Medicine, Prince of Songkla University/ ; //Postdoctoral Fellowship from Prince of Songkla University, Thailand/ ; }, abstract = {INTRODUCTION: Biofilm formation is an important virulence factor of Acinetobacter baumannii. Here, we examined the biofilm formation of archived A. baumannii causing ventilator-associated pneumonia (VAP).

METHODS: Eighteen and twenty isolates of A. baumannii causing bacteremic pneumonia and non-bacteremic pneumonia were included, respectively. Antimicrobial susceptibility testing was performed by broth microdilution method, while biofilm formation was evaluated by microtiter dish biofilm formation assay.

RESULTS: All 38 isolates were still susceptible to colistin and tigecycline, whereas almost all isolates were non-susceptible (intermediate to resistant) to several antimicrobial agents, especially ceftriaxone and cefotaxime. Approximately, 44% of bacteremic isolates and 50% of non-bacteremic isolates were classified as carbapenem-resistant A. baumannii (CRAB). Biofilm formation was detected in 42% of the studied isolates. Bacteremia among the patients infected with biofilm-producing isolates was significantly higher than in those infected with non-biofilm-producing isolates. The antimicrobial susceptibilities of A. baumannii with biofilm formation were lower than those without biofilm formation, but the differences did not have statistical significance. The patients infected with non-biofilm-producing isolates had good clinical and non-clinical outcomes than those infected with biofilm-producing isolates. The survival rate of patients diagnosed with VAP due to biofilm-producing A. baumannii was lower than in those patients diagnosed with VAP due to non-biofilm-producing isolates.

CONCLUSION: Biofilm formation of A. baumannii causing VAP was associated with antimicrobial resistance and bacteremia as well as unfavorable clinical outcomes.}, } @article {pmid38286383, year = {2024}, author = {Raj, V and Raorane, CJ and Shastri, D and Kim, SC and Lee, S}, title = {Engineering a self-healing grafted chitosan-sodium alginate based hydrogel with potential keratinocyte cell migration property and inhibitory effect against fluconazole resistance Candida albicans biofilm.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {129774}, doi = {10.1016/j.ijbiomac.2024.129774}, pmid = {38286383}, issn = {1879-0003}, abstract = {Biofilms developed by microorganisms cause an extremely severe clinical problem that leads to drug failure. Bioactive polymeric hydrogels display potential for controlling the formation of microorganism-based biofilms, but their rapid biodegradability in these biofilm sites is still a major challenge. To overcome this, chitosan (CS), a natural functional biomaterial, has been used because of its effective penetrability in the cell wall of microorganisms; however, its fast biodegradability has restricted its further use. Hence, in this study, to improve the stability of CS and increase its penetration retention inside a biofilm, grafted CS was prepared and then crosslinked with sodium alginate (SA) to synthesize CS-poly(MA-co-AA)SA hydrogel via a free radical grafting method, therefore enhancing its antibiofilm efficiency against biofilms. The prepared hydrogel demonstrated excellent effectiveness against (≥90 % inhibition) biofilms of Candida albicans. Additionally, in vitro and in vivo safety assays established that the prepared hydrogel can be used in a biofilm microenvironment and might reduce drug resistance burden owing to its long-term antibiofilm effect and improved CS stability at the biofilm site. Furthermore, in vitro wound healing outcomes of hydrogel indicated its potential application for chronic wound treatment. This research opens a new advanced strategy for biofilm-associated infection treatment, including wound treatment.}, } @article {pmid38286325, year = {2024}, author = {Cao, X and Zhang, T and Tao, C and Ren, Y and Wang, X}, title = {A new method: Characterize and quantify biofilm wrinkles by UNet and Sholl Analysis.}, journal = {Bio Systems}, volume = {}, number = {}, pages = {105131}, doi = {10.1016/j.biosystems.2024.105131}, pmid = {38286325}, issn = {1872-8324}, abstract = {The wrinkles on the biofilm contain a lot of information about biofilm growth, so it is essential to characterize and quantify these wrinkles from the original microscopic images to discover more rules governing the biofilm morphology evolution. However, the existing methods to extract the wrinkles are time-consuming, error-prone, and require manual calibration. We propose a new system: using a deep learning method - UNet to identify the biofilm wrinkles in the original experimental images, which can achieve fast and accurate extraction of wrinkles on biofilms. Combining the result of UNet and medical neuron analysis method - Sholl Analysis, we can easily characterize and quantity the B. subtilis biofilm wrinkles. We proposed new characterization parameters such as wrinkle density, wrinkle length, and wrinkle projection area, which can precisely partition the biofilm surface wrinkles into different regions from the biofilm center to the edge, different regions correspond to different growth stages. Our system can be applied to study biofilms growing in different kinds of environments and to study the biofilm growth mechanisms.}, } @article {pmid38285273, year = {2024}, author = {Fernández-Torres, J and Zamudio-Cuevas, Y and Martínez-Flores, K and Franco-Cendejas, R}, title = {Relationship between biofilm-forming microorganisms (BFM: Staphylococcus aureus and Pseudomonas aeruginosa) and DEFB1 gene variants on β-defensin levels in periprosthetic joint infection (PJI).}, journal = {Molecular biology reports}, volume = {51}, number = {1}, pages = {237}, pmid = {38285273}, issn = {1573-4978}, abstract = {BACKGROUND: The purpose of this study was to investigate the relationship between biofilm-forming microorganisms (BFM) and DEFB1 gene variants on β-defensin levels in patients with periprosthetic joint infection (PJI) of Mexican origin.

METHODS AND RESULTS: One hundred and five clinical aspirates were obtained from patients with suspected PJI. After microbiologic culture, samples were classified as non-septic and septic; of the latter, only those positive for Staphylococcus aureus and Pseudomonas aeruginosa were selected. β-Defensin levels were quantified by ELISA, DNA was extracted from total leukocytes of the samples, and - 20G > A (rs11362) and - 44 C > G (rs1800972) variants were genotyped using TaqMan probes. Forty-one clinical aspirates were non-septic, 18 were positive for S. aureus and 18 were positive for P. aeruginosa. It was observed that β-defensin levels were higher in the P. aeruginosa group compared to S. aureus group (2339.0 pg/mL IQR = 1809.2 vs. 1821.3 pg/mL IQR = 1536.4) and non-septic group (2339.0 pg/mL IQR = 1809.2 vs. 1099.7 pg/mL IQR = 1744.5, P < 0.001). The CG genotype of the rs1800972 variant was associated with higher β-defensin levels compared to the CC genotype for both P. aeruginosa and S. aureus (1905.8 vs. 421.7 pg/mL, P = 0.004; and 1878.2 vs. 256.4 pg/mL, P = 0.006, respectively).

CONCLUSIONS: Our results show that β-defensin levels are significantly elevated in patients with BFM-associated PJI compared to those without infection. Furthermore, carriers of the CG genotype of the rs1800972 variant have an increased risk of PJI. Further research is needed to replicate these findings in a larger population.}, } @article {pmid38284755, year = {2024}, author = {Chen, Y and Gao, F and Chen, X and Tao, S and Chen, P and Lin, W}, title = {The basic leucine zipper transcription factor MeaB is critical for biofilm formation, cell wall integrity, and virulence in Aspergillus fumigatus.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0061923}, doi = {10.1128/msphere.00619-23}, pmid = {38284755}, issn = {2379-5042}, abstract = {The regulation of fungal cell wall biosynthesis is crucial for cell wall integrity maintenance and directly impacts fungal pathogen virulence. Although numerous genes are involved in fungal cell wall polysaccharide biosynthesis through multiple pathways, the underlying regulatory mechanism is still not fully understood. In this study, we identified and functionally characterized a direct downstream target of SomA, the basic-region leucine zipper transcription factor MeaB, playing a certain role in Aspergillus fumigatus cell wall integrity. Loss of meaB reduces hyphal growth, causes severe defects in galactosaminogalactan-mediated biofilm formation, and attenuates virulence in a Galleria mellonella infection model. Furthermore, the meaB null mutant strain exhibited hypersensitivity to cell wall-perturbing agents and significantly alters the cell wall structure. Transcriptional profile analysis revealed that MeaB positively regulates the expression of the galactosaminogalactan biosynthesis and β-1,3-glucanosyltransferase genes uge3, agd3, and sph3 and gel1, gel5, and gel7, respectively, as well as genes involved in amino sugar and nucleotide sugar metabolism. Further study demonstrated that MeaB could respond to cell wall stress and contribute to the proper expression of mitogen-activated protein kinase genes mpkA and mpkC in the presence of different concentrations of congo red. In conclusion, A. fumigatus MeaB plays a critical role in cell wall integrity by governing the expression of genes encoding cell wall-related proteins, thus impacting the virulence of this fungus.IMPORTANCEAspergillus fumigatus is a common opportunistic mold that causes life-threatening infections in immunosuppressed patients. The fungal cell wall is a complex and dynamic organelle essential for the development of pathogenic fungi. Genes involved in cell wall polysaccharide biosynthesis and remodeling are crucial for fungal pathogen virulence. However, the potential regulatory mechanism for cell wall integrity remains to be fully defined in A. fumigatus. In the present study, we identify basic-region leucine zipper transcription factor MeaB as an important regulator of cell wall galactosaminogalactan biosynthesis and β-1,3-glucan remodeling that consequently impacts stress response and virulence of fungal pathogens. Thus, we illuminate a mechanism of transcriptional control fungal cell wall polysaccharide biosynthesis and stress response. As these cell wall components are promising therapeutic targets for fungal infections, understanding the regulatory mechanism of such polysaccharides will provide new therapeutic opportunities.}, } @article {pmid38282617, year = {2023}, author = {Abd El-Hamid, MI and Ibrahim, D and Elazab, ST and Gad, WM and Shalaby, M and El-Neshwy, WM and Alshahrani, MA and Saif, A and Algendy, RM and AlHarbi, M and Saleh, FM and Alharthi, A and Mohamed, EAA}, title = {Tackling strong biofilm and multi-virulent vancomycin-resistant Staphylococcus aureus via natural alkaloid-based porous nanoparticles: perspective towards near future eradication.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1287426}, doi = {10.3389/fcimb.2023.1287426}, pmid = {38282617}, issn = {2235-2988}, abstract = {INTRODUCTION: As a growing direction, nano-based therapy has become a successful paradigm used to address the phytogenic delivery-related problems in overcoming multivirulent vancomycin-resistant Staphylococcus aureus (VRSA) infection.

METHODS: Hence, our aim was to develop and assess a novel nanocarrier system (mesoporous silica nanoparticles, MPS-NPs) for free berberine (Free-BR) as an antimicrobial alkaloid against strong biofilm-producing and multi-virulent VRSA strains using in vitro and in vivo mouse model.

RESULTS AND DISCUSSION: Our outcomes demonstrated vancomycin resistance in 13.7% of Staphylococcus aureus (S. aureus) strains categorized as VRSA. Notably, strong biofilm formation was observed in 69.2% of VRSA strains that were all positive for icaA gene. All strong biofilm-producing VRSA strains harbored a minimum of two virulence genes comprising clfA and icaA with 44.4% of them possessing all five virulence genes (icaA, tst, clfA, hla, and pvl), and 88.9% being multi-virulent. The study findings affirmed excellent in vitro antimicrobial and antibiofilm properties of BR-loaded MPS-NPs. Real-time quantitative reverse transcription PCR (qRT-PCR) assay displayed the downregulating role of BR-loaded MPS-NPs on strong biofilm-producing and multi-virulent VRSA strains virulence and agr genes in both in vitro and in vivo mice models. Additionally, BR-loaded MPS-NPs supplementation has a promising role in attenuating the upregulated expression of pro-inflammatory cytokines' genes in VRSA-infected mice with attenuation in pro-apoptotic genes expression resulting in reduced VRSA-induced apoptosis. In essence, the current study recommends the future scope of using BR-loaded MPS-NPs as auspicious alternatives for antimicrobials with tremendous antimicrobial, antibiofilm, anti-quorum sensing (QS), and anti-virulence effectiveness against problematic strong biofilm-producing and multi-virulent VRSA-associated infections.}, } @article {pmid38282327, year = {2024}, author = {Astrada, A and Pamungkas, RA and Abidin, KR}, title = {Advancements in Managing Wound Biofilm: A Systematic Review and Meta-analysis of Randomized Controlled Trials on Topical Modalities.}, journal = {Foot & ankle specialist}, volume = {}, number = {}, pages = {19386400231225708}, doi = {10.1177/19386400231225708}, pmid = {38282327}, issn = {1938-7636}, abstract = {Despite numerous available agents claiming anti-biofilm properties on wounds, the substantiating evidence remains inconclusive. This study aimed to assess the immediate impact of topical wound treatments on wound biofilm and healing outcomes in acute and chronic ulcers. We comprehensively searched PubMed, ClinicalTrials.gov, and Google Scholar. In addition, eligible gray literature was incorporated. English-language randomized controlled trials (RCTs), observational, cohort, and case-control studies targeting biofilm prevention, inhibition, or elimination across diverse wound types were included. Primary outcomes included biofilm presence and elimination, supplemented by secondary outcomes encompassing reduced wound size, complete closure, and diminished infection indicators. Bacterial load reduction and biofilm presence were also assessed. Twenty-eight articles met the inclusion criteria. Various modalities were identified, including biofilm-visualization techniques, such as wound blotting and handheld autofluorescence imaging. Pooled analysis for the primary outcomes was infeasible due to limited eligible studies and data-reporting challenges. As for the secondary outcomes, the pooled analysis for complete surgical wound closure (2 RCTs, yielding n=284) and presence of surgical site infections/inflammation (2 RCTs, yielding n=284) showed no significant difference, with a log odds ratio (LOD) of 0.58 (95% confidence interval [CI]: -.33, 1.50) and LOD -0.95 (95% CI: -3.54, 1.64; τ[2] = 2.32, Q = 2.71, P = .10), respectively. Our findings suggest insufficient evidence to support anti-biofilm claims of topical modalities. Clinicians' skill appears to play a pivotal role in biofilm elimination and wound healing enhancement, with potential optimization through visual-guided techniques, such as wound blotting and autofluorescence imaging. More rigorous clinical trials are warranted to ascertain the efficacy of these techniques.Level of Evidence: Therapeutic, 1A.}, } @article {pmid38281545, year = {2024}, author = {Xu, Y and Wei, C and Liu, D and Li, J and Tian, B and Li, Z and Xu, L}, title = {Life-cycle and economic assessments of microalgae biogas production in suspension and biofilm cultivation systems.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130381}, doi = {10.1016/j.biortech.2024.130381}, pmid = {38281545}, issn = {1873-2976}, abstract = {Biogas production via anaerobic digestion is highly attractive for microalgae. The technology of microalgae cultivation has profound impacts on biogas production system as it is the most energy-consuming process. However, a comprehensive evaluation of the environmental and economic benefits of different cultivation systems has yet to be sufficiently conducted. Here, life-cycle and economic assessments of open raceway ponds, photobioreactors and biofilm systems were investigated. Results showed greenhouse gas emissions of all systems were positive because more than two-thirds of carbon in fuel gas was lost and the fixed carbon in product gas and solid fertilizer was less than the emitted carbon during energy input. Particularly, biofilm system achieved the least greenhouse gas emissions (9.3 g CO2-eq/MJ), net energy ratio (0.7) and levelized cost of energy (0.9 $/kWh), indicating the optimum cultivation system. Open raceway ponds and photobioreactors failed to achieve positive benefits because of low harvesting efficiency and biomass concentration.}, } @article {pmid38281390, year = {2024}, author = {Vendrell-Puigmitja, L and Bertrans-Tubau, L and Roca-Ayats, M and Llenas, L and Proia, L and Abril, M}, title = {Exposure and recovery: The effect of different dilution factors of treated and untreated metal mining effluent on freshwater biofilm function and structure.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {268}, number = {}, pages = {106843}, doi = {10.1016/j.aquatox.2024.106843}, pmid = {38281390}, issn = {1879-1514}, abstract = {Abandoned mines generate effluents rich in heavy metals, and these contaminants are released uncontrolled into the nearby aquatic ecosystems, causing severe pollution. However, no real solution exists, leaving a legacy of global pollution. In this study, the efficiency of the treatment technologies in reducing the ecological impacts of mining effluents to freshwater ecosystems with different dilution capacities was tested using biofilm communities as biological indicators. The functional and structural recovery capacity of biofilm communities after 21 days of exposure was assessed. With this aim, we sampled aquatic biofilms from a pristine stream and exposed them to treated (T) and untreated (U) metal mining effluent from Frongoch abandoned mine (Mid Wales, UK). Additionally, we simulated two different flow conditions for the receiving stream: high dilution (HD) and low dilution (LD). After exposure, the artificial streams were filled with artificial water for 14 days to assess the biofilm recovery. Unexposed biofilm served as control for biofilm responses (functional and structural) measured throughout time. During the exposure, short term effects on biofilm functioning (photosynthetic efficiency, nutrient uptake) were observed in T-LD, U-HD, and U-LD, whereas long term effects (community composition, chl-a, and diatom metrics) were observed on the structure of all biofilms exposed to the treated and untreated mining effluent. On the other hand, metal accumulation occurred in biofilms exposed to the mining effluents. However, a functional recovery was observed for all treatments, except in the U-LD in which biofilm structure did not present a significant recovery after the exposure period. The results presented here highlight the need to consider the dilution capacity of the receiving stream to assess the real efficiency of treatment technologies applied to mining effluents to mitigate the ecological impact on freshwater ecosystems.}, } @article {pmid38281366, year = {2024}, author = {Jin, Y and Wang, D and Zhang, D and Gao, Y and Xu, D and Wang, F}, title = {Harnessing active biofilm for microbial corrosion protection of carbon steel against Geobacter sulfurreducens.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {157}, number = {}, pages = {108654}, doi = {10.1016/j.bioelechem.2024.108654}, pmid = {38281366}, issn = {1878-562X}, abstract = {Microbiologically influenced corrosion (MIC) caused by corrosive microorganisms poses significant economic losses and safety hazards. Conventional corrosion prevention methods have limitations, so it is necessary to develop the eco-friendly and long-term effective strategies to mitigate MIC. This study investigated the inhibition of Vibrio sp. EF187016 biofilm on Geobacter sulfurreducens on carbon steel. Vibrio sp. EF187016 biofilm reduced the corrosion current density and impeded pitting corrosion. A thick and uniform Vibrio sp. EF187016 biofilm formed on the coupon surfaces, acting as a protective layer against corrosive ions and electron acquisition by G. sulfurreducens. The pre-grown mature Vibrio sp. EF187016 biofilms, provided enhanced protection against G. sulfurreducens corrosion. Additionally, the extracellular polymeric substances from Vibrio sp. EF187016 was confirmed to act as a green corrosion inhibitor to mitigate microbial corrosion. This study highlights the potential of active biofilms for eco-friendly corrosion protection, offering a novel perspective on material preservation against microbial corrosion.}, } @article {pmid38280935, year = {2024}, author = {Maktabi, S and Rashnavadi, R and Tabandeh, MR and Sourestani, MM}, title = {Effective Inhibition of Listeria monocytogenes Biofilm Formation by Satureja rechingeri Essential Oil: Mechanisms and Implications.}, journal = {Current microbiology}, volume = {81}, number = {3}, pages = {77}, pmid = {38280935}, issn = {1432-0991}, support = {SCU.VF1400.534//Shahid Chamran University of Ahvaz/ ; }, abstract = {Biofilm formation by foodborne pathogens, particularly Listeria monocytogenes, poses a significant challenge in food industry facilities. In this study, we investigated the inhibitory potential of Satureja rechingeri essential oil (Sr-EO) against L. monocytogenes growth and biofilm formation. Gas chromatography-mass spectrometry analysis revealed a high carvacrol content in Sr-EO, a compound with known antimicrobial properties. We examined the effects of Sr-EO on initial attachment and preformed biofilms, using crystal violet and MTT assays to quantify attached biomass and metabolic activity, respectively. Our results demonstrated that Sr-EO not only prevented initial attachment but also effectively disrupted preformed biofilms, indicating its potential as a biofilm-control agent. Microscopy analysis revealed alterations in bacterial cell membranes upon Sr-EO treatment, leading to increased permeability and cell death. Additionally, Sr-EO significantly suppressed bacterial motility, with concentrations exceeding 0.25 μL/mL completely inhibiting motility. Furthermore, gene expression analysis revealed the down regulation of genes associated with biofilm formation, attachment, and quorum sensing, suggesting that Sr-EO modulates bacterial gene transcription. These findings suggest that Sr-EO can be a promising candidate for controlling biofilm formation and bacterial contamination in food processing environments.}, } @article {pmid38280925, year = {2024}, author = {El-Sawy, YNA and Abdel-Salam, AB and Abd-Elhady, HM and Abou-Taleb, KAA and Ahmed, RF}, title = {Elimination of detached Listeria monocytogenes from the biofilm on stainless steel surfaces during milk and cheese processing using natural plant extracts.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {2288}, pmid = {38280925}, issn = {2045-2322}, abstract = {Bacterial cells can form biofilm on food contact surfaces, becoming a source of food contamination with profound health implications. The current study aimed to determine some Egyptian medicinal plants antibacterial and antibiofilm effects against foodborne bacterial strains in milk plants. Results indicated that four ethanolic plant extracts, Cinnamon (Cinnamomum verum), Chamomile (Matricaria chamomilla), Marigold (Calendula officinalis), and Sage (Salvia officinalis), had antibacterial (12.0-26.5 mm of inhibition zone diameter) and antibiofilm (10-99%) activities against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella Typhimurium. The tested extracts had minimum inhibitory concentration values between 0.14 and 2.50 mg/ml and minimum bactericidal concentration values between 0.14 and 12.50 mg/ml. L. monocytogenes was more sensitive for all tested ethanolic extracts; Sage and Cinnamon showed a bacteriocidal effect, while Chamomile and Marigold were bacteriostatic. The ethanolic extracts mixture from Chamomile, Sage, and Cinnamon was chosen for its antibiofilm activity against L. monocytogenes using L-optimal mixture design. Gas chromatography and mass spectrometry analysis showed that this mixture contained 12 chemical compounds, where 2-Propenal,3-phenyl- had the maximum area % (34.82%). At concentrations up to 500 µg/ml, it had no cytotoxicity in the normal Vero cell line, and the IC50 value was 671.76 ± 9.03 µg/ml. Also, this mixture showed the most significant antibacterial effect against detached L. monocytogenes cells from formed biofilm in stainless steel milk tanks. At the same time, white soft cheese fortified with this mixture was significantly accepted overall for the panelist (92.2 ± 2.7) than other cheese samples, including the control group.}, } @article {pmid38280544, year = {2024}, author = {Walker, N and White, SM and Ruiz, SA and McKay Fletcher, D and Saponari, M and Roose, T}, title = {A mathematical model of biofilm growth and spread within plant xylem: Case study of Xylella fastidiosa in olive trees.}, journal = {Journal of theoretical biology}, volume = {}, number = {}, pages = {111737}, doi = {10.1016/j.jtbi.2024.111737}, pmid = {38280544}, issn = {1095-8541}, abstract = {Xylem-limited bacterial pathogens cause some of the most destructive plant diseases. Though imposed measures to control these pathogens are generally ineffective, even among susceptible taxa, some hosts can limit bacterial loads and symptom expression. Mechanisms by which this resistance is achieved are poorly understood. In particular, it is still unknown how differences in vascular structure may influence biofilm growth and spread within a host. To address this, we developed a novel theoretical framework to describe biofilm behaviour within xylem vessels, adopting a polymer-based modelling approach. We then parameterised the model to investigate the relevance of xylem vessel diameters on Xylella fastidiosa resistance among olive cultivars. The functionality of all vessels was severely reduced under infection, with hydraulic flow reductions of 2-3 orders of magnitude. However, results suggest wider vessels act as biofilm incubators; allowing biofilms to develop over a long time while still transporting them through the vasculature. By contrast, thinner vessels become blocked much earlier, limiting biofilm spread. Using experimental data on vessel diameter distributions, we were able to determine that a mechanism of resistance in the olive cultivar Leccino is a relatively low abundance of the widest vessels, limiting X. fastidiosa spread.}, } @article {pmid38280528, year = {2024}, author = {Chen, G and Zhang, H and Yuan, M and Huang, R and Xiao, Y and Qu, Y and Ren, Y}, title = {Physiological responses and molecular mechanisms of biofilm formation induced by extracellular metabolites of euglena in Pseudomonas aeruginosa LNR1 for diesel biodegradation based on transcriptomic and proteomic.}, journal = {Environmental research}, volume = {}, number = {}, pages = {118273}, doi = {10.1016/j.envres.2024.118273}, pmid = {38280528}, issn = {1096-0953}, abstract = {Diesel, as a toxic and complex pollutant, is one of the main components in oily wastewater, and poses serious threats to the water environment and the health of organisms. Employing environmentally friendly biostimulants to enhance the metabolic functions of microorganisms is currently the optimal choice to improve the biodegradation of oil-containing wastewater efficiency. This study takes Pseudomonas aeruginosa LNR1 as the target, analyzing the physiological responses and molecular mechanisms of biofilm formation when enhanced by the extracellular metabolites of euglena (EME) for diesel degradation. The results show that EME not only induces auto-aggregation behavior of strain LNR1, forming aerobic suspended granule biofilm, but also promotes the secretion of signaling molecules in the quorum sensing (QS) system. Transcriptomic and proteomic analyses indicate that the stimulatory effect of EME on strain LNR1 mainly manifests in biofilm formation, substance transmembrane transport, signal transduction, and other biological processes, especially the QS system in signal transduction, which plays a significant regulatory role in biofilm formation, chemotaxis, and two-component system (TCS). This study collectively unveils the molecular mechanisms of biostimulant EME inducing strain LNR1 to enhance diesel degradation from different aspects, providing theoretical guidance for the practical application of EME in oily wastewater pollution control.}, } @article {pmid38280369, year = {2024}, author = {Jin, Y and Lin, J and Shi, H and Jin, Y and Cao, Q and Chen, Y and Zou, Y and Tang, Y and Li, Q}, title = {The active ingredients in Chinese peony pods synergize with antibiotics to inhibit MRSA growth and biofilm formation.}, journal = {Microbiological research}, volume = {281}, number = {}, pages = {127625}, doi = {10.1016/j.micres.2024.127625}, pmid = {38280369}, issn = {1618-0623}, abstract = {Staphylococcus aureus (S. aureus) is a zoonotic pathogen that infects both humans and animals. The rapid spread of methicillin-resistant S. aureus (MRSA) and its resistance to antibiotics, along with its ability to form biofilms, poses a serious challenge to the clinical application of traditional antibiotics. Peony (Paeonia lactiflora Pall.) is a traditional Chinese medicine with multiple pharmacological effects. This study observed the strong antibacterial and antibiofilm activity of the water extract (WE) and ethyl acetate extract (EA) of Chinese peony pods against MRSA. The combination of EA and vancomycin, cefotaxime, penicillin G or methicillin showed a synergistic or additive antibacterial and antibiofilm effects on MRSA, which is closely related to the interaction of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PG) and methyl gallate (MG). The active ingredients in peony pods have been found to increase the sensitivity of MRSA to antibiotics and demonstrate antibiofilm activity, which is mainly related to the down-regulation of global regulatory factors sarA and sigB, extracellular PIA and eDNA encoding genes icaA and cdiA, quorum sensing related genes agrA, luxS, rnaIII, hld, biofilm virulence genes psma and sspA, and genes encoding clotting factors coa and vwb, but is not related to genes that inhibit cell wall anchoring. In vivo test showed that both WE and EA were non-toxic and significantly prolonged the lifespan of G. mellonella larvae infected with MRSA. This study provides a theoretical basis for further exploration of the combined use of PG, MG and antibiotics to combat MRSA infections.}, } @article {pmid38280304, year = {2024}, author = {Wang, H and Fan, Q and Wang, Y and Yi, L and Wang, Y}, title = {Rethinking the control of Streptococcus suis infection: Biofilm formation.}, journal = {Veterinary microbiology}, volume = {290}, number = {}, pages = {110005}, doi = {10.1016/j.vetmic.2024.110005}, pmid = {38280304}, issn = {1873-2542}, abstract = {Streptococcus suis is an emerging zoonotic pathogen that is widespread in swine populations. The control of S. suis infection and its associated diseases is a daunting challenge worldwide. Biofilm formation appears to be the main reason for the persistence of S. suis. In this review we gather existing knowledge on S. suis biofilm, describing the role of biofilm formation in S. suis virulence and drug resistance, the regulatory factors of S. suis biofilm formation, and the research progress of inhibiting S. suis biofilm formation, with the aim of providing guidance for future studies related to the field of S. suis biofilms.}, } @article {pmid38277629, year = {2023}, author = {Snyder, RJ and Singer, AJ and Dove, CR and Heisler, S and Petusevsky, H and James, G and deLancey Pulcini, E and Yaakov, AB and Rosenberg, L and Grant, E and Shoham, Y}, title = {An open-label, proof-of-concept study assessing the effects of bromelain-based enzymatic debridement on biofilm and microbial loads in patients with venous leg ulcers and diabetic foot ulcers.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {35}, number = {12}, pages = {E414-E419}, pmid = {38277629}, issn = {1943-2704}, abstract = {BACKGROUND: Most chronic wounds contain biofilm, and debridement remains the centerpiece of treatment. Enzymatic debridement is an effective tool in removing nonviable tissue, however, there is little evidence supporting its effect on planktonic and biofilm bacteria.

OBJECTIVE: This study evaluated the effects of a novel BBD agent on removal of nonviable tissue, biofilm, and microbial loads in patients with chronic ulcers.

MATERIALS AND METHODS: Twelve patients with DFU or VLU were treated with up to 8 once-daily applications of BBD and then followed for an additional 2 weeks. Punch biopsy specimens were collected and analyzed for biofilm, and fluorescence imaging was used to measure bacterial load.

RESULTS: Ten patients completed treatment, and 7 achieved complete debridement within a median of 2 applications (range, 2-8). By the end of the 2-week follow-up period, the mean ± SD reduction in wound area was 35% ± 38. In all 6 patients who were positive for biofilm at baseline, the biofilm was reduced to single individual or no detected microorganisms by the end of treatment. Red fluorescence for Staphylococcus aureus decreased from a mean of 1.09 cm² ± 0.58 before treatment to 0.39 cm² ± 0.25 after treatment. BBD was safe and well tolerated.

CONCLUSION: Preliminary data suggest that BBD is safe and that it can be used to effectively debride DFU and VLU, reduce biofilm and planktonic bacterial load, and promote reduction in wound size.}, } @article {pmid38276176, year = {2023}, author = {Anokwah, D and Asante-Kwatia, E and Asante, J and Obeng-Mensah, D and Danquah, CA and Amponsah, IK and Ameyaw, EO and Biney, RP and Obese, E and Oberer, L and Amoako, DG and Abia, ALK and Mensah, AY}, title = {Antibacterial, Resistance Modulation, Anti-Biofilm Formation, and Efflux Pump Inhibition Properties of Loeseneriella africana (Willd.) N. Halle (Celastraceae) Stem Extract and Its Constituents.}, journal = {Microorganisms}, volume = {12}, number = {1}, pages = {}, pmid = {38276176}, issn = {2076-2607}, abstract = {This study investigated the antibacterial, resistance modulation, biofilm inhibition, and efflux pump inhibition potentials of Loeseneriella africana stem extract and its constituents. The antimicrobial activity was investigated by the high-throughput spot culture growth inhibition (HT-SPOTi) and broth microdilution assays. The resistance modulation activity was investigated using the anti-biofilm formation and efflux pump inhibition assays. Purification of the extract was carried out by chromatographic methods, and the isolated compounds were characterized based on nuclear magnetic resonance, Fourier transform infrared and mass spectrometry spectral data and comparison with published literature. The whole extract, methanol, ethyl acetate, and pet-ether fractions of L. africana all showed antibacterial activity against the test bacteria with MICs ranging from 62.5 to 500.0 µg/mL The whole extract demonstrated resistance modulation effect through strong biofilm inhibition and efflux pump inhibition activities against S. aureus ATCC 25923, E. coli ATCC 25922 and P. aeruginosa ATCC 27853. Chromatographic fractionation of the ethyl acetate fraction resulted in the isolation of a triterpenoid (4S,4αS,6αR,6βS,8αS,12αS,12βR,14αS,14βR)-4,4α,6β,8α,11,11,12β,14α-Octamethyloctadecahydropicene-1,3(2H,4H)-dione) and a phytosterol (β-sitosterol). These compounds showed antibacterial activity against susceptible bacteria at a MIC range of 31-125 µg/mL and potentiated the antibacterial activity of amoxicillin (at ¼ MIC of compounds) against E. coli and P. aeruginosa with modulation factors of 32 and 10, respectively. These compounds also demonstrated good anti-biofilm formation effect at a concentration range of 3-100 µg/mL, and bacterial efflux pump inhibition activity at ½ MIC and ¼ MIC against E. coli and P. aeruginosa. Loeseneriella africana stem bark extracts and constituents elicit considerable antibacterial, resistance modulation, and biofilm and efflux pump inhibition activities. The results justify the indigenous uses of L. africana for managing microbial infections.}, } @article {pmid38272420, year = {2024}, author = {Xiong, C and Xiong, C and Lu, J and Long, R and Jiao, H and Li, Y and Wang, B and Lin, Y and Ye, H and Lin, L and Wu, R}, title = {flgL mutation reduces pathogenicity of Aeromonas hydrophila by negatively regulating swimming ability, biofilm forming ability, adherence and virulence gene expression.}, journal = {International journal of biological macromolecules}, volume = {261}, number = {Pt 1}, pages = {129676}, doi = {10.1016/j.ijbiomac.2024.129676}, pmid = {38272420}, issn = {1879-0003}, abstract = {Aeromonas hydrophila is a serious human and animal co-pathogenic bacterium. Flagellum, a key virulence factor, is vital for bacterium tissue colonization and invasion. flgL is a crucial gene involved in the composition of flagellum. However, the impact of flgL on virulence is not yet clear. In this study, we constructed a stable mutant strain (△flgL-AH) using homologous recombination. The results of the attack experiments indicated a significant decrease in the virulence of △flgL-AH. The biological properties analysis revealed a significant decline in swimming ability and biofilm formation capacity in △flgL-AH and the transmission electron microscope results showed that the ∆flgL-AH strain did not have a flagellar structure. Moreover, a significant decrease in the adhesion capacity of ∆flgL-AH was found using absolute fluorescence quantitative polymerase chain reaction (PCR). The quantitative real-time PCR results showed that the expression of omp and the eight flagellum-related genes were down-regulated. In summary, flgL mutation leads to a reduction in pathogenicity possibly via decreasing the swimming ability, biofilm formation capacity and adhesion capacity, these changes might result from the down expression of omp and flagellar-related genes.}, } @article {pmid38270381, year = {2024}, author = {Fung, BL and Esin, JJ and Visick, KL}, title = {Vibrio fischeri: a model for host-associated biofilm formation.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0037023}, doi = {10.1128/jb.00370-23}, pmid = {38270381}, issn = {1098-5530}, abstract = {Multicellular communities of adherent bacteria known as biofilms are often detrimental in the context of a human host, making it important to study their formation and dispersal, especially in animal models. One such model is the symbiosis between the squid Euprymna scolopes and the bacterium Vibrio fischeri. Juvenile squid hatch aposymbiotically and selectively acquire their symbiont from natural seawater containing diverse environmental microbes. Successful pairing is facilitated by ciliary movements that direct bacteria to quiet zones on the surface of the squid's symbiotic light organ where V. fischeri forms a small aggregate or biofilm. Subsequently, the bacteria disperse from that aggregate to enter the organ, ultimately reaching and colonizing deep crypt spaces. Although transient, aggregate formation is critical for optimal colonization and is tightly controlled. In vitro studies have identified a variety of polysaccharides and proteins that comprise the extracellular matrix. Some of the most well-characterized matrix factors include the symbiosis polysaccharide (SYP), cellulose polysaccharide, and LapV adhesin. In this review, we discuss these components, their regulation, and other less understood V. fischeri biofilm contributors. We also highlight what is currently known about dispersal from these aggregates and host cues that may promote it. Finally, we briefly describe discoveries gleaned from the study of other V. fischeri isolates. By unraveling the complexities involved in V. fischeri's control over matrix components, we may begin to understand how the host environment triggers transient biofilm formation and dispersal to promote this unique symbiotic relationship.}, } @article {pmid38270107, year = {2024}, author = {Wang, W and Xu, W and Zhang, J and Xu, Y and Shen, J and Zhou, N and Li, Y and Zhang, M and Tang, BZ}, title = {One-Stop Integrated Nanoagent for Bacterial Biofilm Eradication and Wound Disinfection.}, journal = {ACS nano}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsnano.3c08054}, pmid = {38270107}, issn = {1936-086X}, abstract = {To meet the requirements of biomedical applications in the antibacterial realm, it is of great importance to explore nano-antibiotics for wound disinfection that can prevent the development of drug resistance and possess outstanding biocompatibility. Therefore, we attempted to synthesize an atomically dispersed ion (Fe) on phenolic carbon quantum dots (CQDs) combined with an organic photothermal agent (PTA) (Fe@SAC CQDs/PTA) via a hydrothermal/ultrasound method. Fe@SAC CQDs adequately exerted peroxidase-like activity while the PTA presented excellent photothermal conversion capability, which provided enormous potential in antibacterial applications. Based on our work, Fe@SAC CQDs/PTA exhibited excellent eradication of Escherichia coli (>99% inactivation efficiency) and Staphylococcus aureus (>99% inactivation efficiency) based on synergistic chemodynamic therapy (CDT) and photothermal therapy (PTT). Moreover, in vitro experiments demonstrated that Fe@SAC CQDs/PTA could inhibit microbial growth and promote bacterial biofilm destruction. In vivo experiments suggested that Fe@SAC CQDs/PTA-mediated synergistic CDT and PTT exhibited great promotion to wound disinfection and recovery effects. This work indicated that Fe@SAC CQDs/PTA could serve as a broad-spectrum antimicrobial nano-antibiotic, which was simultaneously beneficial for bacterial biofilm eradication, wound disinfection, and wound healing.}, } @article {pmid38269015, year = {2023}, author = {Ahmed, A and Ijaz, M and Khan, JA and Anjum, AA}, title = {Biofilm forming multidrug resistant Staphylococcus aureus of dairy origin: molecular and evolutionary perspectives.}, journal = {Iranian journal of veterinary research}, volume = {24}, number = {3}, pages = {193-204}, pmid = {38269015}, issn = {1728-1997}, abstract = {BACKGROUND: Biofilm production by Staphylococcus aureus is a prevailing cause of multidrug resistance. The evolutionary mechanisms of adaption with host and pathogenicity are poorly understood.

AIMS: The present study aimed to investigate the biofilm-forming potential, associated multidrug resistance, and the evolutionary analysis of S. aureus isolated from bovine subclinical mastitis.

METHODS: 122 S. aureus isolates were subjected to Congo red agar method (CRA), microtitre plate method (MTP), and PCR to check the biofilm-forming potential. The Kirby-Bauer disk diffusion method was used to evaluate the antibiotic resistance pattern. The icaA gene of isolates was subjected to molecular and evolutionary analysis using different bioinformatics tools.

RESULTS: The results showed that 63.93% of S. aureus isolates carried the icaA gene and the detection rate of CRA was higher (36.07%) compared to the MTP test (24.59%). A total of 78.21% and 56.41% of biofilm-positive isolates were methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA), respectively. All S. aureus isolates (100%) showed multidrug resistance. The molecular analysis showed an evolutionary link between isolates and revealed a strong codon bias, three different recombination events, and positive selection in some residues of the semi-conserved segments of the icaA gene.

CONCLUSION: The study concluded that biofilm-positive isolates have a high tendency to exhibit methicillin, vancomycin, and multidrug resistance. The findings suggest that mutation and selection are the most likely causes of codon bias in the icaA gene sequences. The variations led by recombination events and positive selection are suggestive of bacterial strategy to combat antimicrobial effects and to escape the host's immune surveillance.}, } @article {pmid38268790, year = {2023}, author = {Dai, J and Luo, W and Hu, F and Li, S}, title = {In vitro inhibition of Pseudomonas aeruginosa PAO1 biofilm formation by DZ2002 through regulation of extracellular DNA and alginate production.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1333773}, pmid = {38268790}, issn = {2235-2988}, abstract = {INTRODUCTION: Pseudomonas aeruginosa (P. aeruginosa) is a common pathogen associated with biofilm infections, which can lead to persistent infections. Therefore, there is an urgent need to develop new anti-biofilm drugs. DZ2002 is a reversible inhibitor that targets S-adenosylhomocysteine hydrolase and possesses anti-inflammatory and immune-regulatory activities. However, its anti-biofilm activity has not been reported yet.

METHODS AND RESULTS: Therefore, we investigated the effect of DZ2002 on P. aeruginosa PAO1 biofilm formation by crystal violet staining (CV), real-time quantitative polymerase chain reaction (RT-qPCR) and confocal laser scanning microscopy (CLSM). The results indicated that although DZ2002 didn't affect the growth of planktonic PAO1, it could significantly inhibit the formation of mature biofilms. During the inhibition of biofilm formation by DZ2002, there was a parallel decrease in the synthesis of alginate and the expression level of alginate genes, along with a weakening of swarming motility. However, these results were unrelated to the expression of lasI, lasR, rhII, rhIR. Additionally, we also found that after treatment with DZ2002, the biofilms and extracellular DNA content of PAO1 were significantly reduced. Molecular docking results further confirmed that DZ2002 had a strong binding affinity with the active site of S-adenosylhomocysteine hydrolase (SahH) of PAO1.

DISCUSSION: In summary, our results indicated that DZ2002 may interact with SahH in PAO1, inhibiting the formation of mature biofilms by downregulating alginate synthesis, extracellular DNA production and swarming motility. These findings demonstrate the potential value of DZ2002 in treating biofilm infections associated with P. aeruginosa.}, } @article {pmid38267428, year = {2024}, author = {Ling, X and Liu, X and Wang, K and Guo, M and Ou, Y and Li, D and Xiang, Y and Zheng, J and Hu, L and Zhang, H and Li, W}, title = {Lsr2 acts as a cyclic di-GMP receptor that promotes keto-mycolic acid synthesis and biofilm formation in mycobacteria.}, journal = {Nature communications}, volume = {15}, number = {1}, pages = {695}, pmid = {38267428}, issn = {2041-1723}, abstract = {Cyclic di-GMP (c-di-GMP) is a second messenger that promotes biofilm formation in several bacterial species, but the mechanisms are often unclear. Here, we report that c-di-GMP promotes biofilm formation in mycobacteria in a manner dependent on the nucleoid-associated protein Lsr2. We show that c-di-GMP specifically binds to Lsr2 at a ratio of 1:1. Lsr2 upregulates the expression of HadD, a (3R)-hydroxyacyl-ACP dehydratase, thus promoting the synthesis of keto-mycolic acid and biofilm formation. Thus, Lsr2 acts as a c-di-GMP receptor that links the second messenger's function to lipid synthesis and biofilm formation in mycobacteria.}, } @article {pmid38266912, year = {2024}, author = {Pourhajibagher, M and Ghafari, HA and Bahrami, R and Bahador, A}, title = {Photoinactivation of Enterococcus faecalis biofilm: In vitro antimicrobial effect of photoexcited Rutin-Gallium(III) complex via visible blue light.}, journal = {Journal of endodontics}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.joen.2024.01.007}, pmid = {38266912}, issn = {1878-3554}, abstract = {INTRODUCTION: Endodontic infection is a common problem that can result in tooth loss if not effectively treated. This study focused on investigating the use of a Rutin-Gallium(III) (Rutin-Ga(III)) complex-mediated antimicrobial photodynamic therapy (aPDT) for the photoinactivation of E. faecalis biofilm.

METHODS: The minimum biofilm eradication concentration (MBEC) of Rutin-Ga(III) complex and minimum biofilm eradication dose (MBED) of light-emitting diode (LED) against E. faecalis were evaluated. The antimicrobial effect of Rutin-Ga(III) complex-mediated aPDT against E. faecalis was assessed. Additionally, the expression of genes associated with E. faecalis virulence, such as ace, gelE, and esp as well as the production of reactive oxygen species (ROS) within the cells were evaluated.

RESULTS: The MBEC of the Rutin-Ga(III) complex was determined to be 25 μM, while the MBED of LED irradiation was defined as 5 min with an energy density of 300-420 J/cm[2]. The Rutin-Ga(III) complex-mediated aPDT demonstrated a significant dose-dependent reduction in the growth of E. faecalis biofilms. Moreover, aPDT led to increased intracellular ROS generation in treated E. faecalis cells. Furthermore, the mRNA levels of ace, gelE, and esp genes were significantly downregulated in E. faecalis treated with Rutin-Ga(III) complex-mediated aPDT (P<0.05).

CONCLUSION: Rutin-Ga(III) complex-mediated aPDT effectively reduces E. faecalis biofilm growth by disrupting biofilm structure and downregulating virulence genes. These findings highlight the potential of aPDT with Rutin-Ga(III) complex as an adjuvant therapeutic approach against E. faecalis biofilms.}, } @article {pmid38265501, year = {2024}, author = {Guliy, OI and Evstigneeva, SS and Shirokov, AA and Bunin, VD}, title = {Sensor system for analysis of biofilm sensitivity to ampicillin.}, journal = {Applied microbiology and biotechnology}, volume = {108}, number = {1}, pages = {172}, pmid = {38265501}, issn = {1432-0614}, mesh = {*Ampicillin ; Anti-Bacterial Agents ; Biofilms ; Electricity ; *Pseudomonas putida ; }, abstract = {The resistance of biofilms to antibiotics is a key factor that makes bacterial infections unsusceptible to antimicrobial therapy. The results of classical tests of cell sensitivity to antibiotics cannot be used to predict therapeutic success in infections associated with biofilm formation. We describe a simple and rapid method for the real-time evaluation of bacterial biofilm sensitivity to antibiotics, with Pseudomonas putida and ampicillin as examples. The method uses an electric biosensor to detect the difference between changes in the biofilm electric polarizability, thereby evaluating antibiotic sensitivity. The electric signals showed that P. putida biofilms were susceptible to ampicillin and that at high antibiotic concentrations, the biofilms differed markedly in their susceptibility (dose-dependent effect). The sensor also detected differences between biofilms before and after ampicillin treatment. The electric-signal changes enabled us to describe the physical picture of the processes occurring in bacterial biofilms in the presence of ampicillin. The approach used in this study is promising for evaluating the activity of various compounds against biofilms, because it permits a conclusion about the antibiotic sensitivity of biofilm bacteria to be made in real time and in a short period (analysis time, not longer than 20 min). An added strong point is that analysis can be done directly in liquid, without preliminary sample preparation. KEY POINTS: • Sensor system to analyze biofilm antimicrobial susceptibility is described. • The signal change depended on the ampicillin concentration (dose-dependent effect). • The sensor allows real-time determination of the antibiofilm effect of ampicillin.}, } @article {pmid38265243, year = {2024}, author = {Narciso, DAC and Pereira, A and Dias, NO and Monteiro, M and Melo, LF and Martins, FG}, title = {3D optical coherence tomography image processing in BISCAP: characterization of biofilm structure and properties.}, journal = {Bioinformatics (Oxford, England)}, volume = {}, number = {}, pages = {}, doi = {10.1093/bioinformatics/btae041}, pmid = {38265243}, issn = {1367-4811}, abstract = {MOTIVATION: BISCAP is a state-of-the-art tool for automatically characterizing biofilm images obtained from Optical Coherence Tomography (OCT). Limited availability of other software tools is reported in the field. BISCAP's first version processes 2D images only. Processing 3D images is a problem of greater scientific relevance since it deals with the entire structure of biofilms instead of their 2D slices.

RESULTS: Building on the image processing principles and algorithms proposed earlier for 2D images, these were adapted to the 3D case, and a more general implementation of BISCAP was developed. The primary goal concerns the extension of the initial methodology to incorporate the depth axis in 3D images; multiple improvements were also made to boost computational performance. The calculation of structural properties and visual outputs was extended to offer new insights into the 3D structure of biofilms. BISCAP was tested using 3D images of biofilms with different morphologies, consistently delivering accurate characterizations of 3D structures in a few minutes using standard laptop machines. Low user dependency is required for image analysis.

AVAILABILITY: BISCAP is available from https://github.com/diogonarciso/BISCAP. All images used in the tutorials and the validation examples are available from https://web.fe.up.pt/∼fgm/biscap3d.

SUPPLEMENTARY INFORMATION: User Manual and Appendix 1.}, } @article {pmid38265239, year = {2024}, author = {Maroc, L and Shaker, H and Shapiro, RS}, title = {Functional genetic characterization of stress tolerance and biofilm formation in Nakaseomyces (Candida) glabrata via a novel CRISPR activation system.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0076123}, doi = {10.1128/msphere.00761-23}, pmid = {38265239}, issn = {2379-5042}, abstract = {The overexpression of genes frequently arises in Nakaseomyces (formerly Candida) glabrata via gain-of-function mutations, gene duplication, or aneuploidies, with important consequences on pathogenesis traits and antifungal drug resistance. This highlights the need to develop specific genetic tools to mimic and study genetic amplification in this important fungal pathogen. Here, we report the development, validation, and applications of the first clustered regularly interspaced short palindromic repeats (CRISPR) activation (CRISPRa) system in N. glabrata for targeted genetic overexpression. Using this system, we demonstrate the ability of CRISPRa to drive high levels of gene expression in N. glabrata, and further assess optimal guide RNA targeting for robust overexpression. We demonstrate the applications of CRISPRa to overexpress genes involved in fungal pathogenesis and drug resistance and detect corresponding phenotypic alterations in these key traits, including the characterization of novel phenotypes. Finally, we capture strain variation using our CRISPRa system in two commonly used N. glabrata genetic backgrounds. Together, this tool will expand our capacity for functional genetic overexpression in this pathogen, with numerous possibilities for future applications.IMPORTANCENakaseomyces (formerly Candida) glabrata is an important fungal pathogen that is now the second leading cause of candidiasis infections. A common strategy that this pathogen employs to resist antifungal treatment is through the upregulation of gene expression, but we have limited tools available to study this phenomenon. Here, we develop, optimize, and apply the use of CRISPRa as a means to overexpress genes in N. glabrata. We demonstrate the utility of this system to overexpress key genes involved in antifungal susceptibility, stress tolerance, and biofilm growth. This tool will be an important contribution to our ability to study the biology of this important fungal pathogen.}, } @article {pmid38265212, year = {2024}, author = {Del Rey, YC and Schramm, A and L Meyer, R and Lund, MB and Schlafer, S}, title = {Combined pH ratiometry and fluorescence lectin-binding analysis (pH-FLBA) for microscopy-based analyses of biofilm pH and matrix carbohydrates.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0200723}, doi = {10.1128/aem.02007-23}, pmid = {38265212}, issn = {1098-5336}, abstract = {Bacterial biofilms have a complex and heterogeneous three-dimensional architecture that is characterized by chemically and structurally distinct microenvironments. Confocal microscopy-based pH ratiometry and fluorescence lectin-binding analysis (FLBA) are well-established methods to characterize pH developments and the carbohydrate matrix architecture of biofilms at the microscale. Here, we developed a combined analysis, pH-FLBA, to concomitantly map biofilm pH and the distribution of matrix carbohydrates in bacterial biofilms while preserving the biofilm microarchitecture. As a proof of principle, the relationship between pH and the presence of galactose- and fucose-containing matrix components was investigated in dental biofilms grown with and without sucrose. The pH response to a sucrose challenge was monitored in different areas at the biofilm base using the ratiometric pH-sensitive dye C-SNARF-4. Thereafter, the fucose- and galactose-specific fluorescently labeled lectins Aleuria aurantia lectin (AAL) and Morus nigra agglutinin G (MNA-G) were used to visualize carbohydrate matrix components in the same biofilm areas and their immediate surroundings. Sucrose during growth significantly decreased biofilm pH (P < 0.05) and increased the amounts of both MNA-G- and AAL-targeted matrix carbohydrates (P < 0.05). Moreover, it modulated the biofilm composition towards a less diverse community dominated by streptococci, as determined by 16S rRNA gene sequencing. Altogether, these results suggest that the production of galactose- and fucose-containing matrix carbohydrates is related to streptococcal metabolism and, thereby, pH profiles in dental biofilms. In conclusion, pH-FLBA using lectins with different carbohydrate specificities is a useful method to investigate the association between biofilm pH and the complex carbohydrate architecture of bacterial biofilms.IMPORTANCEBiofilm pH is a key regulating factor in several biological and biochemical processes in environmental, industrial, and medical biofilms. At the microscale, microbial biofilms are characterized by steep pH gradients and an extracellular matrix rich in carbohydrate components with diffusion-modifying properties that contribute to bacterial acid-base metabolism. Here, we propose a combined analysis of pH ratiometry and fluorescence lectin-binding analysis, pH-FLBA, to concomitantly investigate the matrix architecture and pH developments in microbial biofilms, using complex saliva-derived biofilms as an example. Spatiotemporal changes in biofilm pH are monitored non-invasively over time by pH ratiometry, while FLBA with lectins of different carbohydrate specificities allows mapping the distribution of multiple relevant matrix components in the same biofilm areas. As the biofilm structure is preserved, pH-FLBA can be used to investigate the in situ relationship between the biofilm matrix architecture and biofilm pH in complex multispecies biofilms.}, } @article {pmid38263940, year = {2024}, author = {Erdal, B and Baylan, B and Batar, B and Öztürk, A and Topçu, B}, title = {[Investigation of the Effect of Farnesol on Biofilm Formation by Candida albicans and Candida parapsilosis Complex Isolates].}, journal = {Mikrobiyoloji bulteni}, volume = {58}, number = {1}, pages = {49-62}, doi = {10.5578/mb.20249905r}, pmid = {38263940}, issn = {0374-9096}, abstract = {The incidence of infections caused by Candida species has significantly increased over the past three decades. Candida albicans is commonly recognized as the primary causative agent in cases of candidiasis; however, non-albicans Candida species, including Candida parapsilosis, are also frequently defined as pathogens. Treatment-resistant infections arise as a result of biofilm formation, which is one of the effective mechanisms in the pathogenesis of Candida infections. However, the mechanisms of action of farnesol, a quorum sensing (QS) system molecule, on biofilm formation by Candida species remain unclear. This study aimed to demonstrate the changes in the biofilm biomass of C.albicans and C.parapsilosis complex isolates in the presence of farnesol and reveal the expression of the EFG1 and BCR1 genes, which are believed to play a role in the production of QS molecules, using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis. C.albicans (n= 91) and C.parapsilosis complex (n= 29) isolates obtained from different clinical samples were included in the study. The minimum inhibitory concentration (MIC) values of farnesol were determined using the broth microdilution method according to the M27-A3 protocol of the Clinical and Laboratory Standards Institute (CLSI). The biofilm biomass of the isolates was examined without farnesol and at the MIC-0 and MIC-2 concentrations of farnesol. Changes in the expression of the biofilm-associated EFG1 and BCR1 genes were investigated using qRT-PCR. According to the results of the study, the MIC values of farnesol were detected in the range of 1-2 mM in 82.4% (n= 75) of the C.albicans isolates and in the range of 0.5-1 mM in 72.4% (n= 21) of the C.parapsilosis complex isolates. Of the C.albicans isolates, 27 (29.7%) exhibited a strong biofilm formation and 58 (63.7%) demonstrated a weaker biofilm formation, while these rates were 34.4% (n= 10) and 62.1% (n= 18), respectively, for the C.parapsilosis complex isolates. At the MIC-0 and MIC-2 concentrations, farnesol was observed to reduce biofilm biomass among C.albicans (n= 24, 88.9%) and C.parapsilosis complex (n= 8, 80.0%) isolates that formed strong biofilms and observed to increase biofilm biomass among those that formed weak biofilms [60.3% (n= 35) and 55.6% (n= 10), respectively]. On completion of the qRT-PCR analysis supporting the results of the biofilm experiment, it was determined that the expressions of the EFG1 and BCR1 genes decreased at the MIC-0 and MIC-2 concentrations of farnesol among the strong biofilm-forming C.albicans and C.parapsilosis complex isolates, but there was an increase in gene expressions among the weak biofilm-forming isolates. In addition to the antifungal effect of farnesol on Candida species, this study provided data on the efficacy of the MIC-0 and MIC-2 concentrations of farnesol against Candida biofilm biomass. Although our results suggest that farnesol can be used as an alternative agent to reduce biofilm formation in Candida infections, they need to be supported by further studies. Moreover, this research has significance as it represents the first study to determine the EFG1 and BCR1 gene expressions among C.parapsilosis complex isolates in the presence of farnesol.}, } @article {pmid38263503, year = {2024}, author = {Vélez, MV and Colello, R and Nieto, MV and Paz, LE and Etcheverría, AI and Vidal, R and Padola, NL}, title = {Transcription levels of hes and their involvement in the biofilm formation of Shiga toxin-producing Escherichia coli O91.}, journal = {Veterinary research communications}, volume = {}, number = {}, pages = {}, pmid = {38263503}, issn = {1573-7446}, abstract = {Shiga toxin-producing Escherichia coli (STEC) are recognized as being responsible for many cases of foodborne diseases worldwide. Cattle are the main reservoir of STEC, shedding the microorganisms in their feces. The serogroup STEC O91 has been associated with hemorrhagic colitis and hemolytic uremic syndrome. Locus of Adhesion and Autoaggregation (LAA) and its hes gene are related to the pathogenicity of STEC and the ability to form biofilms. Considering the frequent isolation of STEC O91, the biofilm-forming ability, and the possible role of hes in the pathogenicity of STEC, we propose to evaluate the ability of STEC to form biofilms and to evaluate the expression of hes before and after of biofilm formation. All strains were classified as strong biofilm-forming. The hes expression showed variability between strains before and after biofilm formation, and this may be due to other genes carried by each strain. This study is the first to report the relationship between biofilm formation, and hes expression and proposes that the analysis and diagnosis of LAA, especially hes as STEC O91 virulence factors, could elucidate these unknown mechanisms. Considering that there is no specific treatment for HUS, only supportive care, it is necessary to know the survival and virulence mechanisms of STEC O91.}, } @article {pmid38262493, year = {2024}, author = {Barua, M and Bandyopadhyay, S and Wasai, A and Ghosh, M and Roy, I and Ghosh, P and Koner, S and Rizzoli, C and Roy, A and Saha, S and Mandal, S}, title = {A trinuclear Zn (II) schiff base dicyanamide complex attenuates bacterial biofilm formation by ROS generation and membrane damage and exhibits anticancer activity.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106548}, doi = {10.1016/j.micpath.2024.106548}, pmid = {38262493}, issn = {1096-1208}, abstract = {A trinuclear Zn (II) complex, [(ZnL{N(CN)2} )2Zn], termed complex 1 has been synthesized by the reaction of an aqueous solution of sodium dicyanamide to the methanolic solution of Zn (CH3COO)2, 2H2O and corresponding Schiff base (H2L) which is derived from 1:2 condensation of 1, 4 butane diamine with 3-ethoxy salicylaldehyde. Complex 1 is characterized by elemental analysis, IR, UV and Single X-ray diffraction study. Drug resistance is a growing global public health concern that has prompted researchers to look into advanced alternative treatment modalities. In this context, complex 1 has shown promising antibacterial and Antibiofilm efficacy against gram-positive Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus strains. Complex 1 attenuated Staphylococcal biofilm formation by reducing several virulence factors including the formation of extracellular polysaccharide matrix, slime, haemolysin, staphyloxanthin, auto-aggregation, cell surface hydrophobicity, and motility. Notably, complex 1 mechanistically potentiated Reactive Oxygen Species (ROS) generation within the bacterial cells, leading to the damage of bacterial cell membrane followed by DNA leakage and thereby impeding the growth of Staphylococcus aureus. Furthermore, complex 1 significantly exhibited anticancer activity by reducing the growth of prostate adenocarcinoma cells. It obstructed the migration of cancer cells by potentiating apoptosis and arresting the cell cycle at the G2/M phase. In summary, complex 1 could act as a potent candidate for the generation of novel antibacterial, Antibiofilm as well as anticancer treatment regimens for the management of drug-resistant biofilm-mediated Staphylococcus aureus infection and lethal prostate malignancy.}, } @article {pmid38262082, year = {2024}, author = {Kadaikunnan, S and Vijayaragavan, P and Rathi, MA and Balamuralikrishnan, B and Alharbi, NS and Gopalakrishnan, VK and Purushothaman, S and Sivanesan, R}, title = {Antibacterial and biofilm disruptive nonribosomal lipopeptides from Streptomyces parvulus against multidrug-resistant bacterial infections.}, journal = {Journal of infection and public health}, volume = {17}, number = {3}, pages = {450-456}, doi = {10.1016/j.jiph.2024.01.001}, pmid = {38262082}, issn = {1876-035X}, abstract = {BACKGROUND: In recent years, new drugs for the treatment of various diseases, thereby the emergence of antimicrobial resistance tremendously increased because of the increased consumption rate of various drugs. However, the irrational use of antibiotics increases the microbial resistance along with that the frequency of mortality associated with infections is higher. Broad-spectrum antibiotics were effectively against various bacteria and the unrestricted application of antibiotics lead to the emergence of drug resistance. The present study was aimed to detect the antibacterial properties of lipopeptide novel drug producing Streptomyces parvulus.

METHODS: A lipopeptide-producing S. parvulus was isolated from the soil sample. The inhibitory effect of lipopeptide was detected against Gram-positive and Gram-negative bacteria. Bactericidal activity and minimum inhibitory concentration (MIC) were assayed. The IC50 value was analysed against ovarian and human melanoma cell lines. The experimental mouse model was infected withKlebsiella pneumoniae and treated with lipopeptide and bactericidal activity was determined.

RESULTS: The results indicated that the antibacterial activity of lipopeptide ranges from 13 ± 1 mm to 32 ± 2 mm against Gram-positive and Gram-negative strains. The lowest MIC value was noted as 1.5 ± 0.1 µg/mL against K. pneumoniae and the highest against E. aerogenes (7.5 ± 0.2 µg/mL). The IC50 value was considerably high for the ovarian cell lines and human melanoma cell lines (426 µg/mL and 503 µg/mL). At 25 µg/mL concentration of lipopeptide, only 16.4% inhibition was observed in the ovarian cell line whereas 20.2% inhibition was achieved at this concentration in the human melanoma cell line. Lipopeptide inhibited bacterial growth and was completely inhibited at a concentration of 20 µg/mL. Lipopeptide reduced bacterial load in experimental mice compared to control (p < 0.05).

CONCLUSION: Lipopeptide activity and its non-toxic nature reveal that it may serve as a lead molecule in the development of a novel drug.}, } @article {pmid38261908, year = {2024}, author = {Riedel, A and Neukamm, MA and Klima, M and Henkel, K and Auwärter, V and Altenburger, MJ}, title = {Drugs in dental biofilm and enamel - A pilot study.}, journal = {Heliyon}, volume = {10}, number = {1}, pages = {e23177}, pmid = {38261908}, issn = {2405-8440}, abstract = {OBJECTIVE: Enamel and dental biofilm might serve as alternative matrices for determination of illicit and medical drugs. Thus, this study aims at evaluating possible correlations between detected drug concentrations in the matrices and simulated drug use in situ.

DESIGN: Eleven subjects wore intraoral splints with embedded demineralized bovine enamel samples. Drug use was simulated by mouth rinsing with a 1.0 μg/ml drug solution three times daily for 1 min (study A) or by incubation of the splints in a 10 μg/ml drug solution once a day for 30 min (study B). Amphetamines, opiates, cocaine and benzoylecgonine were used as drugs. After 11 days, biofilm and enamel samples of the intraoral splints were analyzed by liquid chromatography mass spectrometry after drying and extraction via ultrasonication with acetonitrile (biofilm) or methanol (enamel).

RESULTS: In study A, median and mean drug concentration ± standard deviation were 1.3 pg/mg and 6.4 ± 11 pg/mg in biofilm and 0.2 pg/mg and 0.5 ± 0.9 pg/mg in enamel. In study B, median and mean drug concentration ± standard deviation were 350 pg/mg and 1100 ± 1600 pg/mg in biofilm and 5.8 pg/mg and 9.9 ± 10 pg/mg in enamel.

CONCLUSIONS: Overall, there were considerable interindividual concentration differences. Correlations between concentrations in the two sample materials were shown. The results of this pilot study revealed a dependence of concentrations on intensity and duration of drug contact. Thus, important information on past drug use might be provided in forensic cases by analysis of dental biofilm and enamel.}, } @article {pmid38261537, year = {2024}, author = {Rayi, S and Cai, Y and Greenwich, JL and Fuqua, C and Gerdt, JP}, title = {Interbacterial Biofilm Competition through a Suite of Secreted Metabolites.}, journal = {ACS chemical biology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acschembio.3c00655}, pmid = {38261537}, issn = {1554-8937}, abstract = {Polymicrobial biofilms are ubiquitous, and the complex interspecies interactions within them are cryptic. We discovered the chemical foundation of antagonistic interactions in a model dual-species biofilm in which Pseudomonas aeruginosa inhibits the biofilm formation of Agrobacterium tumefaciens. Three known siderophores produced by P. aeruginosa (pyoverdine, pyochelin, and dihydroaeruginoic acid) were each capable of inhibiting biofilm formation. Surprisingly, a mutant that was incapable of producing these siderophores still secreted an antibiofilm metabolite. We discovered that this inhibitor was N[5]-formyl-N[5]-hydroxy-l-ornithine (fOHOrn)─a precursor in pyoverdine biosynthesis. Unlike the siderophores, this inhibitor did not appear to function via extracellular metal sequestration. In addition to this discovery, the compensatory overproduction of a new biofilm inhibitor illustrates the risk of pleiotropy in genetic knockout experiments. In total, this work lends new insight into the chemical nature of dual-species biofilm regulation and reveals a new naturally produced inhibitor of A. tumefaciens biofilm formation.}, } @article {pmid38261525, year = {2024}, author = {Baxter, KJ and Sargison, FA and Fitzgerald, JR and McConnell, G and Hoskisson, PA}, title = {Time-lapse mesoscopy of Candida albicans and Staphylococcus aureus dual-species biofilms reveals a structural role for the hyphae of C. albicans in biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {170}, number = {1}, pages = {}, doi = {10.1099/mic.0.001426}, pmid = {38261525}, issn = {1465-2080}, abstract = {Polymicrobial infection with Candida albicans and Staphylococcus aureus may result in a concomitant increase in virulence and resistance to antimicrobial drugs. This enhanced pathogenicity phenotype is mediated by numerous factors, including metabolic processes and direct interaction of S. aureus with C. albicans hyphae. The overall structure of biofilms is known to contribute to their recalcitrance to treatment, although the dynamics of direct interaction between species and how it contributes to pathogenicity is poorly understood. To address this, a novel time-lapse mesoscopic optical imaging method was developed to enable the formation of C. albicans/S. aureus whole dual-species biofilms to be followed. It was found that yeast-form or hyphal-form C. albicans in the biofilm founder population profoundly affects the structure of the biofilm as it matures. Different sub-populations of C. albicans and S. aureus arise within each biofilm as a result of the different C. albicans morphotypes, resulting in distinct sub-regions. These data reveal that C. albicans cell morphology is pivotal in the development of global biofilm architecture and the emergence of colony macrostructures and may temporally influence synergy in infection.}, } @article {pmid38260905, year = {2023}, author = {Le, TN and Tran, NTH and Pham, VNT and Van-Thi, ND and Tran, HTM}, title = {Anti-ultraviolet, antibacterial, and biofilm eradication activities against Cutibacterium acnes of melanins and melanin derivatives from Daedaleopsis tricolor and Fomes fomentarius.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1305778}, pmid = {38260905}, issn = {1664-302X}, abstract = {Fomes fomentarius and Daedaleopsis tricolor produced significant amounts of water-insoluble melanins, and our previous study successfully enhanced their water solubility by arginine modification. This research aimed to investigate the anti-ultraviolet, antibacterial, and biofilm eradication activities of both the melanins and arginine-modified melanin (melanin derivatives) from these two fungi against an acne-causing bacterium (Cutibacterium acnes). Apart from these, the cytotoxicity of the melanins and melanin derivatives on human skin cells was also evaluated. Melanin derivatives of both two fungi showed significantly higher antibacterial and biofilm eradication activities compared with their original forms. Specifically, the MIC50 values of the melanin derivatives (1,000 μg/mL) are the same as those of erythromycin. Regarding biofilm eradication capacity, the MBEC50 value of D. tricolor melanin derivative (250 μg/mL) was just half of both erythromycin and F. fomentarius melanin derivative. However, it required a 2-fold higher concentration of melanin derivatives than erythromycin to inhibit 90% of the bacterial population and eradicate 90% of their biofilm. Regarding anti-ultraviolet activity, blending melanins or melanin derivatives with a moisturizer/sunscreen enhanced their UV light absorption and the sun protection factor (SPF) values. In addition, melanins showed better effects than their derivatives, and those of D. tricolor were better than F. fomentarius. Remarkably, adding D. tricolor melanin (10%) to a Nivea pure cream could turn this cream into a broad-spectrum sunscreen, with its SPF value and critical wavelength increasing from 7.74 and 338.67 to 14.02 and 377.0, respectively. In addition, adding melanin or a melanin derivative of D. tricolor to an Olay sunscreen enhanced the SPF and the critical wavelength of the sunscreen from 17.25 and 371.67 to 23.82 and 374 and 23.38 and 372, respectively. Notably, melanins and melanin derivatives showed no toxicity in human fibroblasts. The obtained data suggest that arginine modification significantly enhanced the antibacterial and biofilm eradication activities of melanins from D. tricolor and F. fomentarius. However, this is not the case when it comes to their anti-ultraviolet activities. In addition, melanin and melanin derivatives from D. tricolor are potential candidates for anti-acne sunscreen products and are worth further investigation.}, } @article {pmid38260874, year = {2023}, author = {Zhang, YL and Sun, ZS and Hong, WJ and Chen, Y and Zhou, YF and Luo, SK}, title = {Biofilm formation is a risk factor for late and delayed complications of filler injection.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1297948}, pmid = {38260874}, issn = {1664-302X}, abstract = {INTRODUCTION: Biofilm formation is a major cause of delayed-graft complications. Similarly to implants, dermal fillers carry the risk of biofilm formation, which can lead to the development of nodules, chronic inflammatory reactions, abscesses and other complications. In this study, we investigated the late or delayed complications associated with biofilm formation on dermal fillers.

METHODS: In this retrospective analysis, we analyzed all cases of complications caused by filler injections at a single center between January 2017 and December 2022, the majority of which comprised nodule formation and chronic persistent inflammatory reactions. The risk of biofilm formation with fillers was summarized and analyzed based on the results of bacterial culture and pathological examination.

RESULTS: Sixty-one patients were enrolled, including 42 cases of nodule formation, 15 of chronic inflammatory reactions, and 4 of active infection. Bacterial culture of the tissue samples obtained from seven patients after surgical treatment were positive, and comprised four cases of Staphylococcus aureus, one case of Staphylococcus epidermidis, one case of Staphylococcus saprophyticus and one case of Mycobacterium abscessus. The corresponding histopathological results indicated extensive mononuclear lymphocyte infiltration, with a giant cell reaction in the fibrous connective tissue.

CONCLUSION: The results of this study suggest that biofilm formation is a significant risk factor for late and delayed complications following filler injection, and is caused by the contamination of resident bacteria and recessive infection at the injection site.}, } @article {pmid38258011, year = {2024}, author = {Morot, A and Delavat, F and Bazire, A and Paillard, C and Dufour, A and Rodrigues, S}, title = {Genetic Insights into Biofilm Formation by a Pathogenic Strain of Vibrio harveyi.}, journal = {Microorganisms}, volume = {12}, number = {1}, pages = {}, doi = {10.3390/microorganisms12010186}, pmid = {38258011}, issn = {2076-2607}, support = {GIS Europole Mer 2009//Région Bretagne/ ; ANR-17-EURE-0015//ISblue project/ ; FEDER//LBCM/ ; }, abstract = {The Vibrio genus includes bacteria widely distributed in aquatic habitats and the infections caused by these bacteria can affect a wide range of hosts. They are able to adhere to numerous surfaces, which can result in biofilm formation that helps maintain them in the environment. The involvement of the biofilm lifestyle in the virulence of Vibrio pathogens of aquatic organisms remains to be investigated. Vibrio harveyi ORM4 is a pathogen responsible for an outbreak in European abalone Haliotis tuberculata populations. In the present study, we used a dynamic biofilm culture technique coupled with laser scanning microscopy to characterize the biofilm formed by V. harveyi ORM4. We furthermore used RNA-seq analysis to examine the global changes in gene expression in biofilm cells compared to planktonic bacteria, and to identify biofilm- and virulence-related genes showing altered expression. A total of 1565 genes were differentially expressed, including genes associated with motility, polysaccharide synthesis, and quorum sensing. The up-regulation of 18 genes associated with the synthesis of the type III secretion system suggests that this virulence factor is induced in V. harveyi ORM4 biofilms, providing indirect evidence of a relationship between biofilm and virulence.}, } @article {pmid38257980, year = {2024}, author = {Marzucco, A and Gatti, G and Montanari, MS and Fantini, M and Colosimo, C and Tamburini, MV and Arfilli, V and Morotti, M and Schiavone, P and Congestrì, F and Manera, M and Denicolò, A and Brandolini, M and Taddei, F and Grumiro, L and Zannoli, S and Dirani, G and De Pascali, AM and Sambri, V and Cricca, M}, title = {Evaluation of Biofilm Production and Antifungal Susceptibility to Fluconazole in Clinical Isolates of Candida spp. in Both Planktonic and Biofilm Form.}, journal = {Microorganisms}, volume = {12}, number = {1}, pages = {}, doi = {10.3390/microorganisms12010153}, pmid = {38257980}, issn = {2076-2607}, support = {Ricerca Fondamentale Orientata (RFO) 2021 and 2022//Monica Cricca/ ; 352/2021 - CUP J33C22001330009//the European Union-NextGenerationEU through the Italian Ministry of University and Research under PNRR-Mission 4 Component 2, Investment 3.3 "Partnerships extended to universities, re-search centres/ ; }, abstract = {Candida spp. are an important opportunistic pathogen that can represent a possible cause of severe infections, especially in immunocompromised individuals. The clinical impact of Candida spp. depends, in part, on the ability to form biofilms, communities of nestled cells into the extracellular matrix. In this study, we compared the biofilm formation ability of 83 strains of Candida spp. isolated from blood cultures and other materials, such as respiratory samples, urine, and exudate, and their sensitivity to fluconazole (FLZ). Strains were divided into tertiles to establish cut-offs to classify isolates as low, moderate, or high biofilm producers (<0.26, 0.266-0.839, >0.839) and biofilms with low, moderate, or high metabolic activity (<0.053, 0.053-0.183, >0.183). A non-linear relationship between biofilm production and metabolic activity was found in C. glabrata and C. tropicalis. In addition, the increase in minimum biofilm eradication concentrations (MBEC50) compared to the Minor Inhibitory Concentration (PMIC) of the planktonic form in Candida spp. confirms the role of biofilm in the induction of resistance to FLZ.}, } @article {pmid38257953, year = {2024}, author = {Grassia, G and Bagnarino, J and Siciliano, M and Barbarini, D and Corbella, M and Cambieri, P and Baldanti, F and Monzillo, V}, title = {Phenotypic and Genotypic Assays to Evaluate Coagulase-Negative Staphylococci Biofilm Production in Bloodstream Infections.}, journal = {Microorganisms}, volume = {12}, number = {1}, pages = {}, doi = {10.3390/microorganisms12010126}, pmid = {38257953}, issn = {2076-2607}, abstract = {Coagulase-negative staphylococci (CoNS) are commensal on human body surfaces and, for years, they were not considered a cause of bloodstream infection and were often regarded as contamination. However, the involvement of CoNS in nosocomial infection is increasingly being recognized. The insertion of cannulas and intravascular catheters represents the primary source of CoNS entry into the bloodstream, causing bacteremia and sepsis. They owe their pathogenic role to their ability to produce biofilms on surfaces, such as medical devices. In this study, we evaluate the adhesive capacity of CoNS isolated from blood cultures by comparing a spectrophotometric phenotypic assay with genotypic analysis based on the evidence of the ica operon. We retrospectively reviewed the database of CoNS isolated from blood cultures from January to December 2021 that were considered responsible for 361 bloodstream infections. Eighty-nine CoNS were selected among these. Our data show that Staphylococcus epidermidis was the predominant species isolated, expressing greater adhesive capacities, especially those with the complete operon. Knowledge of the adhesive capabilities of a microorganism responsible for sepsis can be useful in implementing appropriate corrective and preventive measures, since conventional antibiotic therapy cannot effectively eradicate biofilms.}, } @article {pmid38257873, year = {2023}, author = {Huq, M and Wahid, SUH and Istivan, T}, title = {Biofilm Formation in Campylobacter concisus: The Role of the luxS Gene.}, journal = {Microorganisms}, volume = {12}, number = {1}, pages = {}, doi = {10.3390/microorganisms12010046}, pmid = {38257873}, issn = {2076-2607}, abstract = {Campylobacter concisus is a bacterium that inhabits human oral cavities and is an emerging intestinal tract pathogen known to be a biofilm producer and one of the bacterial species found in dental plaque. In this study, biofilms of oral and intestinal C. concisus isolates were phenotypically characterized. The role of the luxS gene, which is linked to the regulation of biofilm formation in other pathogens, was assessed in relation to the pathogenic potential of this bacterium. Biofilm formation capacity was assessed using phenotypic assays. Oral strains were shown to be the highest producers. A luxS mutant was created by inserting a kanamycin cassette within the luxS gene of the highest biofilm-forming isolate. The loss of the polar flagellum was observed with scanning and transmission electron microscopy (SEM and TEM). Furthermore, the luxS mutant exhibited a significant reduction (p < 0.05) in biofilm formation, motility, and its expression of flaB, in addition to the capability to invade intestinal epithelial cells, compared to the parental strain. The study concluded that C. concisus oral isolates are significantly higher biofilm producers than the intestinal isolates and that LuxS plays a role in biofilm formation, invasion, and motility in this bacterium.}, } @article {pmid38257793, year = {2024}, author = {Golosova, NN and Khlusevich, YA and Morozova, VV and Matveev, AL and Kozlova, YN and Tikunov, AY and Panina, EA and Tikunova, NV}, title = {Characterization of a Thermostable Endolysin of the Aeribacillus Phage AeriP45 as a Potential Staphylococcus Biofilm-Removing Agent.}, journal = {Viruses}, volume = {16}, number = {1}, pages = {}, doi = {10.3390/v16010093}, pmid = {38257793}, issn = {1999-4915}, support = {the project grant no. 075-15-2021-1085//Ministry of Science and Higher Education of Russian Federation/ ; }, abstract = {Multidrug-resistant Gram-positive bacteria, including bacteria from the genus Staphylococcus, are currently a challenge for medicine. Therefore, the development of new antimicrobials is required. Promising candidates for new antistaphylococcal drugs are phage endolysins, including endolysins from thermophilic phages against other Gram-positive bacteria. In this study, the recombinant endolysin LysAP45 from the thermophilic Aeribacillus phage AP45 was obtained and characterized. The recombinant endolysin LysAP45 was produced in Escherichia coli M15 cells. It was shown that LysAP45 is able to hydrolyze staphylococcal peptidoglycans from five species and eleven strains. Thermostability tests showed that LysAP45 retained its hydrolytic activity after incubation at 80 °C for at least 30 min. The enzymatically active domain of the recombinant endolysin LysAP45 completely disrupted biofilms formed by multidrug-resistant S. aureus, S. haemolyticus, and S. epidermidis. The results suggested that LysAP45 is a novel thermostable antimicrobial agent capable of destroying biofilms formed by various species of multidrug-resistant Staphylococcus. An unusual putative cell-binding domain was found at the C-terminus of LysAP45. No domains with similar sequences were found among the described endolysins.}, } @article {pmid38257587, year = {2024}, author = {Suriasni, PA and Faizal, F and Hermawan, W and Subhan, U and Panatarani, C and Joni, IM}, title = {IoT Water Quality Monitoring and Control System in Moving Bed Biofilm Reactor to Reduce Total Ammonia Nitrogen.}, journal = {Sensors (Basel, Switzerland)}, volume = {24}, number = {2}, pages = {}, doi = {10.3390/s24020494}, pmid = {38257587}, issn = {1424-8220}, support = {2203/UN6.3.1/PT.00/2022//Padjadjaran University/ ; 1959/UN6.3.1/PT.00/2023//Padjadjaran University/ ; }, abstract = {Traditional aquaculture systems appear challenged by the high levels of total ammoniacal nitrogen (TAN) produced, which can harm aquatic life. As demand for global fish production continues to increase, farmers should adopt recirculating aquaculture systems (RAS) equipped with biofilters to improve the water quality of the culture. The biofilter plays a crucial role in ammonia removal. Therefore, a biofilter such as a moving bed biofilm reactor (MBBR) biofilter is usually used in the RAS to reduce ammonia. However, the disadvantage of biofilter operation is that it requires an automatic system with a water quality monitoring and control system to ensure optimal performance. Therefore, this study focuses on developing an Internet of Things (IoT) system to monitor and control water quality to achieve optimal biofilm performance in laboratory-scale MBBR. From 35 days into the experiment, water quality was maintained by an aerator's on/off control to provide oxygen levels suitable for the aquatic environment while monitoring the pH, temperature, and total dissolved solids (TDS). When the amount of dissolved oxygen (DO) in the MBBR was optimal, the highest TAN removal efficiency was 50%, with the biofilm thickness reaching 119.88 μm. The forthcoming applications of the IoT water quality monitoring and control system in MBBR enable farmers to set up a system in RAS that can perform real-time measurements, alerts, and adjustments of critical water quality parameters such as TAN levels.}, } @article {pmid38257309, year = {2024}, author = {Ahmad, SS and Siddiqui, MF and Maqbool, F and Ullah, I and Adnan, F and Albutti, A and Alsowayeh, N and Rahman, Z}, title = {Combating Cariogenic Streptococcus mutans Biofilm Formation and Disruption with Coumaric Acid on Dentin Surface.}, journal = {Molecules (Basel, Switzerland)}, volume = {29}, number = {2}, pages = {}, doi = {10.3390/molecules29020397}, pmid = {38257309}, issn = {1420-3049}, support = {NA//Deanship of Scientific Research, Qassim University, Buraydah 51452, Saudi Arabia./ ; }, abstract = {Streptococcus mutans, the primary cause of dental caries, relies on its ability to create and sustain a biofilm (dental plaque) for survival and pathogenicity in the oral cavity. This study was focused on the antimicrobial biofilm formation control and biofilm dispersal potential of Coumaric acid (CA) against Streptococcus mutans on the dentin surface. The biofilm was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability assay, microtiter plate assay, production of extracellular polymeric substances (EPSs), florescence microscopy (surface coverage and biomass μm[2]) and three-dimensional (3D) surface plots. It was observed that CA at 0.01 mg/mL reduced bacterial growth by 5.51%, whereases at 1 mg/mL, a significant (p < 0.05) reduction (98.37%) was observed. However, at 1 mg/mL of CA, a 95.48% biofilm formation reduction was achieved, while a 73.45% biofilm dispersal (after 24 h. treatment) was achieved against the preformed biofilm. The MTT assay showed that at 1 mg/mL of CA, the viability of bacteria in the biofilm was markedly (p < 0.05) reduced to 73.44%. Moreover, polysaccharide (EPS) was reduced to 24.80 μg/mL and protein (EPS) to 41.47 μg/mL. ImageJ software (version 1.54 g) was used to process florescence images, and it was observed that the biofilm mass was reduced to 213 (μm[2]); the surface coverage was reduced to 0.079%. Furthermore, the 3D surface plots showed that the untreated biofilm was highly dense, with more fibril-like projections. Additionally, molecular docking predicted a possible interaction pattern of CA (ligand) with the receptor Competence Stimulating Peptide (UA159sp, PDB ID: 2I2J). Our findings suggest that CA has antibacterial and biofilm control efficacy against S. mutans associated with dental plaque under tested conditions.}, } @article {pmid38256922, year = {2024}, author = {Janeczko, M and Kochanowicz, E}, title = {Biochanin A Inhibits the Growth and Biofilm of Candida Species.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {17}, number = {1}, pages = {}, doi = {10.3390/ph17010089}, pmid = {38256922}, issn = {1424-8247}, abstract = {The aim of this study was to investigate the antifungal activity of biochanin A (BCA) against planktonic growth and biofilms of six Candida species, including C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, C. auris, and C. krusei. We applied various assays that determined (a) the antimicrobial effect on growth of Candida species, (b) the effect on formation of hyphae and biofilm, (c) the effect on the expression of genes related to hyphal growth and biofilm formation, (d) the influence on cell wall structure, and (e) the effect on cell membrane integrity and permeability. Moreover, disk diffusion tests were used to investigate the effect of a combination of BCA with fluconazole to assess their possible synergistic effect on drug-resistant C. albicans, C. glabrata, and C. auris. Our results showed that the BCA MIC50 values against Candida species ranged between 125 µg/mL and 500 µg/mL, and the MIC90 values were in a concentration range from 250 µg/mL to 1000 µg/mL. The treatment with BCA inhibited adhesion of cells, cell surface hydrophobicity (CSH), and biofilm formation and reduced hyphal growth in all the analyzed Candida species. Real-time qRT-PCR revealed that BCA down-regulated the expression of biofilm-specific genes in C. albicans. Furthermore, physical destruction of C. albicans cell membranes and cell walls as a result of the treatment with BCA was observed. The combination of BCA and fluconazole did not exert synergistic effects against fluconazole-resistant Candida.}, } @article {pmid38256125, year = {2024}, author = {Zhang, J and Liu, Y and Hu, J and Leng, G and Liu, X and Cui, Z and Wang, W and Ma, Y and Sha, S}, title = {Cellulase Promotes Mycobacterial Biofilm Dispersal in Response to a Decrease in the Bacterial Metabolite Gamma-Aminobutyric Acid.}, journal = {International journal of molecular sciences}, volume = {25}, number = {2}, pages = {}, doi = {10.3390/ijms25021051}, pmid = {38256125}, issn = {1422-0067}, support = {LJKZ0846//Educational Department of Liaoning Province/ ; }, abstract = {Biofilm dispersal contributes to bacterial spread and disease transmission. However, its exact mechanism, especially that in the pathogen Mycobacterium tuberculosis, is unclear. In this study, the cellulase activity of the M. tuberculosis Rv0062 protein was characterized, and its effect on mycobacterial biofilm dispersal was analyzed by observation of the structure and components of Rv0062-treated biofilm in vitro. Meanwhile, the metabolite factors that induced cellulase-related biofilm dispersal were also explored with metabolome analysis and further validations. The results showed that Rv0062 protein had a cellulase activity with a similar optimum pH (6.0) and lower optimum temperature (30 °C) compared to the cellulases from other bacteria. It promoted mycobacterial biofilm dispersal by hydrolyzing cellulose, the main component of extracellular polymeric substrates of mycobacterial biofilm. A metabolome analysis revealed that 107 metabolites were significantly altered at different stages of M. smegmatis biofilm development. Among them, a decrease in gamma-aminobutyric acid (GABA) promoted cellulase-related biofilm dispersal, and this effect was realized with the down-regulation of the bacterial signal molecule c-di-GMP. All these findings suggested that cellulase promotes mycobacterial biofilm dispersal and that this process is closely associated with biofilm metabolite alterations.}, } @article {pmid38254292, year = {2024}, author = {Carneiro, DG and Pereira Aguilar, A and Mantovani, HC and Mendes, TAO and Vanetti, MCD}, title = {The quorum sensing molecule C12-HSL promotes biofilm formation and increases adrA expression in Salmonella Enteritidis under anaerobic conditions.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2024.2305385}, pmid = {38254292}, issn = {1029-2454}, abstract = {Acyl-homoserine lactones (AHLs) are quorum-sensing signaling molecules in Gram-negative bacteria and positively regulate biofilm formation in Salmonella under specific conditions. In this study, biofilm formation in Salmonella enterica was evaluated at 28 and 37 °C, under aerobic and anaerobic conditions. Additionally, the influence of the N-dodecanoyl-DL-homoserine lactone (C12-HSL) on biofilm formation and the expression of genes related to the synthesis of structural components, regulation, and quorum sensing was assessed under anaerobiosis at 28 and 37 °C. Biofilm formation was found not to be influenced by the atmospheric conditions at 28 °C. However, it was reduced at 37 °C under anaerobiosis. C12-HSL enhanced biofilm formation at 37 °C under anaerobiosis and increased the expression of the adrA and luxS genes, suggesting an increase in c-di-GMP, a second messenger that controls essential physiological functions in bacteria. These results provide new insights into the regulation of biofilm formation in Salmonella under anaerobic conditions.}, } @article {pmid38253591, year = {2024}, author = {Healy, HG and Ehde, A and Bartholow, A and Kantor, RS and Nelson, KL}, title = {Responses of drinking water bulk and biofilm microbiota to elevated water age in bench-scale simulated distribution systems.}, journal = {NPJ biofilms and microbiomes}, volume = {10}, number = {1}, pages = {7}, pmid = {38253591}, issn = {2055-5008}, support = {CBET-1804118//National Science Foundation (NSF)/ ; EEC- 1028968//National Science Foundation (NSF)/ ; CBET-1804118//National Science Foundation (NSF)/ ; CBET-1804118//National Science Foundation (NSF)/ ; CBET-1804118//National Science Foundation (NSF)/ ; CBET-1804118//National Science Foundation (NSF)/ ; }, abstract = {Reductions in nonresidential water demand during the COVID-19 pandemic highlighted the importance of understanding how water age impacts drinking water quality and microbiota in piped distribution systems. Using benchtop model distribution systems, we aimed to characterize the impacts of elevated water age on microbiota in bulk water and pipe wall biofilms. Five replicate constant-flow reactors were fed with municipal chloraminated tap water for 6 months prior to building closures and 7 months after. After building closures, chloramine levels entering the reactors dropped; in the reactor bulk water and biofilms the mean cell counts and ATP concentrations increased over an order of magnitude while the detection of opportunistic pathogens remained low. Water age, and the corresponding physicochemical changes, strongly influenced microbial abundance and community composition. Differential initial microbial colonization also had a lasting influence on microbial communities in each reactor (i.e., historical contingency).}, } @article {pmid38252999, year = {2024}, author = {Chosy, MB and Sun, J and Rahn, HP and Liu, X and Brčić, J and Wender, PA and Cegelski, L}, title = {Vancomycin-Polyguanidino Dendrimer Conjugates Inhibit Growth of Antibiotic-Resistant Gram-Positive and Gram-Negative Bacteria and Eradicate Biofilm-Associated S. aureus.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00168}, pmid = {38252999}, issn = {2373-8227}, abstract = {The global challenge of antibiotic resistance necessitates the introduction of more effective antibiotics. Here we report a potentially general design strategy, exemplified with vancomycin, that improves and expands antibiotic performance. Vancomycin is one of the most important antibiotics in use today for the treatment of Gram-positive infections. However, it fails to eradicate difficult-to-treat biofilm populations. Vancomycin is also ineffective in killing Gram-negative bacteria due to its inability to breach the outer membrane. Inspired by our seminal studies on cell penetrating guanidinium-rich transporters (e.g., octaarginine), we recently introduced vancomycin conjugates that effectively eradicate Gram-positive biofilm bacteria, persister cells and vancomycin-resistant enterococci (with V-r8, vancomycin-octaarginine), and Gram-negative pathogens (with V-R, vancomycin-arginine). Having shown previously that the spatial array (linear versus dendrimeric) of multiple guanidinium groups affects cell permeation, we report here for the first time vancomycin conjugates with dendrimerically displayed guanidinium groups that exhibit superior efficacy and breadth, presenting the best activity of V-r8 and V-R in single broad-spectrum compounds active against ESKAPE pathogens. Mode-of-action studies reveal cell-surface activity and enhanced vancomycin-like killing. The vancomycin-polyguanidino dendrimer conjugates exhibit no acute mammalian cell toxicity or hemolytic activity. Our study introduces a new class of broad-spectrum vancomycin derivatives and a general strategy to improve or expand antibiotic performance through combined mode-of-action and function-oriented design studies.}, } @article {pmid38252794, year = {2024}, author = {Zou, Y and Li, X and Mao, Y and Song, W and Liu, Q}, title = {Enhanced Biofilm Formation by Tetracycline in a Staphylococcus aureus Naturally Lacking ica Operon and atl.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {}, number = {}, pages = {}, doi = {10.1089/mdr.2023.0186}, pmid = {38252794}, issn = {1931-8448}, abstract = {Staphylococcus aureus is a major, widespread pathogen, and its biofilm-forming characteristics make it even more difficult to eliminate by biocides. Tetracycline (TCY) is a major broad-spectrum antibiotic, the residues of which can cause deleterious health impacts, and subinhibitory concentrations of TCY have the potential to increase biofilm formation in S. aureus. In this study, we showed how the biofilm formation of S. aureus 123786 is enhanced in the presence of TCY at specific subinhibitory concentrations. S. aureus 123786 used in this study was identified as Staphylococcal Cassette Chromosome mec III, sequence type239 and naturally lacking ica operon and atl gene. Two assays were performed to quantify the formation of S. aureus biofilm. In the crystal violet (CV) assay, the absorbance values of biofilm stained with CV at optical density (OD)540 nm increased after 8 and 16 hr of incubation when the concentration of TCY was 1/2 minimum inhibitory concentration (MIC), whereas at the concentration of 1/16 MIC, the absorbance values increased after 16 and 24 hr of incubation. In tetrazolium salt reduction assay, the absorbance value at OD490 nm of S. aureus 123786 biofilms mixed with 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium solution increased after 8 hr when the concentration of TCY was 1/4 MIC, which may be correlated with the higher proliferation and maturation of biofilm. In conclusion, the biofilm formation of S. aureus 123786 could be enhanced in the presence of TCY at specific subinhibitory concentrations.}, } @article {pmid38252349, year = {2024}, author = {Musafer, HK and Hussein, NH and Kareem, SM}, title = {Neonatal intensive care units: extended spectrum β-lactamase genes and biofilm formation by Serratia marcescens.}, journal = {Molecular biology reports}, volume = {51}, number = {1}, pages = {167}, pmid = {38252349}, issn = {1573-4978}, abstract = {BACKGROUND: The increasing cases of bloodstream infections among children at neonatal intensive care units (NICUs) led this work to investigate biofilm production, antibiotics and the presence of ESβL genes in Serratia marcescens (S. marcescens) strains isolated from blood.

METHODS: Twenty S. marcescens strains were isolated and identified by the VITEK-2 system over 7 months from late 2022 to mid-2023 from Ibn Al-Balady Hospital in Baghdad. Kirby-Bauer test was used to measure antibiotic susceptibility.

RESULTS: The results revealed that 95% of twenty S. marcescens isolates were non-susceptible to Ampicillin and Amoxicillin-clavulanic. Furthermore, S. marcescens isolates showed a high sensitivity rate 70% toward Imipenem. All S. marcescens strains 100% were produced biofilm. This work clarifies that, out of 20 S. marcescens strains, 80% were harbored ESβL genes. The coexistence of blaTEM, blaCTX and blaSHV genes was shown in 43.75% of strains, while 56.25% of S. marcescens strains harbored single ES[Formula: see text]L genes. The biofilm values increase with the accuracy of EsβL genes. Phylogenetic analyses based on the sequence of blaCTX-M and blaTEM were done with closely related genes in the GenBank using MEGA6 software.

CONCLUSIONS: The distribution of blaTEM, blaCTX and blaSHV genes among local S. marcescens strains may be attributed to the indiscriminate use of antibiotics. The results confirmed the spread of ESβL genes in S. marcescens from blood infections among newborn infants.}, } @article {pmid38252324, year = {2024}, author = {Chen, DZ and Qiu, J and Sun, H and Liu, Y and Ye, J and Chen, JM and Lu, L}, title = {Enhanced chlorobenzene removal by internal magnetic field through initial cell adhesion and biofilm formation.}, journal = {Applied microbiology and biotechnology}, volume = {108}, number = {1}, pages = {159}, pmid = {38252324}, issn = {1432-0614}, support = {2022YFC3702000//National Key Research and Development Program of China/ ; 52070169//National Natural Science Foundation of China/ ; 2022C41013//Project of Bureau of Science and Technology of Zhoushan/ ; }, abstract = {Magnetic fields (MF) have been proven efficient in bioaugmentation, and the internal MFs have become competitive because they require no configuration, despite their application in waste gas treatment remaining largely unexplored. In this study, we firstly developed an intensity-regulable bioaugmentation with internal MF for gaseous chlorobenzene (CB) treatment with modified packing in batch bioreactors, and the elimination capacity increased by up to 26%, surpassing that of the external MF. Additionally, the microbial affinity to CB and the packing surface was enhanced, which was correlated with the ninefold increased secreted ratio of proteins/polysaccharides, 43% promoted cell surface hydrophobicity, and half reduced zeta potential. Furthermore, the dehydrogenase content was promoted over 3 times, and CB removal steadily increased with the rising intensity indicating enhanced biofilm activity and reduced CB bioimpedance; this was further supported by kinetic analysis, which resulted in improved cell adhesive ability and biological utilisation of CB. The results introduced a novel concept of adjustable magnetic bioaugmentation and provided technical support for industrial waste gas treatments. KEY POINTS: • Regulable magnetic bioaugmentation was developed to promote 26% chlorobenzene removal • Chlorobenzene mineralisation was enhanced under the magnetic field • Microbial adhesion was promoted through weakening repulsive forces.}, } @article {pmid38251383, year = {2024}, author = {Kaushik, A and Kest, H and Sood, M and Steussy, BW and Thieman, C and Gupta, S}, title = {Biofilm Producing Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in Humans: Clinical Implications and Management.}, journal = {Pathogens (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, doi = {10.3390/pathogens13010076}, pmid = {38251383}, issn = {2076-0817}, abstract = {Since its initial description in the 1960s, methicillin-resistant Staphylococcus aureus (MRSA) has developed multiple mechanisms for antimicrobial resistance and evading the immune system, including biofilm production. MRSA is now a widespread pathogen, causing a spectrum of infections ranging from superficial skin issues to severe conditions like osteoarticular infections and endocarditis, leading to high morbidity and mortality. Biofilm production is a key aspect of MRSA's ability to invade, spread, and resist antimicrobial treatments. Environmental factors, such as suboptimal antibiotics, pH, temperature, and tissue oxygen levels, enhance biofilm formation. Biofilms are intricate bacterial structures with dense organisms embedded in polysaccharides, promoting their resilience. The process involves stages of attachment, expansion, maturation, and eventually disassembly or dispersion. MRSA's biofilm formation has a complex molecular foundation, involving genes like icaADBC, fnbA, fnbB, clfA, clfB, atl, agr, sarA, sarZ, sigB, sarX, psm, icaR, and srtA. Recognizing pivotal genes for biofilm formation has led to potential therapeutic strategies targeting elemental and enzymatic properties to combat MRSA biofilms. This review provides a practical approach for healthcare practitioners, addressing biofilm pathogenesis, disease spectrum, and management guidelines, including advances in treatment. Effective management involves appropriate antimicrobial therapy, surgical interventions, foreign body removal, and robust infection control practices to curtail spread within healthcare environments.}, } @article {pmid38249645, year = {2024}, author = {Motevasel, M and Haghkhah, M and Azimzadeh, N}, title = {Phylogenetic Aspects of Antibiotic Resistance and Biofilm Formation of P. aeruginosa Isolated from Clinical Samples.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2024}, number = {}, pages = {6213873}, pmid = {38249645}, issn = {1712-9532}, abstract = {INTRODUCTION: Biofilm production and drug resistance phenomenon play a critical role in P. aeruginosa infections. Several genes, including psl, pel, brlR, and mex, are involved in the phenomenon. The aim of this study was to find the relationship between the mentioned genes and the sources of P. aeruginosa infections.

MATERIALS AND METHODS: Fifty-nine P. aeruginosa isolates detected from clinical specimens were used to determine antibiotic susceptibility patterns, prevalence of the genes using PCR, biofilm formation, biofilm eradication concentration assay (MBEC), and epidemiological characteristics using pulsed-field gel electrophoresis (PFGE).

RESULTS: The results showed that 35.6% and 16.94% of all the samples were isolated from urine and wounds, 81.33% of the isolates were biofilm producers, 27.11% were multidrug-resistant (MDR), and 100% of the main biofilm former genes belonged to pslA. 94.91% of the isolates possessed brlR and mexA, and 91.5% of them expressed pslA. It was also indicated that neither ciprofloxacin nor imipenem could eradicate the formed biofilms. Moreover, we could identify 81.4% distinctive restriction profiles among the isolates, using an 80% similarity cutoff point; brlR and pel genes were significantly (P=0.032; P=0.044) related to phylogenetic pulsotypes. Comparison of the dendrogram in the isolates revealed that the detected isolates from urine were present in 12 different pulsotypes.

CONCLUSION: It was found that there was a relationship between MDR, biofilm production, and brlR and pel genes among the isolates. It is distinguished there were similar genetic patterns between detected isolates from urine and could be concluded that the urinary tract played a critical role in maintaining and transferring biofilm drug-resistant genes of P. aeruginosa in clinical sites. The study highlights the importance of urine in distribution of clinical biofilm formation and drug-resistant P. aeruginosa isolates.}, } @article {pmid38247639, year = {2024}, author = {Imparato, M and Maione, A and Buonanno, A and Gesuele, R and Gallucci, N and Corsaro, MM and Paduano, L and Casillo, A and Guida, M and Galdiero, E and de Alteriis, E}, title = {Extracellular Vesicles from a Biofilm of a Clinical Isolate of Candida albicans Negatively Impact on Klebsiella pneumoniae Adherence and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, doi = {10.3390/antibiotics13010080}, pmid = {38247639}, issn = {2079-6382}, abstract = {The opportunistic human fungal pathogen Candida albicans produces and releases into the surrounding medium extracellular vesicles (EVs), which are involved in some processes as communication between fungal cells and host-pathogen interactions during infection. Here, we have conducted the isolation of EVs produced by a clinical isolate of C. albicans during biofilm formation and proved their effect towards the ability of the Gram-negative bacterial pathogen Klebsiella pneumoniae to adhere to HaCaT cells and form a biofilm in vitro. The results represent the first evidence of an antagonistic action of fungal EVs against bacteria.}, } @article {pmid38247634, year = {2024}, author = {Coandă, M and Limban, C and Nuță, DC}, title = {Small Schiff Base Molecules-A Possible Strategy to Combat Biofilm-Related Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, doi = {10.3390/antibiotics13010075}, pmid = {38247634}, issn = {2079-6382}, abstract = {Microorganisms participating in the development of biofilms exhibit heightened resistance to antibiotic treatment, therefore infections involving biofilms have become a problem in recent years as they are more difficult to treat. Consequently, research efforts are directed towards identifying novel molecules that not only possess antimicrobial properties but also demonstrate efficacy against biofilms. While numerous investigations have focused on antimicrobial capabilities of Schiff bases, their potential as antibiofilm agents remains largely unexplored. Thus, the objective of this article is to present a comprehensive overview of the existing scientific literature pertaining to small molecules categorized as Schiff bases with antibiofilm properties. The survey involved querying four databases (Web of Science, ScienceDirect, Scopus and Reaxys). Relevant articles published in the last 10 years were selected and categorized based on the molecular structure into two groups: classical Schiff bases and oximes and hydrazones. Despite the majority of studies indicating a moderate antibiofilm potential of Schiff bases, certain compounds exhibited a noteworthy effect, underscoring the significance of considering this type of molecular modeling when seeking to develop new molecules with antibiofilm effects.}, } @article {pmid38247615, year = {2024}, author = {Weawsiangsang, S and Rattanachak, N and Ross, S and Ross, GM and Baldock, RA and Jongjitvimol, T and Jongjitwimol, J}, title = {Hydroquinine Enhances the Efficacy of Contact Lens Solutions for Inhibiting Pseudomonas aeruginosa Adhesion and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, doi = {10.3390/antibiotics13010056}, pmid = {38247615}, issn = {2079-6382}, abstract = {P. aeruginosa is one of the most common bacteria causing contact lens-related microbial keratitis (CLMK). Previous studies report that disinfecting solutions were ineffective in preventing biofilm formation. Solutions containing novel natural agents may be an excellent alternative for reducing the risk of CLMK. Here, we investigate the disinfecting properties of hydroquinine in combination with multipurpose solutions (MPSs) to prevent P. aeruginosa adhesion and biofilm formation. We examined the antibacterial, anti-adhesion, and anti-biofilm properties of hydroquinine-formulated MPSs compared to MPSs alone. Using RT-qPCR, hydroquinine directly affected the expression levels of adhesion-related genes, namely, cgrC, cheY, cheZ, fimU, and pilV, resulting in reduced adhesion and anti-biofilm formation. Using ISO 14729 stand-alone testing, hydroquinine met the criteria (>99.9% killing at disinfection time) against both P. aeruginosa reference and clinical strains. Using the crystal violet retention assay and FE-SEM, MPSs combined with hydroquinine were effective in inhibiting P. aeruginosa adhesion and destroying preexisting biofilms. This report is the first to highlight the potential utility of hydroquinine-containing formulations as a disinfecting solution for contact lenses, specifically for inhibiting adhesion and destroying biofilm. These findings may aid in the development of novel disinfectants aimed at combating P. aeruginosa, thereby potentially reducing the incidence of CLMK.}, } @article {pmid38246090, year = {2024}, author = {Oschmann-Kadenbach, AM and Schaudinn, C and Borst, L and Schwarz, C and Konrat, K and Arvand, M and Lewin, A}, title = {Impact of Mycobacteroides abscessus colony morphology on biofilm formation and antimicrobial resistance.}, journal = {International journal of medical microbiology : IJMM}, volume = {314}, number = {}, pages = {151603}, doi = {10.1016/j.ijmm.2024.151603}, pmid = {38246090}, issn = {1618-0607}, abstract = {Mycobacteroides abscessus is one of the most resistant bacteria so far known and causes severe and hard to treat lung infections in predisposed patients such as those with Cystic Fibrosis (CF). Further, it causes nosocomial infections by forming biofilms on medical devices or water reservoirs. An eye-catching feature of M. abscessus is the growth in two colony morphotypes. Depending on the presence or absence of glycopeptidolipids on the cell surface, it forms smooth or rough colonies. In this study, a porous glass bead biofilm model was used to compare biofilm formation, biofilm organization and biofilm matrix composition in addition to the antimicrobial susceptibility of M. abscessus biofilms versus suspensions of isogenic (smooth and rough) patient isolates. Both morphotypes reached the same cell densities in biofilms. The biofilm architecture, however, was dramatically different with evenly distributed oligo-layered biofilms in smooth isolates, compared to tightly packed, voluminous biofilm clusters in rough morphotypes. Biofilms of both morphotypes contained more total biomass of the matrix components protein, lipid plus DNA than was seen in corresponding suspensions. The biofilm mode of growth of M. abscessus substantially increased resistance to the antibiotics amikacin and tigecycline. Tolerance to the disinfectant peracetic acid of both morphotypes was increased when grown as biofilm, while tolerance to glutaraldehyde was significantly increased in biofilm of smooth isolates only. Overall, smooth colony morphotypes had more pronounced antimicrobial resistance benefit when growing as biofilm than M. abscessus showing rough colony morphotypes.}, } @article {pmid38245708, year = {2024}, author = {Pan, J and Singh, A and Hanning, K and Hicks, J and Williamson, A}, title = {A role for the ATP-dependent DNA ligase lig E of Neisseria gonorrhoeae in biofilm formation.}, journal = {BMC microbiology}, volume = {24}, number = {1}, pages = {29}, pmid = {38245708}, issn = {1471-2180}, support = {21/754//Health Research Council of New Zealand/ ; 23/534//Health Research Council of New Zealand/ ; 20-UOW-004//Rutherford Discovery Fellowship/ ; }, mesh = {Humans ; DNA Ligase ATP/genetics ; *Neisseria gonorrhoeae/genetics/metabolism ; *DNA Ligases/genetics/chemistry/metabolism ; DNA ; Biofilms ; }, abstract = {BACKGROUND: The ATP-dependent DNA ligase Lig E is present as an accessory DNA ligase in numerous proteobacterial genomes, including many disease-causing species. Here we have constructed a genomic Lig E knock-out in the obligate human pathogen Neisseria gonorrhoeae and characterised its growth and infection phenotype.

RESULTS: This demonstrates that N. gonorrhoeae Lig E is a non-essential gene and its deletion does not cause defects in replication or survival of DNA-damaging stressors. Knock-out strains were partially defective in biofilm formation on an artificial surface as well as adhesion to epithelial cells. In addition to in vivo characterisation, we have recombinantly expressed and assayed N. gonorrhoeae Lig E and determined the crystal structure of the enzyme-adenylate engaged with DNA substrate in an open non-catalytic conformation.

CONCLUSIONS: These findings, coupled with the predicted extracellular/ periplasmic location of Lig E indicates a role in extracellular DNA joining as well as providing insight into the binding dynamics of these minimal DNA ligases.}, } @article {pmid38245627, year = {2024}, author = {Sharma, A and Rashid, M and Chauhan, P and Kaur, S and Kaur, A}, title = {In vitro antibacterial and anti-biofilm potential of an endophytic Schizophyllum commune.}, journal = {AMB Express}, volume = {14}, number = {1}, pages = {10}, pmid = {38245627}, issn = {2191-0855}, abstract = {The emergence of antibiotic resistance in pathogens is one of the major health concerns facing mankind as different bacterial strains have developed resistance to antibiotics over the period of time due to overuse and misuse of antibiotics. Besides this, ability to form biofilms is another major factor contributing to antibiotic resistance, which has necessitated the need for exploration for novel and effective compounds with ability to inhibit biofilm formation. Endophytic fungi are reported to exhibit antibacterial and anti-biofilm potential and could serve as a potent source of novel antibacterial compounds. Majority of the bioactivities have been reported from fungi belonging to phylum Ascomycota. Endophytic basidiomycetes, inspite of their profound ability to serve as a source of bioactive compounds have not been exploited extensively. In present study, an attempt was made to assess the antibacterial, anti-biofilm and biofilm dispersion potential of an endophytic basidiomycetous fungus Schizophyllum commune procured from the culture collection of our lab. Ethyl acetate extract of S. commune showed good antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica and Vibrio cholerae. Minimum inhibitory concentration and minimum bactericidal concentration of the extract were in the range of 1.25-10 mg/ml against the tested bacterial pathogens. The mode of action was determined to be bactericidal which was further confirmed by time kill studies. Good anti-biofilm activity of S. commune extract was recorded against K. pneumoniae and S. enterica, which was further validated by fluorescence microscopy. The present study highlights the importance of endophytic basidiomycetes as source of therapeutic compounds.}, } @article {pmid38245549, year = {2024}, author = {Gómez-Alonso, IS and Betanzos-Cabrera, G and Moreno-Lafont, MC and Cancino-Diaz, ME and García-Pérez, BE and Cancino-Diaz, JC}, title = {Non-biofilm-forming Staphylococcus epidermidis planktonic cell supernatant induces alterations in osteoblast biological function.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {1807}, pmid = {38245549}, issn = {2045-2322}, abstract = {Staphylococcal biofilms significantly contribute to prosthetic joint infection (PJI). However, 40% of S. epidermidis PJI isolates do not produce biofilms, which does not explain the role of biofilms in these cases. We studied whether the supernatant from planktonic S. epidermidis alters osteoblast function. Non-biofilm-forming S. epidermidis supernatants (PJI[-] clinical isolate, healthy skin isolate (HS), and ATCC12228 reference strain) and biofilm-forming supernatants (PJI[+] clinical isolate, ATCC35984 reference strain, and Staphylococcus aureus USA300 reference strain) were included. Osteoblasts stimulated with supernatants from non-biofilm-forming isolates for 3, 7, and 14 days showed significantly reduced cellular DNA content compared with unstimulated osteoblasts, and apoptosis was induced in these osteoblasts. Similar results were obtained for biofilm-forming isolates, but with a greater reduction in DNA content and higher apoptosis. Alkaline phosphatase activity and mineralization were significantly reduced in osteoblasts treated with supernatants from non-biofilm-forming isolates compared to the control at the same time points. However, the supernatants from biofilm-forming isolates had a greater effect than those from non-biofilm-forming isolates. A significant decrease in the expression of ATF4, RUNX2, ALP, SPARC, and BGLAP, and a significant increase in RANK-L expression were observed in osteoblasts treated with both supernatants. These results demonstrate that the supernatants of the S. epidermidis isolate from the PJI[-] and HS (commensal) with a non-biofilm-forming phenotype alter the function of osteoblasts (apoptosis induction, failure of cell differentiation, activation of osteoblasts, and induction of bone resorption), similar to biofilm-forming isolates (PJI[+], ATCC35984, and S. aureus USA300), suggesting that biofilm status contributes to impaired osteoblast function and that the planktonic state can do so independently of biofilm production.}, } @article {pmid38244636, year = {2024}, author = {Cai, Y and Dong, J and Huang, J and He, J and Hu, Y and Sui, Z and Tang, P}, title = {The cyclic AMP (cAMP) phosphodiesterase CpdA required for growth, biofilm formation, motility and pathogenicity of Edwardsiella piscicida.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106545}, doi = {10.1016/j.micpath.2024.106545}, pmid = {38244636}, issn = {1096-1208}, abstract = {Edwardsiella piscicida is a severe fish pathogen with wide host range, causing the huge economic losses in the aquaculture industry. Cyclic adenosine monophosphate (cAMP) as an important second messenger regulates the physiological and behavioral responses to environmental cues in eukaryotic and prokaryotic. The intracellular level of cAMP for effective activity is tightly controlled by the synthesis of adenylate cyclase, excretion and degradation of phosphodiesterase. In this study, we identified and characterized a class III cAMP phosphodiesterase, named as CpdA, in the E. piscicida. To investigate the role of CpdA in the physiology and pathogenicity, we constructed the in-frame deletion mutant of cpdA of E. piscicida, TX01ΔcpdA. The results showed that TX01ΔcpdA accumulated the higher intracellular cAMP concentration than TX01, indicating that CpdA exerted the hydrolysis of cAMP. In addition, compared to the TX01, the TX01ΔcpdA slowed growth rate, diminished biofilm formation and lost motility. More importantly, pathogenicity analysis confirmed that TX01ΔcpdA significantly impaired the ability of invading the epithelial cells, reproduction in macrophages, tissues dissemination and lethality for healthy tilapias. The most of lost properties of TX01ΔcpdA were restored partially or fully by the introduction of cpdA gene. These results suggest that cpdA is required for regulation of the physiology and virulence of E. piscicida.}, } @article {pmid38244634, year = {2024}, author = {Zhang, J and Huang, L and Wang, Y}, title = {Changes in the level of biofilm development significantly affect the persistence of environmental DNA in flowing water.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {170162}, doi = {10.1016/j.scitotenv.2024.170162}, pmid = {38244634}, issn = {1879-1026}, abstract = {As one of the powerful tools of species biomonitoring, the utilization of environmental DNA (eDNA) technology is progressively expanding in both scope and frequency within the field of ecology. Nonetheless, the growing dissemination of this technology has brought to light a multitude of intricate issues. The complex effects of environmental factors on the persistence of eDNA in water have brought many challenges to the interpretation of eDNA information. In this study, the primary objective was to examine how variations in the presence and development of biofilms impact the persistence of grass carp eDNA under different sediment types and flow conditions. This investigation encompassed the processes of eDNA removal and resuspension in water, shedding light on the complex interactions involved. The findings reveal that with an elevated biofilm development level, the total removal rate of eDNA gradually rose, resulting in a corresponding decrease in its residence time within the mesocosms. The influence of biofilms on the persistence of grass carp eDNA is more pronounced under flowing water conditions. However, changes in bottom sediment types did not significantly interact with biofilms. Lastly, in treatments involving alternating flow conditions between flowing and still water, significant resuspension of grass carp eDNA was not observed due to interference from multiple factors, including the effect of biofilms. Our study offers preliminary insights into the biofilm-mediated mechanisms of aquatic eDNA removal, emphasizing the need for careful consideration of environmental factors in the practical application of eDNA technology for biomonitoring in real aquatic environments.}, } @article {pmid38239503, year = {2023}, author = {Wang, LL and Huang, SJ and Zhao, JT and Liu, JY and Xiang, MJ}, title = {Regulatory role of Mss11 in Candida glabrata virulence: adhesion and biofilm formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1321094}, pmid = {38239503}, issn = {2235-2988}, abstract = {INTRODUCTION: Candida glabrata has emerged as a fungal pathogen with high infection and mortality rates, and its primary virulence factors are related to adhesion and biofilm formation. These virulence factors in C.glabrata are primarily mediated by epithelial adhesins (Epas), most of which are encoded in subtelomeric regions and regulated by subtelomeric silencing mechanisms. The transcription factor Mss11, known for its regulatory role in adhesion, biofilm formation, and filamentous growth in Saccharomyces cerevisiae and Candida albicans, has also been implicated in the expression of EPA6, suggesting its potential influence on C.glabrata virulence. The present study aims to determine the regulatory role of Mss11 in the virulence of C. glabrata.

METHODS: In this work, a Δmss11 null mutant and its complemented strain were constructed from a C.glabrata standard strain. The impact of the transcription factor Mss11 on the virulence of C.glabrata was investigated through a series of phenotypic experiments, including the microbial adhesion to hydrocarbons (MATH) test, adherence assay, biofilm assay, scanning electron microscopy and Galleria mellonella virulence assay. Furthermore, transcriptome sequencing, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation sequencing (ChIP-seq) were employed to investigate the molecular mechanisms behind the regulation of Mss11.

RESULTS: In C.glabrata, the loss of MSS11 led to a significant reduction in several virulence factors including cell surface hydrophobicity, epithelial cell adhesion, and biofilm formation. These observations were consistent with the decreased virulence of the Δmss11 mutant observed in the Galleria mellonella infection model. Further exploration demonstrated that Mss11 modulates C. glabrata virulence by regulating EPA1 and EPA6 expression. It binds to the upstream regions of EPA1 and EPA6, as well as the promoter regions of the subtelomeric silencing-related genes SIR4, RIF1, and RAP1, indicating the dual regulatory role of Mss11.

CONCLUSION: Mss11 plays a crucial role in C. glabrata adhesion and biofilm formation, and thus has a broad influence on virulence. This regulation is achieved by regulating the expression of EPA1 and EPA6 through both promoter-specific regulation and subtelomeric silencing.}, } @article {pmid38239025, year = {2023}, author = {Thoulouze, MI and Inizan, C}, title = {[What about a transmission of SARS-CoV-2 through a viral biofilm?].}, journal = {Virologie (Montrouge, France)}, volume = {27}, number = {6}, pages = {313-316}, doi = {10.1684/vir.2023.1027}, pmid = {38239025}, issn = {1267-8694}, } @article {pmid38239024, year = {2023}, author = {Thoulouze, MI and Inizan, C}, title = {[Et si le SARS-CoV-2 se transmettait sous forme de biofilm viral ?].}, journal = {Virologie (Montrouge, France)}, volume = {27}, number = {6}, pages = {85-88}, doi = {10.1684/vir.2023.1029}, pmid = {38239024}, issn = {1267-8694}, } @article {pmid38237678, year = {2024}, author = {Eilers, K and Hoong Yam, JK and Liu, X and Goh, YF and To, K and Paracuellos, P and Morton, R and Brizuela, J and Hui Yong, AM and Givskov, M and Freibert, SA and Bange, G and Rice, SA and Steinchen, W and Filloux, A}, title = {The dual GGDEF/EAL domain enzyme PA0285 is a Pseudomonas species housekeeping phosphodiesterase regulating early attachment and biofilm architecture.}, journal = {The Journal of biological chemistry}, volume = {}, number = {}, pages = {105659}, doi = {10.1016/j.jbc.2024.105659}, pmid = {38237678}, issn = {1083-351X}, abstract = {Bacterial lifestyles depend on conditions encountered during colonization. The transition between planktonic and biofilm growth is dependent on the intracellular second messenger c-di-GMP. High c-di-GMP levels driven by diguanylate cyclases (DGC) activity favor biofilm formation, while low levels maintained by phosphodiesterases (PDE) encourage planktonic lifestyle. The activity of these enzymes can be modulated by stimuli-sensing domains such as PAS. In Pseudomonas aeruginosa, more than 40 PDE/DGC are involved in c-di-GMP homeostasis, including 16 dual proteins possessing both canonical DGC and PDE motifs, i.e., GGDEF and EAL, respectively. It was reported that deletion of the EAL/GGDEF dual enzyme PA0285, one of five c-di-GMP-related enzymes conserved across all Pseudomonas species, impacts biofilms. PA0285 is anchored in the membrane and carries two PAS domains. Here we confirm that its role is conserved in various P. aeruginosa strains and in Pseudomonas putida. Deletion of PA0285 impacts the early stage of colonization, and RNA-seq analysis suggests that expression of cupA fimbrial genes is involved. We demonstrate that the C-terminal portion of PA0285 encompassing the GGDEF and EAL domains binds GTP and c-di-GMP, respectively, but only exhibits PDE activity in vitro. However, both GGDEF and EAL domains are important for PA0285 PDE activity in vivo. Complementation of the PA0285 mutant strain with a copy of the gene encoding the C-terminal GGDEF/EAL portion in trans was not as effective as complementation with the full-length gene. This suggests the N-terminal transmembrane and PAS domains influence the PDE activity in vivo, through modulating the protein conformation.}, } @article {pmid38235811, year = {2023}, author = {Kannappan, K and Chaly, PE and Sivasamy, S}, title = {Effect of frequent exposures of various indigenous sugars on cariogenicity of a biofilm caries model.}, journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry}, volume = {41}, number = {4}, pages = {267-273}, doi = {10.4103/jisppd.jisppd_335_23}, pmid = {38235811}, issn = {1998-3905}, mesh = {Humans ; *Tooth Demineralization ; Sugars ; Dental Caries Susceptibility ; *Dental Caries ; Sucrose/adverse effects ; Biofilms ; }, abstract = {AIM: The aim of this study was to assess and compare the cariogenicity of indigenous sugars (palm sugar, jaggery, and brown sugar) and refined sugar at different frequencies of exposure through a biofilm caries model.

METHODOLOGY: This in vitro study was conducted on 60 extracted human premolar teeth which were randomly divided into four groups (refined sugar, jaggery, palm sugar, and brown sugar) with each group being exposed to their respective sugars at one, three, and five frequencies for 5 min at defined time periods with five sample teeth for each exposure (4 × 3 × 5 = 60). The acidogenicity of biofilm was found by a 5-day pH cycling model. After 5 days, enamel demineralization, protein content, and polysaccharide formation of the biofilm following exposure to various sugars at various frequencies were assessed and compared. Statistical analyses were done using a one-way analysis of variance for intergroup comparisons between various sugars at various levels of frequencies.

RESULTS: The enamel demineralization was found to be least in palm sugar with mean percentage surface hardness loss of 8%, 17%, and 25% at one, three, and five frequencies of exposures and this was found to be statistically significant compared to other sugars (P < 0.001). The acidogenicity of biofilm increased with an increase in the frequency of exposures, but none of the indigenous sugars had a drop below 5.5 (critical pH) at a single frequency of exposure indicating less acid production at minimal exposure. The protein content of the biofilm exposed to palm sugar was less on comparison with other sugars and it was found to be statistically significant (P < 0.001). The polysaccharide formation of all sugars was similar at each frequency of exposure and was statistically nonsignificant.

CONCLUSION: From the results obtained, it was concluded that though cariogenicity increased in all sugars with an increase in frequency of exposure, the level of cariogenicity was least in palm sugar compared to other sugars used in the study. Hence, it is recommended to use palm sugar as an alternative to refined sugar.}, } @article {pmid38234662, year = {2024}, author = {Ovchinnikov, E and Silanteva, T and Stogov, M and Diuriagina, O and Godovykh, N and Kubrak, N}, title = {Suppression of Staphylococcus aureus biofilm formation under a short-term impact of low-intensity direct current in vitro and in a rat model of implant-associated osteomyelitis.}, journal = {Iranian journal of basic medical sciences}, volume = {27}, number = {2}, pages = {247-255}, pmid = {38234662}, issn = {2008-3866}, abstract = {OBJECTIVES: We investigated the effect of short-term low-intensity direct current (LIDC) on Staphylococcus aureus.

MATERIALS AND METHODS: The reference strain of S. aureus was used. Experiments were performed in agar culture and on a model of rat's femur osteomyelitis. K-wires were used as electrodes. The exposure to LIDC of 150 μA continued for one minute. In vitro exposure was performed once. In vivo group 1 was a control group. Osteomyelitis was modeled in three groups but only groups 3 and 4 were exposed to LIDC four times: either from day 1 or from day 7 post-surgery. The effect was evaluated on day 21. Microbiological, histological, scanning electron, and light microscopy methods were used for evaluation of the LIDC effect.

RESULTS: Bacteria diameter, oblongness, and division increased 15 min after LIDC exposure in the culture around the cathode. After 24 hr, the amount of exomatrix was lower than in the control test, and the cell diameter and roundness increased. Similar changes around the anode were less pronounced. In vivo, biofilm formation on the intramedullary wire cathode was suppressed in group 3. In group 4, detachment and destruction of the biofilm were observed. The formation of S. aureus microcolonies was suppressed, and the adhesion of fibroblasts and immune cells was activated. LIDC did not stop the development of the osteomyelitis process.

CONCLUSION: Short-term exposure to LIDC suppresses S. aureus biofilm formation on the implant cathode surface in the acute and early postoperative period but does not have an impact on the development of osteomyelitis.}, } @article {pmid38234112, year = {2024}, author = {Somrani, M and Huertas, JP and Iguaz, A and Debbabi, H and Palop, A}, title = {Biofilm busters: Exploring the antimicrobial and antibiofilm properties of essential oils against Salmonella Enteritidis.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {}, number = {}, pages = {10820132241227004}, doi = {10.1177/10820132241227004}, pmid = {38234112}, issn = {1532-1738}, abstract = {This study delves into an exploration of the antimicrobial and antibiofilm properties of the essential oils (EOs) of cinnamon, garlic, and onion on Salmonella Enteritidis. Firstly, disc diffusion and minimum inhibitory concentration (MIC) techniques were employed to assess the antibacterial activity of the EOs. Additionally, the study explored the effect of these EOs on both initial cell attachment and 24 h-preformed biofilms. The crystal violet assay was implemented to evaluate biofilm biomass. The findings revealed that cinnamon EO exhibited the highest anti-biofilm activity. Furthermore, initial cell attachment inhibition at MIC ranged between 50 and 65% for the three oils, while inhibition rates on preformed structures were lower than 40% for all EOs at this MIC concentration. The study also found that the effects of these oils were dosage- and time-dependent (p < 0.05), thereby urging the adoption of these natural extracts as effective strategies for combating Salmonella biofilms.}, } @article {pmid38233257, year = {2024}, author = {Jia, P and Yang, J}, title = {Biofilm accumulation on complete arch subperiosteal implant-supported prostheses: Effect of pontic type.}, journal = {The Journal of prosthetic dentistry}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.prosdent.2023.12.015}, pmid = {38233257}, issn = {1097-6841}, abstract = {STATEMENT OF PROBLEM: Complete arch subperiosteal implant-supported prostheses present challenges in terms of effective cleaning, leading to the accumulation of biofilm on their intaglio surfaces. The association between different intaglio surface morphologies and biofilm accumulation on complete arch subperiosteal implant-supported prostheses is unclear.

PURPOSE: The purpose of this in vitro study was to investigate the correlation between the intaglio surface of complete arch subperiosteal implant-supported prostheses and biofilm accumulation.

MATERIAL AND METHODS: Sixty-eight complete arch subperiosteal implant-supported prostheses were fabricated with varying interimplant distances and pontic morphologies. Four different types of pontic morphologies were included: saddle, flat, scalloped, and ovate. To simulate biofilm accumulation, a green aerosol was sprayed onto the intaglio surface. Dental floss was used to clean the colored spray from the intaglio surface. The intaglio surfaces of prostheses were then scanned with an intraoral scanner. The biofilm areas were identified and calculated by using a 3-dimensional macroscopical quantification method. The distances between adjacent implants and transmucosal height were measured. The correlation between interimplant distances and biofilm areas, and the correlation between the biofilm areas and transmucosal height, were analyzed using the Spearman test. Furthermore, a generalized estimating equation (GEE) was employed to examine the relationship between pontic morphology and biofilm area, adjusting for location, cantilever, implant distance, and transmucosal height (α=.05).

RESULTS: A significant correlation was found between the biofilm area and transmucosal height (correlation coefficient=0.208, P<.001). A significant increase in biofilm accumulation was observed in the saddle group compared with the 3 groups in GEE Models I and II.

CONCLUSIONS: Flat pontics and ovate pontics have significantly lower biofilm retention. Moreover, transmucosal height plays a significant role in biofilm accumulation in the pontic area.}, } @article {pmid38232080, year = {2024}, author = {Kar, A and Mukherjee, SK and Barik, S and Hossain, ST}, title = {Antimicrobial Activity of Trigonelline Hydrochloride Against Pseudomonas aeruginosa and Its Quorum-Sensing Regulated Molecular Mechanisms on Biofilm Formation and Virulence.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00617}, pmid = {38232080}, issn = {2373-8227}, abstract = {Pseudomonas aeruginosa, a vivid biofilm-producing bacterium, is considered a dreadful opportunistic pathogen, and thus, management of biofilm-associated infections due to multidrug resistant strains by traditional drugs currently is of great concern. This study was aimed to assess the impact of trigonelline hydrochloride, a pyridine alkaloid, on P. aeruginosa PAO1, in search of an alternative therapeutant. The effect of trigonelline on colony morphology and motility was studied along with its role on biofilm and expression virulence factors. Trigonelline influenced the colony structure, motility, biofilm architecture, and the production of virulence factors in a dose-dependent manner. Alterations in quorum sending (QS)-regulated gene expression after treatment and molecular docking analysis for certain regulator proteins confirmed its effect on the QS-system network by affecting Las, Rhl, and Pqs signaling pathways and as possible molecular targets. Thus, trigonelline might be considered as a potential chemical lead to manage biofilm-associated pathogenesis or to develop other analogues with enhanced pharmacokinetic actions.}, } @article {pmid38231065, year = {2024}, author = {Masadeh, MM and Bany-Ali, NM and Khanfar, MS and Alzoubi, KH and Massadeh, MM and Almomani, EM}, title = {Synergistic Antibacterial Effect of ZnO Nanoparticles and Antibiotics against Multidrug-Resistant Biofilm Bacteria.}, journal = {Current drug delivery}, volume = {}, number = {}, pages = {}, doi = {10.2174/0115672018279213240110045557}, pmid = {38231065}, issn = {1875-5704}, abstract = {BACKGROUND: The misuse of antibiotics leads to a global increase in antibiotic resistance. Therefore, it is imperative to search for alternative compounds to conventional antibiotics. ZnO nanoparticles (Zn NP) are one of these alternatives because they are an effective option to overcome biofilm bacterial cells and a novel way to overcome multidrug resistance in bacteria. The current research study aims to characterize the efficacy of ZnO nanoparticles alone and in combination with other antibacterial drugs against bacterial biofilms.

METHODS: ZnO NPs were prepared by co-precipitation method, and their anti-biofilm and antibacterial activities alone or combined with four types of broad-spectrum antibacterial (Norfloxacin, Colistin, Doxycycline, and Ampicillin) were evaluated against E. coli and S. aureus bacterial strains. Finally, the cytotoxicity and the hemolytic activity were evaluated.

RESULTS: ZnO NPs were prepared, and results showed that their size was around 10 nm with a spherical shape and a zeta potential of -21.9. In addition, ZnO NPs were found to have a strong antibacterial effect against Gram-positive and Gram-negative microorganisms, with a minimum inhibitory concentration (MIC) of 62.5 and 125 μg/mL, respectively. Additionally, they could eradicate biofilmforming microorganisms at a concentration of 125 μg/m. ZnO NPs were found to be non-toxic to erythrocyte cells. Still, some toxicity was observed for Vero cells at effective concentration ranges needed to inhibit bacterial growth and eradicate biofilm-forming organisms. When combined with different antibacterial, ZnO NP demonstrated synergistic and additive effects with colistin, and the MIC and MBEC of the combination decreased significantly to 0.976 μg/mL against planktonic and biofilm strains of MDR Gram-positive bacteria, resulting in significantly reduced toxicity.

CONCLUSION: The findings of this study encourage the development of alternative therapies with high efficacy and low toxicity. ZnO nanoparticles have demonstrated promising results in overcoming multi-drug resistant bacteria and biofilms, and their combination with colistin has shown a significant reduction in toxicity. Further studies are needed to investigate the potential of ZnO nanoparticles as a viable alternative to conventional antibiotics.}, } @article {pmid38230925, year = {2024}, author = {Yousefi Nojookambari, N and Eslami, G and Sadredinamin, M and Vaezjalali, M and Nikmanesh, B and Dehbanipour, R and Yazdansetad, S and Ghalavand, Z}, title = {Sub-minimum inhibitory concentrations (sub-MICs) of colistin on Acinetobacter baumannii biofilm formation potency, adherence, and invasion to epithelial host cells: an experimental study in an Iranian children's referral hospital.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0252323}, doi = {10.1128/spectrum.02523-23}, pmid = {38230925}, issn = {2165-0497}, abstract = {Since the toxicity of colistin is dose dependent, there is a focus on strategies that reduce the dose while maintaining the therapeutic effect of the drug. Our findings about sub-inhibitory doses of colistin provide a novel insight into the logical use of colistin to treat and control Acinetobacter baumannii-related infections in clinical practice.}, } @article {pmid38230455, year = {2024}, author = {Abulimiti, A and Qi-Ao, Z and Pei-Bo, L and Jian-Ping, X}, title = {Regulation of Mycobacterium biofilm development and novel measures against antibiotics resistance.}, journal = {Yi chuan = Hereditas}, volume = {46}, number = {1}, pages = {34-45}, doi = {10.16288/j.yczz.23-205}, pmid = {38230455}, issn = {0253-9772}, abstract = {Currently, there are over 170 recognized species of Mycobacterium, the only genus in the family Mycobacteriaceae. Organisms belonging to this genus are quite diverse with respect to their ability to cause disease in humans. The Mycobacterium genus includes human pathogens (Mycobacterium tuberculosis complex and Mycobacterium leprae) and environmental microorganisms known as non-tuberculosis mycobacteria (NTM). A common pathogenic factor of Mycobacterium is the formation of biofilms. Bacterial biofilms are usually defined as bacterial communities attached to the surface, and are also considered as shared spaces of encapsulated microbial cells, including various extracellular polymeric substrates (EPS), such as polysaccharides, proteins, amyloid proteins, lipids, and extracellular DNA (EDNA), as well as membrane vesicles and humic like microorganisms derived refractory substances. The assembly and dynamics of the matrix are mainly coordinated by second messengers, signaling molecules, or small RNAs. Fully deciphering how bacteria provide structure for the matrix, thereby promoting extracellular reactions and benefiting from them, remains a challenge for future biofilm research. This review introduces a five step development model for biofilms and a new model for biofilm formation, analyses the pathogenicity of biofilms, their interactions with bacteriophages and host immune cells, and the key genes and regulatory networks of mycobacterial biofilms, as well as mycobacterial biofilms and drug resistance, in order to provide a basis for clinical treatment of diseases caused by biofilms.}, } @article {pmid38229564, year = {2024}, author = {Zhang, Y and Li, L and Liu, H and Zhang, H and Wei, M and Zhang, J and Yang, Y and Wu, M and Chen, Z and Liu, C and Wang, F and Wu, Q and Shi, J}, title = {Copper(II)-infused porphyrin MOF: maximum scavenging GSH for enhanced photodynamic disruption of bacterial biofilm.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb02577b}, pmid = {38229564}, issn = {2050-7518}, abstract = {Bacterial biofilm infection is a serious obstacle to clinical therapeutics. Photodynamic therapy (PDT) plays a dynamic role in combating biofilm infection by utilizing reactive oxygen species (ROS)-induced bacterial oxidation injury, showing advantages of mild side effects, spatiotemporal controllability and little drug resistance. However, superfluous glutathione (GSH) present in biofilm and bacteria corporately reduces ROS levels and seriously affects PDT efficiency. Herein, we have constructed a Cu[2+]-infused porphyrin metal-organic framework (MOF@Cu[2+]) for the enhanced photodynamic combating of biofilm infection by the maximum depletion of GSH. Our results show that the released Cu[2+] from porphyrin MOF@Cu[2+] could not only oxidize GSH in biofilm but also consume GSH leaked from ROS-destroyed bacteria, thus greatly weakening the antioxidant system in biofilm and bacteria and dramatically improving the ROS levels. As expected, our dual-enhanced PDT nanoplatform exhibits a strong biofilm eradication ability both in vitro and in an in vivo biofilm-infected mouse model. In addition, Cu[2+] can promote biofilm-infected wound closing by provoking cell immigration, collagen sediment and angiogenesis. Besides, no apparent toxicity was detected after treatment with MOF@Cu[2+]. Overall, our design offers a new paradigm for photodynamic combating biofilm infection.}, } @article {pmid38229003, year = {2024}, author = {Tan, J and Lamont, GJ and Scott, DA}, title = {Tobacco-enhanced biofilm formation by Porphyromonas gingivalis and other oral microbes.}, journal = {Molecular oral microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/omi.12450}, pmid = {38229003}, issn = {2041-1014}, support = {DE026963 DE017680 DE019826/DE/NIDCR NIH HHS/United States ; /NH/NIH HHS/United States ; }, abstract = {Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and, generally, fostering survival and persistence. Environmental fluxes are known to influence biofilm formation and composition, with recent data suggesting that tobacco and tobacco-derived stimuli are particularly important mediators of biofilm initiation and development in vitro and determinants of polymicrobial communities in vivo. The evidence for tobacco-augmented biofilm formation by oral bacteria, tobacco-induced oral dysbiosis, tobacco-resistance strategies, and bacterial physiology is summarized herein. A general overview is provided alongside specific insights gained through studies of the model and archetypal, anaerobic, Gram-negative oral pathobiont, Porphyromonas gingivalis.}, } @article {pmid38224336, year = {2024}, author = {Lin, Y and Ma, Q and Yan, J and Gong, T and Huang, J and Chen, J and Li, J and Qiu, Y and Wang, X and Lei, Z and Zeng, J and Wang, L and Zhou, X and Li, Y}, title = {Inhibition of Streptococcus mutans growth and biofilm formation through protein acetylation.}, journal = {Molecular oral microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/omi.12452}, pmid = {38224336}, issn = {2041-1014}, support = {32170046//National Natural Science Foundation of China/ ; 2022YFH0048//Sichuan Province Science and Technology Support Program/ ; 2021YFH0060//Sichuan Province Science and Technology Support Program/ ; 2021-YF05-01819-SN//Technological Innovation and Development Project of Chengdu Bureau of Science and Technology/ ; 2022KXK0403//State Key Laboratory of Oral Disease/ ; }, abstract = {Numerous cellular processes are regulated in response to the metabolic state of the cell, and one such regulatory mechanism involves lysine acetylation. Lysine acetylation has been proven to play an important role in the virulence of Streptococcus mutans, a major cariogenic bacterial species. S. mutans' glucosyltransferases (Gtfs) are responsible for synthesizing extracellular polysaccharides (EPS) and contributing to biofilm formation. One of the most common nonsteroidal anti-inflammatory drugs is acetylsalicylic acid (ASA), which can acetylate proteins through a nonenzymatic transacetylation reaction. Herein, we investigated the inhibitory effects of ASA on S. mutans. ASA treatment was observed to impede the growth of S. mutans, leading to a reduction in the production of water-insoluble EPS and the formation of biofilm. Moreover, ASA decreased the enzyme activity of Gtfs while increasing the protein acetylation level. The in vivo anticaries efficacy of ASA has further been proved using the rat caries model. In conclusion, ASA as an acetylation agent attenuated the cariogenic virulence of S. mutans, suggesting the potential value of protein acetylation on antimicrobial and anti-biofilm applications to S. mutans.}, } @article {pmid38222503, year = {2024}, author = {Steyn, HJF and White, LJ and Hilton, KLF and Hiscock, JR and Pohl, CH}, title = {Supramolecular Self-Associating Amphiphiles Inhibit Biofilm Formation by the Critical Pathogens, Pseudomonas aeruginosa and Candida albicans.}, journal = {ACS omega}, volume = {9}, number = {1}, pages = {1770-1785}, pmid = {38222503}, issn = {2470-1343}, abstract = {In 2019, 4.95 million deaths were directly attributed to antimicrobial-resistant bacterial infections globally. In addition, the mortality associated with fungal infections is estimated at 1.7 million annually, with many of these deaths attributed to species that are no longer susceptible to traditional therapeutic regimes. Herein, we demonstrate the use of a novel class of supramolecular self-associating amphiphilic (SSA) salts as antimicrobial agents against the critical pathogens Pseudomonas aeruginosa and Candida albicans. We also identify preliminary structure-activity relationships for this class of compound that will aid the development of next-generation SSAs demonstrating enhanced antibiofilm activity. To gain insight into the possible mode of action for these agents, a series of microscopy studies were performed, taking advantage of the intrinsic fluorescent nature of benzothiazole-substituted SSAs. Analysis of these data showed that the SSAs interact with the cell surface and that a benzothiazole-containing SSA inhibits hyphal formation by C. albicans.}, } @article {pmid38220430, year = {2024}, author = {Francis, D and Veeramanickathadathil Hari, G and Koonthanmala Subash, A and Bhairaddy, A and Joy, A}, title = {The biofilm proteome of Staphylococcus aureus and its implications for therapeutic interventions to biofilm-associated infections.}, journal = {Advances in protein chemistry and structural biology}, volume = {138}, number = {}, pages = {327-400}, doi = {10.1016/bs.apcsb.2023.08.002}, pmid = {38220430}, issn = {1876-1631}, mesh = {Humans ; *Staphylococcus aureus ; Proteome ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Staphylococcal Infections/drug therapy ; }, abstract = {Staphylococcus aureus is a major healthcare concern due to its ability to inflict life-threatening infections and evolve antibiotic resistance at an alarming pace. It is frequently associated with hospital-acquired infections, especially device-associated infections. Systemic infections due to S. aureus are difficult to treat and are associated with significant mortality and morbidity. The situation is worsened by the ability of S. aureus to form social associations called biofilms. Biofilms embed a community of cells with the ability to communicate with each other and share resources within a polysaccharide or protein matrix. S. aureus establish biofilms on tissues and conditioned abiotic surfaces. Biofilms are hyper-tolerant to antibiotics and help evade host immune responses. Biofilms exacerbate the severity and recalcitrance of device-associated infections. The development of a biofilm involves various biomolecules, such as polysaccharides, proteins and nucleic acids, contributing to different structural and functional roles. Interconnected signaling pathways and regulatory molecules modulate the expression of these molecules. A comprehensive understanding of the molecular biology of biofilm development would help to devise effective anti-biofilm therapeutics. Although bactericidal agents, antimicrobial peptides, bacteriophages and nano-conjugated anti-biofilm agents have been employed with varying levels of success, there is still a requirement for effective and clinically viable anti-biofilm therapeutics. Proteins that are expressed and utilized during biofilm formation, constituting the biofilm proteome, are a particularly attractive target for anti-biofilm strategies. The proteome can be explored to identify potential anti-biofilm drug targets and utilized for rational drug discovery. With the aim of uncovering the biofilm proteome, this chapter explores the mechanism of biofilm formation and its regulation. Furthermore, it explores the antibiofilm therapeutics targeted against the biofilm proteome.}, } @article {pmid38219940, year = {2024}, author = {Gao, Y and Wu, J and Shen, J and Xu, Y and Li, L and Wang, W and Zhou, N and Zhang, M}, title = {Chitosan modified magnetic nanocomposite for biofilm destruction and precise photothermal/photodynamic therapy.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {129402}, doi = {10.1016/j.ijbiomac.2024.129402}, pmid = {38219940}, issn = {1879-0003}, abstract = {Getting rid of the biofilms is a major challenge when treating skin and soft tissue infections (SSTI), an inflammatory illness brought on by bacteria. Traditional magnetic materials have a limited dispersibility and a biofilm permeable property, making it challenging to remove biofilms and causing infection to linger. To solve these problems, we developed a kind of magnetic composite nanoplatform coated with indocyanine green carbon dots and modified with chitosan modification (Fe-ICGCDs@CS). Fe-ICGCDs@CS has high dispersibility and improves the conductivity of biofilms under magnetic action. Fe-ICGCDs@CS can adsorb bacteria via the positive charge and achieve precise photothermal sterilization and photodynamic therapy (PDT). Moreover, by catalyzing hydrogen peroxide (2 mM), Fe-ICGCDs@CS can produce oxygen to relieve the anoxic state in the deep layer of biofilms and activate dormant bacteria to make them sensitive to external stimuli. All in all, unlike the common "just kill" sterilization model, Fe-ICGCDs@CS can accurately kill bacteria and be recovered by an external magnetic field at the end of treatment, thus reducing the potential biological toxicity of nanomaterials. Therefore, the proposed Fe-ICGCDs@CS provides a new antibacterial method with low biotoxicity for clinical application in the treatment of biofilm infections.}, } @article {pmid38219925, year = {2024}, author = {Zheng, X and Xie, J and Chen, W and Liu, M and Xie, L}, title = {Boosting anaerobic digestion of long chain fatty acid with microbial electrolysis cell combining metal organic framework as cathode: Biofilm construction and metabolic pathways.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130284}, doi = {10.1016/j.biortech.2023.130284}, pmid = {38219925}, issn = {1873-2976}, abstract = {The role of metal organic framework (MOF) modified cathode in promoting long chain fatty acid (LCFA) methanation was identified in microbial electrolysis cell coupled anaerobic digestion (MEC-AD) system. The maximum methane production rate of MEC-AD-MOF achieved 49.8 ± 3.4 mL/d, which increased by 41 % compared to MEC-AD-C. The analysis of bio-cathode biofilm revealed that microbial activity, distribution, population, and protein secretion prompted by MOF cathode, which in turn led to an acceleration of electron transfer between the cathode and microbes. Specifically, the relative abundance of acetate-oxidizing bacterium (Mesotoga) in MEC-AD-MOF was 1.5-3.6 times higher than that in MEC-AD-C, with a co-metabolized enrichment of Methanobacterium. Moreover, MOF cathode reinforced LCFA methanation by raising the relative abundance of genes coded key enzymes involved in CO2-reducing pathway, and elevating the tolerance of microbes to LCFA inhibition. These results indicate that MOF can enhance biofilm construction in MEC-AD, thereby improving the treatment performance of lipid wastewater.}, } @article {pmid38219918, year = {2024}, author = {Upadhyay, A and Pal, D and Kumar, A}, title = {Interrogating Salmonella Typhi biofilm formation and dynamics to understand antimicrobial resistance.}, journal = {Life sciences}, volume = {}, number = {}, pages = {122418}, doi = {10.1016/j.lfs.2024.122418}, pmid = {38219918}, issn = {1879-0631}, abstract = {AIMS: Salmonella Typhi biofilm-mediated infections are globally rising. Due to the emergence of drug resistance antibiotics did not show effective results against S. Typhi biofilm. Therefore, there is an urgent need for an in-depth interrogation of S. Typhi biofilm to understand its formation kinetics, compositions, and surface charge value.

METHODS: This study utilized the S. Typhi MTCC-733 strain from a microbial-type culture collection in India. The S. Typhi biofilm was formed on a glass slide in a biofilm development apparatus. Typhoidal biofilm analysis was done with the help of various assays such as a crystal violet assay, SEM analysis, FTIR analysis, Raman analysis, and zeta potential analysis.

KEY FINDING: This article contained a comprehensive assessment of the typhoid biofilm formation kinetics, biofilm compositions, and surface charge which revealed that cellulose was a major molecule in the typhoidal biofilm which can be used as a major biofilm drug target against typhoidal biofilm.

SIGNIFICANCE: This study provided interrogations about typhoidal biofilm kinetics which provided ideas about the biofilm composition. The cellulose molecule showed a major component of S. Typhi biofilm and it could potentially involved in drug resistance, and offer a promising avenue for developing a new antibiofilm therapeutic target to conquer the big obstacle of drug resistance. The obtained information can be instrumental in designing novel therapeutic molecules in the future to combat typhoidal biofilm conditions effectively for overcoming antibiotic resistance against bacterial infection Salmonella.}, } @article {pmid38219343, year = {2024}, author = {Tian, L and Gao, C and Lu, J and Liao, S and Gong, G}, title = {Key biological processes and essential genes for Proteus mirabilis biofilm development inhibition by protocatechuic acid.}, journal = {International journal of food microbiology}, volume = {412}, number = {}, pages = {110570}, doi = {10.1016/j.ijfoodmicro.2024.110570}, pmid = {38219343}, issn = {1879-3460}, abstract = {Proteus mirabilis is an opportunistic pathogen linked to human urinary tract infections, and is potentially present as a foodborne pathogen within poultry products, including broiler chickens. This report outlines the inhibitory impacts of protocatechuic acid (PCA) on P. mirabilis isolated from a broiler slaughterhouse in China as well as its biofilm. This investigation encompasses assays related to motility and adhesion, bacterial metabolic activity, extracellular polymer (EPS) production, and scavenging capacity. The findings demonstrated that PCA reduced biofilm formation by 61 %. Transcriptomics findings identified that PCA limited the expression of genes like PstS that promote adhesin formation, rbsA and RcsB that alter bacterial chemotaxis, lipopolysaccharide synthesis genes LpxA and EptB, and cell wall synthesis genes MurF and MrdA, and affects the Regulator of Capsule Synthesis (RCS) two-component modulation system. Weighted gene co-expression network analysis (WGCNA) was conducted to identify the core genes. Furthermore, the binding sites of PCA to cytochrome oxidases cydA and cydB, two subunits of ATP synthase atpI and atpH, and ftsZ, which regulate bacterial division, were predicted via molecular docking. Metabolome analysis determined that PCA critically influenced coenzyme A biosynthesis, nucleotide metabolism, alanine, aspartic acid, and glutamate metabolic pathways of P. mirabilis. Therefore, PCA impacts metabolism within bacteria via various pathways, limiting the levels of extracellular polymer and bacterial viability to hinder biofilm formation. Additionally, we prepared an antibacterial plastic film containing protocatechuic acid using PVA as the monomer and CNC as the reinforcing agent. We examined the mechanical and antibacterial properties of this film. When used to wrap chicken, it reduced the total number of colonies, slowed the deterioration of chicken, and maintained the freshness of chicken. In conclusion, the information outlined in this study complements our comprehension of P. mirabilis inhibition by PCA and provides clues for the reduction of foodborne infections associated with P. mirabilis.}, } @article {pmid38218138, year = {2024}, author = {Schuelke-Sanchez, A and Yennawar, NH and Weinert, EE}, title = {Oxygen-selective regulation of cyclic di-GMP synthesis by a globin coupled sensor with a shortened linking domain modulates Shewanella sp. ANA-3 biofilm.}, journal = {Journal of inorganic biochemistry}, volume = {252}, number = {}, pages = {112482}, doi = {10.1016/j.jinorgbio.2024.112482}, pmid = {38218138}, issn = {1873-3344}, abstract = {Bacteria utilize heme proteins, such as globin coupled sensors (GCSs), to sense and respond to oxygen levels. GCSs are predicted in almost 2000 bacterial species and consist of a globin domain linked by a central domain to a variety of output domains, including diguanylate cyclase domains that synthesize c-di-GMP, a major regulator of biofilm formation. To investigate the effects of middle domain length and heme edge residues on GCS diguanylate cyclase activity and cellular function, a putative diguanylate cyclase-containing GCS from Shewanella sp. ANA-3 (SA3GCS) was characterized. Binding of O2 to the heme resulted in activation of diguanylate cyclase activity, while NO and CO binding had minimal effects on catalysis, demonstrating that SA3GCS exhibits greater ligand selectivity for cyclase activation than many other diguanylate cyclase-containing GCSs. Small angle X-ray scattering analysis of dimeric SA3GCS identified movement of the cyclase domains away from each other, while maintaining the globin dimer interface, as a potential mechanism for regulating cyclase activity. Comparison of the Shewanella ANA-3 wild type and SA3GCS deletion (ΔSA3GCS) strains identified changes in biofilm formation, demonstrating that SA3GCS diguanylate cyclase activity modulates Shewanella phenotypes.}, } @article {pmid38218075, year = {2024}, author = {Yuan, CY and Yan, WJ and Sun, FY and Tu, HH and Lu, JJ and Feng, L and Dong, WY}, title = {Management of biofilm by an innovative layer-structured membrane for membrane biofilm reactor (MBfR) to efficient methane oxidation coupled to denitrification (AME-D).}, journal = {Water research}, volume = {251}, number = {}, pages = {121107}, doi = {10.1016/j.watres.2024.121107}, pmid = {38218075}, issn = {1879-2448}, abstract = {Aerobic methane oxidation coupled with denitrification (AME-D) has garnered significant attention as a promising technology for nitrogen removal from water. Effective biofilm management on the membrane surface is essential to enhance the efficiency of nitrate removal in AME-D systems. In this study, we introduce a novel and scalable layer-structured membrane (LSM) developed using a meticulously designed polyurethane sponge. The application of the LSM in advanced biofilm management for AME-D resulted in a substantial enhancement of denitrification performance. Our experimental results demonstrated remarkable improvements in nitrate-removal flux (92.8 mmol-N m[-2] d[-1]) and methane-oxidation rate (325.6 mmol m[-2] d[-1]) when using an LSM in a membrane biofilm reactor (L-MBfR) compared with a conventional membrane reactor (C-MBfR). The l-MBfR exhibited 12.4-, 6.8- and 3.4-fold increases in nitrate-removal rate, biomass-retention capacity, and methane-oxidation rate, respectively, relative to the control C-MBfR. Notably, the l-MBfR demonstrated a 3.5-fold higher abundance of denitrifying bacteria, including Xanthomonadaceae, Rhodocyclaceae, and Methylophilaceae. In addition, the denitrification-related enzyme activity was twice as high in the l-MBfR than in the C-MBfR. These findings underscore the LSM's ability to create anoxic/anaerobic microenvironments conducive to biofilm formation and denitrification. Furthermore, the LSM exhibited a unique advantage in shaping microbial community structures and facilitating cross-feeding interactions between denitrifying bacteria and aerobic methanotrophs. The results of this study hold great promise for advancing the application of MBfRs in achieving efficient and reliable nitrate removal through the AME-D pathway, facilitated by effective biofilm management.}, } @article {pmid38217950, year = {2024}, author = {Gunathilaka, GADKK and Dewasmika, WAPM and Sandaruwan, UM and Neelawala, NGDAK and Madhumali, GED and Dissanayake, BN and Priyantha, MAR and Prasada, DVP and Dissanayake, DRA}, title = {Biofilm-forming ability, antibiotic resistance and phylogeny of Escherichia coli isolated from extra intestinal infections of humans, dogs, and chickens.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {105}, number = {}, pages = {102123}, doi = {10.1016/j.cimid.2023.102123}, pmid = {38217950}, issn = {1878-1667}, abstract = {Escherichia coli (E. coli) causes various infections in humans and animals. The biofilm-forming ability of E. coli has increased antimicrobial resistance and capacity to cause recurrent and chronic infections. This study determined the biofilm-forming ability of E. coli isolated from extraintestinal infections of humans, chickens, and dogs in relation to the phylogroup, type of infection, and antibiotic resistance. Isolates from chickens showed significantly higher biofilm-forming ability compared to those causing urinary tract infections in humans (p = 0.0001). Further, isolates belonging to phylogroup B1 displayed a higher likelihood to form biofilms. Resistance to ciprofloxacin and trimethoprim-sulfamethoxazole was positively correlated with biofilm-forming ability. Harbouring plasmid-mediated quinolone resistance gene, qnrS was also positively correlated with biofilm formation. This study provides insight into factors such as phylogroup and the type of infections that could enhance biofilm formation, as well as genotypic and phenotypic antibiotic resistance that could correlate with the ability to form biofilms.}, } @article {pmid38214582, year = {2024}, author = {Datta, S and Nag, S and Roy, DN}, title = {Biofilm-producing antibiotic-resistant bacteria in Indian patients: a comprehensive review.}, journal = {Current medical research and opinion}, volume = {}, number = {}, pages = {1-32}, doi = {10.1080/03007995.2024.2305241}, pmid = {38214582}, issn = {1473-4877}, abstract = {For the past few years, microbial biofilms have been emerging as a significant threat to the modern healthcare system, and their prevalence and antibiotic resistance threat gradually increase daily among the human population. The biofilm has a remarkable impact in the field of infectious diseases, in particular healthcare-associated infections related to indwelling devices such as catheters, implants, artificial heart valves, and prosthetic joints. Bacterial biofilm potentially adheres to any biotic or abiotic surfaces that give specific shelter to the microbial community, making them less susceptible to many antimicrobial agents and even resistant to the immune cells of animal hosts. Around thirty clinical research reports available in PUBMED have been considered to establish the occurrence of biofilm-forming bacteria showing resistance against several regular antibiotics prescribed against infection by clinicians among Indian patients. After the extensive literature review, our observation exhibits a high predominance of biofilm formation among bacteria such as Escherichia sp., Streptococcus sp., Staphylococcus sp., and Pseudomonas sp., those are the most common biofilm-producing antibiotic-resistant bacteria among Indian patients with urinary tract infections and/or catheter-related infections, respiratory tract infections, dental infections, skin infections, and implant-associated infections. This review demonstrates that biofilm-associated bacterial infections constantly elevate in several pathological conditions along with the enhancement of the multi-drug resistance phenomenon.}, } @article {pmid38214428, year = {2024}, author = {Cox, CA and Manavathu, EK and Wakade, S and Myntti, M and Vazquez, JA}, title = {Efficacy of biofilm disrupters against Candida auris and other Candida species in monomicrobial and polymicrobial biofilms.}, journal = {Mycoses}, volume = {67}, number = {1}, pages = {e13684}, doi = {10.1111/myc.13684}, pmid = {38214428}, issn = {1439-0507}, support = {//Next Science/ ; }, abstract = {Candida species are now considered global threats by the CDC and WHO. Candida auris specifically is on the critical pathogen threat list along with Candida albicans. In addition, it is not uncommon to find Candida spp. in a mixed culture with bacterial organisms, especially Staphylococcus aureus producing polymicrobial infections. To eradicate these organisms from the environment and from patient surfaces, surface agents such as chlorhexidine (CHD) and Puracyn are used. Biofilm disrupters (BDs) are novel agents with a broad spectrum of antimicrobial activity and have been used in the management of chronic wounds and to sterilise environmental surfaces for the past several years. The goal of this study was to evaluate BDs (BlastX, Torrent, NSSD) and CHD against Candida spp. and S. aureus using zone of inhibition assays, biofilm and time-kill assays. All BDs and CHD inhibited C. auris growth effectively in a concentration-dependent manner. Additionally, CHD and the BDs showed excellent antimicrobial activity within polymicrobial biofilms. A comparative analysis of the BDs and CHD against C. auris and C. albicans using biofilm kill-curves showed at least 99.999% killing. All three BDs and CHD have excellent activity against different Candida species, including C. auris. However, one isolate of C. auris in a polymicrobial biofilm assay showed resistance/tolerance to CHD, but not to the BDs. The fungicidal activity of these novel agents will be valuable in eradicating surface colonisation of Candida spp, especially C. auris from colonised environmental surfaces and from wounds in colonised patients.}, } @article {pmid38214427, year = {2024}, author = {Gao, Y and Shen, J and Yinzhang, H and Yang, L}, title = {Performance and microbial response to nitrate nitrogen removal from simulated groundwater by electrode biofilm reactor with Ti/CNT/Cu5-Pd5 catalytic cathode.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {96}, number = {1}, pages = {e10974}, doi = {10.1002/wer.10974}, pmid = {38214427}, issn = {1554-7531}, support = {51908277//National Natural Science Foundation of China/ ; BK20190320//Jiangsu Provincial Natural Science Foundation/ ; YF202103//Science and Technology Project of Jiangsu Fang Tian Power Technology Co., Ltd./ ; }, abstract = {To enhance the removal of nitrate nitrogen (NO3 [-] -N) in groundwater with a low C/N ratio, electrocatalytic reduction of NO3 [-] -N has received extensive attention since its electrons can be directly produced in situ while simultaneously providing a clean electronic donor of hydrogen for denitrifying bacteria. In this study, Ti/CNT/Cu(?)Pd bimetallic catalytic electrodes with different copper-palladium (Cu(?)Pd) ratios were prepared by electrodeposition onto carbon nanotube (CNT) using titanium (Ti) plates. The results showed that the NO3 [-] -N conversion rate by Ti/CNT/Cu5-Pd5 electrode was the highest (53.60%) compared with other Cu(?)Pd electrode ratios because of the combined role of the copper's high NO3 [-] -N catalytic activity and the palladium's high N2 selectivity. A new type of electrode biofilm reactor (EBR) with Ti/CNT/Cu5-Pd5 cathode, biochar substrate was constructed to explore the removal ability of NO3 [-] -N in simulated low C/N groundwater. When the influent NO3 [-] -N concentration was 30 mg/L, under the condition of a 30 mA electronic current and hydraulic retention time (HRT) of 12 h, the removal rate of NO3 [-] -N could reach as high as 78.1 ± 1.2%, and the N2 conversion rate was 99.7%. The horizontal distribution of microbial communities in EBR showed that the denitrification capacity was significantly improved through the electrochemical catalytic reduction of the Ti/CNT/Cu5-Pd5 cathode and the supply of the hydrogen electron donor to autotrophic denitrogenerating microbes such as Anaerobacillus, Thauera, and Hydrophaga. This study provides a new bimetallic catalytic cathode to enhance the removal of NO3 [-] -N in groundwater with a low C/N ratio. PRACTITIONER POINTS: The Cu5Pd5/CNTs/Ti electrode is beneficial to the adsorption and reduction of NO3 [-] -N to N2 . The production of hydrogen electron donors by cathode promoted nitrogen degradation. Activated electrodes together with denitrifying microorganisms contributed to the improved N removal rate.}, } @article {pmid38213393, year = {2024}, author = {Halary, S and Duval, C and Marie, B and Bernard, C and Piquet, B and Gros, O and Bourguet-Kondracki, ML and Duperron, S}, title = {Genomes of nine biofilm-forming filamentous strains of Cyanobacteria (genera Jaaginema, Scytonema, and Karukerafilum gen. nov.) isolated from mangrove habitats of Guadeloupe (Lesser Antilles).}, journal = {FEMS microbes}, volume = {5}, number = {}, pages = {xtad024}, pmid = {38213393}, issn = {2633-6685}, abstract = {Biofilm-forming cyanobacteria are abundant in mangrove ecosystems, colonizing various niches including sediment surface and periphyton where they can cover large areas, yet have received limited attention. Several filamentous isolates were recently isolated from Guadeloupe, illustrating the diversity and novelty present in these biofilms. In this study, nine strains belonging to three novel lineages found abundantly in Guadeloupe biofilms are characterized by genome sequencing, morphological and ultrastructural examination, metabolome fingerprinting and searched for secondary metabolites biosynthesis pathways. Assignation of two lineages to known genera is confirmed, namely Scytonema and Jaaginema. The third lineage corresponds to a new Coleofasciculales genus herein described as Karukerafilum gen. nov. The four strains belonging to this genus group into two subclades, one of which displays genes necessary for nitrogen fixation as well as the complete pathway for geosmin production. This study gives new insights into the diversity of mangrove biofilm-forming cyanobacteria, including genome-based description of a new genus and the first genome sequence available for the genus Jaaginema.}, } @article {pmid38212356, year = {2024}, author = {Gao, Y and Bernard, O and Fanesi, A and Perré, P and Lopes, F}, title = {The effect of light intensity on microalgae biofilm structures and physiology under continuous illumination.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {1151}, pmid = {38212356}, issn = {2045-2322}, support = {201806120042//Chinese Government Scholarship/ ; PhotoBiofilm Explorer/LaSIPS Greenbelt, ANR-20-CE43-0008//Agence Nationale de la Recherche/ ; PhotoBiofilm Explorer/LaSIPS Greenbelt, ANR-20-CE43-0008//Agence Nationale de la Recherche/ ; }, abstract = {The interest by biofilm-based microalgae technologies has increased lately due to productivity improvement, energy consumption reduction and easy harvesting. However, the effect of light, one key factor for system's operation, received less attention than for planktonic cultures. This work assessed the impact of Photon Flux Density (PFD) on Chlorella vulgaris biofilm dynamics (structure, physiology, activity). Microalgae biofilms were cultivated in a flow-cell system with PFD from 100 to 500 [Formula: see text]. In the first stage of biofilm development, uniform cell distribution was observed on the substratum exposed to 100 [Formula: see text] while cell clusters were formed under 500 [Formula: see text]. Though similar specific growth rate in exponential phase (ca. 0.3 [Formula: see text]) was obtained under all light intensities, biofilm cells at 500 [Formula: see text] seem to be ultimately photoinhibited (lower final cell density). Data confirm that Chlorella vulgaris showed a remarkable capability to cope with high light. This was marked for sessile cells at 300 [Formula: see text], which reduce very rapidly (in 2 days) their chlorophyll-a content, most probably to reduce photodamage, while maintaining a high final cell density. Besides cellular physiological adjustments, our data demonstrate that cellular spatial organization is light-dependent.}, } @article {pmid38212273, year = {2024}, author = {Zhao, Y and Liu, Y and Liao, R and Ran, P and Liu, Y and Li, Z and Shao, J and Zhao, L}, title = {Biofilm Microenvironment-Sensitive Piezoelectric Nanomotors for Enhanced Penetration and ROS/NO Synergistic Bacterial Elimination.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c15689}, pmid = {38212273}, issn = {1944-8252}, abstract = {Sonodynamic therapy offers a highly accurate treatment for bacterial infections; however, its antibacterial efficacy is hindered by bacterial biofilms that limit the penetration of sonosensitizers. Herein, a nitric oxide (NO)-driven mushroom-like Janus nanomotor (BT@PDA-La) based on the unilateral coating of polydopamine (PDA) on piezoelectric tetragonal barium titanate (BT) and further modified with l-arginine (l-Arg) on the PDA side is fabricated. In the infected microenvironment with high levels of H2O2, NO is produced unilaterally from BT@PDA-La, thus leading to its self-propelled movement and facilitating its permeability in the biofilm. Under ultrasonic vibrations, the piezoelectric effect of BT@PDA-La is triggered by the exogenous mechanical wave, and toxic reactive oxygen species (ROS) are efficiently generated via an in situ catalytic reaction. The synergistic treatment with ROS/NO achieved the destruction of biofilms and embedded drug-resistant bacteria in vitro. Importantly, BT@PDA-La exhibits excellent biofilm penetration capacity, effectively eliminating biofilm infection while accelerating the healing of infected muscles by alleviating oxidative stress, regulating inflammatory factors, and accelerating angiogenesis. Collectively, this study provides a promising strategy for enhancing the penetration of pathological environment-driven nanomaterials through biofilms and advances the application of nanomotors for the therapy of bacterial infections in clinical medicine.}, } @article {pmid38212261, year = {2024}, author = {Luo, W and Zhang, M and Zhou, X and Xu, X and Cheng, X}, title = {Polyketides/nonribosomal peptides from Streptococcus mutans and their ecological roles in dental biofilm.}, journal = {Molecular oral microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/omi.12451}, pmid = {38212261}, issn = {2041-1014}, support = {82101002//National Natural Science Foundation of China/ ; 2022NSFSC1359,2022-901//Project of Science and Technology Department of Sichuan Province/ ; RCDWJS2021-16//Research Funding from West China Hospital of Stomatology Sichuan University/ ; }, abstract = {Streptococcus mutans is the major etiological agent of dental caries in humans. S. mutans overgrowth within dental biofilms can trigger biofilm dysbiosis, ultimately leading to the initiation or progression of dental caries. Polyketides and nonribosomal peptides (PKs/NRPs) are secondary metabolites with complex structures encoded by a cluster of biosynthetic genes. Although not essential for microbial growth, PKs/NRPs play important roles in physiological regulation. Three main classes of hybrid PKs/NRPs in S. mutans have been identified, including mutanobactin, mutanocyclin, and mutanofactin, encoded by the mub, muc, and muf gene clusters, respectively. These three hybrid PKs/NRPs play important roles in environmental adaptation, biofilm formation, and interspecies competition of S. mutans. In this review, we provide an overview of the major hybrid PKs/NRPs of S. mutans, including mutanobactin, mutanocyclin, and mutanofactin and address their ecological roles in dental biofilms. We place specific emphasis on important questions that are yet to be answered to provide novel insights into the cariogenic mechanism of S. mutans and facilitate improved management of dental caries. We highlight that S. mutans PKs/NRPs may be potential novel targets for the prevention and treatment of S. mutans-induced dental caries. The development of genomics, metabolomics, and mass spectrometry, together with the integration of various databases and bioinformatics tools, will allow the identification and synthesis of other secondary metabolites. Elucidating their physicochemical properties and their ecological roles in oral biofilms is crucial in the identification of novel targets for the ecological management of dental caries.}, } @article {pmid38211834, year = {2024}, author = {Sardi, JCO and Derissi Braz Carlton, J and Marcos, CM and Fusco Almeida, AM and Mendes Giannini, MJS}, title = {Unveiling the functional significance of the 14.3.3 protein: A key player in Paracoccidioides brasiliensis biofilm formation.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106537}, doi = {10.1016/j.micpath.2024.106537}, pmid = {38211834}, issn = {1096-1208}, abstract = {Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides spp. The interaction mediated by the presence of adhesins on the fungal surface and receptors in the extracellular matrix of the host, as well as the biofilm formation, is essential in its pathogenesis. Adhesins such as gp43, enolase, GAPDH (glyceraldehyde-3-phosphate dehydrogenase), and 14-3-3 have been demonstrated in the Paracoccidioides brasiliensis (Pb18) strain and recognized as necessary in the fungus-host interaction. The Pb 18 strain silenced to 14-3-3 showed changes in morphology, virulence, and adhesion capacity. The study aimed to evaluate the role of adhesin 14-3-3 in P. brasiliensis biofilm formation and the differential expression of genes related to adhesins, comparing planktonic and biofilm forms. The presence of biofilm was also verified in sutures in vitro and in vivo. The silenced strain (Pb14-3-3 aRNA) was compared with the wild type Pb18, determining the differential metabolic activity between the strains by the XTT reduction assay; the biomass by violet crystal and the polysaccharides by safranin, even as morphological differences by microscopic techniques. Differential gene expression for adhesins was also analyzed, comparing the relative expression of these in planktonic and biofilm forms at different times. The results suggested that the silencing of 14-3-3 protein altered the ability to form biofilm and its metabolism. The quantity of biomass was similar in both strains; however, the formation of exopolymeric substances and polysaccharide material was lower in the silenced strain. Our results showed increased expression of enolase, GAPDH, and 14-3-3 genes in the first periods of biofilm formation in the Pb18 strain. In contrast, the silenced strain showed a lower expression of these genes, indicating that gene silencing can influence the expression of other genes and be involved in the biofilm formation of P. brasiliensis. In vitro and in vivo assays using sutures confirmed this yeast's ability to form biofilm and may be implicated in the pathogenesis of paracoccidioidomycosis.}, } @article {pmid38207171, year = {2024}, author = {Kang, X and Yang, X and Bu, F and Feng, W and Liu, F and Xie, W and Li, G and Wang, X}, title = {GSH/pH Cascade-Responsive Nanoparticles Eliminate Methicillin-Resistant Staphylococcus aureus Biofilm via Synergistic Photo-Chemo Therapy.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c17198}, pmid = {38207171}, issn = {1944-8252}, abstract = {Bacterial biofilm infection threatens public health, and efficient treatment strategies are urgently required. Phototherapy is a potential candidate, but it is limited because of the off-targeting property, vulnerable activity, and normal tissue damage. Herein, cascade-responsive nanoparticles (NPs) with a synergistic effect of phototherapy and chemotherapy are proposed for targeted elimination of biofilms. The NPs are fabricated by encapsulating IR780 in a polycarbonate-based polymer that contains disulfide bonds in the main chain and a Schiff-base bond connecting vancomycin (Van) pendants in the side chain (denoted as SP-Van@IR780 NPs). SP-Van@IR780 NPs specifically target bacterial biofilms in vitro and in vivo by the mediation of Van pendants. Subsequently, SP-Van@IR780 NPs are decomposed into small size and achieve deep biofilm penetration due to the cleavage of disulfide bonds in the presence of GSH. Thereafter, Van is then detached from the NPs because the Schiff base bonds are broken at low pH when SP@IR780 NPs penetrate into the interior of biofilm. The released Van and IR780 exhibit a robust synergistic effect of chemotherapy and phototherapy, strongly eliminate the biofilm both in vitro and in vivo. Therefore, these biocompatible SP-Van@IR780 NPs provide a new outlook for the therapy of bacterial biofilm infection.}, } @article {pmid38206896, year = {2024}, author = {Aragão, MGB and Tedesco, AC and Borges, HS and Aires, CP and Corona, SAM}, title = {Chitosan nanoparticles loaded with epigallocatechin-3-gallate: synthesis, characterisation, and effects against Streptococcus mutans biofilmEpigallocatechin-loaded chitosan nanoparticles: effects against Streptococcus mutans biofilm.}, journal = {Natural product research}, volume = {}, number = {}, pages = {1-8}, doi = {10.1080/14786419.2024.2302321}, pmid = {38206896}, issn = {1478-6427}, abstract = {This study evaluated the effects of chitosan nanoparticles loaded with epigallocatechin-3-gallate (EGCG) against Streptococcus mutans biofilm. EGCG-loaded chitosan (Nchi + EGCG) nanoparticles and Chitosan (Nchi) nanoparticles were prepared by ion gelation process and characterised regarding particle size, polydispersion index, zeta potential, and accelerated stability. S mutans biofilms were treated twice daily with NaCl 0.9% (negative control), Nchi, Nchi + EGCG, and chlorhexidine (CHX) 0.12% (positive control). After 67 h, the biofilms were evaluated for acidogenesis, bacterial viability and dry weight. Biofilm morphology and structure were analysed by scanning electron microscopy. The nanoformulations presented medium to short-term stability, size of 500 nm, and polydispersion index around 0.400. Treatments affected cell morphology and biofilm structure. However, no effects on microbial viability, biofilm dry weight, and acidogenesis were observed. Thus, the nanoformulations disassembled the biofilm matrix without affecting microbial viability, which makes them promising candidates for the development of dental caries preventive and therapeutic agents.}, } @article {pmid38206049, year = {2024}, author = {Potapova, A and Garvey, W and Dahl, P and Guo, S and Chang, Y and Schwechheimer, C and Trebino, MA and Floyd, KA and Phinney, BS and Liu, J and Malvankar, NS and Yildiz, FH}, title = {Outer membrane vesicles and the outer membrane protein OmpU govern Vibrio cholerae biofilm matrix assembly.}, journal = {mBio}, volume = {}, number = {}, pages = {e0330423}, doi = {10.1128/mbio.03304-23}, pmid = {38206049}, issn = {2150-7511}, abstract = {Cholera remains a major public health concern. Vibrio cholerae, the causative agent of cholera, forms biofilms, which are critical for its transmission, infectivity, and environmental persistence. While we know that the V. cholerae biofilm matrix contains exopolysaccharide, matrix proteins, and extracellular DNA, we do not have a comprehensive understanding of the majority of biofilm matrix components. Here, we discover outer membrane vesicles (OMVs) within the biofilm matrix of V. cholerae. Proteomic analysis of the matrix and matrix-associated OMVs showed that OMVs carry key matrix proteins and Vibrio polysaccharide (VPS) to help build biofilms. We also characterize the role of the highly abundant outer membrane protein OmpU in biofilm formation and show that it impacts biofilm architecture in a VPS-dependent manner. Understanding V. cholerae biofilm formation is important for developing a better prevention and treatment strategy framework.}, } @article {pmid38206029, year = {2024}, author = {Pomerleau, M and Charron-Lamoureux, V and Léonard, L and Grenier, F and Rodrigue, S and Beauregard, PB}, title = {Adaptive laboratory evolution reveals regulators involved in repressing biofilm development as key players in Bacillus subtilis root colonization.}, journal = {mSystems}, volume = {}, number = {}, pages = {e0084323}, doi = {10.1128/msystems.00843-23}, pmid = {38206029}, issn = {2379-5077}, abstract = {In this study, we aimed to enhance the abilities of the plant-beneficial bacterium Bacillus subtilis to colonize plant roots in the presence of competing Pseudomonas bacteria. To achieve this, we conducted adaptive laboratory experiments, allowing Bacillus to evolve in a defined environment. We successfully obtained strains of Bacillus that were more effective at colonizing plant roots than the ancestor strain. To identify the genetic changes driving this improvement, we sequenced the genomes of these evolved strains. Interestingly, mutations that facilitated the formation of robust biofilms on roots were predominant. Many of these evolved Bacillus isolates also displayed the remarkable ability to outcompete Pseudomonas species. Our research sheds light on the mutational paths selected in Bacillus subtilis to thrive in root environments and offers exciting prospects for improving beneficial traits in plant growth-promoting microorganisms. Ultimately, this could pave the way for the development of more effective biofertilizers and sustainable agricultural practices.}, } @article {pmid38205963, year = {2024}, author = {Mushtaq, F and Nadeem, A and Yabrag, A and Bala, A and Karah, N and Zlatkov, N and Nyunt Wai, S and Uhlin, BE and Ahmad, I}, title = {Colony phase variation switch modulates antimicrobial tolerance and biofilm formation in Acinetobacter baumannii.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0295623}, doi = {10.1128/spectrum.02956-23}, pmid = {38205963}, issn = {2165-0497}, abstract = {As a WHO top-priority drug-resistant microbe, Acinetobacter baumannii significantly contributes to hospital-associated infections worldwide. One particularly intriguing aspect is its ability to reversibly switch its colony morphotype on agar plates, which has been remarkably underexplored. In this study, we employed various microscopic techniques and phenotypic assays to investigate the colony phase variation switch under different clinically and environmentally relevant conditions. Our findings reveal that the presence of a poly N-acetylglucosamine-positive extracellular matrix layer contributes to the protection of bacteria from the bactericidal effects of colistin. Furthermore, we provide intriguing insights into the multicellular lifestyle of A. baumannii, specifically in the context of colony switch variation within its predatory host, Acanthamoeba castellanii.}, } @article {pmid38205812, year = {2024}, author = {Le, KY and Otto, M}, title = {Approaches to combating methicillin-resistant staphylococcus aureus (MRSA) biofilm infections.}, journal = {Expert opinion on investigational drugs}, volume = {}, number = {}, pages = {}, doi = {10.1080/13543784.2024.2305136}, pmid = {38205812}, issn = {1744-7658}, } @article {pmid38205800, year = {2024}, author = {Xu, Y and Chen, B and Xu, L and Zhang, G and Cao, L and Liu, N and Wang, W and Qian, H and Shao, M}, title = {Urchin-like Fe3O4@Bi2S3 Nanospheres Enable the Destruction of Biofilm and Efficiently Antibacterial Activities.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c17888}, pmid = {38205800}, issn = {1944-8252}, abstract = {Biofilm-associated infections (BAIs) have been considered a major threat to public health, which induce persistent infections and serious complications. The poor penetration of antibacterial agents in biofilm significantly limits the efficiency of combating BAIs. Magnetic urchin-like core-shell nanospheres of Fe3O4@Bi2S3 were developed for physically destructing biofilm and inducing bacterial eradication via reactive oxygen species (ROS) generation and innate immunity regulation. The urchin-like magnetic nanospheres with sharp edges of Fe3O4@Bi2S3 exhibited propeller-like rotation to physically destroy biofilm under a rotating magnetic field (RMF). The mild magnetic hyperthermia improved the generation of ROS and enhanced bacterial eradication. Significantly, the urchin-like nanostructure and generated ROS could stimulate macrophage polarization toward the M1 phenotype, which could eradicate the persistent bacteria with a metabolic inactivity state through phagocytosis, thereby promoting the recovery of implant infection and inhibiting recurrence. Thus, the design of magnetic-driven sharp-shaped nanostructures of Fe3O4@Bi2S3 provided enormous potential in combating biofilm infections.}, } @article {pmid38205780, year = {2024}, author = {Rojas, D and Marcoleta, AE and Gálvez-Silva, M and Varas, MA and Díaz, M and Hernández, M and Vargas, C and Nourdin-Galindo, G and Koch, E and Saldivia, P and Vielma, J and Gan, YH and Chen, Y and Guiliani, N and Chávez, FP}, title = {Inorganic Polyphosphate Affects Biofilm Assembly, Capsule Formation, and Virulence of Hypervirulent ST23 Klebsiella pneumoniae.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00509}, pmid = {38205780}, issn = {2373-8227}, abstract = {The emergence of hypervirulent Klebsiella pneumoniae (hvKP) strains poses a significant threat to public health due to high mortality rates and propensity to cause severe community-acquired infections in healthy individuals. The ability to form biofilms and produce a protective capsule contributes to its enhanced virulence and is a significant challenge to effective antibiotic treatment. Polyphosphate kinase 1 (PPK1) is an enzyme responsible for inorganic polyphosphate synthesis and plays a vital role in regulating various physiological processes in bacteria. In this study, we investigated the impact of polyP metabolism on the biofilm and capsule formation and virulence traits in hvKP using Dictyostelium discoideum amoeba as a model host. We found that the PPK1 null mutant was impaired in biofilm and capsule formation and showed attenuated virulence in D. discoideum compared to the wild-type strain. We performed a proteomic analysis to gain further insights into the underlying molecular mechanism. The results revealed that the PPK1 mutant had a differential expression of proteins involved in capsule synthesis (Wzi-Ugd), biofilm formation (MrkC-D-H), synthesis of the colibactin genotoxin precursor (ClbB), as well as proteins associated with the synthesis and modification of lipid A (ArnB-LpxC-PagP). These proteomic findings corroborate the phenotypic observations and indicate that the PPK1 mutation is associated with impaired biofilm and capsule formation and attenuated virulence in hvKP. Overall, our study highlights the importance of polyP synthesis in regulating extracellular biomolecules and virulence in K. pneumoniae and provides insights into potential therapeutic targets for treating K. pneumoniae infections.}, } @article {pmid38204138, year = {2024}, author = {Viveiro, LRDG and Rehem, AR and De Souza Santos, EL and Carmo, PHFD and Campos Junqueira, J and Scorzoni, L}, title = {In vitro effects of selective serotonin reuptake inhibitors on Cryptococcus gattii Capsule and biofilm.}, journal = {Pathogens and disease}, volume = {}, number = {}, pages = {}, doi = {10.1093/femspd/ftae001}, pmid = {38204138}, issn = {2049-632X}, abstract = {Infections caused by Cryptococcus gattii mainly affect immunocompetent individuals and the treatment presents important limitations. This study aimed to validate the efficacy of Selective Serotonin Reuptake Inhibitors (SSRI) fluoxetine hydrochloride (FLH) and paroxetine hydrochloride (PAH) in vitro against C. gattii. The antifungal activity of SSRI using the microdilution method revealed a minimal inhibitory concentration (MIC) of 31.25 μg/mL. The combination of FLH or PAH with AmB were analyzed using the checkerboard assay and the synergistic effect of SSRI in combination with AmB were able to reduce the SSRI or AmB MIC values 4 to 8-fold. When examining the effect of SSRI on the induced capsules, we observed that FLH and PAH significantly decreased the size of C. gattii capsules. In addition, the effects of FLH and PAH were evaluated in biofilm biomass and viability. The SSRI were able to reduce biofilm biomass and biofilm viability. In conclusion, our results indicate the use of FLH and PAH exhibited in vitro anti-cryptococcal activity, representing a possible future alternative for the cryptococcosis treatment.}, } @article {pmid38203592, year = {2023}, author = {Guo, Q and Zhan, Y and Zhang, W and Wang, J and Yan, Y and Wang, W and Lin, M}, title = {Development and Regulation of the Extreme Biofilm Formation of Deinococcus radiodurans R1 under Extreme Environmental Conditions.}, journal = {International journal of molecular sciences}, volume = {25}, number = {1}, pages = {}, doi = {10.3390/ijms25010421}, pmid = {38203592}, issn = {1422-0067}, support = {2022YFA0912100//National Key Research and Development Programof China/ ; 31930004, 32150021, 32270067//National Natural Science Foundation of China/ ; CAAS-ZDRW202305, CAAS-ZDRW202303//Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences/ ; }, abstract = {To grow in various harsh environments, extremophiles have developed extraordinary strategies such as biofilm formation, which is an extremely complex and progressive process. However, the genetic elements and exact mechanisms underlying extreme biofilm formation remain enigmatic. Here, we characterized the biofilm-forming ability of Deinococcus radiodurans in vitro under extreme environmental conditions and found that extremely high concentrations of NaCl or sorbitol could induce biofilm formation. Meantime, the survival ability of biofilm cells was superior to that of planktonic cells in different extreme conditions, such as hydrogen peroxide stress, sorbitol stress, and high UV radiation. Transcriptome profiles of D. radiodurans in four different biofilm development stages further revealed that only 13 matched genes, which are involved in environmental information processing, carbohydrate metabolism, or stress responses, share sequence homology with genes related to the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Overall, 64% of the differentially expressed genes are functionally unknown, indicating the specificity of the regulatory network of D. radiodurans. The mutation of the drRRA gene encoding a response regulator strongly impaired biofilm formation ability, implying that DrRRA is an essential component of the biofilm formation of D. radiodurans. Furthermore, transcripts from both the wild type and the drRRA mutant were compared, showing that the expression of drBON1 (Deinococcus radioduransBON domain-containing protein 1) significantly decreased in the drRRA mutant during biofilm development. Further analysis revealed that the drBON1 mutant lacked the ability to form biofilm and DrRRA, and as a facilitator of biofilm formation, could directly stimulate the transcription of the biofilm-related gene drBON1. Overall, our work highlights a molecular mechanism mediated by the response regulator DrRRA for controlling extreme biofilm formation and thus provides guidance for future studies to investigate novel mechanisms that are used by D. radiodurans to adapt to extreme environments.}, } @article {pmid38203252, year = {2023}, author = {Romero-Montero, A and Melgoza-Ramírez, LJ and Ruíz-Aguirre, JA and Chávez-Santoscoy, A and Magaña, JJ and Cortés, H and Leyva-Gómez, G and Del Prado-Audelo, ML}, title = {Essential-Oils-Loaded Biopolymeric Nanoparticles as Strategies for Microbial and Biofilm Control: A Current Status.}, journal = {International journal of molecular sciences}, volume = {25}, number = {1}, pages = {}, doi = {10.3390/ijms25010082}, pmid = {38203252}, issn = {1422-0067}, support = {PAPIIT IN204722//DGAPA-UNAM/ ; CVU: 629447//CONAHCYT/ ; }, abstract = {The emergence of bacterial strains displaying resistance to the currently available antibiotics is a critical global concern. These resilient bacteria can form biofilms that play a pivotal role in the failure of bacterial infection treatments as antibiotics struggle to penetrate all biofilm regions. Consequently, eradicating bacteria residing within biofilms becomes considerably more challenging than their planktonic counterparts, leading to persistent and chronic infections. Among various approaches explored, essential oils loaded in nanoparticles based on biopolymers have emerged, promising strategies that enhance bioavailability and biological activities, minimize side effects, and control release through regulated pharmacokinetics. Different available reviews analyze nanosystems and essential oils; however, usually, their main goal is the analysis of their antimicrobial properties, and progress in biofilm combat is rarely discussed, or it is not the primary objective. This review aims to provide a global vision of biofilm conformation and describes mechanisms of action attributed to each EO. Furthermore, we present a comprehensive overview of the latest developments in biopolymeric nanoparticles research, especially in chitosan- and zein-based nanosystems, targeting multidrug-resistant bacteria in both their sessile and biofilm forms, which will help to design precise strategies for combating biofilms.}, } @article {pmid38202375, year = {2023}, author = {Rahmani Samani, M and D'Urso, G and Nazzaro, F and Fratianni, F and Masullo, M and Piacente, S}, title = {Phytochemical Investigation and Biofilm-Inhibitory Activity of Bachtiari Savory (Satureja bachtiarica Bunge) Aerial Parts.}, journal = {Plants (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, pmid = {38202375}, issn = {2223-7747}, abstract = {Satureja bachtiarica is an endemic plant from the Lamiaceae family, growing in the Zagros mountain range in Iran. Even if S. bachtiarica is reported to possess many biological activities, little is known about its chemical composition. For this reason, in the present research, a phytochemical investigation of this species was carried out. To have a preliminary metabolite profile of S. bachtiarica, the n-BuOH extract was analyzed using LC-ESI/LTQOrbitrap/MS/MS in negative ion mode, allowing the identification of specialized metabolites belonging to flavonoid, monoterpene, indol, phenylpropanoid, phenolic, lignan, coumarin, biphenyl, and triterpene classes. The LC-MS/MS analysis guided the isolation of compounds, and their structures were characterized using spectroscopic methods including 1D- and 2D-NMR experiments and HRMS[n] analysis. In this way, a compound never reported before belonging to the biphenyl class was identified. Total flavonoid content of the extract along with the antioxidant activity were assessed. Based on the traditional uses of S. bachtiarica suggesting potential antibacterial properties, an evaluation of the biofilm inhibitory activity of the extract and isolated compounds against mature biofilms of Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as their influence on the metabolism of sessile bacterial cells, was conducted. The results evidenced that some compounds including parmentin B, biphenyls, and 1-(1H-indole-3-carboxylate)-β-D-glucopyranoside might inhibit some changes occurring in the bacterial cells, which increases their virulence. In particular, biphenyl derivatives at a concentration of 80 μg/mL were capable of limiting remarkably the mature biofilms of A. baumannii and L. monocytogenes remarkably at a percentage ranging between 52.76% and 75.02%, and they reached an inhibition percentage of 69.28 % against E. coli. Biphenyl derivatives were also effective in exerting an inhibitory action against the mature biofilm of P. aeruginosa (inhibition ranging from 59.38% to 81.08%) and Staphylococcus aureus (inhibition percentage reached 82.94%). Of note, the biphenyl derivatives resulted in being capable of acting on the metabolism of the cells within the biofilm of all five pathogens.}, } @article {pmid38201695, year = {2023}, author = {Savitskaya, I and Zhantlessova, S and Kistaubayeva, A and Ignatova, L and Shokatayeva, D and Sinyavskiy, Y and Kushugulova, A and Digel, I}, title = {Prebiotic Cellulose-Pullulan Matrix as a "Vehicle" for Probiotic Biofilm Delivery to the Host Large Intestine.}, journal = {Polymers}, volume = {16}, number = {1}, pages = {}, pmid = {38201695}, issn = {2073-4360}, support = {AP09259491//the Ministry of Science and Higher Education of the Republic of Kazakhstan/ ; }, abstract = {This study describes the development of a new combined polysaccharide-matrix-based technology for the immobilization of Lactobacillus rhamnosus GG (LGG) bacteria in biofilm form. The new composition allows for delivering the bacteria to the digestive tract in a manner that improves their robustness compared with planktonic cells and released biofilm cells. Granules consisting of a polysaccharide matrix with probiotic biofilms (PMPB) with high cell density (>9 log CFU/g) were obtained by immobilization in the optimized nutrient medium. Successful probiotic loading was confirmed by fluorescence microscopy and scanning electron microscopy. The developed prebiotic polysaccharide matrix significantly enhanced LGG viability under acidic (pH 2.0) and bile salt (0.3%) stress conditions. Enzymatic extract of feces, mimicking colon fluid in terms of cellulase activity, was used to evaluate the intestinal release of probiotics. PMPB granules showed the ability to gradually release a large number of viable LGG cells in the model colon fluid. In vivo, the oral administration of PMPB granules in rats resulted in the successful release of probiotics in the colon environment. The biofilm-forming incubation method of immobilization on a complex polysaccharide matrix tested in this study has shown high efficacy and promising potential for the development of innovative biotechnologies.}, } @article {pmid38200708, year = {2024}, author = {Jiang, H and Wang, Z and Jia, AQ}, title = {Anti-Biofilm and Antivirulence Activities of 1,2,6-tri-O-galloyl-β-ᴅ-glucose against Proteus penneri.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxae004}, pmid = {38200708}, issn = {1365-2672}, abstract = {AIMS: The present study investigated the anti-virulence and anti-biofilm effects of 1,2,6-tri-O-galloyl-β-ᴅ-glucose (TGG), isolated from Camellia nitidissima Chi flowers, on Proteus penneri ALK 1200.

METHODS AND RESULTS: TGG was isolated from C. nitidissima Chi flowers using various chromatographic techniques. The milk plate assay, azocasein assay, and exopolysaccharides (EPS) inhibition assay revealed that TGG effectively inhibited the production of crucial virulence factors, including protease and EPS, in P. penneri ALK 1200. Furthermore, fourier transform infrared spectroscopic (FT-IR) analysis indicated that TGG interfered with the composition of P. penneri ALK 1200's cellular component, potentially reducing the bacteria's pathogenicity. In addition, crystal violet assay, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) analysis indicated a significant reduction in biofilm formation following TGG treatment. The swimming and swarming assays also showed that TGG reduced the motility of P. penneri ALK 1200. Furthermore, the qRT-PCR assay demonstrated that TGG down-regulated the expression of positive regulatory genes (hfq and flhD) responsible for motility and biofilm formation, while up-regulating the expression of the negative regulator of the quorum sensing system, bssS, in P. penneri ALK 1200.

CONCLUSIONS: TGG displayed potent anti-QS and anti-biofilm activity towards P. penneri ALK 1200.}, } @article {pmid38199359, year = {2024}, author = {Clark, GG and Geisler, D and Coey, EJ and Pollitz, LJ and Zaki, FR and Huang, C and Boppart, SA and Nguyen, TH}, title = {Influence of phosphate on bacterial release from activated carbon point-of-use filters and on biofilm characteristics.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {169932}, doi = {10.1016/j.scitotenv.2024.169932}, pmid = {38199359}, issn = {1879-1026}, abstract = {Point-of-use (POU) filters certified to remove lead are often composed of activated carbon and have been shown to release high concentrations of bacteria, including opportunistic pathogens. In this study, we examine the impacts of the common corrosion inhibitor phosphate on biofilm characteristics and the relationship between biofilm structure and bacterial release from POU filters. This knowledge is essential for understanding how best to use the filters and where these filters fit in a system where other lead contamination prevention measures may be in place. We measured the bacterial release from activated carbon POU filters fed with groundwater - a common source of drinking water - with and without phosphate. We used optical coherence tomography (OCT) to quantitatively characterize biofilm growing on activated carbon filter material in which the biofilms were fed groundwater with and without phosphate. Phosphate filters released significantly less (57-87 %) bacteria than groundwater filters, and phosphate biofilms (median thickness: 82-331 μm) grew to be significantly thicker than groundwater biofilms (median thickness: 122-221 μm). The phosphate biofilm roughness ranged from 97 to 142 % of the groundwater biofilm roughness and was significantly greater in most weeks. Phosphate biofilms also had fewer pores per biofilm volume and shorter channels connecting those pores.}, } @article {pmid38198973, year = {2024}, author = {Xia, Z and Ng, HY and Xu, D and Bae, S}, title = {Lumen air pressure regulated multifunctional microbiotas in membrane-aerated biofilm reactors for simultaneous nitrogen removal and antibiotic elimination from aquaculture wastewater.}, journal = {Water research}, volume = {251}, number = {}, pages = {121102}, doi = {10.1016/j.watres.2024.121102}, pmid = {38198973}, issn = {1879-2448}, abstract = {In this study, two membrane-aerated biofilm reactors (MABRs) were constructed: one solely utilizing biofilm and another hybrid MABR (HMABR) incorporating both suspended-sludge and biofilm to treat low C/N aquaculture wastewater under varying lumen air pressure (LAP). Both HMABR and MABR demonstrated superior nitrogen removal than conventional aeration reactors. Reducing LAP from 10 kPa to 2 kPa could enhance denitrification processes without severely compromising nitrification, resulting in an increase in total inorganic nitrogen (TIN) removal from 50.2±3.1 % to 71.6±1.0 %. The HMABR exhibited better denitrification efficacy than MABR, underscoring its potential for advanced nitrogen removal applications. A decline in LAP led to decreased extracellular polymeric substance (EPS) production, which could potentially augment reactor performance by minimizing mass transfer resistance while maintaining microbial matrix stability and function. Gene-centric metagenomics analysis revealed decreasing LAP impacted nitrogen metabolic potentials and electron flow pathways. The enrichment of napAB at higher LAP and the presence of complete ammonia oxidation (Comammox) Nitrospira at lower LAP indicated aerobic denitrification and Comammox processes in nitrogen removal. Multifunctional microbial communities developed under LAP regulation, diversifying the mechanisms for simultaneous nitrification-denitrification. Increased denitrifying gene pool (narGHI, nirK, norB) and enzymatic activity at a low LAP can amplify denitrification by promoting denitrifying genes and electron flow towards denitrifying enzymes. Sulfamethoxazole (SMX) was simultaneously removed with efficiency up to 80.2 ± 3.7 %, mainly via biodegradation, while antibiotic resistome and mobilome were propagated. Collectively, these findings could improve our understanding of nitrogen and antibiotic removal mechanisms under LAP regulation, offering valuable insights for the effective design and operation of MABR systems in aquaculture wastewater treatment.}, } @article {pmid38198810, year = {2024}, author = {Lin, J and Suo, J and Bao, B and Wei, H and Gao, T and Zhu, H and Zheng, X}, title = {Efficacy of EDTA-NS irrigation in eradicating Staphylococcus aureus biofilm-associated infection.}, journal = {Bone & joint research}, volume = {13}, number = {1}, pages = {40-51}, doi = {10.1302/2046-3758.131.BJR-2023-0141.R1}, pmid = {38198810}, issn = {2046-3758}, abstract = {AIMS: To investigate the efficacy of ethylenediaminetetraacetic acid-normal saline (EDTA-NS) in dispersing biofilms and reducing bacterial infections.

METHODS: EDTA-NS solutions were irrigated at different durations (1, 5, 10, and 30 minutes) and concentrations (1, 2, 5, 10, and 50 mM) to disrupt Staphylococcus aureus biofilms on Matrigel-coated glass and two materials widely used in orthopaedic implants (Ti-6Al-4V and highly cross-linked polyethylene (HXLPE)). To assess the efficacy of biofilm dispersion, crystal violet staining biofilm assay and colony counting after sonification and culturing were performed. The results were further confirmed and visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). We then investigated the efficacies of EDTA-NS irrigation in vivo in rat and pig models of biofilm-associated infection.

RESULTS: When 10 mM or higher EDTA-NS concentrations were used for ten minutes, over 99% of S. aureus biofilm formed on all three types of materials was eradicated in terms of absorbance measured at 595 nm and colony-forming units (CFUs) after culturing. Consistently, SEM and CSLM scanning demonstrated that less adherence of S. aureus could be observed on all three types of materials after 10 mM EDTA-NS irrigation for ten minutes. In the rat model, compared with NS irrigation combined with rifampin (Ti-6Al-4V wire-implanted rats: 60% bacteria survived; HXLPE particle-implanted rats: 63.3% bacteria survived), EDTA-NS irrigation combined with rifampin produced the highest removal rate (Ti-6Al-4V wire-implanted rats: 3.33% bacteria survived; HXLPE particle-implanted rats: 6.67% bacteria survived). In the pig model, compared with NS irrigation combined with rifampin (Ti-6Al-4V plates: 75% bacteria survived; HXLPE bearings: 87.5% bacteria survived), we observed a similar level of biofilm disruption on Ti-6Al-4V plates (25% bacteria survived) and HXLPE bearings (37.5% bacteria survived) after EDTA-NS irrigation combined with rifampin. The in vivo study revealed that the biomass of S. aureus biofilm was significantly reduced when treated with rifampin following irrigation and debridement, as indicated by both the biofilm bacterial burden and crystal violet staining. EDTA-NS irrigation (10 mM/10 min) combined with rifampin effectively removes S. aureus biofilm-associated infections both in vitro and in vivo.

CONCLUSION: EDTA-NS irrigation with or without antibiotics is effective in eradicating S. aureus biofilm-associated infection both ex and in vivo.}, } @article {pmid38198688, year = {2024}, author = {Le, KCM and Tran, ATQ and Vu, MP and Duong, PVQ and Nguyen, KT}, title = {Preventing Static Biofilm Formation of Staphylococcus aureus on Different Types of Surfaces Using Microbubbles.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.langmuir.3c02773}, pmid = {38198688}, issn = {1520-5827}, abstract = {Bacterial fouling and biofilm formation on surfaces have been ongoing problems in real life as well as in the medical field. Different approaches have been taken to tackle the issues, from costly surface modification to antibiotic-delivering strategies. In this study, we examined the potential of using stabilized microbubbles (MBs) to shield against bacterial adhesion. Three types of surfaces were tested: hydrophilic glass (hydrophilic surface), neutral hydrophobic polystyrene (PS)-coated surfaces, and negatively charged hydrophobic octadecyltrichlorosilane (OTS)-coated surfaces. By evaluating the colony-forming unit (CFU) values from each surface, MBs stabilized by 0.05 mM SDS were shown to only produce significant reduction of Staphylococcus aureus adhesion on PS surfaces, up to 60.29 and 82.32% compared to no-MB PS surfaces, and no-MB uncoated surfaces, correspondingly, due to the appropriate size, stability, and negative charges of the MB shielding layer. On the other hand, OTS coatings had an intrinsic antiadhesion effect (69.83% compared to uncoated surface), given that the negatively charged OTS-aqueous interface or surface porosity nature of the coating prohibited the attachment of MBs, leading to the elimination of the antifouling effect of MBs. Ultimately, MBs gave better shielding results than surface modification when compared to uncoated surfaces and hence can be applied more widely.}, } @article {pmid38196504, year = {2023}, author = {Liu, J and Yang, L and Qu, Y and Seneviratne, G and Qiu, G and Tan, Y and Xu, Z and Kjellerup, BV}, title = {Biofilm research highlights networked globally.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100148}, doi = {10.1016/j.bioflm.2023.100148}, pmid = {38196504}, issn = {2590-2075}, } @article {pmid38196503, year = {2023}, author = {Goeres, DM and Velez-Justiniano, YA and Kjellerup, BV and McLean, RJ}, title = {Biofilm and human spaceflight.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100150}, pmid = {38196503}, issn = {2590-2075}, } @article {pmid38194503, year = {2024}, author = {Du, C and Woolcott, S and Wahba, AS and Hamry, SR and Odette, WL and Thibodeaux, CJ and Marchand, P and Mauzeroll, J}, title = {Evaluation of Quatsome Morphology, Composition, and Stability for Pseudomonas aeruginosa Biofilm Eradication.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.langmuir.3c02491}, pmid = {38194503}, issn = {1520-5827}, abstract = {Biofilm infections are a major cause of food poisoning and hospital-acquired infections. Quaternary ammonium compounds are a group of effective disinfectants widely used in industry and households, yet their efficacy is lessened when used as antibiofilm agents compared to that against planktonic bacteria. It is therefore necessary to identify alternative formulations of quaternary ammonium compounds to achieve an effective biofilm dispersal. Quaternary ammonium amphiphiles can form vesicular structures termed "quatsomes" in the presence of cholesterol. In addition to their intrinsic antimicrobial properties, quatsomes can also be used for the delivery of other types of antibiotics or biomarkers. In this study, quatsomes were prepared from binary mixtures of cholesterol and mono- or dialkyl-quaternary ammonium compounds; then, the integrity and stability of their vesicular structure were assessed and related to monomer chain number and chain length. The quatsomes were used to treat Pseudomonas aeruginosa biofilms, showing effective antibiofilm abilities comparable to those of their monomers. A systematic liquid chromatography-mass spectrometry method for quantifying quatsome vesicle components was also developed and used to establish the significance of cholesterol in the quatsome self-assembly processes.}, } @article {pmid38193137, year = {2024}, author = {Zhao, ZZ and Wang, J and Liu, X and Wang, Z and Zheng, X and Li, W and Cheng, T and Zhang, J}, title = {N-acyl homoserine lactones lactonase est816 suppresses biofilm formation and periodontitis in rats mediated by Aggregatibacter actinomycetemcomitans.}, journal = {Journal of oral microbiology}, volume = {16}, number = {1}, pages = {2301200}, pmid = {38193137}, issn = {2000-2297}, abstract = {AIMS: The current study aimed to explore the adjuvant therapeutic effect of N-acyl homoserine lactones (AHLs)-lactonase est816 on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biological behaviors and periodontitis progression.

METHODS: The inhibitory properties of est816 were detected by live/dead bacterial staining, scanning electron microscope (SEM), crystal-violet staining and reverse-transcription quantitative PCR (RT-qPCR). Biocompatibility of est816 on human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGEs) was evaluated by CCK8 and ELISA. The ligature-induced periodontitis model was established in rats. Micro computed tomography and immunohistochemical and histological staining served to evaluate the effect of est816 on the prevention of periodontitis in vivo.

RESULTS: est816 significantly attenuated biofilm formation, reduced the mRNA expression of cytolethal distending toxin, leukotoxin and poly-N-acetyl glucosamine (PNAG) and downregulated expressions of interleukin-6 and tumor necrosis factor-α with low cell toxicity. In vivo investigations revealed est816 decreased alveolar bone resorption, suppressed matrix metalloproteinase-9 expression and increased osteoprotegerin expression.

CONCLUSION: est816 inhibited A. actinomycetemcomitans biofilm formation and virulence release, resulting in anti-inflammation and soothing of periodontitis in rats, indicating that est816 could be investigated in further research on periodontal diseases.}, } @article {pmid38191097, year = {2024}, author = {Nie, M and Alejandro Valdes-Pena, M and Frohock, BH and Smits, E and Daiker, JC and Gilbertie, JM and Schnabel, LV and Pierce, JG}, title = {Expanded Library of Novel 2,3-Pyrrolidinedione Analogues Exhibit Anti-biofilm Activity.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {}, number = {}, pages = {129609}, doi = {10.1016/j.bmcl.2024.129609}, pmid = {38191097}, issn = {1464-3405}, abstract = {Herein we report a new library of 2,3-pyrrolidinedione analogues that expands on our previous report on the antimicrobial studies of this heterocyclic scaffold. The novel 2,3-pyrrolidinediones reported herein have been evaluated against S. aureus and methicillin-resistant S. aureus (MRSA) biofilms, and this work constitutes our first report on the antibiofilm properties of this class of compounds. The antibiofilm activity of these 2,3-pyrrolidinediones has been assessed through minimum biofilm eradication concentration (MBEC) and minimum biofilm inhibition concentration (MBIC) assays. The compounds displayed antibiofilm properties and represent intriguing scaffolds for further optimization and development.}, } @article {pmid38188636, year = {2023}, author = {Pai, L and Patil, S and Liu, S and Wen, F}, title = {A growing battlefield in the war against biofilm-induced antimicrobial resistance: insights from reviews on antibiotic resistance.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1327069}, pmid = {38188636}, issn = {2235-2988}, mesh = {Humans ; *Anti-Bacterial Agents/pharmacology/therapeutic use ; *Drug Resistance, Bacterial ; Azithromycin ; Biofilms ; Colistin ; }, abstract = {Biofilms are a common survival strategy employed by bacteria in healthcare settings, which enhances their resistance to antimicrobial and biocidal agents making infections difficult to treat. Mechanisms of biofilm-induced antimicrobial resistance involve reduced penetration of antimicrobial agents, increased expression of efflux pumps, altered microbial physiology, and genetic changes in the bacterial population. Factors contributing to the formation of biofilms include nutrient availability, temperature, pH, surface properties, and microbial interactions. Biofilm-associated infections can have serious consequences for patient outcomes, and standard antimicrobial therapies are often ineffective against biofilm-associated bacteria, making diagnosis and treatment challenging. Novel strategies, including antibiotics combination therapies (such as daptomycin and vancomycin, colistin and azithromycin), biofilm-targeted agents (such as small molecules (LP3134, LP3145, LP4010, LP1062) target c-di-GMP), and immunomodulatory therapies (such as the anti-PcrV IgY antibodies which target Type IIIsecretion system), are being developed to combat biofilm-induced antimicrobial resistance. A multifaceted approach to diagnosis, treatment, and prevention is necessary to address this emerging problem in healthcare settings.}, } @article {pmid38188584, year = {2023}, author = {Wang, M and Zheng, Y and Yin, C and Dai, S and Fan, X and Jiang, Y and Liu, X and Fang, J and Yi, B and Zhou, Q and Wang, T}, title = {Recent Progress in antibacterial hydrogel coatings for targeting biofilm to prevent orthopedic implant-associated infections.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1343202}, pmid = {38188584}, issn = {1664-302X}, abstract = {The application of orthopedic implants for bone tissue reconstruction and functional restoration is crucial for patients with severe bone fractures and defects. However, the abiotic nature of orthopedic implants allows bacterial adhesion and colonization, leading to the formation of bacterial biofilms on the implant surface. This can result in implant failure and severe complications such as osteomyelitis and septic arthritis. The emergence of antibiotic-resistant bacteria and the limited efficacy of drugs against biofilms have increased the risk of orthopedic implant-associated infections (OIAI), necessitating the development of alternative therapeutics. In this regard, antibacterial hydrogels based on bacteria repelling, contact killing, drug delivery, or external assistance strategies have been extensively investigated for coating orthopedic implants through surface modification, offering a promising approach to target biofilm formation and prevent OIAI. This review provides an overview of recent advancements in the application of antibacterial hydrogel coatings for preventing OIAI by targeting biofilm formation. The topics covered include: (1) the mechanisms underlying OIAI occurrence and the role of biofilms in exacerbating OIAI development; (2) current strategies to impart anti-biofilm properties to hydrogel coatings and the mechanisms involved in treating OIAI. This article aims to summarize the progress in antibacterial hydrogel coatings for OIAI prevention, providing valuable insights and facilitating the development of prognostic markers for the design of effective antibacterial orthopedic implants.}, } @article {pmid38185942, year = {2024}, author = {Zayed, N and Munjaković, H and Aktan, MK and Simoens, K and Bernaerts, K and Boon, N and Braem, A and Pamuk, F and Saghi, M and Van Holm, W and Fidler, A and Gašperšič, R and Teughels, W}, title = {Electrolyzed Saline Targets Biofilm Periodontal Pathogens In Vitro.}, journal = {Journal of dental research}, volume = {}, number = {}, pages = {220345231216660}, doi = {10.1177/00220345231216660}, pmid = {38185942}, issn = {1544-0591}, abstract = {Preventing the development and recurrence of periodontal diseases often includes antimicrobial mouthrinses to control the growth of the periodontal pathogens. Most antimicrobials are nonselective, targeting the symbiotic oral species as well as the dysbiosis-inducing ones. This affects the overall microbial composition and metabolic activity and consequently the host-microbe interactions, which can be detrimental (associated with inflammation) or beneficial (health-associated). Consequently, guiding the antimicrobial effect for modulating the microbial composition to a health-associated one should be considered. For such an approach, this study investigated electrolyzed saline as a novel rinse. Electrolyzed saline was prepared from sterile saline using a portable electrolysis device. Multispecies oral homeostatic and dysbiotic biofilms were grown on hydroxyapatite discs and rinsed daily with electrolyzed saline (EOS). Corresponding positive (NaOCl) and negative (phosphate-buffered saline) controls were included. After 3 rinses, biofilms were analyzed with viability quantitative polymerase chain reaction and scanning electron microscopy. Supernatants of rinsed biofilms were used for metabolic activity analysis (high-performance liquid chromatography) through measuring organic acid content. In addition, human oral keratinocytes (HOKs) were exposed to EOS to test biocompatibility (cytotoxicity and inflammation induction) and also to rinsed biofilms to assess their immunogenicity after rinsing. Rinsing the dysbiotic biofilms with EOS could reduce the counts of the pathobionts (>3 log10 Geq/mm[2] reduction) and avert biofilm dysbiosis (≤1% pathobiont abundance), leading to the dominance of commensal species (≥99%), which altered both biofilm metabolism and interleukin 8 (IL-8) induction in HOKs. EOS had no harmful effects on homeostatic biofilms. The scanning electron micrographs confirmed the same. In addition, tested concentrations of EOS did not have any cytotoxic effects and did not induce IL-8 production in HOKs. EOS showed promising results for diverting dysbiosis in in vitro rinsed biofilms and controlling key periopathogens, with no toxic effects on commensal species or human cells. This novel rinsing should be considered for clinical applications.}, } @article {pmid38185395, year = {2024}, author = {Pauzé-Foixet, J and Mathieu-Denoncourt, A and Duperthuy, M}, title = {Elevated concentrations of polymyxin B elicit a biofilm-specific resistance mechanism in Vibrio cholerae.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104179}, doi = {10.1016/j.resmic.2023.104179}, pmid = {38185395}, issn = {1769-7123}, abstract = {Vibrio cholerae can form biofilms in the aquatic environment and in the human intestine, facilitating the release of hyper-infectious aggregates. Due to the increasing antibiotic resistance, alternatives need to be found. One of these alternatives is antimicrobial peptides, including polymyxin B (PmB). In this study, we first investigated the resistance of V. cholerae O1 El Tor strain A1552 to various antimicrobials under aerobic and anaerobic conditions. An increased resistance to PmB is observed in anaerobiosis, with a 3-fold increase in the dose required for 50% growth inhibition. We then studied the impact of the PmB on the formation and the degradation of V. cholerae biofilms to PmB. Our results show that PmB affects more efficiently biofilm formation under anaerobic conditions. On the other hand, preformed biofilms are susceptible to degradation by PmB at concentrations close to the minimum inhibitory concentration. At higher concentrations, we observean opacification of the biofilm structures within 20 min post-treatment, suggesting a densification of the structure. This densification does not seem to result from the overexpression of matrix genes but rather from DNA release through massive cell lysis, likely forming a protective shield that limits the penetration of the PmB into the biofilm.}, } @article {pmid38185086, year = {2024}, author = {Su, D and He, X and Zhou, J and Yuan, C and Bai, X}, title = {Facet-dependent haloperoxidase-like activities of CeO2 nanoparticles contribute to their excellent biofilm formation suppression abilities.}, journal = {Journal of hazardous materials}, volume = {465}, number = {}, pages = {133433}, doi = {10.1016/j.jhazmat.2024.133433}, pmid = {38185086}, issn = {1873-3336}, abstract = {Biofilms adhering to different surfaces have significant negative impacts in various fields. Cerium oxide nanoparticles can serve as mimics of haloperoxidase for biological biofilm inhibition applications. The regulation of the exposed facet of CeO2 nanoparticles influences their efficiency in various catalytic processes. However, there is still a lack of systematic studies on the facet-dependent haloperoxidase-like activity of CeO2. In the present study, the facet-dependent haloperoxidase activities and antibiofilm performance of CeO2 nanoparticles were elucidated through experiment analysis and density function theory calculation. The as-prepared CeO2 nanoparticles inhibited bacterial survival and catalyzed the oxidative bromination of quorum sensing signaling molecules, achieving biofilm inhibition performance. The antibacterial and biofilm formation suppression abilities were consistent with their haloperoxidase activities. The {111} - and {110} -facet CeO2 nanopolyhedra, as well as the {110} - and {100} -facet CeO2 nanorods, which had higher haloperoxidase activity showed better antibiofilm performance than the {100} -facet CeO2 cubes. The present findings provide a comprehensive understanding of the facet-dependent haloperoxidase-like activity of CeO2. Furthermore, engineering CeO2 morphologies with different crystal facets may represent a novel method for significantly adjusting their haloperoxidase-like activity.}, } @article {pmid38183636, year = {2024}, author = {Kim, J and Stechmiller, J and Weaver, M and James, G and Stewart, PS and Lyon, D}, title = {Associations among wound-related factors including biofilm, wound-related symptoms and systemic inflammation in older adults with chronic venous leg ulcers (CVLU).}, journal = {Advances in wound care}, volume = {}, number = {}, pages = {}, doi = {10.1089/wound.2023.0028}, pmid = {38183636}, issn = {2162-1918}, abstract = {OBJECTIVE: The purposes of this observational prospective study were to 1) characterize the wound related factors (wound area, the presence of biofilm, and total bacteria), wound-related symptoms (fatigue, pain, exudate, itching, and edema or swelling) and systemic inflammation (level of serum CRP), and 2) explore associations between wound related factors, wound-related symptoms, and systemic inflammation in older individuals with chronic venous leg ulcers (CVLU) over 8 weeks of wound treatment.

APPROACH: A total of 117 participants who received standardized care (weekly sharp debridement) for a chronic venous ulcer were enrolled. We collected clinical data every two weeks during the 8 weeks of the study period or until the wound was healed (if healed prior to eight weeks). Associations among variables were estimated using a Bayesian approach applied to general linear mixed models.

RESULTS: Based on Bayes Factor (BF) value, there was extremely strong evidence for the association of biofilm with mean total bacteria (BF>1000). There was moderate evidence of a direct association between biofilm presence and levels of C-reactive protein (CRP) (BF 4.3) and moderate evidence of direct associations between biofilm and wound-related symptoms; pain and exudate (BF 5.12, 8.49 respectively).

INNOVATION: Wound-related symptoms and the level of systemic CRP were associated with biofilm among patients who were receiving weekly sharp debridement. Symptom severity associated with CVLUs requires assessment and management of wound-related factors and levels of inflammation in addition to symptom assessment.

CONCLUSION: This study is the first to examine associations among biofilm, as a wound-related factors, systemic inflammation, wound-related symptoms, and wound healing in clinical settings. Symptom severity, level of systemic CRP, and wound-related factors should be considered as well as assessment of biofilm in CVLU in older individuals with CVLU.}, } @article {pmid38183487, year = {2024}, author = {Huo, LC and Liu, NY and Wang, CJ and Luo, Y and Liu, JX}, title = {Lonicera japonica protects Pelodiscus sinensis by inhibiting the biofilm formation of Aeromonas hydrophila.}, journal = {Applied microbiology and biotechnology}, volume = {108}, number = {1}, pages = {1-14}, pmid = {38183487}, issn = {1432-0614}, abstract = {Aquaculture has suffered significant financial losses as a result of the infection of zoonotic Aeromonas hydrophila, which has a high level of resistance to classic antibiotics. In this study, we isolated an A. hydrophila strain B3 from diseased soft-shelled turtle (Pelodiscus sinensis), which is one of the most commercially significant freshwater farmed reptiles in East Asia, and found that A. hydrophila was its dominant pathogen. To better understand the inhibition effect and action mechanism of Chinese herbs on A. hydrophila, we conducted Chinese herbs screening and found that Lonicera japonica had a significant antibacterial effect on A. hydrophila B3. Experimental therapeutics of L. japonica on soft-shelled turtle showed that the supplement of 1% L. japonica to diet could significantly upregulate the immunity-related gene expression of soft-shelled turtle and protect soft-shelled turtle against A. hydrophila infection. Histopathological section results validated the protective effect of L. japonica. As the major effective component of L. japonica, chlorogenic acid demonstrated significant inhibitory effect on the growth of A. hydrophila with MIC at 6.4 mg/mL. The in vitro assay suggested that chlorogenic acid could inhibit the hemolysin/protease production and biofilm formation of A. hydrophila and significantly decrease the expression of quorum sensing, biofilm formation, and hemolysin-related genes in A. hydrophila. Our results showed that the Chinese herb L. japonica would be a promising candidate for the treatment of A. hydrophila infections in aquaculture, and it not only improves the immune response of aquatic animals but also inhibits the virulence factor (such as biofilm formation) expression of A. hydrophila. KEY POINTS: • A. hydrophila was the dominant pathogen of the diseased soft-shelled turtle. • L. japonica can protect soft-shelled turtle against A. hydrophila infection. • Chlorogenic acid inhibits the growth and biofilm formation of A. hydrophila.}, } @article {pmid38183478, year = {2024}, author = {Yoon, Y and Aziz, AA and Chang, IS and Kim, B}, title = {Prevalence of Escherichia coli in electrogenic biofilm on activated carbon in microbial fuel cell.}, journal = {Applied microbiology and biotechnology}, volume = {108}, number = {1}, pages = {1-10}, pmid = {38183478}, issn = {1432-0614}, support = {NRF-2022R1C1C1007791//National Research Foundation of Korea/ ; NRF-2021R1A5A1028138//National Research Foundation of Korea/ ; }, abstract = {For a better understanding of the distribution of depth-dependent electrochemically active bacteria at in the anode zone, a customized system in a microbial fuel cell (MFC) packed with granular activated carbon (GAC) was developed and subsequently optimized via electrochemical tests. The constructed MFC system was sequentially operated using two types of matrice solutions: artificially controlled compositions (i.e., artificial wastewater, AW) and solutions obtained directly from actual sewage-treating municipal plants (i.e., municipal wastewater, MW). Notably, significant difference(s) of system efficiencies between AW or MW matrices were observed via performance tests, in that the electricity production capacity under MW matrices is < 25% that of the AW matrices. Interestingly, species of Escherichia coli (E. coli) sampled from the GAC bed (P1: deeper region in GAC bed, P2: shallow region of GAC near electrolytes) exhibited an average relative abundance of 75 to 90% in AW and a relative abundance of approximately 10% in MW, while a lower relative abundance of E. coli was found in both the AW and MW anolyte samples (L). Moreover, similar bacterial communities were identified in samples P1 and P2 for both the AW and MW solutions, indicating a comparable distribution of bacterial communities over the anode area. These results provide new insights into E. coli contribution in power production for the GAC-packed MFC systems (i.e., despite the low contents of Geobacter (> 8%) and Shewanella (> 1%)) for future applications in sustainable energy research. KEY POINTS: • A microbial community analysis for depth-dependence in biofilm was developed. • The system was operated with two matrices; electrochemical performance was assessed. • E. coli spp. was distinctly found in anode zone layers composed of activated carbon.}, } @article {pmid38182675, year = {2024}, author = {Zhou, Y and Meng, F and Ochieng, B and Xu, J and Zhang, L and Kimirei, IA and Feng, M and Zhu, L and Wang, J}, title = {Climate and Environmental Variables Drive Stream Biofilm Bacterial and Fungal Diversity on Tropical Mountainsides.}, journal = {Microbial ecology}, volume = {87}, number = {1}, pages = {28}, pmid = {38182675}, issn = {1432-184X}, abstract = {High mountain freshwater systems are particularly sensitive to the impacts of global warming and relevant environmental changes. Microorganisms contribute substantially to biogeochemical processes, yet their distribution patterns and driving mechanism in alpine streams remain understudied. Here, we examined the bacterial and fungal community compositions in stream biofilm along the elevational gradient of 745-1874 m on Mt. Kilimanjaro and explored their alpha and beta diversity patterns and the underlying environmental drivers. We found that the species richness and evenness monotonically increased towards higher elevations for bacteria, while were non-significant for fungi. However, both bacterial and fungal communities showed consistent elevational distance-decay relationships, i.e., the dissimilarity of assemblage composition increased with greater elevational differences. Bacterial alpha diversity patterns were mainly affected by chemical variables such as total nitrogen and phosphorus, while fungi were affected by physical variables such as riparian shading and stream width. Notably, climatic variables such as mean annual temperature strongly affected the elevational succession of bacterial and fungal community compositions. Our study is the first exploration of microbial biodiversity and their underlying driving mechanisms for stream ecosystems in tropical alpine regions. Our findings provide insights on the response patterns of tropical aquatic microbial community composition and diversity under climate change.}, } @article {pmid38180520, year = {2024}, author = {Pool-Yam, L and Ramón-Sierra, J and Oliva, AI and Zamora-Bustillos, R and Ortiz-Vázquez, E}, title = {Effect of conA-unbound proteins from Melipona beecheii honey on the formation of Pseudomonas aeruginosa ATCC 27853 biofilm.}, journal = {Archives of microbiology}, volume = {206}, number = {1}, pages = {54}, pmid = {38180520}, issn = {1432-072X}, support = {17678//Tecnológico Nacional de México/ ; }, abstract = {Pseudomonas aeruginosa is an opportunistic bacterium that can form a biofilm with the ability to colonize different surfaces and for increasing resistance to antibiotics. An alternative to solve this problem may be the use of non-glucose/mannose glycosylated proteins from Melipona beecheii honey, which are capable of inhibiting the growth of this pathogen. In this work, the antibiofilm activity of the conA-unbound protein fraction (F1) from M. beecheii was evaluated. The crude protein extract (CPE) and the F1 fraction inhibited the P. aeruginosa biofilm growth above 80% at 4 and 1.3 µg/mL, respectively. These proteins affected the structure of the biofilm, as well as fleQ and fleR gene expressions involved in the formation and regulation of the P. aeruginosa biofilm. The results demonstrated that the F1 fraction proteins of M. beecheii honey inhibit and affect the formation of the P. aeruginosa biofilm.}, } @article {pmid38179460, year = {2023}, author = {Luo, ZX and Li, Y and Liu, MF and Zhao, R}, title = {Ciprofloxacin enhances the biofilm formation of Staphylococcus aureus via an agrC-dependent mechanism.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1328947}, pmid = {38179460}, issn = {1664-302X}, abstract = {Staphylococcus aureus readily forms biofilms on host tissues and medical devices, enabling its persistence in chronic infections and resistance to antibiotic therapy. The accessory gene regulator (Agr) quorum sensing system plays a key role in regulating S. aureus biofilm formation. This study reveals the widely used fluoroquinolone antibiotic, ciprofloxacin, strongly stimulates biofilm formation in methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and clinical isolates with diverse genetic backgrounds. Crystal violet staining indicated that ciprofloxacin induced a remarkable 12.46- to 15.19-fold increase in biofilm biomass. Confocal laser scanning microscopy revealed that ciprofloxacin induced denser biofilms. Phenotypic assays suggest that ciprofloxacin may enhance polysaccharide intercellular adhesin production, inhibit autolysis, and reduce proteolysis during the biofilm development, thus promoting initial adhesion and enhancing biofilm stability. Mechanistically, ciprofloxacin significantly alters the expression of various biofilm-related genes (icaA, icaD, fnbA, fnbB, eap, emp) and regulators (agrA, saeR). Gene knockout experiments revealed that deletion of agrC, rather than saeRS, abolishes the ciprofloxacin-induced enhancement of biofilm formation, underscoring the key role of agrC. Thermal shift assays showed ciprofloxacin binds purified AgrC protein, thereby inhibiting the Agr system. Molecular docking results further support the potential interaction between ciprofloxacin and AgrC. In summary, subinhibitory concentrations of ciprofloxacin stimulate S. aureus biofilm formation via an agrC-dependent pathway. This inductive effect may facilitate local infection establishment and bacterial persistence, ultimately leading to therapeutic failure.}, } @article {pmid38178319, year = {2024}, author = {Moran, CL and Debowski, A and Vrielink, A and Stubbs, K and Sarkar-Tyson, M}, title = {N-acetyl-β-hexosaminidase activity is important for chitooligosaccharide metabolism and biofilm formation in Burkholderia pseudomallei.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16571}, pmid = {38178319}, issn = {1462-2920}, support = {//Australian Government Research Training Program Scholarship/ ; }, abstract = {Burkholderia pseudomallei is a saprophytic Gram-negative bacillus that can cause the disease melioidosis. Although B. pseudomallei is a recognised member of terrestrial soil microbiomes, little is known about its contribution to the saprophytic degradation of polysaccharides within its niche. For example, while chitin is predicted to be abundant within terrestrial soils the chitinolytic capacity of B. pseudomallei is yet to be defined. This study identifies and characterises a putative glycoside hydrolase, bpsl0500, which is expressed by B. pseudomallei K96243. Recombinant BPSL0500 was found to exhibit activity against substrate analogues and GlcNAc disaccharides relevant to chitinolytic N-acetyl-β-d-hexosaminidases. In B. pseudomallei, bpsl0500 was found to be essential for both N-acetyl-β-d-hexosaminidase activity and chitooligosaccharide metabolism. Furthermore, bpsl0500 was also observed to significantly affect biofilm deposition. These observations led to the identification of BPSL0500 activity against model disaccharide linkages that are present in biofilm exopolysaccharides, a feature that has not yet been described for chitinolytic enzymes. The results in this study indicate that chitinolytic N-acetyl-β-d-hexosaminidases like bpsl0500 may facilitate biofilm disruption as well as chitin assimilation, providing dual functionality for saprophytic bacteria such as B. pseudomallei within the competitive soil microbiome.}, } @article {pmid38178276, year = {2024}, author = {Wang, X and Wang, D and Lu, H and Wang, X and Wang, X and Su, J and Xia, G}, title = {Strategies to Promote the Journey of Nanoparticles Against Biofilm-Associated Infections.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2305988}, doi = {10.1002/smll.202305988}, pmid = {38178276}, issn = {1613-6829}, support = {2016YFA0201504//National Key Research and Development Program of China/ ; 2021-I2M-1-070//CAMS Innovation Fund for Medical Sciences/ ; 2022-I2M-2-002//CAMS Innovation Fund for Medical Sciences/ ; }, abstract = {Biofilm-associated infections are one of the most challenging healthcare threats for humans, accounting for 80% of bacterial infections, leading to persistent and chronic infections. The conventional antibiotics still face their dilemma of poor therapeutic effects due to the high tolerance and resistance led by bacterial biofilm barriers. Nanotechnology-based antimicrobials, nanoparticles (NPs), are paid attention extensively and considered as promising alternative. This review focuses on the whole journey of NPs against biofilm-associated infections, and to clarify it clearly, the journey is divided into four processes in sequence as 1) Targeting biofilms, 2) Penetrating biofilm barrier, 3) Attaching to bacterial cells, and 4) Translocating through bacterial cell envelope. Through outlining the compositions and properties of biofilms and bacteria cells, recent advances and present the strategies of each process are comprehensively discussed to combat biofilm-associated infections, as well as the combined strategies against these infections with drug resistance, aiming to guide the rational design and facilitate wide application of NPs in biofilm-associated infections.}, } @article {pmid38175479, year = {2024}, author = {Vuotto, C and Donelli, G and Buckley, A and Chilton, C}, title = {Clostridioides difficile Biofilm.}, journal = {Advances in experimental medicine and biology}, volume = {1435}, number = {}, pages = {249-272}, pmid = {38175479}, issn = {0065-2598}, mesh = {Humans ; *Clostridioides difficile ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Drug Tolerance ; Immune Tolerance ; }, abstract = {Clostridioides difficile infection (CDI), previously Clostridium difficile infection, is a symptomatic infection of the large intestine caused by the spore-forming anaerobic, gram-positive bacterium Clostridioides difficile. CDI is an important healthcare-associated disease worldwide, characterized by high levels of recurrence, morbidity, and mortality. CDI is observed at a higher rate in immunocompromised patients after antimicrobial therapy, with antibiotics disrupting the commensal microbiota and promoting C. difficile colonization of the gastrointestinal tract.A rise in clinical isolates resistant to multiple antibiotics and the reduced susceptibility to the most commonly used antibiotic molecules have made the treatment of CDI more complicated, allowing the persistence of C. difficile in the intestinal environment.Gut colonization and biofilm formation have been suggested to contribute to the pathogenesis and persistence of C. difficile. In fact, biofilm growth is considered as a serious threat because of the related antimicrobial tolerance that makes antibiotic therapy often ineffective. This is the reason why the involvement of C. difficile biofilm in the pathogenesis and recurrence of CDI is attracting more and more interest, and the mechanisms underlying biofilm formation of C. difficile as well as the role of biofilm in CDI are increasingly being studied by researchers in the field.Findings on C. difficile biofilm, possible implications in CDI pathogenesis and treatment, efficacy of currently available antibiotics in treating biofilm-forming C. difficile strains, and some antimicrobial alternatives under investigation will be discussed here.}, } @article {pmid38175302, year = {2024}, author = {Huang, B and Liu, C and Yang, J and Xiang, E and Ivanovski, S and Han, P}, title = {Saliva biofilm-derived outer membrane vesicles regulate biofilm formation and immune response of oral epithelial cells on titanium surfaces.}, journal = {Clinical oral investigations}, volume = {28}, number = {1}, pages = {75}, pmid = {38175302}, issn = {1436-3771}, mesh = {Humans ; *Saliva ; Interleukin-6 ; Titanium/pharmacology ; *Peri-Implantitis ; Cytokines ; Biofilms ; Epithelial Cells ; Immunity ; RNA, Messenger ; }, abstract = {OBJECTIVES: While the significant roles of outer membrane vesicles (OMVs) from individual oral bacterial species in bacterial-host interactions are known, the involvement of saliva biofilm-derived OMVs in peri-implant disease pathogenesis remains unclear. This study aimed to investigate the effect of saliva biofilm-derived OMVs on regulating saliva biofilm formation and modulating the immune response of the epithelial cells on titanium surfaces.

MATERIALS AND METHODS: Saliva derived biofilms were cultured on tissue culture plates (TCP) for 4 days using pooled saliva from four healthy donors. OMVs secreted from the TCP bound biofilm (referred to as OMVs or healthy saliva biofilm OMVs) were enriched using the size-exclusion chromatography method. We then evaluated the effects of these OMVs on the viability, metabolic activity, and the presence of oral pathogens in saliva biofilm grown on titanium discs for 24 h and 72 h. Furthermore, the impact of OMVs on the mRNA expression and inflammatory cytokines [interleukin (IL)-6, IL-1α, and monocyte chemoattractant protein-1 (MCP-1)] in human oral epithelial cells (OKF6/TERT-2) was investigated using RT-qPCR and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS: Healthy saliva biofilm OMVs improved the biomass and activity of saliva biofilm cultured on the titanium surfaces, with inhibited Porphyromonas gingivalis and Fusobacterium nucleatum, and enhanced Streptococcus mutans expression. Additionally, OMVs increased pro-inflammatory cytokine IL-6 mRNA and IL-6 cytokine expression in human oral epithelial cells. However, IL-1α and MCP-1 cytokines were inhibited 24-hour post-incubation with OMVs.

CONCLUSION: Healthy saliva biofilm derived OMVs regulate the activity and pathogen composition of biofilms formed on titanium, while modulating the secretion of pro-inflammation factors of oral epithelial cells grown on titanium surfaces.

CLINICAL RELEVANCE: Healthy saliva biofilm OMVs may regulate the early biofilm formation on abutment surfaces and modulate epithelial cell immune response, which may alter the peri-implant niche and participate in the pathogenesis of peri-implant disease.}, } @article {pmid38174900, year = {2024}, author = {Somarathne, RP and Misra, SK and Kariyawasam, CS and Kessl, JJ and Sharp, JS and Fitzkee, NC}, title = {Exploring Residue-Level Interactions between the Biofilm-Driving R2ab Protein and Polystyrene Nanoparticles.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.langmuir.3c02609}, pmid = {38174900}, issn = {1520-5827}, abstract = {In biological systems, proteins can bind to nanoparticles to form a "corona" of adsorbed molecules. The nanoparticle corona is of significant interest because it impacts an organism's response to a nanomaterial. Understanding the corona requires knowledge of protein structure, orientation, and dynamics at the surface. A residue-level mapping of protein behavior on nanoparticle surfaces is needed, but this mapping is difficult to obtain with traditional approaches. Here, we have investigated the interaction between R2ab and polystyrene nanoparticles (PSNPs) at the level of individual residues. R2ab is a bacterial surface protein from Staphylococcus epidermidis and is known to interact strongly with polystyrene, leading to biofilm formation. We have used mass spectrometry after lysine methylation and hydrogen-deuterium exchange (HDX) NMR spectroscopy to understand how the R2ab protein interacts with PSNPs of different sizes. Lysine methylation experiments reveal subtle but statistically significant changes in methylation patterns in the presence of PSNPs, indicating altered protein surface accessibility. HDX rates become slower overall in the presence of PSNPs. However, some regions of the R2ab protein exhibit faster than average exchange rates in the presence of PSNPs, while others are slower than the average behavior, suggesting conformational changes upon binding. HDX rates and methylation ratios support a recently proposed "adsorbotope" model for PSNPs, wherein adsorbed proteins consist of unfolded anchor points interspersed with partially structured regions. Our data also highlight the challenges of characterizing complex protein-nanoparticle interactions using these techniques, such as fast exchange rates. While providing insights into how R2ab adsorbs onto PSNP surfaces, this research emphasizes the need for advanced methods to comprehend residue-level interactions in the nanoparticle corona.}, } @article {pmid38174123, year = {2024}, author = {Chen, P and Zeng, J and Hong, F and Li, C and Wang, H and Yu, X}, title = {The importance of biofilm contamination control for dental unit waterlines: a multicenter assessment of the microbiota diversity of biofilm in dental unit waterlines.}, journal = {Journal of oral microbiology}, volume = {16}, number = {1}, pages = {2299496}, pmid = {38174123}, issn = {2000-2297}, abstract = {BACKGROUND: The biofilm formation in Dental Unit Waterlines (DUWLs) could become an important cause of infection during dental care, which could put immunocompromised individuals at risk of cross-infection. The aim of this study was to characterize the microbial communities of biofilms among DUWLs using high-throughput sequencing technology.

METHODS: Twenty-nine biofilm samples were obtained from 24 dental chair units at 5 hospitals and 2 dental clinics. The genomic DNA of the samples was extracted, then 16S rDNA and ITS2 gene were amplified and sequenced. Alpha-diversity and Beta-diversity were calculated with QIIME2 and the Kruskal - Wallis H-test was adopted for statistical analysis.

RESULTS: Microbial communities with a high diversity of bacteria (377 genera) and fungi (83 genera) were detected in the biofilm samples. The dominant phylum of bacteria was Proteobacteria (93.27%) and that of fungi was Basidiomycota (68.15%). Potential human pathogens were detected including 7 genera of bacteria (Pseudomonas, Stenotrophomonas, Hafnia-Obesumbacterium, Burkholderia-Caballeronia-Paraburkholderia, Ralstonia, Enterobacter, Klebsiella) and 6 genera of fungi (Malassezia, Candida, Alternaria, Cryptococcus, Rhodotorula, Rhinocladiella).

CONCLUSIONS: This multicenter assessment revealed the infectious risk during dental care. It emphasized the importance of biofilm control due to biofilm accumulation and multiple kinds of opportunistic pathogens in DUWLs.}, } @article {pmid38172665, year = {2024}, author = {Farshadzadeh, Z and Pourhajibagher, M and Taheri, B and Ekrami, A and Modarressi, MH and Azimzadeh, M and Bahador, A}, title = {Retraction Note: Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1 L against Acinetobacter baumannii: an in vivo wound healing model.}, journal = {BMC microbiology}, volume = {24}, number = {1}, pages = {12}, doi = {10.1186/s12866-023-03168-2}, pmid = {38172665}, issn = {1471-2180}, } @article {pmid38172225, year = {2024}, author = {Yakoup, AY and Kamel, AG and Elbermawy, Y and Abdelsattar, AS and El-Shibiny, A}, title = {Characterization, antibacterial, and cytotoxic activities of silver nanoparticles using the whole biofilm layer as a macromolecule in biosynthesis.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {364}, pmid = {38172225}, issn = {2045-2322}, support = {41909//Science and Technology Development Fund/ ; }, abstract = {Recently, multi-drug resistant (MDR) bacteria are responsible for a large number of infectious diseases that can be life-threatening. Globally, new approaches are targeted to solve this essential issue. This study aims to discover novel antibiotic alternatives by using the whole components of the biofilm layer as a macromolecule to synthesize silver nanoparticles (AgNPs) as a promising agent against MDR. In particular, the biosynthesized biofilm-AgNPs were characterized using UV-Vis spectroscopy, electron microscopes, Energy Dispersive X-ray (EDX), zeta sizer and potential while their effect on bacterial strains and normal cell lines was identified. Accordingly, biofilm-AgNPs have a lavender-colored solution, spherical shape, with a size range of 20-60 nm. Notably, they have inhibitory effects when used on various bacterial strains with concentrations ranging between 12.5 and 25 µg/mL. In addition, they have an effective synergistic effect when combined with phage ZCSE9 to inhibit and kill Salmonella enterica with a concentration of 3.1 µg/mL. In conclusion, this work presents a novel biosynthesis preparation of AgNPs using biofilm for antibacterial purposes to reduce the possible toxicity by reducing the MICs using phage ZCSE9.}, } @article {pmid38172063, year = {2023}, author = {Chen, H and Xu, MM and Sun, YT and Yu, S and Yang, DQ}, title = {[Inhibitory effect of Streptococcus mutans antisense vicK RNA regulating the cariogenicity of oral streptococci multi-species biofilm].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {59}, number = {1}, pages = {64-70}, doi = {10.3760/cma.j.cn112144-20231031-00229}, pmid = {38172063}, issn = {1002-0098}, support = {82100991//National Natural Science Foundation of China/ ; 2021M700627//China Postdoctoral Science Foundation/ ; cstc2021jcyj-bshX0211//Natural Science Foundation Project of Chongqing Science and Technology Commission/ ; 20210124//The Basic Research and Frontiers Exploration Project of Science and Technology Committee of Yuzhong District/ ; 2010010005994583//Chongqing Special Postdoctoral Science Foundation/ ; KJQN202100440//Scientific and Technological Research Program of Chongqing Municipal Education Commission/ ; }, abstract = {Objective: To investigate the inhibitory effects of Streptococcus mutans (Sm) antisense vicK RNA (ASvicK) on the multi-species biofilm formed by three common oral streptococci (Sm, Streptococcus sanguinis, and Streptococcus gordonii) (Sm+Ss+Sg). Methods: ASvicK over-expression strain was constructed by using a recombinant plasmid, and three-species biofilm UA159+Ss+Sg and ASvicK+Ss+Sg were cultured. The phenotypes of biofilm were detected by scanning electron microscopy (SEM). Crystal violet (CV) assay was used to detect biomass of the biofilm. Lactate kit and anthrone-sulfuric acid colorimetric assay were used to determine the abilities of lactic acid production and EPS metabolism, respectively. The proportions of three-species and expression levels of the cariogenic-related genes in biofilms were detected by Taqman fluorescence quantitative PCR (Taqman-qPCR) and quantitative real-time PCR (RT-qPCR). A biofilm demineralization model of human enamel slabs was further constructed, and the hardness of enamel surface was detected. Results: Compared to UA159+Ss+Sg, over-expression of ASvicK could inhibit biofilm formation and lactic acid production in ASvicK+Ss+Sg biofilm significantly by 78.93% (P<0.001) and 62.23% (P<0.001), respectively. With ASvicK over-expression, the amounts of water-insoluble and-soluble glucoses in ASvicK+Ss+Sg biofilm reduced respectively by 39.13% (P<0.001) and 68.00% (P<0.001) compared to the control. And with ASvicK over-expression, the proportion of Sm, the cariogenic bacteria, showed 33.00% reduction (P<0.01) in Sm+Ss+Sg biofilm, and the gene expressions of cariogenic-relative genes vicK/X, gtfB/C/D, and ftf significantly decreased (P<0.05). The micro-hardness value of enamel slabs after demineralization by ASvicK+Ss+Sg biofilm was significantly 1.83 times higher than that of group UA159+Ss+Sg (P<0.001). Conclusions: ASvicK could reduce the Sm proportion and weaken the cariogenicity of oral Streptococcus biofilms, thereby possibly slowing down the progress of caries.}, } @article {pmid38172062, year = {2023}, author = {Huang, S and Du, JY and Li, YJ and Wu, MJ and Chen, S and Jiang, S and Huang, XJ}, title = {[Role and related mechanisms of liasr two-component system in acid tolerance and biofilm formation of Streptococcus mutans].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {59}, number = {1}, pages = {54-63}, doi = {10.3760/cma.j.cn112144-20230902-00130}, pmid = {38172062}, issn = {1002-0098}, support = {81600861//National Natural Science Foundation of China/ ; 2018-KQMJ-02//Scientific Research Foundation for Minjiang Scholars/ ; }, abstract = {Objective: To investigate the role and related mechanisms of the LiaSR two-component system in acid tolerance and biofilm formation abilities of Streptococcus mutans (Sm) 593. Methods: The growth curves of various Sm strains in pH=5.5 brian heart infusion (BHI) medium were analyzed. And colony forming unit (CFU) was also performed to evaluate the acid tolerance of Sm. Laurdan probe, H[+]-K[+]adenosine triphosphate (ATP)ase activity analysis kit, proton permeability assay and real-time fluorescence quantitative PCR (RT-qPCR) were conducted to detect the acid tolerant mechanisms of LiaSR two-component system in Sm. Crystal violet staining, CFU, SYTOX probe and anthrone-sulfuric method were used to analyze the properties and structures of the Sm biofilms. RT-qPCR was conducted to detect the expression levels of underlying regulated genes. Results: The growth of mutants in acidic BHI were inhibited (P<0.05). The acid tolerance of mutants significantly decreased compared to the wild-type strain (P<0.05). In mutants, the activity of H[+]-ATPase (917.06±59.53 and 469.53±47.65) were elevated by 7.22-folds and 3.70-folds compared to the wild-type strain (127.00±50.71) (P<0.001, P<0.001) and the encoded gene atpD (3.39±0.21 and 1.94±0.17) were also elevated by 3.39-folds and 1.94-folds compared to the wild-type strain (1.00±0.15) (P<0.001, P=0.001). The fluidity of mutants (0.18±0.04 and 0.18±0.05) reduced significantly compared to the wild-type strain (0.08±0.05) (P=0.006, P=0.003) and the expression levels of fabM gene were decreased in mutants (0.52±0.11 and 0.57±0.05) by 1/2 (P=0.014, P=0.022). In liaR deletion mutant, the increased proton permeability (4.76±0.01) can also be observed (P<0.001). The total amount of the biofilms of three Sm didn't show significant differences (P>0.05). But the number of viable bacteria of mutants' biofilms were decreased [Sm 593: (1.20±2.80)×10[7] CFU/ml; Sm ΔliaS: (2.95±1.13)×10[7] CFU/ml; Sm ΔliaR: (7.25±1.60)×10[7] CFU/ml] (P=0.001, P=0.024). 18.00-folds and 6.50-folds increases of eDNA could be observed in mutants' biofilms (128.73±15.65 and 46.38±5.52) compared to the wild-type strain (7.16±3.62) (P<0.001, P=0.003). Water-soluble exopolysaccharides could be found up-regulated in liaS deletion mutant (138.73±10.12) (P=0.003) along with the expression level of gtfC gene (1.65±0.39) (P=0.014). The expression level of gtfD were elevated by 47.43-folds and 16.90-folds in mutants (47.43±8.32 and 16.90±3.40) (P<0.001, P=0.01). Conclusions: The LiaSR two-component system can promote the expression of fabM gene and increase the fluidity of Sm which contributes to acid tolerance. The LiaR can also decrease the proton permeability and restrict the entrance of H[+]. The LiaSR two-component system can negatively regulate the production of the extracellular matrix in Sm biofilm.}, } @article {pmid38172061, year = {2023}, author = {Zhang, JX and Li, BL and Zhou, XD and Cheng, L}, title = {[Effect of a novel pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate modified resin adhesive on biofilm formation of Streptococcus mutans and Lactobacillus casei in vitro].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {59}, number = {1}, pages = {45-53}, doi = {10.3760/cma.j.cn112144-20231018-00206}, pmid = {38172061}, issn = {1002-0098}, support = {82071106//National Natural Science Foundation of China/ ; }, abstract = {Objective: To explore the application prospect of a new pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate (DMAEM) modified resin adhesive (DMAEM@RA) in the prevention and treatment of secondary caries. Methods: Five percents DMAEM was added to the resin adhesive to synthesize DMAEM@RA for modifying. Streptococcus mutans (Sm) and Lactobacillus casei (Lc) biofilms were cultured on resin adhesive and 5% DMAEM@RA, respectively. The culture systems were set up at pH=7.4, 6.0, 5.5, and 5.0. The antimicrobial activity of DMAEM@RA was evaluated by quantitative PCR. The effects of DMAEM@RA on biofilm thickness, bacterial amount, and extracellular polysaccharides were studied by scanning electron microscope (SEM) and extracellular polysaccharide staining. Quantitative real-time PCR (qRT-PCR) was used to study the effect of DMAEM@RA on the expression levels of cariogenic genes in Sm. Results: DMAEM@RA could significantly reduce the amount of Sm and Lc under acidic conditions, especially Lc. The logarithmic value of co-cultured Sm decreased significantly from 7.87±0.03 to 7.58±0.01 (t=14.32, P<0.001), while the co-culture Lc decreased from 7.93±0.15 to 7.29±0.04 (t=6.93, P=0.002). SEM observed that the bacteria decreased and the cell fragments appeared after DMAEM treatment. In addition, DMAEM@RA significantly reduced the extracellular polysaccharides in the dual-species biofilm under acidic conditions, from (42.66±7.46) μm[3]/μm[3] to (25.13±3.14) μm[3]/μm[2] at pH=5.0 (t=3.75, P=0.020). DMAEM@RA could significantly up-regulate the expressions of gtfB and gtfC genes in Sm under acidic conditions. At pH=5.0, gtfB and gtfC genes were significantly up-regulated by (14.64±0.44) times and (2.99±0.20) times(t=-42.74，P<0.001;t=-13.55, P<0.001), respectively. Conclusions: The DMAEM modified resin adhesive has a good antibacterial effect under acidic conditions, demonstrating that it has a good potential to prevent the occurrence and development of secondary caries.}, } @article {pmid38170991, year = {2024}, author = {Huang, M-B and Brena, D and Wu, JY and Shelton, M and Bond, VC}, title = {SMR peptide antagonizes Staphylococcus aureus biofilm formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0258323}, doi = {10.1128/spectrum.02583-23}, pmid = {38170991}, issn = {2165-0497}, abstract = {The development of anti-biofilm agents is critical to restoring bacterial sensitivity, directly combating the evolution of resistance, and overall reducing the clinical burden related to pervasive biofilm-mediated infections. Thus, in this study, the SMR peptide, a novel small molecule derived from the HIV Nef protein, was preliminarily explored for anti-biofilm properties. The SMR peptide was shown to effectively target the molecular chaperone DnaK and inhibit biofilm formation in a dose-dependent manner. These results support further investigation into the mechanism of SMR peptide-mediated biofilm formation and inhibition to benefit rational drug design and the identification of therapeutic targets.}, } @article {pmid38170984, year = {2024}, author = {Xiao, Y and Wan, C and Wu, X and Xu, Y and Chen, Y and Rao, L and Wang, B and Shen, L and Han, W and Zhao, H and Shi, J and Zhang, J and Song, Z and Yu, F}, title = {Novel small-molecule compound YH7 inhibits the biofilm formation of Staphylococcus aureus in a sarX-dependent manner.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0056423}, doi = {10.1128/msphere.00564-23}, pmid = {38170984}, issn = {2379-5042}, abstract = {Biofilm-associated infections, characterized by antibiotic resistance and persistence, present a formidable challenge in healthcare. Traditional antibacterial agents prove inadequate against biofilms. In this study, the novel compound YH7 demonstrates potent antibiofilm properties by impeding the adhesion and the polysaccharide intercellular adhesin production of Staphylococcus aureus. Notably, its exceptional efficacy against both methicillin-resistant and methicillin-susceptible strains highlights its broad applicability. This study highlights the potential of YH7 as a novel therapeutic agent to address the pressing issue of biofilm-driven infections.}, } @article {pmid38169688, year = {2023}, author = {Yang, M and Xie, M and Guo, J and Zhang, Y and Qiu, Y and Wang, Z and Du, Y}, title = {Mucus-Permeable Sonodynamic Therapy Mediated Amphotericin B-Loaded PEGylated PLGA Nanoparticles Enable Eradication of Candida albicans Biofilm.}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {7941-7963}, pmid = {38169688}, issn = {1178-2013}, abstract = {BACKGROUND: Candida albicans (C. albicans) forms pathogenic biofilms, and the dense mucus layer secreted by the epithelium is a major barrier to the traditional antibiotic treatment of mucosa-associated C. albicans infections. Herein, we report a novel anti-biofilm strategy of mucus-permeable sonodynamic therapy (mp-SDT) based on ultrasound (US)-mediated amphotericin B-loaded PEGylated PLGA nanoparticles (AmB-NPs) to overcome mucus barrier and enable the eradication of C. albicans biofilm.

METHODS: AmB-NPs were fabricated using ultrasonic double emulsion method, and their physicochemical and sonodynamic properties were determined. The mucus and biofilm permeability of US-mediated AmB-NPs were further investigated. Moreover, the anti-biofilm effect of US-mediated AmB-NPs treatment was thoroughly evaluated on mucus barrier abiotic biofilm, epithelium-associated biotic biofilm, and C. albicans-induced rabbit vaginal biofilms model. In addition, the ultrastructure and secreted cytokines of epithelial cells and the polarization of macrophages were analyzed to investigate the regulation of local cellular immune function by US-mediated AmB-NPs treatment.

RESULTS: Polymeric AmB-NPs display excellent sonodynamic performance with massive singlet oxygen ([1]O2) generation. US-mediated AmB-NPs could rapidly transport through mucus and promote permeability in biofilms, which exhibited excellent eradicating ability to C. albicans biofilms. Furthermore, in the vaginal epithelial cells (VECs)-associated C. albicans biofilm model, the mp-SDT scheme showed the strongest biofilm eradication effect, with up to 98% biofilm re-formation inhibition rate, improved the ultrastructural damage, promoted local immune defense enhancement of VECs, and regulated the polarization of macrophages to the M1 phenotype to enhance macrophage-associated antifungal immune responses. In addition, mp-SDT treatment exhibited excellent therapeutic efficacy against C. albicans-induced rabbit vaginitis, promoted the recovery of mucosal epithelial ultrastructure, and contributed to the reshaping of a healthier vaginal microbiome.

CONCLUSION: The synergistic anti-biofilm strategies of mp-SDT effectively eradicated C. albicans biofilm and simultaneously regulated local antifungal immunity enhancement, which may provide a new approach to treat refractory drug-resistant biofilm-associated mucosal candidiasis.}, } @article {pmid38168504, year = {2024}, author = {El Bestawy, E and El-Hameed, ASA and Fadl, E}, title = {Desalination of seawater using integrated microbial biofilm/cellulose acetate membrane and silver NPs/activated carbon nanocomposite in a continuous mode.}, journal = {Scientific reports}, volume = {14}, number = {1}, pages = {274}, pmid = {38168504}, issn = {2045-2322}, abstract = {The main objective of the present study was to desalinate seawater using Bacillus cereus gravel biofilm and cellulose acetate (CA) membranes with and without silver nanoparticles (AgNPs) as a potent and safe disinfectant for the treated water. Six desalination trials (I, II, III, IV, V and VI) were performed using the proposed biofilm/cellulose membrane. Results confirmed that Bacillus cereus gravel biofilm (microbial desalination) is the optimal system for desalination of seawater. It could achieve 45.0% RE (initial salinity: 44,478 mg/L), after only 3 h compared to the other tested treatments. It could also achieve 42, 42, 57, 43 and 59% RE for TDS, EC, TSS, COD and BOD, respectively. To overcome the problem of the residual salinity and reach complete elimination of salt content for potential reuse, multiple units of the proposed biofilm can be used in sequence. As a general conclusion, the Bacillus cereus biofilm system can be considered as remarkably efficient, feasible, rapid, clean, renewable, durable, environmentally friendly and easily applied technology compared to the very costly and complicated common desalination technologies. Up to our knowledge, this is the first time microbial biofilm was developed and used as an effective system for seawater desalination.}, } @article {pmid38168339, year = {2023}, author = {Momeni, SS and Cao, X and Xie, B and Rainey, K and Childers, NK and Wu, H}, title = {Intraspecies interactions of Streptococcus mutans impact biofilm architecture and virulence determinants in childhood dental caries.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.12.13.571561}, pmid = {38168339}, abstract = {UNLABELLED: Early childhood dental caries (ECC) is the most common chronic disease among children with a heavy disease burden among low socioeconomic populations. Streptococcus mutans is most frequently associated with initiation of ECC. Many studies report children with multiple S. mutans strains (i.e., genotypes) having greater odds of developing ECC, studies investigating intraspecies interactions in dental caries are lacking. In this study, the impact of intraspecies interactions on cariogenic and fitness traits of clinical S. mutans isolates are investigated using in-vitro and in-vivo approaches. Initially clinical S. mutans isolates of 10 children from a longitudinal epidemiological study were evaluated. S. mutans strains (G09 and G18, most prevalent) isolated from one child were used for subsequent analysis. Association analysis was used to determine if presence of multiple S. mutans genotypes within the first-year of colonization was associated with caries. Biofilm analysis was performed for single and mixed cultures to assess cariogenic traits, including biofilm biomass, intra-polysaccharide, pH, and glucan. Confocal Laser Scanning Microscopy (CLSM) and time-lapse imaging were used to evaluate spatial and temporal biofilm dynamics, respectively. A Drosophila model was used to assess colonization in-vivo . Mean biofilm pH was significantly lower in co-cultured biofilms as compared with monoculture biofilms. Doubling of S. mutans in-vitro biofilms was observed by CLSM and in-vivo colonization in Drosophila for co-cultured S. mutans . Individual strains occupied specific domains in co-culture and G09 contributed most to increased co-culture biofilm thickness and colonization in Drosophila . Biofilm formation and acid production displayed distinct signatures in time-lapsed experiments.

IMPORTANCE: This study sheds light on the complex dynamics of a key contributor to early childhood dental caries (ECC) by exploring intraspecies interactions of different S. mutans strains and their impact on cariogenic traits. Utilizing clinical isolates from children with ECC, the research highlights significant differences in biofilm architecture and acid production in mixed versus single genotype cultures. The findings reveal that co-cultured S. mutans strains exhibit increased cell density and acidity, with individual strains occupying distinct domains. These insights, enhanced by use of time-lapsed Confocal Laser Scanning Microscopy and a Drosophila model, offer a deeper understanding of ECC pathogenesis and potential avenues for targeted interventions.}, } @article {pmid38167941, year = {2024}, author = {Dong, W and Xu, L and Chen, M and Jiang, T and Su, L and Ma, J and Chen, CP and Zhang, G}, title = {Co-, N-doped carbon dot nanozymes based on an untriggered ROS generation approach for anti-biofilm activities and in vivo anti-bacterial treatment.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb01794j}, pmid = {38167941}, issn = {2050-7518}, abstract = {Bacterial infections originating from food, water, and soil are widely recognized as significant global public health concerns. Biofilms are implicated in approximately two-thirds of bacterial infections. In recent times, nanomaterials have emerged as potential agents for combating biofilms and bacteria, with many of them being activated by light and H2O2 to generate reactive oxygen species (ROS). However, this energy-consuming and extrinsic substrate pattern poses many challenges for practical application. Consequently, there is a pressing need to develop methods for the untriggered generation of ROS to effectively address biofilm and bacterial infections. In this study, we investigated the oxidase-like activity of the Co,N-doped carbon dot (CoNCD) nanozyme, which facilitated the oxidation of ambient O2 to generate [1]O2 in the absence of light and H2O2 supplementation; this resulted in effective biofilm cleavage and enhanced bactericidal effects. CoNCDs could become a potential candidate for wound healing and treatment of acute peritonitis in vivo, which can be primarily attributed to the spontaneous production of ROS. This study presents a convenient ROS generator that does not necessitate any specific triggering conditions. The nanozyme properties of CoNCDs exhibit significant promise as a potential remedy for diseases, specifically as an anti-biofilm and anti-bacterial agent.}, } @article {pmid38167132, year = {2024}, author = {Özarslan, M and Avcioglu, NH and Bilgili Can, D and Çalışkan, A}, title = {Biofilm formation of C. albicans on occlusal device materials and antibiofilm effects of chitosan and eugenol.}, journal = {The Journal of prosthetic dentistry}, volume = {131}, number = {1}, pages = {144.e1-144.e9}, doi = {10.1016/j.prosdent.2023.10.005}, pmid = {38167132}, issn = {1097-6841}, abstract = {STATEMENT OF PROBLEM: Microbial adhesion on occlusal devices may lead to oral diseases such as candidiasis. Whether chitosan and eugenol provide antibiofilm effects is unclear.

PURPOSE: The purpose of this in vitro study was to evaluate the biofilm formation of C. albicans strains on occlusal device materials and the antibiofilm effects of chitosan and eugenol against C. albicans on these surfaces.

MATERIAL AND METHODS: A total of 88 specimens (5×10×2 mm) were produced from occlusal device materials with 4 production techniques: vacuum-formed thermoplastic (Group V), head-press (Group H), computer-aided design and computer-aided manufacture (CAD-CAM) (Group C), and 3-dimensionally (3D) printed (Group D) (n=22). After various finishing procedures, the surface properties of the specimens were evaluated by using surface free energy (SFE), surface roughness (SR) measurements, and elemental and topographic analysis. Biofilm formation of C. albicans strain and the antibiofilm effects of chitosan and eugenol against biofilm formation on these surfaces were also examined with a crystal violet assay. The distribution's normality was statistically analyzed with the Kolmogorov-Smirnov test. One-way and two-way analysis of variance with post hoc Tukey tests were used for statistical evaluations (α=.05).

RESULTS: Surface roughness values in Groups D and H were significantly higher than in other groups (P<.05). While the highest surface free energy values (except γp) were in Group V, Group C had the highest γp. The lowest biofilm value appeared in Group H. Chitosan exhibited an antibiofilm effect in all groups except Group H, while eugenol was effective in all groups.

CONCLUSIONS: The production method affected the susceptibility of occlusal device materials to the adhesion of C. albicans. Eugenol was an effective antibiofilm agent for device materials.}, } @article {pmid38163930, year = {2024}, author = {Meng, D and Li, Y}, title = {Assessing the Settling Velocity of Biofilm-Encrusted Microplastics: Accounting for Biofilms as an Equivalent to Surface Roughness.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c07147}, pmid = {38163930}, issn = {1520-5851}, abstract = {While it is well established that a biofilm contributes to the sinking of plastics, the underlying mechanisms of how it influences the vertical transport of plastics have not been well explained. In this context, our study dives into the intricate effects of biofouling on the settling velocity (Ws) of microplastics (MPs) within the fluid. We adopt the perspective that the biofilm is a form of surface roughness impacting the drag coefficient (Cd) and vertical settling of MPs. By advancing the biofouling process model, we simulate the temporal variations of density and biofilm thickness of biofouled floating MPs, accounting for realistic parameters and assuming a layer-by-layer growth of biofilm on plastisphere surfaces. MPs of polyethylene (PE) exhibit a quicker initiation of descent compared to their polypropylene (PP) counterparts. Furthermore, leveraging computational fluid dynamics (CFD) simulation, the method to predict the Cd of spherical MPs with surface roughness is established. By treating the thickness of the biofilm as roughness height, an explicit method to predict the Ws of biofouled MPs is derived. The settling experiments for biofouled MPs conducted not only support the combination of the biofouling model and the explicit method to predict the Ws of biofouled MPs but also enhance the prediction accuracy by introducing a ratio parameter Co to better relate the equivalent surface roughness height (k) to the biofilm thickness (σ), i.e., k = Co·σ, where the recommended value of Co for spherical PP and PE MPs is between 0.5 to 0.8. This study, thus, provides new insights into the dynamics of biofouled MPs in hydraulic ecosystems.}, } @article {pmid38163543, year = {2023}, author = {Feng, B and Chen, J and Wang, C and You, G and Lin, J and Gao, H and Han, S and Ma, J}, title = {Ofloxacin weakened treatment performance of rural domestic sewage in an aerobic biofilm system by affecting biofilm resistance, bacterial community, and functional genes.}, journal = {Environmental research}, volume = {}, number = {}, pages = {118036}, doi = {10.1016/j.envres.2023.118036}, pmid = {38163543}, issn = {1096-0953}, abstract = {Ofloxacin (OFL) is a typical fluoroquinolone antibiotic widely detected in rural domestic sewage, however, its effects on the performance of aerobic biofilm systems during sewage treatment process remain poorly understood. We carried out an aerobic biofilm experiment to explore how the OFL with different concentrations affects the pollutant removal efficiency of rural domestic sewage. Results demonstrated that the OFL negatively affected pollutant removal in aerobic biofilm systems. High OFL levels resulted in a decrease in removal efficiency: 9.33% for chemical oxygen demand (COD), 18.57% for ammonium (NH4[+]-N), and 8.49% for total phosphorus (TP) after 35 days. The findings related to the chemical and biological properties of the biofilm revealed that the OFL exposure triggered oxidative stress and SOS responses, decreased the live cell number and extracellular polymeric substance content of biofilm, and altered bacterial community composition. More specifically, the relative abundance of key genera linked to COD (e.g., Rhodobacter), NH4[+]-N (e.g., Nitrosomonas), and TP (e.g., Dechlorimonas) removal was decreased. Such the OFL-induced decrease of these genera might result in the down-regulation of carbon degradation (amyA), ammonia oxidation (hao), and phosphorus adsorption (ppx) functional genes. The conventional pollutants (COD, NH4[+]-N, and TP) removal was directly affected by biofilm resistance, functional genes, and bacterial community under OFL exposure, and the bacterial community played a more dominant role based on partial least-squares path model analysis. These findings will provide valuable insights into understanding how antibiotics impact the performance of aerobic biofilm systems during rural domestic sewage treatment.}, } @article {pmid38163167, year = {2024}, author = {Barnes, J and Balestra, B and Knee, KL and Frederick, JA and Landaverde, N and Meiller, J}, title = {Freshwater algal biofilm assemblages are more effective than invertebrate assemblages at aggregating microplastics.}, journal = {Heliyon}, volume = {10}, number = {1}, pages = {e23239}, pmid = {38163167}, issn = {2405-8440}, abstract = {Microplastics, plastic particles less than 5 mm in length, are a ubiquitous pollutant in the environment, but research on freshwater microplastic contamination is lacking. A possible fate of microplastics in freshwater environments is to become entangled or aggregated in biofilms, which are matrices of algae, bacteria, and micro invertebrates that grow on underwater surfaces, following a progression of settling algae, periphyton, and finally invertebrate colonization. This in-situ study at the Oasis Marina at National Harbor in Oxon Hill, Maryland, examined how the taxonomic assemblages of freshwater biofilms in the Potomac River are associated with the number of microplastics aggregated within them. Aluminum discs, acting as artificial substrate for biofilm growth, were deployed at the water's surface and at 2 m depth to survey biofilm assemblage and were sampled monthly from October 2021-October 2022. Microplastic abundances in the water column were measured every 2 weeks over the same period. Spatial and temporal trends in trapped and suspended microplastics, water quality parameters (temperature, dissolved oxygen, pH, salinity, conductivity, turbidity, ammonia, nitrate, and phosphate), and biofilm assemblages were measured and compared to explore factors affecting the abundance of microplastics and their partitioning between the water column and biofilms. Water quality had no measurable impact on microplastic abundance in the water column at either depth, but temperature was negatively correlated to microplastic abundance in biofilms. As the weather warmed and biofilms progressed to invertebrate settling, they tended to contain fewer microplastics. This may have occurred because less biologically rich biofilms, primarily composed of unicellular algal colonies, provide a favorable surface for microplastic deposition. Understanding seasonal changes in biofilm assemblage and microplastic abundance may help track the fate of microplastics in freshwater systems, particularly in their interactions with lower trophic organisms.}, } @article {pmid38161327, year = {2023}, author = {Verran, J and Wood, J and Redfern, J and Moravej, H and Radclyffe-Thomas, N}, title = {Hands On Biofilm! A multidisciplinary public engagement event using kombucha tea pellicle as an accessible example of biofilm.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100169}, doi = {10.1016/j.bioflm.2023.100169}, pmid = {38161327}, issn = {2590-2075}, abstract = {Public engagement with science has become increasingly important for the scientific community. There are many documented public engagement events that focus on aspects of microbiology, but relatively few utilise biofilms as a topic, despite their importance. Kombucha tea pellicles are easy to grow biofilms, facilitating their use within the public domain as examples of these complex communities. The aim of this work was to deliver a public engagement event that introduced visitors to general concepts about biofilm, and applications around sustainability, using kombucha. The event encouraged visitors to: build a biofilm using model clay; inoculate kombucha tea cultures using different incubation conditions, as part of a citizen science experiment to assess impact on pellicle biofilm yield; create garments and drapes on mini-mannequins using dried kombucha pellicle fabric, and demonstrate the range and importance of fermented foods (including kombucha tea), and 'good bacteria'. Quantitative and qualitative indicators of engagement were built into the activities. More than 1200 visitors, mainly in family groups, visited the event over a 4-h period. Knowledge of biofilms was low at the beginning of the event. Participation in all activities was high. Indicators of quantitative engagement were impressive, but it was difficult to obtain qualitative evidence other than observations from the delivery team (nineteen members) because of the intensity of the event and volume of visitors. The event was clearly successful in terms of fulfilment of aims, audience engagement and enthusiasm: the embedded evaluations helped to evidence the impact and reach of the event, enabling confidence in dissemination of good practice in the enhancement of public understanding of the importance of biofilm in general, and kombucha in particular.}, } @article {pmid38160987, year = {2023}, author = {Tian, D and Qiao, Y and Peng, Q and Xu, X and Shi, B}, title = {Anti-biofilm mechanism of a synthetical low molecular weight poly-d-mannose on Salmonella Typhimurium.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106515}, doi = {10.1016/j.micpath.2023.106515}, pmid = {38160987}, issn = {1096-1208}, abstract = {In this study, a low molecular weight poly-d-mannose (LMWM) was separated from a mixed polysaccharide synthesized previously. Monosaccharide composition, Fourier-Transform infrared spectroscopy (FT-IR), periodate oxidation and smith degradation were determined. After safety evaluation, the inhibition of LMWM on the different biofilm formation stages of Salmonella enterica serovar Typhimurium (S. Typhimurium) was tested in vitro. Furthermore, the effect of LMWM on the adhesion of S. Typhimurium to Caco-2 cells and cell surface hydrophobicity (CSH) were observed. Results indicated that LMWM was a homopolysaccharide without cytotoxicity and hemolysis, containing both α-mannose and β-mannose. It showed obvious anti-biofilm activity on S. Typhimurium and mainly activated on the initial adhesion and formation stage, even better than the commercial S. cerevisiae mannan (CM). LMWM inhibited the adhesion of S. Typhimurium on Caco-2 cells with the inhibition rate of 61.04 % at 2 mg/ml. Meanwhile, LMWM decreased the hydrophobicity of S. Typhimurium cell surface. In conclusion, the inhibitory effect on S. Typhimurium biofilm was not caused by bacteriostatic or bactericidal activity of LMWM. The specific anti-adhesion and the decrease of bacterial CSH by LMWM may closely relate to anti-biofilm mechanism. This study provides some supports for the application of LMWM as antibiotics alternative on S. Typhimurium in the future.}, } @article {pmid38159749, year = {2023}, author = {Zhang, Y and Wang, JX and Liu, Y and Zhang, JT and Wang, JH and Chi, ZY}, title = {Effects of environmental microplastic exposure on Chlorella sp. biofilm characteristics and its interaction with nitric oxide signaling.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {169659}, doi = {10.1016/j.scitotenv.2023.169659}, pmid = {38159749}, issn = {1879-1026}, abstract = {Microalgal biofilm is promising in simultaneous pollutants removal, CO2 fixation, and biomass resource transformation when wastewater is used as culturing medium. Nitric oxide (NO) often accumulates in microalgal cells under wastewater treatment relevant abiotic stresses such as nitrogen deficiency, heavy metals, and antibiotics. However, the influence of emerging contaminants such as microplastics (MPs) on microalgal intracellular NO is still unknown. Moreover, the investigated MPs concentrations among existing studies were mostly several magnitudes higher than in real wastewaters, which could offer limited guidance for the effects of MPs on microalgae at environment-relevant concentrations. Therefore, this study investigated three commonly observed MPs in wastewater at environment-relevant concentrations (10-10,000 μg/L) and explored their impacts on attached Chlorella sp. growth characteristics, nutrients removal, and anti-oxidative responses (including intracellular NO content). The nitrogen source NO3[-]-N at 49 mg/L being 20 % of the nitrogen strength in classic BG-11 medium was selected for MPs exposure experiments because of least intracellular NO accumulation, so that disturbance of intracellular NO by nitrogen availability could be avoided. Under such condition, 10 μg/L polyethylene (PE) MPs displayed most significant microalgal growth inhibition comparing with polyvinyl chloride (PVC) and polyamide (PA) MPs, showing extraordinarily low chlorophyll a/b ratios, and highest superoxide dismutase (SOD) activity and intracellular NO content after 12 days of MPs exposure. PVC MPs exposed cultures displayed highest malonaldehyde (MDA) content because of the toxic characteristics of organochlorines, and most significant correlations of intracellular NO content with conventional anti-oxidative parameters of SOD, CAT (catalase), and MDA. MPs accelerated phosphorus removal, and the type rather than concentration of MPs displayed higher influences, following the trend of PE > PA > PVC. This study expanded the knowledge of microalgal biofilm under environment-relevant concentrations of MPs, and innovatively discovered the significance of intracellular NO as a more sensitive indicator than conventional anti-oxidative parameters under MPs exposure.}, } @article {pmid38159586, year = {2023}, author = {Moradi Alvand, Z and Parseghian, L and Aliahmadi, A and Rahimi, M and Rafati, H}, title = {Nanoencapsulated Thymus daenensis and Mentha piperita essential oil for bacterial and biofilm eradication using microfluidic technology.}, journal = {International journal of pharmaceutics}, volume = {}, number = {}, pages = {123751}, doi = {10.1016/j.ijpharm.2023.123751}, pmid = {38159586}, issn = {1873-3476}, abstract = {The use of essential oil (EO) nanoemulsions is expanding to meet customer demand for all-natural antibacterial agents. Thymus daenensis (T) and Mentha piperita (M) EOs were employed to make nanoemulsions (TEO and MEO NE), using Tween 80/Span 80 as surfactant/cosurfactant and a high-speed homogenizer. The TEO and MEO NEs were then characterized in terms of particle size (121, 113 nm), surface charge (-11.2 and -12.6 mV), morphology, and stability over time. Then, the antibacterial activity of EOs and their nanoformulations against Escherichia coli (E. coli) were evaluated based on various residence times, and concentrations on a microfluidic chip. The release of cytoplasmic constituents was used to compare the antibacterial activity of bulk EOs and nanoformulations. After completing MIC, MBC, and time-killing assays, the inhibitory effect of nanoformulations on E. coli biofilm formation was examined. Remarkable intensification was observed by employing a microfluidic chip owing to high-contact surface area provision between nanoemulsions and bacteria. Once compared to the conventional method for 3 h operation, the bacterial activity was nearly completely inhibited in a 24-min residence time using nanoemulsions. After 6 minutes of treatment, the cell membrane began to rupture, indicating that nanoemulsions could improve the antibacterial activity of bulk essential oils.}, } @article {pmid38158668, year = {2023}, author = {Salaie, RN}, title = {Comparison between mastic gum resin extract and chlorhexidine mouthwash in the prevention of biofilm formation on titanium dental implants.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {13}, pages = {189-195}, doi = {10.14715/cmb/2023.69.13.29}, pmid = {38158668}, issn = {1165-158X}, abstract = {The biofilm formation around dental implant abutment is considered the main cause of peri-implant infection. The use of antimicrobial mouthwash might potentially reduce biofilm formation and subsequent infection. This study aimed to evaluate the antibiofilm properties of mastic gum resin extract (MGRE) against S. Mutans biofilm on the surface of titanium dental implant discs. This study used grade five (medical grade) titanium dental implant discs measuring 15 mm in diameter. The substances in the MGRE were analyzed by gas chromatography mass spectrometry (GC-MS) which found 12 detectable chemicals in MGRE. In this study, S. mutans was collected around the healing abutment of a recently placed dental implant and then cultured on titanium discs (in vitro). After bacterial growth on the titanium specimens for 24 hours, they were subjected to either chlorhexidine gluconate (CHX), (n = 6) or MGRE (n = 6). The antibacterial activity tests showed that both CHX and MGRE significantly inhibited bacterial growth compared to the negative control, the lactate production and turbidity measurements were significantly lower in MGRE and CHX compared to the control (p ≤ 0.05). Regarding the antibiofilm activity, both treatments showed significantly less turbidity in their biofilm compared to the control. Moreover, scanning electron microscopy (SEM) images showed that there were very limited adherence cells on the titanium implant discs in treatment groups, while there were confluent and attached bacterial cells in the control. The MGRE showed an antimicrobial property against S. mutans indicating that it has a potential for clinical use as a mouthwash.}, } @article {pmid38158310, year = {2023}, author = {Jessel, K and Chapman, MR}, title = {Microbial warfare: B. subtilis antagonizes E. coli biofilm formation.}, journal = {Trends in microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tim.2023.12.006}, pmid = {38158310}, issn = {1878-4380}, abstract = {Biofilm formation helps bacteria to survive environmental challenges. Biofilm development often involves multiple genetic pathways that can be regulated by external signals. Diego Serra and his team (Cordisco et al.) explore how Bacillus subtilis can antagonize Escherichia coli macrocolony biofilm formation via the metabolite bacillaene.}, } @article {pmid38158064, year = {2023}, author = {Karami-Eshkaftaki, Z and Saei-Dehkordi, S and Albadi, J and Moradi, M and Saei-Dehkordi, SS}, title = {Coated composite paper with nano-chitosan/cinnamon essential oil-nanoemulsion containing grafted CNC@ZnO nanohybrid; synthesis, characterization and inhibitory activity on Escherichia coli biofilm developed on grey zucchini.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128981}, doi = {10.1016/j.ijbiomac.2023.128981}, pmid = {38158064}, issn = {1879-0003}, abstract = {This investigation aims to highlight the applicability of a potent eco-friendly developed composite film to combat the Escherichia coli biofilm formed in a model food system. ZnO nanoparticles (NPs) synthesized using green methods were anchored on the surface of cellulose nanocrystals (CNCs). Subsequently, nano-chitosan (NCh) solutions were used to disperse the synthesized nanoparticles and cinnamon essential oil (CEO). These solutions, containing various concentrations of CNC@ZnO NPs and CEO, were sequentially coated onto cellulosic papers to inhibit Escherichia coli biofilms on grey zucchini slices. Six films were developed, and Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, biodegradation, and mechanical properties were assessed. The film containing 5 % nano-emulsified CEO + 3 % dispersed CNC@ZnO nano-hybrid in an NCh solution was selected for further testing since it exhibited the largest zone of inhibition (34.32 mm) against E. coli and the highest anti-biofilm activity on biofilms developed on glass surfaces. The efficacy of the film against biofilms on zucchini surfaces was temperature-dependent. During 60 h, the selected film resulted in log reductions of approximately 4.5 logs, 2.85 logs, and 1.57 logs at 10 °C, 25 °C, and 37 °C, respectively. Applying the selected film onto zucchini surfaces containing biofilm structures leads to the disappearance of the distinctive three-dimensional biofilm framework. This innovative anti-biofilm film offers considerable potential in combatting biofilm issues on food surfaces. The film also preserved the sensory quality of zucchini evaluated for up to 60 days.}, } @article {pmid38157766, year = {2023}, author = {Jeong, GJ and Rather, MA and Khan, F and Tabassum, N and Mandal, M and Kim, YM}, title = {pH-responsive polymeric nanomaterials for the treatment of oral biofilm infections.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {234}, number = {}, pages = {113727}, doi = {10.1016/j.colsurfb.2023.113727}, pmid = {38157766}, issn = {1873-4367}, abstract = {Bacterial and fungal pathogens forming oral biofilms present significant public health challenges due to the failure of antimicrobial drugs. The ability of biofilms to lower pH levels results in dental plaque, leading to gingivitis and cavities. Nanoparticles (NPs) have attracted considerable interest for drug delivery and, thus, as a solution to biofilm-related microbial infections. A novel strategy in this regard involves using pH-responsive polymeric NPs within the acidic microenvironment of oral biofilms. The acidity of the oral biofilm microenvironment is governed by carbohydrate metabolism, accumulation of lactic acid, and extracellular DNA of extracellular polymeric substances by oral biofilm-forming microbial pathogens. This acidity also provides an opportunity to enhance antibacterial activity against biofilm cells using pH-responsive drug delivery approaches. Thus, various polymeric NPs loaded with poorly soluble drugs and responsive to the acidic pH of oral biofilms have been developed. This review focuses on various forms of such polymeric NPs loaded with drugs. The fundamental mechanisms of action of pH-responsive polymeric NPs, their cytological toxicity, and in vivo efficacy testing are thoroughly discussed.}, } @article {pmid38156318, year = {2023}, author = {Cleaver, L and Garnett, JA}, title = {How to study biofilms: technological advancements in clinical biofilm research.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1335389}, pmid = {38156318}, issn = {2235-2988}, mesh = {Humans ; Animals ; *Biofilms ; *Bacteria ; Fungi ; Extracellular Matrix ; }, abstract = {Biofilm formation is an important survival strategy commonly used by bacteria and fungi, which are embedded in a protective extracellular matrix of organic polymers. They are ubiquitous in nature, including humans and other animals, and they can be surface- and non-surface-associated, making them capable of growing in and on many different parts of the body. Biofilms are also complex, forming polymicrobial communities that are difficult to eradicate due to their unique growth dynamics, and clinical infections associated with biofilms are a huge burden in the healthcare setting, as they are often difficult to diagnose and to treat. Our understanding of biofilm formation and development is a fast-paced and important research focus. This review aims to describe the advancements in clinical biofilm research, including both in vitro and in vivo biofilm models, imaging techniques and techniques to analyse the biological functions of the biofilm.}, } @article {pmid38156300, year = {2023}, author = {Ganjo, AR and Ali, FA and Aka, ST and Hussen, BM and Smail, SB}, title = {Diversity of biofilm-specific antimicrobial resistance genes in Pseudomonas aeruginosa recovered from various clinical isolates.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {6}, pages = {742-749}, pmid = {38156300}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The resistance of Pseudomonas aeruginosa to antibiotics offers a significant challenge in the treatment of patients. This study aimed to investigate the antimicrobial resistance profile, biofilm-specific antimicrobial resistance genes, and genetic diversity of P. aeruginosa recovered from clinical samples.

MATERIALS AND METHODS: Totally 47 non-duplicate isolates of P. aeruginosa were recovered from various clinical samples. toxA, algD, ndvB, and tssC1 genes were detected in biofilm-producing isolates. The DNA sequences of the toxA and tssC1 genes were analyzed, by creating phylogenetic trees.

RESULTS: The findings revealed that 30 (63.8%) of the isolates tested positive for Extended spectrum β-lactamase (ESBL), whereas 31 (65.9%) tested positive for Metallo-β-lactamase (MBL) and all of the isolates presented the toxA genes, and 19.1%,17%, 6.3% presented by algD, ndvB and tssC1 genes. Besides, the phylogenetic trees of the toxA and tssC1 gene isolates suggested a genotype that was closely aligned with others. Gene sequencing similarity revealed 99% identity with other isolates deposited in GenBank.

CONCLUSION: The occurrence of toxA was most prevalent. One isolate was recorded as a novel isolate in the global gene bank as a locally isolated strain from the city of Erbil that has never been identified in global isolates due to genetic variation.}, } @article {pmid38155383, year = {2023}, author = {Navarathinam, SD and Neoh, HM and Tan, TL and Wahab, AA and Mohd Nizam Tzar, MN and Ding, CH}, title = {Antifungal susceptibility profile and biofilm-producing capability of Candida tropicalis isolates in a tertiary medical centre.}, journal = {The Malaysian journal of pathology}, volume = {45}, number = {3}, pages = {417-424}, pmid = {38155383}, issn = {0126-8635}, abstract = {BACKGROUND: Candida tropicalis is a globally distributed yeast that has been popping up in the medical literature lately, albeit for unenviable reasons. C. tropicalis is associated with substantial morbidity, mortality as well as drug resistance. The aims of this study were to ascertain the antifungal susceptibility profile and the biofilm-producing capability of this notorious yeast in our centre.

METHODS: C. tropicalis isolates from sterile specimens were collected over a 12-month period. Conclusive identification was achieved biochemically with the ID 32 C kit. Susceptibility to nine antifungal agents was carried out using the colourimetric broth microdilution kit Sensititre YeastOne YO10. Biofilm-producing capability was evaluated by quantifying biomass formation spectrophotometrically following staining with crystal violet.

RESULTS: Twenty-four non-repetitive isolates of C. tropicalis were collected. The resistance rates to the triazole agents were 29.2% for fluconazole, 16.7% for itraconazole, 20.8% for voriconazole and 8.3% for posaconazole-the pan-azole resistance rate was identical to that of posaconazole. No resistance was recorded for amphotericin B, flucysosine or any of the echinocandins tested. A total of 16/24 (66.7%) isolates were categorized as high biomass producers and 8/24 (33.3%) were moderate biomass producers. None of our isolates were low biomass producers.

CONCLUSION: The C. tropicalis isolates from our centre were resistant only to triazole agents, with the highest resistance rate being recorded for fluconazole and the lowest for posaconazole. While this is not by itself alarming, the fact that our isolates were prolific biofilm producers means that even azole-susceptible isolates can be paradoxically refractory to antifungal therapy.}, } @article {pmid38154803, year = {2023}, author = {Tang, Y and Tao, C and Zhang, Z and Liu, S and Dong, F and Zhang, D and Zhang, J and Wang, X}, title = {The porous structure induced heterogeneous and localized failure of the biofilm in microfluidic channels.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {88}, number = {12}, pages = {3181-3193}, doi = {10.2166/wst.2023.384}, pmid = {38154803}, issn = {0273-1223}, abstract = {Understanding the mechanism of biofilm distribution and detachment is very important to effectively improve water treatment and prevent blockage in porous media. The existing research is more related to the local biofilm evolving around one or few microposts and the lack of the integral biofilm evolution in a micropost array for a longer growth period. This study combines microfluidic experiments and mathematical simulations to study the distribution and detachment of biofilm in porous media. Microfluidic chips with an array of microposts with different sizes are designed to simulate the physical pore structure of soil. The research shows that the initial formation and distribution of biofilm are influenced by bacterial transport velocity gradients within the pore space. Bacteria prefer to aggregate areas with smaller microposts, leading to the development of biofilm in those regions. Consequently, impermeable blockage structures form in this area. By analyzing experimental images of biofilm structures at the later stages, as well as coupling fluid flow and porous medium, and the finite element simulation, we find that the biofilm detachment is correlated with the morphology and permeability (kb) (from 10[-15] to 10[-9] m[2]) of the biofilm. The simulations show that there are two modes of biofilm detachment, such as internal detachment and external erosion.}, } @article {pmid38154453, year = {2023}, author = {Rikvold, PD and Hansen Skov, LB and Louise Meyer, R and Rose Jorgensen, M and Tiwari, MK and Schlafer, S}, title = {The effect of enzymatic treatment with mutanase, beta-glucanase and DNase on a saliva-derived biofilm model.}, journal = {Caries research}, volume = {}, number = {}, pages = {}, doi = {10.1159/000535980}, pmid = {38154453}, issn = {1421-976X}, abstract = {INTRODUCTION: The dental biofilm matrix is an important determinant of virulence for caries development and comprises a variety of extracellular polymeric substances that contribute to biofilm stability. Enzymes that break down matrix components may be a promising approach to caries control, and in light of the compositional complexity of the dental biofilm matrix, treatment with multiple enzymes may enhance the reduction of biofilm formation compared to single enzyme therapy. The present study investigated the effect of the three matrix-degrading enzymes mutanase, beta-glucanase and DNase, applied separately or in combinations, on biofilm prevention and removal in a saliva-derived in vitro-grown model.

METHODS: Biofilms were treated during growth to assess biofilm prevention or after 24 h of growth to assess biofilm removal by the enzymes. Biofilms were quantified by crystal violet staining and impedance-based real-time cell analysis, and the biofilm structure was visualized by confocal microscopy and staining of extracellular DNA (eDNA) and polysaccharides.

RESULTS: The in vitro model was dominated by Streptococcus spp., as determined by 16S rRNA gene amplicon sequencing. All tested enzymes and combinations had a significant effect on biofilm prevention, with reductions of >90% for mutanase and all combinations including mutanase. Combined application of DNase and beta-glucanase resulted in an additive effect (81.0%±1.3% SD vs. 36.9%±21.9% SD and 48.2%±14.9% SD). For biofilm removal, significant reductions of up to 73.2%±5.5% SD were achieved for combinations including mutanase, whereas treatment with DNase had no effect. Glucans, but not eDNA decreased in abundance upon treatment with all three enzymes.

CONCLUSION: Multi-enzyme treatment is a promising approach to dental biofilm control that needs to be validated in more diverse biofilms.}, } @article {pmid38153717, year = {2023}, author = {Suresh, K and Pillai, D and Soman, M and Sreenivas, A and Paul, R}, title = {Isolation and identification of antimicrobial susceptibility, biofilm formation, efflux pump activity, and virulence determinants in multi-drug resistant Pseudomonas aeruginosa isolated from freshwater fishes.}, journal = {Journal of water and health}, volume = {21}, number = {12}, pages = {1858-1870}, doi = {10.2166/wh.2023.206}, pmid = {38153717}, issn = {1477-8920}, abstract = {The present study was undertaken to evaluate the prevalence, underlying resistance mechanism, and virulence involved in Pseudomonas aeruginosa (n = 35) isolated from freshwater fishes in Andhra Pradesh, India. Antibiogram studies revealed that 68.5, 62.8, 37.1, 11.4, 8.5, 57.1, 54.2, and 48.5% of isolates had resistance to oxytetracycline, co-trimoxazole, doxycycline, enrofloxacin, ciprofloxacin, cefotaxime, ceftazidime, and ampicillin, respectively. The resistant isolates harboured the tetA (85.7%), tetD (71.4%), tetM (91.4%), sul1 (80%), blaCTX-M (57.1%), blaTEM (42.8%), and blaSHV (48.5%) genes. In total, 50% of the isolates were altered as multi-drug resistant, and the multiple antibiotic resistance index was calculated as 0.4. Furthermore, 37.3, 48.5, and 14.2% of isolates were categorized as strong, moderate, and weak biofilm formers, possessing pslA (91.5%) and pslD (88.6%) biofilm encoding genes. In total, 82.8% of the isolates exhibited efflux pump activity and harboured the mexA (74.2%), mexB (77.1%), and oprM (37.1%) genes. Virulent genes oprL, toxA, exoS, and phzM were detected in 68.5, 68.5, 100, and 17.1% of isolates, respectively. The data suggested that P. aeruginosa harbours multiple resistance mechanisms and virulence factors that may contribute to antibiotic resistance and pathogenicity, and their distribution in fish culture facilities highlights the public health hazards of the food chain.}, } @article {pmid38153409, year = {2023}, author = {Viering, BL and Balogh, H and Cox, CF and Kirpekar, OK and Akers, AL and Federico, VA and Valenzano, GZ and Stempel, R and Pickett, HL and Lundin, PM and Blackledge, MS and Miller, HB}, title = {Loratadine Combats Methicillin-Resistant Staphylococcus aureus by Modulating Virulence, Antibiotic Resistance, and Biofilm Genes.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00616}, pmid = {38153409}, issn = {2373-8227}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has evolved to become resistant to multiple classes of antibiotics. New antibiotics are costly to develop and deploy, and they have a limited effective lifespan. Antibiotic adjuvants are molecules that potentiate existing antibiotics through nontoxic mechanisms. We previously reported that loratadine, the active ingredient in Claritin, potentiates multiple cell-wall active antibiotics in vitro and disrupts biofilm formation through a hypothesized inhibition of the master regulatory kinase Stk1. Loratadine and oxacillin combined repressed the expression of key antibiotic resistance genes in the bla and mec operons. We hypothesized that additional genes involved in antibiotic resistance, biofilm formation, and other cellular pathways would be modulated when looking transcriptome-wide. To test this, we used RNA-seq to quantify transcript levels and found significant effects in gene expression, including genes controlling virulence, antibiotic resistance, metabolism, transcription (core RNA polymerase subunits and sigma factors), and translation (a plethora of genes encoding ribosomal proteins and elongation factor Tu). We further demonstrated the impacts of these transcriptional effects by investigating loratadine treatment on intracellular ATP levels, persister formation, and biofilm formation and morphology. Loratadine minimized biofilm formation in vitro and enhanced the survival of infected Caenorhabditis elegans. These pleiotropic effects and their demonstrated outcomes on MRSA virulence and survival phenotypes position loratadine as an attractive anti-infective against MRSA.}, } @article {pmid38152946, year = {2023}, author = {Hage, W and Sarkis, DK and Kallasy, M and Sfeir, G and Mallah, M and Hachem, RE and Khalil, I and Zogheib, C}, title = {Antimicrobial Activity of Five Calcium Silicate Based Root Canal Sealers against a Multispecies Engineered Biofilm: An In Vitro Study.}, journal = {The journal of contemporary dental practice}, volume = {24}, number = {9}, pages = {707-714}, doi = {10.5005/jp-journals-10024-3556}, pmid = {38152946}, issn = {1526-3711}, abstract = {AIM: The present study's objective was to compare the impact of CerasealR, total fill BC SealerR, Bio-C SealerR, AH Plus BioceramicR, and K-BiocerR on the elimination of a multispecies' endodontic biofilm at 3, 7 and 14 days.

MATERIALS AND METHODS: A total of 20 freshly extracted, caries-free premolars were prepared for the study to create dentinal disks. For the multispecies biofilm formation, Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa, and Candida albicans were cultured and used to inoculate hydroxyapatite discs. After incubation, the biofilms were placed on blotting papers in petri dishes with an orthodontic bend. Different root canal sealers, including CeraSeal, total Fill BC Sealer, Bio-C Sealer, AH Plus Bioceramic, K-Biocer, and Sealite, were injected into the bend, facilitating contact with the biofilms. The samples were divided into seven groups, including a negative control. At specific intervals, 3, 7, and 14 days, 3 biofilm samples from each group were collected, diluted, and plated on Agar media for colony counting and analysis.

RESULTS: In all tested groups, the total bacterial count significantly decreased between day 3 and 14 (p < 0.05) with no statistically significant differences among the different sealers' groups at all-time points for the total bacterial count, E. faecalis count, and P. mirabilis count. However, Sealite demonstrated the most consistent effectiveness in reducing bacterial counts across multiple categories. The sealite group was capable of decreasing the C. albicans count significantly between day 3 and day 14 (p < 0.05) in comparison with the bioceramic groups.

CONCLUSION: All sealers had antibacterial activity against the multispecies biofilm between day 3 and day 14. The ascending order of sealers in terms of their effectiveness in killing bacteria, based on the provided results, is as follows: Sealite, Bio-C Sealer, AH Plus, CeraSeal, TotalFill, and K-Biocer. However, there were no statistically significant differences in the bacterial counts among the different sealer groups at any time point.

CLINICAL SIGNIFICANCE: The role of sealers in combating biofilm-associated infections highlights their potential clinical utility in preserving root canal health. Understanding the antimicrobial properties of these sealers is vital for informed decision-making in selecting the most effective materials for improved treatment outcomes and long-term success in endodontic procedures.}, } @article {pmid38147806, year = {2023}, author = {Cai, X and Yang, S and Peng, Y and Tan, K and Xu, P and Wu, Z and Kwan, KY and Jian, J}, title = {Regulation of PhoB on biofilm formation and hemolysin gene hlyA and ciaR of Streptococcus agalactiae.}, journal = {Veterinary microbiology}, volume = {289}, number = {}, pages = {109961}, doi = {10.1016/j.vetmic.2023.109961}, pmid = {38147806}, issn = {1873-2542}, abstract = {PhoB is a response regulator protein that plays a key role in the PhoBR two-component signal transduction system. In this study, we used transcriptome and proteomics techniques to evaluate the detect the gene network regulated by PhoB of Streptococcus agalactiae. The results showed that expression of biofilm formation and virulence-related genes were changed after phoB deficiency. Crystal violet and CLSM assay confirmed that the deletion of the phoB increased the thickness of S. agalactiae biofilm. The results of lacZ reporter and the bacterial one-hybridization method showed that PhoB could directly bind to the promoter regions of hemolysin A and ciaR genes but not to the promoter regions of cylE and hemolysin III. Through the construction of an 18-base pair deoxyribose nucleic acid (DNA) random fragment library and the bacterial one-hybridization system, it was found that the conservative sequence of PhoB binding was TTGGAGAA(G/T). Our research has uncovered the virulence potential of the PhoBR two-component system of S. agalactiae. The findings of this study provide the theoretical foundation for in-depth research on the pathogenic mechanism of S. agalactiae.}, } @article {pmid38147410, year = {2023}, author = {Yao, S and Tu, R and Jin, Y and Zhou, R and Wu, C and Qin, J}, title = {Improvement of the viability of Tetragenococcus halophilus under acidic stress by forming the biofilm cell structure based on RNA-Seq and iTRAQ analyse.}, journal = {Journal of the science of food and agriculture}, volume = {}, number = {}, pages = {}, doi = {10.1002/jsfa.13240}, pmid = {38147410}, issn = {1097-0010}, abstract = {BACKGROUND: Tetragenococcus halophilus is a halophilic lactic acid bacterium (LAB) isolated from soya sauce moromi. During the production of these fermented foods, acid stress is an inevitable environmental stress. In our previous study, T. halophilus could form biofilms and the cells in biofilms exhibited higher cell viability under multiple environmental stress including acid stress.

RESULTS: In this study, the effect of preformed T. halophilus biofilms on cell survival, cellular structure, intracellular environment, and the expression of genes and proteins under acid stress was investigated. The result showed that acid stress with pH 4.30 for 1.5 h reduced live T. halophilus cell count and caused cellular structure damage. However, T. halophilus biofilm cells exhibited greater cell survival under acid stress than the planktonic cells, and biofilm formation reduced the damage of acid stress to the cell membrane and cell wall. The biofilm cells maintained a higher level of H[+] -ATPase activity and intracellular ammonia concentration after acid stress. The RNA-Seq and iTRAQ technologies revealed that the genes and proteins associated with ATP production, the uptake of trehalose and N-acetylmuramic acid, the assembly of H[+] -ATPase, amino acid biosynthesis and metabolism, ammonia production, fatty acid biosynthesis, CoA biosynthesis, thiamine production, and acetoin biosynthesis might be responsible for the stronger acid tolerance of T. halophilus biofilm cells together.

CONCLUSION: These findings provided help for further understanding the mechanisms that allowed LAB biofilm cells to resist environmental stress. This article is protected by copyright. All rights reserved.}, } @article {pmid38146023, year = {2023}, author = {Rahmani, A and Parizadeh, L and Baud, M and Francois, Y and Bazire, A and Rodrigues, S and Fleury, Y and Cuny, H and Debosse, E and Cabon, J and Louboutin, L and Bellec, L and Danion, M and Morin, T}, title = {Correction to: Potential of Marine Strains of Pseudoalteromonas to Improve Resistance of Juvenile Sea Bass to Pathogens and Limit Biofilm Development.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12602-023-10206-y}, pmid = {38146023}, issn = {1867-1314}, } @article {pmid38144224, year = {2023}, author = {Wang, W and Zhong, Q and Cheng, K and Tan, L and Huang, X}, title = {Molecular Characteristics, Antimicrobial Susceptibility, Biofilm-Forming Ability of Clinically Invasive Staphylococcus aureus Isolates.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {7671-7681}, pmid = {38144224}, issn = {1178-6973}, abstract = {PURPOSE: This study aimed to investigate the molecular characteristics, antimicrobial resistance, and biofilm-forming ability of Staphylococcus aureus isolates from invasive infections.

METHODS: A total of 92 non-repetitive S. aureus isolates from invasive infections were analyzed by Multi-locus Sequence Typing (MLST), spa typing, and chromosomal cassette mec (SCCmec) typing. Antibiotic susceptibility testing was performed using the disk diffusion and agar dilution methods. Biofilm-forming ability was assessed using crystal violet assay. The presence and expression of biofilm-associated genes were examined using PCR and RT-qPCR.

RESULTS: Among the 55 Methicillin-resistant S. aureus (MRSA) and 41 Methicillin-sensitive S. aureus (MSSA) isolates, ST59 (43.6%) predominated in MRSA, while ST7 (39.0%) was most common in MSSA. As expected, MRSA exhibited higher antibiotic resistance rates compared to MSSA isolates. Biofilm formation assays revealed that the majority of isolates (88.5%) produced biofilms, with 26.0% classified as strong producers (OD570 ≥ 1.0) and 62.5% as weak producers (0.2 ≤ OD570<1.0). MSSA exhibited a higher biofilm-forming ability than MRSA (P < 0.01), with variations across clones. Notably, ST7 isolates displayed greater biofilm-forming ability than other sequence types (ST59, ST5, and ST239). RT-qPCR results revealed that ST7 isolates exhibited higher expression levels of icaA compared to other sequence types.

CONCLUSION: This study revealed significant molecular heterogeneity among invasive S. aureus isolates, with ST59 and ST7 as dominant clones. The strong biofilm-forming capacity of ST7 merits concern given its rising prevalence regionally. Continuous surveillance of emerging successful lineages is critical to help guide infection control strategies against invasive S. aureus infections.}, } @article {pmid38144076, year = {2023}, author = {Iyer, D and Laws, E and LaJeunesse, D}, title = {Escherichia coli Adhesion and Biofilm Formation on Polymeric Nanostructured Surfaces.}, journal = {ACS omega}, volume = {8}, number = {50}, pages = {47520-47529}, pmid = {38144076}, issn = {2470-1343}, abstract = {Biofilm formation is a multistep process that requires initial contact between a bacterial cell and a surface substrate. Recent work has shown that nanoscale topologies impact bacterial cell viability; however, less is understood about how nanoscale surface properties impact other aspects of bacterial behavior. In this study, we examine the adhesive, viability, morphology, and colonization behavior of the bacterium Escherichia coli on 21 plasma-etched polymeric surfaces. Although we predicted that specific nanoscale surface structures of the surface would control specific aspects of bacterial behavior, we observed no correlation between any bacterial response or surface structures/properties. Instead, it appears that the surface composition of the polymer plays the most significant role in controlling and determining a bacterial response to a substrate, although changes to a polymeric surface via plasma etching alter initial bacteria colonization and morphology.}, } @article {pmid38143147, year = {2023}, author = {Soni, JF and Ribeiro, VST and Cieslinski, J and de Andrade, AP and Dantas, LR and Pereira, BZ and de Almeida, BMRC and Suss, PH and Tuon, FF}, title = {Evaluation of silver nanoparticle-impregnated PMMA loaded with vancomycin or gentamicin against bacterial biofilm formation.}, journal = {Injury}, volume = {54 Suppl 6}, number = {}, pages = {110649}, doi = {10.1016/j.injury.2023.02.032}, pmid = {38143147}, issn = {1879-0267}, abstract = {INTRODUCTION: Bone cement containing vancomycin or gentamicin is a therapeutic strategy for combating orthopedic infections: however, the activity of these antibiotics is narrow. Silver nanoparticles (AgNPs) are nanocomponents with a wide spectrum, including multidrug-resistant bacteria. In the present study, we aimed to evaluate the effect of AgNP-loaded polymethylmethacrylate (PMMA) on biofilm formation by Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus epidermidis.

METHODS: The effect of AgNP-loaded PMMA with and without vancomycin or gentamicin on biofilm production was quantitatively analyzed. S. aureus, E. coli, P. aeruginosa, and S. epidermidis were included as biofilm-producing microorganisms in the in vitro model.

RESULTS: AgNP-loaded PMMA with antibiotics reduced the number of colony-forming units (CFUs; p<0.001). However, AgNP-loaded PMMA alone did not significantly reduce biofilm formation.

CONCLUSION: Our study demonstrated the potential of AgNP-loaded PMMA. Notably, we observed that AgNP-loaded PMMA containing vancomycin or gentamycin exhibited significantly superior efficacy, with satisfactory activity against most biofilm-forming microbial agents examined.}, } @article {pmid38142726, year = {2023}, author = {Liu, J and Han, Y and Dou, X and Liang, W}, title = {Effect of toluene on m-xylene removal in a biotrickling filter: Performance, biofilm characteristics, and microbial analysis.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117978}, doi = {10.1016/j.envres.2023.117978}, pmid = {38142726}, issn = {1096-0953}, abstract = {Hydrophobic volatile organic compounds (VOCs) pose a challenge to the removal efficiency in biotrickling filters (BTFs). The addition of relatively hydrophilic substances presents a promising approach for enhancing the elimination of hydrophobic VOCs. In this study, toluene was introduced into the BTF system alongside m-xylene, and their mixing ratios were changed to explore the interactions and mechanisms under different conditions. The result showed that the most pronounced synergistic interaction occurred when the mixing concentration ratio of m-xylene and toluene was 2:1. The removal efficiency (RE) of m-xylene increased from 88% to 97%, and the elimination capacity (EC) of m-xylene changed from 64 to 72 g m[-3] h[-1]. Under this condition, there was a notable increase in biomass, extracellular polymeric substance (EPS) content, and relative hydrophobicity. Microbial diversity was enhanced observably with Berkeleyces and Mycobacterium potentially playing a positive role in co-degradation. Meanwhile, microbial metabolic function prediction indicated a significant enhancement in metabolic functions. Therefore, the introduction of relatively hydrophilic VOCs represents an effective strategy for enhancing the removal of hydrophobic VOCs in the BTFs.}, } @article {pmid38142601, year = {2023}, author = {Li, C and Wang, JX and Wang, JH and Chi, ZY}, title = {Effects of staged multiple phytohormones application on capillary-driven attached Chlorella sp. biofilm.}, journal = {Journal of environmental management}, volume = {351}, number = {}, pages = {119886}, doi = {10.1016/j.jenvman.2023.119886}, pmid = {38142601}, issn = {1095-8630}, abstract = {Comparing with single phytohormone application, applying multiple phytohormones to microalgae-based wastewater treatment systems can offer more extensive growth-promoting and stress-protecting effects for microalgae, yet the advantage of stress-relieving salicylic acid (SA) under combined phytohormones application scenario has not been exploited. Employing the improved capillary-driven attached microalgae culturing device (CD-PBR) previously used for single phytohormone application, this study compared the effects of mixed and single phytohormone(s) addition under as low as 10[-7] M dosage. In order to make the best of SA for its stress-relieving property, postponed SA addition combined with applying other phytohormone(s) at the beginning of microalgae cultivation was also investigated. Combination of 10[-6] M 6-benzylaminopurine (6-BA) with 10[-7] M SA was sufficient for enhancing growth-promoting effects and anti-oxidative responses for attached Chlorella sp., while indole-3-acetic acid (IAA) addition was unnecessary. Combination of 6-BA addition at the beginning while postponed SA addition on Day 4 could further sustain such beneficial effects, while removing up to 99.7% total nitrogen (TN) and 97.9% total phosphorus (TP) from the bulk liquid. These results provided innovative strategies on mixed phytohormones addition for microalgae.}, } @article {pmid38142446, year = {2023}, author = {Liu, X and Li, J and Zhang, Z and He, Y and Wang, M and Zhao, Y and Lin, S and Liu, T and Liao, Y and Zhang, N and Yuan, K and Ling, Y and Liu, Z and Chen, X and Chen, Z and Chen, R and Wang, X and Gu, B}, title = {Acetylation of xenogeneic silencer H-NS regulates biofilm development through the nitrogen homeostasis regulator in Shewanella.}, journal = {Nucleic acids research}, volume = {}, number = {}, pages = {}, doi = {10.1093/nar/gkad1219}, pmid = {38142446}, issn = {1362-4962}, support = {32170160//National Science Foundation of China/ ; 2022FY100600//Science & Technology Fundamental Resources Investigation Program/ ; 2022B1111040002//Key Area Research and Development Program of Guangdong Province/ ; KY0120220256//Guandong Provincial People's Hospital/ ; }, abstract = {Adjusting intracellular metabolic pathways and adopting suitable live state such as biofilms, are crucial for bacteria to survive environmental changes. Although substantial progress has been made in understanding how the histone-like nucleoid-structuring (H-NS) protein modulates the expression of the genes involved in biofilm formation, the precise modification that the H-NS protein undergoes to alter its DNA binding activity is still largely uncharacterized. This study revealed that acetylation of H-NS at Lys19 inhibits biofilm development in Shewanella oneidensis MR-1 by downregulating the expression of glutamine synthetase, a critical enzyme in glutamine synthesis. We further found that nitrogen starvation, a likely condition in biofilm development, induces deacetylation of H-NS and the trimerization of nitrogen assimilation regulator GlnB. The acetylated H-NS strain exhibits significantly lower cellular glutamine concentration, emphasizing the requirement of H-NS deacetylation in Shewanella biofilm development. Moreover, we discovered in vivo that the activation of glutamine biosynthesis pathway and the concurrent suppression of the arginine synthesis pathway during both pellicle and attached biofilms development, further suggesting the importance of fine tune nitrogen assimilation by H-NS acetylation in Shewanella. In summary, posttranslational modification of H-NS endows Shewanella with the ability to respond to environmental needs by adjusting the intracellular metabolism pathways.}, } @article {pmid38141708, year = {2023}, author = {Maghrawy, HH and El Kareem, HA and Gomaa, OM}, title = {Enhanced exopolysaccharide production in gamma irradiated Bacillus subtilis: A biofilm-mediated strategy for ZnO nanoparticles removal.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128884}, doi = {10.1016/j.ijbiomac.2023.128884}, pmid = {38141708}, issn = {1879-0003}, abstract = {Biofilm-mediated strategy was studied for ZnO nanoparticle removal from aqueous media. Bacillus subtilis isolated from the soil rhizosphere was selected based on its high viscosity (133 Pa/s) of the cultivated culture and biofilm formation. The bacterium was exposed to gamma-irradiation to enhance EPS production along with its cultivation in EPS-producing media. The results show an increase in viscosity that reached 160 Pa/s at 2 kGy. EPS production increased from 4.45 to 7.95 mg/mL and the protein/carbohydrate ratio increased from 3 to 4.4 which reflects the stickiness of EPS. Thermal Gravimetric Analysis (TGA) showed 2 phase weight loss for gamma irradiated EPS and defined protein peaks when characterized using Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF). Native and gamma-irradiated Bacillus subtilis cells with their enhanced EPS were grown as a biofilm on sterile waste gauze fabric, Scanning Electron Microscopy (SEM) showed an increased biofilm attachment in gamma-irradiated samples. The latter was used for the removal of ZnO NP from aqueous media. Energy dispersive X-ray (EDX) mapping confirms that ZnO NPs were entrapped within the carbon and oxygen elements forming the biofilm with net intensities of 14.04, 1713, and 1190, respectively. The results confirm that biofilm-mediated strategy is effective in nanoparticles removal.}, } @article {pmid38141413, year = {2023}, author = {Liu, Y and Zhou, M and Zheng, N and Xu, H and Chen, X and Duan, Z and Lin, T and Zeng, R and Chen, Q and Li, M}, title = {Hsa_circ_0105040 promotes Cutbacterium acnes biofilm induced inflammation via sponge miR-146a in human keratinocyte.}, journal = {International immunopharmacology}, volume = {127}, number = {}, pages = {111424}, doi = {10.1016/j.intimp.2023.111424}, pmid = {38141413}, issn = {1878-1705}, abstract = {Acne is a chronic inflammatory skin disease, and the pathogenesis of acne induced by Cutibacterium acnes (C.acnes) is not well understood. Recently, circular RNAs (circRNAs) have attracted much attention because of its involvement in various diseases. However, the mechanisms by which circRNAs regulated acne have rarely been reported. We identified several differentially expressed circRNAs by sequencing patient-derived acne tissues. Among them, hsa_circ_0105040 was determined to be low expressed in acne tissues and localized in the cytoplasm of human primary keratinocytes. We established a C.acnes biofilms model of acne in vitro and showed that hsa_circ_0105040 promoted inflammation via MAPK and NF-κB pathway. Mechanistically, hsa_circ_0105040 could directly bind to miR-146a and inhibit the expression of miR-146a. Moreover, hsa_circ_0105040 promoted the expression of IRAK1 and TRAF6 by sponging miR-146a, thereby elevating the level of inflammation in acne. Collectively, our data suggested that hsa_circ_0105040- miR-146a -IRAK1/TRAF6 axis was involved in regulating the inflammatory response in acne, which provided a potential therapeutic target for acne and a novel insight into the pathogenesis of inflammatory acne.}, } @article {pmid38141140, year = {2023}, author = {Matar, MA and Darwish, SS and Salma, RS and Lotfy, WA}, title = {Correction to: Evaluation of the antibacterial activity of Enamelast[®] and Fluor defender[®] fluoride varnishes against Streptococcus mutans biofilm: an in vitro study in primary teeth.}, journal = {European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry}, volume = {}, number = {}, pages = {}, doi = {10.1007/s40368-023-00855-6}, pmid = {38141140}, issn = {1996-9805}, } @article {pmid38140696, year = {2023}, author = {Jdeed, G and Morozova, V and Kozlova, Y and Tikunov, A and Ushakova, T and Bardasheva, A and Manakhov, A and Mitina, M and Zhirakovskaya, E and Tikunova, N}, title = {StM171, a Stenotrophomonas maltophilia Bacteriophage That Affects Sensitivity to Antibiotics in Host Bacteria and Their Biofilm Formation.}, journal = {Viruses}, volume = {15}, number = {12}, pages = {}, pmid = {38140696}, issn = {1999-4915}, support = {075-15-2021-1085//Ministry of Science and Higher Education of the Russian Federation/ ; }, abstract = {Stenotrophomonas maltophilia mainly causes respiratory infections that are associated with a high mortality rate among immunocompromised patients. S. maltophilia exhibits a high level of antibiotic resistance and can form biofilms, which complicates the treatment of patients infected with this bacterium. Phages combined with antibiotics could be a promising treatment option. Currently, ~60 S. maltophilia phages are known, and their effects on biofilm formation and antibiotic sensitivity require further examination. Bacteriophage StM171, which was isolated from hospital wastewater, showed a medium host range, low burst size, and low lytic activity. StM171 has a 44kbp dsDNA genome that encodes 59 open-reading frames. A comparative genomic analysis indicated that StM171, along with the Stenotrophomonas phage Suso (MZ326866) and Xanthomonas phage HXX_Dennis (ON711490), are members of a new putative Nordvirus genus. S. maltophilia strains that developed resistance to StM171 (bacterial-insensitive mutants) showed a changed sensitivity to antibiotics compared to the originally susceptible strains. Some bacterial-insensitive mutants restored sensitivity to cephalosporin and penicillin-like antibiotics and became resistant to erythromycin. StM171 shows strain- and antibiotic-dependent effects on the biofilm formation of S. maltophilia strains.}, } @article {pmid38139199, year = {2023}, author = {Lei, Y and Rahman, K and Cao, X and Yang, B and Zhou, W and Reheman, A and Cai, L and Wang, Y and Tyagi, R and Wang, Z and Chen, X and Cao, G}, title = {Epinephrine Stimulates Mycobacterium tuberculosis Growth and Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {24}, number = {24}, pages = {}, doi = {10.3390/ijms242417370}, pmid = {38139199}, issn = {1422-0067}, support = {31602061, U21A20259, 31872470, 31902240//National Natural Science Foundation of China/ ; 2021YFD1800401//National Key Research and Development Program of China/ ; 2018M640718//China Postdoctoral Science Foundation/ ; }, abstract = {The human stress hormones catecholamines play a critical role in communication between human microbiota and their hosts and influence the outcomes of bacterial infections. However, it is unclear how M. tuberculosis senses and responds to certain types of human stress hormones. In this study, we screened several human catecholamine stress hormones (epinephrine, norepinephrine, and dopamine) for their effects on Mycobacterium growth. Our results showed that epinephrine significantly stimulated the growth of M. tuberculosis in the serum-based medium as well as macrophages. In silico analysis and molecular docking suggested that the extra-cytoplasmic domain of the MprB might be the putative adrenergic sensor. Furthermore, we showed that epinephrine significantly enhances M. tuberculosis biofilm formation, which has distinct texture composition, antibiotic resistance, and stress tolerance. Together, our data revealed the effect and mechanism of epinephrine on the growth and biofilm formation of M. tuberculosis, which contributes to the understanding of the environmental perception and antibiotic resistance of M. tuberculosis and provides important clues for the understanding of bacterial pathogenesis and the development of novel antibacterial therapeutics.}, } @article {pmid38139094, year = {2023}, author = {Moryl, M and Różalski, A and de Figueiredo, JAP and Palatyńska-Ulatowska, A}, title = {How Do Phages Disrupt the Structure of Enterococcus faecalis Biofilm?.}, journal = {International journal of molecular sciences}, volume = {24}, number = {24}, pages = {}, doi = {10.3390/ijms242417260}, pmid = {38139094}, issn = {1422-0067}, support = {2020/04/X/NZ6/00570//National Science Center/ ; 503/2-044-02/503-21-001-18//Medical University of Lodz, Poland/ ; }, abstract = {Biofilms are composed of multicellular communities of microbial cells and their self-secreted extracellular polymeric substances (EPS). The viruses named bacteriophages can infect and lyze bacterial cells, leading to efficient biofilm eradication. The aim of this study was to analyze how bacteriophages disrupt the biofilm structure by killing bacterial cells and/or by damaging extracellular polysaccharides, proteins, and DNA. The use of colorimetric and spectrofluorimetric methods and confocal laser scanning microscopy (CLSM) enabled a comprehensive assessment of phage activity against E. faecalis biofilms. The impact of the phages vB_Efa29212_2e and vB_Efa29212_3e was investigated. They were applied separately or in combination on 1-day and 7-day-old biofilms. Phages 2e effectively inhibited the growth of planktonic cells with a limited effect on the biofilm. They did not notably affect extracellular polysaccharides and proteins; however, they increased DNA levels. Phages 3e demonstrated a potent and dispersing impact on E. faecalis biofilms, despite being slightly less effective than bacteriophages 2e against planktonic cells. Phages 3e reduced the amount of extracellular polysaccharides and increased eDNA levels in both 1-day-old and 7-day-old biofilm cultures. Phage cocktails had a strong antimicrobial effect on both planktonic and biofilm-associated bacteria. A significant reduction in the levels of polysaccharides, proteins, and eDNA in 1-day-old biofilm samples was noted, which confirms that phages interfere with the structure of E. faecalis biofilm by killing bacterial cells and affecting extracellular polymer levels.}, } @article {pmid38138556, year = {2023}, author = {Qi, Y and Ji, P and Yin, K and Zheng, Y and Niu, J and Jia, A and Zhou, J and Li, J}, title = {Phloretin Inhibits Quorum Sensing and Biofilm Formation in Serratia marcescens.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {24}, pages = {}, doi = {10.3390/molecules28248067}, pmid = {38138556}, issn = {1420-3049}, support = {32000091//the National Natural Science Foundation of China/ ; TJ-2021-066//Jiangsu Youth Talent Promotion Project/ ; 22KJA550002//The Major Natural Science Research Project in Colleges and Universities of Jiangsu Province/ ; 222102310356//Henan Province Science and Technology Attack Plan Foundation/ ; 22B350004 and 23A350002//The Key Scientific Research Project of Higher Education of Henan Province/ ; 232102311164//The Key Scientific and Technological Project of Henan Province of China/ ; 202310482004//the innovative training program for college students in Henan Province of China/ ; }, abstract = {This study investigated the antivirulence capacity and mechanism of apple-skin-derived phloretin against Serratia marcescens NJ01, a vegetable spoilage bacterium. At 0.5 to 2 mg/mL doses, phloretin considerably inhibited the secretion of acyl homoserine lactones (AHLs), indicating that phloretin disrupted quorum sensing (QS) in S. marcescens NJ01. The dysfunction of QS resulted in reduced biofilms and the decreased production of protease, prodigiosin, extracellular polysaccharides (EPSs), and swimming and swarming motilities. Dysfunctional QS also weakened the activity of antioxidant enzymes and improved oxidative injury. The improved oxidative injury changed the composition of the membrane, improved membrane permeability, and eventually increased the susceptibility of biofilm cells to amikacin, netilmicin, and imipenem. The disrupted QS and enhanced oxidative stress also caused disorders of amino acid metabolism, energy metabolism, and nucleic acid metabolism, and ultimately attenuated the ability of S. marcescens NJ01 to induce spoilage. Our results indicated that phloretin can act as a potent drug to defend against spoilage by S. marcescens.}, } @article {pmid38138002, year = {2023}, author = {Ramírez Castillo, FY and Guerrero Barrera, AL and Harel, J and Avelar González, FJ and Vogeleer, P and Arreola Guerra, JM and González Gámez, M}, title = {Biofilm Formation by Escherichia coli Isolated from Urinary Tract Infections from Aguascalientes, Mexico.}, journal = {Microorganisms}, volume = {11}, number = {12}, pages = {}, doi = {10.3390/microorganisms11122858}, pmid = {38138002}, issn = {2076-2607}, support = {PIB19-3//Autonomous University of Aguascalientes/ ; 373176//Consejo Nacional de Humanidades, Ciencias y Tecnologías/ ; }, abstract = {Uropathogenic Escherichia coli (UPEC) strains are among the leading causes of urinary tract infections (UTIs) worldwide. They can colonize the urinary tract and form biofilms that allow bacteria to survive and persist, causing relapses of infections and life-threatening sequelae. Here, we analyzed biofilm production, antimicrobial susceptibility, virulence factors, and phylogenetic groups in 74 E. coli isolated from diagnosed patients with UTIs to describe their microbiological features and ascertain their relationship with biofilm capabilities. High levels of ceftazidime resistance are present in hospital-acquired UTIs. Isolates of multidrug resistance strains (p = 0.0017) and the yfcV gene (p = 0.0193) were higher in male patients. All the strains tested were able to form biofilms. Significant differences were found among higher optical densities (ODs) and antibiotic resistance to cefazolin (p = 0.0395), ceftazidime (p = 0.0302), and cefepime (p = 0.0420). Overall, the presence of fimH and papC coincided with strong biofilm formation by UPEC. Type 1 fimbriae (p = 0.0349), curli (p = 0.0477), and cellulose (p = 0.0253) production was significantly higher among strong biofilm formation. Our results indicated that high antibiotic resistance may be related to male infections as well as strong and moderate biofilm production. The ability of E. coli strains to produce biofilm is important for controlling urinary tract infections.}, } @article {pmid38136707, year = {2023}, author = {Barbarossa, A and Rosato, A and Carrieri, A and Tardugno, R and Corbo, F and Clodoveo, ML and Fracchiolla, G and Carocci, A}, title = {Antifungal Biofilm Inhibitory Effects of Combinations of Diclofenac and Essential Oils.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/antibiotics12121673}, pmid = {38136707}, issn = {2079-6382}, abstract = {Systemic fungal infections have risen in recent decades and most of them are caused by Candida species, which are becoming increasingly resistant to conventional antifungal drugs. Biofilm production has been considered the most common growth form of Candida cells and is associated with a high level of antifungal resistance. At present, international research reports on the antifungal activity of non-traditional antimicrobial drugs and their potential use against life-threatening resistant fungal infections. Indeed, drug repurposing has led to the consideration of well-known compounds as a last-line therapy. The goal of this work is to evaluate the potential synergistic antifungal biofilm activity of new combinations between diclofenac sodium salt (DSS), a widely used non-steroidal anti-inflammatory drug (NSAID), with the essential oils (EOs) of Mentha piperita, Pelargonium graveolens, and Melaleuca alternifolia, whose antifungal activity has been well documented over the years. The in vitro antifungal activity of DSS and EOs was determined on different Candida strains. Susceptibility testing and the synergism of DSS and EOs versus biofilm cells was performed by using the broth microdilution assay and checkerboard methods. Minimum inhibitory concentrations (sMIC50) of DSS alone ranged from 1.25 to 2.05 mg/mL for all the strains considered. These values significantly decreased when the drug was used in combination with the EOs. The fractional inhibitory concentration index (FICI) was lower than 0.5 for almost all the associations, thus indicating a significant synergism, particularly for the DSS-Pelargonium graveolens combination towards the Candida strains examined. These preliminary results show that the combination of the EOs with DSS improves the antifungal activity on all the tested Candida strains, significantly lowering the concentrations of the components used and thus allowing any toxic effects to be overcome.}, } @article {pmid38136705, year = {2023}, author = {Nowicka, J and Janczura, A and Pajączkowska, M and Chodaczek, G and Szymczyk-Ziółkowska, P and Walczuk, U and Gościniak, G}, title = {Effect of Camel Peptide on the Biofilm of Staphylococcus epidermidis and Staphylococcus haemolyticus Formed on Orthopedic Implants.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/antibiotics12121671}, pmid = {38136705}, issn = {2079-6382}, support = {SUBZ.A130.23.070//Ministry of Health/ ; }, abstract = {The increasing bacterial drug resistance and the associated challenges in the treatment of infections warrant the search for alternative therapeutic methods. Hope is placed in antimicrobial peptides, which have a broad spectrum of action and are effective against strains which are resistant to conventional antibiotics. Antimicrobial peptides are also tested for their efficacy in the treatment of infections associated with the formation of biofilm. The aim of the present study was to examine the effect of Camel peptide on S. epidermidis and S. haemolyticus adhesion to and formation of biofilm on steel cortical bone screws and also on the process of reducing mature biofilm in orthopedic implants. The tests were performed on steel implants for osteosynthesis. The MIC value and MBEC values of the peptide were determined using the microdilution method in microtiter plates. The effect of the peptide on adhesion and biofilm formation, as well as on the activity on the preformed biofilm, was evaluated using quantitative methods and confocal microscopy. The presented research results indicate that the peptide exhibits very good antimicrobial properties against the analyzed strains. Concentrations above MIC reduced biofilm in the range of 90-99%.}, } @article {pmid38134689, year = {2023}, author = {Zhu, X and Xiang, Q and Chen, L and Chen, J and Wang, L and Jiang, N and Hao, X and Zhang, H and Wang, X and Li, Y and Omer, R and Zhang, L and Wang, Y and Zhuang, Y and Huang, J}, title = {Engineered Bacillus subtilis Biofilm@Biochar living materials for in-situ sensing and bioremediation of heavy metal ions pollution.}, journal = {Journal of hazardous materials}, volume = {465}, number = {}, pages = {133119}, doi = {10.1016/j.jhazmat.2023.133119}, pmid = {38134689}, issn = {1873-3336}, abstract = {The simultaneous sensing and remediation of multiple heavy metal ions in wastewater or soil with microorganisms is currently a significant challenge. In this study, the microorganism Bacillus subtilis was used as a chassis organism to construct two genetic circuits for sensing and adsorbing heavy-metal ions. The engineered biosensor can sense three heavy metal ions (0.1-75 μM of Pb[2+] and Cu[2+], 0.01-3.5 μM of Hg[2+]) in situ real-time with high sensitivity. The engineered B. subtilis TasA-metallothionein (TasA-MT) biofilm can specifically adsorb metal ions from the environment, exhibiting remarkable removal efficiencies of 99.5% for Pb[2+], 99.9% for Hg[2+]and 99.5% for Cu[2+] in water. Furthermore, this engineered strain (as a biosensor and absorber of Pb[2+], Cu[2+], and Hg[2+]) was incubated with biochar to form a hybrid biofilm@biochar (BBC) material that could be applied in the bioremediation of heavy metal ions. The results showed that BBC material not only significantly reduced exchangeable Pb[2+] in the soil but also reduced Pb[2+] accumulation in maize plants. In addition, it enhanced maize growth and biomass. In conclusion, this study examined the potential applications of biosensors and hybrid living materials constructed using sensing and adsorption circuits in B. subtilis, providing rapid and cost-effective tools for sensing and remediating multiple heavy metal ions (Pb[2+], Hg[2+], and Cu[2+]).}, } @article {pmid38133388, year = {2023}, author = {Jiang, C and Almuhtaram, H and McKie, MJ and Andrews, RC}, title = {Assessment of Biofilm Growth on Microplastics in Freshwaters Using a Passive Flow-Through System.}, journal = {Toxics}, volume = {11}, number = {12}, pages = {}, doi = {10.3390/toxics11120987}, pmid = {38133388}, issn = {2305-6304}, support = {Industrial Research Chair in Drinking Water Treatment//Natural Sciences and Engineering Research Council/ ; GCXE21S054//Environment and Climate Change Canada/ ; }, abstract = {Biofilms that colonize on the surface of microplastics (MPs) in freshwaters may pose a potential health risk. This study examined factors that influence MP-associated biofilm growth, including polymer type, degree of weathering, and source water quality. Weathered MPs produced in-lab were employed in biofilm trials conducted on site using a passive flow-through system with raw water at drinking water treatment facility intakes. Adenosine triphosphate (ATP) was used to quantify biofilm abundance; biofilm composition was assessed via metagenomic sequencing. Biofilm growth was observed on all polymer types examined and most prevalent on polyvinyl chloride (PVC), where ATP levels were 6 to 12 times higher when compared to other polymers. Pathogen-containing species including Salmonella enterica and Escherichia coli were present on all polymers with relative abundance up to 13.7%. S. enterica was selectively enriched on weathered MPs in specific water matrices. These findings support the need to research the potential accumulation of pathogenic organisms on microplastic surfaces.}, } @article {pmid38133332, year = {2023}, author = {Mitropoulou, G and Kompoura, V and Nelios, G and Kourkoutas, Y}, title = {Pathogenic Biofilm Removal Potential of Wild-Type Lacticaseibacillus rhamnosus Strains.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/pathogens12121449}, pmid = {38133332}, issn = {2076-0817}, support = {HFRI-FM17-2496//Hellenic Foundation for Research and Innovation (H.F.R.I.)/ ; }, abstract = {The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatants (CFSs) of five wild-type Lacticaseibacillus rhamnosus strains, isolated from Greek natural products, in comparison to the commercially available L. rhamnosus GG strain, against biofilms formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). The biofilm removal activity of LAB was assessed on a two-day-old mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. The biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, with ranges of 60-89% and 30-80%, respectively. The biofilm removal efficiency of L. rhamnosus OLXAL-3 was significantly higher among the wild-type L. rhamnosus strains tested (20-100% v/v). In conclusion, our results suggest the great potential of the application of wild-type L. rhamnosus strain' CFSs as effective natural agents against pathogenic bacterial biofilms.}, } @article {pmid38133330, year = {2023}, author = {Díaz-Formoso, L and Silva, V and Contente, D and Feito, J and Hernández, PE and Borrero, J and Igrejas, G and Del Campo, R and Muñoz-Atienza, E and Poeta, P and Cintas, LM}, title = {Antibiotic Resistance Genes, Virulence Factors, and Biofilm Formation in Coagulase-Negative Staphylococcus spp. Isolates from European Hakes (Merluccius merluccius, L.) Caught in the Northeast Atlantic Ocean.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/pathogens12121447}, pmid = {38133330}, issn = {2076-0817}, support = {RTI2018-094907-B-I00 and PID2019-104808RA-I00//Ministerio de Ciencia, Innovación y Universidades (Spain)/ ; UIDB/50006/2020, UIDP/50006/2020, UIDB/CVT/00772/2020, and LA/P/0059/2020//Fundação para a Ciência e a Tecnologia (FCT, Portugal)/ ; Programa Investigo//Ministerio de Trabajo y Economı́a Social (MITES, Spain) funded by the EU (NextGenerationEU)./ ; PhD grant (SFRH/BD/137947/2018FCT)//Fundação para a Ciência e a Tecnologia (FCT, Portugal)/ ; FEI16/54 contract and a predoctoral contract//Universidad Complutense de Madrid (UCM, Spain)/ ; Programa Atracción de Talento (2018-T1/BIO-10158)//Comunidad de Madrid (Spain)/ ; }, abstract = {The indiscriminate use of antibiotics has contributed to the dissemination of multiresistant bacteria, which represents a public health concern. The aim of this work was to characterize 27 coagulase-negative staphylococci (CoNS) isolated from eight wild Northeast Atlantic hakes (Merluccius merluccius, L.) and taxonomically identified as Staphylococcus epidermidis (n = 16), Staphylococcus saprophyticus (n = 4), Staphylococcus hominis (n = 3), Staphylococcus pasteuri (n = 2), Staphylococcus edaphicus (n = 1), and Staphylococcus capitis (n = 1). Biofilm formation was evaluated with a microtiter assay, antibiotic susceptibility testing was performed using the disk diffusion method, and antibiotic resistance and virulence determinants were detected by PCR. Our results showed that all staphylococci produced biofilms and that 92.6% of the isolates were resistant to at least one antibiotic, mainly penicillin (88.8%), fusidic acid (40.7%), and erythromycin (37%). The penicillin resistance gene (blaZ) was detected in 66.6% (18) of the isolates, of which 10 also carried resistance genes to macrolides and lincosamides (mphC, msr(A/B), lnuA, or vgaA), 4 to fusidic acid (fusB), and 3 to trimethoprim-sulfamethoxazole (dfrA). At least one virulence gene (scn, hla, SCCmecIII, and/or SCCmecV) was detected in 48% of the isolates. This study suggests that wild European hake destined for human consumption could act as a vector of CoNS carrying antibiotic resistance genes and/or virulence factors.}, } @article {pmid38133282, year = {2023}, author = {Sun, X and Pu, B and Qin, J and Xiang, J}, title = {Effect of a Depolymerase Encoded by Phage168 on a Carbapenem-Resistant Klebsiella pneumoniae and Its Biofilm.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/pathogens12121396}, pmid = {38133282}, issn = {2076-0817}, abstract = {Infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) are becoming increasingly common within clinical settings, requiring the development of alternative therapies. In this study, we isolated, characterized, and sequenced the genome of a CRKP phage, Phage168. The total genomic DNA of Phage168 was 40,222 bp in length, encoding 49 predicted proteins. Among these proteins, Dep40, the gene product of ORF40, is a putative tail fiber protein that exhibits depolymerase activity based on the result of bioinformatics analyses. In vitro, we confirmed that the molecular weight of the Phage168 depolymerase protein was about 110 kDa, the concentration of the produced phage 168 depolymerase protein was quantified as being 1.2 mg/mL, and the depolymerase activity was still detectable after the dilution of 1.2 µg/mL. This recombinant depolymerase exhibited enzyme activity during the depolymerization of the formed CRKP biofilms. We also found that depolymerase, when combined with polymyxin B, was able to enhance the bactericidal effect of polymyxin B on CRKP strains by disrupting their biofilm. When recombinant depolymerase was used in combination with human serum, it enhanced the sensitivity of the CRKP strain UA168 to human serum, and the synergistic bactericidal effect reached the strongest level when the ratio of depolymerase to human serum was 3:1. Our results indicated that depolymerase encoded by Phage168 may be a promising strategy for combating infections caused by drug-resistant CRKP formed within the biofilm.}, } @article {pmid38133260, year = {2023}, author = {Nisbett, LM and Previti, ML and Seeliger, JC}, title = {A Loss of Function in LprG-Rv1410c Homologues Attenuates Growth during Biofilm Formation in Mycobacterium smegmatis.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {12}, pages = {}, doi = {10.3390/pathogens12121375}, pmid = {38133260}, issn = {2076-0817}, support = {R01 AI14153; K12GM102778/NH/NIH HHS/United States ; }, abstract = {MmpL (mycobacterial membrane protein large) proteins are integral membrane proteins that have been implicated in the biosynthesis and/or transport of mycobacterial cell wall lipids. Given the cellular location of these proteins, however, it is unclear how cell wall lipids are transported beyond the inner membrane. Moreover, given that mycobacteria grow at the poles, we also do not understand how new cell wall is added in a highly localized and presumably coordinated manner. Here, we examine the relationship between two lipid transport pathways associated with the proteins MmpL11 and LprG-Rv1410c. The lipoprotein LprG has been shown to interact with proteins involved in cell wall processes including MmpL11, which is required in biofilms for the surface localization of certain lipids. Here we report that deletion of mmpL11 (MSMEG_0241) or the lprG-rv1410c operon homologues MSMEG_3070-3069 in Mycobacterium smegmatis produced similar biofilm defects that were distinct from that of the previously reported mmpL11 transposon insertion mutant. Analysis of pellicle biofilms, bacterial growth, lipid profiles, and gene expression revealed that the biofilm phenotypes could not be directly explained by changes in the synthesis or localization of biofilm-related lipids or the expression of biofilm-related genes. Instead, the shared biofilm phenotype between ΔMSMEG_3070-3069 and ΔmmpL11 may be related to their modest growth defect, while the origins of the distinct mmpL11::Tn biofilm defect remain unclear. Our findings suggest that the mechanisms that drive pellicle biofilm formation in M. smegmatis are not connected to crosstalk between the LprG-Rv1410c and MmpL11 pathways and that any functional interaction between these proteins does not relate directly to their lipid transport function.}, } @article {pmid38132912, year = {2023}, author = {Akkoyunlu, B and Daly, S and Cerrone, F and Casey, E}, title = {Investigating Mass Transfer and Reaction Engineering Characteristics in a Membrane Biofilm Using Cupriavidus necator H16.}, journal = {Membranes}, volume = {13}, number = {12}, pages = {}, doi = {10.3390/membranes13120908}, pmid = {38132912}, issn = {2077-0375}, support = {16/RC/3889/SFI_/Science Foundation Ireland/Ireland ; }, abstract = {Membrane biofilm reactors are a growing trend in wastewater treatment whereby gas-transfer membranes provide efficient bubbleless aeration. Recently, there has been a growing interest in using these bioreactors for industrial biotechnology using microorganisms that can metabolise gaseous substrates. Since gas fermentation is limited by the low solubilities of gaseous substrates in liquid media, it is critical to characterise mass transfer rates of gaseous substrates to enable the design of membrane biofilm reactors. The objective of this study is to measure and analyse mass transfer rates and reaction engineering characteristics for a single tube membrane biofilm reactor using Cupriavidus necator H16. At elevated Reynolds numbers, the dominant resistance for gas diffusion shifts from the liquid boundary layer to the membrane. The biofilm growth rate was observed to decrease after 260 μm at 96 h. After 144 h, some sloughing of the biofilm occurred. Oxygen uptake rate and substrate utilisation rate for the biofilm developed showed that the biofilm changes from a single-substrate limited regime to a dual-substrate-limited regime after 72 h which alters the localisation of the microbial activity within the biofilm. This study shows that this platform technology has potential applications for industrial biotechnology.}, } @article {pmid38132911, year = {2023}, author = {Cintra Moreira, MV and Figueiredo, LC and da Cunha Melo, MAR and Uyeda, FH and da Silva, LDA and Macedo, TT and Sacco, R and Mourão, CF and Shibli, JA and Bueno-Silva, B}, title = {Evaluation of the Microbial Profile on the Polydioxanone Membrane and the Collagen Membrane Exposed to Multi-Species Subgingival Biofilm: An In Vitro Study.}, journal = {Membranes}, volume = {13}, number = {12}, pages = {}, doi = {10.3390/membranes13120907}, pmid = {38132911}, issn = {2077-0375}, abstract = {Dehiscence in surgeries involving membranes often leads to bacterial contamination, hindering the healing process. This study assessed bacterial colonization on various membrane materials. Polydioxanone (PDO) membranes, with thicknesses of 0.5 mm and 1 mm, and a collagen membrane were examined. Packages containing polystyrene pins were crafted using these membranes, attached to 24-well plates, and exposed to oral bacteria from supra and subgingival biofilm. After a week's anaerobic incubation, biofilm formation was evaluated using the DNA-DNA hybridization test. Statistical analysis employed the Kruskal-Wallis test with Dunn's post hoc test. The biofilm on the polystyrene pins covered by the 0.5 mm PDO membrane showed a higher count of certain pathogens. The collagen membrane had a greater total biofilm count on its inner surface compared to both PDO membranes. The external collagen membrane face had a higher total biofilm count than the 0.5 mm PDO membrane. Furthermore, the 1 mm PDO membrane exhibited a greater count of specific pathogens than its 0.5 mm counterpart. In conclusion, the collagen membrane presented more biofilm and pathogens both internally and on its inner surface.}, } @article {pmid38132801, year = {2023}, author = {Brilhante, RSN and Costa, ADC and Mesquita, JRL and Dos Santos Araújo, G and Freire, RS and Nunes, JVS and Nobre, AFD and Fernandes, MR and Rocha, MFG and Pereira Neto, WA and Crouzier, T and Schimpf, U and Viera, RS}, title = {Antifungal Activity of Chitosan against Histoplasma capsulatum in Planktonic and Biofilm Forms: A Therapeutic Strategy in the Future?.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, doi = {10.3390/jof9121201}, pmid = {38132801}, issn = {2309-608X}, abstract = {Histoplasmosis is a respiratory disease caused by Histoplasma capsulatum, a dimorphic fungus, with high mortality and morbidity rates, especially in immunocompromised patients. Considering the small existing therapeutic arsenal, new treatment approaches are still required. Chitosan, a linear polysaccharide obtained from partial chitin deacetylation, has anti-inflammatory, antimicrobial, biocompatibility, biodegradability, and non-toxicity properties. Chitosan with different deacetylation degrees and molecular weights has been explored as a potential agent against fungal pathogens. In this study, the chitosan antifungal activity against H. capsulatum was evaluated using the broth microdilution assay, obtaining minimum inhibitory concentrations (MIC) ranging from 32 to 128 µg/mL in the filamentous phase and 8 to 64 µg/mL in the yeast phase. Chitosan combined with classical antifungal drugs showed a synergic effect, reducing chitosan's MICs by 32 times, demonstrating that there were no antagonistic interactions relating to any of the strains tested. A synergism between chitosan and amphotericin B or itraconazole was detected in the yeast-like form for all strains tested. For H. capsulatum biofilms, chitosan reduced biomass and metabolic activity by about 40% at 512 µg/mL. In conclusion, studying chitosan as a therapeutic strategy against Histoplasma capsulatum is promising, mainly considering its numerous possible applications, including its combination with other compounds.}, } @article {pmid38132405, year = {2023}, author = {AlKanderi, S and AlFreeh, M and Bhardwaj, RG and Karched, M}, title = {Sugar Substitute Stevia Inhibits Biofilm Formation, Exopolysaccharide Production, and Downregulates the Expression of Streptococcal Genes Involved in Exopolysaccharide Synthesis.}, journal = {Dentistry journal}, volume = {11}, number = {12}, pages = {}, doi = {10.3390/dj11120267}, pmid = {38132405}, issn = {2304-6767}, support = {SRUL 01/14//Kuwait University/ ; }, abstract = {BACKGROUND: Acid production by sucrose fermentation disturbs the balance in dental plaque by lowering the oral pH. As a consequence of the profound effect of sucrose on caries initiation and progression, many studies have been directed towards finding non-cariogenic artificial sweeteners that can be used as a substitute to sucrose. Existing literature shows that dietary sucrose upregulates the expression of biofilm associated genes involved in exopolysaccharide (EPS) production.

OBJECTIVE: In this study, we aimed to investigate the effect of the sugar substitute stevia on biofilm formation, EPS secretion, and streptococcal genes encoding glucan-binding proteins (Gbps) and glucosyltransferases (Gtfs), which are essential for the synthesis of EPS.

MATERIALS AND METHODS: Streptococcus mutans and Streptococcus gordonii were grown as biofilm cultures with or without stevia and sucrose. Biomass was quantified for biofilm and EPS production by crystal violet staining and the phenol-sulfuric acid method, respectively. Expression of gtfB and gbpB genes was studied by RT-PCR.

RESULTS: The quantities of biofilm were significantly lower when grown in the presence of stevia compared to sucrose in both species (p < 0.05). The proportion of EPS in the biofilm pellet decreased with increasing concentrations of stevia in both species but remained nearly unchanged with sucrose with respect to the control. In both streptococcal species, exposure of stevia decreased the expression of gtfB and gbpB genes compared to sucrose (p < 0.05). In comparison to the untreated control, the expression was decreased in the presence of stevia in both species, while it increased 2.5- to 4-fold in S. mutans and 1.5- to 2.5-fold in S. gordonii in the presence of sucrose.

CONCLUSION: The ability of stevia to inhibit biofilm formation, reduce EPS production, and downregulate the expression of gtfB and gbpB genes in S. mutans and S. gordonii may have potential therapeutic applications in controlling dental plaques and caries.}, } @article {pmid38129976, year = {2023}, author = {Paschoal, MAB and Gonçalves, LM and Cavalcante, SIA and Andrade-Maia, G and Duarte, S}, title = {Morphological changes and viability of Streptococcus mutans biofilm treated with erythrosine: A confocal laser scanning microscopy analysis.}, journal = {Microscopy research and technique}, volume = {}, number = {}, pages = {}, doi = {10.1002/jemt.24477}, pmid = {38129976}, issn = {1097-0029}, support = {//Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão/ ; }, abstract = {Antimicrobial photodynamic therapy (a-PDT) is a modality that aims to induce microorganisms through visible light, a photosensitizer, and molecular oxygen. This therapy has shown promising results in controlling cariogenic biofilm in vitro and in vivo counterparts. This study investigated bacterial viability and morphological characterization of Streptococcus mutans mature biofilms after combination of erythrosine and a high potency dental curing light. Biofilms were formed on saliva-coated hydroxyapatite disks in batch culture. The samples were performed in triplicates. Fresh medium was replaced daily for five days and treated using 40 μM of E activated by HL 288 J/cm[2] and total dose of 226 J at 1200 mW/cm[2] . Phosphate buffer saline and 0.12% of chlorhexidine were used as negative and positive control, respectively. After treatment, biofilms were assessed for microbial viability and morphological characterization by means of bio-volume and thickness. COMSTAT software was used for image analysis. Data were analyzed using two-way ANOVA followed by Tukey test with significance level 5%. The application of a-PDT and CHX treatments decreased S. mutans bacterial viability. The image analysis showed more red cells on biofilms when compared to other groups, demonstrating photobacterial killing. Erythrosine irradiated with a high potency curing light can potentially act as an antimicrobial tool in the treatment of cariogenic biofilms. The morphology and viability of microorganisms were impacted after treatment. Treatment with photodynamic therapy may be able to reduce the bio-volume and viability of bacteria present in biofilms. CLINICAL RELEVANCE AND RESEARCH HIGHLIGHTS: The use of the a-PDT technique has been applied in dentistry with satisfactory results. Some applications of this technique are in stomatology and endodontics. In the present study, we sought to understand the use of photodynamic therapy in the control of biofilm and the results found are compatible with the objective of microbiological control proposed by this technique, thus raising the alert for future studies in vivo using the combination of a-PDT with erythrosine, since they are easily accessible materials for the dental surgeon and can be applied in clinical practice.}, } @article {pmid38129064, year = {2024}, author = {Sarquis, A and Ladero, V and Díaz, M and Sánchez-Llana, E and Fernández, M and Alvarez, MA}, title = {The gene cluster associated with strong biofilm-formation capacity by histamine-producing Lentilactobacillus parabuchneri encodes a sortase-mediated pilus and is located on a plasmid.}, journal = {Food research international (Ottawa, Ont.)}, volume = {175}, number = {}, pages = {113777}, doi = {10.1016/j.foodres.2023.113777}, pmid = {38129064}, issn = {1873-7145}, abstract = {Histamine is a biogenic amine synthesized through the enzymatic decarboxylation of the amino acid histidine. It can accumulate at high concentrations in foods through the metabolism of certain bacteria, sometimes leading to adverse reactions in consumers. In cheese, histamine can accumulate at toxic levels; Lentilactobacillus parabuchneri has been identified the major cause of this problem. Previous studies have shown some L. parabuchneri strains to form biofilms on different surfaces, posing a contamination risk during cheese production, particularly for cheeses that are processed post-ripening (e.g., grating or slicing). The food contamination they cause can result in economic losses and even foodborne illness if histamine accumulates in the final product. The aim of the present work was to identify the genes of L. parabuchneri involved in biofilm formation, and to determine their function. The genomes of six strains with different biofilm-production capacities (strong, moderate and weak) were sequenced and analysed. A cluster of four genes, similar to those involved in sortase-mediated pilus formation, was identified in the strong biofilm-producers, suggesting it to have a role in surface adhesion. Cloning and heterologous expression in Lactococcus cremoris NZ9000 confirmed its functionality and involvement in adhesion and, therefore, in biofilm formation. PacBio sequencing showed this cluster to be located on a 33.4 kb plasmid, which might increase its chances of horizontal transmission. These findings provide insight into the genetic factors associated with biofilm formation in histamine-producing L. parabuchneri, and into the risks associated with this bacterium in cheese production.}, } @article {pmid38129021, year = {2024}, author = {Ashikur Rahman, M and Akter, S and Ashrafudoulla, M and Anamul Hasan Chowdhury, M and Uddin Mahamud, AGMS and Hong Park, S and Ha, SD}, title = {Insights into the mechanisms and key factors influencing biofilm formation by Aeromonas hydrophila in the food industry: A comprehensive review and bibliometric analysis.}, journal = {Food research international (Ottawa, Ont.)}, volume = {175}, number = {}, pages = {113671}, doi = {10.1016/j.foodres.2023.113671}, pmid = {38129021}, issn = {1873-7145}, abstract = {Biofilm formation by Aeromonas hydrophila in the food industry poses significant challenges to food safety and quality. Therefore, this comprehensive review aimed to provide insights into the mechanisms and key factors influencing A. hydrophila biofilm formation. It explores the molecular processes involved in initial attachment, microcolony formation, and biofilm maturation; moreover, it concurrently examines the impact of intrinsic factors, including quorum sensing, cyclic-di-GMP, the efflux pump, and antibiotic resistance, as well as environmental conditions, such as temperature, nutrient availability, and osmotic pressure, on biofilm architecture and resilience. Furthermore, the article highlights the potential of bibliometric analysis as a promising method for conceptualizing the research landscape of and identifying knowledge gaps in A. hydrophila biofilm research. The findings underscore the requirement for focused interventions that prevent biofilm development and raise food sector safety. The consolidation of current information and incorporation of bibliometric analysis enhances existing understanding of A. hydrophila biofilm formation and offers insights for future research and control strategies within a food industry context.}, } @article {pmid38128797, year = {2023}, author = {El-Newehy, MH and Aldalbahi, A and Thamer, BM and Hameed, MMA}, title = {Establishment and inactivation of mono-species biofilm in a pilot-scale water distribution system using nanocomposite of silver nanoparticles/montmorillonite loaded cationic chitosan.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128874}, doi = {10.1016/j.ijbiomac.2023.128874}, pmid = {38128797}, issn = {1879-0003}, abstract = {This study presents a novel approach in the synthesis and characterization of nanocomposites comprising cationic chitosan (CCS) blended with varying concentrations of silver nanoparticles/montmorillonite (AgNPs/MMT). The AgNPs/MMT was synthesized using soluble starch as a reducing and stabilizing agent. Subsequently, nanocomposites, namely CCS/AgMMT-0, CCS/AgMMT-0.5, CCS/AgMMT-1.5, and CCS/AgMMT-2.5, were developed by blending 2.5 g of CCS with 0, 0.5, 1.5, and 2.5 g of AgNPs/MMT, respectively, via ball milling. Transmission electron microscopy (TEM) analysis revealed the formation of nanocomposites exhibiting nearly spherical morphologies. Dynamic light scattering (DLS) measurements displayed average particle sizes of 1183 nm, 131 nm, 140 nm, and 188 nm for CCS/AgMMT-0, CCS/AgMMT-0.5, CCS/AgMMT-1.5, and CCS/AgMMT-2.5, respectively. The narrow polydispersity index (~0.5) indicated uniform particle size distributions across the nanocomposites, affirming monodispersity. Moreover, the zeta potential values exceeding 30 mV across all nanocomposites confirmed their stability against agglomeration. Notably, the CCS/AgMMT-2.5 nanocomposite exhibited potent antibacterial and antibiofilm properties against diverse pipeline materials. Findings showed that after 15 days of incubation, the highest populations of biofilm cells, Pseudomonas aeruginosa biofilm developed over UPVC, MDPE, DCI, and SS, with corresponding HPCs of 4.79, 6.38, 8.81, and 7.24 CFU/cm[2]. The highest cell densities of Enterococcus faecalis biofilm in the identical situation were 4.19, 5.89, 8.12, and 6.9 CFU/cm[2]. The nanocomposite CCS/AgMMT-2.5 exhibited the largest measured zone of inhibition (ZOI) against both P. aeruginosa and E. faecalis, with calculated ZOI values of 19 ± 0.65 and 17 ± 0.21 mm, respectively. Remarkably, the research indicates that the youngest biofilm exhibited the most notable rate of inactivation when exposed to a dose of 150 mg/L, in comparison to the mature biofilm. These findings offer valuable insights into the development of effective antibiofilm agents and materials applicable in diverse sectors such as water treatment, medical devices, and industrial pipelines.}, } @article {pmid38128496, year = {2023}, author = {Usuga-Vacca, M and Marquez-Ortiz, RA and Castellanos, JE and Martignon, S}, title = {Association of Root Biofilm Bacteriome with Root Caries Lesion Severity and Activity.}, journal = {Caries research}, volume = {}, number = {}, pages = {}, doi = {10.1159/000535923}, pmid = {38128496}, issn = {1421-976X}, abstract = {INTRODUCTION: This research aimed to assess the association of root biofilm bacteriome with root caries lesion severity and activity in institutionalised Colombian elderlies and was conducted to gather data on the root caries bacteriome in this population.

METHODS: A bacteriome evaluation of biofilm samples from sound, and carious root surfaces was performed. Root caries was categorised (ICDAS Root criteria) based on severity (Sound surfaces, Initial: non-cavitated, Moderate/Extensive combined: cavitated) and activity status (Active and Inactive). DNA was extracted and the V4 region of the 16S rRNA gene was sequenced, after the classification of features employing amplicon sequence variants (ASVs) and taxonomic assignment via the Human Oral Microbiome Database (HOMD). Bacterial richness, diversity (Simpson's and Shannon's indices), and relative abundance estimation were assessed and compared based on root caries severity and activity status (including Sound surfaces).

RESULTS: A total of 130 biofilm samples were examined: Sound (n=45) and with root caries lesions (n=85; Initial: n=41; Moderate/Extensive: n=44; Active: n=60; Inactive: n=25). Species richness was significantly lower in biofilms from Moderate/Extensive and Active groups compared to Sound sites. There was a higher relative abundance of species like Lechtotricia wadei, Capnocytophaga granulosa, Cardiobacterium valvarum, Porphyromonas pasteri -in Sound sites; Dialister invisus, Streptococcus mutans, Pseudoramibacter alactolyticus and Bacteroidetes (G-5) bacterium 511 -in Moderate/Extensive lesions, and Fusobacterium nucleatum subsp. animalis, Prevotella denticola, Lactobacillus fermentum, Saccharibacteria (TM7) [G-5] bacterium HMT 356 -in active lesions.

CONCLUSION: Root caries bacteriome exhibited differences in species proportions between the compared groups. Specifically, cavitated lesions and active lesions showed higher relative abundance of acidogenic bacteria.}, } @article {pmid38128407, year = {2023}, author = {Zhang, Q and Zhang, J and Zhang, Y and Sui, Y and Du, Y and Yang, L and Yin, Y}, title = {Antifungal and anti-biofilm activities of patchouli alcohol against Candida albicans.}, journal = {International journal of medical microbiology : IJMM}, volume = {314}, number = {}, pages = {151596}, doi = {10.1016/j.ijmm.2023.151596}, pmid = {38128407}, issn = {1618-0607}, abstract = {The opportunistic fungal pathogen Candida albicans could cause severe clinical outcomes which could be exacerbated by the scarcity of antifungals. The capacity of C. albicans to form biofilms on medical devices that are hard to eradicate, further deepen the need to develop antifungal agents. In this study, we, for the first time, showed that patchouli alcohol (PA) can inhibit the growth of multiple C. albicans strains, as well as four other Candida species, with MICs of 64 μg/mL and MFCs from 64 to 128 μg/mL. The biofilm formation and development, adhesion, yeast-to-hyphal transition and extracellular polysaccharide of C. albicans can be inhibited by PA in a concentration-dependent manner. Confocal microscopy analyses of cells treated with PA showed that PA can increase the membrane permeability and intracellular reactive oxygen species (ROS) production. In C. elegans, PA did not influence the survival below 64 μg/mL. In this study PA demonstrated antifungal and antibiofilm activity against C. albicans and our results showed the potential of developing PA to fight Candida infections.}, } @article {pmid38127462, year = {2023}, author = {Tokarz, Z and Krzysciak, P and Wieczorek, A}, title = {Effectiveness of methods for removing the Candida albicans biofilm from the dental acrylic surface.}, journal = {Dental and medical problems}, volume = {60}, number = {4}, pages = {665-671}, doi = {10.17219/dmp/150407}, pmid = {38127462}, issn = {2300-9020}, abstract = {BACKGROUND: Approximately half of the adult population in Europe have used some form of dental prosthesis. Much effort has been put into developing denture cleaning methods and the most recommended are brushing the prosthesis after meals and cleaning it with special liquids (sometimes prepared just before the procedure). However, these simple techniques are often omitted or insufficient due to, i.e., age-related mental or motor disabilities.

OBJECTIVES: The aim of the study was to compare a range of techniques that can be performed at home and do not require patient dexterity in order to find the most efficient method of reducing the viability of the C. albicans biofilm and removing it from acrylic surfaces.

MATERIAL AND METHODS: The 20 mm × 25 mm × 1 mm unpolished acrylic plates were inoculated with C. albicans and incubated for 72 h. Plates with formed biofilms were divided into 6 equal groups: a control group and 5 groups for different cleaning procedures: a dental cleaner with liquid, a dental cleaner with phosphate-buffered saline (PBS), air drying, antiseptic liquid, and an ultrasonic cleaner. Biofilm viability was assessed by plating serial dilutions and counting the colonies of C. albicans on the Sabouraud dextrose agar (SDA) medium.

RESULTS: The study found that both MultiClean fluid and Sonic-3 ultrasonic cleaner were effective against Candida cells. MultiClean fluid showed the strongest biocidal properties, both when used with the Sonic Denture Cleaner and independently.

CONCLUSIONS: Cleaning acrylic surfaces with a dental cleaner followed by antiseptic liquid is more effective than using these methods separately.}, } @article {pmid38126773, year = {2023}, author = {Vander Griend, JA and Isenberg, RY and Kotla, KR and Mandel, MJ}, title = {Transcriptional pathways across colony biofilm models in the symbiont Vibrio fischeri.}, journal = {mSystems}, volume = {}, number = {}, pages = {e0081523}, doi = {10.1128/msystems.00815-23}, pmid = {38126773}, issn = {2379-5077}, abstract = {The V. fischeri-squid system provides an opportunity to study biofilm development both in the animal host and in culture-based biofilm models that capture key aspects of in vivo signaling. In this work, we report the results of the transcriptomic profiling of two V. fischeri biofilm models followed by phenotypic validation and examination of novel signaling pathway architecture. Remarkable consistency between the models provides a strong basis for future studies using either approach or both. A subset of the factors identified by the approaches were validated in the work, and the body of transcriptomic data provides a number of leads for future studies in culture and during animal colonization.}, } @article {pmid38126106, year = {2023}, author = {Ping, L and Zhengyang, Z and Mohan, S and Ruihong, W and Zhengang, L and Wen, L and Xuemeng, J and Yue, C and Xinjun, D and Shuo, W}, title = {Effects and molecular mechanism of sugar transporter ESA_RS15745 on desiccation resistance, motility, and biofilm formation of Cronobacter sakazakii.}, journal = {Journal of food science}, volume = {}, number = {}, pages = {}, doi = {10.1111/1750-3841.16872}, pmid = {38126106}, issn = {1750-3841}, support = {31972167//National Natural Science Foundation of China/ ; 2018YFC1603800//National Key R&D Program of China/ ; No. SKLFNS-KF-202212//Open Project Program of State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science & Technology/ ; }, abstract = {Cronobacter sakazakii, an important Gram-negative foodborne pathogen, can cause neonatal meningitis and sepsis with high rates of infection and death. Gene ESA_RS15745 encodes a sugar transporter protein, which is not only essential for osmotic pressure maintenance during bacterial growth and reproduction but also associated with their desiccation tolerance, motility, and biofilm formation. Here, a mutant strain of ESA_RS15745 (ΔESA_RS15745) and the complementation strain (cpESA_RS15745) were constructed using a suicide vector knockout and gene complementation. ΔESA_RS15745 was found to have a decrease in its ability to transport maltose and trehalose and resist desiccation, whereas an increase in the ability of motility and biofilm formation, implying that ESA_RS15745 may positively regulate sugar transport and desiccation tolerance and negatively regulate motility and biofilm formation. To further investigate the molecular mechanisms underlying the function of related genes, RNA-seq was performed to explore the differentially expressed genes in the mutants. RNA-seq results showed the upregulation of 114 genes (mainly including those regulating chemotaxis and flagellar motility) and the downregulation of 22 genes (mainly including those regulating sugar transport). qRT-PCR analysis supported the RNA-seq results and showed that ESA_RS15745 may influence the dehydration tolerance though decreasing the intracellular trehalose content and negatively regulate the motility though the chemotactic signaling pathway. In addition, the biofilm formation of C. sakazakii should also be speculated to negatively regulate by ESA_RS15745 by consuming the extracellular carbohydrates concentration and then downregulating the intracellular cyclic diguanosine monophosphate. This study offers a reference for comprehending the molecular mechanism of gene ESA_RS15745 in C. sakazakii.}, } @article {pmid38125909, year = {2023}, author = {Díaz-Navarro, M and Samaniego, R and Piqueras, JC and Díez, R and Hafian, R and Manzano, I and Muñoz, P and Guembe, M}, title = {Understanding the diagnosis of catheter-related bloodstream infection: real-time monitoring of biofilm growth dynamics using time-lapse optical microscopy.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1286527}, pmid = {38125909}, issn = {2235-2988}, abstract = {BACKGROUND: The differential time to positivity (DTTP) technique is recommended for the conservative diagnosis of catheter-related bloodstream infection (C-RBSI). The technique is based on a 120-minute difference between microbial growth in blood drawn through the catheter and blood drawn through a peripheral vein. However, this cut-off has failed to confirm C-RBSI caused by Candida spp. and Staphylococcus aureus.

OBJECTIVE: We hypothesized that the biofilm of both microorganisms disperses faster than that of other microorganisms and that microbial load is rapidly equalized between catheter and peripheral blood. Therefore, our aim was to compare the biofilm dynamics of various microorganisms.

METHODS: Biofilm of ATCC strains of methicillin-resistant Staphylococcus epidermidis, methicillin-susceptible S. aureus, Enterococcus faecalis, Escherichia coli and Candida albicans was grown on silicon disks and analyzed using time-lapse optical microscopy. The time-lapse images of biofilms were processed using ImageJ2 software. Cell dispersal time and biofilm thickness were calculated.

RESULTS: The mean (standard deviation) dispersal time in C. albicans and S. aureus biofilms was at least nearly 3 hours lower than in biofilm of S. epidermidis, and at least 15 minutes than in E. faecalis and E. coli biofilms.

CONCLUSION: Our findings could explain why early dissemination of cells in C. albicans and S. aureus prevents us from confirming or ruling out the catheter as the source of the bloodstream infection using the cut-off of 120 minutes in the DTTP technique. In addition, DTTP may not be sufficiently reliable for E. coli since their dispersion time is less than the cut-off of 120 minutes.}, } @article {pmid38122995, year = {2023}, author = {Wang, X and Li, J and Xu, L and Su, J and Wang, Z and Li, X}, title = {Simultaneous removal of calcium, cadmium and tetracycline from reverse osmosis wastewater by sycamore deciduous biochar, shell powder and polyurethane sponge combined with biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130215}, doi = {10.1016/j.biortech.2023.130215}, pmid = {38122995}, issn = {1873-2976}, abstract = {The treatment of reverse osmosis concentrate generated from urban industrial sewage for resource recovery has been hot. In this research, a biofilm reactor was constructed by combining sycamore deciduous biochar, shell powder, and polyurethane sponge loaded with Zobellella denitrificans sp. LX16. For ammonia nitrogen (NH4[+]-N), calcium (Ca[2+]), chemical oxygen demand (COD), cadmium (Cd[2+]), and tetracycline (TC), the removal efficiencies were 98.69 %, 83.95 %, 97.26 %, 98.34 %, and 69.12 % at a hydraulic retention time (HRT) of 4 h, pH of 7.0, and influent salinity, Ca[2+], and TC concentrations of 1.0, 180.0, and 3.0 mg/L, respectively. The biofilm reactor packing has a three-dimensional structure to ensure good loading of microorganisms while promoting electron transfer and metabolic activity of microorganisms and increasing the pollutant tolerance and removal efficiency. The reactor provides a practical reference for the sedimentation of reverse osmosis concentrate to remove Cd[2+] and TC by microbial induced calcium precipitation (MICP).}, } @article {pmid38122875, year = {2023}, author = {Xiao, Z and Goraya, MU and Ali, L and Chen, X and Yu, D}, title = {Nitrogen and phosphorus eutrophication enhance biofilm-related drug resistance in Enterococcus faecalis isolated from Water Sources.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106501}, doi = {10.1016/j.micpath.2023.106501}, pmid = {38122875}, issn = {1096-1208}, abstract = {Antibiotic resistance is a critical topic worldwide with important consequences for public health. So considering the rising issue of antibiotic-resistance in bacteria, we explored the impact of nitrogen and phosphorus eutrophication on drug resistance mechanisms in Enterococcus faecalis, especially ciprofloxacin, oxytetracycline, and ampicillin. For this purpose we examined the antibiotic-resistance genes and biofilm formation of Enterococcus faecalis under different concentration of nitrogen and phosphorus along with mentioned antibiotics. Mesocosms were designed to evaluate the impact of influence of eutrophication on the underlying mechanism of drugn resistence in Enterococcus faecalis. For this purpose, we explored the potential relation to biofilm formation, adhesion ability, and the expression levels of the regulatory gene fsrA and the downstream gene gelEI. Our results demonstrated that the isolates of all treatments displayed high biofilm forming potential, and fsrA and gelE genes expression. Additionally, the experimental group demonstrated substantially elevated Enterococcus faecalis gelE expression. Crystal violet staining was applied to observe biofilm formation during bacterial development phase and found higher biofilm formation. In conclusion, our data suggest that E. faecalis resistance to ciprofloxacin, oxytetracycline, and ampicillin is related to biofilm development. Also, the high level of resistance in Enterococcus faecalis is linked to the expression of the fsrA and gelE genes. Understanding these pathways is vital in tackling the rising problem of bacterial resistance and its potential effect on human health.}, } @article {pmid38122835, year = {2023}, author = {Alves de Melo Fernandes, T and Rafaella Costa, T and de Paula Menezes, R and Arantes de Souza, M and Gomes Martins, CH and Junior, NN and Gobbi Amorim, F and Quinton, L and Polloni, L and Teixeira, SC and Amália Vieira Ferro, E and Soares, AM and de Melo Rodrigues Ávila, V}, title = {Bothrops snake venom L-amino acid oxidases impair biofilm formation of clinically relevant bacteria.}, journal = {Toxicon : official journal of the International Society on Toxinology}, volume = {}, number = {}, pages = {107569}, doi = {10.1016/j.toxicon.2023.107569}, pmid = {38122835}, issn = {1879-3150}, abstract = {The present work addressed the abilities of two L-amino acid oxidases isolated from Bothrops moojeni (BmooLAAO-I) and Bothrops jararacussu (BjussuLAAO-II) snake venoms to control the growth and prevent the biofilm formation of clinically relevant bacterial pathogens. Upon S. aureus (ATCC BAA44) and S. aureus (clinical isolates), BmooLAAO-I (MIC = 0.12 and 0.24 μg/mL, respectively) and BjussuLAAO-II (MIC = 0.15 μg/mL) showed a potent bacteriostatic effect. Against E. coli (ATCC BAA198) and E. coli (clinical isolates), BmooLAAO-I (MIC = 15.6 and 62.5 μg/mL, respectively) and BjussuLAAO-II (MIC = 4.88 and 9.76 μg/mL, respectively) presented a lower extent effect. Also, BmooLAAO-I (MICB50 = 0.195 μg/mL) and BjussuLAAO-II (MICB50 = 0.39 μg/mL) inhibited the biofilm formation of S. aureus (clinical isolates) in 88% and 89%, respectively, and in 89% and 53% of E. coli (clinical isolates). Moreover, scanning electron microscopy confirmed that the toxins affected bacterial morphology by increasing the roughness of the cell surface and inhibited the biofilm formation. Furthermore, analysis of the tridimensional structures of the toxins showed that the surface-charge distribution presents a remarkable positive region close to the glycosylation motif, which is more pronounced in BmooLAAO-I than BjussuLAAO-II. This region may assist the interaction with bacterial and biofilm surfaces. Collectively, our findings propose that venom-derived antibiofilm agents are promising biotechnological tools which could provide novel strategies for biofilm-associated infections.}, } @article {pmid38118257, year = {2023}, author = {Pechaud, Y and Derlon, N and Queinnec, I and Bessiere, Y and Paul, E}, title = {Modelling biofilm development: The importance of considering the link between EPS distribution, detachment mechanisms and physical properties.}, journal = {Water research}, volume = {250}, number = {}, pages = {120985}, doi = {10.1016/j.watres.2023.120985}, pmid = {38118257}, issn = {1879-2448}, abstract = {In industry, treatments against biofilms need to be optimized and, in the wastewater treatment field, biofilm composition needs to be controlled. Therefore, describing the biochemical and physical structures of biofilms is now required to better understand the influence of operating parameters and treatment on biofilms. The present study aims to investigate how growth conditions influence EPS composition, biofilm physical properties and volume detachment using a 1D biofilm model. Two types of EPS are considered in the present model, proteins and polysaccharides. The main hypotheses are that: (i) the production of polysaccharides occurs mainly under strong nutrient limitation(s) while the production of proteins is coupled to both the substrate uptake rate and the lysis process; (ii) the local biofilm porosity depends on the local biofilm composition. Both volume and surface detachment occur in biofilms and volume detachment extent depends on the biofilm local cohesion and thus on the local composition of biofilms for a given shear stress. The model is based on experimental trends and aims to represent these observations on the basis of biochemical and physical processes. Four case studies covering a wide range of contrasting growth conditions such as different COD/N ratios, applied SOLR and shear stresses are investigated. The model predicts how the biochemical and physical biofilm structures change as a result of contrasting growth conditions. More precisely simulation results are in good agreement with the main experimental observations reported in the literature, such as: (i) a strong nitrogen limitation of growth induces an important accumulation of polysaccharides leading to a more porous and homogenous biofilm, (ii) a high applied surface organic loading load allows to obtain a high biofilm thickness, (iii) a strong shear stress applied during the biofilm growth leads to a reduction of the biofilm thickness and to a consolidation of the biofilm structure. Overall, this model represents a relevant decision tool for the selection of appropriate enzymatic treatments in the context of negative biofilm control. From our results, it appears that protease based treatments should be more appropriate for biofilms developed under low COD/N ratios (about 20 gCOD/gN) whereas both glucosidases and proteases based treatments should be more appropriate for biofilms developed under high COD/N ratio (about 70 gCOD/gN). In addition, the model could be useful for other applications such as resource recovery in biofilms or granules, and help to better understand biological membrane fouling.}, } @article {pmid38118251, year = {2023}, author = {Zheng, CW and Lai, YS and Luo, YH and Cai, Y and Wu, W and Rittmann, BE}, title = {A two-stage design enhanced biodegradation of high concentrations of a C16-alkyl quaternary ammonium compound in oxygen-based membrane biofilm reactors.}, journal = {Water research}, volume = {250}, number = {}, pages = {120963}, doi = {10.1016/j.watres.2023.120963}, pmid = {38118251}, issn = {1879-2448}, abstract = {Quaternary ammonia compounds (QAC), such as hexadecyltrimethyl-ammonium (CTAB), are widely used as disinfectants and in personal-care products. Their use as disinfectants grew during the SARS-CoV-2 (COVID-19) pandemic, leading to increased loads to wastewater treatment systems and the environment. Though low concentrations of CTAB are biodegradable, high concentrations are toxic to bacteria. Sufficient O2 delivery is a key to achieve high CTAB removal, and the O2-based Membrane Biofilm Reactor (O2-MBfR) is a proven means to biodegrade CTAB in a bubble-free, non-foaming manner. A strategy for achieving complete biodegradation of high-concentrations of CTAB is a two-stage O2-MBfR, in which partial CTAB removal in the Lead reactor relieves inhibition in the Lag reactor. Here, more than 98 % removal of 728 mg/L CTAB could be achieved in the two-stage MBfR, and the CTAB-removal rate was 70 % higher than for a one-stage MBfR with the same O2-delivery capacity. CTAB exposure shifted the bacterial community toward Pseudomonas and Stenotrophomonas as the dominant genera. In particular, P. alcaligenes and P. aeruginosa were enriched in the Lag reactor, as they were capable of biodegrading the metabolites of initial CTAB monooxygenation. Metagenomic analysis also revealed that the Lag reactor was enriched in genes for CTAB and metabolite oxygenation, due to reduced CTAB inhibition.}, } @article {pmid38117954, year = {2023}, author = {Pourmehdiabadi, A and Nobakht, MS and Hajjam Balajorshari, B and Yazdi, MR and Amini, K}, title = {Investigating the effects of zinc oxide and titanium dioxide nanoparticles on the formation of biofilm and persister cells in Klebsiella pneumoniae.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300454}, pmid = {38117954}, issn = {1521-4028}, abstract = {The biofilm formation in klebsiella pneumoniae isolates poses a significant problem as it can result in treatment failure and the development of chronic infections. These biofilms act as protective barriers, rendering the bacteria resistant to antibiotics. Additionally, persister cells, which make up a small fraction of the bacterial population, have the ability to enter a dormant state after treatment with high doses of antibiotics. These persister cells play a crucial role in the high level of biofilm-mediated tolerance to antibiotics. The present study aimed to investigate the impact of Zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles on the formation of biofilm and persister cells in K. pneumoniae. The minimum inhibitory concentration (MIC) of colistin in K. pneumoniae ATCC 13883 was determined using the microdilution method. The formation of persister cells was evaluated by introducing sub-MIC of colistin. Subsequently, the MIC of ZnO NPs and TiO2 NPs in these persister cells was assessed using the microdilution method. Furthermore, the effects of nanoparticles on the expression levels of biofilm-associated genes were analyzed using real-time polymer chain reaction (PCR). The MIC values for colistin, ZnO, and TiO2 were determined at 2, 12.5, and 6.25 μg/mL, respectively. In the presence of nanoparticles, biofilm formation decreased. Real-time PCR results showed the messenger RNA (mRNA) level of mrkH and fimH were decreased and the expression of luxS and mazF were increased. Biofilm formation of K. pneumoniae ATCC 1383 was inhibited in response to nanoparticles. According to the results of the present study use of nanoparticles may help control multidrug-resistant (MDR) infections in hospitalized patients.}, } @article {pmid38117082, year = {2023}, author = {Pugazhendhi, AS and Seal, A and Hughes, M and Kumar, U and Kolanthai, E and Wei, F and Schwartzman, JD and Coathup, MJ}, title = {Extracellular Proteins Isolated from L. acidophilus as an Osteomicrobiological Therapeutic Agent to Reduce Pathogenic Biofilm Formation, Regulate Chronic Inflammation, and Augment Bone Formation In Vitro.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2302835}, doi = {10.1002/adhm.202302835}, pmid = {38117082}, issn = {2192-2659}, abstract = {Periprosthetic joint infection (PJI) is a challenging complication that can occur following joint replacement surgery. Efficacious strategies to prevent and treat PJI and its recurrence remain elusive, and a novel resolution is urgently needed. Commensal bacteria within the gut microbiota convey beneficial effects by contributing to a defense strategy named "colonization resistance" thereby preventing pathogenic infection and overgrowth along the intestinal surface. This blueprint may be applicable to PJI. Here, the aim was to investigate Lactobacillus acidophilus spp. and primarily, isolated extracellular-derived L. acidophilus proteins (LaEPs) on PJI relevant S. aureus, MRSA, and E. coli planktonic growth and biofilm formation in vitro. The effect of LaEPs on cultured RAW264.7 macrophages and osteogenic, and adipogenic hBMSC differentiation was also analyzed. Data show electrostatically-induced probiotic-pathogen species co-aggregation and pathogenic growth inhibition together with LaEP-induced biofilm prevention. LaEPs activated macrophages priming them for enhanced microbial phagocytosis via cathepsin K, reduced lipopolysaccharide-induced DNA damage and RANKL expression, and promoted a reparative M2 macrophage morphology when under chronic inflammatory conditions. Our data also show LaEPs significantly augmented bone deposition while abating adipogenesis thus holding promise as a potential multimodal therapeutic strategy. Proteomic analyses highlight high abundance of lysyl endopeptidase, urocanate reductase, uridylate kinase, large ribosomal subunit protein bL12, and polyketide synthase. Further in vivo analyses are warranted to elucidate their role in the prevention and treatment of PJIs. This article is protected by copyright. All rights reserved.}, } @article {pmid38114754, year = {2023}, author = {Yadav, P and Goel, M and Gupta, RD}, title = {Anti-biofilm potential of human senescence marker protein 30 against Mycobacterium smegmatis.}, journal = {World journal of microbiology & biotechnology}, volume = {40}, number = {2}, pages = {45}, pmid = {38114754}, issn = {1573-0972}, support = {EMR/2016/007246//Science Engineering and Research Board, Government of India/ ; }, abstract = {Human senescence marker protein 30 (huSMP30) has been characterized as a multifaceted protein consisting of various enzymatic and cellular functions. It catalyzes the interconversion of L-gulonate and L-gulono-γ-lactone in the ascorbate biosynthesis pathway. Therefore, we hypothesized that it could be a potential anti-biofilm agent against pathogenic bacteria due to its lactonase activity. In order to corroborate this, the huSMP30 was recombinantly expressed, purified, and analyzed for its ability to inhibit Mycobacterium smegmatis biofilm formation, which showed a concentration-dependent inhibition as compared to the untreated control group. Further, in silico analysis was performed to redesign the huSMP30 with enhanced lactonase activity. Molecular docking analysis of the huSMP30 and lactone substrates facilitated the selection of three single amino acid substitutions (E18H, N154Q, and D204V), which were created using a PCR-based site-directed mutagenesis reaction. These mutant proteins and the wild-type huSMP30 were purified, and the effects on the enzymatic activity and biofilm formation were studied. The mutants E18H and D204V showed non-significant effects on specific lactonase activity, catalytic efficiency, and anti-biofilm property; however, the mutant N154Q showed significant improvement in the specific lactonase activity, catalytic efficiency, and inhibition in the biofilm formation. The protein stability analysis revealed that the wild-type huSMP30 and its designed mutants were stable at 37 °C for up to 4 days. In conclusion, the anti-biofilm property of the huSMP30 has been established, and an engineered version, N154Q, inhibits biofilm formation with greater efficiency. Human SMP30 is a versatile protein with multiple cellular and enzymatic functions, however, its anti-biofilm potential has not been explored. Our work presents the method to produce soluble and active huSMP30 in the E. coli expression system and establishes its role as an anti-biofilm agent against Mycobacterium smegmatis owing to its lactonase activity. Our results provide support for the future advancement of huSMP30 as a potential anti-biofilm agent targeting pathogenic Mycobacterium species.}, } @article {pmid38114092, year = {2023}, author = {Belkacem, N and Deghmane, AE and Taha, MK}, title = {Biofilm formation by non-typeable Haemophilus influenzae confers resistance to complement-mediated clearance.}, journal = {The Journal of infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1093/infdis/jiad584}, pmid = {38114092}, issn = {1537-6613}, abstract = {Biofilm formation is suggested to be associated with phenotype changes compared to planktonic form. We screened 1092 Haemophilus influenzae isolates for their genetic relationships and then selected 29 isolates from different genotypes and phenotypes and tested their ability to form biofilm. Our data showed a higher capacity of non-typeable isolates and particularly isolates from respiratory and genital infections to form biofilm compared to typeable isolates. This ability to form biofilm was also correlated with reduced deposition of the complement component C3b on biofilm-involved bacteria. These data suggest that the biofilm formation contributes to the virulence of non-typeable H. influenzae.}, } @article {pmid38113948, year = {2023}, author = {Chang, G and Yang, J and Li, X and Liao, H and Li, S and Hou, J and Zhong, G and Wang, J and Deng, M and Xue, Y}, title = {Iron-modified carriers accelerate biofilm formation and resist anammox bacteria loss in biofilm reactors for partial denitrification-anammox.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130223}, doi = {10.1016/j.biortech.2023.130223}, pmid = {38113948}, issn = {1873-2976}, abstract = {The slow formation of anammox biofilms presents a bottleneck for resolving anammox bacterial loss and achieving stable performance in biofilm-based partial denitrification-anammox (PD-A) processes. This study utilized iron-modified (K1/Fe3O4 NPs) carriers, which were prepared and used for the first time in PD-A processes. Parallel moving bed biofilm reactors (MBBRs) indicated that iron-modified carriers facilitated the formation of biofilms at a faster rate than K1 carriers, consequently improving the nitrogen removal performance of the process by over 40 %. 16S rDNA analysis showed that anammox bacteria were approximately four times more abundant in the iron-modified carrier biofilm than in the K1 carrier biofilm. XPS and zeta potential analysis suggested that the improved microbial affinity of the iron-modified carrier surface caused this. As a result, the iron-modified carriers facilitated the formation of anammox biofilms and enhanced PD-A performance.}, } @article {pmid38113787, year = {2023}, author = {Yang, Z and Shi, S and He, X and Cao, M and Lin, H and Fu, J and Zhou, J}, title = {High-efficient nutrient removal in a single-stage electrolysis-integrated sequencing batch biofilm reactor (E-SBBR) for low C/N sanitary sewage treatment.}, journal = {Journal of environmental management}, volume = {351}, number = {}, pages = {119848}, doi = {10.1016/j.jenvman.2023.119848}, pmid = {38113787}, issn = {1095-8630}, abstract = {To efficiently remove nutrients from low C/N sanitary sewage by conventional biological process is challenging due to the lack of sufficient electron donors. A novel electrolysis-integrated sequencing batch biofilm reactor (E-SBBR) was established to promote nitrogen and phosphorus removal for sanitary sewage with low C/N ratios (3.5-1.5). Highly efficient removal of nitrogen (>79%) and phosphorus (>97%) was achieved in the E-SBBR operating under alternating anoxic/electrolysis-anoxic/aerobic conditions. The coexistence of autotrophic nitrifiers, electron transfer-related bacteria, and heterotrophic and autohydrogenotrophic denitrifiers indicated synergistic nitrogen removal via multiple nitrogen-removing pathways. Electrolysis application induced microbial anoxic ammonia oxidation, autohydrogenotrophic denitrification and electrocoagulation processes. Deinococcus enriched on the electrodes were likely to mediate the electricity-driven ammonia oxidation which promoted ammonia removal. PICRUSt2 indicated that the relative abundances of key genes (hyaA and hyaB) associated with hydrogen oxidation significantly increased with the decreasing C/N ratios. The high autohydrogenotrophic denitrification rates during the electrolysis-anoxic period could compensate for the decreased heterotrophic rates resulting from insufficient carbon sources and nitrate removal was dramatically enhanced. Electrocoagulation with iron anode was responsible for phosphorus removal. This study provides insights into mechanisms by which electrochemically assisted biological systems enhance nutrient removal for low C/N sanitary sewage.}, } @article {pmid38113741, year = {2023}, author = {Zhang, B and Zhang, J and Wang, Y and Qu, J and Jiang, Z and Zhang, X and Tao, Y and Wang, Y and Kang, Z and Han, S and Zhang, J and Zhang, Y}, title = {Biodegradation of atrazine with biochar-mediated functional bacterial biofilm: Construction, characterization and mechanisms.}, journal = {Journal of hazardous materials}, volume = {465}, number = {}, pages = {133237}, doi = {10.1016/j.jhazmat.2023.133237}, pmid = {38113741}, issn = {1873-3336}, abstract = {The abuse and residue of herbicides in the black soil area had seriously affected the soil structure, function and crop growth, posing severe threats to agricultural soil environment and public health. Given the limitation of routine microbial remediation, innovative and eco-friendly functional bacterial biofilm which could adapt under adverse conditions was developed on the biochar to investigate its enhanced bioremediation and metabolic characteristics of typical herbicide atrazine. Results revealed that the atrazine degrading strain Acinetobacter lwoffii had competitive advantage in soil indigenous microorganisms and formed dense biofilms on the biochar which was beneficial to cell viability maintenance and aggregations. Metatranscriptomics and RT-qPCR analysis demonstrated that the biochar-mediated biofilm improved the frequency of intercellular communications through quorum sensing and two-component signal regulation systems, and enhanced the atrazine biodegradation efficiency through horizontal gene transfer in co-metabolism mode, providing important scientific basis for the biological remediation of farmland soil non-point source pollution.}, } @article {pmid38112469, year = {2023}, author = {Smiley, MK and Sekaran, DC and Forouhar, F and Wolin, E and Jovanovic, M and Price-Whelan, A and Dietrich, LEP}, title = {MpaR-driven expression of an orphan terminal oxidase subunit supports Pseudomonas aeruginosa biofilm respiration and development during cyanogenesis.}, journal = {mBio}, volume = {}, number = {}, pages = {e0292623}, doi = {10.1128/mbio.02926-23}, pmid = {38112469}, issn = {2150-7511}, abstract = {Cyanide is an inhibitor of heme-copper oxidases, which are required for aerobic respiration in all eukaryotes and many prokaryotes. This fast-acting poison can arise from diverse sources, but mechanisms by which bacteria sense it are poorly understood. We investigated the regulatory response to cyanide in the pathogenic bacterium Pseudomonas aeruginosa, which produces cyanide as a virulence factor. Although P. aeruginosa has the capacity to produce a cyanide-resistant oxidase, it relies primarily on heme-copper oxidases and even makes additional heme-copper oxidase proteins specifically under cyanide-producing conditions. We found that the protein MpaR controls expression of cyanide-inducible genes in P. aeruginosa and elucidated the molecular details of this regulation. MpaR contains a DNA-binding domain and a domain predicted to bind pyridoxal phosphate (vitamin B6), a compound that is known to react spontaneously with cyanide. These observations provide insight into the understudied phenomenon of cyanide-dependent regulation of gene expression in bacteria.}, } @article {pmid38108905, year = {2023}, author = {Ghosh, C and Das, MC and Acharjee, S and Bhattacharjee, S and Sandhu, P and Kumari, M and Bhowmik, J and Ghosh, R and Banerjee, B and De, UC and Akhter, Y and Bhattacharjee, S}, title = {Combating Staphylococcus aureus biofilm formation: the inhibitory potential of tormentic acid and 23-hydroxycorosolic acid.}, journal = {Archives of microbiology}, volume = {206}, number = {1}, pages = {25}, pmid = {38108905}, issn = {1432-072X}, mesh = {*Staphylococcus aureus ; *Triterpenes/pharmacology ; Bacterial Load ; Biofilms ; }, abstract = {Plant extracts have been used to treat microbiological diseases for centuries. This study examined plant triterpenoids tormentic acid (TA) and 23-hydroxycorosolic acid (HCA) for their antibiofilm effects on Staphylococcus aureus strains (MTCC-96 and MTCC-7405). Biofilms are bacterial colonies bound by a matrix of polysaccharides, proteins, and DNA, primarily impacting healthcare. As a result, ongoing research is being conducted worldwide to control and prevent biofilm formation. Our research showed that TA and HCA inhibit S. aureus planktonic growth by depolarizing the bacterial membrane. In addition, zone of inhibition studies confirmed their effectiveness, and crystal violet staining and biofilm protein quantification confirmed their ability to prevent biofilm formation. TA and HCA exhibited substantial reductions in biofilm formation for S. aureus (MTCC-96) by 54.85% and 48.6% and for S. aureus (MTCC-7405) by 47.07% and 56.01%, respectively. Exopolysaccharide levels in S. aureus biofilm reduced significantly by TA (25 μg/mL) and HCA (20 μg/mL). Microscopy, bacterial motility, and protease quantification studies revealed their ability to reduce motility and pathogenicity. Furthermore, TA and HCA treatment reduced the mRNA expression of S. aureus virulence genes. In silico analysis depicted a high binding affinity of triterpenoids for biofilm and quorum-sensing associated proteins in S. aureus, with TA having the strongest affinity for TarO (- 7.8 kcal/mol) and HCA for AgrA (- 7.6 kcal/mol). TA and HCA treatment reduced bacterial load in S. aureus-infected peritoneal macrophages and RAW264.7 cells. Our research indicates that TA and HCA can effectively combat S. aureus by inhibiting its growth and suppressing biofilm formation.}, } @article {pmid38108291, year = {2023}, author = {Zhou, Y and Wu, B and Cui, X and Ren, T and Ran, T and Rittmann, BE}, title = {Mass Flow and Metabolic Pathway of Nonaeration Greywater Treatment in an Oxygenic Microalgal-Bacterial Biofilm.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c06049}, pmid = {38108291}, issn = {1520-5851}, abstract = {A symbiotic microalgal-bacterial biofilm can enable efficient carbon (C) and nitrogen (N) removal during aeration-free wastewater treatment. However, the contributions of microalgae and bacteria to C and N removal remain unexplored. Here, we developed a baffled oxygenic microalgal-bacterial biofilm reactor (MBBfR) for the nonaerated treatment of greywater. A hydraulic retention time (HRT) of 6 h gave the highest biomass concentration and biofilm thickness as well as the maximum removal of chemical oxygen demand (94.8%), linear alkylbenzenesulfonates (LAS, 99.7%), and total nitrogen (97.4%). An HRT of 4 h caused a decline in all of the performance metrics due to LAS biotoxicity. Most of C (92.6%) and N (95.7%) removals were ultimately associated with newly synthesized biomass, with only minor fractions transformed into CO2 (2.2%) and N2 (1.7%) on the function of multifarious-related enzymes in the symbiotic biofilm. Specifically, microalgae photosynthesis contributed to the removal of C and N at 75.3 and 79.0%, respectively, which accounted for 17.3% (C) and 16.7% (N) by bacteria assimilation. Oxygen produced by microalgae favored the efficient organics mineralization and CO2 supply by bacteria. The symbiotic biofilm system achieved stable and efficient removal of C and N during greywater treatment, thus providing a novel technology to achieve low-energy-input wastewater treatment, reuse, and resource recovery.}, } @article {pmid38105253, year = {2023}, author = {Shaikh, S and Lapin, NA and Prasad, B and Sturge, CR and Pybus, C and Pifer, R and Wang, Q and Evers, BM and Chopra, R and Greenberg, DE}, title = {Intermittent alternating magnetic fields diminish metal-associated biofilm in vivo.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {22456}, pmid = {38105253}, issn = {2045-2322}, abstract = {Prosthetic joint infection (PJI) is a complication of arthroplasty that results in significant morbidity. The presence of biofilm makes treatment difficult, and removal of the prosthesis is frequently required. We have developed a non-invasive approach for biofilm eradication from metal implants using intermittent alternating magnetic fields (iAMF) to generate targeted heating at the implant surface. The goal of this study was to determine whether iAMF demonstrated efficacy in an in vivo implant biofilm infection model. iAMF combined with antibiotics led to enhanced reduction of biofilm on metallic implants in vivo compared to antibiotics or untreated control. iAMF-antibiotic combinations resulted in a > 1 - log further reduction in biofilm burden compared to antibiotics or iAMF alone. This combination effect was seen in both S. aureus and P. aeruginosa and seen with multiple antibiotics used to treat infections with these pathogens. In addition, efficacy was temperature dependent with increasing temperatures resulting in a greater reduction of biofilm. Tissue damage was limited (< 1 mm from implant-tissue interface). This non-invasive approach to eradicating biofilm could serve as a new paradigm in treating PJI.}, } @article {pmid38104733, year = {2023}, author = {Brindhadevi, K and Kim, PT and AlSalhi, MS and Elkader, OHA and T, N and Lee, J and Bharathi, D}, title = {Deciphering the photocatalytic degradation of polyaromatic hydrocarbons (PAHs) using hausmannite (Mn3O4) nanoparticles and their efficacy against bacterial biofilm.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140961}, doi = {10.1016/j.chemosphere.2023.140961}, pmid = {38104733}, issn = {1879-1298}, abstract = {Polyaromatic hydrocarbons (PAHs) are life-threatening organic pollutants that severely threaten ecosystems worldwide due to their poisonous qualities, cancer-causing properties, and mutation-causing qualities. Water and soil together form a critical component of the ecosystem that supports all life. Due to the pollutants that are being disposed of in them, their characteristics have changed, and their toxicity has increased. The goal of this study was to investigate the ability of hausmannite nanoparticles to degrade fluorene from soil and water. Using the chemical method, hausmannite nanoparticles were synthesized and further characterization was performed using UV-Vis, FTIR, DLS, XRD, and SEM-EDAX. Hausmannite significantly degraded fluorene using the batch adsorption method. The degradation was also confirmed by performing reactive kinetics using Freundlich's isotherm model and Langmuir's pseudo-second-order model of soil and water. In addition to the degradation efficacy, hausmannite was also proved to inhibit biofilm formation by Pseudomonas aeruginosa. The findings of the experiments confirmed the presence of hausmannite nanoparticles, as well as their physical properties, chemical properties, degradation properties, and parameters of the kinetic study. As a result, synthesized nanoparticles have been extensively utilized as a low-cost option for removing pollutants and microbial biofilm.}, } @article {pmid38103607, year = {2023}, author = {Manirakiza, B and Zhang, S and Addo, FG and Yu, M and Alklaf, SA}, title = {Interactions between water quality and microbes in epiphytic biofilm and superficial sediment of lake in trophic agriculture area.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {169321}, doi = {10.1016/j.scitotenv.2023.169321}, pmid = {38103607}, issn = {1879-1026}, abstract = {Epiphytic and superficial sediment biofilm-dwelling microbial communities play a pivotal role in water quality regulation and biogeochemical cycling in shallow lakes. However, the interactions are far from clear between water physicochemical parameters and microbial community on aquatic plants and in surface sediments of lake in trophic agriculture area. This study employed Illumina sequencing, Partial Least Squares Path Modeling (PLS-PM), and physico-chemical analytical methods to explore the interactions between water quality and microbes (bacteria and eukaryotes) in three substrates of trophic shallow Lake Cyohoha North, Rwanda. The Lake Cyohoha was significantly polluted with total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3-N), and ammonia nitrogen (NH3-N) in the wet season compared to the dry season. PLS-PM revealed a strong positive correlation (+0.9301) between land use types and physico-chemical variables in the rainy season. In three substrates of the trophic lake, Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were dominant phyla in the bacterial communities, and Rotifers, Platyhelminthes, Gastrotricha, and Ascomycota dominated in microeukaryotic communities. As revealed by null and neutral models, stochastic processes predominantly governed the assembly of bacterial and microeukaryotic communities in biofilms and surface sediments. Network analysis revealed that the microbial interconnections in Ceratophyllum demersum were more stable and complex compared to those in Eichhornia crassipes and sediments. Co-occurrence network analysis (|r| > 0.7, p < 0.05) revealed that there were complex interactions among physicochemical parameters and microbes in epiphytic and sediment biofilms, and many keystone microbes on three substrates played important role in nutrients removal, food web and microbial community stable. These findings emphasize that eutrophic water influence the structure, composition, and interactions of microbes in epiphytic and surface sediment biofilms, and provided new insights into the interconnections between water quality and microbial community in presentative substrates in tropical lacustrine ecosystems in agriculturally polluted areas. The study provides useful information for water quality protection and aquatic plants restoration for policy making and catchment management.}, } @article {pmid38102871, year = {2023}, author = {Anurag Anand, A and Amod, A and Anwar, S and Sahoo, AK and Sethi, G and Samanta, SK}, title = {A comprehensive guide on screening and selection of a suitable AMP against biofilm-forming bacteria.}, journal = {Critical reviews in microbiology}, volume = {}, number = {}, pages = {1-20}, doi = {10.1080/1040841X.2023.2293019}, pmid = {38102871}, issn = {1549-7828}, abstract = {Lately, antimicrobial resistance (AMR) is increasing at an exponential rate making it important to search alternatives to antibiotics in order to combat multi-drug resistant (MDR) bacterial infections. Out of the several antibacterial and antibiofilm strategies being tested, antimicrobial peptides (AMPs) have shown to give better hopes in terms of a long-lasting solution to the problem. To select a desired AMP, it is important to make right use of available tools and databases that aid in identification, classification, and analysis of the physiochemical properties of AMPs. To identify the targets of these AMPs, it becomes crucial to understand their mode-of-action. AMPs can also be used in combination with other antibacterial and antibiofilm agents so as to achieve enhanced efficacy against bacteria and their biofilms. Due to concerns regarding toxicity, stability, and bioavailability, strategizing drug formulation at an early-stage becomes crucial. Although there are few concerns regarding development of bacterial resistance to AMPs, the evolution of resistance to AMPs occurs extremely slowly. This comprehensive review gives a deep insight into the selection of the right AMP, deciding the right target and combination strategy along with the type of formulation needed, and the possible resistance that bacteria can develop to these AMPs.}, } @article {pmid38101188, year = {2023}, author = {Lake, FB and Chen, J and van Overbeek, LS and Baars, JJP and Abee, T and den Besten, HMW}, title = {Biofilm formation and desiccation survival of Listeria monocytogenes with microbiota on mushroom processing surfaces and the effect of cleaning and disinfection.}, journal = {International journal of food microbiology}, volume = {411}, number = {}, pages = {110509}, doi = {10.1016/j.ijfoodmicro.2023.110509}, pmid = {38101188}, issn = {1879-3460}, abstract = {Microbial multispecies communities consisting of background microbiota and Listeria monocytogenes could be established on materials used in food processing environments. The presence, abundance and diversity of the strains within these microbial multispecies communities may be affected by mutual interactions and differences in resistance towards regular cleaning and disinfection (C&D) procedures. Therefore, this study aimed to characterize the growth and diversity of a L. monocytogenes strain cocktail (n = 6) during biofilm formation on polyvinyl chloride (PVC) and stainless steel (SS) without and with the presence of a diverse set of background microbiota (n = 18). L. monocytogenes and background microbiota strains were isolated from mushroom processing environments and experiments were conducted in simulated mushroom processing environmental conditions using mushroom extract as growth medium and ambient temperature (20 °C) as culturing temperature. The L. monocytogenes strains applied during monospecies biofilm incubation formed biofilms on both PVC and SS coupons, and four cycles of C&D treatment were applied with a chlorinated alkaline cleaning agent and a disinfection agent based on peracetic acid and hydrogen peroxide. After each C&D treatment, the coupons were re-incubated for two days during an incubation period for 8 days in total, and C&D resulted in effective removal of biofilms from SS (reduction of 4.5 log CFU/cm[2] or less, resulting in counts below detection limit of 1.5 log CFU/cm[2] after every C&D treatment), while C&D treatments on biofilms formed on PVC resulted in limited reductions (reductions between 1.2 and 2.4 log CFU/cm[2], which equals a reduction of 93.7 % and 99.6 %, respectively). Incubation of the L. monocytogenes strains with the microbiota during multispecies biofilm incubation led to the establishment of L. monocytogenes in the biofilm after 48 h incubation with corresponding high L. monocytogenes strain diversity in the multispecies biofilm on SS and PVC. C&D treatments removed L. monocytogenes from multispecies biofilm communities on SS (reduction of 3.5 log CFU/cm[2] or less, resulting in counts below detection limit of 1.5 log CFU/cm[2] after every C&D treatment), with varying dominance of microbiota species during different C&D cycles. However, C&D treatments of multispecies biofilm on PVC resulted in lower reductions of L. monocytogenes (between 0.2 and 2.4 log CFU/cm[2]) compared to single species biofilm, and subsequent regrowth of L. monocytogenes and stable dominance of Enterobacteriaceae and Pseudomonas. In addition, planktonic cultures of L. monocytogenes were deposited and desiccated on dry surfaces without and with the presence of planktonic background microbiota cultures. The observed decline of desiccated cell counts over time was faster on SS compared to PVC. However, the application of C&D resulted in counts below the detection limit of 1.7 log CFU/coupon on both surfaces (reduction of 5.9 log CFU/coupon or less). This study shows that L. monocytogenes is able to form single and multispecies biofilms on PVC with high strain diversity following C&D treatments. This highlights the need to apply more stringent C&D regime treatments for especially PVC and similar surfaces to efficiently remove biofilm cells from food processing surfaces.}, } @article {pmid38100369, year = {2023}, author = {Wei, H and Yang, C and Bi, F and Li, B and Xie, R and Yu, D and Fang, S and Hua, Z and Wang, Q and Yang, G}, title = {Structure-Controllable and Mass-Produced Glycopolymersomes as a Template of the Carbohydrate@Ag Nanobiohybrid with Inherent Antibacteria and Biofilm Eradication.}, journal = {Biomacromolecules}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.biomac.3c01003}, pmid = {38100369}, issn = {1526-4602}, abstract = {Glycopolymer-supported silver nanoparticles (AgNPs) have demonstrated a promising alternative to antibiotics for the treatment of multidrug-resistant bacteria-infected diseases. In this contribution, we report a class of biohybrid glycopolymersome-supported AgNPs, which are capable of effectively killing multidrug-resistant bacteria and disrupting related biofilms. First of all, glycopolymersomes with controllable structures were massively fabricated through reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly (PISA) in an aqueous solution driven by complementary hydrogen bonding interaction between the pyridine and amide groups of N-(2-methylpyridine)-acrylamide (MPA) monomers. Subsequently, Ag[+] captured by glycopolymersomes through the coordination between pyridine-N and Ag[+] was reduced into AgNPs stabilized by glycopolymersomes upon addition of the NaBH4 reducing agent, leading to the formation of the glycopolymersome@AgNPs biohybrid. As a result, they showed a wide-spectrum and enhanced removal of multidrug-resistant bacteria and biofilms compared to naked AgNPs due to the easier adhesion onto the bacterial surface and diffusion into biofilms through the specific protein-carbohydrate recognition. Moreover, the in vivo results revealed that the obtained biohybrid glycopolymersomes not only demonstrated an effective treatment for inhibiting the cariogenic bacteria but also were able to repair the demineralization of caries via accumulating Ca[2+] through the recognition between carbohydrates and Ca[2+]. Furthermore, glycopolymersomes@AgNPs showed quite low in vitro hemolysis and cytotoxicity and almost negligible acute toxicity in vivo. Overall, this type of biohybrid glycopolymersome@AgNPs nanomaterial provides a new avenue for enhanced antibacterial and antibiofilm activities and the effective treatment of oral microbial-infected diseases.}, } @article {pmid38098364, year = {2023}, author = {Morgado, D and Fanesi, A and Martin, T and Tebbani, S and Bernard, O and Lopes, F}, title = {Exploring the dynamics of astaxanthin production in Haematococcus pluvialis biofilms using a rotating biofilm-based system.}, journal = {Biotechnology and bioengineering}, volume = {}, number = {}, pages = {}, doi = {10.1002/bit.28624}, pmid = {38098364}, issn = {1097-0290}, support = {955520//European Union's Horizon 2020 Research and Innovation Program/ ; }, abstract = {Microalgae biofilm emerged as a solid alternative to conventional suspended cultures which present high operative costs and complex harvesting processes. Among several designs, rotating biofilm-based systems stand out for their scalability, although their primary applications have been in wastewater treatment and aquaculture. In this work, a rotating system was utilized to produce a high-value compound (astaxanthin) using Haematococcus pluvialis biofilms. The effect of nitrogen regime, light intensity, and light history on biofilm traits was assessed to better understand how to efficiently operate the system. Our results show that H. pluvialis biofilms follow the classical growth stages described for bacterial biofilms (from adhesion to maturation) and that a two-stage (green and red stages) allowed to reach astaxanthin productivities of 204 mg m[-2] d[-1] . The higher light intensity applied during the red stage (400 and 800 µmol m[-2] s[-1]) combined with nitrogen depletion stimulated similar astaxanthin productivities. However, by training the biofilms during the green stage, using mild-light intensity (200 µmol m[-2] s[-1]), a process known as priming, the final astaxanthin productivity was enhanced by 40% with respect to biofilms pre-exposed to 50 µmol m[-2] s[-1] . Overall, this study shows the possibility of utilizing rotating microalgae biofilms to produce high-value compounds laying the foundation for further biotechnological applications of these emerging systems.}, } @article {pmid38098170, year = {2023}, author = {Wells, M and Mikesh, M and Gordon, V}, title = {Structure-preserving fixation allows Scanning Electron Microscopy to reveal biofilm microstructure and interactions with immune cells.}, journal = {Journal of microscopy}, volume = {}, number = {}, pages = {}, doi = {10.1111/jmi.13252}, pmid = {38098170}, issn = {1365-2818}, abstract = {{en} Pseudomonas aeruginosa is a pathogen that forms robust biofilms which are commonly associated with chronic infections and cannot be successfully cleared by the immune system. Neutrophils, the most common white blood cells, target infections with pathogen-killing mechanisms that are rendered largely ineffective by the protective physicochemical structure of a biofilm. Visualization of the complex interactions between immune cells and biofilms will advance understanding of how biofilms evade the immune system and could aid in developing treatment methods that promote immune clearance with minimal harm to the host. Scanning electron microscopy (SEM) distinguishes itself as a powerful, high-resolution tool for obtaining strikingly clear and detailed topographical images. However, taking full advantage of SEM's potential for high-resolution imaging requires that the fixation process simultaneously preserve both intricate biofilm architecture and the morphologies and structural signatures characterizing neutrophils responses at an infection site. Standard aldehyde-based fixation techniques result in significant loss of biofilm matrix material and morphologies of responding immune cells, thereby obscuring the details of immune interactions with the biofilm matrix. Here we show an improved fixation technique using the cationic dye alcian blue to preserve and visualize neutrophil interactions with the three-dimensional architecture of P. aeruginosa biofilms. We also demonstrate that this technique better preserves structures of biofilms grown from two other bacterial species, Klebsiella pneumoniae and Burkholderia thailandensis.{en} Pseudomonas aeruginosa is a species of bacteria that creates robust multicellular structures called biofilms. These biofilms often lead to long-lasting infections that the body's defense system struggles to eliminate. The most common white blood cells, called neutrophils, usually fight infections by attacking individual bacteria and eating them. However, the protective structure of biofilms makes immune cells much less effective at fighting bacteria. Understanding how biofilms evade the immune system is crucial for finding better ways to treat infections and reducing harm to the infected patient. Scanning electron microscopy (SEM) is a powerful tool for taking clear and detailed images. However, for SEM to work, the sample to be imaged has to undergo specialized preparation. Common methods to prepare samples for SEM result in the loss of important details of both the biofilm structure and the way neutrophils respond to infections. In this study, we present a method to prepare samples for SEM imaging that preserves much more of the biofilm and neutrophil structure than do usual methods. By preserving three-dimensional structure, this technique allows us to visualize much more clearly how neutrophils interact with P. aeruginosa biofilms. We also demonstrate that this technique better preserves structures of biofilms grown from two other bacterial species, Klebsiella pneumoniae and Burkholderia thailandensis.}, } @article {pmid38097907, year = {2023}, author = {Wang, X and Liu, M and Yu, C and Li, J and Zhou, X}, title = {Biofilm formation: mechanistic insights and therapeutic targets.}, journal = {Molecular biomedicine}, volume = {4}, number = {1}, pages = {49}, pmid = {38097907}, issn = {2662-8651}, support = {ZYYC21001//1·3·5 Project of Excellent Development of Discipline of West China Hospital of Sichuan University/ ; 2022SCUH0029//the "Zero to One" Innovation Research Project of Sichuan University/ ; 82072999 82273320//National Natural Science Foundation of China/ ; 82241049 81922042 82172285//National Natural Science Foundation of China/ ; }, abstract = {Biofilms are complex multicellular communities formed by bacteria, and their extracellular polymeric substances are observed as surface-attached or non-surface-attached aggregates. Many types of bacterial species found in living hosts or environments can form biofilms. These include pathogenic bacteria such as Pseudomonas, which can act as persistent infectious hosts and are responsible for a wide range of chronic diseases as well as the emergence of antibiotic resistance, thereby making them difficult to eliminate. Pseudomonas aeruginosa has emerged as a model organism for studying biofilm formation. In addition, other Pseudomonas utilize biofilm formation in plant colonization and environmental persistence. Biofilms are effective in aiding bacterial colonization, enhancing bacterial resistance to antimicrobial substances and host immune responses, and facilitating cell‒cell signalling exchanges between community bacteria. The lack of antibiotics targeting biofilms in the drug discovery process indicates the need to design new biofilm inhibitors as antimicrobial drugs using various strategies and targeting different stages of biofilm formation. Growing strategies that have been developed to combat biofilm formation include targeting bacterial enzymes, as well as those involved in the quorum sensing and adhesion pathways. In this review, with Pseudomonas as the primary subject of study, we review and discuss the mechanisms of bacterial biofilm formation and current therapeutic approaches, emphasizing the clinical issues associated with biofilm infections and focusing on current and emerging antibiotic biofilm strategies.}, } @article {pmid38097636, year = {2023}, author = {Klubthawee, N and Wongchai, M and Aunpad, R}, title = {The bactericidal and antibiofilm effects of a lysine-substituted hybrid peptide, CM-10K14K, on biofilm-forming Staphylococcus epidermidis.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {22262}, pmid = {38097636}, issn = {2045-2322}, support = {TUFT-FF34/2565//Thammasat University Research Fund/ ; }, abstract = {Staphylococci, notably biofilm-forming Staphylococcus epidermidis, have been recognized as global nosocomial pathogens in medical device-related infections. Their potential to attach to and form biofilm on indwelling catheters are significant factors impeding conventional treatment. Due to their extensive antimicrobial and antibiofilm actions, antimicrobial peptides (AMPs) have attracted interest as promising alternative compounds for curing difficult-to-treat, biofilm-forming bacterial infections. Cecropin A-melittin or CM, a well-known hybrid peptide, exhibits broad-spectrum antimicrobial activity, however it also possesses high toxicity. In the current study, a series of hybrid CM derivatives was designed using an amino acid substitution strategy to explore potential antibacterial and antibiofilm peptides with low toxicity. Among the derivatives, CM-10K14K showed the least hemolysis along with potent antibacterial activity against biofilm-forming S. epidermidis (MICs = 3.91 μg/mL) and rapid killing after 15 min exposure (MBCs = 7.81 μg/mL). It can prevent the formation of S. epidermidis biofilm and also exhibited a dose-dependent eradication activity on mature or established S. epidermidis biofilm. In addition, it decreased the development of biofilm by surviving bacteria, and formation of biofilm on the surface of CM-10K14K-impregnated catheters. Released CM-10K14K decreased planktonic bacterial growth and inhibited biofilm formation by S. epidermidis in a dose-dependent manner for 6 and 24 h post-exposure. Impregnation of CM-10K14K prevented bacterial attachment on catheters and thus decreased formation of extensive biofilms. SEM images supported the antibiofilm activity of CM-10K14K. Flow cytometry analysis and TEM images demonstrated a membrane-active mechanism of CM-10K14K, inducing depolarization and permeabilization, and subsequent membrane rupture leading to cell death. The presence of an interaction with bacterial DNA was verified by gel retardation assay. These antibacterial and antibiofilm activities of CM-10K14K suggest its potential application to urinary catheters for prevention of biofilm-forming colonization or for treatment of medical devices infected with S. epidermidis.}, } @article {pmid38097635, year = {2023}, author = {Ahmad, I and Nadeem, A and Mushtaq, F and Zlatkov, N and Shahzad, M and Zavialov, AV and Wai, SN and Uhlin, BE}, title = {Csu pili dependent biofilm formation and virulence of Acinetobacter baumannii.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {101}, pmid = {38097635}, issn = {2055-5008}, support = {2020-06136//Vetenskapsrådet (Swedish Research Council)/ ; 2022-04779//Vetenskapsrådet (Swedish Research Council)/ ; 2018-02914//Vetenskapsrådet (Swedish Research Council)/ ; 2019-01720//Vetenskapsrådet (Swedish Research Council)/ ; 8666/Punjab/NRPU/R&D/HEC/2017//Higher Education Commission, Pakistan (HEC)/ ; 2017-419//Cancerfonden (Swedish Cancer Society)/ ; SMK21-0076//Kempestiftelserna (Kempe Foundations)/ ; }, abstract = {Acinetobacter baumannii has emerged as one of the most common extensive drug-resistant nosocomial bacterial pathogens. Not only can the bacteria survive in hospital settings for long periods, but they are also able to resist adverse conditions. However, underlying regulatory mechanisms that allow A. baumannii to cope with these conditions and mediate its virulence are poorly understood. Here, we show that bi-stable expression of the Csu pili, along with the production of poly-N-acetyl glucosamine, regulates the formation of Mountain-like biofilm-patches on glass surfaces to protect bacteria from the bactericidal effect of colistin. Csu pilus assembly is found to be an essential component of mature biofilms formed on glass surfaces and of pellicles. By using several microscopic techniques, we show that clinical isolates of A. baumannii carrying abundant Csu pili mediate adherence to epithelial cells. In addition, Csu pili suppressed surface-associated motility but enhanced colonization of bacteria into the lungs, spleen, and liver in a mouse model of systemic infection. The screening of c-di-GMP metabolizing protein mutants of A. baumannii 17978 for the capability to adhere to epithelial cells led us to identify GGDEF/EAL protein AIS_2337, here denoted PdeB, as a major regulator of Csu pili-mediated virulence and biofilm formation. Moreover, PdeB was found to be involved in the type IV pili-regulated robustness of surface-associated motility. Our findings suggest that the Csu pilus is not only a functional component of mature A. baumannii biofilms but also a major virulence factor promoting the initiation of disease progression by mediating bacterial adherence to epithelial cells.}, } @article {pmid38097042, year = {2023}, author = {Sunnerhagen, T and Schwartz, F and Christophersen, L and Bjarnsholt, T and Qvortrup, K and Eldrup, N and Vogt, K and Moser, C}, title = {Corrigendum to 'Biofilm formation on endovascular aneurysm repair (EVAR) grafts-a proof of concept in vitro model'Clinical Microbiology and Infection (2023), Volume 29, Issue 12, P1600.e1-1600.e6.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cmi.2023.12.012}, pmid = {38097042}, issn = {1469-0691}, } @article {pmid38096935, year = {2023}, author = {Chen, P and Tian, J and Ren, Y and Cheng, H and Pan, H and Chen, S and Ye, X and Chen, J}, title = {Enhance the resistance of probiotics by microencapsulation and biofilm construction based on rhamnogalacturonan I rich pectin.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128777}, doi = {10.1016/j.ijbiomac.2023.128777}, pmid = {38096935}, issn = {1879-0003}, abstract = {Microcapsules were always used as functional material carriers for targeted delivery and meanwhile offering protection. However, microcapsule wall materials with specific properties were required, which makes the choice of wall material a key factor. In our previous study, a highly branched rhamnogalacturonan I rich (RG-I-rich) pectin was extracted from citrus canning processing water, which showed good gelling properties and binding ability, indicating it could be a potential microcapsule wall material. In the present study, Lactiplantibacillus plantarum GDMCC 1.140 and Lactobacillus rhamnosus were encapsulated by RG-I-rich pectin with embedding efficiencies of about 65 %. The environmental tolerance effect was evaluated under four different environmental stresses. Positive protection results were obtained under all four conditions, especially under H2O2 stress, the survival rate of probiotics embedded in microcapsules was about double that of free probiotics. The storage test showed that the total plate count of L. rhamnosus encapsulated in RG-I-rich pectin microcapsules could still reach 6.38 Log (CFU/mL) at 25 °C for 45 days. Moreover, probiotics embedded in microcapsules with additional incubation to form a biofilm layer inside could further improve the probiotics' activities significantly in the above experiments. In conclusion, RG-I-rich pectin may be a good microcapsule wall material for probiotics protection.}, } @article {pmid38095415, year = {2023}, author = {Bertrand, BP and Heim, CE and Koepsell, SA and Kielian, T}, title = {Elucidating granulocytic myeloid-derived suppressor cell heterogeneity during Staphylococcus aureus biofilm infection.}, journal = {Journal of leukocyte biology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jleuko/qiad158}, pmid = {38095415}, issn = {1938-3673}, abstract = {Myeloid-derived suppressor cells (MDSCs) are pathologically activated immature myeloid cells with immunosuppressive activity that expand during chronic inflammation, such as cancer and prosthetic joint infection (PJI). MDSCs can be broadly separated into two populations based on surface marker expression and function, namely monocytic MDSCs (M-MDSCs) and granulocytic MDSCs (G-MDSCs). G-MDSCs are the most abundant leukocyte infiltrate during PJI; however, how this population is maintained in vivo and cellular heterogeneity is currently unknown. In this study, we identified a previously unknown population of Ly6G + Ly6C + F4/80 + MHCII+ MDSCs during PJI that displayed immunosuppressive properties ex vivo. We leveraged F4/80 and MHCII expression by these cells for further characterization using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), which revealed a distinct transcriptomic signature of this population. F4/80 + MHCII+ MDSCs displayed gene signatures resembling G-MDSCs, neutrophils, and monocytes, but had significantly increased expression of pathways involved in cytokine response/production, inflammatory cell death, and mononuclear cell differentiation. To determine whether F4/80 + MHCII+ MDSCs represented an alternate phenotypic state of G-MDSCs, Ly6G + Ly6C + F4/80-MHCII- G-MDSCs from CD45.1 mice were adoptively transferred into CD45.2 recipients using a mouse model of PJI. A small percentage of transferred G-MDSCs acquired F4/80 and MHCII expression in vivo, suggesting some degree of plasticity in this population. Collectively, these results demonstrate a previously unappreciated phenotype of F4/80 + MHCII+ MDSCs during PJI, revealing that a granulocytic-to-monocytic transition can occur during biofilm infection.}, } @article {pmid38095263, year = {2023}, author = {Cao, Y and Cui, Z and Daigger, GT}, title = {Monitoring biofilm thickness using the membrane aerated biofilm reactor (MABR) fingerprint soft sensor to optimize nitrogen removal.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {95}, number = {12}, pages = {e10955}, doi = {10.1002/wer.10955}, pmid = {38095263}, issn = {1554-7531}, support = {//University of Michigan/ ; }, abstract = {The ongoing commercialization and installation of full-scale membrane aerated biofilm reactors (MABRs) stimulate the increasing need to monitor biofilm development. Biofilm thickness in MABRs can be assessed indirectly by plotting the exhaust oxygen purity versus bulk ammonia concentration, defined here as the MABR fingerprint soft sensor. Dynamic simulations with diurnal flow variations of an MABR unit model were implemented over a broad range of biofilm thicknesses and influent conditions consisting of variable C/N ratios and applied ammonia fluxes to assess the utility of the MABR fingerprint. Results show that the continuously decreasing trend of the MABR fingerprint plot slopes can be employed as a useful signal for biofilm thickness control in nitrogen removal processes. This technique is useful in a wide range of influent conditions and is helpful for MABR operators and designers to arrange biofilm thickness control events efficiently and determine where in an overall treatment process the technique can be applied to control biofilm thickness and optimize process performance. PRACTITIONER POINTS: The linear relationship between exhaust oxygen purity and bulk ammonia concentration is defined as the MABR fingerprint plot. MABR fingerprint plots are generated for a given biofilm thickness with diurnal flow or short-term loading variations implemented. Continuously decreasing trends of the MABR fingerprint plot slopes are useful signals for biofilm control in nitrogen removal. The MABR fingerprint is useful over a wide range of influent conditions regarding C/N ratios and applied ammonia fluxes. MABR practitioners can use the fingerprint plots to determine when biofilm control measures should be taken.}, } @article {pmid38093454, year = {2023}, author = {Ghosh, S and Sett, U and Pal, A and Nandy, S and Nandi, S and Chakrabarty, S and Das, A and Bandopadhyay, P and Basu, T}, title = {Anti-biofilm Potential of Nanonized Eugenol against Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad305}, pmid = {38093454}, issn = {1365-2672}, abstract = {AIMS: The purpose of this study was to synthesize a nanoform of eugenol (an important phytochemical with various pharmacological potentials) and to investigate its anti-biofilm efficacy on Pseudomonas aeruginosa biofilm.

METHODS AND RESULTS: Colloidal suspension of eugenol-nanoparticles (ENPs) was synthesized by the simple ultrasonic cavitation method through emulsification of hydrophobic eugenol into hydrophilic gelatin. Thus, the nanonization process made water-insoluble eugenol into water-soluble nano-eugenol, making the nano-form bioavailable. The size of the ENPs was 20-30 nm, entrapment efficiency of eugenol within gelatin was 80% and release of eugenol from gelatin cap was slow and sustained over five-days. Concerning the clinically relevant pathogen Pseudomonas aeruginosa, ENP had higher anti-biofilm (for both formation and eradication) activities than free eugenol. Minimal biofilm inhibitory concentration and minimal biofilm eradication concentration of ENP on P. aeruginosa biofilm were 2.0 and 4.0 mM respectively. In addition, the measurement of P. aeruginosa biofilm biomass, biofilm thickness, amount of biofilm extra-polymeric substance, cell surface hydrophobicity, cell swarming and twitching efficiencies, cellular morphology and biofilm formation in catheter demonstrated that the anti-biofilm efficacy of nano-eugenol was 30-40% higher than that of bulk eugenol.

CONCLUSION: These results signify that future pharmacological and clinical studies are very much required to investigate whether ENP can act as an effective drug against P. aeruginosa biofilm-mediated diseases. Thus, the problem of intrinsic antibiotics-tolerance of biofilm-forming cells may be minimized by ENP. Moreover, ENP may be used as a potential catheter-coating agent to inhibit pseudomonal colonization on catheter surfaces and therefore, to reduce catheter-associated infections and complications.}, } @article {pmid38092077, year = {2023}, author = {Liu, F and Xu, H and Shen, Y and Li, F and Yang, B}, title = {Rapid start-up strategy and microbial population evolution of anaerobic ammonia oxidation biofilm process for low-strength wastewater treatment.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130201}, doi = {10.1016/j.biortech.2023.130201}, pmid = {38092077}, issn = {1873-2976}, abstract = {The implementation of the anaerobic ammonium oxidation (anammox) process in treating low-strength wastewater is limited by the difficulty in enriching anammox bacteria (AnAOB). Here, the first enrichment of AnAOB at a high nitrogen (N) loading rate (NLR) as a strategy was proposed to achieve the rapid start-up of the anammox biofilm process treating low-strength wastewater. The long-term stability of the anammox biofilm process after start-up operating at a low NLR of 0.2-0.4 kg N/(m[3]⋅d) was evaluated. Results showed that the N removal efficiency was up to 75 % under a low NLR of 0.2 kg N/(m[3]⋅d) condition. Low-strength organic matter promoted the metabolic coupling between partial denitrifying bacteria (PDB) and AnAOB. The genus Candidatus Brocadia as AnAOB (18 %-27 %) can coexist with Limnobacter (PDB, 9 %-12 %) for efficient N removal. This study offers a rapid start-up strategy of anammox biofilm process in treating low-strength wastewater.}, } @article {pmid38091321, year = {2023}, author = {Ganser, C and Staples, MI and Dowell, M and Frazer, C and Dainis, J and Sircaik, S and Bennett, RJ}, title = {Filamentation and biofilm formation are regulated by the phase-separation capacity of network transcription factors in Candida albicans.}, journal = {PLoS pathogens}, volume = {19}, number = {12}, pages = {e1011833}, pmid = {38091321}, issn = {1553-7374}, abstract = {The ability of the fungus Candida albicans to filament and form biofilms contributes to its burden as a leading cause of hospital-acquired infections. Biofilm development involves an interconnected transcriptional regulatory network (TRN) consisting of nine transcription factors (TFs) that bind both to their own regulatory regions and to those of the other network TFs. Here, we show that seven of the nine TFs in the C. albicans biofilm network contain prion-like domains (PrLDs) that have been linked to the ability to form phase-separated condensates. Construction of PrLD mutants in four biofilm TFs reveals that these domains are essential for filamentation and biofilm formation in C. albicans. Moreover, biofilm PrLDs promote the formation of phase-separated condensates in the nuclei of live cells, and PrLD mutations that abolish phase separation (such as the removal of aromatic residues) also prevent biofilm formation. Biofilm TF condensates can selectively recruit other TFs through PrLD-PrLD interactions and can co-recruit RNA polymerase II, implicating condensate formation in the assembly of active transcriptional complexes. Finally, we show that PrLD mutations that block the phase separation of biofilm TFs also prevent filamentation in an in vivo model of gastrointestinal colonization. Together, these studies associate transcriptional condensates with the regulation of filamentation and biofilm formation in C. albicans, and highlight how targeting of PrLD-PrLD interactions could prevent pathogenesis by this species.}, } @article {pmid38091139, year = {2023}, author = {Nemchenko, UM and Voropaeva, NM and Sitnikova, KO and Belkova, NL and Savilov, ED}, title = {Testing a Method for Evaluation of the Viability of Biofilm-Forming Bacteria after Exposure to Disinfectants.}, journal = {Bulletin of experimental biology and medicine}, volume = {}, number = {}, pages = {}, pmid = {38091139}, issn = {1573-8221}, abstract = {A method for determining the viability of opportunistic pathogenic bacteria at the stage of biofilm formation after exposure to disinfectants with different active components was tested. The method is based on oxidation of tetrazolium salts by metabolically active cells with the formation of colored formazan derivatives and their quantitative spectrophotometry. The cell viability in the biofilm decreased after exposure to quaternary ammonium compounds and chlorine-containing disinfectants, but their effect was reversible. Dissemination of cells that had retained viability from the biofilm occurred after 24 h. The algorithm of testing, necessary controls, counting, and data interpretation are specified. The method can be recommended for use in laboratory diagnostics and clinical practice.}, } @article {pmid38088059, year = {2023}, author = {Wang, L and Zhang, C and Zhao, J and Zhu, Z and Wang, J and Fan, W and Jia, W}, title = {Biomimetic Targeting Nanoadjuvants for Sonodynamic And Chronological Multi-Immunotherapy Against Holistic Biofilm-Related Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2308110}, doi = {10.1002/adma.202308110}, pmid = {38088059}, issn = {1521-4095}, abstract = {Biofilm-related infections (BRIs) present significant challenges owing to drug resistance, adverse immune responses, and implant failure; however, current approaches inadequately cater to the diverse therapeutic requirements at different stages of infection. To address this issue, we proposed a multi-immunotherapy strategy in combination with sonodynamic therapy for the chronological treatment of BRIs. Macrophage membrane-decorated targeting sonosensitive nanoadjuvants were fabricated to load cytosine-phosphate-guanine oligodeoxynucleotide (CPG-ODN) or microRNA (miR)-21-5p. In the early stages of BRI (Stage I), CPG-ODN-loaded nanoadjuvants (CPG@HMPN@M) promoted the formation of neutrophil extracellular traps to capture and neutralize detached microbes. During the late stage of infection (Stage II), CPG-ODNs redirected macrophage polarization into the M1 phase to combat infections via TLR9/Myd88/TRAF6 pathway. During these stages, CPG@HMPN@M generated singlet oxygen through sonodynamic processes, eradicating the biofilms under US irradiation. Once the BRIs were eliminated, miR-21-5p-loaded nanoadjuvants (miR@HMPN@M) were delivered to the lesions to suppress excessive inflammation and promote tissue integration by evoking macrophage M2 polarization during the repair phase (Stage III) through PTEN/PI3K/Akt pathway. This innovative approach aimed to provide comprehensive treatment strategies for the chronological treatment of BRI by effectively eliminating infections, promoting tissue restoration, and implementing different immune regulations at different stages, thus demonstrating promising clinical value. This article is protected by copyright. All rights reserved.}, } @article {pmid38086612, year = {2023}, author = {Ren, S and Cheng, Y and Deng, Y and Xia, M and Yang, Y and Lei, L and Hu, T}, title = {Pudilan Keyanning mouthwash inhibits dextran-dependent aggregation and biofilm organization of Streptococcus mutans.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad298}, pmid = {38086612}, issn = {1365-2672}, abstract = {AIMS: This research aimed to investigate the inhibitory effects of Pudilan mouthwash (PDL) on Streptococcus mutans (S. mutans) biofilms and identify its chemical components.

METHODS AND RESULTS: The impacts of 100% concentrated PDL on S. mutans biofilm were detected by colony-forming unit (CFU) assays, crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and quantitative real-time PCR (qRT‒PCR). The biocompatibility with human gingival fibroblasts (HGFs) was evaluated by Cell-Counting-Kit-8 (CCK-8) assay. And chemical components were identified by UPLC-HRMS. PBS and 0.12% chlorhexidine were used as negative control and positive control, respectively. Results indicate early 8 h S. mutans biofilms are sensitive to PDL. Additionally, it leads to a decrease in bacterial activities and dextran-dependent aggregation in 24 h S. mutans biofilms. PDL significantly downregulates the gene expression of gtfB/C/D and smc. And 114 components are identified.

CONCLUSIONS: PDL has an inhibitory effect on S. mutans and favorable biocompatibility. It has potential to be exploited as a novel anti-biofilm agent.}, } @article {pmid38085930, year = {2023}, author = {Alsanea, A and Bounaga, A and Danouche, M and Lyamlouli, K and Zeroual, Y and Boulif, R and Zhou, C and Rittmann, B}, title = {Optimizing Autotrophic Sulfide Oxidation in the Oxygen-Based Membrane Biofilm Reactor to Recover Elemental Sulfur.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c05785}, pmid = {38085930}, issn = {1520-5851}, abstract = {Biological sulfide oxidation is an efficient means to recover elemental sulfur (S[0]) as a valuable resource from sulfide-bearing wastewater. This work evaluated the autotrophic sulfide oxidation to S[0] in the O2-based membrane biofilm reactor (O2-MBfR). High recovery of S[0] (80-90% of influent S) and high sulfide oxidation (∼100%) were simultaneously achieved when the ratio of O2-delivery capacity to sulfide-to S[0] surface loading (SL) (O2/S[2-] → S[0] ratio) was around 1.5 (g O2/m[2]-day/g O2/m[2]-day). On average, most of the produced S[0] was recovered in the MBfR effluent, although the biofilm could be a source or sink for S[0]. Shallow metagenomic analysis of the biofilm showed that the top sulfide-oxidizing genera present in all stages were Thauera, Thiomonas, Thauera_A, and Pseudomonas. Thiomonas or Pseudomonas was the most important genus in stages that produced almost only S[0] (i.e., the O2/S[2-] → S[0] ratio around 1.5 g of the O2/m[2]-day/g O2/m[2]-day). With a lower sulfide SL, the S[0]-producing genes were sqr and fccAB in Thiomonas. With a higher sulfide SL, the S[0]-producing genes were in the soxABDXYZ system in Pseudomonas. Thus, the biofilm community of the O2-MBfR adapted to different sulfide-to-S[0] SLs and corresponding O2-delivery capacities. The results illustrate the potential for S[0] recovery using the O2-MBfR.}, } @article {pmid38084141, year = {2023}, author = {Song, K and Chen, L and Suo, N and Kong, X and Li, J and Wang, T and Song, L and Cheng, M and Guo, X and Huang, Z and Huang, Z and Yang, Y and Tian, X and Choo, SW}, title = {Whole-transcriptome analysis reveals mechanisms underlying antibacterial activity and biofilm inhibition by a malic acid combination (MAC) in Pseudomonas aeruginosa.}, journal = {PeerJ}, volume = {11}, number = {}, pages = {e16476}, pmid = {38084141}, issn = {2167-8359}, abstract = {BACKGROUND: Pseudomonas aeruginosa is a highly prevalent bacterial species known for its ability to cause various infections and its remarkable adaptability and biofilm-forming capabilities. In earlier work, we conducted research involving the screening of 33 metabolites obtained from a commercial source against two prevalent bacterial strains, Escherichia coli and Staphylococcus aureus. Through screening assays, we discovered a novel malic acid combination (MAC) consisting of malic acid, citric acid, glycine, and hippuric acid, which displayed significant inhibitory effects. However, the precise underlying mechanism and the potential impact of the MAC on bacterial biofilm formation remain unknown and warrant further investigation.

METHODS: To determine the antibacterial effectiveness of the MAC against Pseudomonas aeruginosa, we conducted minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques were employed to observe bacterial morphology and biofilm formation. We further performed a biofilm inhibition assay to assess the effect of the MAC on biofilm formation. Whole-transcriptome sequencing and bioinformatics analysis were employed to elucidate the antibacterial mechanism of the MAC. Additionally, the expression levels of differentially expressed genes were validated using the real-time PCR approach.

RESULTS: Our findings demonstrated the antibacterial activity of the MAC against P. aeruginosa. SEM analysis revealed that the MAC can induce morphological changes in bacterial cells. The biofilm assay showed that the MAC could reduce biofilm formation. Whole-transcriptome analysis revealed 1093 differentially expressed genes consisting of 659 upregulated genes and 434 downregulated genes, in response to the MAC treatment. Mechanistically, the MAC inhibited P. aeruginosa growth by targeting metabolic processes, secretion system, signal transduction, and cell membrane functions, thereby potentially compromising the survival of this human pathogen. This study provides valuable insights into the antibacterial and antibiofilm activities of the MAC, a synergistic and cost-effective malic acid combination, which holds promise as a potential therapeutic drug cocktail for treating human infectious diseases in the future.}, } @article {pmid38083008, year = {2023}, author = {Preis, A and Grigull, RC and Wang, Y and Benke, E and Martin, S and Rieker, R and Franke, J and Reitelshofer, S}, title = {Pinch Valve Approach for a Biofilm Resistant Mechatronic Intraurethral Artificial Urinary Sphincter.}, journal = {Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference}, volume = {2023}, number = {}, pages = {1-4}, doi = {10.1109/EMBC40787.2023.10340925}, pmid = {38083008}, issn = {2694-0604}, abstract = {Stress urinary incontinence is the involuntary leakage of urine during increased abdominal pressure, such as coughing, sneezing, laughing, or exercising. It can have a significant negative impact on a person's quality of life and can result in decreased physical activity and social isolation. The presented closure mechanism for a mechatronic intraurethral artificial urinary sphincter is designed to be inserted minimally invasive into the urethra. The device consists of a solid shell, which serves as a housing for the electronics and is designed to enable fixation in the urethra. During micturition, the urine flows through the system, where it is guided through an elastic silicone-tube that, on the one hand, enables closure by a squeezing mechanism and, on the other hand, prevents biofilm growth by oscillation at a frequency of 22.5 Hz. The squeezing mechanism consists of a pinch valve system actuated by a piezo motor. The system has been tested under urodynamic conditions and the results show that it is able to close the urethra effectively to restore continence. The device is able to withstand sudden loads and shows good performance in terms of biofilm prevention during first experiments with artificial urine. The results show that the mechatronic intraurethral artificial urinary sphincter has the potential to be an effective and minimally invasive alternative to current treatment options for stress urinary incontinence.Clinical Relevance- This novel concept of a mechatronic intraurethral artificial urinary sphincter presents a promising alternative treatment option for patients suffering from stress urinary incontinence. As it is designed to be inserted minimally invasive, it reduces the impact and complications associated with current treatment options. The future development and testing of the device could lead to a safe and effective option for clinicians to offer their patients with stress urinary incontinence, which can improve their quality of life, and decrease costs for society and healthcare systems.}, } @article {pmid38081087, year = {2023}, author = {Fan, Y and Shi, K and Wang, C}, title = {Mathematical modeling and experimental validation of a novel Circulating Oxygenation Biofilm Equipment (COBE) for the management of decentralized wastewater treatment.}, journal = {Journal of environmental management}, volume = {351}, number = {}, pages = {119792}, doi = {10.1016/j.jenvman.2023.119792}, pmid = {38081087}, issn = {1095-8630}, abstract = {The difficulties of management were the key barriers to the promotion of decentralized wastewater treatment in remote areas. In this study, a novel decentralized Circulating Oxygenation Biofilm Equipment (COBE) and its remote management potential based on mathematical modeling were investigated. The COBE is an integrated biofilm reactor that employs drippage aeration and enables oxygenation, filtration, and effluent processes to be controlled, thus providing convenience for controlling. The model for the COBE describing drippage aeration, comprehensive ammonia-related microbes, and corncob carbon source release process was studied to uncover the impacts of operational conditions on decentralized wastewater treatment in the COBE system. The equipment regulation parameter (circulating oxygenation ratio) was found to be linearly correlated with the oxygen mass transfer coefficient. This discovery enabled highly accurate prediction of COD, NH4-N, and TN concentrations in the equipment effluent at various scenarios. The comprehensive ammonia oxidation biological model indicated that the model could duplicate the actual situation of the succession of ammonia metabolizing related microorganisms. Comammox and ammonia-oxidizing archaea (AOA) dominated ammonia metabolism in this equipment rather than conventional ammonium-oxidizing bacteria (AOB). This study could contribute to the Internet of Things system construction of decentralized wastewater treatment equipment, and provide a solution for timely decentralized equipment management in remote areas.}, } @article {pmid38078061, year = {2023}, author = {Høiby, N and Moser, C and Oliver, A and Williams, C and Ramage, G and Borghi, E and Azeredo, J and Macia, MD and , }, title = {To update or not to update the ESCMID guidelines for the diagnosis and treatment of biofilm infections - That is the question! The opinion of the ESGB board.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100135}, pmid = {38078061}, issn = {2590-2075}, abstract = {BACKGROUND: The work on the ESGB guidelines for diagnosis and treatment of biofilm infections began in 2012 and the result was published in 2014. The guidelines have been and still are frequently cited in the literature proving its usefulness for people working with biofilm infections. At the ESGB Biofilm conference in Mallorca 2022 (Eurobiofilms2022) the board of the ESGB decided to evaluate the 2014-guidelines and relevant publications since 2014 based on a lecture given at the Eurobiofilms2022.

GUIDELINE METHODS: The Delphi method for working on production of guidelines and the current ESCMID rules for guidelines are presented. The criteria for evaluation of relevant literature are very strict and especially for treatment, most clinicians and regulatory authorities require convincing results from Level I (randomized controlled trials) publications to justify changes of treatments. The relevant new biofilm literature and the relevant biofilm presentations from the Eurobiofilms meetings and ECCMID conferences was used for evaluating the contemporary relevance of the ESGB 2014 guidelines.

Several infectious diseases have been recognized as biofilm infections since 2014, but the diagnostic methods and therapeutic strategies are still the same as recommended in the 2014 ESGB guidelines which are summarized in this opinion paper.

Some promising new in vitro and in vivo (animal experiments) observations and reports for therapy of biofilm infections are mentioned, but they still await clinical trials.

CONCLUSION: The interim opinion at the present time (2022) is therefore, that the guidelines do not need revision now, but there is a need for survey articles discussing new methods of diagnosis and treatment of biofilm infections in order - hopefully - to give inspiration to conduct clinical trials which may lead to progress in diagnosis and treatment of patients with biofilm infections.}, } @article {pmid38078060, year = {2023}, author = {Shaw, JD and Bailey, TL and Ong, J and Brodke, DS and Williams, DL and Wawrose, RA and Epperson, RT and Kawaguchi, B and Ashton, NN}, title = {Development and validation of a large animal ovine model for implant-associated spine infection using biofilm based inocula.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100138}, pmid = {38078060}, issn = {2590-2075}, abstract = {Postoperative implant-associated spine infection remains poorly understood. Currently there is no large animal model using biofilm as initial inocula to study this challenging clinical entity. The purpose of the present study was to develop a sheep model for implant-associated spine infection using clinically relevant biofilm inocula and to assess the in vivo utility of methylene blue (MB) for visualizing infected tissues and guiding debridement. This 28-day study used five adult female Rambouillet sheep, each with two non-contiguous surgical sites- in the lumbar and thoracic regions- comprising randomized positive and negative infection control sites. A standard mini-open approach to the spine was performed to place sterile pedicle screws and Staphylococcus aureus biofilm-covered (positive control), or sterile (negative control) spinal fusion rods. Surgical site bioburden was quantified at the terminal procedure. Negative and positive control sites were stained with MB and staining intensity quantified from photographs. Specimens were analyzed with x-ray, micro-CT and histologically. Inoculation rods contained ∼10.44 log10 colony forming units per rod (CFU/rod). Biofilm inocula persisted on positive-control rod explants with ∼6.16 log10 CFU/rod. There was ∼6.35 log10 CFU/g of tissue in the positive controls versus no identifiable bioburden in the negative controls. Positive controls displayed hallmarks of deep spine infection and osteomyelitis, with robust local tissue response, bone resorption, and demineralization. MB staining was more intense in infected, positive control sites. This work presents an animal-efficient sheep model displaying clinically relevant implant-associated deep spine infection.}, } @article {pmid38078057, year = {2023}, author = {Espinosa-Ortiz, EJ and Gerlach, R and Peyton, BM and Roberson, L and Yeh, DH}, title = {Biofilm reactors for the treatment of used water in space:potential, challenges, and future perspectives.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100140}, pmid = {38078057}, issn = {2590-2075}, abstract = {Water is not only essential to sustain life on Earth, but also is a crucial resource for long-duration deep space exploration and habitation. Current systems in space rely on the resupply of water from Earth, however, as missions get longer and move farther away from Earth, resupply will no longer be a sustainable option. Thus, the development of regenerative reclamation water systems through which useable water can be recovered from "waste streams" (i.e., used waters) is sorely needed to further close the loop in space life support systems. This review presents the origin and characteristics of different used waters generated in space and discusses the intrinsic challenges of developing suitable technologies to treat such streams given the unique constrains of space exploration and habitation (e.g., different gravity conditions, size and weight limitations, compatibility with other systems, etc.). In this review, we discuss the potential use of biological systems, particularly biofilms, as possible alternatives or additions to current technologies for water reclamation and waste treatment in space. The fundamentals of biofilm reactors, their advantages and disadvantages, as well as different reactor configurations and their potential for use and challenges to be incorporated in self-sustaining and regenerative life support systems in long-duration space missions are also discussed. Furthermore, we discuss the possibility to recover value-added products (e.g., biomass, nutrients, water) from used waters and the opportunity to recycle and reuse such products as resources in other life support subsystems (e.g., habitation, waste, air, etc.).}, } @article {pmid38076077, year = {2023}, author = {Divakaran, D and Sriariyanun, M and Suyambulingam, I and Mavinkere Rangappa, S and Siengchin, S}, title = {Exfoliation and physico-chemical characterization of novel bioplasticizers from Nelumbo nucifera leaf for biofilm application.}, journal = {Heliyon}, volume = {9}, number = {12}, pages = {e22550}, pmid = {38076077}, issn = {2405-8440}, abstract = {Due to the extreme threats as environmental and health issues caused by the petroleum-based leachable plasticizers, researchers among different domains are more interested in finding unique biodegradable plasticizers from natural sources. The present study used Nelumbo nucifera leaf to extract novel biopolymers as viable substitutes for chemical plasticizers. The biopolymers extraction was carried out through chemical means and its physico-chemical and morphological characterization were carried out to confirm its plastic nature. The polymers extracted possess a low glass transition temperature (77.17 °C), good thermal stability (230 °C), low density (0.94 g/cc), good surface roughness (34.154 μm), low crystallinity index (25.1%) and moderate crystallite size (16.36 nm). The presence of an organic polymer with specific chemical groups as olefinic alkenes, epoxide, imino/azo groups, and hydrophobic organic siloxane groups, signify that the material is a condensed phenolic derivative. Furthermore, bio-film was formulated using NLP and poly lactic acid (PLA) matrix to evaluate its plasticizing effect and film-forming ability. Variation in specific properties of film was noted after bio-plasticizer addition, where tensile strength (20.94 ± 1.5 MPa to 19.22 ± 1.3 MPa) and Young's modulus (1.462 ± 0.43 GPa to 1.025 ± 0.52 GPa) was found to be decreased whereas increased the percentage of elongation at break (26.30 ± 1.1% to 39.64 ± 1.6%). In addition, decreased glass transition temperature (Tg) (59.17 °C), good surface compatibility, and increased flexibility of NLP-PLA film in contrast to pure PLA film authorizes the plasticizing effect of bio-plasticizers on PLA. Since the extracted bio-plasticizers could be a suitable replacement to harmful synthetic plasticizers for lightweight packaging applications in bioplastics sector.}, } @article {pmid38075881, year = {2023}, author = {Poscente, V and Di Gregorio, L and Costanzo, M and Nobili, C and Bernini, R and Garavaglia, L and Bevivino, A}, title = {Lactiplantibacillus plantarum monolayer enhanced bactericidal action of carvacrol: biofilm inhibition of viable foodborne pathogens and spoilage microorganisms.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1296608}, pmid = {38075881}, issn = {1664-302X}, abstract = {The prevalence of biofilm-associated microorganisms and the increasing use of ready-to-eat fresh products represent the current duality the food industry must address. Innovative and eco-friendly antibiofilm solutions and appropriate microbiological food control systems are urgently needed to improve food quality and safety. This study aimed to investigate the in vitro combined efficacy of carvacrol with a pre-formed biofilm monolayer of the probiotic Lactiplantibacillus plantarum DSM 20174. The antimicrobial activity of carvacrol against both planktonic and sessile cells of foodborne pathogens and spoilage microorganisms, alone or in the presence of the pre-formed biofilm of L. plantarum, was investigated by culture-based methods along with flow cytometry (FCM) to monitor cells' cultivability and viability. The synergistic action of carvacrol and the pre-formed biofilm of L. plantarum was evaluated in the 96-well plates. The results showed that L. plantarum pre-formed biofilm monolayer enhanced the antimicrobial effect of carvacrol determining a bactericidal action while the treatment alone induced the viable but not culturable (VBNC) cell state only. Furthermore, the great efficacy of the combined treatment allowed the application of a lower concentration of carvacrol (100 ppm) to achieve significant damage in cell viability. In conclusion, the incorporation of carvacrol into the L. plantarum pre-formed biofilm represents a promising alternative for an antimicrobial functionalized ready-to-eat packaging.}, } @article {pmid38075865, year = {2023}, author = {Wang, T and Zhang, R and Chen, Z and Cao, P and Zhou, Q and Wu, Q}, title = {A global bibliometric and visualized analysis of bacterial biofilm eradication from 2012 to 2022.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1287964}, pmid = {38075865}, issn = {1664-302X}, abstract = {BACKGROUND: To deeply explore the dynamic trends, focal points and emerging topics of bacterial biofilm eradication field and provide novel insights for prospective research endeavors, the first global bibliometric and visualized analysis of the field was employed in this study.

METHODS: The study meticulously curated articles and reviews concentrating on biofilm eradication from the Web of Science Core Collection (WoSCC) and identified literature published in 2012-2022 for further analysis, and the bibliometric and visualized analysis was performed to elucidate a clustering pattern in the domain with tools mainly including CiteSpace and VOSviewer.

RESULTS: 15,503 authors affiliated with 2,397 institutions spanning 96 countries or regions contributed to a corpus of 3,201 articles, containing 7,005 keywords. The USA emerged as a commanding vanguard in exploring the antibiofilm strategies and displaying pioneering initiatives within this sphere. The Chinese Academy of Sciences (CAS) emerged as the most prolific source of publications. Noteworthy among authors, Pandian Shunmugiah Karutha secured the lead in article contributions as well as co-citations while Deng Le with his team is poised to become a dominant influence in the future. Despite that, the extent of collaborative engagement across different institutions and authors appeared to fall short of its potential. Frontiers in Microbiology led the discourse by publishing a substantial body of articles and standing as the most recurrently co-cited publication. The most influential research domains encompassed "bacterial biofilm formation, "photodynamic therapy" and "phage therapy." Recent trends and forefronts concentrate on intensifying research into facilitating the shift of multiple strategies for biofilm eradication from controlled lab settings or animal studies to real-world clinical environments.

CONCLUSION: Fundamentally, this study presents a comprehensive scrutiny and reveals that the realm of bacterial biofilm eradication is undergoing rapid evolution, with even greater expansion anticipated in the times ahead. Subsequent scholars should emphasize the augmentation of collaborative efforts and focus their energies on emerging topics, thus contributing to break through current barriers in transitioning biofilm eradication strategies from the "fundamental" stage to "practical" application.}, } @article {pmid38072170, year = {2023}, author = {Kiarostami, K and Fernández-Barat, L and Battaglini, D and Motos, A and Bueno-Freire, L and Soler-Comas, A and Bassi, GL and Torres, A}, title = {The efficacy of telavancin in comparison with linezolid on endotracheal tube biofilm in pigs with methicillin-resistant Staphylococcus aureus pneumonia.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {107052}, doi = {10.1016/j.ijantimicag.2023.107052}, pmid = {38072170}, issn = {1872-7913}, abstract = {BACKGROUND: The effect of systemic treatment of ventilator-associated pneumonia (VAP) with telavancin, a semisynthetic lipoglycopeptide with good penetration in vitro biofilms, has not been tested in vivo during mechanical ventilation. This study examined the efficacy of telavancin compared with linezolid against endotracheal tube (ETT) biofilms in a porcine model of methicillin- resistant Staphylococcus aureus (MRSA) VAP.

METHODS: VAP was induced in 18 pigs by instilling 10[7] colony-forming units (CFU/mL) of a MRSA strain susceptible to telavancin and linezolid into each pulmonary lobe. Randomization into three groups was done at pneumonia diagnosis: control (IV glucose 0.5% solution q24); linezolid (10 mg/kg q12) and telavancin groups (22.5 mg/kg q24). After 72h of MV, data regarding bronchoalveolar lavage (BAL), tracheal aspirate (TA), ETT MRSA biofilm load and thickness measured by scanning electron microscopy were obtained.

RESULTS: All 18 pigs completed the study. MRSA was isolated in 100% of ETTs from the control and linezolid groups, and in 67% from the telavancin group. Telavancin treatment presented lower MRSA load compared to the control and linezolid treatments (telavancin median [interquartile range (IQR)] =1.94 [0.00-5.45], linezolid 3.99 [3.22-4.68] and control 4.93 [4.41-5.15], p=0.236). Telavancin treatment also resulted in the lowest biofilm thickness according to the SEM (4.04 [2.09-6.00], p<0.001). We found a positive correlation between ETT and BAL load (rho=0.511, p=0.045).

CONCLUSIONS: In our VAP model, systemic telavancin treatment reduced ETT MRSA occurrence, load, and biofilm thickness. Our findings may have a bearing on ICU patients' clinical outcomes.}, } @article {pmid38072080, year = {2023}, author = {Luan, YN and Yin, Y and Guo, Z and Yang, J and Wang, G and Zhang, F and Xiao, Y and Liu, C}, title = {Achieving simultaneous nitrification and endogenous denitrifying phosphorus removal in anaerobic/intermittently-aerated moving bed biofilm reactor for low carbon-to-nitrogen ratio wastewater treatment.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130178}, doi = {10.1016/j.biortech.2023.130178}, pmid = {38072080}, issn = {1873-2976}, abstract = {In this study, an anaerobic/intermittently-aerated moving bed biofilm reactor (AnIA-MBBR) was proposed to realize simultaneous nitrification and endogenous denitrifying phosphorus removal (SNEDPR) in treating low carbon-to-nitrogen (C/N) ratio wastewater. The effect of different intermittent aeration modes (short and long aeration) on nutrients' removal was investigated. With the C/N ratio around 3, the removal efficiencies of total nitrogen and phosphorus were 90% and 74%, 88% and 59%, respectively, for short aeration and long aeration. The different aeration time also altered the nutrients' degradation pathway, biofilm characteristics, microbial community, and functional metabolic pathways. The results confirmed the occurrence of aerobic denitrifiers, anoxic denitrifiers, phosphorus accumulating organisms, glycogen accumulating organisms in AnIA-MBBR systems and their synergistic performance induced the SNEDPR. These results indicated that the application of AnIA in MBBR systems was an effective strategy to achieve SNEDPR, providing better simultaneous removal performance of nitrogen and phosphorus from low C/N ratio wastewater.}, } @article {pmid38070800, year = {2023}, author = {Vohra, M and Kour, A and Kalia, NP and Kumar, M and Sharma, S and Jaglan, S and Kamath, N and Sharma, S}, title = {A comprehensive review of genomics, transcriptomics, proteomics, and metabolomic insights into the differentiation of Pseudomonas aeruginosa from the planktonic to biofilm state: A multi-omics approach.}, journal = {International journal of biological macromolecules}, volume = {257}, number = {Pt 1}, pages = {128563}, doi = {10.1016/j.ijbiomac.2023.128563}, pmid = {38070800}, issn = {1879-0003}, abstract = {Biofilm formation by Pseudomonas aeruginosa is primarily responsible for chronic wound and lung infections in humans. These infections are persistent owing to the biofilm's high tolerance to antimicrobials and constantly changing environmental factors. Understanding the mechanism governing biofilm formation can help to develop therapeutics explicitly directed against the molecular markers responsible for this process. After numerous years of research, many genes responsible for both in vitro and in vivo biofilm development remain unidentified. However, there is no "all in one" complete in vivo or in vitro biofilm model. Recent findings imply that the shift from planktonic bacteria to biofilms is a complicated and interrelated differentiation process. Research on the applications of omics technologies in P. aeruginosa biofilm development is ongoing, and these approaches hold great promise for expanding our knowledge of the mechanisms of biofilm formation. This review discusses the different factors that affect biofilm formation and compares P. aeruginosa biofilm formation using the omics approaches targeting essential biological macromolecules, such as DNA, RNA, Protein, and metabolome. Furthermore, we have outlined the application of currently available omics tools, such as genomics, proteomics, metabolomics, transcriptomics, and integrated multi-omics methodologies, to understand the differential gene expression (biofilm vs. planktonic bacteria) of P. aeruginosa biofilms.}, } @article {pmid38070765, year = {2023}, author = {Jung, H}, title = {A pore-scale reactive transport modeling study for quorum sensing-driven biofilm dispersal in heterogeneous porous media.}, journal = {Mathematical biosciences}, volume = {}, number = {}, pages = {109126}, doi = {10.1016/j.mbs.2023.109126}, pmid = {38070765}, issn = {1879-3134}, abstract = {Microorganisms regulate the expression of energetically expensive phenotypes via a collective decision-making mechanism known as quorum sensing (QS). This study investigates the intricate dynamics of biofilm growth and QS-controlled biofilm dispersal in heterogeneous porous media, employing a pore-scale reactive transport modeling approach. Model simulations carried out under various fluid flow conditions and biofilm growth scenarios reveal that QS processes are influenced not only by the biomass density of biofilm colonies but also by a complex interplay between pore architecture, flow velocity, and the rates of biofilm growth and dispersal. This study demonstrates that pore architecture controls the initiation of QS processes and advection gives rise to oscillatory growth of biofilms. Such oscillation is suppressed if biofilm dynamics are in favor of sustaining a sufficiently high signal concentration, such as fast growth or slow dispersal rates. By establishing a mathematical framework, this study contributes to the fundamental understanding of QS-controlled biofilm dynamics in natural porous media.}, } @article {pmid38069365, year = {2023}, author = {Campoccia, D and Ravaioli, S and Mirzaei, R and Bua, G and Daglia, M and Arciola, CR}, title = {Interactions of Neutrophils with the Polymeric Molecular Components of the Biofilm Matrix in the Context of Implant-Associated Bone and Joint Infections.}, journal = {International journal of molecular sciences}, volume = {24}, number = {23}, pages = {}, pmid = {38069365}, issn = {1422-0067}, support = {GAAC n. 730571. CUP: D39C20000130001.//Contribution from "5 per mille" of the Italian Ministry of Health to the Rizzoli Orthopaedic Institute of Bologna. WP "New nanostructured materials against the challenge of antibiotic resistance"./ ; }, abstract = {In the presence of orthopedic implants, opportunistic pathogens can easily colonize the biomaterial surfaces, forming protective biofilms. Life in biofilm is a central pathogenetic mechanism enabling bacteria to elude the host immune response and survive conventional medical treatments. The formation of mature biofilms is universally recognized as the main cause of septic prosthetic failures. Neutrophils are the first leukocytes to be recruited at the site of infection. They are highly efficient in detecting and killing planktonic bacteria. However, the interactions of these fundamental effector cells of the immune system with the biofilm matrix, which is the true interface of a biofilm with the host cells, have only recently started to be unveiled and are still to be fully understood. Biofilm matrix macromolecules consist of exopolysaccharides, proteins, lipids, teichoic acids, and the most recently described extracellular DNA. The latter can also be stolen from neutrophil extracellular traps (NETs) by bacteria, who use it to strengthen their biofilms. This paper aims to review the specific interactions that neutrophils develop when they physically encounter the matrix of a biofilm and come to interact with its polymeric molecular components.}, } @article {pmid38069351, year = {2023}, author = {Porzio, E and Andrenacci, D and Manco, G}, title = {Thermostable Lactonases Inhibit Pseudomonas aeruginosa Biofilm: Effect In Vitro and in Drosophila melanogaster Model of Chronic Infection.}, journal = {International journal of molecular sciences}, volume = {24}, number = {23}, pages = {}, pmid = {38069351}, issn = {1422-0067}, support = {PE13//PNRR/ ; FFC#10/2010//Cystic Fibrosis Research Foundation/ ; }, abstract = {Pseudomonas aeruginosa is one of the six antimicrobial-resistant pathogens known as "ESKAPE" that represent a global threat to human health and are considered priority targets for the development of novel antimicrobials and alternative therapeutics. The virulence of P. aeruginosa is regulated by a four-chemicals communication system termed quorum sensing (QS), and one main class of QS signals is termed acylhomoserine lactones (acyl-HSLs), which includes 3-Oxo-dodecanoil homoserine lactone (3-Oxo-C12-HSL), which regulates the expression of genes implicated in virulence and biofilm formation. Lactonases, like Paraoxonase 2 (PON2) from humans and the phosphotriesterase-like lactonases (PLLs) from thermostable microorganisms, are able to hydrolyze acyl-HSLs. In this work, we explored in vitro and in an animal model the effect of some lactonases on the production of Pseudomonas virulence factors. This study presents a model of chronic infection in which bacteria were administered by feeding, and Drosophila adults were treated with enzymes and the antibiotic tobramycin, alone or in combination. In vitro, we observed significant effects of lactonases on biofilm formation as well as effects on bacterial motility and the expression of virulence factors. The treatment in vivo by feeding with the lactonase SacPox allowed us to significantly increase the biocidal effect of tobramycin in chronic infection.}, } @article {pmid38069349, year = {2023}, author = {Zhu, X and Wang, A and Zheng, Y and Li, D and Wei, Y and Gan, M and Li, Y and Si, S}, title = {Anti-Biofilm Activity of Cocultimycin A against Candida albicans.}, journal = {International journal of molecular sciences}, volume = {24}, number = {23}, pages = {}, doi = {10.3390/ijms242317026}, pmid = {38069349}, issn = {1422-0067}, support = {82273830//National Natural Science Foundation of China/ ; 2021-I2M-1-070//CAMS Initiative for Innovative Medicine/ ; }, abstract = {Candida albicans (C. albicans), the most common fungal pathogen, has the ability to form a biofilm, leading to enhanced virulence and antibiotic resistance. Cocultimycin A, a novel antifungal antibiotic isolated from the co-culture of two marine fungi, exhibited a potent inhibitory effect on planktonic C. albicans cells. This study aimed to evaluate the anti-biofilm activity of cocultimycin A against C. albicans and explore its underlying mechanism. Crystal violet staining showed that cocultimycin A remarkably inhibited biofilm formation in a dose-dependent manner and disrupted mature biofilms at higher concentrations. However, the metabolic activity of mature biofilms treated with lower concentrations of cocultimycin A significantly decreased when using the XTT reduction method. Cocultimycin A could inhibit yeast-to-hypha transition and mycelium formation of C. albicans colonies, which was observed through the use of a light microscope. Scanning electron microscopy revealed that biofilms treated with cocultimycin A were disrupted, yeast cells increased, and hypha cells decreased and significantly shortened. The adhesive ability of C. albicans cells treated with cocultimycin A to the medium and HOEC cells significantly decreased. Through the use of a qRT-PCR assay, the expression of multiple genes related to adhesion, hyphal formation and cell membrane changes in relation to biofilm cells treated with cocultimycin A. All these results suggested that cocultimycin A may be considered a potential novel molecule for treating and preventing biofilm-related C. albicans infections.}, } @article {pmid38069139, year = {2023}, author = {Yang, Y and Chen, R and Rahman, MU and Wei, C and Fan, B}, title = {The sprT Gene of Bacillus velezensis FZB42 Is Involved in Biofilm Formation and Bacilysin Production.}, journal = {International journal of molecular sciences}, volume = {24}, number = {23}, pages = {}, doi = {10.3390/ijms242316815}, pmid = {38069139}, issn = {1422-0067}, support = {No. 31970097//National Natural Science Foundation of China/ ; }, abstract = {Bacillus velezensis FZB42, a representative strain of plant-growth-promoting rhizobacteria (PGPR), can form robust biofilm and produce multiple antibiotics against a wild range of phytopathogens. In this study, we observed different biofilm morphology of the mutant Y4, derived from a TnYLB-1 transposon insertion library of B. velezensis FZB42. We identified that the transposon was inserted into the sprT gene in Y4. Our bioinformatics analysis revealed that the SprT protein is an unstable hydrophilic protein located in the cytoplasm. It is highly conserved in Bacillus species and predicted to function as a metalloprotease by binding zinc ions. We also demonstrated that ΔsprT significantly reduced the swarming ability of FZB42 by ~5-fold and sporulation capacity by ~25-fold. In addition, the antagonistic experiments showed that, compared to the wild type, the ΔsprT strain exhibited significantly reduced inhibition against Staphylococcus aureus ATCC-9144 and Phytophthora sojae, indicating that the inactivation of sprT led to decreased production of the antibiotic bacilysin. The HPLC-MS analysis confirmed that bacilysin was indeed decreased in the ΔsprT strain, and qPCR analysis revealed that ΔsprT down-regulated the expression of the genes for bacilysin biosynthesis. Our results suggest that the sprT gene plays a regulatory role in multiple characteristics of B. velezensis FZB42, including biofilm formation, swarming, sporulation, and antibiotic production.}, } @article {pmid38068846, year = {2023}, author = {Klein, M and Al-Ahmad, A and Follo, M and Hellwig, E and Vach, K and Chrubasik-Hausmann, S}, title = {In Vitro Eradication of Planktonic, Saliva and Biofilm Bacteria Using Lingonberry Extract as a Photosensitizer for Visible Light Plus Water-Filtered Infrared-A Irradiation.}, journal = {Nutrients}, volume = {15}, number = {23}, pages = {}, doi = {10.3390/nu15234988}, pmid = {38068846}, issn = {2072-6643}, support = {AL 1179/4-1//Deutsche Forschungsgemeinschaft/ ; 2021/B3-Fol, 2023/A2-Fol//Medical Faculty, University of Freiburg/ ; }, abstract = {Antimicrobial photodynamic treatment (aPDT) with visible light plus water-filtered infrared-A irradiation (VIS-wIRA) and natural single- or multi-component photosensitizers (PSs) was shown to have potent antimicrobial activity. The aim of this study was to obtain information on the antimicrobial effects of aPDT-VIS-wIRA with lingonberry extract (LE) against bacteria that play a role in oral health. Planktonic bacterial cultures of the Gram-positive E. faecalis T9, S. mutans DSM20523, S. oralis ATCC 35037 and S. sobrinus PSM 203513, the Gram-negative N. oralis 14F2 FG-15-7B, F. nucleatum ATCC 25586, and V. parvula DSM, the anaerobic F. nucleatum ATCC 25586 and V. parvula DSM 2008, and the total mixed bacteria from pooled saliva and supra- and subgingival plaques of volunteers were all treated and compared. aPDT-VIS-wIRA with LE as PS significantly (p < 0.008) reduced the growth of all tested Gram-positive, Gram-negative, as well as aerobic and anaerobic bacterial strains, whereas without irradiation no reductions were seen (p < 0.0001). NaCl, with or without irradiation, was ineffective. After treatment with CHX 0.2%, the highest killing rate (100%) was observed, and no bacteria (0 log10 CFU) were cultivable. The method also significantly reduced all of the bacteria present in saliva and in the gingival biofilms. Three-dimensional visualization of viable and non-viable microorganisms revealed that LE penetrated deeper into the cell wall layers than CHX 0.2%. LE was an appropriate PS for eradicating microorganisms with VIS-wIRA, either in their planktonic form or in saliva and gingival plaque biofilms. These results encourage further investigation in order to determine which LE compounds contribute to the photosensitizing effect and to evaluate the size of the effect on maintaining oral health.}, } @article {pmid38068161, year = {2023}, author = {Anielak, AM and Polus, M and Diakun, H and Radomska-Kreft, I}, title = {The Importance of the Mineral Substrate of the Biofilm in the Process of Low-Temperature Removal of Nitrogen Compounds from Wastewater.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {23}, pages = {}, doi = {10.3390/ma16237417}, pmid = {38068161}, issn = {1996-1944}, support = {grant number POIR.04.01.04-00-0039/17//This research was funded by the National Center for Research and Development in Poland from EU funds,/ ; }, abstract = {This study researched the use of biofilms to remove nitrogen compounds from municipal sewages at low temperatures, especially in winter. An aluminosilicate substrate was used to create a biofilm, which has an affinity for ammonium ions. The selection of biofilm-forming microorganisms has been shown to occur on aluminosilicate. This substrate is mainly inhabited by microorganisms that remove nitrogen compounds. As a result, microorganisms protected against external factors in the biofilm effectively remove nitrogen compounds. The TN content in sewage treated at a temperature of 10 °C was of a 4 mg/L order and was 3-5 times lower than in the reference system (classical conditions). This process involves shortened nitrification/denitrification such as Anammox. As a result of a given process, CO2 emissions were reduced and much smaller amounts of NOx were produced, positively impacting the ongoing climate changes. Microbiological DNA/RNA tests have shown that the biofilm is primarily composed of archaea and bacteria that remove nitrogen compounds, including those that oxidize ammonia.}, } @article {pmid38067422, year = {2023}, author = {Noumi, E and Ahmad, I and Adnan, M and Patel, H and Merghni, A and Haddaji, N and Bouali, N and Alabbosh, KF and Kadri, A and Caputo, L and Polito, F and Snoussi, M and Feo, V}, title = {Illicium verum L. (Star Anise) Essential Oil: GC/MS Profile, Molecular Docking Study, In Silico ADME Profiling, Quorum Sensing, and Biofilm-Inhibiting Effect on Foodborne Bacteria.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {23}, pages = {}, doi = {10.3390/molecules28237691}, pmid = {38067422}, issn = {1420-3049}, support = {project number RG- 21 114.//Scientific Research Deanship at University of Ha'il - Saudi Arabia/ ; }, abstract = {Illicium verum, or star anise, has many uses ranging from culinary to religious. It has been used in the food industry since ancient times. The main purpose of this study was to determine the chemical composition, antibacterial, antibiofilm, and anti-quorum sensing activities of the essential oil (EO) obtained via hydro-distillation of the aerial parts of Illicium verum. Twenty-four components were identified representing 92.55% of the analyzed essential oil. (E)-anethole (83.68%), limonene (3.19%), and α-pinene (0.71%) were the main constituents of I. verum EO. The results show that the obtained EO was effective against eight bacterial strains to different degrees. Concerning the antibiofilm activity, trans-anethole was more effective against biofilm formation than the essential oil when tested using sub-inhibitory concentrations. The results of anti-swarming activity tested against P. aeruginosa PAO1 revealed that I. verum EO possesses more potent inhibitory effects on the swarming behavior of PAO1 when compared to trans-anethole, with the percentage reaching 38% at a concentration of 100 µg/mL. The ADME profiling of the identified phytocompounds confirmed their important pharmacokinetic and drug-likeness properties. The in silico study using a molecular docking approach revealed a high binding score between the identified compounds with known target enzymes involved in antibacterial and anti-quorum sensing (QS) activities. Overall, the obtained results suggest I. verum EO to be a potentially good antimicrobial agent to prevent food contamination with foodborne pathogenic bacteria.}, } @article {pmid38064903, year = {2023}, author = {Guo, Z and Qin, Y and Lv, J and Wang, X and Ye, T and Dong, X and Du, N and Zhang, T and Piao, F and Dong, H and Shen, S}, title = {High red/far-red ratio promotes root colonization of Serratia plymuthica A21-4 in tomato by root exudates-stimulated chemotaxis and biofilm formation.}, journal = {Plant physiology and biochemistry : PPB}, volume = {206}, number = {}, pages = {108245}, doi = {10.1016/j.plaphy.2023.108245}, pmid = {38064903}, issn = {1873-2690}, abstract = {Effective colonization on plant roots is a prerequisite for plant growth promoting rhizobacterias (PGPR) to exert beneficial activities. Light is essential for plant growth, development and stress response. However, how light modulates root colonization of PGPR remains unclear. Here, we found that high red/far red (R/FR) light promoted and low R/FR light inhibited the colonization and growth enhancement of Serratia plymuthica A21-4 (S. plymuthica A21-4) on tomato, respectively. Non-targeted metabolomic analysis of root exudates collected from different R/FR ratio treated tomato seedlings with or without S. plymuthica A21-4 inoculation by UPLC-MS/MS showed that 64 primary metabolites in high R/FR light-grown plants significantly increased compared with those determined for low R/FR light-grown plants. Among them, 7 amino acids, 1 organic acid and 1 sugar obviously induced the chemotaxis and biofilm formation of S. plymuthica A21-4 compared to the control. Furthermore, exogenous addition of five artificial root exudate compontents (leucine, methionine, glutamine, 6-aminocaproic acid and melezitose) regained and further increased the colonization ability and growth promoting ability of S. plymuthica A21-4 on tomato under low R/FR light and high R/FR light, respectively, indicating their involvement in high R/FR light-regulated the interaction of tomato root and S. plymuthica A21-4. Taken together, our results, for the first time, clearly demonstrate that high R/FR light-induced root exudates play a key role in chemotaxis, biofilm formation and root colonization of S. plymuthica A21-4. This study can help promote the combined application of light supplementation and PGPR to facilitate crop growth and health in green agricultural production.}, } @article {pmid38064782, year = {2023}, author = {Ke, Y and Sun, W and Chen, Z and Zhu, Y and Chen, X and Yan, S and Li, Y and Xie, S}, title = {Effects of disinfectant type and dosage on biofilm's activity, viability, microbiome and antibiotic resistome in bench-scale drinking water distribution systems.}, journal = {Water research}, volume = {249}, number = {}, pages = {120958}, doi = {10.1016/j.watres.2023.120958}, pmid = {38064782}, issn = {1879-2448}, abstract = {Drinking water distribution systems (DWDSs) are important for supplying high-quality water to consumers and disinfectant is widely used to control microbial regrowth in DWDSs. However, the disinfectant's influences on microbial community and antibiotic resistome in DWDS biofilms and the underlying mechanisms driving their dynamics remain elusive. The study investigated the effects of chlorine and chloramine disinfection on the microbiome and antibiotic resistome of biofilms in bench-scale DWDSs using metagenomics assembly. Additionally, the biofilm activity and viability were monitored based on adenosine triphosphate (ATP) and flow cytometer (FCM) staining. The results showed that both chlorine and chloramine disinfectants decreased biofilm ATP, although chloramine at a lower dosage (1 mg/L) could increase it. Chloramine caused a greater decrease in living cells than chlorine. Furthermore, the disinfectants significantly lowered the microbial community diversity and altered microbial community structure. Certain bacterial taxa were enriched, such as Mycobacterium, Sphingomonas, Sphingopyxis, Azospira, and Dechloromonas. Pseudomonas aeruginosa exhibited high resistance towards disinfectants. The disinfectants also decreased the complexity of microbial community networks. Some functional taxa (e.g., Nitrospira, Nitrobacter, Nitrosomonas) were identified as keystones in chloramine-treated DWDS microbial ecological networks. Stochasticity drove biofilm microbial community assembly, and disinfectants increased the contributions of stochastic processes. Chlorine had greater promotion effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and ARG hosts than chloramine. The disinfectants also selected pathogens, such as Acinetobacter baumannii and Klebsiella pneumonia, and these pathogens also harbored ARGs and MGEs. Overall, this study provides new insights into the effects of disinfectants on biofilm microbiome and antibiotic resistome, highlighting the importance of monitoring and managing disinfection practices in DWDSs.}, } @article {pmid38063945, year = {2023}, author = {Bicer, M}, title = {Exploring therapeutic avenues: mesenchymal stem/stromal cells and exosomes in confronting enigmatic biofilm-producing fungi.}, journal = {Archives of microbiology}, volume = {206}, number = {1}, pages = {11}, pmid = {38063945}, issn = {1432-072X}, abstract = {Fungal infections concomitant with biofilms can demonstrate an elevated capacity to withstand substantially higher concentrations of antifungal agents, contrasted with infectious diseases caused by planktonic cells. This inherent resilience intrinsic to biofilm-associated infections engenders a formidable impediment to effective therapeutic interventions. The different mechanisms that are associated with the intrinsic resistance of Candida species encompass drug sequestration by the matrix, drug efflux pumps, stress response cell density, and the presence of persister cells. These persisters, a subset of fungi capable of surviving hostile conditions, pose a remarkable challenge in clinical settings in virtue of their resistance to conventional antifungal therapies. Hence, an exigent imperative has arisen for the development of novel antifungal therapeutics with specific targeting capabilities focused on these pathogenic persisters. On a global scale, fungal persistence and their resistance within biofilms generate an urgent clinical need for investigating recently introduced therapeutic strategies. This review delves into the unique characteristics of Mesenchymal stem/stromal cells (MSCs) and their secreted exosomes, which notably exhibit immunomodulatory and regenerative properties. By comprehensively assessing the current literature and ongoing research in this field, this review sheds light on the plausible mechanisms by which MSCs and their exosomes can be harnessed to selectively target fungal persisters. Additionally, prospective approaches in the use of cell-based therapeutic modalities are examined, emphasizing the importance of further research to overcome the enigmatic fungal persistence.}, } @article {pmid38062650, year = {2023}, author = {Doğaç, Yİ and Tamfu, AN and Bozkurt, S and Kayhan, M and Teke, M and Ceylan, O}, title = {Inhibition of biofilm, quorum-sensing, and swarming motility in pathogenic bacteria by magnetite, manganese ferrite, and nickel ferrite nanoparticles.}, journal = {Biotechnology and applied biochemistry}, volume = {}, number = {}, pages = {}, doi = {10.1002/bab.2545}, pmid = {38062650}, issn = {1470-8744}, abstract = {Resistance to antibiotics by pathogenic bacteria constitutes a health burden and nanoparticles (NPs) are being developed as alternative and multipurpose antimicrobial substances. Magnetite (Fe3 O4 np), manganese ferrite (MnFe2 O4 np) and nickel ferrite (NiFe3 O4 np) NPs were synthesized and characterized using thermogravimetric analysis, transmission electron microscopy, Fourier transformed infra-red, and X-ray diffraction. The minimal inhibitory concentrations (MIC) ranged from 0.625 to 10 mg/mL against gram-positive (Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212), gram-negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and candida (Candida albicans ATCC 10239 and Candida tropicalis ATCC 13803) species. The NPs exhibited violacein inhibition against Chromobacterium violaceum CV12472 of 100% at MIC and reduced to 27.2% ± 0.8% for magnetite NPs, 12.7% ± 0.3% for manganese ferrite NPs and 43.1% ± 0.2% for nickel ferrite NPs at MIC/4. Quorum-sensing (QS) inhibition zones against C. violaceum CV026 were 12.5 ±0.6 mm for Fe3 O4 np, 09.1 ± 0.5 mm for MnFe3 O4 NP and 17.0 ± 1.2 mm for NiFe3 O4 np. The NPs inhibited swarming motility against P. aeruginosa PA01 and biofilm against six pathogens and the gram-positive biofilms were more susceptible than the gram-negative ones. The NiFe2 O4 np had highest antibiofilm activity against gram-positive and gram-negative bacteria as well as highest QS inhibition while Fe3 O4 NP had highest biofilm inhibition against candida species. The synthesized magnetic NPs can be used in developing anti-virulence drugs which reduce pathogenicity of bacteria as well as resistance.}, } @article {pmid38062568, year = {2023}, author = {Song, W and Zhang, S and Majzoub, ME and Egan, S and Kjelleberg, S and Thomas, T}, title = {The impact of interspecific competition on the genomic evolution of Phaeobacter inhibens and Pseudoalteromonas tunicata during biofilm growth.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16553}, pmid = {38062568}, issn = {1462-2920}, support = {//Australian Research Council/ ; //Singapore Centre for Environmental Life Sciences Engineering/ ; }, abstract = {Interspecific interactions in biofilms have been shown to cause the emergence of community-level properties. To understand the impact of interspecific competition on evolution, we deep-sequenced the dispersal population of mono- and co-culture biofilms of two antagonistic marine bacteria (Phaeobacter inhibens 2.10 and Pseudoalteromononas tunicata D2). Enhanced phenotypic and genomic diversification was observed in the P. tunicata D2 populations under both mono- and co-culture biofilms in comparison to P. inhibens 2.10. The genetic variation was exclusively due to single nucleotide variants and small deletions, and showed high variability between replicates, indicating their random emergence. Interspecific competition exerted an apparent strong positive selection on a subset of P. inhibens 2.10 genes (e.g., luxR, cobC, argH, and sinR) that could facilitate competition, while the P. tunicata D2 population was genetically constrained under competition conditions. In the absence of interspecific competition, the P. tunicata D2 replicate populations displayed high levels of mutations affecting the same genes involved in cell motility and biofilm formation. Our results show that interspecific biofilm competition has a complex impact on genomic diversification, which likely depends on the nature of the competing strains and their ability to generate genetic variants due to their genomic constraints.}, } @article {pmid38062361, year = {2023}, author = {Rahman, S and Das, AK}, title = {Staphylococcal superantigen-like protein 10 enhances the amyloidogenic biofilm formation in Staphylococcus aureus.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {390}, pmid = {38062361}, issn = {1471-2180}, support = {EMR/2016/002825//Science and Engineering Research Board/ ; EMR/2016/002825//Science and Engineering Research Board/ ; }, abstract = {Staphylococcus aureus is a highly infectious pathogen that represents a significant burden on the current healthcare system. Bacterial attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in chronic diseases such as endocarditis, osteomyelitis and wound infections. These biofilms decrease bacterial susceptibility to antibiotics and immune defences, making the infections challenging to treatment. S. aureus produces numerous exotoxins that contribute to the pathogenesis of the bacteria. In this study, we have identified a novel function of staphylococcal superantigen-like protein 10 (SSL10) in enhancing the formation of staphylococcal biofilms. Biofilm biomass is significantly increased when SSL10 is added exogenously to bacterial cultures, whereas SSL2 and SSL12 are found to be less active. Exogenously added SSL10 mask the surface charge of the bacterial cells and lowers their zeta potential, leading to the aggregation of the cells. Moreover, the biofilm formation by SSL10 is governed by amyloid aggregation, as evident from spectroscopic and microscopic studies. These findings thereby give the first overview of the SSL-mediated amyloid-based biofilm formation and further drive the future research in identifying potential molecules for developing new antibacterial therapies against Staphylococcus aureus.}, } @article {pmid38061667, year = {2023}, author = {Azrad, M and Abu-Rahmoun, L and Hamo, Z and Peretz, A}, title = {Associations of motility and auto-aggregation with biofilm-formation capacity levels in Clostridioidesdifficile.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106490}, doi = {10.1016/j.micpath.2023.106490}, pmid = {38061667}, issn = {1096-1208}, abstract = {Clostridioides difficile (C. difficile) is responsible for one of the most common nosocomial infections worldwide. This work assessed associations between biofilm-formation capacity levels of C. difficile and cell viability, motility, flagella, motility and auto-aggregation in 118 clinical isolates. Biofilm production was assessed by the crystal violet method. Cell viability was determined by BacTiter-Glo™ Microbial Cell Viability Assay and live-imaging microscopy. Expression levels of LuxS, Cwp84, Spo0A, PilA, and FliC were measured by real-time PCR. Motility was visually assessed in agar tubes. Auto-aggregation levels were determined by OD600 measurements. Out of 118 isolates, 66 (56 %) were biofilm producers, with most being strong or moderate producers. Cell viability, motility and auto-aggregation positively correlated with biofilm-production capacity (p = 0.0001, p = 0.036 and p < 0.0001, respectively). Positive associations were found between pilA, fliC and luxS expression levels and biofilm-production capacity (p = 0.04, p = 0.01, p = 0.036, respectively). This is the first report of associations between biofilm-formation capacity and cell viability, pilA, fliC, and luxS gene expression, auto-aggregation and motility. These correlations should be further explored to expand knowledge on the regulation of C. difficile biofilm formation, and pathogenesis, which will have notable implications on treatment options.}, } @article {pmid38059908, year = {2023}, author = {Papadopoulos, C and Larue, AE and Toulouze, C and Mokhtari, O and Lefort, J and Libert, E and Assémat, P and Swider, P and Malaquin, L and Davit, Y}, title = {A versatile micromodel technology to explore biofilm development in porous media flows.}, journal = {Lab on a chip}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3lc00293d}, pmid = {38059908}, issn = {1473-0189}, abstract = {Bacterial biofilms that grow in porous media are critical to ecosystem processes and applications ranging from soil bioremediation to bioreactors for treating wastewater or producing value-added products. However, understanding and engineering the complex phenomena that drive the development of biofilms in such systems remains a challenge. Here we present a novel micromodel technology to explore bacterial biofilm development in porous media flows. The technology consists of a set of modules that can be combined as required for any given experiment and conveniently tuned for specific requirements. The core module is a 3D-printed micromodel where biofilm is grown into a perfusable porous substrate. High-precision additive manufacturing, in particular stereolithography, is used to fabricate porous scaffolds with precisely controlled architectures integrating flow channels with diameters down to several hundreds of micrometers. The system is instrumented with: ultraviolet-C light-emitting diodes; on-line measurements of oxygen consumption and pressure drop across the porous medium; camera and spectrophotometric cells for the detection of biofilm detachment events at the outlet. We demonstrate how this technology can be used to study the development of Pseudomonas aeruginosa biofilm for several days within a network of flow channels. We find complex dynamics whereby oxygen consumption reaches a steady-state but not the pressure drop, which instead features a permanent regime with large fluctuations. We further use X-ray computed microtomography to image the spatial distribution of biofilms and computational fluid dynamics to link biofilm development with local flow properties. By combining the advantages of additive manufacturing for the creation of reproducible 3D porous microarchitectures with the flow control and instrumentation accuracy of microfluidics, our system provides a platform to study the dynamics of biofilm development in 3D porous media and to rapidly test new concepts in process engineering.}, } @article {pmid38059669, year = {2023}, author = {Sturabotti, E and Camilli, A and Moldoveanu, VG and Bonincontro, G and Simonetti, G and Valletta, A and Serangeli, I and Miranda, E and Amato, F and Marrani, AG and Migneco, LM and Sennato, S and Simonis, B and Vetica, F and Leonelli, F}, title = {Targeting the Antifungal Activity of Carbon Dots against Candida albicans Biofilm Formation by Tailoring Their Surface Functional Groups.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e202303631}, doi = {10.1002/chem.202303631}, pmid = {38059669}, issn = {1521-3765}, abstract = {Carbon dots (CDs) are an emerging class of carbon nanoparticles, which for their characteristics have found applications in many fields such as catalysis, materials and biomedicine. Within this context, the application of CDs as antibacterial agents has received much attention in very recent years, while their use as antifungal nanoparticles has been scarcely investigated. Here we report a systematic investigation of the surface functional groups of CDs to study their influence on these nanoparticles' against Candida albicans. Three classes of CDs have been synthesised and fully characterized. A thorough in vitro and in vivo biological screening against C. albicans was performed to test their antifungal, antiadhesion and antibiofilm formation activities. Moreover, the interaction with C. albicans cells was investigated by microscopic analysis. Our results evidence how the presence of a positively polarised surface results crucial for the internalization into COS-7 cells. Positively charged nanoparticles were also able to inhibit adhesion and biofilm formation, to interact with the cellular membrane of C. albicans, and to increase the survival of G. mellonella infected larvae after the injection with positive nanoparticles. The antifungal activity of CDs and their extremely low toxicity may represent a new strategy to combat infections sustained by C.albicans.}, } @article {pmid38059629, year = {2023}, author = {Campbell, MJ and Beenken, KE and Spencer, HJ and Jayana, B and Hester, H and Sahukhal, GS and Elasri, MO and Smeltzer, MS}, title = {Comparative evaluation of small molecules reported to be inhibitors of Staphylococcus aureus biofilm formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0314723}, doi = {10.1128/spectrum.03147-23}, pmid = {38059629}, issn = {2165-0497}, abstract = {Because biofilm formation is such a problematic feature of Staphylococcus aureus infections, much effort has been put into identifying biofilm inhibitors. However, the results observed with these compounds are often reported in isolation, and the methods used to assess biofilm formation vary between labs, making it impossible to assess relative efficacy and prioritize among these putative inhibitors for further study. The studies we report address this issue by directly comparing putative biofilm inhibitors using a consistent in vitro assay. This assay was previously shown to maximize biofilm formation, and the results observed with this assay have been proven to be relevant in vivo. Of the 19 compounds compared using this method, many had no impact on biofilm formation under these conditions. Indeed, only one proved effective at limiting biofilm formation without also inhibiting growth.}, } @article {pmid38057961, year = {2023}, author = {Almogbel, L and Zadeh, RS and Orgev, A and Çakmak, G and Li, R}, title = {Flexural strength, surface roughness, and biofilm formation of ceramic-reinforced PEEK: An in vitro comparative study.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {}, number = {}, pages = {}, doi = {10.1111/jopr.13815}, pmid = {38057961}, issn = {1532-849X}, abstract = {PURPOSE: This in vitro study aimed to compare flexural strength, surface roughness, and biofilm formation of ceramic-reinforced PEEK with conventionally heat-compressed and milled polymethylmethacrylate (PMMA) denture base materials.

METHODS: Thirty strips (6.4×10×3 mm) and 30 discs (10×1 mm) were fabricated from a heat-compressed PMMA, milled PMMA, and ceramic-reinforced PEEK, 10 each. One surface of each sample was polished to mimic the laboratory procedure for denture base materials. Strips were then subjected to a 3-point bend test using a universal testing machine at a crosshead speed of 5.0 mm/min. An optical profilometer was used to assess the Ra value (mm) of the discs on polished and unpolished sides. Biofilm formation behavior was analyzed by measuring the colony-forming unit (CFU)/ml of Candida albicans on the unpolished surface of the discs. One-way ANOVA followed by Tukey multiple comparison tests were used to compare the flexural strength, Ra value, and biofilm formation of the studied materials (a = 0.05).

RESULTS: Ceramic-reinforced PEEK showed significantly higher flexural strength (178.2 ±3.2 MPa) than milled PMMA (89.6 ±0.8 MPa; P<0.001) and heat-compressed PMMA (67.3 ±5.3 MPa; P<0.001). Ceramic-reinforced PEEK exhibited a significantly higher Ra value than the other groups on unpolished sides; however, the polishing process significantly reduced the Ra values of all studied groups (P<0.05). There was no significant difference in Candida albicans adhesion among the groups (P<0.05).

CONCLUSION: The flexural strength of tested materials was within acceptable limits for clinical use as a denture base material. Ceramic-reinforced PEEK had the highest surface roughness; however, its similarity in biofilm formation to other groups indicates its clinical acceptability as denture base material. This article is protected by copyright. All rights reserved.}, } @article {pmid38057457, year = {2023}, author = {Dixit, S and Varshney, S and Gupta, D and Sharma, S}, title = {Factors affecting biofilm formation by bacteria on fabrics.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {38057457}, issn = {1618-1905}, support = {PDF/2021/001456//Science and Engineering Research Board/ ; PDF/2021/001456//Science and Engineering Research Board/ ; }, abstract = {Fabrics act as fomites for microorganisms, thereby playing a significant role in infection transmission, especially in the healthcare and hospitality sectors. This study aimed to examine the biofilm formation ability of four nosocomial infection-causing bacteria (Acinetobacter calcoaceticus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) on cotton, polyester, polyester-cotton blend, silk, wool, viscose, and nylon, used frequently in the healthcare sector, by qualitative and quantitative methods. The impact of temperature, pH, and relative humidity (RH) on biofilm formation was also assessed. P. aeruginosa and S. aureus were strong biofilm producers, while E. coli produced weak biofilm. Wool (maximum roughness) showed the highest bacterial load, while silk (lowest roughness) showed the least. P. aeruginosa exhibited a higher load on all fabrics, than other test bacteria. Extracellular polymeric substances were characterized by infrared spectroscopy. Roughness of biofilms was assessed by atomic force microscopy. For biofilm formation, optimum temperature, pH, and RH were 30 °C, 7.0, and 62%, respectively. MgCl2 and CaCl2 were the most effective in removing bacterial biofilm. In conclusion, biofilm formation was observed to be influenced by the type of fabric, bacteria, and environmental conditions. Implementing recommended guidelines for the effective disinfection of fabrics is crucial to curb the risk of nosocomial infections. In addition, designing modified healthcare fabrics that inhibit pathogen load could be an effective method to mitigate the transmission of infections.}, } @article {pmid38054356, year = {2023}, author = {Peng, W and Li, L and Zhang, Y and Su, H and Jiang, X and Liu, H and Huang, X and Zhou, L and Shen, XC and Liu, C}, title = {Photothermal synergistic nitric oxide controlled release injectable self-healing adhesive hydrogel for biofilm eradication and wound healing.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb02040a}, pmid = {38054356}, issn = {2050-7518}, abstract = {The development of injectable self-healing adhesive hydrogel dressings with excellent bactericidal activity and wound healing ability is urgently in demand for combating biofilm infections. Herein, a multifunctional hydrogel (QP/QT-MB) with near-infrared (NIR) light-activated mild photothermal/gaseous antimicrobial activity was developed based on the dynamic reversible borate bonds and hydrogen bonds crosslinking between quaternization chitosan (QCS) derivatives alternatively containing phenylboronic acid and catechol-like moieties in conjunction with the in situ encapsulation of BNN6-loaded mesoporous polydopamine (MPDA@BNN6 NPs). Given the dynamic reversible cross-linking feature, the versatile hybrid hydrogel exhibited injectability, flexibility, and rapid self-healing ability. The numerous phenylboronic acid and catechol-like moieties on the QCS backbone confer the hydrogel with specific bacterial affinity, desirable tissue adhesion, and antioxidant stress ability that enhance bactericidal activity and facilitate the regeneration of infection wounds. Under NIR irradiation, the QP/QT-MB hydrogels exhibited a desirable mild photothermal effect and NIR-activity controllable NO delivery, combined with the endogenous contact antimicrobial activity of hydrogel, contributing jointly to induce dispersal of biofilms and disruption of the bacterial plasma membranes, ultimately leading to bacteria inactivation and biofilm elimination. In vivo experiments demonstrated that the fabricated QP/QT-MB hydrogel platform was capable of inducing efficient eradication of the S. aureus biofilm in a severely infected wound model and accelerating infected wound repair by promoting collagen deposition, angiogenesis, and suppressing inflammatory responses. Additionally, the QP/QT-MB hydrogel demonstrated excellent biocompatibility in vitro and in vivo. Collectively, the hydrogel (QP/QT-MB) reveals great potential application prospects as a promising alternative in the field of biofilm-associated infection treatment.}, } @article {pmid38051770, year = {2023}, author = {Torres-Sánchez, L and Géry Sana, T and Decossas, M and Hashem, Y and Krasteva, PV}, title = {Structures of the P. aeruginosa FleQ-FleN master regulators reveal large-scale conformational switching in motility and biofilm control.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {50}, pages = {e2312276120}, doi = {10.1073/pnas.2312276120}, pmid = {38051770}, issn = {1091-6490}, support = {757507 BioMatrix//EC | ERC | HORIZON EUROPE European Research Council (ERC)/ ; ExoPol//Université de Bordeaux (University of Bordeaux)/ ; }, abstract = {Pseudomonas aeruginosa can cause a wide array of chronic and acute infections associated with its ability to rapidly switch between planktonic, biofilm, and dispersed lifestyles, each with a specific arsenal for bacterial survival and virulence. At the cellular level, many of the physiological transitions are orchestrated by the intracellular second messenger c-di-GMP and its receptor-effector FleQ. A bacterial enhancer binding protein, FleQ acts as a master regulator of both flagellar motility and adherence factor secretion and uses remarkably different transcription activation mechanisms depending on its dinucleotide loading state, adenosine triphosphatase (ATPase) activity, interactions with polymerase sigma (σ) factors, and complexation with a second ATPase, FleN. How the FleQ-FleN tandem can exert diverse effects through recognition of a conserved FleQ binding consensus has remained enigmatic. Here, we provide cryogenic electron microscopy (cryo-EM) structures of both c-di-GMP-bound and c-di-GMP-free FleQ-FleN complexes which deepen our understanding of the proteins' (di)nucleotide-dependent conformational switching and fine-tuned roles in gene expression regulation.}, } @article {pmid38051365, year = {2023}, author = {Sil, M and Mukherjee, D and Goswami, A and Nag, M and Lahiri, D and Bhattacharya, D}, title = {Antibiofilm activity of mesoporous silica nanoparticles against the biofilm associated infections.}, journal = {Naunyn-Schmiedeberg's archives of pharmacology}, volume = {}, number = {}, pages = {}, pmid = {38051365}, issn = {1432-1912}, abstract = {In pharmaceutical industries, various chemical carriers are present which are used for drug delivery to the correct target sites. The most popular and upcoming drug delivery carriers are mesoporous silica nanoparticles (MSN). The main reason for its popularity is its ability to be specific and optimize the drug delivery process in a controlled manner. Nowadays, MSNs are widely used to eradicate various microbial infections, especially the ones related to biofilms. Biofilms are sessile groups of cells that live by forming a consortium and exhibit antibacterial resistance (AMR). They exhibit AMR by extracellular polymeric substances (EPS) and various quorum sensing (QS) signaling molecules. Usually, bacterial and fungal cells are capable of forming biofilms. These biofilms are pathogenic. In the majority of the cases, biofilms cause nosocomial diseases. This review will focus on the antibiofilm activities of MSN, its mechanism of target-specific drug delivery, and its ability to disrupt the bacterial biofilms inhibiting the infection. The review will also discuss various mechanisms for the delivery of pharmaceutical molecules by the MSNs to inhibit the bacterial biofilms, and lastly, we will talk about the different types of MSNs and their antibiofilm activities.}, } @article {pmid38050845, year = {2023}, author = {Rumbaugh, KP and Bjarnsholt, T}, title = {Microbial Primer: In vivo biofilm.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {12}, pages = {}, doi = {10.1099/mic.0.001407}, pmid = {38050845}, issn = {1465-2080}, abstract = {In this primer on biofilms and their role in infections, we trace the historical roots of microbial understanding from Van Leeuwenhoek's observations to Bill Costerton's groundbreaking work, which solidified biofilms' significance in infections. In vivo biofilm research, investigating patient samples and utilizing diverse host models, has yielded invaluable insights into these complex microbial communities. However, it comes with several challenges, particularly regarding replicating biofilm infections accurately in the laboratory. In vivo biofilm analyses involve various techniques, revealing biofilm architecture, composition, and behaviour, while gaps in knowledge persist regarding infection initiation and source, diversity, and the Infectious Microenvironment (IME). Ultimately, the study of biofilms in infections remains a dynamic and evolving field poised to transform our approach to combat biofilm-associated diseases.}, } @article {pmid38049472, year = {2023}, author = {Lee, J and Kim, YW}, title = {Bioelectric device for effective biofilm inflammation management of dental implants.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {21372}, pmid = {38049472}, issn = {2045-2322}, abstract = {Dental implant inflammation is primarily caused by oral biofilms, which form within 8 h, particularly at 37 °C, thereby requiring diligent cleaning. Considering the complex management of dental implants, a novel technology based on the bioelectric effect (BE) to combat inflammation has emerged. A BE-integrated toothbrush was developed and clinically tested on patients with dental implants (N = 36). Our findings revealed a significant average plaque index reduction of 67% with BE technology compared with that at baseline (P < 0.05), whereas non-BE did not yield statistical significance even after 4 weeks of use (P > 0.05). The bleeding index demonstrated a 59% average reduction in all surfaces with BE technology (P < 0.05), whereas the non-BE group exhibited no significant change. Substantial reductions in total plaque and bleeding indices suggest that using BE toothbrushes can help effectively remove oral biofilms and treat bleeding symptoms.}, } @article {pmid38049271, year = {2024}, author = {Lou, X and Wu, Y and Huang, Z and Zhang, W and Xiao, X and Wu, J and Li, J and Fang, Z}, title = {Biofilm formation and associated gene expression changes in Cronobacter from cereal related samples in China.}, journal = {Food microbiology}, volume = {118}, number = {}, pages = {104409}, doi = {10.1016/j.fm.2023.104409}, pmid = {38049271}, issn = {1095-9998}, abstract = {Cronobacter is an important foodborne pathogen that can cause severe neonatal meningitis, necrotizing enterocolitis, and bacteremia. Currently, there is limited knowledge of biofilm formation in Cronobacter. In the present study, biofilm formation ability and associated gene expression changes in Cronobacter from cereal related samples was carried out systematically. Our results from 307 Cronobacter isolates analyzed for 48 h showed strong biofilm-forming ability in 14 strains (4.6%), moderate in 47 strains (15.3%), weak in 142 strains (46.2%), and no such ability in the remaining 104 strains (33.9%). Further studies on five strains with strong biofilm-forming ability showed that maximum biofilm formation in Cronobacter occurred after 24 h of cultivation, reaching a peak around 48 h-72 h, reducing gradually thereafter. Kyoto encyclopedia of genes and genomes (KEGG) analysis revealed that differentially expressed genes (DEGs) involved in flagellar assembly, oxidative phosphorylation, ribosome, photosynthesis, O-Antigen nucleotide sugar biosynthesis, citrate cycle (tricarboxylic acid cycle, TCA) and bacterial chemotaxis were enriched in biofilm forming cells. The genes involved these enrichment pathways were mostly downregulated when compared to planktonic cells. Several transcriptional regulator genes such as csrA and bolA, and the cell surface composition regulator gene glgS were significantly upregulated. 12 of 13 (92.3%) selected genes was found to be in agreement with the RNA-Seq of planktonic and biofilm cells by Quantitative real-time PCR analysis, thus increasing confidence in our data. Our research lays a sound theoretical basis for further studies on mechanisms regulating biofilm formation and provides a foundation for development of new food safety measures, clinical disease prevention and control.}, } @article {pmid38049021, year = {2023}, author = {Cui, X and Liu, Y and Wei, T and Zhou, Y}, title = {Response of antibiotic resistance genes expression and distribution on extracellular polymeric substances and microbial community in membrane biofilm during greywater treatment.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130146}, doi = {10.1016/j.biortech.2023.130146}, pmid = {38049021}, issn = {1873-2976}, abstract = {This study evaluated how organic loading affects antibiotic resistance genes (ARGs) expression and distribution in the membrane biofilm. Organic surface loading rate of 4.65 g chemical oxygen demand (COD)/m[2]·d achieved the maximum biofilm thickness, concentration and linear alkylbenzene sulfonate (LAS) removal ratio of 136.9 ± 4.7 μm, 5.4 ± 0.1 g VSS/m[2] and 99.4 %, respectively. Extracellular polymeric substances (EPS), EPS-attached LAS, and ARGs gradually increased in the membrane air inlet, middle and air outlet. AGRs and Intl1 were abundant in biofilm. LAS promoted EPS secretion, biofilm growth and ARGs proliferation. EPS, protein and carbohydrate were significantly correlated with most of biofilm ARGs, but not corrected with liquid-based ARGs. Microbial community structure impacted ARGs proliferation and transfer in the system. The findings indicated that EPS and microbial community play a crucial role in ARGs proliferation, spread and distribution, which lay the foundation for front-end control of ARGs during biofilm-based wastewater treatment.}, } @article {pmid38048926, year = {2023}, author = {Jayakumar, J and Vinod, V and Arumugam, T and Sathy, BN and Biswas, L and Kumar, VA and Biswas, R}, title = {Efficacy of Lysostaphin functionalized silicon catheter for the prevention of Staphylococcus aureus biofilm.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128547}, doi = {10.1016/j.ijbiomac.2023.128547}, pmid = {38048926}, issn = {1879-0003}, abstract = {Staphylococcus aureus readily forms biofilms on tissue and indwelling catheter surfaces. These biofilms are resistant to antibiotics. Consequently, effective prevention and treatment strategies against staphylococcal biofilms are actively being pursued over the past two decades. One of the proposed strategies involve the incorporation of antibiotics and antiseptics into catheters, however, a persistent concern regarding the possible emergence of antimicrobial resistance is associated with these medical devices. In this study, we developed two types of silicone catheters: one with Lysostaphin (Lst) adsorbed onto the surface, and the other with Lst functionalized on the surface. To confirm the presence of Lst protein on the catheter surface, we conducted FTIR-ATR and SEM-EDS analysis. Both catheters exhibited hemocompatibility, biocompatibility, and demonstrated antimicrobial and biofilm prevention activities against both methicillin-sensitive and resistant strains of S. aureus. Furthermore, the silicone catheters that were surface-functionalized with Lst showed substantially better and more persistent anti-biofilm effects when compared to the catheters where Lst was surface-adsorbed, both under in vitro static and flow conditions, as well as in vivo in BALB/c mice. These results indicate that surface-functionalized Lst catheters have the potential to serve as a promising new medical device for preventing S. aureus biofilm infections in humans.}, } @article {pmid38048840, year = {2023}, author = {Barati, H and Fekrirad, Z and Jalali Nadoushan, M and Rasooli, I}, title = {Anti-OmpA antibodies as potential inhibitors of Acinetobacter baumannii biofilm formation, adherence to, and proliferation in A549 human alveolar epithelial cells.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106473}, doi = {10.1016/j.micpath.2023.106473}, pmid = {38048840}, issn = {1096-1208}, abstract = {Outer membrane protein A (OmpA) is a critical virulence factor in Acinetobacter baumannii, influencing adhesion, biofilm formation, host immune response, and host cell apoptosis. We investigated the invasion of A549 alveolar epithelial cells by A. baumannii and examined how anti-OmpA antibodies impact these interactions. OmpA was expressed and purified, inducing anti-OmpA antibodies in BALB/c mice. The potential toxicity of OmpA was evaluated in mice by analyzing histology from six organs. A549 cells were exposed to A. baumannii strains 19606 and a clinical isolate. Using cell culture and light microscopy, we scrutinized the effects of anti-OmpA sera on serum resistance, adherence, internalization, and proliferation of A. baumannii in A549 cells. The viability of A549 cells was assessed upon exposure to live A. baumannii and anti-OmpA sera. OmpA-induced antibody demonstrated potent bactericidal effects on both strains of A. baumannii. Both strains formed biofilms, which were reduced by anti-OmpA serum, along with decreased bacterial adherence, internalization, and proliferation in A549 cells. Anti-OmpA serum improved the survival of A549 cells post-infection. Pre-treatment with cytochalasin D hindered bacterial internalization, highlighting the role of actin polymerization in invasion. Microscopic examination revealed varied interactions encompassing adherence, apoptosis, membrane alterations, vacuolization, and damage. A549 cells treated with anti-OmpA serum exhibited improved structures and reduced damage. The findings indicate that A. baumannii can adhere to and proliferate within epithelial cells with OmpA playing a pivotal role in these interactions, and the complex nature of these interactions shapes the intricate course of A. baumannii infection in host cells.}, } @article {pmid38045711, year = {2023}, author = {Dalvand, M and Mirhosseini, SA and Amini, K and Khani, S and Mahmoodzadeh Hosseini, H and Mansoori, K}, title = {Evaluation of anti-biofilm activity of Lactobacillus rhamnosus GG and Nisin on the expression of aap, ica-A and ica-D as biofilm-associated genes of Staphylococcus epidermidis.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {4}, pages = {550-556}, pmid = {38045711}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: In the present study, the anti-biofilm activity of Lactobacillus rhamnosus GG and Nisin was investigated on biofilm-forming abilities of Staphylococcus epidermidis strains and the expression of the biofilm-associated genes.

MATERIALS AND METHODS: In this study, the standard strain of L. rhamnosus GG (ATCC 53103) and Nisin were used to assess their anti-microbial and anti-biofilm effects on S. epidermidis (RP62A).

RESULTS: The MIC and MBC analysis showed that Nisin at 256 μg/mL and 512 μg/mL, and L. rhamnosus GG at 1×10[7] CFU/mL and 1×10[8] CFU/mL have anti-microbial activity compared to the negative control respectively. L. rhamnosus GG bacteria and Nisin inhibited the biofilm formation of S. epidermidis based on optical density of at 570 nm (P <0.001). The relative mRNA expression of aap, icaA, and icaD genes was significantly reduced compared to the negative control after treating S. epidermidis with sub-MIC of Nisin (0.44, 0.25 and 0.6 fold, respectively) (P>0.05). In addition, the relative expression of aap and icaA genes, but not icaD (P>0.05), was significantly lower than the negative control (0.62 and 0.7 fold, respectively) (P>0.05), after exposure to the sub MIC of L. rhamnosus GG.

CONCLUSION: Nisin and L. rhamnosus GG exhibit potent activity against biofilm-forming abilities of S. epidermidis and these agents could be utilized as an anti-biofilm agents against S. epidermidis infections.}, } @article {pmid38045380, year = {2023}, author = {Karbelkar, AA and Font, ME and Smith, TJ and Sondermann, H and O'Toole, GA}, title = {Reconstitution of a Biofilm Adhesin System from a Sulfate-Reducing Bacterium in Pseudomonas fluorescens.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.11.22.568322}, pmid = {38045380}, abstract = {UNLABELLED: Biofilms of the sulfate reducing bacterium (SRB) Desulfovibrio vulgaris Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses; however, the mechanisms of biofilm formation by DvH are not yet well-understood. Evidence suggests that a large adhesin, DvhA, may be contributing to biofilm formation in DvH. The dvhA gene and its neighbors encode proteins that resemble the Lap system, which regulates biofilm formation by Pseudomonas fluorescens , including a LapG-like protease DvhG and effector protein DvhD, which has key differences from the previously described LapD. By expressing the Lap-like adhesion components of DvH in P. fluorescens , our data support the model that the N-terminal fragment of the large adhesin DvhA serves as an adhesin "retention module" and is the target of the DvhG/DvhD regulatory module, thereby controlling cell-surface location of the adhesin. By heterologously expressing the DvhG/DvhD-like proteins in a P. fluorescens background lacking native regulation (Δ lapG Δ lapD) we also show that cell surface regulation of the adhesin is dependent upon the intracellular levels of c-di-GMP. This study provides insight into the key players responsible for biofilm formation by DvH, thereby expanding our understanding of Lap-like systems.

SIGNIFICANCE: Corrosion leads to ∼2.5 trillion US dollars in economic losses, 20% of which are estimated to be microbially induced. Biofilms of sulfate reducing bacteria (SRB), especially the genus Desulfovibrio , are important members of the corrosion consortium and accelerate deterioration of metals. Understanding how biofilms are formed by SRB can provide important clues to mitigate this challenge. In this study, we used genetic and biochemical tools to investigate the mechanism of biofilm formation by Desulfovibrio vulgaris Hildenborough. Our study reveals critical genes responsible for regulating the secretion of a large adhesin known to be required for biofilm formation.}, } @article {pmid38043671, year = {2023}, author = {Aransiola, SA and Selvaraj, B and Maddela, NR}, title = {Bacterial biofilm formation and anti-biofilm strategies.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104172}, doi = {10.1016/j.resmic.2023.104172}, pmid = {38043671}, issn = {1769-7123}, } @article {pmid38043611, year = {2023}, author = {Wu, Z and Cao, X and Li, M and Liu, J and Li, B}, title = {Treatment of volatile organic compounds and other waste gases using membrane biofilm reactors: A review on recent advancements and challenges.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140843}, doi = {10.1016/j.chemosphere.2023.140843}, pmid = {38043611}, issn = {1879-1298}, abstract = {This article provides a comprehensive review of membrane biofilm reactors for waste gas (MBRWG) treatment, focusing on studies conducted since 2000. The first section discusses the membrane materials, structure, and mass transfer mechanism employed in MBRWG. The concept of a partial counter-diffusion biofilm in MBRWG is introduced, with identification of the most metabolically active region. Subsequently, the effectiveness of these biofilm reactors in treating single and mixed pollutants is examined. The phenomenon of membrane fouling in MBRWG is characterized, alongside an analysis of contributory factors. Furthermore, a comparison is made between membrane biofilm reactors and conventional biological treatment technologies, highlighting their respective advantages and disadvantages. It is evident that the treatment of hydrophobic gases and their resistance to volatility warrant further investigation. In addition, the emergence of the smart industry and its integration with other processes have opened up new opportunities for the utilization of MBRWG. Overcoming membrane fouling and developing stable and cost-effective membrane materials are essential factors for successful engineering applications of MBRWG. Moreover, it is worth exploring the mechanisms of co-metabolism in MBRWG and the potential for altering biofilm community structures.}, } @article {pmid38041064, year = {2023}, author = {Mohammadipour, HS and Tajzadeh, P and Atashparvar, M and Yeganehzad, S and Erfani, M and Akbarzadeh, F and Gholami, S}, title = {Formulation and antibacterial properties of lollipops containing of chitosan- zinc oxide nano particles on planktonic and biofilm forms of Streptococcus mutans and Lactobacillus acidophilus.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {957}, pmid = {38041064}, issn = {1472-6831}, abstract = {This study aimed to formulate and characterize the experimental lollipops containing chitosan- zinc oxide nanoparticles (CH-ZnO NPs) and investigate their antimicrobial effects against some cariogenic bacteria. The CH-ZnO NPs were synthesized and characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) analysis, and Transmission electron microscope (TEM). Then, four groups were made, including lollipops coated with 2 and 4 ml of CH-ZnO NPs, 0.7 ml CH-ZnO NPs incorporated lollipops, and those with no CH-ZnO NPs. Their antibacterial effectiveness against Streptococcus mutans and Lactobacillus acidophilus was evaluated by direct contact test and tissue culture plate method in planktonic and biofilm phases, respectively. Chlorhexidine mouthrinse (CHX) was used as a positive control group. In the planktonic phase, the antibacterial properties of both groups coated with CH-ZnO NPs were comparable and significantly higher than incorporated ones. There was no significant difference between CHX and the lollipops coated with 4 ml of NPs against S. mutans and CHX and two coated groups against L. acidophilus. None of the experimental lollipops in the biofilm phase could reduce both bacteria counts. The experimental lollipops coated with 2 and 4 ml of CH-ZnO NPs could reveal favorable antimicrobial properties against two cariogenic bacteria in the planktonic phase.}, } @article {pmid38040304, year = {2023}, author = {Abdelfattah, A and Eltawab, R and Iqbal Hossain, M and Zhou, X and Cheng, L}, title = {Membrane aerated biofilm reactor system driven by pure oxygen for wastewater treatment.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130130}, doi = {10.1016/j.biortech.2023.130130}, pmid = {38040304}, issn = {1873-2976}, abstract = {Pure oxygen is proposed for wastewater treatment due to its advantages over conventional air aeration. This study investigates a Pure Oxygen-based Membrane Aerated Biofilm Reactor (PO-MABR) for the first time under various operating conditions. The PO-MABR employs a gas-permeable membrane for direct diffusion of low-pressurized pure oxygen to the biofilm, ensuring exceptional carbon and nitrogen removal. The effectiveness of PO-MABR was investigated by varying operational conditions, including temperature, carbon-to-nitrogen ratio, gas pressure, and flow rate. Results indicate superior performance, with a 97% chemical oxygen demand removal and 19% higher total nitrogen removal than Air-Ventilated MABR (A-MABR) due to thicker biofilm and unique microbial structures in PO-MABR. Also, PO-MABR demonstrated resilience to low temperatures and effectively treated both high and low-strength wastewater. The findings emphasize the efficiency of PO-MABR in wastewater treatment, advocating for its adoption due to superior carbon and nitrogen removal across diverse operational conditions.}, } @article {pmid38039822, year = {2023}, author = {Hassani, M and Kamankesh, M and Rad-Malekshahi, M and Rostamizadeh, K and Rezaee, F and Haririan, I and Daghighi, SM}, title = {Biomaterials coated with zwitterionic polymer brush demonstrated significant resistance to bacterial adhesion and biofilm formation in comparison to brush coatings incorporated with antibiotics.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {234}, number = {}, pages = {113671}, doi = {10.1016/j.colsurfb.2023.113671}, pmid = {38039822}, issn = {1873-4367}, abstract = {A critical problem with the use of biomaterial implants is associated with bacterial adhesion on the surface of implants and in turn the biofilm formation. Among different strategies that have been reported to resolve this dilemma, surface design combined with both antiadhesive and antimicrobial properties has proven to be highly effective. Physiochemical properties of polymer brush coatings possess non-adhesive capability against bacterial adhesion and create a niche for further functionalization. The current study aims to evaluate the effect of antibiotics incorporated into the polymer brush on bacterial adhesion and biofilm formation. Brushes made of zwitterionic polymers were synthesized, functionalized with vancomycin via both physical and chemical conjugation, and grafted onto the silicon rubber surfaces. Antibacterial and antiadhesive measurements of designed coated biomaterials were mediated through the use of a parallel plate flow chamber against biofilm growth developed by Staphylococcus aureus and Escherichia coli over a period of 24 h. The analysis of biofilm growth on designed coated biomaterials showed that the pristine coated zwitterionic brushes are significantly resistant to bacterial adhesion and biofilm formation but not in the polymer brush coating incorporated with antibiotics.}, } @article {pmid38038143, year = {2023}, author = {Veiga, FF and Marcomini, EK and Salvador, A and Chiavelli, LUR and Barros, ILE and de Castro, LV and Lucca, DL and Ochikubo, LMK and Baesso, ML and Pomini, AM and Svidzinski, TIE and Negri, M}, title = {Detection of 2-ethyl-1-hexanol and its modulating effect in biofilm of Fusarium oxysporum.}, journal = {Molecular microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mmi.15194}, pmid = {38038143}, issn = {1365-2958}, support = {421620/2018-8//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Financier of Studies and Projects (FINEP/COMCAP)/ ; //Fundação de Amparo à Pesquisa do Estado do Paraná (Araucaria Foundation)/ ; }, abstract = {In immunocompetent individuals, Fusarium spp. stands out as the causative agent of onychomycosis, among the non-dermatophyte molds. Despite evidence indicating that Fusarium oxysporum organizes itself in the form of a biofilm causing onychomycosis, there is little literature on the etiopathogenesis of the biofilm on the nail, specifically the signaling molecules present, known as quorum sensing (QS). Thus, this study detected the presence of a molecule related to QS from the ex vivo biofilm of F. oxysporum on human nail and investigated its effect on preformed biofilm in vitro. The detection and physicochemical characterization of a QS molecule, from the extracellular matrix (ECM), was carried out by Fourier transform infrared (FTIR) spectroscopy with an attenuated total reflectance (ATR) accessory and by headspace gas chromatography coupled to mass spectrometry (GC-MS) analyses. Determination of viable cells, cell activity, total biomass, ECM components and scanning electron microscopy (SEM) were performed to evaluate the influence of the QS molecule on the in vitro biofilm of F. oxysporum. The beginning, in the ex vivo biofilm of F. oxysporum on human nails, the volatile organic compound 2-ethyl-1-hexanol (2EH) was detected as a component of QS. Thereafter in vitro analyses, synthetic 2EH was able to modulate the biofilm by stimulating its filament, increasing total biomass and ECM production in terms of total carbohydrates, but with a reduction in total proteins and nucleic acids. We thus evidence, for the first time, the presence of 2EH in the biofilm of F. oxysporum, developed on the human nail, and the in vitro action of this compound as a QS molecule.}, } @article {pmid38036851, year = {2023}, author = {Preziuso, S and Attili, AR and Cuteri, V}, title = {Methicillin-resistant staphylococci in clinical bovine mastitis: occurrence, molecular analysis, and biofilm production.}, journal = {Veterinary research communications}, volume = {}, number = {}, pages = {}, pmid = {38036851}, issn = {1573-7446}, abstract = {Staphylococcus aureus is an important pathogen that causes mastitis in cattle, and the emergence of methicillin-resistant S. aureus (MRSA) poses a threat to veterinary and human medicine. The aims of the study were to investigate the prevalence of MRSA and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from clinical mastitis, their ability to form biofilms, and the antimicrobial susceptibility of S. aureus strains. In addition, the Staphylococcal Cassette Chromosome mec (SCCmec) type, spa type and the presence of Panton-Valentine Leucocidin in MRSA were evaluated. A total of 326 staphylococcal strains were screened by multiplex-PCR for S. aureus and Staphylococcus intermedius group (SIG) identification. The S. aureus strains (n = 163) were subjected to phenotypic testing for antimicrobial susceptibility and biofilm formation. Molecular analysis was performed on MRSA mecA-positive strains. Of 163 S. aureus isolates, 142 strains (87.1%) were resistant to at least one antibiotic, and all 19 MRSA strains were resistant to at least four out of five antibiotics tested. All S. aureus strains harboured the icaA gene and were biofilm producers. Nineteen MR-CoNS strains were also isolated. The most prevalent spa types among MRSA were t001 (57.9%) and t037 (31.6%), while one MRSA was type t008 and one was type t041. Most MRSA were SCCmec type I (63.2%) and III (31.6%) and only one strain was type IV. None of the MRSA isolates had the PVL gene. The prevalence of multidrug-resistant S. aureus in bovine mastitis is a serious concern. The finding of MRSA with spa types predominant in humans and infrequent in Italian cows and with SCCmec infrequently found in bovine milk or cheese suggest a human origin of these strains. The ability of MRSA and MR-CoNS involved in bovine mastitis to be transferred to humans and vice versa poses a public health concern.}, } @article {pmid38035931, year = {2023}, author = {Zhou, W and Niu, D and Gao, S and Zhong, Q and Liu, C and Liao, X and Cao, X and Zhang, Z and Zhang, Y and Shen, H}, title = {Erratum to 'Prevalence, biofilm formation, and mass spectrometric characterization of linezolid-resistant Staphylococcus capitis isolated from a tertiary hospital in China' [Journal of Global Antimicrobial Resistance 33 (2023) 155-163].}, journal = {Journal of global antimicrobial resistance}, volume = {35}, number = {}, pages = {358}, doi = {10.1016/j.jgar.2023.05.005}, pmid = {38035931}, issn = {2213-7173}, } @article {pmid38035713, year = {2023}, author = {Guo, G and Liu, Z and Yu, J and You, Y and Li, M and Wang, B and Tang, J and Han, P and Wu, J and Shen, H}, title = {Neutrophil Function Conversion Driven by Immune Switchpoint Regulator Against Diabetes-Related Biofilm Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2310320}, doi = {10.1002/adma.202310320}, pmid = {38035713}, issn = {1521-4095}, abstract = {Reinforced biofilm structures and dysfunctional neutrophils induced by excessive oxidative stress contribute to the refractoriness of diabetes-related biofilm infections (DRBIs). Herein, in contrast to traditional antibacterial therapies, an immune switchpoint-driven neutrophil immune function conversion (NIFC) strategy based on a deoxyribonuclease I loaded vanadium carbide MXene (DNase-I@V2 C) nano-regulator was proposed to treat DRBIs via biofilm lysis and redirecting neutrophil functions from NETosis to phagocytosis in diabetes. Owing to its intrinsic SOD/CAT-like activities, DNase-I@V2 C effectively scavenged ROS in a high oxidative stress microenvironment to maintain the biological activity of DNase-I. By increasing the depth of biofilm penetration of DNase-I, DNase-I@V2 C thoroughly degraded extracellular DNA (eDNA) and neutrophil extracellular traps (NETs) in extracellular polymeric substances (EPS), thus breaking the physical barrier of biofilms. More importantly, as an immune switchpoint regulator, DNase-I@V2 C can skew neutrophil functions from NETosis towards phagocytosis by intercepting ROS-NE/MPO-PAD4 and activating ROS-PI3K-AKT-mTOR pathways in diabetic microenvironment, thereby eliminating biofilm infections. Biofilm lysis and synergistic neutrophil function conversion exerted favorable therapeutic effects on biofilm infections in vitro and in vivo. This study serves as a proof-of-principle demonstration of effectively achieving DRBIs with high therapeutic efficacy by regulating immune switchpoint to reverse neutrophil functions. This article is protected by copyright. All rights reserved.}, } @article {pmid38034905, year = {2023}, author = {El-Demerdash, AS and Orady, RM and Matter, AA and Ebrahem, AF}, title = {An Alternative Approach Using Nano-garlic Emulsion and its Synergy with Antibiotics for Controlling Biofilm-Producing Multidrug-Resistant Salmonella in Chicken.}, journal = {Indian journal of microbiology}, volume = {63}, number = {4}, pages = {632-644}, doi = {10.1007/s12088-023-01124-2}, pmid = {38034905}, issn = {0046-8991}, abstract = {Surface-growing antibiotic-resistant pathogenic Salmonella is emerging as a global health challenge due to its high economic loss in the poultry industry. Their pathogenesis, increasing antimicrobial resistance, and biofilm formation make them challenging to treat with traditional therapy. The identification of antimicrobial herbal ingredients may provide valuable solutions to solve this problem. Therefore, our aim is to evaluate the potency of nano garlic as the alternative of choice against multidrug-resistant (MDR) Salmonella isolates using disc diffusion and microdilution assays. Then, checkerboard titration in trays was applied, and FIC was measured to identify the type of interaction between the two antimicrobials. A disc diffusion assay revealed that neomycin was the drug of choice. The range of nano garlic MIC was 12.5-25 μg/ml, while the neomycin MIC range was 32-64 μg/ml. The FIC index established a synergistic association between the two tested drugs in 85% of isolates. An experimental model was used including nano garlic and neomycin alone and in combination against Salmonella infection. The combination therapy significantly improved body productivity and inhibited biofilm formation by more than 50% down regulating the CsgBAD, motB, and sipA operons, which are responsible for curli fimbriae production and biofilm formation in Salmonella serotypes.}, } @article {pmid38034786, year = {2023}, author = {Moradi, F and Ghaedi, A and Fooladfar, Z and Bazrgar, A}, title = {Recent advance on nanoparticles or nanomaterials with anti-multidrug resistant bacteria and anti-bacterial biofilm properties: A systematic review.}, journal = {Heliyon}, volume = {9}, number = {11}, pages = {e22105}, doi = {10.1016/j.heliyon.2023.e22105}, pmid = {38034786}, issn = {2405-8440}, abstract = {OBJECTIVE: With the wide spread of Multidrug-resistant bacteria (MDR) due to the transfer and acquisition of antibiotic resistance genes and the formation of microbial biofilm, various researchers around the world are looking for a solution to overcome these resistances. One potential strategy and the best candidate to overcome these infections is using an effective nanomaterial with antibacterial properties against them.

METHODS: and analysis: In this study, we overview nanomaterials with anti-MDR bacteria and anti-biofilm properties. Hence, we systematically explored biomedical databases (Web of Sciences, Google Scholar, PubMed, and Scopus) to categorize related studies about nanomaterial with anti-MDR bacteria and anti-biofilm activities from 2007 to December 2022.

RESULTS: In total, forty-one studies were investigated to find antibacterial and anti-biofilm information about the nanomaterial during 2007-2022. According to the collected documents, nineteen types of nanomaterial showed putative antibacterial effects such as Cu, Ag, Au, Au/Pt, TiO2, Al2O3, ZnO, Se, CuO, Cu/Ni, Cu/Zn, Fe3O4, Au/Fe3O4, Au/Ag, Au/Pt, Graphene O, and CuS. In addition, seven types of them considered as anti-biofilm agents such as Ag, ZnO, Au/Ag, Graphene O, Cu, Fe3O4, and Au/Ag.

CONCLUSION: According to the studies, each of nanomaterial has been designed with different methods and their effects against standard strains, clinical strains, MDR strains, and bacterial biofilms have been investigated in-vitro and in-vivo conditions. In addition, nanomaterials have different destructive mechanism on bacterial structures. Various nanoparticles (NP) introduced as the best candidate to designing new drug and medical equipment preventing infectious disease outbreaks by overcome antibiotic resistance and bacterial biofilm.}, } @article {pmid38034252, year = {2023}, author = {Choudhari, S and Krithikadatta, J and Vejendla, I and S, S and Doble, M}, title = {Microbial Interactions in Oral Biofilm: Evaluating Therapeutic Interventions and the Emergence of Resistance: A Narrative Review.}, journal = {Cureus}, volume = {15}, number = {10}, pages = {e48021}, doi = {10.7759/cureus.48021}, pmid = {38034252}, issn = {2168-8184}, abstract = {The oral cavity comprises numerous anatomical surfaces that are inhabited by a diverse array of bacteria, collectively forming a bacterial biofilm. Within this complex microbial community, certain bacterial species are etiologically linked to the development of common oral pathologies, such as dental caries and periodontitis, which stand as prominent instances of bacterial infections frequently encountered in clinical settings. Most biofilms are believed to be multispecies consortia. While single-species biofilms have been well-researched, mixed-species biofilms and their interactions amongst themselves have not drawn interest. The aim of the current review was to assess the various interactions of dual-species microorganisms in oral biofilm formation. Farnesol given exogenously for the treatment of biofilm can enhance or inhibit the growth of certain organisms, as seen in Candida albicans. In the age of antibiotic resistance, it is imperative to develop and uncover drugs capable of simultaneously targeting multiple species in order to mitigate antimicrobial resistance.}, } @article {pmid38033972, year = {2023}, author = {Sindhu, BU and Praveen, S and Sandeep, JN and Avinash, JL and Rajiv, NP and Rudraswamy, S}, title = {Evaluation of antimicrobial efficacy of immunoglobulin Y (IgY) against periodontal biofilm.}, journal = {Journal of oral and maxillofacial pathology : JOMFP}, volume = {27}, number = {3}, pages = {499-506}, doi = {10.4103/jomfp.jomfp_347_23}, pmid = {38033972}, issn = {0973-029X}, abstract = {BACKGROUND AND OBJECTIVES: To determine the action of immunoglobulin Y (IgY) on supragingival microbiota and on subgingival microbiota in patients with gingivitis and periodontitis through microbial reduction assay.

METHODOLOGY: 40 systemically healthy patients were divided into two groups (gingivitis and periodontitis) with 20 patients per group. Supragingival and subgingival plaque samples were collected from each patient in Group I and Group II, respectively. Sample 1 and Sample 2 from each patient were immediately transferred into sterile Eppendorf tube 1 and tube 2 with microbial transport media, respectively. Both the tubes were then immediately transferred into an anaerobic jar and sent to the microbial facility. IgY was then added to these samples. All the samples were collected in duplicate vials to check the in vitro antimicrobial activity of microbes with IgY and without IgY. Microbial reduction percentage was calculated based on the colony count comparing the colonies with and without IgY.

RESULTS: The mean CFUs in the gingivitis group with IgY samples was significantly lesser as compared to the periodontitis group. The mean CFUs in gingivitis and periodontitis group with IgY samples was significantly lesser as compared to those without IgY samples.

CONCLUSION: IgY has a significant role in the reduction of bacterial count in supragingival and subgingival plaque samples. So, IgY when used as a local drug delivery agent or mouthwash, as an adjunct to scaling and root planing may reduce gingival and periodontal diseases but further studies showing its effect must be carried out to validate the same.}, } @article {pmid38033587, year = {2023}, author = {Bakenhus, I and Jongsma, R and Michler-Kozma, D and Hölscher, L and Gabel, F and Holert, J and Philipp, B}, title = {A domesticated photoautotrophic microbial community as a biofilm model system for analyzing the influence of plastic surfaces on invertebrate grazers in limnic environments.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1238913}, doi = {10.3389/fmicb.2023.1238913}, pmid = {38033587}, issn = {1664-302X}, abstract = {The environmental fate of plastic particles in water bodies is influenced by microbial biofilm formation. Invertebrate grazers may be affected when foraging biofilms on plastics compared to biofilms on natural substrata but the mechanistic basis for these effects is unknown. For analyzing these effects in ecotoxicological assays stable and reproducible biofilm communities are required that are related to the environmental site of interest. Here, a defined biofilm community was established and used to perform grazing experiments with a freshwater snail. For this, snippets of different plastic materials were incubated in the photic zone of three different freshwater sites. Amplicon sequencing of biofilms formed on these snippets showed that the site of incubation and not the plastic material dominated the microbial community composition. From these biofilms, individual microbial strains as well as photoautotrophic consortia were isolated; these consortia consisted of heterotrophic bacteria that were apparently nourished by microalga. While biofilms formed by defined dual cultures of a microalga and an Alphaproteobacterium were not accepted by the snail P. fontinalis, a photoautotrophic consortium (Co_3) sustained growth and metabolism of this grazer. Amplicon sequencing revealed that consortium Co_3, which could be stably maintained on solid medium under photoautotrophic conditions, reproducibly formed biofilms of a defined composition on three different plastic materials and on glass surfaces. In conclusion, our study shows that the generation of domesticated photoautotrophic microbial communities is a valid novel approach for establishing laboratory ecotoxicological assays with higher environmental relevance than those based on defined microbiota.}, } @article {pmid38033560, year = {2023}, author = {Hu, Y and Webb, JS and An, SQ}, title = {Host cell-based screening assays for identification of molecules targeting Pseudomonas aeruginosa cyclic di-GMP signaling and biofilm formation.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1279922}, doi = {10.3389/fmicb.2023.1279922}, pmid = {38033560}, issn = {1664-302X}, abstract = {The rapid emergence of bacterial resistance to antibiotics in current use is occurring worldwide and poses a significant threat to global healthcare systems. Recent research to identify new effective anti-bacterial agents has focused on regulatory pathways as targets for interference. Regulatory mechanisms employing intracellular Bis-(3',5') cyclic di-guanylate (c-di-GMP) as a secondary messenger represent a distinct category of subjects. This molecule, c-di-GMP, is present in nearly all bacterial species and plays a pivotal role in governing various biological processes, encompassing antibiotic resistance, biofilm formation, and virulence. Alteration of the cellular concentrations of the nucleotide through modulation of associated signaling pathways has the potential to reduce biofilm formation or increase susceptibility of the biofilm bacteria to antibiotics. Here, we have developed a screen for compounds that alter c-di-GMP levels in Pseudomonas aeruginosa in co-culture with bronchial epithelial cells. Through the assay of 200 natural compounds, we were able to identify several substances showing promising effects on P. aeruginosa in a host biofilm infection model. Importantly, we detected compounds that inhibit c-di-GMP levels and showed significant influence on biofilm formation and virulence in P. aeruginosa in vitro and in vivo. Consequently, we offer proof-of-concept information regarding swift and practical drug screening assays, suitable for medium- to high-throughput applications, which target the c-di-GMP signaling pathways in this significant Gram-negative pathogen.}, } @article {pmid38032906, year = {2023}, author = {Gedefie, A and Alemayehu, E and Mohammed, O and Bambo, GM and Kebede, SS and Kebede, B}, title = {Prevalence of biofilm producing Acinetobacter baumannii clinical isolates: A systematic review and meta-analysis.}, journal = {PloS one}, volume = {18}, number = {11}, pages = {e0287211}, doi = {10.1371/journal.pone.0287211}, pmid = {38032906}, issn = {1932-6203}, abstract = {BACKGROUND: Acinetobacter baumannii, the first human pathogen to be designated as a "red-alert" pathogen, is on the critical priority list of pathogens requiring new antibiotics. Biofilm-associated diseases are the most common infections caused by the antibiotic-resistant bacteria A. baumannii. Multidrug-resistant strains are more easily transmitted around the world due to A. baumannii's ability to produce biofilms, which allows it to develop antibiotic resistance mechanisms and thrive in healthcare environments. As a result, A. baumannii infections are becoming increasingly common in hospital settings allover the world. As a result, a comprehensive systematic review and meta-analysis were carried out to determine the global prevalence of biofilm-producing A. baumannii clinical isolates.

METHODS: Articles were extensively searched in bibliographic databases and grey literatures using entry terms or phrases. Studies meeting eligibility criteria were extracted in MS Excel and exported into STATA version 12 software for statistical analysis. A random-effects model was used to compute the pooled prevalence of biofilm-producing A. baumannii clinical isolates. The heterogeneity was quantified by using the I2 value. Publication bias was assessed using a funnel plot and Egger's test. Sensitivity analysis was done to assess the impact of a single study on pooled effect size.

RESULT: Of the 862 studies identified, 26 studies consisted of 2123 A.baumannii clinical isolates of which 1456 were biofilm-producing. The pooled prevalence of biofilm-producing A.baumannii clinical isolates was 65.63% (95% CI = 56.70%-74.56%). There was substantial heterogeneity with an I2 value of 98.1%. Moreover, 41.34%, 33.57%, and 27.63% of isolates of strong, mild, and weak producers of biofilm. Higher prevalence was found in studies published after 2014 (66.31%); Western Pacific region (76.17%); and Asia (66.22%) followed by the African continent (57.29%).

CONCLUSION: The pooled prevalence of biofilm-producing A. baumannii clinical isolates has risen alarmingly, posing a public health risk. This indicates the burden of biofilm-producing A. baumannii infections urges routine screening and appropriate treatment for better management of hospitalized patients, as well as effective controlling of the emergence of drug resistance. Furthermore, this finding is an alert call for the stakeholders to develop strong infection prevention and antibiotics stewardship programs for the prevention and control of biofilm-producing bacterial infections.}, } @article {pmid38032880, year = {2023}, author = {Al Bataineh, MT and Alazzam, A}, title = {Transforming medical device biofilm control with surface treatment using microfabrication techniques.}, journal = {PloS one}, volume = {18}, number = {11}, pages = {e0292647}, doi = {10.1371/journal.pone.0292647}, pmid = {38032880}, issn = {1932-6203}, abstract = {Biofilm deposition on indwelling medical devices and implanted biomaterials is frequently attributed to the prevalence of resistant infections in humans. Further, the nature of persistent infections is widely believed to have a biofilm etiology. In this study, the wettability of commercially available indwelling medical devices was explored for the first time, and its effect on the formation of biofilm was determined in vitro. Surprisingly, all tested indwelling devices were found to be hydrophilic, with surface water contact angles ranging from 60° to 75°. First, we established a thriving Candida albicans biofilm growth at 24 hours. in YEPD at 30°C and 37°C plus serum in vitro at Cyclic olefin copolymer (COC) modified surface, which was subsequently confirmed via scanning electron microscopy, while their cellular metabolic function was assessed using the XTT cell viability assay. Surfaces with patterned wettability show that a contact angle of 110° (hydrophobic) inhibits C. albicans planktonic and biofilm formation completely compared to robust growth at a contact angle of 40° (hydrophilic). This finding may provide a novel antimicrobial strategy to prevent biofilm growth and antimicrobial resistance on indwelling devices and prosthetic implants. Overall, this study provides valuable insights into the surface characteristics of medical devices and their potential impact on biofilm formation, leading to the development of improved approaches to control and prevent microbial biofilms and re-infections.}, } @article {pmid38032740, year = {2023}, author = {Khan, I and Minto, RE and Kelley-Patteson, C and Singh, K and Timsina, L and Suh, LJ and Rinne, E and Van Natta, BW and Neumann, CR and Mohan, G and Lester, M and VonDerHaar, RJ and German, R and Marino, N and Hassanein, AH and Gordillo, GM and Kaplan, MH and Sen, CK and Kadin, ME and Sinha, M}, title = {Biofilm derived oxylipin 10-HOME mediated immune response in women with breast implants.}, journal = {The Journal of clinical investigation}, volume = {}, number = {}, pages = {}, doi = {10.1172/JCI165644}, pmid = {38032740}, issn = {1558-8238}, abstract = {The study investigates a mechanistic link if bacterial biofilm mediated host-pathogen interaction leads to immunological complications associated with breast implant illness (BII). Over 10 million women worldwide have breast implants. In recent years, women have described a constellation of immunological symptoms believed to be related to their breast implants. The study included 178 subjects divided in three cohorts. Eighty-six patients reported symptoms consistent with BII. Control group I (non-BII, N=55) included patients with breast implants without BII symptoms but went through explantation of the breast implant. Control group II (normal tissue, N=37) was comprised of women without an implant, whose breast tissue was removed as an unrelated clinically indicated surgical procedures. We report that periprosthetic breast tissue of BII had increased abundance of biofilm and biofilm-derived oxylipin, 10-HOME. S. epidermidis biofilm was observed to be higher in the BII group (73.33%) compared to non-BII group (16.67%, p=0.018) and the normal group (10%, p=0.036). The oxylipin was found to be immunogenic capable of polarizing naïve CD4+ T cells with a resulting Th1 subtype in vitro and in vivo. Consistently, an abundance of CD4+Th1 subtype was observed in the periprosthetic breast tissue and blood of BII subjects. Mice injected with 10-HOME also had increased Th1 subtype in blood akin to BII patients and demonstrated fatigue-like symptoms. The identification of an oxylipin-mediated mechanism of immune activation induced by local bacterial biofilm associated with BII provides insight into the possible pathogenesis of implant-associated immune symptoms of BII.}, } @article {pmid38031607, year = {2023}, author = {Aksoy, N and Vatansever, C and Adalı, C and Adaklı Aksoy, B and Fışgın, T}, title = {The Inhibitory Effects of Amylase and Streptokinase on Minimum Inhibitory Concentration of Antibiotics Used to Treat Gram Negative Bacteria Biofilm Infection on Indwelling Devices.}, journal = {Indian journal of microbiology}, volume = {63}, number = {4}, pages = {533-540}, pmid = {38031607}, issn = {0046-8991}, abstract = {The study evaluated and compared the effect of adding streptokinase and amylase to antibiotics that are already used in clinical practice to treat Gram negative bacteria biofilm infection on indwelling devices on the antibiotics' minimum inhibitory concentration (MIC). 24 h-old biofilms were developed on 96-well plate with eight clinical isolates. MIC of amikacin, cefepime, ceftazidime, colistin, meropenem, and piperacillin-tazobactam, on biofilms were measured before and after the addition of 25 U/ml streptokinase and 25 μg/ml amylase with microplate reader. The addition of streptokinase reduces the MICs of cefepime, ceftazidime, colistin, meropenem from (16, 16, 8, 4 μg/ml) to (8, 1, 1, 0.5 μg/ml) in Escherichia coli (isolate 1). While the addition of amylase reduces the MICs of only cefepime, ceftazidime from (16, 16 μg/ml) to (2, 4 μg/ml) in E. coli (isolate 1). In Pseudomonas aeruginosa (isolate 4), the MICs of amikacin, cefepime, ceftazidime, colistin and meropenem (64, 16, 32, 4, 32 μg/ml) reduced to (2, 1, 0.5, 0.25, 0.5 μg/ml) with streptokinase and (4, 4, 4, 2, 0.5 μg/ml) with amylase respectively. Similar inhibitions were seen in Pseudomonas putida, Proteus mirabilis. We can conclude that the addition of streptokinase and amylase were effective in reducing the MICs of antibiotics that are commonly used to treat Gram negative bacteria biofilm infection on indwelling devices, thereby increasing susceptibility of bacteria to antibiotics. Streptokinase obviously had a greater effect than amylase, implying that it should be prioritized in future in vivo and clinical studies to obtain successful therapy with antibiotics on biofilm infections.}, } @article {pmid38030866, year = {2023}, author = {Jalil, AT and Alrawe, RTA and Al-Saffar, MA and Shaghnab, ML and Merza, MS and Abosaooda, M and Latef, R}, title = {The use of combination therapy for the improvement of colistin activity against bacterial biofilm.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {38030866}, issn = {1678-4405}, abstract = {Colistin is used as a last resort for the management of infections caused by multi-drug resistant (MDR) bacteria. However, the use of this antibiotic could lead to different side effects, such as nephrotoxicity, in most patients, and the high prevalence of colistin-resistant strains restricts the use of colistin in the clinical setting. Additionally, colistin could induce resistance through the increased formation of biofilm; biofilm-embedded cells are highly resistant to antibiotics, and as with other antibiotics, colistin is impaired by bacteria in the biofilm community. In this regard, the researchers used combination therapy for the enhancement of colistin activity against bacterial biofilm, especially MDR bacteria. Different antibacterial agents, such as antimicrobial peptides, bacteriophages, natural compounds, antibiotics from different families, N-acetylcysteine, and quorum-sensing inhibitors, showed promising results when combined with colistin. Additionally, the use of different drug platforms could also boost the efficacy of this antibiotic against biofilm. The mentioned colistin-based combination therapy not only could suppress the formation of biofilm but also could destroy the established biofilm. These kinds of treatments also avoided the emergence of colistin-resistant subpopulations, reduced the required dosage of colistin for inhibition of biofilm, and finally enhanced the dosage of this antibiotic at the site of infection. However, the exact interaction of colistin with other antibacterial agents has not been elucidated yet; therefore, further studies are required to identify the precise mechanism underlying the efficient removal of biofilms by colistin-based combination therapy.}, } @article {pmid38030114, year = {2023}, author = {Lago, A and Silva, B and Tavares, T}, title = {Sustainable permeable biobarriers for atrazine removal in packed bed biofilm reactors.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {123033}, doi = {10.1016/j.envpol.2023.123033}, pmid = {38030114}, issn = {1873-6424}, abstract = {The synergy between two supported bacterial biofilms of S. equisimilis and P. putida and a sustainable biocarrier (raw pine) was studied, working both as biobarriers for the treatment of water contaminated with atrazine. Firstly, the effects of ATZ exposure on bacterial growth were evaluated, with Gram-positive S. equisimilis being a more tolerant bacterium to higher amounts of the herbicide. The bioremoval of ATZ by S. equisimilis concentrated biomass was then assessed, reaching around 83.5% after 15 days due to the potential degradation by the biomass and biosorption by the solids, with overlapping of both mechanisms. The optimization of bacterial biofilm attachment onto raw pine prior to bioremoval assays in lab-scale packed bed biofilm reactors was performed by varying initial biomass concentration, inocula growth time and hydrodynamic conditions. Lastly, the optimized biosystems were tested as sustainable remediation designs to treat water contaminated with the selected herbicide. Results reveal an added beneficial effect towards the bioremoval of atrazine using supported biofilms onto raw pine, reaching 90.42% and 79.71% by S. equisimilis and P. putida biofilms, respectively, over 58.31% increase when compared to sorption on fixed bed of pine. The coupling of biosorption/biodegradation favors the bioremoval process significantly.}, } @article {pmid38030019, year = {2023}, author = {Thombre, D and Shelar, A and Nakhale, S and Khairnar, B and Karale, N and Sangshetti, J and Nile, SH and Patil, R}, title = {Green synthesis of biogenic selenium nanoparticles functionalized with ginger dietary extract targeting virulence factor and biofilm formation in Candida albicans.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106462}, doi = {10.1016/j.micpath.2023.106462}, pmid = {38030019}, issn = {1096-1208}, abstract = {To treat the systemic infections caused by Candida albicans (C. albicans), various drugs have been used, however, infections still persisted due to virulence factors and increasing antifungal resistance. As a solution to this problem, we synthesized selenium nanoparticles (SeNPs) by using Bacillus cereus bacteria. This is the first study to report a higher (70 %) reduction of selenite ions into SeNPs in under 6 h. The as-synthesized, biogenic SeNPs were used to deliver bioactive constituents of aqueous extract of ginger for inhibiting the growth and biofilm (virulence factors) in C. albicans. UV-visible spectroscopy revealed a characteristic absorption at 280 nm, and Raman spectroscopy showed a characteristic peak shift at 253 cm[-1] for the biogenic SeNPs. The synthesized SeNPs are spherical with 240-250 nm in size as determined by electron microscopy. Fourier transform infrared spectroscopy (FTIR) confirmed the functionalization of antifungal constituents of ginger over the SeNPs (formation of Ginger@SeNPs nanoconjugates). In contrast to biogenic SeNPs, nanoconjugates were active against C. albicans for inhibiting growth and biofilm (virulence factor) formation. To understand the antifungal action of nanoconjugates, genes involved in the biofilm were targeted. In order to reveal antifungal mechanism of nanoconjugates', real-time polymerase chain reaction (RT-PCR) analysis was performed. Nanoconjugates inhibited 25 % growth of human embryonic kidney (HEK) 293 cell line, indicating moderate cytotoxicity of active nanoconjugates in an in-vitro cytotoxicity study. Therefore, biogenic SeNPs conjugated with ginger dietary extract may be a potential antifungal agent and drug carrier for inhibiting C. albicans growth and biofilm (virulence factor) formation.}, } @article {pmid38029487, year = {2023}, author = {Wu, KK and Zhao, L and Wang, ZH and Sun, ZF and Wu, JT and Chen, C and Xing, DF and Yang, SS and Wang, AJ and Zhang, YF and Ren, NQ}, title = {Simultaneous biogas upgrading and medium-chain fatty acids production using a dual membrane biofilm reactor.}, journal = {Water research}, volume = {249}, number = {}, pages = {120915}, doi = {10.1016/j.watres.2023.120915}, pmid = {38029487}, issn = {1879-2448}, abstract = {Utilizing H2-assisted ex-situ biogas upgrading and acetate recovery holds great promise for achieving high value utilization of biogas. However, it faces a significant challenge due to acetate's high solubility and limited economic value. To address this challenge, we propose an innovative strategy for simultaneous upgrading of biogas and the production of medium-chain fatty acids (MCFAs). A series of batch tests evaluated the strategy's efficiency under varying initial gas ratios (v/v) of H2, CH4, CO2, along with varying ethanol concentrations. The results identified the optimal conditions as initial gas ratios of 3H2:3CH4:2CO2 and an ethanol concentration of 241.2 mmol L[-1], leading to maximum CH4 purity (97.2 %), MCFAs yield (54.2 ± 2.1 mmol L[-1]), and MCFAs carbon-flow distribution (62.3 %). Additionally, an analysis of the microbial community's response to varying conditions highlighted the crucial roles played by microorganisms such as Clostridium, Proteiniphilum, Sporanaerobacter, and Bacteroides in synergistically assimilating H2 and CO2 for MCFAs production. Furthermore, a 160-day continuous operation using a dual-membrane aerated biofilm reactor (dMBfR) was conducted. Remarkable achievements were made at a hydraulic retention time of 2 days, including an upgraded CH4 content of 96.4 ± 0.3 %, ethanol utilization ratio (URethanol) of 95.7 %, MCFAs production rate of 28.8 ± 0.3 mmol L[-1] d[-1], and MCFAs carbon-flow distribution of 70 ± 0.8 %. This enhancement is proved to be an efficient in biogas upgrading and MCFAs production. These results lay the foundation for maximizing the value of biogas, reducing CO2 emissions, and providing valuable insights into resource recovery.}, } @article {pmid38029154, year = {2023}, author = {Zhang, T and Liu, Z and Wang, H and Zhang, H and Li, H and Lu, W and Zhu, J}, title = {Multi-omics analysis reveals genes and metabolites involved in Bifidobacterium pseudocatenulatum biofilm formation.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1287680}, doi = {10.3389/fmicb.2023.1287680}, pmid = {38029154}, issn = {1664-302X}, abstract = {Bacterial biofilm is an emerging form of life that involves cell populations living embedded in a self-produced matrix of extracellular polymeric substances (EPS). Currently, little is known about the molecular mechanisms of Bifidobacterium biofilm formation. We used the Bifidobacterium biofilm fermentation system to preparation of biofilms on wheat fibers, and multi-omics analysis of both B. pseudocatenulatum biofilms and planktonic cells were performed to identify genes and metabolites involved in biofilm formation. The average diameter of wheat fibers was around 50 μm, while the diameter of particle in wheat fibers culture of B. pseudocatenulatum was over 260 μm at 22 h with 78.96% biofilm formation rate (BR), and the field emission scanning electron microscopy (FESEM) results showed that biofilm cells on the surface of wheat fibers secreted EPS. Transcriptomic analysis indicated that genes associated with stress response (groS, mntH, nth, pdtaR, pstA, pstC, radA, rbpA, whiB, ybjG), quorum sensing (dppC, livM, luxS, sapF), polysaccharide metabolic process (rfbX, galE, zwf, opcA, glgC, glgP, gtfA) may be involved in biofilm formation. In addition, 17 weighted gene co-expression network analysis (WGCNA) modules were identified and two of them positively correlated to BR. Metabolomic analysis indicated that amino acids and amides; organic acids, alcohols and esters; and sugar (trehalose-6-phosphate, uridine diphosphategalactose, uridine diphosphate-N-acetylglucosamine) were main metabolites during biofilm formation. These results indicate that stress response, quorum sensing (QS), and EPS production are essential during B. pseudocatenulatum biofilm formation.}, } @article {pmid38027799, year = {2023}, author = {Oliveira, RIS and de Oliveira, IN and de Conto, JF and de Souza, AM and Batistuzzo de Medeiros, SR and Egues, SM and Padilha, FF and Hernández-Macedo, ML}, title = {Photocatalytic effect of N-TiO2 conjugated with folic acid against biofilm-forming resistant bacteria.}, journal = {Heliyon}, volume = {9}, number = {11}, pages = {e22108}, doi = {10.1016/j.heliyon.2023.e22108}, pmid = {38027799}, issn = {2405-8440}, abstract = {Antibiotic resistance challenges the treatment of bacterial biofilm-related infections, but the use of nanoparticles as a treatment is a promising strategy to overcome bacterial infections. This study applied nitrogen-doped titanium dioxide (N-TiO2) conjugated with folic acid (FA) on biofilm-forming resistant bacteria. The photocatalytic effect of TiO2 nanoparticles (NPs) was studied under ultraviolet (UV), visible light, and dark conditions at 60, 120, and 180 min against planktonic cells and biofilms of Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. TiO2 NPs were in the anatase phase, spherical shaped with sizes of 10-13 nm, and effectively doped and conjugated with N and FA. The FA-conjugated nanoparticles (N-TiO2-FA and FA-TiO2) were shown to have a bactericidal effect on all bacteria between 60 and 180 min under UV and visible light conditions. Concerning biofilms, N-TiO2-FA was shown to have a highly disruptive effect on all bacterial biofilms under UV irradiation at 180 min. Meanwhile, the nanoparticles did not show DNA damaging potential and they had no cytostatic effect, indicating that these NPs are biocompatible. In sum, nanoparticle conjugation with FA promoted photocatalytic effectiveness, revealing the promise this nanomaterial holds as a biocompatible antimicrobial agent.}, } @article {pmid38027585, year = {2023}, author = {Zhang, S and Shu, Y and Zhang, W and Xu, Z and Li, Y and Li, S and Li, Q and Xiong, R and Long, Y and Liu, J and Zhang, Y and Chen, C and Lu, Y}, title = {Quorum sensing N-acyl homoserine lactones-SdiA enhances the biofilm formation of E. coli by regulating sRNA CsrB expression.}, journal = {Heliyon}, volume = {9}, number = {11}, pages = {e21658}, doi = {10.1016/j.heliyon.2023.e21658}, pmid = {38027585}, issn = {2405-8440}, abstract = {As an important virulence phenotype of Escherichia coli, the regulation mechanism of biofilm by non-coding RNA and quorum sensing system has not been clarified. Here, by transcriptome sequencing and RT-PCR analysis, we found CsrB, a non-coding RNA of the carbon storage regulation system, was positively regulated by the LuxR protein SdiA. Furthermore, β-galactosidase reporter assays showed that SdiA enhanced promoter transcriptional activity of csrB. The consistent dynamic expression levels of SdiA and CsrB during Escherichia coli growth were also detected. Moreover, curli assays and biofilm assays showed sdiA deficiency in Escherichia coli SM10λπ or BW25113 led to a decreased formation of biofilm, and was significantly restored by over-expression of CsrB. Interestingly, the regulations of SdiA on CsrB in biofilm formation were enhanced by quorum sensing signal molecules AHLs. In conclusion, SdiA plays a crucial role in Escherichia coli biofilm formation by regulating the expression of non-coding RNA CsrB. Our study provides new insights into SdiA-non-coding RNA regulatory network involved in Escherichia coli biofilm formation.}, } @article {pmid38025836, year = {2023}, author = {Wächter, J and Vestweber, PK and Planz, V and Windbergs, M}, title = {Unravelling host-pathogen interactions by biofilm infected human wound models.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100164}, doi = {10.1016/j.bioflm.2023.100164}, pmid = {38025836}, issn = {2590-2075}, abstract = {Approximately 80 % of persistent wound infections are affected by the presence of bacterial biofilms, resulting in a severe clinical challenge associated with prolonged healing periods, increased morbidity, and high healthcare costs. Unfortunately, in vitro models for wound infection research almost exclusively focus on early infection stages with planktonic bacteria. In this study, we present a new approach to emulate biofilm-infected human wounds by three-dimensional human in vitro systems. For this purpose, a matured biofilm consisting of the clinical key wound pathogen Pseudomonas aeruginosa was pre-cultivated on electrospun scaffolds allowing for non-destructive transfer of the matured biofilm to human in vitro wound models. We infected tissue-engineered human in vitro skin models as well as ex vivo human skin explants with the biofilm and analyzed structural tissue characteristics, biofilm growth behavior, and biofilm-tissue interactions. The structural development of biofilms in close proximity to the tissue, resulting in high bacterial burden and in vivo-like morphology, confirmed a manifest wound infection on all tested wound models, validating their applicability for general investigations of biofilm growth and structure. The extent of bacterial colonization of the wound bed, as well as the subsequent changes in molecular composition of skin tissue, were inherently linked to the characteristics of the underlying wound models including their viability and origin. Notably, the immune response observed in viable ex vivo and in vitro models was consistent with previous in vivo reports. While ex vivo models offered greater complexity and closer similarity to the in vivo conditions, in vitro models consistently demonstrated higher reproducibility. As a consequence, when focusing on direct biofilm-skin interactions, the viability of the wound models as well as their advantages and limitations should be aligned to the particular research question of future studies. Altogether, the novel model allows for a systematic investigation of host-pathogen interactions of bacterial biofilms and human wound tissue, also paving the way for development and predictive testing of novel therapeutics to combat biofilm-infected wounds.}, } @article {pmid38024522, year = {2023}, author = {Mirzahosseini, HK and Najmeddin, F and Najafi, A and Ahmadi, A and Sharifnia, H and Khaledi, A and Mojtahedzadeh, M}, title = {Correlation of biofilm formation, virulence factors, and phylogenetic groups among Escherichia coli strains causing urinary tract infection: A global systematic review and meta-analysis.}, journal = {Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences}, volume = {28}, number = {}, pages = {66}, doi = {10.4103/jrms.jrms_637_22}, pmid = {38024522}, issn = {1735-1995}, abstract = {BACKGROUND: Different virulence factors are involved in the pathogenesis of urinary tract infection (UTI) caused by Uropathogenic Escherichia coli (UPEC); hence, this study aimed to study the prevalence of biofilm formation, virulence factors, and phylogenetic groups and their correlation with biofilm formation among UPEC isolates through a systematic review and meta-analysis.

MATERIALS AND METHODS: A literature search was conducted from 1, 2000, to the end of 2021 in different databases for studies that reported biofilm together with virulence genes or phylogenetic groups in UPEC isolates from patients with UTI according to PRISMA protocol. Data were analyzed by Comprehensive meta-analysis software.

RESULTS: The pooled prevalence of biofilm formers was 74.7%. The combined prevalence of phylogenetic Groups A, B1, B2, and D (s) were reported at 19.6%, 11%, 50.7%, and 20.5%, respectively. The most common virulence genes reported worldwide were fimA, ecpA, and fimH, with a combined prevalence of 90.3%, 86.6%, and 64.9%, respectively. The pooled prevalence of biofilm formation in UPEC isolates with phylogenetic Groups A, B1, B2, D, C, and F were 12.4%, 8.7%, 33.7%, 12.4%, 2.6%, and 2.65%, respectively. Several studies showed a correlation between biofilm production and virulence genes, or phylogenetic groups.

CONCLUSION: Regarding data obtained, the high level of combined biofilm formation (74.7%) and the presence of a positive correlation between biofilm production and virulence genes, or phylogenetic groups as reported by the most studies included in the present review, indicates an important role of biofilm in the persistence of UPEC in the UTI.}, } @article {pmid38024323, year = {2023}, author = {Gnilitskyi, I and Rymar, S and Iungin, O and Vyshnevskyy, O and Parisse, P and Potters, G and Zayats, AV and Moshynets, O}, title = {Femtosecond laser modified metal surfaces alter biofilm architecture and reduce bacterial biofilm formation.}, journal = {Nanoscale advances}, volume = {5}, number = {23}, pages = {6659-6669}, doi = {10.1039/d3na00599b}, pmid = {38024323}, issn = {2516-0230}, abstract = {Biofilm formation, or microfouling, is a basic strategy of bacteria to colonise a surface and may happen on surfaces of any nature whenever bacteria are present. Biofilms are hard to eradicate due to the matrix in which the bacteria reside, consisting of strong, adhesive and adaptive self-produced polymers such as eDNA and functional amyloids. Targeting a biofilm matrix may be a promising strategy to prevent biofilm formation. Here, femtosecond laser irradiation was used to modify the stainless steel surface in order to introduce either conical spike or conical groove textures. The resulting topography consists of hierarchical nano-microstructures which substantially increase roughness. The biofilms of two model bacterial strains, P. aeruginosa PA01 and S. aureus ATCC29423, formed on such nanotextured metal surfaces, were considerably modified due to a substantial reduction in amyloid production and due to changes in eDNA surface adhesion, leading to significant reduction in biofilm biomass. Altering the topography of the metal surface, therefore, radically diminishes biofilm development solely by altering biofilm architecture. At the same time, growth and colonisation of the surface by eukaryotic adipose tissue-derived stem cells were apparently enhanced, leading to possible further advantages in controlling eukaryotic growth while suppressing prokaryotic contamination. The obtained results are important for developing anti-bacterial surfaces for numerous applications.}, } @article {pmid38024149, year = {2023}, author = {Faustova, MO and Chumak, YV and Loban', GA and Ananieva, MM and Havryliev, VM}, title = {Decamethoxin and chlorhexidine bigluconate effect on the adhesive and biofilm-forming properties of Streptococcus mitis.}, journal = {Frontiers in oral health}, volume = {4}, number = {}, pages = {1268676}, doi = {10.3389/froh.2023.1268676}, pmid = {38024149}, issn = {2673-4842}, abstract = {THE AIM OF THE STUDY: Was to investigate the effect of antiseptics on the adhesive and biofilm-forming properties of clinical S.mitis isolates isolated from the oral cavity of patients with an infectious and inflammatory post-extraction complication.

MATERIALS AND METHODS: Twenty four clinical isolates of S.mitis isolated from patients were studied. The studied antiseptics included 0.02% aqueous solution of decamethoxin and 0.05% solution of chlorhexidine bigluconate. Adhesion of clinical isolates under the action of decamethoxin and chlorhexidine bigluconate was determined by the method of V.I. Brillis. The biofilm-forming properties of clinical isolates were studied using the "microtiter plate test" according to G.D. Christensen.

RESULTS: The studied clinical isolates of S.mitis are classified as highly adherent microorganisms. Action of decamethoxin on clinical isolates decreases the adhesion index of the studied isolates in comparison with the adhesion index of the control culture. Action of chlorhexidine bigluconate on S.mitis isolates increases of adhession of the studied clinical isolates in comparison with the control. After the effect of decamethoxin, the optical density of clinical isolates decreased considering the optical density results of the control. The clinical isolates left an average film-forming capacity even after chlorhexidine bigluconate action.

CONCLUSIONS: Clinical isolates of S.mitis are highly adherent microorganisms. The antiseptic decamethoxin decreases the adhesion index of these bacteria, while chlorhexidine bigluconate increases the adhesion index of clinical S.mitis isolates. Clinical S. mitis isolates have an average biofilm formation capacity index. The antiseptic decamethoxin inhibits the biofilm formation capacity of S.mitis from medium to low.}, } @article {pmid38023795, year = {2023}, author = {Ibrahim, GI and Jawad, HA}, title = {Investigating the effect of Er,Cr:YSGG laser agitation of sodium hypochlorite on the removal of mature biofilm in the complex root canal systems using atomic force microscopy.}, journal = {Journal of dental research, dental clinics, dental prospects}, volume = {17}, number = {3}, pages = {154-161}, doi = {10.34172/joddd.2023.40463}, pmid = {38023795}, issn = {2008-210X}, abstract = {BACKGROUND: Endodontic infections caused by remaining biofilm following disinfection with chemical fluids encourage secondary bacterial infection; hence, employing laser pulses to activate the fluids is advised to improve microbial biofilm clearance. This study investigated the performance of Er,Cr:YSGG laser in photon-induced photoacoustic streaming (PIPS) agitation of 5.25% sodium hypochlorite (NaOCl) to enhance the removal of mature Enterococcus faecalis (E. faecalis) biofilms in complex root canal systems.

METHODS: The mesial roots of the lower first and second molars were separated and inoculated with E. faecalis bacteria for 30 days. The roots were irrigated with 5.25% NaOCl, some of them were agitated with passive ultrasonic irrigation (PUI), and the other roots were agitated by Er,Cr:YSGG laser using PIPS at 60 µs/pulse, 5 Hz, and 0.25, 0.5, 0.75, 1, and 1.25 W. An atomic force microscope (AFM) was used as a new method to obtain the results in the isthmus area; the results that have been obtained from each group were compared with each other. ANOVA was utilized to compare the means of the test groups.

RESULTS: Based on the AFM and SEM analyses, laser agitation and passive ultrasonic activation groups have shown higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05).

CONCLUSION: Based on the findings of this investigation, the agitation of 5.25% NaOCl solution by Er,Cr:YSGG laser in PIPS at (60 µs/pulse, 5 Hz, 1.25 W) offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with syringe irrigation and passive ultrasonic activation technique.}, } @article {pmid38023107, year = {2023}, author = {Shrestha, O and Shrestha, N and Khanal, S and Pokhrel, S and Maharjan, S and Thapa, TB and Khanal, PR and Joshi, G}, title = {Inhibition and Reduction of Biofilm Production along with Their Antibiogram Pattern among Gram-Negative Clinical Isolates.}, journal = {International journal of biomaterials}, volume = {2023}, number = {}, pages = {6619268}, doi = {10.1155/2023/6619268}, pmid = {38023107}, issn = {1687-8787}, abstract = {BACKGROUND: Bacterial biofilm is a significant virulence factor threatening patients, leading to chronic infections and economic burdens. Therefore, it is crucial to identify biofilm production, its inhibition, and reduction. In this study, we investigated biofilm production among Gram-negative isolates and assessed the inhibitory and reduction potential of ethylene diamine tetra acetic acid (EDTA) and dimethyl sulfoxide (DMSO) towards them. In addition, we studied the antimicrobial resistance pattern of the Gram-negative isolates.

METHODS: Bacterial isolation and identification was done using standard microbiological techniques, following the Clinical and Laboratory Standards Institute (CLSI) guideline, 28th edition. The Kirby-Bauer disk diffusion method was used to determine the antibiotic susceptibility pattern of the isolates, and β-lactamase production was tested via the combination disk method. Biofilm formation was detected through the tissue culture plate (TCP) method. Different concentrations of EDTA and DMSO were used to determine their inhibitory and reduction properties against the biofilm. Both inhibition and reduction by the various concentrations of EDTA and DMSO were analyzed using paired t-tests.

RESULTS: Among the 110 clinical isolates, 61.8% (68) were found to be multidrug resistant (MDR). 30% (33/110) of the isolates were extended-spectrum β-lactamase (ESBL) producers, 14.5% (16/110) were metallo-β-lactamase (MBL), and 8% (9/110) were Klebsiella pneumoniae carbapenemase (KPC) producers. Biofilm formation was detected in 35.4% of the isolates. Biofilm-producing organisms showed the highest resistance to antibiotics such as cephalosporins, chloramphenicol, gentamicin, and carbapenem. The inhibition and reduction of biofilm were significantly lower (p < 0.05) for 1 mM of EDTA and 2% of DMSO.

CONCLUSION: Isolates forming biofilm had a higher resistance rate and β-lactamase production compared to biofilm nonproducers. EDTA and DMSO were found to be potential antibiofilm agents. Hence, EDTA and DMSO might be an effective antibiofilm agent to control biofilm-associated infections.}, } @article {pmid38022156, year = {2023}, author = {Girija, ASS}, title = {Prediction of Antigenic Vaccine Peptide Candidates From BfmRS Associated With Biofilm Formation in Acinetobacter baumannii.}, journal = {Cureus}, volume = {15}, number = {10}, pages = {e47804}, doi = {10.7759/cureus.47804}, pmid = {38022156}, issn = {2168-8184}, abstract = {INTRODUCTION: A. baumannii is categorized as a priority pathogen due to its propensity for multi-drug resistance, exhibiting resistance against the last resort of antibiotics. It is also considered a potent nosocomial pathogen, so targeting the microbe using novel strategies would be the need of the hour. In this context, the in-silico computational approach would serve the best to design the possible epitope peptides, which may be further considered for the experimental trials for their immunological response. Objective: To predict the immune-dominant epitope peptide candidates against the bfmR and bfmS proteins mediating the two-component system adaptation in the formation of biofilm in A. baumannii.

MATERIALS AND METHODS: 11 different FASTA sequences of bfmR and bfmS from A. baumannii strains retrieved based on the blast-p similarity search tool were subjected to linear epitope B-cell epitope predictions under the IEDB B-cell epitope prediction server. Further analysis on antigenicity, allergenicity, and toxigenicity was achieved using the AntigenPro, Vaxijen, and AlgPred tools, with the physical and chemical properties evaluated using the Expasy Protparam server. Selection of the immunodominant peptides for T-cells was done through the databases under IEDB. The final assessment of protein-TLR2 interactions was done by MHC cluster servers.

RESULTS: Four peptide sequences (E1-E4) were predicted for B-cell dominance, with E1, E2, and E4 as probable antigens. All were soluble and non-toxigenic. E1 and E3 were considered non-allergens. GRAVY values were negative for all the peptides, indicating the protein to be hydrophilic in nature. Analysis of the T-cell epitopes was promising, with 100% conservancy for class-I HLA alleles, high interaction scores for similarity with TLR2, and more hydrogen bonds for E2, followed by other epitope peptides.

CONCLUSION: The promising four epitopes, as predicted for bfmR and bfmS in the present study, suggest their potent role as possible candidates for the design of vaccines targeting the TCS of A. baumannii, recommending further in vitro and in vivo experimental validation.}, } @article {pmid38021948, year = {2023}, author = {Ramsundar, K and Jain, RK and Pitchaipillai, SG}, title = {Inhibition of Quorum Sensing Controlled Virulence Factors and Biofilm Formation of Streptococcus mutans Isolated From Orthodontic Subjects by 4-Hydroxycinnamic Acid.}, journal = {Cureus}, volume = {15}, number = {10}, pages = {e47490}, doi = {10.7759/cureus.47490}, pmid = {38021948}, issn = {2168-8184}, abstract = {Introduction Dental plaque biofilms are a collection of microorganisms that are adhered to the tooth enamel surface. Inhibition of plaque biofilms is required to prevent dental caries and periodontitis and currently, there are many chemical and herbal products in use for inhibition of biofilms but with limited success. Materials and methods Dental plaque collection was done from subjects undergoing orthodontic therapy followed by isolation of Streptococcus mutans. Isolated S. mutans were subjected to disk diffusion assay with 4-HCA (baseline 10mg/mL) for the zone of inhibition and broth micro-dilution to evaluate the minimum inhibitory concentration (MIC) and sub-MIC. Crystal violet staining was done for biofilm inhibition assay. Results Growth of S. mutans was inhibited by 4-HCA at concentrations as low as 0.31 mg/mL. 4-HCA (40μL) inhibited the bacterial growth and a clear zone (15 mm) was observed. 4-Hydroxycinnamic acids treated culture showed progressive reduction in the biofilm production at the concentration of 0.01 mg/mL. The 4-HCA concentration as low as 4 mg and 2 mg has remarkably inhibited biofilm formation of 49.3% and 34.3%, respectively. Conclusion The anti-quorum sensing and anti-biofilm activity of 4-Hydroxycinnamic acid against S. mutans isolated from subjects undergoing orthodontic treatment showed a remarkable result.}, } @article {pmid38021608, year = {2023}, author = {Valan, AS and Krithikadatta, J and Doble, M and Lakshmipathy, M}, title = {Biomimetic Approach to Counter Streptococcus mutans Biofilm: An In Vitro Study on Seashells.}, journal = {Cureus}, volume = {15}, number = {10}, pages = {e47758}, doi = {10.7759/cureus.47758}, pmid = {38021608}, issn = {2168-8184}, abstract = {Aim This study aimed to investigate the anti-adherent property of the seashell surface and periostracum to prevent the formation of Streptococcus mutans biofilm. Materials and methods The seashells were initially collected from the natural urban beach, and an antibiofilm assay of the shells with and without periostracum was performed against Streptococcus mutans. Furthermore, the seashells were analyzed with a stylus profilometer (Mitutoyo Surftest SJ-301, Mitutoyo America Corporation, Illinois, USA), atomic force microscope (AFM; Nanosurf Easyscan 2, Nanosurf Inc., USA), contact angle assessment, Fourier-transform infrared (FTIR) spectroscopy analysis, and scanning electron microscopy (SEM; JEOL USA, Inc., FE-SEM IT800, Massachusetts, USA) analysis. The ability of seashells to prevent the attachment of Streptococcus mutans and form a biofilm with and without periostracum was studied by crystal violet assay. Results The results revealed that shells without periostracum promoted higher biofilm formation when compared to those having intact periostracum (by 15%, p<0.001). Shell 1 showed the highest biofilm formation, whereas shell 3 showed the least biofilm formation due to the differences in their surface morphologies. The remaining shells (4, 2, 6, and 5) showed interspersed biofilm formation. Conclusion In summary, our study was able to correlate the topologies of the shell surface with the biofilm formed by Streptococcus mutans with the wetting behavior of those shell surfaces and their roughness. More hydrophobic surfaces (with intact periostracum) were observed to lead to less attachment (correlation coefficient=-0.67). This study can pave the way for designing such biomimetic surfaces to prevent bacterial attachment.}, } @article {pmid38021185, year = {2022}, author = {Săndulescu, M}, title = {Peri-implantitis, biofilm contamination and peri-implant bone loss.}, journal = {Germs}, volume = {12}, number = {4}, pages = {432-433}, doi = {10.18683/germs.2022.1348}, pmid = {38021185}, issn = {2248-2997}, } @article {pmid38019707, year = {2023}, author = {Li, JG and Chen, XF and Lu, TY and Zhang, J and Dai, SH and Sun, J and Liu, YH and Liao, XP and Zhou, YF}, title = {Increased Activity of β-Lactam Antibiotics in Combination with Carvacrol against MRSA Bacteremia and Catheter-Associated Biofilm Infections.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00338}, pmid = {38019707}, issn = {2373-8227}, abstract = {β-Lactam antibiotics are the mainstay for the treatment of staphylococcal infections, but their utility is greatly limited by the emergence and rapid dissemination of methicillin-resistant Staphylococcus aureus (MRSA). Herein, we evaluated the ability of the plant-derived monoterpene carvacrol to act as an antibiotic adjuvant, revitalizing the anti-MRSA activity of β-lactam antibiotics. Increased susceptibility of MRSA to β-lactam antibiotics and significant synergistic activities were observed with carvacrol-based combinations. Carvacrol significantly inhibited MRSA biofilms and reduced the production of exopolysaccharide, polysaccharide intercellular adhesin, and extracellular DNA and showed synergistic biofilm inhibition in combination with β-lactams. Transcriptome analysis revealed profound downregulation in the expression of genes involved in two-component systems and S. aureus infection. Mechanistic studies indicate that carvacrol inhibits the expression of staphylococcal accessory regulator sarA and interferes with SarA-mecA promoter binding that decreases mecA-mediated β-lactam resistance. Consistently, the in vivo experiment also supported that carvacrol restored MRSA sensitivity to β-lactam antibiotic treatments in both murine models of bacteremia and biofilm-associated infection. Our results indicated that carvacrol has a potential role as a combinatorial partner with β-lactam antibiotics to address MRSA infections.}, } @article {pmid38019310, year = {2023}, author = {Jayakumar, D and Mini, M and Kumar, P and Vaikkathillam, P and Mohan, A and Khan, S}, title = {Synergistic Effect of Thymol-Ciprofloxacin Combination on Planktonic Cells and Biofilm of Pseudomonas aeruginosa.}, journal = {Current microbiology}, volume = {81}, number = {1}, pages = {23}, pmid = {38019310}, issn = {1432-0991}, abstract = {Pseudomonas aeruginosa is an opportunistic bacteria causing severe and life-threatening infections in individuals with weakened immune systems. P. aeruginosa forms antibiotic-resistant biofilms, rendering it challenging to treat; hence, alternate therapies are required to eliminate it. Treatment of infections using a combination of drugs is gaining momentum to combat drug-resistant pathogens, including P. aeruginosa. This study explores the synergistic effects of Thymol in combination with Ciprofloxacin, Amikacin and Colistin against planktonic cells and biofilm of P. aeruginosa. Thymol in combination with Ciprofloxacin yields the fractional inhibitory concentration index values 0.156 and 0.375 in P. aeruginosa strains, GC14 and ATCC 9027, respectively, highlighting a robust synergistic effect on both the planktonic and biofilm of P. aeruginosa. The results showed that Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) were the most effective combination with 95 and 93.5% total biofilm inhibition in GC14 and PA27, respectively, compared to the Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) alone. Our findings suggest that the combinations of Thymol and Ciprofloxacin may be a potential therapeutic strategy to address the issue of infections caused by P. aeruginosa biofilms.}, } @article {pmid38018987, year = {2023}, author = {Liu, P and Kang, X and Chen, X and Luo, X and Li, C and Wang, G}, title = {Quercetin targets SarA of methicillin-resistant Staphylococcus aureus to mitigate biofilm formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0272223}, doi = {10.1128/spectrum.02722-23}, pmid = {38018987}, issn = {2165-0497}, abstract = {Anti-biofilm is an important strategy against Staphylococcus aureus chronic infection. SarA is a positive regulator of biofilm formation in S. aureus. In this study, we identified the SarA inhibitor quercetin using computer simulation screening. Previous studies have shown that quercetin inhibits biofilm; however, the underlying mechanism remains unknown. This study revealed the inhibitory effect of quercetin on the SarA protein. We also isolated the SarA protein and confirmed its interaction with quercetin in vitro. Besides, the inhibitory effect of quercetin on the transcription and translation levels of the SarA protein was also determined. The effects of quercetin on S. aureus biofilm inhibition and biofilm components were consistent with the changes in the transcription level of biofilm-related genes regulated by SarA. In summary, our study revealed the mechanism by which quercetin affects biofilm formation by inhibiting the transcriptional regulator SarA of S. aureus.}, } @article {pmid38017355, year = {2023}, author = {Hemmati, J and Nazari, M and Ahmadi, A and Bayati, M and Jalili, M and Taheri, M and Mohammadi, Y and Asghari, B}, title = {In vitro evaluation of biofilm phenotypic and genotypic characteristics among clinical isolates of Pseudomonas aeruginosa in Hamadan, West of Iran.}, journal = {Journal of applied genetics}, volume = {}, number = {}, pages = {}, pmid = {38017355}, issn = {2190-3883}, abstract = {Due to high antimicrobial resistance and biofilm-forming ability, Pseudomonas aeruginosa is one of the seriously life-threatening agents causing chronic and nosocomial infections. This study was performed to determine the antibiotic resistance pattern, biofilm formation, and frequency of biofilm-related genes in P. aeruginosa strains. In total, 123 P. aeruginosa isolates were collected from different clinical sources. Antimicrobial susceptibility testing (AST) was performed to detect multidrug-resistant P. aeruginosa (MDRPA) isolates. To evaluate the biofilm-forming isolates, the microtiter plate (MTP) method was carried out. Also, the prevalence of biofilm genotype patterns, including pslA, pslD, pelA, pelF, and algD genes, was detected by polymerases chain reaction (PCR). According to our findings, the highest resistance and susceptibility rates were found in ceftazidime with 74.7% (n = 92) and ciprofloxacin with 42.2% (n = 52), respectively. In our study, the highest level of antibiotic resistance belonged to wound isolates which meropenem had the most antibacterial activity against them. In total, 86.1% (n = 106) P. aeruginosa isolates were determined as MDRPA, of which 61.3% (n = 65) were able to form strong biofilm. The highest and lowest frequency of biofilm-related genes among biofilm producer isolates belonged to pelF with 82.1% (n = 101) and algD with 55.2% (n = 68), respectively. The findings of the conducted study indicate a significant relationship between MDRPA and biofilm genotypic/phenotypic patterns, suggesting the necessity of a careful surveillance program in hospital settings.}, } @article {pmid38016564, year = {2023}, author = {Nguyen, VT and Le, VA and Do, QH and Le, TN and Vo, TD}, title = {Emerging revolving algae biofilm system for algal biomass production and nutrient recovery from wastewater.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {168911}, doi = {10.1016/j.scitotenv.2023.168911}, pmid = {38016564}, issn = {1879-1026}, abstract = {Toward the direction of zero‑carbon emission and green technologies for wastewater treatment, algae-based technologies are considered promising candidates to deal with the current situation of pollution and climate change. Recent developments of algae-based technologies have been introduced in previous studies in which their performances were optimized for wastewater treatment and biomass production. Among these, revolving algae biofilm (RAB) reactors have been proven to have a great potential in high biomass productivity, simple harvesting method, great CO2 transfer rate, high light-use efficiency, heavy metal capture, nutrient removal, and acid mine drainage treatment in previous studies. However, there were few articles detailing RAB performance, which concealed its enormous potential and diminished interest in the model. Hence, this review aims to reveal the major benefit of RAB reactors in simultaneous wastewater treatment and biomass cultivation. However, there is still a lack of research on aspects to upgrade this technology which requires further investigations to improve performance or fulfill the concept of circular economy.}, } @article {pmid38015101, year = {2023}, author = {Klopper, KB and Bester, E and van Schalkwyk, M and Wolfaardt, GM}, title = {Highlighting the limitations of static microplate biofilm assays for industrial biocide effectiveness compared to dynamic flow conditions.}, journal = {Environmental microbiology reports}, volume = {}, number = {}, pages = {}, doi = {10.1111/1758-2229.13214}, pmid = {38015101}, issn = {1758-2229}, support = {//Ekurhuleni Water Care Company (ERWAT) Research Chair in Water Management/ ; }, abstract = {The minimal inhibitory concentration of an antimicrobial required to inhibit the growth of planktonic populations (minimum inhibitory concentration [MIC]) remains the 'gold standard' even though biofilms are acknowledged to be recalcitrant to concentrations that greatly exceed the MIC. As a result, most studies focus on biofilm tolerance to high antimicrobial concentrations, whereas the effect of environmentally relevant sub-MIC on biofilms is neglected. The effect of the MIC and sub-MIC of an isothiazolinone biocide on a microbial community isolated from an industrial cooling system was assessed under static and flow conditions. The differential response of planktonic and sessile populations to these biocide concentrations was discerned by modifying the broth microdilution assay. However, the end-point analysis of biofilms cultivated in static microplates obscured the effect of sub-MIC and MIC on biofilms. A transition from batch to the continuous flow system revealed a more nuanced response of biofilms to these biocide concentrations, where biofilm-derived planktonic cell production was maintained despite an increase in the frequency and extent of biofilm sloughing. A holistic, 'best of both worlds' approach that combines the use of static and continuous flow systems is useful to investigate the potential for the development of persistent biofilms under conditions where exposure to sub-MIC and MIC may occur.}, } @article {pmid38014955, year = {2023}, author = {Kalia, M and Amari, D and Davies, DG and Sauer, K}, title = {cis-DA-dependent dispersion by Pseudomonas aeruginosa biofilm and identification of cis-DA-sensory protein DspS.}, journal = {mBio}, volume = {}, number = {}, pages = {e0257023}, doi = {10.1128/mbio.02570-23}, pmid = {38014955}, issn = {2150-7511}, abstract = {Dispersion is an essential stage of the biofilm life cycle resulting in the release of bacteria from a biofilm into the surrounding environment. Dispersion contributes to bacterial survival by relieving overcrowding within a biofilm and allowing dissemination of cells into new habitats for colonization. Thus, dispersion can contribute to biofilm survival as well as disease progression and transmission. Cells dispersed from a biofilm rapidly lose their recalcitrant antimicrobial-tolerant biofilm phenotype and transition to a state that is susceptible to antibiotics. However, much of what is known about this biofilm developmental stage has been inferred from exogenously induced dispersion. Our findings provide the first evidence that native dispersion is coincident with reduced cyclic dimeric guanosine monophosphate levels, while also relying on at least some of the same factors that are central to the environmentally induced dispersion response, namely, BdlA, DipA, RbdA, and AmrZ. Additionally, we demonstrate for the first time that cis-DA signaling to induce dispersion is attributed to the two-component sensor/response regulator DspS, a homolog of the DSF sensor RpfC. Our findings also provide a path toward manipulating the native dispersion response as a novel and highly promising therapeutic intervention.}, } @article {pmid38014264, year = {2023}, author = {Greenwich, JL and Eagan, JL and Feirer, N and Boswinkle, K and Minasov, G and Shuvalova, L and Inniss, NL and Raghavaiah, J and Ghosh, AK and Satchell, KJF and Allen, KD and Fuqua, C}, title = {Control of Biofilm Formation by an Agrobacterium tumefaciens Pterin-Binding Periplasmic Protein Conserved Among Pathogenic Bacteria.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.11.18.567607}, pmid = {38014264}, abstract = {UNLABELLED: Biofilm formation and surface attachment in multiple Alphaproteobacteria is driven by unipolar polysaccharide (UPP) adhesins. The pathogen Agrobacterium tumefaciens produces a UPP adhesin, which is regulated by the intracellular second messenger cyclic diguanylate monophosphate (cdGMP). Prior studies revealed that DcpA, a diguanylate cyclase-phosphodiesterase (DGC-PDE), is crucial in control of UPP production and surface attachment. DcpA is regulated by PruR, a protein with distant similarity to enzymatic domains known to coordinate the molybdopterin cofactor (MoCo). Pterins are bicyclic nitrogen-rich compounds, several of which are formed via a non-essential branch of the folate biosynthesis pathway, distinct from MoCo. The pterin-binding protein PruR controls DcpA activity, fostering cdGMP breakdown and dampening its synthesis. Pterins are excreted and we report here that PruR associates with these metabolites in the periplasm, promoting interaction with the DcpA periplasmic domain. The pteridine reductase PruA, which reduces specific dihydro-pterin molecules to their tetrahydro forms, imparts control over DcpA activity through PruR. Tetrahydromonapterin preferentially associates with PruR relative to other related pterins, and the PruR-DcpA interaction is decreased in a pruA mutant. PruR and DcpA are encoded in an operon that is conserved amongst multiple Proteobacteria including mammalian pathogens. Crystal structures reveal that PruR and several orthologs adopt a conserved fold, with a pterin-specific binding cleft that coordinates the bicyclic pterin ring. These findings define a new pterin-responsive regulatory mechanism that controls biofilm formation and related cdGMP-dependent phenotypes in A. tumefaciens and is found in multiple additional bacterial pathogens.

SIGNIFICANCE: Biofilms are bacterial communities attached to surfaces, physiologically distinct from free-living cells, and a common cause of persistent infections. Here we define the mechanism of a novel biofilm regulatory system based on excreted metabolites called pterins, that is conserved within a wide range of Gram-negative bacteria, including multiple pathogens of animals and plants. The molecular mechanism of pterin-dependent regulation is reported including structural determination of several members of a new family of pterin-binding proteins. Pterins are produced across all domains of life and mechanistic insights into this regulatory circuit could lead to new advances in antibiofilm treatments.}, } @article {pmid38013123, year = {2023}, author = {Alhajj, N and Yahya, MFZR and O'Reilly, NJ and Cathcart, H}, title = {Development and characterization of a spray-dried inhalable ternary combination for the treatment of Pseudomonas aeruginosa biofilm infection in cystic fibrosis.}, journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences}, volume = {}, number = {}, pages = {106654}, doi = {10.1016/j.ejps.2023.106654}, pmid = {38013123}, issn = {1879-0720}, abstract = {Cystic fibrosis (CF) is an inherited lung disease characterised by the accumulation of thick layers of dried mucus in the lungs which serve as a nidus for chronic infection. Pseudomonas aeruginosa is the predominant cause of chronic lung infection in cystic fibrosis. The dense mucus coupled with biofilm formation hinder antibiotic penetration and prevent them from reaching their target. Mucoactive agents are recommended in the treatment of CF in combination with antibiotics. In spite of the extensive research in developing novel drug combinations for the treatment of lung infection in CF, to our knowledge, there is no study that combines antibiotic, antibiofilm and mucoactive agent in a single inhaled dry powder formulation. In the present study, we investigate the possibility of adding a mucoactive agent to our previously developed ciprofloxacinquercetin (antibiotic-antibiofilm) dry powder for inhalation. Three mucoactive agents, namely mannitol (MAN), N-acetyl-L-cysteine (NAC) and ambroxol hydrochloride (AMB), were investigated for this purpose. The ternary combinations were prepared via spray drying without the addition of excipients. All ternary combinations conserved or improved the antibacterial and biofilm inhibition activities of ciprofloxacin against P. aeruginosa (ATCC 10145). The addition of AMB resulted in an amorphous ternary combination (SD-CQA) with superior physical stability as indicated by DSC and nonambient XRPD. Furthermore, SD-CQA displayed better in vitro aerosolization performance (ED ∼ 71%; FPF ∼ 49%) compared to formulations containing MAN and NAC (ED ∼ 64% and 44%; FPF ∼ 44% and 29%, respectively). In conclusion, a ternary drug combination powder with suitable aerosolization, physical stability and antibacterial/antibiofilm properties was prepared by a single spray drying step.}, } @article {pmid38009922, year = {2023}, author = {Tsitouras, A and Al-Ghussain, N and Butcher, J and Stintzi, A and Delatolla, R}, title = {The microbiome of two strategies for ammonia removal with the sequencing batch moving bed biofilm reactor treating cheese production wastewater.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0150723}, doi = {10.1128/aem.01507-23}, pmid = {38009922}, issn = {1098-5336}, abstract = {Cheese production facilities must abide by sewage discharge bylaws that prevent overloading municipal water resource recovery facilities, eutrophication, and toxicity to aquatic life. Compact treatment systems can permit on-site treatment of cheese production wastewater; however, competition between heterotrophs and nitrifiers impedes the implementation of the sequencing batch moving bed biofilm reactor (SB-MBBR) for nitrification from high-carbon wastewaters. This study demonstrates that a single SB-MBBR is not feasible for nitrification when operated with anerobic and aerobic cycling for carbon and phosphorous removal from cheese production wastewater, as nitrification does not occur in a single reactor. Thus, two reactors in series are recommended to achieve nitrification from cheese production wastewater in SB-MBBRs. These findings can be applied to pilot and full-scale SB-MBBR operations. By demonstrating the potential to implement partial nitrification in the SB-MBBR system, this study presents the possibility of implementing partial nitrification in the SB-MBBR, resulting in the potential for more sustainable treatment of nitrogen from cheese production wastewater.}, } @article {pmid38009640, year = {2023}, author = {Behera, S and Mumtaz, S and Singh, M and Mukhopadhyay, K}, title = {Synergistic Potential of α-Melanocyte Stimulating Hormone Based Analogues with Conventional Antibiotic against Planktonic, Biofilm-Embedded, and Systemic Infection Model of MRSA.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00298}, pmid = {38009640}, issn = {2373-8227}, abstract = {The repotentiation of the existing antibiotics by exploiting the combinatorial potential of antimicrobial peptides (AMPs) with them is a promising approach to address the challenges of slow antibiotic development and rising antimicrobial resistance. In the current study, we explored the ability of lead second generation Ana-peptides viz. Ana-9 and Ana-10, derived from Alpha-Melanocyte Stimulating Hormone (α-MSH), to act synergistically with different classes of conventional antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). The peptides exhibited prominent synergy with β-lactam antibiotics, namely, oxacillin, ampicillin, and cephalothin, against planktonic MRSA. Furthermore, the lead combination of Ana-9/Ana-10 with oxacillin provided synergistic activity against clinical MRSA isolates. Though the treatment of MRSA is complicated by biofilms, the lead combinations successfully inhibited biofilm formation and also demonstrated biofilm disruption potential. Encouragingly, the peptides alone and in combination were able to elicit in vivo anti-MRSA activity and reduce the bacterial load in the liver and kidney of immune-compromised mice. Importantly, the presence of Ana-peptides at sub-MIC doses slowed the resistance development against oxacillin in MRSA cells. Thus, this study highlights the synergistic activity of Ana-peptides with oxacillin advocating for the potential of Ana-peptides as an alternative therapeutic and could pave the way for the reintroduction of less potent conventional antibiotics into clinical use against MRSA infections.}, } @article {pmid38008320, year = {2023}, author = {Doose, C and Hubas, C}, title = {The metabolites of light: Untargeted metabolomic approaches bring new clues to understand light-driven acclimation of intertidal mudflat biofilm.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {168692}, doi = {10.1016/j.scitotenv.2023.168692}, pmid = {38008320}, issn = {1879-1026}, abstract = {The microphytobenthos (MPB), a microbial community of primary producers, play a key role in coastal ecosystem functioning, particularly in intertidal mudflats. These mudflats experience challenging variations of irradiance, forcing the micro-organisms to develop photoprotective mechanisms to survive and thrive in this dynamic environment. Two major adaptations to light are well described in literature: the excess of light energy dissipation through non-photochemical quenching (NPQ), and the vertical migration in the sediment. These mechanisms trigger considerable scientific interest, but the biological processes and metabolic mechanisms involved in light-driven vertical migration remain largely unknown. To our knowledge, this study investigates for the first time metabolomic responses of a migrational mudflat biofilm exposed for 30 min to a light gradient of photosynthetically active radiation (PAR) from 50 to 1000 μmol photons m[-2] s[-1]. The untargeted metabolomic analysis allowed to identify metabolites involved in two types of responses to light irradiance levels. On the one hand, the production of SFAs and MUFAs, primarily derived from bacteria, indicates a healthy photosynthetic state of MPB under low light (LL; 50 and 100 PAR) and medium light (ML; 250 PAR) conditions. Conversely, when exposed to high light (HL; 500, 750 and 1000 PAR), the MPB experienced light-induced stress, triggering the production of alka(e)nes and fatty alcohols. The physiological and ecological roles of these compounds are poorly described in literature. This study sheds new light on the topic, as it suggests that these compounds may play a crucial and previously unexplored role in light-induced stress acclimation of migrational MPB biofilms. Since alka(e)nes are produced from FAs decarboxylation, these results thus emphasize for the first time the importance of FAs pathways in microphytobenthic biofilms acclimation to light.}, } @article {pmid38008233, year = {2023}, author = {Liang, S and Xiao, L and Fang, Y and Chen, T and Xie, Y and Peng, Z and Wu, M and Liu, Y and Xie, J and Nie, Y and Zhao, X and Deng, Y and Zhao, C and Mai, Y}, title = {A nanocomposite hydrogel for co-delivery of multiple anti-biofilm therapeutics to enhance the treatment of bacterial biofilm-related infections.}, journal = {International journal of pharmaceutics}, volume = {}, number = {}, pages = {123638}, doi = {10.1016/j.ijpharm.2023.123638}, pmid = {38008233}, issn = {1873-3476}, abstract = {The characteristics of biofilms have exacerbated the issue of clinical antibiotic resistance, rendering it a pressing challenge in need of resolution. The combination of biofilm-dispersing agents and antibiotics can eliminate biofilms and promote healing synergistically in infected wounds. In this study, we developed a novel nanocomposite hydrogel (NC gel) comprised of the poly(lactic acid)-hyperbranched polyglycerol (PLA-HPG) based bioadhesive nanoparticles (BNPs) and a hydrophilic carboxymethyl chitosan (CS) network. The NC gel was designed to co-deliver two biofilm-dispersing agents (an NO-donor SNO, and an α-amylase Am) and an antibiotic, cefepime (Cef), utilizing a synergistic anti-biofilm mechanism in which Am loosens the matrix structure and NO promotes the release of biofilm bacteria via quorum sensing, and Cef kills bacteria. The drug-loaded NC gels (SNO/BNP/CS@Am-Cef) demonstrated sustained drug release, minimal cytotoxicity, and increased drug-bacterial interactions at the site of infection. When applied to mice infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilms in vivo, SNO/BNP/CS@Am-Cef enhanced biofilm elimination and promoted wound healing compared to traditional antibiotic treatments. Our work demonstrates the feasibility of the co-delivery of biofilm-dispersing agents and antibiotics using the NC gel and presents a promising approach for the polytherapy of bacterial biofilm-related infections.}, } @article {pmid38007896, year = {2023}, author = {Wu, C and Zhou, J and Pang, S and Yang, L and Lichtfouse, E and Liu, H and Xia, S and Rittmann, BE}, title = {Reduction and precipitation of chromium(VI) using a palladized membrane biofilm reactor.}, journal = {Water research}, volume = {249}, number = {}, pages = {120878}, doi = {10.1016/j.watres.2023.120878}, pmid = {38007896}, issn = {1879-2448}, abstract = {H2-driven reduction of hexavalent chromium (Cr(VI)) using precious-metal catalysts is promising, but its implementation in water treatment has been restricted by poor H2-transfer efficiency and high catalyst loss. We investigated the reduction of Cr(VI) through hydrogenation catalyzed by elemental-palladium nanoparticles (PdNPs) generated in-situ within biofilm of a membrane biofilm reactor (MBfR), creating a Pd-MBfR. Experiments were conducted using a Pd-MBfR and a non-Pd MBfR. The Pd-MBfR achieved Cr(VI) (1000 μg L[-1]) reduction of >99 % and reduced the concentration of total Cr to below 50 μg L[-1], much lower than the total Cr concentration in the non-Pd MBfR effluent (290 μg L[-1]). The Pd-MBfR also had a lower concentration of dissolved organic compounds compared to the non-Pd MBfR, which minimized the formation of soluble organo-Cr(III) complexes and promoted precipitation of Cr(OH)3. Solid-state characterizations documented deposition of Cr(OH)3 as the product of Cr(VI) reduction in the Pd-MBfR. Metagenomic analyses revealed that the addition and reduction of Cr(VI) had minimal impact on the microbial community (dominated by Dechloromonas) and functional genes in the biofilm of the Pd-MBfR, since the PdNP-catalyzed reduction process was rapid. This study documented efficient Cr(VI) reduction and precipitation of Cr(OH)3 by the Pd-MBfR technology.}, } @article {pmid38006347, year = {2023}, author = {Gautam, D and Dolma, KG and Khandelwal, B and Goyal, RK and Mitsuwan, W and Pereira, MLG and Klangbud, WK and Gupta, M and Wilairatana, P and Siyadatpanah, A and Wiart, C and Nissapatorn, V}, title = {Acinetobacter baumannii in suspected bacterial infections: Association between multidrug resistance, virulence genes, & biofilm production.}, journal = {The Indian journal of medical research}, volume = {158}, number = {4}, pages = {439-446}, doi = {10.4103/ijmr.ijmr_3470_21}, pmid = {38006347}, issn = {0971-5916}, abstract = {BACKGROUND OBJECTIVES: Acinetobacter baumannii has emerged as a nosocomial pathogen with a tendency of high antibiotic resistance and biofilm production. This study aimed to determine the occurrence of A. baumannii from different clinical specimens of suspected bacterial infections and furthermore to see the association of biofilm production with multidrug resistance and expression of virulence factor genes in A. baumannii.

METHODS: A. baumannii was confirmed in clinical specimens by the detection of the blaOXA-51-like gene. Biofilm production was tested by microtitre plate assay and virulence genes were detected by real-time PCR.

RESULTS: A. baumannii was isolated from a total of 307 clinical specimens. The isolate which showed the highest number of A. baumannii was an endotracheal tube specimen (44.95%), then sputum (19.54%), followed by pus (17.26%), urine (7.49%) and blood (5.86%), and <2 per cent from body fluids, catheter-tips and urogenital specimens. A resistance rate of 70-81.43 per cent against all antibiotics tested, except colistin and tigecycline, was noted, and 242 (78.82%) isolates were multidrug-resistant (MDR). Biofilm was detected in 205 (66.78%) with a distribution of 54.1 per cent weak, 10.42 per cent medium and 2.28 per cent strong biofilms. 71.07 per cent of MDR isolates produce biofilm (P<0.05). Amongst virulence factor genes, 281 (91.53%) outer membrane protein A (OmpA) and 98 (31.92%) biofilm-associated protein (Bap) were detected. Amongst 100 carbapenem-resistant A. baumannii, the blaOXA-23-like gene was predominant (96%), the blaOXA-58-like gene (6%) and none harboured the blaOXA-24-like gene. The metallo-β-lactamase genes blaIMP-1 (4%) and blaVIM-1(8%) were detected, and 76 per cent showed the insertion sequence ISAba1.

INTERPRETATION CONCLUSIONS: The majority of isolates studied were from lower respiratory tract specimens. The high MDR rate and its positive association with biofilm formation indicate the nosocomial distribution of A. baumannii. The biofilm formation and the presence of Bap were not interrelated, indicating that biofilm formation was not regulated by a single factor. The MDR rate and the presence of OmpA and Bap showed a positive association (P<0.05). The isolates co-harbouring different carbapenem resistance genes were the predominant biofilm producers, which will seriously limit the therapeutic options suggesting the need for strict antimicrobial stewardship and molecular surveillance in hospitals.}, } @article {pmid38004737, year = {2023}, author = {Cai, T and Tang, H and Du, X and Wang, W and Tang, K and Wang, X and Liu, D and Wang, P}, title = {Genomic Island-Encoded Diguanylate Cyclase from Vibrio alginolyticus Regulates Biofilm Formation and Motility in Pseudoalteromonas.}, journal = {Microorganisms}, volume = {11}, number = {11}, pages = {}, pmid = {38004737}, issn = {2076-2607}, support = {42188102, 91951203 and 32070175//the National Science Foundation of China/ ; 2022YFC3103600//the National Key R&D Program of China/ ; 2021345//the Youth Innovation Promotion Association CAS/ ; 2019BT02Y262//the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program/ ; GJTD-2020-12//the K. C. Wong Education Foundation/ ; 2021B1212050023//the Science and Technology Planning Project of Guangdong Province of China/ ; }, abstract = {Many bacteria use the second messenger c-di-GMP to regulate exopolysaccharide production, biofilm formation, motility, virulence, and other phenotypes. The c-di-GMP level is controlled by the complex network of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) that synthesize and degrade c-di-GMP. In addition to chromosomally encoded DGCs, increasing numbers of DGCs were found to be located on mobile genetic elements. Whether these mobile genetic element-encoded DGCs can modulate the physiological phenotypes in recipient bacteria after horizontal gene transfer should be investigated. In our previous study, a genomic island encoding three DGC proteins (Dgc137, Dgc139, and Dgc140) was characterized in Vibrio alginolyticus isolated from the gastric cavity of the coral Galaxea fascicularis. Here, the effect of the three DGCs in four Pseudoalteromonas strains isolated from coral Galaxea fascicularis and other marine environments was explored. The results showed that when dgc137 is present rather than the three DGC genes, it obviously modulates biofilm formation and bacterial motility in these Pseudoalteromonas strains. Our findings implied that mobile genetic element-encoded DGC could regulate the physiological status of neighboring bacteria in a microbial community by modulating the c-di-GMP level after horizontal gene transfer.}, } @article {pmid38004605, year = {2023}, author = {Shahi Ardakani, A and Afrasiabi, S and Sarraf, P and Benedicenti, S and Solimei, L and Chiniforush, N}, title = {In Vitro Assessment of SWEEPS and Antimicrobial Photodynamic Therapy Alone or in Combination for Eradicating Enterococcus faecalis Biofilm in Root Canals.}, journal = {Pharmaceutics}, volume = {15}, number = {11}, pages = {}, pmid = {38004605}, issn = {1999-4923}, abstract = {OBJECTIVES: This study investigates the efficacy of antimicrobial photodynamic therapy (aPDT) using riboflavin and a blue diode laser (BDL), combined with shock wave-enhanced emission photoacoustic streaming (SWEEPS), against Enterococcus faecalis.

MATERIALS AND METHODS: A total of 48 extracted single-rooted human teeth were used. The root canals were instrumented, sealed at their apices, had the smear layer removed, and then underwent autoclave sterilization. Subsequently, each canal was inoculated with E. faecalis bacterial suspension and allowed to incubate for ten days. After confirming the presence of biofilms through scanning electron microscopy (SEM) in three teeth, the remaining teeth were randomly allocated into nine groups, each containing five teeth: control, 5.25% sodium hypochlorite (NaOCl), BDL, SWEEPS + normal saline, SWEEPS + NaOCl, riboflavin, riboflavin + SWEEPS, riboflavin + BDL, and riboflavin + BDL + SWEEPS. After the treatment, the numbers of colony-forming units (CFUs)/mL were calculated. The data were analysed using one-way ANOVA followed by Tukey's test for comparisons.

RESULTS: All groups, with the exception of the BDL group, exhibited a significant reduction in E. faecalis CFU/mL when compared to the control group (p < 0.001). The difference in CFU/mL value between riboflavin + BDL + SWEEPS and riboflavin + SWEEPS was significant (p = 0.029), whereas there was no significant difference between riboflavin + BDL + SWEEPS and riboflavin + BDL (p = 0.397). Moreover, there was no statistically significant difference between the riboflavin + SWEEPS group and the riboflavin + BDL group (p = 0.893).

CONCLUSIONS: The results demonstrated that combining the SWEEPS technique with riboflavin as a photosensitizer activated by BDL in aPDT effectively reduced the presence of E. faecalis in root canals.}, } @article {pmid38004561, year = {2023}, author = {Guo, Y and Mao, Z and Ran, F and Sun, J and Zhang, J and Chai, G and Wang, J}, title = {Nanotechnology-Based Drug Delivery Systems to Control Bacterial-Biofilm-Associated Lung Infections.}, journal = {Pharmaceutics}, volume = {15}, number = {11}, pages = {}, doi = {10.3390/pharmaceutics15112582}, pmid = {38004561}, issn = {1999-4923}, support = {SKLRD-OP-202302//Open Project of State Key Laboratory of Respiratory Disease/ ; A2023090//Medical Scientific Research Foundation of Guangdong Province/ ; 2023A1515011064//Guangdong Basic and Applied Basic Research Foundation/ ; 22qntd4503//Fundamental Research Funds for the Central Universities/ ; 2019E10020 (KFJJ-202202)//Open Project of The Key Laboratory of Diagnosis and Treatment of Digestive System Tumors of Zhejiang Province/ ; }, abstract = {Airway mucus dysfunction and impaired immunological defenses are hallmarks of several lung diseases, including asthma, cystic fibrosis, and chronic obstructive pulmonary diseases, and are mostly causative factors in bacterial-biofilm-associated respiratory tract infections. Bacteria residing within the biofilm architecture pose a complex challenge in clinical settings due to their increased tolerance to currently available antibiotics and host immune responses, resulting in chronic infections with high recalcitrance and high rates of morbidity and mortality. To address these unmet clinical needs, potential anti-biofilm therapeutic strategies are being developed to effectively control bacterial biofilm. This review focuses on recent advances in the development and application of nanoparticulate drug delivery systems for the treatment of biofilm-associated respiratory tract infections, especially addressing the respiratory barriers of concern for biofilm accessibility and the various types of nanoparticles used to combat biofilms. Understanding the obstacles facing pulmonary drug delivery to bacterial biofilms and nanoparticle-based approaches to combatting biofilm may encourage researchers to explore promising treatment modalities for bacterial-biofilm-associated chronic lung infections.}, } @article {pmid38004397, year = {2023}, author = {Bonincontro, G and Scuderi, SA and Marino, A and Simonetti, G}, title = {Synergistic Effect of Plant Compounds in Combination with Conventional Antimicrobials against Biofilm of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida spp.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {11}, pages = {}, doi = {10.3390/ph16111531}, pmid = {38004397}, issn = {1424-8247}, abstract = {Bacterial and fungal biofilm has increased antibiotic resistance and plays an essential role in many persistent diseases. Biofilm-associated chronic infections are difficult to treat and reduce the efficacy of medical devices. This global problem has prompted extensive research to find alternative strategies to fight microbial chronic infections. Plant bioactive metabolites with antibiofilm activity are known to be potential resources to alleviate this problem. The phytochemical screening of some medicinal plants showed different active groups, such as stilbenes, tannins, alkaloids, terpenes, polyphenolics, flavonoids, lignans, quinones, and coumarins. Synergistic effects can be observed in the interaction between plant compounds and conventional drugs. This review analyses and summarises the current knowledge on the synergistic effects of plant metabolites in combination with conventional antimicrobials against biofilms of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The synergism of conventional antimicrobials with plant compounds can modify and inhibit the mechanisms of acquired resistance, reduce undesirable effects, and obtain an appropriate therapeutic effect at lower doses. A deeper knowledge of these combinations and of their possible antibiofilm targets is needed to develop next-generation novel antimicrobials and/or improve current antimicrobials to fight drug-resistant infections attributed to biofilm.}, } @article {pmid38002255, year = {2023}, author = {Soltane, R and Alasiri, A and Taha, MN and Abd El-Aleam, RH and Alghamdi, KS and Ghareeb, MA and Keshek, DE and Cardoso, SM and Sayed, AM}, title = {Norlobaridone Inhibits Quorum Sensing-Dependent Biofilm Formation and Some Virulence Factors in Pseudomonas aeruginosa by Disrupting Its Transcriptional Activator Protein LasR Dimerization.}, journal = {Biomolecules}, volume = {13}, number = {11}, pages = {}, doi = {10.3390/biom13111573}, pmid = {38002255}, issn = {2218-273X}, support = {IFP22UQU4331312DSR029//Deputyship for Research & Innovation, Ministry of Education/ ; }, abstract = {In the present study, norlobaridone (NBD) was isolated from Parmotrema and then evaluated as a new potent quorum sensing (QS) inhibitor against Pseudomonas aeruginosa biofilm development. This phenolic natural product was found to reduce P. aeruginosa biofilm formation (64.6% inhibition) and its related virulence factors, such as pyocyanin and rhamnolipids (% inhibition = 61.1% and 55%, respectively). In vitro assays inhibitory effects against a number of known LuxR-type receptors revealed that NBD was able to specifically block P. aeruginosa's LasR in a dose-dependent manner. Further molecular studies (e.g., sedimentation velocity and thermal shift assays) demonstrated that NBD destabilized LasR upon binding and damaged its functional quaternary structure (i.e., the functional dimeric form). The use of modelling and molecular dynamics (MD) simulations also allowed us to further understand its interaction with LasR, and how this can disrupt its dimeric form. Finally, our findings show that NBD is a powerful and specific LasR antagonist that should be widely employed as a chemical probe in QS of P. aeruginosa, providing new insights into LasR antagonism processes. The new discoveries shed light on the mysterious world of LuxR-type QS in this key opportunistic pathogen.}, } @article {pmid38002242, year = {2023}, author = {Priya, GB and Srinivas, K and Shilla, H and Milton, AAP}, title = {High Prevalence of Multidrug-Resistant, Biofilm-Forming Virulent Clostridium perfringens in Broiler Chicken Retail Points in Northeast India.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {22}, pages = {}, doi = {10.3390/foods12224185}, pmid = {38002242}, issn = {2304-8158}, abstract = {In light of the significant public health and food safety implications associated with Clostridium perfringens, this study aimed to isolate and characterize C. perfringens in samples obtained from broiler chicken retail points in Meghalaya, northeastern India. A total of 280 samples comprising meat, intestinal contents, water, and hand swabs were processed to detect contamination by C. perfringens. The isolates were subjected to toxinotyping, antimicrobial susceptibility testing, and biofilm-forming ability test. The overall occurrence of C. perfringens was 22.5% (17.74-27.85, 95% CI) with the highest recovery from intestine samples (31%; 22.13-41.03, 95% CI), followed by meat (23%, 15.17-32.49, 95% CI) and water samples (18%, 8.58-31.44, 95% CI). Type A was the predominant toxinotype (71.43%, 58.65-82.11, 95% CI), followed by Type A with beta2 toxin (17.46%, 9.05-29.10, 95% CI), Type C (7.94%, 2.63-17.56, 95% CI), and Type C with beta2 toxin (3.17%, 0.39-11.0, 95% CI). Nearly all (95.24%) isolates were multidrug resistant and 68.25% were biofilm formers. The predominance of multidrug-resistant and virulent Type A and Type C C. perfringens in retail broiler meat and intestines in the tribal-dominated northeastern region of India is of great concern from food safety and public health perspectives.}, } @article {pmid38001054, year = {2023}, author = {Alvira-Arill, GR and Willems, HME and Fortwendel, JP and Yarbrough, A and Tansmore, J and Sierra, CM and Bashqoy, F and Stultz, JS and Peters, BM}, title = {Impact of intravenous fat emulsion choice on Candida biofilm, hyphal growth, and catheter-related bloodstream infections in pediatric patients.}, journal = {The Journal of infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1093/infdis/jiad527}, pmid = {38001054}, issn = {1537-6613}, abstract = {BACKGROUND: Use of mixed-oil intravenous fat emulsion (MO-IFE) was shown to inhibit C. albicans biofilm formation and overall rate of catheter-related bloodstream infections (CR-BSIs) compared to soybean-oil IFE (SO-IFE). We aimed to delineate this inhibitory mechanism and impact of IFE choice on distribution of fungal CR-BSIs.

METHODS: Transcriptional profiling was conducted on C. albicans grown in SO-IFE, MO-IFE, or SO-IFE+capric acid. Overexpression strains of shared downregulated genes were constructed using a tetracycline-off system to assess hypha and biofilm formation in IFEs. A 5-year retrospective multi-center cohort study was performed to assess differences in CR-BSIs caused by Candida species based on IFE formulation received in pediatric patients.

RESULTS: Genes significantly downregulated in MO-IFE and SO-IFE+capric acid included CDC11, HGC1, and UME6. Overexpression of HGC1 or UME6 enabled filamentation in capric acid and MO-IFE. Interestingly, only overexpression of UME6 was sufficient to rescue biofilm growth in MO-IFE. MO-IFE administration was associated with a higher proportion of non-albicans Candida vs. C. albicans CR-BSIs (42% vs 33%; OR 1.22, 95% CI 0.46 to 3.26).

CONCLUSIONS: MO-IFE impacts C. albicans biofilm formation and hyphal growth via a UME6-dependent mechanism. A numerical, but not statistically significant difference in distribution of Candida spp. among CR-BSIs was observed.}, } @article {pmid38001486, year = {2023}, author = {Wang, X and Zhang, C and He, L and Li, M and Chen, P and Yang, W and Sun, P and Li, D and Zhang, Y}, title = {Near infrared II excitation nanoplatform for photothermal/chemodynamic/antibiotic synergistic therapy combating bacterial biofilm infections.}, journal = {Journal of nanobiotechnology}, volume = {21}, number = {1}, pages = {446}, pmid = {38001486}, issn = {1477-3155}, support = {82102588//National Natural Science Foundation of China/ ; 232300421050//Natural Science Foundation of Henan Province/ ; 222300420072//Natural Science Foundation of Henan Province/ ; }, abstract = {Drug-resistant bacterial biofilm infections (BBIs) are refractory to elimination. Near-infrared-II photothermal therapy (NIR-II PTT) and chemodynamic therapy (CDT) are emerging antibiofilm approaches because of the heavy damage they inflict upon bacterial membrane structures and minimal drug-resistance. Hence, synergistic NIR-II PTT and CDT hold great promise for enhancing the therapeutic efficacy of BBIs. Herein, we propose a biofilm microenvironment (BME)-responsive nanoplatform, BTFB@Fe@Van, for use in the synergistic NIR-II PTT/CDT/antibiotic treatment of BBIs. BTFB@Fe@Van was prepared through the self-assembly of phenylboronic acid (PBA)-modified small-molecule BTFB, vancomycin, and the CDT catalyst Fe[2+] ions in DSPE-PEG2000. Vancomycin was conjugated with BTFB through a pH-sensitive PBA-diol interaction, while the Fe[2+] ions were bonded to the sulfur and nitrogen atoms of BTFB. The PBA-diol bonds decomposed in the acidic BME, simultaneously freeing the vancomycin and Fe[2+] irons. Subsequently, the catalytic product hydroxyl radical was generated by the Fe[2+] ions in the oxidative BME overexpressed with H2O2. Moreover, under 1064 nm laser, BTFB@Fe@Van exhibited outstanding hyperthermia and accelerated the release rate of vancomycin and the efficacy of CDT. Furthermore, the BTFB@Fe@Van nanoplatform enabled the precise NIR-II imaging of the infected sites. Both in-vitro and in-vivo experiments demonstrated that BTFB@Fe@Van possesses a synergistic NIR-II PTT/CDT/antibiotic mechanism against BBIs.}, } @article {pmid37999802, year = {2023}, author = {Rao, PD and Sandeep, AH and Madhubala, MM and Mahalaxmi, S}, title = {Comparative evaluation of effect of nisin-incorporated ethylenediamine tetraacetic acid and MTAD on endodontic biofilm eradication, smear layer removal, and depth of sealer penetration.}, journal = {Clinical oral investigations}, volume = {}, number = {}, pages = {}, pmid = {37999802}, issn = {1436-3771}, abstract = {OBJECTIVES: To comparatively evaluate the nisin-incorporated ethylenediamine tetraacetic acid (N-EDTA) and MTAD on cytotoxicity, endodontic biofilm eradication potential, smear layer removal ability, and sealer penetration depth.

MATERIALS AND METHODS: N-EDTA was prepared and characterized using high-performance liquid chromatography (HPLC). Minimum inhibitory, minimum bactericidal, and minimum biofilm inhibitory concentration (MBC, MIC, and MBIC) were determined on Enterococcus faecalis (E. faecalis) strain. The cytocompatibility of N-EDTA and MTAD was evaluated using 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based colorimetric assay. Dentin specimens (n = 88 for antibacterial analysis, n = 170 for sealer penetration depth) were prepared and subjected to the classical irrigating strategy and obturation, respectively. The scanning electron microscopic evaluation (SEM) was done for the evaluation of biofilm disruption and smear layer removal. Confocal laser scanning microscopy (CLSM) evaluation was done for determining percentage of bacterial viability and sealer penetration depth. Statistical analysis of one-way ANOVA and Tukey's HSD post hoc tests for bacterial viability and Kruskal-Wallis test and Mann-Whitney test for smear layer removal and depth of penetration were done with the significance level set at p < 0.05.

RESULTS: MTAD and N-EDTA showed cytocompatibility without any statistical differences from each other. For N-EDTA, the MIC and MBC values were 12.5 μg/ml (1:8), and MBIC values were 36 μg/ml. Biofilm disruption and killed bacterial percentage of N-EDTA was statistically higher than MTAD, whereas both the materials showed similar efficacy in the removal of the smear layer and sealer penetration depth.

CONCLUSION: N-EDTA had negligible cytotoxicity with similar smear layer removal ability, sealer penetration, and better antibiofilm potential than MTAD.

CLINICAL RELEVANCE: N-EDTA can serve as a viable alternative endodontic irrigant.}, } @article {pmid37999531, year = {2023}, author = {Marques, A and Carabineiro, SAC and Aureliano, M and Faleiro, L}, title = {Evaluation of Gold Complexes to Address Bacterial Resistance, Quorum Sensing, Biofilm Formation, and Their Antiviral Properties against Bacteriophages.}, journal = {Toxics}, volume = {11}, number = {11}, pages = {}, doi = {10.3390/toxics11110879}, pmid = {37999531}, issn = {2305-6304}, support = {CEEC-INST/00102/2018//Fundação para a Ciência e Tecnologia/ ; FCT/MCTES (UIDB/50006/2020//Fundação para a Ciência e Tecnologia/ ; UIDP/5006/2020//Fundação para a Ciência e Tecnologia/ ; UIDB/04326/2020//Fundação para a Ciência e Tecnologia/ ; UIDP/04326/2020//Fundação para a Ciência e Tecnologia/ ; LA/P/0101/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {The worldwide increase in antibiotic resistance poses a significant challenge, and researchers are diligently seeking new drugs to combat infections and prevent bacterial pathogens from developing resistance. Gold (I and III) complexes are suitable for this purpose. In this study, we tested four gold (I and III) complexes, (1) chlorotrimethylphosphine gold(I); (2) chlorotriphenylphosphine gold(I); (3) dichloro(2-pyridinecarboxylate) gold (III); and (4) 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene gold(I) chloride, for their antibacterial, antibiofilm, antiviral, and anti-quorum sensing activities. Results reveal that 1 significantly inhibits Escherichia coli DSM 1077 and Staphylococcus aureus ATCC 6538, while 2, 3, and 4 only inhibit S. aureus ATCC 6538. The minimum inhibitory concentration (MIC) of 1 for S. aureus ATCC 6538 is 0.59 μg/mL (1.91 μM), and for methicillin-resistant S. aureus strains MRSA 12 and MRSA 15, it is 1.16 μg/mL (3.75 μM). For E. coli DSM 1077 (Gram-negative), the MIC is 4.63 μg/mL (15 μM), and for multi-resistant E. coli I731940778-1, it is 9.25 μg/mL (30 μM). Complex 1 also disrupts biofilm formation in E. coli and S. aureus after 6 h or 24 h exposure. Moreover, 1 and 2 inhibit the replication of two enterobacteria phages. Anti-quorum sensing potential still requires further clarification. These findings highlight the potential of gold complexes as effective agents to combat bacterial and viral infections.}, } @article {pmid37998947, year = {2023}, author = {Alshora, D and Ashri, L and Alfaraj, R and Alhusaini, A and Mohammad, R and Alanaze, N and Ibrahim, M and Badran, MM and Bekhit, M and Alsaif, S and Alagili, M and Ali, RA and Jreebi, A}, title = {Formulation and In Vivo Evaluation of Biofilm Loaded with Silver Sulfadiazine for Burn Healing.}, journal = {Gels (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, doi = {10.3390/gels9110855}, pmid = {37998947}, issn = {2310-2861}, support = {RSP2023R170//Research Supporting ,King Saud University, Riyadh, Saudi Arabia/ ; }, abstract = {Infected burned skin is a life-threatening condition, which may lead to sepsis. The aims of this work are to formulate a biofilm composed of silver sulfadiazine (SSD), chitosan (CS), and sodium alginate (SA), and to evaluate its wound-healing effectiveness. A full factorial design was used to formulate different matrix formulations. The prepared biofilm was tested for physicochemical, and in vitro release. The optimized formulation is composed of 0.833% of CS and 0.75% of SA. The release of SSD almost reached 100% after 6 h. The mechanical properties of the optimized formula were reasonable. The antibacterial activity for the optimized biofilm was significantly higher than that of blank biofilm, which is composed of CS and SA, p = 1.53922 × 10[-12]. Moreover, the in vivo study showed a 75% reduction in wound width when using the formulated SSD biofilm compared to standard marketed cream (57%) and the untreated group (0%).}, } @article {pmid37998883, year = {2023}, author = {Karkowska-Kuleta, J and Kulig, K and Bras, G and Stelmaszczyk, K and Surowiec, M and Kozik, A and Karnas, E and Barczyk-Woznicka, O and Zuba-Surma, E and Pyza, E and Rapala-Kozik, M}, title = {Candida albicans Biofilm-Derived Extracellular Vesicles Are Involved in the Tolerance to Caspofungin, Biofilm Detachment, and Fungal Proteolytic Activity.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, doi = {10.3390/jof9111078}, pmid = {37998883}, issn = {2309-608X}, support = {2021/43/D/NZ6/01464//National Science Center/ ; }, abstract = {It has been repeatedly reported that the cells of organisms in all kingdoms of life produce nanometer-sized lipid membrane-enveloped extracellular vesicles (EVs), transporting and protecting various substances of cellular origin. While the composition of EVs produced by human pathogenic fungi has been studied in recent decades, another important challenge is the analysis of their functionality. Thus far, fungal EVs have been shown to play significant roles in intercellular communication, biofilm production, and modulation of host immune cell responses. In this study, we verified the involvement of biofilm-derived EVs produced by two different strains of Candida albicans-C. albicans SC5314 and 3147 (ATCC 10231)-in various aspects of biofilm function by examining its thickness, stability, metabolic activity, and cell viability in the presence of EVs and the antifungal drug caspofungin. Furthermore, the proteolytic activity against the kininogen-derived antimicrobial peptide NAT26 was confirmed by HPLC analysis for C. albicans EVs that are known to carry, among others, particular members of the secreted aspartic proteinases (Saps) family. In conclusion, EVs derived from C. albicans biofilms were shown to be involved in biofilm tolerance to caspofungin, biofilm detachment, and fungal proteolytic activity.}, } @article {pmid37998832, year = {2023}, author = {Ribeiro, AB and Tinelli, BM and Clemente, LM and Poker, BC and Oliveira, VC and Watanabe, E and Silva-Lovato, CH}, title = {Effect of Hygiene Protocols on the Mechanical and Physical Properties of Two 3D-Printed Denture Resins Characterized by Extrinsic Pigmentation as Well as the Mixed Biofilm Formed on the Surface.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {11}, pages = {}, doi = {10.3390/antibiotics12111630}, pmid = {37998832}, issn = {2079-6382}, support = {2020/11054-8.//São Paulo Research Foundation/ ; }, abstract = {To assess the effect of hygiene protocols and time on the physical-mechanical properties and colony-forming units (CFU) of Candida albicans, Staphylococcus aureus, and Streptococcus mutans on 3D-printed denture resins (SmartPrint and Yller) with extrinsic pigmentation compared to conventional resin (CR). The protocols were evaluated: brushing (B), brushing and immersion in water (W), 0.25% sodium hypochlorite (SH), and 0.15% triclosan (T), simulating 0, 1, 3, and 5 years. The data were analyzed by ANOVA with repeated measurements, ANOVA (Three-way) and Tukey's post-test, generalized linear model with Bonferroni adjustment, and ANOVA (Two-way) and Tukey's post-test (α = 0.05). The protocols influenced color (p = 0.036) and Knoop hardness (p < 0.001). Surface roughness was influenced by protocols/resin (p < 0.001) and time/resin (p = 0.001), and flexural strength by time/protocols (p = 0.014). C. albicans showed interactions with all factors (p = 0.033). Staphylococcus aureus was affected by protocols (p < 0.001). Streptococcus mutans exhibited no count for SH and T (p < 0.001). Yller resin showed more color changes. The 3D-printed resins displayed lower microhardness, increased roughness, and decreased flexural strength compared to CR with all protocols in a simulated period of 5 years. The indication of printed resins should be restricted to less than 3 years.}, } @article {pmid37998803, year = {2023}, author = {Cruz, JERD and Saldanha, HC and Nascimento, AMD and Borges, RB and Gomes, MS and Freitas, GROE and Leal, CM and Ferreira, EA and da Silva Filho, AA and Morais, ER}, title = {Evaluation of the Antioxidant, Antimicrobial, and Anti-Biofilm Effects of the Stem Bark, Leaf, and Seed Extracts from Hymenaea courbaril and Characterization by UPLC-ESI-QTOF-MS/MS Analysis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {11}, pages = {}, doi = {10.3390/antibiotics12111601}, pmid = {37998803}, issn = {2079-6382}, support = {APQ-00705-22 and APQ-03773-22//Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; APC//PROPP-UFU/ ; }, abstract = {Currently, biofilm-forming bacteria are difficult to treat by conventional antibiotic therapy and are, thus, becoming a clinical and epidemiological problem worldwide. Medicinal plants have been identified as novel alternative treatments due to their therapeutic and antimicrobial effects. In this context, the present study aimed to determine the total phenolic content, antioxidant capacity, and antimicrobial and anti-biofilm potential of nine extracts of Hymenaea courbaril (Fabaceae), popularly known as Jatobá. Furthermore, extracts that exhibited biofilm inhibitory activity against S. aureus (ATCC 25923) were selected for UPLC-HRMS/MS chemical analysis. Our results showed a high total phenolic content, mainly in the stem bark extract, and that the plant is rich in compounds with antioxidant activity. In the anti-biofilm analysis, leaf extracts stood out in comparison with chloramphenicol, with inhibition percentages of 78.29% and 78.85%, respectively. Through chemical analysis by UPLC-HRMS/MS, chrysoeriol-7-O-neohesperidoside, isorhamnetin-3-O-glucoside, and 3,7-di-O-methylquercetin were annotated for the first time in the leaves of H. courbaril. Therefore, these results showed the potential use of H. courbaril as an antioxidant and point to its use in antimicrobial therapy with an anti-biofilm effect.}, } @article {pmid37998800, year = {2023}, author = {Leesombun, A and Sungpradit, S and Sariya, L and Taowan, J and Boonmasawai, S}, title = {Transcriptional Profiling of the Effect of Coleus amboinicus L. Essential Oil against Salmonella Typhimurium Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {11}, pages = {}, doi = {10.3390/antibiotics12111598}, pmid = {37998800}, issn = {2079-6382}, support = {Specific League Funds//Mahidol University/ ; }, abstract = {Salmonella enterica serovar Typhimurium cause infections primarily through foodborne transmission and remains a significant public health concern. The biofilm formation of this bacteria also contributes to their multidrug-resistant nature. Essential oils from medicinal plants are considered potential alternatives to conventional antibiotics. Therefore, this study assessed the antimicrobial and antibiofilm activities of Coleus amboinicus essential oil (EO-CA) against S. Typhimurium ATCC 14028. Seventeen chemical compounds of EO-CA were identified, and carvacrol (38.26%) was found to be the main constituent. The minimum inhibitory concentration (MIC) of EO-CA for S. Typhimurium planktonic growth was 1024 µg/mL while the minimum bactericidal concentration was 1024 µg/mL. EO-CA at sub-MIC (≥1/16× MIC) exhibited antibiofilm activity against the prebiofilm formation of S. Typhimurium at 24 h. Furthermore, EO-CA (≥1/4× MIC) inhibited postbiofilm formation at 24 and 48 h (p < 0.05). Transcriptional profiling revealed that the EO-CA-treated group at 1/2× MIC had 375 differentially expressed genes (DEGs), 106 of which were upregulated and 269 were downregulated. Five significantly downregulated virulent DEGs responsible for motility (flhD, fljB, and fimD), curli fimbriae (csgD), and invasion (hilA) were screened via quantitative reverse transcription PCR (qRT-PCR). This study suggests the potential of EO-CA as an effective antimicrobial agent for combating planktonic and biofilm formation of Salmonella.}, } @article {pmid37998031, year = {2023}, author = {Plotkin, BJ and Halkyard, S and Spoolstra, E and Micklo, A and Kaminski, A and Sigar, IM and Konaklieva, MI}, title = {The Role of the Insulin/Glucose Ratio in the Regulation of Pathogen Biofilm Formation.}, journal = {Biology}, volume = {12}, number = {11}, pages = {}, doi = {10.3390/biology12111432}, pmid = {37998031}, issn = {2079-7737}, support = {N/A//Midwestern University/ ; }, abstract = {UNLABELLED: During the management of patients in acute trauma the resulting transient hyperglycemia is treated by administration of insulin. Since the effect of insulin, a quorum sensing compound, together with glucose affects biofilm formation in a concentration-specific manner, we hypothesize that the insulin/glucose ratio over the physiologic range modulates biofilm formation potentially influencing the establishment of infection through biofilm formation.

METHODS: A variety of Gram-positive and Gram-negative bacteria were grown in peptone (1%) yeast nitrogen base broth overnight in 96-well plates with various concentrations of glucose and insulin. Biofilm formation was determined by the crystal violet staining procedure. Expression of insulin binding was determined by fluorescent microscopy (FITC-insulin). Controls were buffer alone, insulin alone, and glucose alone.

RESULTS: Overall, maximal biofilm levels were measured at 220 mg/dL of glucose, regardless of insulin concentration (10, 100, 200 µU/mL) of the organism tested. In general, insulin with glucose over the range of 160-180 mg/dL exhibited a pattern of biofilm suppression. However, either above or below this range, the presence of insulin in combination with glucose significantly modulated (increase or decrease) biofilm formation in a microbe-specific pattern. This modulation appears for some organisms to be reflective of the glucose-regulated intrinsic expression of bacterial insulin receptor expression.

CONCLUSION: Insulin at physiologic levels (normal and hyperinsulinemic) in combination with glucose can affect biofilm formation in a concentration-specific and microbe-specific manner. These findings may provide insight into the importance of co-regulation of the insulin/glucose ratio in patient management.}, } @article {pmid37996471, year = {2023}, author = {Yang, L and Zhang, D and Li, W and Lin, H and Ding, C and Liu, Q and Wang, L and Li, Z and Mei, L and Chen, H and Zhao, Y and Zeng, X}, title = {Biofilm microenvironment triggered self-enhancing photodynamic immunomodulatory microneedle for diabetic wound therapy.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {7658}, pmid = {37996471}, issn = {2041-1723}, abstract = {The treatment of diabetic wounds faces enormous challenges due to complex wound environments, such as infected biofilms, excessive inflammation, and impaired angiogenesis. The critical role of the microenvironment in the chronic diabetic wounds has not been addressed for therapeutic development. Herein, we develop a microneedle (MN) bandage functionalized with dopamine-coated hybrid nanoparticles containing selenium and chlorin e6 (SeC@PA), which is capable of the dual-directional regulation of reactive species (RS) generation, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), in response to the wound microenvironment. The SeC@PA MN bandage can disrupt barriers in wound coverings for efficient SeC@PA delivery. SeC@PA not only depletes endogenous glutathione (GSH) to enhance the anti-biofilm effect of RS, but also degrades GSH in biofilms through cascade reactions to generate more lethal RS for biofilm eradication. SeC@PA acts as an RS scavenger in wound beds with low GSH levels, exerting an anti-inflammatory effect. SeC@PA also promotes the M2-phenotype polarization of macrophages, accelerating wound healing. This self-enhanced, catabolic and dynamic therapy, activated by the wound microenvironment, provides an approach for treating chronic wounds.}, } @article {pmid37995876, year = {2023}, author = {Chang, JY and Syauqi, TA and Sudesh, K and Ng, SL}, title = {Insights into biofilm development on polyhydroxyalkanoate biofilm carrier for anoxic azo dye decolourization of acid orange 7.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130054}, doi = {10.1016/j.biortech.2023.130054}, pmid = {37995876}, issn = {1873-2976}, abstract = {Polyhydroxyalkanoates (PHAs) are promising alternatives to non-degradable polymers in various applications. This study explored the use of biologically recovered PHA as a biofilm carrier in a moving bed biofilm reactor for acid orange 7 treatment. The PHA was comprised of 86 ± 1 mol% of 3-hydroxybutyrate and 14 ± 1 mol% of 3-hydroxyhexanoate and was melt-fused at 140 °C into pellets. The net positive surface charge of the PHA biocarrier facilitated attachment of negatively charged activated sludge, promoting biofilm formation. A 236-µm mature biofilm developed after 26 days. The high polysaccharides-to-protein ratio (>1) in the biofilm's extracellular polymeric substances indicated a stable biofilm structure. Four main microbial strains in the biofilm were identified as Leclercia adecarboxylata, Leuconostoc citreum, Bacillus cereus, and Rhodotorula mucilaginosa, all of which exhibited decolourization abilities. In conclusion, PHA holds promise as an effective biocarrier for biofilm development, offering a sustainable alternative in wastewater treatment applications.}, } @article {pmid37995875, year = {2023}, author = {Wang, Y and Zhang, X and Wu, Y and Sun, G and Jiang, Z and Hao, S and Ye, S and Zhang, H and Zhang, F and Zhang, X}, title = {Improving biomass yields of microalgae biofilm by coculturing two microalgae species via forming biofilms with uniform microstructures and small cell-clusters.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130052}, doi = {10.1016/j.biortech.2023.130052}, pmid = {37995875}, issn = {1873-2976}, abstract = {Microalgae coculture has the potential to promote microalgae biofilm growth. Herein, three two-species cocultured biofilms were studied by determining biomass yields and detailed microstructure parameters, including porosity, average pore length, average cluster length, etc. It was found that biomass yields could reduce by 21-53 % when biofilm porosities decreased from about 35 % to 20 %; while at similar porosities (∼20 %), biomass yields of cocultured biofilms increased by 37 % when they possessed uniform microstructure and small cell-clusters (pores and clusters of 1 ∼ 10 μm accounted for 96 % and 68 %, respectively). By analyzing morphologies and surface properties of cells, it was found that cells with small size, spherical shape, and reduced surface polymers could hinder the cell-clusters formation, thereby promoting biomass yields. The study would provide new insights into choosing cocultured microalgae species for improving the biomass yield of biofilm via manipulating biofilm microstructures.}, } @article {pmid37995872, year = {2023}, author = {Li, J and Zhang, F and Ma, B and Kong, D and Hu, Y and Chen, G and Ruan, Y}, title = {Characterization of simultaneous ammonium and nitrate removal and microbial communities in airlift reactor using 3-hydroxybutyrate-co-3-hydroxyvalerate as carbon source and biofilm carrier.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130049}, doi = {10.1016/j.biortech.2023.130049}, pmid = {37995872}, issn = {1873-2976}, abstract = {As a novel trend, solid carbon sources are applied to act as electron donors and biofilm carrier in biological denitrification process. In this study, simultaneous nitrate and ammonium removal process in an airlift sequencing batch reactor using 3-hydroxybutyrate-co-3-hydroxyvalerate as carbon source and biofilm carrier under intermittent aeration conditions was established to treat effluent of synthetic marine recirculating aquaculture system. The results showed that maximum nitrate and ammonia nitrogen removal rates of 0.45 and 0.09 kg m[-3] d[-1] were achieved. No significant nitrite accumulation was found during 200-day operation, while effluent dissolved organic carbon accumulation and particle size reduction significantly increased. Microbial community analysis and batch tests illuminate that the generated sludge and attached biofilm played important roles in nitrogen removal. This study demonstrates the potential mechanism for the nitrogen removal process mediated by 3-hydroxybutyrate-co-3-hydroxyvalerate and provide a new idea for the alternative solutions of solid carbon sources.}, } @article {pmid37994324, year = {2023}, author = {Upadhyay, A and Pal, D and Kumar, A}, title = {Deciphering Target Protein Cascade in Salmonella typhi Biofilm using Genomic Data Mining, and Protein-protein Interaction.}, journal = {Current genomics}, volume = {24}, number = {2}, pages = {100-109}, pmid = {37994324}, issn = {1389-2029}, abstract = {BACKGROUND: Salmonella typhi biofilm confers a serious public health issue for lengthy periods and the rise in antibiotic resistance and death rate. Biofilm generation has rendered even the most potent antibiotics ineffective in controlling the illness, and the S. typhi outbreak has turned into a fatal disease typhoid. S. typhi infection has also been connected to other deadly illnesses, such as a gall bladder cancer. The virulence of this disease is due to the interaction of numerous genes and proteins of S. typhi.

OBJECTIVE: The study aimed to identify a cascade of target proteins in S. typhi biofilm condition with the help of genomic data mining and protein-protein interaction analysis.

METHODS: The goal of this study was to notice some important pharmacological targets in S. typhi. using genomic data mining, and protein-protein interaction approaches were used so that new drugs could be developed to combat the disease.

RESULTS: In this study, we identified 15 potential target proteins that are critical for S. typhi biofilm growth and maturation. Three proteins, CsgD, AdrA, and BcsA, were deciphered with their significant role in the synthesis of cellulose, a critical component of biofilm's extracellular matrix. The CsgD protein was also shown to have high interconnectedness and strong interactions with other important target proteins of S. typhi. As a result, it has been concluded that CsgD is involved in a range of activities, including cellulose synthesis, bacterial pathogenicity, quorum sensing, and bacterial virulence.

CONCLUSION: All identified targets in this study possess hydrophobic properties, and their cellular localization offered proof of a potent therapeutic target. Overall results of this study, drug target shortage in S. typhi is also spotlighted, and we believe that obtained result could be useful for the design and development of some potent anti-salmonella agents for typhoid fever in the future.}, } @article {pmid37993891, year = {2023}, author = {Wang, Z and Chen, R and Xia, F and Jiang, M and Zhu, D and Zhang, Y and Dai, J and Zhuge, X}, title = {ProQ binding to small RNA RyfA promotes virulence and biofilm formation in avian pathogenic Escherichia coli.}, journal = {Veterinary research}, volume = {54}, number = {1}, pages = {109}, pmid = {37993891}, issn = {1297-9716}, support = {BE2022329//Jiangsu Provincial Key Research and Development Program/ ; 32172855//National Natural Science Foundation of China/ ; 31702252//National Natural Science Foundation of China/ ; CX(21)3126//Jiangsu Agricultural Science and Technology Innovation Fund/ ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is a notable subpathotype of the nonhuman extraintestinal pathogenic E. coli (ExPEC). Recognized as an extraintestinal foodborne pathogen, the zoonotic potential of APEC/ExPEC allows for cross-host transmission via APEC-contaminated poultry meat and eggs. ProQ, an RNA binding protein, is evolutionarily conserved in E. coli. However, its regulatory roles in the biofilm formation and virulence of APEC/ExPEC have not been explored. In this study, proQ deletion in the APEC strain FY26 significantly compromised its biofilm-forming ability. Furthermore, animal tests and cellular infection experiments showed that ProQ depletion significantly attenuated APEC virulence, thereby diminishing its capacity for bloodstream infection and effective adherence to and persistence within host cells. Transcriptome analysis revealed a decrease in the transcription level of the small RNA (sRNA) RyfA in the mutant FY26ΔproQ, suggesting a direct interaction between the sRNA RyfA and ProQ. This interaction might indicate that sRNA RyfA is a novel ProQ-associated sRNA. Moreover, the direct binding of ProQ to the sRNA RyfA was crucial for APEC biofilm formation, pathogenicity, adhesion, and intracellular survival. In conclusion, our findings provide detailed insight into the interaction between ProQ and sRNA RyfA and deepen our understanding of the regulatory elements that dictate APEC virulence and biofilm development. Such insights are instrumental in developing strategies to counteract APEC colonization within hosts and impede APEC biofilm establishment on food surfaces.}, } @article {pmid37993249, year = {2023}, author = {Hof, C and Khan, MF and Murphy, CD}, title = {Endogenous production of 2-phenylethanol by Cunninghamella echinulata inhibits biofilm growth of the fungus.}, journal = {Fungal biology}, volume = {127}, number = {10-11}, pages = {1384-1388}, doi = {10.1016/j.funbio.2023.10.001}, pmid = {37993249}, issn = {1878-6146}, abstract = {The filamentous fungus Cunninghamella echinulata is a model of mammalian xenobiotic metabolism. Under certain conditions it grows as a biofilm, which is a natural form of immobilisation and enables the fungus to catalyse repeated biotransformations. Putative signalling molecules produced by other Cunninghamella spp., such as 3-hydroxytyrosol and tyrosol, do not affect the biofilm growth of C. echinulata, suggesting that it employs a different molecule to regulate biofilm growth. In this paper we report that 2-phenylethanol is produced in higher concentrations in planktonic cultures of C. echinulata than when the fungus is grown as a biofilm. We demonstrate that exogenously added 2-phenylethanol inhibits biofilm growth of C. echinulata but has no effect on planktonic growth. Furthermore, we show that addition of 2-phenylethanol to established C. echinulata biofilm causes detachment. Therefore, we conclude that this molecule is produced by the fungus to regulate biofilm growth.}, } @article {pmid37992925, year = {2023}, author = {Yan, H and Wen, P and Tian, S and Zhang, H and Han, B and Khan, J and Xue, Y and Chen, X and Li, X and Li, Y}, title = {Enhancing biofilm penetration and antibiofilm efficacy with protein nanocarriers against pathogenic biofilms.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128300}, doi = {10.1016/j.ijbiomac.2023.128300}, pmid = {37992925}, issn = {1879-0003}, abstract = {Nanocarriers play an important role in enhancing the efficacy of antibiotics against biofilms by improving their penetration and prolonging retention in pathogenic biofilms. Herein, the multifunctional nanocarriers including nanospheres (NS) and nanotubes (NT) with a high biocompatibility and biodegradability were prepared through self-assembly of partially hydrolyzed α-lactalbumin. The effects of these two different shaped nanocarriers on the delivery of antibiotics for biofilm treatment were examined by conducting in vitro antibiofilm experiment and in vivo infected wound model. The strong affinity of NS and NT for the bacterial surface allows antibiotics to be concentrated in the bacteria. Notably, the high permeability of NT into biofilms facilitates deeper penetration and the easier diffusion of loaded antibiotics within the biofilm. Furthermore, the acidic biofilm environment triggers the release of antibiotics from the NT, resulting in the accumulation of high local antibiotic concentrations. Therefore, NT could efficiently clean and inhibit the biofilm formation while also destroying the mature biofilms. In a S. aureus infected wound animal model, treatment with antibiotic-loaded NT demonstrated accelerated healing of S. aureus infected wounds when compared to free antibiotic treatment. These findings indicate that NT nanocarrier strategy is promising for treating bacterial biofilm infections, offering the potential for lower antibiotics dosages and preventing the overuse of antibiotics.}, } @article {pmid37992874, year = {2023}, author = {Li, P and Pan, J and Dong, Y and Sun, Y and Wang, Y and Liao, K and Chen, Y and Deng, X and Yu, S and Hu, H}, title = {Microenvironment responsive charge-switchable nanoparticles act on biofilm eradication and virulence inhibition for chronic lung infection treatment.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jconrel.2023.11.032}, pmid = {37992874}, issn = {1873-4995}, abstract = {Chronic pulmonary infection caused by Pseudomonas aeruginosa (P. aeruginosa) is a common lung disease with high mortality, posing severe threats to public health. Highly resistant biofilm and intrinsic resistance make P. aeruginosa hard to eradicate, while powerful virulence system of P. aeruginosa may give rise to the recurrence of infection and eventual failure of antibiotic therapy. To address these issues, infection-microenvironment responsive nanoparticles functioning on biofilm eradication and virulence inhibition were simply prepared by electrostatic complexation between dimethylmaleic anhydride (DA) modified negatively charged coating and epsilon-poly(l-lysine) derived cationic nanoparticles loaded with azithromycin (AZI) (DA-AZI NPs). Charge reversal responsive to acidic condition enabled DA-AZI NPs to successively penetrate through both mucus and biofilms, followed by targeting to P. aeruginosa and permeabilizing its outer/inner membrane. Then in situ released AZI, which was induced by the lipase-triggered NPs dissociation, could easily enter into bacteria to take effects. DA-AZI NPs exhibited enhanced eradication activity against P. aeruginosa biofilms with a decrease of >99.999% of bacterial colonies, as well as remarkable inhibitory effects on the production of virulence factors and bacteria re-adhesion & biofilm re-formation. In a chronic pulmonary infection model, nebulization of DA-AZI NPs into infected mice resulted in prolonged retention and increased accumulation of the NPs in the infected sites of the lungs. Moreover, they significantly reduced the burden of P. aeruginosa, effectively alleviating lung tissue damages and inflammation. Overall, the proposed DA-AZI NPs highlight an innovative strategy for treating chronic pulmonary infection.}, } @article {pmid37992655, year = {2023}, author = {Zhong, H and Jiang, C and He, X and He, J and Zhao, Y and Chen, Y and Huang, L}, title = {Simultaneous change of microworld and biofilm formation in constructed wetlands filled with biochar.}, journal = {Journal of environmental management}, volume = {349}, number = {}, pages = {119583}, doi = {10.1016/j.jenvman.2023.119583}, pmid = {37992655}, issn = {1095-8630}, abstract = {As the regulator of constructed wetlands (CWs), biochar is often used to enhance pollutant removal and reduce greenhouse gas emission. Biochar is proved to have certain effects on microbial populations, but its effect on the aggregation of microbial flocs and the formation of biofilms in the CWs has not been thoroughly investigated. Therefore, the above topics were studied in this paper by adding a certain proportion of biochar in aerated subsurface flow constructed wetlands. The results indicated that after adding biochar in the CWs, pollutant removal was enhanced and the removal rate of NH4[+]-N was increased from 80.76% to 99.43%. The proportion of hydrophobic components in extracellular polymeric substances (EPS) was reduced by adding biochar from 0.0044 to 0.0038, and the affinity of EPS on CH3-SAM was reduced from 5.736 L/g to 2.496 L/g. The weakened hydrophobic and the reduced affinity of EPS caused the initial attachment of microorganisms to be inhibited. The relative abundance of Chloroflexi was decreased after adding biochar, reducing the dense structural skeleton of biofilm aggregates. Correspondingly, the abundance of Bacteroidetes was increased, promoting EPS degradation. Biochar addition helped to increase the proportion of catalytic active proteins in extracellular proteins and decrease the proportion of binding active proteins, hindering the combination of extracellular proteins and macromolecules to form microbial aggregates. Additionally, the proportions of three extracellular protein structures promoting microbial aggregation, including aggregated chain, β-sheet, and 3-turn helix, were decreased to 23.83%, 38.37% and 7.76%, respectively, while the proportions of random coil and antiparallel β-sheet that inhibited microbial aggregation were increased to 14.11% and 8.11%, respectively. An interesting conclusion from the experimental results is that biochar not only can enhance pollutants removal, but also has the potential of alleviating biological clogging in CWs, which is of great significance to realize the sustainable operation and improve the life cycle of CWs.}, } @article {pmid37992081, year = {2023}, author = {Basnet, A and Tamang, B and Shrestha, MR and Shrestha, LB and Rai, JR and Maharjan, R and Dahal, S and Shrestha, P and Rai, SK}, title = {Assessment of four in vitro phenotypic biofilm detection methods in relation to antimicrobial resistance in aerobic clinical bacterial isolates.}, journal = {PloS one}, volume = {18}, number = {11}, pages = {e0294646}, doi = {10.1371/journal.pone.0294646}, pmid = {37992081}, issn = {1932-6203}, abstract = {INTRODUCTION: The lack of standardized methods for detecting biofilms continues to pose a challenge to microbiological diagnostics since biofilm-mediated infections induce persistent and recurrent infections in humans that often defy treatment with common antibiotics. This study aimed to evaluate diagnostic parameters of four in vitro phenotypic biofilm detection assays in relation to antimicrobial resistance in aerobic clinical bacterial isolates.

METHODS: In this cross-sectional study, bacterial strains from clinical samples were isolated and identified following the standard microbiological guidelines. The antibiotic resistance profile was assessed through the Kirby-Bauer disc diffusion method. Biofilm formation was detected by gold standard tissue culture plate method (TCPM), tube method (TM), Congo red agar (CRA), and modified Congo red agar (MCRA). Statistical analyses were performed using SPSS version 17.0, with a significant association considered at p<0.05.

RESULT: Among the total isolates (n = 226), TCPM detected 140 (61.95%) biofilm producers, with CoNS (9/9) (p<0.001) as the predominant biofilm former. When compared to TCPM, TM (n = 119) (p<0.001) showed 90.8% sensitivity and 70.1% specificity, CRA (n = 88) (p = 0.123) showed 68.2% sensitivity and 42% specificity, and MCRA (n = 86) (p = 0.442) showed 65.1% sensitivity and 40% specificity. Juxtaposed to CRA, colonies formed on MCRA developed more intense black pigmentation from 24 to 96 hours. There were 77 multi-drug-resistant (MDR)-biofilm formers and 39 extensively drug-resistant (XDR)-biofilm formers, with 100% resistance to ampicillin and ceftazidime, respectively.

CONCLUSION: It is suggested that TM be used for biofilm detection, after TCPM. Unlike MCRA, black pigmentation in colonies formed on CRA declined with time. MDR- and XDR-biofilm formers were frequent among the clinical isolates.}, } @article {pmid37991569, year = {2023}, author = {He, J and Qi, P and Zhang, D and Zeng, Y and Zhao, P and Wang, P}, title = {Determination of sulfide in complex biofilm matrices using silver-coated, 4-mercaptobenzonitrile-modified gold nanoparticles, encapsulated in ZIF-8 as surface-enhanced Raman scattering nanoprobe.}, journal = {Mikrochimica acta}, volume = {190}, number = {12}, pages = {475}, pmid = {37991569}, issn = {1436-5073}, support = {42376208//National Natural Science Foundation of China/ ; XDA23050104//Strategic Priority Research Program of Chinese Academy of Sciences/ ; }, abstract = {A surface-enhanced Raman scattering nanoprobe has been developed for sulfide detection and applied to complex bacterial biofilms. The nanoprobe, Au@4-MBN@Ag@ZIF-8, comprised a gold core modified with 4-mercaptobenzonitrile (4-MBN) as signaling source, a layer of silver shell as the sulfide sensitization material, and a zeolitic imidazolate framework-8 (ZIF-8) as surface barrier. ZIF-8, with its high surface area and mesoporous structure, was applied to preconcentrate sulfide around the nanoprobe with its excellent adsorption capacity. Besides, the external wrapping of ZIF-8 can not only prevent the interference of biomolecules, such as proteins, with the Au@4-MBN@Ag assay but also enhance the detection specificity through the sulfide cleavage function towards ZIF-8. These properties are critical for the application of this nanoprobe to complex environmental scenarios. In the presence of sulfide, it was first enriched through adsorption by the outer ZIF-8 layer, then destroyed the barrier layer, and subsequently reacted with the Ag shell, leading to changes in the Raman signal. Through this rational design, the Au@4-MBN@Ag@ZIF-8 nanoprobe exhibited excellent detection sensitivity, with a sulfide detection limit in the nanomolar range and strong linearity in the concentration range 50 nM to 500 μM. Furthermore, the proposed Au@4-MBN@Ag@ZIF-8 nanoprobe was effectively utilized for sulfide detection in intricate biofilm matrices, demonstrating its robust selectivity and reproducibility.}, } @article {pmid37989417, year = {2023}, author = {Liu, Y and Tang, S and Yan, Q and Zhou, J and Cai, Z}, title = {Effectiveness and associated mechanisms of a combination of biofilm attached cultivation and mixotrophy in promoting microalgal biomass.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130077}, doi = {10.1016/j.biortech.2023.130077}, pmid = {37989417}, issn = {1873-2976}, abstract = {The effectiveness and associated mechanisms of the biofilm attached cultivation (BAC) under mixotrophy in promoting algal proliferation were investigated. Commercially valuable unicellular microalga Chromochloris zofingiensis was first used in BAC. Compared with suspended cultivation, the results unequivocally demonstrated the growth benefits of C. zofingiensis cells under BAC with high biomass productivity of 8.53 g m[-2] d[-1]. The physiological and transcriptomic data revealed that the augmented biomass yield was attributable to larger cell size, higher accumulation of chemical substances, significantly upregulated carbon fixation pathway, and greater energy supply efficiency. Here, BAC acts as a "cage" was proposed. Specifically, cells allocate less energy toward mobility, directing a higher share toward growth and production due to their immobilized lifestyle. These findings provide novel insights for optimizing cultivation strategies for commercially valuable algal species and offer a novel perspective from microalgae physiological on understanding higher biomass yield in BAC.}, } @article {pmid37988240, year = {2023}, author = {Xiao, WN and Nunn, GM and Fufeng, AB and Belu, N and Brookman, RK and Halim, A and Krysmanski, EC and Cameron, RK}, title = {Exploring Pseudomonas syringae pv. tomato biofilm-like aggregate formation in susceptible and PTI-responding Arabidopsis thaliana.}, journal = {Molecular plant pathology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mpp.13403}, pmid = {37988240}, issn = {1364-3703}, support = {//Natural Science and Engineering Council (NSERC)/ ; }, abstract = {Bacterial biofilm-like aggregates have been observed in plants, but their role in pathogenicity is underinvestigated. In the present study, we observed that extracellular DNA and polysaccharides colocalized with green fluorescent protein (GFP)-expressing Pseudomonas syringae pv. tomato (Pst) aggregates in Arabidopsis leaves, suggesting that Pst aggregates are biofilms. GFP-expressing Pst, Pst ΔalgU ΔmucAB (Pst algU mutant), and Pst ΔalgD ΔalgU ΔmucAB (Pst algU algD mutant) were examined to explore the roles of (1) alginate, a potential biofilm component; (2) Pst AlgU, thought to regulate alginate biosynthesis and some type III secretion system effector genes; and (3) intercellular salicylic acid (SA) accumulation during pathogen-associated molecular pattern-triggered immunity (PTI). Pst formed extensive aggregates in susceptible plants, whereas aggregate numbers and size were reduced in Pst algU and Pst algD algU mutants, and both multiplied poorly in planta, suggesting that aggregate formation contributes to Pst success in planta. However, in SA-deficient sid2-2 plants, Pst algD algU mutant multiplication and aggregate formation were partially restored, suggesting plant-produced SA contributes to suppression of Pst aggregate formation. Pst algD algU mutants formed fewer and smaller aggregates than Pst algU mutants, suggesting both AlgU and AlgD contribute to Pst aggregate formation. Col-0 plants accumulated low levels of SA in response to Pst and both mutants (Pst algU and Pst algD algU), suggesting the regulatory functions of AlgU are not involved in suppressing SA-mediated plant defence. Plant PTI was associated with highly reduced Pst aggregate formation and accumulation of intercellular SA in flg22-induced PTI-responding wild-type Col-0, but not in PTI-incompetent fls2, suggesting intercellular SA accumulation by Arabidopsis contributes to suppression of Pst biofilm-like aggregate formation during PTI.}, } @article {pmid37987271, year = {2023}, author = {Hernández-Cuellar, E and Tsuchiya, K and Valle-Ríos, R and Medina-Contreras, O}, title = {Differences in Biofilm Formation by Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Strains.}, journal = {Diseases (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, doi = {10.3390/diseases11040160}, pmid = {37987271}, issn = {2079-9721}, support = {After acceptance//Autonomous University of Aguascalientes/ ; }, abstract = {Staphylococcus aureus (S. aureus) is a common pathogen involved in community- and hospital-acquired infections. Its biofilm formation ability predisposes it to device-related infections. Methicillin-resistant S. aureus (MRSA) strains are associated with more serious infections and higher mortality rates and are more complex in terms of antibiotic resistance. It is still controversial whether MRSA are indeed more virulent than methicillin-susceptible S. aureus (MSSA) strains. A difference in biofilm formation by both types of bacteria has been suggested, but how only the presence of the SCCmec cassette or mecA influences this phenotype remains unclear. In this review, we have searched for literature studying the difference in biofilm formation by MRSA and MSSA. We highlighted the relevance of the icaADBC operon in the PIA-dependent biofilms generated by MSSA under osmotic stress conditions, and the role of extracellular DNA and surface proteins in the PIA-independent biofilms generated by MRSA. We described the prominent role of surface proteins with the LPXTG motif and hydrolases for the release of extracellular DNA in the MRSA biofilm formation. Finally, we explained the main regulatory systems in S. aureus involved in virulence and biofilm formation, such as the SarA and Agr systems. As most of the studies were in vitro using inert surfaces, it will be necessary in the future to focus on biofilm formation on extracellular matrix components and its relevance in the pathogenesis of infection by both types of strains using in vivo animal models.}, } @article {pmid37985771, year = {2023}, author = {Dergham, Y and Le Coq, D and Nicolas, P and Bidnenko, E and Dérozier, S and Deforet, M and Huillet, E and Sanchez-Vizuete, P and Deschamps, J and Hamze, K and Briandet, R}, title = {Direct comparison of spatial transcriptional heterogeneity across diverse Bacillus subtilis biofilm communities.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {7546}, pmid = {37985771}, issn = {2041-1723}, abstract = {Bacillus subtilis can form various types of spatially organised communities on surfaces, such as colonies, pellicles and submerged biofilms. These communities share similarities and differences, and phenotypic heterogeneity has been reported for each type of community. Here, we studied spatial transcriptional heterogeneity across the three types of surface-associated communities. Using RNA-seq analysis of different regions or populations for each community type, we identified genes that are specifically expressed within each selected population. We constructed fluorescent transcriptional fusions for 17 of these genes, and observed their expression in submerged biofilms using time-lapse confocal laser scanning microscopy (CLSM). We found mosaic expression patterns for some genes; in particular, we observed spatially segregated cells displaying opposite regulation of carbon metabolism genes (gapA and gapB), indicative of distinct glycolytic or gluconeogenic regimes coexisting in the same biofilm region. Overall, our study provides a direct comparison of spatial transcriptional heterogeneity, at different scales, for the three main models of B. subtilis surface-associated communities.}, } @article {pmid37985524, year = {2023}, author = {El-Telbany, M and Lin, CY and Abdelaziz, MN and Maung, AT and El-Shibiny, A and Mohammadi, TN and Zayda, M and Wang, C and Zar Chi Lwin, S and Zhao, J and Masuda, Y and Honjoh, KI and Miyamoto, T and El, M}, title = {Potential application of phage vB_EfKS5 to control Enterococcus faecalis and its biofilm in food.}, journal = {AMB Express}, volume = {13}, number = {1}, pages = {130}, pmid = {37985524}, issn = {2191-0855}, abstract = {Contaminated food with antibiotic-resistant Enterococcus spp. could be the vehicle for transmitting Enterococcus to humans and accordingly cause a public health problem. The accumulation of biogenic amines produced by Enterococcus faecalis (E. faecalis) in food may have cytological effects. Bacteriophages (phage in short) are natural antimicrobial agents and can be used alone or in combination with other food preservatives to reduce food microbial contaminants. The aim of this study was to isolate a novel phage against E. faecalis and determine its host range to evaluate its potential application. Bacteriophage, vB_EfKS5, with a broad host range, was isolated to control the growth of E. faecalis. The vB_EfKS5 genome is 59,246 bp in length and has a GC content of 39.7%. The computational analysis of phage vB_EfKS5 genome confirmed that it does not contain any lysogenic, toxic, or virulent genes. Phage vB_EfKS5 exhibited lytic activity against most E. faecalis isolates with different multiplicities of infections and it infected 75.5% (22/29) of E. faecalis isolates and 42.3% (3/7) of E. faecium isolates. It was also able to destroy the biofilm formed by E. faecalis with different MOIs. Phage vB_EfKS5 alone or in combination with nisin could control the growth of E. faecalis in broth and milk. Based on its high productivity, stability, short latent period, and large burst size, phage vB_EfKS5 has a high potential for applications both in food and medical applications.}, } @article {pmid37985120, year = {2024}, author = {Malani, M and Thodikayil, AT and Saha, S and Nirmal, J}, title = {Carboxylated nanofibrillated cellulose empowers moxifloxacin to overcome Staphylococcus aureus biofilm in bacterial keratitis.}, journal = {Carbohydrate polymers}, volume = {324}, number = {}, pages = {121558}, doi = {10.1016/j.carbpol.2023.121558}, pmid = {37985120}, issn = {1879-1344}, abstract = {Bacterial keratitis is one of the vision-threatening ocular diseases that is increasing at an alarming rate due to antimicrobial resistance. One of the primary causes of antimicrobial resistance could be biofilm formation, which alters the mechanism and physiology of the microorganisms. Even a potent drug fails to inhibit biofilm due to the extracellular polysaccharide matrix surrounding the bacteria, inhibiting the permeation of drugs. Therefore, we aimed to develop carboxylated nanocellulose fibers loaded with moxifloxacin (Mox-cNFC) as a novel drug delivery system to treat bacterial corneal infection. Nanocellulose fibers were fabricated using a two-step method involving citric acid hydrolysis followed by TEMPO oxidation to introduce carboxylated groups (1.12 mmol/g). The Mox-cNFC particles showed controlled drug release till 40 h through diffusion. In vitro biofilm inhibition studies showed the particle's ability to disrupt the biofilm matrix and enhance the drug penetration to achieve optimal concentrations that inhibit the persister cells (without increasing minimum inhibitory concentration), thereby reducing the bacterial drug-resistant property. In vivo studies revealed the therapeutic potential of Mox-cNFC to treat Staphylococcus aureus-induced bacterial keratitis with once-a-day treatment, unlike neat moxifloxacin. Mox-cNFC could improve patient compliance by reducing the frequency of instillation and a controlled drug release to prevent toxicity.}, } @article {pmid37985096, year = {2024}, author = {He, R and Wei, P and Odiba, AS and Gao, L and Usman, S and Gong, X and Wang, B and Wang, L and Jin, C and Lu, G and Fang, W}, title = {Amino sugars influence Aspergillus fumigatus cell wall polysaccharide biosynthesis, and biofilm formation through interfering galactosaminogalactan deacetylation.}, journal = {Carbohydrate polymers}, volume = {324}, number = {}, pages = {121511}, doi = {10.1016/j.carbpol.2023.121511}, pmid = {37985096}, issn = {1879-1344}, abstract = {Aspergillus fumigatus is a ubiquitous fungal pathogen responsible for a significant number of deaths annually due to invasive aspergillosis infection. While the utilization of diverse carbon sources, including amino sugars, has been explored in other fungi, its impact on A. fumigatus remains uncharted territory. In this study, we investigated A. fumigatus responses to glucose (Glc), glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) as carbon sources. GlcN inhibited growth, reduced sporulation and delayed germination, while GlcNAc had no such effects. Both amino sugars induced alterations in cell wall composition, leading to a reduction in glucan and galactomannan levels while increasing chitin and mannan content, rendering A. fumigatus susceptible to cell wall stress and osmotic stress. GlcN repressed biofilm formation via downregulation of galactosaminogalactan (GAG) cluster genes, notably agd3, which encodes a GAG-specific deacetylase. Moreover, GlcN increased biofilm susceptibility to echinocandins, suggesting its potential for enhancing the effectiveness of antifungal treatments. This study sheds light on the multifaceted effects of amino sugars on A. fumigatus, encompassing growth, cell wall biosynthesis, and biofilm formation, offering promising avenues for innovative aspergillosis treatment strategies.}, } @article {pmid37984669, year = {2023}, author = {Yu, M and Wang, L and Feng, P and Wang, Z and Zhu, S}, title = {Treatment of mixed wastewater by vertical rotating microalgae-bacteria symbiotic biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {130057}, doi = {10.1016/j.biortech.2023.130057}, pmid = {37984669}, issn = {1873-2976}, abstract = {A novel vertical rotating microalgae-bacteria symbiotic biofilm reactor was built to treat the mixed wastewater containing municipal and soybean soaking wastewater. The reactor was operated in both sequential batch and semi-continuous modes. Under the sequential batch operation mode, the maximum removal rates for Chemical Oxygen Demand (COD), Total Nitrogen (TN), Total Phosphorus (TP), and Ammonia Nitrogen (NH4[+]-N) of the mixed wastewater were 95.6 %, 96.1 %, 97.6 %, and 100 %, respectively. During the semi-continuous operation, the water discharge indices decreased gradually and eventually stabilized. At stabilization, the removal rates of COD, TN, and NH4[+]-N achieved 98 %, 95 %, and 99.9 %, respectively. The maximum biomass productivity of the biofilm was 2.69 g·m[-2]·d[-1]. Additionally, the carbohydrate, protein and lipid comprised approximately 22 %, 51 % and 10 % of the dry weight of Chlorella. This study demonstrates the great potential of the microalgae-bacteria symbiotic biofilm system to treat food and domestic wastewater while harvesting microalgal biomass.}, } @article {pmid37984030, year = {2023}, author = {Byeon, CH and Kinney, T and Saricayir, H and Srinivasa, S and Wells, MK and Kim, W and Akbey, Ü}, title = {Tapping into the native Pseudomonas bacterial biofilm structure by high-resolution multidimensional solid-state NMR.}, journal = {Journal of magnetic resonance (San Diego, Calif. : 1997)}, volume = {357}, number = {}, pages = {107587}, doi = {10.1016/j.jmr.2023.107587}, pmid = {37984030}, issn = {1096-0856}, abstract = {We present a multidimensional magic-angle spinning (MAS) solid-state NMR (ssNMR) study to characterize native Pseudomonas fluorescens colony biofilms at natural abundance without isotope-labelling. By using a high-resolution INEPT-based 2D [1]H-[13]C ssNMR spectrum and thorough peak deconvolution at the 1D ssNMR spectra, approximately 80/134 (in 1D/2D) distinct biofilm chemical sites were identified. We compared CP and INEPT [13]C ssNMR spectra to differentiate signals originating from the mobile and rigid fractions of the biofilm, and qualitatively determined dynamical changes by comparing CP buildup behaviors. Protein and polysaccharide signals were differentiated and identified by utilizing FapC protein signals as a template, a biofilm forming functional amyloid from Pseudomonas. We identified several biofilm polysaccharide species such as glucose, mannan, galactose, heptose, rhamnan, fucose and N-acylated mannuronic acid by using [1]H and [13]C chemical shifts obtained from the 2D spectrum. To our knowledge, this study marks the first high-resolution multidimensional ssNMR characterization of a native bacterial biofilm. Our experimental pipeline can be readily applied to other in vitro biofilm model systems and natural biofilms and holds the promise of making a substantial impact on biofilm research, fostering new ideas and breakthroughs to aid in the development of strategic approaches to combat infections caused by biofilm-forming bacteria.}, } @article {pmid37983256, year = {2023}, author = {Gupta, A and Luong, JHT and Gedanken, A}, title = {Zirconium-Coated β-Cyclodextrin Nanomaterials for Biofilm Eradication.}, journal = {ACS applied bio materials}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsabm.3c00679}, pmid = {37983256}, issn = {2576-6422}, abstract = {Under alkaline treatment, zirconyl chloride (ZrOCl2.8H2O) became a zirconia gel and formed a stable complex with beta-cyclodextrin (βCD). This complex was highly active in reactive oxygen species (ROS) formation via H2O2 decomposition. Its surface with numerous hydroxyl groups acts as an ionic sponge to capture the charged reaction intermediates, including superoxide (O2[-•]) and the hydroxyl radical ([•]OH). ROS, especially [•]OH radicals, are harmful to living microorganisms because of their kinetic instability, high oxidation potential, and chemical nonselectivity. Therefore, [•]OH radicals can engage in fast reactions with virtually any adjacent biomolecule. With H2O2, the complex with cationic and hydrophobic moieties interacted with the anionic bacterial membrane of two Gram-positive (Staphylococcus aureus and S. epidermidis) and two Gram-negative (Escherichia coli and Klebsiella pneumoniae) strains. The Zr-βCD-H2O2 also eradicated more than 99% of the biofilm of these four pathogens. Considering the difficult acquisition of resistance to the oxidation of [•]OH, the results suggested that this βCD-based nanomaterial might be a promising agent to target both drug-resistant pathogens with no cytotoxicity and exceptional antimicrobial activity.}, } @article {pmid37982962, year = {2023}, author = {Qiao, Z and Guo, X and Wang, T and Wei, J and Liu, Y and Ma, Y and Lü, X}, title = {Effects of Sub-Minimum Inhibitory Concentrations of Bacteriocin BM173 on Listeria Monocytogenes Biofilm Formation.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {37982962}, issn = {1867-1314}, support = {222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; 222102110243//Science and Technology Development Plan Project of Henan province, China/ ; XKPY-2022005//Science and technology incubation fund of Huanghuai University/ ; XKPY-2022005//Science and technology incubation fund of Huanghuai University/ ; 232300420217//Natural Science Foundation of Henan Province, China/ ; 232300420217//Natural Science Foundation of Henan Province, China/ ; 23A550018//Key Scientific Research Project of Colleges and Universities in Henan Province/ ; 23A550018//Key Scientific Research Project of Colleges and Universities in Henan Province/ ; }, abstract = {Listeria monocytogenes is a significant foodborne pathogen that can form biofilms on various food processing surfaces, thereby enhancing resistance to disinfectants and exacerbating harm to human health. Previous studies have indicated that bacteriocin BM173 exhibits antibacterial and antibiofilm activities. In the current study, our aim was to assess the inhibitory mode of action of sub-inhibitory concentrations (SICs, 1/32 × MIC and 1/16 × MIC) of BM173 on the biofilm formation L. monocytogenes. Crystal violet staining assay revealed that SICs of BM173 significantly inhibit L. monocytogenes biofilm formation. Furthermore, the results of swimming motility assay, plate count, ruthenium red staining, and scanning electron microscopy (SEM) revealed that SICs of BM173 could effectively reduce the movement, cell adhesion, and exopolysaccharide (EPS) production of L. monocytogenes, thereby inhibiting biofilm formation. Real-time quantitative PCR analyses further demonstrated that SICs of BM173 down-regulated the expression of biofilm-associated genes, including those encoding adhesion, virulence factors, and quorum sensing. Additionally, SICs of BM173 effectively reduced the biofilm formation of L. monocytogenes on the surfaces of three food-grade materials (glass, stainless steel, and silicone) at 4 and 25 °C. These outcomes suggest that BM173 holds great potential for development as a promising food preservative for application in the food industry.}, } @article {pmid37981154, year = {2023}, author = {Vercauteren, M and Lambert, S and Hoogerwerf, E and Janssen, CR and Asselman, J}, title = {Microplastic-specific biofilm growth determines the vertical transport of plastics in freshwater.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {168399}, doi = {10.1016/j.scitotenv.2023.168399}, pmid = {37981154}, issn = {1879-1026}, abstract = {Understanding the sinking behavior of microplastics in freshwater is essential for assessing their environmental impact, guiding research efforts, and formulating effective policies to mitigate plastic pollution. Sinking behavior is a complex process driven by plastic density, environmental factors and particle characteristics. Moreover, the growth of biological entities on the plastic surface can affect the total density of the microplastics and thus influence the sinking behavior. Yet, our understanding of these processes in freshwater is still limited. Our research thus focused on studying biofilm growth on microplastics in freshwater. Therefore, we evaluated biofilm growth on five different polymer types (both microplastic particles and plates) which were incubated in freshwater for 63 days in a controlled laboratory setting. Biofilm growth (mass-based) was used to compare biofilm growth between polymer types, surface roughness and study the changes over time. Understanding the temporal aspect of biofilm growth enabled us to refine calculations on the predicted effect of biofilm growth on the settling behavior in freshwater. The results showed that biofilm formation is polymer-specific but also affected by surface roughness, with a rougher surface promoting biofilm growth. For PET and PS, biofilm tended to grow exponentially during 63 days of incubation. Based on our calculations, biofilm growth did affect the sinking behavior differently based on the polymer type, size and density. Rivers can function as sinks for some particles such as large PET particles. Nevertheless, for others, the likelihood of settling within river systems appears limited, thereby increasing the probability of their transit to estuarine or oceanic environments under hydrometeorological influences. While the complexity of biofilm dynamics on plastic surfaces is not fully understood, our findings help to elucidate the effect of biofilms on the vertical behavior of microplastics in freshwater systems hereby offering knowledge to interpret observed patterns in environmental plastic concentrations.}, } @article {pmid37980361, year = {2023}, author = {Cheng, J and Gan, G and Zheng, S and Zhang, G and Zhu, C and Liu, S and Hu, J}, title = {Biofilm heterogeneity-adaptive photoredox catalysis enables red light-triggered nitric oxide release for combating drug-resistant infections.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {7510}, pmid = {37980361}, issn = {2041-1723}, mesh = {Animals ; Mice ; *Nitric Oxide/pharmacology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Ciprofloxacin/pharmacology ; Biofilms ; *Anti-Infective Agents/pharmacology ; Pseudomonas aeruginosa/physiology ; Microbial Sensitivity Tests ; }, abstract = {The formation of biofilms is closely associated with persistent and chronic infections, and physiological heterogeneity such as pH and oxygen gradients renders biofilms highly resistant to conventional antibiotics. To date, effectively treating biofilm infections remains a significant challenge. Herein, we report the fabrication of micellar nanoparticles adapted to heterogeneous biofilm microenvironments, enabling nitric oxide (NO) release through two distinct photoredox catalysis mechanisms. The key design feature involves the use of tertiary amine (TA) moieties, which function as sacrificial agents to avoid the quenching of photocatalysts under normoxic and neutral pH conditions and proton acceptors at acidic pH to allow deep biofilm penetration. This biofilm-adaptive NO-releasing platform shows excellent antibiofilm activity against ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA) biofilms both in vitro and in a mouse skin infection model, providing a strategy for combating biofilm heterogeneity and biofilm-related infections.}, } @article {pmid37979739, year = {2023}, author = {Alasiri, A and Soltane, R and Taha, MN and Abd El-Aleam, RH and Alshehri, F and Sayed, AM}, title = {Bakuchiol inhibits Pseudomonas aeruginosa's quorum sensing-dependent biofilm formation by selectively inhibiting its transcriptional activator protein LasR.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128025}, doi = {10.1016/j.ijbiomac.2023.128025}, pmid = {37979739}, issn = {1879-0003}, abstract = {In the present study, we characterized Bakuchiol (Bak) as a new potent quorum sensing (QS) inhibitor against Pseudomonas aeruginosa biofilm formation. Upon extensive in vitro investigations, Bak was found to suppress the P. aeruginosa biofilm formation (75.5 % inhibition) and its associated virulence factor e.g., pyocyanin and rhamnolipids (% of inhibition = 71.5 % and 66.9 %, respectively). Upon LuxR-type receptors assay, Bak was found to selectively inhibit P. aeruginosa's LasR in a dose-dependent manner. Further in-depth molecular investigations (e.g., sedimentation velocity and thermal shift assays) revealed that Bak destabilized LasR upon binding and disrupted its functioning quaternary structure (i.e., the functioning dimeric form). The subsequent modeling and molecular dynamics (MD) simulations explained in more molecular detail how Bak interacts with LasR and how it can induce its dimeric form disruption. In conclusion, our study identified Bak as a potent and specific LasR antagonist that should be widely used as a chemical probe of QS in P. aeruginosa, offering new insights into LasR antagonism processes. The new findings shed light on the cryptic world of LuxR-type QS in this important opportunistic pathogen.}, } @article {pmid37979131, year = {2023}, author = {Azzam, A and Shawky, RM and El-Mahdy, TS}, title = {Sub-inhibitory concentrations of ceftriaxone induce morphological alterations and PIA-independent biofilm formation in Staphylococcus aureus.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37979131}, issn = {1678-4405}, abstract = {The exposure of bacteria to sub-inhibitory concentrations of antibiotics is of biological significance since it can occur in vivo under many circumstances, including low-dose treatment, poor adherence to a regimen, poor drug penetration, drug-drug interactions, and antibiotic resistance of the pathogen. In this study, we investigated the effects of subinhibitory concentrations of four antibiotics: ampicillin, ceftriaxone, gentamicin, and norfloxacin, which are commonly used in clinical settings and on cell morphology and biofilm formation in Staphylococcus aureus as one of the leading causes of nosocomial and biofilm-associated infections. Nine clinical S. aureus biofilm-producing isolates and two known biofilm-producing reference strains, S. aureus ATCC 29213 and S. aureus ATCC 6538, were used in this study. Sub-MICs of beta-lactam antibiotics (ampicillin and ceftriaxone) significantly induced biofilm formation in S. aureus ATCC 29213 and S. aureus ATCC 6538 and in six clinical isolates out of the nine selected isolates when compared with the antibiotic-free control group (P < 0.05), with an approximately 2- to 2.5-fold increase. Gentamicin and norfloxacin induced biofilms in S. aureus ATCC 29213 and S. aureus ATCC 6538, while gentamicin and norfloxacin induced biofilms only in three and two of the nine tested isolates, respectively (P < 0.05). The chemical nature of the biofilm matrix produced by half the MIC of ceftriaxone in the six isolates that showed increased biofilm was all non-polysaccharide in composition (PIA-independent). Gene expression of biofilm-encoding genes atl and sarA in biofilms of the two tested strains (S. aureus ATCC 6538) and clinical strain (S. aureus 16) showed a significant upregulation after exposure to half MIC of ceftriaxone. Additionally, the bacterial cell morphological changes in planktonic cells caused by half MIC of ceftriaxone were evaluated by scanning electron microscopy, which demonstrated a significant cell enlargement when compared with the antibiotic-free control (P < 0.05), and some deformed cells were also noticed. In S. aureus clinical isolates, sub-MICs of ampicillin, ceftriaxone, gentamicin, and norfloxacin may stimulate substantial production of biofilm, which could have important clinical significance and make infection treatment challenges. Further, in vivo research is needed to fully comprehend how sub-MIC of antibiotics can affect biofilm formation in clinical settings. Additionally, more research is required to reveal the clinical implications of the morphological alterations in S. aureus brought on by exposure to ceftriaxone at concentrations below its MIC.}, } @article {pmid37978089, year = {2023}, author = {Kumar, A and Saha, SK and Banerjee, P and Prasad, K and Sengupta, TK}, title = {Antibiotic-Induced Biofilm Formations in Pseudomonas aeruginosa Strains KPW.1-S1 and HRW.1-S3 are Associated with Increased Production of eDNA and Exoproteins, Increased ROS Generation, and Increased Cell Surface Hydrophobicity.}, journal = {Current microbiology}, volume = {81}, number = {1}, pages = {11}, pmid = {37978089}, issn = {1432-0991}, abstract = {Pseudomonas aeruginosa is a medically important opportunistic pathogen due to its intrinsic ability to form biofilms on different surfaces as one of the defense mechanisms for survival. The fact that it can form biofilms on various medical implants makes it more harmful clinically. Although various antibiotics are used to treat Pseudomonas aeruginosa infections, studies have shown that sub-MIC levels of antibiotics could induce Pseudomonas biofilm formation. The present study thus explored the effect of the aminoglycoside antibiotic gentamicin on the biofilm dynamics of two Pseudomonas aeruginosa strains KPW.1-S1 and HRW.1-S3. Biofilm formation was found to be increased in the presence of increased concentrations of gentamicin. Confocal, scanning electron microscopy, and other biochemical tests deduced that biofilm-forming components exoproteins, eDNA, and exolipids as exopolymeric substances in Pseudomonas aeruginosa biofilms were increased in the presence of gentamicin. An increase in reactive oxygen species generation along with increased cell surface hydrophobicity was also seen for both strains when treated with gentamicin. The observed increase in the adherence of the cells accompanied by the increase in the components of exopolymeric substances may have largely contributed to the increased biofilm production by the Pseudomonas aeruginosa strains under the stress of the antibiotic treatment.}, } @article {pmid37977856, year = {2023}, author = {Perez-Alba, E and Flores-Treviño, S and Villarreal-Salazar, V and Bocanegra-Ibarias, P and Vilchez-Cavazos, F and Camacho-Ortiz, A}, title = {Planktonic and Biofilm states of Staphylococcus aureus isolated from bone and joint infections and the in vitro effect of orally available antibiotics.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad258}, pmid = {37977856}, issn = {1365-2672}, abstract = {AIMS: To demonstrate the in vitro activity of orally available antibiotics against Staphylococcus aureus isolated from bone or orthopedic implant materials. The biofilm eradication of the combination of three antibiotics was also assessed.

METHODS AND RESULTS: Clinical isolates from orthopedic infection samples were collected, and S. aureus isolates were classified according to their biofilm production and composition. Almost all S. aureus isolates (n=36, 97.3%) produced biofilm and the major biofilm components were polysaccharides. Antimicrobial susceptibility was determined in planktonic (minimal inhibitory concentration [MIC]) and biofilm cells (minimal biofilm eradication concentration [MBEC]) using the MBEC Calgary Device. Overall, the MBEC ranged higher than the MIC. When combined at borderline susceptible concentrations, moxifloxacin-rifampin and doxycycline-rifampin were both able to eradicate biofilms in a third of the strains whereas the doxycycline-moxifloxacin combination proved ineffective at eradicating biofilm, inhibiting it only in three strains.

CONCLUSIONS: We propose rifampin in combination with moxifloxacin or doxycycline for the design of clinical trials of bone and/or orthopedic device infection without proper debridement or material retention.}, } @article {pmid37977482, year = {2023}, author = {Rohatgi, N and Ganapathy, D and Sathishkumar, P}, title = {Eradication of Pseudomonas aeruginosa biofilm using quercetin-mediated copper oxide nanoparticles incorporated electrospun polycaprolactone nanofibrous scaffold.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106453}, doi = {10.1016/j.micpath.2023.106453}, pmid = {37977482}, issn = {1096-1208}, abstract = {Pseudomonas aeruginosa is an opportunistic bacterial pathogen that form biofilms in chronic wounds and is difficult to treat with standard treatment methods. In the present study, flavonoid quercetin-mediated CuONPs (Que-CuONPs) were successfully synthesized and incorporated in the electrospun polycaprolactone (Que-CuONPs-PCL) nanofibrous membrane to eradicate the burn wound infection causing P. aeruginosa biofilm. The fabricated scaffold Que-CuONPs-PCL was characterized using HR-SEM, EDX, XRD, and FTIR. The synthesized Que-CuONPs appeared as spherical in shape with the average size of 36 nm. The crystallite size of the synthesized CuONPs was calculated as 23 nm. Antibacterial activity shows that the ZOI and MIC of Que-CuONPs against P. aeruginosa was found to be 20 mm and 5 μg/mL, respectively. Antibiofilm assay indicates the pre-formed P. aeruginosa biofilm was completely eradicated by Que-CuONPs at 8-MIC. The Que-CuONPs-PCL nanofibrous scaffolds exhibits less cytotoxic effects on mouse fibroblast (L929) cells. Finally, this study highlights the fabricated Que-CuONPs-PCL nanofibrous scaffolds exhibits excellent antibiofilm effect against P. aeruginosa biofilm with a great biocompatibility.}, } @article {pmid37977464, year = {2023}, author = {Cui, M and Li, S and Ma, X and Wang, J and Wang, X and Stott, NE and Chen, J and Zhu, J and Chen, J}, title = {Sustainable Janus lignin-based polyurethane biofoams with robust antibacterial activity and long-term biofilm resistance.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128088}, doi = {10.1016/j.ijbiomac.2023.128088}, pmid = {37977464}, issn = {1879-0003}, abstract = {Conventional antibiotic therapies have been becoming less efficient due to increasingly, and sometimes fully, antibiotic-resistant bacterial strains, sometimes known as "superbacteria" or "superbugs." Thus, novel antibacterial materials to effectively inhibit or kill bacteria are crucial for humanity. As a broad-spectrum antimicrobial agent, silver nanoparticles (Ag NPs) have been the most widely commercialized of biomedical materials. However, long-term use of significant amounts of Ag NPs can be potentially harmful to human health through a condition known as argyria, in addition to being toxic to many environmental systems. It is, thus, highly necessary to reduce the amount of Ag NPs employed in medical treatments while also ensuring maintenance of antimicrobial properties, in addition to reducing the overall cost of treatment for humanitarian utilization. For this purpose, naturally sourced antimicrobial polylysine (PL) is used to partially replace Ag NPs within the materials composition. Accordingly, a series of PL, Ag NPs, and lignin-based polyurethane (LPU) composite biofoams (LPU-PL-Ag) were prepared. These proposed composite biofoams, containing at most only 2 % PL and 0.03 % Ag NPs, significantly inhibited the growth of both Gram-positive and Gram-negative bacteria within 1 h and caused irreversibly destructive bactericidal effects. Additionally, with a layer of polydimethylsiloxane (PDMS) on the surface, PDMS-LPU-PL(2 %)-Ag(0.03 %) can effectively prevent bacterial adhesion with a clearance rate of about 70 % for both bacterial biofilms within three days and a growth rate of more than 80 % for mouse fibroblasts NIH 3 T3. These lignin-based polyurethane biofoam dressings, with shorter antiseptic sterilization times and broad-spectrum antibacterial effects, are extremely advantageous for infected wound treatment and healing in clinical use.}, } @article {pmid37976973, year = {2023}, author = {Mitsuwan, W and Intongead, S and Saengsawang, P and Romyasamit, C and Narinthorn, R and Nissapatorn, V and Pereira, ML and Paul, AK and Wongtawan, T and Boripun, R}, title = {Occurrence of multidrug resistance associated with extended-spectrum β‑lactamase and the biofilm forming ability of Escherichia coli in environmental swine husbandry.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {103}, number = {}, pages = {102093}, doi = {10.1016/j.cimid.2023.102093}, pmid = {37976973}, issn = {1878-1667}, abstract = {Extended-spectrum beta-lactamase (ESBL) production and biofilm formation are mechanisms employed by Escherichia coli to resist beta-lactam antibiotics. Thus, we aimed to examine antibiotic resistance associated with ESBL production and biofilm formation in E. coli isolates from swine farms in Southern Thailand. In total, 159 E. coli isolates were obtained, with 44 isolates identified as ESBL producers, originating from feces (18.87 %) and wastewater (8.80 %) samples. All ESBL-producing strains exhibited resistance to ampicillin (100 %), followed by the cephalosporin group (97.73 %) and tetracycline (84.09 %). Multidrug resistance was observed in 17 isolates (38.63 %). Among the isolates from feces samples, the blaGES gene was the most prevalent, detected in 90 % of the samples, followed by blaCTX-M9 (86.67 %) and blaCTX-M1 (66.67 %), respectively. In the bacteria isolated from wastewater, both blaGES and blaCTX-M9 genes were the predominant resistance genes, detected in 100 % of the isolates, followed by blaCTX-M1 (64.29 %) and blaTEM (50 %), respectively. Strong biofilm formation was observed in 11 isolates (36.67 %) from feces and 4 isolates (25.57 %) from wastewater samples. Notably, nearly 100 % of ESBL-producing strains isolated from feces tested positive for both pgaA and pgaC genes, which play a role in intracellular adhesion and biofilm production. These findings contribute to the understanding and potential control of ESBL-producing E. coli, and the dissemination of antibiotic resistance and biofilm-related genes in swine farms.}, } @article {pmid37976648, year = {2023}, author = {Song, Z and Hao, S and Zhang, L and Fan, X and Peng, Y}, title = {High-rate nitrogen removal by partial nitritation/anammox with a single-stage membrane-aerated biofilm reactor.}, journal = {Journal of environmental management}, volume = {349}, number = {}, pages = {119581}, doi = {10.1016/j.jenvman.2023.119581}, pmid = {37976648}, issn = {1095-8630}, abstract = {In this study, a membrane aerated biofilm reactor (MABR) coupled partial nitritation/anammox (PN/A) system was established for high-rate nitrogen removal. Results showed that the nitrogen removal efficiency of 90.34% was finally obtained when influent ammonia increased from 150 mg L[-1] to 300 mg L[-1]. Based on the fluorescence spectroscopy technology, the raised hydrophobicity tryptophan in extracellular polymeric substances (EPS) promoted biofilm formation and bacteria aggregation. 16S rRNA gene amplicon sequencing revealed that the relative abundance of AOB and AnAOB was also enhanced by ammonia (Nitrosomonas and Candidatus Brocadia increased by 6.02 % and 10.06 % in biofilm, respectively), which further facilitated nitrogen removal efficiency. Furthermore, the key functional genes involved in partial nitritation and anammox, especially hao and nirK, up-regulated by 1.31 and 1.26 times, respectively, accelerating the electron generation and consumption. Therefore, raising influent ammonia content intensified microbial electron transfer behavior and high-rate nitrogen metabolism.}, } @article {pmid37974055, year = {2023}, author = {Roese, KHC and Torlone, C and Cooper, LA and Esposito, L and Deveau, AM and Röse, USR and Burkholder, KM}, title = {Pyrogallol impairs staphylococcal biofilm formation via induction of bacterial oxidative stress.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad270}, pmid = {37974055}, issn = {1365-2672}, abstract = {AIMS: To examine the effect of the phenolic compound pyrogallol on staphylococcal biofilm formation.

METHODS AND RESULTS: In crystal violet biofilm assays, pyrogallol reduced biofilm formation in S. epidermidis ATCC 35984, S. epidermidis NRRL-B41021, S. aureus USA300 and S. aureus Newman, without significantly impairing bacterial viability. Pyrogallol-mediated impairment of biofilm formation was likely due to induction of bacterial oxidative stress, as its effect was greater in catalase-deficient versus WT S. aureus, and biofilm production was rescued by exogenous catalase. The effect of pyrogallol on staphylococcal biofilm formation mirrored that of the known oxidant hydrogen peroxide, which also reduced biofilm formation in a dose-dependent manner.

CONCLUSIONS: Pyrogallol reduces biofilm formation in S. aureus and S. epidermidis in a mechanism involving induction of bacterial oxidative stress.}, } @article {pmid37974052, year = {2023}, author = {Ruiz, MJ and Sirini, NE and Stegmayer, MÁ and Soto, LP and Zbrun, MV and Olivero, CR and Werning, ML and Acosta, FF and Signorini, ML and Frizzo, LS}, title = {Inhibitor activity of lactiplantibacillus plantarum LP5 on thermotolerant campylobacter with different biofilm-forming capacities.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad267}, pmid = {37974052}, issn = {1365-2672}, abstract = {AIMS: To evaluate the biofilm-forming capacity of thermotolerant Campylobacter (TC) strains from poultry production and to analyse the inhibitory capacity of Lactiplantibacillus plantarum LP5 against TC on different materials.

METHODS AND RESULTS: Biofilm-forming capacity by Campylobacter jejuni and Campylobacter coli was analysed by cell adhesion in polystyrene plates. TC were classified as non-biofilm-forming (NBF, 1.3%), weak biofilm-forming (WBF, 68.4%), moderate biofilm-forming (MBF, 27.6%), and strong biofilm-forming (SBF, 2.7%). The inhibitory capacity of L. plantarum LP5 against TC was tested on stainless-steel, nylon, aluminium, and glass disks (treated group) and compared with biofilm-forming TC (control group). L. plantarum LP5 was inoculated, and then TC. Biofilm was removed in both experimental groups and TC and LP5 bacterial counts were performed. The L. plantarum LP5 presence reduced the formation of TC biofilm (P < 0.001). The material type and strain category influenced biofilm formation, with stainless-steel and the SBF strain being the material and TC having the highest adhesion (P < 0.001). L. plantarum LP5 formed similar biofilm on all materials (P = 0.823).

CONCLUSIONS: This trial showed very promising results; L. plantarum LP5 could be incorporated as a bio-protector of TC on different surfaces.}, } @article {pmid37973467, year = {2023}, author = {Zhou, Y and Huang, J and Wang, G and Zhai, Z and Ahmed, MU and Xia, X and Liu, C and Jin, Y and Pan, X and Huang, Y and Wu, C and Zhang, X}, title = {Polymyxin B sulfate inhalable microparticles with high-lectin-affinity sugar carriers for efficient treatment of biofilm-associated pulmonary infections.}, journal = {Science bulletin}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.scib.2023.11.004}, pmid = {37973467}, issn = {2095-9281}, abstract = {Pulmonary infections caused by multidrug-resistant bacteria have become a significant threat to human health. Bacterial biofilms exacerbate the persistence and recurrence of pulmonary infections, hindering the accessibility and effectiveness of antibiotics. In this study, a dry powder inhalation (DPI) consisting of polymyxin B sulfate (PMBS) inhalable microparticles and high-lectin-affinity (HLA) sugar (i.e., raffinose) carriers was developed for treating pulmonary infections and targeting bacterial lectins essential for biofilm growth. The formulated PMBS-HLA DPIs exhibited particle sizes of approximately 3 μm, and surface roughness varied according to the drug-to-carrier ratio. Formulation F5 (PMBS: raffinose = 10:90) demonstrated the highest fine particle fraction (FPF) value (64.86%), signifying its substantially enhanced aerosol performance, potentially attributable to moderate roughness and smallest mass median aerodynamic particle size. The efficacy of PMBS-HLA DPIs in inhibiting biofilm formation and eradicating mature biofilms was significantly improved with the addition of raffinose, suggesting the effectiveness of lectin-binding strategy for combating bacterial biofilm-associated infections. In rat models with acute and chronic pulmonary infections, F5 demonstrated superior bacterial killing and amelioration of inflammatory responses compared to spray-dried PMBS (F0). In conclusion, our HLA carrier-based formulation presents considerable potential for the efficient treatment of multidrug-resistant bacterial biofilm-associated pulmonary infections.}, } @article {pmid37973189, year = {2023}, author = {Xia, FW and Guo, BW and Zhao, Y and Wang, JL and Chen, Y and Pan, X and Li, X and Song, JX and Wan, Y and Feng, S and Wu, MY}, title = {Type I Photosensitizer Targeting Glycans: Overcoming Biofilm Resistance by Inhibiting The Two-Component System, Quorum Sensing, And Multidrug Efflux.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2309797}, doi = {10.1002/adma.202309797}, pmid = {37973189}, issn = {1521-4095}, abstract = {Stubborn biofilm infections pose serious threats to human health due to the persistence, recurrence, and dramatically magnified antibiotic resistance. Photodynamic therapy has emerged as a promising approach to combat biofilm. Nevertheless, how to inhibit the bacterial signal transduction system and the efflux pump to conquer biofilm recurrence and resistance remains a challenging and unaddressed issue. Herein, we developed a boric acid-functionalized lipophilic cationic type I photosensitizer, ACR-DMP, which efficiently generates •OH to overcome the hypoxic microenvironment and photodynamically eradicates methicillin-resistant Staphylococcus aureus (MRSA) and biofilms. Furthermore, it not only alters membrane potential homeostasis and osmotic pressure balance due to its strong binding ability with plasma membrane but also inhibits quorum sensing (QS) and the two-component system (TCS), reduces virulence factors, and regulates the activity of the drug efflux pump attributed to the glycans targeting ability, helping to prevent biofilm recurrence and conquer biofilm resistance. In vivo, ACR-DMP successfully obliterates MRSA biofilms attached to implanted medical catheters, alleviates inflammation, and promotes vascularization, thereby combating infections and accelerating wound healing. This work not only provides an efficient strategy to combat stubborn biofilm infections and bacterial multidrug resistance but also offers systematic guidance for the rational design of next-generation advanced antimicrobial materials. This article is protected by copyright. All rights reserved.}, } @article {pmid37973062, year = {2023}, author = {Diop, S and Pons, S and Kapandji, N and Kallel, H and Woerther, PL and Mekontso-Dessap, A and Rodriguez, C and Mongardon, N and Roujansky, A and Mounier, R}, title = {Biofilm Assessment and Metagenomic Analysis of Venoarterial Extracorporeal Membrane Oxygenation Cannulas and Membrane Oxygenators.}, journal = {ASAIO journal (American Society for Artificial Internal Organs : 1992)}, volume = {}, number = {}, pages = {}, doi = {10.1097/MAT.0000000000002095}, pmid = {37973062}, issn = {1538-943X}, abstract = {Venoarterial extracorporeal membrane oxygenation (VA-ECMO) exposes the patient to infectious complications related to the cannulas or the site of insertion. The aim of the current study was to investigate and compare the prevalence of cannula and membrane oxygenators colonization using three different methods: microbiological culture, scanning electron microscopy, and metagenomic (rRNA 16S analysis). A monocentric prospective study was conducted between December 2017 and June 2018. Consecutive patients undergoing VA-ECMO support for refractory cardiac arrest or cardiogenic shock were included. Ten patients were included with a median age of 64 (52-62) years. Venoarterial extracorporeal membrane oxygenation was inserted for refractory cardiac arrest in five (50%), cardiogenic shock in four (40%), and self-poisoning in one (10%) cases. Microbiological culture of all (8/8, 100%) membrane oxygenators was negative, whereas all (10/10, 100%) were colonized by biofilm, and eight (8/9, 89%) presented bacterial DNA. Three (3/9, 33%) arterial and venous cannulas were positive in culture and seven (7/9, 78%) were colonized by biofilm, respectively. Seven (7/9, 78%) arterial and four (4/9, 44%) venous cannulas presented bacterial DNA. Colonization of cannulas and membranes is more frequent when assessed by electron microscopy or metagenomic analysis than with culture. Membrane oxygenators are more often colonized than cannulas.}, } @article {pmid37972742, year = {2023}, author = {Wang, W and Liu, JS and Zhou, JW and Jia, AQ}, title = {Synergistic effect of kanamycin and amikacin with setomimycin on biofilm formation inhibition of Listeria monocytogenes.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106447}, doi = {10.1016/j.micpath.2023.106447}, pmid = {37972742}, issn = {1096-1208}, abstract = {Listeria monocytogenes, a foodborne pathogen that causes listeriosis with high fatality rate, exhibits multidrug resistance (MDR) known to be progressively increasing. Alternative antibacterial strategies are in high demand for treating this well-known pathogen. Anti-biofilm and anti-virulence strategies are being explored as novel approaches to treat bacterial infections. In this study, one rare antibacterial named setomimycin was isolated from Streptomyces cyaneochromogenes, which showed potent antibacterial activity against L. monocytogenes. Next, the inhibition of biofilm formation and listeriolysin O (LLO) production against L. monocytogenes were investigated at sub-minimal inhibitory concentrations (sub-MICs) of setomimycin alone or combined with kanamycin or amikacin. Crystal violet staining confirmed that setomimycin combining with kanamycin or amikacin could dramatically reduce the formation of biofilm against L. monocytogenes at sub-MICs, which was further evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). In the meantime, setomimycin could significantly suppress the secretion of LLO at sub-MICs. To elucidate the potential biofilms and virulence factors inhibiting mechanism, the transcription of genes associated with biofilms and main virulence factors, such as LLO, flagellum, metalloprotease, were suppressed by setomimycin at sub-MICs. Hence, the study provided a deep insight into setomimycin as an alternative antibacterial agent against L. monocytogenes.}, } @article {pmid37971263, year = {2023}, author = {Sun, X and Xie, J and Zheng, D and Xia, R and Wang, W and Xun, W and Huang, Q and Zhang, R and Kovács, ÁT and Xu, Z and Shen, Q}, title = {Metabolic interactions affect the biomass of synthetic bacterial biofilm communities.}, journal = {mSystems}, volume = {}, number = {}, pages = {e0104523}, doi = {10.1128/msystems.01045-23}, pmid = {37971263}, issn = {2379-5077}, abstract = {Co-occurrence network analysis is an effective tool for predicting complex networks of microbial interactions in the natural environment. Using isolates from a rhizosphere, we constructed multi-species biofilm communities and investigated co-occurrence patterns between microbial species in genome-scale metabolic models and in vitro experiments. According to our results, metabolic exchanges and resource competition may partially explain the co-occurrence network analysis results found in synthetic bacterial biofilm communities.}, } @article {pmid37970886, year = {2023}, author = {Ev, LD and Poloni, JF and Damé-Teixeira, N and Arthur, RA and Corralo, DJ and Henz, SL and DO, T and Maltz, M and Parolo, CCF}, title = {Biofilm dysbiosis and caries activity: a surface or an individual issue?.}, journal = {Journal of applied oral science : revista FOB}, volume = {31}, number = {}, pages = {e20230214}, doi = {10.1590/1678-7757-2023-0214}, pmid = {37970886}, issn = {1678-7765}, abstract = {OBJECTIVE: This study aimed to analyze the functional profile of supragingival biofilm from sound (CAs), active (CAa), and inactive (CAi) enamel caries lesions from caries-active individuals to provide insights into the diversity of biological processes regarding biofilm dysbiosis.

METHODOLOGY: A metatranscriptome analysis was performed in biofilm samples collected from five caries-active individuals. Total RNA was extracted, and the microbial cDNAs were obtained and sequenced (Illumina HiSeq3000). Trimmed data were submitted to the SqueezeMeta pipeline in the co-assembly mode for functional analysis and further differential gene expression analysis (DESeq2).

RESULTS: Bioinformatics analysis of mRNAs revealed a similar functional profile related to all analyzed conditions (CAa, CAi, and CAs). However, active and inactive surfaces share up-regulated genes (gtsA; qrtT; tqsA; pimB; EPHX1) related to virulence traits that were not overrepresented in sound surfaces. From a functional perspective, what matters most is the individual carious status rather than the surface condition. Therefore, pooling samples from various sites can be carried out using naturally developed oral biofilms but should preferably include carious surfaces.

CONCLUSION: Metatranscriptome data from subjects with caries activity have shown that biofilms from sound, arrested, and active lesions are similar in composition and function.}, } @article {pmid37969760, year = {2023}, author = {Elgamoudi, BA and Korolik, V}, title = {A Guideline for Assessment and Characterization of Bacterial Biofilm Formation in the Presence of Inhibitory Compounds.}, journal = {Bio-protocol}, volume = {13}, number = {21}, pages = {e4866}, pmid = {37969760}, issn = {2331-8325}, abstract = {Campylobacter jejuni, a zoonotic foodborne pathogen, is the worldwide leading cause of acute human bacterial gastroenteritis. Biofilms are a significant reservoir for survival and transmission of this pathogen, contributing to its overall antimicrobial resistance. Natural compounds such as essential oils, phytochemicals, polyphenolic extracts, and D-amino acids have been shown to have the potential to control biofilms formed by bacteria, including Campylobacter spp. This work presents a proposed guideline for assessing and characterizing bacterial biofilm formation in the presence of naturally occurring inhibitory molecules using C. jejuni as a model. The following protocols describe: i) biofilm formation inhibition assay, designed to assess the ability of naturally occurring molecules to inhibit the formation of biofilms; ii) biofilm dispersal assay, to assess the ability of naturally occurring inhibitory molecules to eradicate established biofilms; iii) confocal laser scanning microscopy (CLSM), to evaluate bacterial viability in biofilms after treatment with naturally occurring inhibitory molecules and to study the structured appearance (or architecture) of biofilm before and after treatment.}, } @article {pmid37968960, year = {2023}, author = {Jeong, GJ and Khan, F and Tabassum, N and Kim, YM}, title = {Natural and synthetic molecules with potential to enhance biofilm formation and virulence properties in Pseudomonas aeruginosa.}, journal = {Critical reviews in microbiology}, volume = {}, number = {}, pages = {1-29}, doi = {10.1080/1040841X.2023.2282459}, pmid = {37968960}, issn = {1549-7828}, abstract = {Pseudomonas aeruginosa can efficiently adapt to changing environmental conditions due to its ubiquitous nature, intrinsic/acquired/adaptive resistance mechanisms, high metabolic versatility, and the production of numerous virulence factors. As a result, P. aeruginosa becomes an opportunistic pathogen, causing chronic infection in the lungs and several organs of patients suffering from cystic fibrosis. Biofilm established by P. aeruginosa in host tissues and medical device surfaces has been identified as a major obstruction to antimicrobial therapy. P. aeruginosa is very likely to be closely associated with the various microorganisms in the host tissues or organs in a pathogenic or nonpathogenic behavior. Aside from host-derived molecules, other beneficial and pathogenic microorganisms produce a diverse range of secondary metabolites that either directly or indirectly favor the persistence of P. aeruginosa. Thus, it is critical to understand how P. aeruginosa interacts with different molecules and ions in the host and abiotic environment to produce extracellular polymeric substances and virulence factors. Thus, the current review discusses how various natural and synthetic molecules in the environment induce biofilm formation and the production of multiple virulence factors.}, } @article {pmid37968931, year = {2023}, author = {Li, S and Yang, Q and Cheng, B and Liu, Y and Zhou, S and Ai, X and Dong, J}, title = {Neem oil against Aeromonas hydrophila infection by disrupting quorum sensing and biofilm formation.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2023.2279998}, pmid = {37968931}, issn = {1029-2454}, abstract = {Aeromonas hydrophila is an opportunistic pathogen that can cause a number of infectious diseases in fish and is widely distributed in aquatic environments. Antibiotics are the main approach against A. hydrophila infections, while the emergence of resistant bacteria limits the application of antibiotics. Here, quorum-sensing (QS) was defined as the target and the inhibitory effects of neem oil against QS of A. hydrophila was studied. The results showed that neem oil could dose-dependently reduce aerolysin, protease, lipase, acyl-homoserine lactones (AHLs), biofilm and swarming motility at sub-inhibitory concentrations. Results of real-time PCR demonstrated that neem oil could down-regulate the transcription of aerA, ahyI and ahyR. Moreover, neem oil showed significant protections to A549 cells and a fish infection model. Taken together, these results indicated that neem oil could be chosen as a promising candidate for the treatment of A. hydrophila infections.}, } @article {pmid37968157, year = {2023}, author = {Tran, HH and Watkins, A and Oh, MJ and Babeer, A and Schaer, TP and Steager, E and Koo, H}, title = {Targeting biofilm infections in humans using small scale robotics.}, journal = {Trends in biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tibtech.2023.10.004}, pmid = {37968157}, issn = {1879-3096}, abstract = {The eradication of drug-resistant microbial biofilms remains an unresolved global health challenge. Small-scale robotics are providing innovative therapeutic and diagnostic approaches with high precision and efficacy. These approaches are rapidly moving from proof-of-concept studies to translational biomedical applications using ex vivo, animal, and clinical models. Here, we discuss the fundamental and translational aspects of how microrobots target the infection sites to disrupt the structural and functional traits of biofilms and their antimicrobial resistance mechanisms. We emphasize current approaches of mechanochemical disruption and on-site drug delivery that are supported by in vivo models and preclinical testing, while also highlighting diagnostics potential. We also discuss clinical translation challenges and provide perspectives for development of microrobotics approaches to combat biofilm infections and biofouling in humans.}, } @article {pmid37966644, year = {2023}, author = {Damasceno, DQ and Lafratta, FH and Valentina, LVOD and Armstrong, LCT and Wegbecher, FX}, title = {Microbiological characterization of biofilm from different immobilization structures used in submersed aerobic biofilters in domestic effluent treatment at the city of Joinville, Brazil.}, journal = {Environmental science and pollution research international}, volume = {}, number = {}, pages = {}, pmid = {37966644}, issn = {1614-7499}, abstract = {The objective of this work was to develop a polymeric structure for a biofiltration unit of domestic effluents through microbiological immobilization, capable of promoting the efficient removal of pollutants, meeting local/national Brazilian standards and/or legislation while providing low environmental impact on their production. Four different structures were tested, namely, polypropylene casings without filling material (TF1); polypropylene casings filled with expanded polystyrene grains (TF2); polypropylene casings, filled with polyurethane foam (TF3); and polypropylene casings, filled with polyvinyl chloride pellets (TF4). A flow of 0.216 m[3] d[-1] was applied to the system, and the biofilters operated in sequential batches with a hydraulic retention time of 6 h. The efficiency potential of the four immobilization structures was verified regarding biochemical and chemical oxygen demand, total ammoniacal nitrogen and total phosphorus. Microbiological analysis of the formed biofilm, performed with the 16S library sequencing method, with amplification of the 16S rRNA V3 and V3-V4 genomic regions, showed a high diversity of microbiological colonization in the four immobilization structures, with better results and consequently greater community stability in TF2. It is recommended using the filter bed made up of unfilled casings, followed by the one filled with expanded polystyrene grains.}, } @article {pmid37965865, year = {2023}, author = {Liao, Y and Fatehi, P and Liao, B}, title = {Surface properties of membrane materials and their role in cell adhesion and biofilm formation of microalgae.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/08927014.2023.2280005}, pmid = {37965865}, issn = {1029-2454}, abstract = {In this study, the effects of surface properties of membrane materials on microalgae cell adhesion and biofilm formation were investigated using Chlorella vulgaris and five different types of membrane materials under hydrodynamic conditions. The results suggest that the contact angle (hydrophobicity), surface free energy, and free energy of cohesion of membrane materials alone could not sufficiently elucidate the selectivity of microalgae cell adhesion and biofilm formation on membrane materials surfaces, and membrane surface roughness played a dominant role in controlling biofilm formation rate, under tested hydrodynamic conditions. A lower level of biofilm EPS production was generally associated with a larger amount of biofilm formation. The zeta potential of membrane materials could enhance initial microalgae cell adhesion and biofilm formation through salt bridging or charge neutralization mechanisms.}, } @article {pmid37964901, year = {2023}, author = {Droumpali, A and Liu, Y and Ferrer-Florensa, X and Sternberg, C and Dimaki, M and Andersen, AJC and Strube, ML and Kempen, PJ and Gram, L and Taboryski, R}, title = {Biosynthesis enhancement of tropodithietic acid (TDA) antibacterial compound through biofilm formation by marine bacteria Phaeobacter inhibens on micro-structured polymer surfaces.}, journal = {RSC advances}, volume = {13}, number = {47}, pages = {33159-33166}, pmid = {37964901}, issn = {2046-2069}, abstract = {Although aquaculture is a major player in current and future food production, the routine use of antibiotics provides ample ground for development of antibiotic resistance. An alternative route to disease control is the use of probiotic bacteria such as the marine bacteria Phaeobacter inhibens which produces tropodithietic acid (TDA) that inhibit pathogens without affecting the fish. Improving conditions for the formation of biofilm and TDA-synthesis is a promising avenue for biocontrol in aquaculture. In this study, the biosynthesis of TDA by Phaeobacter inhibens grown on micro-structured polymeric surfaces in micro-fluidic flow-cells is investigated. The formation of biofilms on three surface topographies; hexagonal micro-pit-arrays, hexagonal micro-pillar-arrays, and planar references is investigated. The biomass on these surfaces is measured by a non-invasive confocal microscopy 3D imaging technique, and the corresponding TDA production is monitored by liquid chromatography mass spectrometry (LC-MS) in samples collected from the outlets of the microfluidic channels. Although all surfaces support growth of P. inhibens, biomass appears to be decoupled from total TDA biosynthesis as the micro-pit-arrays generate the largest biomass while the micro-pillar-arrays produce significantly higher amounts of TDA. The findings highlight the potential for optimized micro-structured surfaces to maintain biofilms of probiotic bacteria for sustainable aquacultures.}, } @article {pmid37963503, year = {2023}, author = {Tang, L and Zhang, Z and Ding, W and Tang, J and Deng, X and He, Q and Kong, X and Chen, J and Truong, TMH and Wang, G and Zhu, X and Ding, W}, title = {Preparation, characterization, and Staphylococcus aureus biofilm elimination effect of baicalein-loaded tyrosine/hyaluronic acid/β-cyclodextrin-grafted chitosan nano-delivery system.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {128066}, doi = {10.1016/j.ijbiomac.2023.128066}, pmid = {37963503}, issn = {1879-0003}, abstract = {Staphylococcus aureus (S. aureus) is an important cause of infections associated with implanted medical devices due to the formation of bacterial biofilm, which can prevent the penetration of drugs, thus posing a serious multi-drug resistance. Methicillin-resistant Staphylococcus aureus (MRSA) is one of them. In order to enhance the biofilm elimination effect of Baicalein (BA), a BA-loaded Tyr/HA/CD-CS nano-delivery system was successfully prepared using β-cyclodextrin grafted with chitosan (CD-CS), Hyaluronic Acid (HA), and D-Tyrosine (D-Tyr). The Tyr/HA/CD-CS-BA-NPs have a uniform particle size distribution with a particle size of 238.1 ± 3.06 nm and a PDI of 0.130 ± 0.02. The NPs showed an obvious inhibitory effect on planktonic bacteria with a MIC of 12.5 μg/mL. In vivo and in vitro tests showed that the NPs could enhance the elimination effect of BA on the MRSA biofilm. The results of Confocal Laser Scanning Microscopy (CLSM), Live & Dead Kit, and colony count experiments illustrated that Tyr/HA/CD-CS-BA-NPs could enhance the permeability of drugs to the biofilm and improve the ability to kill the biofilm bacteria, which may be an important mechanism to enhance the elimination of the MRSA biofilm. These findings will help develop new, effective medicaments for treating bacterial biofilm infections.}, } @article {pmid37963459, year = {2023}, author = {Turnau, K and Płachno, BJ and Bień, P and Świątek, P and Dąbrowski, P and Kalaji, H}, title = {Fungal symbionts impact cyanobacterial biofilm durability and photosynthetic efficiency.}, journal = {Current biology : CB}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cub.2023.10.056}, pmid = {37963459}, issn = {1879-0445}, abstract = {Cyanobacteria contribute to over 25% of the world's net primary photosynthetic production and are pivotal in mitigating greenhouse gas emissions.[1] This study unveils a previously unobserved symbiotic relationship between benthic cyanobacteria and fungi that have also adapted to life as a plant endophyte. The interaction suggests an initial phase of lichenization. We isolated Leptolyngbya frigida from the Naracauli stream, which emanates from abandoned Zn industrial waste in Sardinia. Seasonally, L. frigida participates in a biomineralization processes, mitigating the Zn transfer to rivers and, subsequently, the sea.[2][,][3][,][4]L. frigida is a benthic cyanobacterium that establishes a biofilm on the stream bed. Notably, the area predominantly features Juncus acutus. From these roots, endophytic fungi were predominantly isolated as Clonostachys rosea, a fungus recognized for its biocontrol capabilities against plant pathogens. An intriguing observation was made when L. frigida was cultured with C. rosea on a low-carbohydrate agar medium: the fungal mycelium transformed into wall-less forms, a phenomenon not documented previously. In liquid environments, the resulting biofilm first settled at the container's bottom. Even upon rising to the surface, this biofilm remained pigment rich. Concurrently, a secondary biofilm began its formation at the bottom. These fungal-integrated biofilms displayed enhanced resilience and superior photosynthetic performance compared to those without fungal presence. Moreover, the symbiotic relationship significantly amplified O2 emission and CO2 sequestration by the biofilm.}, } @article {pmid37961602, year = {2023}, author = {Kaplan, JB and Florjanczyk, AP and Ochiai, M and Jones, CD and Horswill, AR}, title = {Micrococcal nuclease regulates biofilm formation and dispersal in methicillin-resistant Staphylococcus aureus USA300.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.11.05.565664}, pmid = {37961602}, abstract = {Biofilm formation is an important virulence factor for methicillin-resistant Staphylococcus aureus (MRSA). The extracellular matrix of MRSA biofilms contains significant amounts of double-stranded DNA. MRSA cells also secrete micrococcal nuclease (Nuc1) which degrades double-stranded DNA. In this study we used a nuc1 mutant strain to investigate the role of Nuc1 in MRSA biofilm formation and dispersal. Biofilm was quantitated in microplates using a crystal violet binding assay. Extracellular DNA (eDNA) was isolated from colony biofilms and analyzed by agarose gel electrophoresis. In some experiments, broth or agar was supplemented with sub-MIC amoxicillin to induce biofilm formation. Biofilm erosion was quantitated by culturing biofilms on rods, transferring the rods to fresh broth, and enumerating CFUs that detached from the rods. Biofilm sloughing was investigated by culturing biofilms in glass tubes perfused with broth and measuring the sizes of the detached cell aggregates. We found that a nuc1 mutant strain produced significantly more biofilm and more eDNA than a wild-type strain in both the absence and presence of sub-MIC amoxicillin. nuc1 mutant biofilms grown on rods detached significantly less than wild-type biofilms. Detachment was restored by exogenous DNase or a wild-type nuc1 gene on a plasmid. In the sloughing assay, nuc1 mutant biofilms released cell aggregates that were significantly larger than those released by wild-type biofilms. Our results suggest that Nuc1 modulates biofilm formation, biofilm detachment, and the sizes of detached cell aggregates. These processes may play a role in the spread and subsequent survival of MRSA biofilms during biofilm-related infections.}, } @article {pmid37960038, year = {2023}, author = {Iobbi, V and Parisi, V and Bernabè, G and De Tommasi, N and Bisio, A and Brun, P}, title = {Anti-Biofilm Activity of Carnosic Acid from Salvia rosmarinus against Methicillin-Resistant Staphylococcus aureus.}, journal = {Plants (Basel, Switzerland)}, volume = {12}, number = {21}, pages = {}, doi = {10.3390/plants12213679}, pmid = {37960038}, issn = {2223-7747}, support = {8336//Interreg V-A Francia-Italia (ALCOTRA) (2014 - 2020) ALCOTRA ALCOTRA Progetto-Ponte "ANTES - Fiori eduli e piante aromatiche: attività capitalizzazione dei progetti ANTEA ed ESSICA"/ ; }, abstract = {The Salvia rosmarinus "Eretto Liguria" ecotype was studied as a source of valuable bioactive compounds. LC-MS analysis of the methanolic extract underlined the presence of diterpenoids, triterpenoids, polyphenolic acids, and flavonoids. The anti-virulence activity of carnosic acid along with the other most abundant compounds against methicillin-resistant Staphylococcus aureus (MRSA) was evaluated. Only carnosic acid induced a significant reduction in the expression of agrA and rnaIII genes, which encode the key components of quorum sensing (QS), an intracellular signaling mechanism controlling the virulence of MRSA. At a concentration of 0.05 mg/mL, carnosic acid inhibited biofilm formation by MRSA and the expression of genes involved in toxin production and made MRSA more susceptible to intracellular killing, with no toxic effects on eukaryotic cells. Carnosic acid did not affect biofilm formation by Pseudomonas aeruginosa, a human pathogen that often coexists with MRSA in complex infections. The selected ecotype showed a carnosic acid content of 94.3 ± 4.3 mg/g. In silico analysis highlighted that carnosic acid potentially interacts with the S. aureus AgrA response regulator. Our findings suggest that carnosic acid could be an anti-virulence agent against MRSA infections endowed with a species-specific activity useful in multi-microbial infections.}, } @article {pmid37958670, year = {2023}, author = {Franco, EM and Alves, LA and Naveed, H and Freitas, VAA and Bastos, DC and Mattos-Graner, RO}, title = {Amyloid Fibrils Produced by Streptococcus sanguinis Contribute to Biofilm Formation and Immune Evasion.}, journal = {International journal of molecular sciences}, volume = {24}, number = {21}, pages = {}, doi = {10.3390/ijms242115686}, pmid = {37958670}, issn = {1422-0067}, support = {2018/02054-4//São Paulo Research Foundation/ ; 2021/13074-9//São Paulo Research Foundation/ ; 2017/19899-4//São Paulo Research Foundation/ ; 2023/02087-8//São Paulo Research Foundation/ ; 2018/12248-9//São Paulo Research Foundation/ ; 303896/2022-1//National Council for Scientific and Technological Development/ ; 8887.352647/2019-0//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; Finance Code 001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Bacterial surface proteins assembled into amyloids contribute to biofilm formation and host immune evasion. Streptococcus sanguinis, a pioneer colonizer of teeth commonly involved in cardiovascular infections, expresses about thirty-three proteins anchored to the cell wall by sortase A. Here, we characterized the production of amyloid in S. sanguinis strains differing in biofilm and immune evasion phenotypes and investigated the role of sortase A in amyloidogenesis. Amyloid was identified in biofilms formed by nine strains, using Congo red (CR) staining and cross-polarized light microscopy. Additionally, EGCG, an amyloid inhibitor, impaired biofilm maturation in a strain-specific fashion. The amounts of amyloid-like components quantified in culture fluids of nine strains using thioflavin T and fluorimetry negatively correlated with bacterial binding to complement-activating proteins (SAP, C1q), C3b deposition and rates of opsonophagocytosis in PMNs, implying amyloid production in immune evasion. The deletion of the sortase A gene (srtA) in strain SK36 compromised amyloid production and sucrose-independent biofilm maturation. The srtA mutant further showed increased susceptibility to C3b deposition and altered interactions with PMNs as well as reduced persistence in human blood. These findings highlight the contribution of amyloids to biofilm formation and host immune evasion in S. sanguinis strains, further indicating the participation of sortase A substrates in amyloidogenesis.}, } @article {pmid37958634, year = {2023}, author = {Niu, L and Gao, M and Wen, S and Wang, F and Shangguan, H and Guo, Z and Zhang, R and Ge, J}, title = {Effects of Catecholamine Stress Hormones Norepinephrine and Epinephrine on Growth, Antimicrobial Susceptibility, Biofilm Formation, and Gene Expressions of Enterotoxigenic Escherichia coli.}, journal = {International journal of molecular sciences}, volume = {24}, number = {21}, pages = {}, doi = {10.3390/ijms242115646}, pmid = {37958634}, issn = {1422-0067}, support = {31672532//National Natural Science Foundation of China/ ; 202210224166//SIPT Project of Northeast Agricultural University/ ; S202210224168//SIPT Project of Northeast Agricultural University/ ; SKLVBF202214//the State Key Laboratory of Veterinary Biotechnology Foundation/ ; }, abstract = {Enterotoxigenic Escherichia coli (ETEC) is a significant contributor to diarrhea. To determine whether ETEC-catecholamine hormone interactions contribute to the development of diarrhea, we tested the effects of catecholamine hormones acting on ETEC in vitro. The results showed that in the presence of norepinephrine (NE) and epinephrine (Epi), the growth of 9 out of 10 ETEC isolates was promoted, the MICs of more than 60% of the isolates to 6 antibiotics significantly increased, and the biofilm formation ability of 10 ETEC isolates was also promoted. In addition, NE and Epi also significantly upregulated the expression of the virulence genes feaG, estA, estB, and elt. Transcriptome analysis revealed that the expression of 290 genes was affected by NE. These data demonstrated that catecholamine hormones may augment the diarrhea caused by ETEC.}, } @article {pmid37957573, year = {2023}, author = {Dutta, B and Halder, U and Chitikineni, A and Varshney, RK and Bandopadhyay, R}, title = {Delving into the lifestyle of Sundarban Wetland resident, biofilm producing, halotolerant Salinicoccus roseus: a comparative genomics-based intervention.}, journal = {BMC genomics}, volume = {24}, number = {1}, pages = {681}, pmid = {37957573}, issn = {1471-2164}, abstract = {BACKGROUND: Microbial community played an essential role in ecosystem processes, be it mangrove wetland or other intertidal ecologies. Several enzymatic activities like hydrolases are effective ecological indicators of soil microbial function. So far, little is known on halophilic bacterial contribution and function on a genomic viewpoint of Indian Sundarban Wetland. Considering the above mentioned issues, the aims of this study was to understand the life style, metabolic functionalities and genomic features of the isolated bacterium, Salinicoccus roseus strain RF1H. A comparative genome-based study of S. roseus has not been reported yet. Henceforth, we have considered the inclusion of the intra-species genome comparison of S. roseus to gain insight into the high degree of variation in the genome of strain RF1H among others.

RESULTS: Salinicoccus roseus strain RF1H is a pink-red pigmented, Gram-positive and non-motile cocci. The bacterium exhibited high salt tolerance (up to 15% NaCl), antibiotic resistance, biofilm formation and secretion of extracellular hydrolytic enzymes. The circular genome was approximately 2.62978 Mb in size, encoding 574 predicted genes with GC content 49.5%. Presence of genomic elements (prophages, transposable elements, CRISPR-Cas system) represented bacterial virulence and multidrug-resistance. Furthermore, genes associated with salt tolerance, temperature adaptation and DNA repair system were distributed in 17 genomic islands. Genes related to hydrocarbon degradation manifested metabolic capability of the bacterium for potential biotechnological applications. A comparative pangenome analysis revealed two-component response regulator, modified C4-dicarboxylate transport system and osmotic stress regulated ATP-binding proteins. Presence of genes encoding arginine decarboxylase (ADC) enzyme being involved in biofilm formation was reported from the genome. In silico study revealed the protein is thermostable and made up with ~ 415 amino acids, and hydrophilic in nature. Three motifs appeared to be evolutionary conserved in all Salinicoccus sequences.

CONCLUSION: The first report of whole genome analysis of Salinicoccus roseus strain RF1H provided information of metabolic functionalities, biofilm formation, resistance mechanism and adaptation strategies to thrive in climate-change induced vulnerable spot like Sundarban. Comparative genome analysis highlighted the unique genome content that contributed the strain's adaptability. The biomolecules produced during metabolism are important sources of compounds with potential beneficial applications in pharmaceuticals.}, } @article {pmid37956962, year = {2023}, author = {Musanna, and Faridoon Khan, U and Habib, G and Gul, H and Hayat, A and Ur Rehman, M}, title = {Contribution of the gyrA and waaG mutants to fluoroquinolones resistance, biofilm development, and persister cells formation in Salmonella enterica serovar Typhi.}, journal = {Gene}, volume = {}, number = {}, pages = {147943}, doi = {10.1016/j.gene.2023.147943}, pmid = {37956962}, issn = {1879-0038}, abstract = {Fluoroquinolone resistance in Salmonella has been reported worldwide and poses a serious public health threat in developing countries. Multiple factors contribute to fluoroquinolone resistance, including mutations in DNA gyrase and the acquisition of antimicrobial resistance genes. Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever in humans, which is highly prevalent in counties with poor sanitation and hygiene standards. Here, we reported S. Typhi clinical isolates that showed varying degrees of susceptibility to fluoroquinolones and were characterized by Analytical Profile Index 20E test kit and 16S rRNA sequencing. S. Typhi strain S27 was resistant to fluoroquinolones and had multiple mutations in the gyrA gene. The gyrA lies in the quinolone resistance determining region of S. Typhi and has mutations at codon 83 (Ser83Phe), codon 87 (Asp87Gly), codon 308 (Lys308Glu), and codon 328 (Val328Ile). S. Typhi strain S6 has no gyrA mutations and is sensitive to fluoroquinolones but forms a strong biofilm relative to S. Typhi S27. Transcriptional analysis of biofilm associated genes revealed that the waaG gene was significantly downregulated. The ΔwaaG mutant showed a significant decrease in persister cells and a strong biofilm formation relative to wild type and gyrA mutant. The gyrA tetra mutant persister assay revealed a significant increase in persister cells compared to wild type and ΔwaaG. Collectively, this is the first report of S. Typhi's two key genes and their roles in antibiotic tolerance, biofilm formation, and fluoroquinolone resistance that can help in understanding the mechanism of persister formation and eradication.}, } @article {pmid37956948, year = {2023}, author = {Saidulu, D and Agrawal, S and Bhatnagar, A and Gupta, AK}, title = {Sulfamethoxazole removal from wastewater via anoxic/oxic moving bed biofilm reactor: Degradation pathways and toxicity assessment.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129998}, doi = {10.1016/j.biortech.2023.129998}, pmid = {37956948}, issn = {1873-2976}, abstract = {The effects of sulfamethoxazole (SMZ), an antibiotic commonly detected in the water environment, on the performance of a single staged anoxic/oxic moving bed biofilm reactor (A/O MBBR), was investigated. The anoxic zone played a key role in the removal of SMZ with a percentage of contribution accounting for around 85% in the overall removal. Denitrifying heterotrophic microbes present in the anoxic zone showed relatively more resistance to higher SMZ loads. It was found that in extracellular polymeric substances, protein content was increased consistently with the increase in SMZ concentration. Based on the detected biotransformation products, four degradation pathways were proposed and the toxicity was evaluated. Metagenomic analysis revealed that at higher SMZ load the activity of genera, such as Proteobacteria and Actinobacteria was significantly affected. In summary, proper design and operation of staged A/O MBBR can offer a resilient and robust treatment towards SMZ removal from wastewater.}, } @article {pmid37956613, year = {2023}, author = {Zhao, Y and Chen, Z and Cai, Y and Xue, J and Zhang, L and Wang, L and Zhao, M and Zheng, Y and Xia, T and Yu, H and Jiang, T and Sun, Y}, title = {Aloe-emodin destroys the biofilm of Helicobacter pylori by targeting the outer membrane protein 6.}, journal = {Microbiological research}, volume = {278}, number = {}, pages = {127539}, doi = {10.1016/j.micres.2023.127539}, pmid = {37956613}, issn = {1618-0623}, abstract = {Biofilm formation is one of the most important factors causing drug resistance of Helicobacter pylori. Therefore, it is necessary to explore the mechanism underlying the biofilm formation and its eradication methods. The outer membrane proteins (OMPs) play important roles in the formation of bacterial biofilms and are considered the essential targets for new drug discovery. Natural products play significant roles in anti-bacterial and anti-biofilm functions. This study explored the key OMPs involved in the biofilm formation of H. pylori and the natural products that target these OMPs. Transcriptome sequencing, gene knockout, and electrophoretic mobility shift assay (EMSA) were performed to reveal that OMP6 was involved in the biofilm formation of H. pylori, which was regulated by non-phosphorylated ArsR. Molecular docking suggested that aloe-emodin (AE) could target OMP6 and destroy the biofilms of H. pylori. Further exploration of its mechanism found that AE could also inhibit the expression of omp6 mRNA by binding to its regulator ArsR. In summary, we have discovered a novel molecular mechanism regulating the biofilm formation of H. pylori and identified a natural product against H. pylori biofilms, providing potential clues for clinical treatment of H. pylori.}, } @article {pmid37956290, year = {2023}, author = {Prince, J and Jones, AD}, title = {Heterogenous biofilm mass-transport model replicates periphery sequestration of antibiotics in Pseudomonas aeruginosa PAO1 microcolonies.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {47}, pages = {e2312995120}, doi = {10.1073/pnas.2312995120}, pmid = {37956290}, issn = {1091-6490}, support = {R35 GM142898/GM/NIGMS NIH HHS/United States ; }, abstract = {A model for antibiotic accumulation in bacterial biofilm microcolonies utilizing heterogenous porosity and attachment site profiles replicated the periphery sequestration reported in prior experimental studies on Pseudomonas aeruginosa PAO1 biofilm cell clusters. These P. aeruginosa cell clusters are in vitro models of the chronic P. aeruginosa infections in cystic fibrosis patients which display recalcitrance to antibiotic treatments, leading to exacerbated morbidity and mortality. This resistance has been partially attributed to periphery sequestration, where antibiotics fail to penetrate biofilm cell clusters. The physical phenomena driving this periphery sequestration have not been definitively established. This paper introduces mathematical models to account for two proposed physical phenomena driving periphery sequestration: biofilm matrix attachment and volume-exclusion due to variable biofilm porosity. An antibiotic accumulation model which incorporated these phenomena better fit observed periphery sequestration data compared to previous models.}, } @article {pmid37956125, year = {2023}, author = {Angoshtari, R and Scribner, KT and Marsh, TL}, title = {The impact of primary colonizers on the community composition of river biofilm.}, journal = {PloS one}, volume = {18}, number = {11}, pages = {e0288040}, doi = {10.1371/journal.pone.0288040}, pmid = {37956125}, issn = {1932-6203}, abstract = {As a strategy for minimizing microbial infections in fish hatcheries, we have investigated how putatively probiotic bacterial populations influence biofilm formation. All surfaces that are exposed to the aquatic milieu develop a microbial community through the selective assembly of microbial populations into a surface-adhering biofilm. In the investigations reported herein, we describe laboratory experiments designed to determine how initial colonization of a surface by nonpathogenic isolates from sturgeon eggs influence the subsequent assembly of populations from a pelagic river community, into the existing biofilm. All eight of the tested strains altered the assembly of river biofilm in a strain-specific manner. Previously formed isolate biofilm was challenged with natural river populations and after 24 hours, two strains and two-isolate combinations proved highly resistant to invasion, comprising at least 80% of the biofilm community, four isolates were intermediate in resistance, accounting for at least 45% of the biofilm community and two isolates were reduced to 4% of the biofilm community. Founding biofilms of Serratia sp, and combinations of Brevundimonas sp.-Hydrogenophaga sp. and Brevundimonas sp.-Acidovorax sp. specifically blocked populations of Aeromonas and Flavobacterium, potential fish pathogens, from colonizing the biofilm. In addition, all isolate biofilms were effective at blocking invading populations of Arcobacter. Several strains, notably Deinococcus sp., recruited specific low-abundance river populations into the top 25 most abundant populations within biofilm. The experiments suggest that relatively simple measures can be used to control the assembly of biofilm on the eggs surface and perhaps offer protection from pathogens. In addition, the methodology provides a relatively rapid way to detect potentially strong ecological interactions between bacterial populations in the formation of biofilms.}, } @article {pmid37955766, year = {2023}, author = {Huang, Y and Han, Q and Zhou, J and Meng, X and Huo, L and Lei, Y}, title = {The effect of bovine trypsin on dental biofilm dispersion: an in vitro study.}, journal = {Odontology}, volume = {}, number = {}, pages = {}, pmid = {37955766}, issn = {1618-1255}, abstract = {To investigate the degradation effect of bovine trypsin on multispecies biofilm of caries-related bacteria and provide an experimental foundation for the prevention of dental caries. Standard strains of S. mutans, S. sanguis, S. gordonii, and L. acidophilus were co-cultured to form 24 h, 48 h, and 72 h biofilms. The experimental groups were treated with bovine trypsin for 30 s, 1 min, and 3 min. Morphological observation and quantitative analysis of extracellular polymeric substances (EPS), live bacteria, and dead bacteria were conducted using the confocal laser scanning microscope (CLSM). The morphological changes of EPS and bacteria were also observed using a scanning electron microscope (SEM). When biofilm was treated for 1 min, the minimal inhibitory concentration (MIC) of bovine trypsin to reduce EPS was 0.5 mg/mL in 24 h and 48 h biofilms, and the MIC of bovine trypsin was 2.5 mg/mL in 72 h biofilms (P < 0.05). When biofilm was treated for 3 min, the MIC of bovine trypsin to reduce EPS was 0.25 mg/mL in 24 h and 48 h biofilms, the MIC of bovine trypsin was 1 mg/mL in 72 h biofilm (P < 0.05). The ratio of live-to-dead bacteria in the treatment group was significantly lower than blank group in 24 h, 48 h, and 72 h multispecies biofilms (P < 0.05). Bovine trypsin can destroy multispecies biofilm structure, disperse biofilm and bacteria flora, and reduce the EPS and bacterial biomass in vitro, which are positively correlated with the application time and concentration.}, } @article {pmid37955583, year = {2023}, author = {Gu, W and Ren, Z and Han, J and Zhang, X and Zhu, B and Yan, Z and Xiao, H and Wei, Q}, title = {Design of biodegradable polyurethanes and post-modification with long alkyl chains via inhibiting biofilm formation and killing drug-resistant bacteria for the treatment of wound bacterial infection.}, journal = {Biomaterials science}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3bm01448g}, pmid = {37955583}, issn = {2047-4849}, abstract = {The development of cationic polymers that simulate antimicrobial peptides to treat bacterial infections has received much research interest. In order to obtain polymers that can not only eradicate bacteria but also inhibit biofilm formation, without inducing bacterial drug resistance, a series of cationic polymers have been developed. Despite recent progress, the chemical structures of these polymers are stable, making them recalcitrant to biodegradation and metabolism within organisms, potentially inducing long-term toxicity. To overcome this limitation, herein, a novel strategy of designing biodegradable polyurethanes with tertiary amines and quaternary ammonium salts via condensation polymerization and post-functionalizing them is reported. These polymers were found to exhibit potent antibacterial activity against Staphylococcus aureus and Escherichia coli, effectively prevent the formation of Staphylococcus aureus biofilms, act quickly and effectively against bacteria and display no resistance after repeated use. In addition, the potent in vivo antibacterial effects of these antimicrobial polyurethanes in a mouse model with methicillin-resistant Staphylococcus aureus skin infection are demonstrated.}, } @article {pmid37954509, year = {2023}, author = {Zhou, Y and Liu, MJ and Liao, XY and Chen, YT and Liao, QX and Lin, JD and Lin, HR and Huang, YH}, title = {New Attempts to Inhibit Methicillin-Resistant Staphylococcus aureus Biofilm? A Combination of Daptomycin and Azithromycin.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {7029-7040}, pmid = {37954509}, issn = {1178-6973}, abstract = {OBJECTIVE: To investigate the antibacterial impact of daptomycin and azithromycin in vitro on methicillin-resistant Staphylococcus aureus (MRSA) biofilm.

METHODS: (1) Measure the strain growth curve and the biofilm formation curve. (2) Determine the minimum inhibitory concentrations (MICs) of daptomycin and azithromycin. (3) Investigate the antibacterial impact of the combination of daptomycin and azithromycin. (4) Perform the evaluation of the intervention impact of antimicrobial agents on MRSA biofilm. (5) Observe the biofilm after intervention with the antibacterial agent.

RESULTS: (1) MRSA exhibited three phases: lag phase (0-4 h), logarithmic growth (4-8 h) and stationary phase after 18 h; its biofilm began to form at 6 h, semi-matured at 24 h, and reached maturity after 48 h. (2) The MICs of daptomycin and azithromycin were 8 μg/mL and greater than 256 μg/mL, respectively. (3) The combination of daptomycin and azithromycin has an additive effect on MRSA (Fractional Inhibitory Concentration Index [FICI] 0.625) (FICI = MIC of drug A in combination/MIC of drug A alone + MIC of drug B in combination/MIC of drug B alone). Evaluation criteria: Synergistic effect is considered when FICI ≤ 0.5; additive effect is considered when 0.5 < FICI ≤ 1; irrelevant effect is considered when 1 < FICI ≤ 2; antagonistic effect is considered when FICI > 2). (4) Daptomycin or azithromycin at MICs inhibited not only the growth of planktonic bacteria but also the formation of biofilm. (5) The combination of both, in which group the ratio of live/dead bacteria is low and the biofilm morphology was incomplete, was more productive than monotherapy in against biofilm.

CONCLUSION: Both daptomycin and azithromycin have anti-MRSA biofilm activity, and daptomycin is dominant. The fact that the combination of both can significantly inhibit the further maturation of MRSA biofilm and destroy already formed biofilm demonstrates the superiority of the combination over the monotherapy.}, } @article {pmid37953580, year = {2023}, author = {Liang, J and Lin, S and He, L}, title = {Formation ability and drug resistance mechanism of Klebsiella pneumoniae biofilm and capsule for multidrug-resistant.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {10}, pages = {88-93}, doi = {10.14715/cmb/2023.69.10.12}, pmid = {37953580}, issn = {1165-158X}, abstract = {This study was to explore the formation ability of biofilm and capsule and the drug resistance mechanism for multidrug-resistant Klebsiella pneumoniae. firstly, 55 strains of K. pneumoniae were screened out from the body fluid specimens of the laboratory. The strains were drug-resistant, and the characteristics of clinical infections of these strains were analyzed. Secondly, all strains were tested for the presence of biofilms and capsules, and then the deoxyribonucleic acid (DNA) genomes of the strains extracted were detected using polymerase chain reaction (PCR) technology. Finally, the serotype genes and virulence genes of the strains were screened, and the relationship between these two genes and the formation of capsules and biofilms was analyzed and compared. A new generation of sequencing technology was applied to analyze the genome structure of K. pneumoniae, comparative genomics technology was adopted to analyze the drug resistance plasmids, and molecular cloning and other methods were utilized to clone the drug resistance-related genes. of the 55 strains of K. pneumoniae isolated clinically, 61.8% came from blood with a total number of 34 strains; 8 strains were from secretion specimens (accounting for 14.5% of the total); and 7 strains were from drainage fluid (accounting for 12.7% of the total), including 2 strains from pus, bile, and pleural fluid, respectively. The strains were tested by PCR, of which iroN virulence genes were the most (34 strains), accounting for 61.8%, followed by wabG and fimH (33 strains, accounting for 60% of the total), followed by magA, K2, K20, K1, and K57. The positive rates of the two virulence genes (fimH and wabG) were higher in positive strains of biofilm. The drug susceptibility results showed that ampicillin and amoxicillin were more resistant to capsule-positive strains than the capsule-negative strains. K. pneumoniae had been able to form a complete capsule and biofilm, the formation rate of biofilm was higher than that of the capsule, and there was an increasing trend. The two serotype genes (K20 and K2) accounted for relatively high proportions, and K. pneumoniae carried relatively more virulence genes (wabG and fimH), which may be closely related to the capsule production of K. pneumoniae. In addition, resistance-related genes were also transferred horizontally in different strains of bacteria, forming a wide range of drug resistance, which brought great difficulties to clinical work.}, } @article {pmid37951751, year = {2023}, author = {Wang, S and Fang, L and Zhou, H and Wang, M and Zheng, H and Wang, Y and Weir, MD and Masri, R and Oates, TW and Cheng, L and Xu, HHK and Liu, F}, title = {Silica nanoparticles containing nano-silver and chlorhexidine respond to pH to suppress biofilm acids and modulate biofilms toward a non-cariogenic composition.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.dental.2023.11.006}, pmid = {37951751}, issn = {1879-0097}, abstract = {OBJECTIVES: Dental caries is caused by acids from biofilms. pH-sensitive nanoparticle carriers could achieve improved targeted effectiveness. The objectives of this study were to develop novel mesoporous silica nanoparticles carrying nanosilver and chlorhexidine (nMS-nAg-Chx), and investigate the inhibition of biofilms as well as the modulation of biofilm to suppress acidogenic and promote benign species for the first time.

METHODS: nMS-nAg was synthesized via a modified sol-gel method. Carboxylate group functionalized nMS-nAg (COOH-nMS-nAg) was prepared and Chx was added via electrostatic interaction. Minimal inhibitory concentration (MIC), inhibition zone, and growth curves were evaluated. Streptococcus mutans (S. mutans), Streptococcus gordonii (S. gordonii), and Streptococcus sanguinis (S. sanguinis) formed multispecies biofilms. Metabolic activity, biofilm lactic acid, exopolysaccharides (EPS), and TaqMan real-time polymerase chain reaction (RT-PCR) were tested. Biofilm structures and biomass were observed by scanning electron microscopy (SEM) and live/dead bacteria staining.

RESULTS: nMS-nAg-Chx possessed pH-responsive properties, where Chx release increased at lower pH. nMS-nAg-Chx showed good biocompatibility. nMS-nAg-Chx exhibited a strong antibacterial function, reducing biofilm metabolic activity and lactic acid as compared to control (p < 0.05, n = 6). Moreso, biofilm biomass was dramatically suppressed in nMS-nAg-Chx groups. In control group, there was an increasing trend of S. mutans proportion in the multispecies biofilm, with S. mutans reaching 89.1% at 72 h. In sharp contrast, in nMS-nAg-Chx group of 25 μg/mL, the ratio of S. mutans dropped to 43.7% and the proportion of S. gordonii and S. sanguinis increased from 19.8% and 10.9 to 69.8% and 56.3%, correspondingly.

CONCLUSION: pH-sensitive nMS-nAg-Chx had potent antibacterial effects and modulated biofilm toward a non-cariogenic tendency, decreasing the cariogenic species nearly halved and increasing the benign species approximately twofold. nMS-nAg-Chx is promising for applications in mouth rinse and endodontic irrigants, and as fillers in resins to prevent caries.}, } @article {pmid37951730, year = {2023}, author = {Mehdipour, M and Gholipour, S and Mohammadi, F and Hatamzadeh, M and Nikaeen, M}, title = {Incidence of co-resistance to antibiotics and chlorine in bacterial biofilm of hospital water systems: Insights into the risk of nosocomial infections.}, journal = {Journal of infection and public health}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jiph.2023.10.032}, pmid = {37951730}, issn = {1876-035X}, abstract = {The presence of biofilms in drinking water distribution systems (DWDS) in healthcare settings poses a considerable risk to the biological security of water, particularly when the biofilm bacteria demonstrate antimicrobial resistance characteristics. This study aimed to investigate the occurrence of antibiotic-resistant bacteria (ARB) in biofilms within DWDS of hospitals. The chlorine resistance of the isolated ARB was analyzed, and then chlorine-resistant bacteria (CRB) were identified using molecular methods. Additionally, the presence of several antibiotic resistance genes (ARGs) was monitored in the isolated ARB. Out of the 41 biofilm samples collected from hospitals, ARB were detected in 32 (78%) of the samples. A total of 109 colonies of ARB were isolated from DWDS of hospitals, with β-lactam resistant bacteria, including ceftazidime-resistant and ampicillin-resistant bacteria, being the most frequently isolated ARB. Analyzing of ARGs revealed the highest detection of aac6, followed by sul1 gene. However, the β-lactamase genes blaCTX-M and blaTEM were not identified in the ARB, suggesting the presence of other β-lactamase genes not included in the tested panel. Exposure of ARB to free chlorine at a concentration of 0.5 mg/l showed that 64% of the isolates were CRB. However, increasing the chlorine concentration to 4 mg/l decreased the high fraction of ARB (91%). The domi‌‌nant CRB identified were Sphingomonas, Brevundimonas, Stenotrophomonas, Bacillus and Staphylococcus with Bacillus exhibiting the highest frequency. The results highlight the potential risk of biofilm formation in the DWDS of hospitals, leading to the dissemination of ARB in hospital environments, which is a great concern for the health of hospitalized patients, especially vulnerable individuals. Surveillance of antimicrobial resistance in DWDS of hospitals can provide valuable insights for shaping antimicrobial use policies and practices that ensure their efficacy.}, } @article {pmid37951378, year = {2023}, author = {Qin, W and Xiao, Q and Hong, M and Yang, J and Song, Y and Ma, J}, title = {Nano manganese dioxide coupling carbon source preloading granular activated carbon biofilter enhancing biofilm formation and pollutant removal.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117606}, doi = {10.1016/j.envres.2023.117606}, pmid = {37951378}, issn = {1096-0953}, abstract = {The formation of stable and mature biofilms affects the efficient and stable removal of ammonium by biological activated carbon (BAC). In this study, the new granular activated carbon (GAC) was preloaded with the carbon source (glucose and sucrose) and nano manganese dioxide (nMnO2) before using. Then tests were performed to determine whether substrate preloading promoted ammonium removal. The ammonium removal treated by nMnO2 coupled with sucrose-loaded BAC reached 49.1 ± 2.5%, which was 1.7 times higher than that by the nonloaded BAC 28.2 ± 1.9%). The biomass on the substrate-loaded BAC reached 5.83 × 10[6]-1.22 × 10[7] cells/g DW GAC on Day 7, which was 4.6-9.5 times higher than the value of the nonloaded BAC (1.28 × 10[6] cells/g DW GAC). The amount of extracellular polymer (i.e., protein) on nMnO2 coupled to sucrose-loaded BAC was promoted significantly. Flavobacterium (0.7%-11%), Burkholderiaceae (13%-20%) and Aquabacterium (30%-67%) were the dominant functional bacteria on the substrate-loaded BAC, which were conducive to the nitrification or denitrification process. The results indicated that loading nMnO2 and/or a carbon source accelerated the formation of biofilms on BAC and ammonium removal. Additionally, the ammonium removal treated by nMnO2 coupled with sucrose-loaded BAC was contributed by microbial degradation (56.0 ± 2.5%), biofilm adsorption (38.7 ± 2.1%) and GAC adsorption (5.3 ± 0.3%), suggesting a major role of microbial degradation.}, } @article {pmid37951291, year = {2023}, author = {Dini, C and Costa, RC and Bertolini, M and Shibli, JA and Feres, M and Inêz Klein, M and de Avila, ÉD and Souza, JGS and Barão, VAR}, title = {In vitro polymicrobial oral biofilm model represents clinical microbial profile and disease progression during implant-related infections.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad265}, pmid = {37951291}, issn = {1365-2672}, abstract = {AIM: Clinically relevant in vitro biofilm models are essential and valuable tools for mechanistically dissecting the etiopathogenesis of infectious diseases and test new antimicrobial therapies. Thus, the aim of this study was to develop and test a clinically relevant in vitro oral polymicrobial biofilm model that mimics implant-related infections in terms of microbial profile.

METHODS AND RESULTS: For this purpose, 24-well plate system was used to model oral biofilms, using three different microbial inoculums to grow in vitro biofilms: (#1) human saliva from periodontally healthy patients; (#2) saliva as in inoculum #1 + Porphyromonas gingivalis strain; (#3) supra and subgingival biofilm collected from peri-implant sites of patients diagnosed with peri-implantitis. Biofilms were grown to represent the dynamic transition from an aerobic to anaerobic community profile. Subsequently, biofilms were collected after each phase and evaluated for microbiological composition, microbial counts, biofilm biomass, structure, and susceptibility to chlorhexidine (CHX). Results showed higher live cell count (p<.05) for biofilms developed from patients' biofilm inoculum, but biomass volume, dry weight, and microbiological composition were similar among groups (p>.05). Interestingly, according to the checkerboard DNA-DNA hybridization results, the biofilm developed from stimulated human saliva exhibited a microbial composition more similar to the clinical subgingival biofilm of patients with peri-implantitis, with proportions of the main pathogens closer to those found in the disease. In addition, biofilm developed using saliva as inoculum was shown to be susceptible to CHX with significant reduction in bacteria compared with biofilms without exposure to CHX (p<.05).

CONCLUSION: The findings suggested that the in vitro polymicrobial biofilm developed from human saliva as inoculum is a suitable model and clinically relevant tool for mimicking the microbial composition of implant-related infections.}, } @article {pmid37949404, year = {2023}, author = {Yuan, L and Zhang, Y and Mi, Z and Zheng, X and Wang, S and Li, H and Yang, Z}, title = {Calcium-mediated modulation of Pseudomonas fluorescens biofilm formation.}, journal = {Journal of dairy science}, volume = {}, number = {}, pages = {}, doi = {10.3168/jds.2023-23860}, pmid = {37949404}, issn = {1525-3198}, abstract = {Biofilm formation is usually affected by many environmental factors including divalent cations. The purpose of the current work was to analyze how calcium (Ca[2+]) affects the biofilm formation of dairy Pseudomonas fluorescens isolates by investigating their growth, swarming motility, biofilm-forming capacity, EPS production, and biofilm structures. Moreover, the regulation mechanism of Ca[2+] involved in its biofilm formation was explored through RNA-sequencing analysis. This work revealed that supplementation of 5, 10, 15, and 20 mM Ca[2+] significantly reduced the swarming motility of P. fluorescens strains (P.F2, P.F4, and P.F17), but the biofilm-forming ability and polysaccharide production were increased after the supplementation of 5 and 10 mM Ca[2+]. By the supplementation of Ca[2+], complex structures with more cell clusters glued together in P. fluorescens P.F4 biofilms were confirmed by scanning electron microscopy, and increased biomass and coverage of P. fluorescens P.F4 biofilms were observed by confocal laser scanning microscopy. In addition, RNA-sequencing results showed that P. fluorescens P.F4 showed a transcriptional response to the supplementation of 10 mM Ca[2+], and a total of 137 genes were significantly expressed. The differential genes were represented in 4 upregulated KEGG pathways (nonribosomal peptide structures, quorum sensing, biosynthesis of siderophore group nonribosomal peptides, and phenylalanine metabolism), and 4 downregulated KEGG pathways (flagellar assembly, amino sugar and nucleotide sugar metabolism, nitrotoluene degradation, and cationic antimicrobial peptide (CAMP) resistance). The results indicate that Ca[2+] might serve as an enhancer to substantially trigger the biofilm formation of dairy P. fluorescens isolates in the dairy industry.}, } @article {pmid37949290, year = {2023}, author = {Pratap, V and Kumar, R and Kumar, S and Yadav, BR}, title = {Optimization of moving bed biofilm reactors for the treatment of municipal wastewater.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117560}, doi = {10.1016/j.envres.2023.117560}, pmid = {37949290}, issn = {1096-0953}, abstract = {The properties of biocarriers significantly influence the performance of a moving bed-biofilm reactor (MBBR). This study aimed to assess the impact of media type, filling ratio, and hydraulic retention time (HRT) on biofilm formation and MBBR performance in both batch and continuous setups using real municipal wastewater. Two different media, high-density polyethylene (HDPE) and polypropylene (PPE), with varying surface area and properties were used. Biofilm growth and MBBR performance were monitored and optimized using response surface methodology. The effect of different media was investigated for three filling ratios of 20%, 40% and 60% and HRT of 4, 6 and 8 h. Results depicted a better biofilm growth on HDPE media in comparison to PPE carriers due to difference in media structure and surface properties. At all the conditions tested, HDPE media showed comparatively better performance for the removal of organic matter and nutrients than PPE media. The maximum organic matter removal efficiency was found as 77% and 75% at an HRT of 6 h and filling ratio of 40% for HDPE and PPE media, respectively. The ammonia removal was also found better for HDPE media due to its geometry and structure favoring the anoxic conditions with maximum removal of 89% achieved at 6-h HRT and 40% filling ratio. Overall, the system with HDPE media indicated more stability in terms of reactor performance than PPE carriers with variations in the operating conditions.}, } @article {pmid37947038, year = {2023}, author = {Leelapornpisid, W and Wanwatanakul, P and Mahatnirunkul, T}, title = {Efficacy of calcium hydroxide-loaded poly(lactic-co-glycolic acid) biodegradable nanoparticles as an intracanal medicament against endodontopathogenic microorganisms in a multi-species biofilm model.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {}, number = {}, pages = {}, doi = {10.1111/aej.12812}, pmid = {37947038}, issn = {1747-4477}, abstract = {This study aimed to evaluate the antimicrobial activity of calcium hydroxide-loaded poly(lactic-co-glycolic acid) nanoparticles (CH-loaded PLGA NPs) on multi-species biofilms. Human root blocks were prepared (n = 40), and multi-species suspensions of Candida albicans, Enterococcus faecalis and Streptococcus gordonii were incubated within the root canals for 21 days. Canals (n = 10/group) were then medicated with saline solution (negative control), chlorhexidine (positive control), calcium hydroxide and CH-loaded PLGA NPs for 7 days. Samples taken from the 0.1 mm root canal dentin were collected, and cell growth was detected by culture on BHI agar. The viable cell count of the Ca(OH)2 , chlorhexidine gel and CH-loaded PLGA NPs group was significantly lower than the normal saline group (p < 0.001). CH-loaded PLGA NPs demonstrated a significant lower viable cell than Ca(OH)2 (p < 0.001); it has potential as a medicament for endodontic therapy.}, } @article {pmid37945115, year = {2023}, author = {Singh, P and Srivastava, S and Malhotra, R and Mathur, P}, title = {Identification of Candida auris by PCR and assessment of biofilm formation by crystal violet assay.}, journal = {Indian journal of medical microbiology}, volume = {46}, number = {}, pages = {100421}, doi = {10.1016/j.ijmmb.2023.100421}, pmid = {37945115}, issn = {1998-3646}, abstract = {INTRODUCTION: Candida auris is a notorious pathogen capable of forming biofilms on devices as well as host tissues, often culminating in infections. We evaluated characteristics of infections and the methods to diagnose C. auris over a period of three years in a tertiary care hospital.

METHODS: Patients admitted between 2018 and 2020, who had candidemia due to C. auris were included in the study. Identification was performed using HiCrome™ Candida Differential Agar, Vitek 2 (BioMérieux, Inc., Marcy-l'Etoile, France) and MALDI-TOF, Vitek-MS. Identification was confirmed by detection of rDNA region covering part of 5.8S, entire of ITS2, and part of 28S by polymerase chain reaction (PCR). Biofilm formation was assessed by crystal violet staining.

RESULTS: Presence of central line and broad spectrum antimicrobials were noted in all patients whereas total parenteral nutrition was given in 82.1% of these patients. Identification by Vitek2 v8.1 correlated with MALDI-TOF MS. PCR products of length 163 ​bp were obtained in all isolates as visualized by agarose gel electrophoresis. The biofilm quantity measured as A560 of the twenty-eight C. auris isolates ranged from 0.16 to 0.80 compared to C. albicans.

CONCLUSIONS: C. auris can be identified by PCR targeting specific rDNA region. Biofilm formation and quantification can be achieved by growing C. auris isolates in Mueller-Hinton broth over a duration of 48 ​h.}, } @article {pmid37944993, year = {2023}, author = {Chen, L and Peng, M and Li, H and Zhou, J and He, W and Hu, R and Ye, F and Li, Y and Shi, L and Liu, Y}, title = {Metal-Phenolic Network with Pd Nanoparticle Nodes Synergizes Oxidase-Like And Photothermal Properties to Eradicate Oral Polymicrobial Biofilm-Associated Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2306376}, doi = {10.1002/adma.202306376}, pmid = {37944993}, issn = {1521-4095}, abstract = {Designing an effective treatment strategy to combat oral diseases caused by complex polymicrobial biofilms remains a great challenge. Herein, we construct a series of metal-phenolic network with Pd nanoparticle nodes (MPN-Pd) using polyphenols as stabilizers and reducing agents. Among them, sulfonated lignin-Pd (SLS-Pd) with ultrafine size palladium nanoparticles (Pd NPs) and broadband near infrared absorption exhibited excellent oxidase-like activity and stable photothermal effect. In vitro experiments demonstrate that the superoxide radical generated by SLS-Pd oxidase-like activity exhibits selective antibacterial effects, while its photothermal effect induced hyperthermia exhibits potent antifungal properties. This difference is further elucidated by RNA-sequencing analysis and all-atom simulation. Moreover, the SLS-Pd-mediated synergistic antimicrobial system exhibits remarkable efficacy in combating various biofilms and polymicrobial biofilms. By establishing a root canal model and an oropharyngeal candidiasis model, the feasibility of the synergistic antimicrobial system in treating oral biofilm-related infections is further validated. This system provides a promising therapeutic approach for polymicrobial biofilm-associated infections in the oral cavity. This article is protected by copyright. All rights reserved.}, } @article {pmid37944893, year = {2023}, author = {Shrestha, S and Bista, S and Byanjankar, N and Prasai Joshi, T}, title = {Evaluation of bottled drinking water and occurrence of multidrug-resistance and biofilm producing bacteria in Nepal.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122896}, doi = {10.1016/j.envpol.2023.122896}, pmid = {37944893}, issn = {1873-6424}, abstract = {Health consequences arising from unsafe drinking water and water insecurity leads to increased reliance on useage of bottled water. Biofilm producing antibiotic resistant bacteria in bottled water may pose a risk to public health. This study aims to assess the quality of bottled drinking water with a focus on biofilm producing and drug resistant coliform. We analyzed 60 bottled water samples of 30 different brands purchased from Kathmandu for physicochemical and microbial analysis. The parameters pH, iron, total coliform count, Escherichia coli count, and fecal coliform count exceeded National Drinking Water Quality Standards, 2022 in 30.00%, 16.67%, 66.67%, 23.33%, and 16.67% of samples, respectively. Water quality index measurement showed 36.67% and 6.67% of bottled water samples were categorized as grade A and grade B indicating excellent and good water quality, respectively. However, 56.67% of bottled water samples fall under grade E meaning unsuitable for drinking. Among 14 coliform isolates, 85.71% and 14.29% were identified as E. coli and Klebsiella spp, respectively. The antibiotic susceptibility testing revealed that 28.57% of the isolates were multidrug-resistant and Gentamicin resistant isolates comprised 71.43%. However, none of the isolates were carbapenem (meropenem) resistant. In this study, 42.87% of the isolates were found biofilm producers with 14.29% each of strong, moderate, and weak biofilm producers. The genetic potential of biofilm producing capacity of the isolates was assessed by Polymerase Chain Reaction (PCR) amplification of bcsA and csgD genes. Our results showed that 66.67% and 50.00% of the isolates harbored bcsA and csgD genes, respectively. This study highlights potential public health hazards associated with consumption of bottled water containing biofilm producing drug resistant bacteria in Nepal.}, } @article {pmid37944719, year = {2023}, author = {Behera, M and Singh, G and Vats, A and Parmanand, and Roshan, M and Gautam, D and Rana, C and Kesharwani, RK and De, S and Ghorai, SM}, title = {Expression and characterization of novel chimeric endolysin CHAPk-SH3bk against biofilm-forming methicillin-resistant Staphylococcus aureus.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127969}, doi = {10.1016/j.ijbiomac.2023.127969}, pmid = {37944719}, issn = {1879-0003}, abstract = {The continuous evolution of antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) due to the misuse of antibiotics lays out the need for the development of new antimicrobials with higher activity and lower resistance. In this study, we have expressed novel chimeric endolysin CHAPk-SH3bk derived from LysK to investigate its antibacterial activity against planktonic and biofilm-forming MRSA. The molecular docking and MD simulation results identified critical amino acids (ASP47, ASP56, ARG71, and Gly74) of CHAPk domain responsible for its catalytic activity. Chimeric endolysin CHAPk-SH3bk showed an effective binding to peptidoglycan fragment using 14 hydrogen bonds. The in-vitro antibacterial assays displayed higher activity of CHAPk against planktonic MRSA with 2-log10 reduction in 2 h. Both CHAPk and CHAPk-SH3bk displayed bactericidal activity against MRSA with ~4log10 and ~3.5log10 reduction in 24 h. Biofilm reduction activity displayed CHAPk-SH3bk reduced 33 % and 60 % of hospital-associated ATCC®BAA-44™ and bovine origin SA1 respectively. The CHAPk treatment reduced 47 % of the preformed biofilm formed by bovine-origin MRSA SA1. This study indicates an effective reduction of preformed MRSA biofilms of human and animal origin using novel chimeric construct CHAPk-SH3bk. Stating that the combination and shuffling of different domains of phage endolysin potentially increase its bacteriolytic effectiveness against MRSA.}, } @article {pmid37944355, year = {2023}, author = {Godain, A and Vogel, TM and Fongarland, P and Haddour, N}, title = {Influence of shear stress on electroactive biofilm characteristics and performance in microbial fuel cells.}, journal = {Biosensors & bioelectronics}, volume = {244}, number = {}, pages = {115806}, doi = {10.1016/j.bios.2023.115806}, pmid = {37944355}, issn = {1873-4235}, abstract = {This study has provided comprehensive insights into the intricate relationship between shear stress and the development, structure, and functionality of electroactive biofilms in Microbial Fuel Cells (MFCs). A multichannel microfluidic MFC reactors that created specific shear stress on the anode, were designed for the simultaneous study of multiple flow conditions using the same medium. Then, the evolution of the biofilm growth under different shear stress conditions (1, 5 and 10 mPa) were compared. The taxonomic and functional structure was studied by 16S rRNA gene and metagenomic sequencing and the physical biofilm characteristics were measured via fluorescence microscopy. The results demonstrate the pivotal role of shear stress in influencing the growth kinetics, electrical performance, and physical structure of anodic biofilms. Notably, the selection of specific EAB was observed to be shear stress-dependent, with a marked increase in specific EAB abundance as shear stress increased. The power density, while not directly correlated with the relative abundance of specific or nonspecific EAB, exhibited a strong linear relationship with biofilm coverage. This suggests that factors beyond the microbial composition, potentially including mass transport or electrochemical conditions, might be instrumental in determining electricity production. The functional metagenomic analysis further highlighted the complexities of extracellular electron transfer (EET) mechanisms in electroactive biofilm. While certain genes associated with EET in known species such as Geobacter and Shewanella were identified, the study also examined the limitations of solely relying on genetic markers to infer EET capabilities, emphasizing the need for complementary metaproteomic analyses. This study demonstrates the multifaceted impact of shear stress on electroactive biofilm and paves the way for future investigations aimed at harnessing the potential of electroactive biofilms in microbial fuel cell applications.}, } @article {pmid37944020, year = {2023}, author = {Zhang, Y and Han, Y and Huang, Z and Huang, Y and Kong, J and Sun, Y and Cao, J and Zhou, T}, title = {Restoring Colistin Sensitivity and Combating Biofilm Formation: Synergistic Effects of Colistin and Usnic Acid against Colistin-Resistant Enterobacteriaceae.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00315}, pmid = {37944020}, issn = {2373-8227}, abstract = {Colistin (COL), the last line of defense in clinical medicine, is an important therapeutic option against multidrug-resistant Gram-negative bacteria. In this context, the emergence of colistin-resistant (COL-R) bacteria mediated by broad-spectrum efflux pumps, mobile genetic elements, and biofilm formation poses a significant public health concern. In response to this challenge, a novel approach of combining COL with usnic acid (UA) has been proposed in this study. UA is a secondary metabolite derived from lichens and is well-known for its anti-inflammatory properties. This study aimed to investigate the synergistic effects of UA and COL against COL-R Enterobacteriaceae both in vitro and in vivo. The exceptional synergistic antibacterial activity exhibited by the combination of COL and UA was demonstrated by performing a comprehensive set of assays, including the checkerboard assay, time-dependent killing assay, and Live/Dead bacterial cell viability assay. Furthermore, crystal violet staining and scanning electron microscopy assays revealed the inhibitory effect of this combination on the biofilm formation. Mechanistically, the combination of UA and COL exacerbated cell membrane rupture, induced DNA damage, and generated a significant amount of reactive oxygen species, which ultimately resulted in bacterial cell death. In addition, erythrocyte hemolysis and cell viability tests confirmed the biocompatibility of the combination. The evaluation of the COL/UA combination in vivo using Galleria mellonella larvae and a mouse infection model showed a significant improvement in the survival rate of the infected larvae as well as a reduction in the bacterial load in the mouse thigh muscle. These findings, for the first time, provide strong evidence for the potential application of COL/UA as an effective alternative therapeutic option to combat infections caused by COL-R Enterobacteriaceae strains.}, } @article {pmid37941882, year = {2023}, author = {Mohamed, NA and Alrawy, MH and Makbol, RM and Mohamed, AM and Hemdan, SB and Shafik, NS}, title = {Type VI secretion system (T6SS) in Klebsiella pneumoniae, relation to antibiotic resistance and biofilm formation.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {5}, pages = {601-608}, pmid = {37941882}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The type VI secretion system (T6SS) was identified as a novel virulence factor in many Gram-negative bacteria. This study aimed to investigate the frequency of the T6SS genes in Klebsiella pneumoniae-causing different nosocomial infections, and to study the association between T6SS, antibiotic resistance, and biofilm formation in the isolated bacteria.

MATERIALS AND METHODS: A total of fifty-six non-repetitive K. pneumoniae isolates were collected from different inpatients admitted at Sohag University Hospital from September 2022 to March 2023. Samples were cultured, colonies were identified, and antimicrobial sensitivity was done by VITEK® 2 Compact. Biofilm formation was checked using Congo red agar method. T6SS genes, and capsular serotypes were detected by PCR.

RESULTS: Fifty-six K. pneumoniae isolates were obtained in culture. 38 isolates (67.86%) produced biofilm and 44 (78.57%) were positive for T6SS in PCR. There was a significant association between the presence of T6SS and resistance to the following antibiotics: meropenem, ciprofloxacin, and levofloxacin. All biofilm-forming bacteria had T6SS, with significant differences towards T6SS -positive bacteria. There was no significant association between T6SS, and the presence of certain capsular types.

CONCLUSION: The T6SS-positive K. pneumoniae has greater antibiotic resistance, and biofilm-forming ability which is considered a potential pathogenicity of this emerging gene cluster.}, } @article {pmid37941876, year = {2023}, author = {Khaltabadi Farahani, R and Ebrahimi-Rad, M and Shahrokhi, N and Khaltabadi Farahani, AH and Ghafouri, SA and Rezaei, M and Gharibzadeh, S and Ghalyanchi Langeroudi, A and Ehsani, P}, title = {High prevalence of antibiotic resistance and biofilm formation in Salmonella Gallinarum.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {5}, pages = {631-641}, pmid = {37941876}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Antibiotic resistance is an indicator of the passively acquired and circulating resistance genes. Salmonella Gallinarum significantly affects the poultry food industry. The present study is the first study of the S. Gallinarum biofilm in Iran, which is focused on the characterization of the S. Gallinarum serovars and their acquired antibiotic resistance genes circulating in poultry fields in central and northwestern Iran.

MATERIALS AND METHODS: Sixty isolates of S. Gallinarum serovar were collected from feces of live poultry. The bacteria were isolated using biochemical tests and confirmed by Multiplex PCR. Biofilm formation ability and the antibacterial resistance were evaluated using both phenotypic and genotypic methods. The data were analyzed using SPSS software.

RESULTS: According to Multiplex PCR for ratA, SteB, and rhs genes, all 60 S. Gallinarum serovars were Gallinarum biovars. In our study, the antibiotic resistance rate among isolated strains was as follows: Penicillin (100%), nitrofurantoin (80%), nalidixic acid (45%), cefoxitin (35%), neomycin sulfate (30%), chloramphenicol (20%), and ciprofloxacin (5%). All isolates were susceptible to imipenem, ertapenem, ceftriaxone, ceftazidime, and ceftazidime+clavulanic acid. All sixty isolates did not express the resistance genes IMP, VIM, NDM, DHA, blaOXA48, and qnrA. On the other hand, they expressed GES (85%), qnrB (75%), Fox M (70%), SHV (60%), CITM (20%), KPC (15%), FOX (10%), MOXM (5%), and qnrS (5%). All S. Gallinarum isolates formed biofilm and expressed sdiA gene.

CONCLUSION: Considering that the presence of this bacteria is equal to the death penalty to the herd, the distribution of resistance genes could be a critical alarm for pathogen monitoring programs in the region. This study showed a positive correlation between biofilm formation and 50% of tested resistance genes. Also, it was found that the most common circulating S. gallinarum biovars are multidrug-resistant.}, } @article {pmid37941805, year = {2023}, author = {Haas, B and James, S and Parker, AE and Gagnon, MC and Goulet, N and Labrie, P}, title = {Comparison of quantification methods for an endoscope lumen biofilm model.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100163}, pmid = {37941805}, issn = {2590-2075}, abstract = {Biofilm has been implicated in multi-drug resistant organism outbreaks following endoscopic procedures. Automated Endoscope Reprocessors (AER) are devices validated to clean and disinfect endoscopes per applicable standards. The ISO 15883 part 4 standard guides performance testing validation of AERs, including cleaning performance using a biofilm test soil. The standard recommends assessment of biofilm reduction using protein or carbohydrate quantification methods. The aim of this study was to assess the suitability of various quantification methods using the ISO biofilm model. The ISO 15883 part 5 biofilm test soil method was used to grow biofilm within lumens representative of endoscopes channels. The biofilm was then quantified using five methods: Crystal Violet (CV), Colony Forming Units (CFU), Total Organic Carbon (TOC), protein assay with Orthophtalaldehyde (OPA), and protein assay by micro bicinchoninic acid (μBCA). The five methods were statistically analyzed for their ability to assess biofilm reduction on samples accurately and precisely. In addition, the quantification methods were compared to demonstrate statistical equivalency, and thus their suitability for assessing biofilm cleaning performance testing of AERs.}, } @article {pmid37937098, year = {2023}, author = {Meredith, K and Coleborn, MM and Metcalf, DG}, title = {Assessment of Silver-Containing Gelling Fiber Dressings Against Antibiotic-Resistant Pathogens Using an in vitro Biofilm Model.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {7015-7019}, pmid = {37937098}, issn = {1178-6973}, } @article {pmid37935892, year = {2023}, author = {Ghosh, D and Seth, M and Mondal, P and Mukhopadhyay, SK}, title = {Biocontrol of biofilm forming Burkholderia cepacia using a quorum quenching crude lactonase enzyme extract from a marine Chromohalobacter sp. strain D23.}, journal = {Archives of microbiology}, volume = {205}, number = {12}, pages = {374}, pmid = {37935892}, issn = {1432-072X}, support = {09/025(0254)/2018-EMR-I//Council of Scientific and Industrial Research, India/ ; }, mesh = {Quorum Sensing/physiology ; *Burkholderia cepacia/metabolism ; *Chromohalobacter/metabolism ; Biofilms ; Acyl-Butyrolactones/metabolism ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Biofilm plays advantageous role in Burkholderia cepacia by exerting multi-drug resistance. As quorum sensing (QS) system regulates biofilm formation and pathogenicity in B. cepacia strains, quorum quenching (QQ) may be a novel strategy to control persistent B. cepacia infections. In these regards, 120 halophilic bacteria were isolated from marine sample and tested using Chromobacterium violaceum and C. violaceum CV026-based bioassays initially, showing reduced violacein synthesis by QQ enzyme by 6 isolates. Among them, Chromohalobacter sp. D23 significantly degraded both C6-homoserine lactone (C6-HSL) and C8-HSL due to potent lactonase activity, which was detected by C. violaceum CV026 biosensor. Further high-performance liquid chromatography (HPLC) study confirmed degradation of N-acyl homoserine lactones (N-AHLs) particularly C6-HSL and C8-HSL by crude lactonase enzyme. Chromohalobacter sp. D23 reduced biofilm formation in terms of decreased total biomass and viability in biofilm-embedded cells in B. cepacia significantly which was also evidenced by fluorescence microscopic images. An increase in antibiotic susceptibility of B. cepacia biofilm was achieved when crude lactonase enzyme of Chromohalobacter sp. strain D23 was combined with chloramphenicol (1-5 × MIC). Chromohalobacter sp. D23 also showed prominent decrease in QS-mediated synthesis of virulence factors such as extracellular polymeric substances (EPS), extracellular protease, and hemolysin in B. cepacia. Again crude lactonase enzyme of Chromohalobacter sp. strain D23 inhibited B. cepacia biofilm formation inside nasal oxygen catheters in vitro. Finally, antibiotic susceptibility test and virulence tests revealed sensitivity of Chromohalobacter sp. strain D23 against a wide range of conventional antibiotics as well as absence of gelatinolytic, hemolytic, and serum coagulating activities. Therefore, the current study shows potential quorum quenching as well as anti-biofilm activity of Chromohalobacter sp. D23 against B. cepacia.}, } @article {pmid37935264, year = {2023}, author = {Moradi, M and Gao, Y and Narenkumar, J and Fan, Y and Gu, T and Carmona-Martinez, AA and Xu, D and Wang, F}, title = {Filamentous marine Gram-positive Nocardiopsis dassonvillei biofilm as biocathode and its electron transfer mechanism.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {168347}, doi = {10.1016/j.scitotenv.2023.168347}, pmid = {37935264}, issn = {1879-1026}, abstract = {This study investigated electrochemical characteristics of Gram-positive, Nocardiopsis dassonvillei B17 facultative bacterium in bioelectrochemical systems. The results demonstrated that anodic and cathodic reaction rates were catalyzed by this bacterium, especially by utilization of aluminium alloy as a substrate. Cyclic voltammogram results depicted an increase of peak current and surface area through biofilm development, confirming its importance on catalysis of redox reactions. Phenazine derivatives were detected and their electron mediating behavior evaluated exogenously. A symmetrical redox peak in the range of -59 to -159 mV/SHE was observed in cyclic voltammogram of bacterial solution supplemented with 12 μM phenazine, a result consistent with cyclic voltammogram of a 5-d biofilm, confirming its importance as an electron mediator in extracellular electron transfer. Furthermore, the dependency of bacterial catalysis and polarization potential were studied. These results suggested that B17 biofilm behaved as a biocathode and transferred electrons to bacterial cells through a mechanism associated with electron mediators.}, } @article {pmid37933754, year = {2023}, author = {Zaini, NNM and Salleh, WMNHW and Arzmi, MH and Salihu, AS and Ab Ghani, N}, title = {Chemical composition of essential oil from Lindera subumbelliflora Kosterm and its effect on the susceptibility and biofilm activities of Candida albicans and Streptococcus mutans.}, journal = {Natural product research}, volume = {}, number = {}, pages = {1-6}, doi = {10.1080/14786419.2023.2278164}, pmid = {37933754}, issn = {1478-6427}, abstract = {The chemical composition of the essential oil of Lindera subumbelliflora (Lauraceae) was investigated for the first time. The essential oil was obtained by hydrodistillation and fully characterised by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity of L. subumbelliflora essential oil was tested against Candida albicans and Streptococcus mutans using the broth microdilution assay, whereas the microbial biofilms were determined using a semi-quantitative static biofilm. A total of 28 components (99.6%) were successfully identified, which were characterised by β-eudesmol (14.6%), cis-α-bergamotene (11.0%), α-copaene (8.5%), dodecen-1-ol (8.5%), and (E)-nerolidol (8.3%). The essential oil exhibited activity against Candida albicans and Streptococcus mutans with MIC values of 250 and 500 µg/mL, respectively. The essential oil increased the biofilm of Candida albicans by 38.25%, however, decreased the biofilm of Streptococcus mutans by 47.89% when treated with 500 µg/mL. Thus, the essential oil has a promising application in dentistry via inhibition of the growth of Candida albicans and Streptococcus mutans. However, the antibiofilm activity of the essential oil is only applicable for cariogenic Streptococcus mutans.}, } @article {pmid37933277, year = {2023}, author = {Yang, S and Li, X and Cang, W and Mu, D and Ji, S and An, Y and Wu, R and Wu, J}, title = {Biofilm tolerance, resistance and infections increasing threat of public health.}, journal = {Microbial cell (Graz, Austria)}, volume = {10}, number = {11}, pages = {233-247}, pmid = {37933277}, issn = {2311-2638}, abstract = {Microbial biofilms can cause chronic infection. In the clinical setting, the biofilm-related infections usually persist and reoccur; the main reason is the increased antibiotic resistance of biofilms. Traditional antibiotic therapy is not effective and might increase the threat of antibiotic resistance to public health. Therefore, it is urgent to study the tolerance and resistance mechanism of biofilms to antibiotics and find effective therapies for biofilm-related infections. The tolerance mechanism and host reaction of biofilm to antibiotics are reviewed, and bacterial biofilm related diseases formed by human pathogens are discussed thoroughly. The review also explored the role of biofilms in the development of bacterial resistance mechanisms and proposed therapeutic intervention strategies for biofilm related diseases.}, } @article {pmid37932582, year = {2023}, author = {Yang, JX and Liu, CW and Wu, FW and Zhu, L and Liang, GW}, title = {Molecular characterization and biofilm formation ability of Enterococcus faecium and Enterococcus faecalis bloodstream isolates from a Chinese tertiary hospital in Beijing.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37932582}, issn = {1618-1905}, support = {2020-4-6084//Capital Health Research and Development of Special Fund, Beijing, China/ ; }, abstract = {To investigate the molecular characteristics and biofilm-forming ability of 116 Enterococcus faecium (Efm) and 72 Enterococcus faecalis (Efs) isolates obtained from patients with bloodstream infections (BSI) at a Chinese hospital between July 2011 and March 2018. The presence of glycopeptide resistance genes and five virulence genes (esp, gelE, asa1, hyl, and cylA) was screened using two multiplex PCR. MLST was used to assess the clonality. Crystal violet staining was used to detect biofilms. Vancomycin resistance was detected in 30.1% of Efm and 2.8% of Efs isolates, respectively. All VRE strains carried the vanA gene. The esp, gelE, asa1, and cylA genes in 72 Efs strains were detected at 62.5%, 84.7%, 84.7%, and 69.4%, respectively. Among the 116 Efm isolates, 74.1% and 25.8% carried esp and hyl, respectively. The esp gene was significantly associated with vancomycin-resistant Efm (VREfm) compared to vancomycin-susceptible Efm (VSEfm). In total, 91.7% of Efs and 20.0% of Efm produced biofilms. Twenty-six STs were identified among the 72 Efs isolates, with ST4 (29.2%) being the predominant. In total, 116 Efm strains were grouped into 26 STs, with ST78 (46.6%) being the predominant. Both VREfm (41.7%) and VSEfm (48.8%) were dominant in ST78. There is no clear evidence suggesting that some STs are associated with vancomycin resistance or biofilm formation. Both Efm and Efs BSI isolates showed a polyclonal pattern with a dominant clone and many unique types, implying the coexistence of clonal dissemination and an influx of new clones. The horizontal transmission of resistance genes may play a more important role in VREfm prevalence than clonal expansion.}, } @article {pmid37932532, year = {2023}, author = {Tarabal, VS and Abud, YKD and da Silva, FG and da Cruz, LF and Fontes, GN and da Silva, JA and Filho, CBS and Sinisterra, RD and Granjeiro, JM and Granjeiro, PA}, title = {Effect of DMPEI coating against biofilm formation on PVC catheter surface.}, journal = {World journal of microbiology & biotechnology}, volume = {40}, number = {1}, pages = {6}, pmid = {37932532}, issn = {1573-0972}, support = {APQ-00855-19//Minas Gerais Research Foundation/ ; 001//Coordination for the Improvement of Higher Education Personnel/ ; 01.18.0156.00 (0054/16)//Funding Authority for Studies and Projects/ ; }, abstract = {Urinary tract infections (UTIs) are a significant cause of morbidity in healthcare systems and are prominently associated with applying urethral catheters, particularly in surgeries. Polyvinyl chloride (PVC) is extensively utilized in the fabrication of catheters. Biofilms, complex polymeric constructions, provide a protective milieu for cell multiplication and the enhancement of antibiotic resistance. Strategies to counteract biofilm development on medical apparatuses' surfaces incorporate antimicrobial agents such as N,N-dodecyl, and methyl polyethylenimine (DMPEI). This research endeavored to characterize the morphology of PVC and PVC-DMPEI surfaces utilizing Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) and to gauge hydrophobicity through contact angle measurements. Employing Escherichia coli, Staphylococcus aureus, and Candida albicans in adhesion assays enabled the assessment of DMPEI's efficacy in preventing microbial adherence to PVC. Butanol successfully solubilized 2 mg.mL[-1] DMPEI without altering the PVC structure. SEM results substantiated the formation of a DMPEI layer on the PVC surface, which led to decreased surface roughness, as validated by AFM, and increased hydrophilicity, as demonstrated by contact angle evaluations. E. coli, S. aureus, and C. albicans exhibited significant adhesion reduction, 89.3%, 94.3%, and 86.6% on PVC-DMPEI surfaces. SEM visualizations confirmed reduced cellular colonization on PVC-DMPEI and highlighted considerable morphological modifications in E. coli. Consequently, DMPEI films effectively minimize the adhesion of E. coli, S. aureus, and C. albicans on PVC surfaces. DMPEI, with its potential as a protective coating for innovative medical devices, promises to inhibit biofilm adherence effectively.}, } @article {pmid37932063, year = {2023}, author = {Gao, H and Ma, LZ and Qin, Q and Cui, Y and Ma, XH and Zhang, YQ and Kan, B}, title = {Protein Containing the GGDEF Domain Affects Motility and Biofilm Formation in Vibrio cholerae and is Negatively Regulated by Fur and HapR.}, journal = {Biomedical and environmental sciences : BES}, volume = {36}, number = {10}, pages = {949-958}, doi = {10.3967/bes2023.080}, pmid = {37932063}, issn = {2214-0190}, abstract = {OBJECTIVE: This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase (DGC) in Vibrio cholerae and how its transcription is regulated by Fur and HapR.

METHODS: The roles of VCA0560 was investigated by utilizing various phenotypic assays, including colony morphological characterization, crystal violet staining, Cyclic di-GMP (c-di-GMP) quantification, and swimming motility assay. The regulation of the VCA0560 gene by Fur and HapR was analyzed by luminescence assay, electrophoretic mobility shift assay, and DNase I footprinting.

RESULTS: VCA0560 gene mutation did not affect biofilm formation, motility, and c-di-GMP synthesis in V. cholerae, and its overexpression remarkably enhanced biofilm formation and intracellular c-di-GMP level but reduced motility capacity. The transcription of the VCA0560 gene was directly repressed by Fur and the master quorum sensing regulator HapR.

CONCLUSION: Overexpressed VCA0560 functions as an active DGC in V. cholerae, and its transcription is repressed by Fur and HapR.}, } @article {pmid37931362, year = {2023}, author = {Li, J and Wu, J and Wang, J and Wang, X}, title = {Phenotypic variations induced emergence of orientation order and morphology in Bacillus subtilis biofilm growth.}, journal = {Biochemical and biophysical research communications}, volume = {686}, number = {}, pages = {149198}, doi = {10.1016/j.bbrc.2023.149198}, pmid = {37931362}, issn = {1090-2104}, abstract = {During the Bacillus subtilis biofilm growth on the solid MSgg substrate, the biofilm exhibits highly ordered structures such as matrix-producing-cell chains and Van Gogh bundles due to bacterial orientation order. These structures make the biofilm have strong mobility and environmental adaptability, thus making bacteria easier to survive and thrive in biofilms comparing to planktonic bacteria. We tested the behaviors of different phenotypes as well as their impacts on bacterial clusters: motile cells arrange disorderly, the biofilm made up of motile cells tends to be circular and isotropic; matrix-producing cells form cellular chains that guide motile cells along the chain to form a locally nematic phase, the morphology of the biofilm made up of both motile cells and matrix-producing cells is rendered irregular. Combining the results of a coarse-grained and individual-based model, we can control the biofilm growth through regulating environmental friction, bacterial growth rate and adhesion between cells.}, } @article {pmid37930514, year = {2023}, author = {Sukmarini, L and Atikana, A and Hertiani, T}, title = {Antibiofilm activity of marine microbial natural products: potential peptide- and polyketide-derived molecules from marine microbes toward targeting biofilm-forming pathogens.}, journal = {Journal of natural medicines}, volume = {}, number = {}, pages = {}, pmid = {37930514}, issn = {1861-0293}, support = {2312/II.7/HK.01.00/7/2022//Badan Riset dan Inovasi Nasional/ ; 2/PKR/PPK-DFRI/2022//Badan Riset dan Inovasi Nasional/ ; 63.31.01/UN1/FFA/UP/SK/2023//Universitas Gadjah Mada/ ; }, abstract = {Controlling and treating biofilm-related infections is challenging because of the widespread presence of multidrug-resistant microbes. Biofilm, a naturally occurring matrix of microbial aggregates, has developed intricate and diverse resistance mechanisms against many currently used antibiotics. This poses a significant problem, especially for human health, including clinically chronic infectious diseases. Thus, there is an urgent need to search for and develop new and more effective antibiotics. As the marine environment is recognized as a promising reservoir of new biologically active molecules with potential pharmacological properties, marine natural products, particularly those of microbial origin, have emerged as a promising source of antibiofilm agents. Marine microbes represent an untapped source of secondary metabolites with antimicrobial activity. Furthermore, marine natural products, owing to their self-defense mechanisms and adaptation to harsh conditions, encompass a wide range of chemical compounds, including peptides and polyketides, which are primarily found in microbes. These molecules can be exploited to provide novel and unique structures for developing alternative antibiotics as effective antibiofilm agents. This review focuses on the possible antibiofilm mechanism of these marine microbial molecules against biofilm-forming pathogens. It provides an overview of biofilm development, its recalcitrant mode of action, strategies for the development of antibiofilm agents, and their assessments. The review also revisits some selected peptides and polyketides from marine microbes reported between 2016 and 2023, highlighting their moderate and considerable antibiofilm activities. Moreover, their antibiofilm mechanisms, such as adhesion modulation/inhibition targeting biofilm-forming pathogens, quorum sensing intervention and inhibition, and extracellular polymeric substance disruption, are highlighted herein.}, } @article {pmid37928621, year = {2023}, author = {Laulund, AS and Schwartz, FA and Høiby, N and Thomsen, K and Moser, C}, title = {Hyperbaric oxygen therapy counteracts Pseudomonas aeruginosa biofilm micro-compartment phenomenon in murine thermal wounds.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100159}, pmid = {37928621}, issn = {2590-2075}, abstract = {BACKGROUND: Biofilm antibiotic tolerance is partly explained by the behavior of a biofilm as an independent pharmacokinetic micro-compartment. Hyperbaric oxygen therapy has been shown to potentiate antibiotic effects in biofilms. The present study investigates the effect of hyperbaric oxygen therapy (HBOT) on the biofilm micro-pharmacokinetic/pharmacodynamic behavior of tobramycin in an animal biofilm model.

METHODS: Full-thickness necroses were created mid-scapular on mice by means of a thermal lesion. After four days, three 16 h seaweed alginate biofilm beads containing Pseudomonas aeruginosa PAO1 were inserted under the necrosis, and three beads were inserted under the adjacent non-affected skin. The mice were randomized to three groups I) HBOT for 1.5 h at 2.8 atm and 0.8 mg tobramycin/mouse subcutaneously; II) Tobramycin as monotherapy, same dose; III) Saline control group. Half the number of mice from group 1 and 2 were sacrificed, and beads were recovered in toto after 3 h and the other half and the placebo mice were sacrificed and beads collected after 4.5 h.

RESULTS: Lower CFUs were seen in the burned group receiving HBOT at 3 and 4.5 h compared to beads in the atmospheric environment (p = 0.043 and p = 0.0089). At 3 h, no CFU difference was observed in the non-burned skin (HBOT vs atmospheric). At 4.5 h, CFU in the non-burned skin had lower CFUs in the group receiving HBOT compared to the corresponding atmospheric group (p = 0.02). CFU was higher in the burned skin than in the non-burned skin at 3 h when HBOT was applied (p = 0.04), effect faded out at 4.5 h.At both time points, the tobramycin content in the beads under burned skin were higher in the HBOT group than in the atmospheric groups (p = 0.031 and p = 0.0078). Only at 4.5 h a higher tobramycin content was seen in the beads under the HBOT-treated burned skin than the beads under the corresponding non-burned skin (p = 0.006).

CONCLUSION: HBOT, as an anti-biofilm adjuvant treatment of chronic wounds, counteracts biofilm pharmacokinetic micro-compartmentalization through increased available tobramycin and augmented bacterial killing.}, } @article {pmid37928620, year = {2023}, author = {Wang, D and Naqvi, STA and Lei, F and Zhang, Z and Yu, H and Ma, LZ}, title = {Glycosyl hydrolase from Pseudomonas fluorescens inhibits the biofilm formation of Pseudomonads.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100155}, pmid = {37928620}, issn = {2590-2075}, abstract = {Biofilms are complex microbial communities embedded in extracellular matrix. Pathogens within the biofilm become more resistant to the antibiotics than planktonic counterparts. Novel strategies are required to encounter biofilms. Exopolysaccharides are one of the major components of biofilm matrix and play a vital role in biofilm architecture. In previous studies, a glycosyl hydrolase, PslGPA, from Pseudomonas aeruginosa was found to be able to inhibit biofilm formation by disintegrating exopolysaccharide in biofilms. Here, we investigate the potential spectrum of PslG homologous protein with anti-biofilm activity. One glycosyl hydrolase from Pseudomonas fluorescens, PslGPF, exhibits anti-biofilm activities and the key catalytic residues of PslGPF are conserved with those of PslGPA. PslGPF at concentrations as low as 50 nM efficiently inhibits the biofilm formation of P. aeruginosa and disassemble its preformed biofilm. Furthermore, PslGPF exhibits anti-biofilm activity on a series of Pseudomonads, including P. fluorescens, Pseudomonas stutzeri and Pseudomonas syringae pv. phaseolicola. PslGPF stays active under various temperatures. Our findings suggest that P. fluorescens glycosyl hydrolase PslGPF has potential to be a broad spectrum inhibitor on biofilm formation of a wide range of Pseudomonads.}, } @article {pmid37927230, year = {2023}, author = {Nie, H and Nie, L and Xiao, Y and Song, M and Zhou, T and He, J and Chen, W and Huang, Q}, title = {The phosphodiesterase DibA interacts with the c-di-GMP receptor LapD and specifically regulates biofilm in Pseudomonas putida.}, journal = {Molecular microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mmi.15189}, pmid = {37927230}, issn = {1365-2958}, support = {2662022SKQD002//Fundamental Research Funds for the Central Universities/ ; 42020104003//National Natural Science Foundation of China/ ; 31900040//National Natural Science Foundation of China/ ; 31900054//National Natural Science Foundation of China/ ; }, abstract = {The ubiquitous bacterial second messenger c-di-GMP is synthesized by diguanylate cyclase and degraded by c-di-GMP-specific phosphodiesterase. The genome of Pseudomonas putida contains dozens of genes encoding diguanylate cyclase/phosphodiesterase, but the phenotypical-genotypical correlation and functional mechanism of these genes are largely unknown. Herein, we characterize the function and mechanism of a P. putida phosphodiesterase named DibA. DibA consists of a PAS domain, a GGDEF domain, and an EAL domain. The EAL domain is active and confers DibA phosphodiesterase activity. The GGDEF domain is inactive, but it promotes the phosphodiesterase activity of the EAL domain via binding GTP. Regarding phenotypic regulation, DibA modulates the cell surface adhesin LapA level in a c-di-GMP receptor LapD-dependent manner, thereby inhibiting biofilm formation. Moreover, DibA interacts and colocalizes with LapD in the cell membrane, and the interaction between DibA and LapD promotes the PDE activity of DibA. Besides, except for interacting with DibA and LapD itself, LapD is found to interact with 11 different potential diguanylate cyclases/phosphodiesterases in P. putida, including the conserved phosphodiesterase BifA. Overall, our findings demonstrate the functional mechanism by which DibA regulates biofilm formation and expand the understanding of the LapD-mediated c-di-GMP signaling network in P. putida.}, } @article {pmid37926364, year = {2023}, author = {Pradhan, J and Pradhan, D and Sahu, JK and Mishra, S and Mallick, S and Das, S and Negi, VD}, title = {A novel rspA gene regulates biofilm formation and virulence of Salmonella Typhimurium.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106432}, doi = {10.1016/j.micpath.2023.106432}, pmid = {37926364}, issn = {1096-1208}, abstract = {Salmonella spp. are facultative anaerobic, Gram-negative, rod-shaped bacteria and belongs to the Enterobacteriaceae family. Although much has been known about Salmonella pathogenesis, the functional characterizations of certain genes are yet to be explored. The rspA (STM14_1818) is one such gene with putative dehydratase function, and its role in pathogenesis is unknown. The background information showed that rspA gene is upregulated in Salmonella when it resides inside macrophages, which led us to investigate its role in Salmonella pathogenesis. We generated the rspA knockout strain and complement strain in S. Typhimurium 14,028. Ex-vivo and in-vivo infectivity was looked at macrophage and epithelial cell lines and Caenorhabditis elegans (C. elegans). The mutant strain differentially formed the biofilm at different temperatures by altering the expression of genes involved in the synthesis of cellulose and curli. Besides, the mutant strain is hyperproliferative intracellularly and showed increased bacterial burden in C. elegans. The mutant strain became more infectious and lethal, causing faster death of the worms than the wild type, and also modulates the worm's innate immunity. Thus, we found that the rspA deletion mutant was more pathogenic. In this study, we concluded that the rspA gene differentially regulates the biofilm formation in a temperature dependent manner by modulating the genes involved in the synthesis of cellulose and curli and negatively regulates the Salmonella virulence for longer persistence inside the host.}, } @article {pmid37923285, year = {2023}, author = {Fernandes, JA and Conrado, PCV and Perina, BS and de Oliveira, ACV and Arita, GS and Capoci, IRG and Gonçalves, RS and Caetano, W and Svidzinski, TIE and Cotica, ESK and Bonfim-Mendonça, PS}, title = {Photodynamic inactivation by hypericin-P123 on azole-resistant isolates of the Trichophyton rubrum complex as planktonic cells and biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {}, number = {}, pages = {103875}, doi = {10.1016/j.pdpdt.2023.103875}, pmid = {37923285}, issn = {1873-1597}, abstract = {INTRODUCTION: The Trichophyton rubrum complex comprises the majority of dermatophyte fungi (DM) responsible for chronic cases of onychomycosis, which is treated with oral or topical antifungals. However, owing to antifungal resistance, alternative therapies, such as photodynamic therapy (PDT), are needed. This study investigated the frequency of the T. rubrum species complex in onychomycosis cases in the northwestern region of Paraná state, Brazil, and evaluated the efficacy of (PDT) using P123-encapsulated hypericin (Hyp-P123) on clinical isolates of T. rubrum in the planktonic cell and biofilm forms.

MATERIAL AND METHODS: The frequency of the T. rubrum complex in onychomycosis cases from 2017 to 2021 was evaluated through a data survey of records from the Laboratory of Medical Mycology (LEPAC) of the State University of Maringa (UEM). To determine the effect of PDT-Hyp-P123 on planktonic cells of T. rubrum isolates, 1×10[5] conidia/mL were treated with ten different concentrations of Hyp-P123 and then irradiated with 37.8 J/cm[2]. Antibiofilm activity of PDT-Hyp-P123 was tested against T. rubrum biofilm in the adhesion phase (3 h), evaluated 72 h after irradiation (37.8 J/cm[2]), and the mature biofilm (72 h), evaluated immediately after irradiation. In this context, three different parameters were evaluated: cell viability, metabolic activity and total biomass.

RESULTS: The T. rubrum species complex was the most frequently isolated DM in onychomycosis cases (approximately 80%). A significant reduction in fungal growth was observed for 75% of the clinical isolates tested with a concentration from 0.19 μmol/L Hyp-P123, and 56.25% had complete inhibition of fungal growth (fungicidal action); while all isolates were azole-resistant. The biofilm of T. rubrum isolates (TR0022 and TR0870) was inactivated in both the adhesion phase and the mature biofilm.

CONCLUSION: PDT-Hyp-P123 had antifungal and antibiofilm activity on T. rubrum, which is an important dermatophyte responsible for onychomycosis cases.}, } @article {pmid37926271, year = {2023}, author = {Fan, J and Jia, Y and He, S and Tan, Z and Li, A and Li, J and Zhang, Z and Li, B and Chu, H}, title = {GlnR Activated Transcription of Nitrogen Metabolic Pathway Genes Facilitates Biofilm Formation by Mycobacterium abscessus.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {107025}, doi = {10.1016/j.ijantimicag.2023.107025}, pmid = {37926271}, issn = {1872-7913}, abstract = {Nitrogen is indispensable for the synthesis of biomacromolecules. The correlation between nitrogen metabolism and Mycobacterium abscessus (M. abscessus) biofilm formation is unclear. Global nitrogen regulator gene GlnR (Mab_0744) knockout (ΔglnR) and complementation (ΔglnR::glnR) M. abscessus strains were constructed. GlnR knockout decreased the growth rate of planktonic cells, reduced biofilm mass and wrinkle formation, and diminished the resistance of biofilms to antibiotics. The susceptibility of planktonic cells to antibiotics, however, was not changed by glnR knockout. The growth rate of planktonic ΔglnR cells was accelerated by adding nitrogen sources to the medium; particularly, the addition of glutamine or sodium glutamate rescued ΔglnR biofilm morphology and resistance to amikacin, cefoxitin, clarithromycin and imipenem. GlnR bound the promoter region and activated the transcription of eight nitrogen metabolic pathway genes (i.e., glnA, amt, ansP, nirB, nirD, glnD, glnK and narK3), which are closely related to glutamine/glutamate biosynthesis and, thus, regulate biofilm formation. Our study provides insights into the mechanisms of M. abscessus biofilm formation and its resistance to antibiotics.}, } @article {pmid37925405, year = {2023}, author = {Roshani, M and Taheri, M and Goodarzi, A and Yosefimashouf, R and Shokoohizadeh, L}, title = {Evaluation of antibiotic resistance, toxin-antitoxin systems, virulence factors, biofilm-forming strength and genetic linkage of Escherichia coli strains isolated from bloodstream infections of leukemia patients.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {327}, pmid = {37925405}, issn = {1471-2180}, abstract = {BACKGROUND: One of the most common complications in patients with febrile neutropenia, lymphoma, leukemia, and multiple myeloma is a bloodstream infection (BSI).

OBJECTIVE: This study aimed to evaluate the antibiotic resistance patterns, virulence factors, biofilm-forming strength, and genetic linkage of Escherichia coli strains isolated from bloodstream infections (BSIs) of leukemia patients.

METHODS: The study conducted in Iran from June 2021 to December 2022, isolated 67 E. coli strains from leukemia patients' bloodstream infections in hospitals in two different areas. Several techniques including disk diffusion and broth microdilution were used to identify patterns of antibiotic resistance, microtiter plate assay to measure biofilm formation, and PCR to evaluate the prevalence of different genes such as virulence factors, toxin-antitoxin systems, resistance to β-lactams and fluoroquinolone antibiotics of E. coli strains. Additionally, the genetic linkage of the isolates was analyzed using the Enterobacterial Repeat Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) method.

RESULTS: The results showed that higher frequency of BSI caused by E. coli in man than female patients, and patients with acute leukemia had a higher frequency of BSI. Ampicillin and Amoxicillin-clavulanic acid showed the highest resistance, while Imipenem was identified as a suitable antibiotic for treating BSIs by E. coli. Multidrug-resistant (MDR) phenotypes were present in 22% of the isolates, while 53% of the isolates were ESBL-producing with the blaCTX-M gene as the most frequent β-lactamase gene. The fluoroquinolone resistance genes qnrB and qnrS were present in 50% and 28% of the isolates, respectively. More than 80% of the isolates showed the ability to form biofilms. The traT gene was more frequent than other virulence genes. The toxin-antitoxin system genes (mazF, ccdAB, and relB) showed a comparable frequency. The genetic diversity was detected in E. coli isolates.

CONCLUSION: Our results demonstrate that highly diverse, resistant and pathogenic E. coli clones are circulating among leukemia patients in Iranian hospitals. More attention should be paid to the treatment and management of E. coli bloodstream infections in patients with leukemia.}, } @article {pmid37925312, year = {2023}, author = {Oshiki, M and Saito, T and Nakaya, Y and Satoh, H and Okabe, S}, title = {Growth of the Nitrosomonas europaea cells in the biofilm and planktonic growth mode: Responses of extracellular polymeric substances production and transcriptome.}, journal = {Journal of bioscience and bioengineering}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jbiosc.2023.10.002}, pmid = {37925312}, issn = {1347-4421}, abstract = {Nitrosomonas europaea, an aerobic ammonia oxidizing bacterium, is responsible for the first and rate-limiting step of the nitrification process, and their ammonia oxidation activities are critical for the biogeochemical cycling and the biological nitrogen removal of wastewater treatment. In the present study, N. europaea cells were cultivated in the inorganic or organic media (the NBRC829 and the nutrient-rich, NR, media, respectively), and the cells proliferated in the form of planktonic and biofilm in those media, respectively. The N. europaea cells in the biofilm growth mode produced larger amounts of the extracellular polymeric substances (EPS), and the composition of the EPS was characterized by the chemical analyses including Fourier transform infrared spectroscopy (FT-IR) and [1]H-nuclear magnetic resonance (NMR) measurements. The RNA-Seq analysis of N. europaea in the biofilm or planktonic growth mode revealed that the following gene transcripts involved in central nitrogen metabolisms were abundant in the biofilm growth mode; amo encoding ammonia monooxygenase, hao encoding hydroxylamine dehydrogenase, the gene encoding nitrosocyanine, nirK encoding copper-containing nitrite reductase. Additionally, the transcripts of the pepA and wza involved in the bacterial floc formation and the translocation of EPS, respectively, were also abundant in the biofilm-growth mode. Our study was first to characterize the EPS production and transcriptome of N. europaea in the biofilm and planktonic growth mode.}, } @article {pmid37924909, year = {2023}, author = {Morris, SD and Kumar, VA and Biswas, R and Mohan, CG}, title = {Identification of a Staphylococcus aureus amidase catalytic domain inhibitor to prevent biofilm formation by sequential virtual screening, molecular dynamics simulation and biological evaluation.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127842}, doi = {10.1016/j.ijbiomac.2023.127842}, pmid = {37924909}, issn = {1879-0003}, abstract = {Staphylococcus aureus (S. aureus) is one of the common causes of implant associated biofilm infections and their biofilms are resistant to antibiotics. S. aureus amidase (AM) protein, a cell wall hydrolase that cleaves the amide bond between N-acetylmuramic acid and L-alanine residue of the stem peptide, is several fold over-expressed under biofilm conditions. Previous studies demonstrated an autolysin mutant in S. aureus that lacks the AM protein, is highly impaired in biofilm development. We carried out a structure-based small molecule design using the crystal structure of AM protein catalytic domain to identify inhibitors that can block amidase activity and therefore inhibits S. aureus biofilm formation. Sequential virtual screening followed by pharmacokinetic analysis and bioassay studies filtered 25 small molecules from different databases. Two compounds from the SPECS database, SPECS-1 and SPECS-2, were selected based on the best docking score and minimum biofilm inhibitory concentration towards S. aureus biofilms. SPECS-1 and SPECS-2 were further tested for their structural/energetic stability in complex with the AM protein using molecular dynamics simulation and MM-GBSA techniques. In vitro, biofilm inhibition studies on different surfaces confirmed that treatment with SPECS-1 and SPECS-2 at a concentration of 250 μg/ml exhibited significant prevention and disruption of S. aureus biofilms. Finally, the in vitro anti-biofilm activities of these two compounds were validated against Methicillin-resistant S. aureus clinical isolates. We concluded that the discovered compounds SPECS-1 and SPECS-2 are safe and exhibit biofilm preventive and disruption activity for inhibiting the S. aureus biofilms and hence can be used to treat implant-associated biofilm infections.}, } @article {pmid37924358, year = {2023}, author = {Ev, LD and Poloni, JF and Damé-Teixeira, N and Arthur, RA and Corralo, DJ and Henz, SL and Do, T and Maltz, M and Parolo, CCF}, title = {Hub genes and pathways related to caries-free dental biofilm: clinical metatranscriptomic study.}, journal = {Clinical oral investigations}, volume = {}, number = {}, pages = {}, pmid = {37924358}, issn = {1436-3771}, abstract = {OBJECTIVE: This study aimed to evaluate the microbial functional profile of biofilms related to caries-free (CF, n = 6) and caries-arrested (CI, n = 3) compared to caries-active (CA, n = 5) individuals.

MATERIALS AND METHODS: A metatranscriptomic was performed in supragingival biofilm from different clinical conditions related to caries or health. Total RNA was extracted and cDNAs were obtained and sequenced (Illumina HiSeq3000). Trimmed data (SortMeRNA) were submitted to the SqueezeMeta pipeline in the co-assembly mode for functional analysis and further differential gene expression analysis (DESeq2) and weighted gene co-expression network analysis (WCGNA) to explore and identify gene modules related to these clinical conditions.

RESULTS: A total of 5303 genes were found in the metatranscriptomic analysis. A co-expression network identified the most relevant modules strongly related to specific caries status. Correlation coefficients were calculated between the eigengene modules and the clinical conditions (CA, CI, and CF) discriminating multiple modules. CA and CI showed weak correlation coefficient strength across the modules, while the CF condition presented a very strong positive correlation coefficient (r = 0.9, p value = 4 × 10[-9]). Pearson's test was applied to further analyze the module membership and gene significance in CF conditions, and the most relevant were HSPA1s-K03283, Epr- K13277, and SLC1A-K05613. Gene Ontology (GO) shows important bioprocesses, such as two-component system, fructose and mannose metabolism, pentose and glucuronate interconversions, and flagellar assembly (p-adjust < 0.05). The ability to use different carbohydrates, integrate multiple signals, swarm, and bacteriocin production are significant metabolic advantages in the oral environment related to CF.

CONCLUSIONS: A distinct functional health profile could be found in CF, where co-occurring genes can act in different pathways at the same time. Genes HSPA1s, Epr, and SLC1A may be appointed as potential biomarkers for caries-free biofilms.

CLINICAL RELEVANCE: Potential biomarkers for caries-free biofilms could contribute to the knowledge of caries prevention and control.}, } @article {pmid37922428, year = {2023}, author = {Capri, FC and Di Leto, Y and Presentato, A and Mancuso, I and Scatassa, ML and Alduina, R}, title = {Characterization of Staphylococcus Species Isolates from Sheep Milk with Subclinical Mastitis: Antibiotic Resistance, Enterotoxins, and Biofilm Production.}, journal = {Foodborne pathogens and disease}, volume = {}, number = {}, pages = {}, doi = {10.1089/fpd.2023.0003}, pmid = {37922428}, issn = {1556-7125}, abstract = {Subclinical mastitis represents one of the most contagious diseases affecting animals involved in dairy production systems. Although coagulase-negative staphylococci (CoNSs) have been considered minor pathogens for many years, they have recently emerged as opportunistic pathogens in mastitis disorders. The objectives of this work were to assess the antimicrobial resistance profile and the ability to produce a biofilm in comparison with a reference strain and to search for genes related to biofilm production, antimicrobial resistance, and enterotoxins in 18 isolates of Staphylococcus species from the milk of sheep with subclinical mastitis, collected from different Sicilian farms. This knowledge is essential to provide basic information on the pathogenicity and virulence of staphylococcal species and their impact on animal health. All isolates were resistant to ampicillin, 88.8% to streptomycin, 77.7% to gentamicin, 44.4% to chloramphenicol, 27.7% to erythromycin, and 11.1% to tetracycline, and two isolates were strong biofilm producers. Antibiotic resistance gene profiling showed that 16.6% of isolates possess the blaZ gene, whereas the search of biofilm-associated genes revealed the occurrence of the sasC gene in 33.3% of isolates, the ica gene in 27.7%, and bap and agr (accessory gene regulator) genes in 16.6% of isolates. Altogether, the results of this study indicate that CoNSs can acquire virulence genes and could have a role as pathogens in subclinical mastitis.}, } @article {pmid37922031, year = {2023}, author = {Esfahani, MB and Khodavandi, A and Alizadeh, F and Bahador, N}, title = {Possible Molecular Targeting of Biofilm-Associated Genes by Nano-Ag in Candida albicans.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37922031}, issn = {1559-0291}, abstract = {The treatment of candidiasis infections is hindered by the presence of biofilms. Here, we report the biofilm-associated genes as potential molecular targets by silver nanoparticles (nano-Ag) in Candida albicans. Nano-Ag was biosynthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. The physicochemical properties of the microbial-synthesized of nano-Ag are widely characterized by visual observation, ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. Characterization results revealed the formation of nano-Ag. Antiplanktonic cells and antibiofilm activities of nano-Ag were also demonstrated by minimum inhibition concentrations (MIC), minimum fungicidal concentration (MFC), MFC/MIC ratio, crystal violet staining, 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT), and microscopic image analysis. We have analyzed the expressions of biofilm-associated genes in C. albicans treated with different concentrations of nano-Ag based on MIC. The expression profile of BCR1, ALS1, ALS3, HWP1, and ECE1 showed downregulated genes involved in these pathways by the treatment with nanoparticles. Negative regulators, TUP1, NRG1, and TOR1, were upregulated by the treatment of nano-Ag. Our study suggests that nano-Ag affects gene expression and may subsequently decrease the pathogenesis of C. albicans by inhibiting biofilm formation. Molecular targeting of biofilm-associated genes involved in biofilm formation by nano-Ag may be an effective treatment strategy for candidiasis infections.}, } @article {pmid37919227, year = {2023}, author = {Amyx-Sherer, K and Reichhardt, C}, title = {Challenges and opportunities in elucidating the structures of biofilm exopolysaccharides: A case study of the Pseudomonas aeruginosa exopolysaccharide called Pel.}, journal = {Magnetic resonance in chemistry : MRC}, volume = {}, number = {}, pages = {}, doi = {10.1002/mrc.5405}, pmid = {37919227}, issn = {1097-458X}, abstract = {Biofilm formation protects bacteria from antibiotic treatment and host immune responses, making biofilm infections difficult to treat. Within biofilms, bacterial cells are entangled in a self-produced extracellular matrix that typically includes exopolysaccharides. Molecular-level descriptions of biofilm matrix components, especially exopolysaccharides, have been challenging to attain due to their complex nature and lack of solubility and crystallinity. Solid-state nuclear magnetic resonance (NMR) has emerged as a key tool to determine the structure of biofilm matrix exopolysaccharides without degradative sample preparation. In this review, we discuss challenges of studying biofilm matrix exopolysaccharides and opportunities to develop solid-state NMR approaches to study these generally intractable materials. We specifically highlight investigations of the exopolysaccharide called Pel made by the opportunistic pathogen, Pseudomonas aeruginosa. We provide a roadmap for determining exopolysaccharide structure and discuss future opportunities to study such systems using solid-state NMR. The strategies discussed for elucidating biofilm exopolysaccharide structure should be broadly applicable to studying the structures of other glycans.}, } @article {pmid37918886, year = {2023}, author = {Ching, C and Brychcy, M and Nguyen, B and Muller, P and Pearson, AR and Downs, M and Regan, S and Isley, B and Fowle, W and Chai, Y and Godoy, VG}, title = {RecA levels modulate biofilm development in Acinetobacter baumannii.}, journal = {Molecular microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mmi.15188}, pmid = {37918886}, issn = {1365-2958}, support = {NUSci, an Inclusive Excellence award from HHMI/HHMI/Howard Hughes Medical Institute/United States ; }, abstract = {Infections caused by Acinetobacter baumannii, a Gram-negative opportunistic pathogen, are difficult to eradicate due to the bacterium's propensity to quickly gain antibiotic resistances and form biofilms, a protective bacterial multicellular community. The A. baumannii DNA damage response (DDR) mediates the antibiotic resistance acquisition and regulates RecA in an atypical fashion; both RecA[Low] and RecA[High] cell types are formed in response to DNA damage. The findings of this study demonstrate that the levels of RecA can influence formation and dispersal of biofilms. RecA loss results in surface attachment and prominent biofilms, while elevated RecA leads to diminished attachment and dispersal. These findings suggest that the challenge to treat A. baumannii infections may be explained by the induction of the DDR, common during infection, as well as the delicate balance between maintaining biofilms in low RecA cells and promoting mutagenesis and dispersal in high RecA cells. This study underscores the importance of understanding the fundamental biology of bacteria to develop more effective treatments for infections.}, } @article {pmid37918765, year = {2023}, author = {Kampouraki, ZC and Petala, M and Zacharias, K and Konstantinidis, A and Zabulis, X and Karamaounas, P and Kostoglou, M and Karapantsios, TD}, title = {Highly sensitive resistance spectroscopy technique for online monitoring of biofilm growth on metallic surfaces.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117401}, doi = {10.1016/j.envres.2023.117401}, pmid = {37918765}, issn = {1096-0953}, abstract = {Online techniques for monitoring biofilm formation and evolution are limited, especially as regards its application in flowing water systems. This is chiefly due to the absence of efficient non-destructive and non-invasive sensing methods. In this study, a sensitive electrical resistance spectroscopy technique is developed to monitor non-invasively and in real time the growth of biofilms over metallic surfaces inside water flow systems. To this aim, Pseudomonas fluorescens strain is used for biofilm development lasting 72 h in a laboratory-scale test channel of orthogonal cross section. Biofilm development corresponds to a progressively increasing coverage of the metallic surface area up to full coverage and a progressively increasing thickness. Biofilm development is registered by continuous recording of electrical impedance signals (time series). Proper configuration and tuning of the electronics promote the resistive contribution to the signal whereas careful grounding diminishes electrical interferences and yields superb sensing sensitivity. An increase of relative electrical resistance of around 15% is noticed in 72 h flow experiments which is attributed to both an increase of metallic surface area coverage and an increase of biofilm thickness. An independent estimation of these quantities using imaging tools and microscopy analysis, indicates that full coverage of the metallic surface occurs after only 48 h of the flow experiment, whereas biofilm thickness increases gradually along the entire 72 h of the experiment. Cross-examination of electrical signals with biofilm characteristics (metallic surface coverage and biofilm thickness) reveals that, qualitatively speaking, electrical signals are rather more sensitive to metallic surface coverage than biofilm thickness.}, } @article {pmid37918593, year = {2023}, author = {Huang, Q and Yang, Z and Tao, X and Ma, C and Cao, P and Wei, P and Jiang, C and Ren, H and Li, X}, title = {Sprayable chitosan nanogel with nitric oxide to accelerate diabetic wound healing through bacteria inhibition, biofilm eradication and macrophage polarization.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127806}, doi = {10.1016/j.ijbiomac.2023.127806}, pmid = {37918593}, issn = {1879-0003}, abstract = {Bacterial infection and chronic inflammation are two major risks in diabetic wound healing, which increase patient mortality. In this study, a multifunctional sprayable nanogel (Ag-G@CS) based on chitosan has been developed to synergistically inhibit bacterial infection, eradicate biofilm, and relieve inflammation of diabetic wounds. The nanogel is successfully crafted by encapsulating with a nitric oxide (NO) donor and performing in-situ reduction of silver nanoparticles (Ag). The released NO enhances the antibacterial efficacy of Ag, nearly achieving complete eradication of biofilms in vitro. Upon application on both normal or diabetic chronic wounds, the combination effects of released NO and Ag offer a notable antibacterial effect. Furthermore, after bacteria inhibition and biofilm eradication, the NO released by the nanogel orchestrates a transformation of M1 macrophages into M2 macrophages, significantly reducing tumor necrosis factor α (TNF-α) release and relieving inflammation. Remarkably, the released NO also promotes M2a to M2c macrophages, thereby facilitating tissue remodeling in chronic wounds. More importantly, it upregulates the expression of vascular endothelial growth factor (VEGF), further accelerating the wound healing process. Collectively, the formed sprayable nanogel exhibits excellent inhibition of bacterial infections and biofilms, and promotes chronic wound healing via inflammation resolution, which has excellent potential for clinical use in the future.}, } @article {pmid37918493, year = {2023}, author = {Lv, PL and Jia, C and Guo, X and Zhao, HP and Chen, R}, title = {Microbial stratification protects denitrifying anaerobic methane oxidation archaea and bacteria from external oxygen shock in membrane biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129966}, doi = {10.1016/j.biortech.2023.129966}, pmid = {37918493}, issn = {1873-2976}, abstract = {Different gradients of dissolved oxygen (DO) regulate the microbial community and nitrogen removal pathways of denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (Anammox) coupled process in a batch biofilm reactor. Under completely anaerobic condition, approximately 72 mg NO3[-]-N/L was removed at a daily rate of 6.55 mg N/L, whereas a peak accumulation of 95 mg NO3[-]-N/L was observed during DO reached 0.5 mg/L. There is a decrease in the abundance of Candidatus Methylomirabilis (24.1%), Candidatus Methanoperedens (23.3%), and Candidatus Kuenenia (22.6%) to below 5% when DO levels reached 0.2 mg/L. Moreover, key genes associated with the reverse methanogenesis (mcrA) and anaerobic ammonium oxidase (hzo) decreased. These findings indicate that during oxygen shock, methanotrophs and denitrifiers replace Anammox bacteria on the outer sphere of the biofilm, whereas DAMO bacteria and archaea are protected from external oxygen shock due to the microbial stratification of biofilm.}, } @article {pmid37918070, year = {2023}, author = {Larsson, Y and Mongelli, A and Kisielius, V and Bester, K}, title = {Microbial biofilm metabolization of benzalkonium compounds (benzyl dimethyl dodecyl ammonium & benzyl dimethyl tetradecyl ammonium chloride).}, journal = {Journal of hazardous materials}, volume = {463}, number = {}, pages = {132834}, doi = {10.1016/j.jhazmat.2023.132834}, pmid = {37918070}, issn = {1873-3336}, abstract = {Benzalkonium chlorides (BACs) are quaternary ammonium compounds (QUATs) that are used as biocides. The degradation of these compounds in wastewater treatment plants is essential to reduce their spread into the environment and thus prevent the development of QUAT-resistant genes. The biodegradation of two BACs (BAC-12 and BAC-14) was investigated in moving bed biofilm reactors (MBBRs). Degradation half-lives of 12 and 20 h for BAC-12 and - 14, respectively, were detected as well as the formation of 42 metabolites. Two new degradation pathways for the BACs were identified in this study: 1) one involving an ω-oxidation, followed by β-oxidation and 2) one via an ω-oxidation followed by an α-oxidation that was succeeded by β-oxidation. Similar metabolites were detected for both BAC-12 and BAC-14. Additional metabolites were detected in the study, that could not be assigned to the above-mentioned pathways, revealing even more metabolic pathways in the MBBR which is probably due to the complexity of the microbial community in the biofilm. Interestingly, both TP194 (Benzyl-(carboxymethyl)-dimethylazanium) and TP208B (Benzyl-(2-carboxyethyl)-dimethylazanium) were identified as end products of the ω/β-pathway and the α/β-pathway. TP208B, TP152 and TP250 that were identified in this study, as well as the known BDMA were discovered in the effluent of a wastewater treatment plant.}, } @article {pmid37919014, year = {2024}, author = {Ekonomou, SI and Boziaris, IS}, title = {Fate of osmotically adapted and biofilm Listeria monocytogenes cells after exposure to salt, heat, and liquid smoke, mimicking the stresses induced during the processing of hot smoked fish.}, journal = {Food microbiology}, volume = {117}, number = {}, pages = {104392}, doi = {10.1016/j.fm.2023.104392}, pmid = {37919014}, issn = {1095-9998}, abstract = {The study aimed to investigate the response of osmotically adapted and detached biofilm Listeria monocytogenes cells following sequential stresses that occur during the processing of hot smoking, such as heating and smoke application. Thermal resistance of L. monocytogenes was significantly affected by previous osmotic adaptation of the cells. D60oC-values of osmotically adapted L. monocytogenes cells were significantly higher than control cells. The osmotically adapted and subsequently heat-injured cells were more resistant to PALCAM and less resistant to TSAYE with 5.00% NaCl (TSAYE/NaCl) than control cells. Detached biofilm cells were more thermotolerant and less resistant to PALCAM and TSAYE/NaCl than control cells. The sequential effect of smoking against heat-treated (60 °C, 20 min) and osmotically adapted or detached L. monocytogenes biofilm cells was investigated using two liquid smoke extracts (L9 and G6). L9 led to significantly higher reductions (>3.00-Log CFU) compared to G6. The heat-treated, detached biofilm cells revealed resistance to L9, presumably due to metabolic downregulation and physical protection by the extracellular polymeric substances (EPS). These data highlight the potential of the food industry to make informed decisions for using safe heat treatments during hot smoking to effectively inactivate L. monocytogenes and maintain rigorous environmental sanitation practices to control biofilm cells.}, } @article {pmid37919011, year = {2024}, author = {Yu, H and Lin, J and Wang, M and Ying, S and Yuan, S and Guo, Y and Xie, Y and Yao, W}, title = {Molecular and proteomic response of Pseudomonas fluorescens biofilm cultured on lettuce (Lactuca sativa L.) after ultrasound treatment at different intensity levels.}, journal = {Food microbiology}, volume = {117}, number = {}, pages = {104387}, doi = {10.1016/j.fm.2023.104387}, pmid = {37919011}, issn = {1095-9998}, abstract = {Ultrasonic treatment is widely used for surface cleaning of vegetables in the processing of agricultural products. In the present study, the molecular and proteomic response of Pseudomonas fluorescens biofilm cultured on lettuce was investigated after ultrasound treatment at different intensity levels. The results show that the biofilm was efficiently removed after ultrasound treatment with intensity higher than 21.06 W/cm[2]. However, at an intensity of less than 18.42 W/cm[2], P. fluorescens was stimulated by ultrasound leading to promoted bacterial growth, extracellular protease activity, extracellular polysaccharide secretion (EPS), and synthesis of acyl-homoserine lactones (AHLs) as quorum-sensing signaling molecules. The expression of biofilm-related genes, stress response, and dual quorum sensing system was upregulated during post-treatment ultrasound. Proteomic analysis showed that ultrasound activated proteins in the flagellar system, which led to changes in bacterial tendency; meanwhile, a large number of proteins in the dual-component system began to be regulated. ABC transporters accelerated the membrane transport of substances inside and outside the cell membrane and equalized the permeability conditions of the cell membrane. In addition, the expression of proteins related to DNA repair was upregulated, suggesting that bacteria repair damaged DNA after ultrasound exposure.}, } @article {pmid37919010, year = {2024}, author = {Palud, A and Roullier-Gall, C and Alexandre, H and Weidmann, S}, title = {Mixed biofilm formation by Oenococcus oeni and Saccharomyces cerevisiae: A new strategy for the wine fermentation process.}, journal = {Food microbiology}, volume = {117}, number = {}, pages = {104386}, doi = {10.1016/j.fm.2023.104386}, pmid = {37919010}, issn = {1095-9998}, abstract = {Bacterial biofilms have attracted much attention in the food industry since this phenotype increases microbial resistance to environmental stresses. In wine-making, the biofilm produced by Oenococcus oeni is able to persist in this harsh environment and perform malolactic fermentations. Certain viticultural practices are interested in the simultaneous triggering of alcoholic fermentation by yeasts of the species Saccharomyces cerevisiae and malolactic fermentation by lactic acid bacteria. As yet, no data is available on the ability of these micro-organisms to produce mixed biofilms and promote fermentations. Here, the ability of S. cerevisiae and O. oeni to form mixed biofilms on different surfaces found in vinification was observed and analyzed using scanning electron microscopy experiments. Then, following co-inoculation with biofilm or planktonic cells microvinifications were carried out to demonstrate that the mixed biofilms developed on oak allow the efficient completion of fermentations because of their high resistance to stress. Finally, comparisons of the different metabolic profiles obtained by LC-MS were made to assess the impact of the mode of life of biofilms on wine composition.}, } @article {pmid37918997, year = {2024}, author = {Chaves, RD and Kumazawa, SH and Khaneghah, AM and Alvarenga, VO and Hungaro, HM and Sant'Ana, AS}, title = {Comparing the susceptibility to sanitizers, biofilm-forming ability, and biofilm resistance to quaternary ammonium and chlorine dioxide of 43 Salmonella enterica and Listeria monocytogenes strains.}, journal = {Food microbiology}, volume = {117}, number = {}, pages = {104380}, doi = {10.1016/j.fm.2023.104380}, pmid = {37918997}, issn = {1095-9998}, abstract = {This study determined the susceptibility to sanitizers and biofilm-forming ability on stainless steel of 43 Salmonella enterica and Listeria monocytogenes strains. Besides, the biofilm resistance to sanitizers of four bacterial pathogen strains was evaluated. Four sanitizers commonly used in the food industry were tested: peracetic acid (PAA), chlorine dioxide (ClO2), sodium hypochlorite (SH), and quaternary ammonium compound (QAC). The susceptibility to sanitizers varied widely among the strains of both pathogens. On the other hand, the number of biofilm-associated cells on the stainless-steel surface was >5 log CFU/cm[2] for all of them. Only one Salmonella strain and two L. monocytogenes strains stood out as the least biofilm-forming. The resistance of biofilms to sanitizers also varied among strains of each pathogen. Biofilms of L. monocytogenes were more susceptible to the disinfection process with ClO2 and QAC than those of Salmonella. However, no correlation was observed between the ability to form denser biofilm and increased sanitizer resistance. In general, chlorine compounds were more effective than other sanitizers in inactivating planktonic cells and biofilms.}, } @article {pmid37917668, year = {2023}, author = {Yaeger, LN and French, S and Brown, ED and Côté, JP and Burrows, LL}, title = {Central metabolism is a key player in E. coli biofilm stimulation by sub-MIC antibiotics.}, journal = {PLoS genetics}, volume = {19}, number = {11}, pages = {e1011013}, doi = {10.1371/journal.pgen.1011013}, pmid = {37917668}, issn = {1553-7404}, abstract = {Exposure of Escherichia coli to sub-inhibitory antibiotics stimulates biofilm formation through poorly characterized mechanisms. Using a high-throughput Congo Red binding assay to report on biofilm matrix production, we screened ~4000 E. coli K12 deletion mutants for deficiencies in this biofilm stimulation response. We screened using three different antibiotics to identify core components of the biofilm stimulation response. Mutants lacking acnA, nuoE, or lpdA failed to respond to sub-MIC cefixime and novobiocin, implicating central metabolism and aerobic respiration in biofilm stimulation. These genes are members of the ArcA/B regulon-controlled by a respiration-sensitive two-component system. Mutants of arcA and arcB had a 'pre-activated' phenotype, where biofilm formation was already high relative to wild type in vehicle control conditions, and failed to increase further with the addition of sub-MIC cefixime. Using a tetrazolium dye and an in vivo NADH sensor, we showed spatial co-localization of increased metabolic activity with sub-lethal concentrations of the bactericidal antibiotics cefixime and novobiocin. Supporting a role for respiratory stress, the biofilm stimulation response to cefixime and novobiocin was inhibited when nitrate was provided as an alternative electron acceptor. Deletion of a gene encoding part of the machinery for respiring nitrate abolished its ameliorating effects, and nitrate respiration increased during growth with sub-MIC cefixime. Finally, in probing the generalizability of biofilm stimulation, we found that the stimulation response to translation inhibitors, unlike other antibiotic classes, was minimally affected by nitrate supplementation, suggesting that targeting the ribosome stimulates biofilm formation in distinct ways. By characterizing the biofilm stimulation response to sub-MIC antibiotics at a systems level, we identified multiple avenues for design of therapeutics that impair bacterial stress management.}, } @article {pmid37915709, year = {2023}, author = {Liu, R and Zhai, L and Feng, S and Gao, R and Zheng, J}, title = {Research frontiers and hotspots in bacterial biofilm wound therapy: bibliometric and visual analysis for 2012-2022.}, journal = {Annals of medicine and surgery (2012)}, volume = {85}, number = {11}, pages = {5538-5549}, pmid = {37915709}, issn = {2049-0801}, abstract = {BACKGROUND: Bacterial biofilms, which can protect bacteria from host immune response and drug attack, are an important factor in the difficult healing of chronic wound infection, which has become a major problem in medical development. This paper aimed to analyze literature related to bacterial biofilm wound treatment published between 2012 and 2022 using bibliometric and visual analysis.

METHODS: Publications related to bacterial biofilm wound treatment from 2012 to 2022 were selected from the Web of Science Core Collection. Microsoft Excel 2021, bibliometrics, CiteSpace6.1, and VOSviewer1.6.18 were used to extract and analyze data.

RESULTS: A total of 940 articles were published between 2012 and 2022, with the United States being the leading country (with 302 papers, 32.13%) and the University of Copenhagen in Denmark being the leading institution (with 26 published articles) in the field. Steven L Percival, a British academic, published the most articles (14). In the field of bacterial biofilm wound treatment, keywords suggested that the research gradually transitioned from lower limb venous ulcer, negative pressure-assisted healing to chronic wound, in-vitro bacterial biological model research, and then to the development of more microscopic and more advanced technologies such as antibacterial activity and nanomaterials. "Nanoparticles", "inhibition/antibacterial", "delivery", "gold nanoparticles", "hydrogel", "wound healing", etc., may become new research hotspots in this field.

CONCLUSION: There is a lack of specific and effective treatment methods for diagnosing and treating bacterial biofilms in wounds. Through the development of multidisciplinary cooperation, early diagnosis and treatment of bacterial biofilms in wounds can be achieved. These data may provide a useful reference for scholars studying more effective bacterial biofilm wound treatment.}, } @article {pmid37913826, year = {2023}, author = {Rather, MA and Mandal, M}, title = {Attenuation of biofilm and quorum sensing regulated virulence factors of an opportunistic pathogen Pseudomonas aeruginosa by phytofabricated silver nanoparticles.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106433}, doi = {10.1016/j.micpath.2023.106433}, pmid = {37913826}, issn = {1096-1208}, abstract = {Green-synthesized nanoparticles provide an effective strategy for inhibiting microbial pathogenesis by affecting biofilm formation, quorum sensing (QS), and other surface properties of microorganisms. QS is a density-dependent communication signaling cascade that regulates biofilm formation and pathogenic factors of Pseudomonas aeruginosa. In this context, the effect of phytofabricated silver nanoparticles (CC-AgNPs) synthesized using Cuphea carthagenensis extract on biofilm, QS, and QS-dependent virulence factors of P. aeruginosa were evaluated in this study. CC-AgNPs demonstrated significant attenuation of biofilm, QS, and QS-dependent virulence factors at sub-MICs. A significant inhibition of 88.39 ± 4.32 %, 79.64 ± 3.31 %, 73.07 ± 3.0 %, and 61.67 ± 1.5 % of biofilm formation, quorum sensing, pyocyanin, and LasB elastase, respectively was reported in the study at 20 μg/mL. The study also demonstrated a significant reduction of LasA Staphylolytic activity and 91.37 ± 1.05 % exoprotease production in comparison to untreated control. The lower concentrations of CC-AgNPs also demonstrated significant attenuation of biofilm and other virulence factors suggesting the strong potency of NPs against P. aeruginosa. XTT analysis reported the effect of CC-AgNPs on sessile cells of P. aeruginosa without impacting growth of planktonic cells at sub-MICs. Cell-proliferation study in human cell lines (HEK 293 and Caco-2 cells) demonstrated the safe nature of CC-AgNPs at tested concentrations. The study is novel in a way that environmentally friendly CC-AgNPs were used to inhibit QS at sub-MICs without killing the tested strains, therefore, could be developed as an anti-virulent drug to overcome biofilm and antimicrobial resistance problems.}, } @article {pmid37910305, year = {2023}, author = {Okolo, EA and de Alencar, ER and Machado, SG and Faroni, LRD and Silva, MVA and Costa, NADS and Falqueto, A}, title = {Ozonation for Pseudomonas paracarnis control: biofilm removal and preservation of chicken meat during refrigerated storage.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37910305}, issn = {1678-4405}, support = {405894/2021-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; APQ-01701-22//Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; APQ-00088-21//Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; Funding Code 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {Ozone has been studied to control microorganisms in food, as well as to control biofilm. In this context, the goals of this work were to determine the effect of ozonated water in the removal of Pseudomonas paracarnis biofilm and the effect of ozone gas and ozonated water on inactivating P. paracarnis in deboned chicken breast meat and its effect on product color. AISI 304 coupons were used as a surface for biofilm formation. The coupons were immerged into minimal medium for Pseudomonas inoculated with the P. paracarnis overnight culture (1% w/v) followed by incubation at 25 °C for 7 days. To obtain ozonized water, two different systems were used: system with microbubble generator (MB) and system with porous stone diffuser (PSD). The inlet ozone concentration was 19 mg/L and flow rate of 1 L/min. The coupons were subjected to ozonized water for 10 and 20 min. The chicken breast meat was exposed to gaseous ozone and ozonized water for 40 min. After the ozonation process, chicken meat samples were stored at 8 °C, for 5 days. More expressive removals of biofilm were obtained when using ozonized water obtained in the system with microbubble generator (MB for 20 min-reduction of 2.3 log cycles) and system with porous stone diffuser (PSD for 10 min-reduction of 2.7 log cycles; PSD for 20 min-reduction of 2.6 log cycles). The treatment of chicken meat with ozone gas resulted in lower counting of Pseudomonas, when compared with the control treatments and with ozonized water, both immediately after ozonation (day 1) and after 5 days of storage. The luminosity in the chicken meat samples treated with ozonized water was higher than that verified in the control treatments and with ozone gas, immediately after ozonation (day 1). A similar trend was observed in hue angle and color difference, in which the highest values were obtained for treatment with ozonized water. Based on the results obtained in this study, it was concluded that ozonated water can be used to remove P. paracarnis biofilm from stainless steel under static conditions and gaseous ozone is more efficient in the inactivation of P. paracarnis from chicken breast meat, when compared to ozonated water.}, } @article {pmid37910015, year = {2023}, author = {Pourhajibagher, M and Azimi Mohammadabadi, M and Ghafari, HA and Hodjat, M and Bahador, A}, title = {Evaluation of anti-biofilm effect of antimicrobial sonodynamic therapy-based periodontal ligament stem cell-derived exosome-loaded kojic acid on Enterococcus faecalis biofilm.}, journal = {Journal of medical microbiology}, volume = {72}, number = {11}, pages = {}, doi = {10.1099/jmm.0.001772}, pmid = {37910015}, issn = {1473-5644}, abstract = {Introduction. Antimicrobial sonodynamic therapy (aSDT) is an approach that uses ultrasound waves (UWs) and a sonosensitizer to generate reactive oxygen species (ROS) to damage microbial cells in biofilms. Using nano-carriers, such as exosomes (Exos), to deliver the sonosensitizer can potentially enhance the effectiveness of aSDT.Hypothesis/Gap Statement. aSDT can downregulate the expression of gelE and sprE genes, increasing the production of endogenous ROS and degradation of pre-formed Enterococcus faecalis biofilms.Aim. This study investigated the anti-biofilm effect of aSDT-based periodontal ligament stem cell-derived exosome-loaded kojic acid (KA@PDL-Exo) on pre-formed E. faecalis biofilms in root canals.Methodology. Following the isolation and characterization of PDL-Exo, KA@PDL-Exo was prepared and confirmed. The minimal biofilm inhibitory concentration (MBIC) of KA, PDL-Exo, KA@PDL-Exo and sodium hypochlorite (NaOCl) was determined, and their anti-biofilm effects were assessed with and without UWs. The binding affinity of KA with GelE and SprE proteins was evaluated using in silico molecular docking. Additionally, the study measured the generation of endogenous ROS and evaluated changes in the gene expression levels of gelE and sprE.Results. The results revealed a dose-dependent decrease in the viability of E. faecalis cells within biofilms. KA@PDL-Exo was the most effective, with an MBIC of 62.5 µg ml[-1], while NaOCl, KA and PDL-Exo had MBIC values of 125, 250 and 500 µg ml[-1], respectively. The use of KA@PDL-Exo-mediated aSDT resulted in a significant reduction of the E. faecalis biofilm (3.22±0.36 log10 c.f.u. ml[-1]; P<0.05). The molecular docking analysis revealed docking scores of -5.3 and -5.2 kcal mol[-1] for GelE-KA an SprE-KA, respectively. The findings observed the most significant reduction in gene expression of gelE and sprE in the KA@PDL-Exo group, with a decrease of 7.9- and 9.3-fold, respectively, compared to the control group (P<0.05).Conclusion. The KA@PDL-Exo-mediated aSDT was able to significantly reduce the E. faecalis load in pre-formed biofilms, decrease the expression of gelE and srpE mRNA, and increase the generation of endogenous ROS. These findings imply that KA@PDL-Exo-mediated aSDT could be a promising anti-biofilm strategy that requires additional in vitro and in vivo investigations.}, } @article {pmid37909474, year = {2023}, author = {Prüßner, T and Meinderink, D and Zhu, S and Orive, AG and Kielar, C and Huck, M and Steinrück, HG and Keller, A and Grundmeier, G}, title = {Molecular Adhesion of a Pilus-derived Peptide Involved in Pseudomonas aeruginosa Biofilm Formation on non-polar ZnO Surfaces.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e202302464}, doi = {10.1002/chem.202302464}, pmid = {37909474}, issn = {1521-3765}, abstract = {Bacterial colonization and biofilm formation on abiotic surfaces are initiated by the adhesion of peptides and proteins. Understanding the adhesion of such peptides and proteins at a molecular level thus represents an important step toward controlling and suppressing biofilm formation on technological and medical materials. This study investigates the molecular adhesion of a pilus-derived peptide that facilitates biofilm formation of Pseudomonas aeruginosa, a multidrug-resistant opportunistic pathogen frequently encountered in healthcare settings. Single-molecule force spectroscopy (SMFS) was performed on chemically etched ZnO surfaces to gather insights about peptide adsorption force and its kinetics. Metal-free click chemistry for the fabrication of peptide-terminated SMFS cantilevers was performed on amine-terminated gold cantilevers and verified by X-ray photoelectron spectroscopy (XPS) and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). Atomic force microscopy (AFM) and XPS analyses reveal stable topographies and surface chemistries of the substrates that are not affected by SMFS. Rupture events described by the worm-like chain model (WLC) up to 600 pN were detected for the non-polar ZnO(11-20) surfaces. The dissociation barrier energy at zero force ΔG(0), the transition state distance xb and bound-unbound dissociation rate at zero force koff(0) for the single crystalline substrate indicate that coordination and hydrogen bonds dominate the peptide/surface interaction.}, } @article {pmid37909408, year = {2023}, author = {Zheng, Y and Song, H and Chen, Q and Hou, Y and Zhang, X and Han, S}, title = {Comparing biofilm reactors inoculated with Shewanella for decolorization of Reactive Black 5 using different carrier materials.}, journal = {Biotechnology journal}, volume = {}, number = {}, pages = {e2300299}, doi = {10.1002/biot.202300299}, pmid = {37909408}, issn = {1860-7314}, abstract = {This study assessed the performance of biofilm reactors inoculated with azo dye degrading Shewanella for the decolorization of Reactive Black 5 (RB5), using three different carrier materials, namely almond shell biochar, moving bed biofilm reactor (MBBR), and polypropylene carrier (PPC). The reactors were fed with low-nutrient artificial wastewater containing RB5, and all three carriers showed good RB5 decolorization performance, with varying efficiencies. Liquid Chromatography-Mass Spectrometry analysis revealed distinct RB5 degradation pathways associated with each carrier, influenced by carrier materials and microbial communities. The MBBR carrier exhibited good stability due to its rough surface and microbial aggregates. Sequencing results highlighted differences in the microbial community structures among the carriers. Shewanella predominated the functional bacteria in the MBBR and PPC carriers, while the biochar carrier fostered highly efficient degrading microbial communities. The physicochemical properties of carrier materials significantly influenced the microbial community and RB5 degradation efficiency. These findings provide valuable insights for optimizing biofilm reactors for dye-containing wastewater treatment. This article is protected by copyright. All rights reserved.}, } @article {pmid37908782, year = {2023}, author = {Clavijo-Giraldo, DM and Pérez-García, LA and Hernández-Chávez, MJ and Martínez-Duncker, I and Mora-Montes, HM}, title = {Contribution of N-Linked Mannosylation Pathway to Candida parapsilosis and Candida tropicalis Biofilm Formation.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {6843-6857}, pmid = {37908782}, issn = {1178-6973}, abstract = {BACKGROUND: Mycoses are a growing threat to human health, and systemic candidiasis caused by Candida parapsilosis and Candida tropicalis is frequent in immunocompromised patients. Biofilm formation is a virulence factor found in these organisms, as sessile cells adhere to surfaces, the stratification and production of extracellular matrix provides protection and resistance to antifungal drugs. Previous evidence indicated that the N-linked mannosylation pathway is relevant to C. albicans biofilms, but its contribution to other species remains unknown.

METHODS: C. parapsilosis and C. tropicalis och1∆ mutants, which have a disrupted N-linked mannosylation pathway, were used to form biofilms. In addition, wild-type and mutant cells were also treated to remove N-linked mannans or block this pathway. Biofilms were analyzed by quantifying the included fungal biomass, and extracellular matrix components. Moreover, gene expression and secreted hydrolytic enzymes were also quantified in these biofilms.

RESULTS: The och1∆ mutants showed a reduced ability to form biofilms in both fungal species when compared to the wild-type and control strains. This observation was confirmed by trimming N-linked mannans from walls or blocking the pathway with tunicamycin B. According to this observation, mutant, and treated cells showed an altered composition of the extracellular matrix and increased susceptibility to antifungal drugs when compared to control or untreated cells. The gene expression of secreted virulence factors, such as aspartyl proteinases and phospholipases, was normal in all the tested cells but the secreted activity was reduced, suggesting a defect in the secretory pathway, which was later confirmed by treating cells with brefeldin A.

CONCLUSION: Proper N-linked mannosylation is required for biofilm formation in both C. parapsilosis and C. tropicalis. Disruption of this posttranslational modification affected the secretory pathway, offering a link between glycosylation and biofilm formation.}, } @article {pmid37907168, year = {2023}, author = {Egbadon, EO and Wigley, K and Nwoba, ST and Carere, CR and Weaver, L and Baronian, K and Burbery, L and Gostomski, PA}, title = {Microaerobic methane-driven denitrification in a biotrickle bed - Investigating the active microbial biofilm community composition using RNA-stable isotope probing.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140528}, doi = {10.1016/j.chemosphere.2023.140528}, pmid = {37907168}, issn = {1879-1298}, abstract = {A microaerobic (2% O2 v/v) biotrickle bed reactor supplied continuously with 2% methane to drive nitrate removal (MAME-D) was investigated using 16S rDNA and rRNA amplicon sequencing in combination with RNA-stable isotope probing (RNA-SIP) to identify the active microorganisms. Methane removal rates varied from 500 to 1000 mmol m[-3]h[-1] and nitrate removal rates from 25 to 58 mmol m[-3]h[-1] over 55 days of operation. Biofilm samples from the column were incubated in serum bottles supplemented with [13]CH4. 16S rDNA analysis indicated a simple community structure in which four taxa accounted for 45% of the total relative abundance (RA). Dominant genera included the methanotroph Methylosinus and known denitrifiers Nubsella and Pseudoxanthomonas; along with a probable denitrifier assigned to the order Obscuribacterales. The 16S rRNA results revealed the methanotrophs Methylocystis (15% RA) and Methylosinus (10% RA) and the denitrifiers Arenimonas (10% RA) and Pseudoxanthomonas (7% RA) were the most active genera. Obscuribacterales was the most active taxa in the community at 22% RA. Activity was confirmed by the Δ buoyant density changes with time for the taxa, indicating most of the community activity was associated with methane oxidation and subsequent consumption of methanotrophic metabolic intermediates by the denitrifiers. This is the first report of RNA stable isotope probing within a microaerobic methane driven denitrification system and the active community was markedly different from the full community identified via 16S-rDNA analysis.}, } @article {pmid37903473, year = {2023}, author = {Zhou, M and Liu, Y and Xu, H and Chen, X and Zheng, N and Duan, Z and Ge, Y and Li, D and Lin, T and Zeng, R and Chen, Q and Li, M}, title = {YTHDC1-modified m6A methylation of hsa_circ_0102678 promotes keratinocyte inflammation induced by Cutibacterium acnes biofilm through regulating miR-146a/TRAF6 and IRAK1 axis.}, journal = {Journal of innate immunity}, volume = {}, number = {}, pages = {}, doi = {10.1159/000534704}, pmid = {37903473}, issn = {1662-8128}, abstract = {INTRODUCTION: CircRNAs are closely related to many human diseases, however, their role in acne remains unclear. This study aimed to determine the role of hsa-circ_0102678 in regulating inflammation of acne.

METHODS: Firstly, microarray analysis was performed to study the expression of circRNAs in acne. Subsequently, RNase R digestion assay and FISH assay were utilized to confirm the characteristics of hsa-circ_0102678. Finally, qRT-PCR, Western blotting analysis, Immunoprecipitation, Luciferase reporter assay, circRNA probe pull-down assay, Biotin-labeled miRNA pull-down assay, RNA immunoprecipitation (RIP) assay and m6A dot blot assay were utilized to reveal the functional roles of hsa-circ_0102678 on inflammation induced by C. acnes biofilm in human primary keratinocytes.

RESULTS: Our investigations showed that the expression of hsa-circ_0102678 was significantly decreased in acne tissues and hsa-circ_0102678 was a type of circRNAs, which was mainly localized in the cytoplasm of primary human keratinocytes. Moreover, hsa-circ_0102678 remarkably affected the expression of IL-8, IL-6, and TNF-α, which induced by C. acnes biofilm. Importantly, mechanistic studies indicated that the YTHDC1 could bind directly to hsa-circ_0102678 and promote the export of N6-methyladenosine modified hsa-circ_0102678 to the cytoplasm. Besides, hsa-circ_0102678 could bind to miR-146a and sponge miR-146a to promote the expression of IRAK1 and TRAF6.

CONCLUSION: Our findings revealed a previously unknown process by which hsa_circ_0102678 promoted keratinocyte inflammation induced by C. acnes biofilm via regulating miR-146a/TRAF6 and IRAK1 axis.}, } @article {pmid37903266, year = {2023}, author = {Arnaouteli, S and Bamford, NC and Brandani, GB and Morris, RJ and Schor, M and Carrington, JT and Hobley, L and van Aalten, DMF and Stanley-Wall, NR and MacPhee, CE}, title = {Lateral interactions govern self-assembly of the bacterial biofilm matrix protein BslA.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {45}, pages = {e2312022120}, doi = {10.1073/pnas.2312022120}, pmid = {37903266}, issn = {1091-6490}, support = {102400/Z/13/Z//Wellcome Trust (WT)/ ; 200208/Z/15/Z//Wellcome Trust (WT)/ ; BB/R012415/1//UKRI | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/P001335/1//UKRI | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/X002950/1//UKRI | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; ALTF 471-2020//European Molecular Biology Organization (EMBO)/ ; }, abstract = {The soil bacterium Bacillus subtilis is a model organism to investigate the formation of biofilms, the predominant form of microbial life. The secreted protein BslA self-assembles at the surface of the biofilm to give the B. subtilis biofilm its characteristic hydrophobicity. To understand the mechanism of BslA self-assembly at interfaces, here we built a molecular model based on the previous BslA crystal structure and the crystal structure of the BslA paralogue YweA that we determined. Our analysis revealed two conserved protein-protein interaction interfaces supporting BslA self-assembly into an infinite 2-dimensional lattice that fits previously determined transmission microscopy images. Molecular dynamics simulations and in vitro protein assays further support our model of BslA elastic film formation, while mutagenesis experiments highlight the importance of the identified interactions for biofilm structure. Based on this knowledge, YweA was engineered to form more stable elastic films and rescue biofilm structure in bslA deficient strains. These findings shed light on protein film assembly and will inform the development of BslA technologies which range from surface coatings to emulsions in fast-moving consumer goods.}, } @article {pmid37902212, year = {2023}, author = {Tange, Y and Murata, A and Yoshitake, S}, title = {Efficacy of combined disinfection with a nitric oxide donor in controlling biofilm formation on the reverse osmosis water pathway for hemodialysis.}, journal = {Journal of water and health}, volume = {21}, number = {10}, pages = {1591-1599}, doi = {10.2166/wh.2023.220}, pmid = {37902212}, issn = {1477-8920}, abstract = {The water treatment system for hemodialysis (HD) is used to treat multiple patients requiring HD simultaneously. This system requires a large amount of purified reverse osmosis (RO) water. However, a major drawback of this method is the formation of biofilms in dialysate pathways. The purpose of this study was to investigate the efficacy of NOC 18, a nitric oxide (NO) donor that can be used at neutral pH, in disinfecting the RO water pathway. Silicone tubes were obtained from the terminal sites of two different HD units. The biofilm coverage and mean biofilm thickness on the tube lumen were evaluated by scanning electron microscopy. The results demonstrated that treatment with NOC 18 alone and in conjunction with sodium hypochlorite reduced biofilm coverage and mean biofilm thickness. Thus, NO donor is a potential disinfectant that enhances bacterial dispersion from biofilms formed on the silicone tube lumen and reduces biofilm coverage and thickness on the RO water pathway at neutral pH. Furthermore, combined disinfection with the NO donor and sodium hypochlorite might enhance biofilmremoval efficacy in clinical practice.}, } @article {pmid37898785, year = {2023}, author = {Rosli, NA and Al-Maleki, AR and Loke, MF and Chua, EG and Alhoot, MA and Vadivelu, J}, title = {Polymorphism of virulence genes and biofilm associated with in vitro induced resistance to clarithromycin in Helicobacter pylori.}, journal = {Gut pathogens}, volume = {15}, number = {1}, pages = {52}, pmid = {37898785}, issn = {1757-4749}, support = {Fundamental Research Grant Scheme FRGS No. DP KPT FRGS/1/2020/SKK0/UM/02/20. Project No. (FP105-2020)//Ministry of Higher Education, Malaysia/ ; }, abstract = {BACKGROUND: Clarithromycin-containing triple therapy is commonly used to treat Helicobacter pylori infections. Clarithromycin resistance is the leading cause of H. pylori treatment failure. Understanding the specific mutations that occur in H. pylori strains that have evolved antibiotic resistance can help create a more effective and individualised antibiotic treatment plan. However, little is understood about the genetic reprogramming linked to clarithromycin exposure and the emergence of antibiotic resistance in H. pylori. Therefore, this study aims to identify compensatory mutations and biofilm formation associated with the development of clarithromycin resistance in H. pylori. Clarithromycin-sensitive H. pylori clinical isolates were induced to develop clarithromycin resistance through in vitro exposure to incrementally increasing concentration of the antibiotic. The genomes of the origin sensitive isolates (S), isogenic breakpoint (B), and resistant isolates (R) were sequenced. Single nucleotide variations (SNVs), and insertions or deletions (InDels) associated with the development of clarithromycin resistance were identified. Growth and biofilm production were also assessed.

RESULTS: The S isolates with A2143G mutation in the 23S rRNA gene were successfully induced to be resistant. According to the data, antibiotic exposure may alter the expression of certain genes, including those that code for the Cag4/Cag protein, the vacuolating cytotoxin domain-containing protein, the sel1 repeat family protein, and the rsmh gene, which may increase the risk of developing and enhances virulence in H. pylori. Enhanced biofilm formation was detected among R isolates compared to B and S isolates. Furthermore, high polymorphism was also detected among the genes associated with biofilm production.

CONCLUSIONS: Therefore, this study suggests that H. pylori may acquire virulence factors while also developing antibiotic resistance due to clarithromycin exposure.}, } @article {pmid37897999, year = {2023}, author = {Ke, Y and Sun, W and Liu, S and Zhu, Y and Yan, S and Chen, X and Xie, S}, title = {Seasonal variations of biofilm C, N and S cycling genes in a pilot-scale chlorinated drinking water distribution system.}, journal = {Water research}, volume = {247}, number = {}, pages = {120759}, doi = {10.1016/j.watres.2023.120759}, pmid = {37897999}, issn = {1879-2448}, abstract = {Biofilms in drinking water distribution systems (DWDS) host diverse microorganisms. However, the functional attributes of DWDS biofilms and their associations with seasonality remain unclear. This study aims to characterize variations in the microbial metabolic traits of DWDS biofilms collected during different seasons, using a pilot-scale DWDS in dark under plug-flow conditions during one-year operation period. Network analysis was used to predict the functional gene hosts. The overall functional attributes determined by shotgun metagenomics exhibited significant differences among seasons. Genes associated with aromatic metabolism, fatty acid biosynthesis and degradation, and capsular extracellular polymeric substance (EPS) were significantly upregulated in summer owing to the higher temperatures and chlorine in the influent of the DWDS. Moreover, the pathways associated with nitrogen, sulfur, glycolysis, and tricarboxylic acid (TCA) cycling, as well as carbon fixation were reconstructed and displayed according to the sampling season. Nitrogen reduction pathways [dissimilatory nitrate reduction to ammonium (DNRA) 73 %, assimilatory nitrate reduction to ammonium (ANRA) 21 %] were identified in DWDS biofilms, but nitrogen oxidation pathways were not. Sulfur cycling were involved in diverse pathways and genes. Glycolysis and TCA cycling offered electron donors and energy sources for nitrogen and sulfur reduction in biofilms. Carbon fixation was observed in DWDS biofilms, with the predominant pathway for fixing carbon dioxide being the reductive citrate cycle (38 %). Constructed functional gene networks composed of carbon, nitrogen, and sulfur cycling-related genes demonstrated synergistic effects (Positive proportion: 63.52-71.09 %). In addition, from spring to autumn, the network complexity decreased and network modularity increased. The assembly mechanism of carbon, nitrogen and sulfur cycling-related genes was driven by stochastic processes for all samples. These results highlight the diverse functional genes in DWDS biofilms, their synergetic interrelationships, and the seasonality effect on functional attributes.}, } @article {pmid37897998, year = {2023}, author = {Zhang, H and Gong, W and Xue, Y and Zeng, W and Bai, L and Li, G and Liang, H and Ng, HY}, title = {Simulated-sunlight enhances membrane aerated biofilm reactor performance in sulfamethoxazole removal and antibiotic resistance genes reduction.}, journal = {Water research}, volume = {247}, number = {}, pages = {120747}, doi = {10.1016/j.watres.2023.120747}, pmid = {37897998}, issn = {1879-2448}, abstract = {Membrane aerated biofilm reactors (MABRs) can be used to treat domestic wastewater containing sulfamethoxazole (SMX) because of their favorable performance in the treatment of refractory pollutants. However, biologics are generally subjected to antibiotics stress, which induces the production of antibiotic resistance genes (ARGs). In this study, a simulated-sunlight assisted MABR (L-MABR) was used to promote SMX removal and reduce ARGs production. The SMX removal efficiency of the l-MABR system was 9.62 % superior to that of the MABR system (83.13 %). In contrast from MABR, in the l-MABR, only 28.75 % of SMX was removed through microbial activity because functional bacteria were inactivated through radiation by simulated sunlight. In addition, photolysis (64.61 %) dominated SMX removal, and the best performing indirect photolysis process was the excited state of effluent organic matters ([3]EfOMs*). Through photolysis, ultraviolet (UV) and reactive oxygen species (ROS) enriched the SMX removal route, resulting in the SMX removal pathway in the l-MABR no longer being limited by enzyme catalysis. More importantly, because of the inactivation of functional bacteria, whether in the effluent or biofilm, the copy number of ARGs in the l-MABR was 1-3 orders of magnitude lower than that in the MABR. Our study demonstrates the feasibility of utilizing simulated-sunlight to enhance the antibiotic removal efficiency while reducing ARG production, thus providing a novel idea for the removal of antibiotics from wastewater.}, } @article {pmid37897997, year = {2023}, author = {Zhao, Y and Gao, J and Wang, Z and Zhang, Y and Zhao, M and Zhang, H and Yuan, Y}, title = {Successive exposure to traditional disinfectants and quaternary ammonium compounds enhances resistance genes expression and co-selection in biofilm-based partial nitrification-anammox systems.}, journal = {Water research}, volume = {247}, number = {}, pages = {120760}, doi = {10.1016/j.watres.2023.120760}, pmid = {37897997}, issn = {1879-2448}, abstract = {Quaternary ammonium compounds (QACs) are recommended disinfectants with surfactant properties, surpassing triclosan (TCS) and chloroxylenol (PCMX). Given the transition from traditional disinfectants, it is essential to investigate their impacts on biological nitrogen removal systems and the fate of resistance genes (RGs). In this study, three biofilm-based partial nitrification-anammox (PN/A) systems were established. A reactor named PD was successively exposed to 1 mg/L PCMX and 3 mg/L dioctadecyldimethylammonium chloride (DODMAC, a common QACs). A reactor named TD was successively exposed to 1 mg/L TCS and 3 mg/L DODMAC. A reactor named CD served as a control with only 3 mg/L DODMAC exposure. Results indicated that the total nitrogen removal performance of CD deteriorated markedly with DODMAC exposure compared to that of PD and TD. This phenomenon correlated closely with variations in RGs and their co-selection patterns. Pre-exposure to PCMX or TCS increased the abundance of RGs in the extracellular DNA of the PN/A biofilm, but reduced RGs abundances in the extracellular DNA of water. The tolerance of the PN/A system to successive exposure to the two disinfectants may be strengthened through co-selection of QACs RGs (qacEdelta1-01, qacEdelta1-02, qacH-01 and qacH-02) and mobile genetic elements (intI1 and tnpA-04). Furthermore, potential hosts of RGs are crucial for maintaining PN/A performance. Accumulation of extracellular polymeric substances, reactive oxygen species, and lactate dehydrogenase plays vital roles in the accumulation and transmission of RGs within the PN/A system.}, } @article {pmid37897992, year = {2023}, author = {Lu, Y and Liu, T and Niu, C and Duan, H and Zheng, M and Hu, S and Yuan, Z and Wang, H and Guo, J}, title = {Challenges of suppressing nitrite-oxidizing bacteria in membrane aerated biofilm reactors by low dissolved oxygen control.}, journal = {Water research}, volume = {247}, number = {}, pages = {120754}, doi = {10.1016/j.watres.2023.120754}, pmid = {37897992}, issn = {1879-2448}, abstract = {Membrane aerated biofilm reactor (MABR) and shortcut nitrogen removal are two types of solutions to reduce energy consumption in wastewater treatment, with the former improving the aeration efficiency and the latter reducing the oxygen demand. However, integrating these two solutions, i.e., achieving shortcut nitrogen removal in MABR, is challenging due to the difficulty in suppressing nitrite-oxidizing bacteria (NOB). In this study, four MABRs were established to demonstrate the feasibility of initiating, maintaining, and restoring NOB suppression using low dissolved oxygen (DO) control, in the presence and absence of anammox bacteria, respectively. Long-term results revealed that the strict low DO (< 0.1 mg/L) in MABR could initiate and maintain stable NOB suppression for more than five months with nitrite accumulation ratio above 90 %, but it was unable to re-suppress NOB once they prevailed. Moreover, the presence of anammox bacteria increased the threshold of DO level to maintain NOB suppression in MABRs, but it was still incapable to restore the deteriorated NOB suppression in conjunction with low DO control. Mathematical modelling confirmed the experimental results and further explored the differences of NOB suppression in conventional biofilms and MABR biofilms. Simulation results showed that it is more challenging to maintain stable NOB suppression in MABRs compared to conventional biofilms, regardless of biofilm thickness or influent nitrogen concentration. Kinetic mechanisms for NOB suppression in different types of biofilms were proposed, suggesting that it is difficult to wash out NOB developed in the innermost layer of MABR biofilms because of the high oxygen level and low sludge wasting rate. In summary, this study systematically demonstrated the challenges of NOB suppression in MABRs through both experiments and mathematical modelling. These findings provide valuable insights into the applications of MABRs and call for more studies in developing effective strategies to achieve stable shortcut nitrogen removal in this energy-efficient configuration.}, } @article {pmid37897909, year = {2023}, author = {Tang, Z and Feng, J and Rowthu, SR and Zou, C and Peng, H and Huang, C and He, Y}, title = {Uncovering the anti-biofilm activity of Ilicicolin B against Staphylococcus aureus.}, journal = {Biochemical and biophysical research communications}, volume = {684}, number = {}, pages = {149138}, doi = {10.1016/j.bbrc.2023.149138}, pmid = {37897909}, issn = {1090-2104}, abstract = {The formation of bacterial biofilms reduces the entry of antibiotics into bacteria and helps bacteria tolerate otherwise lethal concentrations of antimicrobials, leading to antibiotic resistance. Therefore, clearing bacterial biofilm is an effective strategy to tackle drug resistance. Currently, there are no approved antibiotics for inhibiting bacterial biofilm formation. We found that Ilicicolin B had excellent antibacterial activity against MRSA without obvious hemolytic activity. More importantly, Ilicicolin B effectively inhibited the biofilm formation in a concentration-dependent manner by crystal violet colorimetric assay and fluorescence microscopy analysis. Exposure of Staphylococcus aureus to Ilicicolin B for 24 h reduced the protein and polysaccharide components in EPS, suggesting that Ilicicolin B disintegrated the biofilms by dissociating the EPS in a matrix. In addition, Ilicicolin B demonstrated strong antibacterial effects in a murine abscess model of S. aureus. Our findings suggest that Ilicicolin B has the potential to treat S. aureus infection by inhibiting biofilm formation.}, } @article {pmid37897710, year = {2023}, author = {Hamed, SM and Mohamed, HO and Ashour, HM and Fahmy, LI}, title = {Comparative genomic analysis of strong biofilm-forming Klebsiella pneumoniae isolates uncovers novel ISEcp1-mediated chromosomal integration of a full plasmid-like sequence.}, journal = {Infectious diseases (London, England)}, volume = {}, number = {}, pages = {1-19}, doi = {10.1080/23744235.2023.2272624}, pmid = {37897710}, issn = {2374-4243}, abstract = {BACKGROUND: The goal of the current study was to elucidate the genomic background of biofilm formation in Klebsiella pneumoniae.

METHODS: Clinical isolates were screened for biofilm formation using the crystal violet assay. Antimicrobial resistance (AMR) profiles were assessed by disk diffusion and broth microdilution tests. Biofilm formation was correlated to virulence and resistance genes screened by PCR. Draft genomes of three isolates that form strong biofilm were generated by Illumina sequencing.

RESULTS: Only the siderophore-coding gene iutA was significantly associated with more pronounced biofilm formation. ST1399-KL43-O1/O2v1 and ST11-KL15-O4 were assigned to the multidrug-resistant strain K21 and the extensively drug-resistant strain K237, respectively. ST1999-KL38-O12 was assigned to K57. Correlated with CRISPR/Cas distribution, more plasmid replicons and prophage sequences were identified in K21 and K237 compared to K57. The acquired AMR genes (blaOXA-48, rmtF, aac(6')-Ib and qnrB) and (blaNDM-1, blaCTX-M, aph(3')-VI, qnrS, and aac(6')-Ib-cr) were found in K237 and K21, respectively. The latter showed a novel ISEcp1-mediated chromosomal integration of replicon type IncM1 plasmid-like structure harboring blaCTX-M-14 and aph(3')-VI that uniquely interrupted rcsC. The plasmid-mediated heavy metal resistance genes merACDEPRT and arsABCDR were spotted in K21, which also exclusively carried the acquired virulence genes mrkABCDF and the hypervirulence-associated genes iucABCD-iutA, and rmpA/A2. Pangenome analysis revealed NTUH-K2044 accessory genes most frequently shared with K21.

CONCLUSIONS: While less virulent to Galleria mellonella than ST1999 (K57), the strong biofilm former, multidrug-resistant, NDM-producer K. pneumoniae K21 (ST1399-KL43-O1/O2v1) carries a novel chromosomally integrated plasmid-like structure and hypervirulence-associated genes and represents a serious threat to countries in the area.}, } @article {pmid37897595, year = {2023}, author = {Çam, S and Badıllı, İ}, title = {The effect of NaCl, pH, and phosphate on biofilm formation and exopolysaccharide production by high biofilm producers of Bacillus strains.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {37897595}, issn = {1874-9356}, support = {22230//Harran University-Scientific Research Projects/ ; }, abstract = {Biofilm formation is an effective survival strategy of plant-associated microorganisms in hostile environments, so the application of biofilm-forming and exopolysaccharide (EPS)-producing beneficial microbes to plants has received more attention in recent years. This study examined the ability of biofilm and EPS production of Bacillus subtilis and Bacillus thuringiensis strains under different NaCl concentrations (0, 50, 100, 200, and 400 mmol/L), pH values (5.5, 6.5, 7.5, and 8.5), and phosphate levels (0, 25, 50, and 100 mmol/L at 0 and 400 mmol/L NaCl). B. subtilis BS2 and B. thuringiensis BS6/BS7 strains significantly increased biofilm formation in a similar pattern to EPS production under salt stress. B. subtilis BS2/BS3 enhanced biofilm production at slightly acidic pH with a lower EPS production but the other strains formed considerably more amount of biofilm and EPS at alkaline pH. Interestingly, higher levels of phosphate substantially decreased biofilm and EPS production at 0 mmol/L NaCl but increased biofilm formation at 400 mmol/L salt concentration. Overall, contrary to phosphate, salt and pH differently influenced biofilm and EPS production by Bacillus strains. EPS production contributed to biofilm formation to some extent under all the conditions tested. Some Bacillus strains produced more abundant biofilm under salt and pH stress, indicating their potential to form in vivo biofilms in rhizosphere and on plants, particularly under unfavorable conditions.}, } @article {pmid37897520, year = {2023}, author = {Mendes, SG and Combo, SI and Allain, T and Domingues, S and Buret, AG and Da Silva, GJ}, title = {Co-regulation of biofilm formation and antimicrobial resistance in Acinetobacter baumannii: from mechanisms to therapeutic strategies.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37897520}, issn = {1435-4373}, support = {2021.06289.BD//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {In recent years, multidrug-resistant Acinetobacter baumannii has emerged globally as a major threat to the healthcare system. It is now listed by the World Health Organization as a priority one for the need of new therapeutic agents. A. baumannii has the capacity to develop robust biofilms on biotic and abiotic surfaces. Biofilm development allows these bacteria to resist various environmental stressors, including antibiotics and lack of nutrients or water, which in turn allows the persistence of A. baumannii in the hospital environment and further outbreaks. Investigation into therapeutic alternatives that will act on both biofilm formation and antimicrobial resistance (AMR) is sorely needed. The aim of the present review is to critically discuss the various mechanisms by which AMR and biofilm formation may be co-regulated in A. baumannii in an attempt to shed light on paths towards novel therapeutic opportunities. After discussing the clinical importance of A. baumannii, this critical review highlights biofilm-formation genes that may be associated with the co-regulation of AMR. Particularly worthy of consideration are genes regulating the quorum sensing system AbaI/AbaR, AbOmpA (OmpA protein), Bap (biofilm-associated protein), the two-component regulatory system BfmRS, the PER-1 β-lactamase, EpsA, and PTK. Finally, this review discusses ongoing experimental therapeutic strategies to fight A. baumannii infections, namely vaccine development, quorum sensing interference, nanoparticles, metal ions, natural products, antimicrobial peptides, and phage therapy. A better understanding of the mechanisms that co-regulate biofilm formation and AMR will help identify new therapeutic targets, as combined approaches may confer synergistic benefits for effective and safer treatments.}, } @article {pmid37896186, year = {2023}, author = {Yathavan, B and Chhibber, T and Steinhauff, D and Pulsipher, A and Alt, JA and Ghandehari, H and Jafari, P}, title = {Matrix-Mediated Delivery of Silver Nanoparticles for Prevention of Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation in Chronic Rhinosinusitis.}, journal = {Pharmaceutics}, volume = {15}, number = {10}, pages = {}, pmid = {37896186}, issn = {1999-4923}, support = {NCATS UL 1TR002538//the Utah Clinical & Translational Science Institute/ ; //the Skaggs Graduate Research Fellowship awarded by the University of Utah, College of Pharmacy/ ; //Research Incentive Seed Grant awarded by the University of Utah School of Medicine/ ; UM1TR004409 and 1K12TR004413//National Center for Advancing Translational Sciences of the National Institutes of Health under Award/ ; }, abstract = {Chronic rhinosinusitis (CRS) is a chronic health condition affecting the sinonasal cavity. CRS-associated mucosal inflammation leads to sinonasal epithelial cell death and epithelial cell barrier disruption, which may result in recurrent bacterial infections and biofilm formation. For patients who fail medical management and elect endoscopic sinus surgery for disease control, bacterial biofilm formation is particularly detrimental, as it reduces the efficacy of surgical intervention. Effective treatments that prevent biofilm formation in post-operative patients in CRS are currently limited. To address this unmet need, we report the controlled release of silver nanoparticles (AgNps) with silk-elastinlike protein-based polymers (SELPs) to prevent bacterial biofilm formation in CRS. This polymeric network is liquid at room temperature and forms a hydrogel at body temperature, and is hence, capable of conforming to the sinonasal cavity upon administration. SELP hydrogels demonstrated sustained AgNp and silver ion release for the studied period of three days, potent in vitro antibacterial activity against Pseudomonas aeruginosa (**** p < 0.0001) and Staphylococcus aureus (**** p < 0.0001), two of the most commonly virulent bacterial strains observed in patients with post-operative CRS, and high cytocompatibility with human nasal epithelial cells. Antibacterial controlled release platform shows promise for treating patients suffering from prolonged sinonasal cavity infections due to biofilms.}, } @article {pmid37895854, year = {2023}, author = {Abdulkareem, AH and Alalwani, AK and Ahmed, MM and Al-Meani, SAL and Al-Janaby, MS and Al-Qaysi, AK and Edan, AI and Lahij, HF}, title = {Impact of Solidago virgaurea Extract on Biofilm Formation for ESBL-Pseudomonas aeruginosa: An In Vitro Model Study.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {10}, pages = {}, doi = {10.3390/ph16101383}, pmid = {37895854}, issn = {1424-8247}, abstract = {The increasing disparity between antimicrobial resistance (AMR) and the development of new antimicrobials continues to pose a significant global health concern. However, plant extracts have shown promise in combating this issue either through their inherent antimicrobial activity or by serving as potential reservoirs of effective antimicrobial compounds. These compounds have the ability to target pathogenic biofilms and inhibit the production of extended-spectrum β -lactamases (ESBLs). However, there is limited research available on the antibacterial properties of goldenrod extract. Thus, the objective of this study was to investigate the impact of S. virgaurea (SV) extract on the viability and ability to form biofilms of ESBL-Pseudomonas aeruginosa (P. aeruginosa). A cross-sectional study was conducted from August 2022 to March 2023. The broth microdilution method was employed to determine the minimum inhibitory concentration (MIC) of the (SV) extract. Subsequently, the minimum bactericidal concentration (MBC) was determined based on the MIC values obtained. The antibiotic susceptibility of bacteria was evaluated using the Kirby disk diffusion assay and an Antimicrobial Susceptibility Testing (AST) card in conjunction with the Vitek-2 compact system. Biofilm formation was evaluated using Congo red and a 96-well Elisa plate, while the presence of extended-spectrum β-lactamases (ESBLs) was estimated by measuring the reduction of nitrocefin at a wavelength of 390 nm. In addition, treatment of biofilm and ESBL activity with SV extract using 96-well Elisa plate and nitrocefin hydrolyzing, respectively. The resistance rates of P. aeruginosa isolates to the tested antibiotics were as follows: Levofloxacin 33%, Ciprofloxacin 40%, Amikacin 49%, Meropenem 50%, Cefepime 70%, Ceftazidime 75%, Cefotaxime 85%, Piperacillin-Tazobactam 90%, Amoxiclav 97%, Ampicillin 99%, Ceftriaxone 100%. The prevalence of MDR-P. aeruginosa, XDR-P. aeruginosa, PDR-P. aeruginosa and non-MDR-PA were 40% (n = 40), 7% (n = 7), 3% (n = 3) and 50% (n = 50), respectively. From the GC-MS results, it was observed that the presence of Octadecane, Clioquinol, Glycerol tricaprylate, hexadecanoic acid, cis-13-octadecenoic acid, oleic acid and Propanamide were the major components in the Solidago extract. In the determination of plant crude extracts, the values ranged between 0.25 and 64 mg/mL against bacteria. The resulting activity of the extract showed a significant statistical relationship at a p-value ≤ 0.01 against ESBL production and biofilm formation in P. aeruginosa. The S. virgaurea extract exhibited effectiveness in inhibiting biofilm formation and combating P. aeruginosa strains that produce extended-spectrum β-lactamases (ESBLs).}, } @article {pmid37895209, year = {2023}, author = {Cooper, A and Makkay, AM and Papke, RT}, title = {Archaeal Tubulin-like Proteins Modify Cell Shape in Haloferax volcanii during Early Biofilm Development.}, journal = {Genes}, volume = {14}, number = {10}, pages = {}, doi = {10.3390/genes14101861}, pmid = {37895209}, issn = {2073-4425}, support = {NNX15AM09G//NASA exobiology/ ; 80NSSC18K1533//NASA exobiology/ ; }, abstract = {Tubulin, an extensively studied self-assembling protein, forms filaments in eukaryotic cells that affect cell shape, among other functions. The model archaeon Haloferax volcanii uses two tubulin-like proteins (FtsZ1/FtsZ2) for cell division, similar to bacteria, but has an additional six related tubulins called CetZ. One of them, CetZ1, was shown to play a role in cell shape. Typically, discoid and rod shapes are observed in planktonic growth, but under biofilm formation conditions (i.e., attached to a substratum), H. volcanii can grow filamentously. Here, we show that the deletion mutants of all eight tubulin-like genes significantly impacted morphology when cells were allowed to form a biofilm. ΔftsZ1, ΔcetZ2, and ΔcetZ4-6 created longer, less round cells than the parental and a higher percentage of filaments. ΔcetZ1 and ΔcetZ3 were significantly rounder than the parental, and ΔftsZ2 generated larger, flat, amorphic cells. The results show all tubulin homologs affect morphology at most timepoints, which therefore suggests these genes indeed have a function.}, } @article {pmid37895003, year = {2023}, author = {Seredin, P and Goloshchapov, D and Kashkarov, V and Lukin, A and Peshkov, Y and Ippolitov, I and Ippolitov, Y and Litvinova, T and Vongsvivut, J and Chae, B and Freitas, RO}, title = {Changes in Dental Biofilm Proteins' Secondary Structure in Groups of People with Different Cariogenic Situations in the Oral Cavity and Using Medications by Means of Synchrotron FTIR-Microspectroscopy.}, journal = {International journal of molecular sciences}, volume = {24}, number = {20}, pages = {}, doi = {10.3390/ijms242015324}, pmid = {37895003}, issn = {1422-0067}, support = {23-15-00060//Russian Science Foundation/ ; }, abstract = {This work unveils the idea that the cariogenic status of the oral cavity (the presence of active caries lesions) can be predicted via a lineshape analysis of the infrared spectral signatures of the secondary structure of proteins in dental biofilms. These spectral signatures that work as natural markers also show strong sensitivity to the application in patients of a so-called modulator-a medicinal agent (a pelleted mineral complex with calcium glycerophosphate). For the first time, according to our knowledge, in terms of deconvolution of the complete spectral profile of the amide I and amide II bands, significant intra- and intergroup differences were determined in the secondary structure of proteins in the dental biofilm of patients with a healthy oral cavity and with a carious pathology. This allowed to conduct a mathematical assessment of the spectral shifts in proteins' secondary structure in connection with the cariogenic situation in the oral cavity and with an external modulation. It was shown that only for the component parallel β-strands in the amide profile of the biofilm, a statistically significant (p < 0.05) change in its percentage weight (composition) was registered in a cariogenic situation (presence of active caries lesions). Note that no significant differences were detected in a normal situation (control) and in the presence of a carious pathology before and after the application of the modulator. The change in the frequency and percentage weight of parallel β-strands in the spectra of dental biofilms proved to be the result of the presence of cariogenic mutans streptococci in the film as well as of the products of their metabolism-glucan polymers. We foresee that the results presented here can inherently provide the basis for the infrared spectral diagnosis of changes (shifts) in the oral microbiome driven by the development of the carious process in the oral cavity as well as for the choice of optimal therapeutic treatments of caries based on microbiome-directed prevention measures.}, } @article {pmid37894209, year = {2023}, author = {Chávez-Hernández, M and Ortiz-Álvarez, J and Morales-Jiménez, J and Villa-Tanaca, L and Hernández-Rodríguez, C}, title = {Phenotypic and Genomic Characterization of Streptomyces pakalii sp. nov., a Novel Species with Anti-Biofilm and Anti-Quorum Sensing Activity in ESKAPE Bacteria.}, journal = {Microorganisms}, volume = {11}, number = {10}, pages = {}, doi = {10.3390/microorganisms11102551}, pmid = {37894209}, issn = {2076-2607}, support = {SIP-20211032, 20220795, and 20231480//This work was supported by Secretaría de Investigación y Posgrado-IPN (SIP-20211032, 20220795, and 20231480)./ ; }, abstract = {The increasing number of infections caused by antimicrobial multi-resistant microorganisms has led to the search for new microorganisms capable of producing novel antibiotics. This work proposes Streptomyces pakalii sp. nov. as a new member of the Streptomycetaceae family. The strain ENCB-J15 was isolated from the jungle soil in Palenque National Park, Chiapas, Mexico. The strain formed pale brown, dry, tough, and buried colonies in the agar with no diffusible pigment in GAE (glucose-asparagine-yeast extract) medium. Scanning electron micrographs showed typical mycelium with long chains of smooth and oval-shaped spores (3-10 m). The strain grew in all of the International Streptomyces Project (ISP)'s media at 28-37 °C with a pH of 6-9 and 0-10% NaCl. S. pakalii ENCB-J15 assimilated diverse carbon as well as organic and inorganic nitrogen sources. The strain also exhibited significant inhibitory activity against the prodigiosin synthesis of Serratia marcescens and the inhibition of the formation and destruction of biofilms of ESKAPE strains of Acinetobacter baumannii and Klebsiella pneumoniae. The draft genome sequencing of ENCB-J15 revealed a 7.6 Mb genome with a high G + C content (71.6%), 6833 total genes, and 6746 genes encoding putative proteins. A total of 26 accessory clusters of proteins associated with carbon sources and amino acid catabolism, DNA modification, and the antibiotic biosynthetic process were annotated. The 16S rRNA gene phylogeny, core-proteome phylogenomic tree, and virtual genome fingerprints support that S. pakalii ENCB-J15 is a new species related to Streptomyces badius and Streptomyces globisporus. Similarly, its average nucleotide identity (ANI) (96.4%), average amino acid identity (AAI) (96.06%), and virtual DNA-DNA hybridization (67.3%) provide evidence to recognize it as a new species. Comparative genomics revealed that S. pakalli and its closest related species maintain a well-conserved genomic synteny. This work proposes Streptomyces pakalii sp. nov. as a novel species that expresses anti-biofilm and anti-quorum sensing activities.}, } @article {pmid37894183, year = {2023}, author = {Rubio-Mendoza, D and Martínez-Meléndez, A and Maldonado-Garza, HJ and Córdova-Fletes, C and Garza-González, E}, title = {Review of the Impact of Biofilm Formation on Recurrent Clostridioides difficile Infection.}, journal = {Microorganisms}, volume = {11}, number = {10}, pages = {}, doi = {10.3390/microorganisms11102525}, pmid = {37894183}, issn = {2076-2607}, abstract = {Clostridioides difficile infection (CDI) may recur in approximately 10-30% of patients, and the risk of recurrence increases with each successive recurrence, reaching up to 65%. C. difficile can form biofilm with approximately 20% of the bacterial genome expressed differently between biofilm and planktonic cells. Biofilm plays several roles that may favor recurrence; for example, it may act as a reservoir of spores, protect the vegetative cells from the activity of antibiotics, and favor the formation of persistent cells. Moreover, the expression of several virulence genes, including TcdA and TcdB toxins, has been associated with recurrence. Several systems and structures associated with adhesion and biofilm formation have been studied in C. difficile, including cell-wall proteins, quorum sensing (including LuxS and Agr), Cyclic di-GMP, type IV pili, and flagella. Most antibiotics recommended for the treatment of CDI do not have activity on spores and do not eliminate biofilm. Therapeutic failure in R-CDI has been associated with the inadequate concentration of drugs in the intestinal tract and the antibiotic resistance of a biofilm. This makes it challenging to eradicate C. difficile in the intestine, complicating antibacterial therapies and allowing non-eliminated spores to remain in the biofilm, increasing the risk of recurrence. In this review, we examine the role of biofilm on recurrence and the challenges of treating CDI when the bacteria form a biofilm.}, } @article {pmid37894034, year = {2023}, author = {Kim, SY and Kim, M and Kim, TJ}, title = {Regulation of σ[B]-Dependent Biofilm Formation in Staphylococcus aureus through Strain-Specific Signaling Induced by Diosgenin.}, journal = {Microorganisms}, volume = {11}, number = {10}, pages = {}, doi = {10.3390/microorganisms11102376}, pmid = {37894034}, issn = {2076-2607}, support = {2021R1F1A1061888//National Research Foundation of Korea/ ; }, abstract = {Staphylococcus aureus is a commensal skin bacterium and a causative agent of infectious diseases. Biofilm formation in S. aureus is a mechanism that facilitates the emergence of resistant strains. This study proposes a mechanism for the regulation of biofilm formation in S. aureus through strain-specific physiological changes induced by the plant steroid diosgenin. A comparison of diosgenin-induced changes in the expression of regulatory genes associated with physiological changes revealed the intracellular regulatory mechanisms involved in biofilm formation. Diosgenin reduced biofilm formation in S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) CCARM 3090 by 39% and 61%, respectively. Conversely, it increased biofilm formation in S. aureus ATCC 29213 and MRSA CCARM 3820 by 186% and 582%, respectively. Cell surface hydrophobicity and extracellular protein and carbohydrate contents changed in a strain-specific manner in response to biofilm formation. An assessment of the changes in gene expression associated with biofilm formation revealed that diosgenin treatment decreased the expression of icaA and spa and increased the expression of RNAIII, agrA, sarA, and sigB in S. aureus ATCC 6538 and MRSA CCARM 3090; however, contrasting gene expression changes were noted in S. aureus ATCC 29213 and MRSA CCARM 3820. These results suggest that a regulatory mechanism of biofilm formation is that activated sigB expression sequentially increases the expression of sarA, agrA, and RNAIII. This increased RNAIII expression decreases the expression of spa, a surface-associated adhesion factor. An additional regulatory mechanism of biofilm formation is that activated sigB expression decreases the expression of an unknown regulator that increases the expression of icaA. This in turn decreases the expression of icaA, which decreases the synthesis of polysaccharide intercellular adhesins and ultimately inhibits biofilm formation. By assessing strain-specific contrasting regulatory signals induced by diosgenin in S. aureus without gene mutation, this study elucidated the signal transduction mechanisms that regulate biofilm formation based on physiological and gene expression changes.}, } @article {pmid37892914, year = {2023}, author = {Park, HM and Ryu, S and Jo, E and Yoo, SK and Kim, YW}, title = {A Study on the Biofilm Removal Efficacy of a Bioelectric Toothbrush.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, doi = {10.3390/bioengineering10101184}, pmid = {37892914}, issn = {2306-5354}, support = {S3301078//Ministry of SMEs and Startups (MSS, Korea)/ ; }, abstract = {Effective oral care is a critical requirement to maintain a high quality of life. Most oral diseases are caused by plaque (oral biofilm), which is also correlated with systemic diseases. A common method to remove biofilm is brushing teeth with toothpaste. However, 3.5 billion people in the world have oral diseases, meaning that more efficient methods of removing biofilms are needed. We have developed a toothbrush that applies a bioelectric effect (BE) utilizing an electric force for biofilm removal. It demonstrated significantly higher biofilm removal efficiency than non-BE manual toothbrushes. Tests were performed in saline and toothpaste conditions using various pressures. Results showed that the BE toothbrush had a significantly higher biofilm removal efficiency in saline (0.5 N: 215.43 ± 89.92%, 2.5 N: 116.77 ± 47.02%) and in a toothpaste slurry (0.5 N: 104.96 ± 98.93%, 2.5 N: 96.23 ± 35.16%) than non-BE manual toothbrushes. Results also showed that BE toothbrushes were less dependent on toothpaste. This study suggests that the application of BE can be a new solution to plaque problems in oral care.}, } @article {pmid37892873, year = {2023}, author = {Choi, SR and Kwon, JW and Suk, KS and Kim, HS and Moon, SH and Park, SY and Moon, SE and Lee, BH}, title = {Effectiveness of Toothbrushing Technique for Biofilm Removal and Postoperative Infection Control after Spinal Fusion Surgery: A Retrospective Study.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, doi = {10.3390/bioengineering10101143}, pmid = {37892873}, issn = {2306-5354}, abstract = {This retrospective study was designed to investigate the effectiveness of using a toothbrush, which is commonly used in our daily life, for biofilm removal and infection control in the treatment of spinal infections occurring after spinal fusion surgery. Currently, a biofilm is thought to form on the surface of the metal inserted during spine fusion surgery. We aim to determine the differences in clinical outcomes between using and not using a toothbrush to remove biofilm while performing conventional drainage, curettage, and debridement. A total of 1081 patients who underwent anterior or posterior spinal fusion surgery between November 2018 and October 2022 were screened. The study included 60 patients who developed surgical site infection and underwent incision and drainage surgery either with a toothbrush (n = 20) or without a toothbrush (n = 40). Failure of infection control that requires revision surgery occurred in 2 patients (10%) in the Toothbrush group and in 14 patients (35%) in the No-Toothbrush group (p = 0.039). Thus, the rate of additional surgery was significantly lower in the Toothbrush group. Additionally, normalization of c-reactive protein levels occurred significantly faster in the Toothbrush group (p = 0.044). Therefore, using a toothbrush to treat spinal infections following spinal fusion surgery appears to have beneficial mechanical debridement effects, resulting in improved clinical results, which were also confirmed based on the electron microscopic images.}, } @article {pmid37891945, year = {2023}, author = {Hidalgo, A and Bravo, D and Soto, C and Maturana, G and Cordero-Machuca, J and Zúñiga-López, MC and Oyarzun-Ampuero, F and Quest, AFG}, title = {The Anti-Oxidant Curcumin Solubilized as Oil-in-Water Nanoemulsions or Chitosan Nanocapsules Effectively Reduces Helicobacter pylori Growth, Bacterial Biofilm Formation, Gastric Cell Adhesion and Internalization.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {12}, number = {10}, pages = {}, doi = {10.3390/antiox12101866}, pmid = {37891945}, issn = {2076-3921}, support = {15130011//FONDAP/ ; 1170925, 1210644, 1201899, 1200877//FONDECYT/ ; }, abstract = {The bacterium Helicobacter pylori (H. pylori) represents a major risk factor associated with the development of gastric cancer. The anti-oxidant curcumin has been ascribed many benefits to human health, including bactericidal effects. However, these effects are poorly reproducible because the molecule is extremely unstable and water insoluble. Here we solubilized curcumin as either nanoemulsions or chitosan nanocapsules and tested the effects on H. pylori. The nanoemulsions were on average 200 nm in diameter with a PdI ≤ 0.16 and a negative zeta potential (-54 mV), while the nanocapsules were 305 nm in diameter with a PdI ≤ 0.29 and a positive zeta potential (+68 mV). Nanocapsules were safer than nanoemulsions when testing effects on the viability of GES-1 gastric cells. Also, nanocapsules were more efficient than nanoemulsions at inhibiting H. pylori growth (minimal inhibitory concentration: 50 and 75 μM, respectively), whereby chitosan contributed to this activity. Importantly, both formulations effectively diminished H. pylori's adherence to and internalization by GES-1 cells, as well as biofilm formation. In summary, the demonstrated activity of the curcumin nanoformulations described here against H. pylori posit them as having great potential to treat or complement other therapies currently in use against H. pylori infection.}, } @article {pmid37890740, year = {2023}, author = {Divakaran, D and Suyambulingam, I and Sanjay, MR and Raghunathan, V and Ayyappan, V and Siengchin, S}, title = {Isolation and characterization of microcrystalline cellulose from an agro-waste tamarind (Tamarindus indica) seeds and its suitability investigation for biofilm formulation.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127687}, doi = {10.1016/j.ijbiomac.2023.127687}, pmid = {37890740}, issn = {1879-0003}, abstract = {The exploration of potential bio-fillers for bio-film application is a promising approach to ensure biodegradable, eco-friendly, good-quality materials with high-performance applications. This is a comprehensive study executed to establish the utility of an agro-waste Tamarindus indica seeds for microcrystalline cellulose production and to assess its feasibility for biofilm fabrication. The extraction was carried out through consecutive chemical-mediated alkalization, acid hydrolysis and bleaching. The isolated microcrystalline cellulose from Tamarindus indica seeds (TSMCC) was characterized through chemical, thermal and morphological characterization to validate the cellulose contribution, thermal resistance, and compatibility of the material. The physical parameters as density and yield percentage were assessed to evaluate its light-weight utility and economic productivity. These examinations revealed that TSMCC has good specific properties such as high cellulose content (90.57 %), average density (1.561 g/cm[3]), feasible average roughness (12.161 nm), desired particle size (60.40 ± 21.10 μm), good crystallinity (CI-77.6 %) and thermal stability (up to 230 °C); which are worthwhile to consider TSMCC for bio-film formulation. Subsequently, bio-films were formulated by reinforcing TSMCC in polylactic acid (PLA) matrix and the mechanical properties of the bio-films were then studied to establish the efficacy of TSMCC. It is revealed that the properties of pure PLA film increased after being incorporated with TSMCC, where 5 %TSMCC addition showed greater impact on crystalline index (26.16 % to 39.62 %), thermal stability (333[o]c to 389 °C), tensile strength (36.11 ± 2.90 MPa to 40.22 ± 3.22 MPa) and modulus (2.62 ± 0.55GPa to 4.15 ± 0.53GPa). In light of all promising features, 5 % TSMCC is recommended as a potential filler reinforcement for the groundwork of good quality bio-films for active packaging applications in future.}, } @article {pmid37890634, year = {2023}, author = {Uri-Carreño, N and Nielsen, PH and Gernaey, KV and Domingo-Félez, C and Flores-Alsina, X}, title = {Nitrous oxide emissions from two full-scale membrane-aerated biofilm reactors.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {168030}, doi = {10.1016/j.scitotenv.2023.168030}, pmid = {37890634}, issn = {1879-1026}, abstract = {The upcoming change of legislation in some European countries where wastewater treatment facilities will start to be taxed based on direct greenhouse gas (GHG) emissions will force water utilities to take a closer look at nitrous oxide (N2O) production. In this study, we report for the first time N2O emissions from two full-scale size membrane aerated biofilm reactors (MABR) (R1, R2) from two different manufacturers treating municipal wastewater. N2O was monitored continuously for 12 months in both the MABR exhaust gas and liquid phase. Multivariate analysis was used to assess process performance. Results show that emission factors (EFN2O) for both R1 and R2 (0.88 ± 1.28 and 0.82 ± 0.86 %) were very similar to each other and below the standard value from the Intergovernmental Panel on Climate Change (IPCC) 2019 (1.6 %). More specifically, N2O was predominantly emitted in the MABR exhaust gas (NTRexh) and was strongly correlated to the ammonia/um load (NHx,load). Nevertheless, the implemented Oxidation Reduction Potential (ORP) control strategy increased the bulk contribution (NTRbulk), impacting the overall EFN2O. A thorough analysis of dynamic data reveals that the changes in the external aeration (EA)/loading rate patterns suggested by ORP control substantially impacted N2O mass transfer and biological production processes. It also suggests that NTRexh is mainly caused by ammonia-oxidizing organisms (AOO) activity, while ordinary heterotrophic organisms (OHO) are responsible for NTRbulk. Different methods for calculating EFN2O were compared, and results showed EFN2O would range from 0.6 to 5.5 depending on the assumptions made. Based on existing literature, a strong correlation between EFN2O and nitrogen loading rate (R[2] = 0.73) was found for different technologies. Overall, an average EFN2O of 0.86 % N2O-N per N load was found with a nitrogen loading rate >200 g N m[-3] d[-1], which supports the hypothesis that MABR technology can achieve intensified biological nutrient removal without increasing N2O emissions.}, } @article {pmid37889017, year = {2023}, author = {Arone, C and Martial, S and Burlaud-Gaillard, J and Thoulouze, M-I and Roingeard, P and Dutartre, H and Muriaux, D}, title = {HTLV-1 biofilm polarization maintained by tetraspanin CD82 is required for efficient viral transmission.}, journal = {mBio}, volume = {}, number = {}, pages = {e0132623}, doi = {10.1128/mbio.01326-23}, pmid = {37889017}, issn = {2150-7511}, abstract = {The human T-lymphotropic virus type 1 (HTLV-1) is an oncogenic retrovirus whose transmission relies primarily on cell-to-cell contacts as cell-free viruses are poorly infectious. Among the intercellular transmission routes described, HTLV-1 biofilms are adhesive structures polarized at the cell surface that confine virions in a protective environment, which is believed to promote their simultaneous delivery during infection. Here, we show that several tetraspanins are enriched in HTLV-1 biofilms and incorporated into the viral envelope. However, we report that only the tetraspanin CD82 interacts with HTLV-1 Gag proteins which initiates their polarization into viral biofilms. Also, we demonstrate that CD82 maintains HTLV-1 biofilm polarization and favors viral transmission, as its silencing induces a complete reorganization of viral clusters at the cell surface and reduces the ability of infected T-cells to transmit the virus. Our results highlight the crucial role of CD82 and its glycosylation state in the architectural organization of HTLV-1 biofilms and their subsequent transfer through intercellular contacts.IMPORTANCEIn the early stages of infection, human T-lymphotropic virus type 1 (HTLV-1) dissemination within its host is believed to rely mostly on cell-to-cell contacts. Past studies unveiled a novel mechanism of HTLV-1 intercellular transmission based on the remodeling of the host-cell extracellular matrix and the generation of cell-surface viral assemblies whose structure, composition, and function resemble bacterial biofilms. These polarized aggregates of infectious virions, identified as viral biofilms, allow the bulk delivery of viruses to target cells and may help to protect virions from immune attacks. However, viral biofilms' molecular and functional description is still in its infancy, although it is crucial to fully decipher retrovirus pathogenesis. Here, we explore the function of cellular tetraspanins (CD9, CD81, CD82) that we detect inside HTLV-1 particles within biofilms. Our results demonstrate specific roles for CD82 in the cell-surface distribution and intercellular transmission of HTLV-1 biofilms, which we document as two essential parameters for efficient viral transmission. At last, our findings indicate that N-glycosylation of cell-surface molecules, including CD82, is required for the polarization of HTLV-1 biofilms and for the efficient transmission of HTLV-1 between T-lymphocytes.}, } @article {pmid37888282, year = {2023}, author = {Oyardi, O and Demir, ES and Alkan, B and Komec, S and Genc, GE and Aygun, G and Teke, L and Turan, D and Erturan, Z and Savage, PB and Guzel, CB}, title = {Phenotypic Investigation of Virulence Factors, Susceptibility to Ceragenins, and the Impact of Biofilm Formation on Drug Efficacy in Candida auris Isolates from Türkiye.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, doi = {10.3390/jof9101026}, pmid = {37888282}, issn = {2309-608X}, abstract = {Candida auris has emerged as a significant fungal threat due to its rapid worldwide spread since its first appearance, along with its potential for antimicrobial resistance and virulence properties. This study was designed to examine virulence characteristics, the efficacy of ceragenins, and biofilm-derived drug resistance in seven C. auris strains isolated from Turkish intensive care patients. It was observed that none of the tested strains exhibited proteinase or hemolysis activity; however, they demonstrated weak phospholipase and esterase activity. In addition, all strains were identified as having moderate to strong biofilm formation characteristics. Upon determining the minimum inhibitory concentrations (MIC) of ceragenins, it was discovered that CSA-138 exhibited the highest effectiveness with a MIC range of 1-0.5 µg/mL, followed by CSA-131 with a MIC of 1 µg/mL. Also, antimicrobial agents destroyed mature biofilms at high concentrations (40-1280 µg/mL). The investigation revealed that the strains isolated from Türkiye displayed weak exoenzyme activities. Notably, the ceragenins exhibited effectiveness against these strains, suggesting their potential as a viable treatment option.}, } @article {pmid37888211, year = {2023}, author = {Malinovská, Z and Čonková, E and Váczi, P}, title = {Biofilm Formation in Medically Important Candida Species.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, doi = {10.3390/jof9100955}, pmid = {37888211}, issn = {2309-608X}, abstract = {Worldwide, the number of infections caused by biofilm-forming fungal pathogens is very high. In human medicine, there is an increasing proportion of immunocompromised patients with prolonged hospitalization, and patients with long-term inserted drains, cannulas, catheters, tubes, or other artificial devices, that exhibit a predisposition for colonization by biofilm-forming yeasts. A high percentage of mortality is due to candidemia caused by medically important Candida species. Species of major clinical significance include C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, and C. auris. The association of these pathogenic species in the biofilm structure is a serious therapeutic problem. Candida cells growing in the form of a biofilm are able to resist persistent therapy thanks to a combination of their protective mechanisms and their ability to disseminate to other parts of the body, thus representing a threat from the perspective of a permanent source of infection. The elucidation of the key mechanisms of biofilm formation is essential to progress in the understanding and treatment of invasive Candida infections.}, } @article {pmid37888151, year = {2023}, author = {Bihn, SK and Son, K and Son, YT and Dahal, RH and Kim, S and Kim, J and Hwang, JH and Kwon, SM and Lee, JH and Kim, HD and Lee, JM and Jin, MU and Lee, KB}, title = {In Vitro Biofilm Formation on Zirconia Implant Surfaces Treated with Femtosecond and Nanosecond Lasers.}, journal = {Journal of functional biomaterials}, volume = {14}, number = {10}, pages = {}, doi = {10.3390/jfb14100486}, pmid = {37888151}, issn = {2079-4983}, support = {2022R1C1C2007040//National Research Foundation of Korea (NRF) grant funded by the Korean government/ ; 20018114//Bio Industry Technology Development Program of the Korea Evaluation Institute of Industrial Technology (KEIT)/ ; P0017662//Korea Institute for Advancement of Technology (KIAT) grant funded by the Ministry of Trade, Industry and Energy (MOTIE)/ ; 2022RIS-006//National Research Foundation of Korea (NRF) grant funded by the Ministry of Education (MOE)/ ; }, abstract = {(1) Background: The purpose of this study was to evaluate how a zirconia implant surface treated with laser technology affects the degree of biofilm formation. (2) Methods: Experimental titanium (Ti) disks were produced that were sandblasted with large grit and acid-etched (T), and they were compared with zirconia (ZrO2) discs with a machined (M) surface topography; a hydrophilic surface topography with a femtosecond laser (HF); and a hydrophobic surface topography with a nanosecond laser (HN) (N = 12 per surface group). An in vitro three-species biofilm sample (Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi)) was applied to each disc type, and bacterial adhesion was assessed after 48 and 72 h of incubation using an anaerobic flow chamber model. Statistical significance was determined using the Kruskal-Wallis H test, with Bonferroni correction used for the post-hoc test (α = 0.05). (3) Results: Compared to the T group, the M group exhibited more than twice as many viable bacterial counts in the three-species biofilm samples (p < 0.05). In comparison to the T group, the HF group had significantly higher viable bacterial counts in certain biofilm samples at 48 h (Aa and Pi) and 72 h (Pi) (p < 0.05). The HN group had higher viable bacterial counts in Pi at 48 h (5400 CFU/mL, p < 0.05) than the T group (4500 CFU/mL), while showing significantly lower viable bacterial counts in Pg at both 48 (3010 CFU/mL) and 72 h (3190 CFU/mL) (p < 0.05). (4) Conclusions: The surface treatment method for zirconia discs greatly influences biofilm formation. Notably, hydrophobic surface treatment using a nanosecond laser was particularly effective at inhibiting Pg growth.}, } @article {pmid37888008, year = {2023}, author = {Kim, Y and Anburajan, P and Kim, H and Oh, HS}, title = {Inhibiting Biofilm Formation via Simultaneous Application of Nitric Oxide and Quorum Quenching Bacteria.}, journal = {Membranes}, volume = {13}, number = {10}, pages = {}, doi = {10.3390/membranes13100836}, pmid = {37888008}, issn = {2077-0375}, support = {None//Seoul National University of Science and Technology/ ; }, abstract = {Membrane biofouling is an inevitable challenge in membrane-based water treatment systems such as membrane bioreactors. Recent studies have shown that biological approaches based on bacterial signaling can effectively control biofilm formation. Quorum quenching (QQ) is known to inhibit biofilm growth by disrupting quorum sensing (QS) signaling, while nitric oxide (NO) signaling helps to disperse biofilms. In this study, batch biofilm experiments were conducted to investigate the impact of simultaneously applying NO signaling and QQ for biofilm control using Pseudomonas aeruginosa PAO1 as a model microorganism. The NO treatment involved the injection of NONOates (NO donor compounds) into mature biofilms, while QQ was implemented by immobilizing QQ bacteria (Escherichia coli TOP10-AiiO or Rhodococcus sp. BH4) in alginate or polyvinyl alcohol/alginate beads to preserve the QQ activity. When QQ beads were applied together with (Z)-1-[N-(3-aminopropyl)-N-(n-propyl) amino]diazen-1-ium-1,2-diolate (PAPA NONOate), they achieved a 39.0% to 71.3% reduction in biofilm formation, which was substantially higher compared to their individual applications (16.0% to 54.4%). These findings highlight the significant potential of combining QQ and NO technologies for effective biofilm control across a variety of processes that require enhanced biofilm inhibition.}, } @article {pmid37887760, year = {2023}, author = {Wultańska, D and Karpiński, P and Piotrowski, M and Pituch, H}, title = {The Effect of Subinhibitory Concentration of Metronidazole on the Growth and Biofilm Formation on Toxigenic Clostridioides difficile Strains Belonging to Different Ribotypes.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {10}, pages = {}, doi = {10.3390/pathogens12101244}, pmid = {37887760}, issn = {2076-0817}, support = {2017/25/N/NZ6/01763//National Science Center/ ; }, abstract = {Clostridioides difficile is a predominant nosocomial pathogen within the healthcare setting able to produce biofilms. Sub-minimum inhibitory concentrations (sub-MICs) of antibiotics trigger mechanisms affecting bacterial virulence, including increased adhesion and biofilm formation. The aim of this study was to investigate how sub-MICs of metronidazole affect the biofilm formation of C. difficile strains. We tested 14 reference and clinical C. difficile strains, including hypervirulent strains of RT027. The MICs of metronidazole for the tested strains were determined using the broth microdilution method. Biofilm formation was evaluated using confocal laser scanning microscopy. The C. difficile strains belonging to RT027 produced the highest amounts of biofilm. The results of confocal laser scanning microscopy showed that all the tested C. difficile strains developed larger biofilms with diversified architectures upon exposure to sub-MICs of metronidazole. In our study, we reveal that sub-MIC concentrations of metronidazole affect the biofilm formation of clinical and reference strains of C. difficile. Importantly, metronidazole induces biofilm formation via hypervirulent RT027 strains.}, } @article {pmid37887257, year = {2023}, author = {Artini, M and Papa, R and Vrenna, G and Trecca, M and Paris, I and D'Angelo, C and Tutino, ML and Parrilli, E and Selan, L}, title = {Antarctic Marine Bacteria as a Source of Anti-Biofilm Molecules to Combat ESKAPE Pathogens.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {10}, pages = {}, doi = {10.3390/antibiotics12101556}, pmid = {37887257}, issn = {2079-6382}, support = {RM1221813859CA94//Bando Ateneo Sapienza 2022/ ; }, abstract = {The ESKAPE pathogens, including bacteria such as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, pose a global health threat due to their ability to resist antimicrobial drugs and evade the immune system. These pathogens are responsible for hospital-acquired infections, especially in intensive care units, and contribute to the growing problem of multi-drug resistance. In this study, researchers focused on exploring the potential of Antarctic marine bacteria as a source of anti-biofilm molecules to combat ESKAPE pathogens. Four Antarctic bacterial strains were selected, and their cell-free supernatants were tested against 60 clinical ESKAPE isolates. The results showed that the supernatants did not exhibit antimicrobial activity but effectively prevented biofilm formation and dispersed mature biofilms. This research highlights the promising potential of Antarctic bacteria in producing compounds that can counteract biofilms formed by clinically significant bacterial species. These findings contribute to the development of new strategies for preventing and controlling infections caused by ESKAPE pathogens.}, } @article {pmid37887240, year = {2023}, author = {Tapia-Rodriguez, MR and Cantu-Soto, EU and Vazquez-Armenta, FJ and Bernal-Mercado, AT and Ayala-Zavala, JF}, title = {Inhibition of Acinetobacter baumannii Biofilm Formation by Terpenes from Oregano (Lippia graveolens) Essential Oil.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {10}, pages = {}, doi = {10.3390/antibiotics12101539}, pmid = {37887240}, issn = {2079-6382}, abstract = {Acinetobacter baumannii is a nosocomial pathogen known for its ability to form biofilms, leading to persistent infections and antibiotic resistance. The limited effective antibiotics have encouraged the development of innovative strategies such as using essential oils and their constituents. This study evaluated the efficacy of oregano (Lippia graveolens) essential oil (OEO) and its terpene compounds, carvacrol and thymol, in inhibiting A. baumannii biofilms. These treatments showed a minimum inhibitory concentration of 0.6, 0.3, and 2.5 mg/mL and a minimum bactericidal concentration of 1.2, 0.6, and 5 mg/mL, respectively. Sub-inhibitory doses of each treatment and the OEO significantly reduced biofilm biomass and the covered area of A. baumannii biofilms as measured by fluorescence microscopy. Carvacrol at 0.15 mg/mL exhibited the most potent efficacy, achieving a remarkable 95% reduction. Sub-inhibitory concentrations of carvacrol significantly reduced the biofilm formation of A. baumannii in stainless steel surfaces by up to 1.15 log CFU/cm[2] compared to untreated bacteria. The OEO and thymol exhibited reductions of 0.6 log CFU/cm[2] and 0.4 log CFU/cm[2], respectively, without affecting cell viability. Moreover, the terpenes inhibited twitching motility, a crucial step in biofilm establishment, with carvacrol exhibiting the highest inhibition, followed by OEO and thymol. The study provides valuable insights into the potential of terpenes as effective agents against A. baumannii biofilms, offering promising avenues for developing novel strategies to prevent persistent infections and overcome antibiotic resistance.}, } @article {pmid37887191, year = {2023}, author = {Burke, ZDC and Hart, CM and Kelley, BV and Mamouei, Z and Blumstein, GW and Hamad, C and Hori, K and Cevallos, N and Villalpando, C and Truong, N and Turkmani, A and Ralston, M and Kavanaugh, A and Tenorio, E and Kauvar, LM and Li, A and Prunet, N and Stavrakis, AI and Bernthal, NM}, title = {Monoclonal Antibody Disrupts Biofilm Structure and Restores Antibiotic Susceptibility in an Orthopedic Implant Infection Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {10}, pages = {}, doi = {10.3390/antibiotics12101490}, pmid = {37887191}, issn = {2079-6382}, support = {5K08AR069112-01 and T32AR059033/AR/NIAMS NIH HHS/United States ; }, abstract = {Bacterial biofilms on orthopedic implants are resistant to the host immune response and to traditional systemic antibiotics. Novel therapies are needed to improve patient outcomes. TRL1068 is a human monoclonal antibody (mAb) against a biofilm anchoring protein. For assessment of this agent in an orthopedic implant infection model, efficacy was measured by reduction in bacterial burden of Staphylococcus aureus, the most common pathogen for prosthetic joint infections (PJI). Systemic treatment with the biofilm disrupting mAb TRL1068 in conjunction with vancomycin eradicated S. aureus from steel pins implanted in the spine for 26 of 27 mice, significantly more than for vancomycin alone. The mechanism of action was elucidated by two microscopy studies. First, TRL1068 was localized to biofilm using a fluorescent antibody tag. Second, a qualitative effect on biofilm structure was observed using scanning electron microscopy (SEM) to examine steel pins that had been treated in vivo. SEM images of implants retrieved from control mice showed abundant three-dimensional biofilms, whereas those from mice treated with TRL1068 did not. Clinical Significance: TRL1068 binds at high affinity to S. aureus biofilms, thereby disrupting the three-dimensional structure and significantly reducing implant CFUs in a well-characterized orthopedic model for which prior tested agents have shown only partial efficacy. TRL1068 represents a promising systemic treatment for orthopedic implant infection.}, } @article {pmid37886402, year = {2023}, author = {Rikvold, PT and Kambourakis Johnsen, K and Leonhardt, D and Møllebjerg, A and Nielsen, SM and Skov Hansen, LB and Meyer, RL and Schlafer, S}, title = {A New Device for In Situ Dental Biofilm Collection Additively Manufactured by Direct Metal Laser Sintering and Vat Photopolymerization.}, journal = {3D printing and additive manufacturing}, volume = {10}, number = {5}, pages = {1036-1045}, pmid = {37886402}, issn = {2329-7670}, abstract = {Dental biofilms are complex medical biofilms that cause caries, the most prevalent disease of humankind. They are typically collected using handcrafted intraoral devices with mounted carriers for biofilm growth. As the geometry of handcrafted devices is not standardized, the shear forces acting on the biofilms and the access to salivary nutrients differ between carriers. The resulting variability in biofilm growth renders the comparison of different treatment modalities difficult. The aim of the present work was to design and validate an additively manufactured intraoral device with a dental bar produced by direct metal laser sintering and vat photopolymerized inserts with standardized geometry for the mounting of biofilm carriers. Additive manufacturing reduced the production time and cost, guaranteed an accurate fit of the devices and facilitated the handling of carriers without disturbing the biofilm. Biofilm growth was robust, with increasing thickness over time and moderate inter- and intraindividual variation (coefficients of variance 0.48-0.87). The biofilms showed the typical architecture and composition of dental biofilms, as evidenced by confocal microscopy and 16S rRNA gene sequencing. Deeper inserts offering increased protection from shear tended to increase the biofilm thickness, whereas prolonged exposure to sucrose during growth increased the biofilm volume but not the thickness. Ratiometric pH imaging revealed considerable pH variation between participants and also inside single biofilms. Intraoral devices for biofilm collection constitute a new application for medical additive manufacturing and offer the best possible basis for studying the influence of different treatment modalities on biofilm growth, composition, and virulence. The Clinical Trial Registration number is: 1-10-72-193-20.}, } @article {pmid37885304, year = {2023}, author = {Sonesson, A and Baumgarten, M and Bhongir, R and Engelsberg, K}, title = {Is a bacterial biofilm in the lacrimal sac the cause of chronic refractory dacryocystitis? - A pilot study.}, journal = {Orbit (Amsterdam, Netherlands)}, volume = {}, number = {}, pages = {1-5}, doi = {10.1080/01676830.2023.2269580}, pmid = {37885304}, issn = {1744-5108}, abstract = {PURPOSE: A pilot study to identify bacterial biofilm in the lacrimal sacs of patients with chronic dacryocystitis, and in patients with epiphora but without discharge, using scanning electron microscopy.

METHODS: Five patients: two with nasolacrimal duct obstruction without dacryocystitis, and three with dacryocystitis refractory to antibiotics, underwent external dacryocystorhinostomy. One control patient without infection was included. Bacterial cultures were obtained from the lumen of the lacrimal sac to analyze possible bacterial growth, including antibiotic resistance. Biopsies were taken from all lacrimal sacs and prepared for light and scanning electron microscopy.

RESULTS: Scanning electron microscopy of all the lacrimal sac samples revealed structures consistent with bacterial communities and adjacent extracellular material, indicating biofilm formation. This was most prominent in one of the patients with chronic dacryocystitis. Bacteria were found not only on the luminal surface of the sac, but also within the tissue of the sac. Bacterial growth was identified in samples from two patients with chronic dacryocystitis, whereas samples from the other three patients showed no bacterial growth.

CONCLUSION: Lack of patency of the lacrimal duct predisposes to bacterial growth, even in patients with no clinically confirmed infection of the lacrimal sac. The finding of a biofilm in patients with chronic dacryocystitis explains the lack of efficiency of antibiotic treatment at the concentrations used in clinical practice.}, } @article {pmid37884887, year = {2023}, author = {Yue, Y and Chen, K and Sun, C and Ahmed, S and Ojha, SC}, title = {Antimicrobial peptidase lysostaphin at subinhibitory concentrations modulates staphylococcal adherence, biofilm formation, and toxin production.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {311}, pmid = {37884887}, issn = {1471-2180}, abstract = {BACKGROUND: The ability of antimicrobial agents to affect microbial adherence to eukaryotic cell surfaces is a promising antivirulence strategy for combating the global threat of antimicrobial resistance. Inadequate use of antimicrobials has led to widespread instances of suboptimal antibiotic concentrations around infection sites. Therefore, we aimed to examine the varying effect of an antimicrobial peptidase lysostaphin (APLss) on staphylococcal adherence to host cells, biofilm biomass formation, and toxin production as a probable method for mitigating staphylococcal virulence.

RESULTS: Initially, soluble expression in E. coli and subsequent purification by immobilized-Ni[2+] affinity chromatography (IMAC) enabled us to successfully produce a large quantity of highly pure ~ 28-kDa His-tagged mature APLss. The purified protein exhibited potent inhibitory effects against both methicillin-sensitive and methicillin-resistant staphylococcal strains, with minimal inhibitory concentrations (MICs) ranging from 1 to 2 µg/mL, and ultrastructural analysis revealed that APLss-induced concentration-specific changes in the morphological architecture of staphylococcal surface membranes. Furthermore, spectrophotometric and fluorescence microscopy revealed that incubating staphylococcal strains with sub-MIC and MIC of APLss significantly inhibited staphylococcal adherence to human vaginal epithelial cells and biofilm biomass formation. Ultimately, transcriptional investigations revealed that APLss inhibited the expression of agrA (quorum sensing effector) and other virulence genes related to toxin synthesis.

CONCLUSIONS: Overall, APLss dose-dependently inhibited adhesion to host cell surfaces and staphylococcal-associated virulence factors, warranting further investigation as a potential anti-staphylococcal agent with an antiadhesive mechanism of action using in vivo models of staphylococcal toxic shock syndrome.}, } @article {pmid37884321, year = {2023}, author = {Laperche, J and Barrett, CC and Boduch, A and Glasser, J and Clippert, D and Garcia, DR and Antoci, V}, title = {Mechanically Stable Rifampin Antibiotic Cement Inhibits Pseudomonas aeruginosa Biofilm Surface Growth.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {}, number = {}, pages = {}, doi = {10.1002/jor.25720}, pmid = {37884321}, issn = {1554-527X}, abstract = {Rifampin has been proven to be effective in the treatment of prosthetic infections due to its ability to intercalate into biofilms. The use of rifampin in antibiotic spacers is not well described, which would be especially important in the local periprosthetic environment where parenteral doses have poor penetration. Null hypothesis tests if rifampin use in PMMA cement will show no clinically significant impact on mechanical strength at antibiotic concentrations that remain bactericidal. Test antibiotic cement samples supplemented with 0mg, 30mg, 50mg, 100mg, 150mg or 200mg of rifampin into a standard 40g bag were tested for compression to failure using published ASTM standards. The samples were then inoculated with Pseudomonas aeruginosa and either evaluated for lipo-polysacharide (LPS) presence as a marker of biofilm or tested by elution as the Kirby Bauer assay. Rifampin concentrations of 30mg, and 50mg, showed no statistically different mechanical characteristics to control PMMA (p>0.05). The 100mg sample fell within the acceptable range of compressive strength and had significantly less LPS and bacterial presence compared to control at 12 and 24 hours. The ability of PMMA with 100mg of rifampin to maintain its structural integrity and have significant bacterial inhibition at 12 and 24 hours makes it a great candidate as an antibiotic bone cement additive. PMMA loaded with up to 100mg of rifampin shows promise in the treatment and prevention of PJI for total knee and total hip arthroplasty. This article is protected by copyright. All rights reserved.}, } @article {pmid37884397, year = {2023}, author = {Gheorghita, AA and Wozniak, DJ and Parsek, MR and Howell, PL}, title = {Pseudomonas aeruginosa biofilm exopolysaccharides: Assembly, function, and degradation.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuad060}, pmid = {37884397}, issn = {1574-6976}, abstract = {The biofilm matrix is a fortress; sheltering bacteria in a protective and nourishing barrier that allows for growth and adaptation to various surroundings. A variety of different components are found within the matrix including water, lipids, proteins, extracellular DNA, RNA, membrane vesicles, phages, and exopolysaccharides. As part of its biofilm matrix, Pseudomonas aeruginosa is genetically capable of producing three chemically distinct exopolysaccharides - alginate, Pel, and Psl - each of which has a distinct role in biofilm formation and immune evasion during infection. The polymers are produced by highly conserved mechanisms of secretion, involving many proteins that span both the inner and outer bacterial membranes. Experimentally determined structures, predictive modelling of proteins whose structures are yet to be solved, and structural homology comparisons give us insight into the molecular mechanisms of these secretion systems, from polymer synthesis to modification and export. Here, we review recent advances that enhance our understanding of P. aeruginosa multi-protein exopolysaccharide biosynthetic complexes, and how the glycoside hydrolases/lyases within these systems have been commandeered for antimicrobial applications.}, } @article {pmid37882623, year = {2023}, author = {Petit, M and Tessier, J and Sahli, C and Schmitzer, AR}, title = {Confronting the Threat: Designing Highly Effective bis-Benzimidazolium Agents to Overcome Biofilm Persistence and Antimicrobial Resistance.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00289}, pmid = {37882623}, issn = {2373-8227}, abstract = {The objective of this study is to take the initial steps toward developing novel antibiotics to counteract the escalating problem of antimicrobial and bacterial persistence, particularly in relation to biofilms. Our approach involves emulating the structural characteristics of cationic antimicrobial peptides. To circumvent resistance development, we have designed a library of bis-benzimidazolium salts that selectively target the microbial membranes in a nonspecific manner. To explore their structure-activity relationship, we conducted experiments using these compounds on various pathogens known for their resistance to conventional antibiotics, including Gram-positive methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), and Gram-negative Escherichia coli (E. coli). Notably, two bis-benzimidazolium salts exhibited robust antimicrobial activity while maintaining a high level of selectivity compared with mammalian cells. Our investigations revealed significant antibiofilm activity, as these compounds rapidly acted against established biofilms. In addition, bis-benzimidazolium compounds exhibited consistent results in resistance development and cross-resistance studies. Consequently, amphiphilic bis-benzimidazolium salts hold promise as potential candidates to combat resistance-associated infections.}, } @article {pmid37882569, year = {2023}, author = {Fernández-Juárez, V and Hallstrøm, S and Pacherres, CO and Wang, J and Coll-Garcia, G and Kühl, M and Riemann, L}, title = {Biofilm formation and cell plasticity drive diazotrophy in an anoxygenic phototrophic bacterium.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0102723}, doi = {10.1128/aem.01027-23}, pmid = {37882569}, issn = {1098-5336}, abstract = {Non-cyanobacterial diazotrophs (NCDs) are widespread and active in marine waters. The carbon and low-oxygen (O2) conditions required for their N2 fixation may be encountered on marine particles, while a putative role of light remains uninvestigated. This study explored factors that regulate N2 fixation in Rhodopseudomonas sp. BAL398-a anoxygenic phototrophic bacterium isolated from low-salinity surface waters. Light (250 µmol photons m[-2] s[-1]) and anoxia (0 µM O2) stimulated growth and N2 fixation; however, diazotrophy in light was dependent on high organic carbon levels (35 mM, glucose:succinate). Immunolabeling revealed that cellular nitrogenase levels increased with light, decreasing inorganic nitrogen (N) and ambient O2 (250 µM). Light and O2 stimulated motility and biofilm formation on surfaces, and N2 fixation rates increased compared to the control treatment. N2 fixation rates were positively correlated with the formation of rosette-like cellular structures, and an increased concentration of nitrogenase was observed toward the center of these structures, which increased their occurrence 600 times when cultures reached maximum N2 fixation rates vs when they had low rates. Interestingly, N2 fixation was not completely inhibited under oxic conditions and was accompanied by increased formation of capsules and cysts. Rosettes, as well as capsules and cysts, may thus serve as protection against O2. Our study reveals the physiological adaptations that underlie N2 fixation in an anoxygenic phototroph, emphasizing the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions, and underscores the need for deciphering the importance of light for marine NCDs.IMPORTANCEThe contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters.}, } @article {pmid37881370, year = {2023}, author = {Sultan, M and Arya, R and Chaurasia, AK and Kim, KK}, title = {Sensor histidine kinases kdpD and aauS regulate biofilm and virulence in Pseudomonas aeruginosa PA14.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1270667}, pmid = {37881370}, issn = {2235-2988}, abstract = {Pseudomonas aeruginosa is a multidrug-resistant opportunistic human pathogen that utilizes two-component systems (TCSs) to sense pathophysiological signals and coordinate virulence. P. aeruginosa contains 64 sensor histidine kinases (HKs) and 72 response regulators (RRs) that play important roles in metabolism, bacterial physiology, and virulence. However, the role of some TCSs in virulence remains uncharacterized. In this study, we evaluated the virulence potential of some uncharacterized sensor HK and RR knockouts in P. aeruginosa using a Galleria mellonella infection model. Furthermore, we demonstrated that KdpD and AauS HKs regulate virulence by affecting P. aeruginosa biofilm formation and motility. Both ΔkdpD and ΔaauS showed reduced biofilm and motility which were confirmed by restored phenotypes upon complementation. Moreover, ΔkdpD and ΔaauS exhibited increased survival of HeLa cells and G. mellonella during in vivo infection. Altered expression of the transcriptional regulators anR and lasR, along with the virulence genes lasA, pelA, cupA, pqsA, pqsB, pqsC, and pqsD in the mutant strains elucidated the mechanism by which ΔkdpD and ΔaauS affect virulence. These findings confirm that kdpD and aauS play important roles in P. aeruginosa pathogenesis by regulating biofilm formation and motility.}, } @article {pmid37881066, year = {2023}, author = {Haddadi, MH and Khoshnood, S and Koupaei, M and Heidary, M and Moradi, M and Jamshidi, A and Behrouj, H and Movahedpour, A and Maleki, MH and Ghanavati, R}, title = {Evaluating the incidence of ampC-lactamase genes, biofilm formation, and antibiotic resistance among hypervirulent and classical Klebsiella pneumoniae strains.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad241}, pmid = {37881066}, issn = {1365-2672}, abstract = {AIM: Both immunocompetent and healthy individuals can become life-threateningly ill when exposed to the hypervirulent (hvKp) strains of Klebsiella pneumoniae (Kp). The main objectives of this study were to evaluate the presence of ampC-lactamase genes, biofilm formation, and antibiotic resistance in clinical strains of hvKp and cKp (classical K. pneumoniae).

MATERIALS AND METHODS: Kp strains were collected from patients referred to Shahidzadeh Hospital in Behbahan city, Khuzestan Province, Iran. Several techniques were used to identify hvKp. The hypermucoviscosity phenotype was determined using the string test. Isolates that developed dark colonies on tellurite agar were assumed to be hvKp strains. If any of the iucA, iutA, or peg-344 genes were detected, the isolates were classified as hvKp. Phenotypic and genotypic detection of AmpC β-lactamases of hvKp strains was performed by combined disk method and PCR, respectively. In addition, crystal violet staining was used to determine the biofilm formation of these isolates.

RESULTS: For this study, 76 non-duplicative isolates of Kp were collected. Overall, 22 (28.94%) strains had positive string test results, and 31 (40.78%) isolates were grown in tellurite-containing medium. The genes iucA and iutA or peg-344 were found in 23.68% of all Kp strains and in 50% of tellurite-resistant isolates, respectively. The most effective antibiotics against hvKp isolates were tetracycline (85.52%) and chloramphenicol (63.15%). Using the cefoxitin disc diffusion method, we observed that 56.57% (43/76) of the strains were AmpC producer. A total of 30.26% (n = 23/76) of the isolates tested positive for at least one ampC gene, including blaDHA (52.63%, n = 40), blaCIT (40.78%, n = 31), blaACC (19.76%, n = 15), blaMOX (25%, n = 19), and blaFOX (43.42%, n = 33). Biofilm formation analysis revealed that most hvKp isolates were weak (n = 6, 40%) and moderate (n = 5, 33.33%) biofilm producers.

CONCLUSION: Healthcare practitioners should consider the possibility of the existence and acquisition of hvKp everywhere. The exact mechanisms of bacterial acquisition are also unknown, and it is unclear whether the occurrence of infections is related to healthcare or not. Thus, there are still many questions about hvKp that need to be investigated.}, } @article {pmid37880467, year = {2023}, author = {Ali, ASBE and Ozler, B and Baddal, B}, title = {Characterization of Virulence Genes Associated with Type III Secretion System and Biofilm Formation in Pseudomonas aeruginosa Clinical Isolates.}, journal = {Current microbiology}, volume = {80}, number = {12}, pages = {389}, pmid = {37880467}, issn = {1432-0991}, abstract = {Pseudomonas aeruginosa is a common pathogen with an increasing multidrug resistance (MDR) phenotype. Its virulence determinants include many factors such as antimicrobial resistance, biofilm formation, and type III secretion system (T3SS) which correlate with disease severity. There are no reports regarding the virulence features of P. aeruginosa in Cyprus. The aim of this study was to investigate the frequency and distribution of selected virulence-encoding genes and evaluate the biofilm formation potential as well as antibiotic resistance rates of isolates in the region. One hundred clinical P. aeruginosa isolates were obtained from clinical specimens and were identified using standard microbiological techniques. Antimicrobial susceptibility was assessed using the VITEK-2 system and biofilm quantification was performed by the microtiter plate assay with crystal violet staining. The presence of algD, exoU, exoT, and exoS was evaluated using polymerase chain reaction (PCR). Among all isolates, 35% were strong biofilm former, 28% were moderate biofilm former, 19% were weak biofilm former, and 18% were non-biofilm former. The rates of MDR and extensive drug resistance (XDR) were 26% and 1%. PCR analysis indicated that 93% of the isolates were algD positive. T3SS genes exoT, exoS, and exoU were detected in 91%, 63%, and 32% of the isolates, respectively. There was a high frequency of exoT + /exoS + genotype (61%), whereas exoT + /exoU + (32%) and exoS + /exoU + (2%) genotypes were relatively uncommon. This study reports the first dataset on the molecular profile of P. aeruginosa in Cyprus. Our results demonstrated that most strains have the biofilm-forming capacity with an algD-positive genotype and the majority carry exoT and exoS with a high frequency of exoT + /exoS + genotype.}, } @article {pmid37878651, year = {2023}, author = {Jaramillo-Rodríguez, JB and Vega-Alvarado, L and Rodríguez-Torres, LM and Huerta-Miranda, GA and Hernández-Eligio, A and Juarez, K}, title = {Global transcriptional analysis of Geobacter sulfurreducens gsu1771 mutant biofilm grown on two different support structures.}, journal = {PloS one}, volume = {18}, number = {10}, pages = {e0293359}, doi = {10.1371/journal.pone.0293359}, pmid = {37878651}, issn = {1932-6203}, abstract = {Electroactive biofilms formation by the metal-reducing bacterium Geobacter sulfurreducens is a step crucial for bioelectricity generation and bioremediation. The transcriptional regulator GSU1771 controls the expression of essential genes involved in electron transfer and biofilm formation in G. sulfurreducens, with GSU1771-deficient producing thicker and more electroactive biofilms. Here, RNA-seq analyses were conducted to compare the global gene expression patterns of wild-type and Δgsu1771 mutant biofilms grown on non-conductive (glass) and conductive (graphite electrode) materials. The Δgsu1771 biofilm grown on the glass surface exhibited 467 differentially expressed (DE) genes (167 upregulated and 300 downregulated) versus the wild-type biofilm. In contrast, the Δgsu1771 biofilm grown on the graphite electrode exhibited 119 DE genes (79 upregulated and 40 downregulated) versus the wild-type biofilm. Among these DE genes, 67 were also differentially expressed in the Δgsu1771 biofilm grown on glass (56 with the same regulation and 11 exhibiting counter-regulation). Among the upregulated genes in the Δgsu1771 biofilms, we identified potential target genes involved in exopolysaccharide synthesis (gsu1961-63, gsu1959, gsu1972-73, gsu1976-77). RT-qPCR analyses were then conducted to confirm the differential expression of a selection of genes of interest. DNA-protein binding assays demonstrated the direct binding of the GSU1771 regulator to the promoter region of pgcA, pulF, relA, and gsu3356. Furthermore, heme-staining and western blotting revealed an increase in c-type cytochromes including OmcS and OmcZ in Δgsu1771 biofilms. Collectively, our findings demonstrated that GSU1771 is a global regulator that controls extracellular electron transfer and exopolysaccharide synthesis in G. sulfurreducens, which is crucial for electroconductive biofilm development.}, } @article {pmid37878407, year = {2023}, author = {Goudarzi, M and Haghighi, M and Mirzaei, Y and Pourhossein, B and Dadashi, M and Nasiri, MJ}, title = {Genetic diversity and biofilm formation of invasive and noninvasive Streptococcus agalactiae isolates: Emergence of hypervirulent CC19 strains in Tehran, Iran.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {}, number = {}, pages = {}, doi = {10.1556/030.2023.02085}, pmid = {37878407}, issn = {1588-2640}, abstract = {The prevalence of Streptococcus agalactiae infections in adult populations is increasing. The current study aimed to characterize the genetic features of S. agalactiae strains responsible for different infections. A cross-sectional study was performed on 65 S. agalactiae strains (30 invasive and 35 noninvasive) isolated from non-pregnant women. All S. agalactiae isolates were confirmed by atr and dltS PCR assays. Antibiotic susceptibility patterns were determined using the disk diffusion method. Biofilm production was investigated by microtiter plate assay. PCR was done to detect resistance determinants. Isolates were characterized using the multilocus sequence typing (MLST) method. cMLSB, iMLSB, and M phenotypes accounted for 47.7%, 30.8%, and 6.2%, respectively. MDR was detected in 15.4% of noninvasive and 44.6% of invasive isolates. MtP assay indicated that 80% of isolates were biofilm producers. Biofilm formation was common among noninvasive compared with invasive strains (94.3% versus 66.7%). tet (M) (46.2%) and erm (B) (69.2%) were the most prevalent tetracycline and macrolide-resistance genes. The most prevalent serotype was type III (50.8%), followed by Ia (18.4%), II (15.4%), V (12.3%), and IV (3.1%). The frequency of serotype III among biofilm producer strains (81.8%) was found to be significantly higher than that of non-producer isolates (18.2%) (P < 0.05). S. agalactiae was resolved within four clonal complexes, including CC19 (46.2%; in both invasive and noninvasive), followed by CC23 (30.8%; only noninvasive isolates), CC1 (15.4%; only noninvasive isolates) and CC17 (7.6%; only invasive isolates). The main sequence types (STs) found were ST19 (27.7%), ST17 (7.7%), ST27 (6.2%), and ST28 (4.6%) linked with invasive infections and ST23 (18.4%), ST933 (12.3%), ST644 (9.2%), ST19 (7.7%), ST1 (6.2%) found in noninvasive infections. The high prevalence of CC19 and CC23 clones among S. agalactiae strains reflects the emergence of these lineages as successful clones in Iran.}, } @article {pmid37877656, year = {2023}, author = {Lueyar, TK and Karygianni, L and Attin, T and Thurnheer, T}, title = {Dynamic interactions between Candida albicans and different streptococcal species in a multispecies oral biofilm.}, journal = {MicrobiologyOpen}, volume = {12}, number = {5}, pages = {e1381}, doi = {10.1002/mbo3.1381}, pmid = {37877656}, issn = {2045-8827}, support = {//Institutional funds of the University of Zurich/ ; }, abstract = {The oral cavity is colonized by a plethora of bacteria, fungi, and archaea, including streptococci of the mitis group (MSG) and the yeast Candida albicans. This study aims to investigate the role of streptococcal species in the development of oral biofilm and the cross-kingdom interactions between some of the members of the commensal MSG and the pathogen yeast C. albicans using a multispecies supragingival biofilm model. A total of nine different in vitro biofilms were grown, quantified with culture analyses, and visually examined with confocal laser scanning microscopy (CLSM). A four-species biofilm without any streptococcal species was used as a basic biofilm. In each subsequent inoculum, one species of MSG was added and afterward combined with Streptococcus mutans. The eight-species biofilm contained all eight strains used in this study. Culture analyses showed that the presence of S. mutans in a four-species biofilm with Streptococcus oralis or S. oralis subsp. tigurinus did not differ significantly in C. albicans colony-forming unit (CFU) counts compared to biofilms without S. mutans. However, compared to other mitis species, Streptococcus gordonii combined with S. mutans resulted in the lowest CFUs of C. albicans. Visual observation by CLSM showed that biofilms containing both S. mutans and one species of MSG seemed to induce the formation of filamentous form of C. albicans. However, when several species of MSG were combined with S. mutans, C. albicans was again found in its yeast form.}, } @article {pmid37876206, year = {2023}, author = {Babikow, E and Ghaltakhchyan, N and Livingston, T and Qu, Y and Liu, C and Hoxie, A and Sulkowski, T and Bocklage, C and Marsh, A and Phillips, ST and Mitchell, KB and Ribeiro, AA and Jackson, TH and Roach, J and Wu, D and Divaris, K and Jacox, LA}, title = {Longitudinal Microbiome Changes in Supragingival Biofilm Transcriptomes Induced by Orthodontics.}, journal = {JDR clinical and translational research}, volume = {}, number = {}, pages = {23800844231199393}, doi = {10.1177/23800844231199393}, pmid = {37876206}, issn = {2380-0852}, abstract = {INTRODUCTION: Common oral diseases are known to be associated with dysbiotic shifts in the supragingival microbiome, yet most oral microbiome associations with clinical end points emanate from cross-sectional studies. Orthodontic treatment is an elective procedure that can be exploited to prospectively examine clinically relevant longitudinal changes in the composition and function of the supragingival microbiome.

METHODS: A longitudinal cohort study was conducted among 24 adolescent orthodontic patients who underwent saliva and plaque sampling and clinical examinations at time points: before fixed appliance bonding and at 1, 6, and 12 wk thereafter. Clinical indices included bleeding on probing (BOP), mean gingival index (GI), probing depths (PDs), and plaque index (PI). To study the biologically (i.e., transcriptionally) active microbial communities, RNA was extracted from plaque and saliva for RNA sequencing and microbiome bioinformatics analysis. Longitudinal changes in microbiome beta diversity were examined using PERMANOVA tests, and the relative abundance of microbial taxa was measured using Kruskal-Wallis tests, Wilcoxon rank-sum tests, and negative binomial and zero-inflated mixed models.

RESULTS: Clinical measures of oral health deteriorated over time-the proportion of sites with GI and PI ≥1 increased by over 70% between prebonding and 12 wk postbonding while the proportion of sites with PD ≥4 mm increased 2.5-fold. Streptococcus sanguinis, a health-associated species that antagonizes cariogenic pathogens, showed a lasting decrease in relative abundance during orthodontic treatment. Contrarily, caries- and periodontal disease-associated taxa, including Selenomonas sputigena, Leptotrichia wadei, and Lachnoanaerobaculum saburreum, increased in abundance after bonding. Relative abundances of Stomatobaculum longum and Mogibacterium diversum in prebonding saliva predicted elevated BOP 12 wk postbonding, whereas Neisseria subflava was associated with lower BOP.

CONCLUSIONS: This study offers insights into longitudinal community and species-specific changes in the supragingival microbiome transcriptome during fixed orthodontic treatment, advancing our understanding of microbial dysbioses and identifying targets of future health-promoting clinical investigations.

KNOWLEDGE TRANSFER STATEMENT: Bonding braces was associated with subsequent changes in the oral microbiome characterized by increases in disease-associated species, decreases in health-associated species, and worsened clinical measures of oral health.}, } @article {pmid37875896, year = {2023}, author = {Jiang, Z and Fu, L and Wei, C and Fu, Q and Pan, S}, title = {Antibacterial micro/nanomotors: advancing biofilm research to support medical applications.}, journal = {Journal of nanobiotechnology}, volume = {21}, number = {1}, pages = {388}, pmid = {37875896}, issn = {1477-3155}, abstract = {Multi-drug resistant (MDR) bacterial infections are gradually increasing in the global scope, causing a serious burden to patients and society. The formation of bacterial biofilms, which is one of the key reasons for antibiotic resistance, blocks antibiotic penetration by forming a physical barrier. Nano/micro motors (MNMs) are micro-/nanoscale devices capable of performing complex tasks in the bacterial microenvironment by transforming various energy sources (including chemical fuels or external physical fields) into mechanical motion or actuation. This autonomous movement provides significant advantages in breaking through biological barriers and accelerating drug diffusion. In recent years, MNMs with high penetrating power have been used as carriers of antibiotics to overcome bacterial biofilms, enabling efficient drug delivery and improving the therapeutic effectiveness of MDR bacterial infections. Additionally, non-antibiotic antibacterial strategies based on nanomaterials, such as photothermal therapy and photodynamic therapy, are continuously being developed due to their non-invasive nature, high effectiveness, and non-induction of resistance. Therefore, multifunctional MNMs have broad prospects in the treatment of MDR bacterial infections. This review discusses the performance of MNMs in the breakthrough and elimination of bacterial biofilms, as well as their application in the field of anti-infection. Finally, the challenges and future development directions of antibacterial MNMs are introduced.}, } @article {pmid37875338, year = {2023}, author = {Marques Mendonca, R and Fulton, T and Blackwood, C and Costello, D}, title = {Sublethal nickel toxicity shuts off manganese oxidation and pellicle biofilm formation in Pseudomonas putida GB-1.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16529}, pmid = {37875338}, issn = {1462-2920}, support = {//the Kent State University Graduate Student Senate Research Award/ ; //the Kent State University Art and Margaret Herrick Endowment for the Aquatic Ecology Research Facility/ ; //the Society of Environmental Toxicology and Chemistry (SETAC) and the International Copper Association (ICA) Chris Lee Award for Metals Research/ ; }, abstract = {In sediments, the bioavailability and toxicity of Ni are strongly influenced by its sorption to manganese (Mn) oxides, which largely originate from the redox metabolism of microbes. However, microbes are concurrently susceptible to the toxic effects of Ni, which establishes complex interactions between toxicity and redox processes. This study measured the effect of Ni on growth, pellicle biofilm formation and oxidation of the Mn-oxidizing bacteria Pseudomonas putida GB-1. In liquid media, Ni exposure decreased the intrinsic growth rate but allowed growth to the stationary phase in all intermediate treatments. Manganese oxidation was 67% less than control for bacteria exposed to 5 μM Ni and completely ceased in all treatments above 50 μM. Pellicle biofilm development decreased exponentially with Ni concentration (maximum 92% reduction) and was replaced by planktonic growth in higher Ni treatments. In solid media assays, growth was unaffected by Ni exposure, but Mn oxidation completely ceased in treatments above 10 μM of Ni. Our results show that sublethal Ni concentrations substantially alter Mn oxidation rates and pellicle biofilm development in P. putida GB-1, which has implications for toxic metal bioavailability to the entire benthic community and the environmental consequences of metal contamination.}, } @article {pmid37875171, year = {2023}, author = {Qian, W and Yang, Y and Chou, S and Ge, S and Li, P and Wang, X and Zhuang, LL and Zhang, J}, title = {Effect of N/P ratio on attached microalgae growth and the differentiated metabolism along the depth of biofilm.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117428}, doi = {10.1016/j.envres.2023.117428}, pmid = {37875171}, issn = {1096-0953}, abstract = {Attached microalgae cultivation coupled with wastewater treatment could convert pollutants into bioresource with high efficiency and low cost. Nitrogen to phosphorus ratio (N/P ratio) is considered as an important factor on microalgae growth. Due to spatially heterogeneous distribution of nutrient, how N/P ratio affected attached microalgae growth in both macro- and micro-scopes was explored in this study. The findings revealed that an optimal N/P ratio of 10:1 promoted attached microalgae growth, while unsuitable ratios hampered algal growth by inhibiting photosynthesis, lowering oxidative resistance and decreasing metabolism activity. Long-term cultivation with improper N/P ratios resulted in a gradual decrease in actual photosynthetic rates, implying 50 days as the upper culture time limit for high-efficiency growth. Moreover, the study highlighted the uneven distribution of light and nutrients in algal biofilms, causing cells in different biofilm layers with variability of metabolism and composition. However, the [15]N isotopic distribution demonstrated that even bottom cells were equally capable of nitrogen assimilation.}, } @article {pmid37875431, year = {2023}, author = {Xiao, L and Feng, M and Chen, C and Xiao, Q and Cui, Y and Zhang, Y}, title = {Microenvironment-Regulating Drug Delivery Nanoparticles for Treating and Preventing Typical Biofilm-Induced Oral Diseases.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2304982}, doi = {10.1002/adma.202304982}, pmid = {37875431}, issn = {1521-4095}, support = {82025011//National Science Fund for Distinguished Young Scholars/ ; 82220108018//National Natural Science Foundation of China/ ; 2042022dx0003//Fundamental Research Funds for the Central Universities/ ; }, abstract = {The oral cavity comprises an environment full of microorganisms. Dysregulation of this microbial-cellular microenvironment will lead to a series of oral diseases, such as implant-associated infection caused by Staphylococcus aureus (S. aureus) biofilms and periodontitis initiated by Streptococcus oralis (S. oralis). In this study, a liposome-encapsulated indocyanine green (ICG) and rapamycin drug-delivery nanoparticle (ICG-rapamycin) is designed to treat and prevent two typical biofilm-induced oral diseases by regulating the microbial-cellular microenvironment. ICG-rapamycin elevates the reactive oxygen species (ROS) and temperature levels to facilitate photodynamic and photothermal mechanisms under near-infrared (NIR) laser irradiation for anti-bacteria. In addition, it prevents biofilm formation by promoting bacterial motility with increasing the ATP levels. The nanoparticles modulate the microbial-cellular interaction to reduce cellular inflammation and enhance bacterial clearance, which includes promoting the M2 polarization of macrophages, upregulating the anti-inflammatory factor TGF-β, and enhancing the bacterial phagocytosis of macrophages. Based on these findings, ICG-rapamycin is applied to implant-infected and periodontitis animal models to confirm the effects in vivo. This study demonstrates that ICG-rapamycin can treat and prevent biofilm-induced oral diseases by regulating the microbial-cellular microenvironment, thus providing a promising strategy for future clinical applications.}, } @article {pmid37873242, year = {2023}, author = {Byeon, CH and Kinney, T and Saricayir, H and Srinivasa, S and Wells, MK and Kim, W and Akbey, Ü}, title = {Tapping into the native Pseudomonas Bacterial Biofilm Structure by High-Resolution 1D and 2D MAS solid-state NMR.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.10.02.560490}, pmid = {37873242}, abstract = {We present a high-resolution 1D and 2D magic-angle spinning (MAS) solid-state NMR (ssNMR) study to characterize native Pseudomonas fluorescens colony biofilms at natural abundance without isotope-labelling. By using a high-resolution INEPT-based 2D [1] H- [13] C ssNMR spectrum and thorough peak deconvolution approach at the 1D ssNMR spectra, approximately 80/134 (in 1D/2D) distinct biofilm chemical sites were identified. We compared CP and INEPT [13] C ssNMR spectra to different signals originating from the mobile and rigid fractions of the biofilm, and qualitative determined dynamical changes by comparing CP buildup behaviors. Protein and polysaccharide signals were differentiated and identified by utilizing FapC signals as a template, a biofilm forming functional amyloid from Pseudomonas . We also attempted to identify biofilm polysaccharide species by using [1] H/ [13] C chemical shifts obtained from the 2D spectrum. This study marks the first demonstration of high-resolution 2D ssNMR spectroscopy for characterizing native bacterial biofilms and expands the scope of ssNMR in studying biofilms. Our experimental pipeline can be readily applied to other in vitro biofilm model systems and natural biofilms and holds the promise of making a substantial impact on biofilm research, fostering new ideas and breakthroughs to aid in the development of strategic approaches to combat infections caused by biofilm-forming bacteria.}, } @article {pmid37872187, year = {2023}, author = {Wala, SJ and Sajankila, N and Ragan, MV and Duff, AF and Wickham, J and Volpe, SG and Wang, Y and Conces, M and Dumbauld, Z and Purayil, N and Narayanan, S and Rajab, A and Mihi, B and Bailey, MT and Goodman, SD and Besner, GE}, title = {Superior performance of biofilm versus planktonic Limosilactobacillus reuteri in protection of the intestines and brain in a piglet model of necrotizing enterocolitis.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {17740}, pmid = {37872187}, issn = {2045-2322}, support = {R42GM122130/NH/NIH HHS/United States ; }, abstract = {Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal-related death in premature infants. Its etiology is multifactorial, with intestinal dysbiosis playing a major role. Probiotics are a logical preventative therapy for NEC, however their benefits have been inconsistent. We previously developed a novel probiotic delivery system in which planktonic (free-living) Limosilactobacillus reuteri (Lr) is incubated with biocompatible dextranomer microspheres (DM) loaded with maltose (Lr-DM-maltose) to induce biofilm formation. Here we have investigated the effects of Lr-DM-maltose in an enteral feed-only piglet model of NEC. We found a significant decrease in the incidence of Definitive NEC (D-NEC), death associated with D-NEC, and activated microglia in the brains of piglets treated with Lr-DM-maltose compared to non-treated piglets. Microbiome analyses using 16S rRNA sequencing of colonic contents revealed a significantly different microbial community composition between piglets treated with Lr-DM-maltose compared to non-treated piglets, with an increase in Lactobacillaceae and a decrease in Clostridiaceae in Lr-DM-maltose-treated piglets. Furthermore, there was a significant decrease in the incidence of D-NEC between piglets treated with Lr-DM-maltose compared to planktonic Lr. These findings validate our previous results in rodents, and support future clinical trials of Lr in its biofilm state for the prevention of NEC in premature neonates.}, } @article {pmid37871873, year = {2023}, author = {Ning, Z and Zhou, S and Li, P and Li, R and Liu, F and Zhao, Z and Ren, N and Lu, L}, title = {Exaggerated interaction of biofilm-developed microplastics and contaminants in aquatic environments.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140509}, doi = {10.1016/j.chemosphere.2023.140509}, pmid = {37871873}, issn = {1879-1298}, abstract = {Biofilm-developed microplastics (MPs) may serve as important vectors for contaminants in aquatic environments. Elucidating the interactions between biofilm-developed MPs and coexisting contaminants is crucial for understanding the vector capacities of MPs. However, little is known about how the adverse effects of contaminants on MP surface-colonized biofilms influence their vector capacity. In this study, we aimed to investigate the interaction mechanism of biofilms colonizing the surface of MPs with coexisting contaminants using microcosm experiments and biofilm characterization techniques. The results indicated that the biofilm biomass on polystyrene increased over time, providing an additional abundance of oxygen-containing functional groups and promoting Cd accumulation by biofilm-developed polystyrene. Moreover, as a coexisting contaminant, Cd exerted adverse effects such as additional mortality of microorganisms and senescence and MP-colonized biofilm shedding. Consequently, the contaminant vector capacity of biofilm-developed MPs could be mitigated. Thus, the adverse effects of coexisting contaminants on biofilms influenced the ability of MPs to act as vectors in aquatic environments. Neglecting the negative effects of contaminants on biofilms may lead to an overestimation of the contaminant vector capacity of biofilm-developed MPs. This study provides support for more accurate assessment of the interactions between biofilm-developed MPs as vectors and contaminants in aquatic environments.}, } @article {pmid37871301, year = {2023}, author = {Baburova, PI and Kladko, DV and Lokteva, A and Pozhitkova, A and Rumyantceva, V and Rumyantceva, V and Pankov, IV and Taskaev, S and Vinogradov, VV}, title = {Magnetic Soft Robot for Minimally Invasive Urethral Catheter Biofilm Eradication.}, journal = {ACS nano}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsnano.2c10127}, pmid = {37871301}, issn = {1936-086X}, abstract = {Catheter-related biofilm infection remains the main problem for millions of people annually, affecting morbidity, mortality, and quality of life. Despite the recent advances in the prevention of biofilm formation, alternative methods for biofilm prevention or eradication still should be found to avoid traumatic and expensive removal or catheter replacement. Soft magnetic robots have drawn significant interest in favor of remote control, fast response, and wide space for design. In this work, we demonstrated magnetic soft robots as a minimally invasive, safe, and effective approach to eliminate biofilm from urethral catheters (20 Fr or 5.1 mm in diameter). Seven designs of the robot were fabricated (size 4.5 × 15 mm), characterized, and tested in the presence of a rotating magnetic field. As a proof-of-concept, we demonstrated the superior efficiency of biofilm removal on the model of a urethral catheter using a magnetic robot, reaching full eradication for the octagram-shaped robot (velocity 2.88 ± 0.6 mm/s) at a 15 Hz frequency and a 10 mT amplitude. These findings are helpful for the treatment of biofilm-associated catheter contamination, which allows an increase in the catheter wearing time without frequent replacement and treatment of catheter-associated infections.}, } @article {pmid37871028, year = {2023}, author = {Myckatyn, TM and Duran Ramirez, JM and Walker, JN and Hanson, BM}, title = {Management of Biofilm with Breast Implant Surgery.}, journal = {Plastic and reconstructive surgery}, volume = {152}, number = {5}, pages = {919e-942e}, doi = {10.1097/PRS.0000000000010791}, pmid = {37871028}, issn = {1529-4242}, abstract = {LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand how bacteria negatively impact aesthetic and reconstructive breast implants. 2. Understand how bacteria infect breast implants. 3. Understand the evidence associated with common implant infection-prevention strategies, and their limitations. 4. Understand why implementation of bacteria-mitigation strategies such as antibiotic administration or "no-touch" techniques may not indefinitely prevent breast implant infection.

SUMMARY: Bacterial infection of aesthetic and reconstructive breast implants is a common and expensive problem. Subacute infections or chronic capsular contractures leading to device explantation are the most commonly documented sequelae. Although bench and translational research underscores the complexities of implant-associated infection, high-quality studies with adequate power, control groups, and duration of follow-up are lacking. Common strategies to minimize infections use antibiotics-administered systemically, in the breast implant pocket, or by directly bathing the implant before insertion-to limit bacterial contamination. Limiting contact between the implant and skin or breast parenchyma represents an additional common strategy. The clinical prevention of breast implant infection is challenged by the clean-contaminated nature of breast parenchyma, and the variable behavior of not only specific bacterial species but also their strains. These factors impact bacterial virulence and antibiotic resistance.}, } @article {pmid37869725, year = {2024}, author = {Yang, J and Huang, Z and Tan, J and Pan, J and Chen, S and Wan, W}, title = {Copper ion/gallic acid MOFs-laden adhesive pomelo peel sponge effectively treats biofilm-infected skin wounds and improves healing quality.}, journal = {Bioactive materials}, volume = {32}, number = {}, pages = {260-276}, pmid = {37869725}, issn = {2452-199X}, abstract = {Bacterial infection and scar formation remain primary challenges in wound healing. To address these issues, we developed a decellularized pomelo peel (DPP) functionalized with an adhesive PVA-TSPBA hydrogel and antibacterial gallic acid/copper MOFs. The hybrid wound dressing demonstrates favorable biocompatibility. It does not impede the proliferation of fibroblasts or immune cells and can stimulate fibroblast migration, endothelial angiogenesis, and M2 macrophage polarization. Additionally, the dressing can scavenge reactive oxygen species (ROS) and provide antioxidant effects. Furthermore, DPP + MOF@Gel effectively inhibits the viability of S. aureus and E. coli in vitro and in vivo. The histological observations revealed enhanced granulation tissue formation, re-epithelialization, and angiogenesis in the DPP + MOF@Gel group compared to other groups. The local immune response also shifted from a pro-inflammatory to a pro-regenerative status with DPP + MOF@Gel treatment. The skin incision stitching experiment further exhibits DPP + MOF@Gel could reduce scar formation during wound healing. Taken together, the hybrid DPP + MOF@Gel holds great promise for treating bacteria-infected skin wounds and inhibiting scar formation during wound healing.}, } @article {pmid37869592, year = {2023}, author = {Bajelani, S and Enayatizamir, N and Agha, ABA and Sharifi, R}, title = {Potential of some microbial isolates on diesel hydrocarbons removal, bio surfactant production and biofilm formation.}, journal = {Journal of environmental health science & engineering}, volume = {21}, number = {2}, pages = {417-428}, pmid = {37869592}, issn = {2052-336X}, abstract = {Potential of Arthrobacter citreus B27Pet, Bacillus thuringiensis B48Pet and Candida catnulata to produce biosurfactant using four different carbon sources (naphthalene, hexadecane, diesel and petroleum crude oil) was investigated. Removal of petroleum crude oil from aqueous culture and degradation of diesel were also determined using single and mixed culture of strains. The biofilm existence in single and mixed culture of strains was considered using naphthalene, hexadecane and diesel in culture medium. Cell surface hydrophobicity of A. citreus was higher than other isolates which also showed maximum surface tension reduction and emulsification index. As a whole, remarkable biosurfactant production occurred using petroleum crude oil as a carbon source in medium. A. citreus was found to be more robust than other tested strains in removal efficiency of crude oil due to its biosurfactant production capability. Statistically significant positive correlation was observed between biofilm existence and surface tension using diesel and hexadecane as carbon source. Overall diesel biodegradation efficiency by the mix culture of three applied strains was about 75% within a short period of time (10 days) which was accompanied with high biofilm production.}, } @article {pmid37868553, year = {2023}, author = {Palandurkar, GS and Kumar, S}, title = {Biofilm's Impact on Inflammatory Bowel Diseases.}, journal = {Cureus}, volume = {15}, number = {9}, pages = {e45510}, pmid = {37868553}, issn = {2168-8184}, abstract = {The colon has a large surface area covered with a thick mucus coating. Colon's biomass consists of about 1,012 colony-forming units per gram of feces and 500-1,000 distinct bacterial species. The term inflammatory bowel disease (IBD) indicates the collection of intestinal illnesses in which the digestive system (esophagus, large intestine, mouth, stomach, and small intestine) experiences persistent inflammation. IBD development is influenced by environmental (infections, stress, and nutrition) and genetic factors. The microbes present in gut microbiota help maintain intestinal homeostasis and support immune and epithelial cell growth, differentiation, as well as proliferation. It has been discovered that a variety of variables and microorganisms are crucial for the development of biofilms and mucosal colonization during IBD. An extracellular matrix formed by bacteria supports biofilm production in our digestive system and harms the host's immunological response. Irritable bowel syndrome (IBS) and IBD considerably affect human socioeconomic well-being and the standard of living. IBD is a serious public health issue, affecting millions of people across the globe. The gut microbiome may significantly influence IBS pathogenesis, even though few diagnostic and treatment options are available. As a result, current research focuses more on disrupting biofilm in IBD patients and stresses primarily on drugs that help improve the quality of life for human well-being. We evaluate studies on IBD and bacterial biofilm to add fresh insights into the existing state of knowledge of biofilm formation in IBD, incidence of IBD patients, molecular level of investigations, bacteria that are involved in the formation of biofilm, and present and down the line regimens and probiotics. Planning advanced ways to control and eradicate bacteria in biofilms should be the primary goal to add fresh insights into generating innovative diagnostic and alternative therapy options for IBD.}, } @article {pmid37868332, year = {2023}, author = {Rodríguez-Suárez, JM and Gershenson, A and Onuh, TU and Butler, CS}, title = {The Heterogeneous Diffusion of Polystyrene Nanoparticles and the Effect on the Expression of Quorum-Sensing Genes and EPS Production as a Function of Particle Charge and Biofilm Age.}, journal = {Environmental science. Nano}, volume = {10}, number = {9}, pages = {2551-2565}, pmid = {37868332}, issn = {2051-8153}, abstract = {Biofilms are abundantly present in both natural and engineered environmental systems and will likely influence broader particle fate and transport phenomena. While some developed models describe the interactions between nanoparticles and biofilms, studies are only beginning to uncover the complexity of nanoparticle diffusion patterns. With the knowledge of the nanoparticle potential to influence bacterial processes, more systematic studies are needed to uncover the dynamics of bacteria-nanoparticle interactions. This study explored specific microbial responses to nanoparticles and the heterogeneity of nanoparticle diffusion. Pseudomonas aeruginosa biofilms (cultivated for 48 and 96 hours, representing early and late stages of development) were exposed to charged (aminated and carboxylated) polystyrene nanoparticles. With a combination of advanced fluorescence microscopy and real time quantitative PCR, we characterized the diffusion of polystyrene nanoparticles in P. aeruginosa biofilms and evaluated how biofilms respond to the presence of nanoparticles in terms of the expression of key EPS production-associated genes (pelA and rpsL) and quorum-sensing associated (lasR) genes. Our findings show that nanoparticle diffusion coefficients are independent of the particle surface charge only in mature biofilms and that the presence of nanoparticles influences bacterial gene expression. Independent of the particle's charge polystyrene nanoparticles down-regulated pelA in mature biofilms. By contrast, charge-specific responses were identified in lasR and rpsL gene expression. The targeted genes expression analysis and heterogeneous diffusion models demonstrate that particle charge influences nanoparticle mobility and provides significant insight into the intrinsic structural heterogeneity of P. aeruginosa biofilms. These findings suggest that biofilm maturity and particle charge are essential factors to consider when evaluating the transport of nanoparticles within a biofilm matrix.}, } @article {pmid37868294, year = {2023}, author = {Khawwam, SI and Al-Groosh, DH}, title = {Effect of Different Cleaning Regimes on Biofilm Formation of Acrylic-Based Removable Orthodontic Appliance: A Randomized Clinical Trial.}, journal = {TheScientificWorldJournal}, volume = {2023}, number = {}, pages = {9920850}, pmid = {37868294}, issn = {1537-744X}, abstract = {OBJECTIVES: This study aimed to evaluate the effects of different cleaning regimes of acrylic-based removable orthodontic appliances on bacterial biofilm formation and whether the surface modification, i.e., polished acrylic fitting surface, reduces biofilm formation.

MATERIALS AND METHODS: This double-blind, parallel, randomized clinical trial involved thirty-nine orthodontic patients indicated for removable orthodontic appliances. The patients were allocated into three groups according to the cleaning method: brushing with a denture brush and chlorhexidine (CHX) toothpaste, Lacalut cleaning tablet, and a combination of both cleaning methods. Each patient wore an upper removable appliance containing eight wells fitted with eight detachable acrylic tiles (four polished and four unpolished) for seven days. Five types of oral microbiota were evaluated using selective growth media and biochemical tests. The biofilm cleaning efficacy was assessed using the colony-forming unit (CFU) and scanning electron microscopy (SEM). Statistical Analysis. Data from the CFU using different cleansing regimes were compared, following log transformation, using one-way analysis of variance (ANOVA). The polished and unpolished tiles were compared for biofilm formation on each cleansing method using an independent t-test.

RESULTS: There was no significant difference among the three cleaning methods on the polished or unpolished tiles. However, in polished tiles, streptococci were significantly reduced in all cleaning methods, whereas staphylococci and Staphylococcus aureus were markedly decreased in brushing and combination cleaning methods. However, the total number of anaerobic bacteria was significantly reduced in polished tiles using the combination method only.

CONCLUSIONS: Polishing the fitting surface of an acrylic-based orthodontic appliance reduced the tested bacterial biofilm formation and may enhance cleaning efficiency. Brushing and combination methods showed superior cleaning effects compared to cleaning tablets. This trial is registered with NCT05707221.}, } @article {pmid37867806, year = {2023}, author = {Trang, PN and Anh Ngoc, TT and Masuda, Y and Hohjoh, KI and Miyamoto, T}, title = {Antimicrobial resistance and biofilm formation of Escherichia coli in a Vietnamese Pangasius fish processing facility.}, journal = {Heliyon}, volume = {9}, number = {10}, pages = {e20727}, pmid = {37867806}, issn = {2405-8440}, abstract = {This study aimed to investigate the occurrence, antibiotic resistance, and biofilm formation of Escherichia coli in the Vietnamese Pangasius fish processing facility. Among 144 samples including Pangasius fish, wash water, food contact surfaces, and personnel gloves, 18 E. coli isolates was detected and characterized. The E. coli was detected most frequently in wash water samples (22%, 8/36), followed by Pangasius fish (18%, 8/45). According to the antibiotic susceptibility test by the disc diffusion method, isolates showed the highest resistance against sulfamethoxazole/trimethoprim (45%), followed by tetracycline (39%), whereas all the E. coli isolates were susceptible to meropenem and fosfomycin. Notably, 39% of the isolates (7/18) were found to be multidrug resistant while no E. coli isolates were confirmed as extended-spectrum β-lactamase producers by the double-disk synergy test. The potency to form biofilm on the polystyrene surface of E. coli isolates indicated that 44% of the isolates (8/18) were classified as weak, 39% (7/18) as moderate, and 17% (3/18) as strong biofilm formers. Interestingly, multidrug resistant E. coli isolates were observed in moderate and strong biofilm producers. Additionally, either slightly acidic hypochlorous water with 40 mg/L of available chlorine or sodium hypochlorite with 100 mg/L of available chlorine exhibited a significant reduction in biofilm mass and biofilm cells of E. coli isolates. This study may provide helpful information about the actual state of E. coli isolates for effective control in the fish processing plant.}, } @article {pmid37867724, year = {2023}, author = {Roy, S and Acosta, JAM and Karak, M and Ramirez-Velez, I and Torikai, K and Ren, D and Barbosa, LCA}, title = {Effects of Synthetic Tetronamides and Methylated Denigrins on Bacterial Quorum Sensing and Biofilm Formation.}, journal = {ACS omega}, volume = {8}, number = {41}, pages = {37798-37807}, pmid = {37867724}, issn = {2470-1343}, abstract = {Detrimental biofilms of bacterial pathogens cause chronic infections with a high-level tolerance to antibiotics. To identify new control agents, we synthesized and tested a total of 14 tetronamides (including 5 new compounds) and 6 denigrin intermediates on the model species Escherichia coli. At a concentration of 50 μg/mL, two tetronamides and two methylated denigrins exhibited significant inhibitory effects against biofilm formation of E. coli RP437, e.g., by 60 and 94%, respectively. Structural analysis of the tested compounds revealed that p-methoxybenzylidene and p-methoxyphenethyl moieties of denigrins are important for biofilm inhibition, while the former group is also essential to the activity against quorum sensing (QS) via AI-2. Specifically, tetramethyldenigrin B has strong inhibitory effects against both E. coli biofilm formation and AI-2-mediated QS and thus provides a promising lead structure for designing better control agents. Consistently, tetramethyldenigrin B also showed inhibitory activity against biofilm formation of uropathogenic E. coli. Together, these findings provide new insights for the rational design of novel biofilm and QS inhibitors.}, } @article {pmid37866577, year = {2023}, author = {Rashki, S and Dawi, EA and Zilaei, MR and Safardoust-Hojaghan, H and Ghanbari, M and Ryadh, A and Lafta, HA and Khaledi, A and Salavati-Niasari, M}, title = {ZnO/chitosan nanocomposites as a new approach for delivery LL37 and evaluation of the inhibitory effects against biofilm-producing Methicillin-resistant Staphylococcus aureus isolated from clinical samples.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127583}, doi = {10.1016/j.ijbiomac.2023.127583}, pmid = {37866577}, issn = {1879-0003}, abstract = {Modification surface of chitosan nanoparticles using ZnO nanoparticles is important interest in drug delivery because of the beneficial properties. In this study, we proposed a chitosan/ZnO nanocomposite for the targeted delivery of antibacterial peptide (LL37). Synthesized LL37-loaded chitosan/ZnO nanocomposite (CS/ZnO/LL37-NCs) was based on the ionotropic gelation method. The antibacterial activity of the synthesized platform versus Methicillin-resistant Staphylococcus aureus (MRSA) was determined by the microdilution method in 10 mM sodium phosphate buffer. The biofilm formation inhibitory was also evaluated using microtiter plate method. In addition, the ability of CS/ZnO/LL37-NCs on the icaA gene expression level was assessed by the Real-Time PCR. The loading and release investigations confirmed the suitability of CS/ZnO-NCs for LL37 encapsulation. Results showed 6 log10 CFU/ml reduction in MRSA treated with the CS/ZnO/LL37-NPs. Moreover, CS/ZnO/LL37-NCs showed 81 % biofilm formation inhibition than LL37 alone. Also, icaA gene expression decreased 1-fold in the face of CS/ZnO/LL37-NCs. In conclusion, the modification surface of chitosan nanoparticles with ZnO nanoparticles is a suitable chemical platform for the delivery of LL37 that could be used as a promising nanocarrier for enhancing the delivery of antibacterial peptide and improving the antibacterial activity of LL37.}, } @article {pmid37866335, year = {2023}, author = {Hassan, RM and Abd El-Maksoud, MS and Ghannam, IAY and El-Azzouny, AA and Aboul-Enein, MN}, title = {Synthetic non-toxic anti-biofilm agents as a strategy in combating bacterial resistance.}, journal = {European journal of medicinal chemistry}, volume = {262}, number = {}, pages = {115867}, doi = {10.1016/j.ejmech.2023.115867}, pmid = {37866335}, issn = {1768-3254}, abstract = {The tremendous increase in the bacterial resistance to the available antibiotics is a serious problem for the treatment of various infections. Biofilm formation in bacteria significantly contributes to the bacterial survival in host cells, and is considered as an crucial factor, responsible for bacterial resistance. The response of the bacterial cells in the biofilm to antibiotics is completely different from that of the free floating planktonic cells of the same strain. The anti-biofilm agents that could inhibit the biofilm production without affecting the bacterial growth, apply less selective pressure over the bacterial strains than the traditional antibiotics; thus the development of bacterial resistance would be of low incidence. Many attempts have been performed to discover novel agents capable of interfering with the bacterial biofilm life cycle, and several compounds have shown promising activities in suppressing the biofilm production or in dispersing mature existing biofilms. This review describes the different chemical classes that have anti-biofilm effects against different Gram-positive and Gram-negative bacteria without affecting the bacterial growth.}, } @article {pmid37866187, year = {2023}, author = {Wu, Q and Chen, Y and He, Y and Cheng, Q and Wu, Q and Liu, Z and Li, Y and Yang, Z and Tan, Y and Yuan, Y}, title = {Enhanced nitrogen and phosphorus removal by a novel ecological floating bed integrated with three-dimensional biofilm electrode system.}, journal = {Journal of environmental management}, volume = {348}, number = {}, pages = {119346}, doi = {10.1016/j.jenvman.2023.119346}, pmid = {37866187}, issn = {1095-8630}, abstract = {The ecological floating bed (EFB) has been used extensively for the purification of eutrophication water. However, the traditional EFB (T-EFB) often exhibits a decline in nitrogen and phosphorus removal because of the limited adsorption capacity of fillers and inadequate electron donors. In the present study, a series of electrolysis-ecological floating beds (EC-EFBs) were constructed to investigate the decontamination performance of conventional pollutants. EC-EFB outperformed T-EFB in terms of nitrogen and phosphorus removal. Its removal efficiency of total nitrogen and total phosphorus was 20.51-32.95% and 45.06-96.20%, which were higher than that in T-EFB.. Moreover, the plants in EC-EFB demonstrated higher metabolic activity than those in T-EFB. Under the electrolysis condition of 0.51 mA/cm[2] for 24 h, the malondialdehyde content and superoxide dismutase activity in EC-EFB were 6.08 nmol/g and 22.61 U/g, which were significantly lower compared to T-EFB (38.65 nmol/g and 26.13 U/g). And the soluble protein content of plant leaves increased from 3.31 mg/g to 5.72 mg/g in EC-EFB. Microbial analysis revealed that electrolysis could significantly change the microbial community and facilitate the proliferation of nitrogen-functional microbes, such as Thermomonas, Hydrogenophaga, Deinococcus, and Zoogloea. It is important to highlight that the hydrogen evolution reaction at the cathode area facilitated phosphorus removal in EC-EFB, thereby inhibiting phosphorus leaching. This study provides a promising and innovative technology for the purification of eutrophic water.}, } @article {pmid37866051, year = {2023}, author = {Zhang, J and Zhang, HY and Xu, WR and Zhang, YC}, title = {Sustainable biomass-based composite biofilm: Sodium alginate, TEMPO-oxidized chitin nanocrystals, and MXene nanosheets for fire-resistant materials and next-generation sensors.}, journal = {Journal of colloid and interface science}, volume = {654}, number = {Pt A}, pages = {795-804}, doi = {10.1016/j.jcis.2023.10.080}, pmid = {37866051}, issn = {1095-7103}, abstract = {Efficient utilization of natural biomass for the development of fireproof materials and next-generation sensors faces various challenges in the field of fire safety and prevention. In this study, renewable sodium alginate (SA), TEMPO-oxidized chitin nanocrystals (TOChNs), and MXene nanosheets were employed to fabricate a sustainable, flexible, and flame-retardant composite biofilm, donated as STM, utilizing a simple and environmentally friendly evaporation-induced self-assembly technique. The incorporation of SA, TOChNs, and MXene in a weight ratio of 50/10/40 led to improved mechanical properties of the resulting STM-40 films, as evidenced by increased tensile strength and Young's modulus values of approximately 36 MPa and 4 GPa, respectively. Notably, these values were approximately 3 and 11 times higher than those observed for the pure SA film. Moreover, the STM-40 films demonstrated highly sensitive fire alarm capabilities, exhibiting a superior flame alarm response time of 0.6 s and a continuous alarm time of approximately 492 s when exposed to flames. The STM exhibited exceptional flame retardancy due to the synergistic carbonization between MXene and SA/TOChNs, resulting in a limiting oxygen index of 45.0 %. Furthermore, its maximum heat release rate decreased by over 90.1 % during the test. This study presents a novel approach for designing and developing fire-retardant fire alarm sensors by utilizing natural biomass.}, } @article {pmid37865090, year = {2023}, author = {Mishra, R and Hannebelle, M and Patil, VP and Dubois, A and Garcia-Mouton, C and Kirsch, GM and Jan, M and Sharma, K and Guex, N and Sordet-Dessimoz, J and Perez-Gil, J and Prakash, M and Knott, GW and Dhar, N and McKinney, JD and Thacker, VV}, title = {Mechanopathology of biofilm-like Mycobacterium tuberculosis cords.}, journal = {Cell}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cell.2023.09.016}, pmid = {37865090}, issn = {1097-4172}, abstract = {Mycobacterium tuberculosis (Mtb) cultured axenically without detergent forms biofilm-like cords, a clinical identifier of virulence. In lung-on-chip (LoC) and mouse models, cords in alveolar cells contribute to suppression of innate immune signaling via nuclear compression. Thereafter, extracellular cords cause contact-dependent phagocyte death but grow intercellularly between epithelial cells. The absence of these mechanopathological mechanisms explains the greater proportion of alveolar lesions with increased immune infiltration and dissemination defects in cording-deficient Mtb infections. Compression of Mtb lipid monolayers induces a phase transition that enables mechanical energy storage. Agent-based simulations demonstrate that the increased energy storage capacity is sufficient for the formation of cords that maintain structural integrity despite mechanical perturbation. Bacteria in cords remain translationally active despite antibiotic exposure and regrow rapidly upon cessation of treatment. This study provides a conceptual framework for the biophysics and function in tuberculosis infection and therapy of cord architectures independent of mechanisms ascribed to single bacteria.}, } @article {pmid37860966, year = {2023}, author = {Sun, WS and Lassinantti, L and Järvå, M and Schmitt, A and Ter Beek, J and Berntsson, RP}, title = {Structural foundation for the role of enterococcal PrgB in conjugation, biofilm formation, and virulence.}, journal = {eLife}, volume = {12}, number = {}, pages = {}, pmid = {37860966}, issn = {2050-084X}, support = {2016-03599//Vetenskapsrådet/ ; SMK-1762//Kempestiftelserna/ ; SMK-1869//Kempestiftelserna/ ; CTS 18:39//Carl Tryggers Stiftelse för Vetenskaplig Forskning/ ; }, abstract = {Type 4 Secretion Systems are a main driver for the spread of antibiotic resistance genes and virulence factors in bacteria. In Gram-positives, these secretion systems often rely on surface adhesins to enhance cellular aggregation and mating-pair formation. One of the best studied adhesins is PrgB from the conjugative plasmid pCF10 of Enterococcus faecalis, which has been shown to play major roles in conjugation, biofilm formation, and importantly also in bacterial virulence. Since prgB orthologs exist on a large number of conjugative plasmids in various different species, this makes PrgB a model protein for this widespread virulence factor. After characterizing the polymer adhesin domain of PrgB previously, we here report the structure for almost the entire remainder of PrgB, which reveals that PrgB contains four immunoglobulin (Ig)-like domains. Based on this new insight, we re-evaluate previously studied variants and present new in vivo data where specific domains or conserved residues have been removed. For the first time, we can show a decoupling of cellular aggregation from biofilm formation and conjugation in prgB mutant phenotypes. Based on the presented data, we propose a new functional model to explain how PrgB mediates its different functions. We hypothesize that the Ig-like domains act as a rigid stalk that presents the polymer adhesin domain at the right distance from the cell wall.}, } @article {pmid37860516, year = {2023}, author = {Kokila, V and Prasanna, R and Kumar, A and Nishanth, S and Singh, B and Gaur Rudra, S and Pal, P and Pal, M and Shivay, YS and Singh, AK}, title = {Elevated CO2 along with inoculation of cyanobacterial biofilm or its partners differentially modulates C-N metabolism and quality of tomato beneficially.}, journal = {Heliyon}, volume = {9}, number = {10}, pages = {e20470}, pmid = {37860516}, issn = {2405-8440}, abstract = {Diazotrophic cyanobacteria are known to influence nutrient availability in soil, however, their benefits under elevated CO2 environment, particularly on fruit quality attributes, is a less investigated aspect. Laboratory developed cyanobacterium-fungal biofilm (An-Tr), composed of Anabaena torulosa (An) as the matrix with the partner as Trichoderma viride (Tr), along with the individual partners were evaluated under ambient (aCO2-400 ± 50 ppm) and elevated (eCO2-700 ± 50 ppm) conditions, with and without tomato plants. An-Tr inoculation exhibited distinct and significantly higher values for most of the soil microbiological parameters, plant growth attributes and antioxidant/defense enzyme activities measured at 30 and 60 DAI (days after inoculation). Significant enhancement in soil nutrient availability, leaf chlorophyll, with 45-50% increase in the enzyme activities related to carbon and nitrogen assimilation, higher yields and better-quality parameters of tomato, with An-Tr biofilm or An inoculation, were recorded, particularly under eCO2 conditions. The fruits from An-Tr treatments under eCO2 exhibited a higher titrable acidity, along with more ascorbic acid, carotenoids and lycopene content, highlighting the superiority of this inoculant. Multivariate analyses revealed significant (p ≤ 0.05) interactions among cultures, DAI, and CO2 levels, illustrating that cyanobacterial inoculation can be advocated as a strategy to gainfully sequester eCO2. Significant improvement in yield and fruit quality along with 50% N savings, further attest to the promise of cyanobacterial inoculants for tomato crop in the climate change scenario.}, } @article {pmid37859795, year = {2023}, author = {Abadikhah, M and Liu, M and Persson, F and Wilén, BM and Farewell, A and Sun, J and Modin, O}, title = {Effect of anode material and dispersal limitation on the performance and biofilm community in microbial electrolysis cells.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100161}, pmid = {37859795}, issn = {2590-2075}, abstract = {In a microbial electrolysis cell (MEC), the oxidization of organic compounds is facilitated by an electrogenic biofilm on the anode surface. The biofilm community composition determines the function of the system. Both deterministic and stochastic factors affect the community, but the relative importance of different factors is poorly understood. Anode material is a deterministic factor as materials with different properties may select for different microorganisms. Ecological drift is a stochastic factor, which is amplified by dispersal limitation between communities. Here, we compared the effects of three anode materials (graphene, carbon cloth, and nickel) with the effect of dispersal limitation on the function and biofilm community assembly. Twelve MECs were operated for 56 days in four hydraulically connected loops and shotgun metagenomic sequencing was used to analyse the microbial community composition on the anode surfaces at the end of the experiment. The anode material was the most important factor affecting the performance of the MECs, explaining 54-80 % of the variance observed in peak current density, total electric charge generation, and start-up lag time, while dispersal limitation explained 10-16 % of the variance. Carbon cloth anodes had the highest current generation and shortest lag time. However, dispersal limitation was the most important factor affecting microbial community structure, explaining 61-98 % of the variance in community diversity, evenness, and the relative abundance of the most abundant taxa, while anode material explained 0-20 % of the variance. The biofilms contained nine Desulfobacterota metagenome-assembled genomes (MAGs), which made up 64-89 % of the communities and were likely responsible for electricity generation in the MECs. Different MAGs dominated in different MECs. Particularly two different genotypes related to Geobacter benzoatilyticus competed for dominance on the anodes and reached relative abundances up to 83 %. The winning genotype was the same in all MECs that were hydraulically connected irrespective of anode material used.}, } @article {pmid37859691, year = {2023}, author = {Roy, S and Gow, NAR}, title = {The role of the Candida biofilm matrix in drug and immune protection.}, journal = {Cell surface (Amsterdam, Netherlands)}, volume = {10}, number = {}, pages = {100111}, pmid = {37859691}, issn = {2468-2330}, } @article {pmid37859380, year = {2023}, author = {Hu, RX and Su, J}, title = {[Removal effect of disinfection factors in low concentration on Pseudomonas aeruginosa biofilm].}, journal = {Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]}, volume = {57}, number = {10}, pages = {1620-1624}, doi = {10.3760/cma.j.cn112150-20221213-01199}, pmid = {37859380}, issn = {0253-9624}, support = {XMLX201850//Clinical Technology Innovation Project of Beijing Municipal Administration of Hospitals Clinical Medicine Development-Study on the Continuous Disinfection Effect and Application Safety of Iodinated Resin on Dental Unit Waterlines/ ; }, abstract = {Experimental model of Pseudomonas aeruginosa biofilm was established in vitro by using biofilm reactor. The aim of this study was evaluating the removal effect of two kinds of water flowing through bactericide resin on Pseudomonas aeruginosa biofilm, and exploring the effectiveness of continuous treatment with low concentration disinfection factor on dental unit waterlines. The experimental group selected 1-2 mg/L iodinated resin (IR) filtered water and bromined hydantoin resin (BHR) filtered water with the control group selecting the sterile distilled water. Biofilms were treated by using the immersion method for 3, 7, 10, 20, and 40 days. Total viable count (TVC) and laser confocal microscopy method (CLSM) were selected to evaluate the biofilm removal effect. The result of TVC showed that in group IR, the bacterial clearance after the treatment of 3, 7, 10, and 20 days was lower than 99.9% and unqualified. The bacterial clearance after the treatment of 40 days was 99.9%,which is qualified. In group BHR, it was lower than 99.9% and unqualified after the treatment of 3, 7, and 10 days. It was and 99.99%, 100.00% after the treatment of 20, 40 days, respectively. The result of CLSM showed that before treatment, Pseudomonas aeruginosa biofilm showed a sheet and mass distribution. The bacterial coverage was 19.24%±1.97%. The proportion of viable bacteria was 93.91%±1.39%, and the biofilm matrix coverage was 17.69%±1.11%. After 20 days of treatment, the biofilm was decreased in the IR group, with the biofilm bacterial coverage reducing to 6.77%±1.61%, the proportion of live bacteria reducing to 54.85%±5.65%, and the biofilm matrix coverage reducing to 2.41%±0.85%.There was significant difference from the pre-treatment and the control (F=359.996,P<0.001). No biofilm-like structure was found in the BHR group. After 40 days of treatment, there was still a small amount of biofilm matrix residue in the IR group, with no bacterial coverage observed. The biofilm matrix coverage was 0.67%±0.47% (F=1 021.373,P<0.001). No biofilm-like structure was found in the BHR group. In conclusion, the continuous application of BHR filter water has more advantages in killing microorganisms in biofilms, removing live and dead bacteria and biofilm matrix in biofilms. Treatment water containing corresponding low concentration disinfection factors can play an important role in the field of biofilm control in dental unit waterlines.}, } @article {pmid37857249, year = {2023}, author = {Jurado, P and Uruén, C and Martínez, S and Lain, E and Sánchez, S and Rezusta, A and López, V and Arenas, J}, title = {Essential oils of Pinus sylvestris, Citrus limon and Origanum vulgare exhibit high bactericidal and anti-biofilm activities against Neisseria gonorrhoeae and Streptococcus suis.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {168}, number = {}, pages = {115703}, doi = {10.1016/j.biopha.2023.115703}, pmid = {37857249}, issn = {1950-6007}, abstract = {Antimicrobial resistance is a worldwide problem that urges novel alternatives to treat infections. In attempts to find novel molecules, we assess the antimicrobial potential of seven essential oils (EO) of different plants (Pinus sylvestris, Citrus limon, Origanum vulgare, Cymbopogon martini, Cinnamomum cassia, Melaleuca alternifolia and Eucalyptus globulus) against two multidrug-resistant bacteria species, i.e. Neisseria gonorrhoeae and Streptococcus suis. EOs of P. sylvestris and C. limon revealed higher bactericidal activity (MIC ≤ 0.5 mg/mL) and capacity to rapidly disperse biofilms of several N. gonorrhoeae clinical isolates than other EOs. Examination of biofilms exposed to both EO by electron microscopy revealed a reduction of bacterial aggregates, high production of extracellular vesicles, and alteration of cell integrity. This activity was dose-dependent and was enhanced in DNase I-treated biofilms. Antibiotic susceptibility studies confirmed that both EOs affected the outer membrane permeability, and analysis of EO- susceptibility of an LPS-deficient mutant suggested that both EO target the LPS bilayer. Further analysis revealed that α- and β-pinene and d-limonene, components of both EO, contribute to such activity. EO of C. martini, C. cassia, and O. vulgare exhibited promising antimicrobial activity (MIC ≤ 0.5 mg/mL) against S. suis, but only EO of O. vulgare exhibited a high biofilm dispersal activity, which was also confirmed by electron microscopy studies. To conclude, the EO of P. sylvestris, C. limon and O. vulgare studied in this work exhibit bactericidal and anti-biofilm activities against gonococcus and streptococcus, respectively.}, } @article {pmid37857227, year = {2023}, author = {Velázquez-Moreno, S and Zavala-Alonso, NV and Oliva Rodríguez, R and Quintana, M and Ojeda-Galván, HJ and Gonzalez-Ortega, O and Martinez-Gutierrez, F}, title = {Multispecies oral biofilm and identification of components as treatment target.}, journal = {Archives of oral biology}, volume = {156}, number = {}, pages = {105821}, doi = {10.1016/j.archoralbio.2023.105821}, pmid = {37857227}, issn = {1879-1506}, abstract = {UNLABELLED: Endodontic infections involve a multispecies biofilm, making it difficult to choose an antimicrobial treatment. Characteristics such as the pathogens involved and number of microorganisms, nutrients, material surface to develop the biofilm, flow and oxygenation conditions are important for biofilm development using in vitro models.

OBJECTIVE: To develop a standardized biofilm model, which replicates the main features (chemical, microbiological, and topographical) of an infected root canal tooth to detect components as treatment target.

DESIGN: Clinical strains of Enterococcus faecalis, Candida albicans, and Actinomyces israelii were isolated, and a multispecies biofilm was developed using continuous laminar flow reactors under anaerobic conditions in human dental roots. The microbiological composition was determined by counting colony-forming units and scanning electron microscope micrographs. In addition, the chemical composition of the exopolymeric matrix was determined by vibrational Raman spectroscopy and liquid chromatography of biofilm supernatant treated with enzyme.

RESULTS: E. faecalis turned out to be the main microorganism in mature biofilm, this was related to the presence of β-galactosidase detected by vibrational Raman spectroscopy. After the enzymatic treatment of the extracellular polymeric substance, the presence of mannose and glucose was established.

CONCLUSIONS: The present work contributes to better understanding of standard conditions to develop a multispecies biofilm in human dental roots, which could have an impact on the generation of new root canal disinfection techniques in endodontic pathologies.}, } @article {pmid37857020, year = {2023}, author = {Wang, Y and Ling, N and Wang, Y and Ou, D and Liang, Z and Li, G and Zhao, H and Ye, Y}, title = {Effect of ferric ions on Cronobacter sakazakii growth, biofilm formation, and swarming motility.}, journal = {International journal of food microbiology}, volume = {408}, number = {}, pages = {110418}, doi = {10.1016/j.ijfoodmicro.2023.110418}, pmid = {37857020}, issn = {1879-3460}, abstract = {Cronobacter sakazakii (C. sakazakii) is a common food-borne pathogen that induces meningitis, sepsis, and necrotizing enterocolitis, primarily in newborns and infants. Iron plays a pivotal role in the growth of cells and biofilm formation. However, the effects of hemin (ferric ion donor) on C. sakazakii cells are scarcely known. Here, we explored the effect of ferric ions on the growth of planktonic C. sakazakii, biofilm formation, and swarming motility by crystal violet staining (CVS), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and swarming assay. Our study demonstrated that ferric ions facilitated the growth of planktonic C. sakazakii, while hemin at concentrations ranging from 50 to 800 μmol/L promoted biofilm formation and at concentrations between 50 and 200 μmol/L enhanced the swarming motility of C. sakazakii. Furthermore, high hemin concentrations (400-800 μmol/L) were found to reduce flagellar length, as confirmed by transmission electron microscopy (TEM). These findings indicated that ferric ions mediated the swarming motility of C. sakazakii by regulating flagellar assembly. Finally, transcriptomic analysis of C. sakazakii was performed at hemin concentrations of 0, 50, and 200 μmol/L, which revealed that several genes associated with iron transport and metabolism, and flagellar assembly were essential for the survival of C. sakazakii under hemin treatment. Our findings revealed the molecular basis of ferric ions on C. sakazakii growth and biofilm formation, thus providing a novel perspective for its prevention and control.}, } @article {pmid37855899, year = {2023}, author = {Gharajalar, SN and Tanhaee, S and Omidzadeh, M and Onsori, M}, title = {Detection of Antimicrobial Resistance and Biofilm Production Among Staphylococcus pseudintermedius from Canine Skin Lesions.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {}, number = {}, pages = {}, doi = {10.1089/mdr.2022.0257}, pmid = {37855899}, issn = {1931-8448}, abstract = {Aims: Staphylococcus pseudintermedius is an opportunistic pathogen also indicated as one of the major causes of skin infections in dogs. This study aimed to identify S. pseudintermedius isolated from canine skin lesions, evaluate their antibiotic resistance profile and biofilm production ability. Methodology: Lesions from 50 rural dogs with different skin lesions were sampled after pyoderma diagnosis by private practices. Bacterial species determination was investigated and susceptibility to nine antimicrobials were determined by means of Kirby-Bauer assay. Then seven antibiotic resistance genes, including mecA, blaZ, tetK, tetM, blaSHV, blaOXA-1, and blaTEM were screened by PCR. Moreover, biofilm formation ability of the strains was determined using the microtiter plate assay along with the presence of icaADBC genes. Results: A total of 37 (74%) isolates were identified as S. pseudintermedius. All S. pseudintermedius isolates were resistant to multiple drugs. Resistance to penicillin, amoxicillin-clavulanic acid, and cefazolin were higher than other antimicrobials. All the beta-lactam-resistant isolates carried blaZ, whereas mecA was found in 6 (16.21%) of them. Among tetracycline-resistant strains, the frequency of tetK and tetM determinants were 19 (90.47%) and 21 (100%), respectively. Finally, most cefazolin-resistant strains 31 (91.89%) were positive for blaTEM gene. The rate of biofilm production ability among S. pseudintermedius isolates was 35 (94.59%). Furthermore, the presence of icaA/D genes was detected in 35 (100%) and 29 (82.85%) of S. pseudintermedius strains, respectively. Conclusion: The high rates of antimicrobial resistance and biofilm production ability among S. pseudintermedius isolates, emphasize the urgent need to use more effective infection control policies and guidelines for antimicrobial use.}, } @article {pmid37855639, year = {2023}, author = {Holger, DJ and El Ghali, A and Bhutani, N and Lev, KL and Stamper, K and Kebriaei, R and Kunz Coyne, AJ and Morrisette, T and Shah, R and Alexander, J and Lehman, SM and Rojas, LJ and Marshall, SH and Bonomo, RA and Rybak, MJ}, title = {Phage-antibiotic combinations against multidrug-resistant Pseudomonas aeruginosa in in vitro static and dynamic biofilm models.}, journal = {Antimicrobial agents and chemotherapy}, volume = {}, number = {}, pages = {e0057823}, doi = {10.1128/aac.00578-23}, pmid = {37855639}, issn = {1098-6596}, abstract = {Biofilm-producing Pseudomonas aeruginosa infections pose a severe threat to public health and are responsible for high morbidity and mortality. Phage-antibiotic combinations (PACs) are a promising strategy for combatting multidrug-resistant (MDR), extensively drug-resistant (XDR), and difficult-to-treat P. aeruginosa infections. Ten MDR/XDR P. aeruginosa strains and five P. aeruginosa-specific phages were genetically characterized and evaluated based upon their antibiotic susceptibilities and phage sensitivities. Two selected strains, AR351 (XDR) and I0003-1 (MDR), were treated singly and in combination with either a broad-spectrum or narrow-spectrum phage, phage EM-T3762627-2_AH (EM), or 14207, respectively, and bactericidal antibiotics of five classes in biofilm time-kill analyses. Synergy and/or bactericidal activity was demonstrated with all PACs against one or both drug-resistant P. aeruginosa strains (average reduction: -Δ3.32 log10 CFU/cm[2]). Slightly improved ciprofloxacin susceptibility was observed in both strains after exposure to phages (EM and 14207) in combination with ciprofloxacin and colistin. Based on phage cocktail optimization with four phages (EM, 14207, E20050-C (EC), and 109), we identified several effective phage-antibiotic cocktails for further analysis in a 4-day pharmacokinetic/pharmacodynamic in vitro biofilm model. Three-phage cocktail, EM + EC + 109, in combination with ciprofloxacin demonstrated the greatest biofilm reduction against AR351 (-Δ4.70 log10 CFU/cm[2] from baseline). Of remarkable interest, the addition of phage 109 prevented phage resistance development to EM and EC in the biofilm model. PACs can demonstrate synergy and offer enhanced eradication of biofilm against drug-resistant P. aeruginosa while preventing the emergence of resistance.}, } @article {pmid37855449, year = {2023}, author = {Robertsson, C and Svensäter, G and Davies, JR and Bay Nord, A and Malmodin, D and Wickström, C}, title = {Synergistic metabolism of salivary MUC5B in oral commensal bacteria during early biofilm formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0270423}, doi = {10.1128/spectrum.02704-23}, pmid = {37855449}, issn = {2165-0497}, abstract = {Bacterial metabolism in oral biofilms is comprised of complex networks of nutritional chains and biochemical regulations. These processes involve both intraspecies and interspecies networks as well as interactions with components from host saliva, gingival crevicular fluid, and dietary intake. In a previous paper, a large salivary glycoprotein, mucin MUC5B, was suggested to promote a dental health-related phenotype in the oral type strain of Streptococcus gordonii DL1, by regulating bacterial adhesion and protein expression. In this study, nuclear magnetic resonance-based metabolomics was used to examine the effects on the metabolic output of monospecies compared to dual species early biofilms of two clinical strains of oral commensal bacteria, S. gordonii and Actinomyces naeslundii, in the presence of MUC5B. The presence of S. gordonii increased colonization of A. naeslundii on salivary MUC5B, and both commensals were able to utilize MUC5B as a sole nutrient source during early biofilm formation. The metabolomes suggested that the bacteria were able to release mucin carbohydrates from oligosaccharide side chains as well as amino acids from the protein core. Synergistic effects were also seen in the dual species biofilm metabolome compared to the monospecies, indicating that A. naeslundii and S. gordonii cooperated in the degradation of salivary MUC5B. A better understanding of bacterial interactions and salivary-mediated regulation of early dental biofilm activity is meaningful for understanding oral biofilm physiology and may contribute to the development of future prevention strategies for biofilm-induced oral disease.IMPORTANCEThe study of bacterial interactions and salivary-mediated regulation of early dental biofilm activity is of interest for understanding oral microbial adaptation to environmental cues and biofilm maturation. Findings in oral commensals can prove useful from the perspectives of both oral and systemic health of the host, as well as the understanding of general microbial biofilm physiology. The knowledge may provide a basis for the development of prognostic biomarkers, or development of new treatment strategies, related to oral health and disease and possibly also to other biofilm-induced conditions. The study is also an important step toward developing the methodology for similar studies in other species and/or growth conditions.}, } @article {pmid37854331, year = {2023}, author = {Leighton, RE and Xiong, L and Anderson, GK and Astarita, GM and Cai, G and Norman, RS and Decho, AW}, title = {Vibrio parahaemolyticus and Vibrio vulnificus in vitro biofilm dispersal from microplastics influenced by simulated human environment.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1236471}, pmid = {37854331}, issn = {1664-302X}, abstract = {Growing concerns exist regarding human ingestion of contaminated seafood that contains Vibrio biofilms on microplastics (MPs). One of the mechanisms enhancing biofilm related infections in humans is due to biofilm dispersion, a process that triggers release of bacteria from biofilms into the surrounding environment, such as the gastrointestinal tract of human hosts. Dispersal of cells from biofilms can occur in response to environmental conditions such as sudden changes in temperature, pH and nutrient conditions, as the bacteria leave the biofilm to find a more stable environment to colonize. This study evaluated how brief exposures to nutrient starvation, elevated temperature, different pH levels and simulated human media affect Vibrio parahaemolyticus and Vibrio vulnificus biofilm dispersal and processes on and from low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS) MPs. Both species were able to adequately disperse from all types of plastics under most exposure conditions. V. parahaemolyticus was able to tolerate and survive the low pH that resembles the gastric environment compared to V. vulnificus. pH had a significantly (p ≤ 0.05) positive effect on overall V. parahaemolyticus biofilm biomass in microplates and cell colonization from PP and PS. pH also had a positive effect on V. vulnificus cell colonization from LDPE and PP. However, most biofilm biomass, biofilm cell and dispersal cell densities of both species greatly varied after exposure to elevated temperature, pH, and nutrient starvation. It was also found that certain exposures to simulated human media affected both V. parahaemolyticus and V. vulnificus biofilm biomass and biofilm cell densities on LDPE, PP and PS compared to exposure to traditional media of similar pH. Cyclic-di-GMP was higher in biofilm cells compared to dispersal cells, but exposure to more stressful conditions significantly increased signal concentrations in both biofilm and dispersal states. Taken together, this study suggests that human pathogenic strains of V. parahaemolyticus and V. vulnificus can rapidly disperse with high cell densities from different plastic types in vitro. However, the biofilm dispersal process is highly variable, species specific and dependent on plastic type, especially under different human body related environmental exposures.}, } @article {pmid37853796, year = {2023}, author = {Zhang, J and Zhao, S and Zhang, S and Zhu, H and Zhang, Y and Li, L and Liu, C and Shi, J}, title = {A nanozyme-reinforced injectable photodynamic hydrogel for combating biofilm infection.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb01688a}, pmid = {37853796}, issn = {2050-7518}, abstract = {Bacterial biofilm-associated infectious diseases remain serious menaces to human health. Recently, photodynamic therapy (PDT) has become a prospective strategy for combating biofilm infection. However, anaerobic conditions in a biofilm greatly inhibit its therapeutic efficacy. Here, a nanozyme-reinforced injectable hydrogel is prepared using Ca[2+]-crosslinked sodium alginate incorporated with photosensitizer-loaded MnO2 nanosheets and CaO2 nanoparticles for O2 self-sufficient PDT to eradicate biofilm infection. In our design, CaO2 reacts with water to produce locally concentrated H2O2, which could be catalyzed by MnO2 nanosheets (catalase-mimic nanozymes) to generate O2 and greatly relieve the hypoxic conditions in the biofilm, thus significantly strengthening PDT efficacy. In vitro assays confirmed that the hybrid hydrogel not only exhibits high-performance bactericidal activity in combating both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli but also shows great efficacy in eliminating biofilm infection. Moreover, benefiting from its good syringeability, the hybrid hydrogel is prone to fit irregular wounds and exhibits high efficiency in promoting wound healing in a biofilm-infected mice model. Besides, no obvious toxicity is detected in the hybrid hydrogel. Overall, we envision that our designed hydrogel could provide a prospective solution for combating biofilm-associated infections.}, } @article {pmid37853689, year = {2023}, author = {Jayaraman, S and Adhilaxmi Kannan, M and Rajendhran, N and John, GJ and Ramasamy, T}, title = {Indole-3-acetic acid impacts biofilm formation and virulence production of Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-16}, doi = {10.1080/08927014.2023.2269537}, pmid = {37853689}, issn = {1029-2454}, abstract = {Bacterial pathogenesis involves complex mechanisms contributing to virulence and persistence of infections. Understanding the multifactorial nature of bacterial infections is crucial for developing effective interventions. The present study investigated the efficacy of indole-3-acetic acid (IAA) against Pseudomonas aeruginosa with various end points including antibacterial activity, minimum inhibitory concentration (MIC), virulence factor production, biofilm inhibition, bacterial cell detachment, and viability assays. Results showed significant biofilm inhibition, bacterial cell detachment, and modest effects on bacterial viability. Microscopic analysis confirmed the disintegrated biofilm matrix, supporting the inhibitory effect of IAA. Additionally, molecular docking studies revealed potential mechanisms of action through active bond interactions between IAA and virulence proteins. These findings highlight IAA as an effective antibiofilm agent against P. aeruginosa.}, } @article {pmid37853059, year = {2023}, author = {Guan, X and Jin, L and Zhou, H and Chen, J and Wan, H and Bao, Y and Yang, J and Yu, D and Wan, H}, title = {Polydatin prevent lung epithelial cell from Carbapenem-resistant Klebsiella pneumoniae injury by inhibiting biofilm formation and oxidative stress.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {17736}, pmid = {37853059}, issn = {2045-2322}, support = {2023ZF157//Liang Jin/ ; grant number 81930111//Haitong Wan/ ; }, abstract = {Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes severe inflammation in various infectious diseases, such as bloodstream infections, respiratory and urinary tract infections, which leads to high mortality. Polydatin (PD), an active ingredient of Yinhuapinggan granule, has attracted worldwide attention for its powerful antioxidant, anti-inflammatory, antitumor, and antibacterial capacity. However, very little is known about the effect of PD on CRKP. In this research, we evaluated the inhibitory effects of PD on both the bacterial level and the bacterial-cell co-culture level on anti-biofilm and efflux pumps and the other was the inhibitory effect on apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) after CRKP induction. Additionally, we validated the mechanism of action by qRT-PCR and western blot in human lung epithelial cells. Firstly, PD was observed to have an inhibitory effect on the biofilm of CRKP and the efflux pump AcrAB-TolC. Mechanically, CRKP not only inhibited the activation of Nuclear Factor erythroid 2-Related Factor 2 (Nrf-2) but also increased the level of ROS in cells. These results showed that PD could inhibit ROS and activate Nrf-2 production. Together, our research demonstrated that PD inhibited bacterial biofilm formation and efflux pump AcrAB-TolC expression and inhibited CRKP-induced cell damage by regulating ROS and Nrf-2-regulated antioxidant pathways.}, } @article {pmid37852119, year = {2023}, author = {Naman, A and Tahseen, H and Nawaz, H and Majeed, MI and Ali, A and Haque, A and Akbar, MU and Mehmood, N and Nosheen, R and Nadeem, S and Shahzadi, A and Imran, M}, title = {Surface-enhanced Raman spectroscopy for characterization of supernatant samples of biofilm forming bacterial strains.}, journal = {Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy}, volume = {305}, number = {}, pages = {123414}, doi = {10.1016/j.saa.2023.123414}, pmid = {37852119}, issn = {1873-3557}, abstract = {Staphylococcus epidermidis is considered major cause of nosocomial infections. Its pathogenicity is mainly due to the ability to form biofilms on different surfaces, particularly indwelling medical devices. This bacterium consists of different strains consisting of non, medium and strong biofilm forming ones. Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique that can be used to detect and analyze biochemical composition of the supernatant samples of different strains of bacteria including non, medium and strong biofilm forming bacterial strains. SERS is a powerful technique for the robust, reliable, rapid detection and discrimination of bacteria in the form of characteristic SERS spectral features which can be used for detection and classification. SERS is used to differentiate three classes of bacteria with respect to their biofilm forming ability. Silver nanoparticles (Ag NPs) are used as SERS substrate and synthesized with chemical reduction method. Principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) are used to discriminate SERS spectral data sets of non, medium and strong biofilm forming bacteria. PLS-DA analysis is a multivariate statistical technique that can be used to analyze data from bacterial sets.}, } @article {pmid37851325, year = {2023}, author = {Rahmani, A and Parizadeh, L and Baud, M and Francois, Y and Bazire, A and Rodrigues, S and Fleury, Y and Cuny, H and Debosse, E and Cabon, J and Louboutin, L and Bellec, L and Danion, M and Morin, T}, title = {Potential of Marine Strains of Pseudoalteromonas to Improve Resistance of Juvenile Sea Bass to Pathogens and Limit Biofilm Development.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {37851325}, issn = {1867-1314}, support = {PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; PFEA470019FA1000012//European Maritime and Fisheries Fund/ ; }, abstract = {The European sea bass (Dicentrarchus labrax), one of the most produced marine fish species in Europe, is acutely vulnerable to multiple infectious hazards. In this study, we investigated the potential probiotic effect of some marine Pseudoalteromonas bacterial strains against two major pathogens of this species, Vibrio harveyi and the nervous necrosis virus (NNV), and examined their antibiofilm effect. Impregnation phase was done by repeated immersion of juvenile's sea bass during 8 to 12 weeks in seawater containing the probiotic candidates at a concentration of 10[6] CFU/mL. Four candidates were tested: (1) a combination of two strains producing antimicrobial compounds, hCg-42 and hOe-125; (2) strain 3J6, with known antibiofilm properties; (3) strain RA15, from the same genus, but with no identified probiotic effect; and (4) a control group without probiotics. At the end of the impregnation phase, fish underwent an infection challenge with V. harveyi or with a pathogenic strain of NNV and mortality was monitored. For the V. harveyi challenge, improved survival rates of 10 and 25% were obtained for the RA15 and the mix hCg-42 + hOe-125-impregnated groups, respectively. For the NNV challenge, no significant benefic effect of the probiotics on infection kinetics or cumulative mortality was observed. At the end of the impregnation phase, the maximal thickness of biofilm was significantly lower in the 3J6, double strain, and RA15 groups, compared with the non-impregnated control group. This study highlights the interesting probiotic potential of marine bacteria to limit mortalities induced by bacterial pathogens as well as biofilm development.}, } @article {pmid37850975, year = {2023}, author = {Monteith, W and Pascoe, B and Mourkas, E and Clark, J and Hakim, M and Hitchings, MD and McCarthy, N and Yahara, K and Asakura, H and Sheppard, SK}, title = {Contrasting genes conferring short- and long-term biofilm adaptation in Listeria.}, journal = {Microbial genomics}, volume = {9}, number = {10}, pages = {}, doi = {10.1099/mgen.0.001114}, pmid = {37850975}, issn = {2057-5858}, abstract = {Listeria monocytogenes is an opportunistic food-borne bacterium that is capable of infecting humans with high rates of hospitalization and mortality. Natural populations are genotypically and phenotypically variable, with some lineages being responsible for most human infections. The success of L. monocytogenes is linked to its capacity to persist on food and in the environment. Biofilms are an important feature that allow these bacteria to persist and infect humans, so understanding the genetic basis of biofilm formation is key to understanding transmission. We sought to investigate the biofilm-forming ability of L. monocytogenes by identifying genetic variation that underlies biofilm formation in natural populations using genome-wide association studies (GWAS). Changes in gene expression of specific strains during biofilm formation were then investigated using RNA sequencing (RNA-seq). Genetic variation associated with enhanced biofilm formation was identified in 273 genes by GWAS and differential expression in 220 genes by RNA-seq. Statistical analyses show that the number of overlapping genes flagged by either type of experiment is less than expected by random sampling. This novel finding is consistent with an evolutionary scenario where rapid adaptation is driven by variation in gene expression of pioneer genes, and this is followed by slower adaptation driven by nucleotide changes within the core genome.}, } @article {pmid37849666, year = {2023}, author = {Rotello, VM}, title = {Nanomaterials for Fighting Multidrug-Resistant Biofilm Infections.}, journal = {BME frontiers}, volume = {4}, number = {}, pages = {0017}, pmid = {37849666}, issn = {2765-8031}, abstract = {Multidrug-resistant bacterial infections represent a dire threat to global health. The development of antibiotic resistance in bacteria coupled with the lack of development of new antibiotics is creating infections requiring antibiotics of last resort, and even some infections for which we have no available treatment. Biofilm-based infections present some of the most challenging targets for treatment. The biofilm matrix provides a physical barrier that can impede access of antibiotics and antimicrobials to resident bacteria. The phenotypic diversity found in biofilms further exacerbates the difficulty of eliminating infections, with quiescent "persister" cells evading therapeutics and re-initiating infections after treatment. Nanomaterials provide a tool for combatting these refractory biofilm infections. The distinctive size regime and physical properties of nanomaterials provide them with the capability to penetrate and disrupt biofilms. Nanomaterials can also access antimicrobial pathways inaccessible to conventional antimicrobials, providing a synergistic strategy for treating biofilm infections. This review will summarize key challenges presented by antibiotic resistance and biofilms when treating infection and provide selected examples of how nanomaterials are being used to address these challenges.}, } @article {pmid37848997, year = {2023}, author = {Zhang, Z and Liu, Y and Zhao, W and Ji, M}, title = {Radiation impacts gene redundancy and biofilm regulation of cryoconite microbiomes in Northern Hemisphere glaciers.}, journal = {Microbiome}, volume = {11}, number = {1}, pages = {228}, pmid = {37848997}, issn = {2049-2618}, abstract = {BACKGROUND: Glaciers harbor diverse microorganisms adapted to extreme conditions with high radiation, fluctuating temperature, and low nutrient availability. In glacial ecosystems, cryoconite granules are hotspots of microbial metabolic activity and could influences the biogeochemical cycle on glacier surface. Climate change could influence glacier dynamics by changing regional meteorological factors (e.g., radiation, precipitation, temperature, wind, and evaporation). Moreover, meteorological factors not only influence glacier dynamics but also directly or indirectly influence cryoconite microbiomes. However, the relationship of the meteorological factors and cryoconite microbiome are poorly understood.

RESULTS: Here, we collected 88 metagenomes from 26 glaciers distributed in the Northern Hemisphere with corresponding public meteorological data to reveal the relationship between meteorological factors and variation of cryoconite microbiome. Our results showed significant differences in taxonomic and genomic characteristics between cryoconite generalists and specialists. Additionally, we found that the biogeography of both generalists and specialists was influenced by solar radiation. Specialists with smaller genome size and lower gene redundancy were more abundant under high radiation stress, implying that streamlined genomes are more adapted to high radiation conditions. Network analysis revealed that biofilm regulation is a ubiquitous function in response to radiation stress, and hub genes were associated with the formation and dispersion of biofilms.

CONCLUSION: These findings enhance our understanding of glacier cryoconite microbiome variation on a hemispheric scale and indicate the response mechanisms to radiation stress, which will support forecasts of the ecological consequences of future climate change. Video Abstract.}, } @article {pmid37847735, year = {2023}, author = {Evans, CR and Smiley, MK and Asahara Thio, S and Wei, M and Florek, LC and Dayton, H and Price-Whelan, A and Min, W and Dietrich, LEP}, title = {Spatial heterogeneity in biofilm metabolism elicited by local control of phenazine methylation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {43}, pages = {e2313208120}, doi = {10.1073/pnas.2313208120}, pmid = {37847735}, issn = {1091-6490}, support = {R01AI103369//HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; R01EB029523//HHS | NIH | National Institute of Biomedical Imaging and Bioengineering (NIBIB)/ ; }, abstract = {Within biofilms, gradients of electron acceptors such as oxygen stimulate the formation of physiological subpopulations. This heterogeneity can enable cross-feeding and promote drug resilience, features of the multicellular lifestyle that make biofilm-based infections difficult to treat. The pathogenic bacterium Pseudomonas aeruginosa produces pigments called phenazines that can support metabolic activity in hypoxic/anoxic biofilm subzones, but these compounds also include methylated derivatives that are toxic to their producer under some conditions. In this study, we uncover roles for the global regulators RpoS and Hfq/Crc in controlling the beneficial and detrimental effects of methylated phenazines in biofilms. Our results indicate that RpoS controls phenazine methylation by modulating activity of the carbon catabolite repression pathway, in which the Hfq/Crc complex inhibits translation of the phenazine methyltransferase PhzM. We find that RpoS indirectly inhibits expression of CrcZ, a small RNA that binds to and sequesters Hfq/Crc, specifically in the oxic subzone of P. aeruginosa biofilms. Deletion of rpoS or crc therefore leads to overproduction of methylated phenazines, which we show leads to increased metabolic activity-an apparent beneficial effect-in hypoxic/anoxic subpopulations within biofilms. However, we also find that under specific conditions, biofilms lacking RpoS and/or Crc show increased sensitivity to phenazines indicating that the increased metabolic activity in these mutants comes at a cost. Together, these results suggest that complex regulation of PhzM allows P. aeruginosa to simultaneously exploit the benefits and limit the toxic effects of methylated phenazines.}, } @article {pmid37847552, year = {2023}, author = {Kovacs, CJ and Rapp, EM and McKenzie, SM and Mazur, MZ and Mchale, RP and Brasko, B and Min, MY and Burpo, FJ and Barnhill, JC}, title = {Disruption of Biofilm by Bacteriophages in Clinically Relevant Settings.}, journal = {Military medicine}, volume = {}, number = {}, pages = {}, doi = {10.1093/milmed/usad385}, pmid = {37847552}, issn = {1930-613X}, abstract = {INTRODUCTION: Antibiotic-resistant bacteria are a growing threat to civilian and military health today. Although infections were once easily treatable by antibiotics and wound cleaning, the frequent mutation of bacteria has created strains impermeable to antibiotics and physical attack. Bacteria further their pathogenicity because of their ability to form biofilms on wounds, medical devices, and implant surfaces. Methods for treating biofilms in clinical settings are limited, and when formed by antibiotic-resistant bacteria, can generate chronic infections that are recalcitrant to available therapies. Bacteriophages are natural viral predators of bacteria, and their ability to rapidly destroy their host has led to increased attention in potential phage therapy applications.

MATERIALS AND METHODS: The present article sought to address a knowledge gap in the available literature pertaining to the usage of bacteriophage in clinically relevant settings and the resolution of infections particular to military concerns. PRISMA guidelines were followed for a systematic review of available literature that met the criteria for analysis and inclusion. The research completed for this review article originated from the U.S. Military Academy's library "Scout" search engine, which complies results from 254 available databases (including PubMed, Google Scholar, and SciFinder). The search criteria included original studies that employed bacteriophage use against biofilms, as well as successful phage therapy strategies for combating chronic bacterial infections. We specifically explored the use of bacteriophage against antibiotic- and treatment-resistant bacteria.

RESULTS: A total of 80 studies were identified that met the inclusion criteria following PRISMA guidelines. The application of bacteriophage has been demonstrated to robustly disrupt biofilm growth in wounds and on implant surfaces. When traditional therapies have failed to disrupt biofilms and chronic infections, a combination of these treatments with phage has proven to be effective, often leading to complete wound healing without reinfection.

CONCLUSIONS: This review article examines the available literature where bacteriophages have been utilized to treat biofilms in clinically relevant settings. Specific attention is paid to biofilms on implant medical devices, biofilms formed on wounds, and clinical outcomes, where phage treatment has been efficacious. In addition to the clinical benefit of phage therapies, the military relevance and treatment of combat-related infections is also examined. Phages offer the ability to expand available treatment options in austere environments with relatively low cost and effort, allowing the impacted warfighter to return to duty quicker and healthier.}, } @article {pmid37844959, year = {2023}, author = {Huang, YH and Lee, YH and Lin, CJ and Hsu, LH and Chen, YL}, title = {Deubiquitination module is critical for oxidative stress response and biofilm formation in Candida glabrata.}, journal = {Medical mycology}, volume = {}, number = {}, pages = {}, doi = {10.1093/mmy/myad099}, pmid = {37844959}, issn = {1460-2709}, abstract = {Candidiasis is one of the most important fungal diseases and generally refers to diseases of the skin or mucosal tissues caused by Candida species. Candida glabrata is an opportunistic human fungal pathogen. Infection with C. glabrata has significantly increased due to innate antifungal drug tolerance and the ability to adhere to mucocutaneous surfaces. SAGA complex contains two different post-translational modifications, histone acetylation (HAT module) and deubiquitination (DUB module), which are decisive in gene regulation and highly conserved in eukaryotes. Previous research in our laboratory found that the HAT module ADA2 could regulate C. glabrata oxidative stress tolerance, drug tolerance, cell wall integrity, and virulence. However, the roles of the DUB module that is comprised of UBP8, SGF11, SGF73, and SUS1 genes in those phenotypes are not yet understood. In this study, we found that DUB module genes UBP8, SGF11, and SUS1, but not SGF73 positively regulate histone H2B deubiquitination. Furthermore, ubp8, sgf11, and sus1 mutants exhibited decreased biofilm formation and sensitivity to cell wall-perturbing agent sodium dodecyl sulfate and antifungal drug amphotericin B. In addition, sgf73 mutant showed increased biofilm formation but was susceptible to oxidative stresses, antifungal drugs, and cell wall perturbing agents. The ubp8, sgf11, and sus1 mutants showed marginal hypovirulence, while the sgf73 mutant exhibited virulence similar to the wild type in a murine systemic infection model. In conclusion, the C. glabrata DUB module plays distinct roles in H2B ubiquitination, oxidative stress response, biofilm formation, cell wall integrity and drug tolerance, but exhibits minor roles in virulence.}, } @article {pmid37844801, year = {2023}, author = {Pajavand, H and Mobarez, AM and Barati, A and Nikkhah, M and Delnavazi, MR and Abiri, R and Alvandi, AH and Karimiravesh, R}, title = {Evaluation of combined Carbon dots and Ciprofloxacin on the expression level of pslA, pelA, and ppyR genes and biofilm production in Ciprofloxacin-resistant P. aeruginosa isolates from burn wound infection in Iran.}, journal = {Journal of global antimicrobial resistance}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jgar.2023.10.005}, pmid = {37844801}, issn = {2213-7173}, abstract = {OBJECTIVES: Antimicrobial resistance and biofilm formation are increasingly significant public health concerns. This study aimed to examine the antibacterial and anti-biofilm properties of C-dots alone and in combination with antibiotics against biofilm-forming isolates of P. aeruginosa.

METHODS: The antibacterial property of C- dots was investigated by broth micro-dilution method against ATCC PAO1 and P. aeruginosa clinical isolates. The antibacterial effect of the C-dot and ciprofloxacin combination was investigated using the checkerboard method. The anti-biofilm effect of the C-dot alone and its combination with ciprofloxacin was evaluated using the microtiter plate method. Subsequently, the toxicity of each agent was tested on L929 fibroblast cells. In the end, the effects of C-dot on the expression levels of pslA, pelA, and ppyR genes were determined using real-time quantitative PCR.

RESULTS: The combination of C-dot and ciprofloxacin exhibited a synergistic effect. Additionally, this compound substantially decreased bacterial growth (P<0.0001) and inhibited biofilm formation at MIC (96 μg/ml) and sub-MIC (48 μg/ml) concentration (P<0.0053, P<0.01). After being exposed to C-dot at a concentration of 1mg/ml for 24 hours, the survival rate of L929 cells was 87.3%. The expression of genes pslA, pelA and ppyR, associated with biofilm formation in P. aeruginosa, was significantly reduced upon exposure to C-dot (P<0.0023).

CONCLUSION: The findings demonstrate a promising new treatment method for infections. Furthermore, reducing the dosage of antibiotics can lead to an improvement in the toxic effects caused by dose-dependent antibiotics and antimicrobial activity.}, } @article {pmid37844474, year = {2023}, author = {Sharma, C and Verma, M and Abidi, SMS and Shukla, AK and Acharya, A}, title = {Functional fluorescent nanomaterials for the detection, diagnosis and control of bacterial infection and biofilm formation: Insight towards mechanistic aspects and advanced applications.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {232}, number = {}, pages = {113583}, doi = {10.1016/j.colsurfb.2023.113583}, pmid = {37844474}, issn = {1873-4367}, abstract = {Infectious diseases resulting from the high pathogenic potential of several bacteria possesses a major threat to human health and safety. Traditional methods used for screening of these microorganisms face major issues with respect to detection time, selectivity and specificity which may delay treatment for critically ill patients past the optimal time. Thus, a convincing and essential need exists to upgrade the existing methodologies for the fast detection of bacteria. In this context, increasing number of newly emerging nanomaterials (NMs) have been discovered for their effective use and applications in the area of diagnosis in bacterial infections. Recently, functional fluorescent nanomaterials (FNMs) are extensively explored in the field of biomedical research, particularly in developing new diagnostic tools, nanosensors, specific imaging modalities and targeted drug delivery systems for bacterial infection. It is interesting to note that organic fluorophores and fluorescent proteins have played vital role for imaging and sensing technologies for long, however, off lately fluorescent nanomaterials are increasingly replacing these due to the latter's unprecedented fluorescence brightness, stability in the biological environment, high quantum yield along with high sensitivity due to enhanced surface property etc. Again, taking advantage of their photo-excitation property, these can also be used for either photothermal and photodynamic therapy to eradicate bacterial infection and biofilm formation. Here, in this review, we have paid particular attention on summarizing literature reports on FNMs which includes studies detailing fluorescence-based bacterial detection methodologies, antibacterial and antibiofilm applications of the same. It is expected that the present review will attract the attention of the researchers working in this field to develop new engineered FNMs for the comprehensive diagnosis and treatment of bacterial infection and biofilm formation.}, } @article {pmid37844038, year = {2023}, author = {Shakib, P and Saki, R and Zolfaghari, MR and Goudarzi, G}, title = {Efflux Pump and Biofilm Inhibitory Activity of Nanoparticles in Acinetobacter Baumannii: a Systematic Review.}, journal = {Clinical laboratory}, volume = {69}, number = {10}, pages = {}, doi = {10.7754/Clin.Lab.2023.230227}, pmid = {37844038}, issn = {1433-6510}, abstract = {BACKGROUND: Acinetobacter baumannii produce biofilm and efflux pumps. This systematic review study aimed to provide new strategies to inhibit the efflux pumps and biofilm in A. baumannii using nanoparticles.

METHODS: In this research, analyses from 2000 to February 24, 2022, were performed by the Statement of Preferred Reporting Items for Systematic Reviews (PRISMA). Keywords include Acinetobacter baumannii (A. baumannii) AND (biofilm) AND (anti-biofilm activity) AND (nanoparticles) AND (solid lipid NPS) AND (lipid nanocarriers), and in other searches include Acinetobacter baumannii (A. baumanni) AND (efflux pumps) AND (nanoparticles) AND (solid lipid NPS) AND (lipid nanocarriers). Searches were conducted in English databases, including Science Direct, PubMed, Scopus, Ovid, and Cochrane.

RESULTS: At first, 136 studies were extracted, but after removing duplicates, 116 cases remained for further analysis. After evaluating the title and abstract of each study, 95 unrelated studies were excluded. The remaining 25 studies were reviewed based on full texts. Considering the inclusion/exclusion criteria, 19 studies were selected. In this study, metal nanoparticles were the most used nanoparticles for anti-biofilm and efflux pump purposes, and among these nanoparticles, silver nanoparticles (AgNPs) contributed the most.

CONCLUSIONS: The present study shows that nanoparticles have potential and significant effects in inhibiting biofilm and efflux pumps in A. baumannii isolates, which researchers can consider in light of the increasing prevalence of antibiotic resistance.}, } @article {pmid37842394, year = {2023}, author = {Arumuganainar, D and Subramaniam, G and Kurumathur Vasudevan, A and Subbusamy Kanakasabapathy, B}, title = {An In Vitro Evaluation of the Antibacterial Efficacy of Solanum xanthocarpum Extracts on Bacteria From Dental Plaque Biofilm.}, journal = {Cureus}, volume = {15}, number = {9}, pages = {e45202}, pmid = {37842394}, issn = {2168-8184}, abstract = {OBJECTIVE: The focus of research has recently shifted toward developing herbal-based medicines due to the emerging bacterial resistance and side effects of antibiotics. Solanum xanthocarpum (Sx) is a medicinal plant with potent pharmacological properties. This study aimed to evaluate the antibacterial activity of its crude extracts on bacteria isolated from dental plaque in patients with gingivitis.

MATERIALS AND METHODS: Aqueous, ethyl acetate, hexane, chloroform, and ethanolic extracts were prepared from Sx. Dental plaque samples were collected from patients with plaque-induced gingivitis. Disk diffusion assay was performed to determine the antibacterial activity of the extracts at concentrations of 25 mg/ml, 50 mg/ml, and 75 mg/ml with ampicillin 200 mg/ml as a positive control. The minimum inhibitory concentration (MIC) of the aqueous extract was also evaluated by broth dilution test against bacteria isolated from dental plaque biofilm.

RESULTS: The antibacterial activity was estimated by measuring the zones of inhibition through the disc diffusion method. The Kruskal Wallis with Dunn post hoc test performed for intergroup comparison between the various extracts showed a statistically significant difference in inhibition of bacterial growth between 25 mg/ml and 75 mg/ml concentrations. There was no significant difference between the 75 mg/ml Sx concentration and the positive control. In addition, the MIC was elucidated to be 0.625 g/ml, at which there was maximum inhibition of bacterial growth.

CONCLUSION: The Sx extract exhibited antibacterial activity against periodontal pathogens. Thus, it can be concluded that optimum concentrations of Sx could be used in therapeutic strategies to prevent and manage periodontal diseases.}, } @article {pmid37841170, year = {2023}, author = {Rhoomi, ZR and Ahmed, DS and Jabir, MS and Balasubramanian, B and Al-Garadi, MA and Swelum, AA}, title = {Facile Hydrothermal Synthesis of BiVO4/MWCNTs Nanocomposites and Their Influences on the Biofilm Formation of Multidrug Resistance Streptococcus mutans and Proteus mirabilis.}, journal = {ACS omega}, volume = {8}, number = {40}, pages = {37147-37161}, pmid = {37841170}, issn = {2470-1343}, abstract = {This study utilized a simple hydrothermal technique to prepare pure BiVO4 and tightly bound BiVO4/multiwalled carbon nanotubes (MWCNTs) nanocomposite materials. The surfactant was employed to control the growth, size, and assembly of BiVO4 and the nanocomposite. Various techniques including X-ray diffraction (XRD), Ultraviolet-visible (UV-vis), photoluminescence (PL), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were utilized to analyze and characterize BiVO4 and the BiVO4/MWCNTs nanocomposite. Through XRD analysis, it was found that the carbon nanotubes were effectively embedded within the lattice of BiVO4 without generating any separate impurity phase and had no influence on the BiVO4 monoclinic structure. TEM images confirmed the presence of MWCNTs within BiVO4. Furthermore, adding MWCNTs in the BiVO4/MWCNTs nanocomposite resulted in an effective charge transfer transition and improved carrier separation, as evidenced by PL analysis. The introduction of MWCNTs also led to a significant reduction in the optical band gap due to quantum effects. Finally, the antibacterial activity of pure BiVO4 and the BiVO4/MWCNTs nanocomposite was assessed by exposing Proteus mirabilis and Streptococcus mutans to these materials. Biofilm inhibition and antibiofilm activity were measured using a crystal violet assay and a FilmTracer LIVE/DEAD Biofilm Viability Kit. The results demonstrated that pure BiVO4 and BiVO4/MWCNTs effectively inhibited biofilm formation. In conclusion, both pure BiVO4 and BiVO4/MWCNTs are promising materials for inhibiting the bacterial biofilm during bacterial infections.}, } @article {pmid37839208, year = {2023}, author = {Cruces, M and Suárez, J and Nancucheo, I and Schwarz, A}, title = {Optimization of the chemolithotrophic denitrification of ion exchange concentrate using hydrogen-based membrane biofilm reactors.}, journal = {Journal of environmental management}, volume = {348}, number = {}, pages = {119283}, doi = {10.1016/j.jenvman.2023.119283}, pmid = {37839208}, issn = {1095-8630}, abstract = {A H2-based membrane biofilm reactor (MBfR) was used to remove nitrate from a synthetic ion-exchange brine made up of 23.8 g L[-1] NaCl. To aid the selection of the best nitrate management strategy, our research was based on the integrated analysis of ionic exchange and MBfR processes, including a detailed cost analysis. The nitrate removal flux was not affected if key nutrients were present in the feed solution including potassium and sodium bicarbonate. Operating pH was maintained between 7 and 8. By using a H2 pressure of 15 psi, a hydraulic retention time (HRT) of 4 h, and a surface loading rate of 13.6 ± 0.2 g N m[-2] d[-1], the average nitrate removal flux was 3.3 ± 0.6 g N m[-2] d[-1]. At HRTs of up to 24 h, the system was able to maintain a removal flux of 1.6 ± 0.2 g N m[-2] d[-1]. Microbial diversity analysis showed that the consortium was dominated by the genera Sulfurimonas and Marinobacter. The estimated cost for a 200 m[3]/h capacity, coupled ion exchange (IX) + MBfR treatment plant is 0.43 USD/m[3]. This is a sustainable and competitive alternative to an IX-only plant for the same flowrate. The proposed treatment option allows for brine recycling and reduces costs by 55% by avoiding brine disposal expenses.}, } @article {pmid37839187, year = {2023}, author = {Cao, Y and Huang, R and Li, T and Pan, D and Shao, S and Wu, X}, title = {Effect of antibiotics on the performance of moving bed biofilm reactor for simultaneous removal of nitrogen, phosphorus and copper(II) from aquaculture wastewater.}, journal = {Ecotoxicology and environmental safety}, volume = {266}, number = {}, pages = {115590}, doi = {10.1016/j.ecoenv.2023.115590}, pmid = {37839187}, issn = {1090-2414}, abstract = {Co-existence of NO3[-]-N, antibiotics, phosphorus (P), and Cu[2+] in aquaculture wastewater has been frequently detected, but simultaneous removal and relationship between enzyme and pollutants removal are far from satisfactory. In this study, simultaneous removal of NO3[-]-N, P, antibiotics, and Cu[2+] by moving bed biofilm reactor (MBBR) was established. About 95.51 ± 3.40% of NO3[-]-N, 61.24 ± 3.51% of COD, 18.74 ± 1.05% of TP, 88% of Cu[2+] were removed synchronously in stage I, and antibiotics removal in stages I-IV was 73.00 ± 1.32%, 79.53 ± 0.88%, 51.07 ± 3.99%, and 33.59 ± 2.73% for tetracycline (TEC), oxytetracycline (OTC), chlortetracycline hydrochloride (CTC), sulfamethoxazole (SMX), respectively. The removal kinetics and toxicity of MBBR effluent were examined, indicating that the first order kinetic model could better reflect the removal of NO3[-]-N, TN, and antibiotics. Co-existence of multiple antibiotics and Cu[2+] was the most toxicity to E. coli growth. Key enzyme activity, reactive oxygen species (ROS) level, and its relationship with TN removal were investigated. The results showed that enzymes activities were significantly different under the co-existence of antibiotics and Cu[2+]. Meanwhile, different components of biofilm were extracted and separated, and enzymatic and non-enzymatic effects of biofilm were evaluated. The results showed that 70.00%- 94.73% of Cu[2+] was removed by extracellular enzyme in stages I-V, and Cu[2+] removal was mainly due to the action of extracellular enzyme. Additionally, microbial community of biofilm was assessed, showing that Proteobacteria, Bacteroidetes, and Gemmatimonadetes played an important role in the removal of NO3[-]-N, Cu[2+], and antibiotics at the phylum level. Finally, chemical bonds of attached and detached biofilm were characterized by X-ray photoelectron spectroscopy (XPS), and effect of nitrogen (N) and P was proposed under the co-existence of antibiotics and Cu[2+]. This study provides a theoretical basis for further exploring the bioremediation of NO3[-]-N, Cu[2+], and antibiotics in aquaculture wastewater.}, } @article {pmid37838674, year = {2023}, author = {Chen, Q and Ye, J and Li, XB and Zeng, K and Zeng, S}, title = {Drug resistance and influencing factors of biofilm bacteria in upper urinary calculi patients with double J stent indwelling.}, journal = {BMC urology}, volume = {23}, number = {1}, pages = {165}, pmid = {37838674}, issn = {1471-2490}, abstract = {OBJECTIVE: To analyze the distribution and drug resistance of biofilm bacteria infected with upper urinary calculi patients with double J stent indwelling, and to explore the influencing factors of Biofilm Bacteria Infections.

METHODS: A total of 400 patients with upper urinary calculi who adopted double J stent inserting in our hospital from January 2019 to January 2022 were included. Urine and double J stent samples were collected, pathogen cultures were performed, and then drug sensitivity test analysis was carried out for isolates. Univariate and multivariate logistic regression analyzes were used to analyze the influencing factors of patients with double J stent associated biofilm bacteria infections.

RESULTS: A total of 13 strains (3.2%) of biofilm bacteria were detected in urine samples and 168 strains (42%) in double J stent samples (P < 0.05), 95 strains (23.7%) of pathogenic bacteria were separated from urine samples and 117 strains (29.2%) from double J-stent samples (P > 0.05). Escherichia coli were the most common bacteria. There was significantly higher drug resistance observed in biofilm bacteria versus urine-cultured pathogens (P < 0.05). Advanced age, long-term catheterization, inadequate water intake, hypoproteinemia, abnormal renal function, and diabetes mellitus were independent risk factors for biofilm bacteria infection associated with double J stent(P < 0.05).

CONCLUSION: Among the upper urinary calculi patients with double J stent indwelling, the positive rate and drug resistance of biofilm bacteria obtained from double J stent were significantly higher than that from urine. More attention should be paid to the factors that influence biofilm bacteria infections.}, } @article {pmid37838636, year = {2023}, author = {Zhang, Y and Zhang, T and Qiu, Y and Zhang, M and Lu, X and Yang, W and Hu, L and Zhou, D and Gao, B and Lu, R}, title = {Transcriptomic Profiles of Vibrio parahaemolyticus During Biofilm Formation.}, journal = {Current microbiology}, volume = {80}, number = {12}, pages = {371}, pmid = {37838636}, issn = {1432-0991}, support = {JC2021027//Natural Science Research Project of Nantong Science and Technology Bureau/ ; 82072239//National Natural Science Foundation of China/ ; }, abstract = {Vibrio parahaemolyticus, the leading cause of bacterial seafood-associated gastroenteritis, can form biofilms. In this work, the gene expression profiles of V. parahaemolyticus during biofilm formation were investigated by transcriptome sequencing. A total of 183, 503, and 729 genes were significantly differentially expressed in the bacterial cells at 12, 24 and 48 h, respectively, compared with that at 6 h. Of these, 92 genes were consistently activated or repressed from 6 to 48 h. The genes involved in polar flagellum, chemotaxis, mannose-sensitive haemagglutinin type IV pili, capsular polysaccharide, type III secretion system 1 (T3SS1), T3SS2, thermostable direct hemolysin (TDH), type VI secretion system 1 (T6SS1) and T6SS2 were downregulated, whereas those involved in V. parahaemolyticus pathogenicity island (Vp-PAI) (except for T3SS2 and TDH) and membrane fusion proteins were upregulated. Three extracellular protease genes (vppC, prtA and VPA1071) and a dozen of outer membrane protein encoding genes were also significantly differentially expressed during biofilm formation. In addition, five putative c-di-GMP metabolism-associated genes were significantly differentially expressed, which may account for the drop in c-di-GMP levels after the beginning of biofilm formation. Moreover, many putative regulatory genes were significantly differentially expressed, and more than 1000 putative small non-coding RNAs were detected, suggesting that biofilm formation was tightly regulated by complex regulatory networks. The data provided a global view of gene expression profiles during biofilm formation, showing that the significantly differentially expressed genes were involved in multiple cellular pathways, including virulence, biofilm formation, metabolism, and regulation.}, } @article {pmid37838413, year = {2023}, author = {Stevenson, P and Marguet, M and Regulski, M}, title = {Biofilm and Hospital-Acquired Infections in Older Adults.}, journal = {Critical care nursing clinics of North America}, volume = {35}, number = {4}, pages = {375-391}, doi = {10.1016/j.cnc.2023.05.007}, pmid = {37838413}, issn = {1558-3481}, abstract = {Biofilm infections are a serious threat to public health, resistant to traditional treatments and host immune defenses. Biofilm infections are often polymicrobial, related to chronic wounds, medical devices (eg, knee replacements, catheters, tubes, contact lenses, or prosthetic valves) and chronic recurring diseases. Biofilms are more complex than nonadhered planktonic bacteria and produce a structure that prevents damage to the bacteria within the biofilm structure. The structure provides a hidden route to feed and nurture the bacteria allowing for ongoing spread of the bacteria.}, } @article {pmid37838341, year = {2023}, author = {El Mahmoudi, A and Tareau, AS and Barreau, M and Chevalier, S and Hourma, C and Demange, L and Benhida, R and Bougrin, K}, title = {Green synthesis and anti-biofilm activities of 3,5-disubstituted isoxazoline/isoxazole-linked secondary sulfonamide derivatives on Pseudomonas aeruginosa.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {}, number = {}, pages = {129517}, doi = {10.1016/j.bmcl.2023.129517}, pmid = {37838341}, issn = {1464-3405}, abstract = {The search for new classes of antibiotics is a real concern of public health due to the emergence of multi-resistant bacteria strains. We report herein the synthesis and characterization of a new series of 13 molecules combining isoxazoline/isoxazole sulfonamides and hydrazides motives. These molecules were obtained according to a costless eco-friendly procedure, and a one-pot three-step cascade synthesis under ultrasonic cavitation. All the synthesized compounds were fully characterized by HRMS, [1]H NMR, [13]C NMR spectroscopy and HPLC analysis. These new molecules have been evaluated against the major human opportunistic pathogen Pseudomonas aeruginosa to determine their potential to affect its growth and biofilm formation or dispersion. Two derivatives (5a and 6a) demonstrated their ability to destabilize a mature biofilm by about 50 % within 24 h. This may pave the way to the development of a new class of compounds affecting biofilm, which are easy to synthesize according to green chemistry processes.}, } @article {pmid37838199, year = {2023}, author = {Zhao, X and Xie, Y and Sun, B and Liu, Y and Zhu, S and Li, W and Zhao, M and Liu, D}, title = {Unraveling microbial characteristics of simultaneous nitrification, denitrification and phosphorus removal in a membrane-aerated biofilm reactor.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117402}, doi = {10.1016/j.envres.2023.117402}, pmid = {37838199}, issn = {1096-0953}, abstract = {This study describes the simultaneous removal of carbon, ammonium, and phosphate from domestic wastewater by a membrane-aerated biofilm reactor (MABR) which was operated for 360 days. During the operation, the maximum removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) reached 93.1%, 83.98%, and 96.41%, respectively. Statistical analysis showed that the MABR could potentially treat wastewater with a high ammonium concentration and a relatively low C/N ratio. Dissolved oxygen and multiple pollutants, including ammonium, carbon, phosphate, and sulfate, shaped the structure of the microbial community in the MABR. High throughput sequencing uncovered the crucial microbiome in ammonium transformation in MABR. Phylogenetic analysis of the ammonia monooxygenase (amoA) genes revealed an important role for comammox Nitrospira in the nitrification process. Diverse novel phosphate-accumulating organisms (Thauera, Bacillus, and Pseudomonas) and sulfur-oxidizing bacteria (Thiobacillus, Thiothrix and Sulfurimonas) were potentially involved in denitrification in MABR. The results from this study suggested that MABR could be a feasible system for the simultaneous removal of nitrogen, carbon, phosphorus, and sulfur from sewage water.}, } @article {pmid37838096, year = {2023}, author = {Santi, L and Berger, M and Guimarães, JA and Alves, YPC and Vainstein, MH and Yates, JR and Beys-da-Silva, WO}, title = {Proteomic profile of Cryptococcus gattii biofilm: Metabolic shift and the potential activation of electron chain transport.}, journal = {Journal of proteomics}, volume = {}, number = {}, pages = {105022}, doi = {10.1016/j.jprot.2023.105022}, pmid = {37838096}, issn = {1876-7737}, abstract = {Cryptococcus gattii is a primary pathogenic fungus that causes pneumonia. This species is also responsible for an outbreak in Vancouver, Canada, and spreading to the mainland and United States. The use of medical devices is often complicated by infections with biofilm-forming microbes with increased resistance to antimicrobial agents and host defense mechanisms. This study investigated the comparative proteome of C. gattii R265 (VGIIa) grown under planktonic and biofilm conditions. A brief comparison with C. neoformans H99 biofilm and the use of different culture medium and surface were also evaluated. Using Multidimensional Protein Identification Technology (MudPIT), 1819 proteins were identified for both conditions, where 150 (8.2%) were considered differentially regulated (up- or down-regulated and unique in biofilm cells). Overall, the proteomic approach suggests that C. gattii R265 biofilm cells are maintained by the induction of electron transport chain for reoxidation, and by alternative energy metabolites, such as succinate and acetate. SIGNIFICANCE: Since C. gattii is considered a primary pathogen and is one of the most virulent and less susceptible to antifungals, understanding how biofilms are maintained is fundamental to search for new targets to control this important mode of growth that is difficult to eradicate.}, } @article {pmid37836290, year = {2023}, author = {Taher, BB and Rasheed, TA}, title = {The Impact of Adding Chitosan Nanoparticles on Biofilm Formation, Cytotoxicity, and Certain Physical and Mechanical Aspects of Directly Printed Orthodontic Clear Aligners.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {13}, number = {19}, pages = {}, pmid = {37836290}, issn = {2079-4991}, abstract = {Aligner treatment is associated with bacterial colonization, leading to enamel demineralization. Chitosan nanoparticles have been demonstrated to have antibacterial properties. This in vitro study aims to determine the effect of adding chitosan nanoparticles to directly 3D-printed clear aligner resin with regard to antibiofilm activity, cytotoxicity, degree of conversion, accuracy, deflection force, and tensile strength. Different concentrations (2%, 3%, and 5% w/w) of chitosan nanoparticles were mixed with the clear resin, and the samples were then 3D printed. Additionally, the thermoforming technique for aligner manufacturing was utilized. The obtained specimens were evaluated for antibiofilm activity against Streptococcus mutans bacteria and cytotoxicity against L929 and 3T3 cell lines. Additionally, Fourier transform infrared spectroscopy via attenuated total reflection analysis was used to assess the degree of conversion. Geomagic Control X software was utilized to analyze the accuracy. In addition, the deflection force and tensile strength were evaluated. The results indicated a notable reduction in bacterial colonies when the resin was incorporated with 3 and 5% chitosan nanoparticles. No significant changes in the cytotoxicity or accuracy were detected. In conclusion, integrating biocompatible chitosan nanoparticles into the resin can add an antibiofilm element to an aligner without compromising the material's certain biological, mechanical, and physical qualities at specific concentrations.}, } @article {pmid37835326, year = {2023}, author = {Sloniker, N and Raftopoulou, O and Chen, Y and Ryser, ET and Beaudry, R}, title = {Fate of Planktonic and Biofilm-Derived Listeria monocytogenes on Unwaxed Apples during Air and Controlled Atmosphere Storage.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {19}, pages = {}, doi = {10.3390/foods12193673}, pmid = {37835326}, issn = {2304-8158}, support = {K2546//Center For Produce Safety/ ; }, abstract = {Multiple recalls and outbreaks involving Listeria monocytogenes-contaminated apples have been linked to the post-harvest packing environment where this pathogen can persist in biofilms. Therefore, this study assessed L. monocytogenes survival on apples as affected by harvest year, apple cultivar, storage atmosphere, and growth conditions. Unwaxed Gala, Granny Smith, and Honeycrisp apples were dip-inoculated in an 8-strain L. monocytogenes cocktail of planktonic- or biofilm-grown cells (~6.5 log CFU/mL), dried, and then examined for numbers of L. monocytogenes during air or controlled atmosphere (CA) (1.5% O2, 1.5% CO2) storage at 2 °C. After 90 days, air or CA storage yielded similar L. monocytogenes survival (p > 0.05), regardless of harvest year. Populations gradually decreased with L. monocytogenes quantifiable in most samples after 7 months. Apple cultivar significantly impacted L. monocytogenes survival (p < 0.05) during both harvest years with greater reductions (p < 0.05) seen on Gala compared to Granny Smith and Honeycrisp. Biofilm-derived cells survived longer (p < 0.05) on L. monocytogenes-inoculated Gala and Honeycrisp apples compared to cells grown planktonically. These findings should aid in the development of improved L. monocytogenes intervention strategies for apple growers and packers.}, } @article {pmid37835311, year = {2023}, author = {Zhu, W and Liu, J and Zou, Y and Li, S and Zhao, D and Wang, H and Xia, X}, title = {Anti-Biofilm Activity of Laurel Essential Oil against Vibrio parahaemolyticus.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {19}, pages = {}, doi = {10.3390/foods12193658}, pmid = {37835311}, issn = {2304-8158}, support = {2022YFD2100104//National Key Research and Development Program of China/ ; }, abstract = {Vibrio parahaemolyticus is a primary seafood-associated pathogen that could cause gastroenteritis. It can attach to various surfaces and form a biofilm, which poses serious threats to food safety. Hence, an effective strategy is urgently needed to control the biofilm formation of V. parahaemolyticus. Laurel essential oil (LEO) is used in food, pharmaceutical and other industries, and is commonly used as a flavoring agent and valuable spice in food industries. The potential antibiofilm effects of LEO against V. parahaemolyticus were examined in this study. LEO obviously reduced biofilm biomass at subinhibitory concentrations (SICs). It decreased the metabolic activity and viability of biofilm cells. Microscopic images and Raman spectrum indicted that LEO interfered with the structure and biochemical compositions of biofilms. Moreover, it also impaired swimming motility, decreased hydrophobicity, inhibited auto-aggregation and reduced attachment to different food-contact surfaces. RT-qPCR revealed that LEO significantly downregulated transcription levels of biofilm-associated genes of V. parahaemolyticus. These findings demonstrate that LEO could be potentially developed as an antibiofilm strategy to control V. parahaemolyticus biofilms in food industries.}, } @article {pmid37835254, year = {2023}, author = {Wang, L and Cao, X and Pei, H and Liu, P and Song, Y and Wu, Y}, title = {Anti-Biofilm Activity of Chlorogenic Acid against Pseudomonas Using Quorum Sensing System.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {19}, pages = {}, doi = {10.3390/foods12193601}, pmid = {37835254}, issn = {2304-8158}, support = {KZ202010011017//Beijing Natural Science Foundation and Beijing Municipal Education Committee/ ; NO. 21773014//National Natural Science Foundation of China/ ; }, abstract = {Chlorogenic acid is a secondary metabolite produced by many traditional Chinese medicines. Its physiological activities (antibacterial, anti-inflammatory, antioxidant activities, etc.) have been well described. This study aimed to investigate the effects of chlorogenic acid on the biofilm of drinking water bacteria. The effects of chlorogenic acid on the metabolites of the biofilms were also evaluated. Chlorogenic acid was found to have an anti-biofilm effect against Pseudomonas, resulting in biofilm formation in a dose-dependent manner (0.53-25.4 mM CGA). Moreover, the biofilm structure was visibly attenuated. Furthermore, we identified and characterized 23 differential metabolites and associated two metabolic pathways involving beta-alanine metabolism and pyrimidine metabolism that were altered mostly during biofilm formation. A quantitative real-time PCR assay revealed that chlorogenic acid interfered with the signaling molecule synthesis and transcription regulators using the Las, Pqs and Rhl systems. These findings suggest that chlorogenic acid can be a quorum sensing (QS) inhibitor and inhibit biofilm formation. It may be a promising natural product for the prevention of contaminated drinking water.}, } @article {pmid37833947, year = {2023}, author = {Hassanbhai, AM and Phoon, MC and Chow, VT and Ho, B}, title = {The Association of Helicobacter pylori Biofilm with Enterovirus 71 Prolongs Viral Viability and Survival.}, journal = {International journal of molecular sciences}, volume = {24}, number = {19}, pages = {}, doi = {10.3390/ijms241914500}, pmid = {37833947}, issn = {1422-0067}, support = {E57100081601//National University of Singapore/ ; }, abstract = {The transition time during which a virus leaves its host and infects the next susceptible host is critical for virus survival. Enterovirus 71 (EV71) is stable in aqueous environments, but its molecular interactions with bacteria and their biofilms are not well-established. Helicobacter pylori is a highly successful gut bacterial pathogen, with its capacity to form biofilms being linked to its transmission. Given that both are gut-associated microbes, we hypothesized that biofilms formed by H. pylori may play a significant role in the survival of EV71 in the external environment. In this study, we examine the interactions of EV71 with the preformed biofilm of H. pylori to mimic its natural state in the environment. Immunofluorescence confocal microscopy and scanning electron microscopy revealed that EV71 particles persisted for up to 10 days when incubated with the H. pylori biofilm. Furthermore, the presence of the H. pylori biofilm significantly augmented viral viability, as verified through virus plaque assays. Interestingly, the viability of EV71 was dependent on the quantity of H. pylori biofilm formation. Thus, two H. pylori strains able to generate large amounts of biofilm could facilitate EV71 viability for up to 17 days, whereas two other H. pylori strains that produced moderate or low quantities of biofilm could not prolong virus viability. It is interesting that biofilm contains N-acetyl-glucosamine and glycosaminoglycan, and that EV71 has binding affinity to cell-surface heparan sulfate glycosaminoglycan, which acts as an EV71 attachment receptor. The synergistic ability of H. pylori biofilm to promote EV71 viability for extended periods implies that H. pylori biofilm may serve as an additional pathway of EV71 transmission.}, } @article {pmid37832891, year = {2023}, author = {Wang, H and Guan, F and Zhu, Y and Pan, Y and Liu, Q and Liu, Q and He, W and Gong, D and Tian, J and Han, D}, title = {Biofilm formation promoted biodegradation of polyethylene in Gordonia polyisoprenivorans B251 isolated from bacterial enrichment acclimated by hexadecane for two years.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140383}, doi = {10.1016/j.chemosphere.2023.140383}, pmid = {37832891}, issn = {1879-1298}, abstract = {Polyethylene (PE) mulch films have been widely used in agriculture and led to a significant pollution in cultivated soils. It is desirable to develop the sustainable method for the degradation of PE. As an environment friendly approach, microbial or enzymatic degradation of PE could meet this demanding. Thus, more microbial strains are required for illustrating biodegrading pathway and developing efficient biological method. In this study, Gordonia polyisoprenivorans B251 capable of degrading PE was isolated from bacterial enrichment with hexadecane as a sole carbon source for two years, in which genus Gordonia had dominated. As revealed by microbial growth curve, the strain B251 had the highest growth rate than other tested strains in the mediums either with hexadecane or PE particles as sole carbon source. The formation of biofilms in both enriched culture and G. polyisoprenivorans B251 pure culture attached to PE film was observed. The capability for PE degradation of individual strain was screened by 30-day incubation with PE film and confirmed by the presence of hydroxyl, carbonyl, carbon-carbon double bond and ether groups in FT-IR analysis and cracks on the surface of PE film observed by scanning electron microscopy (SEM). Therefore, Gordonia polyisoprenivorans, reported as their degradation of environmental contaminants in previous study, were also identified in current study as a candidate for polyethylene biodegradation.}, } @article {pmid37832880, year = {2023}, author = {Zhang, C and Dong, Z and Chen, Q and Lin, Y and Zhou, Y and Xu, Q}, title = {Determination of key factors affecting biofilm formation on the aged Poly(ethylene terephthalate) during anaerobic digestion.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140435}, doi = {10.1016/j.chemosphere.2023.140435}, pmid = {37832880}, issn = {1879-1298}, abstract = {Biofilm formation on plastic surface is a growing concern because it can alter the plastic surface properties and exacerbate the ecological risk. Identifying key factors that affecting biofilm formation is critical for effective pollution control. In this study, the poly (ethylene terephthalate) (PET) was aged in water and air conditions with UV irradiation, then incubated in the digestate of food waste anaerobic digestion to allow biofilm formation. Surface analysis techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), were utilized to investigated the changes in the topography, roughness, hydrophily, and functional groups change of the PET surface during the aging process. Confocal laser scanning microscopy (CLSM) was used to determine the distribution of microorganisms on the PET surface after incubation in the digestate. This study focused on understanding the interactions between the PET surface and biofilm to identify critical surface factors that affect biofilm formation. Results showed that the four months aging process decreased the contact angle of the PET surface from 96.92° to 76.08° and 68.97° in water and air conditions, respectively, corresponding to an increase of 44% and 70% in the surface energy. Additionally, aging in air conditions led to a rougher surface compared to water conditions. The arithmetic roughness average (Ra) of the PET-Water was 11.0 nm, comparable to that of the pristine PET, while the value of PET-Air was much higher (43.9 nm). The results further indicated that biofilm formation during anaerobic digestion was more sensitive to roughness than hydrophily. The PET surface aged in air conditions provided a more suitable environment for microbial reproduction, leading to the aggradation of living cells.}, } @article {pmid37832348, year = {2023}, author = {Zhao, H and Zang, Y and Xie, B and Zhao, T and Cao, B and Wu, J and Ge, Y and Yi, Y and Liu, H}, title = {Instant water toxicity detection based on magnetically-constructed electrochemically active biofilm.}, journal = {Biosensors & bioelectronics}, volume = {242}, number = {}, pages = {115745}, doi = {10.1016/j.bios.2023.115745}, pmid = {37832348}, issn = {1873-4235}, abstract = {Water toxicity determination with electrochemically active bacteria (EAB) is promising in the early warning of water pollution. However, limited by tedious biofilm formation, natural EAB biofilms are uncapable of the instant detection of water toxicity, resulting in the failure for the emergency monitoring of water pollution. To solve this problem, a novel method for the rapid construction of EAB biofilms using magnetic adsorption was established, and the performance of instant water toxicity detection with magnetically-constructed EAB biofilm was investigated. The results demonstrate that EAB biofilms were magnetically constructed in less than 30 min, and magnetically-constructed EAB biofilm generated stable currents even under continuous flow conditions. Magnetically-constructed EAB biofilms realized instant water toxicity detection, and the sensitivity increased with the decrease of magnetic field intensity. Low magnetic field intensity resulted in a loose biofilm structure, which is conducive to toxic pollutant penetration. The detection limit for Cu[2+], phenol, and Cd[2+] achieved 0.07 mg/L with optimal magnetic field intensity, and the detection time was less than 30 min. This study broadens the application of water toxicity determination with EAB, and establishes a foundation for the instant and continuous detection of water toxicity with EAB.}, } @article {pmid37832779, year = {2023}, author = {Zhang, T and Li, K and Liu, X}, title = {DBP-FP change of biofilm in drinking water distribution system induced by sequential UV and chlorine disinfection: Effect of UV dose and influencing mechanism.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122716}, doi = {10.1016/j.envpol.2023.122716}, pmid = {37832779}, issn = {1873-6424}, abstract = {The issue of biofilm-related disinfection byproducts (DBPs) in drinking water distribution system (DWDS) has garnered significant attention. This study sought to examine the changes in biofilm-originated halogenated DBP formation potential (biofilm DBP-FP) in simulated continuous-flow DWDSs subjected to sequential UV and chlorine disinfection (UV-Cl2) treatments with varying UV doses and to propose the underlying mechanism. The formation potential of trihalomethanes (THMs), haloacetic acids (HAAs), and the total organic halogen (TOX, X = Cl and Br) produced by biofilm were measured. Results showed that the biofilm TOCl-FP was at a minimum with a UV dose of 80 mJ/cm[2], corresponding to the lowest amounts of protein and polysaccharides in the extracellular polymeric substances (EPS). Sphingobium, Methylobacterium, and Sphingomonas played a crucial role in protein and polysaccharide biosynthesis. Bacterial community composition characterization together with metabolic function analysis indicated that dominant bacteria varied and metabolic function shifted due to UV-Cl2 disinfection, with Alphaproteobacteria increasing in relative abundance and Bacteroidia showing the opposite trend with increasing UV doses. Correlation analysis suggested that the UV-Cl2 disinfection process led to changes in the water matrix, including organics, inorganics, bacteria, and components that provide environmental pressure for the biofilm. These changes ultimately influenced the properties of the biofilm EPS, which had a direct impact on biofilm DBP-FP.}, } @article {pmid37832710, year = {2023}, author = {Dahshan, NA and Abu-Dahab, RM and Khalil, EA and Al-Bakri, AG}, title = {Bactericidal Effect of Iberin Combined with Photodynamic Antimicrobial Chemotherapy Against Pseudomonas aeruginosa Biofilm Cultured on ex vivo Wound Model.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {}, number = {}, pages = {103841}, doi = {10.1016/j.pdpdt.2023.103841}, pmid = {37832710}, issn = {1873-1597}, abstract = {Wounds infected by Pseudomonas aeruginosa (P. aeruginosa) biofilms are characterized by poor healing and by being long lasting. Pyocyanin and pyoverdine are exotoxins that contribute to P. aeruginosa pathogenicity in wound infections and are known as virulence factors. Despite the usefulness of photodynamic antimicrobial chemotherapy (PDT) in the management of wound infections, biofilms are hurdle for microbial photoinactivation. Quorum sensing (QS) is a cell density-dependent chemical signaling system P. aeruginosa uses to regulate biofilm formation and virulence factors production. In the current study, QS attenuation was used in combination with PDT against P. aeruginosa biofilm cultured on skin explant. Iberin is a QS inhibitor that attenuates P. aeruginosa virulence and affects biofilm integrity. The antibiofilm and QS inhibitory activities of iberin in combination with either riboflavin or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio) porphyrin tetra p-toluenesulfonate (TMP) mediated PDT were investigated using viable count method and pyocyanin and pyoverdine assays, respectively. No bactericidal activity was reported when iberin was added to a mature biofilm (24 h) followed by PDT. When added to a growing biofilm at multiple time points (0 h, 24 h and 48 h), iberin inhibited P. aeruginosa biofilm QS signaling system. This inhibitory effect resulted in an observable decrease in the levels of the QS-regulated virulence factors, pyocyanin and pyoverdine, without any effect on the growth of the biofilm cultures. These changes in biofilm virulence were associated with a decrease in biofilm resistance to PDT and caused bactericidal effect upon photosensitizers treatment and irradiation. Iberin-treated-riboflavin-mediated PDT resulted in a significant 1.3 log reduction in biofilm population. Similarly, iberin-treated-TMP-mediated PDT caused a significant 1.8 log reduction in biofilm population. The combination of QS inhibitor with PDT is a promising alternative antimicrobial therapy for the management of biofilms.}, } @article {pmid37831630, year = {2023}, author = {Simsekli, O and Bilinmis, I and Celik, S and Arık, G and Baba, AY and Karakucuk, A}, title = {Advancing Biofilm Management through Nanoformulation Strategies: A Review of Dosage Forms and Administration Routes.}, journal = {Journal of drug targeting}, volume = {}, number = {}, pages = {1-64}, doi = {10.1080/1061186X.2023.2270619}, pmid = {37831630}, issn = {1029-2330}, abstract = {Biofilms are complex microbial communities formed by the attachment of bacteria or fungi to surfaces encased in a self-produced polymeric matrix. These biofilms are highly resistant to conventional antimicrobial therapies. The resistance mechanisms exhibited by biofilms include low antibiotic absorption, sluggish replication, adaptive stress response, and the formation of dormant-like phenotypes. The eradication of biofilms requires alternative strategies and approaches. Nanotechnological drug delivery systems allow excellent control over the drug chemistry, surface area, particle size, particle shape, and composition of nanostructures. Nanoformulations can enhance the efficacy of antimicrobial agents by improving their bioavailability, stability, and targeted delivery to the site of infection that, helps biofilm eradication more effectively.In addition to nanoformulations, the route of administration and choice of dosage forms play a crucial role in treating biofilm infections. Systemic administration of antibiotics is effective in controlling systemic infection and sepsis associated with biofilms. Alternative routes of administration, such as inhalation, vaginal, ocular, or dermal, have been explored to target biofilm infections in specific organs.This review primarily examines the utilization of nanoformulations in various administration routes for biofilm management. It also provides an overview of biofilms, current approaches, and the drawbacks associated with conventional methods.}, } @article {pmid37831285, year = {2023}, author = {Márton, R and Nagy, B and Molnár, M}, title = {Biofilm development of Candida boidinii and the effect of tyrosol on biofilm formation.}, journal = {Biotechnology letters}, volume = {}, number = {}, pages = {}, pmid = {37831285}, issn = {1573-6776}, support = {Richter Gedeon Talentum Foundation//Richter Gedeon Talentum Foundation/ ; TKP2021-EGA-02//Nemzeti Kutatási, Fejlesztési és Innovaciós Alap/ ; }, abstract = {OBJECTIVES: The applicability of a simple and high-throughput method for quantitative characterization of biofilm formation by Candida boidinii was tested in order to evaluate the effects of exogenous tyrosol on yeast growth and biofilm formation capacity.

RESULTS: Significant concentration-, temperature and time-dependent effect of tyrosol (2-(4-hydroxyphenyl)ethanol) was demonstrated, but it differentially affected the growth and biofilm formation (characterized by crystal violet staining and XTT-reduction assay) of Candida boidinii. Testing biofilm based on metabolic activity displayed sensitively the differences in the intensity of biofilm in terms of temperature, tyrosol concentration, and exposure time. At 22 °C after 24 h none of the tyrosol concentrations had significant effect, while at 30 °C tyrosol-mediated inhibition was observed at 50 mM and 100 mM concentration. After 48 h and 72 h at 22 °C, biofilm formation was stimulated at 6.25-25 mM concentrations, meanwhile at 30 °C tyrosol decreased the biofilm metabolic activity proportionally with the concentration.

CONCLUSIONS: The research concludes that exogenous tyrosol exerts unusual effects on Candida boidinii growth and biofilm formation ability and predicts its potential application as a regulating factor of various fermentations by Candida boidinii.}, } @article {pmid37831271, year = {2023}, author = {Suthi, S and Mounika, A and Potukuchi, VGKS}, title = {Elevated acetate kinase (ackA) gene expression, activity, and biofilm formation observed in methicillin-resistant strains of Staphylococcus aureus (MRSA).}, journal = {Journal, genetic engineering & biotechnology}, volume = {21}, number = {1}, pages = {100}, pmid = {37831271}, issn = {2090-5920}, abstract = {BACKGROUND: Staphylococcus aureus spreads its infections through biofilms. This usually happens in the stationary phase of S. aureus growth where it utilizes accumulated acetate as a carbon source via the phosphotrans-acetylase-acetate kinase (Pta-Ack) pathway. In which acetate kinase (ackA) catalyzes the substrate-level phosphorylation, a vital secondary energy-yielding pathway that promotes biofilms formation aids bacterium survival in hostile environments. In this study, we describe the cloning, sequencing, and expression of S. aureus ackA gene. The expression analysis of ackA gene in methicillin-resistant strains of S. aureus (MRSA) correlates with ackA activity and biofilm units. The uniqueness of ackA was analyzed by using in silico methods.

RESULTS: Elevated ackA gene expression was observed in MRSA strains, which correlates with increased ackA activity and biofilm units, explaining ackA role in MRSA growth and pathogenicity. The pure recombinant acetate kinase showed a molecular weight of 44 kDa, with enzyme activity of 3.35 ± 0.05 μM/ml/min. The presence of ACKA-1, ACKA-2 sites, one ATP, and five serine/threonine-protein kinase sites in the ackA gene (KC954623.1) indicated that acetyl phosphate production is strongly controlled. The comparative structural analysis of S. aureus ackA with ackA structures of Mycobacterium avium (3P4I) and Salmonella typhimurium (3SLC) exhibited variations as indicated by the RMSD values 1.877 Å and 2.141 Å respectively, explaining why ackA functions are differently placed in bacteria, concurring its involvement in S. aureus pathogenesis.

CONCLUSIONS: Overall findings of this study highlight the correlation of ackA expression profoundly increases survival capacity through biofilm formation, which is a pathogenic factor in MRSA and plays a pivotal role in infection spreading.}, } @article {pmid37830811, year = {2023}, author = {Castro, C and Ndukwe, I and Heiss, C and Black, I and Ingel, BM and Guevara, M and Sun, Y and Azadi, P and Sun, Q and Roper, MC}, title = {Xylella fastidiosa modulates exopolysaccharide polymer length and the dynamics of biofilm development with a β-1,4-endoglucanase.}, journal = {mBio}, volume = {}, number = {}, pages = {e0139523}, doi = {10.1128/mbio.01395-23}, pmid = {37830811}, issn = {2150-7511}, abstract = {Xylella fastidiosa is a Gram-negative bacterium that causes disease in many economically important crops. It colonizes the plant host xylem and the mouthparts of its insect vectors where it produces exopolysaccharide (EPS) and forms robust biofilms. Typically, the ability to form a biofilm enhances virulence, but X. fastidiosa does not fit neatly into that paradigm. Instead, X. fastidiosa enters into biofilms to attenuate its movement in the xylem, which, in turn, slows disease progression. In most of its over 600 known plant hosts, X. fastidiosa behaves as a benign commensal, but in some hosts like Vitis vinifera grapevines, it acts as a pathogen. Its ability to attenuate its own virulence in susceptible hosts may be a remnant of its commensal lifestyle in other hosts. Here, we demonstrate that X. fastidiosa utilizes a β-1,4 endoglucanase to cleave its self-produced β-1,4-glucan exopolysaccharide polymer to process it from a higher molecular weight to a lower molecular weight polymer. This processing mediates surface adherence of the cells and ultimately governs overall biofilm architecture, indicating enzymatic pruning of the EPS plays a key role in biofilm-mediated attenuation of X. fastidiosa in planta and, thus, is a key vestige that links its commensal behaviors to its parasitic behaviors in specific hosts. IMPORTANCE It is well established that exopolysaccharide (EPS) is an integral structural component of bacterial biofilms necessary for assembly and maintenance of the three-dimensional architecture of the biofilm. However, the process and role of EPS turnover within a developing biofilm is not fully understood. Here, we demonstrated that Xylella fastidiosa uses a self-produced endoglucanase to enzymatically process its own EPS to modulate EPS polymer length. This enzymatic processing of EPS dictates the early stages of X. fastidiosa's biofilm development, which, in turn, affects its behavior in planta. A deletion mutant that cannot produce the endoglucanase was hypervirulent, thereby linking enzymatic processing of EPS to attenuation of virulence in symptomatic hosts, which may be a vestige of X. fastidiosa's commensal behavior in many of its other non-symptomatic hosts.}, } @article {pmid37830790, year = {2023}, author = {Lemus, AA and Valm, AM}, title = {In Vitro Dental Plaque Culture Model for Biofilm Structural Analyses.}, journal = {Current protocols}, volume = {3}, number = {10}, pages = {e902}, doi = {10.1002/cpz1.902}, pmid = {37830790}, issn = {2691-1299}, support = {R01DE030927/DE/NIDCR NIH HHS/United States ; }, abstract = {Extensive research has focused on the compositional changes in dental plaque microbiome communities during the transition from health to disease, known as dysbiosis. However, alterations in the spatial composition of these communities throughout the progression from health to disease remain under-explored. We describe an in vitro dental plaque model for culturing oral biofilms seeded with dental plaque from human volunteers. Our model recapitulates important features of the in vivo environment including shear force induced by salivary flow over teeth and the nutritional milieu experienced by microbes that inhabit the transitional zone between supragingival and subgingival aspects of the teeth. Importantly, our model is amenable to multiplex fluorescent labeling and multispectral imaging for testing specific hypotheses regarding systems-level community structure and function. The model allows for precise manipulation of various environmental conditions, such as flow rate and nutrient availability to investigate their effects on biofilm development and spatial structure. Furthermore, this model can be used to test the effects of various therapeutic interventions, e.g., antimicrobial agents, on the biofilm composition and structure at the micron to millimeter scale, making it a valuable tool for studying the molecular and cellular basis of dental plaque-mediated diseases and for benchmarking new therapeutic interventions. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Dental plaque-on-a-chip in vitro model culture system Support Protocol: Gingival margin (GM) medium preparation Basic Protocol 2: Microcosm labeling and multispectral image acquisition.}, } @article {pmid37829251, year = {2023}, author = {Chavak, Z and Mahdian, N and Pakzad, I and Soltani, MR and Badakhsh, B and Ghafourian, S}, title = {In vitro anti-biofilm properties of the peel of fruite wall of acorn against Streptococcus mutans.}, journal = {GMS hygiene and infection control}, volume = {18}, number = {}, pages = {Doc23}, pmid = {37829251}, issn = {2196-5226}, abstract = {Dental caries is a multi-factorial infectious disease. The primary cause is dental plaque, a complex of biofilm. It was postulated that the ethanolic extract of fruite wall of acorn may represent a new substance to prevent caries. Hence, the study was performed to evaluate the effect of ethanolic extract of fruite wall of acorn against biofilm formation by Streptococcus mutans, which is associated with dental plaque. The cytotoxicity of the ethanolic extract was determined against Vero cells resulting in an inhibitory concentration of 50 (IC50) of 55 µg/ml. After bacterial collection, different concentrations under the IC50 from the extract were evaluated against biofilm formation of S. mutans. 3 µg/ml of the extract inhibited the biofilm formation of S. mutans, and 1 to 3 µg/ml caused a decrease in gtfB and brpA biofilm-production genes. This study showed the potency of the ethanolic extract of fruite wall of acorn against biofilm formation by S. mutans.}, } @article {pmid37827320, year = {2023}, author = {Ren, X and Zhang, S and Wu, M and Xiao, B and Miao, H and Chen, H}, title = {Effect and influence mechanism of biofilm formation on the biological stability of reclaimed water.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167735}, doi = {10.1016/j.scitotenv.2023.167735}, pmid = {37827320}, issn = {1879-1026}, abstract = {Microorganisms and sediments in reclaimed water adhere to the inner walls of pipes or water tanks, forming biofilms that support the continuous growth of microorganisms. These biofilms provide a protective barrier, shielding bacteria from disinfectants. This study investigated the impact of biofilms on bacterial growth and reproduction in reclaimed water and the factors limiting bacterial growth in reclaimed graywater (GMR) and reclaimed mixed wastewater (MWR). The results revealed that biofilm biomass gradually increased and reached a maximum value on Days 20-25, and the biomass of organisms continued to decrease after 40 days. Biofilms serve as a source of bacteria, continuously releasing them into reclaimed water systems. The presence of biofilms reduced the biological stability of the reclaimed water, leading to water quality deterioration. The concentration of assimilable organic carbon in the reclaimed water showed a positive correlation with the heterotrophic bacterial count and Escherichia coli levels in both the reclaimed water and biofilms. The threshold value of chlorine for inhibiting biofilms in reclaimed water was no <2 mg/L. High concentrations of free chlorine delayed the growth of biofilms but did not reduce the final biomass generated by the biofilms. Carbon was the limiting factor for the biological stability of reclaimed water, while nitrogen, phosphorus, and inorganic salts were not limiting factors. Thus, minimizing the concentration of organic matter in reclaimed water can reduce the nutrient sources available for biofilm formation. This study provides support for advancements in the wastewater reuse industry.}, } @article {pmid37827053, year = {2023}, author = {Yang, G and Fan, R and Yang, J and Yi, L and Chen, S and Wan, W}, title = {Magnesium/gallic acid bioMOFs laden carbonized mushroom aerogel effectively heals biofilm-infected skin wounds.}, journal = {Biomaterials}, volume = {302}, number = {}, pages = {122347}, doi = {10.1016/j.biomaterials.2023.122347}, pmid = {37827053}, issn = {1878-5905}, abstract = {Biofilm-infected acute skin wounds are still one of the significant challenges that need to be solved urgently in wound healing. Herein, we reported a magnesium/gallic acid bio-MOFs laden carbonized mushroom aerogel (QMOFs-PCMA) combined with photothermal therapy for eradicating biofilms in skin wounds. The design of bioMOFs is mainly responsible for regulating immunity. In vitro, it exhibited ROS clearance and antioxidant ability. In vivo, it could regulate local immune responses from pro-inflammatory status to pro-regenerative status, resulting in decreased inflammatory cytokines expression and increased anti-inflammatory cytokines expression. The carbonized mushroom aerogel is mainly responsible for photothermal therapy (PTT), and the polydopamine and bioMOFs could enhance the photothermal conversion efficiency and stability of carbonized aerogels. The carbonized aerogel in combination with PTT could eradicate S. aureus biofilm in both in vitro and in vivo studies and clear E. coli biofilms in vitro studies. The biofilm clearance and improved inflammatory responses laid a good foundation for wound healing, resulting in the granulation tissue formation, re-epithelialization, and angiogenesis significantly enhanced in the QMOFs-PCMA + NIR group. Our results indicate that the QMOFs-PCMA combined with photothermal therapy may provide a promising treatment for biofilm-infected skin wounds.}, } @article {pmid37827037, year = {2023}, author = {Yu, J and You, J and Lens, PNL and Lu, L and He, Y and Ji, Z and Chen, J and Cheng, Z and Chen, D}, title = {Biofilm metagenomic characteristics behind high coulombic efficiency for propanethiol deodorization in two-phase partitioning microbial fuel cell.}, journal = {Water research}, volume = {246}, number = {}, pages = {120677}, doi = {10.1016/j.watres.2023.120677}, pmid = {37827037}, issn = {1879-2448}, abstract = {Hydrophobic volatile organic sulfur compounds (VOSCs) are frequently found during sewage treatment, and their effective management is crucial for reducing malodorous complaints. Microbial fuel cells (MFC) are effective for both VOSCs abatement and energy recovery. However, the performance of MFC on VOSCs remains limited by the mass transfer efficiency of MFC in aqueous media. Inspired by two-phase partitioning biotechnology, silicone oil was introduced for the first time into MFC as a non-aqueous phase (NAP) medium to construct two-phase partitioning microbial fuel cell (TPPMFC) and augment the mass transfer of target VOSCs of propanethiol (PT) in the liquid phase. The PT removal efficiency within 32 h increased by 11-20% compared with that of single-phase MFC, and the coulombic efficiency of TPPMFC (11.01%) was 4.32-2.68 times that of single-phase MFC owing to the fact that highly active desulfurization and thiol-degrading bacteria (e.g., Pseudomonas, Achromobacter) were attached to the silicone oil surface, whereas sulfur-oxidizing bacteria (e.g., Thiobacillus, Commonas, Ottowia) were dominant on the anodic biofilm. The outer membrane cytochrome-c content and NADH dehydrogenase activity improved by 4.15 and 3.36 times in the TPPMFC, respectively. The results of metagenomics by KEGG and COG confirmed that the metabolism of PT in TPPMFC was comprehensive, and that the addition of a NAP upregulates the expression of genes related to sulfur metabolism, energy generation, and amino acid synthesis. This finding indicates that the NAP assisted bioelectrochemical systems would be promising to solve mass-transfer restrictions in low solubility contaminates removal.}, } @article {pmid37826899, year = {2023}, author = {Beiki, V and Naseri, T and Mousavi, SM}, title = {An efficient approach for enhancement of gold and silver bioleaching from spent telecommunication printed circuit boards using cyanogenic bacteria: Prevention of biofilm formation.}, journal = {Waste management (New York, N.Y.)}, volume = {171}, number = {}, pages = {590-598}, doi = {10.1016/j.wasman.2023.10.007}, pmid = {37826899}, issn = {1879-2456}, abstract = {Environmentally friendly bioleaching of gold and silver from electronic waste using cyanogenic bacteria has emerged as a promising approach. In the process of cyanide bioleaching, cyanide ions produced by cyanogenic bacteria form complexes (such as AuCN and AgCN) with metals in the waste structure and lead to their dissolution. The recovery rate of these valuable elements during bioleaching is influenced by extracellular polymeric substances (EPS). For the first time, this study presents an investigation into the role of EPS from Pseudomonas atacamensis in the bioleaching of gold and silver from spent telecommunication printed circuit boards (STPCBs). The experimental results demonstrate that, after 6 days of bioleaching, gold and silver recoveries reached 22% and 36.2%, respectively. Complementary analyses employing FE-SEM and attachment tests shed light on the interactions between EPS, bacterial attachment to particle surfaces, and biofilm development stages during gold and silver bioleaching. Notably, the most significant bacterial attachment occurred on the fourth day of bioleaching. Zeta potential tests conducted on bacteria and EPS provided insights into the potential absorption of soluble cations such as Au[+] and Ag[+] by EPS. Furthermore, 250 mg/L polyvinylpyrrolidone (PVP) effectively removed EPS from the particle surfaces, improving gold and silver recovery rates, reaching 26% and 43.2%, respectively. These findings highlight the importance of understanding the role of EPS in bioleaching processes and offer insights into enhancing gold and silver recovery from electronic waste.}, } @article {pmid37824024, year = {2023}, author = {Jonblat, S and As-Sadi, F and Zibara, K and Sabban, ME and Dermesrobian, V and Khoury, AE and Kallassy, M and Chokr, A}, title = {Staphylococcus epidermidis biofilm assembly and self-dispersion: bacteria and matrix dynamics.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37824024}, issn = {1618-1905}, abstract = {Staphylococcus epidermidis, despite being a commensal of human skin and mucosa, is a major nosocomial pathogen implicated in device-associated infections. The dissemination of infection to other body sites is related to biofilm dispersal. This study focused on the dispersion stage of S. epidermidis CIP 444 biofilm, with the assessment of biofilm matrix composition in a time-dependent experiment (7 days extended) with 3 independent repetitions, using confocal laser scanning microcopy (CLSM) in association with ZEN 3.4 blue edition, COMSTAT, and ImageJ software. SYTO-9, propidium iodide (PI), DID'OIL, FITC, and calcofluor white M2R (CFW) were used to stain biofilm components. The results indicated that the biomass of dead cells increased from 15.18 ± 1.81 µm[3]/µm[2] (day 3) to 23.15 ± 6.075 µm[3]/µm[2] (day 4), along with a decrease in alive cells' biomass from 22.75 ± 2.968 µm[3]/µm[2] (day 3) to 18.95 ± 5.713 µm[3]/µm[2] (day 4). When the intensities were measured after marking the biofilm components, in a 24-h-old biofilm, polysaccharide made up the majority of the investigated components (52%), followed by protein (18.9%). Lipids make up just 11.6% of the mature biofilm. Protein makes up the largest portion (48%) of a 4-day-old biofilm, followed by polysaccharides (37.8%) and lipids (7.27%). According to our findings, S. epidermidis CIP 444 dispersion occurred on day 4 of incubation, and new establishment of the biofilm occurred on day 7. Remarkable changes in biofilm composition will pave the way for a new approach to understanding bacterial strategies inside biofilms and finding solutions to their impacts in the medical field.}, } @article {pmid37822746, year = {2023}, author = {Zhang, M and Cai, L and Luo, X and Li, X and Zhang, T and Wu, F and Zhang, Y and Lu, R}, title = {Effect of sublethal dose of chloramphenicol on biofilm formation and virulence in Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1275441}, pmid = {37822746}, issn = {1664-302X}, abstract = {Vibrio parahaemolyticus isolates are generally very sensitive to chloramphenicol. However, it is usually necessary to transfer a plasmid carrying a chloramphenicol resistance gene into V. parahaemolyticus to investigate the function of a specific gene, and the effects of chloramphenicol on bacterial physiology have not been investigated. In this work, the effects of sublethal dose of chloramphenicol on V. parahaemolyticus were investigated by combined utilization of various phenotypic assays and RNA sequencing (RNA-seq). The results showed that the growth rate, biofilm formation capcity, c-di-GMP synthesis, motility, cytoxicity and adherence activity of V. parahaemolyticus were remarkably downregulated by the sublethal dose of chloramphenicol. The RNA-seq data revealed that the expression levels of 650 genes were significantly differentially expressed in the response to chloramphenicol stress, including antibiotic resistance genes, major virulence genes, biofilm-associated genes and putative regulatory genes. Majority of genes involved in the synthesis of polar flagellum, exopolysaccharide (EPS), mannose-sensitive haemagglutinin type IV pilus (MSHA), type III secretion systems (T3SS1 and T3SS2) and type VI secretion system 2 (T6SS2) were downregulated by the sublethal dose of chloramphenicol. Five putative c-di-GMP metabolism genes were significantly differentially expressed, which may be the reason for the decrease in intracellular c-di-GMP levels in the response of chloramphenicol stress. In addition, 23 genes encoding putative regulators were also significantly differentially expressed, suggesting that these regulators may be involved in the resistance of V. parahaemolyticus to chloramphenicol stress. This work helps us to understand how chloramphenicol effect on the physiology of V. parahaemolyticus.}, } @article {pmid37822740, year = {2023}, author = {Enan, G and Abdel-Shafi, S and El-Nemr, M and Shehab, W and Osman, A and Sitohy, M and Sitohy, B}, title = {Controlling bacterial biofilm formation by native and methylated lupine 11S globulins.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1259334}, pmid = {37822740}, issn = {1664-302X}, abstract = {The antibacterial and anti-biofilm activities of the 11S globulins isolated from lupin seeds (Lupinus termis), and its methylated derivative (M11S), were investigated against seven pathogenic gram-positive and gram-negative bacteria. The MIC of 11S ranged from 0.1 to 4.0 μg/ml against 0.025 to 0.50 μg/ml for M11S, excelling some specific antibiotics. The MICs of M11S were 40-80 times lower than some specific antibiotics against gram-positive bacteria and 2-60 times lower than some specific antibiotics against gram-negative bacteria. One MIC of 11S and M11S highly reduced the liquid growth of all tested bacteria during 24 h at 37°C. They also inhibited biofilm formation by 80%-86% and 85%-94%, respectively (gram-positive), and 29%-44% and 43%-50%, respectively (gram-negative). M11S prevented biofilm formation by gram-positive bacteria at minimum biofilm inhibitory concentration (MBIC), 0.025-0.1 μg/ml against 0.1-0.5 μg/ml for gram-negative bacteria, i.e., 4-20 times and 4-7 times anti-biofilm inhibitory action compared with 11S, respectively. Biofilm formation of two bacteria revealed no adhered cells on glass slides for 24 h at 37°C, i.e., was entirely prevented by one MBIC of 11S and M11S. Scanning electron microscopy indicated microbial biofilm deformation under the action of 11S and M11S, indicating their broad specificity and cell membrane-targeted action.}, } @article {pmid37822738, year = {2023}, author = {Jiang, S and Zha, Y and Zhao, T and Jin, X and Zhu, R and Wei, S and Wang, R and Song, Y and Li, L and Lyu, J and Hu, W and Zhang, D and Wang, M and Zhang, Y}, title = {Antimicrobial peptide temporin derivatives inhibit biofilm formation and virulence factor expression of Streptococcus mutans.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1267389}, pmid = {37822738}, issn = {1664-302X}, abstract = {INTRODUCTION: Temporin-GHa obtained from the frog Hylarana guentheri showed bactericidal efficacy against Streptococcus mutans. To enhance its antibacterial activity, the derived peptides GHaR and GHa11R were designed, and their antibacterial performance, antibiofilm efficacy and potential in the inhibition of dental caries were evaluated.

METHODS: Bacterial survival assay, fluorescent staining assay and transmission electron microscopy observation were applied to explore how the peptides inhibited and killed S. mutans. The antibiofilm efficacy was assayed by examining exopolysaccharide (EPS) and lactic acid production, bacterial adhesion and cell surface hydrophobicity. The gene expression level of virulence factors of S. mutans was detected by qRT-PCR. Finally, the impact of the peptides on the caries induced ability of S. mutans was measured using a rat caries model.

RESULTS: It has been shown that the peptides inhibited biofilm rapid accumulation by weakening the initial adhesion of S. mutans and reducing the production of EPS. Meanwhile, they also decreased bacterial acidogenicity and aciduricity, and ultimately prevented caries development in vivo.

CONCLUSION: GHaR and GHa11R might be promising candidates for controlling S. mutans infections.}, } @article {pmid37819121, year = {2023}, author = {Zhang, J and Shen, L and Zhou, P and Chen, S and Wang, B and Wan, C and Han, W and Rao, L and Zhao, H and Wang, X and Wu, C and Shi, J and Xiao, Y and Song, Z and Yu, F and Lin, C}, title = {A novel small-molecule compound S-342-3 effectively inhibits the biofilm formation of Staphylococcus aureus.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0159623}, doi = {10.1128/spectrum.01596-23}, pmid = {37819121}, issn = {2165-0497}, abstract = {Staphylococcus aureus is an important human pathogen in both community and hospital settings that often causes persistent and recurrent infections. The continuous emergence of multidrug-resistant strains and the lag in antibiotic development make the treatment of S. aureus more challenging. The biofilm formation of S. aureus is an important reason for persistent infection. In this study, we demonstrated that a small-molecule compound S-342-3 can effectively inhibit the biofilm formation of S. aureus. The crystal violet semi-quantitative assays revealed that at a sub-minimum inhibitory concentration of 4 µg/mL, S-342-3 reduced S. aureus biofilm mass by 57.43%, 52.14%, and 25.49%. Using confocal laser scanning microscopy, we observed that the biofilm was more incompact and less uniform upon the treatment of S-342-3. At a sub-inhibitory concentration (4 µg/mL), the S-342-3 can effectively reduce the production of polysaccharide intercellular adhesin (PIA) and suppress the initial adhesion of cells in the biofilm. Consistently, the results of RT-qPCR revealed that the expression of genes associated with biofilm formation was downregulated by S-342-3 (P < 0.05). However, we found that treatment with S-342-3 resulted in a significant decrease in the expression of global regulatory genes agrA and sarA (P < 0.05), which play a key role in promoting cell surface attachment and PIA production in S. aureus biofilms. Also importantly, we experimentally proved that the S-342-3 was not toxic to A549 alveolar epithelial cells and the Galleria mellonella larvae. Collectively, these results suggest that the S-342-3 may be a promising anti-biofilm drug candidate with excellent biosafety, which can be further explored for its practical application in health care. IMPORTANCE Biofilms are an important virulence factor in Staphylococcus aureus and are characterized by a structured microbial community consisting of bacterial cells and a secreted extracellular polymeric matrix. Inhibition of biofilm formation is an effective measure to control S. aureus infection. Here, we have synthesized a small molecule compound S-342-3, which exhibits potent inhibition of biofilm formation in both MRSA and MSSA. Further investigations revealed that S-342-3 exerts inhibitory effects on biofilm formation by reducing the production of polysaccharide intercellular adhesin and preventing bacterial adhesion. Our study has confirmed that the inhibitory effect of S-342-3 on biofilm is achieved by downregulating the expression of genes responsible for biofilm formation. In addition, S-342-3 is non-toxic to Galleria mellonella larvae and A549 cells. Consequently, this study demonstrates the efficacy of a biologically safe compound S-342-3 in inhibiting biofilm formation in S. aureus, thereby providing a promising antibiofilm agent for further research.}, } @article {pmid37819110, year = {2023}, author = {Zhang, P and Tang, S and Fu, Q and Luo, Y and Li, J and Chen, Z and Li, H and Ni, G and Wang, T and Chen, G and Liu, X}, title = {Proteomic analysis of anti-MRSA activity of caerin 1.1/1.9 in a murine skin infection model and their in vitro anti-biofilm effects against Acinetobacter baumannii.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0452022}, doi = {10.1128/spectrum.04520-22}, pmid = {37819110}, issn = {2165-0497}, abstract = {Caerin 1 is a family of host defense peptides with antimicrobial properties originally isolated from the Australian tree frog. Both caerin 1.1 and caerin 1.9 have been demonstrated to inhibit infections caused by multiple antibiotic-resistant bacteria, both in vitro and in vivo. In this current study, we conducted a comparison of the minimum inhibitory concentrations of caerin 1.1 and caerin 1.9 (referred to as caerin 1.1/1.9) with commonly used antibiotics against various bacteria, including Staphylococcus aureus, Copper-Green Pseudomonas aeruginosa, Acinetobacter baumannii, and Streptococcus haemolyticus. Our findings reveal that caerin 1.1/1.9 not only prevent the formation of biofilms by A. baumannii but also exhibit a therapeutic effect on established biofilms. Furthermore, our study demonstrates that caerin 1.1/1.9 significantly inhibit the growth of methicillin-resistant Staphylococcus aureus (MRSA) strains in a murine skin infection model. A quantitative proteomic analysis conducted as part of our study indicates that caerin 1.1/1.9 primarily activate oxidative phosphorylation pathways, along with several pathways associated with tissue repair and growth. These findings were observed in comparison to untreated tissues that were infected with MRSA in mice. In summary, our research outcomes suggest that caerin 1.1/1.9 exhibit the potential to serve as promising drug candidates for treating complicated antibiotic-resistant bacterial infections in humans. IMPORTANCE Caerin 1.1 and caerin 1.9, natural antimicrobial peptides derived from tree frogs, have demonstrated the ability to inhibit the growth of antibiotic-resistant bacteria, comparable to certain widely used antibiotics. Additionally, these peptides exhibit the capacity to prevent or treat biofilms formed by bacteria in conjunction with bodily components. The mechanisms underlying their antibacterial effects were investigated through a mouse model of bacterial skin infection, utilizing proteomic analysis as a technological approach.}, } @article {pmid37819084, year = {2023}, author = {Alio, I and Moll, R and Hoffmann, T and Mamat, U and Schaible, UE and Pappenfort, K and Alawi, M and Schie, M and Thünauer, R and Stamm, J and Rohde, H and Streit, WR}, title = {Stenotrophomonas maltophilia affects the gene expression profiles of the major pathogens Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro multispecies biofilm model.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0085923}, doi = {10.1128/spectrum.00859-23}, pmid = {37819084}, issn = {2165-0497}, abstract = {Stenotrophomonas maltophilia is an emerging lung pathogen. In its natural habitat, it lives together with Pseudomonas aeruginosa, Staphylococcus aureus, and other pathogens. Here, we provide the first evidence that S. maltophilia interferes with the metabolism and physiology of other species when co-cultivated in dual- and triple-species biofilms. CSLM analyses implied that S. maltophilia was in general the first to colonize the bottom layer in multispecies biofilms. Structural patterns and niche formation resulting in distinct layer formation within the biofilm were observed on a species- and strain-dependent level for S. maltophilia. Furthermore, gene expression profiles of S. aureus and P. aeruginosa were strongly affected by the presence of S. maltophilia. The S. maltophilia metabolism was mostly fermentative in multispecies biofilms with varying sets of cytochromes used for anaerobic respiration. One of the most striking observations was that S. maltophilia interfered with P. aeruginosa LasI-dependent expression of quorum sensing-regulated pathogenicity factors in multispecies biofilms. IMPORTANCE In the past, studies have focused on bacterial pathogenicity in mono-species infections, in part ignoring the clinical relevance of diseases caused by more than one pathogen (i.e., polymicrobial infections). However, it is now common knowledge that multiple bacteria species are often involved in the course of an infection. For treatment of such infections, it is absolutely important to understand the dynamics of species interactions at possible infection sites and the molecular mechanisms behind these interactions. Here, we studied the impact of Stenotrophomonas maltophilia on its commensals Pseudomonas aeruginosa and Staphylococcus aureus in multispecies biofilms. We analyzed the 3D structural architectures of dual- and triple-species biofilms, niche formation within the biofilms, and the interspecies interactions on a molecular level. RNAseq data identified key genes involved in multispecies biofilm formation and interaction as potential drug targets for the clinical combat of multispecies infection with these major pathogens.}, } @article {pmid37819075, year = {2023}, author = {Pavez, VB and Pacheco, N and Castro-Severyn, J and Pardo-Esté, C and Álvarez, J and Zepeda, P and Krüger, G and Gallardo, K and Melo, F and Vernal, R and Aranda, C and Remonsellez, F and Saavedra, CP}, title = {Characterization of biofilm formation by Exiguobacterium strains in response to arsenic exposure.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0265723}, doi = {10.1128/spectrum.02657-23}, pmid = {37819075}, issn = {2165-0497}, abstract = {The Salar de Huasco (SH) salt lake in northern Chile is an extreme environment characterized by high atmospheric pressure, UV radiation, salinity, variable temperatures, and the presence of heavy metals, including arsenic. Exiguobacterium bacteria have adapted to thrive in these challenging conditions and possess various resistance mechanisms, including biofilm formation, redox reactions, methylation, and altered respiration. In this study, Exiguobacterium strains isolated from the SH were assessed for their capacity to form biofilms in the presence of arsenic, a metalloid that exists in different oxidation states, in order to understand their resistance mechanisms to this heavy metal. The minimum inhibitory concentration (MIC) of each strain against different concentrations of arsenic [III] and [V], biofilm formation using crystal violet staining, and the expression of genes related to biofilm formation were evaluated. The structure of the biofilms was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Furthermore, the extracellular polymeric substances (EPS) produced during biofilm formation were purified, quantified, and their composition determined. The results showed that the tested Exiguobacterium strains exhibit a significant ability to form biofilms when exposed to arsenic. This biofilm contributes to their arsenic resistance, shedding light on the underlying mechanisms. These findings enhanced our understanding of the biofilm formation process, its role in arsenic resistance, and the adaptive strategies employed by bacteria in extreme environments. This study also contributes to the field of microbial resistance mechanisms that have implications for environmental and biotechnological applications. IMPORTANCE In this work, we characterized the composition, structure, and functional potential for biofilm formation of Exiguobacterium strains isolated from the Salar de Huasco in Chile in the presence of arsenic, an abundant metalloid in the Salar that exists in different oxidation states. Our results showed that the Exiguobacterium strains tested exhibit a significant capacity to form biofilms when exposed to arsenic, which would contribute to their resistance to the metalloid. The results highlight the importance of biofilm formation and the presence of specific resistance mechanisms in the ability of microorganisms to survive and thrive under adverse conditions.}, } @article {pmid37817656, year = {2023}, author = {Radhakrishnan, MP and Suryaletha, K and Joseph, I and George, S and Thomas, S}, title = {A Novel Brevinin2 HYba5 Peptide against Polymicrobial Biofilm of Staphylococcus aureus and Enterococcus faecalis.}, journal = {Protein and peptide letters}, volume = {}, number = {}, pages = {}, doi = {10.2174/0109298665266332231001115508}, pmid = {37817656}, issn = {1875-5305}, abstract = {BACKGROUND: Brevinin2 HYba5 (Peptide 29) is a novel cationic peptide identified from an endemic frog, Hydrophylax bahuvistara. Staphylococcus aureus and Enterococcus faecalis are troublesome biofilm-forming pathogens associated with nosocomial and community-acquired infections and contribute to the severity of infections associated with implanted devices and chronic wounds. Co-existence of both pathogens in biofilm mode contributes to an increased antibiotic resistance, treatment failure and hence persistent disease burden. Identifying a novel and stable, less toxic compound targeting multispecies biofilm with a lower probability of acquiring resistance in comparison to antibiotics is highly warranted.

OBJECTIVE: Evaluate the activity of Brevinin2 HYba5 against S. aureus and E. faecalis mixed biofilm.

METHODS: The anti-biofilm activity of peptide 29 was tested by Crystal violet assay, Confocal laser scanning Microscopy (CLSM) and MTT Assay. Cytotoxicity of the peptide was tested in RBC and L929 fibroblast cell line. Biofilm inhibitory activity of the peptide was evaluated at different temperatures, pH, serum and plasma concentrations. The antibiofilm potential of the peptide was tested against polymicrobial biofilm by Fluorescent in situ hybridisation (FISH) and plate counting on HiCromeTM UTI Agar media.

RESULTS: The peptide 29 could inhibit biofilm formation of S. aureus and E. faecalis individually as well as in polymicrobial biofilm at 75 µM concentration. The peptide maintained its antibiofilm potential at different temperatures, serum and plasma concentrations. Activity of the peptide was high at acidic and neutral pH but found to get reduced towards alkaline pH. The peptide is nonhemolytic and does not exhibit significant cytotoxicity against the L929 fibroblast cell line (92.80% cell viability).

CONCLUSION: The biofilm inhibition property makes peptide 29 a promising candidate for the management of S. aureus and E. faecalis biofilm, especially in catheter-associated devices to prevent the initial colonization and thus can ease the burden of pathogenic biofilm-associated infections.}, } @article {pmid37816786, year = {2023}, author = {Yamamoto, K and Tsujimura, Y and Ato, M}, title = {Catheter-associated Mycobacterium intracellulare biofilm infection in C3HeB/FeJ mice.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {17148}, pmid = {37816786}, issn = {2045-2322}, support = {19K16662//MEXT KAKENHI/ ; 2021040169//Takeda Science Foundation/ ; 22fk0108129//Japan Agency for Medical Research and Development/ ; }, abstract = {Non-tuberculosis mycobacterial (NTM) diseases are steadily increasing in prevalence and mortality worldwide. Mycobacterium avium and M. intracellulare, the two major pathogens of NTM diseases, are resistant to antibiotics, and chlorine, necessitating their capacity to survive in natural environments (e.g. soil and rivers) and disinfected municipal water. They can also form biofilms on artificial surfaces to provide a protective barrier and habitat for bacilli, which can cause refractory systemic disseminated NTM disease. Therefore, preventing biofilm formation by these pathogens is crucial; however, not many in vivo experimental systems and studies on NTM biofilm infection are available. This study develops a mouse model of catheter-associated systemic disseminated disease caused by M. intracellulare that reproduces the pathophysiology of catheter-associated infections observed in patients undergoing peritoneal dialysis. In addition, the bioluminescence system enabled noninvasive visualization of the amount and distribution of bacilli in vivo and conveniently examine the efficacy of antimicrobials. Furthermore, the cellulose-based biofilms, which were extensively formed in the tissue surrounding the catheter insertion site, reduced drug therapy effectiveness. Overall, this study provides insights into the cause of the drug resistance of NTM and may guide the development of new therapies for NTM diseases.}, } @article {pmid37816666, year = {2023}, author = {Massey, J and Zarnowski, R and Andes, D}, title = {Role of the Extracellular Matrix in Candida Biofilm Antifungal Resistance.}, journal = {FEMS microbiology reviews}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsre/fuad059}, pmid = {37816666}, issn = {1574-6976}, abstract = {Clinical infection due to Candida species frequently involve growth in biofilm communities. Recalcitrance despite antifungal therapy leads to disease persistence associated with high morbidity and mortality. Candida possesses several tools allowing evasion of antifungal effects. Among these, protection of biofilm cells via encasement by the extracellular matrix is responsible for a majority drug resistance phenotype. The Candida matrix composition is complex and includes a mannan-glucan complex linked to antifungal drug sequestration. This mechanism of resistance is conserved across the Candida genus and impacts each of the available antifungal drug classes. The exosome pathway is responsible for delivery and assembly of much of the Candida extracellular matrix as functional vesicle protein and polysaccharide cargo. Investigations demonstrate the vesicle matrix delivery pathway is a useful fungal biofilm drug target. Further elucidation of the vesicle pathway, as well as understanding the roles of biofilm driven cargo may provide additional targets to aid the diagnosis, prevention, and treatment of Candida biofilms.}, } @article {pmid37816202, year = {2023}, author = {Kumpakha, R and Gordon, DM}, title = {Occidiofungin inhibition of Candida biofilm formation on silicone elastomer surface.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0246023}, doi = {10.1128/spectrum.02460-23}, pmid = {37816202}, issn = {2165-0497}, abstract = {Biofilms are the leading cause of clinically acquired fungal infections and contribute to significantly high morbidity and mortality in immunocompromised and hospitalized patients. Candida biofilms exhibit increased resistance to currently available antifungal agents that contribute to persistent reoccurring infections and are driving efforts to identify novel fungicidal compounds. The natural product, occidiofungin, is an antifungal compound with demonstrated activity against hyphal morphogenesis in polymorphic Candida species. In this study, we use an in vitro static biofilm model to demonstrate the efficacy of occidiofungin against C. albicans and C. tropicalis at all stages of biofilm development, including inhibiting cell dispersal. Consistent with prior findings, we demonstrate that actin organization is altered following occidiofungin exposure to include loss of F-actin cables and accumulation of actin aggregates. Altogether, our results provide strong evidence of the antibiofilm activity of occidiofungin toward Candida biofilms and support its potential as a therapeutic for Candida infections. IMPORTANCE Candida are opportunistic fungal pathogens with medical relevance given their association with superficial to life-threatening infections. An important component of Candida virulence is the ability to form a biofilm. These structures are highly resistant to antifungal therapies and are often the cause of treatment failure. In this work, we evaluated the efficacy of the antifungal compound, occidiofungin, against Candida biofilms developed on a silicone surface. We demonstrate that occidiofungin eliminated cells at all stages of biofilm formation in a dose-dependent manner. Consistent with our understanding of occidiofungin bioactivity, we noted alterations to actin organization and cell morphology following antifungal exposure. Given the challenges associated with the treatment of biofilm-associated infections, occidiofungin exhibits potential as a therapeutic antifungal agent in the future.}, } @article {pmid37815530, year = {2023}, author = {Ruhal, R and Ghosh, M and Kumar, V and Jain, D}, title = {Erratum: Mutation of putative glycosyl transferases PslC and PslI confers susceptibility to antibiotics and leads to drastic reduction in biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {10}, pages = {}, doi = {10.1099/mic.0.001398}, pmid = {37815530}, issn = {1465-2080}, } @article {pmid37815525, year = {2023}, author = {Wiechmann, A and Garcia, V and Elton, L and Williams, P and Atkinson, S}, title = {Reciprocal regulation of NagC and quorum sensing systems and their roles in hmsHFRS expression and biofilm formation in Yersinia pseudotuberculosis.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {10}, pages = {}, doi = {10.1099/mic.0.001397}, pmid = {37815525}, issn = {1465-2080}, } @article {pmid37815454, year = {2023}, author = {Jeon, T and Makabenta, JMV and Park, J and Nabawy, A and Cicek, YA and Mirza, SS and Welton, J and Hassan, MA and Huang, R and Mager, J and Rotello, VM}, title = {Antimicrobial polymer-siRNA polyplexes as a dual-mode platform for the treatment of wound biofilm infections.}, journal = {Materials horizons}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3mh01108a}, pmid = {37815454}, issn = {2051-6355}, abstract = {Treatment of wound biofilm infections faces challenges from both pathogens and uncontrolled host immune response. Treating both issues through a single vector would provide enhanced wound healing. Here, we report the use of a potent cationic antimicrobial polymer to generate siRNA polyplexes for dual-mode treatment of wound biofilms in vivo. These polyplexes act both as an antibiofilm agent and a delivery vehicle for siRNA for the knockdown of biofilm-associated pro-inflammatory MMP9 in host macrophages. The resulting polyplexes were effective in vitro, eradicating MRSA biofilms and efficiently delivering siRNA to macrophages in vitro with concomitant knockdown of MMP9. These polyplexes were likewise effective in an in vivo murine wound biofilm model, significantly reducing bacterial load in the wound (∼99% bacterial clearance) and reducing MMP9 expression by 80% (qRT-PCR). This combination therapeutic strategy dramatically reduced wound purulence and significantly expedited wound healing. Taken together, these polyplexes provide an effective and translatable strategy for managing biofilm-infected wounds.}, } @article {pmid37813281, year = {2023}, author = {Gao, M and Peng, Y and Shen, Y and Tan, F}, title = {Study of the biofilm mechanism of C4-HSL and C6-HSL in the degradation of quinoline.}, journal = {Journal of biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jbiotec.2023.10.002}, pmid = {37813281}, issn = {1873-4863}, abstract = {Quinoline is a hard-to-degrade organic compound widely found in coal chemical wastewater, that seriously affects the ecological environment and human health. A number of biochemical methods are already available for quinoline degradation, but the use of microbial community sensing for quinoline degradation has not been studied in depth. Therefore, this paper focuses on the enhanced mechanism of quorum-sensing signaling molecules in the biofilm formation process during quinoline degradation by functional strains of bacteria. In this paper, the effects of the signal molecules C4-HSL and C6-HSL on the adhesion ability, colony diameter, biofilm formation ability and biofilm morphology of functional strains of quinoline degrading bacteria (Ochrobactrum sp., LC-1) were investigated, and the results showed that both signal molecules promoted the biofilm formation process during the degradation of quinoline by exhibiting an efficient biofortification effect. Both signal molecules could enhance the colony diameter of strain LC-1, where C4-HSL could enhance the biomass of strain LC-1 and stimulate the secretion of extracellular polysaccharides; and C6-HSL could induce the enhancement of adhesion performance and the secretion of extracellular proteins from strain LC-1; both molecules together enhanced the biofilm formation process of strain LC-1. This study has practical application in the degradation of quinoline in coal chemical wastewater.}, } @article {pmid37813217, year = {2023}, author = {Cacioppo, M and De Zorzi, R and Syrgiannis, Z and Bellich, B and Bertoncin, P and Jou, IA and Brady, JW and Rizzo, R and Cescutti, P}, title = {Microscopy and modelling investigations on the morphology of the biofilm exopolysaccharide produced by Burkholderia multivorans strain C1576.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127294}, doi = {10.1016/j.ijbiomac.2023.127294}, pmid = {37813217}, issn = {1879-0003}, abstract = {Bacteria form very often biofilms where they embed in a self-synthesized matrix exhibiting a gel-like appearance. Matrices offer several advantages, including defence against external threats and the easiness of intercellular communication. In infections, biofilm formation enhances bacteria resistance against antimicrobials, causing serious clinical problems for patients' treatments. Biofilm matrices are composed of proteins, extracellular DNA, and polysaccharides, the latter being the major responsible for matrix architecture. The repeating unit of the biofilm polysaccharide synthesized by Burkholderia multivorans strain C1576 contains two mannoses and two sequentially linked rhamnoses, one of them 50 % methylated on C-3. Rhamnose, a 6-deoxysugar, has lower polarity than other common monosaccharides and its methylation further reduces polarity. This suggests a possible role of this polysaccharide in the biofilm matrix; in fact, computer modelling and atomic force microscopy studies evidenced intra- and inter-molecular non-polar interactions both within polysaccharides and with aliphatic molecules. In this paper, the polysaccharide three-dimensional morphology was investigated using atomic force microscopy in both solid and solution states. Independent evidence of the polymer conformation was obtained by transmission electron microscopy which confirmed the formation of globular compact structures. Finally, data from computer dynamic simulations were used to model the three-dimensional structure.}, } @article {pmid37812897, year = {2023}, author = {Dong, Y and Zhang, J and Wang, Q and Xu, D and Pang, S and Campos, LC and Ren, Z and Wang, P}, title = {Dual function of magnetic field in enhancing antibiotic wastewater treatment by an integrated photocatalysis and fluidized bed biofilm reactor (FBBR).}, journal = {Journal of environmental management}, volume = {347}, number = {}, pages = {119249}, doi = {10.1016/j.jenvman.2023.119249}, pmid = {37812897}, issn = {1095-8630}, abstract = {The integrated photocatalysis and fluidized bed biofilm reactor (FBBR) is an attractive wastewater treatment technique for managing wastewater containing antibiotics. However, the fast recombination of photoinduced charge and low microbial activity limit the degradation and mineralization efficiency for antibiotics. To address this, we attempt to introduce magnetic field (MF) to the integrated system with B-doped Bi3O4Cl as the photocatalysts to effectively improve removal and mineralization of ciprofloxacin (CIP). As a consequence, the degradation rate reaches 96% after 40 d in integrated system with MF. The biofilm inside the integrated system with MF carrier can mineralize the photocatalytic products, thereby increasing the total organic carbon (TOC) degradation rate by more than 32%. The electrochemical experiment indicates the Lorentz force generated by MF can accelerate charge separation, increasing the electron concentration. Simultaneously, the increased amounts of electrons lead to the generation of more ·OH and ·O2[-]. MF addition also results in increased biomass, increased biological respiratory activity, microbial community evolution and accelerated microbial metabolism, enabling more members to biodegrade photocatalytic intermediates. Therefore, applied MF is an efficient method to enhance CIP degradation and mineralization by the integrated system.}, } @article {pmid37812886, year = {2023}, author = {Yap, CH and Ramle, AQ and Lim, SK and Rames, A and Tay, ST and Chin, SP and Kiew, LV and Tiekink, ERT and Chee, CF}, title = {Synthesis and Staphylococcus aureus biofilm inhibitory activity of indolenine-substituted pyrazole and pyrimido[1,2-b]indazole derivatives.}, journal = {Bioorganic & medicinal chemistry}, volume = {95}, number = {}, pages = {117485}, doi = {10.1016/j.bmc.2023.117485}, pmid = {37812886}, issn = {1464-3391}, abstract = {Staphylococcus aureus is a highly adaptable opportunistic pathogen that can form biofilms and generate persister cells, leading to life-threatening infections that are difficult to treat with antibiotics alone. Therefore, there is a need for an effective S. aureus biofilm inhibitor to combat this public health threat. In this study, a small library of indolenine-substituted pyrazoles and pyrimido[1,2-b]indazole derivatives were synthesised, of which the hit compound exhibited promising antibiofilm activities against methicillin-susceptible S. aureus (MSSA ATCC 29213) and methicillin-resistant S. aureus (MRSA ATCC 33591) at concentrations significantly lower than the planktonic growth inhibition. The hit compound could prevent biofilm formation and eradicate mature biofilms of MSSA and MRSA, with a minimum biofilm inhibitory concentration (MBIC50) value as low as 1.56 µg/mL and a minimum biofilm eradication concentration (MBEC50) value as low as 6.25 µg/mL. The minimum inhibitory concentration (MIC) values of the hit compound against MSSA and MRSA were 50 µg/mL and 25 µg/mL, respectively, while the minimum bactericidal concentration (MBC) values against MSSA and MRSA were > 100 µg/mL. Preliminary structure-activity relationship analysis reveals that the fused benzene ring and COOH group of the hit compound are crucial for the antibiofilm activity. Additionally, the compound was not cytotoxic to human alveolar A549 cells, thus highlighting its potential as a suitable candidate for further development as a S. aureus biofilm inhibitor.}, } @article {pmid37812192, year = {2023}, author = {Bratkic, A and Jazbec, A and Toplak, N and Koren, S and Lojen, S and Tinta, T and Kostanjsek, R and Snoj, L}, title = {The Colonization of an Irradiated Environment: The Case of Microbial Biofilm in a Nuclear Reactor.}, journal = {International journal of radiation biology}, volume = {}, number = {}, pages = {1-30}, doi = {10.1080/09553002.2023.2258206}, pmid = {37812192}, issn = {1362-3095}, } @article {pmid37812003, year = {2023}, author = {Coenye, T}, title = {Biofilm antimicrobial susceptibility testing: where are we and where could we be going?.}, journal = {Clinical microbiology reviews}, volume = {}, number = {}, pages = {e0002423}, doi = {10.1128/cmr.00024-23}, pmid = {37812003}, issn = {1098-6618}, abstract = {SUMMARYOur knowledge about the fundamental aspects of biofilm biology, including the mechanisms behind the reduced antimicrobial susceptibility of biofilms, has increased drastically over the last decades. However, this knowledge has so far not been translated into major changes in clinical practice. While the biofilm concept is increasingly on the radar of clinical microbiologists, physicians, and healthcare professionals in general, the standardized tools to study biofilms in the clinical microbiology laboratory are still lacking; one area in which this is particularly obvious is that of antimicrobial susceptibility testing (AST). It is generally accepted that the biofilm lifestyle has a tremendous impact on antibiotic susceptibility, yet AST is typically still carried out with planktonic cells. On top of that, the microenvironment at the site of infection is an important driver for microbial physiology and hence susceptibility; but this is poorly reflected in current AST methods. The goal of this review is to provide an overview of the state of the art concerning biofilm AST and highlight the knowledge gaps in this area. Subsequently, potential ways to improve biofilm-based AST will be discussed. Finally, bottlenecks currently preventing the use of biofilm AST in clinical practice, as well as the steps needed to get past these bottlenecks, will be discussed.}, } @article {pmid37811587, year = {2023}, author = {Oliveira, IM and Gomes, IB and Plácido, A and Simões, LC and Eaton, P and Simões, M}, title = {The impact of potassium peroxymonosulphate and chlorinated cyanurates on biofilms of Stenotrophomonas maltophilia: effects on biofilm control, regrowth, and mechanical properties.}, journal = {Biofouling}, volume = {39}, number = {7}, pages = {691-705}, doi = {10.1080/08927014.2023.2254704}, pmid = {37811587}, issn = {1029-2454}, abstract = {The activity of two chlorinated isocyanurates (NaDCC and TCCA) and peroxymonosulphate (OXONE) was evaluated against biofilms of Stenotrophomonas maltophilia, an emerging pathogen isolated from drinking water (DW), and for the prevention of biofilm regrowth. After disinfection of pre-formed 48 h-old biofilms, the culturability was reduced up to 7 log, with OXONE, TCCA, and NaDCC showing more efficiency than free chlorine against biofilms formed on stainless steel. The regrowth of biofilms previously exposed to OXONE was reduced by 5 and 4 log CFU cm[-2] in comparison to the unexposed biofilms and biofilms exposed to free chlorine, respectively. Rheometry analysis showed that biofilms presented properties of viscoelastic solid materials, regardless of the treatment. OXONE reduced the cohesiveness of the biofilm, given the significant decrease in the complex shear modulus (G*). AFM analysis revealed that biofilms had a fractured appearance and smaller bacterial aggregates dispersed throughout the surface after OXONE exposure than the control sample. In general, OXONE has been demonstrated to be a promising disinfectant to control DW biofilms, with a higher activity than chlorine. The results also show the impact of the biofilm mechanical properties on the efficacy of the disinfectants in biofilm control.}, } @article {pmid37809422, year = {2023}, author = {Milton, AAP and Srinivas, K and Lyngdoh, V and Momin, AG and Lapang, N and Priya, GB and Ghatak, S and Sanjukta, RK and Sen, A and Das, S}, title = {Biofilm-forming antimicrobial-resistant pathogenic Escherichia coli: A one health challenge in Northeast India.}, journal = {Heliyon}, volume = {9}, number = {9}, pages = {e20059}, pmid = {37809422}, issn = {2405-8440}, abstract = {This study aimed to investigate the prevalence of Shiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) in common food animals (cattle, goats, and pigs) reared by tribal communities and smallholder farmers in Northeast India. The isolates were characterized for the presence of virulence genes, extended-spectrum beta-lactamases (ESBL) production, antimicrobial resistance, and biofilm production, and the results were statistically interpreted. In pathotyping 141 E. coli isolates, 10 (7.09%, 95% CI: 3.45%-12.66%) were identified as STEC, 2 (1.42%, 95% CI: 0.17%-5.03%) as atypical-EPEC, and 1 (0.71%, 95% CI: 0.02%-3.89%) as typical-EPEC. None of the isolates were classified as ETEC. Additionally, using the phenotypic combination disc method (ceftazidime with and without clavulanic acid), six isolates (46.1%, 95% CI: 19.22%-74.87%) were determined to be ESBL producers. Among the STEC/EPEC strains, eleven (84.6%, 95% CI: 54.55%-98.08%) and one (7.7%, 95% CI: 0.19%-36.03%) strains were capable of producing strong or moderate biofilms, respectively. PFGE analysis revealed indistinguishable patterns for certain isolates, suggesting clonal relationships. These findings highlight the potential role of food animals reared by tribal communities and smallholder farmers as reservoirs of virulent biofilm-forming E. coli pathotypes, with implications for food contamination and zoonotic infections. Therefore, monitoring these pathogens in food animals is crucial for optimizing public health through one health strategy.}, } @article {pmid37808288, year = {2023}, author = {Gong, XX and Zeng, YH and Chen, HM and Zhang, N and Han, Y and Long, H and Xie, ZY}, title = {Bioinformatic and functional characterization of cyclic-di-GMP metabolic proteins in Vibrio alginolyticus unveils key diguanylate cyclases controlling multiple biofilm-associated phenotypes.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1258415}, pmid = {37808288}, issn = {1664-302X}, abstract = {The biofilm lifestyle is critical for bacterial survival and proliferation in the fluctuating marine environment. Cyclic diguanylate (c-di-GMP) is a key second messenger during bacterial adaptation to various environmental signals, which has been identified as a master regulator of biofilm formation. However, little is known about whether and how c-di-GMP signaling regulates biofilm formation in Vibrio alginolyticus, a globally dominant marine pathogen. Here, a large set of 63 proteins were predicted to participate in c-di-GMP metabolism (biosynthesis or degradation) in a pathogenic V. alginolyticus strain HN08155. Guided by protein homology, conserved domains and gene context information, a representative subset of 22 c-di-GMP metabolic proteins were selected to determine which ones affect biofilm-associated phenotypes. By comparing phenotypic differences between the wild-type and mutants or overexpression strains, we found that 22 c-di-GMP metabolic proteins can separately regulate different phenotypic outputs in V. alginolyticus. The results indicated that overexpression of four c-di-GMP metabolic proteins, including VA0356, VA1591 (CdgM), VA4033 (DgcB) and VA0088, strongly enhanced rugose colony morphotypes and strengthened Congo Red (CR) binding capacity, both of which are indicators of biofilm matrix overproduction. Furthermore, rugose enhanced colonies were accompanied by increased transcript levels of extracellular polysaccharide (EPS) biosynthesis genes and decreased expression of flagellar synthesis genes compared to smooth colonies (WTpBAD control), as demonstrated by overexpression strains WTp4033 and ∆VA4033p4033. Overall, the high abundance of c-di-GMP metabolic proteins in V. alginolyticus suggests that c-di-GMP signaling and regulatory system could play a key role in its response and adaptation to the ever-changing marine environment. This work provides a robust foundation for the study of the molecular mechanisms of c-di-GMP in the biofilm formation of V. alginolyticus.}, } @article {pmid37807974, year = {2023}, author = {Peng, Q and Tang, X and Dong, W and Zhi, Z and Zhong, T and Lin, S and Ye, J and Qian, X and Chen, F and Yuan, W}, title = {Carvacrol inhibits bacterial polysaccharide intracellular adhesin synthesis and biofilm formation of mucoid Staphylococcus aureus: an in vitro and in vivo study.}, journal = {RSC advances}, volume = {13}, number = {41}, pages = {28743-28752}, pmid = {37807974}, issn = {2046-2069}, abstract = {Staphylococcus aureus (S. aureus) is one of the important human pathogens and causes both superficial and systemic infections. More importantly, the formation of S. aureus biofilms, a main cause of its pathogenicity and drug resistance, has been a critical challenge in clinical treatment. Carvacrol, a plant-based natural product, has gained great interest for therapeutic purposes due to its effective biological activity with low cytotoxicity. The present study aimed to investigate the effect of carvacrol on anti-biofilm activity. Growth curve analysis showed that applying a sub-inhibitory concentration of carvacrol (4 μg mL[-1]) was not lethal to S. aureus SYN; however, the inhibition rate of biofilm formation was as high as 63.6%, and the clearance rate of mature biofilms was as high as 30.7%. In addition, carvacrol effectively reduced the production of biofilm-associated extracellular polysaccharides and showed no effect on eDNA release. Furthermore, qPCR analysis revealed that carvacrol significantly down-regulated the expression of icaA, icaB, icaC, agrA, and sarA (P < 0.05). The in vivo efficacy of carvacrol against biofilm infection was further verified with a biological model of G. mellonella larvae. The results showed that carvacrol was non-toxic to the larvae and can effectively increase the survival rate of the larvae infected with S. aureus strain SYN.}, } @article {pmid37807898, year = {2023}, author = {Li, C and Miao, L and Adyel, TM and Wu, J and Hou, J}, title = {Transformation of Biofilm to Carbon Sinks after Prolonged Droughts Linked with Algal Biodiversity Change.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c04631}, pmid = {37807898}, issn = {1520-5851}, abstract = {Global climate change significantly increased the duration of droughts in intermittent rivers, impacting benthic microbial-mediated biogeochemical processes. However, the impact of prolonged droughts on the carbon contribution of intermittent rivers remains poorly understood. In this study, we investigated the potential effects of varying drought gradients (ranging from 20 to 130 days) on benthic biofilms community structure (algae, bacteria, and fungi) and their carbon metabolism functions (ecosystem metabolism and carbon dioxide (CO2) emission fluxes) using mesocosm experiments. Our findings indicate that longer drought durations lead to reduced alpha diversity and community heterogeneity, tighter interdomain networks, and an increased role of stochastic processes in community assembly, with a discernible threshold at around 60 days. Concurrently, the biofilm transforms into a carbon sink following a drought period of 60 days, as evidenced by the transformation of CO2 emission fluxes from 633.25 ± 194.69 to -349.61 ± 277.79 mg m[-2] h[-1]. Additionally, the partial least-squares path model revealed that the resilience of algal communities and network stability may drive biofilm's transformation into a carbon sink, primarily through the heightened resilience of autotrophic metabolism. This study underscores the significance of the carbon contribution from intermittent rivers, as the shift in carbon metabolism functions with increasing droughts could lead to skewed estimations of current riverine carbon fluxes.}, } @article {pmid37806331, year = {2023}, author = {Li, J and Liu, H and Zhao, C and Zhang, J and He, W}, title = {Autoinducer-2 quorum sensing regulates biofilm formation and chain elongation metabolic pathways to enhance caproate synthesis in microbial electrochemical system.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140384}, doi = {10.1016/j.chemosphere.2023.140384}, pmid = {37806331}, issn = {1879-1298}, abstract = {Quorum sensing (QS) have been explored extensively. However, most studies focused on N-acyl homoserine lactones (AHLs) participating in intraspecies QS. In this study, autoinducer-2 (AI-2, participating in interspecies QS) with different concentration was investigated for chain elongation in microbial electrosynthesis (MES). The results demonstrated that the R3 treatment, which involved adding 10 μM of 4,5-dihydroxy-2,3-pentanedione (DPD) in the reactor, exhibited the best performance. The concentration of caproate was increased by 66.88% and the redox activity of cathodic electroactive biofilms (EABs) was enhanced. Meanwhile, microbial community data indicated that Negativicutes relative abundance was increased obviously in R3 treatment. In this study, the transcriptome Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases were used to analyze the metabolic pathway of chain elongation involving fatty acid biosynthesis (FAB) pathway and reverse β-oxidization (RBO) pathway. KEGG analysis revealed that fatty acid elongation metabolism (p < 0.001), tryptophan metabolism (p < 0.01), arginine and proline metabolism (p < 0.05) were significantly improved in R3 treatment. GO analysis suggested that R3 treatment mainly upregulated significantly transmembrane signaling receptor activity (p < 0.01), oxidoreductase activity (p < 0.05), and phosphorelay signal transduction (p < 0.05). Moreover, metatranscriptomic analyses also showed that R3 treatment could upregulate the LuxP extracellular receptor, LuxO transcriptional activator, LsrB periplasmic protein, and were beneficial to both FAB and RBO pathways. These findings provided a new insight into chain elongation in MES system.}, } @article {pmid37806259, year = {2023}, author = {Cui, Y and Gao, J and Zeng, L and Guo, Y and Xu, H and Zhao, M}, title = {Different fates of extracellular and intracellular antibiotic resistance genes in flocs, granular and biofilm nitrification systems under the stress of acetaminophen.}, journal = {Journal of hazardous materials}, volume = {461}, number = {}, pages = {132675}, doi = {10.1016/j.jhazmat.2023.132675}, pmid = {37806259}, issn = {1873-3336}, abstract = {The spread of antibiotic resistance genes (ARGs), including intracellular ARGs (i-ARGs) and extracellular ARGs (e-ARGs), has become a global problem that cannot be ignored. This study clarified the fates of e-ARGs and i-ARGs in floc sludge reactor (FS), granular sludge reactor (GS) and biofilm reactor (BF) under the stress of acetaminophen (APAP). The results showed that the risk of ARGs transmission, especially for e-ARGs, in FS and BF could increase with the increasing times of APAP treatment, except for that in GS. The fates of i-ARGs in three different systems were similar, which were mainly clustered as the efflux pumps mechanism. The secretion and disintegration of extracellular polymeric substances mainly affected the fates of e-ARGs. In the three systems, the complexity of network relationships between ARGs and microbial communities was FS, GS and BF. Partial least-squares path model analysis indicated that bacterial community directly contributed to the variations of e-ARGs and i-ARGs under APAP treatment in the three systems, playing a leading role. And i-ARGs and protein secondary structure showed direct effects on e-ARGs. This study indicated that e-ARGs in complex systems were more susceptible to be influenced, which should be paid more attention to prevent further propagation of ARGs.}, } @article {pmid37805972, year = {2023}, author = {Pandit, B and Moin, A and Mondal, A and Banik, A and Alam, M}, title = {Characterization of a biofilm-forming, amylase-producing, and heavy-metal-bioremediating strain Micrococcus sp. BirBP01 isolated from oligotrophic subsurface lateritic soil.}, journal = {Archives of microbiology}, volume = {205}, number = {11}, pages = {351}, pmid = {37805972}, issn = {1432-072X}, abstract = {Lateritic soil is the reddish to brown-colored soil composed mainly of iron or aluminium oxides, hydroxides, or oxyhydroxides. Information on bacteria that inhabit this soil type, their ecological role, and metabolic potential are scarce. We have isolated and partially characterized a bacterial strain BirBP01 from a lead, calcium, and magnesium-rich, oligotrophic subsurface lateritic soil-sample collected from 12-feet deep horizon of a laterite mining pit in Birbhum district, India. The isolate is a biofilm-forming, Gram-positive bacterium having a sarcinae arrangement, mesophilic, slightly alkaliphilic, able to produce amylase, and resistant against multiple heavy-metals. BirBP01 has the ability to bioremediate 51% of Pb, 30% of Zn, and 22% of Cu through biosorption, possibly into the biofilm matrix. The bioremediating ability of the bacterium alleviated the inhibitory effect of heavy-metals on the germination of chickpea (Cicer arietinum L.) seeds. 16S rRNA gene-based phylogenetic analysis revealed that BirBP01 is a member of the genus Micrococcus. It showed more than 99% identity of the 16S rRNA gene sequence, and clustered within the same branch of the phylogenetic tree, with strains of M. yunnanensis, M. endophyticus, and M. luteus. The ability to produce amylase, and bioremediate heavy-metals signify that Micrococcus sp. BirBP01 could be potentially a good candidate for industrial applications, and to clean up heavy-metal contaminated sites.}, } @article {pmid37804971, year = {2023}, author = {Zhao, M and Gao, J and Cui, Y and Zhang, H and Wang, Z and Zhang, S and Sun, L}, title = {The effects of didodecyl dimethyl ammonium chloride on microbial communities and resistance genes in floc, granular and biofilm denitrification sludge.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167618}, doi = {10.1016/j.scitotenv.2023.167618}, pmid = {37804971}, issn = {1879-1026}, abstract = {As a type of quaternary ammonium compounds, didodecyl dimethyl ammonium chloride (DADMAC C12) was frequently detected in wastewater treatment plants. Here, floc-based sequencing batch reactor (FSBR), granule-based SBR (GSBR) and biofilm SBR (BSBR) were fed with 0.5, 5 and 10 mg/L of DADMAC C12 for 120 d. Compared with floc sludge and granule sludge, biofilm had the strongest ability to resist the impact of DADMAC C12. Notably, in both FSBR and GSBR systems, 5 mg/L DADMAC C12 promoted denitrification sludge to become hydrophobic and compact due to an increase in α-Helix/(β-Sheet+Random coil), consequently enhancing sludge granulation. Besides，high concentration of DADMAC C12 generally increased the abundances of MGEs in three denitrification systems, except extracellular MGEs in water. The variation of efflux pump ARGs was basically consistent with that of MGEs. The stimulation of DADMAC C12 also increased significantly the abundance of extracellular antibiotics deactivation ARGs in water in three denitrification systems. Besides, DADMAC C12 induced co-selection among various ARGs and promoted the proliferation and spread of sulfonamide ARGs in water.}, } @article {pmid37804964, year = {2023}, author = {Tong, CY and Honda, K and Derek, CJC}, title = {Enhancing organic matter productivity in microalgal-bacterial biofilm using novel bio-coating.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167576}, doi = {10.1016/j.scitotenv.2023.167576}, pmid = {37804964}, issn = {1879-1026}, abstract = {Research on renewable energy from microalgae has led to a growing interest in porous substrate photobioreactors, but their widespread adoption is currently limited to pure microalgal biofilm cultures. The behavior of microalgal-bacterial biofilms immobilized on microporous substrates remains as a research challenge, particularly in uncovering their mutualistic interactions in environment enriched with dissolved organic matter. Therefore, this study established a novel culture platform by introducing microalgal-derived bio-coating that preconditioned hydrophilic polyvinylidene fluoride membranes for the microalgal-bacterial biofilm growth of freshwater microalgae, Chlorella vulgaris ESP 31 and marine microalgae, Cylindrotheca fusiformis with bacteria, Escherichia coli. In the attached co-culture mode, the bio-coating we proposed demonstrated the ability to enhance microalgal growth for both studied species by a range of 2.5 % to 19 % starting from day 10 onwards. Additionally, when compared to co-culture on uncoated membranes, the bio-coating exhibited a significant bacterial growth promotion effect, increasing bacterial growth by at least 2.35 times for the C. vulgaris-E. coli co-culture after an initial adaptation phase. A significant increase of at least 72 % in intracellular biochemical compounds (including chlorophyll, polysaccharides, proteins, and lipids) was observed within just five days, primarily due to the high concentration of pre-coated organic matter, mainly sourced from the internal organic matter (IOM) of C. fusiformis. Higher accumulation of organic compounds in the bio-coating indirectly triggers a competition between microalgae and bacteria which potentially stimulate the production of additional intra-/extra-organic substances as a defensive response. In short, insight gained from this study may represent a paradigm shift in the ways that symbiotic interactions are promoted to increase the yield of specific bio-compounds with the presence of bio-coating.}, } @article {pmid37804893, year = {2023}, author = {Karyani, TZ and Ghattavi, S and Homaei, A}, title = {Application of enzymes for targeted removal of biofilm and fouling from fouling-release surfaces in marine environments: A review.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127269}, doi = {10.1016/j.ijbiomac.2023.127269}, pmid = {37804893}, issn = {1879-0003}, abstract = {Biofouling causes adverse issues in underwater structures including ship hulls, aquaculture cages, fishnets, petroleum pipelines, sensors, and other equipment. Marine constructions and vessels frequently are using coatings with antifouling properties. During the previous ten years, several alternative strategies have been used to combat the biofilm and biofouling that have developed on different abiotic or biotic surfaces. Enzymes have frequently been suggested as a cost-effective, substitute, eco-friendly, for conventional antifouling and antibiofilm substances. The destruction of sticky biopolymers, biofilm matrix disorder, bacterial signal interference, and the creation of biocide or inhibitors are among the catalytic reactions of enzymes that really can successfully prevent the formation of biofilms. In this review we presented enzymes that have antifouling and antibiofilm properties in the marine environment like α-amylase, protease, lysozymes, glycoside hydrolase, aminopeptidases, oxidase, haloperoxidase and lipases. We also overviewed the function, benefits and challenges of enzymes in removing biofouling. The reports suggest enzymes are good candidates for marine environment. According to the findings of a review of studies in this field, none of the enzymes were able to inhibit the development of biofilm by a site marine microbial community when used alone and we suggest using other enzymes or a mixture of enzymes for antifouling and antibiofilm purposes in the sea environment.}, } @article {pmid37804807, year = {2023}, author = {Xue, YM and Wang, YC and Lin, YT and Jiang, GY and Chen, R and Qin, RL and Jia, XQ and Wang, C}, title = {Engineering a Pseudomonas putida as living quorum quencher for biofilm formation inhibition, benzenes degradation, and environmental risk evaluation.}, journal = {Water research}, volume = {246}, number = {}, pages = {120690}, doi = {10.1016/j.watres.2023.120690}, pmid = {37804807}, issn = {1879-2448}, abstract = {Bacterial communication interruption based on quorum quenching (QQ) has been proven its potential in biofilm formation inhibition and biofouling control. However, it would be more satisfying if QQ could be combined with the efficient degradation of contaminants in environmental engineering. In this study, we engineered a biofilm of Pseudomonas putida through introducing a QQ synthetic gene, which achieved both biofilm formation inhibition and efficient degradation of benzene series in wastewater. The aiiO gene introduced into the P. putida by heat shock method was highly expressed to produce QQ enzyme to degrade AHL-based signal molecules. The addition of this engineered P. putida reduced the AHLs concentration, quorum sensing gene expression, and connections of the microbial community network in activated sludge and therefore inhibited the biofilm formation. Meanwhile, the sodium benzoate degradation assay indicated an enhanced benzene series removal ability of the engineering bacteria on activated sludge. Besides, we also demonstrated a controllable environmental risk of this engineered bacteria through monitoring its abundance and horizontal gene transfer test. Overall, the results of this study suggest an alternative strategy to solve multiple environmental problems through genetic engineering means and provide support for the application of engineered bacteria in environmental biotechnology.}, } @article {pmid37803782, year = {2023}, author = {Song, D and Jia, A and Qi, X and Dong, K and Liu, S and Man, C and Yang, X and Jiang, Y}, title = {Co-culture of Cronobacter sakazakii and Staphylococcus aureus: Explore the influence of mixed biofilm formation and regulation of Cronobacter sakazakii biofilm formation genes.}, journal = {Food research international (Ottawa, Ont.)}, volume = {173}, number = {Pt 2}, pages = {113457}, doi = {10.1016/j.foodres.2023.113457}, pmid = {37803782}, issn = {1873-7145}, abstract = {Bacterial biofilm is a protective matrix composed of metabolites secreted by bacteria that envelop bacteria. By forming a biofilm, bacteria can considerably improve their environmental tolerance. In food-related processing environment, different types of microorganisms are often present in biofilms. The main contaminating strain in the powdered infant formula (PIF) processing environment, Cronobacter sakazakii and Staphylococcus aureus continues to pollute the PIF processing environment after biofilm production. This study selected Cronobacter sakazakii with a weak biofilm-forming ability as one of the test organisms. The coexistence of Cronobacter sakazakii and Staphylococcus aureus on the surface of production equipment was simulated to analyze the interaction. Biofilm formation in the co-culture group was significantly higher than the others. In-depth study of the effect of Staphylococcus aureus on the biofilm formation genes of Cronobacter sakazakii. Results show two bacteria can coexist on the surface of a metal device, forming a more compact hybrid biofilm structure. Under co-culture conditions, S. aureus increased bcsA and fliD expression in Cronobacter sakazakii, whereas decreased bcsC expression. Signaling molecules produced by Staphylococcus aureus (Autoinducer 2) significantly promoted the biofilm formation of Cronobacter sakazakii at the concentration of 0-500 ng/mL (0.099-0.177) and up-regulated the expression of bcsA, filD and flhD genes.}, } @article {pmid37803439, year = {2023}, author = {Li, B and Mao, J and Wu, J and Mao, K and Jia, Y and Chen, F and Liu, J}, title = {Nano-Bio Interactions: Biofilm-Targeted Antibacterial Nanomaterials.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2306135}, doi = {10.1002/smll.202306135}, pmid = {37803439}, issn = {1613-6829}, support = {32171398//National Natural Science Foundation of China/ ; L212015//Beijing Natural Science Foundation/ ; YSBR-036//CAS Project for Young Scientists in Basic Research/ ; 2022013//Beijing Nova Program/ ; E1985111ZX//Hundred-Talent Program of Chinese Academy of Sciences/ ; }, abstract = {Biofilm is a spatially organized community formed by the accumulation of both microorganisms and their secretions, leading to persistent and chronic infections because of high resistance toward conventional antibiotics. In view of the tunable physicochemical properties and the related unique biological behavior (e.g., size-, shape-, and surface charge-dependent penetration, protein corona endowed targeting, catalytic- and electronic-related oxidative stress, optical- and magnetic-associated hyperthermia, etc.), nanomaterials-based therapeutics are widely used for the treatment of biofilm-associated infections. In this review, the biological characteristics of biofilm are introduced. And the nanomaterials-based antibacterial strategies are further discussed via biofilm targeting, including preventing biofilm formation, enhancing biofilm penetration, disrupting the mature biofilm, and acting as drug delivery systems. In which, the interactions between biofilm and nanomaterials include mechanical disruption, electron transfer, enzymatic degradation, oxidative stress, and hyperthermia. Additionally, the current advances of nanomaterials for antibacterial nanomaterials by biofilm targeting are summarized. This review aims to present a complete vision of antibacterial nanomaterials-biofilm (nano-bio) interactions, paving the way for the future development and clinical translation of effective antibacterial nanomedicines.}, } @article {pmid37802452, year = {2023}, author = {Lin, X and Fu, T and Lei, Y and Xua, J and Wang, S and He, F and Xie, Z and Zhang, L}, title = {An injectable and light curable hyaluronic acid composite gel with anti-biofilm, anti-inflammatory and pro-healing characteristics for accelerating infected wound healing.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127190}, doi = {10.1016/j.ijbiomac.2023.127190}, pmid = {37802452}, issn = {1879-0003}, abstract = {Bacterial biofilm formation and drug resistance are common issues associated with wound healing. Antimicrobial peptides (AMPs) are a new class of antimicrobial agents with the potential to solve these global health issues. New injectable adhesive antibacterial hydrogels have excellent prospects of becoming the next innovative wound-healing dressings. In this study, the hyaluronic acid was connected to the antibacterial peptide Plantaricin 149 (Pln149), obtaining HAD@AMP. HAD@AMP performed well in efficient antimicrobial activity, good histocompatibility, low drug resistance, low bacterial biofilm formation, and fast wound healing process which are essential for rapid healing of infected wound. During the hydrogel degradation process, Pln149 was released to inhibit bacterial communication and reduce bacterial biofilm formation. Meanwhile, HAD@AMP could up-regulate anti-inflammatory and pro-angiogenic factors, and down-regulate inflammatory factors to promote the healing of infected wounds, which provide a new idea for skin healing strategies.}, } @article {pmid37802451, year = {2023}, author = {Dehari, D and Kumar, DN and Chaudhuri, A and Kumar, A and Kumar, R and Kumar, D and Singh, S and Nath, G and Agrawal, AK}, title = {Bacteriophage entrapped chitosan microgel for biofilm-mediated poly bacterial infection in burn wounds.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127247}, doi = {10.1016/j.ijbiomac.2023.127247}, pmid = {37802451}, issn = {1879-0003}, abstract = {Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria are most commonly present in burn wound infections. Multidrug resistance (MDR) and biofilm formation make it difficult to treat these infections. Bacteriophages (BPs) are proven as an effective therapy against MDR as well as biofilm-associated wound infections. In the present work, a naturally inspired bacteriophage cocktail loaded chitosan microparticles-laden topical gel is developed for the effective treatment of these infections. Bacteriophages against MDR S. aureus (BPSAФ1) and P. aeruginosa (BPPAФ1) were isolated and loaded separately and in combination into the chitosan microparticles (BPSAФ1-CHMPs, BPPAФ1-CHMPs, and MBP-CHMPs), which were later incorporated into the SEPINEO™ P 600 gel (BPSAФ1-CHMPs-gel, BPPAФ1-CHMPs-gel, and MBP-CHMPs-gel). BPs were characterized for their morphology, lytic activity, burst size, and hemocompatibility, and found to be in Caudoviricetes class. Furthermore, BPSAФ1-CHMPs, BPPAФ1-CHMPs, and MBP-CHMPs had an average particle size of 1.19 ± 0.11, 1.42 ± 0.21, and 2.84 ± 0.28 μm, respectively, and expressed in vitro antibiofilm eradication potency. The ultrasound and photoacoustic imaging in infected burn wounds demonstrated improved wound healing reduced inflammation and increased oxygen saturation. The obtained results suggested that the incorporation of the BPs in the MP-gel protected the BPs, sustained the BPs release, and improved the antibacterial activity.}, } @article {pmid37801273, year = {2023}, author = {Liu, J and Ding, Y and Yu, X and Ye, S and Guo, P and Yang, B}, title = {Fabric Fiber as a Biofilm Carrier for Halomonas sp. H09 Mixed with Lactobacillus rhamnosus GG.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37801273}, issn = {1559-0291}, support = {32171836//National Natural Science Foundation of China/ ; LJKZ0528,2020-MZLH-37//Natural Science Foundation of Liaoning Province/ ; }, abstract = {Biofilm bacteria have stronger resistance to the adverse external environment compared to planktonic bacteria, and biofilms of non-pathogenic bacteria have strong potential for applications in food. In this experiment, Halomonas sp. H09 and Lactobacillus rhamnosus GG, which have film-forming ability in monoculture and better film-forming ability in mixed culture than the two strains alone, were selected as the target strains for mixed culture. According to SEM observation and bacterial dry weight measurement, the target strain formed a dense biofilm on a 0.1 g/L chitosan-modified cellulose III carrier. Furthermore, the presence of extracellular polymeric substances in biofilms was verified by EDS and FTIR. The results showed that 0.1 g/L chitosan-modified cellulose III was an ideal carrier material for immobilization of Halomonas sp. H09 with Lactobacillus rhamnosus GG biofilm. This research provided a basis for the selection of non-pathogenic mixed-bacteria biofilm carriers.}, } @article {pmid37800624, year = {2023}, author = {Liu, S and Lu, X and Dai, M and Zhang, S}, title = {Transcription factor CreA is involved in the inverse regulation of biofilm formation and asexual development through distinct pathways in Aspergillus fumigatus.}, journal = {Molecular microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mmi.15179}, pmid = {37800624}, issn = {1365-2958}, support = {NSFC32170040//National Natural Science Foundation of China/ ; //Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions/ ; }, abstract = {The exopolysaccharide galactosaminogalactan (GAG) contributes to biofilm formation and virulence in the pathogenic fungus Aspergillus fumigatus. Increasing evidence indicates that GAG production is inversely linked with asexual development. However, the mechanisms underlying this regulatory relationship are unclear. In this study, we found that the dysfunction of CreA, a conserved transcription factor involved in carbon catabolite repression in many fungal species, causes abnormal asexual development (conidiation) under liquid-submerged culture conditions specifically in the presence of glucose. The loss of creA decreased GAG production independent of carbon sources. Furthermore, CreA contributed to asexual development and GAG production via distinct pathways. CreA promoted A. fumigatus GAG production by positively regulating GAG biosynthetic genes (uge3 and agd3). CreA suppressed asexual development in glucose liquid-submerged culture conditions via central conidiation genes (brlA, abaA, and wetA) and their upstream activators (flbC and flbD). Restoration of brlA expression to the wild-type level by flbC or flbD deletion abolished the abnormal submerged conidiation in the creA null mutant but did not restore GAG production. The C-terminal region of CreA was crucial for the suppression of asexual development, and the repressive domain contributed to GAG production. Overall, CreA is involved in GAG production and asexual development in an inverse manner.}, } @article {pmid37799886, year = {2023}, author = {Li, H and Liu, H and Zhang, L and Hieawy, A and Shen, Y}, title = {Evaluation of extracellular polymeric substances matrix volume, surface roughness and bacterial adhesion property of oral biofilm.}, journal = {Journal of dental sciences}, volume = {18}, number = {4}, pages = {1723-1730}, pmid = {37799886}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: Oral biofilms are highly structured bacterial colonies embedded in a highly hydrated extracellular polymeric substances (EPS) matrix. This study aimed to investigate the characteristics of oral biofilm at different stages of maturation.

MATERIALS AND METHODS: Oral multispecies biofilms were grown anaerobically from plaque bacteria on collagen coated hydroxyapatite discs in brain heart infusion broth for one and three weeks. The volume of live bacteria and EPS matrix of the biofilms were determined by using corresponding fluorescent probes and confocal laser scanning microscopy. Atomic force microscopy (AFM) was used to quantitatively probe and correlate cell surface adhesion force of biofilms. The surface roughness was quantified in terms of the root mean square average of the height deviations. Adhesion was measured from force-distance data for the retraction of the cell from the surface.

RESULTS: The volume of live bacteria and EPS of 3-week-old biofilms was higher than 1-week-old biofilms. The surface roughness value in 1-week-old biofilms was significantly higher than that in 3-week-old biofilms. AFM force-distance curve results showed that the adhesion force at the cell-cell interface was significantly more at-tractive than those at bacterial cells surface of both stages biofilms. Adhesion forces between the AFM tip and the surface of bacterial cell were fairly constant, whereas the cell-cell interface experienced greater adhesion forces in the biofilm's development.

CONCLUSION: As oral biofilms become mature, EPS volume and cell-cell adhesion forces increase while the surface roughness decreases.}, } @article {pmid37798713, year = {2023}, author = {Mlugu, EM and Mohamedi, JA and Sangeda, RZ and Mwambete, KD}, title = {Prevalence of urinary tract infection and antimicrobial resistance patterns of uropathogens with biofilm forming capacity among outpatients in morogoro, Tanzania: a cross-sectional study.}, journal = {BMC infectious diseases}, volume = {23}, number = {1}, pages = {660}, pmid = {37798713}, issn = {1471-2334}, abstract = {INTRODUCTION: Urinary tract infection (UTI) is the second most common infectious disease affecting more than 150 million people globally annually. Uropathogenic E. coli (UPEC), the predominant cause of UTI, can occur as a biofilm associated with antimicrobial resistance (AMR). There is a data gap on global AMR patterns from low-income settings, including Tanzania. Data on antimicrobial susceptibility patterns in relation to biofilm formation will help in the proper selection of antibiotics and the fight against AMR.

METHODS: This analytical cross-sectional study was conducted among consecutively selected outpatients (n = 344) from January to May 2022 at Morogoro Regional Referal Hospital. Mid-stream urine samples were collected aseptically from symptomatic patients. A significant UTI was defined when more than 10[5] colonies/ml of urine were recorded. Kirby Bauer's disc diffusion method was used for antibiotics susceptibility patterns and a Congo Red Agar method was used to determine biofilm formation. Two-sided χ2 test or Fisher's exact test, Cohen's kappa coefficient and logistic regression were used for data analysis. A p-value < 0.05 was considered statistically significant.

RESULTS: The prevalence of UTIs was 41% (141/344) and elders (>=60 years) had five times higher odds of having UTI as compared to adolescents (p < 0.001). E. coli was the most predominant bacteria (47%; 66/141), which displayed moderate susceptibility against ciprofloxacin (59.1%) and nitrofurantoin (57.6%). A total of 72 (51%) of all isolated bacteria were multi-drug resistant. All isolated bacteria demonstrated high resistance (> 85%) against ampicillin and co-trimoxazole. In this study, 51.5% (34/66) were biofilm-forming E. coli and demonstrated relatively higher antibiotic resistance as compared to non-biofilm forming bacteria (p < 0.05).

CONCLUSION: We report high antibiotic resistance against commonly used antibiotics. Slightly more than half of the isolated bacteria were biofilm forming E. coli. A need to strengthen stewardship programs is urgently advocated.}, } @article {pmid37797924, year = {2023}, author = {Zhang, W and Wu, H and Ping, Q and Wen, R and Jin, Y}, title = {Application of positively charged red mud-based carriers for anaerobic ammonium oxidizing bacteria biofilm formation.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122692}, doi = {10.1016/j.envpol.2023.122692}, pmid = {37797924}, issn = {1873-6424}, abstract = {Enrichment of anaerobic ammonium oxidizing bacteria (AnAOB) in the anaerobic ammonium oxidation (anammox) process remains a challenge in engineering applications. In this study, for faster enrichment of AnAOB, red mud-based carriers were positively charged with FeCl3 and microbial promoters. The experimental results showed that the average nitrogen removal rates of the red mud-based carriers (RMGA), FeCl3-modified red mud-based carriers (RMGA-Fe), and microbial promoter-modified red mud-based carriers (RMGA-MA) increased by 24.4%-175% compared with the commercially available K3 carriers. Combining the results of SEM and laser confocal microscope, electrostatic attraction played a leading role on loading AnAOB. The increase in the surface roughness and specific area of the carriers after the attachment and the presence of Fe[2+], Ca[2+], and Mg[2+] plasma were necessary for the subsequent growth of AnAOB, while the leaching of Cr(VI) promoted the nitrogen removal effect of AnAOB.}, } @article {pmid37797554, year = {2023}, author = {Zhai, H and Yeo, J}, title = {Controlling biofilm transport with porous metamaterials designed with Bayesian learning.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {147}, number = {}, pages = {106127}, doi = {10.1016/j.jmbbm.2023.106127}, pmid = {37797554}, issn = {1878-0180}, abstract = {Biofilm growth and transport in confined systems frequently occur in natural and engineered systems. Designing customizable engineered porous materials for controllable biofilm transportation properties could significantly improve the rapid utilization of biofilms as engineered living materials for applications in pollution alleviation, material self-healing, energy production, and many more. We combine Bayesian optimization (BO) and individual-based modeling to conduct design optimizations for maximizing different porous materials' (PM) biofilm transportation capability. We first characterize the acquisition function in BO for designing 2-dimensional porous membranes. We use the expected improvement acquisition function for designing lattice metamaterials (LM) and 3-dimensional porous media (3DPM). We find that BO is 92.89% more efficient than the uniform grid search method for LM and 223.04% more efficient for 3DPM. For all three types of structures, the selected characterization simulation tests are in good agreement with the design spaces approximated with Gaussian process regression. All the extracted optimal designs exhibit better biofilm growth and transportability than unconfined space without substrates. Our comparison study shows that PM stimulates biofilm growth by taking up volumetric space and pushing biofilms' upward growth, as evidenced by a 20% increase in bacteria cell numbers in unconfined space compared to porous materials, and 128% more bacteria cells in the target growth region for PM-induced biofilm growth compared with unconfined growth. Our work provides deeper insights into the design of substrates to tune biofilm growth, analyzing the optimization process and characterizing the design space, and understanding biophysical mechanisms governing the growth of biofilms.}, } @article {pmid37798682, year = {2023}, author = {Parakaw, T and Ruangsawasdi, N and Dararat, P and Phruksaniyom, C and Srihirun, S and Petchmedyai, P}, title = {Biocompatibility and biofilm formation on conventional and CAD/CAM provisional implant restorations.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {718}, pmid = {37798682}, issn = {1472-6831}, abstract = {Dental implant treatment is a complex and sophisticated process, and implant provisional restorations play a vital role in ensuring its success. The advent of computer-aided design and computer-aided manufacturing (CAD/CAM) technology has revolutionized the field of implant restorations by providing improved precision leading to a reduction in chair time and more predictable treatment outcomes. This technology offers a promising solution to the drawbacks of conventional methods and has the potential to transform the way implant procedures are approached. Despite the clear advantages of CAD/CAM over conventional provisional implant restorations including higher accuracy of fit and superior mechanical properties, little research has been conducted on the biological aspect of these novel restorations. This study aims to fill that gap, comprehensively assessing the biocompatibility, gingival tissue attachment and biofilm formation of a range of provisional implant restorations using CAD/CAM technology through milling and 3-D printing processes compared to conventional fabrication. The biocompatibility of the tested restorations was assessed by MTT assay, Calcein-AM assay as well as SEM analysis. The surface roughness of the tested samples was evaluated, alongside the attachment of Human Gingival Fibroblasts (HGF) cells as well as biofilm formation, and estimated Porphyromonas gingivalis (P. gingivalis) cell count from DNA detection.The results showed all tested provisional implant restorations were non-toxic and good HGF cell attachment but differed in their quantity of biofilm formation, with surface texture influenced by the material and fabrication technique, playing a role. Within the limitation of this study, the findings suggest that CAD/CAM-fabricated provisional implant restorations using a milling technique may be the most favourable among tested groups in terms of biocompatibility and periodontal-related biofilm formation.}, } @article {pmid37798613, year = {2023}, author = {Valadbeigi, H and Sadeghifard, N and Kaviar, VH and Haddadi, MH and Ghafourian, S and Maleki, A}, title = {Effect of ZnO nanoparticles on biofilm formation and gene expression of the toxin-antitoxin system in clinical isolates of Pseudomonas aeruginosa.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {22}, number = {1}, pages = {89}, pmid = {37798613}, issn = {1476-0711}, abstract = {BACKGROUND: Biofilm formation by Pseudomonas aeruginosa (P. aeruginosa) is known to be characteristic of this organism. This bacterium is considered one of the most life-threatening bacteria and has been identified as a priority pathogen for research by WHO. Biofilm-producing P. aeruginosa is a concern in many parts of the world due to antibiotic resistance. Alginate also plays an important role in the biofilm formation of P. aeruginosa as well as the emergence of antibiotic resistance in biofilms. In addition, the systems of toxin-antitoxin(TA) play an important role in biofilm formation. Metal nanoparticle(NP) such as zinc oxide (ZnO) also have extensive biological properties, especially anti-biofilm properties. Therefore, this study was conducted in relation to the importance of zinc oxide nanoparticles (ZnO NPs) in biofilm formation and also the correlation of gene expression of TA systems in clinical isolates of P. aeruginosa.

METHODS: A total of 52 P. aeruginosa isolates were collected from burns (n = 15), UTI (n = 31), and trachea (n = 6) in hospitals in Ilam between May 2020 and October 2020. Biofilm formation was assessed using a microtiter plate assay. MIC and sub-MIC concentrations of ZnO NPs (10-30 nm with purity greater than 99.8%) in P. aeruginosa were determined. Subsequently, biofilm formation was investigated using sub-MIC concentrations of ZnO NPs. Finally, total RNA was extracted and RT- qPCR was used to determine the expression levels of genes of mazEF, mqsRA, and higBA of TA systems.

RESULTS: Six isolates of P. aeruginosa were found to form strong biofilms. The results showed that ZnO NPs were able to inhibit biofilm formation. In our experiments, we found that the sub-MIC concentration of ZnO NPs increased the gene expression of antitoxins mazE and mqsA and toxin higB of TA systems treated with ZnO NPs.

CONCLUSIONS: In the present study, ZnO NPs were shown to effectively inhibit biofilm formation in P. aeruginosa. Our results support the relationship between TA systems and ZnO NPs in biofilm formation in P. aeruginosa. Importantly, the expression of antitoxins mazE and mqsA was high after treatment with ZnO NPs, but not that of antitoxin higA.}, } @article {pmid37798606, year = {2023}, author = {Byeon, CH and Akbey, Ü}, title = {Solution-state NMR assignment and secondary structure analysis of the monomeric Pseudomonas biofilm-forming functional amyloid accessory protein FapA.}, journal = {Biomolecular NMR assignments}, volume = {}, number = {}, pages = {}, pmid = {37798606}, issn = {1874-270X}, abstract = {FapA is an accessory protein within the biofilm forming functional bacterial amyloid related fap-operon in Pseudomonas, and maybe a chaperone for FapC controlling its fibrillization. To allow further structural analysis, here we present a complete sequential assignment of [1]Hamide, [13]Cα, [13]Cβ, and [15]N NMR resonances for the functional form of the monomeric soluble FapA protein, comprising amino acids between 29 and 152. From these observed chemical shifts, the secondary structure propensities (SSPs) were determined. FapA predominantly adopts a random coil conformation, however, we also identified small propensities for α-helical and β-strand conformations. Notably, these observed SSPs are smaller compared to the ones we recently observed for the monomeric soluble FapC protein. These NMR results provide valuable insights into the activity of FapA in functional amyloid formation and regulation, that will also aid developing strategies targeting amyloid formation within biofilms and addressing chronic infections.}, } @article {pmid37796898, year = {2023}, author = {Chen, S and Ding, Y}, title = {A bibliography study of Shewanella oneidensis biofilm.}, journal = {FEMS microbiology ecology}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsec/fiad124}, pmid = {37796898}, issn = {1574-6941}, abstract = {This study employs a bibliography study method to evaluate 472 papers focused on Shewanella oneidensis biofilms. Biofilms, which are formed when microorganisms adhere to surfaces or interfaces, play a crucial role in various natural, engineered, and medical settings. Within biofilms, microorganisms are enclosed in extracellular polymeric substances (EPS), creating a stable working environment. This characteristic enhances the practicality of biofilm-based systems in natural bioreactors, as they are less susceptible to temperature and pH fluctuations compared to enzyme-based bioprocesses. S. oneidensis, a non-pathogenic bacterium with the ability to transfer electrons, serves as an example of a species isolated from its environment that exhibits extensive biofilm applications. These applications, such as heavy metal removal, offer potential benefits for environmental engineering and human health. This paper presents a comprehensive examination and review of the biology and engineering aspects of Shewanella biofilms, providing valuable insights into their functionality.}, } @article {pmid37796007, year = {2023}, author = {Tan, X and Cheng, X and Xiao, J and Liu, Q and Du, D and Li, M and Sun, Y and Zhou, J and Zhu, G}, title = {Alkaline phosphatase LapA regulates quorum sensing-mediated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 under phosphate depletion stress.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0206023}, doi = {10.1128/spectrum.02060-23}, pmid = {37796007}, issn = {2165-0497}, abstract = {Among various environmental stresses, the depletion of inorganic phosphate, which is an important signaling molecule that modulates virulence production, is notable. In our previous study, we demonstrated that lapA, encoding alkaline phosphatase, plays a key role in Pseudomonas aeruginosa biofilm formation in porcine skin explants, an ex vivo chronic wound model. However, the mechanism by which lapA participates in the virulence and biofilm formation of P. aeruginosa remains unclear. In the present study, the lapA deletion mutant was constructed in P. aeruginosa PAO1, and the phenotypic characterization was assessed. Our data demonstrated that phosphate depletion stress significantly enhanced elastase activity, hemolysis, rhamnolipid production, swarming and swimming motilities, and 3-oxo-C12-homoserine lactone (HSL) production in P. aeruginosa. Moreover, phosphate starvation evidently induced the virulence of P. aeruginosa in Caenorhabditis elegans (C. elegans) through fast-kill and slow-kill infections. Deletion of the lapA gene led to broad phenotypic changes, including reduced elastase activity, swimming motility, C4-HSL, and 3-oxo-C12-HSL production, as well as increased chitinase activity and rhamnolipid production under phosphate depletion stress, which was unrelated to C4-HSL. Deletion of the lapA gene also significantly inhibited PAO1 biofilm formation in porcine skin explants by reducing the expression levels of las and rhl quorum sensing systems and extracellular polymeric substance synthesis. Finally, lapA deletion also reduced the virulence of PAO1 in C. elegans in fast-kill and slow-kill infection assays. Thus, the findings suggest that targeting lapA can help control biofilm formation and reduce virulence in nonhealing-infected wounds, where P. aeruginosa is a persistent problem. IMPORTANCE Our previous study demonstrated that the expression of lapA was induced under phosphate depletion conditions, but its roles in virulence and biofilm formation by Pseudomonas aeruginosa remain largely unknown. This study presents a systematic investigation of the roles of lapA in virulence induction and biofilm formation by constructing a lapA-deficient strain with P. aeruginosa PAO1. The results showed that deletion of the lapA gene evidently reduced elastase activity, swimming motility, C4-HSL, and 3-oxo-C12-HSL production, and increased rhamnolipid production under phosphate depletion stress. Moreover, lapA gene deletion inhibited PAO1 biofilm formation in porcine skin explants by reducing the expression levels of las and rhl quorum sensing systems and extracellular polymeric substance synthesis. Finally, lapA gene deletion also reduced the virulence of PAO1 in Caenorhabditis elegans in fast-kill and slow-kill infection assays. This study provides insights into the roles of lapA in modulating P. aeruginosa virulence and biofilm formation under phosphate depletion stress.}, } @article {pmid37795651, year = {2023}, author = {Kim, J and Wang, J and Ahn, J}, title = {Combined antimicrobial effect of phage-derived endolysin and depolymerase against biofilm-forming Salmonella Typhimurium.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2023.2265817}, pmid = {37795651}, issn = {1029-2454}, abstract = {This study was designed to evaluate the antimicrobial activity of phage-derived endolysin (LysPB32) and depolymerase (DpolP22) against planktonic and biofilm cells of Salmonella Typhimurium (ST[KCCM]). Compared to the control, the numbers of ST[KCCM] were reduced by 4.3 and 5.9 log, respectively, at LysPB32 and LysPB32 + DpolP22 in the presence of polymyxin B (PMB) after 48-h incubation at 37 °C. LysPB32 + DpolP22 decreased the relative fitness (0.8) and the cross-resistance of ST[KCCM] to chloramphenicol (CHL), cephalothin (CEP), ciprofloxacin (CIP), and tetracycline (TET) in the presence of PMB. The MICtrt/MICcon ratios of CHL, CEP, CIP, PMB, and TET were between 0.25 and 0.50 for LysPB32 + DpolP22 in the presence of PMB. These results suggest that the application of phage-encoded enzymes with antibiotics can be a promising approach for controlling biofilm formation on medical and food-processing equipment. This is noteworthy in that the application of LysPB32 + DpolP22 could increase antibiotic susceptibility and decrease cross-resistance to other antibiotics.}, } @article {pmid37793587, year = {2023}, author = {Ni, M and Pan, Y and Li, D and Huang, Y and Chen, Z and Li, L and Bi, Z and Wu, R and Song, Z}, title = {Metagenomics, metatranscriptomics, and proteomics reveal the metabolic mechanism of biofilm sequencing batch reactor with higher phosphate enrichment capacity under low phosphorus load.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117237}, doi = {10.1016/j.envres.2023.117237}, pmid = {37793587}, issn = {1096-0953}, abstract = {The biofilm sequencing batch reactor (BSBR) process has higher phosphate recovery efficiency and enrichment multiple when the phosphorus load is lower, but the mechanism of phosphate enrichment at low phosphorus load remains unclear. In this study, we operated two BSBR operating under low and high phosphorus load (0.012 and 0.032 kg/(m[3]·d)) respectively, and used metagenomic, metatranscriptomic, and proteomics methods to analyze the community structure of the phosphorus accumulating organisms (PAOs) in the biofilm, the transcription and protein expression of key functional genes and enzymes, and the metabolism of intracellular polymers. Compared with at high phosphorus load, the BSBR at low phosphorus load have different PAOs and fewer types of PAOs, but in both cases the PAOs must have the PHA, PPX, Pst, and acs genes to become dominant. Some key differences in the metabolism of PAOs from the BSBR with different phosphorus load can be identified as follows. When the phosphorus load is low, the adenosine triphosphoric acid (ATP) and NAD(P)H in the anaerobic stage come from the TCA cycle and the second half of the EMP pathway. The key genes that are upregulated include GAPDH, PGK, ENO, ppdk in the EMP pathway, actP in acetate metabolism, phnB in polyhydroxybutyrate (PHB) synthesis, and aceA, mdh, sdhA, and IDH1 in the TCA cycle. In the meantime, the ccr gene in the PHV pathway is inhibited. As a result, the metabolism of the PAOs features low glycogen with high PHB, Pupt, Prel, and low PHV. That is, more ATP and NAD(P)H flow to phosphorus enrichment metabolism, thus allowing the highly efficient enrichment of phosphorus from low concentration phosphate thanks to the higher abundance of PAOs. The current results provide theoretical support and a new technical option for the enrichment and recovery of low concentrations of phosphate from wastewater by the BSBR process.}, } @article {pmid37792886, year = {2023}, author = {Silva, MDDD and Nunes, TSBS and Viotto, HEDC and Coelho, SRG and Souza, RF and Pero, AC}, title = {Microbial adhesion and biofilm formation by Candida albicans on 3D-printed denture base resins.}, journal = {PloS one}, volume = {18}, number = {10}, pages = {e0292430}, doi = {10.1371/journal.pone.0292430}, pmid = {37792886}, issn = {1932-6203}, abstract = {This study evaluated surface properties and adhesion/biofilm formation by Candida albicans on 3D printed denture base resins used in 3D printing. Disc-shaped specimens (15 mm x 3 mm) of two 3D-printed resins (NextDent Denture 3D+, NE, n = 64; and Cosmos Denture, CO, n = 64) and a heat-polymerized resin (Lucitone 550, LU, control, n = 64) were analyzed for surface roughness (Ra μm) and surface free energy (erg cm-2). Microbiologic assays (90-min adhesion and 48-h biofilm formation by C. albicans) were performed five times in triplicate, with the evaluation of the specimens' surface for: (i) colony forming units count (CFU/mL), (ii) cellular metabolism (XTT assay), and (iii) fluorescence and thickness of biofilm layers (confocal laser scanning microscopy). Data were analyzed using parametric and nonparametric tests (α = 0.05). LU presented higher surface roughness Ra (0.329±0.076 μm) than NE (0.295±0.056 μm) (p = 0.024), but both were similar to CO (0.315±0.058 μm) (p = 1.000 and p = 0.129, respectively). LU showed lower surface free energy (47.47±2.01 erg cm-2) than CO (49.61±1.88 erg cm-2) and NE (49.23±2.16 erg cm-2) (p<0.001 for both). The CO and NE resins showed greater cellular metabolism (p<0.001) and CO only, showed greater colonization (p = 0.015) by C. albicans than LU in the 90-min and 48-hour periods. It can be concluded that both 3D-printed denture base resins are more prone to colonization by C. albicans, and that their surface free energy may be more likely associated with that colonization than their surface roughness.}, } @article {pmid37792174, year = {2023}, author = {Govindan, R and Gnanasekaran, C and Govindan, R and Muthuchamy, M and Quero, F and Jothi, A and Chelliah, CK and Arunachalam, A and Viswanathan, MR and Natesan, M and Kadaikunnan, S and Li, WJ}, title = {Anti-quorum Sensing and Anti-biofilm Effect of Nocardiopsis synnemataformans RMN 4 (MN061002) Compound 2,6-Di-tert-butyl, 1,4-Benzoquinone Against Biofilm-Producing Bacteria.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37792174}, issn = {1559-0291}, support = {41950410573//National Natural science Foundation of China/ ; 2019M663213//Post Doctoral Science Foundation of China/ ; 3220019//Universidad de Chile/ ; RSPD2023R696//King's University College/ ; }, abstract = {In this study, the anti-biofilm compound of 2,6-Di-tert-butyl, 1,4-benzoquinone was purified from Nocardiopsis synnemataformans (N. synnemataformans) RMN 4 (MN061002). To confirm the compound, various spectroscopy analyses were done including ultraviolet (UV) spectrometer, Fourier transform infrared spectroscopy (FTIR), analytical high-performance liquid chromatography (HPLC), preparative HPLC, gas chromatography-mass spectroscopy (GC-MS), liquid chromatography-mass spectroscopy (LC-MS), and 2D nuclear magnetic resonance (NMR). Furthermore, the purified compound was shown 94% inhibition against biofilm-producing Proteus mirabilis (P. mirabilis) (MN396686) at 70 µg/mL concentrations. Furthermore, the metabolic activity, exopolysaccharide damage, and hydrophobicity degradation results of identified compound exhibited excellent inhibition at 100 µg/mL concentration. Furthermore, the confocal laser scanning electron microscope (CLSM) and scanning electron microscope (SEM) results were shown with intracellular damages and architectural changes in bacteria. Consecutively, the in vivo toxicity effect of the compound against Artemia franciscana (A. franciscana) was shown to have a low mortality rate at 100 µg/mL. Finally, the molecular docking interaction between the quorum sensing (QS) genes and identified compound clearly suggested that the identified compound 2,6-Di-tert-butyl, 1,4-benzoquinone has anti-quorum sensing and anti-biofilm activities against P. mirabilis (MN396686).}, } @article {pmid37791754, year = {2023}, author = {Ferguson, DL and Gloag, ES and Parsek, MR and Wozniak, DJ}, title = {Extracellular DNA enhances biofilm integrity and mechanical properties of mucoid Pseudomonas aeruginosa.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0023823}, doi = {10.1128/jb.00238-23}, pmid = {37791754}, issn = {1098-5530}, abstract = {Pseudomonas aeruginosa is one of the most common biofilm-forming pathogens responsible for lung infections of individuals with cystic fibrosis (CF). P. aeruginosa becomes tolerant to antimicrobials in the biofilm state and is difficult to treat. Production of extracellular polymeric substances (EPS), such as alginate and extracellular DNA (eDNA), can allow adherence to abiotic and biotic surfaces, antimicrobial evasion, and resilience to environmental pressures. Alginate-producing mucoid variants of P. aeruginosa are frequently isolated from CF airway samples and are associated with worsening patient outcomes. While eDNA is a major structural component of nonmucoid P. aeruginosa biofilms, the potential role of eDNA in mucoid biofilms is unclear. Here, we investigate how eDNA contributes to clinical mucoid biofilm physiology and integrity. We predicted that eDNA plays a structural and mechanical role in mucoid biofilms. To test this, we quantified biofilm eDNA in mucoid biofilms and used microscopy and rheology to visualize eDNA and detect changes in biofilm structure and mechanics upon DNaseI treatment. We showed that biofilm eDNA abundance is diverse across clinical mucoid strains and observed a temporal increase in foci of eDNA within intact mucoid biofilms. Increased cell dispersal and reduced biomass were also observed following DNaseI treatment of mucoid biofilms. Degradation of eDNA also impacted the mechanical integrity of mucoid biofilms by increasing the stiffness and decreasing the cohesion of the biofilm. These findings advance our understanding of clinical mucoid P. aeruginosa biofilms and facilitate the development of new approaches to target biofilms by exploiting the functions of EPS components. IMPORTANCE Understanding the role of eDNA in mucoid Pseudomonas aeruginosa biofilms will lead to therapeutic strategies that combat the biophysical and structural function of EPS for the eradication of bacteria in mucoid biofilms during chronic infections. This knowledge can be used to further identify unknown matrix component interactions within pathogenic biofilm-forming clinical isolates.}, } @article {pmid37790732, year = {2023}, author = {Bennett, AN and Woolard, KJ and Sorge, A and Melander, C and Gunn, JS}, title = {Spectrum of activity of Salmonella anti-biofilm compounds: Evaluation of activity against biofilm-forming ESKAPE pathogens.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100158}, pmid = {37790732}, issn = {2590-2075}, abstract = {The ESKAPE pathogens are a group of bacteria that are a leading cause of health-care associated infections and are known to be agents of chronic, biofilm-mediated infections. These chronic bacterial infections often respond poorly to antibiotics and in some cases may require surgical intervention in order to cure the infection. As biofilms are often the critical mediator of a chronic infection, it is essential to develop therapies that target bacteria within the biofilm state. Herein, we report the development of a rapid, 96-well plate-based assay that employs conditions specific for each species to optimize biofilm production and allow for easy identification of differences in biofilm mass after treatment with anti-biofilm candidates. We used these ESKAPE-specific biofilm assays to test our previously identified Salmonella anti-biofilm small molecule compounds, JG-1 and M4, for anti-biofilm activity. The results demonstrated that JG-1 and M4 have anti-biofilm activity against Enterobacter spp., S. aureus, E. faecium, P. aeruginosa, and A. baumannii. In addition, we identified that M4 has significant antimicrobial activity against S. aureus and E. faecium at concentrations >10 μM (X μg/mL). These findings support the claim that JG-1 and M4 have broad-spectrum anti-biofilm activity, while M4 has antimicrobial activity against the Gram-positive members of the ESKAPE pathogens. Thus, these compounds have the potential to have a significant impact on treating multiple types of commonly encountered biofilm-mediated infections.}, } @article {pmid37789212, year = {2023}, author = {Bunma, C and Noinarin, P and Phetcharaburanin, J and Chareonsudjai, S}, title = {Burkholderia pseudomallei biofilm resists Acanthamoeba sp. grazing and produces 8-O-4'-diferulic acid, a superoxide scavenging metabolite after passage through the amoeba.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {16578}, pmid = {37789212}, issn = {2045-2322}, support = {Scholarship #592008//Development and Promotion of Science and Technology Talents Project, Royal Thai Government, Bangkok, Thailand/ ; }, abstract = {Burkholderia pseudomallei, an etiological agent of melioidosis is an environmental bacterium that can survive as an intracellular pathogen. The biofilm produced by B. pseudomallei is crucial for cellular pathogenesis of melioidosis. The purpose of this investigation is to explore the role of biofilm in survival of B. pseudomallei during encounters with Acanthamoeba sp. using B. pseudomallei H777 (a biofilm wild type), M10 (a biofilm defect mutant) and C17 (a biofilm-complemented strain). The results demonstrated similar adhesion to amoebae by both the biofilm wild type and biofilm mutant strains. There was higher initial internalisation, but the difference diminished after longer encounter with the amoeba. Interestingly, confocal laser scanning microscopy demonstrated that pre-formed biofilm of B. pseudomallei H777 and C17 were markedly more persistent in the face of Acanthamoeba sp. grazing than that of M10. Metabolomic analysis revealed a significant increased level of 8-O-4'-diferulic acid, a superoxide scavenger metabolite, in B. pseudomallei H777 serially passaged in Acanthamoeba sp. The interaction between B. pseudomallei with a free-living amoeba may indicate the evolutionary pathway that enables the bacterium to withstand superoxide radicals in intracellular environments. This study supports the hypothesis that B. pseudomallei biofilm persists under grazing by amoebae and suggests a strategy of metabolite production that turns this bacterium from saprophyte to intracellular pathogen.}, } @article {pmid37788717, year = {2023}, author = {Gao, S and Shen, Y and Yuan, S and Quan, Y and Li, X and Wang, Y and Yi, L and Wang, Y}, title = {Methyl anthranilate deteriorates biofilm structure of Streptococcus suis and antagonizes the capsular polysaccharides-defense effect.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106996}, doi = {10.1016/j.ijantimicag.2023.106996}, pmid = {37788717}, issn = {1872-7913}, abstract = {BACKGROUND: Streptococcus suis (S. suis) is an important zoonotic pathogen that often causes biofilm associated infection. Bacterial biofilm-dependent infection is associated with enhanced drug resistance, making it difficult to eradicate. Novel therapeutic approaches are urgently required to treat S. suis biofilm-associated infection. This study aimed to investigate the effects and mechanisms of methyl anthranilate (MA) on S. suis biofilm.

METHODS: The effect of MA on S. suis biofilm was determined by crystal violet method, and the microstructure of the biofilm was observed by electron microscopy. The effects on capsular polysaccharides was determined by phenol-sulfuric acid method and high performance liquid chromatography. Adhesion and anti-phagocytosis properties of S. suis were detected via cell assays. Molecular docking, molecular dynamics simulation and enzyme activity inhibition assays were used to further explored the effect of MA on AI-2 quorum sensing (QS) of S. suis. Finally, the therapeutic effect of MA was investigated using a mouse infection model.

RESULTS: MA destroyed the structure of S. suis biofilm, hindered biofilm formation, and significantly reduced capsular polysaccharides synthesis, which further weakened the adhesion and anti-phagocytosis ability of S. suis. MA had a docking effect and binding site (SER76 and ASP197) similar to SAH, further analysis showed that MA competitively bound 5'-methyladenosine/S-adenosine homocysteine nucleosidase (PFS) with SAH to interfere with AI-2 QS. In a mouse model, MA effectively reduced the bacterial burden and inflammatory infiltrates.

CONCLUSION: This study revealed the antibiofilm effects of MA and highlighted its potential as a quorum sensing inhibitor against S. suis infection.}, } @article {pmid37788986, year = {2023}, author = {Howard, SA and McCarthy, RR}, title = {Modulating biofilm can potentiate activity of novel plastic-degrading enzymes.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {72}, pmid = {37788986}, issn = {2055-5008}, support = {SBF006\1040/AMS_/Academy of Medical Sciences/United Kingdom ; }, abstract = {Plastic pollution is an increasing global issue desperately requiring a solution. Only 9% of all plastic waste has been recycled, and whilst recycling gives a second life to plastic, it is costly and there are limited downstream uses of recycled plastic, therefore an alternative is urgently needed. Biodegradation of plastic by microorganisms is a developing field of interest with the potential for bioreactors to be used alongside recycling to degrade plastic that may otherwise be sent to landfill. Here, we have identified two novel polyethylene terephthalate (PET) degrading enzymes through genomic mining and characterised their activity, including their ability to degrade PET. One of the main roadblocks facing the development of microbial enzymes as a plastic biodegradation solution, is that their efficiency is too low to facilitate development as bioremediation tools. In an innovative approach to tackle this roadblock, we hypothesised that enhancing a bacteria's ability to attach to and form a biofilm on plastic could maximise the local concentration of the enzyme around the target substrate, therefore increasing the overall rate of plastic degradation. We found that increasing biofilm levels, by manipulating the levels of the second messenger, Cyclic-di-GMP, led to increased levels of polyester degradation in cells expressing novel and well characterised polyester-degrading enzymes. This indicates that modulating biofilm formation is a viable mechanism to fast track the development of bacterial plastic bioremediation solutions.}, } @article {pmid37788168, year = {2023}, author = {Musiol, R}, title = {Efflux systems as a target for anti-biofilm nanoparticles: perspectives on emerging applications.}, journal = {Expert opinion on therapeutic targets}, volume = {}, number = {}, pages = {1-11}, doi = {10.1080/14728222.2023.2263910}, pmid = {37788168}, issn = {1744-7631}, abstract = {INTRODUCTION: Understanding the role of efflux pumps in biofilm resistance provides valuable insights for developing effective therapeutic strategies. Drugs designed for targeting efflux pumps in drug design holds promise for combating biofilm-related infections. Nanoparticles offer unparalleled advantages in designing drugs targeting efflux pumps.

AREAS COVERED: This review rigorously examines the existing body of knowledge on the prospective targeting of efflux pumps using metal-based nanoparticles. It includes and analyses the pertinent research findings sourced from the PubMed and SciFinder databases. It covers the experimental studies on efflux inhibition by nanoparticles and provides detailed analyses of their mechanisms of action, elucidating their interactions with the efflux system and their influence on biofilm formation and persistence.

EXPERT OPINION: The potential of nanoparticles to act as potent antibacterial agents through efflux pump inhibition remains tantalizing, although hindered by limited mechanistic understanding. From the burgeoning research landscape nanoparticles emerge as a novel direction for shaping antimicrobial drug design. Notably, beyond their contribution to drug resistance, efflux pumps play a pivotal role in biofilm development. The deliberate disruption of these pumps can effectively reduce biofilm adhesion and maturation. More details however are needed to exploit this potential.}, } @article {pmid37787204, year = {2023}, author = {Sai, S and Nivedha, RT and Narasimhan, S and Veronica, AK and Selvakumar, J and Susila, AV}, title = {Customised enriched coconut oil as panacea for oral biofilm mediated diseases - A prospective study.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {34}, number = {2}, pages = {159-163}, doi = {10.4103/ijdr.ijdr_955_22}, pmid = {37787204}, issn = {1998-3603}, abstract = {AIMS: To evaluate a customised enriched formulation of coconut (CEC) oil with Arimedadi Tailam (AT) and 0.2% chlorhexidine mouth rinse (CHX) for their plaque control and potential anticaries effects using the oratest in healthy volunteers.

SETTINGS AND DESIGN: Parallel, double-blinded (outcome assessor and statistician), randomised controlled institution-based pilot study.

METHODS AND MATERIALS: 60 adults (18-22 years) having DMFT score of 2-11, gingival and plaque index as zero, no history of antibiotics for one month or fluoride application in 2 weeks were randomly divided (computer-generated list) and allocated into 3 groups (A-CHX, B-CEC, C-AT) of 20 subjects each based on the intervention. Oratest at baseline, days 15 and 30 were recorded.

STATISTICAL ANALYSIS USED: Due to 5 dropouts on day 30, data were analysed based on the intention-to-treat (ITT) approach. The difference in oratest scores (baseline vs. day 15 and 30) were found to be normally distributed (Shapiro-Wilk test and Levene's test). One way ANOVA followed by Tukey's post hoc test was used to determine the statistically significant difference (P < 0.05) between groups.

RESULTS: Plaque and gingival index was zero throughout the study period. Difference in oratest scores was highest with CEC oil, followed by CHX and AT though there was no statistically significant differences between groups at baseline vs day 15 (P = 0.203) and baseline vs day 30 (P = 0.085) and between oils from baseline vs day 30 (P = 0.068).

CONCLUSIONS: Within the limitations of the pilot study, both oils are comparable to CHX for their antiplaque and anticaries potential. Clinically, CEC was better than AT though statistical difference was not there.}, } @article {pmid37782357, year = {2023}, author = {Pan, I and Umapathy, S and Issac, PK and Rahman, MM and Guru, A and Arockiaraj, J}, title = {The bioaccessibility of adsorped heavy metals on biofilm-coated microplastics and their implication for the progression of neurodegenerative diseases.}, journal = {Environmental monitoring and assessment}, volume = {195}, number = {11}, pages = {1264}, pmid = {37782357}, issn = {1573-2959}, mesh = {Humans ; *Neurodegenerative Diseases ; Plastics ; Microplastics ; Ecosystem ; Environmental Monitoring ; *Metals, Heavy ; Biofilms ; }, abstract = {Microplastic (MP) tiny fragments (< 5 mm) of conventional and specialized industrial polymers are persistent and ubiquitous in both aquatic and terrestrial ecosystem. Breathing, ingestion, consumption of food stuffs, potable water, and skin are possible routes of MP exposure that pose potential human health risk. Various microorganisms including bacteria, cyanobacteria, and microalgae rapidly colonized on MP surfaces which initiate biofilm formation. It gradually changed the MP surface chemistry and polymer properties that attract environmental metals. Physicochemical and environmental parameters like polymer type, dissolved organic matter (DOM), pH, salinity, ion concentrations, and microbial community compositions regulate metal adsorption on MP biofilm surface. A set of highly conserved proteins tightly regulates metal uptake, subcellular distribution, storage, and transport to maintain cellular homeostasis. Exposure of metal-MP biofilm can disrupt that cellular homeostasis to induce toxicities. Imbalances in metal concentrations therefore led to neuronal network dysfunction, ROS, mitochondrial damage in diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and Prion disorder. This review focuses on the biofilm development on MP surfaces, factors controlling the growth of MP biofilm which triggered metal accumulation to induce neurotoxicological consequences in human body and stategies to reestablish the homeostasis. Thus, the present study gives a new approach on the health risks of heavy metals associated with MP biofilm in which biofilms trigger metal accumulation and MPs serve as a vector for those accumulated metals causing metal dysbiosis in human body.}, } @article {pmid37781531, year = {2023}, author = {Jimoh, AA and Booysen, E and van Zyl, L and Trindade, M}, title = {Do biosurfactants as anti-biofilm agents have a future in industrial water systems?.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1244595}, pmid = {37781531}, issn = {2296-4185}, abstract = {Biofilms are bacterial communities embedded in exopolymeric substances that form on the surfaces of both man-made and natural structures. Biofilm formation in industrial water systems such as cooling towers results in biofouling and biocorrosion and poses a major health concern as well as an economic burden. Traditionally, biofilms in industrial water systems are treated with alternating doses of oxidizing and non-oxidizing biocides, but as resistance increases, higher biocide concentrations are needed. Using chemically synthesized surfactants in combination with biocides is also not a new idea; however, these surfactants are often not biodegradable and lead to accumulation in natural water reservoirs. Biosurfactants have become an essential bioeconomy product for diverse applications; however, reports of their use in combating biofilm-related problems in water management systems is limited to only a few studies. Biosurfactants are powerful anti-biofilm agents and can act as biocides as well as biodispersants. In laboratory settings, the efficacy of biosurfactants as anti-biofilm agents can range between 26% and 99.8%. For example, long-chain rhamnolipids isolated from Burkholderia thailandensis inhibit biofilm formation between 50% and 90%, while a lipopeptide biosurfactant from Bacillus amyloliquefaciens was able to inhibit biofilms up to 96% and 99%. Additionally, biosurfactants can disperse preformed biofilms up to 95.9%. The efficacy of antibiotics can also be increased by between 25% and 50% when combined with biosurfactants, as seen for the V9T14 biosurfactant co-formulated with ampicillin, cefazolin, and tobramycin. In this review, we discuss how biofilms are formed and if biosurfactants, as anti-biofilm agents, have a future in industrial water systems. We then summarize the reported mode of action for biosurfactant molecules and their functionality as biofilm dispersal agents. Finally, we highlight the application of biosurfactants in industrial water systems as anti-fouling and anti-corrosion agents.}, } @article {pmid37781057, year = {2023}, author = {Yum, SJ and Jeong, HG and Kim, SM}, title = {Correction: Anti‑biofilm effects of sinomenine against Staphylococcus aureus.}, journal = {Food science and biotechnology}, volume = {32}, number = {13}, pages = {1955}, doi = {10.1007/s10068-022-01187-9}, pmid = {37781057}, issn = {2092-6456}, abstract = {[This corrects the article DOI: 10.1007/s10068-022-01174-0.].}, } @article {pmid37781014, year = {2023}, author = {Gomes, T and Ribeiro, PS and Carvalho, NB and El-Hani, CN and Figueira, CP and Ristow, P}, title = {Impact of Extracellular DNA on Architectural Parameters of Leptospira biflexa Biofilm.}, journal = {Indian journal of microbiology}, volume = {63}, number = {3}, pages = {373-379}, pmid = {37781014}, issn = {0046-8991}, abstract = {Extracellular DNA (eDNA) is a major component of bacterial biofilms. In this study, we performed a three-dimensional analysis of Leptospira biofilm using advanced imaging by confocal laser scanning microscopy (CLSM) and multi-parameter analysis by COMSTAT 2 software, with quantification of Leptospira and eDNA fluorescence. To investigate the role of eDNA in Leptospira biofilm, we treated Leptospira biflexa biofilms with DNase I enzyme (DNase), which digested eDNA, and compared DNase treated biofilms and controls. There was a significant reduction of the biomass of biofilms treated with DNase, by spectrophotometry and COMSTAT analysis. The multiparameter analysis evidenced for DNase-treated biofilms a significant decrease in the surface area and the average thickness; opposing to a significant augmentation of the surface/biovolume ratio and the roughness coefficient (Ra*), when compared to controls. We analyzed the parameters of DNase-treated biofilms by Pearson's correlation coefficient and found significant positive correlations between biomass and average thickness; biomass and surface area; surface area and average thickness. On the other hand, there were significant negative correlations between Ra* and biomass; Ra* and average thickness; Ra* and surface area. These findings suggest that eDNA digestion results in biofilm instability and alteration of the three-dimensional architecture, justifying the negative correlation between Ra* and the above-mentioned parameters. In conclusion, our study showed that eDNA digestion produced a massive structural loss, instability, and dramatic changes in the three-dimensional architecture of Leptospira biflexa biofilm. These findings contribute to a better understanding of the role of eDNA and highlight the importance of eDNA as a key component in Leptospira biofilms.}, } @article {pmid37781013, year = {2023}, author = {Rana, S and Upadhyay, LSB}, title = {Methylene Blue Assisted Electrochemical Detection of Bacterial Biofilm.}, journal = {Indian journal of microbiology}, volume = {63}, number = {3}, pages = {299-306}, pmid = {37781013}, issn = {0046-8991}, abstract = {This paper presents a novel electrochemical transduction method for the rapid and straightforward detection of bacterial biofilm. Briefly, fifteen isolates from various sources were collected and evaluated for their ability to generate biofilm. The Congo red-based agar method and the tube test were used for preliminary screening. A microtiter experiment was also performed to quantitatively examine the screening results and validate the outcomes of the proposed methylene blue-based electrochemical detection method. Electrochemical sensing was performed on the two selected isolates using methylene blue as a redox indicator. For optimization goals, several methylene blue concentrations were studied. Methylene blue at a concentration of 0.4 mM was used for the analysis conclusion. The developed electrochemical method displayed a linear R[2] value of 0.9747. The new electrochemical approach demonstrated great sensitivity and rapid response compared to conventional microtiter test methods.}, } @article {pmid37780599, year = {2023}, author = {Byun, KH and Kim, HJ}, title = {Survival strategies of Listeria monocytogenes to environmental hostile stress: biofilm formation and stress responses.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1631-1651}, pmid = {37780599}, issn = {2092-6456}, abstract = {Listeria monocytogenes is a critical foodborne pathogen that causes listeriosis and threatens public health. This pathogenic microorganism forms a transmission cycle in nature, food industry, and humans, expanding the areas of contamination among them and influencing food safety. L. monocytogenes forms biofilms to protect itself and promotes survival through stress responses to the various stresses (e.g., temperature, pH, and antimicrobial agents) that may be inflicted during food processing. Biofilms and mechanisms of resistance to hostile external or general stresses allow L. monocytogenes to survive despite a variety of efforts to ensure food safety. The current review article focuses on biofilm formation, resistance mechanisms through biofilms, and external specific or general stress responses of L. monocytogenes to help understand the unexpected survival rates of this bacterium; it also proposes the use of obstacle technology to effectively cope with it in the food industry.}, } @article {pmid37780598, year = {2023}, author = {Han, A and Lee, SY}, title = {An overview of various methods for in vitro biofilm formation: a review.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1617-1629}, pmid = {37780598}, issn = {2092-6456}, abstract = {Biofilms are widely present in the natural environment and are difficult to remove as they are a survival strategy of microorganisms. Thus, the importance of studying biofilms is being increasingly recognized in food, medical, dental, and water quality-related industries. While research on biofilm detection methods is actively progressing, research on biofilm formation is not progressing rapidly. Moreover, there are few standardized methods because biofilm formation is affected by various factors. However, comprehensive knowledge of biofilm formation is essential to select a suitable method for research purposes. To better understand the various in vitro biofilm formation methods, the principles and characteristics of each method are explained in this review by dividing the methods into static and dynamic systems. In addition, the applications of biofilm research based on various assays are also discussed.}, } @article {pmid37780597, year = {2023}, author = {Kim, U and Lee, SY and Oh, SW}, title = {A review of mechanism analysis methods in multi-species biofilm of foodborne pathogens.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1665-1677}, pmid = {37780597}, issn = {2092-6456}, abstract = {Biofilms are an aggregation of microorganisms that have high resistance to antimicrobial agents. In the food industry, it has been widely studied that foodborne pathogens on both food surfaces and food-contact surfaces can form biofilms thereby threatening the safety of the food. In the natural environment, multi-species biofilms formed by more than two different microorganisms are abundant. In addition, the resistance of multi-species biofilms to antimicrobial agents is higher than that of mono-species biofilms. Therefore, studies to elucidate the mechanisms of multi-species biofilms formed by foodborne pathogens are still required in the food industry. In this review paper, we summarized the novel analytical methods studied to evaluate the mechanisms of multi-species biofilms formed by foodborne pathogens by dividing them into four categories: spatial distribution, bacterial interaction, extracellular polymeric substance production and quorum sensing analytical methods.}, } @article {pmid37780596, year = {2023}, author = {Pang, X and Hu, X and Du, X and Lv, C and Yuk, HG}, title = {Biofilm formation in food processing plants and novel control strategies to combat resistant biofilms: the case of Salmonella spp.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1703-1718}, pmid = {37780596}, issn = {2092-6456}, abstract = {Salmonella is one of the pathogens that cause many foodborne outbreaks throughout the world, representing an important global public health problem. Salmonella strains with biofilm-forming abilities have been frequently isolated from different food processing plants, especially in poultry industry. Biofilm formation of Salmonella on various surfaces can increase their viability, contributing to their persistence in food processing environments and cross-contamination of food products. In recent years, increasing concerns arise about the antimicrobial resistant and disinfectant tolerant Salmonella, while adaptation of Salmonella in biofilms to disinfectants exacerbate this problem. Facing difficulties to inhibit or remove Salmonella biofilms in food industry, eco-friendly and effective strategies based on chemical, biotechnological and physical methods are in urgent need. This review discusses biofilm formation of Salmonella in food industries, with emphasis on the current available knowledge related to antimicrobial resistance, together with an overview of promising antibiofilm strategies for controlling Salmonella in food production environments.}, } @article {pmid37780595, year = {2023}, author = {Kim, JS and Lim, MC and Kim, SM and Lee, JY}, title = {Extracellular matrix-degrading enzymes as a biofilm control strategy for food-related microorganisms.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1745-1761}, pmid = {37780595}, issn = {2092-6456}, abstract = {Biofilm is one of the major problems in food industries and is difficult to be removed or prevented by conventional sanitizers. In this review, we discussed the extracellular matrix-degrading enzymes as a strategy to control biofilms of foodborne pathogenic and food-contaminating bacteria. The biofilms can be degraded by using the enzymes targeting proteins, polysaccharides, extracellular DNA, or lipids which mainly constitute the extracellular polymeric substances of biofilms. However, the efficacy of enzymes varies by the growth medium, bacterial species, strains, or counterpart microorganisms due to a high variation in the composition of extracellular polymeric substances. Several studies demonstrated that the combined treatment using conventional sanitizers or multiple enzymes can synergistically enhance the biofilm removal efficacies. In this review, the application of the immobilized enzymes on solid substrates is also discussed as a potential strategy to prevent biofilm formation on food contact surfaces.}, } @article {pmid37780594, year = {2023}, author = {Cevallos-Urena, A and Kim, JY and Kim, BS}, title = {Vibrio-infecting bacteriophages and their potential to control biofilm.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1719-1727}, pmid = {37780594}, issn = {2092-6456}, abstract = {The emergence and spread of antibiotic-resistant pathogenic bacteria have necessitated finding new control alternatives. Under these circumstances, lytic bacteriophages offer a viable and promising option. This review focuses on Vibrio-infecting bacteriophages and the characteristics that make them suitable for application in the food and aquaculture industries. Bacteria, particularly Vibrio spp., can produce biofilms under stress conditions. Therefore, this review summarizes several anti-biofilm mechanisms that phages have, such as stimulating the host bacteria to produce biofilm-degrading enzymes, utilizing tail depolymerases, and penetrating matured biofilms through water channels. Additionally, the advantages of bacteriophages over antibiotics, such as a lower probability of developing resistance and the ability to infect dormant cells, are discussed. Finally, this review presents future research prospects related to further utilization of phages in diverse fields.}, } @article {pmid37780592, year = {2023}, author = {Ban, GH and Kim, SH and Kang, DH and Park, SH}, title = {Comparison of the efficacy of physical and chemical strategies for the inactivation of biofilm cells of foodborne pathogens.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1679-1702}, pmid = {37780592}, issn = {2092-6456}, abstract = {Biofilm formation is a strategy in which microorganisms generate a matrix of extracellular polymeric substances to increase survival under harsh conditions. The efficacy of sanitization processes is lowered when biofilms form, in particular on industrial devices. While various traditional and emerging technologies have been explored for the eradication of biofilms, cell resistance under a range of environmental conditions renders evaluation of the efficacy of control challenging. This review aimed to: (1) classify biofilm control measures into chemical, physical, and combination methods, (2) discuss mechanisms underlying inactivation by each method, and (3) summarize the reduction of biofilm cells after each treatment. The review is expected to be useful for future experimental studies and help to guide the establishment of biofilm control strategies in the food industry.}, } @article {pmid37780591, year = {2023}, author = {Mun, W and Choi, SY and Upatissa, S and Mitchell, RJ}, title = {Predatory bacteria as potential biofilm control and eradication agents in the food industry.}, journal = {Food science and biotechnology}, volume = {32}, number = {12}, pages = {1729-1743}, pmid = {37780591}, issn = {2092-6456}, abstract = {Biofilms are a major concern within the food industry since they have the potential to reduce productivity in situ (within the field), impact food stability and storage, and cause downstream food poisoning. Within this review, predatory bacteria as potential biofilm control and eradication agents are discussed, with a particular emphasis on the intraperiplasmic Bdellovibrio-and-like organism (BALO) grouping. After providing a brief overview of predatory bacteria and their activities, focus is given to how BALOs fulfill four attributes that are essential for biocontrol agents to be successful in the food industry: (1) Broad spectrum activity against pathogens, both plant and human; (2) Activity against biofilms; (3) Safety towards humans and animals; and (4) Compatibility with food. As predatory bacteria possess all of these characteristics, they represent a novel form of biofilm biocontrol that is ripe for use within the food industry.}, } @article {pmid37780020, year = {2023}, author = {Abu Ghazal, TS and Veres, K and Vidács, L and Szemerédi, N and Spengler, G and Berkecz, R and Hohmann, J}, title = {Furanonaphthoquinones, Diterpenes, and Flavonoids from Sweet Marjoram and Investigation of Antimicrobial, Bacterial Efflux, and Biofilm Formation Inhibitory Activities.}, journal = {ACS omega}, volume = {8}, number = {38}, pages = {34816-34825}, pmid = {37780020}, issn = {2470-1343}, abstract = {The chloroform extract of Origanum majorana exhibited high antibacterial and antifungal activities against 12 bacterial and 4 fungal strains; therefore, it was subjected to bioassay-guided isolation to afford six compounds (1-6). The structures were determined via one- and two-dimensional nuclear magnetic spectroscopy and high-resolution electrospray ionization mass spectrometry experiments. The compounds were identified as furanonaphthoquinones [majoranaquinone (1), 2,3-dimethylnaphtho[2,3-b]furan-4,9-dione (2)], diterpenes [19-hydroxyabieta-8,11,13-trien-7-one (3), 13,14-seco-13-oxo-19-hydroxyabieta-8-en-14-al (4)], and flavonoids [sterubin (5) and majoranin (6)]. Compounds 1 and 2 were first obtained from a natural source and compounds 3 and 4 were previously undescribed. Majoranaquinone (1) exhibited a high antibacterial effect against 4 Staphylococcus, 1 Moraxella, and 1 Enterococcus strains (MIC values between 7.8 μM and 1 mM). In the efflux pump inhibition assay, majoranaquinone (1) showed substantial activity in Escherichia coli ATCC 25922 strain. Furthermore, 1 was found to be an effective biofilm formation inhibitor on E. coli ATCC 25922 and E. coli K-12 AG100 bacteria. Our findings proved that bioactivities of majoranaquinone (1) significantly exceed those of the essential oil constituents; therefore, it should also be considered when assessing the antimicrobial effects of O. majorana.}, } @article {pmid37779859, year = {2023}, author = {Liu, J and Huang, T and Xu, Z and Mao, Y and Soteyome, T and Liu, G and Qu, C and Yuan, L and Ma, Q and Zhou, F and Seneviratne, G}, title = {Sub-MIC streptomycin and tetracycline enhanced Staphylococcus aureus Guangzhou-SAU749 biofilm formation, an in-depth study on transcriptomics.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100156}, pmid = {37779859}, issn = {2590-2075}, abstract = {Staphylococcus aureus is a major human pathogen, a potential "Super-bug" and a typical biofilm forming bacteria. With usage of large amount of antibiotics, the residual antibiotics in clinical settings further complicate the colonization, pathogenesis and resistance of S. aureus. This study aimed at investigating the phenotypical and global gene expression changes on biofilm formation of a clinical S. aureus isolate treated under different types of antibiotics. Firstly, an isolate Guangzhou-SAU749 was selected from a large sale of previously identified S. aureus isolates, which exhibited weak biofilm formation in terms of biomass and viability. Secondly, 9 commonly prescribed antibiotics for S. aureus infections treatment, together with 10 concentrations ranging from 1/128 to 4 minimum inhibitory concentration (MIC) with 2-fold serial dilution, were used as different antibiotic stress conditions. Then, biofilm formation of S. aureus Guangzhou-SAU749 at different stages including 8 h, 16 h, 24 h, and 48 h, was tested by crystal violet and MTS assays. Thirdly, the whole genome of S. aureus Guangzhou-SAU749 was investigated by genome sequencing on PacBio platform. Fourthly, since enhancement of biofilm formation occurred when treated with 1/2 MIC tetracycline (TCY) and 1/4 MIC streptomycin (STR) since 5 h, the relevant biofilm samples were selected and subjected to RNA-seq and bioinformatics analysis. Last, expression of two component system (TCS) and biofilm associated genes in 4 h, 8 h, 16 h, 24 h, and 48 h sub-MIC TCY and STR treated biofilm samples were performed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Although most antibiotics lowered the biomass and cell viability of Guangzhou-SAU749 biofilm at concentrations higher than MIC, certain antibiotics including TCY and STR promoted biofilm formation at sub-MICs. Additionally, upon genome sequencing, RNA-seq and RT-qPCR on biofilm samples treated with sub-MIC of TCY and STR at key time points, genes lytR, arlR, hssR, tagA, clfB, atlA and cidA related to TCS and biofilm formation were identified to contribute to the enhanced biofilm formation, providing a theoretical basis for further controlling on S. aureus biofilm formation.}, } @article {pmid37779401, year = {2023}, author = {Pakzad, I and Yarkarami, F and Kalani, BS and Shafieian, M and Hematian, A}, title = {Inhibitory Effects of Carvacrol on Biofilm Formation in Colistin Heteroresistant Acinetobacter baumannii Clinical Isolates.}, journal = {Current drug discovery technologies}, volume = {}, number = {}, pages = {}, doi = {10.2174/0115701638253395230919112548}, pmid = {37779401}, issn = {1875-6220}, abstract = {BACKGROUND: The ability of bacteria to form biofilm is an essential strategy for creating stable infections. This issue is more critical in Acinetobacter bauamannii as a hospital pathogen. Today, the control of biofilm formation and solutions to prevent or remove biofilm is being developed. Carvacrol has been considered an anti-biofilm compound in significant bacteria. This study investigated the anti-biofilm effect of Carvacrol on biofilm formation in clinical colistin heteroresistant isolates of A. baumannii.

METHODS: About 22 clinical strains of A. baumannii were collected from Motahari Hospital in Tehran, Iran, in 2019. Biochemical and genotypic methods confirmed these isolates. Colistin heteroresistance was determined by the Standard PAP method. Carvacrol's antibacterial and anti-biofilm activity was determined according to the standard protocol.

RESULTS: About 12 isolates were considered strong biofilm producers and were used for analysis. Six isolates had hetero-resistance to colistin. Carvacrol at a 512 g/ml concentration showed the best antibacterial activity against all isolates. The sub-MIC of Carvacrol (256 g/ml) reduced the biofilm formation capacity, which was statistically significant (p<0.05).

CONCLUSION: The results of this study showed that sub-MIC of Carvacrol has anti-biofilm effects in clinical A.baumannii colistin hetero-resistance isolates.}, } @article {pmid37779331, year = {2023}, author = {Febria, FA and Zulkhairiah, F and Walpajri, F and Putra, A and Syukriani, L}, title = {Biofilm-Forming Heavy Metal Resistance Bacteria From Bungus Ocean Fisheries Port (PPS) West Sumatra as a Waters Bioremediation Agent.}, journal = {Pakistan journal of biological sciences : PJBS}, volume = {26}, number = {4}, pages = {168-176}, doi = {10.3923/pjbs.2023.168.176}, pmid = {37779331}, issn = {1812-5735}, abstract = {Background and Objective: Heavy metals are one of the most worrisome pollutants due to their toxicity. Prolonged exposure to heavy metals and their accumulation and biomagnification properties adversely affect aquatic biota and human health. The ability of microorganisms to bioremediate heavy metals into non-toxic forms is one solution. The research aims of the study were to find biofilm-forming heavy metal-resistant bacteria isolated from the waters of the Bungus Samudra Fishery Port (PPS), Padang City. Materials and Methods: This study used a marine agar medium modified with the addition of K2Cr2O7, Pb(NO3)2 and CdSO4•H2O, Marine Broth medium and Congo Red Agar medium. The research methods include, the isolation of bacteria, isolate resistance test to heavy metals, testing the ability of isolates to form biofilms and determine the ability of isolates to reduce heavy metals. Furthermore, molecular identification of bacterial isolates was carried out to determine the type of species. Results: Five heavy metal-resistant bacterial isolates were found that were able to form biofilms, namely isolates B3Cd, B5Cr, B7Pb, B6Pb and B3Pb. The five isolates were able to reduce heavy metal content by 38.67-61.191%. Identification of the best bacterial isolates on each heavy metal tested, namely B3Cd, B5Cr and B7Pb, respectively, showed the type of Acinetobacter schindleri, Acinetobacter sp. and Bacillus sp. Conclusion: These three selected potential isolates can be used as bioremediation agents in metal-polluted waters in the future.}, } @article {pmid37778576, year = {2023}, author = {Datki, Z and Darula, Z and Vedelek, V and Hunyadi-Gulyas, E and Dingmann, BJ and Vedelek, B and Kalman, J and Urban, P and Gyenesei, A and Galik-Olah, Z and Galik, B and Sinka, R}, title = {Biofilm formation initiating rotifer-specific biopolymer and its predicted components.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127157}, doi = {10.1016/j.ijbiomac.2023.127157}, pmid = {37778576}, issn = {1879-0003}, abstract = {The rotifer-specific biopolymer, namely Rotimer, is a recently discovered group of the biomolecule family. Rotimer has an active role in the biofilm formation initiated by rotifers (e.g., Euchlanis dilatata or Adineta vaga) or in the female-male sexual interaction of monogononts. To understand the Ca[2+]- and polarity-dependent formation of this multifunctional viscoelastic material, it is essential to explore its molecular composition. The investigation of the rotifer-enhanced biofilm and Rotimer-inductor conglomerate (RIC) formation yielded several protein candidates to predict the Rotimer-specific main components. The exudate of E. dilatata males was primarily applied from different biopolimer-containing samples (biofilm or RIC). The advantage of males over females lies in their degenerated digestive system and simple anatomy. Thus, their exudate is less contaminated with food and endosymbiont elements. The sequenced and annotated genome and transcriptome of this species opened the way for identifying Rotimer proteins by mass spectrometry. The predicted rotifer-biopolymer forming components are SCO-spondins and 14-3-3 protein. The characteristics of Rotimer are similar to Reissner's fiber, which is found in the central nervous system of vertebrates and is mainly formed from SCO-spondins. This molecular information serves as a starting point for its interdisciplinary investigation and application in biotechnology, biomedicine, or neurodegeneration-related drug development.}, } @article {pmid37776833, year = {2023}, author = {Basiri, N and Zarei, M and Kargar, M and Kafilzadeh, F}, title = {Effect of plasma-activated water on the biofilm-forming ability of Salmonella enterica serovar Enteritidis and expression of the related genes.}, journal = {International journal of food microbiology}, volume = {406}, number = {}, pages = {110419}, doi = {10.1016/j.ijfoodmicro.2023.110419}, pmid = {37776833}, issn = {1879-3460}, abstract = {In recent years, microbial decontamination with plasma-activated water (PAW) has attracted a lot of research attention in the field of food industry. Despite several studies showing that PAW effectively inactivates planktonic bacteria, few studies have been conducted on biofilms. The present study was, therefore, designed to evaluate the effect of PAW on the biofilm formation characteristics of Salmonella Enteritidis. Comparing the expression patterns of biofilm-related genes in PAW-treated and non-treated planktonic and biofilm cells provided insight into how PAW regulates this process. The results showed that a 30-minute exposure to PAW at room temperature significantly reduced S. enteritidis planktonic cells. This exposure resulted in a decreased expression of the genes involved in the early stages of biofilm formation (csgD, agfA, fimA, lpfE, and rpoS), and an increased expression of the csrA gene in S. enteritidis planktonic cells. These results indicated the inhibitory effect of PAW on the biofilm formation process in S. enteritidis. Results of the initial attachment assay confirmed these findings, where, after 6 h, the number of PAW-treated cells attached to the stainless steel surfaces were significantly lower than non-treated ones. Furthermore, biofilm development assay revealed that the number of PAW-treated biofilm cells were significantly lower than non-treated ones after 24 h incubation at 37 °C. These findings were confirmed by measurements of the major components of biofilm i.e., extracellular DNA (eDNA), protein and carbohydrate. The amount of these components in 24-hour biofilms produced by PAW-treated S. enteritidis cells was significantly lower than that of non-treated cells. PAW's treatment on preformed 24-hour biofilms for 30 min led to a decrease in the expression of genes involved in quorum sensing and cellulose synthesis (csgD, bapA, adrA, luxS and sdiA) and an increase in the expression of the csrA gene. This treatment also reduced the number and metabolic activity of biofilm cells compared to non-treated biofilm cells. In total, the present study demonstrated that PAW has an inhibitory effect on the process of biofilm formation in S. enteritidis and hence, the food industry should pay special attention to PAW as a promising treatment to eliminate bacterial biofilms.}, } @article {pmid37776579, year = {2023}, author = {Scribani Rossi, C and Eckartt, K and Scarchilli, E and Angeli, S and Price-Whelan, A and Di Matteo, A and Chevreuil, M and Raynal, B and Arcovito, A and Giacon, N and Fiorentino, F and Rotili, D and Mai, A and Espinosa-Urgel, M and Cutruzzolà, F and Dietrich, LEP and Paone, A and Paiardini, A and Rinaldo, S}, title = {Molecular insights into RmcA-mediated c-di-GMP consumption: Linking redox potential to biofilm morphogenesis in Pseudomonas aeruginosa.}, journal = {Microbiological research}, volume = {277}, number = {}, pages = {127498}, doi = {10.1016/j.micres.2023.127498}, pmid = {37776579}, issn = {1618-0623}, abstract = {The ability of many bacteria to form biofilms contributes to their resilience and makes infections more difficult to treat. Biofilm growth leads to the formation of internal oxygen gradients, creating hypoxic subzones where cellular reducing power accumulates, and metabolic activities can be limited. The pathogen Pseudomonas aeruginosa counteracts the redox imbalance in the hypoxic biofilm subzones by producing redox-active electron shuttles (phenazines) and by secreting extracellular matrix, leading to an increased surface area-to-volume ratio, which favors gas exchange. Matrix production is regulated by the second messenger bis-(3',5')-cyclic-dimeric-guanosine monophosphate (c-di-GMP) in response to different environmental cues. RmcA (Redox modulator of c-di-GMP) from P. aeruginosa is a multidomain phosphodiesterase (PDE) that modulates c-di-GMP levels in response to phenazine availability. RmcA can also sense the fermentable carbon source arginine via a periplasmic domain, which is linked via a transmembrane domain to four cytoplasmic Per-Arnt-Sim (PAS) domains followed by a diguanylate cyclase (DGC) and a PDE domain. The biochemical characterization of the cytoplasmic portion of RmcA reported in this work shows that the PAS domain adjacent to the catalytic domain tunes RmcA PDE activity in a redox-dependent manner, by differentially controlling protein conformation in response to FAD or FADH2. This redox-dependent mechanism likely links the redox state of phenazines (via FAD/FADH2 ratio) to matrix production as indicated by a hyperwrinkling phenotype in a macrocolony biofilm assay. This study provides insights into the role of RmcA in transducing cellular redox information into a structural response of the biofilm at the population level. Conditions of resource (i.e. oxygen and nutrient) limitation arise during chronic infection, affecting the cellular redox state and promoting antibiotic tolerance. An understanding of the molecular linkages between condition sensing and biofilm structure is therefore of crucial importance from both biological and engineering standpoints.}, } @article {pmid37776076, year = {2023}, author = {Oliver, C and Ruiz, P and Vidal, JM and Carrasco, C and Escalona, CE and Barros, J and Sepúlveda, D and Urrutia, H and Romero, A}, title = {Effect of florfenicol on Piscirickettsia salmonis biofilm formed in materials used in salmonid nets, nylon and high-density polyethylene.}, journal = {Journal of fish diseases}, volume = {}, number = {}, pages = {}, doi = {10.1111/jfd.13862}, pmid = {37776076}, issn = {1365-2761}, support = {//Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias/ ; //Fondo Nacional de Desarrollo Científico y Tecnológico/ ; }, abstract = {Piscirickettsiosis is the most prevalent bacterial disease affecting seawater salmon in Chilean salmon industry. Antibiotic therapy is the first alternative to counteract infections caused by Piscirickettsia salmonis. The presence of bacterial biofilms on materials commonly used in salmon farming may be critical for understanding the bacterial persistence in the environment. In the present study, the CDC Biofilm Reactor® was used to investigate the effect of sub- and over-MIC of florfenicol on both the pre-formed biofilm and the biofilm formation by P. salmonis under the antibiotic stimuli on Nylon and high-density polyethylene (HDPE) surfaces. This study demonstrated that FLO, at sub- and over-MIC doses, decreases biofilm-embedded live bacteria in the P. salmonis isolates evaluated. However, it was shown that in the P. salmonis Ps007 strain the presence of sub-MIC of FLO reduced its biofilm formation on HDPE surfaces; however, biofilm persists on Nylon surfaces. These results demonstrated that P. salmonis isolates behave differently against FLO and also, depending on the surface materials. Therefore, it remains a challenge to find an effective strategy to control the biofilm formation of P. salmonis, and certainly other marine pathogens that affect the sustainability of the Chilean salmon industry.}, } @article {pmid37775527, year = {2023}, author = {Subramani, RM and Lotha, R and Shamprasad, BR and Sridharan, S and Natesan, R and Nagarajan, S and Sivasubramanian, A}, title = {BBD optimized antioxidants of Crotalaria candicans and its nanoconjugates, exert potent in vivo anti-biofilm effects against MRSA.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {16407}, pmid = {37775527}, issn = {2045-2322}, support = {CRG/2020/001063//Science and Engineering Research Board/ ; CRG/2020/001063//Science and Engineering Research Board/ ; CRG/2020/001063//Science and Engineering Research Board/ ; CRG/2020/001063//Science and Engineering Research Board/ ; SR/FST/CS-I/2018/62//DST-FIST/ ; SR/FST/CS-I/2018/62//DST-FIST/ ; SR/FST/CS-I/2018/62//DST-FIST/ ; SR/FST/CS-I/2018/62//DST-FIST/ ; }, abstract = {Crotalaria genus is extensively dispersed in tropical and subtropical provinces, and it is found to harbor antioxidant flavonoids. Response surface methodology-based optimization was carried out for the purpose of efficient extraction involving a suitable solvent which can maximize the yield along with higher total phenolic content and total flavonoid content (TFC). Optimization conditions for extraction of C.candicans flavonoids (CCF) based on variables such as solvent, solid-solvent ratio and extraction temperature were evaluated. The optimized conditions were found as Solvent i.e., Aqueous-ethanol (53.42%), Solid-solvent ratio (1:15.83 w/v) and temperature (44.42 °C) and resulted to obtain the TFC as 176.23 mg QRET/g C. candicans extract with the yield 27.42 mg CCF/g (C. candicans dry weight). LC-MS analysis of CCF, revealed the presence of seven major flavonoids. The antioxidant flavonoids were further used to functionalize the zero-valent silver (ZVAgF) and copper (ZVCuF) nanoparticles. The ZVAgF and ZVCuF were investigated using UV-Vis spectrophotometry, FT-IR spectroscopy and X-ray diffractometry to confirm the presence of the zero valent metals and possible functional groups which capped the elemental metal. Further transmission electron microscopy, dynamic light scattering method and zeta-potential studies were done to understand their respective structural and morphological properties. The efficacy of the as-prepared ZVAgF/ZVCuF as antibiofilm agents on Methicillin-resistant Staphylococcus aureus (MRSA) with the mechanism studies have been explored. The MRSA-colony count from the infection zebrafish (in vivo) model, portrayed a reduction of > 1.9 fold for ZVCuF and > twofold for ZVAgF, with no alteration in liver morphology when treated with ZVAgF, implying that the nanoparticles were safe and biocompatible.}, } @article {pmid37775770, year = {2023}, author = {Deilamani, MO and Nikkhahi, F and Bakht, M and Ali Alizadeh, S and Fardsanei, F and Javadi, A and Marashi, SMA and Aslanimehr, M and Peymani, A}, title = {Evaluation of ethanol and EDTA concentrations in the expression of biofilm-producing smf-1, rpfF genes in XDR clinical isolates of Stenotrophomonas maltophilia.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {277}, pmid = {37775770}, issn = {1471-2180}, abstract = {BACKGROUND: Stenotrophomonas maltophilia is able to cause infections in immunocompromised patients, and the treatment of this opportunistic pathogen is complicated due to its virulence factors, antibiotic resistance, and the ability of the bacteria to produce biofilm. The main goals of this study were to assess the susceptibility of extensively drug-resistant (XDR) isolates to ethanol and EDTA, and evaluating the synergistic effect of these disinfectants, and also survey the effect of exposure to sub-inhibitory concentrations of ethanol and EDTA on the expression of biofilm-producing smf-1, rpfF genes.

RESULTS: The results showed that EDTA significantly increased the effectiveness of the ethanol and have a synergistic effect. All of the 10 XDR isolates included in the current study harbored smf-1 and rpfF genes and produced biofilm. After exposure to MIC, sub-MIC, synergism, and sub-synergism of ethanol and EDTA, the expression of smf-1 and rpfF genes was repressed significantly.

CONCLUSION: In the current study, it was indicated that the expression of biofilm-producing genes was repressed when bacteria are exposed to different concentrations of ethanol and EDTA. Future studies should include more complex microbial communities residing in the hospitals, and more disinfectants use in hospitals. Expression of other virulence genes in different conditions is suggested.}, } @article {pmid37774161, year = {2023}, author = {Van Wicklin, SA}, title = {Biofilm.}, journal = {Plastic and aesthetic nursing}, volume = {43}, number = {4}, pages = {170-173}, pmid = {37774161}, issn = {2770-3517}, } @article {pmid37773239, year = {2023}, author = {Huang, Y and Liu, Y and Pandey, NK and Shah, S and Simon-Soro, A and Hsu, JC and Ren, Z and Xiang, Z and Kim, D and Ito, T and Oh, MJ and Buckley, C and Alawi, F and Li, Y and Smeets, PJM and Boyer, S and Zhao, X and Joester, D and Zero, DT and Cormode, DP and Koo, H}, title = {Iron oxide nanozymes stabilize stannous fluoride for targeted biofilm killing and synergistic oral disease prevention.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {6087}, pmid = {37773239}, issn = {2041-1723}, abstract = {Dental caries is the most common human disease caused by oral biofilms despite the widespread use of fluoride as the primary anticaries agent. Recently, an FDA-approved iron oxide nanoparticle (ferumoxytol, Fer) has shown to kill and degrade caries-causing biofilms through catalytic activation of hydrogen peroxide. However, Fer cannot interfere with enamel acid demineralization. Here, we show notable synergy when Fer is combined with stannous fluoride (SnF2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, we discover that the stability of SnF2 is enhanced when mixed with Fer in aqueous solutions while increasing catalytic activity of Fer without any additives. Notably, Fer in combination with SnF2 is exceptionally effective in controlling dental caries in vivo, even at four times lower concentrations, without adverse effects on host tissues or oral microbiome. Our results reveal a potent therapeutic synergism using approved agents while providing facile SnF2 stabilization, to prevent a widespread oral disease with reduced fluoride exposure.}, } @article {pmid37772319, year = {2023}, author = {Liu, L and Chen, X and Zhang, C and Deng, J and Xiao, H and Rao, Y}, title = {Lactiplantibacillus biofilm and planktonic cells ameliorate ulcerative colitis in mice via immunoregulatory activity, gut metabolism and microbiota modulation.}, journal = {Food & function}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3fo02733c}, pmid = {37772319}, issn = {2042-650X}, abstract = {Since ulcerative colitis (UC) has become a global concern, Lactiplantibacillus is considered an effective, safe strategy for alleviating intestinal inflammation in UC patients. The most advanced fourth-generation probiotics involve beneficial bacteria enclosed in biofilms with multiple advantages. However, the difference between the effect of probiotic biofilm and planktonic cells on UC remains unclear. This study indicated that the biofilm cells of Lactiplantibacillus LR-1 were more successful in increasing the colon length, relieving intestinal inflammation, and repairing colon damage, regulating the host immunity than the planktonic cells. Furthermore, the LR-1 biofilm cells helped prevent a decline in the Eubacterium hallii and Salinimicrobium levels and increased Kocuria and Candidatus Bacilloplasma abundance. Untargeted metabolomics analysis results suggested that the LR-1 biofilm was more successful in promoting the intestinal metabolism recovery of the UC mice than the planktonic cells. Finally, the phenotype-microbiota-metabolism network was conducted to reveal the relationship between these factors.}, } @article {pmid37771524, year = {2023}, author = {Chan, H and Pavelka, MS and Baran, TM}, title = {Methylene blue photodynamic therapy of bacterial species found in human abscesses: Planktonic, biofilm, and 3D silicone models.}, journal = {Proceedings of SPIE--the International Society for Optical Engineering}, volume = {12358}, number = {}, pages = {}, pmid = {37771524}, issn = {0277-786X}, abstract = {Deep tissue abscesses are inflammatory, purulent lesions encased in a fibrin-rich pseudocapsule that include multiple bacterial and fungal species. We have initiated a Phase 1 clinical trial exploring the safety and feasibility of methylene blue photodynamic therapy (MB-PDT) at the time of abscess drainage. To optimize treatment parameters for future clinical applications, our goal is to generate physically accurate three-dimensional (3D) abscess models upon which bacteria can be grown. Here, we report results of MB-PDT against four representative bacterial species found in human abscesses in planktonic culture, as biofilms on silicone, and pilot results in 3D silicone molds derived from human abscess computed tomography (CT) images. In all cases, MB-PDT was performed with 665 nm light at a fluence rate of 4 mW/cm[2] for 30 minutes, resulting in a fluence of 7.2 J/cm[2]. In planktonic cultures, MB-PDT was effective against Escherichia coli, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) (4- to 7-fold log CFU reduction). For Klebsiella pneumoniae, increased fluence was required to achieve comparable efficacy. When bacteria were grown as biofilms on silicone, MB-PDT efficacy was reduced (1- to 2-fold CFU reduction). A 3D silicone model was generated based on pelvic abscess CT images, and MRSA was grown in this model for six days. Crystal violet staining showed abundant growth on the silicone, without penetration into the model. These results motivate exploration of both light and drug dose ranging for biofilm samples. Future experiments will additionally focus on MB-PDT of bacteria grown on 3D silicone surfaces.}, } @article {pmid37771391, year = {2023}, author = {Vyas, HKN and Xia, B and Alam, D and Gracie, NP and Rothwell, JG and Rice, SA and Carter, D and Cullen, PJ and Mai-Prochnow, A}, title = {Plasma activated water as a pre-treatment strategy in the context of biofilm-infected chronic wounds.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100154}, pmid = {37771391}, issn = {2590-2075}, abstract = {Healing and treatment of chronic wounds are often complicated due to biofilm formation by pathogens. Here, the efficacy of plasma activated water (PAW) as a pre-treatment strategy has been investigated prior to the application of topical antiseptics polyhexamethylene biguanide, povidone iodine, and MediHoney, which are routinely used to treat chronic wounds. The efficacy of this treatment strategy was determined against biofilms of Escherichia coli formed on a plastic substratum and on a human keratinocyte monolayer substratum used as an in vitro biofilm-skin epithelial cell model. PAW pre-treatment greatly increased the killing efficacy of all the three antiseptics to eradicate the E. coli biofilms formed on the plastic and keratinocyte substrates. However, the efficacy of the combined PAW-antiseptic treatment and single treatments using PAW or antiseptic alone was lower for biofilms formed in the in vitro biofilm-skin epithelial cell model compared to the plastic substratum. Scavenging assays demonstrated that reactive species present within the PAW were largely responsible for its anti-biofilm activity. PAW treatment resulted in significant intracellular reactive oxygen and nitrogen species accumulation within the E. coli biofilms, while also rapidly acting on the microbial membrane leading to outer membrane permeabilisation and depolarisation. Together, these factors contribute to significant cell death, potentiating the antibacterial effect of the assessed antiseptics.}, } @article {pmid37768099, year = {2023}, author = {Ghesquière, J and Simoens, K and Koos, E and Boon, N and Teughels, W and Bernaerts, K}, title = {Spatiotemporal monitoring of a periodontal multispecies biofilm model: demonstration of prebiotic treatment responses.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0108123}, doi = {10.1128/aem.01081-23}, pmid = {37768099}, issn = {1098-5336}, abstract = {Biofilms are complex polymicrobial communities which are often associated with human infections such as the oral disease periodontitis. Studying these complex communities under controlled conditions requires in vitro biofilm model systems that mimic the natural environment as close as possible. This study established a multispecies periodontal model in the drip flow biofilm reactor in order to mimic the continuous flow of nutrients at the air-liquid interface in the oral cavity. The design is engineered to enable real-time characterization. A community of five bacteria, Streptococcus gordonii-GFPmut3*, Streptococcus oralis-GFPmut3*, Streptococcus sanguinis-pVMCherry, Fusobacterium nucleatum, and Porphyromonas gingivalis-SNAP26 is visualized using two distinct fluorescent proteins and the SNAP-tag. The biofilm in the reactor develops into a heterogeneous, spatially uniform, dense, and metabolically active biofilm with relative cell abundances similar to those in a healthy individual. Metabolic activity, structural features, and bacterial composition of the biofilm remain stable from 3 to 6 days. As a proof of concept for our periodontal model, the 3 days developed biofilm is exposed to a prebiotic treatment with L-arginine. Multifaceted effects of L-arginine on the oral biofilm were validated by this model setup. L-arginine showed to inhibit growth and incorporation of the pathogenic species and to reduce biofilm thickness and volume. Additionally, L-arginine is metabolized by Streptococcus gordonii-GFPmut3* and Streptococcus sanguinis-pVMCherry, producing high levels of ornithine and ammonium in the biofilm. In conclusion, our drip flow reactor setup is promising in studying spatiotemporal behavior of a multispecies periodontal community. IMPORTANCE Periodontitis is a multifactorial chronic inflammatory disease in the oral cavity associated with the accumulation of microorganisms in a biofilm. Not the presence of the biofilm as such, but changes in the microbiota (i.e., dysbiosis) drive the development of periodontitis, resulting in the destruction of tooth-supporting tissues. In this respect, novel treatment approaches focus on maintaining the health-associated homeostasis of the resident oral microbiota. To get insight in dynamic biofilm responses, our research presents the establishment of a periodontal biofilm model including Streptococcus gordonii, Streptococcus oralis, Streptococcus sanguinis, Fusobacterium nucleatum, and Porphyromonas gingivalis. The added value of the model setup is the combination of simulating continuously changing natural mouth conditions with spatiotemporal biofilm profiling using non-destructive characterization tools. These applications are limited for periodontal biofilm research and would contribute in understanding treatment mechanisms, short- or long-term exposure effects, the adaptation potential of the biofilm and thus treatment strategies.}, } @article {pmid37768087, year = {2023}, author = {Wang, M and Lu, J and Qin, P and Wang, S and Ding, W and Fu, HH and Zhang, YZ and Zhang, W}, title = {Biofilm formation stabilizes metabolism in a Roseobacteraceae bacterium under temperature increase.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0060123}, doi = {10.1128/aem.00601-23}, pmid = {37768087}, issn = {1098-5336}, abstract = {Ocean warming profoundly impacts microbes in marine environments; yet, how lifestyle (e.g., free living versus biofilm associated) affects the bacterial response to rising temperature is not clear. Here, we compared transcriptional, enzymatic, and physiological responses of free-living and biofilm-associated Leisingera aquaemixtae M597, a member of the Roseobacteraceae family isolated from marine biofilms, to the increase in temperature from 25℃ to 31℃. Complete genome sequencing and metagenomics revealed the prevalence of M597 in global ocean biofilms. Transcriptomics suggested a significant effect on the expression of genes related to carbohydrate metabolism, nitrogen and sulfur metabolism, and phosphorus utilization of free-living M597 cells due to temperature increase, but such drastic alterations were not observed in its biofilms. In the free-living state, the transcription of the key enzyme participating in the Embden-Meyerhof-Parnas pathway was significantly increased due to the increase in temperature, accompanied by a substantial decrease in the Entner-Doudoroff pathway, but transcripts of these glycolytic enzymes in biofilm-forming strains were independent of the temperature variation. The correlation between the growth condition and the shift in glycolytic pathways under temperature change was confirmed by enzymatic activity assays. Furthermore, the rising temperature affected the growth rate and the production of intracellular reactive oxygen species when M597 cells were free living rather than in biofilms. Thus, biofilm formation stabilizes metabolism in M597 when grown under high temperature and this homeostasis is probably related to the glycolytic pathways.IMPORTANCEBiofilm formation is one of the most successful strategies employed by microbes against environmental fluctuations. In this study, using a marine Roseobacteraceae bacterium, we studied how biofilm formation affects the response of marine bacteria to the increase in temperature. This study enhances our understanding of the function of bacterial biofilms and the microbe-environment interactions in the framework of global climate change.}, } @article {pmid37768046, year = {2023}, author = {Brahma, P and Aggarwal, R and Sanyal, K}, title = {Biased eviction of variant histone H3 nucleosomes triggers biofilm growth in Candida albicans.}, journal = {mBio}, volume = {}, number = {}, pages = {e0206323}, doi = {10.1128/mbio.02063-23}, pmid = {37768046}, issn = {2150-7511}, abstract = {Candida albicans is an opportunistic human pathogen that colonizes the gastrointestinal and genitourinary tracts of healthy individuals. C. albicans yeast cells can switch to filamentous forms. On biotic and abiotic surfaces, the planktonic free-floating yeast cells often form biofilms, a multi-drug-resistant three-dimensional community of yeast and filamentous cells. While alterations in gene expression patterns during planktonic to biofilm growth transitions in C. albicans have been studied, the underlying molecular mechanisms largely remain unexplored. Previously, we identified a histone H3 variant (H3V[CTG]), which acts as a negative regulator of biofilm growth in C. albicans. In the current study, we performed genome-wide profiling of H3V[CTG] nucleosomes in C. albicans planktonic cells and found them to be enriched at promoter regions. In planktonic cells, H3V[CTG]-enriched regions are mostly devoid of histone H3 post-translational modifications that allow active transcription, thus strengthening the role of H3V[CTG] as a negative regulator of biofilm formation. By combining genome-wide transcriptional alterations, nucleosome positioning (MNase-seq), and DNA accessibility (ATAC-seq) assays, we show a significant reduction in the total number of nucleosomes in biofilm cells as compared to planktonic cells indicating a more open chromatin state during biofilm growth. Finally, we propose that H3V[CTG]-nucleosome eviction at promoters of biofilm-relevant genes in biofilm-grown cells contributes to achieve the open chromatin state by facilitating easy promoter access of master regulators (activators and repressors) for modulation of gene expression observed during growth phase transitions. IMPORTANCE Candida albicans lives as a commensal in most healthy humans but can cause superficial skin infections to life-threatening systemic infections. C. albicans also forms biofilms on biotic and abiotic surfaces. Biofilm cells are difficult to treat and highly resistant to antifungals. A specific set of genes is differentially regulated in biofilm cells as compared to free-floating planktonic cells of C. albicans. In this study, we addressed how a variant histone H3V[CTG], a previously identified negative regulator of biofilm formation, modulates gene expression changes. By providing compelling evidence, we show that biased eviction of H3V[CTG] nucleosomes at the promoters of biofilm-relevant genes facilitates the accessibility of both transcription activators and repressors to modulate gene expression. Our study is a comprehensive investigation of genome-wide nucleosome occupancy in both planktonic and biofilm states, which reveals transition to an open chromatin landscape during biofilm mode of growth in C. albicans, a medically relevant pathogen.}, } @article {pmid37767258, year = {2023}, author = {Kountchou, CL and Noubom, M and Ndezo Bisso, B and Ngouana Kammalac, T and Ekpo, AI and Ngueguim Dougue, A and Nangwat, C and Oyono, M and Ranque, S and Dzoyem, JP}, title = {Antifungal Resistance Profile, Biofilm Formation, and Virulence Factor Production in Candida krusei Isolates From HIV-Infected Patients in Cameroon.}, journal = {Cureus}, volume = {15}, number = {8}, pages = {e44213}, pmid = {37767258}, issn = {2168-8184}, abstract = {Background Fungal infections mainly caused by Candida krusei are increasing rapidly and represent a serious public health problem in human immunodeficiency virus (HIV)-infected patients. This study aimed to investigate the antifungal susceptibility profile and virulence factors in C. krusei isolated from HIV-infected patients. Methodology Isolates were identified by biochemical and molecular methods. The antifungal resistance profile was established based on the antifungal susceptibility test performed using the Sensititre YeastOne™ (Thermo Fisher Scientific, Waltham, MA) microdilution technique. The production of phospholipase and proteinase was detected by standard methods. Biofilm formation was performed by the microtiter plate method. Results A total of 73 isolates of C. krusei were recovered from stool, oral swabs, vaginal swabs, and urine samples. The highest number of C. krusei isolates (49, 67.05%)was recovered from stool samples. A total of 32.56% of the C. krusei isolates were multidrug-resistant (MDR). The patients living with HIV and not receiving antiretroviral treatment displayed the highest number of C. krusei isolates (29, 39.76%), whereas the patients living with HIV on antiretroviral therapy exhibited the lowest number of C. krusei isolates (2, 2.72%). All isolates were categorized as strong biofilm producers. Among the production of hydrolytic enzymes, 25 (58.13%) and 24 (55.81%) of C. krusei isolates were classified as strong phospholipase and proteinase producers, respectively. Conclusion The C. krusei isolates obtained in this study were MDR and strongly expressed biofilm formation and both phospholipase and proteinase hydrolytic enzymes. The results show how pathogenic C. krusei is in the HIV-infected population and will contribute toward the management of C. krusei-related infections, which may help improve the life quality of people living with HIV.}, } @article {pmid37764949, year = {2023}, author = {Parente, R and Fumagalli, MR and Di Claudio, A and Cárdenas Rincón, CL and Erreni, M and Zanini, D and Iapichino, G and Protti, A and Garlanda, C and Rusconi, R and Doni, A}, title = {A Multilayered Imaging and Microfluidics Approach for Evaluating the Effect of Fibrinolysis in Staphylococcus aureus Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/pathogens12091141}, pmid = {37764949}, issn = {2076-0817}, support = {PE00000007//NextgenerationEU-MUR PNRR Extended Partnership initiative on Emerging Infectious Diseases/ ; 21147//Italian Association for Cancer Research/ ; 23465//Italian Association for Cancer Research/ ; }, abstract = {The recognition of microbe and extracellular matrix (ECM) is a recurring theme in the humoral innate immune system. Fluid-phase molecules of innate immunity share regulatory roles in ECM. On the other hand, ECM elements have immunological functions. Innate immunity is evolutionary and functionally connected to hemostasis. Staphylococcus aureus (S. aureus) is a major cause of hospital-associated bloodstream infections and the most common cause of several life-threatening conditions such as endocarditis and sepsis through its ability to manipulate hemostasis. Biofilm-related infection and sepsis represent a medical need due to the lack of treatments and the high resistance to antibiotics. We designed a method combining imaging and microfluidics to dissect the role of elements of the ECM and hemostasis in triggering S. aureus biofilm by highlighting an essential role of fibrinogen (FG) in adhesion and formation. Furthermore, we ascertained an important role of the fluid-phase activation of fibrinolysis in inhibiting biofilm of S. aureus and facilitating an antibody-mediated response aimed at pathogen killing. The results define FG as an essential element of hemostasis in the S. aureus biofilm formation and a role of fibrinolysis in its inhibition, while promoting an antibody-mediated response. Understanding host molecular mechanisms influencing biofilm formation and degradation is instrumental for the development of new combined therapeutic approaches to prevent the risk of S. aureus biofilm-associated diseases.}, } @article {pmid37764946, year = {2023}, author = {Mahrous, SH and El-Balkemy, FA and Abo-Zeid, NZ and El-Mekkawy, MF and El Damaty, HM and Elsohaby, I}, title = {Antibacterial and Anti-Biofilm Activities of Cinnamon Oil against Multidrug-Resistant Klebsiella pneumoniae Isolated from Pneumonic Sheep and Goats.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/pathogens12091138}, pmid = {37764946}, issn = {2076-0817}, abstract = {The primary objectives were to isolate and identify Klebsiella pneumoniae (K. pneumoniae), and determine the antimicrobial resistance patterns and biofilm formation abilities of the isolates. Additionally, the study aimed to investigate the antimicrobial and anti-biofilm effects of cinnamon oil against K. pneumoniae isolates. A cross-sectional study was conducted from March 2022 to April 2023 to collect 200 samples (including 156 nasal swabs and 44 lung specimens) from pneumonic sheep and goats admitted to the Veterinary Teaching Hospital of Zagazig University, Egypt. K. pneumoniae was isolated from a total of 72 (36%) samples, with 53 (73.6%) isolates recovered from nasal swabs and 19 (26.4%) from lung samples. Among the samples, 52 (36.9%) were from sheep and 20 (33.9%) were from goats. Antimicrobial susceptibility testing of the 72 K. pneumoniae isolates to 18 antimicrobials revealed that all isolates were resistant to ampicillin, amoxicillin/clavulanic acid, cefotaxime, ceftriaxone, tetracycline, colistin, fosfomycin, and trimethoprim/sulphamethoxazole. None of the isolates were resistant to amikacin, imipenem, and norfloxacin. Multidrug resistance (MDR) was observed in all K. pneumoniae isolates recovered from sheep and goats. The average MAR index was 0.71, ranging from 0.50 to 0.83. Regarding biofilm formation, among the K. pneumoniae isolates with a high MAR index (n = 30), 10% exhibited strong formation, 40% showed moderate formation, 43.3% displayed weak formation, and 6.7% did not form biofilms. Additionally, the biofilm-forming genes treC and fimA were present in all 28 biofilm-forming K. pneumoniae isolates, while the mrkA gene was detected in 15 (53.6%) of the 28 isolates. MDR K. pneumoniae isolates with strong biofilm formation abilities were treated with cinnamon oil at varying concentrations (100%, 75%, 50%, and 25%). This treatment resulted in inhibition zone diameters ranging from 35 to 45 mm. Cinnamon oil exhibited lower minimum inhibitory concentration and minimum bactericidal concentration values compared to norfloxacin for all isolates. Additionally, cinnamon oil significantly reduced the expression of biofilm-associated genes (treC, fimA, and mrkA) when compared to isolates treated with norfloxacin or untreated. In conclusion, this study identified a high level of MDR K. pneumoniae with strong and moderate biofilm formation abilities in pneumonic sheep and goats in Sharika Governorate, Egypt. Although cinnamon oil demonstrated potential antibacterial and anti-biofilm properties against K. pneumoniae, further research is required to investigate its effectiveness in treating K. pneumoniae infections in pneumonic sheep and goats.}, } @article {pmid37764909, year = {2023}, author = {Ullah, MA and Islam, MS and Rana, ML and Ferdous, FB and Neloy, FH and Firdous, Z and Hassan, J and Rahman, MT}, title = {Resistance Profiles and Virulence Determinants in Biofilm-Forming Enterococcus faecium Isolated from Raw Seafood in Bangladesh.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/pathogens12091101}, pmid = {37764909}, issn = {2076-0817}, support = {2022/12/BAU//Bangladesh Agricultural University Research System (BAURES)/ ; }, abstract = {Pathogenic, antibiotic-resistant, and biofilm-forming bacteria can be transferred to humans through the consumption of contaminated seafood. The present study was carried out to determine antibiotic resistance profiles and virulence determinants in biofilm-forming Enterococcus faecium isolated from seafood in Bangladesh. A total of 150 seafood samples, including shrimp (n = 50), crabs (n = 25), and marine fish (n = 75), were screened using cultural, staining, biochemical, polymerase chain reaction (PCR), Congo red (CR), and disk diffusion (DD) assays. In PCR, E. faecium was detected in 27.3% (41/150; CI95% 20.8; 34.9) of samples, where marine fish (34.7%, CI95% 24.9; 45.9) had the highest prevalence (p < 0.05) compared to crabs (32%, CI95% 17.2; 51.6) and shrimp (14%, CI95% 7.0; 26.1). Thirty-two (78.1%, CI95% 63.3; 88.0) of the E. faecium isolates were determined to be biofilm formers in the CR test, where 43.9% (18/41, CI95% 29.9; 59.0) and 34.2% (14/41, CI95% 21.6; 49.5) of the isolates were strong and intermediate biofilm formers, respectively. In PCR, virulence genes, i.e., pil (100%), ace (92.7%), agg (68.3%), fsrA (65.9%), gelE (63.4%), sprE (53.7%), fsrB (51.2%), and fsrC (43.9%), were detected in E. faecium isolates. All the E. faecium isolates were phenotypically resistant to ≥3 antimicrobial categories and ≥3 antibiotics, including WHO-classified reserve antibiotics linezolid (70.7%) and fosfomycin (19.5%). Moreover, the multiple antibiotic resistance index ranged up to 0.8, showing resistance to ten antibiotics and eight antibiotic classes. In this study, the prevalence of virulence genes and antibiotic resistance was significantly greater (p < 0.05) in strong biofilm-forming E. faecium strains as compared to strains with intermediate and non-biofilm-forming abilities. As far as we know, this study, for the first time in Bangladesh, determined antibiotic resistance and detected virulence genes in biofilm-forming E. faecium isolated from seafood samples. The data from this study could play a significant role in evaluating potential health hazards linked to the ingestion of uncooked or minimally processed seafood.}, } @article {pmid37764160, year = {2023}, author = {Moreno-Manjón, J and Castillo-Ramírez, S and Jolley, KA and Maiden, MCJ and Gayosso-Vázquez, C and Fernández-Vázquez, JL and Mateo-Estrada, V and Giono-Cerezo, S and Alcántar-Curiel, MD}, title = {Acinetobacter baumannii IC2 and IC5 Isolates with Co-Existing blaOXA-143-like and blaOXA-72 and Exhibiting Strong Biofilm Formation in a Mexican Hospital.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092316}, pmid = {37764160}, issn = {2076-2607}, support = {171880//Consejo Nacional de Ciencia y Tecnología (CONACyT México) Ciencia de Frontera/ ; IN217721//Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT-DGAPA-UNAM)/ ; 284276//Consejo Nacional de Ciencia y Tecnología (CONACYT)/ ; 20220248//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional (SIP, IPN)/ ; }, abstract = {Acinetobacter baumannii is an opportunistic pathogen responsible for healthcare-associated infections (HAIs) and outbreaks. Antimicrobial resistance mechanisms and virulence factors allow it to survive and spread in the hospital environment. However, the molecular mechanisms of these traits and their association with international clones are frequently unknown in low- and middle-income countries. Here, we analyze the phenotype and genotype of seventy-six HAIs and outbreak-causing A. baumannii isolates from a Mexican hospital over ten years, with special attention to the carbapenem resistome and biofilm formation. The isolates belonged to the global international clone (IC) 2 and the Latin America endemic IC5 and were predominantly extensively drug-resistant (XDR). Oxacillinases were identified as a common source of carbapenem resistance. We noted the presence of the blaOXA-143-like family (not previously described in Mexico), the blaOXA-72 and the blaOXA-398 found in both ICs. A low prevalence of efflux pump overexpression activity associated with carbapenem resistance was observed. Finally, strong biofilm formation was found, and significant biofilm-related genes were identified, including bfmRS, csuA/BABCDE, pgaABCD and ompA. This study provides a comprehensive profile of the carbapenem resistome of A. baumannii isolates belonging to the same pulse type, along with their significant biofilm formation capacity. Furthermore, it contributes to a better understanding of their role in the recurrence of infection and the endemicity of these isolates in a Mexican hospital.}, } @article {pmid37764142, year = {2023}, author = {Moore, K and Li, A and Gupta, N and Gupta, TT and Delury, C and Aiken, SS and Laycock, PA and Stoodley, P}, title = {Killing of a Multispecies Biofilm Using Gram-Negative and Gram-Positive Targeted Antibiotic Released from High Purity Calcium Sulfate Beads.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092296}, pmid = {37764142}, issn = {2076-2607}, support = {Not applicable.//Biocomposites Ltd/ ; }, abstract = {BACKGROUND: Multispecies biofilm orthopedic infections are more challenging to treat than mono-species infections. In this in-vitro study, we aimed to determine if a multispecies biofilm, consisting of Gram positive and negative species with different antibiotic susceptibilities could be treated more effectively using high purity antibiotic-loaded calcium sulfate beads (HP-ALCSB) containing vancomycin (VAN) and tobramycin (TOB) in combination than alone.

METHODS: Three sets of species pairs from bioluminescent strains of Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) and clinical isolates, Enterococcus faecalis (EF) and Enterobacter cloacae were screened for compatibility. PA + EF developed intermixed biofilms with similar cell concentrations and so were grown on 316L stainless steel coupons for 72 h or as 24 h agar lawn biofilms and then treated with HP-ALCSBs with single or combination antibiotics and assessed by viable count or bioluminescence and light imaging to distinguish each species. Replica plating was used to assess viability.

RESULTS: The VAN + TOB bead significantly reduced the PA + EF biofilm CFU and reduced the concentration of surviving antibiotic tolerant variants by 50% compared to single antibiotics.

CONCLUSIONS: The combination of Gram-negative and positive targeted antibiotics released from HP-ALCSBs may be more effective in treating multispecies biofilms than monotherapy alone.}, } @article {pmid37764072, year = {2023}, author = {Aslam, M and Pei, P and Ye, P and Li, T and Liang, H and Zhang, Z and Ke, X and Chen, W and Du, H}, title = {Unraveling the Diverse Profile of N-Acyl Homoserine Lactone Signals and Their Role in the Regulation of Biofilm Formation in Porphyra haitanensis-Associated Pseudoalteromonas galatheae.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092228}, pmid = {37764072}, issn = {2076-2607}, support = {41976125//National Natural Science Foundation of China/ ; 42206116//National Natural Science Foundation of China/ ; 2022KCXTD008//Program for University Innovation Team of Guangdong Province/ ; 2018KCXTD012//Team Project of the Department of Education of Guangdong Province/ ; }, abstract = {N-acyl homoserine lactones (AHLs) are small, diffusible chemical signal molecules that serve as social interaction tools for bacteria, enabling them to synchronize their collective actions in a density-dependent manner through quorum sensing (QS). The QS activity from epiphytic bacteria of the red macroalgae Porphyra haitanensis, along with its involvement in biofilm formation and regulation, remains unexplored in prior scientific inquiries. Therefore, this study explores the AHL signal molecules produced by epiphytic bacteria. The bacterium isolated from the surface of P. haitanensis was identified as Pseudoalteromonas galatheae by 16s rRNA gene sequencing and screened for AHLs using two AHL reporter strains, Agrobacterium tumefaciens A136 and Chromobacterium violaceum CV026. The crystal violet assay was used for the biofilm-forming phenotype. The inferences revealed that P. galatheae produces four different types of AHL molecules, i.e., C4-HSL, C8-HSL, C18-HSL, and 3-oxo-C16-HSL, and it was observed that its biofilm formation phenotype is regulated by QS molecules. This is the first study providing insights into the QS activity, diverse AHL profile, and regulatory mechanisms that govern the biofilm formation phenotype of P. galatheae. These findings offer valuable insights for future investigations exploring the role of AHL producing epiphytes and biofilms in the life cycle of P. haitanensis.}, } @article {pmid37764045, year = {2023}, author = {Desjardins, A and Zerfas, P and Filion, D and Palmer, RJ and Falcone, EL}, title = {Mucispirillum schaedleri: Biofilm Architecture and Age-Dependent Pleomorphy.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092200}, pmid = {37764045}, issn = {2076-2607}, support = {xxxx//Canada Research Chairs/ ; Clinician-Scholar Junior 1 award//Fonds de Recherche du Québec-Santé (FRQ-S)/ ; xxxx//J-Louis Lévesque Foundation Research Chair/ ; ZIC DE000750-01//Intramural Research Program of the National Institute of Dental and Craniofacial Research (NIDCR) and the NIDCR Imaging Core/ ; }, abstract = {Round bodies in spirochete cultures have been a controversial subject since their description seven decades ago. We report the existence of round bodies (spherical cells) in cultures of Mucispirillum schaedleri, a spiral bacterium phylogenetically distant from spirochetes. Furthermore, when grown in biofilms, M. schaedleri demonstrates a unique morphology known as cording, which has been previously described only in mycobacteria. Thus, M. schaedleri has two distinct features, each previously thought to be unique to two different phylogenetically distant groups of bacteria.}, } @article {pmid37764040, year = {2023}, author = {Natali, V and Malfatti, F and Cibic, T}, title = {Ecological Effect of Differently Treated Wooden Materials on Microalgal Biofilm Formation in the Grado Lagoon (Northern Adriatic Sea).}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092196}, pmid = {37764040}, issn = {2076-2607}, abstract = {Within the framework of the Interreg Italy-Slovenia programme, the project DuraSoft aimed at testing innovative technologies to improve the durability of traditional wooden structures in socio-ecologically sensitive environments. We focused on the impact of different wood treatments (i.e., copper-based coatings and thermal modification) on microbial biofilm formation in the Grado Lagoon. Wooden samples were placed in 2 areas with diverse hydrodynamic conditions and retrieved after 6, 20, and 40 days. Light, confocal and scanning electron microscopy were employed to assess the treatment effects on the microalgal community abundance and composition. Lower hydrodynamics accelerated the colonisation, leading to higher algal biofilm abundances, regardless of the treatment. The Cu-based agents induced modifications to the microalgal community, leading to lower densities, small-sized diatoms and frequent deformities (e.g., bent apices, frustule malformation) in the genera Cylindrotheca and Cocconeis. After 20 days, taxa forming 3D mucilaginous structures, such as Licmophora and Synedra, were present on chemically treated panels compared to natural ones. While in the short term, the treatments were effective as antifouling agents, in the long term, neither the copper-based coatings nor the thermal modification successfully slowed down the biofouling colonisation, likely due to the stimulating effect of nutrients and other substances released from these solutions. The need to develop more ecosystem friendly technologies to preserve wooden structures remains urgent.}, } @article {pmid37764030, year = {2023}, author = {Qin, H and Liu, Y and Zhai, Z and Xiao, B}, title = {Biofilm-Forming Capacity and Drug Resistance of Different Gardnerella Subgroups Associated with Bacterial Vaginosis.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092186}, pmid = {37764030}, issn = {2076-2607}, abstract = {Bacterial vaginosis (BV) is the most common infection of the lower reproductive tract among women of reproductive age. Recurrent infections and antibiotic resistance associated with biofilms remain significant challenges for BV treatment. Gardnerella species are commonly found in women with and without BV, indicating that genetic differences among Gardnerella isolates may distinguish pathogenic from commensal subgroups. This study isolated 11 Gardnerella strains from vaginal samples obtained from women with BV before or after treatment. The biofilm formation ability of each strain was examined by crystal violet staining. Eight strains were selected using phylogenetic analysis of the cpn60 sequences and classified as subgroups A (6/8), B (1/8), and D (1/8). The biofilm formation ability and antibiotic resistance profile of these strains was compared among the subgroups. Subgroup D had the strongest biofilm formation ability. Six of the planktonic strains exhibited resistance to the first-line BV drug, metronidazole, and one to clindamycin. Moreover, biofilm formation in vitro increased strain resistance to clindamycin. Two strains with strong biofilm ability, S20 and S23, and two with weak biofilm ability, S24 and S25, were selected for comparative genomic analysis. S20 and S23 were found to contain four key genes associated with biofilm formation and more genes involved in carbohydrate synthesis and metabolism than S24 and S25. Identifying differences in the expression of virulence factors between Gardnerella subgroups could inform the development of novel treatments for BV.}, } @article {pmid37764028, year = {2023}, author = {Ladewig, L and Gloy, L and Langfeldt, D and Pinnow, N and Weiland-Bräuer, N and Schmitz, RA}, title = {Antimicrobial Peptides Originating from Expression Libraries of Aurelia aurita and Mnemiopsis leidyi Prevent Biofilm Formation of Opportunistic Pathogens.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092184}, pmid = {37764028}, issn = {2076-2607}, support = {CRC1182 "Origin and Function of Metaorganisms"//Deutsche Forschungsgemeinschaft/ ; MarBiotech 031B0562B//Federal Ministry of Education and Research/ ; }, abstract = {The demand for novel antimicrobial compounds is rapidly growing due to the rising appearance of antibiotic resistance in bacteria; accordingly, alternative approaches are urgently needed. Antimicrobial peptides (AMPs) are promising, since they are a naturally occurring part of the innate immune system and display remarkable broad-spectrum activity and high selectivity against various microbes. Marine invertebrates are a primary resource of natural AMPs. Consequently, cDNA expression (EST) libraries from the Cnidarian moon jellyfish Aurelia aurita and the Ctenophore comb jelly Mnemiopsis leidyi were constructed in Escherichia coli. Cell-free size-fractionated cell extracts (<3 kDa) of the two libraries (each with 29,952 clones) were consecutively screened for peptides preventing the biofilm formation of opportunistic pathogens using the crystal violet assay. The 3 kDa fraction of ten individual clones demonstrated promising biofilm-preventing activities against Klebsiella oxytoca and Staphylococcus epidermidis. Sequencing the respective activity-conferring inserts allowed for the identification of small ORFs encoding peptides (10-22 aa), which were subsequently chemically synthesized to validate their inhibitory potential. Although the peptides are likely artificial products from a random translation of EST inserts, the biofilm-preventing effects against K. oxytoca, Pseudomonas aeruginosa, S. epidermidis, and S. aureus were verified for five synthetic peptides in a concentration-dependent manner, with peptide BiP_Aa_5 showing the strongest effects. The impact of BiP_Aa_2, BiP_Aa_5, and BiP_Aa_6 on the dynamic biofilm formation of K. oxytoca was further validated in microfluidic flow cells, demonstrating a significant reduction in biofilm thickness and volume by BiP_Aa_2 and BiP_Aa_5. Overall, the structural characteristics of the marine invertebrate-derived AMPs, their physicochemical properties, and their promising antibiofilm effects highlight them as attractive candidates for discovering new antimicrobials.}, } @article {pmid37764010, year = {2023}, author = {Mao, P and Wang, Y and Li, L and Ji, S and Li, P and Liu, L and Chen, J and Sun, H and Luo, X and Ye, C}, title = {The Isolation, Genetic Analysis and Biofilm Characteristics of Listeria spp. from the Marine Environment in China.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092166}, pmid = {37764010}, issn = {2076-2607}, support = {2021ZZKT003//National Institute for Communicable Disease Control and Prevention/ ; 102393220020020000029//National Institute for Communicable Disease Control and Prevention/ ; }, abstract = {Listeria monocytogenes is an important pathogen that can cause listeriosis. Despite the growing recognition of Listeria spp. as a foodborne and environmental pathogen, the understanding of its prevalence and characteristics of Listeria spp. in the marine environment remains unknown. In this study, we first investigated the genetic and phenotypic characteristics of Listeria species isolated in a coastal city in China. The findings revealed that the sequence type 87 (ST87) L. monocytogenes, a prevalent clinical and seafood strain in China, dominates in recreational beach sands and possesses a notable biofilm-forming capacity in seawater. The presence of ST87 L. monocytogenes in coastal environments indicates the potential health risks for both recreational activities and seafood consumption. Moreover, the ST121 isolates from sand had a versatile plasmid encoding multifunctional genes, including uvrX for UV resistance, gbuC for salt resistance, and npx for oxidative resistance and multiple transposases, which potentially aid in survival under natural environments. Black-headed gulls potentially facilitate the spread of L. monocytogenes, with similar ST35 strains found in gulls and beach sand. As a reservoir of microbes from marine environments and human/animal excrement, coastal sand would play an important role in the spread of L. monocytogenes and is an environmental risk for human listeriosis.}, } @article {pmid37764007, year = {2023}, author = {Liaqat, I and Khalid, A and Rubab, S and Rashid, F and Latif, AA and Naseem, S and Bibi, A and Khan, BN and Ansar, W and Javed, A and Afzaal, M and Summer, M and Majid, S and Ali, S and Aftab, MN}, title = {In Vitro Biofilm-Mediated Biodegradation of Pesticides and Dye-Contaminated Effluents Using Bacterial Biofilms.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092163}, pmid = {37764007}, issn = {2076-2607}, support = {75/ORIC/23.//The current work was funded by the Office of Research Innovation & Commercialization (ORIC), Government College University, Lahore, Pakistan, via Project No. 75/ORIC/23./ ; }, abstract = {Overuse of pesticides in agricultural soil and dye-polluted effluents severely contaminates the environment and is toxic to animals and humans making their removal from the environment essential. The present study aimed to assess the biodegradation of pesticides (cypermethrin (CYP) and imidacloprid (IMI)), and dyes (malachite green (MG) and Congo red (CR)) using biofilms of bacteria isolated from pesticide-contaminated soil and dye effluents. Biofilms of indigenous bacteria, i.e., Bacillus thuringiensis 2A (OP554568), Enterobacter hormaechei 4A (OP723332), Bacillus sp. 5A (OP586601), and Bacillus cereus 6B (OP586602) individually and in mixed culture were tested against CYP and IMI. Biofilms of indigenous bacteria i.e., Lysinibacillus sphaericus AF1 (OP589134), Bacillus sp. CF3 (OP589135) and Bacillus sp. DF4 (OP589136) individually and in mixed culture were tested for their ability to degrade dyes. The biofilm of a mixed culture of B. thuringiensis + Bacillus sp. (P7) showed 46.2% degradation of CYP compared to the biofilm of a mixed culture of B. thuringiensis + E. hormaechei + Bacillus sp. + B. cereus (P11), which showed significantly high degradation (70.0%) of IMI. Regarding dye biodegradation, a mixed culture biofilm of Bacillus sp. + Bacillus sp. (D6) showed 86.76% degradation of MG, which was significantly high compared to a mixed culture biofilm of L. sphaericus + Bacillus sp. (D4) that degraded only 30.78% of CR. UV-VIS spectroscopy revealed major peaks at 224 nm, 263 nm, 581 nm and 436 nm for CYP, IMI, MG and CR, respectively, which completely disappeared after treatment with bacterial biofilms. Fourier transform infrared (FTIR) analysis showed the appearance of new peaks in degraded metabolites and disappearance of a peak in the control spectrum after biofilm treatment. Thin layer chromatography (TLC) analysis also confirmed the degradation of CYP, IMI, MG and CR into several metabolites compared to the control. The present study demonstrates the biodegradation potential of biofilm-forming bacteria isolated from pesticide-polluted soil and dye effluents against pesticides and dyes. This is the first report demonstrating biofilm-mediated bio-degradation of CYP, IMI, MG and CR utilizing soil and effluent bacterial flora from Multan and Sheikhupura, Punjab, Pakistan.}, } @article {pmid37764005, year = {2023}, author = {Dicks, LMT}, title = {Biofilm Formation of Clostridioides difficile, Toxin Production and Alternatives to Conventional Antibiotics in the Treatment of CDI.}, journal = {Microorganisms}, volume = {11}, number = {9}, pages = {}, doi = {10.3390/microorganisms11092161}, pmid = {37764005}, issn = {2076-2607}, abstract = {Clostridioides difficile is considered a nosocomial pathogen that flares up in patients exposed to antibiotic treatment. However, four out of ten patients diagnosed with C. difficile infection (CDI) acquired the infection from non-hospitalized individuals, many of whom have not been treated with antibiotics. Treatment of recurrent CDI (rCDI) with antibiotics, especially vancomycin (VAN) and metronidazole (MNZ), increases the risk of experiencing a relapse by as much as 70%. Fidaxomicin, on the other hand, proved more effective than VAN and MNZ by preventing the initial transcription of RNA toxin genes. Alternative forms of treatment include quorum quenching (QQ) that blocks toxin synthesis, binding of small anion molecules such as tolevamer to toxins, monoclonal antibodies, such as bezlotoxumab and actoxumab, bacteriophage therapy, probiotics, and fecal microbial transplants (FMTs). This review summarizes factors that affect the colonization of C. difficile and the pathogenicity of toxins TcdA and TcdB. The different approaches experimented with in the destruction of C. difficile and treatment of CDI are evaluated.}, } @article {pmid37763274, year = {2023}, author = {Zaghloul, SA and Hashem, SN and El-Sayed, SR and Badawy, MSEM and Bukhari, SI and Selim, HMRM and Riad, OKM}, title = {Evaluation of the Cariogenic and Anti-Cariogenic Potential of Human Colostrum and Colostrum-Derived Probiotics: Impact on S. mutans Growth, Biofilm Formation, and L. rhamnosus Growth.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {9}, pages = {}, doi = {10.3390/life13091869}, pmid = {37763274}, issn = {2075-1729}, abstract = {Human colostrum (HC) is essential for oral health as it is rich in probiotics that could affect the growth of the cariogenic S. mutans and its biofilm formation; hindering dental caries in advance. In this study, HC was collected from 36 healthy mothers 1-3 days postpartum. The effect of HC on oral health was carried out by assessing the impact of HC and its derived probiotics' cell-free supernatants (CFS) on the growth of S. mutans (using modified well diffusion) and its biofilm formation (using microtiter plate assay). Moreover, the effect of whole HC on L. rhamnosus, a probiotic oral bacterium, was examined. Probiotics were isolated and identified phenotypically by API 50 CH carbohydrate fermentation and genotypically by 16S rRNA amplification. The in vitro study revealed that HC has cariogenic activity and is associated with biofilm formation. Biofilm strength was inversely proportional to HC dilution (p-value < 0.0001). Nevertheless, HC and colostrum-derived probiotics improve oral health by inhibiting the growth of caries-inducing S. mutans with lower inhibition to L. rhamnosus probiotics. The CFS of isolated probiotics reduced the biofilm formation via the cariogenic S. mutans. These results are not only promising for caries eradication, but they also highlight the importance of breastfeeding infants from their first hours to shape healthy oral microbiota, protecting them from various diseases including dental caries.}, } @article {pmid37762377, year = {2023}, author = {Gentili, V and Strazzabosco, G and Salgari, N and Mancini, A and Rizzo, S and Beltrami, S and Schiuma, G and Casciano, F and Alogna, A and Passarella, D and Davinelli, S and Scapagnini, G and Medoro, A and Rizzo, R}, title = {Ozonated Oil in Liposome Eyedrops Reduces the Formation of Biofilm, Selection of Antibiotic-Resistant Bacteria, and Adhesion of Bacteria to Human Corneal Cells.}, journal = {International journal of molecular sciences}, volume = {24}, number = {18}, pages = {}, doi = {10.3390/ijms241814078}, pmid = {37762377}, issn = {1422-0067}, support = {FAR 2021//University of Ferrara/ ; }, abstract = {The recent attention to the risk of potential permanent eye damage triggered by ocular infections has been leading to a deeper investigation of the current antimicrobials. An antimicrobial agent used in ophthalmology should possess the following characteristics: a broad antimicrobial spectrum, prompt action even in the presence of organic matter, and nontoxicity. The objective of this study is to compare the antimicrobial efficacy of widely used ophthalmic antiseptics containing povidone-iodine, chlorhexidine, and liposomes containing ozonated sunflower oil. We determined the minimum inhibitory concentration (MIC) on various microbial strains: Staphylococcus aureus (ATCC 6538), methicillin-resistant Staphylococcus aureus (ATCC 33591), Staphylococcus epidermidis (ATCC 12228), Pseudomonas aeruginosa (ATCC 9027), and Escherichia coli (ATCC 873). Furthermore, we assessed its efficacy in controlling antibiotic resistance, biofilm formation, and bacterial adhesion. All three antiseptic ophthalmic preparations showed significant anti-microbicidal and anti-biofilm activity, with the liposomes containing ozonated sunflower oil with the highest ability to control antibiotic resistance and bacteria adhesion to human corneal cells.}, } @article {pmid37762317, year = {2023}, author = {Tambone, E and Ceresa, C and Marchetti, A and Chiera, S and Anesi, A and Nollo, G and Caola, I and Bosetti, M and Fracchia, L and Ghensi, P and Tessarolo, F}, title = {Rhamnolipid 89 Biosurfactant Is Effective against Streptococcus oralis Biofilm and Preserves Osteoblast Behavior: Perspectives in Dental Implantology.}, journal = {International journal of molecular sciences}, volume = {24}, number = {18}, pages = {}, doi = {10.3390/ijms241814014}, pmid = {37762317}, issn = {1422-0067}, support = {Grant for young researchers involved in excellence research projects, ref. n 2017.0340//Fondazione Cassa di Risparmio di Trento e Rovereto/ ; Call Periodontology/Implant Dentistry 2016//SIdP (Italian Society of Periodontology and Implantology), Firenze, Italy/ ; Bando Fondazione CRT, Id. 393//Università degli Studi del Piemonte Orientale/ ; Programma Operativo Nazionale (PON), Azione IV.4 - Research and Innovation, DM 1062/2021//European Union-Fondo Sociale Europeo Recovery Assistance for Cohesion and the Territories of the European Union (FSE-REACT-EU)/ ; }, abstract = {Biofilm-related peri-implant diseases represent the major complication for osteointegrated dental implants, requiring complex treatments or implant removal. Microbial biosurfactants emerged as new antibiofilm coating agents for implantable devices thanks to their high biocompatibility. This study aimed to assess the efficacy of the rhamnolipid 89 biosurfactant (R89BS) in limiting Streptococcus oralis biofilm formation and dislodging sessile cells from medical grade titanium, but preserving adhesion and proliferation of human osteoblasts. The inhibitory activity of a R89BS coating on S. oralis biofilm formation was assayed by quantifying biofilm biomass and microbial cells on titanium discs incubated up to 72 h. R89BS dispersal activity was addressed by measuring residual biomass of pre-formed biofilms after rhamnolipid treatment up to 24 h. Adhesion and proliferation of human primary osteoblasts on R89BS-coated titanium were evaluated by cell count and adenosine-triphosphate quantification, while cell differentiation was studied by measuring alkaline phosphatase activity and observing mineral deposition. Results showed that R89BS coating inhibited S. oralis biofilm formation by 80% at 72 h and dislodged 63-86% of pre-formed biofilms in 24 h according to concentration. No change in the adhesion of human osteoblasts was observed, whereas proliferation was reduced accompanied by an increase in cell differentiation. R89BS effectively counteracts S. oralis biofilm formation on titanium and preserves overall osteoblasts behavior representing a promising preventive strategy against biofilm-related peri-implant diseases.}, } @article {pmid37761984, year = {2023}, author = {Yan, CH and Chen, FH and Yang, YL and Zhan, YF and Herman, RA and Gong, LC and Sheng, S and Wang, J}, title = {The Transcription Factor CsgD Contributes to Engineered Escherichia coli Resistance by Regulating Biofilm Formation and Stress Responses.}, journal = {International journal of molecular sciences}, volume = {24}, number = {18}, pages = {}, doi = {10.3390/ijms241813681}, pmid = {37761984}, issn = {1422-0067}, support = {22278196//National Natural Science Foundation of China/ ; KYCX22_3854//Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; }, abstract = {The high cell density, immobilization and stability of biofilms are ideal characteristics for bacteria in resisting antibiotic therapy. CsgD is a transcription activating factor that regulates the synthesis of curly fimbriae and cellulose in Escherichia coli, thereby enhancing bacterial adhesion and promoting biofilm formation. To investigate the role of CsgD in biofilm formation and stress resistance in bacteria, the csgD deletion mutant ΔcsgD was successfully constructed from the engineered strain E. coli BL21(DE3) using the CRISPR/Cas9 gene-editing system. The results demonstrated that the biofilm of ΔcsgD decreased by 70.07% (p < 0.05). Additionally, the mobility and adhesion of ΔcsgD were inhibited due to the decrease in curly fimbriae and extracellular polymeric substances. Furthermore, ΔcsgD exhibited a significantly decreased resistance to acid, alkali and osmotic stress conditions (p < 0.05). RNA-Seq results revealed 491 differentially expressed genes between the parent strain and ΔcsgD, with enrichment primarily observed in metabolism-related processes as well as cell membrane structure and catalytic activity categories. Moreover, CsgD influenced the expression of biofilm and stress response genes pgaA, motB, fimA, fimC, iraP, ompA, osmC, sufE and elaB, indicating that the CsgD participated in the resistance of E. coli by regulating the expression of biofilm and stress response. In brief, the transcription factor CsgD plays a key role in the stress resistance of E. coli, and is a potential target for treating and controlling biofilm.}, } @article {pmid37760741, year = {2023}, author = {Sánchez-Somolinos, M and Díaz-Navarro, M and Benjumea, A and Matas, J and Vaquero, J and Muñoz, P and Sanz-Ruíz, P and Guembe, M}, title = {In Vitro Efficacy of Dalbavancin as a Long-Acting Anti-Biofilm Agent Loaded in Bone Cement.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091445}, pmid = {37760741}, issn = {2079-6382}, support = {PI21/00344//Instituto de Salud Carlos III/ ; FMM21/01//Fundación Mutua Madrileña/ ; FI22/00022//Instituto de Salud Carlos III/ ; MSII18/00008//Instituto de Salud Carlos III/ ; }, abstract = {Based on previous studies by our group in which we demonstrated that dalbavancin loaded in bone cement had good elution capacity for the treatment of biofilm-related periprosthetic infections, we now assess the anti-biofilm activity of dalbavancin and compare it with that of vancomycin over a 3-month period. We designed an in vitro model in which we calculated the percentage reduction in log cfu/mL counts of sonicated steel discs contaminated with staphylococci and further exposed to bone cement discs loaded with 2.5% or 5% vancomycin and dalbavancin at various timepoints (24 h, 48 h, 1 week, 2 weeks, 6 weeks, and 3 months). In addition, we tested the anti-biofilm activity of eluted vancomycin and dalbavancin at each timepoint based on a 96-well plate model in which we assessed the percentage reduction in metabolic activity. We observed a significant decrease in the dalbavancin concentration from 2 weeks of incubation, with sustained anti-biofilm activity up to 3 months. In the case of vancomycin, we observed a significant decrease at 1 week. The concentration gradually increased, leading to significantly lower anti-biofilm activity. The percentage reduction in cfu/mL counts was higher for dalbavancin than for vancomycin at both the 2.5% and the 5% concentrations. The reduction in log cfu/mL counts was higher for S. epidermidis than for S. aureus and was particularly more notable for 5% dalbavancin at 3 months. In addition, the percentage reduction in metabolic activity also decreased at 3 months in 5% dalbavancin and 5% vancomycin, with more notable values recorded for the latter.}, } @article {pmid37760729, year = {2023}, author = {Dornelas-Figueira, LM and Ricomini Filho, AP and Junges, R and Åmdal, HA and Cury, AADB and Petersen, FC}, title = {In Vitro Impact of Fluconazole on Oral Microbial Communities, Bacterial Growth, and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091433}, pmid = {37760729}, issn = {2079-6382}, support = {274867 and 322375//The Research Council of Norway/ ; 306275/2016-3//National Council for Scientific and Technological Development/ ; 88887.369710/2019-00 and 88887.508558/2020-00//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Antifungal agents are widely used to specifically eliminate infections by fungal pathogens. However, the specificity of antifungal agents has been challenged by a few studies demonstrating antibacterial inhibitory effects against Mycobacteria and Streptomyces species. Here, we evaluated for the first time the potential effect of fluconazole, the most clinically used antifungal agent, on a human oral microbiota biofilm model. The results showed that biofilm viability on blood and mitis salivarius agar media was increased over time in the presence of fluconazole at clinically relevant concentrations, despite a reduction in biomass. Targeted PCR revealed a higher abundance of Veillonella atypica, Veillonella dispar, and Lactobacillus spp. in the fluconazole-treated samples compared to the control, while Fusobacterium nucleatum was reduced and Streptococcus spp were not significantly affected. Further, we tested the potential impact of fluconazole using single-species models. Our results, using Streptococcus mutans and Streptococcus mitis luciferase reporters, showed that S. mutans planktonic growth was not significantly affected by fluconazole, whereas for S. mitis, planktonic growth, but not biofilm viability, was inhibited at the highest concentration. Fluconazole's effects on S. mitis biofilm biomass were concentration and time dependent. Exposure for 48 h to the highest concentration of fluconazole was associated with S. mitis biofilms with the most increased biomass. Potential growth inhibitory effects were further tested using four non-streptococcal species. Among these, the planktonic growth of both Escherichia coli and Granulicatella adiacens was inhibited by fluconazole. The data indicate bacterial responses to fluconazole that extend to a broader range of bacterial species than previously anticipated from the literature, with the potential to disturb biofilm communities.}, } @article {pmid37760724, year = {2023}, author = {Michael, CK and Lianou, DT and Tsilipounidaki, K and Gougoulis, DA and Giannoulis, T and Vasileiou, NGC and Mavrogianni, VS and Petinaki, E and Fthenakis, GC}, title = {Recovery of Staphylococci from Teatcups in Milking Parlours in Goat Herds in Greece: Prevalence, Identification, Biofilm Formation, Patterns of Antibiotic Susceptibility, Predictors for Isolation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091428}, pmid = {37760724}, issn = {2079-6382}, abstract = {The objectives of this work are (a) to describe staphylococci on the teatcups of milking parlours in goat farms and identify predictors for the presence of staphylococcal isolates on the teatcups, (b) to evaluate relationships with total bacterial counts and somatic cell counts in bulk-tank milk, and (c) to establish patterns of susceptibility to antibiotics for the staphylococcal isolates and identify predictors for the recovery of resistant isolates. In a cross-sectional study of 66 goat farms across Greece, swab samples were collected from 303 teatcups (upper and lower part) for staphylococcal recovery, identification, and assessment of biofilm formation. Details regarding health management on the farms (including conditions in the milking parlour) and the socio-demographic characteristics of farmers were collected by means of a structured questionnaire. A total of 87 contaminated teatcups (28.7%) were found on 35 goat farms (53.0%). Staphylococci were more frequently recovered from the upper than the lower part of teatcups: 73 versus 43 teatcups, respectively. After identification, 67 staphylococcal isolates (i.e., excluding similar isolates) were recovered from the teatcups; Staphylococcus aureus, Staphylococcus capitis, and Staphylococcus equorum predominated. Of these isolates, 82.1% were biofilm-forming. In multivariable analysis, the annual incidence of clinical mastitis in the herd emerged as the only significant factor associated with the isolation of staphylococci from the teatcups. Of the 67 isolates, 23 (34.3%) were resistant to at least one antibiotic, and 14 (22.4%) were multi-resistant. Resistance was found most commonly against penicillin and ampicillin (22.4% of isolates), fosfomycin (17.9%), clindamycin (14.9%), erythromycin, and tetracycline (13.4%). In multivariable analysis, the annual incidence of clinical mastitis in the herd and the use of detergent for parlour cleaning emerged as significant factors associated with the isolation of staphylococci resistant to antibiotics.}, } @article {pmid37760706, year = {2023}, author = {Batista, S and Fernandez-Pittol, M and Nicolás, LS and Martínez, D and Rubio, M and Garrigo, M and Vila, J and Tudó, G and González-Martin, J}, title = {In Vitro Effect of Three-Antibiotic Combinations plus Potential Antibiofilm Agents against Biofilm-Producing Mycobacterium avium and Mycobacterium intracellulare Clinical Isolates.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091409}, pmid = {37760706}, issn = {2079-6382}, support = {20181610//Fundació La Marató de TV3/ ; PI16/01047, PI2200536//Ministerio de Economía y Competitividad, Instituto de Salud Carlos III cofinanced by European Regional Development Fund (ERDF, FEDER) "A Way to Achieve Europe," the Spanish Ministry of Health/ ; 937-2019//Planes Nacionales de I+D+i 2013-2016, Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía y Competitividad/ ; 2021SGR01569//Sociedad Española de Neumología y Cirugía Torácica (SEPAR), by grant from Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya/ ; }, abstract = {Patients with chronic pulmonary diseases infected by Mycobacterium avium complex (MAC) often develop complications and suffer from treatment failure due to biofilm formation. There is a lack of correlation between in vitro susceptibility tests and the treatment of clinical isolates producing biofilm. We performed susceptibility tests of 10 different three-drug combinations, including two recommended in the guidelines, in biofilm forms of eight MAC clinical isolates. Biofilm developed in the eight isolates following incubation of the inoculum for 3 weeks. Then, the biofilm was treated with three-drug combinations with and without the addition of potential antibiofilm agents (PAAs). Biofilm bactericidal concentrations (BBCs) were determined using the Vizion lector system. All selected drug combinations showed synergistic activity, reducing BBC values compared to those treated with single drugs, but BBC values remained high enough to treat patients. However, with the addition of PAAs, the BBCs steadily decreased, achieving similar values to the combinations in planktonic forms and showing synergistic activity in all the combinations and in both species. In conclusion, three-drug combinations with PAAs showed synergistic activity in biofilm forms of MAC isolates. Our results suggest the need for clinical studies introducing PAAs combined with antibiotics for the treatment of patients with pulmonary diseases infected by MAC.}, } @article {pmid37760705, year = {2023}, author = {Ban-Cucerzan, A and Morar, A and Tîrziu, E and Imre, K}, title = {Evaluation of Antimicrobial Resistance Profiles of Bacteria Isolated from Biofilm in Meat Processing Units.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091408}, pmid = {37760705}, issn = {2079-6382}, support = {ncreasing the impact of excellence research on the capacity for innovation and technology transfer within USAMVB Timișoara" code 6PFE//Government of Romania/ ; }, abstract = {The aim of this study was to assess the hygiene of pork, beef, and poultry carcasses and to determine the phenotypic antibiotic susceptibility of the bacteria embedded in the biofilm formed on the carcasses kept in cooling chambers for at least three days. The level of hygiene was assessed by determining the total aerobic colony count (TACC) and the Enterobacteriaceae level in different sampling points of the carcasses, along with the detection of E. coli and Pseudomonas spp. embedded in the biofilm. Furthermore, the E. coli and Pseudomonas spp. isolates were tested for antimicrobial resistance profiles. A total of 130 samples collected from pork, beef, and poultry from processing units were analyzed to determine the total aerobic colony count as well as to measure the level of Enterobacteriaceae found on the carcasses. The antimicrobial susceptibility of 44 Escherichia coli and eight Pseudomonas spp. strains isolated from the carcasses were assessed using the Vitek 2 system using two different cards. Overall, the regulatory limits for the TACC were exceeded in 7.6% of the samples, and 65% of the samples exceeded the regulatory limits for Enterobacteriaceae levels. The antimicrobial susceptibility tests of the E. coli isolates analyzed with the AST-GN27 card revealed the highest resistance to be that towards ampicillin (76.1%), followed by cefazolin (71.4%), amoxicillin/clavulanic acid (61.9%), nitrofurantoin (52.3%), cefoxitin (47.6%), tetracycline (38.1%), piperacillin, norfloxacin (19%), trimethoprim-sulfamethoxazole (11.9%), cefotaxime (9.5%), ceftazidime, cefazolin, amikacin, gentamicin, and ciprofloxacin (4.7%). However, all of the isolates were sensitive to piperacillin-tazobactam and imipenem. Thirty-two (61.5%; 95% CI 47.9-73.5) out of fifty-two isolates exhibited multidrug resistance, resulting in the expression of 10 resistance profiles. The findings of this study highlight serious hygienic and sanitary deficiencies within the meat processing units and demonstrate that the resulting meat can harbor Multidrug-resistant Escherichia coli and Pseudomonas spp., both of which pose a serious public health risk. However, further research with a larger number of samples is required to reach thorough results.}, } @article {pmid37760700, year = {2023}, author = {Qamer, S and Che-Hamzah, F and Misni, N and Joseph, NMS and Al-Haj, NA and Amin-Nordin, S}, title = {Deploying a Novel Approach to Prepare Silver Nanoparticle Bellamya bengalensis Extract Conjugate Coating on Orthopedic Implant Biomaterial Discs to Prevent Potential Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091403}, pmid = {37760700}, issn = {2079-6382}, abstract = {This study is based on the premise of investigating antibacterial activity through a novel conjugate of silver nanoparticles (AgNPs) and antimicrobial peptides (AMPs) in line with a green synthesis approach by developing antimicrobial-coated implants to prevent bacterial resistance. The AMPs were obtained from Bellamya Bengalensis (BB), a freshwater snail, to prepare the nanocomposite conjugate, e.g., AgNPs@BB extract, by making use of UV-Visible spectroscopy. The antimicrobial assessment of AgNPs@BB extract conjugate was performed using the Resazurin Microtiter Assay Method (REMA), followed by the use of three biocompatible implant materials (titanium alloys, Ti 6AL-4V stainless steel 316L, and polyethylene). Finally, the coating was analyzed under confocal microscopy. The results revealed a significant reduction of biofilm formation on the surfaces of implants coated with conjugate (AgNPs@BB extract) in comparison to uncoated implants. For the MTT assay, no significant changes were recorded for the cells grown on the AgNPs/AMP++ sample in high concentrations. Staphylococcus epidermidis, however, showed more prominent growth on all implants in comparison to Staphylococcus aureus. It is evident from the results that Staphylococcus epidermidis is more susceptible to AgNPs@BB extract, while the minimum inhibitory concentration (MIC) value of AgNPs@BB extract conjugates and biosynthesized AgNPs was also on the higher side. This study indicates that AgNPs@BB extract carries antibacterial activity, and concludes that an excessive concentration of AgNPs@BB extract may affect the improved biocompatibility. This study recommends using robust, retentive, and antimicrobial coatings of AgNPs@BB extract for implantable biocompatible materials in accordance with the novel strategy of biomaterial applications.}, } @article {pmid37760672, year = {2023}, author = {Rana, ML and Firdous, Z and Ferdous, FB and Ullah, MA and Siddique, MP and Rahman, MT}, title = {Antimicrobial Resistance, Biofilm Formation, and Virulence Determinants in Enterococcus faecalis Isolated from Cultured and Wild Fish.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091375}, pmid = {37760672}, issn = {2079-6382}, support = {2022/12/BAU//Bangladesh Agricultural University Research System (BAURES)/ ; }, abstract = {Fish has always been an integral part of Bengali cuisine and economy. Fish could also be a potential reservoir of pathogens. This study aimed to inquisite the distribution of virulence, biofilm formation, and antimicrobial resistance of Enterococcus faecalis isolated from wild and cultivated fish in Bangladesh. A total of 132 koi fish (Anabas scandens) and catfish (Heteropneustes fossilis) were collected from different markets in the Mymensingh district and analyzed to detect E. faecalis. E. faecalis was detected by conventional culture and polymerase chain reaction (PCR), followed by the detection of virulence genes by PCR. Antibiotic susceptibility was determined using the disk diffusion method, and biofilm-forming ability was investigated by crystal violet microtiter plate (CVMP) methods. A total of 47 wild and 40 cultured fish samples were confirmed positive for E. faecalis by PCR. The CVMP method revealed four per cent of isolates from cultured fish as strong biofilm formers, but no strong producers were found from the wild fish. In the PCR test, 45% of the isolates from the wild and cultivated fish samples were found to be positive for at least one biofilm-producing virulence gene, where agg, ace, gelE, pil, and fsrC genes were detected in 80, 95, 100, 93, and 100% of the isolates, respectively. Many of the isolates from both types of samples were multidrug resistant (MDR) (73% in local fish and 100% in cultured fish), with 100% resistance to erythromycin, linezolid, penicillin, and rifampicin in E. faecalis from cultured fish and 73.08, 69.23, 69.23, and 76.92%, respectively, in E. faecalis from wild fish. This study shows that E. faecalis from wild fish have a higher frequency of virulence genes and biofilm-forming genes than cultivated fish. However, compared to wild fish, cultured fish were found to carry E. faecalis that was more highly multidrug resistant. Present findings suggest that both wild and cultured fish could be potential sources for MDR E. faecalis, having potential public health implications.}, } @article {pmid37760668, year = {2023}, author = {Abdo, A and McWhorter, A and Hasse, D and Schmitt-John, T and Richter, K}, title = {Efficacy of Plasma-Treated Water against Salmonella Typhimurium: Antibacterial Activity, Inhibition of Invasion, and Biofilm Disruption.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091371}, pmid = {37760668}, issn = {2079-6382}, support = {Earth and Life Sciences (ALW), grant 834.13.006/NWO_/Dutch Research Council/Netherlands ; }, abstract = {Plasma-treated water (PTW) has emerged as a potential sanitizing agent. This study evaluated antibacterial activity, inhibition of invasion, and biofilm disruption effects of PTW against Salmonella Typhimurium. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined for different PTW types. Time-kill assays were conducted to assess bactericidal effects, while polarized Caco-2 cells were used to evaluate invasion inhibition. Biofilm formation and cell viability were examined following PTW treatment using Salmonella Typhimurium isolates, while biofilm disruption and regrowth prevention were investigated using the Bioflux system. PTW exhibited antibacterial activity against all Salmonella Typhimurium isolates, with MICs of 25% for PTW1 and PTW2, and 50% for PTW3, PTW4, and PTW5. MBCs of 50% in media were observed for all PTW types. Undiluted PTW1 and PTW2 showed the highest bactericidal capacity, significantly reduced Salmonella viability, and completely inhibited bacterial invasion, while PTW3 and PTW5 also showed significant invasion reduction. Bioflux experiments confirmed the eradication of biofilms by PTW1 and PTW2, with no regrowth observed 72 h after PTW was removed. PTW demonstrated significant antibacterial activity, inhibition of invasion, biofilm disruption, and reduction of bacterial viability against Salmonella Typhimurium. This highlights PTW's potential as an effective sanitizer for reducing Salmonella contaminations.}, } @article {pmid37760662, year = {2023}, author = {Natsheh, IY and Elkhader, MT and Al-Bakheit, AA and Alsaleh, MM and El-Eswed, BI and Hosein, NF and Albadawi, DK}, title = {Inhibition of Acinetobacter baumannii Biofilm Formation Using Different Treatments of Silica Nanoparticles.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, doi = {10.3390/antibiotics12091365}, pmid = {37760662}, issn = {2079-6382}, abstract = {There exists a multitude of pathogens that pose a threat to human and public healthcare, collectively referred to as ESKAPE pathogens. These pathogens are capable of producing biofilm, which proves to be quite resistant to elimination. Strains of A. baumannii, identified by the "A" in the acronym ESKAPE, exhibit significant resistance to amoxicillin in vivo due to their ability to form biofilm. This study aims to inhibit bacterial biofilm formation, evaluate novel silica nanoparticles' effectiveness in inhibiting biofilm, and compare their effectiveness. Amoxicillin was utilized as a positive control, with a concentration exceeding twice that when combined with silica NPs. Treatments included pure silica NPs, silica NPs modified with copper oxide (CuO.SiO2), sodium hydroxide (NaOH.SiO2), and phosphoric acid (H3PO4.SiO2). The characterization of NPs was conducted using scanning electron microscopy (SEM), while safety testing against normal fibroblast cells was employed by MTT assay. The microtiter plate biofilm formation assay was utilized to construct biofilm, with evaluations conducted using three broth media types: brain heart infusion (BHI) with 2% glucose and 2% sucrose, Loria broth (LB) with and without glucose and sucrose, and Dulbecco's modified eagle medium/nutrient (DMEN/M). Concentrations ranging from 1.0 mg/mL to 0.06 µg/mL were tested using a microdilution assay. Results from SEM showed that pure silica NPs were mesoporous, but in the amorphous shape of the CuO and NaOH treatments, these pores were disrupted, while H3PO4 was composed of sheets. Silica NPs were able to target Acinetobacter biofilms without harming normal cells, with viability rates ranging from 61-73%. The best biofilm formation was achieved using a BHI medium with sugar supplementation, with an absorbance value of 0.35. Biofilms treated with 5.0 mg/mL of amoxicillin as a positive control alongside 1.0 mg/mL of each of the four silica treatments in isolation, resulting in the inhibition of absorbance values of 0.04, 0.13, 0.07, 0.09, and 0.08, for SiO2, CuO.SiO2, NaOH.SiO2 and H3PO4.SiO2, respectively. When amoxicillin was combined, inhibition increased from 0.3 to 0.04; NaOH with amoxicillin resulted in the lowest minimum biofilm inhibitory concentration (MBIC), 0.25 µg/mL, compared to all treatments and amoxicillin, whereas pure silica and composite had the highest MBIC, even when combined with amoxicillin, compared to all treatments, but performed better than that of the amoxicillin alone which gave the MBIC at 625 µg/mL. The absorbance values of MBIC of each treatment showed no significant differences in relation to amoxicillin absorbance value and relation to each other. Our study showed that smaller amoxicillin doses combined with the novel silica nanoparticles may reduce toxic side effects and inhibit biofilm formation, making them viable alternatives to high-concentration dosages. Further investigation is needed to evaluate in vivo activity.}, } @article {pmid37760162, year = {2023}, author = {Wang, Y and Gao, H and Chang, L and Xu, J and Zhou, X and Zhang, C and Peng, Q}, title = {Efficient Removal of Dental Plaque Biofilm from Training Typodont Teeth via Water Flosser.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, doi = {10.3390/bioengineering10091061}, pmid = {37760162}, issn = {2306-5354}, support = {81973261//National Natural Science Foundation of China/ ; }, abstract = {Plaque biofilms play critical roles in the development of dental caries. Mechanical plaque control methods are considered to be most effective for plaque removal, such as brushing teeth or using flosser. Recently, water flosser has been paid much attention. Here, we tested the ability of a water flosser to remove the adhered sucrose and the dental plaque biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Actinobacillus viscosus. We found that the residual sucrose concentration was 3.54 mg/mL in the control group, 1.75 mg/mL in the syringe group (simulating the ordinary mouthwash), and 0 mg/mL in water flosser group. In addition, the residual bacterial concentration was 3.6 × 10[8] CFU/mL in the control group, 1.6 × 10[7] CFU/mL in the syringe group, and only 5.5 × 10[5] CFU/mL in the water flosser group. In summary, water flosser is effective for cleaning the teeth, which may have significant potential in preventing dental caries and maintaining oral health.}, } @article {pmid37759692, year = {2023}, author = {Habib, T and Rahman, A and Nair, AB and Islam, SMS}, title = {Application of Three Compounds Extracted from Cynodon dactylon against Streptococcus mutans Biofilm Formation to Prevent Oral Diseases.}, journal = {Biomolecules}, volume = {13}, number = {9}, pages = {}, doi = {10.3390/biom13091292}, pmid = {37759692}, issn = {2218-273X}, support = {GRANT 3236//KIng Faisal University/ ; }, abstract = {Streptococcus mutans bacteria form a biofilm called plaque that causes oral diseases, including tooth decay. Therefore, inhibition of biofilm formation is essential to maintaining good oral health. The health and nutritional benefits of Cynodon dactylon are well documented, but very little is known about its use to treat against oral diseases. The aim of this study was to detect the adhesion strength of the S. mutans bacterial biofilm in 100 cases in the Rajshahi region and evaluate the inhibitory activity of different compound extracts of C. dactylon on the S. mutans bacterial biofilm by determining the composition of isolated compounds using phytochemical analysis. Nuclear magnetic resonance (NMR) spectroscopy confirmed that three specific compounds from C. dactylon were discovered in this study: 3,7,11,15 tetramethyl hexadec-2-4dien 1-o1, compound 3,7,11,15 tetramethylhexadec-2-en-1-o1 from phytol derivatives, and stigmasterol. Results indicated that the compound of 3,7,11,15-tetramethyl-hexadec-2-en-1-ol exhibited higher antibiofilm activities on S. mutans than those of the other compound extracts. A lower level of minimum inhibitory concentration was exposed by 3, 7, 11,15 tetramethyl hexadeca-2-en-1-o1 (T2) on S. mutans at 12.5 mL. In this case, the compound of 3,7,11,15 tetramethyl hexadec 2en-1-o1 was used, and patients showed a mean value and standard error reduced from 3.42 ± 0.21 to 0.33 ± 0.06 nm. The maximum inhibition was (80.10%) in the case of patient no. 17, with a value of p < 0.05 found for S. mutans to which 12.5 μL/mL ethyl acetate extract was applied. From these findings, it may be concluded that C. dactylon extracts can be incorporated into various oral preparations to prevent tooth decay.}, } @article {pmid37756166, year = {2023}, author = {Greenwich, JL and Fleming, D and Banin, E and Häussler, S and Kjellerup, BV and Sauer, K and Visick, KL and Fuqua, C}, title = {The biofilm community resurfaces: new findings and post-pandemic progress.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0016623}, doi = {10.1128/jb.00166-23}, pmid = {37756166}, issn = {1098-5530}, abstract = {The ninth American Society for Microbiology Conference on Biofilms was convened in-person on 13-17 November 2022 in Charlotte, NC. As the first of these conferences since prior to the start of the COVID-19 pandemic, the energy among the participants of the conference was clear, and the meeting was a tremendous success. The mixture of >330 oral and poster presentations resoundingly embodied the vitality of biofilm research across a wide range of topics and multiple scientific disciplines. Special activities, including a pre-conference symposium for early career researchers, further enhanced the attendee experience. As a general theme, the conference was deliberately structured to provide high levels of participation and engagement among early career scientists.}, } @article {pmid37755996, year = {2023}, author = {Zhang, H and Zhang, Z and Li, J and Qin, G}, title = {New Strategies for Biocontrol of Bacterial Toxins and Virulence: Focusing on Quorum-Sensing Interference and Biofilm Inhibition.}, journal = {Toxins}, volume = {15}, number = {9}, pages = {}, doi = {10.3390/toxins15090570}, pmid = {37755996}, issn = {2072-6651}, support = {No. 31802111//National Natural Science Foundation of China/ ; }, abstract = {The overuse of antibiotics and the emergence of multiple-antibiotic-resistant pathogens are becoming a serious threat to health security and the economy. Reducing antimicrobial resistance requires replacing antibiotic consumption with more biocontrol strategies to improve the immunity of animals and humans. Probiotics and medicinal plants have been used as alternative treatments or preventative therapies for a variety of diseases caused by bacterial infections. Therefore, we reviewed some of the anti-virulence and bacterial toxin-inhibiting strategies that are currently being developed; this review covers strategies focused on quenching pathogen quorum sensing (QS) systems, the disruption of biofilm formation and bacterial toxin neutralization. It highlights the probable mechanism of action for probiotics and medicinal plants. Although further research is needed before a definitive statement can be made on the efficacy of any of these interventions, the current literature offers new hope and a new tool in the arsenal in the fight against bacterial virulence factors and bacterial toxins.}, } @article {pmid37755512, year = {2023}, author = {Peters, MK and Astafyeva, Y and Han, Y and Macdonald, JFH and Indenbirken, D and Nakel, J and Virdi, S and Westhoff, G and Streit, WR and Krohn, I}, title = {Novel marine metalloprotease-new approaches for inhibition of biofilm formation of Stenotrophomonas maltophilia.}, journal = {Applied microbiology and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37755512}, issn = {1432-0614}, support = {SuReMetS (FKZ 031B0944A)//Bundesministerium für Bildung und Forschung/ ; AquaHealth (FKZ 031B0945C)//Bundesministerium für Bildung und Forschung/ ; MarBioTech (FKZ 031A565)//Bundesministerium für Bildung und Forschung/ ; }, abstract = {Many marine organisms produce bioactive molecules with unique characteristics to survive in their ecological niches. These enzymes can be applied in biotechnological processes and in the medical sector to replace aggressive chemicals that are harmful to the environment. Especially in the human health sector, there is a need for new approaches to fight against pathogens like Stenotrophomonas maltophilia which forms thick biofilms on artificial joints or catheters and causes serious diseases. Our approach was to use enrichment cultures of five marine resources that underwent sequence-based screenings in combination with deep omics analyses in order to identify enzymes with antibiofilm characteristics. Especially the supernatant of the enrichment culture of a stony coral caused a 40% reduction of S. maltophilia biofilm formation. In the presence of the supernatant, our transcriptome dataset showed a clear stress response (upregulation of transcripts for metal resistance, antitoxins, transporter, and iron acquisition) to the treatment. Further investigation of the enrichment culture metagenome and proteome indicated a series of potential antimicrobial enzymes. We found an impressive group of metalloproteases in the proteome of the supernatant that is responsible for the detected anti-biofilm effect against S. maltophilia. KEY POINTS: • Omics-based discovery of novel marine-derived antimicrobials for human health management by inhibition of S. maltophilia • Up to 40% reduction of S. maltophilia biofilm formation by the use of marine-derived samples • Metalloprotease candidates prevent biofilm formation of S. maltophilia K279a by up to 20.}, } @article {pmid37754547, year = {2023}, author = {Pan, S and Erdmann, M and Terrell, J and Cabeen, MT}, title = {A putative lipase affects Pseudomonas aeruginosa biofilm matrix production.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0037423}, doi = {10.1128/msphere.00374-23}, pmid = {37754547}, issn = {2379-5042}, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that is widely known for infecting patients with underlying conditions. This species often survives antibiotic therapy by forming biofilms, in which the cells produce a protective extracellular matrix. P. aeruginosa also produces virulence factors that enhance its ability to cause disease. One signaling pathway that influences virulence is the nitrogen-related phosphotransferase system (Nitro-PTS), which consists of an initial phosphotransferase, PtsP, a phosphocarrier, PtsO, and a terminal phosphate receptor, PtsN. The physiological role of the Nitro-PTS in P. aeruginosa is poorly understood. However, PtsN, when deprived of its upstream phosphotransfer proteins, has an antagonistic effect on biofilm formation. We thus conducted a transposon mutagenesis screen in an unphosphorylated-PtsN (i.e., ∆ptsP) background to identify downstream proteins with unacknowledged roles in PtsN-mediated biofilm suppression. We found an unstudied gene, PA14_04030, whose disruption restored biofilm production. This gene encodes a predicted phospholipase with signature alpha/beta hydrolase folds and a lipase signature motif with an active-site Ser residue. Hence, we renamed the gene bipL, for biofilm-impacting phospholipase. Deletion of bipL in a ∆ptsP background increased biofilm formation, supporting the idea that BipL is responsible for reducing biofilm formation in strains with unphosphorylated PtsN. Moreover, substituting the putative catalytic Ser for Ala phenocopied bipL deletion, indicating that this residue is important for the biofilm-suppressive activity of BipL in vivo. As our preliminary data suggest that BipL is a lipase, we performed lipidomics to detect changes in the lipid profile due to bipL deletion and found changes in some lipid species. IMPORTANCE Biofilm formation by bacteria occurs when cells secrete an extracellular matrix that holds them together and shields them from environmental insults. Biofilms of bacterial opportunistic human pathogens such as Pseudomonas aeruginosa pose a substantial challenge to clinical antimicrobial therapy. Hence, a more complete knowledge about the bacterial factors that influence and regulate production of the biofilm matrix is one key to formulate more effective therapeutic strategies. In this study, we screen for factors that are important for reducing biofilm matrix production in certain genetic backgrounds. We unexpectedly found a gene encoding a putative lipase enzyme and showed that its predicted catalytic site is important for its ability to reduce biofilm formation. Our findings suggest that lipase enzymes have previously uncharacterized functions in biofilm matrix regulation.}, } @article {pmid37752756, year = {2023}, author = {Luo, Z and Shi, T and Ruan, Z and Ding, C and Huang, R and Wang, W and Guo, Z and Zhan, Z and Zhang, Y and Chen, Y}, title = {Quorum Sensing Interference Assisted Therapy-Based Magnetic Hyperthermia Amplifier for Synergistic Biofilm Treatment.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2304836}, doi = {10.1002/smll.202304836}, pmid = {37752756}, issn = {1613-6829}, support = {81974340//National Natural Science Foundation of China/ ; 82172455//National Natural Science Foundation of China/ ; YG2021ZD22//Interdisciplinary Program of Shanghai Jiao Tong University/ ; 22S31900200//Shanghai Science and Technology Innovation Action Plan Program/ ; SHDC12021117//Shanghai Shenkang Hospital Development Center Clinical Innovation/ ; 2023M732289//China Postdoctoral Science Foundation/ ; }, abstract = {Biofilms offer bacteria a physical and metabolic barrier, enhancing their tolerance to external stress. Consequently, these biofilms limit the effectiveness of conventional antimicrobial treatment. Recently, quorum sensing (QS) has been linked to biofilm's stress response to thermal, oxidative, and osmotic stress. Herein, a multiple synergistic therapeutic strategy that couples quorum sensing interference assisted therapy (QSIAT)-mediated enhanced thermal therapy with bacteria-triggered immunomodulation in a single nanoplatform, is presented. First, as magnetic hyperthermia amplifier, hyaluronic acid-coated ferrite (HA@MnFe2 O4) attenuates the stress response of biofilm by down-regulating QS-related genes, including agrA, agrC, and hld. Next, the sensitized bacteria are eliminated with magnetic heat. QS interference and heat also destruct the biofilm, and provide channels for further penetration of nanoparticles. Moreover, triggered by bacterial hyaluronidase, the wrapped hyaluronic acid (HA) decomposes into disaccharides at the site of infection and exerts healing effect. Thus, by reversing the bacterial tissue invasion mechanism for antimicrobial purpose, tissue regeneration following pathogen invasion and thermal therapy is successfully attained. RNA-sequencing demonstrates the QS-mediated stress response impairment. In vitro and in vivo experiments reveal the excellent antibiofilm and anti-inflammatory effects of HA@MnFe2 O4 . Overall, QSIAT provides a universal enhancement strategy for amplifying the bactericidal effects of conventional therapy via stress response interference.}, } @article {pmid37750674, year = {2023}, author = {Vincy, A and Gaikwad, Y and Agarwal, H and Jain, N and Vankayala, R}, title = {A Label-Free and Ultrasensitive Prussian Blue-Based Dipstick Sensor for Bacterial and Biofilm Detection.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.langmuir.3c01451}, pmid = {37750674}, issn = {1520-5827}, abstract = {Water and food contamination has become the major contributor to infections and deaths. However, rapid and sensitive bacterial detection still remains an unmet demand that has attracted widespread attention. Often water and food samples are sent out for laboratory testing to detect the presence of contamination, which is time-consuming and laborious. Herein, we have developed a highly sensitive, tenable, affordable, and robust (STAR) paper-based colorimetric dipstick sensor based on the principle of Prussian blue (PB) synthesis as an indicator of bacterial contamination. In the presence of bacteria, it leads to the formation of PB, a dye that acts as a colorimetric indicator. The intensity of the PB is the direct measure of the degree of contamination. The fabrication of the STAR dipstick sensor involves a simple and cost-effective process. The STAR dipstick sensor is ultrasensitive and can detect up to 10[1] CFU/mL of bacteria within minutes of contact with the test sample. The STAR dipstick sensor is fabricated using biodegradable components, which is speculated to facilitate quick and environmentally friendly degradation after each use. The sensor has been validated for its properties and capabilities at different pH to detect both Gram-positive and Gram-negative bacterial strains in real-time samples. The stability and degradation were also monitored. Comprehensively, the proposed STAR dipstick sensor can serve as a point-of-care device to detect bacterial contamination in a swift and sensitive manner.}, } @article {pmid37748596, year = {2023}, author = {Song, Y and Sun, M and Mu, G and Tuo, Y}, title = {Exopolysaccharide produced by Lactiplantibacillus plantarum Y12 exhibits inhibitory effect on the Shigella flexneri genes expression related to biofilm formation.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {127048}, doi = {10.1016/j.ijbiomac.2023.127048}, pmid = {37748596}, issn = {1879-0003}, abstract = {Shigella is a specific enteric pathogen in humans, causing symptoms of bacterial dysentery. The biofilm formation of S. flexneri contributes to the emergence of multidrug resistance and facilitates the establishment of persistent chronic infections. This study investigated the regulatory effects of Lactiplantibacillus plantarum Y12 exopolysaccharide (L-EPS) on gene expression and its spatial hindrance effects in inhibiting the biofilm formation of S. flexneri. The transcriptome analysis revealed a significant impact of L-EPS on the gene expression profile of S. flexneri, with a total of 968 genes showing significant changes (507 up-regulated and 461 down-regulated). The significantly down-regulated KEGG metabolic pathway enriched in phosphotransferase system, Embden-Meyerhf-Parnas, Citrate cycle, Lipopolysaccharide biosynthesis, Cationic antimicrobial peptide resistance, Two-component system. Moreover, L-EPS significantly down-regulated the gene expression levels of fimbriae synthesis (fimF), lipopolysaccharide synthesis (lptE, lptB), anchor protein repeat domain (arpA), virulence factor (lpp, yqgB), antibiotic resistance (marR, cusB, mdtL, mdlB), heavy metal resistance (zraP), and polysaccharide synthesis (mtgA, mdoB, mdoC). The expression of biofilm regulator factor (bssS) and two-component system suppressor factor (mgrB) were significantly up-regulated. The RT-qPCR results indicated that a major component of L-EPS (L-EPS 2-1) exhibited the gene regulatory effect on the S. flexneri biofilm formation. Furthermore, electrophoresis and isothermal microtitration calorimetry demonstrated that the interaction between L-EPS 2-1 and eDNA is electrostatic dependent on the change in environmental pH, disrupting the stable spatial structure of S. flexneri biofilm. In conclusion, L-EPS inhibited the biofilm formation of S. flexneri through gene regulation and spatial obstruction effects.}, } @article {pmid37748387, year = {2023}, author = {Gómez, AC and Horgan, C and Yero, D and Bravo, M and Daura, X and O'Driscoll, M and Gibert, I and O'Sullivan, TP}, title = {Synthesis and evaluation of aromatic BDSF bioisosteres on biofilm formation and colistin sensitivity in pathogenic bacteria.}, journal = {European journal of medicinal chemistry}, volume = {261}, number = {}, pages = {115819}, doi = {10.1016/j.ejmech.2023.115819}, pmid = {37748387}, issn = {1768-3254}, abstract = {The diffusible signal factor family (DSF) of molecules play an important role in regulating intercellular communication, or quorum sensing, in several disease-causing bacteria. These messenger molecules, which are comprised of cis-unsaturated fatty acids, are involved in the regulation of biofilm formation, antibiotic tolerance, virulence and the control of bacterial resistance. We have previously demonstrated how olefinic N-acyl sulfonamide bioisosteric analogues of diffusible signal factor can reduce biofilm formation or enhance antibiotic sensitivity in a number of bacterial strains. This work describes the design and synthesis of a second generation of aromatic N-acyl sulfonamide bioisosteres. The impact of these compounds on biofilm production in Acinetobacter baumannii, Escherichia coli, Burkholderia multivorans, Burkholderia cepacia, Burkholderia cenocepacia, Pseudomonas aeruginosa and Stenotrophomonas maltophilia is evaluated, in addition to their effects on antibiotic tolerance. The ability of these molecules to increase survival rates on co-administration with colistin is also investigated using the Galleria infection model.}, } @article {pmid37748343, year = {2023}, author = {Song, Z and Liao, R and Zhang, X and Su, X and Wang, M and Zeng, H and Dong, W and Sun, F}, title = {Simultaneous methanogenesis and denitrification in an anaerobic moving bed biofilm reactor for landfill leachate treatment: Ameliorative effect of rhamnolipids.}, journal = {Water research}, volume = {245}, number = {}, pages = {120646}, doi = {10.1016/j.watres.2023.120646}, pmid = {37748343}, issn = {1879-2448}, abstract = {In this study, an anaerobic moving bed biofilm reactor (AnMBBR) was developed for simultaneous methanogenesis and denitrification (SMD) to treat high-strength landfill leachate for the first time. A novel strategy using biosurfactant to ameliorate the inhibition of landfill leachate on the SMD performance was proposed and the underlying mechanisms were explored comprehensively. With the help of rhamnolipids, the chemical oxygen demand (COD) removal efficiency of landfill leachate was improved from 86.0% ± 2.9% to 97.5% ± 1.6%, while methane yields increased from 50.1 mL/g-COD to 69.6 mL/g-COD, and the removal efficiency of NO3[-]-N was also slightly increased from 92.5% ± 1.9% to 95.6% ± 1.0%. The addition of rhamnolipids increased the number of live cells and enhanced the secretion of extracellular polymeric substances (EPS) and key enzyme activity, indicating that the inhibitory effect was significantly ameliorated. Methanogenic and denitrifying bacteria were enhanced by 1.6 and 1.1 times, respectively. Analysis of the microbial metabolic pathways demonstrated that landfill leachate inhibited the expression of genes involved in methanogenesis and denitrification, and that their relative abundance could be upregulated with the assistance of rhamnolipids addition. Moreover, extended Deraguin - Landau - Verwery - Oxerbeek (XDLVO) theory analysis indicated that rhamnolipids reduced the repulsive interaction between biofilms and pollutants with a 57.0% decrease in the energy barrier, and thus accelerated the adsorption and uptake of pollutants onto biofilm biomass. This finding provides a low-carbon biological treatment protocol for landfill leachate and a reliable and effective strategy for its sustainable application.}, } @article {pmid37747474, year = {2023}, author = {Kuang, H and Bi, H and Li, X and Lv, X and Liu, Y}, title = {Inhibition of S. aureus biofilm formation by linezolid alleviates sepsis-induced lung injury caused by S. aureus infection through direct inhibition of icaA activity.}, journal = {The new microbiologica}, volume = {46}, number = {3}, pages = {285-295}, pmid = {37747474}, issn = {1121-7138}, abstract = {Antibiotic-resistant S. aureus infections can be life-threatening. Linezolid is known to hinder S. aureus biofilm formation, but the underlying molecular mechanism remains unclear. Molecular docking revealed that linezolid can bind to icaA, and this was confirmed by thermal drift assays. Linezolid demonstrated a dose-dependent inhibition of icaA enzyme activity. Mutating Trp267, a key residue identified through molecular docking, significantly decreased linezolid binding and inhibitory effects on mutant icaA activity. However, the mutant icaA Trp267Ala showed only slight activity reduction compared to icaA. Linezolid had minimal impact on icaB's thermal stability and activity. The 50S ribosomal L3ΔSer145 mutant S. aureus exhibited similar growth and biofilm formation to the wild-type strain. Linezolid effectively suppressed the growth and biofilm formation of wildtype S. aureus. Although linezolid lost its ability to inhibit the growth of the mutant strain, it still effectively hindered its biofilm formation. Linezolid exhibited weaker attenuation of sepsis-induced lung injury caused by 50S ribosomal L3ΔSer145 mutant S. aureus compared to wild-type S. aureus. These findings indicate that linezolid hampers S. aureus biofilm formation by directly inhibiting icaA activity, independently of its impact on bacterial growth.}, } @article {pmid37747470, year = {2023}, author = {Du, Z and Han, J and Luo, J and Bi, G and Liu, T and Kong, J and Chen, Y}, title = {Combination effects of baicalin with linezolid against Staphylococcus aureus biofilm-related infections: in vivo animal model.}, journal = {The new microbiologica}, volume = {46}, number = {3}, pages = {258-263}, pmid = {37747470}, issn = {1121-7138}, abstract = {Staphylococcus aureus is a gram-positive bacterium that can produce biofilm, and biofilm-associated infections are difficult to control. Biofilm prevents antibiotics from penetrating and killing the bacteria. Combined use of antimicrobials is a common strategy to treat S. aureus biofilm-related infections. In this in vivo study, the clinically isolated strain of S. aureus 17546 (t037) was selected to establish a biofilm-associated infection rat model, and baicalin and linezolid were used to treat the infection. CFU counting was used to determine the bacteria within the biofilm, the biofilm structure was viewed using scanning electron microscopy (SEM), histopathology was performed, and inflammatory factors were analyzed by ELISA. Baicalin was efficient in destroying the biofilm and exerted a synergistic bactericidal effect when combined with linezolid. Based on these findings, baicalin combined with linezolid may be efficacious in controlling S. aureus biofilm-related infections.}, } @article {pmid37747238, year = {2023}, author = {Zhou, Y and Liu, Z and Wen, J and Zhou, Y and Lin, H}, title = {The inhibitory effect of berberine chloride hydrate on Streptococcus mutans biofilm formation at different pH values.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0217023}, doi = {10.1128/spectrum.02170-23}, pmid = {37747238}, issn = {2165-0497}, abstract = {Streptococcus mutans (S. mutans) is one of the major cariogenic bacteria of dental caries owing to its ability to adhere to tooth surfaces and biofilm formation. Berberine chloride hydrate (BH), a quaternary ammonium salt alkaloid, has diverse pharmacological efforts against microorganisms. However, the effect of BH on S. mutans biofilm has not been reported. Considering that berberine is a quaternary ammonium salt alkaloid, which needs to adapt to a large variation in pH values and the acid resistance of S. mutans, we employed three groups including pH 5 (acidic), pH 8 (alkaline), and unprocessed group (neutral) to examine the antibiofilm activities of BH against S. mutans during different pH values. In this study, we found BH effectively suppresses S. mutans biofilm formation as well as its cariogenic virulence including acid production and EPS synthesis significantly, and the inhibitory effort was reduced under acidic condition whereas elevated under alkaline condition. In addition, we preliminarily explored the influence of pH values on the structural stability and biosafety of BHas well as the underlying mechanism of inhibition of S. mutans biofilm formation with BH. Our study showed BH could maintain a good structural stability and low toxicity to erythrocytes at different pH values. And BH could downregulate the expression of srtA, spaP, and gbpC, which play critical roles in the adhesion process, promoting bacterial colonization and biofilm formation. Furthermore, comX and ldh expression levels were downregulated in BH-treated group, which might explain its inhibitory effect on acid production.IMPORTANCEDental caries is a common chronic detrimental disease, which could cause a series of oral problem including oral pain, difficulties in eating, and so on. Recently, many natural products have been considered as fundamental sources of therapeutic drugs to prevent caries. Berberine as a plant extract showed good antibiofilm abilities against microorganism. Our study focuses on its antibiofilm abilities against S. mutans, which was defined as major cariogenic bacterium and explored the role of pH values and possible underlying mechanisms in the inhibitory effect of BH on S. mutans biofilm formation. This study demonstrated a promising prospect for BH as an adjuvant drug in the prevention and management of dental caries.}, } @article {pmid37746691, year = {2023}, author = {Mugge, RL and Rakocinski, CF and Woolsey, M and Hamdan, LJ}, title = {Proximity to built structures on the seabed promotes biofilm development and diversity.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-13}, doi = {10.1080/08927014.2023.2255141}, pmid = {37746691}, issn = {1029-2454}, abstract = {The rapidly expanding built environment in the northern Gulf of Mexico includes thousands of human built structures (e.g. platforms, shipwrecks) on the seabed. Primary-colonizing microbial biofilms transform structures into artificial reefs capable of supporting biodiversity, yet little is known about formation and recruitment of biofilms. Short-term seafloor experiments containing steel surfaces were placed near six structures, including historic shipwrecks and modern decommissioned energy platforms. Biofilms were analyzed for changes in phylogenetic composition, richness, and diversity relative to proximity to the structures. The biofilm core microbiome was primarily composed of iron-oxidizing Mariprofundus, sulfur-oxidizing Sulfurimonas, and biofilm-forming Rhodobacteraceae. Alpha diversity and richness significantly declined as a function of distance from structures. This study explores how built structures influence marine biofilms and contributes knowledge on how anthropogenic activity impacts microbiomes on the seabed.}, } @article {pmid37744914, year = {2023}, author = {Li, Y and Ni, M}, title = {Regulation of biofilm formation in Klebsiella pneumoniae.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1238482}, pmid = {37744914}, issn = {1664-302X}, abstract = {Klebsiella pneumoniae is an important Gram-negative opportunistic pathogen that is responsible for a variety of nosocomial and community-acquired infections. Klebsiella pneumoniae has become a major public health issue owing to the rapid global spread of extensively-drug resistant (XDR) and hypervirulent strains. Biofilm formation is an important virulence trait of K. pneumoniae. A biofilm is an aggregate of microorganisms attached to an inert or living surface by a self-produced exo-polymeric matrix that includes proteins, polysaccharides and extracellular DNA. Bacteria within the biofilm are shielded from antibiotics treatments and host immune responses, making it more difficult to eradicate K. pneumoniae-induced infection. However, the detailed mechanisms of biofilm formation in K. pneumoniae are still not clear. Here, we review the factors involved in the biofilm formation of K. pneumoniae, which might provide new clues to address this clinical challenge.}, } @article {pmid37743308, year = {2023}, author = {Shui, J and Luo, L and Xiang, YG and Shi, GM and Wu, JL and Pan, JH}, title = {[Analysis of biofilm-forming ability and drug resistance for Hypervirulent Klebsiella pneumoniae].}, journal = {Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]}, volume = {57}, number = {9}, pages = {1452-1457}, doi = {10.3760/cma.j.cn112150-20220929-00938}, pmid = {37743308}, issn = {0253-9624}, support = {2021JJ40624//Natural Science Foundation of Hunan Province/ ; D202311006014, 202111000032//Medical Scientific Research Project of Hunan Health Commission/ ; kq2004166//Changsha Municipal Science and Technology Project/ ; }, abstract = {Investigate the biofilm-forming ability and drug resistance of Hypervirulent Klebsiella pneumoniae (HvKP) to provide scientific basis for the treatment of HvKP-infection. A total of 96 Klebsiella pneumoniae strains isolated from clinical infection specimens in Changsha Central Hospital from January to December in 2021 were retrospectively collected, and the clinical data of patients were collected. The string test preliminarily distinguished between HvKP and classic Klebsiella pneumoniae (CKP). The biofilm-forming ability of clinical strains of Klebsiella pneumoniae (KP) was determined by microplate method. The Vitek 2 Compact automatic microbial identification/drug sensitivity analysis system was used for bacterial identification and drug sensitivity test. The clinical data of patients, biofilm forming ability and drug resistance in the HvKP group and those in the CKP group were compared and analyzed. The results showed that a total of 20 strains of HvKP were isolated from 96 non-repetitive KP, and the detection rate was 20.8%. HvKP mainly come from respiratory specimens, up to 75.0%.The prevalence of hepatobiliary diseases and the infection rate of multiple sites in patients with HvKP infection were higher than those in patients with CKP infection, and the difference was statistically significant(χ[2]=5.184,7.488;P=0.023,0.006).There was no significant difference between the two groups in terms of gender, age, ICU admission, hypertension, diabetes, coronary heart disease, lung disease, urinary system disease, central nervous system disease and laboratory test indexes (all P>0.05).17 (85.0%) strains of HvKP can form biofilm, including 2 strains with weak biofilm-forming ability (10.0%), 10 strains with moderate biofilm-forming ability (50.0%) and 5 strains with strong biofilm-forming ability (25.0%). Among the 76 CKP, 71 (93.4%) could form biofilm, including 13 (17.1%) with weak biofilm-forming ability, 30(39.5%) with moderate biofilm-forming ability and 28 (36.8%) with strong biofilm-forming ability. There was no significant difference in biofilm-forming ability between HvKP and CKP (χ[2]=1.470,P=0.225).The overall resistance rate of HvKP was not high, but a multi-resistant HvKP resistant to carbapenems was found. The detection rate of multi-resistant HvKP (5.0%) was lower than that of multi-resistant CKP (28.9%), and the difference was statistically significant (χ[2]=4.984, P=0.026).The resistance rate of HvKP to piperacillin/tazobactam, aztreonam, ciprofloxacin, levofloxacin, ceftazidime, cefepime, tobramycin, minocycline, doxycycline, and compound sulfamethoxazole was lower than that of CKP, and the difference was statistically significant (all P<0.05). In conclusion, most of hypervirulent Klebsiella pneumoniae can form biofilm in this study, but the difference of biofilm-forming ability is not obvious compared with classic Klebsiella pneumoniae. HvKP maintains high sensitivity to commonly used antibacterial drugs, but the drug resistance monitoring of the bacteria cannot be ignored.}, } @article {pmid37743027, year = {2023}, author = {Wu, K and Zhang, T and Chai, X and Wang, P and Duan, X and He, D and Zou, D}, title = {Study on the formation and anti-biofilm properties of cinnamon essential oil inclusion complexes by the structure of modified β-cyclodextrins.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106361}, doi = {10.1016/j.micpath.2023.106361}, pmid = {37743027}, issn = {1096-1208}, abstract = {Essential oils (EOs), which are plant-oriented anti-biofilm agents, are extensively encapsulated by cyclodextrins to overcome their aqueous solubility and chemical instability, and achieve slow release during long-term storage. However, the biological activities of EOs decreased after initial encapsulation in CDs. In this study, modified-β-cyclodextrins (β-CDs) were screened as wall materials to maintained the initial anti-biofilm effect of pure CEO. The inhibitory and bactericidal activities of CEO encapsulated in five types of β-CDs with different substituents (primary hydroxyl, maltosyl, hydroxypropyl, methyl, and carboxymethyl) against Staphylococcus aureus biofilm were evaluated. Crystal violet assay and 3D-View observations suggested that CEO and its inclusion complexes (CEO-ICs) inhibited Staphylococcus aureus biofilm formation through the inhibition of colonising spreading, exopolysaccharide synthesis, and cell surface properties. Molecular docking revealed the causes of the decrease in the anti-biofilm effect after encapsulation, and quantitative structure-activity relationship assays provided MIC and MBIC prediction equation for modified-β-cyclodextrins inclusion complexes. Maltosyl-β-CD was screened as the best wall material to retained the anti-biofilm activities as pure cinnamon essential oil in initial stage, and its inclusion complexes can effectively inhibited biofilm formation in milk. This study provides a theoretical guidance for the selection β-CDs to encapsulate CEO as plant-oriented anti-biofilm agents to inhibit bacterial biofilm formation.}, } @article {pmid37742949, year = {2023}, author = {Chi, Z and Liu, X and Li, H and Liang, S and Luo, YH and Zhou, C and Rittmann, BE}, title = {Co-metabolic biodegradation of chlorinated ethene in an oxygen- and ethane-based membrane biofilm reactor.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167323}, doi = {10.1016/j.scitotenv.2023.167323}, pmid = {37742949}, issn = {1879-1026}, abstract = {Groundwater contamination by chlorinated ethenes is an urgent concern worldwide. One approach for detoxifying chlorinated ethenes is aerobic co-metabilims using ethane (C2H6) as the primary substrate. This study evaluated long-term continuous biodegradation of three chlorinated alkenes in a membrane biofilm reactor (MBfR) that delivered C2H6 and O2 via gas-transfer membranes. During 133 days of continuous operation, removals of dichloroethane (DCE), trichloroethene (TCE), and tetrachloroethene (PCE) were as high as 94 % and with effluent concentrations below 5 μM. In situ batch tests showed that the co-metabolic kinetics were faster with more chlorination. C2H6-oxidizing Comamonadaceae and "others," such as Methylococcaceae, oxidized C2H6 via monooxyenation reactions. The abundant non-ethane monooxygenases, particularly propane monooxygenase, appears to have been responsible for C2H6 aerobic metabolism and co-metabolism of chlorinated ethenes. This work proves that the C2H6 + O2 MBfR is a platform for ex-situ bioremediation of chlorinated ethenes, and the generalized action of the monooxygenases may make it applicable for other chlorinated organic contaminants.}, } @article {pmid37741938, year = {2023}, author = {Katsipis, G and Avgoulas, DI and Geromichalos, GD and Petala, M and Pantazaki, AA}, title = {In vitro and in silico evaluation of the serrapeptase effect on biofilm and amyloids of Pseudomonas aeruginosa.}, journal = {Applied microbiology and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37741938}, issn = {1432-0614}, abstract = {Pseudomonas aeruginosa is an emerging threat for hospitalized and cystic fibrosis patients. Biofilm, a microbial community embedded in extracellular polymeric substance, fortifies bacteria against the immune system. In biofilms, the expression of functional amyloids is linked with highly aggregative, multi-resistant strains, and chronic infections. Serrapeptase (SPT), a protease possessing similar or superior anti-microbial properties with many antibiotics, presents anti-amyloid potential. However, studies on the employment of SPT against Pseudomonas biofilms and Fap amyloid, or the possible mechanisms of action are scarce. Here, SPT inhibited biofilm formation of P. aeruginosa ATCC 27853 on both plastic and glass surfaces, with an IC50 of 11.26 µg/mL and 0.27 µg/mL, respectively. The inhibitory effect of SPT on biofilm was also verified with optical microscopy of crystal violet-stained biofilms and with confocal microscopy. Additionally, SPT caused a dose-dependent decrease of bacterial viability (IC50 of 3.07 µg/mL) as demonstrated by MTT assay. Reduction of bacterial functional amyloids was also demonstrated, employing both fluorescence microscopy with thioflavin T and photometrical determination of Congo-red-positive compounds. Both viability and functional amyloids correlated significantly with biofilm inhibition. Finally, in silico molecular docking studies provided a mechanistic insight into the interaction of SPT with FapC or FapD, proving that both peptides are possible targets of SPT. These results offer new insights into the biofilm formation of P. aeruginosa and potentiate the involvement of SPT in the prevention and eradication of Pseudomonas biofilms. KEY POINTS: • Serrapeptase inhibits biofilm formation of P. aeruginosa on plastic and glass. • Biofilm inhibition correlated with reduced viability and functional amyloid levels. • In silico studies indicated that serrapeptase may target FapC and FapD peptides.}, } @article {pmid37741585, year = {2023}, author = {Liu, JY and Jia, JJ and Liu, M and Duan, H and Hu, ML and Liu, C and Xue, RY and Jin, ZL and Zhang, SS and Li, GC and Feng, R and Jin, Z and Li, HB and He, L}, title = {A novel indolylbenzoquinone compound HL-J6 suppresses biofilm formation and α-toxin secretion in methicillin-resistant Staphylococcus aureus.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106972}, doi = {10.1016/j.ijantimicag.2023.106972}, pmid = {37741585}, issn = {1872-7913}, abstract = {Eradication of methicillin-resistant Staphylococcus aureus (MRSA) is challenging due to multi-drug resistance of the strains and the biofilm formation, the latter being important barriers to the penetration of antibiotics and host defenses. Thus, there is an urgent need to discover and develop novel agents to fight against MRSA-associated infection. In this study, HL-J6, a novel indolylbenzoquinone compound, performed inhibition against Staphylococcus aureus strains, with MIC (minimal inhibitory concentration) against MRSA252 of 2 μg/mL. Moreover, HL-J6 exhibited potent antibiofilm activity in vitro and were able to kill bacteria in the biofilm. In the mouse models of wound infection, HL-J6 treatment significantly reduced the MRSA load and inhibited biofilm formation on the wounds. The potent targets of its antibiofilm activity were explored by real-time RT-PCR, which indicated that HL-J6 downregulated the transcription level of sarA, atlAE and icaADBC. Moreover, western blot results showed that HL-J6 reduced the secretion level of α-toxin, a major virulence factor. Those findings indicated that HL-J6 is a promising lead compound for the development of novel drugs against MRSA biofilm infections.}, } @article {pmid37741388, year = {2023}, author = {Zhou, T and Xiang, Y and Liu, S and Ma, H and Shao, Z and He, Q and Chai, H}, title = {Microbial community dynamics and metagenomics reveal the potential role of unconventional functional microorganisms in nitrogen and phosphorus removal biofilm system.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167194}, doi = {10.1016/j.scitotenv.2023.167194}, pmid = {37741388}, issn = {1879-1026}, abstract = {The conventional functional microorganisms for nitrogen and phosphorus removal, such as Nitrosomonas, Nitrobacter, Nitrospira and Candidatus Accumulibacter, were hotspots in past research. However, the role of diverse unconventional functional microorganisms was neglected. In this study, a biofilm system was developed to explore the potential role of unconventional functional microorganisms in nutrients removal. According to the results of microbial community dynamics and metagenomics, complete ammonia oxidizing (comammox) bacteria was 20 times more abundant than ammonia-oxidizing bacteria (AOB) at day 121 and its abundance of amoA gene was almost the same as AOB. Although Nitrospira dominated the nitrite-oxidizing bacteria (NOB), diverse unconventional nxrB-containing microorganisms, particularly Chloroflexi, also significantly contributed to the nitrite oxidation. Binning analysis showed that Myxococcota-affiliated Haliangium had the necessary genes owns by phosphorus-accumulating organisms (PAO) and was likely to be the primary PAO since its abundance (6.38 %) was much higher than other conventional PAO (0.70 %). Comparing metagenome-assembled genomes of comammox bacteria with AOB and ammonia-oxidizing archaea (AOA), it possessed potential metabolic versatility in hydrogen and phosphorus, which may be the primary reason for the positive effect of the alternating anaerobic and aerobic conditions on the enrichment of comammox bacteria. Collectively, our findings broaden the understanding on the microbial mechanism of nitrogen and phosphorus removal in biofilm system.}, } @article {pmid37741376, year = {2023}, author = {Cao, G and Gao, J and Song, J and Jia, X and Liu, Y and Niu, J and Yuan, X and Zhao, Y}, title = {Performance and mechanism of chromium reduction in denitrification biofilm system with different carbon sources.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167191}, doi = {10.1016/j.scitotenv.2023.167191}, pmid = {37741376}, issn = {1879-1026}, abstract = {In the process of biological reduction of Cr(VI), the type of carbon sources affects the rate and effect of Cr(VI) reduction, but its specific performance and influencing mechanism have not yet been explored. In this study, four denitrification biofilm reactors were operated under four common carbon sources (C6H12O6, CH3COONa, CH3OH, CH3COONa:C6H12O6 1:1) to reveal the impact of carbon sources on Cr(VI) reduction. Through preliminary experimental concentration research, 75 mg/L Cr(VI) was selected as the dosing concentration. In long-term operation, the composite carbon sources of CH3COONa and C6H12O6 demonstrated excellent stability and achieved an impressive Cr(VI) removal efficiency of 99.5 %. The following sequence was C6H12O6, CH3COONa, and CH3OH. Among them, CH3OH was less competitive and the system was severely unbalanced with lowest Cr(VI) reduction efficiency. The toxicity reactions, changes in EPS and its functional groups, and electron transfer revealed the reduction and fixation mechanism of chromium on denitrification biofilm. The changes in microbial communities indicated that microbial communities in composite carbon sources can quickly adapt to the high toxic environment. The proportion of Trichococcus reached 43.6 %, which played an important role in denitrification and Cr(VI) reduction. Meanwhile, the prediction of microbial COG function reflected its excellent metabolic ability and defense mechanism.}, } @article {pmid37740256, year = {2023}, author = {Jacquiod, S and Olsen, NMC and Blouin, M and Røder, HL and Burmølle, M}, title = {Genotypic variations and interspecific interactions modify gene expression and biofilm formation of Xanthomonas retroflexus.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16503}, pmid = {37740256}, issn = {1462-2920}, support = {27620//Novo Nordisk Fonden/ ; RA19028.AEC.IS//I-SITE Junior Fellowship BFC/ ; 10098/35906/34434//Villum Fonden/ ; }, abstract = {Multispecies biofilms are important models for studying the evolution of microbial interactions. Co-cultivation of Xanthomonas retroflexus (XR) and Paenibacillus amylolyticus (PA) systemically leads to the appearance of an XR wrinkled mutant (XRW), increasing biofilm production. The nature of this new interaction and the role of each partner remain unclear. We tested the involvement of secreted molecular cues in this interaction by exposing XR and XRW to PA or its supernatant and analysing the response using RNA-seq, colony-forming unit (CFU) estimates, biofilm quantification, and microscopy. Compared to wild type, the mutations in XRW altered its gene expression and increased its CFU number. These changes matched the reported effects for one of the mutated genes: a response regulator part of a two-component system involved in environmental sensing. When XRW was co-cultured with PA or its supernatant, the mutations effects on XRW gene expression were masked, except for genes involved in sedentary lifestyle, being consistent with the higher biofilm production. It appears that the higher biofilm production was the result of the interaction between the genetic context (mutations) and the biotic environment (PA signals). Regulatory genes involved in environmental sensing need to be considered to shed further light on microbial interactions.}, } @article {pmid37739955, year = {2023}, author = {Cámara-Almirón, J and Domínguez-García, L and El Mammeri, N and Lends, A and Habenstein, B and de Vicente, A and Loquet, A and Romero, D}, title = {Molecular characterization of the N-terminal half of TasA during amyloid-like assembly and its contribution to Bacillus subtilis biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {68}, pmid = {37739955}, issn = {2055-5008}, support = {BacBio 637971//EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)/ ; UMA18-FEDERJA-055//Junta de Andalucía/ ; P20_00479//Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (Ministry of Economy, Innovation, Science and Employment, Government of Andalucia)/ ; PID2019-107724GB-I00//Ministry of Economy and Competitiveness | Agencia Estatal de Investigación (Spanish Agencia Estatal de Investigación)/ ; }, abstract = {Biofilms are bacterial communities that result from a cell differentiation process leading to the secretion of an extracellular matrix (ECM) by part of the population. In Bacillus subtilis, the main protein component of the ECM is TasA, which forms a fiber-based scaffold that confers structure to the ECM. The N-terminal half of TasA is strongly conserved among Bacillus species and contains a protein domain, the rigid core (RcTasA), which is critical for the structural and functional properties of the recombinant protein. In this study, we demonstrate that recombinantly purified RcTasA in vitro retains biochemical properties previously observed for the entire protein. Further analysis of the RcTasA amino acid sequence revealed two aggregation-prone stretches and a region of imperfect amino acid repeats, which are known to contribute to functional amyloid assembly. Biochemical characterization of these stretches found in RcTasA revealed their amyloid-like capacity in vitro, contributing to the amyloid nature of RcTasA. Moreover, the study of the imperfect amino acid repeats revealed the critical role of residues D64, K68 and D69 in the structural function of TasA. Experiments with versions of TasA carrying the substitutions D64A and K68AD69A demonstrated a partial loss of function of the protein either in the assembly of the ECM or in the stability of the core and amyloid-like properties. Taken together, our findings allow us to better understand the polymerization process of TasA during biofilm formation and provide knowledge into the sequence determinants that promote the molecular behavior of protein filaments in bacteria.}, } @article {pmid37737633, year = {2023}, author = {Glazier, VE and Kramara, J and Ollinger, T and Solis, NV and Zarnowski, R and Wakade, RS and Kim, MJ and Weigel, GJ and Liang, SH and Bennett, RJ and Wellington, M and Andes, DR and Stamnes, MA and Filler, SG and Krysan, DJ}, title = {The Candida albicans reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates filamentation, biofilm formation, and oral commensalism.}, journal = {mBio}, volume = {}, number = {}, pages = {e0152123}, doi = {10.1128/mbio.01521-23}, pmid = {37737633}, issn = {2150-7511}, abstract = {Candida albicans is a diploid human fungal pathogen that displays significant genomic and phenotypic heterogeneity over a range of virulence traits and in the context of a variety of environmental niches. Here, we show that the effect of Rob1 on biofilm and filamentation virulence traits is dependent on both the specific environmental condition and the clinical strain of C. albicans. The C. albicans reference strain SC5314 is a ROB1 heterozygote with two alleles that differ by a single nucleotide polymorphism at position 946, resulting in a serine- or proline-containing isoform. An analysis of 224 sequenced C. albicans genomes indicates that SC5314 is the only ROB1 heterozygote documented to date and that the dominant allele contains a proline at position 946. Remarkably, the ROB1 alleles are functionally distinct, and the rare ROB1[946S] allele supports increased filamentation in vitro and increased biofilm formation in vitro and in vivo, suggesting it is a phenotypic gain-of-function allele. SC5314 is among the most highly filamentous and invasive strains characterized to date. Introduction of the ROB1[946S] allele into a poorly filamenting clinical isolate increases filamentation, and conversion of an SC5314 laboratory strain to a ROB1[946S] homozygote increases in vitro filamentation and biofilm formation. In a mouse model of oropharyngeal infection, the predominant ROB1[946P] allele establishes a commensal state while the ROB1[946S] phenocopies the parent strain and invades into the mucosae. These observations provide an explanation for the distinct phenotypes of SC5314 and highlight the role of heterozygosity as a driver of C. albicans phenotypic heterogeneity. IMPORTANCE Candida albicans is a commensal fungus that colonizes the human oral cavity and gastrointestinal tract but also causes mucosal as well as invasive disease. The expression of virulence traits in C. albicans clinical isolates is heterogeneous and the genetic basis of this heterogeneity is of high interest. The C. albicans reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates. Here, we show that SC5314 derivatives are heterozygous for the transcription factor Rob1 and contain an allele with a rare gain-of-function SNP that drives filamentation, biofilm formation, and virulence in a model of oropharyngeal candidiasis. These findings explain, in part, the outlier phenotype of the reference strain and highlight the role heterozygosity plays in the strain-to-strain variation of diploid fungal pathogens.}, } @article {pmid37734627, year = {2023}, author = {Song, Y and Wang, R and Pan, Y and Fang, D and Tian, Y and Zhou, S}, title = {An Integrated Quorum Quenching Biocatalytic Nanoplatform for Synergistic Chemo-Photothermal Eradication of P. aeruginosa Biofilm Infections.}, journal = {Acta biomaterialia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.actbio.2023.09.021}, pmid = {37734627}, issn = {1878-7568}, abstract = {Decontamination of biofilm-associated infections presents a significant challenge due to the physical and chemical barrier created by the formation of extracellular matrices. This barrier restricts the access of antibiotics to the bacterial communities within the biofilm and provides protection to the persister cells, potentially leading to antibiotic resistance. In this study, we have developed an integrated quorum quenching biocatalytic nanoplatform for the synergistic chemo-photothermal eradication of P. aeruginosa biofilm infections. Ciprofloxacin (Cip), a model antibiotic, was absorbed onto PDA NPs through π-π stacking. Additionally, acylase (AC) was immobilized on PDA NPs through Schiff base reaction and Michael addition, resulting in the formation of the biocatalytic nanoplatform (PDA-Cip-AC NPs). This biocatalytic nanoplatform was able to enzymatically degrade AHL signaling molecules, thus achieving efficient quorum quenching activity to prevent biofilm formation. Furthermore, the NIR light-triggered on-demand Ciprofloxacin release further enhanced the eradication of P. aeruginosa biofilm infections with a synergy of local hyperthermia. We envision that this integrated quorum quenching nanoplatform provides a reliable tool for combating P. aeruginosa biofilm infections. STATEMENT OF SIGNIFICANCE: : An integrated quorum quenching biocatalytic nanoplatform has been developed for the eradication of P. aeruginosa biofilm infections. Quorum-sensing signals play a crucial role in modulating bacterial cell-to-cell communication, biofilm formation, and secretion of virulence factors. This biocatalytic nanoplatform efficiently degrades AHL signaling molecules, thereby blocking cell-to-cell communication and preventing biofilm formation. Additionally, local hyperthermia and on-demand Ciprofloxacin release were achieved through NIR irradiation, working synergistically to eradicate P. aeruginosa biofilm infections.}, } @article {pmid37734593, year = {2023}, author = {Sunnerhagen, T and Schwartz, F and Christophersen, L and Bjarnsholt, T and Qvortrup, K and Eldrup, N and Vogt, K and Moser, C}, title = {Biofilm formation on endovascular aneurysm repair (EVAR) grafts- a proof of concept in vitro model.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cmi.2023.09.012}, pmid = {37734593}, issn = {1469-0691}, abstract = {OBJECTIVES: An endovascular aneurysm repair (EVAR) graft is a catheter-implanted vascular prosthesis and is the preferred treatment for patients with aortic aneurysm. If an EVAR graft becomes the focus of infection, the treatment possibilities are limited as it is technically difficult to remove the graft to obtain source control. This study examines whether Pseudomonas aeruginosa and Staphylococcus aureus form biofilm on EVAR prostheses.

METHODS: EVAR graft sections were exposed to bacteria at 10[2] or 10[8] colony forming units (CFU)/ml in lysogeny broth and Krebs-Ringer at 37°C, bacterial biofilm formation was evaluated by scanning electron microscopy (SEM) and counting CFU on the graft sections following antibiotic exposure at x10 minimal inhibitory concentration (MIC). Bacteria were tested for tolerance to benzyl penicillin, tobramycin and ciprofloxacin.

RESULTS: Bacterial exposure for 15 minutes established biofilms on all prosthesis fragments (6/6 replicates). After 4 hours, bacteria were firmly attached to the EVAR prostheses and resisted washing. After 18 to 24 hours the median CFU/g of EVAR graft reached 5.2 x 10[8] (1.15 x 10[8] - 1.1 x 10[9]) for S. aureus and 9.1 x 10[7] (3.5 x 10[7] - 6.25 x 10[8]) for P. aeruginosa. SEM showed bacterial attachment to the graft pieces. There was a time-dependent development of tolerance with approximately 20 (tobramycin), 560 (benzyl penicillin), and 600 (ciprofloxacin) times more S. aureus surviving antibiotic exposure in 24 compared to 0 hours old biofilm. Five (tobramycin) and 170 times (ciprofloxacin) more P. aeruginosa survived antibiotic exposure in 24 compared to 0 hours old biofilms.

CONCLUSIONS: Our results show that bacteria can rapidly adhere to and subsequently form antibiotic tolerant biofilms on EVAR graft material in concentrations equivalent to levels seen in transient bacteremia in vivo. Potentially, the system can be used for identifying optimal treatment combinations for infected EVAR prosthesis.}, } @article {pmid37734201, year = {2023}, author = {Liu, X and Qi, X and Gu, Y and Huang, X and Liang, P}, title = {Titanium mesh as the anode of electrochemically active biofilm sensor for improved sensitivity in water toxicity real-time early-warning.}, journal = {Biosensors & bioelectronics}, volume = {241}, number = {}, pages = {115692}, doi = {10.1016/j.bios.2023.115692}, pmid = {37734201}, issn = {1873-4235}, abstract = {As serious water ecological pollution caused by toxicant leakage occurs frequently, early-warning for toxicity presented in water environment attracts increasing attentions as it saves time to retain water safety and human health. Electrochemically active biofilm (EAB) sensor is a promising device for in situ real-time water toxicity early-warning. To improve the sensitivity of EAB sensor particularly for low-concentration toxicity warning, this study employed titanium mesh (TiM) as the anode to construct an EAB sensor. Compared to traditional EAB sensor with carbon felt (CF) anode, the sensitivity of the TiM sensor was increased up to 37.4 times. The effects of mesh size (TiM50, TiM100, TiM150) and operation mode (flow-by and flow-through) on the sensitivity of TiM sensors were further investigated. Results showed the sensor with TiM100 anode had the highest inhibition rate (IR) in flow-by mode, attributed to low charge transfer resistance (Rct) and fast mass transfer. Flow-through operation could further enhance TiM100 sensor's sensitivity from flow-by operation and succeeded to signal as low as 0.0025% formaldehyde, the lowest so far tested in EAB sensor with sensing anode. Multiple toxicity shocks on flow-through TiM100 sensor revealed its good recoverability towards all tested formaldehyde concentration from 0.01% to 0.0025%, during which electrochemical activity degradation and biomass accumulation partially impaired the repeatability. This work highlights the great improvement of EAB sensors by utilizing titanium mesh as EAB carrier and provides a reference for the practical application of metallic materials for EAB sensors.}, } @article {pmid37733635, year = {2023}, author = {Luo, T and Dai, X and Wei, W and Xu, Q and Ni, BJ}, title = {Microplastics Enhance the Prevalence of Antibiotic Resistance Genes in Anaerobic Sludge Digestion by Enriching Antibiotic-Resistant Bacteria in Surface Biofilm and Facilitating the Vertical and Horizontal Gene Transfer.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c02815}, pmid = {37733635}, issn = {1520-5851}, abstract = {Antibiotic resistance genes (ARGs) and microplastics (MPs) are recognized as emerging contaminants and threats to global human health. Despite both of them being significantly detected in their "hotspots", i.e., waste activated sludge (WAS), rare studies on how MPs affect ARGs and antibiotic-resistant bacteria (ARB) in anaerobic sludge digestion are available. Herein, the fate of ARGs and ARB after exposure to MPs of three dosages (10, 30, and 80 particles/g-TS), three polymer types (LDPE, PET, and PS), and three branching extents (LDPE, LLDPE, and HDPE) in anaerobic sludge digestion was investigated. Metagenomic results indicated that all variants of MPs resulted in an increase of the relative abundance of ARGs in the digester compared to the control. The abundance of ARGs demonstrated a dosage-dependent relationship within the range from 10 to 80 particles/g-TS, resulting in an increase from 4.5 to 27.9% compared to the control. Branching structure and polymer type influence ARG level in the sludge digester as well. Mechanism studies revealed that LDPE selectively enriched potential ARB and ARGs in the surface biofilm, possibly creating a favorable environment for ARB proliferation and ARG exchange. Furthermore, vertical transfer of ARGs was facilitated by LDPE through increasing bacterial cell proliferation accompanied by the enhancement of relevant functional genes. The elevated abundance of mobile genetic elements (MGEs) and ARGs-carrying plasmids also demonstrated that MGE-mediated horizontal transfer was promoted by LDPE at 80 particles/g-TS. This effect was compounded by increased oxidative stress, cell membrane permeability, and cell cohesion, collectively facilitating horizontal ARG transfer. Consequently, both vertical and horizontal transfer of ARGs could be concurrently promoted by LDPE an in anaerobic sludge digester.}, } @article {pmid37733193, year = {2023}, author = {Sharma, S and Saraf, M}, title = {Biofilm-forming plant growth-promoting rhizobacterial consortia isolated from mines and dumpsites assist green remediation of toxic metal (Ni and Pb) using Brassica juncea.}, journal = {Biologia futura}, volume = {}, number = {}, pages = {}, pmid = {37733193}, issn = {2676-8607}, abstract = {To study how biofilm-forming rhizobacteria isolated from mines and dumpsites improved the phytoremediation efficacy of B. juncea in metal-contaminated soil. Out of 91 isolates, six were chosen for research based on their tolerance to metals, and their efficient PGPR properties, and subjected to the design of a consortium. A compatibility study revealed no antagonistic interaction between rhizobacterial-consortiums. The results of the biofilm formation and FEG-SEM studies revealed that a consortium-BC8 formed a strong biofilm on the root surface of B. juncea seedlings. Based on results obtained with the phytoextraction efficiency of B. juncea in consortium-BC8 (SMHMZ46 and SMHMP23), they were identified as Klebsiella variicola and Pseudomonas otitidis, respectively, and submitted to NCBI GenBank with accession numbers MZ145092 and OK560623. This rhizobacteria is the first to be reported as assisting Ni and Pb phytoremediation by employing B. juncea. Soil inoculation with consortium-BC8 increased the amount of soluble Ni and Pb by 13.25-fold and 10.69-fold, respectively, when compared to the control. These consortiums-BC8 significantly increased vegetative growth and metal accumulation in root and shoot with a translocation-factor of 1.58 for Ni and soil to root with a bioconcentration-factor of 1.3 for Pb in B. juncea grown in individual soil contamination with 96.05 mg/kg NiCl2 and 89.63 mg/kg Pb(NO3)2, which are significantly higher than other consortium treatments and the non-inoculated control. B. juncea amendments with a biofilm-forming consortium-BC8 having TF, BCF, and BAC > 1 for Ni, whereas BCF > 1, TF, and BAC < 1 for Pb, are appropriate for green remediation of Ni and phytostabilization of Pb.}, } @article {pmid37733140, year = {2023}, author = {Olaniran, OB and Donia, A and Adeleke, OE and Bokhari, H}, title = {Prevalence of Type III Secretion System (T3SS) and Biofilm Development in Genetically Heterogeneous Clinical Isolates of Pseudomonas aeruginosa from Nigeria.}, journal = {Current microbiology}, volume = {80}, number = {11}, pages = {349}, pmid = {37733140}, issn = {1432-0991}, abstract = {Pseudomonas aeruginosa infection in seriously ill patients is a major concern due to its ability to form biofilm and secrete effector toxins. There is little information on the prevalence of T3SS effector toxins and biofilm production in clinical isolates of P. aeruginosa from Nigeria. The goal of this study is to evaluate the prevalence of T3SS toxins and biofilm production among isolates from selected tertiary hospitals in Nigeria. This study examined 430 clinical isolates from our previous work, comprising 181 MDR (multidrug-resistant) and 249 non-MDR isolates. Biofilm production and type III secretion toxins were determined using colorimetric microtiter plate assay and polymerase chain reaction, respectively. Carbapenem-resistant isolates were typed using REP-PCR and BOX-PCR. Biofilm production was detected in 386/430 (89.8%) of the isolates. Out of 386 biofilm producers, 167 (43.3%) were multidrug-resistant isolates. PCR identified four T3SS virulence types among 430 isolates, including 78 (18.1%) exoU+/exoS- isolates, 343 (79.8%) exoU-/exoS + isolates, 5 (1.2%) exoU+/exoS + isolates, and 4 (0.9%) exoU-/exoS- isolates. Both REP- and BOX-PCR consist of eight clusters. On the REP-PCR dendrogram, ExoU[+]/ExoS[-] isolates majorly occupied cluster IV. Clusters IV, VII, and VIII consist of isolates from wounds on BOX-PCR dendrogram. There was a positive association between strong biofilm production and multidrug resistance in our P. aeruginosa isolates. This study identified multidrug-resistant, biofilm-producing P. aeruginosa strains that secrete cytotoxic effectors which are significant virulence factors in P. aeruginosa. This poses a severe risk to our healthcare system and highlights the importance of continuous surveillance to prevent infectious disease outbreaks.}, } @article {pmid37732783, year = {2023}, author = {Fan, Z and Fu, T and Li, Z and Du, B and Cui, X and Zhang, R and Feng, Y and Zhao, H and Xue, G and Cui, J and Yan, C and Gan, L and Feng, J and Xu, Z and Yu, Z and Tian, Z and Ding, Z and Chen, J and Chen, Y and Yuan, J}, title = {The role of integration host factor in biofilm and virulence of high-alcohol-producing Klebsiella pneumoniae.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0117023}, doi = {10.1128/spectrum.01170-23}, pmid = {37732783}, issn = {2165-0497}, abstract = {Klebsiella pneumoniae is a well-known human nosocomial pathogen with an arsenal of virulence factors, including capsular polysaccharides (CPS), fimbriae, flagella, and lipopolysaccharides (LPS). Our previous study found that alcohol acted as an essential virulence factor for high-alcohol-producing K. pneumoniae (HiAlc Kpn). Integration host factor (IHF) is a nucleoid-associated protein that functions as a global virulence regulator in Escherichia coli. However, the regulatory role of IHF in K. pneumoniae remains unknown. In the present study, we found that deletion of ihfA or ihfB resulted in a slight defect in bacterial growth, a severe absence of biofilm formation and cytotoxicity, and a significant reduction in alcohol production. RNA sequencing differential gene expression analysis showed that compared with the wild-type control, the expression of many virulence factor genes was downregulated in ΔihfA and ΔihfB strains, such as those related to CPS (rcsA, galF, wzi, and iscR), LPS (rfbABCD), type I and type III fimbriae (fim and mrk operon), cellulose (bcs operon), iron transporter (feoABC, fhuA, fhuF, tonB, exbB, and exbD), quorum sensing (lsr operon and sdiA), type II secretion system (T2SS) and type VI secretion system (T6SS) (tssG, hcp, and gspE). Of these virulence factors, CPS, LPS, fimbriae, and cellulose are involved in biofilm formation. In addition, IHF could affect the alcohol production by regulating genes related to glucose intake (ptsG), pyruvate formate-lyase, alcohol dehydrogenase, and the tricarboxylic acid (TCA) cycle. Our data provided new insights into the importance of IHF in regulating the virulence of HiAlc Kpn. IMPORTANCE Klebsiella pneumoniae is a well-known human nosocomial pathogen that causes various infectious diseases, including urinary tract infections, hospital-acquired pneumonia, bacteremia, and liver abscesses. Our previous studies demonstrated that HiAlc Kpn mediated the development of nonalcoholic fatty liver disease by producing excess endogenous alcohol in vivo. However, the regulators regulating the expression of genes related to metabolism, biofilm formation, and virulence of HiAlc Kpn remain unclear. In this study, the regulator IHF was found to positively regulate biofilm formation and many virulence factors including CPS, LPS, type I and type III fimbriae, cellulose, iron transporter, AI-2 quorum sensing, T2SS, and T6SS in HiAlc Kpn. Furthermore, IHF positively regulated alcohol production in HiAlc Kpn. Our results suggested that IHF could be a potential drug target for treating various infectious diseases caused by K. pneumoniae. Hence, the regulation of different virulence factors by IHF in K. pneumoniae requires further investigation.}, } @article {pmid37732743, year = {2023}, author = {Diarra, C and Goetz, C and Gagnon, M and Roy, D and Jean, J}, title = {Biofilm formation by heat-resistant dairy bacteria: multispecies biofilm model under static and dynamic conditions.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0071323}, doi = {10.1128/aem.00713-23}, pmid = {37732743}, issn = {1098-5336}, abstract = {In the food industry, especially dairy, biofilms can be formed by heat-resistant spoilage and pathogenic bacteria from the farm. Such biofilms may persist throughout the processing chain and contaminate milk and dairy products continuously, increasing equipment cleaning, maintenance costs, and product recalls. Most biofilms are multispecies, yet most studies focus on single-species models. A multispecies model of dairy biofilm was developed under static and dynamic conditions using heat-resistant Bacillus licheniformis, Pseudomonas aeruginosa, Clostridium tyrobutyricum, Enterococcus faecalis, Streptococcus thermophilus, and Rothia kristinae isolated from dairies. C. tyrobutiricum and R. kristinae were weak producers of biofilm, whereas the other four were moderate to strong producers. Based on cross-streaking on agar, P. aeruginosa was found to inhibit B. licheniformis and E. faecalis. In multispecies biofilm formed on stainless steel in a CDC reactor fed microfiltered milk, the strong biofilm producers were dominant while the weak producers were barely detectable. All biofilm matrices were dispersed easily by proteinase K treatment but were less sensitive to DNase or carbohydrases. Further studies are needed to deepen our understanding of multispecies biofilms and interactions within to develop improved preventive strategies to control the proliferation of spoilage and pathogenic bacteria in dairies and other food processing environments. IMPORTANCE A model of multispecies biofilm was created to study biofilm formation by heat-resistant bacteria in the dairy industry. The biofilm formation potential was evaluated under static conditions. A continuous flow version was then developed to study multispecies biofilm formed on stainless steel in microfiltered milk under dynamic conditions encountered in dairy processing equipment. The study of biofilm composition and bacterial interactions therein will lead to more effective means of suppressing bacterial growth on food processing equipment and contamination of products with spoilage and pathogenic bacteria, which represent considerable economic loss.}, } @article {pmid37732737, year = {2023}, author = {Rudin, L and Roth, N and Kneubühler, J and Dubey, BN and Bornstein, MM and Shyp, V}, title = {Inhibitory effect of natural flavone luteolin on Streptococcus mutans biofilm formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0522322}, doi = {10.1128/spectrum.05223-22}, pmid = {37732737}, issn = {2165-0497}, abstract = {Streptococcus mutans is one of the key pathogens responsible for dental caries, which is known to be one of the most prevalent biofilm-associated diseases worldwide. S. mutans virulence strongly depends on its biofilm formation and enamel demineralization abilities due to the production of surface adhesins, exopolysaccharides, and acid in the presence of sugar. Luteolin is an abundant natural flavone with a prominent anti-bacterial function. However, it remains unclear how luteolin affects S. mutans pathogenicity including its acidogenicity and biofilm formation. In this study, the effect of luteolin on S. mutans growth, acid production, and its early and late biofilm formation and biofilm disruption was tested. Luteolin shows strong anti-biofilm activity, while it remains non-toxic for bacterial cell viability. In the biofilm, luteolin reduces the expression of S. mutans virulence genes such as gbpC, spaP, gtfBCD, and ftf encoding for surface adhesins and extracellular polysaccharides (EPS)-producing enzymes, which reflects in the strong reduction of bacteria and EPS. Further, it reduces water-insoluble glucan production in the biofilm, potentially, via direct interference with glucosyltransfereases (Gtfs). Moreover, at biofilm inhibitory concentrations, luteolin significantly reduces acid production by S. mutans. Finally, luteolin could target S. mutans amyloid proteins to disrupt the biofilm based on the observation that it inhibits the uptake of the amyloid dye, thioflavin T, by S. mutans extracellular proteins and failed to inhibit biofilm formation by the mutant strain lacking three main amyloid proteins. In conclusion, luteolin appears to be a potent natural compound with pleiotropic anti-biofilm properties against one of the main cariogenic human pathogens, S. mutans. IMPORTANCE Flavonoids are natural compounds with proven anti-bacterial and anti-biofilm properties. Here, we describe the anti-biofilm properties of natural flavone luteolin against the main cariogenic bacteria, S. mutans. Luteolin inhibited gene expression of cell surface adhesins, fructosyltransferases, and glucosyltransferases, which promotes a significant reduction of bacterial and EPS biomass in early and late biofilms. Moreover, luteolin could directly target S. mutans Gtfs and functional amyloids to modulate pathogenic biofilms. These observations provide important insights into the anti-biofilm properties of luteolin while laying out a framework for future therapeutic strategies targeting biofilm-associated virulence factors of oral pathogens.}, } @article {pmid37732719, year = {2023}, author = {Kher, L and Santoro, D}, title = {Biofilm Models: Different Ways of Biofilm Characterization and Drug Discovery.}, journal = {Current protocols}, volume = {3}, number = {9}, pages = {e894}, doi = {10.1002/cpz1.894}, pmid = {37732719}, issn = {2691-1299}, abstract = {The ability of bacteria to develop biofilms and its added effect on antimicrobial resistance have been a concern for both animal and human medicine. The need to understand biofilm biology has been addressed with the help of three biofilm models, i.e., in vitro, ex vivo, and in vivo. Due to the implications of animal welfare involved in in vivo models, this article is mainly focused on in vitro and ex vivo study models to analyze biofilm biology. In in vitro biofilm models, the microtiter plate and Calgary biofilm device are the most commonly used techniques for biofilm analysis. Quantification of the biofilm biomass generated by these two techniques can be assessed with the help of a crystal violet assay. Although in vitro biofilm models help advance understanding of the biology of biofilm and are easy to perform, they fail to address certain important questions, such as the importance of the substrate on which biofilm grows and the interaction between the organisms and the substrate. To address this concern, an ex vivo model can be utilized to characterize the behavior and characteristics of biofilms on different substrates. Ex vivo biofilm models are considered a bridge between the in vitro and in vivo biofilm models. Although neither of the currently available biofilm assessment models is considered the gold standard, they have significantly increased understanding of biofilm behavior. Further studies are warranted to develop more refined biofilm models. © 2023 Wiley Periodicals LLC. Basic Protocol 1: In vitro biofilm models for microtiter plate/crystal violet assay for biofilm growth assessment Basic Protocol 2: Crystal violet assay/tissue culture plate method for testing of antibiofilm agents Alternate Protocol: Calgary biofilm device to determine biofilm susceptibility to antimicrobial agents Basic Protocol 3: Ex vivo biofilm skin models: canine/porcine skin explants.}, } @article {pmid37731931, year = {2023}, author = {Nesse, LL and Osland, AM and Asal, B and Mo, SS}, title = {Evolution of antimicrobial resistance in E. coli biofilm treated with high doses of ciprofloxacin.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1246895}, pmid = {37731931}, issn = {1664-302X}, abstract = {The evolution of antimicrobial resistance (AMR) has mainly been studied in planktonic bacteria exposed to sub-inhibitory antimicrobial (AM) concentrations. However, in a number of infections that are treated with AMs the bacteria are located in biofilms where they tolerate high doses of AM. In the present study, we continuously exposed biofilm residing E. coli at body temperature to high ciprofloxacin (CIP) concentrations increasing from 4 to 130 times the minimal inhibitory concentration (MIC), i.e., from 0.06 to 2.0 mg/L. After 1 week, the biofilms were full of CIP resistant bacteria. The evolutionary trajectory observed was the same as described in the literature for planktonic bacteria, i.e., starting with a single mutation in the target gene gyrA followed by mutations in parC, gyrB, and parE, as well as in genes for regulation of multidrug efflux pump systems and outer membrane porins. Strains with higher numbers of these mutations also displayed higher MIC values. Furthermore, the evolution of CIP resistance was more rapid, and resulted in strains with higher MIC values, when the bacteria were biofilm residing than when they were in a planktonic suspension. These results may indicate that extensive clinical AM treatment of biofilm-residing bacteria may not only fail to eradicate the infection but also pose an increased risk of AMR development.}, } @article {pmid37731930, year = {2023}, author = {Buchmann, D and Schwabe, M and Weiss, R and Kuss, AW and Schaufler, K and Schlüter, R and Rödiger, S and Guenther, S and Schultze, N}, title = {Natural phenolic compounds as biofilm inhibitors of multidrug-resistant Escherichia coli - the role of similar biological processes despite structural diversity.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1232039}, pmid = {37731930}, issn = {1664-302X}, abstract = {Multidrug-resistant gram-negative pathogens such as Escherichia coli have become increasingly difficult to treat and therefore alternative treatment options are needed. Targeting virulence factors like biofilm formation could be one such option. Inhibition of biofilm-related structures like curli and cellulose formation in E. coli has been shown for different phenolic natural compounds like epigallocatechin gallate. This study demonstrates this effect for other structurally unrelated phenolics, namely octyl gallate, scutellarein and wedelolactone. To verify whether these structurally different compounds influence identical pathways of biofilm formation in E. coli a broad comparative RNA-sequencing approach was chosen with additional RT-qPCR to gain initial insights into the pathways affected at the transcriptomic level. Bioinformatical analysis of the RNA-Seq data was performed using DESeq2, BioCyc and KEGG Mapper. The comparative bioinformatics analysis on the pathways revealed that, irrespective of their structure, all compounds mainly influenced similar biological processes. These pathways included bacterial motility, chemotaxis, biofilm formation as well as metabolic processes like arginine biosynthesis and tricarboxylic acid cycle. Overall, this work provides the first insights into the potential mechanisms of action of novel phenolic biofilm inhibitors and highlights the complex regulatory processes of biofilm formation in E. coli.}, } @article {pmid37731921, year = {2023}, author = {Haenelt, S and Richnow, HH and Müller, JA and Musat, N}, title = {Antibiotic resistance indicator genes in biofilm and planktonic microbial communities after wastewater discharge.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1252870}, pmid = {37731921}, issn = {1664-302X}, abstract = {The spread of bacteria with antibiotic resistance genes (ARGs) in aquatic ecosystems is of growing concern as this can pose a risk of transmission to humans and animals. While the impact of wastewater treatment plant (WWTP) effluent on ARG abundance in surface waters has been studied extensively, less is known about the fate of ARGs in biofilms. The proximity and dense growth of microorganisms in combination with the accumulation of higher antibiotic concentrations in biofilms might render biofilms a reservoir for ARGs. Seasonal parameters such as water temperature, precipitation, and antibiotic concentrations should be considered as well, as they may further influence the fate of ARGs in aquatic ecosystems. Here we investigated the effect of WWTP effluent on the abundance of the sulfonamide resistance genes sul1 and sul2, and the integrase gene intI1 in biofilm and surface water compartments of a river in Germany with a gradient of anthropogenic impact using quantitative PCR. Furthermore, we analyzed the bacterial community structure in both compartments via 16S rRNA gene amplicon sequencing, following the river downstream. Additionally, conventional water parameters and sulfonamide concentrations were measured, and seasonal aspects were considered by comparing the fate of ARGs and bacterial community diversity in the surface water compartment between the summer and winter season. Our results show that biofilm compartments near the WWTP had a higher relative abundance of ARGs (up to 4.7%) than surface waters (<2.8%). Sulfonamide resistance genes were more persistent further downstream (>10 km) of the WWTP in the hot and dry summer season than in winter. This finding is likely a consequence of the higher proportion of wastewater and thus wastewater-derived microorganisms in the river during summer periods. We observed distinct bacterial communities and ARG abundance between the biofilm and surface water compartment, but even greater variations when considering seasonal and spatiotemporal parameters. This underscores the need to consider seasonal aspects when studying the fate of ARGs in aquatic ecosystems.}, } @article {pmid37731193, year = {2023}, author = {Yu, C and Qiao, J and Ali, Q and Jiang, Q and Song, Y and Zhu, L and Gu, Q and Borriss, R and Dong, S and Gao, X and Wu, H}, title = {degQ associated with the degS/degU two-component system regulates biofilm formation, antimicrobial metabolite production, and biocontrol activity in Bacillus velezensis DMW1.}, journal = {Molecular plant pathology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mpp.13389}, pmid = {37731193}, issn = {1364-3703}, support = {2022YFE0198100//Korea-China Cooperation Research Project/ ; 31972325//National Natural Science Foundation of China/ ; 32172490//National Natural Science Foundation of China/ ; BK 20200078//Natural Science Foundation for Excellent Youth Scholars of Jiangsu Province, China/ ; BK 20201239//Natural Science Foundation of Jiangsu Province/ ; NAUSY-M18//Guidance Foundation of Sanya Institute of Nanjing Agricultural University/ ; }, abstract = {The gram-positive bacterium Bacillus velezensis strain DMW1 produces a high level of antimicrobial metabolites that can suppress the growth of phytopathogens. We investigated the mechanism used by degQ and the degS/degU two-component system to regulate the biocontrol characteristics of DMW1. When degQ and degU were deleted, the biofilm formation, cell motility, colonization activities, and antifungal abilities of ΔdegQ and ΔdegU were significantly reduced compared to wild-type DMW1. The expression levels of biofilm-related genes (epsA, epsB, epsC, and tasA) and swarming-related genes (swrA and swrB) were all down-regulated. We also evaluated the impact on secondary metabolites of these two genes. The degQ and degU genes reduced surfactin and macrolactin production and up-regulated the production of fengycin, iturin, bacillaene, and difficidin metabolites. The reverse transcription-quantitative PCR results were consistent with these observations. Electrophoretic mobility shift assay and microscale thermophoresis revealed that DegU can bind to the promoter regions of these six antimicrobial metabolite genes and regulate their synthesis. In conclusion, we provided systematic evidence to demonstrate that the degQ and degU genes are important regulators of multicellular behaviour and antimicrobial metabolic processes in B. velezensis DMW1 and suggested novel amenable strains to be used for the industrial production of antimicrobial metabolites.}, } @article {pmid37730405, year = {2023}, author = {Gonçalves, MLL and Sobral, APT and Gallo, JMAS and Gimenez, T and Ferri, EP and Ianello, S and Motta, PB and Motta, LJ and Horliana, ACRT and Santos, EM and Bussadori, SK}, title = {Antimicrobial photodynamic therapy with erythrosine and blue light on dental biofilm bacteria: study protocol for randomised clinical trial.}, journal = {BMJ open}, volume = {13}, number = {9}, pages = {e075084}, pmid = {37730405}, issn = {2044-6055}, abstract = {INTRODUCTION: The objective is to investigate the effect of antimicrobial photodynamic therapy (aPDT) mediated by erythrosine and a blue light-emitting diode (LED) in the reduction of bacteria in dental biofilm.

METHODS AND ANALYSIS: This clinical trial will be conducted with 30 patients who have biofilm, but without the presence of periodontal pockets, and who are being treated at the Dental Clinic of Universidade Metropolitana de Santos. A split-mouth model will be used (n=30), with group 1 control (conventional treatment) and group 2 (conventional treatment and aPDT). The bicarbonate jet will be used to remove dental biofilm in both groups. The treatment will be carried out in one session. aPDT will be performed before cleaning/prophylaxis, only in group 2. Participants will rinse with the photosensitiser erythrosine (diluted to 1 mM) for 1 min of pre-irradiation time, so that the drug can stain all the bacterial biofilm. Then, the D-2000 LED (DMC) will be applied, emitting at a wavelength of ʎ=470 nm, radiant power of 1000 mW, irradiance of 0.532 W/cm[2] and radiant exposure of 63.8 J/cm[2]. Irradiation will be performed until the biofilm of the cervical region is illuminated for 2 min/point (4 cm[2]). The microbiological examination will be performed from samples of supragingival biofilm collected from the gingival sulcus. Collection will be performed in each experimental site before irradiation, immediately after the irradiation procedure and after the prophylaxis. Colony-forming units will be counted and the data will be submitted for statistical analysis for comparison of pretreatment and post-treatment results and between groups (conventional X aPDT).

ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee of Universidade Metropolitana de Santos under process number 66984123.0.0000.5509. Results will be published in peer-reviewed journals and will be presented at conferences.

TRIAL REGISTRATION NUMBER: NCT05805761.}, } @article {pmid37729639, year = {2023}, author = {Chen, B and Dong, K and Xu, Y and Jiang, M and Zheng, J and Zeng, H and Zhang, X and Chen, Y and Li, H}, title = {Biodegradation of nitrate and p-bromophenol using hydrogen-based membrane biofilm reactors in parallel.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/09593330.2023.2259091}, pmid = {37729639}, issn = {1479-487X}, abstract = {ABSTRACTP-bromophenol (4-BP) is a toxic halogenated phenolic organic compound. The conventional treatment processes for 4-BP elimination are costly and inefficient, with complete mineralization remaining a challenge for water treatment. To overcome these limitations, we investigated the treatment of 4-BP in a membrane biofilm reactor (MBfR) using hydrogen as an electron donor. The pathway of 4-BP degradation within the H2-MBfR was investigated through long-term operational experiments by considering the effect of nitrate and 4-BP concentrations, hydrogen partial pressure, static experiments, and microbial community diversity, which was studied using 16S rRNA. The results showed that H2-MBfR could quickly remove approximately 100% of 4-BP (up to 20 mg/L), with minimal intermediate product accumulation and 10 mg/L of nitrate continuously reduced. The microbial community structure showed that the presence of H2 created an anaerobic environment, and Thauera was the dominant functional genus involved in the degradation of 4-BP. The genes encoding related enzymes were further enhanced. This study provides an economically viable and environmentally friendly bioremediation technique for water bodies that contain 4-BP and nitrates.}, } @article {pmid37728257, year = {2023}, author = {Ranson, TM and Barton, ME and McLean, RJC}, title = {Influence of Central Metabolism Disruption on Escherichia coli Biofilm Formation.}, journal = {Canadian journal of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1139/cjm-2023-0096}, pmid = {37728257}, issn = {1480-3275}, abstract = {Biofilms are widely recognized as a prominent mode of microbial growth and strategy of antimicrobial tolerance in many environments. Characteristics that are often overlooked in biofilm investigations include the examination of metabolic pathways as the assumption might be that interference with central pathways such as glycolysis would only reduce growth and thus not be meaningful. Using the Keio collection of Escherichia coli mutants, we investigated the influence of biofilm formation and planktonic growth in full strength and diluted Luria-Bertani (LB) broth using strains with a disruption of glycolysis (Δpgi), the Entner-Doudoroff pathway (Δedd), or the pentose phosphate pathway (Δgnd). Unexpectedly, in contrast to the E. coli Keio parent strain (BW25113), planktonic growth was enhanced in full strength and diluted LB broth in the metabolic mutants. Using a microtiter biofilm assay, the E. coli parent strain showed the highest crystal violet staining. However, when analyzed by culture assays, there was an increase in biofilm populations in the mutants in comparison to the parent strain. Fluorescence microscopy showed differences in colonization patterns in the strains. Given the availability of mutant collections in many model organisms, similar metabolic studies are warranted for biofilms, given their importance in nature.}, } @article {pmid37728140, year = {2023}, author = {Khan, MA and Shahid, M and Celik, I and Khan, HM and Shahzad, A and Husain, FM and Adil, M}, title = {Attenuation of quorum sensing regulated virulence functions and biofilm of pathogenic bacteria by medicinal plant Artemisia annua and its phytoconstituent 1, 8-cineole.}, journal = {Microscopy research and technique}, volume = {}, number = {}, pages = {}, doi = {10.1002/jemt.24418}, pmid = {37728140}, issn = {1097-0029}, support = {RSPD2023R729//King Saud University/ ; }, abstract = {The emergence of multidrug resistance (MDR) in bacterial pathogens is a serious public health concern. A significant therapeutic target for MDR infections is the quorum sensing-regulated bacterial pathogenicity. Determining the anti-quorum sensing abilities of certain medicinal plants against bacterial pathogens as well as the in-silico interactions of particular bioactive phytocompounds with QS and biofilm-associated proteins were the objectives of the present study. In this study, 6 medicinal plants were selected based on their ethnopharmacological usage, screened for Anti-QS activity and Artemisia annua leaf extract (AALE) demonstrated pigment inhibitory activity against Chromobacterium violaceum CV12472. Further, the methanol active fraction significantly inhibited the virulence factors (pyocyanin, pyoverdine, rhamnolipid and swarming motility) of Pseudomonas aeruginosa PAO1 and Serratia marcescens MTCC 97 at respective sub-MICs. The inhibition of biofilm was determined using a microtiter plate test and scanning electron microscopy. Biofilm formation was impaired by 70%, 72% and 74% in P. aeruginosa, C. violaceum and S. marcescens, respectively at 0.5xMIC of the extract. The phytochemical content of the extract was studied using GC-MS and 1, 8-cineole was identified as major bioactive compound. Furthermore, 1, 8-cineole was docked with quorum sensing (QS) proteins (LasI, LasR, CviR, and rhlR) and biofilm proteins (PilY1 and PilT). In silico docking and dynamics simulations studies suggested interactions with QS-receptors CviR', LasI, LasR, and biofilm proteins PilY1, PilT for anti-QS activity. Further, 1, 8-cineole demonstrated 66% and 51% reduction in violacein production and biofilm formation, respectively to validate the findings of computational analysis. Findings of the present investigation suggests that 1, 8-cineole plays a crucial role in the QS and biofilm inhibitory activity demonstrated by Artemisia annua extract. RESEARCH HIGHLIGHTS: Artemisia annua leaf extract (AALE) methanol fraction demonstrated broad-spectrum QS and biofilm inhibition Scanning electron microscopy (SEM) confirmed biofilm inhibition Molecular docking and simulation studies suggested positive interactions of 1,8-cineol with QS-receptors and biofilm proteins.}, } @article {pmid37726220, year = {2023}, author = {Aghili, SS and Jahangirnia, A and Alam, M and Oskouei, AB and Golkar, M and Badkoobeh, A and Abbasi, K and Mohammadikhah, M and Karami, S and Soufdoost, RS and Namanloo, RA and Talebi, S and Amookhteh, S and Hemmat, M and Sadeghi, S}, title = {The effect of photodynamic therapy in controlling the oral biofilm: A comprehensive overview.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300400}, pmid = {37726220}, issn = {1521-4028}, abstract = {Several resistance mechanisms are involved in dental caries, including oral biofilms. An accumulation of bacteria on the surface of teeth is called plaque. Periodontitis and gingivitis are caused by dental plaque. In this review article, we aimed to review the studies associated with the application of photodynamic therapy (PDT) to prevent and treat various microbial biofilm-caused oral diseases in recent decades. There are several studies published in PubMed that have described antimicrobial photodynamic therapy (APDT) effects on microorganisms. Several in vitro and in vivo studies have demonstrated the potential of APDT for treating endodontic, periodontal, and mucosal infections caused by bacteria as biofilms. Reactive oxygen species (ROS) are activated in the presence of oxygen by integrating a nontoxic photosensitizer (PS) with appropriate wavelength visible light. By causing irreversible damage to microorganisms, ROS induces some biological and photochemical events. Testing several wavelengths has been conducted to identify potential PS for APDT. A standard protocol is not yet available, and the current review summarizes findings from dental studies on APDT.}, } @article {pmid37724900, year = {2023}, author = {Sterzenbach, T and Hannig, C and Hertel, S}, title = {Influence of Consumption of Nitrate-rich Beetroot Juice on Lactate Production in Saliva and Oral Biofilm - A Clinical Trial.}, journal = {Oral health & preventive dentistry}, volume = {21}, number = {1}, pages = {297-306}, doi = {10.3290/j.ohpd.b4356487}, pmid = {37724900}, issn = {1757-9996}, abstract = {PURPOSE: Diets rich in nitrates have the potential to prevent oral diseases such as caries or periodontitis. The reduced forms nitrite and nitric oxide have an antibacterial effect against cariogenic bacteria. The effect on bacterial acid production in saliva and oral biofilm is yet unknown. This study investigated the influence of consuming naturally nitrate-rich beetroot juice on bacterial lactate production in saliva and on the pH value of saliva and oral biofilm.

MATERIALS AND METHODS: In addition to their usual diet, a study group of eight subjects consumed 50 ml of beetroot juice daily for a fortnight. After a two-week break, they rinsed with 0.2% chlorhexidine (CHX) for 14 days as a positive control. Bacterial lactate production was induced by rinsing with 50 ml apple juice and measured at different time points during the study.

RESULTS: After two weeks of daily beetroot-juice consumption, an accumulation of nitrate and nitrite was measured in the saliva. No influence on the bacterial lactate production in saliva or the saliva and plaque pH was found.

CONCLUSION: Commercially available beetroot juice showed no modulating effects on intraoral bacterial acid production, suggesting no caries-preventive properties under the tested conditions.}, } @article {pmid37724509, year = {2023}, author = {Neu, TR and Kuhlicke, U and Karwautz, C and Lüders, T}, title = {Unique architecture of microbial snottites from a methane driven biofilm revealed by confocal microscopy.}, journal = {Microscopy research and technique}, volume = {}, number = {}, pages = {}, doi = {10.1002/jemt.24422}, pmid = {37724509}, issn = {1097-0029}, support = {//Helmholtz-Gemeinschaft/ ; }, abstract = {Microbial biofilms occur in many shapes and different dimensions. In natural and semi-artificial caves they are forming pendulous structures of 10 cm and more. In this study a methane driven microbial community of a former medicinal spring was investigated. The habitat was completely covered by massive biofilms and snottites with a wobbly, gelatinous appearance. By using fluorescence techniques in combination with confocal laser scanning microscopy the architecture of these so far unknown snottites was examined. The imaging approaches applied comprised reflection of geogenic and cellular origin, possible autofluorescence, nucleic acid staining for bacterial cells, protein staining for bacteria and extracellular fine structures, calcofluor white for β 1 → 3, β 1 → 4 polysaccharide staining for possible fungi as well as lectin staining for the extracellular biofilm matrix glycoconjugates. The results showed a highly complex, intricate structure with voluminous, globular, and tube-like glycoconjugates of different dimensions and densities. In addition, filamentous bacteria seem to provide additional strength to the snottites. After screening with all commercially available lectins, by means of fluorescence lectin barcoding and subsequent fluorescence lectin binding analysis, the AAL, PNA, LEA, and Ban lectins identified α-Fuc, β-Gal, β-GlcNAc, and α-Man with α-Fuc as a major component. Examination of the outer boundary with fluorescent beads revealed a potential outer layer which could not be stained by any of the fluorescent probes applied. Finally, suggestions are made to further elucidate the characteristics of these unusual microbial biofilms in form of snottites. RESEARCH HIGHLIGHTS: The gelatinous snottites revealed at the microscale a highly complex structure not seen before. The extracellular matrix of the snottite biofilm was identified as clusters of different shape and density. The matrix of snottites was examined by taking advantage of 78 fluorescently-labeled lectins. The extracellular matrix glycoconjugates of snottites identified comprised: α-Fuc, β-Gal, β-GlcNAc, and α-Man. Probing the snottite outer surface indicated an additional unknown stratum.}, } @article {pmid37723466, year = {2023}, author = {Nouruzi, E and Hosseini, SM and Asghari, B and Mahjoub, R and Zare, EN and Shahbazi, MA and Kalhori, F and Arabestani, MR}, title = {Effect of poly (lactic-co-glycolic acid) polymer nanoparticles loaded with vancomycin against Staphylococcus aureus biofilm.}, journal = {BMC biotechnology}, volume = {23}, number = {1}, pages = {39}, pmid = {37723466}, issn = {1472-6750}, support = {140007276055//The Vice Chancellor for research and technology, Hamadan university of medical sciences, Hamadan/Iran/ ; }, abstract = {Staphylococcus aureus is a unique challenge for the healthcare system because it can form biofilms, is resistant to the host's immune system, and is resistant to numerous antimicrobial therapies. The aim of this study was to investigate the effect of poly (lactic-co-glycolic acid) (PLGA) polymer nanoparticles loaded with vancomycin and conjugated with lysostaphin (PLGA-VAN-LYS) on inhibiting S. aureus biofilm formation. Nano drug carriers were produced using the double emulsion evaporation process. we examined the physicochemical characteristics of the nanoparticles, including particle size, polydispersity index (PDI), zeta potential, drug loading (DL), entrapment efficiency (EE), Lysostaphin conjugation efficiency (LCE), and shape. The effect of the nano drug carriers on S. aureus strains was evaluated by determining the minimum inhibitory concentration (MIC), conducting biofilm formation inhibition studies, and performing agar well diffusion tests. The average size, PDI, zeta potential, DL, EE, and LCE of PLGA-VAN-LYS were 320.5 ± 35 nm, 0.270 ± 0.012, -19.5 ± 1.3 mV, 16.75 ± 2.5%, 94.62 ± 2.6%, and 37% respectively. Both the agar well diffusion and MIC tests did not show a distinction between vancomycin and the nano drug carriers after 72 h. However, the results of the biofilm analysis demonstrated that the nano drug carrier had a stronger inhibitory effect on biofilm formation compared to the free drug. The use of this technology for treating hospital infections caused by the Staphylococcus bacteria may have favorable effects on staphylococcal infections, considering the efficacy of the nano medicine carrier developed in this study.}, } @article {pmid37722473, year = {2023}, author = {Li, D and Guo, W and Zhai, Y and Xu, X and Cao, X and Zhao, L}, title = {The aggregated biofilm dominated by Delftia tsuruhatensis enhances the removal efficiency of 2,4-dichlorophenol in a bioelectrochemical system.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122576}, doi = {10.1016/j.envpol.2023.122576}, pmid = {37722473}, issn = {1873-6424}, abstract = {Bioelectrochemical system is a prospective strategy in organic-contaminated groundwater treatment, while few studies clearly distinguish the mechanisms of adsorption or biodegradation in this process, especially when dense biofilm is formed. This study employed a single chamber microbial electrolysis cell (MEC) with two three-dimensional electrodes for removing a typical organic contaminant, 2,4-dichlorophenol (DCP) from groundwater, which inoculated with anaerobic bacteria derived from sewage treatment plant. Compared with the single biodegradation system without electrodes, the three-dimensional electrodes with a high surface enabled an increase of alpha diversity of the microbial community (increased by 52.6% in Shannon index), and provided adaptive ecological niche for more bacteria. The application of weak voltage (0.6 V) furtherly optimized the microbial community structure, and promoted the aggregation of microorganisms with the formation of dense biofilm. Desorption experiment proved that the contaminants were removed from the groundwater mainly via adsorption by the biofilm rather than biodegradation, and compared with the reactor without electricity, the bioelectrochemical system increased the adsorption capacity from 50.0% to 74.5%. The aggregated bacteria on the surface of electrodes were mainly dominated by Delftia tsuruhatensis (85.0%), which could secrete extracellular polymers and has a high adsorption capacity (0.30 mg/g electrode material) for the contaminants. We found that a bioelectrochemical system with a three-dimensional electrode could stimulate the formation of dense biofilm and remove the organic contaminants as well as their possible more toxic degradation intermediates via adsorption. This study provides important guidance for applying bioelectrochemical system in groundwater or wastewater treatment.}, } @article {pmid37722186, year = {2023}, author = {Carmona-Orozco, ML and Quiñones, W and Robledo, SM and Torres, F and Echeverri, F}, title = {Reversing the biofilm-inducing effect of two xanthones from Garcinia mangostana by 3-methyl-2(5H)-furanone and N-butyryl-D-L homoserine lactone.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {120}, number = {}, pages = {155069}, doi = {10.1016/j.phymed.2023.155069}, pmid = {37722186}, issn = {1618-095X}, abstract = {BACKGROUND: According to the WHO, 12 bacteria cause numerous human infections, including Enterobacteriaceae Klebsiella pneumoniae, and thus represent a public health problem. Microbial resistance is associated with biofilm formation; therefore, it is critical to know the biofilm-inducing potential of various compounds of everyday life. Likewise, the reversibility of biofilms and the modulation of persister cells are important for controlling microbial pathogens. In this work, we investigated the biofilm-inducing effects of xanthones from Garcinia mangostana on Klebsiella pneumoniae. Furthermore, we investigated the reversal effect of 3-methyl-2(5H)-furanone and the formation of persister cells induced by xanthones and their role in modulating the biofilm to the antibiotic gentamicin.

METHODS: To analyze the biofilm-inducing role of xanthones from Garcinia mangostana, cultures of K. pneumoniae containing duodenal probe pieces were treated with 0.1-0.001 μM α- and γ-mangostin, and the biofilm levels were measured using spectrophotometry. To determine biofilm reversion, cultures treated with xanthones, or gentamicin were mixed with 3-methyl-2(5H)-furanone or N-butyryl-DL-homoserine lactone. The presence of K. pneumoniae persister cells was determined by applying the compounds to the mature biofilm, and the number of colony-forming units was counted.

RESULTS: The xanthones α- and γ-mangostin increased K. pneumoniae biofilm production by 40% with duodenal probes. However, 3-methyl-2(5H)-furanone at 0.001 μΜ reversed biofilm formation by up to 60%. Moreover, adding the same to a culture treated with gentamicin reduced the biofilm by 80.5%. This effect was highlighted when 3-methyl-2(5H)-furanone was administered 6 h later than xanthones. At high concentrations of α-mangostin, persister K. pneumoniae cells in the biofilm were about 5 - 10 times more abundant than cells, whereas, with γ-mangostin, they were about 100 times more.

CONCLUSION: Two xanthones, α- and γ-mangostin from G. mangostana, induced biofilm formation in K. pneumoniae and promoted persister cells. However, the biofilm formation was reversed by adding 3-methyl-2(5H)-furanone, and even this effect was achieved with gentamicin. In addition, this compound controlled the persister K. pneumoniae cells promoted by α-mangostin. Thus, synthetic, and natural biofilm-inducing compounds could harm human health. Therefore, avoiding these substances and looking for biofilm inhibitors would be a strategy to overcome microbial resistance and recover antibiotics that are no longer used.}, } @article {pmid37720478, year = {2023}, author = {Chen, W and Xu, Z and Li, C and Wang, C and Wang, M and Liang, J and Wei, P}, title = {Investigation of biofilm formation and the associated genes in multidrug-resistant Salmonella pullorum in China (2018-2022).}, journal = {Frontiers in veterinary science}, volume = {10}, number = {}, pages = {1248584}, pmid = {37720478}, issn = {2297-1769}, abstract = {The study explored the biofilm (BF) formation capacity, BF-related gene profiles, and the trends in antimicrobial resistance (AMR) of Salmonella pullorum (SP) strains over several years. A total of 627 SP strains were isolated from 4,540 samples collected from chicken farms in Guangxi, China during 2018-2022. The BF-forming capacity of these isolates was assessed using crystal violet staining, and the presence of eight BF-related genes (csgA, csgB, csgD, ompR, bapA, pfs, luxS, and rpoS) in BF formation-positive strains was determined through Polymerase Chain Reaction (PCR) analysis. Antimicrobial susceptibility test was conducted to investigate the AMR of the isolates. Minimum Inhibitory Concentration (MIC) and Minimal Biofilm Eradication Concentration (MBEC) of nine SP-BF strains were determined using the broth microdilution method to assess the impact of BF formation on AMR. Additionally, the Optimal Biofilm Formation Conditions (OBFC) were investigated. The results indicated that 36.8% (231/627) of the strains exhibited a positive BF-formation capacity. Among these, 24.7% (57/231) were strong BF producers, 23.4% (54/231) were moderate BF producers, and 51.9% (120/231) were weak BF producers. Analysis of the eight BF-related genes in SP-BF strains revealed that over 90% of them were positive for all the genes. Antimicrobial susceptibility test conducted on the isolates showed that 100% (231/231) of them exhibited resistance to at least one antibiotic, with 98.3% (227/231) demonstrating multidrug resistance (MDR). Both MIC and MBEC measurements indicated varying degrees of increased AMR after BF formation of the bacteria. The optimal conditions for BF formation were observed at 37°C after 48 h of incubation, with an initial bacterial concentration of 1.2 × 10[6] CFU/mL. Notably, NaCl had a significant inhibitory effect on BF formation, while glucose and Trypticase Soy Broth (TSB) positively influenced BF formation. The results of the study emphasized the need for effective preventive and control strategies to address the challenges posed by the BF formation and MDR of SP in the field.}, } @article {pmid37720037, year = {2023}, author = {Zylla, JL and Z, EG and Bomgni, AB and Sani, RK and Subramaniam, M and Lushbough, C and Winter, R and Gadhamshetty, VR and Chundi, P}, title = {Convergence research and training in computational bioengineering: a case study on AI/ML driven biofilm-material interaction discovery.}, journal = {Research square}, volume = {}, number = {}, pages = {}, doi = {10.21203/rs.3.rs-3318640/v1}, pmid = {37720037}, abstract = {Initially, research disciplines operated independently, but the emergence of trans- disciplinary sciences led to convergence research, impacting graduate programs and research laboratories, especially in bioengineering and material engineering as presented here. Current graduate curriculum fails to efficiently prepare students for multidisciplinary and convergence research, thus creating a gap between the students and research laboratory expectations. We present a convergence training framework for graduate students, incorporating problem-based learning under the guidance of senior scientists and collaboration with postdoctoral researchers. This case study serves as a template for transdisciplinary convergent training projects - bridging the expertise gap and fostering successful convergence learning experiences in computational biointerface (material-biology interface). The 18-month Advanced Data Science Workshop, initiated in 2019, involves project-based learning, online training modules, and data collection. A pilot solution utilized Jupyter notebook on Google collaborator and culminated in a face-to-face workshop where project presentations and finalization occurred. The program started with 9 experts in the four diverse fields creating 14 curated projects in data science (Artificial Intelligence/Machine Learning), material science, biofilm engineering, and biointerface. These were integrated into convergence research through webinars by the experts. The experts chose 8 of the 14 projects to be part of an all-day in-person workshop, where over 20 learners formed eight teams that tackled complex problems at the interface of digital image processing, gene expression analysis, and material prediction. Each team was comprised of students and postdoctoral researchers or research scientists from diverse domains including computer science, materials science, and biofilm research. Some projects were selected for presentation at the international IEEE Bioinformatics conference in 2022, with three resulting Machine Learning (ML) models submitted as a journal paper. Students engaged in problem discussions, collaborated with experts from different disciplines, and received guidance in decomposing learning objectives. Based on learner feedback, this successful experience allows for consolidation and integration of convergence research via problem-based learning into the curriculum. Three bioengineering participants, who received training in data science and engineering, have received bioinformatics jobs in biotechnology industries.}, } @article {pmid37719934, year = {2023}, author = {Ruchiatan, K and Rizqandaru, T and Satjamanggala, PR and Tache, N and Cahyadi, AI and Rezano, A and Gunawan, H and Sutedja, EK and Dwiyana, RF and Hidayah, RMN and Achdiat, PA and Sutedja, E and Suwarsa, O and Hindritiani, R}, title = {Characteristics of Biofilm-Forming Ability and Antibiotic Resistance of Cutibacterium acnes and Staphylococcus epidermidis from Acne Vulgaris Patients.}, journal = {Clinical, cosmetic and investigational dermatology}, volume = {16}, number = {}, pages = {2457-2465}, doi = {10.2147/CCID.S422486}, pmid = {37719934}, issn = {1178-7015}, abstract = {INTRODUCTION: Acne vulgaris (AV) is a common and chronic disorder of the pilosebaceous unit and has a multifactorial pathology, including activities of Cutibacterium acnes (C. acnes) and Staphylococcus epidermidis (S. epidermidis). Antibiotic resistance has become a major concern in dermatology daily practice, and the ability of biofilm formation by both bacteria is suggested to increase antibiotic resistance in acne.

PURPOSE: Our aim was to analyze the comparison of antibiotic resistance between biofilm-forming (BF) and non-biofilm-forming (NBF) strains of C. acnes and S. epidermidis towards seven antibiotics commonly used for acne.

METHODS: This is a cross-sectional analytical study involving 60 patients with AV. Samples were obtained from closed comedones on the forehead using the standardized skin surface biopsy (SSSB) method at the Cosmetic Dermatology Clinic Dr. Hasan Sadikin in Bandung, Indonesia. Isolates were cultured and identified before undergoing the biofilm-forming test using the tissue culture plate method. Antibiotic susceptibility testing for each antibiotic was then performed using the disc diffusion method.

RESULTS: The incidence of antibiotic resistance to clindamycin in BF and NBF C. acnes isolates was 54.5% (p=1.00), while in BF and NBF S. epidermidis isolates, it was 54.5% and 45.5% respectively (p=0.67). The incidence of antibiotic resistance to erythromycin and azithromycin in BF and NBF C. acnes isolates was 54.5% and 63.6% respectively (p=1.00), whereas for S. epidermidis BF and NBF isolates, it was 54.5% (p=1.00). There was no resistance observed to tetracycline, doxycycline, levofloxacin, and cotrimoxazole in all groups.

CONCLUSION: There were no significant differences in resistance against seven antibiotics between the C. acnes and S. epidermidis in BF and NBF groups. Furthermore, although statistically not significant, some resistances were observed against clindamycin, erythromycin, and azithromycin. Consequently, the use of these three antibiotics should be judiciously regulated.}, } @article {pmid37717901, year = {2023}, author = {Samadi, A and Kermanshahi Pour, A and Gagnon, G}, title = {Biodegradation of 1,4-dioxane in a continuous-flow bioelectrochemical reactor by biofilm of Pseudonocardia dioxanivorans CB1190 and microbial community on conductive carriers.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122572}, doi = {10.1016/j.envpol.2023.122572}, pmid = {37717901}, issn = {1873-6424}, abstract = {Bioelectrochemical degradation is an environmentally friendly, cost-effective and controllable way of providing electron acceptor to the microorganisms. A two-chamber continuous-flow bioelectrochemical reactor (BER) was developed in this study. The objective was to investigate the potential for enhancing the bioelectrochemical degradation of 1,4-dioxane (DX) by Pseudonocardia dioxanivorans CB1190 (CB1190) and microbial community biofilm on conductive and non-conductive carriers in low potentials (1.0-1.2 V) and currents (<2 mA). In the case of CB1190, biodegradation experiments at 1.0 V did not result in any observable change in DX removal efficiency (32.63 ± 2.48%) compared to the 0.0 V (31.69 ± 2.33%). However, the removal efficiency was much higher at 1.2 V (59.08 ± 0.86%). The higher removal at 1.2 V was attributed to an increase in dissolved oxygen (DO) concentration from 3.77 ± 0.33 mg/L at 0.0 V to 5.40 ± 0.11 mg/L at 1.2 V, which resulted from water electrolysis. In the case of microbial community, on the other hand, DX removal efficiency increased at 1.0 V (30.98 ± 1.10%) compared to 0.0 V (23.40 ± 1.02%) that can be attributed to a simultaneous increase in microbial activity from 2389 ± 118.5 ngATP/mgVSS at 0.0 V to 2942 ± 109 ngATP/mgVSS at 1.0 V. Analysis of the changes in microbial composition indicated enrichment of Alistipes and Lutispora at 1.0 V due to the ability of these genera to directly transfer electrons with conductive surface. On the other hand, no change was observed in the microbial community in the case of non-conductive carriers. Results of this study showed that electro-assisted biodegradation of DX at low potentials is possible through two different mechanisms (oxygen production and direct electron transfer with electrode) which makes this technique flexible and cost-effective. The novelty of this work lies in exploring the use of electrical assistance to enhance the biodegradation of DX in the presence of CB1190 and the microbial community. This study more specifically investigated lower potential than required water electrolysis potential, allowing microorganisms to be stimulated through mechanisms unrelated to oxygen generation.}, } @article {pmid37717335, year = {2023}, author = {Meng, F and Guo, S and Zhang, L and Lu, Y and Li, M and Tan, Y and Zha, K and Yuan, S}, title = {Ecological mechanisms of biofilm development in the hybrid sludge-biofilm process: Implications for process start-up and optimization.}, journal = {Water research}, volume = {245}, number = {}, pages = {120587}, doi = {10.1016/j.watres.2023.120587}, pmid = {37717335}, issn = {1879-2448}, abstract = {The hybrid sludge-biofilm processes have been widely applied for the construction or upgradation of biological wastewater treatment process. Ecological mechanisms of biofilm development remain unclear in the hybrid ecosystem, because of the intricate interactive effects between sludge and biofilms. Herein, the establishment principles of biofilms with distinct coexisting sludge amounts were uncovered by varying sludge retention times (SRTs) from 5 to 40 days in the hybrid process. With the increasing of SRTs, biofilm biomass decreased with the increase of suspended sludge, resulting in lower biofilm proportion. As estimated by the Gompertz growth model, the increased sludge amounts (i.e., higher SRTs of 20 and 40 days) prolonged the initial colonization stage and decreased the specific development rate of biofilms when compared to lower sludge amounts with the shorter SRTs (i.e., 5 and 10 days). Null model analysis demonstrated that deterministic homogenous selection could facilitate the colonization and accumulation of biofilms with less coexisting sludge (SRT of 10 days). However, stochastic ecological drift and homogenizing dispersal dominated the colonization and accumulation stages of biofilms with more coexisting sludge (SRT of 20 days), respectively. The ecological networks reflected that positively-related taxa presented taxonomic relatedness, whereas high inconsistency of taxonomic relatedness was observed among aggregate forms or development stages as affected by varied SRTs. The high incidence of intra-taxa co-occurrence patterns suggested that taxa with similar ecological niches could be specifically selected in biofilms when being exposed with less coexisting sludge. This study uncovered ecological mechanisms of biofilm development driven by varying the SRTs of suspended sludge, which would help to propose appropriate strategies for the efficient start-up and optimization of the hybrid sludge-biofilm system.}, } @article {pmid37717325, year = {2023}, author = {Sandeep, R and Muscolino, JF and Macêdo, WV and Piculell, M and Christensson, M and Poulsen, JS and Nielsen, JL and Vergeynst, L}, title = {Effect of biofilm thickness on the activity and community composition of phosphorus accumulating bacteria in a moving bed biofilm reactor.}, journal = {Water research}, volume = {245}, number = {}, pages = {120599}, doi = {10.1016/j.watres.2023.120599}, pmid = {37717325}, issn = {1879-2448}, abstract = {Can biofilms enhance the rates of phosphorus removal in wastewater treatment? In order to narrow the scientific gap on the effect of biofilm thickness on the activity and microbial community of phosphorus-accumulating bacteria, this study investigated biofilms of 30 to 1000 µm thickness in a moving bed biofilm reactor. Measurements on 5 different biofilm carriers showed that biomass-specific phosphorus release and uptake rates increased as a function of biofilm thickness for biofilms thinner than about 110 µm but were lower for thicker biofilms of about 550-1000 µm. The reduced phosphorus uptake and release rates in the thickest biofilms can result from substrate mass transfer limitations whereas the low activity in the thinnest biofilms can be related to a too high turnover rate in the biofilm due to heterotrophic growth. Additionally, the microbial ecology of the different biofilms confirms the observed phosphorus uptake and release rates. The results from the full-length 16S rRNA gene sequencing of the bacterial community showed that the thicker biofilms were characterized by higher relative abundance (40-58%) of potential phosphorus accumulating genera Zoogloea, Acinetobacter, Dechloromonas and Ca. Accumulibacter. In contrast, the thinner biofilms were dominated by the genus Ferribacterium (34-60%), which might be competing with phosphorus-accumulating bacteria as indicated by the relatively high acetate uptake rates in the thinner biofilms. It is concluded that there is an optimal biofilm thickness of 100-500 µm, at which the phosphorus accumulating bacteria have the highest activity.}, } @article {pmid37718461, year = {2023}, author = {Lichtenberg, M and Kirketerp-Møller, K and Kvich, LA and Christensen, MH and Fritz, B and Jakobsen, TH and Bjarnsholt, T}, title = {Single cells and bacterial biofilm populations in chronic wound infections.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13344}, pmid = {37718461}, issn = {1600-0463}, abstract = {Chronic wounds and chronic ulcers are an increasing problem associated with high health care burden and patient burden. The arrested healing of chronic wounds has, in part, been attributed to the presence of biofilms. Substantial research has documented the presence of biofilms in chronic wounds, and many mechanisms of host-pathogen interactions have been uncovered to explain the arrested healing. However, the paradigm of whether biofilms are only observed in chronic infections was recently challenged when biofilms were also observed in acute infections. Here, we characterize the distribution of bacteria in lower leg wounds with particular emphasis on Pseudomonas aeruginosa and Staphylococcus aureus by confocal laser scanning microscopy combined with PNA-FISH staining and routine culture of bacteria. We show that 40% of wounds contained either P. aeruginosa or S. aureus biofilms and demonstrate the presence of scattered single cells in tissues stained with a universal bacterial PNA-FISH probe. Thus, we demonstrate that chronic wounds do not only harbor bacteria organized in biofilms, but also carry populations of scattered single cells and small cell clusters of only a few bacteria. Our findings may influence diagnostic tools being developed to only target biofilms, where single-cell subpopulations thus may be overlooked and possibly lead to false-negative results.}, } @article {pmid37716444, year = {2023}, author = {Bandyopadhyay, NC and Gautam, S}, title = {Programmed cell death in Xanthomonas axonopodis pv. glycines is associated with modulation of gene expression resulting in altered states of motility, biofilm and virulence.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104137}, doi = {10.1016/j.resmic.2023.104137}, pmid = {37716444}, issn = {1769-7123}, abstract = {One of the foremost report of apoptosis-like programmed cell death (PCD) came from Xanthomonas axonopodis pv. glycines (Xag), which displayed rapid post-exponential cell death in PCD inducing media (PIM) but not in a non-inducing media (PNIM). The current study aims to decipher for the first time, the advantages of the existence of PCD in this phytopathogenic microorganism. Analysis of RNA seq under inducing and non-inducing conditions, revealed differential expression of a number of genes related to key physiology of Xag, such as, motility, xanthan biosynthesis and export as well as virulence. A PCD negative mutant Xag M42 displayed diminished virulence and a contrasting transcriptome pattern. In vitro experiments revealed that under PCD inducing condition, Xag produced negligible xanthan gum as well as extracellular amylase, displayed enhanced swarming motility, released copious e-DNA and formed scanty biofilm. Lack of 'diffusible signalling factor' production was eliminated as possible reason for PCD-induction. Altogether, it appears that, in planta existence of the pathogen metabolically resembles PNIM, and on being transferred to PIM, the cells experience oxidative stress and circumvents it by adopting PCD as an altruistic response. Survival of the remaining population is encouraged by upregulating motility, detachment from the fragile biofilm to achieve dispersal.}, } @article {pmid37715894, year = {2023}, author = {Yang, M and Li, Z}, title = {Development of Green-Synthesized Carbon-Based Nanoparticle for Prevention of Surface Wound Biofilm.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37715894}, issn = {1559-0291}, abstract = {The development of microbial biofilm occurs with the adherence of the microbial cells on biotic and abiotic surfaces with the help of pili and with extracellular polymeric substances. The surfaces on which biofilm formation take place can be inert, abiotic, or biotic. The sessile microbial cells behave differently from their planktonic counterpart. The biofilm developed by Alcaligenes faecalis is responsible for the development of skin and soft-tissue infection. It was observed that green-synthesized carbon nanoparticles (NPs) from Ocimum sanctum showed a prolonged stability and activity. It showed a marked reduction in the viability of sessile microbial species with least revival in comparison to the plant extract and amoxicillin. It was observed that carbon NP was able to maximally reduce the quorum sensing (QS) activity of A. faecalis. Thus, the use of green-synthesized NPs would be an alternative in the treatment of the biofilm-associated chronic wound infections.}, } @article {pmid37715865, year = {2023}, author = {Radojević, ID and Jakovljević, VD and Ostojić, AM}, title = {A mini-review on indigenous microbial biofilm from various wastewater for heavy-metal removal - new trends.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {11}, pages = {309}, pmid = {37715865}, issn = {1573-0972}, support = {451-03-47/2023-01/ 200122//Serbian Ministry of Science, Technological Development and Innovation/ ; ECOSTSTSM-Request-CA18113-45768//COST Action 18113 EuroMicropH Understanding and exploiting the impacts of low pH on micro-organisms/ ; }, abstract = {Biofilm, as a form of the microbial community in nature, represents an evolutionary adaptation to the influence of various environmental conditions. In nature, the largest number of microorganisms occur in the form of multispecies biofilms. The ability of microorganisms to form a biofilm is one of the reasons for antibiotic resistance. The creation of biofilms resistant to various contaminants, on the other hand, improves the biological treatment process in wastewater treatment plants. Heavy metals cannot be degraded, but they can be transformed into non-reactive and less toxic forms. In this process, microorganisms are irreplaceable as they interact with the metals in a variety of ways. The environment polluted by heavy metals, such as wastewater, is also a source of undiscovered microbial diversity and specific microbial strains. Numerous studies show that biofilm is an irreplaceable strategy for heavy metal removal. In this review, we systematize recent findings regarding the bioremediation potential of biofilm-forming microbial species isolated from diverse wastewaters for heavy metal removal. In addition, we include some mechanisms of action, application possibilities, practical issues, and future prospects.}, } @article {pmid37715042, year = {2023}, author = {Candry, P and Chadwick, GL and Caravajal-Arroyo, JM and Lacoere, T and Winkler, MH and Ganigué, R and Orphan, VJ and Rabaey, K}, title = {Trophic interactions shape the spatial organization of medium-chain carboxylic acid producing granular biofilm communities.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, pmid = {37715042}, issn = {1751-7370}, support = {BOF15/DOC/286//Bijzonder Onderzoeksfonds (Special Research Fund)/ ; BOF19/STA/044//Bijzonder Onderzoeksfonds (Special Research Fund)/ ; #DE-SC0020356//DOE | SC | Biological and Environmental Research (BER)/ ; #DE-SC0020373//DOE | SC | Biological and Environmental Research (BER)/ ; #DE-SC0020373//DOE | SC | Biological and Environmental Research (BER)/ ; }, abstract = {Granular biofilms producing medium-chain carboxylic acids (MCCA) from carbohydrate-rich industrial feedstocks harbor highly streamlined communities converting sugars to MCCA either directly or via lactic acid as intermediate. We investigated the spatial organization and growth activity patterns of MCCA producing granular biofilms grown on an industrial side stream to test (i) whether key functional guilds (lactic acid producing Olsenella and MCCA producing Oscillospiraceae) stratified in the biofilm based on substrate usage, and (ii) whether spatial patterns of growth activity shaped the unique, lenticular morphology of these biofilms. First, three novel isolates (one Olsenella and two Oscillospiraceae species) representing over half of the granular biofilm community were obtained and used to develop FISH probes, revealing that key functional guilds were not stratified. Instead, the outer 150-500 µm of the granular biofilm consisted of a well-mixed community of Olsenella and Oscillospiraceae, while deeper layers were made up of other bacteria with lower activities. Second, nanoSIMS analysis of [15]N incorporation in biofilms grown in normal and lactic acid amended conditions suggested Oscillospiraceae switched from sugars to lactic acid as substrate. This suggests competitive-cooperative interactions may govern the spatial organization of these biofilms, and suggests that optimizing biofilm size may be a suitable process engineering strategy. Third, growth activities were similar in the polar and equatorial biofilm peripheries, leaving the mechanism behind the lenticular biofilm morphology unexplained. Physical processes (e.g., shear hydrodynamics, biofilm life cycles) may have contributed to lenticular biofilm development. Together, this study develops an ecological framework of MCCA-producing granular biofilms that informs bioprocess development.}, } @article {pmid37714492, year = {2023}, author = {Wu, G and Yang, G and Sun, X and Li, B and Tian, Z and Niu, X and Cheng, J and Feng, L}, title = {Simultaneous denitrification and organics removal by denitrifying bacteria inoculum in a multistage biofilm process for treating desulfuration and denitration wastewater.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129757}, doi = {10.1016/j.biortech.2023.129757}, pmid = {37714492}, issn = {1873-2976}, abstract = {This study aimed to treat real wastewater from the desulfuration and denitration process in a petrochemical plant with high-strength nitrogen (TN≈200 mg/L, >90% nitrate), sulfate (2.7%) and extremely low-strength organics (CODCr < 30 mg/L). Heterotrophic denitrification of multistage anoxic and oxic biofilm (MAOB) process in three tanks using facultative denitrifying bacteria inoculum was developed to simultaneously achieving desirable effluent nitrogen and organics at different hydraulic retention time (HRT) and carbon to nitrogen (C/N) mass ratios. The optimum condition was recommended as a C/N ratio of 1.5 and a HRT of A (24 h)/O (12-24 h) to achieve > 90% of nitrogen and organics removal as well as no significant variation of sulfate. The denitrifying biofilm in various tanks was dominant by Hyphomicrobium (8.9%-25.7%), Methylophaga (18.6%-25.8%) and Azoarcus (3.3%-19.6%), etc., containing > 20% aerobic denitrifiers. This explained that oxic zone in MAOB process also exhibited simultaneous nitrogen and organics removal.}, } @article {pmid37714481, year = {2023}, author = {Zhao, Z and Sun, Y and Wang, H and Yu, Q}, title = {Regulation of cadmium-induced biofilm formation by artificial polysaccharide-binding proteins for enhanced phytoremediation.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140156}, doi = {10.1016/j.chemosphere.2023.140156}, pmid = {37714481}, issn = {1879-1298}, abstract = {Phytoremediation is an economic way to attenuate soil heavy metal pollution, but is frequently limited by its low pollutant-removing efficiency. Recently, we revealed the close relation between polysaccharide-based biofilm formation and cadmium removal. In this study, for improving the phytoremediation efficiency, an artificial polysaccharide-binding protein was designed by synthetic biology techniques to regulate biofilm formation. The artificial protein Syn contained two polysaccharide-binding domains from the Ruminococcus flavefaciens CttA and the Clostridium cellulolyticum CipC, preferentially binding polysaccharides exposed on both cadmium-treated bacteria and plant roots. Under cadmium stress, Syn remarkably promoted bacterial polysaccharide production from 99 mg/L to 237 mg/L, leading to 1.23-fold higher biofilm biomass. During treatment of the remediation plants with exogenous cadmium-capturing bacteria, Syn improved root biofilm formation, with the root surface polysaccharide contents increasing by 79%, and the Log10 CFU/g root increasing from 7.01 to 7.80. Meanwhile, Syn remodeled the rhizosphere microbiome, especially increasing the abundance of the bacterial groups involved in biofilm formation and stress tolerance, e.g., Pseudomonas, Enterobacter, etc. Consequently, Syn promoted plant cadmium adsorption, with the cadmium-removing efficiency increasing from 17.2% to 33.8%. This study sheds light on synthetic biology-based regulation of biofilm formation for enhanced phytoremediation.}, } @article {pmid37714352, year = {2023}, author = {Tang, L and Pan, Z and Li, X and Li, J and Meng, J}, title = {Antibiotics resistance removal from piggery wastewater by an integrated anaerobic-aerobic biofilm reactor: Efficiency and mechanism.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {167031}, doi = {10.1016/j.scitotenv.2023.167031}, pmid = {37714352}, issn = {1879-1026}, abstract = {Antibiotic resistance residual in piggery wastewater poses serious threat to environment and human health. Biological treatment process is commonly installed to remove nutrient from piggery wastewater and also effective in removing antibiotics to varying degrees. But the specific pathways and mechanisms involved in the removal of antibiotic resistance are not yet well-understood. An integrated anaerobic-aerobic biofilm reactor (IAOBR) has been demonstrated efficient in removing conventional nutrients. It is here shown that the IAOBR effectively removed 79.0 % of Sulfonamides, 55.7 % of Tetracyclines and 53.6 % of Quinones. Antibiotic resistance bacteria (ARB) were simultaneously inactivated by ~0.5 logs. Antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) were decreased by 0.51 logs and 0.42 logs, respectively. The antibiotics were mainly removed through aerobic compartments of the IAOBR. The mass loss of antibiotics in the reactor was achieved by biodegradation and adsorption, accounting for 52.1 % and 47.9 %, respectively. An obvious accumulation of ARGs was observed in the activated sludge. The potential host of ARGs was analyzed via microbial community and network. Partial least squares-structural equation model and correlation analysis revealed that the enrichment of ARGs was positively affected by MGEs, followed by bacterial community and ARBs, but the effect of antibiotics on ARGs was negative. Outcomes of this study provide valuable insights into the mechanisms of antibiotic resistance removal in biological treatment processes.}, } @article {pmid37712684, year = {2023}, author = {Ballah, FM and Islam, MS and Ievy, S and Ferdous, FB and Sobur, MA and Rahman, AT and Rahman, M and Haque, MN and Hassan, J and Rahman, MT}, title = {Draft genome sequence of biofilm-forming methicillin-resistant Staphylococcus aureus MTR_V1 strain isolated from a ready-to-eat food in Bangladesh.}, journal = {Microbiology resource announcements}, volume = {}, number = {}, pages = {e0059723}, doi = {10.1128/MRA.00597-23}, pmid = {37712684}, issn = {2576-098X}, abstract = {This announcement provides the genome sequence of the biofilm-forming methicillin-resistant Staphylococcus aureus MTR_V1 strain isolated from a ready-to-eat food sample in Bangladesh. Our assembled genome had a length of 2.8 Mb, 27 contigs, two CRISPR arrays, 38 predicted antibiotic resistance genes, and 66 predicted virulence factor genes.}, } @article {pmid37711848, year = {2023}, author = {Pongchaikul, P and Hajidariyor, T and Khetlai, N and Yu, YS and Arjfuk, P and Khemthong, P and Wanmolee, W and Posoknistakul, P and Laosiripojana, N and Wu, KC and Sakdaronnarong, C}, title = {Nanostructured N/S doped carbon dots/mesoporous silica nanoparticles and PVA composite hydrogel fabrication for anti-microbial and anti-biofilm application.}, journal = {International journal of pharmaceutics: X}, volume = {6}, number = {}, pages = {100209}, doi = {10.1016/j.ijpx.2023.100209}, pmid = {37711848}, issn = {2590-1567}, abstract = {Regarding the convergence of the worldwide epidemic, the appearance of bacterial infection has occasioned in a melodramatic upsurge in bacterial pathogens with confrontation against one or numerous antibiotics. The implementation of engineered nanostructured particles as a delivery vehicle for antimicrobial agent is one promising approach that could theoretically battle the setbacks mentioned. Among all nanoparticles, silica nanoparticles have been found to provide functional features that are advantageous for combatting bacterial contagion. Apart from that, carbon dots, a zero-dimension nanomaterial, have recently exhibited their photo-responsive property to generate reactive oxygen species facilitating to enhance microorganism suppression and inactivation ability. In this study, potentials of core/shell mesoporous silica nanostructures (MSN) in conjugation with carbon dots (CDs) toward antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli have been investigated. Nitrogen and sulfur doped CDs (NS/CDs) conjugated with MSN which were cost effective nanoparticles exhibited much superior antimicrobial activity for 4 times as much as silver nanoparticles against all bacteria tested. Among all nanoparticles tested, 0.40 M NS/CDs@MSN showed the greatest minimal biofilm inhibitory at very low concentration (< 0.125 mg mL[-1]), followed by 0.20 M NS/CDs@MSN (0.5 mg mL[-1]), CD@MSN (25 mg mL[-1]), and MSN (50 mg mL[-1]), respectively. Immobilization of NS/CDs@MSN in polyvinyl alcohol (PVA) hydrogel was performed and its effect on antimicrobial activity, biofilm controlling efficiency, and cytotoxicity toward fibroblast (NIH/3 T3 and L-929) cells was additionally studied for further biomedical applications. The results demonstrated that 0.40 M NS/CDs-MSN@PVA hydrogel exhibited the highest inhibitory effect on S. aureus > P. aeruginosa > E. coli. In addition, MTT assay revealed some degree of toxicity of 0.40 M NS/CDs-MSN@PVA hydrogel against L-929 cells by a slight reduction of cell viability from 100% to 81.6% when incubated in the extract from 0.40 M NS/CDs-MSN@PVA hydrogel, while no toxicity of the same hydrogel extract was detected toward NIH/3 T3 cells.}, } @article {pmid37711514, year = {2023}, author = {Trognon, J and Rima, M and Lajoie, B and Roques, C and El Garah, F}, title = {NaCl-induced modulation of species distribution in a mixed P. aeruginosa / S. aureus /B.cepacia biofilm.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100153}, doi = {10.1016/j.bioflm.2023.100153}, pmid = {37711514}, issn = {2590-2075}, abstract = {Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia are notorious pathogens known for their ability to form resilient biofilms, particularly within the lung environment of cystic fibrosis (CF) patients. The heightened concentration of NaCl, prevalent in the airway liquid of CF patients' lungs, has been identified as a factor that promotes the growth of osmotolerant bacteria like S. aureus and dampens host antibacterial defenses, thereby fostering favorable conditions for infections. In this study, we aimed to investigate how increased NaCl concentrations impact the development of multi-species biofilms in vitro, using both laboratory strains and clinical isolates of P. aeruginosa, S. aureus, and B. cepacia co-cultures. Employing a low-nutrient culture medium that fosters biofilm growth of the selected species, we quantified biofilm formation through a combination of adherent CFU counts, qPCR analysis, and confocal microscopy observations. Our findings reaffirmed the challenges faced by S. aureus in establishing growth within 1:1 mixed biofilms with P. aeruginosa when cultivated in a minimal medium. Intriguingly, at an elevated NaCl concentration of 145 mM, a symbiotic relationship emerged between S. aureus and P. aeruginosa, enabling their co-existence. Notably, this hyperosmotic environment also exerted an influence on the interplay of these two bacteria with B. cepacia. We demonstrated that elevated NaCl concentrations play a pivotal role in orchestrating the distribution of these three species within the biofilm matrix. Furthermore, our study unveiled the beneficial impact of NaCl on the biofilm growth of clinically relevant mucoid P. aeruginosa strains, as well as two strains of methicillin-sensitive and methicillin-resistant S. aureus. This underscores the crucial role of the microenvironment during the colonization and infection processes. The results suggest that hyperosmotic conditions could hold the key to unlocking a deeper understanding of the genesis and behavior of CF multi-species biofilms.}, } @article {pmid37708771, year = {2023}, author = {Sentenac, H and Loyau, A and Zoccarato, L and Jassey, VEJ and Grossart, HP and Schmeller, DS}, title = {Biofilm community composition is changing in remote mountain lakes with a relative increase in potentially toxigenic algae.}, journal = {Water research}, volume = {245}, number = {}, pages = {120547}, doi = {10.1016/j.watres.2023.120547}, pmid = {37708771}, issn = {1879-2448}, abstract = {Mountain lakes provide clear drinking water to humankind but are strongly impacted by global change. Benthic biofilms are crucial for maintaining water quality in these oligotrophic lakes, yet little is known about the effects of global change on mountain biofilm communities. By combining analyses of metabarcoding data on 16S and 18S rRNA genes with climatic and environmental data, we investigated global change effects on the composition of biofilm prokaryotic and micro-eukaryotic assemblages in a five-year monitoring program of 26 Pyrenean lakes (2016-2020). Using time-decay relationships and within-lake dissimilarity modelling, we show that the composition of both prokaryotic and micro-eukaryotic biofilm communities significantly shifted and their biodiversity declined from 2016 to 2020. In particular, analyses of temporal trends with linear mixed models indicated an increase in the richness and relative abundance of cyanobacteria, including potentially toxigenic cyanobacteria, and a concomitant decrease in diatom richness and relative abundance. While these compositional shifts may be due to several drivers of global change acting simultaneously on mountain lake biota, water pH and hardness were, from our data, the main environmental variables associated with changes for both prokaryotic and micro-eukaryotic assemblages. Water pH and hardness increased in our lakes over the study period, and are known to increase in Pyrenean lakes due to the intensification of rock weathering as a result of climate change. Given predicted climate trends and if water pH and hardness do cause some changes in benthic biofilms, those changes might be further exacerbated in the future. Such biofilm compositional shifts may induce cascading effects in mountain food webs, threatening the resilience of the entire lake ecosystem. The rise in potentially toxigenic cyanobacteria also increases intoxication risks for humans, pets, wild animals, and livestock that use mountain lakes. Therefore, our study has implications for water quality, ecosystem health, public health, as well as local economies (pastoralism, tourism), and highlights the possible impacts of global change on mountain lakes.}, } @article {pmid37708608, year = {2023}, author = {Didouh, N and Khadidja, M and Campos, C and Sampaio-Maia, B and Boumediene, MB and Araujo, R}, title = {Assessment of biofilm, enzyme production and antibiotic susceptibility of bacteria from milk pre- and post-pasteurization pipelines in Algeria.}, journal = {International journal of food microbiology}, volume = {407}, number = {}, pages = {110389}, doi = {10.1016/j.ijfoodmicro.2023.110389}, pmid = {37708608}, issn = {1879-3460}, abstract = {Bacterial biofilm is a major concern of dairy industry due to its association with milk contamination and its derived products. Algerian pasteurized milk shelf-life does not exceed one day, which may reflect the high level of contamination of this product and presence of extracellular enzymes such as lipases and proteases. This work aimed to investigate the microbial biodiversity in milk-processing surfaces of a dairy plant in Algeria. Therefore, stainless steel cylinders were placed in piping system of the dairy system before and after pasteurization of the milk, being removed after 7 days, for biofilm maturation and microorganism isolation and identification by mass spectrometry. Fifty-nine Gram-positive isolates were identified, namely Bacillus altitudinis, Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Bacillus weithenstephanensis, Enterococcus casseliflavus, Enterococcus faecium, and Staphylococcus epidermidis. In addition, twenty-four Gram-negative isolates were identified, namely Acinetobacter schindleri Enterobacter cloacae, Enterobacter xiangfangensis, Leclercia adecarboxylata, and Raoultella ornithinolytica. Bacterial isolates showed ability for production of extracellular enzymes, being 49 % capable of both proteolytic and lipolytic activities. Milk isolates were tested for the ability to form biofilms on stainless steel. The cell numbers recovered on plate count agar plates from stainless steel biofilms ranged from 3.52 to 6.92 log10 CFU/cm[2], being the maximum number detected for Enterococcus casseliflavus. Bacterial isolates showed intermediate and/or resistant profiles to multiple antibiotics. Resistance to amoxicillin, cefoxitin and/or erythromycin was commonly found among the bacterial isolates.}, } @article {pmid37707582, year = {2023}, author = {Elfarargy, RG and Sedki, M and Samhan, FA and Hassan, RYA and El-Sherbiny, IM}, title = {Surface grafting of polymeric catheters and stents to prevent biofilm formation of pathogenic bacteria.}, journal = {Journal, genetic engineering & biotechnology}, volume = {21}, number = {1}, pages = {92}, pmid = {37707582}, issn = {2090-5920}, abstract = {BACKGROUND: Tecothane (medical grade of polyurethane) is strongly involved in the fabrication of metallic and polymeric-based medical devices (e.g., catheters and stents) as they can withstand cardiac cycle-related forces without deforming or failing, and they can mimic tissue behavior. The main problem is microbial contamination and formation of pathogenic biofilms on such solid surfaces within the human body. Accordingly, our hypothesis is the coating of tecothane outer surfaces with antibacterial agents through the electro-deposition or chemical grafting of anti-biofilm agents onto the stent and catheter surfaces.

RESULTS: Tecothane is grafted with itaconic acid for cross-linking the polyethyleneimine (PEI) as the protective-active layer. Accordingly, the grafting of poly-itaconic acid onto the Tecothane was achieved by three different methods: wet-chemical approach, electro-polymerization, or by using plasma treatment. The successful modifications were verified using Fourier Transform Infrared (FTIR) spectroscopy, grafting percentage calculations, electrochemical, and microscopic monitoring of biofilm formation. The grafting efficiency of itaconic acid was over 3.2% (w/w) at 60 ℃ after 6 h of the catheter chemical modification. Bio-electrochemical signals of biofilms have been seriously reduced after chemical modification because of the inhibition of biofilm formation (for both Pseudomonas aeruginosa and Staphylococcus aureus) over a period of 9 days.

CONCLUSION: Chemical functionalization of the polyurethane materials with the antimicrobial and anti-biofilm agents led to a significant decrease in the formation of pathogenic biofilms. This promising proof-concept will open the door to explore further surface protection with potential anti-biofilm agents providing better and sustainable productions of stents and catheters biomaterials.}, } @article {pmid37704145, year = {2023}, author = {Hu, S and Johnson, DM and Jiang, M and Zhang, J and Huang, Y and Xi, Y and Xu, T}, title = {The effect of polyvinyl chloride (PVC) color on biofilm development and biofilm-heavy metal chemodynamics in the aquatic environment.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166924}, doi = {10.1016/j.scitotenv.2023.166924}, pmid = {37704145}, issn = {1879-1026}, abstract = {Plastic surfaces are colonized by microorganisms and biofilms are formed in the natural aquatic environment. As the biofilm develops, it changes the density and buoyancy of the plastic-biofilm complex, results in plastic sinking, and increases the heavy metals accumulated by biofilm's mobility and availability in aquatic ecosystems. In this experiment, biofilms were cultured on five colors of polyvinyl chloride (PVC; transparent, green, blue, red, black) in an aquatic environment to investigate the effects of plastic color on biofilm formation and development (Phase 1) and to study the effects of being sunk below the photic zone on biofilm (Phase 2). The PVC color significantly affected the biofilm formation rate but had no impact on the final biofilm biomass. After sinking the biofilm-PVC below the photic zone in Phase 2, the layer of diatoms on the biofilm surface began to disintegrate, and the biomass and Chlorophyll-a (Chla) content of the biofilm decreased, except on the red PVC. Below the photic zone, the microbial community of the biofilm changed from primarily autotrophic microbes to mostly heterotrophic microbes. Microbial diversity increased and extracellular polymeric substances (EPS) content decreased. The primary factor leading to microbial diversity and community structure changes was water depth rather than PVC color. The changes induced in the biofilm led to an increase in the concentration of all heavy metals in the biofilm, related to the increase in microbial diversity. This study provides new insights into the biofilm formation process and the effects on a biofilm when it sinks below the photic zone.}, } @article {pmid37704075, year = {2023}, author = {Brindhadevi, K and Oang, Q and Salmen, SH and Karuppusamy, I and Pugazhendhi, A}, title = {In vitro biofilm inhibition efficacy of Aerva lanata flower extract against Gram negative and Gram-positive biofilm forming bacteria and toxicity analysis using Artemia salina.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117118}, doi = {10.1016/j.envres.2023.117118}, pmid = {37704075}, issn = {1096-0953}, abstract = {A biofilm consists of Gram positive and Gram-negative bacteria enclosed in a matrix. Industrial biofouling is caused by biofilms, which can exhibit antimicrobial resistance during infections. Many biofilm studies find that nearly all biofilm communities consist of Gram positive and Gram-negative bacteria. It is therefore necessary to better understand the conserved themes in biofilm formation to develop therapeutics based on biofilm formation. Plant extracts can effectively combat pathogenic bacterial biofilms. This study evaluated the antibacterial and antibiofilm activity of Aerva lanata flower extract against Staphylococcus aureus and Pseudomonas aeruginosa. Methanol extract of dried A. lanata flower was tested against S. aureus and P. aeruginosa to determine the antibacterial activity (10, 25, 50, 75, 100 μg/mL) resulted in a maximum of 0.5-1 log reduction and 2 log reduction in comparison to the control or untreated bacterial cells respectively. A. lanata showed maximum biofilm inhibition up to 1.5-fold and 1-fold against P. aeruginosa and S. aureus. Light microscopic analysis of biofilm treated with A. lanata extract showed efficient distortion of the biofilm matrix. Further, the in vivo analysis of A. lanata in the Artemia salina brine shrimp model showed >50% survival and thus proving the efficacy of A. lanata extract in rescuing the brine shrimps against P. aeruginosa and S. aureus infection.}, } @article {pmid37703274, year = {2023}, author = {, }, title = {Editorial Note: A Differential Effect of E. coli Toxin-Antitoxin Systems on Cell Death in Liquid Media and Biofilm Formation.}, journal = {PloS one}, volume = {18}, number = {9}, pages = {e0291587}, doi = {10.1371/journal.pone.0291587}, pmid = {37703274}, issn = {1932-6203}, } @article {pmid37703270, year = {2023}, author = {Zarei, M and Elmi Anvari, S and Maktabi, S and Saris, PEJ and Yousefvand, A}, title = {Identification, proteolytic activity quantification and biofilm-forming characterization of Gram-positive, proteolytic, psychrotrophic bacteria isolated from cold raw milk.}, journal = {PloS one}, volume = {18}, number = {9}, pages = {e0290953}, doi = {10.1371/journal.pone.0290953}, pmid = {37703270}, issn = {1932-6203}, abstract = {Psychrotrophic bacteria of raw milk face the dairy industry with significant spoilage and technological problems due to their ability to produce heat-resistant enzymes and biofilms. Despite extensive information about Gram-negative psychrotrophic bacteria in milk, little is known about Gram-positive psychrotrophic bacteria in milk, and their proteolytic activity and biofilm-forming characteristics. In the present study, Gram-positive, proteolytic, psychrotrophic bacteria of cold raw milk were identified, and their proteolytic activity and biofilm-forming capacity were quantified. In total, 12 genera and 22 species were represented among the bacterial isolates, however 50% belonged to three genera, namely Staphylococcus (19.4%), Bacillus (16.7%), and Enterococcus (13.9%). Different levels of proteolytic activity were detected in the identified isolates, even among the strains belonging to the same species. In addition, proteolytic activity was significantly higher at 25°C than at 7°C for all isolates. The crystal violet staining assay in polystyrene microtitre plates revealed a high level of variation in the biofilm-forming capacity at 7°C. After 72 hours of incubation, 11.1% of the strains did not produce a biofilm, while 27.8%, 52.8%, and 8.3% produced low, moderate, and high amounts of biofilm on polystyrene, respectively. The psychrotrophic bacteria were also able to produce biofilms on the surface of stainless steel coupons in ultra-high temperature milk after 72 h of incubation at 7°C; the number of attached cells ranged from 1.34 to 5.11 log cfu/cm2. These results expand the knowledge related to the proteolytic activity and biofilm-forming capacity of Gram-positive psychrotrophic milk bacteria.}, } @article {pmid37702922, year = {2023}, author = {Pippi, B and Loreto, ES and Merkel, S and Joaquim, AR and Krummenauer, ME and Reginatto, P and Vainstein, MH and Andrade, SF and Fuentefria, AM and Santurio, JM and Zanette, RA}, title = {Pythium insidiosum: insights into biofilm formation and antibiofilm activity of antifungal drugs.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37702922}, issn = {1678-4405}, abstract = {In this study, we investigate the ability of Pythium insidiosum to form biofilms across various substrates and the antibiofilm efficacy of 8-hydroxyquinoline derivatives (8-HQs). Biofilms of P. insidiosum were cultured on polystyrene plates, contact lenses, and horsehair. We provide the first evidence of P. insidiosum's biofilm-forming capability, thus considerably expanding our understanding of its transmission and pathogenesis. Our results demonstrate that 8-HQs effectively inhibit biofilm formation and eradicate pre-existing biofilms, underscoring their potential as a novel treatment strategy for pythiosis, a disease currently lacking a gold-standard treatment. This finding has particular relevance for ocular pythiosis associated with contact lens usage and potential infection sources in animals. Our results contribute to the scientific knowledge base and directly impact innovative therapeutic interventions' development.}, } @article {pmid37702709, year = {2023}, author = {Ruhal, R and Ghosh, M and Kumar, V and Jain, D}, title = {Mutation of putative glycosyl transferases PslC and PslI confers susceptibility to antibiotics and leads to drastic reduction in biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {9}, pages = {}, doi = {10.1099/mic.0.001392}, pmid = {37702709}, issn = {1465-2080}, abstract = {Pseudomonas aeruginosa is an opportunistic, multidrug-resistant pathogen capable of adapting to numerous environmental conditions and causing fatal infections in immunocompromised patients. The predominant lifestyle of P. aeruginosa is in the form of biofilms, which are structured communities of bacteria encapsulated in a matrix containing exopolysaccharides, extracellular DNA (eDNA) and proteins. The matrix is impervious to antibiotics, rendering the bacteria tolerant to antimicrobials. P. aeruginosa also produces a plethora of virulence factors such as pyocyanin, rhamnolipids and lipopolysaccharides among others. In this study we present the molecular characterization of pslC and pslI genes, of the exopolysaccharide operon, that code for putative glycosyltransferases. PslC is a 303 amino acid containing putative GT2 glycosyltrasferase, whereas PslI is a 367 aa long protein, possibly functioning as a GT4 glycosyltransferase. Mutation in either of these two genes results in a significant reduction in biofilm biomass with concomitant decline in c-di-GMP levels in the bacterial cells. Moreover, mutation in pslC and pslI dramatically increased susceptibility of P. aeruginosa to tobramycin, colistin and ciprofloxacin. Additionally, these mutations also resulted in an increase in rhamnolipids and pyocyanin formation. We demonstrate that elevated rhamnolipids promote a swarming phenotype in the mutant strains. Together these results highlight the importance of PslC and PslI in the biogenesis of biofilms and their potential as targets for increased antibiotic susceptibility and biofilm inhibition.}, } @article {pmid37701779, year = {2023}, author = {Liu, S and Zhang, T and Li, Z and Wang, Y and Liu, L and Song, Z}, title = {Antibacterial mechanism of areca nut essential oils against Streptococcus mutans by targeting the biofilm and the cell membrane.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1140689}, doi = {10.3389/fcimb.2023.1140689}, pmid = {37701779}, issn = {2235-2988}, abstract = {INTRODUCTION: Dental caries is one of the most common and costly biofilm-dependent oral diseases in the world. Streptococcus mutans is the major cariogenic pathogen of dental caries. S. mutans synthesizes extracellular polysaccharides by autologous glucosyltransferases, which then promotes bacterial adhesion and cariogenic biofilm formation. The S. mutans biofilm is the principal target for caries treatment. This study was designed to explore the antibacterial activity and mechanisms of areca nut essential oil (ANEO) against S. mutans.

METHODS: The ANEOs were separated by negative pressure hydro-distillation. The Kirby-Bauer method and broth microdilution method were carried out to evaluate the antibacterial activity of different ANEOs. The antibacterial mechanism was revealed by crystal violet staining, XTT reduction, microbial adhesion to hydrocarbon test, extracellular polysaccharide production assay, glucosyltransferase activity assay, lactate dehydrogenase leaking, propidium iodide staining and scanning electron microscopy (SEM). The cytotoxicity of ANEOs was determine by MTT assay.

RESULTS: The ANEOs separated at different temperatures exhibited different levels of antibacterial activity against S. mutans, and the ANEO separated at 70°C showed the most prominent bacteriostatic activity. Anti-biofilm experiments showed that the ANEOs attenuated the adhesion ability of S. mutans by decreasing the surface hydrophobicity of the bacteria, prevented S. mutans biofilm formation by inhibiting glucosyltransferase activity, reducing extracellular polysaccharide synthesis, and reducing the total biofilm biomass and activity. SEM further demonstrated the destructive effects of the ANEOs on the S. mutans biofilm. Cell membrane-related experiments indicated that the ANEOs destroyed the integrity of the cell membrane, resulting in the leakage of lactic dehydrogenase and nucleic acids. SEM imaging of S. mutans cell showed the disruption of the cellular morphology by the ANEOs. The cytotoxicity assay suggested that ANEO was non-toxic towards normal oral epithelial cells.

DISCUSSION: This study displayed that ANEOs exerted antibacterial activity against S. mutans primarily by affecting the biofilm and disrupting the integrity of the cell membrane. ANEOs has the potential to be developed as an antibacterial agent for preventing dental caries. Additionally, a new method for the separation of essential oil components is presented.}, } @article {pmid37701006, year = {2023}, author = {Kumar, D and Mehrishi, P and Faujdar, SS and Chaudhary, BL and Panwar, S}, title = {Status of Biofilm Production and Vancomycin Resistance in Enterococcus in the Rural Population of Mathura, India.}, journal = {Cureus}, volume = {15}, number = {8}, pages = {e43351}, pmid = {37701006}, issn = {2168-8184}, abstract = {Introduction Hospital-acquired or nosocomial infections caused by the rapidly emerging bacteria vancomycin-resistant enterococci can be dangerous and even fatal. Therefore, this study aimed to investigate the presence of enterococci in various clinical specimens along with their vancomycin resistance status and biofilm-producing capabilities. Methods A total of 164 Enterococcus species were isolated and further included in this study. Isolation and identification were done by the standard bacteriological procedure, antibiotic susceptibility testingwas done by clinical laboratory standard guidelines, and biofilm production test was done by microtiter plate methods. Results Among the total of 164 isolates, Enterococcus faecalis constituted 60.97% and Enterococcus faecium constituted 39.02%. Maximum isolates were from urine samples. The prevalence of vancomycin-resistant Enterococcus was 6.70%, and 18.29% of Enterococcus isolates were biofilm producers. The sensitivity among the biofilm producers was maximum for linezolid (87.33%), followed by teicoplanin (86.43%) and vancomycin (79.64%). Conclusion High prevalence of enterococci was found in urine samples and biofilm producers Enterococcus isolates were more antibiotic-resistant than non-biofilm producers.}, } @article {pmid37700508, year = {2023}, author = {Szymankiewicz, M and Jarzynka, S and Koryszewska-Bagińska, A and Nowikiewicz, T}, title = {The Impact of Nasal Staphylococcus aureus Carriage on Surgical-Site Infections after Immediate Breast Reconstruction: Risk Factors and Biofilm Formation Potential.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {29}, number = {}, pages = {e940898}, doi = {10.12659/MSM.940898}, pmid = {37700508}, issn = {1643-3750}, abstract = {BACKGROUND Despite the benefits of implant-based breast reconstruction in patients with breast cancer, the procedure can be complicated by surgical site infections (SSI). This study aimed to evaluate the association between nasal carriage of Staphylococcus aureus strains and the incidence of SSI among patients who underwent reconstructive procedures. We also assessed the ability of colonizing S. aureus strains to form biofilm. MATERIAL AND METHODS Medical data from 124 patients with 132 post-mastectomy breast reconstructions performed at the Oncology Center in Bydgoszcz, Poland, between June 2020 and August 2021 were analyzed. A 90-day incidence of SSI was found in 7/132 reconstructions (5.3%). The study group included 132 reconstructions, and was divided into those with infection (n=7) and without infection (n=125). Between-group differences were assessed using the t test for continuous variables and chi-square test for categorical variables. Biofilm formation among 32 S. aureus strains was determined by using quantitative and qualitative assays. RESULTS There were no significant differences in relation to the patients' S. aureus colonization status. Infections occurred both in patients colonized and not colonized with S. aureus. S. aureus nasal carriage did not affect the rate of SSI at 90 days after surgery. About 97.0% of the strains had a strong capacity for biofilm formation. CONCLUSIONS There was no association between nasal carriage of strains of S. aureus and the incidence of SSI. However, further investigations on a larger group of patients and longer observation time are needed to investigate this potential risk factor in detail.}, } @article {pmid37699554, year = {2023}, author = {West, KHJ and Ma, SV and Pensinger, DA and Tucholski, T and Tiambeng, TN and Eisenbraun, EL and Yehuda, A and Hayouka, Z and Ge, Y and Sauer, JD and Blackwell, HE}, title = {Characterization of an Autoinducing Peptide Signal Reveals Highly Efficacious Synthetic Inhibitors and Activators of Quorum Sensing and Biofilm Formation in Listeria monocytogenes.}, journal = {Biochemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.biochem.3c00373}, pmid = {37699554}, issn = {1520-4995}, abstract = {Bacteria can use chemical signals to assess their local population density in a process called quorum sensing (QS). Many of these bacteria are common pathogens, including Gram-positive bacteria that utilize agr QS systems regulated by macrocyclic autoinducing peptide (AIP) signals. Listeria monocytogenes, an important foodborne pathogen, uses an agr system to regulate a variety of virulence factors and biofilm formation, yet little is known about the specific roles of agr in Listeria infection and its persistence in various environments. Herein, we report synthetic peptide tools that will enable the study of QS in Listeria. We identified a 6-mer AIP signal in L. monocytogenes supernatants and selected it as a scaffold around which a collection of non-native AIP mimics was designed and synthesized. These peptides were evaluated in cell-based agr reporter assays to generate structure-activity relationships for AIP-based agonism and antagonism in L. monocytogenes. We discovered synthetic agonists with increased potency relative to native AIP and a synthetic antagonist capable of reducing agr activity to basal levels. Notably, the latter peptide was able to reduce biofilm formation by over 90%, a first for a synthetic QS modulator in wild-type L. monocytogenes. The lead agr agonist and antagonist in L. monocytogenes were also capable of antagonizing agr signaling in the related pathogen Staphylococcus aureus, further extending their utility and suggesting different mechanisms of agr activation in these two pathogens. This study represents an important first step in the application of chemical methods to modulate QS and concomitant virulence outcomes in L. monocytogenes.}, } @article {pmid37699484, year = {2023}, author = {Song, Z and Liao, R and Su, X and Zhang, X and Zhao, Z and Sun, F}, title = {Development of a novel three-dimensional biofilm-electrode system (3D-BES) loaded with Fe-modified biochars for enhanced pollutants removal in landfill leachate.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166980}, doi = {10.1016/j.scitotenv.2023.166980}, pmid = {37699484}, issn = {1879-1026}, abstract = {Different mass ratio iron (Fe)-loaded biochars (FeBCs) were prepared from food waste and used in the three-dimensional biofilm-electrode systems (3D-BES) as particular electrodes for landfill leachate treatment. Compared to the unmodified biochar (BC), specific surface area of Fe-loaded biochars (FeBC-3 with a Fe: biochar of 0.2:1) increased from 63.01 m[2]/g to 184.14 m[2]/g, and pore capacity increased from 0.038 cm[3]/g to 0.111 cm[3]/g. FeBCs provided more oxygen-containing functional groups and exhibited excellent redox properties. Installed with FeBC-3 as particular electrode, both NH4[+]-N and chemical oxygen demand COD removals in 3D-BESs were well fitted with the pseudo-first-order model, with the maximum removal efficiencies of 98.6 % and 95.5 %, respectively. The batch adsorption kinetics experiments confirmed that the maximum NH4[+]-N (7.5 mg/g) and COD (21.8 mg/g) adsorption capacities were associated closely with the FeBC-3 biochar. In contrast to the 3D-BES with the unmodified biochar, Fe-loaded biochars significantly increased the abundance of microorganisms being capable of removing organics and ammonia. Meanwhile, the increased content of dehydrogenase (DHA) and electron transport system activity (ETSA) evidenced that FeBCs could enhance microbial internal activities and regulate electron transfer process among functional microorganisms. Consequently, it is concluded that Fe-loaded biochar to 3D-BES is effective in enhancing pollutant removals in landfill leachate and provided a reliable and effective strategy for refractory wastewater treatment.}, } @article {pmid37700331, year = {2023}, author = {Shebl, RI and Elkhatib, WF and Badawy, MSEM}, title = {Modulating the transcriptomic profile of multidrug-resistant Klebsiella pneumoniae biofilm formation by antibiotics in combination with zinc sulfate.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {22}, number = {1}, pages = {84}, pmid = {37700331}, issn = {1476-0711}, abstract = {BACKGROUND: Klebsiella pneumoniae is a significant healthcare-associated pathogen. We investigated the antimicrobial interaction pattern between zinc sulfate and antibiotics against K. pneumoniae biofilm on the phenotypic and genotypic levels.

METHODS: Determining the minimum biofilm inhibitory concentrations and the transcriptomic profile of K. pneumoniae biofilm formation genes post-treatment were carried out to evaluate the effect on the phenotypic and genotypic levels, respectively.

RESULTS: Zinc enhanced the antibiofilm potentials of cephalosporins, aminoglycosides, and ertapenem, whereas it antagonizes the effectiveness of fluoroquinolones and meropenem on the phenotypic level. On the molecular level, zinc enhanced the anti-biofilm efficacies of cephalosporins (cefotaxime, ceftriaxone, ceftazidime, cefpirome, and cefepime) via down-regulating the expression of biofilm-related genes by 18-, 38-, 5-, 77- and 2-folds, respectively. Zinc in combination with aminoglycosides (kanamycin, gentamicin, and amikacin) reduced the expression of biofilm-related genes by 40-, 2602- and 20-folds, respectively, and by 2-folds in combination with ertapenem. However, a reduction in the down-regulatory potentials of fluoroquinolones was recorded following combination with zinc by 2-, 2-, 15- and 14-folds, respectively, and an up-regulation in the expression levels of the tested genes by 2-folds in the case of zinc/meropenem combination.

CONCLUSIONS: Results revealed variable interaction patterns between different antibiotics in combination with zinc. Current findings also shed light on the antibiofilm potentials of zinc/antibiotics combinations especially when combining zinc with fluoroquinolones or meropenem to avoid their antagonistic effects.}, } @article {pmid37699825, year = {2023}, author = {Tao, H and Yu, D and Yang, L and Chen, YY and Zhou, LQ and Luo, YX}, title = {[Influence of Polystyrene Microplastics on the Formation and Structural Change of Pseudomonas aeruginosa Biofilm].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {44}, number = {9}, pages = {5071-5079}, doi = {10.13227/j.hjkx.202209057}, pmid = {37699825}, issn = {0250-3301}, abstract = {Microplastic pollution in the water environment is becoming increasingly serious, impacting the growth and development of aquatic organisms. There are limited studies on the mechanisms of microplastic effects on biofilm formation. Therefore, in this study, the effects of polystyrene microplastics (PS-MPs) were investigated on the biofilm formation and development of Pseudomonas aeruginosa. Different concentrations and particle sizes of PS-MPs were selected for exposure tests to explore the effects on biofilm biomass, oxidative stress levels, biofilm structure, and population sensing system. The results showed that PS-MPs induced severe oxidative stress and inhibited biofilm formation and development, and the smaller the particle size, the stronger the inhibitory effect was. The inhibition effect was 0.1 μm>0.5 μm≈1 μm>5 μm. PS-MPs caused severe physical damage through contact with bacteria. The thickness of the biofilm was significantly reduced, damaging the structural stability. The bacteria in the biofilm secreted extracellular polymers to resist the stress of PS-MPs. Meanwhile, PS-MPs interfered with the QS system of P. aeruginosa; down-regulated the expression levels of key genes lasI, lasR, rhlI, and rhlR; inhibited the synthesis and secretion of signal molecules and related virulence factors; and ultimately affected the formation and structural stability of biofilms.}, } @article {pmid37699792, year = {2023}, author = {Ilham, D and Souad, L and Asmae, LH and Kawtar, N and Mohammed, T and Nabila, S}, title = {Prevalence, antibiotic resistance profile, MBLs encoding genes, and biofilm formation among clinical carbapenem-resistant Enterobacterales isolated from patients in Mohammed VI University Hospital Centre, Morocco.}, journal = {Letters in applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/lambio/ovad107}, pmid = {37699792}, issn = {1472-765X}, abstract = {Enterobacterales are frequently a major cause of human infections. The emergence of carbapenem resistance as well as the biofilm formation complicate their management. In this regard, this study aimed to investigate the prevalence, antibiogram, carbapenemase genes and biofilm production among Enterobacterales. For this purpose, 18172 clinical specimens from hospitalized patients in Mohammed VI University Hospital were collected over two years (2018-2019). The bacteriological investigation was performed to isolate Enterobacterales. Subsequently, BD-Phoenix and MALDI-TOF-MS were used for bacterial identification. The production of ESBLs and carbapenemases was assessed using phenotypic tests and PCR. The biofilm formation was eventually carried out. Out of 195 carbapenem-resistant Enterobacterales strains, 190 were carbapenemase producers, and 74 Enterobacterales produced MBLs. The PCR results revealed that blaNDM was the most common carbapenemase gene, present in 62 cases, followed by the co-existence of blaNDM and blaOXA-48 in 12 cases. K. pneumoniae was the most frequently identified species among the 74 NDM isolates and the XDR resistance phenotype was the most prevalent with 58.10%. Additionally, all 74 NDM-positive Enterobacterales were able to form biofilms, with 82.4% being strong producers. This study highlights the need for rapid detection of carbapenemase and biofilm production in our hospital to manage this health concern.}, } @article {pmid37699187, year = {2023}, author = {Shibasaki, PAN and Cavalli, V and Oliveira, MC and Barbosa, JP and Boriollo, MFG and Martins, LRM}, title = {Influence of Surface Treatment on the Physical Properties and Biofilm Formation of Zirconia- Reinforced Lithium Silicate Ceramics: In Vitro Trial.}, journal = {The International journal of prosthodontics}, volume = {36}, number = {4}, pages = {460-468}, doi = {10.11607/ijp.7192}, pmid = {37699187}, issn = {1942-4426}, abstract = {PURPOSE: To evaluate the performance of fully crystallized zirconia-reinforced lithium silicate (Celtra Duo, ZLS-CD), partially crystallized zirconia-reinforced lithium silicate (Vita Suprinity, ZLS-VS), and partially sintered lithium disilicate-based (IPS e.max CAD, LD) glass-ceramics submitted to polishing, glazing, or no surface treatment after aging.

MATERIAL AND METHODS: Samples of each glass-ceramic material were subjected to polishing with rubber cups (POL), glazing (GL), or no treatment (control: unpolished) and afterward aged with 18,000 thermal cycles (5.C to 55.C). The average roughness, 2D and 3D morphology, contact angle, multispecies biofilm formation (Streptococcus mutans and Candida albicans), and mechanical strength were evaluated with atomic force microscopy (AFM, n = 5), sessile-drop goniometry (n = 5), spectrophotometry (n = 5), and the flexural strength test (n = 10), respectively. Data were analyzed using two-way ANOVA and Tukey test (α = 5%).

RESULTS: POL produced lower surface roughness than GL, and ZLS-CD presented higher roughness than LD (P < .05). Surfaces without polishing displayed higher roughness than the POL group (P < .001), greater contact angle (P < .001), and significant morphologic changes, regardless of the glass-ceramic material. Irrespective of the treatment, the contact angle was higher in the ZLS-CD group, and regardless of the material, there was higher biofilm formation and lower flexural strength of the unpolished compared to the POL or GL ceramics.

CONCLUSIONS: POL promoted lower roughness and minor morphologic surface alterations, but biofilm formation and flexural strength were similar to the GL group. In general, ZLS-CD and ZLS-VS showed more similar behavior than LD, which makes ZLS glass-ceramic a good option for indirect restorations.}, } @article {pmid37698054, year = {2023}, author = {Andrade, ARC and Rezende, MDS and Portela, FVM and Pereira, LMG and Nascimento da Silva, B and Lima-Neto, RG and Rocha, MFG and Sidrim, JJC and Castelo-Branco, DSCM and Cordeiro, RA}, title = {β-Estradiol and progesterone enhance biofilm development and persister cell formation in monospecies and microcosms biofilms derived from vulvovaginal candidiasis.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-11}, doi = {10.1080/08927014.2023.2256674}, pmid = {37698054}, issn = {1029-2454}, abstract = {The present study aimed to: (1) evaluate the influence of the steroid hormones (SH) on biofilm development; (2) investigate the formation of persister cells (PC) in biofilms; and (3) investigate the influence of SH on PC formation. Biofilms were derived from vulvovaginal candidiasis (VVC) samples and evaluated by three models: microcosm biofilms grown in Vaginal Fluid Simulator Medium (MiB-VFSM); monospecies biofilms grown in VFSM (MoB-VFSM) and RPMI media (MoB-RPMI). SH altered cell counting and biomass of biofilms grown in VSFM; MoB-RPMI were negatively affected by SH. SH stimulated the formation of PC in MiB-VFSM but not MoB-VFSM; MoB-RPMI showed a lower number of PC in the presence of SH. The results showed that SH altered the dynamics of biofilm formation and development, depending on the study model. The data suggest the influence of hormones on the physiology of Candida biofilms and reinforce the importance of PC in the pathogenesis of VVC.}, } @article {pmid37696222, year = {2023}, author = {Thatikayala, D and Min, B}, title = {Enhancing electrochemical nitrite sensing with a novel nanocomposite of activated carbon/carbon cloth derived from microbial biofilm.}, journal = {Biosensors & bioelectronics}, volume = {241}, number = {}, pages = {115659}, doi = {10.1016/j.bios.2023.115659}, pmid = {37696222}, issn = {1873-4235}, abstract = {A novel approach was employed to fabricate a biofilm-derived activated carbon (BioAc) electrode on a carbon cloth (Cc) substrate for electrochemical nitrite sensing in water samples. The biofilm/Cc electrode was developed using a bioelectrochemical reactor, featuring a three-electrode system with nutrient media and microbial sources. The resultant biofilm electrode was activated at 450 °C for 2 h to eliminate impurities and enhance porosity. Morphological analysis of the BioAc/Cc electrode revealed a surface characterized by a compact film composed of numerous carbon nanoparticles. X-ray diffraction (XRD) analysis exhibited broad, highly crystalline peaks, enhancing both the electrode surface area and conductivity. Amperometry tests on the modified BioAc/Cc electrodes demonstrated a detection limit of 0.015 μM, a sensitivity of 1946.54 μA mM[-1] cm[-2], and a linear range spanning 0.35-478.21 μM at neutral pH conditions. Moreover, the electrodes demonstrated good stability with a RSD of 2.25% after 60 days and high reproducibility with an RSD of 1.64%. Real-time results showed 99.2 and 100.1% recovery for tap water and drinking water, respectively, highlighting the potential for commercialization in the future. These findings suggest that the BioAc/Cc electrode holds substantial potential for precise nitrite detection in environmental and wastewater applications.}, } @article {pmid37696079, year = {2023}, author = {Sushmitha, TJ and Rajeev, M and Murthy, PS and Rao, TS and Pandian, SK}, title = {Planktonic and early-stage biofilm microbiota respond contrastingly to thermal discharge-created seawater warming.}, journal = {Ecotoxicology and environmental safety}, volume = {264}, number = {}, pages = {115433}, doi = {10.1016/j.ecoenv.2023.115433}, pmid = {37696079}, issn = {1090-2414}, abstract = {Thermal-discharges from power plants highly disturb the biological communities of the receiving water body and understanding their influence is critical, given the relevance to global warming. We employed 16 S rRNA gene sequencing to examine the response of two dominant marine bacterial lifestyles (planktonic and biofilm) against elevated seawater temperature (+5 ℃). Obtained results demonstrated that warming prompted high heterogeneity in diversity and composition of planktonic and biofilm microbiota, albeit both communities responded contrastingly. Alpha diversity revealed that temperature exhibited positive effect on biofilm microbiota and negative effect on planktonic microbiota. The community composition of planktonic microbiota shifted significantly in warming area, with decreased abundances of Bacteroidetes, Cyanobacteria, and Actinobacteria. Contrastingly, these bacterial groups exhibited opposite trend in biofilm microbiota. Co-occurrence networks of biofilm microbiota displayed higher node diversity and co-presence in warming area. The study concludes that with increasing ocean warming, marine biofilms and biofouling management strategies will be more challenging.}, } @article {pmid37695853, year = {2023}, author = {Dye, KJ and Salar, S and Allen, U and Smith, W and Yang, Z}, title = {Myxococcus xanthus PilB interacts with c-di-GMP and modulates motility and biofilm formation.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0022123}, doi = {10.1128/jb.00221-23}, pmid = {37695853}, issn = {1098-5530}, abstract = {The regulation of biofilm and motile states as alternate bacterial lifestyles has been studied extensively in flagellated bacteria, where the second messenger cyclic-di-GMP (cdG) plays a crucial role. However, much less is known about the mechanisms of such regulation in motile bacteria without flagella. The bacterial type IV pilus (T4P) serves as a motility apparatus that enables Myxococcus xanthus to move on solid surfaces. PilB, the T4P assembly ATPase, is, therefore, required for T4P-dependent motility in M. xanthus. Interestingly, T4P is also involved in the regulation of exopolysaccharide as the biofilm matrix material in this bacterium. A newly discovered cdG-binding domain, MshEN, is conserved in the N-terminus of PilB (PilBN) in M. xanthus and other bacteria. This suggests that cdG may bind to PilB to control the respective outputs that regulate biofilm development and T4P-powered motility. In this study, we aimed to validate M. xanthus PilB as a cdG effector protein. We performed a systematic mutational analysis of its cdG-binding domain to investigate its relationship with motility, piliation, and biofilm formation. Excluding those resulting in low levels of PilB protein, all other substitution mutations in PilBN resulted in pilB mutants with distinct and differential phenotypes in piliation and biofilm levels in M. xanthus. This suggests that the PilBN domain plays dual roles in modulating motility and biofilm levels, and these two functions of PilB can be dependent on and independent of each other in M. xanthus. IMPORTANCE The regulation of motility and biofilm by cyclic-di-GMP in flagellated bacteria has been extensively investigated. However, our knowledge regarding this regulation in motile bacteria without flagella remains limited. Here, we aimed to address this gap by investigating a non-flagellated bacterium with motility powered by bacterial type-IV pilus (T4P). Previous studies hinted at the possibility of Myxococcus xanthus PilB, the T4P assembly ATPase, serving as a cyclic-di-GMP effector involved in regulating both motility and biofilm. Our findings strongly support the hypothesis that PilB directly interacts with cyclic-di-GMP to act as a potential switch to promote biofilm formation or T4P-dependent motility. These results shed light on the bifurcation of PilB functions and its pivotal role in coordinating biofilm formation and T4P-mediated motility.}, } @article {pmid37695682, year = {2023}, author = {Tong, CY and Lim, SL and Chua, MX and Derek, CJC}, title = {Uncovering the role of algal organic matter biocoating on Navicula incerta cell deposition and biofilm formation.}, journal = {Bioengineered}, volume = {14}, number = {1}, pages = {2252213}, doi = {10.1080/21655979.2023.2252213}, pmid = {37695682}, issn = {2165-5987}, abstract = {Spontaneous natural biofilm concentrates microalgal biomass on solid supports. However, the biofilm is frequently susceptible to exfoliation upon nutrient deficiency, particularly found in aged biofilm. Therefore, this study highlights a novel biofilm cultivation technique by pre-depositing the algal organic matters from marine diatom, Navicula incerta onto microporous polyvinylidene fluoride membrane to further strengthen the biofilm developed. Due to the improvement in membrane surface roughness and hydrophobicity, cells adhered most abundantly to soluble extrapolymeric substances-coated (sEPS) (76×10[6]±16×10[6] cells m[-2]), followed by bounded EPS-coated (57.67×10[6]±0.33×10[6] cells m[-2]), internally organic matter (IOM)-coated (39.00×10[6]±5.19×10[6] cells m[-2]), and pristine control the least (6.22×10[6]±0.77×10[6] cells m[-2]) at 24[th] h. Surprisingly, only bEPS-coated membrane demonstrated an increase in cell adhesion toward the end of the experiment at 72 h. The application of the bio-coating has successfully increased the rate of cell attachment by at least 45.3% upon inoculation and achieved as high as 89.9% faster attachment at 72 hours compared to the pristine control group. Soluble polysaccharides and proteins might be carried along by the cells adhering onto membranes hence resulting in a built up of EPS hydrophobicity (>70% in average on bio-coated membranes) over time as compared with pristine (control) that only recorded an average of approximately 50% hydrophobicity. Interestingly, cells grown on bio-coated membranes accumulated more internally bounded polysaccharides, though bio-coating had no discernible impact on the production of both externally and internally bounded protein. The collective findings of this study reveal the physiological alterations of microalgal biofilms cultured on bio-coated membranes.}, } @article {pmid37695459, year = {2023}, author = {Ankudze, B and Neglo, D and Nsiah, F}, title = {Green synthesis of silver nanoparticles from discarded shells of velvet tamarind (Dialium cochinchinense) and their antimicrobial synergistic potentials and biofilm inhibition properties.}, journal = {Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine}, volume = {}, number = {}, pages = {}, pmid = {37695459}, issn = {1572-8773}, abstract = {In the field of nanomedicine, biogenic metal nanoparticles are commonly synthesized using edible plant products as bio-reducing or stabilizing agents. In this study, discarded shell of velvet tamarind fruit is explored as a potent reducing agent for biogenic synthesis of silver nanoparticles (VeV-AgNPs). Silver nanoparticles were formed in minutes under sunlight exposure, which was considerably fast compared to under ambient conditions. The optical, structural and morphological studies revealed that the nanoparticle colloidal solution consisted of particles with quasi-spherical and rodlike morphologies. To investigate antimicrobial properties, eight microorganisms were exposed to the VeV-AgNPs. The results indicated that VeV-AgNPs had enhanced antimicrobial activity, with a recorded minimum inhibitory concentration (MIC) of 3.9 µg/mL against E. coli. Further studies were conducted to examine the biofilm inhibition properties and synergistic effect of the VeV-AgNPs. The findings showed a biofilm inhibition potential of around 98% against E. coli, and the particles were also found to increase the efficacy of standard antimicrobial agents. The combinatory effect with standard antifungal and antibacterial agents ranged from synergistic to antagonistic effects against the tested microorganisms. These results suggest that silver nanoparticles produced from discarded shells of velvet tamarind are potent and could be used as a potential drug candidate to combat antimicrobial resistance.}, } @article {pmid37694162, year = {2023}, author = {Dergham, Y and Le Coq, D and Bridier, A and Sanchez-Vizuete, P and Jbara, H and Deschamps, J and Hamze, K and Yoshida, KI and Noirot-Gros, MF and Briandet, R}, title = {Bacillus subtilis NDmed, a model strain for biofilm genetic studies.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100152}, doi = {10.1016/j.bioflm.2023.100152}, pmid = {37694162}, issn = {2590-2075}, abstract = {The Bacillus subtilis strain NDmed was isolated from an endoscope washer-disinfector in a medical environment. NDmed can form complex macrocolonies with highly wrinkled architectural structures on solid medium. In static liquid culture, it produces thick pellicles at the interface with air as well as remarkable highly protruding ''beanstalk-like'' submerged biofilm structures at the solid surface. Since these mucoid submerged structures are hyper-resistant to biocides, NDmed has the ability to protect pathogens embedded in mixed-species biofilms by sheltering them from the action of these agents. Additionally, this non-domesticated and highly biofilm forming strain has the propensity of being genetically manipulated. Due to all these properties, the NDmed strain becomes a valuable model for the study of B. subtilis biofilms. This review focuses on several studies performed with NDmed that have highlighted the sophisticated genetic dynamics at play during B. subtilis biofilm formation. Further studies in project using modern molecular tools of advanced technologies with this strain, will allow to deepen our knowledge on the emerging properties of multicellular bacterial life.}, } @article {pmid37692920, year = {2023}, author = {Sameni, F and Hajikhani, B and Hashemi, A and Owlia, P and Niakan, M and Dadashi, M}, title = {The Relationship between the Biofilm Genes and Antibiotic Resistance in Stenotrophomonas maltophilia.}, journal = {International journal of microbiology}, volume = {2023}, number = {}, pages = {8873948}, doi = {10.1155/2023/8873948}, pmid = {37692920}, issn = {1687-918X}, abstract = {OBJECTIVES: Today, Stenotrophomonas maltophilia (S. maltophilia) is a major opportunistic pathogen among hospitalized or immunocompromised patients. Antibiotic-resistant clinical isolates are increasing in several parts of the world. Various antibiotic-resistance and biofilm-forming genes are identified in this bacterium. Its capacity to form biofilms is an important virulence factor that may impact antibiotic-resistance patterns. In the current study, we evaluated the biofilm-formation capacity, antibiotic-resistance profile, and prevalence of biofilm-forming genes as well as antibiotic resistance genes among S. maltophilia isolates.

MATERIALS AND METHODS: In this cross-sectional study, 94 clinical S. maltophilia isolates were recovered from four tertiary-care hospitals in Iran between 2021 and 2022. The presence of the selected antibiotic-resistance genes and biofilm-forming genes was examined by polymerase chain reaction (PCR). The ability of biofilm formation was examined by microtiter plate assay. The Kirby-Bauer disc diffusion method was used to evaluate the trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and minocycline resistance.

RESULTS: S. maltophilia is mainly isolated from bloodstream infections. Notably, 98.93% of isolates were biofilm producers, of which 19.35%, 60.22%, and 20.43% produced strong, moderate, and weak biofilm, respectively. The frequency of biofilm genes was 100%, 97.88%, 96.80%, and 75.53% for spgM, rmlA, smf-1, and rpfF, respectively. Isolates with the genotype of smf-1+/rmlA+/spgM+/rpfF+ were mostly strong biofilm producers. Among the antibiotic-resistance genes, the Smqnr, L1, and sul1 had the highest prevalence (76.59%, 72.34%, and 64.89), respectively. Antimicrobial susceptibility evaluation showed 1.06%, 3.19%, and 6.3% resistance to minocycline, TMP-SMX, and levofloxacin.

CONCLUSION: The results of the current study demonstrated that S. maltophilia isolates differ in biofilm-forming ability. Moreover, smf-1, rmlA, and spgM genes were presented in all strong biofilm producers. Although the overall resistance rate to the evaluated antibiotics was high, there was no statistically significant relation between antibiotic resistance and the type of biofilm.}, } @article {pmid37692466, year = {2023}, author = {Usman, M and Marcus, A and Fatima, A and Aslam, B and Zaid, M and Khattak, M and Bashir, S and Masood, S and Rafaque, Z and Dasti, JI}, title = {Synergistic Effects of Gentamicin, Cefepime, and Ciprofloxacin on Biofilm of Pseudomonas aeruginosa.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {5887-5898}, doi = {10.2147/IDR.S426111}, pmid = {37692466}, issn = {1178-6973}, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen involved in number of hospital-acquired infections such as catheter-associated urinary tract infections, bacteremia, septicemia, skin infections, and ventilator-associated pneumoniae. Biofilm formation is an important trait implicated in chronic infections, such as cystic fibrosis and chronic pulmonary obstruction. We evaluated effects of gentamicin, cefepime, and ciprofloxacin on biofilm of P. aeruginosa.

MATERIALS AND METHODS: A total of 266 isolates were collected from the Armed Forces Institute of Pathology (AFIP). Antibiotic susceptibility was assessed by double disk synergy testing. ESBL and carbapenemase detection was performed by phenotypic testing. Molecular screening of the genes was done by PCR. Micro-dilution broth method was used to determine minimum inhibitory concentrations of antibiotics. Biofilm formation was done by micro-titer plate assay.

RESULTS: Overall, 20% of the P. aeruginosa isolates were extensively drug-resistant (XDR-PA), and 25% were multi-drug-resistant (MDR-PA). Likewise, 43% of the isolates were ESBL producers, and carbapenemase production was detected in 40% of the isolates. Molecular analysis confirmed occurrence of different resistant factors in ESBL-positive isolates; 67% carried blaTEM, 62% blaCTXM-15, 41% blaSHV, 34% blaCTXM-14, and 33% blaOXA-1. In addition, 68% of the carbapenem-resistant isolates were positive for blaNDM-1, 25% for blaOXA-48, and 22% for blaKPC-2. Biofilm formation was assessed for 234 isolates, out of which 28% were strong biofilm formers. Moderate and weak biofilm formers constituted 46% and 23%, respectively. Overall, ciprofloxacin, levofloxacin, and cefepime showed inhibitory effects on P. aeruginosa biofilms. Antibiotics in combination showed strong synergistic effects (ciprofloxacin and cefepime), while gentamicin and cefepime resulted in complete eradication of P. aeruginosa biofilm.

CONCLUSION: We confirm strong synergistic effects of gentamicin and cefepime that completely eradicated P. aeruginosa biofilm. We further confirm inhibitory effects of ciprofloxacin, levofloxacin, and cefepime on P. aeruginosa biofilms. Hence, combination therapy can be more effective against biofilm-associated infections.}, } @article {pmid37690561, year = {2023}, author = {Haddiuzaman, M and Mirza, N and Brown, SP and Ladner, DA and Salehi, M}, title = {Lead (Pb) deposition onto new and biofilm-laden potable water pipes.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140135}, doi = {10.1016/j.chemosphere.2023.140135}, pmid = {37690561}, issn = {1879-1298}, abstract = {Heavy metals' interactions with plumbing materials are complicated due to the differential formation of biofilms within pipes that can modulate, transform, and/or sequester heavy metals. This research aims to elucidate the mechanistic role of biofilm presence on Lead (Pb) accumulation onto crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper potable water pipes. For this purpose, biofilms were grown on new pipes for three months. Five-day Pb exposure experiments were conducted to examine the kinetics of Pb accumulation onto the new and biofilm-laden pipes. Additionally, the influence of Pb initial concentration on the rate of its accumulation onto the pipes was examined. The results revealed greater biofilm biomass on the PEX-A pipes compared to the copper and HDPE pipes. More negative zeta potential was found for the biofilm-laden plastic pipes compared to the new plastic pipes. After five days of Pb exposure under stagnant conditions, the biofilm-laden PEX-A (980 μg m[-2]) and HDPE (1170 μg m[-2]) pipe accumulated more than three times the Pb surface loading compared to the new PEX-A (265 μg m[-2]) and HDPE pipes (329 μg m[-2]), respectively. However, under flow conditions, Pb accumulation on biofilm-laden plastic pipes was lower than on the new pipes. Moreover, with increasing the initial Pb concentration, greater rates of Pb surface accumulation were found for the biofilm-laden pipes compared to the new pipes under stagnant conditions. First-order kinetics models best described the Pb accumulation onto both new and biofilm-laden water pipes under both stagnant and flow conditions.}, } @article {pmid37690248, year = {2023}, author = {Jiang, S and Shang, X and Chen, G and Zhao, M and Kong, H and Huang, Z and Zheng, X}, title = {Effects of regular zooplankton supplement on the bacterial communities and process performance of biofilm for wastewater treatment.}, journal = {Journal of environmental management}, volume = {345}, number = {}, pages = {118933}, doi = {10.1016/j.jenvman.2023.118933}, pmid = {37690248}, issn = {1095-8630}, abstract = {Biofilm processing technologies were widely used for wastewater treatment due to its advantages of low cost and easy management. However, the aging biofilms inevitably decrease the purification efficiency and increase the sludge production, which limited the widely application of biofilms technologies in rural area. In this study, we proposed a novel strategy by introducing high-trophic organisms to prey on low-trophic organisms, and reduce the aged biofilms and enhance treatment efficiencies in rural wastewater treatment. The effect of three typical zooplankton (Paramecium, Daphnia, and Rotifer) supplement on the purification efficiency and biofilm properties in the contact oxidation process were investigated, and the reaction conditions were optimized by an orthogonal experiment. Under optimal conditions, the biofilms weight decreased 67.6%, the oxygen consumption rate of biofilms increased 9.4%, and wastewater treatment efficiency was obviously increased after zooplankton supplement. Microbial sequencing results demonstrated that the zooplankton optimize the contact oxidation process by altering the bacterial genera mainly Diaphorobacter, Thermomonas, Alicycliphilus and Comamonas. This research provides insight into mechanism of the zooplankton supplement in biological contact oxidation process and provides a feasible strategy for improving the rural sewage treatment technology.}, } @article {pmid37690227, year = {2023}, author = {Geng, H and Sun, X and Zhang, X and Yuan, Y}, title = {Efficient titanium surface modified using bifunctional chimeric peptides to prevent biofilm formation by multiple microorganisms.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {230}, number = {}, pages = {113534}, doi = {10.1016/j.colsurfb.2023.113534}, pmid = {37690227}, issn = {1873-4367}, abstract = {It is still a challenge to prevent the formation of bacterial biofilms on the surfaces of oral implants. A chemical peptide with binding and antibacterial properties may be a promising agent if used to modify titanium (Ti) surfaces to inhibit biofilm formation. In this study, peptides were designed by linking the antimicrobial sequence derived from human β-defensin-3 (hBD-3) to the Ti-binding peptide-1 (TBP-1) sequence by using a triple glycine (G) linker. The antimicrobial activity and biocompatibility characteristics of the chemical-peptide-modified Ti surface were then evaluated and the potential antibacterial mechanism was investigated. This study demonstrated that the chemical-peptide-modified surface exhibited satisfactory bactericidal activities against Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis. In addition to its potent bacteria-killing efficacy, the surface-immobilised chemical peptide also demonstrated excellent biocompatibility to L929 cells. Moreover, the disruption of the integrity of the bacterial membrane partially revealed the antibacterial mechanism of the peptide. This study demonstrated the potential of chemical-peptide-modified Ti surfaces for preventing the occurrence of peri-implant diseases, thereby providing a promising approach to improving the survival rate of oral implants.}, } @article {pmid37690201, year = {2023}, author = {Ahmadi, N and Abbasi, M and Torabian, A and van Loosdrecht, MCM and Ducoste, J}, title = {Biotransformation of micropollutants in moving bed biofilm reactors under heterotrophic and autotrophic conditions.}, journal = {Journal of hazardous materials}, volume = {460}, number = {}, pages = {132232}, doi = {10.1016/j.jhazmat.2023.132232}, pmid = {37690201}, issn = {1873-3336}, abstract = {We investigated the transformation of four pharmaceuticals (Diclofenac, Naproxen, Ibuprofen and Carbamazepine) in a moving bed biofilm reactor subjected to different COD/N ratios in four experimental phases. The shift from medium to high range COD/N ratio (i.e., 5:1 to 100:1) intensified the competition between heterotrophs and nitrifying communities, leading to a transition from co-existence of heterotrophic and autotrophic conditions with high COD removal and nitrification rate in phase I to dominant heterotrophic conditions in phase II. At lower range COD/N ratios (i.e., 1:2 and 1:8) in phase III and IV, autotrophic conditions prevailed, resulting in increased nitrification rates and high abundance of amoA gene in the biofilm. Such shifts in the operating condition were accompanied by notable changes in the biofilm concentrations, composition and abundance of microbial populations as well as biodiversity in the biofilms, which collectively affected the degradation rates of the pharmaceuticals. We observed higher kinetic rates per unit of biofilm concentration under autotrophic conditions compared to heterotrophic conditions for all compounds except Naproxen, indicating the importance of nitrification in the transformation of such compounds. The results also revealed a positive relationship between biodiversity and biomass-normalized kinetic rates of most compounds.}, } @article {pmid37690815, year = {2023}, author = {Obana, N}, title = {[Study on biofilm formation and heterogeneity in Clostridium perfringens].}, journal = {Nihon saikingaku zasshi. Japanese journal of bacteriology}, volume = {78}, number = {2}, pages = {159-165}, doi = {10.3412/jsb.78.159}, pmid = {37690815}, issn = {1882-4110}, abstract = {Many bacteria form biofilms and survive in the actual environment. Biofilms are not only a major form of bacteria but are also involved in tolerance to environmental stresses and antibiotics, suggesting the association with bacterial pathogenesis. Cells within biofilms display phenotypic heterogeneity; thus, even bacteria, unicellular organisms, can functionally differentiate and show multicellular behavior. Therefore, it is necessary to understand bacteria as a population to control their survival and pathogenesis in the actual environment. Previously, we found that Clostridium perfringens, an anaerobic pathogenic bacterium, form different structures in different temperatures and phenotypic heterogeneity on biofilm matrix gene expression within the biofilm. In this article, I summarize the results of our research on biofilms and their heterogeneity, the mechanisms of post-transcriptional gene expression regulation of virulence genes, and bacteria-host interactions mediated by extracellular membrane vesicles.}, } @article {pmid37689855, year = {2023}, author = {Kim, SH and Lee, H and Park, MK}, title = {Isolation, characterization, and application of a novel, lytic phage vB_SalA_KFSST3 with depolymerase for the control of Salmonella and its biofilm on cantaloupe under cold temperature.}, journal = {Food research international (Ottawa, Ont.)}, volume = {172}, number = {}, pages = {113062}, doi = {10.1016/j.foodres.2023.113062}, pmid = {37689855}, issn = {1873-7145}, abstract = {This study investigated the efficacy of a novel Salmonella phage with depolymerase activity to control S. Typhimurium (ST) and its biofilm on cantaloupes, for the first time, under simulated cold temperature. vB_SalA_KFSST3 forming a halo zone was isolated and purified from a slaughterhouse with a final concentration of 12.1 ± 0.1 log PFU/mL. Based on the morphological and bioinformatics analyses, vB_SalA_KFSST3 was identified as a novel phage belonging to the family Ackermannviridae. Before employing the phage on cantaloupe, its genetic characteristics, specificity, stability, and bactericidal effect were investigated. Genetic analyses confirmed its safety and identified endolysin and two depolymerase domains possessing antibiofilm potential. In addition, the phage exhibited a broad specificity with great efficiencies toward five Salmonella strains at 4 °C, 22 °C, and 37 °C, as well as stable lytic activity over a wide range of pHs (3 to 11) and temperatures (-20 °C to 60 °C). The optimal multiplicity of infection (MOI) and exposure time of phage were determined to be 100 and 2 h, respectively, based on the highest bacterial reduction of ∼2.7 log CFU/mL. Following the formation of ST biofilm on cantaloupe at 4 °C and 22 °C, the cantaloupe was treated with phage at an MOI of 100 for 2 h. The antibiofilm efficacy of phage was evaluated via the plate count method, confocal laser scanning microscopy, and scanning electron microscopy (SEM). The initial biofilm population at 22 °C was significantly greater and more condensed than that at 4 °C. After phage treatment, biofilm population and the percentage of viable ST in biofilm were reduced by ∼4.6 log CFU/cm[2] and ∼90% within 2 h, respectively, which were significantly greater than those at 22 °C (∼2.0 log CFU/cm[2] and ∼45%) (P < 0.05). SEM images also confirmed more drastic destruction of the cohesive biofilm architecture at 4 °C than at 22 °C. As a result of its cold temperature-robust lytic activity and the contribution of endolysin and two depolymerases, vB_SalA_KFSST3 demonstrated excellent antibiofilm efficacy at cold temperature, highlighting its potential as a promising practical biocontrol agent for the control of ST and its biofilm.}, } @article {pmid37689727, year = {2023}, author = {Alaei, M and Aghakhani, F and Falsafi, S and Mazaheri, H and Behrouzi, A}, title = {Introduce a novel post-biotic against Pseudomonas aeruginosa biofilm formation using Escherchia coli Nissle1917 outer membrane vesicles.}, journal = {BMC research notes}, volume = {16}, number = {1}, pages = {201}, pmid = {37689727}, issn = {1756-0500}, abstract = {Pseudomonas aeruginosa is an opportunistic bacterial pathogen that can cause acute infections as well as chronic ones in humans. The expression of algD and PpyR genes involved in biofilm formation in clinical isolates of P. aeruginosa in the presence of Escherichia coli Nissle1917 outer membranes vesicles (EcN OMVs) was evaluated. All isolates were tested for biofilm formation. qPCR and disk diffusion were used to identify the expression of algD and PpyR genes, and antimicrobial resistance, respectively. EcN OMVs caused a more significant loss of algD and PpyR expression, compared with the control group. EcN OMVs contain a variety of biomolecules that are capable of influencing the biofilm formation genes. EcN OMVs treatment reduced P. aeruginosa biofilm formation significantly, which emphasizes their positive role in inhibiting biofilm formation. As a result, EcN OMVs can be used as new therapeutic strategies for inhibiting P. aeruginosa biofilm formation.}, } @article {pmid37689424, year = {2023}, author = {Lee, JI and Kim, SS and Kang, DH}, title = {Characteristics of Staphylococcus aureus biofilm matured in tryptic soy broth, low-fat milk, or whole milk samples along with inactivation by 405 nm light combined with folic acid.}, journal = {Food microbiology}, volume = {116}, number = {}, pages = {104350}, doi = {10.1016/j.fm.2023.104350}, pmid = {37689424}, issn = {1095-9998}, abstract = {In the present study, the characteristics of Staphylococcus aureus biofilms matured in tryptic soy broth (TSB), low-fat milk, or whole milk samples were identified along with their resistance to 405 nm light with or without folic acid. Phenotypic properties of carbohydrate and protein contents in extracellular polymeric substance (EPS) of S. aureus biofilms matured in different conditions were identified. The carbohydrate content was higher in the biofilm matured in low-fat milk (1.27) than the samples matured in whole milk (0.58) and TSB (0.10). Protein content in the EPS of biofilm was higher in the sample matured in whole milk (6.59) than the samples matured in low-fat milk (3.24) and TSB (2.08). Moreover, the maturation condition had a significant effect on the membrane lipid composition of the biofilm, producing more unsaturated fatty acids in biofilm matured in milk samples. These changes in biofilm matured in milk samples increased the resistance of S. aureus to 405 nm light in the presence of folic acid (LFA). Additionally, transcriptomic analysis was conducted to identify the response of S. aureus biofilm to LFA treatment. Several genes related to DNA and protein protection from oxidative stress along with biofilm accumulation were overexpressed in the LFA-treated biofilms. These results indicate the maturation of S. aureus biofilm in various samples and the biofilms responses to bactericidal treatments.}, } @article {pmid37689420, year = {2023}, author = {Wang, X and Ma, K and Zhang, C and Ji, F and Chen, L and Zhang, X and Mahsa, GC and Azarpazhooh, E and Ajami, M and Rui, X and Li, W}, title = {The interaction among Kluyveromyces marxianus G-Y4, Lacticaseibacillus paracasei GL1, and Lactobacillus helveticus SNA12 and signaling molecule AI-2 participate in the formation of biofilm.}, journal = {Food microbiology}, volume = {116}, number = {}, pages = {104369}, doi = {10.1016/j.fm.2023.104369}, pmid = {37689420}, issn = {1095-9998}, abstract = {In this study, two strains of lactic acid bacteria (Lacticaseibacillus paracasei GL1 and Lactobacillus helveticus SNA12) and one yeast strain of Kluyveromyces marxianus G-Y4 (G-Y4) isolated from Tibetan kefir grains were co-cultured. It was found that the addition of G-Y4 could not only promote the growth of lactic acid bacteria, but also increase the release of metabolites (lactic acid, ethanol, and amino nitrogen). Furthermore, the addition of live cells and cell-free fermentation supernatant (CFS) of G-Y4 could increase the ability of biofilm formation. Morever, the surface characteristics results showed that the addition of G-Y4 live cells could enhance the aggregation ability and hydrophobicity of LAB. Meanwhile, adding live cells and CFS of G-Y4 could promote the release of signaling molecule AI-2 and enhance the expression of the LuxS gene related to biofilm formation. In addition, Fourier-transform infrared spectroscopy and chemical composition analysis were used to investigate the composition of the biofilm, and the results indicated that the biofilm was mainly composed of a small amount of protein but it was rich in polysaccharides including glucose, galactose, and mannose with different ratios. Finally, the formation of biofilm could delay the decline of the number of viable bacteria in storage fermented milk.}, } @article {pmid37688296, year = {2023}, author = {Luo, B and Li, Z and Wang, Q and Wang, C}, title = {Synergistic Role of Biofilm-Associated Genes and Efflux Pump Genes in Tigecycline Resistance of Acinetobacter baumannii.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {29}, number = {}, pages = {e940704}, doi = {10.12659/MSM.940704}, pmid = {37688296}, issn = {1643-3750}, abstract = {BACKGROUND Previous research reported that the resistance mechanism of Acinetobacter baumannii resistance to tigecycline was mainly related to the overexpression of the AdeABC efflux pump system. Biofilm formation is a notable pathogenesis of A. baumannii infections and antibiotic resistance. Our study explores the latent relevance of biofilm-associated genes and efflux pump genes in A. baumannii tigecycline resistance. MATERIAL AND METHODS A total of 78 clinical samples were collected from October 2018 to October 2019. Seventy-two clinically isolated A. baumannii strains were divided into a tigecycline-resistant Acinetobacter baumannii (TR-AN) group and tigecycline-sensitive Acinetobacter baumannii (TS-AN) group by tigecycline minimum inhibitory concentration tests. The biofilm formation of the 2 groups was observed using crystal violet staining. Furthermore, biofilm-related genes and efflux pump genes were analyzed by RT-PCR. RESULTS The biofilm-forming rate of the TR-AN group was 82.2%, and that of the TS-AN group was 14.8%. The biofilm synthesis gene bfs was 91.3% positive in the TR-AN group, significantly higher than in the TS-AN group at the transcription level (P<0.05). The minimum inhibitory concentration of tigecycline was higher in the TR-AN group with biofilm formation than in the TR-AN group without biofilm formation (P<0.05). The efflux pump AdeB gene was 95.2% positive in the TR-AN group with biofilm formation and 38.7% positive in the TR-AN group without biofilm formation. CONCLUSIONS The biofilm formation of A. baumannii may be positively related to tigecycline resistance ability because of the co-expression of the bfs gene and the AdeB efflux pump gene. The enhanced transcription level of bfs and AdeB promotes biofilm formation to improve the resistance of A. baumannii to tigecycline.}, } @article {pmid37687153, year = {2023}, author = {Hamouda, RA and Alharthi, MA and Alotaibi, AS and Alenzi, AM and Albalawi, DA and Makharita, RR}, title = {Biogenic Nanoparticles Silver and Copper and Their Composites Derived from Marine Alga Ulva lactuca: Insight into the Characterizations, Antibacterial Activity, and Anti-Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {17}, pages = {}, doi = {10.3390/molecules28176324}, pmid = {37687153}, issn = {1420-3049}, abstract = {Bacterial pathogens cause pain and death, add significantly to the expense of healthcare globally, and pose a serious concern in many aspects of daily life. Additionally, they raise significant issues in other industries, including pharmaceuticals, clothing, and food packaging. Due to their unique properties, a great deal of attention has been given to biogenic metal nanoparticles, nanocomposites, and their applications against pathogenic bacteria. This study is focused on biogenic silver and copper nanoparticles and their composites (UL/Ag2 O-NPS, Ul/CuO-NPs, and Ul/Ag/Cu-NCMs) produced by the marine green alga Ulva lactuca. The characterization of biogenic nanoparticles UL/Ag2 O-NPS and Ul/CuO-NPs and their composites Ul/Ag/Cu-NCMs has been accomplished by FT-IR, SEM, TEM, EDS, XRD, and the zeta potential. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) experiments were conducted to prove antibacterial activity against both Gram-positive and Gram-negative bacteria and anti-biofilm. The FTIR spectroscopy results indicate the exiting band at 1633 cm[-1], which represents N-H stretching in nanocomposites, with a small shift in both copper and silver nanoparticles, which is responsible for the bio-reduction of nanoparticles. The TEM image reveals that the Ul/Ag/Cu-NCMs were hexagonal, and the size distribution ranged from 10 to 35 nm. Meanwhile, Ul/CuO-NPs are rod-shaped, whereas UL/Ag2 O-NPS are spherical. The EDX analysis shows that Cu metal was present in a high weight percentage over Ag in the case of bio-Ag/Cu-NCMs. The X-ray diffraction denotes that Ul/Ag/Cu-NCMs, UL/CuO-NPs, and UL/Ag2 O-NPS were crystalline. The results predicted by the zeta potential demonstrate that Ul/Ag/Cu-NCMs were more stable than Ul/CuO-NPs. The antibacterial activity of UL/Ag2 O-NPS, Ul/Ag/Cu-NCMs, and UL/CuO-NPs was studied against eleven Gram-negative and Gram-positive multidrug-resistant bacterial species. The maximum inhibition zones were obtained with UL/Ag2 O-NPS, followed by Ul/Ag/Cu-NCMs and Ul/CuO-NPs in all the tested bacteria. The maximum anti-biofilm percentage formed by E. coli KY856933 was obtained with UL/Ag2 O-NPS. These findings suggest that the synthesized nanoparticles might be a great alternative for use as an antibacterial agent against different multidrug-resistant bacterial strains.}, } @article {pmid37687052, year = {2023}, author = {Kietrungruang, K and Sookkree, S and Sangboonruang, S and Semakul, N and Poomanee, W and Kitidee, K and Tragoolpua, Y and Tragoolpua, K}, title = {Ethanolic Extract Propolis-Loaded Niosomes Diminish Phospholipase B1, Biofilm Formation, and Intracellular Replication of Cryptococcus neoformans in Macrophages.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {17}, pages = {}, doi = {10.3390/molecules28176224}, pmid = {37687052}, issn = {1420-3049}, support = {MT-AMS 621135903//Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University/ ; }, abstract = {Secretory phospholipase B1 (PLB1) and biofilms act as microbial virulence factors and play an important role in pulmonary cryptococcosis. This study aims to formulate the ethanolic extract of propolis-loaded niosomes (Nio-EEP) and evaluate the biological activities occurring during PLB1 production and biofilm formation of Cryptococcus neoformans. Some physicochemical characterizations of niosomes include a mean diameter of 270 nm in a spherical shape, a zeta-potential of -10.54 ± 1.37 mV, and 88.13 ± 0.01% entrapment efficiency. Nio-EEP can release EEP in a sustained manner and retains consistent physicochemical properties for a month. Nio-EEP has the capability to permeate the cellular membranes of C. neoformans, causing a significant decrease in the mRNA expression level of PLB1. Interestingly, biofilm formation, biofilm thickness, and the expression level of biofilm-related genes (UGD1 and UXS1) were also significantly reduced. Pre-treating with Nio-EEP prior to yeast infection reduced the intracellular replication of C. neoformans in alveolar macrophages by 47%. In conclusion, Nio-EEP mediates as an anti-virulence agent to inhibit PLB1 and biofilm production for preventing fungal colonization on lung epithelial cells and also decreases the intracellular replication of phagocytosed cryptococci. This nano-based EEP delivery might be a potential therapeutic strategy in the prophylaxis and treatment of pulmonary cryptococcosis in the future.}, } @article {pmid37687010, year = {2023}, author = {Hernández-Moreno, LV and Pabón-Baquero, LC and Prieto-Rodriguez, JA and Patiño-Ladino, OJ}, title = {Bioactive Compounds from P. pertomentellum That Regulate QS, Biofilm Formation and Virulence Factor Production of P. aeruginosa.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {17}, pages = {}, doi = {10.3390/molecules28176181}, pmid = {37687010}, issn = {1420-3049}, support = {110177758105//MINISTERIO DE CIENCIA, TECNOLOGÍA E INNOVACIÓN/ ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen responsible for many nosocomial infections. This bacterium uses Quorum Sensing (QS) to generate antimicrobial resistance (AMR) so its disruption is considered a novel approach. The current study describes the antibiofilm and QS inhibitory potential of extract and chemical components from Piper pertomentellum. The methodo- logy included the phytochemical study on the aerial part of the species, the determination of QS inhibition efficacy on Chromobacterium violaceum and the evaluation of the effect on biofilm formation and virulence factors on P. aeruginosa. The phytochemical study led to the isolation and identification of a new piperamide (ethyltembamide 1), together with four known amides (tembamide acetate 2, cepharadione B 3, benzamide 4 and tembamide 5). The results indicated that the ethanolic extract and some fractions reduced violacein production in C. violaceum, however, only the ethanolic extract caused inhibition of biofilm formation of P. aeruginosa on polystyrene microtiter plates. Finally, the investigation determined that molecules (1-5) inhibited the formation of biofilms (50% approximately), while compounds 2-4 can inhibit pyocyanin and elastase production (30-50% approximately). In this way, the study contributes to the determination of the potential of extract and chemical constituents from P pertomentellum to regulate the QS system in P. aeruginosa.}, } @article {pmid37685913, year = {2023}, author = {Avila-Novoa, MG and González-Torres, B and González-Gómez, JP and Guerrero-Medina, PJ and Martínez-Chávez, L and Martínez-Gonzáles, NE and Chaidez, C and Gutiérrez-Lomelí, M}, title = {Genomic Insights into Listeria monocytogenes: Organic Acid Interventions for Biofilm Prevention and Control.}, journal = {International journal of molecular sciences}, volume = {24}, number = {17}, pages = {}, doi = {10.3390/ijms241713108}, pmid = {37685913}, issn = {1422-0067}, abstract = {Listeria monocytogenes is an important pathogen that has been implicated in foodborne illness. The aim of the present study was to investigate the diversity of virulence factors associated with the mechanisms of pathogenicity, persistence, and formation of biofilm L. monocytogenes by tandem analysis of whole-genome sequencing. The lineages that presented L. monocytogenes (LmAV-2, LmAV-3, and LmAV-6) from Hass avocados were lineages I and II. Listeria pathogenicity island 1 (LIPI-1) and LIPI-2 were found in the isolates, while LIPI-3 and Listeria genomic island (LGI-2) only was in IIb. Stress survival island (SSI-1) was identified in lineage I and II. In the in silico analysis, resistance genes belonging to several groups of antibiotics were detected, but the bcrABC and transposon Tn6188 related to resistance to quaternary ammonium salts (QACs) were not detected in L. monocytogenes. Subsequently, the anti-L. monocytogenes planktonic cell effect showed for QACs (MIC = 6.25 ppm/MBC = 100 ppm), lactic acid (MBC = 1 mg/mL), citric acid (MBC = 0.5 mg/mL) and gallic acid (MBC = 2 mg/mL). The anti-biofilm effect with organic acids (22 °C) caused a reduction of 4-5 log10 cfu/cm[2] after 10 min against control biofilm L. monocytogenes formed on PP than SS. This study is an important contribution to understanding the genomic diversity and epidemiology of L. monocytogenes to establish a control measure to reduce the impact on the environment and the consumer.}, } @article {pmid37683855, year = {2023}, author = {Liu, S and Zhang, Z and Gu, P and Yang, K and Huang, X and Li, M and Miao, H}, title = {Elucidating applied voltage on the fate of antibiotic resistance genes in microbial electrolysis cell: Focusing on its transmission between anolyte and biofilm microbes.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166901}, doi = {10.1016/j.scitotenv.2023.166901}, pmid = {37683855}, issn = {1879-1026}, abstract = {Microbial electrolysis cell (MEC) system to treat wastewater containing antibiotics has been researched actively in past years. However, the fate of antibiotic resistant genes (ARGs) in MEC is not fully revealed. The effect of applied voltage on the migration of ARGs between anolyte and biofilm microbes via examining the microbial physiology and abundances of macrolide resistance genes (MRGs) and mobile genetic elements (MGEs) was elucidated in this research. Results showed that the abundance of MRGs and MGEs was decreased in the anolyte, but the abundance of MRGs and MGEs was increased on the electrode biofilm, indicating their transmission from anolyte to biofilm microbes. Increased applied voltage enhanced adenosine triphosphate (ATP), reactive oxygen species (ROS), and cell membrane permeability of electrode microorganisms. The structure of the electrode microbial community was shifted through applied voltage, and the abundance of electroactive microorganisms (Geobacter, Azospirillum and Dechlorobacter) was significantly improved. Network analysis revealed that Geobacter and Geothrix were potential hosts for MRGs. Therefore, the horizontal and vertical gene transfer of ARGs could be increased by the applied voltage, leading to the enriched ARGs at the electrode biofilm. This study provides evidence and insights into the transmission of ARGs between anolyte and biofilm microbes. SYNOPSIS: This study revealed the effect of applied voltage on ARGs in MEC and the potential migration mechanism of ARGs.}, } @article {pmid37681687, year = {2023}, author = {Zhao, J and Guo, X and Yang, J and Xie, Y and Zheng, Y}, title = {In Situ Polymerization of Methylene Blue on Bacterial Cellulose for Photodynamic/Photoelectricity Synergistic Inhibition of Bacterial Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsami.3c09449}, pmid = {37681687}, issn = {1944-8252}, abstract = {In the context of long-term antimicrobial treatment, the emergence of bacterial resistance poses a significant challenge. Therefore, there is a pressing need to develop novel antimicrobial materials and methods that can effectively and safely combat microbial infections. This study focuses on the synthesis of bacterial cellulose-polymethylene blue (BC-PMB) with integrated photodynamic and photoelectric antimicrobial properties. The polymerization of methyl blue (MB) onto bacterial celluloses (BC) was achieved, and through comprehensive computational analyses using density functional theory (DFT) and molecular dynamics simulations, it was confirmed that this polymerization greatly enhanced the binding efficiency between methylene blue and BC. Additionally, polymethylene blue (PMB) exhibited superior photoexcitation efficiency and conductivity compared to its precursor. When BC-PMB was exposed to a 30 mW 660 nm light source for 30 min, the material demonstrated a remarkable antimicrobial efficacy of 93.99% against Escherichia coli and 98.58% against Staphylococcus aureus. Furthermore, the synergistic effect of photodynamic and photoelectric antimicrobial mechanisms exhibited long-term inhibitory capabilities against bacterial biofilms.}, } @article {pmid37680974, year = {2023}, author = {Richter-Dahlfors, A and Kärkkäinen, E and Choong, FX}, title = {Fluorescent optotracers for bacterial and biofilm detection and diagnostics.}, journal = {Science and technology of advanced materials}, volume = {24}, number = {1}, pages = {2246867}, doi = {10.1080/14686996.2023.2246867}, pmid = {37680974}, issn = {1468-6996}, abstract = {Effective treatment of bacterial infections requires methods that accurately and quickly identify which antibiotic should be prescribed. This review describes recent research on the development of optotracing methodologies for bacterial and biofilm detection and diagnostics. Optotracers are small, chemically well-defined, anionic fluorescent tracer molecules that detect peptide- and carbohydrate-based biopolymers. This class of organic molecules (luminescent conjugated oligothiophenes) show unique electronic, electrochemical and optical properties originating from the conjugated structure of the compounds. The photophysical properties are further improved as donor-acceptor-donor (D-A-D)-type motifs are incorporated in the conjugated backbone. Optotracers bind their biopolymeric target molecules via electrostatic interactions. Binding alters the optical properties of these tracer molecules, shown as altered absorption and emission spectra, as well as ON-like switch of fluorescence. As the optotracer provides a defined spectral signature for each binding partner, a fingerprint is generated that can be used for identification of the target biopolymer. Alongside their use for in situ experimentation, optotracers have demonstrated excellent use in studies of a number of clinically relevant microbial pathogens. These methods will find widespread use across a variety of communities engaged in reducing the effect of antibiotic resistance. This includes basic researchers studying molecular resistance mechanisms, academia and pharma developing new antimicrobials targeting biofilm infections and tests to diagnose biofilm infections, as well as those developing antibiotic susceptibility tests for biofilm infections (biofilm-AST). By iterating between the microbial world and that of plants, development of the optotracing technology has become a prime example of successful cross-feeding across the boundaries of disciplines. As optotracers offers a capacity to redefine the way we work with polysaccharides in the microbial world as well as with plant biomass, the technology is providing novel outputs desperately needed for global impact of the threat of antimicrobial resistance as well as our strive for a circular bioeconomy.}, } @article {pmid37680749, year = {2023}, author = {Dumitrascu, F and Caira, MR and Avram, S and Buiu, C and Udrea, AM and Vlad, IM and Zarafu, I and Ioniță, P and Nuță, DC and Popa, M and Chifiriuc, MC and Limban, C}, title = {Repurposing anti-inflammatory drugs for fighting planktonic and biofilm growth. New carbazole derivatives based on the NSAID carprofen: synthesis, in silico and in vitro bioevaluation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1181516}, doi = {10.3389/fcimb.2023.1181516}, pmid = {37680749}, issn = {2235-2988}, abstract = {INTRODUCTION: One of the promising leads for the rapid discovery of alternative antimicrobial agents is to repurpose other drugs, such as nonsteroidal anti-inflammatory agents (NSAIDs) for fighting bacterial infections and antimicrobial resistance.

METHODS: A series of new carbazole derivatives based on the readily available anti-inflammatory drug carprofen has been obtained by nitration, halogenation and N-alkylation of carprofen and its esters. The structures of these carbazole compounds were assigned by NMR and IR spectroscopy. Regioselective electrophilic substitution by nitration and halogenation at the carbazole ring was assigned from H NMR spectra. The single crystal X-ray structures of two representative derivatives obtained by dibromination of carprofen, were also determined. The total antioxidant capacity (TAC) was measured using the DPPH method. The antimicrobial activity assay was performed using quantitative methods, allowing establishment of the minimal inhibitory/bactericidal/biofilm eradication concentrations (MIC/MBC/MBEC) on Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) strains. Computational assays have been performed to assess the drug- and lead-likeness, pharmacokinetics (ADME-Tox) and pharmacogenomics profiles.

RESULTS AND DISCUSSION: The crystal X-ray structures of 3,8-dibromocarprofen and its methyl ester have revealed significant differences in their supramolecular assemblies. The most active antioxidant compound was 1i, bearing one chlorine and two bromine atoms, as well as the CO2Me group. Among the tested derivatives, 1h bearing one chlorine and two bromine atoms has exhibited the widest antibacterial spectrum and the most intensive inhibitory activity, especially against the Gram-positive strains, in planktonic and biofilm growth state. The compounds 1a (bearing one chlorine, one NO2 and one CO2Me group) and 1i (bearing one chlorine, two bromine atoms and a CO2Me group) exhibited the best antibiofilm activity in the case of the P. aeruginosa strain. Moreover, these compounds comply with the drug-likeness rules, have good oral bioavailability and are not carcinogenic or mutagenic. The results demonstrate that these new carbazole derivatives have a molecular profile which deserves to be explored further for the development of novel antibacterial and antibiofilm agents.}, } @article {pmid37680458, year = {2023}, author = {van Charante, F and Martínez-Pérez, D and Guarch-Pérez, C and Courtens, C and Sass, A and Choińska, E and Idaszek, J and Van Calenbergh, S and Riool, M and Zaat, SAJ and Święszkowski, W and Coenye, T}, title = {3D-printed wound dressings containing a fosmidomycin-derivative prevent Acinetobacter baumannii biofilm formation.}, journal = {iScience}, volume = {26}, number = {9}, pages = {107557}, pmid = {37680458}, issn = {2589-0042}, abstract = {Acinetobacter baumannii causes a wide range of infections, including wound infections. Multidrug-resistant A. baumannii is a major healthcare concern and the development of novel treatments against these infections is needed. Fosmidomycin is a repurposed antimalarial drug targeting the non-mevalonate pathway, and several derivatives show activity toward A. baumannii. We evaluated the antimicrobial activity of CC366, a fosmidomycin prodrug, against a collection of A. baumannii strains, using various in vitro and in vivo models; emphasis was placed on the evaluation of its anti-biofilm activity. We also developed a 3D-printed wound dressing containing CC366, using melt electrowriting technology. Minimal inhibitory concentrations of CC366 ranged from 1 to 64 μg/mL, and CC366 showed good biofilm inhibitory and moderate biofilm eradicating activity in vitro. CC366 successfully eluted from a 3D-printed dressing, the dressings prevented the formation of A. baumannnii wound biofilms in vitro and reduced A. baumannii infection in an in vivo mouse model.}, } @article {pmid37679831, year = {2023}, author = {Maillard, JY and Centeleghe, I}, title = {How biofilm changes our understanding of cleaning and disinfection.}, journal = {Antimicrobial resistance and infection control}, volume = {12}, number = {1}, pages = {95}, pmid = {37679831}, issn = {2047-2994}, abstract = {Biofilms are ubiquitous in healthcare settings. By nature, biofilms are less susceptible to antimicrobials and are associated with healthcare-associated infections (HAI). Resistance of biofilm to antimicrobials is multifactorial with the presence of a matrix composed of extracellular polymeric substances and eDNA, being a major contributing factor. The usual multispecies composition of environmental biofilms can also impact on antimicrobial efficacy. In healthcare settings, two main types of biofilms are present: hydrated biofilms, for example, in drains and parts of some medical devices and equipment, and environmental dry biofilms (DSB) on surfaces and possibly in medical devices. Biofilms act as a reservoir for pathogens including multi-drug resistant organisms and their elimination requires different approaches. The control of hydrated (drain) biofilms should be informed by a reduction or elimination of microbial bioburden together with measuring biofilm regrowth time. The control of DSB should be measured by a combination of a reduction or elimination in microbial bioburden on surfaces together with a decrease in bacterial transfer post-intervention. Failure to control biofilms increases the risk for HAI, but biofilms are not solely responsible for disinfection failure or shortcoming. The limited number of standardised biofilm efficacy tests is a hindrance for end users and manufacturers, whilst in Europe there are no approved standard protocols. Education of stakeholders about biofilms and ad hoc efficacy tests, often academic in nature, is thus paramount, to achieve a better control of biofilms in healthcare settings.}, } @article {pmid37679756, year = {2023}, author = {Fujii, T and Tochio, T and Nishifuji, K}, title = {Erythritol alters gene transcriptome signatures, cell growth, and biofilm formation in Staphylococcus pseudintermedius.}, journal = {BMC veterinary research}, volume = {19}, number = {1}, pages = {146}, pmid = {37679756}, issn = {1746-6148}, abstract = {BACKGROUND: Erythritol was found to inhibit the growth of microorganisms. The present study aimed to demonstrate the growth inhibition of Staphylococcus pseudintermedius by erythritol and to define the changes in gene transcription signatures induced by erythritol. Changes in the gene transcription profiles were analysed by RNA sequencing and quantitative reverse transcription PCR. Gene ontology analysis was performed to assign functional descriptions to the genes.

RESULTS: Erythritol inhibited S. pseudintermedius growth in a dose-dependent manner. We then performed a transcriptome analysis of S. pseudintermedius with and without 5% (w/w) erythritol exposure to validate the mechanism of growth inhibition. We revealed that erythritol induced up-regulation of three genes (ptsG, ppdK, and ppdkR) that are related to the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS). Glucose supplementation restored the up-regulation of the PTS-related genes in response to erythritol. In addition, erythritol down-regulated eleven genes that are located in a single pur-operon and inhibited biofilm formation of S. pseudintermedius.

CONCLUSIONS: These findings indicated that erythritol antagonistically inhibits PTS-mediated glucose uptake, thereby exerting a growth inhibitory effect on S. pseudintermedius. Moreover, erythritol inhibits the 'de novo' IMP biosynthetic pathway that may contribute to biofilm synthesis in S. pseudintermedius.}, } @article {pmid37679355, year = {2023}, author = {Wang, S and Zhao, Y and Breslawec, AP and Liang, T and Deng, Z and Kuperman, LL and Yu, Q}, title = {Strategy to combat biofilms: a focus on biofilm dispersal enzymes.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {63}, pmid = {37679355}, issn = {2055-5008}, support = {Grant No. 23A310029//Education Department of Henan Province (Department of Education, Henan Province)/ ; }, abstract = {Bacterial biofilms, which consist of three-dimensional extracellular polymeric substance (EPS), not only function as signaling networks, provide nutritional support, and facilitate surface adhesion, but also serve as a protective shield for the residing bacterial inhabitants against external stress, such as antibiotics, antimicrobials, and host immune responses. Biofilm-associated infections account for 65-80% of all human microbial infections that lead to serious mortality and morbidity. Tremendous effort has been spent to address the problem by developing biofilm-dispersing agents to discharge colonized microbial cells to a more vulnerable planktonic state. Here, we discuss the recent progress of enzymatic eradicating strategies against medical biofilms, with a focus on dispersal mechanisms. Particularly, we review three enzyme classes that have been extensively investigated, namely glycoside hydrolases, proteases, and deoxyribonucleases.}, } @article {pmid37678679, year = {2023}, author = {Sabino, YNV and de Araújo Domingues, KC and Mathur, H and Gómez-Mascaraque, LG and Drouin, G and Martínez-Abad, A and Tótola, MR and Abreu, LM and Cotter, PD and Mantovani, HC}, title = {Exopolysaccharides produced by Bacillus spp. inhibit biofilm formation by Staphylococcus aureus strains associated with bovine mastitis.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {126689}, doi = {10.1016/j.ijbiomac.2023.126689}, pmid = {37678679}, issn = {1879-0003}, abstract = {Bovine mastitis is a costly disease in the dairy sector worldwide. Here the objective was to identify and characterize anti-biofilm compounds produced by Bacillus spp. against S. aureus associated with bovine mastitis. Results showed that cell-free supernatants of three Bacillus strains (out of 33 analysed) reduced S. aureus biofilm formation by approximately 40 % without affecting bacterial growth. The anti-biofilm activity was associated with exopolysaccharides (EPS) secreted by Bacillus spp. The EPS decreased S. aureus biofilm formation in a dose-dependent manner, inhibiting biofilm formation by 83 % at 1 mg/mL. The EPS also showed some biofilm disruption activity (up to 36.4 %), which may be partially mediated by increased expression of the aur gene. The characterization of EPS produced by Bacillus velezensis 87 and B. velezensis TR47II revealed macromolecules with molecular weights of 31.2 and 33.7 kDa, respectively. These macromolecules were composed mainly of glucose (mean = 218.5 μg/mL) and mannose (mean = 241.5 μg/mL) and had similar functional groups (pyranose ring, beta-type glycosidic linkage, and alkynes) as revealed by FT-IR. In conclusion, this study shows the potential applications of EPS produced by B. velezensis as an anti-biofilm compound that could contribute to the treatment of bovine mastitis caused by S. aureus.}, } @article {pmid37676573, year = {2022}, author = {Yang, Y and Pan, D and Tang, Y and Li, J and Zhu, K and Yu, Z and Zhu, L and Wang, Y and Chen, P and Li, C}, title = {H3-T6SS of Pseudomonas aeruginosa PA14 contributes to environmental adaptation via secretion of a biofilm-promoting effector.}, journal = {Stress biology}, volume = {2}, number = {1}, pages = {55}, pmid = {37676573}, issn = {2731-0450}, support = {2021YFA0909600//Key Technologies Research and Development Program/ ; 32100034//Young Scientists Fund (CN)/ ; 32100149//Young Scientists Fund/ ; 31970114//National Natural Science Foundation of China/ ; }, abstract = {Microbial species often occur in complex communities and exhibit intricate synergistic and antagonistic interactions. To avoid predation and compete for favorable niches, bacteria have evolved specialized protein secretion systems. The type VI secretion system (T6SS) is a versatile secretion system widely distributed among Gram-negative bacteria that translocates effectors into target cells or the extracellular milieu via various physiological processes. Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases, and it has three independent T6SSs (H1-, H2-, and H3-T6SS). In this study, we found that the H3-T6SS of highly virulent P. aeruginosa PA14 is negatively regulated by OxyR and OmpR, which are global regulatory proteins of bacterial oxidative and acid stress. In addition, we identified a H3-T6SS effector PA14_33970, which is located upstream of VgrG3. PA14_33970 interacted directly with VgrG3 and translocated into host cells. Moreover, we found that H3-T6SS and PA14_33970 play crucial roles in oxidative, acid, and osmotic stress resistance, as well as in motility and biofilm formation. PA14_33970 was identified as a new T6SS effector promoting biofilm formation and thus named TepB. Furthermore, we found that TepB contributes to the virulence of P. aeruginosa PA14 toward Caenorhabditis elegans. Overall, our study indicates that H3-T6SS and its biofilm-promoting effector TepB are regulated by OxyR and OmpR, both of which are important for adaptation of P. aeruginosa PA14 to multiple stressors, providing insights into the regulatory mechanisms and roles of T6SSs in P. aeruginosa.}, } @article {pmid37675686, year = {2023}, author = {Sheena, MS and Singh, R}, title = {Biofilm profile of candidaemia isolates.}, journal = {The Indian journal of medical research}, volume = {}, number = {}, pages = {}, doi = {10.4103/ijmr.ijmr_2214_21}, pmid = {37675686}, issn = {0971-5916}, } @article {pmid37673259, year = {2023}, author = {Ray, AS and Rajasekaran, M and Uddin, M and Kandasamy, R}, title = {Laccase driven biocatalytic oxidation to reduce polymeric surface hydrophobicity: An effective pre-treatment strategy to enhance biofilm mediated degradation of polyethylene and polycarbonate plastics.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166721}, doi = {10.1016/j.scitotenv.2023.166721}, pmid = {37673259}, issn = {1879-1026}, abstract = {Plastic pollution is a major global environmental issue due to its structural complexity and poor biodegradability. Biological approaches are appropriate due to cost effectiveness and environmental friendliness, however effective polymer degradation is still in its infancy. As biological treatments are slower than physical and chemical approaches, they could be applied in conjunction with pre-treatment techniques such as photo-oxidation, heat treatment, and chemical treatments. But these processes lead to high energy consumption and hazardous secondary pollution. To address these concerns, an enzymatic pre-treatment strategy has been proposed in this study, with an aim of promoting surface oxidation on the plastics leading to improved hydrophilicity. This in turn, facilitates the surface attachment of microbes, ultimately, accelerating biodegradation. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy analyses confirmed the surface oxidation of the polyethylene (PE) and polycarbonate (PC) plastics mediated by the action of laccase enzyme. Contact angle measurement witnessed the increased hydrophilicity of the treated plastics. Following, a potential biofilm forming microbial consortium has been employed for the biodegradation of enzyme treated plastics. SEM analysis indicated the increased formation of corrosive pits and surface aberrations on the enzymatically pre-treated plastics and Confocal Laser Scanning microscopy (CLSM) analysis exhibited the enhanced biofilm formation and exopolysaccharide deposition on the pre-treated PE and PC. In addition, X-ray photoelectron spectroscopy (XPS) revealed the reduction in the elemental composition of carbon with an increment in the oxygen composition of plastics. Gel permeation chromatography (GPC) further confirmed the greater reduction in the molecular weights of the plastics subjected to integrated enzymatic and biofilm treatment than only biofilm treated plastics. This is the first report on the integration of enzymatic pre-treatment with the biofilm mediated microbial degradation to achieve enhanced treatment of plastics which demonstrated to be a promising technology for the effective mitigation of plastic pollution.}, } @article {pmid37673249, year = {2023}, author = {Zhang, H and Zhang, SS and Zhang, W and Ma, WC and Pan, Y and Chen, L and Zhu, L and Li, YP and Li, JR}, title = {Clarification of the phosphorus release mechanism for recovering phosphorus from biofilm sludge in alternating aerobic/anaerobic biofilm system.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166811}, doi = {10.1016/j.scitotenv.2023.166811}, pmid = {37673249}, issn = {1879-1026}, abstract = {A novel wastewater treatment plant process was constructed to overcome the challenge of simultaneous nitrate removal and phosphorus (P) recovery. The results revealed that the P and nitrate removal efficiency rose from 39.0 % and 48.4 % to 92.8 % and 93.6 % after 136 days of operation, and the total P content in the biofilm (TPbiofilm) rose from 15.8 mg/g SS to 57.8 mg/g SS. Moreover, the increase of TPbiofilm changed the metabolic mode of denitrifying polyphosphate accumulating organisms (DPAOs), increasing the P concentration of the enriched stream to 172.5 mg/L. Furthermore, the acid/alkaline fermentation led to the rupture of the cell membrane, which released poly-phosphate and ortho-phosphate of cell/EPS in DPAOs and released metal‑phosphorus (CaP and MgP). In addition, high-throughput sequencing analysis demonstrated that the relative abundance of DPAOs involved in P storage increased, wherein the abundance of Acinetobacter and Saprospiraceae rose from 8.0 % and 4.1 % to 16.1 % and 14.0 %. What's more, the highest P recovery efficiency (98.3 ± 1.1 %) could be obtained at optimal conditions for struvite precipitation (pH = 7.56 and P: N: Mg = 1.87:3.66:1) through the response surface method (RSM) simulation, and the precipitates test analysis indicated that P recovery from biofilm sludge was potentially operable. This research was of great essentiality for exploring the recovery of P from biofilm sludge.}, } @article {pmid37672071, year = {2023}, author = {Rouhani, M and Valizadeh, V and Bakhshandeh, H and Hosseinzadeh, SA and Molasalehi, S and Atyabi, SM and Norouzian, D}, title = {Improved anti-biofilm activity and long-lasting effects of novel serratiopeptidase immobilized on cellulose nanofibers.}, journal = {Applied microbiology and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37672071}, issn = {1432-0614}, abstract = {Today, enzymatic treatment is a progressive field in combating biofilm producing pathogens. In this regard, serratiopeptidase, a medicinally important metalloprotease, has been recently highlighted as an enzyme with proved anti-biofilm activity. In the present study, in order to increase the long-lasting effects of the enzyme, serratiopeptidase and the novel engineered forms with enhanced anti-biofilm activity were immobilized on the surface of cellulose nanofibers (CNFs) as a natural polymer with eminent properties. For this, recombinant serratiopeptidases including the native and previously designed enzymes were produced, purified and conjugated to the CNF by chemical and physical methods. Immobilization was confirmed using different scanning and microscopic methods. The enzyme activity was assessed using casein hydrolysis test. Enzyme release analysis was performed using dialysis tube method. Anti-biofilm activity of free and immobilized enzymes has been examined on Staphylococcus aureus and Pseudomonas aeruginosa strains. Finally, cytotoxicity of enzyme-conjugated CNFs was performed by MTT assay. The casein hydrolysis results confirmed fixation of all recombinant enzymes on CNFs by chemical method; however, inadequate fixation of these enzymes was found using cold atmospheric plasma (CAP). The AFM, FTIR, and SEM analysis confirmed appropriate conjugation of enzymes on the surface of CNFs. Immobilization of enzymes on CNFs improved the anti-biofilm activity of serratiopeptidase enzymes. Interestingly, the novel engineered serratiopeptidase (T344 [8-339ss]) exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms. In conclusion, incorporation of serratiopeptidases into CNFs improves their anti-biofilm activities without baring any cytotoxicity. KEY POINTS: • Enzymes were successfully immobilized on cellulose nanofibers using chemical method. • Immobilization of enzymes on CNFs improved their anti-biofilm activity. • T344 [8-339ss] exhibited the highest anti-biofilm activity in both conjugated and non-conjugated forms.}, } @article {pmid37671283, year = {2023}, author = {Friberg, M and Woeller, K and Iberi, V and Mancheno, PP and Riedeman, J and Bohman, L and Davis, CC}, title = {Development of in vitro methods to model the impact of vaginal lactobacilli on Staphylococcus aureus biofilm formation on menstrual cups as well as validation of recommended cleaning directions.}, journal = {Frontiers in reproductive health}, volume = {5}, number = {}, pages = {1162746}, pmid = {37671283}, issn = {2673-3153}, abstract = {INTRODUCTION: Menstrual cups (MC) are a reusable feminine hygiene product. A recent publication suggested that Staphylococcus aureus (S. aureus) biofilms can form on MCs which may lead to increased risk of menstrual Toxic Shock Syndrome (mTSS). Additionally, there is concern that buildup of residual menses may contribute to microbial growth and biofilm formation further increasing mTSS risk. Quantitative and qualitative analysis of in vitro tests were utilized to determine if S. aureus biofilm could form on MC in the presence of the keystone species Lactobacillus after 12 h of incubation. The methodology was based on a modification of an anaerobic in vitro method that harnesses the keystone species hypothesis by including a representative of vaginal lactic acid bacteria.

METHODS: MCs were incubated anaerobically for 12 h in Vaginal Defined Media (VDM) with the two morphologically distinct bacteria, Lactobacillus gasseri (L. gasseri) and S. aureus. Colony Forming Units (CFU) for each organism from the VDM broth and sonicated MC were estimated. In addition, a separate experiment was conducted where S. aureus was grown for 12 h in the absence of L. gasseri. Qualitative analysis for biofilm formation utilized micro-CT (µ-CT) and cryogenic scanning electron microscopy (Cryo-SEM).

RESULTS: Samples collected from the media control had expected growth of both organisms after 12 h of incubation. Samples collected from VDM broth were similar to media control at the end of the 12-h study. Total S. aureus cell density on MC following sonication/rinsing was minimal. Results when using a monoculture of S. aureus demonstrated that there was a significant growth of the organism in the media control and broth as well as the sonicated cups indicating that the presence of L. gasseri was important for controlling growth and adherence of S. aureus. Few rod-shaped bacteria (L. gasseri) and cocci (S. aureus) could be identified on the MCs when grown in a dual species culture inoculum and no biofilm was noted via µ-CT and cryo-SEM. Additionally, efforts to model and understand the validity of the current labeled recommendations for MC cleaning in-between uses are supported.

DISCUSSION: The data support continued safe use of the Tampax® cup when used and maintained as recommended.}, } @article {pmid37669734, year = {2023}, author = {Osama, A and Kinnawy, MA and Moussa, MS and Riechelmann, C and Hosney, H}, title = {Mathematical modelling and comparative analysis of treatment technologies for upgrading wastewater treatment plants: A case study of biofilm reactors in El-Gouna, Egypt.}, journal = {Environmental research}, volume = {}, number = {}, pages = {117008}, doi = {10.1016/j.envres.2023.117008}, pmid = {37669734}, issn = {1096-0953}, abstract = {In recent years, Moving Bed Biofilm Reactors (MBBRs) have been preferred to conventional processes with suspended biomass. The main reason for this preference is that it can achieve better removal efficiencies than conventional systems with smaller footprints. However, unlocking the full potential of MBBRs in large-scale WWTPs remains challenging in real life. In this study, the performance of three different treatment technologies, Extended Aeration Activated Sludge (EAAS), Hybrid Fixed Bed Biofilm Reactor (HFBBR), and Hybrid Moving Bed Biofilm Reactor (HMBBR), was investigated over a year in a WWTP located in El-Gouna, Egypt. The COD removal efficiencies of the three systems were comparable, with the EAAS achieving 93.5%, HFBBR 94%, and HMBRR 95%. Nevertheless, the NH4 removal efficiency of the EAAS was slightly lower (97.5%) than that of the HFBBR and the HMBBR, that achieved a removal efficiency of 98%. BioWin Software was able to mimic the real case of the WWTP of El-Gouna and critically defined all plant limitations and operational data. Different simulations were modeled to test the hydraulic and organic loading capacities of the three systems under different scenarios and operating conditions. The HMBBR system failed to withstand the increase in organic load because of the biomass sloughing effect and subsequently high TSS loads in the settlers. Biomass sloughing overloaded the settlers and lead to biomass loss in the effluent. As the settleability of the HMBBR sludge was significantly lower than for the HFBBR the TSS loss in the effluent happened that much earlier that the moving carrier application had an adverse effect contradicting with the primary purpose of adding media carriers. Model simulations and data analysis findings were used to recommend the most suitable configuration for upgrading an existing system using the attached growth technique with all kinetic parameters and operational conditions. The recommended configuration focuses mainly on the separation of plastic media in a compartment with a very low hydraulic retention time to absorb the incoming shock load.}, } @article {pmid37669396, year = {2023}, author = {Li, Z and Gong, T and Wu, Q and Zhang, Y and Zheng, X and Li, Y and Ren, B and Peng, X and Zhou, X}, title = {Lysine lactylation regulates metabolic pathways and biofilm formation in Streptococcus mutans.}, journal = {Science signaling}, volume = {16}, number = {801}, pages = {eadg1849}, doi = {10.1126/scisignal.adg1849}, pmid = {37669396}, issn = {1937-9145}, abstract = {In eukaryotes, lactate produced during glycolysis is involved in regulating multiple metabolic processes through lysine lactylation (Kla). To explore the potential link between metabolism and Kla in prokaryotes, we investigated the distribution of Kla in the cariogenic bacterium Streptococcus mutans during planktonic growth in low-sugar conditions and in biofilm-promoting, high-sugar conditions. We identified 1869 Kla sites in 469 proteins under these two conditions, with the biofilm growth state showing a greater number of lactylated sites and proteins. Although high sugar increased Kla globally, it reduced lactylation of RNA polymerase subunit α (RpoA) at Lys[173]. Lactylation at this residue inhibited the synthesis of extracellular polysaccharides, a major constituent of the cariogenic biofilm. The Gcn5-related N-acetyltransferase (GNAT) superfamily enzyme GNAT13 exhibited lysine lactyltransferase activity in cells and lactylated Lys[173] in RpoA in vitro. Either GNAT13 overexpression or lactylation of Lys[173] in RpoA inhibited biofilm formation. These results provide an overview of the distribution and potential functions of Kla and improve our understanding of the role of lactate in the metabolic regulation of prokaryotes.}, } @article {pmid37669036, year = {2023}, author = {Guan, N and Shi, Y and Tong, H and Yang, Y and Li, J and Guo, D and Wang, X and Shan, Z and Lü, X and Shi, C}, title = {Inhibition of Cronobacter sakazakii Biofilm Formation and Expression of Virulence Factors by Coenzyme Q0.}, journal = {Foodborne pathogens and disease}, volume = {}, number = {}, pages = {}, doi = {10.1089/fpd.2023.0040}, pmid = {37669036}, issn = {1556-7125}, abstract = {In this study, we investigated the inhibitory effects of coenzyme Q0 (CoQ0) on biofilm formation and the expression of virulence genes by Cronobacter sakazakii. We found that the minimum inhibitory concentration of CoQ0 against C. sakazakii strains ATCC29544 and ATCC29004 was 100 μg/mL, while growth curve assays showed that subinhibitory concentrations (SICs) of CoQ0 for both strains were 6.4, 3.2, 1.6 and 0.8 μg/mL. Assays exploring the inhibition of specific biofilm formation showed that SICs of CoQ0 inhibited biofilm formation by C. sakazakii in a dose-dependent manner, which was confirmed by scanning electron microscopy and confocal laser scanning microscopy analyses. CoQ0 inhibited the swimming and swarming motility of C. sakazakii and reduced its ability to adhere to and invade HT-29 cells. In addition, CoQ0 impeded the ability of C. sakazakii to survive and replicate within RAW 264.7 cells. Finally, real-time polymerase chain reaction analysis confirmed that nine C. sakazakii genes associated with biofilm formation and virulence were downregulated in response to CoQ0 treatment. Overall, our findings suggest that CoQ0 is a promising antibiofilm agent and provide new insights for the prevention and control of infections caused by C. sakazakii.}, } @article {pmid37668830, year = {2023}, author = {Dos Santos, EAR and Tadielo, LE and Schmiedt, JA and Possebon, FS and Pereira, MO and Pereira, JG and Dos Santos Bersot, L}, title = {Effect of ginger essential oil and 6-gingerol on a multispecies biofilm of Listeria monocytogenes, Salmonella Typhimurium, and Pseudomonas aeruginosa.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37668830}, issn = {1678-4405}, abstract = {The objective of this study was to evaluate the potential antimicrobial and antibiofilm effect of ginger essential oil (GEO) and 6-gingerol on a multispecies biofilm formed by Listeria monocytogenes, Salmonella Typhimurium, and Pseudomonas aeruginosa on a polypropylene surface. The minimum inhibitory concentration concentrations obtained for GEO were 100 and 50 mg/mL and for 6-gingerol 1.25 mg/mL. Sessile cell counts ranged within 5.35-7.35 log CFU/cm[2] in the control biofilm, with the highest sessile growth at 72 h. GEO treatments acted on the total population regardless of concentration at 1 and 48 h. L. monocytogenes behaved similarly to the total population, showing GEO action at 1 h and keeping the same pattern at 48, 72, and 96 h. Better action on S. Typhimurium was obtained at times of 1, 72, and 96 h. P. aeruginosa showed logarithmic reduction only when treated with GEO 50 mg at 24 h. As for 6-gingerol, in general, there was no significant action (p > 0.05) on the evaluated sessile cells. GEO showed antimicrobial activity against L. monocytogenes, S. Typhimurium, and P. aeruginosa, acting as an inhibitor of biofilm formation. As for 6-gingerol, it was considered a possible antimicrobial agent but without efficacy during biofilm formation.}, } @article {pmid37667809, year = {2023}, author = {Lin, H and Zhou, C and Yu, KH and Lin, YS and Wang, LB and Zhang, Y and Liu, SX and Xu, WY and Sun, Y and Zhou, TL and Cao, JM and Ye, JZ}, title = {Glabridin Functions as a Quorum Sensing Inhibitor to Inhibit Biofilm Formation and Swarming Motility of Multidrug-Resistant Acinetobacter baumannii.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {5697-5705}, pmid = {37667809}, issn = {1178-6973}, abstract = {OBJECTIVE: Acinetobacter baumannii is a hazardous bacterium that causes hospital-acquired nosocomial infections, and the advent of multidrug-resistant A. baumannii (MDR-AB) strains is concerning. Novel antibacterial therapeutic strategies must be developed. The biological effects of glabridin on MDR-AB were investigated in this study.

METHODS: The minimum inhibitory concentrations (MICs) of glabridin against eight clinical MDR-AB strains were determined using the broth microdilution technique. Crystal violet staining was used to assess biofilm development, which has significant contribution to bacterial resistance. Swarming motility was measured according to surface growth zone of MDR-AB on LB agar medium. qRT-PCR was used to evaluate the expression of quorum sensing genes abaI and abaR. Glabridin and routinely used therapeutic antimicrobial agents were tested for synergistic action using the checkerboard method.

RESULTS: According to our findings, glabridin suppressed MDR-AB growth at high doses (512-1024 μg/mL). The 1/4 MIC of glabridin significantly decreased MDR-AB biofilm formation by 19.98% (P < 0.05), inhibited MDR-AB motility by 44.27% (P < 0.05), whereas the 1/2 MIC of glabridin dramatically reduced MDR-AB biofilm development by 27.43% (P < 0.01), suppressed MDR-AB motility by 50.64% (P < 0.05). Mechanistically, glabridin substantially downregulated the expression of quorum sensing-related genes abaI and abaR by up to 39.12% (P < 0.001) and 25.19% (P < 0.01), respectively. However, no synergistic effect between glabridin and antibacterial drugs was found.

CONCLUSION: Glabridin might be a quorum sensing inhibitor that inhibits MDR-AB biofilm development and swarming motility.}, } @article {pmid37666301, year = {2023}, author = {Makabenta, JMV and Nabawy, A and Chattopadhyay, AN and Jeon, T and Park, J and Lo, PC and Nosovitski, S and Huang, R and Li, CH and Jiang, M and Rotello, VM}, title = {Antimicrobial polymer-loaded hydrogels for the topical treatment of multidrug-resistant wound biofilm infections.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jconrel.2023.09.002}, pmid = {37666301}, issn = {1873-4995}, abstract = {Integration of antimicrobial polymeric nanoparticles into hydrogel materials presents a promising strategy to address multidrug-resistant biofilm infections. Here we report an injectable hydrogel loaded with engineered cationic antimicrobial polymeric nanoparticles (PNPs) for the effective topical treatment of severe wound biofilm infections. The PNPs demonstrated biofilm penetration and disruption, resulting in the eradication of resistant and persister cells that reside within the biofilm. Significantly, PNPs did not elicit resistance development even after multiple exposures to sub-therapeutic doses. In vitro studies showed PNPs significantly reduced prolonged inflammation due to infection and promoted fibroblast migration. These PNPs were then incorporated into Poloxamer 407 (P407) hydrogels and utilized as an inert carrier for PNPs to provide a controlled and sustained topical release of the antimicrobial nanoparticles at the wound area. In vivo studies using a mature (4-day) wound biofilm infection in a murine model mimicking severe human wound infections demonstrated provided 99% bacterial biofilm clearance and significantly enhanced wound healing. Overall, this work demonstrated the efficacy and selectivity of the antimicrobial polymer-loaded hydrogel platform as a topical treatment for difficult-to-treat wound biofilm infections.}, } @article {pmid37667093, year = {2023}, author = {Martha-Lucero, N and Viniegra-González, G and González-Olivares, L and Cruz-Guerrero, A}, title = {Biofilm formation by agave epiphytic lactic acid bacteria fed with agave fructans.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {11}, pages = {299}, pmid = {37667093}, issn = {1573-0972}, abstract = {The aim of this work was to find out if biofilms can be made by lactic acid bacteria (LAB) isolated from agave plants using agave fructans as sole carbohydrate substrates or if it was necessary to use fructose as a breakdown product of such polymers. This is part of a research project geared to develop industrial lactic acid production from agave fructans, an abundant raw material in Mexico's agave plantations. Present results showed that nine strains of LAB isolated from Agave salmiana and belonging to genus Lacticaseibacillus and Enterococcus produced exopolysaccharides directly from agave fructans to a greater extent than with fructose. The best polysaccharide productions in planktonic cultures were Lacticaseibacillus paracasei strains DG2, DG3, DG4 and DG8. Furthermore, all nine LAB strains produced biofilms on polystyrene microplates, much better with agave fructans than with fructose. In most strains, biofilm formation was favored at pH from 6.0 to 6.5, except for strains DG7 and DG9 where pH 5.5 was optimal. Biofilm formation required between 3 and 5 days of incubation in all Lacticaseibacillus paracasei strains, whereas Enterococcus faecium required a little less of 3 days. Present results support the straight use of agave fructans to develop LAB biofilms using agave epiphytic bacteria. This finding simplifies upstream processing of agave fructans to be used for future lactic acid fermentation in LAB biofilm reactors.}, } @article {pmid37665947, year = {2023}, author = {Kresse-Walczak, K and Meissner, H and Mauer, R and Trips, E and Boening, K}, title = {Evaluation of a protocol to assess a novel artificial biofilm equivalent for dentures-A prospective clinical pilot study.}, journal = {Gerodontology}, volume = {}, number = {}, pages = {}, doi = {10.1111/ger.12715}, pmid = {37665947}, issn = {1741-2358}, support = {427547277//Deutsche Forschungsgemeinschaft/ ; }, abstract = {OBJECTIVES: This pilot study aimed to carry out preliminary tests of the removability of an artificial biofilm equivalent (ABE) and to verify the reproducibility of the ABE testing protocol for a planned main study.

BACKGROUND: There is a lack of data to develop suitable artificial biofilm substitutes, which may be helpful to perform denture hygiene education and to carry out in vitro examinations of oral hygiene products.

MATERIALS AND METHODS: This single-group, prospective, longitudinal, interventional pilot study was conducted in Dresden (Germany) from February until December 2020. Participants were recruited who wore fully functional upper complete dentures. Denture biofilm was grown on acrylic specimens by wearing dentures for 12 h and 36 h using intraoral appliances. Acrylic specimens were coated with ABEs of three compositions: chitosan (ChS) 0.3 g, methylcellulose (MC) 1.7 g; ChS 0.2 g, MC 1.8 g; ChS 0.1 g, MC 1.9 g (labelled 1.7MC, 1.8MC and 1.9MC, respectively). All specimens underwent standardised mechanical brushing. The percentages of remaining biofilm (POB) were measured.

RESULTS: Thirty-one participants were prescreened, and eight (26%) were included. The appliances were well tolerated, and biofilm was collected. ABE was prepared and brushed as planned. Three and six brushing strokes were needed to remove 12-h and 36-h natural denture biofilm, respectively. Correspondingly, three brushing strokes were needed to remove 1.9MC ABE and six brushing strokes to remove 1.8MC and 1.7MC ABE. A reproducibility of ABE removal was indicated.

CONCLUSION: The removability of ABE and the ABE testing protocol were feasible and reproducible for conducting the future main study.}, } @article {pmid37665578, year = {2023}, author = {Maisat, W and Yuki, K}, title = {Volatile anesthetic isoflurane exposure facilitates Enterococcus biofilm infection.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {37}, number = {10}, pages = {e23186}, doi = {10.1096/fj.202301128R}, pmid = {37665578}, issn = {1530-6860}, support = {R01GM127600//HHS | NIH | National Institute of General Medical Sciences (NIGMS)/ ; }, abstract = {Enterococcus faecalis (E. faecalis) is one of the major pathogenic bacteria responsible for surgical site infections. Biofilm infections are major hospital-acquired infections. Previous studies suggested that ions could regulate biofilm formation in microbes. Volatile anesthetics, frequently administered in surgical setting, target ion channels. Here, we investigated the role of ion channels/transporters and volatile anesthetics in the biofilm formation by E. faecalis MMH594 strain and its ion transporter mutants. We found that a chloride transporter mutant significantly reduced biofilm formation compared to the parental strain. Downregulation of teichoic acid biosynthesis in the chloride transporter mutant impaired biofilm matrix formation and cellular adhesion, leading to mitigated biofilm formation. Among anesthetics, isoflurane exposure enhanced biofilm formation in vitro and in vivo. The upregulation of de novo purine biosynthesis pathway by isoflurane exposure potentially enhanced biofilm formation, an essential process for DNA, RNA, and ATP synthesis. We also demonstrated that isoflurane exposure to E. faecalis increased cyclic-di-AMP and extracellular DNA production, consistent with the increased purine biosynthesis. We further showed that isoflurane enhanced the enzymatic activity of phosphoribosyl pyrophosphate synthetase (PRPP-S). With the hypothesis that isoflurane directly bound to PRPP-S, we predicted isoflurane binding site on it using rigid docking. Our study provides a better understanding of the underlying mechanisms of E. faecalis biofilm formation and highlights the potential impact of an ion transporter and volatile anesthetic on this process. These findings may lead to the development of novel strategies for preventing E. faecalis biofilm formation and improving patient outcomes in clinical settings.}, } @article {pmid37664878, year = {2023}, author = {Lohrmann, C and Holm, C}, title = {A novel model for biofilm initiation in porous media flow.}, journal = {Soft matter}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3sm00575e}, pmid = {37664878}, issn = {1744-6848}, abstract = {Bacteria often form biofilms in porous environments where an external flow is present, such as soil or filtration systems. To understand the initial stages of biofilm formation, one needs to study the interactions between cells, the fluid and the confining geometries. Here, we present an agent based numerical model for bacteria that takes into account the planktonic stage of motile cells as well as surface attachment and biofilm growth in a lattice Boltzmann fluid. In the planktonic stage we show the importance of the interplay between complex flow and cell motility when determining positions of surface attachment. In the growth stage we show the applicability of our model by investigating how external flow and biofilm stiffness determine qualitative colony morphologies as well as quantitative measurements of, e.g., permeability.}, } @article {pmid37664011, year = {2023}, author = {Kenkel, A and Karande, R and Bühler, K}, title = {Evaluating scaling of capillary photo-biofilm reactors for high cell density cultivation of mixed trophies artificial microbial consortia.}, journal = {Engineering in life sciences}, volume = {23}, number = {9}, pages = {e2300014}, pmid = {37664011}, issn = {1618-0240}, abstract = {Capillary biofilm reactors (CBRs) are attractive for growing photoautotrophic bacteria as they allow high cell-density cultivation. Here, we evaluated the CBR system's suitability to grow an artificial consortium composed of Synechocystis sp. PCC 6803 and Pseudomonas sp. VBL120. The impact of reactor material, flow rate, pH, O2, and medium composition on biomass development and long-term biofilm stability at different reactor scales was studied. Silicone was superior over other materials like glass or PVC due to its excellent O2 permeability. High flow rates of 520 μL min[-1] prevented biofilm sloughing in 1 m capillary reactors, leading to a 54% higher biomass dry weight combined with the lowest O2 concentration inside the reactor compared to standard operating conditions. Further increase in reactor length to 5 m revealed a limitation in trace elements. Increasing trace elements by a factor of five allowed for complete surface coverage with a biomass dry weight of 36.8 g m[-2] and, thus, a successful CBR scale-up by a factor of 25. Practical application: Cyanobacteria use light energy to upgrade CO2, thereby holding the potential for carbon-neutral production processes. One of the persisting challenges is low cell density due to light limitations and O2 accumulation often occurring in established flat panel or tubular photobioreactors. Compared to planktonic cultures, much higher cell densities (factor 10 to 100) can be obtained in cyanobacterial biofilms. The capillary biofilm reactor (CBR) offers good growth conditions for cyanobacterial biofilms, but its applicability has been shown only on the laboratory scale. Here, a first scale-up study based on sizing up was performed, testing the feasibility of this system for large-scale applications. We demonstrate that by optimizing nutrient supply and flow conditions, the system could be enlarged by factor 25 by enhancing the length of the reactor. This reactor concept, combined with cyanobacterial biofilms and numbering up, holds the potential to be applied as a flexible, carbon-neutral production platform for value-added compounds.}, } @article {pmid37663210, year = {2023}, author = {Sharma, P and Dhawan, P and Rajpal, SK and Sharma, R}, title = {A Comparison of Antimicrobial Efficacy of Silver-based Preventive Restorations (Silver Nitrate, Silver Diamine Fluoride, and Silver Nanoparticles) against Streptococcus mutans Monospecies Biofilm Model.}, journal = {International journal of clinical pediatric dentistry}, volume = {16}, number = {Suppl 1}, pages = {S13-S19}, pmid = {37663210}, issn = {0974-7052}, abstract = {AIM: The ability of the Streptococcus mutans (S. mutans) to form biofilms is not only crucial in the initiation of early childhood caries (ECC) but is also a challenge to its treatment. The current management protocols focus on remineralization and use of antimicrobial formulations which penetrate biofilms, control their formation, and decrease the incidence of caries in children. The paradigm shift toward preventive protocols and increasing antibiotic resistance rekindled the use of silver as a promising antibacterial agent. To gain further insight into the therapeutic potential, aim of the present study was to compare the antibacterial efficacy of silver-based preventive restorations [silver nitrate (AgNO3), silver diamine fluoride (SDF), and silver nanoparticles (AgNPs)] against S. mutans species.

MATERIALS AND METHODS: Using an ex vivo monospecies biofilm model of S. mutans; the antimicrobial efficacy of three treatment groups (SDF, AgNO3, and AgNPs) was evaluated.

RESULTS: There was a significant difference between the negative control and three treatment groups (SDF, AgNO3, and AgNPs). The results showed that the mean diameter of inhibition zones obtained in biofilms treated with AgNPs was 40.3 ± 0.25 mm which was greater than both SDF (37.7 ± 0.18 mm) and AgNO3 (36.26 ± 0.18 mm).

CONCLUSION: The study concluded that the number of viable bacteria was significantly reduced by all three medicaments (p < 0.05). However, AgNPs showed the highest antimicrobial activity in comparison to SDF and AgNO3 against S. mutans biofilm.

CLINICAL SIGNIFICANCE: The present study thus supports that AgNPs are a promising preventive anticaries agent due to their better antibacterial activity in comparison to other silver-based preventive restorations and can be effectively used as an alternative to SDF or AgNO3 for the noninvasive treatment of ECC in the young.

HOW TO CITE THIS ARTICLE: Sharma P, Dhawan P, Rajpal SK, et al. A Comparison of Antimicrobial Efficacy of Silver-based Preventive Restorations (Silver Nitrate, Silver Diamine Fluoride, and Silver Nanoparticles) against Streptococcus mutans Monospecies Biofilm Model. Int J Clin Pediatr Dent 2023;16(S-1):S13-S19.}, } @article {pmid37662851, year = {2023}, author = {Akturk, E and Melo, LDR and Oliveira, H and Crabbé, A and Coenye, T and Azeredo, J}, title = {Combining phages and antibiotic to enhance antibiofilm efficacy against an in vitro dual species wound biofilm.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100147}, pmid = {37662851}, issn = {2590-2075}, abstract = {Chronic wound management is extremely challenging because of the persistence of biofilm-forming pathogens, such as Pseudomonas aeruginosa and Staphylococcus aureus, which are the prevailing bacterial species that co-infect chronic wounds. Phage therapy has gained an increased interest to treat biofilm-associated infections, namely when combined with antibiotics. Here, we tested the effect of gentamicin as a co-adjuvant of phages in a dual species-biofilm wound model formed on artificial dermis. The biofilm-killing capacity of the tested treatments was significantly increased when phages were combined with gentamicin and applied multiple times as multiple dose (three doses, every 8 h). Our results suggest that gentamycin is an effective adjuvant of phage therapy particularly when applied simultaneously with phages and in three consecutive doses. The multiple and simultaneous dose treatment seems to be essential to avoid bacterial resistance development to each of the antimicrobial agents.}, } @article {pmid37662773, year = {2023}, author = {Bisht, B and Verma, M and Sharma, R and Chauhan, PK and Pant, K and Kim, H and Vlaskin, MS and Kumar, V}, title = {Development of yeast and microalgae consortium biofilm growth system for biofuel production.}, journal = {Heliyon}, volume = {9}, number = {9}, pages = {e19353}, pmid = {37662773}, issn = {2405-8440}, abstract = {BACKGROUND: The current study aimed to develop a laboratory-scale biofilm photobioreactor system for biofuel production.

SCOPE & APPROACH: During the investigation, Jute was discovered to be the best, cheap, hairy, open-pored supporting material for biofilm formation. Microalgae & yeast consortium was used in this study for biofilm formation.

CONCLUSION: The study identified microalgae and yeast consortium as a promising choice and ideal partners for biofilm formation with the highest biomass yield (47.63 ± 0.93 g/m[2]), biomass productivity (4.39 ± 0.29 to 7.77 ± 0.05 g/m[2]/day) and lipid content (36%) over 28 days cultivation period, resulting in a more sustainable and environmentally benign fuel that could become a reality in the near future.}, } @article {pmid37662325, year = {2023}, author = {Choi, A and Dong, K and Williams, E and Pia, L and Batagower, J and Bending, P and Shin, I and Peters, DI and Kaspar, JR}, title = {Human Saliva Modifies Growth, Biofilm Architecture and Competitive Behaviors of Oral Streptococci.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.08.21.554151}, pmid = {37662325}, abstract = {The bacteria within supragingival biofilms participate in complex exchanges with other microbes inhabiting the same niche. One example are the mutans group streptococci (Streptococcus mutan s), implicated in the development of tooth decay, and other health-associated commensal streptococci species. Previously, our group transcriptomically characterized intermicrobial interactions between S. mutans and several species of oral bacteria. However, these experiments were carried out in a medium that was absent of human saliva. To better mimic their natural environment, we first evaluated how inclusion of saliva affected growth and biofilm formation of eight streptococci species individually, and found saliva to positively benefit growth rates while negatively influencing biomass accumulation and altering spatial arrangement. These results carried over during evaluation of 29 saliva-derived isolates of various species. Surprisingly, we also found that addition of saliva increased the competitive behaviors of S. mutans in coculture competitions against commensal streptococci that led to increases in biofilm microcolony volumes. Through transcriptomically characterizing mono- and cocultures of S. mutans and Streptococcus oralis with and without saliva, we determined that each species developed a nutritional niche under mixed-species growth, with S. mutans upregulating carbohydrate uptake and utilization pathways while S. oralis upregulated genome features related to peptide uptake and glycan foraging. S. mutans also upregulated genes involved in oxidative stress tolerance, particularly manganese uptake, which we could artificially manipulate by supplementing in manganese to give it an advantage over its opponent. Our report highlights observable changes in microbial behaviors via leveraging environmental- and host-supplied resources over their competitors.}, } @article {pmid37660742, year = {2023}, author = {Kaur, M and Buyck, JM and Goormaghtigh, F and Decout, JL and Mozaheb, N and Mingeot-Leclercq, MP}, title = {Deficient P. aeruginosa in MlaA/VacJ outer membrane lipoprotein shows decrease in rhamnolipids secretion, motility, and biofilm formation, and increase in fluoroquinolones susceptibility and innate immune response.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104132}, doi = {10.1016/j.resmic.2023.104132}, pmid = {37660742}, issn = {1769-7123}, abstract = {P. aeruginosa, a Gram-negative bacterium that causes severe hospital acquired infections poses threat by its ability for adaptation to various growth modes and environmental conditions and by its intrinsic resistance to antibiotics. The latter is mainly due to the outer membrane (OM) asymmetry which is maintained by the Mla pathway resulting in the retrograde transport of glycerophospholipids from the OM to the inner membrane. It comprises six Mla proteins, including MlaA, an OM lipoprotein involved in the removal of glycerophospholipids mislocalized at the outer leaflet of OM. To investigate the role of P. aeruginosa OM asymmetry especially MlaA, this study investigated the effect of mlaA deletion on (i) the susceptibility to antibiotics, (ii) the secretion of virulence factors, the motility, biofilm formation, and (iii) the inflammatory response. mlaA deletion in P. aeruginosa ATCC27853 results in phenotypic changes including, an increase in fluoroquinolones susceptibility and in PQS (Pseudomonas Quinolone Signal) and TNF-α release and a decrease in rhamnolipids secretion, motility and biofilm formation. Investigating how the mlaA knockout impacts on antibiotic susceptibility, bacterial virulence and innate immune response will help to elucidate the biological significance of the Mla system and contribute to the understanding of MlaA in P. aeruginosa OM asymmetry.}, } @article {pmid37660303, year = {2023}, author = {Qais, FA and Khan, MS and Ahmad, I and Husain, FM and Arshad, M and Khan, A and Adil, M}, title = {Modulation of quorum sensing and biofilm of Gram-negative bacterial pathogens by Cinnamomum zeylanicum L.}, journal = {Microscopy research and technique}, volume = {}, number = {}, pages = {}, doi = {10.1002/jemt.24410}, pmid = {37660303}, issn = {1097-0029}, support = {RSPD2023R729//King Saud University/ ; }, abstract = {The development of antibiotic resistant microbial pathogens has become a global health threat and a major concern in modern medicine. The problem of antimicrobial resistance (AMR) has majorly arisen due to sub-judicious use of antibiotics in health care and livestock industry. A slow progress has been made in last two decades in discovery of new antibiotics. A new strategy in combatting AMR is to modulate or disarm the microbes for their virulence and pathogenicity. Plants are considered as promising source for new drugs against AMR pathogens. In this study, fraction-based screening of the Cinnamomum zeylanicum extract was performed followed by detailed investigation of antiquorum sensing and antibiofilm activities of the most active fraction that is, C. zeylanicum hexane fraction (CZHF). More than 75% reduction in violacein pigment of C. violaceum 12472 was overserved. CZHF successfully modulated the virulence of Pseudomonas aeruginosa PAO1 by 60.46%-78.35%. A similar effect was recorded against Serratia marcescens MTCC 97. A broad-spectrum inhibition of biofilm development was found in presence of sub-MICs of CZHF. The colonization of bacteria onto the glass coverslips was remarkably reduced apart from the reduction in exopolymeric substances. Alkaloids and terpenoids were found in CZHF. GC/MS analysis revealed the presence of cinnamaldehyde dimethyl acetal, 2-propenal, coumarin, and α-copaene as major phytocompounds. This study provides enough evidence to support potency of C. zeylanicum extract in targeting the virulence of Gram -ve pathogenic bacteria. The plant extract or active compounds can be developed as successful drugs after careful in vivo examination to target microbial infections. RESEARCH HIGHLIGHTS: Hexane fraction of Cinnamomum zeylanicum is active against QS and biofilms. The broad-spectrum antibiofilm activity was further confirmed by microscopic analysis. Dimethyl acetal, 2-propenal, coumarin, α-copaene, and so forth are major phytocompounds.}, } @article {pmid37659546, year = {2023}, author = {Li, F and Zhang, J and Liu, D and Yu, H and Li, C and Liu, Q and Chen, Z and Song, H}, title = {Engineering extracellular polymer substrates biosynthesis and carbon felt-carbon nanotube hybrid electrode to promote biofilm electroactivity and bioelectricity production.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166595}, doi = {10.1016/j.scitotenv.2023.166595}, pmid = {37659546}, issn = {1879-1026}, abstract = {Organic-rich thin stillage is a significant by-product of the liquor brewing industry, and its direct release into the environment can cause severe water pollution. Microbial fuel cells (MFCs) offer the possibility for converting organic matters in thin stillage into clean electricity. However, limited biofilm formation and conductivity are crucial bottlenecks in restricting the power harvest of MFCs. Here, to efficiently harvest electricity power from thin stillage of liquor industry, we adopted a modular engineering strategy to increase biofilm formation and conductivity of Shewanella oneidensis via enhancing the component biosynthesis of extracellular polymer substrates (EPS) matrix, regulating intracellular c-di-GMP level, and constructing of artificial hybrid system. The results showed that the constructed CNTs@CF-EnBF2 hybrid system with low charge-transfer resistance enabled a maximum output power density of 576.77 mW/m[2] in lactate-fed MFCs. Also, to evaluate the capability of harvesting electricity from actual wastewater, the CNTs@CF-EnBF2 system was employed to treat actual thin stillage, obtaining a maximum output power density of 495.86 mW/m[2], 3.3-fold higher than the wild-type strain. Our research suggested that engineering and regulating EPS biosynthesis effectively promoted bioelectricity harvest, providing a green and sustainable treatment strategy for thin stillage.}, } @article {pmid37658117, year = {2023}, author = {Kragh, KN and Tolker-Nielsen, T and Lichtenberg, M}, title = {The non-attached biofilm aggregate.}, journal = {Communications biology}, volume = {6}, number = {1}, pages = {898}, pmid = {37658117}, issn = {2399-3642}, support = {R250-2017-633//Lundbeckfonden (Lundbeck Foundation)/ ; }, abstract = {Biofilms have conventionally been perceived as dense bacterial masses on surfaces, following the five-step model of development. Initial biofilm research focused on surface-attached formations, but detached aggregates have received increasing attention in the past decade due to their pivotal role in chronic infections. Understanding their nature sparked fervent discussions in biofilm conferences and scientific literature. This review consolidates current insights on non-attached aggregates, offering examples of their occurrence in nature and diseases. We discuss their formation and dispersion mechanisms, resilience to antibiotics and immune-responses, drawing parallels to surface-attached biofilms. Moreover, we outline available in vitro models for studying non-attached aggregates.}, } @article {pmid37657329, year = {2023}, author = {Li, H and Cao, H and Li, T and He, Z and Zhao, J and Zhang, Y and Song, HL}, title = {Biofilm electrode reactor coupled manganese ore substrate up-flow microbial fuel cell-constructed wetland system: High removal efficiencies of antibiotic, zinc (II), and the corresponding antibiotic resistance genes.}, journal = {Journal of hazardous materials}, volume = {460}, number = {}, pages = {132394}, doi = {10.1016/j.jhazmat.2023.132394}, pmid = {37657329}, issn = {1873-3336}, abstract = {A coupled system comprised of a biofilm electrode reactor (BER) and a manganese ore substrate microbial fuel cell-constructed wetland (MFC-CW) system was used to remove co-exposed antibiotic and Zn (II), as well as simultaneously reduce copies of antibiotic resistance genes (ARGs) in the current study. In this system, BER primarily reduced the concentrations of antibiotics and Zn (II), and the effluent was used as the input to the MFC-CW, thereby providing electricity to BER. Co-exposure to a high concentration of Zn (II) decreased the relative abundances (RAs) of ARGs in the BER effluent, whereas the remaining sub-lethal concentration of Zn (II) increased the RAs of ARGs in the MFC-CW effluent. Even though the absolute copies of ARGs in the effluents increased during co-exposure, the total number of target ARG copies in the effluent of MFC-CW was significantly lower than that of BER. Moreover, BER pre-treatment eliminated most of Zn (II), which improved the electrical power generation characteristic of the MFC-CW unit. Correspondingly, the bacterial community and the ARGs hosts were analyzed to demonstrate the mechanism. In conclusion, the coupled system demonstrates significant potential to reduce antibiotics, Zn (II) and environmental risks posed by ARGs.}, } @article {pmid37656737, year = {2023}, author = {Duan, X and Jiang, L and Guo, M and Li, C}, title = {Isolation, characterization and application of a lytic phage vB_VspM_VS1 against Vibrio splendidus biofilm.}, journal = {PloS one}, volume = {18}, number = {9}, pages = {e0289895}, doi = {10.1371/journal.pone.0289895}, pmid = {37656737}, issn = {1932-6203}, abstract = {Vibrio splendidus is a common pathogen in the ocean that infects Apostichopus japonicus, Atlantic salmon and Crassostrea gigas, leading to a variety of diseases. In this study, a virulent phage vB_VspM_VS1, which infects V. splendidus, was isolated from aquaculture ponds in Dalian, China, and it belongs to the family Straboviridae in the order Caudoviricetes. vB_VspM_VS1 had an adsorption rate of 96% in 15 min, a latent period of 65 min, and a burst size of 140 ± 6 PFU/cell. The complete genome of phage vB_VspM_VS1 consists of a linear double-stranded DNA that is 248,270 bp in length with an average G + C content of 42.5% and 389 putative protein-coding genes; 116 genes have known functions. There are 4 tail fiber genes in the positive and negative strands of the phage vB_VspM_VS1 genome. The protein domain of the phage vB_VspM_VS1 tail fibers was obtained from the Protein Data Bank and the SMART (http://smart.embl.de) database. Bacterial challenge tests revealed that the growth of V. splendidus HS0 was apparently inhibited (OD600 < 0.01) in 12 h at an MOI of 10. In against biofilms, we also showed that the OD570 value of the vB_VspM_VS1-treated group (MOI = 1) decreased significantly to 0.04 ± 0.01 compared with that of the control group (0.48 ± 0.08) at 24 h. This study characterizes the genome of the phage vB_VspM_VS1 that infects the pathogenic bacterium V. splendidus of A. japonicus.}, } @article {pmid37655977, year = {2023}, author = {Seebach, E and Sonnenmoser, G and Kubatzky, KF}, title = {Staphylococcus aureus planktonic but not biofilm environment induces an IFN-β macrophage immune response via the STING/IRF3 pathway.}, journal = {Virulence}, volume = {}, number = {}, pages = {2254599}, doi = {10.1080/21505594.2023.2254599}, pmid = {37655977}, issn = {2150-5608}, abstract = {Chronic implant-related bone infections are a severe complication in orthopaedic surgery. Biofilm formation on the implant impairs the immune response, leading to bacterial persistence. In a previous study, we found that Staphylococcus aureus (SA) induced interferon regulatory factor 3 (IRF3) activation and Ifnb expression only in its planktonic form but not in the biofilm. The aim of this study was to clarify the role of the stimulator of interferon genes (STING) in this process. We treated RAW 264.7 macrophages with conditioned media (CM) generated from planktonic or biofilm cultured SA in combination with agonists or inhibitors of the cyclic GMP-AMP synthase (cGAS)/STING pathway. We further evaluated bacterial gene expression of planktonic and biofilm SA to identify potential mediators. STING inhibition resulted in the loss of IRF3 activation and Ifnb induction in SA planktonic CM, whereas STING activation induced an IRF3 dependent IFN-β response in SA biofilm CM. The expression levels of virulence-associated genes decreased during biofilm formation, but genes associated with cyclic dinucleotide (CDN) synthesis did not correlate with Ifnb induction. We further observed that cGAS contributed to Ifnb induction by SA planktonic CM, although cGAS activation was not sufficient to induce Ifnb expression in SA biofilm CM. Our data indicate that the different degrees of virulence associated with SA planktonic and biofilm environments result in an altered induction of the IRF3 mediated IFN-β response via the STING pathway. This finding suggests that the STING/IRF3/IFN-β axis is a potential candidate as an immunotherapeutic target for implant-related bone infections.}, } @article {pmid37655915, year = {2023}, author = {Zhang, M and Luo, X and Li, X and Zhang, T and Wu, F and Li, M and Lu, R and Zhang, Y}, title = {L-arabinose affects the growth, biofilm formation, motility, c-di-GMP metabolism, and global gene expression of Vibrio parahaemolyticus.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0010023}, doi = {10.1128/jb.00100-23}, pmid = {37655915}, issn = {1098-5530}, abstract = {The L-arabinose inducible pBAD vectors are commonly used to turn on and off the expression of specific genes in bacteria. The utilization of certain carbohydrates can influence bacterial growth, virulence factor production, and biofilm formation. Vibrio parahaemolyticus, the causative agent of seafood-associated gastroenteritis, can grow in media with L-arabinose as the sole carbon source. However, the effects of L-arabinose on V. parahaemolyticus physiology have not been investigated. In this study, we show that the growth rate, biofilm formation capacity, capsular polysaccharide production, motility, and c-di-GMP production of V. parahaemolyticus are negatively affected by L-arabinose. RNA-seq data revealed significant changes in the expression levels of 752 genes, accounting for approximately 15.6% of V. parahaemolyticus genes in the presence of L-arabinose. The affected genes included those associated with L-arabinose utilization, major virulence genes, known key biofilm-related genes, and numerous regulatory genes. In the majority of type III secretion system, two genes were upregulated in the presence of L-arabinose, whereas in those of type VI secretion system, two genes were downregulated. Ten putative c-di-GMP metabolism-associated genes were also significantly differentially expressed, which may account for the reduced c-di-GMP levels in the presence of L-arabinose. Most importantly, almost 40 putative regulators were significantly differentially expressed due to the induction by L-arabinose, indicating that the utilization of L-arabinose is strictly regulated by regulatory networks in V. parahaemolyticus. The findings increase the understanding of how L-arabinose affects the physiology of V. parahaemolyticus. Researchers should use caution when considering the use of L-arabinose inducible pBAD vectors in V. parahaemolyticus. IMPORTANCE The data in this study show that L-arabinose negatively affects the growth rate, biofilm formation, capsular polysaccharide production, motility, and c-di-GMP production of V. parahaemolyticus. The data also clarify the gene expression profiles of the bacterium in the presence of L-arabinose. Significantly differentially expressed genes in response to L-arabinose were involved in multiple cellular pathways, including L-arabinose utilization, virulence factor production, biofilm formation, motility, adaptation, and regulation. The collective findings indicate the significant impact of L-arabinose on the physiology of V. parahaemolyticus. There may be similar effects on other species of bacteria. Necessary controls should be established when pBAD vectors must be used for ectopic gene expression.}, } @article {pmid37655901, year = {2023}, author = {Toida, K and Kushida, W and Yamamoto, H and Yamamoto, K and Ishii, K and Uesaka, K and Kanaly, RA and Kutsuna, S and Ihara, K and Fujita, Y and Iwasaki, H}, title = {The GGDEF protein Dgc2 suppresses both motility and biofilm formation in the filamentous cyanobacterium Leptolyngbya boryana.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0483722}, doi = {10.1128/spectrum.04837-22}, pmid = {37655901}, issn = {2165-0497}, abstract = {Colony pattern formations of bacteria with motility manifest complicated morphological self-organization phenomena. Leptolyngbya boryana is a filamentous cyanobacterium, which has been used as a genetic model organism for studying metabolism including photosynthesis and nitrogen fixation. A widely used type strain [wild type (WT) in this article] of this species has not been reported to show any motile activity. However, we isolated a spontaneous mutant strain that shows active motility (gliding activity) to give rise to complicated colony patterns, including comet-like wandering clusters and disk-like rotating vortices on solid media. Whole-genome resequencing identified multiple mutations in the genome of the mutant strain. We confirmed that inactivation of the candidate gene dgc2 (LBDG_02920) in the WT background was sufficient to give rise to motility and morphologically complex colony patterns. This gene encodes a protein containing the GGDEF motif which is conserved at the catalytic domain of diguanylate cyclase (DGC). Although DGC has been reported to be involved in biofilm formation, the dgc2 mutant significantly facilitated biofilm formation, suggesting a role for the dgc2 gene in suppressing both gliding motility and biofilm formation. Thus, Leptolyngbya is expected to be an excellent genetic model for studying dynamic colony pattern formation and to provide novel insights into the role of DGC family genes in biofilm formation. IMPORTANCE Self-propelled bacteria often exhibit complex collective behaviors, such as formation of dense-moving clusters, which are exemplified by wandering comet-like and rotating disk-like colonies; however, the molecular details of how these structures are formed are scant. We found that a strain of the filamentous cyanobacterium Leptolyngbya deficient in the GGDEF protein gene dgc2 elicits motility and complex and dynamic colony pattern formation, including comet-like and disk-like clusters. Although c-di-GMP has been reported to activate biofilm formation in some bacterial species, disruption of dgc2 unexpectedly enhanced it, suggesting a novel role for this GGDEF protein for inhibiting both colony pattern formation and biofilm formation.}, } @article {pmid37655669, year = {2023}, author = {Xu, Q and Li, X and Jin, Y and Sun, L and Ding, X and Liang, L and Wang, L and Nan, K and Ji, J and Chen, H and Wang, B}, title = {Expression of concern: Bacterial self-defense antibiotics release from organic-inorganic hybrid multilayer films for long-term anti-adhesion and biofilm inhibition properties.}, journal = {Nanoscale}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3nr90178e}, pmid = {37655669}, issn = {2040-3372}, abstract = {Expression of concern for 'Bacterial self-defense antibiotics release from organic-inorganic hybrid multilayer films for long-term anti-adhesion and biofilm inhibition properties' by Qingwen Xu, Nanoscale, 2017, 9, 19245-19254, https://doi.org/10.1039/C7NR07106J.}, } @article {pmid37652259, year = {2023}, author = {Shaghayegh, G and Cooksley, C and Bouras, G and Houtak, G and Nepal, R and Psaltis, AJ and Wormald, PJ and Vreugde, S}, title = {S. aureus biofilm metabolic activity correlates positively with patients' eosinophil frequencies and disease severity in chronic rhinosinusitis.}, journal = {Microbes and infection}, volume = {}, number = {}, pages = {105213}, doi = {10.1016/j.micinf.2023.105213}, pmid = {37652259}, issn = {1769-714X}, abstract = {Chronic rhinosinusitis (CRS) is a persistent inflammation of the sinus mucosa. Recalcitrant CRS patients are unresponsive to medical and surgical interventions and often present with nasal polyps, tissue eosinophilia, and S. aureus dominant mucosal biofilms. However, S. aureus sinonasal mucosal colonisation occurs in the absence of inflammation, questioning the role of S. aureus in CRS pathogenesis. Here, we aimed to investigate the relationship between S. aureus biofilm metabolic activity and virulence genes, innate immune cells, and disease severity in CRS. Biospecimens, including sinonasal tissue and nasal swabs, and clinical datasets, including disease severity scores, were obtained from CRS patients and non-CRS controls. S. aureus isolates were grown into biofilms in vitro, characterised, and sequenced. The patients' innate immune response was evaluated using flow cytometry. S. aureus was isolated in 6/19 (31.58%) controls and 23/53 (43.40%) CRS patients of 72 recruited patients. We found increased S. aureus biofilm metabolic activity in relation to increased eosinophil cell frequencies and disease severity in recalcitrant CRS cases. Mast cell frequencies were higher in tissue samples of patients carrying S. aureus harbouring lukF.PV, sea, and fnbB genes. Patients with S. aureus harbouring lukF.PV and sdrE genes had more severe disease. This offers insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.}, } @article {pmid37652246, year = {2023}, author = {Khu, ST and Changchun, X and Wang, T}, title = {Effects of flow velocity on biofilm composition and microbial molecular ecological network in reclaimed water distribution systems.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {140010}, doi = {10.1016/j.chemosphere.2023.140010}, pmid = {37652246}, issn = {1879-1298}, abstract = {The existence of biofilm on the reclaimed water pipeline seriously affects the safety of water distribution. And the flow regimes in the pipeline play a crucial role in the growth of biofilms. In this study, the biofilm composition, surface topography and bacterial community were detected under eight levels of flow velocity in the range of 0.10-1.40 m s[-1]. The results showed that the dry weight, the concentration of extracellular protein and extracellular polysaccharide in the biofilm reached a dynamic stable period after 640 h. The biofilm composition and surface topography of biofilm were significantly different under the different flow regimes (laminar flow belongs to [0.10, 0.19] m s[-1], and turbulent flow belongs to [0.29, 1.40] m s[-1]). As the flow velocity range increases, the concentration of each component in the biofilm and the parameters of biofilm surface topography increased and then decreased. The flow velocity could be a strong environmental stimulus resulting in the succession of bacterial community in biofilm. As the flow velocity increased from 0.10 m s[-1] to 1.40 m s[-1], at the phylum level, the average relative abundance of Firmicutes mainly showed a trend of first increasing and then decreasing with the highest abundance value of 71.57% at 0.49 m s[-1]. The flow velocity increased from 0.10 m s[-1] to 0.49 m s[-1], a significant increase in microbial diversity could be detected. The increase in flow velocity promoted the proliferation of microorganisms, and the interaction between different microbial components was enhanced. At 0.49 m s[-1], the function of the biofilm is complex, and the ability to resist environmental stress is the strongest. This study can effectively improve the cognition depth of biofilms under the influence of flow velocity in the reclaimed water distribution systems, and provide an important theoretical support for the safe distribution of reclaimed water.}, } @article {pmid37652194, year = {2023}, author = {Brülisauer, L and Leon-Sampedro, R and Hall, AR}, title = {Clinical antibiotic-resistance plasmids have small effects on biofilm formation and population growth in Escherichia coli in vitro.}, journal = {Plasmid}, volume = {}, number = {}, pages = {102706}, doi = {10.1016/j.plasmid.2023.102706}, pmid = {37652194}, issn = {1095-9890}, abstract = {Antimicrobial resistance (AR) mechanisms encoded on plasmids can affect other phenotypic traits in bacteria, including biofilm formation. These effects may be important contributors to the spread of AR and the evolutionary success of plasmids, but it is not yet clear how common such effects are for clinical plasmids/bacteria, and how they vary among different plasmids and host strains. Here, we used a combinatorial approach to test the effects of clinical AR plasmids on biofilm formation and population growth in clinical and laboratory Escherichia coli strains. In most of the 25 plasmid-bacterium combinations tested, we observed no significant change in biofilm formation upon plasmid introduction, contrary to the notion that plasmids frequently alter biofilm formation. In a few cases we detected altered biofilm formation, and these effects were specific to particular plasmid-bacterium combinations. By contrast, we found a relatively strong effect of a chromosomal streptomycin-resistance mutation (in rpsL) on biofilm formation. Further supporting weak and host-strain-dependent effects of clinical plasmids on bacterial phenotypes in the combinations we tested, we found growth costs associated with plasmid carriage (measured in the absence of antibiotics) were moderate and varied among bacterial strains. These findings suggest some key clinical resistance plasmids cause only mild phenotypic disruption to their host bacteria, which may contribute to the persistence of plasmids in the absence of antibiotics.}, } @article {pmid37653441, year = {2023}, author = {McGlennen, M and Dieser, M and Foreman, CM and Warnat, S}, title = {Monitoring biofilm growth and dispersal in real-time with impedance biosensors.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jimb/kuad022}, pmid = {37653441}, issn = {1476-5535}, abstract = {Microbial biofilm contamination is a widespread problem that requires precise and prompt detection techniques to effectively control its growth. Microfabricated electrochemical impedance spectroscopy (EIS) biosensors offer promise as a tool for early biofilm detection and monitoring of elimination. This study utilized a custom flow cell system with integrated sensors to make real-time impedance measurements of biofilm growth under flow conditions, which were correlated with confocal laser scanning microscopy (CLSM) imaging. Biofilm growth on EIS biosensors in basic aqueous growth media (tryptic soy broth; TSB) and an oil-water emulsion (metalworking fluid; MWF) attenuated in a sigmoidal decay pattern, which lead to an ∼22 to 25% decrease in impedance after 24 hours. Subsequent treatment of established biofilms increased impedance by ∼14% and ∼41% in TSB and MWF, respectively. In the presence of Furanone C-30, a quorum sensing inhibitor (QSI), impedance remained unchanged from the initial time point for 18 hours in TSB and 72 hours in MWF. Biofilm changes enumerated from CLSM imaging corroborated impedance measurements, with treatment significantly reducing biofilm. Overall, these results support the application of microfabricated EIS biosensors for evaluating the growth and dispersal of biofilm in situ and demonstrate potential for use in industrial settings.}, } @article {pmid37653174, year = {2023}, author = {Goel, N and Zaidi, S and Khare, SK}, title = {Whole genome sequencing and functional analysis of a novel biofilm-eradicating strain Nocardiopsis lucentensis EMB25.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {11}, pages = {292}, pmid = {37653174}, issn = {1573-0972}, support = {MI01798//MHRD and IRD UNIT-IITD/ ; MI01798//MHRD and IRD UNIT-IITD/ ; MI01798//MHRD and IRD UNIT-IITD/ ; }, abstract = {The process of biofilm formation is intricate and multifaceted, requiring the individual cells to secrete extracellular polymeric substances (EPS) that subsequently aggregate and adhere to various surfaces. The issue of biofilms is a significant concern for public health due to the increased resistance of microorganisms associated with biofilms to antimicrobial agents. The current study describes the whole genome and corresponding functions of a biofilm inhibiting and eradicating actinobacteria isolate identified as Nocardiopsis lucentensis EMB25. The N. lucentensis EMB25 has 6.5 Mbp genome with 71.62% GC content. The genome analysis by BLAST Ring Image Generator (BRIG) revealed it to be closely related to Nocardiopsis dassonvillei NOCA502F. Interestingly, based on orthologous functional groups reflected by average nucleotide identity (ANI) analysis, it was 81.48% similar to N. arvandica DSM4527. Also, it produces lanthipeptides and linear azole(in)e-containing peptides (LAPs) akin to N. arvandica. The secondary metabolite search revealed the presence of major gene clusters involved in terpene, ectoine, siderophores, Lanthipeptides, RiPP-like, and T1PKS biosynthesis. After 24 h of treatment, the cell-free extract effectively eradicates the pre-existing biofilm of P. aeruginosa PseA. Also, the isolated bacteria exhibited antibacterial activity against MRSA, Staphylococcus aureus and Bacillus subtilis bacteria. Overall, this finding offers valuable insights into the identification of BGCs, which contain enzymes that play a role in the biosynthesis of natural products. Specifically, it sheds light on the functional aspects of these BGCs in relation to N. lucentensis.}, } @article {pmid37653076, year = {2023}, author = {Mukaddam, K and Astasov-Frauenhoffer, M and Fasler-Kan, E and Ruggiero, S and Alhawasli, F and Kisiel, M and Meyer, E and Köser, J and Bornstein, MM and Wagner, RS and Kühl, S}, title = {Piranha-etched titanium nanostructure reduces biofilm formation in vitro.}, journal = {Clinical oral investigations}, volume = {}, number = {}, pages = {}, pmid = {37653076}, issn = {1436-3771}, abstract = {OBJECTIVES: Nano-modified surfaces for dental implants may improve gingival fibroblast adhesion and antibacterial characteristics through cell-surface interactions. The present study investigated how a nanocavity titanium surface impacts the viability and adhesion of human gingival fibroblasts (HGF-1) and compared its response to Porphyromonas gingivalis with those of marketed implant surfaces.

MATERIAL AND METHODS: Commercial titanium and zirconia disks, namely, sandblasted and acid-etched titanium (SLA), sandblasted and acid-etched zirconia (ZLA), polished titanium (PT) and polished zirconia (ZrP), and nanostructured disks (NTDs) were tested. Polished titanium disks were etched with a 1:1 combination of 98% H2SO4 and 30% H2O2 (piranha etching) for 5 h at room temperature to produce the NTDs. Atomic force microscopy was used to measure the surface topography, roughness, adhesion force, and work of adhesion. MTT assays and immunofluorescence staining were used to examine cell viability and adhesion after incubation of HGF-1 cells on the disk surfaces. After incubation with P. gingivalis, conventional culture, live/dead staining, and SEM were used to determine the antibacterial properties of NTD, SLA, ZLA, PT, and ZrP.

RESULTS: Etching created nanocavities with 10-20-nm edge-to-edge diameters. Chemical etching increased the average surface roughness and decreased the surface adherence, while polishing and flattening of ZrP increased adhesion. However, only the NTDs inhibited biofilm formation and bacterial adherence. The NTDs showed antibacterial effects and P. gingivalis vitality reductions. The HGF-1 cells demonstrated greater viability on the NTDs compared to the controls.

CONCLUSION: Nanocavities with 10-20-nm edge-to-edge diameters on titanium disks hindered P. gingivalis adhesion and supported the adhesion of gingival fibroblasts when compared to the surfaces of currently marketed titanium or zirconia dental implants.

CLINICAL RELEVANCE: This study prepared an effective antibacterial nanoporous surface, assessed its effects against oral pathogens, and demonstrated that surface characteristics on a nanoscale level influenced oral pathogens and gingival fibroblasts.

CLINICAL TRIAL REGISTRATION: not applicable.}, } @article {pmid37651187, year = {2023}, author = {Hajfathalian, M and de Vries, CR and Hsu, JC and Amirshaghaghi, A and Dong, YC and Ren, Z and Liu, Y and Huang, Y and Li, Y and Knight, SA and Jonnalagadda, P and Zlitni, A and Grice, EA and Bollyky, PL and Koo, H and Cormode, DP}, title = {Theranostic gold-in-gold cage nanoparticles enable photothermal ablation and photoacoustic imaging in biofilm-associated infection models.}, journal = {The Journal of clinical investigation}, volume = {}, number = {}, pages = {}, doi = {10.1172/JCI168485}, pmid = {37651187}, issn = {1558-8238}, abstract = {Biofilms are structured communities of microbial cells embedded in a self-produced matrix of extracellular polymeric substances. Biofilms are associated with many health issues in humans, including chronic wound infections and tooth decay. Current antimicrobials are often incapable of disrupting the polymeric biofilm matrix and reaching the bacteria within. Alternative approaches are needed. Here, we describe a unique structure of dextran coated gold in a gold cage nanoparticle that enables photoacoustic and photothermal properties for biofilm detection and treatment. Activation of these nanoparticles with a near infrared laser can selectively detect and kill biofilm bacteria with precise spatial control and in a short timeframe. We observe a strong biocidal effect against both Streptococcus mutans and Staphylococcus aureus biofilms in mouse models of oral plaque and wound infections respectively. These effects were over 100 times greater than that seen with chlorhexidine, a conventional antimicrobial agent. Moreover, this approach did not adversely affect surrounding tissues. We conclude that photothermal ablation using theranostic nanoparticles is a rapid, precise, and non-toxic method to detect and treat biofilm-associated infections.}, } @article {pmid37651079, year = {2023}, author = {Ng, YS and Chan, DJC}, title = {Thermal Effect on Algae, Biofilm and Their Composition Towards Membrane Distillation Unit: A Mini-review.}, journal = {Molecular biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37651079}, issn = {1559-0305}, support = {Transdisciplinary Research Grant Scheme (TRGS) (TRGS/1/2018/USM/01/5/3)//Kementerian Pendidikan Malaysia/ ; }, abstract = {Membrane distillation (MD) has lower operating temperature and potential to recycle waste heat for desalination which catches much attention of the researchers in the recent years. However, the biofouling is still a challenging hurdle to be overcome for such applications. The microbial growth rate, secretion and biofilm formation are sensitive to heat. Membrane distillation is a thermally driven separation, so the increase of temperature in the seawater feed could influence the extent of biofouling on the unit parts. In this review, we present the effect of temperature on algal growth, the range of temperature the microbes, marine algae and planktons able to survive and the changes to those planktons once exceed the critical temperature. Thermal effect on the biofilm, its composition and properties are discussed as well, with association of the biofilm secreting microbes, but the study related to membrane distillation unit seems to be lacking and MD biofouling factors are not fully understood. Characterization of the algae, biofilm and EPS that govern biofouling are discussed. This information not only will help in designing future studies to fill up the knowledge gaps in biofouling of membrane distillation, but also to some extent, assist in pointing out possible fouling factors and predicting the degree of biofouling in the membrane distillation unit.}, } @article {pmid37650625, year = {2023}, author = {Arbour, CA and Nagar, R and Bernstein, HM and Ghosh, S and Al-Sammarraie, Y and Dorfmueller, HC and Ferguson, MAJ and Stanley-Wall, NR and Imperiali, B}, title = {Defining early steps in Bacillus subtilis biofilm biosynthesis.}, journal = {mBio}, volume = {}, number = {}, pages = {e0094823}, doi = {10.1128/mbio.00948-23}, pmid = {37650625}, issn = {2150-7511}, abstract = {The Bacillus subtilis extracellular biofilm matrix includes an exopolysaccharide (EPS) that is critical for the architecture and function of the community. To date, our understanding of the biosynthetic machinery and the molecular composition of the EPS of B. subtilis remains unclear and incomplete. This report presents synergistic biochemical and genetic studies built from a foundation of comparative sequence analyses targeted at elucidating the activities of the first two membrane-committed steps in the EPS biosynthetic pathway. By taking this approach, we determined the nucleotide sugar donor and lipid-linked acceptor substrates for the first two enzymes in the B. subtilis biofilm EPS biosynthetic pathway. EpsL catalyzes the first phosphoglycosyl transferase step using uridine diphosphate (UDP)-di-N-acetyl bacillosamine as phospho-sugar donor. EpsD is a predicted GT-B fold (GT4 family) retaining glycosyl transferase that catalyzes the second step in the pathway that utilizes the product of EpsL as an acceptor substrate and UDP-N-acetyl glucosamine as the sugar donor. Thus, the study defines the first two monosaccharides at the reducing end of the growing EPS unit. In doing so, we provide the first evidence of the presence of bacillosamine in an EPS synthesized by a Gram-positive bacterium. IMPORTANCE Biofilms are the communal way of life that microbes adopt to increase survival. Key to our ability to systematically promote or ablate biofilm formation is a detailed understanding of the biofilm matrix macromolecules. Here, we identify the first two essential steps in the Bacillus subtilis biofilm matrix exopolysaccharide (EPS) synthesis pathway. Together, our studies and approaches provide the foundation for the sequential characterization of the steps in EPS biosynthesis, using prior steps to enable chemoenzymatic synthesis of the undecaprenyl diphosphate-linked glycan substrates.}, } @article {pmid37650511, year = {2023}, author = {Nguyen, TP and Quyen Vo, TK and Nhu Tran, NV and Nhi Tran, NV}, title = {Biofilm reactors filled with Stick-bed Biofix and Swim-bed Biofringe biomass carriers in treating chitin production wastewater containing high salinity.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-26}, doi = {10.1080/09593330.2023.2254486}, pmid = {37650511}, issn = {1479-487X}, abstract = {AbstractThe production of chitin generates wastewater containing high content of organic compounds, nutrients, and salinity, thus a biofilm system including anaerobic-anoxic-aerobic bioreactors was employed. This study aims to evaluate the performance of Stick-bed Biofix and Swim-bed Biofringe added to bioreactors as a biomass carrier in order to enhance biomass concentration. The results indicated that the organic removal has been insignificantly affected by high salinity, the removal efficiency was obtained at 95 ± 2% corresponding to a rate of 5.78 ± 1.10 kg COD/m[3]/d. Otherwise, the nitrogen removal rate was achieved at around 0.45 ± 0.17 kg N/m[3]/d and strongly decreased to 0.24 ± 0.10 kg N/m[3]/d under high salinity of 18,000 mg/L and a high loading rate of 1.03 ± 0.10 kg N/m[3]/d. Phosphorus removal was obtained at 0.032-0.057 kg P/m[3]/d and decreased by 1.5 times when the salinity is over 10,000 mg/L although the influent load was strongly reduced by pre-treatment. Besides, the biofilm system can also remove around 50% of calcium ions which causes high salinity in chitin production wastewater.}, } @article {pmid37649801, year = {2023}, author = {Wijaya, M and Halleyantoro, R and Kalumpiu, JF}, title = {Biofilm: The invisible culprit in catheter-induced candidemia.}, journal = {AIMS microbiology}, volume = {9}, number = {3}, pages = {467-485}, pmid = {37649801}, issn = {2471-1888}, abstract = {Candidemia is the most common form of invasive fungal infection associated with several risk factors, and one of them is the use of medical devices, to which microbial biofilms can attach. Candidemia related to the use of peripheral intravascular and central venous catheters (CVC) is referred to as Candida catheter-related bloodstream infection, with more than 90% being related to CVC usage. The infection is associated with a higher morbidity and mortality rate than nosocomial bacterial infections. Candida spp. can protect themselves from the host immune system and antifungal drugs because of the biofilm structure, which is potentiated by the extracellular matrix (ECM). Candida albicans and Candida parapsilosis are the most pathogenic species often found to form biofilms associated with catheter usage. Biofilm formation of C. albicans includes four mechanisms: attachment, morphogenesis, maturation and dispersion. The biofilms formed between C. albicans and non-albicans spp. differ in ECM structure and composition and are associated with the persistence of colonization to infection for various catheter materials and antifungal resistance. Efforts to combat Candida spp. biofilm formation on catheters are still challenging because not all patients, especially those who are critically ill, can be recommended for catheter removal; also to be considered are the characteristics of the biofilm itself, which readily colonizes the permanent medical devices used. The limited choice and increasing systemic antifungal resistance also make treating it more difficult. Hence, alternative strategies have been developed to manage Candida biofilm. Current options for prevention or therapy in combination with systemic antifungal medications include lock therapy, catheter coating, natural peptide products and photodynamic inactivation.}, } @article {pmid37646916, year = {2023}, author = {Liu, H and Nio, S and Shen, Y}, title = {Sodium hypochlorite against Enterococcus faecalis biofilm in dentinal tubules: effect of concentration, temperature, and exposure time.}, journal = {Odontology}, volume = {}, number = {}, pages = {}, pmid = {37646916}, issn = {1618-1255}, abstract = {This study aimed to evaluate the effectiveness of two sodium hypochlorite concentrations at different exposure times and temperatures against Enterococcus faecalis biofilms of varying ages in human dentinal tubules. Dentin blocks were infected with E. faecalis for either 3 days or 3 weeks of incubation. Subsequently, the samples were exposed to sterile water, 2%, and 5.25% sodium hypochlorite for 3 and 10 min at 20 °C and 60 °C . Viability staining and confocal laser scanning microscopy were used to assess the proportion of killed bacteria in the dentinal tubules after exposure. There are no significant differences in the efficacy of E. faecalis killing between 2% sodium hypochlorite at 60 °C for various exposure times and 5.25% sodium hypochlorite at different temperatures or exposure times (P > 0.05). When both solutions were compared at the same temperatures with a 10-min exposure time, no significant differences in the effectiveness of E. faecalis killing between 2% and 5.25% sodium hypochlorite were observed (P > 0.05). To optimize the effectiveness of sodium hypochlorite in killing E. faecalis while minimizing potential damage to root dentin and soft tissue, clinicians should prioritize increasing the temperature or exposure time of sodium hypochlorite, rather than raising its concentration.}, } @article {pmid37646908, year = {2023}, author = {Martínez-Hernández, M and Reyes-Grajeda, JP and Hannig, M and Almaguer-Flores, A}, title = {Salivary pellicle modulates biofilm formation on titanium surfaces.}, journal = {Clinical oral investigations}, volume = {}, number = {}, pages = {}, pmid = {37646908}, issn = {1436-3771}, abstract = {OBJECTIVES: The present study aimed to evaluate the potential of the salivary pellicle (SP) formed on titanium (Ti) surfaces to modulate the formation of a biofilm composed of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis.

MATERIALS AND METHODS: Ti substrates were incubated for 2 h with a pool of saliva samples obtained from 10 systemically and periodontally healthy subjects. Enamel substrates were included as a biological reference. Scanning electron microscopy (SEM) and Raman spectroscopy analysis were used to analyze the formation of the salivary pellicle. After the SP formation, the surfaces were incubated for 12 h with a mix of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis. The number of bacterial cells attached to each surface was determined by the XTT assay while bacterial viability was analyzed by fluorescence microscopy using the LIVE/DEAD® BacLight[TM] kit.

RESULTS: The SEM and Raman spectroscopy analysis confirmed the presence of a salivary pellicle formed on the tested surfaces. Regarding the biofilm formation, the presence of the SP decreases the number of the bacterial cells detected in the test surfaces, compared with the uncover substrates. Even more, the SP-covered substrates showed similar bacterial counts in both Ti and enamel surfaces, meaning that the physicochemical differences of the substrates were less determinant than the presence of the SP. While on the SP-uncover substrates, differences in the bacterial adhesion patterns were directly related to the physicochemical nature of the substrates.

CONCLUSIONS: The salivary pellicle was the main modulator in the development of the biofilm consisting of representative oral bacteria on the Ti substrates.

CLINICAL RELEVANCE: The results of this study provide valuable information on the modulatory effect of the salivary pellicle on biofilm formation; such information allows us to understand better the events involved in the formation of oral biofilms on Ti dental implants.}, } @article {pmid37643702, year = {2023}, author = {Liu, X and Fang, L and Yan, X and Gardea-Torresdey, JL and Gao, Y and Zhou, X and Yan, B}, title = {Surface functional groups and biofilm formation on microplastics: Environmental implications.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166585}, doi = {10.1016/j.scitotenv.2023.166585}, pmid = {37643702}, issn = {1879-1026}, abstract = {Microplastics (MPs) contamination is becoming a significant environmental issue, as the widespread omnipresence of MPs can cause many adverse consequences for both ecological systems and humans. Contrary to what is commonly thought, the toxicity-inducing MPs are not the original pristine plastics; rather, they are completely transformed through various surface functional groups and aggressive biofilm formation on MPs via aging or weathering processes. Therefore, understanding the impacts of MPs' surface functional groups and biofilm formation on biogeochemical processes, such as environmental fate, transport, and toxicity, is crucial. In this review, we present a comprehensive summary of the distinctive impact that surface functional groups and biofilm formation of MPs have on their significant biogeochemical behavior in various environmental media, as well as their toxicity and biological effects. We place emphasis on the role of surface functional groups and biofilm formation as a means of influencing the biogeochemical processes of MPs. This includes their effects on pollutant fate and element cycling, which in turn impacts the aggregation, transport, and toxicity of MPs. Ultimately, future research studies and tactics are needed to improve our understanding of the biogeochemical processes that are influenced by the surface functional groups and biofilm formation of MPs.}, } @article {pmid37642488, year = {2023}, author = {Ramachandra, SS and Wright, P and Han, P and Abdal-Hay, A and Lee, RSB and Ivanovski, S}, title = {Evaluating models and assessment techniques for understanding oral biofilm complexity.}, journal = {MicrobiologyOpen}, volume = {12}, number = {4}, pages = {e1377}, doi = {10.1002/mbo3.1377}, pmid = {37642488}, issn = {2045-8827}, support = {//None/ ; }, abstract = {Oral biofilms are three-dimensional (3D) complex entities initiating dental diseases and have been evaluated extensively in the scientific literature using several biofilm models and assessment techniques. The list of biofilm models and assessment techniques may overwhelm a novice biofilm researcher. This narrative review aims to summarize the existing literature on biofilm models and assessment techniques, providing additional information on selecting an appropriate model and corresponding assessment techniques, which may be useful as a guide to the beginner biofilm investigator and as a refresher to experienced researchers. The review addresses previously established 2D models, outlining their advantages and limitations based on the growth environment, availability of nutrients, and the number of bacterial species, while also exploring novel 3D biofilm models. The growth of biofilms on clinically relevant 3D models, particularly melt electrowritten fibrous scaffolds, is discussed with a specific focus that has not been previously reported. Relevant studies on validated oral microcosm models that have recently gaining prominence are summarized. The review analyses the advantages and limitations of biofilm assessment methods, including colony forming unit culture, crystal violet, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt assays, confocal microscopy, fluorescence in situ hybridization, scanning electron microscopy, quantitative polymerase chain reaction, and next-generation sequencing. The use of more complex models with advanced assessment methodologies, subject to the availability of equipment/facilities, may help in developing clinically relevant biofilms and answering appropriate research questions.}, } @article {pmid37640222, year = {2023}, author = {Pan, H and Zhao, X and Zhou, X and Yan, H and Han, X and Wu, M and Chen, F}, title = {Research progress on the role of biofilm in heavy metals adsorption-desorption characteristics of microplastics: A review.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122448}, doi = {10.1016/j.envpol.2023.122448}, pmid = {37640222}, issn = {1873-6424}, abstract = {Microplastics (MPs) have been found to be widely distributed in aquatic environments, where they will interact with toxic heavy metals and result in more serious adverse effects on the aquatic environments and organisms. However, after entering the aquatic environments, MPs are quickly covered by biofilms, which significantly modify MPs properties and relevant heavy metals adsorption-desorption characteristics In order to better understand the adsorption behavior of heavy metals on biofilm developed MPs (BMPs), we comprehensively reviewed representative studies in this area. First, we summarized the formation process of biofilms on MPs. Subsequently, we reviewed the current understanding on the influence of biofilm formation on the properties of MPs and discussed the metal adsorption-desorption characteristics of MPs affected by these changes. Finally, based on the systematic literature review, some future research needs and strategies were proposed to further understand the interactions between MPs and heavy metals.}, } @article {pmid37639992, year = {2023}, author = {Wu, B and Ran, T and Liu, S and Li, Q and Cui, X and Zhou, Y}, title = {Biofilm bioactivity affects nitrogen metabolism in a push-flow microalgae-bacteria biofilm reactor during aeration-free greywater treatment.}, journal = {Water research}, volume = {244}, number = {}, pages = {120461}, doi = {10.1016/j.watres.2023.120461}, pmid = {37639992}, issn = {1879-2448}, abstract = {Non-aeration microalgae-bacteria biofilm has attracted increasing interest for its application in low cost wastewater treatment. However, it is unclear the quantified biofilm characteristics dynamics and how biofilm bioactivity affects performance and nitrogen metabolisms during wastewater treatment. In this work, a push-flow microalgae-bacteria biofilm reactor (PF-MBBfR) was developed for aeration-free greywater treatment. Comparatively, organic loading at 1.27 ± 0.10 kg COD/(m[3]⋅d) gave the highest biofilm concentration, density, specific oxygen generation (SOGR) and consumption rates (SOCR), and pollutants removal rates. Contributed to low residual linear alkylbenzene sulfonates and bioactivity, reactor downstream showed low bacteria and protein concentrations and SOCR (12.8 mg O2/g TSS·h), but high microalgae, carbohydrate, biofilm density, SOGR (49.4 mg O2/g TSS·h) and pollutants removal rates. Dissolved organic nitrogen (DON) showed higher molecular weight, CHONS and fraction with 4 atoms of N in reactor upstream. Most of nitrogen was fixed to newly synthesized biomass during assimilation process by related functional enzymes, minor contributed to denitrification due to low N2 emission. High nitrogen assimilation by microalgae showed high SOGR, which favored efficient multiple pollutants removal and reduced DON emission. Our findings favor the practical application of PF-MBBfR based on biofilm bioactivity, enhancing efficiency and reducing DON emission for low- energy-input wastewater treatment.}, } @article {pmid37639210, year = {2023}, author = {Shen, Y and Bai, X and Wang, J and Zhou, X and Meng, R and Guo, N}, title = {Inhibitory Effect of Non-Saccharomyces Starmerella bacillaris CC-PT4 Isolated from Grape on MRSA Growth and Biofilm.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {37639210}, issn = {1867-1314}, support = {No.31772082//National Natural Science Foundation of China/ ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious pathogen with biofilm-forming and drug-resistant properties that make it difficult to eradicate. In this study, the inhibition of MRSA (ATCC 43300) by Starmerella bacillaris CC-PT4 (CGMCC No. 23573) was evaluated. The results showed that the inhibition of MRSA growth and biofilm was caused by S. bacillaris CC-PT4 cell-free supernatant (CFS). The CFS of S. bacillaris CC PT4 at different times can effectively inhibit the formation of MRSA biofilm, remove the preformed biofilm, and down-regulate the related genes that promote the formation of biofilm. Afterwards, untargeted metabolomics was performed to analyze the CFS of S. bacillaris CC-PT4. Several molecules with antibacterial and inhibitory biofilm effects from the CFS were found, one of which, 2-amino-1-phenylethanol (APE), has not been reported to have antiMRSA ability before. In this study, molecular docking analysis and in vitro experiments were used to verify the function of APE to inhibit MRSA. These results indicate that S. bacillaris CC-PT4 CFS can effectively inhibit MRSA which has potential application value in controlling MRSA.}, } @article {pmid37638766, year = {2023}, author = {Díaz-Rullo, J and González-Pastor, JE}, title = {tRNA queuosine modification is involved in biofilm formation and virulence in bacteria.}, journal = {Nucleic acids research}, volume = {}, number = {}, pages = {}, doi = {10.1093/nar/gkad667}, pmid = {37638766}, issn = {1362-4962}, support = {//Universidad de Alcalá/ ; FPU18/03583//Spanish Ministry of Universities/ ; 10.13039/501100011033//Spanish Ministry of Science and Innovation/ ; PID2021-126114NB-C43//ERDF/ ; 101081957//European Commission/ ; }, abstract = {tRNA modifications are crucial for fine-tuning of protein translation. Queuosine (Q) modification of tRNAs is thought to modulate the translation rate of NAU codons, but its physiological role remains elusive. Therefore, we hypothesize that Q-tRNAs control those physiological processes involving NAU codon-enriched genes (Q-genes). Here, we report a novel bioinformatic strategy to predict Q-genes, revealing a widespread enrichment in functions, especially those related to biofilm formation and virulence in bacteria, and particularly in human pathogens. Indeed, we experimentally verified that these processes were significantly affected by altering the degree of tRNA Q-modification in different model bacteria, representing the first report of a general mechanism controlling biofilm formation and virulence in Gram-positive and Gram-negative bacteria possibly through the coordination of the expression of functionally related genes. Furthermore, we propose that changes in Q availability in a microbiome would affect its functionality. Our findings open the door to the control of bacterial infections and biofilm formation by inhibition of tRNA Q-modification.}, } @article {pmid37636622, year = {2023}, author = {Kanagamuthu, P and Santhipalayam Ranganathan, K}, title = {Bacteriological Profile of Chronic Rhinosinusitis and Adenotonsillitis: Evaluating the Role of Biofilm Production and Multidrug Resistance.}, journal = {Indian journal of otolaryngology and head and neck surgery : official publication of the Association of Otolaryngologists of India}, volume = {75}, number = {3}, pages = {2207-2216}, pmid = {37636622}, issn = {2231-3796}, abstract = {There is significant evidence that the etiology of chronic otorhinolaryngology infections such as chronic rhinosinusitis, adenotonsillitis, and otitis media depends on biofilms. As biofilm-forming bacteria can be resistant to the immune system, antibiotics, and other treatments, biofilm infections are often chronic. To identify the genus and species of the clinical isolates obtained from the swabs collected from the patients with chronic infections of the nasal and paranasal sinus, nasopharynx, and oropharynx and to evaluate phenotypic and genotypic methods for the detection of biofilms and antimicrobial resistance among the isolated organisms. A total of 100 patients with chronic rhinosinusitis and adenotonsillitis participated in this study. Various clinical samples from the nasal cavity, nasopharynx, and oropharynx were obtained and subjected to microbiological analysis and biofilm-forming capacity by three methods: tube methods, Congo red staining, and microtiter plate method. The various specific genes were amplified by polymerase chain reaction. The amplified gene products were separated by gel electrophoresis. This was a prospective cohort study conducted on a total of 100 patients with chronic rhinosinusitis and adenotonsillitis. The age of the study participants was between 7 and 53 years with a mean age of 29.22 ± 15.03. This study included 54 (54%) nasal tissue samples and 46 (46%) adenotonsillar tissue. The frequently cultured organisms are coagulase-negative staphylococci (17%), E. coli (10%), Citrobacter (10%), and Klebsiella (7%). Staphylococcus aureus (4), and Methicillin-resistant Staphylococcus aureus (3) produced strong biofilm. Acenobacter (3), Citrobacter (4), and E. coli (4) showed moderate biofilm production. Coagulase-negative Staphylococcus aureus (11), E. coli (6), and Klebsiella (7) showed weak biofilm formation. Citrobacter (6), and Coagulase negative Staphylococcus aureus (6) were negative for biofilm production. Staphylococcus aureus expressed mecA gene (3) and Panton-Valentine Leukocidin gene (2), Pseudomonas expressed mucA gene (2), Citrobacter expressed blaCARB-2 (4) qnrA gene (2), E. coli expressed bla SHV (2) and bla TEM1 gene (2) and Klebsiella expressed Kfu (2) and uge (1). Acenobacter was negative for blaIMP1, blaVIM2 genes. This study adds to the information on the common pathogens-forming biofilms in various nasal pathologies and adenotonsillitis. The knowledge that a particular organism has a higher biofilm-forming capacity will help to sensitize the physician that factors such as biofilms may be at play and take appropriate measures.}, } @article {pmid37635995, year = {2023}, author = {Han, H and Chen, L and Liang, S and Lü, J and Wu, Y and Wang, X and Xu, F and Ge, L and Xiao, L}, title = {PLA-HPG based coating enhanced anti-biofilm and wound healing of Shikonin in MRSA-infected burn wound.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1243525}, pmid = {37635995}, issn = {2296-4185}, abstract = {Burn wounds are susceptible to bacterial infections, including Methicillin-resistant Staphylococcus aureus (MRSA), which typically form biofilms and exhibit drug resistance. They also have specific feature of abundant exudate, necessitating frequent drug administration. Shikonin (SKN) has been reported to reverse MRSA drug resistance and possesses anti-biofilm and wound healing properties, however, it suffers from drawbacks of low solubility and instability. In this study, we developed PLA-HPG based bioadhesive nanoparticles SKN/BNP, which demonstrated a drug loading capacity of about 3.6%, and exhibited sustained-release behavior of SKN. The aldehyde groups present on the surface of BNP improved the local adhesion of SKN/BNP both in vitro and in vivo, thereby reducing the frequency of drug dosing in exudate-rich burn wounds. BNP alone enhanced proliferation and migration of the fibroblast, while SKN/BNP promoted fibroblast proliferation and migration as well as angiogenesis. Due to its bioadhesive property, BNP directly interacted with biofilm and enhanced the efficacy of SKN against MRSA biofilm in vitro. In a mouse model of MRSA-infected burn wounds, SKN/BNP demonstrated improved anti-biofilm and wound healing efficiency. Overall, our findings suggest that SKN/BNP holds great promise as a novel and effective treatment option for clinical applications in MRSA-infected burn wounds.}, } @article {pmid37634478, year = {2023}, author = {Kalia, VC and Patel, SKS and Lee, JK}, title = {Bacterial biofilm inhibitors: An overview.}, journal = {Ecotoxicology and environmental safety}, volume = {264}, number = {}, pages = {115389}, doi = {10.1016/j.ecoenv.2023.115389}, pmid = {37634478}, issn = {1090-2414}, abstract = {Bacteria that cause infectious diseases adopt biofilms as one of their most prevalent lifestyles. Biofilms enable bacteria to tolerate environmental stress and evade antibacterial agents. This bacterial defense mechanism has rendered the use of antibiotics ineffective for the treatment of infectious diseases. However, many highly drug-resistant microbes have rapidly emerged owing to such treatments. Different signaling mechanisms regulate bacterial biofilm formation, including cyclic dinucleotide (c-di-GMP), small non-coding RNAs, and quorum sensing (QS). A cell density-dependent phenomenon, QS is associated with c-di-GMP (a global messenger), which regulates gene expression related to adhesion, extracellular matrix production, the transition from the planktonic to biofilm stage, stability, pathogenicity, virulence, and acquisition of nutrients. The article aims to provide information on inhibiting biofilm formation and disintegrating mature/preformed biofilms. This treatment enables antimicrobials to target the free-living/exposed bacterial cells at lower concentrations than those needed to treat bacteria within the biofilm. Therefore, a complementary action of antibiofilm and antimicrobial agents can be a robust strategic approach to dealing with infectious diseases. Taken together, these molecules have broad implications for human health.}, } @article {pmid37634456, year = {2023}, author = {Huang, Y and Wang, J and Sun, Y and Zeng, W and Xia, A and Zhu, X and Zhu, X and Liao, Q}, title = {Non-immersed zigzag microalgae biofilm overcoming high turbidity and ammonia of wastewater for muti-pollutants bio-purification.}, journal = {Water research}, volume = {244}, number = {}, pages = {120499}, doi = {10.1016/j.watres.2023.120499}, pmid = {37634456}, issn = {1879-2448}, abstract = {Biological treatment that utilizes microalgae technology has demonstrated outstanding efficacy in the wastewater purification and nutrients recovery. However, the high turbidity of the digested piggery wastewater (DPW) leads to serious light attenuation and the culture mode of suspended microalgae results in a huge landing area. Thus, to overcome light attenuation in DPW, a non-immersed titled zigzag microalgae biofilm was constructed by attaching it onto a porous cotton cloth. As a result, the light could directly irradiate microalgae biofilm that attached on both sides of the cotton cloth, and the microalgal biofilm area was up to 6 m[2] per bioreactor landing area. When the non-immersed zigzag microalgae biofilm bioreactor (N-Z-MBP) was used to treat wastewater with an ammonia nitrogen (NH4[+]-N) concentration of 362 mg L[-1], the NH4[+]-N was completely removed in just 5 days and the maximum growth rate of microalgae biofilm reached 7.02 g m[-2] d[-1]. After 21 days of long-term sequencing batch operation for the N-Z-MBP, the biomass density of the biofilm reached 52 g m[-2] and remained at this high value for the next 14 days. Most importantly, during the 35 days' running, the NH4[+] -N maximum removal rate of single batch reached up to 65 mg L[-1] d[-1] and its concentration in the effluent was always below the discharge standard value (80 mg L[-1] form GB18596-2001 of China) and total phosphorus was completely removed in each batch. Furthermore, the biomass concentration of microalgae cells in the effluent of the N-Z-MBP was almost zero, indicating that the non-submerged biofilm achieved in situ separation of microalgae from the wastewater. This work suggests that the N-Z-MBP can effectively purify DPW over a long period, providing a possible strategy to treat wastewater with high ammonia nitrogen and high turbidity.}, } @article {pmid37634214, year = {2023}, author = {Abdurahman, MA and Durukan, İ and Dinçer, T and Pektaş, S and Karataş, E and Kiliç, AO}, title = {Staphylococcus aureus Bacteriophage 52 Endolysin Exhibits Anti-Biofilm and Broad Antibacterial Activity Against Gram-Positive Bacteria.}, journal = {The protein journal}, volume = {}, number = {}, pages = {}, pmid = {37634214}, issn = {1875-8355}, support = {TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; TDK-2015-5340//Karadeniz Teknik Üniversitesi/ ; }, abstract = {Bacteriophage endolysins have been shown to hold great promise as new antibacterial agents for animal and human health in food preservation. In the present study, endolysin from Staphylococcus aureus subsp. aureus ATCC 27692-B1 bacteriophage 52 (LysSA52) was cloned, expressed, and characterized for its antimicrobial properties. Following DNA extraction from bacteriophage 52, a 1446-bp DNA fragment containing the endolysin gene (lysSA52) was obtained by PCR amplification and cloned into pET SUMO expression vector. The positive clone was validated by sequencing and open-reading frame analysis. The LysSA52 sequence shared high homology with staphylococcal phage endolysins of the SA12, SA13, and DSW2 phages and others. The cloned lysSA52 gene encoding 481 amino acids endolysin was expressed in Escherichia coli BL21 with a calculated molecular mass of 66 kDa (LysSA52). This recombinant endolysin LysSA52 exhibited lytic activity against 8 of 10 Gram-positive bacteria via agar spot-on lawn antimicrobial assay, including methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Streptococcus pneumonia, Streptococcus pyogenes, Enterococcus faecium, Enterococcus faecalis, and Bacillus atrophaeus. In addition, the 0.50 mg/mL, LysSA52 endolysins reduced about 60% of the biofilms of S. aureus and S. epidermidis established on a microtiter plate in 12 h treatment. The data from this study indicate that LysSA52 endolysin could be used as an antibacterial protein to prevent and treat infections caused by staphylococci and several other Gram-positive pathogenic bacteria irrespective of their antibiotic resistance.}, } @article {pmid37633400, year = {2023}, author = {Wei, J and Huang, X and Wang, H and Wang, F and Liu, X and Yan, Y and Qu, Y}, title = {Insight into biofilm formation of wastewater treatment processes: Nitrogen removal performance and biological mechanisms.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166550}, doi = {10.1016/j.scitotenv.2023.166550}, pmid = {37633400}, issn = {1879-1026}, abstract = {Biofilm formation affects biological nitrogen (N) removal, and a sequencing batch biofilm reactor (SBBR) was set up to evaluate the changes in N removal and microbial characteristics during biofilm formation. The results indicated that the average effluent concentration of chemical oxygen demand (COD), ammonia nitrogen (NH4[+]-N) and total nitrogen (TN) in the SBBR were 27.48, 1.41, and 13.52 mg L[-1], respectively after biofilm formation. Furthermore, this process increased microbial richness, but reduced microbial diversity. Patescibacteria, Proteobacteria, and Bacteroides were the dominant phyla that did not change after biofilm formation. After biofilm formation, Firmicutes was eliminated while Spirochaetes involved in the interspecies relationship. Biofilm increased the nitrification and denitrification relating coding genes abundance (hao, narG, narZ, nxrA, narH, narY, nxrB, napA, napB, norB, norC and nosZ), and enhanced the processes of N respiration and denitrification, carbohydrate metabolism, amino acid metabolism and membrane transport. Meanwhile, correlation analysis between genera and transcriptome reflected that Zooglea, Micropruina, Aeromonas and Tessaracoccus played essential roles in biofilm formation and N removal. The key enzyme abundance of EC:1.7.99.1, EC:1.7.2.4, and EC:1.1.1.42 of N and tricarboxylic acid (TCA) cycle increased after biofilm formation. This study can reveal the effect of biofilm formation on biological N removal and provide a theoretical foundation for the application of biofilm process.}, } @article {pmid37632199, year = {2023}, author = {Escobar, MR and Lepek, VC and Basile, LA}, title = {Influence of cyclic di-GMP metabolism to T3SS expression, biofilm formation and symbiosis efficiency in Mesorhizobium japonicum MAFF303099.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnad087}, pmid = {37632199}, issn = {1574-6968}, abstract = {A link between the T3SS and inhibition of swimming motility by the transcriptional regulator TtsI in Mesorhizobium japonicum MAFF303099 has been previously reported. Here, we show that mutants in T3SS components display impaired biofilm formation capacity, indicating that a functional T3SS, or at least pili formation, is required for this process. As a first approach to the cdiG regulation network in this bacterium, we started a study of the second messenger cdiG by overexpressing or by deleting some genes encoding cdiG metabolizing enzymes. Overexpression of two putative PDEs as well as deletion of various DGCs led to reduced biofilm formation on glass tubes. Mutation of dgc9509 also affected negatively the nodulation and symbiosis efficiency on Lotus plants, which can be related to the observed reduction in adhesion to plant roots. Results from transcriptional nopX- and ttsI-promoter-lacZ fusions suggested that cdiG negatively regulates T3SS expression in M. japonicum MAFF303099.}, } @article {pmid37631982, year = {2023}, author = {Li, X and Li, X and Zhang, H and Kan, B and Fan, F}, title = {VP3 Phage Combined with High Salt Promotes the Lysis of Biofilm-Associated Vibrio cholerae.}, journal = {Viruses}, volume = {15}, number = {8}, pages = {}, doi = {10.3390/v15081639}, pmid = {37631982}, issn = {1999-4915}, support = {2021YFC2300304//National Key Research and Development Program of China/ ; 19008022271//Research Foundation for Youth Scholars of Beijing Technology and Business University/ ; }, abstract = {Cholera, caused by pathogenic Vibrio cholerae, poses a significant public health risk through water and food transmission. Biofilm-associated V. cholerae plays a crucial role in seasonal cholera outbreaks as both a reservoir in aquatic environments and a direct source of human infection. Although VP3, a lytic phage, shows promise in eliminating planktonic V. cholerae from the aquatic environment, its effectiveness against biofilm-associated V. cholerae is limited. To address this limitation, our proposed approach aims to enhance the efficacy of VP3 in eliminating biofilm-associated V. cholerae by augmenting the availability of phage receptors on the surface of Vibrio cholerae. TolC is a receptor of VP3 and a salt efflux pump present in many bacteria. In this study, we employed NaCl as an enhancer to stimulate TolC expression and observed a significant enhancement of TolC expression in both planktonic and biofilm cells of V. cholerae. This enhancement led to improved adsorption of VP3. Importantly, our findings provide strong evidence that high salt concentrations combined with VP3 significantly improve the elimination of biofilm-associated V. cholerae. This approach offers a potential strategy to eliminate biofilm-formation bacteria by enhancing phage-host interaction.}, } @article {pmid37631320, year = {2023}, author = {Kauser, A and Parisini, E and Suarato, G and Castagna, R}, title = {Light-Based Anti-Biofilm and Antibacterial Strategies.}, journal = {Pharmaceutics}, volume = {15}, number = {8}, pages = {}, doi = {10.3390/pharmaceutics15082106}, pmid = {37631320}, issn = {1999-4923}, support = {No.1.1.1.5/21/A/003//European Regional Development Fund/ ; No. 1.1.1.5/19/A/004//European Regional Development Fund/ ; }, abstract = {Biofilm formation and antimicrobial resistance pose significant challenges not only in clinical settings (i.e., implant-associated infections, endocarditis, and urinary tract infections) but also in industrial settings and in the environment, where the spreading of antibiotic-resistant bacteria is on the rise. Indeed, developing effective strategies to prevent biofilm formation and treat infections will be one of the major global challenges in the next few years. As traditional pharmacological treatments are becoming inadequate to curb this problem, a constant commitment to the exploration of novel therapeutic strategies is necessary. Light-triggered therapies have emerged as promising alternatives to traditional approaches due to their non-invasive nature, precise spatial and temporal control, and potential multifunctional properties. Here, we provide a comprehensive overview of the different biofilm formation stages and the molecular mechanism of biofilm disruption, with a major focus on the quorum sensing machinery. Moreover, we highlight the principal guidelines for the development of light-responsive materials and photosensitive compounds. The synergistic effects of combining light-triggered therapies with conventional treatments are also discussed. Through elegant molecular and material design solutions, remarkable results have been achieved in the fight against biofilm formation and antibacterial resistance. However, further research and development in this field are essential to optimize therapeutic strategies and translate them into clinical and industrial applications, ultimately addressing the global challenges posed by biofilm and antimicrobial resistance.}, } @article {pmid37630662, year = {2023}, author = {Terlep, S and Dogsa, I and Pajk, F and Stopar, D}, title = {Biofilm Removal from In Vitro Narrow Geometries Using Single and Dual Pulse Er:YAG Laser Photoacoustic Irrigation.}, journal = {Microorganisms}, volume = {11}, number = {8}, pages = {}, doi = {10.3390/microorganisms11082102}, pmid = {37630662}, issn = {2076-2607}, support = {L7-3186//Slovenian Research Agency/ ; }, abstract = {The disinfection and removal of biofilm from titanium dental implants remains a great challenge in oral medicine. Here we present results of novel photoacoustic irrigation laser modalities for biofilm removal in model geometries mimicking the peri-implant pocket. The efficacy of single pulse (Er:YAG-SSP) and dual pulse (Er:YAG-AutoSWEEPS) photoacoustic irrigation modalities were determined for Enterococcus faecalis biofilm decontamination from titanium surfaces in narrow cylindrical and square gap geometries. The density of bacteria as well as the number of live bacteria were determined prior and after different photoacoustic treatments. Both SSP and AutoSWEEPS photoacoustic irrigation techniques removed at least 92% of biofilm bacteria during the 10 s photoacoustic treatment. The effectiveness of cleaning was better in the narrow square gap geometry compared to the cylindrical geometry. The dual pulse Er:YAG-AutoSWEEPS photoacoustic irrigation showed better results compared to SSP modality. No chemical adjuvants were needed to boost the effectiveness of the photoacoustic irrigation in the saline solution. The results imply that photoacoustic irrigation is an efficient cleaning method for debridement and decontamination in narrow geometries and should be considered as a new therapeutic option for the treatment of peri-implant diseases.}, } @article {pmid37630565, year = {2023}, author = {Gao, Y and Chen, K and Lin, R and Xu, X and Xu, F and Lin, Q and Hu, Y and Zhang, H and Zhang, J and Liao, M and Qu, X}, title = {High Levels of Antibiotic Resistance in MDR-Strong Biofilm-Forming Salmonella Typhimurium ST34 in Southern China.}, journal = {Microorganisms}, volume = {11}, number = {8}, pages = {}, doi = {10.3390/microorganisms11082005}, pmid = {37630565}, issn = {2076-2607}, support = {31972762//National Natural Science Foundation of China/ ; 2022YFD1800400//National Key R&D Program of China/ ; 2017A020208055//Province Science and Technology of Guangdong Research Project/ ; 2019B020217002//Guangdong Key S & T Program from Department of Science and Technology of Guangdong Province/ ; 61626817, SA1703162//Walmart Foundation Supported by Walmart Food Safety Collaboration Center/ ; cARS-41- G16//National Broiler Industry Technology System Project/ ; R2020PY-JC001//Scientific Innovation Strategy-construction of High Level Academy of Agriculture Sci-ence-Prominent Talents/ ; 2022SDZG02//Open Competition Program of Top Ten Critical Priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province/ ; }, abstract = {Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium) is an important zoonotic pathogen with important public health significance. To understand S. typhimurium's epidemiological characteristics in China, multi-locus sequence typing, biofilm-forming ability, antimicrobial susceptibility testing, and resistant genes of isolates from different regions and sources (human, food) were investigated. Among them, ST34 accounted for 82.4% (243/295), with ST19 ranking second (15.9%; 47/295). ST34 exhibited higher resistance levels than ST19 (p < 0.05). All colistin, carbapenem, and ciprofloxacin-resistant strains were ST34, as were most cephalosporin-resistant strains (88.9%; 32/36). Overall, 91.4% (222/243) ST34 isolates were shown to have multidrug resistance (MDR), while 53.2% (25/47) ST19 isolates were (p < 0.05). Notably, 97.8% (45/46) of the MDR-ACSSuT (resistance to Ampicillin, Chloramphenicol, Streptomycin, Sulfamethoxazole, and Tetracycline) isolates were ST34, among which 69.6% (32/46) of ST34 isolates were of human origin, while 30.4% (14/46) were derived from food (p < 0.05). Moreover, 88.48% (215/243) ST34 showed moderate to strong biofilm-forming ability compared with 10.9% (5/46) ST19 isolates (p < 0.01). This study revealed the emergence of high-level antibiotic resistance S. typhimurium ST34 with strong biofilm-forming ability, posing concerns for public health safety.}, } @article {pmid37630542, year = {2023}, author = {Huang, X and Laird, CG and Riley, PP and Wen, ZT}, title = {Impacts of a DUF2207 Family Protein on Streptococcus mutans Stress Tolerance Responses and Biofilm Formation.}, journal = {Microorganisms}, volume = {11}, number = {8}, pages = {}, doi = {10.3390/microorganisms11081982}, pmid = {37630542}, issn = {2076-2607}, support = {DE019452//National Institute of Health/ ; }, abstract = {Locus SMU.243 in Streptococcus mutans was annotated as a member of the DUF2207 family proteins highly conserved in all bacteria but with unknown function. To investigate its role in S. mutans physiology, a SMU.243-deficient mutant was constructed using allelic exchange mutagenesis, and the impacts of SMU.243 deletion on bacterial growth, stress tolerance response, and biofilm formation were analyzed. Compared to the wild-type UA159, S. mutans lacking SMU.243 displayed a reduced growth rate and a reduced overnight culture density (p < 0.01) when grown at low pH and in the presence of methyl viologen. Relative to the parent strain, the deficient mutant also had a reduced survival rate following incubation in a buffer of pH 2.8 (p < 0.01) and in a buffer containing hydrogen peroxide at 58 mM after 60 min (p < 0.001) and had a reduced capacity in biofilm formation especially in the presence of sucrose (p < 0.01). To study any ensuing functional/phenotypical links between SMU.243 and uppP, which is located immediately downstream of SMU.243 and encodes an undecaprenyl pyrophosphate phosphatase involved in recycling of carrier lipid undecaprenyl phosphate, a uppP deficient mutant was generated using allelic exchange mutagenesis. Unlike the SMU.243 mutant, deletion of uppP affected cell envelope biogenesis and caused major increases in susceptibility to bacitracin. In addition, two variant morphological mutants, one forming rough colonies and the other forming mucoid, smooth colonies, also emerged following the deletion of uppP. The results suggest that the SMU.243-encoded protein of the DUF2207 family in S. mutans plays an important role in stress tolerance response and biofilm formation, but unlike the downstream uppP, does not seem to be involved in cell envelope biogenesis, although the exact roles in S. mutans' physiology awaits further investigation.}, } @article {pmid37630499, year = {2023}, author = {N'Tcha, C and Sina, H and Bourobou, DN and Hoteyi, SMI and Boya, B and Agnimonhan, R and Mavoungou, JF and Adjanohoun, A and Babalola, OO and Baba-Moussa, L}, title = {Resistance and Biofilm Production Profile of Potential Isolated from Kpètè-Kpètè Used to Produce Traditional Fermented Beer.}, journal = {Microorganisms}, volume = {11}, number = {8}, pages = {}, doi = {10.3390/microorganisms11081939}, pmid = {37630499}, issn = {2076-2607}, abstract = {This study aimed to characterize the pathogenicity of bacteria isolated from the starter of two traditional beers produced and consumed in Benin. After standard microbial identification, species were identified by specific biochemical tests such as catalase, coagulase, and API 20 E. Antibiotic sensitivity was tested according to the French Society of Microbiology Antibiogram Committee. The crystal violet microplate technique evaluated the biofilm production and conventional PCR was used to identify genes encoding virulence and macrolide resistance. According to our data, the traditional starter known as kpètè-kpètè that is used to produce beer is contaminated by Enterobacteriaceae and staphylococci species. Thus, 28.43% of the isolated bacteria were coagulase-negative staphylococci (CNS), and 10.93% coagulase-positive staphylococci (CPS). Six species such as Klebsiella terrigena (1.38%), Enterobacter aerogens (4.14%), Providencia rettgeri (5.51%), Chryseomonas luteola (6.89%), Serratia rubidae (15.16%), and Enterobacter cloacae (27.56%) were identified among Enterobacteriaceae. Those bacterial strains are multi-resistant to conventional antibiotics. The hight capability of produced biofilms was recorded with Enterobacter aerogens, Klebsiella terrigena (100%), Providencia rettgeri (75%), and Staphylococcus spp (60%). Enterobacter cloacae (4%) and coagulase-negative Staphylococcus (5.55%) harbor the macrolide resistance gene. For other strains, these genes were not detected. Foods contaminated with bacteria resistant to antibiotics and carrying a virulence gene could constitute a potential public health problem. There is a need to increase awareness campaigns on hygiene rules in preparing and selling these traditional beers.}, } @article {pmid37630469, year = {2023}, author = {Kaleva, MD and Ilieva, Y and Zaharieva, MM and Dimitrova, L and Kim, TC and Tsvetkova, I and Georgiev, Y and Orozova, P and Nedev, K and Najdenski, H}, title = {Antimicrobial Resistance and Biofilm Formation of Escherichia coli Isolated from Pig Farms and Surroundings in Bulgaria.}, journal = {Microorganisms}, volume = {11}, number = {8}, pages = {}, doi = {10.3390/microorganisms11081909}, pmid = {37630469}, issn = {2076-2607}, support = {КП-06-Н36/7 from 13 December 2019//National Fund for Scientific Research, Republic of Bulgaria/ ; }, abstract = {Escherichia coli (E. coli) is a ubiquitous microorganism with pathogenic and saprophytic clones. The objective of this study was to evaluate the presence, virulence, antibiotic resistance and biofilm formation of E. coli in three industrial farms in Bulgaria, as well as their adjacent sites related to the utilization of manure (feces, wastewater in a separator, lagoons, means of transport, and soils). The isolation of single bacterial cultures was performed via standard procedures with modifications, and E. coli isolates were identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR). The disk diffusion method was used to assess antimicrobial resistance, and PCR was used to detect genes for antibiotic resistance (GAR) (qnr, aac(3), ampC, blaSHV/blaTEM and erm) and virulence genes (stx, stx2all, LT, STa, F4 and eae). The protocol of Stepanović was utilized to measure the biofilm formation of the isolates. A total of 84 isolates from different samples (n = 53) were identified as E. coli. Almost all demonstrated antimicrobial resistance, and most of them demonstrated resistance to multiple antibiotics from different classes. No virulence genes coding the Shiga toxin or enterotoxins or those associated with enteropathogenicity were detected. No GAR from those tested for quinolones, aminoglycosides and macrolides were found. However, all isolates that were resistant to a penicillin-class antibiotic (56) had β-lactamase-producing plasmid genes. All of them had ampC, and 34 of them had blaTEM. A total of 14 isolates formed strongly adherent biofilms. These results in a country where the use of antibiotics for growth promotion and prophylaxis in farms is highly restricted corroborate that the global implemented policy on antibiotics in human medicine and in animal husbandry needs revision.}, } @article {pmid37629016, year = {2023}, author = {Choi, E and Murray, B and Choi, S}, title = {Biofilm and Cancer: Interactions and Future Directions for Cancer Therapy.}, journal = {International journal of molecular sciences}, volume = {24}, number = {16}, pages = {}, doi = {10.3390/ijms241612836}, pmid = {37629016}, issn = {1422-0067}, support = {2016R1D1A1B01009752//by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education/ ; }, abstract = {There is a growing body of evidence supporting the significant role of bacterial biofilms in the pathogenesis of various human diseases, including cancer. Biofilms are polymicrobial communities enclosed within an extracellular matrix composed of polysaccharides, proteins, extracellular DNA, and lipids. This complex matrix provides protection against antibiotics and host immune responses, enabling the microorganisms to establish persistent infections. Moreover, biofilms induce anti-inflammatory responses and metabolic changes in the host, further facilitating their survival. Many of these changes are comparable to those observed in cancer cells. This review will cover recent research on the role of bacterial biofilms in carcinogenesis, especially in colorectal (CRC) and gastric cancers, emphasizing the shared physical and chemical characteristics of biofilms and cancer. This review will also discuss the interactions between bacteria and the tumor microenvironment, which can facilitate oncogene expression and cancer progression. This information will provide insight into developing new therapies to identify and treat biofilm-associated cancers, such as utilizing bacteria as delivery vectors, using bacteria to upregulate immune function, or more selectively targeting biofilms and cancer for their shared traits.}, } @article {pmid37628010, year = {2023}, author = {Ji, QY and Wang, W and Yan, H and Qu, H and Liu, Y and Qian, Y and Gu, R}, title = {The Effect of Different Organic Acids and Their Combination on the Cell Barrier and Biofilm of Escherichia coli.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {16}, pages = {}, doi = {10.3390/foods12163011}, pmid = {37628010}, issn = {2304-8158}, support = {31972094//National Natural Science Foundation of China/ ; 2022YFD2101503//National Key R&D Program of China/ ; YZ2020265//Key Laboratory of Probiotics and Dairy Deep Processing/ ; }, abstract = {Organic acids are natural antimicrobial compounds commonly used in the food industry. In this study, acetic, lactic, butyric, citric, and malic acid at minimum inhibitory concentrations and their combinations at optimal inhibition concentrations were used to treat E. coli, and the effects on the cell barrier and biofilm of E. coli were evaluated. Acetic acid showed the highest membrane-damaging effect, while citric acid and malic acid could specifically damage the cell wall of E. coli, leading to alkaline phosphatase leakage. The RT-qPCR results showed that organic acids upregulated the membrane-protein-related genes of E. coli, and the combination of organic acids had a wider range of effects than single organic acid treatment. Moreover, organic acids inhibited the formation of E. coli biofilm and cellular activity within the biofilm. This study showed that the combination of organic acids plays a synergistic inhibitory role mainly through multiple destructive effects on the cell barrier and exhibited synergistic anti-biofilm effects. The three-three combination of acetic, lactic acid, and a third organic acid (butyric, citric, or malic) can play a better synergistic antibacterial effect than the two-pair combination of acetic and lactic acid. These findings have implications for the usage, development, and optimization of organic acid combinations.}, } @article {pmid37627697, year = {2023}, author = {Petrillo, F and Sinoca, M and Fea, AM and Galdiero, M and Maione, A and Galdiero, E and Guida, M and Reibaldi, M}, title = {Candida Biofilm Eye Infection: Main Aspects and Advance in Novel Agents as Potential Source of Treatment.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antibiotics12081277}, pmid = {37627697}, issn = {2079-6382}, abstract = {Fungi represent a very important cause of microbial eye infections, especially in tropical and developing countries, as they could cause sight-threating disease, such as keratitis and ocular candidiasis, resulting in irreversible vision loss. Candida species are among the most frequent microorganisms associated with fungal infection. Although Candida albicans is still the most frequently detected organism among Candida subspecies, an important increase in non-albicans species has been reported. Mycotic infections often represent an important diagnostic-clinical problem due to the difficulties in performing the diagnosis and a therapeutic problem due to the limited availability of commercial drugs and the difficult penetration of antifungals into ocular tissues. The ability to form biofilms is another feature that makes Candida a dangerous pathogen. In this review, a summary of the state-of-the-art panorama about candida ocular pathology, diagnosis, and treatment has been conducted. Moreover, we also focused on new prospective natural compounds, including nanoparticles, micelles, and nanocarriers, as promising drug delivery systems to better cure ocular fungal and biofilm-related infections. The effect of the drug combination has also been examined from the perspective of increasing efficacy and improving the course of infections caused by Candida which are difficult to fight.}, } @article {pmid37627682, year = {2023}, author = {Parga, A and Balboa, S and Otero-Casal, P and Otero, A}, title = {New Preventive Strategy against Oral Biofilm Formation in Caries-Active Children: An In Vitro Study.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antibiotics12081263}, pmid = {37627682}, issn = {2079-6382}, support = {DTS-21/00015//Instituto de Salud Carlos III/ ; ED481A-2019/194//Xunta de Galicia/ ; }, abstract = {Quorum quenching (QQ) is the inhibition of bacterial communication, i.e., quorum sensing (QS). QS is a key mechanism in regulating biofilm formation and phenotype in complex bacterial communities, such as those found within cariogenic biofilms. Whereas QQ approaches were shown to effectively reduce biomass, knowledge of their impact on the taxonomic composition of oral polymicrobial biofilms remains scarce. Here, we investigate the effect of the QQ lactonase Aii20J on biomass production and taxonomical composition of biofilms. We collected supragingival plaque samples from 10 caries-free and 10 caries-active children and cultured them to generate in vitro biofilms. We describe significant biomass reductions upon Aii20J exposure, as assessed by crystal violet assays. Taxonomical profiling using 16S rRNA gene amplicon sequencing revealed no significant changes in bacterial composition at the genus level. Interestingly, at the species level Aii20J-treatment increased the abundance of Streptococcus cristatus and Streptococcus salivarius. Both S. cristatus and S. salivarius express pH-buffering enzymes (arginine deiminase and urease, respectively) that catalyze ammonia production, thereby potentially raising local pH and counteracting the biofilm's cariogenic potential. Within the limitations of the study, our findings provide evidence of the biofilm-modulating ability of QQ and offer novel insights into alternative strategies to restore homeostasis within dysbiotic ecosystems.}, } @article {pmid37627679, year = {2023}, author = {Elshenawi, Y and Hu, S and Hathroubi, S}, title = {Biofilm of Helicobacter pylori: Life Cycle, Features, and Treatment Options.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antibiotics12081260}, pmid = {37627679}, issn = {2079-6382}, abstract = {Helicobacter pylori is a gastric pathogen that infects nearly half of the global population and is recognized as a group 1 carcinogen by the Word Health Organization. The global rise in antibiotic resistance has increased clinical challenges in treating H. pylori infections. Biofilm growth has been proposed to contribute to H. pylori's chronic colonization of the host stomach, treatment failures, and the eventual development of gastric diseases. Several components of H. pylori have been identified to promote biofilm growth, and several of these may also facilitate antibiotic tolerance, including the extracellular matrix, outer membrane proteins, shifted morphology, modulated metabolism, efflux pumps, and virulence factors. Recent developments in therapeutic approaches targeting H. pylori biofilm have shown that synthetic compounds, such as small molecule drugs and plant-derived compounds, are effective at eradicating H. pylori biofilms. These combined topics highlight the necessity for biofilm-based research in H. pylori, to improve current H. pylori-targeted therapeutic approaches and alleviate relative public health burden. In this review we discuss recent discoveries that have decoded the life cycle of H. pylori biofilms and current biofilm-targeted treatment strategies.}, } @article {pmid37627668, year = {2023}, author = {Silva, A and Silva, V and López, M and Rojo-Bezares, B and Carvalho, JA and Castro, AP and Sáenz, Y and Igrejas, G and Poeta, P}, title = {Antimicrobial Resistance, Genetic Lineages, and Biofilm Formation in Pseudomonas aeruginosa Isolated from Human Infections: An Emerging One Health Concern.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antibiotics12081248}, pmid = {37627668}, issn = {2079-6382}, abstract = {Pseudomonas aeruginosa (PA) is a leading nosocomial pathogen and has great versatility due to a complex interplay between antimicrobial resistance and virulence factors. PA has also turned into one the most relevant model organisms for the study of biofilm-associated infections. The objective of the study focused on analyzing the antimicrobial susceptibility, resistance genes, virulence factors, and biofilm formation ability of thirty-two isolates of PA. PA isolates were characterized by the following analyses: susceptibility to 12 antimicrobial agents, the presence of resistance genes and virulence factors in PCR assays, and the quantification of biofilm production as evaluated by two distinct assays. Selected PA isolates were analyzed through multilocus sequence typing (MLST). Thirty PA isolates have a multi-resistant phenotype, and most of the isolates showed high levels of resistance to the tested antibiotics. Carbapenems showed the highest prevalence of resistance. Various virulence factors were detected and, for the quantification of biofilm production, the effectiveness of different methods was assessed. The microtiter plate method showed the highest accuracy and reproducibility for detecting biofilm-producing bacteria. MLST revealed four distinct sequence types (STs) in clinical PA, with three of them considered high-risk clones of PA, namely ST175, ST235, and ST244. These clones are associated with multidrug resistance and are prevalent in hospitals worldwide. Overall, the study highlights the high prevalence of antibiotic resistance, the presence of carbapenemase genes, the diversity of virulence factors, and the importance of biofilm formation in PA clinical isolates. Understanding these factors is crucial for effective infection control measures and the development of targeted treatment strategies.}, } @article {pmid37627665, year = {2023}, author = {Li, H and Niu, C and Luo, J and Huang, Z and Zhou, W}, title = {Anticariogenic Activity of Celastrol and Its Enhancement of Streptococcal Antagonism in Multispecies Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antibiotics12081245}, pmid = {37627665}, issn = {2079-6382}, support = {82100990//National Natural Science Foundation of China/ ; 82071104//National Natural Science Foundation of China/ ; 81570964//National Natural Science Foundation of China/ ; SHDC12022120//Shanghai Hospital Development Center/ ; NCRCO2021-omics-07//National Clinical Research Center for Oral Diseases/ ; 19MC1910600//Shanghai Clinical Research Center for Oral Diseases/ ; JYJC202223/KQYJXK2020//Shanghai Ninth People's Hospital affiliated with Shanghai Jiao Tong University, School of Medicine/ ; }, abstract = {Dental caries is a chronic disease resulting from dysbiosis in the oral microbiome. Antagonism of commensal Streptococcus sanguinis and Streptococcus gordonii against cariogenic Streptococcus mutans is pivotal to keep the microecological balance. However, concerns are growing on antimicrobial agents in anticaries therapy, for broad spectrum antimicrobials may have a profound impact on the oral microbial community, especially on commensals. Here, we report celastrol, extracted from Traditional Chinese Medicine's Tripterygium wilfordii (TW) plant, as a promising anticaries candidate. Our results revealed that celastrol showed antibacterial and antibiofilm activity against cariogenic bacteria S. mutans while exhibiting low cytotoxicity. By using a multispecies biofilm formed by S. mutans UA159, S. sanguinis SK36, and S. gordonii DL1, we observed that even at relatively low concentrations, celastrol reduced S. mutans proportion and thereby inhibited lactic acid production as well as water-insoluble glucan formation. We found that celastrol thwarted S. mutans outgrowth through the activation of pyruvate oxidase (SpxB) and H2O2-dependent antagonism between commensal oral streptococci and S. mutans. Our data reveal new anticaries properties of celastrol that enhance oral streptococcal antagonism, which thwarts S. mutans outgrowth, indicating its potential to maintain oral microbial balance for prospective anticaries therapy.}, } @article {pmid37627574, year = {2023}, author = {Tian, D and Qiao, Y and Peng, Q and Zhang, Y and Gong, Y and Shi, L and Xiong, X and He, M and Xu, X and Shi, B}, title = {A Poly-D-Mannose Synthesized by a One-Pot Method Exhibits Anti-Biofilm, Antioxidant, and Anti-Inflammatory Properties In Vitro.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/antiox12081579}, pmid = {37627574}, issn = {2076-3921}, support = {6232039//Beijing Natural Science Foundation/ ; 1610382023018//Basal Research Fund of Feed Research Institute, Chinese Academy of Agricultural Sciences/ ; 32072773//National Natural Science Foundation of China/ ; }, abstract = {In this study, D-mannose was used to synthesize poly-D-mannose using a one-pot method. The molecular weight, degree of branching, monosaccharide composition, total sugar content, and infrared spectrum were determined. In addition, we evaluated the safety and bioactivity of poly-D-mannose including anti-pathogen biofilm, antioxidant, and anti-inflammatory activity. The results showed that poly-D-mannose was a mixture of four components with different molecular weights. The molecular weight of the first three components was larger than 410,000 Da, and that of the fourth was 3884 Da. The branching degree of poly-D-mannose was 0.53. The total sugar content was 97.70%, and the monosaccharide was composed only of mannose. The infrared spectra showed that poly-D-mannose possessed characteristic groups of polysaccharides. Poly-D-mannose showed no cytotoxicity or hemolytic activity at the concentration range from 0.125 mg/mL to 8 mg/mL. In addition, poly-D-mannose had the best inhibition effect on Salmonella typhimurium at the concentration of 2 mg/mL (68.0% ± 3.9%). The inhibition effect on Escherichia coli O157:H7 was not obvious, and the biofilm was reduced by 37.6% ± 2.9% at 2 mg/mL. For Staphylococcus aureus and Bacillus cereus, poly-D-mannose had no effect on biofilms at low concentration; however, 2 mg/mL of poly-D-mannose showed inhibition rates of 33.7% ± 6.4% and 47.5% ± 4%, respectively. Poly-D-mannose showed different scavenging ability on free radicals. It showed the best scavenging effect on DPPH, with the highest scavenging rate of 74.0% ± 2.8%, followed by hydroxyl radicals, with the scavenging rate of 36.5% ± 1.6%; the scavenging rates of superoxide anion radicals and ABTS radicals were the lowest, at only 10.1% ± 2.1% and 16.3% ± 0.9%, respectively. In lipopolysaccharide (LPS)-stimulated macrophages, poly-D-mannose decreased the secretion of nitric oxide (NO) and reactive oxygen species (ROS), and down-regulated the expression of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Therefore, it can be concluded that poly-D-mannose prepared in this research is safe and has certain biological activity. Meanwhile, it provides a new idea for the development of novel prebiotics for food and feed industries or active ingredients used for pharmaceutical production in the future.}, } @article {pmid37626952, year = {2023}, author = {Vinoth, M and Sivasankari, S and Ahamed, AKK and Alsamhary, KI and Al-Enazi, NM and Abdel-Raouf, N and Alharbi, RM and Govindarajan, RK and Ravi, G and Alarjani, KM and Sholkamy, EN}, title = {Bio-Characterization and Liquid Chromatography-Mass Spectrometry Analysis of Exopolysaccharides in Biofilm-Producing Cyanobacteria Isolated from Soil Crust: Exploring the Potential of Microalgal Biomolecules.}, journal = {Biology}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/biology12081065}, pmid = {37626952}, issn = {2079-7737}, abstract = {Exopolysaccharide-producing cyanobacterial strains in biological soil crusts are described, in addition to their chemical properties and antioxidant and flocculation activities. The EPSs from Pudukkottai blackish biological soil crusts (PBBSCs) showed significant amounts of total soluble proteins (0.1687 mg/mL) and carbohydrates (0.8056 mg/mL) compared with the Ariyalur blackish biological soil crusts (ABBSCs). LC-MS analysis of the cyanobacterial polysaccharides revealed the presence of natural sugars such as ribose and glucose/mannose, and uronic acids. The FTIR spectrum showed specific peak for OH and -NH stretching, C-H stretching, and carboxylic acids as the dominant groups in EPS. The in vitro DPPH assay of EPSs from PBBSCs showed 74.3% scavenging activity. Furthermore, the reducing power was determined to be 0.59 ata 500 mg/mL concentration, respectively. The extracted EPSs from the biological soil crust flocculated Kaolin clay suspension maximum at 500 mg/mL. Consequently, the cyanobacterial strain and exopolysaccharide characterization from the sacred forest's biological soil crust were analyzed for their bioactive potential, bio-crust diversity, and distribution.}, } @article {pmid37625903, year = {2023}, author = {Tsikopoulos, A and Tsikopoulos, K and Meroni, G and Drago, L and Triaridis, S and Papaioannidou, P}, title = {Strategies for Inhibition of Biofilm Formation on Silicone Rubber Voice Prostheses: A Systematic Review.}, journal = {Journal of voice : official journal of the Voice Foundation}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jvoice.2023.07.015}, pmid = {37625903}, issn = {1873-4588}, abstract = {BACKGROUND: Lifetime elongation of the silicone voice rubber prostheses by inhibition of biofilm formation is a primary objective in voice restoration of laryngectomized patients. This systematic review sought to explore the existing strategies in this direction.

MATERIALS: We conducted a systematic search of both in vitro and in vivo literature published in PubMed, Scopus, and Cochrane Central Register of Controlled Trials, until December 31, 2022, for published and unpublished trials assessing the strategies for inhibiting biofilm formation on silicone rubber voice prostheses, and appraised quality assessment with the modified Consolidated Standards of Reporting Trials tool. We analyzed the infection prevention capacity of the included antibacterial and antifungal agents.

RESULTS: The qualitative synthesis showed that both surface modification methods and prophylactic treatment of silicone rubber voice prostheses present adequate antibiofilm activity. Of note, the majority of the suggested prosthetic surfaces were not chronically exposed to both human fluids and biofilm-forming microorganisms.

CONCLUSION: Various experimental methods provide promising antibiofilm activity and, thus, possible lifespan elongation of silicone rubber voice prostheses.}, } @article {pmid37625678, year = {2023}, author = {Zou, Y and Zhang, H and Zhang, Y and Wu, Y and Cheng, J and Jia, D and Liu, C and Chen, H and Zhang, Y and Yu, Q}, title = {A near-infrared light-triggered nano-domino system for efficient biofilm eradication: Activation of dispersing and killing functions by generating nitric oxide and peroxynitrite via cascade reactions.}, journal = {Acta biomaterialia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.actbio.2023.08.038}, pmid = {37625678}, issn = {1878-7568}, abstract = {One of the serious threats to global public health is the bacterial biofilm, which results in numerous persistent and recurrent infections. Herein, we proposed a near-infrared (NIR) light-triggered "nano-domino" system with "dispersing and killing" functionality for biofilm eradication. The nanoplatform was fabricated by the self-assembly of chitosan conjugated with L-arginine (L-Arg, a natural NO donor) and indocyanine green (ICG, a phototherapy agent). Using an NIR irradiation "trigger", a series of reactive oxygen species (ROS) including singlet oxygen ([1]O2), hydrogen peroxide (H2O2), and superoxide anions (·O2[-]), as well as heat were generated from ICG aggregates. Subsequently, [1]O2 and H2O2 catalyzed L-Arg to produce NO, which dispersed the biofilm and reacted with ·O2[-] to form peroxynitrite to kill bacteria with ROS collaboratively. Meanwhile, the generated heat increased the permeability of bacterial membranes, aggravating the damage to biofilm bacteria. The experiments on biofilm eradication demonstrated that this "nano-domino" system was capable to eradicate over 99.99% of biofilms formed by Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa under 5-min NIR irradiation. Notably, these integrated benefits allowed the system to promote the healing of MRSA biofilm-infected wounds in vivo with negligible toxicity. Overall, this reported NIR-triggered "nano-domino" system holds great promise for addressing the difficulties associated with bacterial biofilm eradication. STATEMENT OF SIGNIFICANCE: Novel agents for biofilm eradication are urgently needed due to the alarming rise in antimicrobial resistance to conventional antibiotics and the critical shortage of new drugs. In this study, we create a nano-domino system that uses near-infrared (NIR) light as a trigger to eradicate mature biofilms. In response to a short-term NIR irradiation, the proposed nanoplatform could generate nitric oxide and peroxynitrite to disperse the biofilm and kill the bacteria inside, respectively, leading to efficient eradication of Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa biofilms with minimal cytotoxicity. The findings, therefore, indicate that this nanoplatform with enhanced antibiofilm performance might provide a reliable and promising solution to biofilm-related problems.}, } @article {pmid37625295, year = {2023}, author = {Oliveira, IM and Gomes, IB and Moniz, T and Simões, LC and Rangel, M and Simões, M}, title = {Realism-based assessment of the efficacy of potassium peroxymonosulphate on Stenotrophomonas maltophilia biofilm control.}, journal = {Journal of hazardous materials}, volume = {460}, number = {}, pages = {132348}, doi = {10.1016/j.jhazmat.2023.132348}, pmid = {37625295}, issn = {1873-3336}, abstract = {The potential of pentapotassium bis(peroxymonosulphate) bis(sulphate) (OXONE) to control biofilms in drinking water distribution systems (DWDS) was evaluated and compared to chlorine disinfection. Mature biofilms of drinking water (DW)-isolated Stenotrophomonas maltophilia were formed using a simulated DWDS with a rotating cylinder reactor (RCR). After 30 min of exposure, OXONE at 10 × minimum bactericidal concentration (MBC) caused a significant 4 log reduction of biofilm culturability in comparison to the unexposed biofilms and a decrease in the number of non-damaged cells below the detection limit (4.8 log cells/cm[2]). The effects of free chlorine were restricted to approximately 1 log reduction in both biofilm culturability and non-damaged cells. OXONE in synthetic tap water (STW) at 25 ºC was more stable over 40 days than free chlorine in the same conditions. OXONE solution exhibited a disinfectant decrease of about 10% of the initial concentration during the first 9 days, and after this time the values remained stable. Whereas possible reaction of chlorine with inorganic and organic substances in STW contributed to free chlorine depletion of approximately 48% of the initial concentration. Electron paramagnetic resonance (EPR) spectroscopy studies confirmed the presence of singlet oxygen and other free radicals during S. maltophilia disinfection with OXONE. Overall, OXONE constitutes a relevant alternative to conventional DW disinfection for effective biofilm control in DWDS.}, } @article {pmid37624024, year = {2023}, author = {Oliveira, F and Gaio, V and Brás, S and Oliveira, S and França, A}, title = {Host Soluble Factors Cause Changes in Staphylococcus epidermidis Antibiotic Susceptibility and Biofilm Formation Ability.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/pathogens12081064}, pmid = {37624024}, issn = {2076-0817}, support = {UIDB/04469/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {Staphylococcus epidermidis is a major nosocomial pathogen with a remarkable ability to adhere to the surfaces of indwelling medical devices and form biofilms. Unlike other nosocomial pathogens, the interaction of S. epidermidis with host factors has not been the focus of substantial research. This study aimed to assess the alterations in the antibiotic susceptibility and biofilm formation ability of S. epidermidis in the presence of host serum factors. S. epidermidis strain RP62A was cultured in a laboratory culture medium with or without human serum/plasma, and changes in antibiotic susceptibility, biofilm formation, and gene expression were evaluated. The data obtained revealed that exposure to host serum factors increased the susceptibility of S. epidermidis to glycopeptide antibiotics and was also detrimental to biofilm formation. Gene expression analysis revealed downregulation of both dltA and fmtC genes shortly after human serum/plasma exposure. The importance of transferrin-mediated iron sequestration as a host anti-biofilm strategy against S. epidermidis was also emphasized. We have demonstrated that serum factors play a pivotal role as part of the host's anti-infective strategy against S. epidermidis infections, highlighting the importance of incorporating such factors during in vitro studies with this pathogen.}, } @article {pmid37623935, year = {2023}, author = {Kasperski, T and Romaniszyn, D and Jachowicz-Matczak, E and Pomorska-Wesołowska, M and Wójkowska-Mach, J and Chmielarczyk, A}, title = {Extensive Drug Resistance of Strong Biofilm-Producing Acinetobacter baumannii Strains Isolated from Infections and Colonization Hospitalized Patients in Southern Poland.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, doi = {10.3390/pathogens12080975}, pmid = {37623935}, issn = {2076-0817}, support = {2020/39/O/NZ7/00145//National Science Center/ ; DBS/000698//Jagiellonian University/ ; }, abstract = {Acinetobacter baumannii (AB) is a bacterium that causes infections, particularly in immunocompromised patients. Treatment is challenging due to biofilm formation by AB strains, which hinders antibiotic effectiveness and promotes drug resistance. The aim of our study was to analyze the biofilm-producing capacity of AB isolates from various forms of infections in relation to biofilm-related genes and their drug resistance. We tested one hundred isolates for biofilm formation using the crystal violet microplate method. Drug resistance analyses were performed based on EUCAST and CLSI guidelines, and biofilm genes were detected using PCR. All tested strains were found to form biofilms, with 50% being ICU strains and 72% classified as strong biofilm producers. Among these, 87% were extensively drug-resistant (XDR) and 2% were extra-extensively drug-resistant (E-XDR). The most common gene set was bap, bfmS, csuE, and ompA, found in 57% of all isolates. Our research shows that, regardless of the form of infection, biofilm-forming strains can be expected among AB isolates. The emergence of E-XDR and XDR strains among non-ICU infections highlights the necessity for the rational use of antibiotics to stop or limit the further acquisition of drug resistance by A. baumannii.}, } @article {pmid37622278, year = {2023}, author = {Guedes, GM and Araújo, ES and Ribeiro, KV and Pereira, VC and Soares, AC and Freitas, AS and Amando, BR and Cordeiro, RA and Rocha, MF and Sidrim, JJ and Castelo-Branco, DS}, title = {Effect of fluoxetine on planktonic and biofilm growth and the antimicrobial susceptibility of Burkholderia pseudomallei.}, journal = {Future microbiology}, volume = {}, number = {}, pages = {}, doi = {10.2217/fmb-2022-0272}, pmid = {37622278}, issn = {1746-0921}, support = {403795/2021-4, 405312/2021-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {Aim: This study evaluated the effect of fluoxetine (FLU) on planktonic and biofilm growth and the antimicrobial susceptibility of Burkholderia pseudomallei. Materials & methods: The minimum inhibitory concentrations (MICs) for FLU were determined by broth microdilution. Its effect on growing and mature biofilms and its interaction with antibacterial drugs were evaluated by assessing biofilm metabolic activity, biomass and structure through confocal microscopy. Results: The FLU MIC range was 19.53-312.5 μg/ml. FLU eradicated growing and mature biofilms of B. pseudomallei at 19.53-312.5 μg/ml and 1250-2500 μg/ml, respectively, with no structural alterations and enhanced the antibiofilm activity of antimicrobial drugs. Conclusion: These results bring perspectives for the use of FLU in the treatment of melioidosis, requiring further studies to evaluate its applicability.}, } @article {pmid37621399, year = {2023}, author = {Ma, X and Wang, L and Yang, F and Li, J and Guo, L and Guo, Y and He, S}, title = {Drug sensitivity and genome-wide analysis of two strains of Mycoplasma gallisepticum with different biofilm intensity.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1196747}, pmid = {37621399}, issn = {1664-302X}, abstract = {Mycoplasma gallisepticum (MG) is one of the major causative agents of chronic respiratory diseases in poultry. The biofilms of MG are highly correlated to its chronic infection. However data on genes involved in biofilm formation ability are still scarse. MG strains with distinct biofilm intensity were screened by crystal violet staining morphotyped and characterized for the drug sensitivity. Two MG strains NX-01 and NX-02 showed contrasted ability to biofilm formation. The biofilm formation ability of NX-01 strain was significantly higher than that of NX-02 strain (p < 0.01). The drug sensitivity test showed that the stronger the ability of MG stain to form biofilms, the weaker its sensitivity to 17 antibiotic drugs. Moreover, putative key genes related to biofilm formation were screened by genome-wide analysis. A total of 13 genes and proteins related to biofilm formation, including ManB, oppA, oppD, PDH, eno, RelA, msbA, deoA, gapA, rpoS, Adhesin P1 precursor, S-adenosine methionine synthetase, and methionyl tRNA synthetase were identified. There were five major discrepancies between the two isolated MG strains and the five NCBI-published MG strains. These findings provide potential targets for inhibiting the formation of biofilm of MG, and lay a foundation for treating chronic infection.}, } @article {pmid37619456, year = {2023}, author = {Zhang, H and Yi, X and Chen, M and Shi, H and Tan, L and Lu, H and Sun, Y and Yang, F}, title = {Synergistic effect of chlorhexidine and azoles on candida biofilm on titanium surface.}, journal = {Journal de mycologie medicale}, volume = {33}, number = {4}, pages = {101417}, doi = {10.1016/j.mycmed.2023.101417}, pmid = {37619456}, issn = {1773-0449}, abstract = {BACKGROUND: Candida infections of orthopedic implants are one of the most detrimental orthopedic implant-related complications with unsuccessful treatment and a poor prognosis. Most orthopedic Candida infections form biofilms and have resistance to the commonly used antifungal agents. This study aimed to develop a novel combination of normally prescribed drugs against Candida biofilm on orthopedic implants.

METHODS: We cultured 26 clinical isolates of Candida strains to form biofilm without titanium sheets or on titanium sheets, which are the most commonly used materials for permanent or orthopedic implants. The checkerboard method was used to evaluate the synergistic effects of chlorhexidine (CHL) and azoles on these Candida biofilms. For the evaluation of synergistic effects, we constructed the cell viability assay by fluorescence staining and CFU reduction hot map of Candida.

RESULTS: Twenty-six clinical isolates of Candida strains formed biofilm in 96-well plates without titanium sheets, and we selected 9 of them to form biofilm on titanium sheets in 24-well plates. In Candida biofilm formed in 96-wells, the synergistic rates of CHL with fluconazole, itraconazole, and voriconazole were 61% (16/26), 65% (17/26), and 23% (6/26), respectively. When compared to the blank control group, CHL monotherapy significantly inhibited biofilm formation on titanium sheets (P < 0.05). We demonstrated 100% synergistic rates of the CHL and fluconazole combination against Candida biofilm formation on titanium sheets, and the minimum inhibitory concentration of CHL and FLU decreased four- to eight-fold.

CONCLUSIONS: We concluded that CHL combined with azoles inhibited the Candida biofilm formation 96-wells or on titanium sheets and has the potential to control the infections of orthopedic implants.}, } @article {pmid37614873, year = {2023}, author = {Flowers, S and Holder, KH and Gardner, SM}, title = {Here Is the Biology, Now What is the Mechanism? Investigating Biology Undergraduates' Mechanistic Reasoning within the Context of Biofilm Development.}, journal = {Journal of microbiology & biology education}, volume = {24}, number = {2}, pages = {}, pmid = {37614873}, issn = {1935-7877}, abstract = {Understanding molecular processes and coordinating the various activities across levels of organization in biological systems is a complicated task, yet many curricular guidelines indicate that undergraduate students should master it. Employing mechanistic reasoning can facilitate describing and investigating biological phenomena. Biofilms are an important system in microbiology and biology education. However, few empirical studies have been conducted on student learning of biofilms or how students utilize mechanistic reasoning related to systems thinking to explain biofilm formation. Using mechanistic reasoning and the theory of knowledge integration as conceptual and analytical frameworks, we examined the features of 9 undergraduate biology students' mechanistic models of a specific transition point in biofilm development. From these data, we constructed a model of knowledge integration in the context of biofilms, which categorizes students' knowledge based on features of their descriptions (e.g., entities, correct connections, and the nature of connections). We found that 4 of 9 students produced a fragmented model, 4 of 9 students produced a transitional model, and 1 student produced a connected model. Overall, students often did not discuss cell-cell communication mechanics in their mechanistic models and rarely included the role of gene regulation. Most connections were considered nonnormative and lacked important entities, leading to an abundance of unspecified causal connections. We recommend increasing instructional support of mechanistic reasoning within systems (e.g., identifying entities across levels of organization and their relevant activities) and creating opportunities for students to grapple with their understanding of various biological concepts and to explore how processes interact and connect in a complex system.}, } @article {pmid37613496, year = {2023}, author = {Wang, Y and Osire, T and Sokolova, OS}, title = {In vitro Biofilm Formation by Bacillus subtilis and AR9 Phage Infection: SEM Study.}, journal = {Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada}, volume = {29}, number = {Supplement_1}, pages = {1133-1134}, doi = {10.1093/micmic/ozad067.579}, pmid = {37613496}, issn = {1435-8115}, } @article {pmid37612795, year = {2023}, author = {Asraoui, F and El Mansouri, F and Cacciola, F and Brigui, J and Louajri, A and Simonetti, G}, title = {Biofilm Inhibition of Inula viscosa (L.) Aiton and Globularia alypum L. Extracts Against Candida Infectious Pathogens and In Vivo Action on Galleria mellonella Model.}, journal = {Advanced biology}, volume = {}, number = {}, pages = {e2300081}, doi = {10.1002/adbi.202300081}, pmid = {37612795}, issn = {2701-0198}, abstract = {The increasing importance of fungal infections has fueled the search for new beneficial alternatives substance from plant extracts. The current study investigates the antifungal and antibiofilm activity of Inula viscosa (L.) Aiton and Globularia alypum (L.) leaves extracts against Candida both in vitro and in vivo. The inhibition of planktonic and sessile Candida albicans and Candida glabrata growth using both leaf extracts are evaluated. Moreover; an in vivo infection model using Galleria mellonella larvae; infected and treated with the extracts are performed. All extracts show fungicidal activity; with a minimum fungicidal concentration (MFC) ranging from 128 to 512 µg mL[-1] against the two selected strains of Candida. In particular, the best results are obtained with methanolic extract of I. viscosa and G. alypum with an MFC value of 128 µg mL[-1] . The extracts are capable to prevent 90% of biofilm development at minor concentrations ranging from 100.71 ± 2.49 µg mL[-1] to 380.4 ± 0.92 µg mL[-1] . In vivo, tests on Galleria mellonella larvae show that the extracts increase the survival of the larvae infected with Candida. The attained results reveal that I. viscosa and G. alypum extracts may be considered as new antifungal agents and biofilm inhibiting agents for the pharmaceutical and agro-food field.}, } @article {pmid37612659, year = {2023}, author = {Rahimi, S and Bakht, M and Javadi, A and Foroughi, F and Marashi, SMA and Nikkhahi, F}, title = {Characterization of novel bacteriophage PSKP16 and its therapeutic potential against β-lactamase and biofilm producer strain of K2-Hypervirulent Klebsiella pneumoniae pneumonia infection in mice model.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {233}, pmid = {37612659}, issn = {1471-2180}, abstract = {BACKGROUND: Severe infections caused by β- lactamase producers, hypervirulent Klebsiella pneumoniae (BhvKp) with K2 serotype, highlight emergency need for new therapeutic strategies against this pathogen. We aimed to assess the efficacy of a novel phage, PSKP16, in the treating of pneumonia induced by BhvKp in mice models.

METHOD: Genome sequences of PSKP16 were analyzed, and associated information can be found in NCBI. We applied treatment in two ways: by using mice for immediate and delayed treatments. Moreover, acute pneumonia obtained by BhvKp with intranasal method, was characterized in terms of histopathology of pulmonary lesions, biomarkers of inflammation level, leukocytes cells infiltration extent in mice, and was assessed treatment of them with PSKP16 multiplicity of infection (MOI: 10), either individually or in combination with gentamicin. Assessment of the ability of PSKP16 to inhibit BhvKp biofilm was studied.

RESULTS: PSKP16 was associated with the Drexlerviridae family, and had a genome size of 46,712 bp, and 67 predicted ORFs. Herein, prompt phage administration's efficacy to decrease bacterial load and improve the survival rate in pneumonia models was faster than the synergism model with delay, but both almost displayed similar endpoints. The distribution of BhvKp strains in the lung was consistent with the histopathological findings, simultaneous inflammation, and level of serum tumor necrosis factor-α (TNF α). The phage treatment presented a lack of severe lesions and alveolar edema, reduction of inflammatory cell infiltration, which not only was it not associated with an over-inflammation but also provided a faster correction of blood cell count abnormalities compared to gentamicin. Phage with a high concentration in in vitro model effectively eliminated biofilms.

CONCLUSION: It is essential to raise clinical awareness and management of BhvKp infections, signaled as the next superbug in waiting. The results of our study underscore the importance of PSKP16 as a phage with promising therapeutic potential in treating BhvKp-induced pneumonia.}, } @article {pmid37612330, year = {2023}, author = {Stewart, PS and Owkes, M}, title = {Simulation of catalase-dependent tolerance of microbial biofilm to hydrogen peroxide with a biofilm computer model.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {60}, pmid = {37612330}, issn = {2055-5008}, abstract = {Hydrogen peroxide (HP) is a common disinfectant and antiseptic. When applied to a biofilm, it may be expected that the top layer of the biofilm would be killed by HP, the HP would penetrate further, and eventually eradicate the entire biofilm. However, using the Biofilm.jl computer model, we demonstrate a mechanism by which the biofilm can persist, and even become thicker, in the indefinite treatment with an HP solution at concentrations that are lethal to planktonic microorganisms. This surprising result is found to be dependent on the neutralization of HP by dead biomass, which provides protection for living biomass deeper within the biofilm. Practically, to control a biofilm, this result leads to the concept of treating with an HP dose exceeding a critical threshold concentration rather than a sustained, lower-concentration treatment.}, } @article {pmid37612139, year = {2023}, author = {Nuttall, RA and Moisander, PH}, title = {Vibrio cyclitrophicus population-specific biofilm formation and epibiotic growth on marine copepods.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16483}, pmid = {37612139}, issn = {1462-2920}, support = {//Massachusetts Division of Marine Fisheries/ ; N00014220-1-2170//Office of Naval Research/ ; }, abstract = {Vibrio spp. form a part of the microbiome of copepods-an abundant component of marine mesozooplankton. The biological mechanisms of the Vibrio-copepod association are largely unknown. In this study we compared biofilm formation of V. cyclitrophicus isolated from copepods (L-strains related to other particle-associated strains) and closely related strains originating from seawater (S-strains), and visualized and quantified their attachment and growth on copepods. The S- and L-strains formed similar biofilms in the presence of complete sea salts, suggesting previously unknown biofilm mechanisms in the S-strains. No biofilms formed if sodium chloride was present as the only salt but added calcium significantly enhanced biofilms in the L-strains. GFP-L-strain cells attached to live copepods at higher numbers than the S-strains, suggesting distinct mechanisms, potentially including calcium, support their colonization of copepods. The cells grew on live copepods after attachment, demonstrating that copepods sustain epibiotic V. cyclitrophicus growth in situ. The results demonstrate that in spite of their 99.1% average nucleotide identity, these V. cyclitrophicus strains have a differential capacity to colonize marine copepods. The introduced V. cyclitrophicus-A. tonsa model could be informative in future studies on Vibrio-copepod association.}, } @article {pmid37611812, year = {2023}, author = {Kumar Jaiswal, V and Dutta Gupta, A and Verma, V and Sharan Singh, R}, title = {Degradation of p-cresol in the presence of UV light driven in an integrated system containing photocatalytic and packed bed biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129706}, doi = {10.1016/j.biortech.2023.129706}, pmid = {37611812}, issn = {1873-2976}, abstract = {Integratingphotocatalysisand biodegradation has shown great potential in wastewater treatment technology. In this study, the degradation of p-cresol in water has been investigated through an integrated system comprising of photocatalytic and packed bed biofilm reactor (PBBR). In the photocatalytic reactor, the biodegradability index (BOD5/COD, BOD5/TOC) of the p-cresol solution was first shown to increase (from 0.098±0.023 to 0.59±0.089 for BOD5/COD and from 0.27±0.030 to 1.74±0.03 for BOD5/TOC). The pseudo-first-order rate constant (kap) was found to be 0.011 min[-1]. The % removal of the integrated system was found to be 98.43±1.31% at an initial concentration of 700 mg/L and residence time of 120 h, which was significantly higher than the PBBR operated alone (34.82±2.62%) under optimized conditions (pH 7.0 and T = 32±2 °C). Using an integrated approach, the efficient removal of p-cresol opens novel future perspectives for catalytic degradation using chemical oxidation.}, } @article {pmid37611758, year = {2023}, author = {Jin, C and Tang, Q and Xu, H and Sheng, Y}, title = {Effects of anode materials on nitrate reduction and microbial community in a three-dimensional electrode biofilm reactor with sulfate.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139909}, doi = {10.1016/j.chemosphere.2023.139909}, pmid = {37611758}, issn = {1879-1298}, abstract = {Graphite rod corrosion and peeling are serious problems in three-dimensional electrode biofilm reactors (3D-BERs). In this study, titanium rods, titanium suboxide-coated titanium rods and graphite rods were used as anodes to investigate the effect of anodic materials on the electrochemical and bioelectrochemical reduction of nitrate and sulfate. The results showed that the reactor with the titanium suboxide-coated titanium rod anode (3D-ER-T) exhibited a stable NO3[-]-N removal efficiency (46%-95%) with a current range of 160-320 mA in the electrochemical reduction process. In the bioelectrochemical reduction, the removal efficiencies of NO3[-]-N and SO4[2-] and nitrogen selectivity in the 3D-BER with titanium suboxide-coated titanium rod anode (3D-BER-T) were higher than those in the 3D-BER with titanium suboxide-coated graphite rod anode (3D-BER-G). The removal efficiencies of NO3[-]-N and SO4[2-] and nitrogen selectivity were 92%, 43% and 86%, respectively, in 3D-BER-T under 320 mA and HRT 12 h. Anode materials affected the microbial community. Hydrogenophaga and Dethiobacter were the dominant bacteria in 3D-BER-T, while OPB41 and Sulfurospirillum were dominant in 3D-BER-G. Nitrate and sulfate were effectively removed in 3D-BER-T by the synergistic work of electrochemical reduction, bioelectrochemical reduction and indirect electrochemical reduction. The resupply/reserve mode of the electron donor promoted the load of shock resistance of 3D-BER-T via the sulfur cycle. Titanium suboxide coating could significantly enhance the anti-corrosion ability of matrix anodes.}, } @article {pmid37611683, year = {2023}, author = {Kumar, A and Kumar, RR and Chaturvedi, V and Kayastha, AM}, title = {α-Amylase purified and characterized from fenugreek (Trigonella foenum-graecum) showed substantial anti-biofilm activity against Staphylococcus aureus MTCC740.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {126442}, doi = {10.1016/j.ijbiomac.2023.126442}, pmid = {37611683}, issn = {1879-0003}, abstract = {Starch hydrolyzing α-amylase from germinated fenugreek (Trigonella foenum-graecum) has been purified 104-fold to apparent electrophoretic homogeneity with a final specific activity of 297.5 units/mg. SDS-PAGE of the final preparation revealed a single protein band of 47.5 kDa, supported by LC/MS analysis and size-exclusion chromatography on the Superdex 200 (ÄKTA-FPLC). α-Amylase exhibited maximum activity at pH 5.5. An activation energy (Ea) of 9.12 kcal/mol was found to exist in the temperature range of 20 to 90 °C. When substrate concentrations were evaluated between 0.5 and 10 mg/mL, the Km and Vmax values for starch were observed to be 1.12 mg/mL and 384.14 μmol/min/mg, respectively. The major substrate starch exhibited high specificity for fenugreek α-amylase. In the presence of EDTA (5 mM), the activity was lost, however, it could be largely reversed with the addition of calcium. Furthermore, an effort was made to assess the ability of fenugreek seed-derived partially purified (DEAE-cellulose enzyme) and purified α-amylase to disperse inside 48 h-old biofilms of Staphylococcus aureus MTCC740. The outcomes clearly demonstrated that the purified and partially purified α-amylase both exhibited strong biofilm dispersion activity.}, } @article {pmid37610514, year = {2023}, author = {Vishwakarma, A and Verma, D}, title = {Smokeless Tobacco Harbors Bacteria Involved in Biofilm Formation as Well as Salt and Heavy Metal Tolerance Activity.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37610514}, issn = {1559-0291}, support = {F 30.442/2018/BSR//University Grants Commission - South Eastern Regional Office/ ; }, abstract = {In our previous culture-independent study on smokeless tobacco products, we have observed a strong positive correlation between several bacteria and genes involved in nitrate/nitrite reduction, biofilm formation, and pro-inflammation. Therefore, the present investigation was carried out to analyze the inhabitant bacterial population of the Indian ST products for assessing the health-associated risk attributes using culture-dependent approach. Traditional cultivation approaches recovered several bacterial isolates from commercial ST products on different culture media. A high colony formation unit (CFU) count was observed that ranged from 173 × 10[4] to 630.4 × 10[5] per gram of ST products. Of the 74 randomly selected and distinct bacterial isolates, 17 isolates showed a significantly enhanced growth (p-value < 0.05) in the presence of the aqueous tobacco extract. On biochemical characterization, these bacteria were identified as the member of Bacillus, Enterobacter, Micrococcus, Providencia, Serratia, Pantoea, Proteus, and Pseudomonas. Most of these bacteria also exhibited biofilm-forming activity, where eight bacterial isolates were identified for strong biofilm-forming action. 16S rRNA-based molecular characterization of these bacteria identified them as Bacillus subtilis, Bacillus paralicheniformis, Enterobacter sp., Serratia marcescens, Pantoea anthophila, and Enterobacter cloacae. Moreover, these bacteria also exhibited the potential to withstand high salt and heavy metal concentrations. The findings demonstrate that Indian ST products are heavily populated with wide bacterial species exhibiting potential in biofilm formation, heavy metal resistance, and salt tolerance.}, } @article {pmid37610246, year = {2023}, author = {She, W and Cheng, A and Ye, W and Zeng, P and Wang, H and Qian, PY}, title = {Mode of action of antimicrobial agents albofungins in eradicating penicillin- and cephalosporin-resistant Vibrio parahaemolyticus biofilm.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0156323}, doi = {10.1128/spectrum.01563-23}, pmid = {37610246}, issn = {2165-0497}, abstract = {Albofungin is a promising broad-spectrum antimicrobial compound against multidrug-resistant bacteria. In the present study, we further investigated albofungin's biofilm eradication activity and its potential mode of action against drug-resistant Vibrio parahaemolyticus. Among all derivatives, albofungin exhibited the best antibiofilm and antibacterial activity with rapid killing effects at 0.12 µg mL[-1]. Confocal microscopy observation exhibited that albofungin disrupted V. parahaemolyticus biofilms by killing or dispersing biofilm cells. Meanwhile, scanning electron microscope and fluorescent staining experiments demonstrated that albofungin rapidly destroyed the integrity and permeability of the bacterial cell membrane. Moreover, this study revealed an antibiofilm mechanism of albofungin involving inhibition of peptidoglycan biosynthesis, flagella assembly pathways, and secretion system proteins in V. parahaemolyticus by quantitative proteomics and validation experiments. Our results highlighted albofungin's mechanism of action in planktonic cells and biofilms and suggested further development and potential applications of albofungin for treating infections caused by penicillins-and-cephalosporins-resistant V. parahaemolyticus. IMPORTANCE Infections caused by multidrug-resistant bacteria, as well as a scarcity of new antibiotics, have become a major health threat worldwide. To tackle the demand for new and effective treatments, we investigated the mechanism of action of albofungin, a natural product derived from Streptomyces, which exhibits potent antimicrobial activity against multidrug-resistant bacteria. Albofungin showed potent biofilm eradication activity against penicillins-and-cephalosporins-resistant Vibrio parahaemolyticus, which expresses a novel metallo-β-lactamase and, thus, reduces their sensitivity to various antibiotics. We observed membrane disruption and permeation mechanisms in planktonic cells and biofilms after albofungin treatment, while albofungin had a weak interaction with bacterial DNA. Moreover, the antibiofilm mechanism of albofungin included inhibition of peptidoglycan biosynthesis, flagellar assembly pathways, and secretion system proteins. Our finding suggested potential applications of albofungin as an antibacterial and antibiofilm therapeutic agent.}, } @article {pmid37610010, year = {2023}, author = {Anantharaman, S and Guercio, D and Mendoza, AG and Withorn, JM and Boon, EM}, title = {Negative regulation of biofilm formation by nitric oxide sensing proteins.}, journal = {Biochemical Society transactions}, volume = {}, number = {}, pages = {}, doi = {10.1042/BST20220845}, pmid = {37610010}, issn = {1470-8752}, abstract = {Biofilm-based infections pose a serious threat to public health. Biofilms are surface-attached communities of microorganisms, most commonly bacteria and yeast, residing in an extracellular polymeric substance (EPS). The EPS is composed of several secreted biomolecules that shield the microorganisms from harsh environmental stressors and promote antibiotic resistance. Due to the increasing prominence of multidrug-resistant microorganisms and a decreased development of bactericidal agents in clinical production, there is an increasing need to discover alternative targets and treatment regimens for biofilm-based infections. One promising strategy to combat antibiotic resistance in biofilm-forming bacteria is to trigger biofilm dispersal, which is a natural part of the bacterial biofilm life cycle. One signal for biofilm dispersal is the diatomic gas nitric oxide (NO). Low intracellular levels of NO have been well documented to rapidly disperse biofilm macrostructures and are sensed by a widely conserved NO-sensory protein, NosP, in many pathogenic bacteria. When bound to heme and ligated to NO, NosP inhibits the autophosphorylation of NosP's associated histidine kinase, NahK, reducing overall biofilm formation. This reduction in biofilm formation is regulated by the decrease in secondary metabolite bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). The NosP/NahK signaling pathway is also associated with other major regulatory systems in the maturation of bacterial biofilms, including virulence and quorum sensing. In this review, we will focus on recent discoveries investigating NosP, NahK and NO-mediated biofilm dispersal in pathogenic bacteria.}, } @article {pmid37609283, year = {2023}, author = {Griend, JAV and Isenberg, RY and Kotla, KR and Mandel, MJ}, title = {Transcriptional pathways across colony biofilm models in the symbiont Vibrio fischeri.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.08.07.552283}, pmid = {37609283}, abstract = {UNLABELLED: Beneficial microbial symbionts that are horizontally acquired by their animal hosts undergo a lifestyle transition from free-living in the environment to associated with host tissues. In the model symbiosis between the Hawaiian bobtail squid and its microbial symbiont Vibrio fischeri, one mechanism used to make this transition during host colonization is the formation of biofilm-like aggregates in host mucosa. Previous work identified factors that are sufficient to induce V. fischeri biofilm formation, yet much remains unknown regarding the breadth of target genes induced by these factors. Here, we probed two widely-used in vitro models of biofilm formation to identify novel regulatory pathways in the squid symbiont V. fischeri ES114. We discovered a shared set of 232 genes that demonstrated similar patterns in expression in both models. These genes comprise multiple exopolysaccharide loci that are upregulated and flagellar motility genes that are downregulated, with a consistent decrease in measured swimming motility. Furthermore, we identified genes regulated downstream of the key sensor kinase RscS that are induced independent of the response regulator SypG. Our data suggest that putative response regulator VpsR plays a strong role in expression of at least a subset of these genes. Overall, this study adds to our understanding of the genes involved in V. fischeri biofilm regulation, while revealing new regulatory pathways branching from previously characterized signaling networks.

IMPORTANCE: The V. fischeri- squid system provides an opportunity to study biofilm development both in the animal host and in culture-based biofilm models that capture key aspects of in vivo signaling. In this work, we report the results of the transcriptomic profiling of two V. fischeri biofilm models followed by phenotypic validation and examination of novel signaling pathway architecture. Remarkable consistency between the models provides a strong basis for future studies using either-or both-approaches. A subset of the factors identified by the approaches were validated in the work, and the body of transcriptomic data provides a number of leads for future studies in culture and during animal colonization.}, } @article {pmid37608821, year = {2023}, author = {Li, Z}, title = {Response on Article "A Sustained-Release Nanosystem with MRSA Biofilm-Dispersing and -Eradicating Abilities Accelerates Diabetic Ulcer Healing" [Response to Letter].}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {4681-4682}, doi = {10.2147/IJN.S434825}, pmid = {37608821}, issn = {1178-2013}, } @article {pmid37609478, year = {2021}, author = {Kanakaris, NK and Giannoudis, PV}, title = {Biofilm and its implications postfracture fixation: All I need to know.}, journal = {OTA international : the open access journal of orthopaedic trauma}, volume = {4}, number = {3 Suppl}, pages = {}, pmid = {37609478}, issn = {2574-2167}, abstract = {Biofilm represents an organized multicellular community of bacteria having a complex 3D structure, formed by bacterial cells and their self-produced extracellular matrix. It usually attaches to any foreign body or fixation implant. It acts as a physical protective barrier of the bacteria from the penetration of antibodies, bacteriophages, granulocytes and biocides, antiseptics, and antibiotics. Biofilm-related infections will increase in the near future. This group of surgical site infections is the most difficult to diagnose, to suppress, to eradicate, and in general to manage. Multispecialty teams involved in all stages of care are an effective way to improve results and save resources and time for the benefit of patients and the health system. Significant steps have occurred recently in the prevention and development of clever tools that we can employ in this everlasting fight with the bacteria. Herein, we attempt to describe the nature and role of the "biofilm" to the specific clinical setting of surgical site infections in the field of orthopaedic trauma surgery.}, } @article {pmid37606707, year = {2023}, author = {Kharga, K and Dhar, I and Kashyap, S and Sengupta, S and Kumar, D and Kumar, L}, title = {Correction: Zingerone inhibits biofilm formation and enhances antibiotic efficacy against Salmonella biofilm.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {10}, pages = {285}, doi = {10.1007/s11274-023-03726-w}, pmid = {37606707}, issn = {1573-0972}, } @article {pmid37605758, year = {2023}, author = {Xiao, J and Su, L and Huang, S and Liu, L and Ali, K and Chen, Z}, title = {Epidemic Trends and Biofilm Formation Mechanisms of Haemophilus influenzae: Insights into Clinical Implications and Prevention Strategies.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {5359-5373}, pmid = {37605758}, issn = {1178-6973}, abstract = {Haemophilus influenzae (H. influenzae) is a significant pathogen responsible for causing respiratory tract infections and invasive diseases, leading to a considerable disease burden. The Haemophilus influenzae type b (Hib) conjugate vaccine has notably decreased the incidence of severe infections caused by Hib strains, and other non-typable H. influenzae (NTHi) serotypes have emerged as epidemic strains worldwide. As a result, the global epidemic trends and antibiotic resistance characteristics of H. influenzae have been altered. Researches on the virulence factors of H. influenzae, particularly the mechanisms underlying biofilm formation, and the development of anti-biofilm strategies hold significant clinical value. This article provides a summary of the epidemic trends, typing methods, virulence factors, biofilm formation mechanisms, and prevention strategies of H. influenzae. The increasing prevalence of NTHi strains and antibiotic resistance among H. influenzae, especially the high β-lactamase positivity and the emergence of BLNAR strains have increased clinical difficulties. Understanding its virulence factors, especially the formation mechanism of biofilm, and formulating effective anti-biofilm strategies may help to reduce the clinical impact. Therefore, future research efforts should focus on developing new approaches to prevent and control H. influenzae infections.}, } @article {pmid37604340, year = {2023}, author = {Mishra, S and Cheng, L and Lian, Y}, title = {Response of biofilm-based systems for antibiotics removal from wastewater: Resource efficiency and process resiliency.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139878}, doi = {10.1016/j.chemosphere.2023.139878}, pmid = {37604340}, issn = {1879-1298}, abstract = {Biofilm-based systems have efficient stability to cope-up influent shock loading with protective and abundant microbial assemblage, which are extensively exploited for biodegradation of recalcitrant antibiotics from wastewater. The system performance is subject to biofilm types, chemical composition, growth and thickness maintenance. The present study elaborates discussion on different type of biofilms and their formation mechanism involving extracellular polymeric substances secreted by microbes when exposed to antibiotics-laden wastewater. The biofilm models applied for estimation/prediction of biofilm-based systems performance are explored to classify the application feasibility. Further, the critical review of antibiotics removal efficiency, design and operation of different biofilm-based systems (e.g. rotating biological contactor, membrane biofilm bioreactor etc.) is performed. Extending the information on effect of various process parameters (e.g. hydraulic retention time, pH, biocarrier filling ratio etc.), the microbial community dynamics responsible of antibiotics biodegradation in biofilms, the technological problems, related prospective and key future research directions are demonstrated. The biofilm-based system with biocarriers filling ratio of ∼50-70% and predominantly enriched with bacterial species of phylum Proteobacteria protected under biofilm thickness of ∼1600 μm is effectively utilized for antibiotic biodegradation (>90%) when operated at DO concentration ≥3 mg/L. The C/N ratio ≥1 is best suitable condition to eliminate antibiotic pollution from biofilm-based systems. Considering the significance of biofilm-based systems, this review study could be beneficial for the researchers targeting to develop sustainable biofilm-based technologies with feasible regulatory strategies for treatment of mixed antibiotics-laden real wastewater.}, } @article {pmid37601561, year = {2023}, author = {Gerges, MA and Fahmy, YA and Hosny, T and Gandor, NH and Mohammed, SY and Mohamed, TMA and Abdelmoteleb, NEM and Esmaeel, NE}, title = {Biofilm Formation and Aspartyl Proteinase Activity and Their Association with Azole Resistance Among Candida albicans Causing Vulvovaginal Candidiasis, Egypt.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {5283-5293}, pmid = {37601561}, issn = {1178-6973}, abstract = {BACKGROUND: Candida albicans (C. albicans) is a major cause of vulvovaginal candidiasis (VVC), a condition that is commonly treated with azole agents. Biofilm formation and aspartyl proteinase production are important virulence factors that could be linked to azole resistance in C. albicans impeding therapy.

AIM: To find out the association of both factors with azole resistance among C. albicans isolated from VVC cases in Egyptian nonpregnant women of childbearing age.

PATIENTS AND METHODS: In a cross-sectional study, C. albicans was isolated from nonpregnant females diagnosed clinically as having VVC during a 1-year study period. Susceptibility to azole agents was tested using the disc diffusion method. Biofilm formation and aspartyl proteinase production were assessed phenotypically. Additionally, two biofilm-related genes (ALS1 and HWP1) and three proteinase genes (SAP2, SAP4, and SAP6) were screened for using polymerase chain reaction (PCR).

RESULTS: Among 204 C. albicans isolates, azole resistance ratios were as follows: voriconazole (30.4%), itraconazole (17.6%), fluconazole (11.3%) and econazole (6.4%). Biofilm-producing capacity was detected in 63.2% of isolates, and 63.2% were proteinase producers. The frequencies of ALS1 and HWP1 were 69.6% and 74.5%, respectively, while SAP2, SAP4, and SAP6 were 69.2%, 88.7%, and 64.7%, respectively. Biofilm formation was significantly associated with azole resistance (P < 0.001 for each tested azole agent) as was proteinase production (P < 0.001 for fluconazole, voriconazole, and econazole resistance and P = 0.047 for itraconazole).

CONCLUSION: Among nonpregnant Egyptian women of childbearing age, azole resistance in C. albicans causing VVC is significantly associated with biofilm formation and proteinase production. The development of new therapeutic agents that can target these factors is warranted.}, } @article {pmid37600954, year = {2023}, author = {Tiwari, V}, title = {Editorial: ESKAPE biofilm: challenges and solutions.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1253439}, pmid = {37600954}, issn = {2235-2988}, } @article {pmid37600945, year = {2023}, author = {Catania, AM and Di Ciccio, P and Ferrocino, I and Civera, T and Cannizzo, FT and Dalmasso, A}, title = {Evaluation of the biofilm-forming ability and molecular characterization of dairy Bacillus spp. isolates.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1229460}, pmid = {37600945}, issn = {2235-2988}, abstract = {Food processing lines represents a suitable environment for bacterial biofilm formation. One of the most common biofilm-forming genera in dairy processing plants is Bacillus, which includes species that may have a negative impact on safety and/or quality of dairy products. In the current study, we evaluated the biofilm forming ability and molecular characteristics of dairy Bacillus spp. isolates (B. cereus and B. subtilis). Reference strains (B. cereus ATCC 14579 and B. subtilis NCTC 3610) were also included in the experiment. All isolates were screened by micro-titer plate (96 wells) to assess their ability to form biofilm. Then, they were tested on two common food contact surfaces (polystyrene and stainless steel) by using 6-well plates and AISI 316 stainless steel coupons. Biofilm formation, expressed as biofilm production index (BPI), was higher on polystyrene than stainless steel (except for B. cereus ATCC 14579). These observations were further confirmed by scanning electron microscopy, which allowed the microscopy observation of biofilm structure. Moreover, a possible correlation among total viable cell counts (CFU) and BPI was examined, as well as a connection among biofilm formation and bacterial cell hydrophobicity. Finally, whole genome sequencing was performed highlighting a genetic similarity among the strains belonging to the same species. The presence of selected genes involved in biofilm formation was also examined showing that strains with a greater presence of these genes were able to produce more biofilm in the tested materials. Additionally, for B. cereus strains enterotoxin genes were detected.}, } @article {pmid37600120, year = {2023}, author = {Panjaitan, NSD and Hartanti, MD and Rinendyaputri, R}, title = {Response on Article "A Sustained-Release Nanosystem with MRSA Biofilm-Dispersing and -Eradicating Abilities Accelerates Diabetic Ulcer Healing" [Letter].}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {4633-4634}, pmid = {37600120}, issn = {1178-2013}, } @article {pmid37599629, year = {2023}, author = {Rahman, MA and Ashrafudoulla, M and Akter, S and Park, SH and Ha, SD}, title = {Probiotics and biofilm interaction in aquaculture for sustainable food security: A review and bibliometric analysis.}, journal = {Critical reviews in food science and nutrition}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/10408398.2023.2249114}, pmid = {37599629}, issn = {1549-7852}, abstract = {Aquaculture is one of the most significant food sources from the prehistoric period. As aquaculture intensifies globally, the prevalence and outbreaks of various pathogenic microorganisms cause fish disease and heavy mortality, leading to a drastic reduction in yield and substantial economic loss. With the modernization of the aquaculture system, a new challenge regarding biofilms or bacterial microenvironments arises worldwide, which facilitates pathogenic microorganisms to survive under unfavorable environmental conditions and withstand various treatments, especially antibiotics and other chemical disinfectants. However, we focus on the mechanistic association between those microbes which mainly form biofilm and probiotics in one of the major food production systems, aquaculture. In recent years, probiotics and their derivatives have attracted much attention in the fisheries sector to combat the survival strategy of pathogenic bacteria. Apart from this, Bibliometric analysis provides a comprehensive overview of the published literature, highlighting key research themes, emerging topics, and areas that require further investigation. This information is valuable for researchers, policymakers, and stakeholders in determining research priorities and allocating resources effectively.}, } @article {pmid37599501, year = {2023}, author = {Iqra Rasheed, - and Shagufta Riaz, - and Seema Shafique, -}, title = {Seaweed as natural raw material for industrial applications; extraction, physio-chemical characterization and antioxidant potential of alginate based biofilm.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {36}, number = {4}, pages = {1241-1248}, pmid = {37599501}, issn = {1011-601X}, abstract = {Brown seaweed Jolyna laminarioides was collected during low tide from coastal area of Karachi and was used as renewable source for production of sodium alginate. Starch was mixed with alginate as secondary polymer along with high (30%) and low (15%) concentration of bio-plasticizer (sorbitol and glycerol) to produce an eco-friendly biofilm by casting technique. Thickness, moisture content, solubility, bio-degradation test, density, scanning electron microscopy (SEM), Fourier transform infra-red spectroscopy (FTIR) and DPPH (2,2-diphenyl picrylhydrazyl) assay was performed for each blend of biofilm. The obtained results showed the affinity of sorbitol and glycerol with alginate-starch matrix with significant moisture content, thickness and biodegradation properties. The antioxidative potential of alginate based biofilms make it suitable for pharmaceutical and cosmeceutical applications like bio-packaging and manufacturing of eco-friendly production.}, } @article {pmid37598946, year = {2023}, author = {Valdés, ME and Rodríguez, CMC and Santos, LHMLM and Barceló, D and Giorgi, ADN and Rodríguez-Mozaz, S and Amé, MV}, title = {Contaminants of emerging concern fate and fluvial biofilm status as pollution markers in an urban river.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139837}, doi = {10.1016/j.chemosphere.2023.139837}, pmid = {37598946}, issn = {1879-1298}, abstract = {Contaminants of emerging concern (CEC) are still under research given the vast diversity of compounds reaching freshwater ecosystems and adverse effects they might cause. In this study, the environmental fate of 73 CEC, comprising sweeteners, stimulants and several pharmaceutical therapeutic classes, and changes in fluvial biofilm photosynthetic parameters were evaluated in a semi-arid urban river receiving diffuse and point sources of pollution (Suquía river, Argentina). Out of the 37 CEC detected, 30 were quantified in surface water (n.d. - 9826 ng/L), 10 in biofilm (n.d. - 204 ng/gd.w.) and 9 in the clay fraction of sediments (n.d. - 64 ng/gd.w.). CEC distribute differently among the 3 matrices: water phase presents the biggest diversity of compounds (14 CEC families), being analgesic/anti-inflammatories the most abundant family. Antibiotics largely predominated in biofilms (7 CEC families), while the stimulant caffeine and some antibiotics where the most abundant in sediments (6 CEC families). Different CEC accumulated in biofilms and sediments upstream and downstream the city, and big shifts of biofilm community occurred downstream WWTP. The shift of biofilm community upstream (F0 > 0) and downstream the WWTP (F0 = 0) shows a sensitive response of F0 to the impact of WWTP. Biofilm photosynthetic parameters responded in less impacted urban sites (sites 1, 2 and 3), where significant correlations were found between ketoprofen and some antibiotics and biofilm parameters. The diversity and amount of CEC found in the urban section of Suquía river alert to the magnitude of point and non-point sources of pollution.}, } @article {pmid37598804, year = {2023}, author = {Feng, L and Wu, G and Zhang, Z and Tian, Z and Li, B and Cheng, J and Yang, G}, title = {Improving denitrification performance of biofilm technology with salt-tolerant denitrifying bacteria agent for treating high-strength nitrate and sulfate wastewater from lab-scale to pilot-scale.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129696}, doi = {10.1016/j.biortech.2023.129696}, pmid = {37598804}, issn = {1873-2976}, abstract = {This study focused on the application of salt-tolerant denitrifying bacteria (DBA) in an optimized biofilm process to treat high sulfate-nitrate wastewater from lab scale to pilot scale. Lab scale results demonstrated the salinity, DBA inoculum, supplementary carbon and phosphorus source significantly varied the startup periods at the range of 36-74 d, and the optimum initial start-up conditions were as follows: >0.6 g/L of DBA, 2-4 of C/N ratio, 0.3-0.6 mg/L of phosphorus and a salinity-gradient domestication method. A pilot scale of biofilm technology with DBA was further developed for treating real wastewater from the desulfuration and denitration with both high nitrate (≈200 mg/L) and sulfate (2.7%). The denitrification efficiency reached above 90% after one-month gradient-salinity of 0.5%-2.7%. Mature biofilm had dominant genera Hyphomicrobium (31.80%-61.35%), Methylotenera (0.85%-20.21%) and Thauera (1.42%-8.40%), etc. Notably, the largest genera Hyphomicrobium covered the complete denitrification genes.}, } @article {pmid37596603, year = {2023}, author = {Khan, MM and Ali, A and Kolenda, R and Olowe, OA and Weinreich, J and Li, G and Schierack, P}, title = {The role of AJB35136 and fdtA genes in biofilm formation by avian pathogenic Escherichia coli.}, journal = {BMC veterinary research}, volume = {19}, number = {1}, pages = {126}, pmid = {37596603}, issn = {1746-6148}, abstract = {BACKGROUND: Infections caused by avian pathogenic Escherichia coli (APEC) result in significant economic losses in poultry industry. APEC strains are known to form biofilms in various conditions allowing them to thrive even under harsh and nutrient-deficient conditions on different surfaces, and this ability enables them to evade chemical and biological eradication methods. Despite knowing the whole genome sequences of various APEC isolates, little has been reported regarding their biofilm-associated genes. A random transposon mutant library of the wild-type APEC IMT 5155 comprising 1,300 mutants was analyzed for biofilm formation under nutrient deprived conditions using Videoscan technology coupled with fluorescence microscopy. Seven transposon mutants were found to have reproducibly and significantly altered biofilm formation and their mutated genes were identified by arbitrary PCR and DNA sequencing. The intact genes were acquired from the wild-type strain, cloned in pACYC177 plasmid and transformed into the respective altered biofilm forming transposon mutants, and the biofilm formation was checked in comparison to the wild type and mutant strains under the same conditions.

RESULTS: In this study, we report seven genes i.e., nhaA, fdeC, yjhB, lysU, ecpR, AJB35136 and fdtA of APEC with significant contribution to biofilm formation. Reintroduction of AJB35136 and fdtA, reversed the altered phenotype proving that a significant role being played by these two O-antigen related genes in APEC biofilm formation. Presence of these seven genes across nonpathogenic E. coli and APEC genomes was also analyzed showing that they are more prevalent in the latter.

CONCLUSIONS: The study has elucidated the role of these genes in APEC biofilm formation and compared them to adhesion expanding the knowledge and understanding of the economically significant pathogens.}, } @article {pmid37596435, year = {2023}, author = {Babaeekhou, L and Ghane, M and Mohammad Rafiee, M}, title = {Photodynamic Therapy and Its Synergism with Melittin Against Drug-Resistant Acinetobacter baumannii Isolates with High Biofilm Formation Ability.}, journal = {Current microbiology}, volume = {80}, number = {10}, pages = {324}, pmid = {37596435}, issn = {1432-0991}, abstract = {Drug-resistant biofilm producer A. baumannii isolates are a global concern that warns researchers about the development of new treatments. This study was designed to analyze the effect of photodynamic therapy (PDT) as monotherapy and associated with melittin on multidrug-resistant A. baumannii isolates. Sub-lethal doses of photosensitizer, LED, and PDT were determined. The PDT effect on the biofilm and expression of biofilm-associated genes was evaluated by scanning electron microscopy and quantitative real-time PCR (qRT-PCR) methods, respectively. The synergistic effect of PDT and melittin on the survival of MDR/XDR strong biofilm producer isolates was evaluated by checkerboard assay. Survival rates were significantly decreased at the lowest concentration of 12.5-50 μg/ml in 4 min at an energy density of 93.75 J/cm[2] (P < 0.05). The optimized PDT method had a bactericidal effect against all tested groups, and the mean expression levels of csu, abaI, bap, and ompA genes in the strong biofilm producers were decreased significantly compared to the control group. The combined effect of LED and melittin successfully reduced the MDR/XDR A. baumannii strong biofilm producers' growth from 3.1 logs. MB-mediated aPDT and combined treatment of PDT with melittin, which has been investigated for the first time in this study, can be an efficient strategy against MDR/XDR A. baumannii isolates with strong biofilm production capacity.}, } @article {pmid37596397, year = {2023}, author = {Zheng, X and Gao, M and Wu, L and Lu, X and Lin, Q and Zhong, H and Lu, Y and Zhang, Y and Zhang, X}, title = {Ceftazidime-assisted synthesis of ultrasmall chitosan nanoparticles for biofilm penetration and eradication of Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {13481}, pmid = {37596397}, issn = {2045-2322}, support = {81971726//National Natural Science Foundation of China/ ; YKK20191//Nanjing Healthcare Science and Technology Development Special Funded Project/ ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) infections present a grave threat to immunocompromised individuals, particularly those with cystic fibrosis due to the development of bacterial biofilms. In this study, we engineered self-assembling chitosan-ceftazidime nanoparticles (CSCE) capable of effectively penetrating biofilms and eradicating P. aeruginosa. The CSCE nanoparticles were synthesized through ionic cross-linking, combining negatively charged ceftazidime with positively charged chitosan, resulting in uniform nanoparticles measuring approximately 40 nm in diameter, exhibiting high dispersity and excellent biocompatibility. Remarkably, these nanoparticles exhibited significant inhibition of P. aeruginosa growth, reduced pyocyanin production, and diminished biofilm formation, achieving a maximum inhibition rate of 22.44%. Furthermore, in vivo investigations demonstrated enhanced survival in mice with abdominal P. aeruginosa infection following treatment with CSCE nanoparticles, accompanied by reduced levels of inflammatory cytokines Interleukin-6 (125.79 ± 18.63 pg/mL), Interleukin-17 (125.67 ± 5.94 pg/mL), and Tumor Necrosis Factor-α (135.4 ± 11.77 pg/mL). Critically, mice treated with CSCE nanoparticles showed no presence of bacteria in the bloodstream following intraperitoneal P. aeruginosa infection. Collectively, our findings highlight the potential of these synthesized nanoparticles as effective agents against P. aeruginosa infections.}, } @article {pmid37596293, year = {2023}, author = {Astasov-Frauenhoffer, M and Göldi, L and Rohr, N and Worreth, S and Dard, E and Hünerfauth, S and Töpper, T and Zurflüh, J and Braissant, O}, title = {Antimicrobial and mechanical assessment of cellulose-based thermoformable material for invisible dental braces with natural essential oils protecting from biofilm formation.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {13428}, pmid = {37596293}, issn = {2045-2322}, support = {101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; 101.335 IP-LS//Innosuisse - Schweizerische Agentur für Innovationsförderung/ ; }, abstract = {Controlling biofilm formation in the oral cavity during orthodontic treatments is crucial. Therefore, antimicrobial surfaces for invisible dental appliances are of interest to both therapists and patients. Here we present a cellulose-based thermoformable material used for invisible braces that can be loaded with essential oils (EOs) having antibacterial and antifungal properties. We hypothesize that this material can absorb and release EOs, thus providing an antimicrobial effect without compromising the safety and mechanical properties necessary for dental invisible braces. Conventional microbiology and isothermal microcalorimetry analyses revealed that the thermoformable material loaded with essential oils significantly delayed the biofilm formation of oral streptococci (S. mutans and S. mitis) under static conditions (p < 0.05) and while simulating saliva flow (p < 0.05). In addition, cytotoxicity tests (ISO 10993-5), revealed that the loaded material is well tolerated by human gingival fibroblasts. Finally, the loading with antibacterial agents did not significantly alter the mechanical properties and stability of the material (initial force (p = 0.916); initial stress (p = 0.465)). Compared to gold-standard clear aligner materials, this material offers a reliable transmission of forces for orthodontic treatments. Moreover, this approach exhibits the potential for acting as an oral drug delivery platform for multiple compounds.}, } @article {pmid37595876, year = {2023}, author = {Enriquez, KT and Plummer, WD and Neufer, PD and Chazin, WJ and Dupont, WD and Skaar, EP}, title = {Temporal modelling of the biofilm lifecycle (TMBL) establishes kinetic analysis of plate-based bacterial biofilm dynamics.}, journal = {Journal of microbiological methods}, volume = {}, number = {}, pages = {106808}, doi = {10.1016/j.mimet.2023.106808}, pmid = {37595876}, issn = {1872-8359}, abstract = {Bacterial biofilms are critical to pathogenesis and infection. They are associated with rising rates of antimicrobial resistance. Biofilms are correlated with worse clinical outcomes, making them important to infectious diseases research. There is a gap in knowledge surrounding biofilm kinetics and dynamics which makes biofilm research difficult to translate from bench to bedside. To address this gap, this work employs a well-characterized crystal violet biomass accrual and planktonic cell density assay across a clinically relevant time course and expands statistical analysis to include kinetic information in a protocol termed the TMBL (Temporal Mapping of the Biofilm Lifecycle) assay. TMBL's statistical framework quantitatively compares biofilm communities across time, species, and media conditions in a 96-well format. Measurements from TMBL can reliably be condensed into response features that inform the time-dependent behavior of adherent biomass and planktonic cell populations. Staphylococcus aureus and Pseudomonas aeruginosa biofilms were grown in conditions of metal starvation in nutrient-variable media to demonstrate the rigor and translational potential of this strategy. Significant differences in single-species biofilm formation are seen in metal-deplete conditions as compared to their controls which is consistent with the consensus literature on nutritional immunity that metal availability drives transcriptomic and metabolomic changes in numerous pathogens. Taken together, these results suggest that kinetic analysis of biofilm by TMBL represents a statistically and biologically rigorous approach to studying the biofilm lifecycle as a time-dependent process. In addition to current methods to study the impact of microbe and environmental factors on the biofilm lifecycle, this kinetic assay can inform biological discovery in biofilm formation and maintenance.}, } @article {pmid37594661, year = {2023}, author = {Ali, SA and Chung, KHK and Forgham, H and Olsen, WP and Kakinen, A and Balaji, A and Otzen, DE and Davis, TP and Javed, I}, title = {Alzheimer's Progenitor Amyloid-β Targets and Dissolves Microbial Amyloids and Impairs Biofilm Function.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2301423}, doi = {10.1002/advs.202301423}, pmid = {37594661}, issn = {2198-3844}, support = {APP2009991//NHMRC/ ; APP1197373//NHMRC/ ; 8021-00208B//Independent Danish Research Council | Natural Sciences/ ; //Sino-Danish Center/ ; }, abstract = {Alzheimer's disease (AD) is a leading form of dementia where the presence of extra-neuronal plaques of Amyloid-β (Aβ) is a pathological hallmark. However, Aβ peptide is also observed in the intestinal tissues of AD patients and animal models. In this study, it is reported that Aβ monomers can target and disintegrate microbial amyloids of FapC and CsgA formed by opportunistic gut pathogens, Pseudomonas aeruginosa and Escherichia coli, explaining a potential role of Aβ in the gut-brain axis. Employing a zebrafish-based transparent in vivo system and whole-mount live-imaging, Aβ is observed to diffuse into the vasculature and subsequently localize with FapC or CsgA fibrils that were injected into the tail muscles of the fish. FapC aggregates, produced after Aβ treatment (Faβ), present selective toxicity to SH-SY5Y neuronal cells while the intestinal Caco-2 cells are shown to phagocytose Faβ in a non-toxic cellular process. After remodeling by Aβ, microbial fibrils lose their native function of cell adhesion with intestinal Caco-2 cells and Aβ dissolves and detachs the microbial fibrils already attached to the cell membrane. Taken together, this study strongly indicates an anti-biofilm role for Aβ monomers that can help aid in the future development of selective anti-Alzheimer's and anti-infective medicine.}, } @article {pmid37594291, year = {2023}, author = {Ullah, MA and Islam, MS and Rana, ML and Ferdous, FB and Neloy, FH and Punom, SA and Hassan, J and Rahman, MT}, title = {Draft genome sequence of biofilm-forming Enterococcus faecalis BAU_Ef01 strain isolated from shrimp (Penaeus indicus) in Bangladesh.}, journal = {Microbiology resource announcements}, volume = {}, number = {}, pages = {e0055123}, doi = {10.1128/MRA.00551-23}, pmid = {37594291}, issn = {2576-098X}, abstract = {Here, we sequence and analyze a biofilm-forming strain of Enterococcus faecalis BAU_Ef01 isolated from a shrimp in Bangladesh. The whole genome of the strain had a length of 2,862,301 bp, 38 contigs, an average G+C content of 37.36%, 80.0× genome coverage, and 35 predicted antibiotic resistance and virulence genes each.}, } @article {pmid37593545, year = {2023}, author = {Flores-Vargas, G and Korber, DR and Bergsveinson, J}, title = {Sub-MIC antibiotics influence the microbiome, resistome and structure of riverine biofilm communities.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1194952}, pmid = {37593545}, issn = {1664-302X}, abstract = {The effects of sub-minimum inhibitory concentrations (sub-MICs) of antibiotics on aquatic environments is not yet fully understood. Here, we explore these effects by employing a replicated microcosm system fed with river water where biofilm communities were continuously exposed over an eight-week period to sub-MIC exposure (1/10, 1/50, and 1/100 MIC) to a mix of common antibiotics (ciprofloxacin, streptomycin, and oxytetracycline). Biofilms were examined using a structure-function approach entailing microscopy and metagenomic techniques, revealing details on the microbiome, resistome, virulome, and functional prediction. A comparison of three commonly used microbiome and resistome databases was also performed. Differences in biofilm architecture were observed between sub-MIC antibiotic treatments, with an overall reduction of extracellular polymeric substances and autotroph (algal and cyanobacteria) and protozoan biomass, particularly at the 1/10 sub-MIC condition. While metagenomic analyses demonstrated that microbial diversity was lowest at the sub-MIC 1/10 antibiotic treatment, resistome diversity was highest at sub-MIC 1/50. This study also notes the importance of benchmarking analysis tools and careful selection of reference databases, given the disparity in detected antimicrobial resistance genes (ARGs) identity and abundance across methods. Ultimately, the most detected ARGs in sub-MICs exposed biofilms were those that conferred resistance to aminoglycosides, tetracyclines, β-lactams, sulfonamides, and trimethoprim. Co-occurrence of microbiome and resistome features consistently showed a relationship between Proteobacteria genera and aminoglycoside ARGs. Our results support the hypothesis that constant exposure to sub-MICs antibiotics facilitate the transmission and promote prevalence of antibiotic resistance in riverine biofilms communities, and additionally shift overall microbial community metabolic function.}, } @article {pmid37587131, year = {2023}, author = {Flores, P and McBride, SA and Galazka, JM and Varanasi, KK and Zea, L}, title = {Biofilm formation of Pseudomonas aeruginosa in spaceflight is minimized on lubricant impregnated surfaces.}, journal = {NPJ microgravity}, volume = {9}, number = {1}, pages = {66}, pmid = {37587131}, issn = {2373-8065}, support = {80NSSC17K0036//National Aeronautics and Space Administration (NASA)/ ; 80NSSC21K1950//National Aeronautics and Space Administration (NASA)/ ; }, abstract = {The undesirable, yet inevitable, presence of bacterial biofilms in spacecraft poses a risk to the proper functioning of systems and to astronauts' health. To mitigate the risks that arise from them, it is important to understand biofilms' behavior in microgravity. As part of the Space Biofilms project, biofilms of Pseudomonas aeruginosa were grown in spaceflight over material surfaces. Stainless Steel 316 (SS316) and passivated SS316 were tested for their relevance as spaceflight hardware components, while a lubricant impregnated surface (LIS) was tested as potential biofilm control strategy. The morphology and gene expression of biofilms were characterized. Biofilms in microgravity are less robust than on Earth. LIS strongly inhibits biofilm formation compared to SS. Furthermore, this effect is even greater in spaceflight than on Earth, making LIS a promising option for spacecraft use. Transcriptomic profiles for the different conditions are presented, and potential mechanisms of biofilm reduction on LIS are discussed.}, } @article {pmid37586891, year = {2023}, author = {Thiroux, A and Labanowski, J and Venisse, N and Crapart, S and Boisgrollier, C and Linares, C and Berjeaud, JM and Villéger, R and Crépin, A}, title = {Exposure to endocrine disruptors promotes biofilm formation and contributes to increased virulence of Pseudomonas aeruginosa.}, journal = {Environmental microbiology reports}, volume = {}, number = {}, pages = {}, doi = {10.1111/1758-2229.13190}, pmid = {37586891}, issn = {1758-2229}, support = {80 Prime//Centre National de la Recherche Scientifique/ ; //European Regional Development Fund/ ; //State-Region Planning Contracts/ ; }, abstract = {Anthropogenic activities contribute to the spread of chemicals considered as endocrine disruptors (ED) in freshwater ecosystems. While several studies have reported interactions of EDs with organisms in those ecosystems, very few have assessed the effect of these compounds on pathogenic bacteria. Here we have evaluated the impact of five EDs found in aquatic resources on the virulence of human pathogen P. aeruginosa. ED concentrations in French aquatic resources of bisphenol A (BPA), dibutyl phthalate (DBP), ethylparaben (EP), methylparaben (MP) and triclosan (TCS) at mean molar concentration were 1.13, 3.58, 0.53, 0.69, and 0.81 nM respectively. No impact on bacterial growth was observed at EDs highest tested concentration. Swimming motility of P. aeruginosa decreased to 28.4% when exposed to EP at 100 μM. Swarming motility increased, with MP at 1 nM, 10 and 100 μM (1.5-fold); conversely, a decrease of 78.5%, with DBP at 100 μM was observed. Furthermore, exposure to 1 nM BPA, DBP and EP increased biofilm formation. P. aeruginosa adhesion to lung cells was two-fold higher upon exposure to 1 nM EP. We demonstrate that ED exposure may simultaneously decrease mobility and increase cell adhesion and biofilm formation, which may promote colonisation and establishment of the pathogen.}, } @article {pmid37584762, year = {2023}, author = {Kumar, G and Kallscheuer, N and Jogler, M and Wiegand, S and Heuer, A and Boedeker, C and Rohde, M and Jogler, C}, title = {Stratiformator vulcanicus gen. nov., sp. nov., a marine member of the family Planctomycetaceae isolated from a red biofilm in the Tyrrhenian Sea close to the volcanic island Panarea.}, journal = {Antonie van Leeuwenhoek}, volume = {}, number = {}, pages = {}, pmid = {37584762}, issn = {1572-9699}, support = {EXC 2051: Balance of the Microverse, project number 390713860//Deutsche Forschungsgemeinschaft/ ; KA 4967/1-1//Deutsche Forschungsgemeinschaft/ ; EXC 2051: Balance of the Microverse, project number 390713860//Deutsche Forschungsgemeinschaft/ ; }, abstract = {A novel planctomycetal strain, designated Pan189[T], was isolated from biofilm material sampled close to Panarea Island in the Tyrrhenian Sea. Cells of strain Pan189[T] are round grain rice-shaped, form pink colonies and display typical planctomycetal characteristics including asymmetric cell division through polar budding and presence of crateriform structures. Cells bear a stalk opposite to the division pole and fimbriae cover the cell surface. Strain Pan189[T] has a mesophilic (optimum at 24 °C) and neutrophilic (optimum at pH 7.5) growth profile, is aerobic and heterotrophic. Under laboratory-scale cultivation conditions, it reached a generation time of 102 h (µmax = 0.0068 h[-1]), which places the strain among the slowest growing members of the phylum Planctomycetota characterized so far. The genome size of the strain is with 5.23 Mb at the lower limit among the family Planctomycetaceae (5.1-8.9 Mb). Phylogenetically, the strain represents a novel genus and species in the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. We propose the name Stratiformator vulcanicus gen. nov., sp. nov. for the novel taxon, that is represented by the type strain Pan189[T] (= DSM 101711[ T] = CECT 30699[ T]).}, } @article {pmid37582447, year = {2023}, author = {Buakaew, T and Ratanatamskul, C}, title = {Effects of microaeration and sludge recirculation on VFA and nitrogen removal, membrane fouling reduction and microbial community of the anaerobic baffled biofilm-membrane bioreactor in treating building wastewater.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {166248}, doi = {10.1016/j.scitotenv.2023.166248}, pmid = {37582447}, issn = {1879-1026}, abstract = {A novel anaerobic baffled biofilm-membrane bioreactor (AnBB-MBR) with microaeration of 0.62 LO2/LFeed was developed to improve VFA and nitrogen removal from building wastewater. Three different membrane bioreactor systems- R1: AnBB-MBR (without microaeration); R2: AnBB-MBR with microaeration; and R3: AnBB-MBR with integrated microaeration and sludge recirculation- were operated in parallel at the same hydraulic retention time of 20 h and sludge retention time of 100 d. The microaeration promoted greater microbial richness and diversity, which could significantly enhance the removal of acetic acid and dissolved methane in the R2 and R3 systems. Moreover, the partial nitrification and the ability of anammox (Candidatus Brocadia) to thrive in R2 enabled NH4[+]-N removal to be enhanced by up to 57.8 %. The worst membrane fouling was found in R1 due to high amount of protein as well as fine particles (0.5-5.0 μm) acting as foulants that contributed to pore blocking. While the integration of sludge recirculation with microaeration in R3 was able to improve the membrane permeate flux slightly as compared to R2. Therefore, the AnBB-MBR integrated with a microaeration system (R2) can be considered as promising technology for building wastewater treatment when considering VFA and nutrient removal and an energy-saving approach with low aeration intensity.}, } @article {pmid37582431, year = {2023}, author = {Wang, Y and Xu, J and Yu, C and Zhou, X and Chang, L and Liu, J and Peng, Q}, title = {Prevention of bacterial biofilm formation on orthodontic brackets by non-crosslinked chitosan coating.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {126283}, doi = {10.1016/j.ijbiomac.2023.126283}, pmid = {37582431}, issn = {1879-0003}, abstract = {During orthodontic treatment, the patients are susceptible to dental caries as a result of the bacterial adhesion and biofilm formation around the orthodontic brackets. Prevention of the caries-related biofilm formation is of significance for maintaining both aesthetics and health of the teeth. Herein, the brackets were functionalized with antibacterial activity via coating a layer of non-crosslinked chitosan (CS). We firstly demonstrated the ability of free CS scaffolds (not coated on brackets) to inhibit the formation of Streptococcus mutans biofilms (inhibition rate 94.3 % for CS-0.3 mg) and to eradicate the mature biofilms (biofilm loss rate 99.8 % for CS-1.2 mg). Further, the inhibition of S. mutans biofilm formation on brackets by CS coating was investigated for the first time. As a result, the CS-coated brackets (Br-CS) kept the great biofilm inhibition capacity of free CS scaffolds. In detail, the Br-CS, prepared by immersing brackets in CS solutions (containing 1.0, 2.5, 5.0 and 10 mg/mL CS) and freeze-drying, showed the biofilm inhibition rate of 48.5 %, 88.6 %, 96.4 % and 99.6 %, respectively. In conclusion, coating orthodontic brackets with the non-crosslinked CS is a potential approach for inhibiting biofilm formation and protecting patients from dental caries.}, } @article {pmid37582708, year = {2023}, author = {Kalantar-Neyestanaki, D and Mansouri, S and Tadjrobehkar, O and Isaei, E}, title = {The frequency of adherence, biofilm-associated, Arginine Catabolic Mobile element genes, and biofilm formation in clinical and healthcare worker coagulase-negative staphylococci isolates.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {222}, pmid = {37582708}, issn = {1471-2180}, abstract = {BACKGROUND: Healthcare workers may pave the way for increased infections in hospitalized patients by coagulase-negative staphylococci (CoNS). Biofilm formation and antibiotic resistance are the major problems posed by CoNS in nosocomial infections. In this study, we determined biofilm production level and the distribution of biofilm-associated and virulence genes, including icaADBC, aap, bhp, atlE, embp, and fbe, as well as IS256, IS257, mecA, and ACME clusters (arc-A, opp-3AB) among 114 clinical (n = 57) and healthcare workers (n = 57) CoNS isolates in Kerman, Iran.

RESULTS: In this study, more than 80% (n = 96) of isolates were methicillin-resistant CoNS (MR-CoNS). Out of 114 isolates, 33% (n = 38) were strong biofilm producers. Strong biofilm formation was found to be significantly different between clinical and healthcare workers' isolates (P < 0.050). In addition, 28% (n = 32) of isolates were positive for icaADBC simultaneously, and all were strong biofilm producers. The prevalence of icaADBC, mecA, bhp, fbe, and IS256 in clinical isolates was higher than that in healthcare workers' isolates (P < 0.050). A significant relationship was observed between clinical isolates and the presence of icaADBC, mecA, bhp, and IS256. Although these elements were detected in healthcare workers' isolates, they were more frequent in clinical isolates compared to those of healthcare workers.

CONCLUSIONS: The high prevalence of ACME clusters in healthcare workers' isolates and biofilm formation of these isolates partially confirms the bacterial colonization in the skin of healthcare workers. Isolating MR-CoNS from healthcare workers' skin through similar genetic elements to clinical isolates, such as icaADBC, mecA, and IS256, calls for appropriate strategies to control and prevent hospital infections.}, } @article {pmid37580896, year = {2023}, author = {Roy, PK and Ha, AJ and Nahar, S and Hossain, MI and Ashrafudoulla, M and Toushik, SH and Mizan, MFR and Kang, I and Ha, SD}, title = {Inhibitory effects of vorinostat (SAHA) against food-borne pathogen Salmonella enterica serotype Kentucky mixed culture biofilm with virulence and quorum-sensing relative expression.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/08927014.2023.2242263}, pmid = {37580896}, issn = {1029-2454}, abstract = {Salmonella is a food-borne microorganism that is also a zoonotic bacterial hazard in the food sector. This study determined how well a mixed culture of Salmonella Kentucky formed biofilms on plastic (PLA), silicon rubber (SR), rubber gloves (RG), chicken skin and eggshell surfaces. In vitro interactions between the histone deacetylase inhibitor-vorinostat (SAHA)-and S. enterica serotype Kentucky were examined utilizing biofilms. The minimum inhibitory concentration (MIC) of SAHA was 120 µg mL[-1]. The addition of sub-MIC (60 µg mL[-1]) of SAHA decreased biofilm formation for 24 h on PLA, SR, RG, Chicken skin, and eggshell by 3.98, 3.84, 4.11, 2.86 and 3.01 log (p < 0.05), respectively. In addition, the initial rate of bacterial biofilm formation was higher on chicken skin than on other surfaces, but the inhibitory effect was reduced. Consistent with this conclusion, virulence genes expression (avrA, rpoS and hilA) and quorum-sensing (QS) gene (luxS) was considerably downregulated at sub-MIC of SAHA. SAHA has potential as an anti-biofilm agent against S. enterica serotype Kentucky biofilm, mostly by inhibiting virulence and quorum-sensing gene expression, proving the histone deacetylase inhibitor could be used to control food-borne biofilms in the food industry.}, } @article {pmid37580811, year = {2023}, author = {Luciani, L and Stefanetti, V and Rampacci, E and Gobbi, P and Valentini, L and Capuozzo, R and Passamonti, F}, title = {Comparison between clinical evaluations and laboratory findings and the impact of biofilm on antimicrobial susceptibility in vitro in canine otitis externa.}, journal = {Veterinary dermatology}, volume = {}, number = {}, pages = {}, doi = {10.1111/vde.13197}, pmid = {37580811}, issn = {1365-3164}, support = {//Società Italiana di Dermatologia Veterinaria/ ; }, abstract = {BACKGROUND: In canine otitis externa (OE), biofilm-producing bacteria are frequently present but biofilm may be underdiagnosed clinically.

HYPOTHESIS/OBJECTIVES: The study aimed to investigate an association between clinical and cytological findings with bacteriological data from dogs with OE, to establish, through Environmental Scanning Electron Microscope (ESEM) examination, whether the presence of biofilm in vivo can be predicted and to evaluate the impact of biofilm on antimicrobial susceptibility tests.

MATERIALS AND METHODS: Fifty-six dogs showing clinical signs of OE were enrolled. One cotton swab each was collected for ESEM, bacterial culture and susceptibility testing and for cytology. Staphylococcus pseudintermedius (n = 42, 48.8%) and Pseudomonas aeruginosa (n = 26, 30.2%) were tested for their ability to form biofilm. Minimum Inhibitory Concentrations (MIC), Minimal Biofilm Inhibitory Concentrations (MBIC) and Minimal Biofilm Eradication Concentrations (MBEC) towards enrofloxacin, gentamicin, polymyxin B and rifampicin were determined.

RESULTS: Pseudomonas aeruginosa was positively associated with the biofilm clinical evaluation (p < 0.01) and neutrophils (p < 0.05), nuclear streaks (p < 0.01) and rods bacteria (p < 0.01) on cytology. S. pseudintermedius was associated with a low presence of neutrophils. There was a statistical correlation between clinical and cytological biofilm presence (p ≤ 0.01), but none with the biofilm production assay nor ESEM biofilm detection. No differences were found comparing the results of MIC and MBIC. MBEC results showed higher values than MIC and MBIC for all antimicrobials tested (p ≤ 0.001).

Biofilm presence in OE was often underdiagnosed. Even if there is no specific clinical or cytological pattern related to biofilm, its presence should always be suspected.}, } @article {pmid37580170, year = {2023}, author = {Jiang, Y and Wang, P and Qu, M and Wang, T and Li, F and Wang, L and Yao, L}, title = {Effects of luxS gene on growth characteristics, biofilm formation and antimicrobial resistance of multi-antimicrobial resistant Vibrio parahaemolyticus Vp2015094 isolated from shellfish.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad172}, pmid = {37580170}, issn = {1365-2672}, abstract = {AIMS: Vibrio parahaemolyticus is an important foodborne pathogen worldwide which can cause gastroenteritis. This study aimed to investigate the effect of quorum sensing system LuxS/AI-2 related gene luxS on the biological characteristics and antimicrobial resistance of V. parahaemolyticus Vp2015094 from shellfish which carried a multi-antimicrobial resistant plasmid.

METHODS AND RESULTS: The critical gene luxS related to the synthesis of AI-2 in V. parahaemolyticus Vp2015094 was knocked out by homologous recombination with suicide plasmid. The effect of luxS on the biological characteristics of V. parahaemolyticus was determined by comparing the growth, AI-2 activity, motility, biofilm formation ability, and antibiotic resistance between the wildtype strain and the luxS deletion mutant. Compared with wildtype strain, the production of AI-2, the motility and biofilm formation ability, antimicrobial resistance and conjugation frequency of luxS deletion mutant strain were decreased. The transcriptome sequencing showed that the transcriptional levels of many genes related to motility, biofilm formation, antimicrobial resistance and conjugation were significantly down-regulated after luxS deletion.

CONCLUSIONS: Quorum sensing system LuxS/AI-2 related gene luxS in V. parahaemolyticus Vp2015094 played an important role in growth characteristics, biofilm formation, antimicrobial resistance and resistance genes' transfer.}, } @article {pmid37579620, year = {2023}, author = {Qin, M and Li, Y and Xu, W and Gao, W and Yin, S and Hu, X and Zhang, R and Ding, C}, title = {Spirooxindol alkaloids from Voacanga africana: Targeting biofilm of MBLs producing Escherichia coli.}, journal = {Bioorganic chemistry}, volume = {140}, number = {}, pages = {106780}, doi = {10.1016/j.bioorg.2023.106780}, pmid = {37579620}, issn = {1090-2120}, abstract = {Seven rarely spirooxindole alkaloids, voagafricines A-G (1-7) were isolated from the stem barks of Voacanga africana. Their structures were unambiguously elucidated by comprehensive spectroscopic data and electronic circular dichroism (ECD) analyses. 1 and 2 possess a unique indoleone system in conjugation with a 3,4'-decahydroquinoline spiral ring originating from seco-quinolhiddin core of the precursor, furthermore 1 undergo decarburization formed a novel C-3-nor monoterpenoid indole. All isolates were evaluated for their antibacterial activities against MBLs producing Escherichia coli strains. Compounds 1 and 7 were found to be potent inhibitors against E. coli 298 and 140 by targeting biofilm. Possible interaction sites of 1 and 7 with biofilm were preliminarily explored by means of molecular docking.}, } @article {pmid37576771, year = {2023}, author = {Lenchenko, E and Sachivkina, N and Lobaeva, T and Zhabo, N and Avdonina, M}, title = {Bird immunobiological parameters in the dissemination of the biofilm-forming bacteria Escherichia coli.}, journal = {Veterinary world}, volume = {16}, number = {5}, pages = {1052-1060}, pmid = {37576771}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: With the development of industrial maintenance technology, a group of pathogens called avian pathogenic Escherichia coli (APEC) became very common. The initiation, development, and outcome of the infectious process mediated by virulent APEC strains occur through a decrease in the colonization resistance of the intestine, an immunobiological marker of homeostasis stability in susceptible species. This study focused on the pathogenetic features of colibacillosis and the morphological features of E. coli.

MATERIALS AND METHODS: Clinical, immunological, bacteriological, and histological studies were conducted on 15-day-old white Leghorn birds (n = 20). The birds were divided into two groups: Control group (Group I; n = 10) with birds intranasally inoculated with 0.5 mL of 0.9% NaCl solution and experimental group (Group II; n = 10) with birds intranasally inoculated with 0.5 mL of an E. coli suspension at 1 billion/mL.

RESULTS: During the biofilm formation, clusters of microcolonies were formed as a gel-like intercellular matrix that accumulated due to cell coagulation. The intercellular matrix "glues" heteromorphic cells together and forms a structure of densely packed heteromorphic cells arranged in an orderly manner and growing in different directions. During the experimental reproduction of E. coli, excessive growth was observed in material isolated from poultry. Pathogenic E. coli strains implementing virulence factors adhered to the receptors of erythrocytes, alveolocytes, and enterocytes. Multicellular heterogeneous biofilms, united by an intercellular matrix, were located at the apical poles of the respiratory tract alveolocytes and enterocytes of the terminal ileum villi. Many bacteria exudate containing desquamated epithelial cells with an admixture of mucus, and polymorphonuclear leukocytes were detected in the lumen of the birds' abdominal organs. Invasive bacteria damaged the epithelial layer, violated the endothelial layer of blood vessels, and developed inflammatory hyperemia of the lamina propria of the respiratory and digestive systems' mucous membrane. A correlative dependence of changes developed by the type of delayed hypersensitivity reaction was established. Signs of accidental transformation of the thymus, atrophy of the bursa of Fabricius, disseminated thrombosis, and septic spleen developed. Moreover, toxic cardiomyocyte dystrophy, signs of congestive vascular hyperemia, massive disintegration of lymphocytes, macrophage reactions, perivascular edema resulting from the release of plasma, and shaped blood elements were detected.

CONCLUSION: The development and outcome of the infectious process in escherichiosis primarily depend on the homeostasis stability of susceptible species and virulence factors of the pathogenic microorganisms. One of the selected strains, E. coli O78:K80 displayed the highest ability to form biofilms. Its strong adhesion ability to bird erythrocytes was demonstrated. Deepening the scientific knowledge of the interaction between eukaryotes and prokaryotes will contribute to a better understanding of the pathogenetic aspects of avian escherichiosis and eventually find promising anti-adhesive drugs that could reduce primary bacterial contamination in vivo and in vitro.}, } @article {pmid37575388, year = {2023}, author = {Sterniša, M and Sabotič, J and Janež, N and Curk, T and Klančnik, A}, title = {SIMBA Method-Simultaneous Detection of Antimicrobial and Anti-biofilm Activity of New Compounds Using Salmonella Infantis.}, journal = {Bio-protocol}, volume = {13}, number = {15}, pages = {e4783}, pmid = {37575388}, issn = {2331-8325}, abstract = {The development of antimicrobial resistance and the formation of Salmonella biofilms are serious public health problems. For this reason, new natural compounds with antimicrobial and anti-biofilm activity are being sought, and wild fungi represent an untapped potential. Various extraction agents, including organic solvents and aqueous buffers, can be used to obtain bioactive compounds from natural sources. To evaluate their bioactivity, extensive screening studies are required to determine antimicrobial and anti-biofilm activity using methods such as broth microdilution or crystal violet assay, respectively, but none of these methods allow simultaneous evaluation of both activities against bacteria. Cold water extraction from wild fungi offers the advantage of extracting water-soluble compounds. The SIMultaneous detection of antiMicrobial and anti-Biofilm Activity (SIMBA) method combines the testing of both types of activity against bacteria with the evaluation of the 20 h growth curve of the Salmonella Infantis ŽM9 strain determined with absorbance measurements at 600 nm in a 96-well plate. SIMBA method thus shortens the time to determine the bioactivity of extracts, reduces material consumption, and eliminates the need for additional reagents. SIMBA enables rapid selection of bioactive extracts for their fractionation and shortens the time to determine new natural products with antimicrobial and anti-biofilm activity. Graphical overview.}, } @article {pmid37574084, year = {2023}, author = {Riechelmann, C and Habashy, MM and Rene, ER and Moussa, MS and Hosney, H}, title = {Assessment of hybrid fixed and moving bed biofilm applications for wastewater treatment capacity increase - In situ tests in El-Gouna WWTP, Egypt.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139783}, doi = {10.1016/j.chemosphere.2023.139783}, pmid = {37574084}, issn = {1879-1298}, abstract = {This paper provides a procedure for comparing the performance of different biofilm carrier medias and their surrounding suspended biomass through oxygen uptake rate (OUR) tests. For in situ OUR measurements three identical lab scale biofilm reactors were set up at the El Gouna wastewater treatment plant (WWTP). In this setup two options of media for moving-bed biofilm reactors (MBBR) and one media for fixed-bed biofilm reactors (FBBR) were compared. The WWTP also used the same carrier in a real scale hybrid application to analyze how the interactions between the carrier type and the suspended biomass influences the overall performance. The in situ OUR approach is recommended to measure the contribution of the biofilm fixed biomass under side specific conditions. Especially settleability and diffusion limitations are here the two opposite poles that for warm climate conditions can't be sufficiently predicted based on literature. A biofilm carrier application can add but actually can also reduce the capacity in a hybrid activated sludge system: Added MBBR-media are able to grind down sludge flocs forming a badly settleable suspended biomass. Added FBBR-media can lead to EPS rich biofilms that contribute very little as substrate and oxygen are unavailable for the biofilm organisms. In this application of the comparison procedure, Kaldnes K1 like MBBR media was compared with a recycling MBBR carrier option (poly propylene bottle caps) and Jäger Envirotech "BioCurlz™" FBBR media. The study showed higher average rates for the MBBR but decreased settleability. The FBBR showed higher peak rates when flushed to break up the biofilm and well settleable sludge. The determination of OUR per gram of volatile solids (SOUR) showed equal results for all carriers and that in warm conditions only the capacity to accommodate biomass, determines the contribution of the carrier.}, } @article {pmid37571905, year = {2023}, author = {Farhan, RE and Solyman, SM and Hanora, AM and Azab, MM}, title = {Molecular detection of different virulence factors genes harbor pslA, pelA, exoS, toxA and algD among biofilm-forming clinical isolates of Pseudomonas aeruginosa.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {5}, pages = {32-39}, doi = {10.14715/cmb/2023.69.5.6}, pmid = {37571905}, issn = {1165-158X}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is considered as the foremost cause of hospital-acquired infections due to its innate and plasmid-mediated resistance to multiple antibiotics making it a multi-drug resistant (MDR) pathogen. This study aimed to determine the biofilm formation ability and the presence of different virulence factors genes (pslA, pelA, exoS, toxA and algD) among biofilm-forming strains of P. aeruginosa clinical isolates from burn units in Ismailia Hospitals, Egypt. In our cross-sectional study, one hundred and twenty-six (126) non-duplicate clinical P. aeruginosa isolates were recovered from 450 clinical specimens from burn units in Ismailia Hospitals. The antibiotic sensitivity of strong and moderate biofilm producer isolates was investigated using the disc diffusion method. The isolated bacteria were tested for their ability to form biofilm using a microtiter plate assay. The expression of (pslA, pelA, exoS, toxA and algD) genes in biofilm producers isolates was detected using PCR. The MPA detected 80% (95 /126) isolates as biofilm producers, 18% (22/126) were strong biofilm producers, 34% (43/126) were moderate biofilm producers, 28% (35/126) were weak biofilm producers and 20% (31/126) non-biofilm producers. Susceptibility pattern analysis of biofilm-forming P. aeruginosa isolates (95) detected that 60% (68/ 95) were multi-drug resistant isolates (MDR). Resistance to all used antibiotics and multidrug resistance was higher among biofilm-producing than non-biofilm-producing strains, but the difference was statistically non-significant. Investigation of virulence factors associated genes revealed that 96%, 94%, 86.4%, 80.0% and 74% of the biofilm producers isolates were harboring algD, pslA, pel A, toxA and exoS gene, respectively. The present study confirmed that antimicrobial resistance and virulence genes were more prominent in biofilm-producing P. aeruginosa than in non-biofilm-producers.}, } @article {pmid37571901, year = {2023}, author = {Fang, X and Zhu, L and Wu, Q and Zhong, X and Chen, Y and Zhu, W}, title = {The Influence of MDR1 Expression Regulated by miR-138 through TRPS1 Signaling Pathway on Multidrug Resistance of Osteosarcoma and Formation of Bacterial Infection Biofilm.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {5}, pages = {51-57}, doi = {10.14715/cmb/2023.69.5.9}, pmid = {37571901}, issn = {1165-158X}, abstract = {This study was to investigate the effect of microribonucleic acid (mi-RNA) on the resistance of human multidrug resistance gene 1 (MDR1) to osteosarcoma through the Trico-nasal finger syndrome 1 (TRPS1) pathway, as well as the effect of mi-RNA on biofilm formation. For this purpose, firstly, the expression of MDR1 and TRPS1 in osteosarcoma cells was detected by quantitative polymerase chain reaction (qPCR) technology. Moreover, the clinical paraffin sections of osteosarcoma cells were collected to explore the correlation between MDR1 and TRPS1. Then, both the MG-38 cells expressing and not expressing miR-138 were expanded. Afterward, a plasmid with a full-length clone of the TRPS1 antibody was applied to transfect the cells. Besides, Q-OCR was employed to detect the expression of TRPS1 and MDR1, and the expression of TRPS1 protein and P-glycoprotein (P-gp) was detected by Western blot (WB). The MTT method was adopted to detect the changes in the median lethal dose of doxorubicin and cisplatin in cells from each group. The well plate was used to establish an in vitro bacterial infection biofilm model, and the above two transfected cells were added during the model establishment process. Moreover, the formation of biofilm in the two groups was observed. The result of the paraffin biopsy was 33% (25/75) of mi-RNA, the positive rate of TRPS1 was 18.6%, and the Pearson correlation coefficient of the two was 0.477. Under mi-RNA interference, the TRPS1 and MDR1 of the three system cells were sharply reduced, and the trend of changes between the two was the same. The tolerance of the mi-RNA interference group to doxorubicin, cisplatin, paclitaxel and 5-fluorouracil decreased steeply, and the median lethal dose dropped, while the non-mi-RNA interference group showed the opposite trend. In addition, the number of colonies in the interference group was less sharp than that of the control group and the non-mi-RNA interference group. The conclusion was that mi-RNA could control the expression of MDR1 through the TRPS1 pathway, thus affecting the multi-drug resistance of osteosarcoma and also influencing the formation of bacterial biofilms.}, } @article {pmid37571254, year = {2023}, author = {Guo, M and Wu, J and Hung, W and Sun, Z and Zhao, W and Lan, H and Zhao, Z and Wuri, G and Fang, B and Zhao, L and Zhang, M}, title = {Lactobacillus paracasei ET-22 Suppresses Dental Caries by Regulating Microbiota of Dental Plaques and Inhibiting Biofilm Formation.}, journal = {Nutrients}, volume = {15}, number = {15}, pages = {}, doi = {10.3390/nu15153316}, pmid = {37571254}, issn = {2072-6643}, support = {23JF0006//R&D Program of Beijing Municipal Education Commission/ ; 31601443//National Natural Science Foundation of China/ ; 32101938//National Natural Science Foundation of China/ ; 2022M723422//China Postdoctoral Science Foundation/ ; }, abstract = {Dental caries is a common and multifactorial biofilm disease that is associated with dietary habits and microbiota. Among the various pathogens inducing caries, S. mutans is the most extensively studied. Promoting oral health with probiotics has gained considerable attention. Lactobacillus paracasei (L. paracasei) strains were reported to modulate the gut microbiota and enhance host resistance to disease. Our previous research has found that L. paracasei ET-22 (ET-22) could inhibit S. mutans biofilms in vitro. However, the preventive effect in vivo and functional mechanism of ET-22 on dental caries were unclear. In this study, the preventive effects of ET-22 on dental caries in mice were checked. Meanwhile, the functional mechanism of ET-22 was further investigated. Results showed that the supplementation of ET-22 in drinking water significantly improved the caries scoring of mice. The microbiota of dental plaques revealed that the live and heat-killed ET-22 similarly regulated the microbial structure in plaque biofilms. Functional prediction of PICRUSt showed that the addition of live and heat-killed ET-22 may inhibit biofilm formation. By the in vitro trials, the live and heat-killed ET-22 indeed inhibited the construction of S. mutans biofilms and EPS productions of biofilms. This evidence suggests that ET-22 can restrain dental caries by regulating the microbiota of dental plaques and inhibiting biofilm formation, which may be partly mediated by the body components of ET-22.}, } @article {pmid37569471, year = {2023}, author = {Mahmoud, M and Richter, P and Lebert, M and Burkovski, A}, title = {Photodynamic Activity of Chlorophyllin and Polyethylenimine on Pseudomonas aeruginosa Planktonic, Biofilm and Persister Cells.}, journal = {International journal of molecular sciences}, volume = {24}, number = {15}, pages = {}, doi = {10.3390/ijms241512098}, pmid = {37569471}, issn = {1422-0067}, support = {50WB1923//German Aerospace Center/ ; 2019 (57460069)//German Academic Exchange Service/ ; }, abstract = {Antimicrobial photodynamic inactivation is considered a promising antimicrobial approach that may not develop resistance in the near future. Here, we investigate the influence of the photosensitizer chlorophyllin (CHL) and the cationic permeabilizer polyethylenimine (PEI), exposed to a red light-emitting diode, on the human pathogen Pseudomonas aeruginosa free-living planktonic cells, the sessile biofilm and persister cells. The broth microdilution checkerboard method was used to test antimicrobial susceptibility. As a substrate for biofilms, the Calgary biofilm device was used, and the quantification of the biofilm biomass was carried out using a crystal violet assay. Serine hydroxamate was used for the induction of persisters. Our findings reveal that PEI ameliorates the antimicrobial activity of CHL against P. aeruginosa planktonic and biofilm states, and the concentration required to eradicate the bacteria in the biofilm is more than fourfold that is required to eradicate planktonic cells. Interestingly, the persister cells are more susceptible to CHL/PEI (31.25/100 µg mL[-1]) than the growing cells by 1.7 ± 0.12 and 0.4 ± 0.1 log10 reduction, respectively, after 15 min of illumination. These data demonstrate that CHL excited with red light together with PEI is promising for the eradication of P. aeruginosa, and the susceptibility of P. aeruginosa to CHL/PEI is influenced by the concentrations and the exposure time.}, } @article {pmid37569105, year = {2023}, author = {Lianou, DT and Michael, CK and Solomakos, N and Vasileiou, NGC and Petinaki, E and Mavrogianni, VS and Tzora, A and Voidarou, C and Fthenakis, GC}, title = {Isolation of Biofilm-Forming Staphylococci from the Bulk-Tank Milk of Small Ruminant Farms in Greece.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {15}, pages = {}, doi = {10.3390/foods12152836}, pmid = {37569105}, issn = {2304-8158}, abstract = {The objectives of this study were (i) to describe staphylococcal isolates recovered from bulk-tank raw milk collected from sheep and goat farms during a countrywide study performed in Greece, (ii) to study management factors potentially associated with their presence in bulk-tank milk and (iii) to provide evidence regarding their association with the quality of the milk. In total, 312 staphylococcal isolates, recovered from samples of bulk-tank raw milk from 444 small ruminant farms in Greece, were evaluated in this work. The in vitro formation of biofilm by the isolates was tested by combining the findings of (a) culture appearance on Congo Red agar plates and (b) results of a microplate adhesion test. The most frequently identified species was Staphylococcus aureus (75 isolates); other frequently recovered species were S. simulans (44 isolates), S. equorum (34 isolates) and S. haemolyticus (26 isolates); in total, 23 species were identified. In total, 224 (71.8%) isolates were biofilm-forming and were recovered from the bulk-tank milk samples of 148 sheep flocks (45.5%) and 55 goat herds (46.2%). There was evidence of seasonality in the isolation of staphylococci: during spring, mostly biofilm-forming isolates were recovered, whilst during summer, mostly non-biofilm-forming isolates were recovered. Among farms applying machine-milking, the proportion of farms from which biofilm-forming isolates were recovered was higher where water with temperature < 50 °C or ≥90 °C was used to clean the milking parlour. In the multivariable analyses, for farms applying machine-milking, the temperature of the water emerged as the only significant variable (p = 0.024), whilst in farms applying hand-milking, the only tendency that emerged was for the frequency of collection of milk from the farm tank (p = 0.08). In sheep flocks, recovery of biofilm-forming staphylococci from the bulk-tank milk was associated with higher somatic cell counts and higher total bacterial counts in the milk. The study identified abiotic factors related to the presence and isolation of these bacteria, specifically the temperature of water used for the cleaning of the milking parlour (in farms where machine-milking is applied) and the frequency of milk collection from the farm tank. These factors apply after the production of milk, and they could thus be regulated appropriately in order to reduce bacterial load and improve the quality of milk delivered to dairy plants. In sheep farms, an association was also seen between recovery of biofilm-forming staphylococci and high somatic cell counts in milk.}, } @article {pmid37567926, year = {2023}, author = {Ribeiro, JM and Pereira, GN and Durli Junior, I and Teixeira, GM and Bertozzi, MM and Verri, WA and Kobayashi, RKT and Nakazato, G}, title = {Comparative analysis of effectiveness for phage cocktail development against multiple Salmonella serovars and its biofilm control activity.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {13054}, pmid = {37567926}, issn = {2045-2322}, abstract = {Foodborne diseases are a major challenge in the global food industry, especially those caused by multidrug-resistant (MDR) bacteria. Bacteria capable of biofilm formation, in addition to MDR strains, reduce the treatment efficacy, posing a significant threat to bacterial control. Bacteriophages, which are viruses that infect and kill bacteria, are considered a promising alternative in combating MDR bacteria, both in human medicine and animal production. Phage cocktails, comprising multiple phages, are commonly employed to broaden the host range and prevent or delay the development of phage resistance. There are numerous techniques and protocols available to evaluate the lytic activity of bacteriophages, with the most commonly used methods being Spot Test Assays, Efficiency of Plating (EOP), and infection assays in liquid culture. However, there is currently no standardization for which analyses should be employed and the possible differences among them in order to precisely determine the host range of phages and the composition of a cocktail. A preliminary selection using the Spot Test Assay resulted in four phages for subsequent evaluation against a panel of 36 Salmonella isolates of numerous serovars. Comparing EOP and infection assays in liquid culture revealed that EOP could underestimate the lytic activity of phages, directly influencing phage cocktail development. Moreover, the phage cocktail containing the four selected phages was able to control or remove biofilms formed by 66% (23/35) of the isolates, including those exhibiting low susceptibility to phages, according to EOP. Phages were characterized genomically, revealing the absence of genes associated with antibiotic resistance, virulence factors, or integrases. According to confocal laser scanning microscopy analysis, the biofilm maturation of one Salmonella isolate, which exhibited high susceptibility to phages in liquid culture and 96-well plates biofilm viability assays but had low values for EOP, was found to be inhibited and controlled by the phage cocktail. These observations indicate that phages could control and remove Salmonella biofilms throughout their growth and maturation process, despite their low EOP values. Moreover, using infection assays in liquid culture enables a more precise study of phage interactions for cocktail design timelessly and effortlessly. Hence, integrating strategies and techniques to comprehensively assess the host range and lytic activity of bacteriophages under different conditions can demonstrate more accurately the antibacterial potential of phage cocktails.}, } @article {pmid37567643, year = {2023}, author = {Gunther, NW and Nunez, A and Bagi, L and Abdul-Wakeel, A and Ream, A and Liu, Y and Uhlich, G}, title = {Butyrate decreases Campylobacter jejuni motility and biofilm partially through influence on LysR expression.}, journal = {Food microbiology}, volume = {115}, number = {}, pages = {104310}, doi = {10.1016/j.fm.2023.104310}, pmid = {37567643}, issn = {1095-9998}, abstract = {The food pathogen Campylobacter jejuni both colonizes the lower intestines of poultry and infects the lower intestines of humans. The lower intestines of both poultry and humans are also home to a wide range of commensal organisms which compete with an organism like C. jejuni for space and resources. The commensal organisms are believed to protect humans against infection by pathogens of the digestive tract like C. jejuni. The short chain fatty acid (SCFA) butyrate is a metabolite commonly produced by commensal organisms within both the poultry and human digestive tract. We investigated the effect that physiologically relevant concentrations of butyrate have on C. jejuni under in vitro conditions. Butyrate at concentrations of 5 and 20 mM negatively impacted C. jejuni motility and biofilm formation. These two traits are believed important for C. jejuni's ability to infect the lower intestines of humans. Additionally, 20 mM butyrate concentrations were observed to influence the expression of a range of different Campylobacter proteins. Constitutive expression of one of these proteins, LysR, within a C. jejuni strain partially lessened the negative influence butyrate had on the bacteria's motility.}, } @article {pmid37567468, year = {2023}, author = {Dallal, MMS and Kelishomi, FZ and Nikkhahi, F and Salehi, TZ and Fardsanei, F and Peymani, A}, title = {Biofilm Formation, antimicrobial resistance genes and genetic diversity of Salmonella enterica subspecies enterica serotype Enteritidis isolated from food and animal sources in Iran.}, journal = {Journal of global antimicrobial resistance}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jgar.2023.08.004}, pmid = {37567468}, issn = {2213-7173}, abstract = {OBJECTIVE: Salmonella enterica serovar Entritidis is an important pathogen in foodborne diseases and causes gastroenteritis. Several studies have investigated the genetic diversity of the strains of this bacterium. However, our knowledge of the discriminatory power of the molecular methods is limited.

METHODS: 34 strains of S. enteritidis were isolated from food related to animals. Antibiotic resistance of the strains, antibiotic resistance genes, and biofilm formation capacity of the strains were evaluated. For the genetic analysis of the strains, PFGE was performed using AvrII restriction enzyme.

RESULTS: Among the tested antibiotics, cefuroxime, nalidixic acid, and ciprofloxacin showed the highest resistance rates (79.4%, 47%, and 44.2%, respectively). Only three antibiotic-resistance genes were identified in these strains (blaTEM: 67.6%, tetA: 9%, and sul2: 3%). In total, 91% of the strains were biofilm-producers. Clustering of strains using AvrII for 26 samples with the same XbaI PFGE profile, showed that these strains were in one clone and had high homogeneity.

CONCLUSIONS: In conclusion, it is better to use a combination of several typing methods for typing strains that are genetically very close so that the results are reliable.}, } @article {pmid37566788, year = {2023}, author = {Yin, Z and Liu, Y and Anniwaer, A and You, Y and Guo, J and Tang, Y and Fu, L and Yi, L and Huang, C}, title = {Rational Designs of Biomaterials for Combating Oral Biofilm Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2305633}, doi = {10.1002/adma.202305633}, pmid = {37566788}, issn = {1521-4095}, abstract = {Oral biofilms, which are also known as dental plaque, are the culprit of a wide range of oral diseases and systemic diseases, thus contributing to serious health risks. The manner of how to achieve good control of oral biofilms has been an increasing public concern. Novel antimicrobial biomaterials with highly controllable fabrication and functionalization have been proven to be promising candidates. However, previous reviews have generally emphasized the physicochemical properties, action mode, and application effectiveness of those biomaterials, whereas insufficient attention has been given to the design rationales tailored to different infection types and application scenarios. To offer guidance for better diversification and functionalization of anti-oral-biofilm biomaterials, this review details the up-to-date design rationales in three aspects: the core strategies in combating oral biofilm, as well as the biomaterials with advanced antibiofilm capacity and multiple functions based on the improvement or combination of the abovementioned antimicrobial strategies. Thereafter, insights on the existing challenges and future improvement of biomaterial-assisted oral biofilm treatments are proposed, hoping to provide a theoretical basis and reference for the subsequent design and application of antibiofilm biomaterials. This article is protected by copyright. All rights reserved.}, } @article {pmid37566512, year = {2023}, author = {Grayton, QE and Nguyen, HK and Broberg, CA and Ocampo, J and Nagy, SG and Schoenfisch, MH}, title = {Biofilm Dispersal, Reduced Viscoelasticity, and Antibiotic Sensitization via Nitric Oxide-Releasing Biopolymers.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00198}, pmid = {37566512}, issn = {2373-8227}, abstract = {Compared to planktonic bacteria, biofilms are notoriously difficult to eradicate due to their inherent protection against the immune response and antimicrobial agents. Inducing biofilm dispersal to improve susceptibility to antibiotics is an attractive therapeutic avenue for eradicating biofilms. Nitric oxide (NO), an endogenous antibacterial agent, has previously been shown to induce biofilm dispersal, but with limited understanding of the effects of NO-release properties. Herein, the antibiofilm effects of five promising NO-releasing biopolymer candidates were studied by assessing dispersal, changes in biofilm viscoelasticity, and increased sensitization to tobramycin after treatment with NO. A threshold level of NO was needed to achieve biofilm dispersal, with longer-releasing systems requiring lower concentrations. The most positively charged NO-release systems (from the presence of primary amines) led to the greatest reduction in viscoelasticity of Pseudomonas aeruginosa biofilms. Co-treatment of tobramycin with the NO-releasing biopolymer greatly decreased the dose of tobramycin required to eradicate tobramycin-susceptible and -resistant biofilms in both cellular and tissue models.}, } @article {pmid37566205, year = {2023}, author = {Moogahi, S and Beni, FT and Hashemzadeh, M and Dezfuli, AAZ}, title = {Molecular identification and biofilm formation of aerobic and anaerobic coinfection bacterial isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022.}, journal = {Molecular biology reports}, volume = {}, number = {}, pages = {}, pmid = {37566205}, issn = {1573-4978}, abstract = {BACKGROUND: Coinfections and resistant bacterial infections are more likely to occur in cystic fibrosis patients because their immune systems are weak. The purpose of this study was to identify by molecular means as well as the formation of biofilm of aerobic and anaerobic coinfection bacteria isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022.

METHODS: In this investigation, 130 clinical specimens were collected from 130 CF patients by universal primer. Biofilm formation was investigated using the microtiter plate method. Antibiotic resistance was measured using Vitec 2 device. In addition, identification of methicillin-resistant Staphylococcus aureus using genes mecA was performed.

MAIN FINDINGS: In aerobic bacteria, Pseudomonas aeruginosa was detected in (32%) of samples. In anaerobic bacteria (16%) Prevotella spp. was the most frequently isolated anaerobe bacteria found in of the CF patients. In this study, 75% of the bacteria could form biofilms, while 23% were unable to biofilm formation.

CONCLUSION: In conclusion, P. aeruginosa was found to be the most frequently isolated bacterium from patients with CF, and many of these bacteria could form biofilms. Additionally, the high prevalence of antibiotic resistance indicates the urgent need for increased attention to antibiotic preparation and patient screening concerning bacterial coinfections and the virulence and adhesion factors of these bacteria. Furthermore, the present study demonstrates that the coinfection of bacteria with high antibiotic resistance and a high capacity for biofilm formation can pose a life-threatening risk to CF patients, mainly due to their weakened immune systems.}, } @article {pmid37564292, year = {2023}, author = {Kurbatfinski, N and Kramer, CN and Goodman, SD and Bakaletz, LO}, title = {ESKAPEE pathogens newly released from biofilm residence by a targeted monoclonal are sensitized to killing by traditional antibiotics.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1202215}, pmid = {37564292}, issn = {1664-302X}, abstract = {INTRODUCTION: The "silent" antimicrobial resistance (AMR) pandemic is responsible for nearly five million deaths annually, with a group of seven biofilm-forming pathogens, known as the ESKAPEE pathogens, responsible for 70% of these fatalities. Biofilm-resident bacteria, as they exist within the disease site, are canonically highly resistant to antibiotics. One strategy to counter AMR and improve disease resolution involves developing methods to disrupt biofilms. These methods aim to release bacteria from the protective biofilm matrix to facilitate their killing by antibiotics or immune effectors. Several laboratories working on such strategies have demonstrated that bacteria newly released from a biofilm display a transient phenotype of significantly increased susceptibility to antibiotics. Similarly, we developed an antibody-based approach for biofilm disruption directed against the two-membered DNABII family of bacterial DNA-binding proteins, which serve as linchpins to stabilize the biofilm matrix. The incubation of biofilms with α-DNABII antibodies rapidly collapses them to induce a population of newly released bacteria (NRel).

METHODS: In this study, we used a humanized monoclonal antibody (HuTipMab) directed against protective epitopes of a DNABII protein to determine if we could disrupt biofilms formed by the high-priority ESKAPEE pathogens as visualized by confocal laser scanning microscopy (CLSM) and COMSTAT2 analysis. Then, we demonstrated the potentiated killing of the induced NRel by seven diverse classes of traditional antibiotics by comparative plate count.

RESULTS: To this end, ESKAPEE biofilms were disrupted by 50%-79% using a single tested dose and treatment period with HuTipMab. The NRel of each biofilm were significantly more sensitive to killing than their planktonically grown counterparts (heretofore, considered to be the most sensitive to antibiotic-mediated killing), even when tested at a fraction of the MIC (1/250-1/2 MIC). Moreover, the bacteria that remained within the biofilms of two representative ESKAPEE pathogens after HuTipMab disruption were also significantly more susceptible to killing by antibiotics.

DISCUSSION: New data presented in this study support our continued development of a combinatorial therapy wherein HuTipMab is delivered to a patient with recalcitrant disease due to an ESKAPEE pathogen to disrupt a pathogenic biofilm, along with a co-delivered dose of an antibiotic whose ability to rapidly kill the induced NRel has been demonstrated. This novel regimen could provide a more successful clinical outcome to those with chronic, recurrent, or recalcitrant diseases, while limiting further contribution to AMR.}, } @article {pmid37564117, year = {2023}, author = {Prince, J and Jones, AD}, title = {Heterogenous Biofilm Mass-Transport Model Replicates Periphery Sequestration of Antibiotics in P. aeruginosa PAO1 Microcolonies.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {37564117}, abstract = {A spatiotemporal model for antibiotic accumulation in bacterial biofilm microcolonies which leverages heterogenous porosity and attachment site profiles replicated the periphery sequestration phenomena reported in prior experimental studies on Pseudomonas aeruginosa PAO1 biofilm cell clusters. These P. aeruginosa cell clusters are in vitro models of the chronic P. aeruginosa infections found in adult cystic fibrosis patients, which display resistance to antibiotic treatments, leading to exacerbated morbidity and mortality. This resistance has been partially attributed to periphery sequestration, where antibiotics are unable to penetrate biofilm cell clusters. The underlying physical phenomena driving this periphery sequestration have not been definitively established. This paper introduces mathematical models to account for two proposed physical phenomena driving periphery sequestration: biofilm matrix attachment and volume-exclusion due to variable biofilm porosity. An antibiotic accumulation model which incorporated these phenomena was able to better fit observed periphery sequestration data compared to previous models.}, } @article {pmid37563215, year = {2023}, author = {Wilbanks, KQ and Mokrzan, EM and Kesler, TM and Kurbatfinski, N and Goodman, SD and Bakaletz, LO}, title = {Nontypeable Haemophilus influenzae released from biofilm residence by monoclonal antibody directed against a biofilm matrix component display a vulnerable phenotype.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {12959}, pmid = {37563215}, issn = {2045-2322}, support = {R01DC003915//U.S. Department of Health & Human Services | NIH | National Institute on Deafness and Other Communication Disorders (NIDCD)/ ; R01DC011818//U.S. Department of Health & Human Services | NIH | National Institute on Deafness and Other Communication Disorders (NIDCD)/ ; }, abstract = {Bacterial biofilms contribute significantly to pathogenesis, recurrence and/or chronicity of the majority of bacterial diseases due to their notable recalcitrance to clearance. Herein, we examined kinetics of the enhanced sensitivity of nontypeable Haemophilus influenzae (NTHI) newly released (NRel) from biofilm residence by a monoclonal antibody against a bacterial DNABII protein (α-DNABII) to preferential killing by a β-lactam antibiotic. This phenotype was detected within 5 min and lasted for ~ 6 h. Relative expression of genes selected due to their known involvement in sensitivity to a β-lactam showed transient up-regulated expression of penicillin binding proteins by α-DNABII NTHI NRel, whereas there was limited expression of the β-lactamase precursor. Transient down-regulated expression of mediators of oxidative stress supported similarly timed vulnerability to NADPH-oxidase sensitive intracellular killing by activated human PMNs. Further, transient up-regulated expression of the major NTHI porin aligned well with observed increased membrane permeability of α-DNABII NTHI NRel, a characteristic also shown by NRel of three additional pathogens. These data provide mechanistic insights as to the transient, yet highly vulnerable, α-DNABII NRel phenotype. This heightened understanding supports continued validation of this novel therapeutic approach designed to leverage knowledge of the α-DNABII NRel phenotype for more effective eradication of recalcitrant biofilm-related diseases.}, } @article {pmid37563082, year = {2023}, author = {Amaral, SC and Pruski, BB and de Freitas, SB and Dos Santos, LM and Hartwig, DD}, title = {Biofilm formation in drug-resistant Acinetobacter baumannii and Acinetobacter nosocomialis isolates obtained from a university hospital in Pelotas, RS, Brazil.}, journal = {Letters in applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/lambio/ovad094}, pmid = {37563082}, issn = {1472-765X}, abstract = {This study aimed to investigate the antibiotic resistance and biofilm formation of Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex isolates recovered from a university hospital in Pelotas, RS, Brazil. The species were confirmed using gyrB multiplex and blaOXA-51-like genes PCR. The presence of the bfmRS virulence gene was evaluated by the PCR, and the isolates were classified based on their biofilm-forming ability on polystyrene (PO) and glass surfaces (TM). Out of 50 ACB complex isolates evaluated, 41 were identified as A. baumannii and 9 as A. nosocomialis. The bfmRS gene was detected in 97.6% (40/41) of A. baumannii and 33.3% (3/9) of A. nosocomialis species. Forty-nine isolates exhibited a multi-drug resistant (MDR) profile, while one A. nosocomialis isolate presented an extended-drug resistant (XDR) profile. All isolates were able of forming biofilms on PO surfaces, and 98% (49/50) on TM surfaces. A significant correlation was observed between biofilm production on PO and TM surfaces (p < 0.05). However, no correlation was found between biofilms forming and the presence of bfmRS gene or displaying a certain antibiotic resistance profile. In conclusion, A. baumannii and A. nosocomialis are frequent species causing nosocomial infections in a hospital in Pelotas, RS, Brazil, and both are capable of forming biofilms.}, } @article {pmid37560518, year = {2023}, author = {Song, W and Ryu, J and Jung, J and Yu, Y and Choi, S and Kweon, J}, title = {Dispersive biofilm from membrane bioreactor strains: effects of diffusible signal factor addition and characterization by dispersion index.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1211761}, pmid = {37560518}, issn = {1664-302X}, abstract = {INTRODUCTION: Biofilm occurs ubiquitously in water system. Excessive biofilm formation deteriorates severely system performance in several water and wastewater treatment processes. Quorum sensing systems were controlled in this study with a signal compound cis-2-Decenoic acid (CDA) to regulate various functions of microbial communities, including motility, enzyme production, and extracellular polymeric substance (EPS) production in biofilm.

METHODS: The addition of CDA to six strains extracted from membrane bioreactor sludge and the Pseudomonas aeruginosa PAO1 strain was examined for modulating biofilm development by regulating DSF expression.

RESULTS AND DISCUSSION: As the CDA doses increased, optical density of the biofilm dispersion assay increased, and the decrease in EPS of the biofilm was obvious on membrane surfaces. The three-dimensional visual images and quantitative analyses of biofilm formation with CDA proved thinner, less massive, and more dispersive than those without; to evaluate its dispersive intensity, a dispersion index was proposed. This could compare the dispersive effects of CDA dosing to other biofilms or efficiencies of biofouling control practices such as backwashing or new cleaning methods.}, } @article {pmid37558015, year = {2023}, author = {Srinivash, M and Krishnamoorthi, R and Mahalingam, PU and Malaikozhudan, B}, title = {Exopolysaccharide from Lactococcus hircilactis CH4 and Lactobacillus delbrueckii GRIPUMSK as new therapeutics to treat biofilm pathogens, oxidative stress and human colon adenocarcinoma.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {126171}, doi = {10.1016/j.ijbiomac.2023.126171}, pmid = {37558015}, issn = {1879-0003}, abstract = {Naturally occurring biopolymers like exopolysaccharides (EPS) secreted by lactic acid bacteria (LAB) has gained significant attention as they are cost effective, renewable and safe. In order to prevent the rapid increase in antibiotic resistant bacteria, the EPS of LAB offers novel approach of targeting the antibiotic resistant pathogens by limiting their effects on environment. Accordingly, in this study, the production, purification, characterization and biological properties of exopolysaccharides from Lactococcus hircilactis strain CH4 and Lactobacillus delbrueckii strain GRIPUMSK were performed. The optimization of lactic acid bacterial strains for exopolysaccharide production was done by response surface methodology and changing the carbon sources in the growth media. The carbohydrate and protein of exopolysaccharide 1 were 79.7 % and 8.7 % respectively and exopolysaccharide 2 were 75.2 % and 9.3 % respectively. When compared with the commercial emulsifier sodium dodecyl sulfate, both the exopolysaccharides have shown good emulsifying activity. Both the exopolysaccharides were linear homo-polysaccharide as determined by Fourier transform infrared spectroscopy and Nuclear magnetic resonance spectra. Scanning electron microscopy showed that the exopolysaccharides were porous and capable of holding water. The exopolysaccharides were partially crystalline as confirmed by X-ray diffraction spectra. Exopolysaccharides from L. hircilactis and L. delbrueckii exhibited significant antimicrobial activity against H. pylori, S. flexneri, S. pyogenes, E. faecalis and C. albicans. Both the exopolysaccharides revealed significant 2,2-diphenyl-1-picrylhydrazyl and hydrogen peroxide scavenging ability with the IC50 value of 100 μg/ml and 80 μg/ml respectively. Exopolysaccharides from L. hircilactis and L. delbrueckii at 100 μg/ml showed significant anticancer activity on HT-29 cells with 58.4 % and 58.7 % respectively. These findings proved that exopolysaccharides from the two selected lactic acid bacterial strains could be explored as natural bioactive carbohydrate polymer for biomedical applications.}, } @article {pmid37555743, year = {2023}, author = {Lee, JE and Cho, HY and Lee, JH and Ahn, DU and Kim, KT and Paik, HD}, title = {The inhibitory effect of ovomucoid from egg white on the biofilm formation by Streptococcus mutans.}, journal = {Journal of the science of food and agriculture}, volume = {}, number = {}, pages = {}, doi = {10.1002/jsfa.12915}, pmid = {37555743}, issn = {1097-0010}, abstract = {BACKGROUND: Streptococcus mutans, the main pathogen associated with tooth decay, form cariogenic biofilms on tooth surfaces. Therefore, controlling oral biofilm helps prevent dental caries. Hen egg is a nutrient-dense food, and egg white is a good source of protein. Ovomucoid is one of the major proteins in egg white, with a 28 kDa molecular weight. The present study aimed to investigate the inhibitory effects of ovomucoid on the biofilm formation of S. mutans by suppressing virulence factors, including bacterial adherence, cellular aggregation, and exopolysaccharide (EPS) production.

RESULTS: The crystal violet staining showed that the biofilm formation by S. mutans was inhibited by ovomucoid at 0.25-1 mg/mL levels. The field emission scanning electron microscopy also confirmed this inhibition. In addition, ovomucoid reduced mature biofilm, water-insoluble EPS synthesis, and the metabolic activity of bacterial cells in the biofilm. The bacterial adhesion and aggregation abilities of S. mutans were also decreased in the presence of ovomucoid. Ovomucoid down-regulated the expression of the comDE and vicR genes involved in the two-component signal transduction system and the gtfA and ftf genes involved in EPS production.

CONCLUSION: Ovomucoid has the potential to be used as an anti-biofilm agent for dental caries treatment due to its inhibitory effects on the virulence factors of S. mutans. This article is protected by copyright. All rights reserved.}, } @article {pmid37553118, year = {2023}, author = {Zhao, RJ and Zhang, Z and Yang, SS and Min, G and Liu, SJ and Qiu, XT and Zhao, LT}, title = {Study on the performance of a new type of combined packing biofilm reactor treating wastewater.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-11}, doi = {10.1080/09593330.2023.2244708}, pmid = {37553118}, issn = {1479-487X}, abstract = {The present work investigates the performance of a biofilm reactor filled with a new type of combined packing used to treat wastewater and explores a new technology approach for the application of coral sand and waste non-woven fabric. The combined packing was made of coral sand and waste non-woven fabric, which was used as a biofilm carrier to treat sewage. The experimental results showed that the removal efficiencies of COD, NH4[+]-N and TN in the biofilm reactor containing the combined packing were 92.9%, 72.9% and 63.2%, respectively. The maximum removal efficiencies of COD, NH4[+]-N and TN in the biofilm reactor containing single packing were 89.0%, 63.4% and 55.2%, respectively. The properties of the combined packing were characterized by Fourier Transform Infrared (FTIR), specific surface area, SEM and dehydrogenase activity. Infrared analysis showed that there were hydroxyl, carboxyl and carbonyl groups on the surface of coral sand and non-woven fabric which were beneficial for biofilm growth and wastewater treatment. The large pores in the interior of coral sand and non-woven fabric could provide a comfortable environment for microbes to grow and reproduce. The dehydrogenase activity of the biofilm on the surface of coral sand in the third biofilm reactor was 49.91 μgTF·g[-1]·h[-1], which was significantly higher than that of the other two biofilm reactors. The new type of combined packing is suitable for biofilm carriers with low cost, which can be applied to actual sewage treatment projects. This study provides a reference for the practical application of the technique.}, } @article {pmid37552374, year = {2023}, author = {Dehari, D and Chaudhuri, A and Kumar, DN and Anjum, M and Kumar, R and Kumar, A and Kumar, D and Nath, G and Agrawal, AK}, title = {A Bacteriophage-Loaded Microparticle Laden Topical Gel for the Treatment of Multidrug-Resistant Biofilm-Mediated Burn Wound Infection.}, journal = {AAPS PharmSciTech}, volume = {24}, number = {6}, pages = {165}, pmid = {37552374}, issn = {1530-9932}, abstract = {Klebsiella pneumoniae is regarded as one of the most profound bacteria isolated from the debilitating injuries caused by burn wounds. In addition, the multidrug resistance (MDR) and biofilm formation make treating burn patients with clinically available antibiotics difficult. Bacteriophage therapy has been proven an effective alternative against biofilm-mediated wound infections caused by MDR bacterial strains. In the current study, the bacteriophage (BPKPФ1) against MDR Klebsiella pneumoniae was isolated and loaded into the chitosan microparticles (CHMPs), which was later incorporated into the Sepineo P 600 to convert into a gel (BPKPФ1-CHMP-gel). BPKPФ1 was characterized for lytic profile, morphological class, and burst size, which revealed that the BPKPФ1 belongs to the family Siphoviridae. Moreover, BPKPФ1 exhibited a narrow host range with 128 PFU/host cell of burst size. The BPKPФ1-loaded CHMPs showed an average particle size of 1.96 ± 0.51 μm, zeta potential 32.16 ± 0.41 mV, and entrapment efficiency in the range of 82.44 ± 1.31%. Further, the in vitro antibacterial and antibiofilm effectiveness of BPKPФ1-CHMPs-gel were examined. The in vivo potential of the BPKPФ1-CHMPs-gel was assessed using a rat model with MDR Klebsiella pneumoniae infected burn wound, which exhibited improved wound contraction (89.22 ± 0.48%) in 28 days with reduced inflammation, in comparison with different controls. Data in hand suggest the potential of bacteriophage therapy to be developed as personalized therapy in case of difficult-to-treat bacterial infections.}, } @article {pmid37551171, year = {2022}, author = {Loganathan, A and Nachimuthu, R}, title = {Antibiotic resistance, biofilm forming ability, and clonal profiling of clinical isolates of Staphylococcus aureus from southern and northeastern India.}, journal = {Asian biomedicine : research, reviews and news}, volume = {16}, number = {4}, pages = {191-199}, pmid = {37551171}, issn = {1875-855X}, abstract = {BACKGROUND: Staphylococcus aureus is a pathogen endemic in India and sometimes deadly for patients in intensive care units.

OBJECTIVES: To determine the antibiotic-resistance pattern, biofilm forming ability, and clonal type of S. aureus from isolates collected in Tamil Nadu (south) and the Mizoram (northeast) regions of India.

METHODS: We collected S. aureus isolates from diagnostic laboratories in Tamil Nadu and Mizoram. An antibiotic susceptibility test was performed according to Clinical Laboratory and Standards Institute methods. Antibiotic-resistant determinants such as mecA, mecC, blaZ, vanA, vanB, and vanC were confirmed by polymerase chain reaction (PCR). All isolates were further studied for biofilm forming ability. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used for clonal analysis.

RESULTS: A study of 206 clinical isolates showed 52.9% prevalence of methicillin-resistant S. aureus in Tamil Nadu and 49.4% in Mizoram. Minimum inhibitory concentration tests showed a high prevalence of 67% oxacillin resistance in isolates from Tamil Nadu and 49% in isolates from Mizoram. PCR showed 53% mecA in Tamil Nadu and 49% mecA in Mizoram. Vancomycin-intermediate resistance S. aureus (VISA) prevalence was lower in isolates from Tamil Nadu (4%) and Mizoram (5%). All methicillin-resistant S. aureus (MRSA) isolates formed biofilms. Clonal analysis revealed a genetic relatedness between the isolates.

CONCLUSIONS: The prevalence of MRSA is high in the regions studied, with most of the clinical isolates being multidrug resistant. Adopting appropriate community-based preventive measures and establishing antimicrobial stewardship is highly recommended to minimize the dissemination in antibiotic resistance.}, } @article {pmid37548082, year = {2023}, author = {Zackova Suchanova, J and Bilcke, G and Romanowska, B and Fatlawi, A and Pippel, M and Skeffington, A and Schroeder, M and Vyverman, W and Vandepoele, K and Kröger, N and Poulsen, N}, title = {Diatom adhesive trail proteins acquired by horizontal gene transfer from bacteria serve as primers for marine biofilm formation.}, journal = {The New phytologist}, volume = {}, number = {}, pages = {}, doi = {10.1111/nph.19145}, pmid = {37548082}, issn = {1469-8137}, support = {GOA01G01323//Bijzonder Onderzoeksfonds UGent/ ; INST 269/731-1 FUGG//Deutsche Forschungsgemeinschaft/ ; KR 1853/9-1//Deutsche Forschungsgemeinschaft/ ; PO 2256/1-1//Deutsche Forschungsgemeinschaft/ ; 100232736//European Regional Development Fund/ ; 1228423N//Fonds Wetenschappelijk Onderzoek/ ; 03Z22EB1//German Federal Ministry of Education and Research/ ; }, abstract = {Biofilm-forming benthic diatoms are key primary producers in coastal habitats, where they frequently dominate sunlit intertidal substrata. The development of gliding motility in raphid diatoms was a key molecular adaptation that contributed to their evolutionary success. However, the structure-function correlation between diatom adhesives utilized for gliding and their relationship to the extracellular matrix that constitutes the diatom biofilm is unknown. Here, we have used proteomics, immunolocalization, comparative genomics, phylogenetics and structural homology analysis to investigate the evolutionary history and function of diatom adhesive proteins. Our study identified eight proteins from the adhesive trails of Craspedostauros australis, of which four form a new protein family called Trailins that contain an enigmatic Choice-of-Anchor A (CAA) domain, which was acquired through horizontal gene transfer from bacteria. Notably, the CAA-domain shares a striking structural similarity with one of the most widespread domains found in ice-binding proteins (IPR021884). Our work offers new insights into the molecular basis for diatom biofilm formation, shedding light on the function and evolution of diatom adhesive proteins. This discovery suggests that there is a transition in the composition of biomolecules required for initial surface colonization and those utilized for 3D biofilm matrix formation.}, } @article {pmid37544532, year = {2023}, author = {Zhu, W and Van Tendeloo, M and De Paepe, J and Vlaeminck, SE}, title = {Comparison of typical nitrite oxidizing bacteria suppression strategies and the effect on nitrous oxide emissions in a biofilm reactor.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129607}, doi = {10.1016/j.biortech.2023.129607}, pmid = {37544532}, issn = {1873-2976}, abstract = {In mainstream partial nitritation/anammox (PN/A), suppression of nitrite oxidizing bacteria (NOB) and mitigation of N2O emissions are two essential operational goals. The N2O emissions linked to three typical NOB suppression strategies were tested in a covered rotating biological contactor biofilm system at 21 °C: (i) low dissolved oxygen (DO) concentrations, and treatments with (ii) free ammonia (FA), and (iii) free nitrous acids (FNA). Low emerged DO levels effectively minimized NOB activity and decreased N2O emissions, but NOB adaptation appeared after 200 days of operation. Further NOB suppression was successfully achieved by periodic (3 h per week) treatments with FA (29.3 ± 2.6 mg NH3-N L[-1]) or FNA (3.1 ± 0.3 mg HNO2-N L[-1]). FA treatment, however, promoted N2O emissions, while FNA did not affect these. Hence, biofilm PN/A should be operated at relatively low DO levels with periodic FNA treatment to maximize nitrogen removal efficiency while avoiding high greenhouse gas emissions.}, } @article {pmid37543134, year = {2023}, author = {Adamu Ugya, Y and Chen, H and Sheng, Y and Ajibade, FO and Wang, Q}, title = {A review of microalgae biofilm as an eco-friendly approach to bioplastics, promoting environmental sustainability.}, journal = {Environmental research}, volume = {}, number = {}, pages = {116833}, doi = {10.1016/j.envres.2023.116833}, pmid = {37543134}, issn = {1096-0953}, abstract = {In this comprehensive review, we delve into the challenges hindering the large-scale production of microalgae-based bioplastics, primarily focusing on economic feasibility and bioplastic quality. To address these issues, we explore the potential of microalgae biofilm cultivation as a sustainable and highly viable approach for bioplastic production. We present a proposed method for producing bioplastics using microalgae biofilm and evaluate its environmental impact using various tools such as life cycle analysis (LCA), ecological footprint analysis, resource flow analysis, and resource accounting. While pilot-scale and large-scale LCA data are limited, we utilize alternative indicators such as energy efficiency, carbon footprint, materials management, and community acceptance to predict the environmental implications of commercializing microalgae biofilm-based bioplastics. The findings of this study indicate that utilizing microalgae biofilm for bioplastic production offers significant environmental sustainability benefits. The system exhibits low energy requirements and a minimal carbon footprint. Moreover, it has the potential to address the issue of wastewater by utilizing it as a carbon source, thereby mitigating associated problems. However, it is important to acknowledge certain limitations associated with the method proposed in this review. Further research is needed to explore and engineer precise techniques for manipulating microalgae biofilm structure to optimize the accumulation of desired metabolites. This could involve employing chemical triggers, metabolic engineering, and genetic engineering to achieve the intended goals. In conclusion, this review highlights the potential of microalgae biofilm as a viable and sustainable solution for bioplastic production. While acknowledging the advantages, it also emphasizes the need for continued synthetic studies to enhance the efficiency and reliability of this approach. By addressing the identified drawbacks and maximizing the utilization of advanced techniques, we can further harness the potential of microalgae biofilm in contributing to a more environmentally friendly and economically feasible bioplastic industry.}, } @article {pmid37543075, year = {2023}, author = {Zhou, Z and Zhong, D and Zhang, Z and Ma, W and Chen, J and Zhuang, M and Li, F and Zhang, J and Zhu, Y and Su, P}, title = {Biofilm on the pipeline wall is an important transmission route of resistome in drinking water distribution system.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {}, number = {}, pages = {122311}, doi = {10.1016/j.envpol.2023.122311}, pmid = {37543075}, issn = {1873-6424}, abstract = {Due to the intensive use of antibiotics, the drinking water distribution system (DWDS) has become one of the hotspots of antibiotic resistance. However, little is known about the role of biofilm in the aspect of spreading resistance in DWDS. In present study, four lab-scale biological annular reactors (BAR) were constructed to investigate the transmission of ARGs exposed to a certain amount of antibiotic (sulfamethoxazole) synergistic disinfectants. It was emphasized that pipe wall biofilm was an important way for ARGs to propagate in the pipeline, and the results were quantified by constructing an operational taxonomic unit (OTU) network map. The network analysis results showed the biofilm contribution to waterborne bacteria was finally estimated to be 51.45% and 34.27% in polyethylen (PE) pipe and ductile iron (DI) pipe, respectively. The proportion of vertical gene transfer (VGT) in biofilm was higher than that in water, and the occurrence of this situation had little relationship with the selection of pipe type. Overall, this study revealed how biofilm promoted the transmission of resistome in bulk water, which can provide insights into assessing biofilm-associated risks and optimizing pipe material selection for biofilm control in DWDS.}, } @article {pmid37543054, year = {2023}, author = {Dias Gomes da Silva, N and Sérgio da Silva Santos, P and Carolina Magalhães, A and Afonso Rabelo Buzalaf, M}, title = {Antibacterial, antibiofilm and anticaries effect of BioXtra® mouthrinse for head and neck cancer (HNC) patients under a microcosm biofilm model.}, journal = {Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology}, volume = {}, number = {}, pages = {109846}, doi = {10.1016/j.radonc.2023.109846}, pmid = {37543054}, issn = {1879-0887}, abstract = {BACKGROUND AND PURPOSE: Considering the lack of studies investigating salivary substitutes to control post-radiation caries for patients with head and neck cancer (HNC), this study aimed to evaluate the antibacterial, antibiofilm, and anticaries effects of BioXtra® on the microcosm biofilm formed on different enamel types (non-irradiated and irradiated) and from distinct saliva sources (control and HNC patients).

MATERIALS AND METHODS: Non-irradiated and irradiated enamel specimens were treated with BioXtra®, phosphate-buffered-saline (PBS; negative control), or 0.12% chlorhexidine (CHX; positive control) for 1 min. Biofilm was produced from human saliva (healthy participants with normal salivary flow for the control group or irradiated HNC patients with hyposalivation for the HNC group), mixed with McBain saliva, under 0.2% sucrose exposure, daily submitted to the treatments (1 min), for 5 days. Bacterial metabolic activity, biofilm viability, CFU counting, and enamel demineralization were determined.

RESULTS: BioXtra® significantly reduced the bacterial metabolic activity for both enamel types and the inoculum sources, being more effective for the irradiated enamel or for the saliva from the control group. Similarly, BioXtra® significantly reduced the biofilm viability, the CFU for total microorganisms, mutans streptococci, and lactobacilli, and was able to significantly reduce the mineral loss and the lesion depth compared to PBS. CHX was an effective treatment to significantly reduce all parameters, performing better than BioXtra® and reinforcing its reliable efficiency as a positive control.

CONCLUSION: Regardless of the enamel type and the inoculum source, BioXtra® presented antibacterial, antibiofilm, and anticaries effects under this experimental model, which should be confirmed in further clinical studies.}, } @article {pmid37542660, year = {2023}, author = {Bem, JSP and Lacerda, NGS and Polizello, ACM and Cabral, H and da Rosa-Garzon, NG and Aires, CP}, title = {Mutanase from Trichoderma harzianum inductively Produced by Mutan: Short-Term Treatment to Degrade Mature Streptococcus mutans Biofilm.}, journal = {Current microbiology}, volume = {80}, number = {9}, pages = {312}, pmid = {37542660}, issn = {1432-0991}, support = {2019/19162-7//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2020/ 07315-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {This study aimed to evaluate the disruptive effect of fungal mutanase against cariogenic biofilm after short-term treatment. For that, mature Streptococcus mutans biofilms (n = 9) were exposed to active or inactivated enzymes produced by Trichoderma harzianum for 1 min, two times per day. Biofilms were analyzed by amount of matrix water-insoluble polysaccharides, bacterial viability, acidogenicity, and morphology by scanning electron microscopy (SEM). The group treated with active enzymes (AE) had a significantly lower amount of insoluble polysaccharides (893.30 ± 293.69) when compared to the negative control group (NaCl, 2192.59 ± 361.96), yet no significant difference was found when comparing to the positive control group (CHX, 436.82 ± 151.07). Also, there was no significant effect on bacteria metabolism and viability (P-value < 0.05). Data generated by the quantitative analysis were confirmed through scanning electron microscopy images. Thus, fungal mutanase degraded the biofilm after a short-term treatment without interfering with bacterial viability and metabolism. Such findings offer insight to the development of routine oral care products containing this input.}, } @article {pmid37542577, year = {2023}, author = {Sharma, A and Bansal, S and Kumari, N and Vashistt, J and Shrivastava, R}, title = {Comparative proteomic investigation unravels the pathobiology of Mycobacterium fortuitum biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37542577}, issn = {1432-0614}, abstract = {Biofilm formation by Mycobacterium fortuitum causes serious threats to human health due to its increased contribution to nosocomial infections. In this study, the first comprehensive global proteome analysis of M. fortuitum was reported under planktonic and biofilm growth states. A label-free Q Exactive Quadrupole-Orbitrap tandem mass spectrometry analysis was performed on the protein lysates. The differentially abundant proteins were functionally characterized and re-annotated using Blast2GO and CELLO2GO. Comparative analysis of the proteins among two growth states provided insights into the phenotypic switch, and fundamental pathways associated with pathobiology of M. fortuitum biofilm, such as lipid biosynthesis and quorum-sensing. Interaction network generated by the STRING database revealed associations between proteins that endure M. fortuitum during biofilm growth state. Hypothetical proteins were also studied to determine their functional alliance with the biofilm phenotype. CARD, VFDB, and PATRIC analysis further showed that the proteins upregulated in M. fortuitum biofilm exhibited antibiotic resistance, pathogenesis, and virulence. Heatmap and correlation analysis provided the biomarkers associated with the planktonic and biofilm growth of M. fortuitum. Proteome data was validated by qPCR analysis. Overall, the study provides insights into previously unexplored biochemical pathways that can be targeted by novel inhibitors, either for shortened treatment duration or for eliminating biofilm of M. fortuitum and related nontuberculous mycobacterial pathogens. KEY POINTS: • Proteomic analyses of M. fortuitum reveals novel biofilm markers. • Acetyl-CoA acetyltransferase acts as the phenotype transition switch. • The study offers drug targets to combat M. fortuitum biofilm infections.}, } @article {pmid37542538, year = {2023}, author = {Niu, J and Chen, D and Shang, C and Xiao, L and Wang, Y and Zeng, W and Zheng, X and Chen, Z and Du, X and Chen, X}, title = {Niche Differentiation of Biofilm Microorganisms in a Full-scale Municipal Drinking Water Distribution System in China and Their Implication for Biofilm Control.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, pmid = {37542538}, issn = {1432-184X}, abstract = {Biofilms on the inner surface of a drinking water distribution system (DWDS) affect water quality and stability. Understanding the niche differentiation of biofilm microbial communities is necessary for the efficient control of DWDS biofilms. However, biofilm studies are difficult to conduct in the actual DWDS because of inaccessibility to the pipes buried underground. Taking the opportunity of infrastructure construction and relevant pipeline replacement in China, biofilms in a DWDS (a water main and its branch pipes) were collected in situ, followed by analysis on the abundances and community structures of bacterial and archaeal using quantitative PCR and high-throughput sequencing, respectively. Results showed that archaea were detected only in the biofilms of the water main, with a range of 9.4×10[3]~1.1×10[5] copies/cm[2]. By contrast, bacteria were detected in the biofilms of branch pipes and the distal part of the water main, with a range of 8.8×10[3]~9.6×10[6] copies/cm[2]. Among the biofilm samples, the archaeal community in the central part of the water main showed the highest richness and diversity. Nitrosopumilus was found to be predominant (86.22%) in the biofilms of the proximal part of the water main. However, Methanobrevibacter (87.15%) predominated in the distal part of the water main. The bacterial community of the water main and branch pipes was primarily composed of Firmicutes and Proteobacteria at the phylum level, respectively. Regardless of archaea or bacteria, only few operational taxonomic units (OTUs) (<0.5% of total OTUs) were shared by all the biofilms, indicating the niche differentiation of biofilm microorganisms. Moreover, the high Mn content in the biofilms of the distal sampling location (D3) in the water main was linked to the predominance of Bacillus. Functional gene prediction revealed that the proportion of infectious disease-related genes was 0.44-0.67% in the tested biofilms. Furthermore, functional genes related to the resistance of the bacterial community to disinfections and antibiotics were detected in all the samples, that is, glutathione metabolism-relating genes (0.14-0.65%) and beta-lactam resistance gene (0.01-0.05%). The results of this study indicate the ubiquity of archaea and bacteria in the biofilms of water main and branch pipes, respectively, and pipe diameters could be a major influencing factor on bacterial community structure. In the water main, the key finding was the predominant existence of archaea, particularly Nitrosopumilus and methanogen. Hence, their routine monitoring and probable influences on water quality in pipelines with large diameter should be given more attention. Besides, since Mn-related Bacillus and suspected pathogenic Enterococcus were detected in the biofilm, supplementation of disinfectant may be a feasible strategy for inhibiting their growth and ensuring water quality. In addition, the monitoring on their abundance variation could help to determine the frequency and methods of pipeline maintenance.}, } @article {pmid37541550, year = {2023}, author = {Zheng, J and Zhang, Q and Ding, Y and Liu, W and Chen, L and Cai, T and Ji, XM}, title = {Microbial interactions play a keystone role in rapid anaerobic ammonium oxidation sludge proliferation and biofilm formation.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129612}, doi = {10.1016/j.biortech.2023.129612}, pmid = {37541550}, issn = {1873-2976}, abstract = {Two mature anaerobic ammonium oxidation (anammox) consortia with high/low relative abundance of anammox bacteria were inoculated for the rapid sludge proliferation and biofilm formation in this study, named up-flow anaerobic sludge blanket reactor (UASB1) (high) and UASB2 (low), respectively. Results showed that the nitrogen removal efficiency of UASB2 reached 90.94% after the 120-day operation, which was 13% higher than that of UASB1. Moreover, its biomass amounts were 22.18% (biofilm) and 40.96% (flocs) higher than that of UASB1, respectively. Ca. Kuenenia possessed relative abundances of 29.32% (flocs), 27.42% (biofilm) and 31.56% (flocs), 35.20% (biofilm) in the UASB1 and UASB2, respectively. The relative abundances of genes involved in anammox transformation (hzs, nir) and carbon metabolism (fdh, GlgA/B/C, acs) were higher in the UASB2, indicating that Ca. Kuenenia might produce acetate and glycogen to enhance microbial interactions. These findings emphasized the importance of microbial interactions in anammox sludge proliferation and biofilm formation.}, } @article {pmid37541520, year = {2023}, author = {Ge, Z and Ma, Z and Zou, J and Zhang, Y and Li, Y and Zhang, L and Zhang, J}, title = {Purification of aquaculture wastewater by macrophytes and biofilm systems: Efficient removal of trace antibiotics and enrichment of antibiotic resistance genes.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {165943}, doi = {10.1016/j.scitotenv.2023.165943}, pmid = {37541520}, issn = {1879-1026}, abstract = {The purification performance of aquaculture wastewater and the risk of antibiotic resistance genes (ARGs) dissemination in wetlands dominated by macrophytes remain unclear. Here, the purification effects of different macrophytes and biofilm systems on real aquaculture wastewater were investigated, as well as the distribution and abundance of ARGs. Compared to the submerged macrophytes, artificial macrophytes exhibited higher removal rates of TOC (58.80 ± 5.04 %), TN (74.50 ± 2.50 %), and TP (77.33 ± 11.66 %), and achieved approximately 79.92 % removal of accumulated trace antibiotics in the surrounding water. Additionally, the biofilm microbial communities on the surface of artificial macrophytes exhibited higher microbial diversity with fewer antibiotic-resistant bacteria (ARB) enrichment from the surrounding water. The absolute abundance of ARGs (sul1, sul2, and intI1) in the mature biofilm to be one to two orders of magnitude higher than that in the water. Although biofilms could decrease ARGs in the surrounding water by enriching ARB, the intricate network structure of biofilms further facilitated the proliferation of ARB and the dissemination of ARGs in water. Network analysis suggested that Proteobacteria and Firmicutes phyla were dominant and potential carriers of ARGs, contributing 69.00 % and 16.70 %, respectively. Our findings highlight that macrophytes and biofilm systems have great performance on aquaculture wastewater purification, but with high risk of ARGs.}, } @article {pmid37540982, year = {2023}, author = {Tang, CC and Zhang, BC and Yao, XY and Sangeetha, T and Zhou, AJ and Liu, W and Ren, YX and Li, Z and Wang, A and He, ZW}, title = {Natural zeolite enhances anaerobic digestion of waste activated sludge: Insights into the performance and the role of biofilm.}, journal = {Journal of environmental management}, volume = {345}, number = {}, pages = {118704}, doi = {10.1016/j.jenvman.2023.118704}, pmid = {37540982}, issn = {1095-8630}, abstract = {Anaerobic digestion is widely employed for the treatment of waste activated sludge (WAS) due to its advantages like simultaneous energy recovery and sludge stabilization, promoting carbon-neutral operation of wastewater treatment plants. Natural zeolite, a low-cost and eco-friendly additive, has the potential to improve methane production from anaerobic digestion. This study investigated the effects of natural zeolite on anaerobic digestion when the substrate was WAS. It was found that methane production potential in response to natural zeolite was dosage-dependent. The optimal dosage was 0.1 g zeolite/g volatile suspended solids (VSS), with a methane yield of 181.89 ± 6.75 mL/g VSS, which increased by 20.1% compared to that of the control. Although the methane yields with other dosages of natural zeolite were higher than that of control, they were lesser than that with 0.1 g zeolite/g VSS. Natural zeolite affected transfer and conversion of proteins much more than polysaccharides in liquid phase and extracellular polymeric substances. In anaerobic digestion, natural zeolite had with little effects on WAS solubilization, while it improved hydrolysis, acidification, and methanogenesis. The dosages of natural zeolite did have significant effects on bacterial communities in biofilm rather than suspension, while the archaeal communities in biofilm and suspension were all greatly related to natural zeolite dosages. The developed biofilms promoted richness and functionality of microbial communities. The syntrophic metabolism relationships between methanogens and bacteria were improved, which was proved by selective enrichment of Methanosarcina, Syntrophomonas, and Petrimonas. The findings of this work provided some new solutions for promoting methane production from WAS, and the roles of natural zeolite in anaerobic digestion.}, } @article {pmid37540453, year = {2023}, author = {Rastegar, E and Malekzadegan, Y and Khashei, R and Hadi, N}, title = {Quinolone resistance and biofilm formation capability of uropathogenic Escherichia coli isolates from an Iranian inpatients' population.}, journal = {Molecular biology reports}, volume = {}, number = {}, pages = {}, pmid = {37540453}, issn = {1573-4978}, support = {Grant number 15584//Shiraz University of Medical Sciences/ ; }, abstract = {BACKGROUND: Uropathogenic Escherichia coli (UPEC) is a major pathogen of the urinary tract infection (UTI), and biofilm formation is crucial as it facilitates the colonization in the urinary tract. We aimed to investigate the antibiotic susceptibility pattern, biofilm formation capability, distribution of quinolone resistance genes, and phylogenetic groups among UPEC isolates from an Iranian inpatients' community.

METHODS AND RESULTS: A collection of 126 UPEC obtained from hospitalized patients with symptomatic UTI at 3 teaching hospitals during 2016 were included. Antibiogram of all isolates against quinolone and fluoroquinolones was performed using the disk diffusion method. Phylogenetic groups and qnr A, B, and S genes were assessed by PCR. Susceptibility pattern showed that more than 50% and 81% of the isolates were resistant to fluoroquinolones and quinolones, correspondingly. The frequency of qnrS and qnrB genes was 22% and 13.5%, correspondingly. Our result indicated no significant association between the presence of fluoroquinolone genes and antibiotic resistance to them. The frequent common phylogroup was B2 (84.1%), followed by D (10.3%), A (3.2%) and B1 (2.4%) groups. Indeed, 80.2% of the isolates were biofilm producers, so that 42.1%, 16.7% and 21.4% of them were classified as weak, moderate and strong producers, respectively.

CONCLUSIONS: Our results showed considerable fluoroquinolone and quinolone resistance among UPEC along with a remarkable rate of biofilm-producing isolates from symptomatic hospitalized patients, making them a serious health concern in the region. This survey highlights the need for awareness on quinolone resistance and careful prescription of them by physicians.}, } @article {pmid37540386, year = {2023}, author = {Zhang, J and Sun, J and Zhang, Y and Zhang, M and Liu, X and Yang, L and Yin, Y}, title = {Dehydrocostus lactone inhibits Candida albicans growth and biofilm formation.}, journal = {AMB Express}, volume = {13}, number = {1}, pages = {82}, pmid = {37540386}, issn = {2191-0855}, support = {2019SCZT053//the Special Fund for Medical Professionals of Jilin Province/ ; }, abstract = {Candida albicans infections are threatening public health but there are only several antifungal drugs available. This study was to assess the effects of dehydrocostus lactone (DL) on the Candida albicans growth and biofilms Microdilution assays revealed that DL inhibits a panel of standard Candida species, including C. albicans, as well as 9 C. albicans clinical isolates. The morphological transition of C. albicans in RPMI-1640 medium and the adhesion to polystyrene surfaces can also be decreased by DL treatment, as evidenced by microscopic, metabolic activity and colony forming unit (CFU) counting assays. The XTT assay and microscopy inspection demonstrated that DL can inhibit the biofilms of C. albicans. Confocal microscopy following propidium iodide (PI) staining and DCFH-DA staining after DL treatment revealed that DL can increase the membrane permeability and intracellular reactive oxygen species (ROS) production. N-acetyl-cysteine could mitigate the inhibitory effects of DL on growth, morphological transition and biofilm formation, further confirming that ROS production induced by DL contributes to its antifungal and antibiofilm effects. This study showed that DL demonstrated antifungal and antibiofilm activity against C. albicans. The antifungal mechanisms may involve membrane damage and ROS overproduction. This study shows the potential of DL to fight Candida infections.}, } @article {pmid37540315, year = {2023}, author = {Wu, Z and Chi, H and Han, T and Li, G and Wang, J and Chen, W}, title = {Differences of Escherichia coli isolated from different organs of the individual sheep: molecular typing, antibiotics resistance, and biofilm formation.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {37540315}, issn = {1874-9356}, support = {2020AB025//Key Scientific and Technological Project of XPCC/ ; TDGRI20210//Postgraduate Student Research and Innovation Project of Tarim University/ ; }, abstract = {Despite numerous studies on Escherichia coli (E. coli) from sheep, there have been few reports on the characterization of E. coli isolates from various organs of individual sheep until now. The present study conducted molecular typing, antibiotics resistance, biofilm formation, and virulence genes on E. coli isolated from 57 freshly slaughtered apparently healthy sheep carcasses, gallbladders, fecal samples, and mesenteric lymph nodes (MLNs). The results demonstrated that the detection rate of R1 LPS core type in E. coli isolated from fecal samples (70.83%) was higher than that from other organs, but the detection rate of antibiotic resistance genes was lower (P < 0.05). The predominant phylogenetic group of E. coli isolated from the carcasses was group B1 (93.33%), and the detection rate of multidrug-resistance phenotype (80%) and the resistance rate of E. coli was higher than that from other organs (P < 0.05). Interestingly, the intensity of biofilm formation of E. coli isolated from MLNs was higher than that from other organs (P < 0.05). However, except for ibeB, the detection rates of virulence genes did not differ in E.coli isolated from different organs. In conclusion, differences were noted in these parameters of E. coli isolated from different organs of individual sheep. Therefore, the data may contain considerable mistakes concerning the actual situation in the host if we only analyze the data of E. coli isolated from feces or carcasses.}, } @article {pmid37538844, year = {2023}, author = {Abou Elez, RMM and Elsohaby, I and Al-Mohammadi, AR and Seliem, M and Tahoun, ABMB and Abousaty, AI and Algendy, RM and Mohamed, EAA and El-Gazzar, N}, title = {Antibacterial and anti-biofilm activities of probiotic Lactobacillus plantarum against Listeria monocytogenes isolated from milk, chicken and pregnant women.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1201201}, pmid = {37538844}, issn = {1664-302X}, abstract = {Listeria monocytogenes (L. monocytogenes) is a foodborne pathogen that poses significant risks to public health and food safety. The present study aimed to identify the presence of Listeria spp. in various samples, including pasteurized milk, chicken fillets, and stool samples from pregnant women in Sharkia Governorate, Egypt. Additionally, the study identified the serotypes, virulence-associated genes, antimicrobial resistance patterns, and biofilm formation in L. monocytogenes isolates. Moreover, the antibacterial and anti-biofilm activity of Lactobacillus plantarum ATCC 14917 (L. plantarum) against L. monocytogenes isolates was investigated. A cross-sectional study was conducted from August 2021 to January 2022 to collect 300 samples of pasteurized milk, chicken fillets, and stool from pregnant women admitted to outpatient clinics of hospitals. The results showed that 32.7% of the samples were positive for Listeria spp., including L. innocua (48.9%), L. monocytogenes (26.5%), L. ivanovii (14.3%), L. grayi (5.1%), and L. welshimeri (5.1%). Among all L. monocytogenes isolates, hlyA, actA, inlC, and inlJ virulence-associated genes were detected. However, the virulence genes plcB, iap, and inlA were found in 10 (38.5%), 8 (30.8%), and 25 (96.2%) isolates, respectively. The L. monocytogenes isolates classified into four serotypes (1/2a, 1/2b, 1/2c, and 4b), with 1/2a and 4b each identified in 30.8% of the isolates, while 1/2b and 1/2c were identified in 19.2% of the isolates. All L. monocytogenes isolates showed 100% resistance to streptomycin, kanamycin, and nalidix acid, and 92.3% of isolates showed gentamicin resistance. However, all isolates were susceptible to ampicillin and ampicillin/sulbactam. Multidrug resistance (MDR) was observed in 20 (76.9%) L. monocytogenes isolates. The biofilm formation ability of 26 L. monocytogenes isolates was evaluated at different incubation temperatures. At 4°C, 25°C, and 37°C, 53.8, 69.2, and 80.8% of the isolates, respectively, were biofilm producers. Furthermore, 23.1% were strong biofilm producers at both 4°C and 25°C, while 34.6% were strong biofilm formers at 37°C. Treating L. monocytogenes isolates with L. plantarum cell-free supernatant (CFS) reduced the number of biofilm-producing isolates to 15.4, 42.3, and 53.8% at 4°C, 25°C, and 37°C, respectively. L. plantarum's CFS antibacterial activity was tested against six virulent, MDR, and biofilm-forming L. monocytogenes isolates. At a concentration of 5 μg/mL of L. plantarum CFS, none of the L. monocytogenes isolates exhibited an inhibition zone. However, an inhibition zone was observed against L. monocytogenes strains isolated from pasteurized milk and pregnant women's stools when using a concentration of 10 μg/mL. Transmission electron microscopy (TEM) revealed that L. plantarum CFS induced morphological and intracellular structural changes in L. monocytogenes. In conclusion, this study identified virulent MDR L. monocytogenes isolates with strong biofilm-forming abilities in food products in Egypt, posing significant risks to food safety. Monitoring the prevalence and antimicrobial resistance profile of L. monocytogenes in dairy and meat products is crucial to enhance their safety. Although L. plantarum CFS showed potential antibacterial and anti-biofilm effects against L. monocytogenes isolates, further research is needed to explore its full probiotic potential.}, } @article {pmid37537876, year = {2023}, author = {Silva E Carvalho, I and Pratavieira, S and Salvador Bagnato, V and Alves, F}, title = {Sonophotodynamic inactivation of Pseudomonas aeruginosa biofilm mediated by curcumin.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-11}, doi = {10.1080/08927014.2023.2241385}, pmid = {37537876}, issn = {1029-2454}, abstract = {The inactivation of Pseudomonas aeruginosa biofilm is a major challenge, as biofilms are less responsive to conventional treatments and responsible for persistent infections. This has led to the investigation of alternative approaches for biofilm control such as photodynamic (PDI) and sonodynamic (SDI) inactivation. The combination of them, known as Sonophotodynamic Inactivation (SPDI), has improved the effectiveness of the process. Curcumin, a well-established photosensitizer, has been identified as a potential sonosensitizer. This study evaluated the most effective combination for SPDI against P. aeruginosa biofilms in vitro, varying curcumin concentrations and ultrasound intensities. The results indicated that the inactivation was directly proportional to the curcumin concentration. Using curcumin 120 µM and 3.0 W.cm[-2] of ultrasound intensity, SPDI demonstrated the highest and the best synergistic results, equivalent to 6.9 ± 2.1 logs of reduction. PDI reduced 0.7 ± 0.9 log and SDI had no effect. In conclusion, SPDI with curcumin is a promising approach for biofilm inactivation.}, } @article {pmid37536571, year = {2023}, author = {Jeong, GJ and Khan, F and Tabassum, N and Cho, KJ and Kim, YM}, title = {Controlling biofilm and virulence properties of Gram-positive bacteria by targeting wall teichoic acid and lipoteichoic acid.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106941}, doi = {10.1016/j.ijantimicag.2023.106941}, pmid = {37536571}, issn = {1872-7913}, abstract = {Wall teichoic acid (WTA) and lipoteichoic acid (LTA) are structural components of Gram-positive bacteria's peptidoglycan and cell membrane, which are mostly anionic glycopolymers. WTA confers numerous physiological, virulence, and pathogenic features to bacterial pathogens. It controls cell shape, cell division, and the localization of autolytic enzymes and ion homeostasis. In the context of virulence and pathogenicity, it aids bacterial cell attachment and colonization and protects against the host defense system and antibiotics. Having such a broad function in pathogenic bacteria's lifecycle, WTA/LTA become one of the potential targets for antibacterial agents to reduce bacterial infection in the host. The number of reports for targeting the WTA/LTA pathway has risen, mostly by focusing on three distinct targets: antivirulence targets, β-lactam potentiator targets, and essential targets. The current review looked at the role of WTA/LTA in biofilm development and virulence in a range of Gram-positive pathogenic bacteria. Furthermore, alternate strategies, such as the application of natural and synthetic compounds that target the WTA/LTA pathway, have been thoroughly discussed. Moreover, the application of nanomaterials and a combination of drugs have also been discussed as a viable method for targeting the WTA/LTA in numerous Gram-positive bacteria. In addition, a future perspective for controlling bacterial infection by targeting the WTA/LTA is proposed.}, } @article {pmid37536538, year = {2023}, author = {Mou, Y and Liu, N and Lu, T and Jia, C and Xu, C and Song, M}, title = {The effects of carbon nitrogen ratio and salinity on the treatment of swine digestion effluent simultaneously producing bioenergy by microalgae biofilm.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139694}, doi = {10.1016/j.chemosphere.2023.139694}, pmid = {37536538}, issn = {1879-1298}, abstract = {In order to remove high concentrations of ammonia nitrogen (NH4[+]-N) and refractory sulfamethazine (SM2) from swine digestion effluent, different carbon/nitrogen (C/N) ratios and salinity were used to determine the effects of pollutants removal in the microalgae biofilm system. Microalgae biofilm treatment under optimal environmental conditions in synthetic swine digestion effluent were C/N ratio of 20 and salinity of 140 mM. In order to make the actual swine digestion effluent discharge up to the standard, three different two-cycle treatments (suspended microalgae, microalgae biofilm, microalgae biofilm under the optimal conditions) were studied. The results showed that after two-cycle treatment with microalgae biofilm under the optimal conditions, the actual swine digestion effluent levels of total nitrogen (TN), NH4[+]-N, total phosphorus (TP), chemical oxygen demand (COD), SM2 were 22.65, 9.32, 4.11, 367.28, and 0.99 mg L[-1], respectively, which could satisfy the discharge standards for livestock and poultry wastewater in China. At the same time, first-order kinetic simulation equations suggested a degradation half-life of 4.85 d for SM2 under optimal conditions in microalgae biofilm, and microbial community analysis indicated that the dominant genus was Halomonas. Furthermore, 35.66% of lipid, 32.56% of protein and 18.44% of polysaccharides were harvested after two-cycle in microalgae biofilm treatment under optimal environmental conditions. These results indicated that the regulation of C/N and salinity in microalgae biofilm for the treatment of swine digestion effluent was a high-efficiency strategy to simultaneously achieve wastewater treatment and bioenergy production.}, } @article {pmid37536430, year = {2023}, author = {Cho, MY and Lee, ES and Jung, HI and Kim, BI}, title = {Anti-biofilm activity of a novel nanoemulsion containing Curcuma xanthorrhiza oil.}, journal = {Journal of dentistry}, volume = {}, number = {}, pages = {104647}, doi = {10.1016/j.jdent.2023.104647}, pmid = {37536430}, issn = {1879-176X}, abstract = {OBJECTIVES: We aimed to solubilize Curcuma xanthorrhiza oil (CXO) using nanoemulsification and evaluate its inhibitory effects against biofilm formation.

METHODS: The components of CXO were evaluated through high-performance liquid chromatography (HPLC) analysis. Healthy human saliva was inoculated onto hydroxyapatite discs to form microcosm biofilms for four days and treated six times with each antimicrobial agent: distilled water (DW), CXO emulsion (EM), CXO nanoemulsion (NE), and positive controls (Listerine, chlorhexidine). Biofilm fluorescence imaging was performed using quantitative light-induced fluorescence, and cell viability and dry-weight measurements were obtained. We compared the bacterial cell and extracellular polysaccharide (EPS) biovolume and thickness using confocal laser scanning microscopy (CLSM).

RESULTS: HPLC analysis revealed that CXO was composed of approximately 47% xanthorrhizol. Compared with DW, NE exhibited significantly lower red fluorescence intensity and area (42% and 37%, p < 0.001 and p < 0.001, respectively), and reduced total and aciduric bacterial cell viability (7.3% and 3.9%, p < 0.001, p = 0.01, respectively). Furthermore, the bacterial cell and EPS biovolume and thickness in NE decreased by 40-80% compared to DW, similar to chlorhexidine. Conversely, EM showed a significant difference only in cell viability against total bacteria when compared with DW (p = 0.003), with EPS biovolume and thickness exhibiting higher values than DW.

CONCLUSIONS: Nanoemulsification successfully solubilized CXO and demonstrated superior anti-biofilm effects compared to the emulsion form.

CLINICAL SIGNIFICANCE: These findings suggest the potential use of NE as a novel antimicrobial agent for preventing oral diseases.}, } @article {pmid37537345, year = {2023}, author = {Costa-Gutierrez, SB and Raimondo, EE and Vincent, PA and de Cristóbal, RE}, title = {Importance of biofilm formation for promoting plant growth under salt stress in Pseudomonas putida KT2440.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300215}, pmid = {37537345}, issn = {1521-4028}, support = {PICT 3552/2018, PICT 2020/02005//Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT)/ ; //BID 3071/ ; }, abstract = {An underutilized experimental design was employed to isolate adapted mutants of the model bacterium Pseudomonas putida KT2440. The design involved subjecting a random pool of mini-Tn5 mutants of P. putida KT2440 to multiple rounds of selection in the rhizosphere of soybean plants irrigated with a NaCl solution. The isolated adapted mutants, referred to as MutAd, exhibited a mutation in the gene responsible for encoding the membrane-binding protein LapA, which plays a role in the initial stages of biofilm formation on abiotic surfaces. Two MutAd bacteria, MutAd160 and MutAd185, along with a lapA deletion mutant, were selected for further investigation to examine the impact of this gene on salt tolerance, rhizosphere fitness, production of extracellular polymeric substances (EPS), and promotion of plant growth. Despite the mutants' inability to form biofilms, they were able to attach to soybean seeds and roots. The MutAd bacteria demonstrated an elevated production of EPS when cultivated under saline conditions, which likely compensated for the absence of biofilm formation. MutAd185 bacteria exhibited enhanced root attachment and promoted the growth of soybean plants in slightly saline soils. The proposed experimental design holds promise for expediting bacterial adaptation to the rhizosphere of plants under specific environmental conditions, identifying genetic mutations that enhance bacterial fitness in those conditions, and thereby increasing their capacity to promote plant growth.}, } @article {pmid37537176, year = {2023}, author = {Nucci, A and Rocha, EPC and Rendueles, O}, title = {Latent evolution of biofilm formation depends on life-history and genetic background.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {53}, pmid = {37537176}, issn = {2055-5008}, support = {ANR-10-LABX-62-IBEID//Agence Nationale de la Recherche (French National Research Agency)/ ; ANR-10-LABX-62-IBEID//Agence Nationale de la Recherche (French National Research Agency)/ ; EQU201903007835//Fondation pour la Recherche Médicale (Foundation for Medical Research in France)/ ; }, abstract = {Adaptation to one environment can often generate phenotypic and genotypic changes which impact the future ability of an organism to thrive in other environmental conditions. In the context of host-microbe interactions, biofilm formation can increase survival rates in vivo upon exposure to stresses, like the host's immune system or antibiotic therapy. However, how the generic process of adaptation impacts the ability to form biofilm and how it may change through time has seldomly been studied. To do so, we used a previous evolution experiment with three strains of the Klebsiella pneumoniae species complex, in which we specifically did not select for biofilm formation. We observed that changes in the ability to form biofilm happened very fast at first and afterwards reverted to ancestral levels in many populations. Biofilm changes were associated to changes in population yield and surface polysaccharide production. Genotypically, mutations in the tip adhesin of type III fimbriae (mrkD) or the fim switch of type I fimbriae were shaped by nutrient availability during evolution, and their impact on biofilm formation was dependent on capsule production. Analyses of natural isolates revealed similar mutations in mrkD, suggesting that such mutations also play an important role in adaptation outside the laboratory. Our work reveals that the latent evolution of biofilm formation, and its temporal dynamics, depend on nutrient availability, the genetic background and other intertwined phenotypic and genotypic changes. Ultimately, it suggests that small differences in the environment can alter an organism's fate in more complex niches like the host.}, } @article {pmid37535660, year = {2023}, author = {Rubio-Mendoza, D and Córdova-Fletes, C and Martínez-Meléndez, A and Morfín-Otero, R and Maldonado-Garza, HJ and Garza-González, E}, title = {Transcriptomic analysis of biofilm formation in strains of Clostridioides difficile associated with recurrent and non-recurrent infection reveals potential candidate markers for recurrence.}, journal = {PloS one}, volume = {18}, number = {8}, pages = {e0289593}, doi = {10.1371/journal.pone.0289593}, pmid = {37535660}, issn = {1932-6203}, abstract = {The transcriptomic profile in a biofilm model of ribotypes (RT) 001 and 027 associated with recurrent Clostridioides difficile infection (R-CDI) and not associated with recurrent (NR)-CDI was analyzed to identify genes that may favor the recurrence. Twenty strains were selected, 10 RT001 and 10 RT027. From each ribotype, 5 were R-CDI and 5 NR-CDI. Biofilm and nonadherent cells were prepared from each clinical isolate, and the RNA was extracted. RNA samples were pooled in 8 combinations implying ribotype, recurrence, and biofilm formation. Each pool was separately labeled with Cy3 dye and hybridized on a microarray designed for this study. Slides were scanned, analyzed, and gene expression was compared between unique and grouped pools using the Student's t-test with Benjamini-Hochberg correction when appropriate. Validation was carried out by qRT-PCR for selected genes. Results: After comparisons of differentially expressed genes from both ribotypes of R-CDI strains (nonadherent cells vs. biofilm) and both ribotypes in biofilm (R-CDI vs. NR-CDI), we found 3 genes over-expressed and 1 under-expressed in common (adj. p ≤ 0.05). Overexpressed genes were CAJ70148 (a putative dehydrogenase), CAJ68100 (a secretion type II system protein from the GspH (pseudopilins) family), and CAJ69725 (a putative membrane protein); under-expressed was CAJ68151 (a segregation and condensation protein A). Because CAJ70148, CAJ68100, CAJ69725 and CAJ68151 were differentially expressed in biofilm in strains associated with R-CDI, they may support the biofilm favoring the recurrence of CDI. However, further studies will be needed for poorly studied genes.}, } @article {pmid37533040, year = {2023}, author = {Noori, HG and Tadjrobehkar, O and Moazamian, E}, title = {Biofilm stimulating activity of solanidine and Solasodine in Pseudomonas aeruginosa.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {208}, pmid = {37533040}, issn = {1471-2180}, abstract = {BACKGROUND: Biofilm formation has reported as an important virulence associated properties of Pseudomonas aeruginosa that is regulated by quorum-sensing associated genes. Biofilm and quorum-sensing interfering properties of steroidal alkaloids, Solanidine and Solasodine were investigated in the present study.

RESULTS: Biofilm formation capacity and relative expression level of five studied genes(lasI, lasR, rhlI, rhlR and algD) were significantly increased dose-dependently after treatment with sub-inhibitory concentrations (32 and 512 µg/ml) of the both Solanidine and Solasodine. Biofilm formation capacity was more stimulated in weak biofilm formers(9 iaolates) in comparison to the strong biofilm producers(11 isolates). The lasI gene was the most induced QS-associated gene among five investigated genes.

CONCLUSION: Biofilm inducing properties of the plants alkaloids and probably medicines derived from them has to be considered for revision of therapeutic guidelines. Investigating the biofilm stimulating properties of corticosteroids and other medicines that comes from plant alkaloids also strongly proposed.}, } @article {pmid37532364, year = {2023}, author = {Fan, G and Xiao, Q and Li, Q and Xia, Y and Feng, H and Ma, X and Cai, L and Sun, X}, title = {Antimicrobial mechanisms of ZnO nanoparticles to phytopathogen Pseudomonas syringae: Damage of cell envelope, suppression of metabolism, biofilm and motility, and stimulation of stomatal immunity on host plant.}, journal = {Pesticide biochemistry and physiology}, volume = {194}, number = {}, pages = {105455}, doi = {10.1016/j.pestbp.2023.105455}, pmid = {37532364}, issn = {1095-9939}, abstract = {Nanoparticles have recently been employed as a new strategy to act as bactericides in agricultural applications. However, the effects and mechanisms of foliar deposition of nanoparticles on bacterial pathogens, plant physiology and particularly plant immunity have not been sufficiently understood. Here, we investigated the effects and mechanisms of ZnO NPs in controlling of tobacco wildfire caused by Pseudomonas syringae pv. tabaci, through the comprehensive analysis of biological changes of both bacteria and plants. The global gene expression changes of Pseudomonas syringae pv. tabaci supported that the functions of "protein secretion", "membrane part", "signal transducer activity", "locomotion", "chemotaxis" and "taxis" in bacteria, as well as the metabolic pathways of "bacterial chemotaxis", "two-component system", "biofilm formation", "ABC transporters" and "valine, leucine and isoleucine degradation" were significantly down-regulated by ZnO NPs. Correspondingly, we reconfirmed that the cell envelope structure, biofilm and motility of Pseudomonas syringae pv. tabaci were directly disrupted or suppressed by ZnO NPs. Different from completely killing Pseudomonas syringae pv. tabaci, ZnO NPs (0.5 mg/mL) potentially improved plant growth and immunity through enzymatic activity and global molecular response analysis. Furthermore, the changes of gene expression in ABA signaling pathway, ABA concentration and stomatal aperture all supported that ZnO NPs can specifically stimulate stomatal immunity, which is important to defend bacterial infection. Taken together, we proposed that both the inhibition or damage of motility, biofilm, metabolisms, virulence and cell envelope on P. syringae pv. tabaci, and the activation of the stomatal immunity formed two-layered antibacterial mechanisms of ZnO NPs on phytopathogenic bacteria.}, } @article {pmid37531623, year = {2023}, author = {Cheng, J and Long, M and Zhou, C and Ilhan, ZE and Calvo, DC and Rittmann, BE}, title = {Long-Term Continuous Test of H2-Induced Denitrification Catalyzed by Palladium Nanoparticles in a Biofilm Matrix.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c01268}, pmid = {37531623}, issn = {1520-5851}, abstract = {Pd[0] catalysis and microbially catalyzed reduction of nitrate (NO3[-]-N) were combined as a strategy to increase the kinetics of NO3[-] reduction and control selectivity to N2 gas versus ammonium (NH4[+]). Two H2-based membrane biofilm reactors (MBfRs) were tested in continuous mode: one with a biofilm alone (H2-MBfR) and the other with biogenic Pd[0] nanoparticles (Pd[0]NPs) deposited in the biofilm (Pd-H2-MBfR). Solid-state characterizations of Pd[0]NPs in Pd-H2-MBfR documented that the Pd[0]NPs were uniformly located along the outer surfaces of the bacteria in the biofilm. Pd-H2-MBfR had a higher rate of NO3[-] reduction compared to H2-MBfR, especially when the influent NO3[-] concentration was high (28 mg-N/L versus 14 mg-N/L). Pd-H2-MBfR enriched denitrifiers of Dechloromonas, Azospira, Pseudomonas, and Stenotrophomonas in the microbial community and also increased abundances of genes affiliated with NO3[-]-N reductases, which reflected that the denitrifying bacteria could channel their respiratory electron flow to NO3[-] reduction to NO2[-]. N2 selectivity in Pd-H2-MBfR was regulated by the H2/NO3[-] flux ratio: 100% selectivity to N2 was achieved when the ratio was less than 1.3 e[-] equiv of H2/e[-] equiv N, while the selectivity toward NH4[+] occurred with larger H2/NO3[-] flux ratios. Thus, the results with Pd-H2-MBfR revealed two advantages of it over the H2-MBfR: faster kinetics for NO3[-] removal and controllable selectivity toward N2 versus NH4[+]. By being able to regulate the H2/NO3[-] flux ratio, Pd-H2-MBfR has significant implications for improving the efficiency and effectiveness of the NO3[-] reduction processes, ultimately leading to more environmentally benign wastewater treatment.}, } @article {pmid37531560, year = {2023}, author = {Tan, J and Yang, J and Aobulikasimu, N and Zhang, C and Cao, B and Lv, H and Jiang, M and Han, L and Huang, X}, title = {Senkyunolide B exhibits broad-spectrum antifungal activity against plant and human pathogenic fungi via inhibiting spore germination and destroying the mature biofilm.}, journal = {Pest management science}, volume = {}, number = {}, pages = {}, doi = {10.1002/ps.7696}, pmid = {37531560}, issn = {1526-4998}, abstract = {BACKGROUND: Aspergillus infection seriously jeopardize the health and safety of life of immunocompromised patients. The emergences of antifungal resistance highlight a demand to find new effective antifungal drugs. Angelica sinensis is a medicine-food herb and phthalides are its characteristic components. A few of phthalides have been reported to display satisfactory antifungal activities against plant pathogenic fungi. However, the structure activity relationships and antifungal action mechanism of phthalides remain to be further explored and elucidated.

RESULTS: The antifungal activities of five natural phthalides and four artificial analogues were investigated, and their structure activity relationships were preliminarily elucidated in current study. The benzene ring moiety played an essential role in their antifungal activities; the oxygen-containing substituents on the benzene ring obviously impact their activities, the free hydroxyl was favorable to the activity. Typical phthalide senkyunolide B (SENB) exhibited broad antifungal activities against human and plant pathogenic fungi, especially, Aspergillus fumigatus. SENB affected the spore germination and hyphae growth of A. fumigatus via downregulating phosphatidylinositol-PKC-calcineurin axis and the expression of ENG genes. Moreover, SENB disturbed the oxidation-reduction process in A. fumigatus to destroy the mature biofilms. In vivo experiments indicated SENB significantly prolonged survival and decreased fungal burden in mouse model of invasive pulmonary aspergillosis.

CONCLUSIONS: Phthalides could be considered as the valuable leads for the development of antifungal drug to cure plant and human disease. This article is protected by copyright. All rights reserved.}, } @article {pmid37529323, year = {2023}, author = {Schaedig, E and Cantrell, M and Urban, C and Zhao, X and Greene, D and Dancer, J and Gross, M and Sebesta, J and Chou, KJ and Grabowy, J and Gross, M and Kumar, K and Yu, J}, title = {Isolation of phosphorus-hyperaccumulating microalgae from revolving algal biofilm (RAB) wastewater treatment systems.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1219318}, pmid = {37529323}, issn = {1664-302X}, abstract = {Excess phosphorus (P) in wastewater effluent poses a serious threat to aquatic ecosystems and can spur harmful algal blooms. Revolving algal biofilm (RAB) systems are an emerging technology to recover P from wastewater before discharge into aquatic ecosystems. In RAB systems, a community of microalgae take up and store wastewater P as polyphosphate as they grow in a partially submerged revolving biofilm, which may then be harvested and dried for use as fertilizer in lieu of mined phosphate rock. In this work, we isolated and characterized a total of 101 microalgae strains from active RAB systems across the US Midwest, including 82 green algae, 9 diatoms, and 10 cyanobacteria. Strains were identified by microscopy and 16S/18S ribosomal DNA sequencing, cryopreserved, and screened for elevated P content (as polyphosphate). Seven isolated strains possessed at least 50% more polyphosphate by cell dry weight than a microalgae consortium from a RAB system, with the top strain accumulating nearly threefold more polyphosphate. These top P-hyperaccumulating strains include the green alga Chlamydomonas pulvinata TCF-48 g and the diatoms Eolimna minima TCF-3d and Craticula molestiformis TCF-8d, possessing 11.4, 12.7, and 14.0% polyphosphate by cell dry weight, respectively. As a preliminary test of strain application for recovering P, Chlamydomonas pulvinata TCF-48 g was reinoculated into a bench-scale RAB system containing Bold basal medium. The strain successfully recolonized the system and recovered twofold more P from the medium than a microalgae consortium from a RAB system treating municipal wastewater. These isolated P-hyperaccumulating microalgae may have broad applications in resource recovery from various waste streams, including improving P removal from wastewater.}, } @article {pmid37528258, year = {2023}, author = {Kharga, K and Dhar, I and Kashyap, S and Sengupta, S and Kumar, D and Kumar, L}, title = {Zingerone inhibits biofilm formation and enhances antibiotic efficacy against Salmonella biofilm.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {10}, pages = {268}, pmid = {37528258}, issn = {1573-0972}, abstract = {Salmonella enterica serovar Typhi is a significant cause of typhoid fever and a major public health problem. The ability of S. Typhi to form biofilms on living and non-living surfaces results in antibiotic resistance and poses a major challenge in health care. In this study, we assessed the ability of zingerone alone and in combination with antibiotics against the motility phenotypes and biofilm-forming ability of S. Typhi. Results showed that zingerone effectively reduced the swimming, swarming, and twitching phenotypes and exhibited biofilm inhibition potential. Moreover, zingerone enhanced the antibiofilm activity of ciprofloxacin and kanamycin. Microscopic analysis revealed a thinner biofilm in the presence of zingerone, which may have enhanced the antibiofilm efficacy of the antibiotics. The microscopic analysis showed that the presence of zingerone resulted in a reduction in the thickness of the biofilm, potentially increasing the antibiofilm efficacy of the antibiotics. In silico molecular docking and simulation studies further indicated that zingerone may bind to the fimbriae subunits (FimA, FimC, FimH, and FimY) of S. Typhi and form stable interactions. These findings provide important insights into the potential of zingerone to target biofilm-associated Salmonella infections. Further research is considered a promising option for designing innovative approaches to prevent infections associated with biofilms. Schematic representation of the role of zingerone in biofilm, motility inhibition and molecular interactions with biofilm associated proteins.}, } @article {pmid37526405, year = {2023}, author = {Putta, CL and Rahman, SNR and Chakraborthy, P and Shunmugaperumal, T}, title = {Development, systematic optimization and biofilm disruption activity of eugenol-based nanosized emulsions stabilized with Tween 80.}, journal = {Journal of microencapsulation}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/02652048.2023.2244094}, pmid = {37526405}, issn = {1464-5246}, abstract = {The aims of this study were to systematically optimize a formula for eugenol emulsions via face-centered central composite design and to assess the activity against two-different bacterial strains (Staphylococcus aureus and Propionibacterium acnes) present at planktonic and biofilm forms. The molecular interaction of excipients, mean particle size (MPS) including zeta potential (ZP), drug entrapment efficiency (DEE) and in vitro drug release of optimized emulsions was done using FT-IR, Malvern Zetasizer, ultracentrifugation technique and membrane-free dissolution model, respectively. The emulsions consisted of 151.3 ± 1.45 nm MPS, -21.3 ± 1.25 mV ZP and 93.98 ± 1.41% DEE values. On storage of emulsions at 25° C for 3 months, the value of DEE was found to be 72.12 ± 2.82%. The Tween 80 emulsifier film coverage onto the dispersed eugenol droplets of emulsions delayed significantly the drug release (12 to 19%) compared to the drug release occurred from pure eugenol. The treatment of planktonic S. aureus and P. acnes with diluted eugenol emulsions showed the minimum inhibitory concentration and minimum bactericidal concentration values at 1.25-2.5 mg/ml whereas it occurred at 10 mg/ml for pure eugenol. Treating the biofilms with eugenol emulsions (1-2 mg/ml) yielded 59 -70% minimum biofilm eradication concentration but 10 mg/ml pure eugenol showed 60%. Hence, the eugenol emulsions displayed antibacterial activity and could be projected as an antibiofilm or biofilm disruption agent.}, } @article {pmid37523919, year = {2023}, author = {Zhu, Q and Qian, D and Yuan, M and Li, Z and Xu, Z and Liang, S and Yu, W and Yuan, S and Yang, J and Hou, H and Hu, J}, title = {Revealing the roles of chemical communication in restoring the formation and electroactivity of electrogenic biofilm under electrical signaling disruption.}, journal = {Water research}, volume = {243}, number = {}, pages = {120421}, doi = {10.1016/j.watres.2023.120421}, pmid = {37523919}, issn = {1879-2448}, abstract = {Electrogenic biofilms in microbial electrochemical systems have played significant roles in simultaneous wastewater treatment and energy recovery owing to their unique extracellular electron transfer. Their formation has been shown to be regulated by electrical and chemical communication, but the interaction between these signal communication pathways has not been studied. This research investigated the coordination between intracellular c-di-GMP signaling and reinforced quorum sensing with or without exogenous HSL (a common quorum sensing molecule), on the formation of mixed-cultured electrogenic biofilm under electrical signaling disruption by tetraethylammonium (TEA, a broad-range potassium channel blocker). Intracellular c-di-GMP was spontaneously reinforced in response to TEA stress, and metagenomic analysis revealed that the dominant DGC (the genes for producing c-di-GMP) induced the eventual biofilm formation by mediating exopolysaccharide synthesis. Meanwhile, reinforced quorum sensing by exogenous HSL could also benefit the biofilm restoration, however, it alleviated the TEA-induced communication stress, resulting in the weakening of c-di-GMP dominance. Interestingly, suppressing electrical communication with or without HSL addition both induced selective enrichment of Geobacter of 85.5% or 30.1% respectively. Functional contribution analysis revealed the significant roles of Geobacter and Thauera in c-di-GMP signaling, especially Thauera in resistance to TEA stress. This study proposed a potential strategy for electrogenic biofilm regulation from the perspectives of cell-to-cell communication.}, } @article {pmid37525255, year = {2023}, author = {Wang, Z and Xu, W and Gao, Y and Zha, M and Zhang, D and Peng, X and Zhang, H and Wang, C and Xu, C and Zhou, T and Liu, D and Niu, H and Liu, Q and Chen, Y and Zhu, C and Guo, T and Ying, H}, title = {Engineering Saccharomyces cerevisiae for improved biofilm formation and ethanol production in continuous fermentation.}, journal = {Biotechnology for biofuels and bioproducts}, volume = {16}, number = {1}, pages = {119}, pmid = {37525255}, issn = {2731-3654}, support = {BK20202002//Natural Science Foundation of Jiangsu Province/ ; BK20190035//Natural Science Foundation of Jiangsu Province/ ; 202010//DL was supported by the Jiangsu Qinglan Talent Program/ ; 22178172//National Natural Science Foundation of China/ ; 2021YFC2101204//National Key Research and Development Program of China/ ; BE2019001//Key R&D Plan of Jiangsu Province/ ; }, abstract = {BACKGROUND: Biofilm-immobilized continuous fermentation has the potential to enhance cellular environmental tolerance, maintain cell activity and improve production efficiency.

RESULTS: In this study, different biofilm-forming genes (FLO5, FLO8 and FLO10) were integrated into the genome of S. cerevisiae for overexpression, while FLO5 and FLO10 gave the best results. The biofilm formation of the engineered strains 1308-FLO5 and 1308-FLO10 was improved by 31.3% and 58.7% compared to that of the WT strain, respectively. The counts of cells adhering onto the biofilm carrier were increased. Compared to free-cell fermentation, the average ethanol production of 1308, 1308-FLO5 and 1308-FLO10 was increased by 17.4%, 20.8% and 19.1% in the biofilm-immobilized continuous fermentation, respectively. Due to good adhering ability, the fermentation broth turbidity of 1308-FLO5 and 1308-FLO10 was decreased by 22.3% and 59.1% in the biofilm-immobilized fermentation, respectively. Subsequently, for biofilm-immobilized fermentation coupled with membrane separation, the engineered strain significantly reduced the pollution of cells onto the membrane and the membrane separation flux was increased by 36.3%.

CONCLUSIONS: In conclusion, enhanced biofilm-forming capability of S. cerevisiae could offer multiple benefits in ethanol fermentation.}, } @article {pmid37525011, year = {2023}, author = {Matar, MA and Darwish, SS and Salma, RS and Lotfy, WA}, title = {Evaluation of the antibacterial activity of Enamelast® and Fluor defender® fluoride varnishes against Streptococcus mutans biofilm: an in vitro study in primary teeth.}, journal = {European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry}, volume = {}, number = {}, pages = {}, pmid = {37525011}, issn = {1996-9805}, abstract = {PURPOSE: The aim of the current work was to compare the antibacterial activity of Enamelast® and Fluor defender® fluoride varnish on biofilm generation by Streptococcus mutans on extracted primary teeth.

METHODS: Thirty-six primary molars were collected and sliced into seventy-two test model disks. All specimens were examined, and the cracked or broken ones were discarded. A total number of specimens (n = 54) were divided into two experimental analyses viz; biofilm formation (n = 27) and microscopic examination (n = 27). Specimens of each analysis were tested under different experimental conditions: a negative control group (n = 9), Fluor defender group (n = 9), and Enamelast group (n = 9). Following treatment, biofilms were generated by adherent Streptococcus mutans on the test model disks on three time intervals: 24 h (n = 3), 48 h (n = 3), and 72 h (n = 3) for each analysis. Then, for biofilm formation analysis, the biofilm was detected spectrophotometrically at 620 nm after being stained by crystal violet. For microscopical analysis, the surfaces of the test model disks were visualized by scanning electron microscopy (SEM), and each image was processed and analyzed using ImageJ software.

RESULTS: At 48 and 72 h, Enamelast® and Fluor defender®-treated group showed significantly (p < 0.001) slight adhered bacterial cells when compared with the negative control group as revealed by the absorbance and SEM. Compared with the Fluor defender®-treated group, the absorbance of the Enamelast®-treated group showed a significant (p < 0.001) increase by approximately 7- and 16.5-fold at 48 and 72 h, respectively. Similarly, SEM showed that the number of bacterial cells adhered to enamel surfaces in the Fluor defender®-treated group was significantly (p < 0.001) fewer than the Enamelast®-treated group by approximately 36.55% and 20.62% at 48 and 72 h after exposure, respectively.

CONCLUSION: We conclude that the anti-biofilm activity of Fluor defender® against Streptococcus mutans was significantly (p < 0.001) greater than Enamelast® fluoride varnish. The use of Fluor defender® is encouraged as a preventive measure in children with the high risk of developing dental caries.}, } @article {pmid37522232, year = {2023}, author = {Ma, J and Jin, N and Wang, J and Cao, X and Zhang, M}, title = {Evaluation of deproteinised bovine bone matrix combined with absorbable biofilm for the preservation of extraction sites of mandibular impacted wisdom teeth.}, journal = {Technology and health care : official journal of the European Society for Engineering and Medicine}, volume = {}, number = {}, pages = {}, doi = {10.3233/THC-230043}, pmid = {37522232}, issn = {1878-7401}, abstract = {BACKGROUND: Bone defects and deep periodontal pockets often exist distal to the second molar after mandibular third molar extraction, seriously threatening the periodontal health of the second molar.

OBJECTIVE: To evaluate the effect of socket preservation with bone substitute materials on alveolar bone resorption and prevention of the distal periodontal defect of the adjacent tooth after mandibular impacted third molar extraction compared with natural healing.

METHODS: Ninety-nine patients with mandibular impacted teeth, treated in our hospital from January 2018 to December 2020, were randomly divided into the control and experimental groups. The experimental group underwent minimally invasive tooth extraction and socket preservation using the deproteinised bovine bone mineral, Bio-Oss and the bioabsorbable collagen membrane, Bio-Gide. The control group healed naturally after minimally invasive tooth extraction. The alveolar ridge dimension of the extraction sites, the probing depth, tooth mobility and gingival index on the distal aspect of the mandibular second molars were examined and recorded before and six months after the operations.

RESULTS: There was a significant difference between the experimental group and the control group in the alveolar bone width (P< 0.05) and height (P< 0.05) before and after surgery. The probing depth of the extraction sites in both groups was reduced.

CONCLUSION: Using Bio-Oss and Bio-Gide to preserve extraction sites of impacted teeth can promote recovery more effectively than natural healing on the height of the distal alveolar bone and the width of the alveolar crest of the second molar and thus improve the periodontal status of the adjacent second molar.}, } @article {pmid37520362, year = {2023}, author = {Das, T and Das, B and Young, BC and Aldilla, V and Sabir, S and Almohaywi, B and Willcox, M and Manefield, M and Kumar, N}, title = {Ascorbic acid modulates the structure of the Pseudomonas aeruginosa virulence factor pyocyanin and ascorbic acid-furanone-30 combination facilitate biofilm disruption.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1166607}, pmid = {37520362}, issn = {1664-302X}, abstract = {The production of pyocyanin by Pseudomonas aeruginosa increases its virulence, fitness and biofilm formation. Pyocyanin is also a redox molecule and we hypothesize that ascorbic acid being an antioxidant will interact with pyocyanin. The main objective of this study was to investigate the potential interaction of ascorbic acid with pyocyanin, and also to investigate the impact of ascorbic acid in combination with Furanone-30 on quorum sensing and biofilm formation of P. aeruginosa. When incubated with ascorbic acid, hyperchromic and hypsochromic shifts in pyocyanin absorbance peaks at 385 nm and 695 nm were observed. In the presence of dehydroascorbic acid and citric acid, these shifts were absent, indicating that the intrinsic antioxidant property of ascorbic acid was probably essential in binding to pyocyanin. NMR spectroscopy showed shifts in [1]H NMR pyocyanin peaks between 8.2 to 5.8 ppm when incubated in the presence of ascorbic acid. Density Functional Theory (DFT) supported potential interactions between the -CH2OH or -OH moieties of ascorbic acid with the -C=O moiety of pyocyanin. The pyocyanin-ascorbic acid complex impaired pyocyanin binding to DNA. Ascorbic acid combined with furanone-30 elevated quorum-sensing inhibition in P. aeruginosa, which was directly associated with significantly reduced P. aeruginosa virulence, adhesion, aggregation and biofilm formation and enhanced antibiotic-mediated bacterial killing. This study demonstrated that the antioxidant ascorbic acid directly binds to pyocyanin, modulates its structure and results in disruption of biofilm formation and associated tolerance to antibiotics.}, } @article {pmid37520908, year = {2022}, author = {Razavipour, M and Gonzalez, M and Singh, N and Cimenci, CE and Chu, N and Alarcon, EI and Villafuerte, J and Jodoin, B}, title = {Biofilm Inhibition and Antiviral Response of Cold Sprayed and Shot Peened Copper Surfaces: Effect of Surface Morphology and Microstructure.}, journal = {Journal of thermal spray technology}, volume = {31}, number = {1-2}, pages = {130-144}, pmid = {37520908}, issn = {1544-1016}, abstract = {Antibacterial properties of copper against planktonic bacteria population are affected by surface microstructure and topography. However, copper interactions with bacteria in a biofilm state are less studied. This work aims at better understanding the difference in biofilm inhibition of bulk, cold-sprayed, and shot-peened copper surfaces and gaining further insights on the underlying mechanisms using optical and scanning electron microscopy to investigate the topography and microstructure of the surfaces. The biofilm inhibition ability is reported for all surfaces. Results show that the biofilm inhibition performance of cold sprayed copper, while initially better, decreases with time and results in an almost identical performance than as-received copper after 18h incubation time. The shot-peened samples with a rough and ultrafine microstructure demonstrated an enhanced biofilm control, especially at 18 hr. The biofilm control mechanisms were explained by the diffusion rates and concentration of copper ions and the interaction between these ions and the biofilm, while surface topography plays a role in the bacteria attachment at the early planktonic state. Furthermore, the data suggest that surface topography plays a key role in antiviral activity of the materials tested, with a smooth surface being the most efficient.}, } @article {pmid37520742, year = {2022}, author = {Failor, KC and Silver, B and Yu, W and Heindl, JE}, title = {Biofilm disruption and bactericidal activity of aqueous ozone coupled with ultrasonic dental scaling.}, journal = {JADA foundational science}, volume = {1}, number = {}, pages = {100003}, pmid = {37520742}, issn = {2772-414X}, abstract = {BACKGROUND: The COVID-19 pandemic has heightened the awareness of a common hazard encountered in the dental clinic: aerosol transmission of pathogens. Treatment of sources of infection before or during dental procedures is one means of decreasing pathogen load and aerosol transmission.

METHODS: An ultrasonic scaler supplied with aqueous ozone was used to examine the effect of its viability on planktonic cultures and biofilms formed by 2 model bacteria: Rothia mucilaginosa and Escherichia coli.

RESULTS: Both organisms showed susceptibility to aqueous ozone alone (97% and 99.5% lethality, respectively). When combined with manual scaling using an ultrasonic scaler, a greater than 99% reduction in colony-forming units (CFUs)/mL could be reached with an aqueous ozone concentration of approximately 2 mg/L (R. mucilaginosa) or 0.75 mg/L (E. coli) after 5 through 6 seconds of scaling.

CONCLUSIONS: Aqueous ozone coupled with ultrasonic scaling exhibited a higher efficiency of microbial kill than either method used alone. Both gram-positive and gram-negative species were affected by this treatment. Studies on other oral microbiota constituents, including fungi and viruses, will provide information on the efficacy of this method on a greater biological scale. Studies to verify concomitant reduction of microbial load in dispersed aerosols in clinical settings should be completed to support practical applications of this treatment.}, } @article {pmid37517670, year = {2023}, author = {Lock, GA and Helfer, VE and Dias, BB and Torres, BGS and DE-Araújo, BV and Dalla-Costa, T}, title = {POPULATION PHARMACOKINETIC MODELING OF THE INFLUENCE OF CHRONIC AND ACUTE BIOFILM-FORMING Pseudomonas aeruginosa LUNG INFECTION ON CIPROFLOXACIN FREE PULMONARY AND EPITHELIAL LINING FLUID CONCENTRATIONS.}, journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences}, volume = {}, number = {}, pages = {106546}, doi = {10.1016/j.ejps.2023.106546}, pmid = {37517670}, issn = {1879-0720}, abstract = {We previously reported that ciprofloxacin (CIP) free lung interstitial concentrations are decreased by biofilm-forming Pseudomonas aeruginosa pulmonary chronic (14 d) infection. To get a better understanding on the influence of infection on CIP lung distribution, in the present study free lung interstitial fluid and epithelial lining fluid (ELF) concentrations were determined by microdialysis in biofilm-forming P. aeruginosa acutely (2 d) and chronically infected (14 d) Wistar rats following CIP 20 mg/kg i.v. bolus dosing. A popPK model was developed, using NONMEM® (version 7.4.3) with FOCE+I, with plasma data described as a three-compartment model with first-order elimination. For lung data inclusion, the model was expanded to four compartments and ELF concentrations were described as a fraction of lung levels estimated as a distribution factor (ƒD). Acute infection had a minor impact on plasma and lung CIP distribution and both infection stages did not alter ELF drug penetration. Probability of target attainment of ƒAUC0-24/MIC ≥ 90 using 20 mg q8h, equivalent to 400 mg q8h in humans, showed that CIP free concentrations in plasma are adequate to successfully treat lung infections. However, lung and ELF free interstitial concentrations might be insufficient to result in efficacious treatment of biofilm-forming P. aeruginosa chronic infection. However, lung and ELF free interstitial concentrations might be insufficient to result in efficacious treatment of biofilm-forming P. aeruginosa chronic infection.}, } @article {pmid37517664, year = {2023}, author = {Chen, Y and Yang, J and Xiao, L and Jiang, L and Wang, X and Tang, Y}, title = {Role of Nano-Fe3O4 for enhancing nitrate removal in microbial electrolytic cells: Characterizations and microbial patterns of cathodic biofilm.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139643}, doi = {10.1016/j.chemosphere.2023.139643}, pmid = {37517664}, issn = {1879-1298}, abstract = {Conductive magnetite nanoparticle (Nano-Fe3O4) can facilitate numerous biological reduction reactions as an outstanding electron mediator for electron transfer. The positive role of Nano-Fe3O4 for nitrate removal has gradually gained attention recent years, however, it has not been clarified for the persistence of the promoting effect under different concentrations addition. Performance of nitrogen removal and characteristics of cathodic biofilm were evaluated in this study after Nano-Fe3O4 addition with gradient concentration of 100∼500 mg L[-1] in microbial electrolytic cells (MEC). Our study illustrated that the optimal concentration was 200 mg L[-1] as the removal rate of nitrate increased by 24.76% and the removal rate of total dissolved nitrogen by 29.72%. At the optimal concentration, Nano-Fe3O4 increased cathodic biofilm DNA concentration by 61.04%, enhanced electron transport system activity, enriched iron redox bacteria, denitrifying bacteria and genes, as well as increased extracellular polymeric substances (EPS) amount, especially the protein content of soluble-EPS. However, promoting effect on nitrate removal was not visible in high concentration (500 mg L[-1]) addition, its electron transport system activity and EPS content were even declined. XPS results indicated that high concentration of Nano-Fe3O4 may reduce the availability of electrons to cathodic biofilm by competing for electrons, which inhibit nitrate removal.}, } @article {pmid37517233, year = {2023}, author = {Zhang, S and Li, Y and Jiang, L and Han, W and Zhao, Y and Jiang, X and Li, J and Shi, W and Zhang, X}, title = {Organic fertilizer facilitates the soil microplastic surface degradation and enriches the diversity of bacterial biofilm.}, journal = {Journal of hazardous materials}, volume = {459}, number = {}, pages = {132139}, doi = {10.1016/j.jhazmat.2023.132139}, pmid = {37517233}, issn = {1873-3336}, abstract = {The land-use of organic fertilizers is considered as an important sustainable method for resource utilization, which may have an impact on the microplastic behaviors in the soil. Here, a 240-d dark culture experiment was conducted to reveal the degradation and biofilm characteristics of degradable and refractory granule microplastics in soil and soil-fertilizer systems. The results indicated that microplastics generally exhibited a weak weight loss as well as a specific etiolation on the surface after the culture, especially polyvinyl-chloride and polyhydroxyalkanoates (PHA). Increase in carbon-oxygen functional groups and the changes of oxygen/carbon ratios were noticed, which implied that oxidation and degradation occurred on the surface of microplastics during the cultural process. The changes were more intense on the degradable PHA, and the fertilized-soil treatment than those of the refractory microplastics and the pure soil. Moreover, the addition of organic fertilizers enriched the community diversity of bacterial biofilm on multiple microplastic surfaces. In this regard, the animal fertilizers provided a stronger effect than the plant fertilizers. Overall, the soil, fertilizer and microplastic types affected the community structure and diversity of bacterial biofilm. The outcomes of this study would provide a theoretical basis for the utilization of organic matters for agricultural soil applications.}, } @article {pmid37517232, year = {2023}, author = {Zheng, Z and Huang, Y and Liu, L and Wang, L and Tang, J}, title = {Interaction between microplastic biofilm formation and antibiotics: Effect of microplastic biofilm and its driving mechanisms on antibiotic resistance gene.}, journal = {Journal of hazardous materials}, volume = {459}, number = {}, pages = {132099}, doi = {10.1016/j.jhazmat.2023.132099}, pmid = {37517232}, issn = {1873-3336}, abstract = {As two pollutants with similar transport pathways, microplastics (MPs) and antibiotics (ATs) inevitably co-exist in water environments, and their interaction has become a topic of intense research interest for scholars over the past few years. This paper comprehensively and systematically reviews the current interaction between MPs and ATs, in particular, the role played by biofilm developed MPs (microplastic biofilm). A summary of the formation process of microplastic biofilm and its unique microbial community structure is presented in the paper. The formation of microplastic biofilm can enhance the adsorption mechanisms of ATs on primary MPs. Moreover, microplastic biofilm system is a diverse and vast reservoir of genetic material, and this paper reviews the mechanisms by which microplastics with biofilm drive the production of antibiotic resistance genes (ARGs) and the processes that selectively enrich for more ARGs. Meanwhile, the enrichment of ARGs may lead to the development of microbial resistance and the gradual loss of the antimicrobial effect of ATs. The transfer pathways of ARGs affected by microplastic biofilm are outlined, and ARGs dependent transfer of antibiotic resistance bacteria (ARB) is mainly through horizontal gene transfer (HGT). Furthermore, the ecological implications of the interaction between microplastic biofilm and ATs and perspectives for future research are reviewed. This review contributes to a new insight into the aquatic ecological environmental risks and the fate of contaminants (MPs, ATs), and is of great significance for controlling the combined pollution of these two pollutants.}, } @article {pmid37516211, year = {2023}, author = {Liu, X and Jiang, Z and Liu, Z and Li, D and Liu, Z and Dong, X and Yan, S and Zhu, L and Cui, D and Chen, L and Wang, J}, title = {Biofilm-forming ability of Salmonella enterica strains of different serotypes isolated from multiple sources in China.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106275}, doi = {10.1016/j.micpath.2023.106275}, pmid = {37516211}, issn = {1096-1208}, abstract = {Salmonella is an important zoonotic and foodborne pathogen that can infect humans and animals, causing severe concerns about food safety and a heavy financial burden worldwide. The pathogen can adhere to living and abiotic surfaces by forming biofilms, which increases the risk of transmission and infection. In this study, we investigated the biofilm-forming ability of 243 Salmonella strains of 36 serotypes from different sources in China using microplate crystal violet staining method. The results showed that 99.6% tested strains, with the exception of one strain of S. Thompson, were capable of forming biofilms. The strains with the biofilm-forming ability of strong, medium and weak accounted for 2.88%, 24.28% and 72.43%, respectively. The strains of S. Havana and S. Hvittingfoss had the strongest biofilm-forming ability, with the OD570 of 0.81 ± 0.02 and 0.81 ± 0.38, respectively, while the strains of S. Agona and S. Bovismorbificans had the weakest biofilm-forming ability, with the OD570 of 0.16 ± 0.02 and 0.15 ± 0.00, respectively. Furthermore, statistical analysis results demonstrated that isolation of source had no effect on the biofilm formation ability, while the detection rates of pefABCD and ddhC were positively correlated with the biofilm formation ability of Salmonella. In particular, the detection rate of ddhC gene was more than 60% in the biofilm forming strains. These findings have important guiding significance for the investigation of pathogenesis, as well as the prevention and control of salmonellosis.}, } @article {pmid37515529, year = {2023}, author = {Lv, X and Jiang, J and Ren, J and Li, H and Yang, D and Song, X and Hu, Y and Wang, W and Dong, X}, title = {Nitric Oxide-Assisted Photodynamic Therapy for Enhanced Penetration and Hypoxic Bacterial Biofilm Elimination.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2302031}, doi = {10.1002/adhm.202302031}, pmid = {37515529}, issn = {2192-2659}, abstract = {The presence of a biofilm matrix barrier and hypoxic microenvironment within biofilm significantly impedes the efficacy of photodynamic therapy for bacterial biofilm infections. Herein, we report a phototherapeutic nanoagent with type-I photodynamic behavior and nitric oxide (NO) release performance for overcoming biofilm-associated infectious diseases. Sodium nitroprusside (SNP), a NO donor, was loaded onto amino-modified mesoporous silica nanoparticles (MSN) to form MSN@SNP NPs. The resulting nanoparticles were further modified with a porphyrin-based metal-organic framework (Ti-TCPP MOF) to obtain MSN@MOF/SNP NPs (MMS NPs) for phototherapeutic applications. In the hypoxia biofilm microenvironment, the MMS NPs release NO to enhance the biofilm permeability and induce the generation of hydroxyl radical (•OH) and superoxide anion radical (O2 [•-]) via Type-I photodynamic pathway under laser irradiation. Subsequently, the biofilm-associated infections are effectively eliminated through reactive oxygen species (ROS) and NO gas synergistic therapy. In addition, NO also stimulates collagen deposition and promotes angiogenesis in vivo. Therefore, the MMS NPs efficiently treat biofilm-related infections, providing an alternative approach to combat biofilm-associated infectious diseases. This article is protected by copyright. All rights reserved.}, } @article {pmid37515381, year = {2023}, author = {Howard, SA and Carr, CM and Sbahtu, HI and Onwukwe, U and López, MJ and Dobson, ADW and McCarthy, RR}, title = {Enrichment of native plastic-associated biofilm communities to enhance polyester degrading activity.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16466}, pmid = {37515381}, issn = {1462-2920}, support = {SBF006/1040//Academy of Medical Sciences/the Wellcome Trust/the Government Department of Business, Energy and Industrial Strategy/the British Heart Foundation/Diabetes UK Springboard Award/ ; BB/V007823/1//Biotechnology and Biological Sciences Research Council New Investigator Award/ ; 887648//European Commission/ ; NE/X010902/1//Natural Environment Research Council/ ; }, abstract = {Plastic pollution is an increasing worldwide problem urgently requiring a solution. While recycling rates are increasing globally, only 9% of all plastic waste has been recycled, and with the cost and limited downstream uses of recycled plastic, an alternative is needed. Here, we found that expanded polystyrene (EPS) promoted high levels of bacterial biofilm formation and sought out environmental EPS waste to characterize these native communities. We demonstrated that the EPS attached communities had limited plastic degrading activity. We then performed a long-term enrichment experiment where we placed a robust selection pressure on these communities by limiting carbon availability such that the waste plastic was the only carbon source. Seven of the resulting enriched bacterial communities had increased plastic degrading activity compared to the starting bacterial communities. Pseudomonas stutzeri was predominantly identified in six of the seven enriched communities as the strongest polyester degrader. Sequencing of one isolate of P. stutzeri revealed two putative polyesterases and one putative MHETase. This indicates that waste plastic-associated biofilms are a source for bacteria that have plastic-degrading potential, and that this potential can be unlocked through selective pressure and further in vitro enrichment experiments, resulting in biodegradative communities that are better than nature.}, } @article {pmid37514124, year = {2023}, author = {Kim, J and Chin, YW}, title = {Antimicrobial Agent against Methicillin-Resistant Staphylococcus aureus Biofilm Monitored Using Raman Spectroscopy.}, journal = {Pharmaceutics}, volume = {15}, number = {7}, pages = {}, doi = {10.3390/pharmaceutics15071937}, pmid = {37514124}, issn = {1999-4923}, abstract = {The prevalence of antimicrobial-resistant bacteria has become a major challenge worldwide. Methicillin-resistant Staphylococcus aureus (MRSA)-a leading cause of infections-forms biofilms on polymeric medical devices and implants, increasing their resistance to antibiotics. Antibiotic administration before biofilm formation is crucial. Raman spectroscopy was used to assess MRSA biofilm development on solid culture media from 0 to 48 h. Biofilm formation was monitored by measuring DNA/RNA-associated Raman peaks and protein/lipid-associated peaks. The search for an antimicrobial agent against MRSA biofilm revealed that Eugenol was a promising candidate as it showed significant potential for breaking down biofilm. Eugenol was applied at different times to test the optimal time for inhibiting MRSA biofilms, and the Raman spectrum showed that the first 5 h of biofilm formation was the most antibiotic-sensitive time. This study investigated the performance of Raman spectroscopy coupled with principal component analysis (PCA) to identify planktonic bacteria from biofilm conglomerates. Raman analysis, microscopic observation, and quantification of the biofilm growth curve indicated early adhesion from 5 to 10 h of the incubation time. Therefore, Raman spectroscopy can help in monitoring biofilm formation on a solid culture medium and performing rapid antibiofilm assessments with new antibiotics during the early stages of the procedure.}, } @article {pmid37514069, year = {2023}, author = {Alshehri, FA and Alharbi, MS}, title = {The Effect of Adjunctive Use of Hyaluronic Acid on Prevalence of Porphyromonas gingivalis in Subgingival Biofilm in Patients with Chronic Periodontitis: A Systematic Review.}, journal = {Pharmaceutics}, volume = {15}, number = {7}, pages = {}, doi = {10.3390/pharmaceutics15071883}, pmid = {37514069}, issn = {1999-4923}, abstract = {Porphyromonas gingivalis (P. gingivalis) is a Gram-negative anaerobic bacterium that plays an important role in the development and progression of periodontitis. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan that has previously demonstrated antibacterial potential in vitro against multiple bacterial species, including P. gingivalis. The purpose of this systematic review is to evaluate the effectiveness of HA as an adjunctive topical antibacterial agent to non-surgical mechanical therapy of periodontitis in reducing the prevalence of P. gingivalis in subgingival biofilms. Five clinical studies were identified that satisfied the eligibility criteria. Only three trials were suitable for the meta-analysis as they provided data at three and six months. Data on the prevalence of P. gingivalis in each study were collected. The odds ratio (OR) for measuring the effect size with a 95% confidence interval (CI) was applied to the available data. The results did not favor the use of HA during non-surgical mechanical therapy to reduce the prevalence of P. gingivalis in subgingival biofilm (odd ratio = 0.95 and 1.11 at three and six months, consecutively). Within their limitations, the current data do not indicate an advantage for using HA during mechanical periodontal therapy to reduce the prevalence of P. gingivalis.}, } @article {pmid37513241, year = {2023}, author = {Shi, J and Wang, Y and He, W and Ye, Z and Liu, M and Zhao, Z and Lam, JWY and Zhang, P and Kwok, RTK and Tang, BZ}, title = {Precise Molecular Engineering of Type I Photosensitizer with Aggregation-Induced Emission for Image-Guided Photodynamic Eradication of Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {14}, pages = {}, doi = {10.3390/molecules28145368}, pmid = {37513241}, issn = {1420-3049}, support = {16306620//Research Grant Council of Hong Kong/ ; 16303221//Research Grant Council of Hong Kong/ ; C6014-20W//Research Grant Council of Hong Kong/ ; ITC-CNERC14SC01//Innovation and Technology Commission/ ; MHP/047/19//Innovation and Technology Commission/ ; ZDSYS20211021111400001//Shenzhen Key Laboratory of Functional Aggregate Materials/ ; KQTD20210811090142053//Science Technology Innovation Commission of Shenzhen Municipality/ ; JCYJ20220818103007014//Science Technology Innovation Commission of Shenzhen Municipality/ ; }, abstract = {Biofilm-associated infections exert more severe and harmful attacks on human health since they can accelerate the generation and development of the antibiotic resistance of the embedded bacteria. Anti-biofilm materials and techniques that can eliminate biofilms effectively are in urgent demand. Therefore, we designed a type I photosensitizer (TTTDM) with an aggregation-induced emission (AIE) property and used F-127 to encapsulate the TTTDM into nanoparticles (F-127 AIE NPs). The NPs exhibit highly efficient ROS generation by enhancing intramolecular D-A interaction and confining molecular non-radiative transitions. Furthermore, the NPs can sufficiently penetrate the biofilm matrix and then detect and eliminate mature bacterial biofilms upon white light irradiation. This strategy holds great promise for the rapid detection and eradication of bacterial biofilms.}, } @article {pmid37513013, year = {2023}, author = {Yang, C and Song, G and Son, J and Howard, L and Yu, XY}, title = {Revealing the Bacterial Quorum-Sensing Effect on the Biofilm Formation of Diatom Cylindrotheca sp. Using Multimodal Imaging.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071841}, pmid = {37513013}, issn = {2076-2607}, support = {11025//Oak Ridge National Laboratory/ ; 41206154//China National Scholarship/ ; }, abstract = {Diatoms contribute to carbon fixation in the oceans by photosynthesis and always form biofouling organized by extracellular polymeric substances (EPS) in the marine environment. Bacteria-produced quorum-sensing signal molecules N-acyl homoserine lactones (AHLs) were found to play an important role in the development of Cylindrotheca sp. in previous studies, but the EPS composition change was unclear. This study used the technology of alcian blue staining and scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to directly observe the biofilm formation process. The results showed that AHLs promote the growth rates of diatoms and the EPS secretion of biofilm components. AHLs facilitated the diatom-biofilm formation by a forming process dependent on the length of carbon chains. AHLs increased the biofilm thickness and the fluorescence intensity and then altered the three-dimensional (3D) structures of the diatom-biofilm. In addition, the enhanced EPS content in the diatom-biofilm testified that AHLs aided biofilm formation. This study provides a collection of new experimental evidence of the interaction between bacteria and microalgae in fouling biofilms.}, } @article {pmid37512977, year = {2023}, author = {Yang, Y and Fei, N and Ji, W and Qiao, P and Yang, L and Liu, D and Guan, W and Zhao, T}, title = {pilA Gene Contributes to Virulence, Motility, Biofilm Formation, and Interspecific Competition of Bacteria in Acidovorax citrulli.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071806}, pmid = {37512977}, issn = {2076-2607}, abstract = {Acidovorax citrulli, the causative agent of bacterial fruit blotch, can be divided into two main groups based on factors such as pathogenicity and host species preference. PilA is an important structural and functional component of type IV pili (T4P). Previous studies have found significant differences in pilA DNA sequences between group I and group II strains of A. citrulli. In this study, we characterized pilA in the group I strain pslb65 and the group II strain Aac5. pilA mutants, complementation strains, and cross-complementation strains were generated, and their biological phenotypes were analyzed to identify functional differences between pilA in the two groups. pilA deletion mutants (pslb65-ΔpilA and Aac5-ΔpilA) showed significantly reduced pathogenicity compared with the wild-type (WT) strains; pslb65-ΔpilA also completely lost twitching motility, whereas Aac5-ΔpilA only partially lost motility. In King's B medium, there were no significant differences in biofilm formation between pslb65-ΔpilA and WT pslb65, but Aac5-ΔpilA showed significantly reduced biofilm formation compared to WT Aac5. In M9 minimal medium, both mutants showed significantly lower biofilm formation compared to the corresponding WT strains, although biofilm formation was recovered in the complementation strains. The biofilm formation capacity was somewhat recovered in the cross-complementation strains but remained significantly lower than in the WT strains. The interspecies competitive abilities of pslb65-ΔpilA and Aac5-ΔpilA were significantly lower than in the WT strains; Aac5-ΔpilA was more strongly competitive than pslb65-ΔpilA, and the complementation strains recovered competitiveness to WT levels. Furthermore, the cross-complementation strains showed stronger competitive abilities than the corresponding WT strains. The relative expression levels of genes related to T4P and the type VI secretion system were then assessed in the pilA mutants via quantitative PCR. The results showed significant differences in the relative expression levels of multiple genes in pslb65-ΔpilA and Aac5-ΔpilA compared to the corresponding WT stains. This indicated the presence of specific differences in pilA function between the two A. citrulli groups, but the regulatory mechanisms involved require further study.}, } @article {pmid37512934, year = {2023}, author = {Caudal, F and Rodrigues, S and Dufour, A and Artigaud, S and Le Blay, G and Petek, S and Bazire, A}, title = {Extracts from Wallis Sponges Inhibit Vibrio harveyi Biofilm Formation.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071762}, pmid = {37512934}, issn = {2076-2607}, support = {ANR-17-EURE-0015//Interdisciplinary graduate school for the blue planet/ ; //FC is the recipient of a doctoral fellowship (PhD SPOQS project) co-funded by the Université de Bretagne Sud (UBS) and the Institut de Recherche pour le Développement (IRD)/ ; //French Oceanographic Fleet, IRD, MNHN, Labex Mer and the Wallis and Futuna Environment Service/ ; }, abstract = {Pathogenic bacteria and their biofilms are involved in many human and animal diseases and are a major public health problem with, among other things, the development of antibiotic resistance. These biofilms are known to induce chronic infections for which classical treatments using antibiotic therapy are often ineffective. Sponges are sessile filter-feeding marine organisms known for their dynamic symbiotic partnerships with diverse microorganisms and their production of numerous metabolites of interest. In this study, we investigated the antibiofilm efficacy of different extracts from sponges, isolated in Wallis, without biocidal activity. Out of the 47 tested extracts, from 28 different genera, 11 showed a strong activity against Vibrio harveyi biofilm formation. Moreover, one of these extracts also inhibited two quorum-sensing pathways of V. harveyi.}, } @article {pmid37512929, year = {2023}, author = {Kim, B and Gurung, S and Han, SR and Lee, JH and Oh, TJ}, title = {Comparative Genomic Analysis of Biofilm-Forming Polar Microbacterium sp. Strains PAMC22086 and PAMC21962 Isolated from Extreme Habitats.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071757}, pmid = {37512929}, issn = {2076-2607}, support = {PM22030//Korea Polar Research Institute/ ; }, abstract = {The members of Microbacterium isolated from different environments are known to form peptidoglycan. In this study, we compared the biofilm-forming abilities of Microbacterium sp. PAMC22086 (PAMC22086), which was isolated from the soil in the South Shetland Islands and Microbacterium sp. PAMC21962 (PAMC21962), which was isolated from algae in the South Shetland Islands. The analysis of average nucleotide identity and phylogeny of PAMC22086 revealed a 97% similarity to Microbacterium oxydans VIU2A, while PAMC21962 showed a 99.1% similarity to Microbacterium hominis SGAir0570. For the comparative genomic analysis of PAMC22086 and PAMC21962, the genes related to biofilm formation were identified using EggNOG and KEGG pathway databases. The genes possessed by both PAMC22086 and PAMC21962 are cpdA, phnB, rhlC, and glgC, which regulate virulence, biofilm formation, and multicellular structure. Among the genes indirectly involved in biofilm formation, unlike PAMC21962, PAMC22086 possessed csrA, glgC, and glgB, which are responsible for attachment and glycogen biosynthesis. Additionally, in PAMC22086, additional functional genes rsmA, which is involved in mobility and polysaccharide production, and dksA, GTPase, and oxyR, which play roles in cell cycle and stress response, were identified. In addition, the biofilm-forming ability of the two isolates was examined in vivo using the standard crystal violet staining technique, and morphological differences in the biofilm were investigated. It is evident from the different distribution of biofilm-associated genes between the two strains that the bacteria can survive in different niches by employing distinct strategies. Both strains exhibit distinct morphologies. PAMC22086 forms a biofilm that attaches to the side, while PAMC21962 indicates growth starting from the center. The biofilm formation-related genes in Microbacterium are not well understood. However, it has been observed that Microbacterium species form biofilm regardless of the number of genes they possess. Through comparison between different Microbacterium species, it was revealed that specific core genes are involved in cell adhesion, which plays a crucial role in biofilm formation. This study provides a comprehensive profile of the Microbacterium genus's genomic features and a preliminary understanding of biofilm in this genus, laying the foundation for further research.}, } @article {pmid37512916, year = {2023}, author = {Amemiya, K and Rozak, DA and Dankmeyer, JL and Dorman, WR and Marchand, C and Fetterer, DP and Worsham, PL and Purcell, BK}, title = {Shiga-Toxin-Producing Strains of Escherichia coli O104:H4 and a Strain of O157:H7, Which Can Cause Human Hemolytic Uremic Syndrome, Differ in Biofilm Formation in the Presence of CO2 and in Their Ability to Grow in a Novel Cell Culture Medium.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071744}, pmid = {37512916}, issn = {2076-2607}, support = {1.1A0018_07_RD-B//JSTOR/ ; }, abstract = {One pathogen that commonly causes gastrointestinal illnesses from the consumption of contaminated food is Escherichia coli O157:H7. In 2011 in Germany, however, there was a prominent outbreak of bloody diarrhea with a high incidence of hemolytic uremic syndrome (HUS) caused by an atypical, more virulent E. coli O104:H4 strain. To facilitate the identification of this lesser-known, atypical E. coli O104:H4 strain, we wanted to identify phenotypic differences between it and a strain of O157:H7 in different media and culture conditions. We found that E. coli O104:H4 strains produced considerably more biofilm than the strain of O157:H7 at 37 °C (p = 0.0470-0.0182) Biofilm production was significantly enhanced by the presence of 5% CO2 (p = 0.0348-0.0320). In our study on the innate immune response to the E. coli strains, we used HEK293 cells that express Toll-like receptors (TLRs) 2 or 4. We found that E. coli O104:H4 strains had the ability to grow in a novel HEK293 cell culture medium, while the E. coli O157:H7 strain could not. Thus, we uncovered previously unknown phenotypic properties of E. coli O104:H4 to further differentiate this pathogen from E. coli O157:H7.}, } @article {pmid37512829, year = {2023}, author = {Fu, T and Fan, Z and Li, Y and Li, Z and Zhao, H and Feng, Y and Xue, G and Cui, J and Yan, C and Gan, L and Feng, J and Yuan, J and You, F}, title = {Roles of the Crp/Fnr Family Regulator ArcR in the Hemolysis and Biofilm of Staphylococcus aureus.}, journal = {Microorganisms}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/microorganisms11071656}, pmid = {37512829}, issn = {2076-2607}, abstract = {Staphylococcus aureus is an opportunistic human pathogen that is often involved in severe infections such as pneumonia and sepsis in which bacterial virulence factors play a key role. Infections caused by S. aureus are often difficult to eradicate, particularly when they are associated with biofilm. The physiological roles of the Crp/Fnr family regulator ArcR are elusive in S. aureus. In this study, it was found that the deletion of arcR increased the hemolytic ability and biofilm formation in S. aureus. Differential gene expression analysis by RNA-seq and real-time quantitative reverse transcription PCR showed that genes associated with hemolytic ability (hla and hlb) and biofilm formation (icaA, icaB, icaC and icaD) were significantly upregulated compared with those in the wild-type strain. The results revealed that ArcR regulated the expression of the hla and ica operon by binding to their promoter regions, respectively. This study provided new insights into the functional importance of ArcR in regulating the virulence and biofilm of S. aureus.}, } @article {pmid37511440, year = {2023}, author = {Li, P and Yin, R and Cheng, J and Lin, J}, title = {Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention.}, journal = {International journal of molecular sciences}, volume = {24}, number = {14}, pages = {}, doi = {10.3390/ijms241411680}, pmid = {37511440}, issn = {1422-0067}, support = {32070103, 31700031//National Natural Science Foundation of China/ ; 2023KXJ-019//Qinchuang Yuan "Scientist + Engineer" Team Construction Project of Shaanxi Province/ ; 2020//Regional Development Talent Project of the "Special Support Plan" of Shaanxi Province/ ; 2018//Outstanding Young Talent Support Plan of the Higher Education Institutions of Shaanxi Province/ ; 2022//Youth Innovation Team of Shaanxi Universities/ ; }, abstract = {Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as venous ducts, joint prostheses, mechanical heart valves, and catheters. Biofilms provide a protective barrier for bacteria and provide resistance to antimicrobial agents, which increases the morbidity and mortality of patients. This review summarizes biofilm formation processes and resistance mechanisms, as well as the main features of clinically persistent infections caused by biofilms. Considering the various infections caused by clinical medical devices, we introduce two main methods to prevent and treat biomaterial-related biofilm infection: antibacterial coatings and the surface modification of biomaterials. Antibacterial coatings depend on the covalent immobilization of antimicrobial agents on the coating surface and drug release to prevent and combat infection, while the surface modification of biomaterials affects the adhesion behavior of cells on the surfaces of implants and the subsequent biofilm formation process by altering the physical and chemical properties of the implant material surface. The advantages of each strategy in terms of their antibacterial effect, biocompatibility, limitations, and application prospects are analyzed, providing ideas and research directions for the development of novel biofilm infection strategies related to therapeutic materials.}, } @article {pmid37511337, year = {2023}, author = {Șchiopu, P and Toc, DA and Colosi, IA and Costache, C and Ruospo, G and Berar, G and Gălbău, ȘG and Ghilea, AC and Botan, A and Pană, AG and Neculicioiu, VS and Todea, DA}, title = {An Overview of the Factors Involved in Biofilm Production by the Enterococcus Genus.}, journal = {International journal of molecular sciences}, volume = {24}, number = {14}, pages = {}, doi = {10.3390/ijms241411577}, pmid = {37511337}, issn = {1422-0067}, abstract = {Enterococcus species are known for their ability to form biofilms, which contributes to their survival in extreme environments and involvement in persistent bacterial infections, especially in the case of multi-drug-resistant strains. This review aims to provide a comprehensive understanding of the mechanisms underlying biofilm formation in clinically important species such as Enterococcus faecalis and the less studied but increasingly multi-drug-resistant Enterococcus faecium, and explores potential strategies for their eradication. Biofilm formation in Enterococcus involves a complex interplay of genes and virulence factors, including gelatinase, cytolysin, Secreted antigen A, pili, microbial surface components that recognize adhesive matrix molecules (MSCRAMMs), and DNA release. Quorum sensing, a process of intercellular communication, mediated by peptide pheromones such as Cob, Ccf, and Cpd, plays a crucial role in coordinating biofilm development by targeting gene expression and regulation. Additionally, the regulation of extracellular DNA (eDNA) release has emerged as a fundamental component in biofilm formation. In E. faecalis, the autolysin N-acetylglucosaminidase and proteases such as gelatinase and serin protease are key players in this process, influencing biofilm development and virulence. Targeting eDNA may offer a promising avenue for intervention in biofilm-producing E. faecalis infections. Overall, gaining insights into the intricate mechanisms of biofilm formation in Enterococcus may provide directions for anti-biofilm therapeutic research, with the purpose of reducing the burden of Enterococcus-associated infections.}, } @article {pmid37511256, year = {2023}, author = {Jeyachandran, S and Chellapandian, H and Park, K and Kwak, IS}, title = {Exploring the Antimicrobial Potential and Biofilm Inhibitory Properties of Hemocyanin from Hemifusus pugilinus (Born, 1778).}, journal = {International journal of molecular sciences}, volume = {24}, number = {14}, pages = {}, doi = {10.3390/ijms241411494}, pmid = {37511256}, issn = {1422-0067}, support = {NRF-2018-R1A6A1A-03024314//National Research Foundation of Korea/ ; }, abstract = {The seafood industry plays a huge role in the blue economy, exploiting the advantage of the enriched protein content of marine organisms such as shrimps and molluscs, which are cultured in aquafarms. Diseases greatly affect these aquatic organisms in culture and, hence, there is need to study, in detail, their innate immune mechanisms. Hemocyanin is a non-specific innate defense molecule present in the blood cells of several invertebrates, especially molluscs, arthropods, and annelids. It is concerned with oxygen transport, blood clotting, and immune enhancement. In the present study, this macromolecular metalloprotein was isolated from the hemolymph of the marine snail Hemifusus pugilinus (Born, 1778) using Sephadex G-100 gel filtration column chromatography. It occurred as a single band (MW 80 kDa) on SDS-PAGE. High-performance liquid chromatography (HPLC) of the purified hemocyanin showed a single peak with a retention time of 4.3 min. The secondary structure and stability of the protein were detected using circular dichroism (CD), and the spectra demonstrated negative ellipticity bands close to 208 nm and 225 nm, indicating β-sheets. Further exploration of the purified hemocyanin revealed remarkable antimicrobial and antibiofilm activities against Gram-positive (Enterococcus faecalis and Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa and Proteus vulgaris) at a concentration of 1-5 μg/mL. Spectrophotometric and in situ microscopic analyses (CLSM) unveiled the potential of the purified hemocyanin to inhibit biofilm formation in these bacteria with a minimal inhibitory concentration of 40 μg/mL. Furthermore, H. pugilinus hemocyanin (10 μg/mL concentration) displayed antifungal activity against Aspergillus niger. The purified hemocyanin was also assessed for cytotoxicity against human cancer cells using cell viability assays. Altogether, the present study shows that molluscan hemocyanin is a potential antimicrobial, antibiofilm, antifungal, anticancer, and immunomodulatory agent, with great scope for application in the enhancement of the immune system of molluscs, thereby facilitating their aquaculture.}, } @article {pmid37509879, year = {2023}, author = {Jaroni, D and Litt, PK and Bule, P and Rumbaugh, K}, title = {Effectiveness of Bacteriophages against Biofilm-Forming Shiga-Toxigenic Escherichia coli In Vitro and on Food-Contact Surfaces.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {14}, pages = {}, doi = {10.3390/foods12142787}, pmid = {37509879}, issn = {2304-8158}, abstract = {(1) Background: Formation of biofilms on food-contact surfaces by Shiga-toxigenic Escherichia coli (STEC) can pose a significant challenge to the food industry, making conventional control methods insufficient. Targeted use of bacteriophages to disrupt these biofilms could reduce this problem. Previously isolated and characterized bacteriophages (n = 52) were evaluated against STEC biofilms in vitro and on food-contact surfaces. (2) Methods: Phage treatments (9 logs PFU/mL) in phosphate-buffered saline were used individually or as cocktails. Biofilms of STEC (O157, O26, O45, O103, O111, O121, and O145) were formed in 96-well micro-titer plates (7 logs CFU/mL; 24 h) or on stainless steel (SS) and high-density polyethylene (HDPE) coupons (9 logs CFU/cm[2]; 7 h), followed by phage treatment. Biofilm disruption was measured in vitro at 0, 3, and 6 h as a change in optical density (A595). Coupons were treated with STEC serotype-specific phage-cocktails or a 21-phage cocktail (3 phages/serotype) for 0, 3, 6, and 16 h, and surviving STEC populations were enumerated. (3) Results: Of the 52 phages, 77% showed STEC biofilm disruption in vitro. Serotype-specific phage treatments reduced pathogen population within the biofilms by 1.9-4.1 and 2.3-5.6 logs CFU/cm[2], while the 21-phage cocktail reduced it by 4.0 and 4.8 logs CFU/cm[2] on SS and HDPE, respectively. (4) Conclusions: Bacteriophages can be used to reduce STEC and their biofilms.}, } @article {pmid37509743, year = {2023}, author = {Dai, J and Huang, J and Wu, S and Zhang, F and Li, Y and Rong, D and Zhao, M and Ye, Q and Gu, Q and Zhang, Y and Wei, X and Zhang, J and Wu, Q}, title = {Occurrence, Antibiotic Susceptibility, Biofilm Formation and Molecular Characterization of Staphylococcus aureus Isolated from Raw Shrimp in China.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {14}, pages = {}, doi = {10.3390/foods12142651}, pmid = {37509743}, issn = {2304-8158}, support = {2022B1111040002//Research and Development Program of Guangdong Province/ ; 2022A1515010059//National Natural Science Foundation of Guangdong Province/ ; SKXRC202306//Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology/ ; }, abstract = {The aim of this study was to determine the prevalence and characterization of Staphylococcus aureus isolated from 145 shrimp samples from 39 cities in China. The results show that 41 samples (28%) from 24 cities were positive, and most of the positive samples (39/41, 95.1%) were less than 110 MPN/g. Antimicrobial susceptibility testing showed that only seven isolates were susceptible to all 24 antibiotics, whereas 65.1% were multidrug-resistant. Antibiotic resistance genes that confer resistance to β-lactams, aminoglycosides, tetracycline, macrolides, lincosamides and streptogramin B (MLSB), trimethoprim, fosfomycin and streptothricin antibiotics were detected. All S. aureus isolates had the ability to produce biofilm and harbored most of the biofilm-related genes. Genes encoding one or more of the important virulence factors staphylococcal enterotoxins (sea, seb and sec), toxic shock syndrome toxin 1 (tsst-1) and Panton-Valentine leukocidin (PVL) were detected in 47.6% (30/63) of the S. aureus isolates. Molecular typing showed that ST15-t085 (27.0%, 17/63), ST1-t127 (14.3%, 9/63) and ST188-t189 (11.1%, 7/63) were the dominant genetic types. The finding of this study provides the first comprehensive surveillance on the incidence of S. aureus in raw shrimp in China. Some retained genotypes found in this food have been linked to human infections around the world.}, } @article {pmid37509490, year = {2023}, author = {Rostami, G and Afrasiabi, S and Benedicenti, S and Signore, A and Chiniforush, N}, title = {The Evaluation of SWEEPS Plus Antimicrobial Photodynamic Therapy with Indocyanine Green in Eliminating Enterococcus faecalis Biofilm from Infected Root Canals: An In Vitro Study.}, journal = {Biomedicines}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/biomedicines11071850}, pmid = {37509490}, issn = {2227-9059}, abstract = {OBJECTIVES: This study aimed to assess the efficacy of shockwave-enhanced emission photoacoustic streaming (SWEEPS) plus antimicrobial photodynamic therapy (aPDT) using indocyanine green (ICG) for the elimination of Enterococcus faecalis biofilm from infected root canals.

MATERIALS AND METHODS: thirty sound human single-canal teeth were chosen and standardized to have 12 mm of root length. The root canals were shaped and prepared by means of ProTaper rotary files. After sterilization of the teeth, the canals were inoculated with E. faecalis for 2 weeks. The teeth were then randomly divided into six groups (n = five) of control, ICG, ICG + 808 nm diode laser, ICG + SWEEPS, ICG + 808 nm diode laser + SWEEPS, and 5.25% sodium hypochlorite (NaOCl). Following treatment, the number of colony-forming units (CFUs)/mL were calculated for each group. Statistical analysis was carried out using one-way ANOVA. For multiple comparisons, Tukey's test was used as the post hoc test.

RESULTS: NaOCl alone showed the highest efficacy (p < 0.001). The ICG + 808 nm diode laser + SWEEPS group displayed significantly lower amounts of bacteria than either the ICG + 808 nm diode laser or SWEEPS (p < 0.001). There was a statistically significant difference detected between the ICG + 808 nm diode laser and ICG + SWEEPS (p = 0.035).

CONCLUSIONS: SWEEPS can effectively increase the photosensitizer distribution in the root canal space, and its application along with irrigants can bring about promising results.}, } @article {pmid37508290, year = {2023}, author = {Xu, L and Kijkla, P and Kumseranee, S and Punpruk, S and Gu, T}, title = {Electrochemical Assessment of Mitigation of Desulfovibrio ferrophilus IS5 Corrosion against N80 Carbon Steel and 26Cr3Mo Steel Using a Green Biocide Enhanced by a Nature-Mimicking Biofilm-Dispersing Peptide.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071194}, pmid = {37508290}, issn = {2079-6382}, support = {00000000000//Petrobras/ ; 00000000000//PTT Public Company Limited (Thailand)/ ; }, abstract = {MIC (microbiologically influenced corrosion) is problematic in many industries, especially in the oil and gas industry. In this work, N80 carbon steel for pipelines was tested with 26Cr3Mo chromium pipeline steel for comparison in SRB (sulfate-reducing bacterium) MIC mitigation using a THPS (tetrakis hydroxymethyl phosphonium sulfate)-based commercial biocide (Biotreat 5475 with 75-80% THPS by mass). Peptide A, a nature-mimicking synthetic cyclic peptide (cys-ser-val-pro-tyr-asp-tyr-asn-trp-tyr-ser-asn-trp-cys) with biofilm dispersal ability was used as a biocide enhancer. Metal coupons covered with 3-d old Desulfovibrio ferrophilus IS5 biofilms were immersed in different biocide solutions. After 1-h treatment, 200 ppm Biotreat 5475, 200 ppm Biotreat 5475 + 200 nM (360 ppb) Peptide A, and 400 ppm Biotreat 5475 achieved 0.5-log, 1.7-log and 1.9-log reductions in sessile cell count on N80, and 0.7-log, 1.7-log, and 1.8-log on 26Cr3Mo, respectively. The addition of 200 nM Peptide A cut the THPS biocide dosage by nearly half. Biocide injection tests in electrochemical glass cells after 1 h exhibited 15%, 70%, and 72% corrosion inhibition efficiency (based on corrosion current density) on N80, and 27%, 79%, 75% on 26Cr3Mo, respectively. Linear polarization resistance and electrochemical impedance spectrometry results also indicated antimicrobial efficacies.}, } @article {pmid37508285, year = {2023}, author = {Osland, AM and Oastler, C and Konrat, K and Nesse, LL and Brook, E and Richter, AM and Gosling, RJ and Arvand, M and Vestby, LK}, title = {Evaluation of Disinfectant Efficacy against Biofilm-Residing Wild-Type Salmonella from the Porcine Industry.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071189}, pmid = {37508285}, issn = {2079-6382}, support = {3302213//Norwegian Veterinary Institute/ ; CR2006//Department for Environment, Food, and Rural Affairs (Defra)/ ; 773830: One Health European Joint Programme//European Union's Horizon 2020 search and Innovation Programme/ ; }, abstract = {Salmonella enterica is a causative pathogen of Salmonellosis, a zoonosis causing global disease and financial losses every year. Pigs may be carriers of Salmonella and contribute to the spread to humans and food products. Salmonella may persist as biofilms. Biofilms are bacterial aggregates embedded in a self-produced matrix and are known to withstand disinfectants. We studied the effect of glutaraldehyde and peracetic acid, two active substances frequently used in disinfectant formulations in the pig industry, on representative biofilm-residing wild-type Salmonella collected from pig housings in the United Kingdom (UK). We screened biofilm production of strains using the microtiter plate (MTP) assay and Congo Red Coomassie Blue (CRCB) agar method. Previously published stainless-steel coupon (SSCA), polyvinylchloride coupon (PCA), and glass bead (GBA) assays were used for disinfection studies. The mean reduction in the tested wild-type strains met the criterion of ≥4 log10 CFU at a disinfectant concentration of 0.05% with SSCA and GBA, and 0.005% with PCA for peracetic acid, along with 0.5% for glutaraldehyde with all three assays on the mean. At these concentrations, both tested disinfectants are suitable for disinfection of pig housings against Salmonella. When evaluating the efficacy of disinfectants, biofilms should be included, as higher disinfectant concentrations are necessary compared to planktonic bacteria.}, } @article {pmid37508283, year = {2023}, author = {Petkova, T and Rusenova, N and Danova, S and Milanova, A}, title = {Effect of N-Acetyl-L-cysteine on Activity of Doxycycline against Biofilm-Forming Bacterial Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071187}, pmid = {37508283}, issn = {2079-6382}, abstract = {Biofilm-forming bacteria are associated with difficult-to-cure bacterial infections in veterinary patients. According to previous studies, N-acetyl-L-cysteine (NAC) showed an inhibitory effect on biofilm formation when it was applied in combination with beta-lactam antibiotics and fluoroquinolones. The lack of information about the effect of NAC on doxycycline activity against biofilm-forming strains was the reason for conducting this study. Staphylococcus aureus (S. aureus) ATCC 25923, Staphylococcus aureus O74, Escherichia coli (E. coli) ATCC 25922 and Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853 were used to evaluate the activity of doxycycline with and without addition of NAC on planktonic bacteria and on biofilm formation. The minimum inhibitory concentrations (MICs) of doxycycline were not affected by NAC for Gram-negative strains and were found to be two times higher for the strains of S. aureus. The minimum biofilm inhibitory concentrations (MBICs) for Gram-negative bacteria (2 μg/mL for E. coli ATCC 25922 and 32 μg/mL for P. aeruginosa ATCC 27853), determined using a standard safranin colorimetric assay, were higher than the MICs (0.5 and 4 μg/mL, respectively). The data suggest that the combinations of doxycycline and NAC could stimulate the growth of planktonic cells of S. aureus and biofilm-forming E. coli ATCC 25922. NAC did not affect the strong inhibitory effect of doxycycline on the biofilm formation by the strains of S. aureus.}, } @article {pmid37508250, year = {2023}, author = {Liu, S and Liu, B and Zhu, Y and Qiu, Y and Li, B}, title = {The Spatial-Temporal Effects of Bacterial Growth Substrates on Antibiotic Resistance Gene Spread in the Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071154}, pmid = {37508250}, issn = {2079-6382}, support = {2020YFC19092-05, 2022YFC32031-04//Ministry of Science and Technology/ ; FRF-TP-20-011A3//Fundamental Research Funds for the Central Universities/ ; }, abstract = {Biofilm is considered as the hotspot of antibiotic resistance gene (ARG) dissemination. Bacterial growth substrates are important factors for biofilm formation, but its spatial-temporal effects on ARG spread in biofilm is still unclear. In this study, microfluidics combined with microscopic observation were used to reveal spatial-temporal effects of bacterial growth substrates on ARG transfer at real time. The initial horizontal gene transfer events were found to be independent of substrate levels. However, subsequent transfer processes varied greatly depending on the availability of growth substrates. The proportion of transconjugants was much higher (~12%) when observed in substrate-rich regions (under the channel) at 24 h, followed by an exponential decline, with the distance far from the channel. Furthermore, three-dimensional observation revealed that vertical gene transfer influenced by the concentrations of bacterial growth substrates was important for ARG spread in biofilm. The transfer frequency was 8.2 times higher in the high substrate concentration (50×) compared to low concentration (0.5×) in simulated sewage, underscoring the substantial impact of bacterial growth substrate variability on ARG dissemination. This study is helpful for in-depth understanding of ARG dissemination through biofilms and indicates that reducing pollutant emission is important for ARG control in the environment.}, } @article {pmid37508219, year = {2023}, author = {Ng, WJ and Hing, CL and Loo, CB and Hoh, EK and Loke, IL and Ee, KY}, title = {Ginger-Enriched Honey Attenuates Antibiotic Resistant Pseudomonas aeruginosa Quorum Sensing Virulence Factors and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071123}, pmid = {37508219}, issn = {2079-6382}, abstract = {Quorum sensing (QS) in Pseudomonas aeruginosa plays an essential role in virulence factors, biofilm formation as well as antibiotic resistance. Approaches that target virulence factors are known to be more sustainable than antibiotics in weakening the infectivity of bacteria. Although honey has been shown to exert antipseudomonal activities, the enhancement of such activity in ginger-enriched honey is still unknown. The main objective of this study was to determine the impacts of honey and ginger-enriched honey on the QS virulence factors and biofilm formation of antibiotic resistant P. aeruginosa clinical isolates. Outcomes showed honey and/or ginger-enriched honey significantly reduced the protease activity, pyocyanin production and exotoxin A concentration of the isolates. The swarming and swimming motility together with biofilm formation in all clinical isolates were also significantly inhibited by both honey samples. Notable morphological alteration of bacterial cells was also observed using scanning electron microscopy. A principal component analysis (PCA) managed to distinguish the untreated group and treatment groups into two distinct clusters, although honey and ginger-enriched honey groups were not well differentiated. This study revealed the effectiveness of honey including ginger-enriched honey to attenuate QS virulence factors and biofilm formation of P. aeruginosa.}, } @article {pmid37508193, year = {2023}, author = {Salaie, RN and Hassan, PA and Meran, ZD and Hamad, SA}, title = {Antibacterial Activity of Dissolved Silver Fractions Released from Silver-Coated Titanium Dental Implant Abutments: A Study on Streptococcus mutans Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, doi = {10.3390/antibiotics12071097}, pmid = {37508193}, issn = {2079-6382}, abstract = {(1) Background: The aim of this research was to investigate the antibacterial activity of dissolved silver from silver-coated titanium implants against Streptococcus mutans. (2) Methodology: Silver-coated titanium implant discs were immersed in 1.8 mL of brain heart infusion broth (BHIB) and incubated for 24 h in order to release the silver ions into the broth. The coating quality was confirmed via EDS, and the dissolved silver was measured via inductively coupled plasma mass spectrometry (ICP-MS). The experimental design used unconditioned broth (control) and broth conditioned with silver released from silver-coated titanium implants (n = 6). Regarding the antibacterial activity, isolated Streptococcus mutans was used. A turbidity test and lactate production test were performed to determine the effect of dissolved silver on bacterial growth in a suspension and biofilm formation. (3) Result: The results showed that the coating was successfully applied on the substrate. There was around 0.3 mg/L of silver released into the BHIB, and the turbidity of the control group was significantly higher than the treatment, with measured absorbance values of 1.4 and 0.8, respectively, indicating that the dissolved silver ions from the silver-coated titanium discs exhibited some degree of antibacterial activity by preventing the growth of Streptococcus mutans. However, the results of the antibiofilm activity test did not show any significant difference between the groups. (4) Conclusion: The dissolved silver from silver-coated titanium implants has an antibacterial activity but not a significant antimicrobial activity, indicating that the dissolved silver from silver-coated titanium abutments can significantly reduce the incidence of peri-implant mucositis.}, } @article {pmid37508046, year = {2023}, author = {Ferdous, FB and Islam, MS and Ullah, MA and Rana, ML and Punom, SA and Neloy, FH and Chowdhury, MNU and Hassan, J and Siddique, MP and Saha, S and Rahman, MT}, title = {Antimicrobial Resistance Profiles, Virulence Determinants, and Biofilm Formation in Enterococci Isolated from Rhesus Macaques (Macaca mulatta): A Potential Threat for Wildlife in Bangladesh?.}, journal = {Animals : an open access journal from MDPI}, volume = {13}, number = {14}, pages = {}, doi = {10.3390/ani13142268}, pmid = {37508046}, issn = {2076-2615}, support = {2022/12/BAU//Bangladesh Agricultural University Research System/ ; }, abstract = {Enterococci are commensal bacteria that inhabit the digestive tracts of animals and humans. The transmission of antibiotic-resistant genes through human-animal contact poses a potential public health risk worldwide, as zoonoses from wildlife reservoirs can occur on every continent. The purpose of this study was to detect Enterococcus spp. in rhesus macaques (Macaca mulatta) and to investigate their resistance patterns, virulence profiles, and biofilm-forming ability. Conventional screening of rectal swabs (n = 67) from macaques was followed by polymerase chain reaction (PCR). The biofilm-forming enterococci were determined using the Congo red agar plate assay. Using the disk diffusion test (DDT), antibiogram profiles were determined, followed by resistance and virulence genes identification by PCR. PCR for bacterial species confirmation revealed that 65.7% (44/67) and 22.4% (15/67) of the samples tested positive for E. faecalis and E. faecium, respectively. All the isolated enterococci were biofilm formers. In the DDT, enterococcal isolates exhibited high to moderate resistance to penicillin, rifampin, ampicillin, erythromycin, vancomycin, and linezolid. In the PCR assays, the resistance gene blaTEM was detected in 61.4% (27/44) of E. faecalis and 60% (9/15) of E. faecium isolates. Interestingly, 88.63 % (39/44) of E. faecalis and 100% (15/15) of E. faecium isolates were phenotypically multidrug-resistant. Virulence genes (agg, fsrA, fsrB, fsrC, gelE, sprE, pil, and ace) were more frequent in E. faecalis compared to E. faecium; however, isolates of both Enterococcus spp. were found negative for the cyl gene. As far as we know, the present study has detected, for the first time in Bangladesh, the presence of virulence genes in MDR biofilm-forming enterococci isolated from rhesus macaques. The findings of this study suggest employing epidemiological surveillance along with the one-health approach to monitor these pathogens in wild animals in Bangladesh, which will aid in preventing their potential transmission to humans.}, } @article {pmid37506947, year = {2023}, author = {Shao, S and Sheng, M and Ye, Y and Wang, C and Pan, D and Wu, X}, title = {New perspective on effect of β-cyclodextrin on nitrification-denitrification and denitrification phosphorus removal in biogenic manganese oxides driven moving bed biofilm reactor: Performance evaluation, microbial community and process.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129502}, doi = {10.1016/j.biortech.2023.129502}, pmid = {37506947}, issn = {1873-2976}, abstract = {Effect of β-cyclodextrin (β-CD) on simultaneous removal of NH4[+]-N, NO3[-]-N, COD, and phosphorus (P) in biogenic manganese oxides (BioMnOx) driven moving bed biofilm reactor (MBBR) was investigated. 58.64% and 86.32%, 79.65% and 98.39%, 62.45% and 97.30%, and 24.80% and 95.90% of TN and COD were removed in phases I-IV, indicating that simultaneous nitrification and denitrification (SND) efficiencies were 75.44%, 83.91%, 72.71%, and 35.83%, respectively. Composition and fluorescence spectral characteristics of extracellular polymeric substance (EPS) were evaluated including the removal kinetics of TN and COD. Metabolic activity of Mn[2+], decolorization performance of BioMnOx, and reactive oxygen species (ROS) characteristics were determined in biofilm. Furthermore, intermediate Mn[3+] and BioMnOx concentration were analyzed. Finally, the removal process of nitrogen (N) and P was proposed based on characterizations of elemental characterization, electrochemistry, and microbial community. This study provides new insights into the N and P removal mediated by BioMnOx and β-CD.}, } @article {pmid37506547, year = {2023}, author = {Mendonça, CMN and Oliveira, RC and Pizauro, LJL and Pereira, WA and Abboud, K and Almeida, S and Watanabe, IS and Varani, AM and Domínguez, JM and Correa, B and Venema, K and Azevedo, POS and Oliveira, RPS}, title = {Tracking new insights into antifungal and anti-mycotoxigenic properties of a biofilm forming Pediococcus pentosaceus strain isolated from grain silage.}, journal = {International journal of food microbiology}, volume = {405}, number = {}, pages = {110337}, doi = {10.1016/j.ijfoodmicro.2023.110337}, pmid = {37506547}, issn = {1879-3460}, abstract = {The present study offers detailed insights into the antifungal and anti-mycotoxigenic potential of a biofilm forming lactic acid bacterium (Pediococcus pentosaceus) against one atoxigenic (Aspergillus flavus) and two toxigenic (Aspergillus nomius and Fusarium verticillioides) fungal strains. The antifungal effect of P. pentosaceus LBM18 strain was initially investigated through comparative analysis of fungi physiology by macroscopic visual evaluations and scanning electron microscopy examinations. The effects over fungal growth rate and asexual sporulation were additionally accessed. Furthermore, analytical evaluations of mycotoxin production were carried out by HPLC-MS/MS to provide insights on the bacterial anti-mycotoxigenic activity over fungal production of the aflatoxins B1, B2, G1 and G2 as well as fumonisins B1 and B2. Finally, reverse transcription quantitative real-time PCR (RT-qPCR) analysis was employed at the most effective bacterial inoculant concentration to evaluate, at the molecular level, the down-regulation of genes aflR, aflQ and aflD, related to the biosynthesis of aflatoxins by the strain of Aspergillus nomius. The effects over mycotoxin contamination were thought to be result of a combination of several biotic and abiotic factors, such as interaction between living beings and physical-chemical aspects of the environment, respectively. Several possible mechanisms of action were addressed along with potentially deleterious effects ascribing from P. pentosaceus misuse as biopesticide, emphasizing the importance of evaluating lactic acid bacteria safety in new applications, concentrations, and exposure scenarios.}, } @article {pmid37506546, year = {2023}, author = {Liu, J and Meng, Y and Yang, MH and Zhang, XY and Zhao, JF and Sun, PH and Chen, WM}, title = {Design, synthesis and biological evaluation of novel 3-hydroxypyridin-4(1H)-ones based hybrids as Pseudomonas aeruginosa biofilm inhibitors.}, journal = {European journal of medicinal chemistry}, volume = {259}, number = {}, pages = {115665}, doi = {10.1016/j.ejmech.2023.115665}, pmid = {37506546}, issn = {1768-3254}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative pathogenic bacterium, often causative drug-resistance related human infections, given its great capacity to form bioflm. It uses three major quorum sensing (QS) systems, las, rhl, and pqs, to regulate the expression of genes related to virulence and biofilm formation. Consequently, strategies for inhibiting QS have garnered considerable attention as antimicrobial therapies. In this study, we designed and synthesized several 3-hydroxypyridin-4(1H)-one hybrids and assessed their potential as the inhibitors of P. aeruginosa biofilm formation. The most active compound identified was 12h; it exhibited satisfactory biofilm inhibitory activity (IC50: 10.59 ± 1.17 μM). Mechanistic studies revealed that 12h significantly inhibited the fluorescence of the PAO1-lasB-gfp and PAO1-pqsA-gfp fluorescent reporter strains and the production of Las-regulated (elastase) and Pqs-regulated (pyocyanin) virulence factors. These findings indicate that 12h inhibited biofilm formation by suppressing the expression of lasB and pqsA, thereby inactivating the las and pqs pathways. Furthermore, 12h improved the antibiotic susceptibility of P. aeruginosa and reduced the acute virulence of this bacterium in the African green monkey kidney cell line Vero. In conclusion, 3-hydroxypyridin-4(1H)-one hybrids, such as 12h, represent a promising class of antibacterial agents against P. aeruginosa.}, } @article {pmid37505307, year = {2023}, author = {Li, BL and Chen, JY and Hu, JJ and Fan, YW and Ao, ZY and Zhang, WJ and Lian, X and Liang, HJ and Li, QR and Guan, XX and Wu, JW and Yuan, J and Jiang, DX}, title = {Three stilbenes from pigeon pea with promising anti-methicillin-resistant Staphylococcus aureus biofilm formation activity.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37505307}, issn = {1618-1905}, abstract = {Cajaninstilbene acid (CSA), longistylin A (LLA), and longistylin C (LLC) are three characteristic stilbenes isolated from pigeon pea. The objective of this study was to evaluate the antibacterial activity of these stilbenes against Staphylococcus aureus and even methicillin-resistant Staphylococcus aureus (MRSA) and test the possibility of inhibiting biofilm formation. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these stilbenes were evaluated. And the results showed that LLA was most effective against tested strains with MIC and MBC values of 1.56 μg/mL followed by LLC with MIC and MBC values of 3.12 μg/mL and 6.25 μg/mL as well as CSA with MIC and MBC values of 6.25 μg/mL and 6.25-12.5 μg/mL. Through growth curve and cytotoxicity analysis, the concentrations of these stilbenes were determined to be set at their respective 1/4 MIC in the follow-up research. In an anti-biofilm formation assay, these stilbenes were found to be effectively inhibited bacterial proliferation, biofilm formation, and key gene expressions related to the adhesion and virulence of MRSA. It is the first time that the anti-S. aureus and MRSA activities of the three stilbenes have been systematically reported. Conclusively, these findings provide insight into the anti-MRSA mechanism of stilbenes from pigeon pea, indicating these compounds may be used as antimicrobial agents or additives for food with health functions, and contribute to the development as well as application of pigeon pea in food science.}, } @article {pmid37504760, year = {2023}, author = {Huang, J and Lei, J and Ge, A and Xiao, W and Xin, C and Song, Z and Zhang, J}, title = {Antifungal Effect of Vitamin D3 against Cryptococcus neoformans Coincides with Reduced Biofilm Formation, Compromised Cell Wall Integrity, and Increased Generation of Reactive Oxygen Species.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, doi = {10.3390/jof9070772}, pmid = {37504760}, issn = {2309-608X}, abstract = {Cryptococcus neoformans is an invasive fungus that causes both acute and chronic infections, especially in immunocompromised patients. Owing to the increase in the prevalence of drug-resistant pathogenic fungi and the limitations of current treatment strategies, drug repositioning has become a feasible strategy to accelerate the development of new drugs. In this study, the minimum inhibitory concentration of vitamin D3 (VD3) against C. neoformans was found to be 0.4 mg/mL by broth microdilution assay. The antifungal activities of VD3 were further verified by solid dilution assays and "time-kill" curves. The results showed that VD3 reduced fungal cell adhesion and hydrophobicity and inhibited biofilm formation at various developmental stages, as confirmed by crystal violet staining and the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Fluorescence staining of cellular components and a stress susceptibility assay indicated that VD3 compromised cell integrity. Reverse transcription quantitative PCR demonstrated that VD3 treatment upregulated the expression of fungal genes related to cell wall synthesis (i.e., CDA3, CHS3, FKS1, and AGS1). Moreover, VD3 enhanced cell membrane permeability and caused the accumulation of intracellular reactive oxygen species. Finally, VD3 significantly reduced the tissue fungal burden and prolonged the survival of Galleria mellonella larvae infected with C. neoformans. These results showed that VD3 could exert significant antifungal activities both in vitro and in vivo, demonstrating its potential application in the treatment of cryptococcal infections.}, } @article {pmid37504715, year = {2023}, author = {Zeng, H and Stadler, M and Abraham, WR and Müsken, M and Schrey, H}, title = {Inhibitory Effects of the Fungal Pigment Rubiginosin C on Hyphal and Biofilm Formation in Candida albicans and Candida auris.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, doi = {10.3390/jof9070726}, pmid = {37504715}, issn = {2309-608X}, support = {MWK no. 21-78904-63-5/19//Drug Discovery and Cheminformatics for New Anti-Infectives (iCA), Ministry for Science & Culture of the German State of Lower Saxony/ ; }, abstract = {The two fungal human pathogens, Candida auris and Candida albicans, possess a variety of virulence mechanisms. Among them are the formation of biofilms to protect yeast against harsh conditions through the development of (pseudo)hyphae whilst also facilitating the invasion of host tissues. In recent years, increased rates of antifungal resistance have been associated with C. albicans and C. auris, posing a significant challenge for the effective treatment of fungal infections. In the course of our ongoing search for novel anti-infectives, six selected azaphilones were tested for their cytotoxicity and antimicrobial effects as well as for their inhibitory activity against biofilm and hyphal formation. This study revealed that rubiginosin C, derived from stromata of the ascomycete Hypoxylon rubiginosum, effectively inhibited the formation of biofilms, pseudohyphae, and hyphae in both C. auris and C. albicans without lethal effects. Crystal violet staining assays were utilized to assess the inhibition of biofilm formation, while complementary microscopic techniques, such as confocal laser scanning microscopy, scanning electron microscopy, and optical microscopy, were used to investigate the underlying mechanisms. Rubiginosin C is one of the few substances known to effectively target both biofilm formation and the yeast-to-hyphae transition of C. albicans and C. auris within a concentration range not affecting host cells, making it a promising candidate for therapeutic intervention in the future.}, } @article {pmid37504685, year = {2023}, author = {Costa, PS and Basso, ME and Negri, M and Svidzinski, TIE}, title = {In Vitro and Ex Vivo Biofilm-Forming Ability of Rhinocladiella similis and Trichophyton rubrum Isolated from a Mixed Onychomycosis Case.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, doi = {10.3390/jof9070696}, pmid = {37504685}, issn = {2309-608X}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Infections caused by biofilm-forming agents have important implications for world health. Mixed infections, caused by more than one etiological agent, are also an emerging problem, especially regarding the standardization of effective diagnosis and treatment methods. Cases of mixed onychomycosis (OM) have been reported; however, studies on the microbial interactions between the different fungi in biofilms formed on nails are still scarce. We describe a case of mixed OM caused by the dermatophyte Trichophyton rubrum and the black yeast-like fungus Rhinocladiella similis. Identical growths of both fungi were observed in more than 50 cultures from different nail samples. Additionally, both species were able to form organized single and mixed biofilms, reinforcing the participation of both fungi in the etiology of this OM case. R. similis seemed to grow faster during the process, suggesting that T. rubrum benefits from biofilm development when in combination. Moreover, the biofilm of the Rhinocladiella isolate exhibited exacerbated production of the extracellular matrix, which was not observed with that of a Rhinocladiella reference strain, suggesting that the isolate had natural abilities that were possibly perfected during development in the nail of the patient.}, } @article {pmid37504433, year = {2023}, author = {Zhang, Q and Liu, Y and Ding, M and Yuwen, L and Wang, L}, title = {On-Demand Free Radical Release by Laser Irradiation for Photothermal-Thermodynamic Biofilm Inactivation and Tooth Whitening.}, journal = {Gels (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, doi = {10.3390/gels9070554}, pmid = {37504433}, issn = {2310-2861}, support = {GZR2022010004//Project of State Key Laboratory of Organic Electronics and Information Displays of Nanjing University of Posts and Telecommunications/ ; JKLB202204//Open Research Fund of Jiangsu Key Laboratory for Biosensors/ ; }, abstract = {Dental diseases associated with biofilm infections and tooth staining affect billions of people worldwide. In this study, we combine photothermal agents (MoS2@BSA nanosheets, MB NSs), a thermolysis free-radical initiator (AIPH), and carbomer gel to develop laser-responsive hydrogel (MBA-CB Gel) for biofilm inactivating and tooth whitening. Under a physiological temperature without laser irradiation, MB NSs can eliminate free radicals generated from the slow decomposition of AIPH due to their antioxidative activity, thereby avoiding potential side effects. A cytotoxicity study indicates that MB NSs can protect mammalian cells from the free radicals released from AIPH without laser irradiation. Upon exposure to laser irradiation, MB NSs promote the rapid decomposition of AIPH to release free radicals by photothermal effect, suggesting their on-demand release ability of free radicals. In vitro experimental results show that the bacteria inactivation efficiency is 99.91% (3.01 log units) for planktonic Streptococcus mutans (S. mutans) and 99.98% (3.83 log units) for planktonic methicillin-resistant Staphylococcus aureus (MRSA) by the mixed solution of MB NSs and AIPH (MBA solution) under 808 nm laser irradiation (1.0 W/cm[2], 5 min). For S. mutans biofilms, an MBA solution can inactivate 99.97% (3.63 log units) of the bacteria under similar laser irradiation conditions. Moreover, MBA-CB Gel can whiten an indigo carmine-stained tooth under laser irradiation after 60 min of laser treatment, and the color difference (ΔE) in the teeth of the MBA-CB Gel treatment group was 10.9 times that of the control group. This study demonstrates the potential of MBA-CB Gel as a promising platform for biofilm inactivation and tooth whitening. It is worth noting that, since this study only used stained models of extracted teeth, the research results may not fully reflect the actual clinic situation. Future clinical research needs to further validate these findings.}, } @article {pmid37504238, year = {2023}, author = {D'Elia, G and Floris, W and Marini, L and Corridore, D and Rojas, MA and Ottolenghi, L and Pilloni, A}, title = {Methods for Evaluating the Effectiveness of Home Oral Hygiene Measures-A Narrative Review of Dental Biofilm Indices.}, journal = {Dentistry journal}, volume = {11}, number = {7}, pages = {}, doi = {10.3390/dj11070172}, pmid = {37504238}, issn = {2304-6767}, abstract = {Dental plaque is a biofilm structured in an extracellular matrix of polymers of host and microbial origin; the microorganisms can coexist in harmony with the host, thus guarantying oral health. Environmental modifications can lead to dysbiosis and onset of oral diseases; in fact, plaque is the etiological agent both of periodontal disease and dental decay. The use of an effective oral hygiene index should be considered as a relevant goal for the clinicians and the researchers, and consequently, numerous plaque indices have been proposed during the years. The present literature review aims primarily to obtain a complete summary of these scores to assess plaque deposits. It is useful because the clinician/researcher will select the right scoring method for the specific situation only if he knows the available options and if he is aware of both their strengths and weaknesses. This review applies a basic classification of plaque indices that distinguishes the ones that use non-quantitative methods from the ones that use quantitative methods. Non-quantitative methods are more subjective because they are based on the ability of the clinician to point out the presence or the entity of deposits, while quantitative methods introduce objectifiable means to measure plaque deposits.}, } @article {pmid37503306, year = {2023}, author = {Youngblom, MA and Smith, TM and Pepperell, CS}, title = {Adaptation of the Mycobacterium tuberculosis transcriptome to biofilm growth.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.07.18.549484}, pmid = {37503306}, abstract = {UNLABELLED: Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), is a leading global cause of death from infectious disease. Biofilms are increasingly recognized as a relevant growth form during M. tb infection and may impede treatment by enabling bacterial drug and immune tolerance. M. tb has a complicated regulatory network that has been well-characterized for many relevant disease states, including dormancy and hypoxia. However, despite its importance, our knowledge of the genes and pathways involved in biofilm formation is limited. Here we characterize the biofilm transcriptomes of fully virulent clinical isolates and find that the regulatory systems underlying biofilm growth vary widely between strains and are also distinct from regulatory programs associated with other environmental cues. We used experimental evolution to investigate changes to the transcriptome during adaptation to biofilm growth and found that the application of a uniform selection pressure resulted in loss of strain-to-strain variation in gene expression, resulting in a more uniform biofilm transcriptome. The adaptive trajectories of transcriptomes were shaped by the genetic background of the M. tb population leading to convergence on a sub-lineage specific transcriptome. We identified widespread upregulation of non-coding RNA (ncRNA) as a common feature of the biofilm transcriptome and hypothesize that ncRNA function in genome-wide modulation of gene expression, thereby facilitating rapid regulatory responses to new environments. These results reveal a new facet of the M. tb regulatory system and provide valuable insight into how M. tb adapts to new environments.

IMPORTANCE: Understanding mechanisms of resistance and tolerance in Mycobacterium tuberculosis (M. tb) can help us develop new treatments that capitalize on M. tb 's vulnerabilities. Here we used transcriptomics to study both the regulation of biofilm formation in clinical isolates as well as how those regulatory systems adapt to new environments. We find that closely related clinical populations have diverse strategies for growth under biofilm conditions, and that genetic background plays a large role in determining the trajectory of evolution. These results have implications for future treatment strategies that may be informed by our knowledge of the evolutionary constraints on strain(s) from an individual infection. This work provides new information about the mechanisms of biofilm formation in M. tb and outlines a framework for population level approaches for studying bacterial adaptation.}, } @article {pmid37499434, year = {2023}, author = {Silva, E and Teixeira, JA and Pereira, MO and Rocha, CMR and Sousa, AM}, title = {Evolving biofilm inhibition and eradication in clinical settings through plant-based antibiofilm agents.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {119}, number = {}, pages = {154973}, doi = {10.1016/j.phymed.2023.154973}, pmid = {37499434}, issn = {1618-095X}, abstract = {BACKGROUND: After almost 100 years since evidence of biofilm mode of growth and decades of intensive investigation about their formation, regulatory pathways and mechanisms of antimicrobial tolerance, nowadays there are still no therapeutic solutions to eradicate bacterial biofilms and their biomedical related issues.

PURPOSE: This review intends to provide a comprehensive summary of the recent and most relevant published studies on plant-based products, or their isolated compounds with antibiofilm activity mechanisms of action or identified molecular targets against bacterial biofilms. The objective is to offer a new perspective of most recent data for clinical researchers aiming to prevent or eliminate biofilm-associated infections caused by bacterial pathogens.

METHODS: The search was performed considering original research articles published on PubMed, Web of Science and Scopus from 2015 to April 2023, using keywords such as "antibiofilm", "antivirulence", "phytochemicals" and "plant extracts".

RESULTS: Over 180 articles were considered for this review with a focus on the priority human pathogens listed by World Health Organization, including Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Inhibition and detachment or dismantling of biofilms formed by these pathogens were found using plant-based extract/products or derivative compounds. Although combination of plant-based products and antibiotics were recorded and discussed, this topic is currently poorly explored and only for a reduced number of bacterial species.

CONCLUSIONS: This review clearly demonstrates that plant-based products or derivative compounds may be a promising therapeutic strategy to eliminate bacterial biofilms and their associated infections. After thoroughly reviewing the vast amount of research carried out over years, it was concluded that plant-based products are mostly able to prevent biofilm formation through inhibition of quorum sensing signals, but also to disrupt mature biofilms developed by multidrug resistant bacteria targeting the biofilm extracellular polymeric substance. Flavonoids and phenolic compounds seemed the most effective against bacterial biofilms.}, } @article {pmid37499272, year = {2023}, author = {Dorick, JM and Macarisin, D and Dunn, L and Dev Kumar, G}, title = {Effect of aquaponic water and substratum material on biofilm formation by Aeromonas hydrophila.}, journal = {International journal of food microbiology}, volume = {404}, number = {}, pages = {110316}, doi = {10.1016/j.ijfoodmicro.2023.110316}, pmid = {37499272}, issn = {1879-3460}, abstract = {Aeromonas hydrophila is a zoonotic pathogen causing illness in fish and susceptible humans. This emerging pathogen has been isolated within aquaponic systems and could cause disease in fish and a hazard to humans consuming aquaponic produce. This study determined whether A. hydrophila from an aquaponic farm could form biofilms in aquaponic water and on materials used in these systems. A. hydrophila biofilm biomass and cell density in aquaponic water were evaluated by crystal violet staining and culture-based enumeration. Biofilm biomass and biofilm cell density were affected by the water source and A. hydrophila isolate (P < 0.05). A. hydrophila formed the most biomass from the beginning of deep-water culture (BDWC) water (OD570 0.202 ± 0.066) and the least from the end of deep-water culture (EDWC) water (OD570 0.140 ± 0.036; P < 0.05). Enumerated A. hydrophila from the biofilm varied among water sources; the fish tank water supported the greatest cell density (7.04 ± 0.71 log CFU/mL) while the EDWC supported the lowest cell density (6.76 ± 0.83 log CFU/mL). Biofilm formation was also evaluated on aquaponic materials such as nylon, polyvinyl chloride, polyethylene liner, bead filter, and foam. Biofilm formation on the liner had the greatest population (2.39 ± 0.022 log CFU/cm[2]), and the bead had the least (0.64 ± 0.039 log CFU/cm[2]; P < 0.05). Pathogenic organisms, such as A. hydrophila, may pose a greater risk to produce harvested from the BDWC and MDWC due to greater biofilm formation.}, } @article {pmid37498555, year = {2023}, author = {Fu, J and Nisbett, LM and Guo, Y and Boon, EM}, title = {NosP Detection of Heme Modulates Burkholderia thailandensis Biofilm Formation.}, journal = {Biochemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.biochem.3c00187}, pmid = {37498555}, issn = {1520-4995}, abstract = {Aggregated bacteria embedded within self-secreted extracellular polymeric substances, or biofilms, are resistant to antibiotics and cause chronic infections. As such, they are a significant public health threat. Heme is an abundant iron source for pathogenic bacteria during infection; many bacteria have systems to detect heme assimilated from host cells, which is correlated with the transition between acute and chronic infection states. Here, we investigate the heme-sensing function of a newly discovered multifactorial sensory hemoprotein called NosP and its role in biofilm regulation in the soil-dwelling bacterium Burkholderia thailandensis, the close surrogate of Bio-Safety-Level-3 pathogen Burkholderia pseudomallei. The NosP family protein has previously been shown to exhibit both nitric oxide (NO)- and heme-sensing functions and to regulate biofilms through NosP-associated histidine kinases and two-component systems. Our in vitro studies suggest that BtNosP exhibits heme-binding kinetics and thermodynamics consistent with a labile heme-responsive protein and that the holo-form of BtNosP acts as an inhibitor of its associated histidine kinase BtNahK. Furthermore, our in vivo studies suggest that increasing the concentration of extracellular heme decreases B. thailandensis biofilm formation, and deletion of nosP and nahK abolishes this phenotype, consistent with a model that BtNosP detects heme and exerts an inhibitory effect on BtNahK to decrease the biofilm.}, } @article {pmid37497045, year = {2023}, author = {}, title = {Corrigendum to "Molecular evaluation of aminoglycosides resistance and biofilm formation inKlebsiella pneumoniaeclinical isolates: A cross-sectional study".}, journal = {Health science reports}, volume = {6}, number = {7}, pages = {e1439}, doi = {10.1002/hsr2.1439}, pmid = {37497045}, issn = {2398-8835}, abstract = {[This corrects the article DOI: 10.1002/hsr2.1266.].}, } @article {pmid37496232, year = {2023}, author = {de Oliveira, MA and Barros, AB and de Araújo, GS and de Araújo, AR and Soares, MJDS and de Oliveira, DF and Lima, FCDA and Batagin-Neto, A and de Souza de Almeida Leite, JR and de Freitas Cesário, HPS and Pessoa, ODL and Marinho Filho, JDB and Araújo, AJ}, title = {Natural cordiaquinones as strategies to inhibit the growth and biofilm formation of methicillin-sensitive and -resistant Staphylococcus spp.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad162}, pmid = {37496232}, issn = {1365-2672}, abstract = {AIMS: The aim of this study was to investigate the antibacterial and antibiofilm potential of cordiaquinones B, E, L, N, and O against different Staphylococci strains, in addition to analyzing in silico the observed effect.

METHODS AND RESULTS: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined according to CLSI guidelines. The inhibition of biofilm formation was investigated at sub-MICs. Atomic force microscopy (AFM) and density functional theory method were performed. The tested strains of Staphylococcus spp. were susceptible to cordiaquinones B, E, and L, among which cordiaquinone B exerted a bactericidal effect, confirmed by a bacterial growth curve study, against Staphylococcus saprophyticus. Cordiaquinones B and E showed lowest MBC values against S. saprophyticus. AFM revealed that cordiaquinone L reduced the mean cell size of S. saprophyticus. Cordiaquinones B and E inhibited the biofilm formation ability of S. aureus by approximately 90%. The in silico analysis suggested that the antimicrobial activity of cordiaquinones is driven by their electron donation capability.

CONCLUSIONS: Cordiaquinones inhibit the growth and biofilm formation (virulence factor) of both methicillin-sensitive and -resistant staphylococci strains, indicating their antimicrobial potential.}, } @article {pmid37496193, year = {2023}, author = {Verran, J and Redfern, J and Cunliffe, A and Romachney, A and Wood, J}, title = {Hands on Biofilm! utilising a public audience in a citizen science project to assess yield variability when culturing kombucha pellicle.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnad073}, pmid = {37496193}, issn = {1574-6968}, abstract = {The pellicle biofilm generated during the Kombucha tea fermentation process has, when dried, textile-like properties that may have real-life applications. However, pellicle yield can vary depending on inoculation and incubation conditions, which affects research investigations on the properties of the pellicle. To generate data on variability to help define optimum pellicle growth conditions, as part of a public engagement event about biofilm, a citizen science activity was hosted whereby visitors to a science festival were invited to select incubation conditions and inoculate different media with liquid or solid (pellicle). More than 220 samples were inoculated (in excess of 1200 visitors mainly in family groups). The most popular incubation conditions were coconut water or tea medium, 30°C/room temperature and liquid inoculum. The most productive/reproducible in terms of yield and variability were tea medium, 30°C and liquid inoculum, which reflect some of the conditions most used in the domestic setting for kombucha culture. The event provided both useful research data and generated public interest in a research area of which many will have been unaware. Interest in the results of the activity, available several weeks after the activity, was sustained using email contact and FlickR for dissemination of images and data.}, } @article {pmid37494793, year = {2023}, author = {Wang, H and Xu, K and Wang, J and Feng, C and Chen, Y and Shi, J and Ding, Y and Deng, C and Liu, X}, title = {Microplastic biofilm: An important microniche that may accelerate the spread of antibiotic resistance genes via natural transformation.}, journal = {Journal of hazardous materials}, volume = {459}, number = {}, pages = {132085}, doi = {10.1016/j.jhazmat.2023.132085}, pmid = {37494793}, issn = {1873-3336}, abstract = {Microplastic (MP) biofilms provide a specific microniche for microbial life and are a potential hotspot for the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). Nevertheless, the acquisition of ARGs in MP biofilms via natural transformation mediated by extracellular DNA (eDNA) has been rarely explored. This study demonstrated that MP biofilms promoted the natural transformation of extracellular ARGs at the single-cell and multi-species levels, compared to natural substrate (NS) biofilms and bacterioplankton. The transformation frequency on MP biofilms was up to 1000-fold compare to that on NS. The small MPs and aged MPs enhanced the ARG transformation frequencies up to 77.16-fold and 32.05-fold, respectively, compared with the large MPs and pristine MPs. The transformation frequencies on MP biofilms were significantly positively correlated with the bacterial density and extracellular polymeric substance (EPS) content (P < 0.05). Furthermore, MPs significantly increased the expression of the biofilm formation related genes (motA and pgaA) and DNA uptake related genes (pilX and comA) compared to NS and bacterioplankton. The more transformants colonized on MPs contributed to the enhanced transformation frequencies at the community-wide level. Overall, eDNA-mediated transformation in MP biofilms may be an important path of ARG spread, which was promoted by heterogeneous biofilm.}, } @article {pmid37493941, year = {2023}, author = {Guzmán-Rodríguez, JJ and Gutiérrez-Chávez, AJ and Meléndez-Soto, RM and Amador-Sánchez, MA and Franco-Robles, E}, title = {Antimicrobial activities of Agave fructans against multi-resistant and biofilm-producing Staphylococcus aureus isolated from bovine mastitis.}, journal = {Veterinary research communications}, volume = {}, number = {}, pages = {}, pmid = {37493941}, issn = {1573-7446}, abstract = {Bovine mastitis is an emerging disease that causes large economic losses. Staphylococcus aureus its main etiological agent, is multi-resistant to antimicrobials and produces biofilm. The objective of this study was to investigate the effect of Agave fructans (AF), a type of prebiotic, on multi-resistant and biofilm-forming isolates of S. aureus. Ten isolates of S. aureus from bovine subclinical mastitis previously characterized as highly resistant to antimicrobials and biofilm formers were used in this study. The growth kinetics of S. aureus in the presence of AF was evaluated by the Baranyi and Roberts microbial growth model using the DMFit program. The antibacterial activity of AF against S. aureus was studied by the well-diffusion method and the effect on biofilm formation by the crystal violet method. All assays were performed in triplicate for each isolate and an ANOVA with Tukey's post hoc was performed considering p < 0.05 as significant. The AF showed a decrease in maximum growth rate (µmax) and OD max levels (Ymax) in all isolates with all concentrations. Also, zones of inhibition were observed due to the effect of all AF concentrations in all isolates in a dose-dependent manner. Interestingly, S. aureus biofilm formation was inhibited by all AF concentrations assessed in this study. More investigations are required to elucidate the mechanisms of action of AF on S. aureus as well as in vivo studies to evaluate its therapeutic efficacy for bovine mastitis.}, } @article {pmid37493818, year = {2023}, author = {McLeod, D and Wei, L and Li, Z}, title = {A standard 96-well based high throughput microfluidic perfusion biofilm reactor for in situ optical analysis.}, journal = {Biomedical microdevices}, volume = {25}, number = {3}, pages = {26}, pmid = {37493818}, issn = {1572-8781}, support = {R01HL144157/NH/NIH HHS/United States ; R01HL144157/NH/NIH HHS/United States ; R01HL144157/NH/NIH HHS/United States ; }, abstract = {Biofilm infections represent a major public health threat due to their high tolerance to antimicrobials and the lack of specific anti-biofilm drugs. To develop such drugs, it is crucial to have high-throughput biofilm growth systems that can emulate in vivo conditions without the cost and complexity of animal models. However, no current biofilm reactor can provide in vivo-like conditions in a high throughput standard microtiter format. This paper demonstrates a novel high-throughput (HT) microfluidic perfusion biofilm reactor (HT-μPBR) compatible with a standard 96-well microtiter plate for in situ optical analysis. A snap-on liquid-tight cover for standard microtiter plates was designed and fabricated with fluidic channels to provide closed-loop recirculating perfusion. Our system takes steps toward providing in vivo-like conditions with controlled shear stress and nutrient delivery. We describe the system fabrication and usage in optical analysis of biomass and viability of Escherichia coli (E. coli) biofilms. The HT-μPBR was set to perfuse at 1 mL/min corresponding to an average shear rate of approximately [Formula: see text] on the bottom surface of a single well. Biofilms were detected on well plate bottoms and measured using a fluorescence microscope and plate reader to determine biomass and viability. Samples cultured in the HT-μPBR showed increased biomass while maintaining viability after 24 h. The HT-μPBR can further be combined with HT antibiotic susceptibility testing and additional optical techniques such as time-lapse imaging to improve understanding of the drug reaction mechanism as well as the optimization of drug combinations and delivery profiles.}, } @article {pmid37493762, year = {2023}, author = {Mandalari, G and Minuti, A and La Camera, E and Barreca, D and Romeo, O and Nostro, A}, title = {Antimicrobial Susceptibility of Staphylococcus aureus Strains and Effect of Phloretin on Biofilm Formation.}, journal = {Current microbiology}, volume = {80}, number = {9}, pages = {303}, pmid = {37493762}, issn = {1432-0991}, abstract = {Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are known to be responsible of various infections, including biofilm-associated diseases. The aim of this study was to analyze 19 strains of S. aureus from orthopedic sites in terms of phenotypic antimicrobial susceptibility against 13 selected antibiotics, slime/biofilm formation, molecular analysis of specific antibiotic resistance genes (mecA, cfr, rpoB), and biofilm-associated genes (icaADBC operon). Furthermore, the effect of phloretin on the production of biofilm was evaluated on 8 chosen isolates. The susceptibility test confirmed almost all strains were resistant to cefoxitin and oxacillin. Most strains possess the mecA, whereas none of the strains had the cfr gene. Four strains (1, 7, 10, and 24) presented single-nucleotide polymorphisms (SNPs) in rpoB, which confer rifampicin resistance. IcaD was detected in all tested strains, whereas icaR was only found in two strains (24 and 30). Phloretin had a dose-dependent effect on biofilm production. Specifically, 0.5 × MIC determined biofilm inhibition in 5 out of 8 strains (8, 24, 25, 27, 30), whereas an increase in biofilm production was detected with phloretin at the 0.125 × MIC across all tested strains. These data are useful to potentially develop novel compounds against antibiotic-resistant S. aureus.}, } @article {pmid37491288, year = {2023}, author = {Zore, G and Abdulghani, M and Kazi, R and Shelar, A and Patil, R}, title = {Proteomic dataset of Candida albicans (ATCC 10231) Biofilm.}, journal = {BMC research notes}, volume = {16}, number = {1}, pages = {155}, pmid = {37491288}, issn = {1756-0500}, abstract = {OBJECTIVES: The ability to form biofilm is considered as one of major virulence factors of Candida albicans, as biofilms form growth confers antifungal resistance and facilitate immune evasion. It is intriguing to understand morphophysiological modulations in the C. albicans cells growing under biofilm form growth.

DATA DESCRIPTION: In present study, we have profiled biofilm-specific proteins using LC-MS/MS analysis. Whole cell proteins of C. albicans cells grown under biofilm form growth (test) and planktonic (control) growth for 24 h were extracted, digested and identified using micro-Liquid Chromatography-Mass Spectrometry (LC-MS/MS). The present data represents proteomic profile (SWATH Spectral Libraries) of C. albicans biofilm intended to be useful to scientific community as it exhibits reuse potential.}, } @article {pmid37490958, year = {2023}, author = {Tsai, YC and Lee, YP and Lin, NT and Yang, HH and Teh, SH and Lin, LC}, title = {Therapeutic effect and anti-biofilm ability assessment of a novel phage, phiPA1-3, against carbapenem-resistant Pseudomonas aeruginosa.}, journal = {Virus research}, volume = {}, number = {}, pages = {199178}, doi = {10.1016/j.virusres.2023.199178}, pmid = {37490958}, issn = {1872-7492}, abstract = {Multiple drug-resistant (MDR) Pseudomonas aeruginosa commonly causes severe hospital-acquired infections. The gradual emergence of carbapenem-resistant P. aeruginosa has recently gained attention. A wide array of P. aeruginosa-mediated pathogenic mechanisms, including its biofilm-forming ability, limits the use of effective antimicrobial treatments against it. In the present study, we isolated and characterized the phenotypic, biological, and genomic characteristics of a bacteriophage, vB_PaP_phiPA1-3 (phiPA1-3). Biofilm eradication and phage rescue from bacterial infections were assessed to demonstrate the efficacy of the application potential. Host range spectrum analysis revealed that phiPA1-3 is a moderate host range phage that infects 20% of the clinically isolated strains of P. aeruginosa tested, including carbapenem-resistant P. aeruginosa (CRPA). The phage exhibited stability at pH 7.0 and 9.0, with significantly reduced viability below pH 5.0 and beyond pH 9.0. phiPA1-3 is a lytic phage with a burst size of 619 plaque-forming units/infected cell at 37°C and can effectively lyse bacteria in a multiplicity of infection-dependent manner. The genome size of phiPA1-3 was found to be 73,402 bp, with a G+C content of 54.7%, containing 93 open reading frames, of which 62 were annotated as hypothetical proteins and the remaining 31 had known functions. The phage possesses several proteins similar to those found in N4-like phages, including three types of RNA polymerases. This study concluded that phiPA1-3 belongs to the N4-like Schitoviridae family, can potentially eradicate P. aeruginosa biofilms, and thus, serve as a valuable tool for controlling CRPA infections.}, } @article {pmid37490212, year = {2023}, author = {Spesia, MB and Durantini, EN}, title = {Photosensitizers combination approach to enhance photodynamic inactivation of planktonic and biofilm bacteria.}, journal = {Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology}, volume = {}, number = {}, pages = {}, pmid = {37490212}, issn = {1474-9092}, support = {PICT N°1482/19//Agencia Nacional de Promoción Científica y Tecnológica/ ; PICT N°2391/19//Agencia Nacional de Promoción Científica y Tecnológica/ ; }, abstract = {To improve bacterial photodynamic inactivation (PDI), this work analyzes the photodynamic effect caused by the combination of photosensitizers (PSs) on two bacterial models and different growth mode. Simultaneous administration of PSs from different families, zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPPc[4+]), 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin (TMAP[4+]), meso-tetrakis(9-ethyl-9-methyl-3-carbazoyl)chlorin (TEMCC[4+]) and 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl] chlorin (TAPC) was investigated against Staphylococcus aureus and Escherichia coli, in planktonic form, biofilm and growth curve. Various PSs combinations showed greater inactivation compared to when used separately under the same conditions but at twice the concentration. However, differences were found in the effectiveness of the PSs combinations on Gram positive and negative bacteria, as well as in planktonic or biofilm form. Likewise, the combination of three PSs completely stopped E. coli growth under optimal nutritional conditions. PSs combination allows extending the range of light absorption by agents that absorb in different areas of the visible spectrum. Therefore, PDI with combined PSs increases its antimicrobial capacity using agents' concentrations and light fluences lower than those necessary to cause the same effect as single PS. These advances represent a starting point for future research on the potentiation of PDI promoted by the combined use of PSs.}, } @article {pmid37489629, year = {2023}, author = {Uematsu, T and Yahata, Y and Ohnishi, K and Suzuki, S and Kanehira, M and Tanaka, T and Sudo, S and Suresh, VV and Saito, M}, title = {Irrigation with reduced sodium hypochlorite solution concentration using laser-induced cavitation is effective and safe in rat intraradicular biofilm model.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {}, number = {}, pages = {}, doi = {10.1111/aej.12783}, pmid = {37489629}, issn = {1747-4477}, support = {//Japan Society for Promotion of Science/ ; }, abstract = {This study aimed to investigate the optimal sodium hypochlorite solution (NaOCl) concentration to effectively remove the root canal biofilm without stimulating periradicular inflammation using coronal laser-activated irrigation (CLAI). To compare the efficacy of different NaOCl concentrations combined with CLAI in removing the biofilm, an in vivo intraradicular biofilm rat model was used. Root canals were irrigated using an Er:YAG laser with either 5% or 0.5% NaOCl. Biofilm removal efficacy of CLAI was compared to that of conventional needle irrigation using scanning electron microscopy (SEM) and quantitative polymerase chain reaction (qPCR). Histological observation of CLAI-associated periradicular inflammation was also conducted. In both the 5% and 0.5% CLAI groups, SEM observation showed the opening of the dentin tubules and biofilm removal. qPCR analysis indicated that the residual bacteria counts after cleaning were significantly lower in the 5% and 0.5% CLAI groups than in the conventional needle irrigation and positive control groups (Tukey test, p < 0.05), and no significant difference was observed between the 5% and 0.5% CLAI groups (p > 0.05). Periapical inflammation in the 5% CLAI group revealed the most severe, including significant neutrophilic and lymphocytic infiltration with abscess formation, while only mild vasodilation was observed in the 0.5% CLAI group. CLAI can remove the biofilm independently of chemical action, which avoids the risks associated with high NaOCl concentrations. Therefore, this root canal irrigation technique ensures safety and effectiveness, promising to contribute to new treatment strategies intended to remove intraradicular biofilm.}, } @article {pmid37489537, year = {2023}, author = {Meier, D and Astasov-Frauenhoffer, M and Waltimo, T and Zaugg, LK and Rohr, N and Zitzmann, NU}, title = {Biofilm formation on metal alloys and coatings, zirconia, and hydroxyapatite as implant materials in vivo.}, journal = {Clinical oral implants research}, volume = {}, number = {}, pages = {}, doi = {10.1111/clr.14146}, pmid = {37489537}, issn = {1600-0501}, support = {//Disc materials were provided by Straumann AG, Switzerland./ ; }, abstract = {OBJECTIVES: Composition of implant material and its surface structure is decisive for oral biofilm accumulation. This study investigated biofilm formation on eight different materials.

MATERIALS AND METHODS: Eighteen healthy subjects wore intraoral splints fitted with two sets of eight materials for 24 h: zirconia [ZrO2 ]; silver-gold-palladium [AgAuPd]; titanium zirconium [TiZr]; Pagalinor [PA]; hydroxyapatite [HA]; silver-platinum [AgPt]; titanium aluminum niobium [TAN]; titanium grade4 [TiGr4]. Total biomass was stained by safranin to assess plaque accumulation while conventional culturing (CFU) was conducted to investigate viable parts of the biofilm. Cell viability of human gingival fibroblasts (HGF-1) was assessed in vitro. Statistical evaluation was performed with linear mixed-effects models to compare materials (geometric mean ratios, 95% CI), with the level of significance set at ɑ = .05.

RESULTS: Less biofilm mass and CFU were found on noble metal alloys (AgPt, AgAuPd, and PA). Compared to AgPt, PA had 2.7-times higher biofilm mass value, AgAuPd was 3.9-times, TiGr4 was 4.1-times, TiZr was 5.9-times, TAN was 7.7-times, HA was 7.8-times, and ZrO2 was 9.1-times higher (each p < .001). Similarly, CFU data were significantly lower on AgPt, AgAuPd had 4.1-times higher CFU values, PA was 8.9-times, TiGr4 was 11.2-times, HA was 12.5-times, TiZr was 13.3-times, TAN was 16.9-times, and ZrO2 was 18.5-times higher (each p < .001). HGF-1 viability varied between 47 ± 24.5% (HA) and 94.4 ± 24.6% (PA).

CONCLUSION: Noble alloys are considered as beneficial materials for the transmucosal part of oral implants, as less biofilm mass, lower bacterial counts, and greater cell viability were detected than on titanium- or zirconia-based materials.}, } @article {pmid37489140, year = {2023}, author = {He, S and Wen, H and Yao, N and Wang, L and Huang, J and Li, Z}, title = {A Sustained-Release Nanosystem with MRSA Biofilm-Dispersing and -Eradicating Abilities Accelerates Diabetic Ulcer Healing.}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {3951-3972}, pmid = {37489140}, issn = {1178-2013}, abstract = {INTRODUCTION: Drug-resistant bacterial infections and biofilm formation play important roles in the pathogenesis of diabetic refractory wounds. Tea tree oil (TTO) exhibits antimicrobial, antimycotic, and antiviral activities, especially against common clinically resistant strains, such as methicillin-resistant Staphylococcus aureus (MRSA), making it a potential natural antimicrobial for the treatment of acute and chronic wounds. However, TTO is insoluble in water, volatile, light-sensitive, and cytotoxic. While previous macroscopic studies have focused on sterilization with TTO, none have sought to alter its structure or combine it with other materials to achieve sustained release.

METHODS: Electrospun TTO nanoliposomes (TTO-NLs), arranged linearly via high-pressure homogenization, could stabilize the structure and performance of TTO to achieve slow drug release. Herein, we established a composite nano-sustained release system, TTO-NL/polyvinyl alcohol/chitosan (TTO-NL@PCS), using high-voltage electrospinning.

RESULTS: Compared with the control, TTO-NL@PCS exhibits higher concentrations of the active TTO drug components, terpinen-4-ol and 1,8-cineole. Owing to its increased stability and slow release, early exposure to TTO-NL@PCS increases the abundance of reactive oxygen species in vitro, ultimately causing the biofilm to disperse and completely killing MRSA without inducing cytotoxic effects to the host. Moreover, in BKS-Lepr[em2Cd479]/Gpt mice with a whole-layer skin infection, untargeted metabolomics analysis of wound exudates reveals upregulated PGF2α/FP receptor signaling and interleukin (IL)-1β and IL-6 expression following application of the composite system. The composite also ameliorates the chemotaxis disorder in early treatment and attenuates the wound inflammatory response during the repair stage of diabetic inflammatory wounds, and upregulates VEGF expression in the wound bed.

CONCLUSION: TTO-NL@PCS demonstrates the remarkable potential for accelerating diabetic and MRSA-infected wound healing.}, } @article {pmid37488203, year = {2023}, author = {Kim, J and Kang, SH and Choi, Y and Lee, W and Kim, N and Tanaka, M and Kang, SH and Choi, J}, title = {Antibacterial and biofilm-inhibiting cotton fabrics decorated with copper nanoparticles grown on graphene nanosheets.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {11947}, pmid = {37488203}, issn = {2045-2322}, support = {2020R1A5A1018052//National Research Foundation of Korea/ ; 2017M3A7B8061942//National Research Foundation of Korea/ ; 2019R1A2C1006018//National Research Foundation of Korea/ ; 2021M3H4A4079629//National Research Foundation of Korea/ ; }, abstract = {Infectious pathogens can be transmitted through textiles. Therefore, additional efforts are needed to develop functional fabrics containing antimicrobial substances to prevent the growth of antibiotic-resistant bacteria and their biofilms. Here, we developed a cotton fabric coated with reduced graphene oxide (rGO) and copper nanoparticles (Cu NPs), which possessed hydrophobic, antimicrobial, and anti-biofilm properties. Once the graphene oxide was dip-coated on a cellulose cotton fabric, Cu NPs were synthesized using a chemical reduction method to fabricate an rGO/Cu fabric, which was analyzed through FE-SEM, EDS, and ICP-MS. The results of our colony-forming unit assays indicated that the rGO/Cu fabric possessed high antibacterial and anti-biofilm properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Corynebacterium xerosis, and Micrococcus luteus. Particularly, the fabric could inhibit the growth of E. coli, C. xerosis, and M. luteus with a 99% efficiency. Furthermore, our findings confirmed that the same concentrations of rGO/Cu had no cytotoxic effects against CCD-986Sk and Human Dermal Fibroblast (HDF), human skin cells, and NIH/3T3, a mouse skin cell. The developed rGO/Cu fabric thus exhibited promising applicability as a cotton material that can maintain hygienic conditions by preventing the propagation of various bacteria and sufficiently suppressing biofilm formation while also being harmless to the human body.}, } @article {pmid37488008, year = {2023}, author = {Kiani, P and Soozanipour, A and Rezayat, A and Taheri-Kafrani, A}, title = {Lysozyme-immobilized bandage contact lens inhibits the growth and biofilm formation of common eye pathogens in vitro.}, journal = {Experimental eye research}, volume = {}, number = {}, pages = {109601}, doi = {10.1016/j.exer.2023.109601}, pmid = {37488008}, issn = {1096-0007}, abstract = {Bandage contact lenses have an increased affinity to accumulate tear film proteins and bacteria during wear. Among the wide variety of tear film proteins, lysozyme has attracted the most attention for several reasons, including the fact that it is found at a high concentration in the tear film, has exceptional antibacterial and antibiofilm properties, and its significant deposits onto contact lenses. This study aims to evaluate the effect of lysozyme on bacterial biofilm formation on bandage contact lenses. For this purpose, several methods, including microtiter plate test and Colony Forming Unit (CFU) assay have been used to determine antibacterial and antibiofilm characteristics of lysozyme against the two most frequent contact lens-induced bacterial ocular infections, Staphylococcus aureus, and Pseudomonas aeruginosa. The results of these assays demonstrate lysozyme potential to inhibit 57.9% and 80.7% of the growth of S. aureus and P. aeruginosa, respectively. In addition, biofilm formations of P. aeruginosa and S. aureus reduced by 38.3% and 62.7%, respectively due to the antibiofilm effect of lysozyme. SEM and AFM imaging were utilized to visualize lysozyme antibacterial activity and topography changes of the contact lens surface, respectively, in the presence/absence of lysozyme. The results indicated that lysozyme can efficiently attack both gram-positive and gram-negative bacteria and consequently lysozyme-functionalized bandage contact lenses can reduce the risk of ocular infection after eye surgery.}, } @article {pmid37487904, year = {2023}, author = {Yuan, L and Fan, L and Dai, H and He, G and Zheng, X and Rao, S and Yang, Z and Jiao, XA}, title = {Multi-omics reveals the increased biofilm formation of Salmonella Typhimurium M3 by the induction of tetracycline at sub-inhibitory concentrations.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {165695}, doi = {10.1016/j.scitotenv.2023.165695}, pmid = {37487904}, issn = {1879-1026}, abstract = {Exposure to sub-inhibitory concentrations (sub-MICs) of antibiotics could induce the biofilm formation of microorganisms, but its underlying mechanisms still remain elusive. In the present work, biofilm formation by Salmonella Typhimurium M3 was increased when in the presence of tetracycline at sub-MIC, and the highest induction was observed with tetracycline at 1/8 MIC. The integration of RNA-sequencing and untargeted metabolomics was applied in order to further decipher the potential mechanisms for this observation. In total, 439 genes and 144 metabolites of S. Typhimurium M3 were significantly expressed after its exposure to 1/8 MIC of tetracycline. In addition, the co-expression analysis revealed that 6 genes and 8 metabolites play a key role in response to 1/8 MIC of tetracycline. The differential genes and metabolites were represented in 12 KEGG pathways, including five pathways of amino acid metabolism (beta-alanine metabolism, tryptophan metabolism, arginine and proline metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and glutathione metabolism), three lipid metabolism pathways (biosynthesis of unsaturated fatty acids, fatty acid degradation, and fatty acid biosynthesis), two nucleotide metabolism pathways (purine metabolism, and pyrimidine metabolism), pantothenate and CoA biosynthesis, and ABC transporters. Metabolites (anthranilate, indole, and putrescine) from amino acid metabolism may act as signaling molecules to promote the biofilm formation of S. Typhimurium M3. The results of this work highlight the importance of low antimicrobial concentrations on foodborne pathogens of environmental origin.}, } @article {pmid37487794, year = {2023}, author = {Noubam-Tchatat, C and Badrikian, L and Traore, O and Aumeran, C}, title = {Evaluation of two detergent-disinfectants and a detergent on a Klebsiella pneumoniae biofilm formed within Tygon tubes.}, journal = {The Journal of hospital infection}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jhin.2023.04.019}, pmid = {37487794}, issn = {1532-2939}, abstract = {BACKGROUND: Transmission of infections via contaminated endoscopes is a common problem. Manual cleaning, using at least a detergent, is an important step in endoscope processing and should be performed as soon as possible to avoid drying of organic residues that might interfere with high level-disinfection and promote biofilm formation.

AIM: We assessed the efficacy of two detergent-disinfectants, enzymatic and non-enzymatic, and of an enzymatic detergent used during the manual cleaning against a Klebsiella pneumoniae biofilm.

METHODS: A 24-hour biofilm statically formed in a Tygon tube was exposed to detergent-disinfectants at 20°C and 35°C for 10 mn, and to enzymatic detergent at 45°C for 60 mn. The logarithmic reduction in bacteria in the Tygon tube and the number of bacteria in the product supernatant were calculated.

FINDINGS: Biofilm formation was reproducible between assays. After exposure to detergent-disinfectants, the logarithmic reduction was between 6.32 and 6.71 log10CFU/cm[2] in the Tygon tubes. No bacteria were found in their supernatants. Results in the detergent-disinfectant group were not affected by the exposure temperature or the addition of enzymes. No decrease in the bacterial load was observed in the Tygon tubes after exposure to the enzymatic detergent. Bacteria were found in its supernatant.

CONCLUSION: Our results show the importance of the choice of products used during the manual cleaning phase. They also show the interest of combining detergent and disinfectant activity to decrease the bacterial load during the manual cleaning step of endoscope processing.}, } @article {pmid37483388, year = {2023}, author = {Parikh, S and Patel, J and Patel, R and Patel, R}, title = {Editorial: Novel approaches in the prevention of bacterial biofilm formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1212386}, pmid = {37483388}, issn = {2235-2988}, } @article {pmid37483315, year = {2023}, author = {Tsai, MJ and Lin, CY and Trousil, J and Sung, CT and Lee, MH and Fang, JY and Yang, SC}, title = {Proteinase K/Retinoic Acid-Loaded Cationic Liposomes as Multifunctional Anti-Acne Therapy to Disorganize Biofilm and Regulate Keratinocyte Proliferation.}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {3879-3896}, pmid = {37483315}, issn = {1178-2013}, abstract = {BACKGROUND: Simultaneous anti-Cutibacterium acnes and anti-inflammatory actions are highly beneficial in treating acne vulgaris. In this study, we present novel anti-acne nanovesicles based on liposomes loaded with proteinase K (PK), retinoic acid (RA), and soyaethyl morpholinium ethosulfate (SME) to achieve an effective and safe treatment.

MATERIALS AND METHODS: This study examined in vitro planktonic and biofilm C. acnes elimination, as well as the keratinocyte proliferation suppression by liposomes. The multifunctional liposomes for treating C. acnes in mice were also evaluated.

RESULTS: We acquired multifunctional liposomes with a size of 71 nm and zeta potential of 31 mV. The antimicrobial activity of SME was enhanced after liposomal encapsulation according to the reduction of minimum bactericidal concentration (MBC) by 6-fold. The multifunctional liposomes exhibited a synergistically inhibitory effect on biofilm C. acnes colonization compared with the liposomes containing PK or those containing SME individually. The adhesive bacterial colony in the microplate was lessened by 62% after multifunctional liposome intervention. All liposomal formulations tested here demonstrated no cytotoxicity against the normal keratinocytes but inhibited C. acnes-stimulated cell hyperproliferation. The in vitro scratch assay indicated that the liposomal RA-but not free RA-restrained keratinocyte migration. The animal study showed that free RA combined with SME and multifunctional nanovesicles had a similar effect on diminishing C. acnes colonies in the skin. On the other hand, liposomes exhibited superior performance in recovering the impaired skin barrier function than the free control. We also found that RA-loaded nanovesicles had greater skin tolerability than free RA.

CONCLUSION: The cationic liposomes containing dual PK and RA represented a potential treatment to arrest bacterial infection and associated inflammation in acne.}, } @article {pmid37482932, year = {2023}, author = {Sajayan, A and Ravindran, A and Selvin, J and Ragothaman, P and Seghal Kiran, G}, title = {An antimicrobial metabolite n- hexadecenoic acid from marine sponge-associated bacteria Bacillus subtilis effectively inhibited biofilm forming multidrug-resistant P. aeruginosa.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/08927014.2023.2232722}, pmid = {37482932}, issn = {1029-2454}, abstract = {Effective drug candidates to obstruct the emergence of multidrug-resistant pathogens have become a major concern. A potent antimicrobial producer was isolated from a marine sponge designated as MSI38 and was identified as Bacillus subtilis by 16SrDNA sequencing. The active antimicrobial fraction was purified, and the metabolite was identified as n-hexadecanoic acid by spectroscopic analysis. The fish-borne pathogen Pseudomonas aeruginosa FP012 was found to be multidrug-resistant and poses a risk of disease to food handlers and consumers in general. The compound showed a potent bactericidal effect against P. aeruginosa FP012 with a MIC of 31.33 ± 5.67 mg L[-1] and MBC of 36.66 ± 5.17 mg L[-1]. The time-based biofilm inhibitory potential of MSI38 and ciprofloxacin was analyzed by confocal laser scanning microscopy. A synergistic effect of MSI38 and ciprofloxacin on biofilm showed 85% inhibition.}, } @article {pmid37482852, year = {2023}, author = {Wahman, S and Shawky, RM and Emara, M}, title = {Biologically-Relevant Staphylococcus Aureus Biofilm Phenotype Characterisation And Liability To Novel Antibiofilm Drugs.}, journal = {JPMA. The Journal of the Pakistan Medical Association}, volume = {73(Suppl 4)}, number = {4}, pages = {S167-S173}, doi = {10.47391/JPMA.EGY-S4-34}, pmid = {37482852}, issn = {0030-9982}, abstract = {OBJECTIVES: To characterise the biofilm matrix composition of a newly described Staphylococcus aureus biofilm phenotype.

METHOD: This experimental study was conducted at the Faculty of Pharmacy, Helwan University, Cairo, Egypt, from January 2021 to March 2022, and comprised methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus biofilm-forming clinical isolates which were allowed to construct biofilms under two distinct culture conditions; one a commonly used condition, and the other one a novel, more biologically-relevant condition. The formed biofilms were analysed for matrix composition through treatment with proteinase,sodium meta-periodate, and streptokinase. The efficacy of Cis-2-Decenoic acid and hamamelitannin on the biologically-relevant biofilms was evaluated using biofilm viability assay based on a colorimetric assay for measuring cell metabolic activity and scanning electron microscope imaging. Data was analysed using GraphPad Prism 5.01.

RESULTS: Of the 58 isolates, 45(77.6%) were methicillin-resistant Staphylococcus aureus and 13(22.4%) were methicillin susceptible Staphylococcus aureus. There was significant difference in responses to streptokinase, proteinase and sodium meta-periodate (p<0.05) among the differentially-developed biofilms in methicillin-resistant Staphylococcus aureus isolates. Regarding the methicillin-susceptible Staphylococcus aureus isolates, the differentially-developed biofilms showed significantly different liabilities to streptokinase only (p<0.05). Mean biofilm inhibition for Cis-2- Decenoic acid was 54.27±27.93% and mean biofilm dispersion was 71.92±11.59% while the corresponding valuesfor hamamelitannin were 83.03±13.95% and 70.48±7.116% against the newly described methicillin-resistant Staphylococcus aureus biofilm phenotype.

CONCLUSIONS: Applying biologically-relevant culture conditions on staphylococci biofilms and antibiofilm drugs is recommended.}, } @article {pmid37482281, year = {2023}, author = {Puges, M and Bérard, X and Vilain, S and Pereyre, S and Svahn, I and Caradu, C and Mzali, F and Cazanave, C}, title = {Staphylococcus aureus Adhesion and Biofilm Formation on Vascular Polyester Grafts are Inhibited In Vitro by Triclosan.}, journal = {European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ejvs.2023.07.018}, pmid = {37482281}, issn = {1532-2165}, abstract = {OBJECTIVE: This study evaluated Staphylococcus aureus adhesion and biofilm formation on vascular grafts, which has seldom been investigated.

METHODS: Adhesion and biofilm formation capabilities of three methicillin-susceptible S. aureus strains (one biofilm-forming reference strain and two clinical isolates) on five different vascular biomaterials were evaluated in vitro, including polyester (P), P+gelatin (PG), P+collagen (PC), PC+silver (PCS), and PCS+triclosan (PCST). Staphylococcus aureus adhesion on grafts was evaluated after 1 hour of culture and biofilm formation after 24 hours of culture by four different methods: spectrophotometry after crystal violet staining; sonicate fluid culture; metabolic assay; and scanning electron microscopy (SEM). Optical density was compared using Mann-Whitney pairwise test, and bacterial counts using Wilcoxon pairwise test.

RESULTS: PCST grafts were most efficient in preventing S. aureus adhesion and biofilm formation, regardless of the method used. Bacterial counts and metabolic activity were significantly lower on PCST grafts after 24 hours [5.65 vs. 9.24 (PCS), 8.99 (PC), 8.82 (PG), and 10.44 log10 CFU/mL (P); p < .015], and only PCST grafts were bactericidal. Biofilm formation was significantly diminished on PCST grafts compared with all other grafts (p < .001). Bacterial viability and metabolic activity after 24 hours were more impaired on PG compared with PC grafts, and were surprisingly higher on PCS compared with PC grafts. Biofilm biomass formed after exposure to P, PG, PC, and PCS grafts was also reduced after 24 hours of incubation with PCST grafts (p < .001). After 24 hours, few bacteria were visible by SEM on PCST grafts, whereas bacterial biofilm colonies were clearly identified on other graft surfaces.

CONCLUSION: Triclosan impregnated PCST grafts appeared to interfere with S. aureus adhesion from early stages of biofilm formation in vitro. Silver impregnation was not efficient in preventing biofilm formation, and collagen coating promoted S. aureus biofilm formation more than gelatin coating.}, } @article {pmid37482002, year = {2023}, author = {Hu, Z and Liu, T and Su, Z and Zhao, J and Guo, J and Hu, S and Yuan, Z and Zheng, M}, title = {Adaptation of anammox process for nitrogen removal from acidic nitritation effluent in a low pH moving bed biofilm reactor.}, journal = {Water research}, volume = {243}, number = {}, pages = {120370}, doi = {10.1016/j.watres.2023.120370}, pmid = {37482002}, issn = {1879-2448}, abstract = {Acidic partial nitritation (PN) has emerged to be a promisingly stable process in wastewater treatment, which can simultaneously achieve nitrite accumulation and about half of ammonium reduction. However, directly applying anaerobic ammonium oxidation (anammox) process to treat the acidic PN effluent (pH 4-5) is susceptible to the inhibition of anammox bacteria. Here, this study demonstrated the adaptation of anammox process to acidic pH in a moving bed biofilm reactor (MBBR). By feeding the laboratory-scale MBBR with acidic PN effluent (pH = 4.6 ± 0.2), the pH of an anammox reactor was self-sustained in the range of pH 5 - 6. Yet, a high total nitrogen removal efficiency of over 80% at a practical loading rate of up to 149.7 ± 3.9 mg N/L/d was achieved. Comprehensive microbial assessment, including amplicon sequencing, metagenomics, cryosection-FISH, and qPCR, identified that Candidatus Brocadia, close to known neutrophilic members, was the dominant anammox bacteria. Anammox bacteria were found present in the inner layer of thick biofilms but barely present in the surface layer of thick biofilms and in thin biofilms. Results from batch tests also showed that the activity of anammox biofilms could be maintained when subjected to pH 5 at a nitrite concentration of 10 mg N/L, whereas the activity was completely inhibited after disturbing the biofilm structure. These results collectively indicate that the anammox bacteria enriched in the present acidic MBBR could not be inherently acid-tolerant. Instead, the achieved stable anammox performance under the acidic condition is likely due to biofilm stratification and protection. This result highlights the biofilm configuration as a useful solution to address nitrogen removal from acidic PN effluent, and also suggests that biofilm may play a critical role in protecting anammox bacteria found in many acidic nature environments.}, } @article {pmid37479594, year = {2023}, author = {Thu, KM and Yeung, AWK and Samaranayake, L and Lam, WYH}, title = {Denture Plaque Biofilm Visual Assessment Methods: A Systematic Review.}, journal = {International dental journal}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.identj.2023.06.010}, pmid = {37479594}, issn = {1875-595X}, abstract = {Denture plaque, a biofilm that develops on denture surfaces, could contribute to many oral and systemic afflictions. Hence, a quantitative assessment of denture plaque is important to evaluate the denture hygiene of denture wearers, particularly to prevent plaque biofilm-associated diseases. The aim of this systematic review, therefore, was to review and summarize the visual denture hygiene assessment methods using denture plaque indices and with planimetries published in the literature. English language studies published up to March 2022 in four electronic databases, PubMed, Medline, Embase, and Cochrane Library, were searched, followed by a manual search of Google Scholar by two assessors. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) whenever possible. Details of the visual assessment methods, including the types of denture assessed, its materials and its surfaces, as well as the use of a disclosing agent, were the main outcomes. Of 492 screened studies, 74 were included per the inclusion and exclusion criteria. Of these, 60 studies utilized various denture plaque indices while 18 used planimetries. 43 out of 60 studies with indices and 17 out of 18 studies with planimetries used disclosing agents for visual evaluation of plaque. A total of 21 indices were described in the included studies, of which seven graded a divided denture surface, while the remainder graded entire denture surface. Of the 18 planimetric assessments, one study quantified squares of the disclosed plaques on denture images, 16 studies quantified such pixels with computer programs, and a single study quantified points, pixels, and contour of plaque areas. In summary, denture plaque indices appear to be popular in denture plaque assessment due to their simplicity. Computerized planimetric assessment, though more time-consuming, provides a more accurate assessment of plaque load as it is less prone to subjectivity and assessor errors.}, } @article {pmid37479559, year = {2023}, author = {Rohatgi, A and Gupta, P}, title = {Benzoic acid derivatives as potent antibiofilm agents against Klebsiella pneumoniae biofilm.}, journal = {Journal of bioscience and bioengineering}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jbiosc.2023.06.011}, pmid = {37479559}, issn = {1347-4421}, abstract = {Klebsiella pneumoniae is responsible for a significant proportion of human urinary tract infections, and its biofilm is a major virulence. One potential approach to controlling biofilm-associated infections is targeting the adhesin MrkD1P to disrupt biofilm formation. We employed Schrodinger's Maestro tool with the OPLS 2005 force field to dock compounds with the target protein. Two benzoic acid derivatives, 3-hydroxy benzoic acid and 2,5-dihydroxybenzoic acid, had strong binding free energies (-55.57 and -18.68 kcal/mol) and were the most potent compounds. The in-vitro experiments were conducted to validate the in-silico results. The results showed that both compounds effectively inhibited biofilm formation at low concentrations (4 and 8 mg/mL, respectively) and had antibiofilm activity, restricting cell attachment. Both compounds demonstrated a strong biofilm inhibitory effect, with 97% and 89% reduction in biofilm by 3-hydroxy benzoic acid and 2,5-dihydroxybenzoic acid, respectively. These findings suggest that natural compounds can be a potential source of new drugs to combat biofilm-associated infections. The study highlights the potential of targeting adhesin MrkD1P as an effective approach to controlling biofilm-associated infections caused by K. pneumoniae. The results may have implications for the development of new therapies for biofilm-associated infections and pave the way for future research in this area.}, } @article {pmid37479531, year = {2023}, author = {Sun, C and Zhou, X and Liu, C and Deng, S and Song, Y and Yang, J and Dai, J and Ju, Y}, title = {An Integrated Therapeutic And Preventive Nanozyme-Based Microneedle for Biofilm-Infected Diabetic Wound Healing.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2301474}, doi = {10.1002/adhm.202301474}, pmid = {37479531}, issn = {2192-2659}, abstract = {The healing of biofilm-infected diabetic wounds characterized by deteriorative tissue microenvironment represents a substantial clinical challenge. Current treatments remain unsatisfactory due to the limited antibiofilm efficacy caused by weak tissue and biofilm permeability of drugs and the risk of reinfection during the healing process. To address these issues, an integrated therapeutic and preventive nanozyme-based microneedle (denoted as Fe2 C/GOx@MNs) is engineered in this paper. The dissolvable tips with enough mechanical strength can delivery and rapidly release Fe2 C nanoparticles (NPs)/glucose oxidase (GOx) in the biofilm active regions, enhancing tissue and biofilm permeability of Fe2 C NPs/GOx, ultimately achieving highly efficient biofilm elimination. Meanwhile, the chitosan backing layer can not only act as an excellent physical barrier between the wound bed and the external environment, but also prevent the bacterial reinvasion during wound healing with its superior antibacterial property. Significantly, the biofilm elimination and reinfection prevention abilities of Fe2 C/GOx@MNs on wound healing are proved on methicillin-resistant Staphylococcus aureus-biofilm-infected diabetic mouse model with full-thickness wound. Together, these results demonstrate the promising clinical application of Fe2 C/GOx@MNs in biofilm-infected wound healing. This article is protected by copyright. All rights reserved.}, } @article {pmid37479094, year = {2023}, author = {Veigyabati Devi, M and Kumar Singh, A}, title = {Delineation of transcriptional regulators involve in biofilm formation cycle of Mycobacterium abscessus.}, journal = {Gene}, volume = {}, number = {}, pages = {147644}, doi = {10.1016/j.gene.2023.147644}, pmid = {37479094}, issn = {1879-0038}, abstract = {Mycobacterium abscessus is an intrinsically and acquired multidrug resistant (MDR) intracellular pathogen with biofilm formation capability and limited option for treatment. Biofilm is the major characteristic that leads to failure and prolong treatment, intensifies treatment cost and increases mortality/morbidity rate. However, the biofilm formation regulations of M. abscessus remain largely unexplored. In this study, we identify the putative/hypothetical transcriptional regulator (TR) of M. abscessus that are involved in biofilm formation. This study includes fifty TRs belonging to thirteen different families viz., AraC, ArsR, AsnC, CarD, CdaR, GntR, IclR, LysR, MarR, PadR, PrrA, TetR and WhiB, including TRs of unknown family. The promoter of these putative TRs were fused individually with GFP and analyzed their expression using CLSM in planktonic phase and early, mid and mature stages of biofilm formation phase, which overall termed as biofilm formation cycle. Further, qRT-PCR was carried out for selected TRs to analyze their differential expressions. This study found thirteen numbers of TR belonging to TetR family, five TRs belonging to MarR family, four TRs of unannotated TR family, two AraC TRs, two LysR, two GntR, two AsnC, one each of ArsR family, CarD family, IclR family, PadR family, PrrA family and WhiB family selected for this study are involved in biofilm formation cycle. Our study characterized the TRs with respect to their role in biofilm formation for the first time in M. abscessus and also found that their biofilm formation is regulated by diverse TR families.}, } @article {pmid37478779, year = {2023}, author = {Biswas, S and Wasai, A and Ghosh, M and Rizzoli, C and Roy, A and Saha, S and Mandal, S}, title = {A mononuclear N,N,N,O donor schiff base Cu(II) complex inhibits bacterial biofilm formation and promotes apoptosis and cell cycle arrest in prostate cancer cells.}, journal = {Journal of inorganic biochemistry}, volume = {247}, number = {}, pages = {112314}, doi = {10.1016/j.jinorgbio.2023.112314}, pmid = {37478779}, issn = {1873-3344}, abstract = {In this work, we report a distorted square pyramidal mononuclear copper(II) complex [Cu(L)(NCS)] (1) which was obtained by the reaction of the aqueous solution of ammonium thiocyanate to a methanolic solution of copper nitrate trihydrate and corresponding Schiff-base ligands. Schiff bases, HL (C12H19N3O) act as a tetradentate Schiff base, derived from 1:1 condensation of o-hydroxyacetophenone and diethylenetriamine. The synthesized complex has been successfully characterized based on elemental analysis and Infrared (IR) spectroscopy. The structure of complex 1 was confirmed by single-crystal X-ray diffraction study. In our study, we investigated synthesis, structural characterization, antimicrobial, anti-biofilm, and anti-cancer activity, and plausible mechanism of action of a novel mononuclear copper(II) schiff base complex. Increasing microbial resistance to several commercially available or traditional antimicrobial compounds has become a major global health concern at present time. The mononuclear copper(II) complex exhibited potential antibacterial activity against two strains of the gram-negative pathogen Pseudomonas aeruginosa. The copper compound dependent damage of bacterial cell membrane and inhibition of bacterial biofilm formation were also identified. Moreover, complex 1 inhibited prostate cancer cell growth, and migration by inducing apoptosis and arresting the cell cycle at the G2/M phase. Based on the results, we are suggesting our novel mononuclear copper(II) compound as a potential candidate for the development of new antibacterial and anti-cancer drugs.}, } @article {pmid37478472, year = {2023}, author = {Ke, Y and Sun, W and Chen, X and Zhu, Y and Guo, X and Yan, W and Xie, S}, title = {Seasonality Determines the Variations of Biofilm Microbiome and Antibiotic Resistome in a Pilot-Scale Chlorinated Drinking Water Distribution System Deciphered by Metagenome Assembly.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c01980}, pmid = {37478472}, issn = {1520-5851}, abstract = {Understanding the biofilm microbiome and antibiotic resistome evolution in drinking water distribution systems (DWDSs) is crucial to ensure the safety of drinking water. We explored the 10 month evolution of the microbial community, antibiotic resistance genes (ARGs), mobile gene elements (MGEs) co-existing with ARGs and pathogenic ARG hosts, and the ARG driving factors in DWDS biofilms using metagenomics assembly. Sampling season was critical in determining the microbial community and antibiotic resistome shift. Pseudomonas was the primary biofilm colonizer, and biofilms diversified more as the formation time increased. Most genera tended to cooperate to adapt to an oligotrophic environment with disinfectant stress. Biofilm microbial community and antibiotic resistome assembly were mainly determined by stochastic processes and changed with season. Metagenome assembly provided the occurrence and fates of MGEs co-existing with ARGs and ARG hosts in DWDS biofilms. The abundance of ARG- and MGE-carrying pathogen Stenotrophomonas maltophilia was high in summer. It primarily harbored the aph(3)-IIb, multidrug transporter, smeD, and metallo-beta-lactamase ARGs, which were transferred via recombination. The microbial community was the most crucial factor driving the antibiotic resistance shift. We provide novel insights about the evolution of pathogens and ARGs and their correlations in DWDS biofilms to ensure the safety of drinking water.}, } @article {pmid37477959, year = {2023}, author = {Zhang, Y and Young, P and Traini, D and Li, M and Ong, HX and Cheng, S}, title = {Challenges and current advances in in vitro biofilm characterization.}, journal = {Biotechnology journal}, volume = {}, number = {}, pages = {e2300074}, doi = {10.1002/biot.202300074}, pmid = {37477959}, issn = {1860-7314}, abstract = {Biofilms are structured communities of bacterial cells encased in a self-produced polymeric matrix, which develop over time and exhibit temporal responses to stimuli from internal biological processes or external environmental changes. They can be detrimental, threatening public health and causing economic loss, while they also play beneficial roles in ecosystem health, biotechnology processes, and industrial settings. Biofilms express extreme heterogeneity in their physical properties and structural composition, resulting in critical challenges in understanding them comprehensively. The lack of detailed knowledge of biofilms and their phenotypes has deterred significant progress in developing strategies to control their negative impacts and take advantage of their beneficial applications. A range of in vitro models and characterization tools have been developed and used to study biofilm growth and, specifically, to investigate the impact of environmental and growth factors on their development. This review article discusses the existing knowledge of biofilm properties and explains how external factors, such as flow condition, surface, interface, and host factor, may impact biofilm growth. The limitations of current tools, techniques and in vitro models that are currently used for biofilms are also presented. This article is protected by copyright. All rights reserved.}, } @article {pmid37477280, year = {2023}, author = {Ashrafudoulla, M and Mevo, SIU and Song, M and Chowdhury, MAH and Shaila, S and Kim, DH and Nahar, S and Toushik, SH and Park, SH and Ha, SD}, title = {Antibiofilm mechanism of peppermint essential oil to avert biofilm developed by foodborne and food spoilage pathogens on food contact surfaces.}, journal = {Journal of food science}, volume = {}, number = {}, pages = {}, doi = {10.1111/1750-3841.16712}, pmid = {37477280}, issn = {1750-3841}, support = {//This work was supported by theMinistry of Food and Drug Safety in 2022/ ; 21153MFDS605//This research was also supported by the Chung-Ang University Research Grants in 2022/ ; //Ministry of Food and Drug Safety/ ; }, abstract = {Establishing efficient methods to combat bacterial biofilms is a major concern. Natural compounds, such as essential oils derived from plants, are among the favored and recommended strategies for combatting bacteria and their biofilm. Therefore, we evaluated the antibiofilm properties of peppermint oil as well as the activities by which it kills bacteria generally and particularly their biofilms. Peppermint oil antagonistic activities were investigated against Vibrio parahaemolyticus, Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli O157:H7, and Salmonella Typhimurium on four food contact surfaces (stainless steel, rubber, high-density polyethylene, and polyethylene terephthalate). Biofilm formation on each studied surface, hydrophobicity, autoaggregation, metabolic activity, and adenosine triphosphate quantification were evaluated for each bacterium in the presence and absence (control) of peppermint oil. Real-time polymerase chain reaction, confocal laser scanning microscopy, and field-emission scanning electron microscopy were utilized to analyze the effects of peppermint oil treatment on the bacteria and their biofilm. Results showed that peppermint oil (1/2× minimum inhibitory concentration [MIC], MIC, and 2× MIC) substantially lessened biofilm formation, with high bactericidal properties. A minimum of 2.5-log to a maximum of around 5-log reduction was attained, with the highest sensitivity shown by V. parahaemolyticus. Morphological experiments revealed degradation of the biofilm structure, followed by some dead cells with broken membranes. Thus, this study established the possibility of using peppermint oil to combat key foodborne and food spoilage pathogens in the food processing environment.}, } @article {pmid37477228, year = {2023}, author = {Yue, Y and Zhong, K and Wu, Y and Gao, H}, title = {Pyrrole-2-carboxylic acid inhibits biofilm formation and suppresses the virulence of Listeria monocytogenes.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/08927014.2023.2235287}, pmid = {37477228}, issn = {1029-2454}, abstract = {Bacterial adhesion and biofilm formation of Listeria monocytogenes on food-contact surfaces result in serious safety concerns. This study aimed to explore the antibiofilm efficacy of pyrrole-2-carboxylic acid (PCA) against L. monocytogenes. Crystal violet staining assay demonstrated that PCA reduced the biofilm biomass of L. monocytogenes. The 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide reduction and flow cytometric assays indicated that PCA attenuated the metabolic activity of L. monocytogenes biofilm together with a decrease in viability. Morphologic observations revealed that PCA exposure collapsed the biofilm architecture. PCA administration of 0.75 mg ml[-1] decreased the excretion of extracellular DNA, protein and polysaccharide by 48.58%, 61.60% and 75.63%, respectively. PCA failed to disperse the mature biofilm, even at 1.5 mg ml[-1]. However, PCA suppressed L. monocytogenes adhesion on common food-contact surfaces. Additionally, PCA exposure suppressed the hemolytic activity of L. monocytogenes. These findings suggested that PCA might serve as an alternative antibiofilm agent to control L. monocytogenes contamination.}, } @article {pmid37474092, year = {2023}, author = {Elumalai, L and Palaniyandi, S and Anbazhagan, GK and Mohanam, N and Munusamy, S and G K, SR and Pudukadu Munusamy, A and Chinnasamy, M and Ramasamy, B}, title = {Synthesis of biogenic cadmium sulfide nanoparticles (MR03-CdSNPs) using marine Streptomyces kunmingensis - MR03 for invitro biological determinations and in silico analysis on biofilm virulence proteins: A novel approach.}, journal = {Environmental research}, volume = {}, number = {}, pages = {116698}, doi = {10.1016/j.envres.2023.116698}, pmid = {37474092}, issn = {1096-0953}, } @article {pmid37473897, year = {2023}, author = {Chauhan, J and Sharma, RK}, title = {Synbiotic formulations with microbial biofilm, animal derived (casein, collagen, chitosan) and plant derived (starch, cellulose, alginate) prebiotic polymers: A review.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {125873}, doi = {10.1016/j.ijbiomac.2023.125873}, pmid = {37473897}, issn = {1879-0003}, abstract = {The need for a broader range of probiotics, prebiotics, and synbiotics to improve the activity and functioning of gut microbiota has led to the development of new nutraceuticals formulations. These techniques majorly depend on the type of the concerned food, inclusive factors i.e. application of biotic components, probiotics, and synbiotics along with the type of encapsulation involved. For improvisation of the oral transfer mode of synbiotics delivery within the intestine along with viability, efficacy, and stability co-encapsulation is required. The present study explores encapsulation materials, probiotics and prebiotics in the form of synbiotics. The emphasis was given to the selection and usage of probiotic delivery matrix or prebiotic polymers, which primarily include animal derived (gelatine, casein, collagen, chitosan) and plant derived (starch, cellulose, pectin, alginate) materials. Beside this, the role of microbial polymers and biofilms (exopolysaccharides, extracellular polymeric substances) has also been discussed in the formation of probiotic functional foods. In this instance, the microbial biofilm is also used as suitable polymeric compound for encapsulation providing stability, viability, and efficacy. Thus, the review highlights the utilization of diverse prebiotic polymers in synbiotic formulations, along with microbial biofilms, which hold great potential for enhancing gut microbiota activity and improving overall health.}, } @article {pmid37475017, year = {2023}, author = {Jabalameli, F and Emaneini, M and Beigverdi, R and Halimi, S and Siroosi, M}, title = {Determining effects of nitrate, arginine, and ferrous on antibiotic recalcitrance of clinical strains of Pseudomonas aeruginosa in biofilm-inspired alginate encapsulates.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {22}, number = {1}, pages = {61}, pmid = {37475017}, issn = {1476-0711}, abstract = {BACKGROUND: Biofilms play a role in recalcitrance and treatability of bacterial infections, but majority of known antibiotic resistance mechanisms are biofilm-independent. Biofilms of Pseudomonas aeruginosa, especially in cystic fibrosis patients infected with the alginate producing strains in their lungs, are hard to treat. Changes in growth-related bacterial metabolism in biofilm affect their antibiotic recalcitrance which could be considered for new therapies designed based on these changes. In this study, effects of nitrate, arginine, and ferrous were investigated on antibiotic recalcitrance in alginate-encapsulated P. aeruginosa strains isolated from cystic fibrosis patients in the presence of amikacin, tobramycin, and ciprofloxacin. Also, expression of an efflux pump gene, mexY, was analyzed in selected strains in the presence of amikacin and ferrous.

METHODS: Clinical P. aeruginosa strains were isolated from cystic fibrosis patients and minimum inhibitory concentration of amikacin, tobramycin, and ciprofloxacin was determined against all the strains. For each antibiotic, a susceptible and a resistant or an intermediate-resistant strain were selected, encapsulated into alginate beads, and subjected to minimal biofilm eradication concentration (MBEC) test. After determining MBECs, sub-MBEC concentrations (antibiotics at concentrations one level below the determined MBEC) for each antibiotic were selected and used to study the effects of nitrate, arginine, and ferrous on antibiotic recalcitrance of encapsulated strains. Effects of ferrous and amikacin on expression of the efflux pump gene, mexY, was studied on amikacin sensitive and intermediate-resistant strains. One-way ANOVA and t test were used as the statistical tests.

RESULTS: According to the results, the supplements had a dose-related effect on decreasing the number of viable cells; maximal effect was noted with ferrous, as ferrous supplementation significantly increased biofilm susceptibility to both ciprofloxacin and amikacin in all strains, and to tobramycin in a resistant strain. Also, treating an amikacin-intermediate strain with amikacin increased the expression of mexY gene, which has a role in P. aeruginosa antibiotic recalcitrance, while treating the same strain with ferrous and amikacin significantly decreased the expression of mexY gene, which was a promising result.

CONCLUSIONS: Our results support the possibility of using ferrous and arginine as an adjuvant to enhance the efficacy of conventional antimicrobial therapy of P. aeruginosa infections.}, } @article {pmid37470308, year = {2023}, author = {Al-Mutalib, LAA and Zgair, AK}, title = {Effect of subinhibitory doses of rifaximin on in vitro Pseudomonas aeruginosa adherence and biofilm formation to biotic and abiotic surface models.}, journal = {Polimery w medycynie}, volume = {}, number = {}, pages = {}, doi = {10.17219/pim/166584}, pmid = {37470308}, issn = {0370-0747}, abstract = {BACKGROUND: The adhesion of Pseudomonas aeruginosa to biotic and abiotic surfaces is responsible for the persistence and development of bacterial infection.

OBJECTIVES: To fill the gap in the knowledge regarding the relationship between rifaximin susceptibility and biofilm formation, and to investigate the effect of subinhibitory doses of rifaximin on the adhesion and biofilm formation.

MATERIAL AND METHODS: A total of 10 isolates of P. aeruginosa were obtained from 110 urine samples of urinary tract infection (UTI) patients. Biofilm formation on polystyrene microtiter plates, minimum inhibitory concentrations (MICs) of rifaximin against the 10 isolates of P. aeruginosa (Pa1-Pa10), the effect of sub-MICs of rifaximin (0.5 × MIC, 0.25 × MIC, 0.125 × MIC, and 0.06 × MIC) on biofilm formation by the Pa4 isolate to polystyrene microtiter plates, and the adhesion to human epithelial cells (HECs) in vitro were evaluated.

RESULTS: The MICs of rifaximin against 10 isolates ranged from 62.5 μg/mL to 1000 μg/mL. The Pa4 isolate produced the highest level of biofilm formation, while the MIC of Pa4 was 125 μg/mL. There was no correlation between bacterial susceptibility to rifaximin and biofilm formation (r: -0.016; p > 0.05). Sub-MIC doses of rifaximin significantly reduced the biofilm formation on abiotic surfaces, while only 0.5 × MIC, 0.25 × MIC and 0.12 × MIC of rifaximin reduced the adhesion to HECs significantly (p < 0.05) in a dose-dependent manner.

CONCLUSIONS: This pioneering study demonstrated the negative effect of sub-MIC doses of rifaximin on biofilm formation and adhesion to abiotic and biotic surfaces in vitro.}, } @article {pmid37470303, year = {2023}, author = {Blochberger, BL and Symmank, J and Nitzsche, Á and Nietzsche, S and Steiniger, F and Guellmar, A and Reise, M and Sigusch, B and Jacobs, C and Hennig, CL}, title = {Influence of the orthodontic bonding procedure on biofilm formation.}, journal = {Orthodontics & craniofacial research}, volume = {}, number = {}, pages = {}, doi = {10.1111/ocr.12692}, pmid = {37470303}, issn = {1601-6343}, abstract = {INTRODUCTION: In orthodontics, white spot lesions are a persistent and widespread problem caused by the demineralization of buccal tooth surfaces around bonded brackets. The remaining adhesive around the brackets leads to surface roughness, which might contribute to demineralization. The present in vitro study aimed to compare a conventional and a modern adhesive system (APC Flash-Free technology) for orthodontic brackets with regard to the adhesion of Streptococcus sobrinus, a leading caries pathogen.

METHODS: This in vitro study included 20 premolar teeth and compared 10 APC Flash-Free adhesive-coated ceramic brackets (FF)with 10 conventionally bonded (CB) ceramic clarity brackets. Specimens were incubated in an S. sobrinus suspension for 3 h. To evaluate the bacterial formation, samples were analysed with a scanning electron microscope (SEM). Imaging software was used to quantify and statistically compare percentage values of colonization (PVC) in both groups' adhesion and transition areas.

RESULTS: We found a significant difference in biofilm formation between the groups for the adhesive and transition areas. PVC in the adhesive area was approximately 10.3-fold greater for the CB group compared with the FF group (median: 3.2 vs 0.31; P < 0.0001). For the transition area, median PVC was approximately 2.4-fold greater for the CB group compared with the FF group (median: 53.17 vs 22.11; P < 0.01).

CONCLUSIONS: There was a significantly lower level of S. sobrinus formation around the FF bracket system than there was surrounding the conventionally bonded group. This study suggests that the FF adhesive bracket system can help reduce the occurrence of bacterial growth around orthodontic brackets.}, } @article {pmid37469250, year = {2023}, author = {Ichioka, Y and Virto, L and Nuevo, P and Gamonal, JD and Derks, J and Larsson, L and Sanz, M and Berglundh, T}, title = {Decontamination of biofilm-contaminated implant surfaces: An in vitro evaluation.}, journal = {Clinical oral implants research}, volume = {}, number = {}, pages = {}, doi = {10.1111/clr.14136}, pmid = {37469250}, issn = {1600-0501}, support = {//Patentmedelsfonden/ ; //TUA research funding/ ; }, abstract = {OBJECTIVES: The aim of the present study was to evaluate the cleaning efficacy of two mechanical and two chemical protocols in the decontamination of implant surfaces.

METHODS: In total, 123 commercially available implants were mounted in plastic models mimicking peri-implant circumferential intra-bony defects. A multispecies biofilm was grown on implant surfaces. Mechanical (air-polishing (AP), rotating titanium brush (TiB)) and chemical decontamination (alkaline electrolyzed water, N-acetyl-L-cysteine) protocols were used. Cleaning efficacy in terms of residual biofilm area, chemical surface properties, and bacterial counts were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and quantitative polymerase chain reaction.

RESULTS: Surface decontamination protocols including use of an AP device or a rotating TiB were superior in terms of biofilm removal and in reducing atomic% of Carbon on implant surfaces when compared to methods restricted to wiping with gauze. The use of chemical agents as adjuncts to the mechanical cleaning protocols provided no relevant overall benefit over saline. No treatment modality, however, resulted in complete biofilm removal.

CONCLUSION: Air-polishing and rotating TiB were more effective implant surface decontamination protocols than wiping with gauzes. Use of chemical agents did not improve cleaning efficacy.}, } @article {pmid37468003, year = {2023}, author = {Wang, X and Hou, H and Liu, P and Hou, L and Yang, T and Dai, H and Li, J}, title = {Acceleration of nitrogen removal performance in a biofilm reactor augmented with Pseudomonas sp. using polycaprolactone as carbon source for treating low carbon to nitrogen wastewater.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129507}, doi = {10.1016/j.biortech.2023.129507}, pmid = {37468003}, issn = {1873-2976}, abstract = {Heterotrophic nitrification-aerobic denitrification (HN-AD) process was achieved in a moving bed biofilm reactor after 180-days acclimation using PCL as carbon source for low C/N wastewater treatment. A novel HN-AD strain, JQ-H3, with ability of PCL degradation was augmented to improve nitrogen removal. TN removal efficiencies of 82.31%, 90.05%, and 93.16% were achieved in the augmented reactor (R2), at different HRTs of 24 h, 20 h, and 16 h, while in the control reactor (R1), the TN removal efficiencies were 59.24%, 74.61%, and 76.68%. The effluent COD in R2 was 10.17 mg/L, much lower than that of 42.45 mg/L in R1. Microbial community analysis revealed that JQ-H3 has successfully proliferated with a relative abundance of 4.79%. Relative abundances of functional enzymes of nitrogen cycling remarkably increased due to bioaugmentation based on the analysis of PICRUSt2. This study provides a new approach for enhancing nitrogen removal in low C/N sewage treatment via the HN-AD process.}, } @article {pmid37468600, year = {2023}, author = {Sushmitha, TJ and Rajeev, M and Kathirkaman, V and Shivam, S and Rao, TS and Pandian, SK}, title = {3-Hydroxy coumarin demonstrates anti-biofilm and anti-hyphal efficacy against Candida albicans via inhibition of cell-adhesion, morphogenesis, and virulent genes regulation.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {11687}, pmid = {37468600}, issn = {2045-2322}, support = {51/14/06/2019-BRNS//Board of Research in Nuclear Sciences/ ; }, abstract = {Candida albicans, a common fungus of human flora, can become an opportunistic pathogen and causes invasive candidiasis in immunocompromised individuals. Biofilm formation is the prime cause of antibiotic resistance during C. albicans infections and treating biofilm-forming cells is challenging due to their intractable and persistent nature. The study intends to explore the therapeutic potential of naturally produced compounds by competitive marine bacteria residing in marine biofilms against C. albicans biofilm. To this end, 3-hydroxy coumarin (3HC), a compound identified from the cell-free culture supernatant of the marine bacterium Brevundimonas abyssalis, was found to exhibit anti-biofilm and anti-hyphal activity against both reference and clinical isolates of C. albicans. The compound demonstrated significant inhibitory effects on biofilms and impaired the yeast-to-hyphal transition, wrinkle, and filament morphology at the minimal biofilm inhibitory concentration (MBIC) of 250 µg mL[-1]. Intriguingly, quantitative PCR analysis of 3HC-treated C. albicans biofilm revealed significant downregulation of virulence genes (hst7, ume6, efg1, cph1, ras1, als1) associated with adhesion and morphogenesis. Moreover, 3HC displayed non-fungicidal and non-toxic characteristics against human erythrocytes and buccal cells. In conclusion, this study showed that marine biofilms are a hidden source of diverse therapeutic drugs, and 3HC could be a potent drug to treat C. albicans infections.}, } @article {pmid37468524, year = {2023}, author = {Angelini, LL and Dos Santos, RAC and Fox, G and Paruthiyil, S and Gozzi, K and Shemesh, M and Chai, Y}, title = {Pulcherrimin protects Bacillus subtilis against oxidative stress during biofilm development.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {50}, pmid = {37468524}, issn = {2055-5008}, support = {1651732//National Science Foundation (NSF)/ ; }, abstract = {Pulcherrimin is an iron-binding reddish pigment produced by various bacterial and yeast species. In the soil bacterium Bacillus subtilis, this pigment is synthesized intracellularly as the colorless pulcherriminic acid by using two molecules of tRNA-charged leucine as the substrate; pulcherriminic acid molecules are then secreted and bind to ferric iron extracellularly to form the red-colored pigment pulcherrimin. The biological importance of pulcherrimin is not well understood. A previous study showed that secretion of pulcherrimin caused iron depletion in the surroundings and growth arrest on cells located at the edge of a B. subtilis colony biofilm. In this study, we identified that pulcherrimin is primarily produced under biofilm conditions and provides protection to cells in the biofilm against oxidative stress. We presented molecular evidence on how pulcherrimin lowers the level of reactive oxygen species (ROS) and alleviates oxidative stress and DNA damage caused by ROS accumulation in a mature biofilm. We also performed global transcriptome profiling to identify differentially expressed genes in the pulcherrimin-deficient mutant compared with the wild type, and further characterized the regulation of genes by pulcherrimin that are related to iron homeostasis, DNA damage response (DDR), and oxidative stress response. Based on our findings, we propose pulcherrimin as an important antioxidant that modulates B. subtilis biofilm development.}, } @article {pmid37468451, year = {2023}, author = {Khan, NA and Barthes, N and McCormack, G and O'Gara, JP and Thomas, OP and Boyd, A}, title = {Sponge-derived fatty acids inhibit biofilm formation of MRSA and MSSA by down-regulating biofilm-related genes specific to each pathogen.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad152}, pmid = {37468451}, issn = {1365-2672}, abstract = {AIM: A promising approach for the development of next generation antimicrobials is to shift their target from causing bacterial death to inhibiting virulence. Marine sponges are an excellent potential source of bioactive anti-virulence molecules (AVM). We screened fractions prepared from 26 samples of Irish coastal sponges for anti-biofilm activity against clinically relevant pathogens.

METHODS AND RESULTS: Fifteen fractions from eight sponge species inhibited biofilm of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and/or Listeria monocytogenes without causing growth inhibition. GC-MS analyses of Mycale contarenii fractions revealed the presence of myristic acid and oleic acid. These fatty acids repressed transcription of the fibronectin-binding protein fnbA and fnbB genes and the polysaccharide intercellular adhesin icaADBC operon, required for MRSA and MSSA biofilm formation, respectively.

CONCLUSIONS: This study illustrates the potential of AVM from Irish coastal sponges to specifically target bacterial virulence phenotypes, in this case repression of biofilm formation via decreased transcription of biofilm-associated genes in MSSA and MRSA.}, } @article {pmid37466551, year = {2023}, author = {Nunes, TSBS and Silva, MDDD and Coelho, SRG and Viotto, HEDC and Pero, AC}, title = {Effectiveness of disinfectant solutions associated or not with brushing on the biofilm control of a 3D printed-denture base resin.}, journal = {Journal of applied oral science : revista FOB}, volume = {31}, number = {}, pages = {e20230104}, doi = {10.1590/1678-7757-2023-0104}, pmid = {37466551}, issn = {1678-7765}, abstract = {BACKGROUND: The formation of biofilm on denture bases is a recurrent clinical problem that favors the development of denture stomatitis. The effectiveness of a hygiene protocol in a 3D-printed denture base resin is still uncertain.

OBJECTIVE: To evaluate of the effectiveness of immersion, associated or not with brushing in a soap solution, on the biofilm control of a 3D-printed denture base resin.

METHODOLOGY: Specimens of denture base resins [Cosmos Denture (COS) and Classico (CLA/control)] were contaminated in vitro with Candida albicans and immersed in sodium hypochlorite 0.25% (SH, alkaline peroxide) AP, chlorhexidine digluconate 2% (CD or PBS-Control), associated or not with brushing with 0.78% Lifebuoy soap. Roughness was evaluated before and after brushing and immersion. The effectiveness of the protocols was assessed by CFU/mL, cellular metabolism (XTT), scanning electron microscopy (SEM), and confocal scanning laser microscopy. Data were analyzed by T student, ANOVA/Welch, and Tukey/Gomes-Howell pos-hoc tests (α = 0.05).

RESULTS: CLA showed greater roughness than COS. CFU/mL and XTT were higher in COS resin with a higher hyphae formation. Immersion in SH and CD eliminated CFU/mL and reduced XTT for both resins, associated or not with brushing. AP reduced CFU/mL only when associated with brushing.

CONCLUSIONS: The biofilm on the 3D-printed resin was thicker and presumably more pathogenic, regardless of its smoother surface. Immersions in SH 0.25% and CD 2% are effective hygiene protocols for both resins, associated or not with brushing. AP should be recommended when associated with brushing with a Lifebuoy 0.78% solution.}, } @article {pmid37466543, year = {2023}, author = {Cruz, KL and Mayer, FQ and Morales, DL and Motta, AS}, title = {Evaluation of the motility and capacity of biofilm production by Pseudomonas fluorescens strains in residual milk.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {95}, number = {suppl 1}, pages = {e20220982}, doi = {10.1590/0001-3765202320220982}, pmid = {37466543}, issn = {1678-2690}, abstract = {Pseudomonas fluorescens is known to have the ability to adhere and produce biofilm. The formation of biofilms is enhanced by cellular motility, particularly when mediated by flagella. Biofilm formed on surfaces such as those used for food production act as points of contamination, releasing pathogenic or deteriorating microorganisms and compromising the quality of products. We assessed two strains of Pseudomonas fluorescens PL5.4 and PL7.1, sampled from raw, chilled, buffalo milk, which was obtained from a dairy farm. Twitching and swarming motility assays were performed, in addition to the biofilm production evaluations at a temperature of 7 °C. Regarding the motility assays, only the PL5.4 strain scored positive for the swarming assay. On microplates, both strains presented themselves as strong biofilm producers at 7 °C. The PL5.4 strain was also able to form biofilm on a stainless steel structure and maintain this structure for up to 72 hours at refrigeration. The Pseudomonas fluorescens PL5.4 isolate was identified on the basis of a 99% sequence identity with Pseudomonas fluorescens A506, a strain used as a biocontrol in agriculture. Biofilm-forming bacteria, when adapted to low temperatures, become a constant source of contamination, damaging the production, quality, safety and shelf-life of products.}, } @article {pmid37466524, year = {2023}, author = {Matoso, FB and Montagner, F and Jardine, AP and Quintana, RM and Grecca, FS and Kopper, PMP}, title = {Effect of different disinfection protocols in bacterial viability of an intraradicular biofilm formed in situ.}, journal = {Brazilian dental journal}, volume = {34}, number = {3}, pages = {42-49}, doi = {10.1590/0103-6440202305244}, pmid = {37466524}, issn = {1806-4760}, abstract = {The present study aimed to evaluate bacterial viability after the use of different disinfection protocols in root canals infected with a multispecies biofilm (MB) formed in situ. Palatal roots with a single canal were obtained from extracted maxillary molars and sterilized before being inserted into the mouth. The roots were contaminated with a MB in an intraoral appliance worn by ten volunteers. All volunteers wore six roots simultaneously in two intraoral devices for 21 days. One root from each volunteer was assigned to each group (n=10): PUI - passive ultrasonic irrigation; EC - Easy Clean; XPF - XP-endo Finisher; aPDT - antimicrobial photodynamic therapy; CI - conventional irrigation; and NC - negative control. The samples were evaluated under confocal laser scanning microscopy. The percentage of viable cells (VC) was calculated over the total percentage of MB biovolume. Data were statistically analyzed (α=5%). The cell viability in the entire root canal or for each third was compared between groups (Kruskal-Wallis test, Dunn post-hoc test) and for the same group (Friedman test, Dunn post-hoc test). Disinfection protocols were not significantly different from each other (P>.05). Samples in EC, PUI, and aPDT had lower cell viability than in NC (P<.05). In the coronal third of samples in the EC, XPF, PUI and aPDT, the percentage of VC biovolume was lower than in the NC (P<.05). The percentage of VC in EC samples was lower in the coronal and middle thirds than in the apical third (P<.05). EC, PUI and aPDT had significant effects on cell viability in intraradicular multispecies biofilm formed in situ when compared with untreated samples.}, } @article {pmid37466523, year = {2023}, author = {Merçon, IR and Campos, FUF and Fontana, CE and Pelegrine, RA and Martin, AS and Bueno, CEDS}, title = {Analysis of antimicrobial efficacy of sodium hypochlorite and ozonated water against biofilm in oval canals.}, journal = {Brazilian dental journal}, volume = {34}, number = {3}, pages = {33-41}, doi = {10.1590/0103-6440202305318}, pmid = {37466523}, issn = {1806-4760}, abstract = {This in vitro study compared the antimicrobial efficacy of 2.5% sodium hypochlorite (NaOCl) and 8 µg/mL ozonated water agitated by passive ultrasonic irrigation (PUI) or PUI combined with EndoActivator (EA) against mature multispecies biofilm. One hundred and five oval-shaped mandibular premolars were instrumented, sterilized, and inoculated with Enterococcus faecalis, Candida albicans, and Staphylococcus aureus, divided into: control group - saline; O3 group - ozonated water; O3 PUI group - ozonated water with PUI agitation; O3 PUI+EA group - ozonated water with PUI+EA agitation; NaOCl group - NaOCl; NaOCl PUI group - NaOCl with PUI agitation; and NaOCl PUI+EA group - NaOCl with PUI+EA agitation. Microbiological samples were collected before (S1) and after (S2) the disinfection procedures and the data were statistically analyzed using the Kruskal-Wallis test. In the culture method, there was significant disinfection in the O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). The combination of NaOCl with PUI+EA reduced microbial counts to zero (p˂0.05). In the qPCR method, there was a significant reduction in the total count of viable microorganisms in the O3 PUI, O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). It can be concluded that 2.5% NaOCl with and without agitation, as well as 8 µg/mL ozonated water with its action enhanced by the agitation techniques, were effective in root canal disinfection, and their antimicrobial efficacy is related to the microorganisms present in the biofilm.}, } @article {pmid37464169, year = {2023}, author = {Celebi, O and Celebi, D and Baser, S and Aydın, E and Rakıcı, E and Uğraş, S and Ağyar Yoldaş, P and Baygutalp, NK and El-Aty, AMA}, title = {Antibacterial Activity of Boron Compounds Against Biofilm-Forming Pathogens.}, journal = {Biological trace element research}, volume = {}, number = {}, pages = {}, pmid = {37464169}, issn = {1559-0720}, abstract = {This study aimed to evaluate the antibacterial activity of nine boron derivatives against biofilm-forming pathogenic bacteria. The effect of boron derivatives (CMB, calcium metaborate; SMTB, sodium metaborate tetrahydrate; ZB, zinc borate; STFB, sodium tetra fluorine borate; STB, sodium tetraborate; PTFB, potassium tetra fluor borate; APTB, ammonium pentabo-rate tetrahydrate; SPM, sodium perborate monohydrate; Borax, ATFB, ammonium tetra fluorine borate) on bacteria isolated from blood culture was determined by the minimum inhibitory concentration (MIC) method. Then, biofilm formation potentials on microplates, tubes, and Congo red agar were examined. The cytotoxicity of boron derivatives was determined by using WST-1-based methods. The interaction between the biofilm-forming bacteria, fibroblast cells, and boron derivatives was determined with the infection model. We found that the sodium metaborate tetrahydrate molecule was effective against all pathogens. According to the optical density values detected at 630 nm in microplates, meticillin-resistant Staphylococcus aureus was observed to have the most substantial biofilm ability at 0.257 nm. As a result of cytotoxicity studies, it has been determined that a 1 µg/L concentration of boron derivatives is not toxic to fibroblast L929 cells. In cell culture experiments, these boron derivatives have very serious inhibitory activity against biofilm-forming pathogens in a short treatment period, such as 2-4 h. Furthermore, using these molecules on inanimate surfaces affected by biofilms would be appropriate instead of living cells.}, } @article {pmid37462621, year = {2023}, author = {Thornton, JM and Padovani, CM and Rodriguez, A and Spur, BW and Yin, K}, title = {Lipoxin A4 promotes antibiotic and monocyte bacterial killing in established Pseudomonas aeruginosa biofilm formed under hydrodynamic conditions.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {37}, number = {8}, pages = {e23098}, doi = {10.1096/fj.202300619R}, pmid = {37462621}, issn = {1530-6860}, support = {RO1 AI128202//HHS | NIH | NIAID |/ ; }, abstract = {Pseudomonas aeruginosa is a gram-negative, opportunistic bacteria commonly found in wounds and in lungs of immunocompromised patients. These bacteria commonly form biofilms which encapsulate the bacteria, making it difficult for antibiotics or immune cells to reach the bacterial cells. We previously reported that Lipoxin A4 (LxA4), a Specialized Pro-resolving Mediator, has direct effects on P. aeruginosa where it reduced biofilm formation and promoted ciprofloxacin antibiotic efficacy in a static biofilm-forming system. In the current studies, we examined the actions of LxA4 on established biofilms formed in a biofilm reactor under dynamic conditions with constant flow and shear stress. These conditions allow for biofilm growth with nutrient replenishment and for examination of bacteria within the biofilm structure. We show that LxA4 helped ciprofloxacin reduction of live/dead ratio of bacteria within the biofilm. THP-1 monocytes interacted with the biofilm to increase the number of viable bacteria within the biofilm as well as TNF-α production in the biofilm milieu, suggesting that monocyte interaction with bacterial biofilm exacerbates the inflammatory state. Pre-treatment of the THP-1 monocytes with LxA4 abolished the increase in biofilm bacteria and reduced TNF-α production. The effect of decreased biofilm bacteria was associated with increased LxA4 -induced monocyte adherence to biofilm but not increased bacteria killing suggesting that the mechanism for the reduced biofilm bacteria was due to LxA4 -mediated increase in adherence to biofilm. These results suggest that LxA4 can help antibiotic efficacy and promote monocyte activity against established P. aeruginosa biofilm formed under hydrodynamic conditions.}, } @article {pmid37462451, year = {2023}, author = {Sturabotti, E and Moldoveanu, VG and Camilli, A and Martinelli, A and Simonetti, G and Valletta, A and Serangeli, I and Giustini, A and Miranda, E and Migneco, LM and Vetica, F and Leonelli, F}, title = {Thymol-Functionalized Hyaluronic Acid as Promising Preservative Biomaterial for the Inhibition of Candida albicans Biofilm Formation.}, journal = {ACS macro letters}, volume = {}, number = {}, pages = {1079-1084}, doi = {10.1021/acsmacrolett.3c00208}, pmid = {37462451}, issn = {2161-1653}, abstract = {Hyaluronic acid (HA) is a naturally occurring biopolymer that has been employed for a plethora of medicinal applications. Nevertheless, as HA is a natural polysaccharide, it can be a substrate able to promote microbial growth and proliferation. Biopolymer-drug conjugates have gained attention over the years to overcome drawbacks of each single component. Within this context, thymol (Thy), a phenolic compound occurring in essential oils (EOs) extracted from Thymus and Origanum, has been largely studied for its antimycotic applications. However, it is characterized by a low water solubility and moderate cytotoxicity. Herein, we report an innovative HA-thymol conjugate (HA-Thy) biomaterial to circumvent the drawbacks of free thymol use by providing the polymer conjugate with the beneficial properties of both components. Preliminary biological tests evidenced the decrease of thymol cytotoxicity for the HA-Thy conjugate, paired with a promising antibiofilm formation activity against Candida albicans, similar to pure thymol, highlighting its potential application as a preservative biomaterial in formulations.}, } @article {pmid37462306, year = {2023}, author = {Ergin, Ç and Öner, SZ and Özkan, B and Onaç, C and Gümral, R and Okul, M and Şengül, M}, title = {[Evaluation of Malassezia furfur Biofilm Formation on Polypropylene Membrane].}, journal = {Mikrobiyoloji bulteni}, volume = {57}, number = {3}, pages = {432-443}, doi = {10.5578/mb.20239935}, pmid = {37462306}, issn = {0374-9096}, abstract = {The Malassezia yeast species colonize on the skin immediately after birth and could be found on the healthy skin flora for life. Although they are more frequently involved in the etiology of common skin infections in the community, particularly Malassezia furfur could cause life-threatening infections such as fungemia. Detection of biofilm during the colonization of these yeasts on the skin is an important criterion for its virulence. Since they are lipophilic yeasts, commonly used biofilm detection methods are not applicable to the Malassezia strains. The aim of the study was to describe the growth and measurement of M.furfur isolates on a polypropylene membrane to demonstrate their biofilm-forming capacities. Twenty-seven M.furfur strains colonized in the newborns were included in the study. Basically, sterile polypropylene membranes were placed on different polysorbates (tween 20, 40, and 80) which were spread on Sabouraud dextrose agar. Ten µl saline suspension of M.furfur was dropped on the polypropylene membrane and incubated in standard growth conditions for three days. Later, the visible colony was removed gently by washing with running water and the biofilm structure formed on the membrane was stained with safranin. The stained biofilm was photographed. Performing image analysis, the values obtained against background activity were digitized according to the specified protocol. Moreover, XTT reduction test was performed and the measured metabolic activity results were compared with the safranin-stained biofilm data. The safranin hydrolysis of the strains was measured spectrometrically. Twenty-five (92.6%) of the strains included in the study were stained with safranin, which indicated the presence of biofilm on the polypropylene membrane. The strains grown with tween 20 and tween 80 formed a higher biofilm layer density than those supplied with tween 40. Isolates with low and high biofilm-forming capacity were clearly separated by tween 20 (p< 0.05). XTT activity was detected in 26 (96.3%) isolates. No correlation was found between biofilm density obtained by the described method and XTT reduction. It was observed that hydrolysis of safranin did not affect the biofilm evaluation method. In this study, it was shown that as a result of sufficient diffusion through hydrophobic membranes, polysorbate-based growth factors could maintain measurement of the biofilm layer formed by lipophilic M.furfur strains. The best grouping properties for M.furfur were obtained with tween 20 which could determine low and high level of biofilm formation. Image analysis was used with high performance for this method. As conclusion, the utilization of different hydrophobic membranes and dyes would lead to the development of new techniques for the application in other lipophilic yeasts.}, } @article {pmid37460611, year = {2023}, author = {Werneburg, GT and Lundy, SD and Hettel, D and Bajic, P and Gill, BC and Adler, A and Mukherjee, SD and Wood, HM and Angermeier, KW and Shoskes, DA and Miller, AW}, title = {Microbe-metabolite interaction networks, antibiotic resistance, and in vitro reconstitution of the penile prosthesis biofilm support a paradigm shift from infection to colonization.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {11522}, pmid = {37460611}, issn = {2045-2322}, abstract = {To understand differences between asymptomatic colonized and infected states of indwelling medical devices, we sought to determine penile prosthesis biofilm composition, microbe-metabolite interaction networks, and association with clinical factors. Patients scheduled for penile prosthesis removal/revision were included. Samples from swabbed devices and controls underwent next-generation sequencing, metabolomics, and culture-based assessments. Biofilm formation from device isolates was reconstituted in a continuous-flow stir tank bioreactor. 93% of 27 analyzed devices harbored demonstrable biofilm. Seven genera including Faecalibaculum and Jeotgalicoccus were more abundant in infected than uninfected device biofilms (p < 0.001). Smokers and those with diabetes mellitus or cardiac disease had lower total normalized microbial counts than those without the conditions (p < 0.001). We identified microbe-metabolite interaction networks enriched in devices explanted for infection and pain. Biofilm formation was recapitulated on medical device materials including silicone, PTFE, polyurethane, and titanium in vitro to facilitate further mechanistic studies. Nearly all penile prosthesis devices harbor biofilms. Staphylococcus and Escherichia, the most common causative organisms of prosthesis infection, had similar abundance irrespective of infection status. A series of other uncommon genera and metabolites were differentially abundant, suggesting a complex microbe-metabolite pattern-rather than a single organism-is responsible for the transition from asymptomatic to infected or painful states.}, } @article {pmid37459835, year = {2023}, author = {Núñez, P and Misic, C and Cutroneo, L and Capello, M and Medina, R and Besio, G}, title = {Biofilm-induced effect on the buoyancy of plastic debris: An experimental study.}, journal = {Marine pollution bulletin}, volume = {193}, number = {}, pages = {115239}, doi = {10.1016/j.marpolbul.2023.115239}, pmid = {37459835}, issn = {1879-3363}, abstract = {Plastic floating on the ocean surface represents about 1 % of all plastic in the ocean, despite the buoyancy of most plastics. Biofouling can help to sink debris, which could explain this discrepancy. A set of laboratory experiments was conducted to investigate biofilm-induced effects on the buoyancy of different plastic debris. Ten materials of different densities (buoyant/non-buoyant), sizes (micro/meso/macro), and shapes (irregular/spherical/cylindrical/flat), including facemasks and cotton swabs, were evaluated. Biofilm was incubated in these materials from a few weeks to three months to investigate the effect of different growth levels on their buoyancy. Biofilm levels and rising/settling velocities were measured and compared at seven time-points. The results show a hindered buoyancy for solid materials, while hollow and open materials showed the opposite trend in early biofilm colonization stages. A relationship was established between biofilm-growth and equivalent sphere diameter that can be used to improve predictive modeling of plastic-debris transport.}, } @article {pmid37459810, year = {2023}, author = {Yang, B and Liu, Q and Liu, Y and Huang, T and Zhao, Y and Li, D and Pan, X}, title = {Biofilm-developed biomass residues as novel bulking agents and microbial carriers for synergistically enhanced bioevaporation: Degradation potential and contribution to metabolic heat.}, journal = {Journal of environmental management}, volume = {344}, number = {}, pages = {118570}, doi = {10.1016/j.jenvman.2023.118570}, pmid = {37459810}, issn = {1095-8630}, abstract = {Economical and easily prepared bulking agents and microbial carriers are essential in the practical application of bioevaporation process. Biofilm-developed biomass residues not only provide structural support and microbial sources but also may contribute metabolic heat to the bioevaporation process, achieving the enhanced water evaporation and synergistic treatment of biomass residues. In this study, biofilm was cultivated on the rice straw, wheat straw, sawdust, corncob, luffa cylindrica and palm first, then those biofilm-developed biomass residues were successfully used as the bulking agents and microbial carriers in food waste bioevaporation. The degradation potential (volatile solid degradation ratio) of those biomass residues was in the order of corncob (23.96%), wheat straw (21.12%), rice straw (14.57%), luffa cylindrica (11.02%), sawdust (-2.87%) and palm (-9.24%). It's primarily the degradation of the major components, cellulose and hemicellulose, in corncob and wheat straw governed the metabolic heat contribution (91.73 and 79.61%) to the bioevaporation process. While the high lignin content in sawdust (14.57%) and palm (28.62%) caused negligible degradation of cellulose and hemicellulose, hence made them only function as structural supporter and did not contribute any metabolic heat. Moreover, though the metabolic heat contribution of rice straw and luffa cylindrica reached 58.19 and 37.84%, their lowest lignocellulose content (62.99 and 65.95%) and their lower density, as well as the dominated Xanthomonas (bacteria) and Mycothermus (fungi) led to their rapid collapse during the repeated cycles of bioevaporation. The greatest abundance of thermophilic bacteria (22.3-88.0%) and thermophilic fungi (82.0-99.3%) was observed in the corncob pile. Furthermore, considering the Staphylococcus (pathogenic bacteria) and Candida (animal pathogen) was effectively inhibited, the biofilm-developed corncob was the most favorable bulking agents and microbial carrier for the synergistic bioevaporation of highly concentrated organic wastewater and biomass residues.}, } @article {pmid37458689, year = {2023}, author = {Guo, W and Liu, Y and Yao, Z and Zhou, H and Wang, X and Huang, Z and Zhang, X and Wu, Q and Zhou, T}, title = {Bithionol Restores Sensitivity of Multidrug-Resistant Gram-Negative Bacteria to Colistin with Antimicrobial and Anti-biofilm Effects.}, journal = {ACS infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsinfecdis.3c00257}, pmid = {37458689}, issn = {2373-8227}, abstract = {Being among the few last-resort antibiotics, colistin (COL) has been used to treat severe infectious diseases, such as those caused by multidrug-resistant Gram-negative bacteria (MDR GNB). However, the appearance of colistin-resistant (COL-R) GNB has been frequently reported. Therefore, novel antimicrobial strategies need to be urgently sought to address this resistance challenge. In the present study, antimicrobial drug screening conducted revealed that bithionol (BT), approved by the Food and Drug Administration and used as an anthelminthic drug for paragonimiasis, exhibited a synergistic antibacterial effect with COL. Clinically isolated COL-R GNB were used as candidates to evaluate the synergistic antibacterial activity. The results revealed that BT could significantly reverse the sensitivity of COL-R GNB to COL. Furthermore, the combined application of BT and COL can reduce bacterial biofilm formation and have a scavenging effect on the mature biofilm in vitro. The damage caused to the bacterial cell membrane integrity by the BT/COL combination was observed under a fluorescence microscope. The fluorescence intensity of reactive oxygen species also increased in the experimental group. The BT/COL combination also exhibited a synergistic antibacterial effect in vivo. Importantly, BT was confirmed to be safe at the highest concentrations that exerted synergistic effects on all tested strains. In conclusion, our findings demonstrated that BT exerted synergistic antimicrobial and anti-biofilm effects when combined with COL against MDR organisms, especially COL-R GNB, in vitro and in vivo. The findings thus provide a reference for the clinical response to the serious challenge of MDR GNB and the exploitation of the potential antibacterial activities of existing clinical non-antibacterial drugs.}, } @article {pmid37458592, year = {2023}, author = {Tan, Y and Liu, W and Chen, Y and Zhou, Y and Song, K and Cao, S and Zhang, Y and Song, Y and Deng, H and Yang, R and Du, Z}, title = {Comparative Lysine Acetylome Analysis of Y. pestis YfiQ/CobB Mutants Reveals that Acetylation of SlyA Lys73 Significantly Promotes Biofilm Formation of Y. pestis.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0046023}, doi = {10.1128/spectrum.00460-23}, pmid = {37458592}, issn = {2165-0497}, abstract = {Increasing evidence shows that protein lysine acetylation is involved in almost every aspect of cellular physiology in bacteria. Yersinia pestis is a flea-borne pathogen responsible for millions of human deaths in three global pandemics. However, the functional role of lysine acetylation in this pathogen remains unclear. Here, we found more acetylated proteins and a higher degree of acetylation in Y. pestis grown under mammalian host (Mh) conditions than under flea vector (Fv) conditions, suggesting that protein acetylation could significantly change during fleabite transmission. Comparative acetylome analysis of mutants of YfiQ and CobB, the major acetyltransferase and deacetylase of Y. pestis, respectively, identified 23 YfiQ-dependent and 315 CobB-dependent acetylated proteins. Further results demonstrated that acetylation of Lys73 of the SlyA protein, a MarR-family transcriptional regulator, inhibits its binding to the promoter of target genes, including hmsT that encodes diguanylate cyclase responsible for the synthesis of c-di-GMP, and significantly enhances biofilm formation of Y. pestis. Our study presents the first extensive acetylome data of Y. pestis and a critical resource for the functional study of lysine acetylation in this pathogen. IMPORTANCE Yersinia pestis is the etiological agent of plague, historically responsible for three global pandemics. The 2017 plague epidemic in Madagascar was a reminder that Y. pestis remains a real threat in many parts of the world. Plague is a zoonotic disease that primarily infects rodents via fleabite, and transmission of Y. pestis from infected fleas to mammals requires rapid adaptive responses to adverse host environments to establish infection. Our study provides the first global profiling of lysine acetylation derived from mass spectrometry analysis in Y. pestis. Our data set can serve as a critical resource for the functional study of lysine acetylation in Y. pestis and provides new molecular insight into the physiological role of lysine acetylation in proteins. More importantly, we found that acetylation of Lys73 of SlyA significantly promotes biofilm formation of Y. pestis, indicating that bacteria can use lysine acetylation to fine-tune the expression of genes to improve adaptation.}, } @article {pmid37456062, year = {2023}, author = {Chung, PY and Loh, PLN and Neoh, HM and Ramli, R}, title = {Alpha-amyrin as an anti-biofilm agent against methicillin-resistant and vancomycin-intermediate Staphylococcus aureus.}, journal = {Heliyon}, volume = {9}, number = {7}, pages = {e17892}, pmid = {37456062}, issn = {2405-8440}, abstract = {Staphylococcus aureus has caused life-threatening infections and developed resistance against conventional antimicrobials, posing a significant threat to human health worldwide. Biofilms that surround the bacteria cells act as a protective layer, allowing cells inside the biofilm to be resistant to external stresses such as antimicrobials. Therefore, biofilms further complicate treatment available for infections caused by multi-drug resistant Staphylococcus aureus. A previous study on alpha-amyrin (AM), derived from ursane, was reported to significantly reduce the biomass and inhibit the metabolic activity of reference strain methicillin-resistant and methicillin-sensitive S. aureus (MRSA and MSSA, respectively). In this study, the antibiofilm activity of AM was extended to include clinical isolates of MSSA and MRSA, and laboratory-generated vancomycin-intermediate S. aureus (VISA) collected from University Kebangsaan Malaysia Medical Center (PPUKM) and Universiti Kebangsaan Malaysia Medical Molecular Biology Institute (UMBI). Pre-formed biofilms of biofilm-forming isolates identified from the Congo Red Agar (CRA) assay were then exposed to AM, vancomycin and oxacillin, and evaluated using the crystal violet and resazurin assays. The results showed that AM reduced the biofilm biomass of three isolates of MSSA, eight isolates of MRSA and four isolates of VISA but increased the metabolic activity in certain MSSA, MRSA and VISA isolates, indicating AM may possess biofilm reduction effects but not bactericidal effects. Based on these findings, AM could be further studied and developed as a potential therapeutic agent for chronic S. aureus infections.}, } @article {pmid37454457, year = {2023}, author = {He, Y and Liu, Y and Li, X and Zhu, T and Liu, Y}, title = {Unveiling the roles of biofilm in reducing N2O emission in a nitrifying integrated fixed-film activated sludge (IFAS) system.}, journal = {Water research}, volume = {243}, number = {}, pages = {120326}, doi = {10.1016/j.watres.2023.120326}, pmid = {37454457}, issn = {1879-2448}, abstract = {Biofilm process such as integrated fixed-film activated sludge (IFAS) system has been preliminarily found to produce less nitrous oxide (N2O) than suspended sludge system. However, the N2O emission behaviors and underlying N2O mitigation mechanism in such hybrid system remain unclear. This study therefore aims to fully unveil the roles of biofilm in reducing N2O emission in a nitrifying IFAS system with the aid of some advanced technologies such as N2O microsensor and site-preference analysis. It was found that ammonia oxidation occurred mostly in the sludge flocs (˃ 86%) and biofilm could reduce N2O emission by 43.77% in a typical operating cycle. Biofilm not only reduced nitrite accumulation in nitrification process, inhibiting N2O production via nitrifier denitrification pathway, but also served as a N2O sink, promoting the reduction of N2O via endogenous denitrification. As a result, N2O emissions from the IFAS system were 50%-83% lower than those from the solo sludge flocs. Further, more N2O emission was reduced in the presence of biofilm with decreasing the dissolved oxygen level in the range of 0.5-3.0 mg O2/L. Microbial community and key enzyme analyses revealed that biofilm had relatively high microbial diversity and unique enzyme composition, providing a reasonable explanation for the changed contributions of different N2O production pathways and reduced N2O emission.}, } @article {pmid37454336, year = {2023}, author = {Zhang, J and Lv, M and Wang, X and Wu, F and Yao, C and Shen, J and Zhou, N and Sun, B}, title = {An Immunomodulatory Biomimetic Single-Atomic Nanozyme for Biofilm Wound Healing Management.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2302587}, doi = {10.1002/smll.202302587}, pmid = {37454336}, issn = {1613-6829}, support = {BE2020347//Natural Science Foundation of Jiangsu Province/ ; //Jiangsu Engineering Research Center for Biomedical Function Materials/ ; //Jiangsu Key Laboratory of Bio-functional Materials/ ; //Jiangsu Collaborative Innovation Center of Biomedical Functional Materials/ ; }, abstract = {Nanozyme-driven catalytic antibacterial therapy has become a promising modality for bacterial biofilm infections. However, current catalytic therapy of biofilm wounds is severely limited by insufficient catalytic efficiency, excessive inflammation, and deep tissue infection. Drawing from the homing mechanism of natural macrophages, herein, a hollow mesoporous biomimetic single-atomic nanozyme (SAN) is fabricated to actively target inflamed parts, suppress inflammatory factors, and eliminate deeply organized bacteria for enhance biofilm eradication. In the formulation, this biomimetic nanozyme (Co@SAHSs@IL-4@RCM) consists of IL-4-loaded cobalt SANs-embedded hollow sphere encapsulate by RAW 264.7 cell membrane (RCM). Upon accumulation at the infected sites through the specific receptors of RCM, Co@SAHS catalyze the conversion of hydrogen peroxide into hydroxyl radicals and are further amplify by NIR-II photothermal effect and glutathione depletion to permeate and destroy biofilm structure. This behavior subsequently causes the dissociation of RCM shell and the ensuing release of IL-4 that can reprogram macrophages, enabling suppression of oxidative injury and tissue inflammation. The work paves the way to engineer alternative "all-in-one" SANs with an immunomodulatory ability and offers novel insights into the design of bioinspired materials.}, } @article {pmid37452128, year = {2023}, author = {Cai, A and Abdali, Z and Saldanha, DJ and Aminzare, M and Dorval Courchesne, NM}, title = {Endowing textiles with self-repairing ability through the fabrication of composites with a bacterial biofilm.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {11389}, pmid = {37452128}, issn = {2045-2322}, abstract = {To address the increasing environmental footprint of the fast-growing textile industry, self-repairing textile composites have been developed to allow torn or damaged textiles to restore their morphological, mechanical, and functional features. A sustainable way to create these textile composites is to introduce a coating material that is biologically derived, biodegradable, and can be produced through scalable processes. Here, we fabricated self-repairing textile composites by integrating the biofilms of Escherichia coli (E. coli) bacteria into conventional knitted textiles. The major structural protein component in E. coli biofilm is a matrix of curli fibers, which has demonstrated extraordinary abilities to self-assemble into mechanically strong macroscopic structures and self-heal upon contact with water. We demonstrated the integration of biofilm through three simple, fast, and scalable methods: adsorption, doctor blading, and vacuum filtration. We confirmed that the composites were breathable and mechanically strong after the integration, with improved Young's moduli or elongation at break depending on the fabrication method used. Through patching and welding, we showed that after rehydration, the composites made with all three methods effectively healed centimeter-scale defects. Upon observing that the biofilm strongly attached to the textiles by covering the extruding textile fibers from the self-repair failures, we proposed that the strength of the self-repairs relied on both the biofilm's cohesion and the biofilm-textile adhesion. Considering that curli fibers are genetically-tunable, the fabrication of self-repairing curli-expressing biofilm-textile composites opens new venues for industrially manufacturing affordable, durable, and sustainable functional textiles.}, } @article {pmid37451042, year = {2023}, author = {Xu, L and Ivanova, SA and Gu, T}, title = {Mitigation of galvanized steel biocorrosion by Pseudomonas aeruginosa biofilm using a biocide enhanced by trehalase.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {154}, number = {}, pages = {108508}, doi = {10.1016/j.bioelechem.2023.108508}, pmid = {37451042}, issn = {1878-562X}, abstract = {Pseudomonas aeruginosa is a facultative bacterium that is pathogenic. It is ubiquitous in the environment including air handling systems. It causes microbiologically influenced corrosion (MIC) aerobically and anaerobically. In this work, P. aeruginosa was grown as a nitrate reducing bacterium (NRB) in Luria-Bertani medium with KNO3 at 37 °C. Trehalase, an enzyme which plays a crucial role in biofilm formation was found to enhance the treatment of P. aeruginosa biofilm and its MIC against galvanized steel by tetrakis-hydroxymethyl phosphonium sulfate (THPS) green biocide. After a 7-d incubation, 30 ppm (w/w) trehalase reduced sessile cell count by 0.8-log, and it also reduced galvanized steel weight loss by 14%, compared to 2.3-log and 39%, respectively for the 30 ppm THPS treatment. The combination of 30 ppm THPS + 30 ppm trehalase reduced sessile cell count further by 0.1-log and weight loss by 13% compared to using THPS alone. Electrochemical corrosion measurements supported weight loss results. The injection of 20 ppm riboflavin into a 3-d P. aeruginosa broth failed to accelerate the corrosion rate, suggesting that nitrate reducing P. aeruginosa MIC of galvanized steel did not belong to extracellular electron transfer-MIC, because Zn was hydrolyzed after the microbe damaged the passive film.}, } @article {pmid37450444, year = {2023}, author = {Eshima, S and Matsumoto, Y and Kurakado, S and Sugita, T}, title = {Silkworm model of biofilm formation: In vivo evaluation of antimicrobial tolerance of a cross-kingdom dual-species (Escherichia coli and Candida albicans) biofilm on catheter material.}, journal = {PloS one}, volume = {18}, number = {7}, pages = {e0288452}, doi = {10.1371/journal.pone.0288452}, pmid = {37450444}, issn = {1932-6203}, abstract = {Biofilms are formed by microorganisms and their products on the surface of materials such as medical devices. Biofilm formation protects microorganisms from antimicrobial agents. Bacteria and fungi often form dual-species biofilms on the surfaces of medical devices in clinical settings. An experimental system to evaluate in vivo biofilm formation by the pathogenic fungus Candida albicans was established using silkworms inserted with polyurethane fiber (PF), a catheter material. In the present study, we established an in vivo experimental system using silkworms to evaluate the antimicrobial tolerance of Escherichia coli in single- and dual-species biofilms formed on the surface of the PF. The injection of E. coli into the PF-inserted silkworms led to the formation of a biofilm by E. coli on the surface of the PF. E. coli in the biofilm exhibited tolerance to meropenem (MEPM). Furthermore, when E. coli and C. albicans were co-inoculated into the PF-inserted silkworms, a dual-species biofilm formed on the surface of the PF. E. coli in the dual-species biofilm with C. albicans was more tolerant to MEPM than E. coli in the single-species biofilm. These findings suggest the usefulness of an in vivo experimental system using PF-inserted silkworms to investigate the mechanisms of MEPM tolerance in E. coli in single- and dual-species biofilms.}, } @article {pmid37450411, year = {2023}, author = {Ellepola, K and Bhatt, L and Chen, L and Han, C and Jahanbazi, F and Klie, RF and Lagunas Vargas, F and Mao, Y and Novakovsky, K and Sapkota, B and Pesavento, RP}, title = {Nanoceria Aggregate Formulation Promotes Buffer Stability, Cell Clustering, and Reduction of Adherent Biofilm in Streptococcus mutans.}, journal = {ACS biomaterials science & engineering}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsbiomaterials.3c00174}, pmid = {37450411}, issn = {2373-9878}, abstract = {Streptococcus mutans is one of the key etiological factors in tooth-borne biofilm development that leads to dental caries in the presence of fermentable sugars. We previously reported on the ability of acid-stabilized nanoceria (CeO2-NP) produced by the hydrolysis of ceric salts to limit biofilm adherence of S. mutans via non-bactericidal mechanism(s). Herein, we report a chondroitin sulfate A (CSA) formulation (CeO2-NP-CSA) comprising nanoceria aggregates that promotes resistance to bulk precipitation under a range of conditions with retention of the biofilm-inhibiting activity, allowing for a more thorough mechanistic study of its bioactivity. The principal mechanism of reduced in vitro biofilm adherence of S. mutans by CeO2-NP-CSA is the production of nonadherent cell clusters. Additionally, dose-dependent in vitro human cell toxicity studies demonstrated no additional toxicity beyond that of equimolar doses of sodium fluoride, currently utilized in many oral health products. This study represents a unique approach and use of a nanoceria aggregate formulation with implications for promoting oral health and dental caries prevention as an adjunctive treatment.}, } @article {pmid37450215, year = {2023}, author = {Shehabeldine, AM and Al-Askar, AA and AbdElgawad, H and Hagras, FA and Ramadan, AA and Kamel, MR and Ahmed, MA and Atia, KH and Hashem, AH}, title = {Wound Dressing Scaffold with High Anti-biofilm Performance Based on Ciprofloxacin-Loaded Chitosan-Hydrolyzed Starch Nanocomposite: In Vitro and In Vivo Study.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37450215}, issn = {1559-0291}, support = {RSP2023R505//King Saud University/ ; }, abstract = {Today, the search for solutions to reduce wound infection and restore wound receptivity also reduces its side effects which are a difficult problem in medical science research. The greatest options for this purpose are hydrogel dressings since they are compatible with tissue and have an antibacterial effect on wound healing. Chronic wounds represent a significant burden on people and healthcare systems worldwide. Bacteria often enter such skin wounds, causing irritation and complicating the healing process. In addition, bacteria cause infection, which inhibits rejuvenation and the production of collagen. This study is aimed at developing novel chitosan (CS)-hydrolyzed starch nanocomposite (HS/Ch-NC) loaded with ciprofloxacin to enhance its skin retention and wound healing efficacy and anti-biofilm efficacy. Drug-loading on the (HS/Ch-NC) and encapsulation efficiency was 55.2% and 97.2%, respectively. The activity of HS-NC loaded with ciprofloxacin as anti-biofilm activity by 72% and 63% against Enterobacter aerogenes and Pseudomonas aeruginosa, respectively. The obtained (HS/Ch-NC) loaded with ciprofloxacin is a promising candidate for the development of improved bandage materials, as cell viability and proliferation was assessed using an SRB assay with half-maximal inhibitory concentrations (IC50) at 119.1 µg/ml. In vitro scratch wound healing assay revealed significant (p ≤ 0.05) acceleration in wound closure at 24 h enhanced by 56.04% 24-h and 100% 72-h post-exposure to (HS/Ch-NC) loaded ciprofloxacin, compared to the negative control. In vivo skin retention study revealed that (HS/Ch-NC)-loaded ciprofloxacin showed 3.65-fold higher retention, respectively, than ciprofloxacin. Thus, our study assumes that ciprofloxacin-loaded HS-NC is a potential delivery system for enhancing ciprofloxacin skin retention and wound healing activity.}, } @article {pmid37449091, year = {2023}, author = {Crisp, AR and Short, B and Rowan, L and Ramage, G and Rehman, IUR and Short, RD and Williams, C}, title = {Investigating the chemical pathway to the formation of a single biofilm using infrared spectroscopy.}, journal = {Biofilm}, volume = {6}, number = {}, pages = {100141}, doi = {10.1016/j.bioflm.2023.100141}, pmid = {37449091}, issn = {2590-2075}, abstract = {Diagnosing biofilm infections has remained a constant challenge for the last 50 years. Existing diagnostic methods struggle to identify the biofilm phenotype. Moreover, most methods of biofilm analysis destroy the biofilm making the resultant data interpretation difficult. In this study we introduce Fourier Transform Infra-Red (FTIR) spectroscopy as a label-free, non-destructive approach to monitoring biofilm progression. We have utilised FTIR in a novel application to evaluate the chemical composition of bacterial biofilms without disrupting the biofilm architecture. S. epidermidis (RP62A) was grown onto calcium fluoride slides for periods of 30 min-96 h, before semi-drying samples for analysis. We report the discovery of a chemical marker to distinguish between planktonic and biofilm samples. The appearance of new proteins in biofilm samples of varying maturity is exemplified in the spectroscopic data, highlighting the potential of FTIR for identifying the presence and developmental stage of a single biofilm.}, } @article {pmid37448686, year = {2023}, author = {Keyhanian, A and Mohammadimehr, M and Nojoomi, F and Naghoosi, H and Khomartash, MS and Chamanara, M}, title = {Inhibition of bacterial adhesion and anti-biofilm effects of Bacillus cereus and Serratia nematodiphila biosurfactants against Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {3}, pages = {425-432}, doi = {10.18502/ijm.v15i3.12903}, pmid = {37448686}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Biosurfactants are amphiphilic surface-active agents that mainly produced by various microorganisms. In this study, the anti-biofilm and inhibition of bacterial adhesion activities of two bacterial biosurfactants were investigated.

MATERIALS AND METHODS: After extraction and evaluation of Bacillus cereus and Serratia nematodiphila biosurfctants, inhibition of bacterial adhesion and anti-biofilm effects of them on Staphylococcus aureus and Pseudomonas aeruginosa were determined.

RESULTS: On average, the synergistic effect of two bacterial biosurfactants, caused about 60% decrease in adhesion and about 80% decrease in biofilm formation of S. aureus and P. aeruginosa.

CONCLUSION: The results of this study showed that combination of B. cereus and S. nematodiphila biosurfactants would increase the potential of attachment inhibition and biofilm eradication with very low toxicity.}, } @article {pmid37448677, year = {2023}, author = {Al-Kahachi, R and Al-Asadi, S and Ali, ZO and Rampurawala, J}, title = {Effects of genetic and environmental variables on biofilm development dynamics in Achromobacter mucicolens.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {3}, pages = {414-424}, doi = {10.18502/ijm.v15i3.12902}, pmid = {37448677}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The study aimed to investigate whether Achromobacter mucicolens IA strain biofilm formation, which contributes to antibiotic resistance, could be enhanced by readily available nutrient sources like carbohydrates and environmental factors such as pH and NaCl. Additionally, the study aimed to identify any inherent genes that support biofilm formation in this strain, which is an opportunistic pathogen that affects immunocompromised patients and is resistant to many antibiotics.

MATERIALS AND METHODS: Biofilm growth in different carbohydrate, pH, and NaCl concentrated media was measured using crystal violet microtiter assay. All the treatments were subjected to biostatistics analysis for normality, Test of Homogeneity, one way ANOVA analysis. Whole-genome sequencing of our IA strain was conducted to identify various gene sequences.

RESULTS: Biofilm formation was measured at different carbohydrate concentrations, and the optimum biofilm formation was observed at 3M glucose and 0.5M NaCl, while the lowest results were seen at 2M maltose concentration. Whole-genome sequencing identified potential genes involved in biofilm formation, pathogenicity, protein metabolism, flagellar motility, cell wall component synthesis, and a multidrug efflux pump.

CONCLUSION: These findings suggest that biofilm formation is influenced by extrinsic and intrinsic factors, which could aid in the development of effective treatments for resistant infections.}, } @article {pmid37444905, year = {2023}, author = {Vilarrasa, J and Àlvarez, G and Soler-Ollé, A and Gil, J and Nart, J and Blanc, V}, title = {Bacterial Adhesion of TESPSA and Citric Acid on Different Titanium Surfaces Substrate Roughness: An In Vitro Study with a Multispecies Oral Biofilm Model.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {13}, pages = {}, doi = {10.3390/ma16134592}, pmid = {37444905}, issn = {1996-1944}, abstract = {This in vitro study analyzed the influence of substrate roughness on biofilm adhesion and cellular viability over triethoxysilylpropyl succinic anhydride silane (TESPSA)- and citric acid (CA)-coated surfaces at 12 and 24 h, respectively. A multispecies biofilm composed of S. oralis, A. naslundii, V. parvula, F. nucleatum, P. intermedia, P. gingivalis, P. endodontalis and F. alocis was developed over titanium discs grouped depending on their roughness (low, medium, high) and antibacterial coating (low-TESPSA, medium-TESPSA, high-TESPSA, and CA). The biofilm was quantified by means of quantitative polymerase chain reaction (PCR) and viability PCR and assessed through confocal laser scanning microscope (CLSM). Quantitative PCR revealed no significant differences in bacterial adhesion and biofilm mortality. CA was the surface with the lowest bacterial counts and highest mortality at 12 and 24 h, respectively, while high harbored the highest amount of biofilm at 24 h. By CLSM, CA presented significant amounts of dead cells compared to medium-TESPSA and high-TESPSA. A significantly greater volume of dead cells was found at 12 h in low-TESPSA compared to medium-TESPSA, while CA also presented significant amounts of dead cells compared to medium-TESPSA and high-TESPSA. With regard to the live/dead ratio, low-TESPSA presented a significantly higher ratio at 12 h compared to medium-TESPSA and high-TESPSA. Similarly, CA exhibited a significantly higher live/dead ratio compared to medium-TESPSA and high-TESPSA at 12 h. This multispecies in vitro biofilm did not evidence clear antiadhesive and bactericidal differences between surfaces, although a tendency to reduce adhesion and increase antibacterial effect was observed in the low-TESPSA and CA.}, } @article {pmid37444846, year = {2023}, author = {Conforte, JJ and Sousa, CA and da Silva, ACR and Ribeiro, AV and Duque, C and Assunção, WG}, title = {Effect of Enterococcus faecalis Biofilm on Corrosion Kinetics in Titanium Grade 4 Alloys with Different Surface Treatments.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {13}, pages = {}, doi = {10.3390/ma16134532}, pmid = {37444846}, issn = {1996-1944}, support = {2017 11471//Foundation for Research Support of the State of São Paulo/ ; 2017 11471//São Paulo Research Foundation/ ; }, abstract = {E. faecalis has been associated with bacteremia, sepsis, and bacterial endocarditis and peri-implantitis. This microorganism can remain in the alveolus even after extraction of the root remnant. This study aimed to evaluate the corrosion on different surfaces of commercially pure titanium (Ti) grade 4 (Ticp-G4) as a function of the bacterial biofilm effect of Enterococcus faecalis. A total of 57 discs were randomly divided according to their surface finish (n = 19). For microbiological analysis (n = 9), the discs were placed in 12-well plates containing E. faecalis culture and incubated at 37 °C for 7 days. The results show that for the intergroup analysis, considering the "electrolyte" factor, there was a difference between the groups. There was greater biofilm formation for the D.A.Zir group, with greater electrochemical exchange for Biofilm, and the presence of biofilm favored greater electrochemical exchange with the medium.}, } @article {pmid37444240, year = {2023}, author = {Goto, I and Saga, S and Ichitani, M and Kimijima, M and Narisawa, N}, title = {Investigation of Components in Roasted Green Tea That Inhibit Streptococcus mutans Biofilm Formation.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {13}, pages = {}, doi = {10.3390/foods12132502}, pmid = {37444240}, issn = {2304-8158}, abstract = {Streptococcus mutans form oral biofilms (BFs) and cause dental caries. Roasted green tea (RGT) is prepared by roasting the tea plant, and RGT-specific polyphenols are produced during the roasting process. Catechins, polyphenols in green tea, have BF inhibitory activity against S. mutans; therefore, RGT-specific polyphenols are also expected to have this activity. However, there are few reports on the structural and functional properties of RGT. This study aimed to investigate the inhibitory activity of RGT against S. mutans BF formation and to investigate the active compounds. RGT extract fractionation and BF inhibitory assay were performed. Strong activity was confirmed in the RGT fractions that had medium-high hydrophobicity, were rich in phenolic hydroxyl groups, and lacked catechins. A peak comprising compounds with molecular weights of 918 (mw918) and 1050 (mw1050) was purified from the fraction. Since BF inhibitory activity was confirmed for this peak, these compounds were considered to be part of the active ingredients. The mw918 polyphenol was detected only in RGT and it was thought to be produced during the roasting process. The results of this research will serve as a basis for the future application of RGT as a safe and effective anti-caries agent.}, } @article {pmid37442853, year = {2023}, author = {Silva, ML and Carneiro, MN and Cavalcante, RMB and Guerrero, JAP and Fontenelle, ROS and Lorenzón, EN and Cilli, EM and Carneiro, VA}, title = {K-aurein: A notable aurein 1.2-derived peptide that modulates Candida albicans filamentation and reduces biofilm biomass.}, journal = {Amino acids}, volume = {}, number = {}, pages = {}, pmid = {37442853}, issn = {1438-2199}, support = {#2013/07600-3//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {Candida albicans is considered one of the most important opportunistic fungi due to the large arsenal of virulence factors that help throughout the progress of the infection. In this sense, antimicrobial peptides (AMPs) appear as an alternative, with great antifungal action. Among these, aurein 1.2 has been widely explored, becoming the basis for the discovery of new AMPs, such as K-aurein (K-au). Thus, this study evaluated the anti-C. albicans potential of K-au against virulence factors, planktonic growth, and biofilm formation of clinical isolates. Firstly, K-au antifungal activity was determined by the microdilution method and time-kill curve. The inhibition of hydrolytic enzyme secretion (proteinase, phospholipase, and hemolysin) and germ tube formation was tested. Then, the antibiofilm potential of K-au was verified through biomass quantification and scanning electron microscopy (SEM). All tests were compared with the classical antifungal drug, amphotericin B (AmB). The outcomes showed fungicidal action of K-au at 62.50 µg mL[-1] for all isolates, with a time of action around 150-180 min, determined by the time-kill curve. K-au-treated cells decreased by around 40% of the germinative tube compared to the control. Additionally, K-au inhibited the biofilm formation by more than 90% compared to AmB and the control group. SEM images show apparent cellular disaggregation without the formation of filamentous structures. Therefore, the findings suggest a promising anti-C. albicans effect of K-au due to its fungicidal activity against planktonic cells, or its ability to inhibit important virulence factors like germ tube and biofilm formation. Thus, this peptide could be explored as a useful compound against C. albicans-related infection.}, } @article {pmid37441870, year = {2023}, author = {Wu, J and Liu, C and Wang, R and Yan, S and Chen, B and Zhu, X}, title = {Enhanced bacterial adhesion force by rifampicin resistance promotes microbial colonization on PE plastic compared to non-resistant biofilm formation.}, journal = {Water research}, volume = {242}, number = {}, pages = {120319}, doi = {10.1016/j.watres.2023.120319}, pmid = {37441870}, issn = {1879-2448}, abstract = {The microbial biofilm formed on plastics, is ubiquitous in the environment. However, the effects of antibiotic resistance on the development of the biofilm on plastics, especially with regard to initial cell attachment, remain unclear. In this study, we investigated the initial bacterial adhesion and subsequent biofilm growth of a rifampin (Rif) resistant E. coli (RRE) and a normal gram-positive B. subtilis on a typical plastic (polyethylene, PE). The experiments were conducted in different antibiotic solutions, including Rif, sulfamethoxazole (SMX), and kanamycin (KM), with concentrations ranging from 1 to 1000 μg/L to simulate different aquatic environments. The AFM-based single-cell adhesion force determination revealed that Rif resistance strengthened the adhesion force of RRE to PE in the environment rich in Rif rather than SMX and KM. The enhanced adhesion force may be due to the higher secretion of extracellular polymeric substances (EPS), particularly proteins, by RRE in the presence of Rif compared to the other two antibiotics. In addition, the higher ATP level of RRE would facilitate the initial adhesion and subsequent biofilm growth. Transcriptome analysis of RRE separately cultured in Rif and SMX environments demonstrated a clear correlation between the expression of Rif resistance and the augmented bacterial adhesion and cellular activity. Biofilm biomass analysis confirmed the promotion effect of Rif resistance on biofilm growth when compared to non-resistant biofilms, establishing a novel association with the augmentation of microbial adhesion force. Our study highlights concerns related to the dissemination of antibiotic resistance during microbial colonization on plastic that may arise from antibiotic resistance.}, } @article {pmid37441869, year = {2023}, author = {Wang, C and Nakakoji, S and Ng, TCA and Zhu, P and Tsukada, R and Tatara, M and Ng, HY}, title = {Acclimatizing waste activated sludge in a thermophilic anaerobic fixed-bed biofilm reactor to maximize biogas production for food waste treatment at high organic loading rates.}, journal = {Water research}, volume = {242}, number = {}, pages = {120299}, doi = {10.1016/j.watres.2023.120299}, pmid = {37441869}, issn = {1879-2448}, abstract = {Thermophilic anaerobic digestion (TAD) provides a promising solution for sustainable high-strength waste treatment due to its enhanced methane-rich biogas recovery. However, high organic loading rates (OLR) exceeding 3.0 kgCOD/m[3]/day and short hydraulic retention times (HRT) below 10 days pose challenges in waste-to-energy conversion during TAD, stemming from volatile fatty acids (VFAs) accumulation and methanogenesis failure. In this study, we implemented a stepwise strategy for acclimatizing waste activated sludge (WAS) in a thermophilic anaerobic fixed-bed biofilm reactor (TA-FBBR) to optimize methanogen populations, thereby enhancing waste-to-energy efficiencies under elevated OLRs in food waste treatment. Results showed that following stepwise acclimatization, the TA-FBBR achieved stable methane production of approximately 5.8 L/L-reactor/day at an ultrahigh OLR of ∼20 kgCOD/m[3]/day and ∼15 kgVS/m[3]/day at 6-day HRT in food waste treatment. The average methane yield reached 0.45 m[3]/kgCODremoval, attaining the theoretical production in TAD. Moreover, VFA concentrations were stabilized below 1000 mg/L at the ultrahigh OLR under 6-day HRT, while maintaining an acetate/propionate ratio of > 1.8 and a VFA/TAK ratio of < 0.3 serving as effective indicators of system stability and methane yield potential. The microbial community analysis revealed that the WAS acclimatization strategy fostered the microbial diversity and abundance of Methanothermobacter and Methanosarcina. Methanosarcina in the biofilm were observed to be twice as abundant as Methanothermobacter, indicating a potential preference for biofilm existence among methanogens. The findings demonstrated an effective strategy, specifically the stepwise acclimatization of WAS in a thermophilic fixed-bed biofilm reactor, to enhance the food waste treatment performance at high OLRs, contributing valuable mechanistic and technical insights for future sustainable high-strength waste management.}, } @article {pmid37440498, year = {2023}, author = {Schena, NC and Baker, KM and Stark, AA and Thomas, DP and Cleary, IA}, title = {Constitutive ALS3 expression in Candida albicans enhances adhesion and biofilm formation of efg1, but not cph1 mutant strains.}, journal = {PloS one}, volume = {18}, number = {7}, pages = {e0286547}, doi = {10.1371/journal.pone.0286547}, pmid = {37440498}, issn = {1932-6203}, abstract = {Adhesion to living and non-living surfaces is an important virulence trait of the fungal pathogen Candida albicans. Biofilm formation in this organism depends on the expression of a number of cell surface proteins including the hypha-specific protein Als3p. Loss of ALS3 impairs biofilm formation and decreases cell-cell adhesion. We wanted to test whether constitutively expressing ALS3 could compensate for defects in adhesion and biofilm formation observed in mutant strains that lack key transcriptional regulators of biofilm formation Efg1p and Cph1p. We found that ALS3 improved adhesion and biofilm formation in the efg1Δ and efg1Δ cph1Δ mutant strains, but had less effect on the cph1Δ strain.}, } @article {pmid37439829, year = {2023}, author = {Zhao, D and Wang, J and Wang, H and Zhu, X and Han, C and Liu, A}, title = {The Transcription Regulator GntR/HutC Regulates Biofilm Formation, Motility and Stress Tolerance in Lysobacter capsici X2-3.}, journal = {Current microbiology}, volume = {80}, number = {9}, pages = {281}, pmid = {37439829}, issn = {1432-0991}, support = {ZR2021YQ20//National Outstanding Youth Science Fund Project of National Natural Science Foundation of China/ ; SDAIT-04-08//Shandong Modern Agricultural Industry Technology System/ ; 2019JZZY020608//Key Research and Development Program of Shandong Province/ ; 2022-36//Weifang Tobacco Company Science and Technology Project/ ; }, abstract = {Lysobacter capsici X2-3, a plant growth-promoting rhizobacteria (PGPR), was isolated from wheat rhizosphere and has inhibitory effects against a wide range of pathogens. One important characteristic of L. capsici is its ability to produce diverse antibiotics and lytic enzymes. The GntR family of transcription factors is a common transcription factor superfamily in bacteria that has fundamental roles in bacterial metabolism regulation. However, the GntR family transcription factor in Lysobacter has not been identified. In this study, to obtain an understanding of the GntR/HutC gene function in L. capsici X2-3, a random Tn5-insertion mutant library of X2-3 was constructed to select genes showing pleiotropic effects on phenotype. We identified a Tn5 mutant with an insertion in LC4356 that showed reduced biofilm levels, and sequence analysis indicated that the inserted gene encodes a GntR/HutC family transcription regulator. Furthermore, the LC4356 mutant showed reduced extracellular polysaccharide (EPS) production, diminished twitching motility and decreased survival under UV radiation and high-temperature. The RT‒qPCR results indicated that the pentose phosphate pathway-related genes G6PDH, 6PGL and PGDH were upregulated in the LC4356 mutant. Thus, since L. capsici is an efficient biocontrol agent for crop protection, our findings provide fundamental insights into GntR/HutC and will be worthwhile to improve PGPR biocontrol efficacy.}, } @article {pmid37439683, year = {2023}, author = {Biswas, B and Rana, A and Gupta, N and Gupta, I and Puria, R and Thakur, A}, title = {A Novel Robust Method Mimicking Human Substratum To Dissect the Heterogeneity of Candida auris Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0089223}, doi = {10.1128/spectrum.00892-23}, pmid = {37439683}, issn = {2165-0497}, abstract = {Candida auris is a pathogen of urgent threat level as marked by the CDC. The formation of biofilms is an essential property of this fungus to establish infection and escape drug treatment. However, our understanding of pathogenesis through biofilm is hampered by heterogeneity in C. auris biofilms observed in different studies. It is imperative to replicate in vivo conditions for studying C. auris biofilm formation in vitro. Different methods are standardized, but the surface used to form biofilms lacks consistency as well as the architecture of a typical biofilm. Here, we report an in vitro technique to grow C. auris biofilms on gelatin-coated coverslips. Interestingly, C. auris cells grown on gelatin-coated coverslips either on modified synthetic sweat media or RPMI 1640 resulted in similar multilayer biofilm formation with extracellular polymeric substances (EPS). This method is also consistent with the biofilm formation of other Candida species, such as Candida glabrata and Candida albicans. Biofilms of C. glabrata developed through this method show pseudohyphae and EPS. This method can be used to understand the molecular basis of biofilm formation, associated pathogenesis, and drug tolerance. The technique is cost-effective and would thus serve in rightful screening and repurposing drug libraries for designing new therapeutics against the less-studied high-alarm pathogen C. auris. IMPORTANCE Heterogeneity is seen when multidrug-resistant C. auris biofilm is cultured using different reported methods. Biofilm formed on the gelatin surface mimics the condition of a host environment that has multilayers and EPS. This method has feasibility for drug screening and analyzing biofilms through three-dimensional (3D) reconstruction. This in vitro biofilm formation technique is also exploited to study the formation of biofilm of other Candida species. The biofilms of C. glabrata and C. albicans can also be correctly mimicked using gelatin in the biofilm-forming environment. Thus, the novel in vitro method for biofilm formation reported here can be widely used to understand the mechanism of biofilm formation, related virulence properties, and drug tolerance of C. auris and other Candida species. This simple and low-cost technique is highly suitable for screening novel inhibitors and repurposed libraries and to design new therapeutics against Candida species.}, } @article {pmid37437916, year = {2023}, author = {Ferreira, GRS and da Silva, PM and Lopes, W and Feitosa, APS and Coelho, LCBB and Brayner, FA and Alves, LC and Paiva, PMG and de Moura, MC and Vainstein, MH and Napoleão, TH}, title = {Pomegranate sarcotesta lectin (PgTeL) inhibits planktonic growth and disrupts biofilm formed by Cryptococcus neoformans.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad150}, pmid = {37437916}, issn = {1365-2672}, abstract = {AIMS: We investigated the putative fungistatic and fungicidal activities of pomegranate sarcotesta lectin (PgTeL) against Cryptococcus neoformans B3501 (serotype D), specifically the ability of PgTeL to inhibit yeast capsule and biofilm formation in this strain.

METHODS AND RESULTS: PgTeL showed a minimum inhibitory concentration of 172.0 μg ml-1, at which it did not exhibit a fungicidal effect. PgTeL concentrations of 4.0-256.0 μg ml-1 reduced biofilm biomass by 31.0-64.0%. Furthermore, 32.0-256.0 μg/mL PgTeL decreased the metabolic activity of the biofilm by 32.0-93.0%. Scanning electron microscopy images clearly revealed disruption of the biofilm matrix. Moreover, PgTeL disrupted preformed biofilms. At concentrations of 8.0-256.0 μg ml-1, PgTeL reduced metabolic activity in C. neoformans by 36.0-92.0%. However, PgTeL did not inhibit the ability of B3501 cells to form capsules under stress conditions.

CONCLUSIONS: PgTeL inhibited biofilm formation and disrupted preformed biofilms, demonstrating its potential for use as an anticryptococcal agent.}, } @article {pmid37437632, year = {2023}, author = {Mkpuma, VO and Moheimani, NR and Ennaceri, H}, title = {Commercial paper as a promising carrier for biofilm cultivation of Chlorella sp. for the treatment of anaerobic digestate food effluent (ADFE): Effect on the photosynthetic efficiency.}, journal = {The Science of the total environment}, volume = {}, number = {}, pages = {165439}, doi = {10.1016/j.scitotenv.2023.165439}, pmid = {37437632}, issn = {1879-1026}, abstract = {Microalgal technology is still economically unattractive due to the high cost associated with microalgal cultivation and biomass recovery from conventional suspension cultures. Biofilm-based cultivation is a promising alternative for higher biomass yield and cheap/easy biomass harvesting opportunities. Additionally, using anaerobic digestate food effluent (ADFE) as a nutrient source reduces the cultivation cost and achieves ADFE treatment as an added value. However, the search for locally available, inexpensive, and efficient support materials is still open to research. This study evaluates the potential of commercially available, low-cost papers as support material for biofilm cultivation of Chlorella sp. and treatment of ADFE. Among the four papers screened for microalgal attachment, quill board paper performed better in higher biomass yield and stability throughout the study period. The attached growth study was done in a modular food container vessel, using anaerobic digestate food effluent (ADFE) as a nutrient source and a basal medium as a control. The microalgae grew well on the support material with higher biomass yield and productivity of 108.64 g(DW) m[-2] and 9.96 g (DW) m[-2] d[-1], respectively, in the ADFE medium compared with 85.87 g (DW) m[-2] and 4.99 g (DW) m[-2] d[-1], respectively in the basal medium. Chlorophyll, a fluorescence (ChlF) probe, showed that cell density in the biofilm significantly changes the photosynthetic apparatus of the algae, with evidence of stress observed as the culture progressed. Also, efficient nutrient removal from the ADFE medium was achieved in the 100 %, 85 %, and 40.2 % ratios for ammoniacal nitrogen, phosphate, and chemical oxygen demand (COD). Therefore, using quill board paper as carrier material for microalgal cultivation offers promising advantages, including high biomass production, easy biomass harvesting (by scrapping or rolling the biomass with the paper), and efficient effluent treatment.}, } @article {pmid37437616, year = {2023}, author = {Li, H and Wang, K and Xu, J and Wu, H and Ma, Y and Zou, R and Song, HL}, title = {Enhanced removal of antibiotic and antibiotic resistance genes by coupling biofilm electrode reactor and manganese ore substrate up-flow microbial fuel cell constructed wetland system.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139461}, doi = {10.1016/j.chemosphere.2023.139461}, pmid = {37437616}, issn = {1879-1298}, abstract = {Manganese ore substrate up-flow microbial fuel cell constructed wetland (UCW-MFC(Mn)) as an innovative wastewater treatment technology for purifying antibiotics and electricity generation with few antibiotic resistance genes (ARGs) generation has attracted attention. However, antibiotic purifying effects should be further enhanced. In this study, a biofilm electrode reactor (BER) that needs direct current driving was powered by a Mn ore anode (UCW-MFC(Mn)) to form a coupled system without requiring direct-current source. Removal efficiencies of sulfadiazine (SDZ), ciprofloxacin (CIP) and the corresponding ARGs in the coupled system were compared with composite (BER was powered by direct-current source) and anaerobic systems (both of BER and UCW-MFC were in open circuit mode). The result showed that higher antibiotic removal efficiency (94% for SDZ and 99.1% for CIP) in the coupled system was achieved than the anaerobic system (88.5% for SDZ and 98.2% for CIP). Moreover, electrical stimulation reduced antibiotic selective pressure and horizontal gene transfer potential in BER, and UCW-MFC further reduced ARG abundances by strengthening the electro-adsorption of ARG hosts determined by Network analysis. Bacterial community diversity continuously decreased in BER while it increased in UCW-MFC, indicating that BER mitigated the toxicity of antibiotic. Degree of modularity, some functional bacteria (antibiotic degrading bacteria, fermentative bacteria and EAB), and P450 enzyme related to antibiotic and xenobiotics biodegradation genes were enriched in electric field existing UCW-MFC, accounting for the higher degradation efficiency. In conclusion, this study provided an effective strategy for removing antibiotics and ARGs in wastewater by operating a BER-UCW-MFC coupled system.}, } @article {pmid37438162, year = {2023}, author = {Lin, F and Yuan, S and Ji, P and Xu, W}, title = {Regulation of Bacterial Biofilm Formation by Ultrasound: Role of Autoinducer-2 and Finite-Element Analysis of Acoustic Streaming.}, journal = {Ultrasound in medicine & biology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ultrasmedbio.2023.06.016}, pmid = {37438162}, issn = {1879-291X}, abstract = {OBJECTIVE: The formation of bacterial biofilm regulated by quorum sensing (QS) is a critical factor that contributes to infections of indwelling medical devices. Autoinducer-2 (AI-2), as a signal molecule in QS, plays a crucial role in mediating bacterial signaling and regulating their biological behavior. This study investigated the impact of ultrasonic vibration at varying frequencies on biofilm formation in a mixture of Staphylococcus aureus and Escherichia coli.

METHODS: By exciting ultrasound at different frequencies (20, 100 and 200 kHz), a vibration with an amplitude of 100 nm was generated on the material surface located at the bottom of the petri dish containing mixed bacteria. We measured the content of AI-2 and bacteria in the mixed bacterial solution and bioburden on material surfaces at different time points during culture. In addition, the relationships among AI-2 content, bacterial concentration and distribution were assessed through finite-element analysis of acoustic streaming under ultrasonic vibration.

RESULTS: The AI-2 gradient is influenced by the diversity of acoustic streaming patterns on the material surface and in the mixed bacterial solution caused by ultrasonic vibration at different frequencies, thereby regulating biofilm formation. The experimental results showed that the optimal inhibition effect on AI-2 and minimal bacterial adhesion degree was achieved when applying an ultrasonic frequency of 100 kHz with a power intensity of 46.1 mW/cm[2] under an amplitude of 100 nm.

CONCLUSION: Ultrasound can affect the QS system of bacteria, leading to alterations in their biological behavior. Different species of bacteria exhibit varying degrees of chemotaxis toward different frequencies.}, } @article {pmid37436548, year = {2023}, author = {Liu, B and Li, Z and Guo, Q and Guo, X and Liu, R and Liu, X}, title = {Integration of Lysin into Chitosan Nanoparticles for Improving Bacterial Biofilm Inhibition.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37436548}, issn = {1559-0291}, support = {E1E40506//Fundamental Research Funds for the Central Universities/ ; GYY-DTFZ-2022-008//National Key Laboratory of Science, Technology on Advanced Composites in Special Environments, HIT/ ; }, abstract = {Bacterial biofilms (BBFs) exhibit high drug resistance, antiphagocytosis, and extremely strong adhesion, and therefore can cause various diseases. They are also one of the important causes of bacterial infections. Thus, the effective removal of BBFs has attracted considerable research interest. Endolysins, which are efficient antibacterial bioactive macromolecules, have recently been receiving increasing attention. In this study, we overcame the deficiencies of endolysins via immobilization on chitosan nanoparticles (CS-NPs) by preparing LysST-3-CS-NPs using the ionic cross-linking reaction between CS-NPs and LysST-3, an endolysin purified using phage ST-3 expression. The obtained LysST-3-CS-NPs were verified and thoroughly characterized, their antimicrobial activity was investigated using microscopy, and their antibacterial efficacy on polystyrene surfaces was studied. The results obtained suggested that LysST-3-CS-NPs exhibit enhanced bactericidal properties and increased stability and can serve as reliable biocontrol agents for the prevention and treatment of Salmonella biofilm infections.}, } @article {pmid37434702, year = {2023}, author = {Patel, H and Rawat, S}, title = {A genetic regulatory see-saw of biofilm and virulence in MRSA pathogenesis.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1204428}, pmid = {37434702}, issn = {1664-302X}, abstract = {Staphylococcus aureus is one of the most common opportunistic human pathogens causing several infectious diseases. Ever since the emergence of the first methicillin-resistant Staphylococcus aureus (MRSA) strain decades back, the organism has been a major cause of hospital-acquired infections (HA-MRSA). The spread of this pathogen across the community led to the emergence of a more virulent subtype of the strain, i.e., Community acquired Methicillin resistant Staphylococcus aureus (CA-MRSA). Hence, WHO has declared Staphylococcus aureus as a high-priority pathogen. MRSA pathogenesis is remarkable because of the ability of this "superbug" to form robust biofilm both in vivo and in vitro by the formation of polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA), wall teichoic acids (WTAs), and capsule (CP), which are major components that impart stability to a biofilm. On the other hand, secretion of a diverse array of virulence factors such as hemolysins, leukotoxins, enterotoxins, and Protein A regulated by agr and sae two-component systems (TCS) aids in combating host immune response. The up- and downregulation of adhesion genes involved in biofilm formation and genes responsible for synthesizing virulence factors during different stages of infection act as a genetic regulatory see-saw in the pathogenesis of MRSA. This review provides insight into the evolution and pathogenesis of MRSA infections with a focus on genetic regulation of biofilm formation and virulence factors secretion.}, } @article {pmid37433138, year = {2023}, author = {Kong, B and Jin, L and Zhao, Y and Huang, H and Wang, Y and Ren, H}, title = {Adaptive Evolution Laws of Biofilm under Emerging Pollutant-Induced Stress: Community Assembly-Driven Structure Response.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c01899}, pmid = {37433138}, issn = {1520-5851}, abstract = {The widely used biofilm process in advanced wastewater treatment is currently challenged by numerous exotic emerging pollutants (EPs), and the underlying principle of the challenge is the adaptive evolution laws of biofilm under EP stress. However, there is still a knowledge gap in exploration of the biofilm adaptive evolution theory. Herein, we comprehensively analyzed the morphological variation, community succession, and assembly mechanism of biofilms to report the mechanism underlying their adaptive evolution under sulfamethoxazole and carbamazepine stress for the first time. The ecological role of the dominant species was driven as a pioneer and assembly hub by EP stress, and the deterministic processes indicated the functional basis of the transformation. In addition, the characteristic responses of dispersal limitation and homogenizing dispersal adequately revealed the assembly pathways in adaptive evolution and the resulting structural variation. Therefore, the "interfacial exposure-structural variation-mass transfer feedback" mechanism was inferred to underly the adaptive evolution process of biofilms. Overall, this study highlighted the internal drivers of the adaptive evolution of the biofilm at the phylogenetic level and deepened our understanding of the mechanism of biofilm development under EP stress in advanced wastewater purification.}, } @article {pmid37432640, year = {2023}, author = {Maurya, S and Gaur, M and Yadav, AB}, title = {Staphylococcus aureus Biofilm Destabilization by Tween-80 and Lung Surfactants to Overcome Biofilm-Imposed Drug Resistance.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37432640}, issn = {1559-0291}, abstract = {This study is aimed to evaluating the potential of tween-80 and artificial lung surfactant (ALS) to destabilize S. aureus biofilm. The biofilm destabilization was studied by crystal violet staining, bright field microscopy, and scanning electron microscopy (SEM). During the study, S. aureus biofilm was exposed with tween-80 along various concentrations (1%, 0.1%, and 0.05%) or LS (lung surfactant) at (2.5%, 5%, and 15%) for 2 hrs. It was observed that 0.1% of tween-80 destabilized 63.83 ± 4.35% and 15% ALS 77 ± 1.7% biofilm in comparison to without treatment. The combination of tween-80 and ALS was used and showed a synergistic effect to destabilize 83.4 ± 1.46% biofilm. These results showed the potential of tween-80 and ALS as biofilm disruptors, which further needs to explore in an in-vivo animal model to access the actual potential of biofilm disruption in natural conditions. This study could play a pivotal role to overcome the problem of antibiotic resistance imposed due to biofilm formation to combat antibiotic resistance imposed by bacteria.}, } @article {pmid37430988, year = {2022}, author = {Heng, Y and Wang, M and Jiang, H and Gao, S and Zhang, J and Wan, J and Song, T and Ren, Z and Zhu, Y}, title = {Plasma-Activated Acidic Electrolyzed Water: A New Food Disinfectant for Bacterial Suspension and Biofilm.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {20}, pages = {}, doi = {10.3390/foods11203241}, pmid = {37430988}, issn = {2304-8158}, support = {2020CFB777//Natural Science Foundation of Hubei Province/ ; }, abstract = {Food-borne diseases are widespread all over the world, and food safety has attracted much attention. This study is the first to use plasma to activate acidic electrolyzed water (AEW) to obtain a new disinfectant for food processing. The germicidal efficacy of plasma-activated acidic electrolyzed water (PA-AEW) on B. subtilis suspension and biofilm was investigated. Furthermore, the synergistic effect of different bactericidal factors was inferred by investigating the physicochemical parameters of PA-AEW and the influencing factors of bactericidal effect. The results demonstrate that PA-AEW is a highly effective and rapid disinfectant. The killing logarithm (KL) value of PA-AEW on B. subtilis suspension could reach 2.33 log10CFU/mL with a sterilization time of 10 s, which is significantly higher than that of AEW (KL = 0.58 log10CFU/mL) and plasma-activated water (PAW) (KL = 0.98 log10CFU/mL) (significant difference, p < 0.01). Moreover, the KL value of the B. subtilis biofilm of PA-AEW was 2.41 log10CFU/mL, better than that of PAW and AEW (significant difference, p < 0.01), indicating that PA-AEW has important application prospects in food processing. The synergistic effect should come from the interaction between reactive chlorine species (RCS) and reactive oxygen and nitrogen species (RONS) in PA-AEW.}, } @article {pmid37429611, year = {2023}, author = {Hajigholamreza, H and Sharifzadeh, A and Hassan, J and Shokri, H and Akbaripazouki, A and Pakbin, B and Tamai, IA}, title = {Influence of menthol on biofilm formation, ergosterol content, and cell surface hydrophobicity of Candida glabrata.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnad065}, pmid = {37429611}, issn = {1574-6968}, abstract = {Resistance to synthetic antifungals has become one of the leading public health challenges around the world. Accordingly, novel antifungal products like naturally occurring molecules can be one of the potential ways to reach efficient curative approaches to control candidiasis. This work evaluated the effect of menthol on cell surface hydrophobicity (CSH), biofilm formation, growth and ergosterol content of Candida glabrata (C. glabrata), a yeast with a high resistance against antifungal agents. Disc diffusion method (susceptibility to synthetic antifungals), broth micro-dilution method (Susceptibility to menthol), MTT reduction assay (biofilm formation), HPLC technique (ergosterol content) and adherence to n-hexadecane (CSH) were employed to determine the influence of menthol against C. glabrata isolates. The MIC range of menthol versus C. glabrata was 1250-5000 µg/mL (mean ± SD: 3375 ± 1375 µg/mL). The mean rate of C. glabrata biofilm formation was decreased up to 97.67, 81.15, 71.21, 63.72, 47.53, 26.31 and 0.051% at 625, 1250, 2500, 5000, 10 000, 20 000 and 40 000 µg/mL concentrations, respectively. The percentages of CSH were significantly in groups treated with MIC/2 (17.51 ± 5.52%) and MIC/4 (26 ± 5.87%) concentrations of menthol. Also, the percentage changes in membrane ergosterol were 15.97, 45.34 and 73.40% at 0.125, 0.25 and 0.5 mg/mL concentrations of menthol, respectively, in comparison with untreated control. The results showed the menthol impact versus sessile and planktonic C. glabrata cells, and the interference with ergosterol content, CSH, and biofilm formation, which made it a potent natural antifungal.}, } @article {pmid37429429, year = {2023}, author = {E, R and Vishwakarma, A and Balakrishnan, A and Mohandass, R}, title = {Assessment of the growth inhibition and anti-biofilm activity of aptamer (PmA2G02) against Proteus mirabilis 1429T.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104105}, doi = {10.1016/j.resmic.2023.104105}, pmid = {37429429}, issn = {1769-7123}, abstract = {Proteus mirabilis is known to cause Catheter-associated urinary tract infections (CAUTIs), which exhibit virulence factors linked to forming biofilms. Aptamers have recently been explored as potential anti-biofilm agents. This study demonstrates the anti-biofilm activity of aptamer (PmA2G02) targeting Proteus mirabilis 1429[T], a pathogenic bacteria known to cause Catheter-associated urinary tract infections (CAUTIs). The studied aptamer inhibited biofilm formation, swarming motility, and cell viability at a concentration of 3 μM. The study also showed that the PmA2G02 had a binding affinity towards fimbrial outer membrane usher protein (PMI1466), flagellin protein (PMI1619), and regulator of swarming behavior (rsbA), which are responsible for adhesion, motility, and quorum sensing, respectively. Crystal violet assay, SEM, and confocal imaging confirmed the effectiveness of the PmA2G02 as an anti-biofilm agent. Moreover, as verified by qPCR, the expression levels of fimD, fliC2, and rsbA were significantly reduced compared to the untreated group. This study suggests that aptamer may be a potential alternative to traditional antibiotics for the treatment of CAUTIs caused by P. mirabilis. These findings shed light on the mechanisms by which the aptamer inhibits biofilm formation.}, } @article {pmid37429971, year = {2023}, author = {Heo, S and Oh, SE and Lee, G and Lee, J and Ha, NC and Jeon, CO and Jeong, K and Lee, JH and Jeong, DW}, title = {Staphylococcus equorum plasmid pKS1030-3 encodes auxiliary biofilm formation and trans-acting gene mobilization systems.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {11108}, pmid = {37429971}, issn = {2045-2322}, support = {NRF-2019R1A2C1003639//National Research Foundation of Korea/ ; }, abstract = {The foodborne bacterium Staphylococcus equorum strain KS1030 harbours plasmid pSELNU1, which encodes a lincomycin resistance gene. pSELNU1 undergoes horizontal transfer between bacterial strains, thus spreading antibiotic resistance. However, the genes required for horizontal plasmid transfer are not encoded in pSELNU1. Interestingly, a relaxase gene, a type of gene related to horizontal plasmid transfer, is encoded in another plasmid of S. equorum KS1030, pKS1030-3. The complete genome of pKS1030-3 is 13,583 bp long and encodes genes for plasmid replication, biofilm formation (the ica operon), and horizontal gene transfer. The replication system of pKS1030-3 possesses the replication protein-encoding gene repB, a double-stranded origin of replication, and two single-stranded origins of replication. The ica operon, relaxase gene, and a mobilization protein-encoding gene were detected in pKS1030-3 strain-specifically. When expressed in S. aureus RN4220, the ica operon and relaxase operon of pKS1030-3 conferred biofilm formation ability and horizontal gene transfer ability, respectively. The results of our analyses show that the horizontal transfer of pSELNU1 of S. equorum strain KS1030 depends on the relaxase encoded by pKS1030-3, which is therefore trans-acting. Genes encoded in pKS1030-3 contribute to important strain-specific properties of S. equorum KS1030. These results could contribute to preventing the horizontal transfer of antibiotic resistance genes in food.}, } @article {pmid37428599, year = {2023}, author = {Kumar, D and Kumar, A}, title = {Cellular Attributes of Candida albicans Biofilm-Associated in Resistance Against Multidrug and Host Immune System.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {}, number = {}, pages = {}, doi = {10.1089/mdr.2022.0347}, pmid = {37428599}, issn = {1931-8448}, abstract = {One of the ubiquitous hospital-acquired infections is associated with Candida albicans fungus. Usually, this commensal fungus causes no harm to its human host, as it lives mutually with mucosal/epithelial tissue surface cells. Nevertheless, due to the activity of various immune weakening factors, this commensal starts reinforcing its virulence attributes with filamentation/hyphal growth and building an absolute microcolony composed of yeast, hyphal, and pseudohyphal cells, which is suspended in an extracellular gel-like polymeric substance (EPS) called biofilms. This polymeric substance is the mixture of the secreted compounds from C. albicans as well as several host cell proteins. Indeed, the presence of these host factors makes their identification and differentiation process difficult by host immune components. The gel-like texture of the EPS makes it sticky, which adsorbs most of the extracolonial compounds traversing through it that aid in penetration hindrance. All these factors further contribute to the multidrug resistance phenotype of C. albicans biofilm that is spotlighted in this article. The mechanisms it employs to escape the host immune system are also addressed effectively. The article focuses on cellular and molecular determinants involved in the resistance of C. albicans biofilm against multidrug and the host immune system.}, } @article {pmid37428387, year = {2023}, author = {Ray, RR}, title = {Role of Virus on Oral Biofilm: Inducer or Eradicator?.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37428387}, issn = {1559-0291}, abstract = {Sessile forms of bacteria remain as an aggregation on biotic and abiotic surfaces, known as biofilm, that protects them from various environmental stress, like antibiotic and host immune response. The oral cavity is enriched with microbial biofilm, formed on dental surface, gingival plaques, and associated tissue. Several pathogenic viruses enter the oral cavity and form biofilms either on pre-existing biofilms or on cell surfaces. They achieved persistence and the ability to prompt dissemination in the biofilm. Dental biofilms of COVID-19 patients are found to harbor SARS-CoV-2 RNA and may act as a budding reservoir, which also promotes COVID-19 transmission. On the other hand, most of the prokaryotic viruses or bacteriophages essentially kill the host bacteria and thereby destroy the biofilm. Bacteria try to evade from phage attack by concealing in biofilm, whereas the eukaryotic virus often utilize bacterial biofilm to escape host's immune response and to achieve an easy way of dissemination. The opposite action of viruses as an inducer and eradicator of biofilm has made the oral biofilm a unique ecosystem.}, } @article {pmid37428036, year = {2023}, author = {Lopez, AE and Grigoryeva, LS and Barajas, A and Cianciotto, NP}, title = {Legionella pneumophila Rhizoferrin Promotes Bacterial Biofilm Formation and Growth within Amoebae and Macrophages.}, journal = {Infection and immunity}, volume = {}, number = {}, pages = {e0007223}, doi = {10.1128/iai.00072-23}, pmid = {37428036}, issn = {1098-5522}, abstract = {Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene (lbtA) in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both lbtA and feoB. This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The lbtA feoB mutant, but not its lbtA-containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the lbtA feoB mutant, but not its complement containing lbtA, proved to be greatly impaired for growth in Acanthamoeba castellanii, Vermamoeba vermiformis, and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of Legionella. Outside of Legionella, the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.}, } @article {pmid37424779, year = {2023}, author = {Aguilera-Correa, JJ and Nohynek, L and Alakomi, HL and Esteban, J and Oksman-Caldentey, KM and Puupponen-Pimiä, R and Kinnari, TJ and Perez-Tanoira, R}, title = {Reduction of methicillin-resistant Staphylococcus aureus biofilm growth and development using arctic berry extracts.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1176755}, pmid = {37424779}, issn = {2235-2988}, abstract = {INTRODUCTION: Surgical site infection remains a devastating and feared complication of surgery caused mainly by Staphylococcus aureus (S. aureus). More specifically, methicillin-resistant S. aureus (MRSA) infection poses a serious threat to global health. Therefore, developing new antibacterial agents to address drug resistance are urgently needed. Compounds derived from natural berries have shown a strong antimicrobial potential.

METHODS: This study aimed to evaluate the effect of various extracts from two arctic berries, cloudberry (Rubus chamaemorus) and raspberry (Rubus idaeus), on the development of an MRSA biofilm and as treatment on a mature MRSA biofilm. Furthermore, we evaluated the ability of two cloudberry seed-coat fractions, hydrothermal extract and ethanol extract, and the wet-milled hydrothermal extract of a raspberry press cake to inhibit and treat biofilm development in a wound-like medium. To do so, we used a model strain and two clinical strains isolated from infected patients.

RESULTS: All berry extracts prevented biofilm development of the three MRSA strains, except the raspberry press cake hydrothermal extract, which produced a diminished anti-staphylococcal effect.

DISCUSSION: The studied arctic berry extracts can be used as a treatment for a mature MRSA biofilm, however some limitations in their use exist.}, } @article {pmid37424668, year = {2023}, author = {Aldarhami, A and Bazaid, AS and Qanash, H and Ahmad, I and Alshammari, FH and Alshammari, AM and Alshammari, AH and Aljanfawe, FM and Aldamiri, B and Aldawood, E and Alghamdi, MA and Binsaleh, NK and Saeedi, NH and Snoussi, M}, title = {Effects of Repeated in-vitro Exposure to Saudi Honey on Bacterial Resistance to Antibiotics and Biofilm Formation.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {4273-4283}, pmid = {37424668}, issn = {1178-6973}, abstract = {INTRODUCTION: Although Sumra and Sidr Saudi honey is widely used in traditional medicine due to its potent activity, it is unknown whether its prolonged usage has impact upon bacterial virulence or leading to reduced antibiotic sensitivity. Thus, the study aims to investigate the effect of prolonged (repeated) in-vitro exposure to Saudi honey on the antibiotic susceptibility profiles and biofilm formation of pathogenic bacteria.

METHODS: Several bacteria, including Staphylococcus aureus, Escherichia coli, and Acinetobacter baumannii, were in-vitro exposed ten times [passaged (P10)]to Sumra and Sider honey individually to introduce adapted bacteria (P10). Antibiotic susceptibility profiles of untreated (P0) and adapted (P10) bacteria were assessed using disc diffusion and microdilution assays. The tendency regarding biofilm formation following in-vitro exposure to honey (P10) was assessed using the Crystal violet staining method.

RESULTS: Adapted (P10) bacteria to both Sumra and Sidr honey showed an increased sensitivity to gentamicin, ceftazidime, ampicillin, amoxycillin/clavulanic acid, and ceftriaxone, when compared with the parent strains (P0). In addition, A. baumannii (P10) that was adapted to Sidr honey displayed a 4-fold increase in the minimal inhibitory concentration of the same honey following in-vitro exposure. 3-fold reduction in the tendency toward biofilm formation was observed for the Sumra-adapted (P10) methicillin resistant S. aureus strain, although there was a lower rate of reduction (1.5-fold) in biofilm formation by both the Sumra- and Sidr-adapted A. baumannii (P10) strains.

CONCLUSION: The data highlight the positive impact of prolonged in-vitro exposure to Saudi honey (Sumra and Sider) for wound-associated bacteria since they displayed a significant increase in their sensitivity profiles to the tested antibiotic and a reduction in their ability to form biofilm. The increased bacterial sensitivity to antibiotics and a limited tendency toward biofilm formation would suggest the great potential therapeutic use of this Saudi honey (Sumra and Sidr) to treat wound infections.}, } @article {pmid37423498, year = {2023}, author = {Gervasoni, LF and Peixoto, IC and Imperador, AC and De Oliveira, LB and Correia, LF and de Oliveira Vieira, KC and Saeki, EK and da Silva Lima, PE and Mareco, EA and Pereira, VC and Winkelströter Eller, LK}, title = {"Relationship between antibiotic resistance, biofilm formation, virulence factors and source of origin of Pseudomonas aeruginosa environmental isolates with regard to the presence of metallo-β-lactamase-encoding genes".}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106223}, doi = {10.1016/j.micpath.2023.106223}, pmid = {37423498}, issn = {1096-1208}, abstract = {A total of 557 water samples were evaluated and of these, 23 were positive for the presence of Pseudomonas aeruginosa. Approximately 91.7% of them were weak biofilm formers. Only 4 isolates showed antimicrobial resistance. All isolates presented Twitching motility, a positive result for the production of pyocyanin, alkaline protease, and hemolysins. The genotypic tests showed: lasA, (95.6%) lasB (95.6%), exoS (95.6%), exoT (91.3%), toxA (91.3%), akgO (91.3%), plcN (91.3%) aprA (86.9%), phzM (78.3%), and pvdA (60.9%). For genes encoding metallo-beta-lactamase, it was found: blaVIM (56.6%), blaSPM (4.3%), and blaSIM (47.8%). A strong association was found between the metallo-beta-lactamase producing genes, nine genes of virulence factors and the motility (r = 0.6231). The very close clonal profile suggests a probable similarity between the isolates from different cities. Thus, P. aeruginosa can be present in water supplies with variable virulence capacities and can generate a huge concern for human, animal, and environmental health.}, } @article {pmid37423195, year = {2023}, author = {Benahmed, A and Seghir, A and Boucherit-Otmani, Z and Tani, ZZBA and Aissaoui, M and Kendil, W and Merabet, DH and Lakhal, H and Boucherit, K}, title = {In vitro evaluation of biofilm formation by Candida parapsilosis and Enterobacter cloacae. Scanning electron microscopy and efficacy of antimicrobial combinations study.}, journal = {Diagnostic microbiology and infectious disease}, volume = {107}, number = {1}, pages = {116003}, doi = {10.1016/j.diagmicrobio.2023.116003}, pmid = {37423195}, issn = {1879-0070}, abstract = {Fungal-bacterial infections are being increasingly recognized in clinical settings, and the interaction between these species in polymicrobial biofilms often lead to infections that are highly resistant to treatment. In this in vitro study, we analyzed the formation of mixed biofilms using clinically isolated Candida parapsilosis and Enterobacter cloacae. Additionally, we assessed the potential of conventional antimicrobials, both alone and in combination, for treating polymicrobial biofilms built by these human pathogens. Our results demonstrate that C. parapsilosis and E. cloacae are capable of forming mixed biofilms, as confirmed by scanning electron microscopy. Interestingly, we found that colistin alone or in combination with antifungal drugs was highly effective reducing up to 80% of the total biomass of polymicrobial biofilms.}, } @article {pmid37422719, year = {2023}, author = {Alawadi, A and AbdulAzees, PA and Lin, CY and Haney, SJ and Hanlon, JP and Angelara, K and Taft, RM and Amaechi, BT}, title = {Application of Organoselenium in inhibiting Candida albicans biofilm adhesion on 3D printed denture base material.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {}, number = {}, pages = {}, doi = {10.1111/jopr.13733}, pmid = {37422719}, issn = {1532-849X}, abstract = {PURPOSE: Denture Stomatitis, a chronic mucosal inflammation associated with Candida albicans, is common among denture wearers. Several health conditions have been linked to chronic Candida infections. The complex, multifactorial nature of denture stomatitis requires the continuous pursuit of effective long-term solutions. The present in vitro study investigated the effect of incorporating organoselenium into 3D-printed denture base resin on Candida albicans adhesion and biofilm formation.

MATERIALS AND METHODS: Thirty disks were fabricated using 3D-printed denture base resin and assigned to 3 experimental groups (10/group): disks without organoselenium (control), disks with 0.5% organoselenium (0.5%SE), and disks with 1% organoselenium (1%SE). Each disk was incubated with approximately 1 × 10[6] cells/mL of Candida albicans for 48 hours. Microbial viability (CFU/mL) was quantified by the spread plate method, while Confocal laser scanning microscopy and scanning electron microscope were performed for quantifying the biofilm thickness and examining biofilm morphology, respectively. Data were analyzed using One-way ANOVA with Tukey's multiple comparisons test.

RESULTS: CFU/mL was significantly (P<0.05) higher in Control when compared with 0.5%SE and 1%SE, but no significant difference between 0.5%SE and 1%SE. A similar trend was observed with biofilm thickness except that there was no significant difference between the Control and 0.5%SE. There was C. albicans biofilm adhesion on the Control disks, with yeast cells and hyphae formation, whereas on 0.5%SE and 1%SE, there was inhibition of yeast cells transition to hyphae formation.

CONCLUSIONS: Incorporation of organoselenium into 3D-printed denture base resin was effective in reducing Candida albicans biofilm formation and growth on denture base material. This article is protected by copyright. All rights reserved.}, } @article {pmid37418244, year = {2023}, author = {Hamza, M and Sivaraman, GK and Mothadaka, MP}, title = {Multidrug-resistant phenotypes among biofilm-producing staphylococcal isolates from farm-raised fishes: A molecular scrutiny.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad136}, pmid = {37418244}, issn = {1365-2672}, abstract = {AIMS: To describe the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from farm-raised fishes.

METHODS AND RESULTS: Fish samples (n=180) collected from aquaculture farms in three major districts of Kerala, yielded 45 methicillin-resistant staphylococci (MRS) (25%) isolates. All of the isolates were resistant to tested beta-lactams and 19 (42.22%) were resistant to flouroquinolones. According to the resistance profile of each isolate, 33 of 45 (73.33%) are identified as multidrug-resistant (MDR) isolates with an average multiple antibiotic resistance (MAR) index of 0.41±0.09. Notably, virulence determinants such as classical enterotoxin (sea & seb), and SE-like toxin (seg & sei) genes co-existed with Antimicrobial Resistance Genes (ARGs) in isolates studied. Regardless of the isolates being strong biofilm producers, only 23 (51.1%) harbored icaA and icaD genes. The heterogeneity of MRSA (n=17) clones were evident as the species belonged to three major spa types (t345, t2526, t1309) and sequence types (STs) viz., ST772, ST88, ST672.

CONCLUSION: The current study on molecular characterization of the MRS isolates sheds light on the preventive measures that need to be implemented to limit the spread of AMR pathogens in aquaculture.}, } @article {pmid37417809, year = {2023}, author = {He, J and Cui, S and Hou, Y and Liu, S and Zhang, Z and Zhao, M and He, L and Wang, R and Liu, S}, title = {Bifunctional defect mediated direct Z-scheme g-C3N4-x/Bi2O3-y heterostructures with enhanced piezo-photocatalytic properties for efficient tooth whitening and biofilm eradication.}, journal = {Journal of materials chemistry. B}, volume = {}, number = {}, pages = {}, doi = {10.1039/d3tb01044a}, pmid = {37417809}, issn = {2050-7518}, abstract = {Biofilm-associated dental diseases and tooth discoloration have recently become the major barriers to achieve healthy teeth. However, there are few effective strategies to address these issues. Herein, the piezo-photocatalytic process is first proposed to be applied for biofilm eradication and tooth whitening with well-designed direct Z scheme g-C3N4-x/Bi2O3-y heterostructures. DFT calculation and XPS results verify the formation of direct Z scheme g-C3N4/Bi2O3 heterostructures theoretically and experimentally. Using the direct Z scheme g-C3N4-x/Bi2O3-y heterostructure, excellent piezo-photocatalytic effects for tooth whitening and biofilm removal are achieved. For piezo-photocatalytic degradation of the typical food colorant of indigo carmine the degradation rate constant is about quadruple that of piezocatalytic and 2.6 times of photocatalytic treatment. Tooth whitening experiments indicate that g-C3N4-x/Bi2O3-y could whiten the stained teeth through the synergistic piezo-photocatalysis. In addition, excellent antibacterial performances can be obtained on the g-C3N4-x/Bi2O3-y heterostructure through piezo-photocatalytic treatment. Not only the planktonic S. mutans but also those bacteria embedded in biofilms can be effectively killed. The analyses of the piezo-photocatalytic mechanism indicates that the enhanced piezo-photocatalytic performance of the g-C3N4-x/Bi2O3-y heterostructure could be attributed to the much higher separation efficiency of photoexcited charge carriers, increased production amounts of ROS and superior adsorption ability for bacteria than those with bare semiconductors of g-C3N4-x and Bi2O3-y and those treated only with ultrasonic vibration or irradiation. Biosafety results show that the g-C3N4-x/Bi2O3-y heterostructure is biologically safe and piezo-photocatalytic treatment has no harm the tooth structure, demonstrating the great potential of piezo-photocatalytic effect based new tooth whitening and antibacterial technology in future dental care fields.}, } @article {pmid37417759, year = {2023}, author = {Element, SJ and Moran, RA and Beattie, E and Hall, RJ and van Schaik, W and Buckner, MMC}, title = {Growth in a biofilm promotes conjugation of a bla NDM-1-bearing plasmid between Klebsiella pneumoniae strains.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0017023}, doi = {10.1128/msphere.00170-23}, pmid = {37417759}, issn = {2379-5042}, abstract = {Antimicrobial resistance (AMR) is a growing problem, especially in Gram-negative Enterobacteriaceae such as Klebsiella pneumoniae. Horizontal transfer of conjugative plasmids contributes to AMR gene dissemination. Bacteria such as K. pneumoniae commonly exist in biofilms, yet most studies focus on planktonic cultures. Here we studied the transfer of a multi-drug resistance plasmid in planktonic and biofilm populations of K. pneumoniae. We determined plasmid transfer from a clinical isolate, CPE16, which carried four plasmids, including the 119-kbp blaNDM-1-bearing F-type plasmid pCPE16_3, in planktonic and biofilm conditions. We found that transfer frequency of pCPE16_3 in a biofilm was orders-of-magnitude higher than between planktonic cells. In 5/7 sequenced transconjugants (TCs) multiple plasmids had transferred. Plasmid acquisition had no detectable growth impact on TCs. Gene expression of the recipient and a transconjugant was investigated by RNA-sequencing in three lifestyles: planktonic exponential growth, planktonic stationary phase, and biofilm. We found that lifestyle had a substantial impact on chromosomal gene expression, and plasmid carriage affected chromosomal gene expression most in stationary planktonic and biofilm lifestyles. Furthermore, expression of plasmid genes was lifestyle-dependent, with distinct signatures across the three conditions. Our study shows that growth in biofilm greatly increased the risk of conjugative transfer of a carbapenem resistance plasmid in K. pneumoniae without fitness costs and minimal transcriptional rearrangements, thus highlighting the importance of biofilms in the spread of AMR in this opportunistic pathogen. IMPORTANCE Carbapenem-resistant K. pneumoniae is particularly problematic in hospital settings. Carbapenem resistance genes can transfer between bacteria via plasmid conjugation. Alongside drug resistance, K. pneumoniae can form biofilms on hospital surfaces, at infection sites and on implanted devices. Biofilms are naturally protected and can be inherently more tolerant to antimicrobials than their free-floating counterparts. There have been indications that plasmid transfer may be more likely in biofilm populations, thus creating a conjugation "hotspot". However, there is no clear consensus on the effect of the biofilm lifestyle on plasmid transfer. Therefore, we aimed to explore the transfer of a plasmid in planktonic and biofilm conditions, and the impact of plasmid acquisition on a new bacterial host. Our data show transfer of a resistance plasmid is increased in a biofilm, which may be a significant contributing factor to the rapid dissemination of resistance plasmids in K. pneumoniae.}, } @article {pmid37416858, year = {2023}, author = {Rudin, L and Bornstein, MM and Shyp, V}, title = {Inhibition of biofilm formation and virulence factors of cariogenic oral pathogen Streptococcus mutans by natural flavonoid phloretin.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2230711}, pmid = {37416858}, issn = {2000-2297}, abstract = {OBJECTIVES: To evaluate the effect and mechanism of action of the flavonoid phloretin on the growth and sucrose-dependent biofilm formation of Streptococcus mutans.

METHODS: Minimum inhibitory concentration, viability, and biofilm susceptibility assays were conducted to assess antimicrobial and antibiofilm effect of phloretin. Biofilm composition and structure were analysed with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Water-soluble (WSG) and water-insoluble glucan (WIG) were determined using anthrone method. Lactic acid measurements and acid tolerance assay were performed to assess acidogenicity and aciduricity. Reverse transcription quantitative PCR (RT-qPCR) was used to measure the expression of virulence genes essential for surface attachment, biofilm formation, and quorum sensing.

RESULTS: Phloretin inhibited S. mutans growth and viability in a dose-dependent manner. Furthermore, it reduced gtfB and gtfC gene expression, correlating with the reduction of extracellular polysaccharides (EPS)/bacteria and WIG/WSG ratio. Inhibition of comED and luxS gene expression, involved in stress tolerance, was associated with compromised acidogenicity and aciduricity of S. mutans.

CONCLUSIONS: Phloretin exhibits antibacterial properties against S. mutans, modulates acid production and tolerance, and reduces biofilm formation.

CLINICAL SIGNIFICANCE: Phloretin is a promising natural compound with pronounced inhibitory effect on key virulence factors of the cariogenic pathogen, S. mutans.}, } @article {pmid37414100, year = {2023}, author = {Zdarta, A and Kaczorek, E}, title = {Nanomechanical changes in probiotic bacteria under antibiotics exposure: Implications on Lactobacillus biofilm formation.}, journal = {Biochimica et biophysica acta. Molecular cell research}, volume = {}, number = {}, pages = {119533}, doi = {10.1016/j.bbamcr.2023.119533}, pmid = {37414100}, issn = {1879-2596}, abstract = {Recognition of the microbial cell's surface constituents' biophysical properties is an important research topic, allowing a better understanding of the cell's behaviour under different conditions. Atomic force microscopy (AFM) was employed in this study to analyse the basis of the nanomechanical changes in probiotic bacteria under nitrofurantoin, furazolidone, and nitrofurazone exposure. Recorded significant changes in the two Lactobacillus strains cells morphology, topography, and adhesion parameters resulted in the increase of the cells' longitude (up to 2.58 μm), profile height (by around 0.50 μm), and decrease in the adhesion force (up to 13.58 nN). Young's modulus and adhesion energy decreased within 96 h, however with no negative effect on the cells' morphology or loss of structural integrity. Observed modifications present the mode of action of the 5-nitrofuran derivative antibiotics on probiotic biofilm formation and suggest activation of the multilevel adaptation mechanisms to counteract unfavorable environments. A visual change in bacterial morphology such as an increased surface-to-volume ratio might be a link between molecular-level events and outcomes in individual cells and biofilms. This paper for the first time shows, that these antibiotics affect the properties of non-target microorganisms as lactobacilli, and might impair biofilm formation. However, the degree of such transformations depends on the delivered active substance.}, } @article {pmid37413798, year = {2023}, author = {Wu, T and Zhong, L and Ding, J and Pang, JW and Sun, HJ and Ding, MQ and Ren, NQ and Yang, SS}, title = {Microplastics perturb nitrogen removal, microbial community and metabolism mechanism in biofilm system.}, journal = {Journal of hazardous materials}, volume = {458}, number = {}, pages = {131971}, doi = {10.1016/j.jhazmat.2023.131971}, pmid = {37413798}, issn = {1873-3336}, abstract = {Microplastics (MPs) are a significant component of global pollution and cause widespread concern, particularly in wastewater treatment plants. While understanding the impact of MPs on nutrient removal and potential metabolism in biofilm systems is limited. This work investigated the impact of polystyrene (PS) and polyethylene terephthalate (PET) on the performance of biofilm systems. The results revealed that at concentrations of 100 and 1000 μg/L, both PS and PET had almost no effect on the removal of ammonia nitrogen, phosphorus, and chemical oxygen demand, but reduced the removal of total nitrogen by 7.40-16.6%. PS and PET caused cell and membrane damage, as evidenced by increases in reactive oxygen species and lactate dehydrogenase to 136-355% and 144-207% of the control group. Besides, metagenomic analysis demonstrated both PS and PET changed the microbial structure and caused functional differences. Some important genes in nitrite oxidation (e.g. nxrA), denitrification (e.g. narB, nirABD, norB, and nosZ), and electron production process (e.g. mqo, sdh, and mdh) were restrained, meanwhile, species contribution to nitrogen-conversion genes was altered, therefore disturbing nitrogen-conversion metabolism. This work contributes to evaluating the potential risks of biofilm systems exposed to PS and PET, maintaining high nitrogen removal and system stability.}, } @article {pmid37410609, year = {2023}, author = {Tornero-Gutiérrez, F and Ortiz-Ramírez, JA and López-Romero, E and Cuéllar-Cruz, M}, title = {Materials used to prevent adhesion, growth and biofilm formation of Candida species.}, journal = {Medical mycology}, volume = {}, number = {}, pages = {}, doi = {10.1093/mmy/myad065}, pmid = {37410609}, issn = {1460-2709}, abstract = {The species of the Candida genus are opportunistic pathogenic fungi found in humans and are responsible for approximately 80% of worldwide fungal infections. Aimed to diminish and preventing Candida adhesion to cells or implanted devices in the human host, a large diversity of materials has been developed and functionalized that have attracted much interest. Furthermore, these materials have been focused almost exclusively on Candida albicans, followed by Candida glabrata, Candida parapsilosis, and Candida tropicalis. Although an important diversity of materials have been synthesized to prevent adherence and formation of biofilms by Candida species, it is however important to evaluate the capacity of each material in terms of its property to diminish the adherence of Candida. These materials are discussed in this review.}, } @article {pmid37410300, year = {2023}, author = {Tan, X and Hu, M and Cheng, X and Xiao, J and Zhou, J and Zhu, G}, title = {Effects of elevated levels of intracellular nitric oxide on Pseudomonas aeruginosa biofilm in chronic skin wound and slow-killing infection models.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37410300}, issn = {1618-1905}, support = {32200152//National Natural Science Foundation of China/ ; 32000091//National Natural Science Foundation of China/ ; 2108085QC92//Natural Science Foundation of Anhui Province/ ; 202003a06020009//Major Science and Technology Projects in Anhui Province/ ; 2022AH010012//Outstanding Innovative Research Team for Molecular Enzymology and Detection in Anhui Provincial Universities/ ; }, abstract = {Nitric oxide (NO), produced through the denitrification pathway, regulates biofilm dynamics through the quorum sensing system in Pseudomonas aeruginosa. NO stimulates P. aeruginosa biofilm dispersal by enhancing phosphodiesterase activity to decrease cyclic di-GMP levels. In a chronic skin wound model containing a mature biofilm, the gene expression of nirS, encoding nitrite reductase to produce NO, was low, leading to reduced intracellular NO levels. Although low-dose NO induces biofilm dispersion, it is unknown whether it influences the formation of P. aeruginosa biofilms in chronic skin wounds. In this study, a P. aeruginosa PAO1 strain with overexpressed nirS was established to investigate NO effects on P. aeruginosa biofilm formation in an ex vivo chronic skin wound model and unravel the underlying molecular mechanisms. Elevated intracellular NO levels altered the biofilm structure in the wound model by inhibiting the expression of quorum sensing-related genes, which was different from an in vitro model. In Caenorhabditis elegans as a slow-killing infection model, elevated intracellular NO levels increased worms' lifespan by 18%. Worms that fed on the nirS-overexpressed PAO1 strain for 4 h had complete tissue, whereas worms that fed on empty plasmid-containing PAO1 had biofilms on their body, causing severe damage to the head and tail. Thus, elevated intracellular NO levels can inhibit P. aeruginosa biofilm growth in chronic skin wounds and reduce pathogenicity to the host. Targeting NO is a potential approach to control biofilm growth in chronic skin wounds wherein P. aeruginosa biofilms are a persistent problem.}, } @article {pmid37410258, year = {2023}, author = {Kumar, D and Kumar, A}, title = {Molecular Determinants Involved in Candida albicans Biofilm Formation and Regulation.}, journal = {Molecular biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37410258}, issn = {1559-0305}, abstract = {Candida albicans is known for its pathogenicity, although it lives within the human body as a commensal member. The commensal nature of C. albicans is well controlled and regulated by the host's immune system as they live in the harmonized microenvironment. However, the development of certain unusual microhabitat conditions (change in pH, co-inhabiting microorganisms' population ratio, debilitated host-immune system) pokes this commensal fungus to transform into a pathogen in such a way that it starts to propagate very rapidly and tries to breach the epithelial barrier to enter the host's systemic circulations. In addition, Candida is infamous as a major nosocomial (hospital-acquired infection) agent because it enters the human body through venous catheters or medical prostheses. The hysterical mode of C. albicans growth builds its microcolony or biofilm, which is pathogenic for the host. Biofilms propose additional resistance mechanisms from host immunity or extracellular chemicals to aid their survival. Differential gene expressions and regulations within the biofilms cause altered morphology and metabolism. The genes associated with adhesiveness, hyphal/pseudo-hyphal growth, persister cell transformation, and biofilm formation by C. albicans are controlled by myriads of cell-signaling regulators. These genes' transcription is controlled by different molecular determinants like transcription factors and regulators. Therefore, this review has focused discussion on host-immune-sensing molecular determinants of Candida during biofilm formation, regulatory descriptors (secondary messengers, regulatory RNAs, transcription factors) of Candida involved in biofilm formation that could enable small-molecule drug discovery against these molecular determinants, and lead to disrupt the well-structured Candida biofilms effectively.}, } @article {pmid37408920, year = {2023}, author = {Canham, R and Rourke, J and Ydenberg, RC}, title = {The exploitation of biofilm by migrant western sandpipers (Calidrismauri).}, journal = {Heliyon}, volume = {9}, number = {6}, pages = {e17268}, pmid = {37408920}, issn = {2405-8440}, abstract = {Assessing the quality of migratory shorebird stopover sites requires good measures of food availability. We developed simple methods to measure biofilm grazing by migrant western sandpipers (Calidris mauri), a species for which biofilm is an important dietary component. We used a field-portable chlorofluorometer to measure the density of chlorophyll-a (Chl-a) in surficial biofilms on Roberts Bank, a large intertidal mudflat in British Columbia, Canada, during northward migration. Chl-a density begins at a low level during each diurnal emersion period, and increases steadily during emersion at 4.1 mg m[-2] h[-1] for a total of ∼24.6 mg m[-2] over a typical 6 h emersion period and ∼41 mg m[-2] over a 10 h emersion period. Western sandpipers grazed at 1.35-1.45 mg Chl-a m[-2] min[-1], thus biofilm production supports 17.6 min m[-2] of grazing time during a 6 h low tide period and 29.3 min m[-2] during a 10 h period. During peak northward migration, the average grazing intensity of western sandpipers over an intertidal emersion period was 3.3-6.4 min m[-2], suggesting that biofilm accumulation was 2.7-8.8 fold greater than the amount consumed. We found Chl-a density was highest (∼65 mg per m[2]) within 40 m of the shoreline. Grazing intensity was lowest close to shore, where predation risk from falcon attacks is highest. Grazing intensity peaked at 240 m and then declined, lowering Chl-a density at greater distances to a uniform level of ∼54 mg m[-2]. These results indicate that interactions between biofilm production and sandpiper grazing underlie spatio-temporal patterns in biofilm abundance on Roberts Bank.}, } @article {pmid37408643, year = {2023}, author = {Su, BA and Chen, CC and Chen, HJ and Lai, HY and Tsai, CH and Lai, CC and Tang, HJ and Chao, CM}, title = {In vitro activities of antimicrobial combinations against planktonic and biofilm forms of Stenotrophomonas maltophilia.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1186669}, pmid = {37408643}, issn = {1664-302X}, abstract = {OBJECTIVES: To investigate the in vitro activity of antibiotic combinations against Stenotrophomonas maltophilia isolates and their associated biofilms.

METHODS: Thirty-two S. maltophilia clinical isolates with at least twenty-five different pulsotypes were tested. The antibacterial activity of various antibiotic combinations against seven randomly selected planktonic and biofilm-embedded S. maltophilia strains with strong biofilm formation was assessed using broth methods. Extraction of bacterial genomic DNA and PCR detection of antibiotic resistance and biofilm-related genes were also performed.

RESULTS: The susceptibility rates of levofloxacin (LVX), fosfomycin (FOS), tigecycline (TGC) and sulfamethoxazole-trimethoprim (SXT) against 32 S. maltophilia isolates were 56.3, 71.9, 71.9 and 90.6%, respectively. Twenty-eight isolates were detected with strong biofilm formation. Antibiotic combinations, including aztreonam-clavulanic (ATM-CLA) with LVX, ceftazidime-avibactam (CZA) with LVX and SXT with TGC, exhibited potent inhibitory activity against these isolates with strong biofilm formation. The antibiotic resistance phenotype might not be fully caused by the common antibiotic-resistance or biofilm-formation gene.

CONCLUSION: S. maltophilia remained resistant to most antibiotics, including LVX and β-lactam/β-lactamases; however, TGC, FOS and SXT still exhibited potent activity. Although all tested S. maltophilia isolates exhibited moderate-to-strong biofilm formation, combination therapies, especially ATM-CLA with LVX, CZA with LVX and SXT with TGC, exhibited a higher inhibitory activity for these isolates.}, } @article {pmid37407919, year = {2023}, author = {Verma, S and Kumari, M and Pathak, A and Yadav, V and Johri, AK and Yadav, P}, title = {Antibiotic resistance, biofilm formation, and virulence genes of Streptococcus agalactiae serotypes of Indian origin.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {176}, pmid = {37407919}, issn = {1471-2180}, support = {ECR/2015/000431)//SERB Deprtment of science and technology Govt of India/ ; ECR/2015/000431)//SERB Deprtment of science and technology Govt of India/ ; ECR/2015/000431)//SERB Deprtment of science and technology Govt of India/ ; }, abstract = {BACKGROUND: Group B Streptococcus (GBS) is a causative agent of various infections in newborns, immunocompromised (especially diabetic) non-pregnant adults, and pregnant women. Antibiotic resistance profiling can provide insights into the use of antibiotic prophylaxis against potential GBS infections. Virulence factors are responsible for host-bacteria interactions, pathogenesis, and biofilm development strategies. The aim of this study was to determine the biofilm formation capacity, presence of virulence genes, and antibiotic susceptibility patterns of clinical GBS isolates.

RESULTS: The resistance rate was highest for penicillin (27%; n = 8 strains) among all the tested antibiotics, which indicates the emergence of penicillin resistance among GBS strains. The susceptibility rate was highest for ofloxacin (93%; n = 28), followed by azithromycin (90%; n = 27). Most GBS strains (70%; n = 21) were strong biofilm producers and the rest (30%; n = 9) were moderate biofilm producers. The most common virulence genes were cylE (97%), pavA (97%), cfb (93%), and lmb (90%). There was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility, according to Spearman's rank correlation analysis.

CONCLUSION: About a third of GBS strains exhibited penicillin resistance and there was a negative association between having a strong biofilm formation phenotype and penicillin susceptibility. Further, both the strong and moderate biofilm producers carried most of the virulence genes tested for, and the strong biofilm formation phenotype was not associated with the presence of any virulence genes.}, } @article {pmid37407800, year = {2023}, author = {Meneses, L and Brandão, AC and Coenye, T and Braga, AC and Pires, DP and Azeredo, J}, title = {A systematic review of the use of bacteriophages for in vitro biofilm control.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37407800}, issn = {1435-4373}, support = {UIDB/04469/2020//Fundação para a Ciência e a Tecnologia/ ; SFRH/BD/07494/2020//Fundação para a Ciência e a Tecnologia/ ; No reference//European Society of Clinical Microbiology and Infectious Diseases/ ; }, abstract = {Bacteriophages (phages) are very promising biological agents for the prevention and control of bacterial biofilms. However, little is known about the parameters that can influence the efficacy of phages on biofilms. This systematic review provides a summary and analysis of the published data about the use of phages to control pre-formed biofilms in vitro, suggesting recommendations for future experiments in this area. A total of 68 articles, containing data on 605 experiments addressing the efficacy of phages to control biofilms in vitro were included, after a search conducted in Web of Science, Embase, and Medline (PubMed). The data collected from each experiment included information about biofilm growth conditions, phage characteristics, treatment conditions and biofilm reduction. In most cases, biofilms were formed in the surface of microtiter plates (82.5%); the median time for biofilm formation was 24 h, as is the median treatment duration. Quantification of biofilm biomass (52.6%), viable cells (25.5%) and metabolic activity (17.9%) were the most common biofilm assessment methods. Correlation analysis revealed that some phage parameters can influence the treatment outcome: higher phage concentrations were strongly associated with improved biofilm control, leading to higher levels of biofilm reduction, and phages with higher burst sizes and shorter latent periods seem to be the best candidates to control biofilms in vitro. However, the great variability of the methodologies used prompts the need for the development of standardized in vitro methodologies to characterize phage/biofilm interactions and to assess the efficacy of phages to control biofilms.}, } @article {pmid37405980, year = {2023}, author = {Song, Y and Lin, L and Qi, WK and Sasaki, O and Li, YY}, title = {Anammox-Mediated Hydroxyapatite Granules: Physicochemical Properties, 3D Hierarchy, and Biofilm Thickness.}, journal = {Environmental science & technology}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.est.3c00596}, pmid = {37405980}, issn = {1520-5851}, abstract = {Biomineralization inspired the development of simultaneous biological transformations and chemical precipitation for simultaneous nitrogen removal and phosphorus recovery from wastewater, which could compensate for the incapacity of phosphorus management in the new biological route of anaerobic ammonium oxidation (anammox). In this study, we strengthened anammox-mediated biomineralization by long-term feeding of concentrated N, P, and Ca substrates, and a self-assembled matrix of anammox bacteria and hydroxyapatite (HAP) was fabricated in a granular shape, defined as HAP-anammox granules. HAP was identified as the dominant mineral using elemental analysis, X-ray diffraction, and Raman spectroscopy. The intensive precipitation of HAP resulted in a higher inorganic fraction and substantially improved settleability of anammox biomass, which facilitated HAP precipitation by acting as nucleation and metabolically elevated pH. By using X-ray microcomputed tomography, we visually represented the hybrid texture of interwoven HAP pellets and biomass, the core-shell layered architecture of different-sized HAP-anammox granules, and their homogeneously regulated thickness of the outer biofilm (from 118 to 635 μm). This unique architecture endows HAP-anammox granules with outstanding settleability, active biofilm, and tightly bonded biofilm with the carrier, which may explain the excellent performance of these HAP-anammox granules under various challenging operational conditions in previous studies.}, } @article {pmid37405939, year = {2023}, author = {Dietrich, M and Besser, M and Debus, ES and Smeets, R and Stuermer, EK}, title = {Human skin biofilm model: translational impact on swabbing and debridement.}, journal = {Journal of wound care}, volume = {32}, number = {7}, pages = {446-455}, doi = {10.12968/jowc.2023.32.7.446}, pmid = {37405939}, issn = {0969-0700}, abstract = {OBJECTIVE: Wound biofilms are one of the greatest challenges in the therapy of hard-to-heal (chronic) wounds, as potent antimicrobial substances fail to eradicate bacteria within short incubation periods. Preclinical investigations using novel model systems that closely mimic the human wound environment and wound biofilm are required to identify new and effective therapeutic options. This study aims to identify bacterial colonisation patterns that are relevant for diagnosis and therapy.

METHOD: In this study, a recently established human plasma biofilm model (hpBIOM) was incorporated into a wound within human dermal resectates after abdominoplasty. The interaction of the biofilm-forming bacteria meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa with the skin cells was investigated. Possible effects on wound healing processes in correlation with the persistence of the biofilm in the wound environment were analysed in patients with leg ulcers of different aetiologies and biofilm burden.

RESULTS: Using haematoxylin and eosin staining, species-dependent infiltration modes of the bacteria into the wound tissue were determined for the pathogens MRSA and Pseudomonas aeruginosa. The spreading behaviour correlated with clinical observations of the spatial distributions of the bacteria. In particular, the clinically prominent Pseudomonas aeruginosa-specific distension of the wound margin was identified as epidermolysis due to persistent infiltration.

CONCLUSION: The hpBIOM applied in this study represents a potential tool for preclinical analyses dealing with approval processes for new antimicrobial applications. In terms of clinical practice, a microbiological swabbing technique including the wound margin should be routinely applied to prevent wound exacerbation.}, } @article {pmid37404726, year = {2023}, author = {Kirienko, NV and Di, YP}, title = {Editorial: Role of microbial biofilm in infections.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1231607}, pmid = {37404726}, issn = {2235-2988}, } @article {pmid37404052, year = {2023}, author = {Sana, A and Qurashi, AW and Moqaddes, S}, title = {Microbial bio-film calcite mediated removal of heavy metals from industrial wastewater of Kasur, Pakistan.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300232}, pmid = {37404052}, issn = {1521-4028}, abstract = {Heavy metals in the industrial wastewater are an area of great concern as act as source of bioaccumulation in edible plants and posing a major health risk to humans like cancers. This study was planned by exploiting the bio-film producing microbes that have the potential to remediate heavy metals by calcite mediated removal from industrial wastewater. Samples (n = 10) from a marble factory wastewater were collected. Samples were serially diluted and were spread on nutrient agar media supplemented with 2% urea and 0.28 g calcium chloride. All the isolates were observed for colony morphology, gram staining, and spore staining, for biochemical profile and for their efficacy in producing calcium carbonate crystals. All isolates showed cell densities at varying metal (chromium) concentrations ranging from 100 to 500 µg/mL. Determination of biofilm formation is performed by recording Optical density (OD = 600 nm). Normalized biofilm (570/600 nm) was formed. Different concentrations of chromium were used to measure their reduction ability and also by using tannery water. In tannery wastewater, significant reduction was recorded (p = 0.05) by AS4 bacterial isolate as compared to rest of the isolates and treatments. It showed remarkable chromium VI reduction ability.}, } @article {pmid37403810, year = {2023}, author = {Haddad, Y and Chan, WC and Ha, WN and Conde, A and Estevez, R and Lopez, AP and Gates, GC and Rossi-Fedele, G}, title = {The effect of a preparation containing glycocholic acid on the biocidal efficacy of sodium hypochlorite in a biofilm laboratory model.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {}, number = {}, pages = {}, doi = {10.1111/aej.12771}, pmid = {37403810}, issn = {1747-4477}, abstract = {This study assessed the antimicrobial effect of sodium hypochlorite (NaOCl) mixtures combined with Keratobacter (KB) using an engineered biofilm root canal model. Clinical and reagent grade NaOCl were mixed with KB (9:1-vol/vol) to assess pH values over 1 min to select the ideal solution with a pH just below the pKa of hypochlorous acid. The samples were randomly divided into five groups: 1% and 4% NaOCl reagents, a mixture of NaOCl:KB using 1% and 4% NaOCl reagents and distilled water. Outcome measures were colony-forming units (CFUs/mL) and positive/negative cultures. No significant differences were observed in the pairwise comparisons between 1%, 4% NaOCl and 4% NaOCl+KB for the outcome CFUs/mL. Only 4% NaOCl presented with negative cultures in all samples, whereas 1% NaOCl and 4% NaOCl+KB had similar results (54% vs. 40%). The addition of KB has a limited effect on the antimicrobial efficacy of 4% NaOCl in this laboratory model.}, } @article {pmid37402603, year = {2023}, author = {Huang, R and Li, Q and Wang, D and Feng, H and Zhang, N and Shao, J and Shen, Q and Xu, Z and Zhang, R}, title = {Novel fatty acids-governed cannibalism in beneficial rhizosphere Bacillus enhances biofilm formation via a two-component system OmpS/R and toxin transporter.}, journal = {Science bulletin}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.scib.2023.06.022}, pmid = {37402603}, issn = {2095-9281}, } @article {pmid37402327, year = {2023}, author = {Shen, B and Yang, L and Xu, H and Zhang, Y and Ming, D and Zhu, L and Wang, Y and Jiang, L}, title = {Detection and treatment of biofilm-induced periodontitis by histidine-doped FeSN nanozyme with ultra-high peroxidase-like activity.}, journal = {Journal of colloid and interface science}, volume = {650}, number = {Pt A}, pages = {211-221}, doi = {10.1016/j.jcis.2023.06.188}, pmid = {37402327}, issn = {1095-7103}, abstract = {Pathogenic biofilm induced oral diseases have posed a significant treat to human health, such as periodontitis resulting from the formation of bacterial biofilm on teeth and gums. The traditional treatment methods such as mechanical debridement and antibiotic therapy encounter the poor therapeutic effect. Recently, numerous nanozymes with excellent antibacterial effect have been widely used in the treatment of oral diseases. In this study, a novel iron-based nanozyme (FeSN) generated by histidine-doped FeS2 with high peroxidase-like (POD-like) activity was designed for the oral biofilm removal and treatment of periodontitis. FeSN exhibited an extremely high POD-like activity, and enzymatic reaction kinetics and theoretical calculations had demonstrated its catalytic efficiency to be approximately 30 times than that of FeS2. The antibacterial experiments showed that FeSN had robust antibacterial activity against Fusobacterium nucleatum in the presence of H2O2, causing a reduction in the levels of glutathione reductase and ATP in bacterial cells, while increasing the level of oxidase coenzyme. The ultrahigh POD-like activity of FeSN allowed for easy detection of pathogenic biofilms and promoted the breakdown of biofilm structure. Furthermore, FeSN demonstrated excellent biocompatibility and low cytotoxicity to human fibroblast cells. In a rat model of periodontitis, FeSN exhibited significant therapeutic effects by reducing the extent of biofilm formation, inflammation, and alveolar bone loss. Taken together, our results suggested that FeSN, generated by self-assembly of two amino acids, represented a promising approach for biofilm removal and periodontitis treatment. This method has the potential to overcome the limitations of current treatments and provide an effective alternative for periodontitis treatment.}, } @article {pmid37401756, year = {2023}, author = {Aleksandrowicz, A and Carolak, E and Dutkiewicz, A and Błachut, A and Waszczuk, W and Grzymajlo, K}, title = {Better together-Salmonella biofilm-associated antibiotic resistance.}, journal = {Gut microbes}, volume = {15}, number = {1}, pages = {2229937}, doi = {10.1080/19490976.2023.2229937}, pmid = {37401756}, issn = {1949-0984}, abstract = {Salmonella poses a serious threat to public health and socioeconomic development worldwide because of its foodborne pathogenicity and antimicrobial resistance. This biofilm-planktonic lifestyle enables Salmonella to interfere with the host and become resistant to drugs, conferring inherent tolerance to antibiotics. The complex biofilm structure makes bacteria tolerant to harsh conditions due to the diversity of physiological, biochemical, environmental, and molecular factors constituting resistance mechanisms. Here, we provide an overview of the mechanisms of Salmonella biofilm formation and antibiotic resistance, with an emphasis on less-studied molecular factors and in-depth analysis of the latest knowledge about upregulated drug-resistance-associated genes in bacterial aggregates. We classified and extensively discussed each group of these genes encoding transporters, outer membrane proteins, enzymes, multiple resistance, metabolism, and stress response-associated proteins. Finally, we highlighted the missing information and studies that need to be undertaken to understand biofilm features and contribute to eliminating antibiotic-resistant and health-threatening biofilms.}, } @article {pmid37400003, year = {2023}, author = {Khataybeh, B and Jaradat, Z and Ababneh, Q}, title = {Anti-bacterial, anti-biofilm and anti-quorum sensing activities of honey: A review.}, journal = {Journal of ethnopharmacology}, volume = {}, number = {}, pages = {116830}, doi = {10.1016/j.jep.2023.116830}, pmid = {37400003}, issn = {1872-7573}, abstract = {Man has used honey to treat diseases since ancient times, perhaps even before the history of medicine itself. Several civilizations have utilized natural honey as a functional and therapeutic food to ward off infections. Recently, researchers worldwide have been focusing on the antibacterial effects of natural honey against antibiotic-resistant bacteria.

AIM OF THE STUDY: This review aims to summarize research on the use of honey properties and constituents with their anti-bacterial, anti-biofilm, and anti-quorum sensing mechanisms of action. Further, honey's bacterial products, including probiotic organisms and antibacterial agents which are produced to curb the growth of other competitor microorganisms is addressed.

MATERIALS AND METHODS: In this review, we have provided a comprehensive overview of the antibacterial, anti-biofilm, and anti-quorum sensing activities of honey and their mechanisms of action. Furthermore, the review addressed the effects of antibacterial agents of honey from bacterial origin. Relevant information on the antibacterial activity of honey was obtained from scientific online databases such as Web of Science, Google Scholar, ScienceDirect, and PubMed.

RESULTS: Honey's antibacterial, anti-biofilm, and anti-quorum sensing activities are mostly attributed to four key components: hydrogen peroxide, methylglyoxal, bee defensin-1, and phenolic compounds. The performance of bacteria can be altered by honey components, which impact their cell cycle and cell morphology. To the best of our knowledge, this is the first review that specifically summarizes every phenolic compound identified in honey along with their potential antibacterial mechanisms of action. Furthermore, certain strains of beneficial lactic acid bacteria such as Bifidobacterium, Fructobacillus, and Lactobacillaceae, as well as Bacillus species can survive and even grow in honey, making it a potential delivery system for these agents.

CONCLUSION: Honey could be regarded as one of the best complementary and alternative medicines. The data presented in this review will enhance our knowledge of some of honey's therapeutic properties as well as its antibacterial activities.}, } @article {pmid37398495, year = {2023}, author = {Glazier, VE and Kramara, J and Ollinger, T and Solis, NV and Zarnowski, R and Wakade, RS and Kim, MJ and Weigel, GJ and Liang, SH and Bennett, RJ and Wellington, M and Andes, DR and Stamnes, MA and Filler, SG and Krysan, DJ}, title = {The Candida albicans reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates biofilm formation and oral commensalism.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, doi = {10.1101/2023.06.17.545405}, pmid = {37398495}, abstract = {UNLABELLED: Candida albicans is a diploid human fungal pathogen that displays significant genomic and phenotypic heterogeneity over a range of virulence traits and in the context of a variety of environmental niches. Here, we show that the effects of Rob1 on biofilm and filamentation virulence traits is dependent on both the specific environmental condition and the clinical strain of C. albicans . The C. albicans reference strain SC5314 is a ROB1 heterozygote with two alleles that differ by a single nucleotide polymorphism at position 946 resulting in a serine or proline containing isoform. An analysis of 224 sequenced C. albicans genomes indicates that SC5314 is the only ROB1 heterozygote documented to date and that the dominant allele contains a proline at position 946. Remarkably, the ROB1 alleles are functionally distinct and the rare ROB1 [946S] allele supports increased filamentation in vitro and increased biofilm formation in vitro and in vivo, suggesting it is a phenotypic gain-of-function allele. SC5314 is amongst the most highly filamentous and invasive strains characterized to date. Introduction of the ROB1 [946S] allele into a poorly filamenting clinical isolate increases filamentation and conversion of an SC5314 laboratory strain to a ROB1 [946S] homozygote increases in vitro filamentation and biofilm formation. In a mouse model of oropharyngeal infection, the predominant ROB1 [946P] allele establishes a commensal state while the ROB1 [946S] phenocopies the parent strain and invades into the mucosae. These observations provide an explanation for the distinct phenotypes of SC5314 and highlight the role of heterozygosity as a driver of C. albicans phenotypic heterogeneity.

IMPORTANCE: Candida albicans is a commensal fungus that colonizes human oral cavity and gastrointestinal tracts but also causes mucosal as well as invasive disease. The expression of virulence traits in C. albicans clinical isolates is heterogenous and the genetic basis of this heterogeneity is of high interest. The C. albicans reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates. Here, we show that SC5314 derivatives are heterozygous for the transcription factor Rob1 and contain an allele with a rare gain-of-function SNP that drives filamentation, biofilm formation, and virulence in a model of oropharyngeal candidiasis. These finding explain, in part, the outlier phenotype of the reference strain and highlight the role of heterozygosity plays in the strain-to-strain variation of diploid fungal pathogens.}, } @article {pmid37397004, year = {2023}, author = {Mao, Y and Wang, Y and Luo, X and Chen, X and Wang, G}, title = {Impact of cell-free supernatant of lactic acid bacteria on Staphylococcus aureus biofilm and its metabolites.}, journal = {Frontiers in veterinary science}, volume = {10}, number = {}, pages = {1184989}, pmid = {37397004}, issn = {2297-1769}, abstract = {INTRODUCTION: A safe bio-preservative agent, lactic acid bacteria (LAB) can inhibit the growth of pathogenic bacteria and spoilage organisms. Its cell-free supernatant (LAB-CFS), which is rich in bioactive compounds, is what makes LAB antibacterial work.

METHODS: This study focused on the changes in biofilm activity and related metabolic pathways of S. aureus treated with lactic acid bacteria planktonic CFS (LAB-pk-CFS) and biofilm state (LAB-bf-CFS).

RESULTS: The findings demonstrated that the LAB-CFS treatment considerably slowed Staphylococcus aureus (S. aureus) growth and prevented it from forming biofilms. Additionally, it inhibits the physiological traits of the S. aureus biofilm, including hydrophobicity, motility, eDNA, and PIA associated to the biofilm. The metabolites of S. aureus biofilm treated with LAB-CFS were greater in the LAB-bf-CFS than they were in the LAB-pk-CFS, according to metabolomics studies. Important metabolic pathways such amino acids and carbohydrates metabolism were among the most noticeably altered metabolic pathways.

DISCUSSION: These findings show that LAB-CFS has a strong potential to combat S. aureus infections.}, } @article {pmid37396463, year = {2023}, author = {Žiemytė, M and Rodríguez-Díaz, JC and Ventero-Martín, MP and Mira, A and Ferrer, MD}, title = {Real-time monitoring of biofilm growth identifies andrographolide as a potent antifungal compound eradicating Candida biofilms.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100134}, pmid = {37396463}, issn = {2590-2075}, abstract = {Candida species cause life-threatening infections with high morbidity and mortality rates and their resistance to conventional therapy is closely linked to biofilm formation. Thus, the development of new approaches to study Candida biofilms and the identification of novel therapeutic strategies could yield improved clinical outcomes. In the current study, we have set up an impedance-based in vitro system to study Candida spp. biofilms in real-time and to evaluate their sensitivity to two conventional antifungal groups used in clinical practice - azoles and echinocandins. Both fluconazole and voriconazole were unable to inhibit biofilm formation in most strains tested, while echinocandins showed biofilm inhibitory capacity at relatively low concentrations (starting from 0.625 mg/L). However, assays performed on 24 h Candida albicans and C. glabrata biofilms revealed that micafungin and caspofungin failed to eradicate mature biofilms at all tested concentrations, evidencing that once formed, Candida spp. biofilms are extremely difficult to eliminate using currently available antifungals. We then evaluated the antifungal and anti-biofilm effect of andrographolide, a natural compound isolated from the plant Andrographis paniculata with known antibiofilm activity on Gram-positive and Gram-negative bacteria. Optical density measures, impedance evaluation, CFU counts, and electron microscopy data showed that andrographolide strongly inhibits planktonic Candida spp. growth and halts Candida spp. biofilm formation in a dose-dependent manner in all tested strains. Moreover, andrographolide was capable of eliminating mature biofilms and viable cell numbers by up to 99.9% in the C. albicans and C. glabrata strains tested, suggesting its potential as a new approach to treat multi-resistant Candida spp. biofilm-related infections.}, } @article {pmid37396462, year = {2023}, author = {Youf, R and Ghanem, R and Nasir, A and Lemercier, G and Montier, T and Le Gall, T}, title = {Impact of mucus and biofilm on antimicrobial photodynamic therapy: Evaluation using Ruthenium(II) complexes.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100113}, pmid = {37396462}, issn = {2590-2075}, abstract = {The biofilm lifestyle of bacterial pathogens is a hallmark of chronic lung infections such as in cystic fibrosis (CF) patients. Bacterial adaptation to the complex conditions in CF-affected lungs and repeated antibiotherapies lead to increasingly tolerant and hard-to-treat biofilms. In the context of growing antimicrobial resistance and restricted therapeutic options, antimicrobial photodynamic therapy (aPDT) shows great promise as an alternative to conventional antimicrobial modalities. Typically, aPDT consists in irradiating a non-toxic photosensitizer (PS) to generate reactive oxygen species (ROS), which kill pathogens in the surrounding environment. In a previous study, we reported that some ruthenium (II) complexes ([Ru(II)]) can mediate potent photodynamic inactivation (PDI) against planktonic cultures of Pseudomonas aeruginosa and Staphylococcus aureus clinical isolates. In the present work, [Ru(II)] were further assayed to evaluate their ability to photo-inactivate such bacteria under more complex experimental conditions better recapitulating the microenvironment in lung infected airways. Bacterial PDI was tentatively correlated with the properties of [Ru(II)] in biofilms, in mucus, and following diffusion across the latter. Altogether, the results obtained demonstrate the negative impacting role of mucus and biofilm components on [Ru(II)]-mediated PDT, following different possible mechanisms of action. Technical limitations were also identified that may be overcome, making this report a pilot for other similar studies. In conclusion, [Ru(II)] may be subjected to specific chemical engineering and/or drug formulation to adapt their properties to the harsh micro-environmental conditions of the infected respiratory tract.}, } @article {pmid37395749, year = {2023}, author = {Li, R and Hou, M and Yu, L and Luo, W and Kong, J and Yu, R and Liu, R and Li, Q and Tan, L and Pan, C and Wang, H}, title = {Anti-biofilm effect of salivary histatin 5 on Porphyromonas gingivalis.}, journal = {Applied microbiology and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37395749}, issn = {1432-0614}, support = {81800974//National Natural Science Foundation of China/ ; 82101027//National Natural Science Foundation of China/ ; 2023-MS-173//Natural Science Foundation of Liaoning Province/ ; }, abstract = {This study aimed to investigate the effects of salivary histatin 5 (Hst5) on Porphyromonas gingivalis (P. gingivalis) biofilms in vitro and in vivo and the possible mechanisms. In in vitro experiments, P. gingivalis biomass was determined by crystal violet staining. Polymerase chain reaction, scanning electron microscopy, and confocal laser scanning microscopy were used to determine the Hst5 concentration. A search for potential targets was performed using transcriptomic and proteomic analyses. In vivo experimental periodontitis was established in rats to evaluate the effects of Hst5 on periodontal tissues. Experimental results showed that 25 µg/mL Hst5 effectively inhibited biofilm formation, and increased concentrations of Hst5 increased the inhibitive effect. Hst5 might bind to the outer membrane protein RagAB. A combination of transcriptomic and proteomic analyses revealed that Hst5 could regulate membrane function and metabolic processes in P. gingivalis, in which RpoD and FeoB proteins were involved. In the rat periodontitis model, alveolar bone resorption and inflammation levels in periodontal tissues were reduced by 100 µg/mL Hst5. This study showed that 25 µg/mL Hst5 inhibited P. gingivalis biofilm formation in vitro by changing membrane function and metabolic process, and RpoD and FeoB proteins might play important roles in this process. Moreover, 100 µg/mL Hst5 inhibited periodontal inflammation and alveolar bone loss in rat periodontitis via its antibacterial and anti-inflammatory effects. KEY POINTS: • Anti-biofilm activity of histatin 5 on Porphyromonas gingivalis was investigated. • Histatin 5 inhibited Porphyromonas gingivalis biofilm formation. • Histatin 5 showed inhibitory effects on the occurrence of rat periodontitis.}, } @article {pmid37395583, year = {2023}, author = {El Masry, M and Bhasme, P and Mathew-Steiner, SS and Smith, J and Smeenge, T and Roy, S and Sen, CK}, title = {Swine Model of Biofilm Infection and Invisible Wounds.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {196}, pages = {}, doi = {10.3791/65301}, pmid = {37395583}, issn = {1940-087X}, abstract = {Biofilm infection is a major contributor to wound chronicity. The establishment of clinically relevant experimental wound biofilm infection requires the involvement of the host immune system. Iterative changes in the host and pathogen during the formation of such clinically relevant biofilm can only occur in vivo. The swine wound model is recognized for its advantages as a powerful pre-clinical model. There are several reported approaches for studying wound biofilms. In vitro and ex vivo systems are deficient in terms of the host immune response. Short-term in vivo studies involve acute responses and, thus, do not allow for biofilm maturation, as is known to occur clinically. The first long-term swine wound biofilm study was reported in 2014. The study recognized that biofilm-infected wounds may close as determined by planimetry, but the skin barrier function of the affected site may fail to be restored. Later, this observation was validated clinically. The concept of functional wound closure was thus born. Wounds closed but deficient in skin barrier function may be viewed as invisible wounds. In this work, we seek to report the methodological details necessary to reproduce the long-term swine model of biofilm-infected severe burn injury, which is clinically relevant and has translational value. This protocol provides detailed guidance on establishing an 8 week wound biofilm infection using P. aeruginosa (PA01). Eight full-thickness burn wounds were created symmetrically on the dorsum of domestic white pigs, which were inoculated with (PA01) at day 3 post-burn; subsequently, noninvasive assessments of the wound healing were conducted at different time points using laser speckle imaging (LSI), high-resolution ultrasound (HUSD), and transepidermal water loss (TEWL). The inoculated burn wounds were covered with a four-layer dressing. Biofilms, as established and confirmed structurally by SEM at day 7 post-inoculation, compromised the functional wound closure. Such an adverse outcome is subject to reversal in response to appropriate interventions.}, } @article {pmid37394824, year = {2023}, author = {Qais, FA and Ahmad, I and Husain, FM and Arshad, M and Khan, A and Adil, M}, title = {Umbelliferone modulates the quorum sensing and biofilm of Gram - ve bacteria: in vitro and in silico investigations.}, journal = {Journal of biomolecular structure & dynamics}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/07391102.2023.2229454}, pmid = {37394824}, issn = {1538-0254}, abstract = {In last two decades, the world has seen an exponential increase in the antimicrobial resistance (AMR), making the issue a serious threat to human health. The mortality caused by AMR is one of the leading causes of human death worldwide. Till the end of the twentieth century, a tremendous success in the discovery of new antibiotics was seen, but in last two decades, there is negligible progress in this direction. The increase in AMR combined with slow progress of antibiotic drug discovery has created an urgent demand to search for newer methods of intervention to combat infectious diseases. One of such approach is to look for biofilm and quorum sensing (QS) inhibitors. Plants are excellent source of wide class compounds that can be harnessed to look for the compounds with such properties. This study proves a broad-spectrum biofilm and QS inhibitory potential of umbelliferone. More than 85% reduction in violacein production Chromobacterium violaceum 12472 was found. All tested virulent traits of Pseudomonas aeruginosa PAO1 and Serratia marcescens MTCC 97 were remarkably inhibited that ranged from 56.62% to 86.24%. Umbelliferone also successfully prevented the biofilm of test bacteria at least by 67.68%. Umbelliferone interacted at the active site of many proteins of QS circuit, which led to the mitigation of virulent traits. The stable nature of complexes of umbelliferone with proteins further strengthens in vitro results. After examining the toxicological profile and other drug-like properties, umbelliferone could be potentially developed as new drug to target the infections caused by Gram - ve bacteria.Communicated by Ramaswamy H. Sarma.}, } @article {pmid37394468, year = {2023}, author = {Badawy, MSEM and Elkhatib, WF and Shebl, RI}, title = {Mathematical pharmacodynamic modeling for antimicrobial assessment of ceftazidime/colistin versus gentamicin/meropenem combinations against carbapenem-resistant Pseudomonas aeruginosa biofilm.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {22}, number = {1}, pages = {53}, pmid = {37394468}, issn = {1476-0711}, abstract = {BACKGROUND: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) represents an escalating healthcare hazard with high mortality worldwide, especially in presence of biofilm. The current study aimed to evaluate the anti-biofilm potentials of ceftazidime, colistin, gentamicin, and meropenem alone and in combinations against biofilm-forming CRPA.

METHODS: Biofilm killing and checkerboard assay were performed to detect the effectiveness of combined antibiotics against biofilms and planktonic cells, respectively. The bacterial bioburden retrieved from the established biofilms following treatment with combined antibiotics was utilized to construct a three-dimensional response surface plot. A sigmoidal maximum effect model was applied to determine the pharmacodynamic parameters (maximal effect, median effective concentration, and Hill factor) of each antibiotic to create a mathematical three-dimensional response surface plot.

RESULTS: Data revealed statistically significant (p < 0.05) superior anti-biofilm potential in the case of colistin followed by a lower effect in the case of gentamicin and meropenem, while ceftazidime exhibited the least anti-biofilm activity. The fractional inhibitory concentration index (FICI ≤ 0.5) indicated synergism following treatment with the combined antibiotics. An elevated anti-biofilm activity was recorded in the case of gentamicin/meropenem compared to ceftazidime/colistin. Synergistic anti-biofilm potentials were also detected via the simulated pharmacodynamic modeling, with higher anti-biofilm activity in the case of the in vitro observation compared to the simulated anti-biofilm profile.

CONCLUSIONS: The present study highlighted the synergistic potentials of the tested antibiotic combinations against P. aeruginosa biofilms and the importance of the mathematical pharmacodynamic modeling in investigating the efficacy of antibiotics in combination as an effective strategy for successful antibiotic therapy to tackle the extensively growing resistance to the currently available antibiotics.}, } @article {pmid37394375, year = {2023}, author = {Morse, R and Childers, C and Nowak, E and Rao, J and Vlaisavljevich, E}, title = {Catheter-Based Medical Device Biofilm Ablation Using Histotripsy: A Parameter Study.}, journal = {Ultrasound in medicine & biology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ultrasmedbio.2023.06.010}, pmid = {37394375}, issn = {1879-291X}, abstract = {OBJECTIVE: Biofilm formation in medical catheters is a major source of hospital-acquired infections which can produce increased morbidity and mortality for patients. Histotripsy is a non-invasive, non-thermal focused ultrasound therapy and recently has been found to be effective at removal of biofilm from medical catheters. Previously established histotripsy methods for biofilm removal, however, would require several hours of use to effectively treat a full-length medical catheter. Here, we investigate the potential to increase the speed and efficiency with which biofilms can be ablated from catheters using histotripsy.

METHODS: Pseudomonas aeruginosa (PA14) biofilms were cultured in in vitro Tygon catheter mimics and treated with histotripsy using a 1 MHz histotripsy transducer and a variety of histotripsy pulsing rates and scanning methods. The improved parameters identified in these studies were then used to explore the bactericidal effect of histotripsy on planktonic PA14 suspended in a catheter mimic.

RESULTS: Histotripsy can be used to remove biofilm and kill bacteria at substantially increased speeds compared with previously established methods. Near-complete biofilm removal was achieved at treatment speeds up to 1 cm/s, while a 4.241 log reduction in planktonic bacteria was achieved with 2.4 cm/min treatment.

CONCLUSION: These results represent a 500-fold increase in biofilm removal speeds and a 6.2-fold increase in bacterial killing speeds compared with previously published methods. These findings indicate that histotripsy shows promise for the treatment of catheter-associated biofilms and planktonic bacteria in a clinically relevant time frame.}, } @article {pmid37393048, year = {2023}, author = {Zhang, X and Wang, T and Ma, W and Bi, L}, title = {The study on the effect of amino acid porphyrin conjugate-mediated antimicrobial photodynamic therapy on Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {}, number = {}, pages = {103684}, doi = {10.1016/j.pdpdt.2023.103684}, pmid = {37393048}, issn = {1873-1597}, abstract = {Antimicrobial Photodynamic Therapy (aPDT) based on the action of visible light and photosensitizers has emerged as a promising microbial reduction and alternative to antibiotics resistance to cariogenic pathogens. The present research aims to evaluate the antimicrobial effect of aPDT mediated by a new photosensitizer (amino acid porphyrin conjugate 4i) on Streptococcus mutans (S. mutans) biofilm. Qualitative morphologic characteristics of S. mutans biofilms are shown by scanning electron microscopy (SEM). The colony plate counting method is used to measure the dark toxicity and the phototoxicity of different concentrations of 4i-aPDT to S. mutans biofilms. MTT assay is conducted to investigate the effect of 4i mediated aPDT on the metabolic activity of S. mutans biofilm. Changes in structure morphology, bacterial density and extracellular matrix of S. mutans biofilm are observed by SEM. The distribution of living and dead bacteria in biofilm is detected using Confocal laser microscopy (CLSM). The results indicate that single laser irradiation has no antibacterial effect on S. mutans biofilms. With the increase of 4i concentration or the prolongation of laser irradiation time, the antibacterial effect of 4i-mediated aPDT on S. mutans biofilm is more statistically significant compared to the control. When the concentration of 62.5 μmol/L 4i is continuously illuminated for 10 minutes, the logarithm of the colonies in the biofilm shows a reduction of 3.4 log10. MTT assay detected absorbance values of biofilm by 4i-mediated aPDT are the lowest, indicating a significant decrease in biofilm metabolic activity. SEM analysis shows that 4i mediated aPDT reduced the quantity and density of S. mutans. A dense red fluorescence image of the 4i-aPDT treated biofilm is observed under CLSM, indicating that the dead bacteria are widely distributed.}, } @article {pmid37392965, year = {2023}, author = {Luan, YN and Xu, Y and Guo, Z and Yin, Y and Wang, Q and Zhang, F and Xiao, Y and Liu, C and Jiang, S}, title = {Enhanced nitrogen removal in immersed rotating self-aerated biofilm reactor: nitrogen removal pathway and microbial mechanism.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129426}, doi = {10.1016/j.biortech.2023.129426}, pmid = {37392965}, issn = {1873-2976}, abstract = {To achieve energy-efficient treatment of the rural wastewater with satisfying performance, a novel immersed rotating self-aerated biofilm reactor (iRSABR) was proposed in this study. The iRSABR system showed better biofilm renewal performance and higher microbial activity. The effect of different regulation strategies on the iRSABR system was investigated in this study. The 70% immersion ratio and 4 r/min rotation speed (stage III) exhibited the best performance, with a total nitrogen removal efficiency of 86% and a simultaneous nitrification-denitrification (SND) rate of 76%, along with the highest electron transport system activity. The nitrogen removal pathway revealed that the SND was achieved through autotrophic/heterotrophic nitrification and aerobic/anoxic denitrification. The regulation strategy in the iRSABR system established a synergistic microbial community with main functional bacteria of nitrification (Nitrosomonas), anoxic denitrification (Flavobacterium, Pseudoxanthomonas), and aerobic denitrification (Thauera). This study highlighted the feasibility and adaptability of the iRSABR system toward energy-efficient rural wastewater treatment.}, } @article {pmid37392924, year = {2023}, author = {Garg, SS and Dubey, R and Sharma, S and Vyas, A and Gupta, J}, title = {Biological macromolecules-based nanoformulation in improving wound healing and bacterial biofilm-associated infection: A review.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {125636}, doi = {10.1016/j.ijbiomac.2023.125636}, pmid = {37392924}, issn = {1879-0003}, abstract = {A chronic wound is a serious complication associated with diabetes mellitus and is difficult to heal due to high glucose levels, oxidative stress, and biofilm-associated microbial infection. The structural complexity of microbial biofilm makes it impossible for antibiotics to penetrate the matrix, hence conventional antibiotic therapies became ineffective in clinical settings. This demonstrates an urgent need to find safer alternatives to reduce the prevalence of chronic wound infection associated with microbial biofilm. A novel approach to address these concerns is to inhibit biofilm formation using biological-macromolecule based nano-delivery system. Higher drug loading efficiency, sustained drug release, enhanced drug stability, and improved bioavailability are advantages of employing nano-drug delivery systems to prevent microbial colonization and biofilm formation in chronic wounds. This review covers the pathogenesis, microbial biofilm formation, and immune response to chronic wounds. Furthermore, we also focus on macromolecule-based nanoparticles as wound healing therapies to reduce the increased mortality associated with chronic wound infections.}, } @article {pmid37390895, year = {2023}, author = {Huang, H and He, J and Gao, X and Lei, J and Zhang, Y and Wang, Y and Liu, X and Hao, J}, title = {Mechanism of acid and alkali electrolyzed water on the elimination of Listeria monocytogenes biofilm based on proteomic analysis.}, journal = {Journal of proteomics}, volume = {}, number = {}, pages = {104952}, doi = {10.1016/j.jprot.2023.104952}, pmid = {37390895}, issn = {1876-7737}, abstract = {Acidic electrolyzed water is a relatively mature bactericide, which has a certain inhibitory effect on a variety of microorganisms, and is widely used in the field of food processing for cleaning, sterilization and disinfection. This study investigated the deactivation mechanisms of Listeria monocytogenes by Tandem Mass Tags quantitative proteomics analysis. Samples were treated through A1S4 (Alkaline electrolytic water treatment for 1 min and Acid electrolytic water treatment for 4 min), S3A1S1 (Acid electrolyzed water treatment 3 min, Alkaline electrolyzed water treatment 1 min and Acid electrolyzed water treatment 1 min), S5 (Acid electrolytic water treatment for 5 min). Proteomic analysis showed that the mechanism of acid alkaline electrolyzed water treatment to eliminate the inactivation of the biofilm of L. monocytogenes was related to protein transcription and extension, RNA processing and synthesis, gene regulation, sugar and amino acid transport and metabolism, signal transduction and ATP binding. The study on the influence mechanism and action mechanism of the combination of acidic and alkaline electrolyzed water to remove L. monocytogenes biofilm is helpful to understand the development of the process of removing biofilm by electrolyzed water, and provides theoretical support for the treatment of other microbial contamination problems in food processing by electrolyzed water.}, } @article {pmid37390118, year = {2023}, author = {Deiss-Yehiely, E and Cárcamo-Oyarce, G and Berger, AG and Ribbeck, K and Hammond, PT}, title = {pH-Responsive, Charge-Reversing Layer-by-Layer Nanoparticle Surfaces Enhance Biofilm Penetration and Eradication.}, journal = {ACS biomaterials science & engineering}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsbiomaterials.3c00481}, pmid = {37390118}, issn = {2373-9878}, abstract = {Microbes entrenched within biofilms can withstand 1000-fold higher concentrations of antibiotics, in part due to the viscous extracellular matrix that sequesters and attenuates antimicrobial activity. Nanoparticle (NP)-based therapeutics can aid in delivering higher local concentrations throughout biofilms as compared to free drugs alone, thereby enhancing the efficacy. Canonical design criteria dictate that positively charged nanoparticles can multivalently bind to anionic biofilm components and increase biofilm penetration. However, cationic particles are toxic and are rapidly cleared from circulation in vivo, limiting their use. Therefore, we sought to design pH-responsive NPs that change their surface charge from negative to positive in response to the reduced biofilm pH microenvironment. We synthesized a family of pH-dependent, hydrolyzable polymers and employed the layer-by-layer (LbL) electrostatic assembly method to fabricate biocompatible NPs with these polymers as the outermost surface. The NP charge conversion rate, dictated by polymer hydrophilicity and the side-chain structure, ranged from hours to undetectable within the experimental timeframe. LbL NPs with an increasingly fast charge conversion rate more effectively penetrated through, and accumulated throughout, wildtype (PAO1) and mutant overexpressing biomass (ΔwspF) Pseudomonas aeruginosa biofilms. Finally, tobramycin, an antibiotic known to be trapped by anionic biofilm components, was loaded into the final layer of the LbL NP. There was a 3.2-fold reduction in ΔwspF colony forming units for the fastest charge-converting NP as compared to both the slowest charge converter and free tobramycin. These studies provide a framework for the design of biofilm-penetrating NPs that respond to matrix interactions, ultimately increasing the efficacious delivery of antimicrobials.}, } @article {pmid37389797, year = {2023}, author = {Rana, S and Upadhyay, LSB}, title = {Utilization of non-pathogenic bacteria to obtain optimum biofilm production for beneficial applications.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37389797}, issn = {1678-4405}, abstract = {Depending on the bacteria embedded in the extracellular polymeric layer, biofilms can be advantageous or harmful. The isolated strains used in this investigation are already established to be beneficial biofilm-producing bacteria. In order to use them effectively in various domains, it is necessary to characterize them and understand their ideal physiological characteristics for maximum biofilm growth. This study used genome sequence analysis to identify and characterize strains isolated from water samples in Raipur, Chhattisgarh, India. The nucleotide sequences were submitted to NCBI GenBank under the accession numbers Bacillus tequilensis (MN889418) and Pseudomonas beteli (MN889419) and the strains were further characterized using some advanced techniques (phase contrast microscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscope). For maximum biofilm formation by isolated bacterial strains, many physiochemical factors including incubation duration, temperature, pH, carbon source concentration, and nitrogen source concentration were further examined and optimized. The fact that these non-pathogenic strains were found in public water supplies is another important part of this research because there is a chance that they could change into pathogenic state in future and cause disease in humans.}, } @article {pmid37389724, year = {2023}, author = {Das, S and Roy, R and Paul, P and Chakraborty, P and Chatterjee, S and Malik, M and Sarkar, S and Das Gupta, A and Maiti, D and Tribedi, P}, title = {Piperine, a Plant Alkaloid, Exhibits Efficient Disintegration of the Pre-existing Biofilm of Staphylococcus aureus: a Step Towards Effective Management of Biofilm Threats.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37389724}, issn = {1559-0291}, support = {R&D/2020/F2//The Neotia University/ ; }, abstract = {Staphylococcus aureus causes a range of chronic infections in humans by exploiting its biofilm machinery and drug-tolerance property. Although several strategies have been proposed to eradicate biofilm-linked issues, here, we have explored whether piperine, a bioactive plant alkaloid, can disintegrate an already existing Staphylococcal biofilm. Towards this direction, the cells of S. aureus were allowed to develop biofilm first followed by treatment with the test concentrations (8 and 16 µg/mL) of piperine. In this connection, several assays such as total protein recovery assay, crystal violet assay, extracellular polymeric substances (EPS) measurement assay, fluorescein diacetate hydrolysis assay, and fluorescence microscopic image analysis confirmed the biofilm-disintegrating property of piperine against S. aureus. Piperine reduced the cellular auto-aggregation by decreasing the cell surface hydrophobicity. On further investigation, we observed that piperine could down regulate the dltA gene expression that might reduce the cell surface hydrophobicity of S. aureus. It was also observed that the piperine-induced accumulation of reactive oxygen species (ROS) could enhance biofilm disintegration by decreasing the cell surface hydrophobicity of the test organism. Together, all the observations suggested that piperine could be used as a potential molecule for the effective management of the pre-existing biofilm of S. aureus.}, } @article {pmid37389370, year = {2023}, author = {Lejay, A and Chakfé, N}, title = {Biofilm is the Target: Commentary on: "A Narrative Review of Experimental Assessment to Study Vascular Biomaterials Infection and Infectability".}, journal = {EJVES vascular forum}, volume = {59}, number = {}, pages = {22-23}, doi = {10.1016/j.ejvsvf.2023.04.003}, pmid = {37389370}, issn = {2666-688X}, } @article {pmid37388456, year = {2023}, author = {Konieczka, P and Ferenc, K and Jørgensen, JN and Hansen, LHB and Zabielski, R and Olszewski, J and Gajewski, Z and Mazur-Kuśnirek, M and Szkopek, D and Szyryńska, N and Lipiński, K}, title = {Feeding Bacillus-based probiotics to gestating and lactating sows is an efficient method for improving immunity, gut functional status and biofilm formation by probiotic bacteria in piglets at weaning.}, journal = {Animal nutrition (Zhongguo xu mu shou yi xue hui)}, volume = {13}, number = {}, pages = {361-372}, doi = {10.1016/j.aninu.2023.03.003}, pmid = {37388456}, issn = {2405-6383}, abstract = {The effects of dietary probiotic supplementation with viable Bacillus subtilis and Bacillus amyloliquefaciens spores on sow performance, immunity, gut functional status and biofilm formation by probiotic bacteria in piglets at weaning were investigated. Ninety-six sows reared in a continuous farrowing system for one full cycle were fed gestation diets during the first 90 d of pregnancy and lactation diets until the end of lactation. The sows were fed a basal diet without probiotics (control; n = 48) or a diet supplemented with viable spores (1.1 × 10[9] CFU/kg of feed) (probiotic; n = 48). At 7 d of age, sucking piglets (n = 12/group) were provided prestarter creep feed until weaning at 28 d of age. The piglets in the probiotic group were supplemented with the same probiotic and dosage as their dams. Blood and colostrum collected from sows and ileal tissues collected from piglets on the day of weaning were used for analyses. Probiotics increased the weight of piglets (P = 0.077), improved the weaning weight (P = 0.039) and increased both the total creep feed consumption (P = 0.027) and litter gain (P = 0.011). Probiotics also improved the faecal score in the second (P = 0.013) week of life. The immunoglobulin G (IgG) concentrations in sow blood at farrowing and the IgM concentrations in piglet blood at weaning were higher in the probiotic group than in the control group (P = 0.046). The piglets from the probiotic-treated sows showed a higher IgM concentration in the ileal mucosa (P = 0.050) and a lower IgG concentration in the ileal mucosa (P = 0.021) compared with the piglets from control sows. The probiotic-treated piglets had a thicker ileal mucosa (P = 0.012) due to the presence of longer villi and larger Peyer's patches (P < 0.001). B. subtilis and B. amyloliquefaciens were detected in the probiotic-treated piglets but not the control piglets; these bacteria were present in the digesta and villus structures and formed structures resembling biofilms. Overall, Bacillus-based probiotic supplementation improves the health indices of sows and their piglets.}, } @article {pmid37388199, year = {2023}, author = {Reyhani, MF and Ghasemi, N and Milani, AS and Abbasi Asl, M}, title = {Antimicrobial Effect of Nano-Calcium Hydroxide on the Four- and Six-Week-Old Intra-Canal Enterococcus Faecalis Biofilm.}, journal = {Journal of dentistry (Shiraz, Iran)}, volume = {24}, number = {2}, pages = {194-199}, doi = {10.30476/dentjods.2022.94792.1812}, pmid = {37388199}, issn = {2345-6485}, abstract = {STATEMENT OF THE PROBLEM: Enterococcus faecalis (E. faecalis) is one of the most important microorganisms in the evaluation of the antibacterial effects of intra-canal medications due to its ability to penetrate dentinal tubules and form biofilms. Calcium hydroxide, as the most common intra-canal medication, has little effect on this bacterial species. In contrast, it is hypothesized that nano scale hydroxide particles are more effective due to their smaller size and higher surface-to-volume ratio.

PURPOSE: This study aimed to investigate the antimicrobial effect of nano-calcium hydroxide on the four- and six-week-old intra-canal E. faecalis biofilms.

MATERIALS AND METHOD: In this in vitro study, seventy maxillary single-canal premolar teeth were used. After cleaning and preparing the root canals, the samples were placed in vials containing E. faecalis solution in which the culture medium was changed daily. Each group was divided into three subgroups (n=20) in terms of the antimicrobial material used as the intra-canal medication including subgroup 1: nano-calcium hydroxide, subgroup 2: calcium hydroxide, and subgroup 3: phosphate-buffered saline solution (control group). The antimicrobial property was measured by counting colony-forming units (CFU). The data were analyzed with Mann-Whitney U and Kruskal-Wallis tests. Statistical significance was set at p< 0.05.

RESULTS: The mean CFU in the six-week-old biofilm group was significantly higher than that in the four-week-old biofilm (p= 0.003). A comparison between the subgroups showed a significant decrease in CFU in the six-week-old biofilm in the nano-calcium hydroxide subgroup compared to that in the calcium hydroxide subgroup (p= 0.002). However, the decrease was not significant in the four-week-old biofilm group (p= 0.06).

CONCLUSION: Under the limitations of the present study, the antimicrobial properties of nano-calcium hydroxide were higher than conventional calcium hydroxide on mature biofilm, whereas the antimicrobial properties were not clinically and significantly different on immature biofilm.}, } @article {pmid37387577, year = {2023}, author = {Gu Liu, C and Maresso, AW}, title = {Effect of various types of extracellular DNA on V. hyugaensis biofilm formation.}, journal = {mSphere}, volume = {}, number = {}, pages = {e0003523}, doi = {10.1128/msphere.00035-23}, pmid = {37387577}, issn = {2379-5042}, abstract = {Marine bacteria face a constant influx of new extracellular DNA (exDNA) due to the massive viral lysis that occurs in the ocean on a daily basis. Generally, biofilms have shown to be induced by self-secreted exDNA. However, the effect of various types of exDNA with varying lengths, self vs non-self, as well as guanine-cytosine content (GC) content on biofilm formation has not been explored, despite being a critical component of the extracellular polymeric substance. To test the effect of such exDNA on biofilms, a marine bioluminescent bacterium (Vibrio hyugaensis) was isolated from the Sippewissett Salt Marsh, USA, and treated with various types of exDNA. We observed rapid pellicle formation with distinct morphologies only in cultures treated with herring sperm gDNA, another Vibrio spp. gDNA, and an oligomer of 61-80% GC content. With pH measurements before and after the treatment, we observed a positive correlation between biofilm formation and the change to a more neutral pH. Our study highlights the importance of studying DNA-biofilm interaction by carefully examining the physical properties of the DNA and by varying its content, length, and source. Our observation may serve as the basis for future studies that seek to interrogate the molecular explanation for the various types of exDNA and their effects on biofilm formation. IMPORTANCE Bacteria mostly exist as biofilm, a protective niche that promotes protection from the environment and nutrient uptake. By forming these structures, bacteria have caused recalcitrant antibiotic-resistant infections, contamination of dairy and seafood, and fouling equipment in the industry. A critical component that makes up the extracellular polymeric substances, the structural component of a biofilm, is the extracellular DNA secreted by the bacteria found in the biofilm. However, previous studies on DNA and biofilm formation have neglected the unique properties of nucleic acid and its high diversity. Our study aims at disentangling these DNA properties by monitoring their effect at inducing biofilm formation. By varying length, self vs non-self, and GC percentage, we used various microscopy techniques to visualize the structural composition of a Vibrio hyugaensis biofilm. We observed DNA-dependent biofilm stimulation in this organism, a novel function of DNA in biofilm biology.}, } @article {pmid37385560, year = {2023}, author = {Wang, B and Zhan, Q and Xiao, Y and Xu, Y and Zhao, H and Rao, L and Wang, X and Zhang, J and Shen, L and Zhou, Y and Guo, Y and Wu, X and Yu, J and Yu, F}, title = {Mupirocin enhances the biofilm formation of Staphylococcus epidermidis in an atlE-dependent manner.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106904}, doi = {10.1016/j.ijantimicag.2023.106904}, pmid = {37385560}, issn = {1872-7913}, abstract = {The pathogenicity of Staphylococcus epidermidis is largely attributed to its exceptional ability to form biofilms. Here, we report that mupirocin, an antimicrobial agent widely used for staphylococcal decolonization and anti-infection, strongly stimulates the biofilm formation of S. epidermidis. Although the polysaccharide intercellular adhesin (PIA) production was unaffected, mupirocin significantly facilitated extracellular DNA (eDNA) release by accelerating autolysis, thereby positively triggering cell surface attachment and intercellular agglomeration during biofilm development. Mechanistically, mupirocin regulated the expression of genes encoding for the autolysin AtlE as well as the programmed cell death system CidA-LrgAB. Critically, through gene knockout, we found out that deletion of atlE, but not cidA or lrgA, abolished the enhancement of biofilm formation and eDNA release in response to mupirocin treatment, indicating that atlE is required for this effect. In Triton X-100 induced autolysis assay, mupirocin treated atlE mutant displayed a slower autolysis rate compared with the wild-type strain and complementary strain. Therefore, we concluded that subinhibitory concentrations of mupirocin enhance the biofilm formation of S. epidermidis in an atlE dependent manner. This induction effect could conceivably be responsible for some of the more unfavorable outcomes of infectious diseases.}, } @article {pmid37385200, year = {2023}, author = {Du, Y and Zhou, W and Zhang, L and Liu, X}, title = {Gravity-driven membrane coupled with oxidation technology to modify the surface properties and biofilm formation: Biofouling mitigation.}, journal = {Journal of environmental management}, volume = {345}, number = {}, pages = {118444}, doi = {10.1016/j.jenvman.2023.118444}, pmid = {37385200}, issn = {1095-8630}, abstract = {Biofilms caused by biological fouling play an essential role in gravity-driven membranes' (GDMs) flux decline and rejection rate. The effects of ozone, permanganate, and ferrate (VI) in-situ pretreatment on membrane properties and biofilm formation were systematically studied. Due to the selective retention and adsorption of algal organic matter by biofilms and oxidative degradation, the rejection efficiency of dissolved organic carbon (DOC) in algae-laden water pretreated with permanganate by GDM was up to 23.63%. Pre-oxidation extraordinarily postponed flux decline and biofilm formation of GDM and reduced membrane fouling. The total membrane resistance decreased by 87.22%-90.30% within 72 h after pre-ozonation. Permanganate was more effective than ozone and ferrate (VI) in alleviating secondary membrane fouling caused by algal cells destroyed by pre-oxidation. Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory revealed that the distribution of electrostatic force (EL), acid-base (AB), and Lifshitz-van der Waals forces (LW) interactions between M. aeruginosa and the released intracellular algogenic organic matter (IOM) and ceramic membrane surface was similar. The membrane and foulants are always attracted to each other by LW interaction at different separation distances. The dominant fouling mechanism of GDM combined with pre-oxidation technology shifts from complete pore blocking to cake layer filtration during operation. After pre-oxidation of algae-laden water by ozone, permanganate, and ferrate (VI), GDM can treat at least 131.8%, 37.0%, and 61.5% more feed solution before forming a complete cake layer. This study provides new insights into the biological fouling control strategies and mechanisms for GDM coupled with oxidation technology, which is expected to alleviate membrane fouling and optimize the feed liquid pretreatment procedure.}, } @article {pmid37386135, year = {2023}, author = {Harding, CJ and Bischoff, M and Bergkessel, M and Czekster, CM}, title = {An anti-biofilm cyclic peptide targets a secreted aminopeptidase from P. aeruginosa.}, journal = {Nature chemical biology}, volume = {}, number = {}, pages = {}, pmid = {37386135}, issn = {1552-4469}, support = {210486/Z/18/Z//Wellcome Trust (Wellcome)/ ; 210486/Z/18/Z//Wellcome Trust (Wellcome)/ ; 204816/Z/16/Z//Wellcome Trust (Wellcome)/ ; MR/T041811///RCUK | Medical Research Council (MRC)/ ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes serious illness, especially in immunocompromised individuals. P. aeruginosa forms biofilms that contribute to growth and persistence in a wide range of environments. Here we investigated the aminopeptidase, P. aeruginosa aminopeptidase (PaAP) from P. aeruginosa, which is highly abundant in the biofilm matrix. PaAP is associated with biofilm development and contributes to nutrient recycling. We confirmed that post-translational processing was required for activation and PaAP is a promiscuous aminopeptidase acting on unstructured regions of peptides and proteins. Crystal structures of wild-type enzymes and variants revealed the mechanism of autoinhibition, whereby the C-terminal propeptide locks the protease-associated domain and the catalytic peptidase domain into a self-inhibited conformation. Inspired by this, we designed a highly potent small cyclic-peptide inhibitor that recapitulates the deleterious phenotype observed with a PaAP deletion variant in biofilm assays and present a path toward targeting secreted proteins in a biofilm context.}, } @article {pmid37382659, year = {2023}, author = {Fan, L and Liu, Z and Zhang, Z and Bai, H}, title = {Antimicrobial Effects of Sophora flavescens Alkaloids on Metronidazole-Resistant Gardnerella vaginalis in Planktonic and Biofilm Conditions.}, journal = {Current microbiology}, volume = {80}, number = {8}, pages = {263}, pmid = {37382659}, issn = {1432-0991}, support = {No.XKDTR201803//Beijing Obstetrics and Gynecology Hospital, Capital Medical University/ ; }, abstract = {Bacterial vaginosis (BV) is a common infectious disease of the lower female reproductive tract, which is characterized by the augmentation of anaerobic bacteria. Gardnerella (G.) vaginalis plays a predominant role in BV recurrence relating to its higher virulence potential and biofilm formation ability. With the increased proportion of metronidazole-resistant G. vaginalis, controlling resistance to metronidazole and finding more effective drugs became a major concern. In this study, 30 clinical strains were cultured from the vaginal secretions of BV patients, followed by PCR and 16S rDNA sequencing identification. According to the CLSI guidelines for anaerobic drug sensitivity testing, 19 strains were identified as metronidazole-resistant (minimum inhibitory concentration, MIC ≥ 32 μg/mL), of which 4 clinical strains were observed to be strong biofilm producer and the final minimum biofilm inhibitory concentration (MBIC) of metronidazole was increased to 512 μg/mL. Sophora flavescens Alkaloids (SFAs), a traditional chinese medicine, could not only inhibit the growth of metronidazole-resistant G. vaginalis in planktonic (MIC: 0.3125-1.25 mg/mL), but also eliminate the biofilm formation (MBIC: 0.625-1.25 mg/mL). In the high-magnification scanning electron, it was observed that the morphology of biofilm changed from a thick to flaky shape and was nearly depleted. These results indicate that SFAs could not only inhibit the growth of metronidazole-resistant G. vaginalisin planktonic and biofilm levels, but also destroyed the biofilm morphology and microstructure, which may contribute to the prevention of BV recurrence.}, } @article {pmid37382537, year = {2023}, author = {Cheah, H and Bae, S}, title = {Multichannel Microfluidic Platform for Temporal-Spatial Investigation of Niche Roles of Pseudomonas aeruginosa and Escherichia coli within a Dual-Species Biofilm.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0065123}, doi = {10.1128/aem.00651-23}, pmid = {37382537}, issn = {1098-5336}, abstract = {In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. In this study, a microfluidic device designed with multiple channels and a gradient generator was used for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. We compared the structural parameters of monospecies and dual-species biofilms containing Pseudomonas aeruginosa (expressing mCherry) and Escherichia coli (expressing green fluorescent protein [GFP]) to understand the interactions in the biofilm. The rate of biovolume increase of each species in monospecies biofilm (2.7 × 10[5] μm[3]) was higher than those in a dual-species biofilm (9.68 × 10[4] μm[3]); however, synergism was still observed in the dual-species biofilm due to overall increases in biovolume for both species. Synergism was also observed in a dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. The microfluidic chip was useful for monitoring the dual-species biofilm in the microenvironment, indicating that different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. Finally, we demonstrated that the nucleic acids can be extracted from the dual-species biofilm in situ after biofilm imaging analysis. In addition, gene expression supported that the activation and suppression of different quorum sensing genes resulted in the different phenotype seen in the biofilm. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously. IMPORTANCE In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. Here, we demonstrate that a microfluidic device with multiple channels and a gradient generator can be useful for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. Our study revealed synergism in the dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. Furthermore, different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously.}, } @article {pmid37382505, year = {2023}, author = {Ugya, AY and Chen, H and Wang, Q}, title = {Microalgae biofilm system as an efficient tool for wastewater remediation and potential bioresources for pharmaceutical product production: an overview.}, journal = {International journal of phytoremediation}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/15226514.2023.2229920}, pmid = {37382505}, issn = {1549-7879}, abstract = {The role of microalgae in wastewater remediation and metabolite production has been well documented, but the limitations of microalgae harvesting and low biomass production call for a more sustainable method of microalgae utilization. The current review gives an insight on how microalgae biofilms can be utilized as a more efficient system for wastewater remediation and as potential source of metabolite for pharmaceutical product production. The review affirms that the extracellular polymeric substance (EPS) is the vital component of the microalgae biofilm because it influences the spatial organization of the organisms forming microalgae biofilm. The EPS is also responsible for the ease interaction between organisms forming microalgae biofilm. This review restate the crucial role play by EPS in the removal of heavy metals from water to be due to the presence of binding sites on its surface. This review also attribute the ability of microalgae biofilm to bio-transform organic pollutant to be dependent on enzymatic activities and the production of reactive oxygen species (ROS). The review assert that during the treatment of wastewater, the wastewater pollutants induce oxidative stress on microalgae biofilms. The response of the microalgae biofilm toward counteracting the stress induced by ROS leads to production of metabolites. These metabolites are important tools that can be harness for the production of pharmaceutical products.}, } @article {pmid37380159, year = {2023}, author = {Sadighnia, N and Arfaee, F and Tavakoli, A and Jahandideh, A}, title = {Dextranase enzyme and Enterococcus faecium probiotic have anti-biofilm effects by reducing the count of bacteria in dental plaque in the oral cavity of dogs.}, journal = {Journal of the American Veterinary Medical Association}, volume = {}, number = {}, pages = {1-6}, doi = {10.2460/javma.23.03.0162}, pmid = {37380159}, issn = {1943-569X}, abstract = {OBJECTIVE: Periodontal disease is a common clinical complication and has a negative impact on the quality of life and the welfare of companion dogs. Periodontal disease occurs when pathogenic bacteria are accumulated in the gingival sulcus, which favors biofilm formation. The oral health of dogs can be significantly compromised by dental plaque accumulation. Thus, this investigation demonstrates the effect of Enterococcus faecium probiotic, dextranase enzyme, and their combination on dental biofilm in the oral cavity of dogs.

ANIMALS: The 30 dogs were referred to Polyclinic with no oral ulcers, severe periodontitis, and internal diseases.

PROCEDURES: Dextranase enzyme, E faecium probiotic, and their combination were administered in the oral cavity of dogs. Microbiological samples were obtained from tooth surfaces and gums before and after intervention with the substances. Bacterial colonies were enumerated by using a colony counter. Also, Porphyromonas gingivalis hmuY gene expression was evaluated by reverse transcription quantitative real-time PCR analysis.

RESULTS: The total colony count of the bacterial culture indicated that the dextranase enzyme, E faecium probiotic, and their combination significantly reduced the total bacteria count in the oral cavity. Moreover, in the reverse transcription quantitative real-time PCR analysis it was observed that using the combination of E faecium probiotic and dextranase enzyme decreases the hmuY gene expression of P gingivalis bacteria.

CLINICAL RELEVANCE: The results clearly indicated that the dextranase enzyme and E faecium probiotic could be used as preventive agents to reduce oral biofilm in dogs. Furthermore, no side effects were observed while using these substances.}, } @article {pmid37379952, year = {2023}, author = {Elmehbad, NY and Mohamed, NA and Abd El-Ghany, NA and Abdel-Aziz, MM}, title = {Reinforcement of the antimicrobial activity and biofilm inhibition of novel chitosan-based hydrogels utilizing zinc oxide nanoparticles.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {125582}, doi = {10.1016/j.ijbiomac.2023.125582}, pmid = {37379952}, issn = {1879-0003}, abstract = {Two novel chemically cross-linked chitosan hydrogels were successfully prepared via insertion of oxalyl dihydrazide moieties between chitosan Schiff's base chains (OCsSB) and between chitosan chains (OCs). For more modification, two different concentrations of ZnO nanoparticles (ZnONPs) were loaded into OCs to obtain OCs/ZnONPs-1 % and OCs/ZnONPs-3 % composites. The prepared samples were recognized using elemental analyses, FTIR, XRD, SEM, EDS and TEM. Their inhibitory action against microbes and biofilms were classified as: OCs/ZnONPs-3 % > OCs/ZnONPs-1 % > OCs > OCsSB > chitosan. OCs has inhibition activity similar to Vancomycin of minimum inhibitory concentration (MIC) value of 3.9 μg/mL against P. aeruginosa. OCs exhibited minimum biofilm inhibitory concentration (MBIC) values (from 31.25 to 62.5 μg/mL) less than that of OCsSB (from 62.5 to 250 μg/mL) which lower than that of chitosan (from 500 to 1000 μg/mL) against S. epidermidis, P. aeruginosa and C. albicans. OCs/ZnNPs-3 % showed MIC value (that caused 100 % inhibition of Clostridioides difficile, C. difficile) of 0.48 μg/mL much lower than Vancomycin (1.95 μg/mL). Both OCs and OCs/ZnONPs-3 % composite were safe on normal human cells. Thus, inclusion of oxalyl dihydrazide and ZnONPs into chitosan greatly reinforced its antimicrobial activity. This is a good strategy to accomplish adequate systems for competing traditional antibiotics.}, } @article {pmid37380794, year = {2023}, author = {Zhu, X and von Werdt, L and Zappalà, G and Sculean, A and Eick, S and Stähli, A}, title = {In vitro activity of hyaluronic acid and human serum on periodontal biofilm and periodontal ligament fibroblasts.}, journal = {Clinical oral investigations}, volume = {}, number = {}, pages = {}, pmid = {37380794}, issn = {1436-3771}, abstract = {OBJECTIVES: A beneficial effect of cross-linked hyaluronic acid (cHA) on periodontal wound healing and regeneration has recently been demonstrated. The present in vitro study was designed to obtain deeper knowledge on the effect of cHA when applied in the gingival sulcus (serum-rich environment) during non-surgical periodontal therapy.

MATERIALS AND METHODS: The influence of cHA, human serum (HS), and cHA/HS on (i) a 12-species biofilm formation, (ii) the adhesion of periodontal ligament fibroblasts (PDLF) to dentine surface, (iii) the expression and secretion of interleukin-8, and (iv) the expression of receptors of HA in PDLF and gingival fibroblasts (GF) were evaluated.

RESULTS: At 4 h of biofilm formation, cHA and HS in combination (cHA/HS) slightly decreased the colony-forming unit counts in biofilm whereas the metabolic activity of biofilm was reduced in all test groups (cHA, HS, cHA/HS) vs. control. At 24 h, the quantity of biofilm was reduced in all test groups vs. untreated control. The test substances did not affect adhesion of PDLF to dentin. HS increased the expression of IL-8 by PDLF and GF which was partially downregulated by cHA. HS and/or cHA promoted the expression of the HA receptor RHAMM in GF but not in PDLF.

CONCLUSIONS: In summary, the present data indicate that serum neither negatively affect the activity of cHA against periodontal biofilm nor had any unwanted influence on the activity of PDLF.

CLINICAL RELEVANCE: These findings lend additional support for the positive effects of cHA on cells involved in periodontal wound healing, thus pointing to its potential use in non-surgical periodontal therapy.}, } @article {pmid37379574, year = {2023}, author = {Wu, J and Li, X and Kong, R and Wang, J and Wang, X}, title = {Analysis of biofilm expansion rate of Bacillus subtilis MTC871 on agar substrates with different stiffness.}, journal = {Canadian journal of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1139/cjm-2022-0259}, pmid = {37379574}, issn = {1480-3275}, abstract = {The surface morphology of mature biofilms is heterogeneous and can be divided into concentric rings wrinkles (I), labyrinthine networks wrinkles (II), radial ridges wrinkles(III) and branches wrinkles (IV), according to surface wrinkle structure and distribution characteristics. Due to the wrinkle structures, channels are formed between the biofilm and substrate and transport nutrients, water, metabolic products, etc. We find that expansion rate variations of biofilms growing on substrates with high and low agar concentration (1.5wt%, 2.0wt%,2.5wt%) are not in the same phase. In the first three days' growth, the interaction stress between biofilm and each agar substrate increases, which makes the biofilm expansion rate decreases before wrinkle pattern IV (branches) comes up. After three days, in the later growth stage after wrinkle pattern IV appears, the biofilm has larger expansion rate growing on 2.0wt% agar concentration, which has the larger wrinkle distance in wrinkle pattern IV reducing energy consumption. Our study shows that the stiff substrate does not always inhibit the biofilm expansion, although it does in the earlier stage, after that, mature biofilms acquire larger expansion rate by adjusting the growth mode through the wrinkle evolution even in nutrient extremely depletion.}, } @article {pmid37378742, year = {2023}, author = {Rahimi, M and Piroozmand, A and Shayestehpour, M and Salamat, S and Peik Falak, F and Shakerimoghaddam, A and Moosavi, GA and Khaledi, A}, title = {Effect of curcumin nanoparticles and alcoholic extract of Falcaria vulgaris on the growth rate, biofilm, and gene expression in Pseudomonas aeruginosa isolated from burn wound infection.}, journal = {Molecular biology reports}, volume = {}, number = {}, pages = {}, pmid = {37378742}, issn = {1573-4978}, support = {99103//Kashan University of Medical Sciences/ ; }, abstract = {PURPOSE: This study aimed to investigate the effect of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris on the growth rate, biofilm, and gene expression in Pseudomonas aeruginosa isolated from burn wound infection.

METHODS: The alcoholic extract of Falcaria vulgaris was purchased from Pasargad Company. Curcumin nanoparticles were synthesized. Antibacterial activity of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris was investigated by microdilution method alone and in combination. Biofilm inhibitory was investigated by microtitrplate method. Effect of Curcumin nanoparticles and alcoholic extract of Falcaria vulgaris were evaluated on algD gene expression via Real-Time PCR. Cytotoxicity was evaluated by MTT assay on HDF cell line. Then, the data were analyzed using SPSS software.

RESULTS: Synthesized Curcumin nanoparticles were approved by Fourier Transform Infrared (FTIR), and Scanning Electron Microscope. The alcoholic extract of Falcaria Vulgaris showed significant antibacterial activity against multidrug resistance (MDR) P. aeruginosa isolates at a concentration of 156.25 µg/mL. Moreover, MIC of the curcumin nanoparticle for isolates was 625 µg/mL. Based on fraction inhibition concentration, synergy, and the additive effect were shown against %7.7, and %93.3 of MDRs, respectively. The sub-MIC concentration of the binary compound reduced biofilms and algD gene expression in P. aeruginosa isolates. The Biological function of HDF cell lines was desirable after the effect of the binary compound.

CONCLUSIONS: Regarding our results, this combination can be suggested as a promising agent in terms of biofilm inhibitory and antimicrobial properties.}, } @article {pmid37378390, year = {2023}, author = {Šmitran, A and Sladojević, Ž and Božić, L and Gajić, I and Marković, T and Kasagić, D and Subić, I and Katalina, G and Golić, B}, title = {Comparison of biofilm production and virulence genes distribution among human and canine isolates of Staphylococcus aureus.}, journal = {Iranian journal of veterinary research}, volume = {24}, number = {1}, pages = {74-80}, pmid = {37378390}, issn = {1728-1997}, abstract = {BACKGROUND: Staphylococcus aureus is an important human and animal pathogen that can cause a wide range of infections due to numerous virulence factors.

AIMS: The aim of this study was to compare biofilm formation ability with different virulence factors such as bacterial motility, genes encoding biofilm associated proteins, and Panton-Valentine leukocidin (PVL) among human and canine isolates of S. aureus.

METHODS: A total of 60 human (30 methicillin sensitive S. aureus (MSSA) and 30 methicillin resistant S. aureus (MRSA)) and 17 canine (all MSSA) isolates of S. aureus were tested for the capability of biofilm production, motility assay, and presence of genes encoding virulence factors: ica (encoding intercellular adhesion), bap (encoding biofilm-associated protein), fnbA (encoding fibronectin-binding protein A), cna (encoding collagen-binding protein), and pvl (encoding PVL).

RESULTS: Animal isolates of S. aureus performed better biofilm production than the human strains (P=0.042), as well as human MSSA compared to the MRSA isolates (P=0.013). Our results showed that cna, fnbA, and ica genes (67.5%, 66.2%, and 42.9%, respectively) were more prevalent than bap and pvl genes (0%, and 7.8%, respectively). The ica gene was significantly more prevalent in human isolates compared to animal isolates (n=31/60 vs. n=2/17, P=0.008), whereas the cna gene was more frequent in animal isolates than in human ones (n=15/17 vs. n=37/60, P=0.0201). Significant correlations were found between the biofilm formation of animal isolates, and the presence of fnbA (P=0.029) and ica genes (P=0.001).

CONCLUSION: This study showed a correlation between biofilm production and the presence of certain biofilm-related genes in animal isolates, as well as stronger biofilm production among MSSA human and animal isolates.}, } @article {pmid37376834, year = {2023}, author = {Kong, Q and Qi, M and Li, W and Shi, Y and Su, J and Xiao, S and Sun, J and Bai, X and Dong, B and Wang, L}, title = {A Novel Z-Scheme Heterostructured Bi2 S3 /Cu-TCPP Nanocomposite with Synergistically Enhanced Therapeutics against Bacterial Biofilm Infections in Periodontitis.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2302547}, doi = {10.1002/smll.202302547}, pmid = {37376834}, issn = {1613-6829}, support = {82170998//National Science Foundation of China/ ; 52250007//National Science Foundation of China/ ; 62205122//National Science Foundation of China/ ; 20220204128YY//Key Program of Natural Science Foundation of Jilin Province/ ; 20220402005GH//Key Program of Natural Science Foundation of Jilin Province/ ; 2022C044-1//Funding of Jilin Province Development and Reform Commission/ ; 2021C035-1//Funding of Jilin Province Development and Reform Commission/ ; JCSZ2021893-15//Science and Technology Project of Jilin Province Financial Department/ ; //Key Research and Development Program of Science/ ; 20220203145SF//Technology Development Project of Jilin Province/ ; 20210203087SF//Technology Development Project of Jilin Province/ ; 2022JC076//Health Department Research Projects of Jilin Province/ ; //Fundamental Research Funds for the Central Universities/ ; 2022YFSY0057//Sichuan Science and Technology Programs/ ; }, abstract = {Porphyrin-based antibacterial photodynamic therapy (aPDT) has found widespread applications in treating periodontitis. However, its clinical use is limited by poor energy absorption, resulting in limited reactive oxygen species (ROS) generation. To overcome this challenge, a novel Z-scheme heterostructured nanocomposite of Bi2 S3 /Cu-TCPP is developed. This nanocomposite exhibits highly efficient light absorption and effective electron-hole separation, thanks to the presence of heterostructures. The enhanced photocatalytic properties of the nanocomposite facilitate effective biofilm removal. Theoretical calculations confirm that the interface of the Bi2 S3 /Cu-TCPP nanocomposite readily adsorbs oxygen molecules and hydroxyl radicals, thereby improving ROS production rates. Additionally, the photothermal treatment (PTT) using Bi2 S3 nanoparticles promotes the release of Cu[2+] ions, enhancing the chemodynamic therapy (CDT) effect and facilitating the eradication of dense biofilms. Furthermore, the released Cu[2+] ions deplete glutathione in bacterial cells, weakening their antioxidant defense mechanisms. The synergistic effect of aPDT/PTT/CDT demonstrates potent antibacterial activity against periodontal pathogens, particularly in animal models of periodontitis, resulting in significant therapeutic effects, including inflammation alleviation and bone preservation. Therefore, this design of semiconductor-sensitized energy transfer represents an important advancement in improving aPDT efficacy and the treatment of periodontal inflammation.}, } @article {pmid37376175, year = {2023}, author = {Tanaka, CJ and Rodrigues, JA and Pingueiro, JMS and Macedo, TT and Feres, M and Shibli, JA and Bueno-Silva, B}, title = {Antibacterial Activity of a Bioactive Tooth-Coating Material Containing Surface Pre-Reacted Glass in a Complex Multispecies Subgingival Biofilm.}, journal = {Pharmaceutics}, volume = {15}, number = {6}, pages = {}, doi = {10.3390/pharmaceutics15061727}, pmid = {37376175}, issn = {1999-4923}, abstract = {Bioactive materials were developed with the ability to release fluoride and provide some antimicrobial potential, to be widely used in dentistry today. However, few scientific studies have evaluated the antimicrobial activity of bioactive surface pre-reacted glass (S-PRG) coatings (PRG Barrier Coat, Shofu, Kyoto, Japan) on periodontopathogenic biofilms. This study evaluated the antibacterial activity of S-PRG fillers on the microbial profile of multispecies subgingival biofilms. A Calgary Biofilm Device (CBD) was used to grow a 33-species biofilm related to periodontitis for 7 days. The S-PRG coating was applied on CBD pins from the test group and photo-activated (PRG Barrier Coat, Shofu), while the control group received no coating. Seven days after treatment, the total bacterial counts, metabolic activity, and microbial profile of the biofilms were observed using a colorimetric assay and DNA-DNA hybridization. Statistical analyses were applied; namely, the Mann-Whitney, Kruskal-Wallis, and Dunn's post hoc tests. The bacterial activity of the test group was reduced by 25.7% compared with that of the control group. A statistically significant reduction was observed for the counts of 15 species: A. naeslundii, A. odontolyticus, V. parvula, C. ochracea, C. sputigena, E. corrodens, C. gracilis, F. nucleatum polymorphum, F. nucleatum vincentii, F. periodonticum, P. intermedia, P. gingivalis, G. morbillorum, S. anginosus, and S. noxia (p ≤ 0.05). The bioactive coating containing S-PRG modified the composition of the subgingival biofilm in vitro, thereby decreasing colonization by pathogens.}, } @article {pmid37375527, year = {2023}, author = {Angelidis, AS and Grammenou, AS and Kotzamanidis, C and Giadinis, ND and Zdragas, AG and Sergelidis, D}, title = {Prevalence, Serotypes, Antimicrobial Resistance and Biofilm-Forming Ability of Listeria monocytogenes Isolated from Bulk-Tank Bovine Milk in Northern Greece.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, doi = {10.3390/pathogens12060837}, pmid = {37375527}, issn = {2076-0817}, abstract = {The prevalence of Listeria monocytogenes in bovine bulk-tank milk (BTM) in Greece has not been previously investigated. The aim of the study was to estimate the prevalence of L. monocytogenes in bovine BTM in Greece and to characterize the isolates in terms of carriage of genes encoding for pathogenic determinants, assess the isolates' biofilm-forming ability and determine their susceptibility against 12 antimicrobials. Samples (n = 138) of bovine BTM were obtained from farms located throughout Northern Greece and were analyzed qualitatively and quantitatively for L. monocytogenes. Five samples (3.6%) tested positive for L. monocytogenes. The pathogen's populations in these positive samples were below 5 CFU/mL. Most isolates belonged to the molecular serogroup "1/2a, 3a". All isolates carried the virulence genes inlA, inlC, inlJ, iap, plcA and hlyA, but actA was detected in only three isolates. The isolates displayed weak to moderate biofilm-forming ability and distinct antimicrobial resistance profiles. All isolates were characterized as multidrug resistant, with resistance to penicillin and clindamycin being a common feature. Considering that L. monocytogenes constitutes a serious public health threat, the key findings of the study, related to the carriage of virulence genes and multidrug resistance, highlight the importance of continued monitoring of the pathogen in farm animals.}, } @article {pmid37375494, year = {2023}, author = {Galgano, M and Mrenoshki, D and Pellegrini, F and Capozzi, L and Cordisco, M and Del Sambro, L and Trotta, A and Camero, M and Tempesta, M and Buonavoglia, D and Laricchiuta, P and Catella, C and Pratelli, A and Buonavoglia, A and Corrente, M}, title = {Antibacterial and Biofilm Production Inhibition Activity of Thymus vulgaris L. Essential Oil against Salmonella spp. Isolates from Reptiles.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, doi = {10.3390/pathogens12060804}, pmid = {37375494}, issn = {2076-0817}, abstract = {Salmonellosis is an infectious disease affecting both animals and humans. Antimicrobial resistant (AMR) and biofilm-producing Salmonella spp., frequently detected in reptiles (who can then act as asymptomatic carriers for warm-blooded animals), have developed resistance to biocides; this represents a warning for the emergence of biocide/antimicrobial cross-resistance. The aim of this study was to evaluate the efficacy of Thymus vulgaris L. essential oil (TEO) in inhibiting bacterial growth and biofilm production of Salmonella spp., which had been isolated from wild reptiles housed in a Zoo in Italy. The resistance profile against different classes of antibiotics showed that all the isolates were susceptible to the tested antibiotics, despite the presence of several AMR genes. All the isolates were also tested with aqueous solutions of TEO at different dilutions (5% to 0.039%). Interestingly, TEO proved effective both in inhibiting bacterial growth at low dilutions, with MIC and MBC values ranging between 0.078% and 0.312%, and in inhibiting biofilm production, with values ranging from 0.039% to 0.156%. TEO demonstrated effective bioactivity against the biofilm producer Salmonella spp., proving to be a valid disinfectant for the prevention of salmonellosis from reptiles, a possible source of infection for humans exposed to the reptiles' environment.}, } @article {pmid37375116, year = {2023}, author = {Sharma, S and Mohler, J and Mahajan, SD and Schwartz, SA and Bruggemann, L and Aalinkeel, R}, title = {Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061614}, pmid = {37375116}, issn = {2076-2607}, abstract = {Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.}, } @article {pmid37375105, year = {2023}, author = {Myintzaw, P and Pennone, V and McAuliffe, O and Begley, M and Callanan, M}, title = {Association of Virulence, Biofilm, and Antimicrobial Resistance Genes with Specific Clonal Complex Types of Listeria monocytogenes.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061603}, pmid = {37375105}, issn = {2076-2607}, support = {15F604, 2019R495//Department of Agriculture Food and the Marine/ ; }, abstract = {Precise classification of foodborne pathogen Listeria monocytogenes is a necessity in efficient foodborne disease surveillance, outbreak detection, and source tracking throughout the food chain. In this study, a total of 150 L. monocytogenes isolates from various food products, food processing environments, and clinical sources were investigated for variations in virulence, biofilm formation, and the presence of antimicrobial resistance genes based on their Whole-Genome Sequences. Clonal complex (CC) determination based on Multi-Locus Sequence Typing (MLST) revealed twenty-eight CC-types including eight isolates representing novel CC-types. The eight isolates comprising the novel CC-types share the majority of the known (cold and acid) stress tolerance genes and are all genetic lineage II, serogroup 1/2a-3a. Pan-genome-wide association analysis by Scoary using Fisher's exact test identified eleven genes specifically associated with clinical isolates. Screening for the presence of antimicrobial and virulence genes using the ABRicate tool uncovered variations in the presence of Listeria Pathogenicity Islands (LIPIs) and other known virulence genes. Specifically, the distributions of actA, ecbA, inlF, inlJ, lapB, LIPI-3, and vip genes across isolates were found to be significantly CC-dependent while the presence of ami, inlF, inlJ, and LIPI-3 was associated with clinical isolates specifically. In addition, Roary-derived phylogenetic grouping based on Antimicrobial-Resistant Genes (AMRs) revealed that the thiol transferase (FosX) gene was present in all lineage I isolates, and the presence of the lincomycin resistance ABC-F-type ribosomal protection protein (lmo0919_fam) was also genetic-lineage-dependent. More importantly, the genes found to be specific to CC-type were consistent when a validation analysis was performed with fully assembled, high-quality complete L. monocytogenes genome sequences (n = 247) extracted from the National Centre for Biotechnology Information (NCBI) microbial genomes database. This work highlights the usefulness of MLST-based CC typing using the Whole-Genome Sequence as a tool in classifying isolates.}, } @article {pmid37375095, year = {2023}, author = {Todorić, O and Pezo, L and Šarić, L and Kolarov, V and Varga, A and Čabarkapa, I and Kocić-Tanackov, S}, title = {Comparison of the Efficiency of Selected Disinfectants against Planktonic and Biofilm Populations of Escherichia coli and Staphylococcus aureus.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061593}, pmid = {37375095}, issn = {2076-2607}, support = {the Agreements on the Implementation and Financing of Research (nos. 451-03-47/2023-01/200222 and 451-03-47/2023-01/200051); grant number 142-451-3163/2022-02//Ministry of Science, Technological Development and Innovation of the Republic of Serbia; Provincial Secretariat for Higher Education and Scientific Research, Autonomous Province of Vojvodina, Republic of Serbia/ ; }, abstract = {The aim of this study is to compare the efficacy of selected food disinfectants on planktonic populations of Staphylococcus aureus and Escherichia coli and on the same microorganisms (MOs) incorporated in a biofilm. Two disinfectants were used for treatment: peracetic acid-based disinfectant (P) and benzalkonium chloride-based disinfectant (D). Testing of their efficacy on the selected MO populations was performed using a quantitative suspension test. The standard colony counting procedure was used to determine their efficacy on bacterial suspensions in tryptone soy agar (TSA). The germicidal effect (GE) of the disinfectants was determined based on the decimal reduction ratio. For both MOs, 100% GE was achieved at the lowest concentration (0.1%) and after the shortest exposure time (5 min). Biofilm production was confirmed with a crystal violet test on microtitre plates. Both E. coli and S. aureus showed strong biofilm production at 25 °C with E. coli showing significantly higher adherence capacity. Both disinfectants show a significantly weaker GE on 48 h biofilms compared to the GE observed after application of the same concentrations on planktonic cells of the same MOs. Complete destruction of the viable cells of the biofilms was observed after 5 min of exposure to the highest concentration tested (2%) for both disinfectants and MOs tested. The anti-quorum sensing activity (anti-QS) of disinfectants P and D was determined via a qualitative disc diffusion method applied to the biosensor bacterial strain Chromobacterium violaceum CV026. The results obtained indicate that the disinfectants studied have no anti-QS effect. The inhibition zones around the disc therefore only represent their antimicrobial effect.}, } @article {pmid37375035, year = {2023}, author = {Oknin, H and Kroupitski, Y and Shemesh, M and Blum, S}, title = {Upregulation of ica Operon Governs Biofilm Formation by a Coagulase-Negative Staphylococcus caprae.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061533}, pmid = {37375035}, issn = {2076-2607}, support = {845-0292-17//Israel Dairy Board/ ; }, abstract = {Staphylococcus caprae is a Gram-positive, coagulase-negative staphylococci (CoNS), which appears as commensal in the skin, as well as a prevalent mastitis pathogen of goats. Occasionally, it is also associated with infections in humans. Biofilm formation has been identified as a putative virulence factor in S. caprae. Biofilms are multicellular communities protected by a self-produced extracellular matrix (ECM), which facilitates the resistance of bacterial cells to antimicrobial treatments. The ECM is constructed by exopolysaccharides, including the major exopolysaccharide-polysaccharide intercellular adhesion (PIA), regulated by the ica operon in Staphylococcus species. The aim of this study was to characterize the expression of the ica operon in relation to biofilm formation in S. caprae. Results showed that within a few hours of growth, S. caprae could adhere to polystyrene surfaces, start to accumulate, and form biofilm. Peak biofilm biomass and maturation were reached after 48 h, followed by a reduction in biomass after 72 h. Confocal laser scanning microscopy showed the expression of matrix-associated proteins and polysaccharides at various time points. The expression dynamics of the ica operon were investigated using real-time reverse transcriptase PCR (RT)-qPCR, which showed elevated expression during the early stages of biofilm formation and subsequent downregulation throughout the biofilm aging process. In conclusion, our results show that the ica operon is essential in regulating biofilm formation in S. caprae, similar to other Staphylococcus species. Furthermore, the robustness of the observed biofilm phenotype could account for the successful intramammary colonization and may explain disease persistence caused by this pathogenic bacterium.}, } @article {pmid37374988, year = {2023}, author = {Sharipova, M and Rudakova, N and Mardanova, A and Evtugyn, V and Akosah, Y and Danilova, I and Suleimanova, A}, title = {Biofilm Formation by Mutant Strains of Bacilli under Different Stress Conditions.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061486}, pmid = {37374988}, issn = {2076-2607}, support = {22-16-00138//Russian Science Foundation/ ; }, abstract = {Bacillus subtilis is traditionally classified as a PGPR that colonizes plant roots through biofilm formation. The current study focused on investigating the influence of various factors on bacilli biofilm formation. In the course of the study, the levels of biofilm formation by the model strain B. subtilis WT 168 and on its basis created regulatory mutants, as well as strains of bacilli with deleted extracellular proteases under conditions of changes in temperature, pH, salt and oxidative stress and presence of divalent metals ions. B. subtilis 168 forms halotolerant and oxidative stress-resistant biofilms at a temperature range of 22 °C-45 °C and a pH range of 6-8.5. The presence of Ca[2+], Mn[2+] and Mg[2+] upsurges the biofilm development while an inhibition with Zn[2+]. Biofilm formation level was higher in protease-deficient strains. Relative to the wild-type strain, degU mutants showed a decrease in biofilm formation, abrB mutants formed biofilms more efficiently. spo0A mutants showed a plummeted film formation for the first 36 h, followed by a surge after. The effect of metal ions and NaCl on the mutant biofilms formation is described. Confocal microscopy indicated that B. subtilis mutants and protease-deficient strains differ in matrix structure. The highest content of amyloid-like proteins in mutant biofilms was registered for degU-mutants and protease-deficient strains.}, } @article {pmid37374916, year = {2023}, author = {Thomassen, GMB and Reiche, T and Hjørungnes, M and Mehli, L}, title = {High Disinfectant Tolerance in Pseudomonas spp. Biofilm Aids the Survival of Listeria monocytogenes.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061414}, pmid = {37374916}, issn = {2076-2607}, abstract = {Pseudomonas spp. are the most commonly found bacteria in food-processing environments due to properties such as a high growth rate at low temperatures, a high tolerance of antimicrobial agents, and biofilm formation. In this study, a set of Pseudomonas isolates originating from cleaned and disinfected surfaces in a salmon processing facility were screened for biofilm formation at 12 °C. A high variation in biofilm formation between the isolates was observed. Selected isolates, in both planktonic and biofilm states, were tested for resistance/tolerance to a commonly used disinfectant (peracetic acid-based) and antibiotic florfenicol. Most isolates showed a much higher tolerance in the biofilm state than in the planktonic state. In a multi-species biofilm experiment with five Pseudomonas strains with and without a Listeria monocytogenes strain, the Pseudomonas biofilm appeared to aid the survival of L. monocytogenes cells after disinfection, underscoring the importance of controlling the bacterial load in food-processing environments.}, } @article {pmid37374880, year = {2023}, author = {Milia, EP and Sardellitti, L and Eick, S}, title = {Antimicrobial Efficiency of Pistacia lentiscus L. Derivates against Oral Biofilm-Associated Diseases-A Narrative Review.}, journal = {Microorganisms}, volume = {11}, number = {6}, pages = {}, doi = {10.3390/microorganisms11061378}, pmid = {37374880}, issn = {2076-2607}, abstract = {Pistacia lentiscus L. (PlL) has been used for centuries in traditional medicine. The richness in antimicrobial biomolecules of Pll derivates can represent an alternative to chemically formulated agents used against oral infections. This review summarizes the knowledge on the antimicrobial activity of PlL essential oil (EO), extracts, and mastic resin against microorganisms being of relevance in oral biofilm-associated diseases. Results demonstrated that the potential of PlL polyphenol extracts has led to increasing scientific interest. In fact, the extracts are a significantly more effective agent than the other PlL derivates. The positive findings regarding the inhibition of periodontal pathogens and C. albicans, together with the antioxidant activity and the reduction of the inflammatory responses, suggest the use of the extracts in the prevention and/or reversal of intraoral dysbiosis. Toothpaste, mouthwashes, and local delivery devices could be effective in the clinical management of these oral diseases.}, } @article {pmid37374493, year = {2023}, author = {Nastulyavichus, A and Tolordava, E and Kudryashov, S and Khmelnitskii, R and Ionin, A}, title = {Laser-Induced Transferred Antibacterial Nanoparticles for Mixed-Species Bacteria Biofilm Inactivation.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {12}, pages = {}, doi = {10.3390/ma16124309}, pmid = {37374493}, issn = {1996-1944}, abstract = {In the present study, copper and silver nanoparticles with a concentration of 20 µg/cm[2] were synthesized using the method of laser-induced forward transfer (LIFT). The antibacterial activity of the nanoparticles was tested against bacterial biofilms that are common in nature, formed by several types of microorganisms (mixed-species bacteria biofilms): Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The Cu nanoparticles showed complete inhibition of the bacteria biofilms used. In the course of the work, a high level of antibacterial activity was demonstrated by nanoparticles. This activity manifested in the complete suppression of the daily biofilm, with the number of bacteria decreasing by 5-8 orders of magnitude from the initial concentration. To confirm antibacterial activity, and determine reductions in cell viability, the Live/Dead Bacterial Viability Kit was used. FTIR spectroscopy revealed that after Cu NP treatment, there was in a slight shift in the region, which corresponded to fatty acids, indicating a decrease in the relative motional freedom of molecules.}, } @article {pmid37374262, year = {2023}, author = {Codru, IR and Sava, M and Vintilă, BI and Bereanu, AS and Bîrluțiu, V}, title = {A Study on the Contributions of Sonication to the Identification of Bacteria Associated with Intubation Cannula Biofilm and the Risk of Ventilator-Associated Pneumonia.}, journal = {Medicina (Kaunas, Lithuania)}, volume = {59}, number = {6}, pages = {}, doi = {10.3390/medicina59061058}, pmid = {37374262}, issn = {1648-9144}, abstract = {Ventilator-associated pneumonia is one of the most severe complications of critically ill patients that need mechanical respiratory support, as it poses a significant risk of prolonging hospitalization, disability, and even death. This is why physicians worldwide target newer methods for prevention, early diagnosis, and early target treatment for this condition. There are few methods for a quick etiological diagnosis of pneumonia, especially point of care, and most are only readily available in some intensive care units. This is why a new, simple, and cheap method is needed for determining the bacteria that might be infectious in a particular patient. The manner in question is sonication. Method: In this prospective, observational, single-center study, endotracheal cannula specimens will be collected from at least 100 patients in our intensive care unit. This specimen will be submitted to a specific sonication protocol for bacteria to dislodge the biofilm inside the cannula. The resulting liquid will be seeded on growth media, and then a comparison will be made between the germs in the biofilm and the ones in the tracheal secretion of the patient. The primary purpose is to determine the bacteria before the appearance of a manifest infection.}, } @article {pmid37374013, year = {2023}, author = {Parker, DM and Koch, JA and Gish, CG and Brothers, KM and Li, W and Gilbertie, J and Rowe, SE and Conlon, BP and Byrapogu, VKC and Urish, KL}, title = {Hydrogen Peroxide, Povidone-Iodine and Chlorhexidine Fail to Eradicate Staphylococcus aureus Biofilm from Infected Implant Materials.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {6}, pages = {}, doi = {10.3390/life13061230}, pmid = {37374013}, issn = {2075-1729}, support = {NCATS KL2TR000146/TR/NCATS NIH HHS/United States ; NIAMS K08AR071494/AR/NIAMS NIH HHS/United States ; R03AR077602/AR/NIAMS NIH HHS/United States ; }, abstract = {Hydrogen peroxide, povidone-iodine, and chlorhexidine are antiseptics that are commonly added to irrigants to either prevent or treat infection. There are little clinical data available that demonstrate efficacy of adding antiseptics to irrigants in the treatment of periprosthetic joint infection after biofilm establishment. The objective of the study was to assess the bactericidal activity of the antiseptics on S. aureus planktonic and biofilm. For planktonic irrigation, S. aureus was exposed to different concentrations of antiseptics. S. aureus biofilm was developed by submerging a Kirschner wire into normalized bacteria and allowing it to grow for forty-eight hours. The Kirschner wire was then treated with irrigation solutions and plated for CFU analysis. Hydrogen peroxide, povidone-iodine, and chlorhexidine were bactericidal against planktonic bacteria with over a 3 log reduction (p < 0.0001). Unlike cefazolin, the antiseptics were not bactericidal (less than 3 log reduction) against biofilm bacteria but did have a statistical reduction in biofilm as compared to the initial time point (p < 0.0001). As compared to cefazolin treatment alone, the addition of hydrogen peroxide or povidone-iodine to cefazolin treatment only additionally reduced the biofilm burden by less than 1 log. The antiseptics demonstrated bactericidal properties with planktonic S. aureus; however, when used to irrigate S. aureus biofilms, these antiseptics were unable to decrease biofilm mass below a 3 log reduction, suggesting that S. aureus biofilm has a tolerance to antiseptics. This information should be considered when considering antibiotic tolerance in established S. aureus biofilm treatment.}, } @article {pmid37373560, year = {2023}, author = {Maliszewska, I and Zdubek, A}, title = {Correction: Maliszewska et al. On the Photo-Eradication of Methicillin-Resistant Staphylococcus aureus Biofilm Using Methylene Blue. Int. J. Mol. Sci. 2022, 24, 791.}, journal = {International journal of molecular sciences}, volume = {24}, number = {12}, pages = {}, doi = {10.3390/ijms241210221}, pmid = {37373560}, issn = {1422-0067}, abstract = {The authors wish to make the following corrections to this paper [...].}, } @article {pmid37373346, year = {2023}, author = {Contreras Martínez, OI and Angulo Ortíz, A and Santafé Patiño, G and Peñata-Taborda, A and Berrio Soto, R}, title = {Isoespintanol Antifungal Activity Involves Mitochondrial Dysfunction, Inhibition of Biofilm Formation, and Damage to Cell Wall Integrity in Candida tropicalis.}, journal = {International journal of molecular sciences}, volume = {24}, number = {12}, pages = {}, doi = {10.3390/ijms241210187}, pmid = {37373346}, issn = {1422-0067}, support = {FCB-02-19 project//University of Córdoba/ ; }, abstract = {The growing increase in infections caused by C. tropicalis, associated with its drug resistance and consequent high mortality, especially in immunosuppressed people, today generates a serious global public health problem. In the search for new potential drug candidates that can be used as treatments or adjuvants in the control of infections by these pathogenic yeasts, the objective of this research was to evaluate the action of isoespintanol (ISO) against the formation of fungal biofilms, the mitochondrial membrane potential (ΔΨm), and its effect on the integrity of the cell wall. We report the ability of ISO to inhibit the formation of biofilms by up to 89.35%, in all cases higher than the values expressed by amphotericin B (AFB). Flow cytometric experiments using rhodamine 123 (Rh123) showed the ability of ISO to cause mitochondrial dysfunction in these cells. Likewise, experiments using calcofluor white (CFW) and analyzed by flow cytometry showed the ability of ISO to affect the integrity of the cell wall by stimulating chitin synthesis; these changes in the integrity of the wall were also observed through transmission electron microscopy (TEM). These mechanisms are involved in the antifungal action of this monoterpene.}, } @article {pmid37373189, year = {2023}, author = {Pilarska, AA and Marzec-Grządziel, A and Paluch, E and Pilarski, K and Wolna-Maruwka, A and Kubiak, A and Kałuża, T and Kulupa, T}, title = {Biofilm Formation and Genetic Diversity of Microbial Communities in Anaerobic Batch Reactor with Polylactide (PLA) Addition.}, journal = {International journal of molecular sciences}, volume = {24}, number = {12}, pages = {}, doi = {10.3390/ijms241210042}, pmid = {37373189}, issn = {1422-0067}, support = {DEC-2019/03/ST8/01867//National Science Centre, Poland/ ; SUBZ.A130.23.070//Wroclaw Medical University/ ; }, abstract = {In this paper, an anaerobic digestion (AD) study was conducted on confectionery waste with granular polylactide (PLA) as a cell carrier. Digested sewage sludge (SS) served as the inoculum and buffering agent of systems. This article shows the results of the analyses of the key experimental properties of PLA, i.e., morphological characteristics of the microstructure, chemical composition and thermal stability of the biopolymer. The evaluation of quantitative and qualitative changes in the genetic diversity of bacterial communities, performed using the state-of-the-art next generation sequencing (NGS) technique, revealed that the material significantly enhanced bacterial proliferation; however, it does not change microbiome biodiversity, as also confirmed via statistical analysis. More intense microbial proliferation (compared to the control sample, without PLA and not digested, CW-control, CW-confectionery waste) may be indicative of the dual role of the biopolymer-support and medium. Actinobacteria (34.87%) were the most abundant cluster in the CW-control, while the most dominant cluster in digested samples was firmicutes: in the sample without the addition of the carrier (CW-dig.) it was 68.27%, and in the sample with the addition of the carrier (CW + PLA) it was only 26.45%, comparable to the control sample (CW-control)-19.45%. Interestingly, the number of proteobacteria decreased in the CW-dig. sample (17.47%), but increased in the CW + PLA sample (39.82%) compared to the CW-control sample (32.70%). The analysis of biofilm formation dynamics using the BioFlux microfluidic system shows a significantly faster growth of the biofilm surface area for the CW + PLA sample. This information was complemented by observations of the morphological characteristics of the microorganisms using fluorescence microscopy. The images of the CW + PLA sample showed carrier sections covered with microbial consortia.}, } @article {pmid37370336, year = {2023}, author = {Baruch, Y and Golberg, K and Sun, Q and Yew-Hoong Gin, K and Marks, RS and Kushmaro, A}, title = {3,3'-Diindolylmethane (DIM): A Potential Therapeutic Agent against Cariogenic Streptococcus mutans Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, doi = {10.3390/antibiotics12061017}, pmid = {37370336}, issn = {2079-6382}, support = {2019YFH0113, ING-000398//International Research and Development Program of Sichuan (2019YFH0113) , SMART innovation grant ING-000398/ ; }, abstract = {Indole, a metabolite of the amino acid tryptophan, has been proven to act as a signal molecule in bacteria, acting in different aspects of biofilm formation. The oral biofilm is a type of biofilm that has consequences for human health. It is a complex, three-dimensional structure that develops on the surface of teeth via the attachment of primary microbial colonizers. Many oral infections are caused by an imbalance occurring in the microorganisms naturally found in oral biofilms and are considered major public health concerns. In this study, we test the effect of a natural bis-indole, 3,3'-Diindolylmethane (DIM), in mitigating the pathogenicity of the oral biofilm inhabiting bacterium Streptococcus mutans, a bacterium that is considered to be a principal etiological agent in dental caries. Our study found that DIM was able to attenuate S. mutans biofilm formation by 92%. Additionally, treatment with DIM lowered extracellular polymeric substance (EPS) production and decreased its durability significantly under acidic conditions. Therefore, the anti-biofilm and anti-virulence properties of DIM against S. mutans bacteria in an "oral setting" provides evidence for its usefulness in reducing biofilm formation and potentially for caries attenuation.}, } @article {pmid37370327, year = {2023}, author = {Roy, PK and Kim, SH and Jeon, EB and Park, EH and Park, SY}, title = {Inhibition of Listeria monocytogenes Cocktail Culture Biofilms on Crab and Shrimp Coupons and the Expression of Biofilm-Related Genes.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, doi = {10.3390/antibiotics12061008}, pmid = {37370327}, issn = {2079-6382}, support = {2021R1I1A3A04037468//National Research Foundation of Korea/ ; }, abstract = {Listeria monocytogenes, a bacterium that is transmitted by tainted food, causes the infection listeriosis. In this study, quercetin was tested for its antibacterial properties and effectiveness as a food additive in preventing the growth of L. monocytogenes cocktail (ATCC19117, ATCC19113, and ATCC15313) biofilms on crabs and shrimps. Quercetin showed the least bactericidal activity and no discernible microbial growth at a minimum inhibitory concentration (MIC) of 250 µg/mL. The biofilm inhibition was performed at sub-MICs (1/2, 1/4, and 1/8 MIC). There was no quercetin added to the control group. Additionally, the present work examines the expression of various genes related to biofilm formation and quorum sensing (flaA, fbp, agrA, hlyA, and prfA). The levels of target genes were all significantly down-regulated. Quercetin (0-125 µg/mL) on the surfaces of the crab and shrimp was studied; its inhibitory effects were measured as log reductions at 0.39-2.31 log CFU/cm[2] and 0.42-2.36 log CFU/cm[2], respectively (p < 0.05). Quercetin reduced the formation of biofilms by disrupting cell-to-cell connections and causing cell lysis, which led to the deformation of the cells, evidenced by FE-SEM (field-emission scanning electron microscopy). These findings emphasize the significance of using natural food agents to target bacteria throughout the entire food production process.}, } @article {pmid37370305, year = {2023}, author = {Awadelkareem, AM and Siddiqui, AJ and Noumi, E and Ashraf, SA and Hadi, S and Snoussi, M and Badraoui, R and Bardakci, F and Ashraf, MS and Danciu, C and Patel, M and Adnan, M}, title = {Biosynthesized Silver Nanoparticles Derived from Probiotic Lactobacillus rhamnosus (AgNPs-LR) Targeting Biofilm Formation and Quorum Sensing-Mediated Virulence Factors.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, doi = {10.3390/antibiotics12060986}, pmid = {37370305}, issn = {2079-6382}, support = {RG-21093//University of Hail/ ; }, abstract = {In recent years, bacterial pathogens have developed resistance to antimicrobial agents that have created a global threat to human health and environment. As a novel approach to combating antimicrobial resistance (AMR), targeting bacteria's virulent traits that can be explained by quorum sensing (QS) is considered to be one of the most promising approaches. In the present study, biologically synthesized silver nanoparticles derived from Lactobacillus rhamnosus (AgNPs-LR) were tested against three Gram-negative bacteria to determine whether they inhibited the formation of biofilms and triggered the virulence factors controlled by QS. In C. violaceum and S. marcescens, a remarkable inhibition (>70%) of QS-mediated violacein and prodigiosin production was recorded, respectively. A dose-dependent decrease in virulence factors of P. aeruginosa (pyocyanin, pyoverdine, LasA protease, LasB elastase and rhamnolipid production) was also observed with AgNPs-LR. The biofilm development was reduced by 72.56%, 61.70%, and 64.66% at highest sub-MIC for C. violaceum, S. marcescens and P. aeruginosa, respectively. Observations on glass surfaces have shown remarkable reductions in biofilm formation, with less aggregation of bacteria and a reduced amount of extra polymeric materials being formed from the bacteria. Moreover, swimming motility and exopolysaccharides (EPS) was also found to reduce in the presence of AgNPs-LR. Therefore, these results clearly demonstrate that AgNPs-LR is highly effective in inhibiting the development of biofilms and the QS-mediated virulent traits of Gram-negative bacteria. In the future, AgNPs-LR may be used as an alternative to conventional antibiotics for the treatment of bacterial infections after careful evaluation in animal models, especially for the development of topical antimicrobial agents.}, } @article {pmid37368772, year = {2023}, author = {Vargová, M and Zigo, F and Výrostková, J and Farkašová, Z and Rehan, IF}, title = {Biofilm-Producing Ability of Staphylococcus aureus Obtained from Surfaces and Milk of Mastitic Cows.}, journal = {Veterinary sciences}, volume = {10}, number = {6}, pages = {}, doi = {10.3390/vetsci10060386}, pmid = {37368772}, issn = {2306-7381}, support = {1-0162-23//VEGA/ ; }, abstract = {This study was conducted to evaluate the incidence of mastitis in 153 dairy cows and to evaluate the kinetics of adhesion of isolates obtained from surfaces and milk in comparison with the reference strain (RS), CCM 4223. The surfaces of the floor, teat cup, and cow restraints were aseptically swabbed in three replicates (n = 27). Of the total number of infected cows (n = 43), 11 samples were found to be positive for Staphylococcus aureus, 12 samples tested positive for non-aureus staphylococci, 6 samples tested positive for Streptococcus spp., and 11 samples tested positive for other bacteria (Escherichia coli, Pseudomonas spp.) or a mixed infection. The most represented pathogen in milk (11/43) and on surfaces (14/27) was S. aureus. The kinetics of adhesion of the reference strain and isolates of S. aureus on stainless steel surfaces were determined after 3, 6, 9, 12, 24, and 48 h, and 3, 6, 9, 12, and 15 days of incubation. All strains reached counts higher than 5 Log10 CFU/cm[2] needed for biofilm formation, except RS (4.40 Log10 CFU/cm[2]). The isolates of S. aureus revealed a higher capability to form biofilm in comparison with RS during the first 3 h (p < 0.001). Thus, there is a significant difference between the occurrence of S. aureus on monitored surfaces-floor, teat cup, and cow restraints-and the frequency with which mastitis is caused by S. aureus (p < 0.05). This finding raises the possibility that if various surfaces are contaminated by S. aureus, it can result in the formation of biofilm, which is a significant virulence factor.}, } @article {pmid37368211, year = {2023}, author = {Fajardo, C and Sánchez-Fortún, S and Videira-Quintela, D and Martin, C and Nande, M and D Ors, A and Costa, G and Guillen, F and Montalvo, G and Martin, M}, title = {Biofilm formation on polyethylene microplastics and their role as transfer vector of emerging organic pollutants.}, journal = {Environmental science and pollution research international}, volume = {}, number = {}, pages = {}, pmid = {37368211}, issn = {1614-7499}, support = {CTM2017-82424-P//Ministerio de Ciencia e Innovación/ ; Project CCG20/CC-040//Universidad de Alcalá/ ; }, abstract = {Microplastic (MP)-colonizing microorganisms are important links for the potential impacts on environmental, health, and biochemical circulation in various ecosystems but are not yet well understood. In addition, biofilms serve as bioindicators for the evaluation of pollutant effects on ecosystems. This study describes the ability of three polyethylene-type microplastics, white (W-), blue (B-), and fluorescent blue (FB-) MPs, to support microbial colonization of Pseudomonas aeruginosa, the effect of mixed organic contaminants (OCs: amoxicillin, ibuprofen, sertraline, and simazine) on plastic-associated biofilms, and the role of biofilms as transfer vectors of such emerging pollutants. Our results showed that P. aeruginosa had a strong ability to produce biofilms on MPs, although the protein amount of biomass formed on FB-MP was 1.6- and 2.4-fold higher than that on B- and W-MP, respectively. When OCs were present in the culture medium, a decrease in cell viability was observed in the W-MP biofilm (65.0%), although a general impairing effect of OCs on biofilm formation was ruled out. Microbial colonization influenced the ability of MPs to accumulate OCs, which was higher for FB-MP. In particular, the sorption of amoxicillin was lower for all bacterial-colonized MPs than for the bare MPs. Moreover, we analysed oxidative stress production to assess the impact of MPs or MPs/OCs on biofilm development. The exposure of biofilms to OCs induced an adaptive stress response reflected in the upregulation of the katB gene and ROS production, particularly on B- and FB-MP. This study improves our understanding of MP biofilm formation, which modifies the ability of MPs to interact with some organic pollutants. However, such pollutants could hinder microbial colonization through oxidative stress production, and thus, considering the key role of biofilms in biogeochemical cycles or plastic degradation, the co-occurrence of MPs/OCs should be considered to assess the potential risks of MPs in the environment.}, } @article {pmid37367261, year = {2023}, author = {Seo, BY and Son, K and Son, YT and Dahal, RH and Kim, S and Kim, J and Hwang, J and Kwon, SM and Lee, JM and Lee, KB and Kim, JW}, title = {Influence of Dental Titanium Implants with Different Surface Treatments Using Femtosecond and Nanosecond Lasers on Biofilm Formation.}, journal = {Journal of functional biomaterials}, volume = {14}, number = {6}, pages = {}, doi = {10.3390/jfb14060297}, pmid = {37367261}, issn = {2079-4983}, support = {no. 2022R1C1C2007040//National Research Foundation of Korea (NRF) grant funded by the Korean government/ ; 20018114//Bio Industry Technology Development Program of the Korea Evaluation Institute of Industrial Technology (KEIT) funded by the Ministry of Trade, Industry and Energy/ ; }, abstract = {This study aimed to evaluate the impact of different surface treatments (machined; sandblasted, large grit, and acid-etched (SLA); hydrophilic; and hydrophobic) on dental titanium (Ti) implant surface morphology, roughness, and biofilm formation. Four groups of Ti disks were prepared using distinct surface treatments, including femtosecond and nanosecond lasers for hydrophilic and hydrophobic treatments. Surface morphology, wettability, and roughness were assessed. Biofilm formation was evaluated by counting the colonies of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Prevotella intermedia (Pi) at 48 and 72 h. Statistical analysis was conducted to compare the groups using the Kruskal-Wallis H test and the Wilcoxon signed-rank test (α = 0.05). The analysis revealed that the hydrophobic group had the highest surface contact angle and roughness (p < 0.05), whereas the machined group had significantly higher bacterial counts across all biofilms (p < 0.05). At 48 h, the lowest bacterial counts were observed in the SLA group for Aa and the SLA and hydrophobic groups for Pg and Pi. At 72 h, low bacterial counts were observed in the SLA, hydrophilic, and hydrophobic groups. The results indicate that various surface treatments affect implant surface properties, with the hydrophobic surface using femtosecond laser treatment exerting a particularly inhibitory effect on initial biofilm growth (Pg and Pi).}, } @article {pmid37363240, year = {2023}, author = {García, V and Lestón, L and Parga, A and García-Meniño, I and Fernández, J and Otero, A and Olsen, JE and Herrero-Fresno, A and Mora, A}, title = {Genomics, biofilm formation and infection of bladder epithelial cells in potentially uropathogenic Escherichia coli (UPEC) from animal sources and human urinary tract infections (UTIs) further support food-borne transmission.}, journal = {One health (Amsterdam, Netherlands)}, volume = {16}, number = {}, pages = {100558}, doi = {10.1016/j.onehlt.2023.100558}, pmid = {37363240}, issn = {2352-7714}, abstract = {Escherichia coli is the main cause of urinary tract infections (UTI). While genomic comparison of specific clones recovered from animals, and human extraintestinal infections show high identity, studies demonstrating the uropathogenicity are lacking. In this study, comparative genomics combined with bladder-cell and biofilm formation assays, were performed for 31 E. coli of different origins: 7 from meat (poultry, beef, and pork); 2 from avian-farm environment; 12 from human uncomplicated UTI, uUTI; and 10 from human complicated UTI, cUTI. These isolates were selected based on their genetic uropathogenic (UPEC) status and phylogenetic background. In silico analysis revealed similar virulence-gene profiles, with flagella, type 1 and curli fimbriae, outer-membrane proteins (agn43, ompT, iha), and iron-uptake (iutA, entA, and fyuA) associated-traits as the most prevalent (>65%). In bladder-cell assays, moderate to strong values of association (83%, 60%, 77.8%) and invasion (0%, 70%, 55.5%) were exhibited by uUTI, cUTI, and animal-derived isolates, respectively. Of interest, uUTI isolates exhibited a significantly lower invasive capacity than cUTI isolates (p < 0.05). All isolates but one produced measurable biofilm. Notably, 1 turkey meat isolate O11:H6-F-ST457, and 2 cUTI isolates of the pandemic lineages O83:H42-F-ST1485-CC648 and O25b:H4-B2-ST131, showed strong association, invasion and biofilm formation. These isolates showed common carriage of type 1 fimbriae and csg operons, toxins (hlyF, tsh), iron uptake systems (iutA, entA, iroN), colicins, protectins (cvaC, iss, kpsM, traT), ompT, and malX. In summary, the similar in vitro behaviour found here for certain E. coli clones of animal origin would further reinforce the role of food-producing animals as a potential source of UPEC. Bladder-cell infection assays, combined with genomics, might be an alternative to in vivo virulence models to assess uropathogenicity.}, } @article {pmid37362926, year = {2023}, author = {Li, Y and Sun, G and Xie, J and Xiao, S and Lin, C}, title = {Antimicrobial photodynamic therapy against oral biofilm: influencing factors, mechanisms, and combined actions with other strategies.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1192955}, doi = {10.3389/fmicb.2023.1192955}, pmid = {37362926}, issn = {1664-302X}, abstract = {Oral biofilms are a prominent cause of a wide variety of oral infectious diseases which are still considered as growing public health problems worldwide. Oral biofilms harbor specific virulence factors that would aggravate the infectious process and present resistance to some traditional therapies. Antimicrobial photodynamic therapy (aPDT) has been proposed as a potential approach to eliminate oral biofilms via in situ-generated reactive oxygen species. Although numerous types of research have investigated the effectiveness of aPDT, few review articles have listed the antimicrobial mechanisms of aPDT on oral biofilms and new methods to improve the efficiency of aPDT. The review aims to summarize the virulence factors of oral biofilms, the progress of aPDT in various oral biofilm elimination, the mechanism mediated by aPDT, and combinatorial approaches of aPDT with other traditional agents.}, } @article {pmid37362497, year = {2023}, author = {Kelly, JP and Bae, AS and Taunton, J and Jardaly, A and Harris, RM}, title = {Superficial Surgical Site Infections in Primary Total Joint Arthroplasty: A Retrospective Analysis of Topical Anti-Biofilm Therapy.}, journal = {Cureus}, volume = {15}, number = {5}, pages = {e39490}, doi = {10.7759/cureus.39490}, pmid = {37362497}, issn = {2168-8184}, abstract = {Introduction Surgical site infections (SSI) following orthopedic procedures can cause significant morbidity and mortality, particularly in total joint arthroplasty. Biofilm formation in surgical wounds has made it difficult to prevent and treat these infections. SURGX® Antimicrobial Wound Gel (Next Science, Jacksonville, Florida, USA) was developed to disrupt biofilm formation but has not been evaluated in prophylactic use in total joint arthroplasty to prevent superficial SSI. Methods A retrospective chart review was performed at a single institution comparing the rate of SSI in patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). SSI data were collected from patients with standard postoperative dressings (Group A: Control) and patients with SURGX® applied as part of a standardized dressing following THA/TKA (Group B: Study). Rates of SSI were compared. Results SURGX® was administered to 120 patients, including 91 TKAs and 29 THAs. The overall infection rate in this cohort was 2.5%. No superficial site infections developed. The control group constituted 566 patients, with 386 TKAs and 180 THAs. The infection rate was 1.24%, which included one superficial infection. Binary logistic regression did not show different odds of developing infections with the use of SURGX® (OR = 2.23, 95% CI: 0.54-9.13, p = 0.27). Conclusion In our small retrospective study, Next Science SURGX® Antimicrobial Wound Gel did not demonstrate a statistically significant difference in the rate of superficial SSI in total joint arthroplasty; however, Group B did not have any superficial SSI.}, } @article {pmid37360468, year = {2023}, author = {Kumar, L and Bisen, M and Harjai, K and Chhibber, S and Azizov, S and Lalhlenmawia, H and Kumar, D}, title = {Advances in Nanotechnology for Biofilm Inhibition.}, journal = {ACS omega}, volume = {8}, number = {24}, pages = {21391-21409}, doi = {10.1021/acsomega.3c02239}, pmid = {37360468}, issn = {2470-1343}, abstract = {Biofilm-associated infections have emerged as a significant public health challenge due to their persistent nature and increased resistance to conventional treatment methods. The indiscriminate usage of antibiotics has made us susceptible to a range of multidrug-resistant pathogens. These pathogens show reduced susceptibility to antibiotics and increased intracellular survival. However, current methods for treating biofilms, such as smart materials and targeted drug delivery systems, have not been found effective in preventing biofilm formation. To address this challenge, nanotechnology has provided innovative solutions for preventing and treating biofilm formation by clinically relevant pathogens. Recent advances in nanotechnological strategies, including metallic nanoparticles, functionalized metallic nanoparticles, dendrimers, polymeric nanoparticles, cyclodextrin-based delivery, solid lipid nanoparticles, polymer drug conjugates, and liposomes, may provide valuable technological solutions against infectious diseases. Therefore, it is imperative to conduct a comprehensive review to summarize the recent advancements and limitations of advanced nanotechnologies. The present Review encompasses a summary of infectious agents, the mechanisms that lead to biofilm formation, and the impact of pathogens on human health. In a nutshell, this Review offers a comprehensive survey of the advanced nanotechnological solutions for managing infections. A detailed presentation has been made as to how these strategies may improve biofilm control and prevent infections. The key objective of this Review is to summarize the mechanisms, applications, and prospects of advanced nanotechnologies to provide a better understanding of their impact on biofilm formation by clinically relevant pathogens.}, } @article {pmid37359001, year = {2023}, author = {Taha, M and Arnaud, T and Lightly, TJ and Peters, D and Wang, L and Chen, W and Cook, BWM and Theriault, SS and Abdelbary, H}, title = {Combining bacteriophage and vancomycin is efficacious against MRSA biofilm-like aggregates formed in synovial fluid.}, journal = {Frontiers in medicine}, volume = {10}, number = {}, pages = {1134912}, doi = {10.3389/fmed.2023.1134912}, pmid = {37359001}, issn = {2296-858X}, abstract = {BACKGROUND: Biofilm formation is a major clinical challenge contributing to treatment failure of periprosthetic joint infection (PJI). Lytic bacteriophages (phages) can target biofilm associated bacteria at localized sites of infection. The aim of this study is to investigate whether combination therapy of phage and vancomycin is capable of clearing Staphylococcus aureus biofilm-like aggregates formed in human synovial fluid.

METHODS: In this study, S. aureus BP043, a PJI clinical isolate was utilized. This strain is a methicillin-resistant S. aureus (MRSA) biofilm-former. Phage Remus, known to infect S. aureus, was selected for the treatment protocol. BP043 was grown as aggregates in human synovial fluid. The characterization of S. aureus aggregates was assessed for structure and size using scanning electron microscopy (SEM) and flow cytometry, respectively. Moreover, the formed aggregates were subsequently treated in vitro with: (a) phage Remus [∼10[8] plaque-forming units (PFU)/ml], (b) vancomycin (500 μg/ml), or (c) phage Remus (∼10[8] PFU/ml) followed by vancomycin (500 μg/ml), for 48 h. Bacterial survival was quantified by enumeration [colony-forming units (CFU)/ml]. The efficacy of phage and vancomycin against BP043 aggregates was assessed in vivo as individual treatments and in combination. The in vivo model utilized Galleria mellonella larvae which were infected with BP043 aggregates pre-formed in synovial fluid.

RESULTS: Scanning electron microscopy (SEM) images and flow cytometry data demonstrated the ability of human synovial fluid to promote formation of S. aureus aggregates. Treatment with Remus resulted in significant reduction in viable S. aureus residing within the synovial fluid aggregates compared to the aggregates that did not receive Remus (p < 0.0001). Remus was more efficient in eliminating viable bacteria within the aggregates compared to vancomycin (p < 0.0001). Combination treatment of Remus followed by vancomycin was more efficacious in reducing bacterial load compared to using either Remus or vancomycin alone (p = 0.0023, p < 0.0001, respectively). When tested in vivo, this combination treatment also resulted in the highest survival rate (37%) 96 h post-treatment, compared to untreated larvae (3%; p < 0.0001).

CONCLUSION: We demonstrate that combining phage Remus and vancomycin led to synergistic interaction against MRSA biofilm-like aggregates in vitro and in vivo.}, } @article {pmid37358668, year = {2023}, author = {Fang, F and Xu, H and Chai, B and Li, D and Nie, L and Wen, Z and Yu, Z and Zheng, J and Zhang, H}, title = {Neobavaisoflavone Inhibits Biofilm Formation and α-Toxin Activity of Staphylococcus aureus.}, journal = {Current microbiology}, volume = {80}, number = {8}, pages = {258}, pmid = {37358668}, issn = {1432-0991}, support = {82172283//National Natural Science Foundation of China/ ; }, abstract = {Neobavaisoflavone had antimicrobial activities against Gram-positive multidrug-resistant (MDR) bacteria, but the effect of neobavaisoflavone on the virulence and biofilm formation of S. aureus has not been explored. The present study aimed to investigate the possible inhibitory effect of neobavaisoflavone on the biofilm formation and α-toxin activity of S. aureus. Neobavaisoflavone presented strong inhibitory effect on the biofilm formation and α-toxin activity of both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains at 25 µM, but did not affect the growth of S. aureus planktonic cells. Genetic mutations were identified in four coding genes, including cell wall metabolism sensor histidine kinase walK, RNA polymerase sigma factor rpoD, tetR family transcriptional regulator, and a hypothetical protein. The mutation of WalK (K570E) protein was identified and verified in all the neobavaisoflavone-induced mutant S. aureus isolates. The ASN501, LYS504, ILE544 and GLY565 of WalK protein act as hydrogen acceptors to form four hydrogen bonds with neobavaisoflavone by molecular docking analysis, and TRY505 of WalK protein contact with neobavaisoflavone to form a pi-H bond. In conclusion, neobavaisoflavone had excellent inhibitory effect on the biofilm formation and α-toxin activity of S. aureus. The WalK protein might be a potential target of neobavaisoflavone against S. aureus.}, } @article {pmid37358420, year = {2023}, author = {Ratheesh, NK and Zdimal, AM and Calderon, CA and Shrivastava, A}, title = {Bacterial Swarm-Mediated Phage Transportation Disrupts a Biofilm Inherently Protected from Phage Penetration.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0093723}, doi = {10.1128/spectrum.00937-23}, pmid = {37358420}, issn = {2165-0497}, abstract = {Physical forces that arise due to bacterial motility and growth play a significant role in shaping the biogeography of the human oral microbiota. Bacteria of the genus Capnocytophaga are abundant in the human oral microbiota and yet very little is known about their physiology. The human oral isolate Capnocytophaga gingivalis exhibits robust gilding motility that is driven by the rotary type 9 secretion system (T9SS), and cells of C. gingivalis transport nonmotile oral microbes as cargo. Phages, i.e., viruses that infect bacteria, are found in abundance within the microbiota. By tracking fluorescently labeled lambda phages that do not infect C. gingivalis, we report active phage transportation by C. gingivalis swarms. Lambda phage-carrying C. gingivalis swarms were propagated near an Escherichia coli colony. The rate of disruption of the E. coli colony increased 10 times compared with a control where phages simply diffused to the E. coli colony. This finding suggests a mechanism where fluid flows produced by motile bacteria increase the rate of transport of phages to their host bacterium. Additionally, C. gingivalis swarms formed tunnel-like structures within a curli fiber-containing E. coli biofilm that increased the efficiency of phage penetration. Our data suggest that invasion by a C. gingivalis swarm changes the spatial structure of the prey biofilm and further increases the penetration of phages. IMPORTANCE Dysbiosis of the human oral microbiota is associated with several diseases, but the factors that shape the biogeography of the oral microbiota are mostly opaque. Biofilms that form in the human supragingival and subgingival regions have a diverse microbial community where some microbes form well-defined polymicrobial structures. C. gingivalis, a bacterium abundant in human gingival regions, has robust gliding motility that is powered by the type 9 secretion system. We demonstrate that swarms of C. gingivalis can transport phages through a complex biofilm which increases the death rate of the prey biofilm. These findings suggest that C. gingivalis could be used as a vehicle for the transportation of antimicrobials and that active phage transportation could shape the spatial structure of a microbial community.}, } @article {pmid37362817, year = {2023}, author = {Meesilp, N and Mesil, N}, title = {Correction to: Effect of microbial sanitizers for reducing biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa on stainless steel by cultivation with UHT milk.}, journal = {Food science and biotechnology}, volume = {32}, number = {9}, pages = {1297}, doi = {10.1007/s10068-019-00721-6}, pmid = {37362817}, issn = {2092-6456}, abstract = {[This corrects the article DOI: 10.1007/s10068-018-0448-4.].}, } @article {pmid37357232, year = {2023}, author = {Cagnola, GN and Cabrera, JN and Negri, RM and D'Accorso, NB and Lizarraga, L and Pettinari, MJ}, title = {Biofilm Formation of Two Different Marine Bacteria on Modified PDMS Surfaces is Affected by Surface Roughness and Topography.}, journal = {Current microbiology}, volume = {80}, number = {8}, pages = {256}, pmid = {37357232}, issn = {1432-0991}, support = {PR4631//YTEC-CONICET/ ; 20020190100297BA//Secretaria de Ciencia y Tecnica, Universidad de Buenos Aires/ ; 20020170100433BA//Secretaria de Ciencia y Tecnica, Universidad de Buenos Aires/ ; 20020130100021BA//Secretaria de Ciencia y Tecnica, Universidad de Buenos Aires/ ; 11220200100993CO//Consejo Nacional de Investigaciones Científicas y Técnicas/ ; }, abstract = {Different strategies were tested to reduce biofilm formation of the model marine bacteria Cobetia marina and Marinobacter hydrocarbonoclasticus on cross-linked polydimethylsiloxane (PDMS) coated aluminum and cellulose acetate surfaces modified by addition of multi-walled carbon nanotubes (MWCNT) or exposure of the surfaces to bromine vapors in the presence and absence of UV irradiation. The three surface modifications explored led to important reductions in biofilm formation for the two marine bacteria, up to 30% in the case of exposure to Br2(g). Biofouling reduction could be correlated to surface properties in all cases through the introduction of a quantitative theoretical model based on an effective roughness parameter, Raeff, that accounted for the different morphological changes observed. The model considers the possibility of bacterial inclusion into large surface wells, as observed by AFM in the case of Br2(g) + UV light treatment. In addition, a linear relationship was observed between biofouling reduction and the Raeff effective roughness parameter.}, } @article {pmid37356913, year = {2023}, author = {Rajput, A and Bhamare, KT and Thakur, A and Kumar, M}, title = {Anti-Biofilm: Machine Learning Assisted Prediction of IC50 Activity of Chemicals Against Biofilms of Microbes Causing Antimicrobial Resistance and Implications in Drug Repurposing.}, journal = {Journal of molecular biology}, volume = {435}, number = {14}, pages = {168115}, doi = {10.1016/j.jmb.2023.168115}, pmid = {37356913}, issn = {1089-8638}, abstract = {Biofilms are one of the leading causes of antibiotic resistance. It acts as a physical barrier against the human immune system and drugs. The use of anti-biofilm agents helps in tackling the menace of antibiotic resistance. The identification of efficient anti-biofilm chemicals remains a challenge. Therefore, in this study, we developed 'anti-Biofilm', a machine learning technique (MLT) based predictive algorithm for identifying and analyzing the biofilm inhibition of small molecules. The algorithm is developed using experimentally validated anti-biofilm compounds with half maximal inhibitory concentration (IC50) values extracted from aBiofilm resource. Out of the five MLTs, the Support Vector Machine performed best with Pearson's correlation coefficient of 0.75 on the training/testing data set. The robustness of the developed model was further checked using an independent validation dataset. While analyzing the chemical diversity of the anti-biofilm compounds, we observed that they occupy diverse chemical spaces with parent molecules like furanone, urea, phenolic acids, quinolines, and many more. Use of diverse chemicals as input further signifies the robustness of our predictive models. The three best-performing machine learning models were implemented as a user-friendly 'anti-Biofilm' web server (https://bioinfo.imtech.res.in/manojk/antibiofilm/) with different other modules which make 'anti-Biofilm' a comprehensive platform. Therefore, we hope that our initiative will be helpful for the scientific community engaged in identifying effective anti-biofilm agents to target the problem of antimicrobial resistance.}, } @article {pmid37355959, year = {2023}, author = {Kuzma, J and Zavala-Meneses, SG and Skultety, L and Chmelar, D and Ficík, J and Palcová, L}, title = {Antibiotic resistance and biofilm-forming ability of α-toxin-positive Clostridium septicum isolates worsen patient prognosis.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13338}, pmid = {37355959}, issn = {1600-0463}, support = {//Faculty of Medicine Ostrava, University of Ostrava/ ; APVV 19-0519//Slovak Research and Development Agency/ ; }, abstract = {A total of, 78 Clostridium septicum (CLSE) isolates were screened for genes encoding: α-toxin, flagellin, and resistance to vancomycin (VANg). The isolates were also tested for their ability to form biofilm and their antibiotic susceptibility. All isolates were positive for α-toxin and flagellin genes. However, only 19 isolates (24.3%) showed prevalence for VANg. We observed the strongest capacity to form a biofilm (100%) in isolates from patients with oncologic or septic and febrile diagnoses. This percentage was also very high in patients with colitis and gastrointestinal hemorrhage (72.7%). No less than 43 isolates showed antibiotic resistance, and 21 were multidrug-resistant (MDR). Interestingly, our studies showed a correlation between antibiotic resistance and biofilm formation. A statistically significant difference was observed between biofilm-forming MDR isolates and those with low/no biofilm-forming ability. However, the most impressive observation was the correlation with mortality rate. While the overall mortality rate for CLSE infections was 16.7% (13/78), the mortality rate for patients infected with MDR isolates forming biofilm moderately or strongly reached 38.1% (8/21). This number increased even further when only infections with the biofilm-forming VANg-positive isolates were considered (61.5%; 8/13). Therefore, the ability of a VANg-positive CLSE isolate to form a biofilm has been suggested as a biomarker of poor prognosis.}, } @article {pmid37354952, year = {2023}, author = {Alagha, HZ and Gülsoy, M}, title = {Inactivation of planktonic cells and inhibitory effect on post-treatment biofilm formation of methicillin-resistant Staphylococcus aureus by photodynamic treatment with IR780 iodide loaded mesoporous silica nanoparticles and near infrared light.}, journal = {Journal of microbiological methods}, volume = {}, number = {}, pages = {106773}, doi = {10.1016/j.mimet.2023.106773}, pmid = {37354952}, issn = {1872-8359}, abstract = {The rapid spread of antimicrobial resistance is one of the biggest threats to global health. In the search for new treatment approaches that can eradicate pathogens without inducing drug-resistant strains, photodynamic therapy stands as a promising one. The aim of this study was to investigate the antimicrobial photodynamic potential of mesoporous silica nanoparticles (MSN) loaded with IR780 iodide on one of the most common multidrug-resistant bacteria both in hospitals and in the community, which is methicillin-resistant Staphylococcus aureus (MRSA). Mesoporous silica nanoparticles loaded with IR780 iodide were synthesized, their photodynamic and photothermal properties were examined, and their antimicrobial photodynamic potential against one methicillin-susceptible Staphylococcus aureus (MSSA), and one MRSA strain was investigated. Irradiation was achieved via a 785 nm diode laser (500 mW/cm[2], 5 min). Viable bacterial cells were counted by serial dilution method. The post-treatment biofilm recurring ability of MRSA was assessed 24 h post-PDT treatment using Crystal Violet assay. Scanning Electron Microscopy (SEM) of post-treatment biofilms was acquired. Data were analyzed by ANOVA followed by Tukey's test (p ≤ 0.05). Results revealed that mesoporous silica nanoparticles loaded with IR780 iodide-mediated photodynamic therapy were effective in killing both tested strains. The antimicrobial effect was stronger on MRSA, in which 3.54 logs of photokilling was observed. The killing was mainly due to the photochemical action of the nanoparticles. Post-treatment biofilm recurring ability of MRSA was much less in the treated group than that of the control group (50% inhibition), as confirmed by both optical density (OD = 570 nm) measurement and Scanning Electron Microscope (SEM) imaging.}, } @article {pmid37354591, year = {2023}, author = {Vlasopoulos, D and Mendrinou, P and Oustadakis, P and Kousi, P and Stergiou, A and Karamoutsos, SD and Hatzikioseyian, A and Tsakiridis, PE and Remoundaki, E and Agatzini-Leonardou, S}, title = {Hydrometallurgical recovery of silver and gold from waste printed circuit boards and treatment of the wastewater in a biofilm reactor: An integrated pilot application.}, journal = {Journal of environmental management}, volume = {344}, number = {}, pages = {118334}, doi = {10.1016/j.jenvman.2023.118334}, pmid = {37354591}, issn = {1095-8630}, abstract = {A hydrometallurgical process for the recovery of gold and silver from waste printed circuit boards (PCBs) was experimentally verified and tested at pilot scale. The process comprises four sequential leaching stages; the first two based on HCl, correspond to base metals (e.g. Sn, Cu) removal, while the third is based on HNO3 for Ag leaching and the final on aqua regia for Au leaching. After base metals leaching, the solid residue, enriched in silver and gold about 5 times, contained silver almost quantitively as insoluble AgCl and significant losses (Ag loss <8%) were avoided. The necessary reduction of Ag in the solid phase was achieved with a solution of 0.5 M N2H4 and 3 M NaOH, at 80 °C and S/L ratio 10%. Leaching of silver by 4 M HNO3 was followed by its recovery from nitrate solution by 0.08 Μ N2H4 at ambient temperature with an efficiency of 83%. Gold was leached by aqua regia and quantitively recovered by 0.13 M N2H4 at ambient temperature. Wastewater resulting from the process, rich in nitrate (5 g/L) and chloride (50 g/L), was treated by an effective and novel biological denitrification system tolerating metals at ppm level, to comply with zero nitrate and residual metals discharge guidelines. The overall process requires low reagents and energy input and has zero discharge for liquid effluents. The scheme is appropriate to be applied at local small to medium industrial units, complying with decentralized circular economy principles for metal recovery from electronic waste.}, } @article {pmid37349512, year = {2023}, author = {Lopez-Fernandez, M and Westmeijer, G and Turner, S and Broman, E and Ståhle, M and Bertilsson, S and Dopson, M}, title = {Thiobacillus as a key player for biofilm formation in oligotrophic groundwaters of the Fennoscandian Shield.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {41}, pmid = {37349512}, issn = {2055-5008}, abstract = {Biofilm formation is a common adaptation for microbes in energy-limited conditions such as those prevalent in the vast deep terrestrial biosphere. However, due to the low biomass and the inaccessible nature of subsurface groundwaters, the microbial populations and genes involved in its formation are understudied. Here, a flow-cell system was designed to investigate biofilm formation under in situ conditions in two groundwaters of contrasting age and geochemistry at the Äspö Hard Rock Laboratory, Sweden. Metatranscriptomes showed Thiobacillus, Sideroxydans, and Desulforegula to be abundant and together accounted for 31% of the transcripts in the biofilm communities. Differential expression analysis highlighted Thiobacillus to have a principal role in biofilm formation in these oligotrophic groundwaters by being involved in relevant processes such as the formation of extracellular matrix, quorum sensing, and cell motility. The findings revealed an active biofilm community with sulfur cycling as a prominent mode of energy conservation in the deep biosphere.}, } @article {pmid37348563, year = {2023}, author = {Huang, Z and Liu, S and Wang, Y and Yao, Z and Feng, L and Lin, Y and Ye, J and Zhou, T and Wang, Z}, title = {Comparison of prevalence, resistance, biofilm, and virulence between carbapenem nonsusceptible and susceptible Enterobacter cloacae complex in clusters.}, journal = {The Journal of hospital infection}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jhin.2023.06.017}, pmid = {37348563}, issn = {1532-2939}, abstract = {OBJECTIVES: This study aimed to explore the differences of prevalence, resistance, biofilm, and virulence between carbapenem nonsusceptible and susceptible Enterobacter cloacae complex (ECC) in different clusters.

METHODS: Ninety-one carbapenem nonsusceptible isolates and an equal number of susceptible isolates as well as their clinical information were collected from a university teaching hospital in China. The strains were divided into different clusters according to the analysis based on hsp60. Agar dilution method was used to determine the MICs of common antibiotics. Crystal violet assay was used to measure biofilm-forming ability. Galleria mellonella infection model and PCR of virulence genes were used to evaluate the virulence.

RESULTS: The isolates were divided into 12 clusters based on the hsp60 analysis. Cluster VIII accounted for a predominant and higher proportion of carbapenem nonsusceptible isolates than the other clusters. The same clusters exhibited different resistance rates in carbapenem nonsusceptible and susceptible isolates. Moreover, carbapenem nonsusceptible isolates carried fewer virulence genes than susceptible isolates, and cluster II in carbapenem nonsusceptible isolates didn't carry the detected virulence genes. The virulence of clusters I, III, VIII, and IX was significantly different between the nonsusceptible and susceptible isolates, as evaluated using the Galleria mellonella infection model. Cluster VIII accounted for a predominant and higher proportion as well as higher resistance, biofilm formation ability, and pathogenicity in carbapenem nonsusceptible isolates than the other clusters.

CONCLUSIONS: This finding indicated the necessity to identify subgroups of ECC and provide better advice and guidance for the use of carbapenem.}, } @article {pmid37348423, year = {2023}, author = {Mortensen, AT and Goonesekera, EM and Dechesne, A and Elad, T and Tang, K and Andersen, HR and Smets, BF and Valverde-Pérez, B}, title = {Methanotrophic oxidation of organic micropollutants and nitrogen upcycling in a hybrid membrane biofilm reactor (hMBfR) for simultaneous O2 and CH4 supply.}, journal = {Water research}, volume = {242}, number = {}, pages = {120104}, doi = {10.1016/j.watres.2023.120104}, pmid = {37348423}, issn = {1879-2448}, abstract = {Pharmaceuticals and other organic micropollutants (OMPs) present in wastewater effluents are of growing concern, as they threaten environmental and human health. Conventional biological treatments lead to limited removal of OMPs. Methanotrophic bacteria can degrade a variety of OMPs. By employing a novel bubble-free hybrid membrane biofilm bioreactor (hMBfR), we grew methanotrophic bacteria at three CH4 loading rates. Biomass productivity and CH4 loading showed a linear correlation, with a maximum productivity of 372 mg-VSS·L[-1]·d[-1], with corresponding biomass concentration of 1117.6 ± 56.4 mg-VSS·L[-1]. Furthermore, the biodegradation of sulfamethoxazole and 1H-benzotriazole positively correlated with CH4 oxidation rates, with highest biodegradation kinetic constants of 3.58 L·g[-1]·d[-1] and 5.42 L·g[-1]·d[-1], respectively. Additionally, the hMBfR recovered nutrients as microbial proteins, with an average content 39% DW. The biofilm community was dominated by Methylomonas, while the bulk was dominated by aerobic heterotrophic bacteria. The hMBfR removed OMPs, allowing for safer water reuse while valorising CH4 and nutrients.}, } @article {pmid37348303, year = {2023}, author = {Rezaee, A and Ahmady-Asbchin, S}, title = {Removal of toxic metal Cd (II) by Serratia bozhouensis CdIW2 using in moving bed biofilm reactor (MBBR).}, journal = {Journal of environmental management}, volume = {344}, number = {}, pages = {118361}, doi = {10.1016/j.jenvman.2023.118361}, pmid = {37348303}, issn = {1095-8630}, abstract = {The use of bioreactor technology to treat industrial wastewater containing heavy metals has created new perspectives. Cadmium metal is one of the toxic heavy metals that have harmful effects on human health and the environment. This research work presents a comprehensive approach for aqueous cadmium removal through biosorption in a moving bed biofilm reactor (MBBR). The bacterium resistant to Cd(II) (350 mg/L) CdIW2 was selected among 8 cadmium tolerant bacteria isolated from the industrial wastewater of the metal industry. 16S rRNA gene and phenotypic analysis showed that the bacterium CdIW2 is similar to Serratia bozhouensis. The highest biosorption capacity of 65.79 mg/g was acquired in optimal conditions (30 min, pH = 6, 0.5 g/L, and 35 °C). The biosorption of the CdIW2 strain was consistent with the Langmuir isotherm and the pseudo-second order kinetic and showed the process's spontaneous thermodynamic and endothermic results. The removal rate 91.74% of MBBR in batch mode was obtained in 72 h and 10 mg/L of Cd(II). Furthermore, continuous mode bioreactor analysis has shown high efficiency at intel loading rates of 6-36 mg/L. day for cadmium removal. The second order kinetic (Grau) was chosen as the suitable model for modeling the MBBR process. Although several studies have evaluated the removal of various types of heavy metals, none of the studies involved the use of a metal-resistant strain in an MBBR bioreactor.}, } @article {pmid37346997, year = {2023}, author = {Zheng, T and Jing, M and Gong, T and Yan, J and Wang, X and Xu, M and Zhou, X and Zeng, J and Li, Y}, title = {Regulatory mechanisms of exopolysaccharide synthesis and biofilm formation in Streptococcus mutans.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2225257}, pmid = {37346997}, issn = {2000-2297}, abstract = {BACKGROUND: Dental caries is a chronic, multifactorial and biofilm-mediated oral bacterial infection affecting almost every age group and every geographical region. Streptococcus mutans is considered an important pathogen responsible for the initiation and development of dental caries. It produces exopolysaccharides in situ to promote the colonization of cariogenic bacteria and coordinate dental biofilm development.

OBJECTIVE: The understanding of the regulatory mechanism of S. mutans biofilm formation can provide a theoretical basis for the prevention and treatment of caries.

DESIGN: At present, an increasing number of studies have identified many regulatory systems in S. mutans that regulate biofilm formation, including second messengers (e.g. c-di-AMP, Ap4A), transcription factors (e.g. EpsR, RcrR, StsR, AhrC, FruR), two-component systems (e.g. CovR, VicR), small RNA (including sRNA0426, srn92532, and srn133489), acetylation modifications (e.g. ActG), CRISPR-associated proteins (e.g. Cas3), PTS systems (e.g. EIIAB), quorum-sensing signaling system (e.g. LuxS), enzymes (including Dex, YidC, CopZ, EzrA, lmrB, SprV, RecA, PdxR, MurI) and small-molecule metabolites.

RESULTS: This review summarizes the recent progress in the molecular regulatory mechanisms of exopolysaccharides synthesis and biofilm formation in S. mutans.}, } @article {pmid37346320, year = {2023}, author = {Hoogenkamp, MA and Mazurel, D and Deutekom-Mulder, E and de Soet, JJ}, title = {The consistent application of hydrogen peroxide controls biofilm growth and removes Vermamoeba vermiformis from multi-kingdom in-vitro dental unit water biofilms.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100132}, pmid = {37346320}, issn = {2590-2075}, abstract = {The water systems inside a dental unit are known to be contaminated with a multi-kingdom biofilm encompassing bacteria, fungi, viruses and protozoa. Aerosolization of these micro-organisms can potentially create a health hazard for both dental staff and the patient. Very little is known on the efficacy of dental unit disinfection products against amoeba. In this study we have examined the effect of four different treatment regimens, with the hydrogen peroxide (H2O2) containing product Oxygenal, on an in-vitro multi-kingdom dental unit water system (DUWS) biofilm. The treatment efficacy was assessed in time using heterotrophic plate counts, the bacterial 16S rDNA, fungal 18S rDNA gene load and the number of genomic units for Legionella spp. the amoeba Vermamoeba vermiformis. The results indicated that a daily treatment of the DUWS with a low dose H2O2 (0.02% for 5 h), combined with a weekly shock dose (0.25% H2O2, 30 min) is necessary to reduce the heterotrophic plate count of a severely contaminated DUWS (>10[6] CFU.mL[-1]) to below 100 CFU.mL[-1]. A daily treatment with a low dose hydrogen peroxide alone, is sufficient for the statistically significant reduction of the total amount of bacterial 16S rDNA gene, Legionella spp. and Vermamoeba vermiformis load (p < 0.005). Also shown is that even though hydrogen peroxide does not kill the trophozoite nor the cysts of V. vermiformis, it does however result in the detachment of the trophozoite form of this amoeba from the DUWS biofilm and hereby ultimately removing the amoeba from the system.}, } @article {pmid37344657, year = {2023}, author = {Borges, KA and Furian, TQ and de Brito, BG and de Brito, KCT and da Rocha, DT and Salle, CTP and Moraes, HLS and do Nascimento, VP}, title = {Characterization of avian pathogenic Escherichia coli isolates based on biofilm formation, ESBL production, virulence-associated genes, and phylogenetic groups.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {}, number = {}, pages = {}, pmid = {37344657}, issn = {1678-4405}, abstract = {Escherichia coli is a part of both animal and human commensal microbiota. Avian pathogenic E. coli (APEC) is responsible for colibacillosis in poultry, an economically important disease. However, the close similarities among APEC isolates make it difficult to differentiate between pathogenic and commensal bacteria. The aim of this study was to determine phenotypic and molecular characteristics of APEC isolates and to compare them with their in vivo pathogenicity indices. A total of 198 APEC isolates were evaluated for their biofilm-producing ability and extended-spectrum β-lactamase (ESBL) production phenotypes. In addition, 36 virulence-associated genes were detected, and the isolates were classified into seven phylogenetic groups using polymerase chain reaction. The sources of the isolates were not associated with biofilms, ESBL, genes, or phylogroups. Biofilm and ESBL production were not associated with pathogenicity. Group B2 had the highest pathogenicity index. Groups B2 and E were positively associated with high-pathogenicity isolates and negatively associated with low-pathogenicity isolates. In contrast, groups A and C were positively associated with apathogenic isolates, and group B1 was positively associated with low-pathogenicity isolates. Some virulence-associated genes showed positive or negative associations with specific phylogenetic groups. None of the individual techniques produced results that correlated with the in vivo pathogenicity index. However, the combination of two techniques, namely, detection of virulence-associated genes and the phylogenetic groups, could help the classification of the isolates as pathogenic or commensal.}, } @article {pmid37343800, year = {2023}, author = {Jaiswal, VK and Sonwani, RK and Singh, RS}, title = {Construction and performance assessment of Recirculating packed bed biofilm reactor (RPBBR) for effective biodegradation of p-cresol from wastewater.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {129372}, doi = {10.1016/j.biortech.2023.129372}, pmid = {37343800}, issn = {1873-2976}, abstract = {Wastewater containing excess phenolic compounds is considered a major environmental concern due to its adverse impacts on the ecosystem. In this work, an effort has been given to treat the p-cresol from wastewater using Recirculating Packed Bed Biofilm Reactor (RPBBR). The process parameters, namely inoculum dose, pH, and NaCl (w/v) concentration were optimized to enhance the specific growth and obtained to be 14 ml, 7.0, and 1% NaCl (w/100 ml), respectively. Maximum p-cresol removal efficiency of 99.36±0.2% was achieved at 100 mg L[-1] of p-cresol. First-order rate constants were found to be 0.70 day[-1] and 0.96 day[-1] for batch and continuous mode, respectively. The intermediates were analysed using FT-IR and GC-MS analysis. Pseudomonas fluorescens was used to assess bacterial toxicity and observed that the toxicity was reduced in case of treated wastewater. Finally, the performance of continuous RPBBR was better than the batch mode.}, } @article {pmid37343240, year = {2023}, author = {Kil, YS and You, J and Wendt, KL and King, JB and Cichewicz, RH}, title = {Resolving a Natural Product Cold Case: Elucidation of Fusapyrone Structure and Absolute Configuration and Demonstration of Their Fungal Biofilm Disrupting Properties.}, journal = {The Journal of organic chemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.joc.3c00765}, pmid = {37343240}, issn = {1520-6904}, abstract = {Fusapyrones are fungal metabolites, which have been reported to have broad-spectrum antibacterial and antifungal properties. Despite the first members of this chemical class being described three decades prior, many aspects of their structures have remained unresolved, thereby constraining efforts to fully understand structure-activity relationships within this metabolite family and impeding the design of streamlined syntheses. Among the main challenges posed by fusapyrones is the incorporation of several single and groups of stereocenters separated by atoms with freely rotating bonds, which have proven unyielding to spectroscopic analyses. In this study, we obtained a series of new (2-5 and 7-9) and previously reported fusapyrones (1 and 6), which were subjected to a combination of spectroscopic, chemical, and computational techniques enabling us to offer proposals for their full structures, as well as provide a pathway to reinterpreting the absolute configurations of other published fusapyrone metabolites. Biological testing of the fusapyrones revealed their abilities to inhibit and disrupt biofilms made by the human fungal pathogen, Candida albicans. These results show that fusapyrones reduce hyphae formation in C. albicans, as well as decrease the surface adherence capabilities of planktonic cells and cells transitioning into early-stage biofilm formation.}, } @article {pmid37343134, year = {2023}, author = {Ahmad-Mansour, N and Plumet, L and Pouget, C and Kissa, K and Dunyach-Remy, C and Sotto, A and Lavigne, JP and Molle, V}, title = {The ROSA-like prophage colonizing Staphylococcus aureus promotes intracellular survival, biofilm formation and virulence in a chronic wound environment.}, journal = {The Journal of infectious diseases}, volume = {}, number = {}, pages = {}, doi = {10.1093/infdis/jiad218}, pmid = {37343134}, issn = {1537-6613}, abstract = {The transition from colonization to invasion is critical in diabetic foot ulcer (DFU). S. aureus can colonize DFU, or invade the underlying tissues, causing serious infections. The ROSA-like prophage has previously been implicated in strain colonization characteristics of S. aureus isolates in uninfected ulcers. Here, we investigated this prophage in the S. aureus colonizing strain using an in vitro chronic wound medium (CWM) mimicking the chronic wound environment. CWM reduced bacterial growth and increased biofilm formation and virulence in a zebrafish model. Moreover, the ROSA-like prophage promoted intracellular survival of S. aureus colonizing strain in macrophages, keratinocytes and osteoblasts.}, } @article {pmid37342622, year = {2023}, author = {Shi, Y and Liao, C and Dai, F and Zhang, Y and Li, C and Liang, W}, title = {Vibrio splendidus Fur regulates virulence gene expression, swarming motility, and biofilm formation, affecting its pathogenicity in Apostichopus japonicus.}, journal = {Frontiers in veterinary science}, volume = {10}, number = {}, pages = {1207831}, pmid = {37342622}, issn = {2297-1769}, abstract = {Vibrio splendidus is an opportunistic pathogen that causes skin ulcer syndrome and results in huge losses to the Apostichopus japonicus breeding industry. Ferric uptake regulator (Fur) is a global transcription factor that affects varieties of virulence-related functions in pathogenic bacteria. However, the role of the V. splendidus fur (Vsfur) gene in the pathogenesis of V. splendidus remains unclear. Hence, we constructed a Vsfur knock-down mutant of the V. splendidus strain (MTVs) to investigate the role of the gene in the effect of biofilm, swarming motility, and virulence on A. japonicus. The result showed that the growth curves of the wild-type V. splendidus strain (WTVs) and MTVs were almost consistent. Compared with WTVs, the significant increases in the transcription of the virulence-related gene Vshppd mRNA were 3.54- and 7.33-fold in MTVs at the OD600 of 1.0 and 1.5, respectively. Similarly, compared with WTVs, the significant increases in the transcription of Vsm mRNA were 2.10- and 15.92-fold in MTVs at the OD600 of 1.0 and 1.5, respectively. On the contrary, the mRNA level of the flagellum assembly gene Vsflic was downregulated 0.56-fold in MTVs at the OD600 of 1.0 compared with the WTVs. MTVs caused delayed disease onset time and reduced A. japonicus mortality. The median lethal doses of WTVs and MTVs were 9.116 × 10[6] and 1.658 × 10[11] CFU·ml[-1], respectively. Compared with WTVs, the colonization abilities of MTVs to the muscle, intestine, tentacle, and coelomic fluid of A. japonicus were significantly reduced. Correspondingly, the swarming motility and biofilm formation in normal and iron-replete conditions were remarkably decreased compared with those of WTVs. Overall, these results demonstrate that Vsfur contributes to the pathogenesis of V. splendidus by regulating virulence-related gene expression and affecting its swarming and biofilm formation abilities.}, } @article {pmid37341619, year = {2023}, author = {Smith, HB and Mullins, AJ and Webster, G and Sapsford, D and Gaskin, P and Monis, PT and Hoefel, D and Saint, CP and Weightman, AJ}, title = {Sphingopyxis Species Isolated from Sand Filter Biofilm at an Australian Drinking Water Treatment Works.}, journal = {Microbiology resource announcements}, volume = {}, number = {}, pages = {e0024923}, doi = {10.1128/mra.00249-23}, pmid = {37341619}, issn = {2576-098X}, abstract = {Three strains isolated by geosmin enrichment from a sand filter in an Australian drinking water treatment works were genome sequenced to identify their taxonomic placement, and a bench-scale batch experiment confirmed their geosmin-degrading capability. Using the average nucleotide identity based on the MUMmer algorithm (ANIm), pairwise digital DNA-DNA hybridization (dDDH), and phylogenomic analyses, the strains were identified as Sphingopyxis species.}, } @article {pmid37341603, year = {2023}, author = {Vo, N and Sidner, BS and Yu, Y and Piepenbrink, KH}, title = {Type IV Pilus-Mediated Inhibition of Acinetobacter baumannii Biofilm Formation by Phenothiazine Compounds.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0102323}, doi = {10.1128/spectrum.01023-23}, pmid = {37341603}, issn = {2165-0497}, abstract = {Infections by pathogenic Acinetobacter species represent a significant burden on the health care system, despite their relative rarity, due to the difficulty of treating infections through oral antibiotics. Multidrug resistance is commonly observed in clinical Acinetobacter infections and multiple molecular mechanisms have been identified for this resistance, including multidrug efflux pumps, carbapenemase enzymes, and the formation of bacterial biofilm in persistent infections. Phenothiazine compounds have been identified as a potential inhibitor of type IV pilus production in multiple Gram-negative bacterial species. Here, we report the ability of two phenothiazines to inhibit type IV pilus-dependent surface (twitching) motility and biofilm formation in multiple Acinetobacter species. Biofilm formation was inhibited in both static and continuous flow models at micromolar concentrations without significant cytotoxicity, suggesting that type IV pilus biogenesis was the primary molecular target for these compounds. These results suggest that phenothiazines may be useful lead compounds for the development of biofilm dispersal agents against Gram-negative bacterial infections. IMPORTANCE Acinetobacter infections are a growing burden on health care systems worldwide due to increasing antimicrobial resistance through multiple mechanisms. Biofilm formation is an established mechanism of antimicrobial resistance, and its inhibition has the potential to potentiate the use of existing drugs against pathogenic Acinetobacter. Additionally, as discussed in the manuscript, anti-biofilm activity by phenothiazines has the potential to help to explain their known activity against other bacteria, including Staphylococcus aureus and Mycobacterium tuberculosis.}, } @article {pmid37339905, year = {2023}, author = {Zhong, XC and Ouyang, X and Liao, YB and Tao, MZ and Peng, J and Long, ZQ and Gao, XJ and Cao, Y and Luo, MH and Peng, GJ and Zhou, ZX and Lei, GX}, title = {[Research progress on biofilm microecology in chronic suppurative otitis media].}, journal = {Zhonghua er bi yan hou tou jing wai ke za zhi = Chinese journal of otorhinolaryngology head and neck surgery}, volume = {58}, number = {6}, pages = {621-625}, doi = {10.3760/cma.j.cn115330-20230412-00167}, pmid = {37339905}, issn = {1673-0860}, support = {2021SK52202//The Guidance Fund of Hunan Province in Clinical Medical Technology Innovation/ ; 202207012466, B202313018285, B2019144, D202307018246, D202307018236//Scientific Research Project of Hunan Provincial Health Commission/ ; 22A0587//Key Project Supported by Hunan Provincial Department of Education/ ; JCYJ2021103, JCYJ2021109//Chenzhou Science and Technology Innovation Capability Cultivation Program/ ; 3664//Hunan College Students' Innovation and Entrepreneurship Training Program in 2021/ ; }, mesh = {Humans ; *Otitis Media, Suppurative ; Chronic Disease ; Biofilms ; *Otitis Media ; }, } @article {pmid37339544, year = {2023}, author = {Min, K and Kim, EK and Han, HH and Eom, JS}, title = {The effect of intraoperative immersion solutions on acellular dermal matrix: Biofilm formation and mechanical property.}, journal = {Journal of plastic, reconstructive & aesthetic surgery : JPRAS}, volume = {84}, number = {}, pages = {191-202}, doi = {10.1016/j.bjps.2023.05.025}, pmid = {37339544}, issn = {1878-0539}, abstract = {BACKGROUND: Acellular dermal matrix (ADM) is generally used on implant-based breast operations; However, it can increase surgical site infection. Many immersion solutions are applied to ADM, however, the most effective solution is unknown. The purpose of this study is to determine the effect of different solutions on the biofilm formation and mechanical properties of ADM.

METHODS: Aseptic porcine-derived ADMs were immersed in 5 different solutions for 30 min; sterile normal saline, 10% povidone-iodine, 0.5% chlorhexidine, antibiotics (cefazolin, gentamicin, and vancomycin), and taurolidine. They are transferred to 10 ml suspension of methicillin-sensitive/resistant Staphylococcus aureus (MSSA/MRSA) or Staphylococcus epidermidis and an overnight culture was performed. After rinsing and sonication to obtain the biofilm on ADM, colony forming unit (CFU) was measured. In addition, the maximum load before ADM deformation and the elongation length of ADM at the start of the maximum load was determined.

RESULTS: Regardless of strains, povidone-iodine, chlorhexidine, and taurolidine group had lower CFUs than the saline group with statistical significance. Meanwhile, the antibiotics group did not show statistical difference from the saline group. Moreover, only taurolidine group showed higher tensile strength (MRSA, p = 0.0003; S. epidermidis, p = 0.0023) and elongation length (MSSA, p = 0.0015) than the saline group. The antibiotics and chlorhexidine group yielded lower tensile strength and elongation length than the povidone-iodine and taurolidine groups.

CONCLUSIONS: It was suggested that the 10% povidone-iodine or taurolidine solution is effective. In contrast, the antibiotics solution could be considered as an effective intraoperative solution.}, } @article {pmid37338857, year = {2023}, author = {Wackett, LP and McKnight, }, title = {Web alert: Microbial biofilm catalysis.}, journal = {Microbial biotechnology}, volume = {16}, number = {7}, pages = {1577-1578}, doi = {10.1111/1751-7915.14299}, pmid = {37338857}, issn = {1751-7915}, mesh = {Catalysis ; *Biofilms ; }, } @article {pmid37337909, year = {2023}, author = {Ajetunmobi, OH and Chaturvedi, AK and Badali, H and Vaccaro, A and Najvar, L and Wormley, FL and Wiederhold, NP and Patterson, TF and Lopez-Ribot, JL}, title = {Screening the medicine for malaria venture's Pandemic Response Box to identify novel inhibitors of Candida albicans and Candida auris biofilm formation.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13342}, pmid = {37337909}, issn = {1600-0463}, abstract = {Candida spp. are opportunistic yeasts capable of forming biofilms, which contribute to resistance, increasing the urgency for new effective antifungal therapies. Repurposing existing drugs could significantly accelerate the development of novel therapies against candidiasis. We screened the Pandemic Response Box containing 400 diverse drug-like molecules active against bacteria, viruses or fungi, for inhibitors of Candida albicans and Candida auris biofilm formation. Initial hits were identified based on the demonstration of >70% inhibitory activity. Dose-response assays were used to confirm the antifungal activity of initial hits and establish their potency. The spectrum of antifungal activity of the leading compounds was determined against a panel of medically important fungi, and the in vivo activity of the leading repositionable agent was evaluated in murine models of C. albicans and C. auris systemic candidiasis. The primary screening identified 20 hit compounds, and their antifungal activity and potency against C. albicans and C. auris were validated using dose-response measurements. From these experiments, the rapalog everolimus, emerged as the leading repositionable candidate. Everolimus displayed potent antifungal activity against different Candida spp., but more moderate levels of activity against filamentous fungi. Treatment with everolimus increased survival of mice infected with C. albicans, but not those with C. auris. The screening of the Pandemic Response Box resulted in the identification of several drugs with novel antifungal activity, with everolimus emerging as the main repositionable candidate. Further in vitro and in vivo studies are needed to confirm its potential therapeutic use.}, } @article {pmid37332683, year = {2023}, author = {Žiemytė, M and Escudero, A and Díez, P and Ferrer, MD and Murguía, JR and Martí-Centelles, V and Mira, A and Martínez-Máñez, R}, title = {Ficin-Cyclodextrin-Based Docking Nanoarchitectonics of Self-Propelled Nanomotors for Bacterial Biofilm Eradication.}, journal = {Chemistry of materials : a publication of the American Chemical Society}, volume = {35}, number = {11}, pages = {4412-4426}, pmid = {37332683}, issn = {0897-4756}, abstract = {Development of bioinspired nanomotors showing effective propulsion and cargo delivery capabilities has attracted much attention in the last few years due to their potential use in biomedical applications. However, implementation of this technology in realistic settings is still a barely explored field. Herein, we report the design and application of a multifunctional gated Janus platinum-mesoporous silica nanomotor constituted of a propelling element (platinum nanodendrites) and a drug-loaded nanocontainer (mesoporous silica nanoparticle) capped with ficin enzyme modified with β-cyclodextrins (β-CD). The engineered nanomotor is designed to effectively disrupt bacterial biofilms via H2O2-induced self-propelled motion, ficin hydrolysis of the extracellular polymeric matrix (EPS) of the biofilm, and controlled pH-triggered cargo (vancomycin) delivery. The effective synergic antimicrobial activity of the nanomotor is demonstrated in the elimination of Staphylococcus aureus biofilms. The nanomotor achieves 82% of EPS biomass disruption and a 96% reduction in cell viability, which contrasts with a remarkably lower reduction in biofilm elimination when the components of the nanomotors are used separately at the same concentrations. Such a large reduction in biofilm biomass in S. aureus has never been achieved previously by any conventional therapy. The strategy proposed suggests that engineered nanomotors have great potential for the elimination of biofilms.}, } @article {pmid37331691, year = {2023}, author = {Arshad, R and Razlansari, M and Maryam Hosseinikhah, S and Tiwari, A and Ajalli, N and Ezra Manicum, AL and Throat, N and Rahdar, A and Zhu, Y and Tabish, TA}, title = {Antimicrobial and anti-biofilm activities of bio-inspired nanomaterials for wound healing applications.}, journal = {Drug discovery today}, volume = {}, number = {}, pages = {103673}, doi = {10.1016/j.drudis.2023.103673}, pmid = {37331691}, issn = {1878-5832}, abstract = {Chronic wounds are ubiquitously inhabited by bacteria, and they remain a challenge as they cause significant discomfort and because their treatment consumes huge clinical resources. To reduce the burden that chronic wounds place upon both patients and health services, a wide variety of approaches have been devised and investigated. Bioinspired nanomaterials have shown great success in wound healing when compared to existing approaches, showing better ability to mimic natural extracellular matrix (ECM) components and thus to promote cell adhesion, proliferation, and differentiation. Wound dressings that are based on bioinspired nanomaterials can be engineered to promote anti-inflammatory mechanisms and to inhibit the formation of microbial biofilms. We consider the extensive potential of bioinspired nanomaterials in wound healing, revealing a scope beyond that covered previously {AuQ: Edit OK?} .}, } @article {pmid37331555, year = {2023}, author = {Ou, Z and Chen, X and Wu, X and Zhou, C and Zhang, K and Luo, J and Fang, F and Sun, Y and Li, M and Feng, Q}, title = {N-acyl homoserine lactone mediating initial adhesion of microalgal biofilm formation.}, journal = {Environmental research}, volume = {}, number = {}, pages = {116446}, doi = {10.1016/j.envres.2023.116446}, pmid = {37331555}, issn = {1096-0953}, abstract = {While pioneering methods have demonstrated that bacterial N-acyl homoserine lactone (AHL) signaling molecules can influence the growth and self-aggregation of suspended microalgae, whether AHLs can affect the initial adhesion to a carrier has remained an open question. Here we revealed that the microalgae exhibited different adhesion potential under AHL mediation, where the performance was affiliated to both AHL types and concentrations. The result can be well explained by the interaction energy theory, where the energy barrier between the carriers and the cells varied due to AHL mediation. Depth analyses revealed that AHL acted through modifying the properties of the surface electron donor of the cells, which were dependent upon three major components, i.e., extracellular protein (PN) secretion, the PN secondary structure, and the PN amino acid composition. These findings expand the known diversity of AHLs mediation on microalgal initial adhesion and metabolisms, which may interface with other major cycles and become helpful to theoretically guide the application of AHLs in microalgal culture and harvesting.}, } @article {pmid37331492, year = {2023}, author = {Radojević, I and Jakovljević, V and Grujić, S and Ostojić, A and Ćirković, K}, title = {Biofilm formation by selected microbial strains isolated from wastewater and their consortia: mercury resistance and removal potential.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104092}, doi = {10.1016/j.resmic.2023.104092}, pmid = {37331492}, issn = {1769-7123}, abstract = {Wastewater often contains an increased amount of mercury and, at the same time, resistant microorganisms. During wastewater treatment, a biofilm of indigenous microorganisms is often unavoidable. Therefore, the objective of this research is to isolate and identify microorganisms from wastewater and investigate their ability to form biofilms for possible application in mercury removal processes. The resistance of planktonic cells and their biofilms to the effects of mercury was investigated using Minimum Biofilm Eradication Concentration-High Throughput Plates. The formation of biofilms and the degree of resistance to mercury were confirmed in polystyrene microtiter plates with 96 wells. Biofilm on AMB Media carriers (Assisting Moving Bad Media) was quantified using the Bradford protein assay. The removal of mercury ions by biofilms formed on AMB Media carriers of selected isolates and their consortia was determined by a removal test in Erlenmeyer flasks simulating MBBR. All isolates in planktonic form showed some degree of resistance to mercury. The most resistant microorganisms (Enterobacter cloacae, Klebsiella oxytoca, Serratia odorifera, and Saccharomyces cerevisiae) were tested for their ability to form biofilms in the presence and absence of mercury, both in polystyrene plates and on ABM carriers. The results showed that among planktonic forms, K. oxytoca was the most resistant. A biofilm of the same microorganisms was more than 10-fold resistant. Most consortia biofilms had MBEC values > 100000 μg/mL. Among individual biofilms, E. cloacae showed the highest mercury removal efficiency (97.81% for 10 days). Biofilm consortia composed of three species showed the best ability to remove mercury (96.64% to 99.03% for 10 days). This study points to the importance of consortia of different types of wastewater microorganisms in the form of biofilms and suggests that they can be used to remove mercury in wastewater treatment bioreactors.}, } @article {pmid37330291, year = {2023}, author = {Sønderby, TV and Louros, NN and Khodaparast, L and Khodaparast, L and Madsen, DJ and Olsen, WP and Moonen, N and Nagaraj, M and Sereikaite, V and Strømgaard, K and Rousseau, F and Schymkowitz, J and Otzen, DE}, title = {Sequence-targeted Peptides Divert Functional Bacterial Amyloid Towards Destabilized Aggregates and Reduce Biofilm Formation.}, journal = {Journal of molecular biology}, volume = {}, number = {}, pages = {168039}, doi = {10.1016/j.jmb.2023.168039}, pmid = {37330291}, issn = {1089-8638}, abstract = {Functional bacterial amyloid provides structural stability in biofilm, making it a promising target for anti-biofilm therapeutics. Fibrils formed by CsgA, the major amyloid component in E. coli are extremely robust and can withstand very harsh conditions. Like other functional amyloids, CsgA contains relatively short aggregation-prone regions (APR) which drive amyloid formation. Here, we demonstrate the use of aggregation-modulating peptides to knock down CsgA protein into aggregates with low stability and altered morphology. Remarkably, these CsgA-peptides also modulate fibrillation of the unrelated functional amyloid protein FapC from Pseudomonas, possibly through recognition of FapC segments with structural and sequence similarity with CsgA. The peptides also reduce the level of biofilm formation in E. coli and P. aeruginosa, demonstrating the potential for selective amyloid targeting to combat bacterial biofilm.}, } @article {pmid37329540, year = {2023}, author = {Ma, C and Zhang, Y and Lei, J and Zhang, J and Li, F and He, X and Yuan, J and Li, W and Chen, W}, title = {Programmed Cell Death Protein 1/Programmed Cell Death Ligand 1 Signaling Pathway Mediated Interleukin-10 and Bacterial Biofilm Formation to Drug Resistance Mechanism of Pneumoniae Meningitis.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {4}, pages = {105-111}, doi = {10.14715/cmb/2023.69.4.16}, pmid = {37329540}, issn = {1165-158X}, mesh = {Animals ; Mice ; *Interleukin-10 ; Programmed Cell Death 1 Receptor ; B7-H1 Antigen ; Ligands ; Interferon-gamma/metabolism ; Signal Transduction ; Streptococcus pneumoniae ; *Pneumonia ; Apoptosis ; Drug Resistance ; Penicillins ; }, abstract = {It aimed to explore the resistance and biofilm formation characteristics of pneumococcal meningitis (PM) and the mechanism of programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) signaling pathway (SPW). Firstly, the drug susceptibility test of 32 Streptococcus pneumoniae strains isolated from patients with PM and the biofilm semi-quantitative determination was performed. Then, the PM mouse model was constructed. The differences in brain morphology, blood-brain barrier (BBB) permeability, water content, cytokines such as interferon-γ (IFN-γ), interleukin-10 (IL-10), and chemokine C-X-C ligand 10 (CXCL10), and levels of PD-1 and PD-L1 in the normal control (NC), sham operation, PM, and PD-1 antibody (PM + PD-1 Ab)groups were compared and analyzed. The results showed that streptococcus pneumoniae had multidrug resistance, and the thickness of biofilm decreased with the increase of penicillin minimum inhibitory concentration (MIC). Compared with the NC and Sham groups, BBB permeability, water content, levels of IFN-γ and IL-10, and PD-1 and PD-L1 were signally increased in the PM and PM + PD-1 Ab groups, while CXCL10 level was decreased, exhibiting differences withP<0.05. Based on the PM group, BBB permeability, water content, levels of IFN-γ and CXCL10, and PD-1 and PD-L1 were remarkably decreased in the PM + PD-1 Ab group, while the IL-10 level was observably increased (P<0.05). Therefore, high-MIC penicillin could inhibit the thickness of Streptococcus pneumoniae biofilm, while blocking the PD-1/PD-L1 pathway exerted an improving effect on the PM symptoms.}, } @article {pmid37329438, year = {2023}, author = {Chakraborty, S and Mondal, S}, title = {Halotolerant Citrobacter sp. remediates salinity stress and promotes the growth of Vigna radiata (L) by secreting extracellular polymeric substances (EPS) and biofilm formation: a novel active cell for microbial desalination cell (MDC).}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37329438}, issn = {1618-1905}, abstract = {To address soil salinization and its impact on crop production, microbial desalination cells (MDCs) offer a promising solution. These bioelectrochemical systems integrate desalination and wastewater treatment through microbial activity. A halotolerant beneficial bacterial strain called Citrobacter sp. strain KUT (CKUT) was isolated from India's salt desert Run of Kutch, Gujrat, highlighting its potential application in combating soil salinization. CKUT exhibits high salt tolerance and has the ability to produce extracellular polymeric substances (EPS) at a concentration of 0.04 mg/ml. It forms biofilm that enable it to withstand up to 10% NaCl concentration. Additionally, CKUT shows promise in remediating salinity levels, reducing it from 4.5 to 2.7 gL[-1]. These characteristics are driven by biofilm formation and EPS production. In an experiment where V. radiata L. seedlings were inoculated with CKUT, the treated plants exhibited enhanced chlorophyll content, growth, and overall plant characteristics compared to seedlings treated with sodium chloride (NaCl). These improvements included increased shoot length (150 mm), root length (40 mm), and biomass. This indicates that CKUT treatment has the potential to enhance the suitability of V. radiata and other crops for cultivation in saline lands, effectively addressing the issue of soil salinization. Furthermore, integrating CKUT into microbial desalination cells (MDCs) offers an opportunity for freshwater production from seawater, contributing to sustainable agriculture by promoting improved crop growth and increased yield in areas prone to salinity. HIGHLIGHTS : • Soil salinization reduces crop yield, including Vigna radiata L. • Citrobacter sp. strain KUT (CKUT) is a halotolerant bacterium isolated from the salt desert Run of Kutch, Gujarat, which can tolerate high salt concentrations. • CKUT mitigates salinity by producing extracellular polymeric substances (EPS) and forming biofilms. • CKUT treatment demonstrated increased plant growth, biomass, and chlorophyll content under salinity stress, showcasing its potential in microbial desalination cell (MDC) for enhancing crop yield in salinized soils.}, } @article {pmid37329360, year = {2023}, author = {Seebach, E and Kraus, FV and Elschner, T and Kubatzky, KF}, title = {Staphylococci planktonic and biofilm environments differentially affect osteoclast formation.}, journal = {Inflammation research : official journal of the European Histamine Research Society ... [et al.]}, volume = {}, number = {}, pages = {}, pmid = {37329360}, issn = {1420-908X}, abstract = {INTRODUCTION: The pathophysiology of chronic implant-related bone infections is characterized by an increase in osteoclast numbers and enhanced bone resorption. Biofilms are a major reason for chronicity of such infections as the biofilm matrix protects bacteria against antibiotics and impairs the function of immune cells. Macrophages are osteoclast precursor cells and therefore linked to inflammation and bone destruction.

OBJECTIVE AND METHOD: Investigations on the impact of biofilms on the ability of macrophages to form osteoclasts are yet missing and we, therefore, analyzed the effect of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) planktonic and biofilm environments on osteoclastogenesis using RAW 264.7 cells and conditioned media (CM).

RESULTS: Priming with the osteoclastogenic cytokine RANKL before CM addition enabled the cells to differentiate into osteoclasts. This effect was highest in SE planktonic or SA biofilm CM. Simultaneous stimulation with CM and RANKL, however, suppressed osteoclast formation and resulted in formation of inflammation-associated multinucleated giant cells (MGCs) which was most pronounced in SE planktonic CM.

CONCLUSION: Our data indicate that the biofilm environment and its high lactate levels are not actively promoting osteoclastogenesis. Hence, the inflammatory immune response against planktonic bacterial factors through Toll-like receptors seems to be the central cause for the pathological osteoclast formation. Therefore, immune stimulation or approaches that aim at biofilm disruption need to consider that this might result in enhanced inflammation-mediated bone destruction.}, } @article {pmid37327931, year = {2023}, author = {Raj, V and Raorane, CJ and Lee, JH and Lee, J}, title = {Gum Arabic polysaccharide embedded L-cysteine capped copper oxide nanocarriers selectively inhibit fluconazole-resistant C. albicans biofilm and remove the toxic dye from wastewater.}, journal = {International journal of biological macromolecules}, volume = {244}, number = {}, pages = {125361}, doi = {10.1016/j.ijbiomac.2023.125361}, pmid = {37327931}, issn = {1879-0003}, abstract = {Copper oxide nanocarriers have attracted increasing interest in the scientific community, including antimicrobial applications. Candida biofilm developed causes serious clinical problems, leading to drug failure caused by its inherent drug tolerance. Nanocarriers are a good alternative approach to solving this challenge because of their excellent penetration power inside biofilms. Hence, main objectives of this research were to prepare gum arabic-embedded L-cysteine-capped copper oxide nanocarriers (GCCuO NCs) and tested against C. albicans and explore another application. To achieve the main research objectives, GCCuO NCs were synthesized and investigated for antibiofilm potency against C. albicans. Various methods were employed to measure antibiofilm potency such as biofilm assay etc., of NCs. The nano size of GCCuO NCs is advantageous for augmenting penetration power and retention into biofilms. GCCuO NCs at 100 μg/mL exhibited significant antibiofilm activity against the C. albicans DAY185 by switching of yeast-to-hyphae and gene perturbation. The level of CR dye adsorption was 58.96 % using 30 μg/mL of NCs. Based on effective C. albicans biofilm inhibition and CR dye adsorption capacity of NCs, it can be suggested that present research work opens an innovative path to treat biofilm-associated fungal infections, and these NCs can be used for environmental remedies.}, } @article {pmid37327822, year = {2023}, author = {Wang, L and Zhou, W and Zhang, M and Zheng, Z and Zhao, S and Xing, C and Jia, J and Liu, C}, title = {Environmental ammonia analysis based on exclusive nitrification by nitrifying biofilm screened from natural bioresource.}, journal = {Chemosphere}, volume = {336}, number = {}, pages = {139221}, doi = {10.1016/j.chemosphere.2023.139221}, pmid = {37327822}, issn = {1879-1298}, abstract = {Biofilm-based biological nitrification is widely used for ammonia removal, while hasn't been explored for ammonia analysis. The stumbling block is the coexist of nitrifying and heterotrophic microbes in real environment resulting in non-specific sensing. Herein, an exclusive ammonia sensing nitrifying biofilm was screened from natural bioresource, and a bioreaction-detection system for the on-line analysis of environmental ammonia based on biological nitrification was reported. The nitrifying microbes were aggregated into a nitrifying biofilm through a result-oriented bioresource enrichment strategy. The predominant nitrifying population and progressive surface reaction in the plug flow bioreactor led to the exclusive and exhaustive ammonia biodegradation for the establishment of a novel analytical method. The on-line ammonia monitoring prototype achieved complete biodegradation for determining ammonium nitrogen within 5 min and showed exceptional reliability in long-term real sample measurements without frequent calibration. This work offers a low-threshold natural screening paradigm for developing sustainable bioresource-based analytical technologies.}, } @article {pmid37326621, year = {2023}, author = {Henderson, SR and Geoghegan, JA}, title = {The A domain of clonal complex 1-type fibronectin binding protein B promotes adherence and biofilm formation in Staphylococcus aureus.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {6}, pages = {}, doi = {10.1099/mic.0.001348}, pmid = {37326621}, issn = {1465-2080}, mesh = {Humans ; *Staphylococcus aureus/genetics/metabolism ; Ligands ; Adhesins, Bacterial/genetics/chemistry/metabolism ; Bacterial Adhesion ; Carrier Proteins/metabolism ; Protein Binding ; *Staphylococcal Infections/microbiology ; Fibronectins/metabolism ; Biofilms ; Bacterial Proteins/metabolism ; }, abstract = {Adhesive interactions between Staphylococcus aureus and the host rely on cell-wall-anchored proteins such as fibronectin-binding protein B (FnBPB). Recently we showed that the FnBPB protein expressed by clonal complex (CC) 1 isolates of S. aureus mediates bacterial adhesion to corneodesmosin. The proposed ligand-binding region of CC1-type FnBPB shares just 60 % amino acid identity with the archetypal FnBPB protein from CC8. Here we investigated ligand binding and biofilm formation by CC1-type FnBPB. We found that the A domain of FnBPB binds to fibrinogen and corneodesmosin and identified residues within the hydrophobic ligand trench in the A domain that are essential for the binding of CC1-type FnBPB to ligands and during biofilm formation. We further investigated the interplay between different ligands and the influence of ligand binding on biofilm formation. Overall, our study provides new insights into the requirements for CC1-type FnBPB-mediated adhesion to host proteins and FnBPB-mediated biofilm formation in S. aureus.}, } @article {pmid37325271, year = {2023}, author = {Shahzad, HMA and Khan, SJ and Khan, M and Schönberger, H and Weber, FA}, title = {Performance and cost-benefit analysis of anaerobic moving bed biofilm reactor for pretreatment of textile wastewater.}, journal = {The Korean journal of chemical engineering}, volume = {40}, number = {6}, pages = {1389-1400}, pmid = {37325271}, issn = {0256-1115}, abstract = {Performance of an anaerobic moving bed biofilm reactor (AnMBBR) was evaluated for pretreatment of real textile desizing wastewater at organic loading rate (OLR) of 1±0.05 to 6.3±0.37 kgCOD/m[3]/d. After OLR optimization, the performance of AnMBBR was evaluated for biodegradation of reactive dyes. AnMBBR was operated under a mesophilic temperature range of 30 to 36 °C, while the oxidation-reduction potential (ORP) and pH were in the range of 504 to 594 (-mV) and 6.98 to 7.28, respectively. By increasing the OLR from 1±0.05 to 6.3±0.37 kgCOD/m[3]/d, COD and BOD5 removal was decreased from 84 to 39% and 89 to 49%, respectively. While the production of biogas was increased from 0.12 to 0.83 L/L·d up to an optimum OLR of 4.9±0.43 kgCOD/m[3]/d. With increase in the dye concentration in the feed, COD, BOD5, color removal and biogas production reduced from 56, 63, 70% and 0.65 L/L·d to 34, 43, 41% and 0.08 L/L·d, respectively. Based on the data obtained, a cost-benefit analysis of AnMBBR was also investigated for the pretreatment of real textile desizing wastewater. Cost estimation of anaerobic pretreatment of textile desizing wastewater indicated a net profit of 21.09 million PKR/yr (114,000 €/yr) and a potential payback period of 2.54 years.}, } @article {pmid37325022, year = {2023}, author = {Li, X and Kong, R and Wang, J and Wu, J and Wang, X}, title = {Matrix Producing Cells Induce the Morphological Difference in the Bacillus subtilis Biofilm.}, journal = {Indian journal of microbiology}, volume = {63}, number = {2}, pages = {197-207}, pmid = {37325022}, issn = {0046-8991}, abstract = {There is a 'coffee ring' in the Bacillus subtilis biofilm center, and the colony biofilm morphologies are distinct inside and outside the 'coffee ring'. In this paper, we study this morphological difference and explain the reasons of the 'coffee ring' formation and further the causes to the morphological variation. We developed a quantitative method to characterize the surface morphology, the outer area is thicker than the inner area of the 'coffee ring', and the thickness amplitude in outer area is larger than inner area of the 'coffee ring'. We adopt a logistic growth model to obtain how the environmental resistance influence the colony biofilm thickness. Dead cells provide gaps for stress release and make folds formation in colony biofilm. we developed a technique for optical imaging and matching cells with the BRISK algorithm to capture the distribution and movement of motile cells and matrix producing cells in the colony biofilm. Matrix producing cells are mainly distribute in the outside of the 'coffee ring', and the extracellular matrix (ECM) prevents the motile cells moving outward from center. Motile cells mainly locate inside the ring, a small amount of dead motile cells outside the 'coffee ring' give rise to radial folds formation. There are no ECM blocking cell movements inside the ring, which result in uniform folds formation. The distribution of ECM and different phenotypes lead to the formation of the 'coffee ring', which is verified by using eps and flagellar mutants.}, } @article {pmid37324421, year = {2023}, author = {Li, S and Wang, Y and Wang, S and Xie, J and Fu, T and Li, S}, title = {In situ gelling hydrogel loaded with berberine liposome for the treatment of biofilm-infected wounds.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1189010}, pmid = {37324421}, issn = {2296-4185}, abstract = {Background: In recent years, the impact of bacterial biofilms on traumatic wounds and the means to combat them have become a major research topic in the field of medicine. The eradication of biofilms formed by bacterial infections in wounds has always been a huge challenge. Herein, we developed a hydrogel with the active ingredient berberine hydrochloride liposomes to disrupt the biofilm and thereby accelerate the healing of infected wounds in mice. Methods: We determined the ability of berberine hydrochloride liposomes to eradicate the biofilm by means of studies such as crystalline violet staining, measuring the inhibition circle, and dilution coating plate method. Encouraged by the in vitro efficacy, we chose to coat the berberine hydrochloride liposomes on the Poloxamer range of in-situ thermosensitive hydrogels to allow fuller contact with the wound surface and sustained efficacy. Eventually, relevant pathological and immunological analyses were carried out on wound tissue from mice treated for 14 days. Results: The final results show that the number of wound tissue biofilms decreases abruptly after treatment and that the various inflammatory factors in them are significantly reduced within a short period. In the meantime, the number of collagen fibers in the treated wound tissue, as well as the proteins involved in healing in the wound tissue, showed significant differences compared to the model group. Conclusion: From the results, we found that berberine liposome gel can accelerate wound healing in Staphylococcus aureus infections by inhibiting the inflammatory response and promoting re-epithelialization as well as vascular regeneration. Our work exemplifies the efficacy of liposomal isolation of toxins. This innovative antimicrobial strategy opens up new perspectives for tackling drug resistance and fighting wound infections.}, } @article {pmid37323400, year = {2023}, author = {Bag, K and Pal, AK and Basu, S and Singla, M and Sarkar, B and Chatterji, D and Maiti, PK and Ghosh, A and Jayaraman, N}, title = {C-4-Modified Isotetrones Prevent Biofilm Growth and Persister Cell Resuscitation in Mycobacterium smegmatis.}, journal = {ACS omega}, volume = {8}, number = {23}, pages = {20513-20523}, pmid = {37323400}, issn = {2470-1343}, abstract = {Hyperphosphorylated nucleotide (p)ppGpp, synthesized by Rel protein, regulates the stringent response pathway responsible for biofilm and persister cell growth in mycobacteria. The discovery of vitamin C as an inhibitor of Rel protein activities raises the prospect of tetrone lactones to prevent such pathways. The closely related isotetrone lactone derivatives are identified herein as inhibitors of the above processes in a mycobacterium. Synthesis and biochemical evaluations show that an isotetrone possessing phenyl substituent at C-4 inhibit the biofilm formation at 400 μg mL[-1], 84 h post-exposure, followed by moderate inhibition by the isotetrone possessing the p-hydroxyphenyl substituent. The latter isotetrone inhibits the growth of persister cells at 400 μg mL[-1] f.c. when monitored for 2 weeks, under PBS starvation. Isotetrones also potentiate the inhibition of antibiotic-tolerant regrowth of cells by ciprofloxacin (0.75 μg mL[-1]) and thus act as bioenhancers. Molecular dynamics studies show that isotetrone derivatives bind to the RelMsm protein more efficiently than vitamin C at a binding site possessing serine, threonine, lysine, and arginine.}, } @article {pmid37322124, year = {2023}, author = {Taglialegna, A}, title = {A killer biofilm.}, journal = {Nature reviews. Microbiology}, volume = {}, number = {}, pages = {}, pmid = {37322124}, issn = {1740-1534}, } @article {pmid37322086, year = {2023}, author = {Watchaputi, K and Jayasekara, LACB and Ratanakhanokchai, K and Soontorngun, N}, title = {Inhibition of cell cycle-dependent hyphal and biofilm formation by a novel cytochalasin 19,20‑epoxycytochalasin Q in Candida albicans.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {9724}, pmid = {37322086}, issn = {2045-2322}, mesh = {Humans ; *Candida albicans ; *Antifungal Agents/pharmacology ; Cytochalasins/pharmacology ; Cell Division ; Cell Cycle ; Hyphae ; Biofilms ; Lipids/pharmacology ; }, abstract = {Biofilm-mediated drug resistance is a key virulence factor of pathogenic microbes that cause a serious global health threat especially in immunocompromised individuals. Here, we investigated the antihyphal and antibiofilm activity of 19,20‑epoxycytochalasin Q (ECQ), a cytochalasin actin inhibitor isolated from medicinal mushroom Xylaria sp. BCC1067 against Candida albicans. Remarkably, 256 µg/ml of ECQ inhibited over 95% of C. albicans hyphal formation after 24 h-treatment. Combined ECQ and lipid-based biosurfactant effectively enhanced the antihyphal activity, lowering required ECQ concentrations. Hyphal fragmentation and reduction of biofilm biomass, shown by SEM and AFM visualization of ECQ-treated biofilms, were well corelated to the reduced metabolic activities of young and 24 h-preformed C. albicans biofilms. Induced intracellular accumulation of reactive oxygen species (ROS) also occurred in accompany with the leakage of shrunken cell membrane and defective cell wall at increasing ECQ concentrations. Transcriptomic analyses via RNA-sequencing revealed a massive change (> 1300 genes) in various biological pathways, following ECQ-treatment. Coordinated expression of genes, associated with cellular response to drugs, filamentous growth, cell adhesion, biofilm formation, cytoskeleton organization, cell division cycle, lipid and cell wall metabolisms was confirmed via qRT-PCR. Protein-protein association tool identified coupled expression between key regulators of cell division cyclin-dependent kinases (Cdc19/28) and a gamma-tubulin (Tub4). They coordinated ECQ-dependent hyphal specific gene targets of Ume6 and Tec1 during different phases of cell division. Thus, we first highlight the antihyphal and antibiofilm property of the novel antifungal agent ECQ against one of the most important life-threatening fungal pathogens by providing its key mechanistic detail in biofilm-related fungal infection.}, } @article {pmid37318927, year = {2023}, author = {Junejo, B and Eryilmaz, M and Rizvanoglu, SS and Palabiyik, IM and Ghumro, T and Mallah, A and Solangi, AR and Hyder, SI and Maleh, HK and Dragoi, EN}, title = {Pharmacological assessment of Co3O4, CuO, NiO and ZnO nanoparticles via antibacterial, anti-biofilm and anti-quorum sensing activities.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {87}, number = {11}, pages = {2840-2851}, doi = {10.2166/wst.2023.150}, pmid = {37318927}, issn = {0273-1223}, mesh = {Anti-Bacterial Agents/pharmacology/chemistry ; *Zinc Oxide/pharmacology/chemistry ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Oxides/chemistry ; *Anti-Infective Agents/pharmacology ; *Metal Nanoparticles/chemistry ; Bacteria ; }, abstract = {Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater.}, } @article {pmid37317319, year = {2023}, author = {de Sousa, T and Hébraud, M and Alves, O and Costa, E and Maltez, L and Pereira, JE and Martins, Â and Igrejas, G and Poeta, P}, title = {Study of Antimicrobial Resistance, Biofilm Formation, and Motility of Pseudomonas aeruginosa Derived from Urine Samples.}, journal = {Microorganisms}, volume = {11}, number = {5}, pages = {}, pmid = {37317319}, issn = {2076-2607}, support = {DFA/BD/5332/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {Pseudomonas aeruginosa causes urinary tract infections associated with catheters by forming biofilms on the surface of indwelling catheters. Therefore, controlling the spread of the bacteria is crucial to preventing its transmission in hospitals and the environment. Thus, our objective was to determine the antibiotic susceptibility profiles of twenty-five P. aeruginosa isolates from UTIs at the Medical Center of Trás-os-Montes and Alto Douro (CHTMAD). Biofilm formation and motility are also virulence factors studied in this work. Out of the twenty-five P. aeruginosa isolates, 16% exhibited multidrug resistance, being resistant to at least three classes of antibiotics. However, the isolates showed a high prevalence of susceptibility to amikacin and tobramycin. Resistance to carbapenem antibiotics, essential for treating infections when other antibiotics fail, was low in this study, Notably, 92% of the isolates demonstrated intermediate sensitivity to ciprofloxacin, raising concerns about its efficacy in controlling the disease. Genotypic analysis revealed the presence of various β-lactamase genes, with class B metallo-β-lactamases (MBLs) being the most common. The blaNDM, blaSPM, and blaVIM-VIM2 genes were detected in 16%, 60%, and 12% of the strains, respectively. The presence of these genes highlights the emerging threat of MBL-mediated resistance. Additionally, virulence gene analysis showed varying prevalence rates among the strains. The exoU gene, associated with cytotoxicity, was found in only one isolate, while other genes such as exoS, exoA, exoY, and exoT had a high prevalence. The toxA and lasB genes were present in all isolates, whereas the lasA gene was absent. The presence of various virulence genes suggests the potential of these strains to cause severe infections. This pathogen demonstrated proficiency in producing biofilms, as 92% of the isolates were found to be capable of doing so. Currently, antibiotic resistance is one of the most serious public health problems, as options become inadequate with the continued emergence and spread of multidrug-resistant strains, combined with the high rate of biofilm production and the ease of dissemination. In conclusion, this study provides insights into the antibiotic resistance and virulence profiles of P. aeruginosa strains isolated from human urine infections, highlighting the need for continued surveillance and appropriate therapeutic approaches.}, } @article {pmid37317305, year = {2023}, author = {Van Alin, A and Corbett, MK and Fathollahzadeh, H and Tjiam, MC and Putnis, A and Eksteen, J and Kaksonen, AH and Watkin, E}, title = {Klebsiella aerogenes Adhesion Behaviour during Biofilm Formation on Monazite.}, journal = {Microorganisms}, volume = {11}, number = {5}, pages = {}, pmid = {37317305}, issn = {2076-2607}, support = {DP200103243//Australian Research Council/ ; nil//Parker CRC for Integrated Hydrometallurgy Solutions/ ; }, abstract = {The adsorption behaviour of micro-organisms during the initial attachment stage of biofilm formation affects subsequent stages. The available area for attachment and the chemophysical properties of a surface affect microbial attachment performance. This study focused on the initial attachment behaviour of Klebsiella aerogenes on monazite by measuring the ratio of planktonic against sessile subpopulations (P:S ratio), and the potential role of extracellular DNA (eDNA). eDNA production, effects of physicochemical properties of the surface, particle size, total available area for attachment, and the initial inoculation size on the attachment behaviour were tested. K. aerogenes attached to monazite immediately after exposure to the ore; however, the P:S ratio significantly (p = 0.05) changed in response to the particle size, available area, and inoculation size. Attachment occurred preferentially on larger-sized (~50 µm) particles, and either decreasing the inoculation size or increasing the available area further promoted attachment. Nevertheless, a portion of the inoculated cells always remained in a planktonic state. K. aerogenes produced lower eDNA in response to the changed surface chemical properties when monazite was replaced by xenotime. Using pure eDNA to cover the monazite surface significantly (p ≤ 0.05) hindered bacterial attachment due to the repulsive interaction between the eDNA layer and bacteria.}, } @article {pmid37317195, year = {2023}, author = {Maksimova, Y and Zorina, A and Nesterova, L}, title = {Oxidative Stress Response and E. coli Biofilm Formation under the Effect of Pristine and Modified Carbon Nanotubes.}, journal = {Microorganisms}, volume = {11}, number = {5}, pages = {}, pmid = {37317195}, issn = {2076-2607}, support = {20-44-596002//RFBR and Perm Territory/ ; }, abstract = {The article investigates the expression of oxyR and soxS oxidative stress genes in E. coli under the effect of pristine multi-walled carbon nanotubes (MWCNTs) and pristine single-walled carbon nanotubes (SWCNTs), MWCNTs and SWCNTs functionalized with carboxyl groups (MWCNTs-COOH and SWCNTs-COOH, respectively), SWCNTs functionalized with amino groups (SWCNTs-NH2) and SWCNTs functionalized with octadecylamine (SWCNTs-ODA). Significant differences were found in the expression of the soxS gene, while no changes were observed in the expression level of the oxyR gene. The pro-oxidant effect of SWCNTs, SWCNTs-COOH, SWCNTs-NH2, and SWCNTs-ODA is presented, and the contrary antioxidant effect of pristine MWCNTs and MWCNTs-COOH in the presence of methyl viologen hydrate (paraquat) is shown. The article shows that SWCNTs-COOH, SWCNTs-NH2, and SWCNTs-ODA added to the medium generate the production of reactive oxygen species (ROS) in bacterial cells. SWCNTs-COOH intensified the E. coli biofilm formation, and the biofilm biomass exceeded the control by 25 times. Additionally, it is shown that the rpoS expression increased in response to MWCNTs-COOH and SWCNTs-COOH, and the effect of SWCNTs-COOH was more significant. SWCNTs-COOH and SWCNTs-NH2 initiated an increase in ATP concentration in the planktonic cells and a decrease in the biofilm cells. The atomic force microscopy (AFM) method showed that the volume of E. coli planktonic cells after the exposure to carbon nanotubes (CNTs) decreased compared to that without exposure, mainly due to a decrease in cell height. The absence of a strong damaging effect of functionalized SWCNTs on E. coli K12 cells, both in suspension and in biofilms, is shown. Contact with functionalized SWCNTs initiated the aggregation of the polymeric substances of the biofilms; however, the cells did not lyse. Among the studied CNTs, SWCNTs-COOH caused an increased expression of the soxS and rpoS, the formation of ROS, and stimulation of the biofilm formation.}, } @article {pmid37317124, year = {2023}, author = {D'Aquila, P and Sena, G and Crudo, M and Passarino, G and Bellizzi, D}, title = {Effect of Essential Oils of Apiaceae, Lamiaceae, Lauraceae, Myrtaceae, and Rutaceae Family Plants on Growth, Biofilm Formation, and Quorum Sensing in Chromobacterium violaceum, Pseudomonas aeruginosa, and Enterococcus faecalis.}, journal = {Microorganisms}, volume = {11}, number = {5}, pages = {}, pmid = {37317124}, issn = {2076-2607}, abstract = {The biological role played by essential oils extracted from aromatic plants is progressively being recognized. This study evaluated the potential antibacterial activity of ten essential oils against Chromobacterium violaceum, Pseudomonas aeruginosa, and Enterococcus faecalis by measuring their minimum inhibitory concentration. We found that essential oils exert different antimicrobial effects, with Origanum vulgare and Foeniculum vulgare demonstrating the most significant inhibitory effect on bacterial growth for C. violaceum and E. faecalis. The growth of P. aeruginosa was not affected by any essential oil concentration we used. Sub-inhibitory concentrations of essential oils reduced in C. violaceum and E. faecalis biofilm formation, violacein amount, and gelatinase activity, all of which are biomarkers of the Quorum Sensing process. These concentrations significantly affect the global methylation profiles of cytosines and adenines, thus leading to the hypothesis that the oils also exert their effects through epigenetic changes. Considering the results obtained, it is possible that essential oils can find a broad spectrum of applications in counteracting microbial contamination and preserving sterility of surfaces and foods, as well as inhibiting microbial growth of pathogens, alone or in combination with traditional antibiotics.}, } @article {pmid37316480, year = {2023}, author = {Armalytė, J and Čepauskas, A and Šakalytė, G and Martinkus, J and Skerniškytė, J and Martens, C and Sužiedėlienė, E and Garcia-Pino, A and Jurėnas, D}, title = {A polyamine acetyltransferase regulates the motility and biofilm formation of Acinetobacter baumannii.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {3531}, pmid = {37316480}, issn = {2041-1723}, mesh = {*Acinetobacter baumannii/genetics ; Acetyltransferases/genetics ; Polyamines ; Biofilms ; }, abstract = {Acinetobacter baumannii is a nosocomial pathogen highly resistant to environmental changes and antimicrobial treatments. Regulation of cellular motility and biofilm formation is important for its virulence, although it is poorly described at the molecular level. It has been previously reported that Acinetobacter genus specifically produces a small positively charged metabolite, polyamine 1,3-diaminopropane, that has been associated with cell motility and virulence. Here we show that A. baumannii encodes novel acetyltransferase, Dpa, that acetylates 1,3-diaminopropane, directly affecting the bacterium motility. Expression of dpa increases in bacteria that form pellicle and adhere to eukaryotic cells as compared to planktonic bacterial cells, suggesting that cell motility is linked to the pool of non-modified 1,3-diaminopropane. Indeed, deletion of dpa hinders biofilm formation and increases twitching motion confirming the impact of balancing the levels of 1,3-diaminopropane on cell motility. The crystal structure of Dpa reveals topological and functional differences from other bacterial polyamine acetyltransferases, adopting a β-swapped quaternary arrangement similar to that of eukaryotic polyamine acetyltransferases with a central size exclusion channel that sieves through the cellular polyamine pool. The structure of catalytically impaired DpaY128F in complex with the reaction product shows that binding and orientation of the polyamine substrates are conserved between different polyamine-acetyltransferases.}, } @article {pmid37315963, year = {2023}, author = {Olivan-Muro, I and Sarasa-Buisan, C and Guio, J and Arenas, J and Sevilla, E and Fillat, MF}, title = {Unbalancing Zur (FurB)-mediated homeostasis in Anabaena sp. PCC7120: Consequences on metal trafficking, heterocyst development and biofilm formation.}, journal = {Environmental microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1462-2920.16434}, pmid = {37315963}, issn = {1462-2920}, support = {E35_20R//Gobierno de Aragón/ ; 438 PID2019-104889GB-I00//Ministerio de Ciencia, Innovación y Universidades/ ; }, abstract = {Zinc is required for the activity of many enzymes and plays an essential role in gene regulation and redox homeostasis. In Anabaena (Nostoc) sp. PCC7120, the genes involved in zinc uptake and transport are controlled by the metalloregulator Zur (FurB). Comparative transcriptomics of a zur mutant (Δzur) with the parent strain unveiled unexpected links between zinc homeostasis and other metabolic pathways. A notable increase in the transcription of numerous desiccation tolerance-related genes, including genes involved in the synthesis of trehalose and the transference of saccharide moieties, among many others, was detected. Biofilm formation analysis under static conditions revealed a reduced capacity of Δzur filaments to form biofilms compared to the parent strain, and such capacity was enhanced when Zur was overexpressed. Furthermore, microscopy analysis revealed that zur expression is required for the correct formation of the envelope polysaccharide layer in the heterocyst, as Δzur cells showed reduced staining with alcian blue compared to Anabaena sp. PCC7120. We suggest that Zur is an important regulator of the enzymes involved in the synthesis and transport of the envelope polysaccharide layer, influencing heterocyst development and biofilm formation, both relevant processes for cell division and interaction with substrates in its ecological niche.}, } @article {pmid37315907, year = {2023}, author = {Shenkutie, AM and Gebrelibanos, D and Yao, M and Hundie, GB and Chow, FWN and Leung, PHM}, title = {Impairment of novel non-coding small RNA00203 inhibits biofilm formation and reduces biofilm-specific antibiotic resistance in Acinetobacter baumannii.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106889}, doi = {10.1016/j.ijantimicag.2023.106889}, pmid = {37315907}, issn = {1872-7913}, abstract = {Small RNAs (sRNAs) are post-transcriptional regulators of many biological processes in bacteria, including biofilm formation and antibiotic resistance. The mechanisms by which sRNA regulates the biofilm-specific antibiotic resistance in Acinetobacter baumannii have not yet been reported. This study aimed to investigate the influence of sRNA00203 (53 nucleotides) on biofilm formation, antibiotic susceptibility, and expression of genes associated with biofilm formation and antibiotic resistance. Our results showed that deletion of the sRNA00203-encoding gene substantially decreased the biomass of biofilm by 85%. Deletion of the sRNA00203-encoding gene also reduced the minimum biofilm inhibitory concentration for imipenem and ciprofloxacin by 1,024 and 128 folds, respectively. Besides, knocking out of sRNA00203 significantly downregulated genes involved in biofilm matrix synthesis (pgaB), efflux pump production (novel00738), lipopolysaccharide biosynthesis (novel00626), preprotein translocase subunit (secA), and the CRP transcriptional regulator. Overall, we found that suppression of sRNA00203 in an A. baumannii ST1894 strain impaired biofilm formation and sensitized the biofilm cells to imipenem and ciprofloxacin. As sRNA00203 was found to be conserved in A. baumannii, a therapeutic strategy targeting sRNA00203 may be a potential solution to the treatment of biofilm-associated infections caused by A. baumannii. To the best of our knowledge, this is the first study to show the impact of sRNA00203 on biofilm formation and biofilm-specific antibiotic resistance in A. baumannii.}, } @article {pmid37315906, year = {2023}, author = {Agyeman, AA and López-Causapé, C and Rogers, KE and Lucas, DD and Cortés-Lara, S and Gomis-Font, MA and Fraile-Ribot, P and Figuerola, J and Lang, Y and Franklyn, ERT and Lee, WL and Zhou, J and Zhang, Y and Bulitta, JB and Boyce, JD and Nation, RL and Oliver, A and Landersdorfer, CB}, title = {Ceftolozane/tazobactam plus tobramycin against free-floating and biofilm bacteria of hypermutable Pseudomonas aeruginosa epidemic strains: resistance mechanisms and synergistic activity: Running title: Ceftolozane/tazobactam plus tobramycin against Pseudomonas biofilm.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106887}, doi = {10.1016/j.ijantimicag.2023.106887}, pmid = {37315906}, issn = {1872-7913}, abstract = {Acute exacerbations of biofilm-associated Pseudomonas aeruginosa infections in cystic fibrosis have limited treatment options. Ceftolozane/tazobactam (alone and with a second antibiotic) has not yet been investigated against hypermutable clinical P. aeruginosa isolates in biofilm growth. This study aimed to evaluate, using an in vitro dynamic biofilm model, ceftolozane/tazobactam alone and in combination with tobramycin, at simulated representative lung fluid pharmacokinetics, against the free-floating (planktonic) and biofilm states of two hypermutable P. aeruginosa epidemic strains (LES-1 and CC274) from adolescents with cystic fibrosis. Regimens were intravenous ceftolozane/tazobactam 4.5 g/day continuous infusion, inhaled tobramycin 300 mg 12-hourly, intravenous tobramycin 10 mg/kg 24-hourly, and both ceftolozane/tazobactam-tobramycin combinations. The isolates were susceptible to both antibiotics. Total and less-susceptible free-floating and biofilm bacteria were quantified over 120-168 h. Ceftolozane/tazobactam resistance mechanisms were investigated by whole genome sequencing. Mechanism-based modelling of the bacterial viable counts was performed. Monotherapies of ceftolozane/tazobactam and tobramycin did not sufficiently suppress emergence of less-susceptible subpopulations, although inhaled tobramycin was more effective than intravenous tobramycin. Ceftolozane/tazobactam resistance development was associated with classical (AmpC overexpression plus structural modification) and novel (CpxR mutations) mechanisms depending on the strain. Against both isolates, the combination regimens demonstrated synergy and completely suppressed emergence of ceftolozane/tazobactam and tobramycin less-susceptible free-floating and biofilm bacterial subpopulations. Mechanism-based modelling incorporating subpopulation and mechanistic synergy well described the antibacterial effects of all regimens against free-floating and biofilm bacterial states. These findings support the further investigation of ceftolozane/tazobactam in combination with tobramycin against biofilm-associated P. aeruginosa infections in adolescents with cystic fibrosis.}, } @article {pmid37315462, year = {2023}, author = {Hu, X and Pan, Y and Zhao, S and Zhang, F and Li, F and Li, Z and Li, H and Li, Y and Lu, J and Yang, X and Bao, M}, title = {A step closer to real practice: Integrated tandem photocatalysis-biofilm process towards degradation of crude oil.}, journal = {Journal of environmental management}, volume = {342}, number = {}, pages = {118357}, doi = {10.1016/j.jenvman.2023.118357}, pmid = {37315462}, issn = {1095-8630}, mesh = {*Petroleum ; Bismuth ; Biodegradation, Environmental ; Biofilms ; }, abstract = {Intimately coupled photocatalysis and biodegradation (ICPB) systems represent a promising wastewater treatment technology. The implementation of ICPB systems for oil spill treatment is a pressing concern. In this study, we developed an ICPB system comprising BiOBr/modified g-C3N4 (M-CN) and biofilms for the treatment of oil spills. The results demonstrate that the ICPB system achieved the rapid degradation of crude oil, outperforming the single photocatalysis and biodegradation methods by degrading 89.08 ± 5.36% within 48 h. The combination of BiOBr and M-CN formed a Z-scheme heterojunction structure, enhancing the redox capacity. The interaction between the holes (h[+]) and the negative charge on the biofilm surface promoted the separation of electrons (e[-]) and h[+], thereby accelerating the degradation process of crude oil. Moreover, ICPB system maintained an excellent degradation ratio after three cycles and its biofilms progressively adapted to the adverse effects of crude oil and light. The microbial community structure remained stable throughout the degradation of crude oil, with Acinetobacter and Sphingobium identified as the dominant genera in biofilms. The proliferation of the Acinetobacter genus appeared to be the main factor contributing to the promotion of crude oil degradation. Our work demonstrates that the integrated tandem strategies perhaps represent a feasible pathway toward practical crude oil degradation.}, } @article {pmid37315081, year = {2023}, author = {Hills, OJ and Poskrobko, Z and Scott, AJ and Smith, J and Chappell, HF}, title = {A DFT study of the gallium ion-binding capacity of mature Pseudomonas aeruginosa biofilm extracellular polysaccharide.}, journal = {PloS one}, volume = {18}, number = {6}, pages = {e0287191}, pmid = {37315081}, issn = {1932-6203}, mesh = {Humans ; Pseudomonas aeruginosa ; Calcium ; Siderophores/pharmacology ; Polysaccharides ; Biofilms ; *Cystic Fibrosis ; *Gallium/pharmacology ; }, abstract = {Intravenous gallium therapy is a non-antibiotic approach to limit Pseudomonas aeruginosa biofilm proliferation, by outcompeting iron for siderophore binding. Gallium therapy represents a viable therapeutic strategy for cystic fibrosis (CF) patients harbouring mucoid P. aeruginosa biofilm lung infections. Siderophore deficient P. aeruginosa isolates still demonstrate a hindered biofilm proliferation when exposed to gallium but it is currently unknown whether exogenous gallium has any disruptive influence on the exopolysaccharide (EPS), the major mucoid P. aeruginosa CF lung biofilm matrix component. To that end, Density-Functional Theory (DFT) was deployed to assess whether gallium (Ga3+) could be substituted into the mature mucoid EPS scaffold in preference of calcium (Ca2+)-the native EPS cross-linking ion. Removal of the stable, bound native calcium ions offers a large enthalpic barrier to the substitution and the mature EPS fails to accommodate exogenous gallium. This suggests that gallium, perhaps, is utilising a novel, possibly unknown, ferric uptake system to gain entry to siderophore deficient cells.}, } @article {pmid37315001, year = {2023}, author = {Sadanandan, B and Vijayalakshmi, V and Ashrit, P and Babu, UV and Sharath Kumar, LM and Sampath, V and Shetty, K and Joglekar, AP and Awaknavar, R}, title = {Aqueous spice extracts as alternative antimycotics to control highly drug resistant extensive biofilm forming clinical isolates of Candida albicans.}, journal = {PloS one}, volume = {18}, number = {6}, pages = {e0281035}, pmid = {37315001}, issn = {1932-6203}, mesh = {Agar ; Candida albicans ; Spices ; *Garlic ; Antioxidants ; Biofilms ; *Biological Products ; }, abstract = {Candida albicans form biofilm by associating with biotic and abiotic surfaces. Biofilm formation by C. albicans is relevant and significant as the organisms residing within, gain resistance to conventional antimycotics and are therefore difficult to treat. This study targeted the potential of spice-based antimycotics to control C. albicans biofilms. Ten clinical isolates of C. albicans along with a standard culture MTCC-3017 (ATCC-90028) were screened for their biofilm-forming ability. C. albicans M-207 and C. albicans S-470 were identified as high biofilm formers by point inoculation on Trypticase Soy Agar (TSA) medium as they formed a lawn within 16 h and exhibited resistance to fluconazole and caspofungin at 25 mcg and 8 mcg respectively. Aqueous and organic spice extracts were screened for their antimycotic activity against C. albicans M-207 and S-470 by agar and disc diffusion and a Zone of Inhibition was observed. Minimal Inhibitory Concentration was determined based on growth absorbance and cell viability measurements. The whole aqueous extract of garlic inhibited biofilms of C. albicans M-207, whereas whole aqueous extracts of garlic, clove, and Indian gooseberry were effective in controlling C. albicans S-470 biofilm within 12 h of incubation. The presence of allicin, ellagic acid, and gallic acid as dominant compounds in the aqueous extracts of garlic, clove, and Indian gooseberry respectively was determined by High-Performance Thin Layer Chromatography and Liquid Chromatography-Mass Spectrometry. The morphology of C. albicans biofilm at different growth periods was also determined through bright field microscopy, phase contrast microscopy, and fluorescence microscopy. The results of this study indicated that the alternate approach in controlling high biofilm-forming, multi-drug resistant clinical isolates of C. albicans M-207 and S-470 using whole aqueous extracts of garlic, clove, and Indian gooseberry is a safe, potential, and cost-effective one that can benefit the health care needs with additional effective therapeutics to treat biofilm infections.}, } @article {pmid37314876, year = {2023}, author = {Yuan, L and Straub, H and Shishaeva, L and Ren, Q}, title = {Microfluidics for Biofilm Studies.}, journal = {Annual review of analytical chemistry (Palo Alto, Calif.)}, volume = {16}, number = {1}, pages = {139-159}, doi = {10.1146/annurev-anchem-091522-103827}, pmid = {37314876}, issn = {1936-1335}, mesh = {*Microfluidics ; *Biofilms ; Bacterial Adhesion ; Cues ; Extracellular Matrix ; }, abstract = {Biofilms are multicellular communities held together by a self-produced extracellular matrix and exhibit a set of properties that distinguish them from free-living bacteria. Biofilms are exposed to a variety of mechanical and chemical cues resulting from fluid motion and mass transport. Microfluidics provides the precise control of hydrodynamic and physicochemical microenvironments to study biofilms in general. In this review, we summarize the recent progress made in microfluidics-based biofilm research, including understanding the mechanism of bacterial adhesion and biofilm development, assessment of antifouling and antimicrobial properties, development of advanced in vitro infection models, and advancement in methods to characterize biofilms. Finally, we provide a perspective on the future direction of microfluidics-assisted biofilm research.}, } @article {pmid37314356, year = {2023}, author = {Deng, X and Xu, H and Li, D and Chen, J and Yu, Z and Deng, Q and Li, P and Zheng, J and Zhang, H}, title = {Mechanisms of Rapid Bactericidal and Anti-Biofilm Alpha-Mangostin In Vitro Activity against Staphylococcus aureus.}, journal = {Polish journal of microbiology}, volume = {72}, number = {2}, pages = {199-208}, pmid = {37314356}, issn = {2544-4646}, mesh = {Humans ; *Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; *Staphylococcal Infections ; Vancomycin ; Membrane Proteins ; Plankton ; }, abstract = {Alpha-mangostin (α-mangostin) was discovered as a potent natural product against Gram-positive bacteria, whereas the underlying molecular mechanisms are still unclear. This study indicated that α-mangostin (at 4 × MIC) rapidly killed Staphylococcus aureus planktonic cells more effectively (at least 2-log10 CFU/ml) than daptomycin, vancomycin and linezolid at 1 and 3 h in the time-killing test. Interestingly, this study also found that a high concentration of α-mangostin (≥4×MIC) significantly reduced established biofilms of S. aureus. There were 58 single nucleotide polymorphisms (SNPs) in α-mangostin nonsensitive S. aureus isolates by whole-genome sequencing, of which 35 SNPs were located on both sides of the sarT gene and 10 SNPs in the sarT gene. A total of 147 proteins with a different abundance were determined by proteomics analysis, of which 91 proteins increased, whereas 56 proteins decreased. The abundance of regulatory proteins SarX and SarZ increased. In contrast, the abundance of SarT and IcaB was significantly reduced (they belonged to SarA family and ica system, associated with the biofilm formation of S. aureus). The abundance of cell membrane proteins VraF and DltC was augmented, but the abundance of cell membrane protein UgtP remarkably decreased. Propidium iodide and DiBaC4(3) staining assay revealed that the fluorescence intensities of DNA and the cell membrane were elevated in the α-mangostin treated S. aureus isolates. In conclusion, this study reveals that α-mangostin was effective against S. aureus planktonic cells by targeting cell membranes. The anti-biofilm effect of α-mangostin may be through inhibiting the function of SarT and IcaB.}, } @article {pmid37313153, year = {2023}, author = {Barabadi, H and Mobaraki, K and Jounaki, K and Sadeghian-Abadi, S and Vahidi, H and Jahani, R and Noqani, H and Hosseini, O and Ashouri, F and Amidi, S}, title = {Exploring the biological application of Penicillium fimorum-derived silver nanoparticles: In vitro physicochemical, antifungal, biofilm inhibitory, antioxidant, anticoagulant, and thrombolytic performance.}, journal = {Heliyon}, volume = {9}, number = {6}, pages = {e16853}, pmid = {37313153}, issn = {2405-8440}, abstract = {This study showed the anti-candida, biofilm inhibitory, antioxidant, anticoagulant, and thrombolytic properties of biogenic silver nanoparticles (AgNPs) fabricated by using the supernatant of Penicillium fimorum (GenBank accession number OQ568180) isolated from soil. The biogenic AgNPs were characterized by using different analytical techniques. A sharp surface plasmon resonance (SPR) peak of the colloidal AgNPs at 429.5 nm in the UV-vis spectrum confirmed the fabrication of nanosized silver particles. The broth microdilution assay confirmed the anti-candida properties of AgNPs with a minimum inhibitory concentration (MIC) of 4 μg mL[-1]. In the next step, the protein and DNA leakage assays as well as reactive oxygen species (ROS) assay were performed to evaluate the possible anti-candida mechanisms of AgNPs representing an increase in the total protein and DNA of supernatant along with a climb-up in ROS levels in AgNPs-treated samples. Flow cytometry also confirmed a dose-dependent cell death in the AgNPs-treated samples. Further studies also confirmed the biofilm inhibitory performance of AgNPs against Candia albicans. The AgNPs at the concentrations of MIC and 4*MIC inhibited 79.68 ± 14.38% and 83.57 ± 3.41% of biofilm formation in C. albicans, respectively. Moreover, this study showed that the intrinsic pathway may play a significant role in the anticoagulant properties of AgNPs. In addition, the AgNPs at the concentration of 500 μg mL[-1], represented 49.27%, and 73.96 ± 2.59% thrombolytic and DPPH radical scavenging potential, respectively. Promising biological performance of AgNPs suggests these nanomaterials as a good candidate for biomedical and pharmaceutical applications.}, } @article {pmid37310652, year = {2023}, author = {Kulshrestha, A and Gupta, P}, title = {Combating polymicrobial biofilm: recent approaches.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {37310652}, issn = {1874-9356}, abstract = {The polymicrobial biofilm (PMBF) is formed when microbes from multiple species co-aggregate into an envelope made of extra polymeric substances (EPS) that keep the microbes safe from external stresses. The formation of PMBF has been linked to a variety of human infections, including cystic fibrosis, dental caries, urinary tract infections, etc. Multiple microbial species co-aggregation during an infection results in a recalcitrant biofilm formation, which is a seriously threatening phenomenon. It is challenging to treat polymicrobial biofilms since they contain multiple microbes which show drug resistance to various antibiotics/antifungals. The present study discusses various approaches by which an antibiofilm compound works. Depending on their mode of action, antibiofilm compounds can block the adhesion of cells to one another, modify membranes/walls, or disrupt quorum-sensing systems.}, } @article {pmid37310410, year = {2023}, author = {Wu, H and Wei, M and Hu, S and Cheng, P and Shi, S and Xia, F and Xu, L and Yin, L and Liang, G and Li, F and Ling, D}, title = {A Photomodulable Bacteriophage-Spike Nanozyme Enables Dually Enhanced Biofilm Penetration and Bacterial Capture for Photothermal-Boosted Catalytic Therapy of MRSA Infections.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {}, number = {}, pages = {e2301694}, doi = {10.1002/advs.202301694}, pmid = {37310410}, issn = {2198-3844}, support = {2022YFB3203801//National Key Research and Development Program of China/ ; 2022YFB3203804//National Key Research and Development Program of China/ ; 2022YFB3203800//National Key Research and Development Program of China/ ; 32071374//National Natural Science Foundation of China/ ; 32201161//National Natural Science Foundation of China/ ; 21XD1422100//Program of Shanghai Academic Research Leader under the Science and Technology Innovation/ ; 22TS1400700//Explorer Program of Science and Technology Commission of Shanghai Municipality/ ; LR22C100001//Zhejiang Provincial Natural Science Foundation of China/ ; LQ21H300004//Zhejiang Provincial Natural Science Foundation of China/ ; GF22H168862//Zhejiang Provincial Natural Science Foundation of China/ ; SHSMU-ZDCX20210900//Innovative Research Team of High-Level Local Universities in Shanghai/ ; 00004F1RCYJ2209//Hangzhou Medical College Qiuzhen Talent Project/ ; KYZD202205//Basic Scientific Research Funds of Department of Education of Zhejiang Province/ ; 2021438429//Health Bureau of Zhejiang Province/General Program/ ; 2023ZF122//Zhejiang Traditional Chinese Medicine Science and Technology Program/ ; 2021C03041//Zhejiang Provincial Key Scientific Project/ ; JCTD-2020-08//CAS Interdisciplinary Innovation Team/ ; }, abstract = {Nanozymes, featuring intrinsic biocatalytic effects and broad-spectrum antimicrobial properties, are emerging as a novel antibiotic class. However, prevailing bactericidal nanozymes face a challenging dilemma between biofilm penetration and bacterial capture capacity, significantly impeding their antibacterial efficacy. Here, this work introduces a photomodulable bactericidal nanozyme (ICG@hMnOx), composed of a hollow virus-spiky MnOx nanozyme integrated with indocyanine green, for dually enhanced biofilm penetration and bacterial capture for photothermal-boosted catalytic therapy of bacterial infections. ICG@hMnOx demonstrates an exceptional capability to deeply penetrate biofilms, owing to its pronounced photothermal effect that disrupts the compact structure of biofilms. Simultaneously, the virus-spiky surface significantly enhances the bacterial capture capacity of ICG@hMnOx . This surface acts as a membrane-anchored generator of reactive oxygen species and a glutathione scavenger, facilitating localized photothermal-boosted catalytic bacterial disinfection. Effective treatment of methicillin-resistant Staphylococcus aureus-associated biofilm infections is achieved using ICG@hMnOx , offering an appealing strategy to overcome the longstanding trade-off between biofilm penetration and bacterial capture capacity in antibacterial nanozymes. This work presents a significant advancement in the development of nanozyme-based therapies for combating biofilm-related bacterial infections.}, } @article {pmid37310227, year = {2023}, author = {Cassin, EK and Araujo-Hernandez, SA and Baughn, DS and Londono, MC and Rodriguez, DQ and Al-Otaibi, NS and Picard, A and Bergeron, JRC and Tseng, BS}, title = {OprF Impacts Pseudomonas aeruginosa Biofilm Matrix eDNA Levels in a Nutrient-Dependent Manner.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0008023}, doi = {10.1128/jb.00080-23}, pmid = {37310227}, issn = {1098-5530}, abstract = {The biofilm matrix is composed of exopolysaccharides, eDNA, membrane vesicles, and proteins. While proteomic analyses have identified numerous matrix proteins, their functions in the biofilm remain understudied compared to the other biofilm components. In the Pseudomonas aeruginosa biofilm, several studies have identified OprF as an abundant matrix protein and, more specifically, as a component of biofilm membrane vesicles. OprF is a major outer membrane porin of P. aeruginosa cells. However, current data describing the effects of OprF in the P. aeruginosa biofilm are limited. Here, we identify a nutrient-dependent effect of OprF in static biofilms, whereby ΔoprF cells form significantly less biofilm than wild type when grown in media containing glucose or low sodium chloride concentrations. Interestingly, this biofilm defect occurs during late static biofilm formation and is not dependent on the production of PQS, which is responsible for outer membrane vesicle production. Furthermore, while biofilms lacking OprF contain approximately 60% less total biomass than those of wild type, the number of cells in these two biofilms is equivalent. We demonstrate that P. aeruginosa ΔoprF biofilms with reduced biofilm biomass contain less eDNA than wild-type biofilms. These results suggest that the nutrient-dependent effect of OprF is involved in the maintenance of P. aeruginosa biofilms by retaining eDNA in the matrix. IMPORTANCE Many pathogens form biofilms, which are bacterial communities encased in an extracellular matrix that protects them against antibacterial treatments. The roles of several matrix components of the opportunistic pathogen Pseudomonas aeruginosa have been characterized. However, the effects of P. aeruginosa matrix proteins remain understudied and are untapped potential targets for antibiofilm treatments. Here, we describe a conditional effect of the abundant matrix protein OprF on late-stage P. aeruginosa biofilms. A ΔoprF strain formed significantly less biofilm in low sodium chloride or with glucose. Interestingly, the defective ΔoprF biofilms did not exhibit fewer resident cells but contained significantly less extracellular DNA (eDNA) than wild type. These results suggest that OprF is involved in matrix eDNA retention in biofilms.}, } @article {pmid37310210, year = {2023}, author = {Xu, ZS and Zhu, T and Wang, Z and Yang, X and Gänzle, MG}, title = {Socializing at the Air-Liquid Interface: a Functional Genomic Analysis on Biofilm-Related Genes during Pellicle Formation by Escherichia coli and Its Interaction with Aeromonas australiensis.}, journal = {Applied and environmental microbiology}, volume = {}, number = {}, pages = {e0045623}, doi = {10.1128/aem.00456-23}, pmid = {37310210}, issn = {1098-5336}, abstract = {Pellicles are biofilms that form at the air-liquid interface. We demonstrated that specific strains of Escherichia coli formed pellicles in single cultures when cocultured with Carnobacterium maltaromaticum and E. coli O157:H7 but not with Aeromonas australiensis. Therefore, a combination of comparative genomic, mutational, and transcriptome analyses were applied to identify the unique genes in pellicle formation and investigate gene regulation under different growth phases. Here, we report that pellicle-forming strains do not harbor unique genes relative to non-pellicle-forming strains; however, the expression level of biofilm-related genes differed, especially for the genes encoding curli. Further, the regulatory region of curli biosynthesis is phylogenetically different among pellicle- and non-pellicle-forming strains. The disruption on modified cellulose and regulatory region of curli biosynthesis abolished pellicle formation in strains of E. coli. Besides, the addition of quorum sensing molecules (C4-homoserine lactones [C4-HSL]), synthesized by Aeromonas species, to pellicle formers abolished pellicle formation and implied a role of quorum sensing on pellicle formation. The deletion of autoinducer receptor sdiA in E. coli did not restore pellicle formation when cocultured with A. australiensis but modulated expression level of genes for curli and cellulose biosynthesis, resulting in a thinner layer of pellicle. Taken together, this study identified genetic determinants for pellicle formation and characterized the switching between pellicle to surface-associated biofilm in a dual-species environment, facilitating better understanding of the mechanisms for pellicle formation in E. coli and related organisms. IMPORTANCE To date, most attention has focused on biofilm formation on solid surfaces. By comparison, the knowledge on pellicle formation at the air-liquid interface is more limited and few studies document how bacteria decide on whether to form biofilms on solid surfaces or pellicles at the air-liquid interface to the surface-associated biofilms at the bottom. In this report, we characterized the regulation of biofilm-related genes during pellicle formation and document that interspecies communication via quorum sensing contributes to regulating the switch from pellicle to surface-associated biofilm. The discoveries expand the current view of regulatory cascades associated with pellicle formation.}, } @article {pmid37309029, year = {2023}, author = {Khani, N and Soleimani, RA and Chadorshabi, S and Moutab, BP and Milani, PG and Rad, AH}, title = {Postbiotics as candidates in biofilm inhibition in food industries.}, journal = {Letters in applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/lambio/ovad069}, pmid = {37309029}, issn = {1472-765X}, abstract = {Food-borne pathogen-related biofilms in food processing environments pose significant risks to human health. To ensure human and environmental safety, natural substances with anti-microbial properties and generally recognized as safe (GRAS) status are the future disinfectants of the food industry. The use of postbiotics in food products is gaining attention due to their many benefits. Postbiotics are soluble substances produced by probiotics or released after their lysis, such as bacteriocins, biosurfactants (BSs), and exopolysaccharides (EPS). Postbiotics have drawn attention because of their clear chemical structure, safety dose parameters, long shelf life, and the content of various signaling molecules, which may have anti-biofilm and antibacterial activities. The main mechanisms of postbiotics to combat biofilm contain suppression of twitching motility, disturbing quorum sensing (QS), and reduction of virulence factors. However, there are obstacles to using these compounds in the food matrix because some factors (temperature and pH) can limit the anti-biofilm impact of postbiotics. Therefore, by using encapsulation or application of these compounds in packaging films, the effect of interfering factors can be eliminated. This review summarizes the concept and safety of postbiotics, focusing on their antibiofilm effect, as well as discussing the encapsulation of postbiotics and their application in packaging films.}, } @article {pmid37308007, year = {2023}, author = {Murshid, S and Antonysamy, A and Dhakshinamoorthy, G and Jayaseelan, A and Pugazhendhi, A}, title = {A review on biofilm-based reactors for wastewater treatment: Recent advancements in biofilm carriers, kinetics, reactors, economics, and future perspectives.}, journal = {The Science of the total environment}, volume = {892}, number = {}, pages = {164796}, doi = {10.1016/j.scitotenv.2023.164796}, pmid = {37308007}, issn = {1879-1026}, abstract = {Industrialization plays an important role in the growth of a nation. But it is also added to the deteriorating condition of our ecosystem. Pollution, be it aquatic, terrestrial, or airborne, has affected our environment drastically and the surge of industries and growing population plays a major role in it. Innumerable basic and advanced techniques degrade the contaminants in wastewater. Most of these techniques are efficient but have several drawbacks too. The biological technique is one such viable approach in which there are no eminent downsides. This article presents a brief investigation of the biological treatment of wastewater, namely biofilm technology. Recently biofilm treatment technology has garnered a lot of attention due to its efficiency, inexpensiveness, and ease of incorporation into various conventional treatment techniques. A succinct analysis is provided about the mechanism of biofilm formation and its application in various systems in fixed, suspended, or submerged conditions. Details of the application of biofilm technology in lab-scale and pilot-scale treatment of industrial effluents are also discussed. This study is crucial to understand the competency of biofilms and to utilize the idea for further development of the technology for better management of wastewater. Pollutants such as BOD, COD can be removed up to 98 % with the help of Biofilm reactor technologies, making it one of the most efficient systems for wastewater treatment.}, } @article {pmid37307854, year = {2023}, author = {Yang, JL and Yuan, HQ and Fu, JH and Luo, X and Bao, GM}, title = {Facile one-precursor and one-pot synthesis of Girard's reagent T-based carbon dots for bacteria-resistant and anti-biofilm applications.}, journal = {Biomedical materials (Bristol, England)}, volume = {18}, number = {4}, pages = {}, doi = {10.1088/1748-605X/acddc3}, pmid = {37307854}, issn = {1748-605X}, mesh = {*Staphylococcus aureus ; *Carbon ; Escherichia coli ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Bacteria ; Microbial Sensitivity Tests ; }, abstract = {Based on the promising development of carbon dots in antibacterial applications, Girard's reagent T-based carbon dots (GRT-CDs) with a mean size of 2.41 nm and excellent antibacterial performance were synthesized through a one-step method. The minimum inhibitory concentration ofGRT-CDswas 200 μg ml[-1]for bothEscherichia coli (E. coli)andStaphylococcus aureus (S. aureus). The bacterial growth curves showed that the inhibitory effect ofGRT-CDson bacterial multiplication was strongly concentration-dependent. The bactericidal effect ofGRT-CDswas further demonstrated by the large differences in bacterial fluorescence staining plots. Zeta potential measurements and scanning electron microscope images indicated thatGRT-CDsformed complexes with bacteria, which affected the normal physiological activities of bacteria, causing their rupture and death. In addition,GRT-CDsefficiently inhibited biofilm formation and removed mature biofilms. Furthermore,GRT-CDsalso exhibited a remarkable inhibitory activity on MRSA. Cytotoxicity experiments showed thatGRT-CDshad good cytocompatibility and even promoted cell proliferation at low concentrations. Therefore, theGRT-CDsobtained from a one-precursor and one-pot synthesis show good prospects for antibacterial applications.}, } @article {pmid37307459, year = {2023}, author = {Wong, JPH and Fischer-Stettler, M and Zeeman, SC and Battin, TJ and Persat, A}, title = {Fluid flow structures gut microbiota biofilm communities by distributing public goods.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {25}, pages = {e2217577120}, doi = {10.1073/pnas.2217577120}, pmid = {37307459}, issn = {1091-6490}, mesh = {Humans ; *Gastrointestinal Microbiome ; Dextrans ; *Microbiota ; Bacteroides fragilis ; *Bacteroides thetaiotaomicron ; Biofilms ; }, abstract = {Bacterial gut commensals experience a biologically and physically complex mucosal environment. While many chemical factors mediate the composition and structure of these microbial communities, less is known about the role of mechanics. Here, we demonstrate that fluid flow impacts the spatial organization and composition of gut biofilm communities by shaping how different species interact metabolically. We first demonstrate that a model community composed of Bacteroides thetaiotaomicron (Bt) and Bacteroides fragilis (Bf), two representative human commensals, can form robust biofilms in flow. We identified dextran as a polysaccharide readily metabolized by Bt but not Bf, but whose fermentation generates a public good enabling Bf growth. By combining simulations with experiments, we demonstrate that in flow, Bt biofilms share dextran metabolic by-products, promoting Bf biofilm formation. By transporting this public good, flow structures the spatial organization of the community, positioning the Bf population downstream from Bt. We show that sufficiently strong flows abolish Bf biofilm formation by limiting the effective public good concentration at the surface. Physical factors such as flow may therefore contribute to the composition of intestinal microbial communities, potentially impacting host health.}, } @article {pmid37307133, year = {2023}, author = {Li, YH and Zhang, SX and Yang, Y and Wang, TY and Zheng, JX}, title = {Analyzing the Activity of Micafungin Combined with Tobramycin Against Pseudomonas Aeruginosa Biofilm.}, journal = {Clinical laboratory}, volume = {69}, number = {6}, pages = {}, doi = {10.7754/Clin.Lab.2022.220841}, pmid = {37307133}, issn = {1433-6510}, mesh = {Humans ; *Tobramycin ; *Pseudomonas aeruginosa ; Micafungin ; Anti-Bacterial Agents ; Biofilms ; }, abstract = {BACKGROUND: This study assessed the potential effect of combining micafungin and tobramycin in vitro against biofilms of clinical Pseudomonas aeruginosa isolates.

METHODS: Nine biofilm-positive clinical isolates of P. aeruginosa were used in this study. The minimum inhibitory concentrations (MICs) of micafungin and tobramycin for planktonic bacteria were determined using the agar dilution method. The planktonic bacterial growth curve was plotted for micafungin treatment. Biofilms of these nine strains were treated with different concentrations of micafungin and combined with tobramycin in microtiter plates. Biofilm biomass was detected by crystal violet staining and spectrophotometry. Phenotypic reduction in biofilm formation and the eradication of mature biofilm were significant based on average optical density (p < 0.05). The kinetics of micafungin combined with tobramycin to eradicate mature biofilms was investigated in vitro using the time-kill method.

RESULTS: Micafungin exhibited no antibacterial effect on P. aeruginosa, and tobramycin minimum inhibitory concentrations (MICs) did not change in the presence of micafungin. Micafungin alone inhibited biofilm formation and eradicated established biofilms of all isolates in a dose-dependent manner, but the required minimum concentration varied. An increase in micafungin concentration resulted in an observed inhibition rate of 64.9% - 72.3% and achieved an eradication rate of 59.2% - 64.5%. Its combination with tobramycin exhibited synergistic effects, including inhibiting the biofilm formation of PA02, PA05, PA23, PA24, and PA52 isolates above 1/4 × MIC or 1/2 × MIC and eradicating mature biofilms of PA02, PA04, PA23, PA24, and PA52 above 32 × MIC, 2 × MIC, 16 × MIC, 32 × MIC, and 1 × MIC, respectively. Micafungin addition could eradicate biofilm-embedded bacterial cells more rapidly; at 32 mg/L, the biofilm eradication time lowered from 24 hours to 12 hours for the inoculum groups with 106 CFU/mL, and from 12 hours to 8 hours for 105 CFU/mL. Whereas at 128 mg/L, the time was lowered from 12 hours to 8 hours for the inoculum groups with 106 CFU/mL, and from 8 hours to 4 hours for 105 CFU/mL.

CONCLUSIONS: Micafungin showed good anti-biofilm activity at low concentrations. The combination of micafungin with tobramycin displayed a synergistic effect in controlling P. aeruginosa biofilm.}, } @article {pmid37306594, year = {2023}, author = {Dial, CN and Fung, BL and Visick, KL}, title = {Genetic Analysis Reveals a Requirement for the Hybrid Sensor Kinase RscS in para-Aminobenzoic Acid/Calcium-Induced Biofilm Formation by Vibrio fischeri.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0007523}, doi = {10.1128/jb.00075-23}, pmid = {37306594}, issn = {1098-5530}, abstract = {The marine bacterium Vibrio fischeri initiates symbiotic colonization of its squid host, Euprymna scolopes, by forming and dispersing from a biofilm dependent on the symbiosis polysaccharide locus (syp). Historically, genetic manipulation of V. fischeri was needed to visualize syp-dependent biofilm formation in vitro, but recently, we discovered that the combination of two small molecules, para-aminobenzoic acid (pABA) and calcium, was sufficient to induce wild-type strain ES114 to form biofilms. Here, we determined that these syp-dependent biofilms were reliant on the positive syp regulator RscS, since the loss of this sensor kinase abrogated biofilm formation and syp transcription. These results were of particular note because loss of RscS, a key colonization factor, exerts little to no effect on biofilm formation under other genetic and medium conditions. The biofilm defect could be complemented by wild-type RscS and by an RscS chimera that contains the N-terminal domains of RscS fused to the C-terminal HPT domain of SypF, the downstream sensor kinase. It could not be complemented by derivatives that lacked the periplasmic sensory domain or contained a mutation in the conserved site of phosphorylation, H412, suggesting that these cues promote signaling through RscS. Lastly, pABA and/or calcium was able to induce biofilm formation when rscS was introduced into a heterologous system. Taken together, these data suggest that RscS is responsible for recognizing pABA and calcium, or downstream consequences of those cues, to induce biofilm formation. This study thus provides insight into signals and regulators that promote biofilm formation by V. fischeri. IMPORTANCE Bacterial biofilms are common in a variety of environments. Infectious biofilms formed in the human body are notoriously hard to treat due to a biofilm's intrinsic resistance to antibiotics. Bacteria must integrate signals from the environment to build and sustain a biofilm and often use sensor kinases that sense an external signal, which triggers a signaling cascade to elicit a response. However, identifying the signals that kinases sense remains a challenging area of investigation. Here, we determine that a hybrid sensor kinase, RscS, is crucial for Vibrio fischeri to recognize para-aminobenzoic acid and calcium as cues to induce biofilm formation. This study thus advances our understanding of the signal transduction pathways leading to biofilm formation.}, } @article {pmid37305623, year = {2023}, author = {Leong, JY and Ancira, J and Bulafka, J and Shenot, PJ and Das, AK and Chung, PH}, title = {Characterizing the biofilm of artificial urinary sphincters (AUS).}, journal = {Translational andrology and urology}, volume = {12}, number = {5}, pages = {866-873}, pmid = {37305623}, issn = {2223-4691}, abstract = {BACKGROUND: There is a paucity of data regarding the bacterial colonization on artificial urinary sphincter (AUS) devices following revision surgery. We aim to evaluate the microbial compositions of explanted AUS devices identified on standard culture at our institution.

METHODS: Twenty-three AUS devices explanted were included in this study. During revision surgery, aerobic and anaerobic culture swabs are taken from the implant, capsule, fluid surrounding the device, and biofilm, if present. Culture specimens are sent to the hospital laboratory for routine culture evaluation immediately upon case completion. Differences in number of microorganism species detected across samples (richness) against demographic variables were determined through backwards selection of all variables using analysis of variance (ANOVA). We assessed the prevalence (how many times each species occurred) of microbial culture species. Statistical analyses were performed using the statistical package in R (version 4.2.1).

RESULTS: Cultures reported positive results in 20 (87%) cases. Coagulase-negative staphylococci were the most commonly identified bacteria among explanted AUS devices (n=16, 80%). Among two of the four infected/eroded implants, more virulent organisms such as Escherichia coli and fungal species such as Candida albicans were identified. The mean number of species identified amongst culture positive devices was 2.15±0.49. The number of unique bacteria identified per sample was not significantly associated with demographic variables including race, ethnicity, age at revision, smoking history, duration of implantation, etiology for explantation, and concomitant medical comorbidities.

CONCLUSIONS: The majority of AUS devices removed for non-infectious reasons harbor organisms on traditional culture at the time of explantation. The most commonly identified bacteria in this setting is coagulase-negative staphylococci, which may be a result of bacterial colonization introduced at the time of implant. Conversely, infected implants may harbor microorganisms with higher virulence including fungal elements. Bacterial colonization or biofilm formation on implants may not necessarily equate to clinically infected devices. Future studies with more sophisticated technology, such as next-generation sequencing or extended cultures, may evaluate microbial compositions of biofilm at a more granular level to understand its role in device infections.}, } @article {pmid37303803, year = {2023}, author = {Wei, D and Zhang, X and Li, C and Ma, Z and Zhao, M and Wei, L}, title = {Efficiency and microbial community characteristics of strong alkali ASP flooding produced water treated by composite biofilm system.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1166907}, pmid = {37303803}, issn = {1664-302X}, abstract = {Strong alkali alkali-surfactant-polymer (ASP) flooding produced water is a by-product of oil recovery, and it is a stable system composed of petroleum, polyacrylamide, surfactant, and inorganic salts. Efficient, green, and safe ASP produced water treatment technology is essential for oilfield exploitation and environmental protection. In this study, an anaerobic/anoxic/moving bed biofilm reactor with a microfiltration membrane was established and assessed for the real strong alkali ASP flooding produced water (pH 10.1-10.4) treatment. The results show that the average removal rates of COD, petroleum, suspended solids, polymers and surfactants in this process are 57, 99, 66, 40, and 44%, respectively. GC-MS results show that most of the organic compounds such as alkanes and olefins in the strong alkali ASP produced water are degraded. Microfiltration membrane can significantly improve the efficiency and stability of sewage treatment system. Paracoccus (AN), Synergistaceae (ANO) and Trichococcus (MBBR) are the main microorganisms involved in the degradation of pollutants. This study reveals the potential and adaptability of composite biofilm system in treating the produced water of strong alkali ASP produced water.}, } @article {pmid37303747, year = {2023}, author = {Weaver, JE}, title = {Quantifying drift-selection balance using an agent-based biofilm model of identical heterotrophs under low-nutrient conditions.}, journal = {Interface focus}, volume = {13}, number = {4}, pages = {20230010}, pmid = {37303747}, issn = {2042-8898}, abstract = {Both deterministic and stochastic forces shape biofilm communities, but the balance between those forces is variable. Quantifying the balance is both desirable and challenging. For example, drift-driven failure, a stochastic force, can be thought of as an organism experiencing 'bad luck' and manipulating 'luck' as a factor in real-world systems is difficult. We used an agent-based model to manipulate luck by controlling seed cevalues governing random number generation. We determined which organism among identical competitors experienced the greatest drift-driven failure, gave it a deterministic growth advantage and re-ran the simulation with the same seed. This enabled quantifying the growth advantage required to overcome drift, e.g. a 50% chance to thrive may require a 10-20% improved growth rate. Further, we found that crowding intensity affected that balance. At moderate spacings, there were wide ranges where neither drift nor selection dominated. Those ranges shrank at extreme spacings; close and loose crowding, respectively, favoured drift and selection. We explain how these results may partially illuminate two conundrums: the fact that a stably operating wastewater treatment plant's microbial community can vary greatly over time and the difference between equivalent and total community size in neutral community assembly models.}, } @article {pmid37302278, year = {2023}, author = {Shao, H and Zhou, J and Lin, X and Zhou, Y and Xue, Y and Hong, W and Lin, X and Jia, X and Fan, Y}, title = {Bio-inspired peptide-conjugated liposomes for enhanced planktonic bacteria killing and biofilm eradication.}, journal = {Biomaterials}, volume = {300}, number = {}, pages = {122183}, doi = {10.1016/j.biomaterials.2023.122183}, pmid = {37302278}, issn = {1878-5905}, abstract = {Developing new antimicrobial agents has become an urgent task to address the increasing prevalence of multidrug-resistant pathogens and the emergence of biofilms. Cationic antimicrobial peptides (AMPs) have been regarded as promising candidates due to their unique non-specific membrane rupture mechanism. However, a series of problems with the peptides hindered their practical application due to their high toxicity and low bioactivity and stability. Here, inspired by broadening the application of cell-penetrating peptides (CPPs), we selected five different sequences of cationic peptides which are considered as both CPPs and AMPs, and developed a biomimetic strategy to construct cationic peptide-conjugated liposomes with the virus-like structure for both enhancements of antibacterial efficacy and biosafety. The correlation between available peptide density/peptide variety and antimicrobial capabilities was evaluated from quantitative perspectives. Computational simulation and experimental investigations assisted to identify the optimal peptide-conjugated liposomes and revealed that the designed system provides high charge density for enhanced anionic bacterial membrane binding capability without compromised cytotoxicity, being capable of enhanced antibacterial efficacy of bacteria/biofilm of clinically important pathogens. The bio-inspired design has shown enhanced therapeutic efficiency of peptides and may promote the development of next-generation antimicrobials.}, } @article {pmid37301614, year = {2023}, author = {Zhang, L and You, H and Chen, J and Huang, B and Cui, Y and Hossain, KB and Chen, Q and Cai, M and Qian, Q}, title = {Surface structures changes and biofilm communities development of degradable plastics during aging in coastal seawater.}, journal = {Marine pollution bulletin}, volume = {193}, number = {}, pages = {114996}, doi = {10.1016/j.marpolbul.2023.114996}, pmid = {37301614}, issn = {1879-3363}, abstract = {Biodegradable plastics (BPs) are a suitable alternative to conventional plastics. Still, their excessive or unplanned use may disrupt the abundance and community structure of the microbial population. To this end, a 58-day experiment in which biodegradable plastic objects, such as bags and boxes, were exposed to near-coastal seawater was conducted. They also assessed how they affected the diversity and organization of bacterial populations in seawater and on the surface of BPs products. It is evident that after the exposure time, both BP's bag and box products deteriorate in the ocean to varying degrees. The results of high-throughput sequencing of bacterial communities in seawater and those colonized on BPs products reveal significant differences in microbial community structures between seawater and BPs plastic samples. These suggest that the degradation of biodegradable plastics is shadowed by microorganisms and exposure time, while BP products influence the structural characteristics of microbial communities.}, } @article {pmid37301070, year = {2023}, author = {Vandana, and Das, S}, title = {Cell surface hydrophobicity and petroleum hydrocarbon degradation by biofilm-forming marine bacterium Pseudomonas furukawaii PPS-19 under different physicochemical stressors.}, journal = {Journal of hazardous materials}, volume = {457}, number = {}, pages = {131795}, doi = {10.1016/j.jhazmat.2023.131795}, pmid = {37301070}, issn = {1873-3336}, mesh = {*Petroleum/metabolism ; Hydrocarbons/metabolism ; Biodegradation, Environmental ; Biofilms ; Bacteria/metabolism ; Pyrenes ; Hydrophobic and Hydrophilic Interactions ; *Petroleum Pollution ; }, abstract = {Biofilm-forming marine bacterium Pseudomonas furukawaii PPS-19 showed strong hydrophobicity under different physicochemical stressors, such as pH and salinity. Strong aggregation of P. furukawaii PPS-19 was observed at hydrophobic interfaces of n-dodecane and crude oil, while uptake of pyrene resulted in blue fluorescence of the bacterium. Changes in biofilm microcolonies were observed under different physicochemical stressors with maximum biofilm thickness of 15.15 µm and 15.77 µm at pH 7% and 1% salinity, respectively. Relative expression analysis of alkB2 gene revealed the maximum expression in n-dodecane (10.5 fold) at pH 7 (1 fold) and 1% salinity (8.3 fold). During the degradation process, a significant drop in surface tension resulted in increased emulsification activity. P. furukawaii PPS-19 showed the respective n-dodecane and pyrene degradation of 94.3% and 81.5% at pH 7% and 94.5% and 83% at 1% salinity. A significant positive correlation was obtained between cell surface hydrophobicity (CSH), biofilm formation, and PHs degradation (P < 0.05) under all the physicochemical stressors, with the highest value at pH 7% and 1% salinity. Analysis of metabolites indicated that mono-terminal oxidation and multiple pathways were followed for n-dodecane and pyrene biodegradation, respectively. Thus, P. furukawaii PPS-19 is an efficient hydrocarbonoclastic bacterium that may be exploited for large-scale oil pollution abatement.}, } @article {pmid37300862, year = {2023}, author = {Rippon, M and Rogers, AA and Westgate, S and Ousey, K}, title = {Effectiveness of a polyhexamethylene biguanide-containing wound cleansing solution using experimental biofilm models.}, journal = {Journal of wound care}, volume = {32}, number = {6}, pages = {359-367}, doi = {10.12968/jowc.2023.32.6.359}, pmid = {37300862}, issn = {0969-0700}, mesh = {Humans ; *Anti-Infective Agents, Local/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology/therapeutic use ; Staphylococcus aureus ; *Disinfectants/pharmacology/therapeutic use ; Biofilms ; *Wound Infection/microbiology ; Pseudomonas aeruginosa ; }, abstract = {OBJECTIVE: Antiseptics are widely used in wound management to prevent or treat wound infections, and have been shown to have antibiofilm efficacy. The objective of this study was to assess the effectiveness of a polyhexamethylene biguanide (PHMB)-containing wound cleansing and irrigation solution on model biofilm of pathogens known to cause wound infections compared with a number of other antimicrobial wound cleansing and irrigation solutions.

METHOD: Staphylococcus aureus and Pseudomonas aeruginosa single-species biofilms were cultured using microtitre plate and Centers for Disease Control and Prevention (CDC) biofilm reactor methods. Following a 24-hour incubation period, the biofilms were rinsed to remove planktonic microorganisms and then challenged with wound cleansing and irrigation solutions. Following incubation of the biofilms with a variety of concentrations of the test solutions (50%, 75% or 100%) for 20, 30, 40, 50 or 60 minutes, remaining viable organisms from the treated biofilms were quantified.

RESULTS: The six antimicrobial wound cleansing and irrigation solutions used were all effective in eradicating Staphylococcus aureus biofilm bacteria in both test models. However, the results were more variable for the more tolerant Pseudomonas aeruginosa biofilm. Only one of the six solutions (sea salt and oxychlorite/NaOCl-containing solution) was able to eradicate Pseudomonas aeruginosa biofilm using the microtitre plate assay. Of the six solutions, three (a solution containing PHMB and poloxamer 188 surfactant, a solution containing hypochlorous acid (HOCl) and a solution containing NaOCl/HOCl) showed increasing levels of eradication of Pseudomonas aeruginosa biofilm microorganisms with increasing concentration and exposure time. Using the CDC biofilm reactor model, all six cleansing and irrigation solutions, except for the solution containing HOCl, were able to eradicate Pseudomonas aeruginosa biofilms such that no viable microorganisms were recovered.

CONCLUSION: This study demonstrated that a PHMB-containing wound cleansing and irrigation solution was as effective as other antimicrobial wound irrigation solutions for antibiofilm efficacy. Together with the low toxicity, good safety profile and absence of any reported acquisition of bacterial resistance to PHMB, the antibiofilm effectiveness data support the alignment of this cleansing and irrigation solution with antimicrobial stewardship (AMS) strategies.}, } @article {pmid37299186, year = {2023}, author = {Carezzano, ME and Paletti Rovey, MF and Cappellari, LDR and Gallarato, LA and Bogino, P and Oliva, MLM and Giordano, W}, title = {Biofilm-Forming Ability of Phytopathogenic Bacteria: A Review of its Involvement in Plant Stress.}, journal = {Plants (Basel, Switzerland)}, volume = {12}, number = {11}, pages = {}, pmid = {37299186}, issn = {2223-7747}, abstract = {Phytopathogenic bacteria not only affect crop yield and quality but also the environment. Understanding the mechanisms involved in their survival is essential to develop new strategies to control plant disease. One such mechanism is the formation of biofilms; i.e., microbial communities within a three-dimensional structure that offers adaptive advantages, such as protection against unfavorable environmental conditions. Biofilm-producing phytopathogenic bacteria are difficult to manage. They colonize the intercellular spaces and the vascular system of the host plants and cause a wide range of symptoms such as necrosis, wilting, leaf spots, blight, soft rot, and hyperplasia. This review summarizes up-to-date information about saline and drought stress in plants (abiotic stress) and then goes on to focus on the biotic stress produced by biofilm-forming phytopathogenic bacteria, which are responsible for serious disease in many crops. Their characteristics, pathogenesis, virulence factors, systems of cellular communication, and the molecules implicated in the regulation of these processes are all covered.}, } @article {pmid37298427, year = {2023}, author = {Simões, LC and Simões, M}, title = {Contribution to Understanding the Mechanisms Involved in Biofilm Formation, Tolerance and Control.}, journal = {International journal of molecular sciences}, volume = {24}, number = {11}, pages = {}, pmid = {37298427}, issn = {1422-0067}, support = {POCI-01-0247-FEDER-072237//Agencia de Inovacao/ ; }, mesh = {Humans ; Biofilms ; Staphylococcus aureus ; *Anti-Infective Agents/pharmacology ; Escherichia coli ; *Staphylococcal Infections ; Pseudomonas aeruginosa/genetics ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Biofilms constitute a protected mode of growth that allows the colonizing microbial cells to survive in hostile environments, even when an antimicrobial agent is present. The scientific community has come to understand many things about the growth dynamics and behavior of microbial biofilms. It is now accepted that biofilm formation is a multifactorial process that starts with the adhesion of individual cells and (auto-)coaggregates of cells to a surface. Then, attached cells grow, reproduce and secrete insoluble extracellular polymeric substances. As the biofilm matures, biofilm detachment and growth processes come into balance, such that the total amount of biomass on the surface remains approximately constant in time. The detached cells retain the phenotype of the biofilm cells, which facilitates the colonization of neighboring surfaces. The most common practice to eliminate unwanted biofilms is the application of antimicrobial agents. However, conventional antimicrobial agents often show inefficacy in the control of biofilms. Much remains to be understood in the biofilm formation process and in the development of effective strategies for biofilm prevention and control. The articles contained in this Special Issue deal with biofilms of some important bacteria (including pathogens such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and fungi (Candida tropicalis), providing novel insights into their formation mechanisms and implications, together with novel methods (e.g., use of chemical conjugates and combinations of molecules) that can be used to disrupt the biofilm structure and kill the colonizing cells.}, } @article {pmid37296327, year = {2023}, author = {Slate, AJ and Clarke, OE and Kerio, M and Nzakizawayano, J and Patel, BA and Jones, BV}, title = {Infection Responsive coatings to reduce biofilm formation and encrustation of urinary catheters.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jambio/lxad121}, pmid = {37296327}, issn = {1365-2672}, abstract = {AIMS: The care of patients undergoing long-term urethral catheterisation is frequently complicated by Proteus mirabilis infection. This organism forms dense, crystalline biofilms which block catheters leading to serious clinical conditions. However, there are currently no truly effective approaches to control this problem. Here we describe the development of a novel theranostic catheter coating, to simultaneously provide early warning of blockage, and actively delay crystalline biofilm formation.

METHODS AND RESULTS: The coating comprises of a pH sensitive upper layer of poly(methyl methacrylate-co-methacrylic acid; Eudragit S100®) and a hydrogel base layer of poly(vinyl alcohol), which is loaded with therapeutic agents (acetohydroxamic acid or ciprofloxacin hydrochloride) and the fluorescent dye 5(6)-Carboxyfluorescein (CF). The elevation of urinary pH due to P. mirabilis urease activity results in the dissolution of the upper layer and release of cargo agents contained in the base layer. Experiments using in vitro models of P. mirabilis catheter infection demonstrated that coatings significantly delay time taken for catheters to block. Coatings containing both CF dye and ciprofloxacin HCl were able to provide an average of ca. 79 h advanced warning of blockage and extend catheter lifespan ca. 3.40-fold.

CONCLUSIONS: This study has demonstrated the potential for theranostic, infection-responsive coatings to form a promising approach to combat catheter encrustation and actively delay blockage.}, } @article {pmid37295685, year = {2023}, author = {Wang, P and Lu, B and Chai, X}, title = {Rapid start-up and long-term stable operation of the anammox reactor based on biofilm process: Status, challenges, and perspectives.}, journal = {Chemosphere}, volume = {}, number = {}, pages = {139166}, doi = {10.1016/j.chemosphere.2023.139166}, pmid = {37295685}, issn = {1879-1298}, abstract = {Anammox-biofilm processes have great potential for wastewater nitrogen removal, as it overcomes the slow growth and easy loss of AnAOB (anaerobic ammonium oxidation bacteria). Biofilm carrier is the core part of the Anammox-biofilm reactor and plays a key role in the start-up and long-term operation of the process. Therefore, the research on the biofilm carrier of Anammox-based process was summarized and discussed in terms of configurations and types. In the Anammox-biofilm process, fixed bed biofilm reactor is a relatively mature biofilm carrier configuration and has advantages in terms of nitrogen removal and long-term operational stability, while moving bed biofilm reactor has advantages in terms of start-up time. Although the long-term operational stability of fluidized bed biofilm reactor is good, its nitrogen removal performance needs to be improved. Among the different biofilm carrier categories, the inorganic biofilm carrier has an advantage in start-up time, due to the enhancement of the growth and metabolic of AnAOB by inorganic materials (such as carbon and iron). Anammox-based reactors using organic biofilm carriers, especially suspension carriers, are well-established and more stable in long-term operation. Composite biofilm carriers combine the advantages of several materials, but their complex preparation procedures lead to high costs. In addition, possible research directions for accelerating the start-up and keeping the long-term stable operation of Anammox reactor by biofilm process were highlighted. It is hoped to provide a possible pathway for the rapid start-up of Anammox-based process, and references for the optimization and promotion of process.}, } @article {pmid37295405, year = {2023}, author = {Vidakovic, L and Mikhaleva, S and Jeckel, H and Nisnevich, V and Strenger, K and Neuhaus, K and Raveendran, K and Ben-Moshe, NB and Aznaourova, M and Nosho, K and Drescher, A and Schmeck, B and Schulte, LN and Persat, A and Avraham, R and Drescher, K}, title = {Biofilm formation on human immune cells is a multicellular predation strategy of Vibrio cholerae.}, journal = {Cell}, volume = {186}, number = {12}, pages = {2690-2704.e20}, pmid = {37295405}, issn = {1097-4172}, mesh = {Animals ; Humans ; *Vibrio cholerae/metabolism ; Predatory Behavior ; Biofilms ; Fimbriae, Bacterial ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Biofilm formation is generally recognized as a bacterial defense mechanism against environmental threats, including antibiotics, bacteriophages, and leukocytes of the human immune system. Here, we show that for the human pathogen Vibrio cholerae, biofilm formation is not only a protective trait but also an aggressive trait to collectively predate different immune cells. We find that V. cholerae forms biofilms on the eukaryotic cell surface using an extracellular matrix comprising primarily mannose-sensitive hemagglutinin pili, toxin-coregulated pili, and the secreted colonization factor TcpF, which differs from the matrix composition of biofilms on other surfaces. These biofilms encase immune cells and establish a high local concentration of a secreted hemolysin to kill the immune cells before the biofilms disperse in a c-di-GMP-dependent manner. Together, these results uncover how bacteria employ biofilm formation as a multicellular strategy to invert the typical relationship between human immune cells as the hunters and bacteria as the hunted.}, } @article {pmid37295142, year = {2023}, author = {Chen, K and Zhan, Z and Li, L and Li, J and Zhou, Z and Wang, N and Sun, D and Xu, C and Chen, P and Qu, X and Liao, M and Zhang, J}, title = {BolA affects the biofilm formation ability, outer membrane permeability and virulence, thus is required for the adaptability of Salmonella enterica serotype Typhimurium to the harsh survival environment.}, journal = {Microbiological research}, volume = {274}, number = {}, pages = {127423}, doi = {10.1016/j.micres.2023.127423}, pmid = {37295142}, issn = {1618-0623}, abstract = {Salmonella enterica serotype Typhimurium, an important foodborne pathogen with high adaptability to the host's internal and external survival environment, seriously threatens public health. Therefore, to understand the mechanism underlying the high adaptability, this study investigated the transcription factor BolA by constructing BolA deletion strain 269△BolA, complemented strain 269BolAR and overexpression strain 269BolA+ based on WT269. BolA significantly inhibited motility; at 6 h, the BolA overexpression strain (269BolA+) showed 91.2% and 90.7% lower motility than the wild type (WT269) and BolA deletion strain (269△BolA), respectively, by downregulating motility-related flagellar genes. BolA promoted biofilm formation; 269BolA+ showed 3.6-fold and 5.2-fold higher biofilm formation ability than WT269 and 269ΔBolA, respectively, by upregulation biofilm formation-related genes. BolA overexpression downregulated the outer membrane gene OmpF and upregulated OmpC, thereby regulating cell permeability, and reducing the antibacterial effect of vancomycin, which can destruct the outer membrane. BolA improved adaptability; 269△BolA showed higher susceptibility to eight antibiotics and 2.5- and 4-fold lower acid and oxidative stress tolerance, respectively, than WT269. In Caco-2 and HeLa cells, 269△BolA showed 2.8- and 3-fold lower cell adhesion ability, respectively, and 4- and 2-fold lower cell invasion ability, respectively, than WT269, through downregulation of the virulence genes. Thus, BolA expression promotes biofilm formation and balances the membrane permeability, thereby improving the resistance of the strains, and enhances its host cell invasion ability by upregulating bacterial virulence factors. Results of this study suggest that the BolA gene may serve as a potential target of therapeutic or preventative strategies to control Salmonella Typhimurium infections.}, } @article {pmid37294506, year = {2023}, author = {Avukat, EN and Akay, C and Topcu Ersöz, MB and Mumcu, E and Pat, S and Erdönmez, D}, title = {Could Helium Plasma Treatment be a Novel Approach to Prevent the Biofilm Formation of Candida albicans?.}, journal = {Mycopathologia}, volume = {}, number = {}, pages = {}, pmid = {37294506}, issn = {1573-0832}, abstract = {There is no definitive method to prevent Candida albicans (C. albicans) biofilm formation on polymethyl methacrylate (PMMA) surfaces. The objective of this study was to evaluate the effect of Helium plasma treatment (before the application of removable dentures to the patient) to prevent or reduce C. albicans ATCC 10,231 the anti-adherent activity, viability, and biofilm formation on PMMA surfaces. One hundred disc-shaped PMMA samples (2 mm × 10 mm) were prepared. The samples were randomly divided into 5 surface groups and treated with different concentrations of Helium plasma: G I: Control group (untreated), G II: 80% Helium plasma-treated group, G III: 85% Helium plasma-treated group, G IV: 90% Helium plasma-treated group, G V: 100% Helium plasma-treated group. C. albicans viability and biofilm formations were evaluated using 2 methods: MTT (3-(4,5-dimethyl thiazolyl-2)-2, 5-diphenyltetrazolium bromide) assays and Crystal Violet (CV) staining. The surface morphology and C. albicans biofilm images were observed with scanning electron microscopy. The Helium plasma-treated PMMA groups (G II, G III, G IV, G V) observed a significant reduction in C. albicans cell viability and biofilm formation compared with the control group. Treating PMMA surfaces with different concentrations of Helium plasma prevents C. albicans viability and biofilm formation. This study suggests that Helium plasma treatment might be an effective strategy in modifying PMMA surfaces to prevent denture stomatitis formation.}, } @article {pmid37294289, year = {2023}, author = {Wilkinson, D and Alsharaf, L and Thompson, S and Paulin, A and Takor, R and Zaitoun, A and Robinson, K and Thomas, J and McVicker, G and Winter, J}, title = {Characterization of a Helicobacter pylori strain with high biofilm-forming ability.}, journal = {Journal of medical microbiology}, volume = {72}, number = {6}, pages = {}, doi = {10.1099/jmm.0.001710}, pmid = {37294289}, issn = {1473-5644}, mesh = {Humans ; *Helicobacter pylori ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Helicobacter Infections/microbiology ; }, abstract = {Introduction. Helicobacter pylori is highly polymorphic, and some strains are much more likely to cause disease than others. Biofilm formation can help bacteria to survive antibiotic treatment, immune attack and other stresses, promoting persistent infection.Hypothesis/Gap Statement. We hypothesized that H. pylori isolates from patients with more severe H. pylori-associated disease would be better at forming biofilms than isolates from patients with less severe disease.Aim. We initially aimed to determine whether or not the biofilm-forming ability of H. pylori isolates was associated with disease in the UK-based patients from whom the bacteria were isolated.Methodology. Biofilm-forming ability of H. pylori isolates was determined using a crystal violet assay on glass coverslips. The complete genome sequence of strain 444A was generated by hybrid assembly of Nanopore MinION and Illumina MiSeq data.Results. Although we found no associations between biofilm-forming ability of H. pylori and disease severity in patients, we discovered that strain 444A had particularly high biofilm-forming ability. This strain had been isolated from a patient with gastric ulcer disease and moderate to severe scores for H. pylori-induced histopathology. Analysis of the genome of the high biofilm-forming H. pylori strain 444A revealed that it possesses numerous biofilm- and virulence-associated genes and a small cryptic plasmid encoding a type II toxin-antitoxin system.Conclusion. There is substantial variation in biofilm-forming ability in H. pylori, but this was not significantly associated with disease severity in our study. We identified and characterized an interesting strain with high biofilm-forming ability, including generation and analysis of the complete genome.}, } @article {pmid37293313, year = {2023}, author = {Tang, R and Ren, Y and Zhang, Y and Yin, M and Ren, X and Zhu, Q and Gao, C and Zhang, W and Liu, G and Liu, B}, title = {Glucose-driven transformable complex eliminates biofilm and alleviates inflamm-aging for diabetic periodontitis therapy.}, journal = {Materials today. Bio}, volume = {20}, number = {}, pages = {100678}, pmid = {37293313}, issn = {2590-0064}, abstract = {Diabetic periodontitis is a major complication of diabetes, which has a deep involvement in teeth loss and more serious systematic diseases, including Alzheimer's disease, atherosclerosis and cancers. Diabetic periodontitis is difficult to treat because of recalcitrant infection and hyperglycemia-induced tissue dysfunction. Current treatments fail to completely eliminate infection due to the diffusion-reaction inhibition of biofilm, and ignore the tissue dysfunction. Here, we design a glucose-driven transformable complex, composed of calcium alginate (CaAlg) hydrogel shell and Zeolitic imidazolate framework-8 (ZIF-8) core encapsulating Glucose oxidase (GOx)/Catalase (CAT) and Minocycline (MINO), named as CaAlg@MINO/GOx/CAT/ZIF-8 (CMGCZ). The reaction product of glucose-scavenging, gluconic acid, could dissolve ZIF-8 core and transform CMGCZ from inflexible to flexible, facilitating the complex to overcome the diffusion-reaction inhibition of biofilm. Meanwhile, reduced glucose concentration could ameliorate the pyroptosis of macrophages to decrease the secretion of pro-inflammatory factors, thereby reducing inflamm-aging to alleviate periodontal dysfunction.}, } @article {pmid37291762, year = {2023}, author = {van Alin, A and Corbett, MK and Fathollahzadeh, H and Tjiam, MC and Rickard, WDA and Sun, X and Putnis, A and Eksteen, J and Kaksonen, AH and Watkin, E}, title = {Biofilm formation on the surface of monazite and xenotime during bioleaching.}, journal = {Microbial biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1751-7915.14260}, pmid = {37291762}, issn = {1751-7915}, support = {DP200103243//Australian Research Council/ ; //Institute for Geoscience Research/ ; }, abstract = {Microbial attachment and biofilm formation is a ubiquitous behaviour of microorganisms and is the most crucial prerequisite of contact bioleaching. Monazite and xenotime are two commercially exploitable minerals containing rare earth elements (REEs). Bioleaching using phosphate solubilizing microorganisms is a green biotechnological approach for the extraction of REEs. In this study, microbial attachment and biofilm formation of Klebsiella aerogenes ATCC 13048 on the surface of these minerals were investigated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In a batch culture system, K. aerogenes was able to attach and form biofilms on the surface of three phosphate minerals. The microscopy records showed three distinctive stages of biofilm development for K. aerogenes commencing with initial attachment to the surface occurring in the first minutes of microbial inoculation. This was followed by colonization of the surface and formation of a mature biofilm as the second distinguishable stage, with progression to dispersion as the final stage. The biofilm had a thin-layer structure. The colonization and biofilm formation were localized toward physical surface imperfections such as cracks, pits, grooves and dents. In comparison to monazite and xenotime crystals, a higher proportion of the surface of the high-grade monazite ore was covered by biofilm which could be due to its higher surface roughness. No selective attachment or colonization toward specific mineralogy or chemical composition of the minerals was detected. Finally, in contrast to abiotic leaching of control samples, microbial activity resulted in extensive microbial erosion on the high-grade monazite ore.}, } @article {pmid37290619, year = {2023}, author = {Jang, D and Won, J and Jo, Y and Kim, YO and Jang, A}, title = {Effect of biocarriers on the nitrification and microbial community in moving bed biofilm reactor for anaerobic digestion effluent treatment.}, journal = {Environmental research}, volume = {232}, number = {}, pages = {116350}, doi = {10.1016/j.envres.2023.116350}, pmid = {37290619}, issn = {1096-0953}, abstract = {The performance of a moving bed biofilm reactor (MBBR) depends largely on the type of biofilm carrier used. However, how different carriers affect the nitrification process, particularly when treating anaerobic digestion effluents, is not completely understood. This study aimed to evaluate the nitrification performance of two distinct biocarriers in MBBRs over a 140-d operation period, with a gradually decreasing hydraulic retention time (HRT) from 20 to 10 d. Reactor 1 (R1) was filled with fiber balls, whereas a Mutag Biochip was used for reactor 2 (R2). At an HRT of 20 d, the ammonia removal efficiency of both reactors was >95%. However, as the HRT was reduced, the ammonia removal efficiency of R1 gradually declined, ultimately dropping to 65% at a 10-d HRT. In contrast, the ammonia removal efficiency of R2 consistently exceeding 99% throughout the long-term operation. R1 exhibited partial nitrification, whereas R2 exhibited complete nitrification. Analysis of microbial communities showed that the abundance and diversity of bacterial communities, particularly nitrifying bacteria such as Hyphomicrobium sp. And Nitrosomonas sp., in R2 was higher than that in R1. In conclusion, the choice of biocarrier significantly impact the abundance and diversity of microbial communities in MBBR systems. Therefore, these factors should be closely monitored to ensure the efficient treatment of high-strength ammonia wastewater.}, } @article {pmid37290506, year = {2023}, author = {Li, YQ and Zhang, CM and Yuan, QQ and Wu, K}, title = {New insight into the effect of microplastics on antibiotic resistance and bacterial community of biofilm.}, journal = {Chemosphere}, volume = {335}, number = {}, pages = {139151}, doi = {10.1016/j.chemosphere.2023.139151}, pmid = {37290506}, issn = {1879-1298}, abstract = {Microplastics (MPs) could serve as substrates for microbial colonization and biofilm formation. However, research on the effects of different types of microplastics and natural substrates on biofilm formation and community structure in the presence of antibiotic-resistant bacteria (ARB) is limited. In this study, we employed by means of microcosm experiments to analyze the situation of biofilms conditions, bacterial resistance patterns, antibiotic resistance genes (ARGs) distribution, and bacterial community on different substrates using microbial cultivation, high throughtput sequencing and PCR. The result showed that biofilms on different substrates markedly increased with time, with MPs surfaces formed more biofilm than stone. Analyses of antibiotic resistant showed negligible differences in the resistance rate to the same antibiotic at 30 d, but tetB would be selectively enriched on PP and PET. The microbial communities associated with biofilms on MPs and stones exhibited variations during different stages of formation. Notably, phylum WPS-2 and Epsilonbacteraeota were identified as the dominant microbiomes of biofilms on MPs and stones at 30 d, respectively. Correlation analysis suggested that WPS-2 could potentially be a tetracycline-resistant bacterium, while Epsilonbacteraeota did not correlate with any detected ARB. Our results emphasized the potential threat posed by MPs as attachment carriers for bacteria, particularly ARB, in aquatic environments.}, } @article {pmid37290200, year = {2023}, author = {Hsieh, PC and Chien, HW}, title = {Biomimetic surfaces: Insights on the role of surface topography and wetting properties in bacterial attachment and biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {228}, number = {}, pages = {113389}, doi = {10.1016/j.colsurfb.2023.113389}, pmid = {37290200}, issn = {1873-4367}, abstract = {The study explores the impact of biomimetic surfaces on bacterial attachment and biofilm formation. Specifically, it investigates the effects of topographic scale and wetting behavior on the attachment and growth of Staphylococcus aureus and Escherichia coli on four different biomimetic surfaces: rose petals, Paragrass leaves, shark skin, and goose feathers. Using soft lithography, epoxy replicas with surface topographies similar to those of the natural surfaces were created. The static water contact angles of the replicas exceeded the hydrophobic threshold of 90°, while the hysteresis angles were found to be in the order of goose feathers, shark skin, Paragrass leaves, and rose petals. The results showed that bacterial attachment and biofilm formation were the lowest on rose petals and the highest on goose feathers, regardless of the bacterial strain. Additionally, the study revealed that surface topography had a significant impact on biofilm formation, with smaller feature sizes inhibiting biofilm formation. Hysteresis angle, rather than static water contact angle, was identified as a critical factor to consider when evaluating bacterial attachment behavior. These unique insights have the potential to lead to the development of more effective biomimetic surfaces for the prevention and eradication of biofilms, ultimately improving human health and safety.}, } @article {pmid37290199, year = {2023}, author = {Gędas, A and Draszanowska, A and den Bakker, H and Diez-Gonzalez, F and Simões, M and Olszewska, MA}, title = {Prevention of surface colonization and anti-biofilm effect of selected phytochemicals against Listeria innocua strain.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {228}, number = {}, pages = {113391}, doi = {10.1016/j.colsurfb.2023.113391}, pmid = {37290199}, issn = {1873-4367}, abstract = {This work aimed to determine the ability of Listeria innocua (L.i.) to colonize eight materials found in food-processing and packaging settings and to evaluate the viability of the sessile cells. We also selected four commonly used phytochemicals (trans-cinnamaldehyde, eugenol, citronellol, and terpineol) to examine and compare their efficacies against L.i. on each surface. Biofilms were also deciphered in chamber slides using confocal laser scanning microscopy to learn more about how phytochemicals affect L.i. The materials tested were silicone rubber (Si), polyurethane (PU), polypropylene (PP), polytetrafluoroethylene (PTFE), stainless steel 316 L (SS), copper (Cu), polyethylene terephthalate (PET), and borosilicate glass (GL). L.i. colonized Si and SS abundantly, followed by PU, PP, Cu, PET, GL, and PTFE surfaces. The live/dead status ranged from 65/35% for Si to 20/80% for Cu, and the estimates of cells unable to grow on Cu were the highest, reaching even 43%. Cu was also characterized by the highest degree of hydrophobicity (ΔG[TOT] = -81.5 mJ/m[2]). Eventually, it was less prone to attachment, as we could not recover L.i. after treatments with control or phytochemical solutions. The PTFE surface demonstrated the least total cell densities and fewer live cells (31%) as compared to Si (65%) or SS (nearly 60%). It also scored high in hydrophobicity degree (ΔG[TOT] = -68.9 mJ/m[2]) and efficacy of phytochemical treatments (on average, biofilms were reduced by 2.1 log10 CFU/cm[2]). Thus, the hydrophobicity of surface materials plays a role in cell viability, biofilm formation, and then biofilm control and could be the prevailing parameter when designing preventive measures and interventions. As for phytochemical comparison, trans-cinnamaldehyde displayed greater efficacies, with the highest reductions seen on PET and Si (4.6 and 4.0 log10 CFU/cm[2]). The biofilms in chamber slides exposed to trans-cinnamaldehyde revealed the disrupted organization to a greater extent than other molecules. This may help establish better interventions via proper phytochemical selection for incorporation in environment-friendly disinfection approaches.}, } @article {pmid37290194, year = {2023}, author = {Wang, L and Kang, X and Liu, Y and Huang, X}, title = {Free ammonia-free nitrous acid based partial nitrification in sequencing batch membrane aerated biofilm reactor.}, journal = {Water research}, volume = {241}, number = {}, pages = {120168}, doi = {10.1016/j.watres.2023.120168}, pmid = {37290194}, issn = {1879-2448}, mesh = {*Nitrous Acid ; *Ammonia/chemistry ; Nitrification ; Bioreactors/microbiology ; Nitrites ; Bacteria ; Biofilms ; Oxidation-Reduction ; }, abstract = {Membrane aerated biofilm reactor (MABR) has attracted a lot of attention as an energy-efficient integrated nitrogen removing technology in recent years. However, it is lacking of understanding to realize stable partial nitrification in MABR because of its unique oxygen transfer mode and biofilm structure. In this study, free ammonia (FA) and free nitrous acid (FNA) based control strategies for partial nitrification with low NH4[+]-N concentration were proposed in a MABR of sequencing batch mode. The MABR was operated for over 500 days under different influent NH4[+]-N concentrations. With the influent NH4[+]-N of around 200 mg-N/L, partial nitrification could be established with relatively low concentration of FA (0.4-2.2 mg-N/L) which suppressed nitrite oxidizing bacteria (NOB) on the biofilm. With lower influent NH4[+]-N concentration of around 100 mg-N/L, the FA concentration was lower and strengthened suppression strategies based on FNA were needed. With the final pH of operating cycles below 5.0, the FNA produced in the sequencing batch MABR could stabilize partial nitrification by eliminating NOB on the biofilm. Since the activity of ammonia oxidizing bacteria (AOB) was lower without the blow-off of dissolved carbon dioxide in the bubbleless MABR, longer hydraulic retention time was required to reach a low pH for high concentration of FNA to suppress NOB. After exposures to FNA, the relative abundance of Nitrospira was decreased by 94.6%, while the abundance of Nitrosospira increased greatly which became another dominant AOB genus in addition to Nitrosomonas.}, } @article {pmid37289487, year = {2023}, author = {Rather, SA and Majeed, A and Singh, L and Bhatia, A and Sharma, SC and Mahmood, A}, title = {Effect of dextransucrase antibodies on biofilm formation and certain cariogenic activities in Streptococcus mutans.}, journal = {Journal of medical microbiology}, volume = {72}, number = {6}, pages = {}, doi = {10.1099/jmm.0.001696}, pmid = {37289487}, issn = {1473-5644}, mesh = {Animals ; Humans ; Rabbits ; *Streptococcus mutans/genetics ; Biofilms ; *Dental Caries/prevention & control ; Glucosyltransferases ; }, abstract = {Introduction. Dextransucrase produced by Streptococcus mutans plays a vital role in the formation of dental caries by synthesizing exopolysaccharides from sucrose, which helps in the attachment of microbes to the tooth surface, causing caries. Exploring antibody production against S. mutans antigens could be an effective method to protect against dental caries.Hypothesis. Dextransucrase antibodies may help in the prevention of caries formation by inhibiting essential cariogenic factors.Aims. The aim of this study was to investigate the effects of dextransucrase antibodies on biofilm formation and certain associated cariogenic factors of S. mutans.Methodology. Dextransucrase was purified from culture of S. mutans. The antisera against the enzyme were raised in rabbits. The effect of dextransucrase antibodies on biofilm formation was studied using scanning electron microscopy, fluorescence microscopy and quantitative real-time polymerase chain reaction. The effects of the antibodies on associated cariogenic factors were examined using established methods. The cross-reactivity of antibodies with human lung, liver, heart, thyroid and kidney tissues was evaluated by immunohistochemistry.Results. Our findings showed impaired biofilm formation in S. mutans in the presence of dextransucrase antibodies. Genes associated with biofilm formation such as gtfB, gtfC, brpA, relA, Smu.630 and vicK were downregulated (50-97 %) by dextransucrase antibodies in S. mutans. The adherence of S. mutans to glass surface was reduced by 58 % and hydrophobicity was reduced by 55.2 % in the presence of the antibodies compared to the controls. Immunohistochemistry studies revealed no cross-reactivity of human tissues with dextransucrase antibodies.Conclusions. These findings suggest that antibodies raised against dextransucrase exhibit a profound inhibitory effect on biofilm formation and vital cariogenic factors of S. mutans, which supports the contention that dextransucrase could be a promising antigen to study for its anticariogenic potential.}, } @article {pmid37286543, year = {2023}, author = {Quendera, AP and Pinto, SN and Pobre, V and Antunes, W and Bonifácio, VDB and Arraiano, CM and Andrade, JM}, title = {The ribonuclease PNPase is a key regulator of biofilm formation in Listeria monocytogenes and affects invasion of host cells.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {34}, pmid = {37286543}, issn = {2055-5008}, mesh = {Humans ; *Listeria monocytogenes/genetics ; Ribonucleases/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Quorum Sensing ; }, abstract = {Biofilms provide an environment that protects microorganisms from external stresses such as nutrient deprivation, antibiotic treatments, and immune defences, thereby creating favorable conditions for bacterial survival and pathogenesis. Here we show that the RNA-binding protein and ribonuclease polynucleotide phosphorylase (PNPase) is a positive regulator of biofilm formation in the human pathogen Listeria monocytogenes, a major responsible for food contamination in food-processing environments. The PNPase mutant strain produces less biofilm biomass and exhibits an altered biofilm morphology that is more susceptible to antibiotic treatment. Through biochemical assays and microscopical analysis, we demonstrate that PNPase is a previously unrecognized regulator of the composition of the biofilm extracellular matrix, greatly affecting the levels of proteins, extracellular DNA, and sugars. Noteworthy, we have adapted the use of the fluorescent complex ruthenium red-phenanthroline for the detection of polysaccharides in Listeria biofilms. Transcriptomic analysis of wild-type and PNPase mutant biofilms reveals that PNPase impacts many regulatory pathways associated with biofilm formation, particularly by affecting the expression of genes involved in the metabolism of carbohydrates (e.g., lmo0096 and lmo0783, encoding PTS components), of amino acids (e.g., lmo1984 and lmo2006, encoding biosynthetic enzymes) and in the Agr quorum sensing-like system (lmo0048-49). Moreover, we show that PNPase affects mRNA levels of the master regulator of virulence PrfA and PrfA-regulated genes, and these results could help to explain the reduced bacterial internalization in human cells of the ΔpnpA mutant. Overall, this work demonstrates that PNPase is an important post-transcriptional regulator for virulence and adaptation to the biofilm lifestyle of Gram-positive bacteria and highlights the expanding role of ribonucleases as critical players in pathogenicity.}, } @article {pmid37285769, year = {2023}, author = {Wang, S and Li, J and Wang, W and Zhou, C and Chi, Y and Wang, J and Li, Y and Zhang, Q}, title = {An overview of recent advances and future prospects of three-dimensional biofilm electrode reactors (3D-BERs).}, journal = {Journal of environmental management}, volume = {342}, number = {}, pages = {118192}, doi = {10.1016/j.jenvman.2023.118192}, pmid = {37285769}, issn = {1095-8630}, mesh = {*Anti-Bacterial Agents ; *Biofilms ; Electrodes ; }, abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) have attracted extensive attention in recent years due to their wide application range, high efficiency and energy saving. On the basis of traditional bio-electrochemical reactor, 3D-BERs are filled with particle electrodes, also known as the third electrodes, which can not only be used as a carrier for microbial growth, but also improve the electron transfer rate of the whole system. This paper reviews the constitution, advantages and basic principles of 3D-BERs as well as current research status and progress of 3D-BERs in recent years. The selection of electrode materials, including cathode, anode and particle electrode are listed and analyzed. Different constructions of reactors, like 3D-unipolar extended reactor and coupled 3D-BERs are introduced and discussed. Various contaminants degraded by 3D-BERs including nitrogen, azo dyes, antibiotics and the others are calculated and the corresponding degradation effects are described. The influencing factors and mechanisms are also introduced. At the same time, according to the research advances of 3D-BERs, the shortcomings and weakness of this technology in the current research process are analyzed, and the future research direction of this technology is prospected. This review aims to summarize recent studies of 3D-BERs in bio-electrochemical reaction and open a bright window to this booming research theme.}, } @article {pmid37285689, year = {2023}, author = {Chandra, K and Nair, AV and Chatterjee, R and Muralidhara, P and Singh, A and Kamanna, S and Tatu, US and Chakravortty, D}, title = {Absence of proline-peptide transporter YjiY in Salmonella Typhimurium leads to secretion of factors which inhibits intra-species biofilm formation.}, journal = {Microbiological research}, volume = {273}, number = {}, pages = {127411}, doi = {10.1016/j.micres.2023.127411}, pmid = {37285689}, issn = {1618-0623}, mesh = {Humans ; *Salmonella typhimurium/genetics/metabolism ; Membrane Transport Proteins/metabolism ; *Typhoid Fever ; Biofilms ; Proline/metabolism ; }, abstract = {Salmonella is a genus of widely spread Gram negative, facultative anaerobic bacteria, which is known to cause ¼th of diarrheal morbidity and mortality globally. It causes typhoid fever and gastroenteritis by gaining access to the host gut through contaminated food and water. Salmonella utilizes its biofilm lifestyle to strongly resist antibiotics and persist in the host. Although biofilm removal or dispersal has been studied widely, the inhibition of the initiation of Salmonella Typhimurium (STM WT) biofilm remains elusive. This study demonstrates the anti-biofilm property of the cell-free supernatant obtained from a carbon-starvation induced proline peptide transporter mutant (STM ΔyjiY) strain. The STM ΔyjiY culture supernatant primarily inhibits biofilm initiation by regulating biofilm-associated transcriptional network that is reversed upon complementation (STM ΔyjiY:yjiY). We demonstrate that abundance of FlgM correlates with the absence of flagella in the STM ΔyjiY supernatant treated WT cells. NusG works synergistically with the global transcriptional regulator H-NS. Relatively low abundances of flavoredoxin, glutaredoxin, and thiol peroxidase might lead to accumulation of ROS within the biofilm, and subsequent toxicity in STM ΔyjiY supernatant. This work further suggests that targeting these oxidative stress relieving proteins might be a good choice to reduce Salmonella biofilm.}, } @article {pmid37285134, year = {2023}, author = {Ahirwar, P and Kozlovskaya, V and Nijampatnam, B and Rojas, EM and Pukkanasut, P and Inman, D and Dolmat, M and Law, AC and Schormann, N and Deivanayagam, C and Harber, GJ and Michalek, SM and Wu, H and Kharlampieva, E and Velu, SE}, title = {Hydrogel-Encapsulated Biofilm Inhibitors Abrogate the Cariogenic Activity of Streptococcus mutans.}, journal = {Journal of medicinal chemistry}, volume = {66}, number = {12}, pages = {7909-7925}, doi = {10.1021/acs.jmedchem.3c00272}, pmid = {37285134}, issn = {1520-4804}, mesh = {Rats ; Animals ; *Streptococcus mutans ; Hydrogels ; *Dental Caries/drug therapy ; Biofilms ; }, abstract = {We designed and synthesized analogues of a previously identified biofilm inhibitor IIIC5 to improve solubility, retain inhibitory activities, and to facilitate encapsulation into pH-responsive hydrogel microparticles. The optimized lead compound HA5 showed improved solubility of 120.09 μg/mL, inhibited Streptococcus mutans biofilm with an IC50 value of 6.42 μM, and did not affect the growth of oral commensal species up to a 15-fold higher concentration. The cocrystal structure of HA5 with GtfB catalytic domain determined at 2.35 Å resolution revealed its active site interactions. The ability of HA5 to inhibit S. mutans Gtfs and to reduce glucan production has been demonstrated. The hydrogel-encapsulated biofilm inhibitor (HEBI), generated by encapsulating HA5 in hydrogel, selectively inhibited S. mutans biofilms like HA5. Treatment of S. mutans-infected rats with HA5 or HEBI resulted in a significant reduction in buccal, sulcal, and proximal dental caries compared to untreated, infected rats.}, } @article {pmid37284766, year = {2023}, author = {Bozan, M and Schmidt, M and Musat, N and Schmid, A and Adrian, L and Bühler, K}, title = {Spatial organization and proteome of a dual-species cyanobacterial biofilm alter among N2-fixing and non-fixing conditions.}, journal = {mSystems}, volume = {}, number = {}, pages = {e0030223}, doi = {10.1128/msystems.00302-23}, pmid = {37284766}, issn = {2379-5077}, abstract = {Many disciplines have become increasingly interested in cyanobacteria, due to their ability to fix CO2 while using water and sunlight as electron and energy sources. Further, several species of cyanobacteria are also capable of fixing molecular nitrogen, making them independent of the addition of nitrate or ammonia. Thereby they hold huge potential as sustainable biocatalysts. Here, we look into a dual-species biofilm consisting of filamentous diazotrophic cyanobacteria Tolypothrix sp. PCC 7712 and heterotrophic bacteria Pseudomonas taiwanensis VLB 120 growing in a capillary biofilm reactor. Such systems have been reported to enable high cell densities continuous process operation. By combining confocal laser scanning and helium-ion microscopy with a proteomics approach, we examined these organisms' interactions under two nitrogen-feeding strategies: N2-fixing and nitrate assimilation. Not only did Pseudomonas facilitate the biofilm formation by forming a carpet layer on the surface area but also did N2-fixing biofilms show greater attachment to the surface. Pseudomonas proteins related to surface and cell attachments were observed in N2-fixing biofilms in particular. Furthermore, co-localized biofilm cells displayed a resilient response to extra shear forces induced by segmented media/air flows. This study highlights the role of Pseudomonas in the initial attachment process, as well as the effects of different nitrogen-feeding strategies and operation regimes on biofilm composition and growth.IMPORTANCECyanobacteria are highly interesting microorganisms due to their ability to synthesize sugars from CO2 while using water and sunlight as electron and energy sources. Further, many species are also capable of utilizing molecular nitrogen, making them independent of artificial fertilizers. In this study, such organisms are cultivated in a technical system, which enables them to attach to the reactor surface, and form three-dimensional structures termed biofilms. Biofilms achieve extraordinarily high cell densities. Furthermore, this growth format allows for continuous processing, both being essential features in biotechnological process development. Understanding biofilm growth and the influence technical settings and media composition have on biofilm maturation and stability are crucial for reaction and reactor design. These findings will help to open up these fascinating organisms for applications as sustainable, resource-efficient industrial workhorses.}, } @article {pmid37283939, year = {2023}, author = {}, title = {Erratum: Baicalein Inhibits the Staphylococcus aureus Biofilm and the LuxS/AI-2 System in vitro [Corrigendum].}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {3441-3442}, doi = {10.2147/IDR.S423569}, pmid = {37283939}, issn = {1178-6973}, abstract = {[This corrects the article DOI: 10.2147/IDR.S406243.].}, } @article {pmid37283356, year = {2023}, author = {Braga, AS and Rafaela Ricci, K and Magalhães, AC}, title = {Effect of anaerobic or/and microaerophilic atmosphere on microcosm biofilm formation and tooth demineralization.}, journal = {Journal of applied oral science : revista FOB}, volume = {31}, number = {}, pages = {e20220445}, doi = {10.1590/1678-7757-2022-0445}, pmid = {37283356}, issn = {1678-7765}, mesh = {Animals ; Cattle ; Humans ; Anaerobiosis ; Biofilms ; *Dental Caries/prevention & control ; Minerals ; Streptococcus mutans ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVE: Microcosm biofilms can reproduce the complexity of a dental biofilm. However, different forms of cultivation have been used. The impact of the culture atmosphere on the development of microcosm biofilms and their potential to cause tooth demineralization has not yet been deeply studied. This study analyzes the effects of three experimental cultivation models (microaerophile vs. anaerobiosis vs. experimental mixed) on the colony-forming units (CFU) of the cariogenic microorganisms and tooth demineralization.

METHODOLOGY: 90 bovine enamel and 90 dentin specimens were distributed into different atmospheres: 1) microaerophilia (5 days, 5% CO2); 2) anaerobiosis (5 days, jar); 3) mixed (2 days microaerophilia and 3 days anaerobiosis), which were treated with 0.12% chlorhexidine (positive control - CHX) or Phosphate-Buffered Saline (negative control - PBS) (n=15). Human saliva and McBain's saliva containing 0.2% sucrose were used for microcosm biofilm formation, for 5 days. From the second day to the end of the experiment, the specimens were treated with CHX or PBS (1x1 min/day). Colony-forming units (CFU) were counted, and tooth demineralization was analyzed using transverse microradiography (TMR). Data were subjected to two-way ANOVA and Tukey's or Sidak's test (p<0.05).

RESULTS: CHX was able to reduce total microorganism's CFU compared to PBS (differences of 0.3-1.48 log10 CFU/mL), except for anaerobiosis and microaerophilia in enamel and dentin biofilm, respectively. In the case of dentin, no effect of CHX on Lactobacillus spp. was observed. CHX significantly reduced enamel demineralization compared to PBS (78% and 22% reductions for enamel and dentin, respectively). Enamel mineral loss did not differ when compared with the other atmospheres; however, the enamel lesion depth was greater under anaerobiosis. Dentin mineral loss was lower under anaerobiosis when compared with the other atmospheres.

CONCLUSION: The type of atmosphere has, in general, little influence on the cariogenic ability of the microcosm biofilm.}, } @article {pmid37283215, year = {2023}, author = {Bouloussa, H and Durand, Z and Gibon, E and Chen, AF and Grant, M and Saleh-Mghir, A and Mirza, M and Stutzman, B and Vergari, C and Yue, J and Anzala, N and Bonnot, D and Albac, S and Bouloussa, O and Croisier, D}, title = {A Novel Antibacterial Compound Decreases MRSA Biofilm Formation Without the Use of Antibiotics in A Murine Model.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {}, number = {}, pages = {}, doi = {10.1002/jor.25638}, pmid = {37283215}, issn = {1554-527X}, abstract = {Despite significant advancements in material science, surgical site infection (SSI) rates remain high and prevention is key. This study aimed to demonstrate the in-vivo safety and antibacterial efficacy of titanium implants treated with a novel broad-spectrum biocidal compound (DBG21) against methicillin-resistant Staphylococcus aureus (MRSA). Titanium (Ti) discs were covalently bound with DBG21. Untreated Ti discs were used as controls. All discs were implanted either untreated for 44 control mice or DBG21-treated for 44 treated mice. After implantation, 1x10[7] colony forming units (CFU) of MRSA were injected into the operating site. Mice were sacrificed at day 7 and 14 to determine the number of adherent bacteria (biofilm) on implants and in the peri-implant surrounding tissues. Systemic and local toxicity were assessed. At both 7 and 14 days, DBG21-treated implants yielded a significant decrease in MRSA biofilm (3.6 median log10 CFU (99.97%) reduction (p<0.001) and 1.9 median log10 CFU (98.7%) reduction (p=0.037), respectively) and peri-implant surrounding tissues (2.7 median log10 CFU/g (99.8%) reduction (p<0.001) and 5.6 median log10 CFU/g (99.9997%) reduction (p<0.001), respectively). There were no significant differences between control and treated mice in terms of systemic and local toxicity. DBG-21 demonstrated a significant decrease in the number of biofilm bacteria without associated toxicity in a small animal implant model of SSI. Preventing biofilm formation has been recognized as a key element of preventing implant-related infections. This article is protected by copyright. All rights reserved.}, } @article {pmid37279906, year = {2023}, author = {Ramírez-Paz-Y-Puente, GA and Chávez-Flores, CI and Montes-García, JF and Sanchez-Alonso, PG and Cobos-Justo, ME and Vázquez-Cruz, C and Zenteno, E and Negrete-Abascal, E}, title = {Testosterone and estradiol modify the expression of adhesins and biofilm formation in actinobacillus seminis.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnad048}, pmid = {37279906}, issn = {1574-6968}, abstract = {Actinobacillus seminis is the causal agent of epididymitis and has other effects on the reproductive tracts of small ruminants and bovines. This bacterium causes infection when luteinizing (LH) or follicle-stimulating hormones increase, and hosts reach sexual maturity. LH induces female ovulation and male testosterone production, suggesting that these hormones affect A. seminis pathogenicity. In the present study, we evaluated the effect of testosterone (1-5 ng/mL) or estradiol (5-25 pg/mL) added to culture medium on the in vitro growth, biofilm production, and adhesin expression of A. seminis. Estradiol does not promote the growth of this bacterium, whereas testosterone increased A. seminis planktonic growth twofold. Both hormones induced the expression of the elongation factor thermo unstable (EF-Tu) and phosphoglycerate mutase (PGM), proteins that A. seminis uses as adhesins. Estradiol (5 or 10 pg/mL) decreased biofilm formation by 32%, whereas testosterone, even at 5 ng/mL, showed no effect. Both hormones modified the concentrations of carbohydrates and eDNA in biofilms by 50%. Amyloid proteins are characterized by their capacity to bind Congo red (CR) dye. A. seminis binds CR dye, and this binding increases in the presence of 5 to 20 pg/mL estradiol or 4 ng/mL testosterone. The A. seminis EF-Tu protein was identified as amyloid-like protein (ALP). The effect of sexual hormones on the growth and expression of virulence factors of A. seminis seems to be relevant for its colonization and permanence in the host.}, } @article {pmid37279902, year = {2023}, author = {Maifreni, M and Bonaventura, GD and Marino, M and Guarnieri, S and Frigo, F and Pompilio, A}, title = {Biofilm formation under food-relevant conditions and sanitizers' tolerance of a Pseudomonas fluorescens group strain.}, journal = {Journal of applied microbiology}, volume = {134}, number = {6}, pages = {}, doi = {10.1093/jambio/lxad117}, pmid = {37279902}, issn = {1365-2672}, mesh = {Bacterial Adhesion ; *Pseudomonas fluorescens ; Pseudomonas ; Polystyrenes ; Biofilms ; *Disinfectants/pharmacology ; Stainless Steel ; }, abstract = {AIMS: The aim of this study was to determine the biofilm-forming ability of a strain belonging to the Pseudomonas fluorescens group isolated from the dairy environment under food-relevant conditions. Moreover, the effects of commercial sanitizers against preformed biofilms were assessed both in terms of viability and structure.

METHODS AND RESULTS: The biofilms were formed on polystyrene, stainless steel (SS), and polytetrafluoroethylene (PTFE) in a wide range of temperatures (4-25°C) and were subjected to the action of 10 different sanitizers. The strain under study showed to be a strong biofilm-former regardless of temperature, particularly on polystyrene. The biofilms were mostly sensitive to chlorine and peracetic acid-based sanitizers. For some sanitizers (e.g. amphoteric), a relationship was observed between the material and the tolerance, while the temperature was not statistically significant. The formation of long-term biofilms on SS was also structurally affected by the temperature, showing microcolonies more irregular in shape and with lower cellularity at 4°C compared to 15°C, where the biofilm was more compact and with a high presence of EPS.

CONCLUSIONS: The strain belonging to the P. fluorescens group was shown to quickly adhere and form mature biofilm at temperatures and on materials relevant to the food sector; however, biofilms formed under different conditions were differently tolerant to disinfectants.

Findings from this study could provide a basis for developing targeted sanitation protocols in food plants.}, } @article {pmid37279172, year = {2023}, author = {Chen, L and Peng, M and Zhou, J and Hu, X and Piao, Y and Li, H and Hu, R and Li, Y and Shi, L and Liu, Y}, title = {Supramolecular Photothermal Cascade Nano-Reactor Enables Photothermal Effect, Cascade Reaction, and In Situ Hydrogelation for Biofilm-Associated Tooth-Extraction Wound Healing.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2301664}, doi = {10.1002/adma.202301664}, pmid = {37279172}, issn = {1521-4095}, abstract = {Due to the emergence of drug resistance in bacteria and biofilm protection, achieving a satisfactory therapeutic effect for bacteria-infected open wounds with conventional measures is problematic. Here, we construct a photothermal cascade nano-reactor (CPNC@GOx-Fe[2+]) through a supramolecular strategy through hydrogen bonding and coordination interactions between chitosan-modified palladium nano-cube (CPNC), glucose oxidase (GOx), and ferrous iron (Fe[2+]). CPNC@GOx-Fe[2+] exhibits excellent photothermal effect and powers the GOx-assisted cascade reaction to generate hydroxyl radicals, enabling photothermal and chemodynamic combination therapy against bacteria and biofilms. Further proteomics, metabolomics, and all-atom simulation results indicate that the damage of hydroxyl radical to the function and structure of the cell membrane and the thermal effect enhances the fluidity and inhomogeneity of the bacterial cell membrane, resulting in the synergistic anti-bacterial effect. In the biofilm-associated tooth extraction wound model, hydroxyl radical generated from the cascade reaction process could initiate the radical polymerization process to form a hydrogel in situ for wound protection. In vivo experiments confirm synergistic anti-bacterial and wound protection can accelerate the healing of infected tooth-extraction wounds without affecting the oral commensal microbiota. This study provides a way to propose a multifunctional supramolecular system for the treatment of open wound infection. This article is protected by copyright. All rights reserved.}, } @article {pmid37278951, year = {2023}, author = {Pogány Simonová, M and Chrastinová, Ľ and Bino, E and Kandričáková, A and Formelová, Z and Lauková, A}, title = {Application of Autochthonous Biofilm-Forming Enterococcus hirae Kr8 Strain in Relation with Enterocin M in Broiler Rabbits and Their Effect on the Rabbit Meat Quality: Risk or Protection?.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, pmid = {37278951}, issn = {1867-1314}, support = {VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; VEGA 2/0006/17, VEGA 2/0005/21//Slovak Grant Agency VEGA of the Ministry of Education, Science, Research and Sport of the Slovak republic/ ; }, abstract = {Around weaning, rabbits are sensitive to gastrointestinal diseases, mostly of bacterial origin, including enterococci (Enterococcus hirae), clostridia, and coliforms. Preventive use of postbiotics-enterocins-as feed additives can reduce this problem. Therefore, simulation of spoilage/pathogenic environment applying the autochthonous, biofilm-forming E. hirae Kr8[+] strain in rabbits and its influence on rabbit meat quality as well as the protective effect of Ent M on rabbit meat properties and quality in infected animals was tested. Ninety-six rabbits aged 35 days, both sexes, meat line M91 breed were divided into one control (CG) and three experimental (EG1, EG2, and EG3) groups. The rabbits in CG received standard diet, without any additives, rabbits in EG1 received 10[8] CFU/mL of Kr8[+] strain (at a dose of 500 μL/animal/day), to rabbits in EG2 the Ent M (50 μL/animal/day), and in EG3, combination of the Kr8[+] and Ent M was applied in their drinking water during 21 days. The experiment lasted 42 days. The Kr8[+] strain did not attack the gastrointestinal tract and have any adverse effect on the meat quality of rabbits. Moreover, improved weight gains, carcass parameters, and higher essential fatty acid (EAA) and amino acid (EAA) content of rabbit meat point rather to its possible beneficial potential in rabbit nutrition. Administration of Ent M improved most of the tested parameters: animal weight and meat physicochemical and nutritional properties, with a focus on EFA and EAA. During combination of both additives, their synergistic impact was noted, improving the nutritional quality, mostly the EAA content of rabbit meat.}, } @article {pmid37278360, year = {2023}, author = {Zayed, N and Ghesquière, J and Kamarudin, NHN and Bernaerts, K and Boon, N and Braem, A and Van Holm, W and Teughels, W}, title = {Oral Biofilm Cryotherapy as a Novel Ecological Modulation Approach.}, journal = {Journal of dental research}, volume = {}, number = {}, pages = {220345231172688}, doi = {10.1177/00220345231172688}, pmid = {37278360}, issn = {1544-0591}, abstract = {Oral cryotherapy is used in dentistry as a safe, simple, and low-cost treatment for a variety of oral lesions. It is well known for its ability to aid in the healing process. However, its effect on oral biofilms is unknown. As a result, the purpose of this study was to assess the effects of cryotherapy on in vitro oral biofilms. In vitro multispecies oral biofilms were grown on the surface of hydroxyapatite discs in symbiotic or dysbiotic states. CryoPen X+ was used to treat the biofilms, whereas untreated biofilms served as control. One set of biofilms was collected for study immediately after cryotherapy, whereas another group was reincubated for 24 h to permit biofilm recovery. Changes in biofilm structure were analyzed with a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM), while biofilm ecology and community compositional changes were analyzed with viability DNA extraction and quantitative polymerase chain reaction (v-qPCR) analysis. One cryo-cycle immediately reduced biofilm load by 0.2 to 0.4 log10 Geq/mL, which increased with additional treatment cycles. Although the bacterial load of the treated biofilms recovered to the same level as the control biofilms within 24 h, the CLSM detected structural alterations. Compositional alterations were also detected by SEM, corroborating the v-qPCR findings that showed ≈≤10% incidence of pathogenic species compared to nontreated biofilms that encompassed ≈45% and 13% pathogenic species in dysbiotic and symbiotic biofilms, respectively. Spray cryotherapy showed promising results in a novel conceptual approach to the control of oral biofilms. Acting selectively by targeting oral pathobionts and retaining commensals, spray cryotherapy could modify the ecology of in vitro oral biofilms to become more symbiotic and prevent the evolution of dysbiosis without the use of antiseptics/antimicrobials.}, } @article {pmid37272814, year = {2023}, author = {Zhang, Y and Liu, X and Wen, H and Cheng, Z and Zhang, Y and Zhang, H and Mi, Z and Fan, X}, title = {Anti-Biofilm Enzymes-Assisted Antibiotic Therapy against Burn Wound Infection by Pseudomonas aeruginosa.}, journal = {Antimicrobial agents and chemotherapy}, volume = {}, number = {}, pages = {e0030723}, doi = {10.1128/aac.00307-23}, pmid = {37272814}, issn = {1098-6596}, abstract = {Pseudomonas aeruginosa can form biofilms at the site of burn wound, leading to infection and the failure of treatment regimens. The previous in vitro study demonstrated that a combination of the quorum-quenching enzyme AidHA147G and the extracellular matrix hydrolase PslG was effective in inhibiting biofilm and promoting antibiotic synergy. The aim of the present study was to evaluate the efficacy of this combination of enzymes in conjunction with tobramycin in treating burn wound infected with P. aeruginosa. The results showed that this treatment was effective in quorum-quenching and biofilm inhibition on infected wounds. Compared with the tobramycin treatment only, simultaneous treatment with the enzymes and antibiotics significantly reduced the severity of tissue damage, decreased the bacterial load, and reduced the expression of the inflammatory indicators myeloperoxidase (MPO) and malondialdehyde (MDA). Topical application of the enzymes also reduced the bacterial load and inflammation to some extent. These results indicate that the combined-enzyme approach is a potentially effective treatment for P. aeruginosa biofilm infections of burn wounds.}, } @article {pmid37271271, year = {2023}, author = {Hajiagha, MN and Kafil, HS}, title = {Efflux pumps and microbial biofilm formation.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {112}, number = {}, pages = {105459}, doi = {10.1016/j.meegid.2023.105459}, pmid = {37271271}, issn = {1567-7257}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Quorum Sensing ; Bacteria ; }, abstract = {Biofilm-related infections are resistant forms of pathogens that are regarded as a medical problem, particularly due to the spread of multiple drug resistance. One of the factors associated with biofilm drug resistance is the presence of various types of efflux pumps in bacteria. Efflux pumps also play a role in biofilm formation by influencing Physical-chemical interactions, mobility, gene regulation, quorum sensing (QS), extracellular polymeric substances (EPS), and toxic compound extrusion. According to the findings of studies based on efflux pump expression analysis, their role in the anatomical position within the biofilm will differ depending on the biofilm formation stage, encoding gene expression level, the type and concentration of substrate. In some cases, the function of the efflux pumps can overlap with each other, so it seems necessary to accurate identify the efflux pumps of biofilm-forming bacteria along with their function in this process. Such studies will help to choose treatment strategy, at least in combination with antibiotics. Furthermore, if the goal of treatment is an efflux pump manipulation, we should not limit it to inhibition.}, } @article {pmid37271098, year = {2023}, author = {Alshammari, M and Ahmad, A and AlKhulaifi, M and Al Farraj, D and Alsudir, S and Alarawi, M and Takashi, G and Alyamani, E}, title = {Reduction of biofilm formation of Escherichia coli by targeting quorum sensing and adhesion genes using the CRISPR/Cas9-HDR approach, and its clinical application on urinary catheter.}, journal = {Journal of infection and public health}, volume = {16}, number = {8}, pages = {1174-1183}, doi = {10.1016/j.jiph.2023.05.026}, pmid = {37271098}, issn = {1876-035X}, abstract = {BACKGROUND: Escherichia coli is a common cause of biofilm-associated urinary tract infections (UTIs). Biofilm formation in E. coli is responsible for various indwelling medical device-associated infections, including catheter-associated urinary tract infections (CAUTIs). This study aimed to reduce biofilm formation of E. coli ATCC 25922 by knocking out genes involved in quorum sensing (QS) (luxS) and adhesion (fimH and bolA) using the CRISPR/Cas9-HDR approach.

METHOD: Single-guide RNAs (sgRNAs) were designed to target luxS, fimH and bolA genes. Donor DNA for homologous recombination was constructed to provide accurate repairs of double-strand breaks (DSBs). A biofilm quantification assay (crystal violet assay) was performed to quantify the biofilm formation of mutant and wild-type strains. Morphological changes in biofilm architecture were confirmed by scanning electron microscopy (SEM). Further application of the biofilm formation of mutant and wild-type strains on urinary catheter was tested.

RESULTS: Crystal violet assay showed that the biofilm formation of ΔfimH, ΔluxS, and ΔbolA strains was significantly reduced compared to the wild-type strain (P value < 0.001). The percentage of biofilm reduction of mutant strains was as follows: ΔluxS1 77.51 %, ΔfimH1 78.37 %, ΔfimH2 84.17 %, ΔbolA1 78.24 %, and ΔbolA2 75.39 %. Microscopic analysis showed that all mutant strains lack extracellular polymeric substances (EPS) production compared to the wild-type strain, which was embedded in its EPS matrix. The adherence, cell aggregation, and biofilm formation of wild-type strain on urinary catheters were significantly higher compared to ΔfimH, ΔluxS and ΔbolA strains.

CONCLUSION: Altogether, our results demonstrated that the knockout of luxS, fimH, and bolA genes reduced EPS matrix production, which is considered the main factor in the development, maturation, and maintenance of the integrity of biofilm. This pathway could be a potential strategy to disrupt E. coli biofilm-associated UTIs. This study suggests that CRISPR/Cas9-HDR system may provide an efficient and site-specific gene editing approach that exhibits a possible antibiofilm strategy through intervention with the QS mechanism and adhesion property to suppress biofilm formation associated with UTI catheter infections.}, } @article {pmid37270584, year = {2023}, author = {Ma, Y and Deng, Y and Hua, H and Khoo, BL and Chua, SL}, title = {Distinct bacterial population dynamics and disease dissemination after biofilm dispersal and disassembly.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, pmid = {37270584}, issn = {1751-7370}, abstract = {Microbial communities that form surface-attached biofilms must release and disperse their constituent cells into the environment to colonize fresh sites for continued survival of their species. For pathogens, biofilm dispersal is crucial for microbial transmission from environmental reservoirs to hosts, cross-host transmission, and dissemination of infections across tissues within the host. However, research on biofilm dispersal and its consequences in colonization of fresh sites remain poorly understood. Bacterial cells can depart from biofilms via stimuli-induced dispersal or disassembly due to direct degradation of the biofilm matrix, but the complex heterogeneity of bacterial populations released from biofilms rendered their study difficult. Using a novel 3D-bacterial "biofilm-dispersal-then-recolonization" (BDR) microfluidic model, we demonstrated that Pseudomonas aeruginosa biofilms undergo distinct spatiotemporal dynamics during chemical-induced dispersal (CID) and enzymatic disassembly (EDA), with contrasting consequences in recolonization and disease dissemination. Active CID required bacteria to employ bdlA dispersal gene and flagella to depart from biofilms as single cells at consistent velocities but could not recolonize fresh surfaces. This prevented the disseminated bacteria cells from infecting lung spheroids and Caenorhabditis elegans in on-chip coculture experiments. In contrast, EDA by degradation of a major biofilm exopolysaccharide (Psl) released immotile aggregates at high initial velocities, enabling the bacteria to recolonize fresh surfaces and cause infections in the hosts efficiently. Hence, biofilm dispersal is more complex than previously thought, where bacterial populations adopting distinct behavior after biofilm departure may be the key to survival of bacterial species and dissemination of diseases.}, } @article {pmid37269993, year = {2023}, author = {Zhou, L and Dong, N and Fu, M and Yue, X and Jian, Y and Li, H and Russenberger, M and Zhuang, WQ}, title = {Dissimilatory sulfate reduction in an anaerobic biofilm reactor for tofu processing wastewater treatment: Bacterial community and their functional genes.}, journal = {The Science of the total environment}, volume = {892}, number = {}, pages = {164579}, doi = {10.1016/j.scitotenv.2023.164579}, pmid = {37269993}, issn = {1879-1026}, abstract = {Dissimilatory sulfate reduction (DSR) is the key sulfur cycle that transforms sulfate to sulfide. This process leads to odour issues in wastewater treatment. However, few studies have focused on DSR during treating food processing wastewater with high sulfate. This study investigated DSR microbial population and functional genes in an anaerobic biofilm reactor (ABR) treating tofu processing wastewater. The tofu processing wastewater is a common food processing wastewater in Asia. The full-scale ABR was operated for over 120 days in a tofu and tofu-related products manufacturing factory. Mass balance calculations based on the reactor performance indicated that 79.6-85.1 % of the sulfate was transformed into sulfide irrelevant to dissolved oxygen supplementation. Metagenomic analysis revealed 21 metagenome-assembled genomes (MAGs) containing enzymes encoding DSR. The biofilm contained the complete functional genes of DSR pathway in the full-scale ABR, indicating that biofilm could process DSR independently. Comamonadaceae, Thiobacillus, Nitrosomonadales, Desulfatirhabdium butyrativorans, Desulfomonile tiedjei were the dominant DSR species in the ABR biofilm community. Dissolved oxygen supplementation directly inhibited DSR and mitigated HS[-] production. It was also found that Thiobacillus contained all the function genes encoding every necessary enzyme in DSR, and thus Thiobacillus distribution directly correlated to DSR and the ABR performance.}, } @article {pmid37269809, year = {2023}, author = {Das, A and Patro, S and Simnani, FZ and Singh, D and Sinha, A and Kumari, K and Rao, PV and Singh, S and Kaushik, NK and Panda, PK and Suar, M and Verma, SK}, title = {Biofilm modifiers: The disparity in paradigm of oral biofilm ecosystem.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {164}, number = {}, pages = {114966}, doi = {10.1016/j.biopha.2023.114966}, pmid = {37269809}, issn = {1950-6007}, mesh = {Humans ; Ecosystem ; *Dental Caries ; Biofilms ; *Periodontal Diseases ; }, abstract = {A biofilm is a population of sessile microorganisms that has a distinct organized structure and characteristics like channels and projections. Good oral hygiene and reduction in the prevalence of periodontal diseases arise from minimal biofilm accumulation in the mouth, however, studies focusing on modifying the ecology of oral biofilms have not yet been consistently effective. The self-produced matrix of extracellular polymeric substances and greater antibiotic resistance make it difficult to target and eliminate biofilm infections, which lead to serious clinical consequences that are often lethal. Therefore, a better understanding is required to target and modify the ecology of biofilms in order to eradicate the infection, not only in instances of oral disorders but also in terms of nosocomial infections. The review focuses on several biofilm ecology modifiers to prevent biofilm infections, as well as the involvement of biofilm in antibiotic resistance, implants or in-dwelling device contamination, dental caries, and other periodontal disorders. It also discusses recent advances in nanotechnology that may lead to novel strategies for preventing and treating infections caused by biofilms as well as a novel outlook to infection control.}, } @article {pmid37269387, year = {2023}, author = {Aziz, SN and Al-Kadmy, IMS and Rheima, AM and Al-Sallami, KJ and Abd Ellah, NH and El-Saber Batiha, G and El-Bouseary, MM and Algammal, AM and Hetta, HF}, title = {Binary CuO\CoO nanoparticles inhibit biofilm formation and reduce the expression of papC and fimH genes in multidrug-resistant Klebsiella oxytoca.}, journal = {Molecular biology reports}, volume = {50}, number = {7}, pages = {5969-5976}, pmid = {37269387}, issn = {1573-4978}, abstract = {BACKGROUND AND AIM: Binary copper-cobalt oxide nanoparticles (CuO\CoO NPs) are modern kinds of antimicrobials, which may get a lot of interest in clinical application. This study aimed to detect the effect of the binary CuO\CoO NPs on the expression of papC and fimH genes in multidrug-resistant (MDR) isolates of Klebsiella oxytoca to reduce medication time and improve outcomes.

METHODS: Ten isolates of K. oxytoca were collected and identified by different conventional tests besides PCR. Antibiotic sensitivity and biofilm-forming ability were carried out. The harboring of papC and fimH genes was also detected. The effect of binary CuO\CoO nanoparticles on the expression of papC and fimH genes was investigated.

RESULTS: Bacterial resistance against cefotaxime and gentamicin was the highest (100%), while the lowest percentage of resistance was to amikacin (30%). Nine of the ten bacterial isolates had the ability to form a biofilm with different capacities. MIC for binary CuO\CoO NPs was 2.5 µg/mL. Gene expression of papC and fimH was 8.5- and 9-fold lower using the NPs.

CONCLUSION: Binary CuO\CoO NPs have a potential therapeutic effect against infections triggered by MDR K. oxytoca strains due to the NPs-related downregulation ability on the virulence genes of K. oxytoca.}, } @article {pmid37269176, year = {2023}, author = {Sirinirund, B and Siqueira, R and Li, J and Mendonça, G and Zalucha, J and Wang, HL}, title = {Effects of crown contour on artificial biofilm removal efficacy with interdental cleaning aids: An in vitro study.}, journal = {Clinical oral implants research}, volume = {}, number = {}, pages = {}, doi = {10.1111/clr.14105}, pmid = {37269176}, issn = {1600-0501}, abstract = {OBJECTIVES: To evaluate the efficacy of various interdental cleaning aids for artificial biofilm removal on different implant-supported crown designs.

METHODS: Mandibular models with missing first molar were fabricated and installed with single implant analogs and loaded with crowns of different designs (concave, straight, and convex). Artificial biofilm was made with occlusion spray. Thirty volunteers (periodontists, dental hygienists, and laypersons) were asked to clean the interproximal areas. The crowns were unscrewed and photographed in a standardized setting. The outcome was measured by the cleaning ratio which represents the cleaned surfaces in relation to the area of the tested surface.

RESULTS: A significant difference in favor of concave crown (p < .001) on the basal surface was cleaned by all tools, except the water flosser. There was evidence of an overall effect of "cleaning tool," "surface," and "crown design" (p < .0001) except for the "participant" factor. The mean cleaning ratio for each cleaning tool and overall combined surfaces were (in%): dental floss: 43.02 ± 23.93, superfloss: 42.51 ± 25.92, electric interspace brush: 36.21 ± 18.78, interdental brush: 29.10 ± 15.95, and electric water flosser: 9.72 ± 8.14. Dental floss and superfloss were significantly better (p < .05) than other tools in removing plaque.

CONCLUSIONS: Concave crown contour had the greatest artificial biofilm removal, followed by straight and convex crowns at the basal surface. Dental floss and superfloss were the most effective interdental cleaning devices for artificial biofilm removal. None of the tested cleaning devices were able to completely remove the artificial biofilm from the interproximal/basal surfaces.}, } @article {pmid37268049, year = {2023}, author = {Akshaya, BS and Premraj, K and Iswarya, C and Muthusamy, S and Ibrahim, HM and Khalil, HE and Ashokkumar, V and Vickram, S and Senthil Kumar, V and Palanisamy, S and Thirugnanasambantham, K}, title = {Cinnamaldehyde inhibits Enterococcus faecalis biofilm formation and promotes clearance of its colonization by modulation of phagocytes in vitro.}, journal = {Microbial pathogenesis}, volume = {181}, number = {}, pages = {106157}, doi = {10.1016/j.micpath.2023.106157}, pmid = {37268049}, issn = {1096-1208}, abstract = {The nosocomial pathogen, Enterococcus faecalis plays a crucial role in the pathogenesis of variety of infections including endocarditis, urinary tract, and recurrent root canal infections. Primary virulence factors of E. faecalis such as biofilm formation, gelatinase production and suppression of host innate immune response can severely harm host tissue. Thus, novel treatments are needed to prevent E. faecalis biofilm development and pathogenicity due to the worrisome rise in enterococcal resistance to antibiotics. The primary phytochemical in cinnamon essential oils, cinnamaldehyde, has shown promising efficacy against a variety of infections. Here, we looked into how cinnamaldehyde affected the growth of biofilms, the activity of the enzyme gelatinase, and gene expression in E. faecalis. In addition, we looked at the influence of cinnamaldehyde on RAW264.7 macrophages' interaction with biofilm and planktonic E. faecalis in terms of intracellular bacterial clearance, NO generation, and macrophage migration in vitro. According to our research, cinnamaldehyde attenuated the biofilm formation potential of planktonic E. faecalis and gelatinase activity of the biofilm at non-lethal concentrations. The expression of the quorum sensing fsr locus and its downstream gene gelE in biofilms were also found to be significantly downregulated by cinnamaldehyde. Results also demonstrated that cinnamaldehyde treatment increased NO production, intracellular bacterial clearance, and migration of RAW264.7 macrophages in presence of both biofilm and planktonic E. faecalis. Overall these results suggest that cinnamaldehyde has the ability to inhibit E. faecalis biofilm formation and modulate host innate immune response for better clearance of bacterial colonization.}, } @article {pmid37267815, year = {2023}, author = {Gupta, N and Kumar, A and Verma, VK}, title = {Strategies adopted by gastric pathogen Helicobacter pylori for a mature biofilm formation: Antimicrobial peptides as a visionary treatment.}, journal = {Microbiological research}, volume = {273}, number = {}, pages = {127417}, doi = {10.1016/j.micres.2023.127417}, pmid = {37267815}, issn = {1618-0623}, mesh = {Humans ; *Helicobacter pylori ; Antimicrobial Peptides ; *Helicobacter Infections/drug therapy ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Enormous efforts in recent past two decades to eradicate the pathogen that has been prevalent in half of the world's population have been problematic. The biofilm formed by Helicobacter pylori provides resistance towards innate immune cells, various combinatorial antibiotics, and human antimicrobial peptides, despite the fact that these all are potent enough to eradicate it in vitro. Biofilm provides the opportunity to secrete various virulence factors that strengthen the interaction between host and pathogen helping in evading the innate immune system and ultimately leading to persistence. To our knowledge, this review is the first of its kind to explain briefly the journey of H. pylori starting with the chemotaxis, the mechanism for selecting the site for colonization, the stress faced by the pathogen, and various adaptations to evade these stress conditions by forming biofilm and the morphological changes acquired by the pathogen in mature biofilm. Furthermore, we have explained the human GI tract antimicrobial peptides and the reason behind the failure of these AMPs, and how encapsulation of Pexiganan-A(MSI-78A) in a chitosan microsphere increases the efficiency of eradication.}, } @article {pmid37267807, year = {2023}, author = {Kang, T and Zhou, M and Yan, X and Song, S and Yuan, S and Yang, H and Ding, H and Jiang, H and Zhang, D and Bai, Y and Zhang, N}, title = {Biofilm formation and correlations with drug resistance in Mycoplasma synoviae.}, journal = {Veterinary microbiology}, volume = {283}, number = {}, pages = {109777}, doi = {10.1016/j.vetmic.2023.109777}, pmid = {37267807}, issn = {1873-2542}, mesh = {Animals ; *Mycoplasma synoviae ; Enrofloxacin ; Chickens ; Anti-Bacterial Agents/pharmacology ; *Mycoplasma Infections/veterinary ; Drug Resistance ; *Poultry Diseases ; }, abstract = {Infectious synovitis in chickens caused by Mycoplasma synoviae infections are characterized by exudative synovial joint membranes and tenosynovitis. We isolated M. synoviae from chickens on farms in Guangdong, China and identifed 29 K-type and 3 A-type strains using vlhA genotyping and all displayed decreased susceptibilities to enrofloxacin, doxycycline, tiamulin and tylosin compared with the type strain WVU1853 (ATCC 25204). M. synoviae biofilms were present after staining as block or continuous dot shape morphologies and these appeared as tower-like and mushroom-like structures in scanning electron micrographs. The optimal temperature for biofilm formation was 33 °C and these biofilms enhanced the resistance of M. synoviae to all 4 antibiotics we tested and minimum biofilm inhibitory concentration for enrofloxacin and biofilm biomass were significantly negatively correlated (r < 0, 0.3 ≤|r|<0.5, P < 0.05). This work is the first study of the biofilm formation ability of M. synoviae and provides the foundation for further investigations.}, } @article {pmid37267752, year = {2023}, author = {Chauhan, A and Singh, N and Kumar, R and Kushwaha, NK and Prajapati, VM and Singh, SK}, title = {GlfT1 down-regulation affects Mycobacterium tuberculosis biofilm formation and its in-vitro and in-vivo survival.}, journal = {Tuberculosis (Edinburgh, Scotland)}, volume = {141}, number = {}, pages = {102352}, doi = {10.1016/j.tube.2023.102352}, pmid = {37267752}, issn = {1873-281X}, abstract = {Mycobacterial galactan biosynthesis is critical for cell viability and growth, therefore an effort was made to study galactofuranosyl transferase 1, encoded by MRA_3822 in Mycobacterium tuberculosis H37Ra (Mtb-Ra). Galactofuranosyl transferases are involved in the biosynthesis of mycobacterial cell wall galactan chain and have been shown to be essential for in-vitro growth of Mycobacterium tuberculosis. In Mtb-Ra and Mycobacterium tuberculosis H37Rv (Mtb-Rv), two galactofuranosyl transferases are present, GlfT1 acts as initiator of galactan biosynthesis and GlfT2 continues with the subsequent polymerization events. GlfT2 has been well studied however GlfT1 inhibition/down-regulation and its effect on mycobacterial survival fitness has not been evaluated. To study the Mtb-Ra survival after GlfT1 silencing, Mtb-Ra knockdown and complemented strains were developed. In this study we show that GlfT1 down-regulation leads to increased susceptibility to ethambutol. Expression of glfT1 was up-regulated in the presence of ethambutol, and also in the presence of oxidative and nitrosative stress and upon exposure to low pH. Also, reduced biofilm formation, increased accumulation of ethidium bromide, and reduced tolerance to peroxide, nitric oxide and acid stress, were observed. The present study also demonstrates that GlfT1 down-regulation leads to reduced survival of Mtb-Ra in macrophages and in mice.}, } @article {pmid37267729, year = {2023}, author = {Peng, G and Pu, Z and Chen, F and Xu, H and Cao, X and Chun Chen, C and Wang, J and Liao, Y and Zhu, X and Pan, K}, title = {Metal leaching from plastics in the marine environment: An ignored role of biofilm.}, journal = {Environment international}, volume = {177}, number = {}, pages = {107988}, doi = {10.1016/j.envint.2023.107988}, pmid = {37267729}, issn = {1873-6750}, mesh = {*Plastics/chemistry ; Ultraviolet Rays ; Lead ; Polyesters ; Biofilms ; *Water Pollutants, Chemical/analysis ; }, abstract = {A large quantity of metal compounds in plastics are released into the marine environment every year. However, our understanding of the extent and mechanism by which polymer-bound metals leach into seawater is still limited. In this study, a comprehensive survey was conducted to measure the metal concentrations in commonly used plastics and evaluate the effects of environmental factors (temperature, radiation, and salinity) and the physiochemical properties (surface roughness, specific surface area, hydrophobicity, and crystallinity) of the plastics on their metal leaching into seawater. In particular, we observed the metal loss from six plastics submerged in coastal seawater for eight months and studied the role of biofilm in controlling the leaching of Sb, Sn, Pb, Ba, and Cr. Our results indicate that increased temperature enhanced the release of these metals, while exposure to ultraviolet radiation significantly increased the leaching of Sn from polylactide (PLA). High salinity facilitated the leaching of Sn from PLA and Pb from polyvinylchloride ball, however inhibited the leaching of Ba from PE wrap. The leaching rate was primarily determined by the inherent property of crystallinity. Metal loss from the plastics in the field was apparent during the first three weeks, but then was hindered by the development of biofilm. Our study provides the mechanisms underlying metal leaching from physical, chemical, and biological perspectives, which is useful for understanding the environmental risk of the plastic-containing metals.}, } @article {pmid37267663, year = {2023}, author = {Pedicini, L and Vannini, C and Rindi, F and Ravaglioli, C and Bertocci, I and Bulleri, F}, title = {Variations in epilithic microbial biofilm composition and recruitment of a canopy-forming alga between pristine and urban rocky shores.}, journal = {Marine environmental research}, volume = {188}, number = {}, pages = {106035}, doi = {10.1016/j.marenvres.2023.106035}, pmid = {37267663}, issn = {1879-0291}, mesh = {Animals ; Humans ; *Ecosystem ; Biodiversity ; *Phaeophyta ; Biofilms ; }, abstract = {Brown algae of the genus Ericaria are habitat formers on Mediterranean rocky shores supporting marine biodiversity and ecosystem functioning. Their population decline has prompted attempts for restoration of threatened populations. Although epilithic microbial biofilms (EMBs) are determinant for macroalgal settlement, their role in regulating the recovery of populations through the recruitment of new thalli is yet to be explored. In this study, we assessed variations in microbial biofilms composition on the settlement of Ericaria amentacea at sites exposed to different human pressures. Artificial fouling surfaces were deployed in two areas at each of three study sites in the Ligurian Sea (Capraia Island, Secche della Meloria and the mainland coast of Livorno), to allow bacterial biofilm colonization. In the laboratory, zygotes of E. amentacea were released on these surfaces to evaluate the survival of germlings. The EMB's composition was assessed through DNA metabarcoding analysis, which revealed a difference between the EMB of Capraia Island and that of Livorno. Fouling surfaces from Capraia Island had higher rates of zygote settlement than the other two sites. This suggests that different environmental conditions can influence the EMB composition on substrata, possibly influencing algal settlement rate. Assessing the suitability of rocky substrata for E. amentacea settlement is crucial for successful restoration.}, } @article {pmid37266911, year = {2023}, author = {Arndt-Fink, A and Jost-Brinkmann, PG}, title = {Investigation of the cleaning performance of commercial orthodontic cleaning tablets regarding biofilm removal on PMMA test specimens : An ex vivo study.}, journal = {Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie}, volume = {}, number = {}, pages = {}, pmid = {37266911}, issn = {1615-6714}, abstract = {PURPOSE: The purpose of this ex vivo study was to compare the cleaning performance of three commercially available orthodontic cleaners on polymethyl methacrylate (PMMA) test specimens covered with biofilm.

METHODS: Twenty subjects wore an individually manufactured vacuum-formed maxillary splint with four integrated PMMA test specimens for 7 days. The four test specimens were located on the buccal surfaces of the maxillary molars. After a 7-day wearing period, the PMMA test specimens colonized by biofilm were divided into two halves. One half was placed in 150 ml of tap water or in 150 ml of cleaning solution of the cleaners Retainer Brite® (Dentsply International Raintree Essix, Sarasota, FL, USA), Kukis® Xpress (Reckitt Benckiser, Heidelberg, Germany) or Dontodent (Propack, Heidelberg, Germany) while the other half remained uncleaned. The modified o‑phthaldialdehyde (OPA) method was used to determine the amount of protein on both halves of the test specimens. The difference was tested for significance as a measure of the cleaning effect using a paired sample t‑test.

RESULTS: The cleaning performance of the three orthodontic cleaners was higher than the cleaning performance of tap water (mean 25.9 ± 6.5%). While Retainer Brite® (mean 54.5 ± 7.1%) removed significantly more biofilm than Dontodent (mean 41.5 ± 9.2%, p < 0.001) and Kukis® Xpress (mean 39.9 ± 11.5%, p < 0.001), there was no significant difference in the cleaning performance between Kukis® Xpress and Dontodent (p = 1).

CONCLUSION: Seven-day-old biofilm is only removed partially by the investigated orthodontic cleaners, so that they are not suitable as the only measure for removing established biofilms.}, } @article {pmid37264904, year = {2023}, author = {Topcu Ersöz, MB and Mumcu, E and Avukat, EN and Akay, C and Pat, S and Erdönmez, D}, title = {Anti-adherent activity of nano-coatings deposited by thermionic vacuum arc plasma on C. albicans biofilm formation.}, journal = {The International journal of artificial organs}, volume = {}, number = {}, pages = {3913988231178041}, doi = {10.1177/03913988231178041}, pmid = {37264904}, issn = {1724-6040}, abstract = {BACKGROUND: The purpose of this study was to analyze the anti-adherent activity of nano-coatings deposited by Thermionic Vacuum Arc plasma on C. albicans ATCC 10231 biofilm.

MATERIALS AND METHODS: A total of 80 disc-shaped (2 × 10 mm) polymethymethacrylate samples were prepared and divided into four groups with 10 samples in each group (Control, ZnO, SnO2, Ag) (n = 10). Using thermionic vacuum arc plasma, they were coated with ZnO, SnO2, and Ag. 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Crystal Viole (CV) assays were conducted for biofilm quantification. Scanning electron microscopy (SEM) was used to observe biofilm images of C. albicans biofilm.

RESULTS: MTT and CV mean values differ statistically significantly between all groups (p ⩽ 0.05). The SnO2 group had the lowest mean value, whereas the control group received the highest value.

CONCLUSION: SnO2 coating shown greater anti-adherent activity than either metal oxides. C. albicans biofilm formation on denture base surfaces is reduced following Thermionic Vacuum Arc plasma coating with SnO2.}, } @article {pmid37264481, year = {2023}, author = {Liu, Y and Daniel, SG and Kim, HE and Koo, H and Korostoff, J and Teles, F and Bittinger, K and Hwang, G}, title = {Addition of cariogenic pathogens to complex oral microflora drives significant changes in biofilm compositions and functionalities.}, journal = {Microbiome}, volume = {11}, number = {1}, pages = {123}, pmid = {37264481}, issn = {2049-2618}, support = {R01 DE027970/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; Child, Preschool ; *Dental Caries ; Cross-Sectional Studies ; Candida albicans/genetics ; *Microbiota ; Biofilms ; Streptococcus mutans/genetics ; Sugars/metabolism/pharmacology ; }, abstract = {BACKGROUND: Dental caries is a microbe and sugar-mediated biofilm-dependent oral disease. Of particular significance, a virulent type of dental caries, known as severe early childhood caries (S-ECC), is characterized by the synergistic polymicrobial interaction between the cariogenic bacterium, Streptococcus mutans, and an opportunistic fungal pathogen, Candida albicans. Although cross-sectional studies reveal their important roles in caries development, these exhibit limitations in determining the significance of these microbial interactions in the pathogenesis of the disease. Thus, it remains unclear the mechanism(s) through which the cross-kingdom interaction modulates the composition of the plaque microbiome. Here, we employed a novel ex vivo saliva-derived microcosm biofilm model to assess how exogenous pathogens could impact the structural and functional characteristics of the indigenous native oral microbiota.

RESULTS: Through shotgun whole metagenome sequencing, we observed that saliva-derived biofilm has decreased richness and diversity but increased sugar-related metabolism relative to the planktonic phase. Addition of S. mutans and/or C. albicans to the native microbiome drove significant changes in its bacterial composition. In addition, the effect of the exogenous pathogens on microbiome diversity and taxonomic abundances varied depending on the sugar type. While the addition of S. mutans induced a broader effect on Kyoto Encyclopedia of Genes and Genomes (KEGG) ortholog abundances with glucose/fructose, S. mutans-C. albicans combination under sucrose conditions triggered unique and specific changes in microbiota composition/diversity as well as specific effects on KEGG pathways. Finally, we observed the presence of human epithelial cells within the biofilms via confocal microscopy imaging.

CONCLUSIONS: Our data revealed that the presence of S. mutans and C. albicans, alone or in combination, as well as the addition of different sugars, induced unique alterations in both the composition and functional attributes of the biofilms. In particular, the combination of S. mutans and C. albicans seemed to drive the development (and perhaps the severity) of a dysbiotic/cariogenic oral microbiome. Our work provides a unique and pragmatic biofilm model for investigating the functional microbiome in health and disease as well as developing strategies to modulate the microbiome. Video Abstract.}, } @article {pmid37264297, year = {2023}, author = {Fauzia, KA and Aftab, H and Miftahussurur, M and Waskito, LA and Tuan, VP and Alfaray, RI and Matsumoto, T and Yurugi, M and Subsomwong, P and Kabamba, ET and Akada, J and Yamaoka, Y}, title = {Genetic determinants of Biofilm formation of Helicobacter pylori using whole-genome sequencing.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {159}, pmid = {37264297}, issn = {1471-2180}, mesh = {Humans ; *Helicobacter pylori/genetics ; Cross-Sectional Studies ; Phylogeny ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Helicobacter Infections/drug therapy ; }, abstract = {BACKGROUND: Infection with Helicobacter pylori as the cause of gastric cancer is a global public health concern. In addition to protecting germs from antibiotics, biofilms reduce the efficacy of H. pylori eradication therapy. The nucleotide polymorphisms (SNPs) related with the biofilm forming phenotype of Helicobacter pylori were studied.

RESULTS: Fifty-six H. pylori isolate from Bangladeshi patients were included in this cross-sectional study. Crystal violet assay was used to quantify biofilm amount, and the strains were classified into high- and low-biofilm formers As a result, strains were classified as 19.6% high- and 81.4% low-biofilm formers. These phenotypes were not related to specific clades in the phylogenetic analysis. The accessories genes associated with biofilm from whole-genome sequences were extracted and analysed, and SNPs among the previously reported biofilm-related genes were analysed. Biofilm formation was significantly associated with SNPs of alpA, alpB, cagE, cgt, csd4, csd5, futB, gluP, homD, and murF (P < 0.05). Among the SNPs reported in alpB, strains encoding the N156K, G160S, and A223V mutations were high-biofilm formers.

CONCLUSIONS: This study revealed the potential role of SNPs in biofilm formation and proposed a method to detect mutation in biofilm from whole-genome sequences.}, } @article {pmid37263449, year = {2023}, author = {Zuo, J and Shen, Y and Wang, H and Gao, S and Yuan, S and Song, D and Wang, Y and Wang, Y}, title = {Effects of metformin on Streptococcus suis LuxS/AI-2 quorum sensing system and biofilm formation.}, journal = {Microbial pathogenesis}, volume = {181}, number = {}, pages = {106183}, doi = {10.1016/j.micpath.2023.106183}, pmid = {37263449}, issn = {1096-1208}, abstract = {Streptococcus suis (S. suis) regulates biofilm formation through LuxS/AI-2 quorum sensing system, increasing drug resistance and exacerbating infection. The anti-hyperglycaemic agent metformin has anti-bacterial and anti-biofilm activities. This study aimed to investigate the anti-biofilm and anti-quorum sensing activity of metformin in S. suis. We first determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of metformin on S. suis. The results indicated that metformin showed no obvious inhibitory or bactericidal effect. Crystal violet staining showed that metformin significantly inhibited the formation of S. suis biofilm at sub-MIC concentration, which was also confirmed by scanning electron microscopy. Then, we quantified the AI-2 signal molecules in S. suis, and the results showed that metformin had a significant inhibitory effect on the production of AI-2 signal in S. suis. Inhibition of enzyme activity and molecular docking experiments showed that metformin has a significant binding activity to LuxS protein. In addition, qRT-PCR results showed that metformin significantly down-regulated the expression of AI-2 synthesis-related genes luxS and pfs, and adhesion-related genes luxS, pfs, gapdh, sly, fbps, and ef. Western blotting also showed that metformin significantly reduced the expression of LuxS protein. Our study suggests that metformin seems to be a suitable candidate for the inhibition of S. suis LuxS/AI-2 QS system and prevention of biofilm formation, which provided a new idea for the prevention and control of S. suis.}, } @article {pmid37262064, year = {2023}, author = {Mei, J and Xu, D and Wang, L and Kong, L and Liu, Q and Li, Q and Zhang, X and Su, Z and Hu, X and Zhu, W and Ye, M and Wang, J and Zhu, C}, title = {Biofilm Microenvironment-Responsive Self-Assembly Nanoreactors for All-stage Biofilm Associated Infection through Bacterial Cuproptosis-like Death and Macrophage Re-rousing.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e2303432}, doi = {10.1002/adma.202303432}, pmid = {37262064}, issn = {1521-4095}, abstract = {Bacterial biofilm-associated infections (BAIs) are the leading cause of prosthetic implant failure. The dense biofilm structure prevents antibiotic penetration, while the highly acidic and H2 O2 -rich biofilm microenvironment (BME) dampens the immunological response of antimicrobial macrophages. Conventional treatments that fail to consistently suppress escaping planktonic bacteria from biofilm result in refractory recolonization, allowing BAIs to persist. Herein, we propose a BME-responsive copper-doped polyoxometalate clusters (Cu-POM) combination with mild photothermal therapy (PTT) and macrophage immune re-rousing for BAI eradication at all stages. The self-assembly of Cu-POM in BME converted endogenous H2 O2 to toxic ·OH through chemodynamic therapy (CDT) and generated a mild PTT effect to induce bacterial metabolic exuberance, resulting in loosening the membrane structure of the bacteria, enhancing copper transporter activity and increasing intracellular Cu-POM flux. Metabolomics revealed that intracellular Cu-POM overload restricted the TCA cycle and peroxide accumulation, promoting bacterial cuproptosis-like death. CDT re-rousing macrophages scavenge planktonic bacteria escaping biofilm disintegration through enhanced chemotaxis and phagocytosis. Overall, BME-responsive Cu-POM promoted bacterial cuproptosis-like death via metabolic interference, while also re-rousing macrophage immune response for further planktonic bacteria elimination, resulting in all-stage BAI clearance and providing a new reference for future clinical application. This article is protected by copyright. All rights reserved.}, } @article {pmid37260744, year = {2023}, author = {Coppens, B and Belpaire, TER and Pešek, J and Steenackers, HP and Ramon, H and Smeets, B}, title = {Anomalous diffusion of nanoparticles in the spatially heterogeneous biofilm environment.}, journal = {iScience}, volume = {26}, number = {6}, pages = {106861}, pmid = {37260744}, issn = {2589-0042}, abstract = {Biofilms contain extracellular polymeric substances (EPS) that provide structural support and restrict penetration of antimicrobial treatment. To overcome limited penetration, functionalized nanoparticles (NPs) have been suggested as carriers for antimicrobial delivery. Using microscopy, we evaluate the diffusion of nanoparticles in function of the structure of Salmonella biofilms. We observe anomalous diffusion and heterogeneous mobility of NPs resulting in distinct NPs distribution that depended on biofilm structure. Through Brownian dynamics modeling with spatially varying viscosity around bacteria, we demonstrated that spatial gradients in diffusivity generate viscous sinks that trap NPs near bacteria. This model replicates the characteristic diffusion signature and vertical distribution of NPs in the biofilm. From a treatment perspective, our work indicates that both biofilm structure and the level of EPS can impact NP drug delivery, where low levels of EPS might benefit delivery by immobilizing NPs closer to bacteria and higher levels hamper delivery due to shielding effects.}, } @article {pmid37260680, year = {2023}, author = {Bueno-Silva, B and Kiausinus, KR and Gonçalves, FJDS and Moreira, MVC and de Oliveira, EG and Brugnera Junior, A and Feres, M and Figueiredo, LC}, title = {Antimicrobial activity of Desplac® oral gel in the subgingival multispecies biofilm formation.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1122051}, pmid = {37260680}, issn = {1664-302X}, abstract = {Natural products are well-known due to their antimicrobial properties. This study aimed to evaluate the antimicrobial effect of Desplac® product (composed of Aloe Vera, Propolis Extract, Green Tea, Cranberry, and Calendula) on the subgingival biofilm. Two different protocols were used to treat the 33-species biofilms: (A) 2×/day (12/12 h) for 1 min with Desplac® or Noplak Toothpaste (Chlorhexidine + Cetylpyridinium Chloride) or Oral B ProGengiva (stannous Fluoride) or a placebo gel; (B) a 12-h use of the Desplac® product or 0.12% chlorhexidine gel or a placebo gel. After 7 days of biofilm formation, the metabolic activity (MA) and biofilm profile were determined by 2,3,5-triphenyltetrazolium chloride and Checker-board DNA-DNA hybridization, respectively. Statistical analysis used the Kruskal-Wallis test followed by Dunn's post-hoc. In protocol A, all treatments presented reduced MA compared to the placebo (p ≤ 0.05). The Desplac®-treated biofilm showed a similar microbial profile to other antimicrobials, although with higher bacterial total counts. In protocol B, MA of Desplac®-treated biofilms was lower than the placebo's MA but higher than chlorhexidine-treated biofilms (p ≤ 0.05). Pathogen levels in Desplac®-treated biofilms were lower than in placebo-treated biofilms and elevated compared to the chlorhexidine-treated biofilms (p ≤ 0.05). Desplac® inhibited the biofilm development and disrupted the mature subgingival biofilm, highlighting its effect on Tannerella forsythia counts.}, } @article {pmid37260168, year = {2023}, author = {Liu, Q and Shao, L and Liu, Z and Chen, Y and Dai, G and Ying, J}, title = {Nitric acid oxidation and urea modification of carbon fibres as biofilm carriers.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/09593330.2023.2220890}, pmid = {37260168}, issn = {1479-487X}, abstract = {Carbon fibres (CF) are commonly used as carriers in biofilm-based wastewater treatment. The surface properties of the CF are herein modified using a combination of nitric acid oxidation and urea to optimise the carrier to immobilise bacterial cells. The capacity of the CF carriers to immobilise bacterial cells and activated sludge is evaluated using bacterial cell adhesion and sludge immobilisation tests. The total interaction energy profiles between the CF supports and bacterial cells were calculated according to the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to explain the mechanism by which these modifications enhance this immobilisation capacity. CF-U has a high capacity for immobilising bacterial cells and activated sludge (3.7 g-sludge/g-CF supports) owing to its low total interaction energy. Nitric acid oxidation reduced the diiodomethane contact angle of CF from 55.1° to 38.5°, which reduced the Lifshitz-van der Waals interaction energy, while urea modification further increased the zeta potential of CF from 12.8 mV to -0.7 mV, thereby reducing the electrostatic interaction energy. Experiments and DLVO theory both determined that a combination of nitric acid oxidation and urea modification significantly enhanced the ability of CF to immobilise microorganisms.}, } @article {pmid37260114, year = {2023}, author = {Jones, GB and Sims, RC and Zhao, J}, title = {Experimental and theoretical investigations of rotating algae biofilm reactors (RABRs): Areal productivity, nutrient recovery, and energy efficiency.}, journal = {Biotechnology and bioengineering}, volume = {}, number = {}, pages = {}, doi = {10.1002/bit.28451}, pmid = {37260114}, issn = {1097-0290}, support = {//U.S. Department of Energy/ ; //National Science Foundation/ ; }, abstract = {Microalgae biofilms have been demonstrated to recover nutrients from wastewater and serve as biomass feedstock for bioproducts. However, there is a need to develop a platform to quantitatively describe microalgae biofilm production, which can provide guidance and insights for improving biomass areal productivity and nutrient uptake efficiency. This paper proposes a unified experimental and theoretical framework to investigate algae biofilm growth on a rotating algae biofilm reactor (RABR). Experimental laboratory setups are used to conduct controlled experiments on testing environmental and operational factors for RABRs. We propose a differential-integral equation-based mathematical model for microalgae biofilm cultivation guided by laboratory experimental findings. The predictive mathematical model development is coordinated with laboratory experiments of biofilm areal productivity associated with ammonia and inorganic phosphorus uptake by RABRs. The unified experimental and theoretical tool is used to investigate the effects of RABR rotating velocity, duty cycle (DC), and light intensity on algae biofilm growth, areal productivity, nutrient uptake efficiency, and energy efficiency in wastewater treatment. Our framework indicates that maintaining a reasonable light intensity range improves biomass areal productivity and nutrient uptake efficiency. Our framework also indicates that faster RABR rotation benefits biomass areal productivity. However, maximizing the nutrient uptake efficiency requires a reasonably low RABR rotating speed. Energy efficiency is strongly correlated with RABR rotating speed and DC.}, } @article {pmid37259560, year = {2023}, author = {da Silva Ribeiro, CF and Dionizio, A and Teodoro Araújo, T and Vilas Boas Feitosa Rodrigues, CM and Costa Mattos, A and Galli Otaviano, L and Tercília Grizzo, L and Magalhães, AC and Afonso Rabelo Buzalaf, M}, title = {Effect of experimental toothpaste containing hydroxyapatite nanoparticles and propolis, with and without fluoride, on the microcosm biofilm and enamel demineralization.}, journal = {Biofouling}, volume = {39}, number = {3}, pages = {339-348}, doi = {10.1080/08927014.2023.2217689}, pmid = {37259560}, issn = {1029-2454}, mesh = {Animals ; Cattle ; Humans ; Fluorides/pharmacology ; Toothpastes/pharmacology ; Cariostatic Agents/pharmacology ; *Propolis/pharmacology ; Xylitol/pharmacology ; Durapatite/pharmacology ; *Tooth Demineralization/prevention & control ; Biofilms ; *Anti-Infective Agents/pharmacology ; *Nanoparticles ; *Ascomycota ; *Dental Caries/prevention & control ; }, abstract = {This study evaluated the antimicrobial and anticaries effects of toothpaste containing hydroxyapatite nanoparticles (nanoHAP - 5 or 10%), xylitol (2 or 3%) and propolis (1 or 2%), associated or not with 1500 ppm fluoride (F). An in vitro model was used with microcosm biofilm produced from a pool of human saliva and McBain saliva (1:50) in the first 8 h of culture on 162 bovine enamel specimens. At the end of the experimental period, analyses of metabolic activity, colony forming units (CFU) and transverse microradiography (TMR) were performed. This study showed a possible decrease in demineralization and increase in remineralization by the commercial toothpaste (1500 ppm F) and for the experimental toothpaste containing the highest concentration of all agents, combined with F. In addition, a reduction in antimicrobial activity possibly caused by propolis and xylitol, mainly in relation to cariogenic bacteria, was observed.}, } @article {pmid37259419, year = {2023}, author = {Cacaci, M and Squitieri, D and Palmieri, V and Torelli, R and Perini, G and Campolo, M and Di Vito, M and Papi, M and Posteraro, B and Sanguinetti, M and Bugli, F}, title = {Curcumin-Functionalized Graphene Oxide Strongly Prevents Candida parapsilosis Adhesion and Biofilm Formation.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {2}, pages = {}, pmid = {37259419}, issn = {1424-8247}, support = {SG-2018-12366369//Governo Italiano/ ; }, abstract = {Candida parapsilosis is the major non-C. albicans species involved in the colonization of central venous catheters, causing bloodstream infections. Biofilm formation on medical devices is considered one of the main causes of healthcare-associated infections and represents a global public health problem. In this context, the development of new nanomaterials that exhibit anti-adhesive and anti-biofilm properties for the coating of medical devices is crucial. In this work, we aimed to characterize the antimicrobial activity of two different coated-surfaces, graphene oxide (GO) and curcumin-graphene oxide (GO/CU) for the first time, against C. parapsilosis. We report the capacity of GO to bind and stabilize CU molecules, realizing a homogenous coated surface. We tested the anti-planktonic activity of GO and GO/CU by growth curve analysis and quantification of Reactive Oxigen Species(ROS) production. Then, we tested the antibiofilm activity by adhesion assay, crystal violet assay, and live and dead assay; moreover, the inhibition of the formation of a mature biofilm was investigated by a viability test and the use of specific dyes for the visualization of the cells and the extra-polymeric substances. Our data report that GO/CU has anti-planktonic, anti-adhesive, and anti-biofilm properties, showing a 72% cell viability reduction and a decrease of 85% in the secretion of extra-cellular substances (EPS) after 72 h of incubation. In conclusion, we show that the GO/CU conjugate is a promising material for the development of medical devices that are refractory to microbial colonization, thus leading to a decrease in the impact of biofilm-related infections.}, } @article {pmid37258957, year = {2023}, author = {De, S and Hakansson, AP}, title = {Measuring Niche-Associated Metabolic Activity in Planktonic and Biofilm Bacteria.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2674}, number = {}, pages = {3-32}, pmid = {37258957}, issn = {1940-6029}, mesh = {Humans ; *Pneumococcal Infections/microbiology ; Plankton ; Streptococcus pneumoniae/genetics ; Biofilms ; *Otitis Media ; }, abstract = {Most pathobionts of the respiratory tract form biofilms during asymptomatic colonization to survive and persist in this niche. Environmental changes of the host niche, often resulting from infection with respiratory viruses, changes of the microbiota composition, or other host assaults, can result in biofilm dispersion and spread of bacteria to other host niches, resulting in infections, such as otitis media, pneumonia, sepsis, and meningitis. The niches that these bacteria encounter during colonization and infection vary markedly in nutritional availability and contain different carbon sources and levels of other essential nutrients needed for bacterial growth and survival. As these niche-related nutritional variations regulate bacterial behavior and phenotype, a better understanding of bacterial niche-associated metabolic activity is likely to provide a broader understanding of bacterial pathogenesis. In this chapter, we use Streptococcus pneumoniae as a model respiratory pathobiont. We describe methods and models used to grow bacteria planktonically or to form biofilms in vitro by incorporating crucial host environmental factors, including the various carbon sources associated with specific niches, such as the nasopharynx or bloodstream. We then present methods describing how these models can be used to study bacterial phenotypes and their association with metabolic energy production and the generation of fermentation products.}, } @article {pmid37257734, year = {2023}, author = {Vera-Mansilla, J and Silva-Valenzuela, CA and Sánchez, P and Molina-Quiroz, RC}, title = {Bacteriophages potentiate the effect of antibiotics by eradication of persister cells and killing of biofilm-forming cells.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104083}, doi = {10.1016/j.resmic.2023.104083}, pmid = {37257734}, issn = {1769-7123}, abstract = {Persister cells and biofilms are associated with chronic urinary infections which are more critical when generated by multi-drug resistant bacteria. In this context, joint administration of phages and antibiotics has been proposed as an alternative approach, since it may decrease the probability to generate resistant mutants to both agents. In this work, we exposed cultures of uropathogenic Escherichia coli conjunctly to antibiotics and phages. We determined that MLP2 combined with antibiotics eradicates persister cells. Similarly, MLP1 and MLP3 impact viability of biofilm-forming cells when administered with ampicillin. Our findings suggest a feasible prophylactic and therapeutic use of these non-transducing phages.}, } @article {pmid37257101, year = {2023}, author = {Rusten, B and Ødegaard, H}, title = {Nitrogen removal in moving-bed biofilm reactor plants at low temperatures: experiences from Norway.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {87}, number = {10}, pages = {2432-2440}, doi = {10.2166/wst.2023.154}, pmid = {37257101}, issn = {0273-1223}, mesh = {*Denitrification ; Temperature ; *Biofilms ; Nitrogen ; Bioreactors ; Nitrification ; Norway ; Waste Disposal, Fluid ; }, abstract = {Cold and diluted wastewater is a major challenge for nitrogen removal at wastewater treatment plants. The moving-bed biofilm reactor (MBBR) process has proven suitable for nitrogen removal under these conditions and several full-scale plants have been in operation for more than 20 years. These plants are still performing well, even at above design loads. Recently some of these plants have been evaluated for their low-temperature performance. In general, the results showed that temperatures down to 5 °C only had a minor impact on observed nitrification and denitrification rates. Higher dissolved oxygen concentrations can boost nitrification rates and are used as a tool to increase rates at low temperatures, thus partially compensating for the temperature effect. Post-denitrification rates were boosted by a controlled increase in carbon-to-nitrogen ratios at low temperatures. MBBR processes with combined pre- and post-denitrification are recommended for nitrogen-removal plants operating at low temperatures. Design recommendations and examples of flowsheets are given.}, } @article {pmid37256822, year = {2023}, author = {Tournay, RJ and Firrincieli, A and Parikh, SS and Sivitilli, DM and Doty, SL}, title = {Effect of Arsenic on EPS Synthesis, Biofilm Formation, and Plant Growth-Promoting Abilities of the Endophytes Pseudomonas PD9R and Rahnella laticis PD12R.}, journal = {Environmental science & technology}, volume = {57}, number = {23}, pages = {8728-8738}, doi = {10.1021/acs.est.2c08586}, pmid = {37256822}, issn = {1520-5851}, mesh = {*Arsenic ; Extracellular Polymeric Substance Matrix/chemistry ; Endophytes ; Pseudomonas ; *Rahnella ; Biodegradation, Environmental ; Biofilms ; Plants ; *Soil Pollutants ; }, abstract = {Phytoremediation, a cost-effective, eco-friendly alternative to conventional remediation, could expand efforts to remediate arsenic-contaminated soils. As with other pollutants, the plant microbiome may improve phytoremediation outcomes for arsenic-contaminated sites. We used in vitro and in silico methods to compare the arsenic resistance mechanisms, synthesis of extracellular polymeric substances (EPS), biofilm formation, and plant growth-promoting abilities of the endophytes Pseudomonas sp. PD9R and Rahnella laticis PD12R. PD12R, which tolerates arsenate (As(V)) and arsenite (As(III)) to concentrations fivefold greater than PD9R, synthesizes high volumes of EPS in response to arsenic, and sequesters arsenic in the capsular EPS and cells. While arsenic exposure induced EPS synthesis in both strains, only PD12R continued to form biofilms at high As(III) and As(V) concentrations. The effects of endophyte inoculation on Arabidopsis growth varied by strain and As(V) concentration, and PD9R had positive effect on plants exposed to low levels of arsenic. Comparative genomic analyses exploring the EPS synthesis and arsenic resistance mechanisms against other Pseudomonas and Rahnella strains suggest that both strains possess atypical arsenic resistance mechanisms from other plant-associated strains, while the configuration of the EPS synthesis systems appeared to be more broadly distributed among plant- and non-plant-associated strains.}, } @article {pmid37256458, year = {2023}, author = {Malviya, J and Alameri, AA and Al-Janabi, SS and Fawzi, OF and Azzawi, AL and Obaid, RF and Alsudani, AA and Alkhayyat, AS and Gupta, J and Mustafa, YF and Karampoor, S and Mirzaei, R}, title = {Metabolomic profiling of bacterial biofilm: trends, challenges, and an emerging antibiofilm target.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {8}, pages = {212}, pmid = {37256458}, issn = {1573-0972}, mesh = {*Staphylococcus aureus/metabolism ; *Biofilms ; Bacterial Proteins/genetics/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Metabolomics ; Phosphorylation ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/genetics/metabolism ; }, abstract = {Biofilm-related infections substantially contribute to bacterial illnesses, with estimates indicating that at least 80% of such diseases are linked to biofilms. Biofilms exhibit unique metabolic patterns that set them apart from their planktonic counterparts, resulting in significant metabolic reprogramming during biofilm formation. Differential glycolytic enzymes suggest that central metabolic processes are markedly different in biofilms and planktonic cells. The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is highly expressed in Staphylococcus aureus biofilm progenitors, indicating that changes in glycolysis activity play a role in biofilm development. Notably, an important consideration is a correlation between elevated cyclic di-guanylate monophosphate (c-di-GMP) activity and biofilm formation in various bacteria. C-di-GMP plays a critical role in maintaining the persistence of Pseudomonas aeruginosa biofilms by regulating alginate production, a significant biofilm matrix component. Furthermore, it has been demonstrated that S. aureus biofilm development is initiated by several tricarboxylic acid (TCA) intermediates in a FnbA-dependent manner. Finally, Glucose 6-phosphatase (G6P) boosts the phosphorylation of histidine-containing protein (HPr) by increasing the activity of HPr kinase, enhancing its interaction with CcpA, and resulting in biofilm development through polysaccharide intercellular adhesion (PIA) accumulation and icaADBC transcription. Therefore, studying the metabolic changes associated with biofilm development is crucial for understanding the complex mechanisms involved in biofilm formation and identifying potential targets for intervention. Accordingly, this review aims to provide a comprehensive overview of recent advances in metabolomic profiling of biofilms, including emerging trends, prevailing challenges, and the identification of potential targets for anti-biofilm strategies.}, } @article {pmid37256442, year = {2023}, author = {Celebi, D and Aydın, E and Rakici, E and Baser, S and Celebi, O and Taghizadehghalehjoughi, A}, title = {Evaluation of presence of clone ST131 and biofilm formation in ESBL producing and non-producing Escherichia coli strains.}, journal = {Molecular biology reports}, volume = {50}, number = {7}, pages = {5949-5956}, pmid = {37256442}, issn = {1573-4978}, abstract = {OBJECTIVE: Escherichia coli ST131 is a pandemic clone associated with multidrug resistance, starting with beta-lactamase production and fluoroquinolone resistance in the first place, leading to significant systemic infections. Clones that develop due to the frequency of antimicrobial resistance and the rate of spread in our country are important issues that need to be investigated. This study aims to investigate the incidence of ST131which is a "high-risk pandemic clone E. coli" in ESBL-producing and non-ESBL-producing strains, as well as their biofilm-forming abilities and antibiotic resistance rates.

MATERIALS AND METHODS: A total of 86 E. coli isolates were used in the study. Bacterial identifications were performed by conventional and automated methods. The double disc synergy method was used to demonstrate the presence of ESBL. Molecular studies in all E. coli strains were performed by real-time PCR method.

FINDINGS: 86 strains were studied, of which 83.72% were urine, 6.98% were wound, 4.65% were blood, and 2.33% were tracheal aspirate and sputum. 79.07% of these strains were ESBL-positive. 58.1% of the strains were female, whereas 41.9% were male patients, and the average age was 46.2. Out of 86 strains, 38.72% were ST131 positive, the H30 subclone was detected in 27.27% of them, and the H30-Rx subclone was detected in all of the H30 subclone positive strains. The presence of the ESBL resistance gene was detected at the rate of TEM 41.86%, SHV 37.21%, CTX-M 36.04%, and OXA 4.65%. Most commonly SHV gene (54.54%) was seen in ST131 clone-positive samples. Finally, while it was found that 48.83% of the strains formed biofilm by any method, biofilm formation was detected in 69.7% of the samples that were positive for the ST131 clone.

RESULT: Our study can reveal the dramatic prevalence of the ESBL-producing E. coli strains along with the high-risk ST131 clone, the dominance of the H30Rx subclone of this risky clone, as well as the importance of the influence of resistance mechanisms along with resistance and biofilm.}, } @article {pmid37256384, year = {2023}, author = {Raheel, I and Mohammed, AN and Mohamed, AA}, title = {The Efficacy of Bacteriocins Against Biofilm-Producing Bacteria Causing Bovine Clinical Mastitis in Dairy Farms: A New Strategy.}, journal = {Current microbiology}, volume = {80}, number = {7}, pages = {229}, pmid = {37256384}, issn = {1432-0991}, mesh = {Female ; Animals ; Cattle ; Staphylococcus aureus ; *Bacteriocins/pharmacology ; *Staphylococcal Infections/microbiology ; Coagulase/pharmacology ; *Mastitis, Bovine/prevention & control/microbiology ; Farms ; Staphylococcus/genetics ; Biofilms ; Milk/microbiology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Using an alternative bio-product is one of the most promising ways to control bovine mastitis and avoid new intra-mammary infections. The aims of this study were to ascertain the prevalence of biofilm-forming bacteria responsible for causing clinical mastitis in dairy herds and to assess the effectiveness of bacteriocins, produced by Bacillus subtilis, in controlling the growth of these bacteria in the milk of animals. A total of 150 milk samples were collected from cows and buffalos suffering from mastitis and the etiological agents were isolated and identified by the VITEK-2-COMPACT-SYSTEM®. Additionally, the capability of the bacterial isolates to produce biofilms was determined. RT-PCR was used to detect enterotoxin-producing genes (sed and seb), resistance genes (mecA and blaZ), and biofilm-associated genes (icaA and fnbA) in the isolated bacteria. The susceptibility patterns of the bacterial isolates to bacteriocins were assessed using an agar well-diffusion assay. S. aureus was significantly more capable of producing biofilms than coagulase-negative Staphylococcus isolates. S. ubris was the strongest biofilm producer among the Streptococcus species. The sensitivity profiles of the Staphylococcus spp. (S. aureus and coagulase-negative Staphylococcus) and their biofilm producers to bacteriocins were significantly higher (100% and 90%, respectively) at the same concentration. Bacteriocins had a lethal effect on Staphylococci, Streptococci, and biofilm development at a dose of 250 µg/mL. In dairy farms, bacteriocins are a viable alternative treatment for the prevention and control of bovine clinical mastitis.}, } @article {pmid37255442, year = {2023}, author = {Hugonneau-Beaufet, I and Barnier, JP and Thiriet-Rupert, S and Létoffé, S and Mainardi, JL and Ghigo, JM and Beloin, C and Arthur, M}, title = {Characterization of Pseudomonas aeruginosa l,d-Transpeptidases and Evaluation of Their Role in Peptidoglycan Adaptation to Biofilm Growth.}, journal = {Microbiology spectrum}, volume = {}, number = {}, pages = {e0521722}, doi = {10.1128/spectrum.05217-22}, pmid = {37255442}, issn = {2165-0497}, abstract = {Peptidoglycan is an essential component of the bacterial cell envelope that sustains the turgor pressure of the cytoplasm, determines cell shape, and acts as a scaffold for the anchoring of envelope polymers such as lipoproteins. The final cross-linking step of peptidoglycan polymerization is performed by classical d,d-transpeptidases belonging to the penicillin-binding protein (PBP) family and by l,d-transpeptidases (LDTs), which are dispensable for growth in most bacterial species and whose physiological functions remain elusive. In this study, we investigated the contribution of LDTs to cell envelope synthesis in Pseudomonas aeruginosa grown in planktonic and biofilm conditions. We first assigned a function to each of the three P. aeruginosa LDTs by gene inactivation in P. aeruginosa, heterospecific gene expression in Escherichia coli, and, for one of them, direct determination of its enzymatic activity. We found that the three P. aeruginosa LDTs catalyze peptidoglycan cross-linking (LdtPae1), the anchoring of lipoprotein OprI to the peptidoglycan (LdtPae2), and the hydrolysis of the resulting peptidoglycan-OprI amide bond (LdtPae3). Construction of a phylogram revealed that LDTs performing each of these three functions in various species cannot be assigned to distinct evolutionary lineages, in contrast to what has been observed with PBPs. We showed that biofilm, but not planktonic bacteria, displayed an increase proportion of peptidoglycan cross-links formed by LdtPae1 and a greater extent of OprI anchoring to peptidoglycan, which is controlled by LdtPae2 and LdtPae3. Consistently, deletion of each of the ldt genes impaired biofilm formation and potentiated the bactericidal activity of EDTA. These results indicate that LDTs contribute to the stabilization of the bacterial cell envelope and to the adaptation of peptidoglycan metabolism to growth in biofilm. IMPORTANCE Active-site cysteine LDTs form a functionally heterologous family of enzymes that contribute to the biogenesis of the bacterial cell envelope through formation of peptidoglycan cross-links and through the dynamic anchoring of lipoproteins to peptidoglycan. Here, we report the role of three P. aeruginosa LDTs that had not been previously characterized. We show that these enzymes contribute to resistance to the bactericidal activity of EDTA and to the adaptation of cell envelope polymers to conditions that prevail in biofilms. These results indicate that LDTs should be considered putative targets in the development of drug-EDTA associations for the control of biofilm-related infections.}, } @article {pmid37253897, year = {2023}, author = {Ciszek-Lenda, M and Majka, G and Suski, M and Walczewska, M and Górska, S and Golińska, E and Fedor, A and Gamian, A and Olszanecki, R and Strus, M and Marcinkiewicz, J}, title = {Biofilm-forming strains of P. aeruginosa and S. aureus isolated from cystic fibrosis patients differently affect inflammatory phenotype of macrophages.}, journal = {Inflammation research : official journal of the European Histamine Research Society ... [et al.]}, volume = {72}, number = {6}, pages = {1275-1289}, pmid = {37253897}, issn = {1420-908X}, mesh = {Mice ; Animals ; *Cystic Fibrosis ; *Methicillin-Resistant Staphylococcus aureus/metabolism ; Pseudomonas aeruginosa/physiology ; Staphylococcus aureus/metabolism ; Proteomics ; Mice, Inbred C57BL ; Macrophages/metabolism ; Cytokines/metabolism ; Biofilms ; Phenotype ; *Pseudomonas Infections/microbiology ; }, abstract = {OBJECTIVE: Lung cystic fibrosis (CF) is characterized by chronic infections and hyperinflammatory response of neutrophils and macrophages. P. aeruginosa (PA) and S. aureus (MSSA, MRSA) are major pathogens of advanced CF. The main goal of this study was to compare the inflammatory phenotype of murine C57BL/6 macrophages exposed to PA57 with that exposed to MSSA60, both strains isolated from the same patient with severe CF. In the present study, we used C57BL/6 mice sensitive to lung infection with P. aeruginosa.

METHODS: We measured the release of cytokines and the expression of phenotypic markers of murine neutrophils and macrophages exposed to bacterial cells and biofilm components (i.e., EPS) of the selected bacteria. In addition, a quantitative proteomic approach was used for the characterization of proteome-wide changes in macrophages.

RESULTS: Neutrophils stimulated with PA57 and MSSA60 strains produced hyperinflammatory pattern of cytokines. The pro-inflammatory impact of PA57 was significantly higher than that of MSSA60 (IL-6/IL-10 ratio: PA57 = 9.3 vs. MSSA60 = 1.7). Macrophages produced significantly lower amount of cytokines, but showed classical pattern of M1 markers (iNOS-High; arginase-1 and mannose receptor MRC1-Low). Importantly, as evidenced by proteomic analysis, PA57 and PA57-EPS were stronger inducers of M1 macrophage polarization than the MSSA60 counterparts.

CONCLUSIONS: Our study demonstrated that strong biofilm P. aeruginosa strains, CF isolates, are dominant inducers of M1 macrophages, termed biofilm-associated macrophages (BAMs). We suggest that repolarization of detrimental BAMs might be a new therapeutic strategy to ameliorate the airway damage in CF.}, } @article {pmid37253601, year = {2023}, author = {Ketelboeter, LM and Mitra, S and Gyaneshwar, P}, title = {A thiamine transporter is required for biofilm formation by Rhizobium sp. IRBG74.}, journal = {FEMS microbiology letters}, volume = {370}, number = {}, pages = {}, doi = {10.1093/femsle/fnad046}, pmid = {37253601}, issn = {1574-6968}, support = {#1256879//National Science Foundation/ ; //University of Wisconsin-Milwaukee/ ; }, mesh = {*Thiamine/metabolism ; *Rhizobium/genetics ; Plant Roots/microbiology ; Membrane Transport Proteins/genetics/metabolism ; Biofilms ; }, abstract = {Rhizobium sp. IRBG74 is a nitrogen-fixing symbiont of Sesbania cannabina and a growth-promoting endophyte of rice, thus making it a good model to compare rhizobial interactions with legumes and cereals. In this report, we show that Rhizobium sp. IRBG74 forms biofilms on the roots of S. cannabina and rice. A mutant defective in biofilm formation was identified by screening a transposon mutant library. The transposon insertion was in thiQ, part of the thiBPQ operon that encodes the components of a thiamine/thiamine pyrophosphate ABC transporter. Complementation with thiBPQ partially restored biofilm formation. Addition of thiamine in growth media led to repression of thiC expression in the wild-type strain but not in the thiQ mutant. These results suggest that thiBPQ is involved in thiamine/TPP transport in Rhizobium sp. IRBG74. Using a GUS reporter, we show that the expression of thiC is significantly higher in biofilm as compared to cells in planktonic growth. Based on these results, we propose that Rhizobium sp. IRBG74 is thiamine-limited and requires thiamine transport for efficient biofilm formation and plant colonization. Thiamine synthesis in aerobic bacteria such as Rhizobium requires O2 and thus could be inhibited in the microaerobic/anaerobic conditions in biofilms.}, } @article {pmid37252226, year = {2023}, author = {Louis, M and Tahrioui, A and Lendon, CJ and Clamens, T and Leprince, J and Lefranc, B and Kipnis, E and Grandjean, T and Bouffartigues, E and Barreau, M and Defontaine, F and Cornelis, P and Feuilloley, MGJ and Harmer, NJ and Chevalier, S and Lesouhaitier, O}, title = {The natriuretic peptide receptor agonist osteocrin disperses Pseudomonas aeruginosa biofilm.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100131}, pmid = {37252226}, issn = {2590-2075}, abstract = {Biofilms are highly tolerant to antimicrobials and host immune defense, enabling pathogens to thrive in hostile environments. The diversity of microbial biofilm infections requires alternative and complex treatment strategies. In a previous work we demonstrated that the human Atrial Natriuretic Peptide (hANP) displays a strong anti-biofilm activity toward Pseudomonas aeruginosa and that the binding of hANP by the AmiC protein supports this effect. This AmiC sensor has been identified as an analog of the human natriuretic peptide receptor subtype C (h-NPRC). In the present study, we evaluated the anti-biofilm activity of the h-NPRC agonist, osteocrin (OSTN), a hormone that displays a strong affinity for the AmiC sensor at least in vitro. Using molecular docking, we identified a pocket in the AmiC sensor that OSTN reproducibly docks into, suggesting that OSTN might possess an anti-biofilm activity as well as hANP. This hypothesis was validated since we observed that OSTN dispersed established biofilm of P. aeruginosa PA14 strain at the same concentrations as hANP. However, the OSTN dispersal effect is less marked than that observed for the hANP (-61% versus -73%). We demonstrated that the co-exposure of P. aeruginosa preformed biofilm to hANP and OSTN induced a biofilm dispersion with a similar effect to that observed with hANP alone suggesting a similar mechanism of action of these two peptides. This was confirmed by the observation that OSTN anti-biofilm activity requires the activation of the complex composed by the sensor AmiC and the regulator AmiR of the ami pathway. Using a panel of both P. aeruginosa laboratory reference strains and clinical isolates, we observed that the OSTN capacity to disperse established biofilms is highly variable from one strain to another. Taken together, these results show that similarly to the hANP hormone, OSTN has a strong potential to be used as a tool to disperse P. aeruginosa biofilms.}, } @article {pmid37252093, year = {2023}, author = {Hayet, S and Ghrayeb, M and Azulay, DN and Shpilt, Z and Tshuva, EY and Chai, L}, title = {Titanium complexes affect Bacillus subtilis biofilm formation.}, journal = {RSC medicinal chemistry}, volume = {14}, number = {5}, pages = {983-991}, pmid = {37252093}, issn = {2632-8682}, abstract = {Biofilms are surface or interface-associated communities of bacterial cells, embedded in a self-secreted extracellular matrix (ECM). Cells in biofilms are 100-1000 times more resistant to antibiotic treatment relative to planktonic cells due to various reasons, including the ECM acting as a diffusion barrier to antibiotic molecules, the presence of persister cells that divide slowly and are less susceptible to cell-wall targeting drugs, and the activation of efflux pumps in response to antibiotic stress. In this study we tested the effect of two titanium(iv) complexes that have been previously reported as potent and non-toxic anticancer chemotherapeutic agents on Bacillus subtilis cells in culture and in biofilm forming conditions. The Ti(iv) complexes tested, a hexacoordinate diaminobis(phenolato)-bis(alkoxo) complex (phenolaTi) and a bis(isopropoxo) complex of a diaminobis(phenolato) "salan"-type ligand (salanTi), did not affect the growth rate of cells in shaken cultures, however they did affect biofilm formation. Surprisingly, while phenolaTi inhibited biofilm formation, the presence of salanTi induced the formation of more mechanically robust biofilms. Optical microscopy images of biofilm samples in the absence and presence of Ti(iv) complexes suggest that Ti(iv) complexes affect cell-cell and/or cell-matrix adhesion, and that these are interfered with phenolaTi and enhanced by salanTi. Our results highlight the possible effect of Ti(iv) complexes on bacterial biofilms, which is gaining interest in light of the emerging relations between bacteria and cancerous tumors.}, } @article {pmid37250376, year = {2023}, author = {Redman, RM and Maughan, TD and Smith, CB and Crossno, PF and Granger, DL}, title = {Development of multidrug-resistant Mycobacterium tuberculosis in the biofilm of a peritoneal-venous shunt.}, journal = {IDCases}, volume = {32}, number = {}, pages = {e01801}, pmid = {37250376}, issn = {2214-2509}, abstract = {A patient with ascites received a peritoneal-venous shunt for presumed cirrhosis, however surgical specimens grew Mycobacterium tuberculosis (MTb) sensitive to all anti-tuberculous drugs. Directly-Observed-Therapy (DOT) led to improvement followed by relapse with multidrug resistant MTb (MDRTB). We discuss pathways for selection of MDRTB within mycobacterial biofilm. This case illustrates the potential for development of MDRTB in patients with long-term indwelling catheters. We emphasize catheter removal and if not possible continuing follow-up for symptoms and signs of relapse.}, } @article {pmid37250053, year = {2023}, author = {Zhao, F and Xu, H and Chen, Y and Xiao, J and Zhang, M and Li, Z and Liu, J and Qi, C}, title = {Actinobacillus pleuropneumoniae FliY and YdjN are involved in cysteine/cystine utilization, oxidative resistance, and biofilm formation but are not determinants of virulence.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1169774}, pmid = {37250053}, issn = {1664-302X}, abstract = {INTRODUCTION: Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is a member of Actinobacillus in family Pasteurellaceae. It is the causative agent of porcine pleuropneumonia, which has caused huge economic losses to pig industry over the world. Cysteine is a precursor of many important biomolecules and defense compounds in the cell. However, molecular mechanisms of cysteine transport in A. pleuropneumoniae are unclear.

METHODS: In this study, gene-deleted mutants were generated and investigated, to reveal the roles of potential cysteine/cystine transport proteins FliY and YdjN of A. pleuropneumoniae.

RESULTS: Our results indicated that the growth of A. pleuropneumoniae was not affected after fliY or ydjN single gene deletion, but absence of both FliY and YdjN decreased the growth ability significantly, when cultured in the chemically defined medium (CDM) supplemented with cysteine or cystine as the only sulfur source. A. pleuropneumoniae double deletion mutant ΔfliYΔydjN showed increased sensitivity to oxidative stress. Besides, trans-complementation of YdjN into ΔfliYΔydjN and wild type leads to increased biofilm formation in CDM. However, the virulence of ΔfliYΔydjN was not attenuated in mice or pigs.

DISCUSSION: These findings suggest that A. pleuropneumoniae FliY and YdjN are involved in the cysteine/cystine acquisition, oxidative tolerance, and biofilm formation, but not contribute to the pathogenicity of A. pleuropneumoniae.}, } @article {pmid37249973, year = {2023}, author = {Li, Y and Huang, S and Du, J and Wu, M and Huang, X}, title = {Current and prospective therapeutic strategies: tackling Candida albicans and Streptococcus mutans cross-kingdom biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1106231}, pmid = {37249973}, issn = {2235-2988}, mesh = {Child ; Humans ; Child, Preschool ; *Streptococcus mutans ; Candida albicans ; Biofilms ; *Dental Caries ; }, abstract = {Candida albicans (C. albicans) is the most frequent strain associated with cross-kingdom infections in the oral cavity. Clinical evidence shows the co-existence of Streptococcus mutans (S. mutans) and C. albicans in the carious lesions especially in children with early childhood caries (ECC) and demonstrates the close interaction between them. During the interaction, both S. mutans and C. albicans have evolved a complex network of regulatory mechanisms to boost cariogenic virulence and modulate tolerance upon stress changes in the external environment. The intricate relationship and unpredictable consequences pose great therapeutic challenges in clinics, which indicate the demand for de novo emergence of potential antimicrobial therapy with multi-targets or combinatorial therapies. In this article, we present an overview of the clinical significance, and cooperative network of the cross-kingdom interaction between S. mutans and C. albicans. Furthermore, we also summarize the current strategies for targeting cross-kingdom biofilm.}, } @article {pmid37249569, year = {2023}, author = {Su, H and Yan, X and Zhao, Q and Liao, C and Tian, L and Wang, Z and Wan, Y and Li, N and Wang, X}, title = {Layered Design of a Highly Repeatable Electroactive Biofilm for a Standardized Biochemical Oxygen Demand Sensor.}, journal = {ACS sensors}, volume = {8}, number = {6}, pages = {2383-2390}, doi = {10.1021/acssensors.3c00583}, pmid = {37249569}, issn = {2379-3694}, abstract = {Microbial electrochemical sensors are promising to monitor bioavailable organics in real environments, but their application is restricted by the unpredictable performance of the electroactive biofilm (EAB), which is randomly acclimated from environmental microflora. With a long-term stable EAB as a template, we successfully designed EAB (DEAB) by the sequential growth of Geobacter anodireducens and automatched microbes, achieving a reproducible high current than those naturally acclimated from wastewater (NEAB). Pre-inoculation of planktonic aerobes as oxygen bioscavengers was necessary to ensure the colonization of Geobacter in the inner layer, and the abundant Geobacter (50%) in DEAB guaranteed 4 times higher current density with a 15-fold smaller variation among 20 replicates than those of NEAB. The sensor constructed with DEAB exhibited a shorter measuring time and a precise biochemical oxygen demand (BOD) measurement with acetate, real domestic wastewater, and supernatant of anaerobic digestion. Here, we for the first time proposed an applicable strategy to standardize EABs for BOD sensors, which is also crucial to ensure a stable performance of all bioelectrochemical technologies.}, } @article {pmid37247478, year = {2023}, author = {Chen, L and Fang, D and Zhang, J and Xiao, X and Li, N and Li, Y and Wan, M and Mao, C}, title = {Nanomotors-loaded microneedle patches for the treatment of bacterial biofilm-related infections of wound.}, journal = {Journal of colloid and interface science}, volume = {647}, number = {}, pages = {142-151}, doi = {10.1016/j.jcis.2023.05.080}, pmid = {37247478}, issn = {1095-7103}, mesh = {Humans ; *Photochemotherapy/methods ; Drug Delivery Systems/methods ; Phototherapy/methods ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; *Bacterial Infections ; Biofilms ; }, abstract = {The biofilms formed by bacteria at the wound site can effectively protect the bacteria, which greatly weakens the effect of antibiotics. Herein, a microneedle patch for wound treatment is designed, which can effectively penetrate the biofilms in a physical way because of the penetration ability of the microneedles and the motion behavior of the nanomotors, and deliver bacterial quorum sensing inhibitor luteolin (Le) and nanomotors with multiple antibacterial properties within biofilms. Firstly, the nanomotors-loaded microneedle patches are prepared and characterized. The results of in vitro and in vivo experiments show that the microneedle patches have good biosafety and antibacterial properties. Among them, Le can inhibit the growth of biofilms. Further, under near-infrared (NIR) irradiation, the nanomotors loaded with photosensitizer ICG and nitric oxide (NO) donor L-arginine (L-Arg) can move in the biofilms under the double driving effect of photothermal and NO, and can give full play to the multiple anti-biological infection effects of photothermal therapy (PTT), photodynamic therapy (PDT) and NO, and finally realize the effective removal of biofilms and promote wound healing. The intervention of nanomotor technology has brought about a new therapeutic strategy for bacterial biofilm-related infection of wound.}, } @article {pmid37247241, year = {2023}, author = {Brunetti, G and Valentini, E and Berlutti, F and Calvani, P and Raponi, F and Antonelli, G and Romeo, U and Raponi, G}, title = {The effect of the electromagnetic field on metabolic-active bacterial biofilm experimentallyinduced on titanium dental implants.}, journal = {The new microbiologica}, volume = {46}, number = {2}, pages = {202-206}, pmid = {37247241}, issn = {1121-7138}, mesh = {Humans ; *Peri-Implantitis/therapy/microbiology ; Titanium ; *Dental Implants ; Electromagnetic Fields ; Kinetics ; Bacteria ; Biofilms ; }, abstract = {Microbial biofilm is of paramount importance in the development of mucositis or peri-implantitis in patients with dental implants. This study was designed to investigate whether an electromagnetic field at high frequency waves directly applied on 33 titanium implants could remove experimentally-induced Enterococcus faecalis bacterial biofilm. A specially designed device (X-IMPLANT) was used to generate the electromagnetic field, with output power of 8 W, supply frequency (action/pause) 3/2s, and an output frequency of 625±5% kHz in plastic devices containing the biofilm-covered implants immersed in sterile saline. The bacterial biofilm on both treated and untreated control implants was quantitatively measured by phenol red-based Bio-Timer-Assay reagent. The kinetic analysis of the curves showed that the electrical treatment generated by the X-IMPLANT device completely removed the bacterial biofilm after 30 minutes of treatment (p<0.01). Elimination of the biofilm was also confirmed by chromatic observation in the macro-method. Our data seem to indicate that the procedure could be considered for clinical application in peri-implantitis to counteract bacterial biofilm on dental implants.}, } @article {pmid37246932, year = {2023}, author = {Ušjak, D and Novović, K and Ivković, B and Tomić, B and Đorđević, V and Milenković, MT}, title = {Targeting outer membrane protein A (OmpA) - inhibitory effect of 2'-hydroxychalcone derivatives on Acinetobacter baumannii and Candida albicans dual-species biofilm formation.}, journal = {Biofouling}, volume = {39}, number = {3}, pages = {316-326}, doi = {10.1080/08927014.2023.2215693}, pmid = {37246932}, issn = {1029-2454}, mesh = {Candida albicans ; *Acinetobacter baumannii ; *Chalcones/pharmacology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Biofilm production facilitates microbial colonization of wounds and catheters. Acinetobacter baumannii produces high levels of biofilm and causes difficult-to-treat nosocomial infections. Candida albicans is another strong biofilm producer which may facilitate A. baumannii adhesion by providing hyphae-mediated OmpA-binding sites. Here we tested the potential of 2'-hydroxychalcones to inhibit dual-species biofilm production of A. baumannii and Candida spp., and further predicted the mechanism of structure-related difference in activity. The results suggest that 2'-hydroxychalcones exhibit potent activity against Candida spp./A. baumannii dual-species biofilm production. Particularly active was trifluoromethyl-substituted derivative (p-CF3), which decreased C. albicans/A. baumannii biomass produced on vein-indwelling parts of the central venous catheterization set by up to 99%. Further, higher OmpA-binding affinity was also calculated for p-CF3, which together with demonstrated significant ompA-downregulating activity, suggests that superior antibiofilm activity of this chalcone against the tested dual-species community of A. baumannii is mediated through the OmpA.}, } @article {pmid37244492, year = {2023}, author = {Wang, YD and Gong, JS and Guan, YC and Zhao, ZL and Cai, YN and Shan, XF}, title = {OmpR (TCS response regulator) of Aeromonas veronii plays a major role in drug resistance, stress resistance and virulence by regulating biofilm formation.}, journal = {Microbial pathogenesis}, volume = {181}, number = {}, pages = {106176}, doi = {10.1016/j.micpath.2023.106176}, pmid = {37244492}, issn = {1096-1208}, abstract = {Aeromonas veronii (A. veronii), a highly pathogenic bacteria with a wide range of hosts, widely exists in the environment of humans, animals and aquatic animals, and can cause a variety of diseases. In this study, the receptor regulator ompR in the envZ/ompR of two-component system was selected to construct a mutant strain (Δ ompR) and a complement strain (C-ompR) to explore the regulatory effect of ompR on the biological characteristics and virulence of TH0426. The results showed that the ability of biofilm formation and osmotic stress of TH0426 were significantly reduced (P < 0.001), the resistance to ceftriaxone and neomycin were slightly down-regulate when the ompR gene was deleted. At the same time, animal pathogenicity experiments showed that the virulence of TH0426 was significantly down-regulated (P < 0.001). These results indicated that ompR gene regulates the biofilm formation of TH0426, and regulates some biological characteristics of TH0426, including drug sensitivity, resistance to osmotic stress, and also affects its virulence.}, } @article {pmid37244336, year = {2023}, author = {Zhang, X and Qu, Q and Yang, A and Wang, J and Cheng, W and Zhou, A and Xiong, R and Huang, C}, title = {Prussian blue composite microswimmer based on alginate-chitosan for biofilm removal.}, journal = {International journal of biological macromolecules}, volume = {242}, number = {Pt 4}, pages = {124963}, doi = {10.1016/j.ijbiomac.2023.124963}, pmid = {37244336}, issn = {1879-0003}, mesh = {*Chitosan/pharmacology/chemistry ; Alginates ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; }, abstract = {Bacterial infections pose a serious threat to public health, causing worldwide morbidity and about 80 % of bacterial infections are related to biofilm. Removing biofilm without antibiotics remains an interdisciplinary challenge. To solve this problem, we presented a dual-power driven antibiofilm system Prussian blue composite microswimmers based on alginate-chitosan, which designed into an asymmetric structure to achieve self-driven in the fuel solution and magnetic field. Prussian blue embedded in the microswimmers given it the ability to convert light and heat, catalyze Fenton reaction, and produce bubbles and reactive oxygen species. Moreover, with the addition of Fe3O4, the microswimmers could move in group under external magnetic field. The composite microswimmers displayed excellent antibacterial activity against S. aureus biofilm with an efficiency as high as 86.94 %. It is worth mentioning that the microswimmers were fabricated with device-simple and low-cost gas-shearing method. This system integrating physical destruction, chemical damage such chemodynamic therapy and photothermal therapy, and finally kill the plankton bacteria embedded in biofilm. This approach may cause an autonomous, multifunctional antibiofilm platform to promote the present most areas with harmful biofilm difficult to locate the surface for removal.}, } @article {pmid37244228, year = {2023}, author = {Manville, E and Kaya, EC and Yucel, U and Boyle, D and Trinetta, V}, title = {Evaluation of Listeria monocytogenes biofilms attachment and formation on different surfaces using a CDC biofilm reactor.}, journal = {International journal of food microbiology}, volume = {399}, number = {}, pages = {110251}, doi = {10.1016/j.ijfoodmicro.2023.110251}, pmid = {37244228}, issn = {1879-3460}, mesh = {United States ; *Listeria monocytogenes ; Food Microbiology ; Biofilms ; Food Contamination/prevention & control/analysis ; Centers for Disease Control and Prevention, U.S. ; Stainless Steel/analysis ; }, abstract = {Listeria monocytogenes can adapt, persist, and form biofilms on food premises surfaces, representing a challenge for food safety, since they led to disease transmission, food contamination and spoilage during production. Physical interventions (scrubbing and wiping) can help controlling formation, nevertheless when biofilms are formed, they are usually very resistant to current control strategies used in the food industry. Biofilm attachment and formation is influenced by environment characteristics, substrate properties and microbial motility. The purpose of this study was to evaluate the ability of L. monocytogenes to attach and form biofilms on different surfaces (wood, nylon, and polycarbonate) representative of the materials used during produce harvesting and storage. Multi-strain L. monocytogenes biofilms were grown in a CDC Biofilm reactor at 20 ± 2 °C up to 96-h and characterized for: a) attachment strength by enumerating cells after rinsing; b) hydrophobicity and interfacial tension by contact angle measurements; c) biofilm architecture by Laser Scanning Confocal Microscopy. All experiments were done in triplicate. Material, incubation, and solvent significantly affected the hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). The type of material and incubation time significantly influenced hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). Highest contact angle and lowest interfacial tension were observed on polycarbonate coupons. The data presented contributes to understanding Listeria biofilms grow on different surfaces commonly used in produce harvesting and storage. The data obtained in this study can be used when evaluating intervention strategies to control this pathogen in food premises.}, } @article {pmid37243862, year = {2023}, author = {Misra, T and Tare, M and Jha, PN}, title = {Characterization of functional amyloid curli in biofilm formation of an environmental isolate Enterobacter cloacae SBP-8.}, journal = {Antonie van Leeuwenhoek}, volume = {}, number = {}, pages = {}, pmid = {37243862}, issn = {1572-9699}, abstract = {The biofilm formation by bacteria is a complex process that is strongly mediated by various genetic and environmental factors. Biofilms contribute to disease infestation, especially in chronic infections. It is, therefore important to understand the factors affecting biofilm formation. This study reports the role of a functional amyloid curli in biofilm formation at various abiotic surfaces, including medical devices, by an environmental isolate of Enterobacter cloacae (SBP-8) which has been known for its pathogenic potential. A knockout mutant of csgA, the gene encoding the major structural unit of curli, was created to study the effect of curli on biofilm formation by E. cloacae SBP-8. Our findings confirm the production of curli at 25 °C and 37 °C in the wild-type strain. We further investigated the role of curli in the attachment of E. cloacae SBP-8 to glass, enteral feeding tube, and foley latex catheter. Contrary to the previous studies reporting the curli production below 30 °C in the majority of biofilm-forming bacterial species, we observed its production in E. cloacae SBP-8 at 37 °C. The formation of more intense biofilm in wild-type strain on various surfaces compared to curli-deficient strain (ΔcsgA) at both 25 °C and 37 °C suggested a prominent role of curli in biofilm formation. Further, electron and confocal microscopy studies demonstrated the formation of diffused monolayers of microbial cells on the abiotic surfaces by ΔcsgA strain as compared to the thick biofilm by respective wild-type strain, indicating the involvement of curli in biofilm formation by E. cloacae SBP-8. Overall, our findings provide insight into biofilm formation mediated by curli in E. cloacae SBP-8. Further, we show that it can be expressed at a physiological temperature on all surfaces, thereby indicating the potential role of curli in pathogenesis.}, } @article {pmid37243294, year = {2023}, author = {Jin, X and Sun, X and Wang, Z and Dou, J and Lin, Z and Lu, Q and Zhang, T and Wen, G and Shao, H and Cheng, G and Luo, Q}, title = {Virulent Phage vB_EfaS_WH1 Removes Enterococcus faecalis Biofilm and Inhibits Its Growth on the Surface of Chicken Meat.}, journal = {Viruses}, volume = {15}, number = {5}, pages = {}, pmid = {37243294}, issn = {1999-4915}, mesh = {Humans ; Animals ; *Bacteriophages/genetics ; Enterococcus faecalis ; Chickens/genetics ; Phylogeny ; Biofilms ; Genome, Viral ; Meat ; }, abstract = {Enterococcus faecalis is a potential animal and human pathogen. Improper use of antibiotics encourages resistance. Bacteriophages and their derivatives are promising for treating drug-resistant bacterial infections. In this study, phylogenetic and electron microscopy analyses of phage vB_EfaS_WH1 (WH1) isolated from chicken feces revealed it to be a novel phage in the family Siphoviridae. WH1 showed good pH stability (4-11), temperature tolerance (4-60 °C), and broad E. faecalis host range (60% of isolates). Genome sequencing revealed a 56,357 bp double-stranded DNA genome with a G+C content of 39.21%. WH1 effectively destroyed E. faecalis EF01 biofilms, even at low concentrations. When WH1 was applied at 1 × 10[5] to 1 × 10[9] PFU/g to chicken breast samples stored at 4 °C, surface growing E. faecalis were appreciably eradicated after 24 h. The phage WH1 showed good antibacterial activity, which could be used as a potential biocontrol agent to reduce the formation of E. faecalis biofilm, and could also be used as an alternative for the control of E. faecalis in chicken products.}, } @article {pmid37242661, year = {2023}, author = {Butrungrod, W and Chaiyasut, C and Makhamrueang, N and Peerajan, S and Chaiyana, W and Sirilun, S}, title = {Postbiotic Metabolite of Lactiplantibacillus plantarum PD18 against Periodontal Pathogens and Their Virulence Markers in Biofilm Formation.}, journal = {Pharmaceutics}, volume = {15}, number = {5}, pages = {}, pmid = {37242661}, issn = {1999-4923}, support = {PHD60I0021//Thailand Research Fund (TRF), and Research and Researchers for Industry (RRi)/ ; }, abstract = {Alternative methods to reduce infectious diseases caused by bacterial pathogens and their virulence factors, biofilm formations, have arisen to reduce the pressure on existing or currently developed disinfectants and antimicrobial agents. The current strategies for reducing the severity of periodontal pathogen-caused disease by using beneficial bacteria and their metabolites are highly desirable. Probiotic strains of lactobacilli related to foods from Thai-fermented foods were selected and their postbiotic metabolites (PM) were isolated with inhibitory activity on periodontal pathogens and their biofilm formation. The PM from Lactiplantibacillus plantarum PD18 (PD18 PM) with the highest antagonistic effect against Streptococcus mutans, Porphyromonas gingivalis, Tannerella forsythia and Prevotella loescheii was selected from 139 Lactobacillus isolates. The minimal inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) values of PD18 PM against the pathogens ranged from 1:2 to 1:4. The PD18 PM demonstrated the ability to prevent the biofilm formation of S. mutans and P. gingivalis by showing a significant reduction in viable cells, high percentages of biofilm inhibition at 92.95 and 89.68%, and the highest effective contact times at 5 and 0.5 min, respectively. L. plantarum PD18 PM showed potential as a promising natural adjunctive agent to inhibit periodontal pathogens and their biofilms.}, } @article {pmid37242644, year = {2023}, author = {Costa-Orlandi, CB and Bila, NM and Bonatti, JLC and Vaso, CO and Santos, MB and Polaquini, CR and Santoni Biasioli, MM and Herculano, RD and Regasini, LO and Fusco-Almeida, AM and Mendes-Giannini, MJS}, title = {Membranolytic Activity Profile of Nonyl 3,4-Dihydroxybenzoate: A New Anti-Biofilm Compound for the Treatment of Dermatophytosis.}, journal = {Pharmaceutics}, volume = {15}, number = {5}, pages = {}, pmid = {37242644}, issn = {1999-4923}, support = {2017/18388-6 (C.B.C.-O.), 2019/22188-8 (N.M.B.), 2020/15586-4 (C.O.V.), and 2018/02785-9 (M.J.S.M.-G.)//São Paulo Research Foundation/ ; finance code 001, 88887.500765/2020-00 (C.O.V.)//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 142049/2019-0 (N.M.B), 105072/2018-4 (J.L.C.B.) and [134559/2018-5 (C.O.V.)]//National Council for Scientific and Technological Development/ ; IBE150/2017 (N.M.B.)//Instituto de Bolsa de Estudos (I.B.E.) - Moçambique/ ; PDI-UNESP-00//Pró-Reitoria de Pós-Graduação (P.R.O.P.G.)/ ; }, abstract = {The ability of dermatophytes to live in communities and resist antifungal drugs may explain treatment recurrence, especially in onychomycosis. Therefore, new molecules with reduced toxicity that target dermatophyte biofilms should be investigated. This study evaluated nonyl 3,4-dihydroxybenzoate (nonyl) susceptibility and mechanism of action on planktonic cells and biofilms of T. rubrum and T. mentagrophytes. Metabolic activities, ergosterol, and reactive oxygen species (ROS) were quantified, and the expression of genes encoding ergosterol was determined by real-time PCR. The effects on the biofilm structure were visualized using confocal electron microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). T. rubrum and T. mentagrophytes biofilms were susceptible to nonyl and resistant to fluconazole, griseofulvin (all strains), and terbinafine (two strains). The SEM results revealed that nonyl groups seriously damaged the biofilms, whereas synthetic drugs caused little or no damage and, in some cases, stimulated the development of resistance structures. Confocal microscopy showed a drastic reduction in biofilm thickness, and transmission electron microscopy results indicated that the compound promoted the derangement and formation of pores in the plasma membrane. Biochemical and molecular assays indicated that fungal membrane ergosterol is a nonyl target. These findings show that nonyl 3,4-dihydroxybenzoate is a promising antifungal compound.}, } @article {pmid37242643, year = {2023}, author = {Almasri, D and Dahman, Y}, title = {Prosthetic Joint Infections: Biofilm Formation, Management, and the Potential of Mesoporous Bioactive Glass as a New Treatment Option.}, journal = {Pharmaceutics}, volume = {15}, number = {5}, pages = {}, pmid = {37242643}, issn = {1999-4923}, abstract = {Infection of prosthetic joints is one of the biggest challenges to a successful replacement of the joint after a total joint arthroplasty. Such infections are caused by bacterial colonies that are difficult to treat by systemic delivery of antibiotics. Local delivery of antibiotics can prove to be the solution to such a devastating outcome that impacts patients' health and ability to regain function in their joints as well as costs the healthcare system millions of dollars every year. This review will discuss prosthetic joint infections in detail with a focus on the development, management, and diagnosis of the infections. Surgeons often opt to use polymethacrylate cement locally to deliver antibiotics; however, due to the rapid release of antibiotics, non-biodegradability, and high chance of reinfection, the search for alternatives is in high demand. One of the most researched alternatives to current treatments is the use of biodegradable and highly compatible bioactive glass. The novelty of this review lies in its focus on mesoporous bioactive glass as a potential alternative to current treatments for prosthetic joint infection. Mesoporous bioactive glass is the focus of this review because it has a higher capacity to deliver biomolecules, stimulate bone growth, and treat infections after prosthetic joint replacement surgeries. The review also examines different synthesis methods, compositions, and properties of mesoporous bioactive glass, highlighting its potential as a biomaterial for the treatment of joint infections.}, } @article {pmid37242528, year = {2023}, author = {Abudalu, M and Aqawi, M and Sionov, RV and Friedman, M and Gati, I and Munz, Y and Ohana, G and Steinberg, D}, title = {Polyglactin 910 Meshes Coated with Sustained-Release Cannabigerol Varnish Inhibit Staphylococcus aureus Biofilm Formation and Macrophage Cytokine Secretion: An In Vitro Study.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {5}, pages = {}, pmid = {37242528}, issn = {1424-8247}, support = {0//STEP-GTP/ ; }, abstract = {Synthetic surgical meshes are commonly used in abdominal wall reconstruction surgeries to strengthen a weak abdominal wall. Common mesh-related complications include local infection and inflammatory processes. Because cannabigerol (CBG) has both antibacterial and anti-inflammatory properties, we proposed that coating VICRYL (polyglactin 910) mesh with a sustained-release varnish (SRV) containing CBG would prevent these complications. We used an in vitro infection model with Staphylococcus aureus and an in vitro inflammation model of lipopolysaccharide (LPS)-stimulated macrophages. Meshes coated with either SRV-placebo or SRV-CBG were exposed daily to S. aureus in tryptic soy medium (TSB) or macrophage Dulbecco's modified eagle medium (DMEM). Bacterial growth and biofilm formation in the environment and on the meshes were assessed by changes in optical density, bacterial ATP content, metabolic activity, crystal violet staining, spinning disk confocal microscopy (SDCM), and high-resolution scanning electron microscopy (HR-SEM). The anti-inflammatory effect of the culture medium that was exposed daily to the coated meshes was analyzed by measuring the release of the cytokines IL-6 and IL-10 from LPS-stimulated RAW 264.7 macrophages with appropriate ELISA kits. Additionally, a cytotoxicity assay was performed on Vero epithelial cell lines. We observed that compared with SRV-placebo, the segments coated with SRV-CBG inhibited the bacterial growth of S. aureus in the mesh environment for 9 days by 86 ± 4% and prevented biofilm formation and metabolic activity in the surroundings for 9 days, with respective 70 ± 2% and 95 ± 0.2% reductions. The culture medium that was incubated with the SRV-CBG-coated mesh inhibited LPS-induced secretion of IL-6 and IL-10 from the RAW 264.7 macrophages for up to 6 days without affecting macrophage viability. A partial anti-inflammatory effect was also observed with SRV-placebo. The conditioned culture medium was not toxic to Vero epithelial cells, which had an IC50 of 25 µg/mL for CBG. In conclusion, our data indicate a potential role of coating VICRYL mesh with SRV-CBG in preventing infection and inflammation in the initial period after surgery.}, } @article {pmid37242523, year = {2023}, author = {Leesombun, A and Sungpradit, S and Bangphoomi, N and Thongjuy, O and Wechusdorn, J and Riengvirodkij, S and Wannawong, J and Boonmasawai, S}, title = {Effects of Piper betle Extracts against Biofilm Formation by Methicillin-Resistant Staphylococcus pseudintermedius Isolated from Dogs.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {5}, pages = {}, pmid = {37242523}, issn = {1424-8247}, support = {Mahidol University-2562//Mahidol University/ ; }, abstract = {Emergence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolated from dogs with cutaneous and wound infections has significantly impacted veterinary medicine. This study aimed to isolate S. pseudintermedius from canine pyoderma and investigate the effects of ethanolic extracts of Piper betle (PB), P. sarmentosum (PS), and P. nigrum (PN) on the bacterial growth and biofilm formation of S. pseudintermedius and MRSP. Of the isolated 152 isolates, 53 were identified as S. pseudintermedius using polymerase chain reaction, and 10 isolates (6.58%) were identified as MRSP based on the presence of mecA. Based on phenotype, 90% of MRSPs were multidrug-resistant. All MRSP had moderate (10%, 1/10) and strong (90%, 9/10) biofilm production ability. PB extracts were the most effective in inhibiting planktonic cells, and the minimum inhibitory concentration at which ≥50% of the isolates were inhibited (MIC50) was 256 µg/mL (256-1024 µg/mL) for S. pseudintermedius isolates and 512 µg/mL (256-1024 µg/mL) for MRSP isolates. The MIC90 for S. pseudintermedius and MRSP was 512 µg/mL. In XTT assay, PB at 4× MIC showed an inhibition rate of 39.66-68.90% and 45.58-59.13% for S. pseudintermedius and MRSP, respectively, in inhibiting biofilm formation. For PB at 8× MIC, the inhibition rates for S. pseudintermedius and MRSP were 50.74-81.66% and 59.57-78.33%, respectively. Further, 18 compounds were identified in PB using gas chromatography-mass spectrometry, and hydroxychavicol (36.02%) was the major constituent. These results indicated that PB could inhibit bacteria growth of and biofilm formation by S. pseudintermedius and MRSP isolated from canine pyoderma in a concentration-dependent manner. Therefore, PB is a potential candidate for the treatment of MRSP infection and biofilm formation in veterinary medicine.}, } @article {pmid37241392, year = {2023}, author = {Ścibik, Ł and Ochońska, D and Gołda-Cępa, M and Kwiecień, K and Pamuła, E and Kotarba, A and Brzychczy-Włoch, M}, title = {Sonochemical Deposition of Gentamicin Nanoparticles at the PCV Tracheostomy Tube Surface Limiting Bacterial Biofilm Formation.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {10}, pages = {}, pmid = {37241392}, issn = {1996-1944}, support = {POWR.03.02.00-00-I013/16//InterDokMed/ ; }, abstract = {BACKGROUND: The use of nanotechnology in the production of medical equipment has opened new possibilities to fight bacterial biofilm developing on their surfaces, which can cause infectious complications. In this study, we decided to use gentamicin nanoparticles. An ultrasonic technique was used for their synthesis and immediate deposition onto the surface of tracheostomy tubes, and their effect on bacterial biofilm formation was evaluated.

METHODS: Polyvinyl chloride was functionalized using oxygen plasma followed by sonochemical formation and the embedment of gentamicin nanoparticles. The resulting surfaces were characterized with the use of AFM, WCA, NTA, FTIR and evaluated for cytotoxicity with the use of A549 cell line and for bacterial adhesion using reference strains of S. aureus (ATCC[®] 25923™) and E. coli (ATCC[®] 25922™).

RESULTS: The use of gentamicin nanoparticles significantly reduced the adhesion of bacterial colonies on the surface of the tracheostomy tube for S. aureus from 6 × 10[5] CFU/mL to 5 × 10[3] CFU/mL and for E. coli from 1.655 × 10[5] CFU/mL to 2 × 10[1] CFU/mL, and the functionalized surfaces did not show a cytotoxic effect on A549 cells (ATTC CCL 185).

CONCLUSIONS: The use of gentamicin nanoparticles on the polyvinyl chloride surface may be an additional supporting method for patients after tracheostomy in order to prevent the colonization of the biomaterial by potentially pathogenic microorganisms.}, } @article {pmid37241277, year = {2023}, author = {Vladkova, TG and Staneva, AD and Avramova, IA and Ivanova, IA and Gospodinova, DN}, title = {Fucoidan-Containing, Low-Adhesive Siloxane Coatings for Medical Applications: Inhibition of Bacterial Growth and Biofilm Development.}, journal = {Materials (Basel, Switzerland)}, volume = {16}, number = {10}, pages = {}, pmid = {37241277}, issn = {1996-1944}, support = {KP-06-H27/17.12.2017.//Bulgarian National Scientific Fund/ ; }, abstract = {The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a non-toxic, natural, biologically active substance, such as fucoidan, to inhibit bacterial growth on similar medical coatings. The fucoidan amount was varied, and its impact on the bioadhesion-influencing surface characteristics, as well as on bacterial cell growth, was investigated. The inclusion of up to 3-4 wt.% brown algae-derived fucoidan in the coatings increases their inhibitory effect, more significantly on the Gram-positive bacterium S. aureus than on the Gram-negative bacterium Escherichia coli. The biological activity of the studied siloxane coatings was ascribed to the formation of a low-adhesive, biologically active surface top layer consisting of siloxane oil and dispersed water-soluble fucoidan particles. This is the first report on the antibacterial activity of fucoidan-containing medical siloxane coatings. The experimental results give reason to expect that relevantly selected, natural biologically active substances can be efficient in the non-toxic control of bacterial growth on medical devices and, as a result, medical device-associated infections.}, } @article {pmid37240199, year = {2023}, author = {Ma, X and Liu, H and Liu, Z and Wang, Y and Zhong, Z and Peng, G and Gu, Y}, title = {Trichosporon asahii PLA2 Gene Enhances Drug Resistance to Azoles by Improving Drug Efflux and Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {24}, number = {10}, pages = {}, pmid = {37240199}, issn = {1422-0067}, support = {SCCXTD-2022-13//the Sichuan Beef Cattle Innovation team of the National Modern Agricultural Industry Tech-nology System/ ; }, mesh = {Humans ; *Azoles/pharmacology ; Antifungal Agents/pharmacology ; *Trichosporon/genetics ; Drug Resistance, Fungal/genetics ; Biofilms ; }, abstract = {Trichosporon asahii is an opportunistic pathogen that can cause severe or even fatal infections in patients with low immune function. sPLA2 plays different roles in different fungi and is also related to fungal drug resistance. However, the mechanism underlying its drug resistance to azoles has not yet been reported in T. asahii. Therefore, we investigated the drug resistance of T. asahii PLA2 (TaPLA2) by constructing overexpressing mutant strains (TaPLA2[OE]). TaPLA2[OE] was generated by homologous recombination of the recombinant vector pEGFP-N1-TaPLA2, induced by the CMV promoter, with Agrobacterium tumefaciens. The structure of the protein was found to be typical of sPLA2, and it belongs to the phospholipase A2_3 superfamily. TaPLA2[OE] enhanced antifungal drug resistance by upregulating the expression of effector genes and increasing the number of arthrospores to promote biofilm formation. TaPLA2[OE] was highly sensitive to sodium dodecyl sulfate and Congo red, indicating impaired cell wall integrity due to downregulation of chitin synthesis or degradation genes, which can indirectly affect fungal resistance. In conclusion, TaPLA2 overexpression enhanced the resistance to azoles of T. asahii by enhancing drug efflux and biofilm formation and upregulating HOG-MAPK pathway genes; therefore, it has promising research prospects.}, } @article {pmid37240055, year = {2023}, author = {Chung, J and Eisha, S and Park, S and Morris, AJ and Martin, I}, title = {How Three Self-Secreted Biofilm Exopolysaccharides of Pseudomonas aeruginosa, Psl, Pel, and Alginate, Can Each Be Exploited for Antibiotic Adjuvant Effects in Cystic Fibrosis Lung Infection.}, journal = {International journal of molecular sciences}, volume = {24}, number = {10}, pages = {}, pmid = {37240055}, issn = {1422-0067}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology/therapeutic use/metabolism ; Pseudomonas aeruginosa/metabolism ; *Cystic Fibrosis/drug therapy ; Alginates/metabolism ; Biofilms ; Adjuvants, Immunologic/therapeutic use ; Adjuvants, Pharmaceutic/therapeutic use ; Lung ; *Pseudomonas Infections/drug therapy ; }, abstract = {In cystic fibrosis (CF), pulmonary infection with Pseudomonas aeruginosa is a cause of increased morbidity and mortality, especially in patients for whom infection becomes chronic and there is reliance on long-term suppressive therapies. Current antimicrobials, though varied mechanistically and by mode of delivery, are inadequate not only due to their failure to eradicate infection but also because they do not halt the progression of lung function decline over time. One of the reasons for this failure is thought to be the biofilm mode of growth of P. aeruginosa, wherein self-secreted exopolysaccharides (EPSs) provide physical protection against antibiotics and an array of niches with resulting metabolic and phenotypic heterogeneity. The three biofilm-associated EPSs secreted by P. aeruginosa (alginate, Psl, and Pel) are each under investigation and are being exploited in ways that potentiate antibiotics. In this review, we describe the development and structure of P. aeruginosa biofilms before examining each EPS as a potential therapeutic target for combating pulmonary infection with P. aeruginosa in CF, with a particular focus on the current evidence for these emerging therapies and barriers to bringing these therapies into clinic.}, } @article {pmid37239957, year = {2023}, author = {Su, X and Cui, H and Zhang, W}, title = {Copiotrophy in a Marine-Biofilm-Derived Roseobacteraceae Bacterium Can Be Supported by Amino Acid Metabolism and Thiosulfate Oxidation.}, journal = {International journal of molecular sciences}, volume = {24}, number = {10}, pages = {}, pmid = {37239957}, issn = {1422-0067}, mesh = {*Thiosulfates/metabolism ; Oxidation-Reduction ; *Sulfur Compounds/metabolism ; Amino Acids/metabolism ; Carbon/metabolism ; }, abstract = {Copiotrophic bacteria that respond rapidly to nutrient availability, particularly high concentrations of carbon sources, play indispensable roles in marine carbon cycling. However, the molecular and metabolic mechanisms governing their response to carbon concentration gradients are not well understood. Here, we focused on a new member of the family Roseobacteraceae isolated from coastal marine biofilms and explored the growth strategy at different carbon concentrations. When cultured in a carbon-rich medium, the bacterium grew to significantly higher cell densities than Ruegeria pomeroyi DSS-3, although there was no difference when cultured in media with reduced carbon. Genomic analysis showed that the bacterium utilized various pathways involved in biofilm formation, amino acid metabolism, and energy production via the oxidation of inorganic sulfur compounds. Transcriptomic analysis indicated that 28.4% of genes were regulated by carbon concentration, with increased carbon concentration inducing the expression of key enzymes in the EMP, ED, PP, and TCA cycles, genes responsible for the transformation of amino acids into TCA intermediates, as well as the sox genes for thiosulfate oxidation. Metabolomics showed that amino acid metabolism was enhanced and preferred in the presence of a high carbon concentration. Mutation of the sox genes decreased cell proton motive force when grown with amino acids and thiosulfate. In conclusion, we propose that copiotrophy in this Roseobacteraceae bacterium can be supported by amino acid metabolism and thiosulfate oxidation.}, } @article {pmid37237796, year = {2023}, author = {Arumugam, M and Manikandan, DB and Marimuthu, SK and Muthusamy, G and Kari, ZA and Téllez-Isaías, G and Ramasamy, T}, title = {Evaluating Biofilm Inhibitory Potential in Fish Pathogen, Aeromonas hydrophila by Agricultural Waste Extracts and Assessment of Aerolysin Inhibitors Using In Silico Approach.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {5}, pages = {}, pmid = {37237796}, issn = {2079-6382}, support = {2019-69012-29905//USDA-NIFA Sustainable Agriculture Systems/ ; }, abstract = {Aeromonas hydrophila, an opportunistic bacteria, causes several devastating diseases in humans and animals, particularly aquatic species. Antibiotics have been constrained by the rise of antibiotic resistance caused by drug overuse. Therefore, new strategies are required to prevent appropriate antibiotic inability from antibiotic-resistant strains. Aerolysin is essential for A. hydrophila pathogenesis and has been proposed as a potential target for inventing drugs with anti-virulence properties. It is a unique method of disease prevention in fish to block the quorum-sensing mechanism of A. hydrophila. In SEM analysis, the crude solvent extracts of both groundnut shells and black gram pods exhibited a reduction of aerolysin formation and biofilm matrix formation by blocking the QS in A. hydrophila. Morphological changes were identified in the extracts treated bacterial cells. Furthermore, in previous studies, 34 ligands were identified with potential antibacterial metabolites from agricultural wastes, groundnut shells, and black gram pods using a literature survey. Twelve potent metabolites showed interactions between aerolysin and metabolites during molecular docking analysis, in that H-Pyran-4-one-2,3 dihydro-3,5 dihydroxy-6-methyl (-5.3 kcal/mol) and 2-Hexyldecanoic acid (-5.2 kcal/mol) showed promising results with potential hydrogen bond interactions with aerolysin. These metabolites showed a better binding affinity with aerolysin for 100 ns in molecular simulation dynamics. These findings point to a novel strategy for developing drugs using metabolites from agricultural wastes that may be feasible pharmacological solutions for treating A. hydrophila infections for the betterment of aquaculture.}, } @article {pmid37237778, year = {2023}, author = {Makhlouf, Z and Ali, AA and Al-Sayah, MH}, title = {Liposomes-Based Drug Delivery Systems of Anti-Biofilm Agents to Combat Bacterial Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {5}, pages = {}, pmid = {37237778}, issn = {2079-6382}, support = {FRG21-M-S35//American University of Sharjah/ ; }, abstract = {All currently approved antibiotics are being met by some degree of resistance by the bacteria they target. Biofilm formation is one of the crucial enablers of bacterial resistance, making it an important bacterial process to target for overcoming antibiotic resistance. Accordingly, several drug delivery systems that target biofilm formation have been developed. One of these systems is based on lipid-based nanocarriers (liposomes), which have shown strong efficacy against biofilms of bacterial pathogens. Liposomes come in various types, namely conventional (charged or neutral), stimuli-responsive, deformable, targeted, and stealth. This paper reviews studies employing liposomal formulations against biofilms of medically salient gram-negative and gram-positive bacterial species reported recently. When it comes to gram-negative species, liposomal formulations of various types were reported to be efficacious against Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, and members of the genera Klebsiella, Salmonella, Aeromonas, Serratia, Porphyromonas, and Prevotella. A range of liposomal formulations were also effective against gram-positive biofilms, including mostly biofilms of Staphylococcal strains, namely Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus subspecies bovis, followed by Streptococcal strains (pneumonia, oralis, and mutans), Cutibacterium acnes, Bacillus subtilis, Mycobacterium avium, Mycobacterium avium subsp. hominissuis, Mycobacterium abscessus, and Listeria monocytogenes biofilms. This review outlines the benefits and limitations of using liposomal formulations as means to combat different multidrug-resistant bacteria, urging the investigation of the effects of bacterial gram-stain on liposomal efficiency and the inclusion of pathogenic bacterial strains previously unstudied.}, } @article {pmid37237774, year = {2023}, author = {Neidhöfer, C and Rathore, K and Parčina, M and Sieber, MA}, title = {ESKAPEE Pathogen Biofilm Control on Surfaces with Probiotic Lactobacillaceae and Bacillus species.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {5}, pages = {}, pmid = {37237774}, issn = {2079-6382}, abstract = {Combatting the rapidly growing threat of antimicrobial resistance and reducing prevalence and transmission of ESKAPEE pathogens in healthcare settings requires innovative strategies, one of which is displacing these pathogens using beneficial microorganisms. Our review comprehensively examines the evidence of probiotic bacteria displacing ESKAPEE pathogens, with a focus on inanimate surfaces. A systematic search was conducted using the PubMed and Web of Science databases on 21 December 2021, and 143 studies were identified examining the effects of Lactobacillaceae and Bacillus spp. cells and products on the growth, colonization, and survival of ESKAPEE pathogens. While the diversity of study methods limits evidence analysis, results presented by narrative synthesis demonstrate that several species have the potential as cells or their products or supernatants to displace nosocomial infection-causing organisms in a variety of in vitro and in vivo settings. Our review aims to aid the development of new promising approaches to control pathogen biofilms in medical settings by informing researchers and policymakers about the potential of probiotics to combat nosocomial infections. More targeted studies are needed to assess safety and efficacy of different probiotic formulations, followed by large-scale studies to assess utility in infection control and medical practice.}, } @article {pmid37237757, year = {2023}, author = {Hwang, HJ and Li, DD and Lee, J and Kang, MK and Moon, HR and Lee, JH}, title = {Compounds That Have an Anti-Biofilm Effect against Common Bacteria at Very Low Concentrations and Their Antibiotic Combination Effect.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {5}, pages = {}, pmid = {37237757}, issn = {2079-6382}, support = {NRF-2019R1A2C1010087//National Research Foundation of Korea/ ; 2017M3A9E4078553//National Research Foundation of Korea/ ; 2021 BK21 FOUR Program//Pusan National University/ ; }, abstract = {Two synthetic compounds, MHY1383, azo-resveratrol and MHY1387, 5-[4-hydroxy-3,5-methoxybenzy]-2-thioxodihydropyrimidine-4,6[1H,5H]-dione have been reported to have an anti-biofilm effect on Pseudomonas aeruginosa at very low concentrations (1-10 pM). Here, we investigated the anti-biofilm effects of these compounds in various bacteria. We found that MHY1383 significantly inhibited Escherichia coli, Bacillus subtilis, and Staphylococcus aureus biofilm formation at 1 pM, 1 nM, and 10 nM, respectively. MHY1387 also inhibited the biofilm formation of E. coli, B. subtilis, and S. aureus at 1 pM, 10 nM, and 100 pM, respectively. Both MHY1383 and MHY1387 showed medium-dependent anti-biofilm effects on Salmonella enterica at high concentrations (10 μM). We also tested the susceptibility to antibiotics by measuring the minimum inhibitory concentration (MIC) in various bacteria. When P. aeruginosa, E. coli, B. subtilis, S. enterica, and S. aureus were treated with MHY1383 or MHY1387 in combination with four different antibiotics, the MICs of carbenicillin against B. subtilis and S. aureus were lowered more than two-fold by the combination with MHY1387. However, in all other combinations, the MIC changed within two-fold. The results of this study suggest that MHY1383 and MHY1387 are effective anti-biofilm agents and can be used at very low concentrations against biofilms formed by various types of bacteria. We also suggest that even if a substance that inhibits biofilm is used together with antibiotics, it does not necessarily have the effect of lowering the MIC of the antibiotics.}, } @article {pmid37237748, year = {2023}, author = {Martínez, A and Stashenko, EE and Sáez, RT and Zafra, G and Ortiz, C}, title = {Effect of Essential Oil from Lippia origanoides on the Transcriptional Expression of Genes Related to Quorum Sensing, Biofilm Formation, and Virulence of Escherichia coli and Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {5}, pages = {}, pmid = {37237748}, issn = {2079-6382}, abstract = {Microbial infections resistant to conventional antibiotics constitute one of the most important causes of mortality in the world. In some bacterial species, such as Escherichia coli and Staphylococcus aureus pathogens, biofilm formation can favor their antimicrobial resistance. These biofilm-forming bacteria produce a compact and protective matrix, allowing their adherence and colonization to different surfaces, and contributing to resistance, recurrence, and chronicity of the infections. Therefore, different therapeutic alternatives have been investigated to interrupt both cellular communication routes and biofilm formation. Among these, essential oils (EO) from Lippia origanoides thymol-carvacrol II chemotype (LOTC II) plants have demonstrated biological activity against different biofilm-forming pathogenic bacteria. In this work, we determined the effect of LOTC II EO on the expression of genes associated with quorum sensing (QS) communication, biofilm formation, and virulence of E. coli ATCC 25922 and S. aureus ATCC 29213. This EO was found to have high efficacy against biofilm formation, decreasing-by negative regulation-the expression of genes involved in motility (fimH), adherence and cellular aggregation (csgD), and exopolysaccharide production (pgaC) in E. coli. In addition, this effect was also determined in S. aureus where the L. origanoides EO diminished the expression of genes involved in QS communication (agrA), production of exopolysaccharides by PIA/PNG (icaA), synthesis of alpha hemolysin (hla), transcriptional regulators of the production of extracellular toxins (RNA III), QS and biofilm formation transcriptional regulators (sarA) and global regulators of biofilm formation (rbf and aur). Positive regulation was observed on the expression of genes encoding inhibitors of biofilm formation (e.g., sdiA and ariR). These findings suggest that LOTCII EO can affect biological pathways associated with QS communication, biofilm formation, and virulence of E. coli and S. aureus at subinhibitory concentrations and could be a promising candidate as a natural antibacterial alternative to conventional antibiotics.}, } @article {pmid37237611, year = {2023}, author = {Kurow, O and Nuwayhid, R and Stock, P and Steinert, M and Langer, S and Krämer, S and Metelmann, IB}, title = {Organotypic 3D Co-Culture of Human Pleura as a Novel In Vitro Model of Staphylococcus aureus Infection and Biofilm Development.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {37237611}, issn = {2306-5354}, abstract = {Bacterial pleural infections are associated with high mortality. Treatment is complicated due to biofilm formation. A common causative pathogen is Staphylococcus aureus (S. aureus). Since it is distinctly human-specific, rodent models do not provide adequate conditions for research. The purpose of this study was to examine the effects of S. aureus infection on human pleural mesothelial cells using a recently established 3D organotypic co-culture model of pleura derived from human specimens. After infection of our model with S. aureus, samples were harvested at defined time points. Histological analysis and immunostaining for tight junction proteins (c-Jun, VE-cadherin, and ZO-1) were performed, demonstrating changes comparable to in vivo empyema. The measurement of secreted cytokine levels (TNF-α, MCP-1, and IL-1β) proved host-pathogen interactions in our model. Similarly, mesothelial cells produced VEGF on in vivo levels. These findings were contrasted by vital, unimpaired cells in a sterile control model. We were able to establish a 3D organotypic in vitro co-culture model of human pleura infected with S. aureus resulting in the formation of biofilm, including host-pathogen interactions. This novel model could be a useful microenvironment tool for in vitro studies on biofilm in pleural empyema.}, } @article {pmid37237397, year = {2023}, author = {Zhang, Q and Peng, L and Han, W and Chen, H and Tang, H and Chen, X and Langford, PR and Huang, Q and Zhou, R and Li, L}, title = {The morphology and metabolic changes of Actinobacillus pleuropneumoniae during its growth as a biofilm.}, journal = {Veterinary research}, volume = {54}, number = {1}, pages = {42}, pmid = {37237397}, issn = {1297-9716}, support = {BB/S019901/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Swine ; Mice ; *Actinobacillus pleuropneumoniae/genetics ; Biofilms ; Transcriptome ; Virulence ; *Actinobacillus Infections/veterinary/microbiology ; *Rodent Diseases ; *Swine Diseases/microbiology ; }, abstract = {Actinobacillus pleuropneumoniae is an important swine respiratory pathogen. Previous studies have suggested that growth as a biofilm is a natural state of A. pleuropneumoniae infection. To understand the survival features involved in the biofilm state, the growth features, morphology and gene expression profiles of planktonic and biofilm A. pleuropneumoniae were compared. A. pleuropneumoniae in biofilms showed reduced viability but maintained the presence of extracellular polymeric substances (EPS) after late log-phase. Under the microscope, bacteria in biofilms formed dense aggregated structures that were connected by abundant EPS, with reduced condensed chromatin. By construction of Δpga and ΔdspB mutants, polymeric β-1,6-linked N-acetylglucosamine and dispersin B were confirmed to be critical for normal biofilm formation. RNA-seq analysis indicated that, compared to their planktonic counterparts, A. pleuropneumoniae in biofilms had an extensively altered transcriptome. Carbohydrate metabolism, energy metabolism and translation were significantly repressed, while fermentation and genes contributing to EPS synthesis and translocation were up-regulated. The regulators Fnr (HlyX) and Fis were found to be up-regulated and their binding motifs were identified in the majority of the differentially expressed genes, suggesting their coordinated global role in regulating biofilm metabolism. By comparing the transcriptome of wild-type biofilm and Δpga, the utilization of oligosaccharides, iron and sulfur and fermentation were found to be important in adhesion and aggregation during biofilm formation. Additionally, when used as inocula, biofilm bacteria showed reduced virulence in mouse, compared with planktonic grown cells. Thus, these results have identified new facets of A. pleuropneumoniae biofilm maintenance and regulation.}, } @article {pmid37236447, year = {2023}, author = {Elad, T and Hally, MP and Domingo-Félez, C and Knoop, O and Drewes, JE and Valverde-Pérez, B and Smets, BF}, title = {Exploring the effects of intermittent aeration on the performance of nitrifying membrane-aerated biofilm reactors.}, journal = {The Science of the total environment}, volume = {891}, number = {}, pages = {164329}, doi = {10.1016/j.scitotenv.2023.164329}, pmid = {37236447}, issn = {1879-1026}, abstract = {Membrane-aerated biofilm reactors (MABRs) are an emerging technology for nutrient removal; however, a trade-off remains between their removal rate and oxygen transfer efficiency. This study compares nitrifying flow-through MABRs operated under continuous and intermittent aeration modes at mainstream wastewater ammonia levels. The intermittently-aerated MABRs maintained maximal nitrification rates, including under conditions allowing the oxygen partial pressure on the gas side of the membrane to considerably drop during the no-aeration period. Nitrous oxide emissions of all reactors were comparable and amounted to approximately 20 % of the converted ammonia. Intermittent aeration increased the transformation rate constant of atenolol, yet did not affect the removal of sulfamethoxazole. Seven additional trace organic chemicals were not biodegraded by any of the reactors. The ammonia-oxidizing bacteria in the intermittently-aerated MABRs were dominated by Nitrosospira, previously shown to be abundant at low oxygen concentrations and provide reactor stability under changing conditions. Our findings indicate that intermittently-aerated flow-through MABRs can achieve high nitrification rates and oxygen transfer efficiencies, highlighting the possible implications of air supply discontinuity on nitrous oxide emissions and trace organic chemical biotransformation.}, } @article {pmid37236444, year = {2023}, author = {Guo, L and Ye, C and Yu, X and Horn, H}, title = {Induction of bacteria in biofilm into a VBNC state by chlorine and monitoring of biofilm structure changes by means of OCT.}, journal = {The Science of the total environment}, volume = {891}, number = {}, pages = {164294}, doi = {10.1016/j.scitotenv.2023.164294}, pmid = {37236444}, issn = {1879-1026}, abstract = {The occurrence of viable but non-culturable (VBNC) bacteria in drinking water may result in significant underestimation of viable cell counts detected by culture-based method, thus raising microbiological safety concern. Chlorine disinfection has been widely used in drinking water treatment to ensure microbiological safety. However, the effect of residual chlorine on inducing bacteria in biofilms into a VBNC state remains unclear. We determined cell numbers of Pseudomonas fluorescence in different physiological states (culturable, viable, dead) by heterotrophic plate count method and flow cytometer in a flow cell system under 0, 0.1, 0.5, 1.0 mg/L chlorine treatment. Numbers of culturable cells were 4.66 ± 0.47 Log10, 2.82 ± 0.76 Log10, 2.30 ± 1.23 Log10 (CFU/112.5 mm[3]) in each chlorine treatment group. However, viable cell numbers remained at 6.32 ± 0.05 Log10, 6.11 ± 0.24 Log10, 5.08 ± 0.81 Log10 (cells/112.5 mm[3]). Significant difference between numbers of viable and culturable cells demonstrated chlorine could induce bacteria in biofilms into a VBNC state. In this study, flow cells combination with Optical Coherence Tomography (OCT) were applied to construct an Automated experimental Platform for replicate Biofilm cultivation and structural Monitoring (APBM) system. The OCT imaging results demonstrated that changes of biofilm structure under chlorine treatment were closely related to their inherent characteristics. Biofilms with low thickness and high roughness coefficient or porosity were easier to be removed from the substratum. Biofilm with high rigid properties were more resistant to chlorine treatment. Even though >95 % bacteria in biofilms entered a VBNC state, the biofilm physical structure was still remained. This study revealed the possibility of bacteria to enter a VBNC state in drinking water biofilms and changes of biofilm structure with different characteristics under chlorine treatment, which provide reference for biofilms control in drinking water distribution systems.}, } @article {pmid37235946, year = {2023}, author = {Xu, Y and Liu, S and Zhao, H and Li, Y and Cui, C and Chou, W and Zhao, Y and Yang, J and Qiu, H and Zeng, J and Chen, D and Wu, S and Tan, Y and Wang, Y and Gu, Y}, title = {Ultrasonic irradiation enhanced the efficacy of antimicrobial photodynamic therapy against methicillin-resistant Staphylococcus aureus biofilm.}, journal = {Ultrasonics sonochemistry}, volume = {97}, number = {}, pages = {106423}, pmid = {37235946}, issn = {1873-2828}, mesh = {Animals ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Photosensitizing Agents/pharmacology ; Ultrasonics ; *Photochemotherapy/methods ; *Anti-Infective Agents/pharmacology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Mammals ; }, abstract = {Antimicrobial photodynamic therapy (aPDT) is a non-pharmacological antimicrobial regimen based on light, photosensitizer and oxygen. It has become a potential method to inactivate multidrug-resistant bacteria. However, limited by the delivery of photosensitizer (PS) in biofilm, eradicating biofilm-associated infections by aPDT remains challenging. This study aimed to explore the feasibility of combining ultrasonic irradiation with aPDT to enhance the efficacy of aPDT against methicillin-resistant staphylococcus aureus (MRSA) biofilm. A cationic benzylidene cyclopentanone photosensitizer with much higher selectivity to bacterial cells than mammalian cells were applied at the concentration of 10 μM. 532 nm laser (40 mW/cm[2], 10 min) and 1 MHz ultrasound (500 mW/cm[2], 10 min, simultaneously with aPDT) were employed against MRSA biofilms in vitro. In addition to combined with ultrasonic irradiation and aPDT, MRSA biofilms were treated with laser irradiation only, photosensitizer only, ultrasonic irradiation only, ultrasonic irradiation and photosensitizer, and aPDT respectively. The antibacterial efficacy was determined by XTT assay, and the penetration depth of PS in biofilm was observed using a photoluminescence spectrometer and a confocal laser scanning microscopy (CLSM). In addition, the viability of human dermal fibroblasts (WS-1 cells) after the same treatments mentioned above and the uptake of P3 by WS-1 cells after ultrasonic irradiation were detected by CCK-8 and CLSM in vitro. Results showed that the percent decrease in metabolic activity resulting from the US + aPDT group (75.76%) was higher than the sum of the aPDT group (44.14%) and the US group (9.88%), suggesting synergistic effects. Meanwhile, the diffusion of PS in the biofilm of MRSA was significantly increased by 1 MHz ultrasonic irradiation. Ultrasonic irradiation neither induced the PS uptake by WS-1 cells nor reduced the viability of WS-1 cells. These results suggested that 1 MHz ultrasonic irradiation significantly enhanced the efficacy of aPDT against MRSA biofilm by increasing the penetration depth of PS. In addition, the antibacterial efficacy of aPDT can be enhanced by ultrasonic irradiation, the US + aPDT treatment demonstrated encouraging in vivo antibacterial efficacy (1.73 log10 CFU/mL reduction). In conclusion, the combination of aPDT and 1 MHz ultrasound is a potential and promising strategy to eradicate biofilm-associated infections of MRSA.}, } @article {pmid37235500, year = {2023}, author = {Shi, X and Lin, L and Sun, J}, title = {The Value of Continuous Closed Negative Pressure Drainage Combined with Antibacterial Biofilm Dressing in Postoperative Wound Healing for Severe Pancreatitis.}, journal = {Alternative therapies in health and medicine}, volume = {}, number = {}, pages = {}, pmid = {37235500}, issn = {1078-6791}, abstract = {OBJECTIVE: To investigate the application value of continuous vacuum sealing drainage (VSD) combined with antibacterial biofilm hydraulic fiber dressing in wound healing after surgery for severe acute pancreatitis (SAP).

METHODS: A total of 82 SAP patients who underwent minimally invasive surgery in our hospital from March 2021 to September 2022 were randomly divided into two groups using a random number table method. Each group consisted of 41 cases. Both groups received surgical treatment, with the control group receiving VSD treatment and the observation group receiving VSD treatment combined with antibacterial biofilm hydraulic fiber dressing. The postoperative recovery efficiency, preoperative and postoperative wound area reduction rate, pressure ulcer healing score (PUSH), serum biological indicators (white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT)), and the rate of wound-related adverse reactions were compared between the two groups.

RESULTS: There was no statistical difference between the two groups in the time to resume eating (P > .05). However, the wound healing time and hospitalization days in the observation group were significantly shorter than those in the control group (P < .05). After 7 and 14 days of treatment, the wound area reduction rate in the observation group was significantly higher than in the control group, and the PUSH score was significantly lower than in the control group (P < .05). WBC, CRP, and PCT levels in the observation group were lower than in the control group (P < .05). The incidence of wound-related adverse reactions in the observation group (12.20%) was significantly lower than that in the control group (34.15%) (P < .05).

CONCLUSIONS: The application of VSD combined with antibacterial biofilm hydraulic fiber dressing in the postoperative wound healing of SAP has a significant effect. It improves wound healing efficiency, reduces pressure ulcer scores, decreases inflammation indicators, and lowers the incidence of adverse reactions. While further research is needed to determine its impact on infection and inflammation prevention, this treatment approach shows promise for clinical application.}, } @article {pmid37235397, year = {2023}, author = {Katsburg, M and Weingart, C and Aubry, E and Kershaw, O and Kikhney, J and Kursawe, L and Lübke-Becker, A and Moter, A and Skrodzki, M and Kohn, B and Fulde, M}, title = {Limiting Factors in Treatment Success of Biofilm-Forming Streptococci in the Case of Canine Infective Endocarditis Caused by Streptococcus canis.}, journal = {Veterinary sciences}, volume = {10}, number = {5}, pages = {}, pmid = {37235397}, issn = {2306-7381}, support = {FU 1027/3-1//Deutsche Forschungsgemeinschaft/ ; FU 1027/5-1//Deutsche Forschungsgemeinschaft/ ; S20-851-890//Petplan Charitable Trust foundation/ ; }, abstract = {An 8-year-old male Rhodesian Ridgeback was presented with fever and severe thrombocytopenia. Clinical and laboratory examination, echocardiography, blood culture, and pathohistology revealed evidence of infective endocarditis, ischemic renal infarcts, and septic encephalitis. Treatment was started immediately but the dog's condition worsened, and the dog had to be euthanized. The causative Streptococcus canis strain was detected by blood culture and MALDI-TOF MS and analyzed using whole-genome sequencing and multilocus sequence typing. Antibiotic susceptibility testing did not detect any resistance. The affected heart valve was analyzed using FISH imaging, which showed a streptococcal biofilm on the heart valve. Bacteria in biofilms are recalcitrant to antibiotic treatment. Early diagnosis could be beneficial to treatment outcome. Treatment of endocarditis could be improved by researching the optimal dosage of antibiotics in conjunction with the use of biofilm-active drugs.}, } @article {pmid37234778, year = {2023}, author = {Ren, Q and Luo, W and Chi, H and Zhang, L and Chen, W}, title = {Down-regulation of β-lactam antibiotics resistance and biofilm formation by Staphylococcus epidermidis is associated with isookanin.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1139796}, pmid = {37234778}, issn = {2235-2988}, mesh = {*Staphylococcus epidermidis/genetics ; *Anti-Bacterial Agents/pharmacology/metabolism ; Down-Regulation ; Molecular Docking Simulation ; Biofilms ; Monobactams/metabolism ; Microbial Sensitivity Tests ; }, abstract = {INTRODUCTION: Biofilm formation is the major pathogenicity of Staphylococcus epidermidis (S. epidermidis), which enhances bacterial resistance to antibiotics. Isookanin has potential inhibitory activity on biofilm.

METHOD: The inhibiting mechanisms of isookanin against biofilm formation through surface hydrophobicity assay, exopolysaccharides, eDNA, gene expression analysis, microscopic visualization, and molecular docking were explored. Additionally, the combination of isookanin and β-lactam antibiotics were evaluated by the broth micro-checkerboard assay.

RESULTS: The results showed that isookanin could decrease the biofilm formation of S. epidermidis by ≥85% at 250 μg/mL. The exopolysaccharides, eDNA and surface hydrophobicity were reduced after treatment with isookanin. Microscopic visualization analysis showed that there were fewer bacteria on the surface of the microscopic coverslip and the bacterial cell membrane was damaged after treatment with isookanin. The down-regulation of icaB and up-regulation of icaR were observed after treatment with isookanin. Additionally, the RNAIII gene was significantly up-regulated (p < 0.0001) at the mRNA level. Molecular docking showed that isookanin could bind to biofilm-related proteins. This indicated that isookanin can affect biofilm formation at the initial attachment phase and the aggregation phase. The FICI index showed that the combination of isookanin and β-lactam antibiotics were synergistic and could reduce doses of antibiotics by inhibiting biofilm formation.

DISCUSSION: This study improved the antibiotic susceptibility of S. epidermidis through inhibition of the biofilm formation, and provided a guidance for the treatment of antibiotic resistance caused by biofilm.}, } @article {pmid37234777, year = {2023}, author = {Alamiri, F and André, O and De, S and Nordenfelt, P and Hakansson, AP}, title = {Role of serotype and virulence determinants of Streptococcus pyogenes biofilm bacteria in internalization and persistence in epithelial cells in vitro.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1146431}, pmid = {37234777}, issn = {2235-2988}, mesh = {Humans ; *Streptococcus pyogenes/genetics ; Serogroup ; Virulence ; Actins/metabolism ; Bacterial Proteins/genetics/metabolism ; Epithelial Cells/microbiology ; Biofilms ; Virulence Factors/metabolism ; *Streptococcal Infections/microbiology ; }, abstract = {Streptococcus pyogenes causes a multitude of local and systemic infections, the most common being pharyngitis in children. Recurrent pharyngeal infections are common and are thought to be due to the re-emergence of intracellular GAS upon completion of antibiotic treatment. The role of colonizing biofilm bacteria in this process is not fully clear. Here, live respiratory epithelial cells were inoculated with broth-grown or biofilm bacteria of different M-types, as well as with isogenic mutants lacking common virulence factors. All M-types tested adhered to and were internalized into epithelial cells. Interestingly, internalization and persistence of planktonic bacteria varied significantly between strains, whereas biofilm bacteria were internalized in similar and higher numbers, and all strains persisted beyond 44 hours, showing a more homogenous phenotype. The M3 protein, but not the M1 or M5 proteins, was required for optimal uptake and persistence of both planktonic and biofilm bacteria inside cells. Moreover, the high expression of capsule and SLO inhibited cellular uptake and capsule expression was required for intracellular survival. Streptolysin S was required for optimal uptake and persistence of M3 planktonic bacteria, whereas SpeB improved intracellular survival of biofilm bacteria. Microscopy of internalized bacteria showed that planktonic bacteria were internalized in lower numbers as individual or small clumps of bacteria in the cytoplasm, whereas GAS biofilm bacteria displayed a pattern of perinuclear localization of bacterial aggregates that affected actin structure. Using inhibitors targeting cellular uptake pathways, we confirmed that planktonic GAS mainly uses a clathrin-mediated uptake pathway that also required actin and dynamin. Clathrin was not involved in biofilm internalization, but internalization required actin rearrangement and PI3 kinase activity, possibly suggesting macropinocytosis. Together these results provide a better understanding of the potential mechanisms of uptake and survival of various phenotypes of GAS bacteria relevant for colonization and recurrent infection.}, } @article {pmid37234036, year = {2023}, author = {Chen, Y and Gao, Y and Huang, Y and Jin, Q and Ji, J}, title = {Inhibiting Quorum Sensing by Active Targeted pH-Sensitive Nanoparticles for Enhanced Antibiotic Therapy of Biofilm-Associated Bacterial Infections.}, journal = {ACS nano}, volume = {17}, number = {11}, pages = {10019-10032}, doi = {10.1021/acsnano.2c12151}, pmid = {37234036}, issn = {1936-086X}, mesh = {Humans ; Quorum Sensing ; Endothelial Cells ; Biotin ; *Nanoparticles/therapeutic use ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Curcumin ; *Bacterial Infections/drug therapy ; Hydrogen-Ion Concentration ; }, abstract = {Inhibition of quorum sensing (QS) is considered as an effective strategy in combatting biofilm-associated bacterial infections. However, the application of quorum sensing inhibitors (QSI) is strongly restricted by poor water-solubility and low bioavailability. We herein fabricate pH-sensitive curcumin (Cur) loaded clustered nanoparticles with active targeting ability (denoted as anti-CD54@Cur-DA NPs) to inhibit QS for enhanced antibiotic therapy. Cur-DA NPs are first prepared through electrostatic interaction between Cur loaded amino-ended poly(amidoamine) dendrimer (PAMAM) and 2,3-dimethyl maleic anhydride (DA) modified biotin-poly(ethylene glycol)-polylysine (biotin-PEG-PLys). Anti-CD54@Cur-DA NPs are then obtained by the modification of Cur-DA NPs with anti-CD54. Cur loaded PAMAM can be released from Cur-DA NPs in acidic pH, leading to simultaneous charge reversal and size decrease, which is beneficial for biofilm penetration. Cur-DA NPs are hence much better in inhibiting QS than free Cur due to enhanced biofilm penetration. Compared to free Cur, Cur-DA NPs exhibit stronger capability in inhibiting the development of biofilm architecture and maturation, thus downregulating efflux pump-related genes and improving bactericidal performance of multiple antibiotics, including Penicillin G, ciprofloxacin, and tobramycin. Moreover, since anti-CD54 can selectively bind to inflamed endothelial cells, anti-CD54@Cur-DA NPs can be targeted accumulated in bacteria-infected tissues. The sequential treatment using anti-CD54@Cur-DA NPs and free antibiotics can effectively reduce bacterial burden and alleviate inflammation in a chronic lung infection model in vivo. This research provides an effective way to improve the therapeutic performance of QSI to enhance the anti-biofilm effects of antibiotics, which radiate a vitality of conventional antibiotics in treating biofilm-associated bacterial infections.}, } @article {pmid37233292, year = {2023}, author = {Salvador, A and Veiga, FF and Svidzinski, TIE and Negri, M}, title = {Case of Mixed Infection of Toenail Caused by Candida parapsilosis and Exophiala dermatitidis and In Vitro Effectiveness of Propolis Extract on Mixed Biofilm.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {37233292}, issn = {2309-608X}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 421620/2018-8//National Council for Scientific and Technological Development/ ; }, abstract = {Onychomycosis is a chronic fungal nail infection caused by several filamentous and yeast-like fungi, such as the genus Candida spp., of great clinical importance. Black yeasts, such as Exophiala dermatitidis, a closely related Candida spp. species, also act as opportunistic pathogens. Fungi infectious diseases are affected by organisms organized in biofilm in onychomycosis, making treatment even more difficult. This study aimed to evaluate the in vitro susceptibility profile to propolis extract and the ability to form a simple and mixed biofilm of two yeasts isolated from the same onychomycosis infection. The yeasts isolated from a patient with onychomycosis were identified as Candida parapsilosis sensu stricto and Exophiala dermatitidis. Both yeasts were able to form simple and mixed (in combination) biofilms. Notably, C. parapsilosis prevailed when presented in combination. The susceptibility profile of propolis extract showed action against E. dermatitidis and C. parapsilosis in planktonic form, but when the yeasts were in mixed biofilm, we only observed action against E. dermatitidis, until total eradication.}, } @article {pmid37233237, year = {2023}, author = {Zheng, L and Gu, X and Sun, L and Dong, M and Gao, A and Han, Z and Pan, H and Zhang, H}, title = {Adding Metal Ions to the Bacillus mojavensis D50 Promotes Biofilm Formation and Improves Ability of Biocontrol.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {37233237}, issn = {2309-608X}, support = {2019YFE0114200//Inter-governmental International Cooperation Special Project of National Key & D Program of China/ ; 20230203014SF//Key R&D projects of Jilin Provincial Science and Technology Development Plan/ ; }, abstract = {Bacillus mojavensis D50, a biocontrol strain, is used to prevent and treat the fungal plant pathogen Botrytis cinerea. Bacillus mojavensis D50's biofilms can affect its colonization; thus, the effects of different metal ions and culture conditions on biofilm formation were determined in this study. The results of medium optimization showed that Ca[2+] had the best ability to promote biofilm formation. The optimal medium composition for the formation of biofilms contained tryptone (10 g/L), CaCl2 (5.14 g/L), and yeast extract (5.0 g/L), and the optimal fermentation conditions included pH 7, a temperature of 31.4 °C, and a culture time of 51.8 h. We found that the antifungal activity and abilities to form biofilms and colonize roots were improved after optimization. In addition, the levels of expression of the genes luxS, SinR, FlhA, and tasA were up-regulated by 37.56-, 2.87-, 12.46-, and 6.22-fold, respectively. The soil enzymatic activities which related biocontrol-related enzymes were the highest when the soil was treated by strain D50 after optimization. In vivo biocontrol assays indicated that the biocontrol effect of strain D50 after optimization was improved.}, } @article {pmid37231227, year = {2023}, author = {Bajire, SK and Prabhu, A and Bhandary, YP and Irfan, KM and Shastry, RP}, title = {7-Ethoxycoumarin rescued Caenorhabditis elegans from infection of COPD derived clinical isolate Pseudomonas aeruginosa through virulence and biofilm inhibition via targeting Rhl and Pqs quorum sensing systems.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {8}, pages = {208}, pmid = {37231227}, issn = {1573-0972}, support = {BT/PR41393/MED/30/2298/2020//DBT, New Delhi/ ; }, mesh = {Animals ; *Quorum Sensing ; Virulence ; Pseudomonas aeruginosa ; Caenorhabditis elegans ; Biofilms ; Virulence Factors ; *Pulmonary Disease, Chronic Obstructive ; Bacterial Proteins/pharmacology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Pseudomonas aeruginosa is an ambidextrous Gram-negative contagium with density convoluted network defined quorum sensing, which enables the persistent survival within the host environment, contributing to various lung related diseases including Chronic Obstructive Pulmonary Disease (COPD). It is clear that P. aeruginosa is a powerful, exquisite pathogen that has adopted a variety of virulence properties through quorum sensing (QS) regulated phenomenon and that it dominates both in the development and exacerbations of COPD. Interestingly, 7-Ethoxycoumarin (7-EC), a compound that adequately mimics QS signaling molecule of P. aeruginosa, was introduced as part of the process of developing novel ways to treat the severe exacerbations. The results showed that, introduction of 7-EC significantly decreased exopolysaccharide-mediated biofilm development of strains isolated from COPD sputum, as evidenced by SEM analysis. Furthermore, 7-EC was able to modulate a variety of virulence factors and motility without subjecting planktonic cells to any selection pressure. Bacterial invasion assay revealed the potential activity of the 7-EC in preventing the active entry to A549 cells without causing any damage to the cells and found functionally active in protecting the C. elegans from P. aeruginosa infection and being non-toxic to the worms. Docking analysis was further proved that 7-EC to be the potential anti-QS compound competing specifically with Rhl and Pqs Systems. Therefore, 7-EC in the utilisation against the P. aeruginosa based infections, may open an avenue for the futuristic mechanistic study in chronic respiratory diseases and a initiator for the development of non-antibiotic based antibacterial therapy.}, } @article {pmid37230332, year = {2023}, author = {Siriweera, B and Siddiqui, M and Zou, X and Chen, G and Wu, D}, title = {Integrated thiosulfate-driven denitrification, partial nitrification and anammox process in membrane-aerated biofilm reactor for low-carbon, energy-efficient biological nitrogen removal.}, journal = {Bioresource technology}, volume = {382}, number = {}, pages = {129212}, doi = {10.1016/j.biortech.2023.129212}, pmid = {37230332}, issn = {1873-2976}, mesh = {*Nitrification ; *Denitrification ; Thiosulfates ; Nitrogen ; Carbon ; Anaerobic Ammonia Oxidation ; Bioreactors ; Biofilms ; Oxidation-Reduction ; }, abstract = {Combining multiple bioprocesses in a single membrane-aerated biofilm reactor (MABR) unit for wastewater treatment is an emerging research focus. This study investigated the feasibility of coupling thiosulfate-driven denitrification (TDD) with partial nitrification and anammox (PNA) in a MABR for the treatment of ammonium-containing wastewater. The integrated bioprocess was tested over a continuous operation period (>130 d) in two MABRs: one with a polyvinylidene fluoride membrane (MABR-1), and the other with micro-porous aeration tubes covered with non-wovenpolyester fabrics (MABR-2). After start-up, the MABR-1 and MABR-2 based on the TDD-PNA process achieved satisfactory total nitrogen removal efficiencies of 63% and 76%, with maximum oxygen utilisation efficiencies of up to 66% and 80% and nitrogen removal fluxes of 1.3 and 4.7 gN/(m[2]·d), respectively. Predictions from the AQUASIM-model verified the integrated bioprocess. These lab scale findings confirmed the applicability of MABR technology for simultaneous sulfur and nitrogen removal, promising for pilot-scale application.}, } @article {pmid37229517, year = {2023}, author = {Mello, TP and Barcellos, IC and Branquinha, MH and Santos, ALS}, title = {Cell dispersion during biofilm formation by Scedosporium apiospermum, Scedosporium aurantiacum, Scedosporium minutisporum and Lomentospora prolificans.}, journal = {Current research in microbial sciences}, volume = {4}, number = {}, pages = {100191}, pmid = {37229517}, issn = {2666-5174}, abstract = {Dispersion is an essential step in the lifecycle of biofilms, since it enables the dissemination of microbial cells and, consequently, the potential colonization of new sites. Filamentous fungi belonging to the Scedosporium/Lomentospora genera are opportunistic human pathogens able to form multidrug-resistant biofilms on surfaces of different chemical compositions, environments and nutritional conditions. Despite the rising understanding of how biofilms are formed by Scedosporium/Lomentospora species, the cell dispersal step has not yet been explored. In the present study, the cell dispersion was investigated during biofilm formation by S. apiospermum, S. minutisporum, S. aurantiacum and L. prolificans cells. The results revealed that conidia were the major type of dispersed cells, which were detected throughout biofilm development (from 24 to 72 h). Dispersion was not influenced by increased glucose concentration (the main source for energetic metabolism) neither the presence of voriconazole (the most common antifungal used to treat scedosporiosis); however, the presence of mucin (a component of mucous, present in the lungs of cystic fibrosis patients, who are usually affected by these filamentous fungi) triggered cell dispersion. Contrarily, a poor nutritional environment (e.g., phosphate-buffered saline) inhibited this step. Overall, our study reveals new insights into the biofilm development of Scedosporium/Lomentospora species.}, } @article {pmid37228667, year = {2023}, author = {Theis, TJ and Daubert, TA and Kluthe, KE and Brodd, KL and Nuxoll, AS}, title = {Staphylococcus aureus persisters are associated with reduced clearance in a catheter-associated biofilm infection.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1178526}, pmid = {37228667}, issn = {2235-2988}, mesh = {Animals ; Mice ; *Staphylococcus aureus/genetics/metabolism ; Drosophila melanogaster ; *Staphylococcal Infections/drug therapy ; Anti-Bacterial Agents/therapeutic use ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Staphylococcus aureus causes a wide variety of infections, many of which are chronic or relapsing in nature. Antibiotic therapy is often ineffective against S. aureus biofilm-mediated infections. Biofilms are difficult to treat partly due to their tolerance to antibiotics, however the underlying mechanism responsible for this remains unknown. One possible explanation is the presence of persister cells-dormant-like cells that exhibit tolerance to antibiotics. Recent studies have shown a connection between a fumC (fumarase C, a gene in the tricarboxylic acid cycle) knockout strain and increased survival to antibiotics, antimicrobial peptides, and in a Drosophila melanogaster model.

OBJECTIVE: It remained unclear whether a S. aureus high persister strain would have a survival advantage in the presence of innate and adaptive immunity. To further investigate this, a fumC knockout and wild type strains were examined in a murine catheter-associated biofilm model.

RESULTS: Interestingly, mice struggled to clear both S. aureus wild type and the fumC knockout strains. We reasoned both biofilm-mediated infections predominantly consisted of persister cells. To determine the persister cell population within biofilms, expression of a persister cell marker (Pcap5A::dsRED) in a biofilm was examined. Cell sorting of biofilms challenged with antibiotics revealed cells with intermediate and high expression of cap5A had 5.9-and 4.5-fold higher percent survival compared to cells with low cap5A expression. Based on previous findings that persisters are associated with reduced membrane potential, flow cytometry analysis was used to examine the metabolic state of cells within a biofilm. We confirmed cells within biofilms had reduced membrane potential compared to both stationary phase cultures (2.5-fold) and exponential phase cultures (22.4-fold). Supporting these findings, cells within a biofilm still exhibited tolerance to antibiotic challenge following dispersal of the matrix through proteinase K.

CONCLUSION: Collectively, these data show that biofilms are largely comprised of persister cells, and this may explain why biofilm infections are often chronic and/or relapsing in clinical settings.}, } @article {pmid37228184, year = {2023}, author = {Kandoth, N and Chaudhary, SP and Gupta, S and Raksha, K and Chatterjee, A and Gupta, S and Karuthedath, S and De Castro, CSP and Laquai, F and Pramanik, SK and Bhattacharyya, S and Mallick, AI and Das, A}, title = {Multimodal Biofilm Inactivation Using a Photocatalytic Bismuth Perovskite-TiO2-Ru(II)polypyridyl-Based Multisite Heterojunction.}, journal = {ACS nano}, volume = {17}, number = {11}, pages = {10393-10406}, doi = {10.1021/acsnano.3c01064}, pmid = {37228184}, issn = {1936-086X}, mesh = {*Bismuth/pharmacology/chemistry ; Reactive Oxygen Species ; *Biofilms ; }, abstract = {Infectious bacterial biofilms are recalcitrant to most antibiotics compared to their planktonic version, and the lack of appropriate therapeutic strategies for mitigating them poses a serious threat to clinical treatment. A ternary heterojunction material derived from a Bi-based perovskite-TiO2 hybrid and a [Ru(2,2'-bpy)2(4,4'-dicarboxy-2,2'-bpy)][2+] (2,2'-bpy, 2,2'-bipyridyl) as a photosensitizer (RuPS) is developed. This hybrid material is found to be capable of generating reactive oxygen species (ROS)/reactive nitrogen species (RNS) upon solar light irradiation. The aligned band edges and effective exciton dynamics between multisite heterojunctions are established by steady-state/time-resolved optical and other spectroscopic studies. Proposed mechanistic pathways for the photocatalytic generation of ROS/RNS are rationalized based on a cascade-redox processes arising from three catalytic centers. These ROS/RNS are utilized to demonstrate a proof-of-concept in treating two elusive bacterial biofilms while maintaining a high level of biocompatibility (IC50 > 1 mg/mL). The in situ generation of radical species (ROS/RNS) upon photoirradiation is established with EPR spectroscopic measurements and colorimetric assays. Experimental results showed improved efficacy toward biofilm inactivation of the ternary heterojunction material as compared to their individual/binary counterparts under solar light irradiation. The multisite heterojunction formation helped with better exciton delocalization for an efficient catalytic biofilm inactivation. This was rationalized based on the favorable exciton dissociation followed by the onset of multiple oxidation and reduction sites in the ternary heterojunction. This together with exceptional photoelectric features of lead-free halide perovskites outlines a proof-of-principle demonstration in biomedical optoelectronics addressing multimodal antibiofilm/antimicrobial modality.}, } @article {pmid37227545, year = {2023}, author = {Kuwada, N and Fujii, Y and Nakatani, T and Ousaka, D and Tsuji, T and Imai, Y and Kobayashi, Y and Oozawa, S and Kasahara, S and Tanemoto, K}, title = {Diamond-like carbon coating to inner surface of polyurethane tube reduces Staphylococcus aureus bacterial adhesion and biofilm formation.}, journal = {Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs}, volume = {}, number = {}, pages = {}, pmid = {37227545}, issn = {1619-0904}, abstract = {Staphylococcus aureus is one of the main causative bacteria for polyurethane catheter and artificial graft infection. Recently, we developed a unique technique for coating diamond-like carbon (DLC) inside the luminal resin structure of polyurethane tubes. This study aimed to elucidate the infection-preventing effects of diamond-like carbon (DLC) coating on a polyurethane surface against S. aureus. We applied DLC to polyurethane tubes and rolled polyurethane sheets with our newly developed DLC coating technique for resin tubes. The DLC-coated and uncoated polyurethane surfaces were tested in smoothness, hydrophilicity, zeta-potential, and anti-bacterial properties against S. aureus (biofilm formation and bacterial attachment) by contact with bacterial fluids under static and flow conditions. The DLC-coated polyurethane surface was significantly smoother, more hydrophilic, and had a more negative zeta-potential than did the uncoated polyurethane surface. Upon exposure to bacterial fluid under both static and flow conditions, DLC-coated polyurethane exhibited significantly less biofilm formation than uncoated polyurethane, based on absorbance measurements. In addition, the adherence of S. aureus was significantly lower for DLC-coated polyurethane than for uncoated polyurethane under both conditions, based on scanning electron microscopy. These results show that applying DLC coating to the luminal resin of polyurethane tubes may impart antimicrobial effects against S. aureus to implantable medical polyurethane devices, such as vascular grafts and central venous catheters.}, } @article {pmid37226152, year = {2023}, author = {Bakó, C and Balázs, VL and Kerekes, E and Kocsis, B and Nagy, DU and Szabó, P and Micalizzi, G and Mondello, L and Krisch, J and Pethő, D and Horváth, G}, title = {Flowering phenophases influence the antibacterial and anti-biofilm effects of Thymus vulgaris L. essential oil.}, journal = {BMC complementary medicine and therapies}, volume = {23}, number = {1}, pages = {168}, pmid = {37226152}, issn = {2662-7671}, mesh = {*Oils, Volatile/pharmacology ; *Thymus Plant ; Gas Chromatography-Mass Spectrometry ; Anti-Bacterial Agents/pharmacology ; }, abstract = {BACKGROUND: Essential oils are becoming increasingly popular in medicinal applications because of their antimicrobial effect. Thymus vulgaris L. (Lamiaceae) is a well-known and widely cultivated medicinal plant, which is used as a remedy for cold, cough and gastrointestinal symptoms. Essential oil content of thyme is responsible for its antimicrobial activity, however, it has been reported that the chemical composition of essential oils influences its biological activity. In order to explore flowering phenophases influence on the chemical composition of thyme essential oil and its antibacterial and anti-biofilm activity, plant materials were collected at the beginning of flowering, in full bloom and at the end of flowering periods in 2019.

METHODS: Essential oils from fresh and dried plant materials were distilled and analyzed with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The antibacterial activity was performed by broth microdilution and thin layer chromatography-direct bioautography (TLC-DB) assays and the anti-biofilm effect by crystal violet assay, respectively. Scanning electron microscopy was applied to illustrate the cellular changes of bacterial cells after essential oil treatment.

RESULTS: Thymol (52.33-62.46%) was the main component in the thyme essential oils. Thyme oil distilled from fresh plant material and collected at the beginning of flowering period exerted the highest antibacterial and anti-biofilm activity against Haemophilus influenzae, H. parainfluenzae and Pseudomonas aeruginosa.

CONCLUSION: The different flowering periods of Thymus vulgaris influence the antibacterial and anti-biofilm activity of its essential oils, therefore, the collection time has to be taken into consideration and not only the full bloom, but the beginning of flowering period may provide biological active thyme essential oil.}, } @article {pmid37224996, year = {2023}, author = {Karine Marcomini, E and Negri, M}, title = {Fungal quorum-sensing molecules and antiseptics: A promising strategy for biofilm modulation?.}, journal = {Drug discovery today}, volume = {28}, number = {7}, pages = {103624}, doi = {10.1016/j.drudis.2023.103624}, pmid = {37224996}, issn = {1878-5832}, mesh = {*Quorum Sensing ; *Anti-Infective Agents, Local/pharmacology ; Biofilms ; Antifungal Agents/pharmacology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {New strategies to control fungal biofilms are essential, especially those that interfere in the biofilm organization process and cellular communication, known as quorum sensing. The effect of antiseptics and quorum-sensing molecules (QSMs) have been considered with regard to this; however, little has been elucidated, particularly because studies are often restricted to the action of antiseptics and QSMs against a few fungal genera. In this review, we discuss progress reported in the literature thus far and analyze, through in silico methods, 13 fungal QSMs with regard to their physicochemical, pharmacological, and toxicity properties, including their mutagenicity, tumorigenicity, hepatotoxicity, and nephrotoxicity. From these in silico analyses, we highlight 4-hydroxyphenylacetic acid and tryptophol as having satisfactory properties and, thus, propose that these should be investigated further as antifungal agents. We also recommend future in vitro approaches to determine the association of QSMs with commonly used antiseptics as potential antibiofilm agents.}, } @article {pmid37224983, year = {2023}, author = {Gao, L and Tang, Z and Li, T and Wang, J}, title = {Myricetin exerts anti-biofilm activity and attenuates osteomyelitis by inhibiting the TLR2/MAPK pathway in experimental mice.}, journal = {Microbial pathogenesis}, volume = {}, number = {}, pages = {106165}, doi = {10.1016/j.micpath.2023.106165}, pmid = {37224983}, issn = {1096-1208}, abstract = {AIMS: To evaluate the potential of Myricetin against S.aureus induced osteomyelitis.

BACKGROUND: Osteomyelitis is infected condition of bone by micro-organisms. The mitogen-activated protein kinase (MAPK), inflammatory cytokines and Toll-like receptor-2 (TLR-2) pathway are mainly involved in osteomyelitis. Myricetin is a plant-food derived flavonoid which shows anti-inflammatory activity.

OBJECTIVE: In the present study, we evaluated the potential of Myricetin against S.aureus induced osteomyelitis. MC3T3-E1 cells were used for in vitro studies.

METHOD: Murine model of osteomyelitis was developed in BALB/c mice by injecting S.aureus in the medullary cavity of the femur. The mice were studied for bone destruction, anti-biofilm activity, osteoblast growth markers alkaline phosphatase (ALP), osteopontin (OCN) and collagen type-I (COLL-1) were studied by RT-PCR, ELISA analysis for levels of proinflammatory factors CRP, IL-6 and IL-1β. Expression of proteins by Western blot analysis and anti-biofilm effect by Sytox green dye fluorescence assay. Target confirmation was done by performing in silico docking analysis.

RESULTS: Myricetin reduced bone destruction in osteomyelitis induced mice. The treatment decreased bone levels of ALP, OCN, COLL-1 and TLR2. Myricetin decreased serum levels of CRP, IL-6 and IL-1β. The treatment suppressed activation of MAPK pathway and showed anti-biofilm effect. Docking studies suggested high binding affinity of Myricetin with MAPK protein in silico, by showing lower binding energies.

CONCLUSION: Myricetin suppresses osteomyelitis by inhibiting ALP, OCN, COLL-1 via the TLR2 and MAPK pathway involving inhibition of biofilm formation. In silico studies suggested MAPK as potential binding protein for myricetin.}, } @article {pmid37224668, year = {2023}, author = {Kim, B and Madukoma, CS and Shrout, JD and Nerenberg, R}, title = {Effect of EPS production on the performance of membrane-based biofilm reactors.}, journal = {Water research}, volume = {240}, number = {}, pages = {120101}, doi = {10.1016/j.watres.2023.120101}, pmid = {37224668}, issn = {1879-2448}, mesh = {*Extracellular Polymeric Substance Matrix ; *Biofilms ; Bacteria ; Bioreactors/microbiology ; Pseudomonas aeruginosa/genetics ; }, abstract = {This study explored the effect of extracellular polymeric substance (EPS) production on the performance of membrane-based biofilm reactors. Changing EPS production was induced by eliminating one of the main EPS polysaccharides, i.e., Pel. The studies were carried out using a pure culture of either Pseudomonas aeruginosa or an isogenic P. aeruginosa mutant that was unable to produce the Pel polysaccharide. The biofilm cell density for both strains was compared to confirm the Pel deletion mutant decreased overall EPS production in a bioreactor system. When the Pel-deficient mutant was grown as a biofilm, its cell density, i.e., ratio of cells/(cells + EPS), was 74 % higher than the wild type, showing EPS production was reduced by eliminating pel production. The growth kinetics were determined for both strains. The Pel-deficient mutant had a maximum specific growth rate (μ^) that was 14% higher than the wild type. Next, the effects of EPS reduction on reactor performance were assessed for a membrane aerated biofilm reactor (MABR) and a membrane bioreactor (MBR). For the MABR, the organic removal with the Pel-deficient mutant was around 8% higher than for the wild type. For the MBR, the time to reach the fouling threshold was 65 % greater for the Pel-deficient mutant than for the wild type. These results suggest that amount of EPS production can have significant effects on bacterial growth kinetics and bacterial cell density, which in turn can affect the performance of the membrane-based biofilm reactors. In both cases, lower EPS production correlated with more efficient treatment processes.}, } @article {pmid37223955, year = {2023}, author = {Jakkampudi, T and Lin, Q and Mitra, S and Vijai, A and Qin, W and Kang, A and Chen, J and Ryan, E and Wang, R and Gong, Y and Heinrich, F and Song, J and Di, YP and Tristram-Nagle, S}, title = {Lung SPLUNC1 Peptide Derivatives in the Lipid Membrane Headgroup Kill Gram-Negative Planktonic and Biofilm Bacteria.}, journal = {Biomacromolecules}, volume = {24}, number = {6}, pages = {2804-2815}, pmid = {37223955}, issn = {1526-4602}, support = {R01 AI133351/AI/NIAID NIH HHS/United States ; P30 GM124166/GM/NIGMS NIH HHS/United States ; R01 GM101647/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Bacteria ; Biofilms ; Gram-Negative Bacteria ; Lipids ; *Lung ; Microbial Sensitivity Tests ; Peptides ; }, abstract = {SPLUNC1 (short palate lung and nasal epithelial clone 1) is a multifunctional host defense protein found in human respiratory tract with antimicrobial properties. In this work, we compare the biological activities of four SPLUNC1 antimicrobial peptide (AMP) derivatives using paired clinical isolates of the Gram-negative (G(-)) bacteria Klebsiella pneumoniae, obtained from 11 patients with/without colistin resistance. Secondary structural studies were carried out to study interactions between the AMPs and lipid model membranes (LMMs) utilizing circular dichroism (CD). Two peptides were further characterized using X-ray diffuse scattering (XDS) and neutron reflectivity (NR). A4-153 displayed superior antibacterial activity in both G(-) planktonic cultures and biofilms. NR and XDS revealed that A4-153 (highest activity) is located primarily in membrane headgroups, while A4-198 (lowest activity) is located in hydrophobic interior. CD revealed that A4-153 is helical, while A4-198 has little helical character, demonstrating that helicity and efficacy are correlated in these SPLUNC1 AMPs.}, } @article {pmid37222596, year = {2023}, author = {Ma, D and Yu, M and Eszterhas, S and Rollenhagen, C and Lee, SA}, title = {A C. albicans TRAPP Complex-Associated Gene Contributes to Cell Wall Integrity, Hyphal and Biofilm Formation, and Tissue Invasion.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0536122}, pmid = {37222596}, issn = {2165-0497}, mesh = {Humans ; *Candida albicans/genetics ; *Fungal Proteins/genetics/metabolism ; Saccharomyces cerevisiae/metabolism ; Cell Wall/metabolism ; Biofilms ; Hyphae/metabolism ; }, abstract = {While endocytic and secretory pathways are well-studied cellular processes in the model yeast Saccharomyces cerevisiae, they remain understudied in the opportunistic fungal pathogen Candida albicans. We previously found that null mutants of C. albicans homologs of the S. cerevisiae early endocytosis genes ENT2 and END3 not only exhibited delayed endocytosis but also had defects in cell wall integrity, filamentation, biofilm formation, extracellular protease activity, and tissue invasion in an in vitro model. In this study, we focused on a potential C. albicans homolog to S. cerevisiae TCA17, which was discovered in our whole-genome bioinformatics approach aimed at identifying genes involved in endocytosis. In S. cerevisiae, TCA17 encodes a transport protein particle (TRAPP) complex-associated protein. Using a reverse genetics approach with CRISPR-Cas9-mediated gene deletion, we analyzed the function of the TCA17 homolog in C. albicans. Although the C. albicans tca17Δ/Δ null mutant did not have defects in endocytosis, it displayed an enlarged cell and vacuole morphology, impaired filamentation, and reduced biofilm formation. Moreover, the mutant exhibited altered sensitivity to cell wall stressors and antifungal agents. When assayed using an in vitro keratinocyte infection model, virulence properties were also diminished. Our findings indicate that C. albicans TCA17 may be involved in secretion-related vesicle transport and plays a role in cell wall and vacuolar integrity, hyphal and biofilm formation, and virulence. IMPORTANCE The fungal pathogen Candida albicans causes serious opportunistic infections in immunocompromised patients and has become a major cause of hospital-acquired bloodstream infections, catheter-associated infections, and invasive disease. However, due to a limited understanding of Candida molecular pathogenesis, clinical approaches for the prevention, diagnosis, and treatment of invasive candidiasis need significant improvement. In this study, we focus on identifying and characterizing a gene potentially involved in the C. albicans secretory pathway, as intracellular transport is critical for C. albicans virulence. We specifically investigated the role of this gene in filamentation, biofilm formation, and tissue invasion. Ultimately, these findings advance our current understanding of C. albicans biology and may have implications for the diagnosis and treatment of candidiasis.}, } @article {pmid37222591, year = {2023}, author = {Morrisette, T and Stamper, KC and Lev, KL and Kebriaei, R and Holger, DJ and Abdul-Mutakabbir, JC and Kunz Coyne, AJ and Rybak, MJ}, title = {Evaluation of Omadacycline Alone and in Combination with Rifampin against Staphylococcus aureus and Staphylococcus epidermidis in an In Vitro Pharmacokinetic/Pharmacodynamic Biofilm Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {67}, number = {6}, pages = {e0131722}, pmid = {37222591}, issn = {1098-6596}, support = {//Paratek Pharmaceuticals/ ; }, mesh = {Humans ; *Rifampin/pharmacology ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; Staphylococcus epidermidis ; *Staphylococcal Infections/drug therapy/microbiology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Biofilm-associated infections lead to substantial morbidity. Omadacycline (OMC) is a novel aminomethylcycline with potent in vitro activity against Staphylococcus aureus and Staphylococcus epidermidis, but data surrounding its use in biofilm-associated infections are lacking. We investigated the activity of OMC alone and in combination with rifampin (RIF) against 20 clinical strains of staphylococci in multiple in vitro biofilm analyses, including an in vitro pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor (CBR) model (simulating human exposures). The observed MICs for OMC demonstrated potent activity against the evaluated strains (0.125 to 1 mg/L), with an increase of MICs generally observed in the presence of biofilm (0.25 to >64 mg/L). Furthermore, RIF was shown to reduce OMC biofilm MICs (bMICs) in 90% of strains, and OMC plus RIF combination in biofilm time-kill analyses (TKAs) exhibited synergistic activity in most of the strains. Within the PK/PD CBR model, OMC monotherapy primarily displayed bacteriostatic activity, while RIF monotherapy generally exhibited initial bacterial eradication, followed by rapid regrowth likely due to the emergence of RIF resistance (RIF bMIC, >64 mg/L). However, the combination of OMC plus RIF produced rapid and sustained bactericidal activity in nearly all the strains (3.76 to 4.03 log10 CFU/cm[2] reductions from starting inoculum in strains in which bactericidal activity was reached). Furthermore, OMC was shown to prevent the emergence of RIF resistance. Our data provide preliminary evidence that OMC in combination with RIF could be a viable option for biofilm-associated infections with S. aureus and S. epidermidis. Further research involving OMC in biofilm-associated infections is warranted.}, } @article {pmid37222310, year = {2023}, author = {Tkachuk, N and Zelena, L}, title = {Bacterial sulfidogenic community from the surface of technogenic materials in vitro: composition and biofilm formation.}, journal = {Biofouling}, volume = {39}, number = {3}, pages = {327-338}, doi = {10.1080/08927014.2023.2215694}, pmid = {37222310}, issn = {1029-2454}, mesh = {*Polyethylene Terephthalates ; Biofilms ; Bacteria ; *Desulfovibrio ; Sulfates ; }, abstract = {Microbial biofilms of sulfate-reducing bacteria Desulfovibrio oryzae SRB1 and SRB2 were evaluated on polyethylene terephthalate in mono- and associative bacterial cultures. Bacillus velesensis strains C1 and C2b suppressed both the formation of biofilm and reduced the number of sulfate-reducing bacteria in the biofilm on the polyethylene terephthalate during the 50-day experiment. A decrease in the number of sulfate-reducing bacteria compared to the monoculture was also noted in association of D. oryzae SRB1 + Sat1 (bacterium-satellite of the sulfate-reducing bacteria). The strain Sat1 was identified as Anaerotignum (Clostridium) propionicum based on some microbiological, physiological and biochemical, genetic features. The importance of studying existing interactions between microorganisms in the ferrosphere and plastisphere is emphasized.}, } @article {pmid37221180, year = {2023}, author = {Noach, N and Lavy, E and Reifen, R and Friedman, M and Kirmayer, D and Zelinger, E and Ritter, A and Yaniv, D and Reifen, E}, title = {Zinc chloride is effective as an antibiotic in biofilm prevention following septoplasty.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {8344}, pmid = {37221180}, issn = {2045-2322}, mesh = {Humans ; *Nose ; *Zinc Compounds ; Anti-Bacterial Agents ; Biofilms ; }, abstract = {Biofilm-state bacterial infections associated with inserted medical devices constitute a massive health and financial problem worldwide. Although bacteria exhibit significantly lower susceptibility to antibiotics in the biofilm state, the most common treatment approach still relies on antibiotics, exacerbating the phenomenon of antibiotic-resistant bacteria. In this study, we aimed to assess whether ZnCl2 coating of intranasal silicone splints (ISSs) can reduce the biofilm infections associated with the insertion of these devices and prevent the overuse of antibiotics while minimizing waste, pollution and costs. We tested the ability of ZnCl2 to prevent biofilm formation on ISS both in vitro and in vivo by using the microtiter dish biofilm formation assay, crystal violet staining, and electron and confocal microscopy. We found a significant decrease in biofilm formation between the treatment group and the growth control when ZnCl2-coated splints were placed in patients' nasal flora. According to these results, infections associated with ISS insertion may be prevented by using ZnCl2 coating, thereby obviating the overuse and abuse of antibiotics.}, } @article {pmid37220603, year = {2023}, author = {de Menezes, CLA and Boscolo, M and da Silva, R and Gomes, E and da Silva, RR}, title = {The degradation of chicken feathers by Ochrobactrum intermedium results in antioxidant and metal chelating hydrolysates and proteolytic enzymes for staphylococcal biofilm dispersion.}, journal = {3 Biotech}, volume = {13}, number = {6}, pages = {202}, pmid = {37220603}, issn = {2190-572X}, abstract = {The increase in the generation of chicken feathers, due to the large production of the poultry industry, has created the need to search for ecologically safer ways to manage these residues. As a sustainable alternative for recycling keratin waste, we investigated the ability of the bacterium Ochrobactrum intermedium to hydrolyze chicken feathers and the valorization of the resulting enzymes and protein hydrolysate. In submerged fermentation with three different inoculum sizes (2.5, 5.0, and 10.0 mg of bacterial cells per 50 mL of medium), the fastest degradation of feathers was achieved with 5.0 mg cells, in which a complete decomposition of the substrate (96 h) and earlier peaks of keratinolytic and caseinolytic activities were detected. In the resulting protein hydrolysate, we noticed antioxidant and Fe[2+] and Cu[2+] chelating activities. ABTS scavenging, Fe[3+]-reducing ability and metal chelating activities of the fermentative samples followed the same trend of feather degradation; as feather mass decreased in the media, these activities increased. Furthermore, we noticed about 47% and 60% dispersion of established 7-day biofilms formed by S. aureus after enzymatic treatment for 5 h and 24 h, respectively. These findings highlight the potential use of this bacterium as an environmentally friendly alternative to treat this poultry waste and offer valuable products.}, } @article {pmid37217630, year = {2023}, author = {Zhao, W and Wang, Y and Bai, M}, title = {Nitrogen removal enhancement reinforced by nitritation/anammox in an anaerobic/oxic/anoxic system with integrated fixed biofilm activated sludge.}, journal = {Bioprocess and biosystems engineering}, volume = {46}, number = {7}, pages = {1065-1073}, pmid = {37217630}, issn = {1615-7605}, support = {ZR2020QE230//Natural Science Foundation of Shandong Province, China/ ; }, mesh = {*Ammonia/metabolism ; Sewage/microbiology ; *Ammonium Compounds/metabolism ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; Denitrification ; Nitrogen/metabolism ; Oxidation-Reduction ; Bioreactors/microbiology ; Bacteria/metabolism ; Biofilms ; }, abstract = {The enhancement of nitrogen removal was reinforced by nitritation/anammox in an anaerobic/oxic/anoxic (AOA) system of integrated fixed biofilm activated sludge. Nitritation was first attained by the method of free nitrous acid (FNA) inhibition with ammonia residues, and anaerobic ammonia oxidizing bacteria (AnAOB) were then added into the system, which enabled the occurrence of nitritation coupled with anaerobic ammonia oxidation (anammox). The results indicated that nitrogen removal was enhanced by the nitritation/anammox pathway with an efficiency of 88.9%. A microbial analysis showed that the ammonia oxidizing bacterium (AOB) Nitrosomonas was enriched on the biofilm (5.98%) and in the activated sludge (2.40%), and the AnAOB Candidatus Brocadia was detected on the biofilm with a proportion of 0.27%. Nitritation/anammox was attained and maintained due to the accumulation of functional bacteria.}, } @article {pmid37217567, year = {2023}, author = {Wardani, AK and Buana, EOGHN and Sutrisno, A}, title = {The potency of bacteriophages isolated from chicken intestine and beef tribe to control biofilm-forming bacteria, Bacillus subtilis.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {8222}, pmid = {37217567}, issn = {2045-2322}, mesh = {Animals ; Cattle ; Bacillus subtilis ; *Bacteriophages ; Chickens ; Biofilms ; *Disinfectants ; }, abstract = {Biofilm becomes one of the crucial food safety problems in the food industry as the formation of biofilm can be a source of contamination. To deal with the problem, an industry generally employs physical and chemical methods including sanitizers, disinfectants, and antimicrobials to remove biofilm. However, the use of these methods may bring about new problems, which are bacterial resistance in the biofilm and the risk for product contamination. New strategies to deal with bacterial biofilms are needed. Bacteriophages (phages), as a green alternative to chemical, have re-emerged as a promising approach to treat bacterial biofilm. In the present study, the potential of lytic phages which have antibiofilm activity on biofilm-forming bacteria (Bacillus subtilis), were isolated from chicken intestines and beef tripe obtained from Indonesian traditional markets using host cells obtained isolated from these samples. Phages isolation was conducted by using double layer agar technique. A lytic test of phages was administered on biofilm-forming bacteria. The difference of turbidity level between control (which were not infected by phages) and the test tubes containing host bacteria infected by phages was investigated. The infection time for the production of phages was determined based on the level of clarity of the media in the test tube with a longer lysate addition time. Three phages were isolated namely: ϕBS6, ϕBS8, and ϕUA7. It showed the ability to inhibit B. subtilis as biofilm-forming spoilage bacteria. The best inhibition results were obtained from ϕBS6. Infection with ϕBS6 in B. subtilis lead to 0.5 log cycle decreased in bacterial cells. This study showed that isolated phages might be used as a potential approach for handling the problem of biofilm formation by B. subtilis.}, } @article {pmid37217495, year = {2023}, author = {Cho, H and Ren, Z and Divaris, K and Roach, J and Lin, BM and Liu, C and Azcarate-Peril, MA and Simancas-Pallares, MA and Shrestha, P and Orlenko, A and Ginnis, J and North, KE and Zandona, AGF and Ribeiro, AA and Wu, D and Koo, H}, title = {Selenomonas sputigena acts as a pathobiont mediating spatial structure and biofilm virulence in early childhood caries.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {2919}, pmid = {37217495}, issn = {2041-1723}, support = {UL1 TR001111/TR/NCATS NIH HHS/United States ; U01 DE025046/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R03 DE028983/DE/NIDCR NIH HHS/United States ; R90 DE031532/DE/NIDCR NIH HHS/United States ; P30 DK034987/DK/NIDDK NIH HHS/United States ; P30 DK056350/DK/NIDDK NIH HHS/United States ; }, mesh = {Male ; Child ; Female ; Humans ; Child, Preschool ; Virulence ; *Dental Caries Susceptibility ; *Streptococcus mutans/genetics ; Biofilms ; }, abstract = {Streptococcus mutans has been implicated as the primary pathogen in childhood caries (tooth decay). While the role of polymicrobial communities is appreciated, it remains unclear whether other microorganisms are active contributors or interact with pathogens. Here, we integrate multi-omics of supragingival biofilm (dental plaque) from 416 preschool-age children (208 males and 208 females) in a discovery-validation pipeline to identify disease-relevant inter-species interactions. Sixteen taxa associate with childhood caries in metagenomics-metatranscriptomics analyses. Using multiscale/computational imaging and virulence assays, we examine biofilm formation dynamics, spatial arrangement, and metabolic activity of Selenomonas sputigena, Prevotella salivae and Leptotrichia wadei, either individually or with S. mutans. We show that S. sputigena, a flagellated anaerobe with previously unknown role in supragingival biofilm, becomes trapped in streptococcal exoglucans, loses motility but actively proliferates to build a honeycomb-like multicellular-superstructure encapsulating S. mutans, enhancing acidogenesis. Rodent model experiments reveal an unrecognized ability of S. sputigena to colonize supragingival tooth surfaces. While incapable of causing caries on its own, when co-infected with S. mutans, S. sputigena causes extensive tooth enamel lesions and exacerbates disease severity in vivo. In summary, we discover a pathobiont cooperating with a known pathogen to build a unique spatial structure and heighten biofilm virulence in a prevalent human disease.}, } @article {pmid37216726, year = {2023}, author = {Cohen, R and Mani, KA and Pirmatova, M and Jacobi, G and Zelinger, E and Belausov, E and Fallik, E and Banin, E and Mechrez, G}, title = {A green formulation for superhydrophobic coatings based on Pickering emulsion templating for anti-biofilm applications.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {227}, number = {}, pages = {113355}, doi = {10.1016/j.colsurfb.2023.113355}, pmid = {37216726}, issn = {1873-4367}, mesh = {Emulsions/chemistry ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; *Staphylococcus aureus ; Water ; }, abstract = {This study reports significant steps toward developing anti-biofilm surfaces based on superhydrophobic properties that meet the complex demands of today's food and medical regulations. It presents inverse Pickering emulsions of water in dimethyl carbonate (DMC) stabilized by hydrophobic silica (R202) as a possible food-grade coating formulation and describes its significant passive anti-biofilm properties. The final coatings are formed by applying the emulsions on the target surface, followed by evaporation to form a rough layer. Analysis shows that the final coatings exhibited a Contact Angle (CA) of up to 155° and a Roll-off Angle (RA) lower than 1° on the polypropylene (PP) surface, along with a relatively high light transition. Dissolving polycaprolactone (PCL) into the continuous phase enhanced the average CA and coating uniformity but hindered the anti-biofilm activity and light transmission. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a uniform coating by a "Swiss-cheese" like structure with high nanoscale and microscale roughness. Biofilm experiments confirm the coating's anti-biofilm abilities that led to the reduction in survival rates of S.aureus and E.coli, by 90-95% respectively, compared to uncoated PP surfaces.}, } @article {pmid37216386, year = {2023}, author = {Kitts, G and Rogers, A and Teschler, JK and Park, JH and Trebino, MA and Chaudry, I and Erill, I and Yildiz, FH}, title = {The Rvv two-component regulatory system regulates biofilm formation and colonization in Vibrio cholerae.}, journal = {PLoS pathogens}, volume = {19}, number = {5}, pages = {e1011415}, pmid = {37216386}, issn = {1553-7374}, support = {R01 AI114261/AI/NIAID NIH HHS/United States ; S10 OD023528/OD/NIH HHS/United States ; }, mesh = {Humans ; *Vibrio cholerae ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Virulence ; Phosphoric Monoester Hydrolases/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {The facultative human pathogen, Vibrio cholerae, employs two-component signal transduction systems (TCS) to sense and respond to environmental signals encountered during its infection cycle. TCSs consist of a sensor histidine kinase (HK) and a response regulator (RR); the V. cholerae genome encodes 43 HKs and 49 RRs, of which 25 are predicted to be cognate pairs. Using deletion mutants of each HK gene, we analyzed the transcription of vpsL, a biofilm gene required for Vibrio polysaccharide and biofilm formation. We found that a V. cholerae TCS that had not been studied before, now termed Rvv, controls biofilm gene transcription. The Rvv TCS is part of a three-gene operon that is present in 30% of Vibrionales species. The rvv operon encodes RvvA, the HK; RvvB, the cognate RR; and RvvC, a protein of unknown function. Deletion of rvvA increased transcription of biofilm genes and altered biofilm formation, while deletion of rvvB or rvvC lead to no changes in biofilm gene transcription. The phenotypes observed in ΔrvvA depend on RvvB. Mutating RvvB to mimic constitutively active and inactive versions of the RR only impacted phenotypes in the ΔrvvA genetic background. Mutating the conserved residue required for kinase activity in RvvA did not affect phenotypes, whereas mutation of the conserved residue required for phosphatase activity mimicked the phenotype of the rvvA mutant. Furthermore, ΔrvvA displayed a significant colonization defect which was dependent on RvvB and RvvB phosphorylation state, but not on VPS production. We found that RvvA's phosphatase activity regulates biofilm gene transcription, biofilm formation, and colonization phenotypes. This is the first systematic analysis of the role of V. cholerae HKs in biofilm gene transcription and resulted in the identification of a new regulator of biofilm formation and virulence, advancing our understanding of the role TCSs play in regulating these critical cellular processes in V. cholerae.}, } @article {pmid37214349, year = {2023}, author = {Auria, E and Deschamps, J and Briandet, R and Dupuy, B}, title = {Extracellular succinate induces spatially organized biofilm formation in Clostridioides difficile.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100125}, pmid = {37214349}, issn = {2590-2075}, abstract = {Clostridioides difficile infection associated to gut microbiome dysbiosis is the leading cause for nosocomial diarrhea. The ability of C. difficile to form biofilms has been progressively linked to its pathogenesis as well as its persistence in the gut. Although C. difficile has been reported to form biofilms in an increasing number of conditions, little is known about how these biofilms are formed in the gut and what factors may trigger their formation. Here we report that succinate, a metabolite abundantly produced by the dysbiotic gut microbiota, induces in vitro biofilm formation of C. difficile strains. We characterized the morphology and spatial composition of succinate-induced biofilms, and compared to non-induced or deoxycholate (DCA) induced biofilms. Biofilms induced by succinate are significantly thicker, structurally more complex, and poorer in proteins and exopolysaccharides (EPS). We then applied transcriptomics and genetics to characterize the early stages of succinate-induced biofilm formation and we showed that succinate-induced biofilm results from major metabolic shifts and cell-wall composition changes. Similar to DCA-induced biofilms, biofilms induced by succinate depend on the presence of a rapidly metabolized sugar. Finally, although succinate can be consumed by the bacteria, we found that the extracellular succinate is in fact responsible for the induction of biofilm formation through complex regulation involving global metabolic regulators and the osmotic stress response. Thus, our work suggests that as a gut signal, succinate may drive biofilm formation and help persistence of C. difficile in the gut, increasing the risk of relapse.}, } @article {pmid37214032, year = {2023}, author = {Tsopmene, UJ and Iwewe, YS and Eyong, IM and Bisso, BN and Dzoyem, JP}, title = {Antibiotic Resistance Profile, Biofilm Formation Ability, and Virulence Factors Analysis of Three Staphylococcus spp. Isolates From Urine.}, journal = {Cureus}, volume = {15}, number = {4}, pages = {e37877}, pmid = {37214032}, issn = {2168-8184}, abstract = {Background Staphylococcus spp. is one of the most causative agents of urinary tract infections (UTIs). This study aimed to investigate the antibiotic resistance profile and the virulence factors, including the biofilm formation ability of Staphylococcus spp. isolates from urine. Methodology The agar disk diffusion method was used to test the susceptibility of Staphylococcus isolates to ten antibiotics. The biofilm formation ability was determined using the safranin microplate-based method, and the phospholipase, esterase, and hemolysin activities were assessed by the agar plate method. Results During the study period, a prevalence of 18.12% of urinary tract infections caused by the identified Staphylococci was obtained. All the isolated Staphylococcus aureus and S. epidermidis were resistant to cefazolin. Multi-drug resistance (MDR) was recorded in 80.01%, 81.49%, and 76.20% of S. aureus, S. epidermidis, and S. saprophyticus isolates, respectively. Most of the isolates were moderate biofilm formers, while 44.44%, 31.75%, and 30.16% were positive for phospholipase, esterase, and hemolysin activities, respectively. No relevant correlations were observed between the ability of biofilm formation and the resistance to antibiotics or the expression of virulence factors investigated. Conclusion This study shows that Staphylococcus spp. isolates from patients with clinical manifestations of UTIs expressed a high degree of virulence factors, including the ability of biofilm formation, and exhibited multi-drug resistance to the majority of antimicrobials commonly used for the treatment of Staphylococcal infections.}, } @article {pmid37213696, year = {2023}, author = {Ahmad Ansari, F and Ahmad, I and Pichtel, J}, title = {Synergistic effects of biofilm-producing PGPR strains on wheat plant colonization, growth and soil resilience under drought stress.}, journal = {Saudi journal of biological sciences}, volume = {30}, number = {6}, pages = {103664}, pmid = {37213696}, issn = {1319-562X}, abstract = {Drought stress substantially impedes crop productivity throughout the world. Microbial based approaches have been considered a potential possibility and are under study. Based on our prior screening examination, two distinct and novel biofilm-forming PGPR strains namely Bacillus subtilis-FAB1 and Pseudomonas azotoformans-FAP3 are encompassed in this research. Bacterial biofilm development on glass surface, microtiter plate and seedling roots were assessed and characterized quantitatively and qualitatively by light and scanning electron microscopy. Above two isolates were further evaluated for their consistent performance by inoculating on wheat plants in a pot-soil system under water stresses. Bacterial moderate tolerance to ten-day drought was recorded on the application of individual strains with wheat plants; however, the FAB1 + FAP3 consortium expressively improved wheat survival during drought. The strains FAB1 and FAP3 displayed distinct and multifunctional plant growth stimulating attributes as well as effective roots and rhizosphere colonization in combination which could provide sustained wheat growth during drought. FAB1 and FAP3-induced alterations cooperatively conferred improved plant drought tolerance by controlling physiological traits (gs, Ci, E, iWUE and PN), stress indicators (SOD, CAT, GR, proline and MDA content) and also maintained physico-chemical attributes and hydrolytic enzymes including DHA, urease, ALP, protease, ACP and β glucosidase in the soil. Our findings could support future efforts to enhance plant drought tolerance by engineering the rhizobacterial biofilms and associated attributes which requires in-depth exploration and exploiting potential native strains for local agricultural application.}, } @article {pmid37213612, year = {2023}, author = {Zdziarski, P and Paściak, M and Chudzik, A and Kozińska, M and Augustynowicz-Kopeć, E and Gamian, A}, title = {Cutaneous tuberculosis-ambiguous transmission, bacterial diversity with biofilm formation in humoral abnormality: case report illustration.}, journal = {Frontiers in public health}, volume = {11}, number = {}, pages = {1091373}, pmid = {37213612}, issn = {2296-2565}, mesh = {Humans ; *Tuberculosis ; Biofilms ; }, abstract = {BACKGROUND: Cutaneous tuberculosis (CTB) and its paucibacillary forms are rare and difficult to diagnose, especially in immunocompromised patients with significant comorbidity. The aim of the study was to introduce the modern concept of the microbiome and diagnostic chain into clinical practice (patient-centered care) with the presentation of an atypical form of cutaneous tuberculosis with necrotizing non-healing ulcers leading to polymicrobial infection.

METHODS: The study material included samples from sputum, broncho-alveolar lavage and skin ulcer, taken from a patient developing cutaneous tuberculosis. The microbiological investigation was performed, and identification of the isolates was carried out using genotyping and the matrix-assisted laser desorption ionization-time of flight mass spectrometry.

RESULTS: The immunocompromised patient with humoral abnormality (plasma cell dyscrasia) and severe paraproteinemia developed multiorgan tuberculosis. Although cutaneous manifestation preceded systemic and pulmonary symptoms (approximately half a year), the mycobacterial genotyping confirmed the same MTB strain existence in skin ulcers and the respiratory system. Therefore, the infectious chain: transmission, the portal of entry, and bacterial spreading in vivo, were unclear. Microbial diversity found in wound microbiota (among others Gordonia bronchialis, Corynebacterium tuberculostearicum, Staphylococcus haemolyticus, and Pseudomonas oryzihabitans) was associated with the spread of a skin lesion. The in vitro biofilm-forming capacity of strains isolated from the wound may represent the potential virulence of these strains. Thus, the role of polymicrobial biofilm may be crucial in ulcer formation and CTB manifestation.

CONCLUSIONS: Severe wound healing as a unique biofilm-forming niche should be tested for Mycobacterium (on species and strain levels) and coexisting microorganisms using a wide range of microbiological techniques. In immunodeficient patients with non-typical CTB presentation, the chain of transmission and MTB spread is still an open issue for further research.}, } @article {pmid37213153, year = {2023}, author = {Wu, Y and Yang, D}, title = {Effects of Bacterial Biofilm on Regulation of Neurovascular Unit Functions and Neuroinflammation of Patients with Ischemic Cerebral Stroke by Immunocyte.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {1}, pages = {81-86}, doi = {10.14715/cmb/2022.69.1.14}, pmid = {37213153}, issn = {1165-158X}, mesh = {Rats ; Male ; Animals ; *Brain Ischemia ; Neuroinflammatory Diseases ; Inflammation ; *Ischemic Stroke ; Tumor Necrosis Factor-alpha ; Interleukin-6 ; Cerebral Infarction ; Infarction, Middle Cerebral Artery/complications ; }, abstract = {In this experiment, the effects of biofilm on neurovascular unit functions and neuroinflammation of patients with ischemic cerebral stroke were investigated. For this purpose, 20 adult male rats were purchased from Taconic (8 to 10 weeks old, weighing between 20 and 24g) and selected as the research objects. Then, they were randomly divided into an experimental group (10 rats) and a control group (10 rats). Ischemic cerebral stroke rat models were established. Besides, pseudomonas aeruginosa (PAO1) was prepared manually and implanted into the bodies of rats in the experimental group. mNSS scores, cerebral infarction area, and the release of inflammatory cytokines of rats in the two groups were compared. Results showed that mNSS scores for rats in the experimental group at all periods were remarkably higher than those for rats in the control group (P<0.05), which demonstrated that the rats in the experimental group suffered much severer neurological impairment than those in the control group. In addition, the release of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, inducible nitric oxide synthase (iNOS), and IL-10 were all higher than those of the control group (P<0.05). The cerebral infarction area of the experimental group at all periods was remarkably larger than that of the control group (P<0.05). In conclusion, the formation of biofilm led to the aggravation of neurological impairment and inflammatory reactions among patients with ischemic cerebral stroke.}, } @article {pmid37213152, year = {2023}, author = {Sun, H and Chai, X and Xu, G and Wei, S}, title = {The Formation and Drug Resistance Mechanism of Biofilm for Streptococcus pneumoniae Infection in Severe Respiratory Patients.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {69}, number = {1}, pages = {75-80}, doi = {10.14715/cmb/2022.69.1.13}, pmid = {37213152}, issn = {1165-158X}, mesh = {Humans ; *Levofloxacin/pharmacology/therapeutic use ; Moxifloxacin/pharmacology/therapeutic use ; DNA Topoisomerase IV/genetics ; *Pneumococcal Infections/drug therapy ; Streptococcus pneumoniae/genetics ; Microbial Sensitivity Tests ; Drug Resistance ; Penicillins ; Erythromycin/pharmacology/therapeutic use ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Drug Resistance, Bacterial/genetics ; Mutation/genetics ; }, abstract = {This study was to explore whether Streptococcus pneumoniae would form biofilms and the formative factors of biofilms, as well as the drug resistance mechanism of S. pneumoniae. In this study, a total of 150 strains of S. pneumoniae were collected from 5 local hospitals in the past two years, and the minimum inhibitory concentrations (MIC) of levofloxacin, moxifloxacin and penicillin were determined by agar double dilution method to select the drug-resistant strains. The polymerase chain reaction (PCR) amplification and sequencing were performed on specific genes of drug-resistant strains. In addition, 5 strains of S. pneumoniae with penicillin MIC ≤ 0.065 μg/mL, 0.5 μg/mL, 2 μg/mL, ≥ 4μg/mL were randomly selected, and the biofilms were cultured on two kinds of well plates for 24 hours. Finally, whether the biofilms were formed was observed. Experimental results revealed that the resistance rate of S. pneumoniae to erythromycin in this area was as high as 90.3%, and the strains that were resistant to penicillin account for only 1.5%. The amplification and sequencing experiment revealed that one (strain 1) of the strains, which was resistant to both drugs, had a GyrA mutation and ParE mutation, and strain 2 had a parC mutation. All strains generated biofilms, and the optical density (OD) value of penicillin MIC ≤ 0.065 μg/mL group (0.235 ± 0.053) was higher than that of 0.5 μg/mL group (0.192 ± 0.073) (P< 0.05) and higher than the OD value of the 4 μg/mL group (0.200 ± 0.041) (P< 0.05), showing statistically great differences. It was confirmed that the resistance rate of S. pneumoniae to erythromycin remained high, the rate of sensitivity to penicillin was relatively high, and the moxifloxacin and levofloxacin-resistant strains had appeared; S. pneumoniae mainly showed QRDR mutations in gyrA, parE, and parC; and it was confirmed that S. pneumoniae can generate biofilms in vitro.}, } @article {pmid37212952, year = {2023}, author = {Seebach, E and Elschner, T and Kraus, FV and Souto-Carneiro, M and Kubatzky, KF}, title = {Bacterial and Metabolic Factors of Staphylococcal Planktonic and Biofilm Environments Differentially Regulate Macrophage Immune Activation.}, journal = {Inflammation}, volume = {}, number = {}, pages = {}, pmid = {37212952}, issn = {1573-2576}, abstract = {Biofilm formation is a leading cause for chronic implant-related bone infections as biofilms shield bacteria against the immune system and antibiotics. Additionally, biofilms generate a metabolic microenvironment that shifts the immune response towards tolerance. Here, we compared the impact of the metabolite profile of bacterial environments on macrophage immune activation using Staphylococcus aureus (SA) and epidermidis (SE) conditioned media (CM) of planktonic and biofilm cultures. The biofilm environment had reduced glucose and increased lactate concentrations. Moreover, the expression of typical immune activation markers on macrophages was reduced in the biofilm environment compared to the respective planktonic CM. However, all CM caused a predominantly pro-inflammatory macrophage cytokine response with a comparable induction of Tnfa expression. In biofilm CM, this was accompanied by higher levels of anti-inflammatory Il10. Planktonic CM, on the other hand, induced an IRF7 mediated Ifnb gene expression which was absent in the biofilm environments. For SA but not for SE planktonic CM, this was accompanied by IRF3 activation. Stimulation of macrophages with TLR-2/-9 ligands under varying metabolic conditions revealed that, like in the biofilm setting, low glucose concentration reduced the Tnfa to Il10 mRNA ratio. However, the addition of extracellular L-lactate but not D-lactate increased the Tnfa to Il10 mRNA ratio upon TLR-2/-9 stimulation. In summary, our data indicate that the mechanisms behind the activation of macrophages differ between planktonic and biofilm environments. These differences are independent of the metabolite profiles, suggesting that the production of different bacterial factors is ultimately more important than the concentrations of glucose and lactate in the environment.}, } @article {pmid37212713, year = {2023}, author = {Wang, K and Deng, Y and Cui, X and Chen, M and Ou, Y and Li, D and Guo, M and Li, W}, title = {PatA Regulates Isoniazid Resistance by Mediating Mycolic Acid Synthesis and Controls Biofilm Formation by Affecting Lipid Synthesis in Mycobacteria.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0092823}, pmid = {37212713}, issn = {2165-0497}, support = {31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; 31870036//MOST | National Natural Science Foundation of China (NSFC)/ ; }, mesh = {Humans ; *Mycolic Acids/metabolism/pharmacology ; Isoniazid/pharmacology ; Mycobacterium smegmatis/metabolism ; *Mycobacterium tuberculosis ; Biofilms ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Lipids are prominent components of the mycobacterial cell wall, and they play critical roles not only in maintaining biofilm formation but also in resisting environmental stress, including drug resistance. However, information regarding the mechanism mediating mycobacterial lipid synthesis remains limited. PatA is a membrane-associated acyltransferase and synthesizes phosphatidyl-myo-inositol mannosides (PIMs) in mycobacteria. Here, we found that PatA could regulate the synthesis of lipids (except mycolic acids) to maintain biofilm formation and environmental stress resistance in Mycolicibacterium smegmatis. Interestingly, the deletion of patA significantly enhanced isoniazid (INH) resistance in M. smegmatis, although it reduced bacterial biofilm formation. This might be due to the fact that the patA deletion promoted the synthesis of mycolic acids through an unknown synthesis pathway other than the reported fatty acid synthase (FAS) pathway, which could effectively counteract the inhibition by INH of mycolic acid synthesis in mycobacteria. Furthermore, the amino acid sequences and physiological functions of PatA were highly conserved in mycobacteria. Therefore, we found a mycolic acid synthesis pathway regulated by PatA in mycobacteria. In addition, PatA also affected biofilm formation and environmental stress resistance by regulating the synthesis of lipids (except mycolic acids) in mycobacteria. IMPORTANCE Tuberculosis, caused by Mycobacterium tuberculosis, leads to a large number of human deaths every year. This is so serious, which is due mainly to the drug resistance of mycobacteria. INH kills M. tuberculosis by inhibiting the synthesis of mycolic acids, which are synthesized by the FAS pathway. However, whether there is another mycolic acid synthesis pathway is unknown. In this study, we found a PatA-mediated mycolic acid synthesis pathway that led to INH resistance of in patA-deleted mutant. In addition, we first report the regulatory effect of PatA on mycobacterial biofilm formation, which could affect the bacterial response to environmental stress. Our findings represent a new model for regulating biofilm formation by mycobacteria. More importantly, the discovery of the PatA-mediated mycolic acid synthesis pathway indicates that the study of mycobacterial lipids has entered a new stage, and the enzymes might be new targets of antituberculosis drugs.}, } @article {pmid37211854, year = {2023}, author = {Var, I and AlMatar, M and Heshmati, B and Albarri, O}, title = {Bacteriophage Cocktail Can Effectively Control Salmonella Biofilm on Gallstone and Tooth Surfaces.}, journal = {Current drug targets}, volume = {}, number = {}, pages = {}, doi = {10.2174/1389450124666230519121940}, pmid = {37211854}, issn = {1873-5592}, abstract = {Salmonellosis, which is typically distinguished by an immediate onset of fever, abdominal pain, diarrhea, nausea, and vomiting, is a bacterial infection caused by Salmonella. The rising incidence of antibiotic resistance in Salmonella Typhimurium is a major worldwide problem, and a better knowledge of the distribution of antibiotic resistance patterns in Salmonella Typhimurium is critical for selecting the best antibiotic for infection treatment. In this work, the efficiency of bacteriophage therapy of vegetative cells and biofilms of S. Typhimurium was investigated. Based on their host ranges, five Bacteriophages were chosen for therapy against 22 Salmonella isolates collected from various sources. PSCs1, PSDs1, PSCs2, PSSr1, and PSMc1 phages were found to exhibit potent anti-S. Typhimurium properties. In a 96-well microplate, the efficacy of bacteriophage therapy (105-1011 PFU/mL) against S. Typhimurium biofilm formers was first tested. A bacteriophage treatment (109 PFU/mL) was subsequently applied in the laboratory for 24 hours to minimize Salmonella adhering to the surfaces of gallstones and teeth. In 96-well microplate experiments, bacteriophage treatment inhibited biofilm development and reduced biofilm by up to 63.6% (P ≤ 0.05). When compared to controls, bacteriophages (PSCs1, PSDs1, PSCs2, PSSr1, PSMc1) demonstrated a rapid drop in the populations of S. Typhimurium biofilms generated on the surfaces of gallstones and teeth where the structure of the Salmonella bacteria in the biofilm was broken and holes were created. Clearly, this study indicated that phages might be employed to eliminate S. Typhimurium biofilms on gallstone and tooth surfaces.}, } @article {pmid37211593, year = {2023}, author = {Eghbalifam, N and Shojaosadati, SA and Hashemi-Najafabadi, S}, title = {Role of bioactive magnetic nanoparticles in the prevention of wound pathogenic biofilm formation using smart nanocomposites.}, journal = {Journal of nanobiotechnology}, volume = {21}, number = {1}, pages = {161}, pmid = {37211593}, issn = {1477-3155}, mesh = {*Metal Nanoparticles ; Wound Healing ; *Magnetite Nanoparticles ; Silver/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Nanocomposites ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Biofilm formation and its resistance to various antibiotics is a serious health problem in the treatment of wound infections. An ideal wound dressing should have characteristics such as protection of wound from microbial infection, suitable porosity (to absorb wound exudates), proper permeability (to maintain wound moisture), nontoxicity, and biocompatibility. Although silver nanoparticles (AgNPs) have been investigated as antimicrobial agents, their limitations in penetrating into the biofilm, affecting their efficiency, have consistently been an area for further research.

RESULTS: Consequently, in this study, the optimal amounts of natural and synthetic polymers combination, along with AgNPs, accompanied by iron oxide nanoparticles (IONPs), were utilized to fabricate a smart bionanocomposite that meets all the requirements of an ideal wound dressing. Superparamagnetic IONPs (with the average size of 11.8 nm) were synthesized through co-precipitation method using oleic acid to improve their stability. It was found that the addition of IONPs to bionanocomposites had a synergistic effect on their antibacterial and antibiofilm properties. Cytotoxicity assay results showed that nanoparticles does not considerably affect eukaryotic cells compared to prokaryotic cells. Based on the images obtained by confocal laser scanning microscopy (CLSM), significant AgNPs release was observed when an external magnetic field (EMF) was applied to the bionanocomposites loaded with IONPs, which increased the antibacterial activity and inhibited the formation of biofilm significantly.

CONCLUSION: These finding indicated that the nanocomposite recommended can have an efficient properties for the management of wounds through prevention and treatment of antibiotic-resistant biofilm.}, } @article {pmid37211260, year = {2023}, author = {Benavent, E and Ulldemolins, M and Haj, CE and Rigo-Bonnin, R and Yu, H and Wang, L and Wickremasinghe, H and Ariza, J and Murillo, O}, title = {Efficacy of meropenem extended infusion vs. intermittent bolus monotherapy and its combinations with colistin against Pseudomonas aeruginosa biofilm.}, journal = {International journal of antimicrobial agents}, volume = {}, number = {}, pages = {106856}, doi = {10.1016/j.ijantimicag.2023.106856}, pmid = {37211260}, issn = {1872-7913}, abstract = {INTRODUCTION: Device-related infections are difficult-to-treat due to biofilms. In this setting, optimizing the antibiotic efficacy is difficult since most PK/PD studies have been performed on planktonic cells, and therapies are limited when multidrug-resistant bacteria are involved. We aimed to analyze the PK/PD indices of meropenem predicting anti-biofilm efficacy against meropenem-susceptible and -resistant P. aeruginosa strains.

MATERIAL AND METHODS: Pharmacodynamics of meropenem dosages mimicking those of clinical practice (intermittent bolus of 2g every 8h; extended infusion of 2g over 4h every 8h), with and without colistin, were evaluated with the CDC Biofilm Reactor in vitro model for susceptible (PAO1) and extensively drug resistant (XDR-HUB3) P. aeruginosa. Efficacy was correlated with the pharmacokinetic/pharmacodynamic indices for meropenem.

RESULTS: Concerning PAO1, both meropenem regimens were bactericidal, with higher killing for the extended infusion (∆log10 CFU/mL 54-0h=-4.66±0.93 and ∆log10 CFU/mL 54-0h=-3.4±0.41 for intermittent bolus; p<0.001). Concerning XDR-HUB3, meropenem by intermittent bolus was non-active whereas it showed bactericidal effect by extended infusion (∆log10 CFU/mL 54-0h=-3.65±0.29; p<0.001). Time above minimum inhibitory concentration (f%T>MIC) had the best correlation with efficacy for both strains. Adding colistin always improved meropenem activity and resistant-strains did not emerge.

CONCLUSION: The f%T>MIC was the PK/PD index that best correlated with the anti-biofilm efficacy of meropenem; it was better optimized when using extended infusion, allowing to recover bactericidal activity in monotherapy also against meropenem-resistant P. aeruginosa. Combining meropenem by extended infusion with colistin offered the most effective therapy for both strains. Optimizing meropenem dosing by extended infusion should be encouraged when treating biofilm-related infections.}, } @article {pmid37211213, year = {2023}, author = {Queraltó, C and Ortega, C and Díaz-Yáñez, F and Inostroza, O and Espinoza, G and Álvarez, R and González, R and Parra, F and Paredes-Sabja, D and Acuña, LG and Calderón, IL and Fuentes, JA and Gil, F}, title = {The chaperone ClpC participates in sporulation, motility, biofilm, and toxin production of Clostridioides difficile.}, journal = {Journal of global antimicrobial resistance}, volume = {33}, number = {}, pages = {328-336}, doi = {10.1016/j.jgar.2023.05.004}, pmid = {37211213}, issn = {2213-7173}, mesh = {*Clostridioides difficile/genetics ; Clostridioides/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Anti-Bacterial Agents/metabolism ; }, abstract = {OBJECTIVES: Clostridioides difficile is a nosocomial pathogen that is associated with the use of antibiotics. One of the most worrying aspects of C. difficile infection is its ability to resist antimicrobial therapies, owing to spore formation. In several bacterial pathogens, proteases of the Clp family participate in phenotypes associated with persistence and virulence. This suggests that these proteins could be involved in virulence-related traits. In this study, we analysed the role of ClpC chaperone-protease of C. difficile in virulence-related traits by comparing the phenotypes of wild-type and mutant strains lacking the clpC gene (ΔclpC).

METHODS: We performed biofilm, motility, spore formation, and cytotoxicity assays.

RESULTS: Our results show significant differences between the wild-type and ΔclpC strains in all analysed parameters.

CONCLUSIONS: Based on these findings, we conclude that clpC plays a role in the virulence properties of C. difficile.}, } @article {pmid37211134, year = {2023}, author = {Saint-Aimé, R and Guittonny, M and Neculita, CM}, title = {Valorization potential of N-rich zeolite and moving bed biofilm reactor (MBBR) biomass in the revegetation of non-acid generating gold mine tailings.}, journal = {The Science of the total environment}, volume = {891}, number = {}, pages = {164279}, doi = {10.1016/j.scitotenv.2023.164279}, pmid = {37211134}, issn = {1879-1026}, abstract = {Treatment of ammonia nitrogen (NH3-N) in mine effluents generates N-rich residual materials, such as moving bed biofilm reactor (MBBR) biomass and spent zeolite. Using them as substitutes for mineral fertilizers in revegetation of mine tailings avoids disposal and contributes to a circular economy. The study evaluated the effect of MBBR biomass and N-rich zeolite amendments on above- and below-ground growth and foliar nutrient and trace element concentrations of a legume and several graminoid species grown on non-acid generating gold mine tailings. N-rich zeolite (clinoptilolite) was produced by treating saline (up to 60 mS/cm) synthetic and real mine effluents (250 vs 280 mg/L NH3-N). A three-month pot experiment was conducted with a dose of tested amendments equivalent to 100 kg/ha N and compared to unamended tailings (as negative control), tailings with a mineral NPK fertilizer, and a topsoil (as positive controls). Higher foliar N concentrations were found in amended and fertilized tailings vs negative control, but N was less available in the zeolite treatments than in other tailings treatments. For all plant species, the mean leaf area and above-ground, root, and total biomasses were similar in the zeolite-amended tailings to the unamended tailings, while the MBBR biomass amendment resulted in similar above- and below-ground growth to the NPK fertilized tailings and the commercial topsoil. Trace metal concentrations in water leaching from the amended tailings remained low, but tailings amended with zeolite exported NO3-N concentrations up to 10 times greater (>200 mg/L) after 28 days compared to all other treatments. Foliar Na concentrations in zeolite mixtures were six to nine times higher than in other treatments. The MBBR biomass is a promising potential amendment for revegetation of mine tailings. However, Se concentrations in plants after MBBR biomass amendment should not be underestimated, while Cr transfer from tailings to plants was observed.}, } @article {pmid37210905, year = {2023}, author = {Ferreres, G and Ivanova, K and Torrent-Burgués, J and Tzanov, T}, title = {Multimodal silver-chitosan-acylase nanoparticles inhibit bacterial growth and biofilm formation by Gram-negative Pseudomonas aeruginosa bacterium.}, journal = {Journal of colloid and interface science}, volume = {646}, number = {}, pages = {576-586}, doi = {10.1016/j.jcis.2023.04.184}, pmid = {37210905}, issn = {1095-7103}, mesh = {Humans ; Pseudomonas aeruginosa ; *Chitosan/pharmacology ; Silver/pharmacology ; *Metal Nanoparticles ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Anti-Infective Agents ; }, abstract = {Pseudomonas aeruginosa bacteria originate severe infections in hospitalized patients and those with chronic debilitating diseases leading to increased morbidity and mortality, longer hospitalization and huge financial burden to the healthcare system. The clinical relevance of P. aeruginosa infections is increased by the capability of this bacterium to grow in biofilms and develop multidrug resistant mechanisms that preclude conventional antibiotic treatments. Herein, we engineered novel multimodal nanocomposites that integrate in the same entity antimicrobial silver nanoparticles (NPs), the intrinsically antimicrobial, but biocompatible biopolymer chitosan, and the anti-infective quorum quenching enzyme acylase I. Acylase present in the NPs specifically degraded the signal molecules governing bacterial cell-to-cell communication and inhibited by ∼ 55 % P. aeruginosa biofilm formation, while the silver/chitosan template altered the integrity of bacterial membrane, leading to complete eradication of planktonic bacteria. The innovative combination of multiple bacteria targeting modalities resulted in 100-fold synergistic enhancement of the antimicrobial efficacy of the nanocomposite at lower and non-hazardous towards human skin cells concentrations, compared to the silver/chitosan NPs alone.}, } @article {pmid37210603, year = {2023}, author = {Fei, F and Wang, T and Jiang, Y and Chen, X and Ma, C and Zhou, M and Wu, Q and Cao, P and Duan, J and Chen, T and Burrows, JF and Wang, L}, title = {A frog-derived antimicrobial peptide as a potential anti-biofilm agent in combating Staphylococcus aureus skin infection.}, journal = {Journal of cellular and molecular medicine}, volume = {27}, number = {11}, pages = {1565-1579}, pmid = {37210603}, issn = {1582-4934}, mesh = {Animals ; Staphylococcus aureus ; Amino Acid Sequence ; Antimicrobial Peptides ; *Methicillin-Resistant Staphylococcus aureus ; *Dermatitis, Atopic/drug therapy ; *Anti-Infective Agents/pharmacology ; Anura ; Anti-Bacterial Agents/pharmacology ; Ranidae/metabolism ; Skin/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus aureus (S. aureus), one of the most prevalent bacteria found in atopic dermatitis lesions, can induce ongoing infections and inflammation by downregulating the expression of host defence peptides in the skin. In addition, the emergence of the 'superbug' Methicillin-resistant S. aureus (MRSA) has made the treatment of these infections more challenging. Antimicrobial peptides (AMPs), due to their potent antimicrobial activity, limited evidence of resistance development, and potential immunomodulatory effects, have gained increasing attention as potential therapeutic agents for atopic dermatitis. In this study, we report a novel AMP, brevinin-1E-OG9, isolated from the skin secretions of Odorrana grahami, which shows potent antibacterial activity, especially against S. aureus. Based on the characteristics of the 'Rana Box', we designed a set of brevinin-1E-OG9 analogues to explore its structure-activity relationship. Brevinin-1E-OG9c-De-NH2 exhibited the most potent antimicrobial efficacy in both in vitro and ex vivo studies and attenuated inflammatory responses induced by lipoteichoic acid and heat-killed microbes. As a result, brevinin-1E-OG9c-De-NH2 might represent a promising candidate for the treatment of S. aureus skin infections.}, } @article {pmid37210035, year = {2023}, author = {Wu, KK and Zhao, L and Zheng, XC and Sun, ZF and Wang, ZH and Chen, C and Xing, DF and Yang, SS and Ren, NQ}, title = {Recovery of methane and acetate during ex-situ biogas upgrading via novel dual-membrane aerated biofilm reactor.}, journal = {Bioresource technology}, volume = {382}, number = {}, pages = {129181}, doi = {10.1016/j.biortech.2023.129181}, pmid = {37210035}, issn = {1873-2976}, mesh = {*Bioreactors ; *Biofuels ; Methane ; Carbon Dioxide ; Biofilms ; Hydrogen ; }, abstract = {Biological biogas upgrading has been well-proven to be a promising approach for renewable bioenergy recovery, but hydrogen (H2)-assisted ex-situ biogas upgrading is hindered by a large solubility discrepancy between H2 and carbon dioxide (CO2). This study established a new dual-membrane aerated biofilm reactor (dMBfR) to improve the upgrading efficiency. Results showed that dMBfR operated at 1.25 atm H2 partial pressure, 1.5 atm biogas partial pressure, and 1.0 d hydraulic retention time could significantly improve the efficiency. The maximum methane purity of 97.6%, acetate production rate of 34.5 mmol L[-1]d[-1], and H2 and CO2 utilization ratios of 96.5% and 96.3% were achieved. Further analysis showed that the improved performances of biogas upgrading and acetate recovery were positively correlated with the total abundances of functional microorganisms. Taken together, these results suggest that the dMBfR, which facilitates the precise CO2 and H2 supply, is an ideal approach for efficient biological biogas upgrading.}, } @article {pmid37209516, year = {2023}, author = {Cui, Y and Gao, J and Zhao, M and Guo, Y and Zhao, Y and Wang, Z}, title = {Deciphering the interaction impacts between antiseptic benzethonium chloride and biofilm nitrification system: Performance, resistance mechanisms and biodegradation.}, journal = {Water research}, volume = {240}, number = {}, pages = {120062}, doi = {10.1016/j.watres.2023.120062}, pmid = {37209516}, issn = {1879-2448}, mesh = {*Nitrification ; Benzethonium/metabolism ; Wastewater ; *Anti-Infective Agents, Local ; Bacteria/genetics/metabolism ; Biofilms ; Oxidation-Reduction ; Bioreactors ; Ammonia/metabolism ; }, abstract = {Benzethonium chloride (BEC) is one of emerging bacteriostatic agents. BEC-bearing wastewater generated during sanitary applications in food and medication is easily combined with other wastewater streams to flow into wastewater treatment plants. This study focused on the long-term (231 days) impacts of BEC on the sequencing moving bed biofilm nitrification system. Nitrification performance was tolerant to low concentration of BEC (≤ 0.2 mg/L), but the nitrite oxidation was severely inhibited when the concentration of BEC was 1.0-2.0 mg/L. Partial nitrification maintained about 140 days with nitrite accumulation ratio over 80%, mainly caused by the inhibition of Nitrospira, Nitrotoga and Comammox. Notably, BEC exposure in the system might cause the co-selection of antibiotic resistance genes (ARGs) and disinfectant resistance genes (DRGs), and the resistance of biofilm system to BEC was strengthened by efflux pumps mechanism (qacEdelta1 and qacH) and antibiotic deactivation mechanism (aadA, aac(6')-Ib and blaTEM). Extracellular polymeric substances secretion and BEC biodegradation were also contributed to the system microorganisms resisting BEC exposure. In addition, Klebsiella, Enterobacter, Citrobacter and Pseudomonas were isolated and identified as BEC degrading bacteria. The metabolites of N,N-dimethylbenzylamine, N-benzylmethylamine and benzoic acid were identified, and the biodegradation pathway of BEC was proposed. This study brought new knowledge about the fate of BEC in biological treatment units and laid a foundation for its elimination from wastewater.}, } @article {pmid37209244, year = {2023}, author = {Karley, D and Shukla, SK and Rao, TS}, title = {Sequestration of cobalt and nickel by biofilm forming bacteria isolated from spent nuclear fuel pool water.}, journal = {Environmental monitoring and assessment}, volume = {195}, number = {6}, pages = {699}, pmid = {37209244}, issn = {1573-2959}, mesh = {*Cobalt ; Nickel/toxicity ; Water ; Environmental Monitoring ; *Metals, Heavy/toxicity ; Bacteria ; Biofilms ; }, abstract = {In the current study, six bacterial types, isolated from spent nuclear fuel (SNF) pool facility, were investigated for their ability to sequester heavy metals (cobalt and nickel). Biofilm formation by the six bacterial isolates, viz., Bacillus subtilis, Staphylococcus species, Staphylococcus arlettae, Staphylococcus epidermidis, Staphylococcus auricularis, and Chryseobacterium gleum, were assayed, and they were found to have significant biofilm forming property. Their biofilms were characterised using confocal scanning laser microscopy, and their potential to accumulate Co[2+] and Ni[2+] from bulk solutions was analysed with respect to time. A comparative assessment of bioaccumulation capacity was done using biofilms, planktonic cells, and live vs dead cells. The strains accumulated Co[2+] and Ni[2+] in the range of 4 × 10[-4] to 1 × 10[-5] g/mg of cell biomass. It is interesting to note that dead biomass also showed significant removal of the two metal ions, suggesting an alternative process for metal removal. This study suggests that hostile environments can be a repertoire of putative bacterial species with potential heavy metals and other contaminants remediation properties.}, } @article {pmid37207853, year = {2023}, author = {Çam, S and Küçük, Ç and Almaca, A}, title = {Bacillus strains exhibit various plant growth promoting traits and their biofilm-forming capability correlates to their salt stress alleviation effect on maize seedlings.}, journal = {Journal of biotechnology}, volume = {369}, number = {}, pages = {35-42}, doi = {10.1016/j.jbiotec.2023.05.004}, pmid = {37207853}, issn = {1873-4863}, mesh = {*Bacillus ; Zea mays/microbiology ; Seedlings ; Antifungal Agents ; Salt Stress ; Phosphates ; Biofilms ; Plant Roots ; }, abstract = {Soil salinity interferes with plant growth and development. Bacillus genus has been used to increase the growth and productivity of a wide variety of crops by alleviating the effects of salt stress. A total of thirty two Bacillus isolates were obtained from maize rhizosphere, and their plant growth-promoting (PGP) traits and biocontrol activities were tested. Bacillus isolates displayed varying degrees of PGP properties-the production of extracellular enzymes, indole acetic acid, hydrogen cyanide, phosphate solubilization, biofilm formation, and antifungal potential against several fungal pathogens. The phosphate-solubilizing isolates belong to B. safensis, B. thuringiensis, B. cereus, and B. megaterium species. Each Bacillus isolate demonstrated different levels of antifungal activity against the fungal pathogens tested. Biofilm production by some salt-tolerant isolates significantly increased at elevated levels of NaCl (p < 0.05). The strains B. safensis B24, B. halotolerans B7/B18, B. subtilis B26, and B. thuringiensis B10 significantly increased the length of root (by 32.7-38.2%) and shoot (by 19.5-29.8%) of maize (p < 0.05). Maize plants treated with some Bacillus strains displayed significantly greater chlorophyll content with an increase of 26.7-32.1% (p < 0.05). Among PGP properties, enhanced biofilm formation played a more important role in maize growth under higher salinity. These salt-tolerant biofilm-forming strains could be efficiently used as bio-inoculant for maize under salinity stress.}, } @article {pmid37207779, year = {2023}, author = {Chen, X and Li, D and Zhou, C and Liu, X and Liu, G}, title = {Predation preference for extracellular polysaccharides by paramecia and rotifers may have accelerated the decline of membrane biofilm hydraulic resistance.}, journal = {The Science of the total environment}, volume = {889}, number = {}, pages = {164090}, doi = {10.1016/j.scitotenv.2023.164090}, pmid = {37207779}, issn = {1879-1026}, mesh = {Animals ; *Extracellular Polymeric Substance Matrix ; *Predatory Behavior ; Membranes, Artificial ; Biofilms ; Polysaccharides ; Proteins ; }, abstract = {The hydraulic resistance of biofilm layer on membranes impacts the filtration resistance significantly. The effect of predation by two model microfauna (i.e., paramecia and rotifers) on the hydraulic resistance, structure, extracellular polymeric substance (EPS), and bacterial community of biofilms developed on supporting materials (i.e., nylon mesh) was evaluated in this study. Long-term experiments demonstrated that predation could alter biofilm compositions and accelerated the decline of hydraulic resistance by increasing biofilm heterogeneity and deformation. Importantly, predation preference of paramecia and rotifers on biofilm components were further investigated for the first time by tracking the fluorescence change in the predator bodies after exposure to the stained biofilms. Results indicated that after 12-hour's incubation, the ratio of extracellular α-polysaccharides (α-PS) to proteins (PN) within the bodies of paramecia and rotifers increased to 2.6 and 3.9, respectively, which was 0.76 in the original biofilms. The ratios of α-PS/live cells within paramecia and rotifers increased to 1.42 and 1.64 from 0.81 in the original biofilms. The ratio of live/dead cells in the predator bodies, however, changed slightly compared to the original biofilms. These results clearly and directly evidenced that both paramecia and rotifers could feed on biofilm EPS and cells, but having a significant preference for PS over PN and cells. Since extracellular PS is recognized as a primary biofilm adhesion agent, the preference for PS could better explain why predation had accelerated the disintegration and hydraulic resistance decline of mesh biofilms.}, } @article {pmid37206316, year = {2023}, author = {Nandy, A and Farkas, D and Pepió-Tárrega, B and Martinez-Crespiera, S and Borràs, E and Avignone-Rossa, C and Di Lorenzo, M}, title = {Influence of carbon-based cathodes on biofilm composition and electrochemical performance in soil microbial fuel cells.}, journal = {Environmental science and ecotechnology}, volume = {16}, number = {}, pages = {100276}, pmid = {37206316}, issn = {2666-4984}, abstract = {Increasing energy demands and environmental pollution concerns press for sustainable and environmentally friendly technologies. Soil microbial fuel cell (SMFC) technology has great potential for carbon-neutral bioenergy generation and self-powered electrochemical bioremediation. In this study, an in-depth assessment on the effect of several carbon-based cathode materials on the electrochemical performance of SMFCs is provided for the first time. An innovative carbon nanofibers electrode doped with Fe (CNFFe) is used as cathode material in membrane-less SMFCs, and the performance of the resulting device is compared with SMFCs implementing either Pt-doped carbon cloth (PtC), carbon cloth, or graphite felt (GF) as the cathode. Electrochemical analyses are integrated with microbial analyses to assess the impact on both electrogenesis and microbial composition of the anodic and cathodic biofilm. The results show that CNFFe and PtC generate very stable performances, with a peak power density (with respect to the cathode geometric area) of 25.5 and 30.4 mW m[-2], respectively. The best electrochemical performance was obtained with GF, with a peak power density of 87.3 mW m[-2]. Taxonomic profiling of the microbial communities revealed differences between anodic and cathodic communities. The anodes were predominantly enriched with Geobacter and Pseudomonas species, while cathodic communities were dominated by hydrogen-producing and hydrogenotrophic bacteria, indicating H2 cycling as a possible electron transfer mechanism. The presence of nitrate-reducing bacteria, combined with the results of cyclic voltammograms, suggests microbial nitrate reduction occurred on GF cathodes. The results of this study can contribute to the development of effective SMFC design strategies for field implementation.}, } @article {pmid37205937, year = {2023}, author = {Khoshnood, S and Akrami, S and Saki, M and Motahar, M and Masihzadeh, S and Daneshfar, S and Meghdadi, H and Abbasi Montazeri, E and Abdi, M and Farshadzadeh, Z}, title = {Molecular evaluation of aminoglycosides resistance and biofilm formation in Klebsiella pneumoniae clinical isolates: A cross-sectional study.}, journal = {Health science reports}, volume = {6}, number = {5}, pages = {e1266}, pmid = {37205937}, issn = {2398-8835}, abstract = {BACKGROUND AND AIMS: Resistance to antibiotics and the capability to develop biofilm as two main virulent determinants of Klebsiella pneumoniae have important role in infection persistence. The aim of the study was to evaluate the association between the prevalence of aminoglycoside resistance and virulence genes and biofilm formation capacity in K. pneumoniae strains isolated from hospitalized patients in South-West of Iran.

METHODS: A total of 114 non-duplicate clinical isolates of K. pneumoniae collected from Ahvaz teaching hospitals. Identification of species was performed by biochemical tests and then confirmed by polymerase chain reaction (PCR) of rpoB gene. The susceptibility to antibiotics was determined by Kirby-Bauer disk diffusion method. Biofilm formation was assessed by microtiter plate method. Finally, PCR was conducted to detect virulence gene determinants including fimbrial genes, aminoglycoside modifying enzymes- and 16S rRNA methylase (RMTase) genes.

RESULTS: Totally, all collected strains were carbapenem resistant and showed multidrug- and extensively drug-resistance phenotype (75% and 25%, respectively). Seventy-one percent (n = 81) of isolates were non-susceptible to aminoglycosides. Among aminoglycoside antibiotics, K. pneumoniae isolates showed the highest and lowest resistance rates to tobramycin (71%) and the amikacin (25%), respectively. All biofilm producer strains were positive for the presence virulence determinants including ecpA, fimA, mrkD, and mrkA. Of 81 aminoglycosides non-susceptible isolates 33% were positive for the presence ant (2″)-Ia as the most prevalent gene followed by aac (3')-IIa and armA (27%), aac (6')-Ib (18%), and aph (3')-Ia (15%).

CONCLUSION: K. pneumoniae isolates showed the highest and the lowest aminoglycoside resistance rates to tobramycin and amikacin, respectively. Majority of isolates were biofilm producers and there was significant association between antibiotic resistance pattern and the strength of biofilm production. The ant(2″)-Ia, aac (3')-IIa, and armA genes in aminoglycoside-resistant isolates.}, } @article {pmid37205794, year = {2023}, author = {Markale, I and Carrel, M and Kurz, DL and Morales, VL and Holzner, M and Jiménez-Martínez, J}, title = {Internal Biofilm Heterogeneities Enhance Solute Mixing and Chemical Reactions in Porous Media.}, journal = {Environmental science & technology}, volume = {57}, number = {21}, pages = {8065-8074}, doi = {10.1021/acs.est.2c09082}, pmid = {37205794}, issn = {1520-5851}, mesh = {Porosity ; *Biofilms ; *Hydrodynamics ; Biological Transport ; Permeability ; Bacteria ; }, abstract = {Bacterial biofilms can form in porous media that are of interest in industrial applications ranging from medical implants to biofilters as well as in environmental applications such as in situ groundwater remediation, where they can be critical locations for biogeochemical reactions. The presence of biofilms modifies porous media topology and hydrodynamics by clogging pores and consequently solutes transport and reactions kinetics. The interplay between highly heterogeneous flow fields found in porous media and microbial behavior, including biofilm growth, results in a spatially heterogeneous biofilm distribution in the porous media as well as internal heterogeneity across the thickness of the biofilm. Our study leverages highly resolved three-dimensional X-ray computed microtomography images of bacterial biofilms in a tubular reactor to numerically compute pore-scale fluid flow and solute transport by considering multiple equivalent stochastically generated internal permeability fields for the biofilm. We show that the internal heterogeneous permeability mainly impacts intermediate velocities when compared with homogeneous biofilm permeability. While the equivalent internal permeability fields of the biofilm do not impact fluid-fluid mixing, they significantly control a fast reaction. For biologically driven reactions such as nutrient or contaminant uptake by the biofilm, its internal permeability field controls the efficiency of the process. This study highlights the importance of considering the internal heterogeneity of biofilms to better predict reactivity in industrial and environmental bioclogged porous systems.}, } @article {pmid37204124, year = {2023}, author = {Middlemiss, AD and Haycocks, JRJ and Stringer, AM and Piddock, LJV and Wade, JT and Grainger, DC}, title = {Mapping direct and indirect MarA/SoxS/Rob/RamA regulons in Salmonella Typhimurium reveals repression of csgD and biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {5}, pages = {}, pmid = {37204124}, issn = {1465-2080}, support = {/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*DNA-Binding Proteins/metabolism ; Trans-Activators/genetics/metabolism ; Salmonella typhimurium/genetics/metabolism ; *Escherichia coli Proteins/genetics ; Regulon ; Phylogeny ; Gene Expression Regulation, Bacterial ; Transcription Factors/genetics/metabolism ; Escherichia coli/genetics/metabolism ; Biofilms ; Bacterial Proteins/genetics/metabolism ; }, abstract = {The closely related transcription factors MarA, SoxS, Rob and RamA control overlapping stress responses in many enteric bacteria. Furthermore, constitutive expression of such regulators is linked to clinical antibiotic resistance. In this work we have mapped the binding of MarA, SoxS, Rob and RamA across the Salmonella Typhimurium genome. In parallel, we have monitored changes in transcription start site use resulting from expression of the regulators. Together, these data allow direct and indirect gene regulatory effects to be disentangled. Promoter architecture across the regulon can also be deduced. At a phylogenetic scale, around one third of regulatory targets are conserved in most organisms encoding MarA, SoxS, Rob or RamA. We focused our attention on the control of csgD, which encodes a transcriptional activator responsible for stimulating production of curli fibres during biofilm formation. We show that expression of csgD is particularly sensitive to SoxS that binds upstream to repress transcription. This differs to the situation in Escherichia coli, where MarA regulates csgD indirectly.}, } @article {pmid37202876, year = {2023}, author = {Wira Septama, A and Arvia Chiara, M and Turnip, G and Nur Tasfiyati, A and Triana Dewi, R and Anggrainy Sianipar, E and Jaisi, A}, title = {Essential Oil of Zingiber cassumunar Roxb. and Zingiber officinale Rosc.: A Comparative Study on Chemical Constituents, Antibacterial Activity, Biofilm Formation, and Inhibition of Pseudomonas aeruginosa Quorum Sensing System.}, journal = {Chemistry & biodiversity}, volume = {20}, number = {6}, pages = {e202201205}, doi = {10.1002/cbdv.202201205}, pmid = {37202876}, issn = {1612-1880}, support = {//Rumah Program Vaksin Obat-OR Kesehatan, National Research and Innovation Agency (BRIN), Indonesia/ ; }, abstract = {Pseudomonas aeruginosa can regulate its pathogenicity via quorum sensing (QS) system. Zingiber cassumunar and Z. officinale have been used for the treatment of infectious diseases. The study aimed to evaluate and compare the chemical constituents, antibacterial, and QS inhibitor of Z. cassumunar essential oils (ZCEO) and Z. officinale essential oils (ZOEO). The chemical constituent was analysed using GC/MS. Broth microdilution and spectrophotometry analysis were used to evaluate their antibacterial and QS inhibitor activities. The main constituent of ZOEO with percent composition above 6 % (α-curcumene, α-zingiberene, β-sesquiphellandrene, and β-bisabolene, α-citral, and α-farnesene) were exist in a very minimal percentage less than 0.7 % in Z. cassumunar. All major components of ZCEO with percentages higher than 5 % (terpinen-4-ol, sabinene, γ-terpinene) were present in low proportion (<1.18 %) in Z. officinale. ZCEO demonstrated moderate antibacterial activity against P. aeruginosa. The combination of ZCEO and tetracycline showed a synergistic effect (FICI of 0.5). ZCEO exhibited strong activity in inhibiting biofilm formation. ZCEO at 1 / 2 ${{ 1/2 } } $ MIC (62.5 μg/mL) was able to reduce pyoverdine, pyocyanin, and proteolytic activity. This is the first report on the activity of ZCEO in the inhibition of P. aeruginosa QS system and it may be used to control the pathogenicity of P. aeruginosa.}, } @article {pmid37202810, year = {2023}, author = {Wang, G and Yin, X and Feng, Z and Chen, C and Chen, D and Wu, B and Liu, C and Morel, JL and Jiang, Y and Yu, H and He, H and Chao, Y and Tang, Y and Qiu, R and Wang, S}, title = {Novel biological aqua crust enhances in situ metal(loid) bioremediation driven by phototrophic/diazotrophic biofilm.}, journal = {Microbiome}, volume = {11}, number = {1}, pages = {110}, pmid = {37202810}, issn = {2049-2618}, mesh = {*Ecosystem ; Biodegradation, Environmental ; *Environmental Monitoring ; Biofilms ; }, abstract = {BACKGROUND: Understanding the ecological and environmental functions of phototrophic biofilms in the biological crust is crucial for improving metal(loid) (e.g. Cd, As) bioremediation in mining ecosystems. In this study, in combination with metal(loid) monitoring and metagenomic analysis, we systematically evaluated the effect of biofilm in a novel biological aqua crust (biogenic aqua crust-BAC) on in situ metal(loid) bioremediation of a representative Pb/Zn tailing pond.

RESULTS: We observed strong accumulation of potentially bioavailable metal(loid)s and visible phototrophic biofilms in the BAC. Furthermore, dominating taxa Leptolyngbyaceae (10.2-10.4%, Cyanobacteria) and Cytophagales (12.3-22.1%, Bacteroidota) were enriched in biofilm. Along with predominant heterotrophs (e.g. Cytophagales sp.) as well as diazotrophs (e.g. Hyphomonadaceae sp.), autotrophs/diazotrophs (e.g. Leptolyngbyaceae sp.) in phototrophic biofilm enriched the genes encoding extracellular peptidase (e.g. family S9, S1), CAZymes (e.g. CBM50, GT2) and biofilm formation (e.g. OmpR, CRP and LuxS), thus enhancing the capacity of nutrient accumulation and metal(loid) bioremediation in BAC system.

CONCLUSIONS: Our study demonstrated that a phototrophic/diazotrophic biofilm constitutes the structured communities containing specific autotrophs (e.g. Leptolyngbyaceae sp.) and heterotrophs (e.g. Cytophagales sp.), which effectively control metal(loid) and nutrient input using solar energy in aquatic environments. Elucidation of the mechanisms of biofilm formation coupled with metal(loid) immobilization in BAC expands the fundamental understanding of the geochemical fate of metal(loid)s, which may be harnessed to enhance in situ metal(loid) bioremediation in the aquatic ecosystem of the mining area. Video Abstract.}, } @article {pmid37202425, year = {2023}, author = {He, L and Lv, H and Wang, Y and Jiang, F and Liu, Q and Zhang, F and Wang, H and Shen, H and Otto, M and Li, M}, title = {Antibiotic treatment can exacerbate biofilm-associated infection by promoting quorum cheater development.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {26}, pmid = {37202425}, issn = {2055-5008}, support = {ZIA AI001080/ImNIH/Intramural NIH HHS/United States ; }, mesh = {Animals ; Humans ; *Biofilms ; Quorum Sensing/genetics ; Staphylococcus ; Staphylococcus aureus/genetics ; *Staphylococcal Infections/drug therapy/microbiology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Quorum cheating, a socio-microbiological process that is based on mutations in cell density-sensing (quorum-sensing) systems, has emerged as an important contributor to biofilm-associated infection in the leading human pathogen Staphylococcus aureus. This is because inactivation of the staphylococcal Agr quorum-sensing system leads to pronounced biofilm formation, increasing resistance to antibiotics and immune defense mechanisms. Since biofilm infections in the clinic usually progress under antibiotic treatment, we here investigated whether such treatment promotes biofilm infection via the promotion of quorum cheating. Quorum cheater development was stimulated by several antibiotics used in the treatment of staphylococcal biofilm infections more strongly in biofilm than in the planktonic mode of growth. Sub-inhibitory concentrations of levofloxacin and vancomycin were investigated for their impact on biofilm-associated (subcutaneous catheter-associated and prosthetic joint-associated infection), where in contrast to a non-biofilm-associated subcutaneous skin infection model, a significant increase of the bacterial load and development of agr mutants was observed. Our results directly demonstrate the development of Agr dysfunctionality in animal biofilm-associated infection models and reveal that inappropriate antibiotic treatment can be counterproductive for such infections as it promotes quorum cheating and the associated development of biofilms.}, } @article {pmid37201119, year = {2023}, author = {Fernández-Barat, L and Vázquez Burgos, N and Alcaraz, V and Bueno-Freire, L and López-Aladid, R and Cabrera, R and Gabarrús, A and Palomeque, A and Oscanoa, P and Ceccato, A and Motos, A and Amaro, R and Bernardi, T and Provot, C and Soler-Comas, A and Muñoz, L and Vila, J and Torres, A}, title = {The value of biofilm testing to guide antimicrobial stewardship in chronic respiratory diseases.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1142274}, pmid = {37201119}, issn = {2235-2988}, mesh = {Humans ; *Antimicrobial Stewardship ; Biofilms ; Ciprofloxacin/pharmacology/therapeutic use ; Phenotype ; *Respiratory Tract Diseases ; Pseudomonas aeruginosa/genetics ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Pseudomonas Infections/diagnosis/drug therapy/microbiology ; }, abstract = {INTRODUCTION: Biofilm production is an important yet currently overlooked aspect of diagnostic microbiology that has implications for antimicrobial stewardship. In this study, we aimed to validate and identify additional applications of the BioFilm Ring Test® (BRT) for Pseudomonas aeruginosa (PA) isolates from patients with bronchiectasis (BE).

MATERIALS AND METHODS: Sputa were collected from BE patients who had at least one PA positive culture in the previous year. We processed the sputa to isolate both mucoid and non-mucoid PA, and determined their susceptibility pattern, mucA gene status, and presence of ciprofloxacin mutations in QRDR genes. The Biofilm production index (BPI) was obtained at 5 and 24 hours. Biofilms were imaged using Gram staining.

RESULTS: We collected 69 PA isolates, including 33 mucoid and 36 non-mucoid. A BPI value below 14.75 at 5 hours predicted the mucoid PA phenotype with 64% sensitivity and 72% specificity.

CONCLUSION: Overall, our findings suggest that the fitness-cost associated with the mucoid phenotype or ciprofloxacin resistance is shown through a time-dependent BPI profile. The BRT has the potential to reveal biofilm features with clinical implications.}, } @article {pmid37201113, year = {2023}, author = {Takano, T and Kudo, H and Eguchi, S and Matsumoto, A and Oka, K and Yamasaki, Y and Takahashi, M and Koshikawa, T and Takemura, H and Yamagishi, Y and Mikamo, H and Kunishima, H}, title = {Inhibitory effects of vaginal Lactobacilli on Candida albicans growth, hyphal formation, biofilm development, and epithelial cell adhesion.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1113401}, pmid = {37201113}, issn = {2235-2988}, mesh = {Female ; Humans ; *Candida albicans ; Hydrogen Peroxide/pharmacology ; Lactobacillus ; Candida ; *Candidiasis, Vulvovaginal ; Antifungal Agents/pharmacology ; Epithelial Cells ; Biofilms ; }, abstract = {INTRODUCTION: Antifungal agents are not always efficient in resolving vulvovaginal candidiasis (VVC), a common genital infection caused by the overgrowth of Candida spp., including Candida albicans, or in preventing recurrent infections. Although lactobacilli (which are dominant microorganisms constituting healthy human vaginal microbiota) are important barriers against VVC, the Lactobacillus metabolite concentration needed to suppress VVC is unknown.

METHODS: We quantitatively evaluated Lactobacillus metabolite concentrations to determine their effect on Candida spp., including 27 vaginal strains of Lactobacillus crispatus, L. jensenii, L. gasseri, Lacticaseibacillus rhamnosus, and Limosilactobacillus vaginalis, with inhibitory abilities against biofilms of C. albicans clinical isolates.

RESULTS: Lactobacillus culture supernatants suppressed viable fungi by approximately 24%-92% relative to preformed C. albicans biofilms; however, their suppression differed among strains and not species. A moderate negative correlation was found between Lactobacillus lactate production and biofilm formation, but no correlation was observed between hydrogen peroxide production and biofilm formation. Both lactate and hydrogen peroxide were required to suppress C. albicans planktonic cell growth. Lactobacillus strains that significantly inhibited biofilm formation in culture supernatant also inhibited C. albicans adhesion to epithelial cells in an actual live bacterial adhesion competition test.

DISCUSSION: Healthy human microflora and their metabolites may play important roles in the development of new antifungal agent against C. albicans-induced VVC.}, } @article {pmid37199658, year = {2023}, author = {Park, S and Dingemans, J and Sauer, K}, title = {Manganese Acts as an Environmental Inhibitor of Pseudomonas aeruginosa Biofilm Development by Inducing Dispersion and Modulating c-di-GMP and Exopolysaccharide Production via RbdA.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0000323}, doi = {10.1128/jb.00003-23}, pmid = {37199658}, issn = {1098-5530}, abstract = {The opportunistic human pathogen Pseudomonas aeruginosa causes chronic infections that involve multicellular aggregates called biofilms. Biofilm formation is modulated by the host environment and the presence of cues and/or signals, likely affecting the pool of the bacterial second messenger cyclic diguanylate monophosphate (c-di-GMP). The manganese ion Mn[2+] is a divalent metal cation that is essential for pathogenic bacterial survival and replication during the infection in a host organism. In this study, we investigated how Mn[2+] alters P. aeruginosa biofilm formation via the regulation of c-di-GMP levels. Exposure to Mn[2+] was found to temporally enhance attachment but impair subsequent biofilm development, apparent by reduced biofilm biomass accumulation and lack of microcolony formation due to the induction of dispersion. Moreover, exposure to Mn[2+] coincided with reduced production of the exopolysaccharides Psl and Pel, decreased transcriptional abundance of pel and psl, and decreased levels of c-di-GMP. To determine whether the effect of Mn[2+] was linked to the activation of phosphodiesterases (PDEs), we screened several PDE mutants for Mn[2+]-dependent phenotypes (attachment and polysaccharide production) as well as PDE activity. The screen revealed that the PDE RbdA is activated by Mn[2+] and is responsible for Mn[2+]-dependent attachment, inhibition of Psl production, and dispersion. Taken together, our findings suggest Mn[2+] is an environmental inhibitor of P. aeruginosa biofilm development that acts through the PDE RbdA to modulate c-di-GMP levels, thereby impeding polysaccharide production and biofilm formation but enhancing dispersion. IMPORTANCE While diverse environmental conditions such as the availability of metal ions have been shown to affect biofilm development, little is known about the mechanism. Here, we demonstrate that Mn[2+] affects Pseudomonas aeruginosa biofilm development by stimulating phosphodiesterase RbdA activity to reduce the signaling molecule c-di-GMP levels, thereby hindering polysaccharide production and biofilm formation but enhancing dispersion. Our findings demonstrate that Mn[2+] acts as an environmental inhibitor of P. aeruginosa biofilms, further suggesting manganese to be a promising new antibiofilm factor.}, } @article {pmid37197929, year = {2023}, author = {Shin, JY and Kim, MA and Kim, HJ and Neelakantan, P and Yu, MK and Min, KS}, title = {Evaluation of machine-assisted irrigation on removal of intracanal biofilm and extrusion of sodium hypochlorite using a three-dimensionally printed root canal model.}, journal = {Journal of oral science}, volume = {}, number = {}, pages = {}, doi = {10.2334/josnusd.23-0025}, pmid = {37197929}, issn = {1880-4926}, abstract = {PURPOSE: This study aimed to compare the biofilm removal and apical extrusion of sodium hypochlorite (NaOCl) following machine-assisted irrigation using a three-dimensionally (3D) printed dentin-insert model.

METHODS: Multispecies biofilms were formed in a 3D-printed curved root canal model with dentin insert. The model was then placed in a container that was filled with 0.2% agarose gel containing 0.1% m-Cresol purple. Root canals were irrigated with 1% NaOCl using syringe irrigation, sonically agitated (EndoActivator or EDDY) or ultrasonically activated (Endosonic Blue) irrigation. Samples were photographed and the color-changed area was measured. Biofilm removal was assessed using colony-forming unit counting, confocal laser scanning microscopic analysis and scanning electron microscopic observations. The data were analyzed using one-way ANOVA, followed by Tukey test (P < 0.05).

RESULTS: EDDY and Endosonic Blue demonstrated significantly greater reduction of biofilms compared to other groups. No significant differences were observed in the remaining biofilm volume in syringe irrigation and EndoActivator groups. Furthermore, EDDY and Endosonic Blue presented with numerous exposed dentinal tubules. EDDY showed significantly greater NaOCl extrusion compared to other groups.

CONCLUSION: Ultrasonic activation with a small-sized nickel-titanium file irrigation system may be beneficial in intracanal biofilm removal avoiding extrusion of NaOCl beyond the root apex.}, } @article {pmid37197683, year = {2023}, author = {Lin, X and Yin, H and Wang, L and Chen, Y and Zhao, F and Pu, Y and Tang, X}, title = {Study of a three-dimensional biofilm-electrode reactor (3D-BER) that combined heterotrophic and autotrophic denitrification (HAD) to remove nitrate from water.}, journal = {RSC advances}, volume = {13}, number = {21}, pages = {14675-14684}, pmid = {37197683}, issn = {2046-2069}, abstract = {A three-dimensional biofilm-electrode reactor (3D-BER) that combined heterotrophic and autotrophic denitrification (HAD) was developed to remove nitrate. The denitrification performance of the 3D-BER was evaluated under different experimental conditions, including current intensities (0-80 mA), COD/N ratios (0.5-5), and hydraulic retention times (2-12 h). The results showed that excessive current limited the nitrate removal efficiency. However, a longer hydraulic retention time was not required to achieve a better denitrification effect in the 3D-BER. Moreover, the nitrate could be effectively reduced over a broad range of COD/Ns (1-2.5), and its removal rate peaked at 89% at I = 40 mA, HRT = 8 h, and COD/N = 2. Although the current reduced the diversity of microorganisms in the system, it promoted the growth of dominant species. Nitrification microorganisms were enriched in the reactor, especially Thauera and Hydrogenophaga, which were crucial to the denitrification process. Thus, the combination of autotrophic denitrification and heterotrophic denitrification was promoted by the 3D-BER system to increase the efficiency of nitrogen removal.}, } @article {pmid37196846, year = {2023}, author = {Kim, SY and Kim, SH and Park, SH}, title = {Inactivation of Foodborne Pathogen Biofilm Cells Using a Combination Treatment with Gaseous Chlorine Dioxide and Aerosolized Sanitizers.}, journal = {Journal of food protection}, volume = {86}, number = {7}, pages = {100105}, doi = {10.1016/j.jfp.2023.100105}, pmid = {37196846}, issn = {1944-9097}, abstract = {A biofilm is a three-dimensional microbial community, which is difficult to completely control with a typical sanitizer owing to its complex structure. The aim of this study was to establish a system for the combined treatment of biofilms with 10 ppmv gaseous chlorine dioxide (ClO2) and antimicrobial agents (2% citric acid, 2% hydrogen peroxide [H2O2], and 100 ppm peracetic acid [PAA]), and to investigate the synergistic microbicidal efficacy of the combination treatments to inactivate Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 in biofilms. The antimicrobial agents were aerosolized using a humidifier on top of a chamber to achieve a relative humidity of 90% (within a range of ±2%). While biofilm treatment with the aerosolized antimicrobial agents for 20 min inactivated approximately 1 log CFU/cm[2] (0.72-1.26 log CFU/cm[2]) of the pathogens and the gaseous ClO2 gas treatment for 20 min inactivated <3 log CFU/cm[2] (2.19-2.77 log CFU/cm[2]), combination treatment with citric acid, H2O2, and PAA for 20 min achieved microbial reductions of 2.71-3.79, 4.56-5.12, and 4.45-4.67 log CFU/cm[2,] respectively. Our study demonstrates that foodborne pathogens in biofilms can be inactivated by combining gaseous ClO2 treatment with aerosolized antimicrobial agents. The results of this study provide baseline data for the food industry to help control foodborne pathogens in biofilms on inaccessible surfaces.}, } @article {pmid37196792, year = {2023}, author = {Liang, K and Liu, T and Quan, X}, title = {Simultaneous removal of refractory organic pollutants and nitrogen using electron shuttle suspended biofilm carriers in an integrated hydrolysis/acidification-anoxic/aerobic process.}, journal = {Chemosphere}, volume = {333}, number = {}, pages = {138946}, doi = {10.1016/j.chemosphere.2023.138946}, pmid = {37196792}, issn = {1879-1298}, mesh = {Humans ; *Sewage/chemistry ; Hydrolysis ; Nitrogen/metabolism ; *Environmental Pollutants/metabolism ; Electrons ; Angiotensin Receptor Antagonists/metabolism ; Bioreactors/microbiology ; Angiotensin-Converting Enzyme Inhibitors/metabolism ; Hypoxia ; Bacteria/metabolism ; Biofilms ; Azo Compounds/metabolism ; Hydrogen-Ion Concentration ; Denitrification ; Waste Disposal, Fluid ; }, abstract = {Azo dyes wastewater contains refractory pollutant and nitrogen, which threatens human health and ecological environment when discharged into environment directly. Electron shuttle (ES) is able to participate in the extracellular electron transfer, and thus enhances the removal efficiency of refractory pollutant. However, the continuous dosing of soluble ES would rise operation cost and cause contamination inevitably. In this study, a type of insoluble ES (carbonylated graphene oxide (C-GO)) was developed and melt blended into polyethylene (PE) to prepare novel C-GO-modified suspended carriers. Compared to those of conventional carrier (31.60%), the surface active sites of novel C-GO-modified carrier increased to 52.95%. An integrated hydrolysis/acidification (HA, filled with C-GO-modified carrier) - anoxic/aerobic (AO, filled with clinoptilolite-modified carrier) process was applied to remove azo dye acid red B (ARB) and nitrogen simultaneously. ARB removal efficiency was significantly improved in the reactor filled with C-GO-modified carriers (HA2) compared to the reactor filled with conventional PE carriers (HA1) or activated sludge (HA0). Total nitrogen (TN) removal efficiency of the proposed process increased by 25.95-32.64% compared to the reactor filled with activated sludge. Moreover, the intermediates of ARB were identified by liquid chromatograph-mass spectrometer (LC-MS), and the degradation pathway of ARB through ES was proposed. C-GO-modified carriers induced ARB-removal-related bacterial enrichment (such as Chloroflexi, Lactivibrio, Longilinea, Bacteroidales and Anaerolineaceae). Besides, the relative abundance of denitrifiers and nitrifiers in the AO reactor filled with clinoptilolite-modified carrier was increased by 11.60% compared with activated sludge. Copy numbers of genes related to membrane transport, carbon/energy metabolism and nitrogen metabolism increased significantly on the surface-modified carriers. This study proposed an efficient approach for simultaneous azo dyes and nitrogen removal, showing potential in actual application.}, } @article {pmid37196686, year = {2023}, author = {Daabash, R and Alqahtani, MQ and Price, RB and Alshabib, A and Niazy, A and Alshaafi, MM}, title = {Surface properties and Streptococcus mutans biofilm adhesion of ion-releasing resin-based composite materials.}, journal = {Journal of dentistry}, volume = {134}, number = {}, pages = {104549}, doi = {10.1016/j.jdent.2023.104549}, pmid = {37196686}, issn = {1879-176X}, mesh = {*Streptococcus mutans ; *Composite Resins/pharmacology ; Materials Testing ; Dental Materials/pharmacology ; Biofilms ; Bacterial Adhesion ; Surface Properties ; Water ; }, abstract = {OBJECTIVE: To evaluate the adhesion of Streptococcus mutans (S. mutans) and related surface properties of ion-releasing resin-based composite (RBC) restorative materials.

METHODS: Two ion-releasing RBCs, Activa (ACT) and Cention-N (CN), were compared to a conventional RBC (Z350) and a resin-modified glass ionomer cement (Fuji-II-LC). Ten disk-shaped specimens were fabricated for each material (n = 40). After standardized surface polishing procedure, the surface properties of the specimens were evaluated using surface roughness measurements by a profilometer and hydrophobicity using water contact angle measurements. To assess bacterial adhesion, the number of S. mutans bacteria was calculated from colony-forming units (CFU). Confocal laser scanning microscope analysis was done for qualitative & quantitative assessment. The data were analyzed using One-way ANOVA followed by Tukey's post-hoc test to compare the mean values of surface roughness, water contact angle and CFU values. To compare the mean dead cell percentage Kruskal-Wallis rank test and Conover test were used. A p-value of ≤ 0.05 was used to report the statistical significance.

RESULTS: Z350 and ACT had the smoothest surfaces, followed by CN, and the roughest surface was seen in FUJI-II-LC. The lowest water contact angles were seen in CN, and Z350, and the highest were in ACT. S. mutans counts were the highest in ACT and the lowest in Z350 and CN. CN and Fuji-II-LC registered the highest percentage of dead bacterial cells, while the lowest were in ACT.

SIGNIFICANCE: Surface properties did not significantly influence bacterial adhesion. More S. mutans bacteria accumulated on ACT than on the nanofilled composite and on CN. CN had antibacterial effects against Streptococcus mutans biofilms.}, } @article {pmid37196464, year = {2023}, author = {Wang, J and Wu, J and Li, J and Kong, R and Li, X and Wang, X}, title = {Simulation of various biofilm fractal morphologies by agent-based model.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {227}, number = {}, pages = {113352}, doi = {10.1016/j.colsurfb.2023.113352}, pmid = {37196464}, issn = {1873-4367}, mesh = {*Fractals ; *Biofilms ; Extracellular Polymeric Substance Matrix ; Extracellular Matrix/chemistry ; Polymers/chemistry ; Bacteria ; }, abstract = {Biofilms are clusters of bacteria wrapped in extracellular matrix and polymers. The study of biofilm morphological transformation has been around for a long time and has attracted widespread attention. In this paper, we present a model for biofilm growth based on the interaction force, in which bacteria are treated as tiny particles and locations of particles are updated by calculating the repulsive forces among particles. We adapt a continuity equation to indicate nutrient concentration variation in the substrate. Based on the above, we study the morphological transformation of biofilms. We find that nutrient concentration and nutrient diffusion rate dominate different biofilm morphological transition processes, in which biofilms would grow into fractal morphology under the conditions of low nutrient concentration and nutrient diffusivity. At the same time, we expand our model by introducing a second particle to mimic extracellular polymeric substances (EPS) in biofilms. We find that the interaction between different particles can lead to phase separation patterns between cells and EPSs, and the adhesion effect of EPS can attenuate this phenomenon. In contrast to single particle system models, branches are inhibited due to EPS filling in dual particle system models, and this invalidation is boosted by the enhancement of the depletion effect.}, } @article {pmid37196462, year = {2023}, author = {Xu, LC and Ochetto, A and Chen, C and Sun, D and Allcock, HR and Siedlecki, CA}, title = {Surfaces modified with small molecules that interfere with nucleotide signaling reduce Staphylococcus epidermidis biofilm and increase the efficacy of ciprofloxacin.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {227}, number = {}, pages = {113345}, doi = {10.1016/j.colsurfb.2023.113345}, pmid = {37196462}, issn = {1873-4367}, mesh = {*Ciprofloxacin/pharmacology ; *Staphylococcus epidermidis ; Nucleotides ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Cyclic GMP/metabolism/pharmacology ; Biocompatible Materials/pharmacology ; Adenosine Monophosphate ; }, abstract = {Staphylococcus epidermidis are common bacteria associated with biofilm related infections on implanted medical devices. Antibiotics are often used in combating such infections, but they may lose their efficacy in the presence of biofilms. Bacterial intracellular nucleotide second messenger signaling plays an important role in biofilm formation, and interference with the nucleotide signaling pathways provides a possible way to control biofilm formation and to increase biofilm susceptibility to antibiotic therapy. This study synthesized small molecule derivates of 4-arylazo-3,5-diamino-1 H-pyrazole (named as SP02 and SP03) and found these molecules inhibited S. epidermidis biofilm formation and induced biofilm dispersal. Analysis of bacterial nucleotide signaling molecules showed that both SP02 and SP03 significantly reduced cyclic dimeric adenosine monophosphate (c-di-AMP) levels in S. epidermidis at doses as low as 25 µM while having significant effects on multiple nucleotides signaling including cyclic dimeric guanosine monophosphate (c-di-GMP), c-di-AMP, and cyclic adenosine monophosphate (cAMP) at high doses (100 µM or greater). We then tethered these small molecules to polyurethane (PU) biomaterial surfaces and investigated biofilm formation on the modified surfaces. Results showed that the modified surfaces significantly inhibited biofilm formation during 24 h and 7-day incubations. The antibiotic ciprofloxacin was used to treat these biofilms and the efficacy of the antibiotic (2 µg/mL) was found to increase from 94.8% on unmodified PU surfaces to > 99.9% on both SP02 and SP03 modified surfaces (>3 log units). Results demonstrated the feasibility of tethering small molecules that interfere with nucleotide signaling onto polymeric biomaterial surfaces and in a way that interrupts biofilm formation and increases antibiotic efficacy for S. epidermidis infections.}, } @article {pmid37196354, year = {2023}, author = {Wang, H and Fu, Y and Du, S and Liu, P and Ren, J and Liu, Y and Tao, J and Zhang, L and Zhu, J}, title = {Mechanically Robust Dissolving Microneedles Made of Supramolecular Photosensitizers for Effective Photodynamic Bacterial Biofilm Elimination.}, journal = {ACS applied materials & interfaces}, volume = {15}, number = {21}, pages = {25417-25426}, doi = {10.1021/acsami.3c03614}, pmid = {37196354}, issn = {1944-8252}, mesh = {Humans ; Photosensitizing Agents/pharmacology/therapeutic use ; *Photochemotherapy ; Biofilms ; Extracellular Polymeric Substance Matrix ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Staphylococcal Infections/drug therapy ; }, abstract = {Bacterial biofilms pose severe threats to public health worldwide and are intractable by conventional antibiotic treatment. Antimicrobial photodynamic therapy (PDT) is emerging as a promising strategy for eradicating biofilms by virtue of low invasiveness, broad-spectrum antibacterial activity, and nondrug resistance. However, its practical efficacy is impeded by the low water solubility, severe aggregation, and poor penetration of photosensitizers (PSs) into the dense extracellular polymeric substances (EPS) of biofilms. Herein, we develop a dissolving microneedle (DMN) patch composed of a sulfobutylether-β-cyclodextrin (SCD)/tetra(4-pyridyl)-porphine (TPyP) supramolecular PS for enhanced biofilm penetration and eradication. The inclusion of TPyP into the SCD cavity can drastically inhibit the aggregation of TPyP, thereby allowing for nearly tenfold reactive oxygen species production and high photodynamic antibacterial efficacy. Moreover, the TPyP/SCD-based DMN (TSMN) possesses excellent mechanical performance that can easily pierce the EPS of biofilm with a penetration depth of ∼350 μm, enabling sufficient contact of TPyP with bacteria and optimal photodynamic elimination of bacterial biofilms. Furthermore, TSMN could efficiently eradicate Staphylococcus aureus biofilm infection in vivo with good biosafety. This study offers a promising platform for supramolecular DMN for efficient biofilm elimination and other PDTs.}, } @article {pmid37196016, year = {2023}, author = {Alvarado, M and Gómez-Navajas, JA and Blázquez-Muñoz, MT and Gómez-Molero, E and Berbegal, C and Eraso, E and Kramer, G and De Groot, PWJ}, title = {Integrated post-genomic cell wall analysis reveals floating biofilm formation associated with high expression of flocculins in the pathogen Pichia kudriavzevii.}, journal = {PLoS pathogens}, volume = {19}, number = {5}, pages = {e1011158}, pmid = {37196016}, issn = {1553-7374}, mesh = {*Saccharomyces cerevisiae/metabolism ; *Proteome/analysis ; Proteomics ; Candida albicans/genetics ; Candida/genetics ; Biofilms ; Genomics ; Cell Wall/metabolism ; }, abstract = {The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida species. Its cell wall, a dynamic organelle that is the first point of interaction between pathogen and host, is relatively understudied, and its wall proteome remains unidentified to date. Here, we present an integrated study of the cell wall in P. kudriavzevii. Our comparative genomic studies and experimental data indicate that the general structure of the cell wall in P. kudriavzevii is similar to Saccharomyces cerevisiae and C. albicans and is comprised of β-1,3-glucan, β-1,6-glucan, chitin, and mannoproteins. However, some pronounced differences with C. albicans walls were observed, for instance, higher mannan and protein levels and altered protein mannosylation patterns. Further, despite absence of proteins with high sequence similarity to Candida adhesins, protein structure modeling identified eleven proteins related to flocculins/adhesins in S. cerevisiae or C. albicans. To obtain a proteomic comparison of biofilm and planktonic cells, P. kudriavzevii cells were grown to exponential phase and in static 24-h cultures. Interestingly, the 24-h static cultures of P. kudriavzevii yielded formation of floating biofilm (flor) rather than adherence to polystyrene at the bottom. The proteomic analysis of both conditions identified a total of 33 cell wall proteins. In line with a possible role in flor formation, increased abundance of flocculins, in particular Flo110, was observed in the floating biofilm compared to exponential cells. This study is the first to provide a detailed description of the cell wall in P. kudriavzevii including its cell wall proteome, and paves the way for further investigations on the importance of flor formation and flocculins in the pathogenesis of P. kudriavzevii.}, } @article {pmid37195208, year = {2023}, author = {Howard, MK and Miller, KR and Sohn, BS and Ryan, JJ and Xu, A and Jackrel, ME}, title = {Probing the drivers of Staphylococcus aureus biofilm protein amyloidogenesis and disrupting biofilms with engineered protein disaggregases.}, journal = {mBio}, volume = {}, number = {}, pages = {e0058723}, doi = {10.1128/mbio.00587-23}, pmid = {37195208}, issn = {2150-7511}, support = {R35 GM128772/GM/NIGMS NIH HHS/United States ; }, abstract = {Phenol-soluble modulins (PSMs) are the primary proteinaceous component of Staphylococcus aureus biofilms. Residence in the protective environment of biofilms allows bacteria to rapidly evolve and acquire antimicrobial resistance, which can lead to persistent infections such as those caused by methicillin-resistant S. aureus (MRSA). In their soluble form, PSMs hinder the immune response of the host and can increase the virulence potential of MRSA. PSMs also self-assemble into insoluble functional amyloids that contribute to the structural scaffold of biofilms. The specific roles of PSM peptides in biofilms remain poorly understood. Here, we report the development of a genetically tractable yeast model system for studying the properties of PSMα peptides. Expression of PSMα peptides in yeast drives the formation of toxic insoluble aggregates that adopt vesicle-like structures. Using this system, we probed the molecular drivers of PSMα aggregation to delineate key similarities and differences among the PSMs and identified a crucial residue that drives PSM features. Biofilms are a major public health threat; thus, biofilm disruption is a key goal. To solubilize aggregates comprised of a diverse range of amyloid and amyloid-like species, we have developed engineered variants of Hsp104, a hexameric AAA+ protein disaggregase from yeast. Here, we demonstrate that potentiated Hsp104 variants counter the toxicity and aggregation of PSMα peptides. Further, we demonstrate that a potentiated Hsp104 variant can drive the disassembly of preformed S. aureus biofilms. We suggest that this new yeast model can be a powerful platform for screening for agents that disrupt PSM aggregation and that Hsp104 disaggregases could be a promising tool for the safe enzymatic disruption of biofilms.}, } @article {pmid37195016, year = {2023}, author = {Visser, JA and Yager, D and Chambers, SA and Lim, JY and Cao, X and Cegelski, L}, title = {Nordihydroguaiaretic Acid (NDGA) Inhibits CsgA Polymerization, Bacterial Amyloid Biogenesis, and Biofilm Formation.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {}, number = {}, pages = {e202300266}, doi = {10.1002/cbic.202300266}, pmid = {37195016}, issn = {1439-7633}, abstract = {Escherichia coli and other Enterobacteriaceae thrive in robust biofilm communities through the coproduction of curli amyloid fibers and phosphoethanolamine cellulose. Curli promote adhesion to abiotic surfaces and plant and human host tissues and are associated with pathogenesis in urinary tract infection and foodborne illness. As amyloid, curli production in the host has also been implicated in the pathogenesis of neurodegenerative diseases. We report that the natural product nordihydroguaiaretic acid (NDGA) is effective as a curlicide in E. coli. NDGA prevents CsgA polymerization in vitro in a dose-dependent manner. NDGA selectively inhibits cellassociated curli assembly in E. coli and inhibits biofilm formation among uropathogenic E. coli in a curli-specific manner. More broadly, our work emphasizes the ability to evaluate and identify bioactive amyloid assembly inhibitors using the powerful gene-directed amyloid biogenesis machinery in E. coli.}, } @article {pmid37193875, year = {2023}, author = {Wang, Y and Liu, H and Geng, F and Yang, P and Lü, J and Li, X}, title = {Label-free analysis of biofilm phenotypes by infrared micro- and correlation spectroscopy.}, journal = {Analytical and bioanalytical chemistry}, volume = {}, number = {}, pages = {}, pmid = {37193875}, issn = {1618-2650}, support = {2021XDRHXMPT28//Yantai Region and College Integration Development Project/ ; JNL-2022021B//Research Project of Jinan Microecological Biomedicine Shandong Laboratory/ ; }, abstract = {The methodology development for deeply describing the complex biofilm phenotypes is an urgent demand for understanding their basic biology and the central clinic relevance. Here, we developed an infrared microspectroscopy-based method for the quantitative evaluation and description of biofilm phenotypic characteristics by calculating the spectral similarity of the infrared data. Using this approach, we revealed the phenotypic variation during the biofilm formation process and biofilm heterogeneity between two E. coli strains. Two-dimensional correlation spectroscopy was further combined to deeply investigate the biochemical component evolution sequences during E. coli biofilm formation and revealed the first-order of the polysaccharide molecules change, expanding new opportunities for infrared microspectroscopy in revealing molecule evolution in the biofilm formation. This novel development offers a label-free optical toolkit for the bioanalytical analysis of biofilm phenotypes but also paves the way for screening the drugs to modulate the structure and ecology of biofilm microbiome.}, } @article {pmid37193303, year = {2023}, author = {Mao, Y and Liu, P and Chen, H and Wang, Y and Li, C and Wang, Q}, title = {Baicalein Inhibits the Staphylococcus aureus Biofilm and the LuxS/AI-2 System in vitro.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {2861-2882}, pmid = {37193303}, issn = {1178-6973}, abstract = {INTRODUCTION: Staphylococcus aureus (S. aureus) is a common cause of mastitis in dairy cows, a condition that has a significant economic impact. S. aureus displays quorum sensing (QS) system-controlled virulence characteristics, like biofilm formation, that make therapy challenging. In order to effectively combat S. aureus, one potential technique is to interfere with quorum sensing.

METHODS: This study evaluated the effects of different Baicalin (BAI) concentrations on the growth and the biofilm of S. aureus isolates, including the biofilm formation and mature biofilm clearance. The binding activity of BAI to LuxS was verified by molecular docking and kinetic simulations. The secondary structure of LuxS in the formulations was characterized using fluorescence quenching and Fourier transform infrared (FTIR) spectroscopy. Additionally, using fluorescence quantitative PCR, the impact of BAI on the transcript levels of the luxS and biofilm-related genes was investigated. The impact of BAI on LuxS at the level of protein expression was also confirmed by a Western blotting investigation.

RESULTS: According to the docking experiments, they were able to engage with the amino acid residues in LuxS and BAI through hydrogen bonding. The results of molecular dynamics simulations and the binding free energy also confirmed the stability of the complex and supported the experimental results. BAI showed weak inhibitory activity against S. aureus but significantly reduced biofilm formation and disrupted mature biofilms. BAI also downregulated luxS and biofilm-associated genes' mRNA expression. Successful binding was confirmed using fluorescence quenching and FTIR.

DISCUSSION: We thus report that BAI inhibits the S. aureus LuxS/AI-2 system for the first time, which raises the possibility that BAI could be employed as a possible antimicrobial drug to treat S. aureus strain-caused biofilms.}, } @article {pmid37192897, year = {2023}, author = {Xia, F and Tao, X and Wang, H and Shui, J and Min, C and Xia, Y and Li, J and Tang, M and Liu, Z and Hu, Y and Luo, H and Zou, M}, title = {Biosynthesis of Silver Nanoparticles Using the Biofilm Supernatant of Pseudomonas aeruginosa PA75 and Evaluation of Their Antibacterial, Antibiofilm, and Antitumor Activities.}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {2485-2502}, pmid = {37192897}, issn = {1178-2013}, mesh = {Colistin/pharmacology ; Pseudomonas aeruginosa ; Silver/pharmacology/chemistry ; *Methicillin-Resistant Staphylococcus aureus ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/chemistry ; Biofilms ; }, abstract = {PURPOSE: As an under-explored biomaterial, bacterial biofilms have a wide range of applications in the green synthesis of nanomaterials. The biofilm supernatant of Pseudomonas aeruginosa PA75 was used to synthesize novel silver nanoparticles (AgNPs). BF75-AgNPs were found to possess several biological properties.

METHODS: In this study, we biosynthesized BF75-AgNPs using biofilm supernatant as the reducing agent, stabilizer, and dispersant and investigated their biopotential in terms of antibacterial, antibiofilm, and antitumor activities.

RESULTS: The synthesized BF75-AgNPs demonstrated a typical face-centered cubic crystal structure; they were well dispersed; and they were spherical with a size of 13.899 ± 4.036 nm. The average zeta potential of the BF75-AgNPs was -31.0 ± 8.1 mV. The BF75-AgNPs exhibited strong antibacterial activities against the methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase Escherichia coli (ESBL-EC), extensively drug-resistant Klebsiella pneumoniae (XDR-KP), and carbapenem-resistant Pseudomonas aeruginosa (CR-PA). Moreover, the BF75-AgNPs had a strong bactericidal effect on XDR-KP at 1/2 × MIC, and the expression level of reactive oxygen species (ROS) in bacteria was significantly increased. A synergistic effect was observed when the BF75-AgNPs and colistin were used for the co-treatment of two colistin-resistant XDR-KP strains, with fractional inhibitory concentration index (FICI) values of 0.281 and 0.187, respectively. Furthermore, the BF75-AgNPs demonstrated a strong biofilm inhibition activity and mature biofilm bactericidal activity against XDR-KP. The BF75-AgNPs also exhibited a strong antitumor activity against melanoma cells and low cytotoxicity against normal epidermal cells. In addition, the BF75-AgNPs increased the proportion of apoptotic cells in two melanoma cell lines, and the proportion of late apoptotic cells increased with BF75-AgNP concentration.

CONCLUSION: This study suggests that BF75-AgNPs synthesized from biofilm supernatant have broad prospects for antibacterial, antibiofilm, and antitumor applications.}, } @article {pmid37192894, year = {2023}, author = {Tong, F and Wang, P and Chen, Z and Liu, Y and Wang, L and Guo, J and Li, Z and Cai, H and Wei, J}, title = {Combined Ferromagnetic Nanoparticles for Effective Periodontal Biofilm Eradication in Rat Model.}, journal = {International journal of nanomedicine}, volume = {18}, number = {}, pages = {2371-2388}, pmid = {37192894}, issn = {1178-2013}, mesh = {Rats ; Animals ; Minocycline/pharmacology ; Anti-Bacterial Agents/chemistry ; Biofilms ; *Nanoparticles/chemistry ; *Periodontitis/drug therapy ; }, abstract = {INTRODUCTION: The critical challenge for periodontitis therapy is thoroughly eliminating the dental plaque biofilm, particularly penetrating the deep periodontal tissue. Regular therapeutic strategies are insufficient to penetrate the plaque without disturbing the commensal microflora of the oral cavity. Here, we constructed a Fe3O4 magnetic nanoparticle loading minocycline (FPM NPs) to penetrate the biofilm physically and effectively eliminate periodontal biofilm.

METHODS: In order to penetrate and remove the biofilm effectively, Fe3O4 magnetic nanoparticles were modified with minocycline using a co-precipitation method. The particle size and dispersion of the nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The antibacterial effects were examined to verify the magnetic targeting of FPM NPs. Confocal laser scanning microscopy was employed to check the effect of FPM + MF and develop the best FPM NPs treatment strategy. Additionally, the therapeutic effect of FPM NPs was investigated in periodontitis rat models. The expression of IL-1β, IL-6, and TNF-α in periodontal tissues was measured by qRT-PCR and Western blot.

RESULTS: The multifunctional nanoparticles exhibited intense anti-biofilm activity and good biocompatibility. The magnetic forces could pull FMP NPs against the biofilm mass and kill bacteria deep in the biofilms both in vivo and in vitro. The integrity of the bacterial biofilm is disrupted under the motivation of the magnetic field, allowing for improved drug penetration and antibacterial performance. The periodontal inflammation recovered well after FPM NPs treatment in rat models. Furthermore, FPM NPs could be monitored in real-time and have magnetic targeting potentials.

CONCLUSION: FPM NPs exhibit good chemical stability and biocompatibility. The novel nanoparticle presents a new approach for treating periodontitis and provides experimental support for using magnetic-targeted nanoparticles in clinic applications.}, } @article {pmid37191582, year = {2023}, author = {Nassar, R and Nassar, M and Senok, A and Williams, D}, title = {Phytic Acid Demonstrates Rapid Antibiofilm Activity and Inhibits Biofilm Formation When Used as a Surface Conditioning Agent.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0026723}, pmid = {37191582}, issn = {2165-0497}, mesh = {*Phytic Acid/pharmacology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology ; Candida albicans ; Biofilms ; }, abstract = {Root canal infections are associated with biofilms and are treated with chemical irrigants with a high success rate. However, treatment failure does arise, which is attributed primarily to resistance exhibited by biofilms. Currently used irrigants in root canal treatment have disadvantages, and there is therefore a need for more biocompatible alternatives with antibiofilm properties to reduce root canal treatment failure and complications. The aim of this study was to evaluate the in vitro antibiofilm properties of phytic acid (IP6), which is a potential alternative treatment agent. Single- and dual-species biofilms of Enterococcus faecalis and Candida albicans were developed on the well surfaces of 12-well plates and on hydroxyapatite (HA) coupons, and then exposed to IP6. In addition, selected HA coupons were preconditioned with IP6 before biofilm development. IP6 demonstrated bactericidal effects and altered the metabolic activity of biofilm cells. Confocal laser-scanning microscopy showed that IP6 caused significant and rapid reduction in live biofilm cells. At sublethal concentrations, IP6 did not alter the expression of tested virulence genes except for C. albicans hwp1, the expression of which was upregulated but not reflected by a change in hyphal transformation. IP6-preconditioned HA coupons led to extensive inhibition of dual-species biofilm formation. The results of this study highlight for the first time the antibiofilm inhibitory properties of IP6 and the potential for its exploitation in several clinical applications. IMPORTANCE Root canal infections are biofilm associated, and despite mechanical and chemical treatment procedures, infection recurrence occurs, and this is likely due to the high tolerance of associated biofilms to antimicrobials. The currently used treatment agents have several disadvantages, which necessitates the search for new improved agents. In this study, the natural chemical phytic acid was found to exhibit antibiofilm activity against established mono and dual mature biofilms over a short contact time. Most importantly, phytic acid was found to cause significant inhibition of dual-species biofilm formation when used as a surface preconditioning agent. The findings of this study identified a novel use of phytic acid as a potential antibiofilm agent that can be used in several clinical applications.}, } @article {pmid37191545, year = {2023}, author = {Silva-Rohwer, AR and Held, K and Yakhnin, H and Babitzke, P and Vadyvaloo, V}, title = {CsrA-Mediated Translational Activation of the hmsE mRNA Enhances HmsD-Dependent C-di-GMP-Enabled Biofilm Production in Yersinia pestis.}, journal = {Journal of bacteriology}, volume = {}, number = {}, pages = {e0010523}, doi = {10.1128/jb.00105-23}, pmid = {37191545}, issn = {1098-5530}, abstract = {The plague bacterium, Yersinia pestis, forms a biofilm-mediated blockage in the flea foregut that enhances its transmission by fleabite. Biofilm formation is positively controlled by cyclic di-GMP (c-di-GMP), which is synthesized by the diguanylate cyclases (DGC), HmsD and HmsT. While HmsD primarily promotes biofilm-mediated blockage of fleas, HmsT plays a more minor role in this process. HmsD is a component of the HmsCDE tripartite signaling system. HmsC and HmsE posttranslationally inhibit or activate HmsD, respectively. HmsT-dependent c-di-GMP levels and biofilm formation are positively regulated by the RNA-binding protein CsrA. In this study we determined whether CsrA positively regulates HmsD-dependent biofilm formation through interactions with the hmsE mRNA. Gel mobility shift assays determined that CsrA binds specifically to the hmsE transcript. RNase T1 footprint assays identified a single CsrA binding site and CsrA-induced structural changes in the hmsE leader region. Translational activation of the hmsE mRNA was confirmed in vivo using plasmid-encoded inducible translational fusion reporters and by HmsE protein expression studies. Furthermore, mutation of the CsrA binding site in the hmsE transcript significantly reduced HmsD-dependent biofilm formation. These results suggest that CsrA binding leads to structural changes in the hmsE mRNA that enhance its translation to enable increased HmsD-dependent biofilm formation. Given the requisite function of HmsD in biofilm-mediated flea blockage, this CsrA-dependent increase in HmsD activity underscores that complex and conditionally defined modulation of c-di-GMP synthesis within the flea gut is required for Y. pestis transmission. IMPORTANCE Mutations enhancing c-di-GMP biosynthesis drove the evolution of Y. pestis to flea-borne transmissibility. c-di-GMP-dependent biofilm-mediated blockage of the flea foregut enables regurgitative transmission of Y. pestis by fleabite. The Y. pestis diguanylate cyclases (DGC), HmsT and HmsD, which synthesize c-di-GMP, play significant roles in transmission. Several regulatory proteins involved in environmental sensing, as well as signal transduction and response regulation, tightly control DGC function. An example is CsrA, a global posttranscriptional regulator that modulates carbon metabolism and biofilm formation. CsrA integrates alternative carbon usage metabolism cues to activate c-di-GMP biosynthesis through HmsT. Here, we demonstrated that CsrA additionally activates hmsE translation to promote c-di-GMP biosynthesis through HmsD. This emphasizes that a highly evolved regulatory network controls c-di-GMP synthesis and Y. pestis transmission.}, } @article {pmid37191458, year = {2023}, author = {Shaghayegh, G and Cooksley, C and Bouras, G and Nepal, R and Houtak, G and Panchatcharam, BS and Fenix, KA and Psaltis, AJ and Wormald, PJ and Vreugde, S}, title = {Staphylococcus aureus biofilm properties and chronic rhinosinusitis severity scores correlate positively with total CD4+ T-cell frequencies and inversely with its Th1, Th17 and regulatory cell frequencies.}, journal = {Immunology}, volume = {}, number = {}, pages = {}, doi = {10.1111/imm.13655}, pmid = {37191458}, issn = {1365-2567}, support = {APP1196832//National Health and Medical Research Council/ ; //The Garnett Passe and Rodney Williams Memorial Foundation/ ; //The Hospital Research Foundation Postgraduate Research Scholarship/ ; //The University of Adelaide Scholarship/ ; }, abstract = {Chronic rhinosinusitis (CRS) represents chronic inflammation of the sinus mucosa characterised by dysfunction of the sinuses' natural defence mechanisms and induction of different inflammatory pathways ranging from a Th1 to a Th2 predominant polarisation. Recalcitrant CRS is associated with Staphylococcus aureus dominant mucosal biofilms; however, S. aureus colonisation of the sinonasal mucosa has also been observed in healthy individuals challenging the significance of S. aureus in CRS pathogenesis. We aimed to investigate the relationship between CRS key inflammatory markers, S. aureus biofilm properties/virulence genes and the severity of the disease. Tissue samples were collected during endoscopic sinus surgery from the ethmoid sinuses of CRS patients with (CRSwNP) and without (CRSsNP) nasal polyps and controls (n = 59). CD3+ T-cell subset frequencies and key inflammatory markers of CD4+ helper T cells were determined using FACS analysis. Sinonasal S. aureus clinical isolates were isolated (n = 26), sequenced and grown into biofilm in vitro, followed by determining their properties, including metabolic activity, biomass, colony-forming units and exoprotein production. Disease severity was assessed using Lund-Mackay radiologic scores, Lund-Kennedy endoscopic scores and SNOT22 quality of life scores. Our results showed that S. aureus biofilm properties and CRS severity scores correlated positively with total CD4+ T-cell frequencies but looking into CD4+ T-cell subsets showed an inverse correlation with Th1 and Th17 cell frequencies. CD4+ T-cell frequencies were higher in patients harbouring lukF.PV-positive S. aureus while its regulatory and Th17 cell subset frequencies were lower in patients carrying sea- and sarT/U-positive S. aureus. Recalcitrant CRS is characterised by increased S. aureus biofilm properties in relation to increased total CD4+ helper T-cell frequencies and reduced frequencies of its Th1, Th17 and regulatory T-cell subsets. These findings offer insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.}, } @article {pmid37190965, year = {2023}, author = {Luan, Y and Wang, Y and Liu, C and Lv, L and Xu, A and Song, Z}, title = {Effects of potassium monopersulfate on nitrification activity and bacterial community structure of sponge biocarrier biofilm in Litopenaeus vannamei aquaculture system.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-22}, doi = {10.1080/09593330.2023.2215455}, pmid = {37190965}, issn = {1479-487X}, abstract = {Effects of potassium monopersulfate (KMPS) on the nitrification activity, aquacultural water quality and bacterial community structure of sponge biocarriers with pre-cultured biofilm (SBBF) were analysed through shaking flask experiments and L. vannamei aquaculture experiments. Changes in the ammonia oxidation rate (AOR) and nitrite oxidation rate (NOR) of SBBF under six KMPS concentration treatments (0 mg/L, 1 mg/L, 2 mg/L, 3 mg/L, 4 mg/L and 5 mg/L) were studied. The results showed that the AOR and NOR of SBBF treated with high concentrations of KMPS (3 mg/L, 4 mg/L and 5 mg/L) were significantly lower than those of the control group (CK) (p < 0.05). However, compared with the first dosing of NH4Cl and NaNO2, the inhibition of AOR and NOR by KMPS on AOR and NOR was weakened after the second and third dosing times. That is, AOR and NOR can recover partially or completely over time. The L. vannamei aquaculture experiment was performed using four concentrations of KMPS (0 mg/L, 2 mg/L, 4 mg/L and 8 mg/L). The results showed that with increasing KMPS dosage, the average and peak concentrations of NH4[+]-N and NO2[-]-N in each treatment significantly increased (P <0.05), and the final body weight of shrimp significantly decreased (P <0.05). Furthermore the highest dose (8.0 mg/L) of KMPS reduced the survival rate by 9.33% compared to the CK. High-throughput sequencing analysis of the biofilm structure showed that the relative abundances of Nitrospirota, Nitrosomonas and Nitrococcus, which are related to nitrogen cycling, and beneficial bacteria including Firmicutes and Bacilli decreased with the addition of KMPS (p<0.05).}, } @article {pmid37189223, year = {2023}, author = {Sun, H and Si, F and Zhao, X and Li, F and Qi, G}, title = {The cellular redox state in Bacillus amyloliquefaciens WH1 affects biofilm formation indirectly in a surfactant direct manner.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300064}, pmid = {37189223}, issn = {1521-4028}, support = {31870030//National Natural Science Foundation of China/ ; }, abstract = {Surfactin is a signal to trigger biofilm formation against harsh environments. Generally, harsh environments can result in change of the cellular redox state to induce biofilm formation, but we know little about whether the cellular redox state influences biofilm formation via surfactin. Here, the reductant glucose could reduce surfactin and enhance biofilm formation by a surfactin-indirect way. The oxidant H2 O2 led to a decrease of surfactin accompanying with weakened biofilm formation. Spx and PerR were both necessary for surfactin production and biofilm formation. H2 O2 improved surfactin production but inhibited biofilm formation by a surfactin-indirect manner in Δspx, while it reduced surfactin production without obvious influence on biofilm formation in ΔperR. The ability against H2 O2 stress was enhanced in Δspx, but weakened in ΔperR. Thereby, PerR was favorable for resisting oxidative stress, while Spx played a negative role in this action. Knockout and compensation of rex also supported that the cells could form biofilm by a surfactin-indirect way. Collectively, surfactin is not a unique signal to trigger biofilm formation, and the cellular redox state can influence biofilm formation by a surfactin-direct or -indirect way in Bacillus amyloliquefaciens WH1.}, } @article {pmid37189214, year = {2023}, author = {Harpke, M and Kothe, E}, title = {Biofilm formation in Gram-positives as an answer to combined salt and metal stress.}, journal = {Journal of basic microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1002/jobm.202300149}, pmid = {37189214}, issn = {1521-4028}, support = {USER//Bundesministerium für Bildung und Forschung/ ; 239748522//Deutsche Forschungsgemeinschaft Cluster Balance of the Microverse under Germany' SFB 1127 ChemBioSys/ ; }, abstract = {Biofilm formation can lead to tolerance against stressors like antibiotics, toxic metals, salts, and other environmental contaminants. Halo- and metal-tolerant bacilli and actinomycete strains isolated from a former uranium mining and milling site in Germany were shown to form biofilm in response to salt and metal treatment; specifically, Cs and Sr exposition led to biofilm formation. Since the strains were obtained from soil samples, a more structured environment was tested using expanded clay to provide porous structures resembling the natural environment. There, accumulation of Cs could be shown for Bacillus sp. SB53B, and high Sr accumulation ranging from 75% to 90% was seen with all isolates tested. We could, therefore, show that biofilms in a structured environment like soil will contribute to the water purification obtained by the passage of water through the critical zone of soil, providing an ecosystem benefit that can hardly be overestimated.}, } @article {pmid37188866, year = {2023}, author = {Islam, OK and Islam, I and Saha, O and Rahaman, MM and Sultana, M and Bockmühl, DP and Hossain, MA}, title = {Genomic variability correlates with biofilm phenotypes in multidrug resistant clinical isolates of Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {7867}, pmid = {37188866}, issn = {2045-2322}, mesh = {*Pseudomonas aeruginosa/metabolism ; *Bacterial Proteins/metabolism ; Biofilms ; Phenotype ; Genomics ; }, abstract = {The multifactorial nature of Pseudomonas aeruginosa biofilm development and genomic variabilities implicates its resistance to conventional antimicrobials and virulence. Therefore, genetic determinants need to be extensively studied to block the early steps of biofilm or already formed biofilms. In this study, a total of 20 multidrug resistant (MDR) clinical P. aeruginosa isolates were evaluated for their biofilm forming abilities and related genes. Of the isolates tested, all of them showed surface attachment tendencies in nutrient limiting conditions, and classified as strong (SBF = 45%), moderate (MBF = 30%) and weak (WBF = 25%) biofilm formers. Complete genome sequencing of representative strong (DMC-27b), moderate (DMC-20c) and weak biofilm former (DMC-30b) isolates was performed. Analysis of biofilm related genes in the sequenced genomes revealed that, 80 of the 88 biofilm related genes possess 98-100% sequence identity to the reference PAO1 strain. Complete and partial sequence data of LecB proteins from tested isolates indicate that isolates containing PA14-like LecB sequences produced strong biofilms. All of the 7 pel operon protein coding genes in weak biofilm former isolate 30b showed significant nucleotide sequence variation with other tested isolates, and their corresponding proteins are 99% identical with the pel operon proteins of PA7. Bioinformatics analyses identified divergent sequence and structural features that separate PA7 like pel operon proteins from reference PAO1-like pel operon. Congo red and pellicle forming assays revealed that the sequence and structure variations may have interfered with the Pel production pathway and resulted in impaired Pel production in isolate 30b that has a PA7 like pel operon. Expression analysis also showed that both pelB and lecB genes were about 5 to 6 folds upregulated after 24 h in SBF 27b in comparison with WBF 30b. Our findings indicate significant genomic divergence in biofilm related genes of P. aeruginosa strains that affect their biofilm phenotypes.}, } @article {pmid37187675, year = {2023}, author = {Parga, A and Manoil, D and Brundin, M and Otero, A and Belibasakis, GN}, title = {Gram-negative quorum sensing signalling enhances biofilm formation and virulence traits in gram-positive pathogen Enterococcus faecalis.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2208901}, pmid = {37187675}, issn = {2000-2297}, abstract = {Acyl-homoserine lactones (AHLs) are typical quorum-sensing molecules of gram-negative bacteria. Recent evidence suggests that AHLs may also affect gram-positives, although knowledge of these interactions remains scarce. Here, we assessed the effect of AHLs on biofilm formation and transcriptional regulations in the gram-positive Enterococcus faecalis. Five E. faecalis strains were investigated herein. Crystal violet was employed to quantify the biomass formed, and confocal microscopy in combination with SYTO9/PI allowed the visualisation of biofilms' structure. The differential expression of 10 genes involved in quorum-sensing, biofilm formation and stress responses was evaluated using reverse-transcription-qPCR. The AHL exposure significantly increased biofilm production in strain ATCC 29212 and two isolates from infected dental roots, UmID4 and UmID5. In strains ATCC 29212 and UmID7, AHLs up-regulated the quorum-sensing genes (fsrC, cylA), the adhesins ace, efaA and asa1, together with the glycosyltransferase epaQ. In strain UmID7, AHL exposure additionally up-regulated two membrane-stress response genes (σ[V], groEL) associated with increased stress-tolerance and virulence. Altogether, our results demonstrate that AHLs promote biofilm formation and up-regulate a transcriptional network involved in virulence and stress tolerance in several E. faecalis strains. These data provide yet-unreported insights into E. faecalis biofilm responses to AHLs, a family of molecules long-considered the monopole of gram-negative signalling.}, } @article {pmid37187373, year = {2023}, author = {Geng, YK and Gu, J and Zhang, X and Lim, ZK and Jiang, Y and Zhang, M and Zhou, Y and Liu, Y}, title = {Multi-parameter control-based operation strategy for mainstream deammonification in an integrated anaerobic biofilm reactor-step feed MBR.}, journal = {Chemosphere}, volume = {333}, number = {}, pages = {138941}, doi = {10.1016/j.chemosphere.2023.138941}, pmid = {37187373}, issn = {1879-1298}, mesh = {*Wastewater ; Sewage/microbiology ; Waste Disposal, Fluid ; Anaerobiosis ; *Ammonium Compounds/analysis ; Bacteria ; Bioreactors/microbiology ; Biofilms ; Nitrogen/analysis ; Nitrites/chemistry ; Oxidation-Reduction ; }, abstract = {The mainstream deammonification of municipal wastewater has been recognized as one of the greatest challenges in wastewater engineering. The conventional activated sludge process has disadvantages of high energy input and sludge production. To tackle this situation, an innovative A-B process, where an anaerobic biofilm reactor (AnBR) functioned as the A stage for energy recovery, and a step-feed membrane bioreactor (MBR) functioned as the B stage for mainstream deammonification, was constructed for carbon-neutral wastewater treatment. For addressing the challenge associated with selective retention of ammonia-oxidizing bacteria (AOB) over nitrite oxidizing bacteria (NOB), a multi-parameter control-based operation strategy was developed with synergistic control of influent COD redistribution, dissolved oxygen (DO) concentration and sludge retention time (SRT) in the innovative AnBR - step-feed MBR system. Results showed that more than 85% of wastewater COD could be removed with the direct production of methane gas in the AnBR. A relatively stable partial nitritation, which is a prerequisite of anammox, was achieved with the successful suppression of NOB, leading to 98% of ammonium-N and 73% of total nitrogen removed. Anammox bacteria could well survive and enrich in the integrated system, and the contribution of anammox to the total nitrogen removal was more than 70% at optimal conditions. Reactions network involved in the nitrogen transformation in the integrated system was further constructed through the mass balance and microbial community structure analyses. Consequently, this study demonstrated a practically feasible process configuration with high operation and control flexibility towards stable mainstream deammonification of municipal wastewater.}, } @article {pmid37186226, year = {2023}, author = {Gill, SP and Snelling, WJ and Dooley, JSG and Ternan, NG and Banat, IM and Arnscheidt, J and Hunter, WR}, title = {Biological and synthetic surfactant exposure increases antimicrobial gene occurrence in a freshwater mixed microbial biofilm environment.}, journal = {MicrobiologyOpen}, volume = {12}, number = {2}, pages = {e1351}, pmid = {37186226}, issn = {2045-8827}, mesh = {RNA, Ribosomal, 16S/genetics ; *Surface-Active Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Fresh Water ; Biofilms ; }, abstract = {Aquatic habitats are particularly susceptible to chemical pollution, such as antimicrobials, from domestic, agricultural, and industrial sources. This has led to the rapid increase of antimicrobial resistance (AMR) gene prevalence. Alternate approaches to counteract pathogenic bacteria are in development including synthetic and biological surfactants such as sodium dodecyl sulfate (SDS) and rhamnolipids. In the aquatic environment, these surfactants may be present as pollutants with the potential to affect biofilm formation and AMR gene occurrence. We tested the effects of rhamnolipid and SDS on aquatic biofilms in a freshwater stream in Northern Ireland. We grew biofilms on contaminant exposure substrates deployed within the stream over 4 weeks. We then extracted DNA and carried out shotgun sequencing using a MinION portable sequencer to determine microbial community composition, with 16S rRNA analyses (64,678 classifiable reads identified), and AMR gene occurrence (81 instances of AMR genes over 9 AMR gene classes) through a metagenomic analysis. There were no significant changes in community composition within all systems; however, biofilm exposed to rhamnolipid had a greater number of unique taxa as compared to SDS treatments and controls. AMR gene prevalence was higher in surfactant-treated biofilms, although not significant, with biofilm exposed to rhamnolipids having the highest presence of AMR genes and classes compared to the control or SDS treatments. Our results suggest that the presence of rhamnolipid encourages an increase in the prevalence of AMR genes in biofilms produced in mixed-use water bodies.}, } @article {pmid37184670, year = {2023}, author = {Hammarén, MM and Luukinen, H and Sillanpää, A and Remans, K and Lapouge, K and Custódio, T and Löw, C and Myllymäki, H and Montonen, T and Seeger, M and Robertson, J and Nyman, TA and Savijoki, K and Parikka, M}, title = {In vitro and ex vivo proteomics of Mycobacterium marinum biofilms and the development of biofilm-binding synthetic nanobodies.}, journal = {mSystems}, volume = {}, number = {}, pages = {e0107322}, doi = {10.1128/msystems.01073-22}, pmid = {37184670}, issn = {2379-5077}, abstract = {The antibiotic-tolerant biofilms present in tuberculous granulomas add an additional layer of complexity when treating mycobacterial infections, including tuberculosis (TB). For a more efficient treatment of TB, the biofilm forms of mycobacteria warrant specific attention. Here, we used Mycobacterium marinum (Mmr) as a biofilm-forming model to identify the abundant proteins covering the biofilm surface. We used biotinylation/streptavidin-based proteomics on the proteins exposed at the Mmr biofilm matrices in vitro to identify 448 proteins and ex vivo proteomics to detect 91 Mmr proteins from the mycobacterial granulomas isolated from adult zebrafish. In vitro and ex vivo proteomics data are available via ProteomeXchange with identifier PXD033425 and PXD039416, respectively. Data comparisons pinpointed the molecular chaperone GroEL2 as the most abundant Mmr protein within the in vitro and ex vivo proteomes, while its paralog, GroEL1, with a known role in biofilm formation, was detected with slightly lower intensity values. To validate the surface exposure of these targets, we created in-house synthetic nanobodies (sybodies) against the two chaperones and identified sybodies that bind the mycobacterial biofilms in vitro and those present in ex vivo granulomas. Taken together, the present study reports a proof-of-concept showing that surface proteomics in vitro and ex vivo proteomics combined are a valuable strategy to identify surface-exposed proteins on the mycobacterial biofilm. Biofilm-surface-binding nanobodies could be eventually used as homing agents to deliver biofilm-targeting treatments to the sites of persistent biofilm infection.}, } @article {pmid37184412, year = {2023}, author = {Yang, X and Tran, F and Zhang, P}, title = {Comparative Genomic Analyses of Escherichia coli from a Meat Processing Environment in Relation to Their Biofilm Formation and Persistence.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0018323}, pmid = {37184412}, issn = {2165-0497}, support = {FOS.01.17//Beef Cattle Research Council (BCRC)/ ; }, mesh = {Animals ; Cattle ; Humans ; *Escherichia coli/genetics/metabolism ; Genome-Wide Association Study ; Retrospective Studies ; Biofilms ; *Escherichia coli Proteins/genetics/metabolism ; Cellulose/metabolism ; Genomics ; Iron ; }, abstract = {We investigated the phylogeny of biofilm forming (BF) and nonbiofilm forming (NBF) Escherichia coli (n = 114) from a beef processing environment as well as genetic elements in their BF and persistence via a comparative genomic analysis. Phylogroup B1 made up the largest proportion of both the BF (73.8%) and NBF (50.9%) groups. E. coli from all of the sources that were examined had mixed phylogroups, except for those that were recovered from equipment after cleaning, which were exclusively from phylogroup B1. Both the core genome and gene content trees showed a tree-wide spread of BF strains, with clusters, including both BF and NBF strains. Genome-wide association studies (GWAS) via Scoary or Pyseer did not find any genes or mutations that were overrepresented in the BF group. A retrospective analysis of phenotypes found a significant correlation (P < 0.05) between BF ability and curli production, cellulose synthesis, and/or mobility. However, the BF group also included strains that were negative for curli and cellulose and/or missing encoding genes for the two traits. All curli and cellulose encoding genes were present in most genomes, regardless of their BF status. The degree of motility was correlated with both curli and cellulose production, and 80 common genes were overrepresented in all three of the trait-positive groups. A PTS enzyme II, a subsidiary gluconate catabolism pathway, and an iron-dicitrate transport system were more abundant in the persisting E. coli group. These findings suggest gene function redundancy in E. coli for biofilm formation as well as additional substrate utilization and iron acquisition in its persistence. IMPORTANCE The persistence of potentially hazardous bacteria is a major challenge for meat processing environments, which are conducive for biofilm formation. Marker genes/phenotypes are commonly used to differentiate biofilm forming E. coli strains from their nonbiofilm forming counterparts. We took a comparative genomic analysis approach to analyze E. coli strains that were from the same environment but were differentiated by their biofilm forming ability. A diversification of the genes involved in the biofilm formation of E. coli was observed. Even though there is a correlation on the population level between biofilm formation and the expression of curli and cellulose, uncertainties exist on the individual strain level. Novel substrate utilization and iron acquisition could contribute to the persistence of E. coli. These findings not only advance our understanding of the ecology of E. coli with respect to its persistence but also show that a marker gene/phenotype driven approach for the biofilm control of E. coli may not be prudent.}, } @article {pmid37183189, year = {2023}, author = {Thaarup, IC and Lichtenberg, M and Nørgaard, KTH and Xu, Y and Lorenzen, J and Thomsen, TR and Bjarnsholt, T}, title = {A collagen-based layered chronic wound biofilm model for testing antimicrobial wound products.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {}, number = {}, pages = {}, doi = {10.1111/wrr.13087}, pmid = {37183189}, issn = {1524-475X}, support = {//Magle Chemoswed AB/ ; NNF19OC0054390//Novo Nordisk Fonden/ ; NNF19OC0056411//Novo Nordisk Fonden/ ; }, abstract = {A new in vitro chronic wound biofilm model was recently published, which provided a layered scaffold simulating mammalian tissue composition on which topical wound care products could be tested. In this paper, we updated the model even further to mimic the dynamic influx of nutrients from below as is the case in a chronic wound. The modified in vitro model was created using collagen instead of agar as the main matrix component and contained both Staphylococcus aureus and Pseudomonas aeruginosa. The model was cast in transwell inserts and then placed in wound simulating media, which allowed for an exchange of nutrients and waste products across a filter. Three potential wound care products and chlorhexidine digluconate 2% solution as a positive control were used to evaluate the model. The tested products were composed of hydrogels made from completely biodegradable starch microspheres carrying different active compounds. The compounds were applied topically and left for 2-4 days. Profiles of oxygen concentration and pH were measured to assess the effect of treatments on bacterial activity. Confocal microscope images were obtained of the models to visualise the existence of microcolonies. Results showed that the modified in vitro model maintained a stable number of the two bacterial species over 6 days. In untreated models, steep oxygen gradients developed and pH increased to >8.0. Hydrogels containing active compounds alleviated the high oxygen consumption and decreased pH drastically. Moreover, all three hydrogels reduced the colony forming units significantly and to a larger extent than the chlorhexidine control treatment. Overall, the modified model expressed several characteristics similar to in vivo chronic wounds.}, } @article {pmid37182783, year = {2023}, author = {Zhou, T and Xiang, Y and Liu, S and Shao, Z and Liu, Y and Ma, H and He, Q and Chai, H}, title = {Insights into simultaneous nitrogen and phosphorus removal in biofilm: The overlooked comammox Nitrospira and the positive role of glycogen-accumulating organisms.}, journal = {The Science of the total environment}, volume = {887}, number = {}, pages = {164130}, doi = {10.1016/j.scitotenv.2023.164130}, pmid = {37182783}, issn = {1879-1026}, mesh = {*Ammonia ; *Nitrogen ; Nitrites ; Nitrates ; Nitrification ; Phosphorus ; RNA, Ribosomal, 16S/genetics ; In Situ Hybridization, Fluorescence ; Oxidation-Reduction ; Bacteria ; Biofilms ; Bioreactors/microbiology ; }, abstract = {Simultaneous nitrogen and phosphorus removal (SNPR) biofilm system is an effective wastewater treatment process. However, the understanding on the mechanism of functional microorganisms driving SNPR is still limited, especially the role of complete ammonia oxidation (comammox) Nitrospira and glycogen-accumulating organisms (GAO). In this study, a sequencing batch biofilm reactor (SBBR) performing SNPR was operated for 249 d. Based on the 16S rRNA gene, comammox amoA amplicon sequencing, metagenomics and batch experiment, we found that comammox Nitrospira was the main ammonia-oxidizing microorganisms (AOM) and provided nitrite for anaerobic ammonia oxidation (anammox) bacteria (AnAOB). Besides, GAO was dominated by the bacteria of genus Defluviicoccus and played a primary role in reducing nitrate rather than nitrite. Fluorescent in situ hybridization (FISH) analysis confirmed that Nitrospira was enriched in the inner layer of the biofilm. Thus, we put forward a novel insight into the mechanism of SNPR biofilm system. Comammox Nitrospira was responsible for nitrite and nitrate production in the inner biofilm, and AnAOB consumed the produced nitrite during the anammox process. While GAO reduced nitrate to nitrite and polyphosphate-accumulating organisms (PAO) converted nitrite to dinitrogen via denitrifying phosphorus removal in the outer biofilm. These findings provide a new understanding in SNPR biofilm system.}, } @article {pmid37180695, year = {2023}, author = {Teimoorian, M and Mirzaie, M and Tashakkorian, H and Gholinia, H and Alaghemand, H and Pournajaf, A and Ghorbanipour, R}, title = {Effects of adding functionalized graphene oxide nanosheets on physical, mechanical, and anti-biofilm properties of acrylic resin: In vitro- experimental study.}, journal = {Dental research journal}, volume = {20}, number = {}, pages = {37}, pmid = {37180695}, issn = {1735-3327}, abstract = {BACKGROUND: Polymethyl methacrylate resin is widely used in orthodontic treatments. Graphene oxide (GO) has reactive functional groups on its surface that facilitate binding to various materials such as polymers, biomolecules, DNA, and proteins. This study aimed to investigate the impact of adding functionalized GO nanosheets on the physical, mechanical, cytotoxicity, and anti-biofilm properties of acrylic resin.

MATERIALS AND METHODS: In this experimental study, fifty samples (for each test) were divided into groups of 10, in the form of acrylic resin discs with concentrations of 0, 0.25, 0.5, 1, and 2 weight percentage (wt%) of functionalized GO nanosheets and also the control group. Samples were evaluated in terms of physical properties (surface hardness, surface roughness, compressive strength, fracture toughness, and flexural strength), anti-biofilm properties (On four groups of micro-organisms, including Streptococcus mutans, Streptococcus sanguis, Staphylococcus aureus, and Candida albicans), and cytotoxicity. Data were analyzed using SPSS software version 22, descriptive statistics, one-way analysis of variance test, and Tukey post hoc test. The significance level was considered P < 0.05.

RESULTS: No significant difference was observed between the different groups with weight percentages of 0.25, 0.5, 1, and 2% nano GO (nGO) and the control group (without nGO) in terms of surface roughness and toughness. However, compressive strength, three-point flexural strength, and surface hardness showed significant differences between the groups. Furthermore, the degree of cytotoxicity increased by increasing the weight percentage of nano-GO.

CONCLUSION: The addition of functionalized nGO in appropriate concentrations to polymethyl methacrylate can improve the anti-bacterial and anti-fungal biofilm properties without changing or increasing their physical and mechanical properties.}, } @article {pmid37180277, year = {2023}, author = {Wang, C and Xiong, Y and Bao, C and Wei, Y and Wen, Z and Cao, X and Yu, Z and Deng, X and Li, G and Deng, Q}, title = {Antibacterial and anti-biofilm activity of radezolid against Staphylococcus aureus clinical isolates from China.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1131178}, pmid = {37180277}, issn = {1664-302X}, abstract = {Although the potent antibacterial ability of radezolid against Staphylococcus aureus has been widely reported worldwide, its antibacterial and anti-biofilm activity against the S. aureus clinical isolates from China remains elusive. In this study, the minimum inhibitory concentration (MIC) of radezolid was determined in S. aureus clinical isolates from China using the agar dilution method, and the relationship between radezolid susceptibility and ST distribution was also investigated. The anti-biofilm activity of radezolid against S. aureus was determined by a crystal violet assay and compared with that of linezolid and contezolid. The quantitative proteomics of S. aureus treated with radezolid was analyzed, and the genetic mutations in radezolid-induced resistant S. aureus were determined by whole-genome sequencing. The dynamic changes in transcriptional expression levels of several biofilm-related genes were analyzed by quantitative RT-PCR. Our data showed that radezolid MIC ranged from ≤0.125 to 0.5 mg/L, which was almost 1/4 × MIC of linezolid against S. aureus, indicating the greater antibacterial activity of radezolid than linezolid. The S. aureus clinical isolates with radezolid MICs of 0.5 mg/L were most widely distributed in ST239 of MRSA and ST7 of MSSA. Moreover, the more robust anti-biofilm activity of radezolid with subinhibitory concentrations (1/8 × MIC and 1/16 × MIC) was demonstrated against S. aureus when compared with that of contezolid and linezolid. Genetic mutations were found in glmS, 23S rRNA, and DUF1542 domain-containing protein in radezolid-induced resistant S. aureus selected by in vitro induction of drug exposure. Quantitative proteomic analysis of S. aureus indicated that the global expression of some biofilm-related and virulence-related proteins was downregulated. Quantitative RT-PCR further confirmed that the expressions of some downregulated biofilm-related proteins, including sdrD, carA, sraP, hlgC, sasG, spa, sspP, fnbA, and oatA, were decreased after 12 h and 24 h of exposure to radezolid. Conclusively, radezolid shows robust antibacterial and anti-biofilm activity against S. aureus clinical isolates from China when compared with contezolid and linezolid.}, } @article {pmid37179329, year = {2023}, author = {Anderson, AC and von Ohle, C and Frese, C and Boutin, S and Bridson, C and Schoilew, K and Peikert, SA and Hellwig, E and Pelz, K and Wittmer, A and Wolff, D and Al-Ahmad, A}, title = {The oral microbiota is a reservoir for antimicrobial resistance: resistome and phenotypic resistance characteristics of oral biofilm in health, caries, and periodontitis.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {22}, number = {1}, pages = {37}, pmid = {37179329}, issn = {1476-0711}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; Drug Resistance, Bacterial/genetics ; Dental Caries Susceptibility ; *Microbiota/genetics ; *Periodontitis/genetics ; Bacteria ; Genes, Bacterial ; }, abstract = {BACKGROUND: Antimicrobial resistance (AMR) is an ever-growing threat to modern medicine and, according to the latest reports, it causes nearly twice as many deaths globally as AIDS or malaria. Elucidating reservoirs and dissemination routes of antimicrobial resistance genes (ARGs) are essential in fighting AMR. Human commensals represent an important reservoir, which is underexplored for the oral microbiota. Here, we set out to investigate the resistome and phenotypic resistance of oral biofilm microbiota from 179 orally healthy (H), caries active (C), and periodontally diseased (P) individuals (TRN: DRKS00013119, Registration date: 22.10.2022). The samples were analysed using shotgun metagenomic sequencing combined, for the first time, with culture technique. A selection of 997 isolates was tested for resistance to relevant antibiotics.

RESULTS: The shotgun metagenomics sequencing resulted in 2,069,295,923 reads classified into 4856 species-level OTUs. PERMANOVA analysis of beta-diversity revealed significant differences between the groups regarding their microbiota composition and their ARG profile. The samples were clustered into three ecotypes based on their microbial composition. The bacterial composition of H and C samples greatly overlapped and was based on ecotypes 1 and 2 whereas ecotype 3 was only detected in periodontitis. We found 64 ARGs conveying resistance to 36 antibiotics, particularly to tetracycline, macrolide-lincosamide-streptogramin, and beta-lactam antibiotics, and a correspondingly high prevalence of phenotypic resistance. Based on the microbiota composition, these ARGs cluster in different resistotypes, and a higher prevalence is found in healthy and caries active than in periodontally diseased individuals. There was a significant association between the resistotypes and the ecotypes. Although numerous associations were found between specific antibiotic resistance and bacterial taxa, only a few taxa showed matching associations with both genotypic and phenotypic analyses.

CONCLUSIONS: Our findings show the importance of the oral microbiota from different niches within the oral cavity as a reservoir for antibiotic resistance. Additionally, the present study showed the need for using more than one method to reveal antibiotic resistance within the total oral biofilm, as a clear mismatch between the shotgun metagenomics method and the phenotypic resistance characterization was shown.}, } @article {pmid37177837, year = {2023}, author = {Bae, WY and Jung, WH and Lee, YJ and Shin, SL and An, YK and Kim, TR and Sohn, M}, title = {Heat-treated Pediococcus acidilactici LM1013-mediated inhibition of biofilm formation by Cutibacterium acnes and its application in acne vulgaris: A single-arm clinical trial.}, journal = {Journal of cosmetic dermatology}, volume = {}, number = {}, pages = {}, doi = {10.1111/jocd.15809}, pmid = {37177837}, issn = {1473-2165}, support = {//Ministry of SMEs and Startups/ ; }, abstract = {PURPOSE: Acne vulgaris is a common skin disease accompanied by chronic inflammation in the pilosebaceous follicles, resulting from excessive Cutibacterium acnes. This study aimed to investigate the inhibition of biofilm formation by C. acnes ATCC 6919 using heat-treated Pediococcus acidilactici LM1013 (HT-LM1013), previously isolated from the Korean traditional fermented alcoholic beverage-makgeolli, and its application as a leave-on-type product for patients with acne vulgaris.

METHODS: HT-LM1013 was prepared by Lactomason and homogenized using a high-pressure homogenizer. The minimum inhibitory concentration (MIC), tricarboxylic acid (TCA) cycle, and lipase activity were evaluated for C. acnes inhibition. Inhibition of biofilm formation was demonstrated using a crystal violet solution. Damaged C. acnes was observed using field-emission scanning electron microscopy (FE-SEM). Clinical trials were performed using a leave-on-type product containing HT-LM1013.

RESULTS: HT-LM1013 inhibited the TCA cycle (36.80%) and lipase activity using palmitate (31.89%), stearate (36.91%), and oleate (30.86%) as substrates at 1 × MIC (p < 0.01). After treatment with HT-LM1013, concave and elongated shapes of C. acnes were observed by FE-SEM. In addition, HT-LM1013 inhibited biofilm formation by 71.75% at 1 × MIC (p < 0.001) and removed 73.35% of mature biofilms (p < 0.01). In the clinical trial, the leave-on-type product decreased the number of closed comedones from 14.04 to 10.22, open comedones from 7.22 to 4.39%, and sebum content to 76.23% at week 4 (p < 0.01). The satisfaction score of the participants was recorded 3.83 on a five-point scale.

CONCLUSION: HT-LM1013 is potent for the treatment of acne vulgaris.}, } @article {pmid37177285, year = {2023}, author = {Vulović, S and Nikolić-Jakoba, N and Radunović, M and Petrović, S and Popovac, A and Todorović, M and Milić-Lemić, A}, title = {Biofilm Formation on the Surfaces of CAD/CAM Dental Polymers.}, journal = {Polymers}, volume = {15}, number = {9}, pages = {}, pmid = {37177285}, issn = {2073-4360}, abstract = {Dental polymers are now available as monolithic materials which can be readily used in computer-aided design and computer-aided manufacturing (CAD/CAM) systems. Despite possessing numerous advantages over conventionally produced polymers, the polymers produced by either of these systems fail to exhibit immunity to surface microbial adhesion when introduced into the oral environment, leading to the development of oral diseases. The aim of this study was to analyze the biofilm formation of six microorganisms from the oral cavity and its correlation to the surface characteristics of CAD/CAM dental polymers. A total of ninety specimens were divided into three groups: resin-based composite, polymethyl methacrylate, and polyether ether ketone. The experimental procedure included surface roughness and water contact angle measurements, colony forming unit counting, and scanning electron microscopy analysis of biofilm formed on the surface of the tested materials. The data were analyzed using the Kruskal-Wallis test, with a Dunn's post hoc analysis, and one way analysis of variance, with a Tukey's post hoc test; the correlation between the measurements was tested using Spearman's correlation coefficient, and descriptive statistics were used to present the data. Despite using the same manufacturing procedure, as well as the identical manufacturer's finishing and polishing protocols, CAD/CAM dental polymers revealed significant differences in surface roughness and water contact angle, and the increased values of both parameters led to an increase in biofilm formation on the surface of the materials. The CAD/CAM resin-based composite showed the lowest number of adhered microorganisms compared to CAD/CAM polymethyl methacrylate and CAD/CAM polyether ether ketone.}, } @article {pmid37175289, year = {2023}, author = {Ye, X and Mao, S and Li, Y and Yang, Z and Du, A and Wang, H}, title = {Design, Synthesis, and Biological Evaluation of Phenyloxadiazole Sulfoxide Derivatives as Potent Pseudomonas aeruginosa Biofilm Inhibitors.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {9}, pages = {}, pmid = {37175289}, issn = {1420-3049}, support = {42276137, 22101255, and 82204202//National Natural Science Foundation of China/ ; 2021C03084//Key Research and Development Program of Zhejiang/ ; 2020414801729//Zhejiang University of Technology/ ; }, mesh = {*Pseudomonas aeruginosa ; Molecular Docking Simulation ; *Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; Quorum Sensing ; Virulence Factors/genetics ; Bacterial Proteins/metabolism ; }, abstract = {With the development of antimicrobial agents, researchers have developed new strategies through key regulatory systems to block the expression of virulence genes without affecting bacterial growth. This strategy can minimize the selective pressure that leads to the emergence of resistance. Quorum sensing (QS) is an intercellular communication system that plays a key role in the regulation of bacterial virulence and biofilm formation. Studies have revealed that the QS system controls 4-6% of the total number of P. aeruginosa genes, and quorum sensing inhibitors (QSIs) could be a promising target for developing new prevention and treatment strategies against P. aeruginosa infection. In this study, four series of phenyloxadiazole and phenyltetrazole sulfoxide derivatives were synthesized and evaluated for their inhibitory effects on P. aeruginosa PAO1 biofilm formation. Our results showed that 5b had biofilm inhibitory activity and reduced the production of QS-regulated virulence factors in P. aeruginosa. In addition, silico molecular docking studies have shown that 5b binds to the P. aeruginosa QS receptor protein LasR through hydrogen bond interaction. Preliminary structure-activity relationship and docking studies show that 5b has broad application prospects as an anti-biofilm compound, and further research will be carried out in the future to solve the problem of microbial resistance.}, } @article {pmid37174548, year = {2023}, author = {Gao, M and Zuo, J and Shen, Y and Yuan, S and Gao, S and Wang, Y and Wang, Y and Yi, L}, title = {Modeling Co-Infection by Streptococcus suis and Haemophilus parasuis Reveals Influences on Biofilm Formation and Host Response.}, journal = {Animals : an open access journal from MDPI}, volume = {13}, number = {9}, pages = {}, pmid = {37174548}, issn = {2076-2615}, abstract = {Streptococcus suis (S. suis) and Haemophilus parasuis (H. parasuis) are two primary pathogens currently affecting the porcine industry. They often cause encephalitis and arthritis. They also frequently co-infect in clinical settings. In the current study, we identified significant correlations between S. suis and H. parasuis. The results from CI versus RIR suggested that S. suis and H. parasuis were competitive in general. Compared to mono-species biofilm, the biomass, bio-volume, and thickness of mixed-species biofilms were significantly higher, which was confirmed using crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. Compared to mono-species biofilm, the viable bacteria in the mixed-species biofilms were significantly lower, which was confirmed using the enumeration of colony-forming units (CFU cm[-2]). The susceptibility of antibiotics in the co-culture decreased in the planktonic state. In contrast, biofilm state bacteria are significantly more difficult to eradicate with antibiotics than in a planktonic state. Whether in planktonic or biofilm state, the expression of virulence genes of S. suis and H. parasuis in mixed culture was very different from that in single culture. Subsequently, by establishing a mixed infection model in mice, we found that the colonization of the two pathogens in organs increased after mixed infection, and altered the host's inflammatory response. In summary, our results indicate that S. suis and H. parasuis compete when co-cultured in vitro. Surprisingly, S. suis and H. parasuis synergistically increased colonization capacity after co-infection in vivo. This study elucidated the interaction between S. suis and H. parasuis during single infections and co-infections. Future studies on bacterial disease control and antibiotic treatment should consider the interaction of mixed species.}, } @article {pmid37174455, year = {2023}, author = {Thames, HT and Pokhrel, D and Willis, E and Rivers, O and Dinh, TTN and Zhang, L and Schilling, MW and Ramachandran, R and White, S and Sukumaran, AT}, title = {Salmonella Biofilm Formation under Fluidic Shear Stress on Different Surface Materials.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {9}, pages = {}, pmid = {37174455}, issn = {2304-8158}, support = {6066-31000-015-00D//Agricultural Research Service/ ; MIS-322380//National Institute of Food and Agriculture/ ; }, abstract = {This study characterized biofilm formation of various Salmonella strains on common processing plant surface materials (stainless steel, concrete, rubber, polyethylene) under static and fluidic shear stress conditions. Surface-coupons were immersed in well-plates containing 1 mL of Salmonella (6 log CFU/mL) and incubated aerobically for 48 h at 37 °C in static or shear stress conditions. Biofilm density was determined using crystal violet assay, and biofilm cells were enumerated by plating on tryptic soy agar plates. Biofilms were visualized using scanning electron microscopy. Data were analyzed by SAS 9.4 at a significance level of 0.05. A surface-incubation condition interaction was observed for biofilm density (p < 0.001). On stainless steel, the OD600 was higher under shear stress than static incubation; whereas, on polyethylene, the OD600 was higher under static condition. Enumeration revealed surface-incubation condition (p = 0.024) and surface-strain (p < 0.001) interactions. Among all surface-incubation condition combinations, the biofilm cells were highest on polyethylene under fluidic shear stress (6.4 log/coupon; p < 0.001). Biofilms of S. Kentucky on polyethylene had the highest number of cells (7.80 log/coupon) compared to all other strain-surface combinations (p < 0.001). Electron microscopy revealed morphological and extracellular matrix differences between surfaces. Results indicate that Salmonella biofilm formation is influenced by serotype, surface, and fluidic shear stress.}, } @article {pmid37172659, year = {2023}, author = {Kang, CE and Park, YJ and Kim, JH and Lee, NK and Paik, HD}, title = {Probiotic Weissella cibaria displays antibacterial and anti-biofilm effect against cavity-causing Streptococcus mutans.}, journal = {Microbial pathogenesis}, volume = {180}, number = {}, pages = {106151}, doi = {10.1016/j.micpath.2023.106151}, pmid = {37172659}, issn = {1096-1208}, mesh = {Humans ; Streptococcus mutans ; *Dental Caries/prevention & control ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Probiotics/pharmacology ; }, abstract = {Streptococcus mutans is a significant contributor to dental caries and causes functional and aesthetic discomfort. Weissella cibaria strains were isolated from kimchi, and their functional properties were determined. In this study, the antibacterial and antibiofilm effects of four W. cibaria strains (D29, D30, D31, and B22) were evaluated against three S. mutans strains using culture fluid and cell-free supernatants. The results showed that W. cibaria reduced the exopolysaccharides production and auto-aggregation, increased co-aggregation, and downregulated virulence factors, leading to the inhibition of bacterial growth and biofilm formation. These findings were confirmed using scanning electron microscopy and confocal laser scanning microscopy. These results indicate that oral health can be potentially improved by W. cibaria.}, } @article {pmid37172383, year = {2023}, author = {Liu, YJ and Li, ZH and He, YT and Yuan, L and Sheng, GP}, title = {Antibiotic resistomes in face-mask biofilm along an urban river: Multiple drivers and co-occurrence with human opportunistic pathogens.}, journal = {Journal of hazardous materials}, volume = {455}, number = {}, pages = {131587}, pmid = {37172383}, issn = {1873-3336}, mesh = {Humans ; *Genes, Bacterial ; Masks ; Rivers ; Anti-Bacterial Agents/pharmacology/analysis ; Pandemics ; *COVID-19 ; Water ; Biofilms ; }, abstract = {Discarded face masks from the global COVID-19 pandemic have contributed significantly to plastic pollution in surface water, whereas their potential as a reservoir for aquatic pollutants is not well understood. Herein, we conducted a field experiment along a human-impacted urban river, investigating the variations of antibiotic resistance genes (ARGs), pathogens, and water-borne contaminants in commonly-used face masks. Results showed that high-biomass biofilms formed on face masks selectively enriched more ARGs than stone biofilm (0.08-0.22 vs 0.07-0.15 copies/16 S rRNA gene copies) from bulk water, which mainly due to unique microbial communities, enhanced horizontal gene transfer, and selective pressure of accumulated contaminants based on redundancy analysis and variation partitioning analysis. Several human opportunistic pathogens (e.g., Acinetobacter, Escherichia-Shigella, Bacillus, and Klebsiella), which are considered potential ARG carriers, were also greatly concentrated in face-mask biofilms, imposing a potential threat to aquatic ecological environment and human health. Moreover, wastewater treatment plant effluents, as an important source of pollutants to urban rivers, further aggravated the abundances of ARGs and opportunistic pathogens in face-mask biofilms. Our findings demonstrated that discarded face masks provide a hotspot for the proliferation and spread of ARGs and pathogens in urban water, highlighting the urgent requirement for implementing stricter regulations in face mask disposal.}, } @article {pmid37171757, year = {2023}, author = {Roy, B and Maitra, D and Biswas, A and Chowdhury, N and Ganguly, S and Bera, M and Dutta, S and Golder, S and Roy, S and Ghosh, J and Mitra, AK}, title = {Efficacy of High-Altitude Biofilm-Forming Novel Bacillus subtilis Species as Plant Growth-Promoting Rhizobacteria on Zea mays L.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37171757}, issn = {1559-0291}, support = {102/IFD/SAN/3183/2021-2022//Department of Biotechnology, Ministry of Science and Technology, India/ ; }, abstract = {With the global population explosion, the need for increasing crop productivity is reaching its peak. The significance of organic means of cultivation including biofertilizers and biopesticides is undeniable in this context. Over the last few decades, the use of rhizobacteria to induce crop productivity has gained particular interest of researchers. Of these, several Bacillus spp. have been known for their potential plant growth-promoting and phyto-pathogenic actions. Keeping this background in mind, this study was formulated with an aim to unravel the PGPR and phyto-pathogenic potency of Bacillus sp. isolated from extreme environmental conditions, viz. high-altitude waters of Ganges at Gangotri (Basin Extent Longitude Latitude-73° 2' to 89° 5' E 21° 6' to 31° 21' N). Based on recent studies showing the impact of biofilm on bacterial PGPR potency, three novel strains of Bacillus subtilis were isolated on basis of their extremely high biofilm-producing abilities (BRAM_G1: Accession Number MW006633; BRAM_G2: Accession Numbers MT998278-MT998280; BRAM_G3: Accession Number MT998617), and were tested for their PGPR properties like nutrient sequestration, growth hormone production (IAA, GA3), stress-responsive enzyme production (ACC deaminase) and lignocellulolytic and agriculturally important enzyme productions. The strains were further tested for the plethora of metabolites (liquid and VOCs) exuded by them. Finally, the strains both in individually and in an association, i.e. consortium was tested on a test crop, viz. Zea mays L., and the data were collected at regular intervals and the results were statistically analysed. In the present study, the role of high-altitude novel Bacillus subtilis strains as potent PGPR has been analysed statistically.}, } @article {pmid37170818, year = {2023}, author = {Snowdon, AA and Dennington, SP and Longyear, JE and Wharton, JA and Stoodley, P}, title = {Surface properties influence marine biofilm rheology, with implications for ship drag.}, journal = {Soft matter}, volume = {19}, number = {20}, pages = {3675-3687}, doi = {10.1039/d2sm01647h}, pmid = {37170818}, issn = {1744-6848}, mesh = {*Ships ; *Biofilms ; Surface Properties ; Rheology ; Friction ; }, abstract = {Marine biofilms on ship hulls increase frictional drag, which has economic and environmental consequences. It is hypothesised that biofilm mechanics, such as viscoelasticity, play a critical role in biofilm-associated drag, yet is a poorly studied area. The current study aimed to rheologically characterise ship-relevant marine biofilms. To combat marine biofilms on ship hulls, fouling-control coatings are often applied; therefore, the effect of different surfaces on marine biofilm mechanics was also investigated. Three surfaces were tested: a non-biocidal, chemically inert foul-release coating (FRC), an inert primer (ACP) and inert PVC. Physical properties of biofilms were explored using Optical Coherence Tomography (OCT) and a parallel-plate rheometer was used for rheological testing. Image analysis revealed differences in the thickness, roughness, and percent coverage between the different biofilms. Rheological testing showed that marine biofilms, grown on FRC and ACP acted as viscoelastic materials, although there were differences. FRC biofilms had a lower shear modulus, a higher viscosity, and a higher yield stress than the ACP biofilms, suggesting that the FRC biofilms were more readily deformable but potentially more robust. The results confirmed that surface treatment influences the structural and mechanical properties of ship-relevant marine biofilms, which could have implications for drag. A better understanding of how different surface treatments affect marine biofilm rheology is required to improve our knowledge on biofilm fluid-structure interactions and to better inform the coating industry of strategies to control biofilm formation and reduce drag.}, } @article {pmid37170476, year = {2023}, author = {Delaney, C and Alapati, S and Alshehri, M and Kubalova, D and Veena, CLR and Abusrewil, S and Short, B and Bradshaw, D and Brown, JL}, title = {Investigating the role of Candida albicans as a universal substrate for oral bacteria using a transcriptomic approach: implications for interkingdom biofilm control?.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {}, number = {}, pages = {}, doi = {10.1111/apm.13327}, pmid = {37170476}, issn = {1600-0463}, abstract = {Candida albicans is frequently identified as a colonizer of the oral cavity in health and has recently been termed a "keystone" commensal due to its role on the bacterial communities. However, the role that C. albicans plays in such interactions is not fully understood. Therefore, this study aimed to identify the relationship between C. albicans and bacteria associated with oral symbiosis and dysbiosis. To do this, we evaluated the ability of C. albicans to support the growth of the aerobic commensal Streptococcus gordonii and the anaerobic pathogens Fusobacterium nucleatum and Porphyromonas gingivalis in the biofilm environment. RNA-Sequencing with the Illumina platform was then utilized to identify C. albicans gene expression and functional pathways involved during such interactions in dual-species and a 4-species biofilm model. Results indicated that C. albicans was capable of supporting growth of all three bacteria, with a significant increase in colony counts of each bacteria in the dual-species biofilm (p < 0.05). We identified specific functional enrichment of pathways in our 4-species community as well as transcriptional profiles unique to the F. nucleatum and S. gordonii dual-species biofilms, indicating a species-specific effect on C. albicans. Candida-related hemin acquisition and heat shock protein mediated processes were unique to the organism following co-culture with anaerobic and aerobic bacteria, respectively, suggestive that such pathways may be feasible options for therapeutic targeting to interfere with these fungal-bacterial interactions. Targeted antifungal therapy may be considered as an option for biofilm destabilization and treatment of complex communities. Moving forward, we propose that further studies must continue to investigate the role of this fungal organism in the context of the interkingdom nature of oral diseases.}, } @article {pmid37169797, year = {2023}, author = {Auria, E and Hunault, L and England, P and Monot, M and Pipoli Da Fonseca, J and Matondo, M and Duchateau, M and Tremblay, YDN and Dupuy, B}, title = {The cell wall lipoprotein CD1687 acts as a DNA binding protein during deoxycholate-induced biofilm formation in Clostridioides difficile.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {24}, pmid = {37169797}, issn = {2055-5008}, mesh = {*Clostridioides difficile/genetics ; Clostridioides ; DNA-Binding Proteins/metabolism ; Biofilms ; Lipoproteins/genetics/metabolism ; Deoxycholic Acid/pharmacology/metabolism ; }, abstract = {The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesized that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is still poorly understood. It has been shown that specific molecules such as deoxycholate (DCA) or metronidazole induce biofilm formation, but the mechanisms involved remain elusive. In this study, we describe the role of the C. difficile lipoprotein CD1687 during DCA-induced biofilm formation. We showed that the expression of CD1687, which is part of an operon within the CD1685-CD1689 gene cluster, is controlled by multiple transcription starting sites and some are induced in response to DCA. Only CD1687 is required for biofilm formation and the overexpression of CD1687 is sufficient to induce biofilm formation. Using RNAseq analysis, we showed that CD1687 affects the expression of transporters and metabolic pathways and we identified several potential binding partners by pull-down assay, including transport-associated extracellular proteins. We then demonstrated that CD1687 is surface exposed in C. difficile, and that this localization is required for DCA-induced biofilm formation. Given this localization and the fact that C. difficile forms eDNA-rich biofilms, we confirmed that CD1687 binds DNA in a non-specific manner. We thus hypothesize that CD1687 is a component of the downstream response to DCA leading to biofilm formation by promoting interaction between the cells and the biofilm matrix by binding eDNA.}, } @article {pmid37168114, year = {2023}, author = {Németh, A and Ainsworth, J and Ravishankar, H and Lens, PNL and Heffernan, B}, title = {Temperature dependence of nitrification in a membrane-aerated biofilm reactor.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1114647}, pmid = {37168114}, issn = {1664-302X}, abstract = {The membrane-aerated biofilm reactor (MABR) is a novel method for the biological treatment of wastewaters and has been successfully applied for nitrification. To improve the design and adaptation of MABR processes for colder climates and varying temperatures, the temperature dependence of a counter-diffusional biofilm's nitrification performance was investigated. A lab-scale MABR system with silicone hollow fibre membranes was operated at various temperatures between 8 and 30°C, and batch tests were performed to determine the ammonia oxidation kinetics. Biofilm samples were taken at 8 and 24°C and analysed with 16S rRNA sequencing to monitor changes in the microbial community composition, and a mathematical model was used to study the temperature dependence of mass transfer. A high nitrification rate (3.08 g N m[-2] d[-1]) was achieved at 8°C, and temperature dependence was found to be low (θ = 1.024-1.026) compared to suspended growth processes. Changes in the community composition were moderate, Nitrospira defluvii remaining the most dominant species. Mass transfer limitations were shown to be largely responsible for the observed trends, consistent with other biofilm processes. The results show that the MABR is a promising technology for low temperature nitrification, and appropriate management of the mass transfer resistance can optimise the process for both low and high temperature operation.}, } @article {pmid37166296, year = {2023}, author = {Shen, L and Zhang, J and Chen, Y and Rao, L and Wang, X and Zhao, H and Wang, B and Xiao, Y and Yu, J and Xu, Y and Shi, J and Han, W and Song, Z and Yu, F}, title = {Small-Molecule Compound CY-158-11 Inhibits Staphylococcus aureus Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0004523}, pmid = {37166296}, issn = {2165-0497}, support = {82102458//Foundation of the Awareness of Nature/ ; }, mesh = {Humans ; *Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Staphylococcal Infections/drug therapy ; Gentian Violet/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus aureus is an important human pathogen and brings about many community-acquired, hospital-acquired, and biofilm-associated infections worldwide. It tends to form biofilms, triggering the release of toxins and initiating resistance mechanisms. As a result of the development of S. aureus tolerance to antibiotics, there are few drugs can availably control biofilm-associated infections. In this study, we synthesized a novel small-molecule compound CY-158-11 (C22H14Cl2NO2Se2) and proved its inhibitory effect on the biofilm formation of S. aureus at a subinhibitory concentration (1/8 MIC). The subinhibitory concentration of CY-158-11 not only did not affect the growth of bacteria but also had no toxicity to A549 cells or G. mellonella. Total biofilm biomass was investigated by crystal violet staining, and the results were confirmed by SYTO 9 and PI staining through confocal laser scanning microscopy. Moreover, CY-158-11 effectively prevented initial attachment and repressed the production of PIA instead of autolysis. RT-qPCR analysis also exhibited significant suppression of the genes involved in biofilm formation. Taken together, CY-158-11 exerted its inhibitory effects against the biofilm formation in S. aureus by inhibiting cell adhesion and the expression of icaA related to PIA production. IMPORTANCE Most bacteria exist in the form of biofilms, often strongly adherent to various surfaces, causing bacterial resistance and chronic infections. In general, antibacterial drugs are not effective against biofilms. The small-molecule compound CY-158-11 inhibited the biofilm formation of S. aureus at a subinhibitory concentration. By hindering adhesion and PIA-mediated biofilm formation, CY-158-11 exhibits antibiofilm activity toward S. aureus. These findings point to a novel therapeutic agent for combating intractable S. aureus-biofilm-related infections.}, } @article {pmid37165699, year = {2023}, author = {Russo, A and Gatti, A and Felici, S and Gambardella, A and Fini, M and Neri, MP and Zaffagnini, S and Lazzarotto, T}, title = {Piezoelectric ultrasonic debridement as new tool for biofilm removal from orthopedic implants: A study in vitro.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {}, number = {}, pages = {}, doi = {10.1002/jor.25599}, pmid = {37165699}, issn = {1554-527X}, support = {//Mectron S.p.A. (Carasco, Italy)/ ; }, abstract = {Pulse lavage (PL) debridement is the standard treatment used in Debridement, Antibiotics and Implant Retention (DAIR) for bacterial biofilm removal during acute and early postoperative cases of periprosthetic joint infection (PJI). The failure rate of DAIR is still high due to the inadequacy of PL in removing the biofilm. Ultrasound-based techniques are a well-established tool for PJI diagnosis due to their ability to completely eradicate the biofilm from implant surfaces. Hence, this study investigates the efficiency of a piezoelectric ultrasonic scalpel (PUS) in removing bacterial biofilm from different orthopedic implant materials in vitro and compares the results with PL. Biofilms of methicillin-resistant Staphylococcus aureus strains were grown on titanium alloy (Ti6Al4V ELI), stainless steel (AISI 316L), and ultrahigh molecular weight polyethylene (UHMWPE) disks for 24 h. The disks of each material were divided into three groups: (i) a control group (no lavage/debridement), (ii) a group treated with PL, (iii) a group treated with PUS. The disks were then sonicated for viable cell count to measure the residual biofilm content. Compared to the initial cell count (10[5] CFU/mL for each material), PL showed a two-log reduction of CFU/mL (p < 0.001 for each material), while for PUS a four-log reduction was found (p < 0.001 for each material). The comparison between the two lavage/debridement displayed a two-log reduction of CFU/mL (p < 0.001 for each material) of PUS compared with PL. Its increased efficiency compared with PL promotes the use of PUS in removing bacterial biofilm from orthopedic implants, suggesting its implementation to improve the success rate of DAIR.}, } @article {pmid37165063, year = {2023}, author = {Kato, H and Okino, N and Kijitori, H and Izawa, Y and Wada, Y and Maki, M and Yamamoto, T and Yano, T}, title = {Analysis of biofilm and bacterial communities in the towel environment with daily use.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {7611}, pmid = {37165063}, issn = {2045-2322}, mesh = {Humans ; Bacteria ; *Microbiota ; *Alphaproteobacteria ; Biofilms ; }, abstract = {Towels differ remarkably from other textile products in their fibre structure and usage, and microbial behaviours on towels remain underexplored. Thus, we evaluated biofilm formation on towels during use for 6 months in daily life and analysed its relationship with odour, dullness, and laundry habits. The towels exhibited odour and dullness after 2 months of use and biofilm structures were observed over the 6 months, especially in the ground warp part. Polysaccharides, proteins, nucleic acids, and viable counts on the towels increased over time. The microbiota was significantly different from that on human skin and clothing. Several species of Alphaproteobacteria were correlated with dullness intensity and the quantity of biofilm components. Therefore, bacterial species that specifically adapt to the towel fibre environment could form biofilms. Our results demonstrate bacterial diversity in textile products and suggest careful consideration of the textile fibre material, structure, and usage pattern to control bacterial communities.}, } @article {pmid37163833, year = {2023}, author = {Ni, M and Zhao, Y and Pan, Y and Li, D and Huang, Y and Chen, Z and Li, L and Song, Z}, title = {A new insight in enhancing phosphate enrichment in biofilm process: Comparison of the key metabolic pathways in highly-efficient and dominant PAOs based on metagenomics.}, journal = {Journal of environmental management}, volume = {341}, number = {}, pages = {118114}, doi = {10.1016/j.jenvman.2023.118114}, pmid = {37163833}, issn = {1095-8630}, mesh = {*Phosphates ; *Extracellular Polymeric Substance Matrix ; Biofilms ; Acyl-Butyrolactones ; Carbon ; Metabolic Networks and Pathways ; Bioreactors ; Sewage ; }, abstract = {The formation of dominant phosphate-accumulating organisms (PAOs) is essential for the high enrichment of phosphate in biofilm sequencing batch reactors (BSBR) for phosphorus recovery. The dominant PAOs in the biofilm process have not been isolated and purified, and the key metabolic pathways that promote the formation of dominant PAOs are still unclear. In this study, four strains of highly-efficient PAOs were obtained by an innovative isolation procedure. The relationship between the abundance of highly-efficient and dominant PAOs and the phosphate removal ability was compared. We found that the abundance of PAOs was positively correlated with the phosphate removal efficiency in vitro pure culture and complex biofilm process. Metagenomics analysis revealed that compared with highly-efficient PAOs cultured in vitro, dominant PAOs in biofilms had unique key metabolic pathways, F-ATPases and N-Acyl homoserine lactones (AHLs). F-ATPases are important for maintaining the proton motive force (PMF) required for the uptake of carbon sources by PAOs, and AHLs are participating in phosphate metabolism through quorum sensing (QS) mediated secretion of extracellular polymeric substance (EPS). The formation of dominant PAOs was promoted by optimizing carbon source uptake and phosphate metabolism. This study revealed that the difficult isolation of dominant PAOs was due to the AHLs-mediated QS, and we identified the key pathways regulating the formation of dominant PAOs in biofilms through genomics analysis. Our findings provide insights in enhancing phosphate enrichment in BSBR by modulating the components of microbial community under the low concentration of carbon source consumption.}, } @article {pmid37162737, year = {2023}, author = {Byeon, CH and Wang, PC and Byeon, IL and Akbey, Ü}, title = {Solution-state NMR assignment and secondary structure propensity of the full length and minimalistic-truncated prefibrillar monomeric form of biofilm forming functional amyloid FapC from Pseudomonas aeruginosa.}, journal = {Biomolecular NMR assignments}, volume = {}, number = {}, pages = {}, pmid = {37162737}, issn = {1874-270X}, abstract = {Functional bacterial amyloids provide structural scaffolding to bacterial biofilms. In contrast to the pathological amyloids, they have a role in vivo and are tightly regulated. Their presence is essential to the integrity of the bacterial communities surviving in biofilms and may cause serious health complications. Targeting amyloids in biofilms could be a novel approach to prevent chronic infections. However, structural information is very scarce on them in both soluble monomeric and insoluble fibrillar forms, hindering our molecular understanding and strategies to fight biofilm related diseases. Here, we present solution-state NMR assignment of 250 amino acid long biofilm-forming functional-amyloid FapC from Pseudomonas aeruginosa. We studied full-length (FL) and shorter minimalistic-truncated (L2R3C) FapC constructs without the signal-sequence that is required for secretion. 91% and 100% backbone NH resonance assignments for FL and L2R3C constructs, respectively, indicate that soluble monomeric FapC is predominantly disordered, with sizeable secondary structural propensities mostly as PP2 helices, but also as α-helices and β-sheets highlighting hotspots for fibrillation initiation interface. A shorter construct showing almost identical NMR chemical shifts highlights the promise of utilizing it for more demanding solid-state NMR studies that require methods to alleviate signal redundancy due to almost identical repeat units. This study provides key NMR resonance assignments for future structural studies of soluble, pre-fibrillar and fibrillar forms of FapC.}, } @article {pmid37161489, year = {2023}, author = {Cheng, C and Jiang, T and Zhang, D and Wang, H and Fang, T and Li, C}, title = {Attachment characteristics and kinetics of biofilm formation by Staphylococcus aureus on ready-to-eat cooked beef contact surfaces.}, journal = {Journal of food science}, volume = {88}, number = {6}, pages = {2595-2610}, doi = {10.1111/1750-3841.16592}, pmid = {37161489}, issn = {1750-3841}, support = {2021J01112//Nature and Science Foundation of Fujian Province/ ; CXZX2020119A//Special Foundation for Science and Technology Innovation of Fujian Agriculture and Forestry University/ ; Kxjq21012//Outstanding Young Talents Foundation of Fujian Agriculture and Forestry University/ ; 202210389381//Innovation and Entrepreneurship Project of Fujian Agriculture and Forestry University/ ; }, mesh = {Animals ; Cattle ; *Staphylococcus aureus ; *Food Handling/methods ; Kinetics ; Stainless Steel ; Biofilms ; Food Microbiology ; }, abstract = {Staphylococcus aureus is a food-borne pathogen that quickly forms biofilm on meat contact surfaces and thus poses a serious threat to the safety of the meat industry. This study evaluated the attachment, survival, and growth of S. aureus biofilm with exposure to environmental factors in the meat industry by simulated ready-to-eat (RTE) cooked beef product contamination scenarios. The results indicated that the meat-borne S. aureus biofilm formation dynamic could be divided into four different phases: initial adhesion (4-12 h), exponential (12-24 h), slow growth (1-3 days), and stationary (3-7 days). Meat-borne S. aureus has strong adhesion and biofilm formation ability, and its biofilm exhibits persistence, high-intensity metabolic activity, aerotaxis, and strain heterogeneity. This study has also demonstrated that in the long-term existence of meat-borne S. aureus biofilm on stainless steel and plexiglass surfaces (>7 days, 7.2-8.8 log CFU/cm[2]), expose to RTE cooked beef products, may cause it to become high-risk contaminated food. Meat-borne S. aureus that forms a dense and rough concave-convex in the shape of biofilm architecture was observed by scanning electron microscopy, consisting of complex components and adhesion of living and dead cells. This was further confirmed by the meat-borne S. aureus biofilm on the stainless steel surface by attenuated total reflectance Fourier transformed infrared spectroscopy, and the dominant peaks in biofilm spectra were mainly associated with proteins, polysaccharides, amino acid residues, and phospholipids (>50%). These findings may help in the identification of the main sources of contamination within the meat industry and the subsequent establishment of strategies for biofilm prevention and removal. PRACTICAL APPLICATION: This study revealed the meat-borne S. aureus biofilm formation mechanism and found that it exhibited strong colonization and biofilm-forming ability, which can persist on the contact surfaces of ready-to-eat beef products. These initial findings could provide information on the behavior of meat-borne S. aureus biofilm attached to meat contact surfaces under conditions commonly encountered in meat environments, which help to support the determination of the main sources of contamination within the meat industry and the subsequent establishment of strategies for biofilm prevention and removal. It was also helpful in controlling biofilm contamination and improving meat safety to minimize it.}, } @article {pmid37159227, year = {2023}, author = {Xu, D and Liu, J and Dai, H and Zhang, J and Hou, W and Wu, X and Zhao, Y}, title = {A premixed magnesium phosphate-based sealer with anti-biofilm ability for root canal filling.}, journal = {Journal of materials chemistry. B}, volume = {11}, number = {20}, pages = {4485-4497}, doi = {10.1039/d3tb00375b}, pmid = {37159227}, issn = {2050-7518}, mesh = {*Root Canal Filling Materials/pharmacology ; Magnesium Oxide ; Dental Pulp Cavity ; Phosphates/chemistry ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {The complex structure of the root canal system and microbial resistance increase the difficulty of endodontic treatment and the development of root canal sealers with good antibacterial and physicochemical properties is the key to treat refractory root canal infection. In the present study, a novel premixed root canal sealer containing trimagnesium phosphate (TMP), potassium dihydrogen phosphate (KH2PO4), magnesium oxide (MgO), zirconium oxide (ZrO2), and a bioactive oil phase was developed, and the physicochemical properties, radiopacity, antibacterial activity in vitro, anti-biofilm ability and cytotoxicity were investigated. MgO significantly improved the anti-biofilm ability and ZrO2 enhanced the radiopacity of the premixed sealer, and they had an obvious adverse effect on other properties. In addition, this sealer has advantages such as easy-to-use design, storabality, good sealing ability and biocompatibility. Therefore, this sealer has high potential for use in treating root canal infection.}, } @article {pmid37158596, year = {2023}, author = {Gomez, S and Bureau, L and John, K and Chêne, EN and Débarre, D and Lecuyer, S}, title = {Substrate stiffness impacts early biofilm formation by modulating Pseudomonas aeruginosa twitching motility.}, journal = {eLife}, volume = {12}, number = {}, pages = {}, pmid = {37158596}, issn = {2050-084X}, support = {ANR-19-CE42-0010//Agence Nationale de la Recherche/ ; ANR-11-LABX-0030//Labex Tec21/ ; }, mesh = {*Pseudomonas aeruginosa/genetics ; *Biofilms ; Fimbriae, Bacterial/metabolism ; Bacteria ; Cell Movement ; }, abstract = {Surface-associated lifestyles dominate in the bacterial world. Large multicellular assemblies, called biofilms, are essential to the survival of bacteria in harsh environments and are closely linked to antibiotic resistance in pathogenic strains. Biofilms stem from the surface colonization of a wide variety of substrates encountered by bacteria, from living tissues to inert materials. Here, we demonstrate experimentally that the promiscuous opportunistic pathogen Pseudomonas aeruginosa explores substrates differently based on their rigidity, leading to striking variations in biofilm structure, exopolysaccharides (EPS) distribution, strain mixing during co-colonization and phenotypic expression. Using simple kinetic models, we show that these phenotypes arise through a mechanical interaction between the elasticity of the substrate and the type IV pilus (T4P) machinery, that mediates the surface-based motility called twitching. Together, our findings reveal a new role for substrate softness in the spatial organization of bacteria in complex microenvironments, with far-reaching consequences on efficient biofilm formation.}, } @article {pmid37156358, year = {2023}, author = {O'Brien, EP and Mondal, K and Chen, CC and Hanley, L and Drummond, JL and Rockne, KJ}, title = {Relationships between composite roughness and Streptococcus mutans biofilm depth under shear in vitro.}, journal = {Journal of dentistry}, volume = {134}, number = {}, pages = {104535}, doi = {10.1016/j.jdent.2023.104535}, pmid = {37156358}, issn = {1879-176X}, mesh = {*Dental Materials/chemistry ; *Composite Resins/chemistry ; Bacterial Adhesion ; Streptococcus mutans ; Surface Properties ; Materials Testing ; Biofilms ; Glucose ; Sucrose/pharmacology ; }, abstract = {OBJECTIVE: To investigate the effect of substrate, surface roughness, and hydraulic residence time (HRT) on Streptococcus mutans biofilms growing on dental composites under conditions relevant to the oral cavity.

METHODS: Dental composites were prepared with varying amounts of polishing and incubated in a CDC bioreactor with an approximate shear of 0.4 Pa. S. mutans biofilms developed in the bioreactors fed sucrose or glucose and at 10-h or 40-h HRT for one week. Biofilms were characterized by confocal laser microscopy (CLM). Composite surface roughness was characterized by optical profilometry, and pre- and post-incubation composite surface fine structure and elemental composition were determined using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS).

RESULTS: Polishing had a significant impact on surface roughness, varying by a factor of 15 between the polished samples and the unpolished control. S. mutans biofilms grew statistically significantly thicker on the unpolished composites. Biofilm thickness was greater at shorter 10-h HRT compared to 40-h HRT. In most cases, biofilm thickness was not statistically significantly greater in sucrose-fed bioreactors than in glucose-fed bioreactors. SEM-EDS analysis did not identify any significant change in elemental composition after aging.

CONCLUSIONS: Accurate characterization of oral cavity biofilms must consider shear forces and the use of techniques that minimize alteration of the biofilm structure. Under shear, surface smoothness is the most important factor determining S. mutans biofilm thickness followed by HRT, while sucrose presence did not result in significantly greater biofilm thickness.

CLINICAL SIGNIFICANCE: The obvious patterns of S. mutans growth along sub-micron scale grooving created by the polishing process suggested that initial biofilm attachment occurred in the shear-protected grooves. These results suggest that fine polishing may help prevent the initial formation of S. mutans biofilms compared to unpolished/coarse polished composites.}, } @article {pmid37154695, year = {2023}, author = {de Lima, EJSP and Paz, WHP and Dávila Cardozo, NM and Boleti, APA and Silva, PSE and Mukoyama, LTH and da Silva, FMA and Costa, EV and Tavares, JF and Migliolo, L and Koolen, HHF}, title = {Anti-biofilm and anti-inflammatory active diterpene isolated from the fruit of Xylopia benthamii R.E.Fr.}, journal = {Natural product research}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/14786419.2023.2208357}, pmid = {37154695}, issn = {1478-6427}, abstract = {Xylopia benthamii (Annonaceae) is a plant with limited phytochemical and pharmacological evidence. Thus, using LC-MS/MS, we performed exploratory analyses of the fruit extract of X. benthamii, resulting in the tentative identification of alkaloids (1-7) and diterpenes (8-13). Through the application of chromatography techniques with the extract of X. benthamii, two kaurane diterpenes were isolated, xylopinic acid (9) and ent-15-oxo-kaur-16-en-19-oic acid (11). Their structures were established using spectroscopy (NMR 1D/2D) and mass spectrometry. The isolated compounds were submitted to anti-biofilm analysis against Acinetobacter baumannii, anti-neuroinflammatory and cytotoxic activity in BV-2 cells. Compound 11 (201.75 µM) inhibited 35% of bacterial biofilm formation and high anti-inflammatory activity in BV-2 (IC50 = 0.78 µM). In conclusion, the results demonstrated that compound 11 was characterized for the first time with pharmacological potential in the development of new alternatives for studies with neuroinflammatory diseases.}, } @article {pmid37154227, year = {2023}, author = {He, Y and Wang, X and Zhang, C and Sun, J and Xu, J and Li, D}, title = {Near-Infrared Light-Mediated Cyclodextrin Metal-Organic Frameworks for Synergistic Antibacterial and Anti-Biofilm Therapies.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {}, number = {}, pages = {e2300199}, doi = {10.1002/smll.202300199}, pmid = {37154227}, issn = {1613-6829}, support = {82102588//National Natural Science Foundation of China/ ; 82104086//National Natural Science Foundation of China/ ; 2021M700130//China Postdoctoral Science Foundation/ ; 232300421050//Natural Science Fund for Excellent Young Scholars of Henan Province/ ; HNSWJW2022007//Young and Middle-aged Discipline Leader of Henan Provincial Health Commission/ ; 2023HYTP042//Youth Talent Promotion Project of Henan Province/ ; SBGJ202102116//Key Projects of Medical Science and Technology of Henan Province/ ; 32320359//Youth Talent Innovation Team Support Program of Zhengzhou University/ ; LHGJ20210279//Joint Construction Projects of Medical Science and Technology of Henan Province/ ; }, abstract = {Bacterial infections pose a significant threat to global public health; therefore, the development of novel therapeutics is urgently needed. Herein, a controllable antibacterial nanoplatform utilizing cyclodextrin metal-organic frameworks (CD-MOFs) as a template to synthesize ultrafine silver nanoparticles (Ag NPs) in their porous structure is constructed. Subsequently, polydopamine (PDA) is encapsulated on the CD-MOFs' surface via dopamine polymerization to enhance the water stability and enable hyperthermia capacity. The resulting Ag@MOF@PDA generates localized hyperthermia and gradually releases Ag[+] to achieve long-term photothermal-chemical bactericidal capability. The release rate of Ag[+] can be accelerated by NIR-mediated heating in a controllable manner, quickly reaching the effective concentration and reducing the frequency of medication to avoid potential toxicity. In vitro experiments demonstrate that the combined antibacterial strategy can not only effectively kill both gram-negative and gram-positive bacteria, but also directly eradicate mature biofilms. In vivo results confirm that both bacterial- and biofilm-infected wounds treated with a combination of Ag@MOF@PDA and laser exhibit satisfactory recovery with minimal toxicity, displaying a superior therapeutic effect compared to other groups. Together, the results warrant that the Ag@MOF@PDA realizes synergistic antibacterial capacity and controllable release of Ag[+] to combat bacterial and biofilm infections, providing a potential antibiotic-free alternative in the "post-antibiotic era."}, } @article {pmid37154041, year = {2023}, author = {Yan, L and Zhang, S and Zhou, X and Tian, S}, title = {Anti-biofilm and bacteriostatic effects of three flavonoid compounds on Streptococcus mutans.}, journal = {Biofouling}, volume = {39}, number = {3}, pages = {245-256}, doi = {10.1080/08927014.2023.2209012}, pmid = {37154041}, issn = {1029-2454}, mesh = {Humans ; *Streptococcus mutans ; Biofilms ; *Dental Caries ; Anti-Bacterial Agents/pharmacology ; Flavonoids/pharmacology ; }, abstract = {Streptococcus mutans (S. mutans) is the main cariogenic pathogen associated with dental caries. Orientin-2''-O-β-L-galactoside, orientin and vitexin are natural flavonoids compound. In this study, the antibacterial ability of these flavonoids and their mechanisms in inhibiting S. mutans biofilm formation were investigated. Inhibition zone and 2-fold-dilution tests showed that these flavonoids exerted inhibitory effects on S. mutans. Phenol sulfuric acid method and lactate dehydrogenase (LDH) test revealed that they could reduce EPS formation and stimulate S. mutans to release LDH. Moreover, crystal violet and live/dead bacterial staining test showed that they inhibited biofilm formation. Finally, qRT-PCR test indicated that the down-regulated the transcription levels of spaP, srtA, brpA, gtfB and luxS genes of S. mutans. In conclusion, orientin-2''-O-β-L-galactoside, orientin and vitexin had antibacterial and anti-biofilm activities.}, } @article {pmid37153739, year = {2023}, author = {Wu, X and Qi, M and Liu, C and Yang, Q and Li, S and Shi, F and Sun, X and Wang, L and Li, C and Dong, B}, title = {Near-infrared light-triggered nitric oxide nanocomposites for photodynamic/photothermal complementary therapy against periodontal biofilm in an animal model.}, journal = {Theranostics}, volume = {13}, number = {7}, pages = {2350-2367}, pmid = {37153739}, issn = {1838-7640}, mesh = {Animals ; Nitric Oxide ; Reactive Oxygen Species ; *Photochemotherapy/methods ; Biofilms ; *Nanocomposites ; Anti-Bacterial Agents/pharmacology ; Models, Animal ; *Complementary Therapies ; }, abstract = {Background: Periodontal disease, an oral disease that initiates with plaque biofilm infection, affects 10% of the global population. Due to the complexity of tooth root anatomy, biofilm resistance and antibiotic resistance, traditional mechanical debridement and antibiotic removal of biofilms are not ideal. Nitric oxide (NO) gas therapy and its multifunctional therapy are effective methods to clear biofilms. However, large and controlled delivery of NO gas molecules is currently a great challenge. Methods: The core-shell structure of Ag2S@ZIF-90/Arg/ICG was developed and characterized in detail. The ability of Ag2S@ZIF-90/Arg/ICG to produce heat, ROS and NO under 808 nm NIR excitation was detected by an infrared thermal camera, probes and Griess assay. In vitro anti-biofilm effects were evaluated by CFU, Dead/Live staining and MTT assays. Hematoxylin-eosin staining, Masson staining and immunofluorescence staining were used to analyze the therapeutic effects in vivo. Results: Antibacterial photothermal therapy (aPTT) and antibacterial photodynamic therapy (aPDT) could be excited by 808 nm NIR light, and the produced heat and ROS further triggered the release of NO gas molecules simultaneously. The antibiofilm effect had a 4-log reduction in vitro. The produced NO caused biofilm dispersion through the degradation of the c-di-AMP pathway and improved biofilm eradication performance. In addition, Ag2S@ZIF-90/Arg/ICG had the best therapeutic effect on periodontitis and NIR II imaging ability in vivo. Conclusions: We successfully prepared a novel nanocomposite with NO synergistic aPTT and aPDT. It had an outstanding therapeutic effect in treating deep tissue biofilm infection. This study not only enriches the research on compound therapy with NO gas therapy but also provides a new solution for other biofilm infection diseases.}, } @article {pmid37153005, year = {2023}, author = {Teixeira, ABV and Valente, MLDC and Sessa, JPN and Gubitoso, B and Schiavon, MA and Dos Reis, AC}, title = {Adhesion of biofilm, surface characteristics, and mechanical properties of antimicrobial denture base resin.}, journal = {The journal of advanced prosthodontics}, volume = {15}, number = {2}, pages = {80-92}, pmid = {37153005}, issn = {2005-7806}, abstract = {PURPOSE: This study incorporated the nanomaterial, nanostructured silver vanadate decorated with silver nanoparticles (AgVO3), into heat-cured resin (HT) at concentrations of 2.5%, 5%, and 10% and compared the adhesion of multispecies biofilms, surface characteristics, and mechanical properties with conventional heat-cured (HT 0%) and printed resins.

MATERIALS AND METHODS: AgVO3 was incorporated in mass into HT powder. A denture base resin was used to obtain printed samples. Adhesion of a multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans was evaluated by colony-forming units per milliliter (CFU/mL) and metabolic activity. Wettability, roughness, and scanning electron microscopy (SEM) were used to assess the physical characteristics of the surface. The mechanical properties of flexural strength and elastic modulus were tested.

RESULTS: HT 10%-AgVO3 showed efficacy against S. mutans; however, it favored C. albicans CFU/mL (P < .05). The printed resin showed a higher metabolically active biofilm than HT 0% (P < .05). There was no difference in wettability or roughness between groups (P > .05). Irregularities on the printed resin surface and pores in HT 5%-AgVO3 were observed by SEM. HT 0% showed the highest flexural strength, and the resins incorporated with AgVO3 had the highest elastic modulus (P < .05).

CONCLUSION: The incorporation of 10% AgVO3 into heat-cured resin provided antimicrobial activity against S. mutans in a multispecies biofilm did not affect the roughness or wettability but reduced flexural strength and increased elastic modulus. Printed resin showed higher irregularity, an active biofilm, and lower flexural strength and elastic modulus than heat-cured resin.}, } @article {pmid37152853, year = {2023}, author = {Zargar, N and Parhizkar, A and Nasiri, MJ and Saedi, S}, title = {Antibacterial Efficacy of Polymer-Coated Ceramic Microparticles Loaded with a Modified Combination of Antibiotics on the Enterococcus faecalis Biofilm.}, journal = {Iranian endodontic journal}, volume = {18}, number = {2}, pages = {85-90}, pmid = {37152853}, issn = {2008-2746}, abstract = {INTRODUCTION: Nano-technology applied for the local delivery of different agents and/or drugs has made its path to endodontics. In the current study, the antibacterial efficacy of biopolymer-coated ceramic microparticles loaded with a modified combination of triple antibiotics, i.e. Penicillin G, Metronidazole and Ciprofloxacin (PMC), was evaluated against two strains of Enterococcus faecalis (E.faecalis); a standard clinical strain obtained from previously root-filled teeth with persistent periapical lesions, and compared to the most common antimicrobials used in endodontics.

METHODS AND MATERIALS: After synthesis of the polymer-coated microparticles loaded with antibiotics, the 21-day release of antibiotics were evaluated and a stock solution was produced using the maximum released amount of drugs and distilled water. The antibacterial activity of PMC, triple antibiotic paste (TAP), calcium hydroxide (CH), chlorhexidine (CHX) and sodium hypochlorite (NaOCl) against two bacterial strains was determined using "Minimum Inhibitory Concentration" and "Agar Diffusion Test". Additionally, "Microtiter Plate Assay" was performed to assess anti-biofilm properties.

RESULTS: Minimum inhibitory concentration values reported for TAP and PMC were 1/256. PMC showed the maximum diameter of growth inhibition in both strains (33 mm and 35 mm), while CH had the minimum diameters (13 mm and13 mm). Based on microtiter plate assay, TAP showed higher biofilm formation than PMC. Biofilm formation was higher in the standard strain for PMC; however, NaOCl, CHX and CH completely inhibited biofilm formation.

CONCLUSIONS: Based on the findings of the present study, it could be concluded that PMC and TAP were the most effective medicaments against E.faecalis in its planktonic form; however, none could inhibit its biofilm formation. Further studies using larger sample size and "Confocal Scanning Laser Microscopy" are recommended.}, } @article {pmid37152752, year = {2023}, author = {van Dun, SCJ and Verheul, M and Pijls, BGCW and van Prehn, J and Scheper, H and Galli, F and Nibbering, PH and de Boer, MGJ}, title = {Influence of surface characteristics of implant materials on MRSA biofilm formation and effects of antimicrobial treatment.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1145210}, pmid = {37152752}, issn = {1664-302X}, abstract = {INTRODUCTION: One of the main causes of treatment failure in bacterial prosthetic joint infections (PJI) is biofilm formation. The topography of the biofilm may be associated with susceptibility to antimicrobial treatment. The aims of this study were to assess differences in topography of biofilms on different implant materials and the correlation thereof with susceptibility to antimicrobial treatment.

METHODS: Methicillin-resistant Staphylococcus aureus (MRSA) 7-day mature biofilms were generated on disks made from titanium alloys (Ti-6Al-7Nb and Ti-6Al-4V), synthetic polymer and orthopedic bone cement, commonly used in implant surgery. The surface topography of these implant materials and the biofilms cultured on them was assessed using atomic force microscopy. This provided detailed images, as well as average roughness (Ra) and peak-to-valley roughness (Rt) values in nanometers, of the biofilm and the material surfaces. Bacterial counts within biofilms were assessed microbiologically. Antimicrobial treatment of biofilms was performed by 24-h exposure to the combination of rifampicin and ciprofloxacin in concentrations of 1-, 5- and 10-times the minimal bactericidal concentration (MBC). Finally, treatment-induced differences in bacterial loads and their correlation with biofilm surface parameters were assessed.

RESULTS: The biofilm surfaces on titanium alloys Ti-6Al-7Nb (Ra = 186 nm) and Ti-6Al-4V (Ra = 270 nm) were less rough than those of biofilms on silicone (Ra = 636 nm). The highest roughness was observed for biofilms on orthopedic bone cement with an Ra of 1,551 nm. Interestingly, the roughness parameters of the titanium alloys themselves were lower than the value for silicone, whereas the surface of the bone cement was the roughest. Treatment with 1- and 5-times the MBC of antibiotics resulted in inter-material differences in colony forming units (CFU) counts, ultimately showing comparable reductions of 2.4-3.0 log CFU/mL at the highest tested concentration. No significant differences in bacterial loads within MRSA biofilms were observed between the various implant materials, upon exposure to increasing concentrations of antibiotics.

DISCUSSION: The surface parameters of MRSA biofilms were determined by those of the implant materials on which they were formed. The antibiotic susceptibility of MRSA biofilms on the various tested implant materials did not differ, indicating that the efficacy of antibiotics was not affected by the roughness of the biofilm.}, } @article {pmid37152721, year = {2023}, author = {Breser, ML and Tisera, L and Orellano, MS and Bohl, LP and Isaac, P and Bianco, I and Porporatto, C}, title = {Chitosan can improve antimicrobial treatment independently of bacterial lifestyle, biofilm biomass intensity and antibiotic resistance pattern in non-aureus staphylococci (NAS) isolated from bovine clinical mastitis.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1167693}, pmid = {37152721}, issn = {1664-302X}, abstract = {Bovine mastitis is the most frequent and costly disease that affects dairy cattle. Non-aureus staphylococci (NAS) are currently one of the main pathogens associated with difficult-to-treat intramammary infections. Biofilm is an important virulence factor that can protect bacteria against antimicrobial treatment and prevent their recognition by the host's immune system. Previously, we found that chronic mastitis isolates which were refractory to antibiotic therapy developed strong biofilm biomass. Now, we evaluated the influence of biofilm biomass intensity on the antibiotic resistance pattern in strong and weak biofilm-forming NAS isolates from clinical mastitis. We also assessed the effect of cloxacillin (Clx) and chitosan (Ch), either alone or in combination, on NAS isolates with different lifestyles and abilities to form biofilm. The antibiotic resistance pattern was not the same in strong and weak biofilm producers, and there was a significant association (p ≤ 0.01) between biofilm biomass intensity and antibiotic resistance. Bacterial viability assays showed that a similar antibiotic concentration was effective at killing both groups when they grew planktonically. In contrast, within biofilm the concentrations needed to eliminate strong producers were 16 to 128 times those needed for weak producers, and more than 1,000 times those required for planktonic cultures. Moreover, Ch alone or combined with Clx had significant antimicrobial activity, and represented an improvement over the activity of the antibiotic on its own, independently of the bacterial lifestyle, the biofilm biomass intensity or the antibiotic resistance pattern. In conclusion, the degree of protection conferred by biofilm against antibiotics appears to be associated with the intensity of its biomass, but treatment with Ch might be able to help counteract it. These findings suggest that bacterial biomass should be considered when designing new antimicrobial therapies aimed at reducing antibiotic concentrations while improving cure rates.}, } @article {pmid37151214, year = {2023}, author = {Naaz, S and Sakib, N and Houserova, D and Badve, R and Crucello, A and Borchert, GM}, title = {Characterization of a novel sRNA contributing to biofilm formation in Salmonella enterica serovar Typhimurium.}, journal = {microPublication biology}, volume = {2023}, number = {}, pages = {}, pmid = {37151214}, issn = {2578-9430}, abstract = {Small RNAs (sRNAs) are short noncoding RNAs of ~50-200 nucleotides believed to primarily function in regulating crucial activities in bacteria during periods of cellular stress. This study examined the relevance of specific sRNAs on biofilm formation in nutrient starved Salmonella enterica serovar Typhimurium. Eight unique sRNAs were selected for deletion primarily based on their genomic location and/or putative targets. Quantitative and qualitative analyses confirm one of these, sRNA1186573, is required for efficient biofilm formation in S. enterica further highlighting the significance of sRNAs during Salmonella stress response.}, } @article {pmid37150474, year = {2023}, author = {Premetis, GE and Georgakis, ND and Stathi, A and Labrou, NE}, title = {Metaviromics analysis of marine biofilm reveals a glycoside hydrolase endolysin with high specificity towards Acinetobacter baumannii.}, journal = {Biochimica et biophysica acta. Proteins and proteomics}, volume = {1871}, number = {4}, pages = {140918}, doi = {10.1016/j.bbapap.2023.140918}, pmid = {37150474}, issn = {1878-1454}, mesh = {Humans ; *Acinetobacter baumannii/genetics ; Glycoside Hydrolases/genetics ; Escherichia coli ; *Anti-Infective Agents/pharmacology ; Biofilms ; }, abstract = {Multidrug-resistant (MDR) bacteria are a growing threat to the public health. Among them, the Gram-negative Acinetobacter baumannii is considered today as the most dangerous MDR pathogen. Phage-derived endolysins are peptidoglycan (PG) hydrolytic enzymes that can function as effective tools in the fight against MDR bacteria. In the present work, the viral diversity of a marine environmental sample (biofilm), formed near an industrial zone, was mined for the identification of a putative endolysin (AbLys2) that belongs to the glycoside hydrolase family 24 (GH24, EC 3.2.1.17). The coding sequence of AbLys2 was cloned and expressed in E. coli. The lytic activity and specificity of the recombinant enzyme were evaluated against suspensions of a range of Gram-positive and Gram-negative human pathogens using turbidity assays. AbLys2 displayed enhanced selectivity towards A. baumannii cells, compared to other bacteria. Kinetics analysis was carried out to characterize the dependence of its lytic activity on pH and showed that the enzyme exhibits its maximal activity at pH 5.5. Thermostability analysis showed that AbLys2 displays melting temperature Tm 47.1 °C. Florescence microscopy and cell viability assays established that AbLys2 is active towards live cultures of A. baumannii cells with an inhibitory concentration IC50 3.41 ± 0.09 μM. Molecular modeling allowed the prediction of important amino acid residues involved in catalysis. The results of the present study suggest that AbLys2 provides efficient lytic and antimicrobial activity towards A. baumannii cells and therefore is a promising new antimicrobial against this pathogen.}, } @article {pmid37150370, year = {2023}, author = {Lu, T and Han, X and Wang, H and Zhang, Z and Lu, S}, title = {Multi-functional bio-film based on sisal cellulose nanofibres and carboxymethyl chitosan with flame retardancy, water resistance, and self-cleaning for fire alarm sensors.}, journal = {International journal of biological macromolecules}, volume = {242}, number = {Pt 1}, pages = {124740}, doi = {10.1016/j.ijbiomac.2023.124740}, pmid = {37150370}, issn = {1879-0003}, mesh = {*Chitosan ; *Nanofibers ; *Agave ; Cellulose ; Extreme Environments ; Phytic Acid ; }, abstract = {Flexible and environmentally friendly bio-based films have attracted significant attention as next-generation fire-responsive sensors. However, the low structural stability, durability, and flame retardancy of pure bio-based films limit their application in outdoor and extreme environments. Here, we report the design of a sustainable bio-based composite film assembled from carboxymethyl-modified sisal fibre microcrystals (C-MSF), carboxymethyl chitosan (CMC), graphene nanosheets (GNs), phytic acid (PA), and trivalent iron ions (Fe[3+]). Cross-linking between Fe[3+] and the C-MSF/CMC matrix and the formation of PA-Fe[3+] complexes on the surface of the film imparted excellent mechanical properties, chemical stability, self-cleaning ability, and flame retardancy to the bio-film. Furthermore, the bio-film produced a reversible and sensitive response to temperature at 55.3-214.1 °C, and a fire alarm system made from the bio-film had a fire-response time of 4.6 s. In addition, the char layer of the bio-film retained a stable cyclic response to temperature, enabling it to serve as a fire resurgence sensor with a response time of 2.3 s and recovery time of 11.2 s. This work provides a simple pathway for the fabrication of self-cleaning, flame retardant, and water-resistant bio-films that can be assembled into fire alarm systems for the real-time monitoring of fire accidents and resurgence.}, } @article {pmid37150060, year = {2023}, author = {Laconi, A and Tolosi, R and Drigo, I and Bano, L and Piccirillo, A}, title = {Association between ability to form biofilm and virulence factors of poultry extra-intestinal Campylobacter jejuni and Campylobacter coli.}, journal = {Veterinary microbiology}, volume = {282}, number = {}, pages = {109770}, doi = {10.1016/j.vetmic.2023.109770}, pmid = {37150060}, issn = {1873-2542}, mesh = {Animals ; *Campylobacter jejuni ; *Campylobacter coli ; Poultry/microbiology ; Virulence Factors/genetics ; *Campylobacter/genetics ; *Campylobacter Infections/veterinary/microbiology ; }, abstract = {Campylobacter species are known to be able to produce biofilm, which represents an ideal protective environment for the maintenance of such fragile bacteria. Since the genetic mechanisms promoting biofilm formation are still poorly understood, in this study we assessed the ability of C. jejuni (n = 7) and C. coli (n = 3) strains isolated from diseased poultry, and previously characterized by whole genome sequencing, to form biofilm. The in vitro analyses were carried out by using a microtiter based protocol including biofilm culturing and fixation, staining with crystal violet, and measurement of the optical density (OD570). The ability to form biofilm was categorized into four classes (no, weak, moderate, and strong producers). Potential correlations between OD570 and the presence/absence of virulence determinants were examined. The C. jejuni were classified as no (n = 3), weak (n = 2), and moderate (n = 2) biofilm producers; however, all possessed genes involved in chemotaxis, adhesion, and invasion to the host cells. No genes present exclusively in biofilm producers or in non-biofilm producers were identified. All C. coli were classified as weak producers and showed a similar set of virulence genes between each other. A trend of increased mean OD570 was observed in the presence of flaA and maf7 genes. No association between biofilm production classes and the explanatory variables considered was observed. The results of this study suggest that further investigations are needed to better identify and characterize the genetic determinants involved in extra-intestinal Campylobacter biofilm formation.}, } @article {pmid37149027, year = {2023}, author = {Bao, HX and Wang, HL and Wang, ST and Sun, YL and Zhang, XN and Cheng, HY and Qian, ZM and Wang, AJ}, title = {Response of sulfur-metabolizing biofilm to external sulfide in element sulfur-based denitrification packed-bed reactor.}, journal = {Environmental research}, volume = {231}, number = {Pt 1}, pages = {116061}, doi = {10.1016/j.envres.2023.116061}, pmid = {37149027}, issn = {1096-0953}, mesh = {*Denitrification ; *Bioreactors ; Sulfides ; Sulfur ; Biofilms ; }, abstract = {Dosing sulfide into the sulfur-packed-bed (S[0]PB) has great potential to enhance the denitrification efficiency by providing compensatory electron donors, however, the response of sulfur-metabolizing biofilm to various sulfide dosages has never been investigated. In this study, the S[0]PB reactor was carried out with increasing sulfide dosages by 3.6 kg/m[3]/d, presenting a decreasing effluent nitrate from 14.2 to 2.7 mg N/L with accelerated denitrification efficiency (k: 0.04 to 0.27). However, 6.5 mg N/L of nitrite accumulated when the sulfide dosage exceeded 0.9 kg/m[3]/d (optimum value). The increasing electron export contribution of sulfide a maximum of 85.5% illustrated its competition with the in-situ sulfur. Meanwhile, over-dosing sulfide caused serious biofilm expulsion with significant decreases in the total biomass, live cell population, and ATP by 90.2%, 86.7%, and 54.8%, respectively. This study verified the capacity of dosing sulfide to improve the denitrification efficiency in S[0]PB but alerted the negative effect of exceeded dosing.}, } @article {pmid37148923, year = {2023}, author = {Shi, C and Zheng, L and Lu, Z and Zhang, X and Bie, X}, title = {The global regulator SpoVG regulates Listeria monocytogenes biofilm formation.}, journal = {Microbial pathogenesis}, volume = {180}, number = {}, pages = {106144}, doi = {10.1016/j.micpath.2023.106144}, pmid = {37148923}, issn = {1096-1208}, mesh = {*Listeria monocytogenes ; Temperature ; Bacterial Proteins/metabolism ; Biofilms ; Virulence/genetics ; }, abstract = {Biofilms provide a suitable environment for L. monocytogenes and are the cause of enormous risks in the food industry. SpoVG is a global regulatory factor that plays a vital role in physiological activity of L. monocytogenes. We constructed spoVG mutant strains to investigate the effects of these mutants on L. monocytogenes biofilms. The results show that L. monocytogenes biofilm formation was decreased by 40%. Furthermore, we measured biofilm related phenotypes to study the regulation of SpoVG. The motility capacity of L. monocytogenes was found to decrease after the deletion of spoVG. The cell surface properties changed in the spoVG mutant strains, with an increase in both the cell surface hydrophobicity and the auto-aggregation capacity after spoVG deletion. SpoVG mutant strains were found to be more sensitive to antibiotics, and had a reduced tolerance to inappropriate pH, salt stress and low temperature. The RT-qPCR results showed that SpoVG effectively regulated the expression of genes related to quorum sensing, flagella, virulence and stress factors. These findings suggest that spoVG has potential as a target to decrease biofilm formation and control L. monocytogenes contamination in the food industry.}, } @article {pmid37148370, year = {2023}, author = {Lv, Z and Yin, S and Jiang, K and Wang, W and Luan, Y and Wu, S and Shi, J and Li, Z and Ma, X and Wang, Z and Yan, H}, title = {The whole-cell proteome shows the characteristics of macrolides-resistant Bordetella pertussis in China linked to the biofilm formation.}, journal = {Archives of microbiology}, volume = {205}, number = {6}, pages = {219}, pmid = {37148370}, issn = {1432-072X}, support = {82172312//Natural Science Foundation of China under Grant/ ; 2021SF-003//Key Research and Development Program of Shaanxi Province under Grant/ ; 20YXYJ0006(1)//Xi'an Science and technology project under Grant/ ; }, mesh = {Humans ; *Bordetella pertussis/genetics ; Macrolides/pharmacology ; *Whooping Cough ; Proteome ; Proteomics ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The macrolides-resistant Bordetella pertussis (MR-Bp) isolates in China evolved from the ptxP1/fhaB3 allele and rapidly became predominant, suggestive of an adaptive transmission ability. This was different from the global prevalent ptxP3 strains, in which MR-Bp was rarely reported. The study aimed to determine the underlying mechanism responsible for fitness and resistance in these two strains. We identify proteomic differences between ptxP1/fhaB3 and ptxP3/fhaB1 strains using tandem mass tag (TMT)-based proteomics. We then performed in-depth bioinformatic analysis to determine differentially expressed genes (DEGs), followed by gene ontology (GO), and protein-protein interaction (PPI) network analysis. Further parallel reaction monitoring (PRM) analysis confirmed the expression of four target proteins. Finally, the crystal violet method was used to determine biofilm-forming ability. The results showed that the main significantly different proteins between the two represent isolates were related to biofilm formation. Furthermore, we have confirmed that ptxP1/fhaB3 showed hyperbiofilm formation in comparison with ptxP3/fhaB1. It is suggested that the resistance and adaptability of ptxP1/fhaB3 strains may be related to the formation of biofilm through proteomics. In a word, we determined the significantly different proteins between the ptxP1/fhaB3 and ptxP3/fhaB1 strains through whole-cell proteome, which were related to biofilm formation.}, } @article {pmid37146493, year = {2023}, author = {Masoudi-Sobhanzadeh, Y and Pourseif, MM and Khalili-Sani, A and Jafari, B and Salemi, A and Omidi, Y}, title = {Deciphering anti-biofilm property of Arthrospira platensis-origin peptides against Staphylococcusaureus.}, journal = {Computers in biology and medicine}, volume = {160}, number = {}, pages = {106975}, doi = {10.1016/j.compbiomed.2023.106975}, pmid = {37146493}, issn = {1879-0534}, mesh = {Molecular Docking Simulation ; *Staphylococcus aureus/metabolism ; Peptides/chemistry ; *Anti-Infective Agents/chemistry ; }, abstract = {Arthrospira platensis is a valuable natural health supplement consisting of various types of vitamins, dietary minerals, and antioxidants. Although different studies have been conducted to explore the hidden benefits of this bacterium, its antimicrobial property has been poorly understood. To decipher this important feature, here, we extended our recently introduced optimization algorithm (Trader) for aligning amino acid sequences associated with the antimicrobial peptides (AMPs) of Staphylococcus aureus and A.platensis. As a result, similar amino acid sequences were identified, and several candidate peptides were generated accordingly. The obtained peptides were then filtered based on their potential biochemical and biophysical properties, and their 3D structures were simulated based on homology modeling techniques. Next, to investigate how the generated peptides can interact with S. aureus proteins (i.e., heptameric state of the hly and homodimeric form of the arsB), molecular docking approaches were used. The results indicated that four peptides included better molecular interactions relative to the other generated ones in terms of the number/average length of hydrogen bonds and hydrophobic interactions. Based on the outcomes, it can be concluded that the antimicrobial property of A.platensis might be associated with its capability in disturbing the membrane of pathogens and their functions.}, } @article {pmid37144188, year = {2023}, author = {Adhikari, S and Sharma Regmi, R and Sapkota, S and Khadka, S and Patel, N and Gurung, S and Thapa, D and Bhattarai, P and Sapkota, P and Devkota, R and Ghimire, A and Rijal, KR}, title = {Multidrug resistance, biofilm formation and detection of bla CTX-M and bla VIM genes in E. coli and Salmonella isolates from chutney served at the street-food stalls of Bharatpur, Nepal.}, journal = {Heliyon}, volume = {9}, number = {5}, pages = {e15739}, pmid = {37144188}, issn = {2405-8440}, abstract = {Antimicrobial resistance (AMR) amid the bacteria found in ready-to-eat foods is a grave concern today warranting an immediate intervention. The current study was undertaken to explore the status of AMR in E. coli and Salmonella species in ready-to-eat Chutney samples (n = 150) served at the street food stalls in Bharatpur, Nepal, with a major focus on detecting extended-spectrum β-lactamase (ESBL) and metallo β-lactamase (MBL) genes along with biofilm formation. Average viable counts, coliform counts, and Salmonella Shigella counts were 1.33 × 10[6]±141481.4, 1.83 × 10[5]±91303.6, and 1.24 × 10[5]±63933.19 respectively. Out of 150 samples, 41 (27.33%) harbored E. coli, of which 7 were E. coli O157:H7; whereas Salmonella spp. were found in 31 (20.67%) samples. Bacterial contamination of Chutney by E. coli and Salmonella and ESBL-production were both found significantly affected by different sources of water used, personal hygiene and literacy rate of the vendors as well as by the type of cleaning materials used to wash knives and chopping boards (P < 0.05). Antibiotic susceptibility testing revealed that imipenem was the most effective drug against both types of bacterial isolates. Additionally, 14 (45.16%) Salmonella isolates and 27 (65.85%) E. coli isolates were found to be multi-drug resistant (MDR). Total ESBL (bla CTX-M) producers reported were 4 (12.90%) Salmonella spp. and 9 (21.95%) E. coli. Only 1 (3.23%) Salmonella spp. and 2 (4.88%) E. coli isolates were bla VIM gene carriers. Dissemination of knowledge of personal hygiene amongst the street vendors and consumer awareness regarding ready-to-eat foods are crucial factors that can be suggested to curtail the emergence and transmission of food-borne pathogens.}, } @article {pmid37142893, year = {2023}, author = {Paul, P and Sarkar, S and Dastidar, DG and Shukla, A and Das, S and Chatterjee, S and Chakraborty, P and Tribedi, P}, title = {1, 4-naphthoquinone efficiently facilitates the disintegration of pre-existing biofilm of Staphylococcus aureus through eDNA intercalation.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {37142893}, issn = {1874-9356}, abstract = {1, 4-naphthoquinone, a plant-based quinone derivative, has gained much attention for its effectiveness against several biofilm-linked diseases. The biofilm inhibitory effect of 1, 4-naphthoquinone against Staphylococcus aureus has already been reported in our previous study. We observed that the extracellular DNA (eDNA) could play an important role in holding the structural integrity of the biofilm. Hence, in this study, efforts have been directed to examine the possible interactions between 1, 4-naphthoquinone and DNA. An in silico analysis indicated that 1, 4-naphthoquinone could interact with DNA through intercalation. To validate the same, UV-Vis spectrophotometric analysis was performed in which a hypochromic shift was observed when the said molecule was titrated with calf-thymus DNA (CT-DNA). Thermal denaturation studies revealed a change of 8℃ in the melting temperature (Tm) of CT-DNA when complexed with 1, 4-naphthoquinone. The isothermal calorimetric titration (ITC) assay revealed a spontaneous intercalation between CT-DNA and 1, 4-naphthoquinone with a binding constant of 0.95 ± 0.12 × 10[8]. Furthermore, DNA was run through an agarose gel electrophoresis with a fixed concentration of ethidium bromide and increasing concentrations of 1, 4-naphthoquinone. The result showed that the intensity of ethidium bromide-stained DNA got reduced concomitantly with the gradual increase of 1, 4-naphthoquinone suggesting its intercalating nature. To gain further confidence, the pre-existing biofilm was challenged with ethidium bromide wherein we observed that it could also show biofilm disintegration. Therefore, the results suggested that 1, 4-naphthoquinone could exhibit disintegration of the pre-existing biofilm of Staphylococcus aureus through eDNA intercalation.}, } @article {pmid37141849, year = {2023}, author = {Wang, J and Wang, Y and Lou, H and Wang, W}, title = {AlgU controls environmental stress adaptation, biofilm formation, motility, pyochelin synthesis and antagonism potential in Pseudomonas protegens SN15-2.}, journal = {Microbiological research}, volume = {272}, number = {}, pages = {127396}, doi = {10.1016/j.micres.2023.127396}, pmid = {37141849}, issn = {1618-0623}, mesh = {*Bacterial Proteins/metabolism ; *Phenols ; Sigma Factor/genetics/metabolism ; Pseudomonas aeruginosa/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; }, abstract = {Pseudomonas protegens is a typical plant-growth-promoting rhizobacterium that can serve as an agricultural biocontrol agent. The extracytoplasmic function (ECF) sigma factor AlgU is a global transcription regulator controlling stress adaption and virulence in Pseudomonas aeruginosa and Pseudomonas syringae. Meanwhile, the regulatory role of AlgU in the biocontrol ability of P.protegens has been poorly studied. In this study, deletion mutations of algU and its antagonist coding gene mucA were constructed to investigate the function of AlgU in P.protegens SN15-2 via phenotypic experiment and transcriptome sequencing analysis. On the basis of phenotypic analyses, it was concluded that the AlgU whose transcription was induced by osmotic stress and oxidative stress positively regulated biofilm formation and tolerance towards osmotic, heat, and oxidation stresses, while it negatively regulated motility, pyochelin synthesis, and the ability to inhibit pathogens. On the basis of the RNA-seq analysis, compared to the wild-type strain, 12 genes were significantly upregulated and 77 genes were significantly downregulated in ΔalgU, while 407 genes were significantly upregulated and 279 genes were significantly downregulated in ΔmucA, indicating the involvement of AlgU in several cellular processes, mainly related to resistance, carbohydrate metabolism, membrane formation, alginate production, the type VI secretion system, flagella motility and pyochelin production. Our findings provide insights into the important role of AlgU of P.protegens in biocontrol, which is of value in improving the biocontrol ability of P.protegens.}, } @article {pmid37141712, year = {2023}, author = {Yan, H and Zhang, Q and Wang, Y and Cui, X and Liu, Y and Yu, Z and Xu, S and Ruan, R}, title = {Rice straw as microalgal biofilm bio-carrier: Effects of indigenous microorganisms on rice straw and microalgal biomass production.}, journal = {Journal of environmental management}, volume = {341}, number = {}, pages = {118075}, doi = {10.1016/j.jenvman.2023.118075}, pmid = {37141712}, issn = {1095-8630}, mesh = {*Chlorella ; *Microalgae/metabolism ; *Oryza ; Biomass ; Biofilms ; }, abstract = {Microalgal biofilm cultivation is a promising method for efficient microalgae production. However, expensive, difficult-to-obtain and non-durable carriers hinder its up-scaling. This study adopted both sterilized and unsterilized rice straw (RS) as a carrier for the development of microalgal biofilm, with polymethyl methacrylate as control. The biomass production and chemical composition of Chlorella sorokiniana, as well as the microbial community composition during cultivation were examined. The physicochemical properties of RS before and after utilized as carrier were investigated. The biomass productivity of unsterilized RS biofilm exceeded that of suspended culture by 4.85 g m[-2]·d[-1]. The indigenous microorganisms, mainly fungus, could effectively fixed microalgae to the bio-carrier and enhance its biomass production. They could also degrade RS into dissolved matters for microalgal utilization, leading to the physicochemical properties change of RS in the direction which favored its energy conversion. This study showed that RS can be used effectively as a microalgal biofilm carrier, thus presenting a new possibility for the recycling of rice straw.}, } @article {pmid37140860, year = {2023}, author = {Díaz, O and González, E and Vera, L and Fernández, LJ and Díaz-Marrero, AR and Fernández, JJ}, title = {Recirculating packed-bed biofilm photobioreactor combined with membrane ultrafiltration as advanced wastewater treatment.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {27}, pages = {69977-69990}, pmid = {37140860}, issn = {1614-7499}, support = {PID2019-109476RB-C21//Ministerio de Ciencia e Innovación/ ; }, mesh = {Photobioreactors/microbiology ; Wastewater ; Ultrafiltration ; Nitrification ; Biofilms ; *Water Purification ; *Microalgae ; Biomass ; Nitrogen ; Bioreactors ; Denitrification ; }, abstract = {Packed-bed biofilm photobioreactor combined with ultrafiltration membrane was investigated for intensifying the process for secondary wastewater effluent treatment. Cylindrical glass carriers were used as supporting material for the microalgal-bacterial biofilm, which developed from indigenous microbial consortium. Glass carriers allowed adequate growth of the biofilm with limited suspended biomass. Stable operation was achieved after a start-up period of 1000 h, where supernatant biopolymer clusters were minimized and complete nitrification was observed. After that time, biomass productivity was 54 ± 18 mg·L[-1]·day[-1]. Green microalgae Tetradesmus obliquus and several strains of heterotrophic nitrification-aerobic denitrification bacteria and fungi were identified. Combined process exhibited COD, nitrogen and phosphorus removal rates of 56 ± 5%, 12 ± 2% and 20 ± 6%, respectively. Membrane fouling was mainly caused by biofilm formation, which was not effectively mitigated by air-scouring aided backwashing.}, } @article {pmid37140461, year = {2023}, author = {Jiang, X and Kang, R and Yu, T and Jiang, X and Chen, H and Zhang, Y and Li, Y and Wang, H}, title = {Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0030023}, pmid = {37140461}, issn = {2165-0497}, mesh = {*Listeria monocytogenes/metabolism ; Histidine Kinase ; Biofilms ; Quorum Sensing ; DNA ; Bacterial Proteins/metabolism ; }, abstract = {The Agr quorum sensing (QS) system is known to contribute to biofilm formation in Listeria monocytogenes. Cinnamaldehyde, a natural food preservative, is considered an inhibitor of Agr-mediated QS in L. monocytogenes. However, the exact mechanism by which cinnamaldehyde acts on Agr remains unclear. In this study, we assessed the effects of cinnamaldehyde on the histidine kinase AgrC and the response regulator AgrA in the Agr system. AgrC kinase activity was not influenced by cinnamaldehyde, and binding between AgrC and cinnamaldehyde was not observed when microscale thermophoresis (MST) was performed, indicating that AgrC was not the target of cinnamaldehyde. AgrA is specifically bound to the agr promoter (P2) to activate the transcription of the Agr system. However, AgrA-P2 binding was prevented by cinnamaldehyde. The interaction between cinnamaldehyde and AgrA was further confirmed with MST. Two conserved amino acids, Asn-178 and Arg-179, located in the LytTR DNA-binding domain of AgrA, were identified as the key sites for cinnamaldehyde-AgrA binding by alanine mutagenesis and MST. Coincidentally, Asn-178 was also involved in the AgrA-P2 interaction. Taken together, these results suggest that cinnamaldehyde acts as a competitive inhibitor of AgrA in AgrA-P2 binding, which leads to suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. IMPORTANCE Listeria monocytogenes can form biofilms on various food contact surfaces, posing a serious threat to food safety. Biofilm formation of L. monocytogenes is positively regulated by the Agr quorum sensing system. Thus, an alternative strategy for controlling L. monocytogenes biofilms is interfering with the Agr system. Cinnamaldehyde is considered an inhibitor of the L. monocytogenes Agr system; however, its exact mechanism of action is still unclear. Here, we found that AgrA (response regulator), rather than AgrC (histidine kinase), was the target of cinnamaldehyde. The conserved Asn-178 in the LytTR DNA-binding domain of AgrA was involved in cinnamaldehyde-AgrA and AgrA-P2 binding. Therefore, the occupation of Asn-178 by cinnamaldehyde suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. Our findings could provide a better understanding of the mechanism by which cinnamaldehyde inhibits L. monocytogenes biofilm formation.}, } @article {pmid37140383, year = {2023}, author = {Ding, Y and Liu, G and Liu, S and Li, X and Xu, K and Liu, P and Cai, K}, title = {A Multifunction Hydrogel-Coating Engineered Implant for Rescuing Biofilm Infection and Boosting Osseointegration by Macrophage-Related Immunomodulation.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2300722}, doi = {10.1002/adhm.202300722}, pmid = {37140383}, issn = {2192-2659}, support = {2022YFB3804400//State Key Project of Research and Development/ ; 32171327//National Natural Science Foundation of China/ ; 51825302//National Natural Science Foundation of China/ ; cstc2021jcyj-cxttX0002//Natural Science Foundation of Chongqing/ ; }, abstract = {Innovative methodologies combined with scavenging reactive oxygen species (ROS), alleviating oxidative stress damage and promoting macrophage polarization to M2 phenotype may be ideal for remodeling implant-infected bone tissue. Herein, a functionalization strategy for doping Tannic acid-d-tyrosine nanoparticles with photothermal profile into the hydrogel coating composed of konjac gum and gelatin on the surface of titanium (Ti) substrate is accurately constructed. The prepared hydrogel coating exhibits excellent properties of eliminating biofilm and killing planktonic bacteria, which is based on increasing susceptibility to bacteria by the photothermal effect, biofilm-dissipation effect of D-tyrosine, as well as the bactericidal effect of tannic acid. In addition, the modified Ti substrate has effectively alleviated proinflammatory responses by scavenging intracellular excessive ROS and guiding macrophages polarization toward M2. More interesting, conditioned medium from macrophage indicates that paracrine is conducive to osteogenic proliferation and differentiation of mesenchymal stem cells. Results from rat model of femur infection in vivo demonstrate that the modified Ti implant significantly eliminates the residual bacteria, relieves inflammation, mediates macrophage polarization, and accelerates osseointegration. Altogether, this study exhibits a new perspective for the development of advanced functional implant with great application potential in bone tissue regeneration and repair.}, } @article {pmid37139491, year = {2023}, author = {Bari, AK and Belalekar, TS and Poojary, A and Rohra, S}, title = {Combination drug strategies for biofilm eradication using synthetic and natural agents in KAPE pathogens.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1155699}, pmid = {37139491}, issn = {2235-2988}, mesh = {*Biofilms ; *Anti-Bacterial Agents/pharmacology ; Bacteria ; Tobramycin/pharmacology ; Chlorhexidine ; }, abstract = {Antibiotic resistance is a global threat caused by factors such as overuse of antibiotics, lack of awareness, development of biofilms etc. World Health Organization released a list of global priority pathogens which consisted of 12 species of bacteria categorized as expressing critical, high and medium resistance. Several Gram-negative and Gram-positive species are known to cause wide varieties of infections and have become multidrug or extremely drug resistant. Pathogens causing infections associated with invasive medical devices are biofilm producers and hence their treatment becomes difficult due to a structurally stable matrix which prevents antibiotics from penetrating the biofilm and thereby showing its effects. Factors contributing to tolerance are inhibition of penetration, restricted growth and activation of biofilm genes. Combination drug therapies has also shown potential to eradicate biofilm infections. A combination of inhaled Fosfomycin/tobramycin antibiotic strategy has been effective against Gram-negative as well as Gram positive organisms. Along with antibiotics, use of natural or synthetic adjuvants shows promising effects to treat biofilm infections. Fluroquinolone activity on biofilms is disrupted by low oxygen tension in the matrix, a strategy known as hyperbaric oxygen treatment that can enhance efficacy of antibiotics if well optimized. Adjuvants such as Ethylenediaminetetraacetic acid (EDTA), Sodium Dodecyl Sulphate (SDS) and chlorhexidine act by killing non-growing microbial cells aggregated on the inner layer of the biofilm. This review aims to list down current combination therapies used against Gram-negative and Gram-positive biofilm forming pathogens and brief about comparison of combination drugs and their efficacies.}, } @article {pmid37138664, year = {2023}, author = {Sun, Y and Chen, H and Xu, M and He, L and Mao, H and Yang, S and Qiao, X and Yang, D}, title = {Exopolysaccharides metabolism and cariogenesis of Streptococcus mutans biofilm regulated by antisense vicK RNA.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2204250}, pmid = {37138664}, issn = {2000-2297}, abstract = {BACKGROUND: Streptococcus mutans (S. mutans) is a pivotal cariogenic pathogen contributing to its multiple virulence factors, one of which is synthesizing exopolysaccharides (EPS). VicK, a sensor histidine kinase, plays a major role in regulating genes associated with EPS synthesis and adhesion. Here we first identified an antisense vicK RNA (ASvicK) bound with vicK into double-stranded RNA (dsRNA).

OBJECTIVE: This study aims to investigate the effect and mechanism of ASvicK in the EPS metabolism and cariogenesis of S. mutans.

METHODS: The phenotypes of biofilm were detected by scanning electron microscopy (SEM), gas chromatography-mass spectrometery (GC-MS) , gel permeation chromatography (GPC) , transcriptome analysis and Western blot. Co-immunoprecipitation (Co-ip) assay and enzyme activity experiment were adopted to investigate the mechanism of ASvicK regulation. Caries animal models were developed to study the relationship between ASvicK and cariogenicity of S. mutans.

RESULTS: Overexpression of ASvicK can inhibit the growth of biofilm, reduce the production of EPS and alter genes and protein related to EPS metabolism. ASvicK can adsorb RNase III to regulate vicK and affect the cariogenicity of S. mutans.

CONCLUSIONS: ASvicK regulates vicK at the transcriptional and post-transcriptional levels, effectively inhibits EPS synthesis and biofilm formation and reduces its cariogenicity in vivo.}, } @article {pmid37138622, year = {2023}, author = {Zhou, Y and Jiang, D and Yao, X and Luo, Y and Yang, Z and Ren, M and Zhang, G and Yu, Y and Lu, A and Wang, Y}, title = {Pan-genome wide association study of Glaesserella parasuis highlights genes associated with virulence and biofilm formation.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1160433}, pmid = {37138622}, issn = {1664-302X}, abstract = {Glaesserella parasuis is a gram-negative bacterium that causes fibrotic polyserositis and arthritis in pig, significantly affecting the pig industry. The pan-genome of G. parasuis is open. As the number of genes increases, the core and accessory genomes may show more pronounced differences. The genes associated with virulence and biofilm formation are also still unclear due to the diversity of G. parasuis. Therefore, we have applied a pan-genome-wide association study (Pan-GWAS) to 121 strains G. parasuis. Our analysis revealed that the core genome consists of 1,133 genes associated with the cytoskeleton, virulence, and basic biological processes. The accessory genome is highly variable and is a major cause of genetic diversity in G. parasuis. Furthermore, two biologically important traits (virulence, biofilm formation) of G. parasuis were studied via pan-GWAS to search for genes associated with the traits. A total of 142 genes were associated with strong virulence traits. By affecting metabolic pathways and capturing the host nutrients, these genes are involved in signal pathways and virulence factors, which are beneficial for bacterial survival and biofilm formation. This research lays the foundation for further studies on virulence and biofilm formation and provides potential new drug and vaccine targets against G. parasuis.}, } @article {pmid37138171, year = {2023}, author = {Gao, M and Xu, B and Huang, Y and Cao, J and Yang, L and Liu, X and Djumaev, A and Wu, D and Shoxiddinova, M and Cai, X and Tojiyev, B and Zheng, H and Li, X and Normurodova, K and Liu, H and Li, R}, title = {Nano-enabled Quenching of Bacterial Communications for the Prevention of Biofilm Formation.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {}, number = {}, pages = {e202305485}, doi = {10.1002/anie.202305485}, pmid = {37138171}, issn = {1521-3773}, support = {2020YFA0710700//National Key R&D Program of China/ ; 21976126//National Natural Science Foundation of China/ ; BK20211545//Natural Science Foundation of Jiangsu Province/ ; }, abstract = {Biofilm formation is a major threat to industry, the environment and human health. While killing of embedded microbes in biofilms may inevitably lead to the evolution of antimicrobial resistance (AMR), catalytic quenching of bacterial communications by lactonase is a promising antifouling approach. Given the shortcomings of protein enzymes, it is attractive to engineer synthetic materials to mimic the activity of lactonase. Herein, an efficient lactonase-like Zn-Nx -C nanomaterial was synthesized by tuning the coordination environment around zinc atoms to mimic the active domain of lactonase for catalytical interception of bacterial communications in biofilm formation. The Zn-Nx -C material could selectively catalyze 77.5 % hydrolysis of N-acylated-L-homoserine lactone (AHL), a critical bacterial quorum sensing (QS) signal in biofilm construction. Consequently, AHL degradation downregulated the expression of QS-related genes in antibiotic resistant bacteria and significantly prevented biofilm formation. As a proof of concept, Zn-Nx -C-coated iron plates prevented 80.3 % biofouling after a month exposure in river. Overall, our study provides a nano-enabled contactless antifouling insight to avoid AMR evolution by engineering nanomaterials for mimicking the key bacterial enzymes (e.g., lactonase) functioning in biofilm construction.}, } @article {pmid37134292, year = {2023}, author = {Strange, M}, title = {Biofilm Management Technology: Air Polishing a Safe, Effective Modality.}, journal = {Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995)}, volume = {44}, number = {5}, pages = {276-277}, pmid = {37134292}, issn = {2158-1797}, mesh = {Humans ; *Dental Caries ; Dental Polishing ; *Tooth ; Biofilms ; *Mouth Diseases ; }, abstract = {Biofilms are complex communities of microorganisms that adhere to each other. They thrive and proliferate in all kinds of natural aqueous environments. Dentistry regards biofilms as an etiological factor for a range of oral diseases, including dental caries, periodontal disease, and implant-associated infections.1 This assertion is because the oral cavity and polymicrobial biofilm are home to numerous microbial species, including healthy microorganisms and those with pathogenic potential. Due to their stickiness and ability to multiply on surfaces, biofilms are highly resistant to both the host's defense system and traditional antimicrobials. As a result, the study and understanding of biofilm and resulting management technology have come a long way with novel methods to combat the formation and accumulation of bacterial biofilms on teeth and oral surfaces. Over the years, significant advancements have greatly improved the prevention and treatment of oral diseases caused by biofilms.}, } @article {pmid37133975, year = {2023}, author = {Duarte, PM and Felix, E and Santos, VR and Figueiredo, LC and da Silva, HDP and Mendes, JAV and Feres, M and Miranda, TS}, title = {Patients with type 2 diabetes and severe periodontitis harbor a less pathogenic subgingival biofilm than normoglycemic individuals with severe periodontitis.}, journal = {Journal of periodontology}, volume = {}, number = {}, pages = {}, doi = {10.1002/JPER.22-0657}, pmid = {37133975}, issn = {1943-3670}, support = {2007/55291-9//São Paulo State Research Foundation/ ; 2008/09687-0//São Paulo State Research Foundation/ ; 2008/11419-4//São Paulo State Research Foundation/ ; 2009/17677-8//São Paulo State Research Foundation/ ; 2011/14872-4//São Paulo State Research Foundation/ ; 2013/23743-9//São Paulo State Research Foundation/ ; 2013/10354-4//São Paulo State Research Foundation/ ; 2013/01072-5//São Paulo State Research Foundation/ ; }, abstract = {BACKGROUND: Whether, and to what extent, diabetes mellitus (DM) can affect the subgingival biofilm composition remains controversial. Thus, the aim of this study was to compare the composition of the subgingival microbiota of non-diabetic and type 2 diabetic patients with periodontitis using 40 "biomarker bacterial species."

METHODS: Biofilm samples of shallow (probing depth [PD] and clinical attachment level [CAL] ≤3 mm without bleeding) and deep sites (PD and CAL ≥5 mm with bleeding) of patients with or without type 2 DM were evaluated for levels/proportions of 40 bacterial species by checkerboard DNA-DNA hybridization.

RESULTS: A total of 828 subgingival biofilm samples from 207 patients with periodontitis (118 normoglycemic and 89 with type 2 DM) were analyzed. The levels of most of the bacterial species evaluated were reduced in the diabetic compared with the normoglycemic group, both in shallow and in deep sites. The shallow and deep sites of patients with type 2 DM presented higher proportions of Actinomyces species, purple and green complexes, and lower proportions of red complex pathogens than those of normoglycemic patients (P < 0.05).

CONCLUSIONS: Patients with type 2 DM have a less dysbiotic subgingival microbial profile than normoglycemic patients, including lower levels/proportions of pathogens and higher levels/proportions of host-compatible species. Thus, type 2 diabetic patients seem to require less remarkable changes in biofilm composition than non-diabetic patients to develop the same pattern of periodontitis.}, } @article {pmid37133439, year = {2023}, author = {Tran, NN and Morrisette, T and Jorgensen, SCJ and Orench-Benvenutti, JM and Kebriaei, R}, title = {Current therapies and challenges for the treatment of Staphylococcus aureus biofilm-related infections.}, journal = {Pharmacotherapy}, volume = {}, number = {}, pages = {}, doi = {10.1002/phar.2806}, pmid = {37133439}, issn = {1875-9114}, support = {//OSU College of Pharmacy, Division of Outcomes and Translational Sciences/ ; }, abstract = {Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and contributes to significant increase in morbidity and mortality especially when associated with medical devices and in biofilm form. Biofilm structure provides a pathway for the enrichment of resistant and persistent phenotypes of S. aureus leading to relapse and recurrence of infection. Minimal diffusion of antibiotics inside biofilm structure leads to heterogeneity and distinct physiological activity. Additionally, horizontal gene transfer between cells in proximity adds to the challenges associated with eradication of biofilms. This narrative review focuses on biofilm-associated infections caused by S. aureus, the impact of environmental conditions on biofilm formation, interactions inside biofilm communities, and the clinical challenges that they present. Conclusively, potential solutions, novel treatment strategies, combination therapies, and reported alternatives are discussed.}, } @article {pmid37132134, year = {2023}, author = {Shakib, P and Saki, R and Marzban, A and Goudarzi, G and Ghotekar, S and Cheraghipour, K and Zolfaghari, MR}, title = {Antibacterial Effects of Nanocomposites on Efflux Pump Expression and Biofilm Production in Pseudomonas aeruginosa: A Systematic Review.}, journal = {Current pharmaceutical biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.2174/1389201024666230428121122}, pmid = {37132134}, issn = {1873-4316}, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic gram-negative pathogen with multiple mechanisms of resistance to antibiotics. This systematic review aimed to study the antibacterial effects of nanocomposites on efflux pump expression and biofilm production in P. aeruginosa.

METHODS: The search was conducted from January 1, 2000, to May 30, 2022, using terms such as (P. aeruginosa) AND (biofilm) AND (antibiofilm activity) AND (anti-Efflux Pump Expression activity) AND (nanoparticles) AND (Efflux Pump Expression) AND (Solid Lipid NPS) AND (Nano Lipid Carriers). Many databases are included in the collection, including ScienceDirect, PubMed, Scopus, Ovid, and Cochrane.

RESULTS: A list of selected articles was retrieved by using the relevant keywords. A total of 323 published papers were selected and imported into the Endnote library (version X9). Following the removal of duplicates, 240 were selected for further processing. Based on the titles and abstracts of the articles, 54 irrelevant studies were excluded. Among the remaining 186 articles, 54 were included in the analysis because their full texts were accessible. Ultimately, 74 studies were selected based on inclusion/exclusion criteria.

CONCLUSION: Recent studies regarding the impact of NPs on drug resistance in P. aeruginosa found that various nanostructures were developed with different antimicrobial properties. The results of our study suggest that NPs may be a feasible alternative for combating microbial resistance in P. aeruginosa by blocking flux pumps and inhibiting biofilm formation.}, } @article {pmid37132080, year = {2023}, author = {Irwin, S and Wang, T and Bolam, SM and Alvares, S and Swift, S and Cornish, J and Williams, DL and Ashton, NN and Matthews, BG}, title = {Rat model of recalcitrant prosthetic joint infection using biofilm inocula.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {}, number = {}, pages = {}, doi = {10.1002/jor.25587}, pmid = {37132080}, issn = {1554-527X}, support = {//MedTech CoRE: PhD Scholarship/ ; //Auckland Medical Research Foundation/ ; //Royal Society Te Aparangi/ ; //Auckland Academic Health Alliance/ ; }, abstract = {Prosthetic joint infection (PJI) is a rare but devastating complication of joint arthroplasty. Biofilm formation around the prosthesis confers tolerance to antibiotics so that treatment is challenging. Most animal models of PJI use planktonic bacteria to establish the infection which fails to reproduce the pathology of chronic infection. We aimed to establish a rat model of Staphylococcus aureus PJI in male Sprague-Dawley rats using biofilm inocula and demonstrate its tolerance to frontline antibiotics. Pilot studies indicated that infection could be introduced to the knee joint by a biofilm-coated pin but that handling the prosthetic without disturbing the biofilm was difficult. We, therefore, developed a pin with a slotted end and used a miniature-biofilm reactor to develop mature biofilm in this niche. These biofilm-laden pins consistently produced infection of the bone and joint space. Treatment with high dose cefazolin, 250 mg/kg, starting the day of surgery reduced or cleared pin-adherent bioburden within 7 days, however when escalation from 25 to 250 mg/kg cefazolin treatment was delayed for 48 h, rats were unable to clear the infection. To track infections, we used bioluminescent bacteria, however, the bioluminescent signal did not accurately track the degree of infection in the bone and joint space as the signal did not penetrate the bone. In conclusion, we demonstrate that using a custom prosthetic pin, we can generate biofilm in a specific niche using a novel bioreactor setup and initiate a rat PJI that rapidly develops tolerance to supra-clinical doses of cefazolin.}, } @article {pmid37129770, year = {2023}, author = {Young, ES and Butler, JD and Molesworth-Kenyon, SJ and Kenyon, WJ}, title = {Biofilm-Mediated Fragmentation and Degradation of Microcrystalline Cellulose by Cellulomonas flavigena KU (ATCC 53703).}, journal = {Current microbiology}, volume = {80}, number = {6}, pages = {200}, pmid = {37129770}, issn = {1432-0991}, support = {FY23 SRAP 10046729//University of West Georgia/ ; }, mesh = {*Cellulose/metabolism ; *Glucans ; Biofilms ; }, abstract = {Cellulomonas flavigena KU (ATCC 53703) produces an extracellular matrix involved in the degradation of microcrystalline cellulose. This extracellular material is primarily composed of the gel-forming, β-1,3-glucan known as curdlan and associated, cellulose-degrading enzymes. In this study, the effects of various forms of nutrient limitation on cellulose attachment, cellular aggregation, curdlan production, and biofilm formation were investigated throughout a 7-day incubation period by using phase-contrast microscopy. Compared to cultures grown in non-limiting media, nitrogen-limitation promoted early attachment of C. flavigena KU cells to the cellulose surface, and cellulose attachment was congruent with cellular aggregation and curdlan production. Over the course of the experiment, microcolonies of attached cells grew into curdlan-producing biofilms on the cellulose. By contrast, bacterial cells grown on cellulose in non-limiting media remained unattached and unaggregated throughout most of the incubation period. By 7 days of incubation, bacterial aggregation was ninefold greater in N-limited cultures compared to nutritionally complete cultures. In a similar way, phosphorus- and vitamin-limitation (i.e., yeast extract-limitation) also resulted in early cellulose attachment and biofilm formation. Furthermore, nutrient limitation promoted more rapid and efficient fragmentation and degradation of cellulose, with cellulose fragments in low-N media averaging half the size of those in high-N media after 7 days. Two modes of cellulose degradation are proposed for C. flavigena KU, a "planktonic mode" and a "biofilm mode". Similar observations have been reported for other curdlan-producing cellulomonads, and these differing cellulose degradation strategies may ultimately prove to reflect sequential stages of a multifaceted biofilm cycle important in the bioconversion of this abundant and renewable natural resource.}, } @article {pmid37129526, year = {2023}, author = {Vasicek, EM and Gunn, JS}, title = {Invasive Non-Typhoidal Salmonella Lineage Biofilm Formation and Gallbladder Colonization Vary But Do Not Correlate Directly with Known Biofilm-Related Mutations.}, journal = {Infection and immunity}, volume = {91}, number = {5}, pages = {e0013523}, pmid = {37129526}, issn = {1098-5522}, support = {R21 AI153752/AI/NIAID NIH HHS/United States ; R21 AI156328/AI/NIAID NIH HHS/United States ; R01 AI116917/AI/NIAID NIH HHS/United States ; }, mesh = {Mice ; Animals ; Humans ; *Gallbladder/microbiology ; Salmonella ; Biofilms ; *Typhoid Fever ; Cellulose ; Mutation ; }, abstract = {Non-typhoidal Salmonella (NTS) serovars have a broad host range and cause gastroenteritis in humans. However, invasive NTS (iNTS) bloodstream infections have increased in the last decade, causing 60,000 deaths annually. Human-specific typhoidal Salmonella colonizes and forms biofilms on gallstones, resulting in chronic, asymptomatic infection. iNTS lineages are undergoing genomic reduction and may have adapted to person-to-person transmission via mutations in virulence, bile resistance, and biofilm formation. As such, we sought to determine the capacity of iNTS lineages for biofilm formation and the development of chronic infections in the gallbladder in our mouse model. Of the lineages tested (L1, L2, L3 and UK), only L2 and UK were defective for the rough, dry and red (RDAR) morphotype, correlating with the known bcsG (cellulose) mutation but not with csgD (curli) gene mutations. Biofilm-forming ability was assessed in vitro, which revealed a biofilm formation hierarchy of L3 > ST19 > UK > L1 = L2, which did not correlate directly with either the bcsG or the csgD mutation. By confocal microscopy, biofilms of L2 and UK had significantly less curli and cellulose, while L1 biofilms had significantly lower cellulose. All iNTS strains were able to colonize the mouse gallbladder, liver, and spleen in a similar manner, while L3 had a significantly higher bacterial load in the gallbladder and increased lethality. While there was iNTS lineage variability in biofilm formation, gallbladder colonization, and virulence in a chronic mouse model, all tested lineages were capable of colonization despite possessing biofilm-related mutations. Thus, iNTS strains may be unrecognized chronic pathogens in endemic settings.}, } @article {pmid37129321, year = {2023}, author = {Bernardi, S and Qorri, E and Botticelli, G and Scarano, A and Marzo, G and Gatto, R and Greco Lucchina, A and Mortellaro, C and Lupi, E and Rastelli, C and Falisi, G}, title = {Use of electrical field for biofilm implant removal.}, journal = {European review for medical and pharmacological sciences}, volume = {27}, number = {3 Suppl}, pages = {114-121}, doi = {10.26355/eurrev_202304_31328}, pmid = {37129321}, issn = {2284-0729}, mesh = {Humans ; *Peri-Implantitis ; *Mucositis ; Device Removal ; Biofilms ; Microscopy, Electron, Scanning ; *Dental Implants ; Surface Properties ; }, abstract = {OBJECTIVE: New methods for biofilm removal are being investigated. A recent new one involves the use of the electric field for biofilm removal. In particular, electrolytic cleaning works on the adhesion forces of the biofilm on the surfaces, with few studies showing promising results in decontamination and implant re-integration in the bone. This study aims at assessing the effect of a new decontamination device that implies the electric field for implant-biofilm removal.

MATERIALS AND METHODS: Three implants affected by peri-implantitis were selected for the study. After the treatment, the implants were observed by the Scanning Electron Microscopy.

RESULTS: All three samples showed no microbial biofilm in the application area, while the rest of the surface observed was covered with microbial biofilm, with an intensely thickened bacterial population.

CONCLUSIONS: Peri-mucositis and peri-implantitis prevention and early treatments are essential for implant maintenance, thus saving the surrounding hard and soft tissues. The technological innovation is providing electrolytic devices which act not only on the microbial population but on the biofilm adhesion to the implant surface, with promising results for a new and valid therapeutic option.}, } @article {pmid37127198, year = {2023}, author = {Han, Y and Yang, P and Feng, Y and Wang, N and Yuan, X and An, J and Liu, J and Li, N and He, W}, title = {Liquid-gas phase transition enables microbial electrolysis and H2-based membrane biofilm hybrid system to degrade organic pollution and achieve effective hydrogenotrophic denitrification of groundwater.}, journal = {Chemosphere}, volume = {331}, number = {}, pages = {138819}, doi = {10.1016/j.chemosphere.2023.138819}, pmid = {37127198}, issn = {1879-1298}, mesh = {*Denitrification ; Bioreactors ; Nitrates/metabolism ; Hydrogen ; *Groundwater ; Biofilms ; Electrolysis ; }, abstract = {Electron-donor Lacking was the limiting factor for the denitrification of oligotrophic groundwater and hydrogenotrophic denitrification provided an efficient approach without secondary pollution. In this study, a hybrid system with microbial electrolysis cell (MEC) assisted hydrogen-based membrane biofilm reactor (MBfR) was established for advanced groundwater denitrification. The liquid-gas phase transition prevented the potential pollution from organic wastes in MEC to groundwater, while the bubble-free diffusion of MBfR promoted hydrogen utilization efficiency. The negative-pressure extraction from MEC and the positive pressure for gas supply into MBfR increased the hydrogen proportion and current density of MEC, and improved the kinetic constant K of the denitrification reaction in MBfR. With actual groundwater, the MEC-MBfR hybrid system achieved a nitrate reduction of 97.8% with an effluent NO3[-]-N of 2.2 ± 1.0 mg L[-1]. The hydrogenotrophic denitrifiers of Thauera, Pannonibacter, and Azonexus, dominated the denitrification biofilm on the membrane and elastic filler in MBfR.}, } @article {pmid37127169, year = {2023}, author = {Zhang, X and Zuo, S and Li, S and Shang, Y and Du, Q and Wang, H and Guo, W and Ngo, HH}, title = {Responses of biofilm communities in a hybrid moving bed biofilm reactor-membrane bioreactor system to sulfadiazine antibiotic exposure.}, journal = {Bioresource technology}, volume = {382}, number = {}, pages = {129126}, doi = {10.1016/j.biortech.2023.129126}, pmid = {37127169}, issn = {1873-2976}, mesh = {*Wastewater ; *Sulfadiazine ; Anti-Bacterial Agents/pharmacology ; Nitrification ; Biofilms ; Bioreactors/microbiology ; Bacteria ; Nitrogen/chemistry ; Carbon/chemistry ; Denitrification ; }, abstract = {Antibiotics in wastewater can affect the structures and functions of bacterial communities, subsequently influencing how well a biological process performs. Therefore, the characteristics of bacterial community were investigated in a hybrid moving bed biofilm reactor-membrane bioreactor system when treating domestic wastewater containing sulfadiazine (SDZ). Results indicated total nitrogen removal reduced by 10.2%, 9.1%, 2.7% and 2.9%, respectively, with increasing carbon to nitrogen (C/N) ratios (2.5, 4, 6 and 9) when SDZ was present (0.5 mg/L). The microbial communities' analysis revealed that the abundance of nitrogen removal-related bacteria increased with C/N. Specifically, the abundance of ammonia-oxidizing bacteria (0.46%-0.90%) was low, and the nitrite-oxidizing bacteria (2.16%-7.13%) and denitrifying bacteria showed a significant increase (Hyphomicrobium: 0.57%-3.54%) when C/N ratio increased. The abundance of denitrifying bacterial declined by 4.82-8.56% at different C/N ratios, while nitrifying bacterial rose by 0.70-5.67%. Interestingly, the denitrifying bacteria Enterobacter, Sphingomonas and Gemmatimonas acted as mutualistic bacteria that stabilized denitrification.}, } @article {pmid37125396, year = {2023}, author = {Díaz-Navarro, M and Irigoyen Von-Sierakowski, Á and Palomo, M and Escribano, P and Guinea, J and Burillo, A and Galar, A and Muñoz, P and Guembe, M}, title = {In vitro study to assess modulation of Candida biofilm by Escherichia coli from vaginal strains.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100116}, pmid = {37125396}, issn = {2590-2075}, abstract = {BACKGROUND: Vulvovaginal candidiasis (VVC) is caused by biofilm formation and epithelial invasion. In addition, Escherichia coli (EC) can establish a vaginal intracellular reservoir modulating Candida spp. biofilm production. We aimed to analyze the behavior of Candida albicans (CA) and EC biofilm both in single cultures and in co-cultures.

METHODS: We prospectively collected CA and EC isolates from vaginal swabs over 6 months. We selected positive cultures with both CA and EC (cases) and a comparator group with either CA or EC (controls). We analyzed overall biomass production and metabolic activity in single cultures and in co-cultures based on staining assays, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) to assess biofilm occupation. We also analyzed clinical manifestations.

RESULTS: We cultured 455 samples, 16 (3.5%) of which had CA and EC (cases); only CA or EC (controls) was detected, respectively, in 72 (15.8%) and 98 (21.5%). Biomass production and metabolic activity were significantly more pronounced in co-cultures in both groups. CLSM and SEM, on the other hand, showed the biofilm of each species to be significantly reduced when they were cultured together, with higher values in CA (percentage biofilm reduction: CA, 95.8% vs. EC, 36.2%, p < 0.001). There were no clinically significant differences between co-infected patients and patients infected only by C. albicans.

CONCLUSION: Ours is the first study assessing co-cultures of CA and EC in a large collection of samples. We observed that coinfection of CA and EC was unusual (3.5%) and promoted high biomass, whereas microscopy enabled us to detect a reduction in biofilm production when microorganisms were co-cultured. No differences in symptoms were observed.}, } @article {pmid37125394, year = {2023}, author = {Lamret, F and Lemaire, A and Lagoutte, M and Varin-Simon, J and Abraham, L and Colin, M and Braux, J and Velard, F and Gangloff, SC and Reffuveille, F}, title = {Approaching prosthesis infection environment: Development of an innovative in vitro Staphylococcus aureus biofilm model.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100120}, pmid = {37125394}, issn = {2590-2075}, abstract = {The major role and implication of bacterial biofilms in the case of bone and prosthesis infections have been highlighted and often linked to implant colonization. Management strategies of these difficult-to-treat infections consist in surgeries and antibiotic treatment, but the rate of relapse remains high, especially if Staphylococcus aureus, a high-virulent pathogen, is involved. Therapeutic approaches are not adapted to the specific features of biofilm in bone context whereas infectious environment is known to importantly influence biofilm structure. In the present study, we aim to characterize S. aureus SH1000 (methicillin-sensitive strain, MSSA) and USA300 (methicillin-resistant strain, MRSA) biofilm on different surfaces mimicking the periprosthetic environment. As expected, protein adsorption on titanium enhanced the number of adherent bacteria for both strains. On bone explant, USA300 adhered more than SH1000. The simultaneous presence of two different surfaces was also found to change the bacterial behaviour. Thus, proteins adsorption on titanium and bone samples (from bank or directly recovered after an arthroplasty) were found to be key parameters that influence S. aureus biofilm formation: adhesion, matrix production and biofilm-related gene regulation. These results highlighted the need for new biofilm models, more relevant with the infectious environment by using adapted culture medium and presence of surfaces that are representative of in situ conditions to better evaluate therapeutic strategies against biofilm.}, } @article {pmid37125177, year = {2023}, author = {Sadiq, FA and De Reu, K and Burmølle, M and Maes, S and Heyndrickx, M}, title = {Synergistic interactions in multispecies biofilm combinations of bacterial isolates recovered from diverse food processing industries.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1159434}, pmid = {37125177}, issn = {1664-302X}, abstract = {Most biofilms within the food industry are formed by multiple bacterial species which co-exist on surfaces as a result of interspecies interactions. These ecological interactions often make these communities tolerant against antimicrobials. Our previous work led to the identification of a large number (327) of highly diverse bacterial species on food contact surfaces of the dairy, meat, and egg industries after routine cleaning and disinfection (C&D) regimes. In the current study, biofilm-forming ability of 92 bacterial strains belonging to 26 genera and 42 species was assessed and synergistic interactions in biofilm formation were investigated by coculturing species in all possible four-species combinations. Out of the total 455 four-species biofilm combinations, greater biofilm mass production, compared to the sum of biofilm masses of individual species in monoculture, was observed in 34 combinations. Around half of the combinations showed synergy in biofilm mass > 1.5-fold and most of the combinations belonged to dairy strains. The highest synergy (3.13-fold) was shown by a combination of dairy strains comprising Stenotrophomonas rhizophila, Bacillus licheniformis, Microbacterium lacticum, and Calidifontibacter indicus. The observed synergy in mixed biofilms turned out to be strain-specific rather than species-dependent. All biofilm combinations showing remarkable synergy appeared to have certain common species in all combinations which shows there are keystone industry-specific bacterial species which stimulate synergy or antagonism and this may have implication for biofilm control in the concerned food industries.}, } @article {pmid37123502, year = {2023}, author = {Dao, A and O'Donohue, AK and Vasiljevski, ER and Bobyn, JD and Little, DG and Schindeler, A}, title = {Murine models of orthopedic infection featuring Staphylococcus aureus biofilm.}, journal = {Journal of bone and joint infection}, volume = {8}, number = {2}, pages = {81-89}, pmid = {37123502}, issn = {2206-3552}, abstract = {Introduction: Osteomyelitis remains a major clinical challenge. Many published rodent fracture infection models are costly compared with murine models for rapid screening and proof-of-concept studies. We aimed to develop a dependable and cost-effective murine bone infection model that mimics bacterial bone infections associated with biofilm and metal implants. Methods: Tibial drilled hole (TDH) and needle insertion surgery (NIS) infection models were compared in C57BL/6 mice (female, N = 150). Metal pins were inserted selectively into the medullary canal adjacent to the defect sites on the metaphysis. Free Staphylococcus aureus (ATCC 12600) or biofilm suspension (ATCC 25923) was locally inoculated. Animals were monitored for physiological or radiographic evidence of infection without prophylactic antibiotics for up to 14 d. At the end point, bone swabs, soft-tissue biopsies, and metal pins were taken for cultures. X-ray and micro-CT scans were performed along with histology analysis. Results: TDH and NIS both achieved a 100 % infection rate in tibiae when a metal implant was present with injection of free bacteria. In the absence of an implant, inoculation with a bacterial biofilm still induced a 40 %-50 % infection rate. In contrast, freely suspended bacteria and no implant consistently showed lower or negligible infection rates. Micro-CT analysis confirmed that biofilm infection caused local bone loss even without a metal implant as a nidus. Although a metal surface permissive for biofilm formation is impermeable to create progressive bone infections in animal models, the metal implant can be dismissed if a bacterial biofilm is used. Conclusion: These models have a high potential utility for modeling surgery-related osteomyelitis, with NIS being simpler to perform than TDH.}, } @article {pmid37123152, year = {2022}, author = {Kareem Musafer, H and Nabeeh Jaafar, F and Ahmed Al-Bayati, M}, title = {Association of Biofilm Inducer with bla VIM, bla IMP, and bla NDM in Pseudomonas aeruginosa Isolates.}, journal = {Archives of Razi Institute}, volume = {77}, number = {5}, pages = {1723-1728}, pmid = {37123152}, issn = {2008-9872}, mesh = {*Bacterial Proteins/genetics ; beta-Lactamases/genetics ; Carbapenems ; Imipenem ; Meropenem ; *Pseudomonas aeruginosa/drug effects/genetics ; Biofilms ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is a ubiquitous opportunistic organism that is hard to treat. This study aimed to investigate the association of bla VIM, bla IMP, and bla NDM prevalence with Cyclic di-GMP (c-di-GMP) in P. aeruginosa. To this end, 27 clinical isolates of P. aeruginosa were obtained from different hospitals in Baghdad, Iraq. The phenotypic detection of carbapenem and biofilm assays was performed by the M63 minimal medium, supplemented with glucose, magnesium sulfate. The polymerase chain reaction was utilized to detect carbapenem genes. The results showed that the isolates were highly resistant to Imipenem (37%) and Meropenem (63%). Imipenem (37%) and Meropenem (63%) demonstrated a moderate sensitivity against P. aeruginosa. The P. aeruginosa No.5 showed high resistance to carbapenem by bla VIM [+], bla IMP [+], and bla NDM [+], followed by a robust biofilm confirmed with c-di-GMP levels and the twitching motility ability. Upon these findings, the use of antibiotics should be restricted to severe bacterial infections to avoid the rapid emergence of new resistant isolates, which leads to the hard treatment of infection with P. aeruginosa. It is highly recommended that these findings be notified for infectious control. Future studies can investigate the link between transferable resistant genes and c-di-GMP values.}, } @article {pmid37122169, year = {2023}, author = {Aguiar, ALR and Silva, BND and Fiallos, NM and Pereira, LMG and Silva, ML and Souza, PFSM and Portela, FVM and Sidrim, JJC and Rocha, MFG and Castelo-Branco, DSCM and Cordeiro, RA}, title = {Promethazine inhibits efflux, enhances antifungal susceptibility and disrupts biofilm structure and functioning in Trichosporon.}, journal = {Biofouling}, volume = {39}, number = {2}, pages = {218-230}, doi = {10.1080/08927014.2023.2202315}, pmid = {37122169}, issn = {1029-2454}, mesh = {Humans ; *Antifungal Agents/pharmacology/metabolism ; *Trichosporon ; Promethazine/pharmacology/metabolism ; Biofilms ; Plankton ; Microbial Sensitivity Tests ; }, abstract = {Trichosporon spp. are emerging opportunistic fungi associated with invasive infections, especially in patients with haematological malignancies. The present study investigated the in vitro inhibition of efflux pumps by promethazine (PMZ) as a strategy to control T. asahii and T. inkin. Planktonic cells were evaluated for antifungal susceptibility to PMZ, as well as inhibition of efflux. The effect of PMZ was also studied in Trichosporon biofilms. PMZ inhibited T. asahii and T. inkin planktonic cells at concentrations ranging from 32 to 256 μg[ ]ml[-1]. Subinhibitory concentrations of PMZ inhibited efflux activity in Trichosporon. Biofilms were completely eradicated by PMZ. PMZ potentiated the action of antifungals, affected the morphology, changed the amount of carbohydrates and proteins and reduced the amount of persister cells inside biofilms. The results showed indirect evidences of the occurrence of efflux pumps in Trichosporon and opens a perspective for the use of this target in the control of trichosporonosis.}, } @article {pmid37121323, year = {2023}, author = {Zheng, S and Lin, T and Chen, H and Zhang, X and Jiang, F}, title = {Characterization of young biofilm morphology, disinfection byproduct formation potential and toxicity of renewed water supply pipelines by phosphorus release from corroded pipes.}, journal = {The Science of the total environment}, volume = {884}, number = {}, pages = {163813}, doi = {10.1016/j.scitotenv.2023.163813}, pmid = {37121323}, issn = {1879-1026}, abstract = {The deterioration of drinking water quality due to corrosion of the water supply network has become inevitable and regular renewal of pipes has become a common means of doing so. Severely corroded pipes release certain nutrients (e.g., elemental phosphorus), however, little has been reported on the effect of old pipes on the young biofilm of new pipe sections and on ensuring water safety in the early stages of the water supply. The aim of our study was to model the effect of key phosphorus nutrients released from corroded old pipes on the morphological characteristics of young biofilms in new pipe sections, mediated disinfection byproducts (DBPs) production and their combined toxicity. Based on the experimental results, phosphorus showed significant differences in the morphological characteristics, spatial structure of extracellular polymers (EPS), functional abundance, disinfection byproduct formation potential (DBPsFP) and toxicity of young biofilms. Under residual chlorine (1.0 ± 0.2 mg/L) incubation, the functional abundance of young biofilm metabolism was dominant, particularly amino acid metabolism and carbohydrate metabolism. There is a dynamic balance between the trophic and shedding effects of phosphorus, where concentration changes affect young biofilm morphology and DBPFP. Relatively moderate phosphorus concentrations resulted in the highest density of PN/PS organic precursors in EPS and a clear advantage of DBPFP; relatively high phosphorus conditions had limited promotion of young biofilm, while membrane structure shedding was more pronounced, increasing young biofilm-mediated DBPs production. Nitrogen-containing disinfection byproducts (N-DBPs) in young biofilms had a clear toxicity advantage, with HANs and HNMs being key to controlling cytotoxicity and genotoxicity, respectively.}, } @article {pmid37121181, year = {2023}, author = {Kang, D and Zhang, L and Yang, S and Li, J and Peng, Y}, title = {Linking morphological features to anammox communities in a partial nitritation and anammox (PN/A) biofilm reactor.}, journal = {Journal of environmental management}, volume = {341}, number = {}, pages = {118038}, doi = {10.1016/j.jenvman.2023.118038}, pmid = {37121181}, issn = {1095-8630}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Bioreactors/microbiology ; Wastewater ; Sewage ; Bacteria/genetics ; Biofilms ; Nitrogen ; Oxidation-Reduction ; Denitrification ; }, abstract = {Partial nitritation/anammox (PN/A) has been recognized as a cost-efficient process for wastewater nitrogen removal. The addition of carriers could help achieve biomass retention and enhance the treatment efficiency by forming the dense biofilm. However, accurately determining the abundance of anammox bacteria (AnAOB) to evaluate the biofilm development still remains challenging in practice without access to specialized facilities and experimental skills. In this study, we explored the feasibility of utilizing the morphological features of anammox biofilm as an indication of the biofilm development progression, and its correlation with microbial communities was also revealed. The time-series biofilms from an integrated fixed-film activated sludge (IFAS) system with stable PN/A performance were sampled representing the different biofilm development stages. The biofilm morphological features including color and texture were respectively quantified by red (R) coordinate and Local binary pattern (LBP) descriptor via image processing. Hierarchy clustering analysis proved that the extracted morphological descriptors could well distinguish the different stages (colonization, succession, and maturation) of biofilm development. The microbial community dynamics of time-series anammox biofilms were investigated using the amplicon sequence variant (ASV) analysis. Candidatus Brocadia, as the typical AnAOB, dominated in the whole communities of 16.3%-20.0%, moreover, the biofilm development was found to be driven by distinct Brocadia species. Linear regression evidenced that the Brocadia abundance could be directly correlated to the value of R and LBP, and the total variation of microbial communities could be significantly explained by the morphological features via redundancy analysis. This study demonstrates a new way to monitor the biofilm development by extracting the visible features of anammox aggregates, which can help facilitate the automated control of anammox-based bioprocess.}, } @article {pmid37120944, year = {2023}, author = {Wang, S and Mirmiran, SD and Li, X and Li, X and Zhang, F and Duan, X and Gao, D and Chen, Y and Chen, H and Qian, P}, title = {Temperate phage influence virulence and biofilm-forming of Salmonella Typhimurium and enhance the ability to contaminate food product.}, journal = {International journal of food microbiology}, volume = {398}, number = {}, pages = {110223}, doi = {10.1016/j.ijfoodmicro.2023.110223}, pmid = {37120944}, issn = {1879-3460}, mesh = {Animals ; *Bacteriophages ; Salmonella typhimurium/genetics ; Virulence ; Phylogeny ; *Salmonella Phages/genetics ; Biofilms ; }, abstract = {Salmonella is a food-borne zoonotic pathogen that threatens food safety and public health security. Temperate phages can influence bacterial virulence and phenotype and play an important role in bacterial evolution. However, most studies on Salmonella temperate phages focus on prophage induced by bacteria, with few reports on Salmonella temperate phages isolated in the environment. Moreover, whether temperate phages drive bacterial virulence and biofilm formation in food and animal models remains unknown. In this study, Salmonella temperate phage vB_Sal_PHB48 was isolated from sewage. TEM and phylogenetic analysis indicated that phage PHB48 belongs to the Myoviridae family. Additionally, Salmonella Typhimurium integrating PHB48 was screened and designated as Sal013[+]. Whole genome sequencing revealed that the integration site was specific and we confirmed that the integration of PHB48 did not change the O-antigen and coding sequences of Sal013. Our in vitro and in vivo studies showed that the integration of PHB48 could significantly enhance the virulence and biofilm formation of S. Typhimurium. More importantly, the integration of PHB48 significantly improved the colonization and contamination ability of bacteria in food samples. In conclusion, we isolated Salmonella temperate phage directly from the environment and systematically clarified that PHB48 enhanced the virulence and biofilm-forming ability of Salmonella. In addition, we found that PHB48 increased the colonization and contamination ability of Salmonella in food samples. These results indicated that the highly pathogenic Salmonella induced by temperate phage was more harmful to food matrices and public health security. Our results could enhance the understanding of the evolutionary relationship between bacteriophages and bacteria, and raise public awareness of large-scale outbreaks resulting from Salmonella virulence enhancement in food industry.}, } @article {pmid37120455, year = {2023}, author = {Singh, I and Roshan, M and Vats, A and Behera, M and Gautam, D and Rajput, S and Rana, C and De, S}, title = {Evaluation of Virulence, Antimicrobial Resistance and Biofilm Forming Potential of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Bovine Suspected with Mastitis.}, journal = {Current microbiology}, volume = {80}, number = {6}, pages = {198}, pmid = {37120455}, issn = {1432-0991}, support = {EMR/2017/004602//Science and Engineering Research Board (SERB), Department of Science and Technology, Government of India/ ; DBT/2018/NDRI/1003//Department of Biotechnology, GOI, India/ ; }, mesh = {Female ; Animals ; Cattle ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; Virulence/genetics ; *Staphylococcal Infections/veterinary ; Drug Resistance, Bacterial ; Biofilms ; Virulence Factors/genetics ; *Mastitis, Bovine ; Microbial Sensitivity Tests ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that poses a significant threat in cases of chronic mastitis in dairy animals. The ability of MRSA to persist in the host is attributed to various virulence factors, genes encoding surface adhesins, and determinants of antibiotic resistance, which provide it a survival advantage. This investigation focused to determine the virulence factors, antimicrobial resistance (AMR) profile and biofilm production potential of 46 MRSA isolates from 300 bovine mastitis milk samples. The AMR profile revealed a high level of resistance, with 46 and 42 isolates resistant to cefoxitin and oxacillin, respectively, followed by 24 and 12 isolates resistant to lomefloxacin and erythromycin, respectively. Only 2 isolates resistant to tetracycline and none were resistant to chloramphenicol. The study also evaluated various virulence factors such as coa (n = 46), nuc (n = 35) hlg (n = 36), pvl (n = 14), tsst-1(n = 28) spa (n = 39) and enterotoxin genes sea (n = 12) and seg (n = 28) and identified antibiotic resistance determinants mecA and blaZ in 46 and 27 isolates, respectively. Intercellular adhesion genes icaA and icaD were present in 40 and 43 isolates, respectively and surface adhesion genes ebps, fnbpA, eno, sasG, cna, and bap were found in 43, 40, 38, 26, 21 and 1 isolates, respectively. Microtiter plate (MTP) assay revealed that 29 MRSA isolates were capable of producing biofilms, whereas 17 were not. Biofilms producing MRSA isolates possessed adhesion genes, virulence factors, toxin genes and AMR genes that may act synergistically towards a chronic disease progression, illness and severe damage to the udder, which generally last for several months and very challenging to cure.}, } @article {pmid37120241, year = {2023}, author = {He, X and Ding, H and Gao, Z and Zhang, X and Wu, R and Li, K}, title = {Variations in the motility and biofilm formation abilities of Escherichia coli O157:H7 during noodle processing.}, journal = {Food research international (Ottawa, Ont.)}, volume = {168}, number = {}, pages = {112670}, doi = {10.1016/j.foodres.2023.112670}, pmid = {37120241}, issn = {1873-7145}, mesh = {*Escherichia coli O157 ; Biofilms ; Food Handling ; Repressor Proteins/pharmacology ; RNA-Binding Proteins/pharmacology ; *Escherichia coli Proteins/metabolism ; }, abstract = {Motility and biofilm formation help to protect bacteria from host immune responses and facilitate tolerance of environmental stimuli to improve their adaptability. However, few reports have investigated the adaptability of bacteria that live in food substrates undergoing food processing-induced stress. In this study, variations in the surface morphology, bacterial count, motility, and biofilm formation abilities of Escherichia coli O157:H7 NCTC12900 were investigated during noodle processing, including the kneading, squeezing, resting, and sheeting phases. The results showed that bacterial surface morphology, count, and motility were impaired in the squeezing phase, whereas biofilm biomass continuously increased across all processing phases. Twenty-one genes and sRNAs were measured using RT-qPCR to reveal the mechanisms underlying these changes. Of these, the genes adrA, csrA, flgM, flhD, fliM, ydaM, and the sRNA McaS were significantly upregulated, whereas the genes fliA, fliG, and the sRNAs CsrC, DsrA, GcvB, and OxyS were evidently repressed. According to the correlation matrix results based on the reference gene adrA, we found that csrA, GcvB, McaS, and OxyS were the most relevant genes and sRNAs for biofilm formation and motility. For each of them, their overexpressions was found to inhibit bacterial motility and biofilm formation to varying degrees during noodle processing. Among these, 12900/pcsrA had the highest inhibitory potential against motility, yielding a minimum of 11.2 mm motility diameter in the resting phase. Furthermore, 12900/pOxyS showed the most significant inhibitory effect against biofilm formation, yielding a minimum biofilm formation value of 5% of that exhibited the wild strain in the sheeting phase. Therefore, we prospect to find an effective and feasible novel approach to weaken bacterial survival during food processing by regulating the genes or sRNAs related to motility and biofilm formation.}, } @article {pmid37116243, year = {2023}, author = {Daffinee, KE and O'Neill, ET and Bleick, CR and Williams, G and Antoci, V and Garcia, D and LaPlante, KL}, title = {Staphylococcal biofilm: penetration and bioavailability of vancomycin with or without rifampin.}, journal = {Diagnostic microbiology and infectious disease}, volume = {106}, number = {3}, pages = {115947}, doi = {10.1016/j.diagmicrobio.2023.115947}, pmid = {37116243}, issn = {1879-0070}, mesh = {Humans ; *Vancomycin ; Rifampin/pharmacology ; Biological Availability ; Staphylococcus epidermidis ; Anti-Bacterial Agents ; Biofilms ; Staphylococcus ; *Staphylococcal Infections/drug therapy ; Microbial Sensitivity Tests ; }, abstract = {We measured antibiotic penetration and bioavailability in staphylococcus biofilms using simulated humanized concentrations of fluorescent vancomycin plus or minus rifampin. Vancomycin percent recovery across biofilm layers was:upper = 46%, middle = 40%, and lower = 33%. Vancomycin plus rifampin was not significantly different (P = 0.65). Addition of rifampin did not improve vancomycin penetration across biofilm layers.}, } @article {pmid37115440, year = {2023}, author = {Tziourrou, P and Vakros, J and Karapanagioti, HK}, title = {Diffuse reflectance spectroscopy (DRS) and infrared (IR) measurements for studying biofilm formation on common plastic litter polymer (LDPE and PET) surfaces in three different laboratory aquatic environments.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {25}, pages = {67499-67512}, pmid = {37115440}, issn = {1614-7499}, support = {12671//HFRI/ ; }, mesh = {*Polyethylene/chemistry ; *Polyethylene Terephthalates ; Plastics ; Spectrum Analysis ; Biofilms ; Esters ; }, abstract = {Different species of microorganisms colonize the plastic surfaces and form biofilms depending on the aquatic environment. In the current investigation, characteristics of the plastic surface after exposure to three different aquatic environments based on visualization using scanning electron microscopy (SEM) and spectroscopic (diffuse reflectance (DR) and infrared (IR)) techniques were examined in laboratory bioreactors with time. For both materials, there were no differences observed in the ultraviolet (UV) region among the reactors and several peaks were observed with fluctuating intensities and without any trends. For light density polyethylene (LDPE), peaks indicating the presence of biofilm could be observed in the visible region for activated sludge bioreactor, and for polyethylene terephthalate (PET), freshwater algae biofilm was also visible. PET in freshwater bioreactor is the most densely populated sample both under the optical microscope and SEM. Based on the DR spectra, different visible peaks for LDPE and PET were observed but, in both cases, the visible region peaks (~ 450 and 670 nm) correspond to the peaks found in the water samples of the bioreactors. The difference on these surfaces could not be identified with IR but the fluctuations observed in the UV wavelength region were also detectable using indices obtained from the IR spectra such as keto, ester, and vinyl. For instance, the virgin PET sample shows higher values in all the indices than the virgin LDPE sample [(virgin LDPE: ester Index (I) = 0.051, keto I = 0.039, vinyl I = 0.067), (virgin PET: ester I = 3.5, keto I = 19, vinyl I = 0.18)]. This suggests that virgin PET surface is hydrophilic as expected. At the same time, for all the LDPE samples, all the indices demonstrated higher values (especially for R2) than the virgin LDPE. On the other hand, ester and keto indices for PET samples demonstrated lower values than virgin PET. In addition, DRS technique was able to identify the formation of the biofilm both on wet and dry samples. Both DRS and IR can describe changes in the hydrophobicity during the initial formation of biofilm but DRS can better describe the fluctuations of biofilm in the visible spectra region.}, } @article {pmid37115139, year = {2023}, author = {Uchoa-Junior, FA and Barata, TJE and Leão-Vasconcelos, LSNO and Ribeiro, EL and Tipple, AFV}, title = {Biofilm on and structural damage of rotary cutting instruments after 5 cycles of clinical use and processing.}, journal = {Journal of the American Dental Association (1939)}, volume = {154}, number = {6}, pages = {495-506}, doi = {10.1016/j.adaj.2023.03.005}, pmid = {37115139}, issn = {1943-4723}, mesh = {Humans ; Surface Properties ; *Diamond ; Microscopy, Electron, Scanning ; *Sterilization ; Dental Instruments ; Biofilms ; }, abstract = {BACKGROUND: Rotary cutting instruments (RCIs) are sterilized routinely. The authors aimed to analyze the structural integrity, presence of dirt, and microbial contamination of RCIs used in clinical practice after processing.

METHODS: Eighty-four RCIs (42 carbide burs, 42 diamond burs) were divided into baseline, control, and test groups. The RCIs were evaluated by means of scanning electron microscopy and microbiological analysis. Evaluation criteria included presence of structural damage, dirt, biofilm, and isolated cells and their phenotypic profile.

RESULTS: The carbide burs from all groups and diamond burs from the test groups had structural damage. Dirt was observed in the baseline and test groups. Three bacterial species were isolated from 4 RCIs (9.52%). An isolated cell was observed from 1 carbide bur. Biofilm was observed on 3 RCIs (7.14%).

CONCLUSIONS: RCIs should not be subjected to multiple uses; after the first clinical use they accumulate structural damage and dirt that hampers the cleaning step, causing failure in the sterilization process.

PRACTICAL IMPLICATIONS: The presence of microorganisms and structural damage on the RCIs confirmed that they are not amenable to processing, a fact that characterizes them as a single-use health care product.}, } @article {pmid37111983, year = {2023}, author = {Osman, RB and Khoder, G and Fayed, B and Kedia, RA and Elkareimi, Y and Alharbi, N}, title = {Influence of Fabrication Technique on Adhesion and Biofilm Formation of Candida albicans to Conventional, Milled, and 3D-Printed Denture Base Resin Materials: A Comparative In Vitro Study.}, journal = {Polymers}, volume = {15}, number = {8}, pages = {}, pmid = {37111983}, issn = {2073-4360}, support = {2201110266//University of Sharjah/ ; 11111111//Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia,/ ; }, abstract = {The aim of this study was to evaluate the adhesion and biofilm formation of Candida albicans (C. albicans) on conventionally fabricated, milled, and 3D-printed denture base resin materials in order to determine the susceptibility of denture contamination during clinical use. Specimens were incubated with C. albicans (ATCC 10231) for 1 and 24 h. Adhesion and biofilm formation of C. albicans were assessed using the field emission scanning electron microscopy (FESEM). The XTT (2,3-(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) assay was used for the quantification of fungal adhesion and biofilm formation. The data were analyzed using GraphPad Prism 8.02 for windows. One-way ANOVA with Tukey's post hoc testing were performed with a statistical significance level set at α = 0.05. The quantitative XTT biofilm assay revealed significant differences in the biofilm formation of C. albicans between the three groups in the 24 h incubation period. The highest proportion of biofilm formation was observed in the 3D-printed group, followed by the conventional group, while the lowest candida biofilm formation was observed in the milled group. The difference in biofilm formation among the three tested dentures was statistically significant (p < 0.001). The manufacturing technique has an influence on the surface topography and microbiological properties of the fabricated denture base resin material. Additive 3D-printing technology results in increased candida adhesion and the roughest surface topography of maxillary resin denture base as compared to conventional flask compression and CAD/CAM milling techniques. In a clinical setting, patients wearing additively manufactured maxillary complete dentures are thus more susceptible to the development of candida-associated denture stomatitis and accordingly, strict oral hygiene measures and maintenance programs should be emphasized to patients.}, } @article {pmid37111459, year = {2023}, author = {Doulgeraki, AI and Kamarinou, CS and Nychas, GE and Argyri, AA and Tassou, CC and Moulas, G and Chorianopoulos, N}, title = {Role of Microbial Interactions across Food-Related Bacteria on Biofilm Population and Biofilm Decontamination by a TiO2-Nanoparticle-Based Surfactant.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {37111459}, issn = {2076-0817}, abstract = {Microbial interactions play an important role in initial cell adhesion and the endurance of biofilm toward disinfectant stresses. The present study aimed to evaluate the effect of microbial interactions on biofilm formation and the disinfecting activity of an innovative photocatalytic surfactant based on TiO2 nanoparticles. Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli, Leuconostoc spp., Latilactobacillus sakei, Serratia liquefaciens, Serratia proteomaculans, Citrobacter freundii, Hafnia alvei, Proteus vulgaris, Pseudomonas fragi, and Brochothrix thermosphacta left to form mono- or dual-species biofilms on stainless steel (SS) coupons. The effectiveness of the photocatalytic disinfectant after 2 h of exposure under UV light on biofilm decontamination was evaluated. The effect of one parameter i.e., exposure to UV or disinfectant, was also determined. According to the obtained results, the microbial load of a mature biofilm depended on the different species or dual species that had adhered to the surface, while the presence of other species could affect the biofilm population of a specific microbe (p < 0.05). The disinfectant strengthened the antimicrobial activity of UV, as, in most cases, the remaining biofilm population was below the detection limit of the method. Moreover, the presence of more than one species affected the resistance of the biofilm cells to UV and the disinfectant (p < 0.05). In conclusion, this study confirms that microbial interactions affected biofilm formation and decontamination, and it demonstrates the effectiveness of the surfactant with the photocatalytic TiO2 agent, suggesting that it could be an alternative agent with which to disinfect contaminated surfaces.}, } @article {pmid37111423, year = {2023}, author = {Maione, A and Galdiero, E and Cirillo, L and Gambino, E and Gallo, MA and Sasso, FP and Petrillo, A and Guida, M and Galdiero, M}, title = {Prevalence, Resistance Patterns and Biofilm Production Ability of Bacterial Uropathogens from Cases of Community-Acquired Urinary Tract Infections in South Italy.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {37111423}, issn = {2076-0817}, abstract = {Community-acquired urinary tract infections represent the most common infectious diseases in the community setting. Knowing the antibiotic resistance patterns of uropathogens is crucial for establishing empirical treatment. The aim of the current study is to determine the incidence of the causative agents of UTIs and their resistance profiles. Patients of all ages and both sexes were enrolled in the study, and admitted to San Ciro Diagnostic Center in Naples between January 2019 and Jun 2020. Bacterial identification and antibiotic susceptibility testing were carried out using Vitek 2 system. Among the 2741 urine samples, 1702 (62.1%) and 1309 (37.9%) were negative and positive for bacterial growth, respectively. Of 1309 patients with infection, 760 (73.1%) were females and 279 (26.9%) were males. The greatest number of positive cases were found in the in the elderly (>61 years). Regarding uropathogens, 1000 (96.2%) were Gram-negative while 39 (3.8%) were Gram-positive strains. The three most isolated pathogenic strains were Escherichia coli (72.2%), Klebsiella pneumoniae (12.4%), and Proteus mirabilis (9.0%). Strong biofilm formation ability was observed in about 30% of the tested isolates. The low resistance rates recorded against nitrofurantoin, fosfomycin, piperacillin-tazobactam, and gentamicin could suggest them as the most appropriate therapies for CA-UTIs.}, } @article {pmid37111322, year = {2023}, author = {Manoharadas, S and Ahmad, N and Altaf, M and Alrefaei, AF and Al-Rayes, BF}, title = {An Enzybiotic Cocktail Effectively Disrupts Preformed Dual Biofilm of Staphylococcus aureus and Enterococcus faecalis.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {16}, number = {4}, pages = {}, pmid = {37111322}, issn = {1424-8247}, support = {15-BIO3608-02//National Plan for Science and Technology (NPST), Kingdom of Saudi Arabia/ ; }, abstract = {Multidrug-resistant bacterial infections are on the rise around the world. Chronic infections caused by these pathogens through biofilm mediation often complicate the situation. In natural settings, biofilms are often formed with different species of bacteria existing synergistically or antagonistically. Biofilms on diabetic foot ulcers are formed predominantly by two opportunistic pathogens, Staphylococcus aureus and Enterococcus faecalis. Bacteriophages and phage-based proteins, including endolysins, have been found to be active against biofilms. In this study, we evaluated the activity of two engineered enzybiotics either by themselves or as a combination against a dual biofilm formed by S. aureus and E. faecalis in an inert glass surface. An additive effect in rapidly disrupting the preformed dual biofilm was observed with the cocktail of proteins, in comparison with mono treatment. The cocktail-treated biofilms were dispersed by more than 90% within 3 h of treatment. Apart from biofilm disruption, bacterial cells embedded in the biofilm matrix were also effectively reduced by more than 90% within 3 h of treatment. This is the first instance where a cocktail of engineered enzybiotics has been effectively used to impede the structural integrity of a dual biofilm.}, } @article {pmid37110446, year = {2023}, author = {Vanheuverzwijn, J and Maillard, EE and Mahat, A and Fowler, L and Monteyne, D and Bonnaud, L and Landercy, N and Hemberg, A and Janković, A and Meyer, F and Mišković-Stanković, V and Stevanović, M and Mirica, C and Pérez-Morga, D and Luginbuehl, R and Combes, C and Furtos, G and Fontaine, V}, title = {Easy, Flexible and Standardizable Anti-Nascent Biofilm Activity Assay to Assess Implant Materials.}, journal = {Microorganisms}, volume = {11}, number = {4}, pages = {}, pmid = {37110446}, issn = {2076-2607}, abstract = {Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.}, } @article {pmid37110385, year = {2023}, author = {Kang, MS and Park, GY and Lee, AR}, title = {In Vitro Preventive Effect and Mechanism of Action of Weissella cibaria CMU against Streptococcus mutans Biofilm Formation and Periodontal Pathogens.}, journal = {Microorganisms}, volume = {11}, number = {4}, pages = {}, pmid = {37110385}, issn = {2076-2607}, support = {2020R1F1A1069551//National Research Foundation of Korea/ ; RS-2022-00167206//Ministry of Small and Medium Enterprises and Startups/ ; }, abstract = {In this study, we evaluated the in vitro anti-biofilm, antibacterial, and anti-inflammatory activity of Weissella cibaria CMU (CMU), an oral probiotic, against periodontopathogens. Compared to other oral probiotics, CMU showed a superior inhibitory effect on the biofilm formation and growth of Streptococcus mutans on orthodontic wires and artificial teeth (p < 0.05). CMU exerted potent antibacterial effects against S. mutans and Porphyromonas gingivalis according to a line test. In human gingival fibroblasts (HGFs) stimulated by P. gingivalis, Fusobacterium nucleatum, or Prevotella intermedia, CMU suppressed the gene expression of pro-inflammatory cytokines [interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor-α] in a dose-dependent manner (p < 0.05). CMU restored the production of the tissue inhibitor of metalloproteinase-1 following its inhibition by P. gingivalis, and it suppressed the expression of matrix metalloproteinase (MMP)-1 and -3 induced by periodontopathogens (p < 0.05). Moreover, CMU needed direct contact with HGFs to exert their anti-inflammatory function, indicating that they act directly on gingival cells to modulate local inflammation. Our preclinical study provides evidence for the potential benefits of topical CMU treatments in preventing the development of caries and periodontitis caused by the dysbiosis of the dental plaque microbiome.}, } @article {pmid37110336, year = {2023}, author = {Elzahaby, DA and Farrag, HA and Haikal, RR and Alkordi, MH and Abdeltawab, NF and Ramadan, MA}, title = {Inhibition of Adherence and Biofilm Formation of Pseudomonas aeruginosa by Immobilized ZnO Nanoparticles on Silicone Urinary Catheter Grafted by Gamma Irradiation.}, journal = {Microorganisms}, volume = {11}, number = {4}, pages = {}, pmid = {37110336}, issn = {2076-2607}, abstract = {Nosocomial infections caused by microbial biofilm formation on biomaterial surfaces such as urinary catheters are complicated by antibiotic resistance, representing a common problem in hospitalized patients. Therefore, we aimed to modify silicone catheters to resist microbial adherence and biofilm formation by the tested microorganisms. This study used a simple direct method to graft poly-acrylic acid onto silicone rubber films using gamma irradiation to endow the silicone surface with hydrophilic carboxylic acid functional groups. This modification allowed the silicone to immobilize ZnO nanoparticles (ZnO NPs) as an anti-biofilm. The modified silicone films were characterized by FT-IR, SEM, and TGA. The anti-adherence ability of the modified silicone films was evidenced by the inhibition of biofilm formation by otherwise strong biofilm-producing Gram-positive, Gram-negative, and yeast clinical isolates. The modified ZnO NPs grafted silicone showed good cytocompatibility with the human epithelial cell line. Moreover, studying the molecular basis of the inhibitory effect of the modified silicone surface on biofilm-associated genes in a selected Pseudomonas aeruginosa isolate showed that anti-adherence activity might be due to the significant downregulation of the expression of lasR, lasI, and lecB genes by 2, 2, and 3.3-fold, respectively. In conclusion, the modified silicone catheters were low-cost, offering broad-spectrum anti-biofilm activity with possible future applications in hospital settings.}, } @article {pmid37110286, year = {2023}, author = {Ignatova, N and Abidullina, A and Streltsova, O and Elagin, V and Kamensky, V}, title = {Effect of pH, Norepinephrine and Glucose on Metabolic and Biofilm Activity of Uropathogenic Microorganisms.}, journal = {Microorganisms}, volume = {11}, number = {4}, pages = {}, pmid = {37110286}, issn = {2076-2607}, support = {21-15-00371//Russian Science Foundation/ ; }, abstract = {Urinary tract infection (UTIs) aremainly caused by a number of anatomical and physiological dysfunctions, but there are also some iatrogenic factors, including the use of certain medications, that contribute to the development of UTIs. The virulence of bacteria that colonize the urinary tract may be modified by pH and by the presence of soluble substances in urine, such as norepinephrine (NE) and glucose. In this work, we studied the influence of NE and glucose across a range of pHs (5, 7, 8) on the biomass, matrix production and metabolism of uropathogenic strains of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus faecalis. We used Congo red and gentian violet to stain the extracellular matrix and biomass, respectively, of biofilms. The optical density of staining of the biofilms was measured using a multichannel spectrophotometer. The metabolic activity was analyzed by MTT assay. It was shown that NE and glucose stimulate biomass production both in the Gram-negative and Gram-positive uropathogens. The metabolic activity in the presence of glucose was higher at pH 5 for E. coli (in 4.0 ± 0.1 times), Ps. aeruginosa (in 8.2 ± 0.2 times) and Kl. pneumoniae (in 4.1 ± 0.2 times). Matrix production of Kl. pneumoniae increased under NE (in 8.2 ± 0.2 times) and in the presence of glucose (in 1.5 ± 0.3 times). Thus, NE and glucose in urine may lead to persistent UTI under patient stress and in the case of metabolic glucose disorders.}, } @article {pmid37109533, year = {2023}, author = {Amante, C and De Soricellis, C and Luccheo, G and Luccheo, L and Russo, P and Aquino, RP and Del Gaudio, P}, title = {Flogomicina: A Natural Antioxidant Mixture as an Alternative Strategy to Reduce Biofilm Formation.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {4}, pages = {}, pmid = {37109533}, issn = {2075-1729}, abstract = {The National Institute of Health has reported that approximately 80% of chronic infections are associated with biofilms, which are indicated as one of the main reasons for bacteria's resistance to antimicrobial agents. Several studies have revealed the role of N-acetylcysteine (NAC), in reducing biofilm formation induced by different microorganisms. A novel mixture made up of NAC and different natural ingredients (bromelain, ascorbic acid, Ribes nigrum, resveratrol, and pelargonium) has been developed in order to obtain a pool of antioxidants as an alternative strategy for biofilm reduction. The study has demonstrated that the mixture is able to significantly enhance NAC activity against different Gram-positive and Gram-negative bacteria. It has shown an increase in NAC permeation in vitro through an artificial fluid, moving from 2.5 to 8 μg/cm[2] after 30 min and from 4.4 to 21.6 μg/cm[2] after 180 min, and exhibiting a strongly fibrinolytic activity compared to the single components of the mixture. Moreover, this novel mixture has exhibited an antibiofilm activity against S aureus and the ability to reduce S. aureus growth by more than 20% in a time-killing assay, while on E. coli, and P. mirabilis, the growth was reduced by more than 80% compared to NAC. The flogomicina mixture has also been proven capable of reducing bacterial adhesion to abiotic surfaces of E.coli, by more than 11% concerning only the NAC. In combination with amoxicillin, it has been shown to significantly increase the drug's effectiveness after 14 days, offering a safe and natural way to reduce the daily dosage of antibiotics in prolonged therapies and consequently, reduce antibiotic resistance.}, } @article {pmid37108414, year = {2023}, author = {Begić, G and Badovinac, IJ and Karleuša, L and Kralik, K and Cvijanovic Peloza, O and Kuiš, D and Gobin, I}, title = {Streptococcus salivarius as an Important Factor in Dental Biofilm Homeostasis: Influence on Streptococcus mutans and Aggregatibacter actinomycetemcomitans in Mixed Biofilm.}, journal = {International journal of molecular sciences}, volume = {24}, number = {8}, pages = {}, pmid = {37108414}, issn = {1422-0067}, support = {IP-2020-02-7875//Croatian Science Foundation/ ; UNIRI-biomed-18-280 and UNIRI-biomed-18-171//University of Rijeka, Croatia/ ; }, mesh = {*Streptococcus mutans/physiology ; *Streptococcus salivarius ; Aggregatibacter actinomycetemcomitans ; Biofilms ; Homeostasis ; }, abstract = {A disturbed balance within the dental biofilm can result in the dominance of cariogenic and periodontopathogenic species and disease development. Due to the failure of pharmacological treatment of biofilm infection, a preventive approach to promoting healthy oral microbiota is necessary. This study analyzed the influence of Streptococcus salivarius K12 on the development of a multispecies biofilm composed of Streptococcus mutans, S. oralis and Aggregatibacter actinomycetemcomitans. Four different materials were used: hydroxyapatite, dentin and two dense polytetrafluoroethylene (d-PTFE) membranes. Total bacteria, individual species and their proportions in the mixed biofilm were quantified. A qualitative analysis of the mixed biofilm was performed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results showed that in the presence of S. salivarius K 12 in the initial stage of biofilm development, the proportion of S. mutans was reduced, which resulted in the inhibition of microcolony development and the complex three-dimensional structure of the biofilm. In the mature biofilm, a significantly lower proportion of the periodontopathogenic species A. actinomycetemcomitans was found in the salivarius biofilm. Our results show that S. salivarius K 12 can inhibit the growth of pathogens in the dental biofilm and help maintain the physiological balance in the oral microbiome.}, } @article {pmid37107116, year = {2023}, author = {Tomé, AR and Carvalho, FM and Teixeira-Santos, R and Burmølle, M and Mergulhão, FJM and Gomes, LC}, title = {Use of Probiotics to Control Biofilm Formation in Food Industries.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {37107116}, issn = {2079-6382}, support = {LA/P/0045/2020 (ALiCE), UIDB/00511/2020 and UIDP/00511/2020 (LEPABE)//National funds through FCT/MCTES (PIDDAC)/ ; 2022.05314.PTDC//National funds through FCT/MCTES (PIDDAC)/ ; SurfSAFE (no. 952471)//European Union's Horizon 2020 Research and Innovation Programme/ ; }, abstract = {Microorganisms tend to adhere to food contact surfaces and form biofilms, which serve as reservoirs for bacteria that can contaminate food. As part of a biofilm, bacteria are protected from the stressful conditions found during food processing and become tolerant to antimicrobials, including traditional chemical sanitisers and disinfectants. Several studies in the food industry have shown that probiotics can prevent attachment and the consequent biofilm formation by spoilage and pathogenic microorganisms. This review discusses the most recent and relevant studies on the effects of probiotics and their metabolites on pre-established biofilms in the food industry. It shows that the use of probiotics is a promising approach to disrupt biofilms formed by a large spectrum of foodborne microorganisms, with Lactiplantibacillus and Lacticaseibacillus being the most tested genera, both in the form of probiotic cells and as sources of cell-free supernatant. The standardisation of anti-biofilm assays for evaluating the potential of probiotics in biofilm control is of extreme importance, enabling more reliable, comparable, and predictable results, thus promoting significant advances in this field.}, } @article {pmid37107000, year = {2023}, author = {Tian, C and Yuan, M and Tao, Q and Xu, T and Liu, J and Huang, Z and Wu, Q and Pan, Y and Zhao, Y and Zhang, Z}, title = {Discovery of Novel Resistance Mechanisms of Vibrio parahaemolyticus Biofilm against Aminoglycoside Antibiotics.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {37107000}, issn = {2079-6382}, support = {RMB 30000//Yong Zhao/ ; RMB 20000//Zhaohuan Zhang/ ; }, abstract = {Inappropriate use of antibiotics eventually leads to the emergence of antibiotic-resistant strains and invalidates the treatment of infectious diseases. Aminoglycoside antibiotics (AGAs) are a class of broad-spectrum cationic antibiotics widely used for the treatment of Gram-negative bacterial infections. Understanding the AGA resistance mechanism of bacteria would increase the efficacy of treating these infections. This study demonstrates a significant correlation between AGA resistance and the adaptation of biofilms by Vibrio parahaemolyticus (VP). These adaptations were the result of challenges against the aminoglycosides (amikacin and gentamicin). Confocal laser scanning microscope (CLSM) analysis revealed an enclosure type mechanism where the biological volume (BV) and average thickness (AT) of V. parahaemolyticus biofilm were significantly positively correlated with amikacin resistance (BIC) (p < 0.01). A neutralization type mechanism was mediated by anionic extracellular polymeric substances (EPSs). The biofilm minimum inhibitory concentrations of amikacin and gentamicin were reduced from 32 µg/mL to 16 µg/mL and from 16 µg/mL to 4 µg/mL, respectively, after anionic EPS treatment with DNase I and proteinase K. Here, anionic EPSs bind cationic AGAs to develop antibiotic resistance. Transcriptomic sequencing revealed a regulatory type mechanism, where antibiotic resistance associated genes were significantly upregulated in biofilm producing V. parahaemolyticus when compared with planktonic cells. The three mechanistic strategies of developing resistance demonstrate that selective and judicious use of new antibiotics are needed to win the battle against infectious disease.}, } @article {pmid37106905, year = {2023}, author = {Afonso, AC and Sousa, M and Pinto, AR and Cotovio, M and Simões, M and Saavedra, MJ}, title = {Biofilm Production by Critical Antibiotic-Resistant Pathogens from an Equine Wound.}, journal = {Animals : an open access journal from MDPI}, volume = {13}, number = {8}, pages = {}, pmid = {37106905}, issn = {2076-2615}, support = {(2020.04773.BD)//FCT grant/ ; UIDB/AGR/04033/2020 (CITAB)//FCT/MCTES (PIDDAC); Germirrad-POCI-01-0247-FEDER-072237, funded by FEDER funds through COMPETE2020/ ; UIDB/CVT/00772/2020 (CECAV)//FCT/MCTES (PIDDAC); Germirrad-POCI-01-0247-FEDER-072237, funded by FEDER funds through COMPETE2020/ ; LA/P/0045/2020 (ALiCE)//FCT/MCTES (PIDDAC); Germirrad-POCI-01-0247-FEDER-072237, funded by FEDER funds through COMPETE2020/ ; UIDB/00511/2020 (LEPABE)//FCT/MCTES (PIDDAC); Germirrad-POCI-01-0247-FEDER-072237, funded by FEDER funds through COMPETE2020/ ; }, abstract = {As in human medicine, in veterinary medicine, chronic wounds are often related to polymicrobial infections and the presence of a biofilm, which compromises the effectiveness of therapeutic approaches. In this study, a Lusitano mare presented a 21-day-old chronic wound that was only being treated with an antiseptic. A swab sample was collected, and three isolates of Staphylococcus aureus and one of Pseudomonas aeruginosa were isolated. S. aureus did not show resistance to a panel of antibiotics. However, the P. aeruginosa isolate showed a resistance profile to carbapenems and fluoroquinolones, which may suggest a cross-resistance between antiseptic and antibiotics, given that no antibiotic therapy was applied to the wound or the mare in the previous year. Further experiments were conducted to assess the ability of the isolates to form biofilms, and to ascertain their susceptibility to gentamicin. The results demonstrated that the isolates produced biofilms. Gentamicin at the minimum inhibitory concentration (MIC) and 10× MIC caused biofilm removal between 59.3% and 85.7%, with the highest removal percentage being obtained for the P. aeruginosa isolate (at 10× MIC concentration). This study reveals that an equine wound was colonized by antibiotic resistant bacteria, and that all the wound colonizers could form biofilms, demonstrating the relevance of an adequate diagnosis and treatment when there is a suspicion of a biofilm-infected wound. It also highlights the possibility of resistance transmission between animals, animals and humans, or animals and the environment.}, } @article {pmid37105262, year = {2023}, author = {Cui, H and Zhang, L and Zhang, Q and Li, X and Peng, Y and Wang, C}, title = {Enhancing nitrogen removal of carbon-limited municipal wastewater in step-feed biofilm batch reactor through integration of anammox.}, journal = {Bioresource technology}, volume = {381}, number = {}, pages = {129091}, doi = {10.1016/j.biortech.2023.129091}, pmid = {37105262}, issn = {1873-2976}, mesh = {*Wastewater ; Denitrification ; Nitrogen/analysis ; Carbon ; Anaerobic Ammonia Oxidation ; Bioreactors/microbiology ; Oxidation-Reduction ; Biofilms ; *Ammonium Compounds ; Sewage/microbiology ; }, abstract = {The biological nitrogen removal of municipal wastewater was successfully improved by integrating anammox in a step-feed sequencing biofilm batch reactor. Despite fluctuating influent carbon to nitrogen ratio (1.9-5.1) and decreasing temperature (24.1-16.3 ℃), nitrogen removal efficiency of 95.9 ± 1.4 % and nitrogen removal rate of 0.23 ± 0.02 kg N/(m[3]·d) were successfully maintained without requirement of external carbon sources. The advanced removal performance was mainly attributed to the enhanced anammox. Anammox bacteria presented a high relative abundance (42.9% in biofilms, 1.5% in flocs) and anammox activity was as high as 5.42 ± 0.12 mg N/(g volatile suspended solids·h). Further analysis suggested that flexible control of influent organic and ammonium through step-feeding could provide multiple substrate supply for anammox reaction, potentially resulting in stable combination of anammox with hybrid-nitrite-shunt processes. Overall, this study provides a promising anammox-related application with simple-control step-feed strategy for enhanced and stable nitrogen removal from carbon-limited municipal wastewater.}, } @article {pmid37105205, year = {2023}, author = {Ma, Y and Aung, TT and Lakshminarayanan, R and Chua, SL}, title = {Biofilm formation and virulence potential of carbapenem-resistant Pseudomonas aeruginosa.}, journal = {The Lancet. Microbe}, volume = {}, number = {}, pages = {}, doi = {10.1016/S2666-5247(23)00097-6}, pmid = {37105205}, issn = {2666-5247}, } @article {pmid37104940, year = {2023}, author = {Hewawaduge, C and Senevirathne, A and Sivasankar, C and Lee, JH}, title = {The impact of lipid A modification on biofilm and related pathophysiological phenotypes, endotoxicity, immunogenicity, and protection of Salmonella Typhimurium.}, journal = {Veterinary microbiology}, volume = {282}, number = {}, pages = {109759}, doi = {10.1016/j.vetmic.2023.109759}, pmid = {37104940}, issn = {1873-2542}, mesh = {Mice ; Animals ; *Salmonella typhimurium ; Endotoxins ; Lipid A ; *Salmonella Vaccines ; Mice, Inbred BALB C ; Phenotype ; Biofilms ; Vaccines, Attenuated ; }, abstract = {This study presents the engineering of a less endotoxic Salmonella Typhimurium strain by manipulating the lipid-A structure of the lipopolysaccharide (LPS) component. Salmonella lipid A was dephosphorylated by using lpxE from Francisella tularensis. The 1-phosphate group from lipid-A was removed selectively, resulting in a close analog of monophosphoryl lipid A. We observed a significant impact of ∆pagL on major virulence factors such as biofilm formation, motility, persistency, and immune evasion. In correlation with biofilm and motility retardation, adhesion and invasion were elevated but with reduced intracellular survival, a favorable phenotype prospect of a vaccine strain. Western blotting and silver staining confirmed the absence of the O-antigen and truncated lipid-A core in the detoxified Salmonella mutant. In vitro and in vivo studies demonstrated that the dephosphorylated Salmonella mutant mediated lower pro-inflammatory cytokine secretion than the wild-type strain. The vaccine strains were present in the spleen and liver for five days and were cleared from the organs by day seven. However, the wild-type strain persisted in the spleen, liver, and brain, leading to sepsis-induced death. Histological evaluations of tissue samples further confirmed the reduced endotoxic activity of the detoxified Salmonella mutant. The detoxification strategy did not compromise the level of protective immunity, as the vaccine strain could enhance humoral and cellular immune responses and protect against the wild-type challenge in immunized mice.}, } @article {pmid37103266, year = {2023}, author = {Dede, M and Basche, S and Neunzehn, J and Dannemann, M and Hannig, C and Kühne, MT}, title = {Efficacy of Endodontic Disinfection Protocols in an E. faecalis Biofilm Model-Using DAPI Staining and SEM.}, journal = {Journal of functional biomaterials}, volume = {14}, number = {4}, pages = {}, pmid = {37103266}, issn = {2079-4983}, support = {WE 5838/1-1 and WE 5838/1-2, DA 1701/1-1 and DA 1701/1-2//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The aim of this study was to investigate the antimicrobial efficacy of different disinfection protocols in a novel Enterococcus faecalis biofilm model based on a visualization method and to evaluate the potential alteration of dentinal surface. A total of 120 extracted human premolars were allocated to 6 groups with different irrigation protocols. The assessment of the effectiveness of each protocol and the alteration of dentinal surface were visualized by using SEM and fluorescence microscopy (DAPI). A dense E. faecalis biofilm with a penetration depth of 289 μm (medial part of the root canal) and 93 μm (apical part) validated that the biofilm model had been successfully implemented. A significant difference between the 3% NaOCl groups and all the other groups in both observed parts of the root canal (p < 0.05) was detected. However, the SEM analysis revealed that the dentinal surface in the 3% NaOCl groups was severely altered. The established biofilm model and the visualization method based on DAPI are appropriate for bacterial quantification and evaluation of the depth effect of different disinfection protocols in the root canal system. The combination of 3% NaOCl with 20% EDTA or MTAD with PUI allows the decontamination of deeper dentine zones within the root canal but simultaneously alters the dentinal surface.}, } @article {pmid37100298, year = {2023}, author = {Svendsen, SB and Rebien Jørgensen, L and Liang, C and Carvalho, PN and Bendix Larsen, S and Bester, K}, title = {Mechanistic studies on the effect of easy degradable carbon on pharmaceuticals removal in intermittently fed moving bed biofilm reactors.}, journal = {Bioresource technology}, volume = {380}, number = {}, pages = {129084}, doi = {10.1016/j.biortech.2023.129084}, pmid = {37100298}, issn = {1873-2976}, mesh = {*Wastewater ; *Waste Disposal, Fluid ; Biofilms ; Carbon ; Bioreactors ; Pharmaceutical Preparations ; }, abstract = {This study was conducted to provide for the first time systematic data on how intermittent feeding with carbon (ethanol) affects the kinetics of pharmaceuticals degradation in a moving bed biofilm reactor (MBBR). The relationship between the degradation rate constants (K) of 36 pharmaceuticals and the length of famine was tested with 12 different feast-famine ratios: For 17 pharmaceuticals, intermittent feeding increased K with a factor of 3-17, while for six other pharmaceuticals, it decreased K. Concerning intermittent loading, three dependencies were detected: 1) for some compounds (e.g., valsartan, ibuprofen, iohexol), the K decreased linearly with carbon loading, 2) for three compounds (2 sulfonamides and benzotriazole) K increased linearly with carbon loading 3) for most compounds (e.g., beta blockers, macrocyclic antibiotics, candesartan, citalopram, clindamycin, gabapentin) K had a maximum around 6 d famine (with 2 d feast). Optimizing processes on MBBRs need therefore be conducted based on a prioritization of compounds.}, } @article {pmid37100294, year = {2023}, author = {Zhu, L and Ma, J and Yuan, H and Deng, L and Shi, Z and He, Q and Ke, S}, title = {Effects of successional sulfadiazine exposure on biofilm in moving bed biofilm reactor: Secretion of extracellular polymeric substances, community activity and functional gene expression.}, journal = {Bioresource technology}, volume = {380}, number = {}, pages = {129092}, doi = {10.1016/j.biortech.2023.129092}, pmid = {37100294}, issn = {1873-2976}, mesh = {*Sulfadiazine/pharmacology ; *Extracellular Polymeric Substance Matrix ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Proteins ; Gene Expression ; Bioreactors ; }, abstract = {The effects of sulfadiazine (SDZ) on responses of biofilm in a moving bed biofilm reactor were explored with emphasis on the changes in extracellular polymeric substances (EPS) and functional genes. It was found that 3 to 10 mg/L SDZ reduced the protein (PN) and polysaccharide (PS) contents of EPS by 28.7%-55.1% and 33.3%-61.4%, respectively. The EPS maintained high ratio of PN to PS (10.3-15.1), and the major functional groups within EPS remained unaffected to SDZ. Bioinformatics analysis showed that SDZ significantly altered the community activity such as increased expression of s_Alcaligenes faecali. Totally, the biofilm held high SDZ removal rates, which were ascribed to the self-protection by secreted EPS, and genes levels upregulation of antibiotic resistance and transporter protein. Collectively, this study provides more details on the biofilm community exposure to an antibiotic and highlights the role of EPS and functional genes in antibiotic removal.}, } @article {pmid37100251, year = {2023}, author = {Wei, T and Wang, Z and Yang, Y and Xiang, W and Liu, Y and Wu, B and Cui, X and Guo, B and Zhou, Y}, title = {Microbial niches and dynamics of antibiotic resistance genes in a bio-enhanced granular-activated carbon biofilm treating greywater.}, journal = {Chemosphere}, volume = {331}, number = {}, pages = {138774}, doi = {10.1016/j.chemosphere.2023.138774}, pmid = {37100251}, issn = {1879-1298}, mesh = {*Waste Disposal, Fluid/methods ; *Charcoal ; Bioreactors ; Nitrification ; Biofilms ; Nitrogen/analysis ; Oxygen ; Denitrification ; Sewage ; }, abstract = {Accumulation and transmission of antibiotic resistance genes (ARGs) in greywater treatment systems present risks for its reuse. In this study, a gravity flow self-supplying oxygen (O2) bio-enhanced granular activated carbon dynamic biofilm reactor (BhGAC-DBfR) was developed to treat greywater. Maximum removal efficiencies were achieved at saturated/unsaturated ratios (RSt/Ust) of 1:1.1 for chemical oxygen demand (97.6 ± 1.5%), linear alkylbenzene sulfonates (LAS) (99.2 ± 0.5%), NH4[+]-N (99.3 ± 0.7%) and total nitrogen (85.3 ± 3.2%). Microbial communities were significantly different at various RSt/Ust and reactor positions (P < 0.05). The unsaturated zone with low RSt/Ust showed more abundant microorganisms than the saturated zone with high RSt/Ust. The reactor-top community was predominant by aerobic nitrification (Nitrospira) and LAS biodegradation (Pseudomonas, Rhodobacter and Hydrogenophaga) related genera; but reactor-bottom community was predominant by anaerobic denitrification and organics removal related genera (Dechloromonas and Desulfovibrio). Most of the ARGs (e.g., intI-1, sul1, sul2 and korB) were accumulated in the biofilm, which were closely associated with microbial communities at reactor top and stratification. The saturated zone can achieve over 80% removal of the tested ARGs at all operation Phases. Results suggested that BhGAC-DBfR can provide assistance in blocking the environment dissemination of ARGs during greywater treatment.}, } @article {pmid37099227, year = {2023}, author = {Araújo, D and Gonçalves, B and Vilas Boas, D and Rodrigues, ME and Henriques, M and Silva, S}, title = {Combined Application of Antisense Oligomers to Control Transcription Factors of Candida albicans Biofilm Formation.}, journal = {Mycopathologia}, volume = {}, number = {}, pages = {}, pmid = {37099227}, issn = {1573-0832}, support = {POCI-01-0145-FEDER-028893//Fundação para a Ciência e Tecnologia/ ; POCI-01-0145-FEDER-042779//ESIF - European Structural and Investment Funds/ ; }, abstract = {Antisense oligomers (ASOs) have been little exploited to control determinants of Candida albicans virulence. Biofilm formation is an important virulence factor of C. albicans, that is regulated by a complex network of transcription factors (such as EFG1, BRG1 and ROB1). Thus, the main goal of this work was to project ASOs, based on the 2'-OMethyl chemical modification, to target BRG1 and ROB1 mRNA and to validate its application either alone or in combination with the EFG1 mRNA target, to reduce C. albicans biofilm formation. The ability of ASOs to control gene expression was evaluate by qRT-PCR. The effect on biofilm formation was determined by the total biomass quantification, and simultaneously the carbohydrates and proteins reduction on extracellular matrix. It was verified that all the oligomers were able to reduce the levels of gene expression and the ability of C. albicans to form biofilms. Furthermore, the combined application of the cocktail of ASOs enhances the inhibition of C. albicans biofilm formation, minimizing biofilm thickness by reducing the quantity of matrix content (protein and carbohydrate). So, our work confirms that ASOs are useful tools for research and therapeutic development on the control of Candida species biofilm formation.}, } @article {pmid37098964, year = {2023}, author = {Kaleta, MF and Sauer, K}, title = {MoaB1 Homologs Contribute to Biofilm Formation and Motility by Pseudomonas aeruginosa and Escherichia coli.}, journal = {Journal of bacteriology}, volume = {205}, number = {5}, pages = {e0000423}, pmid = {37098964}, issn = {1098-5530}, mesh = {*Pseudomonas aeruginosa/metabolism ; *Bacterial Proteins/metabolism ; Escherichia coli/genetics/metabolism ; Biofilms ; Recombinant Proteins/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {moaB homologs, encoding the molybdopterin biosynthetic protein B1, have been reported to be expressed under anoxic conditions and during biofilm growth in various microorganisms; however, little is known about MoaB's function. Here, we demonstrate that in Pseudomonas aeruginosa, MoaB1 (PA3915) contributes to biofilm-related phenotypes. Specifically, moaB1 expression is induced in biofilms, and insertional inactivation of moaB1 reduced biofilm biomass accumulation and pyocyanin production while enhancing swarming motility, and pyoverdine abundance without affecting attachment, swimming motility, or c-di-GMP levels. Inactivation of the highly conserved E. coli homolog of moaB1, moaBEc, likewise coincided with reduced biofilm biomass accumulation. In turn, heterologous expression of moaBEc restored biofilm formation and swarming motility by the P. aeruginosa moaB1 mutant to wild-type levels. Moreover, MoaB1 was found to interact with other conserved biofilm-associated proteins, PA2184 and PA2146, as well as the sensor-kinase SagS. However, despite the interaction, MoaB1 failed to restore SagS-dependent expression of brlR encoding the transcriptional regulator BrlR, and inactivation of moaB1 or moaBEc had no effect on the antibiotic susceptibility phenotype of biofilms formed by P. aeruginosa and E. coli, respectively. While our findings did not establish a link between MoaB1 and molybdenum cofactor biosynthesis, they suggest that MoaB1 homologs contribute to biofilm-associated phenotypes across species boundaries, possibly hinting at the existence of a previously undescribed conserved biofilm pathway. IMPORTANCE Proteins contributing to the biogenesis of molybdenum cofactors have been characterized; however, the role of the molybdopterin biosynthetic protein B1 (MoaB1) has remained elusive, and solid evidence to support its role in biosynthesis of molybdenum cofactor is lacking. Here, we demonstrate that, in Pseudomonas aeruginosa, MoaB1 (PA3915) contributes to biofilm-related phenotypes in a manner that does not support a role of MoaB1 in the biosynthesis of molybdenum cofactors.}, } @article {pmid37098957, year = {2023}, author = {Reichhardt, C}, title = {The Pseudomonas aeruginosa Biofilm Matrix Protein CdrA Has Similarities to Other Fibrillar Adhesin Proteins.}, journal = {Journal of bacteriology}, volume = {205}, number = {5}, pages = {e0001923}, pmid = {37098957}, issn = {1098-5530}, mesh = {*Extracellular Polymeric Substance Matrix/metabolism ; *Pseudomonas aeruginosa/metabolism ; Biofilms ; Cyclic GMP/metabolism ; Adhesins, Bacterial/metabolism ; Bacteria/metabolism ; Bacterial Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {The ability of bacteria to adhere to each other and both biotic and abiotic surfaces is key to biofilm formation, and one way that bacteria adhere is using fibrillar adhesins. Fibrillar adhesins share several key characteristics, including (i) they are extracellular, surface-associated proteins, (ii) they contain an adhesive domain as well as a repetitive stalk domain, and (iii) they are either a monomer or homotrimer (i.e., identical, coiled-coil) of a high molecular weight protein. Pseudomonas aeruginosa uses the fibrillar adhesin called CdrA to promote bacterial aggregation and biofilm formation. Here, the current literature on CdrA is reviewed, including its transcriptional and posttranslational regulation by the second messenger c-di-GMP as well as what is known about its structure and ability to interact with other molecules. I highlight its similarities to other fibrillar adhesins and discuss open questions that remain to be answered toward a better understanding of CdrA.}, } @article {pmid37098898, year = {2023}, author = {Razvi, E and DiFrancesco, BR and Wasney, GA and Morrison, ZA and Tam, J and Auger, A and Baker, P and Alnabelseya, N and Rich, JD and Sivarajah, P and Whitfield, GB and Harrison, JJ and Melnyk, RA and Nitz, M and Howell, PL}, title = {Small Molecule Inhibition of an Exopolysaccharide Modification Enzyme is a Viable Strategy To Block Pseudomonas aeruginosa Pel Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0029623}, pmid = {37098898}, issn = {2165-0497}, support = {MOP43998//Gouvernement du Canada | Canadian Institutes of Health Research (IRSC)/ ; FDN 154327//Gouvernement du Canada | Canadian Institutes of Health Research (IRSC)/ ; AM-2//UofA | Canadian Glycomics Network (GlycoNet)/ ; Graduate Scholarship//Cystic Fibrosis Canada (CF)/ ; Graduate Scholarship//Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada (CRSNG)/ ; Tier II Canada Research Chair//Government of Canada (Gouvernement du Canada)/ ; Tier I Canada Research Chair//Government of Canada (Gouvernement du Canada)/ ; }, mesh = {Humans ; *Polysaccharides, Bacterial ; *Pseudomonas aeruginosa/genetics ; Biofilms ; Periplasm ; Esterases ; Bacterial Proteins/genetics ; }, abstract = {Biosynthesis of the Pel exopolysaccharide in Pseudomonas aeruginosa requires all seven genes of the pelABCDEFG operon. The periplasmic modification enzyme PelA contains a C-terminal deacetylase domain that is necessary for Pel-dependent biofilm formation. Herein, we show that extracellular Pel is not produced by a P. aeruginosa PelA deacetylase mutant. This positions PelA deacetylase activity as an attractive target to prevent Pel-dependent biofilm formation. Using a high-throughput screen (n = 69,360), we identified 56 compounds that potentially inhibit PelA esterase activity, the first enzymatic step in the deacetylase reaction. A secondary biofilm inhibition assay identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) as a specific Pel-dependent biofilm inhibitor. Structure-activity relationship studies identified the thiocarbazate as a necessary functional group and that the pyridyl ring could be replaced with a phenyl substituent (compound 1). Both SK-017154-O and compound 1 inhibit Pel-dependent biofilm formation in Bacillus cereus ATCC 10987, which has a predicted extracellular PelA deacetylase in its pel operon. Michaelis-Menten kinetics determined SK-017154-O to be a noncompetitive inhibitor of PelA, while compound 1 did not directly inhibit PelA esterase activity. Cytotoxicity assays using human lung fibroblast cells showed that compound 1 is less cytotoxic than SK-017154-O. This work provides proof of concept that biofilm exopolysaccharide modification enzymes are important for biofilm formation and can serve as useful antibiofilm targets. IMPORTANCE Present in more than 500 diverse Gram-negative and 900 Gram-positive organisms, the Pel polysaccharide is one of the most phylogenetically widespread biofilm matrix determinants found to date. Partial de-N-acetylation of this α-1,4 linked N-acetylgalactosamine polymer by the carbohydrate modification enzyme PelA is required for Pel-dependent biofilm formation in Pseudomonas aeruginosa and Bacillus cereus. Given this and our observation that extracellular Pel is not produced by a P. aeruginosa PelA deactylase mutant, we developed an enzyme-based high-throughput screen and identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) and its phenyl derivative as specific Pel-dependent biofilm inhibitors. Michaelis-Menten kinetics revealed SK-017154-O is a noncompetitive inhibitor and that its noncytotoxic, phenyl derivative does not directly inhibit P. aeruginosa PelA esterase activity. We provide proof of concept that exopolysaccharide modification enzymes can be targeted with small molecule inhibitors to block Pel-dependent biofilm development in both Gram-negative and Gram-positive bacteria.}, } @article {pmid37098889, year = {2023}, author = {Jin, X and Luan, X and Xie, F and Chang, W and Lou, H}, title = {Erg6 Acts as a Downstream Effector of the Transcription Factor Flo8 To Regulate Biofilm Formation in Candida albicans.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0039323}, pmid = {37098889}, issn = {2165-0497}, support = {82273975//National Natural Science Foundation of China (NSFC)/ ; 82173703//National Natural Science Foundation of China (NSFC)/ ; //Fund for Innovative Team of Shandong University to H.L./ ; ZR2020YQ63//Nature Science Fund for Excellent Young Scholars of Shandong Province of China/ ; //Qilu Young Scholars program of Shandong University to W.C./ ; }, mesh = {*Candida albicans ; *Transcription Factors/genetics/metabolism ; Fungal Proteins/metabolism ; Hyphae ; Virulence Factors/metabolism ; Antifungal Agents/metabolism ; Biofilms ; Ergosterol ; }, abstract = {The yeast-to-hyphal morphotype transition and subsequent biofilm formation are important virulence factors of Candida albicans and are closely associated with ergosterol biosynthesis. Flo8 is an important transcription factor that determines filamentous growth and biofilm formation in C. albicans. However, the relationship between Flo8 and regulation of the ergosterol biosynthesis pathway remains elusive. Here, we analyzed the sterol composition of a flo8-deficient C. albicans strain by gas chromatography-mass spectrometry and observed the accumulation of the sterol intermediate zymosterol, the substrate of Erg6 (C-24 sterol methyltransferase). Accordingly, the transcription level of ERG6 was reduced in the flo8-deficient strain. Yeast one-hybrid experiments revealed that Flo8 physically interacted with the ERG6 promoter. Ectopic overexpression of ERG6 in the flo8-deficient strain partially restored biofilm formation and in vivo virulence in a Galleria mellonella infection model. These findings suggest that Erg6 is a downstream effector of the transcription factor Flo8 that mediates the cross talk between sterol synthesis and virulence factors in C. albicans. IMPORTANCE Biofilm formation by C. albicans hinders its eradication by immune cells and antifungal drugs. Flo8 is an important morphogenetic transcription factor that regulates the biofilm formation and in vivo virulence of C. albicans. However, little is known about how Flo8 regulates biofilm formation and fungal pathogenicity. Here, we determined that Flo8 directly binds to the promoter of ERG6 to positively regulate its transcriptional expression. Consistently, loss of flo8 results in the accumulation of the substrate of Erg6. Moreover, ectopic overexpression of ERG6 at least partially restores the biofilm formation and virulence of the flo8-deficient strain both in vitro and in vivo. This work provides a new perspective on the metabolic link between transcription factors and morphotypes in C. albicans.}, } @article {pmid37098583, year = {2023}, author = {Goswami, AG and Basu, S and Banerjee, T and Shukla, VK}, title = {Biofilm and wound healing: from bench to bedside.}, journal = {European journal of medical research}, volume = {28}, number = {1}, pages = {157}, pmid = {37098583}, issn = {2047-783X}, mesh = {Humans ; Debridement/methods ; *Wound Infection/therapy ; Wound Healing ; *Anti-Infective Agents ; Biofilms ; }, abstract = {The bubbling community of microorganisms, consisting of diverse colonies encased in a self-produced protective matrix and playing an essential role in the persistence of infection and antimicrobial resistance, is often referred to as a biofilm. Although apparently indolent, the biofilm involves not only inanimate surfaces but also living tissue, making it truly ubiquitous. The mechanism of biofilm formation, its growth, and the development of resistance are ever-intriguing subjects and are yet to be completely deciphered. Although an abundance of studies in recent years has focused on the various ways to create potential anti-biofilm and antimicrobial therapeutics, a dearth of a clear standard of clinical practice remains, and therefore, there is essentially a need for translating laboratory research to novel bedside anti-biofilm strategies that can provide a better clinical outcome. Of significance, biofilm is responsible for faulty wound healing and wound chronicity. The experimental studies report the prevalence of biofilm in chronic wounds anywhere between 20 and 100%, which makes it a topic of significant concern in wound healing. The ongoing scientific endeavor to comprehensively understand the mechanism of biofilm interaction with wounds and generate standardized anti-biofilm measures which are reproducible in the clinical setting is the challenge of the hour. In this context of "more needs to be done", we aim to explore various effective and clinically meaningful methods currently available for biofilm management and how these tools can be translated into safe clinical practice.}, } @article {pmid37098362, year = {2023}, author = {Shitu, A and Chen, W and Tadda, MA and Zhang, Y and Ye, Z and Liu, D and Zhu, S and Zhao, J}, title = {Enhanced aquaculture wastewater treatment in a biofilm reactor filled with sponge/ferrous oxalate/biochar composite (Sponge-C2FeO4@NBC) biocarriers: Performance and mechanism.}, journal = {Chemosphere}, volume = {330}, number = {}, pages = {138772}, doi = {10.1016/j.chemosphere.2023.138772}, pmid = {37098362}, issn = {1879-1298}, mesh = {*Waste Disposal, Fluid/methods ; RNA, Ribosomal, 16S ; Nitrogen/metabolism ; Biofilms ; Bioreactors ; Aquaculture ; *Water Purification ; Nitrification ; }, abstract = {Fabricating low-cost and efficient biofilm carriers for moving bed biofilm reactors in wastewater treatment is crucial for achieving environmental sustainability. Herein, a novel sponge biocarrier doped with NaOH-loaded biochar and nano ferrous oxalate (sponge-C2FeO4@NBC) was prepared and evaluated for nitrogenous compounds removal from recirculating aquaculture systems (RAS) wastewater by stepwise increasing ammonium nitrogen (NH4[+]-N) loading rates. The prepared NBC, sponge-C2FeO4@NBC, and matured biofilms were characterized using SEM, FTIR, BET, and N2 adsorption-desorption techniques. The results reveal that the highest removal rates of NH4[+]-N reached 99.28 ± 1.3% was yielded by the bioreactor filled with sponge-C2FeO4@NBC, with no obvious nitrite (NO2[-]-N) accumulation in the final phase. The reactor packed with sponge-C2FeO4@NBC biocarrier had the highest relative abundance of functional microorganisms responsible for nitrogen metabolism than in the control reactor, confirmed from 16S rRNA gene sequencing analysis. Our study provides new insights into the newly developed biocarriers for enhancing RAS biofilters treatment performance in keeping water quality within the acceptable level for the rearing of aquatic species.}, } @article {pmid37097921, year = {2023}, author = {Shastry, RP and Abhinand, CS}, title = {Targeting the Pseudomonas aeruginosa quorum sensing system to inhibit virulence factors and eradicate biofilm formation using AHL-analogue phytochemicals.}, journal = {Journal of biomolecular structure & dynamics}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/07391102.2023.2202270}, pmid = {37097921}, issn = {1538-0254}, abstract = {Quorum sensing plays a major role in the expression of virulence and development of biofilm in the human pathogen Pseudomonas aeruginosa. Natural compounds are well-known for their antibacterial characteristics by blocking various metabolic pathways. The goal of this study is to find natural compounds that mimic AHL (Acyl homoserine lactone) and suppress virulence in P. aeruginosa, which is triggered by quorum sensing-dependent pathways as an alternative drug development strategy. To support this rationale, functional network analysis and in silico investigations were carried out to find natural AHL analogues, followed by molecular docking studies. Out of the 16 top-hit AHL analogues derived from phytochemicals, seven ligands were found to bind to the quorum sensing activator proteins. Cassialactone, an AHL analogue, exhibited the highest binding affinity for RhlI, RhlR, and PqsE of P. aeruginosa, with a docking score of -9.4, -8.9, and -8.7 kcal/mol, respectively. 2(5H)-Furanone, a well-known inhibitor, was also docked to compare the docking score and intermolecular interactions between the ligand and the target protein. Furthermore, molecular dynamics simulations and binding free energy calculations were performed to determine the stability of the docked complexes. Additionally, the ADME properties of the analogues were also analyzed to evaluate the pharmacological parameters. Functional network analysis further showed that the interconnectedness of proteins such as RhlI, RhlR, LasI, and PqsE with the virulence and biofilm phenotype of the pathogen could offer potential as a therapeutic target.Communicated by Ramaswamy H. Sarma.}, } @article {pmid37097592, year = {2023}, author = {Paul, P and Roy, R and Das, S and Sarkar, S and Chatterjee, S and Mallik, M and Shukla, A and Chakraborty, P and Tribedi, P}, title = {The combinatorial applications of 1,4-naphthoquinone and tryptophan inhibit the biofilm formation of Staphylococcus aureus.}, journal = {Folia microbiologica}, volume = {}, number = {}, pages = {}, pmid = {37097592}, issn = {1874-9356}, abstract = {Microorganisms embedded within an extracellular polymeric matrix are known as biofilm. The extensive use of antibiotics to overcome the biofilm-linked challenges has led to the emergence of multidrug-resistant strains. Staphylococcus aureus is one such nosocomial pathogen that is known to cause biofilm-linked infections. Thus, novel strategies have been adopted in this study to inhibit the biofilm formation of S. aureus. Two natural compounds, namely, 1,4-naphthoquinone (a quinone derivative) and tryptophan (aromatic amino acid), have been chosen as they could independently show efficient antibiofilm activity. To enhance the antibiofilm potential, the two compounds were combined and tested against the same organism. Several experiments like crystal violet (CV) assay, protein estimation, extracellular polymeric substance (EPS) extraction, and estimation of metabolic activity confirmed that the combination of the two compounds could significantly inhibit the biofilm formation of S. aureus. To comprehend the underlying mechanism, efforts were further directed to understand whether the two compounds could inhibit biofilm formation by compromising the cell surface hydrophobicity of the bacteria. The results revealed that the cell surface hydrophobicity got reduced by ~ 49% when the compounds were applied together. Thus, the combinations could show enhanced antibiofilm activity by attenuating cell surface hydrophobicity. Further studies revealed that the selected concentrations of the compounds could disintegrate (~ 70%) the pre-existing biofilm of the test bacteria without showing any antimicrobial activity. Hence, the combined application of tryptophan and 1,4-naphthoquinone could be used to inhibit the biofilm threats of S. aureus.}, } @article {pmid37097401, year = {2023}, author = {Sun, N and Jiang, X and Meng, Q and Jiang, H and Yuan, Z and Zhang, J}, title = {Preparation of Nanoparticles Loaded with Quercetin and Effects on Bacterial Biofilm and LPS-Induced Oxidative Stress in Dugesia japonica.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {37097401}, issn = {1559-0291}, abstract = {Quercetin is a kind of flavonol compound, which has been widely concerned because of its good pharmacological effects. However, its poor water solubility and poor oral absorption limit its application. To address the above problems, the optimal technological conditions for preparing quercetin-loaded chitosan sodium alginate nanoparticles (Q-CSNPs) were obtained through single-factor experiment method. Q-CSNPs were characterized by particle size analyzer, scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR). Biofilm experiment evaluated the antibacterial activity of five different concentrations of Q-CSNPs against Escherichia coli and Staphylococcus aureus. DPPH and hydroxyl radical scavenging experiments determined their antioxidant activity. The effect of Q-CSNPs labeled with FITC on the oxidative stress of planarian was determined. The results showed that quercetin was successfully encapsulated and had good antibacterial and antioxidant capacity in vitro. In vivo experiments of planarians also showed that Q-CSNPs could inhibit the oxidative stress induced by lipopolysaccharide (LPS) and especially alleviate the decrease of CAT activity and the increase of MDA content in planarians induced by LPS. After being supported by future in vivo studies, this preparation will provide research possibilities for the development of quercetin nano-drugs, quercetin dietary supplement, and so on.}, } @article {pmid37096639, year = {2023}, author = {Chen, K and Zhu, Y and Su, H and Jiang, H and Liu, X}, title = {Modified Zhibai Dihuang pill alleviated urinary tract infection induced by extended-spectrum β-lactamase Escherichia coli in rats by regulating biofilm formation.}, journal = {Pharmaceutical biology}, volume = {61}, number = {1}, pages = {674-682}, pmid = {37096639}, issn = {1744-5116}, mesh = {Rats ; Animals ; Escherichia coli ; *Escherichia coli Infections/drug therapy/microbiology ; beta-Lactamases/genetics/metabolism ; Rats, Sprague-Dawley ; *Urinary Tract Infections/drug therapy/microbiology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {CONTEXT: Zhibai Dihuang pill (ZD), a traditional Chinese medicine nourishes Yin and reduces internal heat, is believed to have therapeutic effects on urinary tract infections (UTIs).

OBJECTIVE: To explore the effects and mechanism of modified ZD (MZD) on UTI induced by extended-spectrum β-lactamase (ESBLs) Escherichia coli.

MATERIALS AND METHODS: Thirty Sprague-Dawley rats were randomly divided into control, model (0.5 mL 1.5 × 10[8] CFU/mL ESBLs E. coli), MZD (20 g/kg MZD), LVFX (0.025 g/kg LVFX), and MZD + LVFX groups (20 g/kg MZD + 0.025 g/kg LVFX), n = 6. After 14 days of treatment, serum biochemical indicators, renal function indicators, bladder and renal histopathology, and urine bacterial counts in rats were determined. Additionally, the effects of MZD on ESBLs E. coli biofilm formation and related gene expression were analyzed.

RESULTS: MZD significantly decreased the count of white blood cells (from 13.12 to 9.13), the proportion of neutrophils (from 43.53 to 23.18), C-reactive protein (from 13.21 to 9.71), serum creatinine (from 35.78 to 30.15), and urea nitrogen (from 12.56 to 10.15), relieved the inflammation and fibrosis of bladder and kidney tissues, and reduced the number of bacteria in urine (from 2174 to 559). In addition, MZD inhibited the formation of ESBLs E. coli biofilms (2.04-fold) and decreased the gene expressions of luxS, pfS and ompA (1.41-1.62-fold).

DISCUSSION AND CONCLUSION: MZD treated ESBLs E. coli-induced UTI inhibited biofilm formation, providing a theoretical basis for the clinical application of MZD. Further study on the clinical effect of MZD may provide a novel therapy option for UTI.}, } @article {pmid37096222, year = {2023}, author = {Chiou, LL and Panariello, BHD and Hamada, Y and Gregory, RL and Blanchard, S and Duarte, S}, title = {Comparison of In Vitro Biofilm Formation on Titanium and Zirconia Implants.}, journal = {BioMed research international}, volume = {2023}, number = {}, pages = {8728499}, pmid = {37096222}, issn = {2314-6141}, mesh = {Humans ; Titanium ; *Dental Implants ; *Peri-Implantitis ; Biofilms ; Surface Properties ; }, abstract = {BACKGROUND: Peri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants.

METHODS: Biofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants.

RESULTS: Three-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm.

CONCLUSION: While early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.}, } @article {pmid37094684, year = {2023}, author = {Zhao, Q and Liu, Y and Liao, C and Yan, X and Tian, L and Li, T and Li, N and Wang, X}, title = {Reduction of S[0] deposited on electroactive biofilm under an oxidative potential.}, journal = {The Science of the total environment}, volume = {882}, number = {}, pages = {163698}, doi = {10.1016/j.scitotenv.2023.163698}, pmid = {37094684}, issn = {1879-1026}, mesh = {Biofilms ; Oxidation-Reduction ; *Geobacter/physiology ; Electrodes ; Oxidative Stress ; *Bioelectric Energy Sources ; }, abstract = {The inevitable deposition of S[0] on the electroactive biofilm (EAB) via anodic sulfide oxidation affects the stability of bioelectrochemical systems (BESs) when an accidental discharge of sulfide occurred, leading to the inhibition of electroacitivity, because the potential of anode (e.g., 0 V versus Ag/AgCl) is ~500 mV more positive than the redox potential of S[2-]/S[0]. Here we found that S[0] deposited on the EAB can be spontaneously reduced under this oxidative potential independent of microbial community variation, leading to a self-recovery of electroactivity (> 100 % in current density) with biofilm thickening (~210 μm). Transcriptomics of pure culture indicated that Geobacter highly expressed genes involving in S[0] metabolism, which had an additional benefit to improve the viability (25 % - 36 %) of bacterial cells in biofilm distant from the anode and the cellular metabolic activity via electron shuttle pair of S[0]/S[2-](Sx[2-]). Our findings highlighted the importance of spatially heterogeneous metabolism to its stability when EABs encountered with the problem of S[0] deposition, and that in turn improved the electroactivity of EABs.}, } @article {pmid37094608, year = {2023}, author = {Ravazzi, R and Neves, JG and Santamaria, MP and Rosa, LP and Rosa, FCS and Santamaria-Jr, M}, title = {Porphyrin-associated fluorescence spectroscopy (Photogen®) for the optical diagnosis of dental biofilm in orthodontic treatment: An observational clinical trial.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {42}, number = {}, pages = {103580}, doi = {10.1016/j.pdpdt.2023.103580}, pmid = {37094608}, issn = {1873-1597}, abstract = {OBJECTIVE: This study assessed the presence of dental biofilm with fluorescence spectroscopy associated with porphyrin (Photogen®) in users of orthodontic appliances.

METHODS: This cross-sectional observational clinical trial included 21 patients with metallic orthodontic fixed appliances. The presence of biofilm was evaluated by fluorescence spectroscopy (Evince-MMÓptics. São Carlos-SP, Brazil) with a porphyrin photo-evidence device (Photogen®). Digital images of the buccal surface of the upper anterior teeth (central and lateral incisors and canines) without and with porphyrin were analyzed using the histogram R (red) function in ImageJ software. The results were analyzed using the maximum and mode values of the red pixels from the histograms. The statistical analysis considered the significance level of 5%.

RESULTS: The maximum values and modes of the red pixels were significantly higher in biofilms analyzed by porphyrin-associated optical spectroscopy compared to optical spectroscopy alone.

CONCLUSIONS: Porphyrin-associated fluorescence spectroscopy was able to detect dental biofilm in the oral environment of patients with orthodontic treatment. This method better evidenced the presence of biofilm on the buccal surfaces of the upper teeth compared to that observed with fluorescence spectroscopy without porphyrin.}, } @article {pmid37094480, year = {2023}, author = {Vashistha, A and Sharma, N and Nanaji, Y and Kumar, D and Singh, G and Barnwal, RP and Yadav, AK}, title = {Quorum sensing inhibitors as Therapeutics: Bacterial biofilm inhibition.}, journal = {Bioorganic chemistry}, volume = {136}, number = {}, pages = {106551}, doi = {10.1016/j.bioorg.2023.106551}, pmid = {37094480}, issn = {1090-2120}, mesh = {*Quorum Sensing ; *Biofilms ; Bacteria ; Anti-Bacterial Agents/pharmacology/metabolism ; Bacterial Proteins/metabolism ; }, abstract = {The overuse and inappropriate use of antibiotics to treat bacterial infections has led to the development of multiple drug resistant strains. Biofilm is a complex microorganism aggregation defined by the presence of a dynamic, sticky, and protective extracellular matrix made of polysaccharides, proteins, and nucleic acids. The infectious diseases are caused by bacteria that flourish within quorum sensing (QS) mediated biofilms. Efforts to disrupt biofilms have enabled the identification of bioactive molecules produced by prokaryotes and eukaryotes. The QS system is quenched predominantly by these molecules. The phenomenon is also termed as quorum sensing (QS). Both synthetic and natural substances have been discovered to be useful in QS. This review describes natural and synthetic quorum sensing inhibitors (QSIs) with the potential to treat bacterial infections. It includes the discussion on quorum sensing, mechanism of quorum sensing, effect of substituents on the activity. These discoveries could result in effective therapies using far lower dosages of medications, particularly antibiotics, are currently needed.}, } @article {pmid37093361, year = {2023}, author = {Eshtiaghi, S and Nazari, R and Fasihi-Ramandi, M}, title = {Molecular Docking, Anti-Biofilm & Antibacterial Activities and Therapeutic Index of mCM11 Peptide on Acinetobacter baumannii Strains.}, journal = {Current microbiology}, volume = {80}, number = {6}, pages = {191}, pmid = {37093361}, issn = {1432-0991}, mesh = {Humans ; *Acinetobacter baumannii ; Molecular Docking Simulation ; Antimicrobial Cationic Peptides/chemistry ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Despite the huge efforts of microbiologists, infectious diseases have yet remained one of the leading causes of death in humans, further highlighting the research priority for controlling opportunistic pathogens. Many researchers have used antibacterial peptides to solve the problem of antibiotic resistance. This research is thus conducted to investigate the antibacterial and anti-biofilm activity of a novel modified cecropin-melittin 11-peptide with improved therapeutic properties and lower side effects. After synthesis and purification of mCM11 (NH2-WRLFRRILRVL-NH2) by solid-phase synthesis and HPLC methods, respectively, the antibacterial and biofilm inhibitory activities were explored in vitro. TMHMM was used to confirm the reaction of mCM11 on the plasma membrane of the prokaryotic cells. The interaction between mCM11 on Acinetobacter baumannii strains was investigated by molecular docking using ClusPro2.0. Hemolysis and therapeutic indexes were also calculated to quantify the relative safety and adverse effects of mCM11. According to the results, mCM11 has a high inhibitory and lethal effect on A. baumannii strains due to its cationic properties and new specific sequence. Molecular docking revealed the release of a significant amount of energy when mCM11 binds to the surface of A. baumannii in an appropriate site. The findings indicated that mCM11 IC50 (4 μg/mL) lysed 2.78% of RBCs; moreover, 8 strains of Acinetobacter baumannii showed a favorable therapeutic index. The mCM11 exhibits strong antibacterial and antibiofilm activities against A. baumannii strains, suggesting its potential therapeutic role in infections caused by these strains. Similar to its impact on A. baumannii, mCM11 could be a suitable alternative to antibiotics in combat against antibiotic-resistant bacteria in the in vivo experiments.}, } @article {pmid37091817, year = {2023}, author = {Abu-Sini, M and Al-Kafaween, MA and Al-Groom, RM and Hilmi, ABM}, title = {Comparative in vitro activity of various antibiotic against planktonic and biofilm and the gene expression profile in Pseudomonas aeruginosa.}, journal = {AIMS microbiology}, volume = {9}, number = {2}, pages = {313-331}, pmid = {37091817}, issn = {2471-1888}, abstract = {P. aeruginosa is an opportunistic pathogen that is commonly found in nosocomial infections. The purpose of this study was to investigate the effects of seven antibiotics on P. aeruginosa planktonic growth, biofilm formation, and the expression of virulence factors. These antibiotics included Ciprofloxacin (CP), Amikacin (AMK), Vancomycin (VAN), Tetracycline (TET), Gentamicin (GEN), Erythromycin (Ery), and Clindamycin (CLI). Antibiotic susceptibility testing, Minimum Bactericidal Concentration (MBC), Minimum Inhibitory Concentration (MIC), growth curve, time-kill curve, biofilm inhibition and reduction assay, and RT-qPCR were used to assess the effects of these antibiotics on P. aeruginosa planktonic and biofilm. The clear zones of inhibition against P. aeruginosa for the CP, AMK, VAN, TET, GEN, Ery, and CLI were 26 mm, 20 mm, 21 mm, 22 mm, 20 mm, 25 mm and 23 mm, respectively. The MIC values for CP, AMK, VAN, TET, GEN, Ery and CLI against P. aeruginosa ranged from 0.25 to 1 µg/mL while the MBC values ranged from 1 and 0.5 to 2 µg/mL respectively. The growth, total viable counts (TVCs), bacterial adhesion and biofilm formation of P. aeruginosa were reduced after exposure to all the tested antibiotics in a dose-dependent manner. The RT-qPCR analysis showed that all the tested antibiotics share a similar overall pattern of gene expression, with a trend toward reduced expression of the virulence genes of interest (lasR, lasI, fleN, fleQ and fleR, oprB and oprC) in P. aeruginosa. The results indicate that all of the tested antibiotics possess antimicrobial and anti-biofilm activities, and that they may be multiple inhibitors and moderators of P. aeruginosa virulence via a variety of molecular targets. This deduction requires to be investigated in vivo.}, } @article {pmid37091291, year = {2023}, author = {Velez, KEC and Leighton, RE and Decho, AW and Pinckney, JL and Norman, RS}, title = {Modeling pH and Temperature Effects as Climatic Hazards in Vibrio Vulnificus and Vibrio Parahaemolyticus Planktonic Growth and Biofilm Formation.}, journal = {GeoHealth}, volume = {7}, number = {4}, pages = {e2022GH000769}, pmid = {37091291}, issn = {2471-1403}, abstract = {Climate-induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased Vibrio spread, exposure, and infection rates, thus facilitating greater Vibrio-human interactions. Multiple efforts have been developed to predict Vibrio exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on V. vulnificus and V. parahaemolyticus planktonic and biofilm growth. Vibrio strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl2 at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm Vibrio growth within- and between-species. This study showed that temperature and pH factors significantly affect Vibrio planktonic growth rates and V. parahaemolyticus biofilm formation. Therefore, pH effects must be added to the Vibrio growth modeling efforts to better predict Vibrio risk in estuarine and coastal zones that can potentially experience the cooccurrence of Vibrio and harmful algal bloom outbreak events.}, } @article {pmid37090160, year = {2023}, author = {Qi, W and Skov, PV and de Jesus Gregersen, KJ and Pedersen, LF}, title = {A novel method to estimate biofilm activity based on enzymatic oxygen release from hydrogen peroxide decomposition.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100121}, pmid = {37090160}, issn = {2590-2075}, abstract = {Biofilm is central for biological water treatment processes in recirculating aquaculture systems (RAS). A lack of suitable methods for quantifying biofilm activity, however, makes it difficult to assess and compare the microbial status of biofilm. This type of information of the biofilm will be useful to assess the colonization status of nitrifying biocarriers or to evaluate the effect of disinfectants on the biofilm activity. Here we introduce a novel assay for rapid assessment of microbial activities in the biofilm attached on bioelements from a RAS biofilter. The assay consisted of an intermittent respirometer platform where biofilter elements were exposed to 10 mg/L hydrogen peroxide (H2O2) for 1 h, following concurrent measurements of oxygen release from the decomposition of H2O2 caused by biofilm-associated enzymes. A different number of colonized, mature bioelements from a moving bed biofilter in a freshwater RAS were tested with repeated H2O2 exposure, and compared against their autoclaved forms. A substantial increase in dissolved oxygen (DO) concentration (0.92-2.31 mg O2/L) occurred with mature bioelements during 1 h of H2O2 exposure, compared to small amounts of DO release (≤0.27 mg O2/L) with autoclaved bioelements. This substantiates that H2O2 decomposition by biofilm is mainly governed by microbial enzymatic activities. A monomolecular model fitted well with the observed oxygen release profiles of tested mature bioelements after H2O2 exposure (R[2] > 0.98). The kinetic rate constant of net oxygen release (k or , h[-1]) was proportional (R[2] for linear fit = 0.99) to the number of mature bioelements tested. Repeated exposure of H2O2 to the same bioelements did not change k or , which indicates that 10 mg/L H2O2 with an exposure time of 1 h does not suppress enzymatic activity in biofilm. Our study provides a new rapid method that allows simple quantification of microbial activity in biofilm samples from aquaculture systems, which could potentially be also applied to study biofilm from wastewater treatment plants and other industries.}, } @article {pmid37089575, year = {2023}, author = {Guo, M and Yang, K and Zhou, Z and Chen, Y and Zhou, Z and Chen, P and Huang, R and Wang, X}, title = {Inhibitory effects of Stevioside on Streptococcus mutans and Candida albicans dual-species biofilm.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1128668}, pmid = {37089575}, issn = {1664-302X}, abstract = {INTRODUCTION: Streptococcus mutans is the most prevalent biofilm-forming pathogen in dental caries, while Candida albicans is often detected in the presence of S. mutans.

METHODS: We aimed to evaluate the anti-caries effect of stevioside in medium trypticase soy broth (TSB) with or without sucrose supplementation compared with the same sweetness sucrose and xylitol in a dual-species model of S. mutans and C. albicans, based on planktonic growth, crystal violet assay, acid production, biofilm structural imaging, confocal laser scanning microscopy, and RNA sequencing.

RESULTS: Our results showed that compared with sucrose, stevioside significantly inhibited planktonic growth and acid production, changed the structure of the mixed biofilm, and reduced the viability of biofilm and the production of extracellular polysaccharides in dual-species biofilm. Through RNA-seq, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway impact analysis showed that stevioside decreased sucrose metabolism and increased galactose and intracellular polysaccharide metabolism in S. mutans, and decreased genes related to GPI-modified proteins and secreted aspartyl proteinase (SAP) family in C. albicans. In contrast to xylitol, stevioside also inhibited the transformation of fungal morphology of C. albicans, which did not form mycelia and thus had reduced pathogenicity. Stevioside revealed a superior suppression of dual-species biofilm formation compared to sucrose and a similar anti-caries effect with xylitol. However, sucrose supplementation diminished the suppression of stevioside on S. mutans and C. albicans.

CONCLUSIONS: Our study is the first to confirm that stevioside has anticariogenic effects on S. mutans and C. albicans in a dual-species biofilm. As a substitute for sucrose, it may help reduce the risk of developing dental caries.}, } @article {pmid37089551, year = {2023}, author = {Wu, T and Zhong, L and Pang, JW and Ren, NQ and Ding, J and Yang, SS}, title = {Effect of Fe[3+] on the nutrient removal performance and microbial community in a biofilm system.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1140404}, pmid = {37089551}, issn = {1664-302X}, abstract = {In this study, the influence of Fe[3+] on N removal, microbial assembly, and species interactions in a biofilm system was determined. The results showed that maximum efficiencies of ammonia nitrogen (NH4 [+]-N), total nitrogen (TN), phosphorus (P), and chemical oxygen demand (COD) removal were achieved using 10 mg/L Fe[3+], reaching values of 100, 78.85, 100, and 95.8%, respectively, whereas at concentrations of 15 and 30 mg/L Fe[3+] suppressed the removal of NH4 [+]-N, TN, and COD. In terms of absolute abundance, the expression of bacterial amoA, narG, nirK, and napA was maximal in the presence of 10 mg/L Fe[3+] (9.18 × 10[5], 8.58 × 10[8], 1.09 × 10[8], and 1.07 × 10[9] copies/g dry weight, respectively). Irrespective of Fe[3+] concentrations, the P removal efficiency remained at almost 100%. Candidatus_Competibacter (10.26-23.32%) was identified as the most abundant bacterial genus within the system. Determinism (50%) and stochasticity (50%) contributed equally to microbial community assembly. Co-occurrence network analysis revealed that in the presence of Fe[3+], 60.94% of OTUs in the biofilm system exhibited positive interactions, whereas 39.06% exhibited negative interactions. Within the OTU-based co-occurrence network, fourteen species were identified as key microbes. The stability of the system was found to be predominantly shaped by microbial cooperation, complemented by competition for resources or niche incompatibility. The results of this study suggested that during chemical P removal in wastewater treatment plants using biofilm methods, the concentration of supplemental Fe[3+] should be maintained at 10 mg/L, which would not only contribute to P elimination, but also enhance N and COD removal.}, } @article {pmid37089543, year = {2023}, author = {Clarke, OE and Pelling, H and Bennett, V and Matsumoto, T and Gregory, GE and Nzakizwanayo, J and Slate, AJ and Preston, A and Laabei, M and Bock, LJ and Wand, ME and Ikebukuro, K and Gebhard, S and Sutton, JM and Jones, BV}, title = {Lipopolysaccharide structure modulates cationic biocide susceptibility and crystalline biofilm formation in Proteus mirabilis.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1150625}, pmid = {37089543}, issn = {1664-302X}, abstract = {Chlorhexidine (CHD) is a cationic biocide used ubiquitously in healthcare settings. Proteus mirabilis, an important pathogen of the catheterized urinary tract, and isolates of this species are often described as "resistant" to CHD-containing products used for catheter infection control. To identify the mechanisms underlying reduced CHD susceptibility in P. mirabilis, we subjected the CHD tolerant clinical isolate RS47 to random transposon mutagenesis and screened for mutants with reduced CHD minimum inhibitory concentrations (MICs). One mutant recovered from these screens (designated RS47-2) exhibited ~ 8-fold reduction in CHD MIC. Complete genome sequencing of RS47-2 showed a single mini-Tn5 insert in the waaC gene involved in lipopolysaccharide (LPS) inner core biosynthesis. Phenotypic screening of RS47-2 revealed a significant increase in cell surface hydrophobicity and serum susceptibility compared to the wildtype, and confirmed defects in LPS production congruent with waaC inactivation. Disruption of waaC was also associated with increased susceptibility to a range of other cationic biocides but did not affect susceptibility to antibiotics tested. Complementation studies showed that repression of smvA efflux activity in RS47-2 further increased susceptibility to CHD and other cationic biocides, reducing CHD MICs to values comparable with the most CHD susceptible isolates characterized. The formation of crystalline biofilms and blockage of urethral catheters was also significantly attenuated in RS47-2. Taken together, these data show that aspects of LPS structure and upregulation of the smvA efflux system function in synergy to modulate susceptibility to CHD and other cationic biocides, and that LPS structure is also an important factor in P. mirabilis crystalline biofilm formation.}, } @article {pmid37088696, year = {2023}, author = {Ryder, M and deLancey-Pulcini, E and Parker, AE and James, GA}, title = {Bacterial transfer and biofilm formation in needleless connectors in a clinically simulated in vitro catheter model.}, journal = {Infection control and hospital epidemiology}, volume = {}, number = {}, pages = {1-9}, doi = {10.1017/ice.2023.60}, pmid = {37088696}, issn = {1559-6834}, abstract = {OBJECTIVE: Although needleless connectors (NCs) are widely used in clinical practice, they carry significant risk of bloodstream infection (BSI). In this study, we quantified differences in bacterial transfer and biofilm formation between various NCs.

DESIGN: Prospective, clinically simulated in vitro experimental study.

METHODS: We tested 20 NCs in a 5-day clinical simulation of Staphylococcus aureus inoculations onto NC septum surfaces, which were then flushed with saline and cultured for bacterial transfer. Biofilm formation was measured through destructive sampling of the connector-catheter system. Moreover, 8 NC design factors were evaluated for their influence on bacterial transfer and biofilm formation. This study was designed without a disinfection protocol to ascertain the intrinsic risk of each NC.

RESULTS: Clave Neutron and MicroClave had the lowest overall mean log density of bacteria in the flush compared to other NCs (P < .05), except there were no statistically significant differences between Clave Neutron, Microclave, SafeTouch, and SafeAccess (P ≥ .05). The amount of biofilm in the NC was positively associated with bacteria in the flush (P < .0005). Among 8 design factors, flow path was most important, with the internal cannula associated with a statistically significant 1 log reduction (LR) in bacteria in the flush (R[2] = 49%) and 0.5-2 LR in the connector (R[2] = 34%). All factors together best explained bacteria in the flush (R[2] = 65%) and biofilm in the connector (R[2] = 48%).

CONCLUSIONS: Bacterial transfer and biofilm formation in the connector-catheter system varied statistically significantly between the 20 NCs, suggesting that NC choice can lower the risk of developing catheter-related BSIs.}, } @article {pmid37088385, year = {2023}, author = {Wang, Q and Zhang, Y and Chen, H and Chen, S and Wang, Y}, title = {Effects of humic acids on the adsorption of Pb(II) ions onto biofilm-developed microplastics in aqueous ecosystems.}, journal = {The Science of the total environment}, volume = {882}, number = {}, pages = {163466}, doi = {10.1016/j.scitotenv.2023.163466}, pmid = {37088385}, issn = {1879-1026}, mesh = {Microplastics ; Plastics ; Humic Substances ; Lead ; Adsorption ; *Water Pollutants, Chemical/analysis ; *Metals, Heavy ; Water ; Ions ; Biofilms ; *Microbiota ; }, abstract = {Microplastics (MPs), as emerging contaminants can behave as carriers for heavy metals in the water environments. Although the adsorption performance of heavy metals on MPs has been widely investigated, the effects of humic acids (HA) on the adsorption have seldom been explored. The authors were compared the Pb(II) adsorption onto biofilm-developed polyvinyl chloride (Bio-PVC) MPs with Pb(II) adsorption onto virgin PVC MPs (V-PVC), and explored the relationship between surface characteristics and the adsorption properties in the coexistence of HA. Our results showed that due to a larger specific surface area and more oxygen containing groups, Bio-PVC had a larger adsorption capability with a value of 3.57 mg/g than original ones (1.85 mg/g) due to its huge specific surface area and more oxygen containing groups. Microbial community analysis showed that the predominate bacteria in biofilms as Proteobacteria, Acidobacteria, Cyanobacteria, Firmicutes, and Bacteroidetes. Notably, the Pb(II) adsorption onto the V-PVC surfaces was increased, but the adsorption capacities of Pb(II) on Bio-PVC were suppressed with increasing HA. With the co-existence of HA, the increasing complexation and electrostatic attraction had attributed to the increased Pb(II) adsorption ability on V-PVC. Except for its competitive ability, HA has a shield effect which decreases the sorption sites on Bio-PVC. Overall, our findings provide a better understanding of the HA effect on the adsorption mechanism of heavy metals onto MPs in aquatic ecosystems.}, } @article {pmid37087512, year = {2023}, author = {Feng, W and Yang, J and Ma, Y and Zhang, L and Yin, R and Qiao, Z and Ji, Y and Zhou, Y}, title = {Relationships between Secreted Aspartyl Proteinase 2 and General Control Nonderepressible 4 gene in the Candida albicans resistant to itraconazole under planktonic and biofilm conditions.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {2}, pages = {619-627}, pmid = {37087512}, issn = {1678-4405}, support = {82072262//the General Project of the National Natural Science Foundation of China/ ; 201903D321123//Research and Development Key Projects of Shanxi Province/ ; Project Number:20210030//Scientific and Technological Activities funding program for Overseas Students of Shanxi Province/ ; 2020-190//Research Project Supported by Shanxi Scholarship Council of China/ ; }, mesh = {*Candida albicans/genetics/metabolism ; Itraconazole/pharmacology ; Fungal Proteins/genetics/metabolism ; *Aspartic Acid Proteases/genetics ; Aspartic Acid Endopeptidases/genetics ; RNA, Messenger/genetics ; Antifungal Agents/pharmacology ; }, abstract = {This study aimed to explore the roles of SAP2 and GCN4 in itraconazole (ITR) resistance of C. albicans under different conditions, and their correlations. A total of 20 clinical strains of C. albicans, including 10 ITR resistant strains and 10 sensitive strains, were used. Then, SAP2 sequencing and GCN4 sequencing were performed, and the biofilm formation ability of different C. albicans strains was determined. Finally, real-time quantitative PCR was used to measure the expression of SAP2 and GCN4 in C. albicans under planktonic and biofilm conditions, as well as their correlation was also analyzed. No missense mutations and three synonymous mutation sites, including T276A, G543A, and A675C, were found in SAP2 sequencing. GCN4 sequencing showed one missense mutation site (A106T (T36S)) and six synonymous mutation sites (A147C, C426T, T513C, T576A, G624A and C732T). The biofilm formation ability of drug-resistant C. albicans strains was significantly higher than that of sensitive strains (P < 0.05). Additionally, SAP2 and GCN4 were up-regulated in the ITR-resistant strains, and were both significantly higher in C. albicans under biofilm condition. The mRNA expression levels of SAP2 and GCN4 had significantly positive correlation. The higher expression levels of SAP2 and GCN4 were observed in the ITR-resistant strains of C. albicans under planktonic and biofilm conditions, as well as there was a positive correlation between SAP2 and GCN4 mRNA expression.}, } @article {pmid37087265, year = {2023}, author = {Wang, Y and Wu, Y and Niu, H and Liu, Y and Ma, Y and Wang, X and Li, Z and Dong, Q}, title = {Different cellular fatty acid pattern and gene expression of planktonic and biofilm state Listeria monocytogenes under nutritional stress.}, journal = {Food research international (Ottawa, Ont.)}, volume = {167}, number = {}, pages = {112698}, doi = {10.1016/j.foodres.2023.112698}, pmid = {37087265}, issn = {1873-7145}, mesh = {*Fatty Acids/metabolism ; *Listeria monocytogenes ; Food Microbiology ; Plankton/genetics ; Biofilms ; Gene Expression ; }, abstract = {Listeria monocytogenes is a Gram-positive bacterium frequently involved in food-borne disease outbreaks and is widely distributed in the food-processing environment. This work aims to depict the impact of nutrition deficiency on the survival strategy of L. monocytogenes both in planktonic and biofilm states. In the present study, cell characteristics (autoaggression, hydrophobicity and motility), membrane fatty acid composition of MRL300083 (Lm83) in the forms of planktonic and biofilm-associated cells cultured in TSB-YE and 10-fold dilutions of TSB-YE (DTSB-YE) were investigated. Additionally, the relative expression of related genes were also determined by RT-qPCR. It was observed that cell growth in different bacterial life modes under nutritional stress rendered the cells a distinct phenotype. The higher autoaggression (AAG) and motility of the planktonic cells in DTSB-YE is associated with better biofilm formation. An increased proportion of unsaturated fatty acid/saturated fatty acid (USFA/SFA) indicates more fluidic biophysical properties for cell membranes of L. monocytogenes in planktonic and biofilm cells in DTSB-YE. Biofilm cells produced a higher percentage of USFA and straight fatty acids than the corresponding planktonic cells. An appropriate degree of membrane fluidity is crucial for survival, and alteration of membrane lipids is an essential adaptive response. The adaptation of bacteria to stress is a multifactorial cellular process, the expression of flagella-related genes fliG, fliP, flgE and the two-component chemotactic system cheA/Y genes of planktonic cells in DTSB-YE significantly increased compared to that in TSB-YE (p < 0.05). This study provides new information on the role of the physiological adaptation and gene expression of L. monocytogenes for planktonic and biofilm growth under nutritional stress.}, } @article {pmid37086710, year = {2023}, author = {Arslan, E and Coşkun, MK and Çobanoğlu, Ş and Aslan, MH and Yazıcı, A}, title = {Effects of four antibiotics on Pseudomonas aeruginosa motility, biofilm formation, and biofilm-specific antibiotic resistance genes expression.}, journal = {Diagnostic microbiology and infectious disease}, volume = {106}, number = {3}, pages = {115931}, doi = {10.1016/j.diagmicrobio.2023.115931}, pmid = {37086710}, issn = {1879-0070}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; Pseudomonas aeruginosa/genetics ; *Fosfomycin/pharmacology ; Drug Resistance, Microbial ; Microbial Sensitivity Tests ; Biofilms ; *Pseudomonas Infections ; }, abstract = {The aim of this study was to determine the effects of 4 antibiotics (tobramycin, fosfomycin, ciprofloxacin, and piperacillin/tazobactam) against Pseudomonas aeruginosa motility, biofilm formation, and biofilm resistance gene expression changes using different methods including microscopy, microdilution, crystal violet staining, and qRT-PCR. Although the antibiotics reduced swarming motility, they inhibited biofilm formation to a greater extent than the minimum inhibitory concentration (MIC) value. The qRT-PCR results showed that the antibiotics, other than fosfomycin, decreased the expression levels of the selected biofilm resistance genes (ndvB, tssC1, PA5033 and PA2070) in the biofilm structure compared to planktonic cells. Furthermore, it was found that there was an increase in the expression levels of biofilm resistance genes in the antibiotic application groups compared to the biofilm structure that was not treated with antibiotics. These results showed for the first time that the treatment of antibiotics at sub-MIC concentrations increases the expression levels of biofilm-specific resistance genes and contributes to resistance and motility.}, } @article {pmid37086303, year = {2023}, author = {Marchi, AP and Farrel Côrtes, M and Vásconez Noguera, S and Rossi, F and Levin, AS and Figueiredo Costa, S and Perdigão Neto, LV}, title = {Chlorhexidine susceptibility and Eagle effect in planktonic cells and biofilm of nosocomial isolates.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {42}, number = {6}, pages = {787-792}, pmid = {37086303}, issn = {1435-4373}, mesh = {Animals ; Humans ; Chlorhexidine/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Eagles ; Plankton ; *Cross Infection ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {The aim of this study is to evaluate the chlorhexidine gluconate (CHG) susceptibility in both planktonic cells and biofilm of 32 Gram-negative (Gn) and 6 Gram-positive (Gp) isolates by minimal inhibitory concentration (2-256 μg/mL for Gn and 2-32 μg/mL for Gp), minimal bactericidal concentration (4-256 μg/mL for Gn and 2-32 μg/mL for Gp) in planktonic cells, and minimal biofilm elimination concentration (128 ≥ 16,384 μg/mL in Gn and 32 ≥ 16,384 μg/mL in Gp) in biofilm environment. Our study showed that Gn isolates have higher minimal concentrations than Gp and bacteria in biofilms are more tolerant than planktonic ones. No correlation between MBC or MBEC and biofilm formation was statistically confirmed. The Eagle effect, previously described for antimicrobials and antifungals, was evidenced in this work for CHG, an antiseptic. Besides that, the phenomenon was described in 23/38 isolates (60.5%), raising minimal concentration up to ≥ 16,384 μg/mL. Our study showed that clinical isolates have a high ability to form biofilm allowing them to tolerate CHG concentrations as high as the ones used in clinical practice. Therefore, attention should be given to the occurrence of this phenomenon to avoid false susceptibility results.}, } @article {pmid37085670, year = {2023}, author = {Tsarenko, SV and Zigangirova, NA and Soloveva, AV and Bondareva, NE and Koroleva, EA and Sheremet, AB and Kapotina, LN and Shevlyagina, NV and Andreevskaya, SG and Zhukhovitsky, VG and Filimonova, EV and Gintsburg, AL}, title = {A novel antivirulent compound fluorothiazinone inhibits Klebsiella pneumoniae biofilm in vitro and suppresses model pneumonia.}, journal = {The Journal of antibiotics}, volume = {}, number = {}, pages = {}, pmid = {37085670}, issn = {1881-1469}, abstract = {The problematic treatment of infections caused by multiple-resistant Klebsiella, especially in ICU, is the leading cause of prolonged hospitalization and high mortality rates. The use of antibiotics for the prevention of infections is considered unreasonable as it may contribute to the selection of resistant bacteria. In this regard, the development of drugs that will be effective in preventing infection during various invasive procedures is extremely necessary. We have shown that the developed innovative antibacterial compound fluorothiazinone (FT) that suppresses the formation of biofilms is effective in the prevention of a model pneumonia caused by a multi-resistant clinical K. pneumoniae isolate. Prophylactic use followed by treatment with FT in mice with acute pneumonia modulates the local innate immune response without suppressing protective properties in the early stages of infection, while contributing to a decrease in the bacterial load in the organs and preventing lethal pathological changes in the lungs at later stages of K. pneumoniae infection. Further development of such antivirulence drugs and their use will reduce morbidity and mortality in nosocomial infections, as well as reduce the number of antibiotics used.}, } @article {pmid37085401, year = {2023}, author = {Lü, J and Ren, G and Hu, Q and Rensing, C and Zhou, S}, title = {Microbial biofilm-based hydrovoltaic technology.}, journal = {Trends in biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tibtech.2023.03.012}, pmid = {37085401}, issn = {1879-3096}, abstract = {Hydrovoltaic electricity generation (HEG) utilizes the latent environmental heat stored in water, and subsequently harvests the electrical energy. However, sustainable HEG has remained extremely challenging due either to complex fabrication and high cost, or to restricted environmental compatibility and renewability. Electroactive microorganisms are environmentally abundant and viable in performing directional electron transport to produce currents. These distinctive features have inspired microbial HEG systems that can convert environmental energy into hygroelectricity upon water circulation from raindrops, waves, and water moisture, and has recently succeeded as proof of concept for becoming a cutting-edge biotechnology. In this review, recent advances in microbial biofilm-based hydrovoltaic technology are highlighted to better understand a promising method of electricity generation from environmental energy with the aim of practical applications.}, } @article {pmid37085193, year = {2023}, author = {Cai, JN and Kim, D}, title = {Biofilm ecology associated with dental caries: understanding of microbial interactions in oral communities leads to development of therapeutic strategies targeting cariogenic biofilms.}, journal = {Advances in applied microbiology}, volume = {122}, number = {}, pages = {27-75}, doi = {10.1016/bs.aambs.2023.02.001}, pmid = {37085193}, issn = {0065-2164}, mesh = {Humans ; *Dental Caries ; Virulence ; Ecology ; Biofilms ; Microbial Interactions ; }, abstract = {A biofilm is a sessile community characterized by cells attached to the surface and organized into a complex structural arrangement. Dental caries is a biofilm-dependent oral disease caused by infection with cariogenic pathogens, such as Streptococcus mutans, and associated with frequent exposure to a sugar-rich diet and poor oral hygiene. The virulence of cariogenic biofilms is often associated with the spatial organization of S. mutans enmeshed with exopolysaccharides on tooth surfaces. However, in the oral cavity, S. mutans does not act alone, and several other microbes contribute to cariogenic biofilm formation. Microbial communities in cariogenic biofilms are spatially organized into complex structural arrangements of various microbes and extracellular matrices. The balance of microbiota diversity with reduced diversity and a high proportion of acidogenic-aciduric microbiota within the biofilm is closely related to the disease state. Understanding the characteristics of polymicrobial biofilms and the association of microbial interactions within the biofilm (e.g., symbiosis, cooperation, and competition) in terms of their potential role in the pathogenesis of oral disease would help develop new strategies for interventions in virulent biofilm formation.}, } @article {pmid37083842, year = {2023}, author = {Fernandes, M and González-Ballesteros, N and da Costa, A and Machado, R and Gomes, AC and Rodríguez-Argüelles, MC}, title = {Antimicrobial and anti-biofilm activity of silver nanoparticles biosynthesized with Cystoseira algae extracts.}, journal = {Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry}, volume = {28}, number = {4}, pages = {439-450}, pmid = {37083842}, issn = {1432-1327}, mesh = {Silver/pharmacology/chemistry ; *Metal Nanoparticles/chemistry ; Antioxidants/pharmacology ; Plant Extracts/pharmacology/chemistry ; *Anti-Infective Agents ; Anti-Bacterial Agents ; Escherichia coli ; Biofilms ; *Phaeophyta ; Microbial Sensitivity Tests ; }, abstract = {Antimicrobial resistance is an ever-growing global concern to public health with no clear or immediate solution. Silver nanoparticles (AgNPs) have long been proposed as efficient agents to fight the growing number of antibiotic-resistant strains. However, the synthesis of these particles is often linked to high costs and the use of toxic, hazardous chemicals, with environmental and health impact. In this study, we successfully produced AgNPs by green synthesis with the aid of the extract of two brown algae-Cystoseira baccata (CB) and Cystoseira tamariscifolia (CT)-and characterized their physico-chemical properties. The NPs produced in both cases (Ag@CB and Ag@CT) present similar sizes, with mean diameters of around 22 nm. The antioxidant activity of the extracts and the NPs was evaluated, with the extracts showing important antioxidant activity. The bacteriostatic and bactericidal properties of both Ag@CB and Ag@CT were tested and compared with gold NPs produced in the same algae extracts as previously reported. AgNPs demonstrated the strongest bacteriostatic and bactericidal properties, at concentrations as low as 2.16 µg/mL against Pseudomonas aeruginosa and Escherichia coli. Finally, the capacity of these samples to prevent the formation of biofilms characteristic of infections with a poorer outcome was assessed, obtaining similar results. This work points towards an alternative for the treatment of bacterial infections, even biofilm-inducing, with the possibility of minimizing the risk of drug resistance, albeit the necessary caution implied using metallic NPs.}, } @article {pmid37082420, year = {2023}, author = {Marienborg, K and Ambur, OH and Økstad, OAL and Skaare, D}, title = {The alginate polymer OligoG alters susceptibility of biofilm-embedded non-typeable Haemophilus influenzae to ampicillin and ciprofloxacin.}, journal = {JAC-antimicrobial resistance}, volume = {5}, number = {2}, pages = {dlad046}, pmid = {37082420}, issn = {2632-1823}, abstract = {OBJECTIVES: Treatment of respiratory infections with non-typeable Haemophilus influenzae (NTHi) in COPD patients is complicated by biofilm formation, protecting the bacteria against the hosts' immune response and antibiotics. We investigated the antibiofilm and antibacterial effects of the alginate polymer OligoG, alone or combined with ampicillin or ciprofloxacin, on mature NTHi biofilms.

MATERIALS AND METHODS: Two unrelated COPD strains with PBP3-mediated β-lactam resistance, with additional TEM-1 β-lactamase (Hi-022) or quinolone resistance due to altered GyrA and ParC (Hi-072) were used. Antibiofilm and antibacterial effects were assessed macroscopically, by measurement of biofilm biomass (OD), and by viable cell counts, with determination of minimum biofilm inhibitory concentration (MBIC) and the novel parameter 'minimum concentration for 2 log10 drop in viable cells in biofilm' (MB2LDC). Drug interactions between OligoG and antibiotics were assessed by comparing expected and observed inhibitory effects (percent inhibition of no-treatment control) of combined treatment.

RESULTS: OligoG had dose-dependent biofilm disruptive abilities and a weak inhibitory effect on viable cells. Combination with OligoG (64 g/L) significantly lowered MBIC for ampicillin (both strains) and MB2LDC for ciprofloxacin (Hi-022). For Hi-022, there was significant synergism between OligoG and both antibiotics. For Hi-072, interactions were subtle, but a tendency in direction of antagonism was significant at two concentrations of ciprofloxacin.

CONCLUSIONS: OligoG shows promise as a potential adjuvant to antibiotics in NTHi infections, but strain-specific factors appear to affect drug interactions and may lead to antagonism. More research is needed to clarify the mechanisms of action of OligoG and interactions with antibiotics.}, } @article {pmid37082178, year = {2023}, author = {Pang, L and Lin, H and Yang, F and Deng, D}, title = {Editorial: Mechanisms of biofilm development and antibiofilm strategies.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1190611}, pmid = {37082178}, issn = {1664-302X}, } @article {pmid37081770, year = {2023}, author = {Yang, X and Lan, W and Xie, J}, title = {Inhibitory effect of chlorogenic acid-grafted chitosan on seafood isolates Pseudomonas fluorescens and its biofilm.}, journal = {Letters in applied microbiology}, volume = {76}, number = {4}, pages = {}, doi = {10.1093/lambio/ovad050}, pmid = {37081770}, issn = {1472-765X}, support = {31972142//National Natural Science Foundation of China/ ; 19DZ2284000//Shanghai Municipal Science and Technology Commission Engineering Center/ ; 20DZ2292200//Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation/ ; }, mesh = {*Chitosan/pharmacology/chemistry ; *Pseudomonas fluorescens/physiology ; Chlorogenic Acid/pharmacology ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; Seafood/microbiology ; }, abstract = {This study aimed to examine the inhibition of chlorogenic acid-grafted chitosan (CS-g-CA) on Pseudomonas fluorescens (P. fluorescens) and its biofilm. The minimum inhibitory concentration (MIC) of CS-g-CA against P. fluorescens was 1.25 mg/mL. Alkaline phosphatase (AKPase) leakage assay and scanning electron microscopy (SEM) observation showed that CS-g-CA causes structural damage to cell walls and membranes, resulting in the loss of function. In addition, CS-g-CA was able to disrupt the antioxidant system of P. fluorescens, interfere with energy metabolism, and interact with genomic DNA, affecting the normal physiological function of bacteria. It was also found that CS-g-CA inhibited the flagellar motility of P. fluorescens, which may be responsible for the inhibition of its biofilm formation. CS-g-CA at 2MIC was able to remove 71.64% of the mature biofilm and reduce the production of extracellular polysaccharides (EPS) by 60.72%. This was further confirmed by confocal laser scanning microscopy (CLSM), which showed a significant reduction in the amount of biofilm. In summary, CS-g-CA has strong antibacterial and anti-biofilm activities against P. fluorescens, and it can be applied as a potential seafood bacteriostatic agent.}, } @article {pmid37081415, year = {2023}, author = {Shaaban, S and Genena, S and Elraggal, A and Hamad, GM and Meheissen, MA and Moussa, S}, title = {Antibacterial effectiveness of multi-strain probiotics supernatants intracanal medication on Enterococcus faecalis biofilm in a tooth model.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {228}, pmid = {37081415}, issn = {1472-6831}, mesh = {Humans ; *Chlorhexidine ; *Enterococcus faecalis ; Poloxamer ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria ; Biofilms ; Calcium Hydroxide/pharmacology/therapeutic use ; Root Canal Irrigants ; Dental Pulp Cavity/microbiology ; }, abstract = {BACKGROUND: To assess the antibacterial activity of multi-strain probiotics supernatants (MSP); Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus acidophilus as an intracanal medication on Enterococcus faecalis (E. faecalis) biofilm in a tooth model.

METHODS: Sixty extracted human single-rooted teeth with single canals were instrumented, sterilized, and inoculated with E. faecalis. After 21 days of incubation, four specimens were randomly selected to validate the biofilm formation by scanning electron microscope (SEM). The remaining specimens were randomly divided (n = 14), according to the intracanal medication (ICM) received into: Ca(OH)2: calcium hydroxide paste (35% Ultra Cal XS Ca(OH)2), Probiotics supernatants: MSP in poloxamer gel vehicle Poloxamer: poloxamer gel vehicle and, Control: E. faecalis biofilm only. The tested groups were further subdivided into two equal subgroups (n = 7) according to the incubation period (24 h and 7 days). Shaved dentin chips were obtained and collected by H-files and paper points, respectively for bacterial culture. The antibacterial activity was assessed after each incubation period quantitatively and qualitatively using bacterial colony-forming units per milliliter (CFUs/ml) and SEM, respectively.

RESULTS: The lowest CFUs/ml was found in Ca (OH)2 with a significant difference compared to other groups after 24 h. After 7 days, a similar outcome was found with a further significant reduction of CFUs/ml in all groups with no statistical difference between Ca(OH)2 and probiotics supernatants groups. Ca (OH)2 and Probiotics supernatants groups showed a significant (p < 0.05) percentage of overall bacterial reduction (100.00 ± 0.00% and 70.30 ± 12.95%, respectively) compared to poloxamer and control groups (27.80 ± 14.45 and 28.29 ± 19.79). SEM images showed a bacteria-free state in the Ca(OH)2 group after 7 days while few bacteria were found in the probiotics supernatants group. An extensive invasion of bacteria was found in poloxamer and controls groups.

CONCLUSION: MSP has a potential antibacterial effect on E. faecalis growth closely similar to the routinely used Ca (OH)2.}, } @article {pmid37080530, year = {2023}, author = {Bijle, MN and Abdalla, MM and Hung, IFN and Yiu, CKY}, title = {The effect of synbiotic-fluoride therapy on multi-species biofilm.}, journal = {Journal of dentistry}, volume = {133}, number = {}, pages = {104523}, doi = {10.1016/j.jdent.2023.104523}, pmid = {37080530}, issn = {1879-176X}, mesh = {Humans ; Fluorides/pharmacology/therapeutic use ; *Synbiotics ; Streptococcus mutans ; Biofilms ; *Dental Caries/prevention & control/microbiology ; Carbohydrates/pharmacology ; }, abstract = {OBJECTIVES: The study objective was to examine the effect of synbiotic-fluoride (SF) therapy within a multi-species cariogenic biofilm model system comprising of S. mutans, S. sanguinis, and S. gordonii.

METHODS: The SF therapy was prepared using 2% L-arginine (Arg), 0.2% NaF and probiotic L. rhamnosus GG (LRG). The 8 treatment groups were: Group 1: No treatment, Group 2: 2% Arg, Group 3: 0.2% NaF, Group 4: LRG, Group 5: 2% Arg+0.2% NaF, Group 6: 2% Arg+LRG, Group 7: 0.2% NaF+LRG, and Group 8: SF therapy (2% Arg+0.2% NaF +LRG). Multi-species biofilm model over 96 h comprising Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii was utilized. The biofilms received cariogenic challenge and SF therapy 2 × /day. The extracellular matrix components were analyzed for carbohydrates, proteins, and extra-cellular DNA (eDNA). The live/dead cells were imaged and quantified using confocal microscopy. The viable/dead bacterial concentrations were estimated using propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR). The gene expressions for gtfB, sagP, arcA, argG, and argH were measured using real-time reverse transcriptase qPCR.

RESULTS: Carbohydrates and protein content with SF therapy were higher than non-LRG containing groups, while eDNA content was lower than other groups (p<0.05). Live bacterial proportions determined using confocal imaging with SF therapy were the lowest (p<0.05). The 2% Arg+LRG and SF therapy showed higher viable L. rhamnosus GG than 0.2% NaF+LRG (p<0.05). The dead S. mutans with SF therapy were higher than the other groups (p<0.05) with no difference from 2% Arg+0.2% NaF and 2% Arg+LRG (p>0.05). The SF therapy significantly downregulates gtfB and upregulates sagP, arcA, argG, argH gene expression (p<0.05).

CONCLUSION: Synbiotic-fluoride therapy effectuates multi-fold changes in the multi-species biofilm matrix and cellular components leading to superior ecological homeostasis than its individual contents, prebiotics (arginine), probiotic (L. rhamnosus GG), and fluorides (NaF).

CLINICAL SIGNIFICANCE: The ecological-based synbiotic-fluoride caries-preventive therapy aids in maintaining biofilm homeostasis to preempt/restore dysbiosis thereby sustaining dynamic-diverse health-associated microbial stability significant as a preventive regimen for high caries-risk patients.}, } @article {pmid37080258, year = {2023}, author = {Huijboom, L and Tempelaars, M and Fan, M and Zhu, Y and Boeren, S and van der Linden, E and Abee, T}, title = {L-tyrosine modulates biofilm formation of Bacillus cereus ATCC 14579.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104072}, doi = {10.1016/j.resmic.2023.104072}, pmid = {37080258}, issn = {1769-7123}, abstract = {Bacillus cereus is a food-borne pathogen capable of producing biofilms. Following analysis of biofilm formation by B. cereus ATCC 14579 transposon mutants in defined medium (DM), a deletion mutant of bc2939 (Δbc2939) was constructed that showed decreased crystal violet biofilm staining and biofilm cell counts. In addition, Δbc2939 also produced smaller colony biofilms with lower cell counts and loss of wrinkly morphology. The bc2939 gene encodes for Prephenate dehydrogenase, which converts Prephenate to 4-Hydroxy-phenylpyruvate (4-HPPA) in the L-tyrosine branch of the Shikimate pathway. While growth of the mutant and WT in DM was similar, addition of L-tyrosine was required to restore WT-like (colony) biofilm formation. Comparative proteomics showed reduced expression of Tyrosine-protein kinase/phosphatase regulators and extracellular polysaccharide cluster 1 (EPS1) proteins, aerobic electron transfer chain cytochrome aa3/d quinol oxidases, and iso-chorismate synthase involved in menaquinone synthesis in DM grown mutant biofilm cells, while multiple oxidative stress-related catalases and superoxide dismutases were upregulated. Performance in shaking cultures showed a 100-fold lower concentration of menaquinone-7 and reduction in cell counts of DM grown Δbc2939 indicating increased oxygen sensitivity. Combining all results, points to an important role of Tyrosine-modulated EPS1 production and menaquinone-dependent aerobic respiration in B. cereus ATCC 14579 (colony) biofilm formation.}, } @article {pmid37080094, year = {2023}, author = {Cattò, C and Mu, A and Moreau, JW and Wang, N and Cappitelli, F and Strugnell, R}, title = {Biofilm colonization of stone materials from an Australian outdoor sculpture: Importance of geometry and exposure.}, journal = {Journal of environmental management}, volume = {339}, number = {}, pages = {117948}, doi = {10.1016/j.jenvman.2023.117948}, pmid = {37080094}, issn = {1095-8630}, mesh = {Australia ; *Biofilms ; *Cyanobacteria/genetics ; RNA, Ribosomal, 16S/genetics ; Sculpture ; }, abstract = {The safeguarding of Australian outdoor stone heritage is currently limited by a lack of information concerning mechanisms responsible for the degradation of the built heritage. In this study, the bacterial community colonizing the stone surface of an outdoor sculpture located at the Church of St. John the Evangelist in Melbourne was analysed, providing an overview of the patterns of microbial composition associated with stone in an anthropogenic context. Illumina MiSeq 16S rRNA gene sequencing together with confocal laser microscope investigations highlighted the bacterial community was composed of both phototrophic and chemotrophic microorganisms characteristic of stone and soil, and typical of arid, salty and urban environments. Cardinal exposure, position and surface geometry were the most important factors in determining the structure of the microbial community. The North-West exposed areas on the top of the sculpture with high light exposure gave back the highest number of sequences and were dominated by Cyanobacteria. The South and West facing in middle and lower parts of the sculpture received significantly lower levels of radiation and were dominated by Actinobacteria. Proteobacteria were observed as widespread on the sculpture. This pioneer research provided an in-depth investigation of the microbial community structure on a deteriorated artistic stone in the Australian continent and provides information for the identification of deterioration-associated microorganisms and/or bacteria beneficial for stone preservation.}, } @article {pmid37079063, year = {2023}, author = {Wang, H and Ge, Q and Shao, X and Wei, Y and Zhang, X and Wang, H and Xu, F}, title = {Influences of flavonoids from Sedum aizoon L. on biofilm formation of Pseudomonas fragi.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {11}, pages = {3687-3697}, pmid = {37079063}, issn = {1432-0614}, support = {LY16C200003//Natural Science Foundation of Zhejiang Province/ ; }, mesh = {*Pseudomonas fragi/genetics/metabolism ; *Sedum ; Flavonoids/pharmacology/metabolism ; Flagellin ; Biofilms ; }, abstract = {Pseudomonas fragi (P. fragi) is one of the main categories of bacteria responsible for the spoilage of chilled meat. In the processing and preservation of chilled meat, it is easy to form biofilms on the meat, leading to the development of slime on the meat, which becomes a major quality defect. Flavonoids, as one of the critical components of secondary plant metabolites, are receiving increasing attention for their antibacterial activity. Flavonoids in Sedum aizoon L. (FSAL), relying on its prominent antibacterial activity, are of research importance in food preservation and other applications. This article aims to investigate the effect of FSAL on the biofilm formation of P. fragi, to better apply FSAL to the processing and preservation of meat products. The disruption of cellular structure and aggregation properties by FSAL was demonstrated by the observation of the cellular state within the biofilm. The amount of biofilm formation was determined by crystal violet staining, and the content of polysaccharides and proteins in the extracellular wrapped material was determined. It was shown that the experimental concentrations of FSAL (1.0 MIC) was able to inhibit biofilm formation and reduce the main components in the extracellular secretion. The swimming motility assay and the downregulation of flagellin-related genes confirmed that FSAL reduced cell motility and adhesion. The downregulation of cell division genes and the lowering of bacterial metabolic activity suggested that FSAL could hinder bacterial growth and reproduction within P. fragi biofilms. KEY POINTS: • FSAL inhibited the activity of Pseudomonas fragi in the dominant meat strain • The absence of EPS components affected the formation of P. fragi biofilms • P. fragi has reduced adhesion capacity due to impaired flagellin function.}, } @article {pmid37079062, year = {2023}, author = {Elfaky, MA and Elbaramawi, SS and Eissa, AG and Ibrahim, TS and Khafagy, ES and Ali, MAM and Hegazy, WAH}, title = {Drug repositioning: doxazosin attenuates the virulence factors and biofilm formation in Gram-negative bacteria.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {11}, pages = {3763-3778}, pmid = {37079062}, issn = {1432-0614}, support = {IFPIP:1623-166-1443//King Abdulaziz University/ ; }, mesh = {Mice ; Animals ; *Virulence Factors/metabolism ; *Biofilms ; Doxazosin/pharmacology ; Drug Repositioning ; Quorum Sensing ; Anti-Bacterial Agents/pharmacology/metabolism ; Pseudomonas aeruginosa/metabolism ; }, abstract = {The resistance development is an increasing global health risk that needs innovative solutions. Repurposing drugs to serve as anti-virulence agents is suggested as an advantageous strategy to diminish bacterial resistance development. Bacterial virulence is controlled by quorum sensing (QS) system that orchestrates the expression of biofilm formation, motility, and virulence factors production as enzymes and virulent pigments. Interfering with QS could lead to bacterial virulence mitigation without affecting bacterial growth that does not result in bacterial resistance development. This study investigated the probable anti-virulence and anti-QS activities of α-adrenoreceptor blocker doxazosin against Proteus mirabilis and Pseudomonas aeruginosa. Besides in silico study, in vitro and in vivo investigations were conducted to assess the doxazosin anti-virulence actions. Doxazosin significantly diminished the biofilm formation and release of QS-controlled Chromobacterium violaceum pigment and virulence factors in P. aeruginosa and P. mirabilis, and downregulated the QS encoding genes in P. aeruginosa. Virtually, doxazosin interfered with QS proteins, and in vivo protected mice against P. mirabilis and P. aeruginosa. The role of the membranal sensors as QseC and PmrA was recognized in enhancing the Gram-negative virulence. Doxazosin downregulated the membranal sensors PmR and QseC encoding genes and could in silico interfere with them. In conclusion, this study preliminary documents the probable anti-QS and anti-virulence activities of doxazosin, which indicate its possible application as an alternative or in addition to antibiotics. However, extended toxicological and pharmacological investigations are essential to approve the feasible clinical application of doxazosin as novel efficient anti-virulence agent. KEY POINTS: • Anti-hypertensive doxazosin acquires anti-quorum sensing activities • Doxazosin diminishes the virulence of Proteus mirabilis and Pseudomonas aeruginosa • Doxazosin could dimmish the bacterial espionage.}, } @article {pmid37078875, year = {2023}, author = {Palau, M and Muñoz, E and Gusta, MF and Larrosa, N and Gomis, X and Gilabert, J and Almirante, B and Puntes, V and Texidó, R and Gavaldà, J}, title = {In Vitro Antibacterial Activity of Silver Nanoparticles Conjugated with Amikacin and Combined with Hyperthermia against Drug-Resistant and Biofilm-Producing Strains.}, journal = {Microbiology spectrum}, volume = {11}, number = {3}, pages = {e0028023}, pmid = {37078875}, issn = {2165-0497}, support = {//Spanish Network for the Research in Infectious Disease/ ; 472/U/2018//Fundació la Marató de TV3 (Fundació la Marató)/ ; 01162//MEC | Instituto de Salud Carlos III (ISCIII)/ ; }, mesh = {Amikacin/pharmacology ; Silver/pharmacology/chemistry ; *Metal Nanoparticles/chemistry ; Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; *Hyperthermia, Induced ; }, abstract = {In view of the current increase and spread of antimicrobial resistance (AMR), there is an urgent need to find new strategies to combat it. This study had two aims. First, we synthesized highly monodispersed silver nanoparticles (AgNPs) of approximately 17 nm, and we functionalized them with mercaptopoly(ethylene glycol) carboxylic acid (mPEG-COOH) and amikacin (AK). Second, we evaluated the antibacterial activity of this treatment (AgNPs_mPEG_AK) alone and in combination with hyperthermia against planktonic and biofilm-growing strains. AgNPs, AgNPs_mPEG, and AgNPs_mPEG_AK were characterized using a suite of spectroscopy and microscopy methods. Susceptibility to these treatments and AK was determined after 24 h and over time against 12 clinical multidrug-resistant (MDR)/extensively drug-resistant (XDR) isolates of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The efficacy of the treatments alone and in combination with hyperthermia (1, 2, and 3 pulses at 41°C to 42°C for 15 min) was tested against the same planktonic strains using quantitative culture and against one P. aeruginosa strain growing on silicone disks using confocal laser scanning microscopy. The susceptibility studies showed that AgNPs_mPEG_AK was 10-fold more effective than AK alone, and bactericidal efficacy after 4, 8, 24, or 48 h was observed against 100% of the tested strains. The combination of AgNPs_mPEG_AK and hyperthermia eradicated 75% of the planktonic strains and exhibited significant reductions in biofilm formation by P. aeruginosa in comparison with the other treatments tested, except for AgNPs_mPEG_AK without hyperthermia. In conclusion, the combination of AgNPs_mPEG_AK and hyperthermia may be a promising therapy against MDR/XDR and biofilm-producing strains. IMPORTANCE Antimicrobial resistance (AMR) is one of the greatest public health challenges, accounting for 1.27 million deaths worldwide in 2019. Biofilms, a complex microbial community, directly contribute to increased AMR. Therefore, new strategies are urgently required to combat infections caused by AMR and biofilm-producing strains. Silver nanoparticles (AgNPs) exhibit antimicrobial activity and can be functionalized with antibiotics. Although AgNPs are very promising, their effectiveness in complex biological environments still falls below the concentrations at which AgNPs are stable in terms of aggregation. Thus, improving the antibacterial effectiveness of AgNPs by functionalizing them with antibiotics may be a significant change to consolidate AgNPs as an alternative to antibiotics. It has been reported that hyperthermia has a large effect on the growth of planktonic and biofilm-producing strains. Therefore, we propose a new strategy based on AgNPs functionalized with amikacin and combined with hyperthermia (41°C to 42°C) to treat AMR and biofilm-related infections.}, } @article {pmid37077927, year = {2023}, author = {Marshall-Hudson, A and Tuley, M and Damstra, M and Dosik, JS and Myntti, MF and Porral, D and Palomo, J}, title = {A 6-month, Multi-center, Double-blind, Controlled Study to Evaluate the Effect of a Biofilm Disrupting Acne Cream on Mild-to-Moderate Facial Acne in Female Volunteer Subjects.}, journal = {The Journal of clinical and aesthetic dermatology}, volume = {16}, number = {4}, pages = {43-52}, pmid = {37077927}, issn = {1941-2789}, abstract = {OBJECTIVES: The primary aim of this study was to assess the change in acne lesions and severity within all treatment groups over the course of a six-month study.

METHODS: This was a six-month, multisite, randomized, double-blind, controlled study in female subjects with mild-to-moderate acne to assess the clinical and psychological outcomes of treatment with biofilm disrupting acne cream 2x, biofilm disrupting acne cream 1x, biofilm disrupting acne cream without salicylic acid, 2.5% benzoyl peroxide (BPO) gel, and placebo. Subjects applied the assigned product to their face twice daily and were evaluated for clinical acne and quality of life outcomes at baseline and after six, 12, 18, and 24 weeks of treatment.

RESULTS: After 24 weeks of use, subjects treated with biofilm disrupting acne cream 2x had a significantly greater improvement in the Investigator Global Assessment (IGA), compared to those treated with 2.5% BPO gel. Based on dermatologic assessments, biofilm disrupting acne cream 2x, biofilm disrupting acne cream 1x, biofilm disrupting acne cream without salicylic acid, and placebo control were associated with less erythema and dryness, compared to 2.5% BPO gel.

LIMITATIONS: Assessments within this study had the potential for subjective differences due to variability between evaluators.

CONCLUCION: Biofilm disrupting acne cream 2x and biofilm disrupting acne cream 1x provided equivalent efficacy to 2.5% BPO gel with less of the adverse effects commonly associated with BPO, such as erythema and dryness. Both the biofilm disrupting acne cream without salicylic acid and the placebo control were associated with mild improvements to acne symptoms over the course of the 24-week study.

TRIAL REGISTRY INFORMATION: ClinicalTrials.gov, NCT03106766.}, } @article {pmid37077117, year = {2023}, author = {Namazoğlu, B and Aksoy, M and Memiş-Özgül, B and Tulga-Öz, F}, title = {Anti-microbial efficiency of gaseous ozone's combined use with fluoride and chlorhexidine on time-related oral biofilm: an in situ study on pediatric patients.}, journal = {Medical gas research}, volume = {13}, number = {4}, pages = {192-197}, pmid = {37077117}, issn = {2045-9912}, mesh = {Male ; Female ; Humans ; Animals ; Cattle ; Child ; Chlorhexidine/pharmacology ; *Anti-Infective Agents, Local/pharmacology ; Fluorides/pharmacology ; *Ozone/pharmacology ; Biofilms ; }, abstract = {Oral biofilm formation is the main reason for both caries progression and soft tissue diseases. Preventing the formation and promotion of biofilm has been known as the first attempt to prevent the development of caries and soft tissue problems in the oral cavity. The present study aimed to assess the effect of ozone and its combined use with chlorhexidine (CHX) and fluoride on the complex biofilm formation of pediatric patients under in situ conditions. Extracted bovine teeth were sterilized and cut into 2 × 3 mm[2] sections. The samples were placed in removable maxillary plates and 10 healthy individuals (6 boys, 4 girls; aged 7-14 years) were asked to wear these plates for 6, 24 and 48 hours. Afterwards, the tooth samples were removed, and anti-plaque agents were applied to the time-related plaque formation. Plaque thickness and viable bacterial percentages were detected by confocal laser scanning microscopy. All materials used in the study decreased the plaque formation and the percentage of viable microorganisms compared with the control group (physiological saline). In 6- and 24-hour biofilm evaluations, ozone-CHX was the most effective group in decreasing the plaque thickness (P > 0.05). Ozone-CHX and Ozone-Fluoride groups were found to be better in 48-hour biofilm assessments in caries-free group (P > 0.05). Ozone-CHX group showed a better inhibitory effect on the viability of microorganisms in 6-, 24- and 48-hour biofilm formations (P < 0.05). Although CHX has been known as the gold standard for inhibiting the oral biofilm formation, according to the results of the study, gaseous ozone and its combined use with CHX have shown better results in reducing the biofilm thickness and viable bacterial percentages of in situ formed time-related biofilm formation in pediatric patients. The use of gaseous ozone can be preferred in clinical conditions in pediatric patients instead of the CHX agents.}, } @article {pmid37076397, year = {2023}, author = {Scavone, P and Iribarnegaray, V and González, MJ and Navarro, N and Caneles-Huerta, N and Jara-Wilde, J and Härtel, S and Zunino, P}, title = {Role of Proteus mirabilis flagella in biofilm formation.}, journal = {Revista Argentina de microbiologia}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ram.2023.01.005}, pmid = {37076397}, issn = {0325-7541}, abstract = {Proteus mirabilis(P. mirabilis) is a common etiological agent of urinary tract infections, particularly those associated with catheterization. P. mirabilis efficiently forms biofilms on different surfaces and shows a multicellular behavior called 'swarming', mediated by flagella. To date, the role of flagella in P. mirabilis biofilm formation has been under debate. In this study, we assessed the role of P. mirabilis flagella in biofilm formation using an isogenic allelic replacement mutant unable to express flagellin. Different approaches were used, such as the evaluation of cell surface hydrophobicity, bacterial motility and migration across catheter sections, measurements of biofilm biomass and biofilm dynamics by immunofluorescence and confocal microscopy in static and flow models. Our findings indicate that P. mirabilis flagella play a role in biofilm formation, although their lack does not completely avoid biofilm generation. Our data suggest that impairment of flagellar function can contribute to biofilm prevention in the context of strategies focused on particular bacterial targets.}, } @article {pmid37076015, year = {2023}, author = {Zhou, Q and Wang, T and Li, K and Zhang, S and Wang, K and Hong, W and Liu, R and Li, P}, title = {Biofilm microenvironment-responsive polymeric CO releasing micelles for enhanced amikacin efficacy.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {357}, number = {}, pages = {561-571}, doi = {10.1016/j.jconrel.2023.04.025}, pmid = {37076015}, issn = {1873-4995}, mesh = {*Micelles ; *Amikacin ; Polymers/chemistry ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Carriers/chemistry ; }, abstract = {Biofilm-associated infections (BAI) have posed serious threats to public health. Novel therapy based on carbon monoxide (CO) is being increasingly appreciated. However, CO therapy like inhaled gas treatment was impeded owing to its low bioavailability. Besides, the direct use of CO releasing molecules (CORM) showed low therapeutic efficacy in BAI. Therefore, it is vital to improve the efficiency of CO therapy. Herein, we proposed polymeric CO releasing micelles (pCORM) from self-assembly of amphiphilic copolymers containing CORM bearing block as hydrophobic part and acryloylmorpholine block as hydrophilic part. The catechol modified CORM were conjugated through pH cleavable boronate ester bonds and releasing CO passively under biofilm microenvironment. When combined with subminimal inhibitory concentration antibiotic amikacin, pCORM could significantly enhance its bactericidal efficiency against biofilm-encapsulated multidrug-resistant bacteria, representing a promising approach to combat BAI.}, } @article {pmid37075926, year = {2023}, author = {Tatta, ER and Paul, S and Kumavath, R}, title = {Transcriptome analysis revealed the synergism of novel rhodethrin inhibition on biofilm architecture, antibiotic resistance and quorum sensing inEnterococcus faecalis.}, journal = {Gene}, volume = {871}, number = {}, pages = {147436}, doi = {10.1016/j.gene.2023.147436}, pmid = {37075926}, issn = {1879-0038}, mesh = {*Quorum Sensing/genetics ; *Biofilms ; Gene Expression Profiling ; Drug Resistance, Bacterial/genetics ; Enterococcus faecalis/genetics ; Chloramphenicol/metabolism/pharmacology ; Bacterial Proteins/metabolism ; }, abstract = {Enterococcus sp. emerged as an opportunistic nosocomial pathogen with the highest antibiotic resistance and mortality rate. Biofilm is problematic primarily since it is regulated by the global bacterial cell to cell communication mediated by the quorum sensing signaling system. Thus, potential natural antagonists in a novel drug formulation against biofilm-forming Enterococcus faecalis is critical. We used RNA-Seq to evaluate the effects of the novel molecule rhodethrin with chloramphenicol induced on Enterococcus faecalis and DEGs were identified. In transcriptome sequence analysis, a total of 448 with control Vs rhodethrin, 1591 were in control Vs chloramphenicol, 379 genes were DEGs from control Vs synergies, in rhodethrin with chloramphenicol, 379 genes were differentially expressed, whereas 264 genes were significantly downregulated, indicating that 69.69% ofE. faecaliswas altered. The transcriptional sequence data further expression analysis qRT-PCR, and the results shed that the expression profiles of five significant biofilm formation responsible genes such as, Ace, AtpB, lepA, bopD, and typA, 3 genes involved in quorum sensing are sylA, fsrC and camE, and 4 genes involved in resistance were among including liaX, typA, EfrA, and lepA, were significantly suppressed expressions of the biofilm, quorum sensing, and resistance that are supported by transcriptome analysis.}, } @article {pmid37074383, year = {2023}, author = {Chen, X and Xiao, L and Niu, J and Wang, Y and Zhang, X and Gong, L and Yao, F and Xu, K}, title = {Early succession of biofilm bacterial communities in newly built drinking water pipelines via multi-area analysis.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {11}, pages = {3817-3828}, pmid = {37074383}, issn = {1432-0614}, support = {52000032//National Natural Science Foundation of China/ ; GY-H-21258//Fuzhou Water Supply Co., Ltd. and Fuzhou Water Quality Monitoring Co., Ltd./ ; GY-Z17075//Fujian University of Technology/ ; 2019-JJFDKY-07//Jinjiang Fuzhou University Science Park/ ; }, mesh = {*Water Supply ; *Drinking Water ; Bacteria ; Biofilms ; Iron ; Water Microbiology ; }, abstract = {Biofilms inhabiting pipeline walls are critical to drinking water quality and safety. With massive pipeline replacement underway, however, biofilm formation process in newly built pipes and its effects on water quality are unclear. Moreover, differences and connections between biofilms in newly built and old pipes are unknown. In this study, early succession (≤ 120 days) of biofilm bacterial communities (abundance and diversity) in upper, middle and bottom areas of a newly built cement-lined ductile iron pipeline were evaluated using improved Propella™ biofilm reactor and multi-area analysis. A comparison with old pipelines (grey cast iron, 10 years) was performed. In the newly built pipeline, the abundance of biofilm bacteria did not change significantly between 40 and 80 days, but increased significantly between 80 and 120 days. The biofilm bacterial abundance (per unit area) in the bottom area was always higher than that in the upper and middle areas. Based on alpha diversity index and PCoA results, biofilm bacterial community richness, diversity and composition did not change significantly during the 120-day operation. Besides, biofilm shedding from the walls of newly built pipeline significantly increased bacterial abundance in the outlet water. Opportunistic pathogen-containing genera, such as Burkholderia, Acinetobacter and Legionella, were identified in both water and biofilm samples from newly built pipelines. The comparison between new and old pipelines suggested a higher bacterial abundance per unit area at the middle and bottom areas in old pipelines. Moreover, the bacterial community composition of biofilms in old pipelines was similar to that of newly built pipelines. These results contribute to accurate prediction and management of biofilm microbial communities in drinking water pipelines, ensuring the biosafety of drinking water. KEY POINTS: • Biofilm bacterial communities in different areas of pipe wall were revealed. • The abundance of biofilm bacteria increased significantly between 80 and 120 days. • Biofilm bacterial community compositions of newly built and old pipes were similar.}, } @article {pmid37073912, year = {2022}, author = {Goutham, PAJ and Kalaiselvam, R and Ganesh, A and C, BP}, title = {Antibacterial Efficacy of Irrigants with Varying Osmolarity on E. faecalis Biofilm: An In Vitro Study.}, journal = {The journal of contemporary dental practice}, volume = {23}, number = {10}, pages = {998-1003}, doi = {10.5005/jp-journals-10024-3417}, pmid = {37073912}, issn = {1526-3711}, mesh = {*Sodium Chloride/pharmacology ; *Root Canal Irrigants/pharmacology ; Chlorhexidine/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Enterococcus faecalis ; Sodium Hypochlorite/pharmacology ; Dental Pulp Cavity/microbiology ; }, abstract = {AIM: To evaluate the role of the addition of different concentrations of sodium chloride salt to conventional intracanal irrigants to vary their osmotic values and thereby compare their antibacterial efficacy.

MATERIALS AND METHODS: In an active attachment biofilm model, Enterococcus faecalis (ATCC 29212) biofilms were grown. Sodium chloride salts were added to 100 mL of distilled water to make 6M (hyperosmotic), 0.5M, and 0.25M (hypoosmotic) sodium chloride solutions, respectively. The experimental groups were divided into three groups: Group I: 5.25% sodium hypochlorite, group II: 2% chlorhexidine, and group III: 2% povidone iodine, and four subgroups within these three groups, such as subgroup A (without salt solution), subgroup B (with 6M of hyperosmotic salt solution), subgroup C (with 0.5M of hypoosmotic salt solution), and subgroup D (with 0.25M of hypoosmotic salt solution), respectively. Biofilms were treated with all the subgroups for a contact time of 15 min. A crystal violet assay was done to estimate the bacterial cell biomass.

RESULTS: The results revealed that subgroups IIIB, IB, and IID, ID had a statistical reduction in bacterial biomass at p < 0.05. There were no significant differences between subgroups IC, IIC, and IIIC and subgroups IA, IIA, and IIIA.

CONCLUSION: The antibacterial efficacy of all three irrigants was significantly affected by varying the osmolarities.

CLINICAL SIGNIFICANCE: The results prove that the hyperosmotic and hypoosmotic salt solutions, along with irrigants, have enhanced antibacterial efficacy on E. faecalis biofilm due to its ability to vary the turgor pressure of cell wall, as well as the inherent properties of the irrigants such as hypochlorous acid formation, ionic interaction, and free radical interactions.}, } @article {pmid37073093, year = {2023}, author = {Kıvanç, SA and Akova, B and Kıvanç, M}, title = {Effects of the Dibenzofuran, Usnic Acid, on Inhibition of Ocular Biofilm Formation Due to Coagulase-Negative Staphylococci.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {29}, number = {}, pages = {e940266}, pmid = {37073093}, issn = {1643-3750}, mesh = {Humans ; *Coagulase/pharmacology ; *Staphylococcal Infections/microbiology ; Anti-Bacterial Agents/pharmacology ; Dibenzofurans/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND Coagulase-negative staphylococci (CoNS) are gram-positive, aerobic, commensal bacteria found on the skin and mucus membranes, including the conjunctiva. Usnic acid (UA) is a dibenzofuran derivative isolated from lichens. This study aimed to investigate the effects of usnic acid on inhibition of ocular biofilm formation due to CoNS. MATERIAL AND METHODS Nine Staphylococcus epidermidis isolates, 5 Staphylococcus hominis isolates, 2 Staphylococcus saprophyticus isolates, and 1 Staphylococcus capitis and Staphylococcus lentus isolates were taken as test bacteria. They were inoculated into brain heart infusion broth and incubated for 24 hours at 35°C and activated. Antibiotic susceptibility was investigated by Kirby-Bauer disc diffusion method. Biofilm production was determined using the microtiter plate method and optical densitometry was measured at 570 nm using an automated microplate reader. Anti-biofilm activity of UA was determined by microtitration method and biofilm removal percentage was calculated. RESULTS All tested bacteria were found as high biofilm-producer strains; they were generally resistant to methicillin, but susceptible to vancomycin. UA inhibited the biofilm formation of S. epidermidis isolates, ranging from 5.7% to 81.5%. It inhibited the biofilm formation of S. saprophyticus and S. lentus by 73.3% and 74.3%, respectively. There was no effect of UA on mature biofilms of S. epidermidis 17.7H, S. epidermidis 15.41, S. hominis 9.3, S. hominis 17.2H, S. saprophyticus, and S. lentus. CONCLUSIONS It was determined that UA exerted anti-biofilm activity on some CoNS isolated from the ocular surface. Anti-biofilm activity was found to be higher even in strains that did not show antibacterial activity.}, } @article {pmid37071524, year = {2023}, author = {Esfahani, MB and Khodavandi, A and Alizadeh, F and Bahador, N}, title = {Antibacterial and Anti-Biofilm Activities of Microbial Synthesized Silver and Magnetic Iron Oxide Nanoparticles against Pseudomonas aeruginosa.}, journal = {IEEE transactions on nanobioscience}, volume = {PP}, number = {}, pages = {}, doi = {10.1109/TNB.2023.3268138}, pmid = {37071524}, issn = {1558-2639}, abstract = {Pseudomonas aeruginosa is a human bacterial pathogen causing devastating diseases and equipped with various virulence factors like biofilm formation. Common antibiotic treatment has limited efficacy for the P. aeruginosa present in biofilms because of the increased resistance. In this study, we focused our attention on the antibacterial and anti-biofilm activities of various microbial synthesized silver (nano-Ag) and magnetic iron oxide (nano-Fe3O4) nanoparticles against clinical isolates of P. aeruginosa that displayed ceftazidime resistance. The nano-Ag and nano-Fe3O4 represented great antibacterial properties. Nano-Ag and nano-Fe3O4 exhibited a reduction in the biofilm formation by P. aeruginosa reference strain as determined by crystal violet and XTT assays and light microscopy method. Among all, nano-Ag-2 and 7 owing to inherent attributes and mechanisms of resistance in the bacterial biofilm, exhibited anti-biofilm efficacy against ceftazidime resistance clinical isolate of P. aeruginosa. Moreover, nano-Ag and nano-Fe3O4 changed the relative expression of biofilm-associated genes, PELA and PSLA in a concentration dependent manner by P. aeruginosa reference strain. As revealed by qRT-PCR, the expression levels of biofilm-associated genes were downregulated in P. aeruginosa biofilms treated with nano-Ag, while selected biofilm-associated genes were low expressed under treated with nano-Fe3O4. Results of the study demonstrate the potential of microbial synthesized nano-Ag-2 and 7 to act as anti-biofilm agents against ceftazidime resistance clinical isolate of P. aeruginosa. Molecular targeting of biofilm-associated genes by nano-Ag and nano-Fe3O4 may be candidate for new therapeutics against P. aeruginosa diseases.}, } @article {pmid37070220, year = {2023}, author = {Chen, Q and Zhang, X and Wang, Q and Yang, J and Zhong, Q}, title = {The mixed biofilm formed by Listeria monocytogenes and other bacteria: Formation, interaction and control strategies.}, journal = {Critical reviews in food science and nutrition}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/10408398.2023.2200861}, pmid = {37070220}, issn = {1549-7852}, abstract = {Listeria monocytogenes is an important foodborne pathogen. It can adhere to food or food contact surface for a long time and form biofilm, which will lead to equipment damage, food deterioration, and even human diseases. As the main form of bacteria to survive, the mixed biofilms often exhibit higher resistance to disinfectants and antibiotics, including the mixed biofilms formed by L. monocytogenes and other bacteria. However, the structure and interspecific interaction of the mixed biofilms are very complex. It remains to be explored what role the mixed biofilm could play in the food industry. In this review, we summarized the formation and influence factors of the mixed biofilm developed by L. monocytogenes and other bacteria, as well as the interspecific interactions and the novel control measures in recent years. Moreover, the future control strategies are prospected, in order to provide theoretical basis and reference for the research of the mixed biofilms and the targeted control measures.}, } @article {pmid37070126, year = {2023}, author = {Pei, ZJ and Li, C and Dai, W and Lou, Z and Sun, X and Wang, H and Khan, AA and Wan, C}, title = {The Anti-Biofilm Activity and Mechanism of Apigenin-7-O-Glucoside Against Staphylococcus aureus and Escherichia coli.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {2129-2140}, pmid = {37070126}, issn = {1178-6973}, abstract = {INTRODUCTION: This study aimed to examine the anti-biofilm activity and mechanism of gallic acid (GA), kaempferol-7-O-glucoside (K7G) and apigenin-7-O-glucoside (A7G) against Staphylococcus aureus and Escherichia coli.

METHODS: The antibacterial activity of the natural compounds was determined by serial dilution method. The inhibitory activity of natural compounds on biofilms was determined by crystal violet staining method. The effects and mechanisms of natural compounds on bacterial biofilms were analyzed by atomic force microscopy.

RESULTS: In our study, compared with GA and K7G, A7G was found to exhibit the strongest anti-biofilm and antibacterial activities. The minimum biofilm inhibitory concentration (MBIC) of A7G against S. aureus and E. coli was 0.20 mg/mL and 0.10 mg/mL, respectively. The inhibition rates of 1/2 MIC of A7G on biofilms of S. aureus and E. coli were 88.9%, and 83.2% respectively. Moreover, atomic force microscope (AFM) images showed the three-dimensional biofilm morphology of S. aureus and E. coli, and the results indicated that A7G was highly effective in biofilm inhibition.

DISCUSSION: It was found that the inhibition of A7G on biofilm was achieved through inhibiting on exopolysaccharides (EPS), quorum sensing (QS), and cell surface hydrophobicity (CSH). A7G exerted strong anti-biofilm activities by inhibiting EPS production, QS, and CSH. Hence, A7G, as a natural substance, could be a promising novel antibacterial and anti-biofilm agent for control of biofilm in food industry.}, } @article {pmid37069901, year = {2023}, author = {Naisi, S and Bayat, M and Zahraei Salehi, T and Rahimian Zarif, B and Yahyaraeyat, R}, title = {Antimicrobial and anti-biofilm effects of carotenoid pigment extracted from Rhodotorula glutinis strain on food-borne bacteria.}, journal = {Iranian journal of microbiology}, volume = {15}, number = {1}, pages = {79-88}, pmid = {37069901}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Carotenoid pigments are among the most important pigments and have many applications in various food, cosmetics, hygiene industries and biotechnology. These pigments are produced by plants and microorganisms including Rhodotorula spp. This research intended to study the antimicrobial and antibiofilm effects of the carotenoid pigment from Rhodotorula glutinis on food spoilage bacteria (Staphylococcus aureus and Salmonella Typhimurium).

MATERIALS AND METHODS: The R. glutinis was isolated from milk samples of cows with mastitis and ITS sequence-based typing was performed on them. After extracting the pigment from R. glutinis, its purity was examined using thin-layer chromatography. Following that, the broth microdilution method was used to evaluate antimicrobial effects of the pigment and MtP assay and subsequently scanning electron microscopy were used to assess the antibiofilm effects. In addition, the sub-MIC effects of the pigment on expression of quorum-sensing (QS) genes in S. Typhimurium isolates (sdiA and luxS) and S. aureus isolates (hld) were studied. Finally, the degree of toxicity of the pigment was analyzed using the MTT assay.

RESULTS: ITS sequence analysis of R. glutinis revealed that the recently separated isolates exhibited strong differences with the strains recorded in NCBI database in genetic structure. The pigment produced by R. glutinis had strong antimicrobial effects and its mean MIC against S. Typhimurium isolates (17.0 μl.ml[-1]) was higher than the mean MIC against the S. aureus isolates (4.1 μl.ml[-1]). Electron microscope images and real-time observations indicated that the sub-MIC values of the pigment suppressed biofilm formation by suppressing expression of QS genes. In addition, the mentioned pigment at high MIC concentrations did not have toxic effects on Vero cells.

CONCLUSION: This research suggests that R. glutinis pigment is effective in destroying the planktonic form of food spoilage bacteria and degrading food spoilage biofilm-forming bacteria. Moreover, considering the low toxicity level of R. glutinis pigment for eukaryotic cells, we can suggest its use as a natural antibacterial preservative in various food materials.}, } @article {pmid37066293, year = {2023}, author = {Huang, Y and Liu, Y and Pandey, N and Shah, S and Simon-Soro, A and Hsu, J and Ren, Z and Xiang, Z and Kim, D and Ito, T and Oh, MJ and Buckley, C and Alawi, F and Li, Y and Smeets, P and Boyer, S and Zhao, X and Joester, D and Zero, D and Cormode, D and Koo, H}, title = {Iron oxide nanozymes stabilize stannous fluoride for targeted biofilm killing and synergistic oral disease prevention.}, journal = {Research square}, volume = {}, number = {}, pages = {}, pmid = {37066293}, abstract = {Dental caries (tooth decay) is the most prevalent human disease caused by oral biofilms, affecting nearly half of the global population despite increased use of fluoride, the mainstay anticaries (tooth-enamel protective) agent. Recently, an FDA-approved iron oxide nanozyme formulation (ferumoxytol, Fer) has been shown to disrupt caries-causing biofilms with high specificity via catalytic activation of hydrogen peroxide, but it is incapable of interfering with enamel acid demineralization. Here, we find notable synergy when Fer is combined with stannous fluoride (SnF 2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, our data show that SnF 2 enhances the catalytic activity of Fer, significantly increasing reactive oxygen species (ROS) generation and antibiofilm activity. We discover that the stability of SnF 2 (unstable in water) is markedly enhanced when mixed with Fer in aqueous solutions without any additives. Further analyses reveal that Sn [2+] is bound by carboxylate groups in the carboxymethyl-dextran coating of Fer, thus stabilizing SnF 2 and boosting the catalytic activity. Notably, Fer in combination with SnF 2 is exceptionally effective in controlling dental caries in vivo , preventing enamel demineralization and cavitation altogether without adverse effects on the host tissues or causing changes in the oral microbiome diversity. The efficacy of SnF 2 is also enhanced when combined with Fer, showing comparable therapeutic effects at four times lower fluoride concentration. Enamel ultrastructure examination shows that fluoride, iron, and tin are detected in the outer layers of the enamel forming a polyion-rich film, indicating co-delivery onto the tooth surface. Overall, our results reveal a unique therapeutic synergism using approved agents that target complementary biological and physicochemical traits, while providing facile SnF 2 stabilization, to prevent a widespread oral disease more effectively with reduced fluoride exposure.}, } @article {pmid37064802, year = {2023}, author = {Ma, H and Tang, Y and Rong, F and Wang, K and Wang, T and Li, P}, title = {Surface charge adaptive nitric oxide nanogenerator for enhanced photothermal eradication of drug-resistant biofilm infections.}, journal = {Bioactive materials}, volume = {27}, number = {}, pages = {154-167}, pmid = {37064802}, issn = {2452-199X}, abstract = {Due to protection of extracellular polymeric substances, the therapeutic efficiency of conventional antimicrobial agents is often impeded by their poor infiltration and accumulation in biofilm. Herein, one type of surface charge adaptable nitric oxide (NO) nanogenerator was developed for biofilm permeation, retention and eradication. This nanogenerator (PDG@Au-NO/PBAM) is composed of a core-shell structure: thermo-sensitive NO donor conjugated AuNPs on cationic poly(dopamine-co-glucosamine) nanoparticle (PDG@Au-NO) served as core, and anionic phenylboronic acid-acryloylmorpholine (PBAM) copolymer was employed as a shell. The NO nanogenerator featured long circulation and good biocompatibility. Once the nanogenerator reached acidic biofilm, its surface charge would be switched to positive after shell dissociation and cationic core exposure, which was conducive for the nanogenerator to infiltrate and accumulate in the depth of biofilm. In addition, the nanogenerator could sustainably generate NO to disturb the integrity of biofilm at physiological temperature, then generate hyperthermia and explosive NO release upon NIR irradiation to efficiently eradicate drug-resistant bacteria biofilm. Such rational design offers a promising approach for developing nanosystems against biofilm-associated infections.}, } @article {pmid37064519, year = {2023}, author = {Maggio, F and Serio, A and Rossi, C and Purgatorio, C and Buccioni, F and Chaves-López, C and Paparella, A}, title = {Effectiveness of essential oils against dual-species biofilm of Listeria monocytogenes and Pseudomonas fluorescens in a Ricotta-based model system.}, journal = {Italian journal of food safety}, volume = {12}, number = {1}, pages = {11048}, pmid = {37064519}, issn = {2239-7132}, abstract = {Biofilms represent an evolutionary form of life, which translates from life in free-living cells to a community lifestyle. In natural habitats, biofilms are a multispecies complex, where synergies or antagonisms can be established. For example, Listeria monocytogenes and Pseudomonas fluorescens are associated with a dual-species biofilm that is widespread in dairy plants. In food plants, multiple strategies are devised to control biofilms, including natural compounds such as essential oils (EOs). In this respect, this study evaluated the effectiveness of Thymbra capitata (L.) Cav. (TEO) and Cinnamomum zeylanicum (CEO) against a dual-species biofilm of L. monocytogenes and P. fluorescens, mimicking dairy process conditions. Based on Minimum Inhibitory Concentrations results, the EOs concentration (10 μL/mL) was chosen for the antibiofilm assay at 12°C on polystyrene (PS), and stainless-steel surfaces for 168 h, using a Ricotta-based model system as culture medium. Biofilm biomass was assessed by crystal violet staining, and the planktonic and sessile cells were quantified in terms of Log CFU/cm[2]. Results showed that CEO displayed the greatest antibiofilm activity, reducing significantly (P<0.05) P. fluorescens and L. monocytogenes sessile cells of about 2.5 and 2.8 Log CFU/cm[2] after 72 h, respectively. However, L. monocytogenes gained the protection of P. fluorescens, evading CEO treatment and showing a minimal sessile cell reduction of 0.7 Log CFU/cm[2] after 72 h. Considering the outcome of this study, CEO might have promising perspectives for applications in dairy facilities.}, } @article {pmid37060635, year = {2023}, author = {Akbarzadeh, I and Rezaei, N and Bazzazan, S and Mezajin, MN and Mansouri, A and Karbalaeiheidar, H and Ashkezari, S and Moghaddam, ZS and Lalami, ZA and Mostafavi, E}, title = {In silico and in vitro studies of GENT-EDTA encapsulated niosomes: A novel approach to enhance the antibacterial activity and biofilm inhibition in drug-resistant Klebsiella pneumoniae.}, journal = {Biomaterials advances}, volume = {149}, number = {}, pages = {213384}, doi = {10.1016/j.bioadv.2023.213384}, pmid = {37060635}, issn = {2772-9508}, mesh = {Anti-Bacterial Agents/pharmacology/chemistry ; Edetic Acid/chemistry/pharmacology ; *Klebsiella pneumoniae/genetics ; *Liposomes ; Molecular Docking Simulation ; }, abstract = {Klebsiella pneumoniae (Kp) is a common pathogen inducing catheter-related biofilm infections. Developing effective therapy to overcome antimicrobial resistance (AMR) in Kp is a severe therapeutic challenge that must be solved. This study aimed to prepare niosome-encapsulated GENT (Gentamicin) and EDTA (Ethylenediaminetetraacetic acid) (GENT-EDTA/Nio) to evaluate its efficacy toward Kp strains. The thin-film hydration method was used to prepare various formulations of GENT-EDTA/Nio. Formulations were characterized for their physicochemical characteristics. GENT-EDTA/Nio properties were used for optimization with Design-Expert Software. Molecular docking was utilized to determine the antibacterial activity of GENT. The niosomes displayed a controlled drug release and storage stability of at least 60 days at 4 and 25 °C. GENT-EDTA/Nio performance as antimicrobial agents has been evaluated by employing agar well diffusion method, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) against the Kp bacteria strains. Biofilm formation was investigated after GENT-EDTA/Nio administration through different detection methods, which showed that this formulation reduces biofilm formation. The effect of GENT-EDTA/Nio on the expression of biofilm-related genes (mrkA, ompA, and vzm) was estimated using QRT-PCR. MTT assay was used to evaluate the toxicity effect of niosomal formulations on HFF cells. The present study results indicate that GENT-EDTA/Nio decreases Kp's resistance to antibiotics and increases its antibiotic and anti-biofilm activity and could be helpful as a new approach for drug delivery.}, } @article {pmid37059195, year = {2023}, author = {Gholipour, S and Shamsizadeh, Z and Gwenzi, W and Nikaeen, M}, title = {The bacterial biofilm resistome in drinking water distribution systems: A systematic review.}, journal = {Chemosphere}, volume = {329}, number = {}, pages = {138642}, doi = {10.1016/j.chemosphere.2023.138642}, pmid = {37059195}, issn = {1879-1298}, mesh = {Humans ; *Drinking Water ; Renal Dialysis ; Bacteria ; Biofilms ; Genes, Bacterial ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Antibiotic resistance in drinking water systems poses human health risks. Earlier studies, including reviews on antibiotic resistance in drinking water systems are limited to the occurrence, behaviour and fate in bulk raw water and drinking water treatment systems. By comparison, reviews on the bacterial biofilm resistome in drinking water distribution systems are still limited. Therefore, the present systematic review investigates the occurrence, behaviour and fate and, detection methods of bacterial biofilm resistome in the drinking water distribution systems. A total of 12 original articles drawn from 10 countries were retrieved and analyzed. Antibiotic resistant bacteria and antibiotic resistance genes detected in biofilms include those for sulfonamides, tetracycline, and beta-lactamase. The genera detected in biofilms include Staphylococcus, Enterococcus, Pseudomonas, Ralstonia, Mycobacteria, as well as Enterobacteriaceae family and other gram-negative bacteria. The presence of Enterococcus faecium, Staphylococcusaureus, Klebsiella pneumoniae, Acinetobacterbaumannii, Pseudomonas aeruginosa, and Enterobacter species (ESKAPE bacteria) among the detected bacteria points to potential human exposure and health risks especially for susceptible individuals via the consumption of drinking water. Besides, the effects of water quality parameter and residual chlorine, the physico-chemical factors controlling the emergence, persistence and fate of the biofilm resistome are still poorly understood. Culture-based methods, and molecular methods, and their advantages and limitations are discussed. The limited data on the bacterial biofilm resistome in drinking water distribution system points to the need for further research. To this end, future research directions are discussed including understanding the formation, behaviour, and fate of the resistome and the controlling factors.}, } @article {pmid37058918, year = {2023}, author = {Zhao, Q and Li, J and Deng, L and Jia, T and Zhao, Y and Li, X and Peng, Y}, title = {From hybrid process to pure biofilm anammox process: Suspended sludge biomass management contributing to high-level anammox enrichment in biofilms.}, journal = {Water research}, volume = {236}, number = {}, pages = {119959}, doi = {10.1016/j.watres.2023.119959}, pmid = {37058918}, issn = {1879-2448}, mesh = {*Sewage/microbiology ; Wastewater ; Biomass ; Anaerobic Ammonia Oxidation ; Denitrification ; Bioreactors/microbiology ; Oxidation-Reduction ; Anaerobiosis ; Bacteria/genetics ; Biofilms ; Nitrogen ; *Ammonium Compounds ; }, abstract = {The application of mainstream anammox is highly desirable for municipal wastewater treatment. However, enrichment of anammox bacteria (AnAOB) is challenging, particularly given the vicious competition from denitrifying bacteria (DB). Here, suspended sludge biomass management, a novel operational strategy for hybrid process (suspended sludge/biofilm), was investigated for 570 days based on a modified anaerobic-anoxic-oxic system treating municipal wastewater. By successively decreasing the suspended sludge concentration, the traditional hybrid process was successfully upgraded to a pure biofilm anammox process. During this process, both the nitrogen removal efficiency (NRE) and rate (NRR) were significantly improved (P < 0.001), from 62.1 ± 4.5% to 79.2 ± 3.9% and from 48.7 ± 9.7 to 62.3 ± 9.0 g N/(m[3]·d), respectively. Mainstream anammox was improved in the following: Candidatus Brocadia was enriched from 0.70% to 5.99% in anoxic biofilms [from (9.94 ± 0.99) × 10[8] to (1.16 ± 0.01) × 10[10] copies/g VSS, P < 0.001]; the in situ anammox reaction rate increased from 8.8 ± 1.9 to 45.5 ± 3.2 g N/(m[3]·d) (P < 0.001); the anammox contribution to nitrogen removal rose from 9.2 ± 2.8% to 67.1 ± 8.3% (P < 0.001). Core bacterial microbiome analysis, functional gene quantification, and a series of ex situ batch experiments demonstrated that the stepwise decreases in suspended sludge concentration effectively mitigated the vicious competition of DB against AnAOB, enabling high-level AnAOB enrichment. This study presents a straightforward and effective strategy for enriching AnAOB in municipal wastewater, shedding fresh light on the application and upgradation of mainstream anammox.}, } @article {pmid37058467, year = {2023}, author = {Böhning, J and Dobbelstein, AW and Sulkowski, N and Eilers, K and von Kügelgen, A and Tarafder, AK and Peak-Chew, SY and Skehel, M and Alva, V and Filloux, A and Bharat, TAM}, title = {Architecture of the biofilm-associated archaic Chaperone-Usher pilus CupE from Pseudomonas aeruginosa.}, journal = {PLoS pathogens}, volume = {19}, number = {4}, pages = {e1011177}, pmid = {37058467}, issn = {1553-7374}, support = {202231/Z/16/Z/WT_/Wellcome Trust/United Kingdom ; MR/K501256/1/MRC_/Medical Research Council/United Kingdom ; MR/N013468/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Humans ; *Pseudomonas aeruginosa/metabolism ; *Fimbriae, Bacterial/metabolism ; Biofilms ; Adhesins, Bacterial/metabolism ; Molecular Chaperones/metabolism ; Fimbriae Proteins/metabolism ; }, abstract = {Chaperone-Usher Pathway (CUP) pili are major adhesins in Gram-negative bacteria, mediating bacterial adherence to biotic and abiotic surfaces. While classical CUP pili have been extensively characterized, little is known about so-called archaic CUP pili, which are phylogenetically widespread and promote biofilm formation by several human pathogens. In this study, we present the electron cryomicroscopy structure of the archaic CupE pilus from the opportunistic human pathogen Pseudomonas aeruginosa. We show that CupE1 subunits within the pilus are arranged in a zigzag architecture, containing an N-terminal donor β-strand extending from each subunit into the next, where it is anchored by hydrophobic interactions, with comparatively weaker interactions at the rest of the inter-subunit interface. Imaging CupE pili on the surface of P. aeruginosa cells using electron cryotomography shows that CupE pili adopt variable curvatures in response to their environment, which might facilitate their role in promoting cellular attachment. Finally, bioinformatic analysis shows the widespread abundance of cupE genes in isolates of P. aeruginosa and the co-occurrence of cupE with other cup clusters, suggesting interdependence of cup pili in regulating bacterial adherence within biofilms. Taken together, our study provides insights into the architecture of archaic CUP pili, providing a structural basis for understanding their role in promoting cellular adhesion and biofilm formation in P. aeruginosa.}, } @article {pmid37057638, year = {2023}, author = {Singha, S and Thomas, R and Kumar, A and Bharadwaj, D and Vishwakarma, JN and Gupta, VK}, title = {Presence of potent inhibitors of bacterial biofilm associated proteins is the key to Citrus limon's antibiofilm activity against pathogenic Escherichia coli.}, journal = {Biofouling}, volume = {39}, number = {2}, pages = {171-188}, doi = {10.1080/08927014.2023.2199934}, pmid = {37057638}, issn = {1029-2454}, mesh = {*Escherichia coli ; Biofilms ; Bacterial Proteins ; *Citrus ; Anti-Bacterial Agents/pharmacology ; Phytochemicals ; Plant Extracts/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {In an era of antibiotic resistance where natural antibiotic substitutes are considered essential, the antimicrobial and antibiofilm activities of Citrus limon extract on strains of pathogenic Escherichia coli isolated from pork were evaluated. The strains which form biofilms were more resistant (MIC50 = 2.5 mgml[-1]) compared to non-biofilm forming strains (MIC50 = 1.25 mgml[-1]). Use of C. limon extract at 20 mgml[-1] concentration has resulted in inhibition of biofilm formation by 53.96%. Cyclobarbital, 5, 8-dimethoxycumarin, orotic acid and 3-methylsalicylhydrazide were the major phytochemicals in C. limon extract with highest docking affinities against the biofilm associated proteins in E. coli. The results of simulation studies have clearly illustrated the energy stability of the protein-ligand complexes. Absorption, distribution, metabolism, excretion and toxicity (ADMET) profiles revealed that the phytochemicals in C. limon could be used in the drug design studies to preferentially target the specific receptors to combat biofilms associated with E. coli.}, } @article {pmid37057584, year = {2022}, author = {Narasimman, M and Ory, J and Bartra, SS and Plano, GV and Ramasamy, R}, title = {Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis.}, journal = {The journal of sexual medicine}, volume = {19}, number = {6}, pages = {1024-1031}, doi = {10.1016/j.jsxm.2022.03.602}, pmid = {37057584}, issn = {1743-6109}, mesh = {Humans ; *Penile Prosthesis/microbiology ; Rifampin/therapeutic use ; Staphylococcus aureus ; Gentian Violet ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Gentamicins/pharmacology ; Bacteria ; Postoperative Complications/drug therapy ; }, abstract = {BACKGROUND: Delayed infection, thought to be due to gradual biofilm formation, remains a feared complication after inflatable penile prosthesis (IPP) insertion. Understanding and preventing biofilm formation is necessary to prevent infections.

AIM: To develop an in vitro model and compare growth of biofilm by different bacteria on IPPs and evaluate the anti-infective efficacy of the Coloplast Titan and AMS 700 InhibiZone.

METHODS: Sterile IPPs (Coloplast) were cut into rings and incubated with S. epidermidis, S. aureus, P. aeruginosa, A. baumannii, or K. pneumoniae cultures in tryptic soy broth (TSB) (4 hour) to ensure adequate bacteria attachment, and then in only TSB (120 hours) to allow for biofilm formation. Rings were fixed with ethanol and biofilm measured by spectrophotometer (OD570) after crystal violet staining. This methodology was repeated for S. epidermidis and P. aeruginosa with Coloplast rings dipped in 10 ml of a 10 mg/ml Rifampin, 1 mg/ml Gentamicin, and deionized water solution and undipped AMS InhibiZone rings. Crystal violet assay (OD570) was repeated after incubation within bacteria (2 hour), and then only TSB (120 hours).

OUTCOMES: The primary outcome of the study was OD570 readings, indirectly measuring biofilm mass on implant rings.

RESULTS: S. epidermidis, S. aureus, A. baumannii, P. aeruginosa, and K. pneumoniae all formed significant biofilm. P. aeruginosa showed the strongest predilection to grow biofilm on IPPs. P. aeruginosa also formed significant biofilm on antibiotic-treated Coloplast and AMS rings, while S. epidermidis was inhibited. No significant difference was found in biofilm inhibition between the implants.

CLINICAL TRANSLATION: Our findings suggest gram-negative bacteria may form biofilm more proficiently and quickly on IPPs than gram-positive organisms. Commonly used antibiotic treatments on IPPs may be effective against S. epidermidis but not against P. aeruginosa biofilm formation.

STRENGTHS & LIMITATIONS: This is the first study comparing biofilm formation by different bacteria organisms on IPPs and the inhibitive ability of Coloplast and AMS implants against biofilm formation. Clinical data on organisms responsible for infected IPPs is needed to determine the clinical relevance of our findings.

CONCLUSION: Our novel in vitro model of biofilm formation of IPPs evaluated the effect of a gentamicin/rifampin antibiotic dip on Coloplast Titan implants and the anti-infective capacity of the minocycline/rifampin precoated AMS 700 InhibiZone against S. epidermidis and P. aeruginosa. P. aeruginosa was able to grow on both antibiotic-treated implants, with no significant difference, and should continue to be a specific target of investigation to reduce delayed post-operative IPP infections.}, } @article {pmid37057221, year = {2023}, author = {Saidi, N and Saderi, H and Owlia, P and Soleimani, M}, title = {Anti-Biofilm Potential of Lactobacillus casei and Lactobacillus rhamnosus Cell-Free Supernatant Extracts against Staphylococcus aureus.}, journal = {Advanced biomedical research}, volume = {12}, number = {}, pages = {50}, pmid = {37057221}, issn = {2277-9175}, abstract = {BACKGROUND: Biofilm production is an important virulence factor in Staphylococcus aureus. Most of the infections associated with biofilms of this bacterium are very difficult to treat using antibiotics. The present research studied the effects of the two probiotic Lactobacillus species L. casei and L. rhamnosus on S. aureus biofilm.

MATERIALS AND METHODS: Cell-free supernatant (CFS) extracts of L. casei ATCC 39392 and L. rhamnosus ATCC 7469 culture were prepared. The effects of sub-minimum inhibitory concentrations of the CFS extracts on cell surface hydrophobicity (CSH), initial attachment, biofilm formation, and their ability in eradicating S. aureus ATCC 33591 biofilms were assessed. In addition, the effects of CFS extracts on expression of the genes involved in formation of S. aureus biofilms (cidA, hld, sarA, icaA, and icaR) were also evaluated through real-time polymerase chain reaction.

RESULTS: CFSs of both Lactobacillus spp. significantly reduced CSH, initial attachment, and biofilm formation and eradicated the biofilms. The above findings were supported by scanning electron microscopy results. These two Lactobacillus CFSs significantly changed the expression of all studied biofilm-related genes. Expression levels of cidA, hld, and icaR genes significantly increased by 4.4, 2.3, and 4.76 fold, respectively, but sarA and icaA genes were significantly downregulated by 3.12 and 2.3 fold.

CONCLUSION: The results indicated that CFS extracts of L. casei and L. rhamnosus had desirable antagonistic and anti-biofilm effects against S. aureus. Consequently, carrying out further research enables us to prepare pharmaceuticals from these CFSs in order to prevent and treat infections caused by S. aureus biofilms.}, } @article {pmid37056424, year = {2023}, author = {Xu, Q and Chen, S and Jiang, L and Xia, C and Zeng, L and Cai, X and Jin, Z and Qin, S and Ding, W and He, Q}, title = {Sonocatalytic hydrogen/hole-combined therapy for anti-biofilm and infected diabetic wound healing.}, journal = {National science review}, volume = {10}, number = {5}, pages = {nwad063}, pmid = {37056424}, issn = {2053-714X}, abstract = {It is a great challenge to effectively eradicate biofilm and cure biofilm-infected diseases because dense extracellular polymeric substance matrix prevents routine antibacterial agents from penetrating into biofilm. H2 is an emerging energy-regulating molecule possessing both high biosafety and high tissue permeability. In this work, we propose a concept of sonocatalytic hydrogen/hole-combined 'inside/outside-cooperation' anti-biofilm for promoting bacteria-infected diabetic wound healing based on two-dimensional piezoelectric nanomaterials. Proof-of-concept experiments using C3N4 nanosheets as a representative piezoelectric catalyst with wide band gap and high biosafety have verified that sonocatalytically generated H2 and holes rapidly penetrate into biofilm to inhibit bacterial energy metabolism and oxidatively deprive polysaccharides/NADH in biofilm to destroy the bacterial membrane/electron transport chain, respectively, inside/outside-cooperatively eradicating biofilm. A bacteria-infected diabetic wound model is used to confirm the excellent in vivo antibacterial performance of sonocatalytic hydrogen/hole-combined therapy, remarkably improving bacteria-infected diabetic wound healing. The proposed strategy of sonocatalytic hole/hydrogen-combined 'inside/outside-cooperation' will make a highway for treatment of deep-seated biofilm infection.}, } @article {pmid37055625, year = {2023}, author = {Bezerra, FM and Rocchetti, TT and Lima, SL and Yu, MCZ and da Matta, DA and Höfling-Lima, AL and Melo, ASA and de Oliveira, LA}, title = {Candida species causing fungal keratitis: molecular identification, antifungal susceptibility, biofilm formation, and clinical aspects.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {2}, pages = {629-636}, pmid = {37055625}, issn = {1678-4405}, mesh = {Humans ; *Antifungal Agents/pharmacology/therapeutic use ; Candida ; Amphotericin B/pharmacology ; Candida parapsilosis/genetics ; *Keratitis/drug therapy ; Candida albicans ; Microbial Sensitivity Tests ; Biofilms ; Drug Resistance, Fungal ; }, abstract = {The study aimed to evaluate the clinical aspects, molecular identification, biofilm formation, and antifungal susceptibility profile of Candida species isolated from fungal keratitis. Thirteen Candida isolates from 13 patients diagnosed with Candida keratitis were retrieved and grown in pure culture. Species identification was performed by micromorphology analysis and ITS-rDNA sequencing. The broth microdilution method tested the minimum inhibitory concentration (MIC) of four antifungal drugs (fluconazole, amphotericin B, voriconazole, and anidulafungin). The biofilms were cultured and incubated with antifungal drugs for 24 h. The XTT reduction assay measured the biofilm activity. Biofilm MICs were calculated based on a 50% reduction in metabolic activity compared with the activity of the drug-free control. Among isolates, two were C. albicans, 10 were C. parapsilosis (sensu stricto), and one was C. orthopsilosis. All isolates were classified as susceptible or intermediate to all four antifungal drugs. Four isolates were very low biofilm producers (30%). Nine isolates were biofilm producers, and all biofilm samples were unsusceptible to all drugs tested. Previous ocular surgery was the most common underlying condition for fungal keratitis (84.6%), and C. parapsilosis was the most frequent Candida species (76.9%). Four patients (30.7%) needed keratoplasty, whereas two (15.3%) required evisceration. The biofilm formation ability of Candida isolates decreased antifungal susceptibility compared with planktonic cells. Despite in vitro antifungal susceptibility, almost half of the patients were unresponsive to clinical treatment and needed surgery.}, } @article {pmid37055614, year = {2023}, author = {Wang, T and Shen, P and He, Y and Zhang, Y and Liu, J}, title = {Spatial transcriptome uncovers rich coordination of metabolism in E. coli K12 biofilm.}, journal = {Nature chemical biology}, volume = {}, number = {}, pages = {}, pmid = {37055614}, issn = {1552-4469}, support = {20197030008//Tsinghua University (THU)/ ; 32170099//National Natural Science Foundation of China (National Science Foundation of China)/ ; 32100071//National Natural Science Foundation of China (National Science Foundation of China)/ ; 21908129//National Natural Science Foundation of China (National Science Foundation of China)/ ; }, abstract = {Microbial communities often display region-specific properties, which give rise to complex interactions and emergent behaviors that are critical to the homeostasis and stress response of the communities. However, systems-level understanding of these properties still remains elusive. In this study, we established RAINBOW-seq and profiled the transcriptome of Escherichia coli biofilm communities with high spatial resolution and high gene coverage. We uncovered three modes of community-level coordination, including cross-regional resource allocation, local cycling and feedback signaling, which were mediated by strengthened transmembrane transport and spatially specific activation of metabolism. As a consequence of such coordination, the nutrient-limited region of the community maintained an unexpectedly high level of metabolism, enabling it to express many signaling genes and functionally unknown genes with potential sociality functions. Our work provides an extended understanding of the metabolic interplay in biofilms and presents a new approach of investigating complex interactions in bacterial communities on the systems level.}, } @article {pmid37051725, year = {2023}, author = {Sanders, MK and Duarte, S and Ayoub, HM and Scully, AC and Vinson, LA and Gregory, RL}, title = {Effect of titanium dioxide on Streptococcus mutans biofilm.}, journal = {Journal of applied biomaterials & functional materials}, volume = {21}, number = {}, pages = {22808000221131892}, doi = {10.1177/22808000221131892}, pmid = {37051725}, issn = {2280-8000}, mesh = {Humans ; Streptococcus mutans ; Reactive Oxygen Species/metabolism ; *Metal Nanoparticles ; Silver/pharmacology ; *Dental Caries ; Biofilms ; }, abstract = {BACKGROUND: Streptococcus mutans (S. mutans) participates in the dental caries process. Titanium dioxide (TiO2) nanoparticles produce reactive oxygen species capable of disrupting bacterial DNA synthesis by creating pores in cell walls and membranes.

OBJECTIVE: The objective of this study was to determine the effect of TiO2 on the disruption of S. mutans biofilm.

METHODS: This study was conducted in four phases involving a TiO2-containing toothbrush and TiO2 nanoparticles. Each phase was completed using 24 h established S. mutans biofilm growth. Phase one data was collected through a bacterial plating study, assessing biofilm viability. Biofilm mass was evaluated in phase two of the study by measuring S. mutans biofilm grown on microtiter plates following crystal violet staining. The third phase of the study involved a generalized oxygen radical assay to determine the relative amount of oxygen radicals released intracellularly. Phase four of the study included the measurement of insoluble glucan/extracellular polysaccharide (EPS) synthesis using a phenol-sulfuric acid assay.

RESULTS: Both exposure time and time intervals had a significant effect on bacterial viability counts (p = 0.0323 and p = 0.0014, respectively). Bacterial counts after 6 min of exposure were significantly lower than after 2 min (p = 0.034), compared to the no treatment control (p = 0.0056). As exposure time increased, the amount of remaining biofilm mass was statistically lower than the no treatment control. Exposure time had a significant effect on oxygen radical production. Both the 30 and 100 nm TiO2 nanoparticles had a significant effect on bacterial mass. The silver nanoparticles and the 30 and 100 nm TiO2 nanoparticles significantly inhibited EPS production.

CONCLUSION: The TiO2-containing toothbrush kills, disrupts, and produces oxygen radicals that disrupt established S. mutans biofilm. TiO2 and silver nanoparticles inhibit EPS production and reduce biofilm mass. The addition of TiO2 to dental products may be effective in reducing cariogenic dental biofilm.}, } @article {pmid37051555, year = {2022}, author = {Larijani, M and Zareshahrabadi, Z and Alhavaz, A and Hajipour, R and Ranjbaran, A and Giti, R and Soltankarimi, V and Zomorodian, K}, title = {Evaluation of Candida albicans biofilm formation on conventional and computer-aided-design/computer-aided manufacturing (CAD/CAM) denture base materials.}, journal = {Current medical mycology}, volume = {8}, number = {3}, pages = {23-29}, pmid = {37051555}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: The human mouth mucosal surface is colonized by indigenous microflora, which normally maintains an ecological balance among different species. However, certain environmental or biological factors may disrupt this balance, leading to microbial diseases. Candida albicans biofilms are formed on indwelling medical devices and have an association with both oral and invasive candidiasis. This study aimed to compare the amount of adherent C. albicans and the biofilm formed on different denture base materials. The adhesion of C. albicans to denture base materials is widely recognized as the main reason for the development of denture stomatitis.

MATERIALS AND METHODS: In total, 56 polymethyl methacrylate (PMMA) acrylic resin disc-shaped samples were divided into four groups as follows: 1) chemically polymerized PMMA, 2) heat-polymerized PMMA, 3) computer-aided design and computer-aided manufacturing (CAD/CAM) PMMA in high polish, and 4) CAD/CAM resins in glazed form. The adherent cells and formation of C. albicans strains (562, 1905, 1912, and 1949) biofilm were measured by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) method and use of a microplate reader. Moreover, morphological alterations of C. albicans cells were investigated using scanning electron microscopy (SEM).

RESULTS: The biofilm formation was significantly lower on CAD/CAM acrylic resins, compared to conventional denture base materials. The obtained results were confirmed by the SEM images of C. albicans biofilms. CAD/CAM PMMA-based polymers may be preferable to inhibit C. albicans biofilm formation and reduce Candida-associated denture stomatitis in long-term use.

CONCLUSION: Based on the findings, the CAD/CAM technique can be used as an efficient technique for denture fabrication as it inhibits microbial accumulation, and consequently, microbial biofilm.}, } @article {pmid37050896, year = {2023}, author = {Wang, Y and Zhang, L and Yuan, X and Wang, D}, title = {Treatment with paeoniflorin increases lifespan of Pseudomonas aeruginosa infected Caenorhabditis elegans by inhibiting bacterial accumulation in intestinal lumen and biofilm formation.}, journal = {Frontiers in pharmacology}, volume = {14}, number = {}, pages = {1114219}, pmid = {37050896}, issn = {1663-9812}, abstract = {Paeoniflorin is one of the important components in Paeoniaceae plants. In this study, we used Caenorhabditis elegans as a model host and Pseudomonas aeruginosa as a bacterial pathogen to investigate the possible role of paeoniflorin treatment against P. aeruginosa infection in the host and the underlying mechanisms. Posttreatment with 1.25-10 mg/L paeoniflorin could significantly increase the lifespan of P. aeruginosa infected nematodes. After the infection, the P. aeruginosa colony-forming unit (CFU) and P. aeruginosa accumulation in intestinal lumen were also obviously reduced by 1.25-10 mg/L paeoniflorin treatment. The beneficial effects of paeoniflorin treatment in increasing lifespan in P. aeruginosa infected nematodes and in reducing P. aeruginosa accumulation in intestinal lumen could be inhibited by RNAi of pmk-1, egl-1, and bar-1. In addition, paeoniflorin treatment suppressed the inhibition in expressions of pmk-1, egl-1, and bar-1 caused by P. aeruginosa infection in nematodes, suggesting that paeoniflorin could increase lifespan of P. aeruginosa infected nematode by activating PMK-1, EGL-1, and BAR-1. Moreover, although treatment with 1.25-10 mg/L paeoniflorin did not show obvious anti-P. aeruginosa activity, the P. aeruginosa biofilm formation and expressions of related virulence genes (pelA, pelB, phzA, lasB, lasR, rhlA, and rhlC) were significantly inhibited by paeoniflorin treatment. Treatment with 1.25-10 mg/L paeoniflorin could further decrease the levels of related virulence factors of pyocyanin, elastase, and rhamnolipid. In addition, 2.5-10 mg/L paeoniflorin treatment could inhibit the swimming, swarming, and twitching motility of P. aeruginosa, and treatment with 2.5-10 mg/L paeoniflorin reduced the cyclic-di-GMP (c-di-GMP) level. Therefore, paeoniflorin treatment has the potential to extend lifespan of P. aeruginosa infected hosts by reducing bacterial accumulation in intestinal lumen and inhibiting bacterial biofilm formation.}, } @article {pmid37050135, year = {2023}, author = {Fontana, R and Caproni, A and Sicurella, M and Manfredini, S and Baldisserotto, A and Marconi, P}, title = {Effects of Flavonoids and Phenols from Moringa oleifera Leaf Extracts on Biofilm Processes in Xanthomonas campestris pv. campestris.}, journal = {Plants (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, pmid = {37050135}, issn = {2223-7747}, abstract = {Xanthomonas campestris pv. campestris is the causal agent of black rot in crucifers, a plant disease with significant economic impact. Xanthomonadaceae is a large family of Gram-negative bacteria that cause symptoms by blocking water flow in plants by invading the xylem. To accomplish this, the main mechanism the bacteria use to adapt to environmental changes and colonize tissues is biofilm formation. In recent years, growing interest in natural antimicrobial compounds has led to the study of different phytocomplexes derived from plants. In this work, Moringa oleifera was selected, as its leaves are rich in phenols, essential oils, and vitamins that exert antibacterial activity. X. campestris pv. campestris biofilm, one of its major virulence factors, was studied. Biofilm formation and removal were analyzed on abiotic and biotic surfaces with and without M. oleifera leaf extracts. The data from the analysis show that Moringa oleifera leaf extracts and single phenols were able to inhibit biofilm growth on abiotic surfaces, but the activity of the whole phytocomplex was significantly higher compared to that of individual phenols. The effect of Moringa oleifera extracts on cabbage leaves in vivo was also found to be very important, as scanning electron microscopy showed that treatment with the extracts led to clear unblocking of the xylem, implying many advantages for use in black rot control.}, } @article {pmid37049901, year = {2023}, author = {Yu, M and Xin, J and Liu, Y and Chen, Y and Zhao, H and Li, Y and Hou, Y and Jia, M and Wang, B and Li, M}, title = {Pharmacological Characters and Toxicity Evaluation of Coumarin Derivative LP4C as Lead Compound against Biofilm Formation of Pseudomonas aeruginosa.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {7}, pages = {}, pmid = {37049901}, issn = {1420-3049}, mesh = {Animals ; Mice ; Anti-Bacterial Agents/pharmacology/metabolism ; Pseudomonas aeruginosa ; Biofilms ; *Anti-Infective Agents/pharmacology ; *Pseudomonas Infections/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Pseudomonas aeruginosa-induced biofilm infection is difficult to treat and poses a significant threat to public health. Our previous study found a new coumarin derivative LP4C which exerted potent in vitro and in vivo anti-biofilm activity against Pseudomonas aeruginosa; however, the underlying molecular mechanism and drug-likeness of LP4C is unclear. In this study, we confirmed that LP4C could inhibit the biofilm in dose-dependent manner without bactericidal activity. The transcriptomic profiling and RT-PCR result revealed that bacterial pyrimidine mediated the inhibitory activity of LP4C. The cell viability was not affected in LP4C treatment groups with the concentration under 200 μg/mL, and no death or toxicity sign was observed in mice treated by 20, 40 and 80 mg/kg LP4C during the three-week test period. Ames test presented that LP4C had no effect on the bacterial reverse mutation. In additional, pharmacokinetic results showed that LP4C was likely to have the orally bioavailable properties. Our data indicate that LP4C is a possible lead compound for the development of new anti-biofilm infection agents against Pseudomonas aeruginosa.}, } @article {pmid37049615, year = {2023}, author = {Rizzo, G and Pineda Chavez, SE and Vandenkoornhuyse, E and Cárdenas Rincón, CL and Cento, V and Garlatti, V and Wozny, M and Sammarco, G and Di Claudio, A and Meanti, L and Elangovan, S and Romano, A and Roda, G and Loy, L and Dal Buono, A and Gabbiadini, R and Lovisa, S and Rusconi, R and Repici, A and Armuzzi, A and Vetrano, S}, title = {Pomegranate Extract Affects Gut Biofilm Forming Bacteria and Promotes Intestinal Mucosal Healing Regulating the Crosstalk between Epithelial Cells and Intestinal Fibroblasts.}, journal = {Nutrients}, volume = {15}, number = {7}, pages = {}, pmid = {37049615}, issn = {2072-6643}, mesh = {Humans ; Mice ; Animals ; Caco-2 Cells ; Dextrans/therapeutic use ; *Pomegranate ; In Situ Hybridization, Fluorescence ; Mice, Inbred C57BL ; Epithelial Cells/metabolism ; *Colitis/chemically induced/drug therapy/genetics ; *Inflammatory Bowel Diseases/metabolism ; Wound Healing ; Intestinal Mucosa/metabolism ; Bacteria/genetics ; Dextran Sulfate/pharmacology ; Disease Models, Animal ; }, abstract = {Background: Pomegranate (Punica granatum) can be used to prepare a bioactive extract exerting anti-inflammatory activities. Clinical studies demonstrated an improvement in clinical response in inflammatory bowel disease (IBD) patients when pomegranate extract (PG) was taken as a complement to standard medications. However, the molecular mechanisms underlying its beneficial effects are still scarcely investigated. This study investigates the effect of PG on bacterial biofilm formation and the promotion of mucosal wound healing. Methods: The acute colitis model was induced in C57BL/6N mice by 3% dextran sodium sulfate administration in drinking water for 5 days. During the recovery phase of colitis, mice received saline or PG (200 mg/kg body weight) by oral gavage for 11 days. Colitis was scored daily by evaluating body weight loss, bleeding, and stool consistency. In vivo intestinal permeability was evaluated by fluorescein isothiocyanate-conjugated dextran assay, bacterial translocation was assessed by fluorescence in situ hybridization on tissues, whereas epithelial and mucus integrity were monitored by immunostaining for JAM-A and MUC-2 markers. Bacterial biofilm formation was assessed using microfluidic devices for 24 or 48 h. Primary fibroblasts were isolated from healthy and inflamed areas of 8 IBD patients, and Caco-2 cells were stimulated with or without PG (5 μg/mL). Inflammatory mediators were measured at the mRNA and protein level by RT-PCR, WB, or Bio-plex multiplex immunoassay, respectively. Results: In vivo, PG boosted the recovery phase of colitis, promoting a complete restoration of the intestinal barrier with the regeneration of the mucus layer, as also demonstrated by the absence of bacterial spread into the mucosa and the enrichment of crypt-associated fibroblasts. Microfluidic experiments did not highlight a specific effect of PG on Enterobacterales biofilm formation, even though Citrobacter freundii biofilm was slightly impaired in the presence of PG. In vitro, inflamed fibroblasts responded to PG by downregulating the release of metalloproteinases, IL-6, and IL-8 and upregulating the levels of HGF. Caco-2 cells cultured in a medium supplemented with PG increased the expression of SOX-9 and CD44, whereas in the presence of HGF or plated with a fibroblast-conditioned medium, they displayed a decrease in SOX-9 and CD44 expression and an increase in AXIN2, a negative regulator of Wnt signaling. Conclusions: These data provide new insight into the manifold effects of PG on promoting mucosal homeostasis in IBD by affecting pathogen biofilm formation and favoring the regeneration of the intestinal barrier through the regulation of the crosstalk between epithelial and stromal cells.}, } @article {pmid37048337, year = {2023}, author = {Li, J and Mu, G and Tuo, Y}, title = {Phenotypic Traits and Probiotic Functions of Lactiplantibacillus plantarum Y42 in Planktonic and Biofilm Forms.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, pmid = {37048337}, issn = {2304-8158}, abstract = {Bacteria in planktonic and biofilm forms exhibit different phenotypic properties. In this study, the phenotypic traits and probiotic functions of Lactiplantibacillus plantarum Y42 in planktonic and biofilm forms were assessed. After 36 h of static culture, scanning electron microscopy and confocal laser scanning microscopy showed that the L. plantarum Y42 bacterial cells contained interconnected adhesive matter on the surface, forming a ~18 μm layer of dense biofilms. The surface properties of L. plantarum Y42 in biofilm form, including autoaggregation ability, hydrophobicity, acid-base charge, and adhesiveness, were all higher than those in the planktonic form. Biofilm L. plantarum Y42 showed a higher tolerance to adverse environmental conditions and a higher survival rate, enzymatic activity, and integrity after vacuum lyophilization. And biofilm L. plantarum Y42 had higher adhesion to human enterocyte HT-29 cell monolayers, inhibited the expressions of proinflammatory factors IL-6 and TNF-α, and promoted the expressions of the anti-inflammatory factor IL-10 and barrier proteins Claudin-1 and Occludin. In addition, L. plantarum Y42 in biofilm form can inhibit the adhesion and invasion of Listeria monocytogenes ATCC 19115 to HT-29 cell monolayers and is more effective in relieving the inflammatory reactions and injuries of HT-29 cells caused by L. monocytogenes ATCC 19115. In conclusion, L. plantarum Y42 in biofilm form exhibited better probiotic functions compared to that in planktonic form. This indicated that L. plantarum Y42 can form biofilms to enhance its probiotic functions, which provided a theoretical basis for better development and utilization of L. plantarum Y42.}, } @article {pmid37048183, year = {2023}, author = {He, J and Gao, X and Huang, H and Hao, J}, title = {Proposal and Verification of the Theory of Layer-by-Layer Elimination of Biofilm in Listeria monocytogenes.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {7}, pages = {}, pmid = {37048183}, issn = {2304-8158}, support = {No. 31972170//National Natural Science Foundation of China/ ; No. C2022208010//Hebei Natural Science Foundation of China/ ; }, abstract = {Biofilms are microbial communities that represent a high abundance of microbial life forms on Earth. Within biofilms, structural changes during clearance processes occur in three spatial and temporal dimensions; therefore, microscopy and quantitative image analysis are essential in elucidating their function. Here, we present confocal laser scanning microscopy (CLSM) in conjunction with ISA-2 software analysis for the automated and high-throughput quantification, analysis, and visualisation of biofilm interiors and overall biofilm properties in three spatial and temporal dimensions. This paper discusses the removal process of Listeria monocytogenes (LM) biofilms using slightly acidic electrolytic water, non-electrolytic hypochlorite water, and alternating the use of strongly acidic and strongly alkaline electrolytic water. The results show that the biofilm gradually thins and gutters from the initial viscous dense and thick morphology under the action of either biocide. This process is consistent with first-level kinetics. After CLSM filming to observe the biofilm structure, analysis software was used to process and quantify the biovolume, average biofilm thickness, biofilm roughness and other indicators; fluorescence enzyme markers were used to verify the remaining amount of extracellular nucleic acid. In this study, we proposed and validated the theory of layer-by-layer elimination of LM biofilm.}, } @article {pmid37047667, year = {2023}, author = {Pezzotti, G and Ofuji, S and Imamura, H and Adachi, T and Yamamoto, T and Kanamura, N and Ohgitani, E and Marin, E and Zhu, W and Mazda, O and Togo, A and Kimura, S and Iwata, T and Shiba, H and Ouhara, K and Aoki, T and Kawai, T}, title = {In Situ Raman Analysis of Biofilm Exopolysaccharides Formed in Streptococcus mutans and Streptococcus sanguinis Commensal Cultures.}, journal = {International journal of molecular sciences}, volume = {24}, number = {7}, pages = {}, pmid = {37047667}, issn = {1422-0067}, support = {R21 DE028715/DE/NIDCR NIH HHS/United States ; R01 DE029709/DE/NIDCR NIH HHS/United States ; R15 DE027851/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; *Streptococcus sanguis ; Streptococcus mutans ; Biofilms ; Mouth/microbiology ; Glucans/pharmacology ; *Dental Caries ; }, abstract = {This study probed in vitro the mechanisms of competition/coexistence between Streptococcus sanguinis (known for being correlated with health in the oral cavity) and Streptococcus mutans (responsible for aciduric oral environment and formation of caries) by means of quantitative Raman spectroscopy and imaging. In situ Raman assessments of live bacterial culture/coculture focusing on biofilm exopolysaccharides supported the hypothesis that both species engaged in antagonistic interactions. Experiments of simultaneous colonization always resulted in coexistence, but they also revealed fundamental alterations of the biofilm with respect to their water-insoluble glucan structure. Raman spectra (collected at fixed time but different bacterial ratios) showed clear changes in chemical bonds in glucans, which pointed to an action by Streptococcus sanguinis to discontinue the impermeability of the biofilm constructed by Streptococcus mutans. The concurrent effects of glycosidic bond cleavage in water-insoluble α - 1,3-glucan and oxidation at various sites in glucans' molecular chains supported the hypothesis that secretion of oxygen radicals was the main "chemical weapon" used by Streptococcus sanguinis in coculture.}, } @article {pmid37047479, year = {2023}, author = {Chen, T and Wang, S and Niu, H and Yang, G and Wang, S and Wang, Y and Zhou, C and Yu, B and Yang, P and Sun, W and Liu, D and Ying, H and Chen, Y}, title = {Biofilm-Based Biocatalysis for Galactooligosaccharides Production by the Surface Display of β-Galactosidase in Pichia pastoris.}, journal = {International journal of molecular sciences}, volume = {24}, number = {7}, pages = {}, pmid = {37047479}, issn = {1422-0067}, support = {2022YFC2105400//the National Key R&D Program of China/ ; 2021YFC2101100//the National Key R&D Program of China/ ; 22178176//the National Natural Science Foundation of China/ ; 2018YFB1501705//the National Key Research and Development Program of China/ ; 21636003//the key program of the National Natural Science Foundation of China/ ; IRT_14R28//the Program for Changjiang Scholars and Innovative Research Team in University/ ; ZDYF20200220//Key Research and Development Program of Nanjing Jiangbei New Area/ ; BE2019001//Key R & D plan of Jiangsu Province/ ; BK20220334//Youth Fund of Natural Science Foundation of Jiangsu Province/ ; 22208157//the National Natural Science Foundation of China/ ; }, mesh = {Biocatalysis ; *Pichia/genetics/metabolism ; beta-Galactosidase/genetics/metabolism ; *Saccharomycetales/metabolism ; Fermentation ; Recombinant Proteins/metabolism ; }, abstract = {Galactooligosaccharides (GOS) are one of the most important functional oligosaccharide prebiotics. The surface display of enzymes was considered one of the most excellent strategies to obtain these products. However, a rough industrial environment would affect the biocatalytic process. The catalytic process could be efficiently improved using biofilm-based fermentation with high resistance and activity. Therefore, the combination of the surface display of β-galactosidase and biofilm formation in Pichia pastoris was constructed. The results showed that the catalytic conversion rate of GOS was up to 50.3% with the maximum enzyme activity of 5125 U/g by screening the anchorin, and the number of the continuous catalysis batches was up to 23 times. Thus, surface display based on biofilm-immobilized fermentation integrated catalysis and growth was a co-culture system, such that a dynamic equilibrium in the consolidated integrative process was achieved. This study provides the basis for developing biofilm-based surface display methods in P. pastoris during biochemical production processes.}, } @article {pmid37047147, year = {2023}, author = {Wolfson, G and Sionov, RV and Smoum, R and Korem, M and Polacheck, I and Steinberg, D}, title = {Anti-Bacterial and Anti-Biofilm Activities of Anandamide against the Cariogenic Streptococcus mutans.}, journal = {International journal of molecular sciences}, volume = {24}, number = {7}, pages = {}, pmid = {37047147}, issn = {1422-0067}, mesh = {Humans ; *Streptococcus mutans ; Endocannabinoids/metabolism ; *Dental Caries/prevention & control ; Biofilms ; Anti-Bacterial Agents/pharmacology/metabolism ; }, abstract = {Streptococcus mutans is a cariogenic bacterium in the oral cavity involved in plaque formation and dental caries. The endocannabinoid anandamide (AEA), a naturally occurring bioactive lipid, has been shown to have anti-bacterial and anti-biofilm activities against Staphylococcus aureus. We aimed here to study its effects on S. mutans viability, biofilm formation and extracellular polysaccharide substance (EPS) production. S. mutans were cultivated in the absence or presence of various concentrations of AEA, and the planktonic growth was followed by changes in optical density (OD) and colony-forming units (CFU). The resulting biofilms were examined by MTT metabolic assay, Crystal Violet (CV) staining, spinning disk confocal microscopy (SDCM) and high-resolution scanning electron microscopy (HR-SEM). The EPS production was determined by Congo Red and fluorescent dextran staining. Membrane potential and membrane permeability were determined by diethyloxacarbocyanine iodide (DiOC2(3)) and SYTO 9/propidium iodide (PI) staining, respectively, using flow cytometry. We observed that AEA was bactericidal to S. mutans at 12.5 µg/mL and prevented biofilm formation at the same concentration. AEA reduced the biofilm thickness and biomass with concomitant reduction in total EPS production, although there was a net increase in EPS per bacterium. Preformed biofilms were significantly affected at 50 µg/mL AEA. We further show that AEA increased the membrane permeability and induced membrane hyperpolarization of these bacteria. AEA caused S. mutans to become elongated at the minimum inhibitory concentration (MIC). Gene expression studies showed a significant increase in the cell division gene ftsZ. The concentrations of AEA needed for the anti-bacterial effects were below the cytotoxic concentration for normal Vero epithelial cells. Altogether, our data show that AEA has anti-bacterial and anti-biofilm activities against S. mutans and may have a potential role in preventing biofilms as a therapeutic measure.}, } @article {pmid37044235, year = {2023}, author = {Delik, E and Eroğlu, B and Çolak, ÇY and Özçelik, AT and Tefon Öztürk, BE}, title = {Alterations of Growth, Biofilm-Forming, and Gene Expression of Bordetella pertussis by Antibiotics at Sub-Minimal Inhibitory Concentrations.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104058}, doi = {10.1016/j.resmic.2023.104058}, pmid = {37044235}, issn = {1769-7123}, abstract = {Bordetella pertussis is the primary agent of the acute respiratory disease pertussis. It has been reported that the disease has recently become more common, especially in adults and adolescents, and adaptation of the pathogen is thought to have an important influence on the recurrence of the disease. This study aims to determine the effect of erythromycin, azithromycin, and trimethoprim-sulfamethoxazole used in the treatment of pertussis on the virulence gene expressions (prn, ptxS1, fhaB), biofilm-forming and growth of B. pertussis. In this study, the minimal inhibitory concentration (MIC) values of azithromycin and erythromycin in B. pertussis local strain Saadet were determined to be 0.09 μg/mL and 0.3 μg/mL, respectively. However, the Tohama-I and Saadet strains were resistant to trimethoprim-sulfamethoxazole (MIC>32 μg/mL). The biofilm-forming of the Saadet strain decreased with the increase in antibiotic doses. It was observed that 1/32MIC erythromycin and 1/32MIC azithromycin upregulated the expression of fhaB in Tohama-I, whereas the expression of ptxS1 and prn significantly decreased in sub-MICs of erythromycin. In the Saadet strain, only ptxS1 was highly expressed at 1/16MIC azithromycin and erythromycin (p>0.05). This is the first study to investigate the effect of sub-MIC antibiotics on the expression of virulence genes and biofilm-forming of B. pertussis.}, } @article {pmid37043980, year = {2023}, author = {Tan, Y and Lin, Q and Yao, J and Zhang, G and Peng, X and Tian, J}, title = {In vitro outcomes of quercetin on Candida albicans planktonic and biofilm cells and in vivo effects on vulvovaginal candidiasis. Evidences of its mechanisms of action.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {114}, number = {}, pages = {154800}, doi = {10.1016/j.phymed.2023.154800}, pmid = {37043980}, issn = {1618-095X}, mesh = {Humans ; Female ; Mice ; Animals ; *Candidiasis, Vulvovaginal/drug therapy/microbiology ; Candida albicans ; Antifungal Agents/pharmacology ; Quercetin/pharmacology ; Plankton ; Biofilms ; }, abstract = {BACKGROUND AND PURPOSE: Candida albicans is a fungus that produces common fungal infection in humans, including vulvovaginal candidiasis (VVC). While quercetin (QC) has potential antifungal activities against C. albicans, studies on the in vivo anti-VVC activity of QC are limited. This study evaluated the antifungal capacity of QC against cultured C. albicans strain SC5314 or in C. albicans-infected mice.

METHODS: Microdilution and XTT reduction assay were used to determine the minimum inhibitory concentration (MIC) and biofilm formation of QC on C. albicans, respectively. Immunofluorescence was performed to detect the anti-invasive capacity of QC upon co-culturing C. albicans with VK2/E6E7 cells. The potential anti-VVC effects of QC were assessed in C. albicans-infected mice with VVC. Further, inflammatory cytokine levels were determined using ELISA. PAS and Papanicolaou staining were used to detect C. albicans cells and polymorphonuclear leukocytes (PMNs) in vaginal tissues. Western blotting and immunohistochemistry were performed to measure the expression of MAPK, ERK, JUN, and P38.

RESULTS: MIC and minimal fungicidal concentration (MFC) of QC for C. albicans were 128 μM and > 512 μM, respectively. QC concentration lower than 128 μM (32-128 μM) could not inhibit C. albicans. QC (16 μM) notably inhibited C. albicans biofilm formation and suppressed the adhesion and invasion of C. albicans to VK2/E6E7 cells. In addition, the pharmacokinetic parameters of orally administered QC in mice showed rapid absorption (approximately 1 h) and slow elimination (approximately 6 h). Oral QC showed an effective protective function against C. albicans infection with no toxic effects a in mouse VVC model. QC significantly reduced IL-1α, TNF-α, IL-22 and IL-23 levels in vaginal lavage solution, inhibited invasive C. albicans and PMN infiltration in vaginal tissue, and effectively protected the integrity of vaginal mucosa.

CONCLUSIONS: The present study showed that QC has rapid oral absorption, slow elimination, good viral distribution, and a lack of toxicity. QC not only inhibited biofilm formation, adhesion, and invasion of C. albicans in vitro, but also ameliorated C. albicans-induced inflammation and protected the integrity of the vaginal mucosa in vivo, suggesting that QC has the potential for the treatment of candidiasis.}, } @article {pmid37042006, year = {2023}, author = {Edris, SN and Hamad, A and Awad, DAB and Sabeq, II}, title = {Prevalence, antibiotic resistance patterns, and biofilm formation ability of Enterobacterales recovered from food of animal origin in Egypt.}, journal = {Veterinary world}, volume = {16}, number = {2}, pages = {403-413}, pmid = {37042006}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: The majority of animal-derived food safety studies have focused on foodborne zoonotic agents; however, members of the opportunistic Enterobacteriaceae (Ops) family are increasingly implicated in foodborne and public health crises due to their robust evolution of acquiring antimicrobial resistance and biofilms, consequently require thorough characterization, particularly in the Egyptian food sector. Therefore, this study aimed to determine the distribution and prevalence of Enterobacteriaceae family members in animal-derived foods, as well as their resistance to important antimicrobials and biofilm-forming potential.

MATERIALS AND METHODS: A total of 274 beef, rabbit meat, chicken meat, egg, butter, and milk samples were investigated for the presence of Enterobacteriaceae. All isolated strains were first recognized using traditional microbiological techniques. Following that, matrix-assisted laser desorption ionization-time of flight mass spectrometry was used to validate the Enterobacteriaceae's identity. The isolated enterobacteria strains were tested on disk diffusion and crystal violet quantitative microtiter plates to determine their antibiotic resistance and capacity to form biofilms.

RESULTS: There have been thirty isolates of Enterobacteriaceae from seven different species and four genera. Out of the three food types, Pseudomonas aeruginosa had the highest prevalence rate (4.1%). With three species, Enterobacter genera had the second-highest prevalence (3.28%) across five different food categories. In four different food types, the Klebsiella genera had the second-highest distribution and third-highest incidence (2.55%). Almost all isolates, except three Proteus mirabilis, showed prominent levels of resistance, particularly to beta-lactam antibiotics. Except for two Enterobacter cloacae and three P. mirabilis isolates, all isolates were classified as multidrug-resistant (MDR) orextensively multidrug-resistant (XDR). The multiple antibiotic resistance index (MARI) of the majority of isolates dropped between 0.273 and 0.727. The highest MARI was conferred by Klebsiella pneumoniae, at 0.727. Overall, 83.33% of the isolates had strong biofilm capacity, while only 16.67% exhibited moderate capacity.

CONCLUSION: The MDR, XDR, and strong biofilm indicators confirmed in 83.33% of the currently tested Enterobacteriaceae from animal-derived foods suggest that, if not addressed, there may be rising risks to Egypt's economy and public health.}, } @article {pmid37041833, year = {2023}, author = {Ibraheim, HK and Madhi, KS and Baqer, GK and Gharban, HAJ}, title = {Effectiveness of raw bacteriocin produced from lactic acid bacteria on biofilm of methicillin-resistant Staphylococcus aureus.}, journal = {Veterinary world}, volume = {16}, number = {3}, pages = {491-499}, pmid = {37041833}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Probiotics are proven beneficial to health since they enhance immunity against dangerous pathogens and increase resistance to illness. Bacteriocin produced by lactic acid bacteria (LAB), demonstrates a broad inhibitory spectrum and therapeutic potential. This study aimed to isolate LAB-producing bacteriocin and investigate the effect of crude bacteriocin on biofilm from methicillin-resistant Staphylococcus aureus (MRSA).

MATERIALS AND METHODS: This study used randomly collected 80 white soft local cheeses (40 each from cows and sheep) from different supermarkets in Basrah Province. The obtained samples were cultured and the bacterial suspension of S. aureus was prepared at 1.5 × 10[8] cells/mL. The crude bacteriocin extracted from LAB was obtained, and the tube was dried and inverted to detect the biofilm loss at the bottom.

RESULTS: There were 67 (83.75%) LAB isolates. Among 40 milk samples collected directly and indirectly, there were 36 (83.33%). Staphylococcus aureus isolates based on conventional bacteriological analysis and biochemical tests. Molecular testing was conducted to identify LAB and MRSA. Depending on genotypic results, the effect of white soft local cheese (cows and sheep) and the amplification results of the 16S rRNA gene were detected in 46 LAB isolates from white soft local cheese from cows and sheep. Based on the molecular identification of the mecA, results on Staphylococcus determined that only 2 of 36 isolates of S. aureus carried the mecA. Moreover, there were 26 (86.66%) isolates (MRSA) from samples of raw milk from local markets and subclinical mastitis in cows. The ability of LAB isolates was tested. The effects of bacteriocin production on preventing biofilm growth and formation were investigated. Results demonstrated that bacteriocin has high activity. Microtiter plates applied to investigate the ability of S. aureus to produce biofilms revealed that all isolates were either weak or moderate biofilm producers, with neither non-biofilm nor strong biofilm producers found among the tested isolates.

CONCLUSION: Lactic acid bacteria demonstrate a high ability to produce bacteriocin. Crude bacteriocin from LAB has a restrictive effect on biofilms produced by MRSA; thus, it can be used to reduce the pathogenicity of this bacterium.}, } @article {pmid37041795, year = {2022}, author = {Asnaashari, M and Mehrabinia, P and Yadegari, Z and Hoseini, H and Sadafi, M and Shojaeian, S}, title = {Evaluation of Antibacterial Effects of Cold Atmospheric Plasma, Calcium Hydroxide, and Triple Antibiotic Paste on Enterococcus faecalis Biofilm in the Root Canal System: An In Vitro Study.}, journal = {Journal of lasers in medical sciences}, volume = {13}, number = {}, pages = {e50}, pmid = {37041795}, issn = {2008-9783}, abstract = {Introduction: One of the essential factors in successful endodontic therapy is the effective cleaning and disinfection of the root canal. This study aimed to determine the effect of cold plasma on infected root canals with Enterococcus faecalis and compare its antibacterial effect with the conventional medicaments in vitro. Methods: Sixty-tree single-root teeth were extracted. Canals were cleaned and shaped. Ten teeth were selected as the negative control randomly. The rest of the teeth were incubated at 37°C for 21 days to form E. faecalis biofilm. The specimens were divided into six groups; each group had 10 teeth. In group 1 (the positive control group of calcium hydroxide and triple antibiotic paste [TAP]), methylcellulose was placed in the root canal; in group 2, calcium hydroxide was placed in the root canal for 12 days; in group 3, 10 mg/mL of TAP was placed in the root canal for 12 days; in group 4, helium/oxygen plasma jet was used for 10 minutes. Group 5 was considered as a positive control of plasma, and group 6 was the negative control. After treatment, F4 Pro-Taper rotary file was used to collect root canal microbial biofilms. Bacterial suspensions were serially diluted, and the percentage of growth reduction for each group was obtained by dividing the logarithm of CFU/mL of each group by CFU/mL of the control of the same group. Results: The CFU/mL of TAP and plasma-treated samples was significantly lower than that of the control groups; however, there were no significant differences between the control group and the samples treated by calcium hydroxide. The most percentage of CFU reduction was in the TAP-treated group compared with plasma and calcium hydroxide-treated groups. Conclusion: The application of cold plasma effectively inhibited the growth of E. faecalis and reduced bacterial biofilm. Also, in the present study, 10 mg/mL of TAP caused the complete elimination of E. faecalis. Calcium hydroxide had the most negligible effect on E. faecalis biofilm elimination.}, } @article {pmid37041658, year = {2023}, author = {}, title = {Correction to "Azospirillum baldaniorum Sp245 exploits Pseudomonas fluorescens A506 biofilm to overgrow in dual-species macrocolonies".}, journal = {Environmental microbiology}, volume = {25}, number = {5}, pages = {1068}, doi = {10.1111/1462-2920.16383}, pmid = {37041658}, issn = {1462-2920}, } @article {pmid37036347, year = {2023}, author = {Lewis, AM and Willard, DJ and H Manesh, MJ and Sivabalasarma, S and Albers, SV and Kelly, RM}, title = {Stay or Go: Sulfolobales Biofilm Dispersal Is Dependent on a Bifunctional VapB Antitoxin.}, journal = {mBio}, volume = {14}, number = {2}, pages = {e0005323}, pmid = {37036347}, issn = {2150-7511}, support = {2T32GM008776/NH/NIH HHS/United States ; }, mesh = {*Antitoxins/metabolism ; Bacterial Proteins/metabolism ; *Bacterial Toxins/metabolism ; Sulfolobales ; Biofilms ; }, abstract = {A type II VapB14 antitoxin regulates biofilm dispersal in the archaeal thermoacidophile Sulfolobus acidocaldarius through traditional toxin neutralization but also through noncanonical transcriptional regulation. Type II VapC toxins are ribonucleases that are neutralized by their proteinaceous cognate type II VapB antitoxin. VapB antitoxins have a flexible tail at their C terminus that covers the toxin's active site, neutralizing its activity. VapB antitoxins also have a DNA-binding domain at their N terminus that allows them to autorepress not only their own promoters but also distal targets. VapB14 antitoxin gene deletion in S. acidocaldarius stunted biofilm and planktonic growth and increased motility structures (archaella). Conversely, planktonic cells were devoid of archaella in the ΔvapC14 cognate toxin mutant. VapB14 is highly conserved at both the nucleotide and amino acid levels across the Sulfolobales, extremely unusual for type II antitoxins, which are typically acquired through horizontal gene transfer. Furthermore, homologs of VapB14 are found across the Crenarchaeota, in some Euryarchaeota, and even bacteria. S. acidocaldarius vapB14 and its homolog in the thermoacidophile Metallosphaera sedula (Msed_0871) were both upregulated in biofilm cells, supporting the role of the antitoxin in biofilm regulation. In several Sulfolobales species, including M. sedula, homologs of vapB14 and vapC14 are not colocalized. Strikingly, Sulfuracidifex tepidarius has an unpaired VapB14 homolog and lacks a cognate VapC14, illustrating the toxin-independent conservation of the VapB14 antitoxin. The findings here suggest that a stand-alone VapB-type antitoxin was the product of selective evolutionary pressure to influence biofilm formation in these archaea, a vital microbial community behavior. IMPORTANCE Biofilms allow microbes to resist a multitude of stresses and stay proximate to vital nutrients. The mechanisms of entering and leaving a biofilm are highly regulated to ensure microbial survival, but are not yet well described in archaea. Here, a VapBC type II toxin-antitoxin system in the thermoacidophilic archaeon Sulfolobus acidocaldarius was shown to control biofilm dispersal through a multifaceted regulation of the archaeal motility structure, the archaellum. The VapC14 toxin degrades an RNA that causes an increase in archaella and swimming. The VapB14 antitoxin decreases archaella and biofilm dispersal by binding the VapC14 toxin and neutralizing its activity, while also repressing the archaellum genes. VapB14-like antitoxins are highly conserved across the Sulfolobales and respond similarly to biofilm growth. In fact, VapB14-like antitoxins are also found in other archaea, and even in bacteria, indicating an evolutionary pressure to maintain this protein and its role in biofilm formation.}, } @article {pmid37035538, year = {2023}, author = {Bisso, BN and Makuété, AL and Tsopmene, JU and Dzoyem, JP}, title = {Biofilm Formation and Phospholipase and Proteinase Production in Cryptococcus neoformans Clinical Isolates and Susceptibility towards Some Bioactive Natural Products.}, journal = {TheScientificWorldJournal}, volume = {2023}, number = {}, pages = {6080489}, pmid = {37035538}, issn = {1537-744X}, mesh = {Humans ; Antifungal Agents/pharmacology ; *Cryptococcus neoformans ; Peptide Hydrolases ; Thymol ; Phospholipases ; *Cryptococcosis/drug therapy/epidemiology/microbiology ; Microbial Sensitivity Tests ; Virulence Factors ; Biofilms ; }, abstract = {BACKGROUND: Cryptococcosis is one of the most common fungal infections in immunocompromised patients, which is caused by Cryptococcus neoformans. However, relatively little is known about the virulence factors of C. neoformans and the incidence of antifungal drug resistance in C. neoformans is rapidly increasing. This study was undertaken to investigate the virulence factors in C. neoformans, thymol, curcumin, piperine, gallic acid, eugenol, and plumbagin for their potential antimicrobial activity against C. neoformans.

METHODS: The production of phospholipase and proteinase was detected using standard methods. Biofilm formation was determined using the microtiter plate method. The broth microdilution method was used to determine the antifungal activity. The antibiofilm activity was assessed using the safranin staining method.

RESULTS: All isolates of C. neoformans produced biofilms with optical density values ranging from 0.16 to 0.89. A majority of C. neoformans isolates that were tested exhibited strong phospholipase (7/8) and proteinase (5/8) production. Plumbagin (with minimum inhibitory concentration values ranging from 4 to 16 μg/mL) showed the highest antifungal activity followed by thymol (with minimum biofilm inhibitory concentration values ranging from 8 to 64 μg/mL). In addition, plumbagin showed the highest antibiofilm activity with minimum biofilm inhibitory concentration and minimum biofilm eradication concentration values ranging from 4 to 16 μg/mL and 32 to 256 μg/mL, respectively.

CONCLUSION: Plumbagin, compared to other natural products studied, was the most efficient in terms of antifungal and antibiofilm activities. Hence, plumbagin could be used in combination with antifungals for the development of new anticryptococcal drugs.}, } @article {pmid37034999, year = {2023}, author = {Xiong, Y and Liu, S and Zheng, J and Chen, J and Wen, Z and Deng, X and Bai, B and Li, D and Yu, Z and Han, S and Liu, X and Li, P}, title = {Cinacalcet exhibits rapid bactericidal and efficient anti-biofilm activities against multidrug-resistant Gram-positive pathogens.}, journal = {iScience}, volume = {26}, number = {4}, pages = {106378}, pmid = {37034999}, issn = {2589-0042}, abstract = {Infections caused by Gram-positive bacteria pose a serious threat to global public health. Drug resistance, dormant persister cells, and biofilm formation are the key challenges affecting the efficacy of antibiotics against Gram-positive bacterial infections. In this study, cinacalcet exhibited good inhibitory activity against multidrug-resistant Gram-positive bacteria, with minimum inhibitory concentrations (MICs) ranging from 3.13 μg/mL to 25 μg/mL. Cinacalcet displayed more rapid and stronger bactericidal activity against planktonic and persister cells of Staphylococcus aureus and Enterococcus faecalis compared with the antibiotics vancomycin or ampicillin, as well as potent inhibition and eradication of mature biofilms of methicillin-resistant S. aureus (MRSA) and linezolid-resistant E. faecalis (LRE). In addition, the robust antibacterial activity was demonstrated in vivo by a pneumonia infection model and a biofilm formation and deep-seated infection model. Collectively, these findings indicate that cinacalcet may be a promising new candidate antibiotic to combat infections caused by multidrug-resistant Gram-positive pathogens.}, } @article {pmid37031894, year = {2023}, author = {Castelo-Branco, DSCM and Aguiar, L and Guedes, GMM and Pereira-Neto, WA and Cordeiro, RA and Brilhante, RSN and Sidrim, JJC and Rocha, MFG}, title = {Standardization of in vitro dual-species biofilms of Staphylococcus pseudintermedius and Malassezia pachydermatis: a strategy to establish an ex vivo biofilm model.}, journal = {Journal of microbiological methods}, volume = {208}, number = {}, pages = {106721}, doi = {10.1016/j.mimet.2023.106721}, pmid = {37031894}, issn = {1872-8359}, mesh = {Animals ; Swine ; *Staphylococcus ; Biofilms ; *Malassezia ; Reference Standards ; }, abstract = {Ex vivo experiments have been performed aiming at mimicking in vivo environments. The main aim of this research was to standardize in vitro dual-species biofilm formation by Staphylococcus pseudintermedius and Malassezia pachydermatis as a strategy to establish an ex vivo biofilm model. Initially, the in vitro formation of biofilms in co-culture was established, using YPD medium, inoculum turbidity of 0.5 on the McFarland scale and maturation periods of 96 h for M. pachydermatis and 48 h for S. pseudintermedius. Subsequently, biofilms were formed on porcine skin using the same conditions, under which a greater number of cells/ml was observed in in vitro dual-species than in in vitro mono-species biofilms. Furthermore, ex vivo biofilm images demonstrated the formation of a highly structured biofilm with the presence of cocci and yeasts surrounded by the matrix. Thus, these conditions optimized the growth of both microorganisms within biofilms in vitro and ex vivo.}, } @article {pmid37031284, year = {2023}, author = {Vasconcelos, L and Aburjaile, F and Andrade, L and Cancio, AF and Seyffert, N and Aguiar, ERGR and Ristow, P}, title = {Genomic insights into the c-di-GMP signaling and biofilm development in the saprophytic spirochete Leptospira biflexa.}, journal = {Archives of microbiology}, volume = {205}, number = {5}, pages = {180}, pmid = {37031284}, issn = {1432-072X}, support = {Nº 266/2018, BOL0501/2018//Fundação de Amparo à Pesquisa do Estado da Bahia/ ; BOL1963/2019, Request n° 4756/2019//Fundação de Amparo à Pesquisa do Estado da Bahia/ ; 425526/2016-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 425526/2016-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 425526/2016-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 425526/2016-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; Finance Code 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; Finance Code 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 23038.000776/2017-54//National Institute of Science & Technology in Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), Brazil/ ; 23038.000776/2017-54//National Institute of Science & Technology in Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), Brazil/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Spirochaetales/metabolism ; *Escherichia coli Proteins/genetics ; Bacteria/metabolism ; *Leptospira/genetics/metabolism ; Genomics ; Biofilms ; Gene Expression Regulation, Bacterial ; }, abstract = {C-di-GMP is a bacterial second messenger with central role in biofilm formation. Spirochete bacteria from Leptospira genus present a wide diversity, with species of medical importance and environmental species, named as saprophytic. Leptospira form biofilms in the rat's reservoir kidneys and in the environment. Here, we performed genomic analyses to identify enzymatic and effector c-di-GMP proteins in the saprophytic biofilm-forming species Leptospira biflexa serovar Patoc. We identified 40 proteins through local alignments. Amongst them, 16 proteins are potentially functional diguanylate cyclases, phosphodiesterases, or hybrid proteins. We also identified nine effectors, including PilZ proteins. Enrichment analyses suggested that c-di-GMP interacts with cAMP signaling system, CsrA system, and flagella assembly regulation during biofilm development of L. biflexa. Finally, we identified eight proteins in the pathogen Leptospira interrogans serovar Copenhageni that share high similarity with L. biflexa c-di-GMP-related proteins. This work revealed proteins related to c-di-GMP turnover and cellular response in Leptospira and their potential roles during biofilm development.}, } @article {pmid37030463, year = {2023}, author = {Bains, A and Sharma, P and Kaur, S and Yadav, R and Kumar, A and Sridhar, K and Chawla, P and Sharma, M}, title = {Gum arabic/guar gum stabilized Hydnocarpus wightiana oil nanohydrogel: Characterization, antimicrobial, anti-inflammatory, and anti-biofilm activities.}, journal = {International journal of biological macromolecules}, volume = {239}, number = {}, pages = {124341}, doi = {10.1016/j.ijbiomac.2023.124341}, pmid = {37030463}, issn = {1879-0003}, mesh = {*Gum Arabic/chemistry ; Plant Gums/chemistry ; *Anti-Infective Agents/pharmacology ; Anti-Bacterial Agents/pharmacology/chemistry ; Escherichia coli ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Hydnocarpus wightiana oil has proven to inhibit the growth of pathogenic microorganisms; however, the raw form is highly susceptible to oxidation, and thus it becomes toxic when uptake is in high amounts. Therefore, to minimize the deterioration, we formulated Hydnocarpus wightiana oil-based nanohydrogel and studied its characteristics as well biological activity. The low energy-assisted hydrogel was formulated by including gelling agent, connective linker, and cross-linker and it resulted in internal micellar polymerization of the milky white emulsion. The oil showed the presence of octanoic acid, n-tetradecane, methyl 11-(2-cyclopenten-1-yl) undecanoate (methyl hydnocarpate), 13-(2-cyclopenten-1-yl) tridecanoic acid (methyl chaulmoograte), and 10,13-eicosadienoic acid. The amount of caffeic acid was 0.0636 mg/g, which was higher than the amount of gallic acid (0.0076 mg/g) in the samples. The formulated nanohydrogel showed an average droplet size of 103.6 nm with a surface charge of -17.6 mV. The minimal inhibitory bactericidal, and fungicidal concentrations of nanohydrogel against pathogenic bacteria and fungi were ranging from 0.78 to 1.56 μl/mL with 70.29-83.62 % antibiofilm activity. Also, nanohydrogel showed a significantly (p < 0.05) higher killing rate for Escherichia coli (7.89 log CFU/mL) than Staphylococcus aureus (7.81 log CFU/mL) with comparable anti-inflammatory activity than commercial standard (49.28-84.56 %). Therefore, it can be concluded that being hydrophobic, and having the capability of target-specific drug absorption as well as biocompatibility nanohydrogels can be utilized to cure various pathogenic microbial infections.}, } @article {pmid37030196, year = {2023}, author = {Sanchez-Huerta, C and Medina, JS and Wang, C and Fortunato, L and Hong, PY}, title = {Understanding the role of sorption and biodegradation in the removal of organic micropollutants by membrane aerated biofilm reactor (MABR) with different biofilm thickness.}, journal = {Water research}, volume = {236}, number = {}, pages = {119935}, doi = {10.1016/j.watres.2023.119935}, pmid = {37030196}, issn = {1879-2448}, mesh = {*Waste Disposal, Fluid ; *Acetaminophen ; Bioreactors/microbiology ; Biofilms ; Biodegradation, Environmental ; }, abstract = {The role of sorption and biodegradation in a membrane aerated biofilm reactor (MABR) were investigated for the removal of 10 organic micropollutants (OMPs) including endocrine disruptors and pharmaceutical active compounds. The influence of the biofilm thickness on the mechanisms of removal was analyzed via kinetic test at three different stages. At all biofilm stages, biodegradation was demonstrated to dominate the removal of selected OMPs. Higher OMPs rates of removal via biodegradation (Kbiol) were achieved when biofilm increased its thickness from (stage T1) 0.26 mm, to (stage T2) 0.58 mm and (stage T3) 1.03 mm. At stage T1 of biofilm, heterotrophs contribute predominantly to OMPs degradation. Hydrophilic compounds removal (i.e., acetaminophen) continue to be driven by heterotrophic bacteria at the next stages of biofilm thickness. However, for medium hydrophobic neutral and charged OMPs, the combined action of heterotrophic and enriched nitrifying activity at stages T2 and T3 enhanced the overall removal. A degradation pathway based on heterotrophic activity for acetaminophen and combined action of nitrifiers-heterotrophs for estrone was proposed based on identified metabolites. Although biodegradation dominated the removal of most OMPs, sorption was also observed to be essential in the removal of biologically recalcitrant and lipophilic compounds like triclosan. Furthermore, sorption capacity of apolar compound was enhanced as the biofilm thickness grew and increased in EPS protein fraction. Microbial analysis confirmed the higher abundance of nitrifying and denitrifying activity at stage T3 of biofilm, which not only facilitated near complete ammonium removal but also enhanced degradation of OMPs.}, } @article {pmid37029837, year = {2023}, author = {Mirzaei, B and Ebrahimi, A and Keshavarzi, S and Hydarzadeh, S and Badmasti, F and Dadar, M and Moradi, N}, title = {Antibiotic Susceptibility, Biofilm-Forming Ability, and Prevalence of Extended-Spectrum Beta-Lactamase (ESBL)- and Biofilm-Associated Genes Among Klebsiella pneumoniae Isolates from Hospitalized Patients in Northwest of Iran.}, journal = {Current microbiology}, volume = {80}, number = {5}, pages = {175}, pmid = {37029837}, issn = {1432-0991}, mesh = {Humans ; *Klebsiella pneumoniae/genetics ; *beta-Lactamases/genetics ; Prevalence ; Iran/epidemiology ; Escherichia coli/genetics ; Anti-Bacterial Agents/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Klebsiella pneumoniae is an opportunistic bacterium, which is globally recognized for its high prevalence and antimicrobial resistance (AMR). Biofilm-forming capability, susceptibility testing, and phenotypic confirmatory test for extended-spectrum beta-lactamase (ESBL)-producing isolate recognition of 104 K. pneumoniae isolates were performed according to the Clinical Laboratory Standard Institute (CLSI) guidelines. The prevalence of ESBL-associated genes bla-VIM, bla-NDM, and bla-OXA-48, as well as biofilm-associated genes luxS, fimH1, wza, and mrkD, was determined by multiplex PCR. The highest resistance rate was against ampicillin (100.0%). Among the 104 K. pneumoniae isolates, 52 (50.0%) and 31 (29.8%) isolates were determined as multi- and extensively drug resistant (MDR, XDR), respectively. Moreover, 21 (40.4%) isolates were determined as ESBL producing. Among 50 biofilm-producing K. pneumoniae isolates, 7 (14.0%), 15 (30.0%), and 28 (56.0%) isolates exhibited high, moderate, and weak levels of biofilm formation, respectively. A number of 41 (78.8%) isolates were susceptible to colistin, and 10 (19.2%) were resistant. AMR was significantly higher (P < 0.05) in the biofilm-forming isolates compared with non-biofilm formers.}, } @article {pmid37028211, year = {2023}, author = {Bydalek, F and Webster, G and Barden, R and Weightman, AJ and Kasprzyk-Hordern, B and Wenk, J}, title = {Microplastic biofilm, associated pathogen and antimicrobial resistance dynamics through a wastewater treatment process incorporating a constructed wetland.}, journal = {Water research}, volume = {235}, number = {}, pages = {119936}, doi = {10.1016/j.watres.2023.119936}, pmid = {37028211}, issn = {1879-2448}, mesh = {Humans ; *Wastewater ; Genes, Bacterial ; Microplastics ; Plastics ; Anti-Bacterial Agents ; Sewage ; Wetlands ; RNA, Ribosomal, 16S/genetics ; Drug Resistance, Bacterial/genetics ; Bacteria/genetics ; Biofilms ; *Water Purification ; Water ; }, abstract = {Microplastics in wastewater are colonized by biofilms containing pathogens and antimicrobial resistance (AMR) genes that can be exported into receiving water bodies. This study investigated establishment and changes in microplastic-associated biofilm and AMR during a conventional full-scale 2100 population equivalent wastewater treatment process combined with a free water surface polishing constructed wetland. Sequential microplastic colonization experiments were conducted at different stages of the wastewater treatment process, including in raw sewage, treated effluent and the constructed wetland. Two scenarios were tested in which the constructed wetland served as either (i) a polishing step or (ii) as primary recipient of sewage inoculated microplastics. Bacterial 16S rRNA gene sequencing was carried out for qualitative bacterial community analysis. qPCR was applied for quantitative analysis of AMR genes (sul1, ermB, tetW, intiI1), bacterial biomass (16S rRNA) and a human fecal marker (HF183). Microbial diversity on microplastics increased with incubation time. The initial sewage-derived biofilm composition changed more significantly in the wastewater effluent compared to the constructed wetland. Pathogen and AMR load decreased by up to two orders of magnitude after coupled conventional and constructed wetland treatment, while less impact was observed when sewage-inoculated microplastic material was directly transferred into the constructed wetland. Aeromonas, Klebsiella, and Streptococcus were key pathogenic genera correlated with AMR in microplastic-associated biofilms. Despite decreasing trends on human pathogens and AMR load along the treatment process, microplastic-associated biofilms were a considerable potential hotspot for AMR (intI1 gene) and accommodated Cyanobacteria and fish pathogens.}, } @article {pmid37027924, year = {2023}, author = {Zhang, J and Shao, Y and Li, Z and Han, G and Jing, X and Wang, N and Xu, J and Chen, G}, title = {Characteristics analysis of plastisphere biofilm and effect of aging products on nitrogen metabolizing flora in microcosm wetlands experiment.}, journal = {Journal of hazardous materials}, volume = {452}, number = {}, pages = {131336}, doi = {10.1016/j.jhazmat.2023.131336}, pmid = {37027924}, issn = {1873-3336}, mesh = {*Plastics ; Wetlands ; Nitrogen ; *Microbiota ; Polyethylene ; Water ; Biofilms ; }, abstract = {The marsh, a significant terrestrial ecosystem, has steadily developed the capacity to act as a microplastics collection place (MPs). Here, 180 days of exposure to three different polymer kinds of plastics: polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC), were conducted in miniature wetlands (CWs). Water contact angle (WCA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and High-throughput sequencing were used to study the succession of microbial community structure and function on MPs after 0, 90, and 180 days of exposure. The results showed that different polymers were degrading and aging differing degrees; PVC contained new functional groups with the symbols -CC-, -CO-, and -OH, while PE had the biggest range of contact angles (74.0-45.5°). Bacteria colonization was discovered on plastic surfaces, and as time went on, it became increasingly evident that the surfaces' composition had altered, and their hydrophobicity had diminished. The plastisphere's microbial community structure as well as water nitrification and denitrification were altered by MPs. In general, our study created a vertical flow-built wetland environment, monitored the impacts of plastic aging and breakdown products on nitrogen metabolizing microorganisms in wetland water, and offered a reliable site for the screening of plastic-degrading bacteria.}, } @article {pmid37025362, year = {2023}, author = {Alangari, A and Mateen, A and Alqahtani, MS and Shahid, M and Syed, R and Shaik, MR and Khan, M and Adil, SF and Kuniyil, M}, title = {Antimicrobial, anticancer, and biofilm inhibition studies of highly reduced graphene oxide (HRG): In vitro and in silico analysis.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1149588}, pmid = {37025362}, issn = {2296-4185}, abstract = {Background: Bacterial infections and cancers may cause various acute or chronic diseases, which have become serious global health issues. This requires suitable alternatives involving novel and efficient materials to replace ineffective existing therapies. In this regard, graphene composites are being continuously explored for a variety of purposes, including biomedical applications, due to their remarkable properties. Methods: Herein, we explore, in-vitro, the different biological properties of highly reduced graphene oxide (HRG), including anti-cancer, anti-bacterial, and anti-biofilm properties. Furthermore, to analyze the interactions of graphene with proteins of microbes, in silico docking analysis was also carried out. To do this, HRG was prepared using graphene oxide as a precursor, which was further chemically reduced to obtain the final product. The as-prepared HRG was characterized using different types of microscopic and spectroscopic techniques. Results: The HRG revealed significant cytotoxic ability, using a dose-dependent anti-cell proliferation approach, which substantially killed human breast cancer cells (MCF-7) with IC50 of 29.51 ± 2.68 μg/mL. The HRG demonstrated efficient biological properties, i.e., even at low concentrations, HRG exhibited efficient anti-microbial properties against a variety of microorganisms. Among the different strains, Gram-positive bacteria, such as B. subtilis, MRSA, and S. aureus are more sensitive to HRG compared to Gram-negative bacteria. The bactericidal properties of HRG are almost similar to a commercially available effective antibiotic (ampicillin). To evaluate the efficacy of HRG against bacterial biofilms, Pseudomonas aeruginosa and MRSA were applied, and the results were compared with gentamycin and ampicillin, which are commonly applied standard antibiotics. Notably, HRG demonstrated high inhibition (94.23%) against P.aeruginosa, with lower MIC (50 μg/mL) and IC50 (26.53 μg/mL) values, whereas ampicillin and gentamicin showed similar inhibition (90.45% and 91.31% respectively) but much higher MIC and IC50 values. Conclusion: Therefore, these results reveal the excellent biopotential of HRG in different biomedical applications, including cancer therapy; antimicrobial activity, especially anti-biofilm activity; and other biomedicine-based therapies. Based on the molecular docking results of Binding energy, it is predicted that pelB protein and HRG would form the best stable docking complex, and high hydrogen and hydrophobic interactions between the pelB protein and HRG have been revealed. Therefore, we conclude that HRG could be used as an antibiofilm agent against P. aeruginosa infections.}, } @article {pmid37024695, year = {2023}, author = {Ajetunmobi, OH and Wall, G and Bonifacio, BV and Montelongo-Jauregui, D and Lopez-Ribot, JL}, title = {A 384-Well Microtiter Plate Model for Candida Biofilm Formation and Its Application to High-Throughput Screening.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2658}, number = {}, pages = {53-64}, pmid = {37024695}, issn = {1940-6029}, support = {R33 AI140823/AI/NIAID NIH HHS/United States ; }, mesh = {Humans ; *Candida ; High-Throughput Screening Assays/methods ; Candida albicans ; Antifungal Agents/pharmacology ; *Candidiasis/drug therapy/microbiology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Candidiasis, infections caused by Candida spp., represents one of the most common nosocomial infections afflicting an expanding number of compromised patients. Antifungal therapeutic options are few and show limited efficacy. Moreover, biofilm formation is frequently associated with different manifestations of candidiasis and further complicates therapy. Thus, there is an urgent need for new effective therapeutic agents, particularly those with anti-biofilm activity. Here we describe the development of a novel, simple, fast, economical, and highly reproducible 384-well microtiter plate model for the formation of both Candida albicans and Candida auris biofilms and its application in high-throughput screening (HTS) techniques.}, } @article {pmid37024470, year = {2023}, author = {Young, E and Melaugh, G and Allen, RJ}, title = {Active layer dynamics drives a transition to biofilm fingering.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {17}, pmid = {37024470}, issn = {2055-5008}, support = {682237/ERC_/European Research Council/International ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Biofilms/growth & development ; }, abstract = {The emergence of spatial organisation in biofilm growth is one of the most fundamental topics in biofilm biophysics and microbiology. It has long been known that growing biofilms can adopt smooth or rough interface morphologies, depending on the balance between nutrient supply and microbial growth; this 'fingering' transition has been linked with the average width of the 'active layer' of growing cells at the biofilm interface. Here we use long-time individual-based simulations of growing biofilms to investigate in detail the driving factors behind the biofilm-fingering transition. We show that the transition is associated with dynamical changes in the active layer. Fingering happens when gaps form in the active layer, which can cause local parts of the biofilm interface to pin, or become stationary relative to the moving front. Pinning can be transient or permanent, leading to different biofilm morphologies. By constructing a phase diagram for the transition, we show that the controlling factor is the magnitude of the relative fluctuations in the active layer thickness, rather than the active layer thickness per se. Taken together, our work suggests a central role for active layer dynamics in controlling the pinning of the biofilm interface and hence biofilm morphology.}, } @article {pmid37024282, year = {2023}, author = {Sanford, PA and Miller, KG and Hoyt, KO and Woolston, BM}, title = {Deletion of biofilm synthesis in Eubacterium limosum ATCC 8486 improves handling and transformation efficiency.}, journal = {FEMS microbiology letters}, volume = {370}, number = {}, pages = {}, doi = {10.1093/femsle/fnad030}, pmid = {37024282}, issn = {1574-6968}, mesh = {Humans ; *Extracellular Polymeric Substance Matrix ; *Eubacterium/genetics/metabolism ; Genetic Engineering ; }, abstract = {Eubacterium limosum is an acetogenic bacterium of potential industrial relevance for its ability to efficiently metabolize a range of single carbon compounds. However, extracellular polymeric substance (EPS) produced by the type strain ATCC 8486 is a serious impediment to bioprocessing and genetic engineering. To remove these barriers, here we bioinformatically identified genes involved in EPS biosynthesis, and targeted several of the most promising candidates for inactivation, using a homologous recombination-based approach. Deletion of a single genomic region encoding homologues for epsABC, ptkA, and tmkA resulted in a strain incapable of producing EPS. This strain is significantly easier to handle by pipetting and centrifugation, and retains important wild-type phenotypes including the ability to grow on methanol and carbon dioxide and limited oxygen tolerance. Additionally, this strain is also more genetically tractable with a 2-fold increase in transformation efficiency compared to the highest previous reports. This work advances a simple, rapid protocol for gene knockouts in E. limosum using only the native homologous recombination machinery. These results will hasten the development of this organism as a workhorse for valorization of single carbon substrates, as well as facilitate exploration of its role in the human gut microbiota.}, } @article {pmid37024280, year = {2023}, author = {Carrié, M and Gabelle, JC and Lopes-Ferreira, N and Velly, H}, title = {Enzymatic breakdown of biofilm matrix to allow flow cytometry viability analysis of Clostridium beijerinckii cells.}, journal = {Journal of applied microbiology}, volume = {134}, number = {4}, pages = {}, doi = {10.1093/jambio/lxad062}, pmid = {37024280}, issn = {1365-2672}, mesh = {*Clostridium beijerinckii ; Extracellular Polymeric Substance Matrix ; Polyurethanes ; Flow Cytometry/methods ; Fermentation ; }, abstract = {AIMS: Flow cytometry (FC) is a good way to enumerate the number of viable cells in suspension but is not adapted to mature biofilm analysis. The aim of this study is to investigate the effect of mechanical treatment coupled with enzymatic hydrolysis of biofilm matrix on FC viability analysis of biofilm cells.

METHODS AND RESULTS: Biofilm was grown for 300 h of continuous fermentation on polyurethane foams. Fermentation was stopped, and the biofilm was detached by agitating the foams in PBS buffer with vortex agitation for 2 min. The best enzymatic hydrolysis consisted of sequential use of DNase I and proteinase K incubated for 1 h at 34°C. Biofilm cells detached from polyurethane foams were stained with both propidium iodide (PI) and carboxyfluoresceine diacetate and analyzed by FC. FC analysis performed after vortex agitation revealed the presence of high non-fluorescent events (78.9% ± 3.3%). After enzymatic treatment, a cell population was extracted from background noise and could be observed on FSC-SSC profile. The non-fluorescent events of this cell population decreased drastically to 41.9% ± 6.6%, and the percentage of viable cells was enhanced from 2.6% ± 0.9% to 38.2% ± 4.0% compared to analysis performed after mechanical treatment alone.

CONCLUSIONS: Consequently, protease and nuclease activity are essential to hydrolyze extra polymeric substances prior to FC viability analysis in mature biofilm formed by Clostridium beijerinckii.}, } @article {pmid37022591, year = {2023}, author = {Xin, C and Wang, F and Zhang, J and Zhou, Q and Liu, F and Zhao, C and Song, Z}, title = {Erratum: Secretions from Serratia marcescens Inhibit the Growth and Biofilm Formation of Candida spp. and Cryptococcus neoformans.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {61}, number = {4}, pages = {479}, doi = {10.1007/s12275-023-00037-5}, pmid = {37022591}, issn = {1976-3794}, } @article {pmid37021122, year = {2023}, author = {Guo, L and Dai, H and Feng, S and Zhao, Y}, title = {Contribution of GalU to biofilm formation, motility, antibiotic and serum resistance, and pathogenicity of Salmonella Typhimurium.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1149541}, pmid = {37021122}, issn = {2235-2988}, mesh = {Mice ; Chick Embryo ; Animals ; Virulence/genetics ; *Salmonella typhimurium/genetics ; *Anti-Bacterial Agents ; Chickens ; Biofilms ; Bacterial Proteins/genetics ; }, abstract = {INTRODUCTION: Salmonella Typhimurium is the leading cause of foodborne illnesses in China, resulting in major epidemics and economic losses in recent years. Uridine diphosphate-glucose pyrophosphorylase galU plays an important role in thebiosynthesis of the bacterial envelope. Herein, we evaluated the role of galU in S. Typhimurium infection in chicken.

METHODS: A galU gene mutant was successfully constructed by red homologous recombination technology, and biological characteristics were studied.

RESULTS: The galU mutant strain had a rough phenotype;was defective in biofilm formation, autoagglutination, and motility; exhibited greater sensitivity to most antibiotics, serum, and egg albumen; and had lowercapacity for adhesion to chicken embryo fibroblasts cell line (DF-1). The galU mutant showed dramatically attenuated pathogenicity in chicken embryos (100,000-fold), BALB/c mice (420-fold), and chicks (100-fold).

DISCUSSION: The results imply that galU is an important virulence factor in the pathogenicity of S. Typhimurium, and it may serve a target for the development of veterinary drugs, providing a theoretical basis for the prevention and control of S. Typhimurium.}, } @article {pmid37020863, year = {2023}, author = {Nystedt, HL and Grønlien, KG and Rolfsnes, RR and Winther-Larsen, HC and Løchen Økstad, OA and Tønnesen, HH}, title = {Neutral natural deep eutectic solvents as anti-biofilm agents.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100114}, pmid = {37020863}, issn = {2590-2075}, abstract = {Natural deep eutectic solvents (NADES) are a class of liquids with promising properties as components in pharmaceutical formulations, such as a low toxicity profile, biodegradability and versatility. Recently, their potential use as anti-biofilm agents has been proposed, due to their ability to solubilize and stabilize biological macromolecules. In the current work, the ability to break down biofilm matrix and the biofilm killing activity of three NADES of neutral pH were investigated against Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 9027 biofilms. The tested NADES were choline chloride:xylitol (ChX), choline chloride:glycerol (ChG) and betaine:sucrose (BS). Two of the NADES (ChX and ChG) significantly reduced the number of remaining viable cells of both bacterial species in pre-formed biofilm by 4-6 orders of magnitude, while the average biofilm biomass removal for all NADES was 27-67% (S. aureus) and 34-49% (P. aeruginosa). The tested NADES also inhibited biofilm formation of both bacterial species at concentrations at or below 0.5 x the minimal inhibitory concentration (MIC), possibly in part due to observed restrictions imposed by NADES on planktonic growth. These results demonstrate the potential value of neutral NADES as anti-biofilm agents in future antimicrobial preparations.}, } @article {pmid37019921, year = {2023}, author = {Patkowski, JB and Dahlberg, T and Amin, H and Gahlot, DK and Vijayrajratnam, S and Vogel, JP and Francis, MS and Baker, JL and Andersson, M and Costa, TRD}, title = {The F-pilus biomechanical adaptability accelerates conjugative dissemination of antimicrobial resistance and biofilm formation.}, journal = {Nature communications}, volume = {14}, number = {1}, pages = {1879}, pmid = {37019921}, issn = {2041-1723}, support = {215164/Z/18/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; *Escherichia coli/genetics ; Drug Resistance, Bacterial ; Plasmids ; Biofilms ; Conjugation, Genetic ; }, abstract = {Conjugation is used by bacteria to propagate antimicrobial resistance (AMR) in the environment. Central to this process are widespread conjugative F-pili that establish the connection between donor and recipient cells, thereby facilitating the spread of IncF plasmids among enteropathogenic bacteria. Here, we show that the F-pilus is highly flexible but robust at the same time, properties that increase its resistance to thermochemical and mechanical stresses. By a combination of biophysical and molecular dynamics methods, we establish that the presence of phosphatidylglycerol molecules in the F-pilus contributes to the structural stability of the polymer. Moreover, this structural stability is important for successful delivery of DNA during conjugation and facilitates rapid formation of biofilms in harsh environmental conditions. Thus, our work highlights the importance of F-pilus structural adaptations for the efficient spread of AMR genes in a bacterial population and for the formation of biofilms that protect against the action of antibiotics.}, } @article {pmid37018485, year = {2023}, author = {Park, S and Kumar, S and Maier, CS and Kreth, J and Koley, D}, title = {Simultaneous Chemical Mapping of Live Biofilm Microenvironmental pH and Hydrogen Peroxide in Real Time with a Triple Scanning Electrochemical Microscopy Tip.}, journal = {Analytical chemistry}, volume = {95}, number = {15}, pages = {6332-6340}, doi = {10.1021/acs.analchem.2c05258}, pmid = {37018485}, issn = {1520-6882}, support = {R01 DE027999/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; *Hydrogen Peroxide/metabolism ; Microscopy, Electrochemical, Scanning/methods ; *Dental Plaque ; Ecosystem ; Bacteria/metabolism ; Biofilms ; Hydrogen-Ion Concentration ; }, abstract = {Dental plaque biofilm is a complex ecosystem. The distribution of microbial species in the biofilm is heavily influenced by local chemical interactions that result from diverse metabolic activities and the nature of the released molecules. As a relevant example, H2O2-producing bacteria can antagonize disease-associated bacteria, leading to the maintenance of a healthy oral microbiome. Herein, we report the development of a triple-sensor (redox, pH, and H2O2) scanning electrochemical microscopy (SECM) tip capable of simultaneously mapping the pH and H2O2 concentration produced by a dental plaque-derived multispecies biofilm grown on hydroxyapatite. The pH sensor of the triple SECM tip showed a near Nernstian slope of -71.1 ± 2 mV/pH (N = 3), whereas the H2O2 sensor showed a slope of -0.052 ± 0.002 nA/μM H2O2 at pH 7.2 and a detection limit of 1.0 ± 0.2 μM (N = 7). There is no significant difference in the sensitivities of H2O2 sensors at pH 6.2, 7.2, and 8.2 at 95% CI (N = 7). The pH and H2O2 sensors demonstrated excellent reversibility with response times of 3 and 5 s, respectively, along with reliable stability over 4 h at 37 °C. The sensors did not show any cross talk between pH and H2O2 concentration ([H2O2]) measurements, highlighting the accuracy and versatility of the SECM tip. Simultaneous chemical imaging of pH and [H2O2] across the biofilm revealed a clustered distribution of local H2O2 concentrations, ranging from 0 to 17 μM. Conversely, the local pH remained constant at 7.2. The relation of local chemical profiles and the distribution of bacterial species within the oral microbiome was experimentally investigated in the context of bacterial H2O2 antagonism. The benefit of clustered H2O2 production was that the total area of H2O2 produced by smaller clusters was 67% more than that of a single cluster with the same starting number of bacteria. Thus, this triple SECM tip can potentially be used to study local molecular mechanisms that result in dysbiosis of the oral microbiome.}, } @article {pmid37017538, year = {2023}, author = {Jonsdottir, I and Given, C and Penttinen, R and Jalasvuori, M}, title = {Preceding Host History of Conjugative Resistance Plasmids Affects Intra- and Interspecific Transfer Potential from Biofilm.}, journal = {mSphere}, volume = {8}, number = {3}, pages = {e0010723}, pmid = {37017538}, issn = {2379-5042}, support = {322204//Academy of Finland (AKA)/ ; 347531//Academy of Finland (AKA)/ ; }, abstract = {Conjugative plasmids can confer antimicrobial resistance (AMR) to their host bacterium. The plasmids disperse even between distantly related host species, rescuing the host from otherwise detrimental effects of antibiotics. Little is known about the role of these plasmids in the spread of AMR during antibiotic treatment. One unstudied question is whether the past evolutionary history of a plasmid in a particular species creates host specificity in its rescue potential or if interspecific coevolution can improve interspecific rescues. To study this, we coevolved the plasmid RP4 under three different host settings; solely Escherichia coli or Klebsiella pneumoniae, or alternating between both of them. The ability of evolved plasmids in bacterial biofilm to rescue susceptible planktonic host bacteria of either the same or different species during beta-lactam treatment was tested. The interspecific coevolution seemed to decrease rescue potential for the RP4 plasmid, while the K. pneumoniae evolved plasmid became more host specific. Large deletion in the region encoding the mating pair formation (Tra2) apparatus was detected in the plasmids evolved with K. pneumoniae. This adaptation resulted in the exapted evolution of resistance against a plasmid-dependent bacteriophage PRD1. Further, previous studies have suggested that mutations in this region completely abolish the plasmid's ability to conjugate; however, our study shows it is not essential for conjugation but rather affects the host-specific conjugation efficiency. Overall, the results suggest that previous evolutionary history can result in the separation of host-specific plasmid lineages that may be further amplified by unselected exaptations such as phage resistance. IMPORTANCE Antimicrobial resistance (AMR) is a major global public health threat which can rapidly spread in microbial communities via conjugative plasmids. Here, we advance with evolutionary rescue via conjugation in a more natural setting, namely, biofilm, and incorporate a broad-host range plasmid RP4 to test whether intra- and interspecific host histories affect its transfer potential. Escherichia coli and Klebsiella pneumoniae hosts were seen to elicit different evolutionary influences on the RP4 plasmid, leading to clear differences in the rescue potential and underlining the significant role of the plasmid-host interactions in the spread of AMR. We also contradicted previous reports that established certain conjugal transfer genes of RP4 as essential. This work enhances the understanding of how plasmid host range evolve in different host settings and further, the potential effects it may have on the horizontal spread of AMR in complex environments such as biofilms.}, } @article {pmid37013928, year = {2023}, author = {Dash, P and Rana, K and Turuk, J and Palo, SK and Pati, S}, title = {Antimicrobial Resistance and Biofilm Formation of Staphylococcus aureus Isolates from Febrile Cases: Findings from a Rural Cohort of Odisha, India.}, journal = {Polish journal of microbiology}, volume = {72}, number = {2}, pages = {209-214}, pmid = {37013928}, issn = {2544-4646}, mesh = {Humans ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; Drug Resistance, Bacterial ; *Staphylococcal Infections/epidemiology ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; }, abstract = {This study investigated the major pathogens in fever patients' blood in a rural cohort and characterized its virulence. A total of 718 blood samples received from IPD/OPD (inpatient department/outpatient department) patients with H/O (history of) fever were cultured, and 73 out of 83 culture-positive samples were identified as Staphylococcus aureus. The isolates showed higher resistance to penicillin, most being multidrug resistant. They formed biofilm in vitro, and 27.4% of the isolates were strong biofilm producers. They were sensitive towards linezolid, gentamicin, and tetracycline. The findings emphasize the necessity of preventing and managing staphylococcal infection and regular antimicrobial surveillance in rural areas.}, } @article {pmid37012571, year = {2023}, author = {Wang, Y and Xu, X and Zhang, S and Zhang, X and Ga, Z and Yan, Q and Lu, Y and Zuo, L and Wang, G}, title = {Vertical patterns of leaf physiology and biofilm characteristics for Hydrilla verticillata in both single and mixed communities.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {21}, pages = {59802-59812}, pmid = {37012571}, issn = {1614-7499}, support = {2022YFC3204302//National Key Research and Development Program/ ; 41971043//National Natural Science Foundation of China/ ; 2017ZX07203-003//Major Science and Technology Program for the Water Pollution Control and Treatment/ ; 2021CG0037//Cooperation and Guidance Project of Prospering Inner Mongolia through Science and Technology/ ; Y221011//Nanjing Hydraulic Research Institute/ ; }, mesh = {*Hydrocharitaceae ; Chlorophyll/pharmacology ; Plant Leaves ; Biofilms ; Water ; }, abstract = {Little is known about how community composition affects vertical patterns of leaf characteristics for submerged macrophytes in freshwater lakes. Here, after sampling Hydrilla verticillata in both single and mixed communities in shallow and deep areas in a shallow lake, we measured vertical patterns of leaf biofilm and physiology characteristics. Upper leaves of H. verticillata always had more attached abiotic biofilm matters, and all biofilm characteristics exhibited declining trends from top to bottom segments in deep areas. Moreover, the amount of attached biofilm matter in the mixed community was less than in the single community in shallow areas, but the reverse was true in deep areas. The vertical pattern of leaf physiology characteristics was obvious in the mixed community. In the shallow area, leaf pigment concentrations showed increasing trends with an increasing water depth, but the enzymatic specific activity of peroxidase (POD-ESA) was precisely the opposite. In the deep area, leaf chlorophyll concentrations were greatest in the leaves of bottom segments and lowest in top segments, while carotenoids and POD-ESA were greatest in the leaves of the middle segment-II. Light intensity and biofilm were found to play an important role in regulating the vertical patterns of photosynthetic pigments and POD-ESA. Our study highlighted the effect of community composition on the vertical pattern of leaf physiology and biofilm characteristics. HIGHLIGHTS: Biofilm characteristics always showed increasing trends with increasing water depth. Community composition changed the amount of attached biofilm matter. The vertical pattern of leaf physiology was more obvious in mixed communities. Light intensity and biofilm regulated the vertical pattern of leaf physiology.}, } @article {pmid37011602, year = {2023}, author = {Li, M and Yu, J and Guo, G and Shen, H}, title = {Interactions between macrophages and biofilm during Staphylococcus aureus-associated implant infection: difficulties and solutions.}, journal = {Journal of innate immunity}, volume = {}, number = {}, pages = {}, doi = {10.1159/000530385}, pmid = {37011602}, issn = {1662-8128}, abstract = {Staphylococcus aureus (S. aureus) biofilm is the major cause of failure of implant infection treatment that results in heavy social and economic burden on individuals, families, and communities. Planktonic S. aureus attaches to medical implant surfaces where it proliferates and is wrapped by extracellular polymeric substances (EPS), forming a solid and complex biofilm. This provides a stable environment for bacterial growth, infection maintenance, and diffusion, and protects the bacteria from antimicrobial agents and the immune system of the host. Macrophages are an important component of the innate immune system, and resist pathogen invasion and infection through phagocytosis, antigen presentation, and cytokine secretion. The persistence, spread, or clearance of infection is determined by interplay between macrophages and S. aureus in the implant infection microenvironment. In this review, we discuss the interactions between S. aureus biofilm and macrophages, including the effects of biofilm-related bacteria on the macrophage immune response, roles of myeloid-derived suppressor cells during biofilm infection, regulation of immune cell metabolic patterns by the biofilm environment, and immune evasion strategies adopted by the biofilm against macrophages. Finally, we summarize the current methods that support macrophage mediated removal of biofilms and emphasize the importance of considering multi-dimensions and factors related to implant associated infection such as immunity, metabolism, the host, and the pathogen when developing new treatments.}, } @article {pmid37010966, year = {2023}, author = {Serbanescu, MA and Apple, CG and Fernandez-Moure, JS}, title = {Role of Resident Microbial Communities in Biofilm-Related Implant Infections: Recent Insights and Implications.}, journal = {Surgical infections}, volume = {24}, number = {3}, pages = {258-264}, doi = {10.1089/sur.2023.009}, pmid = {37010966}, issn = {1557-8674}, mesh = {Humans ; *Staphylococcal Infections ; Biofilms ; Postoperative Complications ; *Microbiota ; Prostheses and Implants/adverse effects ; }, abstract = {The use of medical implants continues to grow as the population ages. Biofilm-related implant infection is the leading cause of medical implant failure and remains difficult to diagnose and treat. Recent technologies have enhanced our understanding of the composition and complex functions of microbiota occupying various body site niches. In this review, we leverage data from molecular sequencing technologies to explore how silent changes in microbial communities from various sites can influence the development of biofilm-related infections. Specifically, we address biofilm formation and recent insights of the organisms involved in biofilm-related implant infections; how composition of microbiomes from skin, nasopharyngeal, and nearby tissue can impact biofilm-formation, and infection; the role of the gut microbiome in implant-related biofilm formation; and therapeutic strategies to mitigate implant colonization.}, } @article {pmid37009860, year = {2023}, author = {Hirose, S and Asano, T and Hamada, M and Morohoshi, S and Kunihiro, T and Hanada, S}, title = {Roseomonas fluvialis sp. nov., an aerobic bacteriochlorophyll a-containing freshwater bacterium isolated from river epilithic biofilm.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {73}, number = {3}, pages = {}, doi = {10.1099/ijsem.0.005810}, pmid = {37009860}, issn = {1466-5034}, mesh = {*Fatty Acids/chemistry ; Rivers/microbiology ; Bacteriochlorophyll A ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; DNA, Bacterial/genetics ; Base Composition ; Bacterial Typing Techniques ; Sequence Analysis, DNA ; Ubiquinone ; *Methylobacteriaceae ; Biofilms ; Phospholipids ; }, abstract = {A strictly aerobic bacteriochlorophyll a-containing alphaproteobacterium, designated strain S08[T], was isolated from a biofilm sampled at Tama River in Japan. The non-motile and rod-shaped cells formed pink-beige pigmented colonies on agar plates containing organic compounds and showed in vivo absorption maxima at 798 and 866 nm in the near-infrared region, typical for the presence of bacteriochlorophyll a. The new bacterial isolate is Gram-negative, oxidase-negative and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S08[T] was closely related to species in the genus Roseomonas. The closest phylogenetic relative of strain S08[T] was Roseomonas lacus TH-G33[T] (98.2 % sequence similarity). The major cellular fatty acids were C16 : 0, C18 : 1 2-OH and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The predominant respiratory quinone was ubiquinone-9. The major polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an aminolipid. The G+C content of the genomic DNA was 70.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain S08[T] and the related Roseomonas type strains were all far lower than the cut-off value for the delineation of species. The results of polyphasic comparisons showed that strain S08[T] was clearly distinguishable from other members of the genus Roseomonas. Therefore, we propose a new species in the genus Roseomonas, namely, Roseomonas fluvialis sp. nov. The type strain is S08[T] (=DSM 111902[T]=NBRC 112025[T]).}, } @article {pmid37007057, year = {2023}, author = {Hu, Z and Tang, Y and Jiang, B and Xu, Y and Liu, S and Huang, C}, title = {Functional liposome loaded curcumin for the treatment of Streptococcus mutans biofilm.}, journal = {Frontiers in chemistry}, volume = {11}, number = {}, pages = {1160521}, pmid = {37007057}, issn = {2296-2646}, abstract = {Introduction: Plaque biofilms, mainly formed by Streptococcus mutans (S. mutans), play an important role in the occurrence and development of dental caries. Antibiotic treatment is the traditional way to control plaque. However, problems such as poor drug penetration and antibiotic resistance have encouraged the search for alternative strategies. In this paper, we hope to avoid antibiotic resistance through the antibacterial effect of curcumin, a natural plant extract with photodynamic effects, on S. mutans. However, the clinical application of curcumin is limited due to its low water solubility, poor stability, high metabolic rate, fast clearance rate, and limited bioavailability. In recent years, liposomes have become a widely used drug carrier due to their numerous advantages, such as high drug loading efficiency, high stability in the biological environment, controlled release, biocompatibility, non-toxic, and biodegradability. So, we constructed a curcumin-loaded liposome (Cur@LP) to avoid the defect of curcumin. Methods: Cur@LP functioned with NHS can adhere to the surface of the S. mutans biofilm by condensation reaction. Liposome (LP) and Cur@LP was characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The cytotoxicity of Cur@LP was evaluated by CCK-8 assay and LDH assay. The adhesion of Cur@LP to S. mutans biofilm was observed by confocal laser scanning microscope (CLSM). The antibiofilm efficiency of Cur@LP were evaluated by crystal violet staining, CLSM, and scanning electron microscope (SEM). Results: The mean diameter of LP and Cur@LP were 206.67 ± 8.38 nm and 312 ± 18.78 nm respectively. The ζ-potential of LP and Cur@LP were ∼-19.3 mV and ∼-20.8 mV respectively. The encapsulation efficiency of Cur@LP was (42.61 ± 2.19) %, and curcumin was rapidly released up to ±21% at 2 h. Cur@LP has negligible cytotoxicity, and can effectively adhered to the S. mutans biofilm and inhibited its growth. Discussion: Curcumin has been widely studied in many fields such as cancer, which can be attributed to its antioxidant and anti-inflammatory effects. At present, there are few studies on the delivery of curcumin to S. mutans biofilm. In this study, we verified the adhesion and antibiofilm of Cur@LP to S. mutans biofilm. This biofilm removal strategy has the potential to be translated into the clinic.}, } @article {pmid37005968, year = {2023}, author = {Yu, F and Dong, C and Zhang, Y and Che, R and Xie, C and Liu, Y and Zhang, Z and Li, L and Chen, X and Cai, X and Wang, G and Li, Y}, title = {GrpE and ComD contribute to the adherence, biofilm formation, and pathogenicity of Streptococcus suis.}, journal = {Archives of microbiology}, volume = {205}, number = {4}, pages = {159}, pmid = {37005968}, issn = {1432-072X}, support = {Grant No. LH2020C024//Natural Science Foundation of Heilongjiang Province, China/ ; Grant No. 31772787//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Swine ; Virulence ; *Streptococcus suis/genetics ; Biofilms ; Cytokines/metabolism ; Brain ; Disease Models, Animal ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Streptococcus suis is a major bacterial pathogen of swine and an emerging zoonotic agent that has to date resulted in substantial economic losses to the swine industry worldwide, and can cause persistent infection by forming biofilms. GrpE and histidine protein kinase ComD are important proteins implicated in the pathogenicity of S. suis, although whether they play roles in adhesion and biofilm formation has yet to be sufficiently clarified. In this study, we constructed grpE and comD deletion strains of S. suis by homologous recombination, and examined their cell adhesion and biofilm formation capacities compared with those of the wild-type strain. The pathogenicity of the grpE and comD deletion strains was evaluated using a mouse infection model, which revealed that compared with the wild-type, these deletion strains induced milder symptoms and lower bacteremia, as well as comparatively minor organ (brain, spleen, liver, and lung) lesions, in the infected mice. Moreover, the deletion of grpE and comD significantly reduced the pro-inflammatory cytokine (IL-6, IL-1β, and TNF-α) induction capacity of S. suis. Collectively, the findings of this study indicate that the GrpE and ComD proteins of Streptococcus suis play key roles in the adherence to PK-15 cells and the formation of biofilms, thereby contributing to the virulence of this pathogen.}, } @article {pmid37004897, year = {2023}, author = {Koskeroglu, K and Barel, M and Hizlisoy, H and Yildirim, Y}, title = {"Biofilm Formationand Antibiotic Resistance Profiles of Water-borne Pathogens.}, journal = {Research in microbiology}, volume = {}, number = {}, pages = {104056}, doi = {10.1016/j.resmic.2023.104056}, pmid = {37004897}, issn = {1769-7123}, abstract = {Water sources (surface water, drinking water, rivers, and ponds) are significant reservoirs for transmitting antibiotic-resistant bacteria. In addition, these waters are an important public health problem because they are suitable environments for transferring antibiotic resistance genes between bacterial species. Our study aimed to assess the prevalence of Extended-spectrum beta-lactamase (ESBL) producing isolates in water samples, the susceptibility of the isolates to the specified antibiotics, the determination of biofilm ability, antibiotic resistance genes, and the molecular typing of the isolates. For this purpose, Polymerase chain reaction (PCR) and Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analyses were used. Out of 70 isolates, 15 (21%) were ESBL producing, and sent for the MALDI-TOF analysis, where Escherichia coli, Acinetobacter calcoaceticus, Enterobacter bugandensis, Acinetobacter pittii, Pseudomonas aeruginosa, Acinetobacter junii, Pseudomonas oleovorans, and Enterobacter ludwigigii were identified. Moreover, colistin resistance genes (mcr1/2/6, mcr 4, mcr 5, mcr 3/7, and mcr 8), ESBL-encoding genes(blaSHV, blaTEM, and blaCTX-M) and carbapenemase genes (blaNDM, blaOXA-48, and blaKPC) using molecular analysis (PCR) were confirmed. The colistin resistance gene was detected at 80% (12/15) in the isolates obtained. The distribution of these isolates according to resistance genes was found as mcr 1/2/6 4 (20%), mcr3/7 3 (13%), and mcr 5 (40%). Additionally, the isolates harbored blaSHV(6.6%) and blaTEM (6.6%) genes. However, blaNDM, blaOXA-48, blaKPC, and blaCTX-M genes were not detected in any isolates. According to the Congo red agar method, seven (46.6%) isolates showed negative biofilm ability, and eight (53.3%) showed moderate biofilm ability. However, the microplate method detected weak biofilm in 53.3% of the isolates.In conclusion, this study provides evidence for the existence of multidrug-resistant bacteria that co-exist with mcr and ESBL genes in water sources. These bacteria can migrate to other environments and pose increasing threats to public health.}, } @article {pmid37004854, year = {2023}, author = {Jiao, P and Tian, Q and Wolfgang, S and Dong, X and Wu, Y}, title = {Cold-resistant performance and the promoted development of functional community with flexible metabolic patterns in a Biofilm Bio-Nutrient Removal (BBNR) system amended with supplementary carbon source for phosphorus recovery.}, journal = {Environmental research}, volume = {227}, number = {}, pages = {115807}, doi = {10.1016/j.envres.2023.115807}, pmid = {37004854}, issn = {1096-0953}, mesh = {*Phosphorus ; *Bioreactors ; Carbon/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Nutrients ; Biofilms ; Nitrogen/analysis ; Sewage ; Waste Disposal, Fluid/methods ; }, abstract = {The need for recovery of phosphorus (P) from wastewater has accelerated the retrofitting of existing bio-nutrient removal (BNR) processes into bio-nutrient removal-phosphorus recovery processes (BNR-PR). A periodical carbon source supplement is needed to facilitate the P-recovery. But the impact of this amendment on the cold resistances of the reactor and the functional microorganisms (for nitrogen and phosphorus (P) removal/recovery) are still unknown. This study presents the performances of a biofilm BNR process with a carbon source regulated the P recovery (BBNR-CPR) process operating at different temperatures. When the temperature was decreased from 25 ± 1 °C to 6 ± 1 °C, the system total nitrogen and total phosphorus removals and the corresponding kinetic coefficients decreased moderately. The indicative genes of the phosphorus-accumulating organisms (e.g., Thauera spp. and Candidatus Accumulibacter spp.) increased significantly. An increase of Nitrosomonas spp. genes aligned to polyhydroxyalkanoates (PHAs), glycine, and extracellular polymeric substance synthesis were observed, which was probably related to cold resistance. The results provide a new vision for understanding the advantages of P recovery-targeted carbon source supplementation for constructing a new type of cold-resistant BBNR-CPR processes.}, } @article {pmid37004772, year = {2023}, author = {Zhou, Z and Ma, W and Li, F and Zhong, D and Zhang, W and Liu, L and Zhang, J and Zhu, Y and Su, P}, title = {Deciphering the distribution and microbial secretors of extracellular polymeric substances associated antibiotic resistance genes in tube wall biofilm.}, journal = {The Science of the total environment}, volume = {881}, number = {}, pages = {163218}, doi = {10.1016/j.scitotenv.2023.163218}, pmid = {37004772}, issn = {1879-1026}, mesh = {*Anti-Bacterial Agents/pharmacology/analysis ; Extracellular Polymeric Substance Matrix/chemistry ; *Drinking Water/analysis ; Genes, Bacterial ; Drug Resistance, Microbial/genetics ; Biofilms ; }, abstract = {Antibiotics and disinfectants have both been proposed to exert selective pressures on the biofilm as well as affecting the emergence and spread of antibiotic resistance genes (ARGs). However, the transfer mechanism of ARGs in drinking water distribution system (DWDS) under the coupling effect of antibiotics and disinfectants has not been completely understood. In the current study, four lab-scale biological annular reactors (BARs) were constructed to evaluate the effects of sulfamethoxazole (SMX) and NaClO coupling in DWDS and reveal the related mechanisms of ARGs proliferation. TetM was abundant in both the liquid phase and the biofilm, and redundancy analysis showed that the total organic carbon (TOC) and temperature were significantly correlated with ARGs in the water phase. There was a significant correlation between the relative abundance of ARGs in the biofilm phase and extracellular polymeric substances (EPS). Additionally, the proliferation and spread of ARGs in water phase were related to microbial community structure. Partial least-squares path modeling showed that antibiotic concentration may influence ARGs by affecting MGEs. These findings help us to better understand the diffusion process of ARGs in drinking water and provide a theoretical support for technologies to control ARGs at the front of pipeline.}, } @article {pmid37004626, year = {2023}, author = {Gryson, L and Meaume, S and Feldkaemper, I and Favalli, F}, title = {Anti-biofilm Activity of Povidone-Iodine and Polyhexamethylene Biguanide: Evidence from In Vitro Tests.}, journal = {Current microbiology}, volume = {80}, number = {5}, pages = {161}, pmid = {37004626}, issn = {1432-0991}, mesh = {Povidone-Iodine/pharmacology ; *Anti-Infective Agents, Local/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Biofilms ; In Vitro Techniques ; Anti-Bacterial Agents ; }, abstract = {Biofilm in chronic wounds is associated with delayed healing and ineffective local treatment. The purpose of this study was to investigate the in vitro anti-biofilm activity of two commonly used antimicrobials, povidone-iodine (PVP-I) and polyhexamethylene biguanide (PHMB). The rate of anti-biofilm activity of PVP-I, PHMB, and phosphate-buffered saline (negative control) was assessed on monomicrobial biofilms of varying maturity and composition. Antimicrobial efficacy was determined by counting colony-forming units (CFU). Live/dead cell staining and time-lapse confocal microscopy were also performed. Both PVP-I and PHMB demonstrated robust in vitro anti-biofilm activity against all tested biofilms; however, PVP-I had a more rapid action versus PHMB against methicillin-resistant Staphylococcus aureus (MRSA) biofilms, as determined by both CFU counts and microscopy. PVP-I completely eradicated Pseudomonas aeruginosa biofilms of 3- and 5-day maturity (in ≤0.5 h) and 7-day maturity (in ≤3 h), while PHMB only partially depleted cell density, with no complete biofilm eradication even after 24 h. In conclusion, PVP-I had a similar in vitro anti-biofilm activity to PHMB against biofilms of varying microbial compositions and maturity, and in some cases demonstrated more potent and rapid activity versus PHMB. PVP-I may be particularly effective in treating MRSA biofilms. However, further high-quality clinical research on the efficacy of antimicrobials is required.}, } @article {pmid37003115, year = {2023}, author = {Wang, YC and Lv, YH and Wang, C and Jiang, GY and Han, MF and Deng, JG and Hsi, HC}, title = {Microbial community evolution and functional trade-offs of biofilm in odor treatment biofilters.}, journal = {Water research}, volume = {235}, number = {}, pages = {119917}, doi = {10.1016/j.watres.2023.119917}, pmid = {37003115}, issn = {1879-2448}, mesh = {*Extracellular Polymeric Substance Matrix ; Odorants ; Bioreactors ; Biofilms ; *Microbiota ; }, abstract = {Biofilters inoculated with activated sludge are widely used for odor control in WWTP. In this process, biofilm community evolution plays an important role in the function of reactor and is closely related to reactor performance. However, the trade-offs in biofilm community and bioreactor function during the operation are still unclear. Herein, an artificially constructed biofilter for odorous gas treatment was operated for 105 days to study the trade-offs in the biofilm community and function. Biofilm colonization was found to drive community evolution during the start-up phase (phase 1, days 0-25). Although the removal efficiency of the biofilter was unsatisfactory at this phase, the microbial genera related to quorum sensing and extracellular polymeric substance secretion led to the rapid accumulation of the biofilm (2.3 kg biomass/m[3] filter bed /day). During the stable operation phase (phase 2, days 26-80), genera related to target-pollutant degradation showed increases in relative abundance, which accompanied a high removal efficiency and a stable accumulation of biofilm (1.1 kg biomass/m[3] filter bed/day). At the clogging phase (phase 3, days 81-105), a sharp decline in the biofilm accumulation rate (0.5 kg biomass/m[3] filter bed /day) and fluctuating removal efficiency were observed. The quorum quenching-related genera and quenching genes of signal molecules increased, and competition for resources among species drove the evolution of the community in this phase. The results of this study highlight the trade-offs in biofilm community and functions during the operation of bioreactors, which could help improve bioreactor performance from a biofilm community perspective.}, } @article {pmid37001755, year = {2023}, author = {Tong, Z and Wang, YC and Jiang, GY and Hu, XR and Xue, YM and Wang, C}, title = {A method establishment and application for biofilm quorum quenching activity assay.}, journal = {Chemosphere}, volume = {328}, number = {}, pages = {138549}, doi = {10.1016/j.chemosphere.2023.138549}, pmid = {37001755}, issn = {1879-1298}, mesh = {*Quorum Sensing ; Acyl-Butyrolactones ; Bacteria ; Biofilms ; *Biosensing Techniques ; }, abstract = {The existence of quorum sensing (QS) and quorum quenching (QQ) plays important roles in biofilm formation. However, direct detection of QS ability is difficult due to the low concentrations of signal molecules inside the biofilm. Therefore, QQ activity is typically used to indicate the attribution of QS/QQ to the biofilm. Nevertheless, current detection methods of QQ activity based on biosensors present undesirable operability and accuracy. In this study, the 96-well plate assay based on a specific biosensor, Agrobacterium tumefaciens A136, and a colorimetric substance, X-gal was established. The reliable fitting results were obtained by standardizing the composition of the A136 X-gal assay solution and optimizing the operating conditions. This method improved the accuracy of QQ activity detection and reduced time and cost consumption. Finally, the 96-well plate assay was successfully applied to detect the QQ activities of biofilm samples and explore possible environmental influencing factors. In general, this study provided a new strategy for understanding the QQ effect in biofilm systems.}, } @article {pmid37001699, year = {2023}, author = {Shi, S and Cao, M and Zhang, Y and Fan, X and Liu, S and Chen, J and Zhou, J}, title = {Enhanced hydrolysis/acidogenesis and potential mechanism in thermal-alkali-biofilm synergistic pretreatment of high-solid and low-organic-content sludge.}, journal = {Bioresource technology}, volume = {378}, number = {}, pages = {128988}, doi = {10.1016/j.biortech.2023.128988}, pmid = {37001699}, issn = {1873-2976}, mesh = {*Sewage/microbiology ; Anaerobiosis ; Hydrolysis ; *Alkalies/pharmacology ; Waste Disposal, Fluid/methods ; Methane ; Bioreactors ; }, abstract = {Improving the anaerobic digestion (AD) of high-solid and low-organic-content sludge is imperative for sustainable waste activated sludge (WAS) management. Here, a thermal-alkali-biofilm pretreatment (TAB) was established to treat high-solid and low-organic-content sludge and compared with thermal and thermal-alkali methods. The results showed that TAB drastically improved WAS reduction, hydrolysis/acidogenesis efficiency, and biochemical methane potential. TAB possessed the lowest sludge particle size and the highest surface charge due to the stimulated proteolysis and WAS solubilization, supported by the protease activity test and secondary substrate identification. In addition, the biofilm assistance noticeably accelerated the elimination of autochthonous bacteria in WAS (e.g., Proteobacteria) and facilitated the enrichment of specialized fermentative microorganisms (e.g., Firmicutes) along with relevant functional genes, lying molecular foundation for the enhanced hydrolysis/acidogenesis in TAB. These findings could expand the application of biofilm in the AD of WAS and provide new insight into the pretreatment strategy of high-solid and low-organic-content sludge.}, } @article {pmid37001670, year = {2023}, author = {Fang, G and Wang, J and Li, M and Yang, Q and Huang, H}, title = {In-situ cathodic electrolysis coupled with hydraulic backwash inhibited biofilm formation on a backwashable carbon nanotube membrane.}, journal = {The Science of the total environment}, volume = {878}, number = {}, pages = {163130}, doi = {10.1016/j.scitotenv.2023.163130}, pmid = {37001670}, issn = {1879-1026}, mesh = {*Nanotubes, Carbon ; Membranes, Artificial ; Filtration/methods ; *Biofouling/prevention & control ; *Water Purification/methods ; Extracellular Polymeric Substance Matrix ; Biofilms ; }, abstract = {Electro-coupled membrane filtration (ECMF) is an innovative and green technology for water and wastewater treatment. However, the dynamics of biofouling development in the ECMF system has yet been determined. This fundamental question was systematically investigated in this study through laboratory dead-end ECMF experiments. It was found that the ECMF process with an applied voltage of 3 V and a backwash interval of 60 min was capable of completely eradicating membrane biofouling in an extended filtration time of 1450 min. In contrast, membrane biofouling was much severer with a longer backwash interval of 720 min or without backwash. The complemental permeate analysis and membrane characterization results revealed that biofouling during ECMF involved two sequential stages. During the first stage, dead bacteria and their degradation debris formed a loose deposit layer on the membrane surface. The continuous accumulation of this layer decreased the electrochemical performance of the membrane cathode. As such, bacteria in the top deposit layer proliferated and secreted extracellular polymeric substances, which led to irreversible fouling in the second stage. Therefore, timely removal of the initial deposit layer by hydraulic backwash was crucial in preventing irreversible membrane biofouling. These findings provided novel insights into the synergistic effects of cathodic electrolysis and hydraulic backwash for biofouling mitigation.}, } @article {pmid36999125, year = {2023}, author = {Mamdoh, H and Hassanein, KM and Eltoony, LF and Khalifa, WA and Hamed, E and Alshammari, TO and Abd El-Kareem, DM and El-Mokhtar, MA}, title = {Clinical and Bacteriological Analyses of Biofilm-Forming Staphylococci Isolated from Diabetic Foot Ulcers.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {1737-1750}, pmid = {36999125}, issn = {1178-6973}, abstract = {BACKGROUND: Diabetes mellitus is a chronic disease that is associated with increased morbidity and mortality. Unfortunately, foot ulcers and amputations due to diabetes are very common in developing countries. The purpose of this study was to characterize the clinical presentation of diabetic foot ulcer (DFU) infections, isolate the causative agent, and analyze the biofilm formation and distribution of biofilm-related genes among isolated Staphylococci.

MATERIAL AND METHODS: The study included 100 diabetic patients suffering from DFUs attending Assiut University Hospital. Swabs were collected and antimicrobial susceptibility testing of the isolates was performed. Biofilm formation was tested phenotypically among staphylococcal isolates and the frequency of different biofilm genes was analyzed by PCR. Clinical presentations of diabetic foot ulcers were correlated with bacterial genetic characteristics. Spa types were determined using DNA Gear-a software.

RESULTS: Microbiological analysis showed that 94/100 of the DFUs were positive for bacterial growth. The majority of infections were polymicrobial (54%, n=54/100). Staphylococci were the most commonly detected organisms, of which S. aureus represented 37.5% (n=24/64), S. haemolyticus 23.4% (n=15/64), S. epidermidis 34.3% (n=22/64) and other CNS 4.7% (n=3/64). Interestingly, co-infection with more than one species of Staphylococci was observed in 17.1% (n=11/64) of samples. A high level of antibiotic resistance was observed, where 78.1% (n=50/64) of Staphylococci spp were multidrug-resistant (MDR). Phenotypic detection showed that all isolated Staphylococci were biofilm-formers with different grades. Analysis of biofilm-forming genes among Staphylococci showed that the most predominant genes were icaD, spa, and bap. Isolates with a higher number of biofilm-related genes were associated with strong biofilm formation. Sequencing of the spa gene in S. aureus showed that our isolates represent a collection of 17 different spa types.

CONCLUSION: The majority of DFUs in our hospital are polymicrobial. Staphylococci other than S.aureus are major contributors to infected DFUs. MDR and biofilm formation are marked among isolates, which is paralleled by the presence of different categories of virulence-related genes. All severely infected wounds were associated with either strong or intermediate biofilm formers. The severity of DFU is directly related to the number of biofilm genes.}, } @article {pmid36997857, year = {2023}, author = {Grudlewska-Buda, K and Skowron, K and Bauza-Kaszewska, J and Budzyńska, A and Wiktorczyk-Kapischke, N and Wilk, M and Wujak, M and Paluszak, Z}, title = {Assessment of antibiotic resistance and biofilm formation of Enterococcus species isolated from different pig farm environments in Poland.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {89}, pmid = {36997857}, issn = {1471-2180}, mesh = {Humans ; Animals ; Swine ; Vancomycin ; Farms ; Poland/epidemiology ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Enterococcus faecalis ; *Vancomycin-Resistant Enterococci ; Vancomycin Resistance ; Gentamicins ; Biofilms ; *Enterococcus faecium ; *Gram-Positive Bacterial Infections/epidemiology/veterinary/drug therapy ; }, abstract = {BACKGROUND: Enteroccocus spp. are human opportunistic pathogens causing a variety of serious and life-threating infections in humans, including urinary tract infection, endocarditis, skin infection and bacteraemia. Farm animals and direct contact with them are important sources of Enterococcus faecalis (EFA) and Enterococcus faecium (EFM) infections among farmers, veterinarians and individuals working in breeding farms and abattoirs. The spread of antibiotic-resistant strains is one of the most serious public health concerns, as clinicians will be left without therapeutic options for the management of enterococcal infections. The aim of the study was to evaluate the occurrence and antimicrobial susceptibility of EFA and EFM strains isolated from a pig farm environment and to determine the biofilm formation ability of identified Enterococcus spp. strains.

RESULTS: A total numer of 160 enterococcal isolates were obtained from 475 samples collected in total (33.7%). Among them, 110 of genetically different strains were identified and classified into EFA (82; 74.5%) and EFM (28; 25.5%). Genetic similarity analysis revealed the presence of 7 and 1 clusters among the EFA and EFM strains, respectively. The highest percentage of EFA strains (16; 19.5%) was resistant to high concentrations of gentamicin. Among the EFM strains, the most frequent strains were resistant to ampicillin and high concentrations of gentamicin (5 each; 17.9%). Six (7.3%) EFA and 4 (14.3%) EFM strains showed vancomycin resistance (VRE - Vancomycin-Resistant Enterococcus). Linezolid resistance was found in 2 strains of each species. The multiplex PCR analysis was performed to identify the vancomycin resistant enterococci. vanB, vanA and vanD genotypes were detected in 4, 1 and 1 EFA strains, respectively. Four EFA VRE-strains in total, 2 with the vanA and 2 with the vanB genotypes, were identified. The biofilm analysis revealed that all vancomycin-resistant E. faecalis and E. faecium strains demonstrated a higher biofilm-forming capacity, as compared to the susceptible strains. The lowest cell count (5.31 log CFU / cm[2]) was reisolated from the biofilm produced by the vancomycin-sensitive strain EFM 2. The highest level of re-isolated cells was observed for VRE EFA 25 and VRE EFM 7 strains, for which the number was 7 log CFU / cm[2] and 6.75 log CFU / cm[2], respectively.

CONCLUSIONS: The irrational use of antibiotics in agriculture and veterinary practice is considered to be one of the key reasons for the rapid spread of antibiotic resistance among microorganisms. Owing to the fact that piggery environment can be a reservoir of antimicrobial resistance and transmission route of antimicrobial resistance genes from commensal zoonotic bacteria to clinical strains, it is of a great importance to public health to monitor trends in this biological phenomenon.}, } @article {pmid36997849, year = {2023}, author = {Liu, X and Ye, Y and Zhang, Z and Rensing, C and Zhou, S and Nealson, KH}, title = {Prophage Induction Causes Geobacter Electroactive Biofilm Decay.}, journal = {Environmental science & technology}, volume = {57}, number = {15}, pages = {6196-6204}, doi = {10.1021/acs.est.2c08443}, pmid = {36997849}, issn = {1520-5851}, mesh = {*Geobacter ; Virus Activation ; Electrodes ; Biofilms ; *Bioelectric Energy Sources/microbiology ; }, abstract = {Sustaining a metabolically active electroactive biofilm (EAB) is essential for the high efficiency and durable operation of microbial fuel cells (MFCs). However, EABs usually decay during long-term operation, and, until now, the causes remain unknown. Here, we report that lysogenic phages can cause EAB decay in Geobacter sulfurreducens fuel cells. A cross-streak agar assay and bioinformatic analysis revealed the presence of prophages on the G. sulfurreducens genome, and a mitomycin C induction assay revealed the lysogenic to lytic transition of those prophages, resulting in a progressive decay in both current generation and the EAB. Furthermore, the addition of phages purified from decayed EAB resulted in accelerated decay of the EAB, thereafter contributing to a faster decline in current generation; otherwise, deleting prophage-related genes rescued the decay process. Our study provides the first evidence of an interaction between phages and electroactive bacteria and suggests that attack by phages is a primary cause of EAB decay, having significant implications in bioelectrochemical systems.}, } @article {pmid36997801, year = {2023}, author = {Suchi, SA and Nam, KB and Kim, YK and Tarek, H and Yoo, JC}, title = {A novel antimicrobial peptide YS12 isolated from Bacillus velezensis CBSYS12 exerts anti-biofilm properties against drug-resistant bacteria.}, journal = {Bioprocess and biosystems engineering}, volume = {46}, number = {6}, pages = {813-828}, pmid = {36997801}, issn = {1615-7605}, support = {chosun university//jin cheol yoo/ ; 2020//jin cheol yoo/ ; }, mesh = {Anti-Bacterial Agents/chemistry ; Antimicrobial Peptides ; Antimicrobial Cationic Peptides/chemistry/pharmacology ; Escherichia coli ; Gram-Negative Bacteria ; Bacteria ; *Bacillus ; *Anti-Infective Agents/pharmacology ; Microbial Sensitivity Tests ; Biofilms ; }, abstract = {Nowadays, the abuse of antibiotics has led to the rise of multi-drug-resistant bacteria. Antimicrobial peptides (AMPs), with broad-spectrum antimicrobial activity have attracted considerable attention as possible alternatives to traditional antibiotics. In this work, we aimed to evaluate the antimicrobial and anti-biofilm activity of an antimicrobial peptide designed as YS12 derived from Bacillus velezensis CBSYS12. The strain CBSYS12 was isolated from Korean food kimchi and purified followed by ultrafiltration and sequential chromatographic methodology. Hereafter, Tricine SDS-PAGE revealed a single protein band of around 3.3 kDa that was further confirmed in situ inhibitory activity of the gel. A similar molecular weight (~ 3348.4 Da) protein also appeared in MALDI-TOF confirming the purity and homogeneity of peptide YS12. Intriguingly, YS12 revealed a strong antimicrobial activity with a minimum inhibitory concentration (MIC) value ranging from 6 to 12 μg/ml for both Gram-positive and Gram-negative bacteria, such as E. coli, P. aeruginosa, MRSA 4-5, VRE 82, and M. smegmatis. We also determined the mode of action of the peptide against pathogenic microorganisms using different fluorescent dyes. In addition, the anti-biofilm assay demonstrated that peptide YS12 was able to inhibit biofilm formation around 80% for both bacterial strains E. coli and P. aeruginosa at 80 µg/ml. Notably, YS12 exhibited a greater biofilm eradication activity than commercial antibiotics. In summary, our study proposed that peptide YS12 may be used as a promising therapeutic agent to overcome drug and biofilm-related infections.}, } @article {pmid36997145, year = {2023}, author = {Liu, Y and Wu, B and Cui, X and Ren, Q and Ren, T and Zhou, Y}, title = {Distribution and dynamics of antibiotic resistance genes in a three-dimensional multifunctional biofilm during greywater treatment.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {327}, number = {}, pages = {121533}, doi = {10.1016/j.envpol.2023.121533}, pmid = {36997145}, issn = {1873-6424}, mesh = {*Genes, Bacterial ; *Anti-Bacterial Agents/pharmacology ; Drug Resistance, Microbial/genetics ; Biofilms ; Extracellular Polymeric Substance Matrix ; }, abstract = {Antibiotic resistance genes (ARGs) have been identified as serious threats to public health. Despite the widespread in various systems, dynamics of ARGs in three-dimensional multifunctional biofilm (3D-MFB) treating greywater are largely undefined. This work tracked the distributions and dynamics of eight target genes (intI1, korB, sul1, sul2, tetM, ermB, blaCTX-M and qnrS) in a 3D-MFB during greywater treatment. Results showed that hydraulic retention times at 9.0 h achieved the highest linear alkylbenzene sulfonate (LAS) and total nitrogen removal rates at 99.4% and 79.6%, respectively. ARGs presented significant liquid-solid distribution feature, but non-significant with biofilm position. Intracellular ARGs (predominant by intI1, korB, sul1 and sul2) at bottom biofilm were 210- to 4.2 × 10[4]- fold higher than that in cell-free liquid. Extracellular polymeric substances (EPS)-attached LAS showed linear relationship with most of ARGs (R[2] > 0.90, P < 0.05). Sphingobacteriales, Chlamydiales, Microthrixaceae, SB-1, Cryomorphaceae, Chitinophagaceae, Leadbetterella and Niabella were tightly bound up with target ARGs. Key is that EPS-attached LAS considerably determines the occurrence of ARGs, and microbial taxa play an important role in the dissemination of ARGs in the 3D-MFB.}, } @article {pmid36996938, year = {2023}, author = {Asif, M and Alvi, IA and Waqas, M and Basit, A and Raza, FA and Rehman, SU}, title = {A K-17 serotype specific Klebsiella phage JKP2 with biofilm reduction potential.}, journal = {Virus research}, volume = {329}, number = {}, pages = {199107}, pmid = {36996938}, issn = {1872-7492}, mesh = {*Bacteriophages/genetics ; Klebsiella/genetics ; Serogroup ; Klebsiella pneumoniae ; *Caudovirales ; Biofilms ; }, abstract = {Klebsiella pneumoniae is an opportunistic pathogen responsible for nearly one-third of all Gram-negative infections. Increasing antibiotic resistance has pushed scientists to look for alternative therapeutics. Bacteriophages have emerged as one of the promising alternatives. In the current study, the Klebsiella phage JKP2 was isolated from a sewage sample and characterized against the K-17 serotype of K. pneumoniae. It produced bulls-eye-shaped clear plaques and has a latent period of 45 min with a burst size of 70 pfu/cell. It remained stable at tested pH (5 to 10) and temperatures (37 to 60 °C). Its optimum temperature for long-term storage is 4 °C and -80 °C. The JKP2 showed its infectivity against the K. pneumoniae K-17 serotype only. It controlled planktonic cells of K. pneumoniae 12 h post-incubation. At MOI-1, it efficiently eliminated 98% of 24 and 96% of 48-hour-old biofilm and 86% and 82% of mature biofilm of day 3 and 4, respectively. The JKP2 has an icosahedral capsid of 54 ± 0.5 nm with a short, non-contractile tail, measuring 12 ± 0.2 nm. It possesses a double-stranded DNA genome of 43.2 kbp with 54.1% GC content and encodes 54 proteins, including 29 with known functions and 25 with unknown functions. JKP2 was classified as Drulisvirus within the Autographiviridae family. It uses a T7-like direct terminal repeat strategy for genome packaging. JKP2 can be applied safely for therapeutic purposes as it does not encode an integrase or repressor genes, antibiotic resistance genes, bacterial virulence factors, and mycotoxins.}, } @article {pmid36996693, year = {2023}, author = {Wan Omar, WH and Mahyudin, NA and Azmi, NN and Mahmud Ab Rashid, NK and Ismail, R and Mohd Yusoff, MHY and Khairil Mokhtar, NF and Sharples, GJ}, title = {Effect of natural antibacterial clays against single biofilm formation by Staphylococcus aureus and Salmonella Typhimurium bacteria on a stainless-steel surface.}, journal = {International journal of food microbiology}, volume = {394}, number = {}, pages = {110184}, doi = {10.1016/j.ijfoodmicro.2023.110184}, pmid = {36996693}, issn = {1879-3460}, mesh = {*Salmonella typhimurium ; *Staphylococcus aureus ; Clay ; Stainless Steel ; Biofilms ; Bacteria ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Staphylococcus aureus and Salmonella Typhimurium have a propensity to develop biofilms on food contact surfaces, such as stainless-steel, that persist despite rigorous cleaning and sanitizing procedures. Since both bacterial species pose a significant public health risk within the food chain, improved anti-biofilm measures are needed. This study examined the potential of clays as antibacterial and anti-biofilm agents against these two pathogens on appropriate contact surfaces. Natural soil was processed to yield leachates and suspensions of both untreated and treated clays. Soil particle size, pH, cation-exchange capacity, and metal ions were characterized to assess their importance in bacterial killing. Initial antibacterial screening was performed on nine distinct types of natural Malaysian soil using a disk diffusion assay. Untreated leachate from Kuala Gula and Kuala Kangsar clays were found to inhibit S. aureus (7.75 ± 0.25 mm) and Salmonella Typhimurium (11.85 ± 1.63 mm), respectively. The treated Kuala Gula suspension (50.0 and 25.0 %) reduced S. aureus biofilms by 4.4 and 4.2 log at 24 and 6 h, respectively, while treated Kuala Kangsar suspension (12.5 %) by a 4.16 log reduction at 6 h. Although less effective, the treated Kuala Gula leachate (50.0 %) was effective in removing Salmonella Typhimurium biofilm with a decrease of >3 log in 24 h. In contrast to Kuala Kangsar clays, the treated Kuala Gula clays contained a much higher soluble metal content, especially Al (301.05 ± 0.45 ppm), Fe (691.83 ± 4.80 ppm) and Mg (88.44 ± 0.47 ppm). Elimination of S. aureus biofilms correlated with the presence of Fe, Cu, Pb, Ni, Mn and Zn irrespective of the pH of the leachate. Our findings demonstrate that a treated suspension is the most effective for eradication of S. aureus biofilms with a potential as a sanitizer-tolerant, natural antibacterial against biofilms for applications in the food industry.}, } @article {pmid36995927, year = {2023}, author = {Mayorga-Martinez, CC and Zelenka, J and Klima, K and Kubanova, M and Ruml, T and Pumera, M}, title = {Multimodal-Driven Magnetic Microrobots with Enhanced Bactericidal Activity for Biofilm Eradication and Removal from Titanium Mesh.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {35}, number = {23}, pages = {e2300191}, doi = {10.1002/adma.202300191}, pmid = {36995927}, issn = {1521-4095}, support = {CZ.02.1.01/0.0/0.0/15_003/0000444//Advanced Functional Nanorobots/ ; //EFRR/ ; }, mesh = {Humans ; *Titanium ; Physical Phenomena ; Motion ; *Biofilms ; Magnetic Fields ; }, abstract = {Modern micro/nanorobots can perform multiple tasks for biomedical and environmental applications. Particularly, magnetic microrobots can be completely controlled by a rotating magnetic field and their motion powered and controlled without the use of toxic fuels, which makes them most promising for biomedical application. Moreover, they are able to form swarms, allowing them to perform specific tasks at a larger scale than a single microrobot. In this work, they developed magnetic microrobots composed of halloysite nanotubes as backbone and iron oxide (Fe3 O4) nanoparticles as magnetic material allowing magnetic propulsion and covered these with polyethylenimine to load ampicillin and prevent the microrobots from disassembling. These microrobots exhibit multimodal motion as single robots as well as in swarms. In addition, they can transform from tumbling to spinning motion and vice-versa, and when in swarm mode they can change their motion from vortex to ribbon and back again. Finally, the vortex motion mode is used to penetrate and disrupt the extracellular matrix of Staphylococcus aureus biofilm colonized on titanium mesh used for bone restoration, which improves the effect of the antibiotic's activity. Such magnetic microrobots for biofilm removal from medical implants could reduce implant rejection and improve patients' well-being.}, } @article {pmid36995247, year = {2023}, author = {Ding, R and Ouyang, Z and Zhang, X and Dong, Y and Guo, X and Zhu, L}, title = {Biofilm-Colonized versus Virgin Black Microplastics to Accelerate the Photodegradation of Tetracycline in Aquatic Environments: Analysis of Underneath Mechanisms.}, journal = {Environmental science & technology}, volume = {57}, number = {14}, pages = {5714-5725}, doi = {10.1021/acs.est.3c00019}, pmid = {36995247}, issn = {1520-5851}, mesh = {Photolysis ; *Microplastics ; Plastics ; Reactive Oxygen Species/chemistry ; Anti-Bacterial Agents ; Tetracycline ; *Water Pollutants, Chemical/analysis ; }, abstract = {Tire wear particles (TWPs) exposed to the aquatic environment are rapidly colonized by microorganisms and provide unique substrates for biofilm formation, which potentially serve as vectors for tetracycline (TC) to influence their behaviors and potential risks. To date, the photodegradation capacity of TWPs on contaminants due to biofilm formation has not been quantified. To accomplish this, we examined the ability of virgin TWPs (V-TWPs) and biofilm-developed TWPs (Bio-TWPs) to photodegrade TC when exposed to simulated sunlight irradiation. V-TWPs and Bio-TWPs accelerated the photodegradation of TC, with rates (kobs) of 0.0232 ± 0.0014 and 0.0152 ± 0.0010 h[-1], respectively (kobs increased by 2.5-3.7 times compared to that for only TC solution). An important factor of increased TC photodegradation behavior was identified and linked to the changed reactive oxygen species (ROS) of different TWPs. The V-TWPs were exposed to light for 48 h, resulting in more ROS for attacking TC, with hydroxyl radicals ([•]OH) and superoxide anions (O2[•-]) playing a dominant role in TC photodegradation measured using scavenger/probe chemicals. This was primarily due to the greater photosensitization effects and higher electron-transfer capacity of V-TWPs in comparison to Bio-TWPs. In addition, this study first sheds light on the unique effect and intrinsic mechanism of the crucial role of Bio-TWPs in TC photodegradation, enhancing our holistic understanding of the environmental behavior of TWPs and the associated contaminants.}, } @article {pmid36994560, year = {2023}, author = {Jiang, M and Li, Y}, title = {[Advances in electrochemically active biofilm of Shewanella oneidensis MR-1].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {39}, number = {3}, pages = {881-897}, doi = {10.13345/j.cjb.220468}, pmid = {36994560}, issn = {1872-2075}, mesh = {*Bioelectric Energy Sources/microbiology ; Biofilms ; Electrodes ; Electron Transport ; *Shewanella/chemistry/metabolism ; }, abstract = {Facing the increasingly severe energy shortage and environmental pollution, electrocatalytic processes using electroactive microorganisms provide a new alternative for achieving environmental-friendly production. Because of its unique respiratory mode and electron transfer ability, Shewanella oneidensis MR-1 has been widely used in the fields of microbial fuel cell, bioelectrosynthesis of value-added chemicals, metal waste treatment and environmental remediation system. The electrochemically active biofilm of S. oneidensis MR-1 is an excellent carrier for transferring the electrons of the electroactive microorganisms. The formation of electrochemically active biofilm is a dynamic and complex process, which is affected by many factors, such as electrode materials, culture conditions, strains and their metabolism. The electrochemically active biofilm plays a very important role in enhancing bacterial environmental stress resistance, improving nutrient uptake and electron transfer efficiency. This paper reviewed the formation process, influencing factors and applications of S. oneidensis MR-1 biofilm in bio-energy, bioremediation and biosensing, with the aim to facilitate and expand its further application.}, } @article {pmid36993593, year = {2023}, author = {Hunt, BC and Brix, V and Vath, J and Guterman, BL and Taddei, SM and Learman, BS and Brauer, AL and Shen, S and Qu, J and Armbruster, CE}, title = {Metabolic interplay between Proteus mirabilis and Enterococcus faecalis facilitates polymicrobial biofilm formation and invasive disease.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36993593}, abstract = {Polymicrobial biofilms play an important role in the development and pathogenesis of CAUTI. Proteus mirabilis and Enterococcus faecalis are common CAUTI pathogens that persistently co-colonize the catheterized urinary tract and form biofilms with increased biomass and antibiotic resistance. In this study, we uncover the metabolic interplay that drives biofilm enhancement and examine the contribution to CAUTI severity. Through compositional and proteomic biofilm analyses, we determined that the increase in biofilm biomass stems from an increase in the protein fraction of the polymicrobial biofilm matrix. We further observed an enrichment in proteins associated with ornithine and arginine metabolism in polymicrobial biofilms compared to single-species biofilms. We show that L-ornithine secretion by E. faecalis promotes arginine biosynthesis in P. mirabilis, and that disruption of this metabolic interplay abrogates the biofilm enhancement we see in vitro and leads to significant decreases in infection severity and dissemination in a murine CAUTI model.}, } @article {pmid36992682, year = {2023}, author = {Hammouda, ZK and Wasfi, R and Abdeltawab, NF}, title = {Hormonal drugs: Influence on growth, biofilm formation, and adherence of selected gut microbiota.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1147585}, pmid = {36992682}, issn = {2235-2988}, mesh = {Humans ; *Gastrointestinal Microbiome/physiology ; Escherichia coli ; Caco-2 Cells ; Progesterone ; Thyroxine/pharmacology ; Bacteria ; Biofilms ; Fatty Acids, Volatile ; }, abstract = {Many studies have reported the influence of hormonal drugs on gut microbiota composition. However, the underlying mechanism of this interaction is still under study. Therefore, this study aimed to evaluate the possible in vitro changes in selected members of gut bacteria exposed to oral hormonal drugs used for years. Selected members of gut bacteria were Bifidobacterium longum, Limosilactobacillus reuteri, Bacteroides fragilis, and Escherichia coli representing the four main phyla in the gut. Selected hormonal drugs used for a long time were estradiol, progesterone, and thyroxine. The effect of intestinal concentrations of these drugs on the selected bacterial growth, biofilm formation, and adherence to Caco-2/HT-29 cell line was assessed. Short-chain fatty acids (SCFAs) have been included in host functions including the gut, immune and nervous functions; thus, the drug's effects on their production were assayed using High- Performance Liquid Chromatography. Sex steroids significantly increased the growth of all tested bacteria except B. longum, similarly, thyroxine increased the growth of tested Gram-negative bacteria however reducing that of tested Gram-positive bacteria. The effect of drugs on biofilm formation and bacterial adherence to cell lines cocultures was variable. Progesterone decreased the biofilm formation of tested Gram-positive bacteria, it nevertheless increased L. reuteri adherence to Caco-2/HT-29 cell line cell lines coculture. By contrast, progesterone increased biofilm formation by Gram-negative bacteria and increased adherence of B. fragilis to the cell lines coculture. Moreover, thyroxine and estradiol exhibited antibiofilm activity against L. reuteri, while thyroxine increased the ability of E. coli to form a biofilm. Moreover, hormones affected bacterial adherence to cell lines independently of their effect on hydrophobicity suggesting other specific binding factors might contribute to this effect. Tested drugs affected SCFAs production variably, mostly independent of their effect on bacterial growth. In conclusion, our results showed that the microbiota signature associated with some hormonal drug consumption could be the result of the direct effect of these drugs on bacterial growth, and adherence to enterocytes besides the effect of these drugs on the host tissue targets. Additionally, these drugs affect the production of SCFAs which could contribute to some of the side effects of these drugs.}, } @article {pmid36991258, year = {2023}, author = {Al-Momani, H and Al Balawi, D and Hamed, S and Albiss, BA and Almasri, M and AlGhawrie, H and Ibrahim, L and Al Balawi, H and Al Haj Mahmoud, S and Pearson, J and Ward, C}, title = {The impact of biosynthesized ZnO nanoparticles from Olea europaea (Common Olive) on Pseudomonas aeruginosa growth and biofilm formation.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {5096}, pmid = {36991258}, issn = {2045-2322}, mesh = {*Zinc Oxide/chemistry ; *Olea/metabolism ; Pseudomonas aeruginosa ; Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; *Pseudomonas Infections ; }, abstract = {There is a limitation in the range of effectual antibiotics due to the Pseudomonas aeruginosa (PA) infection due to its innate antimicrobial resistance. Researchers have therefore been concentrating their efforts to discover advanced and cost effective antibacterial agents among the ever-increasing PA bacterial resistance strains. It has been discovered that various nanoparticles can be employed as antimicrobial agents. Here, we evaluated the antibacterial properties of the Zinc Oxide nanoparticles (ZnO NPs), which was biosynthesized, being examined on six hospital strains of PA alongside a reference strain (ATCC 27853). A chemical approach was applied to biosynthesize the ZnO NPs from Olea europaea was performed, and confirmed by using X-ray diffraction and Scanning Electron Microscopes. The nanoparticles then applied their antibacterial properties to examine them against six clinically isolated PA strains alongside the reference strain. This process tested for the results of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The Growth, biofilm formation and eradication were analyzed. The influence of the differentiating degrees ZnO NPs in regard to Quorom sensing gene expression were further examined. The ZnO NPs exhibited a crystalline size and diameter (Dc) of 40-60 nm and both the MIC and MBC tests revealed positive outcomes of concentrations of 3 and 6 mg/ml for each PA strain, respectively. At sub inhibitory concentration, The ZnO NPs were found to significantly inhibit the growth and biofilm formation of all PA strains and decreases in the biomass and metabolic behavior of PA established biofilms; these decreases varied depending on the dosage. At ZnO NPs concentrations of 900 µg/ml, the expression of majority of quorum sensing genes of all strains were significantly reduced, at ZnO NPs concentrations of 300 µg/ml, few genes were significantly impacted. In conclusion, the treatment of PA and could be other antibiotic resistant bacteria can therefore be approached by using ZnO NPs as it has been uncovered that they withhold advanced antibacterial properties.}, } @article {pmid36989304, year = {2023}, author = {Lee, SH and Secchi, E and Kang, PK}, title = {Rapid formation of bioaggregates and morphology transition to biofilm streamers induced by pore-throat flows.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {14}, pages = {e2204466120}, pmid = {36989304}, issn = {1091-6490}, support = {ECCS-2025124//National Science Foundation (NSF)/ ; }, mesh = {*Pharynx ; *Biofilms ; Microfluidics ; Neck ; }, abstract = {Bioaggregates are condensed porous materials comprising microbes, organic and inorganic matters, and water. They are commonly found in natural and engineered porous media and often cause clogging. Despite their importance, the formation mechanism of bioaggregates in porous media systems is largely unknown. Through microfluidic experiments and direct numerical simulations of fluid flow, we show that the rapid bioaggregation is driven by the interplay of the viscoelastic nature of biomass and hydrodynamic conditions at pore throats. At an early stage, unique flow structures around a pore throat promote the biomass attachment at the throat. Then, the attached biomass fluidizes when the shear stress at the partially clogged pore throat reaches a critical value. After the fluidization, the biomass is displaced and accumulated in the expansion region of throats forming bioaggregates. We further find that such criticality in shear stress triggers morphological changes in bioaggregates from rounded- to streamer-like shapes. This knowledge was used to control the clogging of throats by tuning the flow conditions: When the shear stress at the throat exceeded the critical value, clogging was prevented. The bioaggregation process did not depend on the detailed pore-throat geometry, as we reproduced the same dynamics in various pore-throat geometries. This study demonstrates that pore-throat structures, which are ubiquitous in porous media systems, induce bioaggregation and can lead to abrupt disruptions in flow.}, } @article {pmid36988848, year = {2023}, author = {Maurya, KL and Swain, G and Kumar, M and Sonwani, RK and Verma, A and Singh, RS}, title = {Biodegradation of Congo Red Dye Using Lysinibacillus Species in a Moving Bed Biofilm Reactor: Continuous Study and Kinetic Evaluation.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {36988848}, issn = {1559-0291}, abstract = {The objective of this work was to develop a low-cost and efficient biocarrier for biodegradation of azo dye (i.e., Congo red (CR) dye). The potential bacterial species, i.e., Lysinibacillus fusiformis KLM1 and Lysinibacillus macrolides KLM2, were isolated from the dye-contaminated site. These bacterial species were immobilized onto the polypropylene-polyurethane foam (PP-PUF) and employed in a moving bed biofilm reactor (MBBR) for the treatment of CR dye. The effectiveness of the MBBR was investigated by operating the bioreactor in a continuous mode at various initial CR dye concentrations (50-250 mg/L) for 113 days. The removal efficiency was found in the range of 88.4-64.6% when the initial dye concentration was varied from 50 to 250 mg/L. The maximum elimination capacity (EC) of 213.18 mg/L.d was found at 250 mg/L of CR dye concentration. In addition, the CR dye utilization rate in the MBBR was studied by using two kinetics, namely, first-order and second-order (Grau) models. The high regression coefficients (R[2] > 0.97) and the satisfactory root mean square (RMSE) values (0.00096-0.02610) indicated the reasonable prediction of CR dye degradation rate by the Grau model.}, } @article {pmid36987290, year = {2023}, author = {Fan, Z and Zhou, X}, title = {Decoding the Role of Extracellular Polymeric Substances in Enhancing Nitrogen Removal from High-Ammonia and Low-C/N Wastewater in a Sequencing Batch Packed-Bed Biofilm Reactor.}, journal = {Polymers}, volume = {15}, number = {6}, pages = {}, pmid = {36987290}, issn = {2073-4360}, support = {21607111//National Natural Science Foundation of China/ ; 201803D31052//Key Research and Development Projects of Shanxi Province/ ; }, abstract = {Although the role of extracellular polymeric substances (EPSs) as a viscous high-molecular polymer in biological wastewater treatment has been recognized, in-depth knowledge of how EPSs affect nitrogen removal remains limited in biofilm-based reactors. Herein, we explored EPS characteristics associated with nitrogen removal from high-ammonia (NH4[+]-N: 300 mg/L) and low carbon-to-nitrogen ratio (C/N: 2-3) wastewater in a sequencing batch packed-bed biofilm reactor (SBPBBR) under four different operating scenarios for a total of 112 cycles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared (FTIR) analysis revealed that the distinct physicochemical properties, interface microstructure, and chemical composition of the bio-carrier were conducive to biofilm formation and microbial immobilization and enrichment. Under the optimal conditions (C/N: 3, dissolved oxygen: 1.3 mg/L, and cycle time: 12 h), 88.9% ammonia removal efficiency (ARE) and 81.9% nitrogen removal efficiency (NRE) could be achieved in the SBPBBR. Based on visual and SEM observations of the bio-carriers, biofilm development, biomass concentration, and microbial morphology were closely linked with nitrogen removal performance. Moreover, FTIR and three-dimensional excitation-emission matrix (3D-EEM) spectroscopy demonstrated that tightly bound EPSs (TB-EPSs) play a more important role in maintaining the stability of the biofilm. Significant shifts in the number, intensity, and position of fluorescence peaks of EPSs determined different nitrogen removal. More importantly, the high presence of tryptophan proteins and humic acids might promote advanced nitrogen removal. These findings uncover intrinsic correlations between EPSs and nitrogen removal for better controlling and optimizing biofilm reactors.}, } @article {pmid36987156, year = {2023}, author = {Cai, K and Liu, Y and Yue, Y and Liu, Y and Guo, F}, title = {Essential Oil Nanoemulsion Hydrogel with Anti-Biofilm Activity for the Treatment of Infected Wounds.}, journal = {Polymers}, volume = {15}, number = {6}, pages = {}, pmid = {36987156}, issn = {2073-4360}, support = {210719155864030//Technology Planning Project/ ; 2021ZDZX2051//Guangdong Provincial Science/ ; 2020LKSFG02E//Li Ka Shing Foundation Cross-Disciplinary Research/ ; }, abstract = {The formation of a bacterial biofilm on an infected wound can impede drug penetration and greatly thwart the healing process. Thus, it is essential to develop a wound dressing that can inhibit the growth of and remove biofilms, facilitating the healing of infected wounds. In this study, optimized eucalyptus essential oil nanoemulsions (EEO NEs) were prepared from eucalyptus essential oil, Tween 80, anhydrous ethanol, and water. Afterward, they were combined with a hydrogel matrix physically cross-linked with Carbomer 940 (CBM) and carboxymethyl chitosan (CMC) to prepare eucalyptus essential oil nanoemulsion hydrogels (CBM/CMC/EEO NE). The physical-chemical properties, in vitro bacterial inhibition, and biocompatibility of EEO NE and CBM/CMC/EEO NE were extensively investigated and the infected wound models were proposed to validate the in vivo therapeutic efficacy of CBM/CMC/EEO NE. The results showed that the average particle size of EEO NE was 15.34 ± 3.77 nm with PDI ˂ 0.2, the minimum inhibitory concentration (MIC) of EEO NE was 15 mg/mL, and the minimum bactericidal concentration (MBC) against S. aureus was 25 mg/mL. The inhibition and clearance of EEO NE against S. aureus biofilm at 2×MIC concentrations were 77.530 ± 7.292% and 60.700 ± 3.341%, respectively, demonstrating high anti-biofilm activity in vitro. CBM/CMC/EEO NE exhibited good rheology, water retention, porosity, water vapor permeability, and biocompatibility, meeting the requirements for trauma dressings. In vivo experiments revealed that CBM/CMC/EEO NE effectively promoted wound healing, reduced the bacterial load of wounds, and accelerated the recovery of epidermal and dermal tissue cells. Moreover, CBM/CMC/EEO NE significantly down-regulated the expression of two inflammatory factors, IL-6 and TNF-α, and up-regulated three growth-promoting factors, TGF-β1, VEGF, and EGF. Thus, the CBM/CMC/EEO NE hydrogel effectively treated wounds infected with S. aureus, enhancing the healing process. It is expected to be a new clinical alternative for healing infected wounds in the future.}, } @article {pmid36987108, year = {2023}, author = {Adeosun, IJ and Baloyi, IT and Cosa, S}, title = {Correction: Adeosun et al. Anti-Biofilm and Associated Anti-Virulence Activities of Selected Phytochemical Compounds against Klebsiella pneumoniae. Plants 2022, 11, 1429.}, journal = {Plants (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, pmid = {36987108}, issn = {2223-7747}, abstract = {In the original publication [...].}, } @article {pmid36986869, year = {2023}, author = {Velázquez-Moreno, S and González-Amaro, AM and Aragón-Piña, A and López-López, LI and Sánchez-Sánchez, R and Pérez-Díaz, MA and Oliva Rodríguez, R and Lorenzo-Leal, AC and González-Ortega, O and Martinez-Gutierrez, F and Bach, H}, title = {Use of a Cellulase from Trichoderma reesei as an Adjuvant for Enterococcus faecalis Biofilm Disruption in Combination with Antibiotics as an Alternative Treatment in Secondary Endodontic Infection.}, journal = {Pharmaceutics}, volume = {15}, number = {3}, pages = {}, pmid = {36986869}, issn = {1999-4923}, abstract = {Apical periodontitis is an inflammation leading to the injury and destruction of periradicular tissues. It is a sequence of events that starts from root canal infection, endodontic treatment, caries, or other dental interventions. Enterococcus faecalis is a ubiquitous oral pathogen that is challenging to eradicate because of biofilm formation during tooth infection. This study evaluated a hydrolase (CEL) from the fungus Trichoderma reesei combined with amoxicillin/clavulanic acid as a treatment against a clinical E. faecalis strain. Electron microscopy was used to visualize the structure modification of the extracellular polymeric substances. Biofilms were developed on human dental apices using standardized bioreactors to evaluate the antibiofilm activity of the treatment. Calcein and ethidium homodimer assays were used to evaluate the cytotoxic activity in human fibroblasts. In contrast, the human-derived monocytic cell line (THP-1) was used to evaluate the immunological response of CEL. In addition, the secretion of the pro-inflammatory cytokines IL-6 and TNF-α and the anti-inflammatory cytokine IL-10 were measured by ELISA. The results demonstrated that CEL did not induce the secretion of IL-6 and TNF-α when compared with lipopolysaccharide used as a positive control. Furthermore, the treatment combining CEL with amoxicillin/clavulanic acid showed excellent antibiofilm activity, with a 91.4% reduction in CFU on apical biofilms and a 97.6% reduction in the microcolonies. The results of this study could be used to develop a treatment to help eradicate persistent E. faecalis in apical periodontitis.}, } @article {pmid36986852, year = {2023}, author = {Fathil, MAM and Katas, H}, title = {Antibacterial, Anti-Biofilm and Pro-Migratory Effects of Double Layered Hydrogels Packaged with Lactoferrin-DsiRNA-Silver Nanoparticles for Chronic Wound Therapy.}, journal = {Pharmaceutics}, volume = {15}, number = {3}, pages = {}, pmid = {36986852}, issn = {1999-4923}, support = {PRGS/1/2020/STG05/UKM/02/3//Ministry of Higher Education/ ; }, abstract = {Antimicrobial resistance and biofilm formation in diabetic foot infections worsened during the COVID-19 pandemic, resulting in more severe infections and increased amputations. Therefore, this study aimed to develop a dressing that could effectively aid in the wound healing process and prevent bacterial infections by exerting both antibacterial and anti-biofilm effects. Silver nanoparticles (AgNPs) and lactoferrin (LTF) have been investigated as alternative antimicrobial and anti-biofilm agents, respectively, while dicer-substrate short interfering RNA (DsiRNA) has also been studied for its wound healing effect in diabetic wounds. In this study, AgNPs were complexed with LTF and DsiRNA via simple complexation before packaging in gelatin hydrogels. The formed hydrogels exhibited 1668% maximum swellability, with a 46.67 ± 10.33 µm average pore size. The hydrogels demonstrated positive antibacterial and anti-biofilm effects toward the selected Gram-positive and Gram-negative bacteria. The hydrogel containing AgLTF at 125 µg/mL was also non-cytotoxic on HaCaT cells for up to 72 h of incubation. The hydrogels containing DsiRNA and LTF demonstrated superior pro-migratory effects compared to the control group. In conclusion, the AgLTF-DsiRNA-loaded hydrogel possessed antibacterial, anti-biofilm, and pro-migratory activities. These findings provide a further understanding and knowledge on forming multipronged AgNPs consisting of DsiRNA and LTF for chronic wound therapy.}, } @article {pmid36985403, year = {2023}, author = {Liu, X and Yao, H and Zhao, X and Ge, C}, title = {Biofilm Formation and Control of Foodborne Pathogenic Bacteria.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {6}, pages = {}, pmid = {36985403}, issn = {1420-3049}, mesh = {Humans ; Food ; *Refuse Disposal ; Bacteria ; Biofilms ; *Foodborne Diseases/prevention & control/microbiology ; Food Microbiology ; }, abstract = {Biofilms are microbial aggregation membranes that are formed when microorganisms attach to the surfaces of living or nonliving things. Importantly, biofilm properties provide microorganisms with protection against environmental pressures and enhance their resistance to antimicrobial agents, contributing to microbial persistence and toxicity. Thus, bacterial biofilm formation is part of the bacterial survival mechanism. However, if foodborne pathogens form biofilms, the risk of foodborne disease infections can be greatly exacerbated, which can cause major public health risks and lead to adverse economic consequences. Therefore, research on biofilms and their removal strategies are very important in the food industry. Food waste due to spoilage within the food industry remains a global challenge to environmental sustainability and the security of food supplies. This review describes bacterial biofilm formation, elaborates on the problem associated with biofilms in the food industry, enumerates several kinds of common foodborne pathogens in biofilms, summarizes the current strategies used to eliminate or control harmful bacterial biofilm formation, introduces the current and emerging control strategies, and emphasizes future development prospects with respect to bacterial biofilms.}, } @article {pmid36985334, year = {2023}, author = {Richter, AM and Konrat, K and Osland, AM and Brook, E and Oastler, C and Vestby, LK and Gosling, RJ and Nesse, LL and Arvand, M}, title = {Evaluation of Biofilm Cultivation Models for Efficacy Testing of Disinfectants against Salmonella Typhimurium Biofilms.}, journal = {Microorganisms}, volume = {11}, number = {3}, pages = {}, pmid = {36985334}, issn = {2076-2607}, support = {773830//European Union's Horizon 2020 Research and Innovation programme/ ; CR2006//Department for Environment, Food and Rural Affairs (Defra)/ ; }, abstract = {Within the European Union, Salmonella is frequently reported in food and feed products. A major route of transmission is upon contact with contaminated surfaces. In nature, bacteria such as Salmonella are often encountered in biofilms, where they are protected against antibiotics and disinfectants. Therefore, the removal and inactivation of biofilms is essential to ensure hygienic conditions. Currently, recommendations for disinfectant usage are based on results of efficacy testing against planktonic bacteria. There are no biofilm-specific standards for the efficacy testing of disinfectants against Salmonella. Here, we assessed three models for disinfectant efficacy testing on Salmonella Typhimurium biofilms. Achievable bacterial counts per biofilm, repeatability, and intra-laboratory reproducibility were analyzed. Biofilms of two Salmonella strains were grown on different surfaces and treated with glutaraldehyde or peracetic acid. Disinfectant efficacy was compared with results for planktonic Salmonella. All methods resulted in highly repeatable cell numbers per biofilm, with one assay showing variations of less than 1 log10 CFU in all experiments for both strains tested. Disinfectant concentrations required to inactivate biofilms were higher compared to planktonic cells. Differences were found between the biofilm methods regarding maximal achievable cell numbers, repeatability, and intra-laboratory reproducibility of results, which may be used to identify the most appropriate method in relation to application context. Developing a standardized protocol for testing disinfectant efficacy on biofilms will help identify conditions that are effective against biofilms.}, } @article {pmid36985206, year = {2023}, author = {da Silva, AA and Galego, L and Arraiano, CM}, title = {New Perspectives on BolA: A Still Mysterious Protein Connecting Morphogenesis, Biofilm Production, Virulence, Iron Metabolism, and Stress Survival.}, journal = {Microorganisms}, volume = {11}, number = {3}, pages = {}, pmid = {36985206}, issn = {2076-2607}, support = {MOSTMICRO-ITQB R&D Unit (UIDB/04612/2020)//FCT-Fundação para a Ciência e a Tecnologia, I.P./ ; LS4FUTURE Associated Laboratory (LA/P/0087/2020)//FCT-Fundação para a Ciência e a Tecnologia, I.P.-/ ; Project PTDC/BIA MIC/1399/2014//FCT-Fundação para a Ciência e a Tecnologia/ ; Doctoral grant to A.A.S. number SFRH/BD/133616/2017//FCT-Fundação para a Ciência e a Tecnologia/ ; }, abstract = {The BolA-like protein family is widespread among prokaryotes and eukaryotes. BolA was originally described in E. coli as a gene induced in the stationary phase and in stress conditions. The BolA overexpression makes cells spherical. It was characterized as a transcription factor modulating cellular processes such as cell permeability, biofilm production, motility, and flagella assembly. BolA is important in the switch between motile and sedentary lifestyles having connections with the signaling molecule c-di-GMP. BolA was considered a virulence factor in pathogens such as Salmonella Typhimurium and Klebsiella pneumoniae and it promotes bacterial survival when facing stresses due to host defenses. In E. coli, the BolA homologue IbaG is associated with resistance to acidic stress, and in Vibrio cholerae, IbaG is important for animal cell colonization. Recently, it was demonstrated that BolA is phosphorylated and this modification is important for the stability/turnover of BolA and its activity as a transcription factor. The results indicate that there is a physical interaction between BolA-like proteins and the CGFS-type Grx proteins during the biogenesis of Fe-S clusters, iron trafficking and storage. We also review recent progress regarding the cellular and molecular mechanisms by which BolA/Grx protein complexes are involved in the regulation of iron homeostasis in eukaryotes and prokaryotes.}, } @article {pmid36985196, year = {2023}, author = {Marra, D and Perna, I and Pota, G and Vitiello, G and Pezzella, A and Toscano, G and Luciani, G and Caserta, S}, title = {Nanoparticle Coatings on Glass Surfaces to Prevent Pseudomonas fluorescens AR 11 Biofilm Formation.}, journal = {Microorganisms}, volume = {11}, number = {3}, pages = {}, pmid = {36985196}, issn = {2076-2607}, abstract = {Microbial colonization of surfaces is a sanitary and industrial issue for many applications, leading to product contamination and human infections. When microorganisms closely interact with a surface, they start to produce an exo-polysaccaridic matrix to adhere to and protect themselves from adverse environmental conditions. This type of structure is called a biofilm. The aim of our work is to investigate novel technologies able to prevent biofilm formation by surface coatings. We coated glass surfaces with melanin-ZnO2, melanin-TiO2, and TiO2 hybrid nanoparticles. The functionalization was performed using cold plasma to activate glass-substrate-coated surfaces, that were characterized by performing water and soybean oil wetting tests. A quantitative characterization of the antibiofilm properties was done using Pseudomonas fluorescens AR 11 as a model organism. Biofilm morphologies were observed using confocal laser scanning microscopy and image analysis techniques were used to obtain quantitative morphological parameters. The results highlight the efficacy of the proposed surface coating to prevent biofilm formation. Melanin-TiO2 proved to be the most efficient among the particles investigated. Our results can be a valuable support for future implementation of the technique proposed here in an extended range of applications that may include further testing on other strains and other support materials.}, } @article {pmid36985130, year = {2023}, author = {Rühl-Teichner, J and Jacobmeyer, L and Leidner, U and Semmler, T and Ewers, C}, title = {Genomic Diversity, Antimicrobial Susceptibility, and Biofilm Formation of Clinical Acinetobacter baumannii Isolates from Horses.}, journal = {Microorganisms}, volume = {11}, number = {3}, pages = {}, pmid = {36985130}, issn = {2076-2607}, abstract = {Acinetobacter (A.) baumannii is an opportunistic pathogen that causes severe infections in humans and animals, including horses. The occurrence of dominant international clones (ICs), frequent multidrug resistance, and the capability to form biofilms are considered major factors in the successful spread of A. baumannii in human and veterinary clinical environments. Since little is known about A. baumannii isolates from horses, we studied 78 equine A. baumannii isolates obtained from clinical samples between 2008 and 2020 for their antimicrobial resistance (AMR), clonal distribution, biofilm-associated genes (BAGs), and biofilm-forming capability. Based on whole-genome sequence analyses, ICs, multilocus (ML) and core-genome ML sequence types (STs), and AMR genes were determined. Antimicrobial susceptibility testing was performed by microbroth dilution. A crystal violet assay was used for biofilm quantification. Almost 37.2% of the isolates were assigned to IC1 (10.3%), IC2 (20.5%), and IC3 (6.4%). Overall, the isolates revealed high genomic diversity. We identified 51 different STs, including 22 novel STs (ST1723-ST1744), and 34 variants of the intrinsic oxacillinase (OXA), including 8 novel variants (OXA-970 to OXA-977). All isolates were resistant to ampicillin, amoxicillin/clavulanic acid, cephalexin, cefpodoxime, and nitrofurantoin. IC1-IC3 isolates were also resistant to gentamicin, enrofloxacin, marbofloxacin, tetracycline, and trimethoprim/sulfamethoxazole. All isolates were susceptible to imipenem. Thirty-one multidrug-resistant (MDR) isolates mainly accumulated in the IC1-IC3 groups. In general, these isolates showed less biofilm formation (IC1 = 25.0%, IC2 = 18.4%, IC3 = 15.0%) than the group of non-IC1-IC3 isolates (58.4%). Isolates belonging to the same ICs/STs revealed identical BAG patterns. BAG blp1 was absent in all isolates, whereas bfmR and pgaA were present in all isolates. At the level of the IC groups, the AMR status was negatively correlated with the isolates' ability to form a biofilm. A considerable portion of equine A. baumannii isolates revealed ICs/STs that are globally present in humans. Both an MDR phenotype and the capability to form biofilms might lead to therapeutic failures in equine medicine, particularly due to the limited availability of licensed drugs.}, } @article {pmid36985119, year = {2023}, author = {Ioannidis, A and Chatzipanagiotou, S and Vassilaki, N and Giannakopoulos, P and Hatzaki, D and Magana, M and Sachlas, A and Mpekoulis, G and Radiotis, A and Tsakanikos, M and Tzanakaki, G and Lebessi, E and Tsolia, MN}, title = {Biofilm-Forming Bacteria Implicated in Complex Otitis Media in Children in the Post-Heptavalent Pneumococcal Conjugate Vaccine (PCV7) Era.}, journal = {Microorganisms}, volume = {11}, number = {3}, pages = {}, pmid = {36985119}, issn = {2076-2607}, abstract = {Background: Chronic media with effusion (COME) and recurrent acute otitis media (RAOM) are closely related clinical entities that affect childhood. The aims of the study were to investigate the microbiological profile of otitis-prone children in the post-PCV7 era and, to examine the biofilm-forming ability in association with clinical history and outcome during a two-year post-operative follow-up. Methods: In this prospective study, pathogens from patients with COME and RAOM were isolated and studied in vitro for their biofilm-forming ability. The minimum inhibitory concentrations (MIC) of both the planktonic and the sessile forms were compared. The outcome of the therapeutic method used in each case and patient history were correlated with the pathogens and their ability to form biofilms. Results: Haemophilus influenzae was the leading pathogen (35% in COME and 40% in RAOM), and Streptococcus pneumoniae ranked second (12% in COME and 24% in RAOM). Polymicrobial infections were identified in 5% of COME and 19% of RAOM cases. Of the isolated otopathogens, 94% were positive for biofilm formation. Conclusions: This is the first Greek research studying biofilm formation in complex otitis media-prone children population in the post-PCV7 era. High rates of polymicrobial infections, along with treatment failure in biofilms, may explain the lack of antimicrobial efficacy in otitis-prone children.}, } @article {pmid36984711, year = {2023}, author = {Li, S and Duan, L and Zhao, Y and Gao, F and Hermanowicz, SW}, title = {Analysis of Microbial Communities in Membrane Biofilm Reactors Using a High-Density Microarray.}, journal = {Membranes}, volume = {13}, number = {3}, pages = {}, pmid = {36984711}, issn = {2077-0375}, support = {2022YSKY-14//the Special Fund for Basic Scientific Research Business of Central Public Research Institutes/ ; }, abstract = {Membrane biofilm reactors (MBfRs) have attracted more and more attention in the field of wastewater treatment due to their advantages of high mass transfer efficiency and low-carbon emissions. There are many factors affecting their nitrogen removal abilities, such as operation time, electron donor types, and operation modes. The operation time is directly related to the growth status of microorganisms, so it is very important to understand the effect of different operation times on microbial composition and community succession. In this study, two parallel H2-based MBfRs were operated, and differences in microbial composition, community succession, and NO3[-]-N removal efficiency were investigated on the 30th day and the 60th day of operation. The nitrogen removal efficiency of MBfRs with an operation time of 60 days was higher than that of MBfRs with an operation time of 30 days. Proteobacteria was the dominant phylum in both MBfRs; however, the composition of the microbial community was quite different. At the class level, the community composition of Proteobacteria was similar between the two MBfRs. Alphaproteobacteria was the dominant class in MBfR, and Betaproteobacteria and Gammaproteobacteria were also in high proportion. Combined with the analysis of microbial relative abundance and concentration, the similarity of microbial distribution in the MBfRs was very low on day 30 and day 60, and the phylogenetic relationships of the top 50 dominant universal bacteria and Proteobacteria were different. Although the microbial concentration decreased with the extension of the operation time, the microbial abundance and diversity of specific functional microorganisms increased further. Therefore, the operation time had a significant effect on microbial composition and community succession.}, } @article {pmid36983858, year = {2023}, author = {Alenazy, R}, title = {Antimicrobial Activities and Biofilm Inhibition Properties of Trigonella foenumgraecum Methanol Extracts against Multidrug-Resistant Staphylococcus aureus and Escherichia coli.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {3}, pages = {}, pmid = {36983858}, issn = {2075-1729}, abstract = {Multidrug-resistant bacteria are becoming the leading cause of death globally due to their resistance to many currently used antibiotics. Bacteria naturally have intrinsic resistance or acquired resistance to certain commonly used antibiotics. Therefore, searching for novel compounds has become necessary. Trigonella foenumgraecum extract was evaluated for antimicrobial and antibiofilm activities against multidrug-resistant bacteria Staphylococcus aureus and Escherichia coli. The minimum inhibitory concentration and minimum bactericidal concentration of the extract were also determined. Moreover, gas chromatography-mass spectrometry (GC-MS) analysis was used to identify the phytochemical components present in the extract. GC-MS analysis revealed that T. foenumgraecum extract contains major compounds such as Phenol, 2-methoxy-3-(2-propenyl)-, n-Hexadecanoic acid, and 9,12,15-Octadecatrienoic acid. Both bacterial strains showed resistance to some of the antibiotics tested. T. foenumgraecum showed inhibitory activity against the tested bacterial strains with a MIC of 500 µg/mL and MBC of 1000 µg/mL. The methanol extract decreased the biofilm activity of both E. coli and S. aureus below the sub-minimum inhibitory concentration. The extract showed antibacterial and antibiofilm activity against the tested bacterial pathogens.}, } @article {pmid36983523, year = {2023}, author = {Maione, A and Imparato, M and Buonanno, A and Carraturo, F and Schettino, A and Schettino, MT and Galdiero, M and de Alteriis, E and Guida, M and Galdiero, E}, title = {Anti-Biofilm Activity of Phenyllactic Acid against Clinical Isolates of Fluconazole-Resistant Candida albicans.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {3}, pages = {}, pmid = {36983523}, issn = {2309-608X}, abstract = {Commonly found colonizing the human microbiota, Candida albicans is a microorganism known for its ability to cause infections, mainly in the vulvovaginal region, and is responsible for 85% to 90% of vulvovaginal candidiasis (VVC) cases. The development of drug resistance in C. albicans isolates after long-term therapy with fluconazole is an important complication to solve and new therapeutic strategies are required to target this organism and its pathogenicity. In the present study, phenyllactic acid (PLA) an important broad-spectrum antimicrobial compound was investigated for its antifungal and antivirulence activities against clinical isolates of C. albicans. Previously characterized strains of C. albicans isolates from women with VVC and C. albicans ATCC90028 were used to evaluate the antimicrobial and time dependent killing assay activity of PLA showing a MIC 7.5 mg mL[-1] and a complete reduction of viable Candida cells detected by killing kinetics after 4 h of treatment with PLA. Additionally, PLA significantly reduced the biomass and the metabolic activity of C. albicans biofilms and impaired biofilm formation also with changes in ERG11, ALS3, and HWP1 genes expression as detected by qPCR. PLA eradicated pre-formed biofilms as showed also with confocal laser scanning microscopy (CLSM) observations. Furthermore, the compound prolonged the survival rate of Galleria mellonella infected by C. albicans isolates. These results indicate that PLA is a promising candidate as novel and safe antifungal agents for the treatment of vulvovaginal candidiasis.}, } @article {pmid36982399, year = {2023}, author = {Li, Y and Chen, X and Xu, X and Yu, C and Liu, Y and Jiang, N and Li, J and Luo, L}, title = {Deletion of pbpC Enhances Bacterial Pathogenicity on Tomato by Affecting Biofilm Formation, Exopolysaccharides Production, and Exoenzyme Activities in Clavibacter michiganensis.}, journal = {International journal of molecular sciences}, volume = {24}, number = {6}, pages = {}, pmid = {36982399}, issn = {1422-0067}, support = {No. 6222025//The Beijing Natural Science Foundation/ ; }, mesh = {*Solanum lycopersicum ; Virulence/genetics ; *Micrococcaceae ; Gram-Positive Bacteria ; Biofilms ; Plant Diseases/microbiology ; }, abstract = {Penicillin-binding proteins (PBPs) are considered essential for bacterial peptidoglycan biosynthesis and cell wall assembly. Clavibacter michiganensis is a representative Gram-positive bacterial species that causes bacterial canker in tomato. pbpC plays a significant role in maintaining cell morphological characteristics and stress responses in C. michiganensis. The current study demonstrated that the deletion of pbpC commonly enhances bacterial pathogenicity in C. michiganensis and revealed the mechanisms through which this occurs. The expression of interrelated virulence genes, including celA, xysA, xysB, and pelA, were significantly upregulated in △pbpC mutants. Compared with those in wild-type strains, exoenzyme activities, the formation of biofilm, and the production of exopolysaccharides (EPS) were significantly increased in △pbpC mutants. It is noteworthy that EPS were responsible for the enhancement in bacterial pathogenicity, with the degree of necrotic tomato stem cankers intensifying with the injection of a gradient of EPS from C. michiganensis. These findings highlight new insights into the role of pbpC affecting bacterial pathogenicity, with an emphasis on EPS, advancing the current understanding of phytopathogenic infection strategies for Gram-positive bacteria.}, } @article {pmid36982293, year = {2023}, author = {François, P and Schrenzel, J and Götz, F}, title = {Biology and Regulation of Staphylococcal Biofilm.}, journal = {International journal of molecular sciences}, volume = {24}, number = {6}, pages = {}, pmid = {36982293}, issn = {1422-0067}, mesh = {Humans ; *Staphylococcus ; Biofilms ; Staphylococcus aureus/physiology ; *Staphylococcal Infections/microbiology ; Staphylococcus epidermidis ; Anti-Bacterial Agents/therapeutic use ; Biology ; }, abstract = {Despite continuing progress in medical and surgical procedures, staphylococci remain the major Gram-positive bacterial pathogens that cause a wide spectrum of diseases, especially in patients requiring the utilization of indwelling catheters and prosthetic devices implanted temporarily or for prolonged periods of time. Within the genus, if Staphylococcus aureus and S. epidermidis are prevalent species responsible for infections, several coagulase-negative species which are normal components of our microflora also constitute opportunistic pathogens that are able to infect patients. In such a clinical context, staphylococci producing biofilms show an increased resistance to antimicrobials and host immune defenses. Although the biochemical composition of the biofilm matrix has been extensively studied, the regulation of biofilm formation and the factors contributing to its stability and release are currently still being discovered. This review presents and discusses the composition and some regulation elements of biofilm development and describes its clinical importance. Finally, we summarize the numerous and various recent studies that address attempts to destroy an already-formed biofilm within the clinical context as a potential therapeutic strategy to avoid the removal of infected implant material, a critical event for patient convenience and health care costs.}, } @article {pmid36981945, year = {2023}, author = {Lopez-Gigosos, RM and Mariscal-Lopez, E and Gutierrez-Bedmar, M and Mariscal, A}, title = {Effect of Long-Term Use of Alcohol-Containing Handwashing Gels on the Biofilm-Forming Capacity of Staphylococcus epidermidis.}, journal = {International journal of environmental research and public health}, volume = {20}, number = {6}, pages = {}, pmid = {36981945}, issn = {1660-4601}, mesh = {Humans ; Hand Disinfection ; Staphylococcus epidermidis ; *Hand Sanitizers/pharmacology ; *COVID-19 ; Biofilms ; Ethanol/pharmacology ; Culture Media/pharmacology ; *Staphylococcal Infections/microbiology ; }, abstract = {The spread of coronavirus disease 2019 (COVID-19) has promoted the use of hand sanitizers among the general population as recommended by health authorities. Alcohols, which are used in many hand sanitizers, have been shown to promotes the formation of biofilms by certain bacteria and to increase bacterial resistance to disinfection. We investigated the effect of continued use of alcohol-based gel hand sanitizer on biofilm formation by the Staphylococcus epidermidis resident strain isolated from the hands of health science students. Hand microbes were counted before and after handwashing, and the ability to produce biofilms was investigated. We found that 179 (84.8%) strains of S. epidermidis isolated from hands had the ability to form biofilm (biofilm-positive strains) in an alcohol-free culture medium. Furthermore, the presence of alcohol in the culture medium induced biofilm formation in 13 (40.6%) of the biofilm-negative strains and increased biofilm production in 111 (76.6%) strains, which were classified as low-grade biofilm-producing. Based on our findings, there is no clear evidence that the continued use of alcohol-based gels results in the selection of strains with the capacity to form biofilms. However, other disinfectant formulations that are more commonly used in clinical settings, such as alcohol-based hand-rub solutions, should be tested for their long-term effects.}, } @article {pmid36979940, year = {2023}, author = {Shahab, M and Danial, M and Khan, T and Liang, C and Duan, X and Wang, D and Gao, H and Zheng, G}, title = {In Silico Identification of Lead Compounds for Pseudomonas Aeruginosa PqsA Enzyme: Computational Study to Block Biofilm Formation.}, journal = {Biomedicines}, volume = {11}, number = {3}, pages = {}, pmid = {36979940}, issn = {2227-9059}, abstract = {Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium implicated in acute and chronic nosocomial infections and a leading cause of patient mortality. Pseudomonas aeruginosa infections are frequently associated with the development of biofilms, which give the bacteria additional drug resistance and increase their virulence. The goal of this study was to find strong compounds that block the Anthranilate-CoA ligase enzyme made by the pqsA gene. This would stop the P. aeruginosa quorum signaling system. This enzyme plays a crucial role in the pathogenicity of P. aeruginosa by producing autoinducers for cell-to-cell communication that lead to the production of biofilms. Pharmacophore-based virtual screening was carried out utilizing a library of commercially accessible enzyme inhibitors. The most promising hits obtained during virtual screening were put through molecular docking with the help of MOE. The virtual screening yielded 7/160 and 10/249 hits (ZINC and Chembridge). Finally, 2/7 ZINC hits and 2/10 ChemBridge hits were selected as potent lead compounds employing diverse scaffolds due to their high pqsA enzyme binding affinity. The results of the pharmacophore-based virtual screening were subsequently verified using a molecular dynamic simulation-based study (MDS). Using MDS and post-MDS, the stability of the complexes was evaluated. The most promising lead compounds exhibited a high binding affinity towards protein-binding pocket and interacted with the catalytic dyad. At least one of the scaffolds selected will possibly prove useful for future research. However, further scientific confirmation in the form of preclinical and clinical research is required before implementation.}, } @article {pmid36979838, year = {2023}, author = {Zanetta, P and Squarzanti, DF and di Coste, A and Amoruso, A and Pane, M and Azzimonti, B}, title = {Growth Conditions Influence Lactobacillus Cell-Free Supernatant Impact on Viability, Biofilm Formation, and Co-Aggregation of the Oral Periodontopathogens Fusobacterium nucleatum and Porphyromonas gingivalis.}, journal = {Biomedicines}, volume = {11}, number = {3}, pages = {}, pmid = {36979838}, issn = {2227-9059}, support = {FAR-2017//Università del Piemonte Orientale/ ; }, abstract = {Fusobacterium nucleatum and Porphyromonas gingivalis human periodontopathogens play a leading part in oral squamous cell carcinoma through cell proliferation, invasion, and persistent inflammation promotion and maintenance. To explore how the activity of Lactobacillus-derived cell-free supernatants (CFSs) can be influenced by growth medium components, CFSs were produced both in the standard MRS and the novel animal-derivative-free "Terreno Industriale Lattobacilli" (TIL) media, and in vitro screened for the containment of F. nucleatum and P. gingivalis both single and co-cultured and also for the interference on their co-aggregation. The viability assay demonstrated that the Limosilactobacillus reuteri LRE11 and Ligilactobacillus salivarius LS03 MRS-produced CFSs were significantly more effective against single and co-cultured pathogens. All the other CFSs significantly improved their efficacy when produced in TIL. Both MRS- and TIL-produced CFSs significantly inhibited the single and co-cultured pathogen biofilm formation. Only Levilactobacillus brevis LBR01 CFS in MRS specifically reduced F. nucleatum and P. gingivalis co-aggregation, while viable LBR01, LS03, and LRE11 in MRS significantly co-aggregated with the pathogens, but only LS03 cultivated in TIL improved this effect. This work paves the way to better consider environmental growth conditions when screening for probiotic and postbiotic efficacy as crucial to pathogen aggregation, adhesion to the host's niches, and exclusion.}, } @article {pmid36979113, year = {2023}, author = {El-Hossary, D and Mahdy, A and Elariny, EYT and Askora, A and Merwad, AMA and Saber, T and Dahshan, H and Hakami, NY and Ibrahim, RA}, title = {Antibiotic Resistance, Virulence Gene Detection, and Biofilm Formation in Aeromonas spp. Isolated from Fish and Humans in Egypt.}, journal = {Biology}, volume = {12}, number = {3}, pages = {}, pmid = {36979113}, issn = {2079-7737}, abstract = {The genus Aeromonas is widely distributed in aquatic environments and is recognized as a potential human pathogen. Some Aeromonas species are able to cause a wide spectrum of diseases, mainly gastroenteritis, skin and soft-tissue infections, bacteremia, and sepsis. The aim of the current study was to determine the prevalence of Aeromonas spp. in raw fish markets and humans in Zagazig, Egypt; identify the factors that contribute to virulence; determine the isolates' profile of antibiotic resistance; and to elucidate the ability of Aeromonas spp. to form biofilms. The examined samples included fish tissues and organs from tilapia (Oreochromis niloticus, n = 160) and mugil (Mugil cephalus, n = 105), and human skin swabs (n = 51) and fecal samples (n = 27). Based on biochemical and PCR assays, 11 isolates (3.2%) were confirmed as Aeromonas spp. and four isolates (1.2%) were confirmed as A. hydrophila. The virulence genes including haemolysin (hyl A) and aerolysin (aer) were detected using PCR in A. hydrophila in percentages of 25% and 50%, respectively. The antimicrobial resistance of Aeromonas spp. was assessed against 14 antibiotics comprising six classes. The resistance to cefixime (81.8%) and tobramycin (45.4%) was observed. The multiple antibiotic resistance (MAR) index ranged between 0.142-0.642 with 64.2% of the isolates having MAR values equal to 0.642. Biofilm formation capacity was assessed using a microtiter plate assay, and two isolates (18.1%) were classified as biofilm producers. This study establishes a baseline for monitoring and controlling the multidrug-resistant Aeromonas spp. and especially A. hydrophila in marine foods consumed in our country to protect humans and animals.}, } @article {pmid36978493, year = {2023}, author = {Akinduti, PA and George, OW and Ohore, HU and Ariyo, OE and Popoola, ST and Adeleye, AI and Akinwande, KS and Popoola, JO and Rotimi, SO and Olufemi, FO and Omonhinmin, CA and Olasehinde, GI}, title = {Evaluation of Efflux-Mediated Resistance and Biofilm formation in Virulent Pseudomonas aeruginosa Associated with Healthcare Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978493}, issn = {2079-6382}, abstract = {Pseudomonas aeruginosa is a significant pathogen identified with healthcare-associated infections. The present study evaluates the role of biofilm and efflux pump activities in influencing high-level resistance in virulent P. aeruginosa strains in clinical infection. Phenotypic resistance in biotyped Pseudomonas aeruginosa (n = 147) from diagnosed disease conditions was classified based on multiple antibiotic resistance (MAR) indices and analysed with logistic regression for risk factors. Efflux pump activity, biofilm formation, and virulence factors were analysed for optimal association in Pseudomonas infection using receiver operation characteristics (ROC). Age-specificity (OR [CI] = 0.986 [0.946-1.027]), gender (OR [CI] = 1.44 [0.211-9.827]) and infection sources (OR [CI] = 0.860 [0.438-1.688]) were risk variables for multidrug resistance (MDR)-P. aeruginosa infection (p < 0.05). Biofilm formers caused 48.2% and 18.5% otorrhea and wound infections (95% CI = 0.820-1.032; p = 0.001) respectively and more than 30% multidrug resistance (MDR) strains demonstrated high-level efflux pump activity (95% CI = 0.762-1.016; p = 0.001), protease (95% CI = 0.112-0.480; p = 0.003), lipase (95% CI = 0.143-0.523; p = 0.001), and hemolysin (95% CI = 1.109-1.780; p = 0.001). Resistance relatedness of more than 80% and 60% to cell wall biosynthesis inhibitors (ceftazidime, ceffproxil, augumentin, ampicillin) and, DNA translational and transcriptional inhibitors (gentamicin, ciprofloxacin, ofloxacin, nitrofurantoin) were observed (p < 0.05). Strong efflux correlation (r = 0.85, p = 0.034) with MDR strains, with high predictive performances in efflux pump activity (ROC-AUC 0.78), biofilm formation (ROC-AUC 0.520), and virulence hierarchical-clustering. Combine activities of the expressed efflux pump and biofilm formation in MDR-P. aeruginosa pose risk to clinical management and infection control.}, } @article {pmid36978490, year = {2023}, author = {Rajapaksha, DC and Edirisinghe, SL and Nikapitiya, C and Whang, I and De Zoysa, M}, title = {The Antimicrobial Peptide Octopromycin Suppresses Biofilm Formation and Quorum Sensing in Acinetobacter baumannii.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978490}, issn = {2079-6382}, support = {MABIK2023M00400//National Marine Biodiversity Institute of Korea/ ; 2018R1A2B6007841//National Research Foundation of Korea/ ; 2019R1A2C1087028//National Research Foundation of Korea/ ; }, abstract = {Acinetobacter baumannii is an opportunistic bacterial pathogen that causes severe infections in immunocompromised individuals. A. baumannii forms biofilm and produces extracellular matrix, which supports bacteria to survive under harsh conditions and be resistant to antibacterial treatments. In the present study, we investigated the biofilm and quorum-sensing inhibitory effects of antimicrobial peptide, octopromycin in A. baumannii. Field emission-scanning electron microscopy results clearly showed significantly reduced biofilm mass and caused a collapse in biofilm architecture at the minimum inhibitory concentration (50 µg/mL) and minimum bactericidal concentration (200 µg/mL) of octopromycin. Antibiotic-resistant persister cells of A. baumannii were successfully killed by octopromycin treatment, and it inhibited violacein production in Chromobacterium violaceum in a concentration-dependent manner. Octopromycin also inhibited alginate production, surface movements (swarming and swimming), and twitching motility of A. baumannnii, confirming its anti-quorum-sensing activity. Multiple metabolic pathways, two-component regulation systems, quorum-sensing, and antibiotic synthesis-related pathways in A. baumannii biofilms were strongly affected by octopromycin treatment. The collective findings indicate that the antibacterial peptide octopromycin may control A. baumannii biofilms through multi-target interactions. Octopromycin could be a desirable therapeutic option for the prevention and control of A. baumannii infections.}, } @article {pmid36978452, year = {2023}, author = {Kuppusamy, R and Yasir, M and Yu, TT and Voli, F and Vittorio, O and Miller, MJ and Lewis, P and Black, DS and Willcox, M and Kumar, N}, title = {Tuning the Anthranilamide Peptidomimetic Design to Selectively Target Planktonic Bacteria and Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978452}, issn = {2079-6382}, abstract = {There is a pressing need to develop new antimicrobials to help combat the increase in antibiotic resistance that is occurring worldwide. In the current research, short amphiphilic antibacterial and antibiofilm agents were produced by tuning the hydrophobic and cationic groups of anthranilamide peptidomimetics. The attachment of a lysine cationic group at the tail position increased activity against E. coli by >16-fold (from >125 μM to 15.6 μM) and greatly reduced cytotoxicity against mammalian cells (from ≤20 μM to ≥150 μM). These compounds showed significant disruption of preformed biofilms of S. aureus at micromolar concentrations.}, } @article {pmid36978412, year = {2023}, author = {Praseetha, S and Sukumaran, ST and Dan, M and Augustus, AR and Pandian, SK and Sugathan, S}, title = {The Anti-Biofilm Potential of Linalool, a Major Compound from Hedychium larsenii, against Streptococcus pyogenes and Its Toxicity Assessment in Danio rerio.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978412}, issn = {2079-6382}, support = {P005B//Kerala State Council for Science, Technology and Environment/ ; }, abstract = {The anti-biofilm and anti-virulence potential of the essential oil (E.O.) extracted from Hedychium larsenii M. Dan & Sathish was determined against Streptococcus pyogenes. A crystal violet assay was employed to quantify the biofilm. Linalool, a monoterpene alcohol from the E.O., showed concentration-dependent biofilm inhibition, with a maximum of 91% at a concentration of 0.004% (v/v). The AlamarBlue[TM] assay also confirmed Linalool's non-bactericidal anti-biofilm efficacy (0.004%). Linalool treatment impeded micro-colony formation, mature biofilm architecture, surface coverage, and biofilm thickness and impaired cell surface hydrophobicity and EPS production. Cysteine protease synthesis was quantified using the Azocasein assay, and Linalool treatment augmented its production. This suggests that Linalool destabilizes the biofilm matrix. It altered the expression of core regulons covRS, mga, srv, and ropB, and genes associated with virulence and biofilm formation, such as speB, dltA, slo, hasA, and ciaH, as revealed by qPCR analysis. Cytotoxicity analysis using human kidney cells (HEK) and the histopathological analysis in Danio rerio proved Linalool to be a druggable molecule against the biofilms formed by S. pyogenes. This is the first report on Linalool's anti-biofilm and anti-virulence potential against S. pyogenes.}, } @article {pmid36978402, year = {2023}, author = {Regulski, M and Myntti, MF and James, GA}, title = {Anti-Biofilm Efficacy of Commonly Used Wound Care Products in In Vitro Settings.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978402}, issn = {2079-6382}, support = {Service Agreement//Next Science, LLC/ ; }, abstract = {Considering the prevalence and pathogenicity of biofilms in wounds, this study was designed to evaluate the anti-biofilm capabilities of eight commercially available wound care products using established in vitro assays for biofilms. The products evaluated included dressings with multiple delivery formats for ionic silver including nanocrystalline, gelling fibers, polyurethane (PU) foam, and polymer matrix. Additionally, non-silver-based products including an extracellular polymeric substance (EPS)-dissolving antimicrobial wound gel (BDWG), a collagenase-based debriding ointment and a fish skin-based skin substitute were also evaluated. The products were evaluated on Staphylococcus aureus and Pseudomonas aeruginosa mixed-species biofilms grown using colony drip flow reactor (CDFR) and standard drip flow reactor (DFR) methodologies. Anti-biofilm efficacy was measured by viable plate counts and confocal scanning laser microscopy (CSLM). Four of the eight wound care products tested were efficacious in inhibiting growth of new biofilm when compared with untreated controls. These four products were further evaluated against mature biofilms. BDWG was the only product that achieved greater than 2-log growth reduction (5.88 and 6.58 for S. aureus and P. aeruginosa, respectively) of a mature biofilm. Evaluating both biofilm prevention and mature biofilm disruption capacity is important to a comprehensive understanding of the anti-biofilm efficacy of wound care products.}, } @article {pmid36978347, year = {2023}, author = {Bomfim de Barros, D and de Oliveira E Lima, L and Alves da Silva, L and Cavalcante Fonseca, M and Ferreira, RC and Diniz Neto, H and da Nóbrega Alves, D and da Silva Rocha, WP and Scotti, L and de Oliveira Lima, E and Vieira Sobral, M and Cançado Castellano, LR and Moura-Mendes, J and Queiroga Sarmento Guerra, F and da Silva, MV}, title = {α-Pinene: Docking Study, Cytotoxicity, Mechanism of Action, and Anti-Biofilm Effect against Candida albicans.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {36978347}, issn = {2079-6382}, support = {student grant//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Candida albicans is associated with serious infections in immunocompromised patients. Terpenes are natural-product derivatives, widely studied as antifungal alternatives. In a previous study reported by our group, the antifungal activity of α-pinene against C. albicans was verified; α-pinene presented an MIC between 128-512 µg/mL. In this study, we evaluate time-kill, a mechanism of action using in silico and in vitro tests, anti-biofilm activity against the Candida albicans, and toxicity against human cells (HaCaT). Results from the molecular-docking simulation demonstrated that thymidylate synthase (-52 kcal mol[-1]), and δ-14-sterol reductase (-44 kcal mol[-1]) presented the best interactions. Our in vitro results suggest that α-pinene's antifungal activity involves binding to ergosterol in the cellular membrane. In the time-kill assay, the antifungal activity was not time-dependent, and also inhibited biofilm formation, while rupturing up to 88% of existing biofilm. It was non-cytotoxic to human keratinocytes. Our study supports α-pinene as a candidate to treat fungal infections caused by C. albicans.}, } @article {pmid36978196, year = {2023}, author = {Li, F and Huang, K and Wang, J and Yuan, K and Yang, Y and Liu, Y and Zhou, X and Kong, K and Yang, T and He, J and Liu, C and Ao, H and Liu, F and Liu, Q and Tang, T and Yang, S}, title = {A dual functional Ti-Ga alloy: inhibiting biofilm formation and osteoclastogenesis differentiation via disturbing iron metabolism.}, journal = {Biomaterials research}, volume = {27}, number = {1}, pages = {24}, pmid = {36978196}, issn = {1226-4601}, support = {82072235//National Natural Science Foundation of China/ ; 82272509//National Natural Science Foundation of China/ ; 92068205//National Natural Science Foundation of China/ ; 32101092//National Natural Science Foundation of China/ ; JYZZ200//Fundamental research program funding of Ninth People's Hospital affiliated to Shanghai Jiao Tong university School of Medicine/ ; 20QC1400800//Shanghai Science and Technology Development Fund/ ; JYJC202212//Cross-disciplinary Research Fund of Shanghai Ninth People's, Shanghai JiaoTong university School of Medicine/ ; 20212ACB214002//Natural Science Foundation of Jiangxi Province/ ; 22015820100//Science and Technology Innovation Action Plan of Shanghai Science and Technology Committee/ ; 2022BFH02010//Ningxia Hui Autonomous Region's Key R&D Program for Foreign Scientific and Technological Cooperation Projects/ ; 20YF1422600//Shanghai Sailing Program/ ; }, abstract = {BACKGROUND: Although biomedical implants have been widely used in orthopedic treatments, two major clinical challenges remain to be solved, one is the bacterial infection resulting in biofilm formation, and the other is aseptic loosening during implantation due to over-activated osteoclastogenesis. These factors can cause many clinical issues and even lead to implant failure. Thus, it is necessary to endow implants with antibiofilm and aseptic loosening-prevention properties, to facilitate the integration between implants and bone tissues for successful implantation. To achieve this goal, this study aimed to develop a biocompatible titanium alloy with antibiofilm and anti-aseptic loosening dual function by utilizing gallium (Ga) as a component.

METHODS: A series of Ti-Ga alloys were prepared. We examined the Ga content, Ga distribution, hardness, tensile strength, biocompatibility, and anti-biofilm performance in vitro and in vivo. We also explored how Ga[3+] ions inhibited the biofilm formation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and osteoclast differentiation.

RESULTS: The alloy exhibited outstanding antibiofilm properties against both S. aureus and E. coli in vitro and decent antibiofilm performance against S. aureus in vivo. The proteomics results demonstrated that Ga[3+] ions could disturb the bacterial Fe metabolism of both S. aureus and E. coli, inhibiting bacterial biofilm formation. In addition, Ti-Ga alloys could inhibit receptor activator of nuclear factor-κB ligand (RANKL)-dependent osteoclast differentiation and function by targeting iron metabolism, then suppressing the activation of the NF-κB signaling pathway, thus, showing their potential to prevent aseptic loosening.

CONCLUSION: This study provides an advanced Ti-Ga alloy that can be used as a promising orthopedic implant raw material for various clinical scenarios. This work also revealed that iron metabolism is the common target of Ga[3+] ions to inhibit biofilm formation and osteoclast differentiation.}, } @article {pmid36976452, year = {2023}, author = {Ebrahimi, MT and Hedayati, MA and Pirlar, RF and Mortazavi, N and Nazari, M and Ahmadi, A and Hemmati, J and Erfani, Y}, title = {Investigation of the biofilm formation in extra-intestinal pathogenic Escherichia coli ST131 strains and its correlation with the presence of fimH, afa, and kpsMSTII genes.}, journal = {Journal of applied genetics}, volume = {64}, number = {2}, pages = {367-373}, pmid = {36976452}, issn = {2190-3883}, mesh = {Humans ; *Escherichia coli/genetics ; *Escherichia coli Infections ; Virulence Factors/genetics ; Biofilms ; Anti-Bacterial Agents ; Adhesins, Escherichia coli/genetics ; Fimbriae Proteins/genetics/therapeutic use ; }, abstract = {Escherichia coli sequence type 131 (ST131) is a multidrug-resistant strain with the global dissemination. Biofilm formation-related factors include the most important virulence factors in extra-intestinal pathogenic E. coli (ExPEC) ST131 strains causing infections with treatment-limited subjects. This study aims to investigate the biofilm formation ability and its correlation with the presence of fimH, afa, and kpsMSTII genes in clinical isolates of ExPEC ST131. In this regard, the prevalence and characteristics of these strains collected and evaluated. The results revealed strong, moderate, and weak attachment abilities related to biofilm formation attributes in 45%, 20%, and 35% of strains, respectively. In the meantime, the frequency of the fimH, afa, and kpsMSTII genes among the isolates was observed as follows: fimH positive: 65%; afa positive: 55%; and kpsMSTII positive: 85%. The results convey a significant different of biofilm formation ability between clinical E. coli ST131 and non-ST131 isolates. Furthermore, while 45% of ST131 isolates produced strong biofilms, only 2% of non-ST131 isolates showed the ability to form strong biofilms. The attending of fimH, afa, and kpsMSTII genes in the majority of ST131 strains demonstrated a key role leading to biofilm formation. These findings suggested the application of fimH, afa, and kpsMSTII gene suppressors for treating biofilm infections caused by drug-resistant ST131 strains.}, } @article {pmid36972823, year = {2023}, author = {Wang, M and Muhammad, T and Gao, H and Liu, J and Liang, H}, title = {Targeted pH-responsive chitosan nanogels with Tanshinone IIA for enhancing the antibacterial/anti-biofilm efficacy.}, journal = {International journal of biological macromolecules}, volume = {237}, number = {}, pages = {124177}, doi = {10.1016/j.ijbiomac.2023.124177}, pmid = {36972823}, issn = {1879-0003}, mesh = {Humans ; *Chitosan/chemistry ; Nanogels ; Anti-Bacterial Agents/pharmacology ; Hydrogen-Ion Concentration ; Biofilms ; }, abstract = {Persistent bacterial infection caused by biofilms is one of the most serious problems that threatened human health. The development of antibacterial agents remains a challenge to penetrate biofilm and effectively treat the underlying bacterial infection. In the current study, chitosan-based nanogels were developed for encapsulating the Tanshinone IIA (TA) to enhance the antibacterial and anti-biofilm efficacy against Streptococcus mutans (S. mutans). The as-prepared nanogels (TA@CS) displayed excellent encapsulation efficiency (91.41 ± 0.11 %), uniform particle sizes (393.97 ± 13.92 nm), and enhanced positive potential (42.27 ± 1.25 mV). After being coated with CS, the stability of TA under light and other harsh environments was greatly improved. In addition, TA@CS displayed pH responsiveness, allowing it to selectively release more TA in acidic conditions. Furthermore, the positively charged TA@CS were equipped to target negatively charged biofilm surfaces and efficiently penetrate through biofilm barriers, making it promising for remarkable anti-biofilm activity. More importantly, when TA was encapsulated into CS nanogels, the antibacterial activity of TA was enhanced at least 4-fold. Meanwhile, TA@CS inhibited 72 % of biofilm formation at 500 μg/mL. The results demonstrated that the nanogels constituted CS and TA had antibacterial/anti-biofilm properties with synergistic enhanced effects, which will benefit pharmaceutical, food, and other fields.}, } @article {pmid36972812, year = {2023}, author = {Tian, H and Li, Y and Chen, H and Zhang, J and Hui, M and Xu, X and Su, Q and Smets, BF}, title = {Aerobic biodegradation of quinoline under denitrifying conditions in membrane-aerated biofilm reactor.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {326}, number = {}, pages = {121507}, doi = {10.1016/j.envpol.2023.121507}, pmid = {36972812}, issn = {1873-6424}, mesh = {*Wastewater ; Pseudomonas ; Bacteria, Aerobic ; Biofilms ; Bioreactors/microbiology ; *Quinolones ; Nitrogen ; Denitrification ; }, abstract = {Aerobic denitrification is being investigated as a novel biological nitrogen removal process, yet the knowledge on aerobic denitrification is limited to pure culture isolations and its occurrence in bioreactors remains unclear. This study investigated the feasibility and capacity of applying aerobic denitrification in membrane aerated biofilm reactor (MABR) for biological treatment of quinoline-laden wastewater. Stable and efficient removals of quinoline (91.5 ± 5.2%) and nitrate (NO3[-]) (86.5 ± 9.3%) were obtained under different operational conditions. Enhanced formation and function of extracellular polymeric substances (EPS) were observed at increasing quinoline loadings. MABR biofilm was highly enriched with aerobic quinoline-degrading bacteria, with a predominance of Rhodococcus (26.9 ± 3.7%) and secondary abundance of Pseudomonas (1.7 ± 1.2%) and Comamonas (0.94 ± 0.9%). Metagenomic analysis indicated that Rhodococcus contributed significantly to both aromatic degradation (24.5 ± 21.3%) and NO3[-] reduction (4.5 ± 3.9%), indicating its key role in aerobic denitrifying quinoline biodegradation. At increasing quinoline loadings, abundances of aerobic quinoline degradation gene oxoO and denitrifying genes of napA, nirS and nirK increased; there was a significant positive correlation of oxoO with nirS and nirK (p < 0.05). Aerobic quinoline degradation was likely initiated by hydroxylation, encoded by oxoO, followed by stepwise oxidations through 5,6-dihydroxy-1H-2-oxoquinoline or 8-hydroxycoumarin pathway. The results advance our understanding of quinoline degradation during biological nitrogen removal, and highlight the potential implementation of aerobic denitrification driven quinoline biodegradation in MABR for simultaneous removal of nitrogen and recalcitrant organic carbon from coking, coal gasification and pharmaceutical wastewaters.}, } @article {pmid36972615, year = {2023}, author = {Martinez, JPO and Vazquez, L and Takeyama, MM and Dos Santos Filho, TJ and Cavalcante, FS and Guimarães, LC and Pereira, EM and Dos Santos, KRN}, title = {Novel biochemical aspects of lugdulysin, a Staphylococcus lugdunensis metalloprotease that inhibits formation and disrupts protein biofilm of methicillin-resistant Staphylococcus aureus.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {87}, number = {6}, pages = {653-662}, doi = {10.1093/bbb/zbad035}, pmid = {36972615}, issn = {1347-6947}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; E-26/203.296/2017//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; 307594/2021-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Humans ; *Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; *Staphylococcus lugdunensis ; Biofilms ; *Staphylococcal Infections ; Metalloproteases/pharmacology ; Peptide Hydrolases ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus lugdunensis produces lugdulysin, a metalloprotease that may contribute to its virulence. This study aimed to evaluate the biochemical aspects of lugdulysin and investigate its effect on Staphylococcus aureus biofilms. The protease was isolated and characterized for its optimal pH and temperature, hydrolysis kinetics, and influence of metal cofactor supplementation. The protein structure was determined via homology modeling. The effect on S. aureus biofilms was assessed by the micromethod technique. The protease optimal pH and temperature were 7.0 and 37 °C, respectively. EDTA inhibited protease activity, confirming it as a metalloprotease. Lugdulysin activity was not recovered by divalent ion supplementation post-inhibition, and supplementation with divalent ions did not change enzymatic activity. The isolated enzyme was stable for up to 3 h. Lugdulysin significantly inhibited the formation and disrupted preestablished protein-matrix MRSA biofilm. This preliminary study indicates that lugdulysin has a potential role as a competition mechanism and/or modulation of staphylococcal biofilm.}, } @article {pmid36971546, year = {2023}, author = {Yahya, AH and Harston, SR and Colton, WL and Cabeen, MT}, title = {Distinct Screening Approaches Uncover PA14_36820 and RecA as Negative Regulators of Biofilm Phenotypes in Pseudomonas aeruginosa PA14.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0377422}, pmid = {36971546}, issn = {2165-0497}, abstract = {Pseudomonas aeruginosa commonly infects hospitalized patients and the lungs of individuals with cystic fibrosis. This species is known for forming biofilms, which are communities of bacterial cells held together and encapsulated by a self-produced extracellular matrix. The matrix provides extra protection to the constituent cells, making P. aeruginosa infections challenging to treat. We previously identified a gene, PA14_16550, which encodes a DNA-binding TetR-type repressor and whose deletion reduced biofilm formation. Here, we assessed the transcriptional impact of the 16550 deletion and found six differentially regulated genes. Among them, our results implicated PA14_36820 as a negative regulator of biofilm matrix production, while the remaining 5 had modest effects on swarming motility. We also screened a transposon library in a biofilm-impaired ΔamrZ Δ16550 strain for restoration of matrix production. Surprisingly, we found that disruption or deletion of recA increased biofilm matrix production, both in biofilm-impaired and wild-type strains. Because RecA functions both in recombination and in the DNA damage response, we asked which function of RecA is important with respect to biofilm formation by using point mutations in recA and lexA to specifically disable each function. Our results implied that loss of either function of RecA impacts biofilm formation, suggesting that enhanced biofilm formation may be one physiological response of P. aeruginosa cells to loss of either RecA function. IMPORTANCE Pseudomonas aeruginosa is a notorious human pathogen well known for forming biofilms, communities of bacteria that protect themselves within a self-secreted matrix. Here, we sought to find genetic determinants that impacted biofilm matrix production in P. aeruginosa strains. We identified a largely uncharacterized protein (PA14_36820) and, surprisingly, RecA, a widely conserved bacterial DNA recombination and repair protein, as negatively regulating biofilm matrix production. Because RecA has two main functions, we used specific mutations to isolate each function and found that both functions influenced matrix production. Identifying negative regulators of biofilm production may suggest future strategies to reduce the formation of treatment-resistant biofilms.}, } @article {pmid36971485, year = {2023}, author = {Ousey, K and Ovens, L}, title = {Comparing methods of debridement for removing biofilm in hard-to-heal wounds.}, journal = {Journal of wound care}, volume = {32}, number = {Sup3b}, pages = {S4-S10}, doi = {10.12968/jowc.2023.32.Sup3b.S4}, pmid = {36971485}, issn = {0969-0700}, mesh = {Humans ; Debridement/methods ; *Wound Healing ; *Wound Infection/therapy ; Biofilms ; }, } @article {pmid36970701, year = {2023}, author = {Aljohani, AM and El-Chami, C and Alhubail, M and Ledder, RG and O'Neill, CA and McBain, AJ}, title = {Escherichia coli Nissle 1917 inhibits biofilm formation and mitigates virulence in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1108273}, pmid = {36970701}, issn = {1664-302X}, abstract = {In the quest for mitigators of bacterial virulence, cell-free supernatants (CFS) from 25 human commensal and associated bacteria were tested for activity against Pseudomonas aeruginosa. Among these, Escherichia coli Nissle 1917 CFS significantly inhibited biofilm formation and dispersed extant pseudomonas biofilms without inhibiting planktonic bacterial growth. eDNA was reduced in biofilms following exposure to E. coli Nissle CFS, as visualized by confocal microscopy. E. coli Nissle CFS also showed a significant protective effect in a Galleria mellonella-based larval virulence assay when administrated 24 h before challenge with the P. aeruginosa. No inhibitory effects against P. aeruginosa were observed for other tested E. coli strains. According to proteomic analysis, E. coli Nissle CFS downregulated the expression of several P. aeruginosa proteins involved in motility (Flagellar secretion chaperone FliSB, B-type flagellin fliC, Type IV pilus assembly ATPase PilB), and quorum sensing (acyl-homoserine lactone synthase lasI and HTH-type quorum-sensing regulator rhlR), which are associated with biofilm formation. Physicochemical characterization of the putative antibiofilm compound(s) indicates the involvement of heat-labile proteinaceous factors of greater than 30 kDa molecular size.}, } @article {pmid36969800, year = {2023}, author = {Delaney, C and Short, B and Rajendran, R and Kean, R and Burgess, K and Williams, C and Munro, CA and Ramage, G}, title = {An integrated transcriptomic and metabolomic approach to investigate the heterogeneous Candida albicans biofilm phenotype.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100112}, pmid = {36969800}, issn = {2590-2075}, abstract = {Candida albicans is the most prevalent and notorious of the Candida species involved in bloodstream infections, which is characterised by its capacity to form robust biofilms. Biofilm formation is an important clinical entity shown to be highly variable among clinical isolates. There are various environmental and physiological factors, including nutrient availability which influence the phenotype of Candida species. However, mechanisms underpinning adaptive biofilm heterogeneity have not yet been fully explored. Within this study we have profiled previously characterised and phenotypically distinct C. albicans bloodstream isolates. We assessed the dynamic susceptibility of these differing populations to antifungal treatments using population analysis profiling in addition to assessing biofilm formation and morphological changes. High throughput methodologies of RNA-Seq and LC-MS were employed to map and integrate the transcriptional and metabolic reprogramming undertaken by heterogenous C. albicans isolates in response to biofilm and hyphal inducing serum. We found a significant relationship between biofilm heterogeneity and azole resistance (P < 0.05). In addition, we observed that in response to serum our low biofilm forming (LBF) C. albicans exhibited a significant increase in biofilm formation and hyphal elongation. The transcriptional reprogramming of LBF strains compared to high biofilm forming (HBF) was distinct, indicating a high level of plasticity and variation in stress responses by heterogenous strains. The metabolic responses, although variable between LBF and HBF, shared many of the same responses to serum. Notably, a high upregulation of the arachidonic acid cascade, part of the COX pathway, was observed and this pathway was found to induce biofilm formation in LBF 3-fold. C. albicans is a highly heterogenous bloodstream pathogen with clinical isolates varying in antifungal tolerance and biofilm formation. In addition to this, C. albicans is capable of highly complex and variable regulation of transcription and metabolic pathways and heterogeneity across isolates further increases the complexity of these pathways. Here we have shown with a dual and integrated approach, the importance of studying a diverse panel of C. albicans isolates, which has the potential to reveal distinct pathways that can harnessed for drug discovery.}, } @article {pmid36969455, year = {2023}, author = {Kang, MG and Khan, F and Tabassum, N and Cho, KJ and Jo, DM and Kim, YM}, title = {Inhibition of Biofilm and Virulence Properties of Pathogenic Bacteria by Silver and Gold Nanoparticles Synthesized from Lactiplantibacillus sp. Strain C1.}, journal = {ACS omega}, volume = {8}, number = {11}, pages = {9873-9888}, pmid = {36969455}, issn = {2470-1343}, abstract = {The emergence of antibiotic resistance in microbial pathogens necessitates the development of alternative ways to combat the infections that arise. The current study used nanotechnology as an alternate technique to control virulence characteristics and biofilm development in Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, based on the acceptance and biocompatibility of the probiotic bacteria, we chose a lactic acid bacteria (LAB) for synthesizing two types of metallic nanoparticles (NPs) in this study. Using molecular techniques, the LAB strain C1 was isolated from Kimchi food samples and identified as Lactiplantibacillus sp. strain C1. The prepared supernatant from strain C1 was used to produce gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs). C1-AuNPs and C1-AgNPs were characterized physiochemically using a variety of instruments. C1-AuNPs and C1-AgNPs had spherical shapes and sizes of 100.54 ± 14.07 nm (AuNPs) and 129.51 ± 12.31 nm (AgNPs), respectively. C1-AuNPs and C1-AgNPs were discovered to have high zeta potentials of -23.29 ± 1.17 and -30.57 ± 0.29 mV, respectively. These nanoparticles have antibacterial properties against several bacterial pathogens. C1-AuNPs and C1-AgNPs significantly inhibited the initial stage biofilm formation and effectively eradicated established mature biofilms of P. aeruginosa and S. aureus. Furthermore, when P. aeruginosa was treated with sub-MIC levels of C1-AuNPs and C1-AgNPs, their different virulence features were significantly reduced. Both NPs greatly inhibited the hemolytic activity of S. aureus. The inhibition of P. aeruginosa and S. aureus biofilms and virulence features by C1-AuNPs and C1-AgNPs can be regarded as viable therapeutic strategies for preventing infections caused by these bacteria.}, } @article {pmid36968011, year = {2023}, author = {Nguyen, HTT and Nguyen, TH and Otto, M}, title = {Corrigendum to "The staphylococcal exopolysaccharide PIA - Biosynthesis and role in biofilm formation, colonization, and infection" [Comput Struct Biotechnol J 4/18 (2020) 3324-3334].}, journal = {Computational and structural biotechnology journal}, volume = {21}, number = {}, pages = {2035}, doi = {10.1016/j.csbj.2023.03.012}, pmid = {36968011}, issn = {2001-0370}, abstract = {[This corrects the article DOI: 10.1016/j.csbj.2020.10.027.].}, } @article {pmid36967885, year = {2023}, author = {He, C and Li, B and Gong, Z and Huang, S and Liu, X and Wang, J and Xie, J and Shi, T}, title = {Polyphosphate kinase 1 is involved in formation, the morphology and ultramicrostructure of biofilm of Mycobacterium smegmatis and its survivability in macrophage.}, journal = {Heliyon}, volume = {9}, number = {3}, pages = {e14513}, pmid = {36967885}, issn = {2405-8440}, abstract = {The most unique characteristic of Mycobacterium tuberculosis is persistence in the human host, and the biofilm formation is related to the persistance. Polyphosphate (polyP) kinase 1 (PPK1) is conserved in Mycobacteria and is responsible for polyP synthesis. polyP is a chain molecule linked by high-energy phosphate bonds, which is considered to play a very important role in bacterial persistence. However, the relationship of PPK1 and mycobacterial biofilm formation is still adequately unclear. In current study, ppk1-deficient mutant (MT), ppk1-complemented (CT) and wild-type strains of M. smegmatis mc[2] 155 were used to investigate the formation, morphology and ultramicrostructure of the biofilm and to analyze the lipid levels and susceptibility to vancomycin antibiotic. And then WT, MT and CT strains were used to infect macrophages and to analyze the expression levels of various inflammatory factors, respectively. We found that PPK1 was required for M. smegmatis polyP production in vivo and polyP deficiency not only attenuated the biofilm formation, but also altered the phenotype and ultramicrostructure of the biofilm and reduced the cell lipid composition (except for C16.1 and C17.1, most of the fatty acid components from C8-C24). Moreover, the ppk1-deficient mutant was also significantly more sensitive to vancomycin which targets the cell wall, and its ability to survive in macrophages was decreased, which was related to the change of the expression level of inflammatory factors in macrophage. This study demonstrates that the PPK1 can affect the biofilm structure through affecting the content of short chain fatty acid and promote intracellular survival of M. smegmatis by altering the expression of inflammatory factors. These findings establish a basis for investigating the role of PPK1 in the persistence of M. tuberculosis, and provide clues for treating latent infection of M. tuberculosis with PPK1 as a potential drug target.}, } @article {pmid36967503, year = {2023}, author = {Majeed, N and Ismail, F}, title = {In vitro characteristics of fungal biofilm formation and the influence of physiological stress on biofilm growth.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {36}, number = {1}, pages = {103-109}, pmid = {36967503}, issn = {1011-601X}, mesh = {*Candida albicans/physiology ; *Gentian Violet ; Oxidative Stress ; Biofilms ; }, abstract = {Fungal biofilms are a growing clinical concern associated with high mortality rates. This study included three fungal groups, dimorphic fungi (Candida albicans), Dermatophytes (Trichophyton mentagrophytes) and non-dermatophytes (Acremonium sclerotigenum, Aspergillus niger). This research describes the in vitro characteristics of biofilm formation in three fungal groups. The influence of osmotic, oxidative and pH stress environment on biofilm growth was also focused. Biofilm characteristics in A. sclerotigenum and A. niger were studied for the first time. In vitro qualitative and quantitative approaches were used to evaluate biofilm development including the test tube method, tissue culture plate method in addition to staining with crystal violet and safranin. All the isolates were able to form biofilm. Biofilm development under different pH range showed maximum growth at neutral pH. At a concentration of 5mM hydrogen peroxide and 2M NaCl biofilm formation was maximum for all three fungal groups under an oxidative and osmotic stress respectively. Study revealed that biofilm production was increased under osmotic and oxidative stress. All isolates respond to oxidative and osmotic stress by changing the cell wall composition with a rich exopolymeric matrix in order to survive in stress environment.}, } @article {pmid36966927, year = {2023}, author = {Liu, Q and Hou, J and Zeng, Y and Wu, J and Miao, L and Yang, Z}, title = {Fabrication of an intimately coupled photocatalysis and biofilm system for removing sulfamethoxazole from wastewater: Effectiveness, degradation pathway and microbial community analysis.}, journal = {Chemosphere}, volume = {328}, number = {}, pages = {138507}, doi = {10.1016/j.chemosphere.2023.138507}, pmid = {36966927}, issn = {1879-1298}, mesh = {*Wastewater ; Sulfamethoxazole/metabolism ; Anti-Bacterial Agents/metabolism ; Biodegradation, Environmental ; *Microbiota ; Biofilms ; }, abstract = {Sulfamethoxazole (SMX) is an extensively applied antibiotic frequently detected in municipal wastewater, which cannot be efficiently removed by conventional biological wastewater processes. In this work, an intimately coupled photocatalysis and biodegradation (ICPB) system consisting of Fe[3+]-doped graphitic carbon nitride photocatalyst and biofilm carriers was fabricated to remove SMX. The results of wastewater treatment experiments showed that 81.2 ± 2.1% of SMX was removed in the ICPB system during the 12 h, while only 23.7 ± 4.0% was removed in the biofilm system within the same time. In the ICPB system, photocatalysis played a key role in removing SMX by producing hydroxyl radicals and superoxide radicals. Besides, the synergism between photocatalysis and biodegradation enhanced the mineralization of SMX. To understand the degradation process of SMX, nine degradation products and possible degradation pathways of SMX were analyzed. The results of high throughput sequencing showed that the diversity, abundance, and structure of the biofilm microbial community remained stable in the ICPB system at the end of the experiments, which suggested that microorganisms had accommodated to the environment of the ICPB system. This study could provide insights into the application of the ICPB system in treating antibiotic-contaminated wastewater.}, } @article {pmid36966821, year = {2023}, author = {Zhang, H and Gong, W and Xue, Y and Zeng, W and Wang, H and Wang, J and Tang, X and Li, G and Liang, H}, title = {Municipal wastewater contains antibiotic treatment using O2 transfer membrane based biofilm reactor: Interaction between regular pollutants metabolism and sulfamethoxazole degradation.}, journal = {The Science of the total environment}, volume = {879}, number = {}, pages = {163060}, doi = {10.1016/j.scitotenv.2023.163060}, pmid = {36966821}, issn = {1879-1026}, mesh = {*Sulfamethoxazole/metabolism ; *Wastewater ; Bioreactors/microbiology ; Anti-Bacterial Agents ; Biofilms ; }, abstract = {The antibiotic sulfamethoxazole (SMX) is frequently detected in wastewater treatment plant effluents and has attracted significant attention owing to its significant potential environmental effects. We present a novel O2 transfer membrane based biofilm reactor (O2TM-BR) to treat municipal wastewater to eliminate containing SMX. Furthermore, conducting metagenomics analyses, the interactions in biodegradation process between SMX and regular pollutants (NH4[+]-N and COD) were studied. Results suggest that O2TM-BR yields evident advantages in SMX degradation. Increasing SMX concentrations did not affect the efficiency of the system, and the effluent concentration remained consistent at approximately 17.0 μg/L. The interaction experiment showed that heterotrophic bacteria tend to consume easily degradable COD for metabolism, resulting in a delay (>36 h) in complete SMX degradation, which is 3-times longer than without COD. It is worth noting that the taxonomic and functional structure and composition in nitrogen metabolism were significantly shifted upon the SMX. NH4[+]-N removal remained unaffected by SMX in O2TM-BR, and the expression of K10944 and K10535 has no significant difference under the stress of SMX (P > 0.02). However, the K00376 and K02567 required in the nitrate reductase is inhibited by SMX (P < 0.01), which hinders the reduction of NO3[-]-N and hence the accumulation of TN. This study provides a new method for SMX treatment and reveals the interaction between SMX and conventional pollutants in O2TM-BR as well as the microbial community function and assembly mechanism.}, } @article {pmid36965588, year = {2023}, author = {Zhong, J and Liu, J and Hu, R and Pan, D and Shao, S and Wu, X}, title = {Performance of nitrification-denitrification and denitrifying phosphorus removal driven by in-situ generated biogenic manganese oxides in a moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {377}, number = {}, pages = {128957}, doi = {10.1016/j.biortech.2023.128957}, pmid = {36965588}, issn = {1873-2976}, mesh = {*Nitrification ; *Waste Disposal, Fluid/methods ; Denitrification ; Manganese ; Biofilms ; Extracellular Polymeric Substance Matrix ; Phosphorus ; Bioreactors ; Oxides ; Nitrogen ; }, abstract = {Simultaneous removal of NH4[+]-N, NO3[-]-N, COD, and P by manganese redox cycling in nutrient wastewater was established with two moving bed biofilm reactors (MBBRs) with in-situ generated biogenic manganese oxides (BioMnOx) and non-BioMnOx. In-situ generated BioMnOx preferentially promoted the denitrification, and the average removal of NO3[-]-N, NH4[+]-N, and TN in the experimental MBBR with BioMnOx increased to 89.00%, 70.64%, and 76.06% compared with the control MBBR with non-BioMnOx. The relevant enzymes activity, extracellular polymeric substance (EPS), electron transport system activity (ETSA), and reactive oxygen species (ROS) were investigated. The element valence and morphology of purified BioMnOx were characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), as well as the effect of BioMnOx on nitrogen and phosphorus removal. The results suggested that BioMnOx could improve nitrogen conversion. Electrochemical characteristic and microbial community were detected. This study provided a new strategy for nutrients removal in BioMnOx-mediated wastewater treatment.}, } @article {pmid36965431, year = {2023}, author = {Gao, S and Sun, Y and Lu, Z and Jiang, N and Yao, H}, title = {Synergistic antibacterial and biofilm eradication activity of quaternary-ammonium compound with copper ion.}, journal = {Journal of inorganic biochemistry}, volume = {243}, number = {}, pages = {112190}, doi = {10.1016/j.jinorgbio.2023.112190}, pmid = {36965431}, issn = {1873-3344}, mesh = {*Copper/pharmacology ; Staphylococcus aureus ; Quaternary Ammonium Compounds/pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Microbial Sensitivity Tests ; *Methicillin-Resistant Staphylococcus aureus ; }, abstract = {Antibiotics overuse and misuse increase the emergence of multidrug-resistant bacterial strains, which often leads to the failure of conventional antibiotic therapies. Even worse, the tendency of bacteria to form biofilms further increases the therapeutic difficulty, because the extracellular matrix prevents the penetration of antibiotics and triggers bacterial tolerance. Therefore, developing novel antibacterial agents or therapeutic strategies with diverse antibacterial mechanisms and destruction of bacteria biofilm is a promising way to combat bacterial infections. In the present study, the combination of quaternary ammonium compound poly(diallyl dimethyl ammonium chloride) (PDDA) with Cu[2+] was screened out to fight common pathogenic Staphylococcus aureus (S. aureus) through multi-mechanisms. This combination appeared strong synergistic antibacterial activity, and the fractional inhibitory concentration index was as low as 0.032. The synergistic antibacterial mechanism involved the destruction of the membrane function, generation of intracellular reactive oxygen, and promotion more Cu[2+] into the cytoplasm. Further, the combination of PDDA and Cu[2+] reduced the extracellular polysaccharide matrix, meanwhile killing the bacteria embedded in the biofilm. The biocompatibility study in vitro revealed this combination exhibited low cytotoxicity and hemolysis ratio even at 8 times of minimum bactericidal concentration. This work provides a novel antibacterial agents combination with higher efficiency to fight planktonic and biofilm conditions of S. aureus.}, } @article {pmid36965425, year = {2023}, author = {Zhang, X and Ji, B and Tian, J and Liu, Y}, title = {Development, performance and microbial community analysis of a continuous-flow microalgal-bacterial biofilm photoreactor for municipal wastewater treatment.}, journal = {Journal of environmental management}, volume = {338}, number = {}, pages = {117770}, doi = {10.1016/j.jenvman.2023.117770}, pmid = {36965425}, issn = {1095-8630}, mesh = {Wastewater ; *Microalgae ; *Water Purification/methods ; Chlorophyll ; Phosphorus ; Bacteria ; Biofilms ; Nitrogen ; Biomass ; }, abstract = {This work reported the development, performance and microbial community of microalgal-bacterial biofilms cultivated in a continuous-flow photoreactor for municipal wastewater treatment under various conditions. Results showed that microalgal-bacterial biofilms were successfully developed at a HRT of 9 h without external aeration, with a biofilm concentration of around 4690 mg/L being achieved in the steady-state. It was found that further increase of HRT to 12 h did not improve the overall accumulation of biofilm, whereas the growth of microalgae in biofilms was faster than bacteria in the initial stage, indicated by an increased chlorophyll-a&b content in biofilms. After which, the chlorophyll-a&b content in biofilms gradually stabilized at the level comparable with the seed, suggesting that there was a balanced distribution of microalgae and bacteria in biofilms. About 90% of TOC, 71.4% of total nitrogen and 72.6% of phosphorus were removed by microalgal-bacterial biofilms mainly through assimilation in the steady-state photoreactor run at the HRT of 12 h with external aeration. The community analysis further revealed that Cyanobacteria and Chloroflexi were the main components, while Chlorophyta appeared to be the dominant eukaryotic algal community in biofilms. This study could offer new insights into the development of microalgal-bacterial biofilms in a continuous-flow photoreactor for sustainable low-carbon municipal wastewater treatment.}, } @article {pmid36963701, year = {2023}, author = {Zhao, J and Dong, X and Su, H and Huang, J and Liu, Z and He, P and Zhang, D}, title = {Rapid start-up of PN/A process and efficient enrichment of functional bacteria: A novel aerobic-biofilm/anaerobic-granular nitrogen removal system (OANRS).}, journal = {Bioresource technology}, volume = {380}, number = {}, pages = {128944}, doi = {10.1016/j.biortech.2023.128944}, pmid = {36963701}, issn = {1873-2976}, mesh = {*Nitrification ; *Denitrification ; Nitrogen ; Anaerobiosis ; Anaerobic Ammonia Oxidation ; Bioreactors/microbiology ; Oxidation-Reduction ; Bacteria/genetics ; Biofilms ; Sewage ; }, abstract = {Reactor configuration, control strategy and inoculation method were key factors affecting the rapid start-up of partial nitrification/anammox (PN/A) process and the efficient enrichment of functional bacteria (anammox and ammonia oxidizing bacteria). At present, PN/A process was generally operated through single factor rather than forming a system. In this study, a novel aerobic-biofilm/anaerobic-granular nitrogen removal system (OANRS) was constructed, which consisted of a multi-stage aerobic-biofilm/anaerobic-granular baffle reactor (MOABR) and a control strategy on pH/aeration time. PN process was started within 10d, and PN/A process was started on the basis of stable PN process within 41d. The simultaneous enrichment of functional bacteria was achieved by combining the advantages of single-stage and two-stage PN/A process. The results of high-throughput sequencing showed that Candidatus Kuenenia (20.42 ± 15.88%) was highly enriched in each compartment at day 98, and the relative abundance of Candidatus Kuenenia in the anaerobic compartment R4 was as high as 43.13%.}, } @article {pmid36963576, year = {2023}, author = {Li, M and Perez-Calleja, P and Kim, B and Picioreanu, C and Nerenberg, R}, title = {Unique stratification of biofilm density in heterotrophic membrane-aerated biofilms: An experimental and modeling study.}, journal = {Chemosphere}, volume = {327}, number = {}, pages = {138501}, doi = {10.1016/j.chemosphere.2023.138501}, pmid = {36963576}, issn = {1879-1298}, mesh = {*Bioreactors ; *Biofilms ; Extracellular Polymeric Substance Matrix ; Membranes ; Oxygen ; }, abstract = {We consistently find a band of high cell density develop within heterotrophic membrane-aerated biofilms. This study reports and attempts to explain this unique behavior. Biofilm density affects volumetric reaction rates, biofilm growth rates, substrate diffusion, and mechanical behavior. Yet the mechanisms and dynamics of biofilm density development are poorly understood. In this study, a membrane-aerated biofilm, where O2 was supplied from the base of the biofilm and acetate from the bulk liquid, was used to explore spatial and temporal patterns of density development. Biofilm density was assessed by optical coherence tomography. After inoculation, the biofilm quickly increased in thickness, with a low density throughout. However, as the biofilm reached a stable thickness of around 1000 μm, a high-density layer developed in the biofilm interior. The layer slowly expanded over time. Oxygen microprofiles in the biofilm showed this layer coincided with the most metabolically active zone, resulting from counter-diffusing O2 and acetate. The formation of this dense layer appeared to be related to changes in growth rates. Initially, high growth rates throughout the biofilm presumably led to fast-growing, low-density biofilms. As the biofilm became thicker, and as substrates became limiting in the biofilm interior, growth rates decreased, resulting in new growth at a higher density. A 1-D mathematical model with variable biofilm density was developed by linking the rates of extracellular polymeric substances (EPS) production to the growth rate. The model captured the initial fast growth at a low density, followed by a slower, substrate-limited growth in the biofilm interior, producing a dense band within the biofilm. Together, these results suggest that low growth rates can lead to high-density zones within the interior of counter-diffusional biofilms. These findings should also be relevant to conventional, co-diffusional biofilms, although differences in density may be less obvious.}, } @article {pmid36960491, year = {2023}, author = {Johnston, W and Rosier, BT and Carda-Diéguez, M and Paterson, M and Watson, P and Piela, K and Goulding, M and Ramage, G and Baranyia, D and Chen, T and Al-Hebshi, NN and Mira, A and Culshaw, S}, title = {Longitudinal changes in subgingival biofilm composition following periodontal treatment.}, journal = {Journal of periodontology}, volume = {}, number = {}, pages = {}, doi = {10.1002/JPER.22-0749}, pmid = {36960491}, issn = {1943-3670}, support = {1R03DE028379-01A1/DE/NIDCR NIH HHS/United States ; }, abstract = {BACKGROUND: Current periodontal treatment involves instrumentation using hand and/or ultrasonic instruments, which are used either alone or in combination based on patient and clinician preference, with comparable clinical outcomes. This study sought to investigate early and later changes in the subgingival biofilm following periodontal treatment, to identify whether these changes were associated with treatment outcomes, and to investigate whether the biofilm responded differently to hand compared with ultrasonic instruments.

METHODS: This was a secondary-outcome analysis of a randomized-controlled trial. Thirty-eight periodontitis patients received full-mouth subgingival instrumentation using hand (n = 20) or ultrasonic instrumentation (n = 18). Subgingival plaque was sampled at baseline and 1, 7, and 90 days following treatment. Bacterial DNA was analyzed using 16S rRNA sequencing. Periodontal clinical parameters were evaluated before and after treatment.

RESULTS: Biofilm composition was comparable in both (hand and ultrasonics) treatment groups at all time points (all genera and species; p[adjusted] > 0.05). Large-scale changes were observed within groups across time points. At days 1 and 7, taxonomic diversity and dysbiosis were reduced, with an increase in health-associated genera including Streptococcus and Rothia equating to 30% to 40% of the relative abundance. When reassessed at day 90 a subset of samples reformed a microbiome more comparable with baseline, which was independent of instrumentation choice and residual disease.

CONCLUSIONS: Hand and ultrasonic instruments induced comparable impacts on the subgingival plaque microbiome. There were marked early changes in the subgingival biofilm composition, although there was limited evidence that community shifts associated with treatment outcomes.}, } @article {pmid36959476, year = {2023}, author = {Kilic, T and Bali, EB}, title = {Biofilm control strategies in the light of biofilm-forming microorganisms.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {5}, pages = {131}, pmid = {36959476}, issn = {1573-0972}, mesh = {Humans ; *Biofilms ; Quorum Sensing ; Bacteria ; *Bacterial Infections/drug therapy ; Polysaccharides ; }, abstract = {Biofilm is a complex consortium of microorganisms attached to biotic or abiotic surfaces and live in self-produced or acquired extracellular polymeric substances (EPSs). EPSs are mainly formed by lipids, polysaccharides, proteins, and extracellular DNAs. The adherence to the surface of microbial communities is seen in food, medical, dental, industrial, and environmental fields. Biofilm development in food processing areas challenges food hygiene, and human health. In addition, bacterial attachment and biofilm formation on medical implants inside human tissue can cause multiple critical chronic infections. More than 30 years of international research on the mechanisms of biofilm formation have been underway to address concerns about bacterial biofilm infections. Antibiofilm strategies contain cold atmospheric plasma, nanotechnological, phage-based, antimicrobial peptides, and quorum sensing inhibition. In the last years, the studies on environmentally-friendly techniques such as essential oils and bacteriophages have been intensified to reduce microbial growth. However, the mechanisms of the biofilm matrix formation are still unclear. This review aims to discuss the latest antibiofilm therapeutic strategies against biofilm-forming bacteria.}, } @article {pmid36959215, year = {2023}, author = {Bech, PK and Zhang, SD and Henriksen, NNSE and Bentzon-Tilia, M and Strube, ML and Gram, L}, title = {The potential to produce tropodithietic acid by Phaeobacter inhibens affects the assembly of microbial biofilm communities in natural seawater.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {12}, pmid = {36959215}, issn = {2055-5008}, mesh = {*Biofilms ; *Microbiota ; Anti-Bacterial Agents ; Seawater ; }, abstract = {Microbial secondary metabolites play important roles in biotic interactions in microbial communities and yet, we do not understand how these compounds impact the assembly and development of microbial communities. To address the implications of microbial secondary metabolite production on biotic interactions in the assembly of natural seawater microbiomes, we constructed a model system where the assembly of a natural seawater biofilm community was influenced by the addition of the marine biofilm forming Phaeobacter inhibens that can produce the antibiotic secondary metabolite tropodithietic acid (TDA), or a mutant incapable of TDA production. Because of the broad antibiotic activity of TDA, we hypothesized that the potential of P. inhibens to produce TDA would strongly affect both biofilm and planktonic community assembly patterns. We show that 1.9 % of the microbial composition variance across both environments could be attributed to the presence of WT P. inhibens, and especially genera of the Bacteriodetes were increased by the presence of the TDA producer. Moreover, network analysis with inferred putative microbial interactions revealed that P. inhibens mainly displayed strong positive associations with genera of the Flavobacteriaceae and Alteromonadaceae, and that P. inhibens acts as a keystone OTU in the biofilm exclusively due to its potential to produce TDA. Our results demonstrate the potential impact of microbial secondary metabolites on microbial interactions and assembly dynamics of complex microbial communities.}, } @article {pmid36950165, year = {2023}, author = {Racioppo, A and Speranza, B and Altieri, C and Sinigaglia, M and Corbo, MR and Bevilacqua, A}, title = {Ultrasound can increase biofilm formation by Lactiplantibacillus plantarum and Bifidobacterium spp.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1094671}, pmid = {36950165}, issn = {1664-302X}, abstract = {The main goal of this research was to study the effect of an Ultrasound (US) treatment on biofilm formation of Lactiplantibacillus plantarum (strains c19 and DSM 1055), Bifidobacterium animalis subsp. lactis DSM 10140, Bifidobacterium longum subsp. longum DSM 20219, and Bifidobacterium longum subsp. infantis DSM 20088. From a methodological point of view, each microorganism was treated through six US treatments, different for the power (10, 30, or 50% of the net power, 130 W), the duration (2, 6, or 10 min) and the application of pulses (0 or 10 s). After the treatment, a biofilm of the strains was let to form on glass slides and the concentration of sessile cells was analyzed for 16 days. Biofilms formed by untreated microorganisms were used as controls. As a first result, it was found that US significantly increased the concentration of sessile cells of B. longum subsp. infantis, while for some other strains US treatment could not affect the formation of biofilm while improving its stability, as found for L. plantarum DSM1055 after 16 days. The variable mainly involved in this positive effect of US was the duration of the treatment, as biofilm formation and stability were improved only for 2 min-treatments; on the other hand, the effect of power and pulses were strain-dependent. In conclusion, the results suggest practical implication of a US pre-treatment for various fields (improvement of adhesion of microorganisms useful in food or in the gut, biomedical and environmental industries), although further investigations are required to elucidate the mode of action.}, } @article {pmid36950159, year = {2023}, author = {Liang, J and Huang, TY and Mao, Y and Li, X}, title = {Biofilm formation of two genetically diverse Staphylococcus aureus isolates under beta-lactam antibiotics.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1139753}, pmid = {36950159}, issn = {1664-302X}, abstract = {PURPOSE: Our aim was to evaluate the biofilm formation of 2 genetically diverse Staphylococcus aureus isolates, 10379 and 121940, under different concentrations of beta-lactam antibiotics on biomass content and biofilm viability.

METHODS: Biofilm formation and methicillin resistance genes were tested using PCR and multiplex PCR. PCR was combined with bioinformatics analysis to detect multilocal sequence typing (MLST) and SCCmec types, to study the genetical correlation between the tested strains. Then, the crystal violet (CV) test and XTT were used to detect biomass content and biofilm activity. Antibiotic susceptibility was tested using a broth dilution method. According to their specific MIC, different concentrations of beta-lactam antibiotics were used to study its effect on biomass content and biofilm viability.

RESULTS: Strain 10379 carried the icaD, icaBC, and MRSA genes, not the icaA, atl, app, and agr genes, and MLST and SCCmec typing was ST45 and IV, respectively. Strain 121940 carried the icaA, icaD, icaBC, atl, and agr genes, not the aap gene, and MLST and SCCmec typed as ST546 and IV, respectively. This suggested that strains 10379 and 121940 were genotypically very different. Two S. aureus isolates, 10379 and 121940, showed resistance to beta-lactam antibiotics, penicillin, ampicillin, meropenem, streptomycin and kanamycin, some of which promoted the formation of biofilm and biofilm viability at low concentrations.

CONCLUSION: Despite the large differences in the genetic background of S. aureus 10379 and 121940, some sub-inhibitory concentrations of beta-lactam antibiotics are able to promote biomass and biofilm viability of both two isolates.}, } @article {pmid36948593, year = {2023}, author = {Wang, M and Wang, J and Li, T and Bao, X and Li, P and Zhang, X and Huang, Q and Meng, X and Li, S}, title = {Penicillin-binding protein 1b encoded by mrcB gene mediates the enhancement of biofilm formation by subinhibitory concentrations of cefotaxime in monophasic Salmonella Typhimurium strain SH16SP46.}, journal = {FEMS microbiology letters}, volume = {370}, number = {}, pages = {}, doi = {10.1093/femsle/fnad021}, pmid = {36948593}, issn = {1574-6968}, mesh = {Penicillin-Binding Proteins/genetics ; *Cefotaxime/pharmacology ; *Salmonella typhimurium/genetics ; Microbial Sensitivity Tests ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Development of cefotaxime-resistance and biofilm formation increase the difficulty to prevent and control the infection and contamination of Salmonella, one of the most important foodborne and zoonotic bacterial pathogen. Our previous study observed that 1/8 minimum inhibitory concentration (MIC) of cefotaxime induced the enhancement of biofilm formation and filamentous morphological change by a monophasic Salmonella Typhimurium strain SH16SP46. This study was designed to explore the role of three penicillin-binding proteins (PBPs) in mediating the induction effect of cefotaxime. Three deletion mutants of the genes mrcA, mrcB, and ftsI, encoding the proteins PBP1a, PBP1b, and PBP3, respectively, were constructed using the parental Salmonella strain SH16SP46. Gram staining and scanning electron microscopy showed that these mutants showed normal morphology comparable to the parental strain without cefotaxime treatment. However, under the stress of 1/8 MIC of cefotaxime, the strains WT, ΔmrcA, and ΔftsI, rather than ΔmrcB, exhibited filamentous morphological change. Moreover, cefotaxime treatment significantly enhanced biofilm formation by the strains WT, ΔmrcA, and ΔftsI, but not by the ΔmrcB strain. The complement of mrcB gene in the ΔmrcB strain recovered the enhanced biofilm formation and filamentous morphological change induced by cefotaxime. Our results suggest that PBP1b encoded by mrcB gene may be a binding target of cefotaxime for initiating the effect on Salmonella morphology and biofilm formation. The study will contribute to further understanding of the regulatory mechanism of cefotaxime on Salmonella biofilm formation.}, } @article {pmid36948321, year = {2023}, author = {Cheng, L and Yang, W and Liang, H and Nabi, M and Li, Y and Wang, H and Hu, J and Chen, T and Gao, D}, title = {Nitrogen removal from mature landfill leachate through enhanced Partial Nitrification-Anammox process in an innovative multi-stage fixed biofilm reactor.}, journal = {The Science of the total environment}, volume = {877}, number = {}, pages = {162959}, doi = {10.1016/j.scitotenv.2023.162959}, pmid = {36948321}, issn = {1879-1026}, mesh = {*Nitrification ; Denitrification ; *Water Pollutants, Chemical ; Nitrogen ; Anaerobic Ammonia Oxidation ; Bioreactors ; Oxidation-Reduction ; Sewage ; }, abstract = {In the current integrated PN/A method/process for mature landfill leachate treatment, microbial inhibition and low nitrogen removal capacity are the big barriers due to high ammonia concentration and low C/N. This study aimed to evaluate the performance of a high-rate nitrogen removal lab-scale reactor, which combines pre-denitrification and Partial Nitrification-Anammox (PN/A) in a multi-stage fixed biofilm reactor (MFBR), for mature landfill leachate treatment. A nitrogen removal efficiency (NRE) of 90.43 % and an average nitrogen removal rate (NRR) of 0.94 kg/m[3]·d were observed at an influent NH+ 4-N concentration of 2274.39 mg/L during the last operational phase. The nitrogen mass balance showed that the nitrogen concentration gradually decreases along the course, and nitrogen was mainly removed in the aerobic chambers, in which Anammox contributed to 86.4 % of the removed nitrogen, while the front anoxic chamber is mainly used to remove NO- 3-N from the recirculation. Redundancy analysis showed that the variation in NH+ 4-N concentration along the course was the main factor affecting microbial community succession, which shows that the reactor configuration enables efficient cooperation and distribution of different microorganisms. Moreover, economic analysis of MFBR process showed that the energy consumption and carbon addition were reduced by 58.9 % and 100 %, respectively. Therefore, the MFBR established in this study, with its new configuration, achieves efficient treatment of landfill leachate in a single reactor and is environmentally friendly, and could be considered as a reference for full-scale landfill leachate treatment.}, } @article {pmid36947926, year = {2023}, author = {Wu, M and Lai, CY and Wang, Y and Yuan, Z and Guo, J}, title = {Microbial nitrate reduction in propane- or butane-based membrane biofilm reactors under oxygen-limiting conditions.}, journal = {Water research}, volume = {235}, number = {}, pages = {119887}, doi = {10.1016/j.watres.2023.119887}, pmid = {36947926}, issn = {1879-2448}, mesh = {Humans ; *Propane ; *Nitrates ; Natural Gas ; RNA, Ribosomal, 16S ; Alkanes ; Methane ; Butanes ; Oxidation-Reduction ; Biofilms ; Oxygen ; Water ; Bioreactors ; }, abstract = {Nitrate contamination has been commonly detected in water environments and poses serious hazards to human health. Previously methane was proposed as a promising electron donor to remove nitrate from contaminated water. Compared with pure methane, natural gas, which not only contains methane but also other short chain gaseous alkanes (SCGAs), is less expensive and more widely available, representing a more attractive electron source for removing oxidized contaminants. However, it remains unknown if these SCGAs can be utilized as electron donors for nitrate reduction. Here, two lab-scale membrane biofilm reactors (MBfRs) separately supplied with propane and butane were operated under oxygen-limiting conditions to test its feasibility of microbial nitrate reduction. Long-term performance suggested nitrate could be continuously removed at a rate of ∼40-50 mg N/L/d using propane/butane as electron donors. In the absence of propane/butane, nitrate removal rates significantly decreased both in the long-term operation (∼2-10 and ∼4-9 mg N/L/d for propane- and butane-based MBfRs, respectively) and batch tests, indicating nitrate bio-reduction was driven by propane/butane. The consumption rates of nitrate and propane/butane dramatically decreased under anaerobic conditions, but recovered after resupplying limited oxygen, suggesting oxygen was an essential triggering factor for propane/butane-based nitrate reduction. High-throughput sequencing targeting 16S rRNA, bmoX and narG genes indicated Mycobacterium/Rhodococcus/Thauera were the potential microorganisms oxidizing propane/butane, while various denitrifiers (e.g. Dechloromonas, Denitratisoma, Zoogloea, Acidovorax, Variovorax, Pseudogulbenkiania and Rhodanobacter) might perform nitrate reduction in the biofilms. Our findings provide evidence to link SCGA oxidation with nitrate reduction under oxygen-limiting conditions and may ultimately facilitate the design of cost-effective techniques for ex-situ groundwater remediation using natural gas.}, } @article {pmid36947565, year = {2023}, author = {Trindade, SC and Lopes, MPP and Oliveira, TTMC and Silva, MJ and Queiroz, GA and Jesus, TS and Santos, EKN and Carvalho-Filho, PC and Falcão, MML and Miranda, PM and Santos, RPB and Figueiredo, CA and Cruz, ÁA and Seymour, GJ and Gomes-Filho, IS}, title = {Single nucleotide variants in the IL33 and IL1RL1 (ST2) genes are associated with periodontitis and with Aggregatibacter actinomycetemcomitans in the dental plaque biofilm: A putative role in understanding the host immune response in periodontitis.}, journal = {PloS one}, volume = {18}, number = {3}, pages = {e0283179}, pmid = {36947565}, issn = {1932-6203}, mesh = {Humans ; Aggregatibacter actinomycetemcomitans/genetics ; Biofilms ; Cross-Sectional Studies ; *Dental Plaque/genetics ; Immunity ; *Interleukin-1 Receptor-Like 1 Protein/genetics ; *Interleukin-33/genetics ; Nucleotides ; *Periodontitis/genetics ; Polymorphism, Single Nucleotide ; }, abstract = {The Interleukin (IL)-33 is important in several inflammatory diseases and its cellular receptor is the Interleukin 1 receptor-like 1 (IL1RL1), also called suppression of tumorigenicity 2 ligand (ST2L). This study investigated associations between single nucleotide variants (SNVs) in the IL33 gene and in the IL1RL1 (ST2) gene with periodontitis. Additionally, aimed to determine the role of Aggregatibacter actinomycetemcomitans (Aa) relative amount in the subgingival biofilm in these associations. A cross-sectional study was carried out with 506 individuals that answered a structured questionnaire used to collect their health status, socioeconomic-demographic, and behavioral characteristics. Periodontal examination was performed to determine the presence and severity of periodontitis, and subgingival biofilm samples were collected to quantify the relative amount of Aa by real time polymerase chain reaction. Human genomic DNA was extracted from whole blood cells and SNV genotyping was performed. Logistic regression estimated the association measurements, odds ratio (OR), and 95% confidence interval (95%CI), between the IL33 and ST2 genes with periodontitis, and subgroup analyses assessed the relative amount of Aa in these associations. 23% of individuals had periodontitis. Adjusted measurements showed a statistically significant inverse association between two SNVs of the ST2; rs148548829 (C allele) and rs10206753 (G allele). These two alleles together with a third SNV, the rs11693204 (A allele), were inversely associated with moderate periodontitis. One SNV of the IL33 gene also showed a statistically significant inverse association with moderate periodontitis. Nine SNVs of the ST2 gene were inversely associated with the relative amount of Aa. In the high Aa subgroup, there was a direct association between 11 SNVs of the ST2 gene and moderate periodontitis and two SNVs of the ST2 gene and severe periodontitis, and eight SNVs of the ST2 gene and periodontitis. These exploratory findings of genetic variants in IL-33/ST2 axis support the concept that the different tissue responses among individuals with periodontitis may be modulated by the host's genetics, influencing the physiopathology of the disease.}, } @article {pmid36946779, year = {2023}, author = {Johnston, EL and Zavan, L and Bitto, NJ and Petrovski, S and Hill, AF and Kaparakis-Liaskos, M}, title = {Planktonic and Biofilm-Derived Pseudomonas aeruginosa Outer Membrane Vesicles Facilitate Horizontal Gene Transfer of Plasmid DNA.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0517922}, pmid = {36946779}, issn = {2165-0497}, abstract = {Outer membrane vesicles (OMVs) produced by Gram-negative bacteria package various cargo, including DNA that can be transferred to other bacteria or to host cells. OMV-associated DNA has been implicated in mediating horizontal gene transfer (HGT) between bacteria, which includes the dissemination of antibiotic resistance genes within and between bacterial species. Despite the known ability of OMVs to mediate HGT, the mechanisms of DNA packaging into OMVs remain poorly characterized, as does the effect of bacterial growth conditions on the DNA cargo composition of OMVs and their subsequent abilities to mediate HGT. In this study, we examined the DNA content of OMVs produced by the opportunistic pathogen Pseudomonas aeruginosa grown in either planktonic or biofilm conditions. Analysis of planktonic growth-derived OMVs revealed their ability to package and protect plasmid DNA from DNase degradation and to transfer plasmid-encoded antibiotic resistance genes to recipient, antibiotic-sensitive P. aeruginosa bacteria at a greater efficiency than transformation with plasmid alone. Comparisons of planktonic and biofilm-derived P. aeruginosa OMVs demonstrated that biofilm-derived OMVs were smaller but were associated with more plasmid DNA than planktonic-derived OMVs. Additionally, biofilm-derived P. aeruginosa OMVs were more efficient in the transformation of competent P. aeruginosa bacteria, compared to transformations with an equivalent number of planktonic-derived OMVs. The findings of this study highlight the importance of bacterial growth conditions for the packaging of DNA within P. aeruginosa OMVs and their ability to facilitate HGT, thus contributing to the spread of antibiotic resistance genes between P. aeruginosa bacteria. IMPORTANCE Bacterial membrane vesicles (BMVs) mediate interbacterial communication, and their ability to package DNA specifically contributes to biofilm formation, antibiotic resistance, and HGT between bacteria. However, the ability of P. aeruginosa OMVs to mediate HGT has not yet been demonstrated. Here, we reveal that P. aeruginosa planktonic and biofilm-derived OMVs can deliver plasmid-encoded antibiotic resistance to recipient P. aeruginosa. Additionally, we demonstrated that P. aeruginosa biofilm-derived OMVs were associated with more plasmid DNA compared to planktonic-derived OMVs and were more efficient in the transfer of plasmid DNA to recipient bacteria. Overall, this demonstrated the ability of P. aeruginosa OMVs to facilitate the dissemination of antibiotic resistance genes, thereby enabling the survival of susceptible bacteria during antibiotic treatment. Investigating the roles of biofilm-derived BMVs may contribute to furthering our understanding of the role of BMVs in HGT and the spread of antibiotic resistance in the environment.}, } @article {pmid36946276, year = {2023}, author = {Sójka, O and Keskin, D and van der Mei, HC and van Rijn, P and Gagliano, MC}, title = {Nanogel-based coating as an alternative strategy for biofilm control in drinking water distribution systems.}, journal = {Biofouling}, volume = {39}, number = {2}, pages = {121-134}, doi = {10.1080/08927014.2023.2190023}, pmid = {36946276}, issn = {1029-2454}, mesh = {*Drinking Water/microbiology ; Nanogels ; Biofilms ; Bacteria ; }, abstract = {Biofilm formation and detachment in drinking water distribution systems (DWDS) can lead to several operational issues. Here, an alternative biofilm control strategy of limiting bacterial adhesion by application of a poly(N-isopropylmethacrylamide)-based nanogel coating on DWDS pipe walls was investigated. The nanogel coatings were successfully deposited on surfaces of four polymeric pipe materials commonly applied in DWDS construction. Nanogel-coated and non-coated pipe materials were characterized in terms of their surface hydrophilicity and roughness. Four DWDS relevant bacterial strains, representing Sphingomonas and Pseudomonas, were used to evaluate the anti-adhesive performance of the coating in 4 h adhesion and 24 h biofilm assays. The presence of the nanogel coating resulted in adhesion reduction up to 97%, and biofilm reduction up to 98%, compared to non-coated surfaces. These promising results motivate further investigation of nanogel coatings as a strategy for biofilm prevention in DWDS.}, } @article {pmid36946046, year = {2023}, author = {Zhang, Z and Liao, H and Yang, M and Hu, C and DU, Y}, title = {[Levofloxacin combined with cellulase can eradicate bacille Calmette-Guerin biofilm infection].}, journal = {Nan fang yi ke da xue xue bao = Journal of Southern Medical University}, volume = {43}, number = {2}, pages = {257-264}, pmid = {36946046}, issn = {1673-4254}, mesh = {*Levofloxacin/pharmacology ; Gentian Violet/pharmacology ; BCG Vaccine/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cellulases/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {OBJECTIVE: To investigate the inhibitory effects of levofloxacin (LEV) combined with cellulase against bacille CalmetteGuerin (BCG) biofilms in vitro.

METHODS: The mature growth cycle of BCG biofilms was determined using the XTT method and crystal violet staining. BCG planktonic bacteria and BCG biofilms were treated with different concentrations of LEV and cellulose alone or jointly, and the changes in biofilm biomass were quantified with crystal violet staining. The mature BCG biofilm was then treated with cellulase alone for 24 h, and after staining with SYTO 9 and Calcofluor White Stain, the number of viable bacteria and the change in cellulose content in the biofilm were observed with confocal laser scanning microscopy. The structural changes of the treated biofilm were observed under scanning electron microscopy.

RESULTS: The MIC, MBC and MBEC values of LEV determined by broth microdilution method were 4 μg/mL, 8 μg/mL and 1024 μg/mL, respectively. The combined treatment with 1/4×MIC LEV and 2.56, 5.12 or 10.24 U/mL cellulase resulted in a significant reduction in biofilm biomass (P < 0.001). Cellulase treatments at the concentrations of 10.24, 5.12 and 2.56 U/mL all produced significant dispersion effects on mature BCG biofilms (P < 0.001).

CONCLUSION: LEV combined with cellulose can effectively eradicate BCG biofilm infections, suggesting the potential of glycoside hydrolase therapy for improving the efficacy of antibiotics against biofilmassociated infections caused by Mycobacterium tuberculosis.}, } @article {pmid36944677, year = {2023}, author = {Brothers, KM and Parker, DM and Taguchi, M and Ma, D and Mandell, JB and Thurlow, LL and Byrapogu, VC and Urish, KL}, title = {Dose optimization in surgical prophylaxis: sub-inhibitory dosing of vancomycin increases rates of biofilm formation and the rates of surgical site infection.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {4593}, pmid = {36944677}, issn = {2045-2322}, support = {K08 AR071494/AR/NIAMS NIH HHS/United States ; R01 AR082167/AR/NIAMS NIH HHS/United States ; R03 AR077602/AR/NIAMS NIH HHS/United States ; }, mesh = {Animals ; Mice ; Vancomycin/pharmacology/therapeutic use ; Staphylococcus aureus ; Surgical Wound Infection ; Abscess ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Staphylococcal Infections/drug therapy/prevention & control/microbiology ; Biofilms ; Microbial Sensitivity Tests ; *Methicillin-Resistant Staphylococcus aureus ; }, abstract = {Antibiotic stewardship is viewed as having great public health benefit with limited direct benefit to the patient at the time of administration. The objective of our study was to determine if inappropriate administration of antibiotics could create conditions that would increase the rates of surgical infection. We hypothesized that sub-MIC levels of vancomycin would increase Staphylococcus aureus growth, biofilm formation, and rates of infection. S. aureus MRSA and MSSA strains were used for all experiments. Bacteria were grown planktonically and monitored using spectrophotometry. Quantitative agar culture was used to measure planktonic and biofilm bacterial burden. A mouse abscess model was used to confirm phenotypes in vivo. In the planktonic growth assay, increases in bacterial burden at ¼ MIC vancomycin were observed in USA300 JE2 by 72 h. Similar findings were observed with ½ MIC in Newman and SH1000. For biofilm formation, USA300 JE2 at ¼ and ½ MIC vancomycin increased biofilm formation by approximately 1.3- and 2.3-fold respectively at 72 h as compared to untreated controls. Similar findings were observed with Newman and SH1000 with a 2.4-fold increase in biofilm formation at ½ MIC vancomycin. In a mouse abscess model, there was a 1.2-fold increase with sub-MIC vancomycin at 3 days post infection. Our study showed that Sub-optimal vancomycin dosing promoted S. aureus planktonic growth and biofilm formation, phenotypic measures of bacterial virulence. This phenotype induced by sub-MIC levels of vancomycin was also observed to increase rates of infection and pathogenesis in our mouse model. Risks of exposure to sub-MIC concentrations with vancomycin in surgical procedures are greater as there is decreased bioavailability in tissue in comparison to other antibiotics. This highlights the importance of proper antibiotic selection, stewardship, and dosing for both surgical prophylaxis and treatment of infection.}, } @article {pmid36944321, year = {2023}, author = {Kognou, ALM and Chio, C and Khatiwada, JR and Shrestha, S and Chen, X and Zhu, Y and Ngono Ngane, RA and Agbor Agbor, G and Jiang, ZH and Xu, CC and Qin, W}, title = {Characterization of Potential Virulence, Resistance to Antibiotics and Heavy Metals, and Biofilm-forming Capabilities of Soil Lignocellulolytic Bacteria.}, journal = {Microbial physiology}, volume = {}, number = {}, pages = {}, doi = {10.1159/000530228}, pmid = {36944321}, issn = {2673-1673}, abstract = {Soil bacteria participate in self-immobilization processes for survival, persistence and producing virulence factors in some niches or hosts through their capacities of autoaggregation, cell surface hydrophobicity, biofilm formation, and antibiotic and heavy metal resistance. This study investigated potential virulence, antibiotics and heavy metals resistance, solvent adhesion, and biofilm-forming capabilities of six cellulolytic bacteria isolated from soil samples: Paenarthrobacter sp. MKAL1, Hymenobacter sp. MKAL2, Mycobacterium sp. MKAL3, Stenotrophomonas sp. MKAL4, Chryseobacterium sp. MKAL5 and Bacillus sp. MKAL6. Strains were subjected to phenotypic methods, including heavy metal and antibiotic susceptibility and virulence factors (protease, lipase, capsule production, autoaggregation, hydrophobicity and biofilm formation). The effect of ciprofloxacin was also investigated on bacterial susceptibility over time, cell membrane and biofilm formation. Strains MKAL2, MKAL5 and MKAL6 exhibited protease and lipase activities, while only MKAL6 produced capsules. All strains were capable of aggregating, forming biofilm and adhering to solvents. Strains tolerated high amounts of chromium, lead, zinc, nickel and manganese and were resistant to lincomycin. Ciprofloxacin exhibited bactericidal activity against these strains. Although the phenotypic evaluation of virulence factors of bacteria can indicate their pathogenic nature, an in-depth genetic study of virulence, antibiotic and heavy metal resistance genes is required.}, } @article {pmid36942961, year = {2023}, author = {Archambault, L and Koshy-Chenthittayil, S and Thompson, A and Dongari-Bagtzoglou, A and Laubenbacher, R and Mendes, P}, title = {Corrected and Republished from: "Understanding Lactobacillus paracasei and Streptococcus oralis Biofilm Interactions through Agent-Based Modeling".}, journal = {mSphere}, volume = {8}, number = {2}, pages = {e0065622}, pmid = {36942961}, issn = {2379-5042}, support = {R01 DE013986/DE/NIDCR NIH HHS/United States ; }, abstract = {As common commensals residing on mucosal tissues, Lactobacillus species are known to promote health, while some Streptococcus species act to enhance the pathogenicity of other organisms in those environments. In this study we used a combination of in vitro imaging of live biofilms and computational modeling to explore biofilm interactions between Streptococcus oralis, an accessory pathogen in oral candidiasis, and Lactobacillus paracasei, an organism with known probiotic properties. A computational agent-based model was created where the two species interact only by competing for space, oxygen, and glucose. Quantification of bacterial growth in live biofilms indicated that S. oralis biomass and cell numbers were much lower than predicted by the model. Two subsequent models were then created to examine more complex interactions between these species, one where L. paracasei secretes a surfactant and another where L. paracasei secretes an inhibitor of S. oralis growth. We observed that the growth of S. oralis could be affected by both mechanisms. Further biofilm experiments support the hypothesis that L. paracasei may secrete an inhibitor of S. oralis growth, although they do not exclude that a surfactant could also be involved. This contribution shows how agent-based modeling and experiments can be used in synergy to address multiple-species biofilm interactions, with important roles in mucosal health and disease. IMPORTANCE We previously discovered a role of the oral commensal Streptococcus oralis as an accessory pathogen. S. oralis increases the virulence of Candida albicans infections in murine oral candidiasis and epithelial cell models through mechanisms which promote the formation of tissue-damaging biofilms. Lactobacillus species have known inhibitory effects on biofilm formation of many microbes, including Streptococcus species. Agent-based modeling has great advantages as a means of exploring multifaceted relationships between organisms in complex environments such as biofilms. Here, we used an iterative collaborative process between experimentation and modeling to reveal aspects of the mostly unexplored relationship between S. oralis and L. paracasei in biofilm growth. The inhibitory nature of L. paracasei on S. oralis in biofilms may be exploited as a means of preventing or alleviating mucosal fungal infections.}, } @article {pmid36942960, year = {2023}, author = {Archambault, L and Koshy-Chenthittayil, S and Thompson, A and Dongari-Bagtzoglou, A and Laubenbacher, R and Mendes, P}, title = {Correction for Archambault et al., "Understanding Lactobacillus paracasei and Streptococcus oralis Biofilm Interactions through Agent-Based Modeling".}, journal = {mSphere}, volume = {8}, number = {2}, pages = {e0064822}, doi = {10.1128/msphere.00648-22}, pmid = {36942960}, issn = {2379-5042}, } @article {pmid36942200, year = {2023}, author = {Alharbi, MS and Alshehri, FA and Alobaidi, AS and Alrowis, R and Alshibani, N and Niazy, AA}, title = {High molecular weight hyaluronic acid reduces the growth and biofilm formation of the oral pathogen Porphyromonas gingivalis.}, journal = {The Saudi dental journal}, volume = {35}, number = {2}, pages = {141-146}, pmid = {36942200}, issn = {1013-9052}, abstract = {BACKGROUND: Porphyromonas gingivalis (P. gingivalis) is viewed as a keystone microorganism in the pathogenesis of periodontal and peri-implant diseases. Hyaluronic acid (HA) is believed to exert antimicrobial activity. The aim of this study is to assess the in-vitro growth and biofilm formation of P. gingivalis under HA and compare the effect of HA to that of azithromycin (AZM) and chlorhexidine (CHX).

MATERIALS AND METHODS: In each material, the minimum inhibitory concentration (MIC), 50% MIC, 25% MIC, and 12.5% MIC were tested. The growth of P. gingivalis was evaluated by absorbance spectrophotometry after 48 h. A biofilm inhibition assay was performed on a 72-hour culture by washing planktonic bacterial cells, fixing and staining adherent cells, and measuring the variation in stain concentrations relative to the untreated control using absorbance spectrophotometry.

RESULTS: The results show that the overall growth of P. gingivalis after 48 h was 0.048 ± 0.030, 0.008 ± 0.013, and 0.073 ± 0.071 under HA, AZM, and CHX, respectively, while the untreated control reached 0.236 ± 0.039. HA was also able to significantly reduce the biofilm formation of P. gingivalis by 64.30 % ± 22.39, while AZM and CHX reduced biofilm formation by 91.16 %±12.58 and 88.35 %±17.11, respectively.

CONCLUSIONS: High molecular-weight HA significantly inhibited the growth of P. gingivalis. The overall effect of HA on the growth of P. gingivalis was similar to that of CHX but less than that of AZM. HA was also able to significantly reduce the biofilm formation of P. gingivalis. However, the ability of HA to prevent the biofilm formation of P. gingivalis was generally less than that of both AZM and CHX.}, } @article {pmid36938129, year = {2022}, author = {Mohanta, YK and Chakrabartty, I and Mishra, AK and Chopra, H and Mahanta, S and Avula, SK and Patowary, K and Ahmed, R and Mishra, B and Mohanta, TK and Saravanan, M and Sharma, N}, title = {Nanotechnology in combating biofilm: A smart and promising therapeutic strategy.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1028086}, pmid = {36938129}, issn = {1664-302X}, abstract = {Since the birth of civilization, people have recognized that infectious microbes cause serious and often fatal diseases in humans. One of the most dangerous characteristics of microorganisms is their propensity to form biofilms. It is linked to the development of long-lasting infections and more severe illness. An obstacle to eliminating such intricate structures is their resistance to the drugs now utilized in clinical practice (biofilms). Finding new compounds with anti-biofilm effect is, thus, essential. Infections caused by bacterial biofilms are something that nanotechnology has lately shown promise in treating. More and more studies are being conducted to determine whether nanoparticles (NPs) are useful in the fight against bacterial infections. While there have been a small number of clinical trials, there have been several in vitro outcomes examining the effects of antimicrobial NPs. Nanotechnology provides secure delivery platforms for targeted treatments to combat the wide range of microbial infections caused by biofilms. The increase in pharmaceuticals' bioactive potential is one of the many ways in which nanotechnology has been applied to drug delivery. The current research details the utilization of several nanoparticles in the targeted medication delivery strategy for managing microbial biofilms, including metal and metal oxide nanoparticles, liposomes, micro-, and nanoemulsions, solid lipid nanoparticles, and polymeric nanoparticles. Our understanding of how these nanosystems aid in the fight against biofilms has been expanded through their use.}, } @article {pmid36937307, year = {2023}, author = {Zhu, X and Dou, F and Long, M and Wang, X and Liu, W and Li, F and Liu, T and Wu, Y}, title = {Electron shuttle-dependent biofilm formation and biocurrent generation: Concentration effects and mechanistic insights.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1070800}, pmid = {36937307}, issn = {1664-302X}, abstract = {INTRODUCTION: Electron shuttles (ESs) play a key role in extracellular electron transfer (EET) in Shewanella oneidensis MR-1. However, the quantification relationship between ES concentration, biofilm formation, and biocurrent generation has not been clarified.

METHODS: In this study, 9,10-anthraquinone-2-sulfonic acid (AQS)-mediated EET and biofilm formation were evaluated at different AQS concentrations in bioelectrochemical systems (BESs) with S. oneidensis MR-1.

RESULTS AND DISCUSSION: Both the biofilm biomass (9- to 17-fold) and biocurrent (21- to 80-fold) were substantially enhanced by exogenous AQS, suggesting the dual ability of AQS to promote both biofilm formation and electron shuttling. Nevertheless, biofilms barely grew without the addition of exogenous AQS, revealing that biofilm formation by S. oneidensis MR-1 is highly dependent on electron shuttling. The biofilm growth was delayed in a BES of 2,000 μM AQS, which is probably because the redundant AQS in the bulk solution acted as a soluble electron acceptor and delayed biofilm formation. In addition, the maximum biocurrent density in BESs with different concentrations of AQS was fitted to the Michaelis-Menten equation (R [2] = 0.97), demonstrating that microbial-catalyzed ES bio-reduction is the key limiting factor of the maximum biocurrent density in BESs. This study provided a fundamental understanding of ES-mediated EET, which could be beneficial for the enrichment of electroactive biofilms, the rapid start-up of microbial fuel cells (MFCs), and the design of BESs for wastewater treatment.}, } @article {pmid36937277, year = {2023}, author = {Xie, J and Zhang, H and Li, Y and Li, H and Pan, Y and Zhao, Y and Xie, Q}, title = {Transcriptome analysis of the biofilm formation mechanism of Vibrio parahaemolyticus under the sub-inhibitory concentrations of copper and carbenicillin.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1128166}, pmid = {36937277}, issn = {1664-302X}, abstract = {Biofilm formation of Vibrio parahaemolyticus enhanced its tolerance to the environment, but caused many serious problems to food safety and human health. In this paper, the effects of copper and carbenicillin (CARB) stress on the formation of the biofilms of V. parahaemolyticus organisms were studied, and RNA sequencing technology was used to compare the differences in transcriptome profiles of the biofilm-related genes of V. parahaemolyticus organisms under different sub-inhibitory stresses. The results proved that V. parahaemolyticus had a large growth difference under the two stresses, copper and CARB at 1/2 minimal inhibitory concentration (MIC), and it could form a stable biofilm under both stress conditions. The amount of biofilm formed under CARB stress was significantly higher than that of copper stress (p < 0.05). Based on the analysis of transcriptome sequencing results 323, 1,550, and 1,296 significantly differential expressed genes were identified in the three treatment groups namely 1/2 MIC CARB, Cu[2+], and Cu[2+]+CARB. Through COG annotation, KEGG metabolic pathway analysis and gene expression analysis related to biofilm formation, the functional pathways of transcriptome changes affecting V. parahaemolyticus were different in the three treatment groups, and the CARB treatment group was significantly different from the other two groups. These differences indicated that the ABC transport system, two-component system and quorum sensing were all involved in the biofilm formation of the V. parahaemolytic by regulating flagellar motility, extracellular polysaccharides and extracellular polymer synthesis. Exploring the effects of different stress conditions on the transcriptome of V. parahaemolyticus could provide a basis for future research on the complex network system that regulates the formation of bacterial biofilms.}, } @article {pmid36936302, year = {2023}, author = {Mao, T and Chai, B and Xiong, Y and Wang, H and Nie, L and Peng, R and Li, P and Yu, Z and Fang, F and Gong, X}, title = {In Vitro Inhibition of Growth, Biofilm Formation, and Persisters of Staphylococcus aureus by Pinaverium Bromide.}, journal = {ACS omega}, volume = {8}, number = {10}, pages = {9652-9661}, pmid = {36936302}, issn = {2470-1343}, abstract = {Biofilm or persister cells formed by Staphylococcus aureus are closely related to pathogenicity. However, no antimicrobials exist to inhibit biofilm formation or persister cells induced by S. aureus in clinical practice. This study found that pinaverium bromide had antibacterial activity against S. aureus, with the MIC50/MIC90 at 12.5/25 μM, respectively. Pinaverium bromide (at 4 × MIC) showed a rapid bactericidal effect on S. aureus planktonic cells, and it was more effective (at least 1-log10 cfu/mL) than linezolid, vancomycin, and ampicillin at 4 h of the time-killing test. Pinaverium bromide (at 10 × MIC) significantly inhibited the formation of S. aureus persister cells (at least 3-log10 cfu/mL) than linezolid, vancomycin, and ampicillin at 24, 48, 72, 96, and 120 h of the time-killing test. Biofilm formation and adherent cells of S. aureus isolates were significantly inhibited by pinaverium bromide (at 1/2 or 1/4 × MICs). The fluorescence intensity of the membrane polarity of S. aureus increased with the treatment of pinaverium bromide (≥1 × MIC), and the MICs of pinaverium bromide increased by 4 times with the addition of cell membrane phospholipids, phosphatidyl glycerol and cardiolipin. The cell viabilities of human hepatocellular carcinoma cells HepG2 and Huh7, mouse monocyte-macrophage cells J774, and human hepatic stellate cells LX-2 were slightly inhibited by pinaverium bromide (<50 μM). There were 54 different abundance proteins detected in the pinaverium bromide-treated S. aureus isolate by proteomics analysis, of which 33 proteins increased, whereas 21 proteins decreased. The abundance of superoxide dismutase sodM and ica locus proteins icaA and icaB decreased. While the abundance of global transcriptional regulator spxA and Gamma-hemolysin component B increased. In conclusion, pinaverium bromide had an antibacterial effect on S. aureus and significantly inhibited the formation of biofilm and persister cells of S. aureus.}, } @article {pmid36935141, year = {2023}, author = {Arismendi, D and Vera, I and Ahumada, I and Richter, P}, title = {A thin biofilm of chitosan as a sorptive phase in the rotating disk sorptive extraction of triclosan and methyl triclosan from water samples.}, journal = {Analytica chimica acta}, volume = {1252}, number = {}, pages = {341053}, doi = {10.1016/j.aca.2023.341053}, pmid = {36935141}, issn = {1873-4324}, mesh = {Animals ; *Triclosan/analysis ; *Chitosan ; Water ; *Water Pollutants, Chemical/analysis ; }, abstract = {The features and nature of the sorptive phase may be the stage that determines the scope of microextraction techniques. In search of new alternatives, materials of natural origin have recently been explored to establish greener analytical strategies. Based on that search, this research proposes the use of chitosan as a sorptive phase, which was assessed in the rotating disk sorptive extraction of emerging contaminants from aqueous systems. Chitosan is a biopolymer of animal origin that is usually found in the shells of crustaceans. The main characteristic of this material is the presence of a high number of nitrogenous groups, which gives it high reactivity, but its main disadvantage is associated with its high swelling capacity. In this research, chitosan was crosslinked with a low concentration of glutaraldehyde to form thin films that were easily immobilized on the surface of the rotating disk. The main advantage of this modification is the considerable decrease in the swelling capacity, which prevents loss and rupture of the sorbent during high rotation of the disk. In addition, it not only improved the physical characteristics of chitosan but also increased its extraction capacity. With regard to its use as a sorptive phase, all the variables associated with the microextraction of the analytes were studied, and optimal variables were found to be: pH 4, 20% NaCl (salting out effect), 30-45 min as equilibrium time and elution of analytes with a mixture of methanol:ethyl acetate (1:1). Validation of the methodology for the determination of methyl triclosan and triclosan was carried out, and relative recoveries between 89 and 96% and relative standard deviations less than 14% were found. The detection limits were 0.11 and 0.20 μg L[-1], respectively. Through its application in real samples (natural and residual waters), triclosan was quantified between 0.7 and 1.3 μg L[-1]. Finally, the "green" properties of the phase were evaluated, demonstrating that it is reusable for at least three cycles and biodegradable. Compared to its efficiency with a commercial phase (in this case, the styrene divinyl benzene phase), the proposed biosorbent provided a similar and even higher sorptive capacity (depending on the analyte).}, } @article {pmid36934281, year = {2023}, author = {Bayani, M and Raisolvaezin, K and Almasi-Hashiani, A and Mirhoseini, SH}, title = {Bacterial biofilm prevalence in dental unit waterlines: a systematic review and meta-analysis.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {158}, pmid = {36934281}, issn = {1472-6831}, mesh = {Humans ; *Dental Equipment/microbiology ; Prevalence ; *Bacteria ; Biofilms ; Equipment Contamination/prevention & control ; Colony Count, Microbial ; }, abstract = {BACKGROUNDS: Numerous studies have shown that dental unit water lines (DUWLs) are often contaminated by a wide range of micro-organisms (bacteria, fungi, protozoa) and various prevalence have been reported for it in previous studies. Therefore, this review study aims to describe the prevalence of bacterial biofilm contamination of DUWLs.

METHODS: This is a systematic review and meta-analysis in which the related keywords in different international databases, including Medline (via PubMed) and Scopus were searched. The retrieved studies were screened and the required data were extracted from the included studies. Three standard methods including American Dental Association (ADA), The Center for Disease Control and Prevention (CDC) and contaminated > 100 CFU/ml(C-100) standards were used to assess the bacterial biofilm contamination of DUWLs. All studies that calculated the prevalence of bacterial biofilm contamination of DUWLs, and English full-text studies were included in the meta-analysis. Studies that did not have relevant data or used unusual laboratory methods were excluded. Methodological risk of bias was assessed by a related checklist and finally, the data were pooled by fixed or random-effect models.

RESULTS: Seven hundred and thirty-six studies were identified and screened and 26 related studies were included in the meta-analysis. The oldest included study was published in 1976 and the most recent study was published in 2020. According to the ADA, CDC and C-100 standards, the prevalence of bacterial contamination was estimated to be 85.0% (95% confidence interval (CI): 66.0-94.0%), 77.0% (95%CI: 66.0-85.0%) and 69.0% (95%CI: 67.0-71.0%), respectively. The prevalence of Legionella Pneumophila and Pseudomonas Aeruginosa in DUWLs was estimated to be 12.0% (95%CI: 10.0-14.0%) and 8.0% (95%CI: 2.0-24.0%), respectively.

CONCLUSION: The results of this review study suggested a high prevalence of bacterial biofilm in DUWLs; therefore, the use of appropriate disinfecting protocol is recommended to reduce the prevalence of contamination and reduce the probable cross-infection.}, } @article {pmid36933573, year = {2023}, author = {Yang, J and Sim, YB and Moon Kim, S and Joo, HH and Jung, JH and Kim, SH}, title = {Enhanced continuous biohydrogen production using dynamic membrane with conductive biofilm supporter.}, journal = {Bioresource technology}, volume = {377}, number = {}, pages = {128900}, doi = {10.1016/j.biortech.2023.128900}, pmid = {36933573}, issn = {1873-2976}, mesh = {Fermentation ; *NAD/metabolism ; *Hydrogen/metabolism ; Bioreactors ; Biofilms ; }, abstract = {The present study investigated the effect of a conductive biofilm supporter on continuous production of biohydrogen in a dynamic membrane bioreactor (DMBR). Two lab-scale DMBRs were operated: one with a nonconductive polyester mesh (DMBR I) and the other with a conductive stainless-steel mesh (DMBR II). The highest average hydrogen productivity and the yield were 16.8% greater in DMBR II than in DMBR I, with values of 51.64 ± 0.66 L/L-d and 2.01 ± 0.03 mol H2/mol hexoseconsumed, respectively. The improved hydrogen production was concurrent with a higher NADH/NAD[+] ratio and a lower ORP (Oxidation-reduction potential). Metabolic flux analysis implied that the conductive supporter promoted H2-producing acetogenesis and repressed competitive NADH-consuming pathways, such as homoacetogenesis and lactate production. Microbial community analysis revealed that electroactive Clostridium sp. were the dominant H2 producers in DMBR II. Conclusively, conductive meshes may be useful as biofilm supporters of dynamic membranes during H2 production for selectively enhancing H2-producing pathways.}, } @article {pmid36933360, year = {2023}, author = {Wu, J and McAuliffe, O and O'Byrne, CP}, title = {Trehalose transport occurs via TreB in Listeria monocytogenes and it influences biofilm development and acid resistance.}, journal = {International journal of food microbiology}, volume = {394}, number = {}, pages = {110165}, doi = {10.1016/j.ijfoodmicro.2023.110165}, pmid = {36933360}, issn = {1879-3460}, mesh = {*Listeria monocytogenes ; Trehalose/metabolism ; Bacterial Proteins/genetics/metabolism ; Carbohydrates ; Membrane Transport Proteins ; Biofilms ; }, abstract = {Listeria monocytogenes is a pathogenic bacterium that can inhabit a diverse range of environmental niches. This is largely attributed to the high proportion of carbohydrate-specific phosphotransferase system (PTS) genes in its genome. Carbohydrates can be assimilated as sources of energy but additionally they can serve as niche-specific cues for L. monocytogenes to shape its global gene expression, in order to cope with anticipated stresses. To examine carbon source utilization among wild L. monocytogenes isolates and to understand underlying molecular mechanisms, a diverse collection of L. monocytogenes strains (n = 168) with whole genome sequence (WGS) data available was screened for the ability to grow in chemically defined media with different carbon sources. The majority of the strains grew in glucose, mannose, fructose, cellobiose, glycerol, trehalose, and sucrose. Maltose, lactose, and rhamnose supported slower growth while ribose did not support any growth. In contrast to other strains, strain1386, which belonged to clonal complex 5 (CC5), was unable to grow on trehalose as a sole carbon source. WGS data revealed that it carried a substitution (N352K) in a putative PTS EIIBC trehalose transporter, TreB, while this asparagine residue is conserved in other strains in this collection. Spontaneous mutants of strain 1386 that could grow in trehalose were found to harbour a reversion of the substitution in TreB. These results provide genetic evidence that TreB is responsible for trehalose uptake and that the N352 residue is essential for TreB activity. Moreover, reversion mutants also restored other unusual phenotypes that strain 1386 displayed, i.e. altered colony morphology, impaired biofilm development, and reduced acid resistance. Transcriptional analysis at stationary phase with buffered BHI media revealed that trehalose metabolism positively influences the transcription of genes encoding amino acid-based acid resistance mechanisms. In summary, our results demonstrated that N352 is key to the function of the sole trehalose transporter TreB in L. monocytogenes and suggest that trehalose metabolism alters physiology to favour biofilm development and acid stress resistance. Moreover, since strain 1386 is among the strains recommended by the European Union Reference Laboratory for conducting food challenge studies in order to determine whether or not L. monocytogenes can grow in food, these findings have important implications for food safety.}, } @article {pmid36933236, year = {2023}, author = {Chen, Q and Qi, M and Shi, F and Liu, C and Shi, Y and Sun, Y and Bai, X and Wang, L and Sun, X and Dong, B and Li, C}, title = {Novel Twin-Crystal Nanosheets with MnO2 Modification to Combat Bacterial Biofilm against Periodontal Infections via Multipattern Strategies.}, journal = {Advanced healthcare materials}, volume = {}, number = {}, pages = {e2300313}, doi = {10.1002/adhm.202300313}, pmid = {36933236}, issn = {2192-2659}, support = {82170998//National Science Foundation of China/ ; 52250007//National Science Foundation of China/ ; 62205122//National Science Foundation of China/ ; 20220204128YY//Key Program of Natural Science Foundation of Jilin Province/ ; 20220402005GH//Key Program of Natural Science Foundation of Jilin Province/ ; 2022C044-1//Funding of Jilin Province Development and Reform Commission/ ; 2021C035-1//Funding of Jilin Province Development and Reform Commission/ ; JCSZ2021893-15//Science and Technology Project of Jilin Province Financial Department/ ; 20220203145SF//Key Research and Development Program of Science and Technology Development Project of Jilin Province/ ; 20210203087SF//Key Research and Development Program of Science and Technology Development Project of Jilin Province/ ; 2022JC076//Health Department Research Projects of Jilin Province/ ; //Fundamental Research Funds for the Central Universities/ ; }, abstract = {Nowadays the multifunctional approaches to kill oral bacteria based on various nanocomposites have made great progress against periodontal infections, while the material structure and its functional integration are still insufficient. Herein, this work proposes a therapeutic strategy of chemodynamical therapy (CDT) and photothermal therapy (PTT) in monocrystals to effectively enhance the synergistic treatment. The CuS/MnS@MnO2 consisting of hexagonal CuS/MnS nano-twin-crystal with a shell layer of MnO2 is developed. In this nanosystem, the purpose of synergistic treatment of periodontitis by combining PTT/CDT is achieved within a CuS/MnS monocrystal, where CuS serves to achieve photothermal conversion, dissipate the biofilm and transfer the heat in situ to the integrated MnS, thus promoting the Mn[2+] -mediated CDT process. Meanwhile, the CDT process can generate the highly toxic hydroxyl radical to destroy extracellular DNA by utilization of endogenous H2 O2 produced by Streptococci in the oral biofilm, cooperating with PTT to dissipate the bacterial biofilm. With the design of the outer shell of MnO2 , the selective bacteria-killing can be realized by producing oxygen which can protect the periodontal non-pathogenic aerobic bacteria and threaten the survival of anaerobic pathogens. Therefore, such design via multipattern strategies to combat microorganisms would provide a bright prospect for the clinical treatment of bacterial infections.}, } @article {pmid36931368, year = {2023}, author = {Sindelo, A and Sen, P and Nyokong, T}, title = {Photoantimicrobial activity of Schiff-base morpholino phthalocyanines against drug resistant micro-organisms in their planktonic and biofilm forms.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {42}, number = {}, pages = {103519}, doi = {10.1016/j.pdpdt.2023.103519}, pmid = {36931368}, issn = {1873-1597}, abstract = {Antimicrobial photodynamic inactivation (aPDI) is a treatment for the eradication of drug-resistant micro-organisms. One of the advantages of this technique, is that there is minimal possibility of microbial resistance. Hence, herein, the preparation and characterization of novel neutral and cationic morpholine containing Schiff base phthalocyanines are reported. The cationic complexes gave moderate singlet oxygen quantum yields (ΦΔ) of ∼0.2 in aqueous media. Conversely, the neutral complexes generated very low ΦΔ values making them very poor candidates for antimicrobial studies. The cationic phthalocyanines showed excellent photodynamic activity against planktonic cells of all micro-organisms (Candida albicans, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella enterica subspecies enterica serovar Choleraesuis, vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus). The efficiency of aPDI was shown to be both concentration and light-dose-dependent. Mono biofilms were susceptible when treated with 200 µM of cationic Pcs at 108 J/cm[2]. However, ∼10% of the mixed biofilm survived after treatment.}, } @article {pmid36930448, year = {2023}, author = {Yazıcı, BC and Bakhedda, N and Akçelik, N}, title = {Effect of nisin and p-coumaric acid on autoinducer-2 activity, biofilm formation, and sprE expression of Enterococcus faecalis.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {2}, pages = {601-608}, pmid = {36930448}, issn = {1678-4405}, support = {118Z697//TUBITAK/ ; }, mesh = {*Enterococcus faecalis ; *Biofilms ; Quorum Sensing ; Coumaric Acids/pharmacology ; Bacterial Proteins/metabolism ; }, abstract = {Quorum sensing (QS) is an inter- and intracellular communication mechanism that regulates gene expression in response to population size. Autoinducer-2 (AI-2) signaling is a QS signaling molecule common to both Gram-negative and Gram-positive bacteria. Enterococcus faecalis is one of the leading causes of nosocomial infections worldwide. There has been an increasing interest in controlling infectious diseases through targeting the QS mechanism using natural compounds. This study aimed to investigate the effect of nisin and p-coumaric acid (pCA), on biofilm formation and AI-2 signaling in E. faecalis. Their effect on the expression of the QS-regulated virulence encoding gene sprE was also investigated. Nisin exhibited a MIC ranging from 0.25 to 0.5 mg/mL, while the MIC of pCA was 1 mg/mL. The luminescence-based response of the reporter strain Vibrio harveyi BB170 was used to determine AI-2 activity in E. faecalis strains. Nisin was not effective in inhibiting AI-2 activity, while pCA reduced AI-2 activity by ≥ 60%. Moreover, pCA and nisin combination showed higher inhibitory effect on biofilm formation of E. faecalis, compared to the treatment of pCA or nisin alone. qRT-PCR analysis showed that nisin alone and the combination of nisin and pCA, at their MIC values, led to a 32.78- and 40.22-fold decrease in sprE gene expression, respectively, while pCA alone did not have a significant effect. Considering the demand to explore new therapeutic avenues for infectious bacteria, this study was the first to report that pCA can act like a quorum sensing inhibitor (QSI) against AI-2 signaling in E. faecalis.}, } @article {pmid36930446, year = {2023}, author = {Baghiat Esfahani, M and Khodavandi, A and Alizadeh, F and Bahador, N}, title = {Biofilm-associated genes as potential molecular targets of nano-Fe3O4 in Candida albicans.}, journal = {Pharmacological reports : PR}, volume = {75}, number = {3}, pages = {682-694}, pmid = {36930446}, issn = {2299-5684}, mesh = {*Candida albicans/genetics ; *Biofilms ; Biological Assay ; Down-Regulation ; Gentian Violet ; }, abstract = {BACKGROUND: There are few effective treatments for Candida biofilm-associated infections. The present study demonstrated changes in the expression of biofilm-associated genes in Candida albicans treated with magnetic iron oxide nanoparticles (denoted as nano-Fe3O4).

METHODS: Nano-Fe3O4 was biologically synthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. Additionally, the biologically synthesized nano-Fe3O4 was characterized by visual observation; ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. The biologically synthesized nano-Fe3O4 was tested for growth and biofilm formation in C. albicans. Furthermore, quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to study the inhibition of biofilm-associated genes in C. albicans treated with nano-Fe3O4.

RESULTS: The production of biologically synthesized nano-Fe3O4 was confirmed using extensive characterization methods. The nano-Fe3O4 inhibited growth and biofilm formation. Nano-Fe3O4 exhibited growth inhibition with minimum inhibition concentrations (MICs) of 50 to 200 μg mL[-1]. The anti-biofilm effects of nano-Fe3O4 were shown by 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay, crystal violet staining, and light field microscopy. The gene expression results showed that the downregulation of BCR1, ALS1, ALS3, HWP1, and ECE1 genes inhibited the biofilm formation in C. albicans. ALS1 reduction was greater than others, with downregulation of 1375.83-, 1178.71-, and 768.47-fold at 2 × MIC, 1 × MIC, and ½ × MIC of nano-Fe3O4, respectively.

CONCLUSION: Biofilm-associated genes as potential molecular targets of nano-Fe3O4 in C. albicans may be an effective novel treatment strategy for biofilm-associated infections.}, } @article {pmid36929684, year = {2023}, author = {Du, X and Ma, M and Zhang, Y and Yu, X and Chen, L and Zhang, H and Meng, Z and Jia, X and Chen, J and Meng, Q and Li, C}, title = {Synthesis of Cationic Biphen[4, 5]arenes as Biofilm Disruptors.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {62}, number = {21}, pages = {e202301857}, doi = {10.1002/anie.202301857}, pmid = {36929684}, issn = {1521-3773}, mesh = {Mice ; Animals ; *Staphylococcus aureus ; *Escherichia coli ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cefazolin ; Microbial Sensitivity Tests ; }, abstract = {Since bacteria in biofilms are inherently resistant to antibiotics and biofilm-associated infections pose a serious threat to global public health, new therapeutic agents and schemes are urgently needed to meet clinical requirements. Here two quaternary ammonium-functionalized biphen[n]arenes (WBPn, n=4, 5) were designed and synthesized with excellent anti-biofilm potency. Not only could they inhibit the assembly of biofilms, but also eradicate intractable mature biofilms formed by Gram-positive S. aureus and Gram-negative E. coli bacterial strains. Moreover, they could strongly complex a conventional antibiotic, cefazolin sodium (CFZ) with complex stability constants of (7.41±0.29)×10[4] M[-1] for CFZ/WBP4 and (4.98±0.49)×10[3] M[-1] for CFZ/WBP5. Combination of CFZ by WBP4 and WBP5 synergistically enhanced biofilm eradication performance in vitro and statistically improved healing efficacy on E. coli-infected mice models, providing a novel supramolecular strategy for combating biofilm-associated infections.}, } @article {pmid36929159, year = {2023}, author = {Kobayashi, A and Nakamura, M and Tsujii, M and Makino, K and Nagayama, T and Nakamura, K and Nanatani, K and Kota, K and Furuuchi, Y and Kayamori, S and Furuta, T and Suzuki, I and Hayakawa, Y and Tanudjaja, E and Ishimaru, Y and Uozumi, N}, title = {Two cyanobacterial response regulators with diguanylate cyclase activity, Rre2 and Rre8, participate in biofilm formation.}, journal = {Molecular microbiology}, volume = {119}, number = {5}, pages = {599-611}, doi = {10.1111/mmi.15057}, pmid = {36929159}, issn = {1365-2958}, mesh = {*Escherichia coli Proteins/genetics/metabolism ; Phosphorus-Oxygen Lyases/genetics/metabolism ; Biofilms ; *Synechocystis/genetics/metabolism ; Cyclic GMP/metabolism ; Bacterial Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Phototrophic bacteria face diurnal variations of environmental conditions such as light and osmolarity that affect their carbon metabolism and ability to generate organic compounds. The model cyanobacterium, Synechocystis sp. PCC 6803 forms a biofilm when it encounters extreme conditions like high salt stress, but the molecular mechanisms involved in perception of environmental changes that lead to biofilm formation are unknown. Here, we studied two two-component regulatory systems (TCSs) that contain diguanylate cyclases (DGCs), which produce the second messenger c-di-GMP, as potential components of the biofilm-inducing signaling pathway in Synechocystis. Analysis of single mutants provided evidence for involvement of the response regulators, Rre2 and Rre8 in biofilm formation. A bacterial two-hybrid assay showed that Rre2 and Rre8 each formed a TCS with a specific histidine kinase, Hik12 and Hik14, respectively. The in vitro assay showed that Rre2 had DGC activity regardless of its de/phosphorylation status, whereas Rre8 required phosphorylation for DGC activity. Hik14-Rre8 likely functioned as an inducible sensing system in response to environmental change. Biofilm assays with Synechocystis mutants suggested that pairs of hik12-rre2 and hik14-rre8 responded to high salinity-induced biofilm formation. Inactivation of hik12-rre2 and hik14-rre8 did not affect the performance of the light reactions of photosynthesis. These data suggest that Hik12-Rre2 and Hik14-Rre8 participate in biofilm formation in Synechocystis by regulating c-di-GMP production via the DGC activity of Rre2 and Rre8.}, } @article {pmid36928367, year = {2023}, author = {El-Naggar, NE and Dalal, SR and Zweil, AM and Eltarahony, M}, title = {Artificial intelligence-based optimization for chitosan nanoparticles biosynthesis, characterization and in‑vitro assessment of its anti-biofilm potentiality.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {4401}, pmid = {36928367}, issn = {2045-2322}, mesh = {Humans ; *Chitosan/chemistry ; Artificial Intelligence ; Staphylococcus aureus ; *COVID-19 ; *Nanoparticles/chemistry ; *Anti-Infective Agents/pharmacology ; }, abstract = {Chitosan nanoparticles (CNPs) are promising biopolymeric nanoparticles with excellent physicochemical, antimicrobial, and biological properties. CNPs have a wide range of applications due to their unique characteristics, including plant growth promotion and protection, drug delivery, antimicrobials, and encapsulation. The current study describes an alternative, biologically-based strategy for CNPs biosynthesis using Olea europaea leaves extract. Face centered central composite design (FCCCD), with 50 experiments was used for optimization of CNPs biosynthesis. The artificial neural network (ANN) was employed for analyzing, validating, and predicting CNPs biosynthesis using Olea europaea leaves extract. Using the desirability function, the optimum conditions for maximum CNPs biosynthesis were determined theoretically and verified experimentally. The highest experimental yield of CNPs (21.15 mg CNPs/mL) was obtained using chitosan solution of 1%, leaves extract solution of 100%, initial pH 4.47, and incubation time of 60 min at 53.83°C. The SEM and TEM images revealed that CNPs had a spherical form and varied in size between 6.91 and 11.14 nm. X-ray diffraction demonstrates the crystalline nature of CNPs. The surface of the CNPs is positively charged, having a Zeta potential of 33.1 mV. FTIR analysis revealed various functional groups including C-H, C-O, CONH2, NH2, C-OH and C-O-C. The thermogravimetric investigation indicated that CNPs are thermally stable. The CNPs were able to suppress biofilm formation by P. aeruginosa, S. aureus and C. albicans at concentrations ranging from 10 to 1500 µg/mL in a dose-dependent manner. Inhibition of biofilm formation was associated with suppression of metabolic activity, protein/exopolysaccharide moieties, and hydrophobicity of biofilm encased cells (r ˃ 0.9, P = 0.00). Due to their small size, in the range of 6.91 to 11.14 nm, CNPs produced using Olea europaea leaves extract are promising for applications in the medical and pharmaceutical industries, in addition to their potential application in controlling multidrug-resistant microorganisms, especially those associated with post COVID-19 pneumonia in immunosuppressed patients.}, } @article {pmid36926839, year = {2023}, author = {Bird, LJ and Leary, DH and Hervey, J and Compton, J and Phillips, D and Tender, LM and Voigt, CA and Glaven, SM}, title = {Marine Biofilm Engineered to Produce Current in Response to Small Molecules.}, journal = {ACS synthetic biology}, volume = {12}, number = {4}, pages = {1007-1020}, doi = {10.1021/acssynbio.2c00417}, pmid = {36926839}, issn = {2161-5063}, mesh = {Electron Transport ; *Biofilms ; Genetic Engineering ; *Shewanella/genetics/metabolism ; }, abstract = {Engineered electroactive bacteria have potential applications ranging from sensing to biosynthesis. In order to advance the use of engineered electroactive bacteria, it is important to demonstrate functional expression of electron transfer modules in chassis adapted to operationally relevant conditions, such as non-freshwater environments. Here, we use the Shewanella oneidensis electron transfer pathway to induce current production in a marine bacterium, Marinobacter atlanticus, during biofilm growth in artificial seawater. Genetically encoded sensors optimized for use in Escherichia coli were used to control protein expression in planktonic and biofilm attached cells. Significant current production required the addition of menaquinone, which M. atlanticus does not produce, for electron transfer from the inner membrane to the expressed electron transfer pathway. Current through the S. oneidensis pathway in M. atlanticus was observed when inducing molecules were present during biofilm formation. Electron transfer was also reversible, indicating that electron transfer into M. atlanticus could be controlled. These results show that an operationally relevant marine bacterium can be genetically engineered for environmental sensing and response using an electrical signal.}, } @article {pmid36926823, year = {2023}, author = {Estes Bright, LM and Garren, MRS and Douglass, M and Handa, H}, title = {Synthesis and Characterization of Nitric Oxide-Releasing Ampicillin as a Potential Strategy for Combatting Bacterial Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {15}, number = {12}, pages = {15185-15194}, pmid = {36926823}, issn = {1944-8252}, mesh = {*Nitric Oxide/chemistry ; *Methicillin-Resistant Staphylococcus aureus ; S-Nitroso-N-Acetylpenicillamine/pharmacology/chemistry ; Anti-Bacterial Agents/pharmacology ; Ampicillin/pharmacology ; Bacteria ; Biofilms ; }, abstract = {Biofilm formation on biomaterial interfaces and the development of antibiotic-resistant bacteria have decreased the effectiveness of traditional antibiotic treatment of infections. In this project, ampicillin, a commonly used antibiotic, was conjugated with S-nitroso-N-acetylpenicillamine (SNAP), an S-nitrosothiol compound (RSNO) used for controlled nitric oxide (NO) release. This novel multifunctional molecule is the first of its kind to provide combined antibiotic and NO treatment of infectious pathogens. Characterization of the molecule included NMR, FTIR, and mass spectrometry. NO release behavior was also measured and compared to pure, unmodified SNAP. When evaluating the antimicrobial efficacy, the synthesized SNAPicillin molecule showed the lowest MIC value against Gram-negative Pseudomonas aeruginosa and Gram-positive methicillin-resistant Staphylococcus aureus compared to ampicillin and SNAP alone. SNAPicillin also displayed enhanced biofilm dispersal and killing of both bacterial strains when treating a 48 h biofilm preformed on a polymer surface. The antibacterial results combined with the biocompatibility of the molecule show great promise for infection prevention and treatment of polymeric interfaces to reduce medical device-related infections.}, } @article {pmid36926513, year = {2023}, author = {Varma, A and Warghane, A and Dhiman, NK and Paserkar, N and Upadhye, V and Modi, A and Saini, R}, title = {The role of nanocomposites against biofilm infections in humans.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1104615}, pmid = {36926513}, issn = {2235-2988}, mesh = {Humans ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Nanocomposites ; *Bacterial Infections ; *Nanoparticles ; Bacteria ; }, abstract = {The use of nanomaterials in several fields of science has undergone a revolution in the last few decades. It has been reported by the National Institutes of Health (NIH) that 65% and 80% of infections are accountable for at least 65% of human bacterial infections. One of their important applications in healthcare is the use of nanoparticles (NPs) to eradicate free-floating bacteria and those that form biofilms. A nanocomposite (NC) is a multiphase stable fabric with one or three dimensions that are much smaller than 100 nm, or systems with nanoscale repeat distances between the unique phases that make up the material. Using NC materials to get rid of germs is a more sophisticated and effective technique to destroy bacterial biofilms. These biofilms are refractory to standard antibiotics, mainly to chronic infections and non-healing wounds. Materials like graphene and chitosan can be utilized to make several forms of NCs, in addition to different metal oxides. The ability of NCs to address the issue of bacterial resistance is its main advantage over antibiotics. This review highlights the synthesis, characterization, and mechanism through which NCs disrupt Gram-positive and Gram-negative bacterial biofilms, and their relative benefits and drawbacks. There is an urgent need to develop materials like NCs with a larger spectrum of action due to the rising prevalence of human bacterial diseases that are multidrug-resistant and form biofilms.}, } @article {pmid36924752, year = {2023}, author = {Sterniša, M and Gradišar Centa, U and Drnovšek, A and Remškar, M and Smole Možina, S}, title = {Pseudomonas fragi biofilm on stainless steel (at low temperatures) affects the survival of Campylobacter jejuni and Listeria monocytogenes and their control by a polymer molybdenum oxide nanocomposite coating.}, journal = {International journal of food microbiology}, volume = {394}, number = {}, pages = {110159}, doi = {10.1016/j.ijfoodmicro.2023.110159}, pmid = {36924752}, issn = {1879-3460}, mesh = {Animals ; *Pseudomonas fragi ; *Listeria monocytogenes ; Stainless Steel/analysis ; *Campylobacter jejuni ; Temperature ; Extracellular Polymeric Substance Matrix/chemistry ; Biofilms ; Pseudomonas ; Food Microbiology ; Bacterial Adhesion ; Colony Count, Microbial ; }, abstract = {Pseudomonas spp. are widely distributed bacteria on surfaces in the food production and processing environment, where they form extracellular polymeric substance rich biofilms that interact with other bacteria. In this study, the influence of biofilm of Pseudomonas fragi ATCC 4973 on Listeria monocytogenes ATCC 19115 and Campylobacter jejuni NCTC 11168 was investigated at 5 °C and 15 °C on stainless steel in broth and food homogenates (fish or chicken meat). Stainless steel was then coated with PVDF-HFP/PVP/MoO3 nanocomposite and examined for surface changes (scanning electron microscope, static contact angle, Vickers hardness and elastic modulus). The effect of the prepared nanocomposite coating on P. fragi and on L. monocytogenes and C. jejuni was evaluated in mono- and co-culture. P. fragi produced more biofilm at 15 °C than at 5 °C, especially when food homogenates were used as growth media. Co-cultivation with pathogens did not affect biofilm production by P. fragi, but significant changes were observed in L. monocytogenes and C. jejuni, resulting in a decrease and increase, respectively, in the determined number of culturable biofilm cells. The first change was probably due to competition for the surface, and the second to the oxygen gradient. Stainless steel was then coated with a PVDF-HFP/PVP/MoO3 nanocomposite, which was characterised by lower roughness and higher wettability, but lower hardness compared to uncoated stainless steel. The prepared nanocoating showed bactericidal activity when tested in phosphate buffered saline. When used in food homogenates, a reduction of over 95 % in bacterial counts was observed. An abundant biofilm of P. fragi proved protective to L. monocytogenes and C. jejuni against the functionalised nanocomposite surface when tested in food homogenates. The control of spoilage Pseudomonas spp., which are common in the food production and processing environment, is important for reducing the contamination of food with spoilage bacteria and with pathogens such as L. monocytogenes and C. jejuni, which may be present in the same environment. The PVDF-HFP/PVP/MoO3 nanocomposite showed good potential for use as a coating for food contact surfaces, but possible migration of nanoparticles from the nanocomposite coating to food should be evaluated before its commercial use.}, } @article {pmid36922940, year = {2023}, author = {Diaz, A and Dixit, AR and Khodadad, CL and Hummerick, ME and Justiano-Velez, YA and Li, W and O'Rourke, A}, title = {Biofilm formation is correlated with low nutrient and simulated microgravity conditions in a Burkholderia isolate from the ISS water processor assembly.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100110}, pmid = {36922940}, issn = {2590-2075}, abstract = {The International Space Station (ISS) Water Processor Assembly (WPA) experiences intermittent dormancy in the WPA wastewater tank during water recycling events which promotes biofilm formation within the system. In this work we aimed to gain a deeper understanding of the impact of nutrient limitation on bacterial growth and biofilm formation under microgravity in support of biofilm mitigation efforts in exploration water recovery systems. A representative species of bacteria that is commonly cultured from the ISS WPA was cultured in an WPA influent water ersatz formulation tailored for microbiological studies. An isolate of Burkholderia contaminans was cultured under a simulated microgravity (SμG) treatment in a vertically rotating high-aspect rotating vessel (HARV) to create the low shear modeled microgravity (LSMMG) environment on a rotating wall vessel (RWV), with a rotating control (R) in the horizontal plane at the predetermined optimal rotation per minute (rpm) speed of 20. Over the course of the growth curve, the bacterial culture in ersatz media was harvested for bacterial counts, and transcriptomic and nutrient content analyses. The cultures under SμG treatment showed a transcriptomic signature indicative of nutrient stress and biofilm formation as compared to the R control treatment. Further analysis of the WPA ersatz over the course of the growth curve suggests that the essential nutrients of the media were consumed faster in the early stages of growth for the SμG treatment and thus approached a nutrient limited growth condition earlier than in the R control culture. The observed limited nutrient response may serve as one element to explain a moderate enhancement of adherent biofilm formation in the SμG treatment after 24 h. While nutrients levels can be modulated, one implication of this investigation is that biofilm mitigation in the ISS environment could benefit from methods such as mixing or the maintenance of minimum flow within a dormant water system in order to force convection and offset the response of microbes to the secondary effects of microgravity.}, } @article {pmid36922440, year = {2023}, author = {Ji, C and Wang, H and Cui, H and Zhang, C and Li, R and Liu, T}, title = {Characterization and evaluation of substratum material selection for microalgal biofilm cultivation.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {7-8}, pages = {2707-2721}, pmid = {36922440}, issn = {1432-0614}, mesh = {*Microalgae ; Biofilms ; Biomass ; Hydrophobic and Hydrophilic Interactions ; *Scenedesmus ; }, abstract = {Biofilm cultivation is considered a promising method to achieve higher microalgae biomass productivity with less water consumption and easier harvest compared to conventional suspended cultivation. However, studies focusing on the selection of substratum material and optimization of the growth of certain microalgae species on specific substratum are limited. This study investigated the selection of membranous and fabric fiber substrata for the attachment of unicellular microalgae Scenedesmus dimorphus and filamentous microalgae Tribonema minus in biofilm cultivation. The results indicated that both algal species preferred hydrophilic membranous substrata and nitrate cellulose/cellulose acetate membrane (CN-CA) was selected as a suitable candidate on which the obtained biomass yields were up to 10.24 and 7.81 g m[-2] day[-1] for S. dimorphus and T. minus, respectively. Furthermore, high-thread cotton fiber (HCF) and low-thread polyester fiber (LPEF) were verified as the potential fabric fiber substrata for S. dimorphus (5.42 g m[-2] day[-1]) and T. minus (5.49 g m[-2] day[-1]) attachment, respectively. The regrowth of microalgae biofilm cultivation strategy was applied to optimize the algae growth on the fabric fiber substrata, with higher biomass density and shear resistibility achieved for both algal species. The present data highlight the importance to establish the standards for selection the suitable substratum materials in ensuring the high efficiency and sustainability of the attached microalgal biomass production. KEY POINTS: • CN-CA was suitable membranous substratum candidate for algal biofilm cultivation. • HCF and LPEF were potential fabric fiber substrata for S. dimorphus and T. minus. • Regrowth biofilm cultivation was effective in improving algal biomass and attachment.}, } @article {pmid36921788, year = {2023}, author = {Yadav, S and Tripathi, S and Purchase, D and Chandra, R}, title = {Development of a biofilm-forming bacterial consortium and quorum sensing molecules for the degradation of lignin-containing organic pollutants.}, journal = {Environmental research}, volume = {226}, number = {}, pages = {115618}, doi = {10.1016/j.envres.2023.115618}, pmid = {36921788}, issn = {1096-0953}, mesh = {*Quorum Sensing ; *Environmental Pollutants ; Lignin ; RNA, Ribosomal, 16S ; Biofilms ; Bacteria/genetics/metabolism ; }, abstract = {The presence of lignin along with other pollutants makes effluent more complex when it is discharged from Pulp and paper mills. The present study investigates the use of biofilm-forming bacteria isolated from pulp paper mill effluent contaminated sites (PPMECSs) for lignin degradation. Isolated biofilm-forming and lignin-degrading bacteria were identified as Bacillus subtilis, Enterobacter cancerogenus, and Bacillus licheniformis by 16S rRNA gene sequencing. Thin liquid chromatography (TLC) analysis showed that the consortium of bacteria produced acyl-homoserine lactone (AHL) as quorum sensing molecules and extracellular polymeric substances (EPS) that protect the bacterial consortium under unfavorable conditions. The potential consortium was able to reduce lignin (900 ppm) by 73% after 8 days of incubation in a minimal salt medium containing kraft lignin and glucose at pH 7.0 and 37 °C as compared to individual strains. The degradation by-products were identified as amides, alcohols, and acids. The major organic pollutants in the effluent were reduced after treatment of the constructed consortium, thus confirming active biotransformation and biodegradation of the lignin. Microscopic examination also indicated the presence of lignin induced biofilm formation. Hence, the constructed biofilm-forming bacterial consortia based on quorum sensing offered a sustainable and effective solution to treat lignin-containing complex pollutants.}, } @article {pmid36921636, year = {2023}, author = {Yang, L and Pang, S and Zhou, J and Li, X and Yao, M and Xia, S}, title = {Biological reduction and hydrodechlorination of chlorinated nitroaromatic antibiotic chloramphenicol under H2-transfer membrane biofilm reactor.}, journal = {Bioresource technology}, volume = {376}, number = {}, pages = {128881}, doi = {10.1016/j.biortech.2023.128881}, pmid = {36921636}, issn = {1873-2976}, mesh = {*Anti-Bacterial Agents ; *Chloramphenicol ; 4-Aminobenzoic Acid ; Bioreactors ; Nitrates/metabolism ; Biofilms ; Denitrification ; }, abstract = {Chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a persistent pollutant that is widely present in environments. A H2 transfer membrane biofilm reactor (H2-MBfR) and short-term batch tests were setup to investigate the co-removal of CAP and NO3[-]. Results showed that the presence of CAP (<10 mg L[-1]) has no effect on the denitrification process while 100% removal efficiency of CAP can be obtained when nitrate was absent. Nitroaromatic reduction and completely dechlorination were successfully realized when CAP was removed. The CAP transformation product p-aminobenzoic acid (PABA) was detected and batch tests revealed that the hydroxy carboxylation was far faster than nitroaromatic reduction when p-nitrobenzyl alcohol (PNBOH) was conversed to p-aminobenzoic acid (PABA). The path way of CAP degradation was proposed based on the intermediate's analysis. Microbial community analysis indicated that Pleomorphomonadaceae accounts for the dechlorination of CAP.}, } @article {pmid36921483, year = {2023}, author = {Zeng, X and Mo, Z and Zheng, J and Wei, C and Dai, Y and Yan, Y and Qiu, S}, title = {Effects of biofilm and co-culture with Bacillus velezensis on the synthesis of esters in the strong flavor Baijiu.}, journal = {International journal of food microbiology}, volume = {394}, number = {}, pages = {110166}, doi = {10.1016/j.ijfoodmicro.2023.110166}, pmid = {36921483}, issn = {1879-3460}, mesh = {*Esters ; Coculture Techniques ; *Bacillus ; Bacteria ; Biofilms ; Saccharomyces cerevisiae ; }, abstract = {Biofilm plays an important role in resisting the adverse environment, improving the taste and texture, and promoting the synthesis of flavor substances. However, to date, the findings on the effect of biofilm and dominating bacteria Bacillus on the ester synthesis in the Baijiu field have been largely lacked. Therefore, the objectives of the present study were to primarily isolate biofilm-producing microbes in the fermented grains, evaluate the stress tolerance capacity, and unveil the effect of biofilm and co-culture with Bacillus on the ester synthesis in the strong flavor Baijiu. Results indicated that after isolation and evaluation of stress-tolerance capacity, bacterial strain BG-5 and yeast strains YM-21 and YL-10 were demonstrated as mediate or strong biofilm-producing microbes and were identified as Bacillus velezensis, Saccharomycopsis fibuligera, and Zygosaccharomyces bailii, respectively. Solid phase microextraction/gas chromatography-mass spectrometer indicated that biofilm could enhance the diversity of esters while reduce the contents of ester. The scanning electron microscopy showed an inhibitory effect of B. velezensis on the growth of S. fibuligera, further restraining the production of esters. Taken together, both biofilm and B. velezensis influence the ester synthesis process. The present study is the first to reveal the biofilm-producing microorganisms in fermented grains and to preliminarily investigate the effect of biofilm on the ester synthesis in the Baijiu field.}, } @article {pmid36920192, year = {2023}, author = {Al-Shamiri, MM and Wang, J and Zhang, S and Li, P and Odhiambo, WO and Chen, Y and Han, B and Yang, E and Xun, M and Han, L and Han, S}, title = {Probiotic Lactobacillus Species and Their Biosurfactants Eliminate Acinetobacter baumannii Biofilm in Various Manners.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0461422}, pmid = {36920192}, issn = {2165-0497}, abstract = {Acinetobacter baumannii is a critical biofilm-forming pathogen that has presented great challenges in the clinic due to multidrug resistance. Thus, new methods of intervention are needed to control biofilm-associated infections. In this study, among three tested Lactobacillus species, Lactobacillus rhamnosus showed significant antimaturation and antiadherence effects against A. baumannii biofilm. Lactic acid (LA) and acetic acid (AA) were the most effective antibiofilm biosurfactants (BSs) produced by L. rhamnosus. This antibiofilm phenomenon produced by LA and AA was due to the strong bactericidal effect, which worked from very early time points, as determined by colony enumeration and confocal laser scanning microscope. The cell destruction of A. baumannii appeared in both the cell envelope and cytoplasm. A discontinuous cell envelope, the leakage of cell contents, and the increased extracellular activity of ATPase demonstrated the disruption of the cell membrane by LA and AA. These effects also demonstrated the occurrence of protein lysis. In addition, bacterial DNA interacted with and was damaged by LA and AA, resulting in significantly reduced expression of biofilm and DNA repair genes. The results highlight the possibility and importance of using probiotics in clinical prevention. Probiotics can be utilized as novel biocides to block and decrease biofilm formation and microbial contamination in medical equipment and during the treatment of infections. IMPORTANCE A. baumannii biofilm is a significant virulence factor that causes the biofilm colonization of invasive illnesses. Rising bacterial resistance to synthetic antimicrobials has prompted researchers to look at natural alternatives, such as probiotics and their derivatives. In this study, L. rhamnosus and its BSs (LA and AA) demonstrated remarkable antibiofilm and antimicrobial characteristics, with a significant inhibitory effect on A. baumannii. These effects were achieved by several mechanisms, including the disruption of the cell envelope membrane, protein lysis, reduced expression of biofilm-related genes, and destruction of bacterial DNA. The results provide support for the possibility of using probiotics and their derivatives in the clinical prevention and therapy of A. baumannii infections.}, } @article {pmid36916551, year = {2023}, author = {Nguyen Trang, P and Thi Anh Ngoc, T and Masuda, Y and Hohjoh, KI and Miyamoto, T}, title = {Biofilm Formation From Listeria monocytogenes Isolated From Pangasius Fish-processing Plants.}, journal = {Journal of food protection}, volume = {86}, number = {3}, pages = {100044}, doi = {10.1016/j.jfp.2023.100044}, pmid = {36916551}, issn = {1944-9097}, mesh = {Animals ; *Listeria monocytogenes ; Muramidase/pharmacology ; Chlorine/pharmacology ; Polylysine/pharmacology ; Stainless Steel ; Biofilms ; *Catfishes ; Water/pharmacology ; Colony Count, Microbial ; }, abstract = {Biofilm formation of Listeria monocytogenes in food processing environments cause potential source of cross-contamination to foodstuffs; hence, the control of biofilm is currently addressed to find effective solutions for preventing biofilm formation or eliminating the established one. Forty-five strains of Listeria monocytogenes isolated from Pangasius fish-processing plants were studied for their capability to form a biofilm on 96-well microtiter plate by using the conventional crystal violet staining. Additionally, the inhibitory effect of biofilm formation by food additives including monascus pigment and ε-polylysine was examined. The average OD value showing biofilm mass of all 45 strains L. monocytogenes increased with an increasing temperature and time (p < 0.05). Monascus pigment and ε-polylysine significantly decreased biofilm formation by 80 ± 5.5% and 20 ± 5.9%, respectively, at the tested concentration (p < 0.05) Further, the effects of lysozyme (0.1 mg/mL) alone or in combination with slightly acidic hypochlorous water (SAHW) with 40 mg/L available chlorine or sodium hypochlorite (NaOCl) with 100 mg/L available chlorine against 7-d established biofilm of L. monocytogenes were investigated. The results indicated that slightly acidic hypochlorous water alone exhibited significant antibacterial activity (p < 0.05), decreasing the viable count by 5.2 ± 0.5 log CFU/mL. It seems that sequential treatment of lysozyme and SAHW showed an additional efficacy against biofilm of L. monocytogenes on polystyrene plate surface, reducing 70% of biomass of biofilm and 7.6 ± 0.3 log of biofilm viable cells (p < 0.05). Additionally, SAHW exhibited greater bactericidal activity against viable biofilm cells than NaOCl did. This result reveals that SAHW is a promising disinfectant agent against L. monocytogenes and the potential alternative to NaOCl in practice.}, } @article {pmid36914689, year = {2023}, author = {Bano, N and Iqbal, D and Al Othaim, A and Kamal, M and Albadrani, HM and Algehainy, NA and Alyenbaawi, H and Alghofaili, F and Amir, M and Roohi, }, title = {Antibacterial efficacy of synthesized silver nanoparticles of Microbacterium proteolyticum LA2(R) and Streptomyces rochei LA2(O) against biofilm forming meningitis causing microbes.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {4150}, pmid = {36914689}, issn = {2045-2322}, mesh = {Humans ; Silver/pharmacology/chemistry ; *Metal Nanoparticles/chemistry ; Anti-Bacterial Agents/chemistry ; *Streptomyces ; Biofilms ; *Actinomycetales ; *Actinobacteria ; *Meningitis ; Microbial Sensitivity Tests ; }, abstract = {Actinobacteria obtained from the least explored Indian regions were studied for their ability to suppress meningitis-causing bacteria in nanoparticle form. Drug-resistant bacteria and long-term treatment with different medications make meningitis control complicated. Thus, new meningitis drugs are required to combat MDR bacteria. In this study, secondary metabolites isolated from actinomycetes strains, Microbacterium proteolyticum LA2(R) and Streptomyces rochei LA2(O), were employed to synthesize silver nanoparticles (AgNPs) at 37 °C for seven days incubation. UV-Vis spectroscopy, TEM, FTIR, and HPLC studies were used for the confirmation of the synthesis of AgNPs. Furthermore, these NPs demonstrated antibacterial and antibiofilm activities against meningitis-causing bacteria. The average size of LA2(R) and LA2(O) isolated secondary metabolites mediated AgNPs was observed to be 27 ± 1and 29 ± 2 nm by TEM analysis. FTIR study of RAgNPs and OAgNPs revealed that presence of peaks with positions of 1637.17 cm[1] and 1636.10 cm[1] for C=O amide group appearances in the amide I linkage. These NPs were effective against bacterial pathogens such as S. pneumoniae, H. influenzae, and N. meningitidis and confirmed by their MICs, i.e., 109.4, 120.60, and 138.80 μg/ml of RAgNPs and 105.80, 114.40 and 129.06 μg/ml of OAgNPs, respectively. Additionally, the production of biofilms is impeded by these nanoparticles on S. pneumoniae, H. influenzae, and N. meningitidis by 73.14%, 71.89% and 64.81%, respectively. These findings confirm the potential role of synthesized AgNPs against biofilm forming meningitis causing Multidrug resistance (MDR) microbes.}, } @article {pmid36914349, year = {2023}, author = {Wang, D and Fletcher, GC and Gagic, D and On, SLW and Palmer, JS and Flint, SH}, title = {Comparative genome identification of accessory genes associated with strong biofilm formation in Vibrio parahaemolyticus.}, journal = {Food research international (Ottawa, Ont.)}, volume = {166}, number = {}, pages = {112605}, doi = {10.1016/j.foodres.2023.112605}, pmid = {36914349}, issn = {1873-7145}, mesh = {*Vibrio parahaemolyticus/genetics ; Biofilms ; Genomics ; Operon ; Cellulose ; }, abstract = {Vibrio parahaemolyticus biofilms on the seafood processing plant surfaces are a potential source of seafood contamination and subsequent food poisoning. Strains differ in their ability to form biofilm, but little is known about the genetic characteristics responsible for biofilm development. In this study, pangenome and comparative genome analysis of V. parahaemolyticus strains reveals genetic attributes and gene repertoire that contribute to robust biofilm formation. The study identified 136 accessory genes that were exclusively present in strong biofilm forming strains and these were functionally assigned to the Gene Ontology (GO) pathways of cellulose biosynthesis, rhamnose metabolic and catabolic processes, UDP-glucose processes and O antigen biosynthesis (p < 0.05). Strategies of CRISPR-Cas defence and MSHA pilus-led attachment were implicated via Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation. Higher levels of horizontal gene transfer (HGT) were inferred to confer more putatively novel properties on biofilm-forming V. parahaemolyticus. Furthermore, cellulose biosynthesis, a neglected potential virulence factor, was identified as being acquired from within the order Vibrionales. The cellulose synthase operons in V. parahaemolyticus were examined for their prevalence (22/138, 15.94 %) and were found to consist of the genes bcsG, bcsE, bcsQ, bcsA, bcsB, bcsZ, bcsC. This study provides insights into robust biofilm formation of V. parahaemolyticus at the genomic level and facilitates: identification of key attributes for robust biofilm formation, elucidation of biofilm formation mechanisms and development of potential targets for novel control strategies of persistent V. parahaemolyticus.}, } @article {pmid36914121, year = {2023}, author = {Rožman, M and Lekunberri, I and Grgić, I and Borrego, CM and Petrović, M}, title = {Effects of combining flow intermittency and exposure to emerging contaminants on the composition and metabolic response of streambed biofilm bacterial communities.}, journal = {The Science of the total environment}, volume = {877}, number = {}, pages = {162818}, doi = {10.1016/j.scitotenv.2023.162818}, pmid = {36914121}, issn = {1879-1026}, mesh = {*Ecosystem ; *Water Pollutants, Chemical/analysis ; Dissolved Organic Matter ; Bacteria/genetics ; Rivers/chemistry ; Biofilms ; }, abstract = {Freshwater ecosystems are characterised by the co-occurrence of stressors that simultaneously affect the biota. Among these, flow intermittency and chemical pollution severely impair the diversity and functioning of streambed bacterial communities. Using an artificial streams mesocosm facility, this study examined how desiccation and pollution caused by emerging contaminants affect the composition of stream biofilm bacterial communities, their metabolic profiles, and interactions with their environment. Through an integrative analysis of the composition of biofilm communities, characterization of their metabolome and composition of the dissolved organic matter, we found strong genotype-to-phenotype interconnections. The strongest correlation was found between the composition and metabolism of the bacterial community, both of which were influenced by incubation time and desiccation. Unexpectedly, no effect of the emerging contaminants was observed, which was due to the low concentration of the emerging contaminants and the dominant impact of desiccation. However, biofilm bacterial communities modified the chemical composition of their environment under the effect of pollution. Considering the tentatively identified classes of metabolites, we hypothesised that the biofilm response to desiccation was mainly intracellular while the response to chemical pollution was extracellular. The present study demonstrates that metabolite and dissolved organic matter profiling may be effectively integrated with compositional analysis of stream biofilm communities to yield a more complete picture of changes in response to stressors.}, } @article {pmid36913883, year = {2023}, author = {Bajaj, A and Abutoama, M and Isaacs, S and Abuleil, MJ and Yaniv, K and Kushmaro, A and Modic, M and Cvelbar, U and Abdulhalim, I}, title = {Biofilm growth monitoring using guided wave ultralong-range Surface Plasmon Resonance: A proof of concept.}, journal = {Biosensors & bioelectronics}, volume = {228}, number = {}, pages = {115204}, doi = {10.1016/j.bios.2023.115204}, pmid = {36913883}, issn = {1873-4235}, mesh = {*Surface Plasmon Resonance/methods ; *Biosensing Techniques/methods ; Reproducibility of Results ; Silicon Dioxide ; Gold ; Biofilms ; }, abstract = {Unwelcomed biofilms are problematic in food industries, surgical devices, marine applications, and wastewater treatment plants, essentially everywhere where there is moisture. Very recently, label-free advanced sensors such as localized and extended surface plasmon resonance (SPR) have been explored as tools for monitoring biofilm formation. However, conventional noble metal SPR substrates suffer from low penetration depth (100-300 nm) into the dielectric medium above the surface, preventing the reliable detection of large entities of single or multi-layered cell assemblies like biofilms which can grow up to a few micrometers or more. In this study, we propose using a plasmonic insulator-metal-insulator (IMI) structure (SiO2-Ag-SiO2) with a higher penetration depth based on a diverging beam single wavelength format of Kretschmann configuration in a portable SPR device. An SPR line detection algorithm for locating the reflectance minimum of the device helps to view changes in refractive index and accumulation of the biofilm in real-time down to 10[-7] RIU precision. The optimized IMI structure exhibits strong penetration dependence on wavelength and incidence angle. Within the plasmonic resonance, different angles penetrate different depths, showing a maximum near the critical angle. At the wavelength of 635 nm, a high penetration depth of more than 4 μm was obtained. Compared to a thin gold film substrate, for which the penetration depth is only ∼200 nm, the IMI substrate provides more reliable results. The average thickness of the biofilm after 24 h of growth was found to be between 6 and 7 μm with ∼63% live cell volume, as estimated from confocal microscopic images using an image processing tool. To explain this saturation thickness, a graded index biofilm structure is proposed in which the refractive index decreases with the distance from the interface. Furthermore, when plasma-assisted degeneration of biofilms was studied in a semi-real-time format, there was almost no effect on the IMI substrate compared to the gold substrate. The growth rate over the SiO2 surface was higher than on gold, possibly due to differences between surface charge effects. On the gold, the excited plasmon generates an oscillating cloud of electrons, while for the SiO2 case, this does not happen. This methodology can be utilized to detect and characterize biofilms with better signal reliability with respect to concentration and size dependence.}, } @article {pmid36913810, year = {2023}, author = {Yan, X and Sun, J and Wang, Y and Zhang, Z and Zhang, C and Li, W and Xu, J and Dai, X and Ni, BJ}, title = {Low-rate ferrate dosing damages the microbial biofilm structure through humic substances destruction and facilitates the sewer biofilm control.}, journal = {Water research}, volume = {235}, number = {}, pages = {119834}, doi = {10.1016/j.watres.2023.119834}, pmid = {36913810}, issn = {1879-2448}, mesh = {*Humic Substances ; *Iron/pharmacology ; Wastewater ; Nitrous Acid ; Biofilms ; }, abstract = {The microbial activities in sewer biofilms are recognized as a major reason for sewer pipe corrosion, malodor, and greenhouse gas emissions. However, conventional methods to control sewer biofilm activities were based on the inhibitory or biocidal effect of chemicals and often required long exposure time or high dosing rates due to the protection of sewer biofilm structure. Therefore, this study attempt to use ferrate (Fe(VI)), a green and high-valent iron, at low dosing rates to damage the sewer biofilm structure so as to enhance sewer biofilm control efficiency. The results showed the biofilm structure started to crush when the Fe(VI) dosage was 15 mg Fe(VI)/L and the damage enhanced with the increasing dosage. The determination of extracellular polymeric substances (EPS) showed that Fe(VI) treatment at 15-45 mgFe/L mainly decreased the content of humic substances (HS) in biofilm EPS. This is because the functional groups, such as C-O, -OH, and C=O, which held the large molecular structure of HS, were the primary target of Fe(VI) treatment as suggested by 2D-Fourier Transform Infrared spectra. As a result, the coiled chain of EPS maintained by HS was turned to extended and dispersed and consequently led to a loosed biofilm structure. The XDLVO analysis suggested that both the microbial interaction energy barrier and secondary energy minimum were increased after Fe(VI) treatment, suggesting that the treated biofilm was less likely to aggregate and easier to be removed by the shear stress caused by high wastewater flow. Moreover, combined Fe(VI) and free nitrous acid (FNA) dosing experiments showed for achieving 90% inactivation, the FNA dosing rate could be reduced by 90% with the exposure time decreasing by 75% at a low Fe(VI) dosing rate and the total cost was substantially decreased. These results suggested that applying low-rate Fe(VI) dosing for sewer biofilm structure destruction is expected to be an economical way to facilitate sewer biofilm control.}, } @article {pmid36913408, year = {2023}, author = {Bing, J and Guan, Z and Zheng, T and Zhang, Z and Fan, S and Ennis, CL and Nobile, CJ and Huang, G}, title = {Clinical isolates of Candida auris with enhanced adherence and biofilm formation due to genomic amplification of ALS4.}, journal = {PLoS pathogens}, volume = {19}, number = {3}, pages = {e1011239}, pmid = {36913408}, issn = {1553-7374}, support = {R35 GM124594/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Candida/genetics ; *Antifungal Agents ; Candida auris ; Biofilms ; Genomics ; Microbial Sensitivity Tests ; }, abstract = {Candida auris is an emerging multidrug-resistant fungal pathogen and a new global threat to human health. A unique morphological feature of this fungus is its multicellular aggregating phenotype, which has been thought to be associated with defects in cell division. In this study, we report a new aggregating form of two clinical C. auris isolates with increased biofilm forming capacity due to enhanced adherence of adjacent cells and surfaces. Unlike the previously reported aggregating morphology, this new aggregating multicellular form of C. auris can become unicellular after treatment with proteinase K or trypsin. Genomic analysis demonstrated that amplification of the subtelomeric adhesin gene ALS4 is the reason behind the strain's enhanced adherence and biofilm forming capacities. Many clinical isolates of C. auris have variable copy numbers of ALS4, suggesting that this subtelomeric region exhibits instability. Global transcriptional profiling and quantitative real-time PCR assays indicated that genomic amplification of ALS4 results in a dramatic increase in overall levels of transcription. Compared to the previously characterized nonaggregative/yeast-form and aggregative-form strains of C. auris, this new Als4-mediated aggregative-form strain of C. auris displays several unique characteristics in terms of its biofilm formation, surface colonization, and virulence.}, } @article {pmid36911973, year = {2023}, author = {Ürer, EK and Aslantaş, Ö and Tek, E and Yılmaz, MA and Ergün, Y}, title = {Antimicrobial susceptibility and biofilm forming ability of staphylococci from subclinical buffalo mastitis.}, journal = {The Journal of dairy research}, volume = {}, number = {}, pages = {1-4}, doi = {10.1017/S0022029923000080}, pmid = {36911973}, issn = {1469-7629}, abstract = {The starting objective of this research communication was to determine the prevalence of subclinical mastitis in buffalo in Turkey. We also seeked to isolate and identify staphylococci, determine their antimicrobial susceptibilities and biofilm-forming abilities as well as investigating the presence of biofilm-related genes and microbial surface components recognizing adhesive matrix molecules. A total of 107 (66.9%) staphylococci (28 S. aureus and 79 coagulase-negative staphylococci, CoNS) were isolated from 160 mastitic milk samples collected from 200 lactating water buffalos. The staphylococci were especially resistant to beta-lactams except for cefoxitin but were less resistant to the other antimicrobials that were tested. Based on the Congo red agar method, 92.9% of the S. aureus and 70.9% of the CoNS isolates were positive for biofilm-forming ability, while all S. aureus and 97.5% of CoNS isolates were positive by a microtiter plate analysis. The presence of icaA and icaD genes was not always correlated with biofilm synthesis, and even in the absence of these genes, the isolates were able to synthesize biofilm.}, } @article {pmid36911868, year = {2023}, author = {Fukushima, S and Yamamoto, K and Nakano, Y and Hagiya, H and Otsuka, F}, title = {Biofilm-associated candidal thrombophlebitis.}, journal = {IDCases}, volume = {31}, number = {}, pages = {e01733}, pmid = {36911868}, issn = {2214-2509}, } @article {pmid36911333, year = {2023}, author = {Kim, JY and Moon, EC and Kim, JY and Kim, HJ and Heo, K and Shim, JJ and Lee, JL}, title = {Lactobacillus helveticus HY7801 ameliorates bacterial vaginosis by inhibiting biofilm formation and epithelial cell adhesion of Gardnerella vaginalis.}, journal = {Food science and biotechnology}, volume = {32}, number = {4}, pages = {507-515}, pmid = {36911333}, issn = {2092-6456}, abstract = {UNLABELLED: Bacterial vaginosis (BV) is caused by a microbial imbalance in the vaginal ecosystem, which causes genital discomfort and a variety of potential complications in women. This study validated the potential of Lactobacillus helveticus HY7801 as a probiotic to benefit vaginal health. In vivo, HY7801 reduced the number of Gardnerella vaginalis (GV) and pro-inflammatory cytokines in the vagina of GV-induced BV mice and ameliorated vaginal histological changes. In vitro, HY7801 exhibited positive resistance to simulated gastrointestinal conditions, showed excellent adherence ability to the female genital epithelium, and had high lactic acid and H2O2 production capacity. Furthermore, it was found that HY7801 can alleviate BV because it can suppress the expression of virulence factor genes of GV involved in epithelial cell adhesion and biofilm formation along with antibacterial activity against GV. These results indicate that HY7801 can be used as a promising probiotic strain for the maintenance of a healthy vaginal physiological state.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-022-01208-7.}, } @article {pmid36910511, year = {2023}, author = {Fleeman, RM and Mikesh, M and Davies, BW}, title = {Investigating Klebsiella pneumoniae biofilm preservation for scanning electron microscopy.}, journal = {Access microbiology}, volume = {5}, number = {2}, pages = {}, pmid = {36910511}, issn = {2516-8290}, abstract = {Klebsiella pneumoniae biofilm formation is associated with chronic and relapsing infections. Scanning electron microscopy (SEM) is a powerful tool for characterizing biofilm structure and studying their formation. Reliable visualization of biofilm structure requires careful sample preservation, otherwise there may be loss of non-covalent interactions that are susceptible to damage during the dehydration and washing preparation steps. However, no standard procedure has been adopted in the literature to fix K. pneumoniae biofilm for scanning electron microscopy studies. This lack of standardization makes it challenging to compare results between studies and determine the degree to which native structures have been preserved. To advance this critical area of study, we investigated different scanning electron microscopy fixation methods for K. pneumoniae biofilm preservation. Our study reveals the impact preparation steps can have on retaining in biofilm architecture observed using scanning electron microscopy. Using fixation methods developed through our studies, we show that although species that overproduce capsular extracellular polysaccharides produced more robust biofilms, K. pneumoniae can form a developed biofilm in the absence of capsular polysaccharides.}, } @article {pmid36910230, year = {2023}, author = {Mirzaei, R and Esmaeili Gouvarchin Ghaleh, H and Ranjbar, R}, title = {Antibiofilm effect of melittin alone and in combination with conventional antibiotics toward strong biofilm of MDR-MRSA and -Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1030401}, pmid = {36910230}, issn = {1664-302X}, abstract = {INTRODUCTION: Multidrug-resistant (MDR) pathogens are being recognized as a critical threat to human health if they can form biofilm and, in this sense, biofilm-forming MDR-methicillin resistant Staphylococcus aureus (MRSA) and -Pseudomonas aeruginosa strains are a worse concern. Hence, a growing body of documents has introduced antimicrobial peptides (AMPs) as a substitute candidate for conventional antimicrobial agents against drug-resistant and biofilm-associated infections. We evaluated melittin's antibacterial and antibiofilm activity alone and/or in combination with gentamicin, ciprofloxacin, rifampin, and vancomycin on biofilm-forming MDR-P. aeruginosa and MDR-MRSA strains.

METHODS: Antibacterial tests [antibiogram, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC)], anti-biofilm tests [minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC)], as well as synergistic antibiofilm activity of melittin and antibiotics, were performed. Besides, the influence of melittin alone on the biofilm encoding genes and the cytotoxicity and hemolytic effects of melittin were examined.

RESULTS: MIC, MBC, MBIC, and MBEC indices for melittin were in the range of 0.625-5, 1.25-10, 2.5-20, and 10-40 μg/ml, respectively. The findings found that the combination of melittin AMP with antibiotics was synergistic and fractional biofilm inhibitory concentration index (FBICi) for most tested concentrations was <0.5, resulting in a significant reduction in melittin, gentamicin, ciprofloxacin, vancomycin, and rifampin concentrations by 2-256.4, 2-128, 2-16, 4-64 and 4-8 folds, respectively. This phenomenon reduced the toxicity of melittin, whereby its synergist concentration required for biofilm inhibition did not show cytotoxicity and hemolytic activity. Our findings found that melittin decreased the expression of icaA in S. aureus and LasR in P. aeruginosa genes from 0.1 to 4.11 fold for icaA, and 0.11 to 3.7 fold for LasR, respectively.

CONCLUSION: Overall, the results obtained from our study show that melittin alone is effective against the strong biofilm of MDR pathogens and also offers sound synergistic effects with antibiotics without toxicity. Hence, combining melittin and antibiotics can be a potential candidate for further evaluation of in vivo infections by MDR pathogens.}, } @article {pmid36909500, year = {2023}, author = {Cassin, EK and Araujo-Hernandez, SA and Baughn, DS and Londono, MC and Rodriguez, DQ and Tseng, BS}, title = {OprF impacts Pseudomonas aeruginosa biofilm matrix eDNA levels in a nutrient-dependent manner.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36909500}, support = {K22 AI121097/AI/NIAID NIH HHS/United States ; P20 GM103440/GM/NIGMS NIH HHS/United States ; }, abstract = {UNLABELLED: The biofilm matrix is composed of exopolysaccharides, eDNA, membrane vesicles, and proteins. While proteomic analyses have identified numerous matrix proteins, their functions in the biofilm remain understudied compared to the other biofilm components. In the Pseudomonas aeruginosa biofilm, several studies have identified OprF as an abundant matrix protein and, more specifically, as a component of biofilm membrane vesicles. OprF is a major outer membrane porin of P. aeruginosa cells. However, current data describing the effects of OprF in the P. aeruginosa biofilm is limited. Here we identify a nutrient-dependent effect of OprF in static biofilms, whereby Δ oprF cells form significantly less biofilm than wild type when grown in media containing glucose or low sodium chloride concentrations. Interestingly, this biofilm defect occurs during late static biofilm formation and is not dependent on the production of PQS, which is responsible for outer membrane vesicle production. Furthermore, while biofilms lacking OprF contain approximately 60% less total biomass than those of wild type, the number of cells in these two biofilms is equivalent. We demonstrate that P. aeruginosa Δ oprF biofilms with reduced biofilm biomass contain less eDNA than wild-type biofilms. These results suggest that the nutrient-dependent effect of OprF is involved in the maintenance of mature P. aeruginosa biofilms by retaining eDNA in the matrix.

IMPORTANCE: Many pathogens form biofilms, which are bacterial communities encased in an extracellular matrix that protects them against antibacterial treatments. The roles of several matrix components of the opportunistic pathogen Pseudomonas aeruginosa have been characterized. However, the effects of P. aeruginosa matrix proteins remain understudied and are untapped potential targets for antibiofilm treatments. Here we describe a conditional effect of the abundant matrix protein OprF on late-stage P. aeruginosa biofilms. A Δ oprF strain formed significantly less biofilm in low sodium chloride or with glucose. Interestingly, the defective Δ oprF biofilms did not exhibit fewer resident cells but contained significantly less extracellular DNA (eDNA) than wild type. These results suggest that OprF is involved in matrix eDNA retention in mature biofilms.}, } @article {pmid36908866, year = {2023}, author = {Hamad, PA}, title = {Phenotypic and Molecular Detection of Biofilm Formation in Methicillin-Resistant Staphylococcus Aureus Isolated from Different Clinical Sources in Erbil City.}, journal = {Mediterranean journal of hematology and infectious diseases}, volume = {15}, number = {1}, pages = {e2023016}, pmid = {36908866}, issn = {2035-3006}, abstract = {BACKGROUND: Staphylococcus aureus is an important causative pathogen. The production of biofilms is an important factor and makes these bacteria resistant to antimicrobial therapy.

OBJECTIVES: the current study aimed to assess the prevalence of resistance to antibacterial agents and to evaluate the phenotypic and genotypic characterization of biofilm formation among S. aureus strains.

METHODS: This study included 50 isolates of Methicillin-resistant S. aureus (MRSA) and Methicillin-Susceptible S. aureus (MSSA). S. aureus was identified by molecular and conventional methods, and antimicrobial resistance was tested with a disc diffusion method. The biofilm formation was performed through the Microtiter plate method. Strains were subjected to PCR to determine the presence of nuc, mecA, icaA, icaB, icaC, and icaD genes.

RESULTS: Of the 50 S. aureus isolates, 32(64%) and 18(36%) were MRSA and MSSA, respectively. A large number of MRSA and MSSA isolates showed resistance to Penicillin and Azithromycin, and a lower number of MRSA and MSSA isolates showed resistance to Amikacin Gentamicin. None of the isolates was resistant to Vancomycin. The MRSA strains had significantly higher resistance against antibiotics than MSSA strains (P = 0.0154). All isolates (MRSA and MSSA) were able to produce biofilm with levels ranging from strong (31.25 %), (16.6%) to moderate (53.12%), (50%) to weak (15.6%), (33.3%) respectively. The MRSA strains had a significantly higher biofilm formation ability than the MSSA strains (P = 0.0079). The biofilm-encoding genes were detected among isolates with different frequencies. The majority of S. aureus isolates, 42 (84%), were positive for the icaA. The prevalence rates of the icaB, icaC and icaD genes were found to be 37 (74%), 40 (80%) and 41 (82%), respectively.

CONCLUSIONS: The prevalence of biofilm encoding genes associated with multidrug resistance in S. aureus strains is high. Therefore, identifying epidemiology, molecular characteristics, and biofilm management of S. aureus infection would be helpful.}, } @article {pmid36907929, year = {2023}, author = {Maurya, A and Kumar, R and Raj, A}, title = {Biofilm-based technology for industrial wastewater treatment: current technology, applications and future perspectives.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {5}, pages = {112}, pmid = {36907929}, issn = {1573-0972}, mesh = {*Wastewater ; Biofilms ; Bioreactors/microbiology ; Bacteria ; *Water Purification ; Waste Disposal, Fluid ; }, abstract = {The microbial community in biofilm is safeguarded from the action of toxic chemicals, antimicrobial compounds, and harsh/stressful environmental circumstances. Therefore, biofilm-based technology has nowadays become a successful alternative for treating industrial wastewater as compared to suspended growth-based technologies. In biofilm reactors, microbial cells are attached to static or free-moving materials to form a biofilm which facilitates the process of liquid and solid separation in biofilm-mediated operations. This paper aims to review the state-of-the-art of recent research on bacterial biofilm in industrial wastewater treatment including biofilm fundamentals, possible applications and problems, and factors to regulate biofilm formation. We discussed in detail the treatment efficiencies of fluidized bed biofilm reactor (FBBR), trickling filter reactor (TFR), rotating biological contactor (RBC), membrane biofilm reactor (MBfR), and moving bed biofilm reactor (MBBR) for different types of industrial wastewater treatment. Besides, biofilms have many applications in food and agriculture, biofuel and bioenergy production, power generation, and plastic degradation. Furthermore, key factors for regulating biofilm formation were also emphasized. In conclusion, industrial applications make evident that biofilm-based treatment technology is impactful for pollutant removal. Future research to address and improve the limitations of biofilm-based technology in wastewater treatment is also discussed.}, } @article {pmid36907420, year = {2023}, author = {Zhuang, LL and Tian, W and Yang, Y and Ge, S and Li, P and Sun, S and Zhang, J and Liang, S}, title = {Quantified trend of photosynthetic rate along the depth of microalgae biofilm.}, journal = {The Science of the total environment}, volume = {876}, number = {}, pages = {162801}, doi = {10.1016/j.scitotenv.2023.162801}, pmid = {36907420}, issn = {1879-1026}, mesh = {*Microalgae ; Photosynthesis ; Light ; Biofilms ; Biomass ; Oxygen ; }, abstract = {Compared with suspended microalgae cultivation, attached microalgae cultivation for wastewater treatment has advantages of low biomass recovery costs and high robustness. As a heterogeneous system, the variation of photosynthetic capacity along biofilm depth lacks quantitative conclusions. The distribution curve of oxygen concentration along the depth of attached microalgae biofilm (f(x)) was detected by dissolved oxygen (DO) microelectrode, and a quantified model was built based on mass conservation and Fick's law. It revealed that the net photosynthetic rate at a certain depth (x) in the biofilm showed a linear relationship with the second derivatives of the distribution curve of oxygen concentration (f″(x)). In addition, the declining trend of photosynthetic rate along attached microalgae biofilm was relatively slow compared with the suspended system. The photosynthetic rate at 150-200 μm depth of algae biofilm was only 3.60 %-17.86 % of that at the surface layer. Moreover, the light saturation points of the attached microalgae got lower along the depth of biofilm. Compared to 400 lx light intensity, the net photosynthetic rate of microalgae biofilm at the depths of 100-150 μm and 150-200 μm increased by 389 % and 956 % under 5000 lx, respectively, showing the high photosynthesis potential with increasing light.}, } @article {pmid36907360, year = {2023}, author = {Centeleghe, I and Norville, P and Hughes, L and Maillard, JY}, title = {Klebsiella pneumoniae survives on surfaces as a dry biofilm.}, journal = {American journal of infection control}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ajic.2023.02.009}, pmid = {36907360}, issn = {1527-3296}, abstract = {BACKGROUND: Dry surface biofilms (DSB) are widespread in healthcare settings presenting a challenge to cleaning and disinfection. Klebsiella pneumoniae has been a focus of attention due to antibiotic resistance and the emergence of hypervirulent strains. Few studies have demonstrated K pneumoniae survival on surfaces following desiccation.

METHODS: DSB were formed over 12 days. Bacterial culturability and transfer were investigated following DSB incubation up to 4 weeks. Bacterial viability in DSB was investigated with live/dead staining using flow cytometry.

RESULTS: K pneumoniae formed mature DSB. After 2 and 4 weeks of incubation, transfer from DSB was low (<55%) and reduced further (<21%) following wiping. Culturability at 2 and 4 weeks varied although viability remained high indicating viable but non culturable state (VBNC).

DISCUSSION: K pneumoniae was removed from surfaces by mechanical wiping as shown with DSB of other species. Although culturability was reduced over time, bacteria remained viable up to 4 weeks incubation, proving the need for robust cleaning regimens.

CONCLUSIONS: This is the first study confirming K pneumoniae survival on dry surfaces as a DSB. The presence of VBNC bacteria indicated that K pneumoniae can for extended periods, raising questions about its persistence on surfaces.}, } @article {pmid36906314, year = {2023}, author = {Liu, J and Wu, S and Feng, L and Wu, Y and Zhu, J}, title = {Extracellular matrix affects mature biofilm and stress resistance of psychrotrophic spoilage Pseudomonas at cold temperature.}, journal = {Food microbiology}, volume = {112}, number = {}, pages = {104214}, doi = {10.1016/j.fm.2023.104214}, pmid = {36906314}, issn = {1095-9998}, mesh = {*Pseudomonas ; *Cold Temperature ; Biofilms ; Extracellular Polymeric Substance Matrix ; Extracellular Matrix ; }, abstract = {Psychrotrophic Pseudomonas as the dominant spoilage bacteria, have biofilm forming ability, increasing persistence and contamination in the chilled food. Biofilm formation of spoilage Pseudomonas at cold temperature was documented, however, role of extracellular matrix in mature biofilm and stress resistance of psychrotrophic Pseudomonas are much less abundant. The aim of this study was to investigate the biofilm forming characteristics of three spoilers P. fluorescens PF07, P. lundensis PL28, and P. psychrophile PP26 at 25 °C, 15 °C and 4 °C, and to explore their stress resistance to chemical and thermal treatments of mature biofilms. The results showed that biofilm biomass of three Pseudomonas at 4 °C was significantly higher than that at 15 °C and 25 °C. The secretion of extracellular polymeric substances (EPS) greatly increased in those Pseudomonas under low temperature, of which extracellular protein constituted about 71.03%-77.44%. Compared to 25 °C, the mature biofilms were observed to more aggregation and thicker spatial structure at 4 °C ranging from 42.7 to 54.6 μm, in contrast to 25.0-29.8 μm at 25 °C, especially strain PF07. These Pseudomonas biofilms switched into moderate hydrophobicity, and their swarming and swimming were significantly inhibited at low temperature. Furthermore, the resistance to NaClO and heating at 65 °C apparently enhanced for mature biofilm formed at 4 °C, indicating the difference in EPS matrix production influenced the stress resistance of biofilm. In addition, three strains contained alg and psl operons for exopolysaccharide biosynthesis, and biofilm related genes of algK, pslA, rpoS, and luxR were significantly up-regulated, while flgA gene was down-regulated at 4 °C compared to 25 °C, consistent with the above phenotype changes. Thus, the dramatic increase of mature biofilm and their stress resistance in psychrotrophic Pseudomonas were associated with large secretion and protection of extracellular matrix under low temperature, which provide a theoretical basis for subsequent biofilm control during cold chain.}, } @article {pmid36906303, year = {2023}, author = {Zarei, M and Paknejad, M and Eskandari, MH}, title = {Sublethal chlorine stress promotes the biofilm-forming ability of Salmonella enterica serovars enteritidis and expression of the related genes.}, journal = {Food microbiology}, volume = {112}, number = {}, pages = {104232}, doi = {10.1016/j.fm.2023.104232}, pmid = {36906303}, issn = {1095-9998}, mesh = {*Salmonella enteritidis ; *Chlorine/pharmacology ; Serogroup ; Biofilms ; Quorum Sensing ; }, abstract = {Chlorine treatment is the most common disinfection method in food-related environments. In addition to being simple and inexpensive, this method is very effective if used properly. However, insufficient chlorine concentrations only cause a sublethal oxidative stress in the bacterial population and may alter the growth behavior of stressed cells. In the present study, the effect of sublethal chlorine stress on the biofilm formation characteristics of Salmonella Enteritidis was evaluated. Our results demonstrated that, sublethal chlorine stress (350 ppm total chlorine) activates the biofilm (csgD, agfA, adrA and bapA) and quorum-sensing (sdiA and luxS) related genes in planktonic cells of S. Enteritidis. The higher expression of these genes illustrated that the chlorine stress induced the initiation of the biofilm formation process in S. Enteritidis. Results of the initial attachment assay confirmed this finding. In addition, the number of chlorine-stressed biofilm cells was significantly higher than non-stressed biofilm cells after 48 h incubation at 37 °C. In S. Enteritidis ATCC 13076 and S. Enteritidis KL19, the number of chlorine-stressed biofilm cells were 6.93 ± 0.48 and 7.49 ± 0.57 log CFU/cm[2], while the number of non-stressed biofilm cells were 5.12 ± 0.39 and 5.63 ± 0.51 log CFU/cm[2], respectively. These findings were confirmed by measurements of the major components of biofilm, i.e., eDNA, protein and carbohydrate. The amount of these components in 48-h biofilms was higher when the cells were initially subjected to sublethal chlorine stress. However, the up-regulation of the biofilm and quorum sensing genes was not observed in 48-h biofilm cells, indicating that the effect of chlorine stress had vanished in the subsequent generations of Salmonella. In total, these results revealed that sublethal chlorine concentrations can promote the biofilm-forming ability of S Enteritidis.}, } @article {pmid36905831, year = {2023}, author = {Guo, W and Li, Y and Wang, S and Wang, Y and Li, C and Jin, Y and Li, Y and Chen, X and Miao, W}, title = {Photodynamic nano hydroxyapatite with biofilm penetration capability for dental plaque eradication and prevention of demineralization.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {225}, number = {}, pages = {113242}, doi = {10.1016/j.colsurfb.2023.113242}, pmid = {36905831}, issn = {1873-4367}, mesh = {Humans ; *Dental Caries/drug therapy/prevention & control ; *Dental Plaque/drug therapy/prevention & control ; Anti-Bacterial Agents/pharmacology ; Streptococcus mutans ; Biofilms ; }, abstract = {Dental caries represents one of the most prevalent diseases worldwide, characteristic of the growth of dental plaque and demineralization of tooth enamel. Current medications for eradication of dental plaques and prevention of demineralization suffer from several limitations to overcome, calling for novel strategies with great potency in eliminating cariogenic bacteria and dental plaque that forms, as well as in inhibiting the demineralization of enamel, into an integrated system. Considering the potency of photodynamic therapy in bacteria inactivation and the composition of enamel, we herein report that the novel photodynamic nano hydroxyapatite (nHAP), named Ce6 @QCS/nHAP, was useful for this purpose. Ce6 @QCS/nHAP, comprised of quaternary chitosan (QCS)-coated nHAP loaded with chlorin e6 (Ce6), exhibited good biocompatibility and non-compromised photodynamic activity. In vitro studies revealed that Ce6 @QCS/nHAP could effectively associate with cariogenic Streptococcus mutans (S. mutans), leading to a significant antibacterial effect through photodynamic killing and physical inactivation against the planktonic microbe. Three-dimensional fluorescence imaging suggested that Ce6 @QCS/nHAP exhibited a superior S. mutans biofilm penetration capacity to free Ce6, resulting in effective dental plaque eradiation when light irradiation was applied. The number of surviving bacteria in biofilm was at least 2.8 log units lower in the Ce6 @QCS/nHAP group compared to that in the free Ce6 group. Further, in the S. mutans biofilm-infected artificial tooth model, treatment with Ce6 @QCS/nHAP also resulted in the significant prevention of hydroxyapatite disks from demineralization, with lower percentage of fragmentation and weight loss These data suggest that our photodynamic nanosystem can effectively eradicate dental plaque while also significantly protecting artificial tooth from demineralization, opening up new possibilities in treating bacterium-associated dental caries.}, } @article {pmid36905317, year = {2023}, author = {Sharma, R and Johnson, RH and David, GR and Rahimifar, M and Heidari, A}, title = {A Case of Coccidioidal Meningitis With Biofilm Obstructing VP Shunt Due to Cutibacterium acnes.}, journal = {Journal of investigative medicine high impact case reports}, volume = {11}, number = {}, pages = {23247096231159810}, pmid = {36905317}, issn = {2324-7096}, mesh = {Humans ; *Propionibacterium acnes ; Biofilms ; Ventriculoperitoneal Shunt ; *Meningitis, Fungal ; }, abstract = {Herein described is a case of biofilm obstructing ventriculoperitoneal shunt due to Cutibacteirum acnes infection in a patient with coccidioidal meningitis. Cutibacterium acnes infects and obstructs cerebral shunts by the production of biofilm; however, diagnosis is usually missed by routine aerobic cultures. Obtaining anaerobic cultures routinely in patients with foreign body implants leading to central nervous system infections could prevent a missed diagnosis of this pathogen. Penicillin G is the first-line treatment.}, } @article {pmid36904487, year = {2023}, author = {Cremer, J and Kaltschmidt, BP and Kiel, A and Eberhard, J and Schmidt, S and Kaltschmidt, C and Kaltschmidt, B and Hütten, A and Anselmetti, D}, title = {Aging of Industrial Polypropylene Surfaces in Detergent Solution and Its Consequences for Biofilm Formation.}, journal = {Polymers}, volume = {15}, number = {5}, pages = {}, pmid = {36904487}, issn = {2073-4360}, support = {EFRE-1803FI12//European Regional Development Fund (EFRE)/ ; }, abstract = {The performance of plastic components in water-bearing parts of industrial and household appliances, often in the presence of harsh environments and elevated temperatures, critically relies on the mechanical and thermal polymer stability. In this light, the precise knowledge of aging properties of polymers formulated with dedicated antiaging additive packages as well as various fillers is crucial for long-time device warranty. We investigated and analysed the time-dependent, polymer-liquid interface aging of different industrial performance polypropylene samples in aqueous detergent solution at high temperatures (95 °C). Special emphasis was put on the disadvantageous process of consecutive biofilm formation that often follows surface transformation and degradation. Atomic force microscopy, scanning electron microscopy, and infrared spectroscopy were used to monitor and analyse the surface aging process. Additionally, bacterial adhesion and biofilm formation was characterised by colony forming unit assays. One of the key findings is the observation of crystalline, fibre-like growth of ethylene bis stearamide (EBS) on the surface during the aging process. EBS is a widely used process aid and lubricant enabling the proper demoulding of injection moulding plastic parts. The aging-induced surface-covering EBS layers changed the surface morphology and promoted bacterial adhesion as well as biofilm formation of Pseudomonas aeruginosa.}, } @article {pmid36904479, year = {2023}, author = {Mačák, L and Velgosova, O and Múdra, E and Vojtko, M and Dolinská, S}, title = {Transfer of AgNPs' Anti-Biofilm Activity into the Nontoxic Polymer Matrix.}, journal = {Polymers}, volume = {15}, number = {5}, pages = {}, pmid = {36904479}, issn = {2073-4360}, abstract = {A biological method was successfully applied to synthesize spherical silver nanoparticles (AgNPs) while using the extract of lavender (Ex-L) (lat. Lavandula angustifolia) as the reducing and stabilizing agent. The produced nanoparticles were spherical with an average size of 20 nm. The AgNPs' synthesis rate confirmed the extract's excellent ability to reduce silver nanoparticles from the AgNO3 solution. The presence of good stabilizing agents was confirmed by the excellent stability of the extract. Nanoparticles' shapes and sizes did not change. UV-Vis absorption spectrometry, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the silver nanoparticles. The silver nanoparticles were incorporated into the PVA polymer matrix by the "ex situ" method. The polymer matrix composite with AgNPs was prepared in two ways: as a composite film and nanofibers (nonwoven textile). The anti-biofilm activity of AgNPs and the ability of AgNPs to transfer toxic properties into the polymer matrix were proved.}, } @article {pmid36903742, year = {2023}, author = {Okamoto, K and Kudo, D and Phuong, DND and Iwamoto, Y and Watanabe, K and Yoshioka, Y and Ariyoshi, W and Yamasaki, R}, title = {Magnesium Hydroxide Nanoparticles Inhibit the Biofilm Formation of Cariogenic Microorganisms.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {13}, number = {5}, pages = {}, pmid = {36903742}, issn = {2079-4991}, support = {22K17020//Japan Society for the Promotion of Science/ ; //SETOLAS Holdings Inc./ ; //Takeda Science Foundation/ ; }, abstract = {Although various caries-preventive agents have been developed, dental caries is still a leading global disease, mostly caused by biological factors such as mutans streptococci. Magnesium hydroxide nanoparticles have been reported to exhibit antibacterial effects; however, they are rarely used in oral care practical applications. In this study, we examined the inhibitory effect of magnesium hydroxide nanoparticles on biofilm formation by Streptococcus mutans and Streptococcus sobrinus-two typical caries-causing bacteria. Three different sizes of magnesium hydroxide nanoparticles (NM80, NM300, and NM700) were studied, all of which inhibited biofilm formation. The results showed that the nanoparticles were important for the inhibitory effect, which was not influenced by pH or the presence of magnesium ions. We also determined that the inhibition process was mainly contact inhibition and that medium (NM300) and large (NM700) sizes were particularly effective in this regard. The findings of our study demonstrate the potential applications of magnesium hydroxide nanoparticles as caries-preventive agents.}, } @article {pmid36903577, year = {2023}, author = {Tran, HQ and Alam, H and Goff, A and Daeneke, T and Bhave, M and Yu, A}, title = {Multifunctional Fe3O4 Nanoparticles Filled Polydopamine Hollow Rods for Antibacterial Biofilm Treatment.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {5}, pages = {}, pmid = {36903577}, issn = {1420-3049}, mesh = {*Fosfomycin ; *Multifunctional Nanoparticles ; Drug Carriers/chemistry ; Anti-Bacterial Agents ; *Nanoparticles/chemistry ; }, abstract = {This work reports the use of mesoporous silica rods as templates for the step-wise preparation of multifunctional Fe3O4 NPs filled polydopamine hollow rods (Fe3O4@PDA HR). The capacity of as-synthesized Fe3O4@PDA HR as a new drug carrier platform was assessed by its loading and the triggered release of fosfomycin under various stimulations. It was found that the release of fosfomycin was pH dependent with ~89% of fosfomycin being released in pH 5 after 24 h, which was 2-fold higher than that in pH 7. The magnetic properties of Fe3O4 NPs and the photothermal properties of PDA enabled the triggered release of fosfomycin upon the exposure to rotational magnetic field, or NIR laser irradiation. Additionally, the capability of using multifunctional Fe3O4@PDA HR to eliminate preformed bacterial biofilm was demonstrated. Upon exposure to the rotational magnetic field, the biomass of a preformed biofilm was significantly reduced by 65.3% after a 20 min treatment with Fe3O4@PDA HR. Again, due to the excellent photothermal properties of PDA, a dramatic biomass decline (72.5%) was achieved after 10 min of laser exposure. This study offers an alternative approach of using drug carrier platform as a physical mean to kill pathogenic bacteria along with its traditional use for drug delivery.}, } @article {pmid36903518, year = {2023}, author = {Zhang, Z and Zhao, Y and Cai, J and Wang, T and Song, Y and Lu, J and Du, H and Wang, W and Zhao, Y and Guo, L}, title = {Optimized Extraction, Identification and Anti-Biofilm Action of Wu Wei Zi (Fructus Schisandrae Chinensis) Extracts against Vibrio parahaemolyticus.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {5}, pages = {}, pmid = {36903518}, issn = {1420-3049}, support = {SJCX21_1483//Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; }, mesh = {*Vibrio parahaemolyticus/genetics ; *Schisandra ; Biofilms ; }, abstract = {The pathogenicity of foodborne Vibrio parahaemolyticus is a major concern for global public health. This study aimed to optimize the liquid-solid extraction of Wu Wei Zi extracts (WWZE) against Vibrio parahaemolyticus, identify its main components, and investigate the anti-biofilm action. The extraction conditions optimized by the single-factor test and response surface methodology were ethanol concentration of 69%, temperature at 91 °C, time of 143 min, and liquid-solid ratio of 20:1 mL/g. After high performance liquid chromatography (HPLC) analysis, it was found that the main active ingredients of WWZE were schisandrol A, schisandrol B, schisantherin A, schisanhenol, and schisandrin A-C. The minimum inhibitory concentration (MIC) of WWZE, schisantherin A, and schisandrol B measured by broth microdilution assay was 1.25, 0.625, and 1.25 mg/mL, respectively, while the MIC of the other five compounds was higher than 2.5 mg/mL, indicating that schisantherin A and schizandrol B were the main antibacterial components of WWZE. Crystal violet, Coomassie brilliant blue, Congo red plate, spectrophotometry, and Cell Counting Kit-8 (CCK-8) assays were used to evaluate the effect of WWZE on the biofilm of V. parahaemolyticus. The results showed that WWZE could exert its dose-dependent potential to effectively inhibit the formation of V. parahaemolyticus biofilm and clear mature biofilm by significantly destroying the cell membrane integrity of V. parahaemolyticus, inhibiting the synthesis of intercellular polysaccharide adhesin (PIA), extracellular DNA secretion, and reducing the metabolic activity of biofilm. This study reported for the first time the favorable anti-biofilm effect of WWZE against V. parahaemolyticus, which provides a basis for deepening the application of WWZE in the preservation of aquatic products.}, } @article {pmid36902594, year = {2023}, author = {Popov, G and Aleksandrov, R and Petkova, V and Kaneva, R and Gergova, R and Kundurzhiev, T and Popova, D}, title = {Analysis of Bacterial Biofilm Formation and MUC5AC and MUC5B Expression in Chronic Rhinosinusitis Patients.}, journal = {Journal of clinical medicine}, volume = {12}, number = {5}, pages = {}, pmid = {36902594}, issn = {2077-0383}, support = {№D-79/24.06.2020//Medical University Sofia/ ; }, abstract = {Chronic rhinosinusitis (CRS) is a condition affecting as much as 16% of the adult population in developed countries with many factors attributed to its development, including the more recently proposed role of bacterial biofilm infections. Plenty of research has been conducted on biofilms in CRS and the causes behind the development of such an infection in the nasal cavity and sinuses. One such probable cause is the production of mucin glycoproteins by the mucosa of the nasal cavity. To investigate the possible link between biofilm formation and mucin expression levels and their relationship with CRS etiology, we examined samples from 85 patients by means of spinning disk confocal microscopy (SDCM) to establish their biofilm status and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to determine MUC5AC and MUC5B expression levels. We observed a significantly higher prevalence of bacterial biofilms in the CRS patient group compared to the control group. In addition, we detected higher expression levels of MUC5B but not MUC5AC in the CRS group, which suggested a possible role for MUC5B in CRS development. Finally, we found no direct relationship between biofilm presence and mucin expression levels, thereby showing a multifaceted connection between these two major factors implicated in CRS etiology.}, } @article {pmid36902413, year = {2023}, author = {Parvin, F and Rahman, MA and Deva, AK and Vickery, K and Hu, H}, title = {Staphylococcus aureus Cell Wall Phenotypic Changes Associated with Biofilm Maturation and Water Availability: A Key Contributing Factor for Chlorine Resistance.}, journal = {International journal of molecular sciences}, volume = {24}, number = {5}, pages = {}, pmid = {36902413}, issn = {1422-0067}, mesh = {Humans ; Staphylococcus aureus ; Chlorine ; Water ; Proteomics ; *Disinfectants ; Anti-Bacterial Agents ; *Staphylococcal Infections ; Biofilms ; Cell Wall ; }, abstract = {Staphylococcus aureus biofilms are resistant to both antibiotics and disinfectants. As Staphylococci cell walls are an important defence mechanism, we sought to examine changes to the bacterial cell wall under different growth conditions. Cell walls of S. aureus grown as 3-day hydrated biofilm, 12-day hydrated biofilm, and 12-day dry surface biofilm (DSB) were compared to cell walls of planktonic organisms. Additionally, proteomic analysis using high-throughput tandem mass tag-based mass spectrometry was performed. Proteins involved in cell wall synthesis in biofilms were upregulated in comparison to planktonic growth. Bacterial cell wall width (measured by transmission electron microscopy) and peptidoglycan production (detected using a silkworm larva plasma system) increased with biofilm culture duration (p < 0.001) and dehydration (p = 0.002). Similarly, disinfectant tolerance was greatest in DSB, followed by 12-day hydrated biofilm and then 3-day biofilm, and it was least in the planktonic bacteria--suggesting that changes to the cell wall may be a key factor for S. aureus biofilm biocide resistance. Our findings shed light on possible new targets to combat biofilm-related infections and hospital dry surface biofilms.}, } @article {pmid36902169, year = {2023}, author = {Charęza, M and Przygrodzka, K and Żywicka, A and Grygorcewicz, B and Sobolewski, P and Mozia, S and Śmiglak, M and Drozd, R}, title = {Enhancement of Inhibition of the Pseudomonas sp. Biofilm Formation on Bacterial Cellulose-Based Wound Dressing by the Combined Action of Alginate Lyase and Gentamicin.}, journal = {International journal of molecular sciences}, volume = {24}, number = {5}, pages = {}, pmid = {36902169}, issn = {1422-0067}, mesh = {Humans ; *Gentamicins/pharmacology ; Anti-Bacterial Agents/pharmacology ; Pseudomonas ; Cellulose/pharmacology ; Pseudomonas aeruginosa ; *Pseudomonas Infections/microbiology ; Biofilms ; Bandages ; }, abstract = {Bacterial biofilms generally contribute to chronic infections, including wound infections. Due to the antibiotic resistance mechanisms protecting bacteria living in the biofilm, they are a serious problem in the wound healing process. To accelerate the wound healing process and avoid bacterial infection, it is necessary to select the appropriate dressing material. In this study, the promising therapeutic properties of alginate lyase (AlgL) immobilised on BC membranes for protecting wounds from Pseudomonas aeruginosa infection were investigated. The AlgL was immobilised on never dried BC pellicles via physical adsorption. The maximum adsorption capacity of AlgL was 6.0 mg/g of dry BC, and the equilibrium was reached after 2 h. The adsorption kinetics was studied, and it has been proven that the adsorption was consistent with Langmuir isotherm. In addition, the impact of enzyme immobilisation on bacterial biofilm stability and the effect of simultaneous immobilisation of AlgL and gentamicin on the viability of bacterial cells was investigated. The obtained results showed that the AlgL immobilisation significantly reduced the amount of polysaccharides component of the P. aeruginosa biofilm. Moreover, the biofilm disruption by AlgL immobilised on BC membranes exhibited synergism with the gentamicin, resulting in 86.5% more dead P. aeruginosa PAO-1 cells.}, } @article {pmid36900736, year = {2023}, author = {Saengphen, T and Koontongkaew, S and Utispan, K}, title = {Effectiveness of a Combined Toothbrushing Technique on Cariogenic Dental Biofilm in Relation to Stainless Steel and Elastomeric Ligatures in Orthodontic Patients: A Randomized Clinical Trial.}, journal = {Healthcare (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {36900736}, issn = {2227-9032}, support = {WUICD- A2020//Walailak University, International College of Dentistry/ ; }, abstract = {Increased dental biofilm commonly occurs during orthodontic treatment. The aim of this study was to evaluate the effect of a combined toothbrushing method on dental biofilm cariogenicity in patients with stainless steel (SSL) and elastomeric (EL) ligatures. At baseline (T1), 70 participants were randomized (1:1 ratio) to the SSL or EL group. Dental biofilm maturity was evaluated using a three-color-disclosing dye. The participants were instructed to brush their teeth using a combined horizontal-Charters-modified Bass technique. Dental biofilm maturity was reassessed at the 4-week follow-up (T2). We found that at T1, new dental biofilm was the highest, followed by mature and cariogenic dental biofilm in the SSL group (p < 0.05). In the EL group, cariogenic dental biofilm was highly observed, followed by mature and new dental biofilm (p < 0.05). After intervention, cariogenic dental biofilm significantly decreased in both groups (p < 0.05). Moreover, a marked decrease in cariogenic dental biofilm was observed in the EL group compared with the SSL group (p < 0.05). However, the change in mature dental biofilm in the groups was similar (p > 0.05). Our results demonstrated that the combined toothbrushing method reduced cariogenic dental biofilm in the SSL and EL groups.}, } @article {pmid36898963, year = {2023}, author = {Budil, J and Štenclová, P and Kromka, A and Lišková, P}, title = {Development of the Pseudomonas syringae pv. morsprunorum Biofilm Monitored in Real Time Using Attenuated Total Reflection Fourier Transform Infrared Measurements in a Flow Cell Chamber.}, journal = {Applied spectroscopy}, volume = {77}, number = {5}, pages = {500-512}, doi = {10.1177/00037028231165057}, pmid = {36898963}, issn = {1943-3530}, mesh = {*Pseudomonas syringae ; Fourier Analysis ; Spectroscopy, Fourier Transform Infrared/methods ; *Biofilms ; Proteins ; }, abstract = {Biofilms of sessile Pseudomonas syringae cells formed on top of plant host's leaves or fruits allow surviving harsh environmental conditions (desiccation) and improve their resistance to antibacterial treatments of crops. A better understanding of these biofilms can help minimize their effect on harvests. In the present study, infrared attenuated total reflection spectroscopy coupled with optical and confocal laser scanning microscopy has been applied for the first time to analyze Pseudomonas syringae pathovar morsprunorum biofilm development in real time. The biofilm development was observed within a spectral window 4000-800 cm[-1] under constant flow conditions for 72 h. The kinetics of representative integrated band areas (nucleic acids with polysaccharides at 1141-1006 cm[-1], amino acid side chains with free fatty acids at 1420-1380 cm[-1], proteins at 1580-1490 cm[-1], and lipids with proteins at 2935-2915 cm[-1]) were analyzed with regard to the observed biofilm structure and the following P. syringae biofilm developmental stages were attributed: The inoculation phase, washing of weakly attached bacteria closely followed by recolonization of the vacated surface, the restructuration phase, and finally the maturation phase.}, } @article {pmid36898591, year = {2023}, author = {Ragupathi, NKD and Muthuirulandi Sethuvel, DP and Gopikrishnan, M and Dwarakanathan, HT and Murugan, D and Biswas, I and Bakthavachalam, YD and Murugesan, M and George Priya Doss, C and Monk, PN and Karunakaran, E and Veeraraghavan, B}, title = {Phage-based therapy against biofilm producers in gram-negative ESKAPE pathogens.}, journal = {Microbial pathogenesis}, volume = {178}, number = {}, pages = {106064}, doi = {10.1016/j.micpath.2023.106064}, pmid = {36898591}, issn = {1096-1208}, mesh = {Colistin/pharmacology ; Phylogeny ; Anti-Bacterial Agents/pharmacology ; *Bacteriophages/genetics ; *Phage Therapy ; Bacteria ; }, abstract = {Persistent antibiotic use results in the rise of antimicrobial resistance with limited or no choice for multidrug-resistant (MDR) and extensively drug resistant (XDR) bacteria. This necessitates a need for alternative therapy to effectively combat clinical pathogens that are resistant to last resort antibiotics. The study investigates hospital sewage as a potential source of bacteriophages to control resistant bacterial pathogens. Eighty-one samples were screened for phages against selected clinical pathogens. Totally, 10 phages were isolated against A. baumannii, 5 phages against K. pneumoniae, and 16 phages were obtained against P. aeruginosa. The novel phages were observed to be strain-specific with complete bacterial growth inhibition of up to 6 h as monotherapy without antibiotics. Phage plus colistin combinations reduced the minimum-biofilm eradication concentration of colistin up to 16 folds. Notably, a cocktail of phages exhibited maximum efficacy with complete killing at 0.5-1 μg/ml colistin concentrations. Thus, phages specific to clinical strains have a higher edge in treating nosocomial pathogens with their proven anti-biofilm efficacy. In addition, analysis of phage genomes revealed close phylogenetic relations with phages reported from Europe, China, and other neighbouring countries. This study serves as a reference and can be extended to other antibiotics and phage types to assess optimum synergistic combinations to combat various drug resistant pathogens in the ongoing AMR crisis.}, } @article {pmid36897105, year = {2023}, author = {Halder, M and Narula, M and Singh, Y}, title = {Supramolecular, Nanostructured Assembly of Antioxidant and Antibacterial Peptides Conjugated to Naproxen and Indomethacin for the Selective Inhibition of COX-2, Biofilm, and Inflammation in Chronic Wounds.}, journal = {Bioconjugate chemistry}, volume = {}, number = {}, pages = {}, doi = {10.1021/acs.bioconjchem.3c00014}, pmid = {36897105}, issn = {1520-4812}, abstract = {Chronic wounds are a major healthcare challenge around the world. The presence of bacterial biofilms, accumulation of reactive oxygen species (ROS), and persistent inflammation have been identified as rate-limiting steps in chronic wound healing. Anti-inflammatory drugs, like naproxen (Npx) and indomethacin (Ind), show poor selectivity for the COX-2 enzyme, which plays a key role in producing inflammatory responses. To address these challenges, we have developed conjugates of Npx and Ind with peptides possessing antibacterial, antibiofilm, and antioxidant properties along with enhanced selectivity for the COX-2 enzyme. We have synthesized and characterized peptide conjugates Npx-YYk, Npx-YYr, Ind-YYk, and Ind-YYr, which were self-assembled into supramolecular gels. As envisaged, the conjugates and gels showed high proteolytic stability and selectivity toward the COX-2 enzyme and potent antibacterial activities (>95% within 12 h) against Gram-positive bacteria Staphylococcus aureus, implicated in wound-related infections, eradication of biofilm (∼80%), and radical scavenging (>90%) properties. Cell culture studies with mouse fibroblast cells (L929) and macrophage-like cells (RAW 264.7) showed that gels were cell proliferative in nature (120% viability), which resulted in faster and more efficient scratch healing. Treatment with gels led to a significant decrease in proinflammatory cytokine (TNF-α and IL-6) expressions and an increase in anti-inflammatory gene (IL-10) expression. The gels developed in this work show great promise as a topical agent for chronic wounds or as a coating for medical devices to prevent medical-device-associated infections.}, } @article {pmid36894813, year = {2023}, author = {Kalashnikova, TV and Sutormina, LV and Samoilova, ZY and Oktyabrsky, ON and Smirnova, GV}, title = {Effect of Changes in the Redox Status on Biofilm Formation in Escherichia coli.}, journal = {Bulletin of experimental biology and medicine}, volume = {174}, number = {4}, pages = {451-454}, pmid = {36894813}, issn = {1573-8221}, mesh = {*Escherichia coli/genetics/metabolism ; *Escherichia coli Proteins/genetics/metabolism/pharmacology ; Biofilms ; Oxidation-Reduction ; }, abstract = {Changes in the redox balance in the medium and in Escherichia coli cells significantly affect the ability of bacteria to form biofilms. An increase in the level of aeration in the culture of wild-type bacteria led to a 3-fold decrease in the mass of biofilms. Mutants lacking components of the glutathione and thioredoxin redox systems, as well as transporters involved in the transmembrane cycling of glutathione, demonstrated increased biofilm formation ability. The effect of exogenous glutathione on biofilm formation depended on the culturing conditions. The addition of 0.1-1 mM Trolox (a water-soluble analog of vitamin E) was accompanied by a 30-40% reduction in biofilm formation.}, } @article {pmid36893978, year = {2023}, author = {Abdelhak, S and Menard, Y and Artigas, J}, title = {Effects of global change on the ability of stream biofilm to dissipate the herbicide glyphosate.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {324}, number = {}, pages = {121406}, doi = {10.1016/j.envpol.2023.121406}, pmid = {36893978}, issn = {1873-6424}, mesh = {*Rivers/chemistry ; *Herbicides ; Ecosystem ; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid ; Water/chemistry ; Organic Chemicals ; Biofilms ; }, abstract = {The herbicide glyphosate is contaminating a large number of freshwater ecosystems worldwide and its fate and effects remains uncertain in light of the effects of global change. The present study examines how variations in water temperature and light availability relative to global change affect the ability of stream biofilms to degrade the herbicide glyphosate. Biofilms were exposed in microcosms to two levels of water temperature simulating global warming (Ambient = 19-22 °C and Warm = 21-24 °C) and three levels of light representative of riparian habitat destruction due to land use change (Dark = 0, Intermediate = 600, High = 1200 μmol photons m[-2] s[-1]). Biofilms were acclimated to six different experimental treatments, namely i) ambient temperature without light (AMB_D), ii) ambient temperature and intermediate light (AMB_IL), iii) ambient temperature and high light (AMB_HL), iv) warm temperature without light (WARM_D), v) warm temperature and intermediate light (WARM_IL) and vi) warm temperature and high light (WARM_HL). The ability of biofilms to degrade 50 μg L[-1] of glyphosate was tested. Results showed that water temperature increase, but not light availability increase, significantly increased aminomethyl phosphonic acid (AMPA) production by biofilms. However, the combined increase of temperature and light generated the shortest time to dissipate half of the glyphosate supplied and/or half of the maximum AMPA produced (6.4 and 5.4 days, respectively) by biofilms. Despite light had a major effect in modulating biofilm structural and functional descriptors, the response of certain descriptors (i. e. chlorophyll-a concentration, bacterial density and diversity, nutrient content and PHO activity) to light availability increase depended on water temperature. Specifically, the biofilms in the WARM_HL treatment displayed the highest Glucosidase: Peptidase and Glucosidase: Phosphatase enzyme activity ratios and the lowest biomass C: N molar ratios compared to the other treatments. According to these results, warmer temperatures and high light availability could have been exacerbating the decomposition of organic C compounds in biofilms, including the use of glyphosate as a C source for microbial heterotrophs. This study shows that ecoenzymatic stoichiometry and xenobiotic biodegradation approaches can be combined to better understand the functioning of biofilms in pesticide-polluted streams.}, } @article {pmid36893665, year = {2023}, author = {Meng, X and Xiong, H and Ji, F and Gao, X and Han, L and Wu, Z and Jia, L and Ren, J}, title = {Facile surface treatment strategy to generate dense lysozyme layer on ultra-high molecular weight polyethylene enabling inhibition of bacterial biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {225}, number = {}, pages = {113243}, doi = {10.1016/j.colsurfb.2023.113243}, pmid = {36893665}, issn = {1873-4367}, mesh = {Humans ; *Muramidase/pharmacology ; Polyethylenes/pharmacology/chemistry ; Biofilms ; *Anti-Infective Agents/pharmacology ; Bacteria ; }, abstract = {Medical plastics such as those found in endotracheal tubes are widely used in intensive care units for the treatment of critically ill patients. Although commonplace in hospital environment, these catheters are at a high risk of bacterial contamination and have been found responsible for numerous health-care-associated infections. Antimicrobial coatings that can prevent harmful bacterial growth are required to reduce the occurrence of such infections. In this study, we introduce a facile surface treatment strategy that could form antimicrobial coatings on the surface of average medical plastics. The strategy involves treatment of activated surfaces with lysozyme, a natural antimicrobial enzyme presenting in human lacrimal gland secretions which is widely used for wound healing. Using ultra-high molecular weight polyethylene (UHMWPE) as the representative surface, oxygen/argon plasma treatment for 3 min led to the increase of surface roughness and the generation of negatively charged groups, with the zeta potential measured as -94.5 mV at pH 7. The activated surface could accommodate lysozyme with a density of up to 0.3 nmol/cm[2] through electrostatic interaction. Antimicrobial activity of the resulting surface (UHMWPE@Lyz) was characterized with Escherichia coli and Pseudomonas sp. strains, and the treated surface significantly inhibited the bacterial colonization and the formation of biofilm compared to the untreated UHMWPE. This method of constructing an effective lysozyme-based antimicrobial coating is a generally applicable, simple and fast process for surface treatment with no adverse solvent and wastes involved.}, } @article {pmid36893426, year = {2023}, author = {Li, X and Kong, R and Wang, J and Wu, J and He, K and Wang, X}, title = {The formation mechanism of Bacillus subtilis biofilm surface morphology under competitive environment.}, journal = {Canadian journal of microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1139/cjm-2023-0014}, pmid = {36893426}, issn = {1480-3275}, abstract = {Material properties and growth environments affect the surface morphology of biofilms. Taken the biofilm growing in competitive environments as the object, which is compared with the single biofilm, we find that the competitive environment has an impact on the biofilm thickness and wrinkle patterns. Through diffusion-limited growth theoretical model analysis, it shows that the competitive environment is caused by cells competing for nutrition, and the competitive environment reacts on biofilms, which affect the phenotypic differentiation, causing changes in the stiffness of the biofilm. Using the theoretical and finite element simulation, we compare these results of bi-layer and tri-layer film-substrate models with experimental observations, and find that tri-layer film-substrate model is in line with the reality, which means that the layer between the biofilm and substrate plays an import role for wrinkle formation. Based on the above analysis, we further study effects of biofilm stiffness and interlayer thickness on wrinkles under competitive environment.}, } @article {pmid36890534, year = {2023}, author = {Zhu, M and Dang, J and Dong, F and Zhong, R and Zhang, J and Pan, J and Li, Y}, title = {Antimicrobial and cleaning effects of ultrasonic-mediated plasma-loaded microbubbles on Enterococcus faecalis biofilm: an in vitro study.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {133}, pmid = {36890534}, issn = {1472-6831}, support = {81901064//National Natural Science Foundation of China/ ; QML20210304//Beijing Hospitals Authority Youth Programme/ ; }, mesh = {Humans ; *Enterococcus faecalis ; Hydrogen Peroxide/pharmacology ; Ultrasonics ; Microbubbles ; Root Canal Irrigants/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Sodium Hypochlorite/pharmacology ; Dental Pulp Cavity ; Dentin ; Microscopy, Confocal ; }, abstract = {BACKGROUND: Enterococcus faecalis (E. faecalis) is the most frequently isolated bacteria from teeth with root canal treatment failure. This study aims to evaluate the disinfection effect of ultrasonic-mediated cold plasma-loaded microbubbles (PMBs) on 7d E. faecalis biofilm, the mechanical safety and the mechanisms.

METHODS: The PMBs were fabricated by a modified emulsification process and the key reactive species, nitric oxide (NO) and hydrogen peroxide (H2O2) were evaluated. The 7d E. faecalis biofilm on human tooth disk was constructed and divided into the following groups: PBS, 2.5%NaOCl, 2%CHX, and different concentrations of PMBs (10[8] mL[-1], 10[7] mL[-1]). The disinfection effects and elimination effects were verified with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Microhardness and roughness change of dentin after PMBs treatment were verified respectively.

RESULTS: The concentration of NO and H2O2 in PMBs increased by 39.99% and 50.97% after ultrasound treatment (p < 0.05) respectively. The CLSM and SEM results indicate that PMBs with ultrasound treatment could remove the bacteria and biofilm components effectively, especially those living in dentin tubules. The 2.5% NaOCl presented an excellent effect against biofilm on dishes, but the elimination effect on dentin tubules is limited. The 2% CHX group exhibits significant disinfection effect. The biosafety tests indicated that there is no significant changes on microhardness and roughness after PMBs with ultrasound treatment (p > 0.05).

CONCLUSION: PMBs combined with ultrasound treatment exhibited significant disinfection effect and biofilm removal effect, the mechanical safety is acceptable.}, } @article {pmid36890147, year = {2023}, author = {Maknuna, L and Tran, VN and Lee, BI and Kang, HW}, title = {Inhibitory effect of 405 nm laser light on bacterial biofilm in urethral stent.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {3908}, pmid = {36890147}, issn = {2045-2322}, mesh = {Humans ; *Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Light ; Stents/adverse effects ; Escherichia coli ; *Urinary Tract Infections ; Pseudomonas aeruginosa ; }, abstract = {The clinical use of urethral stents is usually complicated by various adverse effects, including dysuria, fever, and urinary tract infection (UTI). Biofilms (formed by bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) adhering to the stent cause UTIs in stented patients (approximately 11%). The undesirable consequences of antibiotics use include bacterial resistance, weight gain, and type 1 diabetes, which occur when antibiotics are used for a long time. We aimed to assess the efficacy of a new optical treatment with a 405 nm laser to inhibit bacterial growth in a urethral stent in vitro. The urethral stent was grown in S. aureus broth media for three days to induce biofilm formation under dynamic conditions. Various irradiation times with the 405 nm laser light were tested (5, 10, and 15 min). The efficacy of the optical treatment on biofilms was evaluated quantitatively and qualitatively. The production of reactive oxygen species helped eliminate the biofilm over the urethral stent after 405 nm irradiation. The inhibition rate corresponded to a 2.2 log reduction of colony-forming units/mL of bacteria after 0.3 W/cm[2] of irradiation for 10 min. The treated stent showed a significant reduction in biofilm formation compared with the untreated stent, as demonstrated by SYTO 9 and propidium iodide staining. MTT assays using the CCD-986sk cell line revealed no toxicity after 10 min of irradiation. We conclude that optical treatment with 405 nm laser light inhibits bacterial growth in urethral stents with no or minimal toxicity.}, } @article {pmid36889408, year = {2023}, author = {Feng, L and Sun, FY and Yang, J and Cui, D and Li, ZH and Pi, S and Zhao, HP and Li, A}, title = {Intracellular electron competition in response to the oxygen pressure of the aerobic denitrification process in an O2-based membrane biofilm reactor (MBfR) for nitrate removal.}, journal = {The Science of the total environment}, volume = {875}, number = {}, pages = {162592}, doi = {10.1016/j.scitotenv.2023.162592}, pmid = {36889408}, issn = {1879-1026}, mesh = {*Nitrates ; *Denitrification ; Oxygen ; Electrons ; Biofilms ; Bioreactors ; Nitrogen ; }, abstract = {This study quantitatively investigated the effect of dissolved oxygen (DO) concentration on aerobic denitrification, and showed the mechanism of aerobic denitrification from the perspective of electron competition by cultivating Pseudomonas stutzeri T13, a typical aerobic denitrifier, in an oxygen-based membrane biofilm reactor (O2-based MBfR). The experiments showed that when the O2 pressure increased from 2 to 10 psig , the average effluent DO concentration during steady-state phases increased from 0.02 to 4.23 mg/L, and the corresponding mean NO3[-]-N removal efficiency slightly decreased from 97.2 % to 90.9 %. Compared to the maximum theoretical flux of O2 in various phases, the actual O2 transfer flux increased from a limited status (2.07 e[-] eq m[-2] d[-1] at 2 psig) to an excessive status (5.58 e[-] eq m[-2] d[-1] at 10 psig). The increase of DO inhibited the electron availability for aerobic denitrification, which decreased from 23.97 % to 11.46 %, accompanying the increased electron availability for aerobic respiration from 15.87 % to 28.36 %. Unlike the napA and norB genes, the expression of the nirS and nosZ genes was significantly affected by DO, with the highest relative fold-changes of 6.5 and 6.13 at 4 psig O2, respectively. The results contribute to clarifying the mechanism of aerobic denitrification from the quantitative perspective of electron distribution and the qualitative perspective of gene expression, which benefits the control and practical application of aerobic denitrification for wastewater treatment.}, } @article {pmid36889402, year = {2023}, author = {Afonso, AC and Gomes, IB and Saavedra, MJ and C Simões, L and Simões, M}, title = {Drinking-water isolated Delftia acidovorans selectively coaggregates with partner bacteria and facilitates multispecies biofilm development.}, journal = {The Science of the total environment}, volume = {875}, number = {}, pages = {162646}, doi = {10.1016/j.scitotenv.2023.162646}, pmid = {36889402}, issn = {1879-1026}, mesh = {*Drinking Water ; *Delftia acidovorans ; Biofilms ; Bacteria ; Citrobacter freundii ; }, abstract = {Coaggregation plays an important role in the development of multispecies biofilms in different environments, often serving as an active bridge between biofilm members and other organisms that, in their absence, would not integrate the sessile structure. The ability of bacteria to coaggregate has been reported for a limited number of species and strains. In this study, 38 bacterial strains isolated from drinking water (DW) were investigated for their ability to coaggregate, in a total of 115 pairs of combinations. Among these isolates, only Delftia acidovorans (strain 005P) showed coaggregating ability. Coaggregation inhibition studies have shown that the interactions mediating D. acidovorans 005P coaggregation were both polysaccharide-protein and protein-protein, depending on the interacting partner bacteria. Dual-species biofilms of D. acidovorans 005P and other DW bacteria were developed to understand the role of coaggregation on biofilm formation. Biofilm formation by Citrobacter freundii and Pseudomonas putida strains highly benefited from the presence of D. acidovorans 005P, apparently due to the production of extracellular molecules/public goods favouring microbial cooperation. This was the first time that the coaggregation capacity of D. acidovorans was demonstrated, highlighting its role in providing a metabolic opportunity for partner bacteria.}, } @article {pmid36888841, year = {2023}, author = {Santos, VCED and Maquera-Huacho, PM and Imbriani, MJM and Minhaco, VMTR and Spolidorio, DMP}, title = {Effects of BlueM® against Streptococcus mutans biofilm and its virulence gene expression.}, journal = {Brazilian dental journal}, volume = {34}, number = {1}, pages = {19-28}, pmid = {36888841}, issn = {1806-4760}, mesh = {Humans ; Streptococcus mutans/genetics ; Virulence ; *Anti-Infective Agents/pharmacology ; Biofilms ; Gene Expression ; *Dental Caries ; Anti-Bacterial Agents/pharmacology ; }, abstract = {This study evaluated the antimicrobial capacity of BlueM® mouthwash against the bacterium Streptococcus mutans and its influence on gbpA gene expression as well as its cytotoxic effect on fibroblast cells. BlueM® showed antimicrobial activity, with MIC and MBC values of 0.005% and 0.01%, respectively. The MBIC was 6.25% for S. mutans. CFU count and confocal microscopy revealed significant effect of BlueM® on S. mutans biofilm pre-formed on dentin surfaces. Interestingly, the analysis of gbpA gene expression indicated a decrease in gene expression after 15 min of treatment with BlueM® at a concentration of 25%. Moreover, BlueM® exhibited low levels of cytotoxicity. In conclusion, our results showed the antimicrobial effectiveness of BlueM® against S. mutans, its ability to modulate the expression of the gbpA gene and its low cytotoxicity. This study supports the therapeutic potential of BlueM® as an alternative agent for the control of oral biofilm.}, } @article {pmid36884153, year = {2023}, author = {Memar, MY and Yekani, M and Farajnia, S and Ghadiri Moghaddam, F and Nabizadeh, E and Sharifi, S and Maleki Dizaj, S}, title = {Antibacterial and biofilm-inhibitory effects of vancomycin-loaded mesoporous silica nanoparticles on methicillin-resistant staphylococcus aureus and gram-negative bacteria.}, journal = {Archives of microbiology}, volume = {205}, number = {4}, pages = {109}, pmid = {36884153}, issn = {1432-072X}, support = {61957//Tabriz University of Medical Sciences/ ; }, mesh = {Humans ; Vancomycin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Silicon Dioxide/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Nanoparticles ; Microbial Sensitivity Tests ; Gram-Negative Bacteria ; Bacteria ; Biofilms ; }, abstract = {The present study aimed to prepare and characterize vancomycin-loaded mesoporous silica nanoparticles (Van-MSNs) to detect inhibitory effects on the planktonic and biofilm forms of methicillin-resistant Staphylococcus aureus (MRSA) isolates, and study the biocompatibility and toxicity of Van-MSNs in vitro as well as antibacterial activity of Van-MSNs against Gram-negative bacteria. The inhibitory effects of Van-MSNs were investigated on MRSA using the determination of minimum inhibitory (MIC) and minimum biofilm-inhibitory concentrations (MBIC) as well as the effect on bacterial attachment. Biocompatibility was studied by examining the effect of Van-MSNs on the lysis and sedimentation rate of red blood cells (RBC). The interaction of Van-MSNs with human blood plasma was detected by the SDS-PAGE approach. The cytotoxic effect of the Van-MSNs on human bone marrow mesenchymal stem cells (hBM-MSCs) was evaluated by the MTT assay. The antibacterial effects of vancomycin and Van-MSNs on Gram-negative bacteria were also investigated using MIC determination using the broth microdilution method. Furthermore, bacteria outer membrane (OM) permeabilization was determined. Van-MSNs showed inhibitory effects on planktonic and biofilm forms of bacteria on all isolates at levels lower than MICs and MBICs of free vancomycin, but the antibiofilm effect of Van-MSNs was not significant. However, Van-MSNs did not affect bacterial attachment to surfaces. Van-loaded MSNs did not show a considerable effect on the lysis and sedimentation of RBC. A low interaction of Van-MSNs was detected with albumin (66.5 kDa). The hBM-MSCs viability in exposure to different levels of Van-MSNs was 91-100%. MICs of ≥ 128 µg/mL were observed for vancomycin against all Gram-negative bacteria. In contrast, Van-MSNs exhibited modest antibacterial activity inhibiting the tested Gram-negative bacterial strains, at concentrations of ≤ 16 µg/mL. Van-MSNs increased the OM permeability of bacteria that can increase the antimicrobial effect of vancomycin. According to our findings, Van-loaded MSNs have low cytotoxicity, desirable biocompatibility, and antibacterial effects and can be an option for the battle against planktonic MRSA.}, } @article {pmid36883149, year = {2022}, author = {Makhrmash, JH and Al-Aidy, SR and Qaddoori, BH}, title = {Investigation of Biofilm Virulence Genes Prevalence in Klebsiella pneumoniae Isolated from the Urinary Tract Infections.}, journal = {Archives of Razi Institute}, volume = {77}, number = {4}, pages = {1421-1427}, pmid = {36883149}, issn = {2008-9872}, mesh = {Animals ; *Biofilms ; *Klebsiella pneumoniae/genetics/pathogenicity ; Prevalence ; RNA, Ribosomal, 16S ; *Urinary Tract Infections/epidemiology/microbiology ; Virulence ; }, abstract = {Klebsiella pneumonia is a pathogen and an agent that causes hospital-acquired infections. Klebsiella pneumonia is the first and most common causative agent in community-acquired infections and urinary tract diseases. This study aimed to detect common genes, (i.e., fimA, mrkA, and mrkD) in the isolates of K. pneumoniae, isolated from urine specimens using the polymerase chain reaction (PCR) method. The isolates of K. pneumoniae were collected from urine specimens in health centers in Wasit Governorate, Iraq, and diagnosed using Analytical Profile Index 20Eand 16S rRNA techniques. The microtiter plate (MTP) method was used to detect biofilm formation. A total of 56 isolates were identified as K. pneumonia cases. The results led to the detection of biofilms; accordingly, all K. pneumoniae isolates showed biofilm production by MTP, however, at different levels. The PCR method was employed to detect biofilm genes and showed that 49 (87.5%), 26 (46.4%), and 30 (53.6%) of isolates carried fimH, mrkA, and mrkD, respectively. Furthermore, susceptibility tests for different antibiotics revealed that K. pneumoniae isolates were resistant to amoxicillin-clavulanic acid (n=11, 19.5%), ceftazidime (n=13, 22.4%), ofloxacin (n=16, 28.1%), and tobramycin (n=27, 48.4%). It was also found all K. pneumonia isolates were sensitive to polymyxin B (92.6%), imipenem (88.3%), meropenem (79.4%), and amikacin (60.5%).}, } @article {pmid36882931, year = {2023}, author = {Magagula, S and Petzer, IM and Famuyide, IM and Karzis, J}, title = {Biofilm expression and antimicrobial resistance patterns of Streptococcus uberis isolated from milk samples of dairy cows in South Africa.}, journal = {The Journal of dairy research}, volume = {}, number = {}, pages = {1-5}, doi = {10.1017/S0022029923000158}, pmid = {36882931}, issn = {1469-7629}, support = {NRF-COP Grant number: 120319//National Research Foundation/ ; }, abstract = {The research described in this Research Communication addresses the hypothesis that intramammary infections with Streptococcus uberis (S. uberis) are associated with biofilm formation, which limits antibiotic efficacy. This retrospective study investigated biofilm expression and antimicrobial resistance (AMR) patterns of 172 S. uberis infections. Isolates were recovered from milk samples of subclinical, clinical, and intramammary infection cases on 30 commercial dairy herds. We determined the presence and intensity of biofilm expression of S. uberis isolates in vitro in three somatic cell count categories to recognise their AMR patterns. An automated minimum inhibitory concentration system with a commercially available panel of 23 antimicrobial agents evaluated AMR, while biofilm determination was conducted using a microplate method. The study established that all the S. uberis isolates assessed expressed biofilm with the following varying degrees of intensities: 30 (17.8%) strong, 59 (34.9%) medium and 80 (47.3%) weak biofilms. The newly registered UBAC mastitis vaccine containing biofilm adhesion components may, therefore, be a viable option for proactive mastitis management under field conditions. No differences were identified between biofilm intensity and the three somatic cell count groups. Most S. uberis isolates indicated a high-level sensitivity to the antimicrobial agents tested. Resistances were present in 8.7, 8.1 and 7.0% cases to rifampin, minocycline and tetracycline, respectively. Multidrug resistance was observed in 6.4%, emphasising AMR to antibiotics used in human medicine only. The low overall resistance suggests that farmers adhere to the prudent use of antimicrobials in the dairy industry.}, } @article {pmid36881023, year = {2023}, author = {Contreas, L and Hook, AL and Winkler, DA and Figueredo, G and Williams, P and Laughton, CA and Alexander, MR and Williams, PM}, title = {Linear Binary Classifier to Predict Bacterial Biofilm Formation on Polyacrylates.}, journal = {ACS applied materials & interfaces}, volume = {15}, number = {11}, pages = {14155-14163}, pmid = {36881023}, issn = {1944-8252}, abstract = {Bacterial infections are increasingly problematic due to the rise of antimicrobial resistance. Consequently, the rational design of materials naturally resistant to biofilm formation is an important strategy for preventing medical device-associated infections. Machine learning (ML) is a powerful method to find useful patterns in complex data from a wide range of fields. Recent reports showed how ML can reveal strong relationships between bacterial adhesion and the physicochemical properties of polyacrylate libraries. These studies used robust and predictive nonlinear regression methods that had better quantitative prediction power than linear models. However, as nonlinear models' feature importance is a local rather than global property, these models were hard to interpret and provided limited insight into the molecular details of material-bacteria interactions. Here, we show that the use of interpretable mass spectral molecular ions and chemoinformatic descriptors and a linear binary classification model of attachment of three common nosocomial pathogens to a library of polyacrylates can provide improved guidance for the design of more effective pathogen-resistant coatings. Relevant features from each model were analyzed and correlated with easily interpretable chemoinformatic descriptors to derive a small set of rules that give model features tangible meaning that elucidate relationships between the structure and function. The results show that the attachment of Pseudomonas aeruginosa and Staphylococcus aureus can be robustly predicted by chemoinformatic descriptors, suggesting that the obtained models can predict the attachment response to polyacrylates to identify anti-attachment materials to synthesize and test in the future.}, } @article {pmid36879323, year = {2023}, author = {Ghezzi, D and Boi, M and Sassoni, E and Valle, F and Giusto, E and Boanini, E and Baldini, N and Cappelletti, M and Graziani, G}, title = {Customized biofilm device for antibiofilm and antibacterial screening of newly developed nanostructured silver and zinc coatings.}, journal = {Journal of biological engineering}, volume = {17}, number = {1}, pages = {18}, pmid = {36879323}, issn = {1754-1611}, abstract = {BACKGROUND: Bacterial colonisation on implantable device surfaces is estimated to cause more than half of healthcare-associated infections. The application of inorganic coatings onto implantable devices limits/prevents microbial contaminations. However, reliable and high-throughput deposition technologies and experimental trials of metal coatings for biomedical applications are missing. Here, we propose the combination of the Ionized Jet Deposition (IJD) technology for metal-coating application, with the Calgary Biofilm Device (CBD) for high-throughput antibacterial and antibiofilm screening, to develop and screen novel metal-based coatings.

RESULTS: The films are composed of nanosized spherical aggregates of metallic silver or zinc oxide with a homogeneous and highly rough surface topography. The antibacterial and antibiofilm activity of the coatings is related with the Gram staining, being Ag and Zn coatings more effective against gram-negative and gram-positive bacteria, respectively. The antibacterial/antibiofilm effect is proportional to the amount of metal deposited that influences the amount of metal ions released. The roughness also impacts the activity, mostly for Zn coatings. Antibiofilm properties are stronger on biofilms developing on the coating than on biofilms formed on uncoated substrates. This suggests a higher antibiofilm effect arising from the direct contact bacteria-coating than that associated with the metal ions release. Proof-of-concept of application to titanium alloys, representative of orthopaedic prostheses, confirmed the antibiofilm results, validating the approach. In addition, MTT tests show that the coatings are non-cytotoxic and ICP demonstrates that they have suitable release duration (> 7 days), suggesting the applicability of these new generation metal-based coatings for the functionalization of biomedical devices.

CONCLUSIONS: The combination of the Calgary Biofilm Device with the Ionized Jet Deposition technology proved to be an innovative and powerful tool that allows to monitor both the metal ions release and the surface topography of the films, which makes it suitable for the study of the antibacterial and antibiofilm activity of nanostructured materials. The results obtained with the CBD were validated with coatings on titanium alloys and extended by also considering the anti-adhesion properties and biocompatibility. In view of upcoming application in orthopaedics, these evaluations would be useful for the development of materials with pleiotropic antimicrobial mechanisms.}, } @article {pmid36878870, year = {2023}, author = {Qiu, X and Han, X and Zhang, X and Teng, LA and Sriwastva, MK and Zhen, L and Li, Z and Liu, M and Ren, Y and Wang, S}, title = {Lactobacillus rhamnosus GG alleviates colitis caused by chemotherapy via biofilm formation.}, journal = {Journal of gastroenterology and hepatology}, volume = {}, number = {}, pages = {}, doi = {10.1111/jgh.16164}, pmid = {36878870}, issn = {1440-1746}, support = {H2019048//Jiangsu Provincial Health Commission/ ; LGY2019049//Six One Project, Top Talent Scientific Research Project for High-level Talents in Jiangsu Province/ ; }, abstract = {BACKGROUND AND AIM: Severe colitis is a common side effect of chemotherapy in cancer patients. In this study, we attempted to enhance the viability of probiotics in a gastric acid environment and improve the colitis induced by dextran sulfate sodium (DSS) and docetaxel.

METHODS: We purified Lactobacillus from yogurt and estimated their growth at pH 6.8 and pH 2.0. In the further investigation, the bacterial biofilm formation was used to define the mechanism by which administration of Lactobacillus rhamnosus (LGG) via oral gavage alleviates the colitis and intestine permeability of the mice induced by DSS and docetaxel. The potential benefit of probiotics on the treatment of breast cancer metastasis has been assessed as well.

RESULTS: Lactobacillus from yogurt growth was unexpectedly faster in the pH 2.0 than in the neutral pH medium during the first hour. LGG administered in the fasting state via oral gavage significantly improved the preventive effect in the colitis caused by DSS and docetaxel. LGG reduced the permeability of the intestine and decreased the expression of proinflammatory cytokines, TNF-α, IL-1β, and IL-6, in colitis by biofilm formation. Increasing the docetaxel dose may reduce breast tumor growth and metastasis in the lung but did not benefit survival due to severe colitis. However, the LGG supplement significantly improved the survival of tumor-bearing mice following a high dose of docetaxel treatment.

CONCLUSIONS: Our findings provide new insights into the potential mechanism of probiotic protection of the intestine and provide a novel therapeutic strategy to augment the chemotherapeutic treatment of tumors.}, } @article {pmid36878335, year = {2023}, author = {Al-Saafin, BA and Al-Bakri, AG and Abdelrazig, S and Dahabiyeh, LA}, title = {Investigating the effect of the probiotic Lactobacillus plantarum and the prebiotic fructooligosaccharides on Pseudomonas aeruginosa metabolome, virulence factors and biofilm formation as potential quorum sensing inhibitors.}, journal = {Microbial pathogenesis}, volume = {177}, number = {}, pages = {106057}, doi = {10.1016/j.micpath.2023.106057}, pmid = {36878335}, issn = {1096-1208}, mesh = {Quorum Sensing ; Virulence Factors/metabolism ; Pseudomonas aeruginosa ; *Lactobacillus plantarum/metabolism ; Biofilms ; Metabolome ; *Probiotics ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) uses quorum sensing signaling (QS) molecules to control the expression of virulence factors and biofilm formation. In this study, the effects of the probiotic's (Lactobacillus plantarum (L. plantarum)) lysate and cell-free supernatant and the prebiotic (Fructooligosaccharides (FOS)) on the levels of P. aeruginosa QS molecules, virulence factors, biofilm density and metabolites were observed. These effects were investigated using exofactor assays, crystal violet and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach. Results showed that in comparison to untreated P. aeruginosa, the L. plantarum cell-free supernatant (5%) and FOS (2%) significantly reduced the levels of the virulence factor pyoverdine (PVD) and several metabolites in the QS pathway including Pseudomonas autoinducer-2 (PAI-2). Metabolomics study revealed that the level of different secondary metabolites involved in the biosynthesis of vitamins, amino acids and the tricarboxylic acid (TCA) cycle were also affected. L. Plantarum was found to have a higher impact on the metabolomics profile of P. aeruginosa and its QS molecules compared to FOS. Lastly, a decrease in the formation of the P. aeruginosa biofilm was observed in a time-dependent pattern upon treatment with either cell-free supernatant of L. plantarum (5%), FOS (2%) or a combination of both treatments (5% + 2%). The latter showed the highest effect with 83% reduction in biofilm density at 72 h incubation. This work highlighted the important role probiotics and prebiotics play as potential QS inhibitors for P. aeruginosa. Moreover, it demonstrated the significant role of LC-MS metabolomics for investigating the altered biochemical and QS pathways in P. aeruginosa.}, } @article {pmid36878334, year = {2023}, author = {Lau, TV and Puah, SM and Tan, JMA and Merino, S and Puthucheary, SD and Chua, KH}, title = {Flagellar motility mediates biofilm formation in Aeromonas dhakensis.}, journal = {Microbial pathogenesis}, volume = {177}, number = {}, pages = {106059}, doi = {10.1016/j.micpath.2023.106059}, pmid = {36878334}, issn = {1096-1208}, mesh = {*Gentian Violet ; *Aeromonas/genetics ; Biofilms ; Cell Movement ; Flagella/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Aeromonas dhakensis possesses dual flagellar systems for motility under different environments. Flagella-mediated motility is necessary for biofilm formation through an initial attachment of bacteria to the surface, but this has not been elucidated in A. dhakensis. This study investigates the role of polar (flaH, maf1) and lateral (lafB, lafK and lafS) flagellar genes in the biofilm formation of a clinical A. dhakensis strain WT187 isolated from burn wound infection. Five deletion mutants and corresponding complemented strains were constructed using pDM4 and pBAD33 vectors, respectively, and analyzed for motility and biofilm formation using crystal violet staining and real-time impedance-based assays. All mutants were significantly reduced in swimming (p < 0.0001), swarming (p < 0.0001) and biofilm formation using crystal violet assay (p < 0.05). Real-time impedance-based analysis revealed WT187 biofilm was formed between 6 to 21 h, consisting of early (6-10 h), middle (11-18 h), and late (19-21 h) stages. The highest cell index of 0.0746 was recorded at 22-23 h and biofilms began to disperse starting from 24 h. Mutants Δmaf1, ΔlafB, ΔlafK and ΔlafS exhibited reduced cell index values at 6-48 h when compared to WT187 which indicates less biofilm formation. Two complemented strains cmaf1 and clafB exhibited full restoration to wild-type level in swimming, swarming, and biofilm formation using crystal violet assay, hence suggesting that both maf1 and lafB genes are involved in biofilm formation through flagella-mediated motility and surface attachment. Our study shows the role of flagella in A. dhakensis biofilm formation warrants further investigations.}, } @article {pmid36877588, year = {2023}, author = {Ding, Y and Ma, R and Liu, G and Li, X and Xu, K and Liu, P and Cai, K}, title = {Fabrication of a New Hyaluronic Acid/Gelatin Nanocomposite Hydrogel Coating on Titanium-Based Implants for Treating Biofilm Infection and Excessive Inflammatory Response.}, journal = {ACS applied materials & interfaces}, volume = {15}, number = {10}, pages = {13783-13801}, doi = {10.1021/acsami.2c23320}, pmid = {36877588}, issn = {1944-8252}, mesh = {Rats ; Animals ; Nanogels ; *Gelatin/pharmacology ; *Hyaluronic Acid/pharmacology ; Titanium/pharmacology ; Anti-Bacterial Agents/pharmacology ; Hydrogels/pharmacology ; Inflammation/drug therapy ; }, abstract = {Persistent inflammation caused by implant-associated biofilm infections has emerged as a significant clinical issue. While many methods have been developed to give implants great anti-biofilm benefits, the post-inflammatory microenvironment is frequently disregarded. Oxidative stress (OS) due to excessive reactive oxygen species (ROS) is considered to be one of the specific physiological signals of the inflammation microenvironment. Herein, ZIF-90-Bi-CeO2 nanoparticles (NPs) were incorporated into a Schiff-base chemically crosslinked hydrogel composed of aldehyde-based hyaluronic acid and gelatin. Through chemical crosslinking between polydopamine and gelatin, the hydrogel coating adhered to the Ti substrate. The modified Ti substrate gained multimodal antibacterial and anti-biofilm functions, which were attributed to the photothermal effect of Bi NPs, and the release of Zn ions and CeO2 NPs. Notably, CeO2 NPs endowed the system with dual-enzyme (SOD- and CAT-like) catalytic activities. In a rat implant-associated infection (IAI) model, the dual-functional hydrogel had a biofilm-removal ability and regulated OS and inflammatory responses to facilitate osseointegration. The photothermal therapy combined with a host inflammation-microenvironment regulation strategy might provide a novel treatment for biofilm infection and the accompanying excessive inflammation.}, } @article {pmid36877407, year = {2023}, author = {Han, J and Luo, J and Du, Z and Chen, Y and Liu, T}, title = {Synergistic Effects of Baicalin and Levofloxacin Against Hypervirulent Klebsiella pneumoniae Biofilm In Vitro.}, journal = {Current microbiology}, volume = {80}, number = {4}, pages = {126}, pmid = {36877407}, issn = {1432-0991}, support = {82104499//National Natural Science Foundation of China/ ; ZZH2020004//Guangxi Health Commission Key Lab of Fungi and Mycosis Research and Prevention/ ; YYZS2020006//The First Affiliated Hospital of Guangxi Medical University Provincial and Ministerial Key Laboratory Cultivation Project: Guangxi Key Laboratory of Tropical Fungi and Mycosis Research/ ; Z20210909//Guangxi Health Commission Self-financing Project/ ; }, mesh = {*Klebsiella pneumoniae/genetics ; *Levofloxacin/pharmacology ; Biofilms ; Flavonoids/pharmacology ; }, abstract = {Hypervirulent Klebsiella pneumoniae (hvKp) strains that form biofilms have recently emerged worldwide; however, the mechanisms underlying biofilm formation and disruption remain elusive. In this study, we established a hvKp biofilm model, investigated its in vitro formation pattern, and determined the mechanism of biofilm destruction by baicalin (BA) and levofloxacin (LEV). Our results revealed that hvKp exhibited a strong biofilm-forming ability, forming early and mature biofilms after 3 and 5 d, respectively. Early biofilm and bacterial burden were significantly reduced by BA + LEV and EM + LEV treatments, which destroyed the 3D structure of early biofilms. Conversely, these treatments were less effective against mature biofilm. The expression of both AcrA and wbbM was significantly downregulated in the BA + LEV group. These findings indicated that BA + LEV might inhibit the formation of hvKp biofilm by altering the expression of genes regulating efflux pumps and lipopolysaccharide biosynthesis.}, } @article {pmid36875729, year = {2023}, author = {Haroon, U and Munis, MFH and Liaquat, F and Khizar, M and Elahi, M and Chaudhary, HJ}, title = {Biofilm formation and flocculation potential analysis of halotolerant Bacillus tequilensis and its inoculation in soil to mitigate salinity stress of chickpea.}, journal = {Physiology and molecular biology of plants : an international journal of functional plant biology}, volume = {29}, number = {2}, pages = {277-288}, pmid = {36875729}, issn = {0971-5894}, abstract = {UNLABELLED: Application of beneficial microbes in soil is an important avenue to control plant stresses. In this study, the salinity tolerance of halotolerant bacteria (Bacillus tequilensis) was investigated and the bacterium was inoculated in the soil to mitigate salinity stress. The results revealed the highest floc yield and biofilm formation ability of B. tequilensis at 100 mM NaCl concentration. Fourier transformed infrared spectroscopy depicted the presence of carbohydrates and proteins which binds with sodium ions (Na[+]) and provide tolerance against salinity. Using PCR, plant growth-promoting bacterial genes viz., 1-aminocyclopropane-1-carboxylate deaminase and pyrroloquinoline quinone were successfully amplified from the genome of B. tequilensis. In the saline soil, B. tequilensis was inoculated and chickpea plants were grown. The bacterial strain improved the physiology, biochemistry, and antioxidant enzyme activities of the chickpea plant under salt stress. Plants inoculated with B. tequilensis exhibited higher relative water content, higher photosynthetic pigments, lower levels of hydrogen peroxide (H2O2) and malondialdehyde, and improved enzymatic activity for the scavenging of reactive oxygen species. The findings of this study suggest the sustainable use of B. tequilensis to mitigate the salinity stress of chickpea and other crops. This bacterium not only helps in the alleviation of the toxic effects of salt but also increases plant growth along with a reduction in crop losses due to salinity.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-023-01280-1.}, } @article {pmid36875516, year = {2023}, author = {Wells, M and Schneider, R and Bhattarai, B and Currie, H and Chavez, B and Christopher, G and Rumbaugh, K and Gordon, V}, title = {Perspective: The viscoelastic properties of biofilm infections and mechanical interactions with phagocytic immune cells.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1102199}, pmid = {36875516}, issn = {2235-2988}, support = {R01 AI121500/AI/NIAID NIH HHS/United States ; }, mesh = {*Phagocytes ; *Phagocytosis ; Biofilms ; Kinetics ; Pseudomonas aeruginosa ; }, abstract = {Biofilms are viscoelastic materials that are a prominent public health problem and a cause of most chronic bacterial infections, in large part due to their resistance to clearance by the immune system. Viscoelastic materials combine both solid-like and fluid-like mechanics, and the viscoelastic properties of biofilms are an emergent property of the intercellular cohesion characterizing the biofilm state (planktonic bacteria do not have an equivalent property). However, how the mechanical properties of biofilms are related to the recalcitrant disease that they cause, specifically to their resistance to phagocytic clearance by the immune system, remains almost entirely unstudied. We believe this is an important gap that is ripe for a large range of investigations. Here we present an overview of what is known about biofilm infections and their interactions with the immune system, biofilm mechanics and their potential relationship with phagocytosis, and we give an illustrative example of one important biofilm-pathogen (Pseudomonas aeruginosa) which is the most-studied in this context. We hope to inspire investment and growth in this relatively-untapped field of research, which has the potential to reveal mechanical properties of biofilms as targets for therapeutics meant to enhance the efficacy of the immune system.}, } @article {pmid36873470, year = {2023}, author = {Rezende Mires de Carvalho, R and Silva Dias, C and Nogueira Paz, L and Melo de Lima Fires, T and Pereira Figueira, C and Araújo Damasceno, K and Hanzen Pinna, M}, title = {Biofilm formation in vitro by Leptospira interrogans strains isolated from naturally infected dogs and their role in antimicrobial resistance.}, journal = {Heliyon}, volume = {9}, number = {3}, pages = {e13802}, pmid = {36873470}, issn = {2405-8440}, abstract = {Leptospira interrogans is a biofilm-forming pathogen, however, there are few data involving Brazilian strains isolated from dogs and their antimicrobial sensitivity in planktonic and biofilm forms. The potential for biofilm formation and antimicrobial resistance in naturally infected dogs is a fundamental approach towards disease epidemiology and the establishment of consistent prophylaxis and control measures. The objective of this study was to evaluate in vitro biofilm formation of a reference strain (L. interrogans, sv. Copenhageni L1 130 - L20) and of L. interrogans isolated from dogs (C20, C29, C51, C82), with subsequent evaluation of antimicrobial susceptibility in planktonic and biofilm forms. The semi quantification of biofilm production revealed a dynamic process of development over time, with mature biofilm formation early on the seventh day of incubation. All strains were efficient for in vitro biofilm formation and, in this form, they were considerably more resistant compared to their planktonic form, with MIC90 of 1600 μg/mL for amoxicillin, 800 μg/mL for ampicillin, and >1600 μg/mL for doxycycline and ciprofloxacin. The strains studies were isolated on naturally infected dogs that might act as reservoirs and sentinels for human infections. The potential to antimicrobial resistance together with the close relation between dogs and humans indicates the need for greater actions on disease control and surveillance. Moreover, biofilm formation may contribute to the persistence of Leptospira interrogans in the host and these animals can act as chronic carriers, disseminating the agent in the environment.}, } @article {pmid36870235, year = {2023}, author = {Yang, H and Zhan, X and Song, L and Cheng, S and Su, R and Zhang, Y and Guo, D and Lü, X and Xia, X and Shi, C}, title = {Synergistic antibacterial and anti-biofilm mechanisms of ultrasound combined with citral nanoemulsion against Staphylococcus aureus 29213.}, journal = {International journal of food microbiology}, volume = {391-393}, number = {}, pages = {110150}, doi = {10.1016/j.ijfoodmicro.2023.110150}, pmid = {36870235}, issn = {1879-3460}, mesh = {*Staphylococcus aureus ; *Anti-Bacterial Agents/chemistry ; Acyclic Monoterpenes ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {This study investigated the antibacterial and antibiofilm mechanism of ultrasound (US) combined with citral nanoemulsion (CLNE) against Staphylococcus aureus and mature biofilm. Combined treatments resulted in greater reductions in bacterial numbers compared to ultrasound or CLNE treatments alone. Confocal laser scanning microscopy (CLSM), flow cytometry (FCM), protein nucleic acid leakage, and N-phenyl-l-naphthylamine (NPN) uptake analysis showed that the combined treatment disrupted cell membrane integrity and permeability. Reactive oxygen species (ROS) and malondialdehyde (MDA) assays indicated that US+CLNE exacerbated cellular oxidative stress and membrane lipid peroxidation. Field emission scanning electron microscopy (FESEM) revealed that the synergistic processing of ultrasound and CLNE resulted in cell rupture and collapse. In addition, US+CLNE showed a more pronounced removal effect than both alone in the biofilm on the stainless steel sheet. US+CLNE reduced biomass, the number of viable cells in the biofilm, cell viability and EPS polysaccharide contents. The results of CLSM also showed that US+CLNE disrupted the structure of the biofilm. This research elucidates the synergistic antibacterial and anti-biofilm mechanism of ultrasound combined citral nanoemulsion, which provides a safe and efficient sterilization method for the food industry.}, } @article {pmid36870201, year = {2023}, author = {Verma, NK and Dewangan, RP and Harioudh, MK and Ghosh, JK}, title = {Introduction of a β-leucine residue instead of leucine[9] and glycine[10] residues in Temporin L for improved cell selectivity, stability and activity against planktonic and biofilm of methicillin resistant S. aureus.}, journal = {Bioorganic chemistry}, volume = {134}, number = {}, pages = {106440}, doi = {10.1016/j.bioorg.2023.106440}, pmid = {36870201}, issn = {1090-2120}, mesh = {Animals ; Mice ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Leucine/pharmacology ; Glycine ; Plankton ; Anti-Bacterial Agents/pharmacology/chemistry ; Lipids ; Peptide Hydrolases ; Biofilms ; Microbial Sensitivity Tests ; Mammals ; }, abstract = {Leucine and glycine residues, at the 9th and 10th positions of helical domain of naturally occurring antimicrobial peptide (AMP), Temporin L were substituted with an unnatural amino acid, β-leucine (homovaline) to improve its serum protease stability, haemolytic/cytotoxic properties and reduce the size to some extent. The designed analogue, L9βl-TL showed either equal or improved antimicrobial activity to TL against different microorganisms including the resistant strains. Interestingly, L9βl-TL also exhibited lower haemolytic and cytotoxic activities against human red blood cells and 3T3 cells, respectively. Moreover, L9βl-TL showed antibacterial activity in presence of 25% (v/v) human serum and showed resistance against proteolytic cleavage in presence of it that suggested the serum protease stability of the TL-analogue. L9βl-TL exhibited un-ordered secondary structures in both bacterial and mammalian membrane mimetic lipid vesicles as compared to the helical structures of TL in these environments. However, tryptophan fluorescence studies demonstrated more selective interaction of L9βl-TL with bacterial membrane mimetic lipid vesicles in comparison to non-selective interactions of TL with both kinds of lipid vesicles. Membrane depolarization studies with live MRSA and bacterial membrane-mimetic lipid vesicles suggested a membrane-disrupting mode of action of L9βl-TL. L9βl-TL showed faster bactericidal mechanism compared to TL against MRSA. Interestingly, L9βl-TL was found as more potent than TL either in inhibiting biofilm formation or in eradicating the mature biofilm formed by MRSA. Overall, the present work demonstrates a simple and useful strategy to design of an analogue of TL, with minimal modifications while maintaining its antimicrobial activity with lesser toxicity and higher stability which could be attempted for other AMPs as well.}, } @article {pmid36869686, year = {2023}, author = {Ramezani, M and Monroe, MBB}, title = {Bacterial protease-responsive shape memory polymers for infection surveillance and biofilm inhibition in chronic wounds.}, journal = {Journal of biomedical materials research. Part A}, volume = {111}, number = {7}, pages = {921-937}, doi = {10.1002/jbm.a.37527}, pmid = {36869686}, issn = {1552-4965}, mesh = {Animals ; *Peptide Hydrolases/pharmacology ; Staphylococcus aureus ; Glutamic Acid/pharmacology ; Biofilms ; *Staphylococcal Infections/microbiology ; Mammals ; }, abstract = {Chronic wound healing is often negatively impacted by infection. Efficient infection assessment is crucial for effective treatment, and biofilm inhibition could improve treatment efficacy. To that end, we developed a bacterial protease-responsive shape memory polymer based on a segmented polyurethane with incorporated poly(glutamic acid) peptide (PU-Pep). Poly(glutamic acid) degrades in response to bacterial proteases to trigger shape recovery of PU-Pep films that are programmed into a secondary shape. These materials have transition temperatures well above body temperature (~60°C), which enables stable storage in temporary shapes after implantation. Synthesized polymers have high shape fixity (~74%-88%), shape recovery (~93%-95%), and cytocompatibility (~100%). Strained PU-Pep samples underwent shape recovery within ≤24 h in response to the V8 enzyme from Staphylococcus aureus (S. aureus, ~50% recovery) and multiple bacteria strains (S. aureus [~40%], Staphylococcus epidermidis [~30%], and Escherichia coli [~25%]), and they had minimal shape change in response to media controls and mammalian cells. Shape recovery of strained PU-Pep samples prevented biofilm formation on the sample surfaces, and resulting attached planktonic bacteria were vulnerable to applied treatments. PU-Pep with physically incorporated antimicrobials simultaneously prevented biofilm formation and killed isolated bacteria. PU-Pep dressings displayed visible shape change and resistance to biofilm formation in in vitro and ex vivo models. In the in vitro model, PU-Pep shape change also disrupted pre-formed biofilm structures. This novel bacterial protease-responsive biomaterial could serve as a wound dressing that changes shape specifically during bacterial colonization to alert clinicians to infection and make biofilm-associated infections easier to treat.}, } @article {pmid36869500, year = {2023}, author = {Lake, FB and van Overbeek, LS and Baars, JJP and Abee, T and den Besten, HMW}, title = {Variability in growth and biofilm formation of Listeria monocytogenes in Agaricus bisporus mushroom products.}, journal = {Food research international (Ottawa, Ont.)}, volume = {165}, number = {}, pages = {112488}, doi = {10.1016/j.foodres.2023.112488}, pmid = {36869500}, issn = {1873-7145}, mesh = {Humans ; *Listeria monocytogenes ; *Agaricus ; Mannitol ; Biofilms ; }, abstract = {Foods and food production environments can be contaminated with Listeria monocytogenes and may support growth of this foodborne pathogen. This study aims to characterize the growth and biofilm formation of sixteen L. monocytogenes strains, isolated from mushroom production and processing environments, in filter-sterilized mushroom medium. Strain performance was compared to twelve L. monocytogenes strains isolated from other sources including food and human isolates. All twenty-eight L. monocytogenes strains showed rather similar growth performance at 20 °C in mushroom medium, and also significant biofilm formation was observed for all strains. HPLC analysis revealed the presence of mannitol, trehalose, glucose, fructose and glycerol, that were all metabolized by L. monocytogenes, except mannitol, in line with the inability of L. monocytogenes to metabolize this carbohydrate. Additionally, the growing behavior of L. monocytogenes was tested on whole, sliced and smashed mushroom products to quantify performance in the presence of product-associated microbiota. A significant increase of L. monocytogenes was observed with higher increase of counts when the mushroom products were more damaged, even with the presence of high background microbiota counts. This study demonstrated that L. monocytogenes grows well in mushroom products, even when the background microbiota is high, highlighting the importance to control (re)contamination of mushrooms.}, } @article {pmid36867905, year = {2023}, author = {Deng, Y and Yang, G and Lens, PNL and He, Y and Qie, L and Shen, X and Chen, J and Cheng, Z and Chen, D}, title = {Enhanced removal of mixed VOCs with different hydrophobicities by Tween 20 in a biotrickling filter: Kinetic analysis and biofilm characteristics.}, journal = {Journal of hazardous materials}, volume = {450}, number = {}, pages = {131063}, doi = {10.1016/j.jhazmat.2023.131063}, pmid = {36867905}, issn = {1873-3336}, mesh = {Bioreactors ; Polysorbates ; *Volatile Organic Compounds/analysis ; Kinetics ; Extracellular Polymeric Substance Matrix/chemistry ; *Air Pollutants/analysis ; Filtration ; Biofilms ; Hydrophobic and Hydrophilic Interactions ; Biodegradation, Environmental ; }, abstract = {Mass transfer limitation usually causes the poor performance of biotrickling filters (BTFs) for the treatment of hydrophobic volatile organic compounds (VOCs) during long-term operation. In this study, two identical lab-scale BTFs were established to remove a mixture of n-hexane and dichloromethane (DCM) gases using non-ionic surfactant Tween 20 by Pseudomonas mendocina NX-1 and Methylobacterium rhodesianum H13. A low pressure drop (≤110 Pa) and a rapid biomass accumulation (17.1 mg g[-1]) were observed in the presence of Tween 20 during the startup period (30 d). The removal efficiency (RE) of n-hexane was enhanced by 15.0%- 20.5% while DCM was completely removed with the inlet concentration (IC) of 300 mg·m[-3] at different empty bed residence times in the Tween 20 added BTF. The viable cells and the relative hydrophobicity of the biofilm were increased under the action of Tween 20, which facilitated the mass transfer and enhanced the metabolic utilization of pollutants by microbes. Besides, Tween 20 addition enhanced the biofilm formation processes including the increased extracellular polymeric substance (EPS) secretion, biofilm roughness and biofilm adhesion. The kinetic model simulated the removal performance of the BTF with Tween 20 for the mixed hydrophobic VOCs, and the goodness-of-fit was above 0.9.}, } @article {pmid36865097, year = {2023}, author = {Arbour, CA and Nagar, R and Bernstein, HM and Ghosh, S and Al-Sammarraie, Y and Dorfmueller, HC and Ferguson, MAJ and Stanley-Wall, NR and Imperiali, B}, title = {Defining Early Steps in B. subtilis Biofilm Biosynthesis.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36865097}, abstract = {UNLABELLED: The Bacillus subtilis extracellular biofilm matrix includes an exopolysaccharide that is critical for the architecture and function of the community. To date, our understanding of the biosynthetic machinery and the molecular composition of the exopolysaccharide of B. subtilis remains unclear and incomplete. This report presents synergistic biochemical and genetic studies built from a foundation of comparative sequence analyses targeted at elucidating the activities of the first two membrane-committed steps in the exopolysaccharide biosynthetic pathway. By taking this approach, we determined the nucleotide sugar donor and lipid-linked acceptor substrates for the first two enzymes in the B. subtilis biofilm exopolysaccharide biosynthetic pathway. EpsL catalyzes the first phosphoglycosyl transferase step using UDP-di- N -acetyl bacillosamine as phospho-sugar donor. EpsD is a GT-B fold glycosyl transferase that facilitates the second step in the pathway that utilizes the product of EpsL as an acceptor substrate and UDP- N -acetyl glucosamine as the sugar donor. Thus, the study defines the first two monosaccharides at the reducing end of the growing exopolysaccharide unit. In doing so we provide the first evidence of the presence of bacillosamine in an exopolysaccharide synthesized by a Gram-positive bacterium.

IMPORTANCE: Biofilms are the communal way of life that microbes adopt to increase survival. Key to our ability to systematically promote or ablate biofilm formation is a detailed understanding of the biofilm matrix macromolecules. Here we identify the first two essential steps in the Bacillus subtilis biofilm matrix exopolysaccharide synthesis pathway. Together our studies and approaches provide the foundation for the sequential characterization of the steps in exopolysaccharide biosynthesis, using prior steps to enable chemoenzymatic synthesis of the undecaprenol diphosphate-linked glycan substrates.}, } @article {pmid36864390, year = {2023}, author = {Asadi, S and Nayeri-Fasaei, B and Zahraei-Salehi, T and Yahya-Rayat, R and Shams, N and Sharifi, A}, title = {Antibacterial and anti-biofilm properties of carvacrol alone and in combination with cefixime against Escherichia coli.}, journal = {BMC microbiology}, volume = {23}, number = {1}, pages = {55}, pmid = {36864390}, issn = {1471-2180}, mesh = {Cefixime ; *Escherichia coli ; *Anti-Bacterial Agents/pharmacology ; Cymenes/pharmacology ; }, abstract = {BACKGROUND: Plant-derived compounds can be used as antimicrobial agents in medicines and as food preservatives. These compounds can be applied along with other antimicrobial agents to strengthen the effect and/or reduce the required treatment dose.

RESULTS: In the present study, the antibacterial, anti-biofilm and quorum sensing inhibitory activity of carvacrol alone and in combination with the antibiotic cefixime against Escherichia coli was investigated. The MIC and MBC values for carvacrol were 250 μg/mL. In the checkerboard test, carvacrol showed a synergistic interaction with cefixime against E. coli (FIC index = 0.5). Carvacrol and cefixime significantly inhibited biofilm formation at MIC/2 (125 and 62.5 μg/mL), MIC/4 (62.5 and 31.25 μg/mL) and MIC/8 (31.25 and 15.625 μg/mL) for carvacrol and cefixime, respectively. The antibacterial and anti-biofilm potential effect of carvacrol confirmed by the scanning electron microscopy. Real-time quantitative reverse transcription PCR revealed significant down-regulation of the luxS and pfs genes following treatment with a MIC/2 (125 μg/mL) concentration of carvacrol alone and of only pfs gene following treatment with MIC/2 of carvacrol in combination with MIC/2 of cefixime (p < 0.05).

CONCLUSIONS: Because of the significant antibacterial and anti-biofilm activity of carvacrol, the present study examines this agent as an antibacterial drug of natural origin. The results indicate that in this study the best antibacterial and anti-biofilm properties are for the combined use of cefixime and carvacrol.}, } @article {pmid36864092, year = {2023}, author = {Frenkel, A and Zecharia, E and Gómez-Pérez, D and Sendersky, E and Yegorov, Y and Jacob, A and Benichou, JIC and Stierhof, YD and Parnasa, R and Golden, SS and Kemen, E and Schwarz, R}, title = {Cell specialization in cyanobacterial biofilm development revealed by expression of a cell-surface and extracellular matrix protein.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {10}, pmid = {36864092}, issn = {2055-5008}, mesh = {*Extracellular Matrix Proteins/genetics ; *Biofilms ; Extracellular Polymeric Substance Matrix ; Quorum Sensing ; Amyloidogenic Proteins ; }, abstract = {Cyanobacterial biofilms are ubiquitous and play important roles in diverse environments, yet, understanding of the processes underlying the development of these aggregates is just emerging. Here we report cell specialization in formation of Synechococcus elongatus PCC 7942 biofilms-a hitherto unknown characteristic of cyanobacterial social behavior. We show that only a quarter of the cell population expresses at high levels the four-gene ebfG-operon that is required for biofilm formation. Almost all cells, however, are assembled in the biofilm. Detailed characterization of EbfG4 encoded by this operon revealed cell-surface localization as well as its presence in the biofilm matrix. Moreover, EbfG1-3 were shown to form amyloid structures such as fibrils and are thus likely to contribute to the matrix structure. These data suggest a beneficial 'division of labor' during biofilm formation where only some of the cells allocate resources to produce matrix proteins-'public goods' that support robust biofilm development by the majority of the cells. In addition, previous studies revealed the operation of a self-suppression mechanism that depends on an extracellular inhibitor, which supresses transcription of the ebfG-operon. Here we revealed inhibitor activity at an early growth stage and its gradual accumulation along the exponential growth phase in correlation with cell density. Data, however, do not support a threshold-like phenomenon known for quorum-sensing in heterotrophs. Together, data presented here demonstrate cell specialization and imply density-dependent regulation thereby providing deep insights into cyanobacterial communal behavior.}, } @article {pmid36862938, year = {2023}, author = {Brezhnev, A and Tang, FK and Kwan, CS and Basabrain, MS and Tsoi, JKH and Matinlinna, JP and Neelakantan, P and Leung, KC}, title = {One-Pot Preparation of Cetylpyridinium Chloride-Containing Nanoparticles for Biofilm Eradication.}, journal = {ACS applied bio materials}, volume = {6}, number = {3}, pages = {1221-1230}, pmid = {36862938}, issn = {2576-6422}, mesh = {Cetylpyridinium/pharmacology ; *Anti-Infective Agents, Local/pharmacology ; *Nanoparticles ; Biofilms ; Streptococcus mutans ; }, abstract = {Quaternary ammonium compounds (QACs) have been widely used due to their excellent antimicrobial activity. However, using the technology where nanomaterials are employed as drug carriers to deliver QAC drugs has not been fully explored. In this study, mesoporous silica nanoparticles (MSNs) with short rod morphology were synthesized in a one-pot reaction using an antiseptic drug cetylpyridinium chloride (CPC). CPC-MSN were characterized via various methods and tested against three bacterial species (Streptococcus mutans, Actinomyces naeslundii, and Enterococcus faecalis), which are associated with oral infections, caries, and endodontic pathology. The nanoparticle delivery system used in this study prolonged the release of CPC. The manufactured CPC-MSN effectively killed the tested bacteria within the biofilm, and their size allowed them to penetrate into dentinal tubules. This CPC-MSN nanoparticle delivery system demonstrates potential for applications in dental materials.}, } @article {pmid36862127, year = {2023}, author = {Ran, W and Yue, Y and Long, F and Zhong, K and Bai, J and Xiao, Y and Bu, Q and Huang, Y and Wu, Y and Gao, H}, title = {Antibacterial Mechanism of 2R,3R-Dihydromyricetin Against Staphylococcus aureus: Deciphering Inhibitory Effect on Biofilm and Virulence Based on Transcriptomic and Proteomic Analyses.}, journal = {Foodborne pathogens and disease}, volume = {20}, number = {3}, pages = {90-99}, doi = {10.1089/fpd.2022.0075}, pmid = {36862127}, issn = {1556-7125}, mesh = {Humans ; *Staphylococcus aureus/genetics ; Virulence ; Proteomics ; Transcriptome ; Biofilms ; Membrane Proteins/genetics ; Anti-Bacterial Agents/pharmacology ; *Staphylococcal Infections ; }, abstract = {Staphylococcus aureus is a major foodborne pathogen that leads to various diseases due to its biofilm and virulence factors. This study aimed to investigate the inhibitory effect of 2R,3R-dihydromyricetin (DMY), a natural flavonoid compound, on the biofilm formation and virulence of S. aureus, and to explore the mode of action using transcriptomic and proteomic analyses. Microscopic observation revealed that DMY could remarkably inhibit the biofilm formation by S. aureus, leading to a collapse on the biofilm architecture and a decrease in viability of biofilm cell. Moreover, the hemolytic activity of S. aureus was reduced to 32.7% after treatment with subinhibitory concentration of DMY (p < 0.01). Bioinformation analysis based on RNA-sequencing and proteomic profiling revealed that DMY induced 262 differentially expressed genes and 669 differentially expressed proteins (p < 0.05). Many downregulated genes and proteins related to surface proteins were involved in biofilm formation, including clumping factor A (ClfA), iron-regulated surface determinants (IsdA, IsdB, and IsdC), fibrinogen-binding proteins (FnbA, FnbB), and serine protease. Meanwhile, DMY regulated a wide range of genes and proteins enriched in bacterial pathogenesis, cell envelope, amino acid metabolism, purine and pyrimidine metabolism, and pyruvate metabolism. These findings suggest that DMY targets S. aureus through multifarious mechanisms, and especially prompt that interference of surface proteins in cell envelope would lead to attenuation of biofilm and virulence.}, } @article {pmid36860488, year = {2023}, author = {Poon, Y and Hui, M}, title = {Inhibitory effect of lactobacilli supernatants on biofilm and filamentation of Candida albicans, Candida tropicalis, and Candida parapsilosis.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1105949}, pmid = {36860488}, issn = {1664-302X}, abstract = {INTRODUCTION: Probiotic Lactobacillus strains had been investigated for the potential to protect against infection caused by the major fungal pathogen of human, Candida albicans. Besides antifungal activity, lactobacilli demonstrated a promising inhibitory effect on biofilm formation and filamentation of C. albicans. On the other hand, two commonly isolated non-albicans Candida species, C. tropicalis and C. parapsilosis, have similar characteristics in filamentation and biofilm formation with C. albicans. However, there is scant information of the effect of lactobacilli on the two species.

METHODS: In this study, biofilm inhibitory effects of L. rhamnosus ATCC 53103, L. plantarum ATCC 8014, and L. acidophilus ATCC 4356 were tested on the reference strain C. albicans SC5314 and six bloodstream isolated clinical strains, two each of C. albicans, C. tropicalis, and C. parapsilosis.

RESULTS AND DISCUSSION: Cell-free culture supernatants (CFSs) of L. rhamnosus and L. plantarum significantly inhibited in vitro biofilm growth of C. albicans and C. tropicalis. L. acidophilus, conversely, had little effect on C. albicans and C. tropicalis but was more effective on inhibiting C. parapsilosis biofilms. Neutralized L. rhamnosus CFS at pH 7 retained the inhibitory effect, suggesting that exometabolites other than lactic acid produced by the Lactobacillus strain might be accounted for the effect. Furthermore, we evaluated the inhibitory effects of L. rhamnosus and L. plantarum CFSs on the filamentation of C. albicans and C. tropicalis strains. Significantly less Candida filaments were observed after co-incubating with CFSs under hyphae-inducing conditions. Expressions of six biofilm-related genes (ALS1, ALS3, BCR1, EFG1, TEC1, and UME6 in C. albicans and corresponding orthologs in C. tropicalis) in biofilms co-incubated with CFSs were analyzed using quantitative real-time PCR. When compared to untreated control, the expressions of ALS1, ALS3, EFG1, and TEC1 genes were downregulated in C. albicans biofilm. In C. tropicalis biofilms, ALS3 and UME6 were downregulated while TEC1 was upregulated. Taken together, the L. rhamnosus and L. plantarum strains demonstrated an inhibitory effect, which is likely mediated by the metabolites secreted into culture medium, on filamentation and biofilm formation of C. albicans and C. tropicalis. Our finding suggested an alternative to antifungals for controlling Candida biofilm.}, } @article {pmid36859622, year = {2023}, author = {Sasaki, H and Kurakado, S and Matsumoto, Y and Yoshino, Y and Sugita, T and Koyama, K and Kinoshita, K}, title = {Enniatins from a marine-derived fungus Fusarium sp. inhibit biofilm formation by the pathogenic fungus Candida albicans.}, journal = {Journal of natural medicines}, volume = {77}, number = {3}, pages = {455-463}, pmid = {36859622}, issn = {1861-0293}, mesh = {Humans ; Candida albicans/genetics ; Antifungal Agents/pharmacology ; *Fusarium ; *Candidemia ; Biofilms ; }, abstract = {Candidemia is a life-threatening disease common in immunocompromised patients, and is generally caused by the pathogenic fungus Candida albicans. C. albicans can change morphology from yeast to hyphae, forming biofilms on medical devices. Biofilm formation contributes to the virulence and drug tolerance of C. albicans, and thus compounds that suppress this morphological change and biofilm formation are effective for treating and preventing candidemia. Marine organisms produce biologically active and structurally diverse secondary metabolites that are promising lead compounds for treating numerous diseases. In this study, we explored marine-derived fungus metabolites that can inhibit morphological change and biofilm formation by C. albicans. Enniatin B (1), B1 (2), A1 (3), D (4), and E (5), visoltricin (6), ergosterol peroxide (7), 9,11-dehydroergosterol peroxide (8), and 3β,5α,9α-trihydroxyergosta-7,22-dien-6-one (9) were isolated from the marine-derived fungus Fusarium sp. Compounds 1-5 and 8 exhibited inhibitory activity against hyphal formation by C. albicans, and compounds 1-3 and 8 inhibited biofilm formation by C. albicans. Furthermore, compounds 1-3 decreased cell surface hydrophobicity and expression of the hypha-specific gene HWP1 in C. albicans. Compound 1 was obtained in the highest yield. An in vivo evaluation system using silkworms pierced with polyurethane fibers (a medical device substrate) showed that compound 1 inhibited biofilm formation by C. albicans in vivo. These results indicate that enniatins could be lead compounds for therapeutic agents for biofilm infections by C. albicans.}, } @article {pmid36858631, year = {2023}, author = {Yamane, K and Niki, M and Tsubouchi, T and Watanabe, T and Asai, K and Oinuma, KI and Sakiyama, A and Saren, C and Matsumoto, Y and Makimura, K and Kaneko, Y and Kawaguchi, T}, title = {A Culture Supernatant from an Actinomycete sp. Affects Biofilm Formation and Virulence Expression of Candida auris.}, journal = {Medical mycology journal}, volume = {64}, number = {1}, pages = {7-17}, doi = {10.3314/mmj.22-00026}, pmid = {36858631}, issn = {1882-0476}, mesh = {Virulence ; *Actinobacteria ; Candida auris ; Fluconazole ; Biofilms ; }, abstract = {The multidrug-resistant pathogen Candida auris is characterized by its aggregation under certain conditions, which affects its biofilm formation, drug susceptibility, and pathogenicity. Although the innate tendency to aggregate depends on the strain, the mechanism regulating C. auris aggregation remains unclear. We found that the culture supernatant from one of the 95 Actinomyces strains isolated from a deep-sea environment (IMAs2016D-66) inhibited C. auris aggregation. The cells grown in the presence of IMAs2016D-66 exhibited reduced hydrophobicity, biofilm formation, and enhanced proteolytic activity. In addition, the efflux pump activity of the fluconazole-resistant C. auris strain LSEM 3673 was stimulated by IMAs2016D-66, whereas no significant change was observed in the fluconazole-susceptible strain LSEM 0643. As the relationship between aggregative tendency and virulence in C. auris is still unclear, IMAs2016D-66 can serve as a tool for investigating regulatory mechanisms of phenotype switching and virulence expression of C. auris. Understanding of phenotype switching may help us not only to understand the pathogenicity of C. auris, but also to design new drugs that target the molecules regulating virulence factors.}, } @article {pmid36855815, year = {2023}, author = {Singha, R and Aggarwal, R and Sanyal, K}, title = {Negative regulation of biofilm development by the CUG-Ser1 clade-specific histone H3 variant is dependent on the canonical histone chaperone CAF-1 complex in Candida albicans.}, journal = {Molecular microbiology}, volume = {119}, number = {5}, pages = {574-585}, doi = {10.1111/mmi.15050}, pmid = {36855815}, issn = {1365-2958}, mesh = {Animals ; *Histones/genetics/metabolism ; *Candida albicans/genetics/metabolism ; Histone Chaperones/genetics/metabolism ; Chromatin ; Chromatin Assembly Factor-1/chemistry/genetics/metabolism ; Molecular Chaperones/genetics/metabolism ; Biofilms ; Mammals/genetics/metabolism ; }, abstract = {The CUG-Ser1 clade-specific histone H3 variant (H3V[CTG]) has been reported to be a negative regulator of planktonic to biofilm growth transition in Candida albicans. The preferential binding of H3V[CTG] at the biofilm gene promoters makes chromatin repressive for the biofilm mode of growth. The two evolutionarily conserved chaperone complexes involved in incorporating histone H3 are CAF-1 and HIRA. In this study, we sought to identify the chaperone complex(es) involved in loading H3V[CTG] . We demonstrate that C. albicans cells lacking either Cac1 or Cac2 subunit of the CAF-1 chaperone complex, exhibit a hyper-filamentation phenotype on solid surfaces and form more robust biofilms than wild-type cells, thereby mimicking the phenotype of the H3V[CTG] null mutant. None of the subunits of the HIRA chaperone complex shows any significant difference in biofilm growth as compared to the wild type. The occupancy of H3V[CTG] is found to be significantly reduced at the promoters of biofilm genes in the absence of CAF-1 subunits. Hence, we provide evidence that CAF-1, a chaperone known to load canonical histone H3 in mammalian cells, is involved in chaperoning of variant histone H3V[CTG] at the biofilm gene promoters in C. albicans. Our findings also illustrate the acquisition of an unconventional role of the CAF-1 chaperone complex in morphogenesis in C. albicans.}, } @article {pmid36855334, year = {2023}, author = {Chan, RK and Nuutila, K and Mathew-Steiner, SS and Diaz, V and Anselmo, K and Batchinsky, M and Carlsson, A and Ghosh, N and Sen, CK and Roy, S}, title = {A Prospective, Randomized, Controlled Study to Evaluate the Effectiveness of a Fabric-Based Wireless Electroceutical Dressing Compared to Standard-of-Care Treatment Against Acute Trauma and Burn Wound Biofilm Infection.}, journal = {Advances in wound care}, volume = {}, number = {}, pages = {}, doi = {10.1089/wound.2023.0007}, pmid = {36855334}, issn = {2162-1918}, abstract = {Objective: Despite advances in the use of topical and parenteral antimicrobial therapy and the practice of early tangential burn wound excision to manage bacterial load, 60% of the mortality from burns is attributed to bacterial biofilm infection. A low electric field (∼1 V) generated by the novel FDA-cleared wireless electroceutical dressing (WED) was previously shown to significantly prevent and disrupt burn biofilm infection in preclinical studies. Based on this observation, the purpose of this clinical trial was to evaluate the efficacy of the WED dressing powered by a silver-zinc electrocouple in the prevention and disruption of biofilm infection. Approach: A prospective, randomized, controlled, single-center clinical trial was performed to evaluate the efficacy of the WED compared with standard-of-care (SoC) dressing to treat biofilms. Burn wounds were randomized to receive either SoC or WED. Biopsies were collected on days 0 and 7 for histology, scanning electron microscopy (SEM) examination of biofilm, and for quantitative bacteriological analyses. Results: In total, 38 subjects were enrolled in the study. In 52% of the WED-treated wounds, little to no biofilm could be detected by SEM. WED significantly lowered or prevented increase of biofilm in all wounds compared with the pair-matched SoC-treated wounds. Innovation: WED is a simple, easy, and rapid method to protect the wound while also inhibiting infection. It is activated by a moist environment and the electrical field induces transient and micromolar amounts of superoxide anion radicals that will prevent bacterial growth. Conclusion: WED decreased biofilm infection better compared with SoC. The study was registered in clinicaltrials.gov as NCT04079998.}, } @article {pmid36854956, year = {2023}, author = {Ivanova, LA and Egorov, VV and Zabrodskaya, YA and Shaldzhyan, AA and Baranchikov, AY and Tsvigun, NV and Lykholay, AN and Yapryntsev, AD and Lebedev, DV and Kulminskaya, AA}, title = {Matrix is everywhere: extracellular DNA is a link between biofilm and mineralization in Bacillus cereus planktonic lifestyle.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {9}, pmid = {36854956}, issn = {2055-5008}, mesh = {Male ; Humans ; *Bacillus cereus/genetics ; *Semen ; Biofilms ; Calcium Carbonate ; DNA ; }, abstract = {To date, the mechanisms of biomineralization induced by bacterial cells in the context of biofilm formation remain the subject of intensive studies. In this study, we analyzed the influence of the medium components on the induction of CaCO3 precipitation by the Bacillus cereus cells and composition of the extracellular matrix (ECM) formed in the submerged culture. While the accumulation of extracellular polysaccharides and amyloids appeared to be independent of the presence of calcium and urea during the growth, the accumulation of extracellular DNA (eDNA), as well as precipitation of calcium carbonate, required the presence of both ingredients in the medium. Removal of eDNA, which was sensitive to treatment by DNase, did not affect other matrix components but resulted in disruption of cell network formation and a sixfold decrease in the precipitate yield. An experiment with a cell-free system confirmed the acceleration of mineral formation after the addition of exogenous salmon sperm DNA. The observed pathway for the formation of CaCO3 minerals in B. cereus planktonic culture included a production of exopolysaccharides and negatively charged eDNA lattice promoting local Ca[2+] supersaturation, which, together with an increase in the concentration of carbonate ions due to pH rise, resulted in the formation of an insoluble precipitate of calcium carbonate. Precipitation of amorphous CaCO3 on eDNA matrix was followed by crystal formation via the ACC-vaterite-calcite/aragonite pathway and further formation of larger mineral aggregates in complex with extracellular polymeric substances. Taken together, our data showed that DNA in extracellular matrix is an essential factor for triggering the biomineralization in B. cereus planktonic culture.}, } @article {pmid36853819, year = {2023}, author = {Morselli, S and Salvo, M and Foschi, C and Lazzarotto, T and Ambretti, S and Marangoni, A}, title = {Characterization of Gardnerella vaginalis isolates: correlations among clades, biofilm formation and cytokine stimulation.}, journal = {The new microbiologica}, volume = {46}, number = {1}, pages = {56-59}, pmid = {36853819}, issn = {1121-7138}, mesh = {Humans ; Female ; *Gardnerella vaginalis/genetics ; *Metronidazole ; HeLa Cells ; Biofilms ; Cytokines ; }, abstract = {We characterized 61 Gardnerella vaginalis (GV) strains isolated from women with bacterial vaginosis. GV clade 1 was the most commonly found (52.5%), followed by clade 4 (36.1%). All the strains were susceptible to ampicillin and clindamycin, whereas 96.7% and 6.6% of strains showed metronidazole and tetracycline resistance, respectively. Isolates within clade 4 tended to possess the highest ability to form biofilm. Strains resistant to metronidazole and tetracycline were all intermediate or high biofilm producers. All GV clades significantly upregulated the production of pro-inflammatory cytokines by HeLa cells, especially IL-8 and IL-6. Clade 4 induced a significantly higher production of IL-1β compared to other clades.}, } @article {pmid36853055, year = {2023}, author = {Bianchini Fulindi, R and Domingues Rodrigues, J and Lemos Barbosa, TW and Goncalves Garcia, AD and de Almeida La Porta, F and Pratavieira, S and Chiavacci, LA and Pessoa Araújo Junior, J and da Costa, PI and Martinez, LR}, title = {Zinc-Based Nanoparticles Reduce Bacterial Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0483122}, pmid = {36853055}, issn = {2165-0497}, support = {R01 AI145559/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilm formation is important for microbial survival in hostile environments and a phenotype that provides microorganisms with antimicrobial resistance. Zinc oxide (ZnO) and Zinc sulfide (ZnS) nanoparticles (NPs) present potential antimicrobial properties for biomedical and food industry applications. Here, we aimed to analyze, for the first time, the bactericidal and antibiofilm activity of ZnS NPs against Staphylococcus aureus, Klebsiella oxytoca, and Pseudomonas aeruginosa, all medically important bacteria in developed countries. We compared ZnS NPs antimicrobial activity to ZnO NPs, which have been extensively studied. Using the colorimetric XTT reduction assay to observe the metabolic activity of bacterial cells and the crystal violet assay to measure biofilm mass, we demonstrated that ZnS and ZnO had similar efficacy in killing planktonic bacterial cells and reducing biofilm formation, with S. aureus being more susceptible to both therapeutics than K. oxytoca and P. aeruginosa. Crystal violet staining and confocal microscopy validated that Zn NPs inhibit biofilm formation and cause architectural damage. Our findings provide proof of principle that ZnS NPs have antibiofilm activity, and can be potentially used in medical and food industry applications, such as treatment of wound infections or package coating for food preservation. IMPORTANCE Zinc (Zn)-based nanoparticles (NPs) can be potentially used in medical and food preservation applications. As proof of principle, we investigated the bactericidal and antibiofilm activity of zinc oxide (ZnO) and zinc sulfide (ZnS) NPs against medically important bacteria. Zn-based NPs were similarly effective in killing planktonic and biofilm-associated Staphylococcus aureus, Klebsiella oxytoca, and Pseudomonas aeruginosa cells. However, S. aureus was more susceptible to these investigational therapeutics. Although further studies are warranted, our findings suggest the possibility of future use of Zn-based NPs in the treatment of skin infections or preservation of food.}, } @article {pmid36850031, year = {2023}, author = {Li, Q and Liu, Q and Wang, Z and Zhang, X and Ma, R and Hu, X and Mei, J and Su, Z and Zhu, W and Zhu, C}, title = {Biofilm Homeostasis Interference Therapy via [1] O2 -Sensitized Hyperthermia and Immune Microenvironment Re-Rousing for Biofilm-Associated Infections Elimination.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {19}, number = {22}, pages = {e2300592}, doi = {10.1002/smll.202300592}, pmid = {36850031}, issn = {1613-6829}, mesh = {*Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Phototherapy ; Prostheses and Implants ; *Hyperthermia, Induced/methods ; }, abstract = {The recurrence of biofilm-associated infections (BAIs) remains high after implant-associated surgery. Biofilms on the implant surface reportedly shelter bacteria from antibiotics and evade innate immune defenses. Moreover, little is currently known about eliminating residual bacteria that can induce biofilm reinfection. Herein, novel "interference-regulation strategy" based on bovine serum albumin-iridium oxide nanoparticles (BIONPs) as biofilm homeostasis interrupter and immunomodulator via singlet oxygen ([1] O2)-sensitized mild hyperthermia for combating BAIs is reported. The catalase-like BIONPs convert abundant H2 O2 inside the biofilm-microenvironment (BME) to sufficient oxygen gas (O2), which can efficiently enhance the generation of [1] O2 under near-infrared irradiation. The [1] O2 -induced biofilm homeostasis disturbance (e.g., sigB, groEL, agr-A, icaD, eDNA) can disrupt the sophisticated defense system of biofilm, further enhancing the sensitivity of biofilms to mild hyperthermia. Moreover, the mild hyperthermia-induced bacterial membrane disintegration results in protein leakage and [1] O2 penetration to kill bacteria inside the biofilm. Subsequently, BIONPs-induced immunosuppressive microenvironment re-rousing successfully re-polarizes macrophages to pro-inflammatory M1 phenotype in vivo to devour residual biofilm and prevent biofilm reconstruction. Collectively, this [1] O2 -sensitized mild hyperthermia can yield great refractory BAIs treatment via biofilm homeostasis interference, mild-hyperthermia, and immunotherapy, providing a novel and effective anti-biofilm strategy.}, } @article {pmid36849163, year = {2023}, author = {Xiong, Q and Qu, J and Zhao, R and Chen, Y and Li, Y and Xu, W and Pan, B and Jin, P and Zheng, Z}, title = {Fabrication of a novel polyurethane foam-alginate-zeolite hydrogel and subsequent KSND bacteria encapsulation: evidence of accelerated biofilm colonization and enhanced nitrogen removal efficiency.}, journal = {Letters in applied microbiology}, volume = {76}, number = {3}, pages = {}, doi = {10.1093/lambio/ovac054}, pmid = {36849163}, issn = {1472-765X}, support = {2020C02009//Key Research and Development Project of Jiangsu Province/ ; }, mesh = {*Hydrogels ; Denitrification ; Wastewater ; *Zeolites ; Bacteria ; Alginates ; Biofilms ; Nitrogen ; }, abstract = {Biofilms are used widely to remove nitrogen from wastewater; however, most biofilm carriers (i.e. polyurethane foam, PUF) are hydrophobic organic materials with millimetre-scale apertures, ineffective attachment, and unstable colonization of microorganisms. To address these limitations, hydrophilic sodium alginate (SA) mixed with zeolite powder (Zeo) was cross-linked in PUF to form a micro-scale hydrogel (PAS) with a well-organized and reticular cellular structure. Scanning electron microscopy revealed that immobilized cells were entrapped in the interior of hydrogel filaments and rapidly formed a stable biofilm on the surface. The biofilm generated was 10.3-fold greater than the film developed on PUF. Kinetics and isotherm studies revealed that the as-developed carrier, because of the presence of Zeo, effectively improved the adsorption of NH4+-N by 53%. The PAS carrier achieved total nitrogen removal in excess of 86% for low carbon-to-nitrogen ratio wastewater treated for 30 d, indicating that this novel modification-encapsulation technology has potential for wastewater treatment.}, } @article {pmid36848732, year = {2023}, author = {Brunswick, P and Blajkevitch, O and Filewood, T and Kent, E and Drever, MC and Elner, RW and Shang, D}, title = {Long chain fatty acids analysis of intertidal biofilm by direct injection liquid chromatography time of flight mass spectrometry.}, journal = {Journal of chromatography. A}, volume = {1693}, number = {}, pages = {463870}, doi = {10.1016/j.chroma.2023.463870}, pmid = {36848732}, issn = {1873-3778}, mesh = {Animals ; *Fatty Acids/analysis ; *Fatty Acids, Unsaturated/analysis ; Mass Spectrometry/methods ; Methanol ; Chromatography, Liquid/methods ; }, abstract = {The critical importance of mono- and polyunsaturated fatty acids (FAs) in a variety of biological functions, including animal nutrition and as an environmental stress monitor, is well recognized. However, while methods exist for monitoring of fatty acids, few are specific either to the profile of a microphytobenthos matrix or practical in application to multiple, diverse intertidal biofilm sample sets. In the current study, a sensitive liquid chromatography (LC) quadrupole time of flight mass spectrometry (QTOF) method was developed for the quantitative analysis of 31 FAs specific to intertidal biofilm, a thin mucilaginous layer of microalgae, bacteria, and other organisms on the surface of coastal mudflats, which provide a rich source of FAs for migratory birds. Preliminary screening of diverse biofilm samples collected from shorebird feeding grounds highlighted eight saturated (SFA), seven monounsaturated (MUFA), and sixteen polyunsaturated FAs (PUFA) that were selected for analysis. Improved method detection limits in the range 0.3-2.6 ngmL[-1] were achieved, excepting for stearic acid at 10.6 ngmL[-1]. These excellent results were obtained without use of complex sample extraction and clean-up procedures undertaken by other published methods. An alkaline matrix of dilute aqueous ammonium hydroxide with methanol was shown to be selective for extraction and stability of the more hydrophilic fatty acid components. The direct injection method showed excellent precision and accuracy both during validation and application to hundreds of real-world intertidal biofilm samples from the Fraser River estuary (British Columbia, Canada) and other areas of the region frequented by shoreline birds.}, } @article {pmid36847907, year = {2023}, author = {Fatima, T and Fatima, Z and Hameed, S}, title = {Abrogation of efflux pump activity, biofilm formation, and immune escape by candidacidal geraniol in emerging superbug, Candida auris.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {36847907}, issn = {1618-1905}, abstract = {During the last decade, Candida auris emerged as a threatening human fungal pathogen that notably caused outbreaks around the globe with high mortality. Considering C. auris species as newly discovered fungi, the evolutionary features remain elusive. The antifungal resistance which is a norm in C. auris underlines the need for innovative therapeutic options. ATP Binding Cassette (ABC) superfamily efflux pumps overexpression and biofilms are known to be major contributors to multidrug resistance (MDR) in C. auris. Therefore, herein, we investigated the antifungal potential of geraniol (Ger) as a promising natural compound in the fight against MDR C. auris. Our experiments proved that Ger was fungicidal in nature and impaired rhodamine 6G (R6G) efflux, confirming the specific effect on ABC transporters. Kinetic studies unravelled the competitive mode of inhibition by Ger for R6G efflux since the apparent Km increased with no change in Vmax value. Mechanistic insights also revealed that Ger depleted ergosterol content in C. auris. Furthermore, Ger led to inhibition in biofilm formation as evident from crystal violet staining, biofilm metabolic and biomass measurements. Additionally, enhanced survival of Caenorhabditis elegans model after C. auris infection demonstrated the in vivo efficacy of Ger. Lastly, the in vivo efficacy was confirmed from a THP-1 cell line model which depicted enhanced macrophage-mediated killing in the presence of Ger. Modulation of C. auris efflux pump activity and biofilm formation by Ger represents a promising approach to combat MDR. Together, this study demonstrated the potential therapeutic insights of Ger as a promising addition to the antifungal armamentarium required to treat emerging and resistant C. auris.}, } @article {pmid36847713, year = {2023}, author = {Bravo, E and Serrano, B and Ribeiro-Vidal, H and Virto, L and Sánchez, IS and Herrera, D and Sanz, M}, title = {Biofilm formation on dental implants with a hybrid surface microtopography: An in vitro study in a validated multispecies dynamic biofilm model.}, journal = {Clinical oral implants research}, volume = {34}, number = {5}, pages = {475-485}, doi = {10.1111/clr.14054}, pmid = {36847713}, issn = {1600-0501}, support = {//Mozograu/ ; }, mesh = {*Dental Implants/microbiology ; Titanium/chemistry ; Surface Properties ; Biofilms ; Mouth ; Bacteria ; }, abstract = {OBJECTIVES: The objective of this study is to qualitatively and quantitatively evaluate biofilm formation on hybrid titanium implants (HS), with moderately rough and turned surface topographies.

MATERIALS AND METHODS: A validated dynamic in vitro multispecies biofilm model, based on bacterial growth under flow and shear conditions resembling the oral cavity, was used to evaluate biofilm formation on the tested implant surfaces. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to compare the biofilm structure and microbial biomass deposited on either the moderately rough or the turned surface of HS. Quantitative polymerase chain reaction (qPCR) was used to evaluate the total bacterial counts and counts of each specific bacterium in biofilms formed on implants with either the moderately rough or the turned surfaces, as in the hybrid titanium implants, after 24, 48 and 72 h. A general linear model was applied to compare the CLSM and qPCR results between the tested implant surfaces.

RESULTS: A significantly higher bacterial biomass grew on the moderately rough implant surfaces, compared to the turned surface area of HS implants (p < .05), at all incubation times, as evidenced with both CLSM and SEM. qPCR analysis also demonstrated an important increase in the total and specific bacterial counts in moderately rough surface implants at the three incubation times.

CONCLUSIONS: Implant surface topography (moderately rough versus turned) significantly influenced in vitro biofilm formation in terms of biofilm structure, bacterial biomass and quantity of the specific species selected for the model used.}, } @article {pmid36847700, year = {2023}, author = {Virto, L and Odeh, V and Garcia-Quismondo, E and Herrera, D and Palma, J and Tamimi, F and Sanz, M}, title = {Electrochemical decontamination of titanium dental implants. An in vitro biofilm model study.}, journal = {Clinical oral implants research}, volume = {34}, number = {5}, pages = {486-497}, doi = {10.1111/clr.14055}, pmid = {36847700}, issn = {1600-0501}, support = {//International Team for Implantology/ ; }, mesh = {*Dental Implants/microbiology ; Titanium/chemistry ; Decontamination ; Biofilms ; Anti-Bacterial Agents ; Bacteria ; Surface Properties ; }, abstract = {OBJECTIVES: The objective of this study is to study the effect of electrochemical treatment on biofilms developed on titanium dental implants, using a six-species in vitro model simulating subgingival oral biofilms.

MATERIALS AND METHODS: Direct electrical current (DC) of 0.75 V, 1.5 V, and 3 V (anodic polarization, oxidation processes) and of -0.75 V, -1.5 V, and -3 V (cathodic polarization, reduction processes) was applied between the working and the reference electrodes for 5 min on titanium dental implants, which have been previously inoculated with a multispecies biofilm. This electrical application consisted of a three-electrode system where the implant was the working electrode, a platinum mesh was the counter electrode, and an Ag/AgCl electrode was the reference. The effect of the electrical application on the biofilm structure and bacterial composition was evaluated by scanning electron microscopy and quantitative polymerase chain reaction. A generalized linear model was applied to study the bactericidal effect of the proposed treatment.

RESULTS: The electrochemical construct at 3 V and -3 V settings significantly reduced total bacterial counts (p < .05) from 3.15 × 10[6] to 1.85 × 10[5] and 2.92 × 10[4]  live bacteria/mL, respectively. Fusobacterium nucleatum was the most affected species in terms of reduction in concentration. The 0.75 V and -0.75 V treatments had no effect on the biofilm.

CONCLUSION: Electrochemical treatments had a bactericidal effect on this multispecies subgingival in vitro biofilm model, being the reduction more effective than the oxidative treatment.}, } @article {pmid36847543, year = {2023}, author = {Dong, J and Liu, L and Chen, L and Xiang, Y and Wang, Y and Zhao, Y}, title = {The Coexistence of Bacterial Species Restructures Biofilm Architecture and Increases Tolerance to Antimicrobial Agents.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0358122}, pmid = {36847543}, issn = {2165-0497}, abstract = {Chronic infections caused by polymicrobial biofilms are often difficult to treat effectively, partially due to the elevated tolerance of polymicrobial biofilms to antimicrobial treatments. It is known that interspecific interactions influence polymicrobial biofilm formation. However, the underlying role of the coexistence of bacterial species in polymicrobial biofilm formation is not fully understood. Here, we investigated the effect of the coexistence of Enterococcus faecalis, Escherichia coli O157:H7, and Salmonella enteritidis on triple-species biofilm formation. Our results demonstrated that the coexistence of these three species enhanced the biofilm biomass and led to restructuring of the biofilm into a tower-like architecture. Furthermore, the proportions of polysaccharides, proteins, and eDNAs in the extracellular matrix (ECM) composition of the triple-species biofilm were significantly changed compared to those in the E. faecalis mono-species biofilm. Finally, we analyzed the transcriptomic profile of E. faecalis in response to coexistence with E. coli and S. enteritidis in the triple-species biofilm. The results suggested that E. faecalis established dominance and restructured the triple-species biofilm by enhancing nutrient transport and biosynthesis of amino acids, upregulating central carbon metabolism, manipulating the microenvironment through "biological weapons," and activating versatile stress response regulators. Together, the results of this pilot study reveal the nature of E. faecalis-harboring triple-species biofilms with a static biofilm model and provide novel insights for further understanding interspecies interactions and the clinical treatment of polymicrobial biofilms. IMPORTANCE Bacterial biofilms possess distinct community properties that affect various aspects of our daily lives. In particular, biofilms exhibit increased tolerance to chemical disinfectants, antimicrobial agents, and host immune responses. Multispecies biofilms are undoubtedly the dominant form of biofilms in nature. Thus, there is a pressing need for more research directed at delineating the nature of multispecies biofilms and the effects of the properties on the development and survival of the biofilm community. Here, we address the effects of the coexistence of Enterococcus faecalis, Escherichia coli, and Salmonella enteritidis on triple-species biofilm formation with a static model. In combination with transcriptomic analyses, this pilot study explores the potential underlying mechanisms that lead to the dominance of E. faecalis in triple-species biofilms. Our findings provide novel insights into the nature of triple-species biofilms and indicate that the composition of multispecies biofilms should be a key consideration when determining antimicrobial treatments.}, } @article {pmid36847490, year = {2023}, author = {Long, DR and Penewit, K and Lo, HY and Almazan, J and Holmes, EA and Bryan, AB and Wolter, DJ and Lewis, JD and Waalkes, A and Salipante, SJ}, title = {In Vitro Selection Identifies Staphylococcus aureus Genes Influencing Biofilm Formation.}, journal = {Infection and immunity}, volume = {91}, number = {3}, pages = {e0053822}, pmid = {36847490}, issn = {1098-5522}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; K23 AR080209/AR/NIAMS NIH HHS/United States ; }, mesh = {Humans ; *Staphylococcus aureus/metabolism ; Plasmids ; Mutation ; *Staphylococcal Infections ; Biofilms ; }, abstract = {Staphylococcus aureus generates biofilms during many chronic human infections, which contributes to its growth and persistence in the host. Multiple genes and pathways necessary for S. aureus biofilm production have been identified, but knowledge is incomplete, and little is known about spontaneous mutations that increase biofilm formation as infection progresses. Here, we performed in vitro selection of four S. aureus laboratory strains (ATCC 29213, JE2, N315, and Newman) to identify mutations associated with enhanced biofilm production. Biofilm formation increased in passaged isolates from all strains, exhibiting from 1.2- to 5-fold the capacity of parental lines. Whole-genome sequencing identified nonsynonymous mutations affecting 23 candidate genes and a genomic duplication encompassing sigB. Six candidate genes significantly impacted biofilm formation as isogenic transposon knockouts: three were previously reported to impact S. aureus biofilm formation (icaR, spdC, and codY), while the remaining three (manA, narH, and fruB) were newly implicated by this study. Plasmid-mediated genetic complementation of manA, narH, and fruB transposon mutants corrected biofilm deficiencies, with high-level expression of manA and fruB further enhancing biofilm formation over basal levels. This work recognizes genes not previously identified as contributing to biofilm formation in S. aureus and reveals genetic changes able to augment biofilm production by that organism.}, } @article {pmid36846774, year = {2023}, author = {Zhang, M and Xue, X and Li, X and Wu, Q and Zhang, T and Yang, W and Hu, L and Zhou, D and Lu, R and Zhang, Y}, title = {QsvR and OpaR coordinately repress biofilm formation by Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1079653}, pmid = {36846774}, issn = {1664-302X}, abstract = {Mature biofilm formation by Vibrio parahaemolyticus requires exopolysaccharide (EPS), type IV pili, and capsular polysaccharide (CPS). Production of each is strictly regulated by various control pathways including quorum sensing (QS) and bis-(3'-5')-cyclic di-GMP (c-di-GMP). QsvR, an AraC-type regulator, integrates into the QS regulatory cascade via direct control of the transcription of the master QS regulators, AphA and OpaR. Deletion of qsvR in wild-type or opaR mutant backgrounds altered the biofilm formation by V. parahaemolyticus, suggesting that QsvR may coordinate with OpaR to control biofilm formation. Herein, we demonstrated both QsvR and OpaR repressed biofilm-associated phenotypes, c-di-GMP metabolism, and the formation of V. parahaemolyticus translucent (TR) colonies. QsvR restored the biofilm-associated phenotypic changes caused by opaR mutation, and vice versa. In addition, QsvR and OpaR worked coordinately to regulate the transcription of EPS-associated genes, type IV pili genes, CPS genes and c-di-GMP metabolism-related genes. These results demonstrated how QsvR works with the QS system to regulate biofilm formation by precisely controlling the transcription of multiple biofilm formation-associated genes in V. parahaemolyticus.}, } @article {pmid36846753, year = {2023}, author = {Li, L and Yu, T and Yuan, L and Doulgeraki, AI and Iseppi, R}, title = {Corrigendum: Editorial: Biofilm formation and quorum sensing of foodborne microorganism.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1144058}, doi = {10.3389/fmicb.2023.1144058}, pmid = {36846753}, issn = {1664-302X}, abstract = {[This corrects the article DOI: 10.3389/fmicb.2022.1107603.].}, } @article {pmid36845825, year = {2023}, author = {De Bleeckere, A and Van den Bossche, S and De Sutter, PJ and Beirens, T and Crabbé, A and Coenye, T}, title = {High throughput determination of the biofilm prevention concentration for Pseudomonas aeruginosa biofilms using a synthetic cystic fibrosis sputum medium.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100106}, pmid = {36845825}, issn = {2590-2075}, abstract = {The presence of Pseudomonas aeruginosa biofilms in cystic fibrosis (CF) patients suffering from chronic lung infections contributes to the failure of antimicrobial therapy. Conventionally, the minimal inhibitory concentration (MIC) is determined to assess the antimicrobial susceptibility of a pathogen, however this parameter fails to predict success in treating biofilm-associated infections. In the present study we developed a high throughput method to determine the antimicrobial concentration required to prevent P. aeruginosa biofilm formation, using a synthetic cystic fibrosis sputum medium (SCFM2). Biofilms were grown in SCFM2 for 24 h in the presence of antibiotics (tobramycin, ciprofloxacin or colistin), whereafter biofilms were disrupted and a resazurin staining was used to quantify the number of surviving metabolically active cells. In parallel, the content of all wells was plated to determine the number of colony forming units (CFU). Biofilm preventing concentrations (BPCs) were compared to MICs and minimal bactericidal concentrations (MBCs) determined according to EUCAST guidelines. Correlations between the resazurin-derived fluorescence and CFU counts were assessed with Kendall's Tau Rank tests. A significant correlation between fluorescence and CFU counts was observed for 9 out of 10 strains investigated, suggesting the fluorometric assay is a reliable alternative to plating for most P. aeruginosa isolates to determine biofilm susceptibility in relevant conditions. For all isolates a clear difference between MICs and BPCs of all three antibiotics was observed, with the BPCs being consistently higher than the MICs. Additionally, the extent of this difference appeared to be antibiotic-dependent. Our findings suggest that this high throughput assay could be a valuable addition to evaluate the antimicrobial susceptibility in P. aeruginosa biofilms in the context of CF.}, } @article {pmid36845188, year = {2023}, author = {Cao, LY and Liu, CG and Yang, SH and Bai, FW}, title = {Regulation of biofilm formation in Zymomonas mobilis to enhance stress tolerance by heterologous expression of pfs and luxS.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1130405}, pmid = {36845188}, issn = {2296-4185}, abstract = {Zymomonas mobilis is a potential alternative of Saccharomyces cerevisiae to produce cellulosic ethanol with strengths in cofactor balance, but its lower tolerance to inhibitors in the lignocellulosic hydrolysate restricts the application. Although biofilm can improve bacteria stress tolerance, regulating biofilm formation in Z. mobilis is still a challenge. In this work, we constructed a pathway by heterologous expressing pfs and luxS from Escherichia coli in Z. mobilis to produce AI-2 (autoinducer 2), a universal quorum-sensing signal molecule, to control cell morphology for enhancing stress tolerance. Unexpectedly, the results suggested that neither endogenous AI-2 nor exogenous AI-2 promoted biofilm formation, while heterologous expression of pfs can significantly raise biofilm. Therefore, we proposed that the main factor in assisting biofilm formation was the product accumulated due to heterologous expression of pfs, like methylated DNA. Consequently, ZM4::pfs produced more biofilm, which presented an enhanced tolerance to acetic acid. All these findings provide a novel strategy to improve the stress tolerance of Z. mobilis by enhancing biofilm formation for efficient production of lignocellulosic ethanol and other value-added chemical products.}, } @article {pmid36844532, year = {2023}, author = {Hassan, N and Farooq, U and Das, AK and Sharma, K and Mirza, MA and Fatima, S and Singh, O and Ansari, MJ and Ali, A and Iqbal, Z}, title = {In Silico Guided Nanoformulation Strategy for Circumvention of Candida albicans Biofilm for Effective Therapy of Candidal Vulvovaginitis.}, journal = {ACS omega}, volume = {8}, number = {7}, pages = {6918-6930}, pmid = {36844532}, issn = {2470-1343}, abstract = {Candidal vulvovaginitis involving multispecies of Candida and epithelium-bound biofilm poses a drug-resistant pharmacotherapeutic challenge. The present study aims for a disease-specific predominant causative organism resolution for the development of a tailored vaginal drug delivery system. The proposed work fabricates a luliconazole-loaded nanostructured lipid carrier-based transvaginal gel for combating Candida albicans biofilm and disease amelioration. The interaction and binding affinity of luliconazole against the proteins of C. albicans and biofilm were assessed using in silico tools. A systematic QbD analysis was followed to prepare the proposed nanogel using a modified melt emulsification-ultrasonication-gelling method. The DoE optimization was logically implemented to ascertain the effect of independent process variables (excipients concentration; sonication time) on dependent formulation responses (particle size; polydispersity index; entrapment efficiency). The optimized formulation was characterized for final product suitability. The surface morphology and dimensions were spherical and ≤300 nm, respectively. The flow behavior of an optimized nanogel (semisolid) was non-Newtonian similar to marketed preparation. The texture pattern of a nanogel was firm, consistent, and cohesive. The release kinetic model followed was Higuchi (nanogel) with a % cumulative drug release of 83.97 ± 0.69% in 48 h. The % cumulative drug permeated across a goat vaginal membrane was found to be 53.148 ± 0.62% in 8 h. The skin-safety profile was examined using a vaginal irritation model (in vivo) and histological assessments. The drug and proposed formulation(s) were checked against the pathogenic strains of C. albicans (vaginal clinical isolates) and in vitro established biofilms. The visualization of biofilms was done under a fluorescence microscope revealing mature, inhibited, and eradicated biofilm structures.}, } @article {pmid36842356, year = {2023}, author = {Sun, KM and Wang, J and Ju, Q and Zhao, Y and Kong, X and Yuan, C and Tian, Y}, title = {The mitigating effects of diatom-bacteria biofilm on coastal harmful algal blooms: A lab-based study concerning species-specific competition and biofilm formation.}, journal = {Journal of environmental management}, volume = {335}, number = {}, pages = {117544}, doi = {10.1016/j.jenvman.2023.117544}, pmid = {36842356}, issn = {1095-8630}, mesh = {Humans ; Harmful Algal Bloom ; *Diatoms ; Ecosystem ; *Dinoflagellida ; Phosphates ; }, abstract = {Harmful algal blooms (HABs) in coastal areas severely affected the health of ecosystem and human beings. The HABs control by biological methods, especially for biofilms, has been research hotspots in freshwater ecosystem. However, the biofilm-relating control of HABs in marine environment was very limited. In the present study, we found the population growth of two harmful algal species, Prorocentrum obtusidens Schiller (formerly P. donghaiense Lu) and Heterosigma akashiwo, were inhibited by a diatom-bacteria biofilm. The highest inhibitory rate was 79.6 ± 2.1% for P. obtusidens when co-cultured with biofilm suspension, and was 88.6 ± 5.8% for H. akashiwo when co-cultured with the biofilm filtrate without nutrient replenishment. When nitrate and phosphate were added, the inhibition rate for P. obtusidens was 72.3 ± 2.0%, but the population inhibition was not found in H. akashiwo. It suggested that P. obtusidens was mainly inhibited via interference competition, while the inhibition of H. akashiwo was resulted from exploitation competition. We further investigated the role of fatty acids for the interference competition in P. obtusidens, and found that fatty acids at their environmental-relevance concentrations can inhibit the photosynthetic capacity of P. obtusidens, but cannot inhibit the population growth. The community of biofilm shifted, and was finally dominated by the photoheterotrophic bacterium Dinoroseobacter shibae, and the diatom Fistulifera sp. with relative abundance of higher than 90%. Our study indicated that the diatom-bacteria biofilm was likely the candidate for the HABs control in marine environment. D. shibae and Fistulifera sp. were probably the effective species in the biofilm.}, } @article {pmid36841082, year = {2023}, author = {Adedoyin, FT and Sridhar, BBM and Rosenzweig, JA}, title = {Impact of metal exposure on environmentally isolated Serratia marcescens' growth, oxidative-stress resistance, biofilm formation, and proliferation in eukaryotic co-culture models.}, journal = {Ecotoxicology and environmental safety}, volume = {253}, number = {}, pages = {114677}, doi = {10.1016/j.ecoenv.2023.114677}, pmid = {36841082}, issn = {1090-2414}, mesh = {Humans ; *Serratia marcescens ; *Eukaryota ; Coculture Techniques ; Lead/toxicity ; Manganese/toxicity ; Zinc/toxicity ; Oxidative Stress ; Biofilms ; Cell Proliferation ; }, abstract = {Environmental metals can be noxious to the surrounding biota, indirectly impact freshwater habitats, and also impact microbiological communities. In this study, zinc (Zn) (55.5 mg/kg), manganese (Mn) (863.4 mg/kg) and lead (Pb) (17.5 mg/kg) levels measured in Houston watershed flood plain soil samples were higher than environmental agencies' thresholds. To investigate the effects of metal exposures, an environmentally isolated Serratia marcescens (SME), etiological agent of endocarditis and respiratory infections, and its reference strain (SMR) were exposed to Pb, Zn, and Mn, and subsequent oxidative stress responses and biofilm production were measured. Not surprisingly, SME was less sensitive to all 3 metal exposures than was SMR. Interestingly, SME produced increased biofilm and was more resistant to oxidative stress in the presence of Zn and Pb than SMR. In a 6 h lung infection model using BAES-2B cells, SME exhibited greater proliferation than SMR in all metal challenges. Similarly, in our HT29 gut infection model, SME out-proliferated SMR when challenged with Pb and Mn following the 6 h infection. Taken together, SME was better able to withstand environmental stressors than SMR, suggesting increased virulence potential of this opportunistic human pathogen.}, } @article {pmid36839796, year = {2023}, author = {Aleksandrova, YI and Shurpik, DN and Nazmutdinova, VA and Mostovaya, OA and Subakaeva, EV and Sokolova, EA and Zelenikhin, PV and Stoikov, II}, title = {Toward Pathogenic Biofilm Suppressors: Synthesis of Amino Derivatives of Pillar[5]arene and Supramolecular Assembly with DNA.}, journal = {Pharmaceutics}, volume = {15}, number = {2}, pages = {}, pmid = {36839796}, issn = {1999-4923}, support = {22-73-10166//Russian Science Foundation/ ; }, abstract = {New amino derivatives of pillar[5]arene were obtained in three stages with good yields. It was shown that pillar[5]arene containing thiaether and tertiary amino groups formed supramolecular complexes with low molecular weight model DNA. Pillar[5]arene formed complexes with a DNA nucleotide pair at a ratio of 1:2 (macrocycle/DNA base pairs), as demonstrated by UV-visible and fluorescence spectroscopy. The association constants of pillar[5]arene with DNA were lgKass1:1 = 2.38 and lgKass1:2 = 5.07, accordingly. By using dynamic light scattering and transmission electron microscopy, it was established that the interaction of pillar[5]arene containing thiaether and tertiary amino groups (concentration of 10-5 M) with a model nucleic acid led to the formation of stable nanosized macrocycle/DNA associates with an average particle size of 220 nm. It was shown that the obtained compounds did not exhibit a pronounced toxicity toward human adenocarcinoma cells (A549) and bovine lung epithelial cells (LECs). The hypothesis about a possible usage of the synthesized macrocycle for the aggregation of extracellular bacterial DNA in a biofilm matrix was confirmed by the example of St. Aureus. It was found that pillar[5]arene at a concentration of 10[-5] M was able to reduce the thickness of the St. Aureus biofilm by 15%.}, } @article {pmid36839785, year = {2023}, author = {MubarakAli, D and Arunachalam, K and Lakshmanan, M and Badar, B and Kim, JW and Lee, SY}, title = {Unveiling the Anti-Biofilm Property of Hydroxyapatite on Pseudomonas aeruginosa: Synthesis and Strategy.}, journal = {Pharmaceutics}, volume = {15}, number = {2}, pages = {}, pmid = {36839785}, issn = {1999-4923}, abstract = {Biofilm-related nosocomial infections may cause a wide range of life-threatening infections. In this regard, Pseudomonas aeruginosa biofilm is becoming a serious health burden due to its capability to develop resistance to natural and synthetic drugs. The utilization of nanoparticles that inhibit biofilm formation is one of the major strategies to control infections caused by biofilm-forming pathogens. Hydroxyapatite (HA) is a synthetic ceramic material having properties similar to natural bones. Herein, a co-precipitation method followed by microwave treatment was used to synthesize HA nanoparticles (HANPs). The resulting HANPs were characterized using X-ray diffraction and transmission electron microscopy. Then, their antibiofilm properties against P. aeruginosa ATCC 10145 were examined in vitro. The needle-shaped HANPs were 30 and 90 nm long in width and length, respectively. The synthesized HANPs inhibited the biofilm formation of P. aeruginosa ATCC 10145 in a concentration-dependent manner, which was validated by light and confocal laser scanning microscopy. Hence, this study demonstrated that HANPs could be used to control the biofilm-related infections of P. aeruginosa.}, } @article {pmid36839583, year = {2023}, author = {Bonsaglia, ECR and Rossi, RS and Latosinski, G and Rossi, BF and Campos, FC and Junior, AF and Pantoja, JCF and Rall, VLM}, title = {Relationship between Biofilm Production and High Somatic Cell Count in Streptococcus agalactiae Isolated from Milk of Cows with Subclinical Mastitis.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36839583}, issn = {2076-0817}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Streptococcus agalactiae (S. agalactiae) is one of the main agents that causes mastitis in dairy cows, mainly inducing the subclinical form, which is characterized by a high somatic cell count (SCC). The aim of this study was to correlate the increase in SCC caused by S. agalactiae in cows with subclinical mastitis to the presence of genes related to adhesion and invasion in bovine mammary epithelial cells (BMEC) and biofilm formation. Considering the 145 isolates tested, 57.2% presented the capsular type Ia and 42.8% presented type III. We identified the virulence genes among the isolates and determined nine genetic profiles. The most common profile was identified in 69 isolates (47.5%): Ia, fbsA[+], fbsB[-], pI1[-], pI2a[-], pI2b[+], and hylb[+]. All isolates produced biofilm, with 58.6% classified as strong producers, 29% as moderate producers and 12.4% as weak producers. No statistical correlation was found between the presence of virulence genes and increased SCC or biofilm production. However, biological evidence was observed between increased SCC and biofilm production. One isolate from each profile was randomly subjected to adhesion and invasion assays, and all of them adhered to BEMC, but none were able to invade. Our results showed that different genetic profiles do not provide advantages for bacteria to invade BMEC in vitro. In addition, biofilm production appears to be related to high SCC.}, } @article {pmid36839449, year = {2023}, author = {Kudinova, A and Grishin, A and Grunina, T and Poponova, M and Bulygina, I and Gromova, M and Choudhary, R and Senatov, F and Karyagina, A}, title = {Antibacterial and Anti-Biofilm Properties of Diopside Powder Loaded with Lysostaphin.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36839449}, issn = {2076-0817}, support = {22-15-00216//Russian Science Foundation/ ; }, abstract = {BACKGROUND: Diopside-based ceramic is a perspective biocompatible material with numerous potential applications in the field of bone prosthetics. Implantable devices and materials are often prone to colonization and biofilm formation by pathogens such as Staphylococcus aureus, which in the case of bone grafting leads to osteomyelitis, an infectious bone and bone marrow injury. To lower the risk of bacterial colonization, implanted materials can be impregnated with antimicrobials. In this work, we loaded the antibacterial enzyme lysostaphin on diopside powder and studied the antibacterial and antibiofilm properties of such material to probe the utility of this approach for diopside-based prosthetic materials.

METHODS: Diopside powder was synthesized by the solid-state method, lysostaphin was loaded on diopside by adsorption, the release of lysostaphin from diopside was monitored by ELISA, and antibacterial and anti-biofilm activity was assessed by standard microbiological procedures.

RESULTS AND CONCLUSIONS: Lysostaphin released from diopside powder showed high antibacterial activity against planktonic bacteria and effectively destroyed 24-h staphylococcal biofilms. Diopside-based materials possess a potential for the development of antibacterial bone grafting materials.}, } @article {pmid36838900, year = {2023}, author = {Essghaier, B and Mallat, N and Khwaldia, K and Mottola, F and Rocco, L and Hannachi, H}, title = {Production and Characterization of New Biosurfactants/Bioemulsifiers from Pantoea alhagi and Their Antioxidant, Antimicrobial and Anti-Biofilm Potentiality Evaluations.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {4}, pages = {}, pmid = {36838900}, issn = {1420-3049}, mesh = {Humans ; *Antioxidants/pharmacology ; Biofilms ; *Anti-Infective Agents/pharmacology ; Fatty Acids/pharmacology ; }, abstract = {The present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. Results indicated that the new BS evidenced an E24 emulsification index of 82%. Fourier-transform infrared (FTIR) results mentioned that the described BS belong to the glycolipid family. Fatty acid profiles showed the predominance of methyl 2-hyroxydodecanoate in the cell membrane (67.00%) and methyl 14-methylhexadecanoate (12.05%). The major fatty acid in the BS was oleic acid (76.26%), followed by methyl 12-methyltetradecanoate (10.93%). Markedly, the BS produced by the Pantoea alhagi species exhibited antimicrobial and anti-biofilm activities against tested human pathogens. With superior antibacterial activity against Escherchia coli and Staphylococcus aureus, a high antifungal effect was given against Fusarium sp. with a diameter of zone of inhibition of 29.5 mm, 36 mm and 31 mm, obtained by BS dissolved in methanol extract. The DPPH assay indicated that the BS (2 mg/mL) showed a higher antioxidant activity (78.07 inhibition percentage). The new BS exhibited specific characteristics, encouraging their use in various industrial applications.}, } @article {pmid36838823, year = {2023}, author = {Nile, SH and Thombre, D and Shelar, A and Gosavi, K and Sangshetti, J and Zhang, W and Sieniawska, E and Patil, R and Kai, G}, title = {Antifungal Properties of Biogenic Selenium Nanoparticles Functionalized with Nystatin for the Inhibition of Candida albicans Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {28}, number = {4}, pages = {}, pmid = {36838823}, issn = {1420-3049}, mesh = {Humans ; Antifungal Agents/pharmacology ; Nystatin/pharmacology ; *Selenium/chemistry ; Candida albicans ; Nanoconjugates ; *Nanoparticles/chemistry ; Biofilms ; }, abstract = {In the present study, biogenic selenium nanoparticles (SeNPs) have been prepared using Paenibacillus terreus and functionalized with nystatin (SeNP@PVP_Nystatin nanoconjugates) for inhibiting growth, morphogenesis, and a biofilm in Candida albicans. Ultraviolet-visible spectroscopy analysis has shown a characteristic absorption at 289, 303, and 318 nm, and X-ray diffraction analysis has shown characteristic peaks at different 2θ values for SeNPs. Electron microscopy analysis has shown that biogenic SeNPs are spherical in shape with a size in the range of 220-240 nm. Fourier transform infrared spectroscopy has confirmed the functionalization of nystatin on SeNPs (formation of SeNP@PVP_Nystatin nanoconjugates), and the zeta potential has confirmed the negative charge on the nanoconjugates. Biogenic SeNPs are inactive; however, nanoconjugates have shown antifungal activities on C. albicans (inhibited growth, morphogenesis, and a biofilm). The molecular mechanism for the action of nanoconjugates via a real-time polymerase chain reaction has shown that genes involved in the RAS/cAMP/PKA signaling pathway play an important role in antifungal activity. In cytotoxic studies, nanoconjugates have inhibited only 12% growth of the human embryonic kidney cell line 293 cells, indicating that the nanocomposites are not cytotoxic. Thus, the biogenic SeNPs produced by P. terreus can be used as innovative and effective drug carriers to increase the antifungal activity of nystatin.}, } @article {pmid36838422, year = {2023}, author = {Morris, D and Flores, M and Harris, L and Gammon, J and Nigam, Y}, title = {Larval Therapy and Larval Excretions/Secretions: A Potential Treatment for Biofilm in Chronic Wounds? A Systematic Review.}, journal = {Microorganisms}, volume = {11}, number = {2}, pages = {}, pmid = {36838422}, issn = {2076-2607}, abstract = {Chronic wounds present a global healthcare challenge and are increasing in prevalence, with bacterial biofilms being the primary roadblock to healing in most cases. A systematic review of the to-date knowledge on larval therapy's interaction with chronic-wound biofilm is presented here. The findings detail how larval therapy-the controlled application of necrophagous blowfly larvae-acts on biofilms produced by chronic-wound-relevant bacteria through their principle pharmacological mode of action: the secretion and excretion of biologically active substances into the wound bed. A total of 12 inclusion-criteria-meeting publications were identified following the application of a PRISMA-guided methodology for a systematic review. The findings of these publications were qualitatively analyzed to provide a summary of the prevailing understanding of larval therapy's effects on bacterial biofilm. A further review assessed the quality of the existing evidence to identify knowledge gaps and suggest ways these may be bridged. In summary, larval therapy has a seemingly unarguable ability to inhibit and degrade bacterial biofilms associated with impaired wound healing. However, further research is needed to clarify and standardize the methodological approach in this area of investigation. Such research may lead to the clinical application of larval therapy or derivative treatments for the management of chronic-wound biofilms and improve patient healing outcomes at a time when alternative therapies are desperately needed.}, } @article {pmid36838406, year = {2023}, author = {Di Bonaventura, G and Picciani, C and Lupetti, V and Pompilio, A}, title = {Comparative Proteomic Analysis of Protein Patterns of Stenotrophomonas maltophilia in Biofilm and Planktonic Lifestyles.}, journal = {Microorganisms}, volume = {11}, number = {2}, pages = {}, pmid = {36838406}, issn = {2076-2607}, support = {FAR-2020//University of Chieti-Pescara/ ; FFC 7/2007//Cystic Fibrosis Research Foundation/ ; }, abstract = {Stenotrophomonas maltophilia is a clinically relevant bacterial pathogen, particularly in cystic fibrosis (CF) patients. Despite the well-known ability to form biofilms inherently resistant to antibiotics and host immunity, many aspects involved in S. maltophilia biofilm formation are yet to be elucidated. In the present study, a proteomic approach was used to elucidate the differential protein expression patterns observed during the planktonic-to-biofilm transition of S. maltophilia Sm126, a strong biofilm producer causing chronic infection in a CF patient, to identify determinants potentially associated with S. maltophilia biofilm formation. In all, 57 proteins were differentially (3-fold; p < 0.01) expressed in biofilm cells compared with planktonic counterparts: 38 were overexpressed, and 19 were down-expressed. It is worth noting that 34 proteins were exclusively found in biofilm, mainly associated with quorum sensing-mediated intercellular communication, augmented glycolysis, amino acid metabolism, biosynthesis of secondary metabolites, phosphate signaling, response to nutrient starvation, and general stress. Further work is warranted to evaluate if these proteins can be suitable targets for developing anti-biofilm strategies effective against S. maltophilia.}, } @article {pmid36838220, year = {2023}, author = {Viksne, R and Racenis, K and Broks, R and Balode, AO and Kise, L and Kroica, J}, title = {In Vitro Assessment of Biofilm Production, Antibacterial Resistance of Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter spp. Obtained from Tonsillar Crypts of Healthy Adults.}, journal = {Microorganisms}, volume = {11}, number = {2}, pages = {}, pmid = {36838220}, issn = {2076-2607}, abstract = {BACKGROUND AND OBJECTIVE: Tonsillar crypts can be considered a reservoir for a variety of bacterial species. Some bacterial species can be considered part of the normal oropharyngeal microbiota. The roles of other pathogens, for example, the so-called non-oral and respiratory pathogens Staphylococcus aureus, Klebsiella, Pseudomonas, and Acinetobacter spp., which have strong virulence factors, biofilm production capacity, and the ability to initiate infectious diseases, are unclear. The purpose of this study was to detect the presence of S. aureus, K. pneumoniae, P. aeruginosa, and Acinetobacter spp. within the tonsillar crypts of healthy individuals, and to analyze the pathogens' biofilm production and antibacterial resistances.

RESULTS: Only common oropharyngeal microbiota were cultivated from 37 participant samples (40.7%). The most commonly isolated pathogenic bacterium was S. aureus, which was isolated in 41 (45%) participant samples. K. pneumoniae was isolated in seven (7.7%) samples, Acinetobacter spp. were isolated in five (5.5%) samples, and P. aeruginosa was isolated in two (2.2%) samples. Biofilm producers predominated among the pathogenic bacteria; 51 strains were biofilm producers, and among them, 31 strains were moderate or strong biofilm producers. The tested S. aureus, K. pneumoniae, P. aeruginosa, and Acinetobacter spp. strains were sensitive to commonly used antibiotics (amoxicillin-clavulanic acid, clindamycin, or ciprofloxacin). One of the isolated S. aureus strains was MRSA.

CONCLUSIONS: Biofilm is a commonly observed feature that seems to be a naturally existing form of pathogenic bacteria colonizing human tissue. S. aureus, K. pneumoniae, P. aeruginosa, and Acinetobacter spp. occasionally occur in the tonsillar crypts of healthy individuals, and, therefore, it is most likely that S. aureus, K. pneumoniae, P. aeruginosa, and Acinetobacter spp. in opportunistic tonsillar infections originate from the tonsillar crypt microbiota.}, } @article {pmid36837628, year = {2023}, author = {Yang, H and Xu, Z and Xu, Z and Li, Y}, title = {Mini-Review of Biofilm Interactions with Surface Materials in Industrial Piping System.}, journal = {Membranes}, volume = {13}, number = {2}, pages = {}, pmid = {36837628}, issn = {2077-0375}, abstract = {The growth of biofilm, which is caused by microorganism accumulation and growth on wetted surfaces, may damage industrial piping systems, increase maintenance and cleaning costs for the system sterilization, and even divulge the immune system into high risk. This article systematically analyzes the biofilm interactions with piping surface materials from the perspectives of physical convection, and biological and chemical adhesion. The thermodynamics of the flow, bacterial surface sensing, and bio-communication are the most critical factors for biofilm attachment. Furthermore, experimental analysis methods as well as biofilm control and removal approaches, are also included in this study. Finally, the resistance and growth of biofilm, as well as the practical and advanced methodology to control the biofilm and challenges associated with technology, are also discussed. Moreover, this paper may also offer a significant reference for the practice and strategic applications to address the biofilm resistance issues in industrial piping.}, } @article {pmid36836905, year = {2023}, author = {Abdulhakeem, MA and Alreshidi, M and Bardakci, F and Hamadou, WS and De Feo, V and Noumi, E and Snoussi, M}, title = {Molecular Identification of Bacteria Isolated from Marketed Sparus aurata and Penaeus indicus Sea Products: Antibiotic Resistance Profiling and Evaluation of Biofilm Formation.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, pmid = {36836905}, issn = {2075-1729}, abstract = {BACKGROUND: Marketed fish and shellfish are a source of multidrug-resistant and biofilm-forming foodborne pathogenic microorganisms.

METHODS: Bacteria isolated from Sparus aurata and Penaeus indicus collected from a local market in Hail region (Saudi Arabia) were isolated on selective and chromogenic media and identified by using 16S RNA sequencing technique. The exoenzyme production and the antibiotic susceptibility patterns of all identified bacteria were also tested. All identified bacteria were tested for their ability to form biofilm by using both qualitative and quantitative assays.

RESULTS: Using 16S RNA sequencing method, eight genera were identified dominated by Vibrio (42.85%), Aeromonas (23.80%), and Photobacterium (9.52%). The dominant species were V. natrigens (23.8%) and A. veronii (23.80%). All the identified strains were able to produce several exoenzymes (amylases, gelatinase, haemolysins, lecithinase, DNase, lipase, and caseinase). All tested bacteria were multidrug-resistant with a high value of the multiple antibiotic index (MARI). The antibiotic resistance index (ARI) was about 0.542 for Vibrio spp. and 0.553 for Aeromonas spp. On Congo red agar, six morphotypes were obtained, and 33.33% were slime-positive bacteria. Almost all tested microorganisms were able to form a biofilm on glass tube. Using the crystal violet technique, the tested bacteria were able to form a biofilm on glass, plastic, and polystyrene abiotic surfaces with different magnitude.

CONCLUSIONS: Our findings suggest that marketed S. aurata and P. indicus harbor various bacteria with human interest that are able to produce several related-virulence factors.}, } @article {pmid36836852, year = {2023}, author = {Gajewska, J and Chajęcka-Wierzchowska, W and Byczkowska-Rostkowska, Z and Saki, M}, title = {Biofilm Formation Capacity and Presence of Virulence Determinants among Enterococcus Species from Milk and Raw Milk Cheeses.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, pmid = {36836852}, issn = {2075-1729}, abstract = {Bacterial biofilm is one of the major hazards facing the food industry. Biofilm-forming ability is one of the most important virulence properties of enterococci. The genus Enterococcus includes pathogenic, spoilage, and pro-technological bacteria. The presence of enterococci in milk and dairy products is usually associated with inadequate hygiene practices. The study examined the isolates' capacity for biofilm formation and identification of the genetic determinants of its formation among 85 Enterococcus strains isolated from raw milk (n = 49) and soft-ripened cheeses made from unpasteurized milk (n = 36). E. faecalis and E. faecium were the dominant species. The obtained results showed that 41.4% isolates from milk and 50.0% isolates from cheeses were able to form biofilm. All of the isolates analyzed had at least one of the studied genes. As regards the isolates from raw milk, the most prevalent gene was the gelE (85.6%), followed by the asa1 (66.7%). None of the isolates from cheeses showed the presence of cylA and sprE. The most prevalent gene among the strains from this source was the epbC (94.4%), followed by the gelE (88.9%). In isolates from both sources, the presence of proteins from the Fsr group was noted the least frequently. Nevertheless, results showed that were no significant differences between the biofilm-producing Enterococcus spp. and non-biofilm-producing isolates in term of occurrences of tested virulence genes. The ability to produce a biofilm by enterococci isolated from raw milk or ready-to-eat products emphasizes the need for continuous monitoring of the mechanisms of microbial adhesion.}, } @article {pmid36836656, year = {2023}, author = {Dhaouadi, S and Romdhani, A and Bouglita, W and Chedli, S and Chaari, S and Soufi, L and Cherif, A and Mnif, W and Abbassi, MS and Elandoulsi, RB}, title = {High Biofilm-Forming Ability and Clonal Dissemination among Colistin-Resistant Escherichia coli Isolates Recovered from Cows with Mastitis, Diarrheic Calves, and Chickens with Colibacillosis in Tunisia.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, pmid = {36836656}, issn = {2075-1729}, abstract = {BACKGROUND: Escherichia coli (E. coli) is one of the main etiological agents responsible for bovine mastitis (BM), neonatal calf diarrhea (NCD), and avian colibacillosis (AC). This study aimed to assess resistance and virulence genes content, biofilm-forming ability, phylogenetic groups, and genetic relatedness in E. coli isolates recovered from clinical cases of BM, NCD, and AC.

MATERIALS/METHODS: A total of 120 samples including samples of milk (n = 70) and feces (n = 50) from cows with BM and calves with NCD, respectively, were collected from different farms in Northern Tunisia. Bacterial isolation and identification were performed. Then, E. coli isolates were examined by disk diffusion and broth microdilution method for their antimicrobial susceptibility and biofilm-forming ability. PCR was used to detect antimicrobial resistance genes (ARGs), virulence genes (VGs), phylogenetic groups, and Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for their clonal relationship.

RESULTS: Among the 120 samples, 67 E. coli isolates (25 from BM, 22 from AC, and 20 from NCD) were collected. Overall, 83.6% of isolates were multidrug resistant. Thirty-six (53.73%) isolates were phenotypically colistin-resistant (CREC), 28.3% (19/67) were ESBL producers (ESBL-EC), and forty-nine (73.1%) formed biofilm. The blaTEM gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the blaCTXM-g-1 gene was detected in 47.3% (9/19) of isolates, all from AC. The most common VG was the fimA gene (26/36, 72.2%), followed by aer (12/36, 33.3%), cnf1 (6/36, 16.6%), papC (4/36, 11.1%), and stx1 and stx2 genes (2/36; 5.5% for each). Phylogenetic analysis showed that isolates belonged to three groups: A (20/36; 55.5%), B2 (7/36; 19.4%), and D (6/36; 16.6%). Molecular typing by ERIC-PCR showed high genetic diversity of CREC and ESBL E. coli isolates from the three animal diseases and gave evidence of their clonal dissemination within farms in Tunisia.

CONCLUSION: The present study sheds new light on the biofilm-forming ability and clonality within CREC and ESBL-EC isolated from three different animal diseases in Tunisian farm animals.}, } @article {pmid36835662, year = {2023}, author = {Sánchez-Lozano, I and Muñoz-Cruz, LC and Hellio, C and Band-Schmidt, CJ and Cruz-Narváez, Y and Becerra-Martínez, E and Hernández-Guerrero, CJ}, title = {Metabolomic Insights of Biosurfactant Activity from Bacillus niabensis against Planktonic Cells and Biofilm of Pseudomonas stutzeri Involved in Marine Biofouling.}, journal = {International journal of molecular sciences}, volume = {24}, number = {4}, pages = {}, pmid = {36835662}, issn = {1422-0067}, support = {SIP-20221829, SIP-20221626, SIP-20221652//Instituto Politécnico Nacional/ ; A1-S-14968//CONACYT/ ; }, mesh = {*Biofouling ; *Pseudomonas stutzeri ; Plankton ; NADP/metabolism ; Trehalose/metabolism ; Biofilms ; *Bacillus ; }, abstract = {In marine environments, biofilm can cause negative impacts, including the biofouling process. In the search for new non-toxic formulations that inhibit biofilm, biosurfactants (BS) produced by the genus Bacillus have demonstrated considerable potential. To elucidate the changes that BS from B. niabensis promote in growth inhibition and biofilm formation, this research performed a nuclear magnetic resonance (NMR) metabolomic profile analysis to compare the metabolic differences between planktonic cells and biofilms of Pseudomonas stutzeri, a pioneer fouling bacteria. The multivariate analysis showed a clear separation between groups with a higher concentration of metabolites in the biofilm than in planktonic cells of P. stutzeri. When planktonic and biofilm stages were treated with BS, some differences were found among them. In planktonic cells, the addition of BS had a minor effect on growth inhibition, but at a metabolic level, NADP+, trehalose, acetone, glucose, and betaine were up-regulated in response to osmotic stress. When the biofilm was treated with the BS, a clear inhibition was observed and metabolites such as glucose, acetic acid, histidine, lactic acid, phenylalanine, uracil, and NADP+ were also up-regulated, while trehalose and histamine were down-regulated in response to the antibacterial effect of the BS.}, } @article {pmid36835442, year = {2023}, author = {Balducci, E and Papi, F and Capialbi, DE and Del Bino, L}, title = {Polysaccharides' Structures and Functions in Biofilm Architecture of Antimicrobial-Resistant (AMR) Pathogens.}, journal = {International journal of molecular sciences}, volume = {24}, number = {4}, pages = {}, pmid = {36835442}, issn = {1422-0067}, mesh = {*Antifungal Agents/pharmacology ; Polysaccharides/metabolism ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Bacteria ; Polysaccharides, Bacterial/metabolism ; }, abstract = {Bacteria and fungi have developed resistance to the existing therapies such as antibiotics and antifungal drugs, and multiple mechanisms are mediating this resistance. Among these, the formation of an extracellular matrix embedding different bacterial cells, called biofilm, is an effective strategy through which bacterial and fungal cells are establishing a relationship in a unique environment. The biofilm provides them the possibility to transfer genes conferring resistance, to prevent them from desiccation and to impede the penetration of antibiotics or antifungal drugs. Biofilms are formed of several constituents including extracellular DNA, proteins and polysaccharides. Depending on the bacteria, different polysaccharides form the biofilm matrix in different microorganisms, some of them involved in the first stage of cells' attachment to surfaces and to each other, and some responsible for giving the biofilm structure resistance and stability. In this review, we describe the structure and the role of different polysaccharides in bacterial and fungal biofilms, we revise the analytical methods to characterize them quantitatively and qualitatively and finally we provide an overview of potential new antimicrobial therapies able to inhibit biofilm formation by targeting exopolysaccharides.}, } @article {pmid36834746, year = {2023}, author = {Ji, MK and Lee, SK and Kim, HS and Oh, GJ and Cho, H and Lim, HP}, title = {Assessment of Inhibition of Biofilm Formation on Non-Thermal Plasma-Treated TiO2 Nanotubes.}, journal = {International journal of molecular sciences}, volume = {24}, number = {4}, pages = {}, pmid = {36834746}, issn = {1422-0067}, support = {NRF-2020R1C1C1005683//National Research Foundation of Korea/ ; }, mesh = {Humans ; *Peri-Implantitis ; *Dental Implants ; *Nanotubes/chemistry ; Biofilms ; Titanium/chemistry ; Surface Properties ; Streptococcus mutans ; }, abstract = {Peri-implantitis is an inflammatory disease similar to periodontitis, caused by biofilms formed on the surface of dental implants. This inflammation can spread to bone tissues and result in bone loss. Therefore, it is essential to inhibit the formation of biofilms on the surface of dental implants. Thus, this study examined the inhibition of biofilm formation by treating TiO2 nanotubes with heat and plasma. Commercially pure titanium specimens were anodized to form TiO2 nanotubes. Heat treatment was performed at 400 and 600 °C, and atmospheric pressure plasma was applied using a plasma generator (PGS-200, Expantech, Suwon, Republic of Korea). Contact angles, surface roughness, surface structure, crystal structure, and chemical compositions were measured to analyze the surface properties of the specimens. The inhibition of biofilm formation was assessed using two methods. The results of this study showed that the heat treatment of TiO2 nanotubes at 400 °C inhibited the adhesion of Streptococcus mutans (S. mutans), associated with initial biofilm formation, and that heat treatment of TiO2 nanotubes at 600 °C inhibited the adhesion of Porphyromonas gingivalis (P. gingivalis), which causes peri-implantitis. Applying plasma to the TiO2 nanotubes heat-treated at 600 °C inhibited the adhesion of S. mutans and P. gingivalis.}, } @article {pmid36834725, year = {2023}, author = {Karczewska, M and Strzelecki, P and Bogucka, K and Potrykus, K and Szalewska-Pałasz, A and Nowicki, D}, title = {Increased Levels of (p)ppGpp Correlate with Virulence and Biofilm Formation, but Not with Growth, in Strains of Uropathogenic Escherichia coli.}, journal = {International journal of molecular sciences}, volume = {24}, number = {4}, pages = {}, pmid = {36834725}, issn = {1422-0067}, support = {UMO-2016/21/B/NZ7/02077//National Science Center/ ; 2018/31/D/NZ7/02258//National Science Center/ ; 1220/29/2022//University of Gdańsk/ ; }, mesh = {Humans ; Virulence/genetics ; Anti-Bacterial Agents/pharmacology ; *Uropathogenic Escherichia coli/genetics ; Guanosine Pentaphosphate ; *Escherichia coli Infections/microbiology ; Virulence Factors/genetics ; *Urinary Tract Infections/microbiology ; }, abstract = {Urinary tract infections are one of the most frequent bacterial diseases worldwide. UPECs are the most prominent group of bacterial strains among pathogens responsible for prompting such infections. As a group, these extra-intestinal infection-causing bacteria have developed specific features that allow them to sustain and develop in their inhabited niche of the urinary tract. In this study, we examined 118 UPEC isolates to determine their genetic background and antibiotic resistance. Moreover, we investigated correlations of these characteristics with the ability to form biofilm and to induce a general stress response. We showed that this strain collection expressed unique UPEC attributes, with the highest representation of FimH, SitA, Aer, and Sfa factors (100%, 92.5%, 75%, and 70%, respectively). According to CRA (Congo red agar) analysis, the strains particularly predisposed to biofilm formation represented 32.5% of the isolates. Those biofilm forming strains presented a significant ability to accumulate multi-resistance traits. Most notably, these strains presented a puzzling metabolic phenotype-they showed elevated basal levels of (p)ppGpp in the planktonic phase and simultaneously exhibited a shorter generation time when compared to non-biofilm-forming strains. Moreover, our virulence analysis showed these phenotypes to be crucial for the development of severe infections in the Galleria mellonella model.}, } @article {pmid36834695, year = {2023}, author = {Ismail, S and Gaglione, R and Masi, M and Padhi, S and Rai, AK and Omar, G and Cimmino, A and Arciello, A}, title = {Ephedra foeminea as a Novel Source of Antimicrobial and Anti-Biofilm Compounds to Fight Multidrug Resistance Phenotype.}, journal = {International journal of molecular sciences}, volume = {24}, number = {4}, pages = {}, pmid = {36834695}, issn = {1422-0067}, mesh = {*Kaempferols/pharmacology ; Staphylococcus aureus ; Molecular Docking Simulation ; *Anti-Infective Agents/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Plant Extracts/pharmacology ; Drug Resistance, Multiple ; Microbial Sensitivity Tests ; }, abstract = {Plants are considered a wealthy resource of novel natural drugs effective in the treatment of multidrug-resistant infections. Here, a bioguided purification of Ephedra foeminea extracts was performed to identify bioactive compounds. The determination of antimicrobial properties was achieved by broth microdilution assays to evaluate minimal inhibitory concentration (MIC) values and by crystal violet staining and confocal laser scanning microscopy analyses (CLSM) to investigate the antibiofilm capacity of the isolated compounds. Assays were performed on a panel of three gram-positive and three gram-negative bacterial strains. Six compounds were isolated from E. foeminea extracts for the first time. They were identified by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) analyses as the well-known monoterpenoid phenols carvacrol and thymol and as four acylated kaempferol glycosides. Among them, the compound kaempferol-3-O-α-L-(2″,4″-di-E-p-coumaroyl)-rhamnopyranoside was found to be endowed with strong antibacterial properties and significant antibiofilm activity against S. aureus bacterial strains. Moreover, molecular docking studies on this compound suggested that the antibacterial activity of the tested ligand against S. aureus strains might be correlated to the inhibition of Sortase A and/or of tyrosyl tRNA synthase. Collectively, the results achieved open interesting perspectives to kaempferol-3-O-α-L-(2″,4″-di-E-p-coumaroyl)-rhamnopyranoside applicability in different fields, such as biomedical applications and biotechnological purposes such as food preservation and active packaging.}, } @article {pmid36831057, year = {2023}, author = {Avraham, M and Steinberg, D and Barak, T and Shalish, M and Feldman, M and Sionov, RV}, title = {Improved Anti-Biofilm Effect against the Oral Cariogenic Streptococcus mutans by Combined Triclosan/CBD Treatment.}, journal = {Biomedicines}, volume = {11}, number = {2}, pages = {}, pmid = {36831057}, issn = {2227-9059}, abstract = {Streptococcus mutans is a Gram-positive bacterium highly associated with dental caries, and it has a strong biofilm-forming ability, especially in a sugar-rich environment. Many strategies have been undertaken to prevent dental caries by targeting these bacteria. Recently, we observed that a sustained-release varnish containing triclosan and cannabidiol (CBD) was more efficient than each compound alone in preventing biofilm formation by the fungus Candida albicans, which is frequently involved in oral infections together with S. mutans. It was therefore inquiring to study the effect of this drug combination on S. mutans. We observed that the combined treatment of triclosan and CBD had stronger anti-bacterial and anti-biofilm activity than each compound alone, thus enabling the use of lower concentrations of each drug to achieve the desired effect. The combined drug treatment led to an increase in the SYTO 9[low], propidium iodide (PI)[high] bacterial population as analyzed by flow cytometry, indicative for bacteria with disrupted membrane. Both triclosan and CBD induced membrane hyperpolarization, although there was no additive effect on this parameter. HR-SEM images of CBD-treated bacteria show the appearance of elongated and swollen bacteria with several irregular septa structures, and upon combined treatment with triclosan, the bacteria took on a swollen ellipse and sometimes oval morphology. Increased biofilm formation was observed at sub-MIC concentrations of each compound alone, while combining the drugs at these sub-MIC concentrations, the biofilm formation was prevented. The inhibition of biofilm formation was confirmed by CV biomass staining, MTT metabolic activity, HR-SEM and live/dead together with exopolysaccharide (EPS) staining visualized by spinning disk confocal microscopy. Importantly, the concentrations required for the anti-bacterial and anti-biofilm activities toward S. mutans were non-toxic to the normal Vero epithelial cells. In conclusion, the data obtained in this study propose a beneficial role of combined triclosan/CBD treatment for potential protection against dental caries.}, } @article {pmid36830328, year = {2023}, author = {Abd El-Rahman, OA and Rasslan, F and Hassan, SS and Ashour, HM and Wasfi, R}, title = {The RND Efflux Pump Gene Expression in the Biofilm Formation of Acinetobacter baumannii.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830328}, issn = {2079-6382}, abstract = {Multidrug resistant (MDR) Acinetobacter baumannii is a critical opportunistic pathogen in healthcare-associated infections (HAI). This is attributed to several factors, including its ability to develop biofilms that can enhance antimicrobial resistance (AMR) in addition to creating an environment for horizontal transfer of antibiotic resistance genes. The role of the efflux pump in biofilm formation is important for studies on alternative treatments for biofilms. One of the significant efflux pump families is the RND efflux pump family, which is common in Gram negative bacteria. The aim is to study the role of the RND efflux pump in biofilm formation by A. baumannii. The biofilm formation potential of thirty-four MDR A. baumannii isolates was evaluated by crystal violet assays. The effect of efflux pump inhibition and activation was studied using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and the RND efflux pump substrate levofloxacin (at sub-MIC), respectively. The isolates were genotypically grouped by enterobacterial repetitive intergenic consensus (ERIC) typing and the expression of adeABC, adeFGH, and adeIJK efflux pump genes was measured by qPCR. Overall, 88.2% (30/34) of isolates were biofilm producers (the phenotype was variable including strong and weak producers). Efflux pump inhibition by CCCP reduced the biofilm formation significantly (p < 0.05) in 17.6% (6/34) of some isolates, whereas sub-MICs of the substrate levofloxacin increased biofilm formation in 20.5% (7/34) of other isolates. Overexpression of the three RND efflux pump genes was detected in five out of eleven selected isolates for qPCR with remarkable overexpression in the adeJ gene. No correlation was detected between the biofilm phenotype pattern and the RND efflux pump gene expression in biofilm cells relative to planktonic cells. In conclusion, the role of the RND efflux pumps AdeABC, AdeFGH, and AdeIJK in biofilm formation does not appear to be pivotal and the expression differs according to the genetic background of each strain. Thus, these pumps may not be a promising target for biofilm inhibition.}, } @article {pmid36830299, year = {2023}, author = {Ridyard, KE and Elsawy, M and Mattrasingh, D and Klein, D and Strehmel, J and Beaulieu, C and Wong, A and Overhage, J}, title = {Synergy between Human Peptide LL-37 and Polymyxin B against Planktonic and Biofilm Cells of Escherichia coli and Pseudomonas aeruginosa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830299}, issn = {2079-6382}, support = {Startup Funds//Carleton University/ ; Funding//Natural Sciences and Engineering Research Council of Canada (NSERC)/ ; }, abstract = {The rise in antimicrobial resistant bacteria is limiting the number of effective treatments for bacterial infections. Escherichia coli and Pseudomonas aeruginosa are two of the pathogens with the highest prevalence of resistance, and with the greatest need for new antimicrobial agents. Combinations of antimicrobial peptides (AMPs) and antibiotics that display synergistic effects have been shown to be an effective strategy in the development of novel therapeutic agents. In this study, we investigated the synergy between the AMP LL-37 and various classes of antibiotics against E. coli and P. aeruginosa strains. Of the six antibiotics tested (ampicillin, tetracycline, ciprofloxacin, gentamicin, aztreonam, and polymyxin B (PMB)), LL-37 displayed the strongest synergy against E. coli MG1655 and P. aeruginosa PAO1 laboratory strains when combined with PMB. Given the strong synergy, the PMB + LL-37 combination was chosen for further examination where it demonstrated synergy against multidrug-resistant and clinical E. coli isolates. Synergy of PMB + LL-37 towards clinical isolates of P. aeruginosa varied and showed synergistic, additive, or indifferent effects. The PMB + LL-37 combination treatment showed significant prevention of biofilm formation as well as eradication of pre-grown E. coli and P. aeruginosa biofilms. Using the Galleria mellonella wax worm model, we showed that the PMB + LL-37 combination treatment retained its antibacterial capacities in vivo. Flow analyses were performed to characterize the mode of action. The results of the present study provide proof of principle for the synergistic response between LL-37 and PMB and give novel insights into a promising new antimicrobial combination against gram-negative planktonic and biofilm cells.}, } @article {pmid36830295, year = {2023}, author = {Ersanli, C and Tzora, A and Skoufos, I and Fotou, K and Maloupa, E and Grigoriadou, K and Voidarou, CC and Zeugolis, DI}, title = {The Assessment of Antimicrobial and Anti-Biofilm Activity of Essential Oils against Staphylococcus aureus Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830295}, issn = {2079-6382}, support = {Τ9ΕΡΑ3-00022//European Union, EuroNanoMed3, project nAngioDerm, through the Greek General Secretariat for Research and Innovation ERA-NETS/ ; }, abstract = {The increase in antimicrobial resistance and tolerance over the years has become a serious public health problem, leading to the inevitable development of alternative antimicrobial agents as substitutes for industrial pharmaceutical antibiotics targeting humans and animals under the concept of one health. Essential oils (EOs) extracted from aromatic and pharmaceutical plants incorporate several bioactive compounds (phytochemicals) that positively affect human and animal health. Herein, this work aimed to examine a standardized chemical composition and screen the antimicrobial and anti-biofilm activity of Thymus sibthorpii, Origanum vulgare, Salvia fruticosa, and Crithmum maritimum EOs against three different Staphylococcus aureus strains by gold-standard disc diffusion, broth microdilution, and microtiter plate biofilm assays. Therefore, the evaluation of the above-mentioned EOs were considered as substitutes for antibiotics to combat the ever-mounting antimicrobial resistance problem. The observed bacterial growth inhibition varied significantly depending on the type and concentration of the antimicrobials. Thymus sibthorpii was determined as the strongest antimicrobial, with 0.091 mg/mL minimum inhibitory concentration (MIC) and a 14-33 mm diameter inhibition zone at 5% (v/v) concentration. All tested EOs indicated almost 95% inhibition of biofilm formation at their half MIC, while gentamicin sulfate did not show sufficient anti-biofilm activity. None of the methicillin-resistant strains showed resistance to the EOs compared to methicillin-sensitive strains. Thymus sibthorpii and Origanum vulgare could be potential alternatives as antimicrobial agents to overcome the problem of microbial resistance. The tested EOs might be incorporated into antimicrobial products as safe and potent antimicrobial and anti-biofilm agents.}, } @article {pmid36830264, year = {2023}, author = {Baltogianni, M and Giapros, V and Kosmeri, C}, title = {Antibiotic Resistance and Biofilm Infections in the NICUs and Methods to Combat It.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830264}, issn = {2079-6382}, abstract = {Neonatal sepsis is an important cause of neonatal morbidity and mortality. A significant proportion of bacteria causing neonatal sepsis is resistant to multiple antibiotics, not only to the usual empirical first-line regimens, but also to second- and third-line antibiotics in many neonatal intensive care units (NICUs). NICUs have unique antimicrobial stewardship goals. Apart from antimicrobial resistance, NICUs have to deal with another problem, namely biofilm infections, since neonates often have central and peripheral lines, tracheal tubes and other foreign bodies for a prolonged duration. The aim of this review is to describe traditional and novel ways to fight antibiotic-resistant bacteria and biofilm infections in NICUs. The topics discussed will include prevention and control of the spread of infection in NICUs, as well as the wise use of antimicrobial therapy and ways to fight biofilm infections.}, } @article {pmid36830260, year = {2023}, author = {Kim, YM and Son, H and Park, SC and Lee, JK and Jang, MK and Lee, JR}, title = {Anti-Biofilm Effects of Rationally Designed Peptides against Planktonic Cells and Pre-Formed Biofilm of Pseudomonas aeruginosa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830260}, issn = {2079-6382}, support = {NRF-2016R1D1A3A03918533//Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology/ ; NIE-A-2023-07//National Institute of Ecology (NIE), funded by the Ministry of Environment (MOE) of Korea/ ; }, abstract = {Biofilms are resistant to antibiotics and are a major source of persistent and recurring infections by clinically important pathogens. Drugs used for biofilm-associated infections are limited because biofilm-embedded or biofilm-matrix bacteria are difficult to kill or eradiate. Therefore, many researchers are developing new and effective antibiofilm agents. Among them, antimicrobial peptides have an attractive interest in the development of antibiofilm agents. The present study evaluated the effects of 10 synthetic peptides on growth inhibition, inhibition of biofilm formation, and biofilm elimination in drug-resistant Pseudomonas aeruginosa. The planktonic cell growth and biofilm formation were dose-dependently inhibited by most of the peptides. WIK-14 eliminated preformed biofilm masses by removing carbohydrates, extracellular nucleic acids, proteins, and lipids constituting extracellular polymeric substances. The results demonstrated that WIK-14 and WIKE-14 peptides might provide novel therapeutic drugs to overcome multidrug resistance in biofilm-associated infections.}, } @article {pmid36830240, year = {2023}, author = {Ribeiro, SM and Bueno, PCP and Cavalheiro, AJ and Klein, MI}, title = {Effect of Extracts, Fractions, and Isolated Molecules of Casearia sylvestris to Control Streptococcus mutans Cariogenic Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830240}, issn = {2079-6382}, support = {2019/23175-7 and 2011/21440-3//São Paulo Research Foundation/ ; Finance Code 001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {The effects of extracts, fractions, and molecules of Casearia sylvestris to control the cariogenic biofilm of Streptococcus mutans were evaluated. First, the antimicrobial and antibiofilm (initial and pre-formed biofilms) in prolonged exposure (24 h) models were investigated. Second, formulations (with and without fluoride) were assessed for topical effects (brief exposure) on biofilms. Third, selected treatments were evaluated via bacterium growth inhibition curves associated with gene expression and scanning electron microscopy. In initial biofilms, the ethyl acetate (AcOEt) and ethanolic (EtOH) fractions from Brasília (BRA/DF; 250 µg/mL) and Presidente Venceslau/SP (Water/EtOH 60:40 and Water/EtOH 40:60; 500 µg/mL) reduced ≥6-logs vs. vehicle. Only the molecule Caseargrewiin F (CsF; 125 µg/mL) reduced the viable cell count of pre-formed biofilms (5 logs vs. vehicle). For topical effects, no formulation affected biofilm components. For the growth inhibition assay, CsF yielded a constant recovery of surviving cells (≅3.5 logs) until 24 h (i.e., bacteriostatic), and AcOEt_BRA/DF caused progressive cell death, without cells at 24 h (i.e., bactericidal). CsF and AcOEt_BRA/DF damaged S. mutans cells and influenced the expression of virulence genes. Thus, an effect against biofilms occurred after prolonged exposure due to the bacteriostatic and/or bactericidal capacity of a fraction and a molecule from C. sylvestris.}, } @article {pmid36830229, year = {2023}, author = {Senneville, E and Gachet, B and Blondiaux, N and Robineau, O}, title = {Do Anti-Biofilm Antibiotics Have a Place in the Treatment of Diabetic Foot Osteomyelitis?.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830229}, issn = {2079-6382}, abstract = {The choice of antibiotic regimens for use in patients presenting with diabetic foot osteomyelitis and their duration differs according to the situation. Antibiotics play a more important role in the medical option where no infected bone has been resected, while their role is reduced but not negligible in the case of surgical options. Some studies have reported the presence of biofilm structures in bone samples taken from patients with diabetic foot osteomyelitis, which raises the question of the place of anti-biofilm antibiotic regimens in this setting. During the last two decades, clinical studies have suggested a potential benefit for anti-biofilm antibiotics, mainly rifampicin against staphylococci and fluoroquinolones against gram-negative bacilli. However, no data from randomized controlled studies have been reported so far. The present work provides a summary of the available data on the question of the place of anti-biofilm antibiotics for the treatment of diabetic foot osteomyelitis, but also the potential limitations of such treatments.}, } @article {pmid36830210, year = {2023}, author = {Shamim, A and Ali, A and Iqbal, Z and Mirza, MA and Aqil, M and Kawish, SM and Siddiqui, A and Kumar, V and Naseef, PP and Alshadidi, AAF and Saheer Kuruniyan, M}, title = {Natural Medicine a Promising Candidate in Combating Microbial Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830210}, issn = {2079-6382}, support = {RGP 2/218/43//King Khalid University/ ; }, abstract = {Studies on biofilm-related infections are gaining prominence owing to their involvement in most clinical infections and seriously threatening global public health. A biofilm is a natural form of bacterial growth ubiquitous in ecological niches, considered to be a generic survival mechanism adopted by both pathogenic and non-pathogenic microorganisms and entailing heterogeneous cell development within the matrix. In the ecological niche, quorum sensing is a communication channel that is crucial to developing biofilms. Biofilm formation leads to increased resistance to unfavourable ecological effects, comprising resistance to antibiotics and antimicrobial agents. Biofilms are frequently combated with modern conventional medicines such as antibiotics, but at present, they are considered inadequate for the treatment of multi-drug resistance; therefore, it is vital to discover some new antimicrobial agents that can prevent the production and growth of biofilm, in addition to minimizing the side effects of such therapies. In the search for some alternative and safe therapies, natural plant-derived phytomedicines are gaining popularity among the research community. Phytomedicines are natural agents derived from natural plants. These plant-derived agents may include flavonoids, terpenoids, lectins, alkaloids, polypeptides, polyacetylenes, phenolics, and essential oils. Since they are natural agents, they cause minimal side effects, so could be administered with dose flexibility. It is vital to discover some new antimicrobial agents that can control the production and growth of biofilms. This review summarizes and analyzes the efficacy characteristics and corresponding mechanisms of natural-product-based antibiofilm agents, i.e., phytochemicals, biosurfactants, antimicrobial peptides, and their sources, along with their mechanism, quorum sensing signalling pathways, disrupting extracellular matrix adhesion. The review also provides some other strategies to inhibit biofilm-related illness. The prepared list of newly discovered natural antibiofilm agents could help in devising novel strategies for biofilm-associated infections.}, } @article {pmid36830203, year = {2023}, author = {Moshynets, OV and Baranovskyi, TP and Iungin, OS and Krikunov, AA and Potochilova, VV and Rudnieva, KL and Potters, G and Pokholenko, I}, title = {Therapeutic Potential of an Azithromycin-Colistin Combination against XDR K. pneumoniae in a 3D Collagen-Based In Vitro Wound Model of a Biofilm Infection.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830203}, issn = {2079-6382}, support = {2020.02/0246//National Research Foundation of Ukraine/ ; }, abstract = {A therapeutic combination of azithromycin (AZM) and colistin methanesulfonate (CMS) was shown to be effective against both non-PDR and PDR Klebsiella pneumoniae biofilms in vitro. These anti-biofilm effects, however, may not correlate with effects observed in standard plate assays, nor will they representative of in vivo therapeutic action. After all, biofilm-associated infection processes are also impacted by the presence of wound bed components, such as host cells or wound fluids, which can all affect the antibiotic effectiveness. Therefore, an in vitro wound model of biofilm infection which partially mimics the complex microenvironment of infected wounds was developed to investigate the therapeutic potential of an AZM-CMS combination against XDR K. pneumoniae isolates. The model consists of a 3D collagen sponge-like scaffold seeded with HEK293 cells submerged in a fluid milieu mimicking the wound bed exudate. Media that were tested were all based on different strengths of Dulbecco's modified Eagles/high glucose medium supplemented with fetal bovine serum, and/or Bacto Proteose peptone. Use of this model confirmed AZM to be a highly effective antibiofilm component, when applied alone or in combination with CMS, whereas CMS alone had little antibacterial effectiveness or even stimulated biofilm development. The wound model proposed here proves therefore, to be an effective aid in the study of drug combinations under realistic conditions.}, } @article {pmid36830150, year = {2023}, author = {Farha, AK and Sui, Z and Corke, H}, title = {Raspberry Ketone-Mediated Inhibition of Biofilm Formation in Salmonella enterica Typhimurium-An Assessment of the Mechanisms of Action.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830150}, issn = {2079-6382}, support = {8211101469//National Natural Science Foundation of China/ ; 2017YFC1600100//National Key R&D Program of China/ ; }, abstract = {Salmonella enterica is an important foodborne pathogen that causes gastroenteritis and systemic infection in humans and livestock. Salmonella biofilms consist of two major components-amyloid curli and cellulose-which contribute to the prolonged persistence of Salmonella inside the host. Effective agents for inhibiting the formation of biofilms are urgently needed. We investigated the antibiofilm effect of Raspberry Ketone (RK) and its mechanism of action against Salmonella Typhimurium 14028 using the Congo red agar method, Calcofluor staining, crystal violet method, pellicle assay, and the TMT-labeled quantitative proteomic approach. RK suppressed the formation of different types of Salmonella biofilms, including pellicle formation, even at low concentrations (200 µg/mL). Furthermore, at higher concentrations (2 mg/mL), RK exhibited bacteriostatic effects. RK repressed cellulose deposition in Salmonella biofilm through an unknown mechanism. Swimming and swarming motility analyses demonstrated reduced motility in RK-treated S. typhimurium. Proteomics analysis revealed that pathways involved in amyloid curli production, bacterial invasion, flagellar motility, arginine biosynthesis, and carbohydrate metabolism, were targeted by RK to facilitate biofilm inhibition. Consistent with the proteomics data, the expressions of csgB and csgD genes were strongly down-regulated in RK-treated S. typhimurium. These findings clearly demonstrated the Salmonella biofilm inhibition capability of RK, justifying its further study for its efficacy assessment in clinical and industrial settings.}, } @article {pmid36830146, year = {2023}, author = {Miłek, M and Ciszkowicz, E and Sidor, E and Hęclik, J and Lecka-Szlachta, K and Dżugan, M}, title = {The Antioxidant, Antibacterial and Anti-Biofilm Properties of Rapeseed Creamed Honey Enriched with Selected Plant Superfoods.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830146}, issn = {2079-6382}, support = {PB/ZCHTZ/2022//Ministry of Science and Higher Education/ ; }, abstract = {The aim of the study is to evaluate the effect of the addition of selected fruits and herbs belonging to the "superfoods" category for the bioactivity of a rapeseed honey matrix. Flavored creamed honeys with nine types of various additives (2 and 4% of content) were prepared and analyzed for the content of total phenols, flavonoids, antioxidant (FRAP, DPPH and ABTS) and antibacterial activity against four strains of bacteria. Additionally, the impact of three months of storage on the antioxidant properties of the products obtained was examined. The significant dose-dependent increase in the content of bioactive ingredients and antioxidant capacity in spiced honeys, as compared to control honey, was observed. The highest enrichment was obtained for the addition of powdered sea buckthorn leaves and black raspberry fruits. Honey with the addition of sea buckthorn leaves inhibited the growth of P. aeruginosa, S. aureus and K. pneumonia, whereas honeys with black raspberry and blackcurrant fruits showed activity only on the latter two strains. Furthermore, what is more interesting, honey supplemented with sea buckthorn leaf and black raspberry fruits inhibited S. aureus biofilm formation at the sub-minimum inhibitory concentrations (sub-MICs), showing a dose-dependent anti-biofilm effect.}, } @article {pmid36830100, year = {2023}, author = {Amábile-Cuevas, CF}, title = {Macrolides at Clinically-Relevant Concentrations May Induce Biofilm Formation in Macrolide-Resistant Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {36830100}, issn = {2079-6382}, abstract = {Macrolides inhibit biofilm formation in several Gram-negative, intrinsically-resistant bacterial species. However, the effect of macrolides upon biofilm formation by susceptible Gram-positive bacteria has been much less explored as such concentrations also inhibit cell growth. To circumvent this problem, the effect of macrolides (erythromycin, clarithromycin and azithromycin) at 0.5-2 µg/mL, upon biofilm formation, was explored on macrolide-resistant Staphylococcus aureus isolates, using the crystal violet assay with 96-well plates. Early (4 h) biofilm formation by strains having constitutive target-modification resistance was consistently induced by all macrolides but not in azithromycin-treated cells in longer (8 and 12 h) incubation. In inducible-resistance isolates, early biofilm formation was enhanced by some macrolide treatments, compared to similar cell growth in the absence of antibiotics; but the typical decay of biofilms at longer incubation appeared prematurely in macrolide-treated cultures. Biofilm formation in an efflux-mediated resistant isolate was not affected by macrolides. These results indicate that macrolides induce the formation of biofilm by resistant S. aureus isolates, especially during the early stages. This suggests that the empirical use of macrolides against infections caused by resistant S. aureus strains could not only result in clinical failure but even in the enhancement of biofilms, making further treatment difficult.}, } @article {pmid36828058, year = {2023}, author = {Yuan, S and Guo, S and Tan, Y and Li, M and Lu, Y and Xu, R and Tawfik, A and Zhou, Z and Chen, J and Liu, W and Meng, F}, title = {Deciphering community assembly and succession in sequencing batch moving bed biofilm reactor: Differentiation between attached and suspended communities.}, journal = {The Science of the total environment}, volume = {873}, number = {}, pages = {162448}, doi = {10.1016/j.scitotenv.2023.162448}, pmid = {36828058}, issn = {1879-1026}, mesh = {*Ecosystem ; *Biofilms ; Biomass ; Nitrification ; Bacteria ; Bioreactors ; }, abstract = {Elucidating community assembly and succession is crucial to understanding the ecosystem functioning. Herein, the ecological processes underpinning community assembly and succession were studied to uncover the respective ecological functions of attached biofilms and suspended biomass in a sequencing batch moving bed biofilm reactor. Compared with suspended biomass, attached biofilms presented higher relative abundances of Nitrospira (2.94 %) and Nitrosomonas (1.25 %), and contributed to 66.89 ± 11.37 % and 68.11 ± 12.72 % of nitrification and denitrification activities, respectively. The microbial source tracking result demonstrated that early formation of suspended biomass was dominated by the seeding effect of detached biofilms in the start-up period (days 0-30), while self-growth of previous suspended biomass was eventually outcompeted the seeding effect when the reactor stabilized (days 31-120). Null model and ecological network analysis further suggested distinctive ecological processes underpinning the differentiation between attached and suspended communities in the same reactor. Specifically, in the start-up period, positive interactions facilitated early formation of attached (73.84 %) and suspended communities (59.41 %), while homogenous selection (88.89 %) and homogenizing dispersal (65.71 %) governed assembly of attached and suspended communities, respectively. When the reactor stabilized, attached and suspended communities showed low composition turnover as reflected by dominant homogenizing dispersal, while they presented distinctive trends of interspecies interactions. This study sheds light on discrepant ecological processes governing community differentiation of attached biofilms and suspended biomass, which would provide ecological insights into the regulation of hybrid ecosystems.}, } @article {pmid36826286, year = {2023}, author = {Pessanha, FS and Oliveira, BGRB and Oliveira, BC and Deutsch, G and Teixeira, FL and Bokehi, LC and Calomino, MA and Rodrigues de Castilho, S and Thiré, RMDSM and Teixeira, LA and Paula, GR}, title = {Effectiveness of Epidermal Growth Factor Loaded Carboxymethylcellulose (EGF-CMC) Hydrogel in Biofilm Formation in Wounds of Diabetic Patients: A Randomized Clinical Trial.}, journal = {Gels (Basel, Switzerland)}, volume = {9}, number = {2}, pages = {}, pmid = {36826286}, issn = {2310-2861}, support = {PhD grant (Deutsch G)//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; MSc grant (Oliveira BC)//National Council for Scientific and Technological Development/ ; }, abstract = {Diabetic patients frequently develop wounds, which can be colonized by bacteria, mainly Staphylococcus aureus and Pseudomonas aeruginosa, with the ability to form biofilms. This study aimed to evaluate the colonization and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa in chronic wounds of diabetic patients treated with a bioactive dressing (EGF-CMC), which consisted of a 2% carboxymethylcellulose (CMC) hydrogel loaded with epidermal growth factor (EGF). This randomized clinical trial was conducted with 25 participants: 14 treated with EGF-CMC hydrogel and 11 treated with CMC hydrogel for 12 weeks. Participants with type 2 diabetes mellitus were selected. All had diabetic foot ulcers or chronic venous ulcers. Swab collections were performed on weeks 1, 6, and 12. The laboratory analyses included the identification of strains, microbial quantification, virulence gene investigation, and the evaluation of biofilm formation. In total, 13 S. aureus strains and 15 P. aeruginosa strains were isolated. There were no statistically significant differences regarding bacterial loads and virulence genes. However, EGF-CMC-hydrogel-treated wounds were colonized by strains with lower biofilm formation abilities. The probability of isolating biofilm-producing strains from CMC-hydrogel-treated wounds was 83% greater than the probability of isolating biofilm-producing strains from EGF-CMC-treated wounds.}, } @article {pmid36825362, year = {2023}, author = {Park, EH and Park, R and Seo, J and Kim, W and Kim, HY and Shon, WJ}, title = {Efficacy of a novel remotely-generated ultrasonic root canal irrigation system for removing biofilm-mimicking hydrogel from a simulated isthmus model.}, journal = {International endodontic journal}, volume = {56}, number = {6}, pages = {765-774}, doi = {10.1111/iej.13905}, pmid = {36825362}, issn = {1365-2591}, support = {HI18C0432//Ministry of Health & Welfare, Republic of Korea/ ; 2021R1A1A03039462//National Research Foundation of Korea (NRF)/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Hydrogels ; Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Therapeutic Irrigation/methods ; *Ultrasonics ; }, abstract = {AIM: To evaluate the efficacy of a novel ultrasonic irrigation device, remotely-generated irrigation with a non-invasive sound field enhancement (RINSE) system, in removing biofilm-mimicking hydrogel from a simulated isthmus model and compare it with sonically- and ultrasonically-activated irrigation systems.

METHODOLOGY: A polycarbonate root canal model containing two standardized root canals (apical diameter of 0.20 mm, 4% taper, 18 mm long with a coronal reservoir) connected by three isthmuses (0.40 mm deep, 2 mm high, 4 mm long) was used as the test model. The isthmuses were filled with a hydroxyapatite powder-containing hydrogel. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n = 15): EndoActivator (EA), ultrasonically activated irrigation (UAI), and RINSE system (RS). Syringe irrigation (SI) with a 30G needle served as the control. Standardized images of the isthmuses were taken before and after irrigation, and the amount of hydrogel removed was determined using image analysis software and compared across groups using anova (p < .05).

RESULTS: Hydrogel removal was significantly higher with the RS (83.7%) than with UAI, EA, or SI (p ≤ .01). UAI (69.2%) removed significantly more hydrogel than SI and EA (p < .05), while there was no significant difference between SI (24.3%) and EA (25.7%) (p = .978).

CONCLUSIONS: RINSE system resulted in the most hydrogel removal, performing better than UAI or EA. The effect of RS was also not reliant on the insert or tip entering the pulp chamber or root canal, making it particularly useful in conservative endodontics.}, } @article {pmid36824979, year = {2023}, author = {Evans, CR and Smiley, MK and Thio, SA and Wei, M and Price-Whelan, A and Min, W and Dietrich, LEP}, title = {Spatial heterogeneity in biofilm metabolism elicited by local control of phenazine methylation.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36824979}, abstract = {UNLABELLED: Within biofilms, gradients of electron acceptors such as oxygen stimulate the formation of physiological subpopulations. This heterogeneity can enable cross-feeding and promote drug resilience, features of the multicellular lifestyle that make biofilm-based infections difficult to treat. The pathogenic bacterium Pseudomonas aeruginosa produces pigments called phenazines that can support metabolic activity in hypoxic/anoxic biofilm subzones, but these compounds also include methylated derivatives that are toxic to their producer under some conditions. Here, we uncover roles for the global regulators RpoS and Hfq/Crc in controlling the beneficial and detrimental effects of methylated phenazines in biofilms. Our results indicate that RpoS controls phenazine methylation by modulating activity of the carbon catabolite repression pathway, in which the Hfq/Crc complex inhibits translation of the phenazine methyltransferase PhzM. We find that RpoS indirectly inhibits expression of CrcZ, a small RNA that binds to and sequesters Hfq/Crc, specifically in the oxic subzone of P. aeruginosa biofilms. Deletion of rpoS or crc therefore leads to overproduction of methylated phenazines, which we show leads to increased metabolic activity-an apparent beneficial effect-in hypoxic/anoxic subpopulations within biofilms. However, we also find that biofilms lacking Crc show increased sensitivity to an exogenously added methylated phenazine, indicating that the increased metabolic activity in this mutant comes at a cost. Together, these results suggest that complex regulation of PhzM allows P. aeruginosa to simultaneously exploit the benefits and limit the toxic effects of methylated phenazines.

SIGNIFICANCE STATEMENT: P. aeruginosa causes biofilm-based infections and is known for its production of colorful phenazine derivatives. Among these the methylated phenazines are the most toxic and can cause condition-dependent damage to their producer. In this study, we show that methylated phenazines also have a beneficial effect in that they specifically support metabolic activity at depth in P. aeruginosa biofilms, where oxygen limitation would otherwise stall metabolism. We describe a new link between P. aeruginosa global regulators that control methylated phenazine production in a manner that limits their toxicity while simultaneously enabling their contribution to metabolism. These results expand our understanding of the strategies that enable P. aeruginosa survival in multicellular structures, which is key to its success during chronic host colonization.}, } @article {pmid36824891, year = {2023}, author = {Pastar, I and Dinic, M and Verpile, R and Meng, J and Marjanovic, J and Burgess, J and Plano, L and Hower, S and Thaller, S and Banerjee, S and Lev-Tov, H and Tomic-Canic, M}, title = {Chronic wound microenvironment mediates selection of biofilm-forming multi drug resistant Staphylococcus epidermidis with capability to impair healing.}, journal = {Research square}, volume = {}, number = {}, pages = {}, pmid = {36824891}, support = {F30 DK132806/DK/NIDDK NIH HHS/United States ; }, abstract = {Venous leg ulcers (VLU) are the most common chronic wounds characterized by bacterial biofilms and perturbed microbiome. Staphylococcus epidermidis is primarily known as skin commensal beneficial for the host, however, some strains can form biofilms and cause infections. By employing shotgun metagenomic sequencing we show that genetic signatures of antimicrobial resistance, adhesion and biofilm formation in VLU isolates correlate with in vitro bacterial traits. We demonstrate that the capability of chronic wound isolates to form biofilms and elicit IL-8 and IL-1β expression in human ex vivo wounds, correlates with the non-healing outcomes in patients with VLU. In contrast, commensal strains were incapable of surviving in the human ex vivo wounds. We show that major fitness traits of S. epidermis from VLU involve genes for resistance to methicillin and mupirocin, while the biofilm formation relied on the minimal number of genetic elements responsible for bacterial binding to fibronectin and fibrinogen. This underscores the importance of the emergence of treatment resistant virulent lineages in patients with non-healing wounds.}, } @article {pmid36824066, year = {2023}, author = {Dan, B and Dai, H and Zhou, D and Tong, H and Zhu, M}, title = {Relationship Between Drug Resistance Characteristics and Biofilm Formation in Klebsiella Pneumoniae Strains.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {985-998}, pmid = {36824066}, issn = {1178-6973}, abstract = {OBJECTIVE: To conduct epidemiological analysis of Klebsiella pneumoniae (K. pneumoniae) with hypervirulence, and to investigate its drug resistance phenotype, Extended-spectrum β-lactamase (ESBLs) gene, virulence factor, capsular serotype and biofilm formation, so as to provide theoretical basis for further understanding of the drug resistance mechanism of K. pneumoniae with hypervirulence.

METHODS: K. Pneumoniae were isolated from clinical samples collected from inpatients. All strains were identified by VITEK2 Compact using fully automatic microbial analyzer, the minimal inhibitory concentration (MIC) of antibiotics was determined by microbroth dilution test. The double disk diffusion method was used to detect the production of ESBLs, modified carbapenem inactivation method (mCIM) was used to detect the production of carbapenemase, and hypermucoviscosity phenotype was detected by wire drawing test. PCR was used to detect ESBLs gene, virulence factor and capsular serotype. Crystal violet staining was used to detect the ability of biofilm formation.

RESULTS: The ESBLs genes detected in this study included strains blaTEM 35 (36.5%), blaSHV 51 (53.1%), and blaCTX-M 49 (51.0%). Most strains carried multiple ESBLs genes, but not all of them produce ESBLs. K1 and K2 accounted for 14.6% and 11.5% respectively. Most (91.7%) strains carried the fimH gene, and the other virulence genes were ybtS (53.1%), entB (46.9%), rmpA (41.7%), aerobactin (32.3%), allS (15.6%), kfu (15.6%). Of all the Klebsiella pneumoniae strains, 33 (34.4%) exhibited ESBLs phenotype, 16 (16.7%) were carbapenemase-producing, and 20 (20.8%) with ESBLs phenotype tested were resistant to all four drugs. The correlation between ESBLs-producing strains and biofilm formation was significantly increased compared to strains without ESBLs phenotype (P=0.035).

CONCLUSION: Compared to hypervirulent Klebsiella pneumoniae (hvKP), classical Klebsiella pneumoniae (cKP) has a tendency to acquire antibiotic resistance. Our study showed that genes encoding rmpA, K1 or K2, and kfu were highly associated with hvKP.}, } @article {pmid36822111, year = {2023}, author = {Wang, J and Dong, C and Li, Q and Yang, X and Li, D and Zhang, L and Zhang, Y and Zhan, G}, title = {Innovative electrochemical biosensor with nitrifying biofilm and nitrite oxidation signal for comprehensive toxicity detection in Tuojiang River.}, journal = {Water research}, volume = {233}, number = {}, pages = {119757}, doi = {10.1016/j.watres.2023.119757}, pmid = {36822111}, issn = {1879-2448}, mesh = {Biofilms ; *Biosensing Techniques ; *Environmental Monitoring/methods ; Nitrification ; Rivers/chemistry ; Trichloroacetic Acid/analysis/toxicity ; Triclosan/analysis/toxicity ; *Water Pollutants, Chemical/analysis/toxicity ; China ; }, abstract = {Water toxicity detection, as a valuable supplement to conventional water quality measurement, is an important method for evaluating water environmental quality standards. However, the toxicity of composite pollutants is more complicated due to their mixture effects. This study developed a novel, rapid and interference-resistant detection method for water toxicity based on an electrochemical biosensor using peak current from nitrite oxidation as a signal. Toxicants could weaken the characteristic peak current of nitrite to indicate the magnitude of toxicity. The proof-of-concept study was first conducted using a synthetic water sample containing trichloroacetic acid (TCAA), and then the results were compared with those of the traditional toxicity colorimetric method (CCK-8 kit) and laser confocal microscopy (CLSM). The accuracy of the biosensor was further verified with water samples containing individual pollutants such as Cd[2+] (50-150 μg/L), Cr[6+] (20-80 μg/L) mixture, triclosan (TCS; 0.1-1.0 μg/L) and TCAA (10-80 μg/L), or a mixture of the above. The viability of the sensor was further validated with the actual water sample from the Tuojiang River. The results demonstrated that although the concentration of a single conventional pollutant in water did not exceed the discharge standard for surface water, the comprehensive toxicity of natural water should not be ignored. This method could be a beneficial supplement to conventional water quality detection to understand the characteristics of the water, and thus contribute to the next stage of water treatment.}, } @article {pmid36820892, year = {2023}, author = {Krishnan, A and Rajendran, R and Damodaran, D and Manmadhan, SK and Krishnan, V}, title = {Long-term changes in thickness, live/dead bacterial ratio, and mineral content in biofilm on ceramic and stainless steel orthodontic attachments.}, journal = {Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie}, volume = {}, number = {}, pages = {}, pmid = {36820892}, issn = {1615-6714}, abstract = {PURPOSE: Fixed orthodontic appliances induce biofilm deposition, which harbors a microbial population harmful to the periodontal health of the individual. The present study evaluated the changes in thickness, live/dead bacterial ratio, and mineral content in dental biofilm over 6 months in patients with either stainless steel or ceramic orthodontic attachments.

METHODS: Eighty patients who require fixed orthodontic appliance treatment with first premolar extraction for correcting their malocclusion were selected and bonded with either stainless steel or ceramic orthodontic attachments on the buccal side. The attached buttons were retrieved at different periods-1 week, 1 month, 3 months, and 6 months. They were stained and visualized through confocal microscopy to detect biofilm thickness and the ratio of live/dead bacteria. X‑ray diffraction was used to identify the presence of calcium and phosphorous.

RESULTS: Ceramic attachments showed a greater increase in biofilm thickness in comparison to stainless steel attachments except in the initial 1‑week evaluation. A higher live/dead bacterial ratio was observed in stainless steel attachments than in their ceramic counterparts at all four evaluation periods. Both stainless steel and ceramic surfaces exhibited the presence of mineral deposition (calcium and phosphorous) at all periods.

CONCLUSIONS: More biofilm adhesion was observed over ceramic surfaces than over stainless steel orthodontic attachments. Stainless steel attachments exhibited biofilm with a higher live/dead bacterial ratio than their ceramic counterparts at all evaluation periods. The presence of calcium and phosphorous in the adhered biofilm, pointing toward its calcification process, was identified.}, } @article {pmid36819639, year = {2023}, author = {Haniastuti, T and Puspasari, TA and Hakim, ER and Tandelilin, RT}, title = {Potential Effect of Giant Freshwater Prawn Shell Nano Chitosan in Inhibiting the Development of Streptococcus mutans and Streptococcus sanguinis Biofilm In Vitro.}, journal = {International journal of dentistry}, volume = {2023}, number = {}, pages = {8890750}, pmid = {36819639}, issn = {1687-8728}, abstract = {An oral biofilm comprises a variety of bacteria including Streptococcus mutans and Streptococcus sanguinis that cause human infections, such as caries and periodontitis. Thus, biofilm management plays an important part in the prevention and treatment of oral diseases. Nano chitosan is a bioactive material that has antimicrobial activities. This in vitro study aimed to evaluate the effect of nano chitosan synthesized from giant freshwater prawn shells (PSNC) on S. mutans and S. sanguinis biofilm development. PSNC was prepared from the extracted chitosan of giant freshwater prawn (Macrobrachium rosenbergii) shells using the ionic gelation method. The effect of PSNC on S. mutans ATCC 25175 and S. sanguinis ATCC10556 biofilm formation was evaluated using the crystal violet assay. Both bacteria were inoculated in the presence of various concentrations (5, 2.5, and 1.25 mg/ml) of PSNC for 24 h and 48 h. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy were performed to visualize and study the biofilm architectural features. The biofilms were stained with the BacLight Bacterial Viability Kit prior to CLSM observation to monitor the viability of the biofilm. The results showed that PSNC exposure for 24 h and 48 h inhibited the formation of S. mutans and S. sanguinis biofilms. The biofilm formation inhibition percentage increased with an increase in the PSNC concentration (p < 0.05). The highest inhibitory activity was shown at 5 mg/ml PSNC (p < 0.05). Those findings were confirmed by the subsequent findings using the CLSM and SEM analyses. The biofilm architecture was strongly disrupted upon treatment with PSNC. After exposure to 5 mg/ml PSNC, the number of bacteria significantly decreased. The remaining bacteria were seen as individual cells, showing damaged cells. In conclusion, PSNC inhibits the development of S. mutans and S. sanguinis biofilm in vitro, indicating the potential of PSNC in clinical application for oral bacterial infection, prevention, and treatment.}, } @article {pmid36819068, year = {2023}, author = {Nuppunen-Puputti, M and Kietäväinen, R and Kukkonen, I and Bomberg, M}, title = {Implications of a short carbon pulse on biofilm formation on mica schist in microcosms with deep crystalline bedrock groundwater.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1054084}, pmid = {36819068}, issn = {1664-302X}, abstract = {Microbial life in the deep subsurface occupies rock surfaces as attached communities and biofilms. Previously, epilithic Fennoscandian deep subsurface bacterial communities were shown to host genetic potential, especially for heterotrophy and sulfur cycling. Acetate, methane, and methanol link multiple biogeochemical pathways and thus represent an important carbon and energy source for microorganisms in the deep subsurface. In this study, we examined further how a short pulse of low-molecular-weight carbon compounds impacts the formation and structure of sessile microbial communities on mica schist surfaces over an incubation period of ∼3.5 years in microcosms containing deep subsurface groundwater from the depth of 500 m, from Outokumpu, Finland. The marker gene copy counts in the water and rock phases were estimated with qPCR, which showed that bacteria dominated the mica schist communities with a relatively high proportion of epilithic sulfate-reducing bacteria in all microcosms. The dominant bacterial phyla in the microcosms were Proteobacteria, Firmicutes, and Actinobacteria, whereas most fungal genera belonged to Ascomycota and Basidiomycota. Dissimilarities between planktic and sessile rock surface microbial communities were observed, and the supplied carbon substrates led to variations in the bacterial community composition.}, } @article {pmid36817722, year = {2023}, author = {Mohamed, A and Raval, YS and Gelston, S and Tibbits, G and Ay, SU and Flurin, L and Greenwood-Quaintance, KE and Patel, R and Beyenal, H}, title = {Anti-Biofilm Activity of a Tunable Hypochlorous Acid-Generating Electrochemical Bandage Controlled By a Wearable Potentiostat.}, journal = {Advanced engineering materials}, volume = {25}, number = {1}, pages = {}, pmid = {36817722}, issn = {1438-1656}, support = {R01 AI091594/AI/NIAID NIH HHS/United States ; }, abstract = {Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic-resistant microorganisms and biofilm-specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. We designed an HOCl-generating electrochemical bandage (e-bandage) that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. We developed a battery-operated wearable potentiostat that controls the e-bandage electrodes at potentials suitable for HOCl generation. We demonstrated that e-bandage treatment was tunable by changing the applied potential. HOCl generation on electrode surfaces was verified using microelectrodes. The developed e-bandage showed time-dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to non-detectable levels within 6 and 12 hours of treatment, respectively. The developed e-bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections.}, } @article {pmid36816581, year = {2023}, author = {Parga, A and Muras, A and Otero-Casal, P and Arredondo, A and Soler-Ollé, A and Àlvarez, G and Alcaraz, LD and Mira, A and Blanc, V and Otero, A}, title = {The quorum quenching enzyme Aii20J modifies in vitro periodontal biofilm formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1118630}, pmid = {36816581}, issn = {2235-2988}, mesh = {Humans ; *Quorum Sensing ; Biofilms ; Bacteria/metabolism ; Acyl-Butyrolactones/metabolism ; *Periodontal Diseases ; }, abstract = {INTRODUCTION: Recent studies have revealed the presence of N-acyl-homoserine lactones (AHLs) quorum sensing (QS) signals in the oral environment. Yet, their role in oral biofilm development remains scarcely investigated. The use of quorum quenching (QQ) strategies targeting AHLs has been described as efficient for the control of pathogenic biofilms. Here, we evaluate the use of a highly active AHL-targeting QQ enzyme, Aii20J, to modulate oral biofilm formation in vitro.

METHODS: The effect of the QQ enzyme was studied in in vitro multispecies biofilms generated from oral samples taken from healthy donors and patients with periodontal disease. Subgingival samples were used as inocula, aiming to select members of the microbiota of the periodontal pocket niche in the in vitro biofilms. Biofilm formation abilities and microbial composition were studied upon treating the biofilms with the QQ enzyme Aii20J.

RESULTS AND DISCUSSION: The addition of the enzyme resulted in significant biofilm mass reductions in 30 - 60% of the subgingival-derived biofilms, although standard AHLs could not be found in the supernatants of the cultured biofilms. Changes in biofilm mass were not accompanied by significant alterations of bacterial relative abundance at the genus level. The investigation of 125 oral supragingival metagenomes and a synthetic subgingival metagenome revealed a surprisingly high abundance and broad distribution of homologous of the AHL synthase HdtS and several protein families of AHL receptors, as well as an enormous presence of QQ enzymes, pointing to the existence of an intricate signaling network in oral biofilms that has been so far unreported, and should be further investigated. Together, our findings support the use of Aii20J to modulate polymicrobial biofilm formation without changing the microbiome structure of the biofilm. Results in this study suggest that AHLs or AHL-like molecules affect oral biofilm formation, encouraging the application of QQ strategies for oral health improvement, and reinforcing the importance of personalized approaches to oral biofilm control.}, } @article {pmid36816579, year = {2023}, author = {Sen, P and Gupta, L and Vijay, M and Vermani Sarin, M and Shankar, J and Hameed, S and Vijayaraghavan, P}, title = {4-Allyl-2-methoxyphenol modulates the expression of genes involved in efflux pump, biofilm formation and sterol biosynthesis in azole resistant Aspergillus fumigatus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1103957}, pmid = {36816579}, issn = {2235-2988}, mesh = {*Aspergillus fumigatus/genetics ; *Azoles/pharmacology ; Antifungal Agents/pharmacology ; Eugenol/pharmacology ; Drug Resistance, Fungal ; Biofilms ; Guaiacol/pharmacology ; Sterols/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {INTRODUCTION: Antifungal therapy for aspergillosis is becoming problematic because of the toxicity of currently available drugs, biofilm formation on host surface, and increasing prevalence of azole resistance in Aspergillus fumigatus. Plants are rich source of bioactive molecules and antimicrobial activity of aromatic bioactive compounds draws attention because of its promising biological properties. The present study elucidated the antibiofilm activity of 4-allyl-2-methoxyphenol (eugenol) against azole-resistant environmental A. fumigatus isolates.

METHODS: Soil samples were collected from agricultural fields across India; azole-resistant A. fumigatus (ARAF) were isolated followed by their molecular identification. Antibiofilm activity of eugenol was calculated via tetrazolium based-MTT assay. The expression of the multidrug efflux pumps genes MDR1, MDR4, transporters of the MFS gene, erg11A gene encoding 14α demethylase, and transcription regulatory genes, MedA, SomA and SrbA, involved in biofilm formation of A. fumigatus were calculated by quantitative real time PCR.

RESULTS: Out of 89 A. fumigatus isolates, 10 were identified as azole resistant. Eugenol exhibited antibiofilm activity against ARAF isolates, ranging from 312 to 500 µg/mL. Confocal laser scanning microscopy analysis revealed absence of extracellular matrix of ARAF biofilm after eugenol treatment. The gene expression indicated significantly low expression of efflux pumps genes MDR1, MDR4, erg11A and MedA in eugenol treated ARAF isolates when compared with untreated isolates.

CONCLUSIONS: Our results demonstrate that eugenol effects the expression of efflux pump and biofilm associated genes as well as inhibits biofilm formation in azole resistant isolates of A. fumigatus.}, } @article {pmid36815575, year = {2023}, author = {Ong, J and Godfrey, R and Nazarian, A and Tam, J and Drake, L and Isaacson, B and Pasquina, P and Williams, D}, title = {Antimicrobial blue light as a biofilm management therapy at the skin-implant interface in an ex vivo percutaneous osseointegrated implant model.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {}, number = {}, pages = {}, doi = {10.1002/jor.25535}, pmid = {36815575}, issn = {1554-527X}, support = {HU00011920009//Uniformed Services University of the Health Sciences/ ; }, abstract = {Biofilm contamination is often present at the skin-implant interface of transfemoral osseointegrated implants leading to frequent infection, irritation, and discomfort. New biofilm management regimens are needed as the current standard of washing the site with soap and water is inadequate to manage infection rates. We investigated the potential of antimicrobial blue light, which has reduced risk of resistance development and broad antimicrobial mechanisms. Our lab developed an antimicrobial blue light (aBL) device uniquely designed for an ex vivo system based on an established ovine osseointegrated (OI) implant model with Staphylococcus aureus ATCC 6538 biofilms as initial inocula. Samples were irradiated with aBL or washed for three consecutive days after which they were quantified. Colony-forming unit (CFU) counts were compared with a control group (bacterial inocula without treatment). After 1 day, aBL administered as a single 6 h dose or two 1 h doses spaced 6 h apart both reduced the CFU count by 1.63 log10 ± 0.02 CFU. Over 3 days of treatment, a positive aBL trend was observed with a maximum reduction of ~2.7 log10 CFU following 6 h of treatment, indicating a relation between multiple days of irradiation and greater CFU reductions. aBL was more effective at reducing the biofilm burden at the skin-implant interface compared with the wash group, demonstrating the potential of aBL as a biofilm management option.}, } @article {pmid36812964, year = {2023}, author = {Sun, X and Yu, J and Wei, Q and Ren, X}, title = {Construction of chitosan-based supramolecular biofilm material for wound dressing based on natural deep eutectic solvents.}, journal = {International journal of biological macromolecules}, volume = {236}, number = {}, pages = {123768}, doi = {10.1016/j.ijbiomac.2023.123768}, pmid = {36812964}, issn = {1879-0003}, mesh = {*Chitosan/pharmacology/chemistry ; Deep Eutectic Solvents ; Biocompatible Materials/chemistry ; Solvents/chemistry ; Bandages ; Biofilms ; Escherichia coli ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {Bacterial infection is still one of the main problems observed in the clinical process of wound healing, so the development of new multifunctional biocompatible materials is an urgent clinical need. A kind of supramolecular biofilm crosslinked by hydrogen bond between natural deep eutectic solvent and chitosan was studied and successfully prepared to reduce bacterial infection. Its killing rates of Staphylococcus aureus and Escherichia coli can reach 98.86 % ± 1.90 % and 99.69 % ± 0.53 %, and it can be degraded in both soil and water, showing excellent biocompatibility and biodegradability. In addition, the supramolecular biofilm material also has the UV barrier property, which can effectively avoid the secondary injury of UV to the wound. Interestingly, the cross-linking effect of hydrogen bond makes the biofilm have a more compact structure and rough surface, and gives the biofilm strong tensile properties. Overall, owing to these unique advantages, NADES-CS supramolecular biofilm has great potential for medical applications, laying the foundation for the realization of sustainable polysaccharide materials.}, } @article {pmid36812218, year = {2023}, author = {Gallingani, T and Resca, E and Dominici, M and Gavioli, G and Laurita, R and Liguori, A and Mari, G and Ortolani, L and Pericolini, E and Sala, A and Laghi, G and Petrachi, T and Arnauld, GF and Accorsi, L and Rizzoli, R and Colombo, V and Gherardi, M and Veronesi, E}, title = {A new strategy to prevent biofilm and clot formation in medical devices: The use of atmospheric non-thermal plasma assisted deposition of silver-based nanostructured coatings.}, journal = {PloS one}, volume = {18}, number = {2}, pages = {e0282059}, pmid = {36812218}, issn = {1932-6203}, mesh = {Mice ; Animals ; *Silver/chemistry ; Coated Materials, Biocompatible/chemistry ; *Metal Nanoparticles ; Anti-Bacterial Agents/pharmacology ; Biofilms ; }, abstract = {In industrialized countries, health care associated infections, the fourth leading cause of disease, are a major health issue. At least half of all cases of nosocomial infections are associated with medical devices. Antibacterial coatings arise as an important approach to restrict the nosocomial infection rate without side effects and the development of antibiotic resistance. Beside nosocomial infections, clot formation affects cardiovascular medical devices and central venous catheters implants. In order to reduce and prevent such infection, we develop a plasma-assisted process for the deposition of nanostructured functional coatings on flat substrates and mini catheters. Silver nanoparticles (Ag NPs) are synthesized exploiting in-flight plasma-droplet reactions and are embedded in an organic coating deposited through hexamethyldisiloxane (HMDSO) plasma assisted polymerization. Coating stability upon liquid immersion and ethylene oxide (EtO) sterilization is assessed through chemical and morphological analysis carried out by means of Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In the perspective of future clinical application, an in vitro analysis of anti-biofilm effect has been done. Moreover, we employed a murine model of catheter-associated infection which further highlighted the performance of Ag nanostructured films in counteract biofilm formation. The anti-clot performances coupled by haemo- and cytocompatibility assays have also been performed.}, } @article {pmid36811771, year = {2023}, author = {Ikome, HN and Tamfu, AN and Abdou, JP and Fouotsa, H and Nangmo, PK and Lah, FCW and Tchinda, AT and Ceylan, O and Frederich, M and Nkengfack, AE}, title = {Disruption of Biofilm Formation and Quorum Sensing in Pathogenic Bacteria by Compounds from Zanthoxylum Gilletti (De Wild) P.G. Waterman.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {36811771}, issn = {1559-0291}, abstract = {Microbial resistance is facilitated by biofilm formation and quorum-sensing mediated processes. In this work, the stem bark (ZM) and fruit extracts (ZMFT) of Zanthoxylum gilletii were subjected to column chromatography and afforded lupeol (1), 2,3-epoxy-6,7-methylenedioxyconiferyl alcohol (3), nitidine chloride (4), nitidine (7), sucrose (6) and sitosterol-β-D-glucopyranoside (2). The compounds were characterized using MS and NMR spectral data. The samples were evaluated for antimicrobial, antibiofilm and anti-quorum sensing activities. Highest antimicrobial activity was exhibited by compounds 3, 4 and 7 against Staphylococcus aureus (MIC 200 µg/mL), compounds 3 and 4 against Escherichia coli (MIC = 100 µg/mL) and compounds 4 and 7 against Candida albicans (MIC = 50 µg/mL). At MIC and sub-MIC concentrations, all samples inhibited biofilm formation by pathogens and violacein production in C. violaceum CV12472 except compound 6. Good disruption of QS-sensing in C. violaceum revealed by inhibition zone diameters were exhibited by compounds 3 (11.5 ± 0.5 mm), 4 (12.5 ± 1.5 mm), 5 (15.0 ± 0.8 mm), 7 (12.0 ± 1.5 mm) as well as the crude extracts from stem barks (16.5 ± 1.2 mm) and seeds (13.0 ± 1.4 mm). The profound inhibition of quorum sensing mediated processes in test pathogens by compounds 3, 4, 5 and 7 suggests the methylenedioxy- group that these compounds possess as the possible pharmacophore.}, } @article {pmid36811769, year = {2023}, author = {Machado, MAM and Castro, VS and da Cunha-Neto, A and Vallim, DC and Pereira, RCL and Dos Reis, JO and de Almeida, PV and Galvan, D and Conte-Junior, CA and Figueiredo, EES}, title = {Heat-resistant and biofilm-forming Escherichia coli in pasteurized milk from Brazil.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {2}, pages = {1035-1046}, pmid = {36811769}, issn = {1678-4405}, support = {444465/2020-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 313119/2020-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 310181/2021-6//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 200472/2022-4//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Animals ; *Escherichia coli/genetics ; *Milk/microbiology ; Hot Temperature ; Brazil ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Enterobacteriaceae ; }, abstract = {Escherichia coli harboring a transmissible locus of stress tolerance (tLST) and the ability to form biofilms represent a serious risk in dairy production. Thus, we aimed to evaluate the microbiological quality of pasteurized milk from two dairy producers in Mato Grosso, Brazil, with a focus on determining the possible presence of E. coli with heat resistance (60 °C/6 min), biofilm-forming potential phenotypes and genotypes, and antimicrobial susceptibility. For this, fifty pasteurized milk samples from producers named A and B were obtained for 5 weeks to investigate the presence of Enterobacteriaceae members, coliforms, and E. coli. For heat resistance, E. coli isolates were exposed to a water bath at 60 °C for 0 and 6 min. In antibiogram analysis, eight antibiotics belonging to six antimicrobial classes were analyzed. The potential to form biofilms was quantified at 570 nm, and curli expression by Congo Red was analyzed. To determine the genotypic profile, we performed PCR for the tLST and rpoS genes, and pulsed-field gel electrophoresis (PFGE) was used to investigate the clonal profile of the isolates. Thus, producer A presented unsatisfactory microbiological conditions regarding Enterobacteriaceae and coliforms for weeks 4 and 5, while all samples analyzed for producer B were contaminated at above-the-limit levels established by national and international legislation. These unsatisfactory conditions enabled us to isolate 31 E. coli from both producers (7 isolates from producer A and 24 isolates from producer B). In this way, 6 E. coli isolates (5 from producer A and 1 from producer B) were highly heat resistant. However, although only 6 E. coli showed a highly heat-resistant profile, 97% (30/31) of all E. coli were tLST-positive. In contrast, all isolates were sensitive to all antimicrobials tested. In addition, moderate or weak biofilm potential was verified in 51.6% (16/31), and the expression of curli and presence of rpoS was not always related to this biofilm potential. Therefore, the results emphasize the spreading of heat-resistant E. coli with tLST in both producers and indicate the biofilm as a possible source of contamination during milk pasteurization. However, the possibility of E. coli producing biofilm and surviving pasteurization temperatures cannot be ruled out, and this should be investigated.}, } @article {pmid36811767, year = {2023}, author = {Santos, PR and Kraus, RB and Ladeira, SL and Pereira, GM and Cunha, KF and Palhares, KE and Silva, ACA and Dors, GC and Lima, HG and Cereser, ND and Nascente, PS}, title = {Resistance profile and biofilm production of Enterococcus spp., Staphylococcus sp., and Streptococcus spp. from dairy farms in southern Brazil.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {2}, pages = {1217-1229}, pmid = {36811767}, issn = {1678-4405}, mesh = {Humans ; Animals ; Cattle ; Female ; Staphylococcus/genetics ; Enterococcus ; *Staphylococcal Infections/microbiology ; Chlorhexidine/pharmacology ; Brazil ; Farms ; Streptococcus ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Milk/microbiology ; *Mastitis, Bovine/microbiology ; }, abstract = {Milk is a high nutritional value food that helps in human development and growth. However, it can also harbor microorganisms. Therefore, the objective of this study was to isolate, identify and evaluate the resistance profile and pathogenicity factors of gram-positive cocci isolated from liners in milking rooms in the south of Rio Grande do Sul, Brazil. Biochemical and molecular tests were performed for the identification. The following were isolated: Enterococcus faecalis (10), Enterococcus faecium (4), Staphylococcus intermedius (1), Streptococcus uberis (1), and Streptococcus dysgalactiae (1). The susceptibility of isolated microorganisms to eight antibiotics was evaluated according to CLSI, and the genus that proved to be resistant to most of those was Enterococcus. In addition, all 17 isolates were able to form biofilm, which remained viable after the use of neutral, alkaline and alkaline-chlorinated detergent. The only product that was effective against biofilm of all microorganisms was chlorhexidine 2%. The results obtained highlight the importance of pre- and post-dipping tests on dairy properties, in which chlorhexidine is one of the disinfectants used. As observed, products indicated for cleaning and descaling pipes were not effective on biofilms of the different species tested.}, } @article {pmid36811095, year = {2023}, author = {Wang, Y and Lv, Q and Chen, Y and Xu, L and Feng, M and Xiong, Z and Li, J and Ren, J and Liu, J and Liu, B}, title = {Bilayer hydrogel dressing with lysozyme-enhanced photothermal therapy for biofilm eradication and accelerated chronic wound repair.}, journal = {Acta pharmaceutica Sinica. B}, volume = {13}, number = {1}, pages = {284-297}, pmid = {36811095}, issn = {2211-3835}, abstract = {Biofilms are closely associated with the tough healing and dysfunctional inflammation of chronic wounds. Photothermal therapy (PTT) emerged as a suitable alternative which could destroy the structure of biofilms with local physical heat. However, the efficacy of PTT is limited because the excessive hyperthermia could damage surrounding tissues. Besides, the difficult reserve and delivery of photothermal agents makes PTT hard to eradicate biofilms as expectation. Herein, we present a GelMA-EGF/Gelatin-MPDA-LZM bilayer hydrogel dressing to perform lysozyme-enhanced PTT for biofilms eradication and a further acceleration to the repair of chronic wounds. Gelatin was used as inner layer hydrogel to reserve lysozyme (LZM) loaded mesoporous polydopamine (MPDA) (MPDA-LZM) nanoparticles, which could rapidly liquefy while temperature rising so as to achieve a bulk release of nanoparticles. MPDA-LZM nanoparticles serve as photothermal agents with antibacterial capability, could deeply penetrate and destroy biofilms. In addition, the outer layer hydrogel consisted of gelatin methacryloyl (GelMA) and epidermal growth factor (EGF) promoted wound healing and tissue regeneration. It displayed remarkable efficacy on alleviating infection and accelerating wound healing in vivo. Overall, the innovative therapeutic strategy we came up with has significant effect on biofilms eradication and shows promising application in promoting the repair of clinical chronic wounds.}, } @article {pmid36810960, year = {2023}, author = {Mohanasundaram, P and Saral, AM}, title = {Phytochemical Screening, Antibacterial, Antifungal, Anti-Biofilm and Antioxidant Activity of Azadiracta Indica A. Juss. Flowers.}, journal = {Chemistry & biodiversity}, volume = {20}, number = {3}, pages = {e202201049}, doi = {10.1002/cbdv.202201049}, pmid = {36810960}, issn = {1612-1880}, support = {//VIT University/ ; }, mesh = {Humans ; *Antioxidants/chemistry ; Antifungal Agents/pharmacology/analysis ; Plant Extracts/chemistry ; Anti-Bacterial Agents/chemistry ; *Anti-Infective Agents/pharmacology ; Phytochemicals/chemistry ; Flowers/chemistry ; Biofilms ; }, abstract = {The present study involves investigation of Azadiracta Indica flowers with respect to its pharmacognostic properties, phytochemical screening, and its application as anti-oxidant, anti-biofilm, and anti-microbial agent. The Pharmacognostic characteristics were evaluated with respect to moisture content, total ash content, acid, and water-soluble ash content, swelling index, foaming index, and metal content. The macro and micronutrient content of the crude drug was estimated by AAS and Flame photometric methods and it gives the quantitative estimation of minerals, where calcium is present in abundance (88.64 mg/L). Soxhlet extraction was carried out in the increasing order of polarity of the solvent viz Petroleum Ether (PE), Acetone (AC), and Hydroalcohol (20 %) (HA) to extract the bioactive compounds. The characterization of the bioactive compounds of all the three extract have been carried out using gcms and lcms. The presence of 13 major compounds have been identified in PE extract and 8 compounds in AC extract using gcms studies. The HA extract is found to contain polyphenols, flavanoids, and glycosides. The antioxidant activity of the extracts was evaluated by DPPH, FRAP, and Phosphomolybdenum assay. This reveals that HA extract shows good scavenging activity than PE and AC extracts which is well correlated with the bioactive compounds, especially phenols which are present as a major component in the extract. The anti-microbial activity was investigated via Agar well diffusion method for all the extracts. Among all the extracts HA extract shows good antibacterial activity with MIC of 25 μg/mL and AC extract shows good anti-fungal activity with MIC of 25 μg/mL. The antibiofilm assay confirms that the HA extract shows good biofilm inhibition about 94 % among other extracts when tested on human pathogens. The results confirm that the HA extract of A. Indica flowers will be an excellent source of natural anti-oxidant and also antimicrobial agents. This paves the way for its potential uses in herbal product formulation.}, } @article {pmid36810950, year = {2023}, author = {Zhang, JJ and Feng, YM and Zhang, JR and Xiao, WL and Liu, SS and Zhou, X and Zhang, H and Wang, PY and Liu, LW and Yang, S}, title = {Resistance-driven innovations in the discovery of bactericides: novel triclosan derivatives decorating isopropanolamine moiety as promising anti-biofilm agents against destructive plant bacterial diseases.}, journal = {Pest management science}, volume = {79}, number = {7}, pages = {2443-2455}, doi = {10.1002/ps.7419}, pmid = {36810950}, issn = {1526-4998}, support = {//GZU (Guizhou University) Found for Newly Enrolled Talent (No. 202229)/ ; //National Natural Science Foundation of China (21877021, 32160661)/ ; //Program of Introducing Talents of Discipline to Universities of China (D20023, 111 Program)/ ; //the Guizhou Province [Qianjiaohe KY number (2020)004]/ ; //the Guizhou Provincial S&T Project (2018[4007])/ ; }, mesh = {*Triclosan/pharmacology ; Microbial Sensitivity Tests ; Oxadiazoles/chemistry ; *Xanthomonas ; Anti-Bacterial Agents/pharmacology/chemistry ; *Bacterial Infections ; Plant Diseases/prevention & control/microbiology ; *Oryza ; }, abstract = {BACKGROUND: Controlling bacterial infections in plants is a major challenge owing to the appearance of resistant strains. As a physical barrier, the bacterial biofilm helps bacterial infections acquire drug resistance by enabling bacteria to accommodate complex and volatile environmental conditions and avoid bactericidal effects. Thus, developing new antibacterial agents with antibiofilm potency is imperative.

RESULTS: A series of simple triclosan derivatives containing isopropanolamine moiety were elaborately designed and assessed for their antibacterial behavior. Bioassay results showed that some title compounds had excellent bioactivity against three destructive bacteria Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac) and Pseudomonas syringae pv. actinidiae (Psa). Notably, compound C8 displayed high bioactivities toward Xoo and Xac, with EC50 values were 0.34 and 2.11 μg mL[-1] , respectively. In vivo trials revealed that compound C8 exhibited excellent protective activities against rice bacterial blight and citrus bacterial canker at 200 μg mL[-1] , with control effectivenesses of 49.57% and 85.60%, respectively. Compound A4 had remarkably inhibitory activity toward Psa, with an EC50 value of 2.63 μg mL[-1] , and demonstrated outstanding protective activity with a value of 77.23% against Psa in vivo. Antibacterial mechanisms indicated that compound C8 dose-dependently prevented biofilm formation and extracellular polysaccharide production. C8 also significantly weakened the motility and pathogenicity of Xoo.

CONCLUSION: This study contributes to the development and excavation of novel bactericidal candidates with broad-spectrum antibacterial activity by targeting bacterial biofilm to control refractory plant bacterial diseases. © 2023 Society of Chemical Industry.}, } @article {pmid36810656, year = {2023}, author = {Zhang, J and Qi, H and Wang, M and Wei, Y and Liang, H}, title = {Enzymatically hydrolyzed sodium caseinate nanoparticles efficiently enhancing the solubility, stability, and antioxidant and anti-biofilm activities of hydrophobic Tanshinone IIA.}, journal = {Journal of materials chemistry. B}, volume = {11}, number = {11}, pages = {2440-2454}, doi = {10.1039/d2tb02263j}, pmid = {36810656}, issn = {2050-7518}, mesh = {*Caseins/chemistry ; Antioxidants/pharmacology ; Solubility ; *Nanoparticles/chemistry ; }, abstract = {Enzymatic hydrolysis has been validated as an appropriate strategy for improving the properties of natural protein. Here, we used enzymatic hydrolysis sodium caseinate (Eh NaCas) as a nano-carrier for enhancing the solubility, stability, and antioxidant and anti-biofilm activities of hydrophobic encapsulants. Tanshinone IIA (TA) was loaded into the hydrophobic regions of Eh NaCas by self-assembly, and the encapsulation efficiency could reach 96.54 ± 0.14% under an optimized host-guest ratio. After Eh NaCas packed, the TA-loaded Eh NaCas nanoparticles (Eh NaCas@TA) showed regular spheres, uniform particle size distribution and more optimal drug release. Moreover, the solubility of TA in aqueous solution increased over 2.4 × 10[5] times, and the TA guest molecules displayed excellent stability under light and other harsh environments. Interestingly, the vehicle protein and TA exhibited synergistic antioxidant effects. Furthermore, Eh NaCas@TA forcefully restrained the growth and destroyed the biofilm construction of Streptococcus mutans compared to free TA, showing positive antibacterial activity. The establishment of these results demonstrated the feasibility and functionality of edible protein hydrolysates as nano-carriers for loading natural plant hydrophobic extracts.}, } @article {pmid36810410, year = {2023}, author = {Messersmith, RE and Sage, FC and Johnson, JK and Langevin, SA and Forsyth, ER and Hart, MT and Hoffman, CM}, title = {Iron Sequestration by Galloyl-Silane Nano Coatings Inhibits Biofilm Formation of Sulfitobacter sp.}, journal = {Biomimetics (Basel, Switzerland)}, volume = {8}, number = {1}, pages = {}, pmid = {36810410}, issn = {2313-7673}, abstract = {Microbially-induced corrosion is the acceleration of corrosion induced by bacterial biofilms. The bacteria in the biofilms oxidize metals on the surface, especially evident with iron, to drive metabolic activity and reduce inorganic species such as nitrates and sulfates. Coatings that prevent the formation of these corrosion-inducing biofilms significantly increase the service life of submerged materials and significantly decrease maintenance costs. One species in particular, a member of the Roseobacter clade, Sulfitobacter sp., has demonstrated iron-dependent biofilm formation in marine environments. We have found that compounds that contain the galloyl moiety can prevent Sulfitobacter sp. biofilm formation by sequestering iron, thus making a surface unappealing for bacteria. Herein, we have fabricated surfaces with exposed galloyl groups to test the effectiveness of nutrient reduction in iron-rich media as a non-toxic method to reduce biofilm formation.}, } @article {pmid36809809, year = {2023}, author = {Aias, M and Azrad, M and Saad, G and Leshem, T and Hamo, Z and Rahmoun, LA and Peretz, A}, title = {Different bile acids have versatile effects on sporulation, toxin levels and biofilm formation of different Clostridioides difficile strains.}, journal = {Journal of microbiological methods}, volume = {206}, number = {}, pages = {106692}, doi = {10.1016/j.mimet.2023.106692}, pmid = {36809809}, issn = {1872-8359}, mesh = {Bile Acids and Salts/pharmacology ; *Clostridioides difficile ; Clostridioides ; *Bacterial Toxins ; Taurocholic Acid/pharmacology ; Biofilms ; Bacterial Proteins ; }, abstract = {Clostridioides difficile infection develops following ingestion of virulent stains by a susceptible host. Once germinated, toxins TcdA and TcdB, and in some of the strains binary toxin, are secreted, eliciting disease. Bile acids play a significant role in the process of spore germination and outgrowth, with cholate and its derivative enhancing colony formation, while chenodeoxycholate inhibit germination and outgrowth. This work investigated bile acids' impact on spore germination, toxin levels and biofilm formation in various strain types (STs). Thirty C. difficile isolates (A[+] B[+] CDT[-\+]) of different STs were exposed to increasing concentrations of the bile acids, cholic acid (CA), taurocholic acid (TCA) and chenodeoxycholic acid (CDCA). Following treatments, spore germination was determined. Toxin concentrations were semi-quantified using the C. Diff Tox A/B II™ kit. Biofilm formation was detected by the microplate assay with crystal violet. SYTO® 9 and propidium iodide staining were used for live and dead cell detection, respectively, inside the biofilm. Toxins levels were increased by 1.5-28-fold in response to CA and by 1.5-20-fold in response to TCA, and decreased by 1-37-fold due to CDCA exposure. CA had a concentration-dependent effect on biofilm formation, with the low concentration (0.1%) inducing- and the higher concentrations inhibiting biofilm formation, while CDCA significantly reduced biofilm production at all concentrations. There were no differences in the bile acids effects on different STs. Further investigation might identify a specific bile acids' combination with inhibitory effects on C. difficile toxin and biofilm production, which could modulate toxin formation to reduce the likelihood of developing CDI.}, } @article {pmid36809632, year = {2023}, author = {Xin, C and Wang, F and Zhang, J and Zhou, Q and Liu, F and Zhao, C and Song, Z}, title = {Secretions from Serratia marcescens Inhibit the Growth and Biofilm Formation of Candida spp. and Cryptococcus neoformans.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {61}, number = {2}, pages = {221-232}, pmid = {36809632}, issn = {1976-3794}, mesh = {Humans ; *Cryptococcus neoformans ; Antifungal Agents/pharmacology ; Candida ; Serratia marcescens ; Biofilms ; *Cryptococcosis/microbiology ; }, abstract = {Candida spp. and Cryptococcus are conditional pathogenic fungi that commonly infect immunocompromised patients. Over the past few decades, the increase in antifungal resistance has prompted the development of new antifungal agents. In this study, we explored the potential antifungal effects of secretions from Serratia marcescens on Candida spp. and Cryptococcus neoformans. We confirmed that the supernatant of S. marcescens inhibited fungal growth, suppressed hyphal and biofilm formation, and downregulated the expression of hyphae-specific genes and virulence-related genes in Candida spp. and C. neoformans. Furthermore, the S. marcescens supernatant retained biological stability after heat, pH, and protease K treatment. The chemical profile of the S. marcescens supernatant was characterized by ultra-high-performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry analysis and a total of 61 compounds with an mzCloud best match of greater than 70 were identified. In vivo, treatment with the S. marcescens supernatant reduced the mortality of fungi-infected Galleria mellonella. Taken together, our results revealed that the stable antifungal substances in the supernatant of S. marcescens have promising potential applications in the development of new antifungal agents.}, } @article {pmid36809069, year = {2023}, author = {de Souza, CM and Dos Santos, MM and Furlaneto-Maia, L and Furlaneto, MC}, title = {Adhesion and biofilm formation by the opportunistic pathogen Candida tropicalis: what do we know?.}, journal = {Canadian journal of microbiology}, volume = {69}, number = {6}, pages = {207-218}, doi = {10.1139/cjm-2022-0195}, pmid = {36809069}, issn = {1480-3275}, mesh = {*Candida tropicalis/genetics ; *Gene Regulatory Networks ; Biofilms ; Quorum Sensing ; Phenotype ; }, abstract = {Candida tropicalis is among the most important Candida species in terms of epidemiology, virulence and resistance. Considering the increase in C. tropicalis incidence and high rates of mortality associated with this species, knowledge of its adhesion and biofilm formation abilities is needed. These traits determine the persistence and survival of yeast on different indwelling medical devices and host sites. C. tropicalis is among the most adherent Candida species, and it has been described as a strong biofilm producer. Environmental factors, phenotypic switching and quorum sensing molecules can affect adhesion and biofilm growth. C. tropicalis can form sexual biofilms, which are promoted by mating pheromones. C. tropicalis biofilms are regulated by a wide and complex network of genes and signaling pathways that are currently poorly understood. Morphological studies showed improved biofilm architecture, which was related to the expression of several hypha-specific genes. Based on recent updates, research is still needed to increase our knowledge on the genetic network of adhesion and biofilm formation by C. tropicalis, as well as the protein diversity that mediates interactions with inert materials and biological surfaces. Here, we have reviewed the main aspects related to adhesion and biofilm formation in C. tropicalis and summarized current knowledge on the significance of these virulence factors in this opportunistic species.}, } @article {pmid36809043, year = {2023}, author = {Buzza, KM and Pluen, A and Doherty, C and Cheesapcharoen, T and Singh, G and Ledder, RG and Sreenivasan, PK and McBain, AJ}, title = {Modulation of Biofilm Formation and Permeability in Streptococcus mutans during Exposure To Zinc Acetate.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0252722}, pmid = {36809043}, issn = {2165-0497}, abstract = {The penetration of biofilms by antimicrobials is a potential limiting factor in biofilm control. This is relevant to oral health, as compounds that are used to control microbial growth and activities could also affect the permeability of dental plaque biofilm with secondary effects on biofilm tolerance. We investigated the effects of zinc salts on the permeability of Streptococcus mutans biofilms. Biofilms were grown with low concentrations of zinc acetate (ZA), and a transwell transportation assay was applied to test biofilm permeability in an apical-basolateral direction. Crystal violet assays and total viable counts were used to quantify the biofilm formation and viability, respectively, and short time frame diffusion rates within microcolonies were determined using spatial intensity distribution analysis (SpIDA). While the diffusion rates within biofilm microcolonies were not significantly altered, exposure to ZA significantly increased the overall permeability of S. mutans biofilms (P < 0.05) through decreased biofilm formation, particularly at concentrations above 0.3 mg/mL. Transport was significantly lower through biofilms grown in high sucrose conditions. IMPORTANCE Zinc salts are added to dentifrices to improve oral hygiene through the control of dental plaque. We describe a method for determining biofilm permeability and show a moderate inhibitory effect of zinc acetate on biofilm formation, and that this inhibitory effect is associated with increases in overall biofilm permeability.}, } @article {pmid36808649, year = {2023}, author = {Ghasemian, S and Karami-Zarandi, M and Heidari, H and Khoshnood, S and Kouhsari, E and Ghafourian, S and Maleki, A and Kazemian, H}, title = {Molecular characterizations of antibiotic resistance, biofilm formation, and virulence determinants of Pseudomonas aeruginosa isolated from burn wound infection.}, journal = {Journal of clinical laboratory analysis}, volume = {37}, number = {4}, pages = {e24850}, pmid = {36808649}, issn = {1098-2825}, mesh = {Humans ; Pseudomonas aeruginosa/genetics ; Virulence ; *Pseudomonas Infections/drug therapy/microbiology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Carbapenems/pharmacology ; beta-Lactamases/genetics ; *Burns/complications ; Microbial Sensitivity Tests ; Drug Resistance, Microbial ; Virulence Factors/genetics ; Biofilms ; *Wound Infection ; }, abstract = {BACKGROUND: Burn injuries result in disruption of the skin barrier against opportunistic infections. Pseudomonas aeruginosa is one of the main infectious agents colonizing burn wounds and making severe infections. Biofilm production and other virulence factors along with antibiotic resistance limit appropriate treatment options and time.

MATERIALS AND METHODS: Wound samples were collected from hospitalized burn patients. P. aeruginosa isolates and related virulence factors identified by the standard biochemical and molecular methods. Antibiotic resistance patterns were determined by the disc diffusion method and β-lactamase genes were detected by polymerase chain reaction (PCR) assay. To determine the genetic relatedness amongst the isolates, enterobacterial repetitive intergenic consensus (ERIC)-PCR was also performed.

RESULTS: Forty P. aeruginosa isolates were identified. All of these isolates were biofilm producers. Carbapenem resistance was detected in 40% of the isolates, and blaTEM (37/5%), blaVIM (30%), and blaCTX-M (20%) were the most common β-lactamase genes. The highest resistance was detected to cefotaxime, ceftazidime, meropenem, imipenem and piperacillin, and 16 (40%) isolates were resistant to these antibiotics. The minimum inhibitory concentrations (MIC) of colistin was lower than 2 μg/mL and no resistance was observed. Isolates were categorized to 17 MDR, 13 mono-drug resistance, and 10 susceptible isolates. High genetic diversity was also observed among the isolates (28 ERIC types) and most carbapenem-resistant isolates were classified into four main types.

CONCLUSION: Antibiotic resistance, particularly carbapenem resistance was considerable among the P. aeruginosa isolates colonizing burn wounds. Combining carbapenem resistance with biofilm production and virulence factors would result in severe and difficult-to-treat infections.}, } @article {pmid36807839, year = {2023}, author = {Hijazi, DM and Dahabiyeh, LA and Abdelrazig, S and Alqudah, DA and Al-Bakri, AG}, title = {Micafungin effect on Pseudomonas aeruginosa metabolome, virulence and biofilm: potential quorum sensing inhibitor.}, journal = {AMB Express}, volume = {13}, number = {1}, pages = {20}, pmid = {36807839}, issn = {2191-0855}, abstract = {The prevalence of antibiotic resistance in Pseudomonas aeruginosa places a heavy burden on the health care sectors urging the need to find alternative, non-antibiotic strategies. The interference with the P. aeruginosa quorum sensing (QS) system represents a promising alternative strategy to attenuate the bacterial virulency and its ability to form biofilms. Micafungin has been reported to impede the pseudomonal biofilm formation. However, the influences of micafungin on the biochemical composition and metabolites levels of P. aeruginosa have not been explored. In this study, the effect of micafungin (100 µg/mL) on the virulence factors, QS signal molecules and the metabolome of P. aeruginosa was studied using exofactor assay and mass spectrometry-based metabolomics approaches. Furthermore, confocal laser scanning microscopy (CLSM) using the fluorescent dyes ConA-FITC and SYPRO® Ruby was used to visualize micafungin disturbing effects on the pseudomonal glycocalyx and protein biofilm-constituents, respectively. Our findings showed that micafungin significantly decreased the production of various QS-controlled virulence factors (pyocyanin, pyoverdine, pyochelin and rhamnolipid), along with a dysregulation in the level of various metabolites involved in QS system, lysine degradation, tryptophan biosynthesis, TCA cycle, and biotin metabolism. In addition, the CLSM examination showed an altered matrix distribution. The presented findings highlight the promising role of micafungin as a potential quorum sensing inhibitor (QSI) and anti-biofilm agent to attenuate P. aeruginosa pathogenicity. In addition, they point to the promising role of metabolomics study in investigating the altered biochemical pathways in P. aeruginosa.}, } @article {pmid36807459, year = {2023}, author = {Lara, BR and de Camargo, BB and Paula, CR and Monari, GPM and Garces, HG and Arnoni, MV and Silveira, M and Gimenes, VMF and Leite Junior, DP and Bonfietti, LX and Oliveira, L and Melhem, MSC and Auler, M and Ramos, RTB and Dias, ALT and Silva, NC and Moreira, D and Richini-Pereira, VB and Anversa, L and Ruiz, LDS}, title = {Aspects related to biofilm production and antifungal susceptibility of clinically relevant yeasts of the genus Trichosporon.}, journal = {Medical mycology}, volume = {61}, number = {3}, pages = {}, doi = {10.1093/mmy/myad022}, pmid = {36807459}, issn = {1460-2709}, support = {2019/08419-7//Foundation for Research Support of the State of São Paulo/ ; }, mesh = {Humans ; Animals ; Antifungal Agents/pharmacology/therapeutic use ; Fluconazole/pharmacology ; *Trichosporon ; Caspofungin ; Itraconazole ; Amphotericin B/pharmacology ; *Trichosporonosis/microbiology/veterinary ; Biofilms ; Microbial Sensitivity Tests/veterinary ; }, abstract = {Trichosporonosis corresponds to a systemic fungal disease that leads to high mortality rates and is frequently associated with medical devices. It affects immunosuppressed patients in particular and is strongly linked to acquired human immunodeficiency, organ and tissue transplants, and malignant hematologic diseases such as leukemia and lymphomas. Trichosporon infections have been increasingly reported worldwide; however, little information is available either about their characteristics or the causative microorganism. Thus, the aims of the present study were: to investigate 59 yeasts of the genus Trichosporon by verifying the biofilm formation capacity of isolates; to analyze the susceptibility patterns of planktonic cells against the antifungals fluconazole, itraconazole, amphotericin-B, voriconazole, and caspofungin by comparing European Committee for Antimicrobial Susceptibility Testing (EUCAST) broth microdilution technique with the commercial method Etest; and to assess the susceptibility patterns of biofilm cells (sessile) against the same antifungals through broth microdilution. The ability to form biofilm on the surface of polystyrene plates was noted for all isolates, and 54.3% of samples were considered strong producers. Comparison between the antifungal susceptibility techniques evidenced that Etest showed higher and discordant minimum inhibitory concentrations (MICs) from those obtained by the microdilution method, especially for fluconazole, itraconazole, and caspofungin. Considering the susceptibility of biofilms, most species had high MIC50 and MIC90 against the tested antifungals, showing 4-to-66-fold higher concentrations for amphotericin B and 2-to-33-fold greater concentrations for caspofungin. These results highlight the importance of further studies with Trichosporon spp. for comparison between laboratory findings and in vivo response, considering both the susceptibility tests and the behavior of biofilm cells against drugs.}, } @article {pmid36807047, year = {2023}, author = {Delacuvellerie, A and Brusselman, A and Cyriaque, V and Benali, S and Moins, S and Raquez, JM and Gobert, S and Wattiez, R}, title = {Long-term immersion of compostable plastics in marine aquarium: Microbial biofilm evolution and polymer degradation.}, journal = {Marine pollution bulletin}, volume = {189}, number = {}, pages = {114711}, doi = {10.1016/j.marpolbul.2023.114711}, pmid = {36807047}, issn = {1879-3363}, mesh = {*Biodegradable Plastics ; Polymers ; Immersion ; Polyesters ; Plastics/metabolism ; Biofilms ; *Microbiota ; }, abstract = {The best-selling compostable plastics, polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT), can accidentally end up in the marine environment due to plastic waste mismanagement. Their degradation and colonization by microbial communities are poorly documented in marine conditions. To better understand their degradation, as well as the dynamics of bacterial colonization after a long immersion time (99, 160, and 260 days), PBAT, semicrystalline, and amorphous PLA films were immersed in a marine aquarium. Sequencing and chemical analyses were used in parallel to characterize these samples. Despite the variation in the chemical intrinsic parameters of these plastics, their degradation remains very slow. Microbial community structure varied according to the immersion time with a high proportion of Archaea. Moreover, the plastisphere structure of PBAT was specific. A better understanding of compostable plastic degradability is crucial to evaluate their impact on ecosystems and to eco-design new recyclable plastics with optimal degradation properties.}, } @article {pmid36807004, year = {2023}, author = {Toliopoulos, C and Giaouris, E}, title = {Marked inter-strain heterogeneity in the differential expression of some key stress response and virulence-related genes between planktonic and biofilm cells in Listeria monocytogenes.}, journal = {International journal of food microbiology}, volume = {390}, number = {}, pages = {110136}, doi = {10.1016/j.ijfoodmicro.2023.110136}, pmid = {36807004}, issn = {1879-3460}, mesh = {Humans ; *Bacterial Proteins/genetics/metabolism ; *Biofilms ; *Listeria monocytogenes/genetics/metabolism ; *Listeriosis/genetics/metabolism/microbiology ; Serogroup ; Virulence/genetics ; Stress, Physiological/physiology ; Adaptation, Biological/genetics/physiology ; Genetic Heterogeneity ; Gene Expression ; }, abstract = {Listeria monocytogenes is a facultatively intracellular pathogenic bacterium that can provoke invasive listeriosis, a severe foodborne infection in humans. Outside the host, this is capable to survive for long periods in soil, and water, as well as on plants, while, like many other microorganisms, this can also attach to abiotic surfaces, such as food contact ones, forming biofilms on them. It has been suggested that inside those sessile communities, L. monocytogenes cells not only display an increased stress tolerance but may also boost their pathogenicity. In this work, the expression of ten key stress response and/or virulence-related genes (i.e., groEL, hly, iap, inlA, inlB, lisK, mdrD, mdrL, prfA, and sigB) was studied in three different L. monocytogenes strains (AAL20066, AAL20107, and PL24), all isolated from foods and each belonging to a different listeriosis-associated serovar (1/2a, 1/2b, and 1/2c, respectively). For this, each strain was initially left to develop a mature biofilm on a model polystyrene surface (Petri dish) by incubating for 144 h (6 days) at 20 °C in tryptone soya broth (with medium renewal every 48 h). Following incubation, both biofilm and the surrounding free-swimming (planktonic) cells were recovered, and their gene expressions were comparatively evaluated through targeted reverse transcription-quantitative polymerase chain reactions (RT-qPCR). Results revealed a strain-dependent differential gene expression between the two cell types. Thus, for instance, in strain AAL20107 (ser. 1/2b) biofilm growth worryingly resulted in a significant overexpression of all the studied genes (P < 0.05), whereas in strain PL24 (ser. 1/2c), the expression of most genes (8/10) did not change upon biofilm growth, with only two of them (groEL and hly) being again significantly upregulated. Such transcriptomic strain variability in stress adaptation and/or virulence induction should be generally considered in the physiological studies of pathogenic biofilms and preferably upon designing and implementing novel and more efficient eradication methods.}, } @article {pmid36806829, year = {2023}, author = {Amorim, CF and Iglesias, BA and Pinheiro, TR and Lacerda, LE and Sokolonski, AR and Pedreira, BO and Moreira, KS and Burgo, TAL and Meyer, R and Azevedo, V and Portela, RW}, title = {Photodynamic inactivation of different Candida species and inhibition of biofilm formation induced by water-soluble porphyrins.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {42}, number = {}, pages = {103343}, doi = {10.1016/j.pdpdt.2023.103343}, pmid = {36806829}, issn = {1873-1597}, abstract = {BACKGROUND: Candida spp. is the main fungal genus related to infections in humans, and its treatment has become a challenge due to the production of biofilm and its resistance/multi-resistance profile to conventional antifungals. Antimicrobial photodynamic therapy stands out as a treatment characterized by a broad spectrum of antimicrobial action, being able to induce oxidative stress in pathogens, and porphyrins are photosensitizers with high selectivity to pathogens. Thus, this work aimed to analyze the photoinactivation of different species of Candida by two cationic (4-H2TMeP[+] and 3-H2TMeP[+]) and one anionic (4-H2TPSP[‒]) porphyrins.

MATERIALS AND METHODS: Microdilution assays were performed to determine the MIC100, with subsequent determination of MFC100. Determination of oxidative species was done through the use of scavengers, while biofilm morphological features were investigated using the atomic force microscopy.

RESULTS: Cationic porphyrins were significantly efficient in inactivating Candida albicans and non-albicans species with 100% growth inhibition and fungicidal activity (MFC100/MIC100 ≤ 4.0). The cationic porphyrins were also able to interfere in Candida spp biofilm formation. The photo-oxidative mechanism activated by 3-H2TMeP[+] in Candida spp. is concurrent with the production of singlet oxygen and oxygen radical species. In the AFM analysis, 3-H2TMeP[+] was able to reduce yeast adhesion to the surface.

CONCLUSIONS: Cationic porphyrins can photo-inactivate different species of Candida in both planktonic and biofilm-associated forms, and reduce the adhesion of these fungi to the surface.}, } @article {pmid36806045, year = {2023}, author = {Vetrivel, A and Vetrivel, P and Dhandapani, K and Natchimuthu, S and Ramasamy, M and Madheswaran, S and Murugesan, R}, title = {Inhibition of biofilm formation, quorum sensing and virulence factor production in Pseudomonas aeruginosa PAO1 by selected LasR inhibitors.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {36806045}, issn = {1618-1905}, abstract = {The quorum sensing network of Pseudomonas aeruginosa mediates the regulation of genes controlling biofilm formation and virulence factors. The rise of drug resistance to Pseudomonas aeruginosa infections has made quorum sensing-regulated biofilm formation in clinical settings a major issue. In the present study, LasR inhibitors identified in our previous study were evaluated for their antibiofilm and antiquorum sensing activities against P. aeruginosa PAO1. The compounds selected were (3-[2-(3,4-dimethoxyphenyl)-2-(1H-indol-3-yl)ethyl]-1-(2-fluorophenyl)urea) (C1), (3-(4-fluorophenyl)-2-[(3-methylquinoxalin-2-yl)methylsulfanyl]quinazolin-4-one) (C2) and (2-({4-[4-(2-methoxyphenyl)piperazin-1-yl]pyrimidin-2-yl} sulfanyl)-N-(2,4,6-trimethylphenyl)acetamide) (C3). The minimum inhibitory concentrations of C1 and C2 were 1000 μM, whereas that of C3 was 500 μM. At sub-MICs, the compounds showed potent antibiofilm activity without affecting the growth of P. aeruginosa PAO1. Electron microscopy confirmed the disruption of biofilm by the selected compounds. The antiquorum sensing activity of the compounds was revealed by the inhibition of violacein in Chromobacterium violaceum and the inhibition of swimming and swarming motilities in P. aeruginosa PAO1. Furthermore, the compounds also attenuated the production of quorum sensing-mediated virulence factors. The qRT-PCR revealed the downregulation of quorum sensing regulatory genes, namely lasI, lasR, rhlI, rhlR, lasB, pqsA and pqsR. The selected compounds also exhibited lower cytotoxicity against peripheral blood lymphocytes. Thus, this study could pave a way to explore these compounds for the development of therapeutic agent against Pseudomonas aeruginosa biofilm-related infections.}, } @article {pmid36805382, year = {2023}, author = {Jones, SU and Chew, CH and Yeo, CC and Abdullah, FH and Othman, N and Kee, BP and Chua, KH and Puah, SM}, title = {The phenotypes and genotypes associated with biofilm formation among methicillin-susceptible Staphylococcus aureus (MSSA) isolates collected from a tertiary hospital in Terengganu, Malaysia.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {36805382}, issn = {1618-1905}, support = {FRGS/1/2019/SKK08/UM/02/5//Fundamental Research Grant Scheme from the Malaysian Ministry of Higher Education/ ; FRGS/1/2019/SKK08/UM/02/5//Fundamental Research Grant Scheme from the Malaysian Ministry of Higher Education/ ; FRGS/1/2019/SKK08/UM/02/5//Fundamental Research Grant Scheme from the Malaysian Ministry of Higher Education/ ; FRGS/1/2019/SKK08/UM/02/5//Fundamental Research Grant Scheme from the Malaysian Ministry of Higher Education/ ; IF044-2020//Institut Mérieux-MSIDC Young Investigator Award Grant/ ; }, abstract = {Methicillin-susceptible Staphylococcus aureus (MSSA) is an important nosocomial pathogen worldwide. This study aims to investigate the in vitro biofilm-forming ability of clinical MSSA isolated from various sources in the main public tertiary referral hospital in Terengganu, Malaysia and to detect the presence of biofilm-associated and regulatory genes among these isolates. A total of 104 MSSA isolates [pus (n = 75), blood (n = 24), respiratory secretions (n = 2), eye (n = 2), and urine (n = 1)] were investigated for slime production and biofilm formation using Congo red agar and crystal violet microtitre plate, respectively. Fifteen MSSA isolates with varying degrees of biofilm formation were selected for validation via a real-time cell analyser. All isolates were screened for microbial surface components recognising adhesive matrix molecules (MSCRAMM) and accessory gene regulator (agr) using polymerase chain reaction assay. A total of 76.0% (79/104) isolates produced slime layer, while all isolates developed biofilm as follows: 52.8% (55/104) strong biofilm producers, 40.4% (42/104) intermediate biofilm producers, and 6.7% (7/104) weak biofilm producers. A total of 98.1% (102/104) isolates carried at least one of the screened MSCRAMM gene(s) with the eno gene detected at the highest rate (87.5%, 91/104), while the sasG gene was significantly associated with strong biofilm production (p = 0.015). Three agr groups, 1, 2, and 3, were detected among the MSSA isolates with a predominance of agr-3 (32.7%, 34/104). In conclusion, biofilm formation varied greatly among clinical MSSA isolates, and the presence of sasG gene and agr-1 may play important role in initiating MSSA infections via biofilm formation.}, } @article {pmid36801575, year = {2023}, author = {Cai, W and Cai, L and Zhao, J and Yao, H}, title = {Prokaryotic community interchange between distinct microhabitats causes community pressure on anammox biofilm development.}, journal = {Water research}, volume = {233}, number = {}, pages = {119726}, doi = {10.1016/j.watres.2023.119726}, pmid = {36801575}, issn = {1879-2448}, mesh = {*Anaerobic Ammonia Oxidation ; Bioreactors/microbiology ; Biofilms ; Bacteroidetes ; Proteobacteria ; Nitrogen ; Oxidation-Reduction ; *Ammonium Compounds ; Sewage/microbiology ; }, abstract = {Biofilms are an efficient way to underpin the biological process of wastewater treatment. However, little is known about the driving forces of biofilm formation and development in industrial settings. Long-term observation of anammox biofilms indicated the interplay between different microhabitats (biofilm, aggregate, plankton) was important in sustaining biofilm formation. SourceTracker analysis showed that 88.77 ± 2.26% of initial biofilm originated from the aggregate, however, independent evolution was led by anammox species in the later stage (182d and 245d). Noticeably, the source proportion of aggregate and plankton increased when temperature varied, suggesting an interchange of species between different microhabitats could be helpful to biofilm recovery. The microbial interaction pattern and community variation displayed similar trends, but the unknown source proportion of interaction was very high during the entire incubation (7-245d), thereby the same species may develop different relationships within the distinct microhabitats. The core phyla, Proteobacteria and Bacteroidota, accounted for ∼80% of interactions in all lifestyles, which is consistent with the fact that Bacteroidota played important role in the early stage of biofilm assembly. Although anammox species evolved few links with other OTUs, Candidatus Brocadiaceae still outcompeted the NS9 marine group to dominate the homogeneous selection process in the later stage (56-245d) of biofilm assembly, implying that the functional species may be decoupled from the core species in the microbial network. The conclusions will shed a light on the understanding of biofilm development in large-scale biosystems of wastewater treatment.}, } @article {pmid36800842, year = {2022}, author = {Hassan, PA and Hameed Saeed, C and Rashid, SA and Sorchee, SM and Shareef, SH}, title = {Identification of Streptococcus sanguinis genes producing biofilm from gingivitis.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {68}, number = {8}, pages = {34-40}, doi = {10.14715/cmb/2022.68.8.6}, pmid = {36800842}, issn = {1165-158X}, mesh = {Humans ; Streptococcus sanguis/genetics ; Biofilms ; *Microbiota ; *Gingivitis/genetics ; }, abstract = {Streptococcus sanguinis is a teeth commensal frontier colonizer and among the most common species in the oral biofilm. Dental plaque, caries, and gingivitis/periodontitis are caused by dysbiosis of oral flora. A biofilm assay was developed to investigate biofilm formation in S. sanguinis using the microtiter plate, tube, and Congo red agar methods in order to identify causing bacteria and determine responsible genes. Three genes, including pur B, thr B, and pyre E, were suspected of playing a role in forming in vivo biofilms in S. sanguinis. The present study shows these genes to be responsible for increased biofilm formation in gingivitis patients.}, } @article {pmid36800793, year = {2023}, author = {Seredin, PV and Ippolitov, YA and Goloshchapov, DL and Kashkarov, VM and Ippolitov, IY and Solaiman, MA}, title = {[Distinctions in molecular composition of the dental biofilm depending on the method of exo-/endogeneous caries prevention and cariogenic condition of a patient].}, journal = {Stomatologiia}, volume = {102}, number = {1}, pages = {86-93}, doi = {10.17116/stomat202310201186}, pmid = {36800793}, issn = {0039-1735}, mesh = {Humans ; *Dental Caries Susceptibility ; Australia ; *Dental Caries/prevention & control ; Biofilms ; Phosphates ; Lipids ; }, abstract = {PURPOSE OF THE STUDY: For the first time distinctions of molecular composition of the dental biofilm at the stages of exo- and endogeneous caries prevention were studied for persons with different cariogenic conditions involving synchrotron molecular spectroscopy techniques.

MATERIAL AND METHODS: The samples of the dental biofilm collected from participants of the research were studied at the different stages of experiment. The studies of molecular composition of the biofilms were employed involving the equipment set in the Infrared Microspectroscopy (IRM) laboratory of Australian synchrotron.

RESULTS: Basing on the data obtained by synchrotron infrared spectroscopy with Fourier transform as well as using the calculations of the ratios between organic and mineral components and also statistical analysis of the data we could estimate the changes proceeding in the molecular composition of dental biofilm in a dependence of homeostasis conditions in the oral cavity at the stages of exo- and endogeneous caries prevention.

CONCLUSION: Observed changes in the values of phosphate/protein/lipid, phosphate/mineral and phospholipid/lipid ratios as well as the presence of statistically significant intra- and intergroup in these coefficients mean that mechanisms of adsorption for the ions, compounds and molecular complexes incoming from the oral fluid into the dental biofilm at the stage of exo-/endogeneous caries prevention are different for the patients in normal condition and for those ones with the developing caries.}, } @article {pmid36799228, year = {2023}, author = {Hagstrand Aldman, M and Thompson, O and Påhlman, LI}, title = {Biofilm formation is associated with poor outcome in prosthetic joint infections caused by Staphylococcus lugdunensis.}, journal = {Infectious diseases (London, England)}, volume = {55}, number = {5}, pages = {328-332}, doi = {10.1080/23744235.2023.2180534}, pmid = {36799228}, issn = {2374-4243}, mesh = {Humans ; *Staphylococcus lugdunensis ; *Staphylococcal Infections/drug therapy/microbiology ; Anti-Bacterial Agents/therapeutic use ; Biofilms ; Rifampin/therapeutic use ; *Arthritis, Infectious/drug therapy ; *Prosthesis-Related Infections/drug therapy/microbiology ; }, abstract = {BACKGROUND: Staphylococcus lugdunensis has been described as a pathogen of increasing importance in prosthetic joint infections (PJI). Our aim was to describe the clinical presentation of PJI caused by S. lugdunensis, and to correlate the biofilm-forming ability of the bacterial isolates to clinical outcome.

METHOD: S. lugdunensis isolates from PJI episodes during 2015-2019 were included and analysed for biofilm formation using a microtiter plate assay. Medical records from the corresponding patients were reviewed.

RESULTS: We identified 36 patients with PJI caused by S. lugdunensis during the study period. Early postoperative PJIs were most frequent (n = 20, 56%). Surgical intervention was performed in a majority of the patients (n = 33, 92%), and the dominating type of antibiotic treatment was a combination of rifampicin and ciprofloxacin (n = 27, 75%). The treatment success-rate was 81% (n = 29). All isolates causing PJI were able to form biofilm in vitro. Biofilm formation was significantly stronger in isolates causing relapsing vs non-relapsing PJI (mean OD550 3.1 ± 0.23 vs 1.14 ± 0.73 p = .001) and strong biofilm formation was also associated with late acute hematogenic PJI (mean OD550 1.8 ± 0.93 vs. 0.93 ± 0.81, p = .01).

CONCLUSION: Strong biofilm production in S. lugdunensis isolates was associated with relapse in PJI.}, } @article {pmid36798165, year = {2023}, author = {Razgaleh, SA and Wrench, A and Jones, AD}, title = {Surface Energy and Viscoelastic Characteristics of Staphylococcus epidermidis and Cutibacterium acnes Biofilm on Commercial Skin Constructs versus Agar.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36798165}, abstract = {Biofilms are recalcitrant to both study and infectious disease treatment as it requires not only the study or management of single organism behavior, but also many dynamical interactions including but not limited to bacteria-bacteria, bacteria-host, bacteria-nutrients, and bacteria-material across multiple time scales. This study performs comparative and quantitative research of two materials used in biofilm research, TSA agar and skin epidermal, to reveal how adhesion effects viscoelastic properties of biofilms at long time scales. We show that the host surface stressors, such as wettability and surface energy, impact the biofilm's mechanical integrity and viscoelastic properties. While it is known that the bacteria-material interface influences initial biofilm formation and external stress influences mature biofilm function, this study examines the influence of the bacteria-material interface on mature biofilms. These mechanical viscoelastic properties have the potential to determine metabolite and pathogenesis pathways which means that the platform researchers use to study impacts the outcome.}, } @article {pmid36797306, year = {2023}, author = {Lai, SJ and Tu, IF and Tseng, TS and Tsai, YH and Wu, SH}, title = {The deficiency of poly-β-1,6-N-acetyl-glucosamine deacetylase trigger A. baumannii to convert to biofilm-independent colistin-tolerant cells.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {2800}, pmid = {36797306}, issn = {2045-2322}, mesh = {*Colistin/pharmacology/metabolism ; Glucosamine/metabolism ; Anti-Bacterial Agents/pharmacology/metabolism ; Biofilms ; *Acinetobacter baumannii ; Microbial Sensitivity Tests ; Drug Resistance, Multiple, Bacterial ; }, abstract = {Acinetobacter baumannii is a nosocomial pathogen that can be resistant to antibiotics by rapidly modulating its anti-drug mechanisms. The multidrug-resistant A. baumannii has been considered one of the most threatening pathogens to our society. Biofilm formation and persistent cells within the biofilm matrix are recognized as intractable problems, especially in hospital-acquired infections. Poly-β-1,6-N-acetyl-glucosamine (PNAG) is one of the important building blocks in A. baumannii's biofilm. Here, we discover a protein phosphoryl-regulation on PNAG deacetylase, AbPgaB1, in which residue Ser411 was phosphorylated. The phosphoryl-regulation on AbPgaB1 modulates the product turnover rate in which deacetylated PNAG is produced and reflected in biofilm production. We further uncovered the PgaB deficient A. baumannii strain shows the lowest level of biofilm production but has a high minimal inhibition concentration to antibiotic colistin and tetracycline. Based on bactericidal post-antibiotic effects and time-dependent killing assays with antibacterial drugs, we claim that the PgaB-deficient A. baumannii converts to colistin-tolerant cells. This study utilizes a biofilm-independent colistin-tolerant model of A. baumannii to further investigate its characteristics and mechanisms to better understand clinical outcomes.}, } @article {pmid36796467, year = {2023}, author = {You, J and Park, J and Choi, D and Yun, J and Choi, H and Lee, IH}, title = {Implant-associated biofilm infection established in an experimental Galleria mellonella model.}, journal = {Developmental and comparative immunology}, volume = {142}, number = {}, pages = {104670}, doi = {10.1016/j.dci.2023.104670}, pmid = {36796467}, issn = {1879-0089}, mesh = {Animals ; *Methicillin-Resistant Staphylococcus aureus/physiology ; *Moths/microbiology ; Larva/microbiology ; Bacteria ; Biofilms ; Anti-Bacterial Agents ; *Staphylococcal Infections ; Microbial Sensitivity Tests ; }, abstract = {The study reports in vivo biofilm infection implemented in an insect model. We mimicked implant-associated biofilm infections in Galleria mellonella larvae using toothbrush bristles and methicillin-resistant Staphylococcus aureus (MRSA). In vivo biofilm formation on bristle was achieved by sequentially injecting a bristle and MRSA into the larval hemocoel. It was found that biofilm formation was in progress without any external sign of infection in most of the bristle-bearing larvae for 12 h after MRSA inoculation. Whereas the activation of the prophenoloxidase system did not affect the preformed in vitro MRSA biofilms, an antimicrobial peptide interfered with in vivo biofilm formation when injected into bristle-bearing larvae infected with MRSA. Finally, our confocal laser scanning microscopic analysis revealed that the biomass of the in vivo biofilm is greater compared to that of the in vitro biofilm and harbors a distribution of dead cells, which might be bacteria and/or host cells.}, } @article {pmid36793505, year = {2023}, author = {Fowler, SJ and Torresi, E and Dechesne, A and Smets, BF}, title = {Biofilm thickness controls the relative importance of stochastic and deterministic processes in microbial community assembly in moving bed biofilm reactors.}, journal = {Interface focus}, volume = {13}, number = {2}, pages = {20220069}, pmid = {36793505}, issn = {2042-8898}, abstract = {Deterministic and stochastic processes are believed to play a combined role in microbial community assembly, though little is known about the factors determining their relative importance. We investigated the effect of biofilm thickness on community assembly in nitrifying moving bed biofilm reactors using biofilm carriers where maximum biofilm thickness is controlled. We examined the contribution of stochastic and deterministic processes to biofilm assembly in a steady state system using neutral community modelling and community diversity analysis with a null-modelling approach. Our results indicate that the formation of biofilms results in habitat filtration, causing selection for phylogenetically closely related community members, resulting in a substantial enrichment of Nitrospira spp. in the biofilm communities. Stochastic assembly processes were more prevalent in biofilms of 200 µm and thicker, while stronger selection in thinner (50 µm) biofilms could be driven by hydrodynamic and shear forces at the biofilm surface. Thicker biofilms exhibited greater phylogenetic beta-diversity, which may be driven by a variable selection regime caused by variation in environmental conditions between replicate carrier communities, or by drift combined with low migration rates resulting in stochastic historical contingency during community establishment. Our results indicate that assembly processes vary with biofilm thickness, contributing to our understanding of biofilm ecology and potentially paving the way towards strategies for microbial community management in biofilm systems.}, } @article {pmid36792064, year = {2023}, author = {Kao, S and Serfecz, J and Sudhakar, A and Likosky, K and Romiyo, V and Tursi, S and Tükel, Ç and Wilson, JW}, title = {Salmonella enterica serovar Typhimurium STM1266 encodes a regulator of curli biofilm formation: the brfS gene.}, journal = {FEMS microbiology letters}, volume = {370}, number = {}, pages = {}, doi = {10.1093/femsle/fnad012}, pmid = {36792064}, issn = {1574-6968}, mesh = {Animals ; Mice ; *Bacterial Proteins/metabolism ; Salmonella typhimurium ; Serogroup ; *Escherichia coli Proteins/genetics ; Biofilms ; Escherichia coli/genetics/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {The major biofilm pathway in Salmonella enterica serovar Typhimurium involves specific growth conditions that induce the csgA gene whose product forms surface curli fibers that mediate biofilm formation. We have found that the previously uncharacterized STM1266 gene in S. Typhimurium plays a role in regulating biofilm formation via the curli pathway. S. Typhimurium ΔSTM1266 strains display a biofilm defect, and overexpression of STM1266 results in enhanced biofilm formation. STM1266 deletion resulted in lowered csgA expression using promoter-reporter β-galactosidase assays, and csgA and csgD deletions abrogate the effects of STM1266 overexpression on biofilm formation while deletion of bcsA (encoding an essential enzyme for cellulose formation) has no effect. In a mouse infection model, the ΔSTM1266 strain displayed results similar to those seen for previously reported ΔcsgA strains. The STM1266 gene is predicted to encode a DNA-binding transcriptional regulator of the MerR family and is homologous to the Escherichia coli BluR regulator protein. We respectfully propose to ascribe the name brfS (biofilm regulator for Salmonella Typhimurium) to the STM1266 gene.}, } @article {pmid36791856, year = {2023}, author = {Chen, S and Haga, M and Imai, I and Sakai, R and Fujita, MJ}, title = {Function of the algicidal bacterium Pseudomonas sp. Go58 isolated from the biofilm on a water plant, and its active compounds, pyoluteorins.}, journal = {The Science of the total environment}, volume = {872}, number = {}, pages = {162088}, doi = {10.1016/j.scitotenv.2023.162088}, pmid = {36791856}, issn = {1879-1026}, mesh = {Biofilms ; *Cyanobacteria ; *Microcystis ; Pseudomonas ; Water ; }, abstract = {In the development of applications to mitigate nuisance cyanobacterial blooms, environmentally friendly approaches have gained much attention. Recently, we found a bacterial strain Go58, which was isolated from the biofilm of a water plant, that showed potent algicidal activity against the bloom-forming cyanobacterium Microcystis aeruginosa. Whole genome sequencing of strain Go58 suggested that it is potentially a novel species closely related to Pseudomonas protegens. Pyoluteorins were obtained from the culture broth of this strain, and they demonstrated high toxicity against cultured cyanobacterial species, including M. aeruginosa and Anabaena cylindrica, but less toxicity against eukaryotic microalgae and other aquatic organisms. The production of pyoluteorin was enhanced by the presence of the target cyanobacterium. When a wild-caught microalgal consortium was treated with either strain Go58 or pyoluteorin, both efficiently suppressed the growth of harmful wild cyanobacteria, but promoted the growth of some specific eukaryotic microalgae. Since P. protegens is globally ubiquitous and highly anticipated to be a biopesticide for infectious diseases in the field of agriculture, the similar bacterial group identified in this study may also have potential as a safe on-site collectable biological countermeasure for controlling cyanobacterial blooms.}, } @article {pmid36791517, year = {2023}, author = {Zarei, M and Rahimi, S and Fazlara, A and Anvari, SE}, title = {High biofilm-forming Pseudomonas strains isolated from poultry slaughterhouse surfaces: Their importance in the persistence of Salmonella enteritidis in slaughterhouses.}, journal = {International journal of food microbiology}, volume = {390}, number = {}, pages = {110126}, doi = {10.1016/j.ijfoodmicro.2023.110126}, pmid = {36791517}, issn = {1879-3460}, mesh = {Animals ; *Salmonella enteritidis ; *Poultry/microbiology ; Pseudomonas ; Abattoirs ; Biofilms ; }, abstract = {The surfaces of poultry slaughterhouse equipment are significant sources of contamination with Pseudomonas strains, which leads to spoilage of poultry meat during subsequent refrigerated storage. In this study, Pseudomonas strains with high biofilm-forming ability were isolated from different surfaces of the poultry slaughterhouse equipment, identified based on molecular data, and characterized their biofilm-forming ability. After 24 h of incubation at 25 °C, 54 out of 58 Pseudomonas strains produced biofilm in vitro on polystyrene microplates. Seven isolates with high-ability to produce biofilm were identified as P. fragi (three strains), P. fluorescens (two strains), P. lundensis and P. cedrina. Despite their differences, these strains produced high amounts of biofilm in pure- and dual-species cultures with S. enteritidis on stainless steel surfaces. However, their ability to produce dual-species biofilms with S. enteritidis depends on whether S. enteritidis form the biofilm simultaneously with the Pseudomonas strains or whether Pseudomonas strains have already formed a biofilm. In concurrent inoculation, S. enteritidis participated in biofilm formation with all seven Pseudomonas strains with varying percent contributions. However, in delayed inoculation, S. enteritidis did not contribute in the biofilm formed by P. lundensis R26, P. fragi R39, and P. fluorescens R47. In addition to highlighting the complexity of bacterial interactions associated with Pseudomonas strains, these results showed that Pseudomonas strains can be implicated in Salmonella persistence in poultry slaughterhouses.}, } @article {pmid36787160, year = {2023}, author = {Peerzada, Z and Shah, MD and Kharkar, PS and Desai, KB}, title = {Exploration of the inhibitory effect of Cassia fistula on quorum sensing mediated virulence factor production and biofilm activity in Pseudomonas aeruginosa: an in vivo study in model organism Caenorhabditis elegans.}, journal = {Journal of medical microbiology}, volume = {72}, number = {2}, pages = {}, doi = {10.1099/jmm.0.001578}, pmid = {36787160}, issn = {1473-5644}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Caenorhabditis elegans/microbiology ; *Cassia ; Pseudomonas aeruginosa/genetics ; *Virulence Factors/genetics ; Plant Extracts/pharmacology ; }, abstract = {Introduction. Resistance to antibiotics is leading to challenges in the treatment of microbial diseases. One amongst the various approaches to control these pathogens is quorum sensing (QS), which is used to rectify resistance issues. Blocking the bacterial QS circuit is the most reliable anti-virulence therapy to control pathogenicity-associated genes. Pseudomonas aeruginosa is a contagious bacterium that proliferates in the host by using signalling molecules like acyl-homoserine lactones; these molecules generate and disseminate toxins and virulence factors for increasing host infection.Hypothesis. The herb Cassia fistula is known to have antimicrobial, antidiabetic, anti-inflammatory, antitumor medicinal properties amongst others. We hypothesize that its crude extracts will inhibit the QS circuit of Pseudomonas aeruginosa (P. aeruginosa).Aim. The research work was aimed at evaluating anti-quorum sensing and anti-biofilm activity of various crude extracts from Cassia fistula against P. aeruginosa.Methodology. Various extraction methods and solvents were availed for maximum separation, and the extracts were screened for anti-quorum sensing activity. The most potent Fruit Ethyl acetate (FEE) extract at non-inhibitory concentrations was found to interrupt both short-chain (RhlI/R) and long-chain (LasI/R) QS circuits and other virulence factors (P<0.05) such as elastase, protease, rhamnolipids and pyocyanin levels in P. aeruginosa. Biofilm inhibitory properties of FEE were demonstrated using atomic force microscopy, scanning electron microscope and confocal laser microscope. Caenorhabditis elegans infection model (Paralytic assay) was developed to determine the protective role of FEE by reducing the pathogenicity of P. aeruginosa.Results. The study results suggest that hot crude FEE extract interfered in the QS circuit, leading to comprehensive debilitation of QS-controlled virulence factors. The extract reduced virulence factor production in P. aeruginosa at 4 mg ml[-1] concentration whilst paradoxically promoting biofilm formation. Possibly, higher sugar content in the extract promoted clump formation of biofilm architecture by increasing exopolysaccharide production. Moreover, in vivo analysis of bacterial pathogenesis on Caenorhabditis elegans reveals a drastic increase in survival rates in FEE treated worms compared to untreated control.Conclusions. FEE showed promising QS inhibitory activity against P. aeruginosa. In the future, additional purification of crude FEE is required to remove carbohydrates, and pure isolated phytochemicals from FEE could be used as therapeutic agents to control QS-mediated infections in P. aeruginosa.}, } @article {pmid36786593, year = {2023}, author = {Chen, Z and Zarazúa-Osorio, B and Srivastava, P and Fujita, M and Igoshin, OA}, title = {The Slowdown of Growth Rate Controls the Single-Cell Distribution of Biofilm Matrix Production via an SinI-SinR-SlrR Network.}, journal = {mSystems}, volume = {8}, number = {2}, pages = {e0062222}, pmid = {36786593}, issn = {2379-5077}, mesh = {*Extracellular Polymeric Substance Matrix/metabolism ; *Bacterial Proteins/genetics ; Gene Expression Regulation, Bacterial ; Biofilms ; Bacillus subtilis/genetics ; }, abstract = {In Bacillus subtilis, master regulator Spo0A controls several cell-differentiation pathways. Under moderate starvation, phosphorylated Spo0A (Spo0A~P) induces biofilm formation by indirectly activating genes controlling matrix production in a subpopulation of cells via an SinI-SinR-SlrR network. Under severe starvation, Spo0A~P induces sporulation by directly and indirectly regulating sporulation gene expression. However, what determines the heterogeneity of individual cell fates is not fully understood. In particular, it is still unclear why, despite being controlled by a single master regulator, biofilm matrix production and sporulation seem mutually exclusive on a single-cell level. In this work, with mathematical modeling, we showed that the fluctuations in the growth rate and the intrinsic noise amplified by the bistability in the SinI-SinR-SlrR network could explain the single-cell distribution of matrix production. Moreover, we predicted an incoherent feed-forward loop; the decrease in the cellular growth rate first activates matrix production by increasing in Spo0A phosphorylation level but then represses it via changing the relative concentrations of SinR and SlrR. Experimental data provide evidence to support model predictions. In particular, we demonstrate how the degree to which matrix production and sporulation appear mutually exclusive is affected by genetic perturbations. IMPORTANCE The mechanisms of cell-fate decisions are fundamental to our understanding of multicellular organisms and bacterial communities. However, even for the best-studied model systems we still lack a complete picture of how phenotypic heterogeneity of genetically identical cells is controlled. Here, using B. subtilis as a model system, we employ a combination of mathematical modeling and experiments to explain the population-level dynamics and single-cell level heterogeneity of matrix gene expression. The results demonstrate how the two cell fates, biofilm matrix production and sporulation, can appear mutually exclusive without explicitly inhibiting one another. Such a mechanism could be used in a wide range of other biological systems.}, } @article {pmid36786569, year = {2023}, author = {Cont, A and Vermeil, J and Persat, A}, title = {Material Substrate Physical Properties Control Pseudomonas aeruginosa Biofilm Architecture.}, journal = {mBio}, volume = {14}, number = {2}, pages = {e0351822}, pmid = {36786569}, issn = {2150-7511}, mesh = {Humans ; *Pseudomonas aeruginosa/genetics ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Pseudomonas Infections/microbiology ; }, abstract = {In the wild, bacteria are most frequently found in the form of multicellular structures called biofilms. Biofilms grow at the surface of abiotic and living materials with wide-ranging mechanical properties. The opportunistic pathogen Pseudomonas aeruginosa forms biofilms on indwelling medical devices and on soft tissues, including burn wounds and the airway mucosa. Despite the critical role of substrates in the foundation of biofilms, we still lack a clear understanding of how material mechanics regulate their architecture and the physiology of resident bacteria. Here, we demonstrate that physical properties of hydrogel material substrates define P. aeruginosa biofilm architecture. We show that hydrogel mesh size regulates twitching motility, a surface exploration mechanism priming biofilms, ultimately controlling the organization of single cells in the multicellular community. The resulting architectural transitions increase P. aeruginosa's tolerance to colistin, a last-resort antibiotic. In addition, mechanical regulation of twitching motility affects P. aeruginosa clonal lineages, so that biofilms are more mixed on relatively denser materials. Our results thereby establish material properties as a factor that dramatically affects biofilm architecture, antibiotic efficacy, and evolution of the resident population. IMPORTANCE The biofilm lifestyle is the most widespread survival strategy in the bacterial world. Pseudomonas aeruginosa biofilms cause chronic infections and are highly recalcitrant to antimicrobials. The genetic requirements allowing P. aeruginosa to grow into biofilms are known, but not the physical stimuli that regulate their formation. Despite colonizing biological tissues, investigations of biofilms on soft materials are limited. In this work, we show that biofilms take unexpected forms when growing on soft substrates. The physical properties of the material shape P. aeruginosa biofilms by regulating surface-specific twitching motility. Physical control of biofilm morphogenesis ultimately influences the resilience of biofilms to antimicrobials, linking physical environment with tolerance to treatment. Altogether, our work established that the physical properties of a surface are a critical environmental regulator of biofilm biogenesis and evolution.}, } @article {pmid36781489, year = {2023}, author = {Çam, S and Bicek, S}, title = {The effects of temperature, salt, and phosphate on biofilm and exopolysaccharide production by Azotobacter spp.}, journal = {Archives of microbiology}, volume = {205}, number = {3}, pages = {87}, pmid = {36781489}, issn = {1432-072X}, support = {19272//Harran University (HÜBAP)/ ; 19272//Harran University (HÜBAP)/ ; }, mesh = {*Azotobacter ; Sodium Chloride/pharmacology ; Temperature ; Phosphates ; Biofilms ; Polysaccharides, Bacterial ; }, abstract = {Inoculation of agriculturally important biofilms to plants under stress conditions has been of great interest in recent years. Therefore, in this study, biofilm- and exopolysaccharide (EPS)-forming ability of Azotobacter spp. was examined under different temperatures, NaCl concentrations, and phosphate levels. Azotobacter strains formed varying levels of biofilm and EPS depending on the tested factors. The pattern of biofilm formation was similar to that of EPS production under the conditions tested. Biofilm and EPS production at 28 °C was consistently higher than at either 18 or 37 °C. Biofilm production significantly increased in A. chroococcum strains (SBS2, SBS4, and SBS12) and A. vinelandii SBS6 with increasing salinity. Furthermore, a strong negative correlation was observed between biofilm or EPS production and increasing phosphate concentrations. Higher phosphate concentrations decreased biofilm and EPS production. In conclusion, contrary to temperature and phosphate effect, salinity differently affected biofilm and EPS production by Azotobacter strains.}, } @article {pmid36780700, year = {2023}, author = {Sharma, K and Pandey, S and Sekar, H and Alan, T and Gundabala, V}, title = {Microfluidics Based Generation of Curcumin Loaded Microfibrous Mat against Staphylococcus aureus Biofilm by Photodynamic Therapy.}, journal = {ACS applied bio materials}, volume = {6}, number = {3}, pages = {1092-1104}, doi = {10.1021/acsabm.2c00971}, pmid = {36780700}, issn = {2576-6422}, mesh = {Humans ; Staphylococcus aureus ; *Methicillin-Resistant Staphylococcus aureus ; Photosensitizing Agents/pharmacology/therapeutic use ; *Curcumin/pharmacology ; Microfluidics ; *Photochemotherapy/methods ; Biofilms ; *Staphylococcal Infections/drug therapy ; }, abstract = {The rapid increase in multidrug resistant biofilm infections is a major concern for global health. A highly effective therapy is required for the treatment of biofilm related infections. In this study, curcumin loaded alginate microfibers were generated by using the microfluidic technique. In this strategy, alginate microfibers are used as a carrier for the encapsulation of curcumin and then are irradiated with blue light to assess the efficacy of a combined therapy (blue light + curcumin) against drug resistant Staphylococcus aureus (S. aureus). The advantage of utilizing photodynamic therapy (PDT) is the usage of a non-antibiotic mode to inactivate bacterial cells. In the presence of blue light, the curcumin loaded alginate microfibers have shown good eradication activity against biofilms formed by multidrug resistant S. aureus. We achieved different diameters of curcumin loaded alginate microfibers through manipulation of flow rates. The curcumin loaded microfibers were characterized for their size, morphology, and curcumin encapsulation. Further, the efficacy of these microfibers in the presence of blue light has been evaluated against biofilm forming S. aureus (NCIM 5718) through optical and electron microscopy. This study employs microfluidic techniques to obtain an efficacious and cost-effective microfibrous scaffold for controlled release of curcumin to treat biofilms in the presence of blue light.}, } @article {pmid36779942, year = {2023}, author = {Song, L and Yang, H and Meng, X and Su, R and Cheng, S and Wang, H and Bai, X and Guo, D and Lü, X and Xia, X and Shi, C}, title = {Inhibitory Effects of Trans-Cinnamaldehyde Against Pseudomonas aeruginosa Biofilm Formation.}, journal = {Foodborne pathogens and disease}, volume = {20}, number = {2}, pages = {47-58}, doi = {10.1089/fpd.2022.0073}, pmid = {36779942}, issn = {1556-7125}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Pseudomonas aeruginosa ; Extracellular Polymeric Substance Matrix ; Biofilms ; Quorum Sensing/genetics ; }, abstract = {Pseudomonas aeruginosa biofilm formation has been considered to be an important determinant of its pathogenicity in most infections. The antibiofilm activity of trans-cinnamaldehyde (TC) against P. aeruginosa was investigated in this study. Results demonstrated that the minimum inhibitory concentration (MIC) of TC against P. aeruginosa was 0.8 mg/mL, and subinhibitory concentrations (SICs) was 0.2 mg/mL and below. Crystal violet staining showed that TC at 0.05-0.2 mg/mL reduced biofilm biomass in 48 h in a concentration-dependent mode. The formation area of TC-treated biofilms was significantly declined (p < 0.01) on the glass slides observed by light microscopy. Field-emission scanning electron microscopy further demonstrated that TC destroyed the biofilm morphology and structure. Confocal laser scanning microscopic observed the dispersion of biofilms and the reduction of exopolysaccharides after TC treatment stained with concanavalin A (Con-A)-fluorescein isothiocyanate conjugate and Hoechst 33258. Meanwhile, TC caused a significant decrease (p < 0.01) in the component of polysaccharides, proteins, and DNA in extracellular polymeric substance. The swimming and swarming motility and quorum sensing of P. aeruginosa was also found to be significantly inhibited (p < 0.01) by TC at SICs. Furthermore, SICs of TC repressed the several genes transcription associated with biofilm formation as determined by real-time quantitative polymerase chain reaction. Overall, our findings suggest that TC could be applied as natural and safe antibiofilm agent to inhibit the biofilm formation of P. aeruginosa.}, } @article {pmid36779720, year = {2023}, author = {Sharma, A and Solis, NV and Huang, MY and Lanni, F and Filler, SG and Mitchell, AP}, title = {Hgc1 Independence of Biofilm Hyphae in Candida albicans.}, journal = {mBio}, volume = {14}, number = {2}, pages = {e0349822}, pmid = {36779720}, issn = {2150-7511}, support = {R01 AI146103/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Mice ; *Candida albicans ; *Fungal Proteins/genetics ; Hyphae/genetics ; Cyclins/genetics ; Biofilms ; Membrane Glycoproteins ; Molecular Chaperones ; }, abstract = {Biofilm and hypha formation are central to virulence of the fungal pathogen Candida albicans. The G1 cyclin gene HGC1 is required for hypha formation under diverse in vitro and in vivo growth conditions. Hgc1 is required for disseminated infection and is a linchpin in the argument that hyphal morphogenesis itself is required for pathogenicity. We report here that HGC1 is dispensable for hypha formation during biofilm formation both in vitro, under strong inducing conditions, and in vivo, in a mouse oropharyngeal candidiasis model. These findings are validated with two or more C. albicans isolates. Systematic screening of overexpressed cyclin genes indicates that CCN1 and CLN3 can compensate partially for Hgc1 function during biofilm growth. This conclusion is also supported by the severity of the hgc1Δ/Δ ccn1Δ/Δ double mutant biofilm defect. Our results suggest that hypha formation in biofilm is accomplished by combined action of multiple cyclins, not solely by Hgc1. IMPORTANCE The HGC1 gene encodes a cyclin that is required for virulence of the fungal pathogen Candida albicans. It is required to produce the elongated hyphal filaments of free-living planktonic cells that are associated with virulence. Here, we show that HGC1 is not required to produce hyphae in the alternative growth form of a biofilm community. We observe Hgc1-independent hyphae in two infection-relevant situations, biofilm growth in vitro and biofilm-like oropharyngeal infection. Our analysis suggests that hypha formation in the biofilm state reflects combined action of multiple cyclins.}, } @article {pmid36779719, year = {2023}, author = {Kher, L and Kelley, K and Santoro, D}, title = {Ultrastructural Analysis of Differences in the Growth and Maturation of Staphylococcus pseudintermedius Biofilm on Biotic and Abiotic Surfaces.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0357722}, pmid = {36779719}, issn = {2165-0497}, abstract = {Biofilms are extremely complex yet systematic microbial structures. Studies comparing the differences in their growth on living and nonliving surfaces by electron microscopy are limited. Therefore, the purpose of this study was to ultrastructurally investigate the differences in the growth and development of Staphylococcal biofilm on polycarbonate filters and canine skin explants. Using scanning and transmission electron microscopy (SEM and TEM), Staphylococcus pseudintermedius was incubated for 6, 12, 24, 48, and 72 h. It was observed that similar amounts of exopolymeric substance (EPS) were deposited on the biofilm on both surfaces, but the biofilm on the skin explants was primarily flat, whereas the biofilm on the membrane developed a multilayered plateaued look. Microcolony formation was only observed on the membrane filter during the early stages of biofilm development. On the membrane biofilms, EPS was observed to be deposited in a distinctive pattern. EPS deposition on the membrane surface was observed to peak before it declined, but on the explant, a constant increase was observed at all time points. Cell exposure to the environment on both the membrane filters and explants differed depending on the stage of biofilm formation. On both the membranes and the skin explants, there was a perceptible difference between the biofilm growth patterns and speeds. The results of this study suggest that data extrapolated from studies on biofilm bactericidal compounds performed on abiotic surfaces (such as polycarbonate filters) may not be entirely applicable to biofilm growing on biotic surfaces (e.g., skin) due to ultrastructural variations revealed in this study. IMPORTANCE Biofilm has been recognized as an important source of antimicrobial resistance. These sessile microbial colonies tend to attach and grow on every surface, biotic and abiotic, and they account for approximately 80% of chronic and recurrent infections. Biofilms are not all alike; they have different structures and microbial compositions. This high variability allows for differences in the production of exopolymer substances, affecting antimicrobial penetration. No studies have been published that simultaneously compare the structure of biofilms grown on abiotic (in vitro) and biotic (ex vivo) surfaces. To identify treatment alternatives, it is essential to understand the differences between biofilms. The results of the study show how biofilm structures and compositions are dependent on the substrate on which they grow.}, } @article {pmid36778889, year = {2023}, author = {Sanchez-Alonso, P and Cobos-Justo, E and Avalos-Rangel, MA and López-Reyes, L and Paniagua-Contreras, GL and Vaca-Paniagua, F and Anastacio-Marcelino, E and López-Ochoa, AJ and Pérez Marquez, VM and Negrete-Abascal, E and Vázquez-Cruz, C}, title = {A Maverick-like cluster in the genome of a pathogenic, moderately virulent strain of Gallibacterium anatis, ESV200, a transient biofilm producer.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {1084766}, pmid = {36778889}, issn = {1664-302X}, abstract = {INTRODUCTION: Gallibacterium anatis causes gallibacteriosis in birds. These bacteria produce biofilms and secrete several fimbrial appendages as tools to cause disease in animals. G. anatis strains contain up to three types of fimbriae. Complete genome sequencing is the strategy currently used to determine variations in the gene content of G. anatis, although today only the completely circularized genome of G. anatis UMN179 is available.

METHODS: The appearance of growth of various strains of G. anatis in liquid culture medium was studied. Biofilm production and how the amount of biofilm was affected by DNase, Proteinase K, and Pronase E enzymes were analyzed. Fimbrial gene expression was performed by protein analysis and qRT-PCR. In an avian model, the pathogenesis generated by the strains G. anatis ESV200 and 12656-12 was investigated. Using bioinformatic tools, the complete genome of G. anatis ESV200 was comparatively studied to search for virulence factors that would help explain the pathogenic behavior of this strain.

RESULTS AND DISCUSSION: G. anatis ESV200 strain differs from the 12656-12 strain because it produces a biofilm at 20%. G. anatis ESV200 strain express fimbrial genes and produces biofilm but with a different structure than that observed for strain 12656-12. ESV200 and 12656-12 strains are pathogenic for chickens, although the latter is the most virulent. Here, we show that the complete genome of the ESV200 strain is similar to that of the UNM179 strain. However, these strains have evolved with many structural rearrangements; the most striking chromosomal arrangement is a Maverick-like element present in the ESV200 strain.}, } @article {pmid36775169, year = {2023}, author = {Kim, HS and Ham, SY and Ryoo, HS and Kim, DH and Yun, ET and Park, HD and Park, JH}, title = {Inhibiting bacterial biofilm formation by stimulating c-di-GMP regulation using citrus peel extract from Jeju Island.}, journal = {The Science of the total environment}, volume = {872}, number = {}, pages = {162180}, doi = {10.1016/j.scitotenv.2023.162180}, pmid = {36775169}, issn = {1879-1026}, mesh = {Bacteria ; *Bacterial Proteins ; Biofilms ; *Cyclic GMP ; }, abstract = {Biofilms consist of single or multiple species of bacteria embedded in extracellular polymeric substances (EPSs), which affect the increase in antibiotic resistance by restricting the transport of antibiotics to the bacterial cells. An alternative approach to treatment with antimicrobial agents is using biofilm inhibitors that regulate biofilm development without inhibiting bacterial growth. In this study, we found that citrus peel extract from Jeju Island (CPEJ) can inhibit bacterial biofilm formation. According to the results, CPEJ concentration-dependently reduces biofilm formation without affecting bacterial growth. Additionally, CPEJ decreased the production of extracellular polymeric substances but increased bacterial swarming motility. These results led to the hypothesis that CPEJ can reduce intracellular bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) concentration. The results showed that CPEJ significantly reduced the c-di-GMP level through increased phosphodiesterase activity. Altogether, these findings suggest that CPEJ as a biofilm inhibitor has new potential for pharmacological (e.g. drug and medication) and industrial applications (e.g. ship hulls, water pipes, and membrane processes biofouling control).}, } @article {pmid36773754, year = {2023}, author = {Minhaco, VMTR and Maquera Huacho, PM and Mancim Imbriani, MJ and Tonon, CC and Chorilli, M and Rastelli, ANS and Spolidorio, DMP}, title = {Improving antimicrobial activity against endodontic biofilm after exposure to blue light-activated novel curcumin nanoparticle.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {42}, number = {}, pages = {103322}, doi = {10.1016/j.pdpdt.2023.103322}, pmid = {36773754}, issn = {1873-1597}, abstract = {New therapies involving natural products and nanobiotechnology open additional perspectives to reduce endodontic infections. Curcumin is a natural polyphenol extracted from the dry rhizome of curcuma long Linn with therapeutic properties for application in nanobiotechnology and as a photosensitizer for photodynamic therapy. This study aimed to synthesize a novel polymeric nanoparticle of poly (lactic-co-glycolic acid) (PLGA) loaded with curcumin (NP+Cur), and evaluate its antimicrobial activity against endodontic biofilms. Additionally, its biocompatibility using oral keratinocytes was assessed. The polymeric NP+Cur was prepared by the nanoprecipitation method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were calculated for the three endodontic bacteria (Enterococcus faecalis, Streptococcus oralis and Actinomyces viscosus). Antibacterial activity of NP+Cur against single- and multispecies biofilm pre-formed on the botton 24-well plate and into dentin tubules of bovine teeth were evaluated by colony forming units and confocal laser scanning microscopy. The pre-irradiation time was 5 min followed by exposure to blue light-emitting diode at 450 nm for the photodynamic treatment. Cell viability using oral keratinocytes was assessed by Alamar Blue assay. MIC and MBC showed antibacterial activity of NP+Cur against endodontic bacteria. A treatment of pre-formed biofilms of endodontic bacteria with NP+Cur also significantly decreased bacterial viability. The concentration of 325 μg/mL of photoactivated NP+Cur was the one that most reduced the viability of the endodontic bacteria evaluated. Regarding biocompatibility, NP+Cur 325 μg/mL and pure nanoparticles showed a cell viability greater than 80%. The novel polymeric nanoparticles loaded with curcumin may be a promising adjunct use to treatment of endodontic infections.}, } @article {pmid36773634, year = {2023}, author = {Shankar, S and Murthy, AN and Rachitha, P and Raghavendra, VB and Sunayana, N and Chinnathambi, A and Alharbi, SA and Basavegowda, N and Brindhadevi, K and Pugazhendhi, A}, title = {Silk sericin conjugated magnesium oxide nanoparticles for its antioxidant, anti-aging, and anti-biofilm activities.}, journal = {Environmental research}, volume = {223}, number = {}, pages = {115421}, doi = {10.1016/j.envres.2023.115421}, pmid = {36773634}, issn = {1096-0953}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; Antioxidants/pharmacology ; Magnesium Oxide/pharmacology ; *Metal Nanoparticles ; *Nanoparticles ; *Sericins ; Spectroscopy, Fourier Transform Infrared ; Biofilms ; }, abstract = {The Silk sericin protein was conjugated with magnesium oxide (MgO) nanoparticles to form SS-MgO-NPs . UV, XRD, FTIR, SEM, DLS, and EDX were used to confirm the formation of SS-MgO-NPs. The absorption band of SS-MgO-NPs using UV-visible spectra was observed at 310 nm, with an average size of the nanoparticles was 65-88 nm analyzed from DLS. The presence of alcohol, CN, and CC, alkanes, alkenes, and cis alkenes, in silk sericin, is confirmed by FT-IR and may act as a stabilizing agent. Later SS-MgO-NPs were evaluated for antioxidant, antibacterial, anti-biofilm, ,anti-aging, and anticancer properties. The SS-MgO-NPs inhibited the formation of biofilm of Pseudomonas aeruginosa and Bacillus cereus. The blood compatibility of SS-MgO-NPs, delaying coagulation was observed using human, blood, and goat blood samples. The SS-MgO-NPs exhibited significant anticancer activity on MCF-7 (IC50 207.6 μg/mL) cancer cell lines. Correspondingly, SS-MgO-NPs demonstrated dose-dependent inhibition of the enzymes in the following order collagenase > elastase > tyrosinase > hyaluronidase, with IC50 values of 75.3, 85.3, 133.6, and 156.3 μgmL[-1], respectively. This exhibits the compoundposses anti-aging properties. So, in in vitro settings, SS-MgO-NPs can be used as an antibacterial, anti-aging, and anticancer agent. Additionally, in vivo research is necessary to validate its therapeutic applications.}, } @article {pmid36773196, year = {2023}, author = {Li, J and Li, Z and Xie, J and Xia, Y and Gong, W and Tian, J and Zhang, K and Yu, E and Wang, G}, title = {Quorum-quenching potential of recombinant PvdQ-engineered bacteria for biofilm formation.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {36773196}, issn = {1618-1905}, support = {31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 31802348//National Natural Science Foundation of China 412 (grant number 31802348)./ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2022XT0503//Central Public-interest Scientific Institution Basal Research Fund, CAFS (grant number 2022XT0503)/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; 2021A1515011116//Guangdong Basic and Applied Basic Research Foundation (grant number 2021A1515011116/ ; }, abstract = {Quorum sensing (QS) is a core mechanism for bacteria to regulate biofilm formation, and therefore, QS inhibition or quorum quenching (QQ) is used as an effective and economically feasible strategy against biofilms. In this study, the PvdQ gene encoding AHL acylase was introduced into Escherichia coli (DE3), and a PvdQ-engineered bacterium with highly efficient QQ activity was obtained and used to inhibit biofilm formation. Gene sequencing and western blot analysis showed that the recombinant pET-PvdQ strain was successfully constructed. The color reaction of Agrobacterium tumefaciens A136 indicated that PvdQ engineering bacteria had shown strong AHL signal molecule quenching activity and significantly inhibited the adhesion (motility) of Pseudomonas aeruginosa and biofilm formation of activated sludge bacteria in Membrane Bio-Reactor (MBR; inhibition rate 51-85%, p < 0.05). In addition, qRT-PCR testing revealed that recombinant PvdQ acylase significantly reduced the transcription level of QS biofilm formation-related genes (cdrA, pqsA, and lasR; p < 0.05). In this study, QQ genetically engineered bacteria enhanced by genetic engineering could effectively inhibit the QS signal transduction mechanism and have the potential to control biofilm formation of pathogenic bacteria in the aquaculture environment, providing an environmentally friendly and alternative antibiotic strategy to suppress biofilm contamination.}, } @article {pmid36770342, year = {2023}, author = {Sousa-Cardoso, F and Teixeira-Santos, R and Campos, AF and Lima, M and Gomes, LC and Soares, OSGP and Mergulhão, FJ}, title = {Graphene-Based Coating to Mitigate Biofilm Development in Marine Environments.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {13}, number = {3}, pages = {}, pmid = {36770342}, issn = {2079-4991}, support = {LA/P/0045/2020 (ALiCE), UIDB/00511/2020, UIDP/00511/2020 (LEPABE), UIDB/50020/2020, UIDP/50020/2020 (LSRE-LCM)//FCT/MCTES (PIDDAC)/ ; PORTUGAL 2020 Partnership Agreement//HealthyWaters (NORTE-01-0145-FEDER-000069)/ ; PTDC/CTMCOM/4844/2020 (NanoCAT)//FCT/MCTES (PIDDAC)/ ; CA20130//EURO-MIC COST Action/ ; }, abstract = {Due to its several economic and ecological consequences, biofouling is a widely recognized concern in the marine sector. The search for non-biocide-release antifouling coatings has been on the rise, with carbon-nanocoated surfaces showing promising activity. This work aimed to study the impact of pristine graphene nanoplatelets (GNP) on biofilm development through the representative marine bacteria Cobetia marina and to investigate the antibacterial mechanisms of action of this material. For this purpose, a flow cytometric analysis was performed and a GNP/polydimethylsiloxane (PDMS) surface containing 5 wt% GNP (G5/PDMS) was produced, characterized, and assessed regarding its biofilm mitigation potential over 42 days in controlled hydrodynamic conditions that mimic marine environments. Flow cytometry revealed membrane damage, greater metabolic activity, and endogenous reactive oxygen species (ROS) production by C. marina when exposed to GNP 5% (w/v) for 24 h. In addition, C. marina biofilms formed on G5/PDMS showed consistently lower cell count and thickness (up to 43% reductions) than PDMS. Biofilm architecture analysis indicated that mature biofilms developed on the graphene-based surface had fewer empty spaces (34% reduction) and reduced biovolume (25% reduction) compared to PDMS. Overall, the GNP-based surface inhibited C. marina biofilm development, showing promising potential as a marine antifouling coating.}, } @article {pmid36769319, year = {2023}, author = {Bąchor, U and Junka, A and Brożyna, M and Mączyński, M}, title = {The In Vitro Impact of Isoxazole Derivatives on Pathogenic Biofilm and Cytotoxicity of Fibroblast Cell Line.}, journal = {International journal of molecular sciences}, volume = {24}, number = {3}, pages = {}, pmid = {36769319}, issn = {1422-0067}, support = {SUB.D090.22.053//Wroclaw Medical University/ ; }, mesh = {Animals ; *Isoxazoles/pharmacology ; Biofilms ; *Anti-Infective Agents, Local/pharmacology ; Microbial Sensitivity Tests ; Staphylococcus aureus ; Cell Line ; Fibroblasts ; Oxazoles/pharmacology ; Anti-Bacterial Agents/pharmacology ; Pseudomonas aeruginosa ; }, abstract = {The microbial, biofilm-based infections of chronic wounds are one of the major challenges of contemporary medicine. The use of topically administered antiseptic agents is essential to treat wound-infecting microorganisms. Due to observed microbial tolerance/resistance against specific clinically-used antiseptics, the search for new, efficient agents is of pivotal meaning. Therefore, in this work, 15 isoxazole derivatives were scrutinized against leading biofilm wound pathogens Staphylococcus aureus and Pseudomonas aeruginosa, and against Candida albicans fungus. For this purpose, the minimal inhibitory concentration, biofilm reduction in microtitrate plates, modified disk diffusion methods and antibiofilm dressing activity measurement methods were applied. Moreover, the cytotoxicity and cytocompatibility of derivatives was tested toward wound bed-forming cells, referred to as fibroblasts, using normative methods. Obtained results revealed that all isoxazole derivatives displayed antimicrobial activity and low cytotoxic effect, but antimicrobial activity of two derivatives, 2-(cyclohexylamino)-1-(5-nitrothiophen-2-yl)-2-oxoethyl 5-amino-3-methyl-1,2-oxazole-4-carboxylate (PUB9) and 2-(benzylamino)-1-(5-nitrothiophen-2-yl)-2-oxoethyl 5-amino-3-methyl-1,2-oxazole-4-carboxylate (PUB10), was noticeably higher compared to the other compounds analyzed, especially PUB9 with regard to Staphylococcus aureus, with a minimal inhibitory concentration more than x1000 lower compared to the remaining derivatives. The PUB9 and PUB10 derivatives were able to reduce more than 90% of biofilm-forming cells, regardless of the species, displaying at the same time none (PUB9) or moderate (PUB10) cytotoxicity against fibroblasts and high (PUB9) or moderate (PUB10) cytocompatibility against these wound cells. Therefore, taking into consideration the clinical demand for new antiseptic agents for non-healing wound treatment, PUB9 seems to be a promising candidate to be further tested in advanced animal models and later, if satisfactory results are obtained, in the clinical setting.}, } @article {pmid36768310, year = {2023}, author = {Sedghizadeh, PP and Cherian, P and Roshandel, S and Tjokro, N and Chen, C and Junka, AF and Hu, E and Neighbors, J and Pawlak, J and Russell, RGG and McKenna, CE and Ebetino, FH and Sun, S and Sodagar, E}, title = {Real-Time Impedance-Based Monitoring of the Growth and Inhibition of Osteomyelitis Biofilm Pathogen Staphylococcus aureus Treated with Novel Bisphosphonate-Fluoroquinolone Antimicrobial Conjugates.}, journal = {International journal of molecular sciences}, volume = {24}, number = {3}, pages = {}, pmid = {36768310}, issn = {1422-0067}, support = {T90 DE021982/DE/NIDCR NIH HHS/United States ; R41DE025789/NH/NIH HHS/United States ; R42DE025789/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; Staphylococcus aureus ; Diphosphonates/therapeutic use ; Moxifloxacin ; Etidronic Acid/therapeutic use ; Electric Impedance ; Anti-Bacterial Agents/chemistry ; *Staphylococcal Infections/drug therapy ; *Osteomyelitis/drug therapy ; Ciprofloxacin/pharmacology/therapeutic use ; Biofilms ; Durapatite/chemistry ; Microbial Sensitivity Tests ; }, abstract = {Osteomyelitis is a limb- and life-threatening orthopedic infection predominantly caused by Staphylococcus aureus biofilms. Bone infections are extremely challenging to treat clinically. Therefore, we have been designing, synthesizing, and testing novel antibiotic conjugates to target bone infections. This class of conjugates comprises bone-binding bisphosphonates as biochemical vectors for the delivery of antibiotic agents to bone minerals (hydroxyapatite). In the present study, we utilized a real-time impedance-based assay to study the growth of Staphylococcus aureus biofilms over time and to test the antimicrobial efficacy of our novel conjugates on the inhibition of biofilm growth in the presence and absence of hydroxyapatite. We tested early and newer generation quinolone antibiotics (ciprofloxacin, moxifloxacin, sitafloxacin, and nemonoxacin) and several bisphosphonate-conjugated versions of these antibiotics (bisphosphonate-carbamate-sitafloxacin (BCS), bisphosphonate-carbamate-nemonoxacin (BCN), etidronate-carbamate-ciprofloxacin (ECC), and etidronate-carbamate-moxifloxacin (ECX)) and found that they were able to inhibit Staphylococcus aureus biofilms in a dose-dependent manner. Among the conjugates, the greatest antimicrobial efficacy was observed for BCN with an MIC of 1.48 µg/mL. The conjugates demonstrated varying antimicrobial activity depending on the specific antibiotic used for conjugation, the type of bisphosphonate moiety, the chemical conjugation scheme, and the presence or absence of hydroxyapatite. The conjugates designed and tested in this study retained the bone-binding properties of the parent bisphosphonate moiety as confirmed using high-performance liquid chromatography. They also retained the antimicrobial activity of the parent antibiotic in the presence or absence of hydroxyapatite, albeit at lower levels due to the nature of their chemical modification. These findings will aid in the optimization and testing of this novel class of drugs for future applications to pharmacotherapy in osteomyelitis.}, } @article {pmid36768176, year = {2023}, author = {Seegers, CII and Lee, DJ and Zarnovican, P and Kirsch, SH and Müller, R and Haselhorst, T and Routier, FH}, title = {Identification of Compounds Preventing A. fumigatus Biofilm Formation by Inhibition of the Galactosaminogalactan Deacetylase Agd3.}, journal = {International journal of molecular sciences}, volume = {24}, number = {3}, pages = {}, pmid = {36768176}, issn = {1422-0067}, support = {EXC 2155, grant number 390874280//Deutsche Forschungsgemeinschaft/ ; TTU 09.721.//German Center for Infection Research/ ; }, mesh = {Humans ; Dactinomycin ; Imatinib Mesylate ; *Polysaccharides/metabolism ; *Aspergillus fumigatus/metabolism ; Biofilms ; }, abstract = {The opportunistic fungus Aspergillus fumigatus causes a set of diseases ranging from allergy to lethal invasive mycosis. Within the human airways, A. fumigatus is embedded in a biofilm that forms not only a barrier against the host immune defense system, but also creates a physical barrier protecting the fungi from chemicals such as antifungal drugs. Novel therapeutic strategies aim at combining drugs that inhibit biofilm synthesis or disrupt existing biofilm with classical antimicrobials. One of the major constituents of A. fumigatus biofilm is the polysaccharide galactosaminogalactan (GAG) composed of α1,4-linked N-acetylgalactosamine, galactosamine, and galactose residues. GAG is synthesized on the cytosolic face of the plasma membrane and is extruded in the extracellular space, where it is partially deacetylated. The deacetylase Agd3 that mediates this last step is essential for the biofilm formation and full virulence of the fungus. In this work, a previously described enzyme-linked lectin assay, based on the adhesion of deacetylated GAG to negatively charged plates and quantification with biotinylated soybean agglutinin was adapted to screen microbial natural compounds, as well as compounds identified in in silico screening of drug libraries. Actinomycin X2, actinomycin D, rifaximin, and imatinib were shown to inhibit Agd3 activity in vitro. At a concentration of 100 µM, actinomycin D and imatinib showed a clear reduction in the biofilm biomass without affecting the fungal growth. Finally, imatinib reduced the virulence of A. fumigatus in a Galleria mellonella infection model in an Agd3-dependent manner.}, } @article {pmid36766686, year = {2023}, author = {Sanmukh, SG and Admella, J and Moya-Andérico, L and Fehér, T and Arévalo-Jaimes, BV and Blanco-Cabra, N and Torrents, E}, title = {Accessing the In Vivo Efficiency of Clinically Isolated Phages against Uropathogenic and Invasive Biofilm-Forming Escherichia coli Strains for Phage Therapy.}, journal = {Cells}, volume = {12}, number = {3}, pages = {}, pmid = {36766686}, issn = {2073-4409}, mesh = {Animals ; Humans ; *Bacteriophages ; Escherichia coli ; *Phage Therapy ; Anti-Bacterial Agents ; Biofilms ; }, abstract = {Escherichia coli is one of the most common members of the intestinal microbiota. Many of its strains are associated with various inflammatory infections, including urinary or gut infections, especially when displaying antibiotic resistance or in patients with suppressed immune systems. According to recent reports, the biofilm-forming potential of E. coli is a crucial factor for its increased resistance against antibiotics. To overcome the limitations of using antibiotics against resistant E. coli strains, the world is turning once more towards bacteriophage therapy, which is becoming a promising candidate amongst the current personalized approaches to target different bacterial infections. Although matured and persistent biofilms pose a serious challenge to phage therapy, they can still become an effective alternative to antibiotic treatment. Here, we assess the efficiency of clinically isolated phages in phage therapy against representative clinical uropathogenic and invasive biofilm-forming E. coli strains. Our results demonstrate that irrespective of host specificity, bacteriophages producing clear plaques with a high burst size, and exhibiting depolymerizing activity, are good candidates against biofilm-producing E. coli pathogens as verified from our in vitro and in vivo experiments using Galleria mellonella where survival was significantly increased for phage-therapy-treated larvae.}, } @article {pmid36766272, year = {2023}, author = {Ma, K and Wang, H and Lv, Z and Hu, Y and Wang, H and Shu, F and Zhu, C and Xue, T}, title = {The Two-Component System CpxRA Affects Antibiotic Susceptibility and Biofilm Formation in Avian Pathogenic Escherichia coli.}, journal = {Animals : an open access journal from MDPI}, volume = {13}, number = {3}, pages = {}, pmid = {36766272}, issn = {2076-2615}, support = {32270194//National Natural Science Foundation of China/ ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is one of the common extraintestinal infectious disease pathogens in chickens, geese, and other birds. It can cause a variety of infections, and even the death of poultry, causing enormous economic losses. However, the misuse and abuse of antibiotics in the poultry industry have led to the development of drug resistance in the gut microbes, posing a challenge for the treatment of APEC infections. It has been reported that the CpxRA two-component system has an effect on bacterial drug resistance, but the specific regulatory mechanism remains unclear. In this study, the regulatory mechanism of CpxRA on APEC biofilm formation and EmrKY efflux pump was investigated. The cpxRA knockout strain of E. coli APEC40 was constructed, and the molecular regulatory mechanism of CpxR on biofilms and efflux pump-coding genes were identified by biofilm formation assays, drug susceptibility test, real-time reverse transcription quantitative PCR, and electrophoretic mobility shift assay (EMSA). The results indicated that CpxR can directly bind to the promoter region of emrKY and negatively regulate the sensitivity of bacteria to ofloxacin and erythromycin. These results confirm the important regulatory role of the CpxRA two-component system under antibiotic stress in APEC.}, } @article {pmid36764616, year = {2023}, author = {Wang, J and Li, L and Chi, B and Shan, J and Yi, X and Liu, Y and Zhou, H}, title = {Metagenomic insights into the effects of benzyl dodecyl dimethyl ammonium bromide (BDAB) shock on bacteria-driven nitrogen removal in a moving-bed biofilm reactor (MBBR).}, journal = {Chemosphere}, volume = {320}, number = {}, pages = {138098}, doi = {10.1016/j.chemosphere.2023.138098}, pmid = {36764616}, issn = {1879-1298}, mesh = {Humans ; Ammonia/analysis ; Bacteria ; Biofilms ; Bioreactors ; *COVID-19 ; Denitrification ; Nitrogen/analysis ; *Quaternary Ammonium Compounds ; SARS-CoV-2 ; Genomics ; }, abstract = {The use of disinfectants made from quaternary ammonium compounds (QACs) has greatly increased since the outbreak of SARS-CoV-2. However, the effect of QACs on wastewater treatment performance is still unclear. In this study, a commonly used QAC, i.e., benzyl dodecyl dimethyl ammonium bromide (BDAB), was added to a moving-bed biofilm reactor (MBBR) to investigate BDAB's effect on nutrient removal. When the BDAB concentration was increased to 50 mg L[-1], the ammonia removal efficiency (ARE) greatly decreased, as did the nitrate production rate constants (NPR). This inhibition was partly recovered by decreasing the BDAB concentration to 30 mg L[-1]. Metagenomic sequencing revealed the functional genera present during different stages of the control (Rc) and BDAB-added reactors (Re). The enriched genera (Rudaea, Nitrosospira, Sphingomonas, and Rhodanobacter) in Rc mainly related to the nitrogen metabolism, while the enriched genera in Re was BDAB-concentration dependent. Functional genes analysis suggested that a lack of ammonia oxidase-encoding genes (amoABC) may have caused a decrease in ARE in Re, while the efflux pump-encoding genes emrE, mdfA, and oprM and a gene encoding BAC oxygenase (oxyBAC) were responsible for BDAB resistance. The increase in the total abundance of antibiotic resistance genes (ARGs) in Re revealed a potential risk arising from BDAB. Overall, this study revealed the potential effect and ecological risks of BDAB introduction in WWTPs.}, } @article {pmid36764613, year = {2023}, author = {Xu, Y and Gu, Y and Peng, L and Wang, N and Chen, S and Liang, C and Liu, Y and Ni, BJ}, title = {Unravelling ciprofloxacin removal in a nitrifying moving bed biofilm reactor: Biodegradation mechanisms and pathways.}, journal = {Chemosphere}, volume = {320}, number = {}, pages = {138099}, doi = {10.1016/j.chemosphere.2023.138099}, pmid = {36764613}, issn = {1879-1298}, mesh = {*Ciprofloxacin ; *Biofilms ; Bioreactors/microbiology ; Wastewater ; Anti-Bacterial Agents ; Nitrification ; Ammonia/metabolism ; }, abstract = {Although moving bed biofilm reactors (MBBRs) have shown excellent antibiotic removal potentials, the information on underlying mechanisms is yet limited. This work assessed the removal of ciprofloxacin in an enriched nitrifying MBBR by clarifying the contribution of adsorption and microbial-induced biodegradation. Results demonstrated the considerable biomass adsorption (55%) in first 30 min. Limiting nitrite oxidizing bacteria growth or inhibiting nitrification would lead to lower adsorption capacities. The highest ciprofloxacin biodegradation rate constant was 0.082 L g SS[-1] h[-1] in the presence of ammonium, owing to ammonia oxidizing bacteria (AOB)-induced cometabolism, while heterotrophs played an insignificant role (∼9%) in ciprofloxacin biodegradation. The developed model also suggested the importance of AOB-induced cometabolism and metabolism over heterotrophs-induced biodegradation by analyzing the respective biodegradation coefficients. Cometabolic biodegradation pathways of ciprofloxacin mainly involved the piperazine ring cleavage, probably alleviating antimicrobial activities. It implies the feasibility of nitrifying biofilm systems towards efficient antibiotic removal from wastewater.}, } @article {pmid36764542, year = {2023}, author = {Robichon, C and Robin, J and Dolédec, S}, title = {Relative effect of hydraulics, physico-chemistry and other biofilm algae on benthic cyanobacteria assemblages in a regulated river.}, journal = {The Science of the total environment}, volume = {872}, number = {}, pages = {162142}, doi = {10.1016/j.scitotenv.2023.162142}, pmid = {36764542}, issn = {1879-1026}, mesh = {*Rivers/chemistry ; *Cyanobacteria ; Cyanobacteria Toxins ; Biofilms ; }, abstract = {The development of benthic cyanobacteria currently raises concern worldwide because of their potential to produce toxins. As a result, understanding which measures of biotic and abiotic parameters influence the development of cyanobacterial assemblages is of great importance to guide management actions. In this study, we investigate the relative contributions of abiotic and biotic parameters that may drive the development of cyanobacterial assemblages in river biofilms. First, a 2D hydrodynamic model allowed us to retrace changes in depths and velocities according to discharge at a 4 m[2] resolution. From this model, we set up three hydraulic zones in each of the 4 reaches investigated along a 50-km-long river stretch. We further used univariate, multivariate and variance partitioning analyses to assess the contribution of past and present hydraulics, present physical and chemical parameters and algae to the temporal variability of cyanobacterial assemblage composition. The cyanobacterial assemblages were generally dominated by Phormidium sp., Lyngbya sp., Planktolyngbya sp. and Oscillatoria sp., four genera known to contain potentially toxic species. The highest biovolumes of cyanobacteria were present in low velocity zones in early summer and shifted to high velocity zones in late summer, highlighting the major influence of hydraulic parameters on benthic cyanobacteria settlement and development in rivers. Considering the identified genera, biofilms present a potentially high risk of toxin production. Relations between cyanobacterial development, toxin production and environmental parameters need to be further assessed to better estimate this risk.}, } @article {pmid36763802, year = {2023}, author = {Lagudas, MFG and Bureros, KJC}, title = {Inhibition of Candida albicans and Staphylococcus epidermidis mixed biofilm formation in a catheter disk model system treated with EtOH-EDTA solution.}, journal = {Letters in applied microbiology}, volume = {76}, number = {2}, pages = {}, doi = {10.1093/lambio/ovac074}, pmid = {36763802}, issn = {1472-765X}, mesh = {*Candida albicans ; *Ethanol/pharmacology ; Edetic Acid/pharmacology ; Staphylococcus epidermidis ; Catheters ; Biofilms ; }, abstract = {Microbial colonization and the formation of biofilms on catheter surfaces pose a great risk for medical-related infections. We aimed (a) to evaluate polymicrobial biofilm formation of Candida albicans and Staphylococcus epidermidis and (b) to investigate the inhibition and effects of ethanol (EtOH) and EtOH-EDTA solutions on biofilms. Catheter disks were made and used as a substrate for biofilm formation. Varying concentrations of EtOH and EtOH-EDTA solutions were compared in deterring biofilm formation. The EtOH-EDTA solutions were further tested to remove mature and preformed biofilms. Compared to their monospecies counterparts, biofilm concentration significantly increases when C. albicans is co-cultured with S. epidermidis. Moreover, all treatments with EtOH-EDTA solution significantly lowered biofilm formation compared to EtOH alone (P ≤ 0.05). Lastly, biofilm was dramatically reduced when treated with 20%, 30%, 40%, and 50% EtOH-EDTA solutions (P ≤ 0.05). Our findings suggest that biofilms become more resilient to treatment when formed by multiple organisms. Nonetheless, treatment with EtOH-EDTA is effective against these polymicrobial biofilms.}, } @article {pmid36762094, year = {2022}, author = {Li, X and Gu, N and Huang, TY and Zhong, F and Peng, G}, title = {Pseudomonas aeruginosa: A typical biofilm forming pathogen and an emerging but underestimated pathogen in food processing.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1114199}, pmid = {36762094}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is a notorious gram-negative pathogenic microorganism, because of several virulence factors, biofilm forming capability, as well as antimicrobial resistance. In addition, the appearance of antibiotic-resistant strains resulting from the misuse and overuse of antibiotics increases morbidity and mortality in immunocompromised patients. However, it has been underestimated as a foodborne pathogen in various food groups for instance water, milk, meat, fruits, and vegetables. Chemical preservatives that are commonly used to suppress the growth of food source microorganisms can cause problems with food safety. For these reasons, finding effective, healthy safer, and natural alternative antimicrobial agents used in food processing is extremely important. In this review, our ultimate goal is to cover recent advances in food safety related to P. aeruginosa including antimicrobial resistance, major virulence factors, and prevention measures. It is worth noting that food spoilage caused by P. aeruginosa should arouse wide concerns of consumers and food supervision department.}, } @article {pmid36761303, year = {2023}, author = {Burden, B and Rodriguez-Alvarez, JS and Levi, N and Gayzik, FS}, title = {Application of survival analysis to model proliferation likelihood of Escherichia coli biofilm following laser-induced hyperthermia treatment.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1001017}, pmid = {36761303}, issn = {2296-4185}, abstract = {Eighty percent of bacterial infections associated with living tissue and medical devices are linked to drug-resistant biofilms, leading to lengthy and costly recoveries. Laser-induced hyperthermia can disrupt cell proliferation within biofilms and increase susceptibility to antibiotics. However, there can be bacterial survival differences dependent upon laser irradiation times, and prolonged time at elevated temperature can damage healthy tissue. The objective of this study was to use survival analysis to model the impact of temperature increases on reducing viable biofilm bacteria. In vitro biofilms of Escherichia coli were grown on silicone discs or silicone doped with photothermal poly(3,4-ethylenedioxythiophene) hydrate (PEDOT) nanotubes, and subjected to laser-induced hyperthermia, using a 3 W continuous wave laser at 800 nm for varying times. The number of colony forming units per milliliter (CFU/mL) and maximum temperature were measured after each trial. Survival analysis was employed to estimate bacterial cell proliferation post-treatment to provide a quantitative framework for future studies evaluating photothermal inactivation of bacterial biofilms. The results demonstrate the first application of survival analysis for predicting the likelihood of bacterial cell proliferation based on temperature.}, } @article {pmid36756936, year = {2023}, author = {Rao, TS and Feser, R}, title = {Biofilm formation by sulphate-reducing bacteria on different metals and their prospective role in titanium corrosion.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-14}, doi = {10.1080/09593330.2023.2178976}, pmid = {36756936}, issn = {1479-487X}, abstract = {This study describes the biofilm formation by sulphate-reducing bacteria (SRB) on different materials, which has implications for the biomedical, pharmaceutical, food and chemical process industries. SRB was chosen as a model organism being an anaerobic bacterium. Biofilm formation on different materials and corrosion of titanium by SRB were monitored with time using confocal laser scanning microscopy and fluorescent FISH probes were used to authenticate the SRB strain. The thickness of the mono-culture SRB biofilm has ranged from 4 to 24 µm during thed 12-84 hr; however, the maximum biofilm thickness (24 µm) was recorded after 60 hr of growth. Planktonic growth of the SRB strain showed a log phase up to 48 hr and the sulphide production ranged from 2 to 14 mg l[-1]. For a comparative account, the SRB biofilm formation on copper was chosen as a positive control. Finally, the putative role of extracellular electron transfer by SRB in the biocorrosion process and the plausible mechanism of pitting corrosion of titanium is described in detail.}, } @article {pmid36756619, year = {2023}, author = {de Melo, CC and de Sousa, BR and da Costa, GL and Oliveira, MME and de Lima-Neto, RG}, title = {Colonized patients by Candida auris: Third and largest outbreak in Brazil and impact of biofilm formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1033707}, pmid = {36756619}, issn = {2235-2988}, mesh = {Humans ; *Antifungal Agents ; Candida auris ; Brazil/epidemiology ; Proteomics ; *COVID-19 ; SARS-CoV-2 ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {OBJECTIVE: To describe the clinical-epidemiological features of patients colonized by Candida auris in the largest outbreak in Brazil and to show the biofilm formation capacity of yeast strains.

METHODS: Clinical yeasts suspected of C. auris isolated from urine and surveillance samples were seeded on chromogenic media at 30°C and Sabouraud agar at 42°C. matrix-assisted laser desorption/ionization-time of flight mass spectometry was used for reliable identification. After proteomic confirmation, the genomic approach and culture on Chromagar Candida Plus media were carried out. Biofilm formation was investigated based on metabolic activity, and the clinical-epidemiological profile of patients was described.

RESULTS: A total of 11 C. auris clinical yeasts from nine patients were identified between the end of December 2021 and March 2022. Two clinical yeasts were isolates from urine and nine clinical yeasts were isolates from axillary and inguinal surveillance swabs. No case is related to previous Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, all the yeasts showed a high ability of biofilm formation.

CONCLUSION: C. auris requires great vigilance as its high capacity to colonize and form biofilms contributes to its dissemination. The rapid and precise identification of this species is essential for the management, control, and prevention of infections.}, } @article {pmid36756618, year = {2023}, author = {Zaki, BM and Fahmy, NA and Aziz, RK and Samir, R and El-Shibiny, A}, title = {Characterization and comprehensive genome analysis of novel bacteriophage, vB_Kpn_ZCKp20p, with lytic and anti-biofilm potential against clinical multidrug-resistant Klebsiella pneumoniae.}, journal = {Frontiers in cellular and infection microbiology}, volume = {13}, number = {}, pages = {1077995}, pmid = {36756618}, issn = {2235-2988}, mesh = {Humans ; *Bacteriophages/genetics ; Klebsiella pneumoniae/genetics ; Phylogeny ; Genomics ; Anti-Bacterial Agents/pharmacology ; Genome, Viral ; Biofilms ; }, abstract = {INTRODUCTION: The rise of infections by antibiotic-resistant bacterial pathogens is alarming. Among these, Klebsiella pneumoniae is a leading cause of death by hospital-acquired infections, and its multidrug-resistant strains are flagged as a global threat to human health, which necessitates finding novel antibiotics or alternative therapies. One promising therapeutic alternative is the use of virulent bacteriophages, which specifically target bacteria and coevolve with them to overcome potential resistance. Here, we aimed to discover specific bacteriophages with therapeutic potential against multiresistant K. pneumoniae clinical isolates.

METHODS AND RESULTS: Out of six bacteriophages that we isolated from urban and medical sewage, phage vB_Kpn_ZCKp20p had the broadest host range and was thus characterized in detail. Transmission electron microscopy suggests vB_Kpn_ZCKp20p to be a tailed phage of the siphoviral morphotype. In vitro evaluation indicated a high lytic efficiency (30 min latent period and burst size of ∼100 PFU/cell), and extended stability at temperatures up to 70°C and a wide range of (2-12) pH. Additionally, phage vB_Kpn_ZCKp20p possesses antibiofilm activity that was evaluated by the crystal violet assay and was not cytotoxic to human skin fibroblasts. The whole genome was sequenced and annotated, uncovering one tRNA gene and 33 genes encoding proteins with assigned functions out of 85 predicted genes. Furthermore, comparative genomics and phylogenetic analysis suggest that vB_Kpn_ZCKp20p most likely represents a new species, but belongs to the same genus as Klebsiella phages ZCKP8 and 6691. Comprehensive genomic and bioinformatics analyses substantiate the safety of the phage and its strictly lytic lifestyle.

CONCLUSION: Phage vB_Kpn_ZCKp20p is a novel phage with potential to be used against biofilm-forming K. pneumoniae and could be a promising source for antibacterial and antibiofilm products, which will be individually studied experimentally in future studies.}, } @article {pmid36756165, year = {2022}, author = {Rychshanova, R and Mendybayeva, A and Miciński, B and Mamiyev, N and Shevchenko, P and Bermukhametov, Z and Orzechowski, B and Miciński, J}, title = {Antibiotic resistance and biofilm formation in Staphylococcus aureus isolated from dairy cows at the stage of subclinical mastitis in northern Kazakhstan.}, journal = {Archives animal breeding}, volume = {65}, number = {4}, pages = {439-448}, pmid = {36756165}, issn = {2363-9822}, abstract = {Staphylococcus aureus is an important causative agent of subclinical bovine mastitis worldwide. The aim of this research was to study the ability of S. aureus to form biofilms. Additionally, we examined the genes involved in cell resistance and sensitivity to antibiotics. Samples were collected from December 2020 to May 2021 from Simmental and black-and-white cows. The study was carried out on a total number of 643 cows, of which 278 (23 %) were in the subclinical mastitis stage. Finally, 64 S. aureus isolates were isolated and identified. The highest level of phenotypic resistance was observed to antibiotics of the tetracycline (tetracycline - 48.4 %, doxycycline - 32.8 %) and β -lactam (ampicillin - 45.3 %, penicillin - 45.3 %) groups. The genes encoding antibiotic resistance were characterized with the polymerase chain reaction method: blaZ in 30 isolates, mecA in 1 isolate, ermC in 15 isolates, aph (3) in 2 isolates, tetK in 19 isolates, tetM in 9 isolates. The tested S. aureus isolates had the ability to form biofilms in 76.6 % (49 / 64) of cases. Of these, 69.4 % were resistant to at least one antibiotic. The obtained results have shown that S. aureus, identified in cows with subclinical mastitis, was resistant mainly to tetracycline and β -lactam antibiotics. In addition, S. aureus isolates expressed resistance genes to the above drugs and had the ability to form biofilm. This study will help to identify the extent of antibiotic resistance and monitor S. aureus contamination of raw milk.}, } @article {pmid36755419, year = {2023}, author = {Khari, A and Biswas, B and Gangwar, G and Thakur, A and Puria, R}, title = {Candida auris biofilm: a review on model to mechanism conservation.}, journal = {Expert review of anti-infective therapy}, volume = {21}, number = {3}, pages = {295-308}, doi = {10.1080/14787210.2023.2179036}, pmid = {36755419}, issn = {1744-8336}, mesh = {Humans ; *Candida/physiology ; *Candida auris ; Reproducibility of Results ; Saccharomyces cerevisiae ; Biofilms ; Candida albicans ; Antifungal Agents/pharmacology ; }, abstract = {INTRODUCTION: Candida auris is included in the fungal infection category 'critical' by WHO because of associated high drug tolerance and spread at an alarming rate which if remains untouched may result in serious outbreaks. Since its discovery in 2009, several assiduous efforts by mycologists across the world have deciphered its biology including growth physiology, drug tolerance, biofilm formation, etc. The differential response of various strains from different clades poses a hurdle in drawing a final conclusion.

AREAS COVERED: This review provides brief insights into the understanding of C. auris biofilm. It includes information on various models developed to understand the biofilms and conservation of different signaling pathways. Significant development has been made in the recent past with the generation of relevant in vivo and ex vivo models. The role of signaling pathways in the development of biofilm is largely unknown.

EXPERT OPINION: The selection of an appropriate model system is a must for the accuracy and reproducibility of results. The conservation of major signaling pathways in C. auris with respect to C. albicans and S. cerevisiae highlights that initial inputs acquired from orthologs will be valuable in getting insights into the mechanism of biofilm formation and associated pathogenesis.}, } @article {pmid36754199, year = {2023}, author = {Yan, C and Li, X and Huang, J and Cao, C and Ji, X and Qian, X and Wei, Z}, title = {Long-term synergic removal performance of N, P, and CuO nanoparticles in constructed wetlands along with temporal record of Cu pollution in substrate-biofilm.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {322}, number = {}, pages = {121231}, doi = {10.1016/j.envpol.2023.121231}, pmid = {36754199}, issn = {1873-6424}, mesh = {Waste Disposal, Fluid ; Wetlands ; Sand ; *Nanoparticles/toxicity ; Wastewater ; Copper/toxicity/analysis ; Bacteria ; Biofilms ; *Environmental Pollutants/analysis ; *Metal Nanoparticles/toxicity ; }, abstract = {With continued exposure to CuO nanoparticles (NPs) which were toxic to organisms, the performance of wastewater treatment facility might be affected. In present study, the feasibility of constructed wetlands (CWs) for wastewater treatment containing CuO NPs and common pollutants was comprehensively explored. It was found that CWs removed 98.80-99.84% CuO NPs and 90.91-91.83% COD within 300 days. However, N and P removals were affected to varying degrees by CuO NPs. N removal was inhibited only by 0.5 mg/L CuO NPs with 19.75% decreases on the mean from day 200-300. P removal was reduced by 3.80-50.75% and 1.92-7.19% under exposure of 0.5 and 5 mg/L CuO NPs throughout the experiment. Moreover, CuO NPs changed the adsorption potential of P and ammonium-N on sand-biofilm. Cu concentrations in spatial distribution decreased, while they in temporal distribution increased from 36.94 to 97.78 μg/g and from 70.92 to 282.66 μg/g at middle sand layer exposed to 0.5 and 5 mg/L CuO NPs. Mass balance model showed that substrate-biofilm was main pollutant sink for CuO NPs, N, and P. The minor Cu was absorbed by plants exposed to 0.5 and 5 mg/L CuO NPs, which decreased N by 53.40% and 18.51%，and P by 52.35% and 21.62%. Sequencing analysis indicated that CuO NPs also altered spatial microbial community. N-degrading bacteria (Rhodanobacter, Thauera, Nitrospira) changed differently, while phosphate accumulation organisms (Acinetobacter, Pseudomonas, Microlunatus) reduced. Overall, the negative effects of CuO NPs on N and P removal should be noted when CWs as ecological technologies are used to treat CuO NPs-containing wastewater.}, } @article {pmid36753070, year = {2023}, author = {Marin-Dett, FH and Campanella, JEM and Trovatti, E and Bertolini, MC and Vergani, CE and Barbugli, PA}, title = {Extracellular lipids of Candida albicans biofilm induce lipid droplet formation and decreased response to a topoisomerase I inhibitor in dysplastic and neoplastic oral cells.}, journal = {Journal of applied oral science : revista FOB}, volume = {30}, number = {}, pages = {e20220319}, doi = {10.1590/1678-7757-2022-0319}, pmid = {36753070}, issn = {1678-7765}, mesh = {*Candida albicans ; *Topoisomerase I Inhibitors/pharmacology ; Lipid Droplets ; Biofilms ; Lipids/pharmacology ; }, abstract = {OBJECTIVE: Some microorganisms, i.e., Candida albicans, have been associated with cancer onset and development, although whether the fungus promotes cancer or whether cancer facilitates the growth of C. albicans is unclear. In this context, microbial-derived molecules can modulate the growth and resistance of cancer cells. This study isolated extracellular lipids (ECL) from a 36-h Candida albicans biofilm incubated with oral dysplastic (DOK) and neoplastic (SCC 25) cells, which were further challenged with the topoisomerase I inhibitor camptothecin (CPT), a lipophilic anti-tumoral molecule.

METHODOLOGY: ECL were extracted from a 36-h Candida albicans biofilm with the methanol/chloroform precipitation method and identified with Nuclear Magnetic Resonance (1H-NMR). The MTT tetrazolium assay measured ECL cytotoxicity in DOK and SCC 25 cells, alamarBlue™ assessed cell metabolism, flow cytometry measured cell cycle, and confocal microscopy determined intracellular features.

RESULTS: Three major classes of ECL of C. albicans biofilm were found: phosphatidylinositol (PI), phosphatidylcholine (PC), and phosphatidylglycerol (PG). The ECL of C. albicans biofilm had no cytotoxic effect on neither cell after 24 hours, with a tendency to disturb the SCC 25 cell cycle profile (without statistical significance). The ECL-induced intracellular lipid droplet (LD) formation on both cell lines after 72 hours. In this context, ECL enhanced cell metabolism, decreased the response to CPT, and modified intracellular drug distribution.

CONCLUSION: The ECL (PI, PC, and PG) of 36-h Candida albicans biofilm directly interacts with dysplastic and neoplastic oral cells, highlighting the relevance of better understanding C. albicans biofilm signaling in the microenvironment of tumor cells.}, } @article {pmid36749305, year = {2023}, author = {Samadi, A and Kermanshahi Pour, A and Beims, RF and Xu, CC}, title = {Delignified porous wood as biofilm support for 1,4-dioxane-degrading bacterial consortium.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/09593330.2023.2178330}, pmid = {36749305}, issn = {1479-487X}, abstract = {Delignified porous wood samples were used as carriers for biofilm formation of a bacterial consortium with the ability to degrade 1,4-dioxane (DX). The delignification treatment of the natural wood resulted in higher porosity, formation of macropores, increase in surface roughness and hydrophilicity of the treated wood pieces. These superior properties of two types of treated carriers (respectively, A and B) compared to the untreated wood resulted in 2.19 ± 0.52- and 2.66 ± 0.23-fold higher growth of biofilm. Moreover, analysis of the fatty acid profiles indicated an increase in proportion of the saturated fatty acids during the biofilm formation, characterising an enhancement in rigidity and hydrophobicity of the biofilms. DX initial concentration of 100 mg/L was completely degraded (detection limit 0.01 mg/L) in 24 and 32 h using the treated A and B woods, while only 25.84 ± 5.95% was removed after 32 h using the untreated wood. However, fitting the DX biodegradation data to the Monod model showed a lower maximum specific growth rate for biofilm (0.0276 ± 0.0018 1/h) versus planktonic (0.0382 ± 0.0024 1/h), because of gradual accumulation of inactive cells in the biofilm. Findings of this study can contribute to the knowledge of biofilm formation regarding the physical/chemical properties of biofilm carriers and be helpful to the ongoing research on bioremediation of DX.}, } @article {pmid36749062, year = {2023}, author = {Tello-Díaz, C and Palau, M and Muñoz, E and Gomis, X and Gavaldà, J and Fernández-Hidalgo, N and Bellmunt-Montoya, S}, title = {Methicillin-Susceptible Staphylococcus aureus Biofilm Formation on Vascular Grafts: an In Vitro Study.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0393122}, pmid = {36749062}, issn = {2165-0497}, abstract = {The aim of this study was to quantify in vitro biofilm formation by methicillin-susceptible Staphylococcus aureus (MSSA) on the surfaces of different types of commonly used vascular grafts. We performed an in vitro study with two clinical strains of MSSA (MSSA2 and MSSA6) and nine vascular grafts: Dacron (Hemagard), Dacron-heparin (Intergard heparin), Dacron-silver (Intergard Silver), Dacron-silver-triclosan (Intergard Synergy), Dacron-gelatin (Gelsoft Plus), Dacron plus polytetrafluoroethylene (Fusion), polytetrafluoroethylene (Propaten; Gore), Omniflow II, and bovine pericardium (XenoSure). Biofilm formation was induced in two phases: an initial 90-minute adherence phase and a 24-hour growth phase. Quantitative cultures were performed, and the results were expressed as log10 CFU per milliliter. The Dacron-silver-triclosan graft and Omniflow II were associated with the least biofilm formation by both MSSA2 and MSSA6. MSSA2 did not form a biofilm on the Dacron-silver-triclosan graft (0 CFU/mL), and the mean count on the Omniflow II graft was 3.89 CFU/mL (standard deviation [SD] 2.10). The mean count for the other grafts was 7.01 CFU/mL (SD 0.82). MSSA6 formed a biofilm on both grafts, with 2.42 CFU/mL (SD 2.44) on the Dacron-silver-triclosan graft and 3.62 CFU/mL (SD 2.21) on the Omniflow II. The mean biofilm growth on the remaining grafts was 7.33 CFU/mL (SD 0.28). The differences in biofilm formation on the Dacron-silver-triclosan and Omniflow II grafts compared to the other tested grafts were statistically significant. Our findings suggest that of the vascular grafts we studied, the Dacron-silver-triclosan and Omniflow II grafts might prevent biofilm formation by MSSA. Although further studies are needed, these grafts seem to be good candidates for clinical use in vascular surgeries at high risk of infections due to this microorganism. IMPORTANCE The Dacron silver-triclosan and Omniflow II vascular grafts showed the greatest resistance to in vitro methicillin-susceptible Staphylococcus aureus biofilm formation compared to other vascular grafts. These findings could allow us to choose the most resistant to infection prosthetic graft.}, } @article {pmid36748569, year = {2023}, author = {Chávez-Jacobo, VM and Becerra-Rivera, VA and Guerrero, G and Dunn, MF}, title = {The Sinorhizobium meliloti NspS-MbaA system affects biofilm formation, exopolysaccharide production and motility in response to specific polyamines.}, journal = {Microbiology (Reading, England)}, volume = {169}, number = {1}, pages = {}, pmid = {36748569}, issn = {1465-2080}, mesh = {*Polyamines/metabolism ; *Sinorhizobium meliloti/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Polysaccharides, Bacterial/metabolism ; }, abstract = {We previously showed that specific polyamines (PAs) present in the extracellular environment markedly affect extracellular polysaccharide (EPS) production, biofilm formation and motility in Sinorhizobium meliloti Rm8530. We hypothesized that extracellular PA signals were sensed and transduced by the NspS and MbaA proteins, respectively, which are homologs of the PA-sensing, c-di-GMP modulating NspS-MbaA proteins described in Vibrio cholerae. Here we show that the decrease in biofilm formation and EPS production in the quorum-sensing (QS)-deficient S. meliloti wild-type strain 1021 in cultures containing putrescine or spermine did not occur in a 1021 nspS mutant (1021 nspS). The transcriptional expression of nspS in strain 1021 was significantly increased in cultures containing either of these polyamines, but not by exogenous cadaverine, 1,3-diaminopropane (DAP), spermidine (Spd) or norspermidine (NSpd). Cell aggregation in liquid cultures did not differ markedly between strain 1021 and 1021 nspS in the presence or absence of PAs. The S. meliloti QS-proficient Rm8530 wild-type and nspS mutant (Rm8530 nspS) produced similar levels of biofilm under control conditions and 3.2- and 2.2-fold more biofilm, respectively, in cultures with NSpd, but these changes did not correlate with EPS production. Cells of Rm8530 nspS aggregated from two- to several-fold more than the wild-type in cultures without PAs or in those containing Spm. NSpd, Spd and DAP differently affected swimming and swarming motility in strains 1021 and Rm8530 and their respective nspS mutants. nspS transcription in strain Rm8530 was greatly reduced by exogenous Spm. Bioinformatic analysis revealed similar secondary structures and functional domains in the MbaA proteins of S. meliloti and V. cholerae, while their NspS proteins differed in some residues implicated in polyamine recognition in the latter species. NspS-MbaA homologs occur in a small subset of soil and aquatic bacterial species that commonly interact with eukaryotes. We speculate that the S. meliloti NspS-MbaA system modulates biofilm formation, EPS production and motility in response to environmental or host plant-produced PAs.}, } @article {pmid36748557, year = {2022}, author = {Abdian, PL and Malori, MS and Caramelo, JJ and Checchi, AM and Russo, DM and Zorreguieta, A and Berretta, MF and Benintende, G}, title = {Fusion of a bacterial cadherin-like domain and green fluorescent protein as a specific probe to study biofilm matrix formation in Rhizobium spp.}, journal = {Microbiology (Reading, England)}, volume = {168}, number = {12}, pages = {}, doi = {10.1099/mic.0.001284}, pmid = {36748557}, issn = {1465-2080}, mesh = {*Rhizobium/metabolism ; Cadherins/metabolism ; Green Fluorescent Proteins ; Extracellular Polymeric Substance Matrix/metabolism ; *Rhizobium leguminosarum ; Bacterial Proteins/metabolism ; }, abstract = {Rhizobium adhering proteins or 'Raps' are secreted proteins identified in a very restricted group of rhizobial strains, specifically those belonging to R. leguminosarum and R. etli. The distinctive feature of members of the Rap family is the presence of one or two cadherin-like domains or CHDLs that are also present in numerous extracellular bacterial and archaeal proteins and were proposed to confer carbohydrate binding ability. We have previously made an in-depth characterization of RapA2, a calcium-binding lectin, composed by two CHDLs, involved in biofilm matrix remodelling in R. leguminosarum bv. viciae 3841. In this study, CHDLs derived from RapA2 were analysed in detail, finding significant structural and functional differences despite their considerable sequence similarity. Only the carboxy-terminal CHDL retained properties similar to those displayed by RapA2. Our findings were used to obtain a novel fluorescent probe to study biofilm matrix development by confocal laser scanning microscopy, and also to shed some light on the role of the ubiquitous CHDL domains in bacterial secreted proteins.}, } @article {pmid36748304, year = {2023}, author = {Deng, Y and Fu, Y and Chua, SL and Khoo, BL}, title = {Biofilm Potentiates Cancer-Promoting Effects of Tumor-Associated Macrophages in a 3D Multi-Faceted Tumor Model.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {19}, number = {19}, pages = {e2205904}, doi = {10.1002/smll.202205904}, pmid = {36748304}, issn = {1613-6829}, mesh = {Humans ; *Tumor-Associated Macrophages ; Macrophages ; Immunotherapy/methods ; Immunomodulation ; *Urinary Bladder Neoplasms ; Tumor Microenvironment ; }, abstract = {Components of the tumor microenvironment (TME), such as tumor-associated macrophages (TAMs), influence tumor progression. The specific polarization and phenotypic transition of TAMs in the tumor microenvironment lead to two-pronged impacts that can promote or hinder cancer development and treatment. Here, a novel microfluidic multi-faceted bladder tumor model (TAM[PIEB]) is developed incorporating TAMs and cancer cells to evaluate the impact of bacterial distribution on immunomodulation within the tumor microenvironment in vivo. It is demonstrated for the first time that biofilm-induced inflammatory conditions within tumors promote the transition of macrophages from a pro-inflammatory M1-like to an anti-inflammatory/pro-tumor M2-like state. Consequently, multiple roles and mechanisms by which biofilms promote cancer by inducing pro-tumor phenotypic switch of TAMs are identified, including cancer hallmarks such as reducing susceptibility to apoptosis, enhancing cell viability, and promoting epithelial-mesenchymal transition and metastasis. Furthermore, biofilms formed by extratumoral bacteria can shield tumors from immune attack by TAMs, which can be visualized through various imaging assays in situ. The study sheds light on the underlying mechanism of biofilm-mediated inflammation on tumor progression and provides new insights into combined anti-biofilm therapy and immunotherapy strategies in clinical trials.}, } @article {pmid36747833, year = {2023}, author = {Wang, L and Wong, YC and Correira, JM and Wancura, M and Geiger, CJ and Webster, SS and Butler, BJ and Oâ Toole, GA and Langford, RM and Brown, KA and Dortdivanlioglu, B and Webb, L and Cosgriff-Hernandez, E and Gordon, VD}, title = {Bacterial mechanosensing of surface stiffness promotes signaling and growth leading to biofilm formation by Pseudomonas aeruginosa.}, journal = {bioRxiv : the preprint server for biology}, volume = {}, number = {}, pages = {}, pmid = {36747833}, abstract = {UNLABELLED: The attachment of bacteria onto a surface, consequent signaling, and the accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that the stiffness of a surface may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of and response to surface stiffness are unknown. Furthermore, whether, and how, the surface stiffness impacts biofilm development, after initial accumulation, is not known. We use thin and thick hydrogels to create stiff and soft composite materials, respectively, with the same surface chemistry. Using quantitative microscopy, we find that the accumulation, motility, and growth of the opportunistic human pathogen Pseudomonas aeruginosa respond to surface stiffness, and that these are linked through cyclic-di-GMP signaling that depends on surface stiffness. The mechanical cue stemming from surface stiffness is elucidated using finite-element modeling combined with experiments - adhesion to stiffer surfaces results in greater changes in mechanical stress and strain in the bacterial envelope than does adhesion to softer surfaces with identical surface chemistry. The cell-surface-exposed protein PilY1 acts as a mechanosensor, that upon surface engagement, results in higher cyclic-di-GMP levels, lower motility, and greater accumulation on stiffer surfaces. PilY1 impacts the biofilm lag phase, which is extended for bacteria attaching to stiffer surfaces. This study shows clear evidence that bacteria actively respond to different stiffness of surfaces where they adhere via perceiving varied mechanical stress and strain upon surface engagement.

IMPORTANCE: Bacteria colonize many types of biological and medical surfaces with a large range of stiffnesses. Colonization leads to the formation of biofilms, which cause costly and life-impairing chronic infections. However, whether and how bacteria can sense and respond to the mechanical cue provided by surface stiffness has remained unknown. We find that bacteria do indeed respond to surface stiffness in a way that is both consistent with expectations based on equilibrium continuum mechanics and that quantitatively impacts multiple aspects of early biofilm formation. This is a new understanding for the nascent field of bacterial mechanobiology. Furthermore, this finding suggests the possibility of a new category of approaches to hindering biofilm development by tuning the mechanical properties of biomedical surfaces.}, } @article {pmid36746918, year = {2023}, author = {Lee, JW and Jeong, SY and Kim, TG}, title = {Epifluorescence Microscopy with Image Analysis as a Promising Method for Multispecies Biofilm Quantification.}, journal = {Journal of microbiology and biotechnology}, volume = {33}, number = {3}, pages = {348-355}, pmid = {36746918}, issn = {1738-8872}, mesh = {*Microscopy ; *Biofilms ; Bacteria ; }, abstract = {Epifluorescence microscopy with image analysis was evaluated as a biofilm quantification method (i.e., quantification of surface area colonized by biofilms), in comparison with crystal violet (CV) staining. We performed different experiments to generate multispecies biofilms with natural and artificial bacterial assemblages. First, four species were inoculated daily in 16 different sequences to form biofilms (surface colonization, 0.1%-56.6%). Second, a 9-species assemblage was allowed to form biofilms under 10 acylase treatment episodes (33.8%-55.6%). The two methods comparably measured the quantitative variation in biofilms, exhibiting a strong positive relationship (R[2] ≥ 0.7). Moreover, the two methods exhibited similar levels of variation coefficients. Finally, six synthetic and two natural consortia were allowed to form biofilms for 14 days, and their temporal dynamics were monitored. The two methods were comparable in quantifying four biofilms colonizing ≥18.7% (R[2] ≥ 0.64), but not for the other biofilms colonizing ≤ 3.7% (R[2] ≤ 0.25). In addition, the two methods exhibited comparable coefficients of variation in the four biofilms. Microscopy and CV staining comparably measured the quantitative variation of biofilms, exhibiting a strongly positive relationship, although microscopy cannot appropriately quantify the biofilms below the threshold colonization. Microscopy with image analysis is a promising approach for easily and rapidly estimating absolute quantity of multispecies biofilms.}, } @article {pmid36746768, year = {2023}, author = {Williams, DE and Nesbitt, NM and Muralidharan, S and Hossain, S and Boon, EM}, title = {H-NOX Regulates Biofilm Formation in Agrobacterium Vitis in Response to NO.}, journal = {Biochemistry}, volume = {62}, number = {4}, pages = {912-922}, doi = {10.1021/acs.biochem.2c00639}, pmid = {36746768}, issn = {1520-4995}, support = {K12 GM102778/GM/NIGMS NIH HHS/United States ; }, mesh = {*Bacterial Proteins/chemistry ; Nitric Oxide/metabolism ; Kinetics ; *Escherichia coli Proteins/metabolism ; Biofilms ; Phosphorus-Oxygen Lyases/genetics/metabolism ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Transitions between motile and biofilm lifestyles are highly regulated and fundamental to microbial pathogenesis. H-NOX (heme-nitric oxide/oxygen-binding domain) is a key regulator of bacterial communal behaviors, such as biofilm formation. A predicted bifunctional cyclic di-GMP metabolizing enzyme, composed of diguanylate cyclase and phosphodiesterase (PDE) domains (avi_3097), is annotated downstream of an hnoX gene in Agrobacterium vitis S4. Here, we demonstrate that avH-NOX is a nitric oxide (NO)-binding hemoprotein that binds to and regulates the activity of avi_3097 (avHaCE; H-NOX-associated cyclic di-GMP processing enzyme). Kinetic analysis of avHaCE indicates a ∼four-fold increase in PDE activity in the presence of NO-bound avH-NOX. Biofilm analysis with crystal violet staining reveals that low concentrations of NO reduce biofilm growth in the wild-type A. vitis S4 strain, but the mutant ΔhnoX strain has no NO phenotype, suggesting that H-NOX is responsible for the NO biofilm phenotype in A. vitis. Together, these data indicate that avH-NOX enhances cyclic di-GMP degradation to reduce biofilm formation in response to NO in A. vitis.}, } @article {pmid36744887, year = {2023}, author = {Foote, A and Schutz, K and Zhao, Z and DiGianivittorio, P and Korwin-Mihavics, BR and LiPuma, JJ and Wargo, MJ}, title = {Characterizing Biofilm Interactions between Ralstonia insidiosa and Chryseobacterium gleum.}, journal = {Microbiology spectrum}, volume = {11}, number = {2}, pages = {e0410522}, pmid = {36744887}, issn = {2165-0497}, abstract = {Ralstonia insidiosa and Chryseobacterium gleum are bacterial species commonly found in potable water systems, and these two species contribute to the robustness of biofilm formation in a model six-species community from the International Space Station (ISS) potable water system. Here, we set about characterizing the interaction between these two ISS-derived strains and examining the extent to which this interaction extends to other strains and species in these two genera. The enhanced biofilm formation between the ISS strains of R. insidiosa and C. gleum is robust to starting inoculum and temperature and occurs in some but not all tested growth media, and evidence does not support a soluble mediator or coaggregation mechanism. These findings shed light on the ISS R. insidiosa and C. gleum interaction, though such enhancement is not common between these species based on our examination of other R. insidiosa and C. gleum strains, as well as other species of Ralstonia and Chryseobacterium. Thus, while the findings presented here increase our understanding of the ISS potable water model system, not all our findings are broadly extrapolatable to strains found outside of the ISS. IMPORTANCE Biofilms present in drinking water systems and terminal fixtures are important for human health, pipe corrosion, and water taste. Here, we examine the enhanced biofilm of cocultures for two very common bacteria from potable water systems: Ralstonia insidiosa and Chryseobacterium gleum. While strains originally isolated on the International Space Station show enhanced dual-species biofilm formation, terrestrial strains do not show the same interaction properties. This study contributes to our understanding of these two species in both dual-culture and monoculture biofilm formation.}, } @article {pmid36744530, year = {2023}, author = {Boddapati, S and Gummadi, SN}, title = {Production and application of purified mutanase from novel Cellulosimicrobium funkei SNG1 in the in vitro biofilm degradation.}, journal = {Biotechnology and applied biochemistry}, volume = {70}, number = {3}, pages = {1371-1383}, doi = {10.1002/bab.2446}, pmid = {36744530}, issn = {1470-8744}, support = {SR/WOS-A/LS-479/2017//Department of Science and Technology-WOS A/ ; }, mesh = {*Glycoside Hydrolases/chemistry ; *Biofilms ; Glucans/chemistry/metabolism/pharmacology ; Hydrogen-Ion Concentration ; Temperature ; }, abstract = {Mutanase (α-1,3-glucanase) is an inducible extracellular enzyme with potential medical applications in dentistry. A novel Cellulosimicrobium funkei strain SNG1 producing mutanase enzyme using α-1,3-glucans was isolated, and the enzyme was optimized for increased productivity using the one-factor-at-a-time approach. Maximum growth and enzyme-specific activity (2.12 ± 0.4 U/mg) were attained in a production medium with pH 7.0 and 1% α-1,3-glucans as carbon source, incubated at 37°C for 30 h. The result showed a five-fold increase in activity compared to unoptimized conditions (0.40 U/mg). The enzyme was purified by gel-filtration chromatography, and recovered with a yield of 29.03% and a specific activity increase of 10.9-fold. The molecular mass of the monomeric enzyme is 137 kDa. The pH and temperature optima are 6.0 and 45°C with Km of 1.28 ± 0.11 mg for α-1,3-glucans. The enzyme activity was stimulated by adding Co[2+] , Ca[2+] , Cu[2+] , and was entirely inhibited by Hg[2+] . On 2-h incubation, the purified enzyme effectively degraded in vitro film with an 82.68% degradation rate and a saccharification yield of 30%.}, } @article {pmid36744091, year = {2023}, author = {Lan, S and Chen, X and Yin, C and Xie, S and Wang, S and Deng, R and Shen, Z}, title = {Antibacterial and anti-biofilm activities of Disaspidin BB against Staphylococcus epidermidis.}, journal = {Frontiers in microbiology}, volume = {14}, number = {}, pages = {999449}, pmid = {36744091}, issn = {1664-302X}, abstract = {INTRODUCTION: Staphylococcus epidermidis infections are an important concern in worldwide, especially when associated with biofilms, and resistance of this agent to many drugs makes the situation even worse. We investigated the inhibitory effect of Disaspidin BB obtained from plant extracts and purifications on clinical S. epidermidis strains and their biofilms, and preliminarily investigated its mechanism of of its anti-biofilm activity.

METHODS AND RESULTS: The broth dilution method was used to determine the minimum inhibitory concentrations (MIC) of Disaspidin BB on 11 clinical S. epidermidis strains (MIC value of 0.63 ~ 2.5 μg/ml). SEP-05 was found to be erythromycin-resistant (MIC value>8 μg/ml) and Disaspidin BB sensitive with an MIC value of 0.63 μg/ml. The time-kill curve assay indicated that the antibacterial activity of Disaspidin BB against SEP-05 with concentration dependence. The metabolic activity and total biomass of the drug-treated SEP-05 biofilm in each stage were significantly inhibited by the crystalline violet and XTT assay, and the scavenging effect of Disaspidin BB on SEP-05 biofilm was also confirmed by SEM observation. The results of real-time quantitative PCR showed that subinhibitory concentrations Disaspidin BB can inhibit biofilm formation by affecting the expression level of key genes (aap, atlE, icaA, luxS, recA) in SEP-05 biofilm formation. In addition, the content of polysaccharides, proteins and extracellular DNA in biofilm matrix after the intervention of Disaspidin BB was significantly reduced, and it was tentatively determined that the ability of SEP-05 biofilm formation and its stability were thus disturbed.

DISCUSSION: The results show that Disaspidin BB has promising antibacterial effect on erythromycin-resistant S. epidermidis and significant scavenging effect on its biofilm, which provides a theoretical basis for the further development of BB as a new drug for the treatment of skin infections caused by S. epidermidis.}, } @article {pmid36741766, year = {2023}, author = {Tang, Z and Zhang, H and Xiong, J and Li, Y and Luo, W}, title = {Enhanced iturin a production in a two-compartment biofilm reactor by Bacillus velezensis ND.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1102786}, pmid = {36741766}, issn = {2296-4185}, abstract = {In this study, a two-compartment biofilm reactor was designed for iturin A production. The biofilm reactor consists of a stirred-tank fermentor containing exclusively suspended cells and a packing column where the biofilm is attached. Polyester fiber with sphere shape and rough surfaces was chosen as the carrier of biofilm in packing column. Batch, fed-batch, and repeated-batch fermentation using Bacillus velezensis ND in the biofilm reactor were studied. Compared to conventional suspended cell fermentations, the productivity of iturin A in batch and fed-batch biofilm fermentation were increased by 66.7% and 63.3%, respectively. Maximum itutin A concentration of 6.8 ± 0.1 g/L and productivity of 46.9 ± 0.2 mg/L/h were obtained in fed-batch biofilm fermentation. Repeated-batch fermentation showed high stability, with almost same profile as batch fermentation. After a step-wise temperature control strategy was introduced in the biofilm reactor, productivity of iturin A was increased by 131.9% compared to suspended cell reactor. This superior performance of biofilm reactor confirms that it has great potential in industrial production of iturin A.}, } @article {pmid36741763, year = {2023}, author = {Winkelhorst, M and Cabau-Peinado, O and Straathof, AJJ and Jourdin, L}, title = {Biomass-specific rates as key performance indicators: A nitrogen balancing method for biofilm-based electrochemical conversion.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {11}, number = {}, pages = {1096086}, pmid = {36741763}, issn = {2296-4185}, abstract = {Microbial electrochemical technologies (METs) employ microorganisms utilizing solid-state electrodes as either electron sink or electron source, such as in microbial electrosynthesis (MES). METs reaction rate is traditionally normalized to the electrode dimensions or to the electrolyte volume, but should also be normalized to biomass amount present in the system at any given time. In biofilm-based systems, a major challenge is to determine the biomass amount in a non-destructive manner, especially in systems operated in continuous mode and using 3D electrodes. We developed a simple method using a nitrogen balance and optical density to determine the amount of microorganisms in biofilm and in suspension at any given time. For four MES reactors converting CO2 to carboxylates, >99% of the biomass was present as biofilm after 69 days of reactor operation. After a lag phase, the biomass-specific growth rate had increased to 0.12-0.16 days[-1]. After 100 days of operation, growth became insignificant. Biomass-specific production rates of carboxylates varied between 0.08-0.37 molC molX [-1]d[-1]. Using biomass-specific rates, one can more effectively assess the performance of MES, identify its limitations, and compare it to other fermentation technologies.}, } @article {pmid36741169, year = {2023}, author = {Lu, X and Wang, G and Xie, Y and Tang, W and Liu, B and Zhang, J}, title = {Efflux pump inhibitor combined with ofloxacin decreases MRSA biofilm formation by regulating the gene expression of NorA and quorum sensing.}, journal = {RSC advances}, volume = {13}, number = {4}, pages = {2707-2717}, pmid = {36741169}, issn = {2046-2069}, abstract = {Carbonyl cyanide p-nitrophenylhydrazone (2e) displayed a lone or synergistic efficacy against MRSA (RSC Adv., 2020, 10, 17854). In this work, the synergistic mechanism of 2e with ofloxacin was studied. MRSA2858 had potential for biofilm formation, and the value of MBEC of 2e alone was 0.78-1.56 μM, while that of 2e + ofloxacin was 0.39-0.78 μM. 2e combined with ofloxacin showed a synergistic anti-biofilm effect against MRSA. Efflux pump inhibitor 2e can better bind to NorA protein. After MRSA2858 was treated with 2e of 1/2MIC (0.78 μM) and ofloxacin of 1/8MIC (0.097 μM), the transcript levels of efflux genes (norA) and quorum-sensing (QS) regulatory genes (agrA, sarA, icaA, hla) were substantially down-regulated, and alpha-hemolysin (Hla) was inhibited by 99.15%. 2e combined with ofloxacin was more effective than 2e alone in reducing bacterial load in vivo. All in all, efflux pump inhibitor 2e enhanced the bactericidal activities of antibiotics through regulating the gene expression of NorA and QS system.}, } @article {pmid36739193, year = {2023}, author = {Taira, H and Yaga, M and Nakasone, S and Nishida, K and Yamashiro, T}, title = {Significant removal of bacterial biofilm induced by multiple-Short ranges of electric interventions.}, journal = {Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jos.2022.12.017}, pmid = {36739193}, issn = {1436-2023}, abstract = {BACKGROUND: Biofilm-related infections are serious problems in the Orthopedics field, and Staphylococcus aureus are the most popular causative agents of bacterial infections associated with arthroplasty. Several studies demonstrated a synergistic effect of the electric intervention (EI) and the antibiotic administration in killing bacteria in biofilm; however, a constant, long-time EI was needed. In the present study, the effective removal of biofilm formed with S. aureus on a titanium ring by multiple times of one minute-EI was observed and described.

METHODS: A methicillin-sensitive S. aureus clinical isolate was used to form biofilm on a titanium ring. After applying a series of EI with various combinations of the frequencies and timings, the amount and principal components of biofilms were assessed with crystal violet staining, live bacterial cell count, and fluorescence staining with confocal laser scanning microscopy.

RESULTS: More than 60% biofilm removal was observed in the 2-time EI applied at 24 (1) and 72 (3) h (days) post bacterial exposure (PBE) and in the 3-time EI at 0 (0), 24 (1), and 72 (3) h (days) PBE, or at 24 (1), 48 (2), and 72 (3) h (days) PBE. The live bacterial cell numbers, the proportion of live and dead cells, and the amount of extracellular polysaccharide substances (EPS) of biofilm were similar with or without EI. It was assumed that an excess amount of the biofilm removal shown in the several EI was not attributed to the effect of the electrolysis.

CONCLUSIONS: The effective removal of biofilm was observed when multiple times 1 min EI was applied without any changes in the proportion of live and dead bacteria or the amount of EPS. The mechanisms to explain extra biofilm removal remain to be elucidated.}, } @article {pmid36738904, year = {2023}, author = {Park, GH and Lee, SY and Lee, JB and Chang, BS and Lee, JK and Um, HS}, title = {Effect of photodynamic therapy according to differences in photosensitizers on Staphylococcus aureus biofilm on titanium.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {41}, number = {}, pages = {103317}, doi = {10.1016/j.pdpdt.2023.103317}, pmid = {36738904}, issn = {1873-1597}, mesh = {Humans ; Photosensitizing Agents/pharmacology ; Staphylococcus aureus ; *Photochemotherapy/methods ; Titanium/pharmacology ; Biofilms ; *Staphylococcal Infections/drug therapy ; Lasers, Semiconductor ; Tolonium Chloride/pharmacology ; }, abstract = {PURPOSE: This study aimed to evaluate the antimicrobial effect of photodynamic therapy (PDT) against Staphylococcus aureus biofilm on a titanium surface and to compare the differences in the effect of PDT using toluidine blue O (TBO) and methylene blue (MB) as a photosensitizer.

METHODS: The bacterial strain S. aureus ATCC 25,923 was used. Sandblasted and acid-etched (SLA) disks were divided into the following six groups: phosphate buffer saline (PBS), TBO, MB, PBS with laser (PBS + L), TBO with laser (TBO + L), and MB with laser (MB + L). The laser group samples were irradiated by a cold diode laser for 60 s. After treatment, the number of surviving bacteria was calculated by counting the colony-forming units (CFUs) and confocal laser scanning microscopy (CLSM) was applied to observe the bacteria on the disk surface.

RESULTS: The TBO + L and MB + L groups showed significantly lower CFU/ml than the other groups (p < 0.01). The TBO + L group showed significantly lower CFU/ml than the MB + L group (p = 0.032). There was no significant difference between the PBS, TBO, MB, and PBS + L groups. Within the limitations of this in vitro study, PDT with TBO and MB can effectively reduce S. aureus biofilm on SLA titanium surfaces. TBO is more effective than MB as a photosensitizer. PDT with TBO may be applied to the treatment of peri‑implant disease in the future.}, } @article {pmid36738701, year = {2023}, author = {Balasubramanian, N and Pounpandi, P and Varatharaju, G and Shanmugaiah, V and Balakrishnan, K and Thirunarayan, MA}, title = {Distribution of virulence genes and biofilm characterization of human isolates of Streptococcus agalactiae: A pilot study.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {223}, number = {}, pages = {113151}, doi = {10.1016/j.colsurfb.2023.113151}, pmid = {36738701}, issn = {1873-4367}, mesh = {Humans ; Male ; Female ; *Streptococcus agalactiae ; Virulence ; Pilot Projects ; Virulence Factors/genetics ; *Streptococcal Infections ; Anti-Bacterial Agents ; }, abstract = {This study included 21 newly isolated clinical samples of Streptococcus agalactiae (Group B Streptococcus) screened in patients (six male, fifteen female) from various states of India with different infections (urinary tract infections, blood, pus and eye infections). All isolates were identified as Group B Streptococcus (GBS) using hemolytic properties, serogrouping and MALDI-TOF-MS analysis. Six virulence genes, cfb (100%), cylE (90.4%), lmp (85.7%), bca (71.4%), rib (38%) and bac (4.7%) were detected via polymerase chain reaction (PCR). Distribution studies of these six genes revealed five isolates containing five virulence genes (23.8%), followed by ten isolates containing four virulence genes (47.6%). The twenty GBS isolates selected on the glass surface included non-biofilm producers (n = 6, 30%), weak (n = 11, 55%) and moderate biofilm producers (n = 3, 15%). On the polystyrene surface, weak (n = 4, 20%), moderate (n = 2, 10%) and strong (n = 14, 70%) biofilm producers were detected. Live-dead cell staining revealed that more viable cells accumulated in the S. ag 7420 isolate than in the AH1 isolate. Scanning electron microscope (SEM) biofilm analysis showed S. ag AH1 cells appeared as chain-like structures, whereas the S. ag 7420 isolate biofilm cells appeared as fork-like structures on the glass surface. Biofilm elements were analyzed using Energy Dispersive X-Ray Analysis (EDAX) for both isolates and 13 elements with different orders of composition were found. Thus, virulence gene detection, distribution and biofilm formation by these new clinical isolates suggested the virulent nature of these pathogens, which might cause different levels of disease severity in humans.}, } @article {pmid36737464, year = {2023}, author = {Doherty, C and Byrne, CV and Baqader, S and El-Chami, C and McBain, AJ and Thomason, HA}, title = {Anti-biofilm effects and healing promotion by silver oxynitrate-based dressings.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {2014}, pmid = {36737464}, issn = {2045-2322}, mesh = {Animals ; Mice ; *Staphylococcus aureus ; Silver/pharmacology/chemistry ; Edetic Acid/pharmacology ; Bandages ; Benzethonium/pharmacology ; Biofilms ; *Wound Infection/microbiology ; }, abstract = {Microbial growth within a wound often manifests as biofilms, which can prevent healing and is difficult to eradicate. Novel silver dressings claim to combat wound infection, but anti-biofilm efficacy and effects on healing independent of infection are often unclear. Using in vitro and in vivo S. aureus and P. aeruginosa biofilm models, we report the efficacy of a dressing which produces Ag[1+] ions; an Ag[1+] dressing containing ethylenediaminetetraacetic acid and benzethonium chloride (Ag[1+]/EDTA/BC), and a dressing containing silver oxynitrate (Ag Oxysalts) which produces Ag[1+], Ag[2+] and Ag[3+] ions, against wound biofilms, and their effects on healing. Ag[1+] dressings had minimal effect on in vitro and murine (C57BL/6j) wound biofilms. In contrast, Ag Oxysalts and Ag[1+]/EDTA/BC dressings significantly reduced viable bacteria within in vitro biofilms and demonstrated a visible reduction in bacteria and EPS components within murine wound biofilms. The dressings had different effects on the healing of biofilm-infected and uninfected wounds, with Ag Oxysalts dressings having a greater beneficial effect on re-epithelialisation, wound size and inflammation than the control treatment and the other silver dressings. The different physicochemical properties of the silver dressings result in varied effects on wound biofilms and healing which should be considered when selecting dressings to treat biofilm-infected wounds.}, } @article {pmid36736398, year = {2023}, author = {Gabriele, F and Ranaldi, R and Bruno, L and Casieri, C and Rugnini, L and Spreti, N}, title = {Biodeterioration of stone monuments: Studies on the influence of bioreceptivity on cyanobacterial biofilm growth and on the biocidal efficacy of essential oils in natural hydrogel.}, journal = {The Science of the total environment}, volume = {870}, number = {}, pages = {161901}, doi = {10.1016/j.scitotenv.2023.161901}, pmid = {36736398}, issn = {1879-1026}, mesh = {*Oils, Volatile ; Thymol ; Hydrogels ; Biofilms ; *Cyanobacteria ; *Disinfectants/pharmacology ; }, abstract = {An important field of research is devoted to the development of innovative, sustainable, and safe methodologies to counteract biodeterioration of stone monuments due to the growth of microbial communities. However, besides the biocide's efficacy, it is crucial to consider the features of substrates on which biocides must be applied, to define the so-called bioreceptivity of the lithic faces. In this research five different lithotypes, namely Lecce stone, Travertine, Peperino, Serena stone, and Granite, have been used as substrates for the growth of cyanobacterial biofilms. Open porosity, hygroscopic properties, and roughness parameters have been investigated for each lithotype and correlated to the photosynthetic yields of the biofilms colonizing the different stones to propose an easy method to estimate stone bioreceptivity. Different levels of coverage of the stone surfaces have been accomplished in relation to the typology of lithotypes. To develop innovative restoration methodologies against biodeterioration of stone monuments, a hydrogel-biocide system has been optimized by using a polysaccharide dispersion as a matrix where to embed T. vulgaris essential oil (at 0.25 % or 0.1 %) or its main component thymol (at 0.18 % or 0.07 %). The efficacy and the effect of the innovative biocide have been evaluated combining microscopy, photosynthetic measurements, and colorimetric analyses and both the biocides (with T. vulgaris EO or thymol) showed to be highly effective against the cyanobacterial biofilms for at least six months from the treatment without inducing any significant alteration to the lithic surfaces. The efficacy of thymol alone allows to treat colonized surfaces with a single active ingredient, or at least a mixture thereof, much cheaper and reproducible. The results obtained in this work pave the way to develop a sustainable cleaning protocol to counteract the biodeterioration of stone monuments or historic buildings induced by the presence of phototrophic biofilms that endangered their conservation.}, } @article {pmid36735239, year = {2023}, author = {Ćirković, I and Pejović, A and Jovićević, M and Brkić, S and Djukić, S and Božić, DD}, title = {Staphylococcal biofilm on wedding rings worn by laboratory workers.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {70}, number = {1}, pages = {73-78}, doi = {10.1556/030.2023.01919}, pmid = {36735239}, issn = {1588-2640}, mesh = {Humans ; Staphylococcus/genetics ; Anti-Bacterial Agents ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics ; Biofilms ; Microbial Sensitivity Tests ; *Methicillin-Resistant Staphylococcus aureus ; }, abstract = {Hands of healthcare workers play essential role in the spreading of antimicrobial-resistant microorganisms in and out of the healthcare settings. Less is known about the role of laboratory workers (LWs). The aim of our study was to evaluate the presence of biofilm-forming staphylococci on the surface of jewelry rings of LWs and their antimicrobial susceptibility pattern.A total of 79 LWs from eight different microbiology laboratories that process and analyze specimens from the tertiary care hospitals in Belgrade, Serbia participated in the study. The study was reviewed and approved by the institutional review boards at hospitals. Samples were taken after hand washing. Bacteria on LWs wedding rings were detected with the rolling method, and further analyzed in order to determine the number of colony forming unit (CFU) per ring, species of bacteria and their antimicrobial susceptibility pattern, methicillin resistance and biofilm-producing capacity in vitro.Staphylococci were recovered from 60.8% of wedding rings. All strains produced biofilm (25% weak, 56.2% moderate and 18.8% large amount), with significant difference between species (P < 0.001). Staphylococcus aureus and Staphylococcus epidermidis formed the largest amount of biofilm and had the largest number of CFU per ring. Staphylococci were most commonly resistant to penicillin (66.7%), tetracycline (50.0%), and erythromycin (45.8%); 41.7% of isolates was multidrug resistant and mecA gene was detected in five strains. All strains were susceptible to linezolid, vancomycin, teicoplanin and tigecycline.Staphylococci colonize LWs wedding rings, form biofilm on it, have multidrug resistant phenotype and/or carry mecA gene, representing a significant reservoir for the spreading of microorganisms and resistance. As far as we know, our study is the first that address this topic in laboratory workers.}, } @article {pmid36732890, year = {2023}, author = {Maric, T and Løvind, A and Zhang, Z and Geng, J and Boisen, A}, title = {Near-Infrared Light-Driven Mesoporous SiO2 /Au Nanomotors for Eradication of Pseudomonas aeruginosa Biofilm.}, journal = {Advanced healthcare materials}, volume = {12}, number = {13}, pages = {e2203018}, doi = {10.1002/adhm.202203018}, pmid = {36732890}, issn = {2192-2659}, support = {DNRF122//Danish National Research Foundation/ ; 9301//Villum Fonden/ ; NNF17OC0026910//Intelligent Drug Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN) and the Novo Nordisk Foundation/ ; CF19-0379//Carlsberg Foundation/ ; }, mesh = {Humans ; *Pseudomonas aeruginosa ; Silicon Dioxide ; *Nanoparticles ; Infrared Rays ; Biofilms ; }, abstract = {Bacterial biofilms are linked to several diseases and cause resistant and chronic infections in immune-compromised patients. Nanomotors comprise a new field of research showing a great promise within biomedicine but pose challenges in terms of biocompatibility. Nanomotors propelled by thermophoresis could overcome this challenge, as they leave no waste product during propulsion. In this study, mesoporous-silica nanoparticles are coated with a thin layer of gold to make nanomotors, which can be driven by near-infrared (NIR) light irradiation. The prepared mesoporous SiO2 -Au nanomotors exhibit efficient self-propulsion when exposed to NIR irradiation, they penetrate deep through a biofilm matrix, and disperse the biofilm in situ due to the photothermal effect on the Au part of the nanomotors. The velocities of such nanomotors are investigated at different wavelengths and laser powers. Furthermore, the study examines the ability of these nanomotors to eradicate Pseudomonas aeruginosa (P. aeruginosa) biofilm under NIR light irradiation. The conducted study shows that the nanomotor's velocity increases with increasing laser power. The mesoporous SiO2 /Au nanomotors show excellent capabilities to eradicate P. aeruginosa biofilms even under short (30 s-3 min) irradiation time. This study shows great promise for overcoming the challenges related to bacterial biofilm eradication.}, } @article {pmid36732330, year = {2023}, author = {Razvi, E and Whitfield, GB and Reichhardt, C and Dreifus, JE and Willis, AR and Gluscencova, OB and Gloag, ES and Awad, TS and Rich, JD and da Silva, DP and Bond, W and Le Mauff, F and Sheppard, DC and Hatton, BD and Stoodley, P and Reinke, AW and Boulianne, GL and Wozniak, DJ and Harrison, JJ and Parsek, MR and Howell, PL}, title = {Glycoside hydrolase processing of the Pel polysaccharide alters biofilm biomechanics and Pseudomonas aeruginosa virulence.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {7}, pmid = {36732330}, issn = {2055-5008}, support = {K99 GM134121/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Biomechanical Phenomena ; Drosophila melanogaster/microbiology ; *Glycoside Hydrolases/genetics ; *Pseudomonas aeruginosa/physiology ; Virulence ; Caenorhabditis elegans/microbiology ; *Polysaccharides, Bacterial ; }, abstract = {Pel exopolysaccharide biosynthetic loci are phylogenetically widespread biofilm matrix determinants in bacteria. In Pseudomonas aeruginosa, Pel is crucial for cell-to-cell interactions and reducing susceptibility to antibiotic and mucolytic treatments. While genes encoding glycoside hydrolases have long been linked to biofilm exopolysaccharide biosynthesis, their physiological role in biofilm development is unclear. Here we demonstrate that the glycoside hydrolase activity of P. aeruginosa PelA decreases adherent biofilm biomass and is responsible for generating the low molecular weight secreted form of the Pel exopolysaccharide. We show that the generation of secreted Pel contributes to the biomechanical properties of the biofilm and decreases the virulence of P. aeruginosa in Caenorhabditis elegans and Drosophila melanogaster. Our results reveal that glycoside hydrolases found in exopolysaccharide biosynthetic systems can help shape the soft matter attributes of a biofilm and propose that secreted matrix components be referred to as matrix associated to better reflect their influence.}, } @article {pmid36731617, year = {2023}, author = {Wang, Q and Pan, Y and Chu, G and Lu, S and Zhang, Z and Zhao, Y and Jin, C and Gao, M}, title = {Impact of aerobic/anoxic alternation number on performance, microbial community and functional genes of sequencing batch biofilm reactor treating mariculture wastewater.}, journal = {Bioresource technology}, volume = {372}, number = {}, pages = {128699}, doi = {10.1016/j.biortech.2023.128699}, pmid = {36731617}, issn = {1873-2976}, mesh = {*Wastewater ; *Waste Disposal, Fluid/methods ; Bioreactors ; Nitrification ; Microbial Consortia ; Biofilms ; Nitrogen/metabolism ; Denitrification ; }, abstract = {The performance, microbial community and functional genes of a sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater under different aerobic/anoxic alternation number. The removal efficiency of chemical oxygen demand (COD) and NH4[+]-N kept at 95.66 ± 1.83 % and 90.28 ± 2.42 % under aerobic/anoxic alternation number between 1 and 4. The total nitrogen (TN) removal efficiency gradually decreased from 94.45 ± 1.12 % to 83.06 ± 1.25 % with the increase of aerobic/anoxic alternative number from 1 to 4. The nitrification rates and their corresponding enzymatic activities increased slightly with the increase of aerobic/anoxic alternation number, whereas the denitrifying process had the contrary results. The variation of aerobic/anoxic alternation number obviously affected the microbial diversity and abundance. The microbial network structure and keystone taxa were different under different aerobic/anoxic alternation number. The functional genes abundance for the denitrification pathway decreased with the increase of aerobic/anoxic alternation number.}, } @article {pmid36731122, year = {2023}, author = {Dzofou Ngoumelah, D and Kuchenbuch, A and Harnisch, F and Kretzschmar, J}, title = {Combining Geobacter spp. Dominated Biofilms and Anaerobic Digestion Effluents─The Effect of Effluent Composition and Electrode Potential on Biofilm Activity and Stability.}, journal = {Environmental science & technology}, volume = {57}, number = {6}, pages = {2584-2594}, doi = {10.1021/acs.est.2c07574}, pmid = {36731122}, issn = {1520-5851}, mesh = {*Bioelectric Energy Sources ; *Geobacter ; Anaerobiosis ; Biofilms ; Electrodes ; }, abstract = {The combination of anaerobic digestion (AD) and microbial electrochemical technologies (METs) offers different opportunities to increase the efficiency and sustainability of AD processes. However, methanogenic archaea and/or particles may partially hinder combining MET and AD processes. Furthermore, it is unclear if the applied anode potential affects the activity and efficiency of electroactive microorganisms in AD-MET combinations as it is described for more controlled experimental conditions. In this study, we confirm that 6-week-old Geobacter spp. dominated biofilms are by far more active and stable in AD-effluents than 3-week-old Geobacter spp. dominated biofilms. Furthermore, we show that the biofilms are twice as active at -0.2 V compared to 0.4 V, even under challenging conditions occurring in AD-MET systems. Paired-end amplicon sequencing at the DNA level using 16S-rRNA and mcrA gene shows that hydrogenotrophic methanogens incorporate into biofilms immersed in AD-effluent without any negative effect on biofilm stability and electrochemical activity.}, } @article {pmid36730195, year = {2023}, author = {Platt, TG}, title = {Community outcomes depend on cooperative biofilm structure.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {6}, pages = {e2221624120}, pmid = {36730195}, issn = {1091-6490}, support = {P20 GM130448/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; *Bacteria ; Bacterial Physiological Phenomena ; }, } @article {pmid36724854, year = {2023}, author = {Zhou, W and Niu, D and Gao, S and Zhong, Q and Liu, C and Liao, X and Cao, X and Zhang, Z and Zhang, Y and Shen, H}, title = {Prevalence, biofilm formation, and mass spectrometric characterization of linezolid-resistant Staphylococcus capitis isolated from a tertiary hospital in China.}, journal = {Journal of global antimicrobial resistance}, volume = {33}, number = {}, pages = {155-163}, doi = {10.1016/j.jgar.2023.01.005}, pmid = {36724854}, issn = {2213-7173}, mesh = {Linezolid/pharmacology ; *Staphylococcus capitis/genetics ; Anti-Bacterial Agents/pharmacology ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Tertiary Care Centers ; RNA, Ribosomal, 23S/genetics ; Prevalence ; Retrospective Studies ; Staphylococcus/genetics ; Biofilms ; }, abstract = {OBJECTIVES: Linezolid-resistant Staphylococcus capitis (LRSC) has become a new challenge for clinical anti-infective therapy. The present study aimed to investigate the trends of LRSC prevalence in a tertiary hospital of China 2017-2020. The resistance mechanisms, virulence genes, biofilm formation, and mass spectrometric characteristics of LRSC isolates were also analysed.

METHODS: This study retrospectively analysed the antibiotic resistance trends of coagulase negative staphylococci (CoNS) isolated from clinical samples collected between 2017-2020. Antimicrobial resistance profiles were tested by micro-broth dilution and the E-test method. Antimicrobial resistance genes and virulence genes were detected by polymerase chain reaction, and dru-typing sequences were obtained by Sanger sequencing. Crystal violet staining in 96-well plates was used to detect biofilm formation ability. Mass spectrometric characterization of LRSC was analysed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled with ClinProTools.

RESULTS: The linezolid resistance rate in 3575 CoNS clinical strains was 1.6%, wherein the great majority of was LRSC (91.1%, n = 51/56), with a resistant rate of 15.5% (n = 51/328) in all S. capitis isolates. In this study, 48 out of the 51 LRSC strains and 54 of 277 linezolid-susceptible S. capitis (LSSC) strains were enrolled. G2576T, C2104T, T2130A, C2163T, and T2319C mutations in the 23S rRNA V region and acquisition of cfr were the main linezolid resistant mechanisms in LRSC. The biofilm-forming ability of LRSC was more potent than LSSC, with a higher detection rate of bap (P < 0.05). Eleven mass spectrometric peaks of interest were identified by using MALDI-TOF MS and ClinProTools, which were differently distributed between LRSC and LSSC strains, with the area under the receiver operating characteristic curve of more than 0.8, especially for 5465.37 m/z.

CONCLUSIONS: Linezolid resistance was mediated by mutations in the 23S rRNA V region and presence of the cfr gene in LRSC strains. LRSC strains have stronger biofilm-forming ability than LSSC strains, which maybe associated with the adhesion-related gene of bap. Further, linezolid-resistant and linezolid-susceptible S. capitis could be rapidly identified with mass spectrometric characterization. To the best of our knowledge, this study is the first to document the biofilm formation ability of LRSC and the potential usefulness of MALDI-TOF MS for the discrimination of LRSC and LSSC.}, } @article {pmid36723506, year = {2023}, author = {Fathi-Hafshejani, P and Tinker, HB and Freel, K and Mahjouri-Samani, M and Hasim, S}, title = {Effects of TiS2 on Inhibiting Candida albicans Biofilm Formation and Its Compatibility with Human Gingival Fibroblasts in Titanium Implants.}, journal = {ACS applied bio materials}, volume = {6}, number = {2}, pages = {436-444}, doi = {10.1021/acsabm.2c00707}, pmid = {36723506}, issn = {2576-6422}, mesh = {Humans ; Biofilms ; *Candida albicans ; Fibroblasts ; *Titanium/pharmacology/chemistry ; }, abstract = {Titanium is widely used in medical devices, such as dental and orthopedic implants, due to its excellent mechanical properties, low toxicity, and biocompatibility. However, the titanium surface has the risk of microbial biofilm formation, which results in infections from species such as Candida albicans (C. albicans). This kind of biofilm prevents antifungal therapy and complicates the treatment of infectious diseases associated with implanted devices. It is critical to developing a feasible surface to decrease microbial growth while not interfering with the growth of the host cells. This study reports the influence of titanium surface modification to titanium disulfide (TiS2) on inhibiting C. albicans biofilm formation while allowing the attachment of human gingival fibroblasts (HGFs) on their surface. The surface of titanium parts is directly converted to structured titanium and TiS2 using direct laser processing and crystal growth methods. C. albicans adhesion and colonization are then investigated on these surfaces by the colony counting assay and reactive oxygen species (ROS) assay, using 2',7'-dichlorofluorescin diacetate (DCFH-DA) and microscopy images. Also, the viability and adhesion of HGFs on these surfaces are investigated to show their adhesion and biocompatibility. Titanium samples with the TiS2 surface show both C. albicans biofilm inhibition and HGF attachment. This study provides insight into designing and manufacturing titanium biomedical implants.}, } @article {pmid36722674, year = {2023}, author = {Kraft, L and Ribeiro, VST and Petroski, LP and Herai, RH and Peronni, KC and Figueiredo, DLA and Motta, FA and Tuon, FF}, title = {Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil.}, journal = {Revista do Instituto de Medicina Tropical de Sao Paulo}, volume = {65}, number = {}, pages = {e12}, pmid = {36722674}, issn = {1678-9946}, mesh = {Child ; Male ; Humans ; *Saccharomyces cerevisiae ; *Antifungal Agents/pharmacology ; Amphotericin B ; Brazil ; Biofilms ; }, abstract = {Rare emerging pathogens such as Saprochaete clavata are associated with invasive fungal diseases, high morbidity, mortality, rapidly fatal infections, and outbreaks. However, little is known about S. clavata infections, epidemiology, risk factors, treatment, biofilms, and disease outcomes. The objective of this study was to describe a new case of severe S. clavata infection in a patient diagnosed at a referral children's hospital in Brazil, including antifungal minimal inhibitory concentration, S. clavata biofilm characterization, and molecular characterization. The S. clavata isolated from an immunocompromised 11-year-old male patient was characterized using MALDI-TOF, Gram staining, scanning electron microscopy (SEM), and next generation sequencing (NGS) of genomic DNA. Biofilm production was also evaluated in parallel with determining minimal inhibitory concentration (MIC) and biofilm sensitivity to antifungal treatment. We observed small to medium, whitish, farinose, dry, filamentous margin colonies, yeast-like cells with bacillary features, and biofilm formation. The MALDI-TOF system yielded a score of ≥ 2,000, while NGS confirmed S. clavata presence at the nucleotide level. The MIC values (in mg L-1) for tested drugs were as follows: fluconazole = 2, voriconazole ≤ 2, caspofungin ≥ 8, micafungin = 2, amphotericin B = 4, flucytosine ≤ 1, and anidulafungin = 1. Amphotericin B can be active against S. clavata biofilm and the fungus can be susceptible to new azoles. These findings were helpful for understanding the development of novel treatments for S. clavata-induced disease, including combined therapy for biofilm-associated infections.}, } @article {pmid36721500, year = {2022}, author = {Rezania, N and Rahmati, P and Noorbakhsh, F and Farhadyar, N and Lotfali, E}, title = {Investigation the effects of silver nanoparticles and gold nanoparticles on expression of bap and csu genes in biofilm formation of Acinetobacter baumannii.}, journal = {Iranian journal of microbiology}, volume = {14}, number = {4}, pages = {510-517}, pmid = {36721500}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Acinetobacter baumannii is one of the main pathogens of the hospital and causes various infections. csu A/BABCDE involved in the initial surface attachment during biofilm formation and bap gene produces specific proteins at the cell surface that play a direct role in formation of biofilm and the infectivity of this bacterium. The aim of this study was to investigate the effect of silver nanoparticles and gold nanoparticles on the expression of bap and csu genes in the Acinetobacter baumannii biofilm formation.

MATERIALS AND METHODS: The susceptibility test was performed to determine the MIC of silver nanoparticles, gold nanoparticles and gold-vancomycin nanoparticles performed by broth dilution method on A. baumannii strains. The ability of biofilms formation in strains treated by MIC of silver nanoparticles and gold-vancomycin nanoparticles were evaluated by microtiter plate method and A. baumannii ATCC19606 used as control. Expression of the csu and bap genes were determinded by measuring the cognate mRNA level by real-time PCR.

RESULTS: In present study, gold nanoparticles could not prevent the growth and biofilm formation of A. baumannii strains. The MIC concentration of silver nanoparticles and vancomycin- gold nanoparticles were 6.25 μg/ml and 0.625 μg/ml respectively and MBC concenteration of nanoparticles for 70% of strain was 12.5 μg/ml and 1.25 μg/ml respectively. Real-time PCR and data analysis, determined that the expression of bap, csuC and csuE genes in A. baumannii strains treated with MIC concentration (6.25 μg/ml) of silver nanoparticles decreased compared to control groups. Also, the expression of csuC and csuE genes in strains treated with MIC concentration (0.625 μg/ml) of vancomycin -gold nanoparticles increased, however the expression of bap was decreased compared to the control groups.

CONCLUSION: Due to the inhibitory effect of silver nanoparticles and gold-vancomycin nanoparticles against A. baumannii biofilm formation and genes expression, they can probably be used for prevent of biofilm formation in medical instrument or can be use for treatment of infections with or without antibiotic.}, } @article {pmid36721488, year = {2022}, author = {Kanagasingam, S and von Ruhland, C and Welbury, R and Singhrao, SK}, title = {Ex vivo Detection of Amyloid-β in Naturally Formed Oral Biofilm.}, journal = {Journal of Alzheimer's disease reports}, volume = {6}, number = {1}, pages = {757-773}, pmid = {36721488}, issn = {2542-4823}, abstract = {BACKGROUND: Oral infection has been implicated in the possible etiology of Alzheimer's disease.

OBJECTIVE: To detect amyloid-β (Aβ) within microbial biofilms.

METHODS: Freshly extracted teeth (N = 87) with periodontal disease were separated into Group A (N = 11), with primary root canal infection and Group B (N = 21) with failed endodontic treatment identified by the presence of, gutta percha root filling. Biofilm characteristics were observed by scanning electron microscopy (SEM). Demineralized paraffin wax embedded tooth sections and mineralized calculus biofilm were immunostained with the anti-Aβ antibody. The gutta perchas were processed either for on-section acrylic resin tissue immunocolloidal gold silver staining (IGSS) using the anti-Aβ antibody or in Araldite resin for ultrastructure.

RESULTS: SEM demonstrated calculus and gutta percha in situ harboring a polymicrobial biofilm featuring extracellular polymeric substance (EPS) and water channels. Immunohistochemistry on rehydrated paraffin wax tooth sections from Group A, demonstrated Aβ staining on external (calculus and plaque) and all intracanal infected regions. In Group B, the gutta percha biofilm IGSS gave an inconclusive result for Aβ. Transmission electron microscopy of selected teeth with infected intra-canals (Group A) and 20% of gutta percha biofilm (Group B) EPS contained electron dense fibrils of variable sizes, some of which were typical of human Aβ fibrils.

CONCLUSION: This study detected both soluble and insoluble Aβ fibrils within the EPS of periodontal and endodontic natural biofilm, strongly suggesting its role as an antimicrobial peptide in combatting local infection, with potential risk for cross-seeding into the brain for AD development.}, } @article {pmid36721451, year = {2022}, author = {Sabzi, N and Moniri, R and Sehat, M and Fathizadeh, H and Nazari-Alam, A}, title = {Antimicrobial effect of silver and gold nanoparticles in combination with linezolid on Enterococcus biofilm.}, journal = {Iranian journal of microbiology}, volume = {14}, number = {6}, pages = {863-873}, pmid = {36721451}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: In the past few years, application of new antimicrobial e.g. nanoparticles (NPs) to treat infection caused by drug-resistant bacteria has increased. This study aimed to determine antimicrobial property of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in combination with linezolid on Enterococcus biofilm.

MATERIALS AND METHODS: A total of forty-eight isolates of Enterococcus spp. were collected and confirmed by PCR method. The synthesis of biocompatible AgNPs was performed, then analyzed by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy. We carried out minimum inhibitory concentration (MIC) and biofilm forming capacity of AgNPs and AuNPs with linezolid.

RESULTS: Twenty-two E. faecium isolates and twentysix E. faecalis investigated in this study. Strong biofilm formation was seen in 12 (25%) of isolates, and others isolates (75%) formed moderate biofilm. AgNPs and Au-NPs size were 26 nm and 20 nm respectively. The MIC of AgNPs was 23.2 μg/ml, and AuNPs were 92.1 μg/ml and the lowest MIC was obtained 2 μg/ml in linezolid. Biofilm formation inhibitory activity by AuNPs + Linezolide and AgNPs + Linezolide 70 to 80 percent increased in average.

CONCLUSION: The antibiofilm activity of AgNPs and AuNPs increased when both agents were used in combination with linezolid in comparison with each agent alone.}, } @article {pmid36721450, year = {2022}, author = {Mahmoud, S and Gaber, Y and Khattab, RA and Bakeer, W and Dishisha, T and Ramadan, MA}, title = {The inhibitory effect of dextranases from Bacillus velezensis and Pseudomonas stutzeri on Streptococcus mutans biofilm.}, journal = {Iranian journal of microbiology}, volume = {14}, number = {6}, pages = {850-862}, pmid = {36721450}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium Streptococcus mutans is the leading cause of dental caries. Dextranase is an enzyme that can degrade dextran to low molecular weight fractions, which have many therapeutic and industrial applications. The purpose of the present study was to isolate a novel dextranase-producing bacteria from a source (molasses). The cell-free extracts containing dextranases were tested as antibiofilm agents.

MATERIALS AND METHODS: Dextranase-producing bacteria were identified using phenotypic and genotypic methods such as 16S rRNA gene sequencing and enzymatic characterization.

RESULTS: The highest six dextranase-producing bacterial isolates were Bacillus species. The best conditions for dextranase productivity were obtained after 72 hours of culture time at pH 7. The addition of glucose to the medium enhanced the production of the enzymes. The cell-free extract of the six most active isolates showed remarkable activity against biofilm formation by Streptococcus mutans ATCC 25175. The highest inhibition activities reached 60% and 80% for Bacillus velezensis and Pseudomonas stutzeri, respectively.

CONCLUSION: Therefore, our study added to the current dextranase-producing bacteria with potential as a source of dextranases.}, } @article {pmid36720360, year = {2023}, author = {Afrasiabi, S and Chiniforush, N}, title = {An in vitro study on the efficacy of hydrogen peroxide mediated high-power photodynamic therapy affecting Enterococcus faecalis biofilm formation and dispersal.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {41}, number = {}, pages = {103310}, doi = {10.1016/j.pdpdt.2023.103310}, pmid = {36720360}, issn = {1873-1597}, mesh = {*Photochemotherapy/methods ; Photosensitizing Agents/pharmacology/therapeutic use ; Enterococcus faecalis/radiation effects ; Hydrogen Peroxide/pharmacology ; Biofilms/radiation effects ; Sodium Hypochlorite/pharmacology ; Anti-Bacterial Agents ; Dental Pulp Cavity ; Root Canal Irrigants ; }, abstract = {OBJECTIVE: Biofilms are involved in failure of root canal treatment due to their high resistance to antimicrobial agents, which make their removal as a big challenge. The present study aims at utilizing hydrogen peroxide (HP) plus high frequency laser reinforced antimicrobial photodynamic therapy (a-PDT) as a complementary therapy against Enterococcus faecalis (E. faecalis) at planktonic and biofilm stages.

MATERIALS AND METHODS: E. faecalis at planktonic and biofilm stages was treated with the photosensitizer HP, followed by no irradiation or irradiation with a power of 2.5 W (ʎ = 980 nm). The cell viability, anti-biofilm, anti-metabolic potential, and temperature changes were evaluated.

RESULTS: The combination of HP and 980 nm diode laser intensely boosted antibacterial and anti-biofilm efficacy compared with either component alone, affirming HP reinforcement as a bacteriostatic agent. The maximum effect on biofilm occurs in 5.25% sodium hypochlorite (NaOCl) group. During laser irradiations, the mean of temperature changes remains below 5.6 °C.

CONCLUSIONS: It could be concluded that the HP could improve anti-biofilm efficacy as a photosensitizer in a-PDT.}, } @article {pmid36719505, year = {2023}, author = {Chew, RJJ and Tang, YL and Lin, XYS and Oh, FJB and Sim, RP and Anwar, EJ and Preshaw, PM and Tan, KS}, title = {Toll-like receptor-4 activation by subgingival biofilm and periodontal treatment response.}, journal = {Clinical oral investigations}, volume = {27}, number = {5}, pages = {2139-2147}, pmid = {36719505}, issn = {1436-3771}, mesh = {Humans ; Periodontal Pocket/therapy ; *Toll-Like Receptor 4 ; *Periodontitis/drug therapy ; }, abstract = {OBJECTIVES: This study aims to investigate longitudinally the activation of Toll-like receptor-4 (TLR-4) by subgingival biofilm samples before and after nonsurgical periodontal therapy (NSPT).

MATERIALS AND METHODS: Forty periodontitis patients received NSPT and were reviewed 3 and 6 months post-treatment. Subgingival biofilm was sampled from 4 teeth per patient, at baseline and each follow-up time point. TLR-4 activation was determined using the HEK-BLUE™/hTLR4 system. Changes in TLR-4 activation and probing pocket depths (PPDs) were evaluated using generalised linear models, and the association between TLR-4 activation and pocket reduction (defined as 6-month PPDs ≤ 3mm) was determined using generalised estimating equations.

RESULTS: At 6 months, the mean TLR-4 activation by subgingival biofilm samples was significantly reduced from 11.2AU (95%CI 7.1AU, 15.4AU) to 3.6AU (95%CI 2.3AU, 4.8AU, p < 0.001), paralleling significant reductions in mean PPDs at sampled sites. The response to NSPT was associated with longitudinal TLR-4 activation profiles, with significantly higher TLR-4 activation by subgingival biofilm obtained from sites that did not achieve pocket reduction, compared to sites at which pocket reduction was achieved.

CONCLUSIONS: The activation of TLR-4 by subgingival biofilm samples was reduced after NSPT, and this reduction was significantly associated with the clinical improvements (PPD reductions) at sampled sites.

CLINICAL RELEVANCE: This study demonstrated an association between the longitudinal profile of TLR-4 activation by subgingival biofilm and periodontal treatment response. Longitudinal monitoring of TLR-4 activation by subgingival biofilm may potentially identify non-responsive sites, enabling targeted additional treatment.}, } @article {pmid36716948, year = {2023}, author = {Rozman, U and Filker, S and Kalčíková, G}, title = {Monitoring of biofilm development and physico-chemical changes of floating microplastics at the air-water interface.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {322}, number = {}, pages = {121157}, doi = {10.1016/j.envpol.2023.121157}, pmid = {36716948}, issn = {1873-6424}, mesh = {*Microplastics ; Plastics ; Water ; Chlorophyll A/analysis ; *Water Pollutants, Chemical/analysis ; Biofilms ; Polyethylene ; }, abstract = {Microplastics in the aquatic environment serve as a habitat for microbial life, on which they can form biofilms. However, how the development of the biofilm alters the properties of floating microplastics that are at the air-water interface and, therefore, not fully submerged, is not well understood. In this context, an aging experiment was conducted to monitor biofilm formation and changes in physico-chemical properties of low-density polyethylene (floating) microplastics over time. The growth of the biofilm followed the typical bacterial/biofilm growth phases and reached about 30% of the total mass of the microplastics, while the concentration of extracellular polymeric substances within the biofilm remained stable. Presence of chlorophyll a and urease activity indicated presence of photosynthetic microrganisms within the biofilm which was also confirmed by analysis of the biofilm composition. Chemical characterization by FTIR showed the formation of additional functional groups attributed to the formed biofilm, and SEM imaging showed cracks on the surface of the aged microplastics, indicating incipient degradation of the polyethylene. Moreover, the adsorption capacity of the aged particles for metals (Pb(II)) was 52% higher compared to the pristine ones. Aging increased the density and size of the particles; however, it did not lead to the submersion of the aged particles even after 12 weeks of aging, suggesting that additional environmental processes may influence the transport of microplastics from the air-water interface into the water body.}, } @article {pmid36716932, year = {2023}, author = {Thant, KJW and Anh-Vu, N and Yun-Je, K and Masumi, K and Visvanathan, C}, title = {Performance of pilot-scale membrane aerated biofilm reactors integrated with anoxic nano-biotechnological reactor for domestic wastewater treatment.}, journal = {Chemosphere}, volume = {319}, number = {}, pages = {137927}, doi = {10.1016/j.chemosphere.2023.137927}, pmid = {36716932}, issn = {1879-1298}, mesh = {*Wastewater ; Bioreactors ; Biotechnology ; Nitrification ; Biofilms ; *Water Purification ; Nitrogen ; Waste Disposal, Fluid ; Denitrification ; }, abstract = {Membrane-aerated biofilm reactors (MABRs) have aroused increasing attention due to their excellent performance in treating wastewater, where the membranes behave as bio-carriers for microorganisms and bubbleless air diffusers. The MABR technology has not been fully commercialized due to reactor design and low total nitrogen (TN) removal efficiency at short hydraulic retention times (HRT). In this study, a hybrid system of MABR 1 integrated with an anoxic nano-biotechnological reactor filled with Granulated Nanoscale Oxyhydroxides of Fe (GNOF) media was evaluated to assess the improvement in nitrogen removal performance at 12, 10, and 4 h of HRTs. At the same time, another MABR (MABR 2) was operated individually at 12, 10, 8, 6, 4, and 2 h of HRTs to assess the influence of HRT on nitrogen removal performance. An enhancement in removal performance was reported in the hybrid MABR-GNOF, achieving the highest removal efficiencies of 74.3 ± 3.1% for ammonium nitrogen (NH4[+]-N), 69.8 ± 2.1% for total nitrogen (TN), and 90.9 ± 1.7% for chemical oxygen demand (COD), at 12 h HRT. The hybrid MABR-GNOF system attained 18% higher nitrogen removal than the MABR-only system at 12 h of HRT. A simultaneous anoxic nitrification-denitrification and COD oxidation might be developed for the removal of COD, NH4[+]-N, and TN from domestic wastewater by using GNOF as an electron acceptor in the hybrid MABR-GNOF unit. The findings in this study confirmed the possibility of integration of GNOF and MABR on a pilot scale and are promising for the application of this hybrid system on a full scale.}, } @article {pmid36716802, year = {2023}, author = {Rawindran, H and Syed, R and Alangari, A and Khoo, KS and Lim, JW and Sahrin, NT and Suparmaniam, U and Raksasat, R and Liew, CS and Leong, WH and Kiatkittipong, W and Shahid, MK and Hara, H and Shaharun, MS}, title = {Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene.}, journal = {Environmental research}, volume = {222}, number = {}, pages = {115352}, doi = {10.1016/j.envres.2023.115352}, pmid = {36716802}, issn = {1096-0953}, mesh = {*Chlorella vulgaris ; Surface Properties ; Hydrophobic and Hydrophilic Interactions ; Biofilms ; *Microalgae ; Biomass ; }, abstract = {The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.}, } @article {pmid36714834, year = {2022}, author = {Velsko, IM and Semerau, L and Inskip, SA and García-Collado, MI and Ziesemer, K and Ruber, MS and Benítez de Lugo Enrich, L and Molero García, JM and Valle, DG and Peña Ruiz, AC and Salazar-García, DC and Hoogland, MLP and Warinner, C}, title = {Ancient dental calculus preserves signatures of biofilm succession and interindividual variation independent of dental pathology.}, journal = {PNAS nexus}, volume = {1}, number = {4}, pages = {pgac148}, pmid = {36714834}, issn = {2752-6542}, support = {MR/T022302/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Dental calculus preserves oral microbes, enabling comparative studies of the oral microbiome and health through time. However, small sample sizes and limited dental health metadata have hindered health-focused investigations to date. Here, we investigate the relationship between tobacco pipe smoking and dental calculus microbiomes. Dental calculus from 75 individuals from the 19th century Middenbeemster skeletal collection (Netherlands) were analyzed by metagenomics. Demographic and dental health parameters were systematically recorded, including the presence/number of pipe notches. Comparative data sets from European populations before and after the introduction of tobacco were also analyzed. Calculus species profiles were compared with oral pathology to examine associations between microbiome community, smoking behavior, and oral health status. The Middenbeemster individuals exhibited relatively poor oral health, with a high prevalence of periodontal disease, caries, heavy calculus deposits, and antemortem tooth loss. No associations between pipe notches and dental pathologies, or microbial species composition, were found. Calculus samples before and after the introduction of tobacco showed highly similar species profiles. Observed interindividual microbiome differences were consistent with previously described variation in human populations from the Upper Paleolithic to the present. Dental calculus may not preserve microbial indicators of health and disease status as distinctly as dental plaque.}, } @article {pmid36713201, year = {2022}, author = {Guevara-Lora, I and Bras, G and Juszczak, M and Karkowska-Kuleta, J and Gorecki, A and Manrique-Moreno, M and Dymek, J and Pyza, E and Kozik, A and Rapala-Kozik, M}, title = {Cecropin D-derived synthetic peptides in the fight against Candida albicans cell filamentation and biofilm formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1045984}, pmid = {36713201}, issn = {1664-302X}, abstract = {The recent progressive increase in the incidence of invasive fungal infections, especially in immunocompromised patients, makes the search for new therapies crucial in the face of the growing drug resistance of prevalent nosocomial yeast strains. The latest research focuses on the active compounds of natural origin, inhibiting fungal growth, and preventing the formation of fungal biofilms. Antimicrobial peptides are currently the subject of numerous studies concerning effective antifungal therapy. In the present study, the antifungal properties of two synthetic peptides (ΔM3, ΔM4) derived from an insect antimicrobial peptide - cecropin D - were investigated. The fungicidal activity of both compounds was demonstrated against the yeast forms of Candida albicans, Candida tropicalis, and Candida parapsilosis, reaching a MFC99.9 in the micromolar range, while Candida glabrata showed greater resistance to these peptides. The scanning electron microscopy revealed a destabilization of the yeast cell walls upon treatment with both peptides; however, their effectiveness was strongly modified by the presence of salt or plasma in the yeast environment. The transition of C. albicans cells from yeast to filamentous form, as well as the formation of biofilms, was effectively reduced by ΔM4. Mature biofilm viability was inhibited by a higher concentration of this peptide and was accompanied by increased ROS production, activation of the GPX3 and SOD5 genes, and finally, increased membrane permeability. Furthermore, both peptides showed a synergistic effect with caspofungin in inhibiting the metabolic activity of C. albicans cells, and an additive effect was also observed for the mixtures of peptides with amphotericin B. The results indicate the possible potential of the tested peptides in the prevention and treatment of candidiasis.}, } @article {pmid36712378, year = {2022}, author = {Wang, C and Chantraine, C and Viljoen, A and Herr, AB and Fey, PD and Horswill, AR and Mathelié-Guinlet, M and Dufrêne, YF}, title = {The staphylococcal biofilm protein Aap mediates cell-cell adhesion through mechanically distinct homophilic and lectin interactions.}, journal = {PNAS nexus}, volume = {1}, number = {5}, pages = {pgac278}, pmid = {36712378}, issn = {2752-6542}, support = {R01 AI162964/AI/NIAID NIH HHS/United States ; }, abstract = {The accumulation phase of staphylococcal biofilms relies on both the production of an extracellular polysaccharide matrix and the expression of bacterial surface proteins. A prototypical example of such adhesive proteins is the long multidomain protein Aap (accumulation-associated protein) from Staphylococcus epidermidis, which mediates zinc-dependent homophilic interactions between Aap B-repeat regions through molecular forces that have not been investigated yet. Here, we unravel the remarkable mechanical strength of single Aap-Aap homophilic bonds between living bacteria and we demonstrate that intercellular adhesion also involves sugar binding through the lectin domain of the Aap A region. We find that the mechanical force needed to unfold individual β-sheet-rich G5-E domains from the Aap B-repeat regions is very high, ranging from 300 up to 1,000 pN at high loading rates, indicating these are extremely stable. This high mechanostability provides a means to the cells to form highly adhesive and cohesive biofilms capable of sustaining high physiological shear stress. Importantly, we identify a previously undescribed role of Aap in bacterial-bacterial adhesion, that is, heterophilic sugar binding by a specific lectin domain located in the N-terminal A region, which might be important to establish initial contacts between cells before strong homophilic bonds come into play. This study emphasizes the remarkable mechanical and binding properties of Aap as well as its wide diversity of adhesive functions.}, } @article {pmid36711324, year = {2023}, author = {Nunez, C and Kostoulias, X and Peleg, A and Short, F and Qu, Y}, title = {A comprehensive comparison of biofilm formation and capsule production for bacterial survival on hospital surfaces.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100105}, pmid = {36711324}, issn = {2590-2075}, abstract = {Biofilm formation and capsule production are known microbial strategies used by bacterial pathogens to survive adverse conditions in the hospital environment. The relative importance of these strategies individually is unexplored. This project aims to compare the contributory roles of biofilm formation and capsule production in bacterial survival on hospital surfaces. Representative strains of bacterial species often causing hospital-acquired infections were selected, including Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The importance of biofilm formation and capsule production on bacterial survival was evaluated by comparing capsule-positive wild-type and capsule-deficient mutant strains, and biofilm and planktonic growth modes respectively, against three adverse hospital conditions, including desiccation, benzalkonium chloride disinfection and ultraviolet (UV) radiation. Bacterial survival was quantitatively assessed using colony-forming unit (CFU) enumeration and the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and qualitatively by scanning electron microscopy (SEM). Correlations between capsule production and biofilm formation were further investigated. Biofilm formation contributed significantly to bacterial survival on hospital surface simulators, mediating high resistance to desiccation, benzalkonium chloride disinfection and UV radiation. The role of capsule production was minor and species-specific; encapsulated A. baumannii but not K. pneumoniae cells demonstrated slightly increased resistance to desiccation, and neither showed enhanced resistance to benzalkonium chloride. Interestingly, capsule production sensitized K. pneumoniae and A. baumannii to UV radiation. The loss of capsule in K. pneumoniae and A. baumannii enhanced biofilm formation, possibly by increasing cell surface hydrophobicity. In summary, this study confirms the crucial role of biofilm formation in bacterial survival on hospital surfaces. Conversely, encapsulation plays a relatively minor role and may even negatively impact bacterial biofilm formation and hospital survival.}, } @article {pmid36710254, year = {2023}, author = {Zhao, J and Li, F and Kong, S and Chen, T and Song, H and Wang, Z}, title = {Elongated Riboflavin-Producing Shewanella oneidensis in a Hybrid Biofilm Boosts Extracellular Electron Transfer.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {10}, number = {9}, pages = {e2206622}, pmid = {36710254}, issn = {2198-3844}, support = {2018YFA0901300//National Key Research and Development Program of China/ ; 22278312//National Natural Science Foundation of China/ ; 32071411//National Natural Science Foundation of China/ ; 32001034//National Natural Science Foundation of China/ ; }, mesh = {Electrons ; *Nanotubes, Carbon ; Riboflavin/metabolism ; *Shewanella/metabolism ; Biofilms ; }, abstract = {Shewanella oneidensis is able to carry out extracellular electron transfer (EET), although its EET efficiency is largely limited by low flavin concentrations, poor biofilm forming-ability, and weak biofilm conductivity. After identifying an important role for riboflavin (RF) in EET via in vitro experiments, the synthesis of RF is directed to 837.74 ± 11.42 µm in S. oneidensis. Molecular dynamics simulation reveals RF as a cofactor that binds strongly to the outer membrane cytochrome MtrC, which is correspondingly further overexpressed to enhance EET. Then the cell division inhibitor sulA, which dramatically enhanced the thickness and biomass of biofilm increased by 155% and 77%, respectively, is overexpressed. To reduce reaction overpotential due to biofilm thickness, a spider-web-like hybrid biofilm comprising RF, multiwalled carbon nanotubes (MWCNTs), and graphene oxide (GO) with adsorption-optimized elongated S. oneidensis, achieve a 77.83-fold increase in power (3736 mW m[-2]) relative to MR-1 and dramatically reduce the charge-transfer resistance and boosted biofilm electroactivity. This work provides an elegant paradigm to boost EET based on a synthetic biology strategy and materials science strategy, opens up further opportunities for other electrogenic bacteria.}, } @article {pmid36709299, year = {2023}, author = {Yun, Z and Xianghong, L and Qianhua, G and Qin, D}, title = {Copper ions inhibit Streptococcus mutans-Veillonella parvula dual biofilm by activating Streptococcus mutans reactive nitrogen species.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {48}, pmid = {36709299}, issn = {1472-6831}, mesh = {Humans ; *Streptococcus mutans ; Copper/pharmacology/metabolism ; *Trace Elements/metabolism/pharmacology ; Magnesium/metabolism/pharmacology ; Zinc ; }, abstract = {BACKGROUND: To investigate the inhibition mechanism of copper ions on Streptococcus mutans-Veillonella parvula dual biofilm.

METHODS: S. mutans-V. parvula dual biofilm was constructed and copper ions were added at different concentrations. After the biofilm was collected, RNA-seq and qRT-PCR were then performed to get gene information.

RESULTS: The coculture of S. mutans and V. parvula formed a significantly better dual biofilm of larger biomass than S. mutans mono biofilm. And copper ions showed a more significant inhibitory effect on S. mutans-V. parvula dual biofilm than on S. mutans mono biofilm when copper ions concentration reached 100 µM, and copper ions showed a decreased inhibitory effect on S. gordonii-V. parvula dual biofilm and S. sanguis-V.parvula dual biofilm than on the two mono biofilms as the concentration of copper ions increased. And common trace elements such as iron, magnesium, and zinc showed no inhibitory effect difference on S. mutans-V. parvula dual biofilm. The RNA-seq results showed a significant difference in the expression of a new ABC transporter SMU_651c, SMU_652c, SMU_653c, and S. mutans copper chaperone copYAZ. SMU_651c, SMU_652c, and SMU_653c were predicted to function as nitrite/nitrate transporter-related proteins, which suggested the specific inhibition of copper ions on S. mutans-V. parvula dual biofilm may be caused by the activation of S. mutans reactive nitrogen species.

CONCLUSIONS: Streptococcus mutans and Veillonella parvula are symbiotic, forming a dual biofilm of larger biomass to better resist the external antibacterial substances, which may increase the virulence of S. mutans. While common trace elements such as iron, magnesium, and zinc showed no specific inhibitory effect on S. mutans-V. parvula dual biofilm, copper ion had a unique inhibitory effect on S. mutans-V. parvula dual biofilm which may be caused by activating S. mutans RNS when copper ions concentration reached 250 µM.}, } @article {pmid36709283, year = {2023}, author = {Ham, Y and Kim, TJ}, title = {Synergistic inhibitory activity of Glycyrrhizae Radix and Rubi Fructus extracts on biofilm formation of Streptococcus mutans.}, journal = {BMC complementary medicine and therapies}, volume = {23}, number = {1}, pages = {22}, pmid = {36709283}, issn = {2662-7671}, mesh = {*Streptococcus mutans ; Glycyrrhizic Acid/pharmacology ; Ellagic Acid/pharmacology ; Kinetics ; Plant Extracts/pharmacology ; Biofilms ; *Glycyrrhiza ; }, abstract = {BACKGROUND: Streptococcus mutans is a bacterium that causes oral diseases. Plaque, a biofilm produced by S. mutans and other bacteria, makes it difficult to remove cariogenic oral microorganisms, including biofilm producers. Glucan synthesis by glucosyltransferase is one of the mechanisms underlying plaque formation. This study demonstrates the effectiveness of inhibiting biofilm formation by interfering with the glucosyltransferase activity of S. mutans using edible herbal medicines.

METHODS: This study investigated the inhibitory activity of Glycyrrhizae Radix extract, Rubi Fructus extract, glycyrrhizin from Glycyrrhizae Radix, and ellagic acid from Rubi Fructus against glucosyltransferase activity of S. mutans. Enzyme kinetic analysis identified the mechanism by which glycyrrhizin and ellagic acid inhibit enzyme activity.

RESULTS: The conditions for synergistically inhibiting biofilm formation by combining Glycyrrhizae Radix and Rubi Fructus extracts were identified. Biofilm formation was also synergistically inhibited by mixing their respective active constituents, glycyrrhizin and ellagic acid. Glycyrrhizin and ellagic acid inhibited glucosyltransferase via noncompetitive and uncompetitive mechanisms, respectively, indicating that they inhibit it via distinct mechanisms.

CONCLUSIONS: This study presents an effective oral hygiene method using the synergistic activity of two natural plant extracts to inhibit biofilm formation through different inhibitory mechanisms against glucosyltransferase of S. mutans.}, } @article {pmid36709017, year = {2023}, author = {Pourhajibagher, M and Parker, S and Pourakbari, B and Valian, NK and Raoofian, R and Bahador, A}, title = {Enhancement of hypericin nanoparticle-mediated sonoinduced disruption of biofilm and persister cells of Streptococcus mutans by dermcidin-derived peptide DCD-1L.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {41}, number = {}, pages = {103308}, doi = {10.1016/j.pdpdt.2023.103308}, pmid = {36709017}, issn = {1873-1597}, mesh = {Humans ; Streptococcus mutans ; *Dermcidins/metabolism/pharmacology ; *Dental Caries ; Reactive Oxygen Species/metabolism ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Biofilms ; *Anti-Infective Agents/pharmacology ; }, abstract = {BACKGROUND: Streptococcus mutans is considered a major significant contributor to dental caries and its effective removal is difficult due to the formation of biofilm. Therefore, the development of adjuvant therapeutic strategies with anti-biofilm properties is a promising approach. In the present study, we examined the effect of dermcidin-derived peptide DCD-1 L on the antibacterial activity of hypericin nanoparticle (HypNP)-mediated antimicrobial sonodynamic therapy (aSDT) against persister cells growing- and biofilm cultures of S. mutans.

MATERIALS AND METHODS: Following synthesis and confirmation of HypNP, the fractional inhibitory concentration (FIC) index of HypNP and DCD-1 L was determined by checkerboard assay. Cellular uptake of HypNP-DCD-1 L and generation of endogenous reactive oxygen species (ROS) were assessed and followed by the determination of antimicrobial sonoactivity of HypNP-DCD-1 L against persister cells growing- and biofilm cultures of S. mutans. The water-insoluble extracellular polysaccharide (EPS) and expression of the gtfD, comDE, and smuT genes were then evaluated in persister cells growing- and biofilm cultures of S. mutans.

RESULTS: There was a synergistic activity in the combination of HypNP and DCD-1 L against S. mutans with an FIC index value of 0.37. The HypNP-DCD-1L-mediated aSDT also displayed the highest cellular uptake and endogenous ROS generation by bacterial cells. When biofilm and persister cells of S. mutans were treated with HypNP-DCD-1 L and subsequently exposed to ultrasound waves, 5.1 log and 3.8 log reductions, respectively, in bacterial numbers were observed (P<0.05). According to the data, EPS in both persister cells growing- and biofilm cultures of S. mutans were significantly decreased after exposure to the HypNP-DCD-1L-mediated aSDT (P<0.05). In addition, the quantitative real-time PCR data illustrated the high level of similarities in very low-expression profiles of the gtfD before and after all treated groups for persister cells. While, following HypNP-DCD-1L-mediated aSDT treatment, the expression levels of gtfD, comDE, and smuT were significantly lower in treated persister cells growing- and biofilm cultures of S. mutans in comparison with control groups (P<0.05).

CONCLUSIONS: Combined, the results of this study indicate that ultrasound waves-activated HypNP-DCD-1 L can sonoinactivate S. mutans biofilms and persister cells, as well as reduce effectively pathogenicity potency of S. mutans. Hence, HypNP-DCD-1L-mediated aSDT may be proposed as a promising adjunctive therapeutic approach for dental caries.}, } @article {pmid36707288, year = {2023}, author = {Kraft, L and Ribeiro, VST and Gonçalves, GA and Suss, PH and Tuon, FF}, title = {Comparison of amphotericin B lipid complex, deoxycholate amphotericin B, fluconazole, and anidulafungin activity against Candida albicans biofilm isolated from breakthrough candidemia.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.eimce.2022.07.009}, pmid = {36707288}, issn = {2529-993X}, abstract = {INTRODUCTION: Biofilm formation causes virulence and resistance in Candida albicans. However, little is known about breakthrough candidemia isolates. We evaluated the antifungal activity of fluconazole, anidulafungin, deoxycholate amphotericin B (dAMB), and amphotericin B lipid complex (ABLC) against biofilms of C. albicans isolated from patients with breakthrough candidemia.

METHODS: The present study used strains of C. albicans isolated from breakthrough and non-breakthrough candidemia patients (control group). The susceptibility of planktonic cells to amphotericin B, anidulafungin, and fluconazole was determined by broth microdilution. Antifungal activity in sessile cells was evaluated using the minimum biofilm eradication concentration (MBEC), metabolic activity was estimated by reducing MTT, and biomass was estimated using crystal violet retention.

RESULTS: The planktonic strains were susceptible to amphotericin B, anidulafungin, and fluconazole, with minimum inhibitory concentrations of 1, ≤0.03, and 2mg/L, respectively. However, fluconazole and anidulafungin did not exert an antifungal effect on biofilms. Additionally, dAMB and ABCL reduced the metabolic activity and biomass. However, eradication was only achieved using 16mg/L dAMB. C. albicans isolates of breakthrough candidemia exhibited strong biofilm production, and the in vitro activity of available therapeutic options was poor.

CONCLUSION: In the present study, only dAMB and ABCL exhibited antibiofilm effects against sessile breakthrough candidemia isolates.}, } @article {pmid36706296, year = {2023}, author = {}, title = {Corrigendum: Water Sci Technol (2022) 86 (6): 1578-1589: Degradation of tetracycline wastewater by suspended biochar as carriers in moving bed biofilm reactor, Shaoqin Liu, Hanyu Chen, Xueqi Zhang, Baozhong Zhang, Huina Zhu, Hongxia Chen, Bo Wen, Lefei Chen.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {87}, number = {2}, pages = {508}, doi = {10.2166/wst.2023.017}, pmid = {36706296}, issn = {0273-1223}, } @article {pmid36705272, year = {2023}, author = {Sharan, M and Dhaka, P and Bedi, JS and Singh, R and Mehta, N}, title = {Characterization of chicken eggs associated Escherichia coli and Staphylococcus aureus for biofilm production and antimicrobial resistance traits.}, journal = {Animal biotechnology}, volume = {}, number = {}, pages = {1-12}, doi = {10.1080/10495398.2023.2171423}, pmid = {36705272}, issn = {1532-2378}, abstract = {The present study assessed the prevalence, virulence characteristics, antimicrobial resistance and biofilm-forming ability of E. coli and S. aureus recovered from egg samples in Ludhiana, Punjab. A total of 393 samples from hatcheries (n = 238), retail shops (n = 94), and households (n = 61) were collected. The prevalence of E. coli was observed as 11.70% and 9.16% for S. aureus. A total of 41.30% of E. coli isolates were positive for aggR gene and 52.17% were for fimA gene; while 36.11% of the S. aureus isolates were positive for coa gene. A high proportion of E. coli (76.10%) and S. aureus (69.44%) isolates were resistant toward ≥3 tested antibiotic classes. A total of 39.13% of E. coli isolates were moderate biofilm former, whereas the majority of the S. aureus (41.67%) were weak biofilm former. No significant difference regarding biofilm formation was observed between MDR and non-MDR isolates of E. coli and S. aureus. Biofilm genes viz., fimC and crl were reported in 43.47% and 80.43% of E. coli isolates, respectively; while icaA and icaD genes were reported in 58.34% and 47.22% of S. aureus isolates, respectively. A strong metabolic activity among 52.17% of E. coli and 41.66% of S. aureus isolates was observed using XTT assay. The present study highlights the need for applied food safety measures across the egg production chain of the region to prevent the development of MDR strains and biofilms.}, } @article {pmid36705135, year = {2022}, author = {Pokharel, K and Dawadi, BR and Shrestha, LB}, title = {Role of Biofilm in Bacterial Infection and Antimicrobial Resistance.}, journal = {JNMA; journal of the Nepal Medical Association}, volume = {60}, number = {253}, pages = {836-840}, pmid = {36705135}, issn = {1815-672X}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Staphylococcus aureus/genetics ; *Staphylococcal Infections/microbiology ; Drug Resistance, Bacterial ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. Microbial flora which produces biofilm manifests an altered growth rate and transcribes genes that provide them resistance to antimicrobial and host immune systems. Biofilms protect the invading bacteria against the immune system of the host via impaired activation of phagocytes and the complement system. Biofilm-producing isolates showed greater multidrug resistance than non-biofilm producers. Biofilm causes antibiotic resistance through processes like chromosomally encoded resistant genes, restriction of antibiotics, reduction of growth rate, and host immunity. Biofilm formation is responsible for the development of superbugs like methicillin-resistant Staphylococcus aureus, vancomycin-resistant Staphylococcus aureus, and metallo-beta-lactamase producing Pseudomonas aeruginosa. Regular monitoring of antimicrobial resistance and maintaining hygiene, especially in hospitalized patients are required to control biofilm-related infections in order to prevent antimicrobial resistance.}, } @article {pmid36704568, year = {2022}, author = {Rodríguez-Temporal, D and Díez, R and Díaz-Navarro, M and Escribano, P and Guinea, J and Muñoz, P and Rodríguez-Sánchez, B and Guembe, M}, title = {Determination of the ability of matrix-assisted laser desorption ionization time-of-flight mass spectrometry to identify high-biofilm-producing strains.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1104405}, pmid = {36704568}, issn = {1664-302X}, abstract = {BACKGROUND: The traditional method for assessing the capacity of a microorganism to produce biofilm is generally a static in vitro model in a multi-well plate using the crystal violet (CV) binding assay, which takes 96 h. Furthermore, while the method is simple to perform, its reproducibility is poor.

OBJECTIVE: We evaluated whether matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) could make it possible to differentiate between high-and low-biofilm-producing microorganisms on 24-h cultures of Staphylococcus aureus and Candida albicans.

METHODS: We included 157 strains of S. aureus and 91 strains of C. albicans obtained from the blood cultures of patients with bacteremia/candidemia. We tested biofilm production using the CV binding assay as the gold standard to classify strains as low or high biofilm producers. We then applied MALDI-TOF MS to create a machine learning-based predictive model using 40 strains of S. aureus and C. albicans, each with extreme absorbance values, and validated this approach with the remaining 117 and 51 strains using the random forest algorithm and the support vector machine algorithm, respectively.

RESULTS: Overall, 81.2% of the S. aureus strains (95/117) and 74.5% of the C. albicans strains (38/51) used for validation were correctly categorized, respectively, as low and high-biofilm-producing.

CONCLUSION: Classification based on MALDI-TOF MS protein spectra enables us to predict acceptable information about the capacity of 24-h cultures of S. aureus and C. albicans to form biofilm.}, } @article {pmid36704545, year = {2022}, author = {Costa, MOCE and do Nascimento, APB and Martins, YC and Dos Santos, MT and Figueiredo, AMS and Perez-Rueda, E and Nicolás, MF}, title = {The gene regulatory network of Staphylococcus aureus ST239-SCCmecIII strain Bmb9393 and assessment of genes associated with the biofilm in diverse backgrounds.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1049819}, pmid = {36704545}, issn = {1664-302X}, abstract = {INTRODUCTION: Staphylococcus aureus is one of the most prevalent and relevant pathogens responsible for a wide spectrum of hospital-associated or community-acquired infections. In addition, methicillin-resistant Staphylococcus aureus may display multidrug resistance profiles that complicate treatment and increase the mortality rate. The ability to produce biofilm, particularly in device-associated infections, promotes chronic and potentially more severe infections originating from the primary site. Understanding the complex mechanisms involved in planktonic and biofilm growth is critical to identifying regulatory connections and ways to overcome the global health problem of multidrug-resistant bacteria.

METHODS: In this work, we apply literature-based and comparative genomics approaches to reconstruct the gene regulatory network of the high biofilm-producing strain Bmb9393, belonging to one of the highly disseminating successful clones, the Brazilian epidemic clone. To the best of our knowledge, we describe for the first time the topological properties and network motifs for the Staphylococcus aureus pathogen. We performed this analysis using the ST239-SCCmecIII Bmb9393 strain. In addition, we analyzed transcriptomes available in the literature to construct a set of genes differentially expressed in the biofilm, covering different stages of the biofilms and genetic backgrounds of the strains.

RESULTS AND DISCUSSION: The Bmb9393 gene regulatory network comprises 1,803 regulatory interactions between 64 transcription factors and the non-redundant set of 1,151 target genes with the inclusion of 19 new regulons compared to the N315 transcriptional regulatory network published in 2011. In the Bmb9393 network, we found 54 feed-forward loop motifs, where the most prevalent were coherent type 2 and incoherent type 2. The non-redundant set of differentially expressed genes in the biofilm consisted of 1,794 genes with functional categories relevant for adaptation to the variable microenvironments established throughout the biofilm formation process. Finally, we mapped the set of genes with altered expression in the biofilm in the Bmb9393 gene regulatory network to depict how different growth modes can alter the regulatory systems. The data revealed 45 transcription factors and 876 shared target genes. Thus, the gene regulatory network model provided represents the most up-to-date model for Staphylococcus aureus, and the set of genes altered in the biofilm provides a global view of their influence on biofilm formation from distinct experimental perspectives and different strain backgrounds.}, } @article {pmid36702412, year = {2023}, author = {Yuan, Q and Jia, Z and Roots, P and Wells, G}, title = {A strategy for fast anammox biofilm formation under mainstream conditions.}, journal = {Chemosphere}, volume = {318}, number = {}, pages = {137955}, doi = {10.1016/j.chemosphere.2023.137955}, pmid = {36702412}, issn = {1879-1298}, mesh = {*Anaerobic Ammonia Oxidation ; Bacterial Adhesion ; Anaerobiosis ; Bioreactors/microbiology ; *Ammonium Compounds ; Nitrogen/chemistry ; Biofilms ; Oxidation-Reduction ; Sewage/microbiology ; Denitrification ; }, abstract = {One of the bottlenecks to applying anaerobic ammonium oxidation (Anammox) is the long start-up time, especially under mainstream conditions. This study proposed a strategy for fast anammox biofilm formation under mainstream conditions. By first cultivating an aerobic heterotrophic biofilm, and then transferring to anoxic conditions, a pre-cultivated heterotrophic biofilm can be formed in 12 days. The pre-cultivated heterotrophic biofilm then functions as a "glue" to accelerate anammox bacteria adhesion and biofilm formation. Secondary settled effluent with externally added 15-30 mg-N·L[-1] ammonium and nitrite was applied as reactor influent. With a single inoculation of suspended growth anammox-laden biomass and no bioaugmentation, an anammox-enriched biofilm formed after 5 months of operation under uncontrolled temperature of 15-20 °C. Both the nitrogen removal rate and specific anammox activity exponentially increased over the course of study, corresponding to an estimated anammox doubling time of 10.8 days. The biofilm thickness on primed carriers was 2-3 times higher than on the non-primed carriers over the first 5 months of operation, and the hszA gene copy number in primed biofilms revealed was consistently 1 to 2 times higher than the non-primed carrier biofilm, indicating that biofil m carrier priming via selection for a pre-cultivated heterotrophic biofilm base can effectively improve the anammox enrichment rate at early stages of reactor operation. Time, rather than the type of biofilm (primed versus non-primed), had a stronger influence on microbial community structure over the full 230 days of reactor operation. Candidatus Brocadia was the only detected anammox bacteria genus. Overall, pre-cultivation of heterotrophs on biofilm carriers provides a simple route to accelerate anammox-enriched biofilm formation under mainstream conditions.}, } @article {pmid36702020, year = {2023}, author = {Jang, Y and Lee, SH and Kim, NK and Ahn, CH and Rittmann, BE and Park, HD}, title = {Biofilm characteristics for providing resilient denitrification in a hydrogen-based membrane biofilm reactor.}, journal = {Water research}, volume = {231}, number = {}, pages = {119654}, doi = {10.1016/j.watres.2023.119654}, pmid = {36702020}, issn = {1879-2448}, mesh = {*Denitrification ; *Hydrogen ; Bioreactors ; Nitrates/metabolism ; Biofilms ; Nitrogen ; }, abstract = {In a hydrogen-based membrane biofilm reactor (H2-MBfR), the biofilm thickness is considered to be one of the most important factors for denitrification. Thick biofilms in MBfRs are known for low removal fluxes owing to their resistance to substrate transport. In this study, the H2-MBfR was operated under various loading rates of oxyanions, such as NO3-N, SO4-S, and ClO4[-] at an H2 flux of 1.06 e[-] eq/m[2]-d. The experiment was initiated with NO3-N, SO4-S, and ClO4[-] loadings of 0.464, 0.026, and 0.211 e[-] eq/m[2]-d, respectively, at 20 °C. Under the most stressful conditions, the loading rates increased simultaneously to 1.911, 0.869, and 0.108 e[-] eq/m[2]-d, respectively, at 10 °C. We observed improved performance in significantly thicker biofilms (approximately 2.7 cm) compared to previous studies using a denitrifying H2-MBfR for 120 days. Shock oxyanion loadings led to a decrease in total nitrogen (TN) removal by 20 to 30%, but TN removal returned to 100% within a few days. Similarly, complete denitrification was observed, even at 10 °C. The protective function and microbial diversity of the thick biofilm may allow stable denitrification despite stress-imposing conditions. In the microbial community analysis, heterotrophs were dominant and acetogens accounted for 11% of the biofilm. Metagenomic results showed a high abundance of functional genes involved in organic carbon metabolism and homoacetogenesis. Owing to the presence of organic compounds produced by acetogens and autotrophs, heterotrophic denitrification may occur simultaneously with autotrophic denitrification. As a result, the total removal flux of oxyanions (1.84 e[-] eq/m[2]-d) far exceeded the H2 flux (1.06 e[-] eq/m[2]-d). Thus, the large accumulation of biofilms could contribute to good resilience and enhanced removal fluxes.}, } @article {pmid36700647, year = {2023}, author = {Barraza, I and Pajon, C and Diaz-Tang, G and Marin Meneses, E and Abu-Rumman, F and García-Diéguez, L and Castro, V and Lopatkin, AJ and Smith, RP}, title = {Disturbing the Spatial Organization of Biofilm Communities Affects Expression of agr-Regulated Virulence Factors in Staphylococcus aureus.}, journal = {Applied and environmental microbiology}, volume = {89}, number = {2}, pages = {e0193222}, pmid = {36700647}, issn = {1098-5336}, mesh = {Humans ; *Staphylococcus aureus/metabolism ; Virulence Factors/genetics/metabolism ; Trans-Activators/genetics/metabolism ; Biofilms ; *Staphylococcal Infections/microbiology ; Quorum Sensing ; Peptides/metabolism ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Staphylococcus aureus uses quorum sensing and nutrient availability to control the expression of agr-regulated virulence factors. Quorum sensing is mediated by autoinducing peptide (AIP), which at a high concentration reduces expression of surface attachment proteins (coa, fnbpA) and increases expression of exotoxins (lukS) and proteases (splA). Nutrient availability can be sensed through the saeS/saeR system. Low nutrients increase expression of saeR, which augments expression of coa and fnbpA, distinct from the activity of AIP. The formation of spatial structure, such as biofilms, can alter quorum sensing and nutrient acquisition. In natural environments, biofilms encounter forces that may alter their spatial structure. These forces may impact quorum sensing and/or nutrient acquisition and thus affect the expression of agr-regulated virulence factors. However, this has not been studied. We show that periodically disturbing biofilms composed of S. aureus using a physical force affected the expression of agr-regulated virulence factors. In nutrient-poor environments, disturbance increased the expression of coa, fnbpA, lukS, and splA. Disturbance in a nutrient-rich environment at low or high disturbance amplitudes moderately reduced expression of coa and fnbpA but increased expression of lukS and splA. Interestingly, at an intermediate amplitude, the overall expression of agr-regulated virulence factors was the lowest; expression of lukS and splA remained unchanged relative to an undisturbed biofilm, while expression of coa and fnbpA significantly decreased. We hypothesize that these changes are a result of disturbance-driven changes in access to AIP and nutrients. Our results may allow the identification of environments where virulence is enhanced, or reduced, owing to a disturbance. IMPORTANCE Bacteria, such as Staphylococcus aureus, integrate signals from the environment to regulate genes encoding virulence factors. These signals include those produced by quorum-sensing systems and nutrient availability. We show that disturbing the spatial organization of S. aureus populations can lead to changes in the expression of virulence factors, likely by altering the ways in which S. aureus detects these signals. Our work may allow us to identify environments that increase or reduce the expression of virulence factors in S. aureus.}, } @article {pmid36699726, year = {2022}, author = {Shen, Y and Yu, F and Qiu, L and Gao, M and Xu, P and Zhang, L and Liao, X and Wang, M and Hu, X and Sun, Y and Pan, Y}, title = {Ecological influence by colonization of fluoride-resistant Streptococcus mutans in oral biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1106392}, pmid = {36699726}, issn = {2235-2988}, mesh = {Humans ; *Streptococcus mutans ; Fluorides/pharmacology ; In Situ Hybridization, Fluorescence ; *Dental Caries ; RNA, Ribosomal, 16S/genetics ; Biofilms ; }, abstract = {BACKGROUND: Dental caries is one of the oldest and most common infections in humans. Improved oral hygiene practices and the presence of fluoride in dentifrices and mouth rinses have greatly reduced the prevalence of dental caries. However, increased fluoride resistance in microbial communities is concerning. Here, we studied the effect of fluoride-resistant Streptococcus mutans (S. mutans) on oral microbial ecology and compare it with wild-type S. mutans in vitro.

METHODS: Biofilm was evaluated for its polysaccharide content, scanning electron microscopy (SEM) imaging, acid-producing ability, and related lactic dehydrogenase (LDH), arginine deiminase (ADS), and urease enzymatic activity determination. Fluorescence in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (qRT-PCR) were used to evaluate the S. mutans ratio within the biofilm. It was followed by 16S rRNA sequencing to define the oral microbial community.

RESULTS: Fluoride-resistant S. mutans produced increased polysaccharides in presence of NaF (P < 0.05). The enzymatic activities related to both acid and base generation were less affected by the fluoride. In presence of 275 ppm NaF, the pH in the fluoride-resistant strain sample was lower than the wild type. We observed that with the biofilm development and accumulative fluoride concentration, the fluoride-resistant strain had positive relationships with other bacteria within the oral microbial community, which enhanced its colonization and survival. Compared to the wild type, fluoride-resistant strain significantly increased the diversity and difference of oral microbial community at the initial stage of biofilm formation (4 and 24 h) and at a low fluoride environment (0 and 275 ppm NaF) (P < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that fluoride-resistant strain enhanced the metabolic pathways and glucose transfer.

CONCLUSIONS: Fluoride-resistant S. mutans affected the microecological balance of oral biofilm and its cariogenic properties in vitro, indicating its negative impact on fluoride's caries prevention effect.}, } @article {pmid36699581, year = {2022}, author = {Liu, S and Xiong, Y and Xiao, H and Zheng, J and Wen, Z and Li, D and Deng, Q and Yu, Z}, title = {Inhibition of planktonic growth and biofilm formation of Staphylococcus aureus by entrectinib through disrupting the cell membrane.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1106319}, pmid = {36699581}, issn = {1664-302X}, abstract = {Over the last few decades, Staphylococcus aureus infection remain a major medical challenge and health concern worldwide. Biofilm formation and antibiotic resistance caused by S. aureus make it difficult to be eradicated from bacterial infections in clinics. In this study, our data demonstrated the antibacterial and excellent anti-biofilm activity of entrectinib against S. aureus. Entrectinib also exhibited the good safety, suggesting no toxicity with antibacterial concentration of entrectinib toward the erythrocytes and mammalian 239 T cells. Moreover, entrectinib significantly reduced the bacterial burden of septic tissue in a murine model of MRSA infection. Global proteomic analysis of S. aureus treated with entrectinib showed significant changes in the expression levels of ribosomal structure-related (rpmC, rpmD, rplX, and rpsT) and oxidative stress-related proteins (Thioredoxin system), suggesting the possible inhibition of bacterial protein biosynthesis with entrectinib exposure. The increased production of reactive oxygen species (ROS) was demonstrated in the entrectinib-treated S. aureus, supported the impact of entrectinib on the expression changes of ROS-correlated proteins involved in oxidative stress. Furthermore, entrectinib-induced resistant S. aureus clone was selected by in vitro induction under entrectinib exposure and 3 amino acid mutations in the entrectinib-induced resistant S. aureus strain, 2 of which were located in the gene encoding Type II NADH: quinoneoxidoreductase and one were found in GTP pyrophosphokinase family protein. Finally, the bactericidal action of entrectinib on S. aureus were confirmed by disrupting the bacterial cell membrane. Conclusively, entrectinib exhibit the antibacterial and anti-biofilm activity by destroying cell membrane against S. aureus.}, } @article {pmid36698450, year = {2022}, author = {Hussain Akbar, J and Behbehani, J and Karched, M}, title = {Biofilm growth and microbial contamination of dental unit waterlines at Kuwait University dental center.}, journal = {Frontiers in oral health}, volume = {3}, number = {}, pages = {1071018}, pmid = {36698450}, issn = {2673-4842}, abstract = {Biofilm formation in dental unit waterlines and the resulting microbial contamination of the water in the system has become a significant problem. Contaminated water in the dental units is a major concern in dental clinics due to potential risk of causing infections particularly in elderly and immunocompromised patients. The aim of this study was at first to determine microbial contamination of the dental unit waterlines and then to study the efficacy of a comprehensive disinfection protocol on decreasing the microbial load. Water samples were collected before and after disinfection procedure from handpieces and water storage bottles from the dental units, a small 1-cm tubing was cut from each unit and subjected to microbiological culture on different growth media. Identification of the predominant species was achieved by 16S rRNA gene sequencing. Microbial growth was observed in samples collected from all dental units. Upon disinfection procedure, microbial contamination in the water samples and in the tubing surfaces was significantly reduced (P > 0.05). 16S rRNA gene sequencing revealed the presence of several species belonging to the genera Staphylococcus, Corynebacterium and Roseomonas, some of which are implicated in human infections. Aggravation of the biofilm growth on the tubing surfaces and the microbial contamination in the water can be effectively controlled by implementing appropriate and routine disinfection protocols. This may help protect the dental unit staff and the patients being exposed to the risk of infections.}, } @article {pmid36697414, year = {2023}, author = {Mourer, T and El Ghalid, M and Pehau-Arnaudet, G and Kauffmann, B and Loquet, A and Brûlé, S and Cabral, V and d'Enfert, C and Bachellier-Bassi, S}, title = {The Pga59 cell wall protein is an amyloid forming protein involved in adhesion and biofilm establishment in the pathogenic yeast Candida albicans.}, journal = {NPJ biofilms and microbiomes}, volume = {9}, number = {1}, pages = {6}, pmid = {36697414}, issn = {2055-5008}, mesh = {Humans ; Amyloid/metabolism ; *Amyloidogenic Proteins/genetics/metabolism ; *Biofilms ; *Candida albicans/genetics/metabolism ; *Cell Wall/genetics/metabolism ; *Fungal Proteins/genetics/metabolism ; }, abstract = {The human commensal fungus Candida albicans can attach to epithelia or indwelling medical devices and form biofilms, that are highly tolerant to antifungal drugs and can evade the immune response. The cell surface protein Pga59 has been shown to influence adhesion and biofilm formation. Here, we present evidence that Pga59 displays amyloid properties. Using electron microscopy, staining with an amyloid fibre-specific dye and X-ray diffraction experiments, we showed that the predicted amyloid-forming region of Pga59 is sufficient to build up an amyloid fibre in vitro and that recombinant Pga59 can also adopt a cross-β amyloid fibre architecture. Further, mutations impairing Pga59 amyloid assembly led to diminished adhesion to substrates and reduced biofilm production. Immunogold labelling on amyloid structures extracted from C. albicans revealed that Pga59 is used by the fungal cell to assemble amyloids within the cell wall in response to adhesion. Altogether, our results suggest that Pga59 amyloid properties are used by the fungal cell to mediate cell-substrate interactions and biofilm formation.}, } @article {pmid36696596, year = {2023}, author = {Kim, J and Choi, Y and Park, J and Choi, J}, title = {Gelatin-Gallic Acid Microcomplexes Release GO/Cu Nanomaterials to Eradicate Antibiotic-Resistant Microbes and Their Biofilm.}, journal = {ACS infectious diseases}, volume = {9}, number = {2}, pages = {296-307}, doi = {10.1021/acsinfecdis.2c00439}, pmid = {36696596}, issn = {2373-8227}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology/chemistry ; Gelatin/chemistry ; Spectroscopy, Fourier Transform Infrared ; Biofilms ; *Nanostructures ; *Anti-Infective Agents ; Bacteria ; }, abstract = {Wound-infecting bacteria are typically Pseudomonas aeruginosa and Staphylococcus epidermidis, both of which form biofilms and become resistant to antibiotics. To solve this problem, copper nanoparticles (Cu) on graphene oxide (GO) nanosheets were used as antibacterial materials. Since the excessive use of antibacterial substances is fatal to normal tissues, GO/Cu was encapsulated with a gelatin complex to lower the cytotoxicity. Among the catechol-based substances, gallic acid (GA), which has anti-inflammatory and antibacterial properties, was used in this study to impart stability to the gelatin complex. Gelatin (GE) and gallic acid (GA) were combined by a crosslinking method using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysuccinimide (NHS) as a crosslinker, and the crosslinking was confirmed by Fourier transform infrared (FT-IR), [1]H NMR, and the fluorescence property of GA. The GO/Cu@GE-GA microcomplexes exhibited more antibacterial effect against Gram-positive bacteria (S. epidermidis) and Gram-negative bacteria (P. aeruginosa) than when GO/Cu alone was used, and the antibiofilm effect was also confirmed. The cytotoxicity evaluation for human skin cells (human dermal fibroblast (HDF)) at the same concentration showed that it had low cytotoxicity and biocompatibility. This study shows the potential of antimicrobial gelatin microcomplex in prohibiting infectious bacteria and their biofilms and controlling the release of antimicrobial substances.}, } @article {pmid36696507, year = {2023}, author = {Dubern, JF and Hook, AL and Carabelli, AM and Chang, CY and Lewis-Lloyd, CA and Luckett, JC and Burroughs, L and Dundas, AA and Humes, DJ and Irvine, DJ and Alexander, MR and Williams, P}, title = {Discovery of a polymer resistant to bacterial biofilm, swarming, and encrustation.}, journal = {Science advances}, volume = {9}, number = {4}, pages = {eadd7474}, pmid = {36696507}, issn = {2375-2548}, mesh = {Humans ; *Polymers ; Urinary Catheterization ; Biofilms ; Urinary Catheters/microbiology ; *Urinary Tract Infections/prevention & control/microbiology ; Bacteria ; Escherichia coli ; }, abstract = {Innovative approaches to prevent catheter-associated urinary tract infections (CAUTIs) are urgently required. Here, we describe the discovery of an acrylate copolymer capable of resisting single- and multispecies bacterial biofilm formation, swarming, encrustation, and host protein deposition, which are major challenges associated with preventing CAUTIs. After screening ~400 acrylate polymers, poly(tert-butyl cyclohexyl acrylate) was selected for its biofilm- and encrustation-resistant properties. When combined with the swarming inhibitory poly(2-hydroxy-3-phenoxypropyl acrylate), the copolymer retained the bioinstructive properties of the respective homopolymers when challenged with Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Urinary tract catheterization causes the release of host proteins that are exploited by pathogens to colonize catheters. After preconditioning the copolymer with urine collected from patients before and after catheterization, reduced host fibrinogen deposition was observed, and resistance to diverse uropathogens was maintained. These data highlight the potential of the copolymer as a urinary catheter coating for preventing CAUTIs.}, } @article {pmid36696490, year = {2023}, author = {Xiu, W and Ren, L and Xiao, H and Zhang, Y and Wang, D and Yang, K and Wang, S and Yuwen, L and Li, X and Dong, H and Li, Q and Mou, Y and Zhang, Y and Yin, Z and Liang, B and Gao, Y and Wang, L}, title = {Ultrasound-responsive catalytic microbubbles enhance biofilm elimination and immune activation to treat chronic lung infections.}, journal = {Science advances}, volume = {9}, number = {4}, pages = {eade5446}, doi = {10.1126/sciadv.ade5446}, pmid = {36696490}, issn = {2375-2548}, mesh = {Animals ; Mice ; *Microbubbles ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Bacterial Infections ; Piperacillin/metabolism ; Lung ; Pseudomonas aeruginosa ; }, abstract = {Efficient treatment of chronic lung infections caused by Pseudomonas aeruginosa biofilms is a great challenge because of drug tolerance and immune evasion issues. Here, we develop ultrasound-responsive catalytic microbubbles with biofilm elimination and immune activation properties to combat chronic lung infection induced by P. aeruginosa biofilms. In these microbubbles, piperacillin and Fe3O4 nanoparticles form a drug-loaded shell surrounding the air core. Under ultrasound stimulation, the microbubbles can physically disrupt the structure of biofilms and enhance the penetration of both Fe3O4 nanoparticles and piperacillin into the biofilm. Then, Fe3O4 nanoparticles chemically degrade the biofilm matrix and kill the bacteria with the assistance of piperacillin. Fe3O4 nanoparticles can activate the immune response for biofilm elimination by polarizing macrophages into a pro-inflammatory phenotype. These ultrasound-responsive catalytic microbubbles efficiently treat chronic lung infections in a mouse model by combining physical/chemical/antibiotic biofilm elimination and immune activation, thus providing a promising strategy for combating bacterial biofilm infections.}, } @article {pmid36696432, year = {2023}, author = {Cravener, MV and Do, E and May, G and Zarnowski, R and Andes, DR and McManus, CJ and Mitchell, AP}, title = {Reinforcement amid genetic diversity in the Candida albicans biofilm regulatory network.}, journal = {PLoS pathogens}, volume = {19}, number = {1}, pages = {e1011109}, pmid = {36696432}, issn = {1553-7374}, support = {R01 AI146103/AI/NIAID NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {*Candida albicans/genetics/metabolism ; *Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal ; Transcription Factors/genetics/metabolism ; Biofilms ; Mutation ; Hyphae/genetics ; }, abstract = {Biofilms of the fungal pathogen Candida albicans include abundant long filaments called hyphae. These cells express hypha-associated genes, which specify diverse virulence functions including surface adhesins that ensure biofilm integrity. Biofilm formation, virulence, and hypha-associated gene expression all depend upon the transcription factor Efg1. This transcription factor has been characterized extensively in the C. albicans type strain SC5314 and derivatives, but only recently has its function been explored in other clinical isolates. Here we define a principal set of Efg1-responsive genes whose expression is significantly altered by an efg1Δ/Δ mutation across 17 clinical isolates. This principal gene set includes 68 direct Efg1 targets, whose 5' regions are bound by Efg1 in five clinical isolates, and 42 indirect Efg1 targets, whose 5' regions are not detectably bound by Efg1. Three direct Efg1 target genes encode transcription factors-BRG1, UME6, and WOR3 -whose increased expression in an efg1Δ/Δ mutant restores expression of multiple indirect and direct principal targets, as well as biofilm formation ability. Although BRG1 and UME6 are well known positive regulators of hypha-associated genes and biofilm formation, WOR3 is best known as an antagonist of Efg1 in the sexual mating pathway. We confirm the positive role of WOR3 in biofilm formation with the finding that a wor3Δ/Δ mutation impairs biofilm formation in vitro and in an in vivo biofilm model. Positive control of Efg1 direct target genes by other Efg1 direct target genes-BRG1, UME6, and WOR3 -may buffer principal Efg1-responsive gene expression against the impact of genetic variation in the C. albicans species.}, } @article {pmid36695920, year = {2023}, author = {Tambassi, M and Passarini, E and Menozzi, I and Berni, M and Bracchi, C and Dodi, A and Bolzoni, L and Scaltriti, E and Morganti, M and Ferrarini, G and Sordi, L and Sarti, M and Ambretti, S and Pongolini, S}, title = {Klebsiella pneumoniae carrying multiple alleles of antigen 43-encoding gene of Escherichia coli associated with biofilm formation.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {42}, number = {3}, pages = {371-377}, pmid = {36695920}, issn = {1435-4373}, mesh = {Alleles ; Anti-Bacterial Agents ; Antigens, Bacterial/genetics ; Biofilms ; Colistin ; Escherichia coli/genetics ; *Escherichia coli Proteins/genetics ; *Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; Plasmids/genetics ; }, abstract = {A clinical strain of Klebsiella pneumoniae typed as sequence type 307 carrying three different alleles of the flu gene encoding the Escherichia coli virulence factor antigen 43 associated with biofilm formation was detected and characterized. The flu alleles are located in the chromosome inside putative integrative conjugative elements. The strain displays the phenotypes associated with Ag43, i.e. bi-phasic colony morphology and enhanced biofilm production. Furthermore, the strain produces low amount of capsule known to affect Ag43 function. Analysis of 1431 worldwide deposited genomes revealed that 3.7% Klebsiella pneumoniae carry one or two flu alleles.}, } @article {pmid36694584, year = {2022}, author = {Radwan, AA and Darwesh, OM and Emam, MT and Mohamed, KA and Shady, HMA}, title = {A combined treatment of Proteinase K and biosynthesized ZnO-NPs for eradication of dairy biofilm of sporeformers.}, journal = {AIMS microbiology}, volume = {8}, number = {4}, pages = {507-527}, pmid = {36694584}, issn = {2471-1888}, abstract = {Biofilms of sporeformers found in the dairy industry are the major contaminants during processing, as they withstand heat and chemical treatment that are used to control microbes. The present work is aimed to remove these resistant forms of bacterial community (biofilm) present in dairy production lines using ecofriendly agents based on proteinase K (Prot-K) coupled with Zinc oxide nanoparticles (ZnO-NPs). Some metal/metal oxide (Ag, CuO and ZnO) NPs were prepared microbially, and ZnO-NPs were characterized as the most effective ones among them. The produced ZnO-NPs were 15-25 nm in size with spherical shape, and FTIR analysis confirmed the presence of proteins and alkanes surrounding particles as capping agents. Application of Prot-K for eradication (removal) of a model biofilm of mixed sporeformers on food-grade stainless steel resulted in an 83% reduction in the absorbance of crystal violet-stained biofilm. When Prot-K was mixed with the biosynthesized NPs ZnO_G240, the reduction increased to 99.19%. This finding could contribute to an efficient cleaning approach combined with CIP to remove the recalcitrant biofilms in dairy production lines.}, } @article {pmid36691521, year = {2023}, author = {Pham, LHP and Ly, KL and Colon-Ascanio, M and Ou, J and Wang, H and Lee, SW and Wang, Y and Choy, JS and Phillips, KS and Luo, X}, title = {Dissolvable alginate hydrogel-based biofilm microreactors for antibiotic susceptibility assays.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100103}, pmid = {36691521}, issn = {2590-2075}, abstract = {Biofilms are found in many infections in the forms of surface-adhering aggregates on medical devices, small clumps in tissues, or even in synovial fluid. Although antibiotic resistance genes are studied and monitored in the clinic, the structural and phenotypic changes that take place in biofilms can also lead to significant changes in how bacteria respond to antibiotics. Therefore, it is important to better understand the relationship between biofilm phenotypes and resistance and develop approaches that are compatible with clinical testing. Current methods for studying antimicrobial susceptibility are mostly planktonic or planar biofilm reactors. In this work, we develop a new type of biofilm reactor-three-dimensional (3D) microreactors-to recreate biofilms in a microenvironment that better mimics those in vivo where bacteria tend to form surface-independent biofilms in living tissues. The microreactors are formed on microplates, treated with antibiotics of 1000 times of the corresponding minimal inhibitory concentrations (1000 × MIC), and monitored spectroscopically with a microplate reader in a high-throughput manner. The hydrogels are dissolvable on demand without the need for manual scraping, thus enabling measurements of phenotypic changes. Bacteria inside the biofilm microreactors are found to survive exposure to 1000 × MIC of antibiotics, and subsequent comparison with plating results reveals no antibiotic resistance-associated phenotypes. The presented microreactor offers an attractive platform to study the tolerance and antibiotic resistance of surface-independent biofilms such as those found in tissues.}, } @article {pmid36690856, year = {2023}, author = {Pápai, M and Benedek, T and Táncsics, A and Bornemann, TLV and Plewka, J and Probst, AJ and Hussein, D and Maróti, G and Menashe, O and Kriszt, B}, title = {Selective enrichment, identification, and isolation of diclofenac, ibuprofen, and carbamazepine degrading bacteria from a groundwater biofilm.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {15}, pages = {44518-44535}, pmid = {36690856}, issn = {1614-7499}, support = {ÚNKP-22-3-II//Ministry for Innovation and Technology/ ; GeneOil//Lundin Energy Norway/ ; }, mesh = {*Ibuprofen/analysis ; Diclofenac/chemistry ; Ecosystem ; Carbamazepine/analysis ; Bacteria/metabolism ; Biodegradation, Environmental ; *Groundwater ; Biofilms ; Pharmaceutical Preparations ; }, abstract = {Diclofenac, ibuprofen, and carbamazepine are three of the most widely detected and most concerning pharmaceutical residues in aquatic ecosystems. The aim of this study was to identify bacteria that may be involved in their degradation from a bacterial biofilm. Selective enrichment cultures in mineral salt solution containing pharmaceutical compounds as sole source of carbon and energy were set up, and population dynamics were monitored using shotgun metagenome sequencing. Bacterial genomes were reconstructed using genome-resolved metagenomics. Thirty bacterial isolates were obtained, identified at species level, and tested regarding pharmaceutical biodegradation at an initial concentration of 1.5 mg l[-1]. The results indicated that most probably diclofenac biodegrading cultures consisted of members of genera Ferrovibrio, Hydrocarboniphaga, Zavarzinia, and Sphingopyxis, while in ibuprofen biodegradation Nocardioides and Starkeya, and in carbamazepine biodegradation Nocardioides, Pseudonocardia, and Sphingopyxis might be involved. During the enrichments, compared to the initial state the percentage relative abundance of these genera increased up to three orders of magnitude. Except Starkeya, the genomes of these bacteria were reconstructed and annotated. Metabolic analyses of the annotated genomes indicated that these bacteria harbored genes associated with pharmaceutical biodegradation. Stenotrophomonas humi DIC_5 and Rhizobium daejeonense IBU_18 isolates eliminated diclofenac and ibuprofen during the tests in the presence of either glucose (3 g l[-1]) or in R2A broth. Higher than 90% concentration reduction was observed in the case of both compounds.}, } @article {pmid36690667, year = {2023}, author = {Sugimoto, S and Kinjo, Y}, title = {Instantaneous Clearing of Biofilm (iCBiofilm): an optical approach to revisit bacterial and fungal biofilm imaging.}, journal = {Communications biology}, volume = {6}, number = {1}, pages = {38}, pmid = {36690667}, issn = {2399-3642}, support = {20H02904//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 22H04889//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; JPMJER1502//MEXT | JST | Exploratory Research for Advanced Technology (ERATO)/ ; }, mesh = {*Bacteria ; *Biofilms ; Microscopy, Confocal/methods ; }, abstract = {Whole-biofilm imaging at single-cell resolution is necessary for system-level analysis of cellular heterogeneity, identification of key matrix component functions and response to immune cells and antimicrobials. To this end, we developed a whole-biofilm clearing and imaging method, termed instantaneous clearing of biofilm (iCBiofilm). iCBiofilm is a simple, rapid, and efficient method involving the immersion of biofilm samples in a refractive index-matching medium, enabling instant whole-biofilm imaging with confocal laser scanning microscopy. We also developed non-fixing iCBiofilm, enabling live and dynamic imaging of biofilm development and actions of antimicrobials. iCBiofilm is applicable for multicolor imaging of fluorescent proteins, immunostained matrix components, and fluorescence labeled cells in biofilms with a thickness of several hundred micrometers. iCBiofilm is scalable from bacterial to fungal biofilms and can be used to observe biofilm-neutrophil interactions. iCBiofilm therefore represents an important advance for examining the dynamics and functions of biofilms and revisiting bacterial and fungal biofilm formation.}, } @article {pmid36690637, year = {2023}, author = {Hemdan, BA and El-Taweel, GE and Naha, S and Goswami, P}, title = {Bacterial community structure of electrogenic biofilm developed on modified graphite anode in microbial fuel cell.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {1255}, pmid = {36690637}, issn = {2045-2322}, support = {(Project No.: BSBEPDxDBT00389BAM001/19-1436//Department of Biotechnology-The world academy of sciences (DBT-TWAS)/ ; (Project No.: BSBEPDxDBT00389BAM001/19-1436//Department of Biotechnology-The world academy of sciences (DBT-TWAS)/ ; }, mesh = {*Bioelectric Energy Sources/microbiology ; *Graphite/chemistry ; RNA, Ribosomal, 16S/genetics ; Biofilms ; Bacteria/genetics ; Electrodes ; Firmicutes/genetics ; }, abstract = {Formation of electrogenic microbial biofilm on the electrode is critical for harvesting electrical power from wastewater in microbial biofuel cells (MFCs). Although the knowledge of bacterial community structures in the biofilm is vital for the rational design of MFC electrodes, an in-depth study on the subject is still awaiting. Herein, we attempt to address this issue by creating electrogenic biofilm on modified graphite anodes assembled in an air-cathode MFC. The modification was performed with reduced graphene oxide (rGO), polyaniline (PANI), and carbon nanotube (CNTs) separately. To accelerate the growth of the biofilm, soybean-potato composite (plant) powder was blended with these conductive materials during the fabrication of the anodes. The MFC fabricated with PANI-based anode delivered the current density of 324.2 mA cm[-2], followed by CNTs (248.75 mA cm[-2]), rGO (193 mA cm[-2]), and blank (without coating) (151 mA cm[-2]) graphite electrodes. Likewise, the PANI-based anode supported a robust biofilm growth containing maximum bacterial cell densities with diverse shapes and sizes of the cells and broad metabolic functionality. The alpha diversity of the biofilm developed over the anode coated with PANI was the loftiest operational taxonomic unit (2058 OUT) and Shannon index (7.56), as disclosed from the high-throughput 16S rRNA sequence analysis. Further, within these taxonomic units, exoelectrogenic phyla comprising Proteobacteria, Firmicutes, and Bacteroidetes were maximum with their corresponding level (%) 45.5, 36.2, and 9.8. The relative abundance of Gammaproteobacteria, Clostridia, and Bacilli at the class level, while Pseudomonas, Clostridium, Enterococcus, and Bifidobacterium at the genus level were comparatively higher in the PANI-based anode.}, } @article {pmid36690218, year = {2023}, author = {Dong, K and Qiu, Y and Wang, X and Yu, D and Yu, Z and Feng, J and Wang, J and Gu, R and Zhao, J}, title = {Towards low carbon demand and highly efficient nutrient removal: Establishing denitrifying phosphorus removal in a biofilm-based system.}, journal = {Bioresource technology}, volume = {372}, number = {}, pages = {128658}, doi = {10.1016/j.biortech.2023.128658}, pmid = {36690218}, issn = {1873-2976}, mesh = {*Sewage ; *Phosphorus ; Denitrification ; Nitrates ; Carbon ; Bioreactors ; Nitrogen ; Phosphates ; Organic Chemicals ; Nutrients ; Biofilms ; Waste Disposal, Fluid/methods ; }, abstract = {The combined denitrifying phosphorus removal (DPR) and Anammox process is expected to achieve advanced nutrient removal with low carbon consumption. However, exchanging ammonia/nitrate between them is one limitation. This study investigated the feasibility of conducting DPR in a biofilm reactor to solve that problem. After 46-day anaerobic/aerobic operation, high phosphorus removal efficiency (PRE, 83.15 %) was obtained in the activated sludge (AS) and biofilm co-existed system, in which the AS performed better. Phosphate-accumulating organisms might quickly adapt to the anoxic introduced nitrate, but the following aerobic stage ensured a low effluent orthophosphate (<1.03 mg/L). Because of waste sludge discharging and AS transforming to biofilm, the suspended solids dropped below 60 mg/L on Day 100, resulting in PRE decline (17.17 %) and effluent orthophosphate rise (4.23 mg/L). Metagenomes analysis revealed that Pseudomonas and Thiothrix had genes for denitrification and encoding Pit phosphate transporter, and Candidatus_Competibacter was necessary for biofilm formation.}, } @article {pmid36689842, year = {2023}, author = {Wang, W and Cao, Y and Li, J and Lu, S and Ge, H and Pan, S and Pan, X and Wang, L}, title = {The impact of osmotic stresses on the biofilm formation, immunodetection, and morphology of Aeromonas hydrophila.}, journal = {Microbiological research}, volume = {269}, number = {}, pages = {127301}, doi = {10.1016/j.micres.2023.127301}, pmid = {36689842}, issn = {1618-0623}, mesh = {Humans ; *Aeromonas hydrophila ; Osmotic Pressure ; *Sodium Chloride/metabolism ; Ammonia/metabolism ; Biofilms ; Sucrose/metabolism ; }, abstract = {Aeromonas hydrophila (Ah) is a zoonotic pathogen of great importance to aquaculture and human health. This study systematically evaluated the impact of salinity, sugar, ammonia nitrogen, and nitric nitrogen levels on the fitness of Ah by using Luria-Bertani (LB) broth supplemented with different concentrations of NaCl, sucrose, NH4Cl, urea, NaNO2 or NaNO3. Results showed that the static biofilm formation of Ah was higher at 28 °C compared to 37 °C (P < 0.05). At 28 °C, as the NaCl (>1 %) and sucrose levels increased, the Ah biofilm formation and the binding between Ah cells and monoclonal antibodies (mAbs, for immunodetection) decreased. Elevated ammonia nitrogen and nitric nitrogen levels generated no significant impact on Ah biofilm formation or immunodetection (P > 0.05). The expression of mAbs-targeted Omp remained unchanged under high NaCl or sucrose conditions. Further analysis showed that high sucrose conditions led to the over-expression of the extracellular polysaccharides (PS) and promoted the formation of capsule-like structures. These over-expressed PS and capsule structures might be one reason explaining the inhibited immunodetection efficacy. Results generated from this study provide crucial insights for the design of recovery and detection protocols for Ah present in food or environmental samples.}, } @article {pmid36688769, year = {2023}, author = {Lorenzini, M and Cappello, MS and Andreolli, M and Zapparoli, G}, title = {Characterization of selected species of Pichia and Candida for their growth capacity in apple and grape must and their biofilm parameters.}, journal = {Letters in applied microbiology}, volume = {76}, number = {1}, pages = {}, doi = {10.1093/lambio/ovac028}, pmid = {36688769}, issn = {1472-765X}, mesh = {Pichia/metabolism ; Candida/metabolism ; *Vitis/metabolism ; *Malus ; Yeasts/metabolism ; *Wine/analysis ; Fermentation ; }, abstract = {Pichia and Candida species include biofilm-forming yeasts able to spoil foods and beverages. Strains belonging to 10 Pichia and Candida species isolated from apples, grape musts, and wines were analysed. They were subjected to molecular typing and characterized for their ability to grow and ferment must for cider and wine production, and for their biofilm properties. All strains grew similarly in apple and grape must. Glucose-fermenting strains displayed differentiated fermentation performances. Great variation in SO2 and ethanol sensitivity was observed among the strains. Pichia manshurica strains showed high tolerance to both molecules. Eleven and five surface-spreading biofilm (MAT) phenotypes were identified in solid and liquid media, respectively. Strains produced biofilms with variable thicknesses and widths in culture tubes. Cell adherence and aqueous-hydrocarbon biphasic hydrophobicity assays were carried out. Some Pichia manshurica and P. membranifaciens strains exhibited a high capacity to form a thick biofilm and had high cell adherence and hydrophobicity values. These strains could be more likely to colonize the internal surfaces of tanks. This study evidenced that some Pichia and Candida strains can proliferate during apple and grape must fermentation and may be detrimental the beverage quality, due to their specific biofilm properties.}, } @article {pmid36688748, year = {2023}, author = {Fernandes, MSM and Rios, JC and Vasconcelos, BM and Lourenço, MLMC and Matos, MNC and Cavalcante, RMB and de Almeida, MVA and Costa, RA and Carneiro, VA}, title = {Effect of Lactobacillus spp. cell-free supernatant against planktonic growth and biofilm formation of foodborne Escherichia coli isolates.}, journal = {Letters in applied microbiology}, volume = {76}, number = {1}, pages = {}, doi = {10.1093/lambio/ovac006}, pmid = {36688748}, issn = {1472-765X}, support = {//Federal University of Ceará/ ; }, mesh = {Animals ; *Escherichia coli ; Lactobacillus ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The aim of this work was to evaluate the anti-Escherichia coli effect of cell-free supernatant (CFS) of Lactobacillus spp. against planktonic and biofilm forms of foodborne isolates. Escherichiacoli strains (P12, P25, P35 and P36), previously isolated from fresh filets of fish, were subjected to antimicrobial susceptibility determination by the disc-diffusion agar method. Subsequently, the antagonistic effect between probiotic and pathogenic strains was determined by spot overlay assay. Finally, the CFS activity against pre-established (12 h) biofilms was demonstrated through biomass quantification by crystal violet staining and scanning electron microscopy (SEM). All isolates presented some pattern of resistance, primarily to ampicillin and tetracycline. Probiotic strains presented high antagonistic effects against all E. coli strains, presenting inhibition zones (R) ranging from 15.60 to 20.67 mm. Additionally, the residual biomass of pre-established (12 h) biofilm was drastically reduced about 50% after CFS treatment (P < 0.01). What can be noted by SEM images, which show less surface-attached cells of CFS-treated biofilms of E. coli (P12). Thus, cell-free preparations produced from Lactobacillus spp. may represent a tool in the battle against planktonic cells and biofilm forms of antibiotic-resistant E. coli.}, } @article {pmid36688105, year = {2023}, author = {Kumar, S and Nguyen, AT and Goswami, S and Ferracane, J and Koley, D}, title = {Real-Time Monitoring of Biofilm Formation Using a Noninvasive Impedance-Based Method.}, journal = {Sensors and actuators. B, Chemical}, volume = {376}, number = {Pt A}, pages = {}, pmid = {36688105}, issn = {0925-4005}, support = {R01 DE027999/DE/NIDCR NIH HHS/United States ; }, abstract = {Biofilms are complex three-dimensional microbial communities that adhere to a variety of surfaces and interact with their surroundings. Because of the dynamic nature of biofilm formation, establishing a uniform technique for quantifying and monitoring biofilm volume, shape, and features in real-time is challenging. Herein, we describe a noninvasive electrochemical impedance approach for real-time monitoring of dental plaque-derived multispecies biofilm growth on a range of substrates. A working equation relating electrochemical impedance to live biofilm volume has been developed that is applicable to all three surfaces examined, including glass, dental filling resin, and Ca[2+]-releasing resin composites. Impedance changes of 2.5, 35, 50, and 65% correlated to biofilm volumes of 0.10 ± 0.01, 16.9 ± 2.2, 29.7 ± 2.3, and 38.6 ± 2.8 μm[3]/μm[2], respectively. We discovered that glass, dental filling resin, and Ca[2+]-releasing dental composites required approximately 3.5, 4.5, and 6 days, respectively, to achieve a 50% change in impedance. The local pH change at the biofilm-substrate interfaces also monitored with potentiometry pH microsensor, and pH change varied according to biofilm volume. This impedance-based technique can be a useful analytical method for monitoring the growth of biofilms on a variety of substrates in real-time. Therefore, this technique may be beneficial for examining antibacterial properties of novel biomaterials.}, } @article {pmid36687621, year = {2022}, author = {Li, X and Gu, N and Ye, Y and Lan, H and Peng, F and Peng, G}, title = {Intense pulsed light for inactivating planktonic and biofilm molds in food.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1104875}, pmid = {36687621}, issn = {1664-302X}, abstract = {It has been reported that about a quarter of the world's agriculture products is unable to be consumed each year because of mold contamination, resulting in incalculable economic losses. Despite modern food technology and the various preservation techniques available, the problem of mold contamination of food is still not adequately controlled. In this study, we simulated the biofilm formed by Aspergillus niger and Penicillium glaucum in liquid and solid food in 96 well cell culture plates and polycarbonate membrane models, respectively, and investigated the fungicidal effect of IPL on planktonic and biofilm molds at three different capacitance parameters at room and refrigerator temperatures. The results show that IPL can achieve fungicidal rates of over 99% for planktonic molds and over 90% for biofilm molds, and that the smaller the capacitance, the more frequent the irradiation required to achieve the same fungicidal rate. In addition, temperature, A. niger or Penicillium glaucum have no effect on the fungicidal effect of IPL. We believe that IPL is a promising non-thermal physical sterilization technique for fungal inhibition on food surfaces.}, } @article {pmid36687584, year = {2022}, author = {Bisht, K and Luecke, AR and Wakeman, CA}, title = {Temperature-specific adaptations and genetic requirements in a biofilm formed by Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1032520}, pmid = {36687584}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a gram-negative opportunistic pathogen often associated with nosocomial infections that are made more severe by this bacterium's ability to form robust biofilms. A biofilm is a microbial community encompassing cells embedded within an extracellular polymeric substrate (EPS) matrix that is typically secreted by the encased microbial cells. Biofilm formation is influenced by several environmental cues, and temperature fluctuations are likely to be an important stimulus in the lifecycle of P. aeruginosa as it transitions between life in aquatic or soil environments to sites of infection in the human host. Previous work has demonstrated that human body temperature can induce a shift in the biofilm EPS relative to room temperature growth, resulting in an incorporation of a filamentous phage coat protein into the biofilm EPS. In this study, we sought to identify adaptations enabling biofilm formation at room temperature or temperatures mimicking the natural environment of P. aeruginosa (23°C and 30°C) relative to temperatures mimicking life in the human host (37°C and 40°C). We identified higher biofilm: biomass ratios at lower temperatures on certain substrates, which correlated with a higher relative abundance of apparent polysaccharide EPS content. However, the known genes for EPS polysaccharide production in P. aeruginosa PA14 did not appear to be specifically important for temperature-dependent biofilm adaptation, with the pelB gene appearing to be generally important and the algD gene being generally expendable in all conditions tested. Instead, we were able to identify two previously uncharacterized hypothetical proteins (PA14_50070 and PA14_67550) specifically required for biofilm formation at 23°C and/or 30°C relative to temperatures associated with the human host. These unstudied contributors to biofilm integrity may have been previously overlooked since most P. aeruginosa biofilm studies tend to use 37°C growth temperatures. Overall, our study demonstrates that temperature shifts can have dramatic impacts on biofilm structure and highlights the importance of studying environment-specific adaptations in biofilm physiology.}, } @article {pmid36687169, year = {2023}, author = {Yamaguchi-Kuroda, Y and Kikuchi, Y and Kokubu, E and Ishihara, K}, title = {Porphyromonas gingivalis diffusible signaling molecules enhance Fusobacterium nucleatum biofilm formation via gene expression modulation.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2165001}, pmid = {36687169}, issn = {2000-2297}, abstract = {BACKGROUND: Periodontitis is caused by a dysbiotic shift in the dental plaque microbiome. Fusobacterium nucleatum is involved in the colonization of Porphyromonas gingivalis, which plays a key role in dysbiosis, via coaggregation and synergy with this microorganism.

AIM: We investigated the effect of diffusible signaling molecules from P. gingivalis ATCC 33277 on F. nucleatum TDC 100 to elucidate the synergistic mechanisms involved in dysbiosis.

METHODS: The two species were cocultured separated with an 0.4-µm membrane in tryptic soy broth, and F. nucleatum gene expression profiles in coculture with P. gingivalis were compared with those in monoculture.

RESULTS: RNA sequencing revealed 139 genes differentially expressed between the coculture and monoculture. The expression of 52 genes was upregulated, including the coaggregation ligand-coding gene. Eighty-seven genes were downregulated. Gene Ontology analysis indicated enrichment for the glycogen synthesis pathway and a decrease in de novo synthesis of purine and pyrimidine.

CONCLUSION: These results indicate that diffusible signaling molecules from P. gingivalis induce metabolic changes in F. nucleatum, including an increase in polysaccharide synthesis and reduction in de novo synthesis of purine and pyrimidine. The metabolic changes may accelerate biofilm formation by F. nucleatum with P. gingivalis. Further, the alterations may represent potential therapeutic targets for preventing dysbiosis.}, } @article {pmid36685419, year = {2023}, author = {Tiwari, M and Panwar, S and Tiwari, V}, title = {Assessment of potassium ion channel during electric signalling in biofilm formation of Acinetobacter baumannii for finding antibiofilm molecule.}, journal = {Heliyon}, volume = {9}, number = {1}, pages = {e12837}, pmid = {36685419}, issn = {2405-8440}, abstract = {Acinetobacter baumannii is an opportunistic ESKAPE pathogen which causes nosocomial infections and can produce biofilms that act as resistant determinants. The role of quorum sensing (chemical signaling) in biofilm establishment has already been studied extensively, but the existence of electrochemical signaling during biofilm formation by A. baumannii has not yet been investigated. The current study evaluated the presence of electrical signaling, types of ion channels involved, and their role in biofilm formation using spectroscopic and microbiological methods. The findings suggest that the potassium ion channel has a significant role in the electrical signaling during the biofilm formation by A. baumannii. Further, in-silico screening, molecular mechanics, and molecular dynamic simulation studies identify a potential lead, ZINC12496555(a specific inhibitor), which targets the potassium ion channel protein of A. baumannii. Mutational analysis of the interacting residues showed alterations in the unfolding rate of this protein after the selected mutation, which shows its role in the stability of this protein. It was also observed that identified lead has high antibiofilm activity, no human off-targets, and non-cytotoxicity to cell lines. Thus, identified lead against the potassium channel of A baumannii may be used as an effective therapeutic for the treatment of A. baumannii infections after further experimental validation.}, } @article {pmid36681348, year = {2023}, author = {Paniguel Oliveira, E and Giordani, A and Kawanishi, J and Syrto Octavio de Souza, T and Okada, DY and Brucha, G and Brito de Moura, R}, title = {Biofilm stratification and autotrophic-heterotrophic interactions in a structured bed reactor (SBRIA) for carbon and nitrogen removal.}, journal = {Bioresource technology}, volume = {372}, number = {}, pages = {128639}, doi = {10.1016/j.biortech.2023.128639}, pmid = {36681348}, issn = {1873-2976}, mesh = {*Denitrification ; *Nitrogen/metabolism ; Nitrification ; Carbon ; RNA, Ribosomal, 16S/genetics ; Bioreactors/microbiology ; Biofilms ; Sewage ; }, abstract = {The structured-bed reactor with intermittent aeration (SBRIA) is a promising technology for simultaneous carbon and nitrogen removal from wastewater. An in depth understanding of the microbiological in the reactor is crucial for its optimization. In this research, biofilm samples from the aerobic and anoxic zones of an SBRIA were analyzed through 16S rRNA sequencing to evaluate the bacterial community shift with variations in the airflow and aeration time. The control of the airflow and aeration time were essential to guarantee reactor performances to nitrogen removal close to 80%, as it interfered in nitrifying and denitrifying communities. The aeration time of 1.75 h led to establishment of different nitrogen removal pathways by syntrophic relationships between nitrifier, denitrifier and anammox species. Additionally, the predominance of these different species in the internal and external parts of the biofilm varied according to the airflow.}, } @article {pmid36681347, year = {2023}, author = {Saidulu, D and Srivastava, A and Gupta, AK}, title = {Elucidating the performance of integrated anoxic/oxic moving bed biofilm reactor: Assessment of organics and nutrients removal and optimization using feed forward back propagation neural network.}, journal = {Bioresource technology}, volume = {371}, number = {}, pages = {128641}, doi = {10.1016/j.biortech.2023.128641}, pmid = {36681347}, issn = {1873-2976}, mesh = {*Wastewater ; *Waste Disposal, Fluid ; Biofilms ; Bioreactors ; Nitrogen/analysis ; Waste Products ; Neural Networks, Computer ; Denitrification ; }, abstract = {A lab-scale integrated anoxic and oxic (A/O) moving bed biofilm reactor (MBBR) was investigated for the removal of organics and nutrients by varying chemical oxygen demand (COD) to NH4-N ratio (C/N ratio: 3.5, 6.75, and 10), hydraulic retention time (HRT: 6 h, 15 h, and 24 h), and recirculation ratio (R: 1, 2, and 3). The use of activated carbon coated carriers prepared from waste polyethylene material and polyurethane sponges attached to a cylindrical frame in the integrated A/O MBBR increased the attached growth biomass significantly. >95 % of COD removal was observed under the C/N ratio of 10 at an HRT of 24 h. While the low C/N ratio favored the removal of NH4-N (∼98 %) and PO4[3-]-P (∼90 %) with an optimal R of 1.75. Using the experimental dataset, to predict and forecast the performance of integrated A/O MBBR, a feed-forward-backpropagation-neural-network model was developed.}, } @article {pmid36679198, year = {2023}, author = {Zhang, Y and Ge, T and Li, Y and Lu, J and Du, H and Yan, L and Tan, H and Li, J and Yin, Y}, title = {Anti-Fouling and Anti-Biofilm Performance of Self-Polishing Waterborne Polyurethane with Gemini Quaternary Ammonium Salts.}, journal = {Polymers}, volume = {15}, number = {2}, pages = {}, pmid = {36679198}, issn = {2073-4360}, abstract = {Biofilms are known to be difficult to eradicate and control, complicating human infections and marine biofouling. In this study, self-polishing and anti-fouling waterborne polyurethane coatings synthesized from gemini quaternary ammonium salts (GQAS), polyethylene glycol (PEG), and polycaprolactone diol (PCL) demonstrate excellent antibiofilm efficacy. Their anti-fouling and anti-biofilm performance was confirmed by a culture-based method in broth media, with the biofilm formation factor against Gram-positive (S. aureus) and Gram-negative bacterial strains (E. coli) for 2 days. The results indicate that polyurethane coatings have excellent anti-biofilm activity when the content of GQAS reached 8.5 wt% against S. aureus, and 15.8 wt% against E. coli. The resulting waterborne polyurethane coatings demonstrate both hydrolytic and enzymatic degradation, and the surface erosion enzymatic degradation mechanism enables them with good self-polishing capability. The extracts cyto-toxicity of these polyurethane coatings and degradation liquids was also systematically studied; they could be degraded to non-toxic or low toxic compositions. This study shows the possibility to achieve potent self-polishing and anti-biofilm efficacy by integrating antibacterial GQAS, PEG, and PCL into waterborne polyurethane coatings.}, } @article {pmid36678928, year = {2023}, author = {Arenas-Vivo, A and Celis Arias, V and Amariei, G and Rosal, R and Izquierdo-Barba, I and Hidalgo, T and Vallet-Regí, M and Beltrán, HI and Loera-Serna, S and Horcajada, P}, title = {Antiadherent AgBDC Metal-Organic Framework Coating for Escherichia coli Biofilm Inhibition.}, journal = {Pharmaceutics}, volume = {15}, number = {1}, pages = {}, pmid = {36678928}, issn = {1999-4923}, support = {PID2019-104228RB-I00//MCIN/ AEI /10.13039/501100011033/ ; FEDER 2014-2020-OE REACT-UE 1//VIRMOF-CM project associated with R&D projects in response to COVID-19 from "Comunidad de Madrid" and European Regional Development Fund-FEDER 2014-2020-OE REACT-UE 1/ ; MICIU, RED2018-102471-T//Multifunctional Metallodrugs in Diagnosis and Therapy Network/ ; No 897678//European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement/ ; A1-S-31186 and 243224//Basic Sciences SEP-CONACyT funding/ ; Nº agreement 660046//CONACyT scholarship/ ; No. 694160//European Research Council (Advanced Grant VERDI; ERC-2015-AdG Proposal)/ ; }, abstract = {Surface microbial colonization and its potential biofilm formation are currently a major unsolved problem, causing almost 75% of human infectious diseases. Pathogenic biofilms are capable of surviving high antibiotic doses, resulting in inefficient treatments and, subsequently, raised infection prevalence rates. Antibacterial coatings have become a promising strategy against the biofilm formation in biomedical devices due to their biocidal activity without compromising the bulk material. Here, we propose for the first time a silver-based metal-organic framework (MOF; here denoted AgBDC) showing original antifouling properties able to suppress not only the initial bacterial adhesion, but also the potential surface contamination. Firstly, the AgBDC stability (colloidal, structural and chemical) was confirmed under bacteria culture conditions by using agar diffusion and colony counting assays, evidencing its biocide effect against the challenging E. coli, one of the main representative indicators of Gram-negative resistance bacteria. Then, this material was shaped as homogeneous spin-coated AgBDC thin film, investigating its antifouling and biocide features using a combination of complementary procedures such as colony counting, optical density or confocal scanning microscopy, which allowed to visualize for the first time the biofilm impact generated by MOFs via a specific fluorochrome, calcofluor.}, } @article {pmid36678466, year = {2023}, author = {Khalid, A and Cookson, AR and Whitworth, DE and Beeton, ML and Robins, LI and Maddocks, SE}, title = {A Synthetic Polymicrobial Community Biofilm Model Demonstrates Spatial Partitioning, Tolerance to Antimicrobial Treatment, Reduced Metabolism, and Small Colony Variants Typical of Chronic Wound Biofilms.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36678466}, issn = {2076-0817}, abstract = {Understanding chronic wound infection is key for successful treatment and requires accurate laboratory models. We describe a modified biofilm flow device that effectively mimics the chronic wound environment, including simulated wound fluid, a collagen-based 3D biofilm matrix, and a five-species mixture of clinically relevant bacteria (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Citrobacter freundii). Mixed biofilms were cultured for between 3 and 14 days with consistent numbers of bacteria that exhibited reduced metabolic activity, which increased with a high dose of glucose. S. aureus was recovered from biofilms as a small colony variant, but as a normal colony variant if P. aeruginosa was excluded from the system. Bacteria within the biofilm did not co-aggregate but formed discrete, species-specific clusters. Biofilms demonstrated differential tolerance to the topical antimicrobials Neosporin and HOCl, consistent with protection due to the biofilm lifestyle. The characteristics exhibited within this model match those of real-world wound biofilms, reflecting the clinical scenario and yielding a powerful in vitro tool that is versatile, inexpensive, and pivotal for understanding chronic wound infection.}, } @article {pmid36678381, year = {2022}, author = {Khalil, MA and Alorabi, JA and Al-Otaibi, LM and Ali, SS and Elsilk, SE}, title = {Antibiotic Resistance and Biofilm Formation in Enterococcus spp. Isolated from Urinary Tract Infections.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36678381}, issn = {2076-0817}, support = {TURSP-2020/95//Taif University/ ; }, abstract = {Background: A urinary tract infection (UTI) resulting from multidrug-resistant (MDR) enterococci is a common disease with few therapeutic options. About 15% of urinary tract infections are caused by biofilm-producing Enterococcus spp. Therefore, the objective of this study was to identify the MDR enterococci associated with UTIs and assess their potential to produce biofilms. Methods: Thirty Enterococcus isolates were obtained from urine samples collected from UTI patients at King Abdulaziz Specialist Hospital in Taif, Saudi Arabia. The antimicrobial resistance profiles of the isolates were evaluated using disk diffusion techniques against 15 antimicrobial agents. Two techniques, Congo red agar (CRA) and a microtiter plate (MTP), were used to assess the potential of the isolates to produce biofilms. The enterococcal isolates were screened for biofilm-related genes, esp; ebpA; and ebpB, using the PCR method. Results: The molecular identification of the collected bacteria revealed the presence of 73.3% Enterococcus faecalis and 26.6% Enterococcus faecium. The antibiotic susceptibility test revealed that all the tested Enterococcus spp. were resistant to all antimicrobials except for linezolid and tigecycline. Additionally, by employing the CRA and MTP techniques, 76.6% and 100% of the Enterococcus isolates were able to generate biofilms, respectively. In terms of the association between the antibiotic resistance and biofilm’s formation, it was observed that isolates capable of creating strong biofilms were extremely resistant to most of the antibiotics tested. The obtained data showed that all the tested isolates had biofilm-encoding genes. Conclusions: Our research revealed that the biofilm-producing enterococci bacteria that causes urinary tract infections were resistant to antibiotics. Therefore, it is necessary to seek other pharmacological treatments if antibiotic medicine fails.}, } @article {pmid36678375, year = {2022}, author = {Sulaiman, R and Trizna, E and Kolesnikova, A and Khabibrakhmanova, A and Kurbangalieva, A and Bogachev, M and Kayumov, A}, title = {Antimicrobial and Biofilm-Preventing Activity of l-Borneol Possessing 2(5H)-Furanone Derivative F131 against S. aureus—C. albicans Mixed Cultures.}, journal = {Pathogens (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36678375}, issn = {2076-0817}, support = {FZSM-2022-0017//Ministry of Science and higher Education of Russian Federation/ ; 0671-2020-0063//Ministry of Science and higher Education of Russian Federation/ ; }, abstract = {Candida albicans and Staphylococcus aureus are human pathogens that are able to form mixed biofilms on the surface of mucous membranes, implants and catheters. In biofilms, these pathogens have increased resistance to antimicrobials, leading to extreme difficulties in the treatment of mixed infections. The growing frequency of mixed infections caused by S. aureus and C. albicans requires either the development of new antimicrobials or the proposal of alternative approaches to increase the efficiency of conventional ones. Here, we show the antimicrobial, biofilm-preventing and biofilm-eradicating activity of 2(5H)-furanone derivative F131, containing an l-borneol fragment against S. aureus-C. albicans mixed biofilms. Furanone F131 is also capable of inhibiting the formation of monospecies and mixed biofilms by S. aureus and C. albicans. The minimal biofilm-prevention concentration (MBPC) of this compound was 8-16 μg/mL for S. aureus and C. albicans mono- and two-species biofilms. While the compound demonstrates slightly lower activity compared to conventional antimicrobials (gentamicin, amikacin, fluconazole, terbinafine and benzalkonium chloride), F131 also increases the antimicrobial activity of fluconazole-gentamicin and benzalkonium chloride against mixed biofilms of S. aureus-C. albicans, thus reducing MBPC of fluconazole-gentamicin by 4-16 times and benzalkonium chloride twofold. F131 does not affect the transcription of the MDR1, CDR1 and CDR2 genes, thus suggesting a low risk of micromycete resistance to this compound. Altogether, combined use of antibiotics with a F131 could be a promising option to reduce the concentration of fluconazole used in antiseptic compositions and reduce the toxic effect of benzalkonium chloride and gentamicin. This makes them an attractive starting point for the development of alternative antimicrobials for the treatment of skin infections caused by S. aureus-C. albicans mixed biofilms.}, } @article {pmid36677463, year = {2023}, author = {Smitran, A and Lukovic, B and Bozic, L and Jelic, D and Jovicevic, M and Kabic, J and Kekic, D and Ranin, J and Opavski, N and Gajic, I}, title = {Carbapenem-Resistant Acinetobacter baumannii: Biofilm-Associated Genes, Biofilm-Eradication Potential of Disinfectants, and Biofilm-Inhibitory Effects of Selenium Nanoparticles.}, journal = {Microorganisms}, volume = {11}, number = {1}, pages = {}, pmid = {36677463}, issn = {2076-2607}, support = {IN-DEPTH, Grant No. 6059147//Science Fund of the Republic of Serbia/ ; }, abstract = {This study aimed to investigate the biofilm-production ability of carbapenem-resistant Acinetobacter baumannii (CRAB), the biofilm-eradication potential of 70% ethanol and 0.5% sodium hypochlorite, the effects of selenium nanoparticles (SeNPs) against planktonic and biofilm-embedded CRAB, and the relationship between biofilm production and bacterial genotypes. A total of 111 CRAB isolates were tested for antimicrobial susceptibility, biofilm formation, presence of the genes encoding carbapenemases, and biofilm-associated virulence factors. The antibiofilm effects of disinfectants and SeNPs against CRAB isolates were also tested. The vast majority of the tested isolates were biofilm producers (91.9%). The bap, ompA, and csuE genes were found in 57%, 70%, and 76% of the CRAB isolates, with the csuE being significantly more common among biofilm producers (78.6%) compared to non-biofilm-producing CRAB (25%). The tested disinfectants showed a better antibiofilm effect on moderate and strong biofilm producers than on weak producers (p < 0.01). The SeNPs showed an inhibitory effect against all tested planktonic (MIC range: 0.00015 to >1.25 mg/mL) and biofilm-embedded CRAB, with a minimum biofilm inhibitory concentration of less than 0.15 mg/mL for 90% of biofilm producers. In conclusion, SeNPs might be used as promising therapeutic and medical device coating agents, thus serving as an alternative approach for the prevention of biofilm-related infections.}, } @article {pmid36677395, year = {2022}, author = {AboElmaaty, SA and Shati, AA and Alfaifi, MY and Elbehairi, SEI and Sheraba, NS and Hassan, MG and Badawy, MSEM and Ghareeb, A and Hamed, AA and Gabr, EZ}, title = {Biofilm Inhibitory Activity of Actinomycete-Synthesized AgNPs with Low Cytotoxic Effect: Experimental and In Silico Study.}, journal = {Microorganisms}, volume = {11}, number = {1}, pages = {}, pmid = {36677395}, issn = {2076-2607}, abstract = {The emergence of resistance by biofilm-forming bacteria has reached alarming and dangerous levels that threaten human civilization. The current study sought to investigate the antibiofilm potential of green-synthesized silver nanoparticles, mediated by a new Streptomyces strain. Zeta potential, transmission electron microscopy (TEM), and UV-Vis spectroscopy were used to analyze the biosynthesized AgNPs. Results revealed that silver nanoparticles had a size of (5.55 and 45.00 nm) nm and a spherical shape, with surface plasmon resonance (SPR) absorption at 400-460 nm in the UV-vis spectra establishing the formation of Streptomyces-Ag-NPs. The biosynthesized AgNPs showed a pronounced antibacterial efficacy against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. Moreover, the obtained Streptomyces-AgNPs exerted biofilm inhibition activity against nosocomial hospital-resistant bacteria, including Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The mechanism of biogenic AgNPs antibacterial action was visualized using TEM, which indicated the AgNPs accumulation and disruption of bacterial cell membrane function. Additionally, a molecular docking study was conducted to evaluate the binding mode of AgNPs with an Escherichia coli outer membrane. Furthermore, the cytotoxic profile of the AgNPs was evaluated toward three cell lines (MCF-7, HepG2 & HCT 116), and the low cytotoxic effects of the obtained nanoparticles indicated their possible medical application with low risks to human health.}, } @article {pmid36677381, year = {2022}, author = {Chi, SI and Ramirez-Arcos, S}, title = {Staphylococcal Enterotoxins Enhance Biofilm Formation by Staphylococcus aureus in Platelet Concentrates.}, journal = {Microorganisms}, volume = {11}, number = {1}, pages = {}, pmid = {36677381}, issn = {2076-2607}, support = {IG2019-SR//Canadian Blood Services/ ; }, abstract = {Biofilm formation and slow growth by Staphylococcus aureus in platelet concentrates (PCs) cause missed detection of this bacterium during routine PC screening with automated culture systems. This heightens the chances of false-negative screening transfusions and pre-disposes transfusion patients to an elevated risk of sepsis due to secretion of staphylococcal enterotoxins (SEs) in PCs. A hybrid approach of comparative RNAseq analyses and CRISPR mutagenesis of SE genes was employed to investigate the effect of SEs in S. aureus growth and biofilm formation in PCs. RNAseq data showed no differential expression for key biofilm genes, whereas SE genes were upregulated (>0.5- to 3.6-fold change) in PCs compared to trypticase soy broth (TSB). Remarkably, growth and biofilm formation assays revealed increased growth for the S. aureus SE mutants, while their ability to form biofilms was significantly impaired (−6.8- to −2.4-fold change) in comparison to the wild type strain, in both PCs and TSB. Through the well-established superantigen mechanism of SEs, we propose three roles for SEs during biofilm development in PCs: (1) provide a scaffold for biofilm matrix, (2) mediate cell-to-cell aggregation, and (3) guarantee biofilm survival. Furthermore, SE contribution to both growth and biofilm development seems to be centrally regulated by agr via quorum sensing and by saeSR and sigB. This study reveals new roles for SEs, which enforce their relevance in ensuring PC safety for transfusion patients. It further deciphers the underlying reasons for failed S. aureus detection in PCs during screening with automated culture systems.}, } @article {pmid36676844, year = {2022}, author = {Abdulgader, M and Yu, J and Zinatizadeh, AA and Williams, P and Rahimi, Z}, title = {Effect of Different Operational Conditions on the Treatment Performance of Milk Processing Wastewater (MPW) Using a Single Stage Flexible Fibre Biofilm Reactor (SS-FFBR).}, journal = {Membranes}, volume = {13}, number = {1}, pages = {}, pmid = {36676844}, issn = {2077-0375}, abstract = {The performance of a biofilm system, single-stage flexible fibre biofilm reactor (SS-FFBR) treating milk processing wastewater (MPW) is evaluated under various process and operational conditions. The system behavior is analyzed with different biological and physical parameters. Results show that the high COD removal efficiency of 95% is obtained at a low CODin concentration of 809 mg/L. However, the COD removal is slightly decreased to 91.7% once the CODin concentration incremented to nearly 4000 mg/L. The effect of organic loading rate (OLR) on the SS-FFBR performance is examined as total suspended solids removal efficiency, dissolved oxygen, and turbidity. The SS-FFBR showed considerable performance, so that 89.9% and 89.7% removal efficiencies in terms of COD and TSS removals, respectively, obtained at the highest OLR of 11.7 kg COD/m[3]d. TSS removal efficiency of 96.7% is obtained at a low OLR of 1.145 kg COD/m[3]d. A linear relationship between the OLR and COD removal rate was revealed. The COD removal rate was incremented from 1.08 to 10.68 kg COD/m[3]d as the OLR increased from 1.145 to 11.7 kg COD/m[3]d. Finally, the operating system is a promising technique recommended to treat various industrial wastewaters with high OLR.}, } @article {pmid36676823, year = {2022}, author = {Alharthi, MS and Bamaga, O and Abulkhair, H and Organji, H and Shaiban, A and Macedonio, F and Criscuoli, A and Drioli, E and Wang, Z and Cui, Z and Jin, W and Albeirutty, M}, title = {Evaluation of a Hybrid Moving Bed Biofilm Membrane Bioreactor and a Direct Contact Membrane Distillation System for Purification of Industrial Wastewater.}, journal = {Membranes}, volume = {13}, number = {1}, pages = {}, pmid = {36676823}, issn = {2077-0375}, support = {632//Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia/ ; }, abstract = {Integrated wastewater treatment processes are accepted as the best option for sustainable and unrestricted onsite water reuse. In this study, moving bed biofilm reactor (MBBR), membrane bioreactor (MBR), and direct contact membrane distillation (DCMD) treatment steps were integrated successively to obtain the combined advantages of these processes for industrial wastewater treatment. The MBBR step acts as the first step in the biological treatment and also mitigates foulant load on the MBR. Similarly, MBR acts as the second step in the biological treatment and serves as a pretreatment prior to the DCMD step. The latter acts as a final treatment to produce high-quality water. A laboratory scale integrated MBBR/MBR/DCMD experimental system was used for assessing the treatment efficiency of primary treated (PTIWW) and secondary treated (STIWW) industrial wastewater in terms of permeate water flux, effluent quality, and membrane fouling. The removal efficiency of total dissolved solids (TDS) and effluent permeate flux of the three-step process (MBBR/MBR/DCMD) were better than the two-step (MBR/DCMD) process. In the three-step process, the average removal efficiency of TDS was 99.85% and 98.16% when treating STIWW and PTIWW, respectively. While in the case of the two-step process, the average removal efficiency of TDS was 93.83% when treating STIWW. Similar trends were observed for effluent permeate flux values which were found, in the case of the three-step process, 62.6% higher than the two-step process, when treating STIWW in both cases. Moreover, the comparison of the quality of the effluents obtained with the analysed configurations with that obtained by Jeddah Industrial Wastewater Treatment Plant proved the higher performance of the proposed membrane processes.}, } @article {pmid36676121, year = {2023}, author = {Mishra, S and Gupta, A and Upadhye, V and Singh, SC and Sinha, RP and Häder, DP}, title = {Therapeutic Strategies against Biofilm Infections.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, pmid = {36676121}, issn = {2075-1729}, abstract = {A biofilm is an aggregation of surface-associated microbial cells that is confined in an extracellular polymeric substance (EPS) matrix. Infections caused by microbes that form biofilms are linked to a variety of animals, including insects and humans. Antibiotics and other antimicrobials can be used to remove or eradicate biofilms in order to treat infections. However, due to biofilm resistance to antibiotics and antimicrobials, clinical observations and experimental research clearly demonstrates that antibiotic and antimicrobial therapies alone are frequently insufficient to completely eradicate biofilm infections. Therefore, it becomes crucial and urgent for clinicians to properly treat biofilm infections with currently available antimicrobials and analyze the results. Numerous biofilm-fighting strategies have been developed as a result of advancements in nanoparticle synthesis with an emphasis on metal oxide np. This review focuses on several therapeutic strategies that are currently being used and also those that could be developed in the future. These strategies aim to address important structural and functional aspects of microbial biofilms as well as biofilms' mechanisms for drug resistance, including the EPS matrix, quorum sensing (QS), and dormant cell targeting. The NPs have demonstrated significant efficacy against bacterial biofilms in a variety of bacterial species. To overcome resistance, treatments such as nanotechnology, quorum sensing, and photodynamic therapy could be used.}, } @article {pmid36676100, year = {2023}, author = {Lila, ASA and Rajab, AAH and Abdallah, MH and Rizvi, SMD and Moin, A and Khafagy, ES and Tabrez, S and Hegazy, WAH}, title = {Biofilm Lifestyle in Recurrent Urinary Tract Infections.}, journal = {Life (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, pmid = {36676100}, issn = {2075-1729}, abstract = {Urinary tract infections (UTIs) represent one of the most common infections that are frequently encountered in health care facilities. One of the main mechanisms used by bacteria that allows them to survive hostile environments is biofilm formation. Biofilms are closed bacterial communities that offer protection and safe hiding, allowing bacteria to evade host defenses and hide from the reach of antibiotics. Inside biofilm communities, bacteria show an increased rate of horizontal gene transfer and exchange of resistance and virulence genes. Additionally, bacterial communication within the biofilm allows them to orchestrate the expression of virulence genes, which further cements the infestation and increases the invasiveness of the infection. These facts stress the necessity of continuously updating our information and understanding of the etiology, pathogenesis, and eradication methods of this growing public health concern. This review seeks to understand the role of biofilm formation in recurrent urinary tact infections by outlining the mechanisms underlying biofilm formation in different uropathogens, in addition to shedding light on some biofilm eradication strategies.}, } @article {pmid36675932, year = {2023}, author = {Dias, LM and Klein, MI and Ferrisse, TM and Medeiros, KS and Jordão, CC and Bellini, A and Pavarina, AC}, title = {The Effect of Sub-Lethal Successive Applications of Photodynamic Therapy on Candida albicans Biofilm Depends on the Photosensitizer.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {36675932}, issn = {2309-608X}, support = {#2013/07276-1; 2018/14874-6; #2021/01191-0; #2019/27634-6//São Paulo Research Foundation/ ; #PIBIC46891; #PIBIC52686; #PIBIC51150//National Council for Scientific and Technological Development/ ; }, abstract = {This study aimed to evaluate the potential of successive applications of sub-lethal doses of the antimicrobial photodynamic therapy (aPDT) mediated by Photodithazine[®] (PDZ) and curcumin (CUR) associated with LED in the viability, reactive oxygen species (ROS) production, and gene expression of Candida albicans. The microbial assays were performed using planktonic cultures and biofilms. Ten successive applications (Apl#) were performed: aPDT (P+L+; C+L+), photosensitizer (P+L-; C+L-), and LED (P-L+; C-L+). Control groups were used (P-L-; C-L-). The viability of C. albicans was determined by cultivating treated cultures on agar plates with or without fluconazole (FLU). In addition, the ROS detection and expression of SOD1, CAP1, and ERG11 genes were determined. For planktonic cultures, no viable colonies were observed after Apl#3 (without FLU) and Apl#2 (with FLU) for either photosensitizer. Biofilm treated with P+L+ resulted in the absence of cell viability after Apl#7, while C+L+ showed ~1.40 log10 increase in cell viability after Apl#2, regardless of FLU. For both photosensitizers, after the last application with viable colonies, the production of ROS was higher in the biofilms than in the planktonic cultures, and SOD1 expression was the highest in P+L+. A reduction of CAP1 and ERG11 expression occurred after P+L+, regardless of FLU. C+L+ had a higher level of ROS, and the treatments were non-significant for gene expression. Sub-lethal doses of aPDT mediated by CUR could induce C. albicans resistance in biofilms, while C. albicans cells in biofilms were susceptible to aPDT mediated by PDZ.}, } @article {pmid36675919, year = {2023}, author = {Kim, C and Kim, JG and Kim, KY}, title = {Anti-Candida Potential of Sclareol in Inhibiting Growth, Biofilm Formation, and Yeast-Hyphal Transition.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {36675919}, issn = {2309-608X}, support = {GRRC-KyungHee2020(B04)//GRRC Program of Gyeonggi province/ ; }, abstract = {Even though Candida albicans commonly colonizes on most mucosal surfaces including the vaginal and gastrointestinal tract, it can cause candidiasis as an opportunistic infectious fungus. The emergence of resistant Candida strains and the toxicity of anti-fungal agents have encouraged the development of new classes of potential anti-fungal agents. Sclareol, a labdane-type diterpene, showed anti-Candida activity with a minimum inhibitory concentration of 50 μg/mL in 24 h based on a microdilution anti-fungal susceptibility test. Cell membrane permeability with propidium iodide staining and mitochondrial membrane potential with JC-1 staining were increased in C. albicans by treatment of sclareol. Sclareol also suppressed the hyphal formation of C. albicans in both liquid and solid media, and reduced biofilm formation. Taken together, sclareol induces an apoptosis-like cell death against Candida spp. and suppressed biofilm and hyphal formation in C. albicans. Sclareol is of high interest as a novel anti-fungal agent and anti-virulence factor.}, } @article {pmid36675292, year = {2023}, author = {Wiessner, A and Wassmann, T and Wiessner, JM and Schubert, A and Wiechens, B and Hampe, T and Bürgers, R}, title = {In Vivo Biofilm Formation on Novel PEEK, Titanium, and Zirconia Implant Abutment Materials.}, journal = {International journal of molecular sciences}, volume = {24}, number = {2}, pages = {}, pmid = {36675292}, issn = {1422-0067}, mesh = {Humans ; Titanium ; *Peri-Implantitis ; Polyethylene Glycols ; Ketones ; Biofilms ; Zirconium ; Dental Materials ; *Dental Implants ; Materials Testing ; }, abstract = {The formation of biofilms on the surface of dental implants and abutment materials may lead to peri-implantitis and subsequent implant failure. Recently, innovative materials such as polyether-ether-ketone (PEEK) and its modifications have been used as abutment materials. However, there is limited knowledge on microbial adhesion to PEEK materials. The aim of this in vivo study was to investigate biofilm formation on the surface of conventional (titanium and zirconia) and PEEK implant abutment materials. Split specimens of titanium, zirconia, PEEK, and modified PEEK (PEEK-BioHPP) were manufactured, mounted in individual removable acrylic upper jaw splints, and worn by 20 healthy volunteers for 24 h. The surface roughness was determined using widefield confocal microscopy. Biofilm accumulation was investigated by fluorescence microscopy and quantified by imaging software. The surface roughness of the investigated materials was <0.2 µm and showed no significant differences between the materials. Zirconia showed the lowest biofilm formation, followed by titanium, PEEK, and PEEK-BioHPP. Differences were significant (p < 0.001) between the investigated materials, except for the polyether-ether-ketones. Generally, biofilm formation was significantly higher (p < 0.05) in the posterior region of the oral cavity than in the anterior region. The results of the present study show a material-dependent susceptibility to biofilm formation. The risk of developing peri-implantitis may be reduced by a specific choice of abutment material.}, } @article {pmid36675120, year = {2023}, author = {Matthes, R and Jablonowski, L and Miebach, L and Pitchika, V and Holtfreter, B and Eberhard, C and Seifert, L and Gerling, T and Schlüter, R and Kocher, T and Bekeschus, S}, title = {In-Vitro Biofilm Removal Efficacy Using Water Jet in Combination with Cold Plasma Technology on Dental Titanium Implants.}, journal = {International journal of molecular sciences}, volume = {24}, number = {2}, pages = {}, pmid = {36675120}, issn = {1422-0067}, support = {13N14478//Federal Ministry of Education and Research/ ; 13N14479//Federal Ministry of Education and Research/ ; 13N14480//Federal Ministry of Education and Research/ ; 03Z22Di1//Federal Ministry of Education and Research/ ; }, mesh = {Humans ; Titanium/chemistry ; *Plasma Gases/pharmacology/chemistry ; Leukocytes, Mononuclear ; Surface Properties ; Biofilms ; *Anti-Infective Agents/pharmacology ; Inflammation ; *Dental Implants ; }, abstract = {Peri-implantitis-associated inflammation can lead to bone loss and implant failure. Current decontamination measures are ineffective due to the implants' complex geometry and rough surfaces providing niches for microbial biofilms. A modified water jet system (WaterJet) was combined with cold plasma technology (CAP) to achieve superior antimicrobial efficacy compared to cotton gauze treatment. Seven-day-old multi-species-contaminated titanium discs and implants were investigated as model systems. The efficacy of decontamination on implants was determined by rolling the implants over agar and determining colony-forming units supported by scanning electron microscopy image quantification of implant surface features. The inflammatory consequences of mono and combination treatments were investigated with peripheral blood mononuclear cell surface marker expression and chemokine and cytokine release profiles on titanium discs. In addition, titanium discs were assayed using fluorescence microscopy. Cotton gauze was inferior to WaterJet treatment according to all types of analysis. In combination with the antimicrobial effect of CAP, decontamination was improved accordingly. Mono and CAP-combined treatment on titanium surfaces alone did not unleash inflammation. Simultaneously, chemokine and cytokine release was dramatically reduced in samples that had benefited from additional antimicrobial effects through CAP. The combined treatment with WaterJet and CAP potently removed biofilm and disinfected rough titanium implant surfaces. At the same time, non-favorable rendering of the surface structure or its pro-inflammatory potential through CAP was not observed.}, } @article {pmid36674518, year = {2023}, author = {Diban, F and Di Lodovico, S and Di Fermo, P and D'Ercole, S and D'Arcangelo, S and Di Giulio, M and Cellini, L}, title = {Biofilms in Chronic Wound Infections: Innovative Antimicrobial Approaches Using the In Vitro Lubbock Chronic Wound Biofilm Model.}, journal = {International journal of molecular sciences}, volume = {24}, number = {2}, pages = {}, pmid = {36674518}, issn = {1422-0067}, mesh = {Humans ; *Anti-Infective Agents/pharmacology/therapeutic use ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Persistent Infection ; *Wound Infection/drug therapy/microbiology ; Biofilms ; Pseudomonas aeruginosa ; }, abstract = {Chronic wounds have harmful effects on both patients and healthcare systems. Wound chronicity is attributed to an impaired healing process due to several host and local factors that affect healing pathways. The resulting ulcers contain a wide variety of microorganisms that are mostly resistant to antimicrobials and possess the ability to form mono/poly-microbial biofilms. The search for new, effective and safe compounds to handle chronic wounds has come a long way throughout the history of medicine, which has included several studies and trials of conventional treatments. Treatments focus on fighting the microbial colonization that develops in the wound by multidrug resistant pathogens. The development of molecular medicine, especially in antibacterial agents, needs an in vitro model similar to the in vivo chronic wound environment to evaluate the efficacy of antimicrobial agents. The Lubbock chronic wound biofilm (LCWB) model is an in vitro model developed to mimic the pathogen colonization and the biofilm formation of a real chronic wound, and it is suitable to screen the antibacterial activity of innovative compounds. In this review, we focused on the characteristics of chronic wound biofilms and the contribution of the LCWB model both to the study of wound poly-microbial biofilms and as a model for novel treatment strategies.}, } @article {pmid36674132, year = {2023}, author = {Chajęcka-Wierzchowska, W and Gajewska, J and Zakrzewski, AJ and Caggia, C and Zadernowska, A}, title = {Molecular Analysis of Pathogenicity, Adhesive Matrix Molecules (MSCRAMMs) and Biofilm Genes of Coagulase-Negative Staphylococci Isolated from Ready-to-Eat Food.}, journal = {International journal of environmental research and public health}, volume = {20}, number = {2}, pages = {}, pmid = {36674132}, issn = {1660-4601}, support = {DEC-2016/23/D/NZ9/01404//National Science Center/ ; 17.610.015.110//University of Warmia and Mazury in Olsztyn/ ; }, mesh = {Humans ; *Coagulase/genetics ; Staphylococcus aureus/genetics ; Virulence ; *Staphylococcal Infections/microbiology ; Polymerase Chain Reaction ; Staphylococcus/genetics ; Biofilms ; DNA Transposable Elements ; }, abstract = {This paper provides a snapshot on the pathogenic traits within CoNS isolated from ready-to-eat (RTE) food. Eighty-five strains were subjected to biofilm and slime production, as well as biofilm-associated genes (icaA, icaD, icaB, icaC, eno, bap, bhp, aap, fbe, embP and atlE), the insertion sequence elements IS256 and IS257 and hemolytic genes. The results showed that the most prevalent determinants responsible for the primary adherence were eno (57.6%) and aap (56.5%) genes. The icaADBC operon was detected in 45.9% of the tested strains and was correlated to slime production. Moreover, most strains carrying the icaADBC operon simultaneously carried the IS257 insertion sequence element. Among the genes encoding for surface proteins involved in the adhesion to abiotic surfaces process, atlE was the most commonly (31.8%) followed by bap (4.7%) and bhp (1.2%). The MSCRAMMs, including fbe and embp were detected in the 11.8% and 28.2% of strains, respectively. A high occurrence of genes involved in the hemolytic toxin production were detected, such as hla_yiD (50.6%), hlb (48.2%), hld (41.2%) and hla_haem (34.1%). The results of the present study revealed an unexpected occurrence of the genes involved in biofilm production and the high hemolytic activity among the CoNS strains, isolated from RTE food, highlighting that this group seems to be acquiring pathogenic traits similar to those of S. aureus, suggesting the need to be included in the routine microbiological analyses of food.}, } @article {pmid36672846, year = {2022}, author = {Asante, J and Abia, ALK and Anokwah, D and Hetsa, BA and Fatoba, DO and Bester, LA and Amoako, DG}, title = {Phenotypic and Genomic Insights into Biofilm Formation in Antibiotic-Resistant Clinical Coagulase-Negative Staphylococcus Species from South Africa.}, journal = {Genes}, volume = {14}, number = {1}, pages = {}, pmid = {36672846}, issn = {2073-4425}, support = {Not Applicable//University of KwaZulu-Natal/ ; }, mesh = {Humans ; *Anti-Bacterial Agents/pharmacology ; Coagulase/genetics/metabolism ; *Staphylococcal Infections/drug therapy/genetics ; South Africa ; Staphylococcus/genetics ; Phenotype ; Genomics ; Biofilms ; }, abstract = {The work aims to investigate biofilm formation and biofilm/adhesion-encoding genes in coagulase-negative staphylococci (CoNS) species recovered from blood culture isolates. Eighty-nine clinical CoNS were confirmed using the VITEK 2 system, and antibiotic susceptibility testing of isolates was conducted using the Kirby-Bauer disk diffusion method against a panel of 20 antibiotics. Isolates were qualitatively screened using the Congo red agar medium. Quantitative assays were performed on microtiter plates, where the absorbances of the solubilised biofilms were recorded as optical densities and quantified. In all, 12.4% of the isolates were strong biofilm formers, 68.5% had moderate biofilm capacity, and 17.9% showed weak capacity. A subset of 18 isolates, mainly methicillin-resistant S. epidermidis, were investigated for adherence-related genes using whole-genome sequencing and bioinformatics analysis. The highest antibiotic resistance rates for strongly adherent isolates were observed against penicillin (100%) and cefoxitin (81.8%), but the isolates showed no resistance to linezolid (0.0%) and tigecycline (0.0%). The icaABC genes involved in biofilm formation were detected in 50% of the screened isolates. Other adherence-related genes, including autolysin gene atl (88.8%), elastin binding protein gene ebp (94.4%), cell wall-associated fibronectin-binding protein gene ebh (66.7%), clumping factor A gene clfA (5.5%), and pili gene ebpC (22.2%) were also found. The insertion sequence IS256, involved in biofilm formation, was found in 10/18 (55.5%) screened isolates. We demonstrate a high prevalence of biofilm-forming coagulase-negative staphylococci associated with various resistance phenotypes and a substantial agreement between the possession of biofilm-associated genes and the biofilm phenotype.}, } @article {pmid36671356, year = {2023}, author = {Laconi, A and Tolosi, R and Apostolakos, I and Piccirillo, A}, title = {Biofilm Formation Ability of ESBL/pAmpC-Producing Escherichia coli Isolated from the Broiler Production Pyramid.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671356}, issn = {2079-6382}, abstract = {Escherichia coli able to produce extended spectrum β-lactamases (ESBLs) and plasmid-mediated AmpC β-lactamases (pAmpCs) represents a serious threat to public health, since these genes confer resistance to critically important antimicrobials (i.e., third generation cephalosporins) and can be transferred to non-resistant bacteria via plasmids. E. coli are known to be able to form a biofilm, which represents a favorable environment for the exchange of resistance determinants. Here, we assessed the ability of 102 ESBL/pAmpC-producing E. coli isolated from the broiler production pyramid to form a biofilm and to identify genetic factors involved in biofilm formation. All but one of the ESBL/pAmpC-producing E. coli were able to form a biofilm, and this represents a great concern to public health. E. coli belonging to phylogroups D, E, and F, as well as strains harboring the blaCTX-M-type gene, seem to be associated with an increased biofilm capability (p < 0.05). Furthermore, virulence genes involved in adherence and invasion (i.e., csgBAC, csgDEFG, matABCDEF, and sfaX) seem to enhance biofilm formation in E. coli. Efforts should be made to reduce the presence of ESBL/pAmpC- and biofilm-producing E. coli in the broiler production pyramid and, therefore, the risk of dissemination of resistant bacteria and genes.}, } @article {pmid36671344, year = {2023}, author = {Puvača, N and Ljubojević Pelić, D and Pelić, M and Bursić, V and Tufarelli, V and Piemontese, L and Vuković, G}, title = {Microbial Resistance to Antibiotics and Biofilm Formation of Bacterial Isolates from Different Carp Species and Risk Assessment for Public Health.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671344}, issn = {2079-6382}, abstract = {The aim of this research was to investigate the effects of biofilm on antibiotic resistance of the bacterial isolates present in fish meat and to assess the risk of antibiotic residues for public health. Common carp, silver carp and grass carp fishes were purchased from retail stores for an in vitro biofilm investigation and a drug-resistant pattern determination. In all samples, up to 10[4] CFU/g of bacteria, such as Escherichia coli, Aeromonas hydrophila, Shewanella putrefaciens, Vibrio spp. and Staphylococcus spp., were observed. Isolates from the samples and their biofilms were subjected to an antibiogram assay using antibiotics such as amoxicillin, ampicillin, cefotaxime, ciprofloxacin, chloramphenicol, gentamicin, streptomycin, tetracycline and trimethoprim. Obtained results showed that some of the isolates were sensitive to antibiotics and some were resistant. Results of LC-MS/MS analysis showed that antibiotics residues were present in fish samples in the range between 4.9 and 199.4 µg/kg, with a total sum of 417.1 µg/kg. Estimated daily intake (EDI) was established to be 0.274 μg/kg of body weight/day for men and 0.332 μg/kg of body weight/day for women, with an acceptable daily intake (ADI) of 8.5 and 7.0 µg/kg of body weight/day for men and women, respectively. The results of the present study, therefore, highlight the safe consumption of fresh fish.}, } @article {pmid36671333, year = {2023}, author = {Dong, CL and Che, RX and Wu, T and Qu, QW and Chen, M and Zheng, SD and Cai, XH and Wang, G and Li, YH}, title = {New Characterization of Multi-Drug Resistance of Streptococcus suis and Biofilm Formation from Swine in Heilongjiang Province of China.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671333}, issn = {2079-6382}, support = {LH2020C024//Heilongjiang Provincial Natural Science Foundation of China/ ; 32102726//National Natural Science Foundation of China/ ; 32072908//National Natural Science Foundation of China/ ; CARS-35//China Agriculture Research System of MOF and MARA/ ; }, abstract = {The aim of this study was to investigate the antimicrobial resistance profiles and genotypes of Streptococcus suis in Heilongjiang Province, China. A total of 29 S. suis were isolated from 332 samples collected from 6 pig farms. The results showed that serotypes 2, 4 and 9 were prevalent, and all the clinical isolates were resistant to at least two antibacterial drugs. The most resisted drugs were macrolides, and the least resisted drugs were fluoroquinolones. Resistant genes ermB and aph (3')-IIIa were highly distributed among the isolates, with the detection rates of 79.31% and 75.86%. The formation of biofilm could be observed in all the isolated S. suis, among which D-1, LL-1 and LL-3 strains formed stronger biofilm structure than other strains. The results indicate that S. suis in Heilongjiang Province presents a multi-drug resistance to commonly used antimicrobial drugs, which was caused by the same target gene, the dissemination of drug resistance genes, and bacterial biofilm.}, } @article {pmid36671319, year = {2023}, author = {Prinz, J and Wink, M and Neuhaus, S and Grob, MC and Walt, H and Bosshard, PP and Achermann, Y}, title = {Effective Biofilm Eradication on Orthopedic Implants with Methylene Blue Based Antimicrobial Photodynamic Therapy In Vitro.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671319}, issn = {2079-6382}, support = {na//Monique Dornonville de la Cour Foundation/ ; na//Wolfermann-Naegeli Foundation/ ; }, abstract = {Periprosthetic joint infections (PJI) are difficult to treat due to biofilm formation on implant surfaces, often requiring removal or exchange of prostheses along with long-lasting antibiotic treatment. This in vitro study investigated the effect of methylene blue photodynamic therapy (MB-PDT) on PJI-causing biofilms on different implant materials. MB-PDT (664 nm LED, 15 J/cm[2]) was tested on different Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Cutibacterium acnes strains in both planktonic form and grown in early and mature biofilms on prosthetic materials (polyethylene, titanium alloys, cobalt-chrome-based alloys, and bone cement). The minimum bactericidal concentration with 100% killing (MBC100%) was determined. Chemical and topographical alterations were investigated on the prosthesis surfaces after MB-PDT. Results showed a MBC100% of 0.5-5 μg/mL for planktonic bacteria and 50-100 μg/mL for bacteria in biofilms-independent of the tested strain, the orthopedic material, or the maturity of the biofilm. Material testing showed no relevant surface modification. MB-PDT effectively eradicated common PJI pathogens on arthroplasty materials without damage to the materials, suggesting that MB-PDT could be used as a novel treatment method, replacing current, more invasive approaches and potentially shortening the antibiotic treatment in PJI. This would improve quality of life and reduce morbidity, mortality, and high health-care costs.}, } @article {pmid36671311, year = {2023}, author = {Kaur, H and Chaudhary, N and Modgil, V and Kalia, M and Kant, V and Mohan, B and Bhatia, A and Taneja, N}, title = {In Vitro and In Vivo Studies of Heraclenol as a Novel Bacterial Histidine Biosynthesis Inhibitor against Invasive and Biofilm-Forming Uropathogenic Escherichia coli.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671311}, issn = {2079-6382}, abstract = {Globally, urinary tract infections (UTIs) are one of the most frequent bacterial infections. Uropathogenic Escherichia coli (UPEC) are the predominant etiological agents causing community and healthcare-associated UTIs. Biofilm formation is an important pathogenetic mechanism of UPEC responsible for chronic and recurrent infections. The development of high levels of antimicrobial resistance (AMR) among UPEC has complicated therapeutic management. Newer antimicrobial agents are needed to tackle the increasing trend of AMR and inhibit biofilms. Heraclenol is a natural furocoumarin compound that inhibits histidine biosynthesis selectively. In this study, for the first time, we have demonstrated the antimicrobial and antibiofilm activity of heraclenol against UPEC. The drug reduced the bacterial load in the murine catheter UTI model by ≥4 logs. The drug effectively reduced bacterial loads in kidney, bladder, and urine samples. On histopathological examination, heraclenol treatment showed a reversal of inflammatory changes in the bladder and kidney tissues. It reduced the biofilm formation by 70%. The MIC value of heraclenol was observed to be high (1024 µg/mL), though the drug at MIC concentration did not have significant cytotoxicity on the Vero cell line. Further molecular docking revealed that heraclenol binds to the active site of the HisC, thereby preventing its activation by native substrate, which might be responsible for its antibacterial and antibiofilm activity. Since the high MIC of heraclenol is not achievable clinically in human tissues, further chemical modifications will be required to lower the drug's MIC value and increase its potency. Alternatively, its synergistic action with other antimicrobials may also be studied.}, } @article {pmid36671272, year = {2022}, author = {Barros, ILE and Veiga, FF and de Castro-Hoshino, LV and Souza, M and Malacrida, AM and Diniz, BV and Dos Santos, RS and Bruschi, ML and Baesso, ML and Negri, M and Svidzinski, TIE}, title = {Performance of Two Extracts Derived from Propolis on Mature Biofilm Produced by Candida albicans.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671272}, issn = {2079-6382}, abstract = {Species of the Candida genus represent the third most common cause of onychomycosis, the most frequent and difficult to treat nail infection. Onychomycosis has been attributed to fungi organized in biofilm and some natural products have proved promising for its treatment. This study aimed to evaluate the antibiofilm activity of propolis extract (PE) and its by-product (WPE) on 7-day preformed biofilms produced by Candida albicans in polystyrene microplates, as well as in an ex vivo model on human nail fragments. The cytotoxicity and permeation capacity were also assessed. Firstly, multiple parameters were evaluated over 7 days to elucidate the dynamics of biofilm formation by C. albicans. The cell viability and total biomass did not vary much from the beginning; however, days 3 and 4 were crucial in terms of metabolic activity, which was significantly increased, and the levels of extracellular matrix components, wherein proteins and nucleic acids experienced an increase, but polysaccharide levels dropped. Architecturally, one-day biofilm showed a monolayer of organized cells (blastoconidia, hyphae, and pseudohyphae), while in the seven-day biofilm there was a three-dimensional well-structured and complex biofilm. This yeast was also able to form a biofilm on both surfaces of the nail, without an additional nutritional source. Both extracts showed excellent antibiofilm activity against the 7-day preformed biofilm and were not toxic to Vero cells at concentrations compatible with the antifungal and antibiofilm activities. Both extracts permeated the experimentally infected nail, with WPE being more efficient. The results of this study, taken together, reinforce the potential of these natural products, containing propolis, as a safe option for the topical treatment of onychomycosis.}, } @article {pmid36671269, year = {2022}, author = {Sparbrod, M and Gager, Y and Koehler, AK and Jentsch, H and Stingu, CS}, title = {Relationship between Phenotypic and Genotypic Resistance of Subgingival Biofilm Samples in Patients with Periodontitis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671269}, issn = {2079-6382}, abstract = {The phenotypic expression of antibiotic resistance genes (ARGs) can hamper the use of antibiotics as adjuncts to subgingival instrumentation in the treatment of periodontitis patients. The aim of the study was to analyze the relationship between the phenotypic and genotypic resistance against ampicillin-sulbactam, clindamycin, doxycycline and metronidazole of subgingival biofilm samples from 19 periodontitis patients. Samples were analyzed with shotgun sequencing and cultivated anaerobically for 7 days on microbiological culture media incorporating antibiotics. All growing isolates were identified to the species level using MALDI-TOF-MS and sequence analysis of the 16S ribosomal RNA (rRNA) gene. Phenotypic resistance was determined using EUCAST-breakpoints. The genetic profile of eight patients matched completely with phenotypical resistance to the tested antibiotics. The positive predictive values varied from 1.00 for clindamycin to 0.57 for doxycycline and 0.25 for ampicillin-sulbactam. No sample contained the nimI gene. It can be concluded that antibiotic resistance may be polygenetic and genes may be silent. Every biofilm sample harboring erm genes was phenotypic resistant. The absence of cfx and tet genes correlated to 100%, respectively, to 75%, with the absence of phenotypic resistance. The absence of nimI genes leads to the assumption that constitutive resistance among several species could explain the resistance to metronidazole.}, } @article {pmid36671255, year = {2022}, author = {Ciarolla, AA and Lapin, N and Williams, D and Chopra, R and Greenberg, DE}, title = {Physical Approaches to Prevent and Treat Bacterial Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671255}, issn = {2079-6382}, abstract = {Prosthetic joint infection (PJI) presents several clinical challenges. This is in large part due to the formation of biofilm which can make infection eradication exceedingly difficult. Following an extensive literature search, this review surveys a variety of non-pharmacological methods of preventing and/or treating biofilm within the body and how they could be utilized in the treatment of PJI. Special attention has been paid to physical strategies such as heat, light, sound, and electromagnetic energy, and their uses in biofilm treatment. Though these methods are still under study, they offer a potential means to reduce the morbidity and financial burden related to multiple stage revisions and prolonged systemic antibiotic courses that make up the current gold standard in PJI treatment. Given that these options are still in the early stages of development and offer their own strengths and weaknesses, this review offers an assessment of each method, the progress made on each, and allows for comparison of methods with discussion of future challenges to their implementation in a clinical setting.}, } @article {pmid36671212, year = {2022}, author = {Peng, Q and Tang, X and Dong, W and Sun, N and Yuan, W}, title = {A Review of Biofilm Formation of Staphylococcus aureus and Its Regulation Mechanism.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36671212}, issn = {2079-6382}, support = {No. 2020A1515011326 and 2021A1515011360//Natural Science Foundation of Guangdong Province/ ; No.81703333//National Natural Science Foundation of China/ ; No.202102080469//Guangzhou Science and Technology Project/ ; No.2020A010015//Guangzhou Health Science and Technology Project/ ; No.C2021077//Medical Scientific Research Foundation of Guangdong Province/ ; }, abstract = {Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation.}, } @article {pmid36670360, year = {2023}, author = {Zang, YM and Liu, JF and Li, G and Zhao, M and Yin, GM and Zhang, ZP and Jia, W}, title = {The first case of Escherichia fergusonii with biofilm in China and literature review.}, journal = {BMC infectious diseases}, volume = {23}, number = {1}, pages = {35}, pmid = {36670360}, issn = {1471-2334}, support = {2019FY101200//Special Foundation for National Science and Technology Basic Research Program of China/ ; 2021BEG03090//Key Research and Development Project of Ningxia Hui Autonomous Region/ ; }, mesh = {Animals ; Humans ; *Anti-Bacterial Agents/pharmacology/therapeutic use ; Escherichia ; *Anti-Infective Agents ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Escherichia fergusonii is a rare opportunistic pathogen in humans and animals, especially with biofilm.

METHODS: In one case, E. fergusonii with biofilm was detected in the bile, and silver staining was used to prove it had biofilm. The clinical characteristics and drug susceptibility of eight cases of E. fergusonii retrieved from the literature were also summarized.

RESULTS: This is a case of E. fergusonii with biofilm, which has not been reported in China. The 8 cases retrieved from the literature did not specify whether they had biofilm, but we analyzed their clinical characteristics and drug susceptibility. All patients were treated with antimicrobial drugs. 8 cases showed sensitivity to piperacillin/tazobactam and imipenem in 6 cases (75%), but poor sensitivity to levofloxacin and ciprofloxacin.

CONCLUSION: The silver staining method proved biofilm in this case, which is the first case of E. fergusonii with biofilm in China.}, } @article {pmid36670157, year = {2023}, author = {da Silva Barreira, D and Laurent, J and Lourenço, J and Novion Ducassou, J and Couté, Y and Guzzo, J and Rieu, A}, title = {Membrane vesicles released by Lacticaseibacillus casei BL23 inhibit the biofilm formation of Salmonella Enteritidis.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {1163}, pmid = {36670157}, issn = {2045-2322}, mesh = {*Salmonella enteritidis ; *Lacticaseibacillus casei ; Lacticaseibacillus ; Biofilms ; }, abstract = {Biofilms represent a major concern in the food industry and healthcare. The use of probiotic bacteria and their derivatives as an alternative to conventional treatments to fight biofilm development is a promising option that has provided convincing results in the last decades. Recently, membrane vesicles (MVs) produced by probiotics have generated considerable interest due to the diversity of roles they have been associated with. However, the antimicrobial activity of probiotic MVs remains to be studied. In this work, we showed that membrane vesicles produced by Lacticaseibacillus casei BL23 (LC-MVs) exhibited strong antibiofilm activity against Salmonella enterica serovar Enteritidis (S. Enteritidis) without affecting bacterial growth. Furthermore, we found that LC-MVs affected the early stages of S. Enteritidis biofilm development and prevented attachment of bacteria to polystyrene surfaces. Importantly, LC-MVs did not impact the biomass of already established biofilms. We also demonstrated that the antibiofilm activity depended on the proteins associated with the LC-MV fraction. Finally, two peptidoglycan hydrolases (PGHs) were found to be associated with the antibiofilm activity of LC-MVs. Overall, this work allowed to identify the antibiofilm properties of LC-MVs and paved the way for the use of probiotic MVs against the development of negative biofilms.}, } @article {pmid36669724, year = {2023}, author = {Gonçalves, B and Barbosa, A and Soares, AR and Henriques, M and Silva, S}, title = {Sfl1 is required for Candida albicans biofilm formation under acidic conditions.}, journal = {Biochimie}, volume = {209}, number = {}, pages = {37-43}, doi = {10.1016/j.biochi.2023.01.011}, pmid = {36669724}, issn = {1638-6183}, mesh = {*Candida albicans/genetics ; *Fungal Proteins/genetics/metabolism ; Candida ; Gene Expression Profiling ; Biofilms ; }, abstract = {Candida albicans is a common Candida species, responsible for infections in various anatomical sites under different environmental conditions, aggravated in the presence of its biofilms. As such, this study aimed to reveal the regulation of C. albicans biofilms under acidic conditions by the transcription factor Sfl1, whose role on biofilm formation is unclear. For that, microbiologic and transcriptomic analyses were performed with the knock-out mutant C. albicans sfl1Δ/sfl1Δ and its parental strain SN76, grown in planktonic and biofilm lifestyles at pH 4 (vaginal pH). The results revealed that despite being a filamentation repressor Sf1 is required for maximal biofilm formation under acidic conditions. Additionally, Sfl1 was found to induce 275 and 126 genes in biofilm and planktonic cells, respectively, with an overlap of 19 genes. The functional distribution of Sfl1 targets was similar in planktonic and biofilm modes but an enrichment of carbohydrate metabolism function was found in biofilm cells, including some genes encoding proteins involved in the biofilm matrix production. Furthermore, this study shows that the regulatory network of Sfl1 in acidic biofilms is complex and includes positive and negative regulation of transcription factors involved in adhesion and biofilm formation, such as Ahr1, Brg1, Tye7, Tec1, Wor1, and some of their targets. Overall, this study shows that Sfl1 is a relevant regulator of C. albicans biofilm formation in acidic environments and contributes to a better understanding of C. albicans virulence under acidic conditions.}, } @article {pmid36669662, year = {2023}, author = {Villa, F and Ludwig, N and Mazzini, S and Scaglioni, L and Fuchs, AL and Tripet, B and Copié, V and Stewart, PS and Cappitelli, F}, title = {A desiccated dual-species subaerial biofilm reprograms its metabolism and affects water dynamics in limestone.}, journal = {The Science of the total environment}, volume = {868}, number = {}, pages = {161666}, doi = {10.1016/j.scitotenv.2023.161666}, pmid = {36669662}, issn = {1879-1026}, mesh = {*Calcium Carbonate ; *Biofilms ; Desiccation ; }, abstract = {Understanding the impact of sessile communities on underlying materials is of paramount importance in stone conservation. Up until now, the critical role of subaerial biofilms (SABs) whether they are protective or deteriorative remains unclear, especially under desiccation. The interest in desiccated SABs is raised by the prediction of an increase in drought events in the next decades that will affect the Mediterranean regions' rich stone heritage as never before. Thus, the main goal of this research is to study the effects of desiccation on both the biofilms' eco-physiology and its impacts on the lithic substrate. To this end, we used a dual-species model system composed of a phototroph and a chemotroph to simulate biofilm behavior on stone heritage. We found that drought altered the phototroph-chemotroph balance and enriched the biofilm matrix with proteins and DNA. Desiccated SABs underwent a shift in metabolism to fermentation and a decrease in oxidative stress. Additionally, desiccated SABs changed the water-related dynamics (adsorption, evaporation, and wetting properties) in limestone. Water absorption experiments showed that desiccated SABs protected the stone from rapid water uptake, while a thermographic survey indicated a delay in water evaporation. Spilling-drop tests revealed a change in the wettability of the stone-SAB interface, which affected the water transport properties of the stone. Finally, desiccated SABs reduced stone swelling in the presence of water vapor. The biodeteriorative and bioprotective implications of desiccated SABs on the stone were ultimately assessed.}, } @article {pmid36669302, year = {2023}, author = {Si, Z and Li, J and Ruan, L and Reghu, S and Ooi, YJ and Li, P and Zhu, Y and Hammond, PT and Verma, CS and Bazan, GC and Pethe, K and Chan-Park, MB}, title = {Designer co-beta-peptide copolymer selectively targets resistant and biofilm Gram-negative bacteria.}, journal = {Biomaterials}, volume = {294}, number = {}, pages = {122004}, doi = {10.1016/j.biomaterials.2023.122004}, pmid = {36669302}, issn = {1878-5905}, mesh = {Animals ; Mice ; *Peptides ; *Anti-Infective Agents ; Gram-Negative Bacteria/metabolism ; Lipopolysaccharides ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Microbial Sensitivity Tests ; Mammals/metabolism ; }, abstract = {New antimicrobials are urgently needed to combat Gram-negative bacteria, particularly multi-drug resistant (MDR) and phenotypically resistant biofilm species. At present, only sequence-defined alpha-peptides (e.g. polymyxin B) can selectively target Gram-negative bacterial lipopolysaccharides. We show that a copolymer, without a defined sequence, shows good potency against MDR Gram-negative bacteria including its biofilm form. The tapered blocky co-beta-peptide with controlled N-terminal hydrophobicity (#4) has strong interaction with the Gram-negative bacterial lipopolysaccharides via its backbone through electrostatic and hydrogen bonding interactions but not the Gram-positive bacterial and mammalian cell membranes so that this copolymer is non-toxic to these two latter cell types. The new #4 co-beta-peptide selectively kills Gram-negative bacteria with low cytotoxicity both in vitro and in a mouse biofilm wound infection model. This strategy provides a new concept for the design of Gram-negative selective antimicrobial peptidomimetics against MDR and biofilm species.}, } @article {pmid36669095, year = {2023}, author = {Lorenz, K and Preem, L and Sagor, K and Putrinš, M and Tenson, T and Kogermann, K}, title = {Development of In Vitro and Ex Vivo Biofilm Models for the Assessment of Antibacterial Fibrous Electrospun Wound Dressings.}, journal = {Molecular pharmaceutics}, volume = {20}, number = {2}, pages = {1230-1246}, pmid = {36669095}, issn = {1543-8392}, mesh = {Swine ; Animals ; *Anti-Bacterial Agents/pharmacology/therapeutic use ; Chloramphenicol/pharmacology ; *Wound Infection/microbiology ; Biofilms ; Bandages ; }, abstract = {Increasing evidence suggests that the chronicity of wounds is associated with the presence of bacterial biofilms. Therefore, novel wound care products are being developed, which can inhibit biofilm formation and/or treat already formed biofilms. A lack of standardized assays for the analysis of such novel antibacterial drug delivery systems enhances the need for appropriate tools and models for their characterization. Herein, we demonstrate that optimized and biorelevant in vitro and ex vivo wound infection and biofilm models offer a convenient approach for the testing of novel antibacterial wound dressings for their antibacterial and antibiofilm properties, allowing one to obtain qualitative and quantitative results. The in vitro model was developed using an electrospun (ES) thermally crosslinked gelatin-glucose (GEL-Glu) matrix and an ex vivo wound infection model using pig ear skin. Wound pathogens were used for colonization and biofilm development on the GEL-Glu matrix or pig skin with superficial burn wounds. The in vitro model allowed us to obtain more reproducible results compared with the ex vivo model, whereas the ex vivo model had the advantage that several pathogens preferred to form a biofilm on pig skin compared with the GEL-Glu matrix. The in vitro model functioned poorly for Staphylococcus epidermidis biofilm formation, but it worked well for Escherichia coli and Staphylococcus aureus, which were able to use the GEL-Glu matrix as a nutrient source and not only as a surface for biofilm growth. On the other hand, all tested pathogens were equally able to produce a biofilm on the surface of pig skin. The developed biofilm models enabled us to compare different ES dressings [pristine and chloramphenicol-loaded polycaprolactone (PCL) and PCL-poly(ethylene oxide) (PEO) (PCL/PEO) dressings] and understand their biofilm inhibition and treatment properties on various pathogens. Furthermore, we show that biofilms were formed on the wound surface as well as on a wound dressing, indicating that the demonstrated methods mimic well the in vivo situation. Colony forming unit (CFU) counting and live biofilm matrix as well as bacterial DNA staining together with microscopic imaging were performed for biofilm quantification and visualization, respectively. The results showed that both wound biofilm models (in vitro and ex vivo) enabled the evaluation of the desired antibiofilm properties, thus facilitating the design and development of more effective wound care products and screening of various formulations and active substances.}, } @article {pmid36661559, year = {2023}, author = {Cobb, CM and Harrel, SK and Zhao, D and Spencer, P}, title = {Effect of EDTA Gel on Residual Subgingival Calculus and Biofilm: An In Vitro Pilot Study.}, journal = {Dentistry journal}, volume = {11}, number = {1}, pages = {}, pmid = {36661559}, issn = {2304-6767}, abstract = {BACKGROUND: Residual calculus, following scaling and root planing (SRP), is associated with persistent inflammation and the progression of periodontitis. This study examined the effects of a 24% neutral ethylenediaminetetraacetic acid (EDTA) gel on subgingival calculus and biofilms.

METHODS: Eleven single-rooted teeth extracted because of severe periodontal disease were randomly assigned to the following treatment groups: (1) three teeth served as untreated controls; (2) three teeth were treated by scaling and root planing (SRP) only; and (3) three teeth were treated by SRP + EDTA. The remaining two teeth, one SRP only and the other SRP + EDTA were designated for energy-dispersive X-ray spectroscopy (EDS) analysis. EDTA gel was placed on the SRP surface for 2 min and then burnished with a sterile cotton pellet.

RESULTS: SRP + EDTA treated specimens exhibited severely damaged biofilm and the disruption of the extracellular polymeric matrix. EDS scans of the smear layer and calculus featured reductions in the Weight % and Atomic % for N, F, Na, and S and increases in Mg, P, and Ca.

CONCLUSIONS: A 25% neutral EDTA gel was applied after SRP severely disrupted the residual biofilm and altered the character of dental calculus and the smear layer as shown by reductions in the Weight % and Atomic % for N, F, Na, and S and increases in Mg, P, and Ca.}, } @article {pmid36661550, year = {2023}, author = {Baybekov, O and Stanishevskiy, Y and Sachivkina, N and Bobunova, A and Zhabo, N and Avdonina, M}, title = {Isolation of Clinical Microbial Isolates during Orthodontic Aligner Therapy and Their Ability to Form Biofilm.}, journal = {Dentistry journal}, volume = {11}, number = {1}, pages = {}, pmid = {36661550}, issn = {2304-6767}, abstract = {The purpose of this study is to calculate microbiological composition of aligners after a day of wearing them. To date, the dental market for orthodontists offers many ways to correct bites. Aligners are transparent and almost invisible from the teeth. They are used for everyday wear to correct the incorrect position of the teeth, which was once considered the prerogative of braces. Scientists worldwide have repeatedly considered questions regarding the interaction between aligners and the oral cavity's microflora; however, the emphasis has mainly shifted toward species composition and antibiotic resistance. The various properties of these microorganisms, including biofilm formation, adhesion to various cells, and the ability to phagocytize, have not been studied so widely. In addition, these characteristics, as well as the microorganisms themselves, have properties that change over time, location, and in certain conditions. In this regard, the problem of biofilm formation in dental practice is always relevant. It requires constant monitoring since high contamination of orthodontic materials can reduce the effectiveness of local anti-inflammatory therapy and cause relapses in caries and inflammatory diseases of the oral cavity. Adhesive properties, one of the key factors in forming the architectonics of biofilms, provide the virulence factors of microorganisms and are characterized by an increase in optical density, determining the duration and retrospectivity of diagnostic studies. This paper focuses on the isolation of clinical microbial isolates during aligner therapy and their ability to form biofilms. In the future, we plan to use the obtained strains of microorganisms to create an effective and safe biofilm-destroying agent. We aimed to study morphometric and densitometric indicators of biofilms of microorganisms persisting on aligners.}, } @article {pmid36660946, year = {2023}, author = {Liu, X and Xu, S and Chen, X and Kang, S and Liu, J and Jiang, Q and Zhang, S and Hao, L and Ran, H and Huang, W and Zhang, D}, title = {Synergistic effect of bovine cateslytin-loaded nanoparticles combined with ultrasound against Candida albicans biofilm.}, journal = {Future medicinal chemistry}, volume = {15}, number = {1}, pages = {43-55}, doi = {10.4155/fmc-2022-0062}, pmid = {36660946}, issn = {1756-8927}, mesh = {Animals ; Cattle ; *Candida albicans ; Reactive Oxygen Species ; Hemolysis ; Biofilms ; *Nanoparticles/chemistry ; RNA, Messenger ; Antifungal Agents/pharmacology ; }, abstract = {Purpose: To investigate the synergistic effect of bovine cateslytin-loaded nanoparticles (bCAT-NPs) combined with ultrasound against Candida albicans biofilm and uncover the underlying mechanism. Methods: bCAT-NPs were prepared by the double emulsion method, and toxicity was observed by the hemolysis ratio. The metabolic activity and viable cell biomass, morphology and membrane permeability of C. albicans biofilm were observed. The expression of ALS3 mRNA, the content of reactive oxygen species, was detected. Finally, bCAT structure was analyzed. Results & conclusion: The hemolysis ratio of the bCAT-NPs group was significantly lower than that of the bCAT group. bCAT-NPs combined with ultrasound significantly reduced biofilm metabolic activity, inhibited the formation of hyphae, decreased the expression of ALS3 mRNA and increased the intracellular reactive oxygen species content. In the in vivo experiments, the colony-forming units/ml in the ultrasound+bCAT-NPs group decreased, and a few planktonic fungal cells were observed.}, } @article {pmid36660364, year = {2023}, author = {Laulund, AS and Schwartz, FA and Christophersen, L and Kolpen, M and Østrup Jensen, P and Calum, H and Høiby, N and Thomsen, K and Moser, C}, title = {Hyperbaric oxygen therapy augments ciprofloxacin effect against Pseudomonas aeruginosa biofilm infected chronic wounds in a mouse model.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100100}, pmid = {36660364}, issn = {2590-2075}, abstract = {INTRODUCTION: Chronic wounds have a compromised microcirculation which leads to restricted gas exchange. The majority of these hypoxic wounds is infested with microorganisms congregating in biofilms which further hinders the antibiotic function. We speculate whether this process can be counteracted by hyperbaric oxygen therapy (HBOT).

METHODOLOGY: Twenty-eight BALB/c mice with third-degree burns were included in the analyses. Pseudomonas aeruginosa embedded in seaweed alginate beads was injected under the eschar to mimic a biofilm infected wound. Challenged mice were randomized to receive either 4 days with 1 x ciprofloxacin combined with 2 × 90 min HBOT at 2.8 standard atmosphere daily, 1 x ciprofloxacin as monotherapy or saline as placebo. The mice were clinically scored, and wound sizes were estimated by planimetry daily. Euthanasia was performed on day 8. Wounds were surgically removed in toto, homogenized and plated for quantitative bacteriology. Homogenate supernatants were used for cytokine analysis.

RESULTS: P. aeruginosa was present in all wounds at euthanasia. A significant lower bacterial load was seen in the HBOT group compared to either the monotherapy ciprofloxacin group (p = 0.0008), or the placebo group (p < 0.0001). IL-1β level was significantly lower in the HBOT group compared to the placebo group (p = 0.0007). Both treatment groups had higher osteopontin levels than the placebo group (p = 0.002 and p = 0.004). The same pattern was seen in the S100A9 analysis (p = 0.01 and p = 0.008), whereas no differences were detected between the S100A8, the VEGF or the MMP8 levels in the three groups.

CONCLUSION: These findings show that HBOT improves the bactericidal activity of ciprofloxacin against P. aeruginosa wound biofilm in vivo. HBOT in addition to ciprofloxacin also modulates the host response to a less inflammatory phenotype.}, } @article {pmid36658772, year = {2023}, author = {Mousavi, SM and Mousavi, SMA and Moeinizadeh, M and Aghajanidelavar, M and Rajabi, S and Mirshekar, M}, title = {Evaluation of biosynthesized silver nanoparticles effects on expression levels of virulence and biofilm-related genes of multidrug-resistant Klebsiella pneumoniae isolates.}, journal = {Journal of basic microbiology}, volume = {63}, number = {6}, pages = {632-645}, doi = {10.1002/jobm.202200612}, pmid = {36658772}, issn = {1521-4028}, mesh = {Humans ; Virulence/genetics ; Klebsiella pneumoniae ; Silver/pharmacology ; *Metal Nanoparticles ; Biofilms ; beta-Lactamases/genetics ; Anti-Bacterial Agents/pharmacology ; Microbial Sensitivity Tests ; *Klebsiella Infections/microbiology ; }, abstract = {The emergence of multidrug-resistant (MDR) strains of Klebsiella pneumoniae is associated with high morbidity and mortality due to limited treatment options. This study attempts to biologically synthesize silver nanoparticles (AgNPs) and investigate their effect on expression levels of virulence and biofilm-related genes in clinically isolated K. pneumoniae. In this study, biofilm formation ability, antibiotic resistance pattern, extended-spectrum β-lactamases (ESBLs), and carbapenemases production were investigated for 200 clinical isolates of K. pneumoniae using phenotypic methods. Polymerase chain reaction (PCR) was used to detect virulence and biofilm-related genes, ESBL-encoding genes, and carbapenem resistance genes. AgNPs were synthesized using the bio-reduction method. The antibacterial effects of AgNPs were investigated by microdilution broth. In addition, the cytotoxic effect of AgNPs on L929 fibroblast cell lines was determined. The effects of AgNPs on K. pneumoniae virulence and biofilm-related genes (fimH, rmpA, and mrkA) were determined using quantitative real-time PCR. Thirty percent of the isolates produced a strong biofilm. The highest and lowest levels of resistance were observed against amoxicillin/clavulanic acid (95.4%) and tigecycline (96%), respectively. About 31% of isolates were considered positive for carbapenemases, and 75% of the isolates produced an ESBLs enzyme. Different frequencies of mentioned genes were observed. The synthesized AgNPs had a spherical morphology and varied in size. AgNPs inhibited the growth of MDR K. pneumoniae at 128 µg/ml. In addition, AgNPs downregulated the expression of fimH, rmpA, and mrkA genes by 10, 7, and 14-fold, respectively (p < 0.05), also exerted no cytotoxic effect on L929 fibroblast cell lines. It was revealed that AgNPs lead to a decrease in expression levels of virulence and biofilm-related genes; therefore, it was concluded that AgNPs had an excellent antibacterial effect on MDR K. pneumoniae.}, } @article {pmid36658553, year = {2023}, author = {Wang, J and Geng, T and Wang, Y and Yuan, C and Wang, P}, title = {Efficacy of antibacterial agents combined with erbium laser and photodynamic therapy in reducing titanium biofilm vitality: an in vitro study.}, journal = {BMC oral health}, volume = {23}, number = {1}, pages = {32}, pmid = {36658553}, issn = {1472-6831}, mesh = {Humans ; Anti-Bacterial Agents ; *Lasers, Solid-State/therapeutic use ; Titanium/therapeutic use ; Erbium ; *Photochemotherapy/methods ; Biofilms ; Surface Properties ; *Dental Implants/microbiology ; }, abstract = {BACKGROUND AND OBJECTIVE: The emergence of peri-implant diseases has prompted various methods for decontaminating the implant surface. This study compared the effectiveness of three different approaches, chlorhexidine digluconate (CHX) combined with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser, photodynamic therapy (PDT), and CHX only, for reducing biofilm vitality from implant-like titanium surfaces.

The study involved eight volunteers, each receiving a custom mouth device containing eight titanium discs. The volunteers were requested to wear the device for 72 h for biofilm development. Fluorescence microscopy was used to evaluate the remaining biofilm with a two-component nucleic acid dye kit. The vital residual biofilm was quantified as a percentage of the surface area using image analysis software. Sixty-four titanium discs were assigned randomly to one of four treatment groups.

RESULTS: The percentage of titanium disc area covered by vital residual biofilm was 43.9% (7.7%), 32.2% (7.0%), 56.6% (3.6%), and 73.2% (7.8%) in the PDT, Er:YAG, CHX, and control groups, respectively (mean (SD)). Compared to the control group, the treatment groups showed significant differences in the area covered by residual biofilm (P < 0.001). CHX combined with Er:YAG laser treatment was superior to CHX combined with PDT, and CHX only was better than the control.

CONCLUSION: Within the current in vitro model's limitations, CHX combined with Er:YAG laser treatment is a valid method to reduce biofilm vitality on titanium discs.}, } @article {pmid36658257, year = {2023}, author = {Agrawal, S and Tipre, D and Dave, SR}, title = {Biotreatment of azo dye containing textile industry effluent by a developed bacterial consortium immobilised on brick pieces in an indigenously designed packed bed biofilm reactor.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {3}, pages = {83}, pmid = {36658257}, issn = {1573-0972}, mesh = {*Coloring Agents/metabolism ; *Textile Industry ; Azo Compounds/metabolism ; Bioreactors/microbiology ; Bacteria/genetics/metabolism ; Biodegradation, Environmental ; Biofilms ; Industrial Waste ; }, abstract = {This study highlights the development of a lab-scale, indigenously designed; Packed-Bed Biofilm Reactor (PBBR) packed with brick pieces. The developed biofilm in the reactor was used for the decolourisation and biodegradation of the textile industry effluent. The PBBR was continuously operated for 264 days, during which 301 cycles of batch and continuous treatment were operated. In batch mode under optimised conditions, more than 99% dye decolourisation and ≥ 92% COD reduction were achieved in 6 h of contact time upon supplementation of effluent with 0.25 g L[-1] glucose, 0.25 g L[-1] urea, and 0.1 g L[-1] phosphates. A decolourisation rate of 133.94 ADMI units h[-1] was achieved in the process. PBBR, when operated in continuous mode, showed ≥ 95% and ≥ 92% reduction in ADMI and COD values. Subsequent aeration and passage through the charcoal reactor assisted in achieving a ≥ 96% reduction in COD and ADMI values. An overall increase of 81% in dye-laden effluent decolourisation rate, from 62 to 262 mg L[-1] h[-1], was observed upon increasing the flow rate from 18 to 210 mL h[-1]. Dye biodegradation was determined by UV-Vis and FTIR spectroscopy and toxicity study. SEM analysis showed the morphology of the attached-growth biofilm.}, } @article {pmid36658182, year = {2023}, author = {Pakkulnan, R and Thonglao, N and Chareonsudjai, S}, title = {DNase I and chitosan enhance efficacy of ceftazidime to eradicate Burkholderia pseudomallei biofilm cells.}, journal = {Scientific reports}, volume = {13}, number = {1}, pages = {1059}, pmid = {36658182}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Burkholderia pseudomallei/genetics ; Ceftazidime/pharmacology/therapeutic use ; *Chitosan/pharmacology/therapeutic use ; Deoxyribonuclease I/pharmacology ; *Melioidosis/drug therapy ; Microbial Sensitivity Tests ; }, abstract = {Biofilm-associated Burkholderia pseudomallei infection contributes to antibiotic resistance and relapse of melioidosis. Burkholderia pseudomallei biofilm matrix contains extracellular DNA (eDNA) that is crucial for biofilm establishment. However, the contribution of eDNA to antibiotic resistance by B. pseudomallei remains unclear. In this study, we first demonstrated in vitro that DNase I with the administration of ceftazidime (CAZ) at 24 h considerably inhibited the 2-day biofilm formation and reduced the number of viable biofilm cells of clinical B. pseudomallei isolates compared to biofilm treated with CAZ alone. A 3-4 log reduction in numbers of viable cells embedded in the 2-day biofilm was observed when CAZ was combined with DNase I. Confocal laser-scanning microscope visualization emphasized the competence of DNase I followed by CAZ supplementation to significantly limit B. pseudomallei biofilm development and to eradicate viable embedded B. pseudomallei biofilm cells. Furthermore, DNase I supplemented with chitosan (CS) linked with CAZ (CS/CAZ) significantly eradicated shedding planktonic and biofilm cells. These findings indicated that DNase I effectively degraded eDNA leading to biofilm inhibition and dispersion, subsequently allowing CAZ and CS/CAZ to eradicate both shedding planktonic and embedded biofilm cells. These findings provide efficient strategies to interrupt biofilm formation and improve antibiotic susceptibility of biofilm-associated infections.}, } @article {pmid36657584, year = {2023}, author = {Vladimir, M and Tatiana, R and Evgeniy, S and Veerasingam, S and Bagaev, A}, title = {Vertical and seasonal variations in biofilm formation on plastic substrates in coastal waters of the Black Sea.}, journal = {Chemosphere}, volume = {317}, number = {}, pages = {137843}, doi = {10.1016/j.chemosphere.2023.137843}, pmid = {36657584}, issn = {1879-1298}, mesh = {*Plastics/chemistry ; Seasons ; Black Sea ; *Biofilms ; Water ; Environmental Monitoring ; }, abstract = {Plastic contamination of the marine environment is an increasing concern worldwide. Therefore, it is important to understand the kinetics of biofilms on plastics to study their behavior, fate, and transport pathways in the ocean. In this study, the vertical and seasonal variations in biofouling formation on transparent polyethylene terephthalate (PET) plastic fragments in the Southwest Crimea coastal waters of the Black Sea were investigated. Biofilms were identified in the transient light as 'dark spots' on the plastic surface, for which the numbers, size, and area were measured using specialized software. The rate of biofouling in the surface water layer was lower than those found in the middle and near-bottom water column, which could be due to a damaging effect of turbulent mixing on the biofilm. The highest rates of biofouling and diverse community were observed during the summer. The epibiotic assembly was represented by diatoms (11 taxa), dinoflagellates (3 taxa), green algae, filamentous cyanobacteria, small flagellates, and ciliates. Significant differences between the biofouling rates observed in different seasons made it difficult to estimate the period of time the plastic substrate has been in the marine environment. It was proposed to use the green alga Phycopeltis arundinacea (Montgn) De Tender et al., 2015 as a bioindicator to study the age of the biofouling community. Discoid thalli were identified at all stages of colonization of the plastic fragments in different seasons. Results obtained in this study demonstrate that biofouling organisms may be good model organisms in revealing age of biofilm formation and longevity of plastic debris in the ocean. Consequently, it is proposed that such biofouling organisms could be used as target species to monitor the biodegradation of plastic debris.}, } @article {pmid36657551, year = {2023}, author = {Zhao, D and Li, X and Xu, M and Jiao, Y and Liu, H and Xiao, X and Zhao, H}, title = {Preparations of antibacterial yellow-green-fluorescent carbon dots and carbon dots-lysozyme complex and their applications in bacterial imaging and bacteria/biofilm inhibition/clearance.}, journal = {International journal of biological macromolecules}, volume = {231}, number = {}, pages = {123303}, doi = {10.1016/j.ijbiomac.2023.123303}, pmid = {36657551}, issn = {1879-0003}, mesh = {Humans ; Staphylococcus aureus ; Carbon/chemistry ; Muramidase/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Bacteria ; *Quantum Dots/chemistry ; *Staphylococcal Infections ; Fluorescent Dyes/chemistry ; }, abstract = {The preparation of functional long-wavelength-emitting nanomaterials and the researches on their applications in antibacterial and antibiofilm fields have important significance. This paper reports the preparation of yellow-green-fluorescent and high- quantum yield carbon dots (4-ACDs) with 4-aminosalicylic acid and polyethylene imine as raw materials through one-step route, and the impacts of raw material structure and the reaction conditions upon the optical properties of the products have been investigated. 4-ACDs exhibit excellent broad-spectrum antibacterial activity, and their good biocompatibility ensures them as ideal fluorescent nano-probe for cell imaging. However, 4-ACDs could not effectively eliminate the biofilm of Staphylococcus aureus (S. aureus). CDs-LZM complex was prepared through the coupling between 4-ACDs and lysozyme (LZM) and the complex showed strong antibacterial activity against Gram-positive bacteria, particularly with MIC against S. aureus at 5 μg mL[-1]. Besides, CDs-LZM showed excellent ability against the biofilm of S. aureus. At the concentration of 60 μg mL[-1], its inhibition rate against the growth of biofilm was 86 %, and elimination rate against biofilm reached 76 %. CDs-LZM exhibited obvious antibiofilm ability through removing extracellular matrix of biofilm, greatly reducing the thickness of biofilm under confocal microscopy. The application of novel long-wavelength-emitting nanomaterial in eliminating pathogenic bacteria is of great significance.}, } @article {pmid36657162, year = {2023}, author = {Lee, CW and Lin, ZC and Chiang, YC and Li, SY and Ciou, JJ and Liu, KW and Lin, YC and Huang, BJ and Peng, KT and Fang, ML and Lin, TE and Liao, MY and Lai, CH}, title = {AuAg nanocomposites suppress biofilm-induced inflammation in human osteoblasts.}, journal = {Nanotechnology}, volume = {34}, number = {16}, pages = {}, doi = {10.1088/1361-6528/acb4a1}, pmid = {36657162}, issn = {1361-6528}, mesh = {Humans ; Gold/pharmacology ; *Metal Nanoparticles/chemistry ; Staphylococcus aureus ; Reactive Oxygen Species/metabolism ; Anti-Bacterial Agents/pharmacology/chemistry ; Bacteria ; *Nanocomposites/chemistry ; Biofilms ; Inflammation/drug therapy ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus aureus (S. aureus)forms biofilm that causes periprosthetic joint infections and osteomyelitis (OM) which are the intractable health problems in clinics. The silver-containing nanoparticles (AgNPs) are antibacterial nanomaterials with less cytotoxicity than the classic Ag compounds. Likewise, gold nanoparticles (AuNPs) have also been demonstrated as excellent nanomaterials for medical applications. Previous studies have showed that both AgNPs and AuNPs have anti-microbial or anti-inflammatory properties. We have developed a novel green chemistry that could generate the AuAg nanocomposites, through the reduction of tannic acid (TNA). The bioactivity of the nanocomposites was investigated inS. aureusbiofilm-exposed human osteoblast cells (hFOB1.19). The current synthesis method is a simple, low-cost, eco-friendly, and green chemistry approach. Our results showed that the AuAg nanocomposites were biocompatible with low cell toxicity, and did not induce cell apoptosis nor necrosis in hFOB1.19 cells. Moreover, AuAg nanocomposites could effectively inhibited the accumulation of reactive oxygen species (ROS) in mitochondria and in rest of cellular compartments after exposing to bacterial biofilm (by reducing 0.78, 0.77-fold in the cell and mitochondria, respectively). AuAg nanocomposites also suppressed ROS-triggered inflammatory protein expression via MAPKs and Akt pathways. The current data suggest that AuAg nanocomposites have the potential to be a good therapeutic agent in treating inflammation in bacteria-infected bone diseases.}, } @article {pmid36656902, year = {2023}, author = {Lee, H and Im, H and Hwang, SH and Ko, D and Choi, SH}, title = {Two novel genes identified by large-scale transcriptomic analysis are essential for biofilm and rugose colony development of Vibrio vulnificus.}, journal = {PLoS pathogens}, volume = {19}, number = {1}, pages = {e1011064}, pmid = {36656902}, issn = {1553-7374}, mesh = {Humans ; *Vibrio vulnificus ; Transcriptome ; Biofilms ; *Vibrio ; Genes, Bacterial ; Gene Expression Regulation, Bacterial ; }, abstract = {Many pathogenic bacteria form biofilms to survive under environmental stresses and host immune defenses. Differential expression (DE) analysis of the genes in biofilm and planktonic cells under a single condition, however, has limitations to identify the genes essential for biofilm formation. Independent component analysis (ICA), a machine learning algorithm, was adopted to comprehensively identify the biofilm genes of Vibrio vulnificus, a fulminating human pathogen, in this study. ICA analyzed the large-scale transcriptome data of V. vulnificus cells under various biofilm and planktonic conditions and then identified a total of 72 sets of independently co-regulated genes, iModulons. Among the three iModulons specifically activated in biofilm cells, BrpT-iModulon mainly consisted of known genes of the regulon of BrpT, a transcriptional regulator controlling biofilm formation of V. vulnificus. Interestingly, the BrpT-iModulon additionally contained two novel genes, VV1_3061 and VV2_1694, designated as cabH and brpN, respectively. cabH and brpN were shared in other Vibrio species and not yet identified by DE analyses. Genetic and biochemical analyses revealed that cabH and brpN are directly up-regulated by BrpT. The deletion of cabH and brpN impaired the robust biofilm and rugose colony formation. CabH, structurally similar to the previously known calcium-binding matrix protein CabA, was essential for attachment to the surface. BrpN, carrying an acyltransferase-3 domain as observed in BrpL, played an important role in exopolysaccharide production. Altogether, ICA identified two novel genes, cabH and brpN, which are regulated by BrpT and essential for the development of robust biofilms and rugose colonies of V. vulnificus.}, } @article {pmid36656746, year = {2023}, author = {Brooks, JR and Chonko, DJ and Pigott, M and Sullivan, AC and Moore, K and Stoodley, P}, title = {Mapping bacterial biofilm on explanted orthopedic hardware: An analysis of 14 consecutive cases.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {131}, number = {4}, pages = {170-179}, pmid = {36656746}, issn = {1600-0463}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Prosthesis-Related Infections/diagnosis/microbiology ; RNA, Ribosomal, 16S/genetics ; Biofilms ; Bacteria/genetics ; Anti-Bacterial Agents/therapeutic use ; }, abstract = {Hardware implanted during primary total joint arthroplasty carries a serious risk for periprosthetic joint infection (PJI). The formation of bacterial biofilms, which are highly tolerant of antibiotics and host immunity, is recognized as being a major barrier to treatment. It is not known whether some components and their surface features are more prone to biofilm than others. This study attempted to map biofilm on different components and features of orthopedic hardware recovered during revision. Implant surface culture (ISC) was used on 53 components from 14 hip and knee revisions. ISC achieves a thin agar coating over components, followed by incubation and observation for colony outgrowth over 9 days. Recovered organisms were identified by selective culture and 16s rRNA sequencing. Outcomes were compared with clinical culturing and PJI diagnosis based on 2013 Musculoskeletal Infection Society criteria. ISC paralleled clinical culturing with a sensitivity of 100% and a specificity of 57.1%. When compared to Musculoskeletal Infection Society criteria, sensitivity remained at 100% while specificity was 80%. Biofilm accumulation was patchy and heterogeneous throughout different prostheses, though notably the non-articulating surfaces between the tibial tray and polyethylene insert showed consistent growth. On individual components, ridges and edges consistently harbored biofilm, while growth elsewhere was case dependent. ISC successfully identified microbial growth with high sensitivity while also revealing that biofilm growth was commonly localized to particular locations. Understanding where biofilm formation occurs most often on implanted hardware will help guide debridement, retention choices, and implant design.}, } @article {pmid36656007, year = {2023}, author = {Goh, YF and Røder, HL and Chan, SH and Ismail, MH and Madsen, JS and Lee, KWK and Sørensen, SJ and Givskov, M and Burmølle, M and Rice, SA and McDougald, D}, title = {Associational Resistance to Predation by Protists in a Mixed Species Biofilm.}, journal = {Applied and environmental microbiology}, volume = {89}, number = {2}, pages = {e0174122}, pmid = {36656007}, issn = {1098-5336}, mesh = {Animals ; *Predatory Behavior ; *Biofilms ; Quorum Sensing ; Eukaryota ; Pseudomonas aeruginosa/physiology ; }, abstract = {Mixed species biofilms exhibit increased tolerance to numerous stresses compared to single species biofilms. The aim of this study was to examine the effect of grazing by the heterotrophic protist, Tetrahymena pyriformis, on a mixed species biofilm consisting of Pseudomonas aeruginosa, Pseudomonas protegens, and Klebsiella pneumoniae. Protozoan grazing significantly reduced the single species K. pneumoniae biofilm, and the single species P. protegens biofilm was also sensitive to grazing. In contrast, P. aeruginosa biofilms were resistant to predation. This resistance protected the otherwise sensitive members of the mixed species biofilm consortium. Rhamnolipids produced by P. aeruginosa were shown to be the primary toxic factor for T. pyriformis. However, a rhamnolipid-deficient mutant of P. aeruginosa (P. aeruginosa ΔrhlAB) maintained grazing resistance in the biofilm, suggesting the presence of at least one additional protective mechanism. P. aeruginosa with a deleted gene encoding the type III secretion system also resisted grazing. A transposon library was generated in the ΔrhlAB mutant to identify the additional factor involved in community biofilm protection. Results indicated that the Pseudomonas Quinolone Signal (PQS), a quorum sensing signaling molecule, was likely responsible for this effect. We confirmed this observation by showing that double mutants of ΔrhlAB and genes in the PQS biosynthetic operon lost grazing protection. We also showed that PQS was directly toxic to T. pyriformis. This study demonstrates that residing in a mixed species biofilm can be an advantageous strategy for grazing sensitive bacterial species, as P. aeruginosa confers community protection from protozoan grazing through multiple mechanisms. IMPORTANCE Biofilms have been shown to protect bacterial cells from predation by protists. Biofilm studies have traditionally used single species systems, which have provided information on the mechanisms and regulation of biofilm formation and dispersal, and the effects of predation on these biofilms. However, biofilms in nature are comprised of multiple species. To better understand how multispecies biofilms are impacted by predation, a model mixed-species biofilm was here exposed to protozoan predation. We show that the grazing sensitive strains K. pneumonia and P. protogens gained associational resistance from the grazing resistant P. aeruginosa. Resistance was due to the secretion of rhamnolipids and quorum sensing molecule PQS. This work highlights the importance of using mixed species systems.}, } @article {pmid36655713, year = {2023}, author = {Römling, U}, title = {Is biofilm formation intrinsic to the origin of life?.}, journal = {Environmental microbiology}, volume = {25}, number = {1}, pages = {26-39}, pmid = {36655713}, issn = {1462-2920}, mesh = {Humans ; *Biofilms ; }, abstract = {Biofilms are multicellular, often surface-associated, communities of autonomous cells. Their formation is the natural mode of growth of up to 80% of microorganisms living on this planet. Biofilms refractory towards antimicrobial agents and the actions of the immune system due to their tolerance against multiple environmental stresses. But how did biofilm formation arise? Here, I argue that the biofilm lifestyle has its foundation already in the fundamental, surface-triggered chemical reactions and energy preserving mechanisms that enabled the development of life on earth. Subsequently, prototypical biofilm formation has evolved and diversified concomitantly in composition, cell morphology and regulation with the expansion of prokaryotic organisms and their radiation by occupation of diverse ecological niches. This ancient origin of biofilm formation thus mirrors the harnessing environmental conditions that have been the rule rather than the exception in microbial life. The subsequent emergence of the association of microbes, including recent human pathogens, with higher organisms can be considered as the entry into a nutritional and largely stress-protecting heaven. Nevertheless, basic mechanisms of biofilm formation have surprisingly been conserved and refunctionalized to promote sustained survival in new environments.}, } @article {pmid36655001, year = {2023}, author = {Johnston, W and Ware, A and Kuiters, WF and Delaney, C and Brown, JL and Hagen, S and Corcoran, D and Cummings, M and Ramage, G and Kean, R}, title = {In vitro bacterial vaginosis biofilm community manipulation using endolysin therapy.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100101}, pmid = {36655001}, issn = {2590-2075}, abstract = {Bacterial vaginosis (BV) affects approximately 26% of women of childbearing age globally, presenting with 3-5 times increased risk of miscarriage and two-fold risk of pre-term birth. Antibiotics (metronidazole and clindamycin) are typically employed to treat BV; however the success rate is low due to the formation of recalcitrant polymicrobial biofilms. As a novel therapeutic, promising results have been obtained in vitro using Gardnerella endolysins, although to date their efficacy has only been demonstrated against simple biofilm models. In this study, a four-species biofilm was developed consisting of Gardnerella vaginalis, Fannyhessea vaginae, Prevotella bivia and Mobiluncus curtisii. Biofilms were grown in NYC III broth and treated using antibiotics and an anti-Gardnerella endolysin (CCB7.1) for 24 h. Biofilm composition, viability and structure were assessed using colony counts, live/dead qPCR and scanning electron microscopy. All species colonised biofilms to varying degrees, with G. vaginalis being the most abundant. Biofilm composition remained largely unchanged when challenged with escalated concentrations of conventional antibiotics. A Gardnerella-targeted endolysin candidate (CCB7.1) showed efficacy against several Gardnerella species planktonically, and significantly reduced viable G. vaginalis within polymicrobial biofilms at 1 to 4X pMIC (p < 0.05 vs. vehicle control). Collectively, this study highlights the resilience of biofilm-embedded pathogens against the currently used antibiotics and provides a polymicrobial model that allows for more effective pre-clinical screening of BV therapies. The Gardnerella-specific endolysin CCB7.1 demonstrated significant activity against G. vaginalis within polymicrobial biofilms, altering the overall community dynamic and composition.}, } @article {pmid36651814, year = {2023}, author = {Zhang, X and Zheng, L and Lu, Z and Zhou, L and Meng, F and Shi, C and Bie, X}, title = {Biochemical and molecular regulatory mechanism of the pgpH gene on biofilm formation in Listeria monocytogenes.}, journal = {Journal of applied microbiology}, volume = {134}, number = {2}, pages = {}, doi = {10.1093/jambio/lxac086}, pmid = {36651814}, issn = {1365-2672}, support = {32272295//National Natural Science Foundation of China/ ; }, mesh = {*Biofilms ; *Listeria monocytogenes/physiology ; Gene Deletion ; Bacterial Proteins/genetics/metabolism ; }, abstract = {AIMS: PgpH gene has an important regulatory role on bacterial physiological activity, but studies on its regulation mechanism on biofilm formation of Listeria monocytogenes are lacking. Our aim was to investigate the effect of pgpH gene deletion on biofilm formation in L. monocytogenes.

METHODS AND RESULTS: The ΔpgpH deletion strain of L. monocytogenes LMB 33  426 was constructed by homologous recombination. Deletion of the pgpH gene resulted in a significant reduction in biofilm formation. The swimming ability of the ΔpgpH strain on semisolid plates was unchanged compared to the wild-type strain (WT), and the auto-aggregation capacity of L. monocytogenes was decreased. RNA-seq showed that ΔpgpH resulted in the differential expression of 2357 genes compared to WT. pgpH inactivation resulted in the significant downregulation of the cell wall formation-related genes dltC, dltD, walK, and walR and the flagellar assembly related genes fliG and motB.

CONCLUSIONS: This study shows that the deletion of pgpH gene regulates biofilm formation and auto-aggregation ability of L. monocytogenes by affecting the expression of flagellar assembly and cell wall related genes. pgpH has a global regulatory effect on biofilm formation in L. monocytogenes.}, } @article {pmid36651450, year = {2023}, author = {Barbosa, DHX and Gondim, CR and Silva-Henriques, MQ and Soares, CS and Alves, DN and Santos, SG and Castro, RD}, title = {Coriandrum sativum L. essential oil obtained from organic culture shows antifungal activity against planktonic and multi-biofilm Candida.}, journal = {Brazilian journal of biology = Revista brasleira de biologia}, volume = {83}, number = {}, pages = {e264875}, doi = {10.1590/1519-6984.264875}, pmid = {36651450}, issn = {1678-4375}, mesh = {Antifungal Agents/pharmacology ; Candida ; *Coriandrum ; Plankton ; *Oils, Volatile/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {This study aimed to analyze the phytochemical profile of essential oil obtained from the leaves of Coriandrum sativum L., and its antifungal activity against Candida spp. The research consisted of an in vitro study including collecting the vegetable product, analysis of its macronutrients, extraction, and chemical analysis of the essential oil, and assaying antifungal activity through minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), with growth inhibition kinetics, and the product's effects on multi-species Candida biofilm. Nitrogen (47.08 g Kg-1), phosphorus (5.3 g Kg-1) and potassium (50.46 g Kg-1) levels were within the normal range. The major constituents were octanal, decanal, dec-(2E)-enal, and dodecanal. The MIC and MFC of the product evaluated against 11 tested Candida strains ranged from 31.25 to 250 μg/mL. There was inhibition of fungal growth during 24 hours of exposure at the 3 concentrations tested (250, 125, and 62.5 μg/mL). The concentration of 80 mg/mL promoted the greatest reduction in multispecies biofilm (70% reduction in biofilm). Coriandrum sativum L. essential oil extract is principally constituted of alcohols and aldehydes and presents fungicidal activity against Candida spp. in its in planktonic and biofilm forms.}, } @article {pmid36649516, year = {2023}, author = {Mohammadinejat, M and Sepahi, AA and Alipour, E}, title = {Antibacterial and Anti-Biofilm Activities of Silver Nano Particles Conjugated to Chitosan Against Multi-Drug Resistant Bacteria.}, journal = {Clinical laboratory}, volume = {69}, number = {1}, pages = {}, doi = {10.7754/Clin.Lab.2022.220315}, pmid = {36649516}, issn = {1433-6510}, mesh = {Humans ; Silver/pharmacology ; *Chitosan/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Iran ; Anti-Bacterial Agents/pharmacology ; Bacteria ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Nowadays, most of the traditional and conventional antibiotics are not effective against drug resistant bacterial strains. The emergence and spread of drug resistant bacterial cells calls for new therapeutic agents and strategies to control and treat the infections caused by these bacteria. In this regard, the application of nano-technology in medicine is an interesting approach. Therefore, the aim of this study was to evaluate the antibacterial and anti-biofilm activities of Ag Np conjugated to chitosan against multidrug resistant isolates of Staphylococcus aureus and Acinetobacter baumannii.

METHODS: Synthesis of the Ag Np and chitosan Np were performed according to the Turkevich and Ionic gelation methods, respectively. Then conjugation of nanoparticles was carried out by standard method. FTR analysis and transmission electron microscopy were used for validation of nanoparticle conjugation. Twenty clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and 20 clinical isolates of carbapenem resistant Acinetobacter baumannii (CRAB) were obtained from the microbial bank of Imam Khomeini hospital of Tehran, Iran. MIC values of the nanoparticles alone and in conjugation were determined using the microbroth dilution method. Then, fractional inhibitory concentration of agents was concluded by standard method. Finally, anti-biofilm activities of the conjugated Ag Np-chitosan at sub-MIC concentrations was tested against bacterial isolates.

RESULTS: Synthesis of Ag Np resulted in the formation of nanoparticles with 10 nm dimensions. MIC90 of the chitosan, Ag Np and their conjugated form were respectively 64, 16, and 8 μg/mL against CRAB isolates. Also, MIC90 of the tested agents, in the same order as mentioned above, were 32, 16, and 4 μg/mL against MRSA. Combination of the agents had additive (0.625) and synergistic (0.375) effects against CRAB and MRSA. Ability of biofilm formation was dramatically reduced by ¼ MIC concentration (2 μg/mL) against the CRAB and ½ MIC concentration (2 μg/mL) in the case of the MRSA isolates.

CONCLUSIONS: Ag Np-chitosan conjugation, an ideal alternative for ineffective antibiotics, exhibits great antibacterial and anti-biofilm effects against CRAB and MRSA isolates.}, } @article {pmid36649038, year = {2022}, author = {Whelan, S and O'Grady, MC and Corcoran, GD and Finn, K and Lucey, B}, title = {Effect of Sub-Inhibitory Concentrations of Nitrofurantoin, Ciprofloxacin, and Trimethoprim on In Vitro Biofilm Formation in Uropathogenic Escherichia coli (UPEC).}, journal = {Medical sciences (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {36649038}, issn = {2076-3271}, mesh = {Humans ; Nitrofurantoin/pharmacology ; Ciprofloxacin/pharmacology ; *Uropathogenic Escherichia coli ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Urinary Tract Infections/drug therapy ; Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology ; Biofilms ; }, abstract = {The purpose of this study was to determine the effect of sublethal concentrations of nitrofurantoin, ciprofloxacin, and trimethoprim on biofilm formation in 57 uropathogenic Escherichia coli strains (UPEC). The minimum inhibitory concentration of nitrofurantoin, ciprofloxacin, and trimethoprim was determined and the biofilm formation for each isolate with and without sub-lethal concentrations of each antibiotic was then quantified. The statistical significance of changes in biofilm formation was ascertained by way of a Dunnett's test. A total of 22.8% of strains were induced to form stronger biofilms by nitrofurantoin, 12% by ciprofloxacin, and 19% by trimethoprim; conversely 36.8% of strains had inhibited biofilm formation with nitrofurantoin, 52.6% with ciprofloxacin, and 38.5% with trimethoprim. A key finding was that even in cases where the isolate was resistant to an antibiotic as defined by EUCAST, many were induced to form a stronger biofilm when grown with sub-MIC concentrations of antibiotics, especially trimethoprim, where six of the 22 trimethoprim resistant strains were induced to form stronger biofilms. These findings suggest that the use of empirical treatment with trimethoprim without first establishing susceptibility may in fact potentiate infection in cases where a patient who is suffering from a urinary tract infection (UTI) caused by trimethoprim resistant UPEC is administered trimethoprim. This emphasizes the need for laboratory-guided treatment of UTI.}, } @article {pmid36648441, year = {2023}, author = {Pezolt, C and Karau, A and Schobert, R and Schrey, H}, title = {Syntheses and Biofilm Reducing Effects of l-Dopa-Derived Analogues of the Fungal Macrocidins A and Z.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {29}, number = {21}, pages = {e202203647}, doi = {10.1002/chem.202203647}, pmid = {36648441}, issn = {1521-3765}, support = {ZF4514501MD7//Bundesministerium für Wirtschaft und Energie/ ; }, mesh = {*Levodopa ; *Biofilms ; Structure-Activity Relationship ; Anti-Bacterial Agents/pharmacology ; Tyrosine ; }, abstract = {Four analogues of the fungal metabolites macrocidin A and Z, featuring [13]para- or [13]metacyclophanes, were synthesised from fully and orthogonally protected l-dopa instead of l-tyrosine. They were tested for antibiotic activities and for effects on the growth and persistence of microbial biofilms. Tentative structure-activity relationships and distinct differences when compared with the natural lead compounds were identified.}, } @article {pmid36645660, year = {2022}, author = {Myntti, MF and Stevenson, P and Porral, D and Hayes, VY}, title = {The effect of a biofilm-disrupting wound gel vs. a broad-spectrum antimicrobial ointment on a chronic wound microbiome: a secondary analysis associating clinical and laboratory findings.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {34}, number = {12}, pages = {E141-E146}, doi = {10.25270/wnds/21113}, pmid = {36645660}, issn = {1943-2704}, mesh = {Prospective Studies ; Ointments/pharmacology ; *Anti-Infective Agents/pharmacology ; Wound Healing ; Biofilms ; }, abstract = {INTRODUCTION: Advancement in wound bioburden diagnostics continues to evolve highlighting the need to link laboratory findings to clinical practice.

OBJECTIVE: This study aims to determine if laboratory data from a previously published study supports a correlation between use of a novel biofilm-disrupting wound gel and lower bacterial bioburden, wound size reduction, and improved healing.

MATERIALS AND METHODS: This is a secondary data analysis of a multicenter, prospective, randomized, open-label clinical trial performed from September 2014 through March 2016. The trial compares treatment outcomes of standard of care either with a wound gel (experimental) or triple-antibiotic maximum-strength ointment (control) looking at differences in bioburden measured at time zero (baseline) and after 4 weeks of treatment. Quantitative real-time PCR testing for bacteria and fungi, including testing for resistance factors to vancomycin and methicillin or using proprietary genetic sequencing, was used for analysis.

RESULTS: Low or medium bacterial load at baseline correlated to an average reduction in wound size of 40% and 24%, respectively, whereas there was a 19% increase in size among wounds with a high bioburden.

CONCLUSION: Reducing wound bioburden could result in a clinically relevant change in the healing trajectory. In this study, wound size reduction and increased healing percentages were superior in the experimental group.}, } @article {pmid36645278, year = {2023}, author = {Liu, J and Chang, Z and Chang, X and Li, J and Glebe, U and Jia, AQ}, title = {Combination of 2-tert-Butyl-1,4-Benzoquinone (TBQ) and ZnO Nanoparticles, a New Strategy To Inhibit Biofilm Formation and Virulence Factors of Chromobacterium violaceum.}, journal = {mSphere}, volume = {8}, number = {1}, pages = {e0059722}, pmid = {36645278}, issn = {2379-5042}, mesh = {Animals ; *Zinc Oxide/pharmacology ; Virulence Factors/genetics ; Caenorhabditis elegans ; Quorum Sensing/genetics ; Biofilms ; Bacteria ; }, abstract = {Drug-resistant bacteria have been raising serious social problems. Bacterial biofilms and different virulence factors are the main reasons for persistent infections. As a conditioned pathogen, Chromobacterium violaceum has evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development, contributing to multidrug resistance. However, there are few therapies to combat drug-resistant bacteria. Quorum sensing (QS) inhibitors (QSIs) are a promising strategy to solve antibiotic resistance. Our previous work suggested that 2-tert-butyl-1,4-benzoquinone (TBQ) is a potent QSI. In this study, the combination of zinc oxide nanoparticles (ZnO-NPs) and TBQ (ZnO-TBQ) was investigated for the treatment of Chromobacterium violaceum ATCC 12472 infection. ZnO-NPs attach to cell walls or biofilms, and the local dissolution of ZnO-NPs can lead to increased Zn[2+] concentrations, which could destroy metal homeostasis, corresponding to disturbances in amino acid metabolism and nucleic acid metabolism. ZnO-NPs significantly improved the efficiency of TBQ in inhibiting the QS-related virulence factors and biofilm formation of C. violaceum ATCC 12472. ZnO-TBQ effectively reduces the expression of genes related to QS, which is conducive to limiting the infectivity of C. violaceum ATCC 12472. Caenorhabditis elegans nematodes treated with ZnO-TBQ presented a significant improvement in the survival rate by 46.7%. Overall, the combination of ZnO-NPs and TBQ offers a new strategy to attenuate virulence factors and biofilm formation synergistically in some drug-resistant bacteria. IMPORTANCE The combination of ZnO-NPs and TBQ (ZnO-TBQ) can compete with the inducer N-decanoyl-homoserine lactone (C10-HSL) by binding to CviR and downregulate genes related to the CviI/CviR system to interrupt the QS system of C. violaceum ATCC 12472. The downstream genes responding to cviR were also downregulated so that virulence factors and biofilm formation were inhibited. Furthermore, ZnO-TBQ presents multiple metabolic disturbances in C. violaceum ATCC 12472, which results in the reduced multidrug resistance and pathogenicity of C. violaceum ATCC 12472. In an in vivo assay, C. elegans nematodes treated with ZnO-TBQ presented a significant improvement in the survival rate by 46.7% by limiting the infectivity of C. violaceum ATCC 12472. In addition, ZnO-TBQ inhibited the generation of virulence factors and biofilm formation 2-fold compared to either ZnO-NPs or TBQ alone. The combination of ZnO-NPs with TBQ offers a potent synergistic strategy to reduce multidrug resistance and pathogenicity.}, } @article {pmid36644897, year = {2023}, author = {He, Z and Xu, X and Wang, C and Li, Y and Dong, B and Li, S and Zeng, J}, title = {Effect of Panax quinquefolius extract on Mycobacterium abscessus biofilm formation.}, journal = {Biofouling}, volume = {39}, number = {1}, pages = {24-35}, doi = {10.1080/08927014.2023.2166405}, pmid = {36644897}, issn = {1029-2454}, mesh = {*Mycobacterium abscessus ; *Panax ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Bacteria ; Plankton ; Plant Extracts/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Mycobacterium abscessus (M. abscessus) can exist either as planktonic bacteria or as a biofilm. Biofilm formation is one of the important causes of conversion to resistance to antibiotics of bacteria that were previously sensitive when in their planktonic form, resulting in infections difficult to manage. Panax quinquefolius and its active ingredient ginsenosides have the potential ability in fighting pathogenic infections. In this study, the P. quinquefolius extract (PQE) showed good antibacterial/bactericidal activity against the M. abscessus planktonic cells. The extract reduced the biomass, thickness, and number of M. abscessus in the biofilm and altered its morphological characteristics as well as the spatial distribution of dead/alive bacteria. Moreover, the ginsenoside CK monomer had a similar inhibitory effect on M. abscessus planktonic bacteria and biofilm formation. Therefore, PQE and its monomer CK might be potential novel antimicrobial agents for the clinical prevention and treatment of M. abscessus, including biofilms in chronic infections.}, } @article {pmid36644335, year = {2023}, author = {Saud, B and Khatri, G and Amatya, N and Paudel, G and Shrestha, V}, title = {Methicillin-Resistant and Biofilm-Producing Staphylococcus aureus in Nasal Carriage among Health Care Workers and Medical Students.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2023}, number = {}, pages = {8424486}, pmid = {36644335}, issn = {1712-9532}, abstract = {Antimicrobial resistance (AMR) is a global threat. It has been portrayed as a slow tsunami. Multidrug resistance and extensive drug resistance exacerbate the already-existing AMR problem. The aim of the study was to access the colonization of methicillin-resistant and biofilm-producing Staphylococcus aureus among healthcare workers (HCWs) and medical students (MSs). A cross-sectional study was designed. A total of 352 participants (176 were HCWs and 176 were MSs) were enrolled from different hospitals and medical colleges in Kathmandu, Nepal. Nasal cavity swab samples were collected and inoculated on Mannitol salt agar at standard in-vitro environmental conditions. Isolates were identified based on colony characteristics, staining properties, and biochemical tests. Identified isolates were tested for antibiotic susceptibility and biofilm production. Out of 352 participants, 65.3% were S. aureus carriers; among the carriers, 52.2% were HCWs and 47.8% were MSs. Of the total isolates, 47.4% isolates were methicillin-resistant S. aureus (MRSA) and 73.9% isolates were multidrug-resistant (MDR). Among MDR isolates, out of 109 MRSA isolates, 86.2% were MDR and out of 121 MSSA isolates, 62.8% were MDR where isolates were mainly resistant to erythromycin. In addition, 68.7% isolates were biofilm-forming; the results were similar in both MRSA and MSSA. Variables such as profession and educational level showed statistical significance (p < 0.05) with MRSA, MSSA, and biofilm producers. In conclusion, asymptomatic colonization of healthcare workers by drug-resistant S. aureus is increasing at alarming rates. This reflects the lack of proper hygiene practice as well as improper disinfection of workplace of study population.}, } @article {pmid36643518, year = {2023}, author = {Akbar, MU and Haque, A and Liaquat, S and Schierack, P and Ali, A}, title = {Biofilm Formation by Staphylococcus epidermidis and Its Inhibition Using Carvacrol, 2-Aminobenzemidazole, and 3-Indole Acetonitrile.}, journal = {ACS omega}, volume = {8}, number = {1}, pages = {682-687}, pmid = {36643518}, issn = {2470-1343}, abstract = {Biofilm-associated bacterial infections are problematic for physicians due to high antimicrobial resistance in biofilm-forming bacteria. Staphylococcus species, particularly Staphylococcus epidermidis, cause severe infections particularly associated with clinical implants. In this study, we have detected the biofilm formation potential of clinical S. epidermidis isolates using phenotypic and genotypic approaches in nutrient-rich and nutrient-deficient growth conditions. The Congo red agar method determined the biofilm formation potential with limited efficacy. However, the tissue culture plate method adroitly classified the isolates as strong, moderate, weak, and non-biofilm producers with five (10%) of the isolates as strong biofilm producers. Ten biofilm-associated genes were targeted, and the fruA gene was found to be the most prevalent (20%). Three antibiofilm compounds, carvacrol, 2-aminobenzemidazole, and 3-indole acetonitrile, were assessed against strong biofilm-producing S. epidermidis isolates. To the best of our knowledge, this is the first report of genotypic and phenotypic detection of biofilms formed by clinical S. epidermidis isolates from this region. The use of 3-indole acetonitrile against these biofilms and toluene as a solvent is novel. The study highlights the significance of biofilm and antibiofilm potential of the studied compounds for effective treatment and control of S. epidermidis infections.}, } @article {pmid36643262, year = {2023}, author = {Kim, HJ and Yoo, HJ}, title = {Inhibitory effects of Streptococcus salivarius K12 on formation of cariogenic biofilm.}, journal = {Journal of dental sciences}, volume = {18}, number = {1}, pages = {65-72}, pmid = {36643262}, issn = {2213-8862}, abstract = {BACGROUND/PURPOSE: Streptococcus salivarius (S. salivarius) K12 is known to be a probiotic bacterium. The purpose of this study was to investigate anti-cariogenic effects of S. salivarius K12 on cariogenic biofilm.

MATERIALS AND METHODS: S. salivarius K12 was cultured in M17 broth. The antimicrobial activity of spent culture medium (SCM) against Streptococcus mutans was investigated. S. salivarius K12 was co-cultivated with S. mutans using a membrane insert. When the biofilm was formed using salivary bacteria and S. mutans, the K12 was inoculated every day. The biomass of biofilm was investigated by a confocal laser scanning microscope. Also, bacterial DNA from the biofilm was extracted, and then bacteria proportion was analyzed by quantitative PCR using specific primers. The expression of gtf genes of S. mutans in the biofilm with or without S. salivarius K12 was analyzed by RT-PCR.

RESULTS: The SCM of S. salivarius K12 inhibited the growth of S. mutans. Also, S. salivarius K12 reduced S. mutans growth in co-cultivation. The formation of cariogenic biofilm was reduced by adding S. salivarius K12, and the count of S. mutans in the biofilm was also decreased in the presence of S. salivarius K12. gtfB, gtfC, and gtfD expression of S. mutans in the biofilm was reduced in the presence of S. salivarius K12.

CONCLUSION: S. salivarius K12 may inhibit the formation of cariogenic biofilm by interrupting the growth and glucosyltransferase production of S. mutans.}, } @article {pmid36642286, year = {2023}, author = {Yang, Y and Li, W and Li, Y and Shi, W and Zhang, J and Dang, W and Zhang, W}, title = {Exogenous c-di-GMP inhibited the biofilm formation of Vibrio splendidus.}, journal = {Microbial pathogenesis}, volume = {175}, number = {}, pages = {105981}, doi = {10.1016/j.micpath.2023.105981}, pmid = {36642286}, issn = {1096-1208}, mesh = {*Proteomics ; *Vibrio cholerae/genetics ; Cyclic GMP/metabolism ; Biofilms ; Bacterial Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Vibrio splendidus, a gram-negative bacterium that is ubiquitously present in marine environments, has been increasingly deemed an important opportunistic pathogen of marine animals. In this study, the biofilm formation of V. splendidus was quantitatively determined and morphologically characterized. Three stages of biofilm formation, including adhesion, aggregation and maturation were observed in the biofilm formed by V. splendidus. The inhibitory effect of exogenous bis (3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) on the biofilm formation from the scratch and preformed established biofilms of V. splendidus was determined. When 200 μmol/L c-di-GMP was added, the quantity of biofilm decreased by 88.1% or 66.7% under the two conditions. To explore the preliminary mechanism of exogenous c-di-GMP on the biofilm formed by V. splendidus, proteomic analysis was performed. GO enrichment analysis showed that exogenous c-di-GMP upregulated biological processes, including the tricarboxylic acid cycle, oxidation‒reduction reactions and organonitrogen compound catabolism and significantly downregulated tRNA threonylcarbamoyladenosine modification, protein dephosphorylation, and lactate transmembrane transporter activity. Sequence-specific DNA binding activity was the most markedly downregulated molecular function. KEGG analysis showed that the valine, leucine and isoleucine degradation pathway was the most enriched pathway, followed by nitrogen metabolism, among the 20 upregulated pathways. Among the downregulated pathways, a nonribosomal peptide structure pathway and the streptomycine, polyketide sugar unit, acarbose and validamycin biosynthesis pathways were significantly enriched. Our present study provides basic data for the biofilm formation of V. splendidus and the preliminary inhibitory mechanism of exogenous c-di-GMP on the biofilm formation of V. splendidus.}, } @article {pmid36642133, year = {2023}, author = {Thakur, K and Kuthiala, T and Singh, G and Arya, SK and Iwai, CB and Ravindran, B and Khoo, KS and Chang, SW and Awasthi, MK}, title = {An alternative approach towards nitrification and bioremediation of wastewater from aquaponics using biofilm-based bioreactors: A review.}, journal = {Chemosphere}, volume = {316}, number = {}, pages = {137849}, doi = {10.1016/j.chemosphere.2023.137849}, pmid = {36642133}, issn = {1879-1298}, mesh = {Animals ; *Nitrification ; *Wastewater ; Ammonia ; Nitrates ; Denitrification ; Biodegradation, Environmental ; Bacteria ; Nitrogen/analysis ; Fishes/microbiology ; Bioreactors/microbiology ; Biofilms ; Water ; }, abstract = {Aquaponics combines the advantages of aquaculture and hydroponics as it suits the urban environment where a lack of agricultural land and water resources is observed. It is an ecologically sound system that completely reuses its system waste as plant fertilizer. It offers sustainable water savings, making it a supreme technology for food production. The two major processes that hold the system together are nitrification and denitrification. The remains of fish in form of ammonia reach the bio filters where it is converted into nitrite and further into nitrate in presence of nitrifying and denitrifying bacteria. Nitrate eventually is taken up by the plants. However, even after the uptake from the flow stream, the effluent contains remaining ammonium and nitrates, which cannot be directly released into the environment. In this review it is suggested how integrating the biofilm-based bioreactors in addition to aquaculture and hydroponics eliminates the possibility of remains of total ammonia nitrogen [TAN] contents, leading to bioremediation of effluent water from the system. Effluent water after releasing from a bioreactor can be reused in an aquaculture system, conditions provided in these bioreactors promote the growth of required bacteria and encourages the mutual development of plants and fishes and eventually leading to bioremediation of wastewater from aquaponics.}, } @article {pmid36641476, year = {2023}, author = {Saeed, SI and Vivian, L and Zalati, CWSCW and Sani, NIM and Aklilu, E and Mohamad, M and Noor, AAM and Muthoosamy, K and Kamaruzzaman, NF}, title = {Antimicrobial activities of graphene oxide against biofilm and intracellular Staphylococcus aureus isolated from bovine mastitis.}, journal = {BMC veterinary research}, volume = {19}, number = {1}, pages = {10}, pmid = {36641476}, issn = {1746-6148}, mesh = {Female ; Animals ; Cattle ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; *Mastitis, Bovine/drug therapy/microbiology ; Microbial Sensitivity Tests/veterinary ; Biofilms ; *Staphylococcal Infections/drug therapy/veterinary/microbiology ; *Cattle Diseases ; }, abstract = {BACKGROUND: S. aureus is one of the causative agents of bovine mastitis. The treatment using conventional antimicrobials has been hampered due to the development of antimicrobial resistance and the ability of the bacteria to form biofilms and localize inside the host cells.

OBJECTIVES: Here, the efficacy of graphene oxide (GO), a carbon-based nanomaterial, was tested against the biofilms and intracellular S. aureus invitro. Following that, the mechanism for the intracellular antimicrobial activities and GO toxicities was elucidated.

METHODS: GO antibiofilm properties were evaluated based on the disruption of biofilm structure, and the intracellular antimicrobial activities were determined by the survival of S. aureus in infected bovine mammary cells following GO exposure. The mechanism for GO intracellular antimicrobial activities was investigated using endocytosis inhibitors. GO toxicity towards the host cells was assessed using a resazurin assay.

RESULTS: At 100 ug/mL, GO reduced between 30 and 70% of S. aureus biofilm mass, suggesting GO's ability to disrupt the biofilm structure. At 200 ug/mL, GO killed almost 80% of intracellular S. aureus, and the antimicrobial activities were inhibited when cells were pre-treated with cytochalasin D, suggesting GO intracellular antimicrobial activities were dependent on the actin-polymerization of the cell membrane. At < 250 ug/mL, GO enhanced the viability of the Mac-T cell, and cells were only affected at higher dosages.

CONCLUSION: The in vitro efficacy of GO against S. aureus in vitro suggested the compound could be further tested in Vivo to zrecognize its potential as one of the components of bovine mastitis therapy.}, } @article {pmid36641190, year = {2023}, author = {Gilmour, KA and Aljannat, M and Markwell, C and James, P and Scott, J and Jiang, Y and Torun, H and Dade-Robertson, M and Zhang, M}, title = {Biofilm inspired fabrication of functional bacterial cellulose through ex-situ and in-situ approaches.}, journal = {Carbohydrate polymers}, volume = {304}, number = {}, pages = {120482}, doi = {10.1016/j.carbpol.2022.120482}, pmid = {36641190}, issn = {1879-1344}, mesh = {*Cellulose/chemistry ; *Bacteria/metabolism ; Tissue Engineering ; Fermentation ; }, abstract = {Bacterial cellulose (BC) has been explored for use in a range of applications including tissue engineering and textiles. BC can be produced from waste streams, but sustainable approaches are needed for functionalisation. To this end, BslA, a B. subtilis biofilm protein was produced recombinantly with and without a cellulose binding module (CBM) and the cell free extract was used to treat BC either ex-situ, through drip coating or in-situ, by incorporating during fermentation. The results showed that ex-situ modified BC increased the hydrophobicity and water contact angle reached 120°. In-situ experiments led to a BC film morphological change and mechanical testing demonstrated that addition of BslA with CBM resulted in a stronger, more elastic material. This study presents a nature inspired approach to functionalise BC using a biofilm hydrophobin, and we demonstrate that recombinant proteins could be effective and sustainable molecules for functionalisation of BC materials.}, } @article {pmid36640857, year = {2023}, author = {Bahrami, R and Pourhajibagher, M and Parker, S and Esmaeili, D and Bahador, A}, title = {Anti-biofilm and bystander effects of antimicrobial photo-sonodynamic therapy against polymicrobial periopathogenic biofilms formed on coated orthodontic mini-screws with zinc oxide nanoparticles.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {41}, number = {}, pages = {103288}, doi = {10.1016/j.pdpdt.2023.103288}, pmid = {36640857}, issn = {1873-1597}, mesh = {Humans ; *Photochemotherapy/methods ; *Zinc Oxide/pharmacology ; Photosensitizing Agents/pharmacology ; Bystander Effect ; *Anti-Infective Agents/pharmacology ; *Nanoparticles ; Cytokines ; Biofilms ; }, abstract = {BACKGROUND: The present study evaluated the anti-biofilm and bystander effects of antimicrobial photo-sonodynamic therapy (aPSDT) on the polymicrobial periopathogenic biofilms formed on mini-screws coated with zinc oxide nanoparticles (ZnONPs).

MATERIALS AND METHODS: Thirty orthodontic identical mini-screws were divided into 6 groups (n = 5) as follows: 1. negative control: uncoated mini-screw + phosphate-buffered saline (PBS), 2. positive control: uncoated mini-screw + 0.2% CHX, 3. coating control: coated mini-screw + PBS, 4. antimicrobial photodynamic therapy (aPDT): coated mini-screw+light emitting diode (LED), 5. Antimicrobial sonodynamic therapy (aSDT): coated mini-screw+ultrasound waves, and 6. aPSDT: coated mini-screw+LED+ultrasound waves. Electrostatic spray-assisted vapor deposition was employed to coat ZnONPs on titanium mini-screws. The biofilm inhibition test was used to assess the anti-biofilm efficacy against polymicrobial periopathogenic biofilms including Porphyromonas gingivitis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans, and the results were shown as the percent reduction of Log10 colony-forming unit (CFU)/mL. Following each treatment, the gene expression levels of TNF-α, IL-1β, and IL-6 were evaluated on human gingival fibroblast (HGF) cells via quantitative real-time polymerase chain reaction (qRT-PCR) to reveal the bystander effects of aPSDT on HGF cells.

RESULTS: A significant reduction in log10 CFU/mL of periopathogens was observed in groups treated with aPDT, aSDT, aPSDT, and 0.2% CHX up to 6.81, 6.63, 5.02, and 4.83 log, respectively, when compared with control groups (P<0.05). 0.2% CHX and aPSDT groups demonstrated significantly higher capacity in eliminating the periopathogen biofilm compared with other groups (P<0.05). The qRT-PCR showed that the expression level of inflammatory cytokines was significantly down regulated in aPDT, aSDT, and aPSDT groups (P<0.05).

CONCLUSION: It was found that the ZnONPs-mediated aPSDT could significantly reduce periopathogen biofilm as well as the expression level of inflammatory cytokines.}, } @article {pmid36640262, year = {2023}, author = {Strateva, T and Trifonova, A and Sirakov, I and Borisova, D and Stancheva, M and Keuleyan, E and Setchanova, L and Peykov, S}, title = {Analysis of biofilm formation in nosocomial Stenotrophomonas maltophilia isolates collected in Bulgaria: An 11-year study (2011-2022).}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {70}, number = {1}, pages = {11-21}, doi = {10.1556/030.2023.01920}, pmid = {36640262}, issn = {1588-2640}, mesh = {Humans ; Bulgaria ; *Stenotrophomonas maltophilia/genetics ; *Cross Infection ; *COVID-19 ; Biofilms ; *Gram-Negative Bacterial Infections ; }, abstract = {The present study aimed to explore the genotypic and phenotypic characteristics of biofilm formation in Bulgarian nosocomial Stenotrophomonas maltophilia isolates (n = 221) during the period 2011-2022, by screening for the presence of biofilm-associated genes (BAG) (spgM, rmlA and rpfF), their mutational variability, and assessment of the adherent growth on a polystyrene surface. The methodology included: PCR amplification, whole-genome sequencing (WGS) and crystal violet microtiter plate assay for biofilm quantification. The overall incidence of BAG was: spgM 98.6%, rmlA 86%, and rpfF 66.5%. The most prevalent genotype was spgM+/rmlA+/rpfF+ (56.1%), followed by spgM+/rmlA+/rpfF- (28.5%), and spgM+/rmlA-/rpfF+ (9.5%), with their significant predominance in lower respiratory tract isolates compared to those with other origin (P < 0.001). All strains examined were characterized as strong biofilm producers (OD550 from 0.224 ± 0.049 to 2.065 ± 0.023) with a single exception that showed a weak biofilm-forming ability (0.177 ± 0.024). No significant differences were observed in the biofilm formation according to the isolation source, as well as among COVID-19 and non-COVID-19 isolates (1.256 ± 0.028 vs. 1.348 ± 0.128, respectively). Also, no correlation was found between the biofilm amounts and the corresponding genotypes. WGS showed that the rmlA accumulated a larger number of variants (0.0086 per base) compared to the other BAG, suggesting no critical role of its product to the biofilm formation. Additionally, two of the isolates were found to harbour class 1 integrons (7-kb and 2.6-kb sized, respectively) containing sul1 in their 3' conservative ends, which confers sulfonamide resistance. To the best of our knowledge, this is the first study on S. maltophilia biofilm formation in Bulgaria, which also identifies novel sequence types (ST819, ST820 and ST826). It demonstrates the complex nature of this adaptive mechanism in the multifactorial pathogenesis of biofilm-associated infections.}, } @article {pmid36639965, year = {2023}, author = {Oliver, C and Céspedes, C and Santibañez, N and Ruiz, P and Romero, A}, title = {Subinhibitory concentrations of florfenicol increase the biofilm formation of Piscirickettsia salmonis.}, journal = {Journal of fish diseases}, volume = {46}, number = {5}, pages = {591-596}, doi = {10.1111/jfd.13757}, pmid = {36639965}, issn = {1365-2761}, support = {//Agencia Nacional de Investigación y Desarrollo (ANID, Chile)/ ; 11180994//Fondo Nacional de Desarrollo Científico y Tecnológico/ ; //Vicerrectoría de Investigación, Desarrollo y Creación Artística (VIDCA)/ ; //Universidad Austral de Chile/ ; }, mesh = {Animals ; *Fish Diseases/microbiology ; *Thiamphenicol/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Piscirickettsia ; Biofilms ; *Piscirickettsiaceae Infections/microbiology ; }, abstract = {Public health is facing a new challenge due to the increased bacterial resistance to most of the conventional antibacterial agents. Inadequate use of antibiotics in the Chilean aquaculture industry leads to the generation of multidrug resistance bacteria. Many fish pathogenic bacteria produce biofilm upon various sources of stress such as antibiotics, which provides several survival advantages for the bacterial life in community and can constitute a reservoir of pathogens in the marine environment. Being florfenicol a broad-spectrum antibiotic commonly used to treat infections in aquaculture, the aim of this study was to assess whether this antibiotic modulates in vitro the biofilm formation in several isolates of Piscirickettsia salmonis. Standard antibiotic-micro broth 96-flat well plates were used to determinate the minimal inhibitory concentration of florfenicol in eight different P. salmonis isolates. In vitro findings, with P. salmonis growing in the presence and absence of the antibiotic, exhibited a statistically significantly increase (p < .05) in biofilm formation in all the bacterial isolates cultivated with sub-MIC (defined as the half of the minimal inhibitory concentration in the presence of antibiotic) of florfenicol compared with controls (antibiotic-free broth). In conclusion, sub-MIC of florfenicol induced an increased biofilm formation in all P. salmonis isolates tested.}, } @article {pmid36639539, year = {2023}, author = {Wang, L and Wang, H and Zhang, H and Wu, H}, title = {Formation of a biofilm matrix network shapes polymicrobial interactions.}, journal = {The ISME journal}, volume = {17}, number = {3}, pages = {467-477}, pmid = {36639539}, issn = {1751-7370}, support = {R01 DE017954/DE/NIDCR NIH HHS/United States ; }, mesh = {*Extracellular Polymeric Substance Matrix ; *Staphylococcus aureus/genetics ; Biofilms ; Staphylococcus ; Fimbriae, Bacterial ; }, abstract = {Staphylococcus aureus colonizes the same ecological niche as many commensals. However, little is known about how such commensals modulate staphylococcal fitness and persistence. Here we report a new mechanism that mediates dynamic interactions between a commensal streptococcus and S. aureus. Commensal Streptococcus parasanguinis significantly increased the staphylococcal biofilm formation in vitro and enhanced its colonization in vivo. A streptococcal biofilm-associated protein BapA1, not fimbriae-associated protein Fap1, is essential for dual-species biofilm formation. On the other side, three staphylococcal virulence determinants responsible for the BapA1-dependent dual-species biofilm formation were identified by screening a staphylococcal transposon mutant library. The corresponding staphylococcal mutants lacked binding to recombinant BapA1 (rBapA1) due to lower amounts of eDNA in their culture supernatants and were defective in biofilm formation with streptococcus. The rBapA1 selectively colocalized with eDNA within the dual-species biofilm and bound to eDNA in vitro, highlighting the contributions of the biofilm matrix formed between streptococcal BapA1 and staphylococcal eDNA to dual-species biofilm formation. These findings have revealed an additional new mechanism through which an interspecies biofilm matrix network mediates polymicrobial interactions.}, } @article {pmid36638844, year = {2023}, author = {Sousa, A and Phung, AN and Škalko-Basnet, N and Obuobi, S}, title = {Smart delivery systems for microbial biofilm therapy: Dissecting design, drug release and toxicological features.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {354}, number = {}, pages = {394-416}, doi = {10.1016/j.jconrel.2023.01.003}, pmid = {36638844}, issn = {1873-4995}, mesh = {Drug Liberation ; *Anti-Bacterial Agents/pharmacology ; Drug Delivery Systems ; *Anti-Infective Agents ; Biofilms ; }, abstract = {Bacterial biofilms are highly protected surface attached communities of bacteria that typically cause chronic infections. To address their recalcitrance to antibiotics and minimise side effects of current therapies, smart drug carriers are being explored as promising platforms for antimicrobials. Herein, we briefly summarize recent efforts and considerations that have been applied in the design of these smart carriers. We guide readers on a journey on how they can leverage the inherent biofilm microenvironment, external stimuli, or combine both types of stimuli in a predictable manner. The specific carrier features that are responsible for their 'on-demand' properties are detailed and their impact on antibiofilm property are further discussed. Moreover, an analysis on the impact of such features on drug release profiles is provided. Since nanotechnology represents a significant slice of the drug delivery pie, some insights on the potential toxicity are also depicted. We hope that this review inspires researchers to use their knowledge and creativity to design responsive systems that can eradicate biofilm infections.}, } @article {pmid36638675, year = {2023}, author = {Feng, K and Lou, Y and Li, Y and Lu, B and Fang, A and Xie, G and Chen, C and Xing, D}, title = {Conductive carrier promotes synchronous biofilm formation and granulation of anammox bacteria.}, journal = {Journal of hazardous materials}, volume = {447}, number = {}, pages = {130754}, doi = {10.1016/j.jhazmat.2023.130754}, pmid = {36638675}, issn = {1873-3336}, mesh = {*Ammonium Compounds/metabolism ; In Situ Hybridization, Fluorescence ; Anaerobic Ammonia Oxidation ; Oxidation-Reduction ; Anaerobiosis ; Sewage/microbiology ; Bacteria/genetics/metabolism ; Biofilms ; Bioreactors/microbiology ; Nitrogen/metabolism ; }, abstract = {The extracellular electron transfer capability of some anaerobic ammonium oxidation (anammox) bacteria was confirmed in recent years. However, the effect of conductive carriers on the synchronous formation of anammox biofilm and granules is rarely reported. Anammox biofilm and granules with compact and stable structures accelerate the initiation and enhance the stability of the anammox process. In this study, we found that the conductive carbon fiber brush (CB) carrier promoted synchronous biofilm formation and granulation of anammox bacteria in the internal circulation immobilized blanket (ICIB) reactor. Compared with polyurethane sponge and zeolite carrier, the ICIB reactor packed with CB carrier can be operated under the highest total nitrogen loading rate of 6.53 kg-N/(m[3]·d) and maintain the effluents NH4[+]-N and NO2[-]-N at less than 1 mM. The volatile suspended solids concentration in the ICIB reactor packed with conductive carrier increased from 5.17 ± 0.40 g/L of inoculum sludge to 24.24 ± 1.20 g/L of biofilm, and the average particle size of granules increased from 222.09 µm to 879.80 µm in 150 days. Fluorescence in situ hybridization analysis showed that anammox bacteria prevailed in the biofilm and granules. The analysis of extracellular polymeric substances indicated that protein and humic acid-like substances played an important role in the formation of anammox biofilm and granules. Microbiome analysis showed that the relative abundance of Candidatus Jettenia was increased from 0.18% to 38.15% in the biofilm from CB carrier during start-up stage. This study provides a strategy for rapid anammox biofilm and granules enrichment and carrier selection of anammox process.}, } @article {pmid36638563, year = {2023}, author = {Cui, W and Hale, RC and Huang, Y and Zhou, F and Wu, Y and Liang, X and Liu, Y and Tan, H and Chen, D}, title = {Sorption of representative organic contaminants on microplastics: Effects of chemical physicochemical properties, particle size, and biofilm presence.}, journal = {Ecotoxicology and environmental safety}, volume = {251}, number = {}, pages = {114533}, doi = {10.1016/j.ecoenv.2023.114533}, pmid = {36638563}, issn = {1090-2414}, mesh = {*Microplastics ; Plastics/chemistry ; Polyethylene/chemistry ; Particle Size ; Adsorption ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microplastic pollution has attracted mounting concerns worldwide. Microplastics may concentrate organic and metallic contaminants; thus, affecting their transport, fate and organismal exposure. To better understand organic contaminant-microplastic interactions, our study explored the sorption of selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), α-hexabromocyclododecane (α-HBCDD), and organophosphate flame retardants (OPFRs) on high-density polyethylene (HDPE) and polyvinylchloride (PVC) microplastics under saline conditions. Sorption isotherms determined varied between chemicals and between HDPE and PVC microplastics. Log Freundlich sorption coefficients (Log KF) for the targeted chemicals ranged from 2.01 to 5.27 L kg[-1] for HDPE, but were significantly lower for PVC, i.e., ranging from Log KF data (2.84 - 8.58 L kg[-1]). Significant correlations between chemicals' Log KF and Log Kow (octanol-water partition coefficient) indicate that chemical-dependent sorption was largely influenced by their hydrophobicity. Sorption was evaluated using three size classes (< 53, 53 - 300, and 300 - 1000 µm) of lab-fragmented microplastics. Particle size did not significantly affect sorption isotherms, but influenced the time to reach equilibrium and the predicted maximum sorption, likely related to microplastic surface areas. The presence of biofilms on HDPE particles significantly enhanced contaminant sorption capacity, indicating more complex sorption dynamics in the chemical-biofilm-microplastic system. Our findings offer new insights into the chemical-microplastic interactions in marine environment.}, } @article {pmid36637413, year = {2023}, author = {Miao, L and Li, C and Adyel, TM and Huang, W and Wu, J and Yu, Y and Hou, J}, title = {Effects of the Desiccation Duration on the Dynamic Responses of Biofilm Metabolic Activities to Rewetting.}, journal = {Environmental science & technology}, volume = {57}, number = {4}, pages = {1828-1836}, doi = {10.1021/acs.est.2c07410}, pmid = {36637413}, issn = {1520-5851}, mesh = {*Ecosystem ; *Desiccation ; Biofilms ; Climate Change ; Rivers ; Carbon ; }, abstract = {Global climate changes have increased the duration and frequency of river flow interruption, affecting the physical and community structure of benthic biofilms. However, the dynamic responses of biofilm metabolism during the dry-wet transition remain poorly understood. Herein, the dynamic changes in biofilm metabolic activities were investigated through mesocosm experiments under short-term (25 day) and long-term drought (90 day), followed by a 20 day rewetting. The biofilm ecosystem metabolism, as measured by gross primary production and community respiration, was significantly inhibited and turned heterotrophic during the desiccation phase and then recovered, becoming autotrophic during the rewetting period regardless of the desiccation periods due to the high resilience of the autotrophic community. However, long-term drought decreased the recovery rate of the ecosystem metabolism and also caused irreparable damage to the biofilm carbon metabolism, measured using Biolog Eco Plates. Specifically, the recovery of the total carbon metabolic activity is related to the specific carbon source utilized by biofilm microorganisms, such as polymers, carbohydrates, and carboxylic acids. However, the divergent changes of amino acids caused the failure of the total carbon metabolism in long-term drought treatments to recover to the control level even after 20 days of rewetting. This research provides direct evidence that the increased duration of non-flow periods affects biofilm-mediated carbon biogeochemical processes.}, } @article {pmid36636842, year = {2023}, author = {Öcalan, F and Mumcuoğlu, İ and Ünaldı, Ö and Bakkaloğlu, Z and Dinç, B}, title = {[Evaluation of Antibiotic Susceptibility, Biofilm Production and Clonal Analysis of Corynebacterium striatum Isolates].}, journal = {Mikrobiyoloji bulteni}, volume = {57}, number = {1}, pages = {1-13}, doi = {10.5578/mb.20239901}, pmid = {36636842}, issn = {0374-9096}, mesh = {Humans ; *Corynebacterium ; Anti-Bacterial Agents/pharmacology ; *Diabetes Mellitus ; Biofilms ; Microbial Sensitivity Tests ; Drug Resistance, Multiple, Bacterial ; }, abstract = {In this study, it was aimed to determine the possible factors affecting the clinical importance of Corynebacterium striatum isolates, which were accepted as infectious or contamination/colonization agents, by comparing their clinical and microbiological characteristics, antimicrobial susceptibility results, biofilm forming abilities and genotypic characteristics. The patients with C.striatum growth in the clinical samples sent to the laboratory were evaluated as infection or contamination/colonization with the evaluation of the examination findings and other laboratory parameters by the relevant physician. This study included 58 isolates, 29 of which were considered as infection and 29 as contamination/colonization. Length of hospital stay, presence of underlying disease [diabetes mellitus (DM), neurological disease, ischemic heart disease, chronic kidney disease, solid tumor], surgical operation status in the last month, and antibiotic use in the last three months of the patients were examined. Identification of the bacterial type was made with MALDI-TOF MS (Bruker/Germany) system. Antimicrobial susceptibility tests were performed by disc diffusion and gradient diffusion method and evaluated according to EUCAST standards. Biofilm production was determined in 96-well microtiter plates on negatively charged polystyrene surfaces. Clonal analyzes were performed by PFGE method using Xba1 enzyme. It was observed that there was no difference in terms of demographic characteristics in the two patient groups included in the study. It was observed that C.striatum strains isolated from outpatients were mostly found in the contamination/ colonization group. The presence of diabetes mellitus, ischemic heart disease, chronic kidney disease and solid tumor was not statistically different in the two patient groups. It was observed that C.striatum strains grown in the samples of patients with neurological disease were mostly found in the infectious agent group (p= 0.025). It has been observed that C.striatum strains grown purely in culture were mostly found in the infectious agent group (p= 0.001). Biofilm production was found to be significantly higher in the infectious agent group (p= 0.015). In antimicrobial susceptibility tests, it was observed that there was widespread multidrug resistance (MDR) in both groups and there was no significant difference between the groups in terms of antimicrobial susceptibility. In our study, it was determined that the strains showed very different PFGE patterns and were not clonally related to each other. In this study, it was determined that the demographic characteristics and comorbidities of the patients were not helpful in evaluating the clinical significance of C.striatum. Biofilm production was observed to be a common virulence factor in C.striatum strains. It was thought that there may be difficulties in the treatment of C.striatum in the future due to the widespread MDR detection among this bacterium strains. Our study contributes to draw attention to the increase in C.striatum infections, resistance and virulence factors.}, } @article {pmid36636617, year = {2023}, author = {Mitra, A and Mukhopadhyay, S}, title = {Regulation of biofilm formation by non-coding RNA in prokaryotes.}, journal = {Current research in pharmacology and drug discovery}, volume = {4}, number = {}, pages = {100151}, pmid = {36636617}, issn = {2590-2571}, abstract = {Biofilm refers to microbes that associate with each other or to a surface via self-synthesized exopolysaccharides and other surface-related structures. The presence of biofilms consisting of pathogenic microbes in the food and clinical environment can pose a threat to human health as microbes in biofilms are highly robust and are difficult to remove. Understanding the process of biofilm formation is crucial for the development of novel strategies to control or harness biofilm. The complex network of proteins, small RNA, and diverse molecules regulate biofilm formation at different steps in biofilm development, including triggering the switch from planktonic to sessile cells, maturation of biofilms, and eventual dispersion of microbes from the biofilms. Small non-coding RNAs are relatively small RNAs that are not translated into proteins and play diverse roles in metabolism, physiology, pathogenesis, and biofilm formation. In this review, we primarily focused on non-coding regulatory RNA that regulates biofilm formation in clinically relevant pathogens or threatens human health. Even though many ncRNA have recently been identified in Archaea, much characterization work remains. The mechanisms and regulatory processes controlled by ncRNA in prokaryotes are covered in this review.}, } @article {pmid36636380, year = {2023}, author = {Mohamad, F and Alzahrani, RR and Alsaadi, A and Alrfaei, BM and Yassin, AEB and Alkhulaifi, MM and Halwani, M}, title = {An Explorative Review on Advanced Approaches to Overcome Bacterial Resistance by Curbing Bacterial Biofilm Formation.}, journal = {Infection and drug resistance}, volume = {16}, number = {}, pages = {19-49}, pmid = {36636380}, issn = {1178-6973}, abstract = {The continuous emergence of multidrug-resistant pathogens evoked the development of innovative approaches targeting virulence factors unique to their pathogenic cascade. These approaches aimed to explore anti-virulence or anti-infective therapies. There are evident concerns regarding the bacterial ability to create a superstructure, the biofilm. Biofilm formation is a crucial virulence factor causing difficult-to-treat, localized, and systemic infections. The microenvironments of bacterial biofilm reduce the efficacy of antibiotics and evade the host's immunity. Producing a biofilm is not limited to a specific group of bacteria; however, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus biofilms are exemplary models. This review discusses biofilm formation as a virulence factor and the link to antimicrobial resistance. In addition, it explores insights into innovative multi-targeted approaches and their physiological mechanisms to combat biofilms, including natural compounds, phages, antimicrobial photodynamic therapy (aPDT), CRISPR-Cas gene editing, and nano-mediated techniques.}, } @article {pmid36635396, year = {2023}, author = {Katsipis, G and Pantazaki, AA}, title = {Serrapeptase impairs biofilm, wall, and phospho-homeostasis of resistant and susceptible Staphylococcus aureus.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {4}, pages = {1373-1389}, pmid = {36635396}, issn = {1432-0614}, mesh = {Humans ; Staphylococcus aureus ; *Methicillin-Resistant Staphylococcus aureus ; Methicillin ; Anti-Bacterial Agents/pharmacology ; Peptide Hydrolases ; *Staphylococcal Infections/microbiology ; Biofilms ; Homeostasis ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus aureus biofilms are implicated in hospital infections due to elevated antibiotic and host immune system resistance. Molecular components of cell wall including amyloid proteins, peptidoglycans (PGs), and lipoteichoic acid (LTA) are crucial for biofilm formation and tolerance of methicillin-resistant S. aureus (MRSA). Significance of alkaline phosphatases (ALPs) for biofilm formation has been recorded. Serrapeptase (SPT), a protease of Serratia marcescens, possesses antimicrobial properties similar or superior to those of many antibiotics. In the present study, SPT anti-biofilm activity was demonstrated against S. aureus (ATCC 25923, methicillin-susceptible strain, methicillin-susceptible S. aureus (MSSA)) and MRSA (ST80), with IC50 values of 0.67 μg/mL and 7.70 μg/mL, respectively. SPT affected bacterial viability, causing a maximum inhibition of - 46% and - 27%, respectively. Decreased PGs content at [SPT] ≥ 0.5 μg/mL and ≥ 8 μg/mL was verified for MSSA and MRSA, respectively. In MSSA, LTA levels decreased significantly (up to - 40%) at lower SPT doses but increased at the highest dose of 2 μg/mL, a counter to spectacularly increased cellular and secreted LTA levels in MRSA. SPT also reduced amyloids of both strains. Additionally, intracellular ALP activity decreased in both MSSA and MRSA (up to - 85% and - 89%, respectively), while extracellular activity increased up to + 482% in MSSA and + 267% in MRSA. Altered levels of DING proteins, which are involved in phosphate metabolism, in SPT-treated bacteria, were also demonstrated here, implying impaired phosphorus homeostasis. The differential alterations in the studied molecular aspects underline the differences between MSSA and MRSA and offer new insights in the treatment of resistant bacterial biofilms. KEY POINTS: • SPT inhibits biofilm formation in methicillin-resistant and methicillin-susceptible S. aureus. • SPT treatment decreases bacterial viability, ALP activity, and cell wall composition. • SPT-treated bacteria present altered levels of phosphate-related DING proteins.}, } @article {pmid36635042, year = {2023}, author = {Andrade, KM and Silva, BPM and de Oliveira, LR and Cury, PR}, title = {Automatic dental biofilm detection based on deep learning.}, journal = {Journal of clinical periodontology}, volume = {50}, number = {5}, pages = {571-581}, doi = {10.1111/jcpe.13774}, pmid = {36635042}, issn = {1600-051X}, mesh = {Humans ; *Deep Learning ; *Tooth ; Neural Networks, Computer ; Biofilms ; }, abstract = {AIM: To estimate the automated biofilm detection capacity of the U-Net neural network on tooth images.

MATERIALS AND METHODS: Two datasets of intra-oral photographs taken in the frontal and lateral views of permanent and deciduous dentitions were employed. The first dataset consisted of 96 photographs taken before and after applying a disclosing agent and was used to validate the domain's expert biofilm annotation (intra-class correlation coefficient = .93). The second dataset comprised 480 photos, with or without orthodontic appliances, and without disclosing agents, and was used to train the neural network to segment the biofilm. Dental biofilm labelled by the dentist (without disclosing agents) was considered the ground truth. Segmentation performance was measured using accuracy, F1 score, sensitivity, and specificity.

RESULTS: The U-Net model achieved an accuracy of 91.8%, F1 score of 60.6%, specificity of 94.4%, and sensitivity of 67.2%. The accuracy was higher in the presence of orthodontic appliances (92.6%).

CONCLUSIONS: Visually segmenting dental biofilm employing a U-Net is feasible and can assist professionals and patients in identifying dental biofilm, thus improving oral hygiene and health.}, } @article {pmid36632686, year = {2023}, author = {Taha, M and Arulanandam, R and Chen, A and Diallo, JS and Abdelbary, H}, title = {Combining povidone-iodine with vancomycin can be beneficial in reducing early biofilm formation of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus on titanium surface.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {111}, number = {5}, pages = {1133-1141}, doi = {10.1002/jbm.b.35220}, pmid = {36632686}, issn = {1552-4981}, mesh = {Animals ; Rats ; *Methicillin-Resistant Staphylococcus aureus ; Vancomycin/pharmacology ; Povidone-Iodine/pharmacology ; Staphylococcus aureus ; Methicillin ; Titanium/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {There is controversial clinical evidence regarding the added antibacterial benefit of locally administering antiseptic solutions or antibiotics to the infected joint space. The objectives of this in vitro study were to test the efficacy of povidone-iodine (PVP-I) and vancomycin in treating premature and developed Staphylococcus aureus biofilms grown on titanium implant surfaces. PVP-I and vancomycin were used to treat immature and developed biofilms formed by two clinical strains of S. aureus (BP043-MRSA, PB011-MSSA). S. aureus strains were grown as immature (3 h-old) or developed (24 h-old) biofilm. These biofilms were grown on titanium plasma sprayed discs. The treatment regimens tested were: 0.8% PVP-I, 500 μg/ml vancomycin as well as a combination of vancomycin and PVP-I. PVP-I was tested at 3 min, as per current clinical practice, versus 1 min treatment times. In addition, the cytotoxicity of the PVP-I and vancomycin was tested using fresh skeletal muscle tissue cores harvested from the rat's abdominal muscles using alamarBlue assay. The combination of PVP-I (3 min) and vancomycin (24 h.) showed synergistic interaction and the best efficacy against immature biofilms formed by both clinical strains. This degree of eradication was statistically significant compared to the untreated control, p < .0001. However, this combination therapy had limited efficiency against developed biofilms. Also, PVP-I alone was more effective when exposure time was 3 min instead of 1 min against immature biofilm for MRSA, p = .02, and MSSA, p = .01. PVP-I and vancomycin were not effective against developed biofilm regardless of exposure time. Also, combining PVP-I and vancomycin was not cytotoxic to muscle tissue. Combining PVP-I with vancomycin is superior in reducing viable S. aureus cells in immature biofilms grown on titanium surface without causing significant cytotoxicity to muscle tissue. Exposure times and biofilm maturity play a role in dictating the efficacy of using local antiseptics and antibiotics to treat biofilms on implant surfaces.}, } @article {pmid36631126, year = {2023}, author = {Shiiki, H and Goto, S and Katsuragi, H and Kobayashi, S}, title = {The bactericidal and biofilm removal effect of super reducing water on Streptococcus mutans in three types of orthodontic brackets.}, journal = {Journal of oral science}, volume = {65}, number = {1}, pages = {48-52}, doi = {10.2334/josnusd.22-0320}, pmid = {36631126}, issn = {1880-4926}, mesh = {*Streptococcus mutans ; Water ; *Orthodontic Brackets/microbiology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {PURPOSE: To investigate the bactericidal and biofilm removal effect of super reducing water (SRW) on Streptococcus mutans (S. mutans) adhered to orthodontic brackets, in vitro.

METHODS: Three types of brackets were bonded to aluminum disks. After the formation of S. mutans biofilms on the surfaces, the brackets were divided into three groups (n = 44 each) based on their exposure to SRW: group 1, no treatment; group 2, treated for 5 min; and group 3, treated for 10 min. Total viable counts, adenosine triphosphate measurements, crystal violet assay, and scanning electron microscopy were used to evaluate the effect of SRW.

RESULTS: The bacterial counts in groups 2 and 3 were significantly lower than those in group 1 (P < 0.001); however, no significant differences were observed between groups 2 and 3. Marked decreases in the number of bacterial colonies and extent of biofilm formation were observed in groups 2 and 3 compared to group 1. No significant differences in the number of bacterial colonies and amount of biofilm were observed among the three types of brackets in each group.

CONCLUSION: These findings indicate the bactericidal and biofilm removal effect of SRW treatment on S. mutans adhered to orthodontic brackets.}, } @article {pmid36630113, year = {2023}, author = {Murphy, CA and Bowler, PG and Chowdhury, MF}, title = {'Granulitis': defining a common, biofilm-induced, hyperinflammatory wound pathology.}, journal = {Journal of wound care}, volume = {32}, number = {1}, pages = {22-28}, doi = {10.12968/jowc.2023.32.1.22}, pmid = {36630113}, issn = {0969-0700}, mesh = {Humans ; *Clinical Decision-Making ; *Wound Infection/drug therapy ; Uncertainty ; Wound Healing ; Biofilms ; }, abstract = {The hard-to-heal (chronic) wound condition, now believed to be inextricably linked to the presence of microbial biofilm, has posed challenges in translating scientific understanding to clinical practice in recent decades. During this time, multiple descriptive terms of the wound pathology have been described, including critical colonisation, biofilm infection and inflammatory stasis. However, the absence of naming this disease state as a specifically identified condition that is tangible to treat has led to some confusion and delay in possible therapeutic approaches. When there is clinical uncertainty of wound status, antibiotics are too often inappropriately administered as a precaution. We therefore propose that introducing the term 'granulitis' (inflamed, unhealthy granulation tissue) could be used to identify the biofilm-induced, persistent inflammatory wound condition. This will help to raise clinician and public awareness of the condition, guide appropriate and prompt local wound hygiene, and encourage allocation of adequate resources to improve wound healing outcomes globally.}, } @article {pmid36629151, year = {2023}, author = {Raile, PN and Oliveira, VC and Macedo, AP and Curylofo, PA and Marcato, PD and Watanabe, E and Paranhos, HFO and Pagnano, VO}, title = {Action of chitosan-based solutions against a model four-species biofilm formed on cobalt-chromium and acrylic resin surfaces.}, journal = {Gerodontology}, volume = {}, number = {}, pages = {}, doi = {10.1111/ger.12672}, pmid = {36629151}, issn = {1741-2358}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {OBJECTIVE: To evaluate the anti-biofilm action of chitosan, nanoparticulate chitosan, and denture cleanser Nitradine™ against biofilms comprising Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans.

BACKGROUND: Biofilm removal from removable partial dentures (RPD) is important for success in prosthetic rehabilitation.

MATERIALS AND METHODS: The anti-biofilm action of the experimental chitosan-based solutions and Nitradine™ was evaluated on acrylic resin and cobalt-chromium alloy through assessing cell viability, cell metabolism, residual aggregated biofilm, and extracellular polymeric substance and biofilm morphology.

RESULTS: Only chitosan reduced the viability of C. albicans on cobalt-chromium alloy surface, by 98% (a 1.7 log10 reduction in cfu). Chitosan-based solutions neither promoted substantial alteration of the metabolic activity of the four-species biofilm nor reduced the amount of the aggregated biofilm. After immersion in chitosan and nanoparticulate chitosan, viable microorganisms and extracellular polymeric substances distributed over the entire specimens' surfaces were observed. Nitradine™ reduced the viability and metabolic activity of biofilm grown on both surfaces, but it did not remove all aggregated biofilm and extracellular polymeric substances. After immersion in Nitradine™, approximately 35% of the specimens' surfaces remained covered by aggregated biofilm, mainly composed of dead cells.

CONCLUSION: Although chitosan and Nitradine™ promoted changes in the viability of microorganisms, neither solution completely removed the four-species biofilm from the Co-Cr and acrylic resin surfaces. Thus, isolated use of hygiene solutions is not indicated for biofilm control on RPDs; this requires complementary mechanical removal.}, } @article {pmid36626577, year = {2023}, author = {Jia, T and Wu, P and Liu, B and Liu, M and Mu, H and Liu, D and Huang, M and Li, L and Wei, Y and Wang, L and Yang, Q and Liu, Y and Yang, B and Huang, D and Yang, L and Liu, B}, title = {The phosphate-induced small RNA EsrL promotes E. coli virulence, biofilm formation, and intestinal colonization.}, journal = {Science signaling}, volume = {16}, number = {767}, pages = {eabm0488}, doi = {10.1126/scisignal.abm0488}, pmid = {36626577}, issn = {1937-9145}, mesh = {Animals ; Humans ; Rabbits ; *Escherichia coli/genetics/metabolism ; Virulence/genetics ; *Escherichia coli Proteins/genetics/metabolism ; Phosphates/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; }, abstract = {Escherichia coli are part of the normal intestinal microbiome, but some enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC) strains can cause potentially life-threatening gastroenteritis. Virulence factors underlying the ability of EHEC and EPEC to cause disease include those encoded in the locus of the enterocyte effacement (LEE) pathogenicity island. Here, we demonstrated that EsrL, a small RNA present in many E. coli strains, promoted pathogenicity, adhesion, and biofilm formation in EHEC and EPEC. PhoB, the response regulator of the two-component system that controls cellular responses to phosphate, directly repressed esrL expression under low-phosphate conditions. A phosphate-rich environment, similar to that of the human intestine, relieved PhoB-mediated repression of esrL. EsrL interacted with and stabilized the LEE-encoded regulator (ler) transcript, which encodes a transcription factor for LEE genes, leading to increased bacterial adhesion to cultured cells and colonization of the rabbit colon. EsrL also bound to and stabilized the fimC transcript, which encodes a chaperone that is required for the assembly of type 1 pili, resulting in enhanced cell adhesion in pathogenic E. coli and enhanced biofilm formation in pathogenic and nonpathogenic E. coli. Our findings demonstrate that EsrL stimulates the expression of virulence genes in both EHEC and EPEC under phosphate-rich conditions, thus promoting the pathogenicity of EHEC and EPEC in the nutrient-rich gut environment.}, } @article {pmid36626427, year = {2022}, author = {Huang, Y and Qin, F and Li, S and Yin, J and Hu, L and Zheng, S and He, L and Xia, H and Liu, J and Hu, W}, title = {The mechanisms of biofilm antibiotic resistance in chronic rhinosinusitis: A review.}, journal = {Medicine}, volume = {101}, number = {49}, pages = {e32168}, pmid = {36626427}, issn = {1536-5964}, mesh = {Humans ; *Methicillin-Resistant Staphylococcus aureus ; *Rhinitis/microbiology ; Biofilms ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Drug Resistance, Microbial ; *Sinusitis/microbiology ; Chronic Disease ; }, abstract = {Chronic rhinosinusitis (CRS) is a common but burdensome ailment that is still poorly understood in terms of its pathogenesis. The existence of biofilms on the sinonasal mucosa of individuals with CRS has been proven by current biofilm identification methods. Current treatments for CRS generally include functional endoscopic sinus surgery, biofilm-removing strategies, and limited therapies that target quorum sensing (QS), patients with CRS are often resistant to antimicrobial therapy at degrees achievable by oral or intravenous administration, and even a subset of patients fail to react to either medical or surgical intervention. Multidrug-resistant Pseudomonas aeruginosa, Staphylococcus aureus, especially methicillin-resistant S. aureus, Streptococcus pneumoniae, and Haemophilus influenzae are the most commonly implicated bacteria in CRS patients, which may lead to the persistence and severity of CRS and antibiotic treatment failure via the formation of biofilms. Resistance to antibiotics is attributed to the 3-dimensional structure and QS of biofilms, and the latter describes the communication of bacteria within biofilms. A better understanding of biofilms in CRS and their contribution to the antibiotic resistance of CRS is critical for novel treatment strategies. This review mainly discusses the special structure of biofilms, QS, and their mechanisms of antibiotic resistance in order to investigate prospective anti-biofilm therapies, suggest future directions for study, and potentially refine the CRS prevention paradigm.}, } @article {pmid36622758, year = {2023}, author = {Pan, Y and Zou, J and Zhang, K and Wang, X and Ma, Q and Mei, L and Li, Y and Pan, Y}, title = {ZccE, a P-type ATPase contributing to biofilm formation and competitiveness in Streptococcus mutans.}, journal = {Molecular oral microbiology}, volume = {38}, number = {3}, pages = {198-211}, doi = {10.1111/omi.12405}, pmid = {36622758}, issn = {2041-1014}, mesh = {Humans ; Streptococcus mutans/metabolism ; Adenosine Triphosphatases/genetics/metabolism/pharmacology ; *Dental Caries/microbiology ; Biofilms ; Acids/pharmacology ; Zinc/pharmacology/metabolism ; *P-type ATPases/metabolism ; }, abstract = {Most living organisms require zinc for survival; however, excessive amounts of this trace element can be toxic. Therefore, the frequent fluctuations of salivary zinc, caused by the low physiological level and the frequent introduction of exogenous zinc ions, present a serious challenge for bacteria colonizing the oral cavity. Streptococcus mutans is considered one of the main bacterial pathobiont in dental caries. Here, we verified the role of a P-type ATPase ZccE as the main zinc-exporting transporter in S. mutans and delineated the effects of zinc toxification caused by zccE deletion in the physiology of this bacterium. The deletion of the gene zccE severely impaired the ability of S. mutans to grow under high zinc stress conditions. Intracellular metal quantification using inductively coupled plasma optical emission spectrometer revealed that the zccE mutant exhibited approximately two times higher zinc accumulation than the wild type when grown in the presence of a subinhibitory zinc concentration. Biofilm formation analysis revealed less single-strain biofilm formation and competitive weakness in the dual-species biofilm formed with Streptococcus sanguinis for zccE mutant under high zinc stress. The quantitive reverse transcription polymerase chain reaction test revealed decreased expressions of gtfB, gtfC, and nlmC in the mutant strain under excessive zinc treatment. Collectively, these findings suggest that ZccE plays an important role in the zinc detoxification of S. mutans and that zinc is a growth-limiting factor for S. mutans within the dental biofilm.}, } @article {pmid36622717, year = {2023}, author = {Moore, RE and Spicer, SK and Talbert, JA and Manning, SD and Townsend, SD and Gaddy, JA}, title = {Anti-biofilm Activity of Human Milk Oligosaccharides in Clinical Strains of Streptococcus agalactiae with Diverse Capsular and Sequence Types.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {24}, number = {6}, pages = {e202200643}, pmid = {36622717}, issn = {1439-7633}, support = {I01 BX005352/BX/BLRD VA/United States ; R01 HD090061/HD/NICHD NIH HHS/United States ; UL1 RR024975-01/RR/NCRR NIH HHS/United States ; UL1 TR000445-06/TR/NCATS NIH HHS/United States ; }, mesh = {Pregnancy ; Female ; Humans ; *Milk, Human ; *Streptococcus agalactiae ; Anti-Bacterial Agents/pharmacology ; Oligosaccharides/pharmacology ; Biofilms ; }, abstract = {Group B Streptococcus (GBS) is an encapsulated Gram-positive bacterial pathogen that causes severe perinatal infections. Human milk oligosaccharides (HMOs) are short-chain sugars that have recently been shown to possess antimicrobial and anti-biofilm activity against a variety of bacterial pathogens, including GBS. We have expanded these studies to demonstrate that HMOs can inhibit and dismantle biofilm in both invasive and colonizing strains of GBS. A cohort of 30 diverse strains of GBS were analyzed for susceptibility to HMO-dependent biofilm inhibition or destruction. HMOs were significantly effective at inhibiting biofilm in capsular-type- and sequence-type-specific fashion, with significant efficacy in CpsIb, CpsII, CpsIII, CpsV, and CpsVI strains as well as ST-1, ST-12, ST-19, and ST-23 strains. Interestingly, CpsIa as well as ST-7 and ST-17 were not susceptible to the anti-biofilm activity of HMOs, underscoring the strain-specific effects of these important antimicrobial molecules against the perinatal pathogen Streptococcus agalactiae.}, } @article {pmid36622472, year = {2023}, author = {Marzhoseyni, Z and Rashki, S and Nazari-Alam, A}, title = {Evaluation of the inhibitory effects of TiO2 nanoparticle and Ganoderma lucidum extract against biofilm-producing bacteria isolated from clinical samples.}, journal = {Archives of microbiology}, volume = {205}, number = {2}, pages = {59}, doi = {10.1007/s00203-023-03403-4}, pmid = {36622472}, issn = {1432-072X}, mesh = {*Methicillin-Resistant Staphylococcus aureus ; *Reishi ; Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; *Nanoparticles/chemistry ; Bacteria ; Microbial Sensitivity Tests ; }, abstract = {The emergence of multidrug-resistant pathogens leads to treatment failure. So, the need for new antibacterial drugs is urgent. We evaluated the antibacterial and antibiofilm effects of titanium dioxide (TiO2) nanoparticles (NPs) and Ganoderma extract against biofilm-producing Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) by microbroth dilution and crystal violet assays. The combined effect of these compounds was studied using the checkerboard method. The OD260 was measured to assess the destruction of the membrane permeability. The expression of biofilm-related genes (iacA and algD) was investigated by real-time PCR. MRSA isolate was more susceptible to test compounds. The OD260 increased and algD gene was down-regulated after treatment with TiO2 NPs and a combination of TiO2 NPs and Ganoderma extract. iacA gene did not affect by test compounds. Overall, these findings revealed that nanoparticles and natural substances might represent the potential candidates to develop promising antibacterial agents, especially against Gram-positive bacteria.}, } @article {pmid36622157, year = {2023}, author = {Yang, J and Yun, S and Park, W}, title = {Blue Light Sensing BlsA-Mediated Modulation of Meropenem Resistance and Biofilm Formation in Acinetobacter baumannii.}, journal = {mSystems}, volume = {8}, number = {1}, pages = {e0089722}, pmid = {36622157}, issn = {2379-5077}, mesh = {*Acinetobacter baumannii/genetics ; Meropenem/pharmacology ; Light ; Biofilms ; }, abstract = {The presence or absence of BlsA, a protein with a blue light-sensing flavin domain in the genomes of Acinetobacter species has aroused curiosity about its roles in the regulation of bacterial lifestyle under light. Genomic and transcriptomic analyses revealed the loss of BlsA in several multidrug-resistant (MDR) A. baumannii strains as well as the light-mediated induction of blsA, along with a possible BlsA-interacting partner BipA. Their direct in vivo interactions were verified using a bacterial two-hybrid system. The results demonstrated that the C-terminal region of BipA could bind to the C-terminal residues of BlsA under blue light at 23°C but not at 37°C. Genetic manipulations of blsA and bipA revealed that the coexistence of BlsA and BipA was required to induce the light-dependent expression of ompA in A. baumannii ATCC 17978 at 23°C. The same phenomenon occurred in the BlsA-deficient MDR strain in our functional complementation assay; however, the underlying molecular mechanism remains poorly understood. BlsA-modulated amounts of OmpA, the most abundant porin, in the outer membrane affected the membrane integrity and permeability of small molecules. Dark conditions or the deletion of ompA made the membrane more permeable to lipophilic ethidium bromide (EtBr) but not to meropenem. Interestingly, light illumination and low temperature conditions made the cells more sensitive to meropenem; however, this bactericidal effect was not noted in the blsA mutant or in the BlsA-deficient MDR strains. Light-mediated cell death and the reduction of biofilm formation at 23°C were abolished in the blsA mutant strain, suggesting multifaceted roles of BlsA in A. baumannii strains. IMPORTANCE Little is known about the functional roles of BlsA and its interacting partners in Acinetobacter species. Intriguingly, no BlsA homolog was found in several clinical isolates, suggesting that BlsA was not required inside the host because of the lack of blue light and the warm temperature conditions. As many chromophore-harboring proteins interact with various partners to control light-dependent cellular behaviors, the maintenance of blsA in the genomes of many Acinetobacter species during their evolution may be beneficial when fluctuations occur in two important environmental factors: light and temperature. Our study is the first to report the novel protein partner of BlsA, namely, BipA, and its contribution to multiple phenotypic changes, including meropenem resistance and biofilm formation. Rapid physiological acclimation to changing light or temperature conditions may be possible in the presence of the light-sensing BlsA protein, which may have more interacting partners than expected.}, } @article {pmid36621329, year = {2023}, author = {Shamkani, F and Barzi, SM and Badmasti, F and Chiani, M and Mirabzadeh, E and Zafari, M and Shafiei, M}, title = {Enhanced anti-biofilm activity of the minocycline-and-gallium-nitrate using niosome wrapping against Acinetobacter baumannii in C57/BL6 mouse pneumonia model.}, journal = {International immunopharmacology}, volume = {115}, number = {}, pages = {109551}, doi = {10.1016/j.intimp.2022.109551}, pmid = {36621329}, issn = {1878-1705}, mesh = {Mice ; Animals ; Minocycline/therapeutic use ; *Acinetobacter baumannii ; Liposomes/therapeutic use ; Nitrates ; Iran ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Gallium/therapeutic use ; *Pneumonia/drug therapy/microbiology ; Microbial Sensitivity Tests ; }, abstract = {Acinetobacter baumannii is a worldwide health issue in terms of its high antibiotic resistance and ability to form biofilms. Nanoparticles (NPs) with high biocompatibility, high penetrating ability, and low medication dose can successfully treat the antibiotic-resistant infections. In this research, the anti-biofilm activity of niosomes containing minocycline and gallium nitrate (GaN) against A. baumannii biofilm was determined. In order to improve their anti-biofilm properties, minocycline and GaN were encapsulated in niosomes as biocompatible drug carriers. The niosomes' size, zeta potential, shape, stability, drug entrapment efficacy, drug release pattern and antibacterial activity were assessed. Several clinical samples were isolated from the lungs of patients hospitalized at Loghman hospital, Tehran, Iran. The biofilm formation of most lethal clinical isolates of A. baumannii was analyzed. The pneumonia model was generated by intranasally administering A. baumannii suspension to anesthetized mice whose immune systems was compromised twice by cyclophosphamide. Lung infection of the mouse with A. baumannii was confirmed using PCR. After treatment, the lungs were excised under sterile conditions and stained with hematoxylin and eosin (H&E) to determine histological symptoms, inflammation and intercellular secretions. The niosomes contained minocycline and GaN had an average size of 230 nm and a zeta potential of -40 mV, respectively. The percentage of drug entrapment and delayed drug release was both high in niosomal formulations. Niosomes containing minocycline and GaN dispersed 1, 3 and 5 day old biofilms. The mice given the combination of two compounds required less time to be treated than the animals given the single medication (minocycline). The minocycline& GaN-loaded niosomes could be considered as promising candidates to treat the infections caused by A. baumannii biofilm.}, } @article {pmid36619994, year = {2022}, author = {Ma, X and Wang, X and Ye, S and Liu, J and Yuan, H and Wang, N}, title = {Biofilm and pathogenic factor analysis of Gardnerella vaginalis associated with bacterial vaginosis in Northeast China.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1033040}, pmid = {36619994}, issn = {1664-302X}, abstract = {INTRODUCTION: Gardnerella vaginalis is a major pathogen responsible for bacterial vaginosis (BV). However, the recurrence of infection and the antibiotic resistance of biofilms remain significant challenges for the treatment of BV. In this study, we aimed to analyze the pathogenic factors and drug sensitivity associated with the clinical treatment of BV in Northeast China.

METHODS: Subgroups were identified by clade-specific polymerase chain reaction (PCR). Biofilm formation was measured by crystal violet staining, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The inhibition and eradication of biofilm formation were measured by XTT and broth recovery-based methods.

RESULTS: Of the 24 samples of G. vaginalis, 11 samples and American Type Culture Collection (ATCC) 14018 formed biofilms; the remainder did not. The positive rates of detection for the sialidase A and vly genes in the 24 G. vaginalis samples were 100% and 79.2%, respectively. Moreover, 21 samples (87.5%) showed resistance to metronidazole and 16 (66.7%) presented with sensitivity towards clindamycin. The biofilm MIC80 (BMIC80) of metronidazole for ATCC14018 was 16 μg/ml while that of clindamycin was 0.125 μg/ml. The minimum biofilm eradication concentration (MBEC) of metronidazole was > 256 μg/ml while that of clindamycin was > 2 μg/ml.

DISCUSSION: Our results revealed that G. vaginalis is more resistant to metronidazole than clindamycin and neither metronidazole nor clindamycin are able to effectively eradicate vaginal biofilms. Thus, the role of antibiotics and biofilms in BV requires further investigation.}, } @article {pmid36619751, year = {2022}, author = {Morais, MLGDS and Santos, MGC and Costa, CL and Martins, CS and Leitão, RFC and de Melo Pacífico, D and Quesada-Gómez, C and Castelo Branco, D and Ferreira, EO and Brito, GAC}, title = {Comparative biofilm-forming ability between Clostridioides difficile strains isolated in Latin America and the epidemic NAP1/027 strain.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1033698}, pmid = {36619751}, issn = {2235-2988}, mesh = {Humans ; Bacterial Proteins/genetics/metabolism ; *Bacterial Toxins/metabolism ; Biofilms ; *Clostridioides difficile/genetics/metabolism ; *Clostridium Infections/microbiology ; Latin America ; Multilocus Sequence Typing ; Vancomycin/pharmacology ; }, abstract = {INTRODUCTION: One of the challenges in treating Clostridioides difficile infection (CDI) is that the bacterium forms biofilms, a critical virulence mechanism known to promote antibiotic resistance and, as a result, consequently, a higher recurrence of the disease. The goal of this study was to compare the ability of three MLST Clade 2 strains to form a biofilm in vitro: ICC-45 (ribotype SLO231/UK[CE]821), a ST41 toxinotype IXb isolated in Brazil; and two epidemic NAP1/027/ST01 strains: NAP1/027/ST01 (LIBA5756), isolated during a 2010 outbreak in Costa Rica and the reference epidemic strain NAP1/027/ST01 (R20291); and ATCC700057, a non-toxigenic strain.

METHODS: The ability of strains to form biofilm was evaluated using crystal violet staining. In addition, samples were stained with the Film Tracer biofilm matrix (Invitrogen®) and the biofilm matrix thickness was measured using confocal microscopy. The matrix architecture was determined using Scanning electron microscop. Confocal microscopy was used to detect the presence of toxin A (tcdA) using an anti-Clostridioides difficile TcdA antibody. The expression of virulence genes (tcdA, tcdB, tcdC, cdtB, spo0A, slpA, cwp66 and cwp84) was examined, as well as the effect of antibiotics metronidazole (MTZ) and vancomycin (VAN) on biofilm growth.

RESULTS: All of the strains tested formed a moderate biofilm with 1.1 3.5. After 72h, biofilm biomass of the NAP1/027/ST01 epidemic strains (LIBA5756 and R20291) was significantly higher than ICC-45 and ATCC 700057 biofilms, as confirmed by electron and confocal microscopy. At 120h, the LIBA5756 biofilm biomass decreased compared to other strains. The toxigenic strains R20291 or LIBA 5756 had higher expression of genes tcdA, tcdB, tcdC, cdtA, slpA and spo0A than ICC-45, but there were no significant differences in the expression levels of cdtB, cwp66 and cwp84. In epidemic strains, VAN and MTZ inhibited biofilm formation; however, in the ICC-45 strain, MIC concentrations of VAN and MIC and 4MIC of MTZ did not inhibit biofilm formation.

CONCLUSION: The three MLST Clade 2 isolated from different rybotipes, two of which were isolated from Latin America, are competent biofilm-forming bacteria, indicating their ability to induce C. difficile infection recurrence, making treatment difficult.}, } @article {pmid36619453, year = {2022}, author = {Rashtchi, P and Tempelaars, M and van der Linden, E and Abee, T and Habibi, M}, title = {Lactobacillus plantarum strains show diversity in biofilm formation under flow conditions.}, journal = {Heliyon}, volume = {8}, number = {12}, pages = {e12602}, pmid = {36619453}, issn = {2405-8440}, abstract = {In many natural and technological applications, microbial biofilms grow under fluid flow. In this project, we investigated the influence of flow on the formation and growth of biofilms produced by gram-positive Lactobacillus plantarum strains WCFS1 and CIP104448. We used an in-house designed device based on a 48-well plate with culture volumes of 0.8 ml, and quantified total biofilm formation under static and flow conditions with flow rates 0.8, 1.6, 3.2 and 4.8 ml/h (with 1, 2, 4 and 6 volume changes per hour) using crystal violet (CV) staining, and determined the number of viable biofilm cells based on plate counts. The amount of total biofilm under flow conditions increased in the CIP 104448 strain, with significantly increased staining at the wall of the wells. However, in the WCFS1 strain, no significant difference in the amount of biofilm formed under flow and static conditions was observed. Plate counts showed that flow caused an increase in the number of viable biofilm cells for both strains. In addition, using enzyme treatment experiments, we found that for WCFS1 in the static condition, the amount of mature biofilm was declined after DNase I and Proteinase K treatment, while for flow conditions, the decline was only observed for DNase I treatment. The CIP104448 biofilms formed under both static and flow conditions only showed a decline in the CV staining after adding Proteinase K, indicating different contributions of extracellular DNA (eDNA) and proteinaceous matrix components to biofilm formation in the tested strains.}, } @article {pmid36618067, year = {2023}, author = {Zhang, Y and Yu, H and Xie, Y and Guo, Y and Cheng, Y and Yao, W}, title = {Inhibitory effects of hexanal on acylated homoserine lactones (AHLs) production to disrupt biofilm formation and enzymes activity in Erwinia carotovora and Pseudomonas fluorescens.}, journal = {Journal of food science and technology}, volume = {60}, number = {1}, pages = {372-381}, pmid = {36618067}, issn = {0022-1155}, abstract = {UNLABELLED: Erwinia carotovora and Pseudomonas fluorescens were two bacteria commonly caused the spoilage of vegetables through biofilm formation and secretion of extracellular enzymes. In this study, N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL) and N-Octanoyl-L-homoserine lactone (C8-HSL) were confirmed as acylated homoserine lactones (AHLs) signal molecule produced by E. carotovora and P. fluorescens, respectively. In addition, quorum sensing inhibitory (QSI) effects of hexanal on AHLs production were evaluated. Hexanal at 1/2 minimum inhibitory concentration (MIC) was achieved 76.27% inhibitory rate of 3-oxo-C6-HSL production in E. carotovora and a inhibitory rate of C8-HSL (60.78%) in P. fluorescens. The amount of biofilm formation and activity of extracellular enzymes treated with 1/2 MIC of hexanal were restored with different concentrations (10 ng/mL, 50 ng/mL, 100 ng/mL) of exogenous AHLs (P < 0.05), which verified QSI effect of hexanal on biofilm and extracellular enzymes were due to its inhibition on AHLs production. Molecular docking analysis showed that hexanal could interact with EcbI and PcoI protein to disrupt AHLs production. Furthermore, results showed that sub-MICs of hexanal could suppress expressions of ecbI and pcoI genes in AHL-mediated QS system of E. carotovora and P. fluorescens. This study provides theoretical support for the application of essential oils as QS inhibitors in the preservation of vegetables.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-022-05624-9.}, } @article {pmid36616511, year = {2022}, author = {Choi, S and Lee, H and Hong, R and Jo, B and Jo, S}, title = {Application of Multi-Layered Temperature-Responsive Polymer Brushes Coating on Titanium Surface to Inhibit Biofilm Associated Infection in Orthopedic Surgery.}, journal = {Polymers}, volume = {15}, number = {1}, pages = {}, pmid = {36616511}, issn = {2073-4360}, abstract = {Infection associated with biomedical implants remains the main cause of failure, leading to reoperation after orthopedic surgery. Orthopedic infections are characterized by microbial biofilm formation on the implant surface, which makes it challenging to diagnose and treat. One potential method to prevent and treat such complications is to deliver a sufficient dose of antibiotics at the onset of infection. This strategy can be realized by coating the implant with thermoregulatory polymers and triggering the release of antibiotics during the acute phase of infection. We developed a multi-layered temperature-responsive polymer brush (MLTRPB) coating that can release antibiotics once the temperature reaches a lower critical solution temperature (LCST). The coating system was developed using copolymers composed of diethylene glycol methyl ether methacrylate and 2-hydroxyethyl methacrylate by alternatively fabricating monomers layer by layer on the titanium surface. LCST was set to the temperature of 38-40 °C, a local temperature that can be reached during infection. The antibiotic elution characteristics were investigated, and the antimicrobial efficacy was tested against S. aureus species (Xen29 ATCC 29 213) using one to four layers of MLTRPB. Both in vitro and in vivo assessments demonstrated preventive effects when more than four layers of the coating were applied, ensuring promising antibacterial effects of the MLTRPB coating.}, } @article {pmid36614237, year = {2023}, author = {Maliszewska, I and Zdubek, A}, title = {On the Photo-Eradication of Methicillin-Resistant Staphylococcus aureus Biofilm Using Methylene Blue.}, journal = {International journal of molecular sciences}, volume = {24}, number = {1}, pages = {}, pmid = {36614237}, issn = {1422-0067}, mesh = {*Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; *Photochemotherapy/methods ; Methylene Blue/pharmacology ; Gold/pharmacology ; *Metal Nanoparticles ; Biofilms ; Anti-Bacterial Agents ; }, abstract = {This work compared the effectiveness of several Methylene Blue (MB)-based protocols for photo-eradication of biofilms formed on the surface of the glass and stainless steel discs by S. aureus MRSA isolates using a diode laser (λ = 665 nm; output power 40 mW; energy fluence was 189 J cm[-2]). The results obtained showed that MB alone, up to a concentration of 62.5 mgL[-1], had limited photo-bactericidal activity. It was possible to enhance the activity of MB using two types of spherical gold nanoparticles of similar sizes, 15 ± 3 nm/20 ± 3 nm, but differing in the method of their synthesis and stabilization. The enhancement of the photodestruction effect was related to the increased production of hydroxyl radicals by the MB+gold nanoparticles mixture, and this mixture showed dark cytotoxicity against the cocci studied. Effective destruction (mortality above 99.9%) of the biofilms formed by MRSA isolates was also possible without the use of gold nanoparticles, but the concentration of MB had to be at least 125 mgL[-1]. A highly efficient protocol of photodestruction of biofilms, consisting of triple exposure of biofilms to laser light in the presence of MB alone, combined with the removal of dead bacteria protecting deep layers of pathogens against photosensitization, was also described.}, } @article {pmid36614040, year = {2022}, author = {Jean-Pierre, V and Boudet, A and Sorlin, P and Menetrey, Q and Chiron, R and Lavigne, JP and Marchandin, H}, title = {Biofilm Formation by Staphylococcus aureus in the Specific Context of Cystic Fibrosis.}, journal = {International journal of molecular sciences}, volume = {24}, number = {1}, pages = {}, pmid = {36614040}, issn = {1422-0067}, support = {NîmAO 2018.02//Centre Hospitalier Universitaire de Nîmes/ ; }, mesh = {Child ; Humans ; *Cystic Fibrosis/complications ; Staphylococcus aureus/physiology ; *Staphylococcal Infections ; Biofilms ; Phenotype ; Anti-Bacterial Agents ; }, abstract = {Staphylococcus aureus is a major human pathogen whose characteristics support its success in various clinical settings including Cystic Fibrosis (CF). In CF, S. aureus is indeed the most commonly identified opportunistic pathogen in children and the overall population. S. aureus colonization/infection, either by methicillin-susceptible or methicillin-resistant strains, will become chronic in about one third of CF patients. The persistence of S. aureus in CF patients' lungs, despite various eradication strategies, is favored by several traits in both host and pathogen. Among the latter, living in biofilm is a highly protective way to survive despite deleterious environmental conditions, and is a common characteristic shared by the main pathogens identified in CF. This is why CF has earned the status of a biofilm-associated disease for several years now. Biofilm formation by S. aureus, and the molecular mechanisms governing and regulating it, have been extensively studied but have received less attention in the specific context of CF lungs. Here, we review the current knowledge on S. aureus biofilm in this very context, i.e., the importance, study methods, molecular data published on mono- and multi-species biofilm and anti-biofilm strategies. This focus on studies including clinical isolates from CF patients shows that they are still under-represented in the literature compared with studies based on reference strains, and underlines the need for such studies. Indeed, CF clinical strains display specific characteristics that may not be extrapolated from results obtained on laboratory strains.}, } @article {pmid36613809, year = {2022}, author = {Chudzik-Rząd, B and Zalewski, D and Kasela, M and Sawicki, R and Szymańska, J and Bogucka-Kocka, A and Malm, A}, title = {The Landscape of Gene Expression during Hyperfilamentous Biofilm Development in Oral Candida albicans Isolated from a Lung Cancer Patient.}, journal = {International journal of molecular sciences}, volume = {24}, number = {1}, pages = {}, pmid = {36613809}, issn = {1422-0067}, mesh = {Humans ; Antifungal Agents ; *Biofilms ; *Candida albicans/genetics ; Gene Expression ; Iron ; *Lung Neoplasms/microbiology ; }, abstract = {The filamentation ability of Candida albicans represents one of the main virulence factors allowing for host tissue penetration and biofilm formation. The aim of this paper was to study the genetic background of the hyperfilamentous biofilm development in vitro in C. albicans isolated from the oral cavity of a lung cancer patient. Analyzed C. albicans isolates (CA1, CA2, CA3) were chosen based on their different structures of mature biofilm. The CA3 isolate possessing hyperfilamentation properties and forming high biofilm was compared with CA1 and CA2 isolates exhibiting low or average biofilm-forming ability, respectively. The detailed biofilm organization was studied with the use of confocal scanning laser microscopy. The whole transcriptome analysis was conducted during three stages of biofilm development (24 h, 48 h, 72 h). In contrast to CA1 and/or CA2 isolate, the CA3 isolate was characterized by a significant upregulation of genes encoding for cell wall proteins (HWP1, PGA13, PGA44, ALS3) and candidalysin (ECE1), as well as being involved in iron metabolism (FRE1, ALS3), sulfur metabolism (HAL21), the degradation of aromatic compounds (HQD2), and membrane transport (DIP5, PHO89, TNA1). In contrast, some genes (SCW11, FGR41, RBE1) in the CA3 were downregulated. We also observed the overexpression of a few genes over time-mainly FRE1, ATX1, CSA2 involved in iron metabolism. This is the first insight into the potential function of multiple genes in the hyperfilamentous biofilm formation in C. albicans, primarily isolated from host tissue, which may have an important clinical impact on cancer patients. Moreover, the presented data can lay the foundation for further research on novel pathogen-specific targets for antifungal drugs.}, } @article {pmid36613306, year = {2022}, author = {Savijoki, K and San-Martin-Galindo, P and Pitkänen, K and Edelmann, M and Sillanpää, A and van der Velde, C and Miettinen, I and Patel, JZ and Yli-Kauhaluoma, J and Parikka, M and Fallarero, A and Varmanen, P}, title = {Food-Grade Bacteria Combat Pathogens by Blocking AHL-Mediated Quorum Sensing and Biofilm Formation.}, journal = {Foods (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {36613306}, issn = {2304-8158}, support = {325784//Academy of Finland/ ; NNF20OC0065096//Novo Nordisk Foundation/ ; 322012//Academy of Finland/ ; 348973//Academy of Finland/ ; 2017-19//Jane and Aatos Erkko Foundation/ ; }, abstract = {Disrupting bacterial quorum sensing (QS) signaling is a promising strategy to combat pathogenic biofilms without the development of antibiotic resistance. Here, we report that food-associated bacteria can interfere with the biofilm formation of a Gram-negative pathogenic bacterium by targeting its AHL (acyl-homoserine lactone) QS system. This was demonstrated by screening metabolic end-products of different lactobacilli and propionibacteria using Gram-negative and biofilm-forming Chromobacterium violaceum as the QS reporter and our anti-QS microscale screening platform with necessary modifications. The method was optimized in terms of the inoculation technique and the concentrations of D-glucose and L-tryptophan, two key factors controlling the synthesis of violacein, a purple pigment indicating the activation of the QS system in C. violaceum. These improvements resulted in ca. 16-times higher violacein yields and enabled revealing anti-QS effects of Lactobacillus acidophilus, Lentilactobacillus kefiri, Lacticaseibacillus rhamnosus and Propionibacterium freudenreichii, including new cheese-associated strains. Our findings also suggest that acetate and propionate excreted by these species are the main factors that interrupt the QS-mediated signaling and subsequent biofilm growth without affecting the cell viability of the C. violaceum reporter. Thus, the present study reports a revised anti-QS screening method to accurately define new bacteria with an ability to combat pathogens in a safe and sustainable way.}, } @article {pmid36610197, year = {2023}, author = {Zhu, W and Chen, J and Zhang, H and Yuan, S and Guo, W and Zhang, Q and Zhang, S}, title = {Start-up phase optimization of pyrite-intensified hybrid sequencing batch biofilm reactor (PIHSBBR): Mixotrophic denitrification performance and mechanism.}, journal = {Journal of environmental management}, volume = {330}, number = {}, pages = {117232}, doi = {10.1016/j.jenvman.2023.117232}, pmid = {36610197}, issn = {1095-8630}, mesh = {*Denitrification ; Nitrates ; Bioreactors ; Nitrification ; Biofilms ; Nitrogen ; *Ammonium Compounds ; Oxidation-Reduction ; Sewage ; }, abstract = {Pyrite-based autotrophic denitrification (PAD) is an emerging biological process to diminish nitrate pollution, but the relatively low NO3[-]-N removal rate limits its practical application. In this research, a pyrite-intensified hybrid sequencing batch biofilm reactor (PIHSBBR) was designed to treat low C/N ratio domestic wastewater. The results showed that PIHSBBR could achieve optimal removal of COD, NH4[+]-N, and TN under the aeration rate of 1.0 L/L∙min and the hydraulic retention time (HRT) of 8 h, with removal rates of 69.67 ± 4.37%, 77.04 ± 4.84%, and 63.92 ± 6.66%, respectively. The PAD efficiency in PIHSBBR during the stable operation was not high (13.05-31.01%), and the main nitrogen removal pathway in PIHSBBR, especially in the aerobic zone, was simultaneous nitrification and denitrification (SND). High-throughput sequencing analysis unraveled that Planctomycetota (3.65%) had a high abundance in the anoxic zone of PIHSBBR, implying that anaerobic ammonium oxidation (anammox) might have occurred in the anoxic zone. In addition, the nitrogen cycle function gene with the highest abundance was nirBD, indicating the possible presence of dissimilatory nitrate reduction to ammonium (DNRA) within the system (aerobic and anoxic zones). Our research can provide useful information for the improvement and future application of PIHSBBR.}, } @article {pmid36608761, year = {2023}, author = {Wang, WQ and Feng, XC and Shi, HT and Wang, YM and Jiang, CY and Xiao, ZJ and Xu, YJ and Zhang, X and Yuan, Y and Ren, NQ}, title = {Biofilm inhibition based on controlling the transmembrane transport and extracellular accumulation of quorum sensing signals.}, journal = {Environmental research}, volume = {221}, number = {}, pages = {115218}, doi = {10.1016/j.envres.2023.115218}, pmid = {36608761}, issn = {1096-0953}, mesh = {*Quorum Sensing ; Eugenol/pharmacology ; Biofilms ; *Saponins/pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins ; }, abstract = {The regulation of bacterial quorum sensing (QS) has been used to inhibit biofouling in wastewater treatment plants and the formation of biofilms. In contrast to traditional QS regulation strategies, this study aimed to obstruct the transmembrane transport process of QS signals to decrease their extracellular accumulation. Three phytochemicals, astragaloside IV, eugenol, and baicalin were selected, their effects on biofilm formation by Pseudomonas aeruginosa PA14 were studied, and the mechanisms determined. The inhibition efficiency of biofilm formation by 50 mg/L astragaloside IV, 1 mg/L eugenol, and 1 mg/L baicalin were 37%, 26%, and 26%, respectively. Confocal laser scanning microscopy and analysis of extracellular polymeric substances indicated that the three inhibitors affected the structure and composition of the biofilms. Furthermore, bacterial motility and a variety of QS-related virulence factors were suppressed by the inhibitor treatment due to changes in bacterial QS. Notably, the three inhibitors all decreased the extracellular concentration of the QS signaling molecule 3-oxo-C12-homoseine lactone by affecting the function of efflux pump MexAB-OprM. This indirectly interfered with the bacterial QS system and thus inhibited biofilm formation. In conclusion, this study revealed the inhibitory effects and inhibition mechanism of three phytochemicals on efflux pump and QS of P. aeruginosa and realized the inhibition on biofilm formation. We update the efflux pump inhibitor library and provide a new way for biofilm contamination control.}, } @article {pmid36608472, year = {2023}, author = {Su, Z and Kong, L and Mei, J and Li, Q and Qian, Z and Ma, Y and Chen, Y and Ju, S and Wang, J and Jia, W and Zhu, C and Fan, W}, title = {Enzymatic bionanocatalysts for combating peri-implant biofilm infections by specific heat-amplified chemodynamic therapy and innate immunomodulation.}, journal = {Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy}, volume = {67}, number = {}, pages = {100917}, doi = {10.1016/j.drup.2022.100917}, pmid = {36608472}, issn = {1532-2084}, mesh = {Animals ; *Hot Temperature ; Escherichia coli ; Hydrogen Peroxide/pharmacology ; Biofilms ; Cell Line, Tumor ; *Neoplasms ; Tumor Microenvironment ; }, abstract = {Bacterial biofilm-associated infection is a life-threatening emergency contributing from drug resistance and immune escape. Herein, a novel non-antibiotic strategy based on the synergy of bionanocatalysts-driven heat-amplified chemodynamic therapy (CDT) and innate immunomodulation is proposed for specific biofilm elimination by the smart design of a biofilm microenvironment (BME)-responsive double-layered metal-organic framework (MOF) bionanocatalysts (MACG) composed of MIL-100 and CuBTC. Once reaching the acidic BME, the acidity-triggered degradation of CuBTC allows the sequential release of glucose oxidase (GOx) and an activable photothermal agent, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). GOx converts glucose into H2O2 and gluconic acid, which can further acidify the BME to accelerate the CuBTC degradation and GOx/ABTS release. The in vitro and in vivo results show that horseradish peroxidase (HRP)-mimicking MIL-100 in the presence of self-supplied H2O2 can catalyze the oxidation of ABTS into oxABTS to yield a photothermal effect that breaks the biofilm structure via eDNA damage. Simultaneously, the Cu ion released from the degraded CuBTC can deplete glutathione and catalyze the splitting of H2O2 into •OH, which can effectively penetrate the heat-induced loose biofilms and kill sessile bacteria (up to 98.64%), such as E. coli and MRSA. Particularly, MACG-stimulated M1-macrophage polarization suppresses the biofilm regeneration by secreting pro-inflammatory cytokines (e.g., IL-6, TNF-α, etc.) and forming a continuous pro-inflammatory microenvironment in peri-implant biofilm infection animals for at least 14 days. Such BME-responsive strategy has the promise to precisely eliminate refractory peri-implant biofilm infections with extremely few adverse effects.}, } @article {pmid36606321, year = {2022}, author = {Soontarach, R and Nwabor, OF and Voravuthikunchai, SP}, title = {Interaction of lytic phage T1245 with antibiotics for enhancement of antibacterial and anti-biofilm efficacy against multidrug-resistant Acinetobacter baumannii.}, journal = {Biofouling}, volume = {38}, number = {10}, pages = {994-1005}, doi = {10.1080/08927014.2022.2163479}, pmid = {36606321}, issn = {1029-2454}, mesh = {*Anti-Bacterial Agents/pharmacology ; Meropenem/pharmacology ; *Acinetobacter baumannii ; Ceftazidime/pharmacology ; Colistin/pharmacology ; Drug Synergism ; Drug Resistance, Multiple, Bacterial ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Biofilms associated with multidrug-resistant (MDR) Acinetobacter baumannii on medical devices remain a big clinical problem. Antibiotic susceptibility tests were performed with eight commonly employed antibiotics against clinical isolates. The effects of antibiotics in combination with well-characterized lytic phage T1245 were studied to assess their antibacterial and anti-biofilm efficacy. Ceftazidime, colistin, imipenem, and meropenem significantly reduced bacterial density up to approximately 80% when combined with phage T1245, compared with control. Phage T1245 in combination with ceftazidime, colistin, and meropenem at subinhibitory concentrations demonstrated significant reduction in biomass and bacterial viability of 3-day established biofilms, compared with antibiotic alone. In addition, electron microscopy further confirmed the disruption of biofilm structure and cell morphology upon treatment with phage T1245 and antibiotics, including ceftazidime, colistin, and meropenem. Combined treatment of phage T1245 with these antibiotics could be employed for the management of A. baumannii infections and eradication of the bacterial biofilms.}, } @article {pmid36606087, year = {2023}, author = {Yum, SJ and Jeong, HG and Kim, SM}, title = {Anti-biofilm effects of sinomenine against Staphylococcus aureus.}, journal = {Food science and biotechnology}, volume = {32}, number = {1}, pages = {83-90}, pmid = {36606087}, issn = {2092-6456}, abstract = {Staphylococcus aureus is a gram-positive foodborne pathogen capable of forming strong biofilms. This study identified that anti-biofilm natural compound against S. aureus. Sinomenine, a natural compound, showed significantly reduced biofilm formation (31.97-39.86%), but no effect on bacterial growth was observed. The dispersion of preformed biofilms was observed by confocal laser scanning microscopy (CLSM). qRT-PCR revealed that sinomenine treatment significantly up-regulated agrA by 3.8-fold and down-regulated icaA gene by 3.1-fold. These indicate that sinomenine treatment induces biofilm dispersal due to cell-cell adhesion, polysaccharide intercellular adhesin (PIA), and phenol-soluble modulin (PSM) peptides production. Our results suggest that sinomenine can be used as a promising agent for effectively controlling biofilm formation and dispersion, thereby making S. aureus more susceptible to the action of antimicrobial agents.}, } @article {pmid36606039, year = {2023}, author = {Gou, H and Cao, Q and Wang, Z and Liu, Y and Sun, Y and Wei, H and Song, C and Tian, C and Wei, Y and Xue, H}, title = {Transcriptomic analysis of Listeria monocytogenes biofilm formation at different times.}, journal = {Canadian journal of veterinary research = Revue canadienne de recherche veterinaire}, volume = {87}, number = {1}, pages = {59-66}, pmid = {36606039}, issn = {1928-9022}, mesh = {Animals ; *Listeria monocytogenes/genetics ; Transcriptome ; Biofilms ; }, abstract = {Biofilm (BF) formation is a considerable obstacle to the effective control of Listeria monocytogenes (LM). In this study, we used transcriptomics to analyze LM BF and planktonic bacteria at different stages of BF formation and growth to compare differential gene expression between the 2. We identified 1588, 1517, and 1462 differentially expressed genes (DEGs) when early formation BF and planktonic bacteria were compared at 12, 24, and 48 h, respectively. Among these, 1123 DEGs were shared across the 3 data pool. Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses demonstrated significant changes associated with the phosphotransferase system, the microbial metabolism in diverse environments, the flagella assembly, the bacterial chemotaxis, the bacterial secretion, the quorum sensing, and the 2-component system. The top 5 upregulated DEGs were lmo0024, lmo0374, lmo0544, hly, and lmo2434. The top 5 downregulated DEGs were lmo2192, lmo1211, cheY, lmo0689, and secY. After real-time quantitative polymerase chain reaction, the expression of these 10 DEGs were consistent with the results of the transcriptomic sequence. This research lays the foundation for further studies on mechanisms regulating BF formation and will help to identify BF inhibitors to reduce the risk of LM infection.}, } @article {pmid36605406, year = {2023}, author = {Gu, M and Cho, JH and Suh, JW and Cheng, J}, title = {Potential oral probiotic Lactobacillus pentosus MJM60383 inhibits Streptococcus mutans biofilm formation by inhibiting sucrose decomposition.}, journal = {Journal of oral microbiology}, volume = {15}, number = {1}, pages = {2161179}, pmid = {36605406}, issn = {2000-2297}, abstract = {Streptococcus mutans is known as a contributor to dental caries. In this work, Lactobacillus pentosus MJM60383 was selected for its strong antagonistic activity against S. mutans and was characterized by good oral probiotic properties including lysozyme tolerance, adhesive ability to oral cells, good aggregation (auto-aggregation, co-aggregation) ability, hydrogen peroxide production and inhibition of biofilm formation of S. mutans. L. pentosus MJM60383 also exhibited safety as a probiotic characterized by no hemolytic activity, no D-lactate production, no biogenic amine production, and susceptibility to antibiotics. Furthermore, the biofilm formation of S. mutans was also significantly inhibited by the supernatant of L. pentosus MJM60383. An anti-biofilm mechanism study revealed that sucrose decomposition and the production of water-insoluble exopolysaccharides by S. mutans were inhibited by the treatment with L. pentosus MJM60383 supernatant. Real-time PCR analysis indicated that the supernatant of L. pentosus MJM60383 significantly inhibited the mRNA expression of S. mutans glycosyltransferases, which synthesize glucan to construct biofilm architecture and mediate bacterial adherence. Our study demonstrated L. pentosus MJM60383 as a potential oral probiotic and revealed its anti-biofilm mechanism.}, } @article {pmid36605101, year = {2022}, author = {Jalalifar, S and Mirzaei, R and Motallebirad, T and Razavi, S and Talebi, M}, title = {The Emerging Role of Probiotics and their Derivatives against Biofilm-Producing MRSA: A Scoping Review.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {4959487}, pmid = {36605101}, issn = {2314-6141}, mesh = {Humans ; *Methicillin-Resistant Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Staphylococcal Infections/drug therapy/prevention & control/microbiology ; *Probiotics/therapeutic use ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main bacterial pathogens causing chronic infections, mainly because of its capacity to produce biofilm. Biofilm production is one of the underlying strategies for antibacterial drug resistance. Accordingly, preventing and attenuating biofilm production has become an emerging approach to controlling persistent infections. Therefore, this scoping review is aimed at surveying the published literature describing the usage of probiotics and their derivatives against biofilm-producing MRSA.

METHODS: Updated literature searches were conducted across seven electronic databases including Web of Science, PubMed, Scopus, Cochrane Library, ProQuest, Embase, and Google Scholar to identify all original published articles about probiotics against MRSA. In this regard, studies were summarized and analyzed in the present review.

RESULTS: In the reviewed studies, various microorganisms and compounds were used as probiotics as follows: Lactobacillus species (8 studies), Enterococcus species (4 studies), Bacillus species (2 studies), Streptomyces species (2 studies), Saccharomyces cerevisiae (1 study), Corynebacterium accolens (1 study), and Lactococcus lactis derived Nisin (3 studies). Based on our comprehensive search, 21 studies with eligibility criteria were included in the present review including 12 studies on clinical strains, 6 studies on ATCC, 2 studies simultaneously on clinical and standard strains, and finally 1 study on food sample.

CONCLUSIONS: Our study showed that there was an increasing trend in the number of publications reporting probiotics against biofilm-producing MRSA. The results of this scoping review could use to guide the undertaking of the subsequent systematic reviews. In summary, probiotics with antimicrobial and antibiofilm properties can use as an embedded agent in food products or as a biopharmaceutical in the prevention and treatment of MRSA infections.}, } @article {pmid36603516, year = {2023}, author = {Ren, S and Yang, Y and Xia, M and Deng, Y and Zuo, Y and Lei, L and Hu, T}, title = {A Chinese herb preparation, honokiol, inhibits Streptococcus mutans biofilm formation.}, journal = {Archives of oral biology}, volume = {147}, number = {}, pages = {105610}, doi = {10.1016/j.archoralbio.2022.105610}, pmid = {36603516}, issn = {1879-1506}, mesh = {Humans ; Streptococcus mutans ; *Lignans/pharmacology ; *Dental Caries/prevention & control/microbiology ; Biofilms ; Lactic Acid ; }, abstract = {OBJECTIVE: This study aimed to investigate the antibiofilm and anticariogenic effects of honokiol, a traditional Chinese medicine, on the cariogenic bacterium Streptococcus mutans (S. mutans).

DESIGN: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of honokiol on S. mutans UA159 were measured. Then, S. mutans were treated with honokiol at concentrations of 1/2 MIC and 1/4 MIC. Extracellular polysaccharide (EPS) synthesis was assessed with confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric method. Crystal violet staining and scanning electron microscopy (SEM) were used to demonstrate the characteristics and morphology of S. mutans biofilms. Colony-forming unit (CFU) assay was performed to observe the antibacterial effect of honokiol. Lactic acid production of 24-h biofilms was measured by the lactic acid assay. The expression level of caries-related genes (gtfB/C/D, comD/E and ldh) was identified by quantitative real-time PCR (qRTPCR) to explore the relevant mechanism. And the cytotoxic effect on human gingival fibroblasts (HGFs) was evaluated by the Cell Counting Kit-8 (CCK-8) assay.

RESULTS: The MIC and MBC of honokiol on S. mutans were 30 μg/mL and 60 μg/mL, respectively. Honokiol inhibited biofilm formation, EPS synthesis and lactic acid production. It also decreased the expression of glucosyltransferases (Gtfs) and quorum sensing (QS) system encoding genes. Moreover, honokiol showed favorable biocompatibility with HGFs.

CONCLUSIONS: Honokiol has an inhibitory effect on S. mutans and favorable biocompatibility, with application potential as a novel anticaries agent.}, } @article {pmid36603307, year = {2023}, author = {He, H and Zhang, C and Yang, X and Huang, B and Zhe, J and Lai, C and Liao, Z and Pan, X}, title = {The efficient treatment of mature landfill leachate using tower bipolar electrode flocculation-oxidation combined with electrochemical biofilm reactors.}, journal = {Water research}, volume = {230}, number = {}, pages = {119544}, doi = {10.1016/j.watres.2022.119544}, pmid = {36603307}, issn = {1879-2448}, mesh = {*Waste Disposal, Fluid/methods ; *Water Pollutants, Chemical/chemistry ; Flocculation ; Oxidation-Reduction ; Electrodes ; }, abstract = {Mature landfill leachate contains high concentrations of organic and inorganic compounds that inhibit the performance of conventional biological treatment. Nowadays, few single treatment techniques could fulfill the requirements of cleaning mature landfill leachate. In this study, a tower bipolar electrode flocculation-oxidation (BEF-O) reactor and an electrochemical biofilm reactor (EBR) combine device was constructed to effectively treat mature landfill leachate. And the removal efficiency and mechanism of various pollutants using the BEF-O reactor were investigated. The BEF-O system with the current density of 100 mA/cm[2] shows excellent treatment efficiency, which can roundly remove most pollutants (NH4[+]-N, COD and heavy metals, etc.), and increase the bioavailability of the effluent to facilitate subsequent EBR treatment. Benefiting from the metabolic stimulation and population selection effect of electric current on microorganisms, EBR has a denser biofilm, stronger anti-pollution load capacity, superior, and stable pollution treatment efficiency. More importantly, the combined device can reduce the concentrations of COD and NH4[+]-N from 6410 to 338 mg/L and 4065 to 4 mg/L, respectively, and has an economical energy consumption of 32.02 kWh/(kg COD) and 54.04 kWh/ (kg NH4[+]-N). To summarize, this research could provide an innovative and industrial application prospect technology for the mature landfill leachate treatment.}, } @article {pmid36602323, year = {2023}, author = {Regmi, A and Tague, JG and Boas Lichty, KE and Boyd, EF}, title = {A Class IV Adenylate Cyclase, CyaB, Is Required for Capsule Polysaccharide Production and Biofilm Formation in Vibrio parahaemolyticus.}, journal = {Applied and environmental microbiology}, volume = {89}, number = {1}, pages = {e0187422}, pmid = {36602323}, issn = {1098-5336}, mesh = {*Adenylyl Cyclases/genetics/metabolism ; *Vibrio parahaemolyticus/genetics/metabolism ; Escherichia coli/genetics/metabolism ; Phylogeny ; Cyclic AMP/metabolism ; Bacterial Proteins/genetics/metabolism ; Cyclic AMP Receptor Protein/genetics/metabolism ; Biofilms ; Polysaccharides ; }, abstract = {Cyclic AMP (cAMP) receptor protein (CRP), encoded by crp, is a global regulator that is activated by cAMP, a second messenger synthesized by a class I adenylate cyclase (AC-I) encoded by cyaA in Escherichia coli. cAMP-CRP is required for growth on nonpreferred carbon sources and is a global regulator. We constructed in-frame nonpolar deletions of the crp and cyaA homologs in Vibrio parahaemolyticus and found that the Δcrp mutant did not grow in minimal media supplemented with nonpreferred carbon sources, but the ΔcyaA mutant grew similarly to the wild type. Bioinformatics analysis of the V. parahaemolyticus genome identified a 181-amino-acid protein annotated as a class IV adenylate cyclase (AC-IV) named CyaB, a member of the CYTH protein superfamily. AC-IV phylogeny showed that CyaB was present in Gammaproteobacteria and Alphaproteobacteria as well as Planctomycetes and Archaea. Only the bacterial CyaB proteins contained an N-terminal motif, HFxxxxExExK, indicative of adenylyl cyclase activity. Both V. parahaemolyticus cyaA and cyaB genes functionally complemented an E. coli ΔcyaA mutant. The Δcrp and ΔcyaB ΔcyaA mutants showed defects in growth on nonpreferred carbon sources and in swimming and swarming motility, indicating that cAMP-CRP is an activator. The ΔcyaA and ΔcyaB single mutants had no defects in these phenotypes, indicating that AC-IV complements AC-I. Capsule polysaccharide and biofilm production assays showed significant defects in the Δcrp, ΔcyaBΔcyaA, and ΔcyaB mutants, whereas the ΔcyaA strain behaved similarly to the wild type. This is consistent with a role of cAMP-CRP as an activator of these phenotypes and establishes a cellular role for AC-IV in capsule and biofilm formation, which to date has been unestablished. IMPORTANCE Here, we characterized the roles of CRP and CyaA in V. parahaemolyticus, showing that cAMP-CRP is an activator of metabolism, motility, capsule production, and biofilm formation. These results are in contrast to cAMP-CRP in V. cholerae, which represses capsule and biofilm formation. Previously, only an AC-I CyaA had been identified in Vibrio species. Our data showed that an AC-IV CyaB homolog is present in V. parahaemolyticus and is required for optimal growth. The data demonstrated that CyaB is essential for capsule production and biofilm formation, uncovering a physiological role of AC-IV in bacteria. The data showed that the cyaB gene was widespread among Vibrionaceae species and several other Gammaproteobacteria, but in general, its phylogenetic distribution was limited. Our phylogenetic analysis also demonstrated that in some species the cyaB gene was acquired by horizontal gene transfer.}, } @article {pmid36602005, year = {2023}, author = {Zhu, W and Tang, JY and Yu, D and Shen, AG}, title = {Silent Raman imaging of highly effective anti-bacterial activity synchronous with biofilm breakage using poly(4-cyanostyrene)@silver@polylysine nanocomposites.}, journal = {The Analyst}, volume = {148}, number = {3}, pages = {628-635}, doi = {10.1039/d2an01831d}, pmid = {36602005}, issn = {1364-5528}, mesh = {Escherichia coli ; Silver/pharmacology ; Polylysine/pharmacology ; *Metal Nanoparticles ; Staphylococcus aureus ; Anti-Bacterial Agents/pharmacology ; *Nanocomposites ; Biofilms ; }, abstract = {Biofilms are known to be a great challenge for their anti-bacterial activity as they obstruct drug action for deeper and more thorough bacteria-killing effects. Therefore, developing highly effective antibacterial agents to destroy biofilms and eradicate bacteria is of great significance. Herein, a new type of nanocomposites (denoted as poly(4-cyanostyrene)@silver@polylysine) is proposed, in which polylysine (PLL) could rapidly capture the biofilms and exhibit excellent antibacterial efficacy together with decorated silver (Ag) nanoparticles (NPs) through the charge effect and Ag[+] release. Notably, nearly 100% antibacterial rates against Gram-positive bacterium (Staphylococcus aureus, S. aureus) and Gram-negative bacterium (Escherichia coli, E. coli) were achieved. More importantly, poly(4-cyanostyrene) with biological silent Raman imaging capacity is able to illustrate the relationship between antibacterial efficiency and biofilm breakage. In short, such novel nanocomposites can improve the bioavailability of each component and display tremendous potential in antibacterial applications.}, } @article {pmid36601891, year = {2023}, author = {Straub, H and Zuber, F and Eberl, L and Maniura-Weber, K and Ren, Q}, title = {In Situ Investigation of Pseudomonas aeruginosa Biofilm Development: Interplay between Flow, Growth Medium, and Mechanical Properties of Substrate.}, journal = {ACS applied materials & interfaces}, volume = {15}, number = {2}, pages = {2781-2791}, doi = {10.1021/acsami.2c20693}, pmid = {36601891}, issn = {1944-8252}, mesh = {*Pseudomonas aeruginosa/genetics ; *Biofilms ; Bacterial Adhesion ; Culture Media ; Bacterial Proteins/genetics ; }, abstract = {To better understand the impact of biomaterial mechanical properties and growth medium on bacterial adhesion and biofilm formation under flow, we investigated the biofilm formation ability of Pseudomonas aeruginosa in different media on polydimethylsiloxane (PDMS) of different stiffness in real time using a microfluidic platform. P. aeruginosa colonization was recorded with optical microscopy and automated image analysis. The bacterial intracellular level of cyclic diguanylate (c-di-GMP), which regulates biofilm formation, was monitored using the transcription of the putative adhesin gene (cdrA) as a proxy. Contrary to the previous supposition, we revealed that PDMS material stiffness within the tested range has negligible impact on biofilm development and biofilm structures, whereas culture media not only influence the kinetics of biofilm development but also affect the biofilm morphology and structure dramatically. Interestingly, magnesium rather than previously reported calcium was identified here to play a decisive role in the formation of dense P. aeruginosa aggregates and high levels of c-di-GMP. These results demonstrate that although short-term adhesion assays bring valuable insight into bacterial and material interactions, long-term evaluations are essential to better predict overall biofilm outcome. The microfluidic system developed here presents a valuable application potential for studying biofilm development in situ. .}, } @article {pmid36599074, year = {2023}, author = {Cuzzucoli Crucitti, V and Ilchev, A and Moore, JC and Fowler, HR and Dubern, JF and Sanni, O and Xue, X and Husband, BK and Dundas, AA and Smith, S and Wildman, JL and Taresco, V and Williams, P and Alexander, MR and Howdle, SM and Wildman, RD and Stockman, RA and Irvine, DJ}, title = {Predictive Molecular Design and Structure-Property Validation of Novel Terpene-Based, Sustainably Sourced Bacterial Biofilm-Resistant Materials.}, journal = {Biomacromolecules}, volume = {24}, number = {2}, pages = {576-591}, pmid = {36599074}, issn = {1526-4602}, support = {103882//Wellcome Trust/United Kingdom ; 103884//Wellcome Trust/United Kingdom ; }, mesh = {*Terpenes/pharmacology ; *Biofilms ; Polymers/chemistry ; Bacteria ; Methacrylates ; }, abstract = {Presented in this work is the use of a molecular descriptor, termed the α parameter, to aid in the design of a series of novel, terpene-based, and sustainable polymers that were resistant to biofilm formation by the model bacterial pathogen Pseudomonas aeruginosa. To achieve this, the potential of a range of recently reported, terpene-derived monomers to deliver biofilm resistance when polymerized was both predicted and ranked by the application of the α parameter to key features in their molecular structures. These monomers were derived from commercially available terpenes (i.e., α-pinene, β-pinene, and carvone), and the prediction of the biofilm resistance properties of the resultant novel (meth)acrylate polymers was confirmed using a combination of high-throughput polymerization screening (in a microarray format) and in vitro testing. Furthermore, monomers, which both exhibited the highest predicted biofilm anti-biofilm behavior and required less than two synthetic stages to be generated, were scaled-up and successfully printed using an inkjet "valve-based" 3D printer. Also, these materials were used to produce polymeric surfactants that were successfully used in microfluidic processing to create microparticles that possessed bio-instructive surfaces. As part of the up-scaling process, a novel rearrangement was observed in a proposed single-step synthesis of α-terpinyl methacrylate via methacryloxylation, which resulted in isolation of an isobornyl-bornyl methacrylate monomer mixture, and the resultant copolymer was also shown to be bacterial attachment-resistant. As there has been great interest in the current literature upon the adoption of these novel terpene-based polymers as green replacements for petrochemical-derived plastics, these observations have significant potential to produce new bio-resistant coatings, packaging materials, fibers, medical devices, etc.}, } @article {pmid36597590, year = {2023}, author = {El-Sayed, MH and Alshammari, FA and Sharaf, MH}, title = {Antagonistic Potentiality of Actinomycete-Derived Extract with Anti-Biofilm, Antioxidant, and Cytotoxic Capabilities as a Natural Combating Strategy for Multidrug-Resistant ESKAPE Pathogens.}, journal = {Journal of microbiology and biotechnology}, volume = {33}, number = {1}, pages = {61-74}, pmid = {36597590}, issn = {1738-8872}, mesh = {*Actinobacteria/metabolism ; Antioxidants/pharmacology/chemistry ; RNA, Ribosomal, 16S/genetics ; Anti-Bacterial Agents/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology/chemistry ; }, abstract = {The global increase in multidrug-resistant (MDR) bacteria has inspired researchers to develop new strategies to overcome this problem. In this study, 23 morphologically different, soil-isolated actinomycete cultures were screened for their antibacterial ability against MDR isolates of ESKAPE pathogens. Among them, isolate BOGE18 exhibited a broad antibacterial spectrum, so it was selected and identified based on cultural, morphological, physiological, and biochemical characteristics. Chemotaxonomic analysis was also performed together with nucleotide sequencing of the 16S rRNA gene, which showed this strain to have identity with Streptomyces lienomycini. The ethyl acetate extract of the cell-free filtrate (CFF) of strain BOGE18 was evaluated for its antibacterial spectrum, and the minimum inhibitory concentration (MIC) ranged from 62.5 to 250 μg/ml. The recorded results from the in vitro anti-biofilm microtiter assay and confocal laser scanning microscopy (CLSM) of sub-MIC concentrations revealed a significant reduction in biofilm formation in a concentration-dependent manner. The extract also displayed significant scavenging activity, reaching 91.61 ± 4.1% and 85.06 ± 3.14% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. A promising cytotoxic ability against breast (MCF-7) and hepatocellular (HePG2) cancer cell lines was obtained from the extract with IC50 values of 47.15 ± 13.10 and 122.69 ± 9.12 μg/ml, respectively. Moreover, based on gas chromatography-mass spectrometry (GC-MS) analysis, nine known compounds were detected in the BOGE18 extract, suggesting their contribution to the multitude of biological activities recorded in this study. Overall, Streptomyces lienomycini BOGE18-derived extract is a good candidate for use in a natural combating strategy to prevent bacterial infection, especially by MDR pathogens.}, } @article {pmid36597191, year = {2023}, author = {Vasconcelos, BM and Pereira, AMG and Coelho, PAT and Cavalcante, RMB and Carneiro-Torres, DS and Bandeira, PN and da Silva, FF and Rodrigues, THS and Gomes, GA and Carneiro, VA}, title = {Enhancement of chlorhexidine activity against planktonic and biofilm forms of oral streptococci by two Croton spp. essential oils from the Caatinga biome.}, journal = {Biofouling}, volume = {}, number = {}, pages = {1-10}, doi = {10.1080/08927014.2022.2159393}, pmid = {36597191}, issn = {1029-2454}, abstract = {This work investigates the ability of two Croton spp. essential oils (EO) to enhance chlorhexidine (CHX) activity against oral streptococci. EO's chemical composition of Croton argyrophyllus and C. pluriglandulosus was determined by GC-MS/FID. The microbial growth kinetics and minimum inhibitory concentration (MIC) of EOs and CHX were determined, followed by their synergism against S. mutans UA159 and ATCC 25175, S. salivarius ATCC 7073 and S. sp. ATCC 15300. The microplate-based method was used to determine the EO/CHX activity against 24-h-old biofilms. The major compounds were α-pinene (54.74%) and bicyclogermacrene (16.08%) for EOAr and 1,8-cineole (17.41%), methyleugenol (16.06%) and elemicin (15.99%) for EOPg. Both EO had MIC around 16,000 µg/mL. EOs/CHX presented a synergistic effect against most strains (FICi from 0.133 to 0.375), and OE/CHX-treated biofilms showed a reduction in biomass and cell viability compared to CHX, only (p < 0.01). Thus, the EOs works as natural adjuvants for CHX.}, } @article {pmid36596419, year = {2023}, author = {Niu, SM and Zhang, Q and Sangeetha, T and Chen, L and Liu, LY and Wu, P and Zhang, C and Yan, WM and Liu, H and Cui, MH and Wang, AJ}, title = {Evaluation of the effect of biofilm formation on the reductive transformation of triclosan in cathode-modified electrolytic systems.}, journal = {The Science of the total environment}, volume = {865}, number = {}, pages = {161308}, doi = {10.1016/j.scitotenv.2022.161308}, pmid = {36596419}, issn = {1879-1026}, mesh = {*Triclosan ; Electrolysis ; Electrodes ; Biofilms ; *Nanotubes, Carbon/chemistry ; Platinum ; }, abstract = {The performance of electrochemical reduction is often enhanced by electrode modification techniques. However, there is a risk of microbial colonization on the electrode surface to form biofilms in the treatment of actual wastewater with modified electrodes. In this work, the effects of biofilm formation on modified electrodes with reduced graphene oxide (rGO), platinum/carbon (Pt/C), and carbon nanotube (CNT) were investigated in triclosan (TCS) degradation. With biofilm formation, the TCS degradation efficiencies of carbon cloth (CC), rGO@CC, Pt/C@CC, and CNT@CC decayed to 54.53 %, 59.77 %, 69.19 %, and 53.97 %, respectively, compared to the raw electrodes. Confocal laser scanning microscopy and microbial community analysis revealed that the difference in biofilm thickness and activity were the major influencing factors on the discrepant TCS degradation rather than the microbial community structure. The electrochemical performance tests showed that the biofilm formation increased the ohmic resistance by an order of magnitude in rGO@CC, Pt/C@CC, and CNT@CC, and the charge transfer resistance was increased by 2.45, 3.78, and 7.75 times, respectively. The dechlorination and hydrolysis governed the TCS degradation pathway in all electrolysis systems, and the toxicity of electrochemical reductive products was significantly decreased according to the Toxicity Estimation Software Tool analysis. This study presented a systematic assessment of the biofilm formation on modified electrodes in TCS reduction, and the undisputed experimental outcomes were obtained to enrich the knowledge of implementing modified electrodes for practical applications.}, } @article {pmid36595339, year = {2023}, author = {Hashemifard Dehkordi, P and Moshtaghi, H and Abbasvali, M}, title = {Effects of magnesium oxide and copper oxide nanoparticles on biofilm formation ofEscherichia coliandListeria monocytogenes.}, journal = {Nanotechnology}, volume = {34}, number = {15}, pages = {}, doi = {10.1088/1361-6528/acab6f}, pmid = {36595339}, issn = {1361-6528}, mesh = {*Magnesium Oxide/pharmacology ; Copper/pharmacology ; Food Microbiology ; Colony Count, Microbial ; Biofilms ; Bacteria ; *Nanoparticles ; }, abstract = {Biofilms formed in food-processing environments are of special importance as they have the potential to act as a persistent source of microbial contamination that may lead to food spoilage or transmission of diseases. The creation of microbial biofilms, which can be a source of food product contamination with food spoilage and foodborne pathogenic bacteria, is one of the most critical elements in the food industry. The goal of this study was to see how well magnesium oxide (MgO) and copper oxide (CuO) nanoparticles (NPs) inhibited growth and biofilm formation of two common foodborne bacterial pathogens. This study was completed in the year 2020. Resazurin reduction and micro-dilution procedures were used to assess the minimum inhibitory concentration (MIC) of magnesium oxide and copper oxide nanoparticles forEscherichia coliO157: H7 (ATCC 35 218) andListeria monocytogenes(L. monocytogenes) (ATCC 19 118). The bacterial adhesion to hydrocarbon technique was used to determine the cell-surface hydrophobicity of the selected bacteria. The surface assay was also used to calculate the influence of the NPs coated surfaces on the biofilm formation of the selected bacteria. Magnesium oxide nanoparticles had MICs of 2 and 2 mg ml[-1], while copper oxide nanoparticles had MICs of 0.16 and 1 mg ml[-1]againstE. coliandL. monocytogenes, respectively. At the MIC, the magnesium and copper nanoparticles inhibited biofilm formation ofE. coliandL. monocytogenesby 89.9 and 96.6 percent and 93.6 and 98.7 percent, respectively. The hydrophobicity ofE. coliandL. monocytogeneswas determined to be 74% and 67%, respectively. The surface assay revealed a substantial reduction in bacterial adhesion and colonization on NPs-coated surfaces. Both compounds had inhibitory effects onE. coliandL. monocytogenes, according to our findings. Even at sub-MICs, NPs were found to be able to prevent biofilm development. The microbial count and production of microbial biofilms were reduced on surfaces coated with MgO and CuO nanoparticles. MgO and CuO nanoparticles can be utilized as a cleaning agent for surfaces to avoid the formation of foodborne bacterial biofilms, which is important for public health.}, } @article {pmid36593358, year = {2023}, author = {Mahgoub, MA and Abbass, AAG and Abaza, AF and Shoukry, MS}, title = {Probiotic lactic acid bacteria as a means of preventing in vitro urinary catheter colonization and biofilm formation.}, journal = {The Journal of the Egyptian Public Health Association}, volume = {97}, number = {1}, pages = {30}, pmid = {36593358}, issn = {0013-2446}, abstract = {BACKGROUND: Catheter-associated urinary tract infections (CAUTIs) are the most common infections found in healthcare facilities. Urinary catheters predispose the development of CAUTIs by destroying natural barriers and providing a source for infection and biofilm formation (BF). This study aimed to evaluate probiotic lactic acid bacteria (LAB) as a means of preventing in vitro urinary catheter colonization and BF.

METHODS: Cross-sectional screening, followed by an experimental study, was conducted on 120 catheterized patients admitted to the urology department in a tertiary care hospital for 7 months. The isolated and identified uropathogens were tested for their antimicrobial susceptibility patterns by the disk diffusion method according to Clinical and Laboratory Standards Institute recommendations and examined for their ability to produce biofilms using a microtiter plate (MtP) assay. Five LAB (Lactobacillus acidophilus (L. acidophilus), Bifidobacterium bifidum (B. bifidum), L. paracasei, L. pentosus, and L. plantarum) were identified and examined for preventing in vitro colonization and BF of some isolated uropathogens on Foley urinary catheter surfaces.

RESULTS: Of the 120 samples collected, 32.5% were found to be associated with CAUTIs. Of isolated organisms, 74.4% were gram-negative bacilli, while gram-positive cocci represented 14%, and only 11.6% were of the Candida species. About two-thirds of isolated uropathogens were biofilm formers. All five probiotic strains had inhibitory effects on the growth of all the uropathogens tested but with varying intensities according to the duration of application after 2, 4, and 6 days.

CONCLUSIONS: The prevalence of CAUTIs was high, and the predominant bacterial isolates were gram-negative bacilli. Many of the studied uropathogens were biofilm formers. The bacterial isolates had a higher prevalence of resistance to commonly prescribed antimicrobial agents. Probiotics have the potential to prevent in vitro urinary catheter colonization and inhibit BF. Pre-coating urinary catheters with probiotics is recommended after ensuring the safety of probiotics' use in vivo by carrying out further large-scale studies.}, } @article {pmid36592830, year = {2023}, author = {Tong, CY and Chua, MX and Tan, WH and Derek, CJC}, title = {Microalgal extract as bio-coating to enhance biofilm growth of marine microalgae on microporous membranes.}, journal = {Chemosphere}, volume = {315}, number = {}, pages = {137712}, doi = {10.1016/j.chemosphere.2022.137712}, pmid = {36592830}, issn = {1879-1298}, mesh = {*Microalgae/metabolism ; Biofilms ; Extracellular Polymeric Substance Matrix ; Polysaccharides/metabolism ; Proteins/metabolism ; Plant Extracts ; }, abstract = {Microalgal biofilm is a popular platform for algal production, nutrient removal and carbon capture; however, it suffers from significant biofilm exfoliation under shear force exposure. Hence, a biologically-safe coating made up of algal extracellular polymeric substances (EPS) was utilized to secure the biofilm cell retention and cell loading on commercial microporous membrane (polyvinylidene fluoride), making the surfaces more hydrophobic (contact angle increase up to 12°). Results demonstrated that initial cell adhesion of three marine microalgae (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta) was enhanced by at least 1.3 times higher than that of pristine control within only seven days with minimized biofilm exfoliation issue due to uniform distribution of sticky transparent exopolymer particles. Bounded extracellular polysaccharide gathered was approximately 23% higher on EPS-coated membranes to improve the biofilm's hydraulic resistance, whereas bounded extracellular protein would only be substantially elevated after the attached cells re-accommodate themselves onto the EPS pre-coating of themselves. In accounting the rises of hydrophobic protein content, biofilm was believed to be more stabilized, presumably via hydrophobic interactions. EPS biocoating would generate a groundswell of interest for bioprocess intensifications though there are lots of inherent technical and molecular challenges to be further investigated in future.}, } @article {pmid36592808, year = {2023}, author = {Lan, M and Yin, Q and Wang, J and Li, M and Li, Y and Li, B}, title = {Heterotrophic nitrification-aerobic denitrification performance of a novel strain, Pseudomonas sp. B-1, isolated from membrane aerated biofilm reactor.}, journal = {Environmental research}, volume = {220}, number = {}, pages = {115199}, doi = {10.1016/j.envres.2022.115199}, pmid = {36592808}, issn = {1096-0953}, mesh = {*Nitrification ; *Denitrification ; Pseudomonas/genetics/metabolism ; Aerobiosis ; Nitrogen/metabolism ; Biofilms ; Nitrites/metabolism ; }, abstract = {A heterotrophic nitrification-aerobic denitrification (HN-AD) strain isolated from membrane aerated biofilm reactor (MABR) was identified as Pseudomonas sp. B-1, which could effectively utilize multiple nitrogen sources and preferentially consume NH4-N. The maximum degradation efficiencies of NO3-N, NO2-N and NH4-N were 98.04%, 94.84% and 95.74%, respectively. The optimal incubation time, shaking speed, carbon source, pH, temperature and C/N ratio were 60 h, 180 rpm, sodium succinate, 8, 30 °C and 25, respectively. The strain preferred salinity of 1.5% and resisted heavy metals in the order of Mn[2+] > Co[2+] > Zn[2+] > Cu[2+]. It can be preliminarily speculated from the results of enzyme assay that the strain removed nitrogen via full nitrification-denitrification pathway. The addition of strain into the conventional MABR significantly intensified the HN-AD performance of the reactor. The relative abundance of the functional bacteria including Flavobacterium, Pseudomonas, Paracoccus, Azoarcus and Thauera was obviously increased after the bioaugmentation. Besides, the expression of the HN-AD related genes in the biofilm was also strengthened. Thus, strain B-1 had great application potential in nitrogen removal process.}, } @article {pmid36592641, year = {2023}, author = {Upadhyay, A and Pal, D and Kumar, A}, title = {Substantial relation between the bacterial biofilm and oncogenesis progression in host.}, journal = {Microbial pathogenesis}, volume = {175}, number = {}, pages = {105966}, doi = {10.1016/j.micpath.2022.105966}, pmid = {36592641}, issn = {1096-1208}, mesh = {Humans ; *Biofilms ; Bacteria ; *Bacterial Infections/drug therapy ; Drug Resistance, Microbial ; Carcinogenesis ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Globally, bacteria are well-known microorganisms for bacterial biofilm infection. Bacterial biofilm has generated antibiotic resistance and led the persistent infection. But new complications arise with a biofilm that bacterial biofilm shows the new association with oncogenesis. Some bacteria have a carcinogenic nature at the chronic infection stage like Salmonella Typhi, Helicobacter pylori. Thus, biofilm has a significant role in oncogenesis. Few pieces of evidence also support that the bacterial biofilm has a potential role to develop oncogenesis in the human body. Bacterial biofilm is responsible to induce chronic inflammation and is the main basis for the oncogenesis process. But bacterial biofilm association with the oncogenesis mechanism is unknown yet. This article focuses on the function of bacterial biofilm in tumor formation and the mechanism that encourages the oncogenesis and provide a possible and interesting hypothesis involved in between biofilm and host oncogenesis progression. The discussed relationship will provide a sound direction in the field of oncology and concept may give an informative direction in diagnosis and treatment. Bacterial biofilm behavior could be significantly linked with cancer cell formation. This article attracts the attention of researchers of the field because biofilm mediated oncogenesis further indicate towards an important issue in human health.}, } @article {pmid36590419, year = {2022}, author = {Xie, Y and Wang, L and Yang, Y and Zha, L and Zhang, J and Rong, K and Tang, W and Zhang, J}, title = {Antibacterial and anti-biofilm activity of diarylureas against Enterococcus faecium by suppressing the gene expression of peptidoglycan hydrolases and adherence.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1071255}, pmid = {36590419}, issn = {1664-302X}, abstract = {Enterococcus faecium (E. faecium) is a clinical multidrug-resistant pathogen causing life-threatening infection, which makes it important to discover antibacterial agents with novel scaffolds and unique mechanism. In this study, the diarylurea scaffold was found to have potent antibacterial effect on E. faecium. Diarylurea ZJ-2 with benign drug-like property exhibited potent antibacterial and anti-biofilm activity through inhibiting the genes expression of NlpC/p60 hydrolase-secreted antigen A (sagA) and autolysins (atlA), down-regulating the expression of biofilm adherence related genes aggregation substance (agg), enterococcal surface protein (esp) against E. faecium. Moreover, ZJ-2 can be docked into SagA to inhibit daughter cell separation. In a mouse model of abdominal infection, ZJ-2 decreased the bacterial load and the level of IL-6 and TNF-α in a time-dependent manner. Overall, these findings indicated that diarylurea ZJ-2 has the potential to be developed as a therapeutic agent to treat drug-resistant enterococci and biofilm-related infections.}, } @article {pmid36589237, year = {2022}, author = {Song, N and De Greve, H and Wang, Q and Hernalsteens, JP and Li, Z}, title = {Plasmid parB contributes to uropathogenic Escherichia coli colonization in vivo by acting on biofilm formation and global gene regulation.}, journal = {Frontiers in molecular biosciences}, volume = {9}, number = {}, pages = {1053888}, pmid = {36589237}, issn = {2296-889X}, abstract = {The endogenous plasmid pUTI89 harbored by the uropathogenic Escherichia coli (UPEC) strain UTI89 plays an important role in the acute stage of infection. The partitioning gene parB is important for stable inheritance of pUTI89. However, the function of partitioning genes located on the plasmid in pathogenesis of UPEC still needs to be further investigated. In the present study, we observed that disruption of the parB gene leads to a deficiency in biofilm formation in vitro. Moreover, in a mixed infection with the wild type strain and the parB mutant, in an ascending UTI mouse model, the mutant displayed a lower bacterial burden in the bladder and kidneys, not only at the acute infection stage but also extending to 72 hours post infection. However, in the single infection test, the reduced colonization ability of the parB mutant was only observed at six hpi in the bladder, but not in the kidneys. The colonization capacity in vivo of the parB-complemented strain was recovered. qRT-PCR assay suggested that ParB could be a global regulator, influencing the expression of genes located on both the endogenous plasmid and chromosome, while the gene parA or the operon parAB could not. Our study demonstrates that parB contributes to the virulence of UPEC by influencing biofilm formation and proposes that the parB gene of the endogenous plasmid could regulate gene expression globally.}, } @article {pmid36588982, year = {2023}, author = {Shaikh, S and Rashid, N and Onwusogh, U and McKay, G and Mackey, HR}, title = {Effect of nutrients deficiency on biofilm formation and single cell protein production with a purple non-sulphur bacteria enriched culture.}, journal = {Biofilm}, volume = {5}, number = {}, pages = {100098}, pmid = {36588982}, issn = {2590-2075}, abstract = {Purple non-sulphur bacteria (PNSB) are of interest for biorefinery applications to create biomolecules, but their production cost is expensive due to substrate and biomass separation costs. This research has utilized fuel synthesis wastewater (FSW) as a low-cost carbon-rich substrate to produce single-cell protein (SCP) and examines PNSB biofilm formation using this substrate to achieve a more efficient biomass-liquid separation. In this study, PNSB were grown in Ca, Mg, S, P, and N-deficient media using green shade as biofilm support material. Among these nutrient conditions, only N-deficient and control (nutrient-sufficient) conditions showed biofilm formation. Although total biomass growth of the control was 1.5 times that of the N-deficient condition and highest overall, the total biofilm-biomass in the N-deficient condition was 2.5 times greater than the control, comprising 49% of total biomass produced. Total protein content was similar between these four biomass samples, ranging from 35.0 ± 0.2% to 37.2 ± 0.0%. The highest protein content of 44.7 ± 1.3% occurred in the Mg-deficient condition (suspended biomass only) but suffered from a low growth rate. Overall, nutrient sufficient conditions are optimal for overall protein productivity and dominated by suspended growth, but where fixed growth systems are desired for cost-effective harvesting, N-deficient conditions provide an effective means to maximize biofilm production without sacrificing protein content.}, } @article {pmid36588392, year = {2023}, author = {Rezaei, T and Kamounah, FS and Khodadadi, E and Mehramouz, B and Gholizadeh, P and Yousefi, L and Ganbarov, K and Ghotaslou, R and Yousefi, M and Asgharzadeh, M and Eslami, H and Taghizadeh, S and Pirzadeh, T and Kafil, HS}, title = {Comparing proteome changes involved in biofilm formation by Streptococcus mutans after exposure to sucrose and starch.}, journal = {Biotechnology and applied biochemistry}, volume = {70}, number = {3}, pages = {1320-1331}, doi = {10.1002/bab.2442}, pmid = {36588392}, issn = {1470-8744}, support = {67426//Drug Applied Research Center/ ; }, mesh = {*Starch/pharmacology/metabolism ; *Sucrose/pharmacology/metabolism ; Streptococcus mutans ; Proteome/metabolism ; Biofilms ; }, abstract = {Streptococcus mutans is a main organism of tooth infections including tooth decay and periodontitis. The aim of this study was to assess the influence of sucrose and starch on biofilm formation and proteome profile of S. mutans ATCC 35668 strain. The biofilm formation was assessed by microtiter plating method. Changes in bacterial proteins after exposure to sucrose and starch carbohydrates were analyzed using matrix-assisted laser desorption/ionization mass spectrometry. The biofilm formation of S. mutans was increased to 391.76% in 1% sucrose concentration, 165.76% in 1% starch, and 264.27% in the 0.5% sucrose plus 0.5% starch in comparison to biofilm formation in the media without sugars. The abundance of glutamines, adenylate kinase, and 50S ribosomal protein L29 was increased under exposure to sucrose. Upregulation of lactate utilization protein C, 5-hydroxybenzimidazole synthase BzaA, and 50S ribosomal protein L16 was formed under starch exposure. Ribosome-recycling factor, peptide chain release factor 1, and peptide methionine sulfoxide reductase MsrB were upregulated under exposure to sucrose in combination with starch. The results demonstrated that the carbohydrates increase microbial pathogenicity. In addition, sucrose and starch carbohydrates can induce biofilm formation of S. mutans via various mechanisms such as changes in the expression of special proteins.}, } @article {pmid36587926, year = {2023}, author = {Siqueira, FDS and Siqueira, JD and Denardi, LB and Moreira, KS and Lima Burgo, TA and de Lourenço Marques, L and Machado, AK and Davidson, CB and Chaves, OA and Anraku de Campos, MM and Back, DF}, title = {Antibacterial, antifungal, and anti-biofilm effects of sulfamethoxazole-complexes against pulmonary infection agents.}, journal = {Microbial pathogenesis}, volume = {175}, number = {}, pages = {105960}, doi = {10.1016/j.micpath.2022.105960}, pmid = {36587926}, issn = {1096-1208}, mesh = {*Sulfamethoxazole/pharmacology ; *Antifungal Agents/pharmacology ; Molecular Docking Simulation ; Anti-Bacterial Agents/chemistry ; Biofilms ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, abstract = {Antibiotic resistance associated with pulmonary infection agents has become a public health problem, being considered one of the main priorities for immediate resolution. Thus, to increase the therapeutic options in the fight against resistant microorganisms, the synthesis of molecules from pre-existing drugs has shown to be a promising alternative. In this sense, the present work reports the synthesis, characterization, and biological evaluation (against fungal and bacterial agents that cause lung infections) of potential metallodrugs based on sulfamethoxazole complexed with Au[I], Ag[I], Hg[II], Cd[II], Ni[II], and Cu[II]. The minimal inhibitory concentration (MIC) value was used to evaluate the antifungal and antibacterial properties of the compounds. In addition, it was also evaluated the antibiofilm capacity in Pseudomonas aeruginosa, through the quantification of its biomass and visualization using atomic force microscopy. For each case, molecular docking calculations were carried out to suggest the possible biological target of the assayed inorganic complexes. Our results indicated that the novel inorganic complexes are better antibacterial and antifungal than the commercial antibiotic sulfamethoxazole, highlighting the Ag[I]-complex, which was able to inhibit the growth of microorganisms that cause lung diseases with concentrations in the 2-8 μg mL[-1] range, probably at targeting dihydropteroate synthetase - a key enzyme involved in the folate synthesis. Furthermore, sulfamethoxazole complexes were able to inhibit the formation of bacterial biofilms at significantly lower concentrations than free sulfamethoxazole, probably mainly targeting the active site of LysR-type transcriptional regulator (PqsR). Overall, the present study reports preliminary results that demonstrate the derivatization of sulfamethoxazole with transition metal cations to obtain potential metallodrugs with applications as antimicrobial and antifungal against pulmonary infections, being an alternative for drug-resistant strains.}, } @article {pmid36587206, year = {2022}, author = {Li, R and Liang, Q and Tian, S and Zhang, Y and Liu, S and Ou, Q and Chen, Z and Wang, C}, title = {Hemolysin function of Listeria is related to biofilm formation: transcriptomics analysis.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {113}, pmid = {36587206}, issn = {1297-9716}, support = {31570924//National Natural Science Foundation of China/ ; 2021YFQ0060//Key Program of Sichuan Science and Technology Department/ ; 2021YFS0005//Key Program of Sichuan Science and Technology Department/ ; }, mesh = {Animals ; *Listeria/genetics/metabolism ; Hemolysin Proteins/genetics ; Transcriptome ; *Listeria monocytogenes/genetics ; Biofilms ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Listeriolysin O (LLO) is the main virulence protein of Listeria monocytogenes (LM), that helps LM escape lysosomes. We previously found that the cellular immune response elicited by L.ivanovii (LI) is weaker than that elicited by LM. We speculated that this may be related to the function of ivanolysin O (ILO). Here, we constructed hemolysin gene deletion strain, LIΔilo, and a modified strain, LIΔilo::hly, in which ilo was replaced by hly. Prokaryotic transcriptome sequencing was performed on LI, LIΔilo, and LIΔilo::hly. Transcriptome differences between the three strains were compared, and genes and pathways with significant differences between the three strains were analyzed. Prokaryotic transcriptome sequencing results revealed the relationship of ilo to the ribosome, quorum sensing, and phosphotransferase system (PTS) pathways, etc. LIΔilo exhibited attenuated biofilm formation ability compared to LI. Biofilm formation was significantly recovered or even increased after replenishing hly. After knocking out ilo, the relative expression levels of some virulence genes, including sigB, prfA, actA, smcL, and virR, were up-regulated compared to LI. After replenishing hly, these genes were down-regulated compared to LIΔilo. The trend and degree of such variation were not completely consistent when cultured in media containing only monosaccharides or disaccharides. The results confirmed that hemolysin is related to some important biological properties of Listeria, including biofilm formation and virulence gene expression levels. This is the first comprehensive study on ILO function at the transcriptomic level and the first evidence of a relationship between Listeria hemolysin and biofilm formation.}, } @article {pmid36586714, year = {2023}, author = {Zhao, ZC and Fan, SQ and Lu, Y and Dang, CC and Wang, X and Liu, BF and Xing, DF and Ma, J and Ren, NQ and Wang, Q and Xie, GJ}, title = {Reactivated biofilm coupling n-DAMO with anammox achieved high-rate nitrogen removal in membrane aerated moving bed biofilm reactor.}, journal = {Environmental research}, volume = {220}, number = {}, pages = {115184}, doi = {10.1016/j.envres.2022.115184}, pmid = {36586714}, issn = {1096-0953}, mesh = {*Nitrates ; Denitrification ; Methane ; Nitrogen ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; *Ammonium Compounds ; Bioreactors/microbiology ; Oxidation-Reduction ; Biofilms ; }, abstract = {As a promising technology, the combination of nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) with Anammox offers a solution to achieve effective and sustainable wastewater treatment. However, this sustainable process faces challenges to accumulate sufficient biomass for reaching practical nitrogen removal performance. This study developed an innovative membrane aerated moving bed biofilm reactor (MAMBBR), which supported sufficient methane supply and excellent biofilm attachment, for cultivating biofilms coupling n-DAMO with Anammox. Biofilms were developed rapidly on the polyurethane foam with the supply of ammonium and nitrate, achieving the bioreactor performance of 275 g N m[-3] d[-1] within 102 days. After the preservation at -20 °C for 8 months, the biofilm was successfully reactivated and achieved 315 g N m[-3] d[-1] after 188 days. After reactivation, MAMBBR was applied to treat synthetic sidestream wastewater. Up to 99.9% of total nitrogen was removed with the bioreactor performance of 4.0 kg N m[-3] d[-1]. Microbial community analysis and mass balance calculation demonstrated that n-DAMO microorganisms and Anammox bacteria collectively contributed to nitrogen removal in MAMBBR. The MAMBBR developed in this study provides an ideal system of integrating n-DAMO with Anammox for sustainable wastewater treatment.}, } @article {pmid36586294, year = {2023}, author = {Fu, D and Wu, J and Wu, X and Shao, Y and Song, X and Tu, J and Qi, K}, title = {The two-component system histidine kinase EnvZ contributes to Avian pathogenic Escherichia coli pathogenicity by regulating biofilm formation and stress responses.}, journal = {Poultry science}, volume = {102}, number = {2}, pages = {102388}, pmid = {36586294}, issn = {1525-3171}, mesh = {Animals ; Escherichia coli/physiology ; Histidine Kinase/metabolism ; Virulence ; *Escherichia coli Proteins/genetics/metabolism ; *Escherichia coli Infections/veterinary ; Chickens/metabolism ; Biofilms ; *Poultry Diseases ; Bacterial Outer Membrane Proteins/metabolism ; Multienzyme Complexes/metabolism ; }, abstract = {EnvZ, the histidine kinase (HK) of OmpR/EnvZ, transduces osmotic signals in Escherichia coli K12 and affects the pathogenicity of Shigella flexneri and Vibrio cholera. Avian pathogenic E. coli (APEC) is an extra-intestinal pathogenic E. coli (ExPEC), causing acute and sudden death in poultry and leading to severe economic losses to the global poultry industry. How the functions of EnvZ correlate with APEC pathogenicity was still unknown. In this study, we successfully constructed the envZ mutant strain AE17ΔenvZ and the inactivation of envZ significantly reduced biofilms and altered red, dry, and rough (rdar) morphology. In addition, AE17ΔenvZ was significantly less resistant to acid, alkali, osmotic, and oxidative stress conditions. Deletion of envZ significantly enhanced sensitivity to specific pathogen-free (SPF) chicken serum and increased adhesion to chicken embryonic fibroblast DF-1 cells and elevated inflammatory cytokine IL-1β, IL6, and IL8 expression levels. Also, when compared with the WT strain, AE17ΔenvZ attenuated APEC pathogenicity in chickens. To explore the molecular mechanisms underpinning envZ in APEC17, we compared the WT and envZ-deletion strains using transcriptome analyses. RNA-Seq results identified 711 differentially expressed genes (DEGs) in the envZ mutant strain and DEGs were mainly enriched in outer membrane proteins, stress response systems, and TCSs. Quantitative real-time reverse transcription PCR (RT-qPCR) showed that EnvZ influenced the expression of biofilms and stress responses genes, including ompC, ompT, mlrA, basR, hdeA, hdeB, adiY, and uspB. We provided compelling evidence showing EnvZ contributed to APEC pathogenicity by regulating biofilms and stress response expression.}, } @article {pmid36586061, year = {2022}, author = {Ankudze, B and Neglo, D}, title = {Green synthesis of silver nanoparticles from peel extract of Chrysophyllum albidum fruit and their antimicrobial synergistic potentials and biofilm inhibition properties.}, journal = {Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine}, volume = {}, number = {}, pages = {}, pmid = {36586061}, issn = {1572-8773}, abstract = {Current methods for green synthesis of metal nanoparticles often require continuous harvesting of fresh bio-materials for every synthesis cycle. Practices and procedures that economize bio-materials need to be employed if green synthesis could become a sustainable and eco-friendly method for synthesizing metal nanoparticles. This study explores Chrysophyllum albidum peels (mostly regarded as waste) to prepare silver nanoparticles (Alb-AgNPs). The technique employed in the synthesis allows repeated use of the peels, thus, reducing the heavy dependence on bio-materials. The optical and structural properties of the Alb-AgNPs were studied with Scanning electron microscope, Fourier transform infrared spectrometer, UV-Vis spectrophotometer and powder X-ray diffractometer. The antimicrobial properties of the Alb-AgNPs were studied with selected microorganisms namely; S. aureus, E. coli, K. pneumoniae, B. subtilis, S. mutans, P. aeruginosa, S. typhi, and Candida albicans. High inhibitory activity against the microorganisms were exhibited with MICs ranging from 15.62 to 1000 µg/mL. Again, the Alb-AgNPs showed the ability to enhance the efficacy of standard antimicrobial agents. The results of the combined interaction with standard antibacterial and antifungal agents ranged from synergistic to antagonistic effects against the tested microorganisms. In addition, the Alb-AgNPs could serve as a biofilm inhibitor with the highest percent inhibition of about 92% against methicillin-resistant Staphylococcus aureus. The results from this study thus provide access to the simple, sustainable, economic and eco-friendly synthesis of silver nanoparticles with efficient antimicrobial properties as drug candidates as a means of overcoming the prevailing antibiotic resistance menaces.}, } @article {pmid36585632, year = {2022}, author = {Hamed, SA and Shabayek, S and Hassan, HY}, title = {Biofilm elimination from infected root canals using four different single files.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {660}, pmid = {36585632}, issn = {1472-6831}, mesh = {Humans ; Biofilms ; *Dental Pulp Cavity/microbiology ; Enterococcus faecalis ; Pilot Projects ; Root Canal Irrigants ; *Root Canal Preparation ; Root Canal Therapy ; }, abstract = {INTRODUCTION: Enterococcus faecalis (E. faecalis) is the most commonly isolated bacterium from infected root canals. It is found in the form of a biofilm, which makes it more resistant to antimicrobials, and requires optimal chemomechanical strategies to maximize root canal disinfection.

AIM: To evaluate the efficacy of 4 different endodontic file systems against E. faecalis biofilm growth in root canals using colony-forming units per milliliter (CFU/mL) and scanning electron microscope (SEM).

METHODS: Eighty-five extracted human mandibular premolars with straight root canals and apical diameters not larger than the #15 K-file were randomly selected. After performing a pilot study (n = 15) to determine the ideal incubation period for E. faecalis biofilm development, sixty-five root canals were infected with E. faecalis, incubated for 3 weeks, and then mechanically prepared using one of four single files (XP-endo Shaper, Hyflex EDM, One Curve, and Fanta. AFTM F One) (n = 15). Five infected root canals were excluded for the positive control. Five non-contaminated root canals were included for the negative control. Samples were collected using sterile paper points pre- and post-instrumentation to determine the bacterial load (CFU/mL). Root canals from each group were topographically evaluated at the coronal, middle, and apical segments using scanning electron microscope (SEM). Bacterial reduction data were estimated and statistically analyzed by Kruskal-Wallis and Mann-Whitney U tests (post hoc test) (P ≤ .05).

RESULTS: XP-endo Shaper, Hyflex DEM, and One Curve significantly could eradicate E. faecalis biofilms in infected root canals with no significant difference among them compared to Fanta. AF™ F One.

CONCLUSION: None of the systems were capable of completely eliminating biofilms. XP-endo Shaper, Hyflex EDM, and One Curve mechanically eliminated E. faecalis biofilms compared to Fanta. AF™ F One from infected root canals.}, } @article {pmid36585548, year = {2023}, author = {Salimi, F and Imanparast, S}, title = {Characterization of Probiotic Pichia sp. DU2-Derived Exopolysaccharide with Oil-in-Water Emulsifying and Anti-biofilm Activities.}, journal = {Applied biochemistry and biotechnology}, volume = {195}, number = {5}, pages = {3345-3365}, pmid = {36585548}, issn = {1559-0291}, mesh = {*Pichia ; Spectroscopy, Fourier Transform Infrared ; Polysaccharides, Bacterial/pharmacology ; Emulsions ; *Probiotics ; Water ; }, abstract = {Probiotic-derived exopolysaccharides are considered as promising sources of carbohydrate with extensive applications in many industries. In the current study, yeast strains were isolated from chicken ingluvies and gizzard samples. According to molecular identification, EPS-producing yeast (Pichia sp. DU2) showed the most similarity to Pichia cactophila (99.67%). Pichia sp. DU2 showed probiotic properties. EPS of Pichia sp. DU2 showed emulsifying activity. The formed emulsions showed 53% (colza oil) and 100% (p-xylene) stability after 24 h. These emulsions were oil-in-water and have stability in the presence of NaCl, KCl, and also acidic and basic conditions. Also, the EPS showed anti-biofilm (29.7-47.6% and 19.06-55.26% against B. cereus and Y. enterocolitica, respectively) and flocculating activities (31.4%). FT-IR showed the presence of various functional groups in EPS structure. Also, its heteropolysaccharide nature was revealed in [1]H-NMR and HPLC analysis. This emulsifying EPS showed significant thermal stability and negative zeta potential, which make it a promising carbohydrate for various industries. Finally, according to the predicted model, the maximal EPS production was achieved at reaction time 36 h, pH 6, yeast extract concentration 1.0%, and sucrose concentration 5%. Pichia sp. DU2 with probiotic properties and producing EPS with emulsifying, anti-biofilm, and flocculating activities can be considered as promising yeast strain in various industries like food and pharmaceutical industries.}, } @article {pmid36585511, year = {2023}, author = {Bai, X and Shen, Y and Zhang, T and Meng, R and Zhang, Y and Deng, Y and Guo, N}, title = {Anti-biofilm activity of biochanin A against Staphylococcus aureus.}, journal = {Applied microbiology and biotechnology}, volume = {107}, number = {2-3}, pages = {867-879}, pmid = {36585511}, issn = {1432-0614}, support = {2018YFC1602202//the National Key Research and Development Program of China/ ; 31772082//the National Natural Science Foundation of China/ ; JJKH20201017KJ//the 13th Five-Year Plan Science and Technology Project of the Education Department of Jilin Province/ ; }, mesh = {*Staphylococcus aureus ; *Extracellular Polymeric Substance Matrix ; Molecular Docking Simulation ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Biofilm-forming Staphylococcus aureus can easily accumulate on various food contact surfaces which induce cross-contamination and are difficult to eliminate in the food industry. This study aimed to evaluate the anti-biofilm effects of natural product biochanin A against S. aureus. Results showed that biochanin A effectively eradicated established S. aureus biofilms on different food-contact materials. Fluorescence microscopic analyses suggested that biochanin A disintegrated the established biofilms by dissociate extracellular polymeric substance (EPS) in matrix. In addition, biochanin A at the sub-MIC concentration also effectively inhibited the biofilm formation by regulating the expression of biofilm-related genes (icaA, srtA, eno) and suppressing the release of EPS in biofilm matrix. Molecular docking also demonstrated that biochanin A conducted strong interactions with biofilm-related proteins (Ica A, Sortase A, and Enolase). These findings demonstrated that biochanin A has the potential to be developed as a potent agent against S. aureus biofilm in food industries. KEY POINTS: • Anti-biofilm effect of biochanin A against S. aureus was revealed for the first time. • Biofilm of S. aureus on various food-contact surfaces were efficiently eradicated. • Biochanin A prevented S. aureus biofilm formation via reducing EPS production.}, } @article {pmid36583292, year = {2022}, author = {Andhare, MG and Shetty, S and Vivekanandan, G and Shetty, RM and Rahman, B and Shetty, SR and Siddeshappa, ST and Desai, V}, title = {Clinical efficacy of green tea, aloe vera and chlorhexidine mouthwashes in the treatment of dental biofilm induced gingivitis: A multi-arm, double-blinded, randomized controlled clinical trial.}, journal = {International journal of dental hygiene}, volume = {}, number = {}, pages = {}, doi = {10.1111/idh.12664}, pmid = {36583292}, issn = {1601-5037}, abstract = {OBJECTIVE: This multi-arm, randomized, double-blinded, controlled clinical trial was designed to evaluate the clinical efficacy of 0.5% green tea (GT), 0.2% chlorhexidine (CHX) and aloe vera (AV) mouthwash as compared to the control (CNT) group (scaling and polishing alone with no mouthwash) in the management of dental biofilm induced gingivitis among 18-40-year-old patients.

MATERIAL AND METHODS: Sixty patients with generalized dental biofilm-induced gingivitis were randomly allocated to four study groups (n = 15 each) for treatment, namely Group GT, Group CHX, Group AV and Group CNT after scaling and polishing were administered to all the patients. Plaque index (PI), gingival index (GI) and sulcular bleeding index (SBI) were recorded at baseline, 14th and 21st day.

RESULTS: PI, GI and SBI at various time intervals (baseline, 14th and 21st day) showed high statistically significant differences within the group (p < 0.01). Among these, the maximum percentage change was found in the CHX group followed by GT when evaluated from baseline to 21st day. The least percentage change was found in the AV group for PI and GI while the CNT group showed the least percentage change for sulcular index when evaluated from 14th to 21st day. Inter-group results showed high statistically significant differences (p < 0.01) for PI and GI when evaluated between baseline to 14th day and baseline to 21st day. SBI also showed statistically significant differences (p < 0.05) when evaluated between baselines to 14th day and baseline to 21st day.

CONCLUSION: Green tea mouthwash displayed a significant reduction in plaque index, gingival index and sulcular bleeding index. 0.5% green tea catechin has equivalent anti-plaque efficacy as 0.2% chlorhexidine gluconate and can be considered a potent alternative to prevent and treat gingival diseases.}, } @article {pmid36583044, year = {2022}, author = {Li, L and Yu, T and Yuan, L and Doulgeraki, AI and Iseppi, R}, title = {Editorial: Biofilm formation and quorum sensing of foodborne microorganism.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1107603}, pmid = {36583044}, issn = {1664-302X}, } @article {pmid36580984, year = {2023}, author = {Xu, L and Yang, Y and Su, J and He, C and Shi, J and Yan, H and Wei, H}, title = {Simultaneous removal of nitrate, lead, and tetracycline by a fixed-biofilm reactor assembled with kapok fiber and sponge iron: Comparative analysis of operating conditions and biotic community.}, journal = {Environmental research}, volume = {219}, number = {}, pages = {115163}, doi = {10.1016/j.envres.2022.115163}, pmid = {36580984}, issn = {1096-0953}, mesh = {*Nitrates ; *Iron ; Lead ; Tetracycline ; Anti-Bacterial Agents ; Biofilms ; Carbon ; Biota ; Bioreactors ; Nitrogen ; }, abstract = {In recent years, under the condition of lack of carbon source, the presence of composite micro-pollutants make the removal of nitrate seriously damaged, and to find a suitable way to solve this problem is imminent. A fixed-biofilm carrier modified by mixing sponge iron (SI) and kapok fiber (KF) combined with strain Zoogloea sp. FY6 was constructed in this study to get a fixed-biofilm reactor with merit denitrification performance. By adjusting the operation parameters, it can be concluded that when the carbon to nitrogen (C/N) ratio was 1.5, the hydraulic retention time (HRT) was 6.0 h, and the pH was 6.0, the nitrate removal efficiency (NRE) of the fixed-biofilm reactor was up to 95.4% (2.95 mg L[-1] h[-1]). In addition, the fixed-biofilm reactor constructed in this study can remove lead (Pb[2+]) and tetracycline (TC) excellently in the presence of SI and Zoogloea sp. FY6, and the denitrification performance can still maintain a high level under the influence of different concentrations of Pb[2+] and TC. Furthermore, the addition of SI not only removes the compound pollutants, but also protects the toxicity of the pollutant inflow in the bioreactor, and the metabolic process of microorganisms in the bioreactor also removes some of the compound pollutants. The high-throughput data showed the abundance of strain Zoogloea sp. FY6 was still the highest value under the influence of various pollutants, and the metagenomic prediction showed that the fixed-biofilm reactor had perfect denitrification process and iron redox cycle benefits. This study provides a valuable reference for sustainable utilization of natural biological resources and reduction of material costs in wastewater treatment plants (WWTPs).}, } @article {pmid36580768, year = {2023}, author = {Ramachandra, SS and Abdal-Hay, A and Han, P and Lee, RSB and Ivanovski, S}, title = {Fabrication and characterization of a 3D polymicrobial microcosm biofilm model using melt electrowritten scaffolds.}, journal = {Biomaterials advances}, volume = {145}, number = {}, pages = {213251}, doi = {10.1016/j.bioadv.2022.213251}, pmid = {36580768}, issn = {2772-9508}, mesh = {Humans ; *Tissue Scaffolds/chemistry ; *Tissue Engineering/methods ; RNA, Ribosomal, 16S ; Polymers ; }, abstract = {The majority of current biofilm models or substrates are two-dimensional (2D) and support biofilm growth in the horizontal plane only. Three-dimensional (3D) substrates may support both horizontal and vertical biofilm growth. This study compared biofilm growth quantity and quality between highly porous 3D micrometric fibrous scaffolds and 2D film substrates fabricated from medical grade polycaprolactone (mPCL). Melt electrowriting (MEW), a high-resolution additive manufacturing technology, was employed to design orderly aligned fine (~12 μm) fibre-based 3D scaffolds, while 2D films were fabricated by a casting method. The 3D scaffolds with a controlled pore size of 100 and 250 μm and thickness of ~0.8 mm and 2D films were incubated in pooled saliva collected from six volunteers for 1, 2, 4, 7 and 10 days at 37 °C to facilitate polymicrobial biofilm formation. Crystal violet assay demonstrated greater biofilm biomass in 3D MEW scaffolds than in 2D films. Biofilm thickness in 3D scaffolds was significantly higher compared to the biofilm thickness in 2D films. Both biovolume and substratum coverage of the biofilms was higher in the 3D scaffolds compared to 2D films. Polymeric bridges, pores, and channels characteristic of biofilms could be demonstrated by scanning electron microscopy. 16S rRNA sequencing demonstrated that the polymicrobial biofilms in the 3D scaffolds were able to retain 60-70 % of the original inoculum microbiome after 4 days. The MEW-fabricated 3D fibrous scaffold is a promising substrate for supporting multidirectional biofilm growth and modelling of a polymicrobial microcosm.}, } @article {pmid36580163, year = {2022}, author = {Ma, N and Guo, P and Chen, J and Qi, Z and Liu, C and Shen, J and Sun, Y and Chen, X and Chen, GQ and Ma, X}, title = {Poly-β-hydroxybutyrate alleviated diarrhea and colitis via Lactobacillus johnsonii biofilm-mediated maturation of sulfomucin.}, journal = {Science China. Life sciences}, volume = {}, number = {}, pages = {}, pmid = {36580163}, issn = {1869-1889}, abstract = {Maintainance of sulfomucin is a key end point in the treatment of diarrhea and inflammatory bowel disease (IBD). However, the mechanisms underlying the microbial sense to sulfomucin are poorly understood, and to date, there are no therapies targeting the secretion and maturation of sulfomucin in IBD. Herein, we biosynthesized poly-β-hydroxybutyrate (PHB) and found that PHB could alleviate inflammation caused by diarrhea and colitis by enhancing the differentiation of sulfomucin. Microbiota transplantation and clearance together demonstrate that PHB promoting sulfomucin is mediated by Lactobacillus johnsonii (L. johnsonii). Further studies revealed that PHB provides a favorable niche for L. johnsonii biofilm formation to resist disturbance and support its growth. L. johnsonii-biofilm alleviates colitis by regulating fucose residues to promote goblet cell differentiation and subsequent sulfomucin maturation. Importantly, PHB alleviates colitis by enhancing sulfomucin secretion and maturation in a L. johnsonii-dependent manner. PHB represents a class of guardians, acting as a safe probiotic-biofilm delivery system that significantly promotes probiotic proliferation. Altogether, this study adds weight to the possible role of probiotics and functional materials in the treatment of intestinal inflammation. The application of PHB and biofilm self-coating L. johnsonii carries high translational potential and may be of clinical relevance.}, } @article {pmid36579869, year = {2022}, author = {Han, W and Zhou, J and Sheng, D and Wu, D and Zhou, H and Yang, Z and Yin, J and Xia, C and Kan, Y and He, J}, title = {Integration of a pure moving bed biofilm reactor process into a large micro-polluted water treatment plant.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {12}, pages = {3051-3066}, doi = {10.2166/wst.2022.380}, pmid = {36579869}, issn = {0273-1223}, mesh = {*Biofilms ; Bioreactors/microbiology ; Ammonia/chemistry ; Nitrification ; Bacteria ; *Water Purification ; }, abstract = {The pure-MBBR process was applied to remove ammonia in a full-scale micro-polluted-water treatment plant with a daily treatment capacity of 260 × 10[4] m[3]/d, Guangdong, China. The relationship between treatment efficiency, physical and chemical properties and microbial diversity in the process of biofilm growth was explored, and the oxygen transfer model of biofilm was established. The results show that the effluent of two-stage pure MBBR process is stable and up to standard after 10 days' incubation. The nitrification loads of two-stage biofilm was stable on the 14th day. The biomass and biofilm thickness lagged behind the nitrification load, and reached a relatively stable level on the 28th day. The species richness of biofilm basically reached a stable level on the 21st day, and the microbial diversity of primary biofilm was higher. In the primary and secondary stage at different periods, the relative abundance of dominant nitrifying bacteria Nitrospira reaches 8.48-13.60%, 6.48-9.27%, and Nitrosomonas reaches 2.89-5.64%, 0.00-3.48%. The pure MBBR system mainly adopts perforated aeration. Through the cutting and blocking of bubbles by suspended carriers, the oxygen transfer rate of the system was greatly improved.}, } @article {pmid36579711, year = {2023}, author = {Terrettaz, C and Cabete, B and Geiser, J and Valentini, M and Gonzalez, D}, title = {KaiC-like proteins contribute to stress resistance and biofilm formation in environmental Pseudomonas species.}, journal = {Environmental microbiology}, volume = {25}, number = {4}, pages = {894-913}, doi = {10.1111/1462-2920.16330}, pmid = {36579711}, issn = {1462-2920}, mesh = {*Bacterial Proteins/metabolism ; Histidine Kinase/genetics/metabolism ; Circadian Rhythm Signaling Peptides and Proteins/metabolism ; Circadian Rhythm/physiology ; *Cyanobacteria/metabolism ; Phosphorylation ; Pseudomonas/genetics/metabolism ; }, abstract = {KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologues of this protein are widespread among nonphotosynthetic bacteria, but the function, interaction network, and mechanism of action of these proteins are still largely unknown. Here, we focus on KaiC homologues found in environmental Pseudomonas species. Using bioinformatics, we describe the distribution of this protein family in the genus and reveal a conserved interaction network comprising a histidine kinase and response regulator. We characterize experimentally the only KaiC homologue present in Pseudomonas putida KT2440 and Pseudomonas protegens CHA0. Through phenotypic assays and transcriptomics, we show that KaiC is involved in osmotic and oxidative stress resistance in P. putida and in biofilm production in both species. KaiC homologues are found in different phosphorylation states and physically interact with a cognate histidine kinase and response regulator. In contrast with cyanobacterial counterparts, the expression and phosphorylation of KaiC homologues do not correlate with light variations under 12:12 light: dark cycles in either Pseudomonas species, and KaiC itself is not required to support a light-driven behaviour in P. putida. Overall, this suggests that KaiC homologues in Pseudomonas species are involved in environmental stress resistance but not in responses to diurnal rhythms.}, } @article {pmid36577889, year = {2023}, author = {Öztürk, FY and Darcan, C and Kariptaş, E}, title = {The Determination, Monitoring, Molecular Mechanisms and Formation of Biofilm in E. coli.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {54}, number = {1}, pages = {259-277}, pmid = {36577889}, issn = {1678-4405}, mesh = {*Escherichia coli/genetics ; *Biofilms ; Quorum Sensing ; Bacteria ; }, abstract = {Biofilms are cell assemblies embedded in an exopolysaccharide matrix formed by microorganisms of a single or many different species. This matrix in which they are embedded protects the bacteria from external influences and antimicrobial effects. The biofilm structure that microorganisms form to protect themselves from harsh environmental conditions and survive is found in nature in many different environments. These environments where biofilm formation occurs have in common that they are in contact with fluids. The gene expression of bacteria in complex biofilm differs from that of bacteria in the planktonic state. The differences in biofilm cell expression are one of the effects of community life. Means of quorum sensing, bacteria can act in coordination with each other. At the same time, while biofilm formation provides many benefits to bacteria, it has positive and negative effects in many different areas. Depending on where they occur, biofilms can cause serious health problems, contamination risks, corrosion, and heat and efficiency losses. However, they can also be used in water treatment plants, bioremediation, and energy production with microbial fuel cells. In this review, the basic steps of biofilm formation and biofilm regulation in the model organism Escherichia coli were discussed. Finally, the methods by which biofilm formation can be detected and monitored were briefly discussed.}, } @article {pmid36576655, year = {2022}, author = {Maity, S and Sarkar, D and Poddar, K and Patil, P and Sarkar, A}, title = {Biofilm-Mediated Heavy Metal Removal from Aqueous System by Multi-Metal-Resistant Bacterial Strain Bacillus sp. GH-s29.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {36576655}, issn = {1559-0291}, support = {DST/TM/WTI/2K16/264//Department of Science and Technology, Ministry of Science and Technology/ ; }, abstract = {Worldwide ever-augmenting urbanization, modernization, and industrialization have contributed to the release of pernicious compounds and a variety of pollutants into the environment. The pollutants discharged due to industrialization are of global concern. Industrial waste and effluent are comprised of hazardous organic and inorganic chemicals including heavy metals which pose a significant threat to the environment and may bring about numerous diseases or abnormalities in human beings. This brings on greater urgency for remediation of these polluted soil and water using sustainable approaches and mechanisms. In the present research, a multi-metal-resistant, gram-positive, non-virulent bacterial strain Bacillus sp. GH-s29 was isolated from contaminated groundwater of Bhojpur district, Bihar, India. The strain had the potential to develop a biofilm that was able to remediate different heavy metals [arsenic, cadmium, and chromium] from individual and multi-heavy metal solutions. Maximum removal for As (V), Cd (II), and Cr (VI) from individual-metal and the multi-metal solution was observed to be 73.65%, 57.37%, 61.62%, and 48.92%, 28.7%, and 35.46%, respectively. SEM-EDX analysis revealed the sequestration of multi-heavy metals by bacterial biofilm. Further characterization by FTIR analysis ensured that the presence of negatively charged functional groups on the biofilm-EPS such as hydroxyl, phosphate, sulfate, and carboxyl helps in binding to the positively charged metal ions. Thus, Bacillus sp. GH-s29 proved to be an effective and economical alternative for different heavy metal remediation from contaminated sites.}, } @article {pmid36576565, year = {2023}, author = {Wuersching, SN and Westphal, D and Stawarczyk, B and Edelhoff, D and Kollmuss, M}, title = {Surface properties and initial bacterial biofilm growth on 3D-printed oral appliances: a comparative in vitro study.}, journal = {Clinical oral investigations}, volume = {27}, number = {6}, pages = {2667-2677}, pmid = {36576565}, issn = {1436-3771}, mesh = {Humans ; *Polymethyl Methacrylate ; Materials Testing ; *Biofilms ; Printing, Three-Dimensional ; Surface Properties ; }, abstract = {OBJECTIVES: To investigate the initial bacterial adhesion on 3D-printed splint materials in relation to their surface properties.

MATERIALS AND METHODS: Specimens of five printable splint resins (SHERAprint-ortho plus UV, NextDent Ortho Rigid, LuxaPrint Ortho Plus, V-Print Splint, KeySplint Soft), one polymethylmethacrylate (PMMA) block for subtractive manufacturing (Astron CLEARsplint Disc), two conventional powder/liquid PMMA materials (FuturaGen, Astron CLEARsplint), and one polyethylene terephthalate glycol (PETG) thermoplastic sheet for vacuum forming (Erkodur Thermoforming Foil) were produced and finished. Surface roughness Ra was determined via contact profilometry. Surface morphology was examined under a scanning electron microscope. Multi-species bacterial biofilms were grown on entire splints. Total biofilm mass and viable bacterial counts (CFU/ml) within the biofilms were determined. Statistical analyses were performed with a one-way ANOVA, Tukey's post hoc test, and Pearson's test (p < 0.05).

RESULTS: Astron CLEARsplint and KeySplint Soft specimens showed the highest surface roughness. The mean total biofilm mass on KeySplint Soft splints was higher compared to all other materials (p < 0.05). Colony-forming unit per milliliter on FuturaGen, Astron CLEARsplint, and KeySplint Soft splints was one log scale higher compared to all other materials. The other four printable resins displayed overall lower Ra, biofilm mass, and CFU/ml. A positive correlation was found between Ra and CFU/ml (r = 0.69, p = 0.04).

CONCLUSIONS: The 3D-printed splints showed overall favorable results regarding surface roughness and bacterial adhesion. Thermoplastic materials seem to display a higher surface roughness, making them more susceptible to microbial adhesion.

CLINICAL RELEVANCE: The development of caries and gingivitis in patients with oral appliances may be affected by the type of material.}, } @article {pmid36575632, year = {2023}, author = {Pouget, C and Pantel, A and Dunyach-Remy, C and Magnan, C and Sotto, A and Lavigne, JP}, title = {Antimicrobial activity of antibiotics on biofilm formed by Staphylococcus aureus and Pseudomonas aeruginosa in an open microfluidic model mimicking the diabetic foot environment.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {78}, number = {2}, pages = {540-545}, doi = {10.1093/jac/dkac438}, pmid = {36575632}, issn = {1460-2091}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; Staphylococcus aureus ; Pseudomonas aeruginosa ; *Diabetic Foot/microbiology ; *Daptomycin ; Ceftazidime ; Microfluidics ; *Staphylococcal Infections/microbiology ; Biofilms ; *Diabetes Mellitus ; }, abstract = {BACKGROUND: Diabetic foot infections (DFIs) represent a public health problem because of their frequency and the severity of their consequences, i.e. amputation and mortality. Polymicrobial biofilms on the skin surface of these ulcers complicate wound healing. Few in vitro models exist to study the antibiotics activity in this context.

OBJECTIVES: This study evaluated the in vitro activity of antibiotics against the two main bacteria isolated in DFI, Staphylococcus aureus and Pseudomonas aeruginosa, using a dynamic system (BioFlux™ 200) and a chronic wound-like medium (CWM) that mimic the foot ulcer environment.

METHODS: Reference strains and two pairs of clinical S. aureus and P. aeruginosa isolated together from a DFI were cultivated in brain heart infusion and CWM media during 72 h at 37°C, alone and combined in the BioFlux™ 200 system. Antibiotic activity was evaluated after a mechanical debridement. The activities were measured by the reduction of biofilm percentage of bacteria in the microfluidic system using microscopy.

RESULTS: Daptomycin for S. aureus and ceftazidime for P. aeruginosa showed excellent activity to reduce biofilm biomass, whereas linezolid action was more mitigated and dalbavancin was ineffective. Ceftazidime + daptomycin presented the most potent in vitro activity on a mixed biofilm.

CONCLUSIONS: The combination of CWM and the BioFlux™ microfluidic system represents a valuable tool to screen the potential antimicrobial activity of antibiotics under conditions mimicking those encountered in DFI. It could help clinicians in their management of chronic wounds.}, } @article {pmid36575298, year = {2022}, author = {Maldiney, T and Pineau, V and Neuwirth, C and Ouzen, L and Eberl, I and Jeudy, G and Dalac, S and Piroth, L and Blot, M and Sautour, M and Dalle, F and Abdulmalak, C and Ter Schiphorst, R and Pugliesi, PS and Poussant, T and Ogier-Desserrey, A and Fournel, I and de Giraud d'Agay, M and Jacquier, M and Labruyère, M and Aptel, F and Roudaut, JB and Vieille, T and Andreu, P and Prin, S and Charles, PE and Hamet, M and Quenot, JP}, title = {Endotracheal tube biofilm in critically ill patients during the COVID-19 pandemic : description of an underestimated microbiological compartment.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {22389}, pmid = {36575298}, issn = {2045-2322}, mesh = {Humans ; Critical Illness ; Pandemics ; *COVID-19/epidemiology ; Intubation, Intratracheal/methods ; *Pneumonia, Ventilator-Associated/epidemiology ; Biofilms ; Enterobacter ; }, abstract = {Biofilm (BF) growth is believed to play a major role in the development of ventilator-associated pneumonia (VAP) in the intensive care unit. Despite concerted efforts to understand the potential implication of endotracheal tube (ETT)-BF dispersal, clinically relevant data are lacking to better characterize the impact of its mesostructure and microbiological singularity on the occurrence of VAP. We conducted a multicenter, retrospective observational study during the third wave of the COVID-19 pandemic, between March and May 2021. In total, 64 ETTs collected from 61 patients were included in the present BIOPAVIR study. Confocal microscopy acquisitions revealed two main morphological aspects of ETT-deposited BF: (1) a thin, continuous ribbon-shaped aspect, less likely monobacterial and predominantly associated with Enterobacter spp., Streptococcus pneumoniae or Viridans streptococci, and (2) a thicker, discontinuous, mushroom-shaped appearance, more likely characterized by the association of bacterial and fungal species in respiratory samples. The microbiological characterization of ETT-deposited BF found higher acquired resistance in more than 80% of analyzed BF phenotypes, compared to other colonization sites from the patient's environment. These findings reveal BF as a singular microbiological compartment, and are of added clinical value, with a view to future ETT-deposited BF-based antimicrobial stewardship in critically ill patients. Trial registration NCT04926493. Retrospectively registered 15 June 2021.}, } @article {pmid36574888, year = {2023}, author = {Liu, Q and Hou, J and Zeng, Y and Xia, J and Miao, L and Wu, J}, title = {Integrated photocatalysis and moving bed biofilm reactor (MBBR) for treating conventional and emerging organic pollutants from synthetic wastewater: Performances and microbial community responses.}, journal = {Bioresource technology}, volume = {370}, number = {}, pages = {128530}, doi = {10.1016/j.biortech.2022.128530}, pmid = {36574888}, issn = {1873-2976}, mesh = {Humans ; Wastewater ; Waste Disposal, Fluid ; *Environmental Pollutants ; Biofilms ; Bioreactors ; *Microbiota ; }, abstract = {Increasing concern for emerging organic pollutants (e.g. antibiotics) urges improvements in conventional biological wastewater treatment processes. This study examined the performance of an integrated photocatalysis and moving bed biofilm reactor (MBBR) system in treating synthetic wastewater containing sulfamethoxazole (SMX). It was found that the integrated system could remove over 80.5 % of SMX and 67.7-80.7 % of chemical oxygen demand (COD) with a hydraulic retention time of 24 h. The introduction of photocatalysis had no impact on COD removal and significantly enhanced SMX removal. High-throughput analysis indicated that microbial community greatly altered due to photocatalytic oxidation stress, with clostridiaceae and enterobacteriaceae becoming dominant families. Nevertheless, microorganisms maintained metabolic activity, which may be ascribed to the protection of carriers and microbial self-preservation by secreting extracellular polymeric substances and antioxidant enzymes. Collectively, this study sheds light on treating wastewater containing conventional and emerging organic pollutants by integrating photocatalysis with MBBR.}, } @article {pmid36573013, year = {2023}, author = {Khoshnood, S and Sadeghifard, N and Mahdian, N and Heidary, M and Mahdian, S and Mohammadi, M and Maleki, A and Haddadi, MH}, title = {Antimicrobial resistance and biofilm formation capacity among Acinetobacter baumannii strains isolated from patients with burns and ventilator-associated pneumonia.}, journal = {Journal of clinical laboratory analysis}, volume = {37}, number = {1}, pages = {e24814}, pmid = {36573013}, issn = {1098-2825}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology ; *Acinetobacter baumannii ; Drug Resistance, Multiple, Bacterial/genetics ; *Pneumonia, Ventilator-Associated/epidemiology ; Drug Resistance, Bacterial/genetics ; Biofilms ; *Burns ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Acinetobacter baumannii is a pathogen responsible for nosocomial infections, especially in patients with burns and ventilator-associated pneumonia (VAP). The aims of this study was to compare the biofilm formation capacity, antimicrobial resistance patterns and molecular typing based on PFGE (Pulsed-Field Gel Electrophoresis) in A. baumannii isolated from burn and VAP patients.

MATERIALS AND METHODS: A total of 50 A. baumannii isolates were obtained from burn and VAP patients. In this study, we assessed antimicrobial susceptibility, biofilm formation capacity, PFGE fingerprinting, and the distribution of biofilm-related genes (csuD, csuE, ptk, ataA, and ompA).

RESULTS: Overall, 74% of the strains were multidrug resistant (MDR), and 26% were extensively drug-resistant (XDR). Regarding biofilm formation capacity, 52%, 36%, and 12% of the isolates were strong, moderate, and weak biofilm producers. Strong biofilm formation capacity significantly correlated with XDR phenotype (12/13, 92.3%). All the isolates harbored at least one biofilm-related gene. The most prevalent gene was csuD (98%), followed by ptk (90%), ataA (88%), ompA (86%), and csuE (86%). Harboring all the biofilm-related genes was significantly associated with XDR phenotype. Finally, PFGE clustering revealed 6 clusters, among which cluster No. 2 showed a significant correlation with strong biofilm formation and XDR phenotype.

CONCLUSION: Our findings revealed the variable distribution of biofilm-related genes among MDR and XDR A. baumannii isolates from burn and VAP patients. A significant correlation was found between strong biofilm formation capacity and XDR phenotype. Finally, our results suggested that XDR phenotype was predominant among strong-biofilm producer A. baumannii in our region.}, } @article {pmid37223347, year = {2022}, author = {Yoshida, M and Thiriet-Rupert, S and Mayer, L and Beloin, C and Ghigo, JM}, title = {Selection for nonspecific adhesion is a driver of FimH evolution increasing Escherichia coli biofilm capacity.}, journal = {microLife}, volume = {3}, number = {}, pages = {uqac001}, pmid = {37223347}, issn = {2633-6693}, abstract = {Bacterial interactions with surfaces rely on the coordinated expression of a vast repertoire of surface-exposed adhesins. However, how bacteria dynamically modulate their adhesion potential to achieve successful surface colonization is not yet well understood. Here, we investigated changes in adhesion capacity of an initially poorly adherent Escherichia coli strain using experimental evolution and positive selection for mutations improving adhesion and biofilm formation on abiotic surfaces. We showed that all identified evolved populations and clones acquired mutations located almost exclusively in the lectin domain of fimH, the gene coding for the α-d-mannose-specific tip adhesin of type 1 fimbriae, a key E. coli virulence factor. While most of these fimH mutants showed reduced mannose-binding ability, they all displayed enhanced binding to abiotic surfaces, indicating a trade-off between FimH-mediated specific and nonspecific adhesion properties. Several of the identified mutations were already reported in the FimH lectin domain of pathogenic and environmental E. coli, suggesting that, beyond pathoadaptation, FimH microevolution favoring nonspecific surface adhesion could constitute a selective advantage for natural E. coli isolates. Consistently, although E. coli deleted for the fim operon still evolves an increased adhesion capacity, mutants selected in the ∆fim background are outcompeted by fimH mutants revealing clonal interference for adhesion. Our study therefore provides insights into the plasticity of E. coli adhesion potential and shows that evolution of type 1 fimbriae is a major driver of the adaptation of natural E. coli to colonization.}, } @article {pmid37334228, year = {2021}, author = {Madden, L and Low, SH and Phillips, ARJ and Kline, KA and Becker, DL}, title = {The effects of Staphylococcus aureus biofilm conditioned media on 3T3 fibroblasts.}, journal = {FEMS microbes}, volume = {2}, number = {}, pages = {xtab010}, pmid = {37334228}, issn = {2633-6685}, abstract = {Staphylococcus aureus (SA) is the most common bacterial species in chronic wounds. However, there is a lack of understanding of how SA secretions affect the cell biology during the healing process. We studied the effects of biofilm-secretions from SA strain SA29213 on 3T3 fibroblasts. SA29213 is a chronic wound isolate and widely used as a reference strain. We used a series of concentrations of biofilm-conditioned media (BCM) and found 100% BCM is lethal within 10 h. Cells survived in ≤75% BCM but the rate of closure in scratch wound assays was reduced. Treatment with 75% and 50% BCM caused fibroblasts to change shape and develop dendrite like processes. Prolonged treatment with 75% and 50% BCM reduced cell proliferation and increased the 4n deoxyribonucleic acid cell population with cell cycle arrest. There was also an elevation in the senescence marker beta galactosidase and the number of multinucleated cells. Shorter treatments with 75% and 50% SA BCM caused an increase in cell-cell adhesion and a redistribution of β-catenin from the cell membrane to the cytoplasm along with a change in the appearance and decrease in size of ZO-1, vinculin and paxillin structures. Fibroblasts in the edge of chronic wounds exposed to the secretions of SA may suffer similar effects such as induction of senescence, reduced proliferation and migration, which may contribute to the delayed healing of these chronic infected wounds.}, } @article {pmid36704397, year = {2021}, author = {Tour Savadkouhi, S and Mohtasham Maram, M and Purhaji Bagher, M and Afkar, M and Fazlyab, M}, title = {In Vitro Activity of Superoxide Water on Viability of Enterococcus faecalis Biofilm on Root Canal Wall.}, journal = {Iranian endodontic journal}, volume = {16}, number = {3}, pages = {189-192}, pmid = {36704397}, issn = {2008-2746}, abstract = {INTRODUCTION: The aim of this study was to compare the effect of root canal irrigation with superoxidized water and sodium hypochlorite on elimination of Enterococcus faecalis biofilm from the root canal walls.

METHODS AND MATERIALS: In this experimental study, a total of 32 extracted human central incisors were used. The crowns of all teeth were cut to length of 16 mm. After cleaning and shaping, then the specimens were sterilized in autoclave and then divided into four groups (n=8) as following: group 1 (positive control, root canal irrigation with normal saline), group 2 (negative control without biofilm), group 3 (root canal irrigation with sodium hypochlorite) and group 4 (root canal irrigation with superoxidized water). The bacterial suspension was inserted to root canals of teeth except for negative control group in order to form a microbial biofilm in incubator for 2 weeks. Then all the samples received root canal irrigation for 5 min based on their allocation. At the end, colony forming unit (CFU) was evaluated and biofilm formation and thickness was detected with scanning electron microscopy. The Kruskal Wallis and Dunn's tests were done for biofilm thickness and CFU, respectively with the level of significance set at 0.05.

RESULTS: In negative control group no biofilm formation and CFU was present. The CFU counts and biofilm thickness were significantly different between the experimental groups (P=0.001) and both parameters were less in samples with hypochlorite irrigation compared to positive control (52.56±5.82 µm for biofilm thickness and 1.2×10[7] CFU) and samples irrigated with superoxidized water (2.92±1.76 µm for biofilm thickness and 5.4×10[4] CFU).

CONCLUSION: Based on this in vitro study reduction in biofilm thickness and CFU/mL was 100% for sodium hypochlorite and for superoxidized water was 98% and 90% for reduction in biofilm thickness and CFU/mL, respectively.}, } @article {pmid36703803, year = {2020}, author = {Byakova, SF and Dezhurko-Korol, VA and Novozhilova, NE and Makeeva, IM and Lukashev, AN and Akhmadishina, LV and Semenov, AM and Moisenovich, MM and Arkhipova, AY and Ponirovsky, EN}, title = {Quantitative Assessment of Dentinal Tubule Disinfection in Absence of Biofilm on Root Canal Walls: An in vitro Study.}, journal = {Iranian endodontic journal}, volume = {15}, number = {3}, pages = {155-165}, pmid = {36703803}, issn = {2008-2746}, abstract = {INTRODUCTION: This study aimed at assessing the quantitative effect of calcium hydroxide, 2% chlorhexidine gel, and 1.5% chlorhexidine linked to xanthan gel specifically against intratubular bacteria.

METHODS AND MATERIALS: Fifty-two semi-cylindrical bovine dentin specimens were infected with Enterococcus (E.) faecalis by centrifugation with subsequent 7-days incubation. The surface of specimens was disinfected with 3% H2O2. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and the count of bacterial colony-forming units (CFU/mg) were used to assess dentin infection. A total of 40 specimens were incubated for 2 weeks with one of the intracanal medication applied (10 samples for each group): 1) calcium hydroxide, 2) 2% chlorhexidine gel, 3) 1.5% chlorhexidine linked to xanthan gel and 4) sterile saline. Final passive ultrasonic irrigation with 3% sodium hypochlorite was performed in half of the total specimens. The effect of intracanal medications and irrigation against intratubular bacteria was assessed by bacterial culturing of dentin shavings. Two-Way ANOVA model was applied followed by post-hoc Tukey's test for multiple pair-wise comparisons of mean CFU/mg values.

RESULTS: SEM, CLSM, and bacterial culturing confirmed the absence of the surface biofilm on the root canal wall and showed vital intratubular bacteria at the depth up to 700  m. Two-week application of 1.5% chlorhexidine with xanthan gel and 2% chlorhexidine gel significantly decreased intratubular bacterial counts compared with saline (P=0.0003 and P=0.0005, respectively). Subsequent passive ultrasonic irrigation with 3% sodium hypochlorite significantly reduced the number of intratubular bacteria in all groups except for the group with 1.5% chlorhexidine-xanthan gel (P=0.0054).

CONCLUSION: This modified ex vivo model study showed ultrasonically activated irrigation with sodium hypochlorite had greater effect on intratubular bacteria counts compared with 2-week application of intracanal medications.}, } @article {pmid36814951, year = {2019}, author = {Shadmehr, E and Davoudi, A and Damoon Sarmast, N and Saatchi, M}, title = {Evaluation of Antimicrobial Effcacy of Calcium Hypochlorite as an Endodontic Irrigant on a Mixed-Culture Biofilm: An Ex vivo Study.}, journal = {Iranian endodontic journal}, volume = {14}, number = {3}, pages = {178-184}, pmid = {36814951}, issn = {2008-2746}, abstract = {INTRODUCTION: Calcium hypochlorite (CH) has been recently suggested as an endodontic irrigant. The aim of this investigation was to evaluate the antimicrobial efficacy of CH compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX) against multispecies biofilm in surface and deep dentinal tubules.

METHODS AND MATERIALS: Minimal inhibitory concentration (MIC) of irrigant agents was assessed using a microdilution method. One hundred and twenty of human maxillary incisor teeth were prepared and infected with suspension of Entrococcus faecalis, Fusobacterium nucleatum and Prevotella intermedia in an anaerobic jar for 7 days. Depending on irrigation solutions, specimens were divided into 4 groups (n=30); group 1: 2% CHX, group 2: 5.25% sodium hypochlorite, group 3: 5% calcium hypochlorite, group 4: positive control (normal saline (NS)). Fifteen remained specimens were used as negative control. Surviving bacteria were sampled before (S1) and after irrigation from surface (S2) and deep (S3) dentin. The medium turbidity was visualized with spectrophotometry. Data were analyzed using analysis of variance followed by Tukey post hoc test (α=0.05).

RESULTS: The MIC of CH against E. faecalis, F. nucleatum and P. intermedia was 25, 8 and 7.5 µg/mL respectively. There were no significant differences in S1 among the test groups. Moreover, 2% CHX and 5% CH had significantly lower medium turbidity at both S2 and S3, in comparison with 5.25% NaOCl (P=0.018 and 0.031, respectively). But there were no significant differences between 2% CHX and 5% CH at both S2 and S3 (P=0.862 and 0.978, respectively).

CONCLUSION: Under the conditions of this ex vivo study, 5% CH and 2% CHX are more effective than 5.25% NaOCl in the reduction of mixed-culture biofilm.}, } @article {pmid36879587, year = {2019}, author = {Rastegar Khosravi, M and Khonsha, M and Ramazanzadeh, R}, title = {Combined Effect of Levofloxacin and N-Acetylcysteine against Enterococcus faecalis Biofilm for Regenerative Endodontics: An in Vitro Study.}, journal = {Iranian endodontic journal}, volume = {14}, number = {1}, pages = {40-46}, pmid = {36879587}, issn = {2008-2746}, abstract = {INTRODUCTION: Endodontic treatment of necrotic immature teeth poses several clinical challenges. A major problem is the elimination of microorganisms from the root canal system. This study evaluates the in vitro antibacterial efficacy of ciprofloxacin (CIP), levofloxacin (LEV), and their combination with N-acetylcysteine (NAC) in root canals infected with Enterococcus faecalis (E. faecalis).

METHODS AND MATERIALS: A total of 120 human extracted teeth with single canals were prepared and randomly divided into six groups: Calcium hydroxide (CH), ciprofloxacin (CIP), levofloxacin (LEV), ciprofloxacin and N-acetylcysteine (CIP+NAC), levofloxacin and N-acetylcysteine (LEV+NAC), and normal saline as a positive control. According to the name of the groups, intracanal medicaments were placed into the canals and the teeth were restored with a temporary filling. After one week, intracanal medicament was removed and the final count of bacteria was measured. Antibacterial effect of medicament was assessed by measuring the percentage reduction in the colony counts (RCC) and scanning electron microscopy (SEM). The Mann-Whitney U test and the Kruskal-Wallis test were used to compare the overall antibacterial efficacy of the intracanal medicaments at significance level of 0.05.

RESULTS: All intracanal medicaments were significantly more effective than calcium hydroxide (P<0.05). The combination of LEV and NAC caused significantly higher reduction in colony count in comparison with other tested medicaments (P=0.001).

CONCLUSION: The combination of LEV and NAC showed greater antibacterial activity compared with other tested medicaments against biofilm of E. faecalis. Thus, it has the potential to be used in regenerative endodontic treatments.}, } @article {pmid36883019, year = {2018}, author = {Ghahramani, Y and Yaghoobi, F and Motamedi, R and Jamshidzadeh, A and Abbaszadegan, A}, title = {Effect of Endodontic Irrigants and Medicaments Mixed with Silver Nanoparticles against Biofilm Formation of Enterococcus faecalis.}, journal = {Iranian endodontic journal}, volume = {13}, number = {4}, pages = {559-564}, pmid = {36883019}, issn = {2008-2746}, abstract = {INTRODUCTION: The aim of this study was to evaluate the effectiveness of chlorhexidine (CHX), sodium hypochlorite (NaOCl), calcium hydroxide (CH) and double antibiotic paste (DAP) mixed with silver nanoparticles (AgNPs) against Enterococcus faecalis .

METHODS AND MATERIALS: Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and biofilm formation inhibition (after 72 h) of the experimental substances alone or mixed with AgNPs were measured against E. faecalis using microtiter plate method. Bacterial cultures turbidity was measured using a spectrophotometer. All procedures were performed in triplicates.

RESULTS: The MIC values for CHX, NaOCl, CH and DAP were equal to 0.012, 1.25, 1.6 and 0.156 mg/mL, and their MBC's were 0.025, 2.5, 0 and 0.625 mg/mL. After mixing them with AgNPs, the MIC's for CHX, NaOCl, CH and DAP were reduced to 0.0032, 0.158, 0.2 and 0.0391 mg/mL, while their MBC's were reduced to 0.0064, 0.0632, 0.401 and 0.0156 mg/mL. Biofilm formation inhibition occurred in higher dilutions of all irrigants and medicaments as they were mixed with Ag NPs.

CONCLUSIONS: Adding AgNPs resulted in an increased antimicrobial activity at the tested dilutions for all experimental substances. More investigations in in vivo conditions are required to confirm the results of this study.}, } @article {pmid36572871, year = {2022}, author = {Tashakkori, N and Rahmani, HK and Khoramian, B}, title = {Genotypic and phenotypic diversity of Prototheca spp. recovered from bovine mastitis in terms of antimicrobial resistance and biofilm formation ability.}, journal = {BMC veterinary research}, volume = {18}, number = {1}, pages = {452}, pmid = {36572871}, issn = {1746-6148}, support = {Ferdowsi University of Mashhad//Ferdowsi University of Mashhad/ ; }, mesh = {Cattle ; Female ; Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Prototheca/genetics ; Random Amplified Polymorphic DNA Technique/veterinary ; *Mastitis, Bovine/drug therapy/microbiology ; Colistin/pharmacology ; Drug Resistance, Bacterial/genetics ; *Anti-Infective Agents/pharmacology/therapeutic use ; Biofilms ; Gentamicins/pharmacology ; *Cattle Diseases ; }, abstract = {BACKGROUND: The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Isolates from bovine mastitis in several countries were nearly all identified as P. bovis, suggesting that it was the main causative agent of bovine protothecal mastitis. The aim of the present study was to evaluate the presence and isolation of Prototheca spp. in dairy farms, detect the genetic diversity among strains, determine the capacity of producing biofilm and their resistance to antifungal and antimicrobial drugs.

RESULTS: A total of 48 Prototheca isolates from four different farms were randomly selected to be investigated. Multiplex PCR showed all isolated colonies were Prototheca bovis. Performing RAPD-PCR by using OPA-4 primer, it was revealed that there was a clear amplification pattern. Different levels of biofilm production were observed among strains. Among 48 isolates, only 4 of them (8.33%) showed strong biofilm production. By using E-test strips, amphotericin B was able to inhibit the growth of all the strains tested. Disc diffusion method used for antimicrobial sensitivity test showed that the highest activity was demonstrated by gentamicin and colistin with 95.83% (46/48) and 89.58% (43/48) of sensitive strains, respectively.

CONCLUSIONS: The present study showed that RAPD-PCR was a rapid tool for discriminating P. bovis strains. Also, gentamicin and colistin can be considered as potential antimicrobial drugs which can prevent the growth of the mentioned strains in vitro, although there is no effective clinical treatment yet. Further studies are needed in order to detect an effective clinical therapy considering biofilm production by Prototheca spp. and their probable role in Prototheca pathogenicity.}, } @article {pmid36570317, year = {2022}, author = {Sahoo, J and Sarkhel, S and Mukherjee, N and Jaiswal, A}, title = {Nanomaterial-Based Antimicrobial Coating for Biomedical Implants: New Age Solution for Biofilm-Associated Infections.}, journal = {ACS omega}, volume = {7}, number = {50}, pages = {45962-45980}, pmid = {36570317}, issn = {2470-1343}, abstract = {Recently, the upsurge in hospital-acquired diseases has put global health at risk. Biomedical implants being the primary source of contamination, the development of biomedical implants with antimicrobial coatings has attracted the attention of a large group of researchers from around the globe. Bacteria develops biofilms on the surface of implants, making it challenging to eradicate them with the standard approach of administering antibiotics. A further issue of current concern is the fast resurgence of resistance to conventional antibiotics. As nanotechnology continues to advance, various types of nanomaterials have been created, including 2D nanoparticles and metal and metal oxide nanoparticles with antimicrobial properties. Researchers from all over the world are using these materials as a coating agent for biomedical implants to create an antimicrobial environment. This comprehensive and contemporary review summarizes various metals, metal oxide nanoparticles, 2D nanomaterials, and their composites that have been used or may be used in the future as an antimicrobial coating agent for biomedical implants, as well as their succinct mode of action to combat biofilm-associated infection and diseases.}, } @article {pmid36569981, year = {2022}, author = {Vyas, HKN and Xia, B and Mai-Prochnow, A}, title = {Clinically relevant in vitro biofilm models: A need to mimic and recapitulate the host environment.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100069}, pmid = {36569981}, issn = {2590-2075}, abstract = {Biofilm-associated infections are difficult to treat and eradicate because of their increased antimicrobial tolerance. In vitro biofilm models have enabled the high throughput testing of an array of differing novel antimicrobials and treatment strategies. However, biofilms formed in these oftentimes basic in vitro systems do not resemble biofilms seen in vivo. As a result, translatability from the lab to the clinic is poor or limited. To improve translatability, in vitro models must better recapitulate the host environment. This review describes and critically evaluates new and innovative in vitro models that better mimic the environments of a variety of clinically important, biofilm-associated infections of the skin, oropharynx, lungs, and infections related to indwelling implants and medical devices. This review highlights that many of these models represent considerable advances in the field of biofilm research and help to translate laboratory findings into the clinical practice.}, } @article {pmid36567396, year = {2022}, author = {Odame, F and Neglo, D and Sedohia, D and Arthur, R}, title = {Antifungal synergistic effects and anti-biofilm formation activities of some bioactive 2,3-dihydro-1,5-benzoxazepine derivatives.}, journal = {Archives of microbiology}, volume = {205}, number = {1}, pages = {39}, pmid = {36567396}, issn = {1432-072X}, mesh = {Humans ; Female ; Antifungal Agents/pharmacology ; Antioxidants/pharmacology ; Fluconazole/pharmacology ; *Candidiasis, Vulvovaginal/microbiology ; *Fungicides, Industrial/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; Candida albicans ; }, abstract = {Benzoxazepines constitute a significant class of organic compounds extensively described in the literature. Several derivatives with pharmacological properties have been produced due to the semi-rigid azepine scaffold, which allows for the addition of other heteroatoms. This study investigated the possible antifungal effect and antioxidant activity of 2,3-dihydro-1,5-benzoxazepines. The antifungal effect was investigated using the broth dilution assay, while the antioxidant property was determined using the ABTS and DPPH scavenging tests. The results indicated that the 2,3-dihydro-1,5-benzoxazepine derivatives had antifungal properties and could be working via its fungicidal and biofilm inhibitory properties. It was also realized that it had synergistic effects when administered concomitantly with standard antifungal drugs. The antioxidant effects were high with 2,2-dimethyl-4-[(E)-2-(4-methylphenyl)ethenyl]-2,3-dihydro-1,5-benzoxazepine (1) compared to the other derivatives. It could be concluded that 2,3-dihydro-1,5-benzoxazepines could possess fungicidal and possible antioxidant properties. And hence could serve as new drug leads in discovering novel drugs that could help manage fluconazole-resistant vulvovaginal candidiasis.}, } @article {pmid36567138, year = {2022}, author = {Malone, M and Radzieta, M and Schwarzer, S and Walker, A and Bradley, J and Jensen, SO}, title = {In vivo observations of biofilm adhering to a dialkylcarbamoyl chloride-coated mesh dressing when applied to diabetes-related foot ulcers: A proof of concept study.}, journal = {International wound journal}, volume = {}, number = {}, pages = {}, doi = {10.1111/iwj.14054}, pmid = {36567138}, issn = {1742-481X}, support = {//Essity Germany/ ; }, abstract = {In this proof-of-concept study of twenty participants, we sought to determine if a DACC (Dialkylcarbamoyl chloride)-coated mesh dressing demonstrates an ability to adhere biofilm when placed on Diabetes Related Foot Ulcers (DRFUs) with chronic infection. The study also sought to determine if removal of the DACC-coated mesh dressings contributes to reducing the total number of bacteria in DRFUs, by exploring the total microbial loads, microbial community composition, and diversity. Standard of care was provided in addition to the application of DACC or DACC hydrogel every three days for a total of two weeks. Wound swabs, tissue curettage, and soiled dressings were collected pre and post-treatment. Tissue specimens obtained pre-treatment were analysed with scanning electron microscopy (SEM) and peptide nucleic acid fluorescent in situ hybridisation (PNA-FISH) with confocal laser scanning microscopy and confirmed the presence of biofilm in all DRFUs. SEM confirmed the presence of biofilms readily adhered to soiled DACC-coated mesh dressings pre- and post-treatment in all participants. Real-time quantitative polymerase chain reaction (qPCR) demonstrated the mean total microbial load of DRFUs in 20 participants did not change after two weeks of therapy (pre-treatment = 4.31 Log10 16 S copies (±0.8) versus end of treatment = 4.32 Log10 16 S copies (±0.9), P = .96, 95% CI -0.56 to 0.5). 16 S sequencing has shown the microbial composition of DACC dressings and wound swabs pre- and post-treatment remained similar (DACC; R = -.047, P = .98, Swab; R = -.04, P = .86), indicating the microbial communities originate from the ulcer. Biofilms adhere to DACC-coated mesh dressings; however, this may not reduce the total microbial load present within DRFU tissue. Wound dressings for use in hard-to-heal wounds should be used as an adjunct to a good standard of care which includes debridement and wound bed preparation.}, } @article {pmid36566688, year = {2023}, author = {Razdan, K and Kanta, S and Chaudhary, E and Kumari, S and Rahi, DK and Yadav, AK and Sinha, VR}, title = {Levofloxacin loaded clove oil nanoscale emulgel promotes wound healing in Pseudomonas aeruginosa biofilm infected burn wound in mice.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {222}, number = {}, pages = {113113}, doi = {10.1016/j.colsurfb.2022.113113}, pmid = {36566688}, issn = {1873-4367}, mesh = {Mice ; Animals ; Levofloxacin/pharmacology ; Pseudomonas aeruginosa ; Clove Oil/pharmacology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Wound Infection/drug therapy/metabolism/microbiology ; *Burns/drug therapy/microbiology ; Wound Healing ; *Pseudomonas Infections/drug therapy ; }, abstract = {Owing to their tolerance to antibiotics, bacterial biofilms continue to pose a threat to mankind and are leading cause for non-healing of burn wounds. Within the biofilm matrix, antibiotics become functionally inactive due to restricted penetration and enzymatic degradation leading to rise of antimicrobial resistance. The objective of present investigation was to develop and characterize levofloxacin (LFX) loaded clove oil nanoscale emulgel (LFX-NE gel) and evaluate its in vivo therapeutic efficacy in Pseudomonas aeruginosa biofilm infected burn wound in mice. The optimized emulgel was found to possess good texture profile and showed shear thinning behavior. In vitro release study demonstrated complete drug release in 8 h and emulgel was found to be stable for 3 months at 25 °C and 40 °C. In vivo study revealed biofilm dispersal, complete wound closure, re-epithelialization and collagen deposition by LFX-NE gel in comparison to various control groups. LFX-NE gel was able to clear the infection within 7 days of treatment and promote wound healing as well. Therefore, administration of LFX-incorporated NE gel could be a beneficial treatment strategy for P. aeruginosa biofilm-infected burn wounds.}, } @article {pmid36565767, year = {2023}, author = {Ramos, P and Honda, R and Hoek, EMV and Mahendra, S}, title = {Carbon/nitrogen ratios determine biofilm formation and characteristics in model microbial cultures.}, journal = {Chemosphere}, volume = {313}, number = {}, pages = {137628}, doi = {10.1016/j.chemosphere.2022.137628}, pmid = {36565767}, issn = {1879-1298}, mesh = {*Carbon/metabolism ; *Nitrogen/pharmacology ; Biofilms ; Quorum Sensing ; Carbohydrates ; Pseudomonas aeruginosa ; }, abstract = {The influence of growth medium water chemistry, specifically carbon/nitrogen (C/N) molar ratios, on the characteristics and development of biofilms of the model microorganism Pseudomonas aeruginosa was investigated. C/N = 9 had a unique effect on biofilm composition as well as quorum sensing (QS) pathways, with higher concentrations of carbohydrates and proteins in the biofilm and a significant upregulation of the QS gene lasI in planktonic cells. The effect of C/N ratio on total attached biomass was negligible. Principal component analysis revealed a different behavior of most outputs such as carbohydrates and QS chemicals at C/N = 9, and pointed to correlations between parameters of biofilm formation and steady state distribution of cells and extracellular components. C/N ratio was also shown to influence organic compound utilization by both planktonic and sessile organisms, with a maximum chemical oxygen demand (COD) removal of 83% achieved by biofilms at C/N = 21. Planktonic cells achieved higher COD removal rates, but greater overall rates after six days occurred in biofilms. The development of a dual-species biofilm of P. aeruginosa and Nitrobacter winogradskyi was also influenced by C/N, with increase in the relative abundance of the slower-growing N. winogradskyi above C/N = 9. These results indicate that altering operational parameters related to C/N would be relevant for mitigating or promoting biofilm formation and function depending on the desired industrial application or treatment configuration.}, } @article {pmid36565384, year = {2022}, author = {Chatterjee, S and Das, S}, title = {Whole-genome sequencing of biofilm-forming and chromium-resistant mangrove fungus Aspergillus niger BSC-1.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {2}, pages = {55}, pmid = {36565384}, issn = {1573-0972}, support = {BT/PR9465/NDB/39/360/2013//Department of Biotechnology, Ministry of Science and Technology, India/ ; BT/PR9465/NDB/39/360/2013//Department of Biotechnology, Ministry of Science and Technology, India/ ; }, mesh = {*Aspergillus niger/genetics/metabolism ; *Chromium/metabolism ; Ecosystem ; Biofilms ; }, abstract = {Filamentous fungus Aspergillus niger has gained significant industrial and ecological value due to its great potential in enzymatic activities. The present study reports the complete genome sequence of A. niger BSC-1 which was isolated from Indian Sundarban mangrove ecosystem. The study revealed that the genome of A. niger BSC-1 was 35.1 Mbp assembled in 40 scaffolds with 49.2% GC content. A total of 10,709 genes were reported out of which 10,535 genes were predicted for encoding the proteins. BUSCO assessment showed 98.6% of genome completeness indicating high quality genome sequencing. The genome sequencing of A. niger BSC-1 revealed the presence of rodA and exgA genes for initial adhesion to surface and Ags genes for matrix formation, during biofilm growth. OrthoVenn2 analysis revealed that A.niger BSC-1 shared 9552 gene clusters with the reference strain A. niger CBS554.65. Semi-quantitative RT-PCR analysis unveiled the role of Ags1 and P-type ATPase in fungal biofilm formation and chromium (Cr) resistance, respectively. During biofilm growth the expression of Ags1 significantly (P < 0.0001; two-way ANOVA followed by Sidak's multiple comparisons test) increased with respect to planktonic culture revealing the possible involvement of Ags1 in biofilm matrix formation. Expression of P-type ATPase gene was significantly upregulated (P < 0.0001; one-way ANOVA followed by Dunnett's multiple comparisons test) with the increasing chromium concentration in the fungal culture. Besides, several other genes encoding metalloprotease, copper and zinc binding proteins, and NADH-dependent oxidoreductase were also found in the genome of A. niger BSC-1. These proteins are also involved in heavy metal tolerance and nanofabrication indicating that this filamentous fungus A. niger BSC-1 could be potentially utilized for chromium detoxification through biofilm or nanobiremediation.}, } @article {pmid36565346, year = {2022}, author = {De Silva, LADS and Heo, GJ}, title = {Biofilm formation of pathogenic bacteria isolated from aquatic animals.}, journal = {Archives of microbiology}, volume = {205}, number = {1}, pages = {36}, pmid = {36565346}, issn = {1432-072X}, mesh = {Animals ; *Biofilms ; *Edwardsiella tarda ; }, abstract = {Bacterial biofilm formation is one of the dynamic processes, which facilitates bacteria cells to attach to a surface and accumulate as a colony. With the help of biofilm formation, pathogenic bacteria can survive by adapting to their external environment. These bacterial colonies have several resistance properties with a higher survival rate in the environment. Especially, pathogenic bacteria can grow as biofilms and can be protected from antimicrobial compounds and other substances. In aquaculture, biofilm formation by pathogenic bacteria has emerged with an increased infection rate in aquatic animals. Studies show that Vibrio anguillarum, V. parahaemolyticus, V. alginolyticus, V. harveyi, V. campbellii, V. fischeri, Aeromonas hydrophila, A. salmonicida, Yersinia ruckeri, Flavobacterium columnare, F. psychrophilum, Piscirickettsia salmonis, Edwardsiella tarda, E. ictaluri, E. piscicida, Streptococcus parauberis, and S. iniae can survive in the environment by transforming their planktonic form to biofilm form. Therefore, the present review was intended to highlight the principles behind biofilm formation, major biofilm-forming pathogenic bacteria found in aquaculture systems, gene expression of those bacterial biofilms and possible controlling methods. In addition, the possibility of these pathogenic bacteria can be a serious threat to aquaculture systems.}, } @article {pmid36560950, year = {2022}, author = {Mlynek, KD and Bozue, JA}, title = {Why vary what's working? Phase variation and biofilm formation in Francisella tularensis.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1076694}, pmid = {36560950}, issn = {1664-302X}, abstract = {The notoriety of high-consequence human pathogens has increased in recent years and, rightfully, research efforts have focused on understanding host-pathogen interactions. Francisella tularensis has been detected in an impressively broad range of vertebrate hosts as well as numerous arthropod vectors and single-celled organisms. Two clinically important subspecies, F. tularensis subsp. tularensis (Type A) and F. tularensis subsp. holarctica (Type B), are responsible for the majority of tularemia cases in humans. The success of this bacterium in mammalian hosts can be at least partly attributed to a unique LPS molecule that allows the bacterium to avoid detection by the host immune system. Curiously, phase variation of the O-antigen incorporated into LPS has been documented in these subspecies of F. tularensis, and these variants often display some level of attenuation in infection models. While the role of phase variation in F. tularensis biology is unclear, it has been suggested that this phenomenon can aid in environmental survival and persistence. Biofilms have been established as the predominant lifestyle of many bacteria in the environment, though, it was previously thought that Type A and B isolates of F. tularensis typically form poor biofilms. Recent studies question this ideology as it was shown that alteration of the O-antigen allows robust biofilm formation in both Type A and B isolates. This review aims to explore the link between phase variation of the O-antigen, biofilm formation, and environmental persistence with an emphasis on clinically relevant subspecies and how understanding these poorly studied mechanisms could lead to new medical countermeasures to combat tularemia.}, } @article {pmid36559234, year = {2022}, author = {Polizzi, A and Donzella, M and Nicolosi, G and Santonocito, S and Pesce, P and Isola, G}, title = {Drugs for the Quorum Sensing Inhibition of Oral Biofilm: New Frontiers and Insights in the Treatment of Periodontitis.}, journal = {Pharmaceutics}, volume = {14}, number = {12}, pages = {}, pmid = {36559234}, issn = {1999-4923}, abstract = {Chemical molecules are used by microorganisms to communicate with each other. Quorum sensing is the mechanism through which microorganisms regulate their population density and activity with chemical signaling. The inhibition of quorum sensing, called quorum quenching, may disrupt oral biofilm formation, which is the main etiological factor of oral diseases, including periodontitis. Periodontitis is a chronic inflammatory disorder of infectious etiology involving the hard and soft periodontal tissues and which is related to various systemic disorders, including cardiovascular diseases, diabetes and obesity. The employment of adjuvant therapies to traditional scaling and root planing is currently being studied to further reduce the impact of periodontitis. In this sense, using antibiotics and antiseptics involves non-negligible risks, such as antibiotic resistance phenomena and hinders the re-establishment of eubiosis. Different quorum sensing signal molecules have been identified in periodontal pathogenic oral bacteria. In this regard, quorum sensing inhibitors are emerging as some interesting solutions for the management of periodontitis. Therefore, the aim of this review is to summarize the current state of knowledge on the mechanisms of quorum sensing signal molecules produced by oral biofilm and to analyze the potential of quorum sensing inhibitors for the management of periodontitis.}, } @article {pmid36559194, year = {2022}, author = {Rather, IA and Wani, MY and Kamli, MR and Sabir, JSM and Hakeem, KR and Firoz, A and Park, YH and Hor, YY}, title = {Lactiplantibacillus plantarum KAU007 Extract Modulates Critical Virulence Attributes and Biofilm Formation in Sinusitis Causing Streptococcus pyogenes.}, journal = {Pharmaceutics}, volume = {14}, number = {12}, pages = {}, pmid = {36559194}, issn = {1999-4923}, abstract = {Streptococcus pyogenes is one of the most common bacteria causing sinusitis in children and adult patients. Probiotics are known to cause antagonistic effects on S. pyogenes growth and biofilm formation. In the present study, we demonstrated the anti-biofilm and anti-virulence properties of Lactiplantibacillus plantarum KAU007 against S. pyogenes ATCC 8668. The antibacterial potential of L. plantarum KAU007 metabolite extract (LME) purified from the cell-free supernatant of L. plantarum KAU007 was evaluated in terms of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). LME was further analyzed for its anti-biofilm potential using crystal violet assay and microscopic examination. Furthermore, the effect of LME was tested on the important virulence attributes of S. pyogenes, such as secreted protease production, hemolysis, extracellular polymeric substance production, and cell surface hydrophobicity. Additionally, the impact of LME on the expression of genes associated with biofilm formation and virulence attributes was analyzed using qPCR. The results revealed that LME significantly inhibited the growth and survival of S. pyogenes at a low concentration (MIC, 9.76 µg/mL; MBC, 39.06 µg/mL). Furthermore, LME inhibited biofilm formation and mitigated the production of extracellular polymeric substance at a concentration of 4.88 μg/mL in S. pyogenes. The results obtained from qPCR and biochemical assays advocated that LME suppresses the expression of various critical virulence-associated genes, which correspondingly affect various pathogenicity markers and were responsible for the impairment of virulence and biofilm formation in S. pyogenes. The non-hemolytic nature of LME and its anti-biofilm and anti-virulence properties against S. pyogenes invoke further investigation to study the role of LME as an antibacterial agent to combat streptococcal infections.}, } @article {pmid36559155, year = {2022}, author = {Maurizi, L and Forte, J and Ammendolia, MG and Hanieh, PN and Conte, AL and Relucenti, M and Donfrancesco, O and Ricci, C and Rinaldi, F and Marianecci, C and Carafa, M and Longhi, C}, title = {Effect of Ciprofloxacin-Loaded Niosomes on Escherichia coli and Staphylococcus aureus Biofilm Formation.}, journal = {Pharmaceutics}, volume = {14}, number = {12}, pages = {}, pmid = {36559155}, issn = {1999-4923}, support = {RM11916B797905D6//Sapienza University of Rome/ ; }, abstract = {Infections caused by bacterial biofilms represent a global health problem, causing considerable patient morbidity and mortality in addition to an economic burden. Escherichia coli, Staphylococcus aureus, and other medically relevant bacterial strains colonize clinical surfaces and medical devices via biofilm in which bacterial cells are protected from the action of the immune system, disinfectants, and antibiotics. Several approaches have been investigated to inhibit and disperse bacterial biofilms, and the use of drug delivery could represent a fascinating strategy. Ciprofloxacin (CIP), which belongs to the class of fluoroquinolones, has been extensively used against various bacterial infections, and its loading in nanocarriers, such as niosomes, could support the CIP antibiofilm activity. Niosomes, composed of two surfactants (Tween 85 and Span 80) without the presence of cholesterol, are prepared and characterized considering the following features: hydrodynamic diameter, ζ-potential, morphology, vesicle bilayer characteristics, physical-chemical stability, and biological efficacy. The obtained results suggest that: (i) niosomes by surfactants in the absence of cholesterol are formed, can entrap CIP, and are stable over time and in artificial biological media; (ii) the CIP inclusion in nanocarriers increase its stability, with respect to free drug; (iii) niosomes preparations were able to induce a relevant inhibition of biofilm formation.}, } @article {pmid36558073, year = {2022}, author = {Leska, A and Nowak, A and Czarnecka-Chrebelska, KH}, title = {Adhesion and Anti-Adhesion Abilities of Potentially Probiotic Lactic Acid Bacteria and Biofilm Eradication of Honeybee (Apis mellifera L.) Pathogens.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {24}, pages = {}, pmid = {36558073}, issn = {1420-3049}, support = {729/BN/D/2019//Provincial Fund for Environmental Protection and Water Management in Lodz/ ; }, mesh = {Bees ; Animals ; Humans ; *Lactobacillales ; Caco-2 Cells ; Biofilms ; *Probiotics/pharmacology ; Pediococcus pentosaceus ; }, abstract = {Lactic acid bacteria (LAB) naturally inhabits the organisms of honeybees and can exhibit adhesive properties that protect these insects against various pathogenic microorganisms. Thus, cell surface (auto-aggregation, co-aggregation, hydrophobicity) and adhesive properties of LAB to two abiotic (polystyrene and glass) and four biotic (collagen, gelatin, mucus, and intestinal Caco-2 cells) surfaces were investigated. Additionally, anti-adhesion activity and the eradication of honeybee pathogen biofilms by LAB metabolites (culture supernatants) were determined. The highest hydrophobicity was demonstrated by Pediococcus pentosaceus 19/1 (63.16%) and auto-aggregation by Lactiplantibacillus plantarum 18/1 (71.91%). All LAB showed a broad spectrum of adhesion to the tested surfaces. The strongest adhesion was noted for glass. The ability to co-aggregate with pathogens was tested for the three most potently adherent LAB strains. All showed various levels of co-aggregation depending on the pathogen. The eradication of mature pathogen biofilms by LAB metabolites appeared to be weaker than their anti-adhesive properties against pathogens. The most potent anti-adhesion activity was observed for L. plantarum 18/1 (98.80%) against Paenibacillus apiarius DSM 5582, while the strongest biofilm eradication was demonstrated by the same LAB strain against Melissococcus plutonius DSM 29964 (19.87%). The adhesive and anti-adhesive activity demonstrated by LAB can contribute to increasing the viability of honeybee colonies and improving the conditions in apiaries.}, } @article {pmid36558013, year = {2022}, author = {Li, B and Huang, J and Yi, Y and Liu, S and Liu, R and Xiao, Z and Li, C}, title = {Effects of Rhapontigenin as a Novel Quorum-Sensing Inhibitor on Exoenzymes and Biofilm Formation of Pectobacterium carotovorum subsp. carotovorum and Its Application in Vegetables.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {24}, pages = {}, pmid = {36558013}, issn = {1420-3049}, support = {kq2107022//the Science and Technology Planning Project of Changsha/ ; 2019XK2002//Changsha-Zhuzhou-Xiangtan Landmark Project/ ; 2107022//Changsha Outstanding Innovative Youth Training Program/ ; 2021NK2014//the Key Research & Development Plan of Hunan Province/ ; kq2202224//Key Research & Development Plan of Hunan Province (2022), Natural Science Foundation of Hunan Province (2022). Natural Science Foundation of Changsha/ ; SYL2019061//The third batch of major Scientific Research Projects of Hunan Agricultural University (Innovation Team Cultivation Project 2019) and Double first-class discipline construction project of Hunan Agricultural University/ ; CX20220683//2022 Innovative research Project for postgraduate students of Hunan Province/ ; 2021-63//2021 Innovative research Project for postgraduate students of Hunan Agricultural University/ ; }, mesh = {*Quorum Sensing ; Vegetables ; Pectobacterium carotovorum ; Biofilms ; *Brassica ; Chromobacterium ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The aim of this study was to devise a method to protect Chinese cabbage (Brassica chinensis) and lettuce (Lactuca sativa) from bacterial-disease-induced damage during storage. Thus, the potential of rhapontigenin as a quorum sensing (QS) inhibitor against Pectobacterium carotovorum subsp. carotovorum (P. carotovorum) was evaluated. The QS inhibitory effects of rhapontigenin were confirmed by significant inhibition of the production of violacein in Chromobacterium violaceum CV026 (C. violaceum, CV026). The inhibitory effects of rhapontigenin on the motility, exopolysaccharide (EPS) production, biofilm formation and virulence−exoenzyme synthesis of P. carotovorum were investigated. Acyl-homoserine lactones (AHLs) were quantified using liquid chromatography−mass spectrometry (LC−MS). The inhibitory effects of rhapontigenin on the development of biofilms were observed using fluorescence microscopy and scanning electron microscopy (SEM). A direct-inoculation assay was performed to investigate the QS inhibitory effects of rhapontigenin on P. carotovorum in Chinese cabbage and lettuce. Our results demonstrated that rhapontigenin exhibited significant inhibition (p < 0.05) of the motility, EPS production, biofilm formation, virulence−exoenzyme synthesis and AHL production of P. carotovorum. Additionally, the result of the direct-inoculation assay revealed that rhapontigenin might provide vegetables with significant shelf-life extension and prevent quality loss by controlling the spread of soft-rot symptoms. Consequently, the study provided a significant insight into the potential of rhapontigenin as a QS inhibitor against P. carotovorum.}, } @article {pmid36557761, year = {2022}, author = {Kiel, A and Creutz, I and Rückert, C and Kaltschmidt, BP and Hütten, A and Niehaus, K and Busche, T and Kaltschmidt, B and Kaltschmidt, C}, title = {Genome-Based Analysis of Virulence Factors and Biofilm Formation in Novel P. aeruginosa Strains Isolated from Household Appliances.}, journal = {Microorganisms}, volume = {10}, number = {12}, pages = {}, pmid = {36557761}, issn = {2076-2607}, abstract = {In household washing machines, opportunistic pathogens such as Pseudomonas aeruginosa are present, which represent the household as a possible reservoir for clinical pathogens. Here, four novel P. aeruginosa strains, isolated from different sites of household appliances, were investigated regarding their biofilm formation. Only two isolates showed strong surface-adhered biofilm formation. In consequence of these phenotypic differences, we performed whole genome sequencing using Oxford Nanopore Technology together with Illumina MiSeq. Whole genome data were screened for the prevalence of 285 virulence- and biofilm-associated genes as well as for prophages. Linking biofilm phenotypes and parallelly appearing gene compositions, we assume a relevancy of the las quorum sensing system and the phage-encoded bacteriophage control infection gene bci, which was found on integrated phi297 DNA in all biofilm-forming isolates. Additionally, only the isolates revealing strong biofilm formation harbored the ϕCTX-like prophage Dobby, implicating a role of this prophage on biofilm formation. Investigations on clinically relevant pathogens within household appliances emphasize their adaptability to harsh environments, with high concentrations of detergents, providing greater insights into pathogenicity and underlying mechanisms. This in turn opens the possibility to map and characterize potentially relevant strains even before they appear as pathogens in society.}, } @article {pmid36557738, year = {2022}, author = {Jalil, V and Khan, M and Haider, SZ and Shamim, S}, title = {Investigation of the Antibacterial, Anti-Biofilm, and Antioxidative Effect of Piper betle Leaf Extract against Bacillus gaemokensis MW067143 Isolated from Dental Caries, an In Vitro-In Silico Approach.}, journal = {Microorganisms}, volume = {10}, number = {12}, pages = {}, pmid = {36557738}, issn = {2076-2607}, support = {2018//The University of Lahore/ ; }, abstract = {Among oral diseases, dental caries is one of the most frequent to affect human health. The current research work aimed to ascertain the antibacterial, anti-biofilm, and antioxidative potential of Piper betle leaf extract against bacteria isolated from dental caries. Analysis for the presence of phytochemical compounds revealed compounds, such as tannins, steroids, phenolic compounds, and alkaloids, which were also confirmed by TLC and FTIR. GC-MS analysis elucidated the presence of 20 phytocompounds, among which were some well-reported bioactive compounds. The chloroform extract of P. betle demonstrated good antibacterial activity (7 mm) and minimum inhibitory concentration (MIC) (100 mg mL[-1]) against Bacillus gaemokensis MW067143, which was the frequent biofilm producer among isolated bacterial strains. Fractions of the extract were isolated through column chromatography, after which the antibacterial activity was again evaluated. Spirost-8-en-11-one,3-hydroxy(3β,5α,14β,20β,22β,25R), an oxosteroid in nature, was observed to exhibit remarkable antibacterial potential (12 mm) against B. gaemokensis. Bacterial cells treated with P. betle extract had elevated SOD, APOX, POX, and GR activity, while its proteolytic activity against whole bacterial proteins was pronounced with the suppression of several proteins (50, 40, 15, and 10 kDa) in SDS-PAGE. Bacterial cells treated with P. betle extract demonstrated decreased growth, while the extract was also observed to exhibit inhibition of biofilm formation (70.11%) and demolition of established B. gaemokensis biofilms (57.98%). SEM analysis revealed significant changes to bacterial morphology post treatment with P. betle, with cellular disintegration being prominent. In silico network pharmacology analysis elucidated proteins like ESR1 and IL6 to be majorly involved in biological pathways of dental caries, which also interact with the protective ability of P. betle. Gene Ontology (GO) terms and KEGG pathways were also screened using enrichment analysis. Molecular docking demonstrated the highest binding affinity of Spirost-8-en-11-one,3-hydroxy-,(3β,5α,14β,20β,22β,25R) with bacterial proteins FabI (-12 kcal/mol), MurB (-17.1 kcal/mol), and FtsZ (-14.9 kcal/mol). Therefore, it is suggested that P. betle can serve a potentially therapeutic role and could be used in the preparation of herbal formulations for managing bacterial flora.}, } @article {pmid36557727, year = {2022}, author = {Gaillac, A and Briandet, R and Delahaye, E and Deschamps, J and Vigneau, E and Courcoux, P and Jaffrès, E and Prévost, H}, title = {Exploring the Diversity of Biofilm Formation by the Food Spoiler Brochothrix thermosphacta.}, journal = {Microorganisms}, volume = {10}, number = {12}, pages = {}, pmid = {36557727}, issn = {2076-2607}, support = {0//National Research Institute for Agriculture, Food and Environment/ ; 0//Pays de la Loire region/ ; }, abstract = {Brochothrix thermosphacta is considered as a major spoiler of meat and seafood products. This study explores the biofilm formation ability and the biofilm structural diversity of 30 multi-origin B. thermosphacta strains using a set of complementary biofilm assays (biofilm ring test, crystal violet staining, and confocal laser scanning microscopy). Two major groups corresponding to low and high biofilm producers were identified. High biofilm producers presented flat architectures characterized by high surface coverage, high cell biovolume, and high surface area.}, } @article {pmid36557609, year = {2022}, author = {Ma, G and Ding, Y and Wu, Q and Zhang, J and Liu, M and Wang, Z and Wang, Z and Wu, S and Yang, X and Li, Y and Wei, X and Wang, J}, title = {Yersinia enterocolitica-Derived Outer Membrane Vesicles Inhibit Initial Stage of Biofilm Formation.}, journal = {Microorganisms}, volume = {10}, number = {12}, pages = {}, pmid = {36557609}, issn = {2076-2607}, support = {2020B0301030005//Guangdong Major Project of Basic and Applied Basic Research/ ; 31730070//National Natural Science Foundation of China/ ; 2020B121201009//Guangdong Provincial Key Laboratory/ ; }, abstract = {Yersinia enterocolitica (Y. enterocolitica) is an important food-borne and zoonotic pathogen. It can form biofilm on the surface of food, increasing the risk to food safety. Generally, outer membrane vesicles (OMVs) are spherical nanostructures secreted by Gram-negative bacteria during growth. They play a role in biological processes because they contain biologically active molecules. Several studies have reported that OMVs secreted by various bacteria are associated with the formation of biofilms. However, the interactions between Y. enterocolitica OMVs and biofilm are unknown. This study aims to investigate the effect of Y. enterocolitica OMVs on biofilm formation. Firstly, OMVs were extracted from Y. enterocolitica Y1083, which has a strong biofilm-forming ability, at 15 °C, 28 °C and 37 °C and then characterized. The characterization results showed differences in the yield and protein content of three types of OMVs. Next, by co-culturing the OMVs with Y. enterocolitica, it was observed that the OMVs inhibited the initial stage of Y. enterocolitica biofilm formation but did not affect the growth of Y. enterocolitica. Furthermore, biofilm formation by Salmonella enteritidis and Staphylococcus aureus were also inhibited by OMVs. Subsequently, it was proved that lipopolysaccharides (LPS) in OMVs inhibited biofilm formation., The proteins, DNA or RNA in OMVs could not inhibit biofilm formation. Bacterial motility and the expression of the biofilm-related genes pgaABC, motB and flhBD were inhibited by LPS. LPS demonstrated good anti-biofilm activity against various bacteria. This study provides a new approach to the prevention and control of pathogenic bacterial biofilm.}, } @article {pmid36553778, year = {2022}, author = {Šilha, D and Syrová, P and Syrová, L and Janečková, J}, title = {Smoothie Drinks: Possible Source of Resistant and Biofilm-Forming Microorganisms.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {24}, pages = {}, pmid = {36553778}, issn = {2304-8158}, abstract = {Smoothie drinks are currently very popular drinks sold especially in fast food establishments. However, smoothies are a significant source of microorganisms. The aim of this study was to evaluate the microbiological quality of smoothies purchased in Eastern Bohemia. A higher prevalence of mesophilic aerobic bacteria (5.4-7.2 log CFU/mL), yeast (4.4-5.9 log CFU/mL) and coliform bacteria (3.1-6.0 log CFU/mL) was observed in vegetable smoothies, in which even the occurrence of enterococci (1.6-3.3 log CFU/mL) was observed. However, the occurrence of S. aureus, Salmonella spp. and Listeria spp. was not observed in any samples. Nevertheless, antimicrobial resistance was observed in 71.8% of the isolated strains. The highest level of resistance was found in isolates from smoothie drinks with predominantly vegetable contents (green smoothie drinks). Considerable resistance was observed in Gram-negative rods, especially to amoxicillin (82.2%) and amoxicillin with clavulanic acid (55.6%). Among enterococci, only one vancomycin-resistant strain was detected. The vast majority of isolated strains were able to form biofilms at a significant level, which increases the clinical importance of these microorganisms. The highest biofilm production was found in Pseudomonas aeruginosa, Kocuria kristinae and Klebsiella pneumoniae. Overall, significant biofilm production was also noted among isolates of Candida spp.}, } @article {pmid36552883, year = {2022}, author = {Toc, DA and Csapai, A and Popa, F and Popa, C and Pascalau, V and Tosa, N and Botan, A and Mihaila, RM and Costache, CA and Colosi, IA and Junie, LM}, title = {Easy and Affordable: A New Method for the Studying of Bacterial Biofilm Formation.}, journal = {Cells}, volume = {11}, number = {24}, pages = {}, pmid = {36552883}, issn = {2073-4409}, mesh = {Humans ; *Bacteria ; Biofilms ; *Staphylococcal Infections ; Staphylococcus aureus ; Microscopy, Electron, Scanning ; }, abstract = {BACKGROUND: Bacterial biofilm formation (BBF) proves itself to be in the spotlight of microbiology research due to the wide variety of infections that it can be associated with, the involvement in food spoilage, industrial biofouling and perhaps sewage treatment. However, BBF remains difficult to study due to the lack of standardization of the existing methods and the expensive equipment needed. We aim to describe a new inexpensive and easy to reproduce protocol for a 3D-printed microfluidic device that can be used to study BBF in a dynamic manner.

METHODS: We used the SolidWorks 3D CAD Software (EducationEdition 2019-2020, Dassault Systèmes, Vélizy-Villacoublay, France) to design the device and the Creality3D Ender 5 printer (Shenzhen Creality 3D Technology Co., Ltd., Shenzhen, China) for its manufacture. We cultivated strains of Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. For the biofilm evaluation we used optical coherence tomography (OCT), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and crystal violet staining technique.

RESULTS: Based on the analysis, Enterococcus faecalis seems to produce more biofilm in the first hours while Pseudomonas aeruginosa started to take the lead on biofilm production after 24 h.

CONCLUSIONS: With an estimated cost around €0.1285 for one microfluidic device, a relatively inexpensive and easy alternative for the study of BBF was developed.}, } @article {pmid36551879, year = {2022}, author = {Pedrinha, VF and Cuellar, MRC and de Barros, MC and Titato, PCG and Shahbazi, MA and Sharma, PK and de Andrade, FB}, title = {The Vehicles of Calcium Hydroxide Pastes Interfere with Antimicrobial Effect, Biofilm Polysaccharidic Matrix, and Pastes' Physicochemical Properties.}, journal = {Biomedicines}, volume = {10}, number = {12}, pages = {}, pmid = {36551879}, issn = {2227-9059}, abstract = {The objective of the present study was to investigate the pH, volumetric alteration, antimicrobial action, and effect on biofilm matrix polysaccharides of calcium hydroxide (CH) pastes with different vehicles available in endodontics: CH + propylene glycol (CHP), UltraCal XS[®], Metapaste[®], and Metapex[®]. The pH was analyzed at different time intervals using a pH meter. For volumetric alteration, a microtomographic assay was performed before and after immersion in water. Enterococcus faecalis was chosen for microbiological tests. The bacterial viability and extracellular matrix were quantified with direct contact evaluation (dentin blocks) and at the intratubular level (dentin cylinders) using LIVE/DEAD BacLight and Calcofluor White dyes via confocal laser scanning microscopy (CLSM). Kruskal-Wallis and Dunn's tests were used to analyze pH and direct contact assays, while one-way ANOVA and Tukey tests were used to analyze volumetric alteration and intratubular decontamination (α = 0.05). Higher pH values were obtained during the initial days. Volumetric alterations were similar in all groups. Lower bacterial viability was obtained for dentin blocks and cylinders when CH pastes were used. UltraCal XS and Metapex had lower values for the extracellular matrix. The pH of all CH pastes decreased with time and did not promote medium alkalization for up to 30 days. CH paste can reduce bacterial viability through direct contact and at an intratubular level; however, UltraCal XS and Metapex are involved with lower volumes of extracellular matrices.}, } @article {pmid36551492, year = {2022}, author = {Bozhkova, SA and Gordina, EM and Labutin, DV and Kudryavtsev, KV}, title = {Oligopeptide Sortase Inhibitor Modulates Staphylococcus aureus Cell Adhesion and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {36551492}, issn = {2079-6382}, support = {20-15-00258//Russian Science Foundation/ ; }, abstract = {Prevention of bacterial adhesion is one of the most important antivirulence strategies for meeting the global challenge posed by antimicrobial resistance. We aimed to investigate the influence of a peptidic S. aureus sortase A inhibitor on bacterial adhesion to eukaryotic cells and biofilm formation as a potential method for reducing S. aureus virulence. The pentapeptide LPRDA was synthesized and characterized as a pure individual organic compound. Incubation of MSSA and MRSA strains with LPRDA induced a subsequent reduction in staphylococcal adhesion to Vero cells and biofilm formation, as visualized by microscopic and spectrophotometric methods, respectively. LPRDA did not have a cytotoxic effect on eukaryotic or bacterial cells. The pentapeptide LPRDA deserves further investigation using in vitro and in vivo models of Gram-positive bacteriemia as a potential antibacterial agent with an antiadhesive mechanism of action.}, } @article {pmid36551428, year = {2022}, author = {Maione, A and Pietra, A and Salvatore, MM and Guida, M and Galdiero, E and de Alteriis, E}, title = {Undesired Effect of Vancomycin Prolonged Treatment: Enhanced Biofilm Production of the Nosocomial Pathogen Candida auris.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {36551428}, issn = {2079-6382}, abstract = {Fungal infections are often consequent to prolonged antibiotic treatments. Vancomycin (Van) is the first-choice antibiotic in the treatment of Staphylococcus aureus infections associated with colonization of catheter surfaces. We demonstrate the direct effect of Van in promoting the formation of the biofilm of the emergent yeast pathogen Candida auris, developed in the conventional polystyrene microwell plate model, as well as on silicone surfaces (22 and 28% increase in total biomass, respectively) and on an S. aures biofilm, residual after vancomycin treatment, where C. auris achieved 99% of the mixed biofilm population. The effect of Van was assessed also in vivo, in the Galleria mellonella infection model, which showed higher mortality when infected with the yeast pathogen in the presence of the antibiotic. This evidence enhances awareness of the potential risk associated with prolonged antibiotic use in promoting fungal infections.}, } @article {pmid36551404, year = {2022}, author = {Kostić, M and Ivanov, M and Babić, SS and Tepavčević, Z and Radanović, O and Soković, M and Ćirić, A}, title = {Analysis of Tonsil Tissues from Patients Diagnosed with Chronic Tonsillitis-Microbiological Profile, Biofilm-Forming Capacity and Histology.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {36551404}, issn = {2079-6382}, support = {451-03-68/2022-14/ 200007//Serbian Ministry of Education, Science and Technological Development/ ; }, abstract = {Chronic tonsillitis (CT) is a global health issue which can impair patient's quality of life and has an important socioeconomic impact due to the nonrational use of antibiotics, increased antimicrobial resistance and frequent need for surgical treatment. In order to isolate and identify the causing agents of CT, a total of 79 postoperative palatine and adenoid tissue samples were obtained from the ENT Clinic, KBC Zvezdara, Belgrade, Serbia. Culture identification was performed by MALDI-TOF MS and the Staphylococcus aureus isolates were tested for biofilm forming capability and antibiotic susceptibility. Additionally, a histological examination of palatine and adenoid tissue was performed in order to detect the presence of CT-causing bacteria. The slight majority of participants were females with median age of 28 years for adult patients (group I) and 6 years for children (group II). Analysis of the incidence of bacteria isolated from tissue samples in both groups showed the highest prevalence of S. aureus, Streptococcus oralis and Streptococcus parasanquinis. In addition to interfollicular hyperplasia, colonies of species S. aureus were detected in histological material. The presence of biofilm might be the reason for the recurrence of infection. Therefore, searching for a new treatment of CT is of great importance.}, } @article {pmid36551390, year = {2022}, author = {Leesombun, A and Thanapakdeechaikul, K and Suwannawiang, J and Mukto, P and Sungpradit, S and Bangphoomi, N and Changbunjong, T and Thongjuy, O and Weluwanarak, T and Boonmasawai, S}, title = {Effects of Coleus amboinicus L. Essential Oil and Ethanolic Extracts on Planktonic Cells and Biofilm Formation of Microsporum canis Isolated from Feline Dermatophytosis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {36551390}, issn = {2079-6382}, support = {Funding from Faculty of Veterinary Science-2019//Mahidol University/ ; }, abstract = {Microsporum canis is an important zoonotic fungus that causes dermatophytosis in domestic animals and their owners. Domestic cats are the primary reservoir for M. canis. Antifungal drugs frequently produce adverse effects on the host animal, increasing the demand for novel alternative treatments derived from nature. We evaluated the antifungal activity of Coleus amboinicus essential oil (CEO) and ethanolic extracts (CEE) against M. canis in planktonic and biofilm growth. Twelve clinical isolates of M. canis were identified in feline dermatophyte samples. Using GC-MS, 18 compounds were identified in CEO, with carvacrol being the major constituent. HPLC analysis of CEE revealed that it contained rosmarinic acid, apigenin, and caffeic acid. The planktonic growth of all M. canis isolates was inhibited by C. amboinicus extracts. The minimum inhibitory concentration at which ≥50% of the isolates were inhibited (MIC50) was 128 µg/mL (32-256 µg/mL) for both CEO and CEE. The MIC90 values of CEO and CEE were 128 and 256 µg/mL, respectively. CEO at MIC (128 µg/mL) and 2× MIC (256 µg/mL) significantly inhibited the biofilm formation of weak, moderate, and strong biofilm-producing M. canis. CEE at 2× MIC (256 µg/mL) significantly inhibited the biofilm formation of all isolates. Overall, C. amboinicus extracts inhibited planktonic growth and exhibited a significant antibiofilm effect against M. canis. Thus, C. amboinicus is a potential source of natural antifungal compounds.}, } @article {pmid36551363, year = {2022}, author = {Mukane, L and Racenis, K and Rezevska, D and Petersons, A and Kroica, J}, title = {Anti-Biofilm Effect of Bacteriophages and Antibiotics against Uropathogenic Escherichia coli.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {36551363}, issn = {2079-6382}, abstract = {Escherichia coli is a common cause of biofilm-associated urinary tract infections. Bacteria inside the biofilm are more resistant to antibiotics. Six E. coli strains isolated from patients with urinary tract infections were screened for biofilm-forming capability and antimicrobial susceptibility. Two of the most significant biofilm-producing strains were selected for minimal inhibitory concentration and minimal biofilm eradication concentration in vitro testing using amoxicillin-clavulanic acid, ciprofloxacin, and three commercial bacteriophage cocktails (Pyobacteriophag, Ses, and Intesti). In case of a low phage effect, an adaptation procedure was performed. Although the biofilms formed by strain 021UR were resistant to amoxicillin-clavulanic acid and ciprofloxacin, the three phage cocktails were able to reduce biofilm formation. In contrast, phages did not affect the 01206UR strain against planktonic and biofilm-forming cells. After Pyobacteriophag adaptation, the effect improved, and, regardless of the concentration, the adapted phage cocktail could destroy both planktonic cells and the biofilm of strain 01206UR. Bacteriophages capable of killing bacteria in biofilms can be used as an alternative to antibiotics. However, each case should be considered individually due to the lack of clinical trials for phage therapy. Antimicrobial and phage susceptibility should be determined in biofilm models before treatment to achieve the desired anti-biofilm effect.}, } @article {pmid36549494, year = {2023}, author = {Tang, P and Xu, H and Zhang, W and Zhu, Y and Yang, J and Zhou, Y}, title = {Fluid transport in porous media based on differences in filter media morphology and biofilm growth in bioreactors.}, journal = {Environmental research}, volume = {219}, number = {}, pages = {115122}, doi = {10.1016/j.envres.2022.115122}, pmid = {36549494}, issn = {1096-0953}, mesh = {Porosity ; *Zeolites ; Bioreactors ; Biofilms ; Permeability ; }, abstract = {To elucidate the effect of pore structure on bioclogging and seepage flow in bioreactors, we used X-ray computed tomography (X-CT) to investigate the changes in seepage flow of porous media in zeolite, gravel and ceramsite bioreactors with biofilm growth by injecting a non-ionic contrast medium iohexol. Based on the X-CT images using a ball-and-stick model, the highest average pore radius (R‾) and the average pore throat radius (r‾) in the ceramsite column were found under the initial conditions, which facilitated its permeability. The pore and throat of the gravel column were small and homogeneous relatively. Biofilm growth decreased the pore and pore throat in the columns. The total throat area of zeolite, gravel and ceramsite columns declined by 74%, 73% and 79% respectively. The zeolite column had the highest average pore throat, which contributed to its maximum conductivity subsequently after biofilm growth. Further, the fractal dimensions of the pore structure increased with biofilm growth, especially in the zeolite and ceramsite columns. The heterogeneity of the porous media was reinforced by the biofilm growth in the zeolite and ceramsite columns due to their higher heterogeneity initially. We also observed that an increase in heterogeneity of porous medium amplified the preferential flow and flow heterogeneities, especially in the zeolite and ceramsite columns.}, } @article {pmid36549042, year = {2023}, author = {Liu, D and Xi, Y and Yu, S and Yang, K and Zhang, F and Yang, Y and Wang, T and He, S and Zhu, Y and Fan, Z and Du, J}, title = {A polypeptide coating for preventing biofilm on implants by inhibiting antibiotic resistance genes.}, journal = {Biomaterials}, volume = {293}, number = {}, pages = {121957}, doi = {10.1016/j.biomaterials.2022.121957}, pmid = {36549042}, issn = {1878-5905}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Antimicrobial Cationic Peptides/pharmacology ; *Biofilms/drug effects ; *Coated Materials, Biocompatible/pharmacology ; Dihydroxyphenylalanine/pharmacology ; Escherichia coli ; Polymers/pharmacology ; Staphylococcus aureus/drug effects ; *Titanium/pharmacology ; Prostheses and Implants/microbiology ; Drug Resistance, Bacterial ; }, abstract = {Aging population has been boosting the need for orthopedic implants. However, biofilm has been a major obstacle for orthopedic implants due to its insensitivity to antibiotics and tendency to drive antimicrobial resistance. Herein, an antibacterial polypeptide coating with excellent in vivo adhesive capacity was prepared to prevent implants from forming biofilms and inducing acquired antibiotic resistance. A peptide-based copolymer, poly[phenylalanine10-stat-lysine12]-block-3,4-dihydroxy-l-phenylalanine [Poly(Phe10-stat-Lys12)-DOPA] was modularly designed, where poly(Phe10-stat-Lys12) is antibacterial polypeptide with high antibacterial activity, and DOPA provides strong adhesion in both wet and dry microenvironments. Meanwhile, compared to traditional "graft-onto" methods, this antibacterial coating can be facilely achieved by immersing Titanium substrates into antibacterial polypeptide solution for 5 min at room temperature. The poly(Phe10-stat-Lys12)-DOPA polymer showed good antibacterial activity with minimum inhibitory concentrations against S. aureus and E. coli of 32 and 400 μg/mL, respectively. Compared to obvious antimicrobial resistance of S. aureus after continuous treatment with vancomycin, this antibacterial coating doesn't drive antimicrobial resistance upon long-term utilization. Transcriptome sequencing and qPCR tests further confirmed that the antibacterial coating was able to inhibit the expression of multiple peptide resistance factor (mprF) and lipoteichoic acid modification D-alanylation genes (dltB and dltC) that can increase the net positive charge of bacterial cell wall to induce the resistance to cationic antimicrobial peptides. In vivo experiments confirmed that this poly(Phe10-stat-Lys12)-DOPA coating can both effectively prevent biofilm formation through surface contact sterilization and avoid local and systemic infections. Overall, we proposed a facile method for preparing antibacterial orthopedic implants with longer indwelling time and without inducing antimicrobial resistance by coating a polypeptide-based polymer on the implants.}, } @article {pmid36548624, year = {2022}, author = {Guerrieri, N and Fantozzi, L and Lami, A and Musazzi, S and Austoni, M and Orrù, A and Marziali, L and Borgonovo, G and Scaglioni, L}, title = {Biofilm and Rivers: The Natural Association to Reduce Metals in Waters.}, journal = {Toxics}, volume = {10}, number = {12}, pages = {}, pmid = {36548624}, issn = {2305-6304}, abstract = {This article focuses on a very peculiar habitat, the thin biofilm that covers the surface of rocks, cobbles, sediment grains, leaf litter, and vegetation on a riverbed. Species composition changes over time and depends on environmental conditions and perturbation of water quality. It provides several ecosystem services, contributing to the biogeochemical fluxes and reducing contamination by absorbing the pollutants. Biofilm into the Toce River (Ossola Valley, Piedmont, Italy) was investigated to assess its capacity to accumulate the metals and macroions from the water column. In this preliminary work, we investigated three sample points, in two different seasons. The community composition of biofilm was determined via morphological analysis (diatoms and non-diatoms algal community). We characterize the biofilm, a community of different organisms, from different perspectives. In the biofilm, Hg was analyzed with an automated mercury analyzer, other metals and macroions with inductively coupled plasma mass spectrometry (ICP-MS) (Al, As, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, and Zn), and the carotenoid and chlorophyll composition of the photosynthetic organism with HPLC analysis for the primary producers. The results evidence a seasonal pattern in metals and macroions levels in the biofilm, and a significant difference in the biofilm community and in carotenoid composition, suggesting the utility of using the biofilm as an additional bioindicator to monitor the water quality of the river.}, } @article {pmid36548227, year = {2022}, author = {Winans, JB and Wucher, BR and Nadell, CD}, title = {Multispecies biofilm architecture determines bacterial exposure to phages.}, journal = {PLoS biology}, volume = {20}, number = {12}, pages = {e3001913}, pmid = {36548227}, issn = {1545-7885}, mesh = {*Bacteriophages ; Escherichia coli ; Biofilms ; *Vibrio cholerae ; Extracellular Polymeric Substance Matrix ; }, abstract = {Numerous ecological interactions among microbes-for example, competition for space and resources, or interaction among phages and their bacterial hosts-are likely to occur simultaneously in multispecies biofilm communities. While biofilms formed by just a single species occur, multispecies biofilms are thought to be more typical of microbial communities in the natural environment. Previous work has shown that multispecies biofilms can increase, decrease, or have no measurable impact on phage exposure of a host bacterium living alongside another species that the phages cannot target. The reasons underlying this variability are not well understood, and how phage-host encounters change within multispecies biofilms remains mostly unexplored at the cellular spatial scale. Here, we study how the cellular scale architecture of model 2-species biofilms impacts cell-cell and cell-phage interactions controlling larger scale population and community dynamics. Our system consists of dual culture biofilms of Escherichia coli and Vibrio cholerae under exposure to T7 phages, which we study using microfluidic culture, high-resolution confocal microscopy imaging, and detailed image analysis. As shown previously, sufficiently mature biofilms of E. coli can protect themselves from phage exposure via their curli matrix. Before this stage of biofilm structural maturity, E. coli is highly susceptible to phages; however, we show that these bacteria can gain lasting protection against phage exposure if they have become embedded in the bottom layers of highly packed groups of V. cholerae in co-culture. This protection, in turn, is dependent on the cell packing architecture controlled by V. cholerae biofilm matrix secretion. In this manner, E. coli cells that are otherwise susceptible to phage-mediated killing can survive phage exposure in the absence of de novo resistance evolution. While co-culture biofilm formation with V. cholerae can confer phage protection to E. coli, it comes at the cost of competing with V. cholerae and a disruption of normal curli-mediated protection for E. coli even in dual species biofilms grown over long time scales. This work highlights the critical importance of studying multispecies biofilm architecture and its influence on the community dynamics of bacteria and phages.}, } @article {pmid36547900, year = {2022}, author = {Zhang, MJ and Yun, ST and Wang, XC and Peng, LY and Dou, C and Zhou, YX}, title = {Insights into the Influence of Signal Peptide on the Enzymatic Properties of Alginate Lyase AlyI1 with Removal Effect on Pseudomonas aeruginosa Biofilm.}, journal = {Marine drugs}, volume = {20}, number = {12}, pages = {}, pmid = {36547900}, issn = {1660-3397}, support = {31700116//National Natural Science Foundation of China/ ; ZR2017MC019//Natural Science Foundation of Shandong Province/ ; 2017M62218//China Postdoctoral Science Foundation/ ; 1070413421511//The Key Science and Technology Program of Weihai/ ; }, mesh = {Alginates/chemistry/metabolism ; *Biofilms/drug effects ; Hydrogen-Ion Concentration ; *Polysaccharide-Lyases/chemistry/pharmacology ; *Protein Sorting Signals ; *Pseudomonas aeruginosa/physiology ; Substrate Specificity ; *Flavobacteriaceae/enzymology ; }, abstract = {Most reports on signal peptides focus on their ability to affect the normal folding of proteins, thereby affecting their secreted expression, while few studies on its effects on enzymatic properties were published. Therefore, biochemical characterization and comparison of alginate lyase rALYI1/rALYI1-1 (rALYI1: without signal peptides; rALYI1-1:with signal peptides) were conducted in our study, and the results showed that the signal peptide affected the biochemical properties, especially in temperature and pH. rALYI1 (32.15 kDa) belonging to polysaccharide lyase family 7 was cloned from sea-cucumber-gut bacterium Tamlana sp. I1. The optimum temperature of both rALYI1 and rALYI1-1 was 40 °C, but the former had a wider optimum temperature range and better thermal stability. The optimum pH of rALYI1 and rALYI1-1 were 7.6 and 8.6, respectively. The former was more stable and acid resistant. Noticeably, rALYI1 was a salt-activated enzyme and displayed remarkable salt tolerance. Alginate, an essential polysaccharide in algae and Pseudomonas aeruginosa biofilms, is composed of α-L-guluronate and β-D-mannuronate. It is also found in our study that rALYI1 is also effective in removing mature biofilms compared with controls. In conclusion, the signal peptide affects several biochemical properties of the enzyme, and alginate lyase rALYI1 may be an effective method for inhibiting biofilm formation of Pseudomonas aeruginosa.}, } @article {pmid36547894, year = {2022}, author = {D'Angelo, C and Casillo, A and Melchiorre, C and Lauro, C and Corsaro, MM and Carpentieri, A and Tutino, ML and Parrilli, E}, title = {CATASAN Is a New Anti-Biofilm Agent Produced by the Marine Antarctic Bacterium Psychrobacter sp. TAE2020.}, journal = {Marine drugs}, volume = {20}, number = {12}, pages = {}, pmid = {36547894}, issn = {1660-3397}, mesh = {Humans ; *Psychrobacter ; Anti-Bacterial Agents/chemistry ; Chromatography, Liquid ; Tandem Mass Spectrometry ; Biofilms ; Staphylococcus epidermidis ; }, abstract = {The development of new approaches to prevent microbial surface adhesion and biofilm formation is an emerging need following the growing understanding of the impact of biofilm-related infections on human health. Staphylococcus epidermidis, with its ability to form biofilm and colonize biomaterials, represents the most frequent causative agent involved in infections of medical devices. In the research of new anti-biofilm agents against S. epidermidis biofilm, Antarctic marine bacteria represent an untapped reservoir of biodiversity. In the present study, the attention was focused on Psychrobacter sp. TAE2020, an Antarctic marine bacterium that produces molecules able to impair the initial attachment of S. epidermidis strains to the polystyrene surface. The setup of suitable purification protocols allowed the identification by NMR spectroscopy and LC-MS/MS analysis of a protein-polysaccharide complex named CATASAN. This complex proved to be a very effective anti-biofilm agent. Indeed, it not only interferes with cell surface attachment, but also prevents biofilm formation and affects the mature biofilm matrix structure of S. epidermidis. Moreover, CATASAN is endowed with a good emulsification activity in a wide range of pH and temperature. Therefore, its use can be easily extended to different biotechnological applications.}, } @article {pmid36547797, year = {2023}, author = {Bezerra, K and Iukava, LK and Ono, JM and de Souza, SGP and Dos Santos, IC and Barbosa, LN}, title = {Resistance profile and biofilm production capacity of Staphylococcus spp. beef slaughterhouse isolates and their sensitivity to Rosmarinus officinalis essential oil.}, journal = {Veterinary research communications}, volume = {47}, number = {2}, pages = {911-919}, pmid = {36547797}, issn = {1573-7446}, mesh = {Cattle ; Animals ; Staphylococcus ; *Rosmarinus ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Coagulase/genetics ; Abattoirs ; Anti-Bacterial Agents/pharmacology ; Staphylococcus aureus ; *Staphylococcal Infections/veterinary/microbiology ; Biofilms ; *Oils, Volatile/pharmacology ; Microbial Sensitivity Tests/veterinary ; *Cattle Diseases ; }, abstract = {Microorganisms can interfere with meat quality, being a public health problem. The aim of this study was to characterize the antimicrobial susceptibility profile of Staphylococcus spp. isolated from utensils of a bovine slaughterhouse and to evaluate the antibacterial and antibiofilm activity of the essential oil of Rosmarinus officinalis L. (rosemary). Samples of surfaces and utensils used during slaughter in the northwest of the state of Paraná, Brazil were collected. After isolation and differentiation of the isolates by the coagulase test, the antimicrobial susceptibility test, Staphylococcus aureus identification and mecA gene research were performed. The study for biofilm production was carried out by the method of adhesion in borosilicate tube and by adhesion in polystyrene plate. Subsequently, the inhibitory activity of the R. officinalis essential oil and its ability to inhibit biofilm were investigated. Twenty-two of the samples collected were identified as coagulase-negative Staphylococcus and five as coagulase-positive Staphylococcus. There was resistance to all antibiotics tested, with clindamycin (33.33%) and rifampicin (29.6%) showing the highest rate. None of the samples was confirmed as Staphylococcus aureus or for the presence of the mecA resistance gene. The essential oil inhibited the growth of 48% of the isolates at a concentration of 16,000 µg/mL. Of these isolates, 33% were positive for biofilm production and this biofilm was also inhibited by the essential oil. This work revealed that multidrug-resistant Staphylococcus and biofilm producers are present in the slaughter environment and are susceptible to the essential oil of R. officinalis.}, } @article {pmid36547646, year = {2022}, author = {Deng, Q and Lei, X and Zhang, H and Deng, L and Yi, L and Zeng, K}, title = {Phenylalanine Promotes Biofilm Formation of Meyerozyma caribbica to Improve Biocontrol Efficacy against Jujube Black Spot Rot.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {12}, pages = {}, pmid = {36547646}, issn = {2309-608X}, support = {2019YFD1002300//National Key Research and Development Program of China/ ; }, abstract = {During storage and transportation after harvest, the jujube fruit is susceptible to black spot rot, which is caused by Alternaria alternata. The present study aimed to evaluate the effectiveness of the yeast Meyerozyma caribbica in controlling A. alternata in postharvest jujube fruits, and to explore the biofilm formation mechanism. The results showed that M. caribbica treatment significantly reduced the A. alternata decay in jujube fruits. M. caribbica could rapidly colonize jujube fruit wounds, adhering tightly to hyphae of A. alternata, and accompanied by the production of extracellular secretions. In in vitro experiments, we identified that M. caribbica adhered to polystyrene plates, indicating a strong biofilm-forming ability. Furthermore, we demonstrated that M. caribbica can secrete phenylethanol, a quorum sensing molecule which can affect biofilm development. Phenylalanine (a precursor substance for phenylethanol synthesis) enhanced the secretion of phenylethanol and promoted the formation of M. caribbica biofilms. Meanwhile, phenylalanine enhanced the biological control performance of M. caribbica against jujube black spot rot. Our study provided new insights that enhance the biological control performance of antagonistic yeast.}, } @article {pmid36547631, year = {2022}, author = {Kamli, MR and Sabir, JSM and Malik, MA and Ahmad, A}, title = {Characterization of Defensin-like Protein 1 for Its Anti-Biofilm and Anti-Virulence Properties for the Development of Novel Antifungal Drug against Candida auris.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {12}, pages = {}, pmid = {36547631}, issn = {2309-608X}, support = {IFPRC-085-130-2020//Ministry of Education in Saudi Arabia/ ; }, abstract = {Candida auris has emerged as a pan-resistant pathogenic yeast among immunocompromised patients worldwide. As this pathogen is involved in biofilm-associated infections with serious medical manifestations due to the collective expression of pathogenic attributes and factors associated with drug resistance, successful treatment becomes a major concern. In the present study, we investigated the candidicidal activity of a plant defensin peptide named defensin-like protein 1 (D-lp1) against twenty-five clinical strains of C. auris. Furthermore, following the standard protocols, the D-lp1 was analyzed for its anti-biofilm and anti-virulence properties. The impact of these peptides on membrane integrity was also evaluated. For cytotoxicity determination, a hemolytic assay was conducted using horse blood. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values ranged from 0.047-0.78 mg/mL and 0.095-1.56 mg/mL, respectively. D-lp1 at sub-inhibitory concentrations potentially abrogated both biofilm formation and 24-h mature biofilms. Similarly, the peptide severely impacted virulence attributes in the clinical strain of C. auris. For the insight mechanism, D-lp1 displayed a strong impact on the cell membrane integrity of the test pathogen. It is important to note that D-lp1 at sub-inhibitory concentrations displayed minimal hemolytic activity against horse blood cells. Therefore, it is highly useful to correlate the anti-Candida property of D-lp1 along with anti-biofilm and anti-virulent properties against C. auris, with the aim of discovering an alternative strategy for combating serious biofilm-associated infections caused by C. auris.}, } @article {pmid36547112, year = {2022}, author = {Bagheri, R and Bohlouli, S and Maleki Dizaj, S and Shahi, S and Memar, MY and Salatin, S}, title = {The Antimicrobial and Anti-Biofilm Effects of Hypericum perforatum Oil on Common Pathogens of Periodontitis: An In Vitro Study.}, journal = {Clinics and practice}, volume = {12}, number = {6}, pages = {1009-1019}, pmid = {36547112}, issn = {2039-7275}, support = {66911//Tabriz University of Medical Sciences/ ; }, abstract = {The antibacterial and anti-biofilm effects of Hypericum perforatum oil against the common pathogens of periodontitis (Escherichia coli, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Porphyromonas gingivalis) was investigated. Disk diffusion (DD), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) approaches were applied to test the antimicrobial effects. In order to determine the anti-biofilm effects, the amount of bacterial biofilm formation was assessed using the microtiter plate technique. The anti-biofilm effects were then confirmed by determining the minimum biofilm inhibitor concentration (MBIC). The MIC, MBC, MBIC, and DD values were 64, 256, 512 μg/mL, and 14 mm for Staphylococcus aureus; 128, 256, 512 μg/mL, and 16 mm for Streptococcus mutans; 256, 512, 256 μg/mL, and 20 mm for Escherichia coli; 32, 128, 512 µg/mL, and 16 mm for Enterococcus faecalis; and 64, 128, 256 µg/mL, and 15 mm for Porphyromonas gingivalis, respectively. According to our results, Hypericum perforatum oil has antibacterial and anti-biofilm properties against the common bacteria associated with periodontitis.}, } @article {pmid36546942, year = {2022}, author = {Marji, SM and Bayan, MF and Jaradat, A}, title = {Facile Fabrication of Methyl Gallate Encapsulated Folate ZIF-L Nanoframeworks as a pH Responsive Drug Delivery System for Anti-Biofilm and Anticancer Therapy.}, journal = {Biomimetics (Basel, Switzerland)}, volume = {7}, number = {4}, pages = {}, pmid = {36546942}, issn = {2313-7673}, abstract = {Zeolitic imidazole frameworks are emerging materials and have been considered an efficient platform for biomedical applications. The present study highlights the simple fabrication of methyl gallate encapsulated folate-ZIF-L nanoframeworks (MG@Folate ZIF-L) by a simple synthesis. The nanoframeworks were characterized by different sophisticated instruments. In addition, the drug-releasing mechanism was evidenced by in vitro releasing kinetics at various pH conditions. The anti-biofilm potential confirmed by the biofilm architectural deformations against human infectious pathogens MRSA and N7 clinical strains. Furthermore, anticancer efficacy assessed against A549 lung cancer cells. The result reveals that the MG@Folate ZIF-L exposed a superior cytotoxic effect due to the pH-responsive and receptor-based drug-releasing mechanism. Based on the unique physicochemical and biological characteristics of nanoframeworks, it has overcome the problems of undesired side effects and uncontrolled drug release of existing drug delivery systems. Finally, the in vitro toxicity effect of MG@Folate ZIF-L was tested against the Artemia salina (A. salina) model organism, and the results show enhanced biocompatibility. Overall, the study suggested that the novel MG@Folate ZIF-L nanoframeworks is a suitable material for biomedical applications. It will be very helpful to the future design for targeted drug delivery systems.}, } @article {pmid36545821, year = {2023}, author = {Li, X and Li, W and Li, K and Chen, X and Wang, C and Qiao, M and Hong, W}, title = {Albumin-coated pH-responsive dimeric prodrug-based nano-assemblies with high biofilm eradication capacity.}, journal = {Biomaterials science}, volume = {11}, number = {3}, pages = {1031-1041}, doi = {10.1039/d2bm01520j}, pmid = {36545821}, issn = {2047-4849}, mesh = {Humans ; Animals ; Mice ; *Prodrugs/pharmacology/therapeutic use ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Azithromycin/pharmacology/therapeutic use ; Tobramycin/chemistry/pharmacology/therapeutic use ; Biofilms ; *Cystic Fibrosis/drug therapy/microbiology ; Polymers/pharmacology ; Hydrogen-Ion Concentration ; Pseudomonas aeruginosa ; Microbial Sensitivity Tests ; Mammals ; }, abstract = {Pseudomonas aeruginosa (PA) biofilms cause many persistent chronic infections in humans, especially in cystic fibrosis (CF) patients. The biofilms form a strong barrier which may inhibit antimicrobial agents from penetrating the biofilms and killing PA bacteria that reside deep within the biofilms. Concomitant therapies based on tobramycin (TOB) and azithromycin (AZM) have demonstrated beneficial effects in CF patients with chronic PA infections. However, the co-delivery of TOB and AZM has rarely been reported. In this study, we constructed a self-assembled pH-sensitive nano-assembly (DPNA) based on a dimeric prodrug (AZM-Cit-TOB) by simply inserting citraconic amide bonds between AZM and TOB. Moreover, the cationic surface of DPNA was further modified with anionic albumin (HSA) via electrostatic interactions to form an electrostatic complex (termed HSA@DPNA) for better biocompatibility. Upon arrival at the infected tissues, the citraconic amide bonds would be cleaved at acidic pH, resulting in the release of TOB and AZM for bacteria killing and biofilm eradication. As expected, HSA@DPNA showed comparable antibacterial abilities against the P. aeruginosa strain PAO1 in both planktonic and biofilm modes of growth compared to the TOB/AZM mixture in vitro. Moreover, HSA@DPNA exhibited excellent therapeutic efficacy on mice with PAO1-induced lung infection compared to the TOB/AZM mixture, and no detectable toxicity to mammalian cells/animals was observed during the therapeutic process. In summary, our study provides a promising method for the co-delivery of AZM and TOB in concomitant therapies against PAO1-related infection.}, } @article {pmid36544910, year = {2022}, author = {Levipan, HA and Irgang, R and Opazo, LF and Araya-León, H and Avendaño-Herrera, R}, title = {Collective behavior and virulence arsenal of the fish pathogen Piscirickettsia salmonis in the biofilm realm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1067514}, pmid = {36544910}, issn = {2235-2988}, mesh = {Animals ; Virulence ; *Piscirickettsiaceae Infections/veterinary/microbiology ; Mass Behavior ; Fishes/microbiology ; Salmon/microbiology ; Biofilms ; *Fish Diseases/microbiology ; }, abstract = {Piscirickettsiosis is a fish disease caused by the Gram-negative bacterium Piscirickettsia salmonis. This disease has a high socio-economic impact on the Chilean salmonid aquaculture industry. The bacterium has a cryptic character in the environment and their main reservoirs are yet unknown. Bacterial biofilms represent a ubiquitous mechanism of cell persistence in diverse natural environments and a risk factor for the pathogenesis of several infectious diseases, but their microbiological significance for waterborne veterinary diseases, including piscirickettsiosis, have seldom been evaluated. This study analyzed the in vitro biofilm behavior of P. salmonis LF-89[T] (genogroup LF-89) and CA5 (genogroup EM-90) using a multi-method approach and elucidated the potential arsenal of virulence of the P. salmonis LF-89[T] type strain in its biofilm state. P. salmonis exhibited a quick kinetics of biofilm formation that followed a multi-step and highly strain-dependent process. There were no major differences in enzymatic profiles or significant differences in cytotoxicity (as tested on the Chinook salmon embryo cell line) between biofilm-derived bacteria and planktonic equivalents. The potential arsenal of virulence of P. salmonis LF-89[T] in biofilms, as determined by whole-transcriptome sequencing and differential gene expression analysis, consisted of genes involved in cell adhesion, polysaccharide biosynthesis, transcriptional regulation, and gene mobility, among others. Importantly, the global gene expression profiles of P. salmonis LF-89[T] were not enriched with virulence-related genes upregulated in biofilm development stages at 24 and 48 h. An enrichment in virulence-related genes exclusively expressed in biofilms was also undetected. These results indicate that early and mature biofilm development stages of P. salmonis LF-89[T] were transcriptionally no more virulent than their planktonic counterparts, which was supported by cytotoxic trials, which, in turn, revealed that both modes of growth induced important and very similar levels of cytotoxicity on the salmon cell line. Our results suggest that the aforementioned biofilm development stages do not represent hot spots of virulence compared with planktonic counterparts. This study provides the first transcriptomic catalogue to select specific genes that could be useful to prevent or control the (in vitro and/or in vivo) adherence and/or biofilm formation by P. salmonis and gain further insights into piscirickettsiosis pathogenesis.}, } @article {pmid36543072, year = {2023}, author = {Sun, XL and Xiang, H and Xiong, HQ and Fang, YC and Wang, Y}, title = {Bioremediation of microplastics in freshwater environments: A systematic review of biofilm culture, degradation mechanisms, and analytical methods.}, journal = {The Science of the total environment}, volume = {863}, number = {}, pages = {160953}, doi = {10.1016/j.scitotenv.2022.160953}, pmid = {36543072}, issn = {1879-1026}, mesh = {Humans ; *Microplastics ; Plastics/analysis ; Ecosystem ; Biodegradation, Environmental ; *Water Pollutants, Chemical/analysis ; Biofilms ; Fresh Water ; Environmental Monitoring/methods ; }, abstract = {Microplastics, defined as particles <5 mm in diameter, are emerging environmental pollutants that pose a threat to ecosystems and human health. Biofilm degradation of microplastics may be an ecologically friendly approach. This review systematically summarises the factors affecting biofilm degradation of microplastics and proposes feasible methods to improve the efficiency of microplastic biofilm degradation. Environmentally insensitive microorganisms were screened, optimized, and commercially cultured to facilitate the practical application of this technology. For strain screening, technology should focus on microorganisms/strains that can modify the hydrophobicity of microplastics, degrade the crystalline zone of microplastics, and metabolise additives in microplastics. The biodegradation mechanism is also described; microorganisms secreting extracellular oxidases and hydrolases are key factors for degradation. Measuring the changes in molecular weight distribution (MWD) enables better analysis of the biodegradation behaviour of microplastics. Biofilm degradation of microplastics has relatively few applications because of its low efficiency; however, enrichment of microplastics in freshwater environments and wastewater treatment plant tailwater is currently the most effective method for treating microplastics with biofilms.}, } @article {pmid36543040, year = {2023}, author = {Manchanda, S and Cheung, BPK and Lee, GHM and Lo, ECM and Yiu, CKY}, title = {Quantitative analysis of salivary and biofilm bacteria associated with cavitated and non-cavitated carious lesions in pre-school children.}, journal = {Archives of oral biology}, volume = {146}, number = {}, pages = {105607}, doi = {10.1016/j.archoralbio.2022.105607}, pmid = {36543040}, issn = {1879-1506}, mesh = {Humans ; Child, Preschool ; Child ; *Dental Caries/microbiology ; Streptococcus mutans ; Polymerase Chain Reaction ; Biofilms ; Saliva/microbiology ; }, abstract = {OBJECTIVE: To quantify and compare Streptococcus mutans (S. mutans) and Lactobacillus fermentum (L. fermentum) in saliva and biofilm of caries-free children to those with cavitated and non-cavitated lesions.

DESIGN: One hundred and thirty-five 3-4 years old children were grouped (n = 45 in each group) according to their caries status: Clinical examination was done by a calibrated examiner. Biofilm and saliva were collected to quantify the microorganisms using qRT-PCR. The decayed-missing-filled surfaces (dmfs) was calculated by adding the number of decayed (ICDAS-II score 3-6), filled (ICDAS-II score 7 and 8) and missing (ICDAS-II score 9) surfaces due to caries. The correlation between the bacterial amounts and the number of carious surfaces was evaluated using Spearman's correlation coefficient. The levels and proportions of the microorganisms were compared using the Kruskal-Wallis test at an α-level of 0.05.

RESULTS: The quantity of S. mutans and L. fermentum was significantly higher in saliva and biofilm of children with cavitated lesions, followed by those with non-cavitated lesions and the lowest in caries-free children. Also, salivary and biofilm S. mutans, along with biofilm L. fermentum levels, significantly correlated with the number of non-cavitated surfaces; while salivary and biofilm S. mutans and L. fermentum levels significantly correlated with the number of cavitated surfaces. Additionally, dmfs scores significantly correlated with the salivary and biofilm S. mutans and L. fermentum levels.

CONCLUSIONS: S. mutans and L. fermentum in saliva and biofilm samples are associated with caries lesion severity.}, } @article {pmid36542391, year = {2023}, author = {Colamarino, AN and Johnson, TM and Boudreaux, DM and Dutner, JM and Stancoven, BW and Lincicum, AR and Akers, JA}, title = {Influence of Lactobacillus reuteri, Bifidobacterium animalis subsp. lactis, and prebiotic inulin on dysbiotic dental biofilm composition ex vivo.}, journal = {Journal of periodontology}, volume = {94}, number = {6}, pages = {793-804}, doi = {10.1002/JPER.22-0505}, pmid = {36542391}, issn = {1943-3670}, support = {//Uniformed Services University of the Health Sciences/ ; //Fort Gordon Dental Health Activity/ ; }, mesh = {Humans ; Prebiotics ; *Bifidobacterium animalis ; Inulin/pharmacology ; *Limosilactobacillus reuteri ; RNA, Ribosomal, 16S/genetics ; *Probiotics/pharmacology/therapeutic use ; Bacteria ; Biofilms ; *Periodontitis ; }, abstract = {BACKGROUND: Probiotic bacterial supplementation has shown promising results in the treatment of periodontitis and the maintenance of periodontal health. The purpose of this investigation was to evaluate the influence of Lactobacillus reuteri or Bifidobacterium animalis subsp. lactis supplementation with and without prebiotic inulin on biofilm composition using an ex vivo biofilm model.

METHODS: Subgingival plaque specimens from three periodontitis-affected human donors were used to grow biofilms on hydroxyapatite disks in media supplemented with varying combinations of prebiotic inulin, Lactobacillus reuteri, and Bifidobacterium animalis subsp. lactis. Relative abundances of bacterial genera present in mature biofilms were evaluated using 16S rRNA next-generation sequencing. Diversity metrics of microbial communities were evaluated using a next-generation microbiome bioinformatics platform.

RESULTS: Inulin supplementation produced statistically significant dose-dependent increases in relative abundances of Lactobacillus and Bifidobacterium species (p < 0.001) with concomitant decreases in relative abundances of Streptococcus, Veillonella, Fusobacterium, Parvimonas, and Prevotella species (p < 0.001). Inoculation with L. reuteri or B. animalis subsp. lactis increased the relative abundance of only the supplemented probiotic genera (p < 0.05). Supplemental inulin led to a statistically significant decrease in biofilm alpha diversity (p < 0.001).

CONCLUSIONS: The described ex vivo model appears suitable for investigating the effects of probiotic bacteria, prebiotic oligosaccharides, and combinations thereof on biofilm composition and complexity. Within the limitations imposed by this model, results from the present study underscore the potential for prebiotic inulin to modify biofilm composition favorably. Additional research further elucidating biologic rationale and controlled clinical research defining therapeutic benefits is warranted.}, } @article {pmid36542185, year = {2022}, author = {Hou, B and Wang, CY and Li, SW and Zhou, LJ and Che, YL and Chen, QY}, title = {Effects of Toxin-Antitoxin System HicAB on Biofilm Formation by Extraintestinal Pathogenic E. coli.}, journal = {Current microbiology}, volume = {80}, number = {1}, pages = {50}, pmid = {36542185}, issn = {1432-0991}, support = {31802190//National Natural Science Foundation of China/ ; 2018J05053//Natural Science Foundation of Fujian Province/ ; }, mesh = {Humans ; Escherichia coli ; *Extraintestinal Pathogenic Escherichia coli/genetics/metabolism ; *Escherichia coli Proteins/genetics/metabolism ; *Toxin-Antitoxin Systems/genetics ; Biofilms ; *Escherichia coli Infections/microbiology ; }, abstract = {The type II toxin-antitoxin (T-A) HicAB system is abundant in several bacteria and archaea, such as Escherichia coli, Burkholderia Pseudomallei, Yersinia pestis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. This system engages in stress response, virulence, and bacterial persistence. This study showed that the biofilm-forming ability of the hicAB deletion mutant was significantly decreased to moderate ability compared to the extra-intestinal pathogenic Escherichia coli (ExPEC) parent strain and the complemented strain, which are strong biofilm producers. Congo red assay showed that the hicAB mutant maintained the ability to form curli fimbriae. Using RNA-seq and comparative real-time quantitative RT-PCR, we observed the difference in gene expression between the hicAB mutant and the parent strain, which was associated with biofilm formation. Our data indicate that the HicAB type II T-A system has a key role in biofilm formation by ExPEC, which may be associated with outer membrane protein (OMP) gene expression. Collectively, our results indicate that the hicAB type II T-A system is involved in ExPEC biofilm formation.}, } @article {pmid36541679, year = {2023}, author = {Barman, S and Mukherjee, S and Bhattacharjee, B and De, K and Mukherjee, R and Haldar, J}, title = {Biocide loaded shear-thinning hydrogel with anti-biofilm efficacy cures topical infection.}, journal = {Biomaterials science}, volume = {11}, number = {3}, pages = {998-1012}, doi = {10.1039/d2bm01582j}, pmid = {36541679}, issn = {2047-4849}, mesh = {Mice ; Animals ; Hydrogels ; *Disinfectants ; *Methicillin-Resistant Staphylococcus aureus ; *Anti-Infective Agents ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The continuous intervention of multidrug-resistant (MDR) bacterial infections worsens and slows the dynamicity of natural wound healing processes. Fortunately, antibiotics, metal ions, or metal nanoparticle-loaded antimicrobial hydrogels have been developed to tackle infections at injury sites and speed up the healing process. Despite their success, these marketed released based hydrogels are still limited owing to their lack of broad-spectrum activity, inability to tackle biofilm-associated infections, susceptibility towards resistance development, fast release kinetics, and mild to moderate toxicity. To address these shortcomings, we report the development of a biocompatible, shear-thinning, injectable gellan-gelatin hydrogel loaded with a peptidomimetic potent biocide (ASAM-10). The hydrogel upon sustained biocide release (60% within 72 h), displays a broad-spectrum antibacterial activity with negligible in vitro (hemolysis < 20%) and in vivo toxicity (no adverse effects on dermal layer of mice). Besides tackling bacterial dormant subpopulation (1-6 Log reduction), the optimized hydrogel is able to disrupt the preformed bacterial biofilm and even kill the biofilm-trapped pathogens with enhanced pathogenicity. Above all, the lead hydrogel was proficient in tackling methicillin-resistant Staphylococcus aureus (MRSA) wound infections in a mouse model through its safe topical administration. Overall, the biocide-loaded hydrogel can be considered as a promising candidate to combat MDR chronic infections at the wound site.}, } @article {pmid36541661, year = {2023}, author = {Pham, QN and Winter, M and Milanova, V and Young, C and Condina, MR and Hoffmann, P and Pham, NTH and Tung, TT and Losic, D and Thierry, B}, title = {Magnetic enrichment of immuno-specific extracellular vesicles for mass spectrometry using biofilm-derived iron oxide nanowires.}, journal = {Nanoscale}, volume = {15}, number = {3}, pages = {1236-1247}, doi = {10.1039/d2nr05619d}, pmid = {36541661}, issn = {2040-3372}, mesh = {Female ; Pregnancy ; Humans ; Chromatography, Liquid/methods ; Proteomics/methods ; *Nanowires ; Reproducibility of Results ; Tandem Mass Spectrometry ; Placenta ; *Extracellular Vesicles/chemistry ; Proteins/analysis ; }, abstract = {Immuno-specific enrichment of extracellular vesicles (EVs) can provide important information into cellular pathways underpinning various pathologies and for non-invasive diagnostics, including mass spectrometry-based analyses. Herein, we report an optimised protocol for immuno-magnetic enrichment of specific EV subtypes and their subsequent processing with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Specifically, we conjugated placental alkaline phosphatase (PLAP) antibodies to magnetic iron oxide nanowires (NWs) derived from bacterial biofilms and demonstrated the utility of this approach by enriching placenta-specific EVs (containing PLAP) from cell culture media. We demonstrate efficient PLAP+ve EV enrichment for both NW-PLAP and Dynabeads™-PLAP, with high PLAP protein recovery (83.7 ± 8.9% and 83.2 ± 5.9%, respectively), high particle-to-protein ratio (7.5 ± 0.7 × 10[9] and 7.1 ± 1.2 × 10[9], respectively), and low non-specific binding of non-target EVs (7 ± 3.2% and 5.4 ± 2.2%, respectively). Furthermore, our optimized EV enrichment and processing approach identified 2518 and 2545 protein groups with LC-MS/MS for NW-PLAP and Dynabead™-PLAP, respectively, with excellent reproducibility (Pearson correlation 0.986 and 0.988). These findings demonstrate that naturally occurring iron oxide NWs have comparable performance to current gold standard immune-magnetic beads. The optimized immuno-specific EV enrichment for LC-MS/MS method provides a low-cost and highly-scalable yet efficient, high-throughput approach for quality EV proteomic studies.}, } @article {pmid36539472, year = {2022}, author = {Zeng, J and Chen, D and Lv, C and Qin, K and Zhou, Q and Pu, N and Song, S and Wang, X}, title = {Antimicrobial and anti-biofilm activity of Polygonum chinense L.aqueous extract against Staphylococcus aureus.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {21988}, pmid = {36539472}, issn = {2045-2322}, mesh = {Humans ; Staphylococcus aureus ; *Polygonum ; *Anti-Infective Agents/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Staphylococcal Infections/microbiology ; Microbial Sensitivity Tests ; }, abstract = {Polygonum chinense Linn. (Polygonum chinense L.) is one of the main raw materials of Chinese patent medicines such as Guangdong herbal tea. The increasing antibiotic resistance of S. aureus and the biofilm poses a serious health threat to humans, and there is an urgent need to provide new antimicrobial agents. As a traditional Chinese medicine, the antibacterial effect of Polygonum chinense L. has been reported, but the antibacterial mechanism of Polygonum chinense L.aqueous extract and its effect on biofilm have not been studied in great detail, which hinders its application as an effective antibacterial agent. In this study, the mechanism of action of Polygonum chinense L.aqueous extract on Staphylococcus aureus (S. aureus) and its biofilm was mainly evaluated by morphological observation, flow cytometry and laser confocal experiments. Our findings demonstrate that Polygonum chinense L.aqueous extract has a significant bacteriostatic effect on S. aureus. The result of growth curve exhibits that Polygonum chinense L.aqueous extract presents a significant inhibitory effect against S. aureus. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) reveals that Polygonum chinense L.aqueous extract exerts a potent destruction of the cell wall of S. aureus and a significant inhibitory effect on the formation of S. aureus biofilm. In addition, flow cytometry showed the ability of Polygonum chinense L.aqueous extract to promote apoptosis by disrupting cell membranes of S. aureus. Notably, confocal laser scanning microscopy (CLSM) images illustrated the ability of Polygonum chinense L.aqueous to inhibit the formation of S. aureus biofilms in a dose-dependent manner. These results suggested that Polygonum chinense L.aqueous is a promising alternative antibacterial and anti-biofilm agent for combating infections caused by planktonic and biofilm cells of S. aureus.}, } @article {pmid36538964, year = {2023}, author = {Cao, L and Ni, L and Qi, L and Wen, H and Wang, Z and Meng, J and Zhang, X and Zhang, Y}, title = {The application of post-denitrification fixed biofilm reactor for polishing secondary effluent: Nitrate removal, soluble microbial products and micropollutants biotransformation.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128511}, doi = {10.1016/j.biortech.2022.128511}, pmid = {36538964}, issn = {1873-2976}, mesh = {*Wastewater ; *Nitrates/analysis ; Denitrification ; Bioreactors ; Biotransformation ; Biofilms ; Nitrogen/analysis ; }, abstract = {This study was conducted to comprehensively evaluate the role of hydraulic retention time (HRT) on simultaneous removal of nitrate and micropollutants (MPs) in secondary effluent from wastewater treatment plants in post-denitrification fixed biofilm reactor (PDFBR). Results showed that PDFBR was favorable for nitrate removal (above 94%). Prolonged HRT promoted the bio-utilization of nonaromatic soluble microbial products with low molecular weight and reduced biomass production. MPs was partially removed in PDFBRs (below 48%). Microbial diversity increased along the extending of HRT and thus partially enhanced MPs removal. Batch experiments showed that changing HRT had no direct impact on the biodegradation rates of the selected MPs. Correlation analysis revealed that Dechloromonas, Terrimonas, and Phreatobacter were reasonable for simultaneous removal of MPs and nitrate. The abundance of nosZ gene had a rapid decrease under extreme HRT. This study provides insights into polishing nitrate and MPs from secondary effluent in a denitrifying biofilm system.}, } @article {pmid36538963, year = {2023}, author = {Luan, YN and Yin, Y and Xu, Y and Zhang, F and Wang, X and Zhao, F and Xiao, Y and Liu, C}, title = {Simultaneous nitrification and denitrification in a novel rotating self-aerated biofilm reactor for decentralized wastewater treatment.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128513}, doi = {10.1016/j.biortech.2022.128513}, pmid = {36538963}, issn = {1873-2976}, mesh = {*Nitrification ; *Denitrification ; Bioreactors/microbiology ; Biofilms ; Nitrogen/metabolism ; Waste Disposal, Fluid ; }, abstract = {Decentralized wastewater pollution in rural areas has become a serious problem for the rural environment. In this study, a novel rotating self-aerated biofilm reactor was developed for decentralized wastewater treatment without any aeration equipment. After the long-term operation of 110 days, the removal efficiency reached to 96.06 % (COD), 98.06 % (NH4[+]-N), and 62.58 % (TN) in the last phase. Under high dissolved oxygen level, the simultaneous nitrification-denitrification (SND) maintained at a stable ratio of 62.53 % and the denitrification rates reached over 28.37 mg/L/h. With the organic loading rate increased, key nitrogen functional bacterial communities such as anoxic denitrifiers (Thiothrix, Flavobacterium, Pseudoxanthomonas, Aquimonas and Azoarcus) and aerobic denitrifiers (Hydrogenophaga, Zoogloea and Terrimonas) increased obviously. Overall, microbial analysis and nitrogen metabolism pathway indicated that an integration of SND process was achieved in this single reactor by the combined action of nitrification, denitrification and comammox without any aeration equipment.}, } @article {pmid36538956, year = {2023}, author = {Cheng, P and Zhang, Y and Ma, N and Wang, L and Jiang, L and Fang, Z and Wang, Y and Tan, X}, title = {The parallel electron transfer pathways of biofilm and self-secreted electron shuttles in gram-positive strain Rhodococcus pyridinivorans HR-1 inoculated microbial fuel cell.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128514}, doi = {10.1016/j.biortech.2022.128514}, pmid = {36538956}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Electrons ; Electricity ; Biofilms ; Electrodes ; }, abstract = {Microbial fuel cell (MFC) exhibits huge potentials in disposing wastewater and extra energy consumption. Exploring useful microorganisms for MFC is the crucial section. Herein, the electrochemical mechanism of extracellular anaerobic respiration in MFC inoculated with gram-positive Rhodococcus pyridinivorans HR-1, was first revealed. The MFC exhibited rapid recovery of currents on anode, and could recover to maximum output within one hour, with redox peaks near -0.38 and -0.18 V through electron transfer between the biofilm and anode. When the biofilm-based pathway was blocked by wrapping the anode with Millipore filter membrane, HR-1 inoculated MFC could still generate electricity within a longer recovery period (∼35 h) during anolyte exchange. This was proposed as a self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1. Cyclic voltammetry analysis revealed that the biofilm-based and self-secreted electron shuttle-based pathways co-existed in R. pyridinivorans HR-1 inoculated MFC, which could play synergistic roles in electricity generation.}, } @article {pmid36537821, year = {2023}, author = {Gonçalves, ASC and Leitão, MM and Simões, M and Borges, A}, title = {The action of phytochemicals in biofilm control.}, journal = {Natural product reports}, volume = {40}, number = {3}, pages = {595-627}, doi = {10.1039/d2np00053a}, pmid = {36537821}, issn = {1460-4752}, mesh = {*Biofilms ; *Anti-Bacterial Agents/pharmacology/chemistry ; Quorum Sensing ; Bacteria/metabolism ; Phytochemicals/chemistry ; }, abstract = {Covering: 2009 to 2021Antimicrobial resistance is now rising to dangerously high levels in all parts of the world, threatening the treatment of an ever-increasing range of infectious diseases. This has becoming a serious public health problem, especially due to the emergence of multidrug-resistance among clinically important bacterial species and their ability to form biofilms. In addition, current anti-infective therapies have low efficacy in the treatment of biofilm-related infections, leading to recurrence, chronicity, and increased morbidity and mortality. Therefore, it is necessary to search for innovative strategies/antibacterial agents capable of overcoming the limitations of conventional antibiotics. Natural compounds, in particular those obtained from plants, have been exhibiting promising properties in this field. Plant secondary metabolites (phytochemicals) can act as antibiofilm agents through different mechanisms of action from the available antibiotics (inhibition of quorum-sensing, motility, adhesion, and reactive oxygen species production, among others). The combination of different phytochemicals and antibiotics have revealed synergistic or additive effects in biofilm control. This review aims to bring together the most relevant reports on the antibiofilm properties of phytochemicals, as well as insights into their structure and mechanistic action against bacterial pathogens, spanning December 2008 to December 2021.}, } @article {pmid36536809, year = {2022}, author = {Kumari, M and Bhattarai, NR and Rai, K and Pandit, TK and Khanal, B}, title = {Multidrug-Resistant Acinetobacter: Detection of ESBL, MBL, bla NDM-1 Genotype, and Biofilm Formation at a Tertiary Care Hospital in Eastern Nepal.}, journal = {International journal of microbiology}, volume = {2022}, number = {}, pages = {8168000}, pmid = {36536809}, issn = {1687-918X}, abstract = {BACKGROUND: The Acinetobacter species is an important hospital-acquired pathogen. The rapid development of resistance to multiple drugs and the ability to form biofilm make these bacteria more adaptable to survive in healthcare facilities, thus posing a challenge to their effective management.

OBJECTIVE: This study aimed to characterize clinical isolates of Acinetobacter spp and to study their antimicrobial susceptibility patterns and ability to form biofilm. Resistant Acinetobacter was further analyzed for the detection of extended-spectrum β-lactamases (ESBLs), metallo β-lactamases (MBLs), carbapenemase production, and presence of blaNDM-1 gene.

MATERIALS AND METHODS: A total of 324 Acinetobacter species were isolated from various clinical specimens which were submitted to the Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal, and were studied for antibiotic susceptibility testing, detection of ESBL and MBL production, and formerly biofilm formation was performed by standard microbiological methods. PCR was carried out to determine the presence of the blaNDM-1 gene.

RESULTS: The predominant Acinetobacter species isolated was A calcoaceticus-baumannii Complex (Acb complex) 167 (51.5%). Among those, all A. species 128 (40%) were multidrug resistant (MDR). In which 13 (4.0%) were ESBL producers, 70 (61.9%) were MBL, and 12 (10.6%) were carbapenemases producers. The blaNDM1 gene was present in 33 isolates. Thirty-seven percent (121/324) of isolates formed biofilm. The majority of A. species were resistant to cefotaxime 73.8% (239) and cefepime 74.4% (241). A significant proportion of biofilm producers were MDR (p < 0.001).

CONCLUSION: Drug-resistant Acinetobacter formed a substantial proportion of this hospital's samples with a large presence of the bla NDM-1 gene. A matter of great concern is the association of multidrug-resistant phenotype with biofilm formation. This situation warranted stringent surveillance and adherence to infection prevention and control practices.}, } @article {pmid36536030, year = {2022}, author = {Haddadian, A and Robattorki, FF and Dibah, H and Soheili, A and Ghanbarzadeh, E and Sartipnia, N and Hajrasouliha, S and Pasban, K and Andalibi, R and Ch, MH and Azari, A and Chitgarzadeh, A and Kashtali, AB and Mastali, F and Noorbazargan, H and Mirzaie, A}, title = {Niosomes-loaded selenium nanoparticles as a new approach for enhanced antibacterial, anti-biofilm, and anticancer activities.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {21938}, pmid = {36536030}, issn = {2045-2322}, mesh = {Humans ; Female ; Liposomes ; *Selenium/chemistry ; Anti-Bacterial Agents ; *Nanoparticles ; *Breast Neoplasms ; }, abstract = {Targeted drug delivery and increasing the biological activity of drugs is one of the recent challenges of pharmaceutical researchers. Niosomes are one of the new targeted drug delivery systems that enhances the biological properties of drugs. In this study, for the first time, the green synthesis of selenium nanoparticles (SeNPs), and its loading into niosome was carried out to increase the anti-bacterial and anti-cancer activity of SeNPs. Different formulations of noisome-loaded SeNPs were prepared, and the physical and chemical characteristics of the prepared niosomes were investigated. The antibacterial and anti-biofilm effects of synthesized niosomes loaded SeNPs and free SeNPs against standard pathogenic bacterial strains were studied, and also its anticancer activity was investigated against breast cancer cell lines. The expression level of apoptotic genes in breast cancer cell lines treated with niosome-loaded SeNPs and free SeNPs was measured. Also, to evaluate the biocompatibility of the synthesized niosomes, their cytotoxicity effects against the human foreskin fibroblasts normal cell line (HFF) were studied using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results illustrated that the optimal formulation had an average size of 177.9 nm, a spherical shape, and an encapsulation efficiency of 37.58%. Also, the results revealed that the release rate of SeNPs from niosome-loaded SeNPs and free SeNPs was 61.26% and 100%, respectively, in 72 h. Also, our findings demonstrated that the niosome-loaded SeNPs have significant antibacterial, anti-biofilm, and anticancer effects compared to the free SeNPs. In addition, niosome-loaded SeNPs can upregulate the expression level of Bax, cas3, and cas9 apoptosis genes while the expression of the Bcl2 gene is down-regulated in all studied cell lines, significantly. Also, the results of the MTT test indicated that the free niosome has no significant cytotoxic effects against the HFF cell line which represents the biocompatibility of the synthesized niosomes. In general, based on the results of this study, it can be concluded that niosomes-loaded SeNPs have significant anti-microbial, anti-biofilm, and anti-cancer effects, which can be used as a suitable drug delivery system.}, } @article {pmid36535943, year = {2022}, author = {Carda-Diéguez, M and Rosier, BT and Lloret, S and Llena, C and Mira, A}, title = {The tongue biofilm metatranscriptome identifies metabolic pathways associated with the presence or absence of halitosis.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {100}, pmid = {36535943}, issn = {2055-5008}, mesh = {Humans ; *Hydrogen Sulfide/metabolism ; *Halitosis/metabolism/microbiology ; Tongue/microbiology ; Sulfhydryl Compounds/metabolism ; Biofilms ; Metabolic Networks and Pathways ; }, abstract = {Intra-oral halitosis usually results from the production of volatile sulfur compounds, such as methyl mercaptan and hydrogen sulfide, by the tongue microbiota. There are currently no reports on the microbial gene-expression profiles of the tongue microbiota in halitosis. In this study, we performed RNAseq of tongue coating samples from individuals with and without halitosis. The activity of Streptococcus (including S. parasanguinis), Veillonella (including V. dispar) and Rothia (including R. mucilaginosa) was associated with halitosis-free individuals while Prevotella (including P. shahi), Fusobacterium (including F. nucleatum) and Leptotrichia were associated with halitosis. Interestingly, the metatranscriptome of patients that only had halitosis levels of methyl mercaptan was similar to that of halitosis-free individuals. Finally, gene expression profiles showed a significant over-expression of genes involved in L-cysteine and L-homocysteine synthesis, as well as nitrate reduction genes, in halitosis-free individuals and an over-expression of genes responsible for cysteine degradation into hydrogen sulfide in halitosis patients.}, } @article {pmid36535619, year = {2023}, author = {Rai, LS and Chauvel, M and Permal, E and d'Enfert, C and Bachellier-Bassi, S}, title = {Transcript profiling reveals the role of PDB1, a subunit of the pyruvate dehydrogenase complex, in Candida albicans biofilm formation.}, journal = {Research in microbiology}, volume = {174}, number = {3}, pages = {104014}, doi = {10.1016/j.resmic.2022.104014}, pmid = {36535619}, issn = {1769-7123}, mesh = {Humans ; *Candida albicans/metabolism ; *Pyruvate Dehydrogenase Complex/genetics/metabolism ; Antifungal Agents/metabolism ; Transcriptome ; Biofilms ; }, abstract = {Candida albicans, the most prevalent fungal pathogen in the human microbiota can form biofilms on implanted medical devices. These biofilms are tolerant to conventional antifungal drugs and the host immune system as compared to the free-floating planktonic cells. Several in vitro models of biofilm formation have been used to determine the C. albicans biofilm-forming process, regulatory networks, and their properties. Here, we performed a genome-wide transcript profiling with C. albicans cells grown in YPD medium both in planktonic and biofilm condition. Transcript profiling of YPD-grown biofilms was further compared with published Spider medium-grown biofilm transcriptome data. This comparative analysis highlighted the differentially expressed genes and the pathways altered during biofilm formation. In addition, we demonstrated that overexpression of the PDB1 gene encoding a subunit of the pyruvate dehydrogenase resulted in defective biofilm formation. Altogether, this comparative analysis of transcript profiles from two different studies provides a robust reading on biofilm-altered genes and pathways during C. albicans biofilm development.}, } @article {pmid36535428, year = {2023}, author = {Milton, ME and Cavanagh, J}, title = {The Biofilm Regulatory Network from Bacillus subtilis: A Structure-Function Analysis.}, journal = {Journal of molecular biology}, volume = {435}, number = {3}, pages = {167923}, doi = {10.1016/j.jmb.2022.167923}, pmid = {36535428}, issn = {1089-8638}, mesh = {*Bacillus subtilis/genetics/physiology ; *Bacterial Proteins/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Transcription Factors/metabolism ; }, abstract = {Bacterial biofilms are notorious for their ability to protect bacteria from environmental challenges, most importantly the action of antibiotics. Bacillus subtilis is an extensively studied model organism used to understand the process of biofilm formation. A complex network of principal regulatory proteins including Spo0A, AbrB, AbbA, Abh, SinR, SinI, SlrR, and RemA, work in concert to transition B. subtilis from the free-swimming planktonic state to the biofilm state. In this review, we explore, connect, and summarize decades worth of structural and biochemical studies that have elucidated this protein signaling network. Since structure dictates function, unraveling aspects of protein molecular mechanisms will allow us to devise ways to exploit critical features of the biofilm regulatory pathway, such as possible therapeutic intervention. This review pools our current knowledge base of B. subtilis biofilm regulatory proteins and highlights potential therapeutic intervention points.}, } @article {pmid36534660, year = {2022}, author = {Young, MM and de Oliveira, AL and Nolan, LK and Barbieri, NL and Logue, CM}, title = {Identification of novel genes involved in the biofilm formation process of Avian Pathogenic Escherichia coli (APEC).}, journal = {PloS one}, volume = {17}, number = {12}, pages = {e0279206}, pmid = {36534660}, issn = {1932-6203}, mesh = {Animals ; Escherichia coli/genetics ; *Escherichia coli Proteins/genetics ; Virulence/genetics ; Chickens/genetics ; *Escherichia coli Infections/epidemiology ; Virulence Factors/genetics ; Biofilms ; Real-Time Polymerase Chain Reaction ; *Poultry Diseases/epidemiology ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is the etiological agent of avian colibacillosis, a leading cause of economic loss to the poultry industry worldwide. APEC causes disease using a diverse repertoire of virulence factors and has the ability to form biofilms, which contributes to the survival and persistence of APEC in harsh environments. The objective of this study was to identify genes most widespread and important in APEC that contribute to APEC biofilm formation. Using the characterized APEC O18 as the template strain, a total of 15,660 mutants were randomly generated using signature tagged mutagenesis and evaluated for decreased biofilm formation ability using the crystal violet assay. Biofilm deficient mutants were sequenced, and a total of 547 putative biofilm formation genes were identified. Thirty of these genes were analyzed by PCR for prevalence among 109 APEC isolates and 104 avian fecal E. coli (AFEC) isolates, resulting in nine genes with significantly greater prevalence in APEC than AFEC. The expression of these genes was evaluated in the wild-type APEC O18 strain using quantitative real-time PCR (qPCR) in both the exponential growth phase and the mature biofilm phase. To investigate the role of these genes in biofilm formation, isogenic mutants were constructed and evaluated for their biofilm production and planktonic growth abilities. Four of the mutants (rfaY, rfaI, and two uncharacterized genes) displayed significantly decreased biofilm formation, and of those four, one (rfaI) displayed significantly decreased growth compared to the wild type. Overall, this study identified novel genes that may be important in APEC and its biofilm formation. The data generated from this study will benefit further investigation into the mechanisms of APEC biofilm formation.}, } @article {pmid36534183, year = {2022}, author = {Amirinejad, N and Shahriary, P and Hassanshahian, M}, title = {Investigation of the synergistic effect of glycolipid biosurfactant produced by Shewanella algae with some antibiotics against planktonic and biofilm forms of MRSA and antibiotic resistant Acinetobacter baumannii.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {2}, pages = {45}, pmid = {36534183}, issn = {1573-0972}, mesh = {Anti-Bacterial Agents/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; *Acinetobacter baumannii ; Plankton ; *Anti-Infective Agents/pharmacology ; Ciprofloxacin/pharmacology ; Biofilms ; Gentamicins/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {To tackling antibiotic resistance and the appearance of multidrug-resistant (MDR) strains, one current approach is the combined use of biosurfactants with antibiotics to increase their efficacy. The antimicrobial ability of biosurfactant produced by Shewanella algae strain B12 was examined using the agar well diffusion method versus some resistant Gram-negative and Gram-positive bacteria. The Minimum Inhibitory Concentration (MIC) of Glycolipid-Biosurfactant of B12 (GBB12) was performed by the broth dilution technique. The inhibition of biofilm formation, disruption of biofilm, and reducing the population of viable cells in biofilm were evaluated by the microtiter plate method. Finally, Scanning Electron Microscopy (SEM) analysis was used to confirm the disruption of the cell membrane by GBB12. In all experiments, when GBB12 was added to antibiotics (except Amikacin), the antimicrobial activity was increased. The synergistic effects of GBB12 and antibiotics (Ciprofloxacin and Gentamycin) against Methicillin-Resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii were confirmed by the Fractional Inhibitory Concentration Index (FICI). GBB12-Gentamycin mixture almost completely inhibits the formation of A. baumannii biofilm, reaching 99.8% inhibition. Also, the rate of MRSA biofilm inhibition treated with GBB12-Ciprofloxacin mixture was found to be 99.4%. biosurfactant-antibiotic mixture could be adequate replacements for traditional antibiotics in the near future. This study shows the potential of GBB12 as antimicrobial and antibiofilm agent.}, } @article {pmid36532539, year = {2022}, author = {Xiong, R and Yan, J and Mei, J and Ye, J and Xie, J}, title = {The enhanced expression of genes encoding diguanylate cyclases under cold stress contributes to the adhesion and biofilm formation of Shewanella putrefaciens WS13.}, journal = {Frontiers in nutrition}, volume = {9}, number = {}, pages = {1076932}, pmid = {36532539}, issn = {2296-861X}, abstract = {Shewanella putrefaciens is a special spoilage bacterium of seafood during cold storage, which is easy to form biofilm and bring serious hazard to the seafood quality. Life cycle of biofilm starts after bacterial adhesion, which is essential for the formation and development of biofilm. As a ubiquitous second messenger in bacteria, c-di-GMP regulates the conversion between bacterial planktonic state and biofilm state. In this study, the adhesion and biofilm formation of S. putrefaciens WS13 under 4°C were compared to those under 30°C. Atom force microscope and scanning electron microscope were used to study the bacterial adhesion. Biofilm was analyzed by Fourier transform infrared spectroscopy, Bradford assay and phenol-sulfuric acid method. High-performance liquid chromatographic-tandem mass spectrometric and quantitative real-time PCR were applied to study c-di-GMP level and genes encoding diguanylate cyclases in cells, respectively. Results showed that the swarming mobility of S. putrefaciens WS13 was weaker under 4°C, however, the adhesive force under 4°C was 4-5 times higher than that under 30°C. Biofilm biomass, extracellular polysaccharides and extracellular proteins were 2.5 times, 3 times, and 1.6 times more than those under 30°C, respectively, but biofilm composition formed under both temperatures were similar. c-di-GMP level in S. putrefaciens WS13 under 30°C was no more than half of that in the corresponding growth stage under 4°C. Quantitative real-time PCR analysis also showed that the expression of genes encoding diguanylate cyclases were significantly enhanced under 4°C than that under 30°C. S. putrefaciens WS13 adapted to the cold stress by enhancing the expression of genes encoding diguanylate cyclases to promote bacterial adhesion and biofilm formation. This study provides a theoretical foundation for the research on the cold adaptation mechanism of specific spoilage bacteria of seafood based on c-di-GMP, and also provides a new idea to control seafood quality from the perspective of microbial molecular biology.}, } @article {pmid36532477, year = {2022}, author = {Avila-Novoa, MG and Solis-Velazquez, OA and Guerrero-Medina, PJ and González-Gómez, JP and González-Torres, B and Velázquez-Suárez, NY and Martínez-Chávez, L and Martínez-Gonzáles, NE and De la Cruz-Color, L and Ibarra-Velázquez, LM and Cardona-López, MA and Robles-García, MÁ and Gutiérrez-Lomelí, M}, title = {Genetic and compositional analysis of biofilm formed by Staphylococcus aureus isolated from food contact surfaces.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1001700}, pmid = {36532477}, issn = {1664-302X}, abstract = {INTRODUCTION: Staphylococcus aureus is an important pathogen that can form biofilms on food contact surfaces (FCS) in the dairy industry, posing a serious food safety, and quality concern. Biofilm is a complex system, influenced by nutritional-related factors that regulate the synthesis of the components of the biofilm matrix. This study determines the prevalence of biofilm-associated genes and evaluates the development under different growth conditions and compositions of biofilms produced by S. aureus.

METHODS: Biofilms were developed in TSB, TSBG, TSBNaCl, and TSBGNaCl on stainless-steel (SS), with enumeration at 24 and 192 h visualized by epifluorescence and scanning electron microscopy (SEM). The composition of biofilms was determined using enzymatic and chemical treatments and confocal laser scanning microscopy (CLSM).

RESULTS AND DISCUSSION: A total of 84 S. aureus (SA1-SA84) strains were collected from 293 dairy industry FCS (FCS-stainless steel [n = 183] and FCS-polypropylene [n = 110]) for this study. The isolates harbored the genes sigB (66%), sar (53%), agrD (52%), clfB/clfA (38%), fnbA/fnbB (20%), and bap (9.5%). 99. In particular, the biofilm formed by bap-positive S. aureus onto SS showed a high cell density in all culture media at 192 h in comparison with the biofilms formed at 24 h (p < 0.05). Epifluorescence microscopy and SEM revealed the metabolically active cells and the different stages of biofilm formation. CLSM analysis detected extracellular polymeric of S. aureus biofilms on SS, such as eDNA, proteins, and polysaccharides. Finally, the level of detachment on being treated with DNase I (44.7%) and NaIO 4(42.4%) was greater in the biofilms developed in TSB compared to culture medium supplemented with NaCl at 24 h; however, there was no significant difference when the culture medium was supplemented with glucose. In addition, after treatment with proteinase K, there was a lower level of biomass detachment (17.7%) of the biofilm developed in TSBNaCl (p < 0.05 at 24 h) compared to that in TSB, TSBG, and TSBGNaCl (33.6, 36.9, and 37.8%, respectively). These results represent a deep insight into the composition of S. aureus biofilms present in the dairy industry, which promotes the development of more efficient composition-specific disinfection strategies.}, } @article {pmid36532326, year = {2022}, author = {Chhaliyil, P and Fischer, KF and Schoel, B and Chhalliyil, P}, title = {Impact of Refined and Unrefined Sugar and Starch on the Microbiota in Dental Biofilm.}, journal = {Journal of International Society of Preventive & Community Dentistry}, volume = {12}, number = {5}, pages = {554-563}, pmid = {36532326}, issn = {2231-0762}, abstract = {AIMS AND OBJECTIVE: Sugar is not only associated with dental diseases but also, along with carbohydrates, is linked to various health issues including obesity, cancer, diabetes, heart, liver, and kidney-related diseases. At the same time, a polyphenol present in unrefined sugar and starch (UReSS) is shown to inhibit microbial growth and prevent biofilms and dental plaque. The question arises, "is sugar the causative agent for dental diseases, or is its refined form the cause?" The objective of this study is to conduct in-vivo studies of the impact of refined and unrefined sugar and starch on the microbiota of dental biofilm.

MATERIALS AND METHODS: An in-vivo study was performed using saliva and dental biofilm samples collected from 75 healthy subjects. For this study, healthy volunteers (n = 75) were randomly divided into five groups and were given sweet meals either made with refined white sugar and white rice (ReSS) or with unrefined brown sugar and red rice (UReSS). This was followed by using or not using a polyphenolic mouthwash. Before and after 4 h of eating a sweet meal, the saliva and dental plaque were collected and the DNA was analyzed by 16s metagenomic sequencing. The results were expressed in fold change of bacteria from 0 to 4 h. Statistical analyses have been performed by logarithmic linear discriminant analysis (LDA), Student's t-test, and Wilcoxon signed-rank test.

RESULTS: Upon LEfSe and statistical analysis, in-vivo experiments clearly showed that UReSS significantly decreased bacteria associated with dental diseases. In contrast, ReSS showed a significant increase in Actinomyces, Streptococcus, and Selenomonas with a high LDA score (Log 4.2) and statistical significance (P < 0.003). Mouthwash significantly decreased bacterial taxa associated with diseases in both the ReSS and UReSS groups. The in-vivo study showed a significant increase and decrease in Streptococcus levels in refined and unrefined sugar groups, respectively.

CONCLUSION: In conclusion, polyphenols aid in the prevention of dental caries. This study recommends using polyphenol-rich unrefined sugars and carbohydrates for both oral and general health. This study is the first of its kind to bring awareness to the effects of refined and unrefined starch and sugars on the oral microbiota.}, } @article {pmid36529875, year = {2022}, author = {Pottker, ES and Rodrigues, LB and Borges, KA and de Souza, SO and Furian, TQ and Pippi Salle, CT and de Souza Moraes, HL and do Nascimento, VP}, title = {Bacteriophages as an alternative for biological control of biofilm-forming Salmonella enterica.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {}, number = {}, pages = {10820132221144341}, doi = {10.1177/10820132221144341}, pmid = {36529875}, issn = {1532-1738}, abstract = {Salmonellosis is one of the most common foodborne diseases worldwide. Surface adherence and biofilm formation are among the main strategies evolved by Salmonella to survive under harsh conditions and are risk factors for its spread through the food chain. Owing to the increase in antimicrobial resistance, there is a growing need to develop other methods to control foodborne pathogens, and bacteriophages have been suggested as a potential alternative for this purpose. The aim of this study was to evaluate bacteriophages as a biological control of Salmonella enterica serotypes to inhibit and remove bacterial biofilms. A total of 12 S. enterica isolates were selected for this study, all of which were biofilm producers. Seven bacteriophages were tested, individually and in a cocktail, for their host range and efficiency of plating (EOP). The phage cocktail was evaluated for its antibiofilm effect against the Salmonella biofilms. Phages UPF_BP1, UPF_BP2, UPF_BP3, UPF_BP6, and 10:2 possessed a broad lytic spectrum and could infect all S. enterica strains. Phages 10:2, UPF_BP6, and UPF_BP3 had high EOP in 10, 9, and 9 out of the 12 S. enterica strains, respectively. The cocktail was able to infect all S. enterica strains and had a high EOP in 10 out of 12 S. enterica isolates, presenting a broader host range than any of the tested single phages. A wide variation of inhibition among strains was observed, ranging from 14.72% to 88.53%. Multidrug-resistant and strong biofilm producer strains showed high biofilm inhibition levels by phage cocktail. Our findings demonstrate the ability of the cocktail to prevent biofilm formation and remove formed biofilms of Salmonella. These results indicate that the phage cocktail is a promising candidate to be used as an alternative for the control of Salmonella biofilms through surface conditioning.}, } @article {pmid36528648, year = {2022}, author = {Cárdenas-Calderón, C and Veloso-Giménez, V and González, T and Wozniak, A and García, P and Martín, SS and Varas, JF and Carrasco-Wong, I and Vera, M and Egaña, JT}, title = {Development of an implantable three-dimensional model of a functional pathogenic multispecies biofilm to study infected wounds.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {21846}, pmid = {36528648}, issn = {2045-2322}, mesh = {Mice ; Animals ; *Pseudomonas Infections/microbiology ; *Wound Infection/microbiology ; Biofilms ; Pseudomonas aeruginosa ; Staphylococcus aureus/physiology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Chronic wounds cannot heal due to impairment of regeneration, mainly caused by the persistent infection of multispecies biofilms. Still, the effects of biofilm wound infection and its interaction with the host are not fully described. We aimed to study functional biofilms in physiological conditions in vitro, and their potential effects in health and regeneration in vivo. Therefore, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis were seeded in collagen-based scaffolds for dermal regeneration. After 24 h, scaffolds had bacterial loads depending on the initial inoculum, containing viable biofilms with antibiotic tolerance. Afterwards, scaffolds were implanted onto full skin wounds in mice, together with daily supervision and antibiotic treatment. Although all mice survived their health was affected, displaying fever and weight loss. After ten days, histomorphology of scaffolds showed high heterogeneity in samples and within groups. Wounds were strongly, mildly, or not infected according to colony forming units, and P. aeruginosa had higher identification frequency. Biofilm infection induced leucocyte infiltration and elevated interferon-γ and interleukin-10 in scaffolds, increase of size and weight of spleen and high systemic pro-calcitonin concentrations. This functional and implantable 3D biofilm model allows to study host response during infection, providing a useful tool for infected wounds therapy development.}, } @article {pmid36528619, year = {2022}, author = {Morris, RJ and Stevenson, D and Sukhodub, T and Stanley-Wall, NR and MacPhee, CE}, title = {Density and temperature controlled fluid extraction in a bacterial biofilm is determined by poly-γ-glutamic acid production.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {98}, pmid = {36528619}, issn = {2055-5008}, support = {/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/genetics ; Biofilms ; *Glutamic Acid/metabolism ; Temperature ; }, abstract = {A hallmark of microbial biofilms is the self-production of an extracellular molecular matrix that encases the resident cells. The matrix provides protection from the environment, while spatial heterogeneity of gene expression influences the structural morphology and colony spreading dynamics. Bacillus subtilis is a model bacterial system used to uncover the regulatory pathways and key building blocks required for biofilm growth and development. In this work, we report on the emergence of a highly active population of bacteria during the early stages of biofilm formation, facilitated by the extraction of fluid from the underlying agar substrate. We trace the origin of this fluid extraction to the production of poly-γ-glutamic acid (PGA). The flagella-dependent activity develops behind a moving front of fluid that propagates from the boundary of the biofilm towards the interior. The extent of fluid proliferation is controlled by the presence of extracellular polysaccharides (EPS). We also find that PGA production is positively correlated with higher temperatures, resulting in high-temperature mature biofilm morphologies that are distinct from the rugose colony biofilm architecture typically associated with B. subtilis. Although previous reports have suggested that PGA production does not play a major role in biofilm morphology in the undomesticated isolate NCIB 3610, our results suggest that this strain produces distinct biofilm matrices in response to environmental conditions.}, } @article {pmid36528190, year = {2023}, author = {Xiroudaki, S and Sabbatini, S and Pecoraro, C and Cascioferro, S and Diana, P and Wauthoz, N and Antognelli, C and Monari, C and Giovagnoli, S and Schoubben, A}, title = {Development of a new indole derivative dry powder for inhalation for the treatment of biofilm-associated lung infections.}, journal = {International journal of pharmaceutics}, volume = {631}, number = {}, pages = {122492}, doi = {10.1016/j.ijpharm.2022.122492}, pmid = {36528190}, issn = {1873-3476}, mesh = {Powders ; Drug Compounding ; *Chitosan ; *Methicillin-Resistant Staphylococcus aureus ; Administration, Inhalation ; Lung ; Indoles ; Particle Size ; Dry Powder Inhalers ; Aerosols ; }, abstract = {The aim of this work was to produce an inhalable dry powder formulation of a new anti-biofilm compound (SC38). For this purpose, chitosan was used as a polymeric carrier and l-leucine as a dispersibility enhancer. SC38 was entrapped by spray-drying into previously optimized chitosan microparticles. The final formulation was fully characterized in vitro in terms of particle morphology, particle size and distribution, flowability, aerodynamic properties, anti-biofilm activity and effects on lung cell viability. The SC38-loaded chitosan microparticles exhibited favorable aerodynamic properties with emitted and respirable fractions higher than 80 % and 45 % respectively. The optimized formulation successfully inhibited biofilm formation at microparticle concentrations starting from 20 μg/mL for methicillin-sensitive and 100 μg/mL for methicillin-resistant Staphylococcus aureus and showed a relatively safe profile in lung cells after 72 h exposure. Future in vivo tolerability and efficacy studies are needed to unravel the potential of this novel formulation for the treatment of difficult-to-treat biofilm-mediated lung infections.}, } @article {pmid36527964, year = {2023}, author = {He, X and Guo, W and Tang, Y and Xiong, J and Li, Y and Huang, R and Miao, W}, title = {Chloroplast-boosted photodynamic therapy for effective drug-resistant bacteria killing and biofilm ablation.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {238}, number = {}, pages = {112622}, doi = {10.1016/j.jphotobiol.2022.112622}, pmid = {36527964}, issn = {1873-2682}, mesh = {*Photochemotherapy ; Pharmaceutical Preparations ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria ; Chloroplasts ; Biofilms ; Oxygen ; Photosensitizing Agents/pharmacology/therapeutic use ; *Porphyrins ; *Chlorophyllides ; }, abstract = {Due to the misuse of various antibiotics, the problem of bacterial resistance has become more serious worldwide, and the associated diseases have significantly increased the medical burden of society. Antimicrobial photodynamic therapy (PDT) has received widespread attention because of its safety, efficiency, and facile implementation. Here, we report an oxygen-supply antibacterial agent (Ce6@CS/CP), which could enhance the efficacy of antibacterial PDT via photosynthesis of O2. Ce6@CS/CP displayed a robust interaction with bacteria, hence facilitating the delivery efficiency of Ce6. In vitro experiments demonstrated that the photodynamic bactericidal potency of Ce6@CS/CP was remarkably greater than that of free Ce6. Furthermore, Ce6@CS/CP also exhibited superior significant antibiofilm activity to free Ce6. As a live oxygen-supply antibacterial agent, Ce6@CS/CP possesses excellent bacteria delivery ability of Ce6 and could enhance the potency of antibacterial PDT by photosynthesis, offering a new strategy for fighting against drug-resistant bacteria.}, } @article {pmid36527962, year = {2023}, author = {Hemmingsen, LM and Giordani, B and Paulsen, MH and Vanić, Ž and Flaten, GE and Vitali, B and Basnet, P and Bayer, A and Strøm, MB and Škalko-Basnet, N}, title = {Tailored anti-biofilm activity - Liposomal delivery for mimic of small antimicrobial peptide.}, journal = {Biomaterials advances}, volume = {145}, number = {}, pages = {213238}, doi = {10.1016/j.bioadv.2022.213238}, pmid = {36527962}, issn = {2772-9508}, mesh = {Animals ; Mice ; *Antimicrobial Peptides ; Liposomes ; *Anti-Infective Agents/pharmacology ; Staphylococcus aureus/physiology ; Antimicrobial Cationic Peptides/pharmacology ; Biofilms ; }, abstract = {The eradication of bacteria embedded in biofilms is among the most challenging obstacles in the management of chronic wounds. These biofilms are found in most chronic wounds; moreover, the biofilm-embedded bacteria are considerably less susceptible to conventional antimicrobial treatment than the planktonic bacteria. Antimicrobial peptides and their mimics are considered attractive candidates in the pursuit of novel therapeutic options for the treatment of chronic wounds and general bacterial eradication. However, some limitations linked to these membrane-active antimicrobials are making their clinical use challenging. Novel innovative delivery systems addressing these limitations represent a smart solution. We hypothesized that incorporation of a novel synthetic mimic of an antimicrobial peptide in liposomes could improve its anti-biofilm effect as well as the anti-inflammatory activity. The small synthetic mimic of an antimicrobial peptide, 7e-SMAMP, was incorporated into liposomes (~280 nm) tailored for skin wounds and evaluated for its potential activity against both biofilm formation and eradication of pre-formed biofilms. The 7e-SMAMP-liposomes significantly lowered inflammatory response in murine macrophages (~30 % reduction) without affecting the viability of macrophages or keratinocytes. Importantly, the 7e-SMAMP-liposomes completely eradicated biofilms produced by Staphylococcus aureus and Escherichia coli above concentrations of 6.25 μg/mL, whereas in Pseudomonas aeruginosa the eradication reached 75 % at the same concentration. Incorporation of 7e-SMAMP in liposomes improved both the inhibition of biofilm formation as well as biofilm eradication in vitro, as compared to non-formulated antimicrobial, therefore confirming its potential as a novel therapeutic option for bacteria-infected chronic wounds.}, } @article {pmid36526637, year = {2022}, author = {Xu, K and Wang, L and Xiong, D and Chen, H and Tong, X and Shao, X and Li, T and Qian, G}, title = {The Wsp chemosensory system modulates c-di-GMP-dependent biofilm formation by integrating DSF quorum sensing through the WspR-RpfG complex in Lysobacter.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {97}, pmid = {36526637}, issn = {2055-5008}, mesh = {*Lysobacter ; Quorum Sensing ; Antifungal Agents ; Biofilms ; }, abstract = {The ubiquitous Wsp (wrinkly spreader phenotype) chemosensory system and DSF (diffusible signal factor) quorum sensing are two important chemically associated signaling systems that mediate bacterial communications between the host and environment. Although these two systems individually control biofilm formation in pathogenic bacteria via the ubiquitous second messenger c-di-GMP, their crosstalk mechanisms remain elusive. Here we present a scenario from the plant-beneficial and antifungal bacterium Lysobacter enzymogenes OH11, where biofilm formation favors the colonization of this bacterium in fungal hyphae. We found that the Wsp system regulated biofilm formation via WspR-mediated c-di-GMP signaling, whereas DSF system did not depend on the enzymatic activity of RpfG to regulate biofilm formation. We further found that WspR, a diguanylate cyclase (DGC) responsible for c-di-GMP synthesis, could directly bind to one of the DSF signaling components, RpfG, an active phosphodiesterase (PDE) responsible for c-di-GMP degradation. Thus, the WspR-RpfG complex represents a previously undiscovered molecular linker connecting the Wsp and DSF systems. Mechanistically, RpfG could function as an adaptor protein to bind and inhibit the DGC activity of unphosphorylated WspR independent of its PDE activity. Phosphorylation of WspR impaired its binding affinity to RpfG and also blocked the ability of RpfG to act as an adaptor protein, which enabled the Wsp system to regulate biofilm formation in a c-di-GMP-dependent manner by dynamically integrating the DSF system. Our findings demonstrated a previously uncharacterized mechanism of crosstalk between Wsp and DSF systems in plant-beneficial and antifungal bacteria.}, } @article {pmid36526520, year = {2022}, author = {Pedroni, MA and Ribeiro, VST and Cieslinski, J and Lopes, APA and Kraft, L and Suss, PH and Tuon, FF}, title = {Different concentrations of vancomycin with gentamicin loaded PMMA to inhibit biofilm formation of Staphylococcus aureus and their implications.}, journal = {Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jos.2022.11.022}, pmid = {36526520}, issn = {1436-2023}, abstract = {BACKGROUND: This study aimed to evaluate different concentrations of vancomycin and/or gentamicin loaded polymethylmethacrylate (PMMA) against biofilm formation of Staphylococcus aureus.

METHODS: Biofilm production of S. aureus in PMMA loaded with different concentrations of vancomycin and gentamicin were evaluated by quantitative analysis of biofilm cells, scanning electronic microscopy, viability assay, Fourier transform infrared spectroscopy, and checkerboard. Statistical analysis was performed by Mann Whitney test. The difference in colony forming units per mL was significant when p < 0.05.

RESULTS: All loaded PMMA presented a reduction in the number of colony forming units per mL (p < 0.05). The gentamicin-loaded PMMA could inhibits the grown of sessile cells (p < 0.05), where the group vancomycin 4 g + gentamicin 500 mg presented a better result. The Fourier transform infrared spectra showed no significant differences, and checkerboard of vancomycin and gentamicin showed synergism.

CONCLUSION: Effects against adherence and bacterial development in PMMA loaded with antibiotics were mainly seen in the group vancomycin 4 g + gentamicin 500 mg, and synergic effect can be applied in antibiotic-loaded cement.}, } @article {pmid36526458, year = {2023}, author = {Fidelis, CE and de Freitas Leite, R and Garcia, BLN and Gonçalves, JL and Good, L and Dos Santos, MV}, title = {Antimicrobial activities of polyhexamethylene biguanide against biofilm-producing Prototheca bovis causing bovine mastitis.}, journal = {Journal of dairy science}, volume = {106}, number = {2}, pages = {1383-1393}, doi = {10.3168/jds.2022-22468}, pmid = {36526458}, issn = {1525-3198}, mesh = {Cattle ; Female ; Animals ; Sodium Hypochlorite/pharmacology ; Povidone-Iodine ; *Prototheca ; *Mastitis, Bovine ; *Disinfectants/pharmacology ; Biofilms ; *Cattle Diseases ; }, abstract = {Prototheca spp. is a frequent cause of bovine mastitis and is highly resistant to commonly used disinfectants. This study aimed to: (1) evaluate the antimicrobial activity of polyhexamethylene biguanide (PHMB) against mastitis-causing Prototheca spp., and (2) evaluate the biofilm production ability of Prototheca spp. A total of 85 Prototheca bovis and 2 Prototheca blaschkeae isolates from bovine mastitis cases were submitted to biofilm production assays and antimicrobial susceptibility tests against PHMB and disinfectants commonly used in dairy herds (chlorhexidine digluconate, povidone-iodine, sodium dichloroisocyanurate, and sodium hypochlorite). The minimal inhibitory concentration (MIC) and minimal algicidal concentration (MAC) were determined by microdilution assays. We observed that PHMB (MIC90: ≥2 µg/mL and MAC90: ≥4 µg/mL) and chlorhexidine gluconate (MIC90 and MAC90: ≥2 µg/mL) presented the highest antimicrobial activity against P. bovis isolates, followed by sodium dichloroisocyanurate (MIC90 and MAC90: ≥1,400 µg/mL), sodium hypochlorite (MIC90 and MAC90: ≥2,800 µg/mL), and povidone-iodine (MIC90 and MAC90: ≥3,200 µg/mL). Concerning P. blaschkeae isolates, PHMB (MIC and MAC ≥1 µg/mL) and chlorhexidine gluconate (MIC and MAC ≥1 µg/mL) were the disinfectants that presented the lowest concentration values required to inhibit the isolates. Regarding biofilms formation, 63.5% (n = 54/85) of the P. bovis isolates were classified as strong, 28.3% (n = 24/85) moderate, and 8.2% (n = 7/85) weak biofilm producers. In contrast, the P. blaschkeae isolates were classified as weak and moderate biofilm producers. These findings suggest that PHMB has the potential to be used for teat and milking-equipment disinfection for the prevention of mastitis-causing Prototheca spp. in dairy herds.}, } @article {pmid36526040, year = {2023}, author = {Borowicz, M and Krzyżanowska, DM and Jafra, S}, title = {Crystal violet-based assay for the assessment of bacterial biofilm formation in medical tubing.}, journal = {Journal of microbiological methods}, volume = {204}, number = {}, pages = {106656}, doi = {10.1016/j.mimet.2022.106656}, pmid = {36526040}, issn = {1872-8359}, mesh = {*Gentian Violet ; *Staphylococcus aureus ; Biofilms ; Microbial Sensitivity Tests ; Bacteria ; Pseudomonas aeruginosa ; Anti-Bacterial Agents ; }, abstract = {Crystal violet-based assay is widely used to evaluate the early stages of bacterial biofilm formation. Here, we modified it to study biofilm formation in medical tubing. While cost-effective and requiring no sophisticated equipment, our method provided quantitative and qualitative distinctions between the ability of four bacterial strains to colonize PVC catheters.}, } @article {pmid36525873, year = {2023}, author = {Picolo, MZD and Kury, M and Romário-Silva, D and Rosalen, PL and Pecorari, VGA and Gianinni, M and Cavalli, V}, title = {Effects of gastric acid and mechanical toothbrushing in CAD-CAM restorative materials: Mechanical properties, surface topography, and biofilm adhesion.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {138}, number = {}, pages = {105606}, doi = {10.1016/j.jmbbm.2022.105606}, pmid = {36525873}, issn = {1878-0180}, mesh = {Materials Testing ; *Gastric Acid ; *Toothbrushing ; Computer-Aided Design ; Ceramics ; Polymers ; Surface Properties ; Dental Porcelain ; }, abstract = {OBJECTIVE: To evaluate the effects of simulated gastric acid erosion combined with mechanical toothbrushing abrasion on the mechanical properties, surface topography, and biofilm adhesion of different CAD/CAM materials.

MATERIAL AND METHODS: Specimens of zirconia-reinforced lithium silicate glass-ceramic (ZLS), polymer-infiltrated ceramic network (PICN), feldspathic glass-ceramic (FE), and two nanoceramic resins (RK, RG), were submitted to the following challenges: erosion (E), abrasion (A), erosion combined with abrasion (E + A), or remained untreated (control - C). After challenges, flexural strength was evaluated, while microhardness (KHN) and surface roughness (Ra) were tested before and after treatments. The biofilm adhesion (Streptococcus mutans ATCC 700610, Streptococcus sanguinis ATCC 10556 e Candida albicans MYA 2876) was determined by the counting of colonies forming units per milliliters (UFC/mL) after erosive and abrasive challenges.

RESULTS: FE showed the lowest flexural strengths, while ZLS and RG exhibited the highest, while PICN and RK, had intermediate values. PICN, ZLS, and FE showed lower microhardness after E and E + A challenges than polymer-based materials (RG and RK). FE surface roughness increased after E and E + A challenges and after A and E + A challenges for RK. Biofilm formation after erosive/abrasive challenges was higher on ZLS than FE, RK, and RG, but no different than PICN. RK and RG exhibited the lowest biofilm formation among the groups. Furthermore, E + A challenges held significant changes in the surface of the materials, which were more severe on the surface of glass ceramics and hybrid materials.

CONCLUSION: Erosive challenges combined with abrasion negatively influenced the mechanical properties and surface topography of most CAD/CAM materials and increased the biofilm adhesion on ZLS. Besides, the severity of the damage is related to the type and composition of each material.}, } @article {pmid36525156, year = {2023}, author = {Ozdikmenli Tepeli, S and Numanoglu Cevik, Y and Tosun, MN and Taylan Yalcin, G and Kaya, B and Ipek, D and Bakkaloglu, Z and Simsek, H and Zorba, NN}, title = {Carbapenem resistance and biofilm formation status of Enterobacterales isolated from raw milk via molecular versus phenotypic methods.}, journal = {Antonie van Leeuwenhoek}, volume = {116}, number = {1}, pages = {67-80}, pmid = {36525156}, issn = {1572-9699}, support = {FBA-2019-2707//Çanakkale Onsekiz Mart Üniversitesi/ ; }, mesh = {Animals ; *Enterobacteriaceae/genetics ; *Milk/metabolism ; beta-Lactamases/genetics/metabolism ; Anti-Bacterial Agents/pharmacology ; Escherichia coli/metabolism ; Carbapenems/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; Bacterial Proteins/genetics ; }, abstract = {Antibiotic resistance genes can easily be transferred between bacteria in the biofilm. In the dairy industry, many bacterial species forming biofilms on the surfaces of equipment are widely reported. The experiments reported in this research paper aimed to investigate the carbapenem resistance and biofilm formation properties of Enterobacterales isolates which are spoilage microorganisms obtained from raw milk. In addition, the study determined that whether there was a relationship between the biofilm formation ability or the protein spectra of these isolates. In this study, ninety-two Enterobacterales isolates collected from 173 raw milk samples were investigated. Initially, the isolates were identified as Citrobacter braakii (n = 18), Citrobacter freundii (n = 12), Enterobacter asburiae (n = 1), Enterobacter cloacae (n = 3), Escherichia coli (n = 10), Hafnia alvei (n = 18), Klebsiella oxytoca (n = 1), Serratia fonticola (n = 24), Serratia liquefaciens (n = 4), and Serratia marcescens (n = 1) using MALDI-TOF MS. As a result, carbapenem resistance was determined in 6.5% of the isolates by CIM test, MHT, and the disk diffusion methods, but none of them had blaOXA-48, blaKPC, blaNDM-1, blaOXA23, blaOXA-58, blaOXA-51, blaVIM, and blaIMP genes. This may be due to the effect of other resistance mechanisms such as porin loss or increased flow pump activity. Furthermore, biofilm formation (weak and moderate) was detected in 97.8% of the Enterobacterales isolates. The mass spectra of the moderate biofilm producer isolate of Serratia spp. and the mass spectra of the weak biofilm producers of E.coli presented similarities.}, } @article {pmid36522527, year = {2022}, author = {Lu, Y and Natarajan, G and Nguyen, TQN and Thi, SS and Arumugam, K and Seviour, T and Williams, RBH and Wuertz, S and Law, Y}, title = {Controlling anammox speciation and biofilm attachment strategy using N-biotransformation intermediates and organic carbon levels.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {21720}, pmid = {36522527}, issn = {2045-2322}, mesh = {*Wastewater ; Carbon ; Nitrites ; Anaerobic Ammonia Oxidation ; Nitrogen Dioxide ; Oxidation-Reduction ; *Ammonium Compounds ; Nitrogen ; Bacteria ; Biotransformation ; Biofilms ; Bioreactors/microbiology ; Anaerobiosis ; }, abstract = {Conventional nitrogen removal in wastewater treatment requires a high oxygen and energy input. Anaerobic ammonium oxidation (anammox), the single-step conversion of ammonium and nitrite to nitrogen gas, is a more energy and cost effective alternative applied extensively to sidestream wastewater treatment. It would also be a mainstream treatment option if species diversity and physiology were better understood. Anammox bacteria were enriched up to 80%, 90% and 50% relative abundance, from a single inoculum, under standard enrichment conditions with either stepwise-nitrite and ammonia concentration increases (R1), nitric oxide supplementation (R2), or complex organic carbon from mainstream wastewater (R3), respectively. Candidatus Brocadia caroliniensis predominated in all reactors, but a shift towards Ca. Brocadia sinica occurred at ammonium and nitrite concentrations > 270 mg NH4-N L[-1] and 340 mg NO2-N L[-1] respectively. With NO present, heterotrophic growth was inhibited, and Ca. Jettenia coexisted with Ca. B. caroliniensis before diminishing as nitrite increased to 160 mg NO2-N L[-1]. Organic carbon supplementation led to the emergence of heterotrophic communities that coevolved with Ca. B. caroliniensis. Ca. B. caroliniensis and Ca. Jettenia preferentially formed biofilms on surfaces, whereas Ca. Brocadia sinica formed granules in suspension. Our results indicate that multiple anammox bacteria species co-exist and occupy sub-niches in anammox reactors, and that the dominant population can be reversibly shifted by, for example, changing nitrogen load (i.e. high nitrite concentration favors Ca. Brocadia caroliniensis). Speciation has implications for wastewater process design, where the optimum cell immobilization strategy (i.e. carriers vs granules) depends on which species dominates.}, } @article {pmid36522050, year = {2023}, author = {Zhang, Y and Qian, Y and Zhang, M and Qiao, W}, title = {Repairing of rutin to the toxicity of combined F-53B and chromium pollution on the biofilm formed by Pseudomonas aeruginosa.}, journal = {Journal of environmental sciences (China)}, volume = {127}, number = {}, pages = {158-168}, doi = {10.1016/j.jes.2021.12.019}, pmid = {36522050}, issn = {1001-0742}, mesh = {Animals ; *Alkanesulfonic Acids/toxicity ; *Fluorocarbons/chemistry ; Pseudomonas aeruginosa ; Zebrafish/metabolism ; Rutin/pharmacology/metabolism ; Antioxidants/metabolism ; Reactive Oxygen Species/metabolism ; *Water Pollutants, Chemical/analysis ; Chromium/toxicity/metabolism ; Superoxide Dismutase/metabolism ; Biofilms ; }, abstract = {The wastewater discharge from the process of chrome plating, which contains 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) and chromium (Cr), may be toxic to biofilm. In this study we found that the biofilm formed by Pseudomonas aeruginosa PAO1 was inhibited by exposure to a combination of F-53B and Cr(VI). The combined pollution damaged the cell membranes and the structure of the biofilm, and inhibited the production of the Pseudomonas quinolone-based signal, which affected biofilm formation. Moreover, the secretion of extracellular polymeric substances decreased as a result of this combined exposure. Exposure to F-53B and Cr(VI) individually or in combination could induce the excessive accumulation of intracellular reactive oxygen species (ROS), and the ROS positive rate of the bacteria increased under the treatment with 0.2 mmol/L of Cr(VI) and 250 nmol/L of F-53B, respectively. In addition, the activities of superoxide dismutase (SOD) and catalase (CAT) were enhanced for scavenging ROS in the bacteria that were exposed to Cr(VI) and F-53B. As an antioxidant, rutin was used to repair the toxicity of Cr(VI) and F-53B towards the biofilm formed by the bacteria. When rutin was added to the bacteria medium, with either Cr(VI) or F-53B as pollutant, or with the combined pollutants, the extracellular protein content of the bacteria recovered to 0.84, 0.94, and 0.85 times that of the control, respectively. Meanwhile, the accumulation of ROS and the activities of SOD and CAT decreased, which indicated that the addition of rutin can alleviate the oxidative stress and promote the antioxidant stress system.}, } @article {pmid36521655, year = {2023}, author = {Ji, H and Zhou, Y and Zhang, L and Wang, Y and Zhang, F and Bai, J and Li, Q and Zhang, Z}, title = {Function analysis of choline binding domains (CBDs) of LytA, LytC and CbpD in biofilm formation of Streptococcus pneumoniae.}, journal = {Microbial pathogenesis}, volume = {174}, number = {}, pages = {105939}, doi = {10.1016/j.micpath.2022.105939}, pmid = {36521655}, issn = {1096-1208}, mesh = {*Streptococcus pneumoniae/genetics/metabolism ; *Bacterial Proteins/genetics/metabolism ; Biofilms ; Choline/metabolism ; }, abstract = {Biofilm formation is an important strategy for the colonization of Streptococcus pneumoniae, which can increase the capacity to evade antibiotic and host immune stress. Extracellular choline-binding proteins (CBPs) are required for successful biofilm formation, but the function of extracellular CBPs in the process of biofilm formation is not fully understood. In this study, we tend to analyze the functions of LytA, LytC and CbpD in biofilm formation by in vitro studies with their choline-binding domains (CBDs). Biofilm formation of S. pneumoniae was enhanced when cultured in medium supplemented with CBD-C and CBD-D. Parallel assays with ChBp-Is (choline binding repeats with different C-terminal tails) and character analysis of CBDs reveal a higher isoelectric point (pI) is related to promotion of biofilm formation. Phenotype characterization of biofilms revel CBD-C and CBD-D function differently, CBD-C promoting the formation of membrane-like structures and CBD-D promoting the formation of regular reticular structures. Gene expression analysis reveals membrane transport pathways are influenced with the binding of CBDs, among which the phosphate uptake and PTS of galactose pathways are both up-regulated under conditions with CBDs. Further, extracellular substances detection revealed that extracellular proteins increased with CBD-A and CBD-D, exhibiting as increase in extracellular high molecular weight proteins. Extracellular DNA increased under CBD-A but decreased under CBD-C and CBD-D; Extracellular phosphate increased under CBD-C. These support the alterations in membrane transport pathways, and reveal diverse reactions to extracellular protein, DNA and phosphate of these three CBDs. Overall, our results indicated extracellular CBP participate in biofilm formation by affecting surface charge and membrane transport pathways of pneumococcal cells, as well as promoting reactions to extracellular substances.}, } @article {pmid36519335, year = {2022}, author = {Garg, D and Matai, I and Agrawal, S and Sachdev, A}, title = {Hybrid gum tragacanth/sodium alginate hydrogel reinforced with silver nanotriangles for bacterial biofilm inhibition.}, journal = {Biofouling}, volume = {38}, number = {10}, pages = {965-983}, doi = {10.1080/08927014.2022.2156286}, pmid = {36519335}, issn = {1029-2454}, mesh = {Humans ; Silver/pharmacology/chemistry ; Hydrogels/pharmacology/chemistry ; *Tragacanth/chemistry ; Alginates/pharmacology ; Biofilms ; Bacteria ; *Staphylococcal Infections ; Escherichia coli ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {Biomaterial associated bacterial infections are indomitable to treatment due to the rise in antibiotic resistant strains, thereby triggering the need for new antibacterial agents. Herein, composite bactericidal hydrogels were formulated by incorporating silver nanotriangles (AgNTs) inside a hybrid polymer network of Gum Tragacanth/Sodium Alginate (GT/SA) hydrogels. Physico-chemical examination revealed robust mechanical strength, appreciable porosity and desirable in vitro enzymatic biodegradation of composite hydrogels. The antibacterial activity of AgNT-hydrogel was tested against planktonic and biofilm-forming Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. For all the strains, AgNT-hydrogel showed a dose-dependent decrease in bacterial growth. The addition of AgNT-hydrogels (40-80 mg ml[-1]) caused 87% inhibition of planktonic biomass and up to 74% reduction in biofilm formation. Overall, this study proposes a promising approach for designing antibacterial composite hydrogels to mitigate various forms of bacterial infection.}, } @article {pmid36519250, year = {2022}, author = {Hassan, NH and El-Hawary, SS and Emam, M and Safwat, NA and Rabeh, MA and Abdelmohsen, UR and Selim, NM}, title = {Nephthea sp. inhibits biofilm, DNA gyrase, HSP90, and DHFR: in vitro, in silico, and pharmacokinetics studies.}, journal = {Natural product research}, volume = {}, number = {}, pages = {1-6}, doi = {10.1080/14786419.2022.2156998}, pmid = {36519250}, issn = {1478-6427}, abstract = {This study attempts to identify and assess a novel marine-derived antibiofilm agent. The antibacterial activity of n-hexane, dichloromethane, ethyl acetate, and butanol fractions from the crude extract of soft coral Nephthea sp. was evaluated against six microorganisms.Ethyl acetate fraction considered the most effective one against Bacillus subtilis, Escherichia coli, and Candida, investigated potential biofilm inhibition against the tested strains. Seventeen secondary metabolites were identified using (UPLC-Q/TOF-MS) responsible for these biological activities of the active fraction. Additionally, a molecular docking study showed free binding energy of -7.5 kcal/mol; Azamial A had the highest binding affinity for the DNA gyrase enzyme, while Sinularectin had -8.3 and -7.6 kcal/mol for the DHFR and HSP90 enzymes, respectively. Moreover, pharmacokinetics and (ADME) studies for Azamial A and Sinularectin were performed. Finally, results were confirmed by the in vitro enzymatic inhibitory effect of ethyl acetate fraction suggested in the in-silico study.}, } @article {pmid36519178, year = {2022}, author = {Afshar, M and Møllebjerg, A and Minero, GA and Hollensteiner, J and Poehlein, A and Himmelbach, A and Lange, J and Meyer, RL and Brüggemann, H}, title = {Biofilm formation and inflammatory potential of Staphylococcus saccharolyticus: A possible cause of orthopedic implant-associated infections.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1070201}, pmid = {36519178}, issn = {1664-302X}, abstract = {Staphylococcus saccharolyticus, a coagulase-negative staphylococcal species, has some unusual characteristics for human-associated staphylococci, such as slow growth and its preference for anoxic culture conditions. This species is a relatively abundant member of the human skin microbiota, but its microbiological properties, as well as the pathogenic potential, have scarcely been investigated so far, despite being occasionally isolated from different types of infections including orthopedic implant-associated infections. Here, we investigated the growth and biofilm properties of clinical isolates of S. saccharolyticus and determined host cell responses. Growth assessments in anoxic and oxic conditions revealed strain-dependent outcomes, as some strains can also grow aerobically. All tested strains of S. saccharolyticus were able to form biofilm in a microtiter plate assay. Strain-dependent differences were determined by optical coherence tomography, revealing that medium supplementation with glucose and sodium chloride enhanced biofilm formation. Visualization of the biofilm by confocal laser scanning microscopy revealed the role of extracellular DNA in the biofilm structure. In addition to attached biofilms, S. saccharolyticus also formed bacterial aggregates at an early stage of growth. Transcriptome analysis of biofilm-grown versus planktonic cells revealed a set of upregulated genes in biofilm-embedded cells, including factors involved in adhesion, colonization, and competition such as epidermin, type I toxin-antitoxin system, and phenol-soluble modulins (beta and epsilon). To investigate consequences for the host after encountering S. saccharolyticus, cytokine profiling and host cell viability were assessed by infection experiments with differentiated THP-1 cells. The microorganism strongly triggered the secretion of the tested pro-inflammatory cyto- and chemokines IL-6, IL-8, and TNF-alpha, determined at 24 h post-infection. S. saccharolyticus was less cytotoxic than Staphylococcus aureus. Taken together, the results indicate that S. saccharolyticus has substantial pathogenic potential. Thus, it can be a potential cause of orthopedic implant-associated infections and other types of deep-seated infections.}, } @article {pmid36518176, year = {2022}, author = {Cangui-Panchi, SP and Ñacato-Toapanta, AL and Enríquez-Martínez, LJ and Reyes, J and Garzon-Chavez, D and Machado, A}, title = {Biofilm-forming microorganisms causing hospital-acquired infections from intravenous catheter: A systematic review.}, journal = {Current research in microbial sciences}, volume = {3}, number = {}, pages = {100175}, pmid = {36518176}, issn = {2666-5174}, abstract = {The high prevalence of nosocomial infections is related to the use of medical insertion devices such as central venous catheters (CVCs). Most of the microorganisms causing nosocomial infections are biofilm producers, this characteristic allows them to adhere to abiotic surfaces and cause initial catheter infections that can lead to bloodstream infections. Our main goal in this systematic review was to evaluate the prevalence of biofilm among CVC-related infections, particularly among Intensive Care Unit (ICU) patients, in the studies applying different in vitro and in vivo methodologies. All studies reporting clinical isolates from patients with catheter-related nosocomial infections and biofilm evaluation published up to 24 June 2022 in the PubMed and Scopus databases were included. Twenty-five studies met the eligibility criteria and were included in this systematic review for analysis. Different methodologies were applied in the assessment of biofilm-forming microorganisms including in vitro assays, catheter-infected in vitro, and in vivo mouse models. The present study showed that between 59 and 100% of clinical isolates were able to form biofilms, and the prevalence rate of biofilm formation varied significantly between studies from different countries and regions. Among the clinical isolates collected in our study set, a wide variety of microorganisms including Gram-positive strains, Gram-negative strains, and Candida albicans were found. Many authors studied resistance mechanisms and genes related to biofilm development and surface adherence properties. In some cases, the studies also evaluated biofilm inhibition assays using various kinds of catheter coatings.}, } @article {pmid36518174, year = {2022}, author = {Woitschach, F and Kloss, M and Grabow, N and Reisinger, EC and Sombetzki, M}, title = {Mimicking critical environment factors for a static in vitro biofilm formation model on blood-contact implant materials.}, journal = {Current research in microbial sciences}, volume = {3}, number = {}, pages = {100156}, pmid = {36518174}, issn = {2666-5174}, abstract = {The prevention of implant infections is a major challenge for implant developers and clinicians. Understanding biofilm dynamics and favorable implant or environmental characteristics will help to prevent biofilm formation. Blood-contact implants, such as cardiovascular implants, are particularly susceptible to infections as the blood provides a favorable growth environment for bacteria due to its rich supply of micro- and macro substances, such as glucose and plasma proteins. In this context, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis are the most reported causes accompanying foreign body-associated infections, mainly due to their ability to form an adherent, multilayered bacterial biofilm on a wide variety of surfaces. The present study demonstrates that the provision of glucose and human plasma to the growth medium or coating of the flask with human plasma differentially affects the biofilm formation of these three bacterial species, with human plasma being the most effective regulator. However, glucose supplementation promoted and stabilized biofilm formation of S. aureus and E. faecalis, while an opposite effect was observed for additional plasma. These findings highlight the urgent need to intensify studies on the impact of host soluble factors as risk factors promoting fitness and persistence of bacterial biofilms.}, } @article {pmid36515766, year = {2023}, author = {Rayón-López, G and Carapia-Minero, N and Medina-Canales, MG and García-Pérez, BE and Reséndiz-Sánchez, J and Pérez, NO and Rodríguez-Tovar, AV and Ramírez-Granillo, A}, title = {Lipid-Like Biofilm from a Clinical Brain Isolate of Aspergillus terreus: Quantification, Structural Characterization and Stages of the Formation Cycle.}, journal = {Mycopathologia}, volume = {188}, number = {1-2}, pages = {35-49}, pmid = {36515766}, issn = {1573-0832}, support = {SIP20221965//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; SIP20210778//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; SIP20210200//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; SIP20220564//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; }, mesh = {*Aspergillus ; *Biofilms ; Fungi ; Brain ; Lipids ; }, abstract = {Invasive infections caused by filamentous fungi have increased considerably due to the alteration of the host's immune response. Aspergillus terreus is considered an emerging pathogen and has shown resistance to amphotericin B treatment, resulting in high mortality. The development of fungal biofilm is a virulence factor, and it has been described in some cases of invasive aspergillosis. In addition, although the general composition of fungal biofilms is known, findings related to biofilms of a lipid nature are rarely reported. In this study, we present the identification of a clinical strain of A. terreus by microbiological and molecular tools, also its in vitro biofilm development capacity: (i) Biofilm formation was quantified by Crystal Violet and reduction of tetrazolium salts assays, and simultaneously the stages of biofilm development were described by Scanning Electron Microscopy in High Resolution (SEM-HR). (ii) Characterization of the organizational structure of the biofilm was performed by SEM-HR. The hyphal networks developed on the surface, the abundant air channels created between the ECM (extracellular matrix) and the hyphae fused in anastomosis were described. Also, the presence of microhyphae is reported. (iii) The chemical composition of the ECM was analyzed by SEM-HR and CLSM (Confocal Laser Scanning Microscopy). Proteins, carbohydrates, nucleic acids and a relevant presence of lipid components were identified. Some structures of apparent waxy appearance were highlighted by SEM-HR and backscatter-electron diffraction, for which CLSM was previously performed. To our knowledge, this work is the first description of a lipid-type biofilm in filamentous fungi, specifically of the species A. terreus from a clinical isolate.}, } @article {pmid36515548, year = {2023}, author = {Ruiz-Sorribas, A and Poilvache, H and Kamarudin, NHN and Braem, A and Van Bambeke, F}, title = {Correction for Ruiz-Sorribas et al., "Hydrolytic Enzymes as Potentiators of Antimicrobials against an Inter-Kingdom Biofilm Model".}, journal = {Microbiology spectrum}, volume = {11}, number = {1}, pages = {e0467122}, doi = {10.1128/spectrum.04671-22}, pmid = {36515548}, issn = {2165-0497}, } @article {pmid36515197, year = {2022}, author = {Mokgope, H and Leudjo Taka, A and Klink, MJ and Pakade, VE and Walmsley, T}, title = {Quantification of some ARVs' removal efficiency from wastewater using a moving bed biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {11}, pages = {2928-2942}, doi = {10.2166/wst.2022.353}, pmid = {36515197}, issn = {0273-1223}, mesh = {Humans ; *Wastewater ; *Biofilms ; Waste Disposal, Fluid/methods ; Bioreactors ; Biological Oxygen Demand Analysis ; }, abstract = {To date, in South Africa alone, there are an estimated 4.5 million people receiving antiretroviral (ARV) therapy. This places South Africa as the country with the largest ARV therapy programme in the world. As a result, there are an increasing number of reports on the occurrence of ARVs in South African waters. Achieving efficient and bio-friendly methods for the removal of these pollutants is considered as a concern for environmental researchers. This study aims at studying the efficiency of a moving bed biofilm reactor (MBBR) system for removing ARVs from wastewater. A continuous-flow laboratory scale system was designed, built, installed, and operated at a carrier filling rate of 30%, an organic loading rate of 0.6 kg COD/m3.d-1 OLR, a hydraulic retention time of 18h, and a 27.8 mL/min flow rate. The systems were monitored over time for the elimination of conventional wastewater parameters i.e., Biological Oxygen Demand, Chemical Oxygen Demand, and nutrients. The results showed that the MBBR system as a bio-friendly method has high efficiency in removing Nevirapine, Tenofovir, Efavirenz, Ritonavir and Emtricitabine from the synthetic influent sample with an average removal of 62%, 74%, 94%, 94% and 95%, respectively, after 10 days of operation.}, } @article {pmid36514529, year = {2022}, author = {Reiferth, VM and Holtmann, D and Müller, D}, title = {Flexible biofilm monitoring device.}, journal = {Engineering in life sciences}, volume = {22}, number = {12}, pages = {796-802}, pmid = {36514529}, issn = {1618-0240}, abstract = {Biofilms and their analysis are increasingly attracting the attention of the scientific community due to the immense importance and impact of biofilms in various natural, technical and medical fields. For these purposes, an optimized and extended antibiofilm assay system based on the Calgary Biofilm Device (MBEC Assay® system) consisting of microtiter plate and PCR tubes was established. Its implementation was used to study the growth characteristics of the sessile phenotype of Pseudomonas fluorescens exposed to antimicrobial peptides. Inhibitory effects of an antimicrobial peptide on P. fluorescens biofilm formation could be determined at a concentration of 250 μg/ml (biofilm prevention concentration (BPC)) using the modified biofilm assay. Similarly, the biofilm bactericidal concentration (BBC) at 125 μg/ml and the minimum biofilm elimination concentration to remove 90% of the total biofilm mass (MBEC90) were measured at a concentration range of 15.625-1.95 μg/ml. In conclusion, this optimized system provides a highly variable, simple, and cost-effective alternative to high-throughput screening based on the Calgary Biofilm Device (CBD).}, } @article {pmid36513294, year = {2023}, author = {Sankar, S and Ganesh, PS and Subramaniam, S and Shankar, EM and Yuwanati, M and Govindasamy, R and Thiruvengadam, M}, title = {Host cell responses against the pseudomonal biofilm: A continued tale of host-pathogen interactions.}, journal = {Microbial pathogenesis}, volume = {174}, number = {}, pages = {105940}, doi = {10.1016/j.micpath.2022.105940}, pmid = {36513294}, issn = {1096-1208}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Quorum Sensing ; Virulence Factors/metabolism ; Pseudomonas aeruginosa ; Host-Pathogen Interactions ; Bacterial Proteins/metabolism ; }, abstract = {In biofilm formation, pathogens within the bacterial community coordinate a cell-cell communication system called quorum sensing (QS). This is achieved through various signalling pathways that regulate bacterial virulence and host immune response. Here, we reviewed the host responses, key clinical implications, and novel therapeutic approaches against the biofilms of P. aeruginosa. Given the high degree of intrinsic antibiotic resistance and biofilm formation by the pathogen, the ensuing treatment complications could result in high morbidity and mortality rates worldwide. Notwithstanding the availability of intervention strategies, there remains a paucity of effective therapeutic options to control biofilmogenesis. This review discusses the basic understanding of QS-associated virulence factors and several key therapeutic interventions to foil the biofilm menace of P. aeruginosa.}, } @article {pmid36512969, year = {2023}, author = {Gungor, C and Hizlisoy, H and Ertas Onmaz, N and Gundog, DA and Barel, M and Disli, HB and Dishan, A and Al, S and Yildirim, Y and Gonulalan, Z}, title = {Profile of Aliarcobacter spp. from edible giblets: Genetic diversity, antibiotic resistance, biofilm formation.}, journal = {International journal of food microbiology}, volume = {386}, number = {}, pages = {110047}, doi = {10.1016/j.ijfoodmicro.2022.110047}, pmid = {36512969}, issn = {1879-3460}, mesh = {Animals ; Humans ; *Virulence Factors/genetics ; Phylogeny ; *Arcobacter ; Meat ; Drug Resistance, Microbial ; Genetic Variation ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Aliarcobacter spp. are recognized as emerging foodborne pathogens and consumption of foods contaminated with them can be a hazard to human and animal health. This study was conducted to investigate the prevalence of Aliarcobacter spp. in edible internal organs of different animal species from retail markets and giblet sellers. Additionally, this study was focused on the antimicrobial resistance, virulence profiles, biofilm-forming capabilities, and phylogenetic relationships of obtained isolates. A total of 270 samples were analyzed from which, 28 (10.4 %) were isolated as Aliarcobacter spp. by conventional methods. Within the 28 Aliarcobacter spp. isolates, 17 (60.7 %) were identified as A. butzleri, 10 (35.7 %) were A. cryaerophilus and one (3.5 %) was A. skirrowii by PCR method. The disc diffusion method showed that the highest resistance rate of Aliarcobacter spp. was seen against oxacillin (78.5 %), and 20 (71.4 %) out of the 28 isolates exhibited multidrug resistance (MDR). Out of the 28 isolates, mviN, pldA, tlyA, and hecB virulence genes were detected in 85.7 %, 46.4 %, 46.4 %, and 3.5 %, respectively, but irgA, Cj1349, ciaB, cadF, and hecA genes were not detected. According to the microplate test, 27 (96.4 %) isolates had weak biofilm ability while one A. cryaerophilus isolate (3.6 %) exhibited strong biofilm formation. ERIC-PCR band patterns suggested that isolated Aliarcobacter spp. from giblets, have different contamination sources. The presence of pathogenic and multidrug-resistant Aliarcobacter spp. in food poses a potential risk to public health and control measures throughout the food chain are necessary to prevent the spread of these strains.}, } @article {pmid36512427, year = {2023}, author = {Zou, Z and Potter, RF and McCoy, WH and Wildenthal, JA and Katumba, GL and Mucha, PJ and Dantas, G and Henderson, JP}, title = {E. coli catheter-associated urinary tract infections are associated with distinctive virulence and biofilm gene determinants.}, journal = {JCI insight}, volume = {8}, number = {2}, pages = {}, pmid = {36512427}, issn = {2379-3708}, support = {K08 AR076464/AR/NIAMS NIH HHS/United States ; KL2 TR002346/TR/NCATS NIH HHS/United States ; R01 DK111930/DK/NIDDK NIH HHS/United States ; R01 DK125860/DK/NIDDK NIH HHS/United States ; }, mesh = {Humans ; *Bacteriuria/microbiology ; Biofilms ; *Catheters/adverse effects ; *Escherichia coli/genetics ; Escherichia coli Proteins ; Receptors, Cell Surface ; *Urinary Tract Infections/microbiology ; Virulence ; }, abstract = {Urinary catheterization facilitates urinary tract colonization by E. coli and increases infection risk. Here, we aimed to identify strain-specific characteristics associated with the transition from colonization to infection in catheterized patients. In a single-site study population, we compared E. coli isolates from patients with catheter-associated asymptomatic bacteriuria (CAASB) to those with catheter-associated urinary tract infection (CAUTI). CAUTI isolates were dominated by a phylotype B2 subclade containing the multidrug-resistant ST131 lineage relative to CAASB isolates, which were phylogenetically more diverse. A distinctive combination of virulence-associated genes was present in the CAUTI-associated B2 subclade. Catheter-associated biofilm formation was widespread among isolates and did not distinguish CAUTI from CAASB strains. Preincubation with CAASB strains could inhibit catheter colonization by multiple ST131 CAUTI isolates. Comparative genomic analysis identified a group of variable genes associated with high catheter biofilm formation present in both CAUTI and CAASB strains. Among these, ferric citrate transport (Fec) system genes were experimentally associated with enhanced catheter biofilm formation using reporter and fecA deletion strains. These results are consistent with a variable role for catheter biofilm formation in promoting CAUTI by ST131-like strains or resisting CAUTI by lower-risk strains that engage in niche exclusion.}, } @article {pmid36510276, year = {2022}, author = {Choi, E and Wells, B and Mirabella, G and Atkins, E and Choi, S}, title = {Anti-biofilm activity of Pseudomonas fluorescens culture supernatants on biofilm formation of Staphylococcus epidermidis 1457.}, journal = {BMC research notes}, volume = {15}, number = {1}, pages = {370}, pmid = {36510276}, issn = {1756-0500}, support = {2016R1D1A1B01009752//Basic Science Research Program through the National Research Foundation of Korea (NRF)/ ; }, mesh = {Humans ; Staphylococcus epidermidis ; *Pseudomonas fluorescens ; Biofilms ; Polysaccharides, Bacterial ; Anti-Bacterial Agents/pharmacology ; Staphylococcus ; *Staphylococcal Infections ; }, abstract = {OBJECTIVE: Staphylococcus epidermidis is a skin colonizer and a major cause of nosocomial infections that can lead to sepsis. It causes opportunistic infections by forming biofilms on medical devices, which are hard to control with conventional antibiotics. In an attempt to develop its biofilm inhibitors, the culture supernatant (CS) of Pseudomonas fluorescens was assessed. This study examined the effect of the CS on S. epidermidis 1457 biofilm formation, the characteristics of inhibitors in the CS, and the differential gene expression of S. epidermidis when treated with the CS.

RESULTS: P. fluorescens CS specifically targeted the maturation stage of S. epidermidis biofilm formation while not affecting planktonic growth. RT-qPCR analysis revealed that P. fluorescens CS significantly downregulated S. epidermidis ica genes and upregulated an ica repressor, tcaR. This indicates that the CS reduced polysaccharide intercellular adhesin synthesis, a major component of the S. epidermidis 1457 biofilm matrix. Further studies are required to elucidate the specific inhibitory components in the CS and their mechanism of action. Our results indicate that inhibitors in the P. fluorescens CS may have a significant value for inhibiting S. epidermidis biofilm. Combinations of specific inhibitors from the CS and antibiotics against staphylococci may provide an effective measure to control S. epidermidis biofilm formation while avoiding antibiotic resistance and compensating the attenuated effectiveness of antibiotics on biofilms.}, } @article {pmid36509018, year = {2023}, author = {Pellé, J and Longo, M and Le Poul, N and Hellio, C and Rioual, S and Lescop, B}, title = {Electrochemical monitoring of the Pseudomonas aeruginosa growth and the formation of a biofilm in TSB media.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {150}, number = {}, pages = {108344}, doi = {10.1016/j.bioelechem.2022.108344}, pmid = {36509018}, issn = {1878-562X}, mesh = {*Bacterial Adhesion ; Pseudomonas aeruginosa ; Biofilms ; *Biofouling/prevention & control ; Carbon ; }, abstract = {Understanding and sensing microbial biofilm formation onto surfaces remains highly challenging for preventing corrosion and biofouling processes. For that purpose, we have thoroughly investigated biofilm formation onto glassy carbon electrode surfaces by using electrochemical technics. Pseudomonas aeruginosa was studied because of its remarkable ability to form biofilms in many environments. The modification of the electrode-solution interface during biofilm growth was monitored by in-situ measurement of the open-circuit potential and correlated with results obtained by electrochemical impedance spectroscopy, cyclic voltammetry, scanning electron microscopy and bioassays. The sensing of the biofilm formation hence suggests a multi-steps mechanism, which may include pre-formation of an insulating layer onto the surface prior to the bacteria adhesion and biofilm formation.}, } @article {pmid36508189, year = {2022}, author = {Tanaka, T and Horie, T}, title = {Development of an in vitro biofilm formation model for screening anti-periodontal disease agents.}, journal = {American journal of dentistry}, volume = {35}, number = {6}, pages = {323-328}, pmid = {36508189}, issn = {0894-8275}, mesh = {Humans ; *Treponema denticola ; Porphyromonas gingivalis ; *Periodontal Diseases ; Biofilms ; }, abstract = {PURPOSE: To devise a method for artificial biofilm formation using Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Streptococcus gordonii, as well as a method for evaluating the effects of various ingredients on the artificial biofilm.

METHODS: An artificial biofilm was developed using P. gingivalis, T. forsythia, T. denticola, and S. gordonii, which was then observed using scanning electron microscopy and evaluated by microflora analysis. The artificial biofilm was exposed to chlorhexidine gluconate and stained with a fluorescent dye. Then, the fluorescent-stained biofilm was observed using a confocal laser microscope and measured using a fluorescent microplate reader.

RESULTS: The microflora analysis confirmed that the culture medium developed was capable of culturing four different bacterial species at the same time. The distribution of dead bacteria differed according to the difference in the concentration of exposed chlorhexidine gluconate. Moreover, the rate of attachment of viable cells decreased in a concentration-dependent manner. Many bacteria were detached from the biofilm in the group exposed to 0.09% chlorhexidine gluconate. Exposure to chlorhexidine gluconate induced a concentration-dependent decrease in living microorganisms and an increase in dead microorganisms in the biofilm.

CLINICAL SIGNIFICANCE: The results of this study revealed that S. gordonii, P. gingivalis, T. forsythia, and T. denticola could be used to develop artificial biofilms. The effects of chlorhexidine gluconate on the biofilm showed that evaluating the change in the artificial biofilm caused by the component effect in the experiments was possible via exposure to chlorhexidine gluconate. This method can efficiently evaluate the component effect and has a high potential for use as an indicator. This study demonstrated that this simulation could help develop preventive measures.}, } @article {pmid36508003, year = {2022}, author = {Cui, G and Li, P and Wu, R and Lin, H}, title = {Streptococcus mutans membrane vesicles inhibit the biofilm formation of Streptococcus gordonii and Streptococcus sanguinis.}, journal = {AMB Express}, volume = {12}, number = {1}, pages = {154}, pmid = {36508003}, issn = {2191-0855}, support = {No. 81970928//National Natural Science Foundation of China/ ; }, abstract = {Streptococcus mutans, whose main virulence factor is glucosyltransferase (Gtf), has a substantial impact on the development of dental caries. S. mutans membrane vesicles (MVs), which are rich in Gtfs, have been shown to affect biofilm formation of other microorganisms. Streptococcus gordonii and Streptococcus sanguinis are initial colonizers of tooth surfaces, which provide attachment sites for subsequent microorganisms and are crucial in the development of oral biofilms. S. mutans and S. gordonii, as well as S. mutans and S. sanguinis, have a complex competitive and cooperative relationship, but it is unclear whether S. mutans MVs play a role in these interspecific interactions. Therefore, we co-cultured S. mutans MVs, having or lacking Gtfs, with S. gordonii and S. sanguinis. Our results showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis but did not affect their planktonic growth; contrastingly, S. mutans ΔgtfBC mutant MVs had little effect on both their growth and biofilm formation. Additionally, there were fewer and more dispersed bacteria in the biofilms of the S. mutans MV-treated group than that in the control group. Furthermore, the expression levels of the biofilm-related virulence factors GtfG, GtfP, and SpxB in S. gordonii and S. sanguinis were significantly downregulated in response to S. mutans MVs. In conclusion, the results of our study showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis, revealing an important role for MVs in interspecific interactions.}, } @article {pmid36507979, year = {2022}, author = {Shaikh, SA and Patel, B and Priyadarsini, IK and Vavilala, SL}, title = {Combating planktonic and biofilm growth of Serratia marcescens by repurposing ebselen.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {}, number = {}, pages = {}, pmid = {36507979}, issn = {1618-1905}, abstract = {AIM OF THE STUDY: The rising instances of multidrug-resistant pathogens are rapidly evolving into a global healthcare crisis. Identifying new ways of synthesis of antibiotics is both time-consuming and expensive. Repurposing existing drugs for the treatment of such antimicrobial-resistant pathogens has also been explored.

METHODS AND RESULTS: In the current study, ebselen was screened for antibacterial and antibiofilm activity against Serratia marcescens. Various antibacterial studies such as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curves, intracellular reactive oxygen species (ROS) quantification, and colony-forming unit assays were performed. The antibiofilm potential was assayed by biofilm inhibition, cell surface hydrophobicity assay, eradication, quantification of extracellular DNA (eDNA), and extracellular polymeric substance (EPS) layer and scanning electron microscopy (SEM) analysis were performed. Anti-quorum sensing assay was validated by quantifying the virulence factors production. Further molecular docking of ebselen with two quorum sensing (QS) specific proteins was also carried out. Antibacterial susceptibility tests showed potent antimicrobial activity of ebselen against S. marcescens with MIC50 of 14 μg/mL. Ebselen's ability to disturb the redox environment by inducing significant ROS generation led to bacterial death. It also showed concentration-dependent bactericidal activity as indicated by reduced bacterial growth and colony-forming unit propagation. Ebselen was also found to prevent biofilm attachment by altering the cell surface hydrophobicity while also being effective against preformed biofilms as validated by scanning electron microscopy (SEM) analysis. Additionally, ebselen showed reduced virulence factors like urease enzyme activity and prodigiosin pigment production indicating its promising anti-quorum sensing potential. Molecular docking analysis validated the strong binding of ebselen with QS-specific proteins (1Joe and PigG) with binding energies of - 6.6 and - 8.1kj/mol through hydrogen bonds and aromatic interactions. These results show that ebselen has potent antibiofilm potential that can be explored to identify treatment against bacterial infections.}, } @article {pmid36507687, year = {2023}, author = {Yi, L and Fan, Q and Wang, H and Fan, H and Zuo, J and Wang, Y and Wang, Y}, title = {Establishment of Streptococcus suis Biofilm Infection Model In Vivo and Comparative Analysis of Gene Expression Profiles between In Vivo and In Vitro Biofilms.}, journal = {Microbiology spectrum}, volume = {11}, number = {1}, pages = {e0268622}, pmid = {36507687}, issn = {2165-0497}, mesh = {Animals ; Swine ; *Transcriptome ; *Streptococcus suis/genetics/metabolism ; Persistent Infection ; Biofilms ; Lung ; }, abstract = {Streptococcus suis is a zoonotic pathogen that continuously threatens animal husbandry and public health worldwide. Studies have shown that S. suis can cause persistent infection by forming biofilms. In this study, a model of S. suis biofilm-related infection was successfully constructed for the first time by simulating the natural infection of S. suis, and biofilm of S. suis in vivo was successfully observed in the lung tissue of infected pigs by a variety of detection methods. Subsequently, selective capture of transcribed sequences (SCOTS) was used to identify genes expressed by S. suis in vivo biofilms. Sixty-nine genes were captured in in vivo biofilms formed by S. suis for the first time by SCOTS; they were mainly involved in metabolism, cell replication, and division, transport, signal transduction, cell wall, etc. Genes related to S. suis in vitro biofilm formation were also identified by SCOTS and RNA sequencing. Approximately half of the genes captured by SCOTS in the in vivo and in vitro biofilms were found to be different. In summary, our study provides powerful clues for future exploration of the mechanisms of S. suis biofilm formation. IMPORTANCE Streptococcus suis is considered an important zoonotic pathogen, and persistent infection caused by biofilm is currently considered to be the reason why S. suis is difficult to control in swine. However, to date, a model of the biofilm of S. suis in vivo has not been successfully constructed. Here, we successfully detected biofilms of S. suis in vivo in lung tissues of piglets infected with S. suis. Selective capture of transcribed sequences and the transcriptome were used to obtain gene profiles of S. suis in vivo and in vitro biofilms, and the results showed large differences between them. Such data are of importance for future experimental studies exploring the mechanism of biofilm formation by S. suis in vivo.}, } @article {pmid36506630, year = {2022}, author = {Khan, A and Nikhil, V and Pandey, A and Chaturvedi, P}, title = {Effectiveness of polyhexamethylene biguanide, chlorhexidine, and calcium hydroxide intracanal medicament against intraradicular mature polymicrobial biofilm: A microbiological study.}, journal = {Journal of conservative dentistry : JCD}, volume = {25}, number = {5}, pages = {536-540}, pmid = {36506630}, issn = {0972-0707}, abstract = {AIM: To compare the effectiveness of different intracanal medicaments against polymicrobial biofilm formed by Enterococcus faecalis, Staphylococcus aureus, and Candida albicans.

MATERIALS AND METHODS: Eighty mature human roots with intraradicular polymicrobial biofilm were randomly assigned into four groups (n = 20). Intracanal medicaments 0.2% polyhexamethylene biguanide (PHMB), 2% chlorhexidine (CHX), and calcium hydroxide (CH) were applied into the root canals. Collected dentine samples were tested at 7[th], 15[th], and 30[th] day for microbial growth, and the colony-forming units per ml (CFU/ml) were determined.

RESULTS: The CFU/ml data were analyzed using unpaired t-test and one-way ANOVA-F comparison test. All medicaments resulted in a significant reduction (P < 0.05) in microbial growth at all time intervals compared to the control group. CHX and PHMB showed a similar reduction in CFU/ml at 7[th] and 15[th] day but significantly more than CH at all time intervals. At 30[th] day, PHMB caused a significantly more reduction in CFU/ml than CHX.

CONCLUSIONS: All the three tested intracanal medicaments such as CH, CHX, and PHMB Gel were effective in reducing the microbial count. CH has a limited antimicrobial effect against the polymicrobial biofilm found inside the root canal. 2% CHX gel has a time-dependent antimicrobial effect. PHMB has a superior antimicrobial effect in comparison with CHX and CH.}, } @article {pmid36506481, year = {2022}, author = {Li, L and Lin, Z and Lu, X and Chen, C and Xie, A and Tang, Y and Zhang, Z}, title = {Photo-controlled and photo-calibrated nanoparticle enabled nitric oxide release for anti-bacterial and anti-biofilm applications.}, journal = {RSC advances}, volume = {12}, number = {51}, pages = {33358-33364}, pmid = {36506481}, issn = {2046-2069}, abstract = {After numerous efforts to elucidate the biological role of nitric oxide (NO), NO treatments have become a hotspot at the forefront of medicine. NO-releasing substances are constantly needed, while the direct use of NO gas is unattainable in bio-systems. An ideal NO donor should possess controllable and visible NO-release capability. The reported NO donating nanoparticles, prepared via encapsulating a hydrophobic NO-releasing compound into DSPE-PEG2000, meet the criteria mentioned previously. The localization and flux of NO released from these nanoparticles could be manipulated by UV or blue light. Meanwhile, NOD-NPs emit a dose-dependent fluorescence intensity to calibrate the generation of NO. While the good biocompatibility of NOD-NPs has been validated, the NO from our nanoparticles demonstrates efficient anti-bacterial and anti-biofilm effects toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Therefore, the NOD-NPs developed in this work have potential application in evaluating the regulation of microbes by NO.}, } @article {pmid36504793, year = {2022}, author = {Bian, Z and Liu, W and Jin, J and Hao, Y and Jiang, L and Xie, Y and Zhang, H}, title = {Rcs phosphorelay affects the sensitivity of Escherichia coli to plantaricin BM-1 by regulating biofilm formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1071351}, pmid = {36504793}, issn = {1664-302X}, abstract = {Introduction: Plantaricin BM-1 is a class IIa bacteriocin produced by Lactobacillus plantarum BM-1 that exerts significant antibacterial activity against many foodborne bacteria. Studies have shown that class IIa bacteriocins inhibit Gram-positive bacteria via the mannose phosphotransferase system; however, their mechanism of action against Gram-negative bacteria remains unknown. In this study, we explored the mechanism through which the Rcs phosphorelay affects the sensitivity of Escherichia coli K12 cells to plantaricin BM-1. Methods and Results: The minimum inhibitory concentrations of plantaricin BM-1 against E. coli K12, E. coli JW5917 (rcsC mutant), E. coli JW2204 (rcsD mutant), and E. coli JW2205 (rcsB mutant) were 1.25, 0.59, 1.31, and 1.22 mg/ml, respectively. Growth curves showed that E. coli JW5917 sensitivity to plantaricin BM-1 increased to the same level as that of E. coli K12 after complementation. Meanwhile, scanning electron microscopy and transmission electron microscopy revealed that, under the action of plantaricin BM-1, the appearance of E. coli JW5917 cells did not significantly differ from that of E. coli K12 cells; however, cell contents were significantly reduced and plasmolysis and shrinkage were observed at both ends. Crystal violet staining and laser scanning confocal microscopy showed that biofilm formation was significantly reduced after rcsC mutation, while proteomic analysis identified 382 upregulated and 260 downregulated proteins in E. coli JW5917. In particular, rcsC mutation was found to affect the expression of proteins related to biofilm formation, with growth curve assays showing that the deletion of these proteins increased E. coli sensitivity to plantaricin BM-1. Discussion: Consequently, we speculated that the Rcs phosphorelay may regulate the sensitivity of E. coli to plantaricin BM-1 by affecting biofilm formation. This finding of class IIa bacteriocin against Gram-negative bacteria mechanism provides new insights.}, } @article {pmid36504526, year = {2022}, author = {Fessia, A and Sartori, M and García, D and Fernández, L and Ponzio, R and Barros, G and Nesci, A}, title = {In vitro studies of biofilm-forming Bacillus strains, biocontrol agents isolated from the maize phyllosphere.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100097}, pmid = {36504526}, issn = {2590-2075}, abstract = {We aimed to assess how biofilm formation by three Bacillus isolates was affected by changes in temperature, water potential, growth media, time, and the combinations between these factors. The strains had been selected as potential biological control agents (BCAs) in earlier studies, and they were identified as B. subtilis and B. velezensis spp. through 16 rRNA sequencing and MALDI-TOF MS. Maize leaves (ML) were used as one of the growth media, since they made it possible to simulate the nutrient content in the maize phyllosphere, from which the bacteria were originally isolated. The strains were able to form biofilm both in ML and biofilm-inducing MSgg after 24, 48, and 72 h. Biofilm development in the form of pellicles and architecturally complex colonies varied morphologically from one strain to another and depended on the conditions mentioned above. In all cases, colonies and pellicles were less complex when both temperature and water potential were lower. Scanning electron microscopy (SEM) revealed that changing levels of complexity in pellicles were correlated with those in colonies. Statistical analyses found that the quantification of biofilm produced by the isolates was influenced by all the conditions tested. In terms of motility (which may contribute to biofilm formation), swimming and swarming were possible for all strains in 0.3 and 0.7% agar, respectively. A more in-depth understanding of how abiotic factors influence biofilm formation can contribute to a more effective use of these biocontrol strains against pathogens in the maize phyllosphere.}, } @article {pmid36504269, year = {2023}, author = {Kugler, A and Trivelpiece, C and Brigmon, RL}, title = {Foamed glass ceramics-an upcycled scaffold for microbial biofilm development.}, journal = {Biotechnology letters}, volume = {45}, number = {2}, pages = {225-233}, pmid = {36504269}, issn = {1573-6776}, mesh = {*Escherichia coli K12 ; Biofilms ; Glass ; Ceramics ; Escherichia coli ; }, abstract = {Glass, a near infinitely recyclable material, can be upcycled to create new products such as foamed glass ceramics, which are essentially a synthetic pumice-like material. This material has been demonstrated to sustain preserved biofilms which have application in various fields based on the deployability of the product and the preserved microbes. Foamed glass ceramics have increased surface area compared to typical soda-lime glass cullet. This material has been explored for variety of applications including the growth, storage and transport of biofilms and microbial colonies which can be preserved and deployed later. Here, we demonstrate the ability for microbial cultures including BioTiger™, Escherichia coli K-12, Bacillus thuringiensis, and two environmental eukaryotic cells to colonize the upcycled glass products, undergo preservation, and regrow after 84 days of storage. The growth of preserved samples is correlated to the time spent incubating prior to preservation. These results demonstrate the applicability of this novel glass-biofilm combination in which various preserved microorganisms are able to be rapidly grown after storage on an upcycled glass product.}, } @article {pmid36503795, year = {2023}, author = {Zhao, Y and Gao, J and Zhou, X and Li, Z and Zhao, C and Jia, X and Ji, M}, title = {Bio-immobilization and recovery of chromium using a denitrifying biofilm system: Identification of reaction zone, binding forms and end products.}, journal = {Journal of environmental sciences (China)}, volume = {126}, number = {}, pages = {70-80}, doi = {10.1016/j.jes.2022.03.050}, pmid = {36503795}, issn = {1001-0742}, mesh = {*Chromium ; *Biofilms ; Extracellular Polymeric Substance Matrix ; Wastewater ; }, abstract = {Chromium is an important resource in strategic metals. Different from most studies focusing on the bio-reduction of hexavalent chromium [Cr(VI)], this study aims to achieve the immobilization and recovery of chromium using a sequencing batch biofilm reactor. Results showed that Cr(VI) removal efficiency remained more than 99%, and 97% of reduced Cr(III) was immobilized in the biofilm. Immobilization zone, chromium forms and extracellular polymeric substances composition changes were combined to reveal the mechanism of Cr(VI) reduction and immobilization. The chromium distribution in biofilm demonstrated that intercellular layer was the main active zone with an immobilization amount of 891.70±126.32 mg/g-VSS. The reduced products analysis confirmed that trivalent chromium [Cr(III)] chelated with carboxyl, amino and other functional groups and immobilized in the form of organic Cr(III). The digestion method realized a chromium recovery efficiency of 74.59%. This study provides an alternative method for the bioremediation and resources recovery in chromium polluted wastewater.}, } @article {pmid36503089, year = {2023}, author = {Zhu, Z and Zhang, L and Li, X and Zhang, Q and Wang, S and Peng, Y}, title = {Robust nitrogen removal from municipal wastewater by partial nitrification anammox at ultra-low dissolved oxygen in a pure biofilm system.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128453}, doi = {10.1016/j.biortech.2022.128453}, pmid = {36503089}, issn = {1873-2976}, mesh = {*Wastewater ; *Nitrification ; Denitrification ; Anaerobic Ammonia Oxidation ; Nitrogen ; Oxygen ; Oxidation-Reduction ; Bioreactors/microbiology ; Biofilms ; Nitrites ; Bacteria ; Sewage ; }, abstract = {Efficient nitrogen removal from municipal wastewater applying a pure biofilm system has promise. In this study, a partial nitrification anammox (PNA) pure biofilm system was established in a sequencing batch reactor with anaerobic/oxic/anoxic operation; using this reactor, robust nitrogen removal from municipal wastewater at ambient temperature was achieved with a nitrogen removal efficiency (NRE) of 93.3 %. Partial nitrification with anammox could be coupled at dominant nitrite-oxidizing bacteria (NOB) abundance by controlling ultra-low dissolved oxygen (<0.1 mg/L) in the aerobic section where the contribution to nitrogen removal was 79.4 %. Microorganisms with different oxygen affinity spatially distributed on the carrier. Ammonia-oxidizing bacteria (AOB) dominated on the surface of the carrier, while anammox bacteria dominated on the interior of the carrier, with their relative abundance increasing from 0.26 % to 1.78 %. The intercalary NOB were inhibited by the restricted oxygen transfer. Overall, this study provides a new approach to realize PNA in biofilm system.}, } @article {pmid36500844, year = {2022}, author = {Tang, M and Ding, G and Lu, X and Huang, Q and Du, H and Xiao, G and Wang, D}, title = {Exposure to Nanoplastic Particles Enhances Acinetobacter Survival, Biofilm Formation, and Serum Resistance.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {23}, pages = {}, pmid = {36500844}, issn = {2079-4991}, abstract = {The interaction between nanoplastics and bacteria remains still largely unclear. In this study, we determined the effect of nanopolystyrene particle (NP) on a bacterial pathogen of Acinetobacter johnsonii AC15. Scanning electron microscopy (SEM) analysis indicated the aggregation of NPs from 10 μg/L to 100 μg/L on surface of A. johnsonii AC15, suggesting that A. johnsonii AC15 acted as the vector for NPs. Exposure to 100−1000 μg/L NPs increased the growth and colony-forming unit (CFU) of A. johnsonii AC15. In addition, exposure to 100−1000 μg/L NPs enhanced the amount of formed biofilm of A. johnsonii AC15. Alterations in expressions of 3 survival-related (zigA, basD, and zur), 5 biofilm formation-related (ompA, bap, adeG, csuC, and csuD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were observed after exposure to 1000 μg/L NPs. Moreover, both CFU and survival rate of A. johnsonii AC15 in normal human serum (NHS) were significantly increased by 1−1000 μg/L NPs, suggesting the enhancement in serum resistance of Acinetobacter pathogen by NPs. In the NHS, expressions of 3 survival-related (zigA, basD, and zur), 9 biofilm formation-related (ompA, bap, adeF, adeG, csuA/B, csuC, csuD, csuE, and hlyD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were affected by 1000 μg/L NPs. Expressions of 1 survival-related (zigA), 5 biofilm formation-related (bap, adeG, csuC, csuD, and csuE), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were also altered by 10 μg/L NPs after the addition of NHS. Therefore, exposure to NPs in the range of μg/L has the potential to enhance bacterial virulence by increasing their growth, biofilm formation, and serum resistance.}, } @article {pmid36498098, year = {2022}, author = {Li, J and Shen, Y and Zuo, J and Gao, S and Wang, H and Wang, Y and Yi, L and Hou, X and Wang, Y}, title = {Inhibitory Effect of Monoterpenoid Glycosides Extracts from Peony Seed Meal on Streptococcus suis LuxS/AI-2 Quorum Sensing System and Biofilm.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {23}, pages = {}, pmid = {36498098}, issn = {1660-4601}, support = {32172852//National Natural Science Foundation of China/ ; 31902309//National Natural Science Foundation of China/ ; 222300420005//Henan Provincial Science Fund for Distinguished Young Scholars/ ; 202101510003//Central Plains Scholars Fund of Henan Province/ ; 2101099A//Funded Project of Henan Province Traditional Chinese Medicine Industry Technology System and Luoyang Rural Revitalization Project/ ; }, mesh = {*Streptococcus suis/metabolism ; Homoserine/metabolism/pharmacology ; Carbon-Sulfur Lyases/metabolism/pharmacology ; *Paeonia ; Glycosides/pharmacology ; Molecular Docking Simulation ; Bacterial Proteins/metabolism ; Lactones/pharmacology ; Biofilms ; Anti-Bacterial Agents/pharmacology/metabolism ; }, abstract = {Streptococcus suis LuxS/AI-2 quorum sensing system regulates biofilm formation, resulting in increased pathogenicity and drug resistance, and diminished efficacy of antibiotic treatment. The remaining peony seed cake after oil extraction is rich in monoterpenoid glycosides, which can inhibit the formation of bacterial biofilm. In this study, we investigated the effect of seven major monocomponents (suffruticosol A, suffruticosol B, suffruticosol C, paeonifloin, albiflorin, trans-ε-viniferin, gnetin H) of peony seed meal on minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of S. suis. The results showed that the MICs of the seven single components were all greater than 200 μg/mL, with no significant bacteriostatic and bactericidal advantages. Crystal violet staining and scanning electron microscope observation showed that the seven single components had a certain inhibitory effect on the biofilm formation ability of S. suis at sub-MIC concentration. Among them, the ability of paeoniflorin to inhibit biofilm was significantly higher than that of the other six single components. AI-2 signaling molecules were detected by bioreporter strain Vibrio harvey BB170. The detection results of AI-2 signal molecules found that at 1/2 MIC concentration, paeoniflorin significantly inhibited the production of S. suis AI-2 signal, and the inhibitory effect was better than that of the other six single components. In addition, molecular docking analysis revealed that paeoniflorin had a significant binding activity with LuxS protein compared with the other six single components. The present study provides evidence that paeoniflorin plays a key role in the regulation of the inhibition of S. suis LuxS/AI-2 system and biofilm formation in peony seed meal.}, } @article {pmid36496670, year = {2022}, author = {Gemba, M and Rosiak, E and Nowak-Życzyńska, Z and Kałęcka, P and Łodykowska, E and Kołożyn-Krajewska, D}, title = {Factors Influencing Biofilm Formation by Salmonella enterica sv. Typhimurium, E. cloacae, E. hormaechei, Pantoea spp., and Bacillus spp. Isolated from Human Milk Determined by PCA Analysis.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {23}, pages = {}, pmid = {36496670}, issn = {2304-8158}, abstract = {Bacteria enter milk during poor hygiene practices and can form a biofilm on surfaces that come into contact with human milk. The presence of a biofilm increases the risk of infections among newborns as bacteria protected by biofilm are resistant to washing and disinfection processes. The formation of the biofilm depends on the microbial species, environmental conditions, and the specific materials colonized. The aim of this study is to analyze the effects of factors such as temperature, incubation time, and initial cell concentration on biofilm formation by pathogenic bacteria isolated from human milk on model hydrophobic polystyrene surfaces. Model studies confirm that pathogenic bacteria appearing in human milk as a result of cross-contamination tend to form a biofilm. The majority of isolates formed biofilm at both 25 and 37 °C after 12 h at 1 × 10[3] CFU/mL inoculum count. Multivariate principal component analysis (PCA) showed that at lower temperatures, biofilm formation by bacterial isolates was the main determinant of biofilm formation, other factors were less important; however, at 37 °C, time was a factor in biofilm formation. The model research performed underlines the importance of maintaining the proper hygiene of rooms, surfaces, and devices for expressing, storing, and preparing mothers' milk and powdered infant formula (PIF) in facilities responsible for feeding newborns and premature babies.}, } @article {pmid36495575, year = {2022}, author = {Chung, PH and Leong, JY and Wallen, JJ and Stanton, W and Diaz, N and Phillips, CD and Henry, GD}, title = {Molecular testing with next-generation sequencing appears to identify biofilm on penile prostheses better than traditional cultures: The new gold standard?.}, journal = {The Canadian journal of urology}, volume = {29}, number = {6}, pages = {11348-11354}, pmid = {36495575}, issn = {1195-9479}, mesh = {Humans ; *Penile Prosthesis ; Biofilms ; High-Throughput Nucleotide Sequencing ; Reoperation ; Molecular Diagnostic Techniques ; }, abstract = {INTRODUCTION: Traditional culture is the current standard-of-care to determine therapeutic antibiotics for patients suffering from penile prostheses (PP) infections. However, approximately 50% of PPs removed for infection are culture negative. Next-generation sequencing (NGS) compares DNA sequences to reference sequences with known microbial taxonomies to identify isolates and report relative abundances. We aim to compare the ability for standard culture and NGS techniques to identify microorganisms and biofilm composition on PPs.

MATERIALS AND METHODS: Ninety-one PPs explanted for mechanical malfunction were included in this study. Devices removed for infection or erosion were excluded. During revision surgery, two specimens were collected and sent for culture testing at institutional laboratory and for NGS testing (MicroGenDx, Lubbock, TX, USA). Species' relative abundances, sample diversity and richness, and compositional differences among samples were analyzed.

RESULTS: NGS had a higher rate of microbial detection (n = 72, 79.1%) compared to culture results (n = 3, 3.3%). Some of the bacteria identified using both methods were known prosthetic infectious pathogens, with NGS producing more isolates (mean: 11) than culture (mean: 1). Escherichia coli was the most abundant and most frequently occurring bacteria detected on NGS. Coagulase-negative Staphylococci were the most common bacteria detected on traditional culture.

CONCLUSIONS: NGS appears to be beneficial in its thorough analysis of PP biofilm composition when compared to culture methods. We hope that further research will be able to demonstrate a clinical benefit of NGS in characterizing distinct microbiomes and biofilms of infected PP, which can aid in tailoring antimicrobial therapy and improving patient outcomes.}, } @article {pmid36494632, year = {2022}, author = {Kavvalou, A and Stehling, F and Tschiedel, E and Kehrmann, J and Walkenfort, B and Hasenberg, M and Olivier, M and Steindor, M}, title = {Biofilm infection of a central venous port-catheter caused by Mycobacterium avium complex in an immunocompetent child with cystic fibrosis.}, journal = {BMC infectious diseases}, volume = {22}, number = {1}, pages = {921}, pmid = {36494632}, issn = {1471-2334}, mesh = {Humans ; Child ; Mycobacterium avium Complex/genetics ; *Cystic Fibrosis/complications/microbiology ; *Mycobacterium avium-intracellulare Infection/diagnosis/microbiology ; *Central Venous Catheters ; *Mycobacterium Infections, Nontuberculous/diagnosis/drug therapy/microbiology ; Sputum/microbiology ; *Mycobacterium ; Nontuberculous Mycobacteria ; }, abstract = {BACKGROUND: Mycobacterium (M.) chimaera is a non-tuberculous mycobacterium (NTM) that belongs to M. avium complex (MAC). In patients with cystic fibrosis (CF), MAC can cause bronchopulmonary infections that can be prolonged and difficult to treat. MAC infections of sites other than the lungs or central catheters are rare and almost exclusively associated with immunodeficiency.

CASE PRESENTATION: We present a case of an 8-year-old CF patient (delF508 homozygous) with recurrent pulmonary exacerbations, gradual clinical deterioration, B-symptoms (fever, fatigue, weight loss, night sweat), elevated transaminases and intermittent detection of M. chimaera in the sputum without radiological signs of NTM-associated lung disease with a central venous port-catheter. Next-generation sequencing (NGS) revealed M. chimaera port infection that was also confirmed by mycobacterial culture. The patient recovered within 4 weeks after removal of the catheter and initiation of MAC targeted antimicrobial therapy. Electron microscopy of the catheter illustrated the presence of mycobacteria in a biofilm.

CONCLUSIONS: MAC central venous catheter infection needs to be considered in immunocompetent people. NGS is a valuable tool for rapid identification of rare infections. MAC capability of biofilm formation renders catheter removal the central therapeutic intervention for the clearance of the infection.}, } @article {pmid36494359, year = {2022}, author = {Gheorghita, AA and Li, YE and Kitova, EN and Bui, DT and Pfoh, R and Low, KE and Whitfield, GB and Walvoort, MTC and Zhang, Q and Codée, JDC and Klassen, JS and Howell, PL}, title = {Structure of the AlgKX modification and secretion complex required for alginate production and biofilm attachment in Pseudomonas aeruginosa.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {7631}, pmid = {36494359}, issn = {2041-1723}, support = {Graduate Scholarship//Cystic Fibrosis Canada (Fibrose kystique Canada)/ ; Grauate scholarship//Cystic Fibrosis Canada (Fibrose kystique Canada)/ ; Summer student award//UAlberta | Canadian Glycomics Network (GlycoNet)/ ; Graduate Scholarship//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; Operating grant//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; MOP43998//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; FDN154327//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; Tier I//Canada Research Chairs (Chaires de recherche du Canada)/ ; }, mesh = {*Pseudomonas aeruginosa/metabolism ; *Alginates/metabolism ; Hexuronic Acids/metabolism ; Bacterial Proteins/metabolism ; Glucuronic Acid/metabolism ; Biofilms ; Polymers/metabolism ; }, abstract = {Synthase-dependent secretion systems are a conserved mechanism for producing exopolysaccharides in Gram-negative bacteria. Although widely studied, it is not well understood how these systems are organized to coordinate polymer biosynthesis, modification, and export across both membranes and the peptidoglycan. To investigate how synthase-dependent secretion systems produce polymer at a molecular level, we determined the crystal structure of the AlgK-AlgX (AlgKX) complex involved in Pseudomonas aeruginosa alginate exopolysaccharide acetylation and export. We demonstrate that AlgKX directly binds alginate oligosaccharides and that formation of the complex is vital for polymer production and biofilm attachment. Finally, we propose a structural model for the AlgEKX outer membrane modification and secretion complex. Together, our study provides insight into how alginate biosynthesis proteins coordinate production of a key exopolysaccharide involved in establishing persistent Pseudomonas lung infections.}, } @article {pmid36484848, year = {2023}, author = {Shirato, M and Nakamura, K and Tenkumo, T and Niwano, Y and Kanno, T and Sasaki, K and Lingström, P and Örtengren, U}, title = {Inhibition of tooth demineralization caused by Streptococcus mutans biofilm via antimicrobial treatment using hydrogen peroxide photolysis.}, journal = {Clinical oral investigations}, volume = {27}, number = {2}, pages = {739-750}, pmid = {36484848}, issn = {1436-3771}, support = {19K19014//Japan Society for the Promotion of Science/ ; I 2017-008//Stiftelsen Patentmedelsfonden för Odontologisk Profylaxforskning/ ; I 2018-014//Stiftelsen Patentmedelsfonden för Odontologisk Profylaxforskning/ ; TUAGBG-926091//Västra Götalandsregionen/ ; }, mesh = {Animals ; Rats ; Hydrogen Peroxide/pharmacology ; *Dental Caries/microbiology ; Streptococcus mutans ; Photolysis ; Rats, Wistar ; *Tooth Demineralization/drug therapy/prevention & control ; *Anti-Infective Agents/pharmacology ; Biofilms ; }, abstract = {OBJECTIVES: An antimicrobial technique utilizing hydroxyl radicals generated by the photolysis of 3% H2O2 has been developed recently. The present study aimed to evaluate the effect of H2O2 photolysis treatment on tooth demineralization caused by Streptococcus mutans biofilm.

MATERIALS AND METHODS: To induce tooth demineralization, S. mutans biofilm was allowed to form on the maxillary first molars collected from Wistar rats via 24-h culturing. The samples were immersed in 3% H2O2 and irradiated with 365-nm LED (H2O2 photolysis treatment). Viable bacterial counts in the biofilm were evaluated immediately after treatment and after an additional 30-h culturing by colony counting. The acidogenicity of the biofilm, re-established 30 h after treatment, was assessed by measuring the pH. The effect of H2O2 photolysis treatment on tooth demineralization was assessed by measuring the depth of the radiolucent layer in micro-CT images.

RESULTS: H2O2 photolysis significantly reduced viable bacterial counts in the biofilm to 3.7 log colony forming units (CFU)/sample, while the untreated group had 7.9 log CFU/sample. The pH of the biofilm re-established after treatment (6.6) was higher than that of the untreated group (5.3). In line with the pH measurement, the treatment group had a significantly lower depth of radiolucent layer in dentin than the untreated group.

CONCLUSIONS: H2O2 photolysis treatment was effective not only in killing the biofilm-forming S. mutans but also in lowering the acidogenicity of the biofilm. Thus, this technique could inhibit tooth demineralization.

CLINICAL RELEVANCE: H2O2 photolysis can be applicable as a new dental caries treatment.}, } @article {pmid36484825, year = {2023}, author = {Pandey, P and Meher, K and Falcao, B and Lopus, M and Sirisha, VL}, title = {Tryptone-stabilized silver nanoparticles' potential to mitigate planktonic and biofilm growth forms of Serratia marcescens.}, journal = {Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry}, volume = {28}, number = {2}, pages = {139-152}, pmid = {36484825}, issn = {1432-1327}, mesh = {*Serratia marcescens/genetics ; Silver/pharmacology/chemistry ; *Metal Nanoparticles/chemistry ; Extracellular Polymeric Substance Matrix ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; Microbial Sensitivity Tests ; }, abstract = {Several microbial pathogens are capable of forming biofilms. These microbial communities pose a serious challenge to the healthcare sector as they are quite difficult to combat. Given the challenges associated with the antibiotic-based management of biofilms, the research focus has now been shifted towards finding alternate treatment strategies that can replace or complement the antibacterial properties of antibiotics. The field of nanotechnology offers several novel and revolutionary approaches to eradicate biofilm-forming microbes. In this study, we evaluated the antibacterial and antibiofilm efficacy of in-house synthesized, tryptone-stabilized silver nanoparticles (Ts-AgNPs) against the superbug Serratia marcescens. The nanoparticles were of spherical morphology with an average hydrodynamic diameter of 170 nm and considerable colloidal stability with a Zeta potential of - 24 ± 6.15 mV. Ts-AgNPs showed strong antibacterial activities with a minimum inhibitory concentration (MIC50) of 2.5 µg/mL and minimum bactericidal concentration (MBC) of 12.5 µg/mL against S. marcescens. The nanoparticles altered the cell surface hydrophobicity and inhibited biofilm formation. The Ts-AgNPs were also effective in distorting pre-existing biofilms by degrading the extracellular DNA (eDNA) component of the extracellular polymeric substance (EPS) layer. Furthermore, reduction in quorum-sensing (QS)-induced virulence factors produced by S. marcescens indicated that Ts-AgNPs attenuated the QS pathway. Together, these findings suggest that Ts-AgNPs are an important anti-planktonic and antibiofilm agent that can be explored for both the prevention and treatment of infections caused by S. marcescens.}, } @article {pmid36484349, year = {2023}, author = {Yuwen, L and Xiao, H and Lu, P and Chen, X and Li, J and Xiu, W and Gan, S and Yang, D and Wang, L}, title = {Amylase degradation enhanced NIR photothermal therapy and fluorescence imaging of bacterial biofilm infections.}, journal = {Biomaterials science}, volume = {11}, number = {2}, pages = {630-640}, doi = {10.1039/d2bm01570f}, pmid = {36484349}, issn = {2047-4849}, mesh = {Mice ; Animals ; Photothermal Therapy ; Manganese Compounds ; *Methicillin-Resistant Staphylococcus aureus ; Amylases ; Oxides ; Polyethylene Glycols/chemistry ; Indocyanine Green/chemistry ; *Bacterial Infections ; Biofilms ; alpha-Amylases ; Optical Imaging ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {Effective treatment of bacterial biofilm-related infections is a great challenge for the medical community. During the formation of biofilms, bacteria excrete extracellular polymeric substances (EPS), including polysaccharides, proteins, nucleic acids, etc., to encapsulate themselves and form a "fort-like" structure, which greatly reduces the efficiency of therapeutic agents. Herein, we prepared a nanoagent (MnO2-amylase-PEG-ICG nanosheets, MAPI NSs) with biofilm degradation capability for efficient photothermal therapy and fluorescence imaging of methicillin-resistant Staphylococcus aureus (MRSA) biofilm infections. MAPI NSs were constructed by sequentially modifying α-amylase, polyethylene glycol (PEG), and indocyanine green (ICG) on manganese dioxide nanosheets (MnO2 NSs). Experimental results exhibited that MAPI NSs could accumulate in infected tissues after intravenous injection, degrade in the acidic biofilm microenvironment, and release the loaded ICG for near-infrared (NIR) fluorescence imaging of the infected tissues. Importantly, MAPI NSs could efficiently eliminate MRSA biofilm infections in mice by α-amylase enhanced photothermal therapy. In addition, MAPI NSs exhibited neglectable toxicity towards mice. Given the superior properties of MAPI NSs, the enzyme-degradation enhanced therapeutic strategy presented in this work offers a promising solution for effectively combating biofilm infectious diseases.}, } @article {pmid36482060, year = {2022}, author = {Huber, M and Lippegaus, A and Melamed, S and Siemers, M and Wucher, BR and Hoyos, M and Nadell, C and Storz, G and Papenfort, K}, title = {An RNA sponge controls quorum sensing dynamics and biofilm formation in Vibrio cholerae.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {7585}, pmid = {36482060}, issn = {2041-1723}, mesh = {Humans ; *Vibrio cholerae/genetics ; RNA ; }, abstract = {Small regulatory RNAs (sRNAs) acting in concert with the RNA chaperone Hfq are prevalent in many bacteria and typically act by base-pairing with multiple target transcripts. In the human pathogen Vibrio cholerae, sRNAs play roles in various processes including antibiotic tolerance, competence, and quorum sensing (QS). Here, we use RIL-seq (RNA-interaction-by-ligation-and-sequencing) to identify Hfq-interacting sRNAs and their targets in V. cholerae. We find hundreds of sRNA-mRNA interactions, as well as RNA duplexes formed between two sRNA regulators. Further analysis of these duplexes identifies an RNA sponge, termed QrrX, that base-pairs with and inactivates the Qrr1-4 sRNAs, which are known to modulate the QS pathway. Transcription of qrrX is activated by QrrT, a previously uncharacterized LysR-type transcriptional regulator. Our results indicate that QrrX and QrrT are required for rapid conversion from individual to community behaviours in V. cholerae.}, } @article {pmid36481376, year = {2023}, author = {Bunse, P and Orschler, L and Pidde, AV and Lackner, S}, title = {Effects of scouring on membrane aerated biofilm reactor performance and microbial community composition.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128441}, doi = {10.1016/j.biortech.2022.128441}, pmid = {36481376}, issn = {1873-2976}, mesh = {*Bioreactors ; Wastewater ; Biofilms ; Nitrogen ; *Microbiota ; Waste Disposal, Fluid/methods ; }, abstract = {This study investigated the effects of scouring on Membrane Aerated Biofilm Reactors (MABRs). Laboratory-scale MABRs were operated under conditions typical for municipal wastewater. Scouring was induced by bubbling dinitrogen gas through the reactor bulk at low and high frequencies (LF and HF). At low nitrogen surface loads, almost complete ammonium removal was observable while HF scouring resulted in less total nitrogen (TN) removal compared to LF scouring. High nitrogen surface loads combined with HF scouring resulted in a higher TN removal as LF scouring. HF scouring resulted in around four times more sludge production and less residual biofilm mass compared to LF scouring. 16S amplicon sequencing of the biofilm, detached biomass and flocs revealed major differences between the microbial community compositions of these fractions. These results indicate that by varying the scouring strategy is a potential control mechanism for MABR operation and can help to reach specific treatment targets.}, } @article {pmid36476055, year = {2022}, author = {Liu, S and Jiang, L and Miao, H and Lv, Y and Zhang, Q and Ma, M and Duan, W and Huang, Y and Wei, X}, title = {Autophagy regulation of ATG13 and ATG27 on biofilm formation and antifungal resistance in Candida albicans.}, journal = {Biofouling}, volume = {38}, number = {9}, pages = {926-939}, doi = {10.1080/08927014.2022.2153332}, pmid = {36476055}, issn = {1029-2454}, mesh = {*Candida albicans ; *Antifungal Agents/pharmacology/metabolism ; Biofilms ; Microbial Sensitivity Tests ; Plankton/metabolism ; Transcription Factors ; Autophagy/genetics ; }, abstract = {Autophagy is a highly conserved catabolic pathway that is vital for cells; however, the effects of autophagy on the biofilm formation and antifungal resistance of Candida albicans are still unknown. In this study, the potential molecular mechanisms of autophagy in biofilm formation and antifungal resistance were investigated. It was found that 3536 genes were differentially expressed between biofilm and planktonic C. albicans. ATG gene expression and autophagy activity were higher in biofilm than in planktonic C. albicans. Autophagic activities were higher in matured biofilms than that in pre-matured biofilms. Autophagy was involved in C. albicans biofilm formation and its activity increased during biofilm maturation. Further, ALP activity, AO staining cells, and autophagosomes inside cells were obviously reduced in biofilms of atg13Δ/Δ and atg27Δ/Δ strains; moreover, biofilm formation and antifungal resistance were also significantly decreased. Lastly, autophagy regulates biofilm formation and drug resistance of C. albicans and could be served as a new molecular target to the C. albicans biofilm infections.}, } @article {pmid36474566, year = {2022}, author = {Ahmed, AA and A Salih, F and Yousef, M}, title = {Rhus coriaria extracts inhibit quorum sensing-related virulence and biofilm production in drug-resistant Pseudomonas aeruginosa recovered from burn wounds.}, journal = {Iranian journal of basic medical sciences}, volume = {25}, number = {11}, pages = {1349-1356}, pmid = {36474566}, issn = {2008-3866}, abstract = {OBJECTIVES: Numerous studies have confirmed sumac's ability to inhibit pathogens and even eradicate chronic drug-resistant infections. Current research was conducted to demonstrate the action of various sumac extracts at sub-inhibitory concentrations in modulating pathogen-related characteristics instead of killing them.

MATERIALS AND METHODS: The influence of sumac extracts on the quorum sensing dependent virulence of multidrug-resistant isolates of Pseudomonas aeruginosa recovered from burn wounds was considered by detecting the effect on biofilm development, various virulence factors, and expression of bacterial exotoxin A and quorum sensing related genes.

RESULTS: Experiments to characterize and measure sumac extract's impact on the P. aeruginosa growth, biofilm, exoproteases, pyocyanin, motility, and the quorum sensing networks revealed that all studied characteristics were reduced by concentrations below inhibition without affecting bacterial growth. Furthermore, the expression of exotoxin A, rhl, and las glucons was declined or even inhibited by lower levels of sumac fruit fractions.

CONCLUSION: The findings revealed that sumac fights infections either by its inhibitory effect on the bacterial cells or by reducing bacterial signaling and virulence by disruption of the bacterial signal system.}, } @article {pmid36473894, year = {2022}, author = {Cavallo, I and Sivori, F and Truglio, M and De Maio, F and Lucantoni, F and Cardinali, G and Pontone, M and Bernardi, T and Sanguinetti, M and Capitanio, B and Cristaudo, A and Ascenzioni, F and Morrone, A and Pimpinelli, F and Di Domenico, EG}, title = {Skin dysbiosis and Cutibacterium acnes biofilm in inflammatory acne lesions of adolescents.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {21104}, pmid = {36473894}, issn = {2045-2322}, mesh = {Humans ; Adolescent ; *Acne Vulgaris ; }, abstract = {Acne vulgaris is a common inflammatory disorder affecting more than 80% of young adolescents. Cutibacterium acnes plays a role in the pathogenesis of acne lesions, although the mechanisms are poorly understood. The study aimed to explore the microbiome at different skin sites in adolescent acne and the role of biofilm production in promoting the growth and persistence of C. acnes isolates. Microbiota analysis showed a significantly lower alpha diversity in inflammatory lesions (LA) than in non-inflammatory (NI) lesions of acne patients and healthy subjects (HS). Differences at the species level were driven by the overabundance of C. acnes on LA than NI and HS. The phylotype IA1 was more represented in the skin of acne patients than in HS. Genes involved in lipids transport and metabolism, as well as potential virulence factors associated with host-tissue colonization, were detected in all IA1 strains independently from the site of isolation. Additionally, the IA1 isolates were more efficient in early adhesion and biomass production than other phylotypes showing a significant increase in antibiotic tolerance. Overall, our data indicate that the site-specific dysbiosis in LA and colonization by virulent and highly tolerant C. acnes phylotypes may contribute to acne development in a part of the population, despite the universal carriage of the microorganism. Moreover, new antimicrobial agents, specifically targeting biofilm-forming C. acnes, may represent potential treatments to modulate the skin microbiota in acne.}, } @article {pmid36473584, year = {2023}, author = {Li, J and Ali, A and Su, J and Huang, T and Zhai, Z and Xu, L}, title = {Synergistic removal of nitrate by a cellulose-degrading and denitrifying strain through iron loaded corn cobs filled biofilm reactor at low C/N ratio: Capability, enhancement and microbiome analysis.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128433}, doi = {10.1016/j.biortech.2022.128433}, pmid = {36473584}, issn = {1873-2976}, mesh = {*Nitrates/metabolism ; Zea mays/metabolism ; Denitrification ; Cellulose ; Iron ; *Microbiota ; Biofilms ; Bioreactors/microbiology ; Nitrogen/metabolism ; }, abstract = {Optimization of nitrate removal rate under low carbon-to-nitrogen ratio has always been one of the research hotspots. Biofilm reactor based on functional carrier and using interspecific synergic effect of strains provides an insight. In this study, iron-loaded corn cob was used as a functional carrier that can contribute to the cellulose degradation, iron cycling, and collaborative denitrification process of microorganisms. During biofilm reactor operation, the maximum nitrate removal efficiency was 99.30% and could reach 81.73% at no carbon source. Dissolved organic carbon and carrier characterization showed that strain ZY7 promoted the release of carbon source. The crystallinity of cellulose I and II in carrier of experimental group increased by 31.26% and decreased by 21.83%, respectively, in comparison to the control group. Microbial community showed the synergistic effect among different strains. The vitality and metabolic activity of the target microorganisms in bioreactor were increased through interspecific bacterial cooperation.}, } @article {pmid36472682, year = {2022}, author = {Park, J and Choi, Y and Kim, SD}, title = {Distribution and transformation of organophosphate esters in moving bed biofilm reactor.}, journal = {Environmental geochemistry and health}, volume = {}, number = {}, pages = {}, pmid = {36472682}, issn = {1573-2983}, support = {NRF-2021R1A2C1006509//National Research Foundation of Korea (NRF)/ ; }, abstract = {A moving bed biofilm reactor (MBBR) process in wastewater treatment plants (WWTPs) uses plastic carriers, called biofilm carrier, to increase their treatment efficiency. Biofilm carrier is made up of plastic, containing the OPEs as flame retardants or plasticizers, so OPEs in biofilm carrier are possible to release from WWTPs to the river. This study investigated the effect of the MBBR process in WWTP on aquatic environments, focusing on OPEs. OPE eluted from the biofilm carrier by leaching test was tris(2-chloroethyl) phosphate (TCEP), and the concentration of the effluent compared to the influent was increased in the WWTP of the MBBR process. 3609 mg/day of TCEP would be discharged into the water using the second-order model with rate constant [Formula: see text] = 0.000451 (ng L[-1])[-1] h[-1], which is the most suitable for the leaching concentration of TCEP. It was identified that TCEP in biofilm carrier was transformed into oxidative dechlorinated compounds and oxidative compounds by microorganisms in the bioreactor. As a result of the study, it was confirmed that not only TCEP but also transformation products of TCEP emitted into the water from the MBBR process of WWTP.}, } @article {pmid36472442, year = {2023}, author = {Palau, M and Muñoz, E and Larrosa, N and Gomis, X and Márquez, E and Len, O and Almirante, B and Gavaldà, J}, title = {Hyperthermia Prevents In Vitro and In Vivo Biofilm Formation on Endotracheal Tubes.}, journal = {Microbiology spectrum}, volume = {11}, number = {1}, pages = {e0280722}, pmid = {36472442}, issn = {2165-0497}, mesh = {Humans ; Animals ; Rabbits ; *Methicillin-Resistant Staphylococcus aureus ; Intubation, Intratracheal/adverse effects ; Anti-Bacterial Agents ; *Pneumonia, Ventilator-Associated/etiology/prevention & control ; Biofilms ; Pseudomonas aeruginosa ; *Hyperthermia, Induced/adverse effects ; }, abstract = {There is currently an urgent need to find new strategies to tackle antimicrobial resistance and biofilm-related infections. This study has two aims. First, we evaluated the in vitro efficacy of hyperthermia in preventing biofilm formation on the surfaces of polyvinyl chloride discs. Second, we assessed the in vivo efficacy of hyperthermia in preventing biofilm formation in endotracheal tubes (ETTs) of a rabbit model. For the in vitro studies, nine clinical extensively drug-resistant/multidrug-resistant Gram-negative isolates of Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa and three clinical methicillin-resistant Staphylococcus aureus strains were studied. For biofilm formation, an adhesion step of 30 or 90 min followed by a growth step of 24 h were performed with application of one, two, and three pulses at 42°C for 15 min each pulse after the adhesion step. For the in vivo studies, New Zealand rabbits were intubated with ETTs previously colonized with K. pneumoniae or P. aeruginosa strains, and three pulses at 42°C for 15 min were applied after the adhesion step. The application of three pulses at 42°C for 15 min each pulse was needed to achieve the prevention of the in vitro biofilm formation of 100% of the tested strains. The application of heat pulses in a rabbit intubation model led to biofilm prevention of 85% against two K. pneumoniae strains and 80% against two P. aeruginosa strains compared to the control group. Hyperthermia application through pulses at 42°C could be a new nonantibiotic strategy to prevent biofilm formation in ETTs. IMPORTANCE Biofilm-producing microorganisms are considered medically crucial since they cause 80% of the infections that occur in the human body. Medical devices such as endotracheal tubes (ETTs) can act as a reservoir for pathogens providing the surface to which microorganisms can adhere and cause biofilm-associated infections in critically ill patients. This biofilm has been related with the development of ventilator-associated pneumonia (VAP), with an incidence of 8 to 28%, a mortality rate up to 17% and its associated high extra costs. Although some VAP-preventive measures have been reported, they have not demonstrated a significant reduction of VAP incidence. Therefore, we present a new nonantibiotic strategy based on hyperthermia application to prevent biofilm formation inside ETTs. This technology could reduce VAP incidence, intubation duration, hospital and intensive care unit (ICU) length stays, and mortality rates. Consequently, this could decrease the antibiotics administered and influence the impact of antibiotic resistance in the ICU.}, } @article {pmid36470671, year = {2023}, author = {Lv, X and Wang, L and Mei, A and Xu, Y and Ruan, X and Wang, W and Shao, J and Yang, D and Dong, X}, title = {Recent Nanotechnologies to Overcome the Bacterial Biofilm Matrix Barriers.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {19}, number = {6}, pages = {e2206220}, doi = {10.1002/smll.202206220}, pmid = {36470671}, issn = {1613-6829}, mesh = {Humans ; Extracellular Polymeric Substance Matrix/metabolism ; Biofilms ; Drug Delivery Systems ; *Nanoparticles ; *Bacterial Infections/metabolism ; Nanotechnology ; }, abstract = {Bacterial biofilm-related infectious diseases severely influence human health. Under typical situations, pathogens can colonize inert or biological surfaces and form biofilms. Biofilms are functional aggregates that coat bacteria with extracellular polymeric substances (EPS). The main reason for the failure of biofilm infection treatment is the low permeability and enrichment of therapeutic agents within the biofilm, which results from the particular features of biofilm matrix barriers such as negatively charged biofilm components and highly viscous compact EPS structures. Hence, developing novel therapeutic strategies with enhanced biofilm penetrability is crucial. Herein, the current progress of nanotechnology methods to improve therapeutic agents' penetrability against biofilm matrix, such as regulating material morphology and surface properties, utilizing the physical penetration of nano/micromotors or microneedle patches, and equipping nanoparticles with EPS degradation enzymes or signal molecules, is first summarized. Finally, the challenges, perspectives, and future implementations of engineered delivery systems to manage biofilm infections are presented in detail.}, } @article {pmid36470489, year = {2023}, author = {Pang, S and Zhou, Y and Yang, L and Zhou, J and Li, X and Xia, S}, title = {Simultaneous removal of nitrate and ammonium by hydrogen-based partial denitrification coupled with anammox in a membrane biofilm reactor.}, journal = {Bioresource technology}, volume = {369}, number = {}, pages = {128443}, doi = {10.1016/j.biortech.2022.128443}, pmid = {36470489}, issn = {1873-2976}, mesh = {*Nitrates ; *Ammonium Compounds ; Denitrification ; Anaerobic Ammonia Oxidation ; Bioreactors ; Oxidation-Reduction ; Anaerobiosis ; Methane ; Biofilms ; Nitrogen ; }, abstract = {Hydrogen-based membrane biofilm reactors (MBfRs) are effective for nitrogen removal. However, the safety of hydrogen limited the application of MBfR. Here, a hydrogen-based partial denitrification system coupled with anammox (H2-PDA) was constructed in an MBfR for reducing hydrogen demand significantly. The metabolomics and structures of microbial communities were analyzed to determine the phenotypic differences and drivers underlying denitrification, anammox, and H2-PDA. These findings indicated that total nitrogen (TN) removal increased from 57.1% in S1 to 93.7% in S2. During the H2-PDA process, partial denitrification and anammox contributed to TN removal by 93.7% and 6.3%, respectively. Community analysis indicated that the H2-PDA system was dominated by the genus Meiothermus, which is involved in partial denitrification. Collectively, these findings confirmed the feasibility of incorporating the H2-PDA process in a MBfR and form a foundation for the establishment of novel and practical methods for efficient nitrogen removal.}, } @article {pmid36470486, year = {2023}, author = {Has, EG and Akçelik, N and Akçelik, M}, title = {Comparative global gene expression analysis of biofilm forms of Salmonella Typhimurium ATCC 14028 and its seqA mutant.}, journal = {Gene}, volume = {853}, number = {}, pages = {147094}, doi = {10.1016/j.gene.2022.147094}, pmid = {36470486}, issn = {1879-0038}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; *MicroRNAs/metabolism ; *Salmonella typhimurium/genetics ; }, abstract = {In this study, comparative transcriptomic analyzes (mRNA and miRNA) were performed on the biofilm forms of S. Typhimurium ATCC 14028 wild-type strain and its seqA gene mutant in order to determine the regulation characteristics of the seqA gene in detail. The results of global gene expression analyses showed an increase in the expression level of 54 genes and a decrease in the expression level of 155 genes (p < 0.05) in the seqA mutant compared to the wild-type strain. 10 of the 48 miRNAs identified on behalf of sequence analysis are new miRNA records for Salmonella. Transcripts of 14 miRNAs differed between wild-type strain and seqA mutant (p < 0.05), of which eight were up-regulated and six were down-regulated. Bioinformatic analyzes showed that differentially expressed genes in the wild-type strain and its seqA gene mutant play a role in different metabolic processes as well as biofilm formation, pathogenicity and virulence. When the transcriptomic data were interpreted together with the findings obtained from phenotypic tests such as motility, attachment to host cells and biofilm morphotyping, it was determined that the seqA gene has a critical function especially for the adhesion and colonization stages of biofilm formation, as well as for biofilm stability. Transcriptomic data pointing out that the seqA gene is also a general positive regulator of T3SS effector proteins active in cell invasion in S. Typhimurium wild-type biofilm, proves that this gene is involved in Salmonella host cell invasion.}, } @article {pmid36469275, year = {2023}, author = {Liu, C and Zhang, L and Yu, H and Zhang, H and Niu, H and Gai, J}, title = {Bioreduction of Cr(VI) using a propane-based membrane biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {12}, pages = {32683-32695}, pmid = {36469275}, issn = {1614-7499}, mesh = {*Extracellular Polymeric Substance Matrix/metabolism ; *Propane ; Oxidation-Reduction ; Chromium/metabolism ; Biofilms ; }, abstract = {The strong physiological toxicity of Cr(VI) makes it widely concerned in wastewater treatment. At present, the simplest and harmless method for treating Cr(VI) is known to be biologically reducing it to Cr(III), making it precipitate as Cr(OH)3(s), and then removing Cr(III) by solid separation technology. Studies have shown that Cr(VI) reduction bacteria can use CH4 and H2 as electron donors to reduce Cr(VI). Based on this, in this study, C3H8 was used as the only electron donor to investigate the potential of C3H8 matrix membrane bioreactor in the Cr(VI) wastewater treatment. The experiment was divided into three stages, each of which run stably for at least 30 days, and the whole process run for 120 days in total. The experiment is divided into three stages, each stage runs stably for at least 30 days, for a total of 120 days. With the increase of the Cr(VI) load, the removal rate gradually decreased. In stage 3, when Cr(VI) concentration was 2.0 mg·L[-1], the removal rate was reduced from 90% in the first stage to 75%. According to X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis, it is known that Cr(III) is the main product during this process and it is adsorbed on the biofilm as Cr(OH)3 precipitate. During the experiment, the amount of extracellular polymeric substance (EPS) produced by microorganisms increased initially and then decreased, and the amount of polysaccharides (PS) was always more than protein (PN). By analyzing the microbial community structure after inoculating sludge and adding Cr(VI), Nocardia and Rhodococcus dominate the biofilm samples. Chromate reductase, cytochrome c, nitrate reductase, and other functional genes related to chromate reductase increased gradually during the experiment.}, } @article {pmid36467736, year = {2022}, author = {Ye, Z and Ye, L and Li, D and Lin, S and Deng, W and Zhang, L and Liang, J and Li, J and Wei, Q and Wang, K}, title = {Effects of daphnetin on biofilm formation and motility of pseudomonas aeruginosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1033540}, pmid = {36467736}, issn = {2235-2988}, mesh = {Humans ; *Pseudomonas aeruginosa ; *Pyocyanine ; Umbelliferones/pharmacology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {INTRODUCTION: Pseudomonas aeruginosa is a common clinical opportunistic pathogen. Antibiotic resistance of P. aeruginosa is frequent, and it affects the clinical curative effect and leads to recurrent infections, disease progression, and difficult treatment, especially in cystic fibrosis patients. The drug-resistance mechanism of P. aeruginosa is complex, and biofilms play an important role. Given the widespread antibiotic resistance of P. aeruginosa, the discovery of a drug that can prevent or eradicate biofilm formation is imperative. Daphnetin (DAP), a coumarin derivative, is a safe, non-toxic, natural compound with antibacterial and anti-biofilm properties. Herein, this study highlights the bacterial motility effects, antibacterial effect, pyocyanin production, and anti-biofilm potential of DAP against P. aeruginosa.

METHODS: In this study, the minimal inhibitory concentration of DAP against P. aeruginosa was determined using the microdilution method. The antibiofilm activity of DAP against P. aeruginosa was determined using crystal violet staining, colony-forming unit enumeration, and scanning electron microscopy. The effect of DAP on P. aeruginosa motility was detected using the swimming, swarming, and twitching agar plates to measure the diameter of the concentric area.

RESULTS: We found that DAP at concentrations of 0.445-1.781 mg/mL and 0.89-1.781 mg/mL can effectively inhibit biofilm formation and eradicate the formed biofilm of P. aeruginosa, respectively. DAP reduced pyocyanin production and inhibited bacterial motility of P. aeruginosa.

DISCUSSION: In conclusion, our results support the conclusion that DAP can effectively eradicate formed biofilm and inhibit biofilm formation, bacterial motility, and pyocyanin production of P. aeruginosa and may represent a natural anti-biofilm therapeutic agent.}, } @article {pmid36466653, year = {2022}, author = {Rubio-Canalejas, A and Baelo, A and Herbera, S and Blanco-Cabra, N and Vukomanovic, M and Torrents, E}, title = {3D spatial organization and improved antibiotic treatment of a Pseudomonas aeruginosa-Staphylococcus aureus wound biofilm by nanoparticle enzyme delivery.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {959156}, pmid = {36466653}, issn = {1664-302X}, abstract = {Chronic wounds infected by Pseudomonas aeruginosa and Staphylococcus aureus are a relevant health problem worldwide because these pathogens grow embedded in a network of polysaccharides, proteins, lipids, and extracellular DNA, named biofilm, that hinders the transport of antibiotics and increases their antimicrobial tolerance. It is necessary to investigate therapies that improve the penetrability and efficacy of antibiotics. In this context, our main objectives were to study the relationship between P. aeruginosa and S. aureus and how their relationship can affect the antimicrobial treatment and investigate whether functionalized silver nanoparticles can improve the antibiotic therapy. We used an optimized in vitro wound model that mimics an in vivo wound to co-culture P. aeruginosa and S. aureus biofilm. The in vitro wound biofilm was treated with antimicrobial combinatory therapies composed of antibiotics (gentamycin and ciprofloxacin) and biofilm-dispersing free or silver nanoparticles functionalized with enzymes (α-amylase, cellulase, DNase I, or proteinase K) to study their antibiofilm efficacy. The interaction and colocalization of P. aeruginosa and S. aureus in a wound-like biofilm were examined and detailed characterized by confocal and electronic microscopy. We demonstrated that antibiotic monotherapy is inefficient as it differentially affects the two bacterial species in the mixed biofilm, driving P. aeruginosa to overcome S. aureus when using ciprofloxacin and the contrary when using gentamicin. In contrast, dual-antibiotic therapy efficiently reduces both species while maintaining a balanced population. In addition, DNase I nanoparticle treatment had a potent antibiofilm effect, decreasing P. aeruginosa and S. aureus viability to 0.017 and 7.7%, respectively, in combined antibiotics. The results showed that using nanoparticles functionalized with DNase I enhanced the antimicrobial treatment, decreasing the bacterial viability more than using the antibiotics alone. The enzymes α-amylase and cellulase showed some antibiofilm effect but were less effective compared to the DNase I treatment. Proteinase K showed insignificant antibiofilm effect. Finally, we proposed a three-dimensional colocalization model consisting of S. aureus aggregates within the biofilm structure, which could be associated with the low efficacy of antibiofilm treatments on bacteria. Thus, designing a clinical treatment that combines antibiofilm enzymes and antibiotics may be essential to eliminating chronic wound infections.}, } @article {pmid36466220, year = {2023}, author = {Hamza, EH and El-Shawadfy, AM and Allam, AA and Hassanein, WA}, title = {Study on pyoverdine and biofilm production with detection of LasR gene in MDR Pseudomonas aeruginosa.}, journal = {Saudi journal of biological sciences}, volume = {30}, number = {1}, pages = {103492}, pmid = {36466220}, issn = {1319-562X}, abstract = {In cystic fibrosis individuals, chronic lung infections and hospital-acquired pneumonia are caused by Pseudomonas aeruginosa. P. aeruginosa generates siderophores such as pyoverdine (PVD) as iron uptake systems to cover its needs of iron ions for growth and infection. lasR quorum sensing (QS) gene has a crucial function in PVD production and biofilm generation in P. aeruginosa. Fifty isolates of P. aeruginosa were obtained from clinical specimens of sputum (collected from individuals suffering from pulmonary infections). Antibiotic sensitivity test was performed for 50P. aeruginosa isolates by using 10 different types of antibiotics. All isolates of P. aeruginosa showed resistance for all 10 using antibiotics in this study. Ten multidrug resistant isoloates of P. aeruginosa were selected for next tests. Virulence factors of ten multidrug resistant isolates of P. aeruginosa, such as biofilm generation, PVD production, and lasR gene were detected. From results, all 10P. aeruginosa isolates can produce biofilm, PVD, and contain lasR gene. The produced amplicon for the lasR gene was 725 bp. After mice injection by fresh and heated PVD produced by P. aeruginosa PS10 LC619328.2, the fresh PVD caused 100 % mortality within five days using 0.3 ml of its concentration (37.4 µM), while (15.3 µM) of heated PVD (toxoid) caused 50 % mortality.}, } @article {pmid36464983, year = {2023}, author = {Alonso, VPP and Gonçalves, MPMBB and de Brito, FAE and Barboza, GR and Rocha, LO and Silva, NCC}, title = {Dry surface biofilms in the food processing industry: An overview on surface characteristics, adhesion and biofilm formation, detection of biofilms, and dry sanitization methods.}, journal = {Comprehensive reviews in food science and food safety}, volume = {22}, number = {1}, pages = {688-713}, doi = {10.1111/1541-4337.13089}, pmid = {36464983}, issn = {1541-4337}, mesh = {*Food-Processing Industry ; *Biofilms ; Food Microbiology ; Food Handling/methods ; Bacteria ; }, abstract = {Bacterial biofilm formation in low moisture food processing (LMF) plants is related to matters of food safety, production efficiency, economic loss, and reduced consumer trust. Dry surfaces may appear dry to the naked eye, however, it is common to find a coverage of thin liquid films and microdroplets, known as microscopic surface wetness (MSW). The MSW may favor dry surface biofilm (DSB) formation. DSB formation is similar in other industries, it occurs through the processes of adhesion, production of extracellular polymeric substances, development of microcolonies and maturation, it is mediated by a quorum sensing (QS) system and is followed by dispersal, leading to disaggregation. Species that survive on dry surfaces develop tolerance to different stresses. DSB are recalcitrant and contribute to higher resistance to sanitation, becoming potential sources of contamination, related to the spoilage of processed products and foodborne disease outbreaks. In LMF industries, sanitization is performed using physical methods without the presence of water. Although alternative dry sanitizing methods can be efficiently used, additional studies are still required to develop and assess the effect of emerging technologies, and to propose possible combinations with traditional methods to enhance their effects on the sanitization process. Overall, more information about the different technologies can help to find the most appropriate method/s, contributing to the development of new sanitization protocols. Thus, this review aimed to identify the main characteristics and challenges of biofilm management in low moisture food industries, and summarizes the mechanisms of action of different dry sanitizing methods (alcohol, hot air, UV-C light, pulsed light, gaseous ozone, and cold plasma) and their effects on microbial metabolism.}, } @article {pmid36464292, year = {2023}, author = {Matos, AO and Rangel, EC and Barão, VAR and Gregory, RL}, title = {Antimicrobial behavior of titanium coating with chlorhexidine-doped thin film exposed to a biofilm supplemented with nicotine.}, journal = {Dental materials journal}, volume = {42}, number = {2}, pages = {228-235}, doi = {10.4012/dmj.2022-168}, pmid = {36464292}, issn = {1881-1361}, mesh = {*Chlorhexidine/pharmacology ; Titanium/pharmacology/chemistry ; Nicotine/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Fusobacterium nucleatum ; }, abstract = {Because nicotine upregulates the growth of most oral bacteria, this in vitro study investigated the antimicrobial effect of chlorhexidine-doped thin film on commercially pure titanium against Fusobacterium nucleatum (F. nucleatum) biofilm supplemented with different concentrations of nicotine (0, 1, and 2 mg/mL). Biofilms were formed on a chlorhexidine-doped thin film on commercially-pure-titanium discs and compared to the control groups. Biofilm viability, total biofilm growth using a spectrophotometer, extracellular polysaccharide content, and pH variations were assessed as dependent variables. Data were submitted to ANOVA and Tukey honest significant difference tests (α=0.05). F. nucleatum biofilm growth was inhibited when exposed to chlorhexidine-doped thin film (p<0.05). Biofilm supplemented with nicotine did not impact the synthesis of EPS on the same type of treatment (p>0.05). The pH values were significantly increased with the increase of nicotine concentration (p<0.05). Chlorhexidine-doped thin film was effective in reducing F. nucleatum biofilm supplemented with nicotine.}, } @article {pmid36464290, year = {2023}, author = {Yu, W and Ren, C and Zhang, N and Cao, L and Weir, MD and Yang, K and Xu, HHK and Bai, Y}, title = {Dual function of anti-biofilm and modulating biofilm equilibrium of orthodontic cement containing quaternary ammonium salt.}, journal = {Dental materials journal}, volume = {42}, number = {2}, pages = {149-157}, doi = {10.4012/dmj.2022-142}, pmid = {36464290}, issn = {1881-1361}, mesh = {Humans ; *Dental Caries/prevention & control ; Dental Cements/pharmacology ; Glass Ionomer Cements/pharmacology ; Methacrylates/pharmacology ; Biofilms ; Streptococcus mutans ; Anti-Bacterial Agents/pharmacology ; *Ammonium Compounds ; }, abstract = {The objectives of this study were to incorporate dimethylaminohexadecyl methacrylate (DMAHDM) into resin-modified glass ionomer cement (RMGI) to develop a novel orthodontic cement which endowed RMGI with strong antibacterial ability and investigated its modulation biofilm equilibrium from cariogenic state to non-cariogenic state for the first time. Cariogenic Streptococcus mutans (S. mutans), and non-cariogenic Streptococcus sanguinis (S. sanguinis) and Streptococcus gordonii (S. gordonii) were selected to form a tri-species biofilm model. RMGI incorporated with different mass fraction of DMAHDM was examined: biofilm colony-forming units, metabolic activity, live/dead staining, lactic acid and exopolysaccharides productions. TaqMan real-time polymerase chain reaction was used to determine changes of biofilm species compositions. The results showed RMGI containing 3% DMAHDM achieved strong antibacterial ability and suppressed the cariogenic species in biofilm, modulating biofilm equilibrium from cariogenic state to non-cariogenic state tendency. The novel bioactive cement containing DMAHDM is promising in fixed orthodontic treatments and protecting tooth enamel.}, } @article {pmid36463932, year = {2023}, author = {Hartman, TW and Radichev, E and Ali, HM and Alaba, MO and Hoffman, M and Kassa, G and Sani, R and Gadhamshetty, V and Ragi, S and Messerli, SM and de la Puente, P and Sandhurst, ES and Do, T and Lushbough, C and Gnimpieba, EZ}, title = {BASIN: A Semi-automatic Workflow, with Machine Learning Segmentation, for Objective Statistical Analysis of Biomedical and Biofilm Image Datasets.}, journal = {Journal of molecular biology}, volume = {435}, number = {2}, pages = {167895}, pmid = {36463932}, issn = {1089-8638}, support = {P20 GM103443/GM/NIGMS NIH HHS/United States ; P20 RR016479/RR/NCRR NIH HHS/United States ; }, mesh = {*Image Processing, Computer-Assisted/methods ; *Machine Learning ; *Software ; Workflow ; *Biofilms ; Datasets as Topic ; *Biological Science Disciplines/methods ; }, abstract = {Micrograph comparison remains useful in bioscience. This technology provides researchers with a quick snapshot of experimental conditions. But sometimes a two- condition comparison relies on researchers' eyes to draw conclusions. Our Bioimage Analysis, Statistic, and Comparison (BASIN) software provides an objective and reproducible comparison leveraging inferential statistics to bridge image data with other modalities. Users have access to machine learning-based object segmentation. BASIN provides several data points such as images' object counts, intensities, and areas. Hypothesis testing may also be performed. To improve BASIN's accessibility, we implemented it using R Shiny and provided both an online and offline version. We used BASIN to process 498 image pairs involving five bioscience topics. Our framework supported either direct claims or extrapolations 57% of the time. Analysis results were manually curated to determine BASIN's accuracy which was shown to be 78%. Additionally, each BASIN version's initial release shows an average 82% FAIR compliance score.}, } @article {pmid36462819, year = {2023}, author = {Ban, GH and Lee, JI and Kang, DH}, title = {Effects of storage temperature on microbiota shifts in raw milk biofilm developed on stainless steel.}, journal = {Food microbiology}, volume = {110}, number = {}, pages = {104163}, doi = {10.1016/j.fm.2022.104163}, pmid = {36462819}, issn = {1095-9998}, mesh = {Animals ; *Stainless Steel ; Temperature ; Milk ; Biofilms ; *Microbiota ; }, abstract = {This study aimed to investigate the microbiota in raw milk and the influence of storage temperature on the microbiota shift after biofilm formation. Raw milk stored at 4 °C and biofilms developed in raw milk incubated at 4 °C or 25 °C for 7 days were subjected to microbiota analysis as well as quantitative analyses of aerobic or anaerobic bacteria. The levels of aerobic bacteria increased during biofilm formation, while no significant changes were observed within anaerobic bacteria. In addition, there was a difference between aerobic and anaerobic bacterial counts in raw milk and biofilm stored for 7 days. The pattern of microbial composition differed by temperature. In addition, the genus Pseudomonas (53-71%) occupied a high proportion in raw milk, and the raw milk biofilm developed at 4 °C, while the genus Lactobacillus (75-83%) was predominant in biofilms developed at 25 °C. Intriguingly, bacterial richness was higher in raw milk on day 0 and biofilm developed at 4 °C than raw milk after 7 days of storage at 4 °C. These findings suggest that temperature critically affects the bacterial composition of both raw milk and its associated biofilm.}, } @article {pmid36462590, year = {2023}, author = {Ge, G and Wu, L and Zhang, F and Wang, T and Han, L and Kong, X and Shi, J}, title = {Na2S2O4@Co-metal organic framework (ZIF-67) @glucose oxidase for biofilm-infecting wound healing with immune activation.}, journal = {International journal of biological macromolecules}, volume = {226}, number = {}, pages = {1533-1546}, doi = {10.1016/j.ijbiomac.2022.11.265}, pmid = {36462590}, issn = {1879-0003}, mesh = {*Metal-Organic Frameworks/pharmacology ; Glucose Oxidase ; Hydrogen Peroxide/pharmacology ; Wound Healing ; *Anti-Infective Agents/pharmacology ; Ions/pharmacology ; }, abstract = {In recent years, photodynamic therapy (PDT) or chemodynamic therapy (CDT) based on the antimicrobial property or anti-biofilm property of reactive oxygen species (ROS) have been widely recognized for their low susceptibility to microbial resistance. However, due to the complication of the three-dimensional structure of the biofilm at the wound site and the high quenching rate of common ROS, the treatment with traditional ROS could not achieve satisfactory wound healing effects. Here, Na2S2O8@ZIF-67/GOx nanoparticles (NZG NPs) were prepared as a new high-toxic ROS nanogenerator for application of biofilm-infecting wound healing with the assistance of glucose oxidase (GOx) for amplified CDT and immune activation. When the NZG NPs entered the biofilm, Co-based metal organic frame (ZIF-67) ruptured in the acidic microenvironment, which induced the release of GOx and the production of gluconic acid and H2O2, further promoting the decrease of pH of the biofilm microenvironment and in turn accelerating the cleavage of ZIF-67 and the release of Na2S2O8. Then, S2O8[2-] could gradually transformed into high-toxic sulfate radical (SO4[-]), part of which further produced OH in situ with H2O, thereby inhibiting the proliferation of bacteria and biofilms. Interestingly, these two types of ROS not only caused direct damage to the biofilm, but also activated the immune system of the wound site as well as the body more effectively, which also played an indirect role in promoting biofilm destruction and wound healing. In vitro and in vivo results showed that, as a new high-toxic ROS nanogenerator, the NZG NPs supply amplified chemodynamic therapy and immune activation to destroy biofilms, but also achieve effective wound healing without causing bacterial tolerance, which provides a new strategy for the development of biofilm-infecting wound healing.}, } @article {pmid36462110, year = {2023}, author = {Li, C and Wang, D and Zhou, Y and Kang, K and Ge, Y}, title = {Antifungal Activity of Camelus-Derived LFA-LFC Chimeric Peptide Gelatin Film and Effect on Oral Bacterial Biofilm.}, journal = {Applied biochemistry and biotechnology}, volume = {195}, number = {5}, pages = {2993-3010}, pmid = {36462110}, issn = {1559-0291}, support = {2018M631887//Postdoctoral Science Foundation of China/ ; }, mesh = {Animals ; *Antifungal Agents/pharmacology ; *Gelatin/chemistry ; Camelus ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; Peptides/pharmacology ; }, abstract = {The objective of this study was to construct lactoferrin (LFA-LFC) chimeric peptide gelatin drug-loaded fiber film by tissue engineering strategy, and study its bacteriostatic effect on oral pathogens (especially Candida albicans) and its effect on biofilm. First of all, LFA-LFC chitosan nanoparticles were prepared firstly, and then fluconazole gelatin (LF/GH/F) film loaded with LFA-LFC was prepared by electrospinning. Scanning electron microscope (SEM), mechanical strength, drug release, cytotoxicity, and real-time PCR were used to test the properties of the synthesized materials. SEM showed that there was the reticular structure for fiber film before and after cross-linking. LF/GH/F film had no obvious cytotoxicity, with good biocompatibility and drug release; real-time PCR and antibacterial test showed that the LF/GH/F film had good antibacterial activity. LF/GH/F film has a good inhibitory effect on oral pathogens, and its mechanism is related to biofilm. The antibacterial experiments of nanofiber membrane in vitro and the effect of bacterial biofilm were carried out. The effect of LF/GH/F on oral microbial flora structure was studied by fluorescence quantitative pest techniques.}, } @article {pmid36461626, year = {2022}, author = {Yin, H and Lin, X and Zhao, F and Pu, Y and Chen, Y and Tang, X}, title = {Nano-α-Fe2 O3 for enhanced denitrification in a heterotrophic/biofilm-electrode autotrophic denitrification reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {94}, number = {12}, pages = {e10814}, doi = {10.1002/wer.10814}, pmid = {36461626}, issn = {1554-7531}, mesh = {*Nitrates ; *Denitrification ; Ferric Compounds ; Electrodes ; Biofilms ; }, abstract = {In this study, a heterotrophic/biofilm-electrode autotrophic denitrification reactor (HAD-BER) was constructed and nano-ɑ-Fe2 O3 was coated on granular activated carbon (GAC) as a third electrode to enhance the nitrate removal performance. The introduction of nano-ɑ-Fe2 O3 could stimulate microorganisms to secrete more extracellular polymeric substances (EPS), accelerating the electron transfer. Moreover, more denitrification bacteria were enriched on the particle electrodes, especially Pseudomonas and Thermomonas, which played a significant role in denitrification. The denitrification performance at different COD/N ratios (0.65-3.23) and current intensities (0-150 mA) was investigated in depth. When the nitrate concentration of the influent was 60 mg/L, nitrate was almost completely removed at the optimal current intensity (60 mA) and COD/N ratio (1.29). At the same time, there was almost no nitrite (<0.10 mg/L) and ammonia nitrogen (0 mg/L) accumulation in the effluent. This study provided a new direction for the advancement of HAD-BER and accelerated its implementation. PRACTITIONER POINTS: By introducing nano-a-Fe2O3 into HAD-BER, more denitrification bacteria were enriched on the particle electrodes. The increased contents of polysaccharide and protein content could accelerate the electron transfer. Almost completely denitrification could be achieved at current = 60 mA and COD/N = 1.29. The study provided a new direction for the further development of HAD-BERs.}, } @article {pmid36459890, year = {2023}, author = {Liu, Q and Li, J and Zhao, Y and Li, X and Zhang, Q and Sui, J and Wang, C and Peng, Y}, title = {Mechanism of suspended sludge impact on anammox enrichment in anoxic biofilm through long term operation and microbial analysis.}, journal = {Water research}, volume = {229}, number = {}, pages = {119412}, doi = {10.1016/j.watres.2022.119412}, pmid = {36459890}, issn = {1879-2448}, mesh = {*Sewage/microbiology ; *Denitrification ; Anaerobic Ammonia Oxidation ; Nitrogen Dioxide ; Reproducibility of Results ; Bioreactors/microbiology ; Oxidation-Reduction ; Anaerobiosis ; Bacteria ; Biofilms ; Nitrogen ; }, abstract = {The basic premise of anammox-technical application reliability in municipal wastewater treatment is substantially enriched anammox bacteria. To enrich the anammox, the special interaction mechanism between the suspended sludge (SS) and anoxic biofilm was investigated over three months in a partial denitrification/anammox biosystem subjected to dynamic changes in SS (absence→ presence→ absence). Results show that the introduction of SS significantly decreased the anammox nitrogen removal efficiency (83.8 ± 6.5%→ 48.7 ± 17.0%). With the presence or absence of SS, the spatial distribution of anammox bacteria within the anoxic biofilm gradually changed between the inner and outer layers, as detected by CLSM-FISH. qPCR and metagenomic sequencing show that changes in the presence and absence status of SS significantly reduced the abundance of the NO reducing functional gene, while the NO supply capacity (NO3[-]→NO) was improved, further favoring the anammox process. Batch tests and typical cycles further demonstrated that the anammox bacteria can stably acquire NO2[-], and anammox bacteria in the anoxic biofilm competed far more NO2[-] than denitrifying bacteria according to the typical pH curve. Accordingly, the abundance of Candidatus Brocadia, as detected by high throughput sequencing, decreased in the anoxic biofilms with the introduction of SS, but greatly increased (0.82%→2.22%) after SS discharge. This study sheds new light on the high in-situ enrichment of anammox in mainstream.}, } @article {pmid36458708, year = {2022}, author = {Güneş, B and Akçelik, N}, title = {[The Role of eDNA in Biofilm Structure of Enterococcus faecalis and Investigation of the Efficiency of Enzyme and Antibiotic Application in Biofilm Eradication].}, journal = {Mikrobiyoloji bulteni}, volume = {56}, number = {4}, pages = {606-619}, doi = {10.5578/mb.20229602}, pmid = {36458708}, issn = {0374-9096}, mesh = {Humans ; *Enterococcus faecalis/genetics ; *Anti-Bacterial Agents/pharmacology ; Biofilms ; Ampicillin/pharmacology ; Tetracycline ; DNA ; Deoxyribonuclease I/pharmacology ; }, abstract = {Biofilm structures, which are the predominant form of microbial life, are a formation that allows pathogenic microorganisms to remain alive by colonizing in different tissues and organs in the human body, as well as on inanimate surfaces. One of the important criteria in the fight against biofilm structures is the weakening of the exopolymeric matrix (EPS). Although it is known that extracellular DNA (eDNA) is one of the most abundant macromolecules in EPS in enterococcal biofilms, its function in biofilm structure is controversial. Since biofilm-forming enterococci are more resistant to antibiotics, the use of antibiotics together with agents that will damage the biofilm structure is being investigated. In this study, it was aimed to target eDNA with enzyme application for the eradication of Enterococcus faecalis biofilm structures and to investigate the increase of the effectiveness of antibiotic therapy on it. The amount of eDNA and optimal production time in biofilm structures of four different strains and isolates of E.faecalis (two clinical isolates coded 74 and 114, and two control strains coded ATCC 29212 and ATCC OG1RF) were determined by spectrophotometric measurement of PicoGreen fluorescence. For the eradication of biofilm; the effects of kanamycin, tetracycline, nalidixic acid, and ampicillin alone and in combination with Benzonase® and DNase I enzymes were investigated by viable cell count on Tryptic Soy Agar. It was determined that optimum biofilm production of E.faecalis strains and isolates occurred at 37°C for 12 hours. E.faecalis 114 isolate was identified as the strongest biofilm producer among the tested bacteria and the isolate containing the highest amount of eDNA (286 98 ng/µl) in the biofilm structure. While the tested antibiotics did not show significant antibiofilm activity against E.faecalis biofilm structures alone, strong antibiofilm activity was detected when ampicillin and tetracycline were applied together with DNase I enzyme. In this study, the use of DNA-degrading enzyme/antibiotic combinations in the eradication of enterococcal biofilms and the effectiveness of these combinations against eDNA were investigated for the first time in the literature. As a result, supportive results were obtained that the use of antibiotics together with the DNase I enzyme targeting the DNA molecule in the EPS structure will be more successful in the fight against the biofilm structures of E.faecalis, which is an important cause of nosocomial infection. These results need to be supported by further clinical studies.}, } @article {pmid36458226, year = {2022}, author = {Raj, K and Rishi, P and Shukla, G and Rudramurhty, SM and Mongad, DS and Kaur, A}, title = {Possible Contribution of Alternative Transcript Isoforms in Mature Biofilm Growth Phase of Candida glabrata.}, journal = {Indian journal of microbiology}, volume = {62}, number = {4}, pages = {583-601}, pmid = {36458226}, issn = {0046-8991}, abstract = {UNLABELLED: Expression of genome-wide alternative transcript isoforms and differential transcript isoform usage in different biological conditions (isoform switching) are responsible for the varied proteomic functional diversity in higher eukaryotic organisms. However, these mechanisms have not been studied in Candida glabrata, which is a potent eukaryotic opportunistic pathogen. Biofilm formation is an important virulence factor of C. glabrata that withstands antifungal drug stress and overcomes the host-immune response. Here, we present the genome-wide differential transcript isoform expression (DTE) and differential transcript isoform usage (DTU) in a mature biofilm growth phase of C. glabrata (clinical isolate; NCCPF 100,037) using the RNA sequencing approach. The DTE analysis generated 7837 transcript isoforms from the C. glabrata genome (5293 genes in total), and revealed that transcript isoforms generated from 292 genes showed significant DTU in the mature biofilm cells. Gene ontology, pathway analysis and protein-protein interactions of significant transcript isoforms, further substantiated that their specific expression and differential usage is required for transitioning the planktonic cells to biofilm in C. glabrata. The present study reported the possible role of expression of alternative transcript isoforms and differential transcript isoform usage in the mature biofilms of C. glabrata. The observation derived from the study may prove to be beneficial for making future antifungal therapeutic strategies.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12088-022-01036-7.}, } @article {pmid36457342, year = {2022}, author = {Fotso Techeu, UD and Kaktcham, PM and Momo, HK and Foko Kouam, EM and Tchamani Piame, L and Ngouenam, RJ and Zambou Ngoufack, F}, title = {Isolation, Characterization, and Effect on Biofilm Formation of Bacteriocin Produced by Lactococcus lactis F01 Isolated from Cyprinus carpio and Application for Biopreservation of Fish Sausage.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {8437926}, pmid = {36457342}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Bacteriocins/pharmacology ; Biofilms ; *Carps/microbiology ; Escherichia coli ; *Lactococcus lactis ; RNA, Ribosomal, 16S/genetics ; *Meat Products/microbiology ; *Food Preservation ; }, abstract = {The aim of this work was the screening of bacteriocin-producing LABs isolated from fish, the selection of promising/prominent strain(s), the characterization of the bacteriocin produced, and the evaluation of its potential to be used as biopreservative(s). Amplification and sequencing of the 16S rRNA gene of the bacteriocin-producing strain was performed. Then a partial purification of the produced bacteriocin, using a combination of ammonium sulfate and chloroform-methanol precipitation, was done. Its molecular weight was determined by SDS-PAGE. In addition, the action spectrum, the hemolysis test, and its ability to inhibit biofilm formation were analyzed. A total of 88 isolates of lactic acid bacteria (LAB) including one bacteriocin producer, which was identified as Lactococcus lactis F01, were collected. The bacteriocin was partially purified with an estimated yield of 40%. Regarding the SDS-PAGE profile, the secreted bacteriocin has molecular weight of about 3.5 kDa and was identified as class I bacteriocin. The antimicrobial test showed that the bacteriocin inhibits pathogenic and/or spoilage bacteria, 10 Gram-positive and 16 Gram-negative bacterial species. Moreover, it can inhibit biofilm formation from 1.3% (Escherichia coli) to 63.92% (Pseudomonas aeruginosa ATCC15692) depending on the strain. The hemolytic activity of novel bacteriocin was observed at the concentration of 10 μg/ml of bacteriocin crude extract, which was 0.7 ± 0.0029%. In addition, it exhibited good thermal and pH stability with retained antibacterial activity of 85.25% after treatment at 121°C for 20 min, as well as at a pH range between 2.0 and 10.0. Moreover, this bacteriocin showed the ability to inhibit the growth of bacterial culture load in fish sausage stored at 8°C for 28 days. Considering the results obtained, bacteriocin could be potentially exploited as an alternative to chemical preservatives or as a substitute for antibiotics.}, } @article {pmid36455808, year = {2023}, author = {Pirhaghi, M and Najarzadeh, Z and Moosavi-Movahedi, F and Shafizadeh, M and Mamashli, F and Atarod, D and Ghasemi, A and Morshedi, D and Meratan, AA and Otzen, DE and Saboury, AA}, title = {The anti-platelet drug ticlopidine inhibits FapC fibrillation and biofilm production: Highlighting its antibiotic activity.}, journal = {Biochimica et biophysica acta. Proteins and proteomics}, volume = {1871}, number = {2}, pages = {140883}, doi = {10.1016/j.bbapap.2022.140883}, pmid = {36455808}, issn = {1878-1454}, mesh = {Humans ; *Anti-Bacterial Agents/pharmacology/chemistry ; *Escherichia coli ; Gram-Negative Bacteria/physiology ; Gram-Positive Bacteria ; Biofilms ; }, abstract = {Multidrug resistance of bacteria and persistent infections related to biofilms, as well as the low availability of new antibacterial drugs, make it urgent to develop new antibiotics. Here, we evaluate the antibacterial and anti-biofilm properties of ticlopidine (TP), an anti-platelet aggregation drug, TP showed antibacterial activity against both gram-positive (MRSA) and gram-negative (E. coli, and P. aeruginosa) bacteria over a long treatment period. TP significantly reduced the survival of gram-negative bacteria in human blood though impact on gram-positives was more limited. TP may cause death in MRSA by inhibiting staphyloxanthin pigment synthesis, leading to oxidative stress, while scanning electron microscopy imaging indicate a loss of membrane integrity, damage, and consequent death due to lysis in gram-negative bacteria. TP showed good anti-biofilm activity against P. aeruginosa and MRSA, and a stronger biofilm degradation activity on P. aeruginosa compared to MRSA. Measuring fluorescence of the amyloid-reporter Thioflavin T (ThT) in biofilm implicated inhibition of amyloid formation as part of TP activity. This was confirmed by assays on the purified protein in P. aeruginosa, FapC, whose fibrillation kinetics was inhibited by TP. TP prolonged the lag phase of aggregation and reduced the subsequent growth rate and prolonging the lag phase to very long times provides ample opportunity to exert TP's antibacterial effect. We conclude that TP shows activity as an antibiotic against both gram-positive and gram-negative bacteria thanks to a broad range of activities, targeting bacterial metabolic processes, cellular structures and the biofilm matrix.}, } @article {pmid36453944, year = {2022}, author = {Mao, C and Wang, Y and Yang, Y and Li, L and Yuan, K and Cao, H and Qiu, Z and Guo, G and Wu, J and Peng, J}, title = {Cec4-Derived Peptide Inhibits Planktonic and Biofilm-Associated Methicillin Resistant Staphylococcus epidermidis.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0240922}, pmid = {36453944}, issn = {2165-0497}, mesh = {Humans ; Animals ; Mice ; *Staphylococcus epidermidis/physiology ; *Methicillin-Resistant Staphylococcus aureus ; Methicillin Resistance ; Plankton ; Biofilms ; Anti-Bacterial Agents/pharmacology/metabolism ; Peptides/pharmacology ; DNA/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Staphylococcus epidermidis is part of the normal microbiota that colonizes the skin and mucosal surfaces of human beings. Previous studies suggested that S. epidermidis possessed low virulence, but recent studies confirmed that it can acquire high virulence from Staphylococcus aureus and with the increasing detection of methicillin-resistant S. epidermidis. It has become a major pathogen of graft-associated and hospital-acquired infections. In previous studies, we modified the antimicrobial peptide Cec4 (41 amino acids) and obtained the derived peptide C9 (16 amino acids) showing better antimicrobial activity against S. epidermidis with an MIC value of 8 μg/mL. The peptide has rapid bactericidal activity without detectable high-level resistance, showing certain inhibition and eradication ability on S. epidermidis biofilms. The damage of cell membrane structures by C9 was observed by scanning emission microscopy (SEM) and transmission electron microscopy (TEM). In addition, C9 altered the S. epidermidis cell membrane permeability, depolarization levels, fluidity, and reactive oxygen species (ROS) accumulation and possessed the ability to bind genomic DNA. Analysis of the transcriptional profiles of C9-treated cells revealed changes in genes involved in cell wall and ribosome biosynthesis, membrane protein transport, oxidative stress, and DNA transcription regulation. At the same time, the median lethal dose of C9 in mice was more than 128 mg/kg, and the intraperitoneal administration of 64 mg/kg was less toxic to the liver and kidneys of mice. Furthermore, C9 also showed a certain therapeutic effect on the mouse bacteremia model. In conclusion, C9 may be a candidate drug against S. epidermidis, which has the potential to be further developed as an antibacterial therapeutic agent. IMPORTANCE S. epidermidis is one of the most important pathogens of graft-related infection and hospital-acquired infection. The growing problem of antibiotic resistance, as well as the emergence of bacterial pathogenicity, highlights the need for antimicrobials with new modes of action. Antimicrobial peptides have been extensively studied over the past 30 years as ideal alternatives to antibiotics, and we report here that the derived peptide C9 is characterized by rapid bactericidal and antibiofilm activity, avoiding the development of resistance by acting on multiple nonspecific targets of the cell membrane or cell components. In addition, it has therapeutic potential against S. epidermidis infection in vivo. This study provides a rationale for the further development and application of C9 as an effective candidate antibiotic.}, } @article {pmid36452923, year = {2022}, author = {Li, D and Liang, W and Hu, Q and Ren, J and Xue, F and Liu, Q and Tang, F}, title = {The effect of a spontaneous induction prophage, phi458, on biofilm formation and virulence in avian pathogenic Escherichia coli.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1049341}, pmid = {36452923}, issn = {1664-302X}, abstract = {Prophage sequences are present in most bacterial genomes and account for up to 20% of its host genome. Integration of temperate phages may have an impact on the expression of host genes, while some prophages could turn into the lytic cycle and affect bacterial host biological characteristics. We investigated the role of spontaneous induction prophages in avian pathogenic Escherichia coli (APEC), which is the causative agent of avian colibacillosis in poultry, and considered a potential zoonotic bacterium related to the fact it serves as an armory of extraintestinal pathogenic E. coli. We found that APEC strain DE458 had a high spontaneous induction rate in vivo and in vitro. The released phage particles, phi458, were isolated, purified, and sequenced, and the deletion mutant, DE458Δphi458, was constructed and characterized. Biofilm formation of DE458Δphi458 was strongly decreased compared to that of the wild-type strain (p < 0.01). In addition, while the addition of DNase (100 μg/ml) did not affect prophage release but could digest eDNA, it significantly reduced the biofilm production of DE458 biofilm to a level close to that of DE458Δphi458. Compared to DE458, the adhesion and invasion abilities of DE458Δphi458 increased by approximately 6-20 times (p < 0.05). The virulence of DE458Δphi458 was enhanced by approximately 10-fold in chickens based on a 50% lethal dose. Furthermore, avian infection assays showed that the bacterial loads of DE458Δphi458 in the lung and liver were increased by 16.5- and 10-fold (p < 0.05), respectively, compared with those of the WT strain. The qRT-PCR revealed that deletion of phi458 led to upregulation of type I fimbriate-related gene fimH and curli-related gene csgC by 3- and 2.8-fold, respectively (p < 0.01). Our study revealed that phi458 promoted biofilm formation by spontaneously inducing and decreasing virulence by repressing virulence genes.}, } @article {pmid36451302, year = {2023}, author = {Nyanasegran, PK and Nathan, S and Firdaus-Raih, M and Muhammad, NAN and Ng, CL}, title = {Biofilm Signaling, Composition and Regulation in Burkholderia pseudomallei.}, journal = {Journal of microbiology and biotechnology}, volume = {33}, number = {1}, pages = {15-27}, pmid = {36451302}, issn = {1738-8872}, mesh = {Humans ; *Burkholderia pseudomallei/genetics ; *Melioidosis/microbiology ; Biofilms ; *Anti-Infective Agents ; Bacterial Proteins/genetics/metabolism ; }, abstract = {The incidence of melioidosis cases caused by the gram-negative pathogen Burkholderia pseudomallei (BP) is seeing an increasing trend that has spread beyond its previously known endemic regions. Biofilms produced by BP have been associated with antimicrobial therapy limitation and relapse melioidosis, thus making it urgently necessary to understand the mechanisms of biofilm formation and their role in BP biology. Microbial cells aggregate and enclose within a self-produced matrix of extracellular polymeric substances (EPSs) to form biofilm. The transition mechanism of bacterial cells from planktonic state to initiate biofilm formation, which involves the formation of surface attachment microcolonies and the maturation of the biofilm matrix, is a dynamic and complex process. Despite the emerging findings on the biofilm formation process, systemic knowledge on the molecular mechanisms of biofilm formation in BP remains fractured. This review provides insights into the signaling systems, matrix composition, and the biosynthesis regulation of EPSs (exopolysaccharide, eDNA and proteins) that facilitate the formation of biofilms in order to present an overview of our current knowledge and the questions that remain regarding BP biofilms.}, } @article {pmid36450806, year = {2022}, author = {Aguirre, AM and Adegbite, AO and Sorg, JA}, title = {Clostridioides difficile bile salt hydrolase activity has substrate specificity and affects biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {94}, pmid = {36450806}, issn = {2055-5008}, support = {R01 AI116895/AI/NIAID NIH HHS/United States ; R21 AI144454/AI/NIAID NIH HHS/United States ; U01 AI124290/AI/NIAID NIH HHS/United States ; }, mesh = {*Clostridioides ; Substrate Specificity ; *Clostridioides difficile ; Bile Acids and Salts ; Cholic Acids ; Deoxycholic Acid ; Biofilms ; }, abstract = {The Clostridioides difficile pathogen is responsible for nosocomial infections. Germination is an essential step for the establishment of C. difficile infection (CDI) because toxins that are secreted by vegetative cells are responsible for the symptoms of CDI. Germination can be stimulated by the combinatorial actions of certain amino acids and either conjugated or deconjugated cholic acid-derived bile salts. During synthesis in the liver, cholic acid- and chenodeoxycholic acid-class bile salts are conjugated with either taurine or glycine at the C24 carboxyl. During GI transit, these conjugated bile salts are deconjugated by microbes that express bile salt hydrolases (BSHs). Here, we surprisingly find that several C. difficile strains have BSH activity. We observed this activity in both C. difficile vegetative cells and in spores and that the observed BSH activity was specific to taurine-derived bile salts. Additionally, we find that this BSH activity can produce cholate for metabolic conversion to deoxycholate by C. scindens. The C. scindens-produced deoxycholate signals to C. difficile to initiate biofilm formation. Our results show that C. difficile BSH activity has the potential to influence the interactions between microbes, and this could extend to the GI setting.}, } @article {pmid36450577, year = {2023}, author = {Maeda, T and Takayama, Y and Goto, M and Yoshida, H and Fujita, T and Tsuyuki, Y and Takahashi, T}, title = {Biofilm Production Ability of Streptococcus dysgalactiae Subsp. equisimilis: Associations with Host Species, Lancefield Group, Source, Clonal Complex, and Virulence-Associated Genes.}, journal = {Japanese journal of infectious diseases}, volume = {76}, number = {2}, pages = {135-144}, doi = {10.7883/yoken.JJID.2022.579}, pmid = {36450577}, issn = {1884-2836}, mesh = {Animals ; Humans ; *Streptococcal Infections/veterinary/microbiology ; Virulence/genetics ; Streptococcus ; Multilocus Sequence Typing ; }, abstract = {We assessed the biofilm production ability (BPA) of noninvasive Streptococcus dysgalactiae subsp. equisimilis (SDSE) in humans and companion animals and determined the relationship between bacterial populations with BPA and other host and microbiological features. Sixty-four isolates from companion animals and humans were collected along with host information. We measured BPA using crystal violet staining, in addition to emm typing, multilocus sequence typing, antimicrobial resistance (AMR) phenotyping/genotyping, and virulence-associated gene (VAG) detecting (prtF1-prtF2-lmb-cbp-sicG-srtp1-srtp2-brpA). Differences in the BPA of SDSE from different hosts and sources and different Lancefield groups were assessed. We analyzed the associations between populations with and without BPA (strong, moderate, weak, and no biofilm producers) and emm types, sequence types/clonal complexes (CCs), AMR phenotypes/genotypes, and VAG types. Seventeen, twenty-four, and twelve isolates were strong, moderate, and weak biofilm producers, respectively; eleven showed no BPA. There was a difference in the distribution of populations with BPA between human and animal origins and between isolates of groups G and C. We found an association between populations with BPA and the eye and ear source (vs. the pus and skin source). A relationship was observed between the populations with BPA and CC127 (vs. CC17). We observed no association between the populations with BPA and AMR phenotype/genotype. There was an association between the distribution of populations with BPA and srtp1 expression. Our observations suggest potential associations between populations with BPA and the host species, Lancefield group, source, CC, and VAG type.}, } @article {pmid36450176, year = {2023}, author = {Li, R and Liang, C and Svendsen, SB and Kisielius, V and Bester, K}, title = {Sartan blood pressure regulators in classical and biofilm wastewater treatment - Concentrations and metabolism.}, journal = {Water research}, volume = {229}, number = {}, pages = {119352}, doi = {10.1016/j.watres.2022.119352}, pmid = {36450176}, issn = {1879-2448}, mesh = {Humans ; Losartan/analysis ; Angiotensin II Type 1 Receptor Blockers/analysis/chemistry ; Irbesartan/analysis ; Wastewater ; Blood Pressure ; Sewage ; Valsartan/analysis ; Biofilms ; *Water Purification ; *Water Pollutants, Chemical/chemistry ; }, abstract = {Sartans are a group of pharmaceuticals widely used to regulate blood pressure. Their concentration levels were monitored in 80 wastewater treatment plants (WWTP) in the Baltic Sea Region, reached from limit of detection up to 6 µg/L. The concentrations were significantly different in different countries, but consistent within the respective country. The degradation of sartans (losartan, valsartan, irbesartan) in moving bed biofilm reactors (MBBRs) that utilize biofilms grown on mobile carriers to treat wastewater was investigated for the first time, and compared with the degradation in a conventional activated sludge (CAS) treatment plant. The results showed the formation of six microbial transformation products (TPs) of losartan, four of valsartan, and four of irbesartan in biological wastewater treatment. Four of these metabolites have not been described in the literature before. Chemical structures were suggested and selected TPs were verified and quantified depending on availability of true standards. Valsartan acid was a common TP of losartan, valsartan, and irbesartan. Losartan and irbesartan also shared one TP: losartan/irbesartan TP335. Based on the mass balance analysis, losartan carboxylic acid is the main TP of losartan, and valsartan acid is the main TP of valsartan during the biotransformation process. For irbesartan, TP447 is likely to be the main TP, as its peak areas were two orders of magnitude higher than those of all the other detected TPs of this compound. The effects of adapting biofilms to different biological oxygen demand (BOD) loading on the degradation of sartans as well as the formation of their TPs were investigated. Compared to feeding a poor substrate (pure effluent wastewater from a CAS), feeding with richer substrate (1/3 raw and 2/3 effluent wastewater) promoted the metabolism of most compounds (co-metabolization). However, the addition of raw wastewater inhibited some metabolic pathways of other compounds, such as from losartan/irbesartan to TP335 (competitive inhibition). The formation of irbesartan TP447 did not change with or without raw wastewater. Finally, the sartans and their TPs were investigated in a full-scale CAS wastewater treatment plant (WWTP). The removal of losartan, valsartan, and irbesartan ranged from 3.0 % to 72% and some of the transformation products (TPs) from human metabolism were also removed in the WWTP. However, some of the sartan TPs, i.e., valsartan acid, losartan carboxylic acid, irbesartan TP443 and losartan TP453, were formed in the WWTP. Relative high amounts of especially losartan carboxylic acid, which was detected with concentrations up to 2.27 µg/L were found in the effluent.}, } @article {pmid36449011, year = {2022}, author = {Torres-Mendieta, R and Nguyen, NHA and Guadagnini, A and Semerad, J and Łukowiec, D and Parma, P and Yang, J and Agnoli, S and Sevcu, A and Cajthaml, T and Cernik, M and Amendola, V}, title = {Growth suppression of bacteria by biofilm deterioration using silver nanoparticles with magnetic doping.}, journal = {Nanoscale}, volume = {14}, number = {48}, pages = {18143-18156}, doi = {10.1039/d2nr03902h}, pmid = {36449011}, issn = {2040-3372}, mesh = {Silver/pharmacology ; *Metal Nanoparticles ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Enterococcus faecalis ; *Anti-Infective Agents ; Magnetic Phenomena ; Microbial Sensitivity Tests ; }, abstract = {Decades of antibiotic use and misuse have generated selective pressure toward the rise of antibiotic-resistant bacteria, which now contaminate our environment and pose a major threat to humanity. According to the evolutionary "Red queen theory", developing new antimicrobial technologies is both urgent and mandatory. While new antibiotics and antibacterial technologies have been developed, most fail to penetrate the biofilm that protects bacteria against external antimicrobial attacks. Hence, new antimicrobial formulations should combine toxicity for bacteria, biofilm permeation ability, biofilm deterioration capability, and tolerability by the organism without renouncing compatibility with a sustainable, low-cost, and scalable production route as well as an acceptable ecological impact after the ineluctable release of the antibacterial compound in the environment. Here, we report on the use of silver nanoparticles (NPs) doped with magnetic elements (Co and Fe) that allow standard silver antibacterial agents to perforate bacterial biofilms through magnetophoretic migration upon the application of an external magnetic field. The method has been proved to be effective in opening micrometric channels and reducing the thicknesses of models of biofilms containing bacteria such as Enterococcus faecalis, Enterobacter cloacae, and Bacillus subtilis. Besides, the NPs increase the membrane lipid peroxidation biomarkers through the formation of reactive oxygen species in E. faecalis, E. cloacae, B. subtilis, and Pseudomonas putida colonies. The NPs are produced using a one-step, scalable, and environmentally low-cost procedure based on laser ablation in a liquid, allowing easy transfer to real-world applications. The antibacterial effectiveness of these magnetic silver NPs may be further optimized by engineering the external magnetic fields and surface conjugation with specific functionalities for biofilm disruption or bactericidal effectiveness.}, } @article {pmid36446019, year = {2023}, author = {Zou, P and Wang, Y and Cao, P and Li, P and Liu, J and Luan, Q}, title = {Weak direct current exerts synergistic effect with antibiotics and reduces the antibiotic resistance: An in vitro subgingival plaque biofilm model.}, journal = {Journal of periodontal research}, volume = {58}, number = {1}, pages = {143-154}, doi = {10.1111/jre.13076}, pmid = {36446019}, issn = {1600-0765}, mesh = {Humans ; *Anti-Bacterial Agents/pharmacology/therapeutic use ; Amoxicillin/pharmacology ; Metronidazole/pharmacology ; Amoxicillin-Potassium Clavulanate Combination/pharmacology ; *Dental Plaque/drug therapy/microbiology ; Biofilms ; Drug Resistance, Microbial ; }, abstract = {BACKGROUND AND OBJECTIVE: Weak direct current (DC) exerts killing effect and synergistic killing effect with antibiotics in some specific bacteria biofilms. However, the potential of weak DC alone or combined with periodontal antibiotics in controlling periodontal pathogens and plaque biofilms remains unclear. The objective of this study was to investigate whether weak DC could exert the anti-biofilm effect or enhance the killing effect of metronidazole (MTZ) and/or amoxicillin-clavulanate potassium (AMC) on subgingival plaque biofilms, by constructing an in vitro subgingival plaque biofilm model.

METHODS: The pooled subgingival plaque and saliva of patients with periodontitis (n = 10) were collected and cultured anaerobically on hydroxyapatite disks in vitro for 48 h to construct the subgingival plaque biofilm model. Then such models were stimulated with 0 μA DC alone (20 min/12 h), 1000 μA DC alone (20 min/12 h), 16 μg/ml MTZ, 16 μg/ml AMC or their combination, respectively. Through viable bacteria counting, metabolic activity assay, quantitative real-time PCR absolute quantification and 16S rDNA sequencing analysis, the anti-biofilm effect of 1000 μA DC and enhanced killing effects of 1000 μA DC combined with antibiotics (MTZ, AMC or MTZ+AMC) were explored.

RESULTS: The old subgingival plaque model (48 h) had no significant difference in total bacterial loads from subgingival plaque in situ, which achieved a similarity of 80%. The 1000 μA DC plus MTZ or AMC for 12 h showed a stronger synergistic killing effect than the same combination for 20 min. The metabolic activity was reduced to the lowest by DC plus MTZ+AMC, as 37.4% of that in the control group, while average synergistic killing effect reached 1.06 log units and average total bacterial loads decreased to 0.87 log units. Furthermore, the relative abundance of the genera Porphyromonas, Prevotella, Treponema_2, and Tannerella were decreased significantly.

CONCLUSION: The presence of weak DC (1000 μA) improved the killing effect of antibiotics on subgingival plaque biofilms, which might provide a novel strategy to reduce their antibiotic resistance.}, } @article {pmid36441750, year = {2022}, author = {Harley, BK and Quagraine, AM and Neglo, D and Aggrey, MO and Orman, E and Mireku-Gyimah, NA and Amengor, CD and Jato, J and Saaka, Y and Fleischer, TC}, title = {Metabolite profiling, antifungal, biofilm formation prevention and disruption of mature biofilm activities of Erythrina senegalensis stem bark extract against Candida albicans and Candida glabrata.}, journal = {PloS one}, volume = {17}, number = {11}, pages = {e0278096}, pmid = {36441750}, issn = {1932-6203}, mesh = {*Candida glabrata ; Candida albicans ; Antifungal Agents/pharmacology ; *Erythrina ; Fluconazole ; Nystatin/pharmacology ; Plant Bark ; Biofilms ; Candida ; Plant Extracts/pharmacology ; }, abstract = {The antifungal activity of the 70% ethanol stem bark extract of Erythrina senegalensis (ESB) against different strains and drug resistant clinical isolates of Candida albicans and Candida glabrata were evaluated in the study. The effect of ESB on biofilms as well as its activity in combination with fluconazole, nystatin or caspofungin against the Candida strains were also evaluated. We then evaluated the antifungal activity of a microemulsion formulation of ESB against planktonic and biofilms of the Candida species. UPLC-QTOF-MS2 analysis was then undertaken to identify the phytoconstituents of the extract and UPLC fingerprints developed for the routine authentication as part of quality control measures. ESB exerted strong antifungal activities against C. albicans ATCC 10231 and SC5314 strains, and C. glabrata ATCC 2001 strain with minimum inhibitory concentration (MIC) values from 3.91 to 31.25 μg/mL and minimum fungicidal concentrations (MFCs) that ranged from 62.5 to 250 μg/mL. It also exhibited potent antifungal activities (MIC = 4-64 μg/mL) against a collection of C. albicans and C. glabrata clinical isolates that were resistant to either nystatin or azole antifungals. The formulated ESB demonstrated higher antifungal potency against the C. albicans and C. glabrata strains with MIC values of 3.91-31.25 μg/mL which was the same as the MFC values. The extract and its microemulsion formulation were active against biofilms of the strains of the Candida species inhibiting their biofilm formations (SMIC50 = 16-64 μg/mL) and their preformed biofilms (SMIC50 = 128 ->512 μg/mL). ESB also exhibited synergistic antifungal action with fluconazole and nystatin against C. albicans ATCC 10231 and C. glabrata ATCC 2001 strains in the checkerboard assay. Chemical characterization of the extract revealed the presence of phenolic compounds such as flavonoids and their prenylated derivatives, anthracene glycosides and alkaloids. UPLC Fingerprints of the extract was also developed and validated for routine identification and authentication of the stem bark of E. senegalensis. The study findings have demonstrated that the stem bark of E. senegalensis is as a potential source of bioactive compounds that could be developed as novel antifungal agents.}, } @article {pmid36440643, year = {2022}, author = {Tkachuk, N and Zelena, L}, title = {Inhibition of heterotrophic bacterial biofilm in the soil ferrosphere by Streptomyces spp. and Bacillus velezensis.}, journal = {Biofouling}, volume = {38}, number = {9}, pages = {916-925}, doi = {10.1080/08927014.2022.2151362}, pmid = {36440643}, issn = {1029-2454}, mesh = {Biofilms ; Soil ; *Streptomyces ; *Disinfectants ; }, abstract = {The soil microbiome is involved in the processes of microbial corrosion, in particular, by the formation of biofilm. It has been proposed that an environmentally friendly solution to this corrosion might be through biological control. Bacillus velezensis NUChC C2b, Streptomyces gardneri ChNPU F3 and S. canus NUChC F2 were investigated as potentially 'green' biocides to prevent attachment to glass as a model surface and the formation of heterotrophic bacterial biofilm which participates in the corrosion process. Results showed high antagonistic and antibiofilm properties of S. gardneri ChNPU F3; which may be related to the formation of secondary antimicrobial metabolites by this strain. B. velezensis NUChC C2b and S. gardneri ChNPU F3 could be incorporated into green biocides - as components of antibiofilm agents that will protect material from bacterial corrosion or as agents that will prevent historical heritage damage.}, } @article {pmid36440493, year = {2023}, author = {Benson, R and Unnikrishnan, MK and Kurian, SJ and Velladath, SU and Rodrigues, GS and Chandrashekar Hariharapura, R and Muraleedharan, A and Bangalore Venkateshiah, D and Banerjee, B and Mukhopadhyay, C and Johnson, AS and Munisamy, M and Rao, M and Kochikuzhyil, BM and Sekhar Miraj, S}, title = {Vitamin D attenuates biofilm-associated infections via immunomodulation and cathelicidin expression: a narrative review.}, journal = {Expert review of anti-infective therapy}, volume = {21}, number = {1}, pages = {15-27}, doi = {10.1080/14787210.2023.2151439}, pmid = {36440493}, issn = {1744-8336}, mesh = {Humans ; *Vitamin D/pharmacology ; Cathelicidins ; Antimicrobial Cationic Peptides/pharmacology ; *Vitamin D Deficiency/complications/drug therapy ; Vitamins/pharmacology ; Antimicrobial Peptides ; Biofilms ; Cytokines ; }, abstract = {INTRODUCTION: Infections are becoming more difficult to treat, at least partly on account of microbes that produce biofilms. Reports suggest that decreased levels of antimicrobial peptides like cathelicidin, elevated levels of inflammatory cytokines, and biofilm formation are all associated with vitamin D deficiency, making vitamin D - deficient individuals more susceptible to infection. Infections attributable to biofilm-producing microbes can be managed by adjuvant therapy with vitamin D because of its immunomodulatory role, particularly because of the ability of vitamin D-pathway to induce the antimicrobial peptides like cathelicidin and decrease proinflammatory cytokines.

AREAS COVERED: This narrative review covers biofilm formation, infections associated with biofilm due to vitamin D deficiency, putative role of vitamin D in host protection and the effect of vitamin D supplementation in biofilm-associated infections. A comprehensive literature search in PubMed and Google Scholar utilizing suitable keywords at multiple time points extracted relevant articles.

EXPERT OPINION: Although vitamin D deficiency has been associated with infections by biofilm producing microbes, comprehensive clinical trials in various ethnicities are required to understand the likely relationships between vitamin D receptor gene expression, cathelicidin levels, and infection outcome. Current evidence hypothesizes that maintaining normal vitamin D level can help prevent and treat these infections.}, } @article {pmid36439211, year = {2022}, author = {Negrini, TC and Ren, Z and Miao, Y and Kim, D and Simon-Soro, Á and Liu, Y and Koo, H and Arthur, RA}, title = {Dietary sugars modulate bacterial-fungal interactions in saliva and inter-kingdom biofilm formation on apatitic surface.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {993640}, pmid = {36439211}, issn = {2235-2988}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; R90 DE031532/DE/NIDCR NIH HHS/United States ; }, mesh = {Child, Preschool ; Humans ; *Saliva/microbiology ; *Dietary Sugars ; Apatites ; Streptococcus mutans ; Biofilms ; Sucrose/pharmacology ; Starch/pharmacology ; Fructose ; Glucose ; }, abstract = {Bacteria and fungi can interact to form inter-kingdom biofilms in the oral cavity. Streptococcus mutans and Candida albicans are frequently detected in saliva and in dental biofilms associated with early childhood caries (tooth-decay), a prevalent oral disease induced by dietary sugars. However, how different sugars influence this bacterial-fungal interaction remains unclear. Here, we investigate whether specific sugars affect the inter-kingdom interaction in saliva and subsequent biofilm formation on tooth-mimetic surfaces. The microbes were incubated in saliva containing common dietary sugars (glucose and fructose, sucrose, starch, and combinations) and analyzed via fluorescence imaging and quantitative computational analyses. The bacterial and fungal cells in saliva were then transferred to hydroxyapatite discs (tooth mimic) to allow microbial binding and biofilm development. We found diverse bacterial-fungal aggregates which varied in size, structure, and spatial organization depending on the type of sugars. Sucrose and starch+sucrose induced the formation of large mixed-species aggregates characterized by bacterial clusters co-bound with fungal cells, whereas mostly single-cells were found in the absence of sugar or in the presence of glucose and fructose. Notably, both colonization and further growth on the apatitic surface were dependent on sugar-mediated aggregation, leading to biofilms with distinctive spatial organizations and 3D architectures. Starch+sucrose and sucrose-mediated aggregates developed into large and highly acidogenic biofilms with complex network of bacterial and fungal cells (yeast and hyphae) surrounded by an intricate matrix of extracellular glucans. In contrast, biofilms originated from glucose and fructose-mediated consortia (or without sugar) were sparsely distributed on the surface without structural integration, growing predominantly as individual species with reduced acidogenicity. These findings reveal the impact of dietary sugars on inter-kingdom interactions in saliva and how they mediate biofilm formation with distinctive structural organization and varying acidogenicity implicated with human tooth-decay.}, } @article {pmid36438838, year = {2022}, author = {Korycka-Machała, M and Kawka, M and Lach, J and Płocińska, R and Bekier, A and Dziadek, B and Brzostek, A and Płociński, P and Strapagiel, D and Szczesio, M and Gobis, K and Dziadek, J}, title = {2,4-Disubstituted pyridine derivatives are effective against intracellular and biofilm-forming tubercle bacilli.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {1004632}, pmid = {36438838}, issn = {1663-9812}, abstract = {It was recently reported that 4-substituted picolinohydrazonamides carrying hydrophilic cyclic amines, such as morpholine and pyrrolidine, at the end of their thiosemicarbazide chain have potent antimycobacterial activity in vitro at concentrations below 1 μg/ml. Here, two selected compounds, 2,4-disubstituted pyridine derivatives 11 and 15, revealed significant bactericidal activity against Mycobacterium tuberculosis localized intracellularly within human macrophages, as well as against biofilm-forming tubercle bacilli. Mutants were selected that were resistant to the investigated compounds at an efficiency similar to that identified in the presence of the first line antituberculosis drug rifampicin. The resistant mutants were viable in the presence of the tested compounds exclusively on solid media. Genome-wide sequencing of the mutants selected in the presence of compound 11 revealed the accumulation of nonsynonymous mutations in the mmpR5 gene encoding a transcriptional repressor of the MmpS5-MmpL5 efflux pump, whose upregulation has been associated with bedaquiline resistance. The depletion of MmpR5 in wild-type M. tuberculosis using CRISPR-Cas9 technology increased the resistance of this strain to compound 11. Mass spectrometry-based proteomics (LC-MS/MS) of wild-type tubercle bacilli growing in subinhibitory concentrations of compounds 11 or 15 revealed 15 overproduced proteins not detectable in the control cells, including virulence-related proteins.}, } @article {pmid36438092, year = {2022}, author = {Lee, J and Lee, J and Cho, Y and Choi, J and Han, SW}, title = {A putative 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase is involved in the virulence, carbohydrate metabolism, biofilm formation, twitching halo, and osmotic tolerance in Acidovorax citrulli.}, journal = {Frontiers in plant science}, volume = {13}, number = {}, pages = {1039420}, pmid = {36438092}, issn = {1664-462X}, abstract = {Acidovorax citrulli (Ac) is a gram-negative bacterium that causes bacterial fruit blotch (BFB) disease in cucurbit crops including watermelon. However, despite the great economic losses caused by this disease worldwide, Ac-resistant watermelon cultivars have not been developed. Therefore, characterizing the virulence factors/mechanisms of Ac would enable the development of effective control strategies against BFB disease. The 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase (BdpM) is known to participate in the glycolysis and gluconeogenesis pathways. However, the roles of the protein have not been characterized in Ac. To elucidate the functions of BdpmAc (Bdpm in Ac), comparative proteomic analysis and diverse phenotypic assays were conducted using a bdpmAc knockout mutant (bdpmAc:Tn) and a wild-type strain. The virulence of the mutant to watermelon was remarkably reduced in both germinated seed inoculation and leaf infiltration assays. Moreover, the mutant could not grow with fructose or pyruvate as a sole carbon source. However, the growth of the mutant was restored to levels similar to those of the wild-type strain in the presence of both fructose and pyruvate. Comparative proteomic analyses revealed that diverse proteins involved in motility and wall/membrane/envelop biogenesis were differentially abundant. Furthermore, the mutant exhibited decreased biofilm formation and twitching halo size. Interestingly, the mutant exhibited a higher tolerance against osmotic stress. Overall, our findings suggest that BdpmAc affects the virulence, glycolysis/gluconeogenesis, biofilm formation, twitching halo size, and osmotic tolerance of Ac, suggesting that this protein has pleiotropic properties. Collectively, our findings provide fundamental insights into the functions of a previously uncharacterized phosphoglycerate mutase in Ac.}, } @article {pmid36437878, year = {2022}, author = {Liu, S and Xu, A and Xie, B and Xin, F and Dong, W and Zhou, J and Jiang, M}, title = {Priority changes between biofilm exopolysaccharides synthesis and rhamnolipids production are mediated by a c-di-GMP-specific phosphodiesterase NbdA in Pseudomonas aeruginosa.}, journal = {iScience}, volume = {25}, number = {12}, pages = {105531}, pmid = {36437878}, issn = {2589-0042}, abstract = {The synthesis of biofilm exopolysaccharides and rhamnolipids (RLs) are two interrelated processes in Pseudomonas aeruginosa, but how bacteria coordinate these two processes remains unclear. We collected a P. aeruginosa KT1115 with rugose small colony variant (RSCV) phenotype from soil, and used it to study the dynamic regulation mechanism of biofilm polysaccharide and RLs synthesis. The results showed that the overproduction of biofilm exopolysaccharides at biofilm stage ultimately contributed the surge of RLs production at RLs stage. This phenomenon was further verified by comparing PAO1 with its engineered RSCV mutant, PAO1ΔwspF. Further genomic, transcriptomic analyses and gene deletion revealed that downregulation of c-di-GMP level was the key to switch biofilm exopolysaccharides accumulation to RLs surge, by transcriptionally upregulating a c-di-GMP phosphodiesterase NbdA. Overall, this study demonstrates the importance of c-di-GMP in coordinating biofilm exopolysaccharides and RLs synthesis, and provides an inspiration for enhancing RLs production through regulating c-di-GMP level.}, } @article {pmid36437333, year = {2022}, author = {Maslennikova, IL and Nekrasova, IV and Kuznetsova, MV}, title = {Interaction of Neutrophils and Biofilm Formed by Uropathogenic Escherichia coli Strains with Different Pathogenic Potential.}, journal = {Bulletin of experimental biology and medicine}, volume = {174}, number = {1}, pages = {51-56}, pmid = {36437333}, issn = {1573-8221}, mesh = {Humans ; *Uropathogenic Escherichia coli ; *Urinary Tract Infections ; }, abstract = {The biofilm formation by uropathogenic E. coli (UPEC) allows bacteria to avoid the influence of the host immune system that determines the pathogenesis of persistent urinary tract infections. The purpose of this work was to evaluate the mutual influence of neutrophils and biofilms formed by UPEC with different set of virulence-associated genes (VAGs). E. coli R11 and R32 strains with a wide range of virulence factors were characterized by low biofilm biomass that did not change after interaction with neutrophils. The biomass index decreased after interaction with neutrophils for strains with a limited set of pathogenicity factors (R33, R36, R45, and R44) and a "thick" biofilm. Bacterial cells and biofilm supernatants of all UPEC strains reduced viability (DiOC6(3)[+]/PI[-]) and stimulated early apoptosis (DiOC6(3)[-]/PI[-]) of neutrophils. The number of viable neutrophils was higher, while the number of apoptotic and necrotic (DiOC6(3)[-]/PI[+]) cells was lower under the action of supernatants of strains R44, R36, R45 in comparison with bacterial cells. Thus, modulation of the innate cell functions depends on the realization of the pathogenic potential of UPEC bacteria in urinary tract biofilms that determines the development of recurrent urinary tract infections.}, } @article {pmid36437322, year = {2022}, author = {Babushkina, IV and Mamonova, IA and Ulyanov, VY and Shpinyak, SP}, title = {Combined Effect of Ceftriaxon and Low-Frequency Ultrasound on the Viability of Staphylococcus epidermidis Cells in a Preformed Biofilm.}, journal = {Bulletin of experimental biology and medicine}, volume = {174}, number = {1}, pages = {47-50}, pmid = {36437322}, issn = {1573-8221}, mesh = {Humans ; *Staphylococcus epidermidis ; *Ceftriaxone/pharmacology ; }, abstract = {We studied the effect of low-frequency ultrasound on the antibacterial effect of ceftriaxone for Staphylococcus epidermidis strains isolated from biomaterial of patients with paraimplant inflammation after total replacement of large joints in the plankton and preformed biofilm forms. Low-frequency ultrasound had no antibacterial effect on the plankton S. epidermidis culture or bacterial cells in the biofilm, and combined exposure of the plankton culture to ultrasound and ceftriaxone did not modulate the antibacterial activity of ceftriaxone. The exposure of the biofilm formed by S. epidermidis strains to low-frequency ultrasound increased the sensitivity of bacterial cells to ceftriaxone in a concentration range of 5-200 μg/ml.}, } @article {pmid36437129, year = {2022}, author = {Nedeljkovic, I and Doulabi, BZ and Abdelaziz, M and Feilzer, AJ and Exterkate, RAM and Szafert, S and Gulia, N and Krejci, I and Kleverlaan, CJ}, title = {Cytotoxicity and anti-biofilm properties of novel hybrid-glass-based caries infiltrant.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {38}, number = {12}, pages = {2052-2061}, doi = {10.1016/j.dental.2022.11.018}, pmid = {36437129}, issn = {1879-0097}, mesh = {Animals ; Mice ; *Dental Caries Susceptibility ; *Dental Caries ; Biofilms ; Glass ; Lactic Acid ; }, abstract = {OBJECTIVES: To assess the cytotoxicity of an experimental hybrid-glass-based infiltrant and its effect on biofilm attachment, growth and metabolic activity, and to compare it to the resin-based infiltrant Icon.

METHODS: Cytotoxicity of hybrid-glass-based material (EXP) and resin-based infiltrant Icon (Icon) was tested in direct contact tests on freshly cured (direct_mat) and on materials kept for 24 h in cell culture medium (direct_exmat), and extract test with materials 24-h extracts (extract). Cell viability of L929 mouse fibroblast cell line was measured with MTT assay, according to ISO10993-5:2009. Biofilm attachment (5 h), growth (24 h and 48 h) and lactic-acid production (24 h and 48 h) on glass-disk specimens coated with EXP or Icon, or uncoated (control), were assessed using a microcosm biofilm model and Amsterdam Active Attachment system. At indicated time points, biofilms were harvested, plated, and CFU counts were determined, while lactic-acid production was measured colorimetrically.

RESULTS: Cell viability reduction by EXP was below 30%-threshold in direct contact tests, while in extract test an increased cell viability was observed. Icon reduced cell viability substantially in all three tests. Significantly less bacteria attached to the surface of EXP after 5 h compared to Icon and control. Biofilm growth was significantly lower on EXP than on Icon and control after 24 h, but this difference was smaller and statistically insignificant after 48 h. There was no difference in lactic-acid production among groups.

SIGNIFICANCE: Novel hybrid-glass-based infiltrant seems to have a better biocompatibility and accumulates on its surface less bacteria than resin-based infiltrant, which makes it an attractive resin-free alternative.}, } @article {pmid36436859, year = {2023}, author = {Bellich, B and Terán, LC and Fazli, MM and Berti, F and Rizzo, R and Tolker-Nielsen, T and Cescutti, P}, title = {The Bep gene cluster in Burkholderia cenocepacia H111 codes for a water-insoluble exopolysaccharide essential for biofilm formation.}, journal = {Carbohydrate polymers}, volume = {301}, number = {Pt A}, pages = {120318}, pmid = {36436859}, issn = {1879-1344}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Burkholderia cenocepacia/genetics ; Water ; Multigene Family ; Biofilms ; Polysaccharides ; Anti-Bacterial Agents ; }, abstract = {Burkholderia cenocepacia is an opportunistic pathogen isolated from cystic fibrosis patients where it causes infections that are extremely difficult to treat with antibiotics, and sometimes have a fatal outcome. Biofilm is a virulence trait of B. cenocepacia, and is associated with infection persistence and increased tolerance to antibiotics. In biofilms exopolysaccharides have an important role, conferring mechanical stability and antibiotic tolerance. Two different exopolysaccharides were isolated from B. cenocepacia H111 biofilms: a water-soluble polysaccharide rich in rhamnose and containing an L-Man residue, and a water-insoluble polymer made of glucose, galactose and mannose. In the present work, the product encoded by B. cenocepacia H111 bepA-L gene cluster was identified as the water-insoluble exopolysaccharide, using mutant strains and NMR spectroscopy of the purified polysaccharides. It was also demonstrated that the B. cenocepacia H111 wild type strain produces the water-insoluble exopolysaccharide in pellicles, thus underlining its potential importance in in vivo infections.}, } @article {pmid36436412, year = {2023}, author = {Woo, J and Guk, JH and Yi, S and Lee, J and Song, H and Kim, WH and Cho, S}, title = {Effect of biofilm formation by antimicrobial-resistant gram-negative bacteria in cold storage on survival in dairy processing lines.}, journal = {International journal of food microbiology}, volume = {386}, number = {}, pages = {110019}, doi = {10.1016/j.ijfoodmicro.2022.110019}, pmid = {36436412}, issn = {1879-3460}, mesh = {Humans ; *Bacteria ; Dairy Products/microbiology ; Gram-Negative Bacteria/genetics ; *Anti-Infective Agents ; Biofilms ; }, abstract = {Antimicrobial-resistant gram-negative bacteria in dairy products can transfer antimicrobial resistance to gut microbiota in humans and can adversely impact the product quality. In this study, we aimed to investigate their distribution in dairy processing lines and evaluate biofilm formation and heat tolerance under dairy processing line-like conditions. Additionally, we compared the relative expression of general and heat stress-related genes as well as spoilage-related gene between biofilm and planktonic cells under consecutive stresses, similar to those in dairy processing lines. Most species of gram-negative bacteria isolated from five different dairy processing plants were resistant to one or more antimicrobials. Biofilm formation by the bacteria at 5 °C increased with the increase in exposure time. Moreover, cells in biofilms remained viable under heat treatment, whereas all planktonic cells of the selected strains died. The expression of heat-shock-related genes significantly increased with heat treatment in the biofilms but mostly decreased in the planktonic cells. Thus, biofilm formation under raw milk storage conditions may improve the tolerance of antimicrobial-resistant gram-negative bacteria to pasteurization, thereby increasing their persistence in dairy processing lines and products. Furthermore, the difference in response to heat stress between biofilm and planktonic cells may be attributed to the differential expression of heat stress-related genes. Therefore, this study contributes to the understanding of how gram-negative bacteria persist under consecutive stresses in dairy processing procedures and the potential mechanism underlying heat tolerance in biofilms.}, } @article {pmid36435319, year = {2023}, author = {Pořízka, P and Brunnbauer, L and Porkert, M and Rozman, U and Marolt, G and Holub, D and Kizovský, M and Benešová, M and Samek, O and Limbeck, A and Kaiser, J and Kalčíková, G}, title = {Laser-based techniques: Novel tools for the identification and characterization of aged microplastics with developed biofilm.}, journal = {Chemosphere}, volume = {313}, number = {}, pages = {137373}, doi = {10.1016/j.chemosphere.2022.137373}, pmid = {36435319}, issn = {1879-1298}, mesh = {*Microplastics ; Plastics/analysis ; Polypropylenes/analysis ; Metals/analysis ; Lasers ; Biofilms ; *Water Pollutants, Chemical/analysis ; Environmental Monitoring ; }, abstract = {Microplastics found in the environment are often covered with a biofilm, which makes their analysis difficult. Therefore, the biofilm is usually removed before analysis, which may affect the microplastic particles or lead to their loss during the procedure. In this work, we used laser-based analytical techniques and evaluated their performance in detecting, characterizing, and classifying pristine and aged microplastics with a developed biofilm. Five types of microplastics from different polymers were selected (polyamide, polyethylene, polyethylene terephthalate, polypropylene, and polyvinyl chloride) and aged under controlled conditions in freshwater and wastewater. The development of biofilm and the changes in the properties of the microplastic were evaluated. The pristine and aged microplastics were characterized by standard methods (e.g., optical and scanning electron microscopy, and Raman spectroscopy), and then laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were used. The results show that LIBS could identify different types of plastics regardless of the ageing and major biotic elements of the biofilm layer. LA-ICP-MS showed a high sensitivity to metals, which can be used as markers for various plastics. In addition, LA-ICP-MS can be employed in studies to monitor the adsorption and desorption (leaching) of metals during the ageing of microplastics. The use of these laser-based analytical techniques was found to be beneficial in the study of environmentally relevant microplastics.}, } @article {pmid36434697, year = {2022}, author = {Wen, J and Wang, Z and Du, X and Liu, R and Wang, J}, title = {Antibioflm effects of extracellular matrix degradative agents on the biofilm of different strains of multi-drug resistant Corynebacterium striatum.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {21}, number = {1}, pages = {53}, pmid = {36434697}, issn = {1476-0711}, support = {NYFY ZD 012//Major project of Affiliated hospital of Inner Mongolia Medical University/ ; 82260416//National Natural Science Foundation of China/ ; 2022YFSH0072//Science and Technology Plan Project of Inner Mongolian Autonomous Region/ ; }, mesh = {RNA, Ribosomal, 16S/genetics ; Endopeptidase K/pharmacology ; *Anti-Bacterial Agents/pharmacology ; *Biofilms ; Deoxyribonuclease I/pharmacology ; Extracellular Matrix ; }, abstract = {BACKGROUND: Corynebacterium striatum is a microorganism with an excellent capacity for biofilm production and thus has been correlated with nosocomial transmission and invasive infections. However, little is known about the mechanism of biofilm formation of this commensal pathogen. In this study, we aimed to investigate the biofilm formation abilities of multidrug-resistant Corynebacterium striatum clinical isolates and the roles of extracellular proteins, exopolysaccharides and extracellular DNA in mediating more robust biofilm formation by the isolates of C. striatum.

METHODS: C. striatum isolates were identified using VITEK-2 ANC card, matrix-assisted laser desorption/ionization-time of flight mass spectrometry and 16S rRNA sequencing. The antibiotic susceptibility test was performed using the broth microdilution method. The distribution of spaDEF genes among C. striatum isolates was detected by polymerase chain reaction, and pulsed-field gel electrophoresis typing was employed to analyze the genotypes of the isolates. Crystal violet staining and scanning electron microscopy techniques were used to detect biofilm production by C. striatum isolates. Biofilm degradation assay was performed to observe the effects of extracellular matrix degradative agents (proteinase K, dispersin B, and DNase I) on C. striatum biofilms.

RESULTS: Twenty-seven C. striatum isolates were enrolled in the study, and the resistance rates were the highest (100%, 27/27) against penicillin and ceftriaxone. Approximately 96.3% (26/27) C. striatum isolates were resistant to at least three different types of antimicrobial agents tested. All isolates were confirmed to be biofilm producers, and 74.07% (20/27) isolates presented moderate to strong biofilm production abilities. P7 genotype (44.4%, 12/27) was identified to as the predominant genotype, and all of isolates belonging to this genotype were multidrug-resistant and had stronger biofilm-forming abilities. Most C. striatum isolates (74.07%, 20/27) carry spaD, spaE, and spaF genes, which encode spa-type pili. However, the correlation between the expression of spa-type genes and the biofilm production abilities of the C. striatum isolates was not found. The biofilms of 80% (8/10), 90% (9/10), and 100% (10/10) C. striatum isolates with moderate to strong biofilm production abilities were significantly eliminated upon the treatment of dispersin B (20 μg/mL), DNase I (20 μg/mL), and proteinase K (20 μg/mL) (p < 0.05), respectively. For the combination groups with two kinds of biofilm-degradative agents, the combination of 20 μg/mL proteinase K/dispersin B showed the strongest biofilm-eliminating effects, when the biofilms of 90% (9/10) C. striatum isolates degraded more than 50%.

CONCLUSIONS: The C. striatum isolates that belonged to the predominant genotype showed a multidrug resistance (MDR) phenotype and strong biofilm formation abilities. Extracellular matrix seems to be an essential determinant in mediating biofilm formation of MDR C. striatum, since extracellular matrix degradative agents (proteinase K, dispersin B and DNase I) showed strong biofilm-eliminating effects toward multidrug-resistant C. striatum isolates. The findings of this study highlight new ideas/directions to explore the whole nature of biofilm formation of C. striatum and the function of extracellular matrix in this process.}, } @article {pmid36433140, year = {2022}, author = {Murtuza, SA and Matin, K and Hiraishi, N and Shimada, Y}, title = {Optimal Surface Pre-Reacted Glass Filler Ratio in a Dental Varnish Effective for Inhibition of Biofilm-Induced Root Dentin Demineralization.}, journal = {Polymers}, volume = {14}, number = {22}, pages = {}, pmid = {36433140}, issn = {2073-4360}, abstract = {A unique type of dental varnish (DV) containing surface pre-reacted glass (S-PRG) fillers of different concentrations was evaluated to determine the unpresented optimal ratio for inhibiting root dentin bio-demineralization. S-PRG DVs (10% to 40%)—10%-S, 20%-S, 30%-S, and 40%-S—were applied to bovine root dentin blocks and compared with controls—0%-f (no S-PRG) and 5%-NaF (5%-NaF). The Streptococcus mutans biofilm challenge was executed inside and outside an oral biofilm reactor for 7 days. The specimens were examined using a confocal laser scanning microscope and swept-source optical coherence tomography. Furthermore, they were observed using a scanning electron microscope and analyzed using energy-dispersive X-ray spectroscopy. The roughness (SzJIS) due to leaching of DV materials and demineralization depth were significantly less in the S-PRG groups than the control groups (p < 0.05). Complete or partially plugged dentinal tubules (DTs) were observed in 20%-S, 30%-S, and 40%-S, while wide-open DTs were observed more in controls. Cylindrical tags were present in groups containing more than 20% S-PRG. F, Na, Al, and Sr were detected in a higher percentile ratio in the 20%-S, 30%-S, and 40%-S groups compared to 0%-f and 10%-S. Nonetheless, it is suggested that incorporating 20% to 30% S-PRG fillers in DVs would be effective enough as an anti-demineralization coating, together with supplementing minerals; further evaluation is required to validate these findings.}, } @article {pmid36432584, year = {2022}, author = {Lieske, B and Makarova, N and Jagemann, B and Walther, C and Ebinghaus, M and Zyriax, BC and Aarabi, G}, title = {Inflammatory Response in Oral Biofilm during Pregnancy: A Systematic Review.}, journal = {Nutrients}, volume = {14}, number = {22}, pages = {}, pmid = {36432584}, issn = {2072-6643}, mesh = {Pregnancy ; Humans ; Female ; *Pregnancy Complications ; Biomarkers ; Biofilms ; }, abstract = {Understanding the inflammatory response in oral biofilm during pregnancy and its association with oral and maternal health is essential for identifying biomarker patterns that may serve as markers of pregnancy-related complications. We aimed to conduct a systematic review of the available literature to assess: (1) inflammatory responses in oral biofilm during pregnancy, (2) the association between inflammatory responses in oral biofilm during pregnancy and maternal, oral or systemic conditions, (3) changes in the response of inflammatory biomarkers found in the oral biofilm during different pregnancy stages, and (4) the value of other risk factors such as nutrition and lifestyle. PubMed, Web of Science and Cochrane Library were systematically searched from inception until April 2022. From 5441 records, 39 studies were included for qualitative assessment. The oral biofilm in pregnant women was associated with increased inflammatory biomarkers when compared to non-pregnant women. Levels of inflammatory biomarkers in the oral biofilm were found to be highest in pregnant women with systemic conditions. Increased inflammatory biomarkers in the oral biofilm were also associated with worse oral health outcomes. Given the importance of nutrition and lifestyle for pregnancy and oral health outcomes and the fact that these factors were largely excluded in the included studies, future research should consider a holistic view of the mother during pregnancy to capture physiological, hormonal, immunologic, and metabolic changes in the context of inflammatory responses.}, } @article {pmid36432345, year = {2022}, author = {Lethongkam, S and Paosen, S and Bilhman, S and Dumjun, K and Wunnoo, S and Choojit, S and Siri, R and Daengngam, C and Voravuthikunchai, SP and Bejrananda, T}, title = {Eucalyptus-Mediated Synthesized Silver Nanoparticles-Coated Urinary Catheter Inhibits Microbial Migration and Biofilm Formation.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {22}, pages = {}, pmid = {36432345}, issn = {2079-4991}, abstract = {Catheter-associated urinary tract infections (CAUTIs) are significant complications among catheterized patients, resulting in increased morbidity, mortality rates, and healthcare costs. Foley urinary catheters coated with synthesized silver nanoparticles (AgNPs) using Eucalyptus camaldulensis leaf extract were developed using a green chemistry principle. In situ-deposited AgNPs with particle size ranging between 20 and 120 nm on the catheter surface were illustrated by scanning electron microscopy. Atomic force microscopy revealed the changes in surface roughness after coating with nanoparticles. The coated catheter could significantly inhibit microbial adhesion and biofilm formation performed in pooled human urine-supplemented media to mimic a microenvironment during infections (p 0.05). AgNPs-coated catheter exhibited broad-spectrum antimicrobial activity against important pathogens, causing CAUTIs with no cytotoxic effects on HeLa cells. A reduction in microbial viability in biofilms was observed under confocal laser scanning microscopy. A catheter bridge model demonstrated complete prevention of Proteus mirabilis migration by the coated catheter. Significant inhibition of ascending motility of Escherichia coli and P. mirabilis along the AgNPs-coated catheter was demonstrated in an in vitro bladder model (p 0.05). The results suggested that the AgNPs-coated urinary catheter could be applied as an alternative strategy to minimize the risk of CAUTIs by preventing bacterial colonization and biofilm formation.}, } @article {pmid36431942, year = {2022}, author = {Abdel Bar, FM and Alossaimi, MA and Elekhnawy, E and Alzeer, MAA and Abo Kamer, A and Moglad, E and ElNaggar, MH}, title = {Anti-Quorum Sensing and Anti-Biofilm Activity of Pelargonium × hortorum Root Extract against Pseudomonas aeruginosa: Combinatorial Effect of Catechin and Gallic Acid.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {22}, pages = {}, pmid = {36431942}, issn = {1420-3049}, mesh = {Mice ; Animals ; Pseudomonas aeruginosa ; *Pelargonium ; *Catechin/pharmacology/metabolism ; Gallic Acid/pharmacology/metabolism ; Plant Extracts/pharmacology/metabolism ; }, abstract = {HPLC-UV was used to compare the major constituents of two Pelargonium × hortorum cultivars and Pelargonium sidoides root extract. It revealed the presence of catechin and gallic acid in high concentrations and the absence of umckalin in P. × hortorum root extracts. The antibacterial activity of these extracts was screened against 19 Pseudomonas aeruginosa clinical isolates. P. × hortorum root extracts showed the lowest MIC values (512-1024 µg/mL). This activity was concluded to be attributable to the high concentrations of catechin and gallic acid. The anti-biofilm activity of catechin, gallic acid, and their combination was examined by a crystal violet assay. The combination reduced the percentage of strong and moderate biofilm-forming isolates from 52.63% to 5.26%. The impact on lasI and lasR genes expression using qRT-PCR and simultaneous docking against LasR protein was explored. The combination downregulated lasI and lasR gene expression in eight and six P. aeruginosa isolates, respectively, and showed the greatest docking score. Additionally, the in vivo protection capability of this combination in infected mice showed enhancement in the survival rate. Our study revealed the potential biofilm and quorum-sensing-inhibitory activity of the catechin and gallic acid combination as a novel alternative to inhibit bacterial pathogenicity.}, } @article {pmid36430935, year = {2022}, author = {Czechowicz, P and Nowicka, J and Neubauer, D and Chodaczek, G and Krzyżek, P and Gościniak, G}, title = {Activity of Novel Ultrashort Cyclic Lipopeptides against Biofilm of Candida albicans Isolated from VVC in the Ex Vivo Animal Vaginal Model and BioFlux Biofilm Model-A Pilot Study.}, journal = {International journal of molecular sciences}, volume = {23}, number = {22}, pages = {}, pmid = {36430935}, issn = {1422-0067}, support = {STM.A130.20.102//Ministry of Health/ ; SUBZ.A130.22.010//Ministry of Health/ ; 2014/14/E/NZ6/00365//National Science Center/ ; IA/SP/453975/2020//National Centre for Research and Development/ ; }, mesh = {Mice ; Humans ; Female ; Animals ; *Candidiasis, Vulvovaginal/drug therapy/microbiology ; Candida albicans ; Pilot Projects ; Fluconazole/pharmacology ; Biofilms ; Candida ; Vagina/microbiology ; Disease Models, Animal ; Anti-Bacterial Agents/pharmacology ; Lipopeptides/pharmacology/therapeutic use ; }, abstract = {In recent years, clinicians and doctors have become increasingly interested in fungal infections, including those affecting the mucous membranes. Vulvovaginal candidiasis (VVC) is no exception. The etiology of this infection remains unexplained to this day, as well as the role and significance of asymptomatic vaginal Candida colonization. There are also indications that in the case of VVC, standard methods of determining drug susceptibility to antifungal drugs may not have a real impact on their clinical effectiveness-which would explain, among other things, treatment failures and relapse rates. The aim of the study was to verify the promising results obtained previously in vitro using standard methods, in a newly developed ex vivo model, using tissue fragments of the mouse vagina. The main goal of the study was to determine whether the selected ultrashort cyclic lipopeptides (USCLs) and their combinations with fluconazole at specific concentrations are equally effective against Candida forming a biofilm directly on the surface of the vaginal epithelium. In addition, the verification was also performed with the use of another model for the study of microorganisms (biofilms) in vitro-the BioFlux system, under microfluidic conditions. The obtained results indicate the ineffectiveness of the tested substances ex vivo at concentrations eradicating biofilm in vitro. Nevertheless, the relatively most favorable and promising results were still obtained in the case of combination therapy-a combination of low concentrations of lipopeptides (mainly linear analogs) with mycostatic fluconazole. Additionally, using BioFlux, it was not possible to confirm the previously obtained results. However, an inhibiting effect of the tested lipopeptides on the development of biofilm under microfluidic conditions was demonstrated. There is an incompatibility between the classic in vitro methods, the newer BioFlux method of biofilm testing, offering many advantages postulated elsewhere, and the ex vivo method. This incompatibility is another argument for the need, on the one hand, to intensify research on the pathomechanism of VVC, and, on the other hand, to verify and maybe modify the standard methods used in the determination of Candida susceptibility.}, } @article {pmid36430929, year = {2022}, author = {Zhang, L and Cai, Y and Li, L and Chen, C and Zhao, H and Zhang, Z and Liu, Y and Wang, Y and Tian, C and Liu, M}, title = {Effects of Luteolin on Biofilm of Trueperella pyogenes and Its Therapeutic Effect on Rat Endometritis.}, journal = {International journal of molecular sciences}, volume = {23}, number = {22}, pages = {}, pmid = {36430929}, issn = {1422-0067}, support = {31972736//National Natural Science Foundation of China/ ; 32002344//National Natural Science Foundation of China/ ; }, mesh = {Female ; Humans ; Rats ; Animals ; *Luteolin/pharmacology/therapeutic use ; *Endometritis/drug therapy ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Flavonoids/pharmacology/therapeutic use ; }, abstract = {Trueperella pyogenes is an opportunistic pathogen that causes suppurative infections in animals. The development of new anti-biofilm drugs will improve the current treatment status for controlling T. pyogenes infections in the animal husbandry industry. Luteolin is a naturally derived flavonoid compound with antibacterial properties. In this study, the effects and the mechanism of luteolin on T. pyogenes biofilm were analyzed and explored. The MBIC and MBEC of luteolin on T. pyogenes were 156 μg/mL and 312 μg/mL, respectively. The anti-biofilm effects of luteolin were also observed by a confocal laser microscope and scanning electron microscope. The results indicated that 312 μg/mL of luteolin could disperse large pieces of biofilm into small clusters after 8 h of treatment. According to the real-time quantitative PCR detection results, luteolin could significantly inhibit the relative expression of the biofilm-associated genes luxS, plo, rbsB and lsrB. In addition, the in vivo anti-biofilm activity of luteolin against T. pyogenes was studied using a rat endometritis model established by glacial acetic acid stimulation and T. pyogenes intrauterine infusion. Our study showed that luteolin could significantly reduce the symptoms of rat endometritis. These data may provide new opinions on the clinical treatment of luteolin and other flavonoid compounds on T. pyogenes biofilm-associated infections.}, } @article {pmid36430871, year = {2022}, author = {Lamret, F and Varin-Simon, J and Six, M and Thoraval, L and Chevrier, J and Adam, C and Guillaume, C and Velard, F and Gangloff, SC and Reffuveille, F}, title = {Human Osteoblast-Conditioned Media Can Influence Staphylococcus aureus Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {23}, number = {22}, pages = {}, pmid = {36430871}, issn = {1422-0067}, support = {COSIBIOOS//Region Grand--Est/ ; COSIBIOOS//Fondation URCA/ ; }, mesh = {Humans ; Staphylococcus aureus ; *Methicillin-Resistant Staphylococcus aureus ; Culture Media, Conditioned/pharmacology ; Tumor Necrosis Factor-alpha/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Staphylococcal Infections/microbiology ; Biofilms ; Osteoblasts ; }, abstract = {Osteoblasts are bone-forming and highly active cells participating in bone homeostasis. In the case of osteomyelitis and more specifically prosthetic joint infections (PJI) for which Staphylococcus aureus (S. aureus) is mainly involved, the interaction between osteoblasts and S. aureus results in impaired bone homeostasis. If, so far, most of the studies of osteoblasts and S. aureus interactions were focused on osteoblast response following direct interactions with co-culture and/or internalization models, less is known about the effect of osteoblast factors on S. aureus biofilm formation. In the present study, we investigated the effect of human osteoblast culture supernatant on methicillin sensitive S. aureus (MSSA) SH1000 and methicillin resistant S. aureus (MRSA) USA300. Firstly, Saos-2 cell line was incubated with either medium containing TNF-α to mimic the inflammatory periprosthetic environment or with regular medium. Biofilm biomass was slightly increased for both strains in the presence of culture supernatant collected from Saos-2 cells, stimulated or not with TNF-α. In such conditions, SH1000 was able to develop microcolonies, suggesting a rearrangement in biofilm organization. However, the biofilm matrix and regulation of genes dedicated to biofilm formation were not substantially changed. Secondly, culture supernatant obtained from primary osteoblast culture induced varied response from SH1000 strain depending on the different donors tested, whereas USA300 was only slightly affected. This suggested that the sensitivity to bone cell secretions is strain dependent. Our results have shown the impact of osteoblast secretions on bacteria and further identification of involved factors will help to manage PJI.}, } @article {pmid36430545, year = {2022}, author = {Cattò, C and Corte, L and Roscini, L and Cardinali, G and Villa, F and Cappitelli, F}, title = {Metabolomic and Proteomic Changes in Candida albicans Biofilm in Response to Zosteric Acid Treatment.}, journal = {International journal of molecular sciences}, volume = {23}, number = {22}, pages = {}, pmid = {36430545}, issn = {1422-0067}, support = {//Italian Society for Agricultural Food and Environmental Microbiology/ ; }, mesh = {*Candida albicans ; *Proteomics ; Biofilms ; Sulfuric Acid Esters/pharmacology ; }, abstract = {Zosteric acid (ZA) is a secondary metabolite of the seagrass Zostera marina, with antibiofilm activity against fungi. Information concerning its mechanisms of action is lacking and this limits the development of more potent derivatives based on the same target and activity structure. The aim of this work was to investigate the ZA mode of action by analyzing the metabolic status of Candida albicans biofilm and its protein expression profile upon ZA treatment. Fourier-Transform Infrared Spectroscopy confirmed that ZA modified the metabolomic response of treated cells, showing changes in the spectral regions, mainly related to the protein compartment. Nano Liquid Chromatography-High-Resolution Mass Spectrometry highlighted that 10 proteins were differentially expressed in the C. albicans proteome upon ZA treatment. Proteins involved in the biogenesis, structure and integrity of cell walls as well as adhesion and stable attachment of hyphae were found downregulated, whereas some proteins involved in the stress response were found overexpressed. Additionally, ZA was involved in the modulation of non-DNA-based epigenetic regulatory mechanisms triggered by reactive oxygen species. These results partially clarified the ZA mechanism of action against fungi and provided insight into the major C. albicans pathways responsible for biofilm formation.}, } @article {pmid36427613, year = {2023}, author = {Liu, T and Feng, Z and Li, Z and Lin, Z and Chen, L and Li, B and Chen, Z and Wu, Z and Zeng, J and Zhang, J and Hong, J and Xia, H and Li, L and Ye, X and Zhang, Y}, title = {Carboxymethyl chitosan/sodium alginate hydrogels with polydopamine coatings as promising dressings for eliminating biofilm and multidrug-resistant bacteria induced wound healing.}, journal = {International journal of biological macromolecules}, volume = {225}, number = {}, pages = {923-937}, doi = {10.1016/j.ijbiomac.2022.11.156}, pmid = {36427613}, issn = {1879-0003}, mesh = {Rats ; Animals ; Hydrogels/pharmacology ; *Chitosan/pharmacology ; Alginates/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Hydrogen Peroxide/pharmacology ; Wound Healing ; Anti-Bacterial Agents/pharmacology ; Bandages ; }, abstract = {Microorganisms induced wound infection and the accompanying excessive inflammatory response is the daunting problems in wound treatment. Due to the lack of corresponding biological functions, traditional wound dressings cannot effectively protect the wound and are prone to induce local infection, excessive inflammation, and vascular damage, resulting in prolonged unhealing. Here, a mussel-inspired strategy was adopted to prepare a multifunctional hydrogel created by H2O2/CuSO4-induced rapid polydopamine (PDA) deposition on carboxymethyl chitosan (CMC)/sodium alginate (Alg) based hydrogel, termed as CAC/PDA/Cu(H2O2). The prepared CAC/PDA/Cu(H2O2) hydrogel features excellent biocompatibility, adequate mechanical properties, and good degradability. Moreover, the CAC/PDA/Cu(H2O2) hydrogel can not only realize antibacterial, and anti-inflammatory effects, but also promote angiogenesis to accelerate wound healing in vitro thanks to the composite PDA/Cu(H2O2) coatings. Significantly, CAC/PDA/Cu(H2O2) hydrogel illustrates excellent therapeutic effects in Methicillin-resistant Staphylococcus aureus (MRSA) induced-rat infection models, which can efficiently eliminate MRSA, dramatically reduce inflammatory expression, promote angiogenesis, and ultimately shorten the wound healing time. CAC/PDA/Cu(H2O2) hydrogel exhibited the best wound healing rate on days 7 (80.63 ± 2.44 %), 11 (92.45 ± 2.26 %), and 14 (97.86 ± 0.66 %). Thus, the multifunctional hydrogel provides a facile and efficient approach to wound management and represents promising potential in the therapy for wound healing.}, } @article {pmid36426943, year = {2022}, author = {Menousek, J and Horn, CM and Heim, CE and Van Roy, Z and Korshoj, LE and Kielian, T}, title = {Transcriptional Profiling of Phagocytic Leukocytes and Microglia Reveals a Critical Role for Reactive Oxygen Species in Biofilm Containment during Staphylococcus aureus Craniotomy Infection.}, journal = {Journal of immunology (Baltimore, Md. : 1950)}, volume = {209}, number = {10}, pages = {1973-1986}, pmid = {36426943}, issn = {1550-6606}, support = {R01 NS107369/NS/NINDS NIH HHS/United States ; P20 GM103427/GM/NIGMS NIH HHS/United States ; P30 GM110768/GM/NIGMS NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; }, mesh = {Animals ; Mice ; *Microglia ; Staphylococcus aureus ; Reactive Oxygen Species ; NADPH Oxidase 2 ; Phagocytes ; *Staphylococcal Infections ; Leukocytes ; Biofilms ; Craniotomy ; }, abstract = {Craniotomies are performed to treat a variety of intracranial pathology. Surgical site infection remains a complication of craniotomy despite the use of prophylactic antibiotics and universal sterile precautions. Infections occur in 1-3% of procedures, with approximately half caused by Staphylococcus aureus that forms a biofilm on the bone flap and is recalcitrant to systemic antibiotic therapy. We used an S. aureus-dsRed construct to compare the phagocytic capacity of leukocytes and microglia in vitro and in vivo using a mouse model of craniotomy infection. In addition, single-cell RNA sequencing (scRNA-seq) was applied to determine whether a transcriptional signature could be identified for phagocytic versus nonphagocytic cells in vivo. S. aureus was phagocytosed to equivalent extents in microglia, macrophages, neutrophils, and granulocytic myeloid-derived suppressor cells in vitro; however, microglial uptake of S. aureus was limited in vivo, whereas the other leukocyte populations exhibited phagocytic activity. scRNA-seq comparing the transcriptional signatures of phagocytic (S. aureus-dsRed+) versus nonphagocytic (S. aureus-dsRed-) leukocytes identified classical pathways enriched in phagocytic cells (i.e., reactive oxygen species [ROS]/reactive nitrogen species, lysosome, iron uptake, and transport), whereas nonphagocytic populations had increased ribosomal, IFN, and hypoxia signatures. scRNA-seq also revealed a robust ROS profile, which led to the exploration of craniotomy infection in NADPH oxidase 2 knockout mice. S. aureus burden, leukocyte recruitment, and intracellular bacterial load were significantly increased in NADPH oxidase 2 KO compared with wild-type animals. Collectively, these results highlight the importance of ROS generation in phagocytes for S. aureus biofilm containment, but not clearance, during craniotomy infection.}, } @article {pmid36425609, year = {2022}, author = {Pahlavanzadeh, S and Khoshbakht, R and Kaboosi, H and Moazamian, E}, title = {Phylogenetic relationship, virulence factors, and biofilm formation ability of human, pet animals, and raw milk Staphylococcus aureus isolates.}, journal = {Iranian journal of veterinary research}, volume = {23}, number = {3}, pages = {181-188}, pmid = {36425609}, issn = {1728-1997}, abstract = {BACKGROUND: Identification of genotypic characteristics and pathogenicity of Staphylococcus aureus isolates is very important in the epidemiological study of its related diseases.

AIMS: The present study was done to compare the S. aureus isolates from different sources on the basis of virulence gene properties, biofilm production ability, and phylogenetic variations.

METHODS: Seventy S. aureus isolates (including 25 human, 25 raw milk, and 20 pet animal isolates) were subjected to slime production ability testing, polymerase chain reaction (PCR) detection of 14 different virulence genes, and DNA fingerprinting using restriction fragment length polymorphism (RFLP) of coa gene PCR products.

RESULTS: Among 70 S. aureus, 64 (91.4%) isolates were slime producers on Congo red agar (CRA) medium. The spa and icaD virulence genes were present in all isolates and the seD and etaA genes were not detected in any of the isolates. In total, 22 different virulence gene patterns and nine distinct clusters of coa-PCR-RFLP were identified among isolates.

CONCLUSION: According to the results, S. aureus strains of human origin showed a significant association with specific virulence gene profiles and genotypes. seB and seC were the most responsible genes for S. aureus enterotoxin among human and animal isolates, respectively. Coa-RFLP showed partially appropriate results in the classification and source detection of S. aureus isolates.}, } @article {pmid36425139, year = {2022}, author = {Lenchenko, E and Lenchenko, S and Sachivkina, N and Kuznetsova, O and Ibragimova, A}, title = {Interaction of Cyprinus carpio Linnaeus with the biofilm-forming Aeromonas hydrophila.}, journal = {Veterinary world}, volume = {15}, number = {10}, pages = {2458-2465}, pmid = {36425139}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: The resistance of susceptible fish populations and the adaptive potential of heterogeneous biofilms, which cause multiple antibacterial resistance and long-term persistence of microorganisms, mediate the development and outcome of the infectious process. The study of the fish immunological parameters in interaction with biofilm-forming bacteria is of practical importance for assessing the stability of the homeostasis of the fish. This study aimed to determine the immunobiological parameters of Cyprinus carpio Linnaeus when interacting with biofilm-forming bacteria Aeromonas hydrophila.

MATERIALS AND METHODS: Clinically healthy fish C. carpio L. (Linnaeus, 1758) of both sexes, aged 4 years, and weighing 1.0-1.5 kg (n = 10), were used in this study. The fish were taken from the pond of the VNIIR experimental base in the period of 2020-2022. The standard method was employed to determine the phagocytic activity of blood cells, the total redox activity of neutrophils, and the bactericidal activity of blood serum.

RESULTS: After 24-48 h of cultivation in nutrient broth, the implementation of the processes of intercellular communication of bacteria had common patterns of formation of the heterogeneous structure of biofilms. Moreover, analyzing the optical density indices (density, D), it was observed that A. hydrophila was a strong producer of biofilms, as the optical density of the sample (density of sample, Ds) exceeded the optical density of the control (density of control, Dc) by more than 4 times (D = 0.464 ± 0.07). The ratio of the average number of microorganisms attached to the surface of one erythrocyte (average adhesion index) and the percentage (%) of erythrocytes having bacteria on their surface (adhesion coefficient [AC]) was 14.05 ± 0.72, and the adhesion index, AI was ≥4.00, indicating A. hydrophila to be highly adhesive. In addition, the AC of erythrocytes having bacteria on the surface was 14.05% ± 0.72%. A direct correlation was established (R[2] = 0.94) between the AC (14.05% ± 0.11%-13.29% ± 0.08%) and the phagocytic index (11.3% ± 0.29%-32.0% ± 0.8%). The indicators of spontaneous nitro blue tetrazolium were 103.20 ± 11.70 when estimating the total redox activity of neutrophils. The optical density increased to 182.10 ± 21.12 with the addition of 20.0 mL of A. hydrophila bacteria (1 billion/mL) and the activity of neutrophils also increased.

CONCLUSION: Among the markers of homeostasis stability, immunological indicators most fully reflect the mechanisms of initiation, development, and outcome of the infectious process mediated by the interaction of adhesive molecules of multicellular eukaryotes and adhesives of infectious disease pathogens. The research will contribute to further understanding the potential mechanism of quorum-sensing molecules and the search for new anti-adhesive drugs that reduce the formation of biofilms.}, } @article {pmid36425031, year = {2022}, author = {Zhang, M and Han, W and Gu, J and Qiu, C and Jiang, Q and Dong, J and Lei, L and Li, F}, title = {Recent advances on the regulation of bacterial biofilm formation by herbal medicines.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1039297}, pmid = {36425031}, issn = {1664-302X}, abstract = {Biofilm formation is a fundamental part of life cycles of bacteria which affects various aspects of bacterial-host interactions including the development of drug resistance and chronic infections. In clinical settings, biofilm-related infections are becoming increasingly difficult to treat due to tolerance to antibiotics. Bacterial biofilm formation is regulated by different external and internal factors, among which quorum sensing (QS) signals and nucleotide-based second messengers play important roles. In recent years, different kinds of anti-biofilm agents have been discovered, among which are the Chinese herbal medicines (CHMs). CHMs or traditional Chinese medicines have long been utilized to combat various diseases around the world and many of them have the ability to inhibit, impair or decrease bacterial biofilm formation either through regulation of bacterial QS system or nucleotide-based second messengers. In this review, we describe the research progresses of different chemical classes of CHMs on the regulation of bacterial biofilm formation. Though the molecular mechanisms on the regulation of bacterial biofilm formation by CHMs have not been fully understood and there are still a lot of work that need to be performed, these studies contribute to the development of effective biofilm inhibitors and will provide a novel treatment strategy to control biofilm-related infections.}, } @article {pmid36424663, year = {2022}, author = {Wang, Q and Shi, Q and Li, Y and Lu, S and Xie, X}, title = {Visible light-regulated cationic polymer coupled with photodynamic inactivation as an effective tool for pathogen and biofilm elimination.}, journal = {Journal of nanobiotechnology}, volume = {20}, number = {1}, pages = {492}, pmid = {36424663}, issn = {1477-3155}, support = {2020GDASYL-20200103030//GDAS' Project of Science and Technology Development/ ; }, mesh = {*Photosensitizing Agents/pharmacology ; Polymers/pharmacology ; *Photochemotherapy/methods ; Biofilms ; Light ; Cations/pharmacology ; }, abstract = {BACKGROUND: Pathogenic microorganism pollution has been a challenging public safety issue, attracting considerable scientific interest. A more problematic aspect of this phenomenon is that planktonic bacteria exacerbate biofilm formation. There is an overwhelming demand for developing ultra-efficient, anti-drug resistance, and biocompatibility alternatives to eliminate stubborn pathogenic strains and biofilms.

RESULTS: The present work aims to construct a visible light-induced anti-pathogen agents to ablate biofilms using the complementary merits of ROS and cationic polymers. The photosensitizer chlorin e6-loaded polyethyleneimine-based micelle (Ce6-TPP-PEI) was constructed by an amphiphilic dendritic polymer (TPP-PEI) and physically loaded with photosensitizer chlorin e6. Cationic polymers can promote the interaction between photosensitizer and Gram-negative bacteria, resulting in enhanced targeting of PS and lethality of photodynamic therapy, and remain active for a longer duration to prevent bacterial re-growth when the light is turned off. As expected, an eminent antibacterial effect was observed on the Gram-negative Escherichia coli, which is usually insensitive to photosensitizers. Surprisingly, the cationic polymer and photodynamic combination also exert significant inhibitory and ablative effects on fungi and biofilms. Subsequently, cell hemolysis assessments suggested its good biocompatibility.

CONCLUSIONS: Given the above results, the platform developed in this work is an efficient and safe tool for public healthcare and environmental remediation.}, } @article {pmid36423527, year = {2023}, author = {Arroussi, M and Zhao, J and Bai, C and Zhang, S and Xia, Z and Jia, Q and Yang, K and Yang, R}, title = {Evaluation of inhibition effect on microbiologically influenced corrosion of Ti-5Cu alloy against marine Bacillus vietnamensis biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {149}, number = {}, pages = {108265}, doi = {10.1016/j.bioelechem.2022.108265}, pmid = {36423527}, issn = {1878-562X}, mesh = {*Alloys/pharmacology ; Corrosion ; *Titanium/pharmacology ; Materials Testing ; Biofilms ; Surface Properties ; }, abstract = {Titanium is highly susceptible to biofouling due to the poor toxicity and excellent biocompatibility. Microbiologically influenced corrosion of cp-Ti induced by Bacillus vietnamensis and the inhibition effect of Ti-5Cu alloy were evaluated using various electrochemical techniques and surface analyses. Electrochemical results revealed that, cp-Ti and Ti-5Cu alloy exhibited excellent passivation in the sterile medium. In biotic medium, however, attachment of B. vietnamensis biofilm to surface of cp-Ti accelerated the active dissolution and poisons repassivation. In contrast, cells adhered preferentially as a form of discrete colonies on Ti2Cu intermetallic phases. Release of Cu[2+] ions induced damage in morphology of B. vietnamensis cells resulting in relative resistance to pitting corrosion estimated by 3.1 ± 0.6 µm and 2.0 ± 0.4 µm for cp-Ti and Ti-5Cu alloy, respectively.}, } @article {pmid36422359, year = {2022}, author = {Amato, M and Di Spirito, F and D'Ambrosio, F and Boccia, G and Moccia, G and De Caro, F}, title = {Probiotics in Periodontal and Peri-Implant Health Management: Biofilm Control, Dysbiosis Reversal, and Host Modulation.}, journal = {Microorganisms}, volume = {10}, number = {11}, pages = {}, pmid = {36422359}, issn = {2076-2607}, abstract = {Periodontitis and peri-implantitis are microbially associated diseases of the tissues supporting the teeth and dental implants that are mediated by host inflammation and eventually lead to tooth and dental implant loss. Given the probiotics' role in biofilm control, dysbiosis reversal, and host modulation, their potential beneficial effects on the improvement of periodontitis and peri-implantitis have been recently investigated. Moreover, probiotics use has also been proposed in periodontal health management in patients undergoing fixed orthodontic therapy. Therefore, the present study aimed to review, considering the periodontal microbiome composition around teeth and dental implants in healthy and pathological conditions, the putative favorable effects of probiotics on gingivitis, periodontitis, and peri-implantitis. The secondary aim of the present narrative review was to synthesize the supporting evidence and proposed protocols for probiotics use as adjuncts in periodontitis and peri-implantitis treatment and the periodontal health management of orthodontic patients with fixed appliances. Contrasting findings from the literature may be due to the different methods, posology, and duration of probiotics prescriptions and due to the heterogeneous biological and clinical measurement methods employed. Thus, no definitive conclusions could be drawn about the effectiveness of probiotics in periodontal management, both in healthy and pathological conditions. Further studies are needed to validate probiotics for periodontal management and provide recommended protocols.}, } @article {pmid36422349, year = {2022}, author = {Srichaiyapol, O and Maddocks, SE and Thammawithan, S and Daduang, S and Klaynongsruang, S and Patramanon, R}, title = {TA-AgNPs/Alginate Hydrogel and Its Potential Application as a Promising Antibiofilm Material against Polymicrobial Wound Biofilms Using a Unique Biofilm Flow Model.}, journal = {Microorganisms}, volume = {10}, number = {11}, pages = {}, pmid = {36422349}, issn = {2076-2607}, support = {PHD/0092/2560//National Research Council of Thailand/ ; }, abstract = {The presence of biofilm within a chronic wound may delay the healing process. Thus, control of biofilm formation and providing bactericidal effect are crucial factors for wound healing management. Alginate-based nanocomposite hydrogels have been suggested as dressing materials for wound treatment, which are employed as a biocompatible matrix. Therefore, in this study, we aimed to develop a biocompatible antimicrobial wound dressing containing AgNPs and demonstrate its efficacy against polymicrobial wound biofilms by using a biofilm flow device to simulate a chronic infected, exuding wound and specific wound environment. The results from agar well diffusion, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays showed that TA-AgNPs exhibited antibacterial activity against wound pathogens. Additionally, the Minimum Biofilm Eradication Concentration assay (MBEC) demonstrated it could impair biofilm formation. Importantly, our TA-AgNPs/Alginate hydrogel clearly showed antibacterial activities against Streptococcus pyogenes, Staphylococcus aureus and Pseudomonas aeruginosa. Furthermore, we used the biofilm flow device to test the topical antimicrobial hydrogel against a three-species biofilm. We found that TA-AgNPs/Alginate hydrogel significantly showed a 3-4 log reduction in bacterial numbers when applied with multiple doses at 24 h intervals, and was especially effective against the chronic wound pathogen P. aeruginosa. This work highlighted that the TA-AgNPs/Alginate hydrogel is a promising material for treating complex wound biofilms.}, } @article {pmid36422037, year = {2022}, author = {Costa, PS and Cruz, E and Veiga, F and Jarros, IC and Negri, M and Svidzinski, TIE}, title = {Efficacy of Propolis Gel on Mature Biofilm Formed by Neocosmospora keratoplastica Isolated from Onychomycosis.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {11}, pages = {}, pmid = {36422037}, issn = {2309-608X}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 308624/2019-0//National Council for Scientific and Technological Development/ ; }, abstract = {This article describes Neocosmospora keratoplastica as an etiological onychomycosis agent. Ex vivo studies were initially performed to demonstrate the ability of this species to grow and form a well-organized characteristic biofilm on sterilized healthy nails. Based on the history of excellent results, both for antifungal and antibiofilm, of propolis resin gum, we evaluated its activity using artificially formed biofilm. In vitro, the minimal biofilm eradication concentration of the propolis extract (PE) was 375 µg of total polyphenol content (TPC) per mL, while for the propolis gel (PG) it was 450 µg of TPC per mL. In biofilm exposed to the propolis products, a decrease in hyphae and conidia was evident, accompanied by a disorganization of the extracellular matrix. Additionally, this low concentration of PE was able to significantly reduce the number of colony-forming units and the metabolic activity. Furthermore, the treatment of a 15-year nail infection due to N. keratoplastica was carried out exclusively using a topical treatment with a gel containing propolis (30%) with a daily dosage. This treatment achieved complete remission of the onychomycosis in 12 months. It is important to point out that some inconveniences previously reported by other patients treated with propolis extract were eliminated, increasing adherence to treatment.}, } @article {pmid36422031, year = {2022}, author = {Čonková, E and Proškovcová, M and Váczi, P and Malinovská, Z}, title = {In Vitro Biofilm Formation by Malassezia pachydermatis Isolates and Its Susceptibility to Azole Antifungals.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {11}, pages = {}, pmid = {36422031}, issn = {2309-608X}, support = {No. APVV-15-0377//Slovak Research and Development Agency/ ; }, abstract = {The yeast Malassezia pachydermatis, an opportunistic pathogen that inhabits the skin of various domestic and wild animals, is capable of producing a biofilm that plays an important role in antifungal resistance. The aim of this research study was to find the intensity of biofilm production by M. pachydermatis strains isolated from the ear canal of healthy dogs, and to determine the susceptibility of planktonic, adhered and biofilm-forming cells to three azole antifungals-itraco-nazole, voriconazole and posaconazole-that are most commonly used to treat Malassezia infections. Out of 52 isolates, 43 M. pachydermatis strains (82.7%) were biofilm producers with varying levels of intensity. For planktonic cells, the minimum inhibitory concentration (MIC) range was 0.125-2 µg/mL for itraconazole, 0.03-1 µg/mL for voriconazole and 0.03-0.25 µg/mL for posaconazole. Only two isolates (4.7%) were resistant to itraconazole, one strain (2.3%) to voriconazole and none to posaconazole. For adhered cells and the mature biofilm, the following MIC ranges were found: 0.25-16 µg/mL and 4-16 µg/mL for itraconazole, 0.125-8 µg/mL and 0.25-26 µg/mL for voriconazole, and 0.03-4 µg/mL and 0.25-16 µg/mL for posaconazole, respectively. The least resistance for adhered cells was observed for posaconazole (55.8%), followed by voriconazole (62.8%) and itraconazole (88.4%). The mature biofilm of M. pachydermatis showed 100% resistance to itraconazole, 95.3% to posaconazole and 83.7% to voriconazole. The results of this study show that higher concentrations of commonly used antifungal agents are needed to control infections caused by biofilm-forming strains of M. pachydermatis.}, } @article {pmid36422006, year = {2022}, author = {Champion, M and Portier, E and Vallée-Réhel, K and Linossier, I and Balnois, E and Vignaud, G and Moppert, X and Hellio, C and Faÿ, F}, title = {Anti-Biofilm Activity of a Hyaluronan-like Exopolysaccharide from the Marine Vibrio MO245 against Pathogenic Bacteria.}, journal = {Marine drugs}, volume = {20}, number = {11}, pages = {}, pmid = {36422006}, issn = {1660-3397}, support = {CDE//University of Southern Brittany/ ; BIOPS 1712//Regional Council of Brittany/ ; 2020-00200//Pacificbiotech/ ; }, mesh = {*Hyaluronic Acid/pharmacology ; Biofilms ; *Vibrio ; Quorum Sensing ; Pseudomonas ; }, abstract = {Biofilms, responsible for many serious drawbacks in the medical and marine environment, can grow on abiotic and biotic surfaces. Commercial anti-biofilm solutions, based on the use of biocides, are available but their use increases the risk of antibiotic resistance and environmental pollution in marine industries. There is an urgent need to work on the development of ecofriendly solutions, formulated without biocidal agents, that rely on the anti-adhesive physico-chemical properties of their materials. In this context, exopolysaccharides (EPSs) are natural biopolymers with complex properties than may be used as anti-adhesive agents. This study is focused on the effect of the EPS MO245, a hyaluronic acid-like polysaccharide, on the growth, adhesion, biofilm maturation, and dispersion of two pathogenic model strains, Pseudomonas aeruginosa sp. PaO1 and Vibrio harveyi DSM19623. Our results demonstrated that MO245 may limit biofilm formation, with a biofilm inhibition between 20 and 50%, without any biocidal activity. Since EPSs have no significant impact on the bacterial motility and quorum sensing factors, our results indicate that physico-chemical interactions between the bacteria and the surfaces are modified due to the presence of an adsorbed EPS layer acting as a non-adsorbing layer.}, } @article {pmid36421919, year = {2022}, author = {Koegel, S and Braissant, O and Waltimo, T and Bornstein, MM and Astasov-Frauenhoffer, M}, title = {Evaluation of antibacterial properties of fluoride-containing mouth rinses differing in their acidic compound using a Streptococcus mutans biofilm.}, journal = {Swiss dental journal}, volume = {133}, number = {}, pages = {}, pmid = {36421919}, issn = {2296-6498}, abstract = {This in vitro study assessed the antibacterial effect on Streptococcus mutans biofilms of mouth rinses with 700 ppm F- (derived from NaF) that differed only in their acid compounds (malic (A), citric (B), tartaric (C), fumaric (D), hydrochloric (E), phosphoric (F), and lactic (G) acid) used to adjust pH. S. mutans (ATCC 25175) was grown for 22 h at 37°C, harvested, resuspended in simulated body fluid and biofilm formation followed for 24 h at 37°C. Thereafter, biofilms were treated with experimental rinses for 30 s, and placed in TAM48 isothermal microcalorimeter at 37°C for 72 h. Applying Gompertz growth model parameters lag time and growth rate were determined from heatflow curves; additionally, reduction of active biofilms was calculated. Moreover, samples were live/dead stained and analyzed by confocal scanning microscopy. All mouth rinses were showing statistically significant lag time and reduction of active biofilm (p<0.05, A 19.1+/-2.3h and 58.5+/-7.7%, B 15.5+/-1.1h and 41.9+/-5.3%, C 17.6+/-1.9h and 53.1+/-7.5%, D 18.4+/-2.4h and 55.8+/-8.8%, E 20.2+/-3.3h and 61.5+/-10.0%, F 20.2+/-3.0h and 61.6+/-9.3%, and G 18.3+/-2.5h and 55.3+/-8.9%). Interestingly, there were no differences found between the treated groups (p>0.05, A 0.064+/-0.004 1/h, B 0.063+/-0.005 1/h, C 0.065+/-0.004 1/h, D 0.067+/-0.004 1/h, E 0.066+/-0.006 1/h, F 0.067+/-0.004 1/h, G 0.066+/-0.006 1/h) for the maximum growth rate. Vitality staining supported these findings.. The present investigation demonstrates that the type of acid compounds used to produce the rinses did not show any negative effect on the antimicrobial properties of the tested products as all of them exhibited a similar efficacy against S. mutans biofilms.}, } @article {pmid36421310, year = {2022}, author = {Ballah, FM and Islam, MS and Rana, ML and Ullah, MA and Ferdous, FB and Neloy, FH and Ievy, S and Sobur, MA and Rahman, AT and Khatun, MM and Rahman, M and Rahman, MT}, title = {Virulence Determinants and Methicillin Resistance in Biofilm-Forming Staphylococcus aureus from Various Food Sources in Bangladesh.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36421310}, issn = {2079-6382}, support = {TETFund/2020//Tertiary Education Trust Fund, Nigeria/ ; 2019/8/BAU//Bangladesh Agricultural University Research System (BAURES)/ ; }, abstract = {The eradication of staphylococcal infections has become more difficult due to the development of antibiotic resistance and virulence in biofilm-forming Staphylococcus aureus. The presence of the life-threatening zoonotic pathogen, methicillin-resistant S. aureus (MRSA), in foods indicates a public health issue. This study, therefore, aimed to determine virulence factors and methicillin resistance in biofilm-forming S. aureus isolates from different foods and food handlers. A total of 100 PCR-positive S. aureus isolates (97 biofilm formers and three non-biofilm formers) were screened using the disk diffusion method and PCR assay. By PCR, genes encoding virulence factors, e.g., enterotoxin (sea, 30%, 95% CI: 21.90−39.59%), toxic shock syndrome toxin (tst, 20%, 95% CI: 13.34−28.88%), and Panton−Valentine leukocidin toxin (PVL, 15%, 95% CI: 9.31−23.28%), were detected in the S. aureus isolates. By the disk diffusion method, 100% (95% CI: 96.30−100.00%) of S. aureus isolates were phenotypically MRSA in nature, showing 100% resistance to oxacillin and cefoxitin. Moreover, the methicillin-resistant gene mecA was found in 61 (61%, 95% CI: 51.20−69.98%) MRSA isolates. Furthermore, all the S. aureus isolates were phenotypically resistant to ampicillin and penicillin, 30% to erythromycin, and 11% to gentamycin. Among them, 51% (95% CI: 41.35−60.58%) of S. aureus isolates were phenotypically multidrug-resistant in nature, and the multiple antibiotic resistance index varied from 0.33 to 0.55. Genes encoding resistance to beta-lactams (blaZ, 100%, 95% CI: 96.30−100.00%) and tetracyclines (tetA and tetC, 3%, 95% CI: 0.82−8.45%) were found positive in the S. aureus isolates. Genes encoding virulence determinants and MRSA were significantly (p < 0.05) higher in strong biofilm-forming S. aureus than in moderate and non-biofilm-forming isolates. To our knowledge, this is the first study in Bangladesh to incorporate preliminary data on the occurrence of virulence determinants and methicillin resistance, including resistance to clinically important antibiotics, in biofilm-forming S. aureus isolates from different foods and food handlers in Bangladesh, emphasizing a potential threat to human health.}, } @article {pmid36421300, year = {2022}, author = {Liu, X and Wang, Y and Zaleta-Pinet, DA and Borris, RP and Clark, BR}, title = {Antibacterial and Anti-Biofilm Activity of Pyrones from a Pseudomonas mosselii Strain.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36421300}, issn = {2079-6382}, support = {81850410550//National Natural Science Foundation of China/ ; LHGJ20220216//Health Commission of Henan Province/ ; B2022209034//Natural Science Foundation of Hebei Province/ ; }, abstract = {The emergence of drug resistant microbes over recent decades represents one of the greatest threats to human health; the resilience of many of these organisms can be attributed to their ability to produce biofilms. Natural products have played a crucial role in drug discovery, with microbial natural products in particular proving a rich and diverse source of antimicrobial agents. During antimicrobial activity screening, the strain Pseudomonas mosselii P33 was found to inhibit the growth of multiple pathogens. Following chemical investigation of this strain, pseudopyronines A-C were isolated as the main active principles, with all three pseudopyronines showing outstanding activity against Staphylococcus aureus. The analogue pseudopyronine C, which has not been well-characterized previously, displayed sub-micromolar activity against S. aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. Moreover, the inhibitory abilities of the pseudopyronines against the biofilms of S. aureus were further studied. The results indicated all three pseudopyronines could directly reduce the growth of biofilm in both adhesion stage and maturation stage, displaying significant activity at micromolar concentrations.}, } @article {pmid36421291, year = {2022}, author = {Spiegel, C and Nogler, M and Coraça-Huber, DC}, title = {Sterilization Procedures for Titanium Alloy Surfaces Leads to Higher Expression of Biofilm-Related Staphylococcus aureus Genes.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36421291}, issn = {2079-6382}, abstract = {Background: Around 1-2% of all implantation surgeries lead to implant-related infections, incurring costs of $40,000-$160,000 per total hip PJI. The 5-year mortality rate of prosthetic joint infections is up to 21%. To prevent infections during surgery, sterile surgery rooms and procedures have been developed and certified standards have been established. To guarantee the sterility, implants can be acquired already sterile from manufacturers. Some titanium implants can be delivered unsterilized with a manual for sterilization procedure in compliance with ISO 17664. The aim of this study is to evaluate if the most used sterilization methods (steam sterilization in an autoclave and UV light sterilization) of titanium alloys, can influence the biofilm forming capacity of Staphylococcus aureus. In this study, we examined the influence of sterilization methods on the gene expression of biofilm-associated genes and regulators. Methods: We compared gene expression of icaADBC, SarA, SigB, and SodA on titanium CP4 and Ti6Al4V alloys sterilized by UV-light and pressurized saturated steam sterilization. We performed RT-qPCR after RNA extraction of Staphylococcus aureus ATCC 29213. In addition, bacterial cell growth on the sterilized titanium surfaces was examined by colony forming unit counting on agar plates after 24 h of incubation. Results: Colony forming units of S. aureus on titanium CP4 samples showed a higher tendency in colony counts when sterilized with UV light than with pressurized saturated steam (autoclaved). Similarly, colony forming unit counts on Ti6Al4V samples showed tendencies of higher numbers on UV light sterilized samples than on autoclaved samples. Gene expression of icaADBC, SarA and SodA between steamed samples and UV light sterilized samples showed no difference on titanium CP4 samples, whereas SigB showed higher gene expression on titanium CP4 samples when sterilized with UV light than in an autoclave. On autoclaved Ti6Al4V samples, all examined genes showed 4 to 9 times higher fold changes in gene expression than on UV light sterilized samples. Conclusions: This study indicates that steam sterilization of Ti6Al4V can increase biofilm formation of S. aureus on its surface. The significantly increased gene expression of biofilm responsible genes may indicate a modification of titanium surfaces on alloy components. This may promote biofilm formation that can lead to implant-infections in vivo.}, } @article {pmid36421241, year = {2022}, author = {Hamion, G and Aucher, W and Tardif, C and Miranda, J and Rouger, C and Imbert, C and Girardot, M}, title = {Valorization of Invasive Plant Extracts against the Bispecies Biofilm Staphylococcus aureus-Candida albicans by a Bioguided Molecular Networking Screening.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36421241}, issn = {2079-6382}, support = {AAPR2020-2019-8408110 - Research Grant//Region Nouvelle-Aquitaine/ ; ANR-11-INBS-0010//Bordeaux Metabolome Facility/ ; AAP ARIC 2019 Research grant//University of Poitiers and University of Limoges/ ; XX//2015-2020 State-Region Planning Contracts (CPER)/ ; XX//European Regional Development Fund (FEDER)/ ; XX//Centre National de la Recherche Scientifique/ ; }, abstract = {Invasive plants efficiently colonize non-native territories, suggesting a great production of bioactive metabolites which could be effective antibiofilm weapons. Our study aimed to look for original molecules able to inhibit bispecies biofilm formed by S. aureus and C. albicans. Extracts from five invasive macrophytes (Ludwigia peploides, Ludwigia grandiflora, Myriophyllum aquaticum, Lagarosiphon major and Egeria densa) were prepared and tested in vitro against 24 h old bispecies biofilms using a crystal violet staining (CVS) assay. The activities of the extracts reducing the biofilm total biomass by 50% or more were comparatively analyzed against each microbial species forming the biofilm by flow cytometry (FCM) and scanning electron microscopy. Extracts active against both species were fractionated. Obtained fractions were analyzed by UHPLC-MS/MS and evaluated by the CVS assay. Chemical and biological data were combined into a bioactivity-based molecular networking (BBMN) to identify active compounds. The aerial stem extract of L. grandiflora showed the highest antibiofilm activity (>50% inhibition at 50 µg∙mL−1). The biological, chemical and BBMN investigations of its fractions highlighted nine ions correlated with the antibiofilm activity. The most correlated compound, identified as betulinic acid (BA), inhibited bispecies biofilms regardless of the three tested couples of strains (ATCC strains: >40% inhibition, clinical isolates: ≈27% inhibition), confirming its antibiofilm interest.}, } @article {pmid36420183, year = {2022}, author = {Dawadi, P and Khanal, S and Prasai Joshi, T and Kc, S and Tuladhar, R and Maharjan, BL and Darai, A and Joshi, DR}, title = {Antibiotic Resistance, Biofilm Formation and Sub-Inhibitory Hydrogen Peroxide Stimulation in Uropathogenic Escherichia coli.}, journal = {Microbiology insights}, volume = {15}, number = {}, pages = {11786361221135224}, pmid = {36420183}, issn = {1178-6361}, abstract = {Uropathogenic Escherichia coli (UPEC) is the most prevalent cause of urinary tract infections (UTIs). Biofilm formation and antibiotic resistance could be high among the causative agent. The purpose of this study was to determine antibiotic resistance, biofilm production, and biofilm-associated genes, bcsA and csgD, and sub-inhibitory hydrogen peroxide (H2O2) stimulation in UPEC for biofilm formation. A total of 71 UPEC were collected from a tertiary care hospital in Kathmandu and subjected to identify antibiotic susceptibility using Kirby-Bauer disk diffusion. The biofilm formation was assessed using microtiter culture plate method while pellicle formation was tested by a tube method. In representative 15 isolates based on biofilm-forming ability, bcsA and csgD were screened by conventional polymerase chain reaction, and treated with sub-lethal H2O2. The UPEC were found the most susceptible to meropenem (90.2%), and the least to ampicillin (11.3%) in vitro and 90.1% of them were multi-drug resistant (MDR). Most UPEC harbored biofilm-producing ability (97.2%), and could form pellicle at 37°C. Among representative 15 isolates, csgD was detected only among 10 isolates (66.67%) while bcsA gene was present in 13 isolates (86.67%). This study revealed that level of biofilm production elevated after sub-lethal H2O2 treatment (P = .041). These findings suggested that the pathogens are emerging as MDR. The biofilm production is high and the majority of selected strains contained bcsA and csgD genes. Pellicle formation test was suggestive to be an alternative qualitative method to screen biofilm production in UPEC. The sub-inhibitory concentration of H2O2 may contribute in increasing biofilm formation in UPEC.}, } @article {pmid36419597, year = {2022}, author = {Mamun, MAA and Nasren, S and Abhiman, PB and Rathore, SS and Rakesh, K and Sowndarya, NS and Ramesh, KS and Shankar, KM}, title = {Evaluation of feed utilization, immune response and disease resistance in striped catfish, Pangasianodon hypophthalmus (Sauvage 1878) fed with a novel Aeromonas hydrophila biofilm vaccine.}, journal = {Fish and shellfish immunology reports}, volume = {3}, number = {}, pages = {100070}, pmid = {36419597}, issn = {2667-0119}, abstract = {Striped catfish, Pangasianodon hypophthalmus was immunized with Biofilm (BF) and Free cell (FC) of Aeromonas hydrophila vaccine at 10[10] CFU g[-1] for 20 days and monitored for growth parameters, immune responses and disease resistance up to 60 day post vaccination (dpv). Pangasius catfish in the BF vaccinated group had considerably higher growth and feed utilization than the FC vaccinated and unvaccinated groups (p < 0.05). Biofilm vaccinated group showed a significant increase (p < 0.05) in the mean weight gain (46.91 ± 0.59) than the FC (35.94 ± 0.21) and unvaccinated group (34.92 ± 0.35). The vaccinated fishes were challenged with A. hydrophila at 10[7] CFU/ml. Significant higher relative percentage survival (RPS) was recorded with BF (84.21 ± 1.49%) compared to that with FC (33.33 ± 1.21%). Polyclonal antibody-based ELISA was used to quantify the antibody titre. BF vaccinated group showed significantly higher antibody titer compared to other treatments (p < 0.05). Moreover, higher haematological parameters recorded in the present study were differentially stimulated by the oral administration of A. hydrophila biofilm vaccine. The mean total protein, albumin, and globulin levels of the BF vaccine groups were significantly higher (p < 0.05) than the mean total protein, albumin, and globulin contents of the unvaccinated group. Furthermore, biochemical stress parameters (SGPT, SGOT) in the vaccinated groups showed an incremental trend in the early days of the experimental period. However, the values were significantly lower (p < 0.05) in the biofilm group on 20 dpv onwards indicating improved health condition. Vaccinated BF fishes showed gut associated lymphoid tissues (GALT) within the laminar propria of mid gut. But in FC group fishes showed less aggregation of lymphoid cells. The unvaccinated control fish had no lymphoid cell aggregation in their intestines. The findings of the current research suggested that biofilm vaccine has the capability to be one of the potential oral vaccines in striped catfish against A. hydrophila infection.}, } @article {pmid36418899, year = {2022}, author = {Shibamura-Fujiogi, M and Wang, X and Maisat, W and Koutsogiannaki, S and Li, Y and Chen, Y and Lee, JC and Yuki, K}, title = {GltS regulates biofilm formation in methicillin-resistant Staphylococcus aureus.}, journal = {Communications biology}, volume = {5}, number = {1}, pages = {1284}, pmid = {36418899}, issn = {2399-3642}, support = {R01GM127600/GM/NIGMS NIH HHS/United States ; }, mesh = {*Methicillin-Resistant Staphylococcus aureus/genetics ; Biofilms ; Cell Aggregation ; Glutamic Acid ; Urea ; }, abstract = {Biofilm-based infection is a major healthcare burden. Methicillin-resistant Staphylococcus aureus (MRSA) is one of major organisms responsible for biofilm infection. Although biofilm is induced by a number of environmental signals, the molecule responsible for environmental sensing is not well delineated. Here we examined the role of ion transporters in biofilm formation and found that the sodium-glutamate transporter gltS played an important role in biofilm formation in MRSA. This was shown by gltS transposon mutant as well as its complementation. The lack of exogenous glutamate also enhanced biofilm formation in JE2 strain. The deficiency of exogenous glutamate intake accelerated endogenous glutamate/glutamine production, which led to the activation of the urea cycle. We also showed that urea cycle activation was critical for biofilm formation. In conclusion, we showed that gltS was a critical regulator of biofilm formation by controlling the intake of exogenous glutamate. An intervention to target glutamate intake may be a potential useful approach against biofilm.}, } @article {pmid36418689, year = {2023}, author = {Brown, JL and Butcher, MC and Veena, CLR and Chogule, S and Johnston, W and Ramage, G}, title = {Generation of Multispecies Oral Bacteria Biofilm Models.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2588}, number = {}, pages = {187-199}, pmid = {36418689}, issn = {1940-6029}, mesh = {*Biofilms ; *Microbiota ; Bacteria ; Mouth/microbiology ; Models, Biological ; }, abstract = {It is well-recognized that oral biofilms that occur in health and disease have a polymicrobial composition, though these are poorly reflected in the literature, with many studies focussing on simple mono-species biofilm model systems. The utility of polymicrobial biofilm model systems is that they more accurately reflect the oral cavity and allow researchers to ask relevant questions in basic science studies, pharmaceutical screening, and investigating inflammatory interactions. Here we describe the detailed methodology of how to sequentially construct and maintain polymicrobial biofilm models pertinent to caries, periodontal disease, and denture stomatitis.}, } @article {pmid36417577, year = {2023}, author = {Qiao, Y and Ma, Y and Tong, Y and Liu, W and Wang, S and Zheng, Y and Men, C and Yu, J and Pan, J and Wan, D and Yin, Y and Zhao, X and Xi, R and Meng, M}, title = {Phototherapy and Mechanism Exploration of Biofilm and Multidrug-Resistant Helicobacter pylori by Bacteria-Targeted NIR Photosensitizer.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {19}, number = {4}, pages = {e2205248}, doi = {10.1002/smll.202205248}, pmid = {36417577}, issn = {1613-6829}, mesh = {Humans ; *Helicobacter pylori ; Photosensitizing Agents/pharmacology/therapeutic use ; Phototherapy ; Biofilms ; *Photochemotherapy ; *Helicobacter Infections/drug therapy/microbiology ; Anti-Bacterial Agents/pharmacology/therapeutic use ; }, abstract = {Helicobacter pylori (H. pylori) infection has been the leading cause of gastric cancer development. In recent years, the resistance of H. pylori against antibiotic treatment has been a great challenge for most countries worldwide. Since biofilm formation is one of the reasons for the antibiotic resistance of H. pylori, and phototherapy has emerged as a promisingly alternative antibacterial treatment, herein the bacteria-targeted near-infrared (NIR) photosensitizer (T780T-Gu) by combining positively-charged guanidinium (Gu) with an efficient phototherapeutic agent T780T is developed. The proposed molecule T780T-Gu exhibits synergistic photothermal therapy/photodynamic therapy effect against both H. pylori biofilms and multidrug-resistant (MDR) clinical strains. More importantly, the phototherapy mechanism of T780T-Gu acquired by the RNA-seq analysis indicates that structural deficiency as well as a decrease in metabolism and defense activity are the possible reasons for the efficient H. pylori phototherapy.}, } @article {pmid36416971, year = {2022}, author = {Nakamura, T and Yonezawa, H and Kawarai, T and Narisawa, N and Senpuku, H}, title = {Inhibitory effect of the combination of xylitol and funoran on Streptococcus mutans biofilm formation on the uncoated surface.}, journal = {Archives of microbiology}, volume = {204}, number = {12}, pages = {723}, pmid = {36416971}, issn = {1432-072X}, support = {16K11537//Ministry of Education, Culture, Sports, Science and Technology/ ; 20K10286//Ministry of Education, Culture, Sports, Science and Technology/ ; 40105502//Japan Agency for Medical Research and Development/ ; }, mesh = {Aged ; Humans ; *Xylitol/pharmacology ; Streptococcus mutans ; *Dental Caries/prevention & control ; Biofilms ; }, abstract = {We investigated the effect of xylitol or/and funoran on biofilm formation by Streptococcus mutans, one of cariogenic bacteria, on the surfaces coated and non-coated with saliva. Effects of xylitol and/or funoran were observed on biofilm formation of S. mutans in non-coated and salivary components-coated polystyrene microtiter 96-well plates (s-plate) and flow cell system. Xylitol did not strongly affect biofilm formation of S. mutans UA159 on non-coated and s-plates and, however, changed the quality of the biofilm on the cells in a flow cell system. Funoran had effects on biofilm formation, and the combination of xylitol and funoran strongly inhibited S. mutans biofilm formation on non-coated plates. In particular, funoran had inactivation effects on membrane vesicles (MVs) and inhibited MV-dependent biofilm formation of S. mutans on non-coated plate surfaces but not on the s-plate. These findings suggest that the combination of xylitol and funoran might be useful to remove the oral biofilm formation in elderly individuals with decreased saliva production. This result suggests that the synergistic effect of funoran and xylitol might be useful for the prevention of biofilm-associated diseases such as dental caries in saliva-decreased patients such as elderly patients.}, } @article {pmid36416583, year = {2022}, author = {Wang, WH and Lai, TX and Wu, YC and Chen, ZT and Tseng, KY and Lan, CY}, title = {Associations of Rap1 with Cell Wall Integrity, Biofilm Formation, and Virulence in Candida albicans.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0328522}, pmid = {36416583}, issn = {2165-0497}, mesh = {*Antifungal Agents/therapeutic use ; Biofilms ; *Candida albicans/genetics/metabolism ; Cell Wall/metabolism ; Fungal Proteins/genetics/metabolism ; Virulence ; Animals ; Moths ; }, abstract = {Rap1 (repressor activator protein 1) is a multifunctional protein, playing important roles in telomeric and nontelomeric functions in many eukaryotes. Candida albicans Rap1 has been previously shown to be involved in telomeric regulation, but its other functions are still mostly unknown. In this study, we found that the deletion of the RAP1 gene altered cell wall properties, composition, and gene expression. In addition, deletion of RAP1 affected C. albicans biofilm formation and modulated phagocytosis and cytokine release by host immune cells. Finally, the RAP1 gene deletion mutant showed attenuation of C. albicans virulence in a Galleria mellonella infection model. Therefore, these findings provide new insights into Rap1 functions that are particularly relevant to pathogenesis and virulence of C. albicans. IMPORTANCE C. albicans is an important fungal pathogen of humans. The cell wall is the outermost layer of C. albicans and is important for commensalism and infection by this pathogen. Moreover, the cell wall is also an important target for antifungals. Studies of how C. albicans maintains its cell wall integrity are critical for a better understanding of fungal pathogenesis and virulence. This work focuses on exploring unknown functions of C. albicans Rap1 and reveals its contribution to cell wall integrity, biofilm formation, and virulence. Notably, these findings will also improve our general understanding of complex machinery to control pathogenesis and virulence of fungal pathogens.}, } @article {pmid36416468, year = {2022}, author = {Parolina de Carvalho, RD and de Andrade Moreno, J and Roque, SM and Chan, DCH and Torrez, WB and Stipp, RN and Bueno-Silva, B and de Lima, PO and Cogo-Müller, K}, title = {Statins and oral biofilm: Simvastatin as a promising drug to control periodontal dysbiosis.}, journal = {Oral diseases}, volume = {}, number = {}, pages = {}, doi = {10.1111/odi.14446}, pmid = {36416468}, issn = {1601-0825}, support = {2018/20593-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 132813/2018-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 830533/1999-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {OBJECTIVES: This study evaluated antimicrobial activity of atorvastatin, pravastatin, rosuvastatin, and simvastatin against oral bacteria, and the interaction of simvastatin with standard antimicrobials (amoxicillin and metronidazole).

METHODS: Minimal inhibitory concentration assays were performed with Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinomyces odontolyticus, Streptococcus oralis, Streptococcus mitis, Streptococcus salivarius, Streptococcus sanguinis, and Streptococcus gordonii; checkerboard microdilution assays between simvastatin and standard antimicrobials; monospecies and multispecies biofilms.

RESULTS: Simvastatin showed the best antimicrobial activity against most species (MIC range from 3.12 to 25 μg/ml), highlighting the sensitivity of P. gingivalis. In the checkerboard assay, synergistic interaction was found between simvastatin and amoxicillin against S. oralis and S. sanguinis. P. gingivalis biofilm was inhibited by simvastatin at 10 and 50× Minimal inhibitory concentration, with similar effects to metronidazole. For multispecies biofilm, SMV reduced the biofilm metabolic activity (79%) and total counts (87%), comparable to amoxicillin. Simvastatin also reduced bacterial counts of Veilonnella parvula, P. gingivalis, Streptococcus mutans, Actinomyces naeslundii, P. intermedia, and Capnocytophaga ochracea in the multispecies biofilm.

CONCLUSIONS: Simvastatin showed antimicrobial and antibiofilm activity against oral bacteria and may contribute to the control of dysbiosis, and may be considered in clinical studies as an adjuvant in the treatment of periodontitis.}, } @article {pmid36415579, year = {2022}, author = {Kim, NN and Kim, BS and Lee, HB and An, S and Kim, D and Kang, SS}, title = {Effect of Bacteriocin-Like Inhibitory Substance (BLIS) from Enterococcus faecium DB1 on Cariogenic Streptococcus mutans Biofilm Formation.}, journal = {Food science of animal resources}, volume = {42}, number = {6}, pages = {1020-1030}, pmid = {36415579}, issn = {2636-0780}, abstract = {The aim of the study was to investigate the effect of bacteriocin-like inhibitory substance (BLIS) from Enterococcus faecium DB1 on cariogenic Streptococcus mutans biofilm. Crystal violet staining, fluorescence, and scanning electron microscopy analyses demonstrated that the BLIS from Enterococcus faecium DB1 (DB1 BLIS) inhibited S. mutans biofilm. When DB1 BLIS was co-incubated with S. mutans, biofilm formation by S. mutans was significantly reduced (p<0.05). DB1 BLIS also destroyed the preformed biofilm of S. mutans. In addition, DB1 BLIS decreased the viability of S. mutans biofilm cells during the development of biofilm formation and in the preformed biofilm. DB1 BLIS significantly decreased the growth of S. mutans planktonic cells. Furthermore, S. mutans biofilm on the surface of saliva-coated hydroxyapatite discs was reduced by DB1 BLIS. Taken together, DB1 BLIS might be useful as a preventive and therapeutic agent against dental caries caused by S. mutans.}, } @article {pmid36415244, year = {2022}, author = {Salah-Ud-Din, and Awan, AB and Arshad, MM and Haque, A}, title = {Level of biofilm production by Staphylococcus aureus isolates is critical for resistance against most but not all antimicrobial drugs.}, journal = {Pakistan journal of medical sciences}, volume = {38}, number = {8}, pages = {2150-2155}, pmid = {36415244}, issn = {1682-024X}, abstract = {BACKGROUND AND OBJECTIVE: Staphylococcal biofilms cause a wide range of acute and chronic infections, both in hospital and community settings across the world. This study explores biofilm forming propensity among Staphylococcus aureus clinical isolates from Faisalabad, Pakistan and their association with antimicrobial drug resistance.

METHODS: The study was conducted during July to December 2020. The biofilm forming ability of S. aureus isolates was assessed by crystal violet staining in 96 well plates. Antimicrobial susceptibility was determined by disk diffusion method against ten antimicrobials representing whole spectrum of antimicrobial drugs.

RESULTS: All the isolates (n=22) produced biofilm; 14 (63.6%) were strong, and 8 (36.4%) moderate biofilm producers. Comparative data were obtained for moderate and strong biofilm producers. Increased biofilm production did not affect azithromycin, clindamycin and mupirocin. However, stronger biofilm production significantly increased resistant isolates in case of augmentin (23.2%), cefoxitin (17.9%), levofloxacin (26.8%), tetracycline (23.2%), vancomycin (14.3%) and trimethoprim (21.4%).

CONCLUSIONS: Our findings indicate that the ability to produce large amount of biofilm is an important factor, and S. aureus isolates with this ability, do not require acquisition of drug resistance genes from other bacteria. Our study also provides a guideline for selection of antimicrobials which are not adversely affected by level of biofilm production by various strains of S. aureus.}, } @article {pmid36414881, year = {2023}, author = {Graciani, J and Rosalen, PL and de Oliveira Chaves Dos Santos, E and Rocha, KAP and Balen, BRT and Garcia, MAR and Lazarini, JG and da Silva, DR and Carvalho, SG and Regasini, LO and Chorilli, M and Orlandi Sardi, JC}, title = {Evaluation of efficacy of new chalcone-based endodontic irrigant against dual biofilm Enterococcus faecalis and Candida albicans: a study in vitro.}, journal = {Odontology}, volume = {111}, number = {3}, pages = {573-579}, pmid = {36414881}, issn = {1618-1255}, support = {001//CAPES/ ; }, mesh = {Humans ; *Candida albicans ; Enterococcus faecalis ; *Chalcones/pharmacology ; Root Canal Irrigants/pharmacology ; Sodium Hypochlorite/pharmacology ; Biofilms ; Dental Pulp Cavity ; }, abstract = {The aim of this research was to develop a chalcone-based endodontic irrigant for cleaning and disinfecting the root canal. Minimal inhibitory concentration (MIC) experiments in C. albicans and E. faecalis strains with different aminochalcones (AM) were carried out, and the compound that presented the best activity against both pathogens was chosen. The formulation of an endodontic irrigant was elaborated, tested in mono and dual specie biofilms. Disks were sterilized and then incubated with E. faecalis, C. albicans and E. faecalis and C. albicans mixed for 72 h for biofilm maturation. After contamination, samples were divided in 4 experimental groups and 2 positive control group as follows: Group1: Irrigant; Group2: Irrigant + AM-38; Group3: Chlorhexidine 2% (positive control) and, Group 4: 1.0% sodium hypochlorite (positive control). The samples were analyzed by CFU/ml count. The sample was taken to sonicador to remove the cells and then plated. The toxicity was determined in vitro with human gingival fibroblast cells (HGF) and in vivo using the Galleria mellonella model. Formulation showed antimicrobial activity, with MIC on C. albicans 15.6 and E. faecalis 7.8 µg/ml. Treatment with formulation in concentration 156 µg/ml significantly reduced mono or dual species biofilm formation and viability (p < 0.05). The results were significant against C. albicans and E. faecalis and did not show toxicity in cells and G. mellonella. In general, the formulation showed effective antibiofilm activity, significantly reducing microorganisms, opening paths in search of new endodontic irrigants.}, } @article {pmid36414152, year = {2023}, author = {Surur, AK and Momesso, VM and Lopes, PM and Ferrisse, TM and Fontana, CR}, title = {Assessment of synergism between enzyme inhibition of Cu/Zn-SOD and antimicrobial photodynamic therapy in suspension and E. coli biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {41}, number = {}, pages = {103185}, doi = {10.1016/j.pdpdt.2022.103185}, pmid = {36414152}, issn = {1873-1597}, mesh = {*Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Escherichia coli ; Superoxide Dismutase-1 ; Reactive Oxygen Species ; *Anti-Infective Agents ; Superoxide Dismutase ; Zinc ; Biofilms ; }, abstract = {BACKGROUND: Antimicrobial Photodynamic Therapy (aPDT) is a treatment based on the interaction between a photosensitizer (PS), oxygen and a light source, resulting in the production of reactive oxygen species (ROS). There are two main types of reactions that can be triggered by this interaction: type I reaction, which can result in the production of hydrogen peroxide, superoxide anion and hydroxyl radical, and type II reaction, which is the Photodynamic Reaction, which results in singlet oxygen production. Antioxidant enzymes (e.g., catalase and superoxide dismutase) are agents that help prevent the damage caused by ROS and, consequently, reduce the effectiveness of aPDT. The aim of this study was to evaluate a possible synergism of the combined inhibition therapy of the enzyme Cu/Zn-Superoxide dismutase (SOD) and the methylene blue- and curcumin-mediated aPDT against Escherichia coli ATCC 25922, in suspension and biofilm.

METHODS: Kinetic assay of antimicrobial activity of diethydithiocarbamate (DDC) and Minimum Bactericidal Concentration (MIC) of DDC were performed to evaluate the behavior of the compound on bacterial suspension. Inhibition times of Cu/Zn-SOD, as well as DDC concentration, were evaluated via bacterial susceptibility to combined therapy in suspension and biofilm.

RESULTS: DDC did not present MIC at the evaluated concentrations. The inhibition time and Cu/Zn-SOD concentration with the highest bacterial reductions were 30 minutes and 1.2 μg/mL, respectively. Synergism occurred between DDC and MB-mediated aPDT, but not with CUR-mediated aPDT.

CONCLUSIONS: The synergism between Cu/Zn-SOD inhibition and aPDT has been confirmed, opening up a new field of study full of possibilities.}, } @article {pmid36413403, year = {2022}, author = {Sun, R and Yu, P and Zuo, P and Villagrán, D and Mathieu, J and Alvarez, PJJ}, title = {Biofilm Control in Flow-Through Systems Using Polyvalent Phages Delivered by Peptide-Modified M13 Coliphages with Enhanced Polysaccharide Affinity.}, journal = {Environmental science & technology}, volume = {56}, number = {23}, pages = {17177-17187}, doi = {10.1021/acs.est.2c06561}, pmid = {36413403}, issn = {1520-5851}, mesh = {*Bacteriophages/genetics ; Extracellular Polymeric Substance Matrix ; Biofilms ; Pseudomonas aeruginosa ; Coliphages ; Peptides/pharmacology ; Polysaccharides/pharmacology ; Water ; }, abstract = {Eradication of biofilms that may harbor pathogens in water distribution systems is an elusive goal due to limited penetration of residual disinfectants. Here, we explore the use of engineered filamentous coliphage M13 for enhanced biofilm affinity and precise delivery of lytic polyvalent phages (i.e., broad-host-range phages lysing multiple host strains after infection). To promote biofilm attachment, we modified the M13 major coat protein (pVIII) by inserting a peptide sequence with high affinity for Pseudomonas aeruginosa (P. aeruginosa) extracellular polysaccharides (commonly present on the surface of biofilms in natural and engineered systems). Additionally, we engineered the M13 tail fiber protein (pIII) to contain a peptide sequence capable of binding a specific polyvalent lytic phage. The modified M13 had 102- and 5-fold higher affinity for P. aeruginosa-dominated mixed-species biofilms than wildtype M13 and unconjugated polyvalent phage, respectively. When applied to a simulated water distribution system, the resulting phage conjugates achieved targeted phage delivery to the biofilm and were more effective than polyvalent phages alone in reducing live bacterial biomass (84 vs 34%) and biofilm surface coverage (81 vs 22%). Biofilm regrowth was also mitigated as high phage concentrations induced residual bacteria to downregulate genes associated with quorum sensing and extracellular polymeric substance secretion. Overall, we demonstrate that engineered M13 can enable more accurate delivery of polyvalent phages to biofilms in flow-through systems for enhanced biofilm control.}, } @article {pmid36412878, year = {2022}, author = {Vigué, A and Vautier, D and Kaytoue, A and Senger, B and Arntz, Y and Ball, V and Ben Mlouka, A and Gribova, V and Hajjar-Garreau, S and Hardouin, J and Jouenne, T and Lavalle, P and Ploux, L}, title = {Escherichia coli Biofilm Formation, Motion and Protein Patterns on Hyaluronic Acid and Polydimethylsiloxane Depend on Surface Stiffness.}, journal = {Journal of functional biomaterials}, volume = {13}, number = {4}, pages = {}, pmid = {36412878}, issn = {2079-4983}, support = {ERMES project//Region Grand Est/ ; }, abstract = {The surface stiffness of the microenvironment is a mechanical signal regulating biofilm growth without the risks associated with the use of bioactive agents. However, the mechanisms determining the expansion or prevention of biofilm growth on soft and stiff substrates are largely unknown. To answer this question, we used PDMS (polydimethylsiloxane, 9-574 kPa) and HA (hyaluronic acid gels, 44 Pa-2 kPa) differing in their hydration. We showed that the softest HA inhibited Escherichia coli biofilm growth, while the stiffest PDMS activated it. The bacterial mechanical environment significantly regulated the MscS mechanosensitive channel in higher abundance on the least colonized HA-44Pa, while Type-1 pili (FimA) showed regulation in higher abundance on the most colonized PDMS-9kPa. Type-1 pili regulated the free motion (the capacity of bacteria to move far from their initial position) necessary for biofilm growth independent of the substrate surface stiffness. In contrast, the total length travelled by the bacteria (diffusion coefficient) varied positively with the surface stiffness but not with the biofilm growth. The softest, hydrated HA, the least colonized surface, revealed the least diffusive and the least free-moving bacteria. Finally, this shows that customizing the surface elasticity and hydration, together, is an efficient means of affecting the bacteria's mobility and attachment to the surface and thus designing biomedical surfaces to prevent biofilm growth.}, } @article {pmid36412873, year = {2022}, author = {Ionescu, AC and Hahnel, S and Chiari, MDS and König, A and Delvecchio, P and Braga, RR and Zambelli, V and Brambilla, E}, title = {TEGDMA-Functionalized Dicalcium Phosphate Dihydrate Resin-Based Composites Prevent Secondary Caries in an In Vitro Biofilm Model.}, journal = {Journal of functional biomaterials}, volume = {13}, number = {4}, pages = {}, pmid = {36412873}, issn = {2079-4983}, abstract = {This study evaluated the efficacy of experimental TEGDMA-functionalized dicalcium phosphate dihydrate (T-DCPD) filler-based resin-based composites (RBC) in preventing caries lesions around the restoration margins (secondary caries, SC). Standardized Class-II cavities were made in sound molars with the cervical margin in dentin. Cavities were filled with a commercial resin-modified glass-ionomer cement (RMGIC) or experimental RBCs containing a bisGMA-TEGDMA resin blend and one of the following inorganic fractions: 60 wt.% Ba glass (RBC-0); 40 wt.% Ba glass and 20 wt.% T-DCPD (RBC-20); or 20 wt.% Ba glass and 40 wt.% T-DCPD (RBC-40). An open-system bioreactor produced Streptococcus mutans biofilm-driven SC. Specimens were scanned using micro-CT to evaluate demineralization depths. Scanning electron microscopy and energy-dispersive X-ray spectroscopy characterized the specimen surfaces, and antimicrobial activity, buffering effect, and ion uptake by the biofilms were also evaluated. ANOVA and Tukey’s tests were applied at p < 0.05. RBC-0 and RBC-20 showed SC development in dentin, while RBC-40 and RMGIC significantly reduced the lesion depth at the restoration margin (p < 0.0001). Initial enamel demineralization could be observed only around the RBC-0 and RBC-20 restorations. Direct antibiofilm activity can explain SC reduction by RMGIC, whereas a buffering effect on the acidogenicity of biofilm can explain the behavior of RBC-40. Experimental RBC with CaP-releasing functionalized T-DCPD filler could prevent SC with the same efficacy as F-releasing materials.}, } @article {pmid36412864, year = {2022}, author = {Zeng, L and Walker, AR and Calderon, PDS and Xia, X and Ren, F and Esquivel-Upshaw, JF}, title = {The Effect of Amino Sugars on the Composition and Metabolism of a Microcosm Biofilm and the Cariogenic Potential against Teeth and Dental Materials.}, journal = {Journal of functional biomaterials}, volume = {13}, number = {4}, pages = {}, pmid = {36412864}, issn = {2079-4983}, support = {DE012236/DE/NIDCR NIH HHS/United States ; R01-DE025001/DE/NIDCR NIH HHS/United States ; Finance Code 001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {Amino sugars N-acetylglucosamine (GlcNAc) and glucosamine (GlcN) are abundant sources of carbon and nitrogen in the oral cavity. The aim of this study was to investigate the effects of GlcNAc metabolism on the genomics and biochemistry of a saliva-derived microbial community, and on the surface integrity of human teeth and restorative surfaces. Pooled cell-containing saliva (CCS) was used to establish a microcosm biofilm in vitro in a biofilm medium (BM) containing 5 different carbohydrates. The microbial composition of each biofilm was analyzed by 16S rRNA amplicon sequencing, and the concentrations of eight organic acids were determined for selected sugars by targeted metabolomics. Meanwhile, extracted human teeth and polished titanium and ceramic disks were submerged in BM supplemented with 1% of glucose or GlcNAc, inoculated with CCS and Streptococcus mutans UA159, and incubated for 30 days. To mimic the effects of other microbial byproducts, the specimens were immersed in 10 mM hydrogen peroxide and 10 mM ammonium hydroxide for 30 days. The surface of each specimen was evaluated by profilometry for roughness (Ra) and imaged by scanning electron microscopy. The pH of the biofilm supernatant was significantly higher for the medium containing GlcNAc (p < 0.0001), and was higher in samples containing teeth than the two restorative disks for media containing the same sugar. For both teeth and titanium specimens, the samples treated with glucose-biofilm presented higher roughness values (Ra) than those with GlcNAc-biofilm and every other group. SEM images of the teeth and titanium disks largely supported the profilometry results, with glucose-biofilm samples demonstrating the largest deviation from the reference. For ceramic disks, slightly higher Ra values were obtained for the ammonia group. These findings provide the first direct evidence to support the ability of amino sugars to significantly reduce the cariogenic potential of oral biofilms by altering their biochemistry and bacterial composition. Additionally, amino sugar metabolism appears to be less detrimental to teeth and restorative surfaces than glucose metabolism.}, } @article {pmid36411767, year = {2022}, author = {Zhang, Z and Chen, J and Zou, L and Tang, J and Zheng, J and Luo, M and Wang, G and Liang, D and Li, Y and Chen, B and Yan, H and Ding, W}, title = {Preparation, Characterization, and Staphylococcus aureus Biofilm Elimination Effect of Baicalein-Loaded β-Cyclodextrin-Grafted Chitosan Nanoparticles.}, journal = {International journal of nanomedicine}, volume = {17}, number = {}, pages = {5287-5302}, pmid = {36411767}, issn = {1178-2013}, mesh = {*Chitosan/pharmacology ; Staphylococcus aureus ; *Nanoparticles ; *beta-Cyclodextrins ; }, abstract = {BACKGROUND AND PURPOSE: Infections caused by Staphylococcus aureus (S. aureus) colonization in medical implants are resistant to antibiotics due to the formation of bacterial biofilm internal. Baicalein (BA) has been confirmed as an inhibitor of bacterial biofilm with less pronounced effects owing to its poor solubility and absorption. Studies have found that β-cyclodextrin-grafted chitosan (CD-CS) can improve drug efficiency as a drug carrier. Therefore, this research aims to prepare BA-loaded CD-CS nanoparticles (CD-CS-BA-NPs) for S. aureus biofilm elimination enhancement.

METHODS: CD-CS-BA-NPs were prepared via the ultrasonic method. The NPs were characterized using the X-ray diffraction (XRD), Thermo gravimetric analyzer (TGA), Transmission electron microscopy (TEM) and Malvern Instrument. The minimum inhibitory concentration (MIC) of the NPs were investigated. The biofilm models in vivo and in vitro were constructed to assess the S. aureus biofilm elimination ability of the NPs. The Confocal laser method (CLSM) and the Live/Dead kit were employed to explore the mechanism of the NPs in promoting biofilm elimination.

RESULTS: CD-CS-BA-NPs have an average particle size of 424.5 ± 5.16 nm, a PDI of 0.2 ± 0.02, and a Zeta potential of 46.13 ± 1.62 mV. TEM images revealed that the NPs were spherical with uniform distribution. XRD and TGA analysis verified the formation and the thermal stability of the NPs. The NPs with a MIC of 12.5 ug/mL exhibited a better elimination effect on S. aureus biofilm both in vivo and in vitro. The mechanism study demonstrated that the NPs may permeate into the biofilm more easily, thereby improving the biofilm elimination effect of BA.

CONCLUSION: CD-CS-BA-NPs were successfully prepared with enhanced elimination of S. aureus biofilm, which may serve as a reference for future development of anti-biofilm agents.}, } @article {pmid36409142, year = {2022}, author = {Chavignon, M and Coignet, L and Bonhomme, M and Bergot, M and Tristan, A and Verhoeven, P and Josse, J and Laurent, F and Butin, M}, title = {Environmental Persistence of Staphylococcus capitis NRCS-A in Neonatal Intensive Care Units: Role of Biofilm Formation, Desiccation, and Disinfectant Tolerance.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0421522}, pmid = {36409142}, issn = {2165-0497}, mesh = {Adult ; Infant, Newborn ; Humans ; *Staphylococcus capitis ; Anti-Bacterial Agents/therapeutic use ; *Staphylococcal Infections/microbiology ; Intensive Care Units, Neonatal ; *Disinfectants/pharmacology ; Desiccation ; *Sepsis/microbiology ; }, abstract = {The clone Staphylococcus capitis NRCS-A is responsible for late-onset sepsis in neonatal intensive care units (NICUs) worldwide. Over time, this clone has evolved into three subgroups that are increasingly adapted to the NICU environment. This study aimed to decipher the mechanisms involved in NRCS-A persistence in NICUs. Twenty-six S. capitis strains belonging to each of the three NRCS-A clone subgroups and two other non-NRCS-A groups from neonates (alpha clone) or from adult patients ("other strains") were compared based on growth kinetics and ability to form biofilm as well as tolerance to desiccation and to different disinfectants. S. capitis biofilm formation was enhanced in rich medium and decreased under conditions of nutrient stress for all strains. However, under conditions of nutrient stress, NRCS-A strains presented an enhanced ability to adhere and form a thin biofilm containing more viable and culturable bacteria (mean 5.7 log10 CFU) than the strains from alpha clone (mean, 1.1 log10 CFU) and the "other strains" (mean, 4.2 log10 CFU) (P < 0.0001). The biofilm is composed of bacterial aggregates with a matrix mainly composed of polysaccharides. The NRCS-A clone also showed better persistence after a 48-h desiccation. However, disinfectant tolerance was not enhanced in the NRCS-A clone in comparison with that of strains from adult patients. In conclusion, the ability to form biofilm under nutrient stress and to survive desiccation are two major advantages for clone NRCS-A that could explain its ability to persist and settle in the specific environment of NICU settings. IMPORTANCE Neonatal intensive care units (NICUs) host extremely fragile newborns, including preterm neonates. These patients are very susceptible to nosocomial infections, with coagulase-negative staphylococci being the species most frequently involved. In particular, a Staphylococcus capitis clone named NRCS-A has emerged worldwide specifically in NICUs and is responsible for severe nosocomial sepsis in preterm neonates. This clone is specifically adapted to the NICU environment and is able to colonize and maintain on NICU surfaces. The present work explored the mechanisms involved in the persistence of the NRCS-A clone in the NICU environment despite strict hygiene measures. The ability to produce biofilm under nutritional stress and to resist desiccation appear to be the two main advantages of NRCS-A in comparison with other strains. These findings are pivotal to provide clues for subsequent development of targeted methods to combat NRCS-A and to stop its dissemination.}, } @article {pmid36408892, year = {2023}, author = {Ouyang, Q and Zeng, Y and Yu, Y and Tan, L and Liu, X and Zheng, Y and Wu, S}, title = {Ultrasound-Responsive Microneedles Eradicate Deep-Layered Wound Biofilm Based on TiO2 Crystal Phase Engineering.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {19}, number = {3}, pages = {e2205292}, doi = {10.1002/smll.202205292}, pmid = {36408892}, issn = {1613-6829}, mesh = {*Staphylococcus aureus/physiology ; *Nanoparticles/chemistry ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {Wound biofilm infection has an inherent resistance to antibiotics, requiring physical debridement combined with chemical reagents or antibiotics in clinical treatment, but it is invasive and may exist as incomplete debridement. So, a new type of noninvasive and efficient treatment is needed to address this problem. Here, the crystal phase engineering of TiO2 is presented to explore the sonocatalytic properties of TiO2 nanoparticles with different phases, and find that the anatase-brookite TiO2 (AB) has the best antibacterial efficiency of 99.94% against S. aureus under 15 min of ultrasound (US) irradiation. The type II homojunction of AB not only enhances the adsorption and decreases the activation energy of O2 , respectively, but also has a great interfacial charge transfer efficiency under US, which can produce more reactive oxygen species than other types of TiO2 . The microneedles (MN) penetrate the biofilm in wound tissue and quickly disperse the loaded AB into the biofilm because the ultrasonic cavitation accelerates the dissolution of microneedles, which non-invasively and efficiently eradicates the deep-layered biofilm under US. This work explores the relationship between the phase composition of TiO2 and sonocatalytic property for the first time, and provides a new treatment strategy for wound biofilm infection through US-assisted microneedles therapy.}, } @article {pmid36407778, year = {2022}, author = {Hajihassani, N and Alavi, O and Karamshahi, M and Marashi, SMA and Khademi, A and Mohammadi, N}, title = {Antibacterial effect of nano-chlorhexidine on Enterococcus faecalis biofilm in root canal system: An in vitro study.}, journal = {Dental research journal}, volume = {19}, number = {}, pages = {80}, pmid = {36407778}, issn = {1735-3327}, abstract = {BACKGROUND: A new method to improve the properties of the materials is nano-encapsulation, which improves the biological properties, antibacterial activity along with reduction of toxicity. Due to the spread of nano-knowledge, the present study was performed to evaluate the antibacterial effect of nano-chlorhexidine (CHX) on Enterococcus faecalis biofilm in the root canal system.

MATERIALS AND METHODS: In this in vitro experimental study, 55 matured single-root mandibular premolars were decoronated and the canals were prepared by single length method up to #F3 ProTaper Universal system. Five teeth were selected as negative control. Then, the teeth were randomly divided into three experimental groups (n = 15) and a positive control group (n = 5). The experimental groups were irrigated with 2% nano- CHX gel, 2% CHX solution, and 5.25% sodium hypochlorite (NaOCl), respectively. Finally, the number of colonies was counted. Kruskal-Wallis test was used to compare the number of colonies among groups. The level of significance was set at P < 0.05.

RESULTS: The mean number of colonies in the groups of nano-CHX, NaOCl, CHX, and positive control were obtained as 17.73 ± 18.69, 35.53 ± 36.42, 38.8 ± 31.8, and 96.8 ± 22.52, respectively. There was a significant decrease in the number of colonies in all the experimental groups compared to the control group (P < 0.05). However, difference in the number of colonies among these three groups was not significant (P > 0.05).

CONCLUSION: The use of nano-CHX in removing E. faecalis biofilm from root canal is as effective as the use of CHX and NaOCl.}, } @article {pmid36406600, year = {2022}, author = {Abdel-Fattah, HK and El-Seddik, MM and Galal, MM and Mostafa, NG}, title = {A comparative study for hybrid UASB reactor performance using polyethylene media and luffa sponge as biofilm support.}, journal = {Journal of environmental health science & engineering}, volume = {20}, number = {2}, pages = {749-756}, pmid = {36406600}, issn = {2052-336X}, abstract = {This paper study the performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor treating low-strength synthetic wastewater using different biofilm supporting materials. Two identical reactors are constructed and operated at constant up-flow velocity of 0.1 m/hr., inflow rate of 9.76 L/d, and hydraulic retention time (HRT) of 8.26 hours. The Start-up phase, using seed sludge for existing wastewater treatment plant, lasted until the efficiency of chemical oxygen demand (COD) removal of both reactors reached 80%. Polyethylene (PE) media are added to one of the reactors and luffa sponge is used in the second reactor. Results show increased COD removal efficiency up to about 90% at 20 °C and biogas production rates from 3.8*10[-3] till 7.5*10[-3] m[3] CH4/kg CODr using PE media. The COD removal efficiency reaches about 95% at 20 °C using luffa sponge and biogas production rates up to 6.5*10 [-3] m[3] CH4/kg CODr are achieved before clogging problem is observed. Effect of HRT reduction, from 8.26 to 4.13 hours, on removing clogging is investigated. Reduction in COD removal efficiencies is observed at low ambient temperatures during seasonal variations of 15-25 °C. AFM and SEM analysis are used to examine sludge granulation and biofilm formation.}, } @article {pmid36406439, year = {2022}, author = {Idir, F and Van Ginneken, S and Coppola, GA and Grenier, D and Steenackers, HP and Bendali, F}, title = {Origanum vulgare ethanolic extracts as a promising source of compounds with antimicrobial, anti-biofilm, and anti-virulence activity against dental plaque bacteria.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {999839}, pmid = {36406439}, issn = {1664-302X}, abstract = {Dental caries and periodontal diseases remain a challenge for oral health, especially given the lack of effective and safe treatment options that are currently available. Against the backdrop of an ongoing antimicrobial resistance crisis, a renewed interest in traditional medicinal plants as a potential source of new bioactive compounds has surfaced. In this context, we systematically screened the antimicrobial and anti-biofilm activities of both ethanolic and aqueous extracts of nine Algerian medicinal plants (Artemisia herba alba, Centaurium erythraea, Juglans regia, Laurus nobilis, Matricaria recutita, Mentha pulegium, Mentha piperita, Origanum vulgare and Taraxacum officinale). To evaluate the activity spectrum of the extracts, the screening was carried out against an extensive collection of Streptococcus, Enterococcus and Lacticaseibacillus isolates recovered from dental plaques of Algerian patients. Broad-spectrum antimicrobial and anti-biofilm properties were observed, especially among ethanolic extracts, which marks them as a promising source for bioactive compounds to control oral biofilms. The ethanolic extract of O. vulgare, which showed the most promising effects in the initial screening, was further characterized. We first verified the biocompatibility of this extract using human oral keratinocytes and selected a range of non-cytotoxic concentrations (0.195-0.781 mg/ml) to further validate its anti-biofilm and anti-virulence potential. At these concentrations, the extract not only prevented biofilm formation (10.04 ± 0.75-87.91 ± 9.08% of reduction) of most dental plaque isolates on a polystyrene surface, but also significantly reduced their adherence to hydroxyapatite (34.58 ± 9.09-62.77 ± 0.95%). Moreover, the extract showed curative potential against mature biofilms grown under conditions mimicking the oral niche. In addition to its anti-biofilm properties, we observed an inhibition of glucosyltransferase activity, a reduction in acidogenesis and a downregulation in the expression of multiple virulence-associated genes for extract-treated samples. Since anti-virulence properties are more robust to the development of resistance, they provide an attractive complementation to the antimicrobial activities of the extract. Thymol was identified as an important active compound of the extract using GC-MS analysis, but synergy with other compounds was also detected, suggesting a potential advantage of using the whole extract over purified thymol. Further research into the bioactive compounds of the O. vulgare ethanolic extract could yield novel products to fight dental caries.}, } @article {pmid36405963, year = {2022}, author = {Wang, J and Rao, L and Huang, Z and Ma, L and Yang, T and Yu, Z and Sun, A and Ge, Y}, title = {The nitric oxide synthase gene negatively regulates biofilm formation in Staphylococcus epidermidis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1015859}, pmid = {36405963}, issn = {2235-2988}, mesh = {*Staphylococcus epidermidis ; Phylogeny ; *Iron-Dextran Complex/pharmacology ; Biofilms ; Nitric Oxide Synthase ; }, abstract = {Staphylococcus epidermidis (S. epidermidis) is a clinically important conditioned pathogen that can cause a troublesome chronic implant-related infection once a biofilm is formed. The nitric oxide synthase (NOS) gene, which is responsible for endogenous nitric oxide synthesis, has already been found in the genome of S. epidermidis; however, the specific mechanisms associated with the effects of NOS on S. epidermidis pathogenicity are still unknown. The purpose of the current study was to investigate whether the NOS gene has an impact on biofilm formation in S. epidermidis. Bioinformatics analysis of the NOS gene was performed, and homologous recombination was subsequently employed to delete this gene. The effects of the NOS gene on biofilm formation of S. epidermidis and its underlying mechanisms were analyzed by bacterial growth assays, biofilm semiquantitative determination, Triton X-100-induced autolysis assays, and bacterial biofilm dispersal assays. Additionally, the transcription levels of fbe, aap, icaA, icaR and sigB, which are related to biofilm formation, were further investigated by qRT-PCR following NOS deletion. Phylogenetic analysis revealed that the NOS gene was conserved between bacterial species originating from different genera. The NOS deletion strain of S. epidermidis 1457 and its counterpart were successfully constructed. Disruption of the NOS gene resulted in significantly enhanced biofilm formation, slightly retarded bacterial growth, a markedly decreased autolysis rate, and drastically weakened bacterial biofilm dispersal. Our data showed that the fbe, aap and icaA genes were significantly upregulated, while the icaR and sigB genes were significantly downregulated, compared with the wild strain. Therefore, these data strongly suggested that the NOS gene can negatively regulate biofilm formation in S. epidermidis by affecting biofilm aggregation and dispersal.}, } @article {pmid36403927, year = {2022}, author = {Zheng, N and Zhou, M and He, Y and Xu, H and Chen, X and Duan, Z and Yang, L and Zeng, R and Liu, Y and Li, M}, title = {Low curcumin concentrations combined with blue light inhibits cutibacterium acnes biofilm-induced inflammatory response through suppressing MAPK and NF-κB in keratinocytes.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103204}, doi = {10.1016/j.pdpdt.2022.103204}, pmid = {36403927}, issn = {1873-1597}, mesh = {Humans ; NF-kappa B/metabolism ; *Curcumin/pharmacology ; *Photochemotherapy/methods ; Propionibacterium acnes/metabolism ; Keratinocytes/metabolism ; Inflammation ; }, abstract = {BACKGROUND: Curcumin has been employed as a photosensitizer agent during photodynamic therapy (PDT). Cutibacterium acnes (C. acnes) can cause an inflammatory response in human keratinocytes; however, no research has been conducted to determine whether curcumin and its photodynamic properties can prevent this inflammatory reaction.

OBJECTIVE: We hypothesized that curcumin may control the C. acnes biofilm-induced inflammatory response in keratinocytes, either alone or in combination with blue light photodynamic therapy.

METHODS: Following C. acnes biofilm stimulation, human primary keratinocytes were treated with 20 μM curcumin solution alone or 5 μM curcumin with combined blue light irradiation. The amount of secreted protein was measured using an ELISA kit. The expression levels of Toll-like receptor 2 (TLR2) and its downstream proteins were determined using western blot.

RESULTS: Treatment with 20 μM curcumin, but not 5 μM curcumin, reduced the inflammatory response to C. acnes biofilms in keratinocytes by blocking the TLR2/MAPK/NF-κB pathway. Interestingly, 5 μM curcumin combined with blue light also reduced the C. acnes biofilm-induced inflammation indicated above by blocking the TLR2/MAPK/NF-κB pathway.

CONCLUSION: Curcumin alone, in sufficient concentrations, or low-concentration curcumin with blue light had anti-inflammatory activity on keratinocytes stimulated by C. acnes biofilms through inhibition of MAPK and NF-κB signaling pathways by downregulating TLR2 expression.}, } @article {pmid36402866, year = {2022}, author = {Ramezanalizadeh, F and Rasooli, I and Owlia, P and Darvish Alipour Astaneh, S and Abdolhamidi, R}, title = {Vaccination with a combination of planktonic and biofilm virulence factors confers protection against carbapenem-resistant Acinetobacter baumannii strains.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {19909}, pmid = {36402866}, issn = {2045-2322}, mesh = {Mice ; Animals ; *Acinetobacter baumannii/genetics ; Plankton ; Virulence Factors ; Biofilms ; Vaccination ; Carbapenems/pharmacology ; Vaccines, Combined ; }, abstract = {Acinetobacter baumannii is a multi-drug resistant pathogen with the ability to switch between planktonic and biofilm phenotypes. Although there is no vaccine against A. baumannii infections, many attempts have been made to develop vaccines using planktonic or biofilm antigens. To cover the different phenotypes of A. baumannii during growth and attachment, we combined planktonic upregulated antigens of iron receptors with biofilm upregulated antigens of pilus rods and evaluated immune responses and protective efficacies of the combined vaccine using lethal and sub-lethal murine sepsis models. The results showed that the combined vaccine elicited high IgG antibody titers and conferred protection against lethal doses of two Carbapenem-resistant high adherent A. baumannii strains. Complete bacterial clearance from all the affected tissues of the mice challenged with A. baumannii was an excellent achievement with our quadrivalent immunogen. These results demonstrate both planktonic and biofilm antigens are important during antigen selection for vaccine design.}, } @article {pmid36402858, year = {2022}, author = {Bajrami, D and Fischer, S and Barth, H and Sarquis, MA and Ladero, VM and Fernández, M and Sportelli, MC and Cioffi, N and Kranz, C and Mizaikoff, B}, title = {In situ monitoring of Lentilactobacillus parabuchneri biofilm formation via real-time infrared spectroscopy.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {92}, pmid = {36402858}, issn = {2055-5008}, mesh = {*Extracellular Polymeric Substance Matrix ; *Lactobacillus ; Biofilms ; Stainless Steel ; }, abstract = {Foodborne pathogenic microorganisms form biofilms at abiotic surfaces, which is a particular challenge in food processing industries. The complexity of biofilm formation requires a fundamental understanding on the involved molecular mechanisms, which may then lead to efficient prevention strategies. In the present study, biogenic amine producing bacteria, i.e., Lentilactobacillus parabuchneri DSM 5987 strain isolated from cheese were studied in respect with biofilm formation, which is of substantial relevance given their contribution to the presence of histamine in dairy products. While scanning electron microscopy was used to investigate biofilm adhesion at stainless steel surfaces, in situ infrared attenuated total reflection spectroscopy (IR-ATR) using a custom flow-through assembly was used for real-time and non-destructive observations of biofilm formation during a period of several days. The spectral window of 1700-600 cm[-1] provides access to vibrational signatures characteristic for identifying and tracking L. parabuchneri biofilm formation and maturation. Especially, the amide I and II bands, lactic acid produced as the biofilm matures, and a pronounced increase of bands characteristic for extracellular polymeric substances (EPS) provide molecular insight into biofilm formation, maturation, and changes in biofilm architecture. Finally, multivariate data evaluation strategies were applied facilitating the unambiguous classification of the observed biofilm changes via IR spectroscopic data.}, } @article {pmid36402321, year = {2023}, author = {Verdú, I and Amariei, G and Rueda-Varela, C and González-Pleiter, M and Leganés, F and Rosal, R and Fernández-Piñas, F}, title = {Biofilm formation strongly influences the vector transport of triclosan-loaded polyethylene microplastics.}, journal = {The Science of the total environment}, volume = {859}, number = {Pt 1}, pages = {160231}, doi = {10.1016/j.scitotenv.2022.160231}, pmid = {36402321}, issn = {1879-1026}, mesh = {Microplastics/toxicity ; Plastics/toxicity ; Polyethylene ; *Triclosan/toxicity/analysis ; *Water Pollutants, Chemical/toxicity/analysis ; *Environmental Pollutants/analysis ; }, abstract = {This study aimed at evaluating the influence of biofilm in the role of microplastics (MPs) as vectors of pollutants and their impact on Daphnia magna. To do this, virgin polyethylene MPs, (PE-MPs, 40-48 μm) were exposed for four weeks to wastewater (WW) from influent and effluent to promote biofouling. Then, the exposed PE-MPs were put in contact with triclosan. Finally, the toxicity of TCS-loaded and non-TCS loaded PE-MPs were tested on the survival of D. magna adults for 21 days. Results from metabarcoding analyses indicated that exposure to TCS induced shifts in the bacterial community, selecting potential TCS-degrading bacteria. Results also showed that PE-MPs were ingested by daphnids. The most toxic virgin PE-MPs were those biofouled in the WW effluent. The toxicity of TCS-loaded PE-MPs biofouled in the WW effluent was even higher, reporting mortality in all tested concentrations. These results indicate that biofouling of MPs may modulate the adsorption and subsequent desorption of co-occurring pollutants, hence affecting their potential toxicity towards aquatic organisms. Future studies on realistic environmental plastic impact should include the characterization of biofilms growing on plastic. Since inevitably plastic biofouling occurs over time in nature, it should be taken into account as it may modulate the sorption of co-occurring pollutants.}, } @article {pmid36401726, year = {2023}, author = {Kantiwal, U and Pandey, J}, title = {Efficient Inhibition of Bacterial Biofilm Through Interference of Protein-Protein Interaction of Master Regulator Proteins: a Proof of Concept Study with SinR- SinI Complex of Bacillus subtilis.}, journal = {Applied biochemistry and biotechnology}, volume = {195}, number = {3}, pages = {1947-1967}, pmid = {36401726}, issn = {1559-0291}, support = {SERB/YS/LS/294/2013//Science and Engineering Research Board, Department of Science and Technology- Government of India/ ; }, mesh = {*Bacterial Proteins/chemistry ; *Bacillus subtilis/metabolism ; Proof of Concept Study ; Cefoperazone/metabolism ; Itraconazole/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; }, abstract = {Biofilm-associated microbial growth is a major cause of environmental, industrial, and public health concern. Therefore, there is a pressing need to discover and develop efficient antibiofilm strategies. Regulatory proteins vital for biofilm formation might be ideal targets for developing novel antibiofilm therapeutics. Their activities often depend on protein-protein interactions. Therefore, such targets present unique opportunities and challenges to drug discovery. In Bacillus subtilis, a model organism for studying biofilms, SinR acts as the master regulator of the biofilm formation cascade. Under favourable growth conditions, it represses the epsA-O and tapA-sipW-tasA operons, which encode for essential structural components of biofilms. Under unfavourable growth conditions, SinI, an agonist protein, inactivates SinR by forming a heterotrimeric complex. This results in derepression of epsA-O and tapA-sipW-tasA operons and leads to the phenotypic switch from planktonic to biofilm-associated form. We hypothesized that inhibiting SinR-SinI interaction might warrant repression of epsA-O and tapA-sipW-tasA operons and inhibit biofilm formation. To evaluate this hypothesis, we carried out a drug repurposing study for identifying potential inhibitors of SinI. Cefoperazone and itraconazole were identified as potential inhibitors with virtual screening. The stability of their interaction with SinI was assessed in extended MD performed over 100 ns. Both cefoperazone and itraconazole showed stable interaction. In in vitro studies, cefoperazone hindered the interaction of purified recombinant SinI and SinR. In the whole cell-based biofilm inhibition assays also cefoperazone was found to efficiently inhibited biofilm formation. These results provide proof of concept for targeting protein-protein interaction of master regulators as potential target for discovery and development of antibiofilm therapeutics. We propose that similar drug repurposing studies targeting key regulators of biofilm formation cascade could be an efficient approach for discovering novel anti-biofilm therapeutics against priority pathogens.}, } @article {pmid36401137, year = {2022}, author = {Zhou, G and Wang, YS and Peng, H and Liu, HZ and Feng, J and Li, SJ and Sun, TL and Li, CL and Shi, QS and Xie, XB}, title = {Outer membrane protein of OmpF contributes to swimming motility, biofilm formation, osmotic response as well as the transcription of maltose metabolic genes in Citrobacter werkmanii.}, journal = {World journal of microbiology & biotechnology}, volume = {39}, number = {1}, pages = {15}, pmid = {36401137}, issn = {1573-0972}, support = {31770091//National Natural Science Foundation of China/ ; }, mesh = {*Maltose ; *Swimming ; Osmoregulation ; Bacterial Outer Membrane Proteins/genetics ; Biofilms ; }, abstract = {Bacterial outer membrane proteins (Omps) are essential for environmental sensing, stress responses, and substance transport. Our previous study discovered that OmpA contributes to planktonic growth, biocide resistance, biofilm formation, and swimming motility in Citrobacter werkmanii, whereas the molecular functions of OmpF in this strain are largely unknown. Thus, in this study, the ompF gene was firstly knocked out from the genome of C. werkmanii using a homologous recombination method, and its phenotypical alternations of ∆ompF were then thoroughly characterized using biochemical and molecular approaches with the parental wild type (WT) and complementary (∆ompF-com) strains. The results demonstrated that the swimming ability of ∆ompF on semi-solid plates was reduced compared to WT due to the down-regulation of flgC, flgH, fliK, and fliF. Meanwhile, ompF deletion reduces biofilm formation on both glass and polystyrene surfaces due to decreased cell aggregation. Furthermore, ompF inactivation induced different osmotic stress (carbon sources and metal ions) responses in its biofilms when compared to WT and ∆ompF-com. Finally, a total of 6 maltose metabolic genes of lamB, malE, malK, malG, malM, and malF were all up-regulated in ∆ompF. The gene knockout and HPLC results revealed that the MalEFGK2 cluster was primarily responsible for maltose transport in C. werkmanii. Furthermore, we discovered for the first time that the upstream promoter of OmpF and its transcription can be combined with and negatively regulated by MalT. Overall, OmpF plays a role in a variety of biochemical processes and molecular functions in C. werkmanii, and it may even act as a targeted site to inhibit biofilm formation.}, } @article {pmid36400974, year = {2022}, author = {Li, J and Ning, C and Li, N and Guo, Y and Ji, C and Zhu, X and Zhang, X and Meng, Q and Xia, X and Cai, X and Qiao, J}, title = {The small RNA STnc1480 contributes to the regulation of biofilm formation and pathogenicity in Salmonella typhimurium.}, journal = {Archives of microbiology}, volume = {204}, number = {12}, pages = {716}, pmid = {36400974}, issn = {1432-072X}, support = {No. 2016YFD0500900//national key research and development program/ ; No. 2016YFD0500900//national key research and development program/ ; No. 2016YFD0500900//national key research and development program/ ; No. 2016YFD0500900//national key research and development program/ ; No. 2016YFD0500900//national key research and development program/ ; 2016BC001//Youth Science and Technology Innovation Leader of Xinjiang Production and Construction Corps/ ; 2016BC001//Youth Science and Technology Innovation Leader of Xinjiang Production and Construction Corps/ ; 2016BC001//Youth Science and Technology Innovation Leader of Xinjiang Production and Construction Corps/ ; 2016BC001//Youth Science and Technology Innovation Leader of Xinjiang Production and Construction Corps/ ; 2016BC001//Youth Science and Technology Innovation Leader of Xinjiang Production and Construction Corps/ ; 2019GG026//the Key Scientific and Technological Project in Agriculture of Xinjiang Production and Construction Corps/ ; 2019GG026//the Key Scientific and Technological Project in Agriculture of Xinjiang Production and Construction Corps/ ; 2019GG026//the Key Scientific and Technological Project in Agriculture of Xinjiang Production and Construction Corps/ ; 2019GG026//the Key Scientific and Technological Project in Agriculture of Xinjiang Production and Construction Corps/ ; 2019GG026//the Key Scientific and Technological Project in Agriculture of Xinjiang Production and Construction Corps/ ; }, mesh = {Humans ; Mice ; Animals ; *Salmonella typhimurium/metabolism ; Virulence/genetics ; *RNA ; Gene Expression Regulation, Bacterial ; Bacterial Proteins/genetics/metabolism ; Biofilms ; RNA, Messenger/metabolism ; }, abstract = {Salmonella Typhimurium (STM) is one of the most important food-borne bacteria that seriously harms livestock and human beings, which is capable of regulating the expression of its own genes in a variety of ways to adapt to a wide variety of adverse environmental stresses. To understand the regulatory roles of sRNA STnc1480 on the capability of STM, the STnc1480 gene-deficient strain △STnc1480 and its complement strain △STnc1480/STnc1480 were generated, and the impacts of STnc1480 gene deficiency on the capability of responding to different environmental stresses, biofilm(BF)formation and pathogenicity were analyzed, respectively. Then the target genes that were regulated by STnc1480 were also analyzed and explored. Compared with parent and complement strains, the deficiency of the STnc1480 gene significantly reduced the BF formation. Moreover, the capacities of adhesion and invasiveness of the △STnc1480 strain to macrophages were also significantly reduced, while the LD50 in mice was significantly increased. The bacterial loads in liver and spleen were significantly reduced, and the pathological damage was alleviated. It was confirmed that the STnc1480 could be complementary to the 5'-UTR (-52 to -71 bases) region of lpfA mRNA. The bacterial dual-plasmid reporting system confirmed that STnc1480 was capable of interacting with the mRNA of the lpfA gene, suggesting that STnc1480 can regulate the 5'-UTR of the lpfA mRNA at post-transcription level to reduce the expression of the bacterial fimbria, thus reducing the BF formation and pathogenicity of STM.}, } @article {pmid36400832, year = {2022}, author = {El-Naggar, NE and Shiha, AM and Mahrous, H and Mohammed, ABA}, title = {Green synthesis of chitosan nanoparticles, optimization, characterization and antibacterial efficacy against multi drug resistant biofilm-forming Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {19869}, pmid = {36400832}, issn = {2045-2322}, mesh = {*Chitosan/pharmacology/chemistry ; *Acinetobacter baumannii ; *Nanoparticles/chemistry ; Anti-Bacterial Agents/pharmacology/chemistry ; Biofilms ; }, abstract = {Chitosan nanoparticles (CNPs) are promising versatile cationic polymeric nanoparticles, which have received growing interest over last few decades. The biocompatibility, biodegradability, environmental safety and non-toxicity of the chitosan nanoparticles makes it preferred for a wide range of biological applications including agriculture, medical and pharmaceutical fields. In this study, CNPs were biosynthesized by aqueous extract of Eucalyptus globulus Labill fresh leaves as bio-reductant. Box-Behnken design in 29 experimental runs was used for optimization of different factors affecting the production of CNPs. The maximum yield of CNPs was 9.91 mg/mL at pH of 4.5, chitosan concentration of 1%, incubation time of 60 min and temperature of 50 °C. The crystallinity, particle size and morphology of the biosynthesized CNPs were characterized. The CNPs possess a positively charged surface of 31.1 mV. The SEM images of the CNPs confirms the formation of spherical form with smooth surface. The TEM images show CNPs were spherical in shape and their size range was between 6.92 and 10.10 nm. X-ray diffraction indicates the high degree of CNPs crystallinity. FTIR analysis revealed various functional groups of organic compounds including NH, NH2, C-H, C-O, C-N, O-H, C-C, C-OH and C-O-C. The thermogravimetric analysis results revealed that CNPs are thermally stable. The antibacterial activity of CNPs was determined against pathogenic multidrug-resistant bacteria, Acinetobacter baumannii. The diameters of the inhibition zones were 12, 16 and 30 mm using the concentrations of 12.5, 25 and 50 mg/mL; respectively. When compared to previous studies, the biosynthesized CNPs produced using an aqueous extract of fresh Eucalyptus globulus Labill leaves have the smallest particle sizes (with a size range between 6.92 and 10.10 nm). Consequently, it is a promising candidate for a diverse range of medical applications and pharmaceutical industries.}, } @article {pmid36400647, year = {2023}, author = {Medis, S and Dissanayake, T and Kottahachchi, J and Namali, D and Gunasekara, S and Wijesinghe, G and Dilrukshi, N and Weerasekera, M}, title = {Biofilm formation and antibiotic resistance among Coagulase Negative Staphylococcus species isolated from central venous catheters of intensive care unit patients.}, journal = {Indian journal of medical microbiology}, volume = {42}, number = {}, pages = {71-76}, doi = {10.1016/j.ijmmb.2022.10.007}, pmid = {36400647}, issn = {1998-3646}, mesh = {Humans ; *Central Venous Catheters/adverse effects ; Coagulase ; Gentian Violet ; *Catheter-Related Infections/microbiology ; Staphylococcus ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Drug Resistance, Microbial ; Intensive Care Units ; Cloxacillin ; Biofilms ; }, abstract = {PURPOSE: This study was conducted to determine the biofilm formation of coagulase negative Staphylococcus species (CoNS) isolated from patients with catheter related blood stream infection (CRBSI) and colonized central venous catheters (CVC) and their antibiotic susceptibility patterns and in situ biofilm formation of CVC tips.

METHODS: Eighty-two CoNS isolated from intensive care unit (ICU) patients with CRBSI (n ​= ​8) or colonized CVC (n ​= ​74) were included. Species identification and antibiotic susceptibility test were done. All isolates were screened for biofilm formation using crystal violet and 3-(4,5-dimethylthiazole-2-yl)-2-5-diphenyl-2H-tetrazolium bromide (MTT) assays and categorized as strong or moderate biofilm formers. CVC tips were subjected to crystal violet stain and scanning electron microscopy (SEM) to detect in-situ biofilm formation.

RESULTS: Staphylococcus haemolyticus (n ​= ​34; 41%) was the commonest to cause both CRBSI and CVC colonization. All 82 CoNS produced biofilms. Among them 77 (93.90%) were strong biofilm formers including all from CRBSI patients and 05 (6.10%) were moderate biofilm formers as detected by both methods. SEM showed bacteria adhered to surfaces of CVC tips with microbial-aggregates embedded in extracellular matrix. Mean crystal violet absorbance of CVC from CRBSI patients (0.6628) was significantly higher than colonized CVC (mean value 0.5592) (p ​= ​0.030). S. haemolyticus showed higher resistance to cloxacillin compared to other CoNS (p ​= ​0.039).

CONCLUSION: Majority of CoNS isolated were strong biofilm formers. In-situ biofilm formation on CVC tips were significantly evident in CRBSI patients compared to CVC colonized patients. S. haemolyticus is the commonest to cause both CRBSI and CVC colonization and shows significantly higher cloxacillin resistance rate.}, } @article {pmid36399746, year = {2022}, author = {Sinclair, P and Brackley, CA and Carballo-Pacheco, M and Allen, RJ}, title = {Model for Quorum-Sensing Mediated Stochastic Biofilm Nucleation.}, journal = {Physical review letters}, volume = {129}, number = {19}, pages = {198102}, doi = {10.1103/PhysRevLett.129.198102}, pmid = {36399746}, issn = {1079-7114}, mesh = {*Quorum Sensing ; *Biofilms ; Bacteria ; }, abstract = {Surface-attached bacterial biofilms cause disease and industrial biofouling, as well as being widespread in the natural environment. Density-dependent quorum sensing is one of the mechanisms implicated in biofilm initiation. Here we present and analyze a model for quorum-sensing triggered biofilm initiation. In our model, individual, planktonic bacteria adhere to a surface, proliferate, and undergo a collective transition to a biofilm phenotype. This model predicts a stochastic transition between a loosely attached, finite layer of bacteria near the surface and a growing biofilm. The transition is governed by two key parameters: the collective transition density relative to the carrying capacity and the immigration rate relative to the detachment rate. Biofilm initiation is complex, but our model suggests that stochastic nucleation phenomena may be relevant.}, } @article {pmid36398687, year = {2022}, author = {Xu, W and Ceylan Koydemir, H}, title = {Non-invasive biomedical sensors for early detection and monitoring of bacterial biofilm growth at the point of care.}, journal = {Lab on a chip}, volume = {22}, number = {24}, pages = {4758-4773}, doi = {10.1039/d2lc00776b}, pmid = {36398687}, issn = {1473-0189}, mesh = {Humans ; *Point-of-Care Systems ; }, abstract = {Bacterial infections have long been a serious global health issue. Biofilm formation complicates matters even more. The biofilm's extracellular polymeric substances (EPSs) matrix protects bacteria from the host's immune responses, yielding strong adhesion and drug resistance as the biofilm matures. Early bacterial biofilm detection and bacterial biofilm growth monitoring are crucial to treating biofilm-associated infections. Current detection methods are highly sensitive but not portable, are time-consuming, and require expensive equipment and complex operating procedures, limiting their use at the point of care. Therefore, there is an urgent need to develop affordable, on-body, and non-invasive biomedical sensors to continuously monitor and detect early biofilm growth at the point of care through personalized telemedicine. Herein, recent advances in developing non-invasive biomedical sensors for early detection and monitoring bacterial biofilm growth are comprehensively reviewed. First, biofilm's life cycle and its impact on the human body, such as biofilm-associated disease and infected medical devices, are introduced together with the challenges of biofilm treatment. Then, the current methods used in clinical and laboratory settings for biofilm detection and their challenges are discussed. Next, the current state of non-invasive sensors for direct and indirect detection of bacterial biofilms are summarized and highlighted with the detection parameters and their design details. Finally, commercially available products, challenges of current devices, and the further trend in biofilm detection sensors are discussed.}, } @article {pmid36398568, year = {2023}, author = {Sanghavi, AD and Chopra, A and Shah, A and Lobo, R and Shenoy, PA}, title = {Antimicrobial, anti-adhesion, anti-biofilm properties of goji berry (Lycium barbarum) against periodontal bacteria: potential benefits for periodontal diseases.}, journal = {Journal of complementary & integrative medicine}, volume = {20}, number = {1}, pages = {129-136}, pmid = {36398568}, issn = {1553-3840}, mesh = {*Lycium ; Chlorhexidine/pharmacology ; Doxycycline ; *Periodontal Diseases/drug therapy/microbiology ; *Anti-Infective Agents ; Porphyromonas gingivalis ; }, abstract = {OBJECTIVES: Lycium barbarum, commonly known as goji berry, Himalayan berry, or Tibetian berry, is emerging as a popular "superfood" with anti-inflammatory and antioxidant properties. However, its use for the management of oral inflammatory diseases has not been explored. The present study aims to evaluate the antimicrobial, anti-adhesion, anti-biofilm, and cytotoxic properties of an ethanolic extract of L. barbarum (LBE) against common oral and periodontal pathogens.

METHODS: The antimicrobial properties of LBE against five potential periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Tanerella forsythia) were tested and compared to chlorhexidine and doxycycline using serial dilution and disc diffusion assay. The MTT Assay was performed for evaluating the cytotoxicity and cell viability of the LBE on the gingival fibroblast and modified keratinocyte cell lines. The anti-adhesion and anti-biofilm properties of LBE against P. gingivalis at its minimal bactericidal value were also assessed.

RESULTS: LBE inhibited the growth of periodontal pathogens as compared to control, however, the zone of inhibition of LBE was less when compared to doxycycline and chlorhexidine. The de novo extract showed a maximum zone of inhibition against Tf and Aa. The LBE extract was also compatible to gingival fibroblast tissues and oral keratinocytes at 1 mg/mL.

CONCLUSIONS: L. barbarum is a promising alternative to Chlorhexidine for the management of oral and periodontal infections.}, } @article {pmid36398027, year = {2023}, author = {Radithia, D and Tanjungsari, R and Ernawati, DS and Parmadiati, AE}, title = {The effectiveness of essential oil from Citrus limon peel on Candida albicans biofilm formation: An experimental in vivo study.}, journal = {Journal of Taibah University Medical Sciences}, volume = {18}, number = {1}, pages = {190-195}, pmid = {36398027}, issn = {1658-3612}, abstract = {OBJECTIVES: Candida albicans is resistant to commercial antifungal agents. Therefore, it is desirable to use material derived from natural sources as an antifungal agent. Essential oil from Citrus limon peel is able to inhibit the growth of C. albicans in vitro. The purpose of this study was to determine the most effective concentration of essential oil from C. limon peel with regards to the inhibition of C. albicans cyto-morphometric changes and biofilm formation in vivo.

METHODS: Male Wistar rats weighing 200-300 g were inoculated with C. albicans for 48 h and then given a single dose of oral methylprednisolone as an immunosuppressant. Essential oil from C. limon peel, in a gel form and at three different concentrations (0.39%, 0.78% and 1.56%), was applied twice a day for 2 days. The rats were killed after 48 h and then palatal mucosa tissues were prepared and examined with a scanning electron microscope (SEM) with regards to C. albicans, cyto-morphometric changes and biofilm formation.

RESULTS: Essential oil from C. limon peel at a concentration of 1.56% showed the strongest ability to inhibit C. albicans growth when compared to 0.78% and 0.39%. At a concentration of 1.56%, essential oil from C. limon peel disrupted cyto-morphometric changes; cells that were neither in intact nor colonised were evident, the filaments around the cells were smooth, the layer of biofilm had disappeared and there was no evidence of hyphae formation.

CONCLUSION: The effect of essential oil from C. limon peel on cyto-morphometric changes and biofilm formation was concentration-dependent. Essential oil from C. limon peel at a dose of 1.56% showed the strongest ability to inhibit cyto-morphometric changes and biofilm formation. These findings demonstrate that essential oil of C. limon peel is a potential antifungal candidate for the treatment of candidiasis.}, } @article {pmid36397302, year = {2023}, author = {Pan, M and Li, H and Han, X and Quan, G and Ma, W and Guo, Q and Li, X and Yang, B and Ding, C and Chen, Y and Yun, T and Qin, J and Jiang, S}, title = {Effect of hydrodynamics on the transformation of nitrogen in river water by regulating the mass transfer performance of dissolved oxygen in biofilm.}, journal = {Chemosphere}, volume = {312}, number = {Pt 1}, pages = {137013}, doi = {10.1016/j.chemosphere.2022.137013}, pmid = {36397302}, issn = {1879-1298}, mesh = {*Nitrogen/chemistry ; *Denitrification ; Waste Disposal, Fluid ; Bioreactors ; Oxygen ; Hydrodynamics ; Rivers ; Ecosystem ; Nitrification ; Biofilms ; Water ; Wastewater ; }, abstract = {Biofilms drive crucial ecosystem processes in rivers. This study provided the basis for overall quantitative calculations about the contribution of biofilms to the nitrogen cycle. At the early stage of biofilm formation, dissolved oxygen (DO) could penetrate the biofilms. As the biofilm grew and the thickness increased, then the mass transfer of DO was restricted. The microaerobic layer firstly appeared in biofilm under the turbulent flow conditions, with the appearance of the microaerobic and anaerobic layer, the nitrification and denitrification reaction could proceed smoothly in biofilm. And the removal efficiency of total nitrogen (TN) increased as the biofilm matured. Under the turbulent flow conditions, mature biofilms had the smallest thickness, but the highest proportion the anaerobic layer to the biofilm thickness, the highest density, and the highest nitrogen removal efficiency. However, the nitrogen removal efficiency of biofilm was the lowest under laminar flow conditions. The difference of layered structure of biofilm and the DO flux in biofilm explained the difference of nitrogen migration and transformation in river water under different hydrodynamic conditions. This study would help control the growth of biofilm and improve the nitrogen removal capacity of biofilm by regulating hydrodynamic conditions.}, } @article {pmid36397177, year = {2022}, author = {Wu, Y and Yu, Y and Hua, L and Wei, Y and Gan, Y and Chenia, HY and Wang, Y and Xie, X and Wang, J and Liu, M and Shao, G and Xiong, Q and Feng, Z}, title = {Genotyping and biofilm formation of Mycoplasma hyopneumoniae and their association with virulence.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {95}, pmid = {36397177}, issn = {1297-9716}, support = {CX(20)3090//Jiangsu Agricultural Science and Technology Innovation Fund/ ; 32172860//National Natural Science Foundation of China/ ; 32102675//National Natural Science Foundation of China/ ; }, mesh = {Animals ; *Biofilms ; Genotype ; Multilocus Sequence Typing/veterinary ; *Mycoplasma hyopneumoniae/genetics ; Swine ; *Swine Diseases/microbiology ; Virulence ; }, abstract = {Mycoplasma hyopneumoniae, the causative agent of swine respiratory disease, demonstrates differences in virulence. However, factors associated with this variation remain unknown. We herein evaluated the association between differences in virulence and genotypes as well as phenotype (i.e., biofilm formation ability). Strains 168 L, RM48, XLW-2, and J show low virulence and strains 232, 7448, 7422, 168, NJ, and LH show high virulence, as determined through animal challenge experiments, complemented with in vitro tracheal mucosa infection tests. These 10 strains with known virulence were then subjected to classification via multilocus sequence typing (MLST) with three housekeeping genes, P146-based genotyping, and multilocus variable-number tandem-repeat analysis (MLVA) of 13 loci. MLST and P146-based genotyping identified 168, 168 L, NJ, and RM48 as the same type and clustered them in a single branch. MLVA assigned a different sequence type to each strain. Simpson's index of diversity indicates a higher discriminatory ability for MLVA. However, no statistically significant correlation was found between genotypes and virulence. Furthermore, we investigated the correlation between virulence and biofilm formation ability. The strains showing high virulence demonstrate strong biofilm formation ability, while attenuated strains show low biofilm formation ability. Pearson correlation analysis revealed a significant positive correlation between biofilm formation ability and virulence. To conclude, there was no association between virulence and our genotyping data, but virulence was found to be significantly associated with the biofilm formation ability of M. hyopneumoniae.}, } @article {pmid36396071, year = {2022}, author = {Addo, KA and Li, L and Li, H and Yu, Y and Xiao, X}, title = {Osmotic stress relief antibiotic tolerance of 1,8-cineole in biofilm persister cells of Escherichia coli O157:H7 and expression of toxin-antitoxin system genes.}, journal = {Microbial pathogenesis}, volume = {173}, number = {Pt B}, pages = {105883}, doi = {10.1016/j.micpath.2022.105883}, pmid = {36396071}, issn = {1096-1208}, mesh = {Eucalyptol ; *Escherichia coli O157/genetics ; *Toxin-Antitoxin Systems ; Anti-Bacterial Agents/pharmacology ; Osmotic Pressure ; Biofilms ; DNA-Binding Proteins ; *Escherichia coli Proteins/genetics ; }, abstract = {The control of E. coli activity from forming biofilm and persister cells is an essential factor in both the health and food industries. The efficacy of antimicrobial treatment is often limited due to their low penetrability as biofilm formation protect cells within from physical or chemical threats. Among other factors, osmotic stress has shown to have a high capacity to enhance the antimicrobial activities against various pathogens. Thus, this study aimed to test the hypothesis that the antimicrobial activity of cineole (CN) could be enhanced under osmotic stress to inhibit biofilm and persister cells. Time-kill analysis revealed that CN under NaCl-induced osmotic stress (CN-S) had better inhibitory effect on E. coli biofilm. 5% CN-S altered the integrity, hydration, motilities and exopolysaccharide production of E. coli cells. Also, the outer membrane permeability, surface roughness and hydrophobicity which determine initial cell adhesion, aggregation and colony assembly were significantly perturbed. Furthermore, the expression levels of virulence genes stx1, stx2, eae, flhD, and the TA system antitoxin genes mazE, hipB were downregulated. When applied to cucumber, the rate of increase in internalized bacterial cells significantly reduced after storage at 4 °C for 48 h. Thus, the results suggested that the application of osmotic stress could minimize the working concentration of antimicrobials in real food systems, which could be helpful in counteracting the growing concern of microbial resistance.}, } @article {pmid36395854, year = {2023}, author = {Li, J and Liu, H and Wu, P and Zhang, C and Zhang, J}, title = {Quorum sensing signals stimulate biofilm formation and its electroactivity for chain elongation: System performance and underlying mechanisms.}, journal = {The Science of the total environment}, volume = {859}, number = {Pt 1}, pages = {160192}, doi = {10.1016/j.scitotenv.2022.160192}, pmid = {36395854}, issn = {1879-1026}, mesh = {RNA, Ribosomal, 16S ; *Quorum Sensing ; *Acyl-Butyrolactones/analysis ; Biofilms ; Electrodes ; }, abstract = {Quorum sensing signals have been widely explored in microbial communities. However, the impact of chain elongation microorganisms by quorum sensing signals of acyl homoserine lactones (AHLs) is still unclear. Here, chain elongation consortia under conditions of AHLs addition were examined in microbial electrosynthesis (MES) through 16S rRNA microbial community and metatranscriptomic analyses. The research found that N-octanoyl-L-homoserine lactone (C8-HSL) increased the caproate concentration by 61.48 % as relative to the control and showed the best performance among all the tested AHLs in MES. AHLs enhanced the redox activity of cathodic electroactive biofilms (EABs), which could be due to increased attachment of electrode microorganisms and ratios of live/dead cells. Microbial community analysis showed that AHLs increased the relative abundance of Negativicutes obviously. Meanwhile, metatranscriptomic analysis revealed that C8-HSL significantly improved CoA - transferase activity and regulated valine, leucine, isoleucine biosynthesis, and carbon metabolism. Besides, C8-HSL was beneficial to the chain elongation metabolic pathways, especially the fatty acid biosynthesis (FAB) pathway. These results not only provide metabolic insights into AHLs regulating chain elongation consortia, but also propose potential strategies for speeding up the formation of MES cathodic biofilm.}, } @article {pmid36395642, year = {2023}, author = {Ma, S and Huang, Y and Zhang, B and Zhu, X and Xia, A and Zhu, X and Liao, Q}, title = {Comprehensive modeling and predicting light transmission in microalgal biofilm.}, journal = {Journal of environmental management}, volume = {326}, number = {Pt A}, pages = {116757}, doi = {10.1016/j.jenvman.2022.116757}, pmid = {36395642}, issn = {1095-8630}, mesh = {*Microalgae ; Biofilms ; Photobioreactors ; Biomass ; Biotechnology ; }, abstract = {Biofilm-based microalgae culture combined with wastewater treatment is a promising biotechnology for environmental management. Light availability influences the accumulation of microalgal biomass and nutrient removal. A light attenuation model which comprehensively considered microalgal biofilm structure (density and biofilm thickness), pigments content, and extracellular polymeric substances content was developed to predict the light attenuation in biofilm according to the simplification of the radiative transfer equation. The predicted results were in good overall agreement with the experiment, with an average error of less than 9.02%. These factors (biofilm density, thickness, pigments content, and extracellular polymeric substances content) all contributed to the light intensity attenuation, but biofilm thickness caused the most dramatic attenuation under the same increment of relative change in actual culture. The scattering coefficient of the biofilm (0.433 m[2]/g) was less than that of the suspension (1.489 m[2]/g) under white incident light. It suggests that the dense structure of cells allows much light to be concentrated in the forward direction when transmitting. This model could be adopted to predict the light distribution in microalgal biofilm for the further design of efficient photobioreactors and the development of light optimization strategies.}, } @article {pmid36395161, year = {2022}, author = {Dargahi, Z and Hamad, AA and Sheikh, AF and Ahmad Khosravi, N and Samei Fard, S and Motahar, M and Mehr, FJ and Abbasi, F and Meghdadi, H and Bakhtiyariniya, P and Heydari, R and Moradi, M and Asareh Zadegan Dezfuli, A}, title = {The biofilm formation and antibiotic resistance of bacterial profile from endotracheal tube of patients admitted to intensive care unit in southwest of Iran.}, journal = {PloS one}, volume = {17}, number = {11}, pages = {e0277329}, pmid = {36395161}, issn = {1932-6203}, mesh = {Humans ; *Staphylococcus aureus ; Iran ; Drug Resistance, Microbial ; Intensive Care Units ; *Pneumonia, Ventilator-Associated/drug therapy ; Bacteria ; Intubation, Intratracheal/adverse effects ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Pseudomonas aeruginosa ; }, abstract = {Ventilator-associated pneumonia (VAP) is a prevalent nosocomial illness in mechanically ventilated patients. Hence, the aim of this study was to investigate the pattern of antibiotic resistance and biofilm formation of bacterial profiles from Endotracheal Tubes of patients hospitalized in an intensive care unit in southwest Iran. According to the standard operating method, the microbiological laboratory conducts bacteria culture and susceptibility testing on endotracheal Tube samples suspected of carrying a bacterial infection. The Clinical and laboratory standards institute (CLSI) techniques are used to determine the Antimicrobial resistance (AMR) of bacterial isolates to antibiotics using the disk diffusion method. The crystal violet staining method was used to assess the biofilm-forming potential of isolates in a 96-well microtiter plate. In total, (51%) GPBs were included in this study. The isolated GPB were coagulase-negative Staphylococcus (16%), S. aureus (14%). In total, (40%) of GNB were included in this study. The isolated GNB were Klebsiella spp. (36%), A. baumannii (22%), P. aeruginosa (35%). (32%) bacterial strains were MDR and (29%) strains were XDR. The results of biofilm formation showed (72%) were biofilm producers. VAP is a common and severe nosocomial infection in mechanically ventilated patients. Controlling biofilm formation, whether on the ET or in the oropharyngeal cavity, is thus an important technique for treating VAP. Colistin and linezolid are antibiotics that are effective against practically all resistant GNB and GPB isolates.}, } @article {pmid36394350, year = {2022}, author = {Shahina, Z and Ndlovu, E and Persaud, O and Sultana, T and Dahms, TES}, title = {Candida albicans Reactive Oxygen Species (ROS)-Dependent Lethality and ROS-Independent Hyphal and Biofilm Inhibition by Eugenol and Citral.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0318322}, pmid = {36394350}, issn = {2165-0497}, mesh = {Infant, Newborn ; Humans ; *Candida albicans ; Eugenol/pharmacology ; Antifungal Agents/pharmacology ; Reactive Oxygen Species ; *Oils, Volatile/pharmacology/chemistry ; Biofilms ; Plant Oils/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Candida albicans is part of the normal human flora but is most frequently isolated as the causative opportunistic pathogen of candidiasis. Plant-based essential oils and their components have been extensively studied as antimicrobials, but their antimicrobial impacts are poorly understood. Phenylpropenoids and monoterpenes, for example, eugenol from clove and citral from lemon grass, are potent antifungals against a wide range of pathogens. We report the cellular response of C. albicans to eugenol and citral, alone and combined, using biochemical and microscopic assays. The MICs of eugenol and citral were 1,000 and 256 μg/mL, respectively, with the two exhibiting additive effects based on a fractional inhibitory concentration index of 0.83 ± 0.14. High concentrations of eugenol caused membrane damage, oxidative stress, vacuole segregation, microtubule dysfunction and cell cycle arrest at the G1/S phase, and while citral had similar impacts, they were reactive oxygen species (ROS) independent. At sublethal concentrations (1/2 to 1/4 MIC), both oils disrupted microtubules and hyphal and biofilm formation in an ROS-independent manner. While both compounds disrupt the cell membrane, eugenol had a greater impact on membrane dysfunction. This study shows that eugenol and citral can induce vacuole and microtubule dysfunction, along with the inhibition of hyphal and biofilm formation. IMPORTANCE Candida albicans is a normal resident on and in the human body that can cause relatively benign infections. However, when our immune system is severely compromised (e.g., cancer chemotherapy patients) or underdeveloped (e.g., newborns), this fungus can become a deadly pathogen, infecting the bloodstream and organs. Since there are only a few effective antifungal agents that can be used to combat fungal infections, these fungi have been exposed to them over and over again, allowing the fungi to develop resistance. Instead of developing antifungal agents that kill the fungi, some of which have undesirable side effects on the human host, researchers have proposed to target the fungal traits that make the fungus more virulent. Here, we show how two components of plant-based essential oils, eugenol and citral, are effective inhibitors of C. albicans virulence traits.}, } @article {pmid36389263, year = {2022}, author = {Shailaja, A and Bruce, TF and Gerard, P and Powell, RR and Pettigrew, CA and Kerrigan, JL}, title = {Comparison of cell viability assessment and visualization of Aspergillus niger biofilm with two fluorescent probe staining methods.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100090}, pmid = {36389263}, issn = {2590-2075}, support = {P20 GM146584/GM/NIGMS NIH HHS/United States ; }, abstract = {Filamentous fungi are ubiquitous and frequent components of biofilms. A means to visualize them and quantify their viability is essential for understanding their development and disruption. However, quantifying filamentous fungal biofilms poses challenges because, unlike yeasts and bacteria, they are not composed of discrete cells of similar size. This research focused on filamentous fungal biofilms that are representative of those in the built environment. The objective of this study was to develop a rapid method to examine biofilm structure and quantify live (metabolically active/ membrane undamaged) and dead (inactive/ membrane damaged) cells in Aspergillus niger biofilms utilizing a fluorescent probe staining method and confocal laser scanning microscopy (CLSM). For this, we compared two commercially available probe staining kits that have been developed for bacterial and yeast systems. One method utilized the classic cell stain FUN 1 that exhibits orange-red fluorescent intravacuolar structures in metabolically active cells, while dead cells are fluoresced green. The second method utilized a combination of SYTO9 and propidium iodide (PI), and stains cells based on their membrane morphology. SYTO9 is a green fluorescent stain with the capacity to penetrate the living cell walls, and PI is a red fluorescent stain that can only penetrate dead or dying cells with damaged cell membranes. Following staining, the biofilms were imaged using CLSM and biofilm volumes and thickness were quantified using COMSTAT, a computer program that measures biofilm accumulation from digital image stacks. The results were compared to independent measurements of live-dead cell density, as well as a classic cell viability assay-XTT. The data showed that the combination of SYTO9 and PI is optimal for staining filamentous fungal biofilms.}, } @article {pmid36389262, year = {2022}, author = {Garcia, KA and McLee, P and Schuler, AJ}, title = {Effects of media length on biofilms and nitrification in moving bed biofilm reactors.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100091}, pmid = {36389262}, issn = {2590-2075}, abstract = {Biofilms grown on free-floating plastic media are increasingly being used to cultivate biofilms in integrated fixed film activated sludge (IFAS) and moving bed bioreactor (MBBR) systems for wastewater treatment with the common goal of increasing nitrogen removal. Fundamental principles of fluid dynamics dictate that the length of internal media channels affects fluid velocities and shear forces across biofilm surfaces, which in turn should affect rates of mass transfer and biofilm growth and activity, but little is known about media length effects on water quality and biofilm characteristics. It was hypothesized that length affects biofilm thickness, microbial populations and their activities, and system performance. Nitrification rates and biofilm characteristics were monitored in parallel continuous flow, bench-scale MBBRs systems with media length as a controlled variable. Longer media produced biofilms with approximately twice the thickness and twice the mass per unit area than did media with one-third their length. Based on calculated head losses, the combined effects of length and constriction of internal channels led to an estimated 77% reduction in fluid velocity through the longer media relative to the shorter media. Longer media demonstrated more rapid development of nitrite oxidizing bacteria (NOB) activity than the shorter media over much of the study, as indicated by measurements of nitrite and nitrate, but AOB activity was similar in the two media. Both biomass and NOB activity were concentrated toward media ends, while ammonia oxidizing bacteria (AOB) activity was uniformly distributed across the media, based on testing of sectioned media. 16s rRNA amplicon sequencing indicated the presence of several putative heterotrophic nitrifying families, particularly Xanthomonadaceae, Comamonadadeae and Microbacteriaceae, as well as the autotrophic Bradyrhizobiacea (which includes the NOB Nitrobacter) were common on both media throughout the study. The short media enriched for Nitrosomonadaceae, which includes the AOB genus Nitrosomonas, while minimal autotrophic AOBs were found in the long media biofilm. These results provide insights to the design of media for improved performance, particularly with respect to nitrite versus nitrate production, which may be useful to improve nitrification and for energy saving processes for nitrogen removal such as deammonification. The research also provides fundamental insights regarding the effects of media geometry on biofilm structure and function, which advances our understanding of environmental factors affecting biofilm development.}, } @article {pmid36388058, year = {2022}, author = {Rivera, ES and Weiss, A and Migas, LG and Freiberg, JA and Djambazova, KV and Neumann, EK and Van de Plas, R and Spraggins, JM and Skaar, EP and Caprioli, RM}, title = {Imaging mass spectrometry reveals complex lipid distributions across Staphylococcus aureus biofilm layers.}, journal = {Journal of mass spectrometry and advances in the clinical lab}, volume = {26}, number = {}, pages = {36-46}, pmid = {36388058}, issn = {2667-145X}, support = {F32 AI169905/AI/NIAID NIH HHS/United States ; T32 AI007474/AI/NIAID NIH HHS/United States ; }, abstract = {INTRODUCTION: Although Staphylococcus aureus is the leading cause of biofilm-related infections, the lipidomic distributions within these biofilms is poorly understood. Here, lipidomic mapping of S. aureus biofilm cross-sections was performed to investigate heterogeneity between horizontal biofilm layers.

METHODS: S. aureus biofilms were grown statically, embedded in a mixture of carboxymethylcellulose/gelatin, and prepared for downstream matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS). Trapped ion mobility spectrometry (TIMS) was also applied prior to mass analysis.

RESULTS: Implementation of TIMS led to a ∼ threefold increase in the number of lipid species detected. Washing biofilm samples with ammonium formate (150 mM) increased signal intensity for some bacterial lipids by as much as tenfold, with minimal disruption of the biofilm structure. MALDI TIMS IMS revealed that most lipids localize primarily to a single biofilm layer, and species from the same lipid class such as cardiolipins CL(57:0) - CL(66:0) display starkly different localizations, exhibiting between 1.5 and 6.3-fold intensity differences between layers (n = 3, p < 0.03). No horizontal layers were observed within biofilms grown anaerobically, and lipids were distributed homogenously.

CONCLUSIONS: High spatial resolution analysis of S. aureus biofilm cross-sections by MALDI TIMS IMS revealed stark lipidomic heterogeneity between horizontal S. aureus biofilm layers demonstrating that each layer was molecularly distinct. Finally, this workflow uncovered an absence of layers in biofilms grown under anaerobic conditions, possibly indicating that oxygen contributes to the observed heterogeneity under aerobic conditions. Future applications of this workflow to study spatially localized molecular responses to antimicrobials could provide new therapeutic strategies.}, } @article {pmid36386714, year = {2022}, author = {Zarei, M and Rahimi, S and Saris, PEJ and Yousefvand, A}, title = {Pseudomonas fluorescens group bacterial strains interact differently with pathogens during dual-species biofilm formation on stainless steel surfaces in milk.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1053239}, pmid = {36386714}, issn = {1664-302X}, abstract = {In order to develop strategies for preventing biofilm formation in the dairy industry, a deeper understanding of the interaction between different species during biofilm formation is necessary. Bacterial strains of the P. fluorescens group are known as the most important biofilm-formers on the surface of dairy processing equipment that may attract and/or shelter other spoilage or pathogenic bacteria. The present study used different strains of the P. fluorescens group as background microbiota of milk, and evaluated their interaction with Staphylococcus aureus, Bacillus cereus, Escherichia coli O157:H7, and Salmonella Typhimurium during dual-species biofilm formation on stainless steel surfaces. Two separate scenarios for dual-species biofilms were considered: concurrent inoculation of Pseudomonas and pathogen (CI), and delayed inoculation of pathogen to the pre-formed Pseudomonas biofilm (DI). The gram-positive pathogens used in this study did not form dual-species biofilms with P. fluorescens strains unless they were simultaneously inoculated with Pseudomonas strains. E. coli O157:H7 was able to form dual-species biofilms with all seven P. fluorescens group strains, both in concurrent (CI) and delayed (DI) inoculation. However, the percentage of contribution varied depending on the P. fluorescens strains and the inoculation scenario. S. Typhimurium contributed to biofilm formation with all seven P. fluorescens group strains under the CI scenario, with varying degrees of contribution. However, under the DI scenario, S. Typhimurium did not contribute to the biofilm formed by three of the seven P. fluorescens group strains. Overall, these are the first results to illustrate that the strains within the P. fluorescens group have significant differences in the formation of mono-or dual-species biofilms with pathogenic bacteria. Furthermore, the possibility of forming dual-species biofilms with pathogens depends on whether the pathogens form the biofilm simultaneously with the P. fluorescens group strains or whether these strains have already formed a biofilm.}, } @article {pmid36386632, year = {2022}, author = {Dey, SS and Hossain, ZZ and Akhter, H and Jensen, PKM and Begum, A}, title = {Abundance and biofilm formation capability of Vibrio cholerae in aquatic environment with an emphasis on Hilsha fish (Tenualosa ilisha).}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {933413}, pmid = {36386632}, issn = {1664-302X}, abstract = {The potentially deadly and sporadic diarrhea-causing agent, Vibrio cholerae, is present in a great number in the freshwater aquatic environment and can be transmitted to humans by different aquatic organisms. In the perspective of Bangladesh, an anadromous fish species Hilsha (Tenualosa ilisha) can act as a transmission vehicle of V. cholerae from the aquatic to the household kitchen environment. The present study was carried out to investigate the presence of V. cholerae in the aquatic habitat of Bangladesh with a major emphasis on freshly caught Hilsha fish, along with river water and plankton samples from the fish capture site. The study also detected the biofilm formation capability of V. cholerae within Hilsha fish that might help the transmission and persistence of the pathogen in aquatic habitat. Twenty out of 65 freshly caught fish (30.8%) and 1 out of 15 water samples (6.67%) showed the presence of V. cholerae and none of the plankton samples were positive for V. cholerae. The isolated strains were identified as non-O1 and non-O139 serogroups of V. cholerae and contain some major toxin and virulence genes. A few strains showed cellular cytotoxicity on the HeLa cell line. All strains were able to form biofilm on the microtiter plate and the detection of three genes related to biofilm formation (vpsA, vpsL, and vpsR) were also assayed using qPCR. In this study, the in vitro biofilm formation ability of the isolated strains may indicate the long-term persistence of V. cholerae in different parts of Hilsha fish. The abundance of V. cholerae only in freshly caught Hilsha fish and the absence of the pathogen in the surrounding aquatic environment could stipulate the role of Hilsha fish as one of the major transmission routes of V. cholerae from the freshwater aquatic environment of Bangladesh to the household kitchen environment.}, } @article {pmid36385439, year = {2023}, author = {Zhao, F and Su, Y and Wang, J and Romanova, S and DiMaio, DJ and Xie, J and Zhao, S}, title = {A Highly Efficacious Electrical Biofilm Treatment System for Combating Chronic Wound Bacterial Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {35}, number = {6}, pages = {e2208069}, pmid = {36385439}, issn = {1521-4095}, support = {NIAMS R21 AR080906/GM/NIGMS NIH HHS/United States ; P30 GM127200/GM/NIGMS NIH HHS/United States ; //COBRE Nebraska Center for Nanomedicine/ ; R21 AR080906/AR/NIAMS NIH HHS/United States ; R01 GM138552/GM/NIGMS NIH HHS/United States ; NIGMS R01 GM138552/GM/NIGMS NIH HHS/United States ; NIAMS R21 AR078439/GM/NIGMS NIH HHS/United States ; R21 AR078439/AR/NIAMS NIH HHS/United States ; P30GM127200/GM/NIGMS NIH HHS/United States ; }, mesh = {Mice ; Animals ; *Methicillin-Resistant Staphylococcus aureus ; *Bacterial Infections/drug therapy ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Disease Models, Animal ; *Wound Infection/drug therapy/microbiology ; *Staphylococcal Infections/drug therapy ; }, abstract = {Biofilm infection has a high prevalence in chronic wounds and can delay wound healing. Current treatment using debridement and antibiotic administration imposes a significant burden on patients and healthcare systems. To address their limitations, a highly efficacious electrical antibiofilm treatment system is described in this paper. This system uses high-intensity current (75 mA cm[-2]) to completely debride biofilm above the wound surface and enhance antibiotic delivery into biofilm-infected wounds simultaneously. Combining these two effects, this system uses short treatments (≤2 h) to reduce bacterial count of methicillin-resistant S. aureus (MRSA) biofilm-infected ex vivo skin wounds from 10[10] to 10[5.2] colony-forming units (CFU) g[-1] . Taking advantage of the hydrogel ionic circuit design, this system enhances the in vivo safety of high-intensity current application compared to conventional devices. The in vivo antibiofilm efficacy of the system is tested using a diabetic mouse-based wound infection model. MRSA biofilm bacterial count decreases from 10[9.0] to 10[4.6] CFU g[-1] at 1 day post-treatment and to 10[3.3] CFU g[-1] at 7 days post-treatment, both of which are below the clinical threshold for infection. Overall, this novel technology provides a quick, safe, yet highly efficacious treatment to chronic wound biofilm infections.}, } @article {pmid36384653, year = {2022}, author = {Mohammadian, F and Rahmani, HK and Bidarian, B and Khoramian, B}, title = {Isolation and evaluation of the efficacy of bacteriophages against multidrug-resistant (MDR), methicillin-resistant (MRSA) and biofilm-producing strains of Staphylococcus aureus recovered from bovine mastitis.}, journal = {BMC veterinary research}, volume = {18}, number = {1}, pages = {406}, pmid = {36384653}, issn = {1746-6148}, support = {3/53878//Ferdowsi University of Mashhad/ ; }, mesh = {Cattle ; Female ; Animals ; *Mastitis, Bovine/therapy ; Staphylococcus aureus ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Methicillin Resistance ; *Staphylococcal Infections/therapy/veterinary ; Staphylococcus Phages ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Cattle Diseases ; }, abstract = {BACKGROUND: Staphylococcus aureus (S. aureus) is one of the major causes of bovine mastitis with significant economic losses around the worldwide. The emergence of multidrug-resistant (MDR), methicillin-resistant (MRSA) and biofilm-producing strains of S. aureus challenges the treatment strategies based on the antibiotic application. Today, alternative or combinational treatment options such as bacteriophage application has received much attention. The goal of the present study was to focus on isolation and evaluation of the efficacy of bacteriophages with specific lytic activity against S. aureus strains with low cure rates (MDR, MRSA and biofilm-producing strains).

RESULTS: In the present study, two phages belonging to the Podoviridae family with specific lytic activity against S. aureus were isolated from the sewage of dairy farms and designated as Staphylococcus phage M8 and Staphylococcus phage B4. Latent period and burst size for Staphylococcus phage M8 (70 min, 72 PFU/cell) and Staphylococcus phage B4 (30 min, 447 PFU/cell) were also defined. Our results revealed the susceptibility of MDR (4/20; 20%), MRSA (4/13; 30.8%) and biofilm-producing (1/10; 10%) strains to Staphylococcus phage M8. Moreover, one biofilm-producing strain (1/10; 10%) was susceptible to Staphylococcus phage B4. Furthermore, both phages kept their lytic activity in milk. They reduced the S. aureus population by about 3 logs in cultured milk after 8 h of incubation.

CONCLUSION: In conclusion, it seems that both phages had the potential to serve as biological control agents alone or in combination with other agents such as antibiotics against infections induced by S. aureus. However, further studies are needed to investigate the efficacy of these phages in vivo.}, } @article {pmid36383258, year = {2022}, author = {Govindarajan, DK and Meghanathan, Y and Sivaramakrishnan, M and Kothandan, R and Muthusamy, A and Seviour, TW and Kandaswamy, K}, title = {Enterococcus faecalis thrives in dual-species biofilm models under iron-rich conditions.}, journal = {Archives of microbiology}, volume = {204}, number = {12}, pages = {710}, pmid = {36383258}, issn = {1432-072X}, support = {SRG/2019/000094//Science and Engineering Research Board/ ; }, mesh = {Humans ; *Enterococcus faecalis ; Escherichia coli/metabolism ; Biofilms ; *Urinary Tract Infections/microbiology ; Iron/metabolism ; Carrier Proteins/metabolism ; }, abstract = {Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis) are pathogenic strains that often coexist in intestinal flora of humans and are prone to cause biofilm-associated infections, such as gastrointestinal tract and urinary tract infections. Earlier studies have demonstrated that E. faecalis biofilm can metabolize ferrous ions in iron-rich environments and promote biofilm growth under in-vivo conditions. However, the influence of iron transporters on dual-species biofilm growth and the nature of molecular-level interactions between iron transporter proteins and Fe[2+] remains unknown. Therefore, in this work, co-culture studies were performed and the study indicates that Fe[2+] at concentrations of 50-150 µM promotes the colonization of E. coli, and Fe[2+] concentrations of 50-200 µM promote the growth of E. faecalis and dual-species colonies. Atomic absorption spectroscopy results reveal that Fe[2+] ion augmentation in bacterial cells was increased to 4 folds in the single-species model and 11 folds in the dual-species model under iron-supplemented conditions. Furthermore, Fe[2+] augmentation increased the antibiotic resistance of E. faecalis in both single- and dual-species bacterial cultures. In addition, in-silico docking were performed to determine a three-dimensional (3D) structure of ferrous iron-transporter proteins FeoB of E. faecalis and its affinity to extracellular Fe[2+]. Our model suggests that the FeoB facilitates the Fe[2+] uptake in E. faecalis cells in the absence of iron chelator, 2,2-bipyridyl.}, } @article {pmid36379967, year = {2022}, author = {Celiksoy, V and Moses, RL and Sloan, AJ and Moseley, R and Heard, CM}, title = {Synergistic activity of pomegranate rind extract and Zn (II) against Candida albicans under planktonic and biofilm conditions, and a mechanistic insight based upon intracellular ROS induction.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {19560}, pmid = {36379967}, issn = {2045-2322}, mesh = {Humans ; *Candida albicans ; Antifungal Agents/pharmacology ; Plankton ; Reactive Oxygen Species/pharmacology ; *Pomegranate ; Microbial Sensitivity Tests ; Biofilms ; Plant Extracts/pharmacology ; Zinc/pharmacology ; }, abstract = {Candida albicans (C. albicans) is an opportunistic pathogen, which causes superficial infection and can lead to mortal systemic infections, especially in immunocompromised patients. The incidence of C. albicans infections is increasing and there are a limited number of antifungal drugs used in treatment. Therefore, there is an urgent need for new and alternative antifungal drugs. Pomegranate rind extract (PRE) is known for its broad-spectrum antimicrobial activities, including against C. albicans and recently, PRE and Zn (II) have been shown to induce synergistic antimicrobial activity against various microbes. In this study, the inhibitory activities of PRE, Zn (II) and PRE in combination with Zn (II) were evaluated against C. albicans. Antifungal activities of PRE and Zn (II) were evaluated using conventional microdilution methods and the interaction between these compounds was assessed by in vitro checkerboard and time kill assays in planktonic cultures. The anti-biofilm activities of PRE, Zn (II) and PRE in combination with Zn (II) were assessed using confocal laser scanning microscopy, with quantitative analysis of biofilm biomass and mean thickness analysed using COMSTAT2 analysis. In addition, antimicrobial interactions between PRE and Zn (II) were assayed in terms reactive oxygen species (ROS) production by C. albicans. PRE and Zn (II) showed a potent antifungal activity against C. albicans, with MIC values of 4 mg/mL and 1.8 mg/mL, respectively. PRE and Zn (II) in combination exerted a synergistic antifungal effect, as confirmed by the checkerboard and time kill assays. PRE, Zn (II) and PRE and Zn (II) in combination gave rise to significant reductions in biofilm biomass, although only PRE caused a significant reduction in mean biofilm thickness. The PRE and Zn (II) in combination caused the highest levels of ROS production by C. albicans, in both planktonic and biofilm forms. The induction of excess ROS accumulation in C. albicans may help explain the synergistic activity of PRE and Zn (II) in combination against C. albicans in both planktonic and biofilm forms. Moreover, the data support the potential of the PRE and Zn (II) combination as a novel potential anti-Candida therapeutic system.}, } @article {pmid36379534, year = {2022}, author = {Alfhili, MA and Ahmad, I and Alraey, Y and Alangari, A and Alqahtani, T and Dera, AA}, title = {Antibacterial and anti-biofilm activity of plumbagin against multi-drug resistant clinical bacterial isolates.}, journal = {Saudi medical journal}, volume = {43}, number = {11}, pages = {1224-1233}, doi = {10.15537/smj.2022.43.11.20220446}, pmid = {36379534}, issn = {1658-3175}, mesh = {Humans ; *Staphylococcus aureus ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology ; Drug Resistance, Multiple, Bacterial ; Escherichia coli ; *Staphylococcal Infections ; }, abstract = {OBJECTIVES: To evaluate the antibacterial activity of plumbagin (PGN) against multidrug resistance (MDR) clinical isolates.

METHODS: This study was carried out at the Department of Clinical Lab Sciences, King Khalid University from October 6, 2021 to December 14, 2021. We investigated the antibacterial and anti-virulence activity of PGN against MDR Gram-negative (Escherichia coli, Klebsiella pneumoniae, Salmonella Typhi, and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus [S. aureus], Staphylococcus saprophyticus [S. saprophyticus], Streptococcus pyogenes, and Enterococcus faecalis) clinical bacterial isolates. Agar well diffusion, microdilution assay, colony count method, biofilm formation, and time-kill kinetics were employed to probe the MIC, MBC, and anti-virulence activity of PGN.

RESULTS: Plumbagin inhibited the growth of all tested isolates, with S. saprophyticus exhibiting the highest sensitivity. MIC values ranged from 0.029 to 0.117 µg/mL whereas MBC ranged from 0.235 to 0.94 µg/mL, with 79% to 99% growth inhibition. Moreover, all tested isolates showed a marked decrease in biofilm formation, with S. saprophyticus and S. aureus being the most sensitive.

CONCLUSION: Plumbagin is a stand-alone, broad spectrum antibacterial with promising potential against the rising threat of antimicrobial resistance.}, } @article {pmid36379332, year = {2023}, author = {Liu, Y and Zhang, B and Han, YH and Yao, Y and Guo, P}, title = {Involvement of exogenous arsenic-reducing bacteria in root surface biofilm formation promoted phytoextraction of arsenic.}, journal = {The Science of the total environment}, volume = {858}, number = {Pt 3}, pages = {160158}, doi = {10.1016/j.scitotenv.2022.160158}, pmid = {36379332}, issn = {1879-1026}, mesh = {*Arsenic ; Bacteria ; }, abstract = {Root surface biofilm (RSB) is the last window for pollutants entering plant roots and thus plays a critical role in the phytoextraction of pollutants. Exogenous arsenic-reducing bacteria (EARB) have been adopted to enhance the phytoextraction of arsenic (As). However, whether EARB would be involved in RSB formation together with indigenous bacteria and the role of EARB involvement in As phytoextraction are still unknown. Herein, two EARB strains and two phytoextractors (wheat and maize) were selected to investigate the involvement of EARB in RSB formation and its role in As phytoextraction. Results showed that EARB successfully participated in RSB formation together with indigenous bacteria, attributing to their strong chemotaxis and biofilm formation abilities induced by root exudates. The involvement of EARB in RSB formation significantly enhanced As accumulation in plant roots, since more arsenite (As(III)) caused by arsenate (As(V)) reduction in RSB was absorbed by roots. Its underlying mechanism was further elucidated. EARB involvement increased phylum Proteobacteria to produce more siderophores in RSB. Siderophores then improved photosynthesis by increasing catalase and peroxidase activities and decreasing the malondialdehyde of plants. These actions further raised the shoot fresh weight to enhance As accumulation in plant roots. Moreover, mesophyll cell in wheat has a stronger As(V) reduction ability than that in maize, resulting in opposite distribution patterns of As(III) and As(V) in wheat and maize shoots. This study provides a new understanding of phytoextraction enhanced by exogenous bacteria and fills the gap in the role of EARB in As phytoextraction from the perspective of the RSB microregion.}, } @article {pmid36379170, year = {2023}, author = {Rindi, L and Benedetti-Cecchi, L}, title = {Short-term stability of rocky intertidal biofilm to nitrogen and phosphorus pulses.}, journal = {Marine environmental research}, volume = {183}, number = {}, pages = {105795}, doi = {10.1016/j.marenvres.2022.105795}, pmid = {36379170}, issn = {1879-0291}, mesh = {*Nitrogen ; *Ecosystem ; Phosphorus ; Biomass ; Biofilms ; Eutrophication ; }, abstract = {Coastal environments experience both natural and anthropogenic inputs of nitrogen (N) and phosphorus (P). Agricultural fertilisers, organic run-offs, and edaphic characteristics of coastal environments may generate mosaics of nutrient concentrations that ultimately influence the coastal primary productivity. Here, we experimentally assessed the effects of repeated pulses of N and P on multiple components of ecological stability (sensitivity, resilience, temporal stability and recovery) of phototrophic rocky intertidal biofilm. We performed a repeated-pulses factorial experiment crossing increasing N and P concentrations chosen to reflect a range of nutrient enrichment conditions, from oligotrophic to eutrophic. N and P, regardless of concentration or whether they occurred in isolation or combination, enhanced biofilm's sensitivity (increased biomass or physiological performance compared to controls) without altering resilience. Our experiment illustrates how the stability of an essential coastal primary producer responds to increasing N and P supply levels. Furthermore, notwithstanding the importance of decomposing the multiple dimensions of stability, the transitory increase of the sole sensitivity indicated that rocky shore biofilm is robust against a wide range of nutrient enrichment.}, } @article {pmid36378180, year = {2022}, author = {Yang, C and Houweling, D and He, H and Daigger, GT}, title = {Available online sensors can be used to create fingerprints for MABRs that characterize biofilm limiting conditions and serve as soft sensors.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {9}, pages = {2270-2287}, doi = {10.2166/wst.2022.323}, pmid = {36378180}, issn = {0273-1223}, mesh = {*Bioreactors ; *Ammonia ; Biofilms ; Wastewater ; Oxygen ; Waste Disposal, Fluid ; }, abstract = {Membrane aerated biofilm reactors (MABRs) are a promising biological wastewater treatment technology, whose industrial applications have dramatically accelerated in the last five years. Increased popularity and fast industrial adaptation are coupled with increased needs to monitor, optimize, and control MABRs with available online sensors. Observations of commercial scale MABR installations have shown a distinctive and repetitive pattern relating oxygen purity in MABR exhaust gas to reactor ammonia concentrations. This provides an obvious opportunity for process monitoring and control which this paper investigates with the help of modeling. The relationship plots between the bulk ammonia concentration and the oxygen purity are defined as MABR fingerprint plots, which are described in the form of steady-state curves and dynamic trajectories. This study systematically investigated, analyzed, and explained the behaviors and connections of steady-state curves and dynamic trajectories with a MABR model in SUMO[®], and proposed a hypothesis about utilizing the MABR fingerprint plots to characterize MABR system performance, identify the limiting factor of biofilms, and possibly develop a soft senor for MABR biofilm thickness monitoring and control.}, } @article {pmid36377868, year = {2022}, author = {Zarnowski, R and Massey, J and Mitchell, AP and Andes, D}, title = {Extracellular Vesicles Contribute to Mixed-Fungal Species Competition during Biofilm Initiation.}, journal = {mBio}, volume = {13}, number = {6}, pages = {e0298822}, pmid = {36377868}, issn = {2150-7511}, support = {T32 AI055397/AI/NIAID NIH HHS/United States ; }, mesh = {*Biofilms ; Candida ; Extracellular Matrix/metabolism ; *Extracellular Vesicles ; Candida albicans ; }, abstract = {Extracellular vesicles commonly modulate interactions among cellular communities. Recent studies demonstrate that biofilm maturation features, including matrix production, drug resistance, and dispersion, require the delivery of a core protein and carbohydrate vesicle cargo in Candida species. The function of the vesicle cargo for these advanced-phase biofilm characteristics appears to be conserved across Candida species. Mixed-species interactions in mature biofilms indicate that vesicle cargo serves a cooperative role in preserving the community. Here, we define the function of biofilm-associated vesicles for biofilm initiation both within and among five species across the Candida genus. We found similar vesicle cargo functions for several conserved proteins across species, based on the behavior of mutants. Repletion of the adhesion environment with wild-type vesicles returned the community phenotype toward reference levels in intraspecies experiments. However, cross-species vesicle complementation did not restore the wild-type biology and in fact drove the phenotype in the opposite direction for most cross-species interactions. Further study of mixed-species biofilm adhesion and exogenous wild-type vesicle administration similarly demonstrated competitive interactions. Our studies indicate that similar vesicle cargoes contribute to biofilm initiation. However, vesicles from disparate species serve an interference competitive role in mixed-Candida species scenarios. IMPORTANCE Candida species commonly form mixed-species biofilms with other Candida species and bacteria. In the established biofilm state, vesicle cargo delivers public goods to support the mature community. At biofilm initiation, however, vesicles play a negative role in cross-species interactions, presumably to allow species to gain a survival advantage. These observations and recent reports reveal that vesicle cargo has both cooperative and competitive roles among Candida species, depending on the needs of the community biofilm formation.}, } @article {pmid36376525, year = {2023}, author = {Gelardi, M and Giancaspro, R and Cassano, M}, title = {Biofilm in sino-nasal infectious diseases: the role nasal cytology in the diagnostic work up and therapeutic implications.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {280}, number = {4}, pages = {1523-1528}, pmid = {36376525}, issn = {1434-4726}, mesh = {Humans ; *Rhinitis/diagnosis/therapy/pathology ; *Nasal Polyps/pathology ; Nasal Mucosa/pathology ; *Communicable Diseases/pathology ; Chronic Disease ; Biofilms ; }, abstract = {BACKGROUD: Biofilm formation has been recently recognised as one of the most important etiopathological mechanisms underlying chronic rhinosinusitis (CRS) and its recalcitrance. In this context, nasal cytology (NC) has become an integral part of diagnostic work up of patients suffering from sino-nasal diseases, since it is an easy-to-apply, reproducible and non-invasive diagnostic tool that allows to assess both the nasal inflammatory infiltrate and the presence of biofilms on nasal mucosal surface, further orienting the therapeutic choices in case of infectious diseases for eradicating infections and biofilms. Nevertheless, biofilms are typically resistant to common antibiotic treatments and may trigger or maintain chronic inflammation. Hence, the importance of correctly detecting the presence of biofilm and identifying new effective treatments.

PURPOSE: The aim of this brief review is to better clarify the role of biofilm in the pathogenesis and recurrence of sino-nasal disorders and to highlight the role of nasal cytology (NC) in the rhino-allergologic diagnostic path and in the evaluation of the effectiveness of new treatments.}, } @article {pmid36375381, year = {2022}, author = {Gu, Y and Lu, H and Shao, Y and Fu, D and Wu, J and Hu, J and Tu, J and Song, X and Qi, K}, title = {Acetoacetyl-CoA transferase ydiF regulates the biofilm formation of avian pathogenic Escherichia coli.}, journal = {Research in veterinary science}, volume = {153}, number = {}, pages = {144-152}, doi = {10.1016/j.rvsc.2022.10.016}, pmid = {36375381}, issn = {1532-2661}, abstract = {Avian pathogenic Escherichia coli (APEC) causes persistent infection of poultry and multi-system diseases, which seriously endanger the development of the poultry industry. Biofilm allows bacteria to adapt to the natural environment and plays an important role in resistance to the external environment and the pathogenicity of APEC, but the mechanism of its formation and regulatory network have not been clarified. In this study, we used a Tn5 transposon random mutation library constructed with APEC and identified ydiF, a gene that has not previously been recognized in E. coli biofilm formation. To confirm that the ydiF gene really can regulate the formation of APEC biofilm, the ydiF gene deletion strain was constructed using APEC81. Protein association networks prediction results show that ydiF is mainly associated with genes related to the metabolism of sugars and fatty acids. Deletion of the ydiF gene significantly reduces the formation of APEC biofilm and scanning electron microscopy indicated that the degree of adhesion between the bacteria was also reduced. The deletion of the ydiF gene also significantly reduced the motility of APEC81 and through transmission electron microscopy APEC81 was observed to have significantly fewer flagella. However, the colony morphology of APEC81 on Congo red and Coomassie brilliant blue media was unaffected. The results of fluorescence quantification showed that the deletion of the ydiF gene caused a down-regulation in the transcription of genes related to the second messenger, sugar metabolism, and quorum sensing. These results indicate that ydiF plays an important role in biofilm formation and the movement of APEC. In addition, it may be possible to regulate the formation of APEC biofilms by different methods such as by regulating the second messenger and metabolic system.}, } @article {pmid36374078, year = {2022}, author = {Piazza, A and Parra, L and Ciancio Casalini, L and Sisti, F and Fernández, J and Malone, JG and Ottado, J and Serra, DO and Gottig, N}, title = {Cyclic di-GMP Signaling Links Biofilm Formation and Mn(II) Oxidation in Pseudomonas resinovorans.}, journal = {mBio}, volume = {13}, number = {6}, pages = {e0273422}, pmid = {36374078}, issn = {2150-7511}, mesh = {Humans ; *Proteomics ; *Pseudomonas/metabolism ; Cyclic GMP/metabolism ; Oxidation-Reduction ; Biofilms ; Bacteria/metabolism ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Bioaugmentation of biological sand filters with Mn(II)-oxidizing bacteria (MOB) is used to increase the efficiency of Mn removal from groundwater. While the biofilm-forming ability of MOB is important to achieve optimal Mn filtration, the regulatory link between biofilm formation and Mn(II) oxidation remains unclear. Here, an environmental isolate of Pseudomonas resinovorans strain MOB-513 was used as a model to investigate the role of c-di-GMP, a second messenger crucially involved in the regulation of biofilm formation by Pseudomonas, in the oxidation of Mn(II). A novel role for c-di-GMP in the upregulation of Mn(II) oxidation through induction of the expression of manganese-oxidizing peroxidase enzymes was revealed. MOB-513 macrocolony biofilms showed a strikingly stratified pattern of biogenic Mn oxide (BMnOx) accumulation in a localized top layer. Remarkably, elevated cellular levels of c-di-GMP correlated not only with increased accumulation of BMnOx in the same top layer but also with the appearance of a second BMnOx stratum in the bottom region of macrocolony biofilms, and the expression of mop genes correlated with this pattern. Proteomic analysis under Mn(II) conditions revealed changes in the abundance of a PilZ domain protein. Subsequent analyses supported a model in which this protein sensed c-di-GMP and affected a regulatory cascade that ultimately inhibited mop gene expression, providing a molecular link between c-di-GMP signaling and Mn(II) oxidation. Finally, we observed that high c-di-GMP levels were correlated with higher lyophilization efficiencies and higher groundwater Mn(II) oxidation capacities of freeze-dried bacterial cells, named lyophiles, showing the biotechnological relevance of understanding the role of c-di-GMP in MOB-513. IMPORTANCE The presence of Mn(II) in groundwater, a common source of drinking water, is a cause of water quality impairment, interfering with its disinfection, causing operation problems, and affecting human health. Purification of groundwater containing Mn(II) plays an important role in environmental and social safety. The typical method for Mn(II) removal is based on bacterial oxidation of metals to form insoluble oxides that can be filtered out of the water. Evidence of reducing the start-up periods and enhancing Mn removal efficiencies through bioaugmentation with appropriate biofilm-forming and MOB has emerged. As preliminary data suggest a link between these two phenotypes in Pseudomonas strains, the need to investigate the underlying regulatory mechanisms is apparent. The significance of our research lies in determining the role of c-di-GMP for increased biofilm formation and Mn(II)-oxidizing capabilities in MOB, which will allow the generation of super-biofilm-elaborating and Mn-oxidizing strains, enabling their implementation in biotechnological applications.}, } @article {pmid36372480, year = {2023}, author = {Wang, X and Zhang, X and Wang, Y and Tang, N and Xiao, L and Tian, J and Rui, X and Li, W}, title = {Yeast cell wall polysaccharides in Tibetan kefir grains are key substances promoting the formation of bacterial biofilm.}, journal = {Carbohydrate polymers}, volume = {300}, number = {}, pages = {120247}, doi = {10.1016/j.carbpol.2022.120247}, pmid = {36372480}, issn = {1879-1344}, mesh = {*Kefir/microbiology ; Tibet ; Yeasts ; Bacteria ; Biofilms ; Cell Wall ; Polysaccharides/pharmacology ; Polysaccharides, Bacterial/pharmacology ; }, abstract = {This study investigated the interaction among Kluyveromyces marxianus G-Y4 (G-Y4), Lacticaseibacillus paracasei GL1 (GL1) and Lactobacillus helveticus SNA12 (SNA12) that isolated from Tibetan kefir grains. Additionally, the effects of G-Y4 on the growth and biofilm formation of GL1 and SNA12 were determined. The results indicated that G-Y4 promoted the growth of GL1 and SNA12 and improved their biofilm-forming ability. Furthermore, the dead cells of G-Y4 were found that could enhance bacterial biofilm formation, and the cell wall polysaccharide (CWPS) produced by G-Y4 was performed to be key substances that promote the formation of bacterial biofilms. Moreover, the structure of soluble cell wall polysaccharides (SCWP) and insoluble cell wall polysaccharide (NCWP) of G-Y4 were studied to determine their contribution to biofilm formation. Results showed that G-Y4-SCWP was α-mannan with the main chain of a →6)-α-d-Manp-(1→ unit and the branch structure of →2)-α-d-Manp-(1. At the same time, G-Y4-NCWP was a glucan rich in β-(1→3), β-(1→2), or β-(1→4) linkages.}, } @article {pmid36371999, year = {2023}, author = {Park, H and Kim, J and Kim, H and Cho, E and Park, H and Jeon, B and Ryu, S}, title = {Characterization of the lytic phage MSP1 for the inhibition of multidrug-resistant Salmonella enterica serovars Thompson and its biofilm.}, journal = {International journal of food microbiology}, volume = {385}, number = {}, pages = {110010}, doi = {10.1016/j.ijfoodmicro.2022.110010}, pmid = {36371999}, issn = {1879-3460}, mesh = {Animals ; Serogroup ; Merozoite Surface Protein 1 ; *Bacteriophages ; Biofilms ; Salmonella typhimurium ; *Salmonella enterica ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The increasing prevalence of multidrug-resistant (MDR) Salmonella is a serious public health threat. Intervention strategies available to control Salmonella mostly target Salmonella enterica serovars Typhimurium and Enteritidis, and little has been investigated to control serovars in serogroup C, such as S. enterica serovar Thompson, despite their increasing prevalence. Here, we isolated phages targeting MDR S. Thompson and characterized the antimicrobial activities of MSP1 phage, a virulent phage with a broad host range. MSP1 phage strongly infected S. Thompson and S. Mbandaka isolates from retail chicken and also other serovars, including Dublin, Enteritidis, Heidelberg, Paratyphi, and Typhimurium. MSP1 phage was able to inhibit the biofilm formation on stainless steel and glass formation by around 42.7-47.9 %. MSP1 phage was robust to withstand wide ranges of pH (4-12) and temperature (30-60 °C), and no genes associated with antibiotic resistance and virulence were found in the phage genome, suggesting that this phage is suitable for food application. When MSP1 phage was tested on foods (chicken meat and milk), MSP1 phage significantly reduced the level of MDR S. Thompson below the detection limit. Our findings suggest that MSP1 phage is a promising antimicrobial agent for the control of food contamination by MDR S. Thompson.}, } @article {pmid36370776, year = {2023}, author = {Dinesh, R and Sreena, CP and Sheeja, TE and Charles, S and Srinivasan, V and Sajith, V and Subila, KP and Haritha, P}, title = {Metagenomics indicates abundance of biofilm related genes and horizontal transfer of multidrug resistant genes among bacterial communities in nano zinc oxide polluted soil.}, journal = {The Science of the total environment}, volume = {859}, number = {Pt 1}, pages = {160032}, doi = {10.1016/j.scitotenv.2022.160032}, pmid = {36370776}, issn = {1879-1026}, mesh = {*Zinc Oxide/toxicity ; Soil ; *Nanoparticles ; Biofilms ; *Metal Nanoparticles/toxicity ; Oxides ; }, abstract = {The unsafe and reckless disposal of metal oxide nanoparticles like ZnO (nZnO) into the soil could seriously impact bacterial behavioural responses and functions. Under such stress, biofilm formation is considered to be a robust mechanism for bacterial survival in soil. We examined the response of bacterial metagenomes in soils exposed to varying levels of Zn (50, 200, 500 and 1000 mg kg[-1]) as nano Zn oxide (nZnO) in terms of biofilm genesis and regulation and their co-occurrences with multidrug resistance genes (MDRGs) and mobile genetic elements (MGEs). The size-specific effects of nZnO were verified using its bulk counterpart (bZnO). Both nZnO and bZnO facilitated profusion of biofilm related genes (BGs) especially at higher Zn levels (500 and 1000 mg kg[-1] Zn), though maximum abundance was registered at a comparatively lower level under nZnO. In general, nZnO favoured an enhancement of genes involved in exopolysaccharide biosynthesis and attachment, while bZnO favoured genes related to capsule formation, chemotaxis and biofilm dispersion. Co-occurrence network analysis revealed significant positive correlations between abundances of BGs, MDRGs and MGEs, indicating an enhanced probability for horizontal gene transfer of MDRGs in nZnO polluted soils.}, } @article {pmid36370527, year = {2023}, author = {Wang, D and Fletcher, GC and On, SLW and Palmer, JS and Gagic, D and Flint, SH}, title = {Biofilm formation, sodium hypochlorite susceptibility and genetic diversity of Vibrio parahaemolyticus.}, journal = {International journal of food microbiology}, volume = {385}, number = {}, pages = {110011}, doi = {10.1016/j.ijfoodmicro.2022.110011}, pmid = {36370527}, issn = {1879-3460}, mesh = {*Vibrio parahaemolyticus/genetics ; Sodium Hypochlorite/pharmacology ; Multilocus Sequence Typing ; Biofilms ; Genetic Variation ; }, abstract = {Vibrio parahaemolyticus is a marine oriented pathogen; and biofilm formation enables its survival and persistence on seafood processing plant, complicating the hygienic practice. The objectives of this study are to assess the ability of V. parahaemolyticus isolated from seafood related environments to form biofilms, to determine the effective sodium hypochlorite concentrations required to inactivate planktonic and biofilm cells, and to evaluate the genetic diversity required for strong biofilm formation. Among nine isolates, PFR30J09 and PFR34B02 isolates were identified as strong biofilm forming strains, with biofilm cell counts of 7.20, 7.08 log10 CFU/cm[2], respectively, on stainless steel coupons after incubation at 25 °C. Free available chlorine of 1176 mg/L and 4704 mg/L was required to eliminate biofilm cells of 1.74-2.28 log10 CFU/cm[2] and > 7 log10 CFU/cm[2], respectively, whereas 63 mg/L for planktonic cells, indicating the ineffectiveness of sodium hypochlorite in eliminating V. parahaemolyticus biofilm cells at recommended concentration in the food industry. These strong biofilm-forming isolates produced more polysaccharides and were less susceptible to sodium hypochlorite, implying a possible correlation between polysaccharide production and sodium hypochlorite susceptibility. Genetic diversity in mshA, mshC and mshD contributed to the observed variation in biofilm formation between isolates. This study identified strong biofilm-forming V. parahaemolyticus strains of new multilocus sequence typing (MLST) types, showed a relationship between polysaccharide production and sodium hypochlorite resistance.}, } @article {pmid36367548, year = {2022}, author = {Wang, M and Zhan, X and Ma, X and Wang, R and Guo, D and Zhang, Y and Yu, J and Chang, Y and Lü, X and Shi, C}, title = {Antibacterial Activity of Thymoquinone Against Shigella flexneri and Its Effect on Biofilm Formation.}, journal = {Foodborne pathogens and disease}, volume = {19}, number = {11}, pages = {767-778}, doi = {10.1089/fpd.2022.0056}, pmid = {36367548}, issn = {1556-7125}, mesh = {*Shigella flexneri ; *Benzoquinones/pharmacology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Thymoquinone (TQ) has been demonstrated to have anti-cancer, anti-inflammatory, antioxidant, and anti-diabetic activities. Shigella flexneri is the main pathogen causing shigellosis in developing countries. In this study, the antibacterial activity of TQ against S. flexneri and its possible antibacterial mechanism were studied. In addition, the inhibitory effect of TQ on the formation of S. flexneri biofilm was also investigated. The results showed that both the minimum inhibitory concentration and the minimum bactericidal concentration of TQ against S. flexneri ATCC 12022 were 0.2 mg/mL. After treatment with TQ at 0.4 mg/mL in Luria-Bertani broth for 3 h, or treatment with 0.2 mg/mL TQ in phosphate-buffered saline for 60 min, the number of S. flexneri (initial number is 6.5 log colony-forming units/mL) dropped below the detection limit. TQ also displayed good antibacterial activity in contaminated lettuce juice. TQ caused an increase in intracellular reactive oxygen species level, a decrease in intracellular adenosine triphosphate (ATP) concentration, a change in the intracellular protein, damage to cell membrane integrity and changes in cell morphology. In addition, TQ showed the ability to inhibit the formation of S. flexneri biofilm; treatment resulted in a decrease in the amount of biofilm and extracellular polysaccharides, and the destruction of biofilm structure. These findings indicated that TQ had strong antimicrobial and antibiofilm activities and a potential to be applied in the fruit and vegetable processing industry or other food industries to control S. flexneri.}, } @article {pmid36364415, year = {2022}, author = {Pernas-Pleite, C and Conejo-Martínez, AM and Marín, I and Abad, JP}, title = {Green Extracellular Synthesis of Silver Nanoparticles by Pseudomonas alloputida, Their Growth and Biofilm-Formation Inhibitory Activities and Synergic Behavior with Three Classical Antibiotics.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {21}, pages = {}, pmid = {36364415}, issn = {1420-3049}, support = {PID2019-104812GB-100//Ministerio de Ciencia e Investigación/ ; }, mesh = {*Anti-Bacterial Agents/chemistry ; Silver/pharmacology/chemistry ; Staphylococcus aureus ; *Metal Nanoparticles/chemistry ; Escherichia coli ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Bacillus subtilis ; Biofilms ; Ampicillin/pharmacology ; Streptomycin/pharmacology ; Plant Extracts/chemistry ; }, abstract = {Bacterial resistance to antibiotics is on the rise and hinders the fight against bacterial infections, which are expected to cause millions of deaths by 2050. New antibiotics are difficult to find, so alternatives are needed. One could be metal-based drugs, such as silver nanoparticles (AgNPs). In general, chemical methods for AgNPs' production are potentially toxic, and the physical ones expensive, while green approaches are not. In this paper, we present the green synthesis of AgNPs using two Pseudomonas alloputida B003 UAM culture broths, sampled from their exponential and stationary growth phases. AgNPs were physicochemically characterized by transmission electron microscopy (TEM), total reflection X-ray fluorescence (TXRF), infrared spectroscopy (FTIR), dynamic light scattering (DLS), and X-ray diffraction (XRD), showing differential characteristics depending on the synthesis method used. Antibacterial activity was tested in three assays, and we compared the growth and biofilm-formation inhibition of six test bacteria: Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. We also monitored nanoparticles' synergic behavior through the growth inhibition of E. coli and S. aureus by three classical antibiotics: ampicillin, nalidixic acid, and streptomycin. The results indicate that very good AgNP activity was obtained with particularly low MICs for the three tested strains of P. aeruginosa. A good synergistic effect on streptomycin activity was observed for all the nanoparticles. For ampicillin, a synergic effect was detected only against S. aureus. ROS production was found to be related to the AgNPs' antibacterial activity.}, } @article {pmid36364371, year = {2022}, author = {Patra, A and Das, J and Agrawal, NR and Kushwaha, GS and Ghosh, M and Son, YO}, title = {Marine Antimicrobial Peptides-Based Strategies for Tackling Bacterial Biofilm and Biofouling Challenges.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {21}, pages = {}, pmid = {36364371}, issn = {1420-3049}, support = {ICMR/BMI/11(45)/2020//Indian Council of Medical Research/ ; 2022H1D3A2A02053110//National Research Foundation of Korea/ ; }, mesh = {Animals ; *Antimicrobial Peptides ; *Biofouling/prevention & control ; Biofilms ; Bacteria ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {An assemblage nexus of microorganisms enclosed in a composite extracellular polymeric matrix is called as a biofilm. The main factor causing biological fouling, or biofouling, is biofilms. Biofilm-mediated biofouling is a significant detrimental issue in several industries, including the maritime environment, industrial facilities, water treatment facilities, and medical implants. Conventional antibacterial remedies cannot wholly eradicate bacterial species owing to the structural rigidity of biofilm and the eventual growth of antibiotic-resistant microorganisms. Consequently, several approaches to disrupt the biofilm have been investigated to address this particular phenomenon. Antimicrobial peptides (AMPs) have emerged as a promising contender in this category, offering several advantages over traditional solutions, including broad-spectrum action and lack of antibiotic resistance. Because biofouling significantly impacts the marine industry, AMPs derived from marine sources may be suitable natural inhibitors of bacterial proliferation. In this article, we discuss the range of physicochemical and structural diversity and the model of action seen in marine AMPs. This makes them an appealing strategy to mitigate biofilm and biofilm-mediated biofouling. This review also systematically summarizes recent research on marine AMPs from vertebrates and invertebrates and their industrial significance, shedding light on developing even better anti-biofouling materials shortly.}, } @article {pmid36364211, year = {2022}, author = {Wultańska, D and Paterczyk, B and Nowakowska, J and Pituch, H}, title = {The Effect of Selected Bee Products on Adhesion and Biofilm of Clostridioides difficile Strains Belonging to Different Ribotypes.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {21}, pages = {}, pmid = {36364211}, issn = {1420-3049}, support = {WUM/UW-1M20/NUW1/19//Medical University of Warsaw/ ; }, mesh = {Bees ; Animals ; Ribotyping ; *Clostridioides difficile ; Clostridioides ; *Propolis/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; *Honey ; Anti-Bacterial Agents/pharmacology/therapeutic use ; }, abstract = {There is an ongoing search for alternative treatments for Clostridioides difficile infections. The aim of the study was to investigate the antibacterial and antibiotic activity of bee products against C. difficile strains with different polymerase chain reaction ribotypes (RTs). The minimum inhibitory concentration (MICs) of Manuka honey 550+, goldenrod honey, pine honey, and bee bread were determined by the broth dilution method. C. difficile adhesion to HT-29, HT-29 MTX, and CCD 841 CoN cell lines was assessed. Biofilm was cultured in titration plates and visualized by confocal microscopy. The MICs of Manuka honey for C. difficile 630 and ATCC 9689 strains and control strain, M 120, were 6.25%, 6.25%, and 1.56% (v/v), respectively; of goldenrod honey, 50%, 50%, and 12.5%, respectively; of pine honey, 25%, 25%, and 25%, respectively; and of bee bread, 100 mg/L, 50 mg/L, and 100 mg/L, respectively. Manuka honey (1%) increased adhesion of C. difficile RT176 strains, and one strain of RT023, to the CCD 841 cell line. Pine honey (1%) increased RT027 adhesion to the HT-29 cell line. Manuka honey, pine honey, and bee bread at subinhibitory concentrations increased the adhesion of C. difficile. Our research proved that bee products are active against the tested strains of C. difficile.}, } @article {pmid36363771, year = {2022}, author = {Eshima, S and Kurakado, S and Matsumoto, Y and Kudo, T and Sugita, T}, title = {Candida albicans Promotes the Antimicrobial Tolerance of Escherichia coli in a Cross-Kingdom Dual-Species Biofilm.}, journal = {Microorganisms}, volume = {10}, number = {11}, pages = {}, pmid = {36363771}, issn = {2076-2607}, support = {JP20fk0108135h0201//Japan Agency for Medical Research and Development/ ; }, abstract = {Cross-kingdom multi-species biofilms consisting of fungi and bacteria are often resistant to antimicrobial treatment, leading to persistent infections. We evaluated whether the presence of Candida albicans affects the antibacterial tolerance of Escherichia coli in dual-species biofilms and explored the underlying mechanism. We found that the survival of E. coli in the presence of antibacterial drugs was higher in dual-species biofilms compared to single-species biofilms. This tolerance-inducing effect was observed in E. coli biofilms that were treated with a C. albicans culture supernatant. To explore the antibacterial tolerance-inducing factor contained in the culture supernatant and identify the tolerance mechanism, a heated supernatant, a supernatant treated with lyticase, DNase, and proteinase K, or a supernatant added to a drug efflux pump inhibitor were used. However, the tolerance-inducing activity was not lost, indicating the existence of some other mechanisms. Ultrafiltration revealed that the material responsible for tolerance-inducing activity was <10 kDa in size. This factor has not yet been identified and needs further studies to understand the mechanisms of action of this small molecule precisely. Nevertheless, we provide experimental evidence that Candida culture supernatant induces E. coli antibacterial tolerance in biofilms. These findings will guide the development of new treatments for dual-species biofilm infections.}, } @article {pmid36363757, year = {2022}, author = {Pokhrel, D and Thames, HT and Zhang, L and Dinh, TTN and Schilling, W and White, SB and Ramachandran, R and Theradiyil Sukumaran, A}, title = {Roles of Aerotolerance, Biofilm Formation, and Viable but Non-Culturable State in the Survival of Campylobacter jejuni in Poultry Processing Environments.}, journal = {Microorganisms}, volume = {10}, number = {11}, pages = {}, pmid = {36363757}, issn = {2076-2607}, abstract = {Campylobacter jejuni is one of the most common causes of foodborne human gastroenteritis in the developed world. This bacterium colonizes in the ceca of chickens, spreads throughout the poultry production chain, and contaminates poultry products. Despite numerous on farm intervention strategies and developments in post-harvest antimicrobial treatments, C. jejuni is frequently detected on broiler meat products. This indicates that C. jejuni is evolving over time to overcome the stresses/interventions that are present throughout poultry production and processing. The development of aerotolerance has been reported to be a major survival strategy used by C. jejuni in high oxygen environments. Recent studies have indicated that C. jejuni can enter a viable but non-culturable (VBNC) state or develop biofilm in response to environmental stressors such as refrigeration and freezing stress and aerobic stress. This review provides an overview of different stressors that C. jejuni are exposed to throughout the poultry production chain and the genotypic and phenotypic survival mechanisms, with special attention to aerotolerance, biofilm formation, and development of the VBNC state.}, } @article {pmid36363697, year = {2022}, author = {Islam, S and Mahmud, ML and Almalki, WH and Biswas, S and Islam, MA and Mortuza, MG and Hossain, MA and Ekram, MA and Uddin, MS and Zaman, S and Saleh, MA}, title = {Cell-Free Supernatants (CFSs) from the Culture of Bacillus subtilis Inhibit Pseudomonas sp. Biofilm Formation.}, journal = {Microorganisms}, volume = {10}, number = {11}, pages = {}, pmid = {36363697}, issn = {2076-2607}, abstract = {Biofilm inhibition has been identified as a novel drug target for the development of broad-spectrum antibiotics to combat infections caused by drug-resistant bacteria. Although several plant-based compounds have been reported to have anti-biofilm properties, research on the anti-biofilm properties of bacterial bioactive compounds has been sparse. In this study, the efficacy of compounds from a cell-free supernatant of Bacillus subtilis against a biofilm formation of Pseudomonas sp. was studied through in vitro, in vivo and in silico studies. Here, in well diffusion method, Bacillus subtilis demonstrated antibacterial activity, and more than 50% biofilm inhibition activity against Pseudomonas sp. was exhibited through in vitro studies. Moreover, molecular docking and molecular dynamics (MD) simulation gave insights into the possible mode of action of the bacterial volatile compounds identified through GC-MS to inhibit the biofilm-formation protein (PDB ID: 7M1M) of Pseudomonas sp. The binding energy revealed from docking studies ranged from -2.3 to -7.0 kcal mol[-1]. Moreover, 1-(9H-Fluoren-2-yl)-2-(1-phenyl-1H-ttetrazole5-ylsulfanyl)-ethanone was found to be the best-docked compound through ADMET and pharmacokinetic properties. Furthermore, MD simulations further supported the in vitro studies and formed a stable complex with the tested protein. Thus, this study gives an insight into the development of new antibiotics to combat multi-drug-resistant bacteria.}, } @article {pmid36363467, year = {2022}, author = {Ahmad, S and Rahman, H and Qasim, M and Nawab, J and Alzahrani, KJ and Alsharif, KF and Alzahrani, FM}, title = {Staphylococcus epidermidis Pathogenesis: Interplay of icaADBC Operon and MSCRAMMs in Biofilm Formation of Isolates from Pediatric Bacteremia in Peshawar, Pakistan.}, journal = {Medicina (Kaunas, Lithuania)}, volume = {58}, number = {11}, pages = {}, pmid = {36363467}, issn = {1648-9144}, mesh = {Humans ; Child ; Staphylococcus epidermidis/genetics ; Pakistan ; Operon/genetics ; *Bacteremia ; Biofilms ; Polysaccharides ; *Staphylococcal Infections ; }, abstract = {Background and Objective: Staphylococcus epidermidis is an opportunistic pathogen from pediatric bacteremia that is commonly isolated. Biofilm is the major virulence factor of S. epidermidis; however, the role of biofilm determinants in biofilm formation is highly contradictory and diverse. The current study aimed to investigate the role of polysaccharide-dependent and polysaccharide-independent pathogenic determinants in biofilm formation under physiological stress conditions. Materials and Methods: The isolates (n = 75) were identified and screened for the icaADBC operon, IS256, and an array of MSCRAMMs (Microbial Surface Component Recognizing Adhesive Matrix Molecules) through PCR analysis. The activity of the icaADBC operon was detected by Congo red assay, and the biofilm formation was analyzed through microtiter plate assay. Results: S. epidermidis isolates produced biofilm (n = 65; 86.6%) frequently. The icaA was the major representative module of the actively expressing icaADBC operon (n = 21; 80.7% sensitivity). The MSCRAMMs, including fbe (n = 59; 90.7%; p = 0.007), and embp (n = 57; 87.6%; p = 0.026), were highly prevalent and associated with biofilm positive S. epidermidis. The prevalence of icaADBC operon in biofilm positive and negative S. epidermidis was not significant (n = 41; 63%; p = 0.429). No significant association was found between IS256 and actively complete icaADBC operon (n = 10; 47.6%; p = 0.294). In the presence of 5% human plasma and glucose stress, S. epidermidis produced a strong biofilm (n = 55; 84.6%). Conclusion: The polysaccharide-dependent biofilm formation is significantly replaced (n = 21; 28%; p = 0.149) by a polysaccharide-independent mechanism (n = 59; 90.7%; p = 0.007), in which the MSCRAMMs might actively play their role. The fibrinogen-binding protein and extracellular matrix-binding protein might be potential anti-biofilm drug targets, markers of rapid diagnosis, and potential vaccine candidates of S. epidermidis involved in pediatric bacteremia.}, } @article {pmid36362840, year = {2022}, author = {Pereira, ACC and Aguiar, APS and Araujo, LMP and Dantas, LO and Mayer, MPA and Karygianni, L and Thurnheer, T and Pinheiro, ET}, title = {Antibiofilm Activity of LL-37 Peptide and D-Amino Acids Associated with Antibiotics Used in Regenerative Endodontics on an Ex Vivo Multispecies Biofilm Model.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {11}, pages = {}, pmid = {36362840}, issn = {2075-1729}, support = {2019/12908-3//São Paulo Research Foundation/ ; 163086/2021-4//National Council for Scientific and Technological Development/ ; }, abstract = {The antimicrobial peptide LL-37 and D-amino acids (D-AAs) have been proposed as antibiofilm agents. Therefore, this study aimed to test the antimicrobial effect of antibiofilm agents associated with antibiotics used in regenerative endodontic procedures (the triple antibiotic paste—TAP: ciprofloxacin + metronidazole + minocycline). An endodontic-like biofilm model grown on bovine dentin discs was used in this study. After 21-day growth, the biofilms were treated with 1 mg/mL TAP, 10 μM LL-37, an association of LL-37 + TAP, 40 mM D-AAs solution, an association of D-AAs + TAP, and phosphate-buffered saline (negative control). Colony forming unit (CFU) data were analyzed by two-way ANOVA and Tukey’s multiple comparison test (p < 0.05). LL-37 + TAP showed the best antibacterial activity (7-log10 CFU/mL ± 0.5), reaching a 1 log reduction of cells in relation to the negative control (8-log10 CFU/mL ± 0.7) (p < 0.05). In turn, no significant reduction in bacterial cells was observed with TAP, LL-37, D-AAs, and D-AAs + TAP compared to the negative control. In conclusion, the combination of antibiotics and LL-37 peptide showed mild antibacterial activity, while the combination of antibiotics and D-AAs showed no activity against complex biofilms.}, } @article {pmid36362310, year = {2022}, author = {Krasowski, G and Migdał, P and Woroszyło, M and Fijałkowski, K and Chodaczek, G and Czajkowska, J and Dudek, B and Nowicka, J and Oleksy-Wawrzyniak, M and Kwiek, B and Paleczny, J and Brożyna, M and Junka, A}, title = {The Assessment of Activity of Antiseptic Agents against Biofilm of Staphylococcus aureus Measured with the Use of Processed Microscopic Images.}, journal = {International journal of molecular sciences}, volume = {23}, number = {21}, pages = {}, pmid = {36362310}, issn = {1422-0067}, support = {2017/27/B/NZ6/02103//National Science Center/ ; }, mesh = {Humans ; Staphylococcus aureus ; Povidone-Iodine/pharmacology ; Hypochlorous Acid ; *Anti-Infective Agents, Local/pharmacology ; Biofilms ; *Staphylococcal Infections/drug therapy ; Anti-Bacterial Agents/therapeutic use ; }, abstract = {Staphylococcal biofilms are major causative factors of non-healing wound infections. Their treatment algorithms recommend the use of locally applied antiseptic agents to counteract the spread of infection. The efficacy of antiseptics against biofilm is assessed in vitro by a set of standard quantitative and semi-quantitative methods. The development of software for image processing additionally allowed for the obtainment of quantitative data from microscopic images of biofilm dyed with propidium iodine and SYTO-9 reagents, differentiating dead cells from live ones. In this work, the method of assessment of the impact of antiseptic agents on staphylococcal biofilm in vitro, based on biofilms' processed images, was proposed and scrutinized with regard to clinically relevant antiseptics, polyhexanide, povidone-iodine and hypochlorite. The standard quantitative culturing method was applied to validate the obtained data from processed images. The results indicated significantly higher activity of polyhexanide and povidone-iodine than hypochlorite against staphylococcal biofilm. Taking into account the fact that in vitro results of the efficacy of antiseptic agents against staphylococcal biofilm are frequently applied to back up their use in hospitals and ambulatory units, our work should be considered an important tool; providing reliable, quantitative data in this regard.}, } @article {pmid36362111, year = {2022}, author = {Jiang, M and Chen, R and Zhang, J and Chen, F and Wang, KJ}, title = {A Novel Antimicrobial Peptide Spampcin56-86 from Scylla paramamosain Exerting Rapid Bactericidal and Anti-Biofilm Activity In Vitro and Anti-Infection In Vivo.}, journal = {International journal of molecular sciences}, volume = {23}, number = {21}, pages = {}, pmid = {36362111}, issn = {1422-0067}, support = {2021J05008//National Natural Science Foundation of Fujian Province/ ; U1805233//National Natural Science Foundation of China/ ; 20CZP011HJ06//Xiamen Ocean and Fishery Development Special Fund Project/ ; 3502Z20203012//Xiamen Science and Technology Planning Project/ ; }, mesh = {Animals ; Humans ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Antimicrobial Cationic Peptides/chemistry ; Antimicrobial Peptides ; Bacteria/metabolism ; *Brachyura/metabolism ; Microbial Sensitivity Tests ; Zebrafish/metabolism ; }, abstract = {The abuse of antibiotics leads to the increase of bacterial resistance, which seriously threatens human health. Therefore, there is an urgent need to find effective alternatives to antibiotics, and antimicrobial peptides (AMPs) are the most promising antibacterial agents and have received extensive attention. In this study, a novel potential AMP was identified from the marine invertebrate Scylla paramamosain and named Spampcin. After bioinformatics analysis and AMP database prediction, four truncated peptides (Spa31, Spa22, Spa20 and Spa14) derived from Spampcin were screened, all of which showed potent antimicrobial activity with different antibacterial spectrum. Among them, Spampcin56-86 (Spa31 for short) exhibited strong bactericidal activity against a variety of clinical pathogens and could rapidly kill the tested bacteria within minutes. Further analysis of the antibacterial mechanism revealed that Spa31 disrupted the integrity of the bacterial membrane (as confirmed by scanning electron microscopy observation, NPN, and PI staining assays), leading to bacterial rupture, leakage of cellular contents (such as elevated extracellular ATP), increased ROS production, and ultimately cell death. Furthermore, Spa31 was found to interact with LPS and effectively inhibit bacterial biofilms. The antibacterial activity of Spa31 had good thermal stability, certain ion tolerance, and no obvious cytotoxicity. It is worth noting that Spa31 could significantly improve the survival rate of zebrafish Danio rerio infected with Pseudomonas aeruginosa, indicating that Spa31 played an important role in anti-infection in vivo. This study will enrich the database of marine animal AMPs and provide theoretical reference and scientific basis for the application of marine AMPs in medical fields.}, } @article {pmid36361877, year = {2022}, author = {Cavalu, S and Elbaramawi, SS and Eissa, AG and Radwan, MF and S Ibrahim, T and Khafagy, ES and Lopes, BS and Ali, MAM and Hegazy, WAH and Elfaky, MA}, title = {Characterization of the Anti-Biofilm and Anti-Quorum Sensing Activities of the β-Adrenoreceptor Antagonist Atenolol against Gram-Negative Bacterial Pathogens.}, journal = {International journal of molecular sciences}, volume = {23}, number = {21}, pages = {}, pmid = {36361877}, issn = {1422-0067}, mesh = {Mice ; Animals ; *Atenolol/pharmacology/metabolism ; *Virulence Factors/genetics ; Quorum Sensing ; Biofilms ; Gram-Negative Bacteria ; Pseudomonas aeruginosa ; Serratia marcescens/metabolism ; Anti-Bacterial Agents/pharmacology/metabolism ; Proteus mirabilis/metabolism ; Bacterial Proteins/metabolism ; }, abstract = {The development of bacterial resistance to antibiotics is an increasing public health issue that worsens with the formation of biofilms. Quorum sensing (QS) orchestrates the bacterial virulence and controls the formation of biofilm. Targeting bacterial virulence is promising approach to overcome the resistance increment to antibiotics. In a previous detailed in silico study, the anti-QS activities of twenty-two β-adrenoreceptor blockers were screened supposing atenolol as a promising candidate. The current study aims to evaluate the anti-QS, anti-biofilm and anti-virulence activities of the β-adrenoreceptor blocker atenolol against Gram-negative bacteria Serratia marcescens, Pseudomonas aeruginosa, and Proteus mirabilis. An in silico study was conducted to evaluate the binding affinity of atenolol to S. marcescens SmaR QS receptor, P. aeruginosa QscR QS receptor, and P. mirabilis MrpH adhesin. The atenolol anti-virulence activity was evaluated against the tested strains in vitro and in vivo. The present finding shows considerable ability of atenolol to compete with QS proteins and significantly downregulated the expression of QS- and virulence-encoding genes. Atenolol showed significant reduction in the tested bacterial biofilm formation, virulence enzyme production, and motility. Furthermore, atenolol significantly diminished the bacterial capacity for killing and protected mice. In conclusion, atenolol has potential anti-QS and anti-virulence activities against S. marcescens, P. aeruginosa, and P. mirabilis and can be used as an adjuvant in treatment of aggressive bacterial infections.}, } @article {pmid36361021, year = {2022}, author = {Colombari, B and Tagliazucchi, D and Odorici, A and Pericolini, E and Foltran, I and Pinetti, D and Meto, A and Peppoloni, S and Blasi, E}, title = {Pomegranate Extract Affects Fungal Biofilm Production: Consumption of Phenolic Compounds and Alteration of Fungal Autoinducers Release.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {21}, pages = {}, pmid = {36361021}, issn = {1660-4601}, mesh = {*Farnesol/pharmacology ; *Pomegranate ; Biofilms ; Candida albicans ; Antifungal Agents/pharmacology ; Plant Extracts/pharmacology ; }, abstract = {Candida albicans expresses numerous virulence factors that contribute to pathogenesis, including its dimorphic transition and even biofilm formation, through the release of specific quorum sensing molecules, such as the autoinducers (AI) tyrosol and farnesol. In particular, once organized as biofilm, Candida cells can elude conventional antifungal therapies and the host's immune defenses as well. Accordingly, biofilm-associated infections become a major clinical challenge underlining the need of innovative antimicrobial approaches. The aim of this in vitro study was to assess the effects of pomegranate peel extract (PomeGr) on C. albicans growth and biofilm formation; in addition, the release of tyrosol and farnesol was investigated. The phenolic profile of PomeGr was assessed by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) analysis before and after exposure to C. albicans. Here, we showed that fungal growth, biofilm formation and AI release were altered by PomeGr treatment. Moreover, the phenolic content of PomeGr was substantially hampered upon exposure to fungal cells; particularly pedunculagin, punicalin, punicalagin, granatin, di-(HHDP-galloyl-hexoside)-pentoside and their isomers as well as ellagic acid-hexoside appeared highly consumed, suggesting their role as bioactive molecules against Candida. Overall, these new insights on the anti-Candida properties of PomeGr and its potential mechanisms of action may represent a relevant step in the design of novel therapeutic approaches against fungal infections.}, } @article {pmid36360105, year = {2022}, author = {Liu, J and Zhu, W and Qin, N and Ren, X and Xia, X}, title = {Propionate and Butyrate Inhibit Biofilm Formation of Salmonella Typhimurium Grown in Laboratory Media and Food Models.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {21}, pages = {}, pmid = {36360105}, issn = {2304-8158}, support = {SQ2022YFD2100005//National Key Research and Development Program of China/ ; J2020044//Science and Technology Research Program of the Liaoning Department of Education/ ; 2022JM-111//Science and Technology Program of Shaanxi Province, China/ ; 31772084//National Natural Science Foundation of China/ ; }, abstract = {Salmonella is among the most frequently isolated foodborne pathogens, and biofilm formed by Salmonella poses a potential threat to food safety. Short-chain fatty acids (SCFAs), especially propionate and butyrate, have been demonstrated to exhibit a beneficial effect on promoting intestinal health and regulating the host immune system, but their anti-biofilm property has not been well studied. This study aims to investigate the effects of propionate or butyrate on the biofilm formation and certain virulence traits of Salmonella. We investigated the effect of propionate or butyrate on the biofilm formation of Salmonella enterica serovar Typhimurium (S. Typhimurium) SL1344 grown in LB broth or food models (milk or chicken juice) by crystal violet staining methods. Biofilm formation was significantly reduced in LB broth and food models and the reduction was visualized using a scanning electron microscope (SEM). Biofilm metabolic activity was attenuated in the presence of propionate or butyrate. Meanwhile, both SCFAs decreased AI-2 quorum sensing based on reporter strain assay. Butyrate, not propionate, could effectively reduce bacterial motility. Bacterial adhesion to and invasion of Caco-2 cells were also significantly inhibited in the presence of both SCFAs. Finally, two SCFAs downregulated virulence genes related to biofilm formation and invasion through real-time polymerase chain reaction (RT-PCR). These findings demonstrate the potential application of SCFAs in the mitigation of Salmonella biofilm in food systems, but future research mimicking food environments encountered during the food chain is necessitated.}, } @article {pmid36360050, year = {2022}, author = {Hou, W and Kang, S and Chang, J and Tian, X and Shi, C}, title = {Correlation Analysis between GlpQ-Regulated Degradation of Wall Teichoic Acid and Biofilm Formation Triggered by Lactobionic Acid in Staphylococcus aureus.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {21}, pages = {}, pmid = {36360050}, issn = {2304-8158}, abstract = {Staphylococcus aureus biofilms are a serious problem in the food industry. Wall teichoic acid (WTA) is crucial in S. aureus biofilm formation. Overexpression of the WTA-hydrolyzing enzyme glycerophosphoryl diester phosphodiesterase (GlpQ), induced by lactobionic acid (LBA), may be related to biofilm formation. We investigated the relationship between the regulation on GlpQ degradation of WTA by LBA and S. aureus biofilm formation. LBA minimum inhibitory concentration for S. aureus was 12.5 mg/mL. Crystal violet staining revealed the LBA-mediated inhibition of S. aureus adhesion and biofilm formation. RT-qPCR revealed the repressed expression of adhesion-related genes by LBA. Scanning electron microscopy revealed the obvious disruption of S. aureus surface structure, confirming the repression of S. aureus adhesion and biofilm formation by LBA. Native-PAGE results suggested that the WTA content of S. aureus was reduced under the inhibition of LBA. Additionally, LBA induced the overexpression of glpQ. Combined with our previous work, these results suggest that glpQ is induced in S. aureus to function in WTA degradation with the addition of LBA, resulting in decreased WTA content and subsequent reduction of adhesion and biofilm formation. The findings provide new insight into the degradation mechanism of S. aureus WTA and indicate the potential of LBA as an anti-biofilm agent.}, } @article {pmid36359854, year = {2022}, author = {Wu, BC and Blimkie, TM and Haney, EF and Falsafi, R and Akhoundsadegh, N and Hancock, REW}, title = {Host Response of Human Epidermis to Methicillin-Resistant Staphylococcus aureus Biofilm Infection and Synthetic Antibiofilm Peptide Treatment.}, journal = {Cells}, volume = {11}, number = {21}, pages = {}, pmid = {36359854}, issn = {2073-4409}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Humans ; *Methicillin-Resistant Staphylococcus aureus/physiology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Epidermis/metabolism ; Peptides/metabolism ; Inflammation/metabolism ; }, abstract = {Bacterial biofilm infections associated with wounded skin are prevalent, recalcitrant, and in urgent need of treatments. Additionally, host responses in the skin to biofilm infections are not well understood. Here we employed a human organoid skin model to explore the transcriptomic changes of thermally-injured epidermis to methicillin-resistant Staphylococcus aureus (MRSA) biofilm colonization. MRSA biofilm impaired skin barrier function, enhanced extracellular matrix remodelling, elicited inflammatory responses including IL-17, IL-12 family and IL-6 family interleukin signalling, and modulated skin metabolism. Synthetic antibiofilm peptide DJK-5 effectively diminished MRSA biofilm and associated skin inflammation in wounded human ex vivo skin. In the epidermis, DJK-5 shifted the overall skin transcriptome towards homeostasis including modulating the biofilm induced inflammatory response, promoting the skin DNA repair function, and downregulating MRSA invasion of thermally damaged skin. These data clarified the underlying immunopathogenesis of biofilm infections and revealed the intrinsic promise of synthetic peptides in reducing inflammation and biofilm infections.}, } @article {pmid36358558, year = {2022}, author = {Butucel, E and Balta, I and McCleery, D and Popescu, CA and Iancu, T and Pet, I and Marcu, A and Horablaga, NM and Stef, L and Corcionivoschi, N}, title = {The Effect Citrox BCL on Legionella pneumophila Mechanisms of Biofilm Formation, Oxidative Stress and Virulence.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358558}, issn = {2076-3921}, support = {49736//Auranta/ ; }, abstract = {Legionella pneumophila is responsible for causing Legionnaires' disease and Pontiac fever, also known as legionellosis. The aim of this study was to investigate the mechanistic effect of a mixture of natural antimicrobials (Citrox BCL) in preventing L. pneumophila biofilm formation and reducing its in vitro virulence. The minimum inhibitory concentrations were detected at 0.06%, and the MBC was established at 0.125%. Based on the growth curve profile, the sub-inhibitory concentration of 0.02% was further used to study the mechanistic implications in the absence of a cytotoxic effect on A549 cells. At 24 h post-infection, Citrox BCL reduced (p = 0.005) the intracellular growth of L. pneumophila when the A549 cells or the bacteria were pre-treated with 0.02% Citrox BCL. This result was replicated when Citrox BCL was added during the 24 h infection assay leading to a reduction in intracellular growth (p = 0.003). Herein we show that at the sub-inhibitory concentration of 0.02%, Citrox CBL lowers the ROS levels in infected A549 cells and causes a 45% reduction in L. pneumophila EPS production, a reduction associated with the decline in biofilm formation. Overall, our results corroborate the low c-di-GMP production with the decrease in biofilm formation and low EPS levels. The low EPS levels seemed to be caused by the downregulation of the tatB and tatC gene expressions. Moreover, inhibition of pvcA and pvcB gene expressions, leading to lower siderophore levels, suggests that Citrox BCL reduces the ability of L. pneumophila to sequester iron and reduce biofilm formation through iron starvation.}, } @article {pmid36358345, year = {2022}, author = {Puvanasundram, P and Chong, CM and Sabri, S and Yusoff, MSM and Lim, KC and Karim, M}, title = {Efficacy of Single and Multi-Strain Probiotics on In Vitro Strain Compatibility, Pathogen Inhibition, Biofilm Formation Capability, and Stress Tolerance.}, journal = {Biology}, volume = {11}, number = {11}, pages = {}, pmid = {36358345}, issn = {2079-7737}, support = {LRGS/1/2019/UPM/01/1/2//Long Research Grant Scheme (LRGS) by Ministry of Education Malaysia/ ; }, abstract = {Compatibility of each strain in a multi-strain probiotic (MSP), along with its properties, becomes a strong base for its formulation. In this study, single-strain probiotics (SSPs) and multi-strain probiotics (MSPs) were evaluated in vitro for strain compatibility, microbial antagonism, biofilm formation capacity, and stress tolerance. Bacillus amyloliquefaciens L11, Enterococcus hirae LAB3, and Lysinibacillus fusiformis SPS11 were chosen as MSP1 candidates because they showed much stronger antagonism to Aeromonas hydrophila and Streptococcus agalactiae than a single probiotic. MSP 2 candidates were Lysinibacillus fusiformis strains SPS11, A1, and Lysinibacillus sphaericus strain NAS32 because the inhibition zone produced by MSP 2 against Vibrio harveyi and Vibrio parahaemolyticus was much higher than that produced by its constituent SSPs. MSP1 in the co-culture assay reduced (p < 0.05) A. hydrophila count from 9.89 ± 0.1 CFU mL−1 to 2.14 ± 0.2 CFU mL−1. The biofilm formation of both MSPs were significantly higher (p < 0.05) than its constituent SSPs and the pathogens. The SSPs in both MSPs generally showed resistance to high temperatures (80, 90, and 100 °C) and a wide range of pH (2 to 9). This in vitro assessment study demonstrates that MSP1 and 2 have the potential to be further explored as multi-strain probiotics on selected aquatic species.}, } @article {pmid36358226, year = {2022}, author = {Scoffone, VC and Irudal, S and AbuAlshaar, A and Piazza, A and Trespidi, G and Barbieri, G and Makarov, V and Migliavacca, R and De Rossi, E and Buroni, S}, title = {Bactericidal and Anti-Biofilm Activity of the FtsZ Inhibitor C109 against Acinetobacter baumannii.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358226}, issn = {2079-6382}, support = {20177J5Y3P//Italian Ministry of University and Research/ ; 20208LLXEJ//Italian Ministry of University and Research/ ; Dipartimenti di Eccellenza, Program 2018-2022//Italian Ministry of University and Research/ ; W000921N//FWO Biofilm Community/ ; }, abstract = {In the last few years, Acinetobacter baumannii has ranked as a number one priority due to its Multi Drug Resistant phenotype. The different metabolic states, such as the one adopted when growing as biofilm, help the bacterium to resist a wide variety of compounds, placing the discovery of new molecules able to counteract this pathogen as a topic of utmost importance. In this context, bacterial cell division machinery and the conserved protein FtsZ are considered very interesting cellular targets. The benzothiadiazole compound C109 is able to inhibit bacterial growth and to block FtsZ GTPase and polymerization activities in Burkholderia cenocepacia, Pseudomonas aeruginosa, and Staphylococcus aureus. In this work, the activity of C109 was tested against a panel of antibiotic sensitive and resistant A. baumannii strains. Its ability to inhibit biofilm formation was explored, together with its activity against the A. baumannii FtsZ purified protein. Our results indicated that C109 has good MIC values against A. baumannii clinical isolates. Moreover, its antibiofilm activity makes it an interesting alternative treatment, effective against diverse metabolic states. Finally, its activity was confirmed against A. baumannii FtsZ.}, } @article {pmid36358217, year = {2022}, author = {Fiallos, NM and Ribeiro Aguiar, AL and da Silva, BN and Pergentino, MLM and Rocha, MFG and Sidrim, JJC and Maia, DCBSC and Cordeiro, RA}, title = {The Potential of Phenothiazines against Endodontic Pathogens: A Focus on Enterococcus-Candida Dual-Species Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358217}, issn = {2079-6382}, support = {http://lattes.cnpq.br/1934399087822977//CNPQ/ ; }, abstract = {Persistent apical periodontitis occurs when the endodontic treatment fails to eradicate the intraradicular infection, and is mainly caused by Gram-positive bacteria and yeasts, such as Enterococcus faecalis and Candida albicans, respectively. Phenothiazines have been described as potential antimicrobials against bacteria and fungi. This study aimed to investigate the antimicrobial potential of promethazine (PMZ) and chlorpromazine (CPZ) against E. faecalis and C. albicans dual-species biofilms. The susceptibility of planktonic cells to phenothiazines, chlorhexidine (CHX) and sodium hypochlorite (NaOCl) was initially analyzed by broth microdilution. Interaction between phenothiazines and CHX was examined by chequerboard assay. The effect of NaOCl, PMZ, CPZ, CHX, PMZ + CHX, and CPZ + CHX on biofilms was investigated by susceptibility assays, biochemical and morphological analyses. Results were evaluated through one-way ANOVA and Tukey's multiple comparison post-test. PMZ, alone or in combination with irrigants, was the most efficient phenothiazine, capable of reducing cell counts, biomass, biovolume, carbohydrate and protein contents of dual-species biofilms. Neither PMZ nor CPZ increased the antimicrobial activity of CHX. Further investigations of the properties of phenothiazines should be performed to encourage their use in endodontic clinical practice.}, } @article {pmid36358189, year = {2022}, author = {Meza-Villezcas, A and Carballo-Castañeda, RA and Moreno-Ulloa, A and Huerta-Saquero, A}, title = {Metabolomic Profiling of the Responses of Planktonic and Biofilm Vibrio cholerae to Silver Nanoparticles.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358189}, issn = {2079-6382}, support = {284385//Consejo Nacional de Ciencia y Tecnología/ ; 300437//Consejo Nacional de Ciencia y Tecnología/ ; }, abstract = {Vibrio cholerae causes cholera and can switch between planktonic and biofilm lifeforms, where biofilm formation enhances transmission, virulence, and antibiotic resistance. Due to antibiotic microbial resistance, new antimicrobials including silver nanoparticles (AgNPs) are being studied. Nevertheless, little is known about the metabolic changes exerted by AgNPs on both microbial lifeforms. Our objective was to evaluate the changes in the metabolomic profile of V. cholerae planktonic and biofilm cells in response to sublethal concentrations of AgNPs using MS2 untargeted metabolomics and chemoinformatics. A total of 690 metabolites were quantified among all groups. More metabolites were significantly modulated in planktonic cells (n = 71) compared to biofilm (n = 37) by the treatment. The chemical class profiles were distinct for both planktonic and biofilm, suggesting a phenotype-dependent metabolic response to the nanoparticles. Chemical enrichment analysis showed altered abundances of oxidized fatty acids (FA), saturated FA, phosphatidic acids, and saturated stearic acid in planktonic cells treated with AgNPs, which hints at a turnover of the membrane. In contrast, no chemical classes were enriched in the biofilm. In conclusion, this study suggests that the response of V. cholerae to silver nanoparticles is phenotype-dependent and that planktonic cells experience a lipid remodeling process, possibly related to an adaptive mechanism involving the cell membrane.}, } @article {pmid36358169, year = {2022}, author = {Navarro, S and Sherman, E and Colmer-Hamood, JA and Nelius, T and Myntti, M and Hamood, AN}, title = {Urinary Catheters Coated with a Novel Biofilm Preventative Agent Inhibit Biofilm Development by Diverse Bacterial Uropathogens.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358169}, issn = {2079-6382}, support = {none//Next Science LLC, Jacksonville, FL, Unites Stataes/ ; }, abstract = {Despite the implementation of stringent guidelines for the prevention of catheter-associated (CA) urinary tract infection (UTI), CAUTI remains one of the most common health care-related infections. We previously showed that an antimicrobial/antibiofilm agent inhibited biofilm development by Gram-positive and Gram-negative bacterial pathogens isolated from human infections. In this study, we examined the ability of a novel biofilm preventative agent (BPA) coating on silicone urinary catheters to inhibit biofilm formation on the catheters by six different bacterial pathogens isolated from UTIs: three Escherichia coli strains, representative of the most common bacterium isolated from UTI; one Enterobacter cloacae, a multidrug-resistant isolate; one Pseudomonas aeruginosa, common among patients with long-term catheterization; and one isolate of methicillin-resistant Staphylococcus aureus, as both a Gram-positive and a resistant organism. First, we tested the ability of these strains to form biofilms on urinary catheters made of red rubber, polyvinyl chloride (PVC), and silicone using the microtiter plate biofilm assay. When grown in artificial urine medium, which closely mimics human urine, all tested isolates formed considerable biofilms on all three catheter materials. As the biofilm biomass formed on silicone catheters was 0.5 to 1.6 logs less than that formed on rubber or PVC, respectively, we then coated the silicone catheters with BPA (benzalkonium chloride, polyacrylic acid, and glutaraldehyde), and tested the ability of the coated catheters to further inhibit biofilm development by these uropathogens. Compared with the uncoated silicone catheters, BPA-coated catheters completely prevented biofilm development by all the uropathogens, except P. aeruginosa, which showed no reduction in biofilm biomass. To explore the reason for P. aeruginosa resistance to the BPA coating, we utilized two specific lipopolysaccharide (LPS) mutants. In contrast to their parent strain, the two mutants failed to form biofilms on the BPA-coated catheters, which suggests that the composition of P. aeruginosa LPS plays a role in the resistance of wild-type P. aeruginosa to the BPA coating. Together, our results suggest that, except for P. aeruginosa, BPA-coated silicone catheters may prevent biofilm formation by both Gram-negative and Gram-positive uropathogens.}, } @article {pmid36358132, year = {2022}, author = {Fernandes, GL and Vieira, APM and Danelon, M and Emerenciano, NG and Berretta, AA and Buszinski, AFM and Hori, JI and Lima, MHF and Reis, TFD and Lima, JA and Delbem, ACB and Silva, SCMD and Barbosa, DB}, title = {Pomegranate Extract Potentiates the Anti-Demineralizing, Anti-Biofilm, and Anti-Inflammatory Actions of Non-Alcoholic Mouthwash When Associated with Sodium-Fluoride Trimetaphosphate.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358132}, issn = {2079-6382}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 2018/06582-5//São Paulo Research Foundation/ ; }, abstract = {This study investigated the anti-caries and anti-inflammatory effects of mouthwash formulations containing Punica granatum (pomegranate) peel extract (PPE), sodium-trimetaphosphate, and low concentrations of fluoride. PPE was characterized using high-performance liquid chromatography (ellagic acid and punicalagin). Total phenolics were quantified among formulations, and their stability was analyzed for 28 days. The formulation effects were evaluated as follows: (1) inorganic component concentration and reduced demineralization on bovine enamel blocks subjected to pH cycling; (2) anti-biofilm effect on dual-biofilms of Streptococcus mutans ATCC 25175 and Candida albicans ATCC 10231 treated for 1 and 10 min, respectively; and (3) cytotoxicity and production of inflammatory mediators (interleukin-6 and tumor necrosis factor-alpha). The formulation containing 3% PPE, 0.3% sodium-trimetaphosphate, and 225 ppm of fluoride resulted in a 34.5% surface hardness loss; a 13% (treated for 1 min) and 36% (treated for 10 min) biofilm reduction in S. mutans; a 26% (1 min) and 36% (10 min) biofilm reduction in C. albicans; absence of cytotoxicity; and anti-inflammatory activity confirmed by decreased interleukin-6 production in mouse macrophages. Thus, our results provide a promising prospect for the development of an alcohol-free commercial dental product with the health benefits of P. granatum that have been recognized for a millennium.}, } @article {pmid36358129, year = {2022}, author = {Sun, C and Zhao, X and Jiao, Z and Peng, J and Zhou, L and Yang, L and Huang, M and Tian, C and Guo, G}, title = {The Antimicrobial Peptide AMP-17 Derived from Musca domestica Inhibits Biofilm Formation and Eradicates Mature Biofilm in Candida albicans.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {36358129}, issn = {2079-6382}, support = {82060381//National Natural Science Foundation of China/ ; 82002180//National Natural Science Foundation of China/ ; ZK[2022] general project 345//Science and Technology Planning Project of Guizhou Province/ ; (ZK[2022] Key Program 039)//Guizhou Provincial Natural Science Foundation/ ; }, abstract = {The biofilm formation of C. albicans represents a major virulence factor during candidiasis. Biofilm-mediated drug resistance has necessitated the search for a new antifungal treatment strategy. In our previous study, a novel antimicrobial peptide named AMP-17 derived from Musca domestica was confirmed to have significant antifungal activity and suppress hyphal growth greatly in C. albicans. In the current work, we aimed to investigate the antibiofilm property of AMP-17 in C. albicans and explore the underlying mechanism. An antifungal susceptibility assay showed that AMP-17 exerted a strong inhibitory efficacy on both biofilm formation and preformed biofilms in C. albicans. Furthermore, AMP-17 was found to block the yeast-to-hypha transition and inhibit the adhesion of biofilm cells with a reduction in cellular surface hydrophobicity. A morphological analysis revealed that AMP-17 indeed suppressed typical biofilm formation and damaged the structures of the preformed biofilm. The RNA-seq showed that the MAPK pathway, biosynthesis of antibiotics, and essential components of the cell were mainly enriched in the biofilm-forming stage, while the citrate cycle (TCA cycle), phenylamine metabolism, and propanoate metabolism were enriched after the biofilm matured. Moreover, the co-expressed DEGs in the two pairwise comparisons highlighted the terms of transmembrane transporter activity, regulation of filamentation, and biofilm formation as important roles in the antibiofilm effect of AMP-17. Additionally, qRT-PCR confirmed that the level of the genes involved in cell adhesion, filamentous growth, MAPK, biofilm matrix, and cell dispersal was correspondingly altered after AMP-17 treatment. Overall, our findings reveal the underlying antibiofilm mechanisms of AMPs in C. albicans, providing an interesting perspective for the development of effective antifungal agents with antibiofilm efficacy in Candida spp.}, } @article {pmid36358052, year = {2022}, author = {Tong, J and Cui, L and Wang, D and Wang, X and Liu, Z}, title = {Simultaneous high p-nitrophenol concentration and nitrogen removal by two-stage membrane biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {5}, pages = {1153-1167}, doi = {10.2166/wst.2022.246}, pmid = {36358052}, issn = {0273-1223}, mesh = {Humans ; *Nitrogen/metabolism ; *Wastewater ; Bioreactors ; Denitrification ; Nitrophenols ; Biofilms ; Waste Disposal, Fluid ; }, abstract = {P-nitrophenol (PNP) is highly toxic and difficult to degrade, causing great harm to the ecological environment and human health. A two-stage bench-scale membrane biofilm reactor (MBfR) was constructed to treat wastewater containing high concentration of PNP and the generated nitrogen without external organic carbon sources. The two reactors were supplied with oxygen and methane, respectively. O2-MBfR was used for the degradation of PNP and the improvement of wastewater biodegradability. CH4-MBfR was used for the total nitrogen (TN) removal treatment from O2-MBfR effluent. In this experiment, the performance of the two-stage MBfR process was evaluated and optimized by adjusting operational parameters (aeration pressure, HRT, and pH). Under the optimal operation parameters, the removal efficiencies of PNP (100 mg/L) and TN attained 89.70% and 69.24%, respectively, and the removal loads were 0.930 g·m[-2]·d[-1] and 241.42 mg·m[-2]·d[-1], respectively. The reactor was able to accommodate the concentrations of PNP up to 200-400 mg/L, and the reactor reached maximum efficiency throughout the process when the concentration of PNP in the wastewater was 250 mg/L. The removal rates of PNP and TN reached 95.0% and 69.48%, respectively, and the removal loads were 2.37 g·m[-2]·d[-1] and 96.22 mg·m[-2]·d[-1], respectively. This research provides a better solution for multi-MBfR to treat toxic industrial wastewater containing phenol, nitrophenol, and further TN removal, which would not release any air pollutants into the atmosphere.}, } @article {pmid36354904, year = {2022}, author = {Štefánek, M and Černáková, L and Dekkerová, J and Bujdáková, H}, title = {Photodynamic Inactivation Effectively Eradicates Candida auris Biofilm despite Its Interference with the Upregulation of CDR1 and MDR1 Efflux Genes.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {11}, pages = {}, pmid = {36354904}, issn = {2309-608X}, support = {APVV-18-0075//Slovak Research and Development Agency/ ; APVV-21-0302//Slovak Research and Development Agency/ ; VEGA 1/0537/19//Ministry of Education, Science, Research and Sport of the Slovak Republic/ ; }, abstract = {Candida auris, in recent years, has emerged as a dangerous nosocomial pathogen. It represents a challenge for effective treatment because of its multiresistance. Photodynamic inactivation (PDI) is a promising way to solve problems with a wide range of resistant microorganisms. This study aimed to use PDI for the eradication of C. auris biofilms. Moreover, the regulation of the CDR1, CDR2, and MDR1 resistance genes was studied. Experiments were performed on 24 h biofilms formed by three clinical isolates of C. auris in vitro. PDI was performed in the presence of the photosensitizer methylene blue (0.25 mM) and samples were irradiated with a red laser (λ = 660 nm, 190 mW/cm[2]) for 79, 120, and 300 s. To confirm the PDI effect, confocal laser scanning microscopy was performed after treatment. Effective PDI was achieved in all strains. The highest inhibition was observed after 300 s irradiation, with over 90% inhibition compared with the non-irradiated control sample. PDI was observed to upregulate the expression of the CDR1 gene, but mainly the MDR1 gene. Despite this observation, PDI significantly decreased the survival of C. auris biofilm cells and proved to have great potential for the eradication of problematic resistant yeasts.}, } @article {pmid36354337, year = {2022}, author = {Lichtenberg, M and Kvich, L and Larsen, SLB and Jakobsen, TH and Bjarnsholt, T}, title = {Inoculum Concentration Influences Pseudomonas aeruginosa Phenotype and Biofilm Architecture.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0313122}, pmid = {36354337}, issn = {2165-0497}, mesh = {Humans ; *Pseudomonas aeruginosa/genetics ; Anti-Bacterial Agents/pharmacology/metabolism ; Biofilms ; Phenotype ; Alginates/metabolism ; *Pseudomonas Infections/microbiology ; }, abstract = {In infections, bacterial cells are often found as relatively small multicellular aggregates characterized by a heterogeneous distribution of phenotype, genotype, and growth rates depending on their surrounding microenvironment. Many laboratory models fail to mimic these characteristics, and experiments are often initiated from planktonic bacteria given optimal conditions for rapid growth without concerns about the microenvironmental characteristics during biofilm maturation. Therefore, we investigated how the initial bacterial concentration (henceforth termed the inoculum) influences the microenvironment during initial growth and how this affects the sizes and distribution of developed aggregates in an embedded biofilm model-the alginate bead biofilm model. Following 24 h of incubation, the viable biomass was independent of starting inoculum but with a radically different microenvironment which led to differences in metabolic activity depending on the inoculum. The inoculum also affected the number of cells surviving treatment with the antibiotic tobramycin, where the highest inoculum showed higher survival rates than the lowest inoculum. The change in antibiotic tolerance was correlated with cell-specific RNA content and O2 consumption rates, suggesting a direct role of metabolic activity. Thus, the starting number of bacteria results in different phenotypic trajectories governed by different microenvironmental characteristics, and we demonstrate some of the possible implications of such physiological gradients on the outcome of in vitro experiments. IMPORTANCE Biofilm aggregates grown in the alginate bead biofilm model bear resemblance to features of in vivo biofilms. Here, we show that changing the initial concentration of bacteria in the biofilm model leads to widely different behavior of the bacteria following an incubation period. This difference is influenced by the local conditions experienced by the bacteria during growth, which impact their response to antibiotic treatment. Our study provides a framework for manipulating aggregate sizes in in vitro biofilm models. It underlines the importance of how experiments are initiated, which can profoundly impact the outcomes and interpretation of microbiological experiments.}, } @article {pmid36354319, year = {2022}, author = {He, X and Zhang, W and Cao, Q and Li, Y and Bao, G and Lin, T and Bao, J and Chang, C and Yang, C and Yin, Y and Xu, J and Ren, Z and Jin, Y and Lu, F}, title = {Global Downregulation of Penicillin Resistance and Biofilm Formation by MRSA Is Associated with the Interaction between Kaempferol Rhamnosides and Quercetin.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0278222}, pmid = {36354319}, issn = {2165-0497}, mesh = {*Methicillin-Resistant Staphylococcus aureus ; Quercetin/pharmacology ; Kaempferols/pharmacology ; Down-Regulation ; Anti-Bacterial Agents/pharmacology ; Flavonoids/pharmacology ; Biofilms ; Penicillin Resistance ; Microbial Sensitivity Tests ; }, abstract = {The rapid development of methicillin-resistant Staphylococcus aureus (MRSA) drug resistance and the formation of biofilms seriously challenge the clinical application of classic antibiotics. Extracts of the traditional herb Chenopodium ambrosioides L. were found to have strong antibiofilm activity against MRSA, but their mechanism of action remains poorly understood. This study was designed to investigate the antibacterial and antibiofilm activities against MRSA of flavonoids identified from C. ambrosioides L. in combination with classic antibiotics, including ceftazidime, erythromycin, levofloxacin, penicillin G, and vancomycin. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the nonvolatile chemical compositions. Reverse transcription (RT)-PCR was used to investigate potential multitargets of flavonoids based on global transcriptional responses of virulence and antibiotic resistance. A synergistic antibacterial and biofilm-inhibiting activity of the alcoholic extract of the ear of C. ambrosioides L. in combination with penicillin G was observed against MRSA, which proved to be closely related to the interaction of the main components of kaempferol rhamnosides with quercetin. In regard to the mechanism, the increased sensitivity of MRSA to penicillin G was shown to be related to the downregulation of penicillinase with SarA as a potential drug target, while the antibiofilm activity was mainly related to downregulation of various virulence factors involved in the initial and mature stages of biofilm development, with SarA and/or σB as drug targets. This study provides a theoretical basis for further exploration of the medicinal activity of kaempferol rhamnosides and quercetin and their application in combination with penicillin G against MRSA biofilm infection. IMPORTANCE In this study, the synergistic antibacterial and antibiofilm effects of the traditional herb C. ambrosioides L. and the classic antibiotic penicillin G on MRSA provide a potential strategy to deal with the rapid development of MRSA antibiotic resistance. This study also provides a theoretical basis for further optimizing the combined effect of kaempferol rhamnosides, quercetin, and penicillin G and exploring anti-MRSA biofilm infection research with SarA and σB as drug targets.}, } @article {pmid36354060, year = {2022}, author = {Banerjee, A and Chowdhury, P and Bauri, K and Saha, B and De, P}, title = {Inhibition and eradication of bacterial biofilm using polymeric materials.}, journal = {Biomaterials science}, volume = {11}, number = {1}, pages = {11-36}, doi = {10.1039/d2bm01276f}, pmid = {36354060}, issn = {2047-4849}, mesh = {*Biofilms ; *Bacteria ; Anti-Bacterial Agents/pharmacology ; Polymers/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Biofilms, ubiquitous in nature, are three-dimensional complex microbial communities sheathed in a self-secreted extracellular polymeric matrix. Infections caused by these communities have sprouted as serious threats to global healthcare systems due to their intrinsic tolerance toward conventional antibiotics. There is a huge demand for alternative "cutting-edge" materials featuring strong antibiofilm abilities to mitigate and/or exterminate pre-matured biofilms. Natural or synthetic macromolecule-based compounds have evolved as one of the most sought-after materials because of their unique stimulus-directed selective targeting efficiency to the bacterial cell, antibiotic-encapsulation ability endowing them with a synergistic effect, and highly dense embedded cationic functionalities that promote accumulation within the biofilm. In this comprehensive review, we aim to highlight the progress made in inhibiting or eradicating bacterial biofilms using various forms of polymeric material including cationic and charge-switchable macromolecules, conjugated polymers, polymeric metal nanocomposites, hydrogels, and supramolecular polymers. We particularly emphasize understanding the underlying antibiofilm mechanisms of each presented example ushered in by state-of-the-art synthetic strategies. Lastly, focusing on bench-to-bedside, the review is concluded by providing some forthcoming aspects and possible future development directions to expand polymer-based antibiofilm research, keeping their clinical translations in mind.}, } @article {pmid36354005, year = {2022}, author = {Raad, N and Tandon, D and Hapfelmeier, S and Polacek, N}, title = {The stationary phase-specific sRNA FimR2 is a multifunctional regulator of bacterial motility, biofilm formation and virulence.}, journal = {Nucleic acids research}, volume = {50}, number = {20}, pages = {11858-11875}, pmid = {36354005}, issn = {1362-4962}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Escherichia coli/genetics/metabolism/pathogenicity ; *Escherichia coli Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; *RNA, Bacterial/genetics/metabolism ; RNA, Small Untranslated/genetics/metabolism ; RNA-Binding Proteins/genetics/metabolism ; Virulence ; Virulence Factors/genetics/metabolism ; }, abstract = {Bacterial pathogens employ a plethora of virulence factors for host invasion, and their use is tightly regulated to maximize infection efficiency and manage resources in a nutrient-limited environment. Here we show that during Escherichia coli stationary phase the 3' UTR-derived small non-coding RNA FimR2 regulates fimbrial and flagellar biosynthesis at the post-transcriptional level, leading to biofilm formation as the dominant mode of survival under conditions of nutrient depletion. FimR2 interacts with the translational regulator CsrA, antagonizing its functions and firmly tightening control over motility and biofilm formation. Generated through RNase E cleavage, FimR2 regulates stationary phase biology by fine-tuning target mRNA levels independently of the chaperones Hfq and ProQ. The Salmonella enterica orthologue of FimR2 induces effector protein secretion by the type III secretion system and stimulates infection, thus linking the sRNA to virulence. This work reveals the importance of bacterial sRNAs in modulating various aspects of bacterial physiology including stationary phase and virulence.}, } @article {pmid36351347, year = {2023}, author = {Martínez-Campos, S and González-Pleiter, M and Rico, A and Schell, T and Vighi, M and Fernández-Piñas, F and Rosal, R and Leganés, F}, title = {Time-course biofilm formation and presence of antibiotic resistance genes on everyday plastic items deployed in river waters.}, journal = {Journal of hazardous materials}, volume = {443}, number = {Pt B}, pages = {130271}, doi = {10.1016/j.jhazmat.2022.130271}, pmid = {36351347}, issn = {1873-3336}, mesh = {*Plastics/analysis ; Anti-Bacterial Agents/pharmacology ; Rivers ; Drug Resistance, Microbial/genetics ; *Microbiota/genetics ; Biofilms ; Genes, Bacterial ; }, abstract = {The plastisphere has been widely studied in the oceans; however, there is little information on how living organisms interact with the plastisphere in freshwater ecosystems, and particularly on how this interaction changes over time. We have characterized, over one year, the evolution of the eukaryotic and bacterial communities colonizing four everyday plastic items deployed in two sites of the same river with different anthropogenic impact. α-diversity analyses showed that site had a significant role in bacterial and eukaryotic diversity, with the most impacted site having higher values of the Shannon diversity index. β-diversity analyses showed that site explained most of the sample variation followed by substrate type (i.e., plastic item) and time since first colonization. In this regard, core microbiomes/biomes in each plastic at 1, 3, 6 and 12 months could be identified at genus level, giving a global overview of the evolution of the plastisphere over time. The measured concentration of antibiotics in the river water positively correlated with the abundance of antibiotic resistance genes (ARGs) on the plastics. These results provide relevant information on the temporal dynamics of the plastisphere in freshwater ecosystems and emphasize the potential contribution of plastic items to the global spread of antibiotic resistance.}, } @article {pmid36350889, year = {2022}, author = {Alba, MLS and Durán-Rodriguez, AT and Pulido, LMS and Escobar-Pérez, J and Gutiérrez, SA and Ospina, JN and Bermúdez, GP and Molina, LCM}, title = {Peptides DLL37-1 and LL37-1, an alternative to inhibit biofilm formation in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {94}, number = {3}, pages = {e20210848}, doi = {10.1590/0001-3765202220210848}, pmid = {36350889}, issn = {1678-2690}, mesh = {Humans ; *Staphylococcus aureus ; Staphylococcus epidermidis ; Adhesins, Bacterial ; *Staphylococcal Infections ; Biofilms ; Peptides ; }, abstract = {Staphylococcus aureus and Staphylococcus epidermidis have microbial surface components recognizing adhesive matrix molecules (MSCRAMM) adhesion proteins that enhance their biofilm formation ability, as well as virulence factors that influence morbidity and mortality in hospital settings. In this work, four peptides analogous of the peptide LL-37 that were evaluated to inhibit biofilm formation and its action potential on the expression of MSCRAMM proteins in clinical isolates through different tests, such as crystal violet, PCR and qPCR. In total, 96.8% of S. aureus were strong in biofilm formation in contrast to 48.4% of S. epidermidis. sdrG and sdrF genes were present in 100% of S. epidermidis strains and in all isolates. In S. aureus, specific genes that code for MSCRAMM proteins were detected: clfA (89%), clFB, sdrC and fnBA (94%). The peptides did not show hemolytic or cytotoxic activity. In this study, it was evidenced that of the peptides DLL37-1 at a 5 µM concentration was an efficacious antimicrobial agent and depicted greater biofilm inhibition in both bacterial species. Exhibiting a significant inhibition rate in S. aureus, this peptide caused a negative regulation in the expression of the genes clfA and sdrC, showed greater biological activity.}, } @article {pmid36350834, year = {2022}, author = {Mirzaei, R and Yousefimashouf, R and Arabestani, MR and Sedighi, I and Alikhani, MY}, title = {The issue beyond resistance: Methicillin-resistant Staphylococcus epidermidis biofilm formation is induced by subinhibitory concentrations of cloxacillin, cefazolin, and clindamycin.}, journal = {PloS one}, volume = {17}, number = {11}, pages = {e0277287}, pmid = {36350834}, issn = {1932-6203}, mesh = {Humans ; Staphylococcus epidermidis ; Cefazolin/pharmacology ; Clindamycin/pharmacology ; Vancomycin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Methicillin Resistance ; Cloxacillin ; *Staphylococcal Infections/microbiology ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; }, abstract = {Staphylococcus epidermis is one of the most frequent causes of device-associated infections due to biofilm formation. Current reports noted that subinhibitory concentrations of antibiotics induce biofilm production in some bacteria. Accordingly, we evaluated the effect of exposure of different subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin on the biofilm formation of methicillin-resistant S. epidermidis (MRSE). Antimicrobial susceptibility testing and minimum inhibitory/bactericidal concentration of antimicrobial agents were determined. MRSE isolates were selected, and their biofilm formation ability was evaluated. The effect of subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin, antibiotics selected among common choices in the clinic, on MRSE biofilm formation was determined by the microtitre method. Besides, the effect of subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin on the expression of the biofilm-associated genes icaA and atlE was evaluated by Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR). Antimicrobial susceptibility patterns of MRSE strains showed a high level of resistance as follows: 80%, 53.3%, 33.3%, 33.3%, and 26.6%, for erythromycin, trimethoprim-sulfamethoxazole, tetracycline, clindamycin, and gentamicin, respectively. Besides, 73.3% of S. epidermidis strains were Multidrug-resistant (MDR). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were in the range of 0.5 to512 μg/mL and 1 to1024 μg/mL for cloxacillin, 0.125 to256 μg/mL and 1 to512 μg/mL for cefazolin, 0.125 to64 μg/mL and 4 to>1024 μg/mL for clindamycin, and 2 to32 μg/mL and 4 to32 μg/mL for vancomycin, respectively. The findings showed that subinhibitory concentrations of cloxacillin, cefazolin, and clindamycin induce biofilm production in MRSE strains. In particular, the OD values of strains were in the range of 0.09-0.95, 0.05-0.86, and 0.06-1 toward cloxacillin, cefazolin, and clindamycin, respectively. On the other hand, exposure to subinhibitory vancomycin concentrations did not increase the biofilm formation in MRSE strains. The findings also demonstrated that sub-MIC of antibiotics up-regulated biofilm-associated genes. In particular, atlE and icaA were up-regulated 0.062 to 1.16 and 0.078 to 1.48 folds, respectively, for cloxacillin, 0.11 to 0.8, and 0.1 to 1.3 folds for cefazolin, 0.18 to 0.98, and 0.19 to 1.4 folds, respectively, for clindamycin. In contrast, the results showed that sub-MIC of vancomycin did not increase the biofilm-associated genes. These findings overall show that exposure to sub-MIC of traditional antibiotics can cause biofilm induction in MRSE, thereby increasing the survival and persistence on various surfaces that worsen the condition of comorbid infections.}, } @article {pmid36350792, year = {2022}, author = {Li, M and Mai, B and Wang, A and Gao, Y and Wang, X and Liu, X and Song, S and Liu, Q and Wei, S and Wang, P}, title = {Correction: Photodynamic antimicrobial chemotherapy with cationic phthalocyanines against Escherichia coli planktonic and biofilm cultures.}, journal = {RSC advances}, volume = {12}, number = {48}, pages = {31091-31092}, doi = {10.1039/d2ra90106d}, pmid = {36350792}, issn = {2046-2069}, abstract = {[This corrects the article DOI: 10.1039/C7RA06073D.].}, } @article {pmid36349578, year = {2023}, author = {Zhou, G and Wang, YS and Peng, H and Li, SJ and Sun, TL and Li, CL and Shi, QS and Xie, XB}, title = {ompX contribute to biofilm formation, osmotic response and swimming motility in Citrobacter werkmanii.}, journal = {Gene}, volume = {851}, number = {}, pages = {147019}, doi = {10.1016/j.gene.2022.147019}, pmid = {36349578}, issn = {1879-0038}, mesh = {Humans ; *Swimming ; *Citrobacter/genetics ; Biofilms ; }, abstract = {Citrobacter werkmanii, an aerobe and mesophilic Proteobacterium, is universal in industrial putrefaction, coastal water, and human blood. Our previous studies have discovered that outer membrane protein X (OmpX) of C. werkmanii is involved in calcium response, but the underlying mechanisms and its molecular characteristics remain elusive. To that end, the ompX gene was deleted from the genome of C. werkmanii and its phenotypic variations were thoroughly investigated in conjunction with the wild type (WT) and complementary strains using biochemical and molecular techniques such as RNA-Seq, respectively. The results demonstrated that deleting ompX reduces biofilm formation on polystyrene and glass surfaces. Meanwhile, ΔompX's swimming ability but not for its twitching or swarming abilities, was also reduced on semi-solid plates compared with WT, which was caused by inhibition of flagellar assembly genes, such as flgC, flhB, and fliE, etc. Furthermore, ompX inactivation altered susceptibility to various bactericide classes, as well as responses to Ca[2+] and Mg[2+] stress. In addition, when compared to WT, ΔompX captures a total of 1,357 deferentially expressed genes (DEGs), of which 465 were up-regulated and 892 were down-regulated, which can be enriched into various GO ontology and KEGG pathway terms. Furthermore, ompX, as well as ompD and ompW, can be modulated at the transcriptional levels by rbsR and tdcA. Overall, the ompX gene contributed to a variety of biological functions in C. werkmanii and could be served as a targeted site for controlling biofilm formation and developing new bactericides.}, } @article {pmid36346844, year = {2022}, author = {Buzzá, HH and Alves, F and Tomé, AJB and Chen, J and Kassab, G and Bu, J and Bagnato, VS and Zheng, G and Kurachi, C}, title = {Porphyrin nanoemulsion for antimicrobial photodynamic therapy: effective delivery to inactivate biofilm-related infections.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {46}, pages = {e2216239119}, pmid = {36346844}, issn = {1091-6490}, support = {FDN154326//Canadian Institute of Health Research/ ; }, mesh = {Mice ; Animals ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; *Porphyrins/pharmacology ; Staphylococcus aureus ; Biofilms ; *Anti-Infective Agents/pharmacology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The management of biofilm-related infections is a challenge in healthcare, and antimicrobial photodynamic therapy (aPDT) is a powerful tool that has demonstrated a broad-spectrum activity. Nanotechnology has been used to increase the aPDT effectiveness by improving the photosensitizer's delivery properties. NewPS is a simple, versatile, and safe surfactant-free nanoemulsion with a porphyrin salt shell encapsulating a food-grade oil core with promising photodynamic action. This study evaluated the use of NewPS for aPDT against microorganisms in planktonic, biofilm, and in vivo models of infected wounds. First, the potential of NewPS-mediated aPDT to inactivate Streptococcus pneumoniae and Staphylococcus aureus suspensions was evaluated. Then, a series of protocols were assessed against S. aureus biofilms by means of cell viability and confocal microscopy. Finally, the best biofilm protocol was used for the treatment of S. aureus in a murine-infected wound model. A high NewPS-bacteria cell interaction was achieved since 0.5 nM and 30 J/cm[2] was able to kill S. pneumoniae suspension. In the S. aureus biofilm, enhanced efficacy of NewPS-aPDT was achieved when 100 µM of NewPS was applied with longer periods of incubation at the light dose of 60 J/cm[2]. The best single and double-session protocol reduced 5.56 logs and 6.03 logs, respectively, homogeneous NewPS distribution, resulting in a high number of dead cells after aPDT. The in vivo model showed that one aPDT session enabled a reduction of 6 logs and faster tissue healing than the other groups. In conclusion, NewPS-aPDT may be considered a safe and effective anti-biofilm antimicrobial photosensitizer.}, } @article {pmid36345065, year = {2023}, author = {Wang, Y and Xu, H and Yao, H and Liu, B and Ding, M and Lin, T and Mo, T and Gao, L and Zhang, L}, title = {Insights into the role of prechlorination in algae-laden raw water distribution process: Algal organic matter and microcystin-LR release, extracellular polymeric substances (EPS) aggregation, and pipeline biofilm communities.}, journal = {Journal of hazardous materials}, volume = {443}, number = {Pt B}, pages = {130306}, doi = {10.1016/j.jhazmat.2022.130306}, pmid = {36345065}, issn = {1873-3336}, mesh = {*Extracellular Polymeric Substance Matrix ; *Chlorine ; Microcystins ; Biofilms ; }, abstract = {Prechlorination routinely applied for the treatment of algae-laden raw water has received extensive attention due to its influence on water quality and aquatic microbes. In this study, prechlorination experiments with different doses were conducted in sets of model raw water distribution systems. With the elevated dose of chlorine and prolonged hydraulic retention time (HRT), the ratio of intact algal cells decreased, and the stability of water enhanced. Dissolved organic carbon (DOC) and nitrogen (DON) increased when chlorine dose elevated from 0 to 0.5 mg/L but decreased with elevations from 0.5 to 2.0 mg/L, while UV254 showed a monotonically increasing tendency. DOC, DON and extracellular microcystin-LR increase initially and decrease thereafter with the prolonged HRT. Notably, the effects of prechlorination on extracellular polymeric substances aggregation behavior on pipe walls and microbial community composition was revealed, providing more profound understanding of the community dynamics in this engineered system. This study helped optimize strategies to improve the stability and efficiency of pretreatment of algae-laden water.}, } @article {pmid36344808, year = {2022}, author = {Rathi, B and Gupta, S and Kumar, P and Kesarwani, V and Dhanda, RS and Kushwaha, SK and Yadav, M}, title = {Anti-biofilm activity of caffeine against uropathogenic E. coli is mediated by curli biogenesis.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {18903}, pmid = {36344808}, issn = {2045-2322}, mesh = {*Biofilms/drug effects ; *Caffeine/pharmacology ; Fimbriae, Bacterial/metabolism ; Molecular Docking Simulation ; *Uropathogenic Escherichia coli/drug effects ; }, abstract = {Biofilms are assemblages of sessile microorganisms that form an extracellular matrix around themselves and mediate attachment to surfaces. The major component of the extracellular matrix of Uropathogenic E. coli and other Enterobacteriaceae are curli fibers, making biofilms robust and resistant to antimicrobials. It is therefore imperative to screen antibiofilm compounds that can impair biofilm formation. In the present study, we investigated the curli-dependent antibiofilm activity of caffeine against UPEC strain CFT073 and commensal strain E. coli K-12MG1655.Caffeine significantly reduced the biofilm formation of both UPEC and E. coli K-12 by 86.58% and 91.80% respectively at 48 mM caffeine as determined by Crystal Violet assay. These results were further confirmed by fluorescence microscopy and Scanning Electron Microscope (SEM). Caffeine significantly reduced the cytotoxicity and survivability of UPEC. Molecular docking analysis revealed a strong interaction between caffeine and curli regulator protein (Csg D) of E. coli. The qRT-PCR data also showed significant downregulation in the expression of CsgBA and the CsgDEFG operon at both 24 mM and 48 mM caffeine. The findings revealed that caffeine could inhibit E. coli biofilm formation by regulating curli assembly and thus may be used as an alternative therapeutic strategy for the treatment of chronic E. coli biofilm-related infections.}, } @article {pmid36343771, year = {2022}, author = {Oda, S and Tanikawa, A}, title = {A new plate-hanging method for biofilm quantification and its application to evaluate the role of surface hydrophobicity.}, journal = {Journal of microbiological methods}, volume = {203}, number = {}, pages = {106608}, doi = {10.1016/j.mimet.2022.106608}, pmid = {36343771}, issn = {1872-8359}, mesh = {*Bacterial Adhesion ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Yeasts ; Bacteria ; Surface Properties ; }, abstract = {A novel procedure for the quantitative analysis of biofilm formation by bacteria and yeasts, the Plate-hanging method, was developed. In this system, various polymer disks were hung from the lid of a 6-well plate, immersed in a cell suspension, and moderately shaken (70 rpm). In order to verify the validity of the procedure, the effects of the solid surface hydrophobicity of the test disks and the cell surface hydrophobicities of microorganisms on biofilm formation were investigated. Biofilm formation of bacteria and yeasts on the solid surface strongly depended on hydrophobic interactions between the solid surface and the cell surface. A positive correlation between the hydrophobic properties of substratum and cell surfaces was observed. On the other hand, hydrophilic yeasts preferentially adsorbed onto relatively hydrophilic surfaces. Moreover, the plate-hanging method coupled with the periodic exchange of the liquid medium enabled the quantification of long-term biofilm growth.}, } @article {pmid36343711, year = {2023}, author = {Wu, B and Ren, Q and Xia, L and Liu, Y and Cui, X and Dai, A and Wei, T and Zhou, Y}, title = {pH-dependent microbial niches succession and antibiotic resistance genes distribution in an oxygen-based membrane biofilm reactor treating greywater.}, journal = {Environmental research}, volume = {216}, number = {Pt 3}, pages = {114725}, doi = {10.1016/j.envres.2022.114725}, pmid = {36343711}, issn = {1096-0953}, mesh = {*Anti-Bacterial Agents/pharmacology ; Waste Disposal, Fluid/methods ; Oxygen/chemistry ; Drug Resistance, Microbial/genetics ; Biofilms ; *Environmental Pollutants ; Hydrogen-Ion Concentration ; Genes, Bacterial ; Wastewater/microbiology ; }, abstract = {System pH is found to crucially affect biofilm growth and microorganisms' activity in the biofilm-based wastewater treatment system. This study investigated the pH-dependent pollutants removal, microbial niches succession and antibiotic resistance genes (ARGs) accumulation in an oxygen-based membrane biofilm reactor treating greywater. Results indicated that neutral conditions achieved the highest biofilm concentration and living cells, which enabled the highest pollutants removal rates; multifarious functional groups in biofilm enabled pollutants adsorption, which favored its continuous bio-removal. Microbial communities under acidic condition (pH = 5.0) were significantly different with that under other conditions (p < 0.05). The neutral and alkaline niches (pH = 7.0 and 9.0) were predominant by organics biodegradation and nitrogen reduction bacteria (e.g. Sphingobacteriales, Pseudomonas, Flavobacterium and Phenylobacterium), but which were significantly dropped under acidic conditions, leading to the declined reactor performance. ARGs in biofilm (predominant by korB, intI-1, sul1 and sul2) were much higher than that in the cell-free liquid and the target ARGs accumulation (korB, intI-1, blaCTX-M, qnrS) had nearly linear positive relationships (R[2] > 0.95, P < 0.01) with biofilm-attached linear alkylbenzene sulfonate (LAS). LAS stimulate ARGs proliferation in functional microorganisms (korB, sul-1 and intI-1 were significantly associated with related microbial genus) and biofilm played a key role in ARGs dissemination. The relatively low ARGs in both biofilm and effluent under neutral conditions suggested that pH controlling can be an effective strategy to inhibit ARGs dissemination and proliferation in the system.}, } @article {pmid36343637, year = {2022}, author = {Schestakow, A and Meyer-Probst, CT and Hannig, C and Hannig, M}, title = {Prevention of Dental Biofilm Formation with Polyphenols: A Systematic Review.}, journal = {Planta medica}, volume = {}, number = {}, pages = {}, doi = {10.1055/a-1939-7615}, pmid = {36343637}, issn = {1439-0221}, abstract = {Polyphenols are plant secondary products with health-promoting properties against various degenerative or infectious diseases, and thus may help in the prevention of oral diseases. The aim of the present systematic review was to investigate polyphenols as a possible adjuvant in inhibiting dental biofilm formation, which is an important precondition for the most prevalent oral disease - caries and periodontitis. A literature search was conducted using the databases PubMed, CENTRAL and Scopus. Only studies with oral healthy participants and plaque level as outcome were included. Data search and extraction was conducted by two authors independently. Of the 211 initially identified studies, only six met all inclusion criteria. Meta-analysis was performed with five studies using the random effect model. Treatment with polyphenols reduced the plaque level in comparison to a negative control, but not significantly. Strong evidence of heterogeneity was observed. The diversity and complexity of polyphenols and their preparation need to be considered. There is no clear evidence that clinical use of polyphenols can prevent dental biofilm formation. Additional research with more and larger randomized controlled trials are required.}, } @article {pmid36342318, year = {2022}, author = {Podnar, E and Erega, A and Danevčič, T and Kovačec, E and Lories, B and Steenackers, H and Mandic-Mulec, I}, title = {Nutrient Availability and Biofilm Polysaccharide Shape the Bacillaene-Dependent Antagonism of Bacillus subtilis against Salmonella Typhimurium.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0183622}, pmid = {36342318}, issn = {2165-0497}, mesh = {Salmonella typhimurium ; Bacillus subtilis ; Biofilms ; *Salmonella enterica ; Nutrients ; *Polyketides/pharmacology ; }, abstract = {Salmonella enterica is one of the most common foodborne pathogens and, due to the spread of antibiotic resistance, new antimicrobial strategies are urgently needed to control it. In this study, we explored the probiotic potential of Bacillus subtilis PS-216 and elucidated the mechanisms that underlie the interactions between this soil isolate and the model pathogenic strain S. Typhimurium SL1344. The results reveal that B. subtilis PS-216 inhibits the growth and biofilm formation of S. Typhimurium through the production of the pks cluster-dependent polyketide bacillaene. The presence of S. Typhimurium enhanced the activity of the PpksC promoter that controls bacillaene production, suggesting that B. subtilis senses and responds to Salmonella. The level of Salmonella inhibition, overall PpksC activity, and PpksC induction by Salmonella were all higher in nutrient-rich conditions than in nutrient-depleted conditions. Although eliminating the extracellular polysaccharide production of B. subtilis via deletion of the epsA-O operon had no significant effect on inhibitory activity against Salmonella in nutrient-rich conditions, this deletion mutant showed an enhanced antagonism against Salmonella in nutrient-depleted conditions, revealing an intricate relationship between exopolysaccharide production, nutrient availability, and bacillaene synthesis. Overall, this work provides evidence on the regulatory role of nutrient availability, sensing of the competitor, and EpsA-O polysaccharide in the social outcome of bacillaene-dependent competition between B. subtilis and S. Typhimurium. IMPORTANCE Probiotic bacteria represent an alternative for controlling foodborne disease caused by Salmonella enterica, which constitutes a serious concern during food production due to its antibiotic resistance and resilience to environmental stress. Bacillus subtilis is gaining popularity as a probiotic, but its behavior in biofilms with pathogens such as Salmonella remains to be elucidated. Here, we show that the antagonism of B. subtilis is mediated by the polyketide bacillaene and that the production of bacillaene is a highly dynamic trait which depends on environmental factors such as nutrient availability and the presence of competitors. Moreover, the production of extracellular polysaccharides by B. subtilis further alters the influence of these factors. Hence, this work highlights the inhibitory effect of B. subtilis, which is condition-dependent, and the importance of evaluating probiotic strains under conditions relevant to the intended use.}, } @article {pmid36341930, year = {2022}, author = {Wang, DY and Yang, G and Zhang, XX and van der Mei, HC and Ren, Y and Busscher, HJ and Shi, L}, title = {Proton-mediated burst of dual-drug loaded liposomes for biofilm dispersal and bacterial killing.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {352}, number = {}, pages = {460-471}, doi = {10.1016/j.jconrel.2022.10.049}, pmid = {36341930}, issn = {1873-4995}, mesh = {Animals ; Mice ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Bromelains ; Ciprofloxacin/pharmacology ; Lipids ; Liposomes ; Microbial Sensitivity Tests ; Polyethylene Glycols ; Protons ; *Sepsis/drug therapy ; }, abstract = {Exposure of infectious biofilms to dispersants induces high bacterial concentrations in blood that may cause sepsis. Preventing sepsis requires simultaneous biofilm dispersal and bacterial killing. Here, self-targeting DCPA(2-(4-((1,5-bis(octadecenoyl)1,5-dioxopentan-2-yl)carbamoyl)pyridin-1-ium-1-yl)acetate) liposomes with complexed water were self-assembled with ciprofloxacin loaded in-membrane and PEGylated as a lipid-membrane component, together with bromelain loaded in-core. Inside biofilms, DCPA-H2O and PEGylated ciprofloxacin became protonated, disturbing the balance in the lipid-membrane to cause liposome-burst and simultaneous release of bromelain and ciprofloxacin. Simultaneous release of bromelain and ciprofloxacin enhanced bacterial killing in Staphylococcus aureus biofilms as compared with free bromelain and/or ciprofloxacin. After tail-vein injection in mice, liposomes accumulated inside intra-abdominal staphylococcal biofilms. Subsequent liposome-burst and simultaneous release of bromelain and ciprofloxacin yielded degradation of the biofilm matrix by bromelain and higher bacterial killing without inducing septic symptoms as obtained by injection of free bromelain and ciprofloxacin. This shows the advantage of simultaneous release from liposomes of bromelain and ciprofloxacin inside a biofilm.}, } @article {pmid36341845, year = {2022}, author = {Sadaqat, MH and Mobarez, AM and Nikkhah, M}, title = {Curcumin carbon dots inhibit biofilm formation and expression of esp and gelE genes of Enterococcusfaecium.}, journal = {Microbial pathogenesis}, volume = {173}, number = {Pt A}, pages = {105860}, doi = {10.1016/j.micpath.2022.105860}, pmid = {36341845}, issn = {1096-1208}, mesh = {Humans ; *Curcumin/pharmacology ; Vancomycin/pharmacology ; Carbon ; Virulence Factors/genetics ; *Enterococcus faecium ; Enterococcus faecalis ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Gram-Positive Bacterial Infections/microbiology ; }, abstract = {The increasing prevalence of vancomycin-resistant Enterococcus faecium, along with the ability of this bacterium to form biofilm on biotic surfaces and medical devices, has created a serious challenge. Therefore, the development of new antibacterial agents is an urgent need. In this study, curcumin carbon dots (Cur-CDs) were synthesized by a one-step hydrothermal method, and its antibacterial and antibiofilm effects were investigated. By broth microdilution method, the minimal inhibitory concentration (MIC) against vancomycin-resistant and sensitive clinical isolates of Enterococcus faecium (two clinical isolates in total) and standard strain of Enterococcus faecalis ATCC 29212 was determined, which were 1000, 1000, and 125 μg/ml, respectively. The inhibitory effect of Cur-CDs on biofilm formation of vancomycin-resistant E. faecium clinical isolates were evaluated by microtiter plate assay. Cur-CDs (1000 μg/ml) significantly prevented (p = 0.009) the biofilm formation of E. faecium isolates. Real-time PCR results showed that Cur-CDs (1000 μg/ml) significantly downregulated the expression of esp and gelE genes (p = 0.001 and p = 000000002, respectively) in clinical isolates of E. faecium, while Cur-CDs did not affect acm gene expression (p = 0.086). This study revealed that Cur-CDs can be effective antibacterial and antibiofilm agents against vancomycin-resistant and biofilm producer E. faecium, which makes them interesting candidates for treating or preventing bacterial infections.}, } @article {pmid36341408, year = {2022}, author = {Xu, T and Zhu, H and Liu, R and Wu, X and Chang, G and Yang, Y and Yang, Z}, title = {The protective role of caffeic acid on bovine mammary epithelial cells and the inhibition of growth and biofilm formation of Gram-negative bacteria isolated from clinical mastitis milk.}, journal = {Frontiers in immunology}, volume = {13}, number = {}, pages = {1005430}, pmid = {36341408}, issn = {1664-3224}, mesh = {Female ; Cattle ; Animals ; Mice ; Humans ; *Milk/metabolism ; *Mastitis, Bovine/microbiology ; Escherichia coli ; Gram-Negative Bacteria ; Epithelial Cells/metabolism ; Bacteria ; Biofilms ; }, abstract = {As a first-line barrier against bacterial infection of mammary tissues, bovine mammary epithelial cells (bMECs) are generally believed to be involved in the immune response due to exogenous stress. Due to the escalating crisis of antibiotic resistance, there is an urgent need for new strategies to combat pathogenic bacteria-infected bovine mastitis. In this study, isolated bMECs and Institute of Cancer Research (ICR) mice were used for Escherichia coli infection and caffeic acid (CA) pretreatment experiments in vitro and in vivo. The inhibitory effect of CA on bacterial growth and biofilm formation was also demonstrated with bacteria strains isolated from mastitis-infected milk. It was demonstrated that CA supplementation prohibits the growth of the predominant strains of bacteria isolated from clinical bovine mastitis milk samples. CA was found to disrupt the biofilm formation of E. coli B1 in a sub-minimum inhibitory concentration (sub-MIC) and inhibited the adherence property of E. coli on bMECs by decreasing the staining of bacteria on cell surfaces in vitro. In addition, CA was found to attenuate proinflammatory and oxidative responses in cells infected with E. coli. The pretreatment of bMECs with CA also restored altered lipid homeostasis caused by E. coli stimulation. The protective role of CA was further confirmed via the administration of CA in mice followed by representative Gram-negative bacterial infection. Collectively, these findings highlight the potential of CA to mediate Gram-negative infections and indicate that it has the potential to be developed as a novel antibacterial drug.}, } @article {pmid36340374, year = {2022}, author = {Lv, M and Ye, S and Hu, M and Xue, Y and Liang, Z and Zhou, X and Zhang, L and Zhou, J}, title = {Two-component system ArcBA modulates cell motility and biofilm formation in Dickeya oryzae.}, journal = {Frontiers in plant science}, volume = {13}, number = {}, pages = {1033192}, pmid = {36340374}, issn = {1664-462X}, abstract = {Phytopathogen Dickeya oryzae is a causal agent of rice foot rot disease and the pathogen has an array of virulence factors, such as phytotoxin zeamines, plant cell wall degrading enzymes, cell motility, and biofilms, collectively contributing to the bacterial pathogenesis. In this study, through deletion analysis of predicted regulatory genes in D. oryzae EC1, we identified a two-component system associated with the regulation of bacterial virulence. The two-component system contains a histidine kinase ArcB and a response regulator ArcA, and deletion of their coding genes resulted in changed phenotypes in cell motility, biofilm formation, and bacterial virulence. Electrophoretic mobility shift assay revealed that ArcA bound to the promoters of the bcs operon and bssS, which respectively encode enzymes for the synthesis of celluloses and a biofilm formation regulatory protein. ArcA could also bind to the promoters of three virulence associated transcriptional regulatory genes, i.e., fis, slyA and ohrR. Surprisingly, although these three regulators were shown to modulate the production of cell wall degrading enzymes and zeamines, deletion of arcB and arcA did not seem to affect these phenotypes. Taken together, the findings from this study unveiled a new two-component system associated with the bacterial pathogenesis, which contributes to the virulence of D. oryzae mainly through its action on bacterial motility and biofilm formation.}, } @article {pmid36339723, year = {2022}, author = {Ciancio Casalini, L and Piazza, A and Masotti, F and Garavaglia, BS and Ottado, J and Gottig, N}, title = {Manganese oxidation counteracts the deleterious effect of low temperatures on biofilm formation in Pseudomonas sp. MOB-449.}, journal = {Frontiers in molecular biosciences}, volume = {9}, number = {}, pages = {1015582}, pmid = {36339723}, issn = {2296-889X}, abstract = {Mn removal from groundwater by biological sand filter technology is negatively impacted by low temperatures in winter periods. Therefore, the need to study Mn(II)-oxidizing bacteria (MOB) having the potential to oxidize Mn(II) and form biofilms at low temperatures is imperative. These MOB can have potential as inocula for sand filter bioaugmentation strategies to optimize Mn removal during winter periods. We previously showed that a Pseudomonas sp. MOB-449 (MOB-449), isolated from a Mn biofilter, oxidizes Mn(II) in a biofilm-dependent way at low temperatures. In this work, MOB-449 Mn(II) oxidation and growth capacities were evaluated under planktonic and biofilm conditions at different temperatures. At 18°C, MOB-449 showed enhanced biofilm formation due to the addition of Mn(II) to the medium correlating with Mn(II) oxidation, compared to biofilms grown in control medium. Moreover, this enhancement on biofilm formation due to the addition of Mn(II) was only observed at 18°C. At this temperature, Mn(II) oxidation in membrane fractions collected from biofilms was induced by uncoupling oxidative phosphorylation from the electron transport chain with 2,4-Dinitrophenol. In Pseudomonas, a role for c-type cytochrome in Mn(II) oxidation has been demonstrated. Accordingly, transcriptional profiles of all terminal oxidases genes found in MOB-449 showed an induction of cytochrome c terminal oxidases expression mediated by Mn(II) oxidation at 18°C. Finally, heme peroxidase activity assays and MS analysis revealed that PetC, a cytochrome c5, and also CcmE, involved in the cytochrome c biogenesis machinery, are induced at 18°C only in the presence of Mn(II). These results present evidence supporting that cytochromes c and also the cytochrome c terminal oxidases are activated at low temperatures in the presence of Mn(II). Overall, this work demonstrate that in MOB-449 Mn(II) oxidation is activated at low temperatures to gain energy, suggesting that this process is important for survival under adverse environmental conditions and contributing to the understanding of the physiological role of bacterial Mn(II) oxidation.}, } @article {pmid36338119, year = {2022}, author = {Liu, Q and Zhu, J and Liu, N and Sun, W and Yu, B and Niu, H and Liu, D and Ouyang, P and Ying, H and Chen, Y and Zhao, G and Chen, T}, title = {Type I fimbriae subunit fimA enhances Escherichia coli biofilm formation but affects L-threonine carbon distribution.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {10}, number = {}, pages = {904636}, pmid = {36338119}, issn = {2296-4185}, abstract = {The biofilm (BF) provides favorable growth conditions to cells, which has been exploited in the field of industrial biotechnology. Based on our previous research works on type I fimbriae for the biosynthesis of L-threonine (LT) in Escherichia coli, in this study, a fimA-overexpressing strain was engineered, which improved BF formation under industrial fermentation conditions. The morphological observation and characterization of BF formation were conducted to verify the function of the subunit FimA. However, it was not suitable for repeated-batch immobilized fermentation as the LT titer was not elevated significantly. The underlying molecular mechanisms of BF formation and the LT carbon flux were explored by transcriptomic analysis. The results showed that fimA regulated E. coli BF formation but affected LT carbon distribution. This study will stimulate thoughts about how the fimbriae gene regulated biofilms and amino acid excretion and will bring some consideration and provide a reference for the development of BF-based biomanufacturing processes in E. coli.}, } @article {pmid36338074, year = {2022}, author = {Liu, X and Xiong, Y and Shi, Y and Deng, X and Deng, Q and Liu, Y and Yu, Z and Li, D and Zheng, J and Li, P}, title = {In vitro activities of licochalcone A against planktonic cells and biofilm of Enterococcus faecalis.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {970901}, pmid = {36338074}, issn = {1664-302X}, abstract = {This study aims to evaluate the in vitro antibacterial and anti-biofilm activities of licochalcone A on Enterococcus faecalis and to investigate the possible target genes of licochalcone A in E. faecalis. This study found that licochalcone A had antibacterial activities against E. faecalis, with the MIC50 and MIC90 were 25 μM. Licochalcone A (at 4 × MIC) indicated a rapid bactericidal effect on E. faecalis planktonic cells, and killed more E. faecalis planktonic cells (at least 3-log10 cfu/ml) than vancomycin, linezolid, or ampicillin at the 2, 4, and 6 h of the time-killing test. Licochalcone A (at 10 × MIC) significantly reduced the production of E. faecalis persister cells (at least 2-log10 cfu/ml) than vancomycin, linezolid, or ampicillin at the 24, 48, 72, and 96 h of the time-killing test. Licochalcone A (at 1/4 × MIC) significantly inhibited the biofilm formation of E. faecalis. The RNA levels of biofilm formation-related genes, agg, esp, and srtA, markedly decreased when the E. faecalis isolates were treated with licochalcone A at 1/4 × MIC for 6 h. To explore the possible target genes of licochalcone A in E. faecalis, the licochalcone A non-sensitive E. faecalis clones were selected in vitro by induction of wildtype strains for about 140 days under the pressure of licochalcone A, and mutations in the possible target genes were detected by whole-genome sequencing. This study found that there were 11 nucleotide mutations leading to nonsynonymous mutations of 8 amino acids, and among these amino acid mutations, there were 3 mutations located in transcriptional regulator genes (MarR family transcriptional regulator, TetR family transcriptional regulator, and MerR family transcriptional regulator). In conclusion, this study found that licochalcone A had an antibacterial effect on E. faecalis, and significantly inhibited the biofilm formation of E. faecalis at subinhibitory concentrations.}, } @article {pmid36336096, year = {2022}, author = {Farto-Vaamonde, X and Diaz-Gomez, L and Parga, A and Otero, A and Concheiro, A and Alvarez-Lorenzo, C}, title = {Perimeter and carvacrol-loading regulate angiogenesis and biofilm growth in 3D printed PLA scaffolds.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {352}, number = {}, pages = {776-792}, doi = {10.1016/j.jconrel.2022.10.060}, pmid = {36336096}, issn = {1873-4995}, mesh = {*Tissue Scaffolds/chemistry ; *Tissue Engineering/methods ; Polyesters/chemistry ; Anti-Bacterial Agents/pharmacology ; X-Ray Microtomography ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Printing, Three-Dimensional ; Biofilms ; }, abstract = {Carvacrol is a natural low-cost compound derived from oregano which presents anti-bacterial properties against both Gram-positive and Gram-negative bacteria. In this work, carvacrol-loaded PLA scaffolds were fabricated by 3D printing as platforms to support bone tissue regeneration while preventing biofilm development. Scaffolds were printed with or without a perimeter (lateral wall) mimicking the cortical structure of bone tissue to further evaluate if the lateral interconnectivity could affect the biological or antimicrobial properties of the scaffolds. Carvacrol incorporation was performed by loading either the PLA filament prior to 3D printing or the already printed PLA scaffold. The loading method determined carvacrol localization in the scaffolds and its release profile. Biphasic profiles were recorded in all cases, but scaffolds loaded post-printed released carvacrol much faster, with 50-80% released in the first day, compared to those containing carvacrol in PLA filament before printing which sustained the release for several weeks. The presence or absence of the perimeter did not affect the release rate, but total amount released. Tissue integration and vascularization of carvacrol-loaded scaffolds were evaluated in a chorioallantoic membrane model (CAM) using a novel quantitative micro-computed tomography (micro-CT) analysis approach. The obtained results confirmed the CAM tissue ingrowth and new vessel formation within the porous structure of the scaffolds after 7 days of incubation, without leading to hemorrhagic or cytotoxic effects. The absence of lateral wall facilitated lateral integration of the scaffolds in the host tissue, although increased the anisotropy of the mechanical properties. Scaffolds loaded with carvacrol post-printing showed antibiofilm activity against Staphylococcus aureus and Pseudomonas aeruginosa as observed in a decrease in CFU counting after biofilm detachment, changes in metabolic heat measured by calorimetry, and increased contact killing efficiency. In summary, this work demonstrated the feasibility of tuning carvacrol release rate and the amount released from PLA scaffolds to achieve antibiofilm protection without altering angiogenesis, which was mostly dependent on the perimeter density of the scaffolds.}, } @article {pmid36335891, year = {2023}, author = {Duc, HM and Zhang, Y and Son, HM and Huang, HH and Masuda, Y and Honjoh, KI and Miyamoto, T}, title = {Genomic characterization and application of a novel bacteriophage STG2 capable of reducing planktonic and biofilm cells of Salmonella.}, journal = {International journal of food microbiology}, volume = {385}, number = {}, pages = {109999}, doi = {10.1016/j.ijfoodmicro.2022.109999}, pmid = {36335891}, issn = {1879-3460}, mesh = {*Salmonella Phages/genetics ; *Bacteriophages/genetics ; Plankton/genetics ; Salmonella enteritidis ; Biofilms ; Genomics ; }, abstract = {As one major foodborne pathogen, Salmonella can cause serious food poisoning outbreaks worldwide. Bacteriophage therapy is increasingly considered as one of the promising antibacterial agents for the biocontrol of foodborne pathogens. In the current study, a lytic phage STG2 capable of infecting S. enteritidis and S. typhimurium was characterized, and its efficacy in reducing these foodborne pathogens in both planktonic and biofilm forms was evaluated on cabbage and various surfaces. Genomic characterization revealed that phage STG2 was Siphoviridae phage (Epseptimavirus genus) with a dsDNA genome comprising of 114,275 bp and its genome does not contain any genes associated to antibiotic resistance, toxins, lysogeny, or virulence factors. Additionally, phage STG2 exhibited great efficacy in reducing (>2 Log) planktonic cells on cabbage as well as the biofilms formed on cabbage, polystyrene, and stainless steel, suggesting that phage STG2 is capable of simultaneously controlling both S. enteritidis and S. typhimurium contaminations on food and food-related surfaces.}, } @article {pmid36334202, year = {2023}, author = {Tian, L and Wang, L and Zhang, X and Huang, X and Wang, F and Zhu, S and Li, X and Guan, Y}, title = {Multi-omics analysis on seasonal variations of the biofilm microbial community in a full-scale pre-denitrification biofilter.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {9}, pages = {24284-24298}, pmid = {36334202}, issn = {1614-7499}, support = {21-1-4-sf-11-nsh//science and technology program for public wellbeing of qingdao/ ; }, mesh = {*Denitrification ; Bioreactors/microbiology ; Seasons ; Multiomics ; Proteomics ; *Microbiota ; Biofilms ; Nitrogen ; }, abstract = {The seasonal variations of biofilm communities in a municipal wastewater treatment plant were investigated using multi-omics techniques. The abundance of the main phyla of microorganisms varied with summer (July 2019) and winter (January 2019) samples considerably, the Bacteroidetes enriched in winter and Chloroflexi in summer. The results of metaproteomic and metagenomic showed that most of the functional microorganisms belonged to the Betaproteobacteria class, and the enrichment of Flavobacteria class in winter guaranteed the stability of denitrification performance to some extent. Seasonal variations affected the proteomic expression profiling, a total of 2835 differentially expressed proteins identified were significantly enriched in quorum sensing, two-component system, ribosome, benzoate degradation, butanoate metabolism, tricarboxylic acid cycle (TCA cycle), and cysteine and methionine metabolism pathways. With the expression of nitrogen metabolic proteins decreases in winter, the overall expression of denitrification-related enzymes in winter was much lower than that in summer, the nitrogen metabolism pathway varied significantly. Seasonal variations also induced the alteration of the biofilm metabolite profile; a total of 66 differential metabolites, 8 potential biomarkers, and 8 perturbed metabolic pathways such as TCA cycle were detected. It was found that most of the perturbed pathways are directly related to nitrogen metabolism, and several amino acids and organic acids associated with the TCA cycle were significantly perturbed, the accumulation of TCA cycle intermediates, ornithine, and L-histidine in winter might be conducive to resisting cold temperatures. Furthermore, the correlation between biofilm microbial communities and metabolites was identified by the combined analysis of metabolomic and metaproteomic. The differences of microbial community structure, function, and metabolism between winter and summer in a full-scale pre-denitrification biofilter were revealed for the first time, strengthening our understanding of the microbial ecology of biofilm communities.}, } @article {pmid36333517, year = {2022}, author = {Cho, JA and Roh, YJ and Son, HR and Choi, H and Lee, JW and Kim, SJ and Lee, CH}, title = {Assessment of the biofilm-forming ability on solid surfaces of periprosthetic infection-associated pathogens.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {18669}, pmid = {36333517}, issn = {2045-2322}, support = {KMDF_PR_20200901_0082, 9991006755//Korea Medical Device Development Fund grant (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety)/ ; }, mesh = {Humans ; *Biofilms ; Bacterial Adhesion ; Staphylococcus aureus ; Enterococcus faecalis ; *Staphylococcal Infections ; Polystyrenes ; }, abstract = {Biofilm formation is one of the leading causes of complications after surgery in clinical settings. In this study, we profiled the biofilm-forming ability of various periprosthetic infection-associated pathogens on medically relevant surfaces, polystyrene (PS) and titanium (Ti). We also explored how a specific environmental stressor, epigallocatechin gallate (EGCG), affected biofilm formation. First, Congo red tests revealed that all microorganisms formed biofilms within 72 h. Then, the amounts of biofilm formation on PS at 24, 48 and 72 h and also on a Ti plate for 72 h were determined. Some microbes preferred one surface over the other, whereas other microbes formed consistent levels of biofilm regardless of the surface material. Staphylococcus lugdunenensis was the most potent, while Enterococcus faecalis and Staphylococcus aureus were the weakest. Bacterial adhesion to hydrocarbon (BATH) tests indicated that the biofilm-forming abilities were not directly correlated with cell surface hydrophobicity (CSH). Finally, an external signal, EGCG, was applied to challenge the biofilm formation of each microorganism. EGCG regulated each microorganism's ability differently, though the change was consistent across surfaces for most pathogens. This study can help a better understanding of a broad spectrum of periprosthetic infection-associated pathogens by relative comparison of their biofilm-forming abilities.}, } @article {pmid36330326, year = {2022}, author = {Charlton, SGV and Kurz, DL and Geisel, S and Jimenez-Martinez, J and Secchi, E}, title = {The role of biofilm matrix composition in controlling colony expansion and morphology.}, journal = {Interface focus}, volume = {12}, number = {6}, pages = {20220035}, pmid = {36330326}, issn = {2042-8898}, abstract = {Biofilms are biological viscoelastic gels composed of bacterial cells embedded in a self-secreted polymeric extracellular matrix (ECM). In environmental settings, such as in the rhizosphere and phyllosphere, biofilm colonization occurs at the solid-air interface. The biofilms' ability to colonize and expand over these surfaces depends on the formation of osmotic gradients and ECM viscoelastic properties. In this work, we study the influence of biofilm ECM components on its viscoelasticity and expansion, using the model organism Bacillus subtilis and deletion mutants of its three major ECM components, TasA, EPS and BslA. Using a multi-scale approach, we quantified macro-scale viscoelasticity and expansion dynamics. Furthermore, we used a microsphere assay to visualize the micro-scale expansion patterns. We find that the viscoelastic phase angle Φ is likely the best viscoelastic parameter correlating to biofilm expansion dynamics. Moreover, we quantify the sensitivity of the biofilm to changes in substrate water potential as a function of ECM composition. Finally, we find that the deletion of ECM components significantly increases the coherence of micro-scale colony expansion patterns. These results demonstrate the influence of ECM viscoelasticity and substrate water potential on the expansion of biofilm colonies on wet surfaces at the air-solid interface, commonly found in natural environments.}, } @article {pmid36330094, year = {2022}, author = {Zhang, Y and Wang, Y and Zhao, X and Liu, L and Xing, R and Song, X and Zou, Y and Li, L and Wan, H and Jia, R and Yin, L and Liang, X and He, C and Wei, Q and Yin, Z}, title = {Study on the anti-biofilm mechanism of 1,8-cineole against Fusarium solani species complex.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {1010593}, pmid = {36330094}, issn = {1663-9812}, abstract = {Fungal-infections are mostly due to fungi in an adhering, biofilm-mode of growth and not due to planktonically growing, suspended-fungi. 1, 8-cineole is a natural product, which has been shown to possess antifungal effect. However, the anti-biofilm effect and mechanism of 1,8-cineole against Fusarium solani species complex has not reported previously. In this study, we found that 1,8-cineole has a good antifungal activity against F. solani with an MIC value of 46.1 μg/ml. Notably, 1,8-cineole showed good anti-biofilm formation activity against F. solani via inhibiting cell adhesion, hypha formation and decreasing the secretion of extracellular matrix at the concentration of ≥5.76 μg/ml. In addition, transcriptome sequencing analysis results showed that F. solani species complex genes related to ECM, protein synthesis and energy metabolism were down-expressed in the biofilms formation process treated with 1,8-cineole. In conclusion, these results show that 1,8-cineole has good anti-biofilm formation activity against F. solani species complex, and it exerts its anti-biofilm formation activity by downregulating of ergosterol biosynthetic genes, inhibiting adhesion, hindering the synthesis of ECM and interfering mitochondrial activity. This study suggests that 1,8-cineole is a promising anti-biofilm agent against F. solani species complex.}, } @article {pmid36330093, year = {2022}, author = {Wang, Y and Zhang, Y and Song, X and Fang, C and Xing, R and Liu, L and Zhao, X and Zou, Y and Li, L and Jia, R and Ye, G and Shi, F and Zhou, X and Zhang, Y and Wan, H and Wei, Q and Yin, Z}, title = {1,8-Cineole inhibits biofilm formation and bacterial pathogenicity by suppressing luxS gene expression in Escherichia coli.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {988245}, pmid = {36330093}, issn = {1663-9812}, abstract = {In recent years, with frequent reports of multi-drug resistant strains, bacteria antibiotic resistance has become an increasingly serious health problem worldwide. One of the most promising ways for combating bacterial infections and antibiotic resistance is development of quorum-sensing (QS) interfering drugs. In this study, the results show that 1,8-cineole inhibited the expression of QS as well as the virulence genes in Escherichia coli O101 (E. coli O101) with a 65% inhibition rate against luxS gene. Therefore, we hypothesized that 1,8-cineole may inhibit the biofilm formation and reduce the pathogenicity of E. coli O101 by inhibiting the expression of luxS gene. To confirm our hypotheses, a luxS gene deleted E. coli O101 was constructed. The results show that the biofilm formation, motility, structure and pathogenicity of E. coli O101 were significantly inhibited following deletion of the luxS gene. In addition, the transcript levels of QS and virulence genes of E. coli O101 were also significantly down-regulated. Interestingly, 1,8-cineole no longer had a significant inhibitory effect on the related phenotype and gene expression of E. coli O101 without luxS gene. In conclusion, the results show that 1,8-cineole can affect bacterial biofilm formation and pathogenicity by suppressing the expression of luxS gene in E. coli O101, which could provide a new perspective for dealing with the biofilm problem of pathogenic bacteria.}, } @article {pmid36329896, year = {2022}, author = {Pajohesh, R and Tajbakhsh, E and Momtaz, H and Rahimi, E}, title = {Relationship between Biofilm Formation and Antibiotic Resistance and Adherence Genes in Staphylococcus aureus Strains Isolated from Raw Cow Milk in Shahrekord, Iran.}, journal = {International journal of microbiology}, volume = {2022}, number = {}, pages = {6435774}, pmid = {36329896}, issn = {1687-918X}, abstract = {The production of biofilms by S. aureus contributes significantly to treatment failures. The present study aims to establish the relationship between biofilm formation and antibiotic resistance and adhesion genes in Staphylococcus aureus strains isolated from raw cow milk in Shahrekord, Iran. A total of 90 samples of raw cow's milk were collected. Presumptive S. aureus strains were obtained using Baird-Parker plates after enrichment in tryptone soy broth, and final colonies were selected from brain heart infusion. Additional tests such as coagulase were done, and the identification was confirmed by the detection of the aroA gene. Biofilm producing strains were screened using a spectrophotometry method applied to microplates. Crystal violet staining was used to quantify the formation of biofilm. An antibiotic susceptibility test was performed using the Kirby-Bauer disc diffusion method. PCR was used to detect several biofilm and antibiotics resistance related genes. The chi-square test and Fisher's exact test were used to establish a statistically significant relationship between biofilm reaction and antibiotic resistance (p value <0.05). Results show a moderate (38.88%) recovery rate of S. aureus in milk and 65.71% of the isolates were strong biofilm producers. Antibiotic susceptibility tests show an alarming rate of resistance to beta-lactam antibiotics, especially penicillin (100%), ampicillin (91.42%), and oxacillin (71.42%). This finding correlates with antibiotic resistance gene detection, in which the gene blaZ was most found (71.42%), followed by mecA and Aac-D (42.85%). Detection of biofilm-related genes shows that all the genes targeted were found among S. aureus isolates. Statistical tests show a significant correlation between biofilm production and antibiotic resistance in S. aureus. This study revealed that there is a significant correlation between biofilm production and antibiotic resistance in S. aureus isolated from raw milk. These results highlight the need for regular surveillance of the occurrence of S. aureus strains in milk and milk products in Iran.}, } @article {pmid36329825, year = {2022}, author = {Ravichandran, S and Avatapalli, S and Narasimhan, Y and Kaushik, KS and Yennamalli, RM}, title = {'Targeting' the search: An upgraded structural and functional repository of antimicrobial peptides for biofilm studies (B-AMP v2.0) with a focus on biofilm protein targets.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1020391}, pmid = {36329825}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology/chemistry ; *Antimicrobial Cationic Peptides/pharmacology ; *Antimicrobial Peptides ; Bacteria ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {Bacterial biofilms, often as multispecies communities, are recalcitrant to conventional antibiotics, making the treatment of biofilm infections a challenge. There is a push towards developing novel anti-biofilm approaches, such as antimicrobial peptides (AMPs), with activity against specific biofilm targets. In previous work, we developed Biofilm-AMP, a structural and functional repository of AMPs for biofilm studies (B-AMP v1.0) with more than 5000 structural models of AMPs and a vast library of AMP annotations to existing biofilm literature. In this study, we present an upgraded version of B-AMP, with a focus on existing and novel bacterial biofilm targets. B-AMP v2.0 hosts a curated collection of 2502 biofilm protein targets across 473 bacterial species, with structural protein models and functional annotations from PDB, UniProt, and PubMed databases. The biofilm targets can be searched for using the name of the source organism, and function and type of protein, and results include designated Target IDs (unique to B-AMP v2.0), UniProt IDs, 3D predicted protein structures, PDBQT files, pre-defined protein functions, and relevant scientific literature. To present an example of the combined applicability of both, the AMP and biofilm target libraries in the repository, we present two case studies. In the first case study, we expand an in silico pipeline to evaluate AMPs against a single biofilm target in the multidrug resistant, bacterial pathogen Corynebacterium striatum, using 3D protein-peptide docking models from previous work and Molecular Dynamics simulations (~1.2µs). In the second case study, we build an in silico pipeline to identify candidate AMPs (using AMPs with both anti-Gram positive and anti-Gram negative activity) against two biofilm targets with a common functional annotation in Pseudomonas aeruginosa and Staphylococcus aureus, widely-encountered bacterial co-pathogens. With its enhanced structural and functional capabilities, B-AMP v2.0 serves as a comprehensive resource for AMP investigations related to biofilm studies. B-AMP v2.0 is freely available at https://b-amp.karishmakaushiklab.com and will be regularly updated with structural models of AMPs and biofilm targets, as well as 3D protein-peptide interaction models for key biofilm-forming pathogens.}, } @article {pmid36329688, year = {2021}, author = {Jin, X and An, S and Kightlinger, W and Zhou, J and Hong, SH}, title = {Engineering Escherichia coli to produce and secrete colicins for rapid and selective biofilm cell killing.}, journal = {AIChE journal. American Institute of Chemical Engineers}, volume = {67}, number = {12}, pages = {}, pmid = {36329688}, issn = {0001-1541}, support = {R15 AI130988/AI/NIAID NIH HHS/United States ; }, abstract = {Bacterial biofilms are associated with chronic infectious diseases and are highly resistant to conventional antibiotics. Antimicrobial bacteriocins are alternatives to conventional antibiotics and are characterized by unique cell-killing mechanisms, including pore formation on cell membranes, nuclease activity, and cell wall synthesis inhibition. Here, we used cell-free protein synthesis to rapidly evaluate the anti-biofilm activities of colicins E1, E2, and E3. We found that E2 (with DNase activity) most effectively killed target biofilm cells (i.e., the K361 strain) while leaving non-targeted biofilms intact. We then engineered probiotic Escherichia coli microorganisms with genetic circuits to controllably synthesize and secrete colicin E2, which successfully inhibited biofilms and killed pre-formed indicator biofilms. Our findings suggest that colicins rapidly and selectively kill target biofilm cells in multispecies biofilms and demonstrate the potential of using microorganisms engineered to produce antimicrobial colicin proteins as live therapeutic strategies to treat biofilm-associated infections.}, } @article {pmid36329103, year = {2022}, author = {Wiguna, OD and Waturangi, DE and Yogiara, }, title = {Bacteriophage DW-EC with the capability to destruct and inhibit biofilm formed by several pathogenic bacteria.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {18539}, pmid = {36329103}, issn = {2045-2322}, mesh = {*Bacteriophages ; Polystyrenes ; Biofilms ; *Enteropathogenic Escherichia coli/physiology ; *Enterohemorrhagic Escherichia coli ; Bacteria ; *Enterotoxigenic Escherichia coli ; Stainless Steel/pharmacology ; }, abstract = {Biofilm formation by pathogenic bacteria is a major challenge in the food industry. Once a biofilm is established, such as on food processing equipment, it becomes more difficult to eradicate. Although physical and chemical treatments are often used to control biofilm formation, these treatments can have significant drawbacks. Alternative biofilm treatments are needed. Phage DW-EC was isolated from dawet, an Indonesian traditional Ready-To-Eat food, which has high specificity for Enterohaemorrhagic Escherichia coli (EHEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC). Phage DW-EC produces several enzymes that can prevent the development of biofilm and biofilm eradication. Depolymerase enzymes break down the polysaccharides layer on the biofilms can lead to biofilm damage. On the other hand, endolysin and putative like-T4 lysozyme will lyse and kill a bacterial cell, thereby preventing biofilm growth. This research aims to determine the capability of previously identified phage DW-EC to inhibit and destroy biofilms produced by several foodborne pathogens. Phage DW-EC formed plaques on the bacterial lawns of EHEC, EPEC, and ETEC. The efficiency of plating (EOP) values for EHEC, EPEC, ETEC, and Bacillus cereus were 1.06, 0.78. 0.70, and 0.00, demonstrating that DW-EC was effective in controlling pathogenic E. coli populations. Furthermore, phage DW-EC showed anti-biofilm activity against foodborne pathogenic bacteria on polystyrene and stainless-steel substrates. DW-EC biofilm inhibition and destruction activities against pathogenic E. coli were significantly higher than against B. cereus biofilms, which was indicated by a lower density of the biofilm than B. cereus. Microscopic visualization verified that bacteriophage DW-EC effectively controlled EHEC, EPEC, and ETEC biofilms. The results showed that DW-EC could inhibit and destroy biofilm, making it promising to be used as an anti-biofilm candidate for polystyrene and stainless steel equipment in the food industry.}, } @article {pmid36327929, year = {2022}, author = {Surya, T and Jeyasekaran, G and Shakila, RJ and Sivaraman, B and Shalini, R and Sundhar, S and Arisekar, U}, title = {Prevalence of biofilm forming Salmonella in different seafood contact surfaces of fishing boats, fish landing centres, fish markets and seafood processing plants.}, journal = {Marine pollution bulletin}, volume = {185}, number = {Pt A}, pages = {114285}, doi = {10.1016/j.marpolbul.2022.114285}, pmid = {36327929}, issn = {1879-3363}, mesh = {Animals ; *Ships ; *Bacterial Adhesion ; Prevalence ; Hunting ; Biofilms ; Salmonella ; Seafood ; }, abstract = {The prevalence of biofilm forming Salmonella on different seafood contact surfaces was investigated. Out of 384 swab samples, 16.14 % and 1 % were confirmed biochemically and molecularly as Salmonella respectively. One out of four isolates was from the boat deck, and three were from the seafood processing plant. Salmonella was more prevalent in January, June, and September months. Different assays investigated the biofilm forming ability of isolates. Two out of four isolates have shown strong biofilms, and the others were moderate biofilm formers by microtitre plate assay. In the CRA assay, three isolates showed 'rdar' morphotype, and one showed 'bdar' morphotype. All isolates were positive for gcpA gene (~1700 bp), a critical gene found in Salmonella biofilms. The microbial load of Salmonella biofilms on different contact surfaces were determined, stainless steel and HDPE were found prone to biofilms. With this, a suitable mechanism shall be formulated to control the biofilms of Salmonella.}, } @article {pmid36327008, year = {2023}, author = {Naziri, Z and Majlesi, M}, title = {Comparison of the prevalence, antibiotic resistance patterns, and biofilm formation ability of methicillin-resistant Staphylococcus pseudintermedius in healthy dogs and dogs with skin infections.}, journal = {Veterinary research communications}, volume = {47}, number = {2}, pages = {713-721}, pmid = {36327008}, issn = {1573-7446}, support = {99GCB1M344385//Shiraz University/ ; }, mesh = {Dogs ; Animals ; Methicillin Resistance ; *Methicillin-Resistant Staphylococcus aureus ; Prevalence ; Anti-Bacterial Agents/pharmacology ; *Dog Diseases/drug therapy/epidemiology ; *Staphylococcal Infections/drug therapy/epidemiology/veterinary ; Microbial Sensitivity Tests/veterinary ; }, abstract = {Staphylococcus pseudintermedius (S. pseudintermedius), found on dogs' skin and mucous membranes, can act as an opportunistic pathogen causing skin, ear, and other tissue infections. Due to the possibility of zoonotic transmission of them, it is necessary to investigate the prevalence of S. pseudintermedius, especially the antimicrobial-resistant strains, in pets. In this study, the prevalence, antimicrobial resistance patterns, and biofilm formation ability of methicillin-resistant S. pseudintermedius (MRSP) were investigated and compared in 50 healthy dogs and 50 dogs with skin infections. The prevalence of S. pseudintermedius was not significantly different between healthy dogs (40%) and dogs with skin infections (50%). No significant difference was found in the prevalence of MRSP between healthy dogs (12%) and dogs with skin infections (18%). A total of 81.8% of S. pseudintermedius isolates were biofilm producers. The frequencies of antibiotic resistance (except for gentamicin), multidrug resistance (MDR), and biofilm formation ability were not significantly different between S. pseudintermedius isolates of healthy dogs and dogs with skin infections. The frequencies of resistance to penicillin and tetracycline, MDR, and biofilm production abilities were significantly higher among MRSP than methicillin-susceptible S. pseudintermedius (MSSP). The frequency of oxacillin resistance was significantly higher among weak or moderate biofilm producers than non-biofilm producers. The frequency of resistance to erythromycin was significantly higher among moderate biofilm producers than non-biofilm producers or weak biofilm producers. High frequencies of biofilm-producer S. pseudintermedius isolates and their resistance to antibiotics can affect the success of treatment of infections caused by these strains.}, } @article {pmid36326671, year = {2022}, author = {Holden, ER and Yasir, M and Turner, AK and Charles, IG and Webber, MA}, title = {Comparison of the genetic basis of biofilm formation between Salmonella Typhimurium and Escherichia coli.}, journal = {Microbial genomics}, volume = {8}, number = {11}, pages = {}, pmid = {36326671}, issn = {2057-5858}, support = {BB/R012504/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Salmonella typhimurium/genetics ; *Escherichia coli/genetics ; Biofilms ; Flagella/genetics ; Bacteria ; }, abstract = {Most bacteria can form biofilms, which typically have a life cycle from cells initially attaching to a surface before aggregation and growth produces biomass and an extracellular matrix before finally cells disperse. To maximize fitness at each stage of this life cycle and given the different events taking place within a biofilm, temporal regulation of gene expression is essential. We recently described the genes required for optimal fitness over time during biofilm formation in Escherichia coli using a massively parallel transposon mutagenesis approach called TraDIS-Xpress. We have now repeated this study in Salmonella enterica serovar Typhimurium to determine the similarities and differences in biofilm formation through time between these species. A core set of pathways involved in biofilm formation in both species included matrix production, nucleotide biosynthesis, flagella assembly and LPS biosynthesis. We also identified several differences between the species, including a divergent impact of the antitoxin TomB on biofilm formation in each species. We observed deletion of tomB to be detrimental throughout the development of the E. coli biofilms but increased biofilm biomass in S. Typhimurium. We also found a more pronounced role for genes involved in respiration, specifically the electron transport chain, on the fitness of mature biofilms in S. Typhimurium than in E. coli and this was linked to matrix production. This work deepens understanding of the core requirements for biofilm formation in the Enterobacteriaceae whilst also identifying some genes with specialised roles in biofilm formation in each species.}, } @article {pmid36324525, year = {2022}, author = {Guillaume, O and Butnarasu, C and Visentin, S and Reimhult, E}, title = {Interplay between biofilm microenvironment and pathogenicity of Pseudomonas aeruginosa in cystic fibrosis lung chronic infection.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100089}, pmid = {36324525}, issn = {2590-2075}, abstract = {Pseudomonas aeruginosa (PA) is a highly, if not the most, versatile microorganism capable of colonizing diverse environments. One of the niches in which PA is able to thrive is the lung of cystic fibrosis (CF) patients. Due to a genetic aberration, the lungs of CF-affected patients exhibit impaired functions, rendering them highly susceptible to bacterial colonization. Once PA attaches to the epithelial surface and transitions to a mucoid phenotype, the infection becomes chronic, and antibiotic treatments become inefficient. Due to the high number of affected people and the severity of this infection, CF-chronic infection is a well-documented disease. Still, numerous aspects of PA CF infection remain unclear. The scientific reports published over the last decades have stressed how PA can adapt to CF microenvironmental conditions and how its surrounding matrix of extracellular polymeric substances (EPS) plays a key role in its pathogenicity. In this context, it is of paramount interest to present the nature of the EPS together with the local CF-biofilm microenvironment. We review how the PA biofilm microenvironment interacts with drugs to contribute to the pathogenicity of CF-lung infection. Understanding why so many drugs are inefficient in treating CF chronic infection while effectively treating planktonic PA is essential to devising better therapeutic targets and drug formulations.}, } @article {pmid36323351, year = {2023}, author = {Huang, Y and Zhang, B and Chen, K and Xia, A and Zhu, X and Zhu, X and Liao, Q}, title = {Temperature-controlled microalgae biofilm adsorption/desorption in a thermo-responsive light-guided 3D porous photo-bioreactor for CO2 fixation.}, journal = {Environmental research}, volume = {216}, number = {Pt 3}, pages = {114645}, doi = {10.1016/j.envres.2022.114645}, pmid = {36323351}, issn = {1096-0953}, mesh = {*Microalgae ; Carbon Dioxide ; Adsorption ; Temperature ; Porosity ; Silicon Dioxide ; Photobioreactors ; Biofilms ; Hydrogels ; Biomass ; }, abstract = {Microalgae biofilm-based culture provides an efficient CO2 reduction and wastewater treatment method for its high photosynthetic efficiency and density. As supporting substrates for microalgae biofilm, porous materials have a big available adsorption area, but mutual shading makes it difficult to transmit external light to the internal surface for attached cells' photosynthesis. Thus, light-guided particles (SiO2) were introduced into photosensitive resin to fabricate a light-guided ordered porous photobioreactor (PBR) by 3D printing technology in this study. The space utilization of the PBR was significantly enhanced and the effective microalgae adsorption area was increased by 13.6 times. Further, a thermo-responsive hydrogel was grafted onto the surface of the substrate to form a smart temperature-controllable interface that could enhance microalgae adsorption and desorption in both directions. When the thermo-responsive layer received light, it would generate heat due to the hydrogel's photo-thermal effect. And the surface temperature would then raise to 33 °C, higher than the hydrogel phase transition point of 32 °C, making the surface shrinking and more hydrophobicity for microalgae cells attachment. The microalgae cells' adsorption capacity increased by 103%, resulting in a high microalgae growth rate of 3.572 g m[-2] d[-1]. When turning off the light, the surface temperature would cool down to below 20 °C, the surface would shrink. And the biofilm shows a 564.7% increase in desorption ability, realizing temperature-controlled microalgae harvesting.}, } @article {pmid36321648, year = {2023}, author = {Chackartchi, T and Zaydel, L and Shapira, L and Shany-Kdoshim, S and Polak, D}, title = {Biofilm formation, its removal, and consequent effect on the osteoblast response to titanium surfaces: A model for re-osseointegration.}, journal = {Journal of periodontology}, volume = {94}, number = {3}, pages = {419-428}, doi = {10.1002/JPER.22-0142}, pmid = {36321648}, issn = {1943-3670}, mesh = {Humans ; *Titanium/pharmacology ; *Osseointegration ; Alkaline Phosphatase/metabolism ; Biofilms ; Osteoblasts/metabolism ; Inflammation ; Anti-Bacterial Agents/pharmacology ; Surface Properties ; }, abstract = {BACKGROUND: The aim of the study was to characterize pathogenic biofilm formation on titanium surfaces, the ability to remove the biofilm and the osteoblast response to infected and cleaned titanium surfaces as a model for re-osseointegration.

METHODS: Multispecies biofilm composed of Pseudomonas. gingivalis, F. nucleatum, S. sanguis, and A. naeslundii were grown on smooth, acid-etched, and acid-etched-aluminum-sprayed titanium surfaces. Bacterial viability was determined with live/dead staining. The biofilm was removed mechanically or together with adjunctive antibiotics. The osteoblast (Saos2) response to previously infected, treated and non-infected titanium surfaces were measured according to 4'-6-diamidino-2-phenylindole staining. Alkaline phosphatase levels and receptor activator of nuclear factor kappa-Β ligand/osteoprotegerin expression were measured with enzyme-linked immunosorbent assay and immunofluorescence staining, respectively The inflammatory environment was established by using differentiated HL-60 cells (neutrophils) pre-inoculated onto the biofilm clusters that were more prominent and less scattered on infected titanium surfaces before osteoblast attachment.

RESULTS: Biofilm formed on all the tested surfaces, with an increased thickness on rough surfaces and no differences in bacterial viability. All the treatments reduced the amount of biofilm, but none led to bacteria-free surfaces. The treated surfaces showed reduced osteoblast attachment and reduced alkaline phosphatase activity compared with non-infected surfaces. Additionally, treated surfaces showed an osteoblast shift to a pro-osteoclastic-induction phenotype, compared with non-infected surfaces. The presence of experimental inflammation before osteoblast attachment reduced the levels of osteoblast attachment compared with that of the non-inflamed control.

CONCLUSIONS: Biofilm removal from titanium surfaces is incomplete when hand instruments are used alone or in combination with antibiotics. The treated surfaces showed impaired osteoblast attachment and function, particularly in the presence of inflammation, which may prevent or decrease the ability for re-osseointegration.}, } @article {pmid36315853, year = {2022}, author = {Mazioti, AA and Vyrides, I}, title = {Treatment of high-strength saline bilge wastewater by four pilot-scale aerobic moving bed biofilm reactors and comparison of the microbial communities.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/09593330.2022.2137436}, pmid = {36315853}, issn = {1479-487X}, abstract = {Four Pilot-scale Moving Bed Biofilm Reactors (MBBRs) were operated for the treatment of real, saline, bilge wastewater. The MBBRs were connected in pairs to create two system configurations with different filling ratios (20%, 40%) and were operated in parallel. The inflow organic loading rate (OLR) varied from 3.6 ± 0.2 to 7.8 ± 0.6 g COD L[-1] d[-1], salinity was >15 ppt and three hydraulic residence times (HRTs) were tested 48, 30 and 24 h. In both systems, the first-stage bioreactors (R1 and R3) eliminated the higher part of the organic load (57%-65%). The second-stage bioreactors (R2 and R4) removed an additional fraction (18%-31%) of the organic load received by the effluent of R1 and R3, respectively. The microbial communities of the influent wastewater, suspended, and attached biomass were determined using 16S rRNA gene amplicon sequencing analysis. The evolution of the microbial communities was investigated and compared over the different operational phases. The microbial communities of the biofilm presented higher diversity and greater stability in composition over time, while the suspended biomass exhibited intense and rapid changes in the dominance of genera. Proteobacteria, Bacteroidetes and Firmicutes were highly present in the biofilm. The genera Celeribacter, Novispirillum, Roseovarius (class: Alphaproteobacteria) and Formosa (class: Flavobacteriia) were highly present during all operational phases. Principal Component Analysis (PCA) was used to identify similarities between samples, exhibiting high relation of samples according to the series of the bioreactor (1st, 2nd).}, } @article {pmid36315175, year = {2022}, author = {Shipitsyna, IV and Osipova, EV}, title = {Influence of ß-lactam antibiotics on the activity of K. pneumoniae bacteria biofilm forms isolated from wounds of patients with chronic osteomyelitis.}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {67}, number = {10}, pages = {594-599}, doi = {10.51620/0869-2084-2022-67-10-594-599}, pmid = {36315175}, issn = {0869-2084}, mesh = {Humans ; Microbial Sensitivity Tests ; Cefepime/pharmacology ; *Polystyrenes/pharmacology ; Klebsiella pneumoniae ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Osteomyelitis/drug therapy ; Monobactams/pharmacology ; Bacteria ; Imipenem/pharmacology/therapeutic use ; }, abstract = {One of the reasons for the emergence of highly resistant strains is associated with the ability of bacteria to form biofilms on various surfaces. The formation of a biofilm by pathogens leads to a decrease in the activity of the antibiotic, an increase in the time for the production of stress response genes by bacteria, and, as a result, an increase in antimicrobial tolerance. To investigate the effect of imipenem and cefepime on the activity of biofilm forms of K. pneumoniae bacteria isolated from the wounds of patients with chronic osteomyelitis. The object of the study is clinical strains of K. pneumoniae isolated from the wounds of patients with chronic osteomyelitis. In the control series, the level of biofilm formation of K. pneumoniae strains was assessed after 48 hours of cultivation on coverslips and 96-well polystyrene plates. In the second and third series, the biofilm form of K. pneumoniae bacteria was exposed to imipenem and cefepime, and after 24 hours the activity of biofilm formation was assessed according to previously developed criteria. The structure of the emerging biofilm on the surface of the coverslip in all series of the experiment was represented by single adherent cells and microcolonies of various sizes. Cultivation with antibiotics led to a decrease in the number of microcolonies ranging in size from 10 to 10,000 µm2 in the second and third series, however, significant differences from the control series were found only when exposed to cefepime. The intensity of film formation of K. pneumoniae in the control series by the tablet method was 0.350 (0.334; 0.368) units opt.pl. When cultivating biofilms together with antibacterial drugs, the biofilm-forming activity after 24 hours of the experiment was significantly lower than in the control group in all experimental series. K. pneumoniae bacteria isolated from patients with chronic osteomyelitis, when cultivated on polystyrene plates and on the surface of coverslips, actively form a biofilm, exhibiting highly adhesive properties. The studied antibiotics were shown to have a bacteriostatic effect on biofilm forms of K. pneumoniae bacteria. The bactericidal effect of imipenem and cefepime on biofilm forms was not revealed.}, } @article {pmid36315083, year = {2022}, author = {Wagner, BM and Daigger, GT and Love, NG}, title = {Design methodologies to determine optimal staging of membrane-aerated biofilm reactors for mainstream treatment with anammox.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {8}, pages = {1887-1903}, doi = {10.2166/wst.2022.315}, pmid = {36315083}, issn = {0273-1223}, mesh = {*Ammonia ; *Bioreactors/microbiology ; Anaerobic Ammonia Oxidation ; Tin ; Biofilms ; Nitrogen ; Oxidation-Reduction ; Denitrification ; }, abstract = {Partial nitritation anammox (PNA) membrane-aerated biofilm reactors (MABRs) can be used in mainstream nitrogen removal to help facilities reduce their energy consumption. Previous PNA MABR research has not investigated the impacts of staging, i.e. arraying MABRs in series, on their nitrogen removal performance, operation, and ability to suppress nitrite oxidizing bacteria. In this paper, a mathematical model simulated PNA MABR performance at different influent total ammonia concentrations and loadings. A design methodology for staging PNA MABRs was created and found that the amount of membrane surface area is dependent upon the total ammonia-nitrogen concentration and loading, and the air loading to the membrane must be proportional to the total ammonia-nitrogen loading to maximize the total inorganic nitrogen (TIN) removal rate. This led to approximately equal-sized stages that each had a TIN removal percentage of 71% of the influent total ammonia nitrogen. Staging a treatment train resulted in 9.8% larger total ammonia and 9.3% larger total nitrogen removal rates when compared with an un-staged reactor. The un-staged reactor also was not able to produce an effluent total ammonia concentration below 5 mg N/L which would be necessary for many facilities' permits.}, } @article {pmid36312952, year = {2022}, author = {Dostert, M and Belanger, CR and Pedraz, L and Alford, MA and Blimkie, TM and Falsafi, RF and Bains, M and Dhillon, BK and Haney, CH and Lee, AH and Hancock, REW}, title = {BosR: A novel biofilm-specific regulator in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1021021}, pmid = {36312952}, issn = {1664-302X}, abstract = {Biofilms are the most common cause of bacterial infections in humans and notoriously hard to treat due to their ability to withstand antibiotics and host immune defenses. To overcome the current lack of effective antibiofilm therapies and guide future design, the identification of novel biofilm-specific gene targets is crucial. In this regard, transcriptional regulators have been proposed as promising targets for antimicrobial drug design. Therefore, a Transposon insertion sequencing approach was employed to systematically identify regulators phenotypically affecting biofilm growth in Pseudomonas aeruginosa PA14 using the TnSeq analysis tools Bio-TraDIS and TRANSIT. A screen of a pool of 300,000 transposon insertion mutants identified 349 genes involved in biofilm growth on hydroxyapatite, including 47 regulators. Detection of 19 regulatory genes participating in well-established biofilm pathways validated the results. An additional 28 novel prospective biofilm regulators suggested the requirement for multiple one-component transcriptional regulators. Biofilm-defective phenotypes were confirmed for five one-component transcriptional regulators and a protein kinase, which did not affect motility phenotypes. The one-component transcriptional regulator bosR displayed a conserved role in P. aeruginosa biofilm growth since its ortholog in P. aeruginosa strain PAO1 was also required for biofilm growth. Microscopic analysis of a chromosomal deletion mutant of bosR confirmed the role of this regulator in biofilm growth. Overall, our results highlighted that the gene network driving biofilm growth is complex and involves regulators beyond the primarily studied groups of two-component systems and cyclic diguanylate signaling proteins. Furthermore, biofilm-specific regulators, such as bosR, might constitute prospective new drug targets to overcome biofilm infections.}, } @article {pmid36311394, year = {2022}, author = {Rindi, L and He, J and Benedetti-Cecchi, L}, title = {Spatial correlation reverses the compound effect of multiple stressors on rocky shore biofilm.}, journal = {Ecology and evolution}, volume = {12}, number = {10}, pages = {e9418}, pmid = {36311394}, issn = {2045-7758}, abstract = {Understanding how multifactorial fluctuating environments affect species and communities remains one of the major challenges in ecology. The spatial configuration of the environment is known to generate complex patterns of correlation among multiple stressors. However, to what extent the spatial correlation between simultaneously fluctuating variables affects ecological assemblages in real-world conditions remains poorly understood. Here, we use field experiments and simulations to assess the influence of spatial correlation of two relevant climate variables - warming and sediment deposition following heavy precipitation - on the biomass and photosynthetic activity of rocky intertidal biofilm. First, we used a response-surface design experiment to establish the relation between biofilm, warming, and sediment deposition in the field. Second, we used the response surface to generate predictions of biofilm performance under different scenarios of warming and sediment correlation. Finally, we tested the predicted outcomes by manipulating the degree of correlation between the two climate variables in a second field experiment. Simulations stemming from the experimentally derived response surface showed how the degree and direction (positive or negative) of spatial correlation between warming and sediment deposition ultimately determined the nonlinear response of biofilm biomass (but not photosynthetic activity) to fluctuating levels of the two climate variables. Experimental results corroborated these predictions, probing the buffering effect of negative spatial correlation against extreme levels of warming and sediment deposition. Together, these results indicate that consideration of nonlinear response functions and local-scale patterns of correlation between climate drivers can improve our understanding and ability to predict ecological responses to multiple processes in heterogeneous environments.}, } @article {pmid36311355, year = {2022}, author = {Samreen, and Qais, FA and Ahmad, I}, title = {Anti-quorum sensing and biofilm inhibitory effect of some medicinal plants against gram-negative bacterial pathogens: in vitro and in silico investigations.}, journal = {Heliyon}, volume = {8}, number = {10}, pages = {e11113}, pmid = {36311355}, issn = {2405-8440}, abstract = {Multidrug resistance (MDR) in pathogenic bacteria have become a major clinical issue. Quorum sensing regulated bacterial virulence is a promising key drug target for MDR infections. Therefore, the aim of the present work was to assess the anti-quorum sensing properties of selected medicinal plants against bacterial pathogens as well in silico interaction of selected bioactive phytocompounds with QS and biofilm-associated proteins. Based on the ethnopharmacological usage, 18 plants were selected using methanolic extract against Chromobacterium violaceum 12472. The most active extract (Acacia nilotica) was fractionated in increasing polarity solvents (n-hexane, chloroform and ethyl acetate) and tested for anti-QS activity. The most active fraction i.e. ethyl acetate fraction was evaluated for their activity at sub-MICs against QS-associated virulence factors of Pseudomonas aeruginosa PAO1 and Serretia marcescens MTCC 97. Microtiter plate assay and light microscopy was used to determine inhibition of biofilm. Phytochemicals of the ethyl acetate fraction were analysed by GC/MS and LC/MS. Phytocompounds were docked with QS (LasI, LasR, CviR, and rhlR) and biofilm proteins (PilY1 and PilT) using Auto dock vina. The MIC of ethyl acetate fraction determined was 250, 500, and 1000 μg/ml against C. violaceum 12472, P. aeruginosa PAO1, and S. marcescens MTCC97 respectively. At sub-MICs QS regulated virulence factors production and inhibited biofilms broadly (more than 50 percent). GC/MS detected the major bioactive compound benzoic acid, 3,4,5-trihydroxy-, methyl ester (61.24 %) and LC-MS detected Retronecine for the first time in A. nilotica pods. In silico, dehydroabietic acid occupied the same cavity as its antagonist in the CviR ligand binding domain. Also, betulin and epicatechin gallate interact with biofilm proteins PilY1 and PilT, preventing biofilm formation. The findings suggest that the phytochemicals of A. nilotica pod could be exploited as an anti-QS agent against Gram-negative pathogens. To discover therapeutic efficacy of standardised bioactive extract/phytochemicals must be tested under in vivo condition.}, } @article {pmid36310876, year = {2022}, author = {Deng, W and Lei, Y and Tang, X and Li, D and Liang, J and Luo, J and Liu, L and Zhang, W and Ye, L and Kong, J and Wang, K and Chen, Z}, title = {DNase inhibits early biofilm formation in Pseudomonas aeruginosa- or Staphylococcus aureus-induced empyema models.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {917038}, pmid = {36310876}, issn = {2235-2988}, mesh = {Animals ; Rabbits ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Deoxyribonucleases/pharmacology ; In Situ Hybridization, Fluorescence ; *Staphylococcal Infections/drug therapy ; Biofilms ; Anti-Bacterial Agents/therapeutic use ; Deoxyribonuclease I/pharmacology ; *Empyema, Pleural ; }, abstract = {Anti-infection strategies against pleural empyema include the use of antibiotics and drainage treatments, but bacterial eradication rates remain low. A major challenge is the formation of biofilms in the pleural cavity. DNase has antibiofilm efficacy in vitro, and intrapleural therapy with DNase is recommended to treat pleural empyema, but the relevant mechanisms remain limited. Our aim was to investigate whether DNase I inhibit the early biofilm formation in Pseudomonas aeruginosa- or Staphylococcus aureus-induced empyema models. We used various assays, such as crystal violet staining, confocal laser scanning microscopy (CLSM) analysis, peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH), and scanning electron microscopy (SEM) analysis. Our results suggested that DNase I significantly inhibited early biofilm formation in a dose-dependent manner, without affecting the growth of P. aeruginosa or S. aureus in vitro. CLSM analysis confirmed that DNase I decreased the biomass and thickness of both bacterial biofilms. The PNA-FISH and SEM analyses also revealed that DNase I inhibited early (24h) biofilm formation in two empyema models. Thus, the results indicated that DNase inhibited early (24h) biofilm formation in P. aeruginosa- or S. aureus-induced rabbit empyema models and showed its therapeutic potential against empyema biofilms.}, } @article {pmid36309453, year = {2023}, author = {Agustín, MDR and Tarifa, MC and Vela-Gurovic, MS and Brugnoni, LI}, title = {Application of natamycin and farnesol as bioprotection agents to inhibit biofilm formation of yeasts and foodborne bacterial pathogens in apple juice processing lines.}, journal = {Food microbiology}, volume = {109}, number = {}, pages = {104123}, doi = {10.1016/j.fm.2022.104123}, pmid = {36309453}, issn = {1095-9998}, mesh = {Farnesol/pharmacology ; *Malus/microbiology ; Natamycin/pharmacology ; Food Microbiology ; *Escherichia coli O157 ; Stainless Steel ; Yeasts ; Biofilms ; *Listeria monocytogenes ; Colony Count, Microbial ; }, abstract = {Biofilms serve as a reservoir for pathogenic and spoilage microorganisms, and their removal from different surfaces is a recurring problem in the beverage industry. This study aimed to investigate the effect of a combination of natamycin (NAT, 0.01 mmol/l) and farnesol (FAR, 0.6 mmol/l) against biofilms on ultrafiltration (UF) membranes and stainless steel (SS) surfaces using apple juice as food matrix. The co-adhesion of Rhodotorula mucilaginosa, Candida tropicalis, C. krusei and C. kefyr (mixed-yeast) with Listeria monocytogenes, Salmonella enterica or Escherichia coli O157:H7 (multi-species) in presence of NAT + FAR was evaluated for 2, 24, 48 h. In biofilms treated with NAT + FAR were observed by cell quantification and microscopy, inhibition of the filamentous yeast forms, disruption of the tri-dimensional structure and a high detachment of yeast cells. NAT + FAR affected the biofilms independently of the surfaces used and the presence (or not) of bacteria. L. monocytogenes was the most susceptible (p < 0.001) in multi-species biofilms, followed by E. coli O157:H7 on both surfaces (p < 0.001), whereas the growth of S. enterica was reduced (p < 0.05) in SS but not in UF-membranes (p > 0.05). Since the combination NAT + FAR affected the structure and viability of yeast species and foodborne pathogens in multi-species biofilms developed on UF-membranes and SS surfaces, the combination proposed could be considered a promising control agent to prevent biofilms in apple juice processing lines.}, } @article {pmid36309448, year = {2023}, author = {Chen, J and Sun, Z and Jin, J and Wang, F and Yang, Q and Yu, H and Yu, J and Wang, Y}, title = {Role of siderophore in Pseudomonas fluorescens biofilm formation and spoilage potential function.}, journal = {Food microbiology}, volume = {109}, number = {}, pages = {104151}, doi = {10.1016/j.fm.2022.104151}, pmid = {36309448}, issn = {1095-9998}, mesh = {Animals ; *Siderophores ; *Pseudomonas fluorescens/genetics ; Biofilms ; }, abstract = {We investigated the function of pyoverdine in the biofilm formation, motility, and spoilage potential of Pseudomonas fluorescens. We targeted and identified two major genes (pvdA and pvdE) that are involved in the biosynthesis of siderophores. We next constructed ΔpvdA and ΔpvdE mutants of P. fluorescens PF08 and found that the deletion of pyoverdine led to a biofilm-to-motivity transition as both ΔpvdA and ΔpvdE mutants displayed enhanced motility, reduced level of exopolysaccharides (EPSs), and attenuated biofilm formation. In addition, the lack of synthesis of pyoverdine promoted the spoilage of fish fillets stored at 4 °C. Based on the effect of pyoverdine deletion on the phenotype; we report that pyoverdine regulates the transcription levels of htpX, phoA, flip, flgA, and RpoS, suggesting that pyoverdine-mediated iron absorption may affect the regulation of flagellum and stress resistance. This study emphasizes the important role of pyoverdine in the formation of biofilm, motility, and spoilage of P. fluorescens PF08.}, } @article {pmid36308961, year = {2023}, author = {Ye, Y and Ma, S and Peng, H and Huang, Y and Zeng, W and Xia, A and Zhu, X and Liao, Q}, title = {Insight into the comprehensive effect of carbon dioxide, light intensity and glucose on heterotrophic-assisted phototrophic microalgae biofilm growth: A multifactorial kinetic model.}, journal = {Journal of environmental management}, volume = {325}, number = {Pt B}, pages = {116582}, doi = {10.1016/j.jenvman.2022.116582}, pmid = {36308961}, issn = {1095-8630}, mesh = {*Microalgae ; Carbon Dioxide/pharmacology ; Glucose/pharmacology ; Kinetics ; Biofilms ; Biomass ; }, abstract = {Heterotrophic-assisted photoautotrophic microalgae biofilm cultivation was an alternative way to realize CO2 reduction and wastewater treatment. Growth kinetics supplied a channel to better understand how the cultivation conditions affect microalgal growth and CO2 reduction. However, the two growth modes (heterotroph and photoautotroph) have different needs for organic and inorganic nutrients. Thus, combining the threshold theory and multiplication theory, an integral multifactorial kinetic model that looking insight into the comprehensive effect of glucose, CO2, light intensity, and nitrate was developed for heterotrophic-assisted photoautotrophic microalgae biofilm growth in this study. R[2] between model and experiment was 0.99. It predicted the maximum specific growth rate and maximum CO2 consumption rate of heterotrophic-assisted photoautotrophic microalgae biofilm was 1.868 h[-1] and 1.02 h[-1], respectively. This model fully explained the influence of the main factors on microalgae biofilm growth and reasonably predicted the growth rate of microalgae biofilm under different growth conditions.}, } @article {pmid36308955, year = {2023}, author = {Zhang, H and Zhang, SS and Zhang, W and Zhu, L and Li, YP and Pan, Y}, title = {Biomineralization and AHLs-guided quorum sensing enhanced phosphorus recovery in the alternating aerobic/anaerobic biofilm system under metal ion stress.}, journal = {Journal of environmental management}, volume = {325}, number = {Pt B}, pages = {116583}, doi = {10.1016/j.jenvman.2022.116583}, pmid = {36308955}, issn = {1095-8630}, mesh = {*Acyl-Butyrolactones/metabolism ; *Quorum Sensing ; Phosphorus ; Anaerobiosis ; Biomineralization ; Biofilms ; Polyphosphates ; Metals ; }, abstract = {The alternating aerobic/anaerobic biofilm system had been applied for phosphorus (P) enrichment and recovery because of the advantage of low energy consumption and high efficiency. The metal ions and N-acyl-L-homoserine lactones (AHLs) in system were studied to better clarify the mechanism of P uptake/release under metal ion stress. The results indicated that the increase of metal ions stimulated the release of AHLs, and AHLs-guided quorum sensing (QS) enhanced P uptake. Moreover, biomineralization could stimulate the increase of P content in biofilm (Pbiofilm). Meanwhile, some ortho-p was converted to short-chain poly-p in extracellular polymer substance (EPS), and others were transferred into cell through EPS to synthesize poly-p. With the Pbiofilm increased, more P could be absorbed/released due to the shift in the metabolic model of polyphosphate accumulating organisms (PAOs). The release of AHLs between microorganisms was also inhibited when PAOs reached the state of P saturation (75.6 ± 2.5 mg/g SS), which meant that the effect of signaling function would tend to stabilize, and the 169.2 ± 2.6 mg/L P concentration in the enriched solution was obtained due to the P release was inhibited. Moreover, P was rapidly transferred to the new enriched solution after the P was recovered, and PAOs restored its capability of P uptake/release. In addition, [31]P-NMR analysis demonstrated that EPS played a major role in PAOs compared to cell, and inorganic phosphorus (IP) played an essential role in the uptake/release of P compared to organic phosphorus (OP). Furthermore, the microbiological analysis showed that Candidatus Accumulibacter was positively correlated with AHLs (P < 0.05). This study provided essential support for clarifying the P metabolism mechanism of PAOs.}, } @article {pmid36308833, year = {2023}, author = {Zhang, Y and Huang, Y and Ding, H and Ma, J and Tong, X and Zhang, Y and Tao, Z and Wang, Q}, title = {A σ[E]-mediated temperature gauge orchestrates type VI secretion system, biofilm formation and cell invasion in pathogen Pseudomonas plecoglossicida.}, journal = {Microbiological research}, volume = {266}, number = {}, pages = {127220}, doi = {10.1016/j.micres.2022.127220}, pmid = {36308833}, issn = {1618-0623}, mesh = {Animals ; *Type VI Secretion Systems ; Temperature ; *Pseudomonas Infections/microbiology ; *Perciformes/metabolism/microbiology ; Sigma Factor/genetics ; Biofilms ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Pseudomonas plecoglossicida is a temperature-dependent opportunistic pathogen mediating visceral granulomas in many piscine species including the large yellow croaker (Larimichthys crocea) but the underlying mechanisms are unclear. RpoE is an alternative sigma (σ) factor involved in regulated intramembrane proteolytic (RIP) cascade, enabling bacterial pathogens to coordinate the expression of genetic traits associated with stress adaptation and virulence determinants in response to diverse stimuli in vitro and in vivo of the hosts. In this study, genes associated to RIP cascade in P. plecoglossicida were identified and characterized to show various sequence similarities to their counterparts in Escherichia coli and P. aeruginosa. The expression of P. plecoglossicida RIP locus was induced by higher temperatures. Moreover, RNA sequencing approach revealed that RpoE regulated the expression of ∼297 and ∼261 genes at virulent (18 °C) and non-virulent (28 °C) temperatures, respectively. RpoE regulon genes are involved in various processes associated with bacterial signal transduction, membrane homeostasis, energy metabolism and virulence. In particular, RpoE positively controlled expression of csrA encoding an RNA binding protein essential for central carbon metabolism. In addition, P. plecoglossicida RpoE was validated to regulate type VI secretion system (T6SS) expression, bacteria competition, biofilm formation and reproduction in macrophages. Collectively, RpoE-centered RIP cascade appeared to play important roles in control of the expression of genes involved in adaptation in vivo and in vitro niches by thermal sensing in P. plecoglossicida. These results facilitates to reveal the pathogenic mechanisms of P. plecoglossicida causing fish diseases and provides new perspectives to control bacterial infection.}, } @article {pmid36308494, year = {2022}, author = {Farjami, A and Jalilzadeh, S and Siahi-Shadbad, M and Lotfipour, F}, title = {The anti-biofilm activity of hydrogen peroxide against Escherichia coli strain FL-Tbz isolated from a pharmaceutical water system.}, journal = {Journal of water and health}, volume = {20}, number = {10}, pages = {1497-1505}, doi = {10.2166/wh.2022.061}, pmid = {36308494}, issn = {1477-8920}, mesh = {Humans ; *Escherichia coli ; Hydrogen Peroxide/pharmacology ; Water ; Biofilms ; *Escherichia coli Infections ; Pharmaceutical Preparations ; }, abstract = {Biofilms are considered a significant reason for the failure of disinfection strategies in industrial water systems due to their resistance to antimicrobial agents. This study is designed to investigate the anti-biofilm activity of hydrogen peroxide (H2O2) at combinations of temperatures and contact times. For this purpose, an in vitro microtiter plate (MTP)-based model system was used for biofilm formation using Escherichia coli (E. coli) strain FL-Tbz isolated from the water system of a pharmaceutical plant. To investigate the anti-biofilm activity of H2O2, it was added at different concentrations (2-7% v/v) to biofilms and incubated at different temperatures (20-60 °C) for 10-40 min to find effective conditions to eradicate biofilms. Maximum biofilms were formed when bacterial suspensions were incubated at 37 °C for 96 h. The rate of biofilm formation using an environmental isolate was higher than that of standard strain. H2O2 at concentrations of ≥6.25% (v/v) at temperatures of ≥40 °C incubated for ≥25 min significantly eradicated the biofilms.}, } @article {pmid36306650, year = {2023}, author = {Yao, X and Sun, J and Bai, X and Yuan, Y and Zhang, Y and Xu, Y and Huang, G}, title = {A high-efficiency mixotrophic photoelectroactive biofilm reactor (MPBR) for enhanced simultaneous removal of nutrients and antibiotics by integrating light intensity regulation and microbial extracellular electron extraction.}, journal = {Journal of environmental management}, volume = {325}, number = {Pt A}, pages = {116520}, doi = {10.1016/j.jenvman.2022.116520}, pmid = {36306650}, issn = {1095-8630}, mesh = {*Electrons ; *Anti-Bacterial Agents ; Biofilms ; Biomass ; Nutrients ; Sulfadiazine ; Wastewater ; Bioreactors ; }, abstract = {The performance of a mixotrophic photoelectroactive biofilm reactor (MPBR) was improved in order to achieve enhanced simultaneous removal of multiple aqueous pollutants and the production of valuable biomass. The MPBR was optimized by integrating the regulation of light intensity (3000, 8000 and 23000 lux) and microbial extracellular electron extraction (using an electrode at -0.3, 0 and 0.3 V). Results showed that the MPBR operated at a high light intensity (23000 lux) with a potential of -0.3 V (Coulomb efficiency (CE) of 9.65%) achieved maximum pollutant removal efficiencies, effectively removing 65% NH4[+]-N, 95% PO4[3-]-P and 52% sulfadiazine (SDZ) within 72 h, exhibiting an increase by 30%, 56% and 26% compared to an MPBR operated at the same light intensity but without an externally applied potential. The use of an electrode with an applied potential of -0.3V was most suitable for the extraction of photosynthetic electrons from the photoelectroactive biofilm, in which Rhodocyclaceae was highly enriched, effectively alleviating photoinhibition and thereby enhancing N, P assimilation and SDZ degradation under high light conditions. A maximum lipid content of 409.28 mg/g was obtained under low light intensity (3000 lux) conditions with an applied potential of 0.3 V (CE 9.08%), while a maximum protein content of 362.29 mg/g was obtained at a low light intensity (3000 lux) and 0 V (CE 10.71%). The selective enrichment of Chlorobium and the subsequent enhanced conversion of excess available carbon under low light and positive potential stimulation conditions, were responsible for the enhanced accumulation of proteins and lipids in biomass.}, } @article {pmid36306585, year = {2022}, author = {Cesaria, M and Alfinito, E and Arima, V and Bianco, M and Cataldo, R}, title = {MEED: A novel robust contrast enhancement procedure yielding highly-convergent thresholding of biofilm images.}, journal = {Computers in biology and medicine}, volume = {151}, number = {Pt A}, pages = {106217}, doi = {10.1016/j.compbiomed.2022.106217}, pmid = {36306585}, issn = {1879-0534}, mesh = {*Image Processing, Computer-Assisted/methods ; *Algorithms ; Artifacts ; Databases, Factual ; Biofilms ; Image Enhancement/methods ; }, abstract = {Morphological and statistical investigation of biofilm images may be even more critical than the image acquisition itself, in particular in the presence of morphologically complex distributions, due to the unavoidable impact of the measurement technique too. Hence, digital image pre-processing is mandatory for reliable feature extraction and enhancement preliminary to segmentation. Also, pattern recognition in automated deep learning (both supervised and unsupervised) models often requires a preliminary effective contrast-enhancement. However, no universal consensus exists on the optimal contrast enhancement approach. This paper presents and discusses a new general, robust, reproducible, accurate and easy to implement contrast enhancement procedure, briefly named MEED-procedure, able to work on images with different bacterial coverages and biofilm structures, coming from different imaging instrumentations (herein stereomicroscope and transmission microscope). It exploits a proper succession of basic morphological operations (erosion and dilation) and a horizontal line structuring element, to minimize the impact on size and shape of the even finer bacterial features. It systematically enhances the objects of interest, without histogram stretching and/or undesirable artifacts yielded by common automated methods. The quality of the MEED-procedure is ascertained by segmentation tests which demonstrate its robustness regarding the determination of threshold and convergence of the thresholding algorithm. Extensive validation tests over a rich image database, comparison with the literature and comprehensive discussion of the conceptual background support the superiority of the MEED-procedure over the existing methods and demonstrate it is not a routine application of morphological operators.}, } @article {pmid36305479, year = {2023}, author = {Li, M and Nahum, Y and Matouš, K and Stoodley, P and Nerenberg, R}, title = {Effects of biofilm heterogeneity on the apparent mechanical properties obtained by shear rheometry.}, journal = {Biotechnology and bioengineering}, volume = {120}, number = {2}, pages = {553-561}, doi = {10.1002/bit.28276}, pmid = {36305479}, issn = {1097-0290}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; 1805406//National Science Foundation/ ; }, mesh = {*Biofilms ; Computer Simulation ; Viscosity ; Elasticity ; }, abstract = {Rheometry is an experimental technique widely used to determine the mechanical properties of biofilms. However, it characterizes the bulk mechanical behavior of the whole biofilm. The effects of biofilm mechanical heterogeneity on rheometry measurements are not known. We used laboratory experiments and computer modeling to explore the effects of biofilm mechanical heterogeneity on the results obtained by rheometry. A synthetic biofilm with layered mechanical properties was studied, and a viscoelastic biofilm theory was employed using the Kelvin-Voigt model. Agar gels with different concentrations were used to prepare the layered, heterogeneous biofilm, which was characterized for mechanical properties in shear mode with a rheometer. Both experiments and simulations indicated that the biofilm properties from rheometry were strongly biased by the weakest portion of the biofilm. The simulation results using linearly stratified mechanical properties from a previous study also showed that the weaker portions of the biofilm dominated the mechanical properties in creep tests. We note that the model can be used as a predictive tool to explore the mechanical behavior of complex biofilm structures beyond those accessible to experiments. Since most biofilms display some degree of mechanical heterogeneity, our results suggest caution should be used in the interpretation of rheometry data. It does not necessarily provide the "average" mechanical properties of the entire biofilm if the mechanical properties are stratified.}, } @article {pmid36304952, year = {2022}, author = {Ahmed, B and Jailani, A and Lee, JH and Lee, J}, title = {Inhibition of growth, biofilm formation, virulence, and surface attachment of Agrobacterium tumefaciens by cinnamaldehyde derivatives.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1001865}, pmid = {36304952}, issn = {1664-302X}, abstract = {Agrobacterium tumefaciens, a soil-borne, saprophytic plant pathogen that colonizes plant surfaces and induces tumors in a wide range of dicotyledonous plants by transferring and expressing its T-DNA genes. The limited availabilities and efficacies of current treatments necessitate the exploration of new anti-Agrobacterium agents. We examined the effects of trans-cinnamaldehyde (t-CNMA) and its derivatives on the cell surface hydrophobicity, exopolysaccharide and exo-protease production, swimming motility on agar, and biofilm forming ability of A. tumefaciens. Based on initial biofilm inhibition results and minimum inhibitory concentration (MIC) data, 4-nitro, 4-chloro, and 4-fluoro CNMAs were further tested. 4-Nitro, 4-chloro, and 4-fluoro CNMA at ≥150 μg/ml significantly inhibited biofilm formation by 94-99%. Similarly, biofilm formation on polystyrene or nylon was substantially reduced by 4-nitro and 4-chloro CNMAs as determined by optical microscopy and scanning electron microscopy (SEM) and 3-D spectrum plots. 4-Nitro and 4-chloro CNMAs induced cell shortening and concentration- and time-dependently reduced cell growth. Virulence factors were significantly and dose-dependently suppressed by 4-nitro and 4-chloro CNMAs (P ≤ 0.05). Gene expressional changes were greater after 4-nitro CNMA than t-CNMA treatment, as determined by qRT-PCR. Furthermore, some genes essential for biofilm formation, motility, and virulence genes significantly downregulated by 4-nitro CNMA. Seed germination of Raphanus sativus was not hindered by 4-nitro or 4-fluoro CNMA at concentrations ≤200 μg/ml, but root surface biofilm formation was severely inhibited. This study is the first to report the anti-Agrobacterium biofilm and anti-virulence effects of 4-nitro, 4-chloro, and 4-fluoro CNMAs and t-CNMA and indicates that they should be considered starting points for the development of anti-Agrobacterium agents.}, } @article {pmid36304951, year = {2022}, author = {Wu, S and Qin, B and Deng, S and Liu, Y and Zhang, H and Lei, L and Feng, G}, title = {CodY is modulated by YycF and affects biofilm formation in Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {967567}, pmid = {36304951}, issn = {1664-302X}, abstract = {BACKGROUND: Staphylococcus aureus (S. aureus) is the leading cause of various infective diseases, including topical soft tissue infections. The goals of this study were to investigate the roles of YycF and CodY in the regulation of biofilm formation and pathogenicity.

METHODS: Electrophoretic mobility shift assay (EMSA) was conducted to validate the bound promoter regions of YycF protein. We constructed the codY up-regulated or down-regulated S. aureus mutants. The biofilm biomass was determined by crystal violet microtiter assay and scanning electron microscopy (SEM). Quantitative RT-PCR analysis was used to detect the transcripts of biofilm-related genes. The live and dead cells of S. aureus biofilm were also investigated by confocal laser scanning microscopy (CLSM). We constructed an abscess infection in Sprague Dawley (SD) rat models to determine the effect of CodY on bacterial pathogenicity. We further used the RAW264.7, which were cocultured with S. aureus, to evaluate the effect of CodY on macrophages apoptosis.

RESULT: Quantitative RT-PCR analyses reveled that YycF negatively regulates codY expression. EMSA assays indicated that YycF protein directly binds to the promoter regions of codY gene. Quantitative RT-PCR confirmed the construction of dual- mutant stains codY + ASyycF and codY-ASyycF. The SEM results showed that the biofilm formation in the codY + ASyycF group was sparser than those in the other groups. The crystal violet assays indicated that the codY + ASyycF group formed less biofilms, which was consistent with the immunofluorescence results of the lowest live cell ration in the codY + ASyycF group. The expression levels of biofilm-associated icaA gene were significantly reduced in the codY + strain, indicating codY negatively regulates the biofilm formation. Furthermore, CodY impedes the pathogenicity in a rat-infection model. After cocultured with bacteria or 4-h in vitro, the apoptosis rates of macrophage cells were lowest in the codY + group.

CONCLUSIONS: YycF negatively regulate the expression of codY. By interaction with codY, YycF could modulate S. aureus biofilm formation via both eDNA- dependent and PIA- dependent pathways, which can be a significant target for antibiofilm. CodY not only impedes the pathogenicity but also has a role on immunoregulation. Thus, the current evidence may provide a supplementary strategy for managing biofilm infections.}, } @article {pmid36303921, year = {2022}, author = {Caixeta Magalhães Tibúrcio, AA and Paiva, AD and Pedrosa, AL and Rodrigues, WF and Bernardes da Silva, R and Oliveira, AG}, title = {Effect of sub-inhibitory concentrations of antibiotics on biofilm formation and expression of virulence genes in penicillin-resistant, ampicillin-susceptible Enterococcus faecalis.}, journal = {Heliyon}, volume = {8}, number = {10}, pages = {e11154}, pmid = {36303921}, issn = {2405-8440}, abstract = {Biofilm formation is a key factor in the pathogenesis of enterococcal infections. Thus, the biofilm-forming ability and frequency of biofilm-related genes in penicillin-resistant, ampicillin-susceptible Enterococcus faecalis (PRASEF) compared to penicillin- and ampicillin-susceptible E. faecalis (PSASEF) were assessed in the present study. In addition, the effect of sub-inhibitory concentrations (sub-MICs) of antibiotics on biofilm formation and expression of virulence genes was evaluated. Twenty PRASEF and 21 PSASEF clinical isolates were used to determine the effect of sub-MICs of antibiotics (ampicillin, penicillin, and gentamicin) on biofilm formation, and ten selected isolates were subjected to RT-qPCR to detect the transcript levels of virulence genes (efaA, asa1, esp, and ace). Antibiotic susceptibility was evaluated by the microdilution broth method. Biofilm formation assay was performed using the microtiter plate method. All PSASEF and PRASEF isolates produced biofilms in vitro. Most isolates had three or four virulence genes. Sub-MICs of ampicillin significantly decreased biofilm production and expression of ace and asa1 genes, although the transcript levels were significantly lower (-350% and -606.2%, respectively) among the PSASEF isolates only. Sub-MICs of gentamicin did not have any significant effect on biofilm formation, but slightly increased the transcript levels of efaA. In conclusion, this study showed that the biofilm-forming ability and frequency of the evaluated virulence genes were similar among the PRASEF and PSASEF isolates. Further, in vitro antibiotic sub-MICs were confirmed to interfere with the expression pattern of virulence genes and biofilm formation by E. faecalis. However, further studies are required to clarify the role of sublethal doses of antibiotics on enterococcal biofilms.}, } @article {pmid36303845, year = {2022}, author = {Halsted, MC and Bible, AN and Morrell-Falvey, JL and Retterer, ST}, title = {Quantifying biofilm propagation on chemically modified surfaces.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100088}, pmid = {36303845}, issn = {2590-2075}, abstract = {Conditions affecting biofilm formation differ among bacterial species and this presents a challenge to studying biofilms in the lab. This work leverages functionalized silanes to control surface chemistry in the study of early biofilm propagation, quantified with a semi-automated image processing algorithm. These methods support the study of Pantoea sp. YR343, a gram-negative bacterium isolated from the poplar rhizosphere. We found that Pantoea sp. YR343 does not readily attach to hydrophilic surfaces but will form biofilms with a "honeycomb" morphology on hydrophobic surfaces. Our image processing algorithm described here quantified the evolution of the honeycomb morphology over time, and found the propagation to display a logarithmic behavior. This methodology was repeated with a flagella-deficient fliR mutant of Pantoea sp. YR343 which resulted in reduced surface attachment. Quantifiable differences between Pantoea WT and ΔfliR biofilm morphologies were captured by the image processing algorithm, further demonstrating the insight gained from these methods.}, } @article {pmid36303343, year = {2023}, author = {He, S and Tong, J and Xiong, W and Xiang, Y and Peng, H and Wang, W and Yang, Y and Ye, Y and Hu, M and Yang, Z and Zeng, G}, title = {Microplastics influence the fate of antibiotics in freshwater environments: Biofilm formation and its effect on adsorption behavior.}, journal = {Journal of hazardous materials}, volume = {442}, number = {}, pages = {130078}, doi = {10.1016/j.jhazmat.2022.130078}, pmid = {36303343}, issn = {1873-3336}, mesh = {*Microplastics ; Plastics/chemistry ; Adsorption ; Anti-Bacterial Agents ; Polyethylene/chemistry ; Polyvinyl Chloride ; *Water Pollutants, Chemical/analysis ; Biofilms ; Water ; Fresh Water ; }, abstract = {Microplastics (MPs) are substrates available for biofilms colonization in natural water environments. The biofilms formation may enhance the ability of MPs to adsorb harmful contaminants. Herein, we investigated the biofilms formation of three different MPs (PVC, PA and HDPE) in simulated natural environment, and observed the chemical structure, charge property, hydrophobicity and other properties of MPs affect microbial biomass and community composition. More importantly, potential pathogens were found in all three MPs biofilms. Furthermore, the adsorption capacities of original MPs and biological aging MPs for norfloxacin (NOR) was compared. HDPE has the largest adsorption capacity for NOR, while PA has the smallest adsorption capacity for NOR. It was concluded that the formation of biofilms enhanced the adsorption of NOR by 50.60 %, 24.17 % and 46.02 % for PVC, PA and HDPE, respectively. In addition, hydrogen-bond interaction, electrostatic interaction and hydrophobic interaction were found to dominate the adsorption of NOR by MPs. Our study contributed to improve the understanding of the interactions between aging MPs and contaminants in the natural water environments, and provided essential information for ecological risk assessment of MPs.}, } @article {pmid36301743, year = {2022}, author = {Łysik, D and Deptuła, P and Chmielewska, S and Skłodowski, K and Pogoda, K and Chin, L and Song, D and Mystkowska, J and Janmey, PA and Bucki, R}, title = {Modulation of Biofilm Mechanics by DNA Structure and Cell Type.}, journal = {ACS biomaterials science & engineering}, volume = {8}, number = {11}, pages = {4921-4929}, pmid = {36301743}, issn = {2373-9878}, mesh = {*Biofilms ; *Pseudomonas aeruginosa ; Staphylococcus aureus/metabolism ; DNA/metabolism/pharmacology ; }, abstract = {Deoxyribonucleic acid (DNA) evolved as a tool for storing and transmitting genetic information within cells, but outside the cell, DNA can also serve as "construction material" present in microbial biofilms or various body fluids, such as cystic fibrosis, sputum, and pus. In the present work, we investigate the mechanics of biofilms formed from Pseudomonas aeruginosa Xen 5, Staphylococcus aureus Xen 30, and Candida albicans 1408 using oscillatory shear rheometry at different levels of compression and recreate these mechanics in systems of entangled DNA and cells. The results show that the compression-stiffening and shear-softening effects observed in biofilms can be reproduced in DNA networks with the addition of an appropriate number of microbial cells. Additionally, we observe that these effects are cell-type dependent. We also identify other mechanisms that may significantly impact the viscoelastic behavior of biofilms, such as the compression-stiffening effect of DNA cross-linking by bivalent cations (Mg[2+], Ca[2+], and Cu[2+]) and the stiffness-increasing interactions of P. aeruginosa Xen 5 biofilm with Pf1 bacteriophage produced by P. aeruginosa. This work extends the knowledge of biofilm mechanobiology and demonstrates the possibility of modifying biopolymers toward obtaining the desired biophysical properties.}, } @article {pmid36300948, year = {2022}, author = {Wang, S and Zhu, H and Zheng, G and Dong, F and Liu, C}, title = {Dynamic Changes in Biofilm Structures under Dynamic Flow Conditions.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {22}, pages = {e0107222}, pmid = {36300948}, issn = {1098-5336}, mesh = {*Biofilms ; *Hydrodynamics ; Stress, Mechanical ; Computer Simulation ; Porosity ; }, abstract = {Quantitative assessment of the responses of biofilm structure to external hydrodynamics is critical for understanding biofilm detachment mechanisms. This study used multidimensional imaging and numerical simulation approaches to elucidate the complex relationships between biofilm detachment and hydrodynamics with Shewanella oneidensis MR-1. By integrating real-time confocal laser scanning microscopy (CLSM) images with image analysis tools, the three-dimensional structural changes occurring in thin MR-1 biofilms (<10 μm) under hydrodynamic treatment at a flow velocity of 0.42 × 10[-3] to 3.3 × 10[-3] m/s in the laminar flow regime were visualized in situ and quantified with single-cell resolution. Analyses of the imaging results revealed high spatial heterogeneity in the degree and intensity of biofilm detachment. Spots with thick and rough biofilm surfaces or high flow rates had high detachment rates, indicating that local biofilm morphology, including thickness and roughness, and hydrodynamic flow conditions collectively controlled the detachment rate. Numerical simulations revealed a significant correlation between local detachment events and the shear stress induced by hydraulic flow at the three-dimensional level. Compared to the even or thin biofilm, a thick or rough structure might induce a 2-fold increase in shear stress over local biofilm surfaces at a microscale dimension. The results provide quantitative and microscopic insights into biofilm detachment processes in subsurface environments, especially in domains under dynamic flow conditions, such as those in hyporheic zones. The relationship between biofilm detachment and hydrodynamics and biofilm structural factors can be integrated into reactive transport models used to describe microbial growth and transport in porous media. IMPORTANCE Detachment is an important process determining the structure and function of bacterial biofilm, which has significant implications for biogeochemical cycling of elements, biofilm application, and infection control in clinical settings. Quantifying the responses of biofilm structure to hydrodynamics is crucial for understanding biofilm detachment mechanisms in aquatic environments. In this work, the spatial and temporal changes occurring in biofilm structures in response to different hydrodynamic conditions were studied by using flow cell reactors. We established the quantitative relationships among detachment, biofilm morphology, and shear stress induced by changes in hydrodynamic conditions. This work provides a quantitative understanding of the complex relationship between biofilm detachment and hydrodynamics in natural environments.}, } @article {pmid36300593, year = {2022}, author = {Koley, D}, title = {Electrochemical sensors for oral biofilm-biomaterials interface characterization: A review.}, journal = {Molecular oral microbiology}, volume = {37}, number = {6}, pages = {292-298}, pmid = {36300593}, issn = {2041-1014}, support = {R01 DE027999/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; Biocompatible Materials ; Biofilms ; *Dental Caries/microbiology ; *Tooth ; Bacteria ; }, abstract = {Important processes related to the interaction of the oral microbiome with the tooth surface happen directly at the interface. For example, the chemical microenvironment that exists at the interface of microbial biofilms and the native tooth structure is directly involved in caries development. Consequentially, a critical understanding of this interface and its chemical microenvironment would provide novel avenues in caries prevention, including secondary caries that often occurs at the interface of the dental biofilm, tooth structure, and dental material. Electrochemical sensors are a unique quantitative tool and have the inherent advantages of miniaturization, stability, and selectivity. That makes the electrochemical sensors ideal tools for studying these critical biofilm microenvironments with high precision. This review highlights the development and applications of several novel electrochemical sensors such as pH, Ca[2+] , and hydrogen peroxide sensors as scanning electrochemical microscope probes in addition to flexible pH wire sensors for real-time bacterial biofilm-dental surface and dental materials interface studies.}, } @article {pmid36299721, year = {2022}, author = {Zhang, H and Yan, Q and An, Z and Wen, Z}, title = {A revolving algae biofilm based photosynthetic microbial fuel cell for simultaneous energy recovery, pollutants removal, and algae production.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {990807}, pmid = {36299721}, issn = {1664-302X}, abstract = {Photosynthetic microbial fuel cell (PMFC) based on algal cathode can integrate of wastewater treatment with microalgal biomass production. However, both the traditional suspended algae and the immobilized algae cathode systems have the problems of high cost caused by Pt catalyst and ion-exchange membrane. In this work, a new equipment for membrane-free PMFC is reported based on the optimization of the most expensive MFC components: the separator and the cathode. Using a revolving algae-bacteria biofilm cathode in a photosynthetic membrane-free microbial fuel cell (RAB-MFC) can obtain pollutants removal and algal biomass production as well as electrons generation. The highest chemical oxygen demand (COD) removal rates of the anode and cathode chambers reached 93.5 ± 2.6% and 95.8% ± 0.8%, respectively. The ammonia removal efficiency in anode and cathode chambers was 91.1 ± 1.3% and 98.0 ± 0.6%, respectively, corresponding to an ammonia removal rate of 0.92 ± 0.02 mg/L/h. The maximum current density and power density were 136.1 mA/m[2] and 33.1 mW/m[2]. The average biomass production of algae biofilm was higher than 30 g/m[2]. The 18S rDNA sequencing analysis the eukaryotic community and revealed high operational taxonomic units (OTUs) of Chlorophyta (44.43%) was dominant phyla with low COD level, while Ciliophora (54.36%) replaced Chlorophyta as the dominant phyla when COD increased. 16S rDNA high-throughput sequencing revealed that biofilms on the cathode contained a variety of prokaryote taxa, including Proteobacteria, Bacteroidota, Firmicutes, while there was only 0.23-0.26% photosynthesizing prokaryote found in the cathode biofilm. Collectively, this work demonstrated that RAB can be used as a bio-cathode in PMFC for pollutants removal from wastewater as well as electricity generation.}, } @article {pmid36299716, year = {2022}, author = {Yang, J and Zhang, Y and Chang, W and Lou, Y and Qian, H}, title = {Microbiologically influenced corrosion of FeCoNiCrMn high-entropy alloys by Pseudomonas aeruginosa biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1009310}, pmid = {36299716}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is widely found in industrial water and seawater. Microbiologically influenced corrosion (MIC) caused by P. aeruginosa is a serious threat and damage to the safe service of steel materials. In this study, the MIC behavior of FeCoNiCrMn high-entropy alloy (HEA) by P. aeruginosa biofilm was investigated in the simulated marine medium. The maximum pitting depth of the HEA coupons in the P. aeruginosa-inoculated medium was ~4.77 μm, which was 1.5 times that in the sterile medium. EIS and potentiodynamic polarization results indicated that P. aeruginosa biofilm reduced the corrosion resistance of the passive film of HEA coupons and promoted its anodic dissolution process. XPS and AES results further demonstrated that P. aeruginosa interfered with the distribution of elements in the passive film and significantly promoted the dissolution of Fe.}, } @article {pmid36297684, year = {2022}, author = {Aldossary, HA and Rehman, S and Jermy, BR and AlJindan, R and Aldayel, A and AbdulAzeez, S and Akhtar, S and Khan, FA and Borgio, JF and Al-Suhaimi, EA}, title = {Therapeutic Intervention for Various Hospital Setting Strains of Biofilm Forming Candida auris with Multiple Drug Resistance Mutations Using Nanomaterial Ag-Silicalite-1 Zeolite.}, journal = {Pharmaceutics}, volume = {14}, number = {10}, pages = {}, pmid = {36297684}, issn = {1999-4923}, support = {Grant No: 2021-182-IRMC//Deanship of Scientific Research, Imam Abdulrahman Bin Faisal University (To Ms. Hanan Aldossary, Grant No: 2021-182-IRMC)./ ; }, abstract = {Candida auris (C. auris), an emerging multidrug-resistant microorganism, with limited therapeutical options, is one of the leading causes of nosocomial infections. The current study includes 19 C. auris strains collected from King Fahd Hospital of the University and King Fahad Specialist Hospital in Dammam, identified by 18S rRNA gene and ITS region sequencing. Drug-resistance-associated mutations in ERG11, TAC1B and FUR1 genes were screened to gain insight into the pattern of drug resistance. Molecular identification was successfully achieved using 18S rRNA gene and ITS region and 5 drug-resistance-associated missense variants identified in the ERG11 (F132Y and K143R) and TAC1B (H608Y, P611S and A640V) genes of C. auris strains, grouped into 3 clades. The prophylactic and therapeutic application of hydrothermally synthesized Ag-silicalite-1 (Si/Ag ratio 25) nanomaterial was tested against the 3 clades of clinical C. auris strains. 4wt%Ag/TiZSM-5 prepared using conventional impregnation technique was used for comparative study, and nano formulations were characterized using different techniques. The antibiofilm activity of nanomaterials was tested by cell kill assay, scanning electron microscopy (SEM) and light microscopy. Across all the clades of C. auris strains, 4 wt%Ag/TiZSM-5 and Ag-silicalite-1 demonstrated a significant (p = 1.1102 × 10[-16]) inhibitory effect on the biofilm's survival rate: the lowest inhibition value was (10%) with Ag-silicalite-1 at 24 and 48 h incubation. A profound change in morphogenesis in addition to the reduction in the number of C.auris cells was shown by SEM and light microscopy. The presence of a high surface area and the uniform dispersion of nanosized Ag species displays enhanced anti-Candida activity, and therefore it has great potential against the emerging multidrug-resistant C. auris.}, } @article {pmid36297451, year = {2022}, author = {Alfei, S and Caviglia, D}, title = {Prevention and Eradication of Biofilm by Dendrimers: A Possibility Still Little Explored.}, journal = {Pharmaceutics}, volume = {14}, number = {10}, pages = {}, pmid = {36297451}, issn = {1999-4923}, abstract = {Multidrug resistance (MDR) among pathogens and the associated infections represent an escalating global public health problem that translates into raised mortality and healthcare costs. MDR bacteria, with both intrinsic abilities to resist antibiotics treatments and capabilities to transmit genetic material coding for further resistance to other bacteria, dramatically decrease the number of available effective antibiotics, especially in nosocomial environments. Moreover, the capability of several bacterial species to form biofilms (BFs) is an added alarming mechanism through which resistance develops. BF, made of bacterial communities organized and incorporated into an extracellular polymeric matrix, self-produced by bacteria, provides protection from the antibiotics' action, resulting in the antibiotic being ineffective. By adhering to living or abiotic surfaces present both in the environment and in the healthcare setting, BF causes the onset of difficult-to-eradicate infections, since it is difficult to prevent its formation and even more difficult to promote its disintegration. Inspired by natural antimicrobial peptides (NAMPs) acting as membrane disruptors, with a low tendency to develop resistance and demonstrated antibiofilm potentialities, cationic polymers and dendrimers, with similar or even higher potency than NAMPs and with low toxicity, have been developed, some of which have shown in vitro antibiofilm activity. Here, aiming to incite further development of new antibacterial agents capable of inhibiting BF formation and dispersing mature BF, we review all dendrimers developed to this end in the last fifteen years. The extension of the knowledge about these still little-explored materials could be a successful approach to find effective weapons for treating chronic infections and biomaterial-associated infections (BAIs) sustained by BF-producing MDR bacteria.}, } @article {pmid36297365, year = {2022}, author = {Bu, F and Liu, M and Xie, Z and Chen, X and Li, G and Wang, X}, title = {Targeted Anti-Biofilm Therapy: Dissecting Targets in the Biofilm Life Cycle.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {15}, number = {10}, pages = {}, pmid = {36297365}, issn = {1424-8247}, support = {21574008//National Natural Science Foundation of China/ ; }, abstract = {Biofilm is a crucial virulence factor for microorganisms that causes chronic infection. After biofilm formation, the bacteria present improve drug tolerance and multifactorial defense mechanisms, which impose significant challenges for the use of antimicrobials. This indicates the urgent need for new targeted technologies and emerging therapeutic strategies. In this review, we focus on the current biofilm-targeting strategies and those under development, including targeting persistent cells, quorum quenching, and phage therapy. We emphasize biofilm-targeting technologies that are supported by blocking the biofilm life cycle, providing a theoretical basis for design of targeting technology that disrupts the biofilm and promotes practical application of antibacterial materials.}, } @article {pmid36297234, year = {2022}, author = {Jiang, Q and Jing, Q and Ren, B and Cheng, L and Zhou, X and Lai, W and He, J and Li, M}, title = {Culture Supernatant of Enterococcus faecalis Promotes the Hyphal Morphogenesis and Biofilm Formation of Candida albicans.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36297234}, issn = {2076-0817}, support = {2021YFH0188//Science and Technology Department of Sichuan Province/ ; 81400501//National Natural Science Foundation of China/ ; 2017JQ0028//Science and Technology Department of Sichuan Province/ ; }, abstract = {(1) Background: Enterococcus faecalis and Candida albicans are often isolated from infected root canals. The interaction between these two species is not clear enough. Therefore, the objective of this study was to investigate the effect of E. faecalis on the biofilm formation, hyphal morphogenesis and virulence gene expression of C. albicans. (2) Methods: We used the culture supernatant of E. faecalis (CSE) to treat the biofilms of C. albicans. Then, crystal violet staining and colony-forming unit (CFU) counting were performed to evaluate biofilm biomass. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) were applied to observe fungal morphology. Subsequently, exopolymeric substances (EPS) production, cellular surface hydrophobicity (CSH) and adhesion force of biofilms were investigated by CLSM, water-hydrocarbon two-phase assay and atomic force microscopy (AFM), respectively. Finally, the expression of C. albicans virulence genes (ALS1, ALS3, HWP1 and EFG1) were measured by RT-qPCR assay. (3) Results: The exposure of CSE promoted the biofilm formation and hyphal morphogenesis of C. albicans, increased the EPS production, CSH and adhesion force of C. albicans biofilms, and increased the expression level of EFG1. (4) Conclusions: Our data indicated that CSE promoted the hyphal morphogenesis and biofilm formation of C. albicans.}, } @article {pmid36297193, year = {2022}, author = {Wang, L and Ji, C and Xia, X and Cai, X and Meng, Q and Qiao, J}, title = {A Regulatory SRNA Rli43 Is Involved in the Modulation of Biofilm Formation and Virulence in Listeria monocytogenes.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36297193}, issn = {2076-0817}, support = {No. 32160819, 31360596, 30960274//the National Natural Science Foundation of China/ ; No. 2016YFD0500900//the national key research and development program/ ; XJ2021G104//the Graduate student research innovation project of Xinjiang Autonomous region/ ; }, abstract = {Small RNAs (sRNAs) are a kind of regulatory molecule that can modulate gene expression at the post-transcriptional level, thereby involving alteration of the physiological characteristics of bacteria. However, the regulatory roles and mechanisms of most sRNAs remain unknown in Listeria monocytogenes(L. monocytogenes). To explore the regulatory roles of sRNA Rli43 in L. monocytogenes, the rli43 gene deletion strain LM-Δrli43 and complementation strain LM-Δrli43-rli43 were constructed to investigate the effects of Rli43 on responses to environmental stress, biofilm formation, and virulence, respectively. Additionally, Rli43-regulated target genes were identified using bioinformatic analysis tools and a bacterial dual plasmid reporter system based on E. coli. The results showed that the intracellular expression level of the rli43 gene was significantly upregulated compared with those under extracellular conditions. Compared with the parental and complementation strains, the environmental adaptation, motility, biofilm formation, adhesion, invasion, and intracellular survival of LM-Δrli43 were significantly reduced, respectively, whereas the LD50 of LM-Δrli43 was significantly elevated in BALB/c mice. Furthermore, the bacterial loads and pathological damages were alleviated, suggesting that sRNA Rli43 was involved in the modulation of the virulence of L. monocytogenes. It was confirmed that Rli43 may complementarily pair with the 5'-UTR (-47--55) of HtrA mRNA, thereby regulating the expression level of HtrA protein at the post-transcriptional level. These findings suggest that Rli43-mediated control was involved in the modulation of environmental adaptation, biofilm formation, and virulence in L. monocytogenes.}, } @article {pmid36297126, year = {2022}, author = {Silva, V and Pereira, JE and Maltez, L and Poeta, P and Igrejas, G}, title = {Influence of Environmental Factors on Biofilm Formation of Staphylococci Isolated from Wastewater and Surface Water.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36297126}, issn = {2076-0817}, support = {SFRH/BD/137947/2018//Fundação para a Ciência e Tecnologia/ ; }, abstract = {The presence of biofilms can negatively affect several different areas, such as the food industry, environment, and biomedical sectors. Conditions under which bacteria grow and develop, such as temperature, nutrients, and pH, among others, can largely influence biofilm production. Staphylococcus species survive in the natural environment due to their tolerance to a wide range of temperatures, dryness, dehydration, and low water activity. Therefore, we aimed to evaluate the influence of external environmental factors on the formation of biofilm of staphylococci isolated from hospital wastewater and surface waters. We investigated the biofilm formation of methicillin-resistant and -susceptible S. aureus (MRSA and MSSA) and coagulase-negative staphylococci (CoNS) under various temperatures, pH values, salt concentrations, glucose concentrations, and under anaerobic and aerobic conditions. CoNS had the ability to produce more biofilm biomass than MSSA and MRSA. All environmental factors studied influenced the biofilm formation of staphylococci isolates after 24 h of incubation. Higher biofilm formation was achieved at 4% of NaCl and 0.5% of glucose for MSSA and CoNS, and 1% of NaCl and 1.5% of glucose for MRSA isolates. Biofilm formation of isolates was greater at 25 °C and 37 °C than at 10 °C and 4 °C. pH values between 6 and 8 led to more robust biofilm formation than pH levels of 9 and 5. Although staphylococci are facultative anaerobes, biofilm formation was higher in the presence of oxygen. The results demonstrated that multiple environmental factors affect staphylococci biofilm formation. Different conditions affect differently the biofilm formation of MRSA, MSSA, and CoNS strains.}, } @article {pmid36296871, year = {2022}, author = {Hata, Y and Bouda, Y and Hiruma, S and Miyazaki, H and Nakamura, S}, title = {Biofilm Degradation by Seashell-Derived Calcium Hydroxide and Hydrogen Peroxide.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {20}, pages = {}, pmid = {36296871}, issn = {2079-4991}, support = {Not applicable//National Defense Medical College/ ; }, abstract = {Microbial cells and self-produced extracellular polymeric substances assembled to form biofilms that are difficult to remove from surfaces, causing problems in various fields. Seashell-derived calcium hydroxide, a sustainable inorganic material, has shown high bactericidal activity even for biofilms due to its alkalinity. However, its biofilm removal efficacy is relatively low. Herein, we report a biofilm degradation strategy that includes two environmentally friendly reagents: seashell-derived calcium hydroxide and hydrogen peroxide. A biofilm model of Escherichia coli was prepared in vitro, treated with calcium hydroxide-hydrogen peroxide solutions, and semi-quantified by the crystal violet stain method. The treatment significantly improved biofilm removal efficacy compared with treatments by calcium hydroxide alone and hydrogen peroxide alone. The mechanism was elucidated from calcium hydroxide-hydrogen peroxide solutions, which suggested that perhydroxyl anion and hydroxyl radical generated from hydrogen peroxide, as well as the alkalinity of calcium hydroxide, enhanced biofilm degradation. This study showed that concurrent use of other reagents, such as hydrogen peroxide, is a promising strategy for improving the biofilm degradation activity of seashell-derived calcium hydroxide and will contribute to developing efficient biofilm removal methods.}, } @article {pmid36296467, year = {2022}, author = {Mastoor, S and Nazim, F and Rizwan-Ul-Hasan, S and Ahmed, K and Khan, S and Ali, SN and Abidi, SH}, title = {Analysis of the Antimicrobial and Anti-Biofilm Activity of Natural Compounds and Their Analogues against Staphylococcus aureus Isolates.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {20}, pages = {}, pmid = {36296467}, issn = {1420-3049}, support = {Research Module funds and The Akbarali Habib Bandeali endowment funds//Aga Khan University/ ; Seed Funds//Hamdard University/ ; }, mesh = {Humans ; Staphylococcus aureus/physiology ; *Methicillin-Resistant Staphylococcus aureus/physiology ; Clindamycin/therapeutic use ; Amikacin ; Cephalothin/therapeutic use ; Eugenol/therapeutic use ; *Staphylococcal Infections/drug therapy ; Aldehydes ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Microbial Sensitivity Tests ; Ciprofloxacin/therapeutic use ; Gentamicins ; Ampicillin/therapeutic use ; Chloramphenicol/therapeutic use ; Streptomycin ; }, abstract = {(1) Background: Staphylococcus aureus (S. aureus) is one of the most frequent causes of biofilm-associated infections. With the emergence of antibiotic-resistant, especially methicillin-resistant S. aureus (MRSA), there is an urgent need to discover novel inhibitory compounds against this clinically important pathogen. In this study, we evaluated the antimicrobial and anti-biofilm activity of 11 compounds, including phenyl propenes and phenolic aldehydes, eugenol, ferulic acid, sinapic acid, salicylaldehyde, vanillin, cinnamoyl acid, and aldehydes, against drug-resistant S. aureus isolates. (2) Methods: Thirty-two clinical S. aureus isolates were obtained from Alkhidmat Diagnostic Center and Blood Bank, Karachi, Pakistan, and screened for biofilm-forming potential, and susceptibility/resistance against ciprofloxacin, chloramphenicol, ampicillin, amikacin, cephalothin, clindamycin, streptomycin, and gentamicin using the Kirby-Bauer disk diffusion method. Subsequently, 5 representative clinical isolates were selected and used to test the antimicrobial and anti-biofilm potential of 11 compounds using both qualitative and quantitative assays, followed by qPCR analysis to examine the differences in the expression levels of biofilm-forming genes (ica-A, fnb-B, clf-A and cna) in treated (with natural compounds and their derivatives) and untreated isolates. (3) Results: All isolates were found to be multi-drug resistant and dominant biofilm formers. The individual Minimum Inhibitory Concentration (MIC) of natural compounds and their analogues ranged from 0.75−160 mg/mL. Furthermore, the compounds, Salicylaldehyde (SALI), Vanillin (VAN), α-methyl-trans-cinnamaldehyde (A-MT), and trans-4-nitrocinnamic acid (T4N) exhibited significant (15−92%) biofilm inhibition/reduction percentage capacity at the concentration of 1−10 mg/mL. Gene expression analysis showed that salicylaldehyde, α-methyl-trans-cinnamaldehyde, and α-bromo-trans-cinnamaldehyde resulted in a significant (p < 0.05) downregulation of the expression of ica-A, clf-A, and fnb-A genes compared to the untreated resistant isolate. (4) Conclusions: The natural compounds and their analogues used in this study exhibited significant antimicrobial and anti-biofilm activity against S. aureus. Biofilms persist as the main concern in clinical settings. These compounds may serve as potential candidate drug molecules against biofilm forming S. aureus.}, } @article {pmid36296427, year = {2022}, author = {Hrichi, S and Chaâbane-Banaoues, R and Alibrando, F and Altemimi, AB and Babba, O and Majdoub, YOE and Nasri, H and Mondello, L and Babba, H and Mighri, Z and Cacciola, F}, title = {Chemical Composition, Antifungal and Anti-Biofilm Activities of Volatile Fractions of Convolvulus althaeoides L. Roots from Tunisia.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {20}, pages = {}, pmid = {36296427}, issn = {1420-3049}, mesh = {*Antifungal Agents/pharmacology/chemistry ; *Convolvulus ; Hexanes ; Chloroform ; Linoleic Acid ; Tunisia ; Gas Chromatography-Mass Spectrometry ; Biofilms ; Candida albicans ; Candida tropicalis ; Microbial Sensitivity Tests ; Candida glabrata ; Adipates ; Guaiacol ; Benzyl Alcohols ; }, abstract = {The antifungal drugs currently available and mostly used for the treatment of candidiasis exhibit the phenomena of toxicity and increasing resistance. In this context, plant materials might represent promising sources of antifungal agents. The aim of this study is to evaluate for the first time the chemical content of the volatile fractions (VFs) along with the antifungal and anti-biofilm of Convolvulus althaeoides L. roots. The chemical composition was determined by gas chromatography coupled to a flame ionization detector and mass spectrometry. In total, 73 and 86 chemical compounds were detected in the n-hexane (VF1) and chloroform (VF2) fractions, respectively. Analysis revealed the presence of four main compounds: n-hexadecenoic acid (29.77%), 4-vinyl guaiacol (12.2%), bis(2-ethylhexyl)-adipate (9.69%) and eicosane (3.98%) in the VF extracted by hexane (VF1). n-hexadecenoic acid (34.04%), benzyl alcohol (7.86%) and linoleic acid (7.30%) were the main compounds found in the VF extracted with chloroform (VF2). The antifungal minimum inhibitory concentrations (MICs) of the obtained fractions against Candida albicans, Candida glabrata and Candida tropicalis were determined by the micro-dilution technique and values against Candida spp. ranged from 0.87 to 3.5 mg/mL. The biofilm inhibitory concentrations (IBF) and sustained inhibition (BSI) assays on C. albicans, C. glabrata and C. tropicalis were also investigated. The VFs inhibited biofilm formation up to 0.87 mg/mL for C. albicans, up to 1.75 mg/mL against C. glabrata and up to 0.87 mg/mL against C. tropicalis. The obtained results highlighted the synergistic mechanism of the detected molecules in the prevention of candidosic biofilm formation.}, } @article {pmid36296367, year = {2022}, author = {Parolin, C and Croatti, V and Giordani, B and Vitali, B}, title = {Vaginal Lactobacillus Impair Candida Dimorphic Switching and Biofilm Formation.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296367}, issn = {2076-2607}, abstract = {Lactobacillus spp. generally dominate the vaginal microbiota and prevent pathogen adhesion and overgrowth, including Candida spp., by various mechanisms. Although Candida spp. can be commensal, in certain conditions they can become pathogenic, causing vulvovaginal candidiasis. The insurgence of candidiasis is related to the expression of Candida virulence factors, including morphologic switching and biofilm formation. Germ tubes, pseudohyphae, and hyphae promote Candida tissue invasion, biofilms increase persistence and are often resistant to antifungals and host immune response. Here, we explored the inhibitory activity of vaginal Lactobacillus strains belonging to Lactobacillus crispatus, Lactobacillus gasseri, Limosilactobacillus vaginalis, and Lactiplantibacillus plantarum species towards Candida virulence factors. With the aim to investigate the interrelation between mode of growth and functionality, supernatants were collected from lactobacilli planktonic cultures and, for the first time, from adherent ones, and were evaluated towards Candida dimorphic switching and biofilm. Candida biofilms were analyzed by multiple methodologies, i.e., crystal violet staining, MTT assay, and confocal microscopy. Lactobacillus supernatants reduce Candida switching and biofilm formation. Importantly, L. crispatus supernatants showed the best profile of virulence suppression, especially when grown in adherence. These results highlight the role of such species as a hallmark of vaginal eubiosis and prompt its employment in new probiotics for women's health.}, } @article {pmid36296307, year = {2022}, author = {Elgamoudi, BA and Starr, KS and Korolik, V}, title = {Extracellular c-di-GMP Plays a Role in Biofilm Formation and Dispersion of Campylobacter jejuni.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296307}, issn = {2076-2607}, abstract = {Cyclic diguanosine monophosphate (c-diGMP) is a ubiquitous second messenger involved in the regulation of many signalling systems in bacteria, including motility and biofilm formation. Recently, it has been reported that c-di-GMP was detected in C. jejuni DRH212; however, the presence and the role of c-di-GMP in other C. jejuni strains are unknown. Here, we investigated extracellular c-di-GMP as an environmental signal that potentially triggers biofilm formation in C. jejuni NCTC 11168 using a crystal violet-based assay, motility-based plate assay, RT-PCR and confocal laser scanning microscopy (CLSM). We found that, in presence of extracellular c-di-GMP, the biofilm formation was significantly reduced (>50%) and biofilm dispersion enhanced (up to 60%) with no effect on growth. In addition, the presence of extracellular c-di-GMP promoted chemotactic motility, inhibited the adherence of C. jejuni NCTC 11168-O to Caco-2 cells and upregulated the expression of Cj1198 (luxS, encoding quarum sensing pathway component, autoinducer-2), as well as chemotaxis genes Cj0284c (cheA) and Cj0448c (tlp6). Unexpectedly, the expression of Cj0643 (cbrR), containing a GGDEF-like domain and recently identified as a potential diguanylate cyclase gene, required for the synthesis of c-di-GMP, was not affected. Our findings suggest that extracellular c-di-GMP could be involved in C. jejuni gene regulation, sensing and biofilm dispersion.}, } @article {pmid36296303, year = {2022}, author = {Reddersen, K and Tittelbach, J and Wiegand, C}, title = {3D Biofilm Models Containing Multiple Species for Antimicrobial Testing of Wound Dressings.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296303}, issn = {2076-2607}, abstract = {The treatment of chronic wounds presents a major challenge in medical care. In particular, the effective treatment of bacterial infections that occur in the form of biofilms is of crucial importance. To develop successful antibiofilm strategies for chronic wound treatment, biofilm models are needed that resemble the in vivo situation, are easy to handle, standardizable, and where results are readily transferable to the clinical situation. We established two 3D biofilm models to distinguish the effectiveness of wound dressings on important microorganisms present in chronic wounds. The first 3D biofilm model contains Staphylococcus aureus, Escherichia coli, and Acinetobacter baumannii, while the second is based on Pseudomonas aeruginosa. Bacteria are cultivated in a nutrient-rich agar/gelatin mix, into which air bubbles are incorporated. This results in a mature biofilm growing in clusters similar to its organization in chronic wounds. The models are convenient to use, have low variability and are easy to establish in the laboratory. Treatment with polihexanide and silver-containing wound dressings showed that the models are very well suited for antimicrobial testing and that they can detect differences in the efficacy of antimicrobial substances. Therefore, these models present valuable tools in the development of effective antibiofilm strategies in chronic wounds.}, } @article {pmid36296280, year = {2022}, author = {Carmona-Torre, F and Fernández-Ciriza, L and Berniz, C and Gomez-Martinez de Lecea, C and Ramos, A and Hontanilla, B and Del Pozo, JL}, title = {An Experimental Murine Model to Assess Biofilm Persistence on Commercial Breast Implant Surfaces.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296280}, issn = {2076-2607}, support = {PI17/00974//Instituto de Salud Carlos III/ ; }, abstract = {Capsular contracture is the most frequently associated complication following breast implant placement. Biofilm formation on the surface of such implants could significantly influence the pathogenesis of this complication. The objective of this study was to design an experimental model of breast implant infection that allowed us to compare the in vivo S. epidermidis ability to form and perpetuate biofilms on commonly used types of breast implants (i.e., macrotexturized, microtexturized, and smooth). A biofilm forming S. epidermidis strain (ATCC 35984) was used for all experiments. Three different implant surface types were tested: McGhan BIOCELL® (i.e., macrotexturized); Mentor Siltex® (i.e., microtexturized); and Allergan Natrelle Smooth® (i.e., smooth). Two different infection scenarios were simulated. The ability to form biofilm on capsules and implants over time was evaluated by quantitative post-sonication culture of implants and capsules biopsies. This experimental model allows the generation of a subclinical staphylococcal infection associated with a breast implant placed in the subcutaneous tissue of Wistar rats. The probability of generating an infection was different according to the type of implant studied and to the time from implantation to implant removal. Infection was achieved in 88.9% of macrotextured implants (i.e., McGhan), 37.0% of microtexturized implants (i.e., Mentor), and 18.5% of smooth implants (i.e., Allergan Smooth) in the short-term (p < 0.001). Infection was achieved in 47.2% of macrotextured implants, 2.8% of microtexturized implants, and 2.8% of smooth implants (i.e., Allergan Smooth) in the long-term (p < 0.001). There was a clear positive correlation between biofilm formation on any type of implant and capsule colonization/infection. Uniformly, the capsules formed around the macro- or microtexturized implants were consistently macroscopically thicker than those formed around the smooth implants regardless of the time at which they were removed (i.e., 1−2 weeks or 3−5 weeks). We have shown that there is a difference in the ability of S epidermidis to develop in vivo biofilms on macrotextured, microtextured, and smooth implants. Smooth implants clearly thwart bacterial adherence and, consequently, biofilm formation and persistence are hindered.}, } @article {pmid36296251, year = {2022}, author = {Mohamed, HMA and Alnasser, SM and Abd-Elhafeez, HH and Alotaibi, M and Batiha, GE and Younis, W}, title = {Detection of β-Lactamase Resistance and Biofilm Genes in Pseudomonas Species Isolated from Chickens.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296251}, issn = {2076-2607}, support = {TURSP-2020/202//Taif University Researchers Supporting Project/ ; }, abstract = {Bacteria of the genus Pseudomonas are pathogens in both humans and animals. The most prevalent nosocomial pathogen is P. aeruginosa, particularly strains with elevated antibiotic resistance. In this study, a total of eighteen previously identified Pseudomonas species strains, were isolated from chicken. These strains were screened for biofilm formation and antibiotic resistance. In addition, we evaluated clove oil’s effectiveness against Pseudomonas isolates as an antibiofilm agent. The results showed that Pseudomonas species isolates were resistant to most antibiotics tested, particularly those from the β-lactamase family. A significant correlation (p < 0.05) between the development of multidrug-resistant isolates and biofilms is too informal. After amplifying the AmpC-plasmid-mediated genes (blaCMY, blaMIR, DHA, and FOX) and biofilm-related genes (psld, rhlA, and pelA) in most of our isolates, PCR confirmed this relationship. Clove oil has a potent antibiofilm effect against Pseudomonas isolates, and may provide a treatment for bacteria that form biofilms and are resistant to antimicrobials.}, } @article {pmid36296200, year = {2022}, author = {Sekoai, PT and Chunilall, V and Sithole, B and Habimana, O and Ndlovu, S and Ezeokoli, OT and Sharma, P and Yoro, KO}, title = {Elucidating the Role of Biofilm-Forming Microbial Communities in Fermentative Biohydrogen Process: An Overview.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296200}, issn = {2076-2607}, abstract = {Amongst the biofuels described in the literature, biohydrogen has gained heightened attention over the past decade due to its remarkable properties. Biohydrogen is a renewable form of H2 that can be produced under ambient conditions and at a low cost from biomass residues. Innovative approaches are continuously being applied to overcome the low process yields and pave the way for its scalability. Since the process primarily depends on the biohydrogen-producing bacteria, there is a need to acquire in-depth knowledge about the ecology of the various assemblages participating in the process, establishing effective bioaugmentation methods. This work provides an overview of the biofilm-forming communities during H2 production by mixed cultures and the synergistic associations established by certain species during H2 production. The strategies that enhance the growth of biofilms within the H2 reactors are also discussed. A short section is also included, explaining techniques used for examining and studying these biofilm structures. The work concludes with some suggestions that could lead to breakthroughs in this area of research.}, } @article {pmid36296197, year = {2022}, author = {Gaviria-Cantin, T and Vargas, AF and Mouali, YE and Jiménez, CJ and Cimdins-Ahne, A and Madrid, C and Römling, U and Balsalobre, C}, title = {Gre Factors Are Required for Biofilm Formation in Salmonella enterica Serovar Typhimurium by Targeting Transcription of the csgD Gene.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296197}, issn = {2076-2607}, support = {AGL2013-45339R//Spanish MInistry of Economy and Competitiveness/ ; PGC2018-096958-B-I00//Spanish MInistry of Science, Innovation and Universities/ ; 621-2013-4809//Swedish Research Council/ ; 2017-04465//Swedish Research Council/ ; 2017SGR499//Catalonian Government/ ; CI239/1-1//Deutsche Forschungsgemeinschaft/ ; CI 239/2-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Rdar biofilm formation of Salmonella typhimurium and Escherichia coli is a common ancient multicellular behavior relevant in cell-cell and inter-organism interactions equally, as in interaction with biotic and abiotic surfaces. With the expression of the characteristic extracellular matrix components amyloid curli fimbriae and the exopolysaccharide cellulose, the central hub for the delicate regulation of rdar morphotype expression is the orphan transcriptional regulator CsgD. Gre factors are ubiquitously interacting with RNA polymerase to selectively overcome transcriptional pausing. In this work, we found that GreA/GreB are required for expression of the csgD operon and consequently the rdar morphotype. The ability of the Gre factors to suppress transcriptional pausing and the 147 bp 5'-UTR of csgD are required for the stimulatory effect of the Gre factors on csgD expression. These novel mechanism(s) of regulation for the csgD operon might be relevant under specific stress conditions.}, } @article {pmid36296183, year = {2022}, author = {Lu, Y and Cai, WJ and Ren, Z and Han, P}, title = {The Role of Staphylococcal Biofilm on the Surface of Implants in Orthopedic Infection.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296183}, issn = {2076-2607}, support = {(81974325//the National Natural Science Foundation of China/ ; }, abstract = {Despite advanced implant sterilization and aseptic surgical techniques, implant-associated infection remains a major challenge for orthopedic surgeries. The subject of bacterial biofilms is receiving increasing attention, probably as a result of the wide acknowledgement of the ubiquity of biofilms in the clinical environment, as well as the extreme difficulty in eradicating them. Biofilm can be defined as a structured microbial community of cells that are attached to a substratum and embedded in a matrix of extracellular polymeric substances (EPS) that they have produced. Biofilm development has been proposed as occurring in a multi-step process: (i) attachment and adherence, (ii) accumulation/maturation due to cellular aggregation and EPS production, and (iii) biofilm detachment (also called dispersal) of bacterial cells. In all these stages, characteristic proteinaceous and non-proteinaceous compounds are expressed, and their expression is strictly controlled. Bacterial biofilm formation around implants shelters the bacteria and encourages the persistence of infection, which could lead to implant failure and osteomyelitis. These complications need to be treated by major revision surgeries and extended antibiotic therapies, which could lead to high treatment costs and even increase mortality. Effective preventive and therapeutic measures to reduce risks for implant-associated infections are thus in urgent need.}, } @article {pmid36296179, year = {2022}, author = {Roy, PK and Song, MG and Jeon, EB and Kim, SH and Park, SY}, title = {Antibiofilm Efficacy of Quercetin against Vibrio parahaemolyticus Biofilm on Food-Contact Surfaces in the Food Industry.}, journal = {Microorganisms}, volume = {10}, number = {10}, pages = {}, pmid = {36296179}, issn = {2076-2607}, support = {2021R1I1A3A04037468//National Research Foundation of Korea/ ; }, abstract = {Vibrio parahaemolyticus, one of the most common foodborne pathogenic bacteria that forms biofilms, is a persistent source of concern for the food industry. The food production chain employs a variety of methods to control biofilms, although none are completely successful. This study aims to evaluate the effectiveness of quercetin as a food additive in reducing V. parahaemolyticus biofilm formation on stainless-steel coupons (SS) and hand gloves (HG) as well as testing its antimicrobial activities. With a minimum inhibitory concentration (MIC) of 220 µg/mL, the tested quercetin exhibited the lowest bactericidal action without visible growth. In contrast, during various experiments in this work, the inhibitory efficacy of quercetin at sub-MICs levels (1/2, 1/4, and 1/8 MIC) against V. parahaemolyticus was examined. Control group was not added with quercetin. With increasing quercetin concentration, swarming and swimming motility, biofilm formation, and expression levels of target genes linked to flagellar motility (flaA, flgL), biofilm formation (vp0952, vp0962), virulence (VopQ, vp0450), and quorum-sensing (aphA, luxS) were all dramatically suppressed. Quercetin (0−110 μg/mL) was investigated on SS and HG surfaces, the inhibitory effect were 0.10−2.17 and 0.26−2.31 log CFU/cm2, respectively (p < 0.05). Field emission scanning electron microscopy (FE-SEM) corroborated the findings because quercetin prevented the development of biofilms by severing cell-to-cell contacts and inducing cell lysis, which resulted in the loss of normal cell shape. Additionally, there was a significant difference between the treated and control groups in terms of motility (swimming and swarming). According to our research, quercetin produced from plants should be employed as an antibiofilm agent in the food sector to prevent the growth of V. parahaemolyticus biofilms. These results indicate that throughout the entire food production chain, bacterial targets are of interest for biofilm reduction with alternative natural food agents in the seafood industry.}, } @article {pmid36295687, year = {2022}, author = {Zahidullah, and Siddiqui, MF and Tabraiz, S and Maqbool, F and Adnan, F and Ullah, I and Shah, MA and Jadoon, WA and Mehmood, T and Qayyum, S and Rahman, Z}, title = {Targeting Microbial Biofouling by Controlling Biofilm Formation and Dispersal Using Rhamnolipids on RO Membrane.}, journal = {Membranes}, volume = {12}, number = {10}, pages = {}, pmid = {36295687}, issn = {2077-0375}, support = {7182//Higher Education Commission/ ; }, abstract = {Finding new biological ways to control biofouling of the membrane in reverse osmosis (RO) is an important substitute for synthetic chemicals in the water industry. Here, the study was focused on the antimicrobial, biofilm formation, and biofilm dispersal potential of rhamnolipids (RLs) (biosurfactants). The MTT assay was also carried out to evaluate the effect of RLs on biofilm viability. Biofilm was qualitatively and quantitatively assessed by crystal violet assay, light microscopy, fluorescence microscopy (bacterial biomass (µm2), surface coverage (%)), and extracellular polymeric substances (EPSs). It was exhibited that RLs can reduce bacterial growth. The higher concentrations (≥100 mg/L) markedly reduced bacterial growth and biofilm formation, while RLs exhibited substantial dispersal effects (89.10% reduction) on preformed biofilms. Further, RLs exhibited 79.24% biomass reduction while polysaccharide was reduced to 60.55 µg/mL (p < 0.05) and protein to 4.67 µg/mL (p < 0.05). Light microscopy revealed biofilm reduction, which was confirmed using fluorescence microscopy. Microscopic images were processed with BioImageL software. It was revealed that biomass surface coverage was reduced to 1.1% at 1000 mg/L of RLs and that 43,245 µm2 of biomass was present for control, while biomass was reduced to 493 µm2 at 1000 mg/L of RLs. Thus, these data suggest that RLs have antimicrobial, biofilm control, and dispersal potential against membrane biofouling.}, } @article {pmid36295125, year = {2022}, author = {Łysik, D and Deptuła, P and Chmielewska, S and Bucki, R and Mystkowska, J}, title = {Degradation of Polylactide and Polycaprolactone as a Result of Biofilm Formation Assessed under Experimental Conditions Simulating the Oral Cavity Environment.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {20}, pages = {}, pmid = {36295125}, issn = {1996-1944}, abstract = {Polylactide (PLA) and polycaprolactone (PCL) are biodegradable and bioabsorbable thermoplastic polymers considered as promising materials for oral applications. However, any abiotic surface used, especially in areas naturally colonized by microorganisms, provides a favorable interface for microbial growth and biofilm development. In this study, we investigated the biofilm formation of C. krusei and S. mutans on the surface of PLA and PCL immersed in the artificial saliva. Using microscopic (AFM, CLSM) observations and spectrometric measurements, we assessed the mass and topography of biofilm that developed on PLA and PCL surfaces. Incubated up to 56 days in specially prepared saliva and microorganisms medium, solid polymer samples were examined for surface properties (wettability, roughness, elastic modulus of the surface layer), structure (molecular weight, crystallinity), and mechanical properties (hardness, tensile strength). It has been shown that biofilm, especially S. mutans, promotes polymer degradation. Our findings indicate the need for additional antimicrobial strategies for the effective oral applications of PLA and PCL.}, } @article {pmid36294614, year = {2022}, author = {Pistoia, ES and Cosio, T and Campione, E and Pica, F and Volpe, A and Marino, D and Di Francesco, P and Monari, C and Fontana, C and Favaro, M and Zampini, P and Orlandi, A and Gaziano, R}, title = {All-Trans Retinoic Acid Effect on Candida albicans Growth and Biofilm Formation.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {10}, pages = {}, pmid = {36294614}, issn = {2309-608X}, support = {CUP: E89C20000740005//University of Rome Tor Vergata/ ; }, abstract = {UNLABELLED: Candida albicans (C. albicans) is the most common fungal pathogen causing recurrent mucosal and life-threatening systemic infections. The ability to switch from yeast to hyphae and produce biofilm are the key virulence determinants of this fungus. In fact, Candida biofilms on medical devices represent the major risk factor for nosocomial bloodstream infections. Novel antifungal strategies are required given the severity of systemic candidiasis, especially in immunocompromised patients, and the lack of effective anti-biofilm treatments. Retinoids have gained attention recently due to their antifungal properties.

MATERIAL AND METHODS: The present study aimed at evaluating the in vitro effects of different concentrations (300 to 18.75 µg/mL) of All-trans Retinoic Acid (ATRA), a vitamin A metabolite, on Candida growth and biofilm formation.

RESULTS: ATRA completely inhibited the fungal growth, by acting as both fungicidal (at 300 µg/mL) and fungistatic (at 150 µg/mL) agent. Furthermore, ATRA was found to negatively affect Candida biofilm formation in terms of biomass, metabolic activity and morphology, in a dose-dependent manner, and intriguingly, its efficacy was as that of amphotericin B (AmB) (2-0.12 μg/mL). Additionally, transmission electron microscopy (TEM) analysis showed that at 300 μg/mL ATRA induced plasma membrane damage in Candida cells, confirming its direct toxic effect against the fungus.

CONCLUSION: Altogether, the results suggest that ATRA has a potential for novel antifungal strategies aimed at preventing and controlling biofilm-associated Candida infections.}, } @article {pmid36294579, year = {2022}, author = {Pokhrel, S and Boonmee, N and Tulyaprawat, O and Pharkjaksu, S and Thaipisutikul, I and Chairatana, P and Ngamskulrungroj, P and Mitrpant, C}, title = {Assessment of Biofilm Formation by Candida albicans Strains Isolated from Hemocultures and Their Role in Pathogenesis in the Zebrafish Model.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {10}, pages = {}, pmid = {36294579}, issn = {2309-608X}, support = {R016333017//Mahidol University/ ; }, abstract = {Candida albicans, an opportunistic pathogen, has the ability to form biofilms in the host or within medical devices in the body. Biofilms have been associated with disseminated/invasive disease with increased severity of infection by disrupting the host immune response and prolonging antifungal treatment. In this study, the in vivo virulence of three strains with different biofilm formation strengths, that is, non-, weak-, and strong biofilm formers, was evaluated using the zebrafish model. The survival assay and fungal tissue burden were measured. Biofilm-related gene expressions were also investigated. The survival of zebrafish, inoculated with strong biofilms forming C. albicans,, was significantly shorter than strains without biofilms forming C. albicans. However, there were no statistical differences in the burden of viable colonogenic cell number between the groups of the three strains tested. We observed that the stronger the biofilm formation, the higher up-regulation of biofilm-associated genes. The biofilm-forming strain (140 and 57), injected into zebrafish larvae, possessed a higher level of expression of genes associated with adhesion, attachment, filamentation, and cell proliferation, including eap1, als3, hwp1, bcr1, and mkc1 at 8 h. The results suggested that, despite the difference in genetic background, biofilm formation is an important virulence factor for the pathogenesis of C. albicans. However, the association between biofilm formation strength and in vivo virulence is controversial and needs to be further studied.}, } @article {pmid36294577, year = {2022}, author = {Toure, S and Millot, M and Ory, L and Roullier, C and Khaldi, Z and Pichon, V and Girardot, M and Imbert, C and Mambu, L}, title = {Access to Anti-Biofilm Compounds from Endolichenic Fungi Using a Bioguided Networking Screening.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {10}, pages = {}, pmid = {36294577}, issn = {2309-608X}, support = {ANR-17-CE35-0005//Agence Nationale de la Recherche/ ; 2015-2020 State-Region Planning Contract//European Regional Development Fund/ ; }, abstract = {Endolichenic microorganisms represent a new source of bioactive natural compounds. Lichens, resulting from a symbiotic association between algae or cyanobacteria and fungi, constitute an original ecological niche for these microorganisms. Endolichenic fungi inhabiting inside the lichen thallus have been isolated and characterized. By cultivation on three different culture media, endolichenic fungi gave rise to a wide diversity of bioactive metabolites. A total of 38 extracts were screened for their anti-maturation effect on Candida albicans biofilms. The 10 most active ones, inducing at least 50% inhibition, were tested against 24 h preformed biofilms of C. albicans, using a reference strain and clinical isolates. The global molecular network was associated to bioactivity data in order to identify and priorize active natural product families. The MS-targeted isolation led to the identification of new oxygenated fatty acid in Preussia persica endowed with an interesting anti-biofilm activity against C. albicans yeasts.}, } @article {pmid36293559, year = {2022}, author = {Shenkutie, AM and Zhang, J and Yao, M and Asrat, D and Chow, FWN and Leung, PHM}, title = {Effects of Sub-Minimum Inhibitory Concentrations of Imipenem and Colistin on Expression of Biofilm-Specific Antibiotic Resistance and Virulence Genes in Acinetobacter baumannii Sequence Type 1894.}, journal = {International journal of molecular sciences}, volume = {23}, number = {20}, pages = {}, pmid = {36293559}, issn = {1422-0067}, support = {PH16-01625//the Hong Kong PhD Fellowship Scheme/ ; }, mesh = {Humans ; *Acinetobacter baumannii ; Colistin/pharmacology/therapeutic use ; Imipenem/pharmacology/therapeutic use ; *Acinetobacter Infections/drug therapy ; Virulence ; DNA Gyrase ; Microbial Sensitivity Tests ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Drug Resistance, Multiple, Bacterial/genetics ; }, abstract = {Antibiotics at suboptimal doses promote biofilm formation and the development of antibiotic resistance. The underlying molecular mechanisms, however, were not investigated. Here, we report the effects of sub-minimum inhibitory concentrations (sub-MICs) of imipenem and colistin on genes associated with biofilm formation and biofilm-specific antibiotic resistance in a multidrug-tolerant clinical strain of Acinetobacter baumannii Sequence Type (ST) 1894. Comparative transcriptome analysis was performed in untreated biofilm and biofilm treated with sub-MIC doses of imipenem and colistin. RNA sequencing data showed that 78 and 285 genes were differentially expressed in imipenem and colistin-treated biofilm cells, respectively. Among the differentially expressed genes (DEGs), 48 and 197 genes were upregulated exclusively in imipenem and colistin-treated biofilm cells, respectively. The upregulated genes included those encoding matrix synthesis (pgaB), multidrug efflux pump (novel00738), fimbrial proteins, and homoserine lactone synthase (AbaI). Upregulation of biofilm-associated genes might enhance biofilm formation when treated with sub-MICs of antibiotics. The downregulated genes include those encoding DNA gyrase (novel00171), 30S ribosomal protein S20 (novel00584), and ribosome releasing factor (RRF) were downregulated when the biofilm cells were treated with imipenem and colistin. Downregulation of these genes affects protein synthesis, which in turn slows down cell metabolism and makes biofilm cells more tolerant to antibiotics. In this investigation, we also found that 5 of 138 small RNAs (sRNAs) were differentially expressed in biofilm regardless of antibiotic treatment or not. Of these, sRNA00203 showed the highest expression levels in biofilm. sRNAs regulate gene expression and are associated with biofilm formation, which may in turn affect the expression of biofilm-specific antibiotic resistance. In summary, when biofilm cells were exposed to sub-MIC doses of colistin and imipenem, coordinated gene responses result in increased biofilm production, multidrug efflux pump expression, and the slowdown of metabolism, which leads to drug tolerance in biofilm. Targeting antibiotic-induced or repressed biofilm-specific genes represents a new strategy for the development of innovative and effective treatments for biofilm-associated infections caused by A. baumannii.}, } @article {pmid36293092, year = {2022}, author = {Rahman, MA and Amirkhani, A and Parvin, F and Chowdhury, D and Molloy, MP and Deva, AK and Vickery, K and Hu, H}, title = {One Step Forward with Dry Surface Biofilm (DSB) of Staphylococcus aureus: TMT-Based Quantitative Proteomic Analysis Reveals Proteomic Shifts between DSB and Hydrated Biofilm.}, journal = {International journal of molecular sciences}, volume = {23}, number = {20}, pages = {}, pmid = {36293092}, issn = {1422-0067}, mesh = {Humans ; *Staphylococcus aureus ; Proteomics ; Argininosuccinate Synthase ; DNA Breaks, Double-Stranded ; Peptidoglycan ; Biofilms ; *Staphylococcal Infections ; Glucosamine ; Transferases ; ATP-Binding Cassette Transporters ; Glucose Transport Proteins, Facilitative ; Transaminases ; Alanine ; Uridine Diphosphate ; }, abstract = {The Gram-positive bacterium Staphylococcus aureus is responsible for serious acute and chronic infections worldwide and is well-known for its biofilm formation ability. Recent findings of biofilms on dry hospital surfaces emphasise the failures in current cleaning practices and disinfection and the difficulty in removing these dry surface biofilms (DSBs). Many aspects of the formation of complex DSB biology on environmental surfaces in healthcare settings remains limited. In the present study, we aimed to determine how the protein component varied between DSBs and traditional hydrated biofilm. To do this, biofilms were grown in tryptic soy broth (TSB) on removable polycarbonate coupons in the CDC biofilm reactor over 12 days. Hydrated biofilm (50% TSB for 48 h, the media was then changed every 48 h with 20% TSB, at 37 °C with 130 rpm). DSB biofilm was produced in 5% TSB for 48 h at 35 °C followed by extended periods of dehydration (48, 66, 42 and 66 h at room temperature) interspersed with 6 h of 5% TSB at 35 °C. Then, we constructed a comprehensive reference map of 12-day DSB and 12-day hydrated biofilm associated proteins of S. aureus using a high-throughput tandem mass tag (TMT)-based mass spectrometry. Further pathway analysis of significantly differentially expressed identified proteins revealed that proteins significantly upregulated in 12-day DSB include PTS glucose transporter subunit IIBC (PtaA), UDP-N-acetylmuramate-L-alanine ligase (MurC) and UDP-N-acetylenolpyruvoylglucosamine (MurB) compared to 12-day hydrated biofilm. These three proteins are all linked with peptidoglycan biosynthesis pathway and are responsible for cell-wall formation and thicker EPS matrix deposition. Increased cell-wall formation may contribute to the persistence of DSB on dry surfaces. In contrast, proteins associated with energy metabolisms such as phosphoribosyl transferase (PyrR), glucosamine--fructose-6-phosphate aminotransferase (GlmS), galactose-6-phosphate isomerase (LacA), and argininosuccinate synthase (ArgG) were significantly upregulated whereas ribosomal and ABC transporters were significantly downregulated in the 12-day hydrated biofilm compared to DSB. However, validation by qPCR analysis showed that the levels of gene expression identified were only partially in line with our TMT-MS quantitation analysis. For the first time, a TMT-based proteomics study with DSB has shed novel insights and provided a basis for the identification and study of significant pathways vital for biofilm biology in this reference microorganism.}, } @article {pmid36290543, year = {2022}, author = {Luo, K and Guo, X and Zhang, H and Fu, H and Wang, J}, title = {The Physiological Functions of AbrB on Sporulation, Biofilm Formation and Carbon Source Utilization in Clostridium tyrobutyricum.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {36290543}, issn = {2306-5354}, support = {2019A050510008//Science and Technology Planning Project of Guangdong Province of China/ ; 22178133//National Natural Science Foundation of China/ ; }, abstract = {As a pleiotropic regulator, Antibiotic resistant protein B (AbrB) was reported to play important roles in various cellular processes in Bacilli and some Clostridia strains. In Clostridium tyrobutyricum, abrB (CTK_C 00640) was identified to encode AbrB by amino acid sequence alignment and functional domain prediction. The results of abrB deletion or overexpression in C. tyrobutyricum showed that AbrB not only exhibited the reported characteristics such as the negative regulation on sporulation, positive effects on biofilm formation and stress resistance but also exhibited new functions, especially the negative regulation of carbon metabolism. AbrB knockout strain (Ct/ΔabrB) could alleviate glucose-mediated carbon catabolite repression (CCR) and enhance the utilization of xylose compared with the parental strain, resulting in a higher butyrate titer (14.79 g/L vs. 7.91 g/L) and xylose utilization rate (0.19 g/L·h vs. 0.02 g/L·h) from the glucose and xylose mixture. This study confirmed the pleiotropic regulatory function of AbrB in C. tyrobutyricum, suggesting that Ct/ΔabrB was the potential candidate for butyrate production from abundant, renewable lignocellulosic biomass mainly composed of glucose and xylose.}, } @article {pmid36290325, year = {2022}, author = {Vishnyakova, A and Popova, N and Artemiev, G and Botchkova, E and Litti, Y and Safonov, A}, title = {Effect of Mineral Carriers on Biofilm Formation and Nitrogen Removal Activity by an Indigenous Anammox Community from Cold Groundwater Ecosystem Alone and Bioaugmented with Biomass from a "Warm" Anammox Reactor.}, journal = {Biology}, volume = {11}, number = {10}, pages = {}, pmid = {36290325}, issn = {2079-7737}, support = {22-24-00701//Russian Science Foundation/ ; }, abstract = {The complex pollution of aquifers by reduced and oxidized nitrogen compounds is currently considered one of the urgent environmental problems that require non-standard solutions. This work was a laboratory-scale trial to show the feasibility of using various mineral carriers to create a permeable in situ barrier in cold (10 °C) aquifers with extremely high nitrogen pollution and inhabited by the Candidatus Scalindua-dominated indigenous anammox community. It has been established that for the removal of ammonium and nitrite in situ due to the predominant contribution of the anammox process, quartz, kaolin clays of the Kantatsky and Kamalinsky deposits, bentonite clay of the Berezovsky deposit, and zeolite of the Kholinsky deposit can be used as components of the permeable barrier. Biofouling of natural loams from a contaminated aquifer can also occur under favorable conditions. It has been suggested that the anammox activity is determined by a number of factors, including the presence of the essential trace elements in the carrier and the surface morphology. However, one of the most important factors is competition with other microbial groups that can develop on the surface of the carrier at a faster rate. For this reason, carriers with a high specific surface area and containing the necessary microelements were overgrown with the most rapidly growing microorganisms. Bioaugmentation with a "warm" anammox community from a laboratory reactor dominated by Ca. Kuenenia improved nitrogen removal rates and biofilm formation on most of the mineral carriers, including bentonite clay of the Dinozavrovoye deposit, as well as loamy rock and zeolite-containing tripoli, in addition to carriers that perform best with the indigenous anammox community. The feasibility of coupled partial denitrification-anammox and the adaptation of a "warm" anammox community to low temperatures and hazardous components contained in polluted groundwater prior to bioaugmentation should be the scope of future research to enhance the anammox process in cold, nitrate-rich aquifers.}, } @article {pmid36290085, year = {2022}, author = {Zheng, M and Zhu, K and Peng, H and Shang, W and Zhao, Y and Lu, S and Rao, X and Li, M and Zhou, R and Li, G}, title = {CcpA Regulates Staphylococcus aureus Biofilm Formation through Direct Repression of Staphylokinase Expression.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290085}, issn = {2079-6382}, support = {31900145//National Natural Science Foundation of China/ ; 2019JCLC02//Science Foundation of the Army Medical University/ ; }, abstract = {Staphylococcus aureus represents a notorious opportunistic pathogen causing various infections in biofilm nature, imposing remarkable therapeutic challenges worldwide. The catabolite control protein A (CcpA), a major regulator of carbon catabolite repression (CCR), has been recognized to modulate S. aureus biofilm formation, while the underlying mechanism remains to be fully elucidated. In this study, the reduced biofilm was firstly determined in the ccpA deletion mutant of S. aureus clinical isolate XN108 using both crystal violet staining and confocal laser scanning microscopy. RNA-seq analysis suggested that sak-encoding staphylokinase (Sak) was significantly upregulated in the mutant ∆ccpA, which was further confirmed by RT-qPCR. Consistently, the induced Sak production correlated the elevated promoter activity of sak and increased secretion in the supernatants, as demonstrated by Psak-lacZ reporter fusion expression and chromogenic detection, respectively. Notably, electrophoretic mobility shift assays showed that purified recombinant protein CcpA binds directly to the promoter region of sak, suggesting the direct negative control of sak expression by CcpA. Double isogenic deletion of ccpA and sak restored biofilm formation for mutant ∆ccpA, which could be diminished by trans-complemented sak. Furthermore, the exogenous addition of recombinant Sak inhibited biofilm formation for XN108 in a dose-dependent manner. Together, this study delineates a novel model of CcpA-controlled S. aureus biofilm through direct inhibition of sak expression, highlighting the multifaceted roles and multiple networks regulated by CcpA.}, } @article {pmid36290078, year = {2022}, author = {Früh, R and Anderson, A and Cieplik, F and Hellwig, E and Wittmer, A and Vach, K and Al-Ahmad, A}, title = {Antibiotic Resistance of Selected Bacteria after Treatment of the Supragingival Biofilm with Subinhibitory Chlorhexidine Concentrations.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290078}, issn = {2079-6382}, support = {AL 1179/4-1//Deutsche Forschungsgemeinschaft/ ; CI 263/3-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Due to increasing rates of antibiotic resistance and very few novel developments of antibiotics, it is crucial to understand the mechanisms of resistance development. The aim of the present study was to investigate the adaptation of oral bacteria to the frequently used oral antiseptic chlorhexidine digluconate (CHX) and potential cross-adaptation to antibiotics after repeated exposure of supragingival plaque samples to subinhibitory concentrations of CHX. Plaque samples from six healthy donors were passaged for 10 days in subinhibitory concentrations of CHX, while passaging of plaque samples without CHX served as control. The surviving bacteria were cultured on agar plates and identified with Matrix-assisted Laser Desorption/Ionization-Time of Flight-Mass spectrometry (MALDI-TOF). Subsequently, the minimum inhibitory concentrations (MIC) of these isolates toward CHX were determined using a broth-microdilution method, and phenotypic antibiotic resistance was evaluated using the epsilometertest. Furthermore, biofilm-forming capacities were determined. Repeated exposure of supragingival plaque samples to subinhibitory concentrations of CHX led to the selection of oral bacteria with 2-fold up to 4-fold increased MICs toward CHX. Furthermore, these isolates showed up to 12-fold increased MICs towards some antibiotics such as erythromycin and clindamycin. Conversely, biofilm-forming capacity was decreased. In summary, this study shows that oral bacteria are able to adapt to CHX, while also decreasing their susceptibility to antibiotics.}, } @article {pmid36290070, year = {2022}, author = {Haasbroek, K and Yagi, M and Yonei, Y}, title = {Staphylococcus aureus Biofilm Inhibiting Activity of Advanced Glycation Endproduct Crosslink Breaking and Glycation Inhibiting Compounds.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290070}, issn = {2079-6382}, abstract = {Staphylococcus aureus is a Gram-positive bacterium that plays a role in the pathogenesis of skin lesions in diabetes mellitus, atopic dermatitis, and psoriasis, all of which are associated with elevated non-enzymatic glycation biomarkers. The production of biofilm protects resident bacteria from host immune defenses and antibiotic interventions, prolonging pathogen survival, and risking recurrence after treatment. Glycated proteins formed from keratin and glucose induce biofilm formation in S. aureus, promoting dysbiosis and increasing pathogenicity. In this study, several glycation-inhibiting and advanced glycation endproduct (AGE) crosslink-breaking compounds were assayed for their ability to inhibit glycated keratin-induced biofilm formation as preliminary screening for clinical testing candidates. Ascorbic acid, astaxanthin, clove extract, n-phenacylthiazolium bromide, and rosemary extract were examined in an in vitro static biofilm model with S. aureus strain ATCC 12600. Near complete biofilm inhibition was achieved with astaxanthin (ED50 = 0.060 mg/mL), clove extract (ED50 = 0.0087 mg/mL), n-phenacylthiazolium bromide (ED50 = 5.3 mg/mL), and rosemary extract (ED50 = 1.5 mg/mL). The dosage necessary for biofilm inhibition was not significantly correlated with growth inhibition (R[2] = 0.055. p = 0.49). Anti-glycation and AGE breaking compounds with biofilm inhibitory activity are ideal candidates for treatment of S. aureus dysbiosis and skin infection that is associated with elevated skin glycation.}, } @article {pmid36290061, year = {2022}, author = {Xu, J and Lin, Q and Sheng, M and Ding, T and Li, B and Gao, Y and Tan, Y}, title = {Antibiofilm Effect of Cinnamaldehyde-Chitosan Nanoparticles against the Biofilm of Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290061}, issn = {2079-6382}, abstract = {Food contamination caused by food-spoilage bacteria and pathogenic bacteria seriously affects public health. Staphylococcus aureus is a typical foodborne pathogen which easily forms biofilm. Once biofilm is formed, it is difficult to remove. The use of nanotechnology for antibiofilm purposes is becoming more widespread because of its ability to increase the bioavailability and biosorption of many drugs. In this work, chitosan nanoparticles (CSNPs) were prepared by the ion-gel method with polyanionic sodium triphosphate (TPP). Cinnamaldehyde (CA) was loaded onto the CSNPs. The particle size, potential, morphology, encapsulation efficiency and in vitro release behavior of cinnamaldehyde-chitosan nanoparticles (CSNP-CAs) were studied, and the activity of CA against S. aureus biofilms was evaluated. The biofilm structure on the silicone surface was investigated by scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) was used to detect live/dead organisms within biofilms. The results showed that CSNP-CAs were dispersed in a circle with an average diameter of 298.1 nm and a zeta potential of +38.73 mV. The encapsulation efficiency of cinnamaldehyde (CA) reached 39.7%. In vitro release studies have shown that CA can be continuously released from the CSNPs. Compared with free drugs, CSNP-CAs have a higher efficacy in removing S. aureus biofilm, and the eradication rate of biofilm can reach 61%. The antibiofilm effects of CSNP-CAs are determined by their antibacterial properties. The minimum inhibitory concentration (MIC) of CA is 1.25 mg/mL; at this concentration the bacterial cell wall ruptures and the permeability of the cell membrane increases, which leads to leakage of the contents. At the same time, we verified that the MIC of CSNP-CAs is 2.5 mg/mL (drug concentration). The synergy between CA and CSNPs demonstrates the combinatorial application of a composite as an efficient novel therapeutic agent against antibiofilm. We can apply it in food preservation and other contexts, providing new ideas for food preservation.}, } @article {pmid36290054, year = {2022}, author = {Kukushkina, EA and Mateos, H and Altun, N and Sportelli, MC and Gonzalez, P and Picca, RA and Cioffi, N}, title = {Highly Stable Core-Shell Nanocolloids: Synergy between Nano-Silver and Natural Polymers to Prevent Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290054}, issn = {2079-6382}, support = {813439//European Union/ ; }, abstract = {Active investment in research time in the development and study of novel unconventional antimicrobials is trending for several reasons. First, it is one of the ways which might help to fight antimicrobial resistance and bacterial contamination due to uncontrolled biofilm growth. Second, minimizing harmful environmental outcomes due to the overuse of toxic chemicals is one of the highest priorities nowadays. We propose the application of two common natural compounds, chitosan and tannic acid, for the creation of a highly crosslinked polymer blend with not only intrinsic antimicrobial properties but also reducing and stabilizing powers. Thus, the fast and green synthesis of fine spherically shaped Ag nanoparticles and further study of the composition and properties of the colloids took place. A positively charged core-shell nanocomposition, with an average size in terms of the metal core of 17 ± 4 nm, was developed. Nanoantimicrobials were characterized by several spectroscopic (UV-vis and FTIR) and microscopic (transmission and scanning electron microscopies) techniques. The use of AgNPs as a core and an organic polymer blend as a shell potentially enable a synergistic long-lasting antipathogen effect. The antibiofilm potential was studied against the food-borne pathogens Salmonella enterica and Listeria monocytogenes. The antibiofilm protocol efficiency was evaluated by performing crystal violet assay and optical density measurements, direct visualization by confocal laser scanning microscopy and morphological studies by SEM. It was found that the complex nanocomposite has the ability to prevent the growth of biofilm. Further investigation for the potential application of this stable composition in food packaging will be carried out.}, } @article {pmid36290033, year = {2022}, author = {Carradori, S and Ammazzalorso, A and De Filippis, B and Şahin, AF and Akdemir, A and Orekhova, A and Bonincontro, G and Simonetti, G}, title = {Azole-Based Compounds That Are Active against Candida Biofilm: In Vitro, In Vivo and In Silico Studies.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36290033}, issn = {2079-6382}, abstract = {Fungal pathogens, including Candida spp., Aspergillus spp. and dermatophytes, cause more than a billion human infections every year. A large library of imidazole- and triazole-based compounds were in vitro screened for their antifungal activity against C. albicans, C. glabrata, C. krusei, A. fumigatus and dermatophytes, such as Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes. The imidazole carbamate 12 emerged as the most active compound, showing a valuable antifungal activity against C. glabrata (MIC 1−16 μg/mL) and C. krusei (MIC 4−24 μg/mL). No activity against A. fumigatus or the dermatophytes was observed among all the tested compounds. The compound 12 inhibited the formation of C. albicans, C. glabrata and C. krusei biofilms and reduced the mature Candida biofilm. In the Galleria mellonella larvae, 12 showed a significant reduction in the Candida infection, together with a lack of toxicity at the concentration used to activate its antifungal activity. Moreover, the in silico prediction of the putative targets revealed that the concurrent presence of the imidazole core, the carbamate and the p-chlorophenyl is important for providing a strong affinity for lanosterol 14α-demethylase (CgCYP51a1) and the fungal carbonic anhydrase (CgNce103), the S-enantiomer being more productive in these interactions.}, } @article {pmid36289997, year = {2022}, author = {Andrade, M and Oliveira, K and Morais, C and Abrantes, P and Pomba, C and Rosato, AE and Couto, I and Costa, SS}, title = {Virulence Potential of Biofilm-Producing Staphylococcus pseudintermedius, Staphylococcus aureus and Staphylococcus coagulans Causing Skin Infections in Companion Animals.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36289997}, issn = {2079-6382}, support = {UID/04413/2020//Fundação para a Ciência e Tecnologia/ ; UI/BD/151061/2021//Fundação para a Ciência e Tecnologia/ ; UID/CVT/00276/2020//Fundação para a Ciência e Tecnologia/ ; LISBOA-01-0145-FEDER-030713, PTDC/CAL-EST/30713/2017//FEDER - Fundo Europeu para o Desenvolvimento Regional/ FCT/ ; }, abstract = {Coagulase-positive staphylococci (CoPS) account for most bacteria-related pyoderma in companion animals. Emergence of methicillin-resistant strains of Staphylococcus pseudintermedius (MRSP), Staphylococcus aureus (MRSA) or Staphylococcus coagulans (MRSC), often with multidrug-resistant (MDR) phenotypes, is a public health concern. The study collection comprised 237 staphylococci (S. pseudintermedius (n = 155), S. aureus (n = 55) and S. coagulans (n = 27)) collected from companion animals, previously characterized regarding resistance patterns and clonal lineages. Biofilm production was detected for 51.0% (79/155), 94.6% (52/55) and 88.9% (24/27) of the S. pseudintermedius, S. aureus and S. coagulans, respectively, and was a frequent trait of the predominant S. pseudintermedius and S. aureus clonal lineages. The production of biofilm varied with NaCl supplementation of the growth media. All S. pseudintermedius and S. aureus strains carried icaADB. Kaplan-Meier survival analysis of Galleria mellonella infected with different CoPS revealed a higher virulence potential of S. aureus when compared with other CoPS. Our study highlights a high frequency of biofilm production by prevalent antimicrobial-resistant clonal lineages of CoPS associated with animal pyoderma, potentially related with a higher virulence potential and persistent or recurrent infections.}, } @article {pmid36289958, year = {2022}, author = {Sánchez-Somolinos, M and Díaz-Navarro, M and Benjumea, A and Tormo, M and Matas, J and Vaquero, J and Muñoz, P and Sanz-Ruíz, P and Guembe, M}, title = {Determination of the Elution Capacity of Dalbavancin in Bone Cements: New Alternative for the Treatment of Biofilm-Related Peri-Prosthetic Joint Infections Based on an In Vitro Study.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36289958}, issn = {2079-6382}, support = {MSII/00008//Instituto de Salud Carlos III/ ; PI21/00344//Instituto de Salud Carlos III/ ; PEJD-2020-AI_BMD-17971//Consejería de Educación, Juventud y Deporte/ ; FMM21/01//Fundación Mutua Madrileña/ ; }, abstract = {Antibiotic-loaded bone cement is the most widely used approach for the treatment of biofilm-induced septic sequelae in orthopedic surgery. Dalbavancin is a lipoglycopeptide that acts against Gram-positive bacteria and has a long half-life, so we aimed to assess whether it could be a new alternative drug in antibiotic-loaded bone cement for the treatment of periprosthetic joint infections. We assessed the elution capacity of dalbavancin and compared it with that of vancomycin in bone cement. Palacos[®]R (Heraeus Medical GmbH, Wehrheim, Germany) bone cement was manually mixed with each of the antibiotics studied at 2.5% and 5%. Three cylinders were obtained from each of the mixtures; these were weighed and incubated in 5 mL phosphate-buffered saline at 37°C under shaking for 1 h, 2 h, 4 h, 8 h, 24 h, 48 h, 168 h, and 336 h. PBS was replenished at each time point. The samples were analyzed using high-performance liquid chromatography (vancomycin) and mass cytometry (dalbavancin). Elution was higher than the minimum inhibitory concentration (MIC)90 for both antibiotics after 14 days of study. The release of vancomycin at 14 days was higher than of dalbavancin at each concentration tested (p = 0.05, both). However, the cumulative release of 5% dalbavancin was similar to that of 2.5% vancomycin (p = 0.513). The elution capacity of dalbavancin reached a cumulative concentration similar to that of vancomycin. Moreover, considering that the MIC90 of dalbavancin is one third that of vancomycin (0.06 mg/L and 2 mg/L, respectively) and given the long half-life of dalbavancin, it may be a new alternative for the treatment of biofilm-related periprosthetic infections when loaded in bone cement.}, } @article {pmid36289954, year = {2022}, author = {Zúñiga, I and Iniesta, M and Virto, L and Ribeiro-Vidal, H and Alonso-Español, A and Hernández, F and Cardona, JJ and Maher-Lavandero, A and Alonso, B and Sanz, M and Herrera, D}, title = {Dental Biofilm Removal and Bacterial Contamination of a New Doubled-Side Thermoplastic Polyurethane-Based Toothbrush: A Crossover Study in Healthy Volunteers.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36289954}, issn = {2079-6382}, support = {233-2021//Ziz Dental Care SL/ ; }, abstract = {Multiple toothbrush designs have been developed to enhance dental biofilm removal and decrease bacterial contamination and retention over time. Therefore, the aim of this clinical study was to compare the efficacy of a prototype of a new double-sided thermoplastic polyurethane-based toothbrush with that of a conventional nylon-bristle toothbrush. A crossover study was conducted in systemically healthy volunteers (n = 24) for two one-week periods plus one washout week. As outcome variables, plaque and gingival indices, total bacterial contamination of the toothbrushes by quantitative polymerase chain reaction (qPCR), and patient-reported outcomes were measured. Clinical and microbiological variables were analysed using a general linear model and Friedman and Wilcoxon signed-rank tests. No statistically significant differences between toothbrushes were detected neither for full-mouth PlI (p > 0.05) nor for GI (p > 0.05). Similarly, no statistically significant differences were detected for bacterial contamination after 40 seconds or 1 week of use, with results expressed either in CFU/mL or in CFU/mm2 (p > 0.05). In conclusion, the tested prototype toothbrush was as effective and safe as the control toothbrush, and the participating subjects did not experience any adverse effects from its use and rated its efficiency and effectiveness in cleaning their teeth as satisfactory.}, } @article {pmid36289936, year = {2022}, author = {Yee, R and Yuan, Y and Tarff, A and Brayton, C and Gour, N and Feng, J and Zhang, Y}, title = {Eradication of Staphylococcus aureus Biofilm Infection by Persister Drug Combination.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {36289936}, issn = {2079-6382}, abstract = {Staphylococcus aureus can cause a variety of infections, including persistent biofilm infections, which are difficult to eradicate with current antibiotic treatments. Here, we demonstrate that combining drugs that have robust anti-persister activity, such as clinafloxacin or oritavancin, in combination with drugs that have high activity against growing bacteria, such as vancomycin or meropenem, could completely eradicate S. aureus biofilm bacteria in vitro. In contrast, single or two drugs, including the current treatment doxycycline plus rifampin for persistent S. aureus infection, failed to kill all biofilm bacteria in vitro. In a chronic persistent skin infection mouse model, we showed that the drug combination clinafloxacin + meropenem + daptomycin which killed all biofilm bacteria in vitro completely eradicated S. aureus biofilm infection in mice while the current treatments failed to do so. The complete eradication of biofilm bacteria is attributed to the unique high anti-persister activity of clinafloxacin, which could not be replaced by other fluoroquinolones including moxifloxacin, levofloxacin, or ciprofloxacin. We also compared our persister drug combination with the current approaches for treating persistent infections, including gentamicin + fructose and ADEP4 + rifampin in the S. aureus biofilm infection mouse model, and found neither treatment could eradicate the biofilm infection. Our study demonstrates an important treatment principle, the Yin-Yang model, for persistent infections by targeting both growing and non-growing heterogeneous bacterial populations, utilizing persister drugs for the more effective eradication of persistent and biofilm infections. Our findings have implications for the improved treatment of other persistent and biofilm infections in general.}, } @article {pmid36289389, year = {2022}, author = {Riester, O and Burkhardtsmaier, P and Gurung, Y and Laufer, S and Deigner, HP and Schmidt, MS}, title = {Synergy of R-(-)carvone and cyclohexenone-based carbasugar precursors with antibiotics to enhance antibiotic potency and inhibit biofilm formation.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {18019}, pmid = {36289389}, issn = {2045-2322}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Carbasugars/pharmacology ; Microbial Sensitivity Tests ; Escherichia coli ; Biofilms ; Penicillins/pharmacology ; Streptomycin/pharmacology ; }, abstract = {The widespread use of antibiotics in recent decades has been a major factor in the emergence of antibiotic resistances. Antibiotic-resistant pathogens pose increasing challenges to healthcare systems in both developing and developed countries. To counteract this, the development of new antibiotics or adjuvants to combat existing resistance to antibiotics is crucial. Glycomimetics, for example carbasugars, offer high potential as adjuvants, as they can inhibit metabolic pathways or biofilm formation due to their similarity to natural substrates. Here, we demonstrate the synthesis of carbasugar precursors (CSPs) and their application as biofilm inhibitors for E. coli and MRSA, as well as their synergistic effect in combination with antibiotics to circumvent biofilm-induced antibiotic resistances. This results in a biofilm reduction of up to 70% for the CSP rac-7 and a reduction in bacterial viability of MRSA by approximately 45% when combined with the otherwise ineffective antibiotic mixture of penicillin and streptomycin.}, } @article {pmid36289108, year = {2022}, author = {Adeli-Sardou, M and Shakibaie, M and Forootanfar, H and Jabari-Morouei, F and Riahi-Madvar, S and Ghafari-Shahrbabaki, SS and Mehrabani, M}, title = {Cytotoxicity and anti-biofilm activities of biogenic cadmium nanoparticles and cadmium nitrate: a preliminary study.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {12}, pages = {246}, pmid = {36289108}, issn = {1573-0972}, support = {400000795//Pharmaceutical Sciences and Cosmetic Products Research Center, Kerman University of Medical Sciences (Kerman, Iran)./ ; }, mesh = {Cadmium/toxicity ; Vancomycin/pharmacology ; Staphylococcus aureus ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Meropenem/pharmacology ; Biofilms ; Pseudomonas aeruginosa ; Anti-Bacterial Agents/pharmacology ; *Nanoparticles ; *Anti-Infective Agents/pharmacology ; Gentamicins/pharmacology ; Kanamycin/pharmacology ; Streptomycin/pharmacology ; Tetracyclines/pharmacology ; *Metal Nanoparticles ; }, abstract = {Wild-type microorganisms have become tolerant to higher antibiotic and antimicrobial agent concentrations due to the global increase in antibiotic consumption. Green-synthesized nanoparticles (NPs) have been proposed as potential antimicrobial agents to overcome the problem. This research prepared cadmium nanoparticles (Cd NPs) using Artemisia persica extract. To clarify the biological behavior of Cd NPs and Cd (NO3)2, cytotoxicity, antibacterial, anti-biofilm, and biocompatible experiments were performed. Since Cd toxicity is associated with liver, kidney damage, and other deficits, HepG2 and HUVEC cell lines were employed as the in vitro cytotoxicity models. Cd NPs had a lower cytotoxic effect than Cd (NO3)2 against both HepG2 and HUVEC cells. The Cd NPs exhibited no hemolysis activity. The antibacterial and anti-biofilm studies were conducted using gram-positive Staphylococcus aureus and gram-negative Proteus mirabilis and Pseudomonas aeruginosa with the ability to form severe adherent biofilms. The antibacterial activity of Cd NPs against clinically isolated S. aureus, P. mirabilis, and P. aeruginosa was above 2560 µg mL[- 1]. The Cd NPs (640 µg mL[- 1]) decreased the biofilm formation of S. aureus, P. mirabilis, and P. aeruginosa by 24.6%, 31.6%, and 26.4%, respectively.Moreover, adding Cd NPs (100 µg/disc) to antibiotic discs increased the antibacterial activity of vancomycin, gentamicin, tetracycline, streptomycin, meropenem, and kanamycin against Methicillin-resistant S. aureus, significantly. Due to the emergence of resistant microorganisms, Cd NPs can be used as an exciting material to counterattack global health problems. Further research is needed to clarify the molecular mechanisms underlying Cd NPs' pharmacological and toxicological effects.}, } @article {pmid36288959, year = {2022}, author = {Putra Wigianto, AY and Ishida, Y and Iwawaki, Y and Goto, T and Watanabe, M and Sekine, K and Hamada, K and Murakami, K and Fujii, H and Ichikawa, T}, title = {2-methacryloyloxyethyl phosphorylcholine polymer treatment prevents Candida albicans biofilm formation on acrylic resin.}, journal = {Journal of prosthodontic research}, volume = {}, number = {}, pages = {}, doi = {10.2186/jpr.JPR_D_22_00102}, pmid = {36288959}, issn = {2212-4632}, abstract = {PURPOSE: We aimed to evaluate the effectiveness of photoreactive 2-methacryloyloxyethyl phosphorylcholine (MPC) in inhibiting Candida albicans biofilm formation on polymethyl methacrylate (PMMA) and assess its mechanism and need for re-application by evaluating its interaction with salivary mucin and durability during temperature changes.

METHODS: PMMA discs were used as specimens. The MPC coating was applied using the spray and cure technique for the treatment groups, whereas no coating was applied to the control. The MPC treatment (MT) groups were further differentiated based on the number of thermal cycles involved (0, 1000, 2500, and 5000). The optical density was measured to assess mucin adsorption (MA). Contact angle (CA) was calculated to evaluate surface hydrophilicity. The presence of MPC components on the PMMA surface was assessed using X-ray photoelectron spectroscopy (XPS). C. albicans biofilms were evaluated qualitatively (scanning electron microscope images) and quantitatively (colony-forming units (CFUs)). Statistical analysis was conducted using two-way analysis of variance and Tukey's multiple comparison test.

RESULTS: MA rate and CA increased significantly in the MT groups, which exhibited significantly fewer CFUs and thinner biofilms than those of the control group. Based on the XPS, MA, and CFU evaluations, the durability and efficacy of the MPC coating were considered stable up to 2500 thermal cycles. Additionally, a significant interaction was observed between mucin concentration and MPC efficacy.

CONCLUSIONS: The photoreactive MPC coating, which was resistant to temperature changes for approximately 3 months, effectively prevented C. albicans biofilm formation by modifying surface hydrophilicity and increasing mucin adsorption.}, } @article {pmid36288773, year = {2022}, author = {Li, J and Wang, H and Li, N and Zhang, Y and Lü, X and Liu, B}, title = {Antibiotic susceptibility and biofilm-forming ability of Veillonella strains.}, journal = {Anaerobe}, volume = {78}, number = {}, pages = {102667}, doi = {10.1016/j.anaerobe.2022.102667}, pmid = {36288773}, issn = {1095-8274}, mesh = {Humans ; *Veillonella ; *Vancomycin/pharmacology ; Cefoxitin ; Clindamycin/pharmacology ; Moxifloxacin ; Metronidazole ; Biofilms ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology ; Ampicillin/pharmacology ; Tetracyclines ; Piperacillin ; Tazobactam ; }, abstract = {INTRODUCTION: Veillonella, known as early colonizers in oral biofilms, take part in some infections in human. Biofilm refers to complex, sessile communities of microbes, which function as strong barriers for bacteria to survive. Biofilm matrixes surrounding bacteria enable them to withstand harsh conditions, protect against immune cells, etc., and also make them resistant to antimicrobial treatments. Thus, the knowledge of antibiotic susceptibility and biofilm formation of Veillonella will shed light on their resistance mechanism.

MATERIALS AND METHOD: Their morphology was observed by scanning electron microscopy (SEM). According to the performance standards for antibiotic susceptibility testing of the Clinical & Laboratory Standards Institute, the Agar dilution method was used to study the susceptibility of Veillonella strains to eight antibiotics (ampicillin, piperacillin-tazobactam, cefoxitin, tetracycline, moxifloxacin, clindamycin, metronidazole, and vancomycin). In addition, we applied the crystal violet staining method to reveal the processes of biofilm formation of these Veillonella strains.

RESULTS: V. rogosae, V. nakazawae, and V. parvula were isolated from oral cavities of healthy adults and V. ratti was isolated from dairy goat droppings. Observations by scanning electron microscopy showed that Veillonella were spherical and arranged in single or short chains. The diameter of a single cell was about 0.3-0.5 μm. The Minimum Inhibitory Concentrations (MICs) of the antibiotics were determined and the results showed that these four strains were all sensitive to cefoxitin, tetracycline, moxifloxacin, clindamycin and metronidazole. Among the four strains, V. ratti was resistant to piperacillin-tazobactam, and V. rogosae and V. nakazawae were resistant to ampicillin. The vancomycin susceptibility of the four Veillonella strains varied greatly. The MICs of vancomycin against V. rogosae and V. ratti were greater than 256 μg/mL but the MICs of vancomycin against V. nakazawae and V. parvula were less than 2 μg/mL. V. parvula had significantly higher biofilm-forming ability than the other three strains (p < 0.05) and V. nakazawae had the weakest biofilm-forming ability.

CONCLUSION: In this study, V. rogosae, V. nakazawae, V. parvula and V. ratti were isolated and identified. The four strains of Veillonella showed differences in MIC values for different antibiotics and biofilm-forming ability.}, } @article {pmid36288628, year = {2023}, author = {Xiang, Z and Chen, X and Bai, J and Li, B and Li, H and Huang, X}, title = {Bioaugmentation performance for moving bed biofilm reactor (MBBR) treating mariculture wastewater by an isolated novel halophilic heterotrophic nitrification aerobic denitrification (HNAD) strain (Zobellella B307).}, journal = {Journal of environmental management}, volume = {325}, number = {Pt B}, pages = {116566}, doi = {10.1016/j.jenvman.2022.116566}, pmid = {36288628}, issn = {1095-8630}, mesh = {*Nitrification ; *Wastewater/chemistry ; Denitrification ; Biofilms ; Bioreactors/microbiology ; Heterotrophic Processes ; Nitrogen/metabolism ; }, abstract = {Moving bed biofilm reactor (MBBR) demonstrates weak nitrogen removal for mariculture wastewater treatment under high salinity environment. An isolated novel halophilic heterotrophic nitrification aerobic denitrification (HNAD) strain (Zobellella B307) was applied in MBBR process to enhance nitrogen removal. Results showed that strain Zobellella B307 could remove 90.9% ammonia nitrogen (NH4[+]-N) and 97.1% nitrate nitrogen (NO3[-]-N) after 10 h cultivation, and strong resistance to salinity variation (high growth and nitrogen removal efficiency with salinity of 65‰) was observed. Besides, the chemical oxygen demand (COD), NH4[+]-N and NO3[-]-N removal reached 95.6%, 94.4% and 85.7% with the strain added into MBBR process. In addition, microbial community structure analysis reflected that the strain Zobellella B307 successfully proliferated (the relative abundance increased to 2.33%). The HNAD bacteria abundance increased and dominated during the nitrogen removal process with the strain inoculation. A microbial functional analysis revealed that the main dominant functional categories (carbohydrate metabolism and amino acid metabolism) increased with the bioaugmentation of strain Zobellella B307, thus improving the nitrogen removal.}, } @article {pmid36288477, year = {2022}, author = {Kuper, TJ and Wang, LZ and Prud'homme, RK and Datta, SS and Ford, RM}, title = {Chemorepellent-Loaded Nanocarriers Promote Localized Interference of Escherichia coli Transport to Inhibit Biofilm Formation.}, journal = {ACS applied bio materials}, volume = {5}, number = {11}, pages = {5310-5320}, doi = {10.1021/acsabm.2c00712}, pmid = {36288477}, issn = {2576-6422}, support = {T32 GM136615/GM/NIGMS NIH HHS/United States ; }, mesh = {*Escherichia coli ; *Nickel/pharmacology ; Biofilms ; Polymers/pharmacology ; }, abstract = {To mitigate antimicrobial resistance, we developed polymeric nanocarrier delivery of the chemorepellent signaling agent, nickel, to interfere with Escherichia coli transport to a surface, an incipient biofilm formation stage. The dynamics of nickel nanocarrier (Ni NC) chemorepellent release and induced chemorepellent response required to effectively modulate bacterial transport for biofilm prevention were characterized in this work. Ni NCs were fabricated with the established Flash NanoPrecipitation method. NC size was characterized with dynamic light scattering. Measured with a zincon monosodium salt colorimetric assay, NC nickel release was pH-dependent, with 62.5% of total encapsulated nickel released at pH 7 within 0-15 min, competitive with rapid E. coli transport to the surface. Confocal laser scanning microscopy of E. coli (GFP-expressing) biofilm growth dynamics on fluorescently labeled Ni NC coated glass coupled with a theoretical dynamical criterion probed the biofilm prevention outcomes of NC design. The Ni NC coating significantly reduced E. coli attachment compared to a soluble nickel coating and reduced E. coli biomass area by 61% compared to uncoated glass. A chemical-in-plug assay revealed Ni NCs induced a chemorepellent response in E. coli. A characteristic E. coli chemorepellent response was observed away from the Ni NC coated glass over 10 μm length scales effective to prevent incipient biofilm surface attachment. The dynamical criterion provided semiquantitative analysis of NC mechanisms to control biofilm and informed optimal chemorepellent release profiles to improve NC biofilm inhibition. This work is fundamental for dynamical informed design of biofilm-inhibiting chemorepellent-loaded NCs promising to mitigate the development of resistance and interfere with the transport of specific pathogens.}, } @article {pmid36288405, year = {2022}, author = {Jeckel, H and Díaz-Pascual, F and Skinner, DJ and Song, B and Jiménez-Siebert, E and Strenger, K and Jelli, E and Vaidya, S and Dunkel, J and Drescher, K}, title = {Shared biophysical mechanisms determine early biofilm architecture development across different bacterial species.}, journal = {PLoS biology}, volume = {20}, number = {10}, pages = {e3001846}, pmid = {36288405}, issn = {1545-7885}, support = {716734/ERC_/European Research Council/International ; }, mesh = {*Biofilms ; Pseudomonas aeruginosa/genetics ; *Vibrio cholerae/genetics ; Escherichia coli/genetics ; }, abstract = {Bacterial biofilms are among the most abundant multicellular structures on Earth and play essential roles in a wide range of ecological, medical, and industrial processes. However, general principles that govern the emergence of biofilm architecture across different species remain unknown. Here, we combine experiments, simulations, and statistical analysis to identify shared biophysical mechanisms that determine early biofilm architecture development at the single-cell level, for the species Vibrio cholerae, Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa grown as microcolonies in flow chambers. Our data-driven analysis reveals that despite the many molecular differences between these species, the biofilm architecture differences can be described by only 2 control parameters: cellular aspect ratio and cell density. Further experiments using single-species mutants for which the cell aspect ratio and the cell density are systematically varied, and mechanistic simulations show that tuning these 2 control parameters reproduces biofilm architectures of different species. Altogether, our results show that biofilm microcolony architecture is determined by mechanical cell-cell interactions, which are conserved across different species.}, } @article {pmid36288093, year = {2022}, author = {Chen, J and Chen, J and Wang, Z and Chen, C and Zheng, J and Yu, Z and Deng, Q and Zhao, Y and Wen, Z}, title = {20S-ginsenoside Rg3 inhibits the biofilm formation and haemolytic activity of Staphylococcus aureus by inhibiting the SaeR/SaeS two-component system.}, journal = {Journal of medical microbiology}, volume = {71}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001587}, pmid = {36288093}, issn = {1473-5644}, mesh = {Humans ; Staphylococcus aureus/genetics ; Leukocidins ; Gentian Violet/metabolism ; Proteome/metabolism ; Bacterial Proteins/genetics/metabolism ; Transcription Factors/genetics ; *Staphylococcal Infections ; Virulence Factors/genetics/metabolism ; Biofilms ; Anti-Bacterial Agents/pharmacology/metabolism ; Fibrinogen/metabolism ; *Biological Products ; Immunoglobulins/metabolism ; }, abstract = {Introduction. Staphylococcus aureus is a major cause of chronic diseases and biofilm formation is a contributing factor. 20S-ginsenoside Rg3 (Rg3) is a natural product extracted from the traditional Chinese medicine red ginseng.Gap statement. The effects of Rg3 on biofilm formation and haemolytic activity as well as its antibacterial mechanism against S. aureus have not been reported.Aim. This study aimed to investigate the effects of Rg3 on biofilm formation and haemolytic activity as well as its antibacterial action against clinical S. aureus isolates.Methodology. The effect of Rg3 on biofilm formation of clinical S. aureus isolates was studied by crystal violet staining. Haemolytic activity analysis was carried out. Furthermore, the influence of Rg3 on the proteome profile of S. aureus was studied by quantitative proteomics to clarify the mechanism underlying its antibacterial action and further verified by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR).Results. Rg3 significantly inhibited biofilm formation and haemolytic activity in clinical S. aureus isolates. A total of 63 with >1.5-fold changes in expression were identified, including 34 upregulated proteins and 29 downregulated proteins. Based on bioinformatics analysis, the expression of several virulence factors and biofilm-related proteins, containing CopZ, CspA, SasG, SaeR/SaeS two-component system and SaeR/SaeS-regulated proteins, including leukocidin-like protein 2, immunoglobulin-binding protein G (Sbi) and fibrinogen-binding protein, in the S. aureus of the Rg3-treated group was downregulated. RT-qPCR confirmed that Rg3 inhibited the regulation of SaeR/SaeS and decreased the transcriptional levels of the biofilm-related genes CopZ, CspA and SasG.Conclusions. Rg3 reduces the formation of biofilm by reducing cell adhesion and aggregation. Further, Rg3 can inhibit the SaeR/SaeS two-component system, which acts as a crucial signal transduction system for the anti-virulence activity of Rg3 against clinical S. aureus isolates.}, } @article {pmid36288091, year = {2022}, author = {Zhou, R and Li, S}, title = {Dilemma and a way out for bacterial biofilm research.}, journal = {Journal of medical microbiology}, volume = {71}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001586}, pmid = {36288091}, issn = {1473-5644}, mesh = {Animals ; *Biofilms ; Bacteria/genetics ; Anti-Bacterial Agents ; *Bacterial Infections/microbiology ; }, abstract = {Biofilm-associated infections (BAIs) are more common in clinical practice and have become a public health problem of global concern. We present our views on current research (detection methods, mechanism research, animal model construction, treatment strategies, etc.) on biofilms and BAIs, and discuss future developments concerning this important issue.}, } @article {pmid36284946, year = {2022}, author = {Kadhim Mohammed, R}, title = {Investigation of the Role of Virulence Gene in Biofilm Formation of Escherichia coli Obtained from Clinical Specimens in Baghdad.}, journal = {Archives of Razi Institute}, volume = {77}, number = {2}, pages = {915-921}, pmid = {36284946}, issn = {2008-9872}, mesh = {Female ; Male ; Agar ; Anti-Bacterial Agents ; Biofilms ; Escherichia coli/genetics ; *Escherichia coli Infections/epidemiology ; Heat-Shock Proteins ; *Urinary Tract Infections/drug therapy/epidemiology ; Virulence/genetics ; Humans ; Child ; Adolescent ; Young Adult ; Adult ; }, abstract = {Several strains of Escherichia coli (E. coli) cause many diseases, including gastrointestinal illness, urinary tract infections, pericarditis, and septicemia. The present study aimed to evaluate the prevalence of the Universal Stress Protein (USP) virulence gene and the level of antibiotic resistance patterns associated with biofilm formation of E. coli in patients with infected burns, wounds, and urinary tract infections. Cases were selected from two hospitals of Al-Yarmouk Educational Hospitals and Baghdad Medical City, Baghdad, Iraq. The clinical specimens were classified as E. coli according to CLSI. The frequency of the USP gene was determined using the PCR technique. The rate of biofilm formation and antibiotic resistance were determined using microplate and agar diffusion methods, respectively. The recorded data on the distribution of E. coli isolates indicated that 33 (66%) of isolates were recovered from females and 17 (34%) of them were obtained from males (P=0.02). The results of the distribution of the isolates indicated that 16 (32%) and 18 (36%) isolates were recovered from 10-20 and 21-30 and 31-40 years old participants, respectively. The recorded data revealed that the highest rate of E. coli isolates was obtained from urine samples while the lowest one was recovered from burn samples (P<0.0001). The frequency of USP gene distribution from all strains was analyzed by the PCR and gel electrophoresis techniques. The results of the PCR test identified the USP gene (toxin gene) at 435 bp. The USP gene was presented in 41 (82%) E. coli isolates of all samples, including 28 isolates (46%) in women and 13 isolates (26%) in men with no significant association. Concerning the distribution due to the age groups, the USP gene was presented in 11 isolates (22%) in the age group of 10-20 years, while 14 (28%) and 16 (32%) isolates in the age groups of (21-30) and (31-40), respectively. Concerning the distribution of samples, the USP gene was presented in 1 isolate (2%) from the burn, 4 isolates (8%) from the wound, and 36 isolates (72%) from the urine. The microtiter plate method was used to evaluate biofilm formation and the results showed that 7 (14%), 28 (56%), and 15 (30%) isolates were weakly, moderately, and strongly adherent, respectively. These results filled the national gap about virulence and antimicrobial resistance of E. coli responsible for several diseases and should be used to improve the management of patients in Baghdad.}, } @article {pmid36283518, year = {2023}, author = {Wang, Y and Gao, Y and Hussain, A and Lee, HS}, title = {Optimization of biofilm conductance measurement with two-electrode microbial electrochemical cells (MECs).}, journal = {The Science of the total environment}, volume = {858}, number = {Pt 2}, pages = {159577}, doi = {10.1016/j.scitotenv.2022.159577}, pmid = {36283518}, issn = {1879-1026}, mesh = {*Biofilms ; Electrodes ; Electron Transport ; }, abstract = {This study was conducted to develop a standardized and consistent method for biofilm conductance measurement for an improved comprehension of extracellular electron transfer. Biofilm conductance (2.12 ± 0.25 × 10[-4] S) with and without a fixed anode potential did not show significant difference. The conductance showed a sigmoidal relationship with anode potential. The current-voltage profile of the tested biofilm at applied voltage larger than 100 mV showed deviation from Ohm's law. Up to 69% decrease in biofilm conductance and deviation from Ohm's law were observed in the current-voltage profile when the measurement time increased. By choosing the voltage range (0- 100 mV) and step (25 mV), measurement time (100-s at each voltage step), and anode control mode, these operation settings were found more suitable for consistent and accurate biofilm conductance measurement in the 2-Au MEC system. This represents the first study that comprehensively evaluated the environmental and instrumental parameters for biofilm conductance measurement.}, } @article {pmid36281582, year = {2022}, author = {Kamarehei, F and Mehdiabadi, M and Naderi, F}, title = {Antibacterial effects of natural compounds on biofilm formation of Streptococcus mutans.}, journal = {Clinical and experimental dental research}, volume = {8}, number = {6}, pages = {1426-1433}, pmid = {36281582}, issn = {2057-4347}, mesh = {Humans ; Streptococcus mutans ; *Dental Caries/drug therapy/microbiology ; Biofilms ; *Dental Plaque/drug therapy/microbiology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {UNLABELLED: Streptococcus mutans is the main cariogenic pathogen in the oral cavity, considered to contribute toward oral diseases. S. mutans is predominantly entrapped in plaque biofilms.

OBJECTIVES: In this study, we surveyed the antibacterial activity of natural compounds in terms of the biofilm production of S. mutans.

MATERIAL AND METHODS: We extracted the studies related to natural compounds affected on S. mutans biofilm from different databases.

RESULTS: Disruption of S. mutans viability in biofilms by a potent new pharmacological factor could inhibit and remove cavities. Various antibacterial agents are needed to destroy biofilms that remove both pathogens and commensal bacteria, and also exert inhibitory effects on many bacterial species.

CONCLUSIONS: An effective therapeutic agent for dental caries has to be capable of removing pathogens and their biofilms. Specific virulence attributes of S. mutans exist; hence, natural compounds that have excellent properties to combat such pathogens need to be selected.}, } @article {pmid36279095, year = {2022}, author = {Simoni, C and de Campos Ausani, T and Laviniki, V and Lopes, GV and de Itapema Cardoso, MR}, title = {Salmonella Derby from pig production chain over a 10-year period: antimicrobial resistance, biofilm formation, and genetic relatedness.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {4}, pages = {2185-2194}, pmid = {36279095}, issn = {1678-4405}, support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Swine ; Animals ; *Anti-Bacterial Agents/pharmacology ; *Salmonella enterica ; Colistin/pharmacology ; Polystyrenes ; Drug Resistance, Bacterial/genetics ; Meat/microbiology ; Salmonella ; Microbial Sensitivity Tests ; Tetracycline/pharmacology ; Streptomycin/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial/genetics ; }, abstract = {The aim of this study was to evaluate 140 Salmonella Derby isolates collected over a 10-year period from porcine origins (environment, pig carcass, lymph nodes, intestinal content, and pork) for their phenotypic and genotypic antimicrobial resistance, their ability to produce biofilm, and their genetic relatedness. The minimum inhibitory concentration (MIC) was determined using microdilution broth method and antimicrobial resistance genes were investigated by PCR. The quantification of biofilm formation was performed in sterile polystyrene microtiter plates. Genetic relatedness was determined by Xba-I macrorestriction analysis. The highest frequencies of non-wildtype (nWT) populations were observed against tetracycline (75.7%), streptomycin (70%), and colistin (11.4%), whereas wildtype populations were observed against ciprofloxacin, ceftazidime, and gentamicin. The resistance genes found were blaTEM (ampicillin), aadA variant (streptomycin/spectinomycin), tetA (tetracycline), and floR (florfenicol). On 96-well polystyrene microtiter plate, 68.6% of the isolates proved to be biofilm producers. Among 36 S. Derby isolates selected to PFGE analysis, 22 were clustered with 83.6% of similarity. Additionally, 27 isolates were clustered in 11 pulsotypes, which presented more than one strain with 100% of similarity. Most of S. Derby isolates were able to form biofilm and were classified as nWT or resistant to tetracycline, streptomycin, and colistin. PFGE allowed the identification of closely related S. Derby isolates that circulated in pig slaughterhouses and pork derived products along a decade.}, } @article {pmid36277626, year = {2022}, author = {Liu, WB and Gao, RT and Zhou, L and Liu, N and Chen, Z and Wu, ZQ}, title = {Combination of vancomycin and guanidinium-functionalized helical polymers for synergistic antibacterial activity and biofilm ablation.}, journal = {Chemical science}, volume = {13}, number = {35}, pages = {10375-10382}, pmid = {36277626}, issn = {2041-6520}, abstract = {The emergence of various resistant bacteria and overuse of antibiotics have led to severe side effects. Therefore, developing efficient and safe antibacterial systems is important. Herein, well-defined antimicrobial material-helical poly(phenyl guanidinium isocyanide) block copolymers with different conformations (l-P3-van, d-P3-van, and dl-P3-van) that connect vancomycin (van) to the polymer through a disulfide bond were synthesized. The prepared antimicrobial materials exhibit broad-spectrum antimicrobial activity, low bacterial resistance, and good proteolytic stability. They also overcome the intrinsic resistance of Gram-negative bacteria to van with a 100-fold increase in antimicrobial activity. Interestingly, the conformation of the material promotes its antimicrobial activity. The left-handed helix conformation shows five-fold more antimicrobial activity than the right-handed helical conformation, thereby opening a path for the application of nanochirality in the field of antibiotics.}, } @article {pmid36276899, year = {2022}, author = {Hosseini, B and Behbahani, M and Dini, G and Mohabatkar, H and Keyhanfar, M}, title = {Investigating the anti-streptococcal biofilm effect of ssDNA aptamer-silver nanoparticles complex on a titanium-based substrate.}, journal = {RSC advances}, volume = {12}, number = {38}, pages = {24876-24886}, pmid = {36276899}, issn = {2046-2069}, abstract = {Streptococcus mutans is a commensal and opportunistic pathogen that causes several diseases by forming a biofilm in humans and animals in many areas such as nasopharyngeal, cardiac valves, lungs, and oral cavity. Biofilms are very important in prosthetic infections associated with medical implants. The use of nanoparticles is one of the evolving fields in biofilm targeting. Silver nanoparticles can be used for biofilm targeting due to their inherent antimicrobial properties. Hybridization of nanoparticles with small molecules increases their biological properties and makes them multifunctional. The present investigation aimed to design an appropriate silver nanoparticles-aptamer complex that binds to the surface receptors of streptococcal strains. For this reason, silver nanoparticles with particle sizes in a range of 50 to 70 nm were synthesized and connected to a designed aptamer with a streptavidin-biotin linker. Then, the effect of the complex was investigated on the S. mutans biofilm formed on the surface of a medical-grade titanium substrate. The silver nanoparticles-aptamer complex at a concentration of 100 μg mL[-1] after 48 h inhibited 43% of the biofilm formation and degraded 63% of the formed biofilm. Also, the cell availability reached 96% and the complex was stable in cell medium culture for 360 min. It was concluded that this complex could be a good candidate for removing the formed biofilms on the surface of titanium implants.}, } @article {pmid36276550, year = {2022}, author = {Kim, S and Park, S}, title = {Chlorine dioxide gas mediated inactivation of the biofilm cells of.}, journal = {Journal of food science and technology}, volume = {59}, number = {12}, pages = {4863-4869}, pmid = {36276550}, issn = {0022-1155}, abstract = {This study evaluated the chlorine dioxide (ClO2) gas mediated inactivation of the biofilm cells of foodborne pathogens on food contact surfaces. Biofilm cells of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes were developed on stainless steel (SS) and high density polyethylene (HDPE) coupon surfaces, and 5-day-old biofilms were treated with ClO2 gas at 60 and 90% relative humidity (RH) for up to 20 min. With an increase in gas concentration and treatment time, significant differences (p < 0.05) were observed between reduction levels under different RH conditions. Treatment with 50 ppmv of ClO2 gas (60% RH) for 20 min resulted in log reductions from 2.08 to 4.62 and 2.08 to 4.41 of the biofilm cells of three pathogens on SS and HDPE surfaces, respectively. The levels of biofilm cells of E. coli O157:H7, S. Typhimurium, and L. monocytogenes on SS and HDPE surfaces were reduced to below the detection limit (0.48 log CFU/cm[2]) within 15, 20, and 20 min, respectively, when exposure to 50 ppmv of ClO2 gas at 90% RH.}, } @article {pmid36275203, year = {2022}, author = {Feldman, M and Moustafa Elsayed, WS and Friedman, M and Gati, I and Steinberg, D and Marei, H}, title = {Prolonged Inhibition of Streptococcus mutans Growth and Biofilm Formation by Sustained Release of Chlorhexidine from Varnish Coated Dental Abutments: An in Vitro Study.}, journal = {International journal of dentistry}, volume = {2022}, number = {}, pages = {7246155}, pmid = {36275203}, issn = {1687-8728}, abstract = {BACKGROUND: It has been confirmed that bacterial biofilm covering dental implants is the main microbial source causing preimplant infectious and inflammatory diseases. The purpose of this study was to evaluate the antibacterial/antibiofilm effect of chlorhexidine, incorporated into a sustained-release varnish of chlorhexidine (SRV-CHX) coating, on dental abutments.

MATERIALS AND METHODS: Three kinds of dental abutments were used: a high-performance semi-crystalline engineering thermoplastic polyetheretherketone (PEAK) healing abutment, a titanium healing abutment, and a titanium permanent abutment. These abutments were coated with SRV-CHX or SRV-placebo and exposed daily to fresh cultures of Streptococcus mutans. The effect of SRV-CHX on S. mutans growth on agar plates was studied by measuring the zone of inhibition (ZOI) around each tested abutment every day for a period of 36 days. Biofilm formation on the SRV-CHX/placebo-coated abutments was detected using confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), and monitored by crystal violet (CV) staining.

RESULTS: SRV-CHX-coated abutments 2 and 3 were able to inhibit S. mutans growth for 34 days, while abutment 1 inhibited growth for 32 days. Abutment-associated biofilm formation was notably inhibited by SRV-CHX coating after 13 days of incubation with S. mutans. Finally, the biofilm formed around SRV-CHX-coated abutments was completely inhibited up to 12 days of abutment exposure to S. mutans.

CONCLUSION: Coating of dental abutments with SRV-CHX demonstrated long-term effective inhibition of S. mutans growth and biofilm formation on the abutment surface.}, } @article {pmid36274728, year = {2022}, author = {Wannasrichan, W and Htoo, HH and Suwansaeng, R and Pogliano, J and Nonejuie, P and Chaikeeratisak, V}, title = {Phage-resistant Pseudomonas aeruginosa against a novel lytic phage JJ01 exhibits hypersensitivity to colistin and reduces biofilm production.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1004733}, pmid = {36274728}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa, a major cause of nosocomial infections, has been categorized by World Health Organization as a critical pathogen urgently in need of effective therapies. Bacteriophages or phages, which are viruses that specifically kill bacteria, have been considered as alternative agents for the treatment of bacterial infections. Here, we discovered a lytic phage targeting P. aeruginosa, designated as JJ01, which was classified as a member of the Myoviridae family due to the presence of an icosahedral capsid and a contractile tail under TEM. Phage JJ01 requires at least 10 min for 90% of its particles to be adsorbed to the host cells and has a latent period of 30 min inside the host cell for its replication. JJ01 has a relatively large burst size, which releases approximately 109 particles/cell at the end of its lytic life cycle. The phage can withstand a wide range of pH values (3-10) and temperatures (4-60°C). Genome analysis showed that JJ01 possesses a complete genome of 66,346 base pairs with 55.7% of GC content, phylogenetically belonging to the genus Pbunavirus. Genome annotation further revealed that the genome encodes 92 open reading frames (ORFs) with 38 functionally predictable genes, and it contains neither tRNA nor toxin genes, such as drug-resistant or lysogenic-associated genes. Phage JJ01 is highly effective in suppressing bacterial cell growth for 12 h and eradicating biofilms established by the bacteria. Even though JJ01-resistant bacteria have emerged, the ability of phage resistance comes with the expense of the bacterial fitness cost. Some resistant strains were found to produce less biofilm and grow slower than the wild-type strain. Among the resistant isolates, the resistant strain W10 which notably loses its physiological fitness becomes eight times more susceptible to colistin and has its cell membrane compromised, compared to the wild type. Altogether, our data revealed the potential of phage JJ01 as a candidate for phage therapy against P. aeruginosa and further supports that even though the use of phages would subsequently lead to the emergence of phage-resistant bacteria, an evolutionary trade-off would make them more sensitive to antibiotics.}, } @article {pmid36274516, year = {2023}, author = {Unsal, T and Xu, L and Jia, R and Kijkla, P and Kumseranee, S and Punpruk, S and Mohamed, ME and Saleh, MA and Gu, T}, title = {Microbiologically influenced corrosion of titanium by Desulfovibrio vulgaris biofilm under organic carbon starvation.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {149}, number = {}, pages = {108307}, doi = {10.1016/j.bioelechem.2022.108307}, pmid = {36274516}, issn = {1878-562X}, mesh = {Corrosion ; *Desulfovibrio vulgaris ; Titanium ; Carbon ; Biofilms ; Riboflavin ; Steel ; *Desulfovibrio ; }, abstract = {Desulfovibrio vulgaris biofilm was pre-grown on Ti coupons for 7 d and then the biofilm covered coupons were incubated again with fresh culture media with 10 % (reduced) and 100 % (normal) carbon source levels, respectively. After the pre-growth, sessile D. vulgaris cell count reached 10[7] cells/cm[2]. The sessile cell counts were 2 × 10[7] and 4.2 × 10[7] cells/cm[2] for 10 % and 100 % carbon sources, respectively after the subsequent 7 d starvation test. The maximum pit depth after the 7 d pre-growth was 4.7 µm. After the additional 7 d of the starvation test, the maximum pit depth increased to 5.1 µm for 100 % carbon source vs 6.2 µm for 10 % carbon source. Corrosion current density (icorr) from potentiodynamic polarization data at the end of the 7 d starvation test for 10 % carbon source was more than 3 times of that for 100 % carbon source, despite a reduced sessile cell count with 10 % carbon source. The polarization resistance (Rp) started to decrease within minutes after 20 ppm (w/w) riboflavin (electron mediator) injection. The carbon starvation data and riboflavin corrosion acceleration data both suggested that D. vulgaris utilized elemental Ti as an electron source to replace carbon source as the electron donor during carbon source starvation.}, } @article {pmid36272684, year = {2022}, author = {Bhardwaj, DK and Taneja, NK and Taneja, P and Patel, P}, title = {Phenotypic and genotypic characterization of multi-drug resistant, biofilm forming, human invasive strain of Salmonella Typhimurium SMC25 isolated from poultry meat in India.}, journal = {Microbial pathogenesis}, volume = {173}, number = {Pt A}, pages = {105830}, doi = {10.1016/j.micpath.2022.105830}, pmid = {36272684}, issn = {1096-1208}, mesh = {Animals ; Humans ; *Salmonella typhimurium ; Poultry ; Caco-2 Cells ; Biofilms ; *Meat Products ; Anti-Bacterial Agents/pharmacology ; Meat ; Food Microbiology ; Mammals ; }, abstract = {Emergence of highly virulent and multi-drug resistant (MDR) strains of Salmonella in food products significantly impacts public health and demands continuous monitoring for their presence in the food chain. The ability of Salmonella to form biofilms under harsh environmental conditions accompanied by MDR serotypes underscores an important food safety threat. This study aimed to isolate, identify and characterize MDR, biofilm-forming Salmonella from local Indian dairy and meat products (n = 60). All of the 24 isolates of Salmonella produced biofilm and were categorized as strong (16.6%), moderate (58.3%), and weak (25%) biofilm producers. Multiple antimicrobial resistance (MAR) index of all the Salmonella isolates was ≥0.2. The strongest biofilm forming poultry meat isolate, Salmonella SMC25 demonstrated intermediate to complete resistance to 14 of 22 different antibiotics tested. Epifluorescence microscopy showed that biofilm formation initiated as early as 4 h, reaching zenith within 96 h and much denser and robust biofilm is formed on rough stainless steel (SS316) surface compared to smooth glass surface. The results corroborated with increased temporal production of exopolysaccharides (EPS), high cell surface hydrophobicity and upregulation of marker genes vital to biofilm-formation in Salmonella. Significantly, SMC25 was found to adhere and invade mammalian cell lines Caco2 and HepG2, thus posing a serious food safety threat. This study is important in comprehending the prevalence of multidrug resistant, biofilm-forming, invasive strains of foodborne Salmonella in Indian food products and is important for effective risk assessment besides ensuring better food safety and public health.}, } @article {pmid36272603, year = {2022}, author = {Sun, Q and Zhu, G}, title = {Deciphering the effects of antibiotics on nitrogen removal and bacterial communities of autotrophic denitrification systems in a three-dimensional biofilm electrode reactor.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {315}, number = {}, pages = {120476}, doi = {10.1016/j.envpol.2022.120476}, pmid = {36272603}, issn = {1873-6424}, mesh = {*Denitrification ; *Nitrogen/metabolism ; Nitrates ; Bioreactors ; Anti-Bacterial Agents/toxicity ; Ecosystem ; Biofilms ; Bacteria/genetics/metabolism ; Electrodes ; Wastewater ; }, abstract = {In this study, three-dimensional biofilm electrode reactors (3D-BERs) were constructed, and the effects of metronidazole (MNZ) on the nitrogen removal performance and bacterial communities of autotrophic denitrification systems were evaluated. The results showed that nitrogen removal decreased slightly as the MNZ concentration increased. Specifically, nitrate-nitrogen removal efficiency decreased from 97.98% to 89.39%, 86.93%, 82.64%, and 82.77% within 12 h after the addition of 1, 3, 5, and 10 mg/L MNZ, respectively. The 3D-BERs showed excellent MNZ degradation ability, especially at a concentration of 10 mg/L. The MNZ removal efficiency could be as high as 94.38% within 6 h, and the average removal rate increased as the MNZ concentration increased. High-throughput sequencing results showed significant changes in the bacterial community under different MNZ concentrations. As the antibiotic concentration increased, the relative abundances of Hydrogenophaga and Silanimonas increased, from only 0.09% and 0.01% without antibiotics to 3.55% and 2.35%, respectively, at an antibiotic concentration of 10 mg/L. Changes in antibiotic concentration altered the abundances of genes involved in nitrogen metabolism. Redundancy analysis showed that MNZ removal efficiency was positively correlated with SBR1031, SC-I-84, Hydrogenophaga, Silanimonas and Denitratesoma, whereas the removal efficiencies of nitrate-nitrogen and total nitrogen were negatively correlated with these genera. The results of this study provide a theoretical basis for studying the toxic effects of antibiotics on the denitrification process and also provide guidance for the control of antibiotics and nitrogen pollution in ecosystems.}, } @article {pmid36272576, year = {2022}, author = {Tong, CY and Derek, CJC}, title = {Marine microalgal biofilm development and its adhesion propensities on commercial membrane via XDLVO approach.}, journal = {Journal of biotechnology}, volume = {360}, number = {}, pages = {37-44}, doi = {10.1016/j.jbiotec.2022.10.012}, pmid = {36272576}, issn = {1873-4863}, mesh = {*Microalgae ; Polysaccharides ; }, abstract = {An emerging biofilm immobilization method has enabled effortless biomass harvesting and promoted economic feasibility. The current limitation towards the adaptation of this technology is the inadequate understanding of the biofilm interaction towards microporous membrane. Cell adhesion is recognized as the most important step towards the immobilized cultivation of microalgae. Cell attachment kinetic was studied in a short-term batch culture of three marine diatoms, Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta over 96 h on submerged commercial polyvinylidene fluoride (PVDF) membrane under swirling motion of culture medium. Both the evolution of cell adhesion intensity and compositional changes of the extracellular polymeric substances (EPS) released were quantified throughout the cultivation period. To delve into the cell-substratum interactions, existing thermodynamics and colloidal extended Derjaguin, Landau, Vervey, and Overbeek (XDLVO) theory were employed. As a result, A. coffeaeformis and N. incerta recorded a higher cell colonization percentage than C. fusiformis being the lowest about 2.16±0.17% cell colonization due to their respective species-dependent EPS variation. Polysaccharide contents were at least two times higher than protein contents for both C. fusiformis and N. incerta except for A. coffeaeformis depicting a lower polysaccharide-to-protein ratio whereby the protein contents were maximized at 1.03 × 103 ± 64.14 pg m[-2] cell[-1] at 6th h. From the surface free energy point of view, both thermodynamics and XDLVO model elucidated that cells adhered reversibly in the secondary energy minimum and ranked C. fusiformis the lowest adhesion tendency among three. These findings establish fundamental knowledge about biofilm formation in porous substrate bioreactors.}, } @article {pmid36272481, year = {2023}, author = {Nguyen, NHA and Marlita, M and El-Temsah, YS and Hrabak, P and Riha, J and Sevcu, A}, title = {Early stage biofilm formation on bio-based microplastics in a freshwater reservoir.}, journal = {The Science of the total environment}, volume = {858}, number = {Pt 1}, pages = {159569}, doi = {10.1016/j.scitotenv.2022.159569}, pmid = {36272481}, issn = {1879-1026}, mesh = {Humans ; *Microplastics ; *Plastics ; RNA, Ribosomal, 16S/genetics ; Polyethylene ; Renal Dialysis ; Fresh Water ; Biofilms ; Bacteria ; Polyesters ; }, abstract = {Bio-based plastics (BP) produced from renewable biomass resources, such as high-density polyethylene (HDPE), polylactic acid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), is currently increasing in terms of both products and applications. However, their biodegradability and environmental fate are not yet fully understood, especially in freshwaters. Here, we present the results of an in-situ study in a freshwater reservoir, where we submerged HDPE, PLA and PHBV microscale BP (mBP) in dialysis bags to enable exchange of small organic and inorganic molecules, including nutrients, with the surrounding water. After one and two months, the bacterial biofilm that formed on each mBP was characterised by 16S rRNA amplicon sequencing. After two-months, Oxalobacteraceae, Pedosphaeraceae, Flavobacteriaceae (Flavobacterium) and Chitinophagaceae (Ferruginibacter) had increased by up to four times. Both these and other common members (≥1 % relative total biomass) of the microbial community were similarly abundant on all mBP. Low-abundance (0.3-1 %) bacterial taxa, however, were significantly more diverse and differed on each mBP. Notably, some low-abundance families and genera increased on specific materials, e.g. Sphingomonadaceae on HDPE, Sphingobacteriaceae on PHBV, Gemmatimonas and Crenothrix on PLA. Overall, abundant bacteria were regarded as a pioneering community, while low-abundance bacteria were more diverse and preferred mBP types in the early stages of biofilm formation on mBP. It could be influenced by the environmental conditions, where nutrient levels and low temperatures might shape the low-abundance of attached bacterial communities than the plastic material itself.}, } @article {pmid36271327, year = {2022}, author = {Anari, RK and Nikkhahi, F and Javadi, A and Bakht, M and Rostamani, M and Kelishomi, FZ and Alizadeh, SA}, title = {Evaluation of antibacterial activity of five biocides and the synergistic effect of biocide/EDTA combinations on biofilm-producing and non-producing Stenotrophomonas maltophilia strains isolated from clinical specimens in Iran.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {257}, pmid = {36271327}, issn = {1471-2180}, mesh = {Humans ; *Stenotrophomonas maltophilia ; Ceftazidime/pharmacology ; Edetic Acid/pharmacology ; Ticarcillin/pharmacology ; Iran ; *Disinfectants/pharmacology ; Sodium Hypochlorite/pharmacology ; Microbial Sensitivity Tests ; *Gram-Negative Bacterial Infections/microbiology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cross Infection/microbiology ; Chloramphenicol/pharmacology ; Clavulanic Acid/pharmacology ; Ethanol/pharmacology ; }, abstract = {BACKGROUND: The overuse of biocides in healthcare-facilities poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. Hospital-acquired infections due to S. maltophilia have been increased in the recent years and with its various resistance mechanisms contribute to patient morbidity and mortality in hospitals. The current study aimed to evaluate the susceptibility of biofilm-producing and non-producing S. maltophilia clinical isolates to five commonly used hospital biocides, alone and in combination with EDTA to examine the synergistic effect of combining EDTA on the bactericidal activity of them by microbroth dilution method. As well as the frequency of efflux genes encoding resistance to biocides among isolates. This study also intended to assess the effect of exposure of S. maltophilia isolates to sub-inhibitory concentrations of sodium hypochlorite upon the antimicrobial susceptibility patterns.

RESULTS: Based on minimum inhibitory and bactericidal concentrations of biocides sodium hypochlorite 5% (w/v) and ethyl alcohol 70% (v/v) were the strongest and weakest biocides against S. maltophilia isolates, respectively. The combination of EDTA with biocides significantly increased the effectiveness of the studied biocides. Exposure to sub-inhibitory concentration of sodium hypochlorite showed a significant change in the susceptibility of isolates towards ceftazidime (p = 0.019), ticarcillin/clavulanate (p = 0.009), and chloramphenicol (p = 0.028). As well as among the isolates examined, 94 (95%) were able to produce biofilm. The frequency of sugE1 resistance genes was found in 90.7% of our clinical S. maltophilia isolates. None of the isolates carried qacE and qacEΔ1 gene.

CONCLUSIONS: The current study recommended that using the mixture of biocides with EDTA can be effective in reducing nosocomial infections. Also, this study demonstrated that exposure to sub-inhibitory concentrations of sodium hypochlorite leads to reduced antibiotic susceptibility and development of multidrug-resistant S. maltophilia strains.}, } @article {pmid36270969, year = {2023}, author = {Yan, Y and Hailun, H and Fenghui, Y and Pingting, L and Lei, L and Zhili, Z and Tao, H}, title = {Streptococcus mutans dexA affects exopolysaccharides production and biofilm homeostasis.}, journal = {Molecular oral microbiology}, volume = {38}, number = {2}, pages = {134-144}, doi = {10.1111/omi.12395}, pmid = {36270969}, issn = {2041-1014}, support = {2020JJ4459//Hunan Provincial Natural Science Foundation of China/ ; 2017JJ3403//Hunan Provincial Natural Science Foundation of China/ ; 81702709//National Natural Science Foundation of China/ ; RD-02-202001//West China Hospital of Stomatology, Research and Develop Program/ ; 2020JGB116//Central South University Education and Teaching Reform Project/ ; 2020jy137-2//Central South University Education and Teaching Reform Project/ ; }, mesh = {Humans ; *Streptococcus mutans ; Biofilms ; Streptococcus sanguis ; Streptococcus gordonii/genetics ; *Dental Caries/microbiology ; Homeostasis ; }, abstract = {OBJECTIVES: The study aimed to evaluate the role of Streptococcus mutans (S. mutans) dexA gene on biofilm structure and microecological distribution in multispecies biofilms.

MATERIALS AND METHODS: A multispecies biofilm model consisting of S. mutans and its dexA mutants, Streptococcus gordonii (S. gordonii) and Streptococcus sanguinis (S. sanguinis) was constructed, and bacterial growth, biofilm architecture and microbiota composition were determined to study the effect of the S. mutans dexA on multispecies biofilms.

RESULTS: Our results showed that either deletion or overexpression of S. mutans dexA had no effect on the planktonic growth of bacterium, while S. mutans dominated in the multispecies biofilms to form cariogenic biofilms. Furthermore, we revealed that the SmudexA+ group showed structural abnormality in the form of more fractures and blank areas. The morphology of the SmudexA group was sparser and more porous, with reduced and less agglomerated exopolysaccharides scaffold. Interestingly, the microbiota composition analysis provided new insights that the inhibition of S. gordonii and S. sanguinis was alleviated in the SmudexA group compared to the significantly suppressed condition in the other groups.

CONCLUSION: In conclusion, deletion of S. mutans dexA gene re-modules biofilm structure and microbiota composition, thereby leading to decreased cariogenicity. Thus, the S. mutans dexA may be an important target for regulating the cariogenicity of dental plaque biofilms, expecting to be a probiotic for caries control.}, } @article {pmid36270222, year = {2023}, author = {Simões, LC and Chaves, AFA and Simões, M and Lima, N}, title = {Interactions between Penicillium brevicompactum/Penicillium expansum and Acinetobacter calcoaceticus isolated from drinking water in biofilm development and control.}, journal = {International journal of food microbiology}, volume = {384}, number = {}, pages = {109980}, doi = {10.1016/j.ijfoodmicro.2022.109980}, pmid = {36270222}, issn = {1879-3460}, mesh = {*Drinking Water/microbiology ; *Acinetobacter calcoaceticus ; Biofilms ; Bacteria ; Sodium Hypochlorite ; Fungi ; }, abstract = {Bacteria and filamentous fungi (ff) are commonly encountered in biofilms developed in drinking water (DW) distribution systems (DWDS). Despite their intimate ecological relationships, researchers tend to study bacteria and ff separately. This work assesses the impact of bacteria-ff association in biofilm formation and tolerance to chlorination. One strain of Acinetobacter calcoaceticus isolated from DW was used as a model bacterium. Penicillium brevicompactum and P. expansum isolated from DW were the ff selected. Single species and inter-kingdom adhesion and biofilm formation occurred under two shear stress (τ) conditions (0.05 and 1.6 Pa). The sessile structures were further characterized in terms of biomass production, respiratory activity and structure. The results showed that 1.6 Pa of shear stress and A. calcoaceticus-ff association favoured biofilm production. Inter-kingdom biofilms produced more biomass than A. calcoaceticus single species and reduced A. calcoaceticus susceptibility to disinfection, particularly to high sodium hypochlorite (SHC) concentrations. In addition, P. brevicompactum formed single species biofilms highly resistant to removal and inactivation by SHC. The presence of P. brevicompactum or P. expansum in inter-kingdom biofilms significantly decreased SHC removal and inactivation effects in comparison to the bacterial biofilms alone, proposing that using bacteria to form biofilms representative of DWDS can provide inaccurate conclusions, particularly in terms of biofilm production and susceptibility to disinfection.}, } @article {pmid36270212, year = {2023}, author = {Fernandes, L and Costa, R and Henriques, M and Rodrigues, ME}, title = {Simulated vaginal fluid: Candida resistant strains' biofilm characterization and vapor phase of essential oil effect.}, journal = {Journal de mycologie medicale}, volume = {33}, number = {1}, pages = {101329}, doi = {10.1016/j.mycmed.2022.101329}, pmid = {36270212}, issn = {1773-0449}, mesh = {Female ; Humans ; Candida ; Antifungal Agents/pharmacology/therapeutic use ; *Candidiasis, Vulvovaginal/drug therapy/microbiology ; *Oils, Volatile/pharmacology ; Candida albicans ; Biofilms ; Microbial Sensitivity Tests ; }, abstract = {INTRODUCTION: Vulvovaginal candidiasis is a disease that affects millions of women worldwide. Oral formulations, topical creams or ointments are the conventional dosage forms, with an increase in drug administration through vaginal via. The use of simulated biological fluids (e.g. vaginal fluid) in the evaluation of antifungal therapies may better mimic the real biological environments and therefore provide a better understanding of the behavior of the antifungal.

METHODS: The main objective of this work was to compare planktonic growth and biofilm formation of Candida species, on common growth medium, Sabouraud Dextrose Broth (SDB) and on vaginal simulation conditions, Simulated Vaginal Fluid (SVF), through the optical density determination, colony-forming units and scanning electron microscopy. In addition, under the same conditions this study also evaluated the ability of vapor phase of oregano and white thyme essential oils (VP-EOs), potential alternative treatment, to inhibit biofilm formation and to destroy mature biofilms of vaginal isolates, through the colony-forming units determination.

RESULTS: Candida isolates maintained the same biofilm formation capacity and morphology in both media (SVF and SDB). Furthermore, the results obtained in this work related with VP-EOs effect agree with results acquired, previously, with SDB. This means that the effect of VP-EOs is not affected by the SVF medium, and that this fluid allows the dissolution of the volatile and bioactive compounds.

CONCLUSIONS: These results can predict the in vivo behavior, suggesting a potential effective application of VP-EOs as prophylactic or therapeutic treatment for biofilm-related vulvovaginal candidiasis.}, } @article {pmid36270147, year = {2022}, author = {Lu, JJ and Zhang, H and Li, W and Yi, JB and Sun, FY and Zhao, YW and Feng, L and Li, Z and Dong, WY}, title = {Biofilm stratification in counter-diffused membrane biofilm bioreactors (MBfRs) for aerobic methane oxidation coupled to aerobic/anoxic denitrification: Effect of oxygen pressure.}, journal = {Water research}, volume = {226}, number = {}, pages = {119243}, doi = {10.1016/j.watres.2022.119243}, pmid = {36270147}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; In Situ Hybridization, Fluorescence ; *Methane ; Oxidation-Reduction ; Oxygen ; }, abstract = {Aerobic methane oxidation coupled with denitrification (AME-D) executed in membrane biofilm bioreactors (MBfRs) provides a high promise for simultaneously mitigating methane (CH4) emissions and removing nitrate in wastewater. However, systematically experimental investigation on how oxygen partial pressure affects the development and characteristics of counter-diffusional biofilm, as well as its spatial stratification profiles, and the cooperative interaction of the biofilm microbes, is still absent. In this study, we combined Optical Coherence Tomography (OCT) with Confocal Laser Scanning Microscopy (CLSM) to in-situ characterize the development of counter-diffusion biofilm in the MBfR for the first time. It was revealed that oxygen partial pressure onto the MBfR was capable of manipulating biofilm thickness and spatial stratification, and then managing the distribution of functional microbes. With the optimized oxygen partial pressure of 5.5 psig (25% oxygen content), the manipulated counter-diffusional biofilm in the AME-D process obtained the highest denitrification efficiency, due mainly to that this biofilm had the proper dynamic balance between the aerobic-layer and anoxic-layer where suitable O2 gradient and sufficient aerobic methanotrophs were achieved in aerobic-layer to favor methane oxidation, and complete O2 depletion and accessible organic sources were kept to avoid constraining denitrification activity in anoxic-layer. By using metagenome analysis and Fluorescence in situ hybridization (FISH) staining, the spatial distribution of the functional microbes within counter-diffused biofilm was successfully evidenced, and Rhodocyclaceae, one typical aerobic denitrifier, was found to survive and gradually enriched in the aerobic layer and played a key role in denitrification aerobically. This in-situ biofilm visualization and characterization evidenced directly for the first time the cooperative path of denitrification for AME-D in the counter-diffused biofilm, which involved aerobic methanotrophs, heterotrophic aerobic denitrifiers, and heterotrophic anoxic denitrifiers.}, } @article {pmid36268224, year = {2022}, author = {Chang, AW and Dowd, SE and Brackee, G and Fralick, JA and Vediyappan, G}, title = {Inhibition of Staphylococcus aureus biofilm formation by gurmarin, a plant-derived cyclic peptide.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1017545}, pmid = {36268224}, issn = {2235-2988}, mesh = {Rats ; Animals ; Staphylococcus aureus ; Peptides, Cyclic/pharmacology ; *Staphylococcal Infections/drug therapy/microbiology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; *Disinfectants/pharmacology ; *Sepsis ; Transferases/pharmacology ; Hydrolases ; Oxidoreductases ; }, abstract = {Staphylococcus aureus (Sa) is an opportunistic pathogen capable of causing various infections ranging from superficial skin infections to life-threatening severe diseases including pneumonia and sepsis. Sa produces biofilms readily on biotic and abiotic surfaces. Biofilm cells are embedded in a protective polysaccharide matrix and show an innate resistance to antibiotics, disinfectants, and clearance by host defenses. Additionally, biofilms serve as a source for systemic dissemination. Moreover, infections associated with biofilms may result in longer hospitalizations, a need for surgery, and may even result in death. Agents that inhibit the formation of biofilms and virulence without affecting bacterial growth to avoid the development of drug resistance could be useful for therapeutic purposes. In this regard, we identified and purified a small cyclic peptide, gurmarin, from a plant source that inhibited the formation of Sa biofilm under in vitro growth conditions without affecting the viability of the bacterium. The purified peptide showed a predicted molecular size of ~4.2 kDa on SDS-PAGE. Transcriptomic analysis of Sa biofilm treated with peptide showed 161 differentially affected genes at a 2-fold change, and some of them include upregulation of genes involved in oxidoreductases and downregulation of genes involved in transferases and hydrolases. To determine the inhibitory effect of the peptide against Sa biofilm formation and virulence in vivo, we used a rat-implant biofilm model. Sa infected implants with or without peptide were placed under the neck skin of rats for seven days. Implants treated with peptide showed a reduction of CFU and lack of edema and sepsis when compared to that of control animals without peptide. Taken together, gurmarin peptide blocks Sa biofilm formation in vitro and in vivo and can be further developed for therapeutic use.}, } @article {pmid36267191, year = {2022}, author = {Yang, W and Yan, H and Dong, G and Li, Z and Jiang, C and Gu, D and Niu, D and Zhou, D and Luo, Y}, title = {Comparative transcriptomics reveal different genetic adaptations of biofilm formation in Bacillus subtilis isolate 1JN2 in response to Cd[2+] treatment.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1002482}, pmid = {36267191}, issn = {1664-302X}, abstract = {Biofilm plays important roles in the life cycle of Bacillus species, such as promoting host and object surface colonization and resisting heavy metal stress. This study utilized transcriptomics to evaluate the impacts of cadmium on the components, morphology, and function of biofilms of Bacillus subtilis strain 1JN2. Under cadmium ion stress, the morphology of the B. subtilis 1JN2 biofilm was flattened, and its mobility increased. Moreover, differential gene expression analysis showed that the main regulator of biofilm formation, Spo0A, decreased in expression under cadmium ion stress, thereby inhibiting extracellular polysaccharide synthesis through the SinI/SinR two-component regulatory system and the AbrB pathway. Cadmium ion treatment also increased the SigD content significantly, thereby increasing the expression of the flagella encoding and assembly genes in the strain. This promoted poly-γ-glutamic acid production via the DegS/DegU two-component regulatory system and the conversion of biofilm extracellular polysaccharide to poly-γ-glutamic acid. This conferred cadmium stress tolerance in the strain. Additionally, the cadmium ion-mediated changes in the biofilm composition affected the colonization of the strain on the host plant root surface. Cadmium ions also induced surfactin synthesis. These findings illustrate the potential of Bacillus species as biocontrol strains that can mitigate plant pathogenic infections and heavy metal stress. The results also provide a basis for the screening of multifunctional biocontrol strains.}, } @article {pmid36265789, year = {2022}, author = {Bian, X and Wu, Y and Li, J and Yin, M and Li, D and Pei, H and Chang, S and Guo, W}, title = {Effect of dissolved oxygen on high C/N wastewater treatment in moving bed biofilm reactors based on heterotrophic nitrification and aerobic denitrification: Nitrogen removal performance and potential mechanisms.}, journal = {Bioresource technology}, volume = {365}, number = {}, pages = {128147}, doi = {10.1016/j.biortech.2022.128147}, pmid = {36265789}, issn = {1873-2976}, mesh = {*Nitrification ; Denitrification ; Nitrogen/metabolism ; Oxygen/metabolism ; Wastewater ; Heterotrophic Processes ; *Water Purification ; Biofilms ; Bioreactors/microbiology ; }, abstract = {In this study, it was investigated the nitrogen removal (NR) performance and potential mechanism for high C/N wastewater treatment under different dissolved oxygen (DO) concentrations. The results showed that DO concentration significantly affected the removal efficiency of total nitrogen (TN). When the initial DO increased from 0.5 to 1.5 mg/L, TN removal efficiency significantly increased from 65 % to 85 %. However, a further DO increase did not promote TN removal, and the NR was only 80 % with an initial DO concentration of 3.5 mg/L. The effect of DO concentration on NR was influenced by the combined action of functional bacteria and electron flow. Excessive DO concentration did not positively affect NR efficiency but promoted electron utilization and respiratory proliferation. When the DO concentration was 1.5 mg/L, more electrons generated by sodium acetate metabolism were transferred to the aerobic denitrification process, compared to when the DO concentration was 3.5 mg/L.}, } @article {pmid36265230, year = {2023}, author = {Chen, X and Lian, XY and Wang, Y and Chen, S and Sun, YR and Tao, GL and Tan, QW and Feng, JC}, title = {Impacts of hydraulic conditions on microplastics biofilm development, shear stresses distribution, and microbial community structures in drinking water distribution pipes.}, journal = {Journal of environmental management}, volume = {325}, number = {Pt A}, pages = {116510}, doi = {10.1016/j.jenvman.2022.116510}, pmid = {36265230}, issn = {1095-8630}, mesh = {Humans ; Microplastics ; Plastics ; *Drinking Water ; Biofilms ; *Microbiota ; }, abstract = {Both microplastic and biofilm are contamination sources in drinking water, but their integrated impacts on water quality have been rarely studied, especially in drinking water distribution pipes with complex hydraulic conditions. This study explored the impacts of hydraulic conditions (0-2 m/s) on microplastic biofilm (MP-BM) development, shear stresses distribution, and microbial community structures. The research was conducted for two weeks using a pilot test device to simulate practical water pipes. The following were the primary conclusions: (1) According to morphology analysis, clusters (>5 μm) significantly increased in the plastisphere when the flow velocity ranged from 0.55 m/s to 0.95 m/s, and average size of clusters decreased when the flow velocity ranged from 1.14 m/s to 1.40 m/s (2) Characteristics of MP-BM impact shear stress on both plastisphere and pipe wall biofilm. Shear stresses were positively correlated with flow velocity, number of MP-BM, and size of MP-BM, while negatively correlated with diameters of pipes. (3) 31 genera changed strictly and monotonously with the fluid velocity, accounting for 15.42%. Opportunistic pathogens in MP-BM such as Sediminibacterium, Curvibacter, and Flavobacterium were more sensitive to hydraulic conditions. Moreover, microplastics (<100 μm) deserve more attention to avoid human ingestion and to prevent mechanical damage and bio-chemical risks.}, } @article {pmid36265186, year = {2023}, author = {Khanum, R and Chung, PY and Clarke, SC and Chin, BY}, title = {Lactoferrin modulates the biofilm formation and bap gene expression of methicillin-resistant Staphylococcus epidermidis.}, journal = {Canadian journal of microbiology}, volume = {69}, number = {2}, pages = {117-122}, doi = {10.1139/cjm-2022-0135}, pmid = {36265186}, issn = {1480-3275}, mesh = {*Methicillin-Resistant Staphylococcus aureus/genetics ; Lactoferrin/genetics/pharmacology ; Staphylococcus epidermidis/genetics ; Methicillin Resistance/genetics ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Gene Expression ; Microbial Sensitivity Tests ; }, abstract = {Lactoferrin is an innate glycoprotein with broad antibacterial and antibiofilm properties. The autonomous antibiofilm activity of lactoferrin against Gram-positive bacteria is postulated to involve the cell wall and biofilm components. Thus, the prevention of biomass formation and eradication of preformed biofilms by lactoferrin was investigated using a methicillin-resistant Staphylococcus epidermidis (MRSE) strain. Additionally, the ability of lactoferrin to modulate the expression of the biofilm-associated protein gene (bap) was studied. The bap gene regulates the production of biofilm-associated proteins responsible for bacterial adhesion and aggregation. In the in vitro biofilm assays, lactoferrin prevented biofilm formation and eradicated established biofilms for up to 24 and 72 h, respectively. Extensive eradication of MRSE biofilm biomass was accompanied by the significant upregulation of bap gene expression. These data suggest the interaction of lactoferrin with the biofilm components and cell wall of MRSE, including the biofilm-associated protein.}, } @article {pmid36262331, year = {2022}, author = {Lahiri, D and Ray, RR and Sarkar, T and Upadhye, VJ and Ghosh, S and Pandit, S and Pati, S and Edinur, HA and Abdul Kari, Z and Nag, M and Ahmad Mohd Zain, MR}, title = {Anti-biofilm efficacy of green-synthesized ZnO nanoparticles on oral biofilm: In vitro and in silico study.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {939390}, pmid = {36262331}, issn = {1664-302X}, abstract = {The development of biofilm on the biotic and abiotic surfaces is the greatest challenge for health care sectors. At present times, oral infection is a common concern among people with an unhealthy lifestyle and most of these biofilms-associated infections are resistant to antibiotics. This has increased a search for the development of alternate therapeutics for eradicating biofilm-associated infection. Nanobiotechnology being an effective way to combat such oral infections may encourage the use of herbal compounds, such as bio-reducing and capping agents. Green-synthesis of ZnO nanoparticles (ZnO NP) by the use of the floral extract of Clitoria ternatea, a traditionally used medicinal plant, showed stability for a longer period of time. The NPs as depicted by the TEM image with a size of 10 nm showed excitation spectra at 360 nm and were found to remain stable for a considerable period of time. It was observed that the NPs were effective in the eradication of the oral biofilm formed by the major tooth attacking bacterial strains namely Porphyromonsas gingivalis and Alcaligenes faecalis, by bringing a considerable reduction in the extracellular polymeric substances (EPS). It was observed that the viability of the Porphyromonsas gingivalis and Alcaligenes faecalis was reduced by NP treatment to 87.89 ± 0.25% in comparison to that of amoxicillin. The results went in agreement with the findings of modeling performed by the use of response surface methodology (RSM) and artificial neural network (ANN). The microscopic studies and FT-IR analysis revealed that there was a considerable reduction in the biofilm after NP treatment. The in silico studies further confirmed that the ZnO NPs showed considerable interactions with the biofilm-forming proteins. Hence, this study showed that ZnO NPs derived from Clitoria ternatea can be used as an effective alternative therapeutic for the treatment of biofilm associated oral infection.}, } @article {pmid36260227, year = {2023}, author = {Hu, Y and Chen, C and Liu, S and Zhou, Y and Jia, W and Cao, Y}, title = {Biofilm-induced corrosion inhibition of Q235 carbon steel by anaerobic Bacillus cereus inoculum in simulated cooling water.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {8}, pages = {20833-20848}, pmid = {36260227}, issn = {1614-7499}, mesh = {*Steel/chemistry ; *Bacillus cereus ; Water ; Corrosion ; Carbon ; Anaerobiosis ; Biofilms ; }, abstract = {In this study, the corrosion behavior of Q235 carbon steel (CS) under a Bacillus cereus (B. cereus) inoculum in simulated cooling water was evaluated. The weight loss study proved B. cereus inoculum possessed anticorrosion efficiencies of 92.84% and 73.88% for 3-day and 14-day rotation tests, respectively. The electrochemical measurements indicated that the added B. cereus inoculum increased the charge transfer resistance and reduced corrosion current density. B. cereus cells with strong biofilm-forming capacity were able to adhere onto the Q235 CS surface to form compact biofilms and cause biomineralization. Surface characterization analysis demonstrated that the presence of the B. cereus inoculum reduced the amount of Fe2O3 and simultaneously increased the amount of CaCO3 in corrosion products. The corrosion inhibition mechanisms of the B. cereus inoculum involve forming biofilm, generating a biomineralized layer, and consuming dissolved oxygen. Thus, B. cereus inoculum provides a biological strategy for industrial cooling water anticorrosion application.}, } @article {pmid36259551, year = {2023}, author = {Voss-Rech, D and Ziech, RE and Vaz, CSL and Coldebella, A and Kuchiishi, SS and Balzan, C and Matter, L and Vargas, ÁC and Botton, SA}, title = {Association between antimicrobial resistance and biofilm forming ability of Salmonella enterica serotypes from commercial broiler farms in Brazil.}, journal = {British poultry science}, volume = {64}, number = {2}, pages = {224-230}, doi = {10.1080/00071668.2022.2136511}, pmid = {36259551}, issn = {1466-1799}, mesh = {Animals ; *Anti-Bacterial Agents/pharmacology ; *Salmonella enterica ; Serogroup ; Farms ; Brazil ; Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial ; Chickens ; Salmonella ; Biofilms ; Microbial Sensitivity Tests/veterinary ; }, abstract = {1. This study determined the antimicrobial resistance profile and the biofilm-forming ability of Salmonella enterica strains isolated from commercial broiler houses over a three-year period in southern Brazil.2. Of the 720 drag swabs analysed, 37 (5%) tested positive for non-typhoidal Salmonella spp. and S. Heidelberg was the most frequent serovar.3. Among the antimicrobial resistant strains (83.8%; 31/37), resistance was most common to tetracycline, ampicillin and nalidixic acid. Multidrug resistance was found in 65% (24/37) of the isolates, with a large proportion of multidrug resistant S. Heidelberg strains (81%; 13/16).4. In total, 65% (24/37) of the isolates showed the ability to produce biofilm and multiple antimicrobial resistance was negatively correlated with biofilm formation.5. Strains susceptible to all tested antimicrobials tended to form stronger biofilms than multidrug resistant ones. This suggested that Salmonella spp. with less antimicrobial resistance depend more on the protection provided by biofilm to survive in the farm environment.}, } @article {pmid36258069, year = {2022}, author = {Park, S and Sauer, K}, title = {Controlling Biofilm Development Through Cyclic di-GMP Signaling.}, journal = {Advances in experimental medicine and biology}, volume = {1386}, number = {}, pages = {69-94}, pmid = {36258069}, issn = {0065-2598}, support = {R01 AI150761/AI/NIAID NIH HHS/United States ; }, mesh = {*Gene Expression Regulation, Bacterial ; *Bacterial Proteins/metabolism ; Cyclic GMP/metabolism ; Biofilms ; Second Messenger Systems/physiology ; Signal Transduction/physiology ; Pseudomonas aeruginosa/physiology ; }, abstract = {The cyclic di-GMP (c-di-GMP) second messenger represents a signaling system that regulates many bacterial behaviors and is of key importance for driving the lifestyle switch between motile loner cells and biofilm formers. This review provides an up-to-date summary of c-di-GMP pathways connected to biofilm formation by the opportunistic pathogen P. aeruginosa. Emphasis will be on the timing of c-di-GMP production over the course of biofilm formation, to highlight non-uniform and hierarchical increases in c-di-GMP levels, as well as biofilm growth conditions that do not conform with our current model of c-di-GMP.}, } @article {pmid36257971, year = {2022}, author = {Coenye, T and Bové, M and Bjarnsholt, T}, title = {Biofilm antimicrobial susceptibility through an experimental evolutionary lens.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {82}, pmid = {36257971}, issn = {2055-5008}, mesh = {*Biofilms ; *Anti-Bacterial Agents/pharmacology ; Bacteria/genetics ; Phenotype ; Genotype ; }, abstract = {Experimental evolution experiments in which bacterial populations are repeatedly exposed to an antimicrobial treatment, and examination of the genotype and phenotype of the resulting evolved bacteria, can help shed light on mechanisms behind reduced susceptibility. In this review we present an overview of why it is important to include biofilms in experimental evolution, which approaches are available to study experimental evolution in biofilms and what experimental evolution has taught us about tolerance and resistance in biofilms. Finally, we present an emerging consensus view on biofilm antimicrobial susceptibility supported by data obtained during experimental evolution studies.}, } @article {pmid36257185, year = {2023}, author = {Sathiyamoorthi, E and Faleye, OS and Lee, JH and Lee, J}, title = {Hydroquinone derivatives attenuate biofilm formation and virulence factor production in Vibrio spp.}, journal = {International journal of food microbiology}, volume = {384}, number = {}, pages = {109954}, doi = {10.1016/j.ijfoodmicro.2022.109954}, pmid = {36257185}, issn = {1879-3460}, mesh = {Humans ; *Virulence Factors ; Hydroquinones/pharmacology ; Biofilms ; *Vibrio parahaemolyticus ; Anti-Bacterial Agents/pharmacology ; }, abstract = {Gram-negative Vibrio parahaemolyticus is a halophilic human pathogen known to be the leading cause of food poisoning associated with consuming uncooked or undercooked seafood. The increasing presence and contamination of seafood have caused serious safety concerns in food facilities. Notably, it can form biofilms on food surfaces that confer resistance to antimicrobial treatments. Therefore, in the present study, the antibacterial, antibiofilm, and antivirulence activities of hydroquinone (HQ) and its 16 derivatives were investigated against V. parahaemolyticus and V. harveyi. Representative active antibacterial and antibiofilm compounds, 2,3-dimethylhydroquinone (2,3-DMHQ) and 2,5-ditert-butylhydroquinone (DBHQ), were further examined using a crystal violet assay, biochemical reactions, live cell imaging, and scanning electron microscopy. 2,3-DMHQ with a minimum inhibitory concentration (MIC) of 20 μg/mL completely inhibited biofilm formation at a sub-MIC of 15 μg/mL. And, DBHQ with an MIC of ˃1000 μg/mL reduced biofilm formation by 70 % at sub-MIC of 25 μg/mL. Both 2,3-DMHQ and DBHQ inhibited protease and indole production as well as motility phenotypes. 2,3-DMHQ decreased fimbriae production and hydrophobicity whereas DBHQ did not. Transcriptomic studies revealed that genes related to biofilm, quorum sensing (QS), and hemolysin were downregulated. In addition, 2,3-DMHQ and DBHQ prevented biofilm formation of V. parahaemolyticus on squid surfaces and 2,3-DMHQ reduced the presence of V. parahaemolyticus in a boiled shrimp model. Toxicity assays using the Caenorhabditis elegans and seed germinations models showed that they were non-to-mildly toxic. These results suggest that 2,3-DMHQ and DBHQ possess the antimicrobial properties required to control V. parahaemolyticus planktonic and biofilm states in food production facilities.}, } @article {pmid36255599, year = {2023}, author = {Madan, R and Madan, S and Hussain, A}, title = {Correction to: Kinetic Study for Startup of Aerobic Moving Bed Biofilm Reactor in Treatment of Textile Dye Wastewater.}, journal = {Applied biochemistry and biotechnology}, volume = {195}, number = {2}, pages = {1603}, doi = {10.1007/s12010-022-04196-w}, pmid = {36255599}, issn = {1559-0291}, } @article {pmid36255295, year = {2022}, author = {Armes, AC and Walton, JL and Buchan, A}, title = {Quorum Sensing and Antimicrobial Production Orchestrate Biofilm Dynamics in Multispecies Bacterial Communities.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0261522}, pmid = {36255295}, issn = {2165-0497}, mesh = {*Quorum Sensing ; Ecosystem ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Bacteria/metabolism ; *Anti-Infective Agents/pharmacology ; }, abstract = {Microbial interactions are often mediated by diffusible small molecules, including secondary metabolites, that play roles in cell-to-cell signaling and inhibition of competitors. Biofilms are often "hot spots" for high concentrations of bacteria and their secondary metabolites, which make them ideal systems for the study of small-molecule contributions to microbial interactions. Here, we use a five-member synthetic community consisting of Roseobacteraceae representatives to investigate the role of secondary metabolites on microbial biofilm dynamics. One synthetic community member, Rhodobacterales strain Y4I, possesses two acylated homoserine lactone (AHL)-based cell-to-cell signaling systems (pgaRI and phaRI) as well as a nonribosomal peptide synthase gene (igi) cluster that encodes the antimicrobial indigoidine. Through serial substitution of Y4I with mutants deficient in single signaling molecule pathways, the contribution of these small-molecule systems could be assessed. As secondary metabolite production is dependent upon central metabolites, the influence of growth substrate (i.e., complex medium versus defined medium with a single carbon substrate) on these dynamics was also considered. Depending on the Y4I mutant genotype included, community dynamics ranged from competitive to cooperative. The observed interactions were mostly competitive in nature. However, the community harboring a Y4I variant that was both impaired in quorum sensing (QS) pathways and unable to produce indigoidine (pgaR variant) shifted toward more cooperative interactions over time. These cooperative interactions were enhanced in the defined growth medium. The results presented provide a framework for deciphering complex, small-molecule-mediated interactions that have broad application to microbial biology. IMPORTANCE Microbial biofilms play critical roles in marine ecosystems and are hot spots for microbial interactions that play a role in the development and function of these communities. Roseobacteraceae are an abundant and active family of marine heterotrophic bacteria forming close associations with phytoplankton and carrying out key transformations in biogeochemical cycles. Group members are aggressive primary colonizers of surfaces, where they set the stage for the development of multispecies biofilm communities. Few studies have examined the impact of secondary metabolites, such as cell-to-cell signaling and antimicrobial production, on marine microbial biofilm community structure. Here, we assessed the impact of secondary metabolites on microbial interactions using a synthetic, five-member Roseobacteraceae community by measuring species composition and biomass production during biofilm growth. We present evidence that secondary metabolites influence social behaviors within these multispecies microbial biofilms, thereby improving understanding of bacterial secondary metabolite production influence on social behaviors within marine microbial biofilm communities.}, } @article {pmid36254986, year = {2023}, author = {Santos, J and Ventura, S and Pallarès, I}, title = {LL-37 and CsgC exemplify the crosstalk between anti-amyloid, antimicrobial, and anti-biofilm protein activities.}, journal = {Neural regeneration research}, volume = {18}, number = {5}, pages = {1027-1028}, pmid = {36254986}, issn = {1673-5374}, } @article {pmid36254653, year = {2022}, author = {Chen, X and Chen, Y and Zhang, R and Ye, S and Lin, Z and Nian, S and Lin, C}, title = {The biofilm characteristics and management of skin flap infection following cochlear implantation.}, journal = {Acta otorhinolaryngologica Italica : organo ufficiale della Societa italiana di otorinolaringologia e chirurgia cervico-facciale}, volume = {42}, number = {4}, pages = {372-379}, pmid = {36254653}, issn = {1827-675X}, mesh = {Bacteria ; Biofilms ; Child ; *Cochlear Implantation ; *Cochlear Implants/adverse effects/microbiology ; Humans ; Postoperative Complications/etiology ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {OBJECTIVE: This study aims to assess the frequency, bacteriology, biofilm characteristics and management of skin flap infection (SFI) following cochlear implantation (CI).

METHODS: The study enrolled 1,251 patients receiving CI in the First Affiliated Hospital of Fujian Medical University between August 2001 and March 2021. Scanning electron microscopy (SEM) was utilised to characterise the aetiology of infection. A proposed classification system was applied to optimise treatments for post-operative skin flap infection.

RESULTS: After CI, SFI was reported in 16 patients (1.28%) and occurred more frequently in patients under 6 years of age. Of all SFI cases Staphylococcus aureus was the most common pathogen for flap infection, with 8 cases (50%) and bacterial biofilm was evident within the jelly-like substance on the surface of implanted devices in SFI patients. A two-stage classification was proposed to optimise the treatment schemes. Conservative therapy was recommended for stage I cases and surgical treatment for stage II patients.

CONCLUSIONS: Paediatric patients are more susceptible to SFI after CI, which may be attributed to the formation of bacterial biofilm. The proposed classification can facilitate the management of SFI.}, } @article {pmid36254114, year = {2022}, author = {Zheng, L and Zhang, X and Lu, Z and Ma, W and Hu, A and Zhou, H and Bie, X}, title = {Transcriptome sequencing reveals the difference in the expression of biofilm and planktonic cells between two strains of Salmonella Typhimurium.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100086}, pmid = {36254114}, issn = {2590-2075}, abstract = {Salmonela enterica serovar Typhimurium (S. Typhimurium) is a food-borne pathogen that can form biofilms to increase its resistance to the external environment. Through the detection of biofilm of several S. Typhimurium strains in this study, strain CDC3 with strong biofilm forming capacity and strain CVCC3384 with weak biofilm forming capacity were identified. The genes expressed in planktonic and biofilm cells of two S. Typhimurium strains were analysed by transcriptome sequencing. Results showed that the genes related to the signal transduction pathway were upregulated and genes related to motility were downregulated in strain CDC3. By comparing biofilms and planktonic cells of the two strains, we found that CDC3 regulates biofilm formation mainly through the two-component system kdpABC, while strain CVCC3384 does so mainly through motility and quorum sensing. This study revealed regulation mechanism of biofilms formation between different biofilm forming capacity strains, and provided a theoretical basis for subsequent research.}, } @article {pmid36253652, year = {2022}, author = {Safai, SM and Khorsandi, K and Falsafi, S}, title = {Effect of Berberine and Blue LED Irradiation on Combating Biofilm of Pseudomonas aeruginosa and Staphylococcus aureus.}, journal = {Current microbiology}, volume = {79}, number = {12}, pages = {366}, pmid = {36253652}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Berberine/pharmacology/therapeutic use ; Biofilms ; Humans ; Pseudomonas aeruginosa ; Reactive Oxygen Species ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Nowadays, with increasing resistance of microorganisms to drugs, it is necessary to look for new solutions beside antibiotic therapy. One of these effective approaches is the use of plant compounds and blue LED Irradiation. Berberine (an alkaloid compound) has several properties, including antibacterial effect. This compound destroys bacterial cells by producing reactive oxygen species (ROS). In this study, the combined effect of blue LED Irradiation and berberine on Pseudomonas aeruginosa (Gram-negatives) and Staphylococcus aureus (Gram-positive) and also their effect on human dermal fibroblast (HDF) cells were investigated. The obtained results showed that the combination of berberine and blue light irradiation had a better effect on both bacteria and this antimicrobial effect was higher in Gram-positive bacteria. These compounds also prevented the formation of biofilms and were able to destroy the created biofilms. Therefore, this method can be suggested to treat infection in chronic wounds, such as diabetic wounds.}, } @article {pmid36253556, year = {2022}, author = {Choudhary, M and Shrivastava, R and Vashistt, J}, title = {Acinetobacter baumannii Biofilm Formation: Association with Antimicrobial Resistance and Prolonged Survival under Desiccation.}, journal = {Current microbiology}, volume = {79}, number = {12}, pages = {361}, pmid = {36253556}, issn = {1432-0991}, support = {YSS/2014/000548//Science and Engineering Research Board (SERB), New Delhi, India/ ; }, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Desiccation ; Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Biofilm-forming multidrug-resistant Acinetobacter baumannii has emerged as a global pathogen. This study investigated the impact of biofilm formation by A. baumannii on antimicrobial resistance and prolonged survival under desiccation, which is essential for effective infection control of A. baumannii in hospital settings. Seventy-eight clinical isolates of A. baumannii were identified, and antibiotic susceptibility profiles were assessed. All the isolates were investigated for their biofilm-forming abilities at 24 and 48 h. The biofilm inhibitory concentrations of antibiotics were evaluated for selected biofilm-forming isolates to determine the influence of biofilm on antibiotic tolerance. The impact of biofilm formation on desiccation tolerance was also evaluated for up to 48 days. The results revealed that out of 78 A. baumannii clinical isolates, 83% were MDR and 17% non-MDR. Overall, 79% of isolates formed high biofilm after 24 h. The extent of biofilm formation gets significantly increased after 48 h, and 87% of isolates formed high biofilm. It was observed that eradicating mature biofilm requires up to a thousandfold higher concentration of antibiotics than MICs, and biofilm-forming isolates can survive for a prolonged period under desiccation. In conclusion, our findings revealed that both MDR and non-MDR isolates of A. baumannii could form biofilms on abiotic surfaces. A. baumannii biofilms contribute to endurance in the presence of antimicrobials and desiccation conditions, which are significant trouble for hospital patient care management. The present findings may offer insights for developing preventive measures to tackle biofilm-associated A. baumannii infection.}, } @article {pmid36252425, year = {2022}, author = {Rodrigues, RAA and Silva, RMFDCE and Ferreira, LAQ and Branco, NTT and Ávila, ÉS and Peres, AM and Fernandes-Braga, W and Sette-Dias, AC and Andrade, ÂL and Palma-Dibb, RG and Magalhães, CS and Ladeira, LO and Silveira, RRD and Moreira, AN and Martins Júnior, PA and Yamauti, M and Diniz, IMA}, title = {Enhanced mechanical properties, anti-biofilm activity, and cytocompatibility of a methacrylate-based polymer loaded with native multiwalled carbon nanotubes.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {136}, number = {}, pages = {105511}, doi = {10.1016/j.jmbbm.2022.105511}, pmid = {36252425}, issn = {1878-0180}, abstract = {OBJECTIVES: We aimed to optimize the mechanical and biological properties of a conventional methacrylate-based dental polymer by loading it with double- and triple-walled carbon nanotubes as growth (DTWCNTG).

METHODS: A formulation of bisphenol A-glycidyl methacrylate and triethylene glycol dimethacrylate (mass ratio = 2:1) was mixed with DTWCNTG at concentrations of 0.0% (control), 0.001%, 0.005%, and 0.010%. The concentrations were physicochemical and morphologically evaluated, and antibacterial activity was assessed by seeding a Streptococcus mutans strain (ATCC 25175) on the experimental polymeric surfaces. Cellular survival and osteodifferentiation were evaluated in epithelial (HaCat) and preosteoblast cells (MC3T3-E1).

RESULTS: The 0.001% DTWCNTG concentration yielded higher compressive strength, elastic modulus, flexural strength, flexural modulus, water sorption, and solubility than the control. The degree of conversion and color did not significantly change with a low amount of DTWCNTG incorporated into the polymer. Antibacterial activity significantly improved when tested on the 0.001% DTWCNTG discs. No groups showed cytotoxicity in a short-term analysis and adding DTWCNTG favored MC3T3-E1 mineralization over the control, particularly in the 0.001% formulation.

SIGNIFICANCE: The micro-addition of 0.001% DTWCNTG confers mechanical resistance, antimicrobial properties, and bioactivity to methacrylate-based polymers without significantly compromising color. Incorporating DTWCNTG improved dental composite properties and could be a biomodified material for minimally invasive procedures.}, } @article {pmid36251248, year = {2023}, author = {Aswathanarayan, JB and Rao, P and Hm, S and Gs, S and Rai, RV}, title = {Biofilm-Associated Infections in Chronic Wounds and Their Management.}, journal = {Advances in experimental medicine and biology}, volume = {1370}, number = {}, pages = {55-75}, pmid = {36251248}, issn = {0065-2598}, mesh = {Humans ; Ulcer ; *Anti-Infective Agents ; *Staphylococcal Infections ; Staphylococcus aureus ; Biofilms ; Pseudomonas aeruginosa/physiology ; *Wound Infection/therapy ; Anti-Bacterial Agents/therapeutic use ; }, abstract = {Chronic wounds including vascular ulcers, diabetic ulcers, pressure ulcers, and burn wounds show delayed progress through the healing process. Some of their common features are prolonged inflammation, persistent infection, and presence of biofilms resistant to antimicrobials and host immune response. Biofilm formation by opportunistic pathogens is a major problem in chronic wound management. Some of the commonly and traditionally used chronic wound management techniques are physical debridement and cleansing. In recent years, novel techniques based on anti-biofilm agents are explored to prevent biofilm-associated infections and facilitate wound healing. In this chapter, the role of biofilms formed by the ESKAPE pathogens (Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa) and Candida species in delayed wound healing have been discussed. The current and emerging techniques in the detection of biofilms for the management of wounds have been focused. The limitations of the existing therapeutics and novel wound management strategies have been deliberated.}, } @article {pmid36250857, year = {2022}, author = {Chen, A and Dellos-Nolan, S and Lu, Y and West, JS and Wozniak, DJ and Mitton-Fry, MJ}, title = {Dioxane-Linked Novel Bacterial Topoisomerase Inhibitors Exhibit Bactericidal Activity against Planktonic and Biofilm Staphylococcus aureus In Vitro.}, journal = {Microbiology spectrum}, volume = {10}, number = {6}, pages = {e0205622}, pmid = {36250857}, issn = {2165-0497}, support = {R21 AI148986/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; }, mesh = {Humans ; Staphylococcus aureus ; *Methicillin-Resistant Staphylococcus aureus ; Topoisomerase Inhibitors/pharmacology ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology/chemistry ; *Staphylococcal Infections/drug therapy/microbiology ; Biofilms ; Dioxanes/pharmacology ; }, abstract = {The development of novel treatments for Staphylococcus aureus infections remains a high priority worldwide. We previously reported compounds 0147 and 0186, novel bacterial topoisomerase inhibitors (NBTIs) with potent antibacterial activity against S. aureus, including methicillin-resistant S. aureus. Here, we further investigated the in vitro activity of 0147 and 0186 against S. aureus ATCC 29213. Both compounds demonstrated bactericidal activity against planktonic and biofilm S. aureus, which then translated into significant inhibition of biofilm formation. Combinations of NBTIs and glycopeptides yielded indifferent interactions against planktonic S. aureus, but several had synergistic effects against S. aureus biofilms. This work reinforces the potential of NBTIs as future therapeutics for S. aureus infections. IMPORTANCE The pathogen Staphylococcus aureus contributes substantially to infection-related mortality. Biofilms render bacteria more recalcitrant to antibacterial therapy. The manuscript describes the potent activity of a new class of antibacterial agents against both planktonic and biofilm populations of Staphylococcus aureus.}, } @article {pmid36249378, year = {2022}, author = {Lee, HW and Kharel, S and Loo, SCJ}, title = {Lipid-Coated Hybrid Nanoparticles for Enhanced Bacterial Biofilm Penetration and Antibiofilm Efficacy.}, journal = {ACS omega}, volume = {7}, number = {40}, pages = {35814-35824}, pmid = {36249378}, issn = {2470-1343}, abstract = {Up to 80% of all infections are biofilm-mediated and they are often challenging to treat as the underlying bacterial cells can become 100- to 1000-fold more tolerant toward antibiotics. Antibiotic-loaded nanoparticles have gained traction as a potential drug delivery system to treat biofilm infections. In particular, lipid-coated hybrid nanoparticles (LCHNPs) were investigated on their capability to deliver antibiotics into biofilms. In this study, LCHNPs composed of a poly(lactic-co-glycolic acid) (PLGA) core and dioleoyl-3-trimethylammonium propane (DOTAP) lipid shell were developed and loaded with vancomycin (Van). In vitro antibacterial and antibiofilm tests were performed to evaluate the antimicrobial efficacy of the LCHNPs. LCHNPs were successfully fabricated with high vancomycin encapsulation and loading efficiencies, and exhibited enhanced antibacterial effects against planktonic Staphylococcus aureus USA300 when compared against Free-Van and Van-PLGANPs. When used to treat USA300 biofilms, Van-LCHNPs eradicated up to 99.99% of the underlying biofilm cells, an effect which was not observed for Free-Van and Van-PLGANPs. Finally, we showed that by possessing a robust DOTAP shell, LCHNPs were able to penetrate deeply into the biofilms.}, } @article {pmid36248376, year = {2022}, author = {Citterio, F and Zanotto, E and Pellegrini, G and Annaratore, L and Barbui, AM and Dellavia, C and Baima, G and Romano, F and Aimetti, M}, title = {Comparison of Different Chemical and Mechanical Modalities for Implant Surface Decontamination: Activity against Biofilm and Influence on Cellular Regrowth-An In Vitro Study.}, journal = {Frontiers in surgery}, volume = {9}, number = {}, pages = {886559}, pmid = {36248376}, issn = {2296-875X}, abstract = {OBJECTIVES: The aim of this in vitro study was to compare the efficacy of chemical and mechanical methods for decontamination of titanium dental implant surfaces previously infected with polymicrobial biofilms in a model simulating a peri-implant defect. Furthermore, the effect of each decontamination protocol on MG-63 osteoblast-like cells morphology and adhesion to the treated implants was assessed.

BACKGROUND: Peri-implantitis is a growing issue in dentistry, and evidence about implant surface decontamination procedures is lacking and inconclusive.

METHODS: A total of 40 previously biofilm-contaminated implants were placed into a custom-made model simulating a peri-implant defect and randomly assigned to five treatment groups: (C) control (no treatment); (AW) air abrasion without any powder; (ESC) air abrasion with powder of erythritol, amorphous silica, and 0.3% chlorhexidine; (HBX) decontamination with a sulfonic/sulfuric acid solution in gel; and (HBX + ESC) a combination of HBX and ESC. Microbiological analysis was performed on five implants per treatment group, and the residual viable bacterial load measured in log 10 CFU/mL was counted for each bacterial strain and for the total number of colonies. The remaining three implants per group and three noncontaminated (NC) implants were used to assess surface biocompatibility using a scanning electron microscope and a backscattered electron microscope after seeding with MG-63 cells.

RESULTS: A significant decontaminant effect was achieved using HBX or HBX + ESC, while no differences were observed among other groups. The percentage of implant surface covered by adherent MG-63 cells was influenced by the treatment method. Progressive increases in covered surfaces were observed in groups C, AW, ESC, HBX, HBX + ESC, and NC.

CONCLUSIONS: A combination of mechanical and chemical decontamination may provide more predictable results than mechanical cleaning alone.}, } @article {pmid36248312, year = {2022}, author = {Özkul, G and Kehribar, EŞ and Ahan, RE and Köksaldı, İÇ and Özkul, A and Dinç, B and Aydoğan, S and Şeker, UÖŞ}, title = {A Genetically Engineered Biofilm Material for SARS-CoV-2 Capturing and Isolation.}, journal = {Advanced materials interfaces}, volume = {}, number = {}, pages = {2201126}, pmid = {36248312}, issn = {2196-7350}, abstract = {The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is continuously infecting people all around the world since its outbreak in 2019. Studies for numerous infection detection strategies are continuing. The sensitivity of detection methods is crucial to separate people with mild infections from people who are asymptomatic. In this sense, a strategy that would help to capture and isolate the SARS-CoV-2 virus prior to tests can be effective and beneficial. To this extent, genetically engineered biomaterials grounding from the biofilm protein of Escherichia coli are beneficial due to their robustness and adaptability to various application areas. Through functionalizing the E. coli biofilm protein, diverse properties can be attained such as enzyme display, nanoparticle production, and medical implant structures. Here, E. coli species are employed to express major curli protein CsgA and Griffithsin (GRFT) as fusion proteins, through a complex formation using SpyTag and SpyCatcher domains. In this study, a complex system with a CsgA scaffold harboring the affinity of GRFT against Spike protein to capture and isolate SARS-CoV-2 virus is successfully developed. It is shown that the hybrid recombinant protein can dramatically increase the sensitivity of currently available lateral flow assays for Sars-CoV-2 diagnostics.}, } @article {pmid36247508, year = {2022}, author = {Pourahmadi, M and Pourahmadi, K and Modaresi, F and Atashpour, S and Azad, A and Ranjbaran, A and Ghasemian, A}, title = {The Antibacterial and Anti-biofilm Traits of the Novel BMAP-27-Melittin Conjugated Peptide Nanoparticle Against Streptococcus mutans: Clinical Isolates from Oral Cavity.}, journal = {Iranian journal of pathology}, volume = {17}, number = {3}, pages = {294-302}, pmid = {36247508}, issn = {1735-5303}, abstract = {BACKGROUND & OBJECTIVE: The spread and development of drug-resistant bacterial strains has prompted the hunt for novel antibacterial polypeptides undergoing conformational changes to confer rapid bactericidal effects. The aim of this study was to evaluate the effect of novel BMAP27-Melittin conjugated peptide- nanoparticle (NP) against Streptococcus mutans as the primary pathogen from subgingival plaques.

METHODS: Sixty subgingival plaque samples were collected, and 39 S. mutans isolates were identified. The BMAP27-Melittin conjugated peptide was purchased from GenScript Company, USA. Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Biofilm Inhibitory Concentration (BIC), and Biofilm Eradication Concentration (BEC) of BMAP27-Melittin-NP were calculated using the microtiter method.

RESULTS: Thirty-nine infected subjects were reported, including 24 males and 15 females (P=0.299). MIC, MBC, BIC, and BEC of BMAP27-Melittin-NP against S. mutans were 1.8, 2.9, 2.1, and 3.8μg/mL, respectively. The mean MBC, BEC, and BIC values were significantly lower among clinical isolates than S. mutans ATCC 35688 standard strain (P=0.032, 0.001, and 0.001, respectively).

CONCLUSION: BMAP27-Melittin-NP demonstrated significant antibacterial and anti-biofilm effects against clinical isolates of S. mutans which can be considered a promising compound to prevent or treat dental caries and eradicate the oral infections.}, } @article {pmid36247507, year = {2022}, author = {Goodarzi, F and Hallajzadeh, M and Sholeh, M and Talebi, M and Pirhajati Mahabadi, V and Amirmozafari, N}, title = {Anti-biofilm Activity of a Lytic Phage Against Vancomycin-Resistant Enterococcus faecalis.}, journal = {Iranian journal of pathology}, volume = {17}, number = {3}, pages = {285-293}, pmid = {36247507}, issn = {1735-5303}, abstract = {BACKGROUND & OBJECTIVE: This study aims to isolate a lytic bacteriophage against planktonic Enterococcus faecalis V583 culture and evaluate its ability to disrupt and inhibit biofilm.

METHODS: An anti-E. faecalis phage was isolated from sewage and visualized by electron microscopy, the vB_EfsS_V583 (V583) host range was determined by spot test on 13 E. faecalis clinical strains. Inhibition and degradation experiments were designed to investigate the effect of phage on biofilm. In the inhibition and degradation assay, biofilms were formed in the presence and absence of phage, respectively. Finally, crystal violet method tested the effect of phage on biofilm.

RESULTS: Phage V583 belongs to the Siphoviridae family and can infect all E. faecalis strains. Antibacterial activity has been shown to degrade and inhibit biofilm produced by V583. The study results showed that phage v583 is more efficient in biofilm inhibition than biofilm degradation. In both assays, phage-treated wells' absorption is less than untreated wells. These results were confirmed by Colony-forming unit reduction in the treated biofilm.

CONCLUSION: The anti-biofilm activity showed that phage therapy using phage V583 might be an alternative tool to remove E. faecalis biofilms.}, } @article {pmid36246231, year = {2022}, author = {Lu, Y and Lei, L and Deng, Y and Zhang, H and Xia, M and Wei, X and Yang, Y and Hu, T}, title = {RNase III coding genes modulate the cross-kingdom biofilm of Streptococcus mutans and Candida albicans.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {957879}, pmid = {36246231}, issn = {1664-302X}, abstract = {Streptococcus mutans constantly coexists with Candida albicans in plaque biofilms of early childhood caries (ECC). The progression of ECC can be influenced by the interactions between S. mutans and C. albicans through exopolysaccharides (EPS). Our previous studies have shown that rnc, the gene encoding ribonuclease III (RNase III), is implicated in the cariogenicity of S. mutans by regulating EPS metabolism. The DCR1 gene in C. albicans encodes the sole functional RNase III and is capable of producing non-coding RNAs. However, whether rnc or DCR1 can regulate the structure or cariogenic virulence of the cross-kingdom biofilm of S. mutans and C. albicans is not yet well understood. By using gene disruption or overexpression assays, this study aims to investigate the roles of rnc and DCR1 in modulating the biological characteristics of dual-species biofilms of S. mutans and C. albicans and to reveal the molecular mechanism of regulation. The morphology, biomass, EPS content, and lactic acid production of the dual-species biofilm were assessed. Quantitative real-time polymerase chain reaction (qRT-PCR) and transcriptomic profiling were performed to unravel the alteration of C. albicans virulence. We found that both rnc and DCR1 could regulate the biological traits of cross-kingdom biofilms. The rnc gene prominently contributed to the formation of dual-species biofilms by positively modulating the extracellular polysaccharide synthesis, leading to increased biomass, biofilm roughness, and acid production. Changes in the microecological system probably impacted the virulence as well as polysaccharide or pyruvate metabolism pathways of C. albicans, which facilitated the assembly of a cariogenic cross-kingdom biofilm and the generation of an augmented acidic milieu. These results may provide an avenue for exploring new targets for the effective prevention and treatment of ECC.}, } @article {pmid36245096, year = {2022}, author = {Cometta, S and Jones, RT and Juárez-Saldivar, A and Donose, BC and Yasir, M and Bock, N and Dargaville, TR and Bertling, K and Brünig, M and Rakić, AD and Willcox, M and Hutmacher, DW}, title = {Melimine-Modified 3D-Printed Polycaprolactone Scaffolds for the Prevention of Biofilm-Related Biomaterial Infections.}, journal = {ACS nano}, volume = {16}, number = {10}, pages = {16497-16512}, pmid = {36245096}, issn = {1936-086X}, mesh = {Humans ; *Pseudomonas aeruginosa ; *Antimicrobial Cationic Peptides/chemistry ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; Coated Materials, Biocompatible/chemistry ; Bacteria ; Amino Acids ; Carbodiimides/pharmacology ; Printing, Three-Dimensional ; }, abstract = {Biomaterial-associated infections are one of the major causes of implant failure. These infections result from persistent bacteria that have adhered to the biomaterial surface before, during, or after surgery and have formed a biofilm on the implant's surface. It is estimated that 4 to 10% of implant surfaces are contaminated with bacteria; however, the infection rate can be as high as 30% in intensive care units in developed countries and as high as 45% in developing countries. To date, there is no clinical solution to prevent implant infection without relying on the use of high doses of antibiotics supplied systemically and/or removal of the infected device. In this study, melimine, a chimeric cationic peptide that has been tested in Phase I and II human clinical trials, was immobilized onto the surface of 3D-printed medical-grade polycaprolactone (mPCL) scaffolds via covalent binding and adsorption. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) spectra of melimine-treated surfaces confirmed immobilization of the peptide, as well as its homogeneous distribution throughout the scaffold surface. Amino acid analysis showed that melimine covalent and noncovalent immobilization resulted in a peptide density of ∼156 and ∼533 ng/cm[2], respectively. Furthermore, we demonstrated that the immobilization of melimine on mPCL scaffolds by 1-ethyl-3-[3-(dimethylamino)propyl] carbodiimide hydrochloride (EDC) coupling and noncovalent interactions resulted in a reduction of Staphylococcus aureus colonization by 78.7% and 76.0%, respectively, in comparison with the nonmodified control specimens. Particularly, the modified surfaces maintained their antibacterial properties for 3 days, which resulted in the inhibition of biofilm formation in vitro. This system offers a biomaterial strategy to effectively prevent biofilm-related infections on implant surfaces without relying on the use of prophylactic antibiotic treatment.}, } @article {pmid36244849, year = {2023}, author = {Hazarika, P and Chattopadhyay, I and Umpo, M and Choudhury, Y and Sharma, I}, title = {Studies on antimicrobial stress with reference to biofilm formation of faecal microbial communities from Apatani tribe of Arunachal Pradesh.}, journal = {Indian journal of medical microbiology}, volume = {43}, number = {}, pages = {1-7}, doi = {10.1016/j.ijmmb.2022.09.011}, pmid = {36244849}, issn = {1998-3646}, mesh = {Humans ; Phylogeny ; *Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology ; Enterococcus ; *Enterococcus faecium ; Escherichia coli ; Biofilms ; Feces/microbiology ; }, abstract = {PURPOSE: Antibiotic resistant bacteria have created serious health conditions worldwide, disseminating various infections to people and community along with direct clinical implications in therapeutic options.

METHODS: The present study analysed 20 samples from human faeces of Apatani tribe, Arunachal Pradesh, India. Biofilm assay, antimicrobial susceptibility tests and antimicrobial profiling were performed along with phylogenetic analysis.

RESULTS: Phenotypic screening indicated the presence of 21 aerobic isolates comprising Escherichia sp 42.8% (n ​= ​9), Citrobacter sp 9.52% (n ​= ​2), Klebsiella sp 23.8% (n ​= ​5) and Enterococcus sp 23.8% (n ​= ​5). Tetracycline, ciprofloxacin, ceftadizime, gentamicine, vancomycin and erythromycin were observed to highly dominate the biofilm producing bacteria. Antimicrobial activity of Escherichia sp, Citrobacter sp, Klebsiella sp, and Enterococcus sp inhibited the growth of at least one of the tested pathogens. Phylogenetic analysis revealed that antibiotic resistant Klebsiella sp belonged to Klebsiella pneumonia; Escherichia sp belonged to Escherichia fergusonii and Escherichia coli; Enterococcus sp belonged to Enterococcus faecium while Citrobacter sp belonged to Citrobacter freundii.

CONCLUSION: The present work shows that antibiotic resistant bacteria-Klebsiella sp, Enterococcus sp, Escherichia sp and Citrobacter sp were highly prevalent in the faecal microbial communities of Apatani tribe from Arunachal Pradesh. Presence of such antibiotic resistance and biofilm formation in faecal microbiota poses serious concerns regarding health and therapeutic options as this tribe mostly resides in remote vicinities of Arunachal Pradesh. Thus, exploring the mechanisms for dissemination of antibiotic resistance in this tribe helped us to identify key factors pertaining to the health of this tribe as well as their environment.}, } @article {pmid36244762, year = {2022}, author = {Morohoshi, T and Taniguchi, A and Sugawara, A and Suzuki, T and Sato, S}, title = {Effects of Marine Sand on the Microbial Degradation of Biodegradable Plastics in Seawater and Biofilm Communities that Formed on Plastic Surfaces.}, journal = {Microbes and environments}, volume = {37}, number = {4}, pages = {}, pmid = {36244762}, issn = {1347-4405}, mesh = {Bacteria/genetics/metabolism ; *Biodegradable Plastics/metabolism ; Biodegradation, Environmental ; Biofilms ; Caproates ; Sand ; Seawater/microbiology ; }, abstract = {Four types of biodegradable plastics were evaluated for their biodegradability in seawater collected at Ajigaura coast, Japan, in the presence or absence of marine sand. One of the plastics, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), showed a degree of biodegradation in a seawater sample, and the addition of marine sand markedly accelerated its biodegradation. The addition of marine sand did not affect the bacterial composition of the biofilm that formed on PHBH, and the family Rhodobacteraceae, which was predicted to contribute to the degradation of PHBH, was dominant in biofilm communities regardless of the addition of marine sand. Marine sand may serve as a bacterial source, resulting in the accelerated degradation of PHBH.}, } @article {pmid36244683, year = {2022}, author = {Sindelo, A and Nene, L and Nyokong, T}, title = {Photodynamic antimicrobial chemotherapy with asymmetrical cationic or neutral metallophthalocyanines conjugated to amino-functionalized zinc oxide nanoparticles (spherical or pyramidal) against planktonic and biofilm microbial cultures.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103160}, doi = {10.1016/j.pdpdt.2022.103160}, pmid = {36244683}, issn = {1873-1597}, mesh = {*Zinc Oxide/pharmacology ; Plankton ; Staphylococcus aureus ; Escherichia coli ; *Photochemotherapy/methods ; Biofilms ; Candida albicans ; Cations ; Indoles/pharmacology/chemistry ; *Anti-Infective Agents ; *Staphylococcal Infections ; Anti-Bacterial Agents/pharmacology/chemistry ; }, abstract = {The synthesis and characterization of neutral zinc and indium substituted mercaptobenzothiazole substituted phthalocyanines (Pcs) and their respective cationic derivatives are presented. The phthalocyanines were further covalently linked to two differently shaped amino-functionalized ZnO nanoparticles (ZnONPs): namely nanospheres (NH2-ZnONSp), and nanopyramids (NH2-ZnONPy), to form corresponding nanoconjugates. The photophysicochemical properties of each nanocomposite were determined, and the Pc-ZnONPs produced high singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity was determined using planktonic and biofilm cells of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Candida albicans (C. albicans). The conjugates of the cationic Pc derivatives with ZnONPy produced the highest log reduction values (∼ 8 and above) with the complete elimination of all planktonic cells at 0.45 kJ/cm[2] for S. aureus and at 0.9 kJ/cm[2] for E. coli, and C. albicans. For biofilms log reduction values >3 for both S. aureus and E. coli were obtained. The conjugates of the cationic Pc derivatives with NH2-ZnONPy showed great potential in eradicating mixed microbial biofilms.}, } @article {pmid36244678, year = {2022}, author = {Tonon, CC and Panariello, B and Chorilli, M and Spolidorio, DMP and Duarte, S}, title = {Effect of curcumin-loaded photoactivatable polymeric nanoparticle on peri-implantitis-related biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103150}, doi = {10.1016/j.pdpdt.2022.103150}, pmid = {36244678}, issn = {1873-1597}, mesh = {Humans ; *Curcumin/pharmacology ; *Peri-Implantitis/drug therapy ; *Photochemotherapy/methods ; Biofilms ; Photosensitizing Agents/pharmacology ; Polymers/pharmacology ; }, abstract = {Curcumin has been used as a photosensitizer (PS) for antimicrobial photodynamic chemotherapy (PACT). However, its low solubility, instability, and poor bioavailability challenge its in vivo application. This study aimed to synthesize curcumin-loaded polymeric nanoparticles (curcumin-NP) and determine their antimicrobial and cytotoxic effects. Nanoparticles (NP) were synthesized using polycaprolactone (PCL) as a polymer by the nanoprecipitation method. Curcumin-NP was characterized by particle size, polydispersity index and zeta potential, scanning electron microscopy, and curcumin encapsulation efficiency (EE). Curcumin-NP was compared to free curcumin solubilized in 10% DMSO as photosensitizers for PACT in single and multispecies Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus oralis biofilms. Chlorhexidine 0.12% (CHX) and ultrapure water were used as positive and negative controls. The cytotoxic effect of curcumin-NP was evaluated on human periodontal ligament fibroblast cells (HPLF). Data were analyzed by ANOVA (α=0.05). Curcumin-NP exhibited homogeneity and stability in solution, small particle size, and 67.5% EE of curcumin. Curcumin-NP presented reduced antibiofilm activity at 500 µg/ml, although in planktonic cultures it showed inhibitory and bactericidal effect. Curcumin-NP and curcumin with and without photoactivation were not cytotoxic to HPLF cells. Curcumin-NP has antimicrobial and antibiofilm properties, with better effects when associated with blue light, being a promising therapy for preventing and treating peri-implant diseases.}, } @article {pmid36244605, year = {2022}, author = {Li, C and Wang, JH and Yu, C and Zhang, JT and Chi, ZY and Zhang, Q}, title = {Growth-promoting effects of phytohormones on capillary-driven attached Chlorella sp. biofilm.}, journal = {Bioresource technology}, volume = {364}, number = {}, pages = {128117}, doi = {10.1016/j.biortech.2022.128117}, pmid = {36244605}, issn = {1873-2976}, abstract = {Using low strength wastewater for microalgae cultivation is challenged by slow growth and biomass harvesting issue in suspended systems, and growth-promoting effects of phytohormones at currently recommended dosages could neither obtain high enough biomass concentrations nor economic feasibility. This study aims to solve the issues of slow growth, biomass harvest, and phytohormone costs altogether by supplementing low dosage phytohormones in an improved capillary-driven attached cultivation device. The device displayed nutrients-condensing properties, and dosages of indole acetic acid (IAA), 6-benzylaminopurine (6-BA), and salicylic acid (SA) for highest microalgal growth were respectively 10[-6] M, 10[-6] M, and 10[-7] M, being at least one order of magnitude lower than in suspended cultures. SA was most effective in growth-promoting (up to 7.0 g/m[2] biomass density) and nutrients uptake (up to 98.6 % from the bulk environment), while IAA was most effective in antioxidative defenses. These results provided new insights in cost-effective and harvesting-convenient microalgae production.}, } @article {pmid36244602, year = {2022}, author = {Zhu, Q and Hu, J and Liu, B and Liang, S and Xiao, K and Yu, W and Yuan, S and Yang, J and Hou, H}, title = {Potassium channel blocker selectively enriched Geobacter from mixed-cultured electroactive biofilm: Insights from microbial community, functional prediction and gene expressions.}, journal = {Bioresource technology}, volume = {}, number = {}, pages = {128109}, doi = {10.1016/j.biortech.2022.128109}, pmid = {36244602}, issn = {1873-2976}, abstract = {This study investigated the effects of electrical signaling disruption induced by adding tetraethylammonium (TEA, a potassium channel blocker) on the formation of mixed-cultured electroactive biofilms, especially the relative abundance of Geobacter over time. Results showed that TEA addition decelerated the biofilm formation, but selectively enriched Geobacter over time (45.8% on Day 32, 67.7% on Day 60 and 78.1% on Day 90), thus resulting in higher final extracellular electron transfer (EET) efficiency. Redundancy analysis (RDA) confirmed that TEA and operation time were significant factors for the selective enrichment of Geobacter. Moreover, increase in cellular processes and signal processing by PICRUSt analysis indicated adaptive responses of electrogenic biofilms to electrical signaling disruption. Furthermore, qRT-PCR indicated the compensatory roles of key cytochromes and pilA in electrochemical communication, which induced Geobacter enrichment. This work provided a broader understanding of electroactive biofilm regulation and potential applications for electricity generation and biosensor in the future.}, } @article {pmid36243954, year = {2022}, author = {Wei, T and Zheng, N and Zheng, H and Chen, Y and Hong, P and Liu, W and Liu, M}, title = {Proteomic Perspective of Azole Resistance in Aspergillus fumigatus Biofilm Extracellular Matrix in Response to Itraconazole.}, journal = {Medical mycology}, volume = {}, number = {}, pages = {}, doi = {10.1093/mmy/myac084}, pmid = {36243954}, issn = {1460-2709}, abstract = {Azole-resistant Aspergillus fumigatus makes a major challenge to the chemotherapy for invasive aspergillosis, whereas cyp51A gene mutation is the most dominant mechanism for azole resistance. Moreover, biofilm contributes to drug resistance for A. fumigatus, and extracellular matrix (ECM) is essential to protect live cells from antifungal drugs. Therefore, we performed a comparative proteomic study on the biofilm ECM of both the wild-type and azole-resistant strains of A. fumigatus under azole pressure. In total, 2377 proteins were identified, of which 480 and 604 proteins with differential expression were obtained from the wild-type and azole-resistant A. fumigatus in exposure to itraconazole respectively (fold change > 2 or < 0.5, P-value < 0.05). We found that a high proportion of regulated proteins were located in cytoplasm, nucleus, and mitochondria. Meanwhile, GO and KEGG analyses revealed that metabolic process and ribosome pathway were significantly enriched. Particularly, differentially expressed proteins in response to azole pressure of both the wild-type and resistant strains were further analyzed. Our results indicated that these changes in biofilm ECM proteins were related to ergosterol synthesis, oxidative stress, efflux pumps, DNA repair, DNA replication, and transcription.}, } @article {pmid36243882, year = {2022}, author = {Leggett, A and Li, DW and Bruschweiler-Li, L and Sullivan, A and Stoodley, P and Brüschweiler, R}, title = {Differential metabolism between biofilm and suspended Pseudomonas aeruginosa cultures in bovine synovial fluid by 2D NMR-based metabolomics.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {17317}, pmid = {36243882}, issn = {2045-2322}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R35 GM139482/GM/NIGMS NIH HHS/United States ; }, mesh = {Alanine/metabolism ; Animals ; Anti-Bacterial Agents/metabolism ; Biofilms ; Cattle ; Choline/metabolism ; Creatine/metabolism ; Glutathione/metabolism ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/physiology ; Quality of Life ; Synovial Fluid ; }, abstract = {Total joint arthroplasty is a common surgical procedure resulting in improved quality of life; however, a leading cause of surgery failure is infection. Periprosthetic joint infections often involve biofilms, making treatment challenging. The metabolic state of pathogens in the joint space and mechanism of their tolerance to antibiotics and host defenses are not well understood. Thus, there is a critical need for increased understanding of the physiological state of pathogens in the joint space for development of improved treatment strategies toward better patient outcomes. Here, we present a quantitative, untargeted NMR-based metabolomics strategy for Pseudomonas aeruginosa suspended culture and biofilm phenotypes grown in bovine synovial fluid as a model system. Significant differences in metabolic pathways were found between the suspended culture and biofilm phenotypes including creatine, glutathione, alanine, and choline metabolism and the tricarboxylic acid cycle. We also identified 21 unique metabolites with the presence of P. aeruginosa in synovial fluid and one uniquely present with the biofilm phenotype in synovial fluid. If translatable in vivo, these unique metabolite and pathway differences have the potential for further development to serve as targets for P. aeruginosa and biofilm control in synovial fluid.}, } @article {pmid36243235, year = {2022}, author = {Baig, MMFA and Fatima, A and Gao, X and Farid, A and Ajmal Khan, M and Zia, AW and Wu, H}, title = {Disrupting biofilm and eradicating bacteria by Ag-Fe3O4@MoS2 MNPs nanocomposite carrying enzyme and antibiotics.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {352}, number = {}, pages = {98-120}, doi = {10.1016/j.jconrel.2022.10.009}, pmid = {36243235}, issn = {1873-4995}, mesh = {*Anti-Bacterial Agents/pharmacology ; Molybdenum ; Biofilms ; *Nanocomposites ; Bacteria ; Vancomycin ; Deoxyribonucleases ; }, abstract = {In this study, novel multilayered magnetic nanoparticles (ML-MNPs) loaded with DNase and/or vancomycin (Vanc) were fabricated for eliminating multispecies biofilms. Iron-oxide MNPs (IO-core) (500-800 nm) were synthesized via co-precipitation; further, the IO-core was coated with heavy-metal-based layers (Ag and MoS2 NPs) using solvent evaporation. DNase and Vanc were loaded onto the outermost layer of the ML-MNP formed by nanoporous MoS2 NPs through physical deposition and adsorption. The biofilms of S. mutans or E. faecalis (or both) were formed in a brain-heart-infusion broth (BHI) for 3 days, followed by treatment with ML-MNPs for 24 h. The results revealed that coatings of Ag (200 nm) and ultrasmall MoS2 (20 nm) were assembled as outer layers of ML-MNPs successfully, and they formed Ag-Fe3O4@MoS2 MNPs (3-5 μm). The DNase-Vanc-loaded MNPs caused nanochannels digging and resulted in the enhanced penetration of MNPs towards the bottom layers of biofilm, which resulted in a decrease in the thickness of the 72-h biofilm from 48 to 58 μm to 0-4 μm. The sustained release of Vanc caused a synergistic bacterial killing up to 96%-100%. The heavy-metal-based layers of MNPs act as nanozymes to interfere with bacterial metabolism and proliferation, which adversely affects biofilm integrity. Further, loading DNase/Vanc onto the nanoporous-MoS2-layer of ML-MNPs promoted nanochannel creation through the biofilm. Therefore, DNase-and Vanc-loaded ML-MNPs exhibited potent effects on biofilm disruption and bacterial killing.}, } @article {pmid36243231, year = {2022}, author = {Jacobo, U and Kopel, J and Reed, J and Patel, S and Jain, S and Tran, P and Abidi, N and Bergfeld, N and Reid, T}, title = {The efficacy of organo-selenium conjugated cellulose polymer dressing to inhibit Candida albicans biofilm formation.}, journal = {Journal of microbiological methods}, volume = {202}, number = {}, pages = {106598}, doi = {10.1016/j.mimet.2022.106598}, pmid = {36243231}, issn = {1872-8359}, mesh = {Humans ; *Candida albicans ; *Selenium/pharmacology ; Cellulose/pharmacology ; Polymers ; Antifungal Agents/pharmacology ; Biofilms ; Bandages ; }, abstract = {Selenium covalently bonded to cellulose can catalyze the formation of superoxide radicals. Candida albicans, colonizes epithelial surfaces and can be a fatal infection in immunocompromised people. In this study, we demonstrated the ability of organo-selenium, covalently attached to cotton textile dressings to kill C. albicans biofilms.}, } @article {pmid36240916, year = {2023}, author = {Ma, T and Cheng, C and Xing, L and Sun, Y and Wu, G}, title = {Quorum sensing responses of r-/K-strategists Nitrospira in continuous flow and sequencing batch nitrifying biofilm reactors.}, journal = {The Science of the total environment}, volume = {857}, number = {Pt 1}, pages = {159328}, doi = {10.1016/j.scitotenv.2022.159328}, pmid = {36240916}, issn = {1879-1026}, mesh = {*Quorum Sensing ; *Nitrites/metabolism ; Biofilms ; Nitrification ; Acyl-Butyrolactones/metabolism ; Bacteria/metabolism ; }, abstract = {A better understanding of r-/K-strategists nitrifiers will help to balance the design and operation of bioprocesses for efficient pollution removal from wastewater. The objectives of study were to investigate the nitrite oxidation biokinetics, biofilm property, microbial community and quorum sensing (QS) of nitrifying biofilm in a continuously flow reactor (CFR) and a sequencing batch reactor (SBR). Results showed that nitrite-oxidizing bacteria were estimated to have a nitrite half saturation constant of 76.23 and 224.73 μM in CFR and SBR, respectively. High-throughput and metagenomic sequencing results showed that Nitrospira and Candidatus Nitrospira defluvii were the dominated nitrite-oxidizing taxa performing nitrite oxidation in both reactors. Nitrifying biofilm developed in CFR and SBR showed obviously different properties. Biofilm in SBR had an obviously higher ratio of polysaccharide and protein in extracellular polymeric substances, and higher thickness than in CFR. Metagenomics and chemical analysis revealed various types of acyl-homoserine lactone (AHL) circuit genes (e.g., luxI, lasI, hdtS) and four types of AHL signaling substances (e.g., C6-HSL, C8-HSL, C10-HSL and 3-oxo-C10-HSL) in nitrifying biofilm. The concentrations of these AHLs in biomass and water phases were obviously higher in SBR than that in CFR. Together, AHLs-based QS might affect the formation of nitrifying biofilm and thus contribute to the different biokinetics of Nitrospira in CFR and SBR. Our insights may reveal the molecular mechanism of Nitrospira for different biokinetics, and indicate the AHL association with Nitrospira adaptation to various conditions.}, } @article {pmid36240800, year = {2022}, author = {Cogo, A and Bignozzi, AC and Hermans, MH and Quint, BJ and Snels, JP and Schultz, G}, title = {A desiccation compound as a biofilm- and necrosis-removing agent: a case series.}, journal = {Journal of wound care}, volume = {31}, number = {10}, pages = {816-822}, doi = {10.12968/jowc.2022.31.10.816}, pmid = {36240800}, issn = {0969-0700}, mesh = {Biofilms ; Desiccation ; *Diabetic Foot/therapy ; Humans ; Necrosis ; Retrospective Studies ; Treatment Outcome ; *Varicose Ulcer/therapy ; }, abstract = {OBJECTIVE: A new compound, Debrichem (DEBx Medical BV, the Netherlands), a topical desiccation agent (TDA), is an active gel that contains an acidic species with a potent hygroscopic action. When in contact with microorganisms and necrosis, rapid desiccation and carbonisation of the proteins in these microorganisms, as well as of the extracellular matrix of biofilms and necrosis, occurs. The resulting 'precipitate' rapidly dislodges from the wound bed, resulting in a clean wound which granulates, which is a prerequisite for healing by secondary intention.

METHOD: In a retrospective study, a series of mostly large and hard-to-heal lesions of different aetiologies were treated with a one-time application of the TDA, followed by weekly dressing changes.

RESULTS: Of the total of 54 lesions included in this case series, 22 were diagnosed as venous leg ulcers (VLUs), 20 as diabetic foot ulcers (DFUs), nine as post-traumatic, hard-to-heal lesions, two as vascular ulcers and one as an ischaemic ulcer. All of the VLUs, 75% of the DFUs and all of the other lesions reached complete granulation.

CONCLUSION: The use of a TDA may contribute to the consistent, fast and easy removal of both biofilms and necrosis, and hence to wound healing.}, } @article {pmid36240659, year = {2022}, author = {Pourhajibagher, M and Bazarjani, F and Bahador, A}, title = {In silico and in vitro insights into the prediction and analysis of natural photosensitive compounds targeting Acinetobacter baumannii biofilm-associated protein.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103134}, doi = {10.1016/j.pdpdt.2022.103134}, pmid = {36240659}, issn = {1873-1597}, mesh = {*Acinetobacter baumannii ; *Photochemotherapy/methods ; Molecular Docking Simulation ; Biofilms ; Photosensitizing Agents/pharmacology ; *Curcumin/pharmacology ; Anti-Bacterial Agents/pharmacology ; }, abstract = {BACKGROUND: The spread of Acinetobacter baumannii strains has become a global concern due to its extensive antibiotic resistance and biofilm formation. To overcome it, new antimicrobial strategies have been needed. Among them, antimicrobial photodynamic therapy (aPDT) is an efficient approach against various microorganisms. This study was focused on the use of curcumin (Cur) and quercetin (Qct) as natural photosensitive compounds to improve the activity of aPDT against A. baumannii biofilm-associated protein (Bap).

MATERIALS AND METHODS: In this in silico and in vitro study, after determining drug-likeness property, ADME/Toxicity profile, and pharmacological activity of Cur and Qct, virtual screening and molecular docking were assessed to determine the potential binding modes of Cur and Qct to Bap. Then, the anti-biofilm potential of natural photosensitizers-mediated aPDT against A. baumannii was evaluated after the determination of minimum inhibitory concentration (MIC). Subsequently, reverse transcription-quantitative real-time PCR (RT-qPCR) was used to exhibit the anti-virulent effect of aPDT against the gene involved in the biofilm formation of A. baumannii RESULTS: Cur and Qct showed almost similar pharmacokinetic and pharmacodynamics properties. These natural photosensitizers obeyed all the criteria of Lipinski's rule of five principles. According to the molecular docking analysis of protein-ligand complexes, Qct and Cur with a high affinity for Bap showed binding affinity of -6.34 and -6.98 kcal/mol, respectively. According to the findings, aPDT using 4 ×, and 8 × MIC of Cur and Qct could significantly reduce A. baumannii growth in biofilm structures in comparison with the control group (P < 0.05). Also, a significant downregulation by 3.7-, and 5.2-fold in gene expression of bap was observed after treatment with sub-MIC doses of Cur- and Qct-mediated aPDT, respectively (P < 0.05).

CONCLUSIONS: In summary, the in silico analysis showed that Cur and Qct had strong binding affinity with Bap as a stable protein of A. baumannii. Furthermore, in vitro results displayed that targeted aPDT based on these natural photosensitizers can be considered a treatment against A. baumannii infections by reducing the growth of microbial biofilm and reducing the expression of bap as a gene involved in A. baumannii biofilm formation.}, } @article {pmid36240313, year = {2022}, author = {Freyschmidt, A and Beier, M}, title = {Model-based identification and testing of appropriate strategies to minimize N2O emissions from biofilm deammonification.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {7}, pages = {1810-1820}, doi = {10.2166/wst.2022.307}, pmid = {36240313}, issn = {0273-1223}, mesh = {*Ammonium Compounds ; Bacteria ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Nitrites ; Nitrous Oxide ; Oxidation-Reduction ; Oxygen ; }, abstract = {Based on a one-year pilot plant operation of a two-step biofilm nitritation-anammox pilot plant, N2O mitigation strategies were identified by applying a newly developed biofilm modeling approach. Due to adapted plant operation, the N2O emission could be diminished by 75% (8.8% → 2.3% of NH4-Noxidized_AOB). The results (measurement and simulation) confirm the huge importance of denitrification as an N2O source or N2O sink, depending on the boundary conditions. A significant reduction of N2O emissions could only be achieved with a one-step deammonification system, which is related to low nitrite and HNO2 concentrations. Increased oxygen concentrations in the bulk phase are not related to decreased emissions. N2O formation by ammonium-oxidizing bacteria (AOB) just shifts deeper into the biofilm; zones with low oxygen concentrations are not avoidable in biofilm systems. Low oxygen concentrations in the bulk phase, however, result in a reduction of the total net N2O formation due to increased activity of heterotrophic bacteria directly at the source of N2O formation (outer biofilm layer). For the model-based identification of mitigation strategies, the standard modeling approaches for biofilms were expanded by including the factor-based N2O formation and emission approach. The new model 'Biofilm/N2OISAH' was successfully validated using data from pilot-scale measurement campaigns. Altogether, the investigation confirms that the employed digital model can strongly support the development of N2O mitigation strategies without the need for specialized measurement inside the biofilm.}, } @article {pmid36239263, year = {2022}, author = {Zhu, W and Mei, J and Zhang, X and Zhou, J and Xu, D and Su, Z and Fang, S and Wang, J and Zhang, X and Zhu, C}, title = {Photothermal Nanozyme-Based Microneedle Patch against Refractory Bacterial Biofilm Infection via Iron-Actuated Janus Ion Therapy.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {34}, number = {51}, pages = {e2207961}, doi = {10.1002/adma.202207961}, pmid = {36239263}, issn = {1521-4095}, support = {81974324//National Natural Science Foundation of China/ ; 81802181//National Natural Science Foundation of China/ ; 81871788//National Natural Science Foundation of China/ ; 82202672//National Natural Science Foundation of China/ ; WK9110000152//Fundamental Research Funds for the Central Universities/ ; WK9110000173//Fundamental Research Funds for the Central Universities/ ; ynyq202202//Excellent Youth Training Program of Shanghai Jiao Tong University Affiliated Shanghai Sixth People's Hospital/ ; 201904a07020097//Anhui Provincial Key Research and Development Plan/ ; }, mesh = {Humans ; Drug Delivery Systems ; *Bacterial Infections/prevention & control/drug therapy ; *Nanoparticles/therapeutic use ; Iron ; Biofilms ; Anti-Bacterial Agents/pharmacology/therapeutic use ; }, abstract = {Owing to high antibiotic resistance and thermotolerance, bacterial biofilm infections (BBIs) are refractory to elimination. Iron is essential for bacterial growth and metabolism, and bacteria can thus accumulate iron from surrounding cells to maintain biofilm formation and survival. Consequently, iron deficiency in the biofilm microenvironment (BME) leads to the functional failure of innate immune cells. Herein, a novel antibiofilm strategy of iron-actuated Janus ion therapy (IJIT) is proposed to regulate iron metabolism in both bacterial biofilm and immune cells. A BME-responsive photothermal microneedle patch (FGO@MN) is synthesized by the growth of Fe3 O4 nanoparticles on graphene oxide nanosheets and then encapsulated in methacrylated hyaluronic acid needle tips. The catalytic product of ·OH by FGO@MN in BME disrupts the bacterial heat-shock proteins, coercing biofilm thermal sensitization. As synergistic mild photothermal treatment triggers iron uptake, the intracellular iron overload further induces ferroptosis-like death. Moreover, iron-nourished neutrophils around BME can be rejuvenated for reactivating the suppressed antibiofilm function. Thus, more than 95% BBIs elimination can be achieved by combining heat stress-triggered iron interference with iron-nutrient immune reactivation. Furthermore, in vivo experiments validate the scavenging of refractory BBI after 15 days, suggesting the promising perspective of IJIT in future clinical application.}, } @article {pmid36234690, year = {2022}, author = {Velázquez-Carriles, C and Macías-Rodríguez, ME and Ramírez-Alvarado, O and Corona-González, RI and Macías-Lamas, A and García-Vera, I and Cavazos-Garduño, A and Villagrán, Z and Silva-Jara, JM}, title = {Nanohybrid of Thymol and 2D Simonkolleite Enhances Inhibition of Bacterial Growth, Biofilm Formation, and Free Radicals.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {19}, pages = {}, pmid = {36234690}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/pharmacology ; *Antioxidants/pharmacology ; Biofilms ; Free Radicals ; Microbial Sensitivity Tests ; *Thymol/pharmacology ; Zinc ; }, abstract = {Due to the current concerns against opportunistic pathogens and the challenge of antimicrobial resistance worldwide, alternatives to control pathogen growth are required. In this sense, this work offers a new nanohybrid composed of zinc-layered hydroxide salt (Simonkolleite) and thymol for preventing bacterial growth. Materials were characterized with XRD diffraction, FTIR and UV-Vis spectra, SEM microscopy, and dynamic light scattering. It was confirmed that the Simonkolleite structure was obtained, and thymol was adsorbed on the hydroxide in a web-like manner, with a concentration of 0.863 mg thymol/mg of ZnLHS. Absorption kinetics was described with non-linear models, and a pseudo-second-order equation was the best fit. The antibacterial test was conducted against Escherichia coli O157:H7 and Staphylococcus aureus strains, producing inhibition halos of 21 and 24 mm, respectively, with a 10 mg/mL solution of thymol-ZnLHS. Moreover, biofilm formation of Pseudomonas aeruginosa inhibition was tested, with over 90% inhibition. Nanohybrids exhibited antioxidant activity with ABTS and DPPH evaluations, confirming the presence of the biomolecule in the inorganic matrix. These results can be used to develop a thymol protection vehicle for applications in food, pharmaceutics, odontology, or biomedical industries.}, } @article {pmid36234586, year = {2022}, author = {Haque, S and Faidah, H and Ashgar, SS and Abujamel, TS and Mokhtar, JA and Almuhayawi, MS and Harakeh, S and Singh, R and Srivastava, N and Gupta, VK}, title = {Green Synthesis of Zn(OH)2/ZnO-Based Bionanocomposite using Pomegranate Peels and Its Application in the Degradation of Bacterial Biofilm.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {19}, pages = {}, pmid = {36234586}, issn = {2079-4991}, abstract = {The ability and potency of bacterial species to form biofilms, which show antibiotic resistance thereby avoiding antibiotic surfaces, is a major cause of prolonged infections. Various advanced approaches have been employed to prevent or damage bacterial biofilms, formed by a variety of bacterial strains, to help prevent the associated infectious disease. In this context, zinc-based nanostructures have been recognized as a potential antibiotic agent against a broad spectrum of bacterial communities. As a result, a sustainable and green synthesis method was adapted in the present study to synthesize a Zn(OH)2/ZnO-based bionanocomposite, in which aqueous extracts of waste pomegranate peels (Punica granatum) were employed as a natural bioreducing agent to prepare the bionanocomposite at room temperature. Furthermore, FT-IR, XRD, DLS, UV-Visible, PL spectroscopy, FE-SEM, and TEM were used to characterize the green route synthesized a Zn(OH)2/ZnO bionanocomposite. The average crystallite size was determined using the Scherrer relation to be 38 nm, and the DLS results indicated that the Zn(OH)2/ZnO bionanocomposite had a hydrodynamic size of 170 nm. On the other hand, optical properties investigated through UV-Vis and PL spectroscopy explored the energy bandgap between 2.80 and 4.46 eV, corresponding to the three absorption edges, and it covered the blue spectrum when the sample was excited at 370 nm. Furthermore, the impact of this green route synthesized a Zn(OH)2/ZnO bionanocomposite on the biofilm degradation efficiency of the pathogenic bacterial strain Bacillus subtilis PF_1 using the Congored method was investigated. The Congored assay clearly explored the biofilm degradation efficiency in the presence of a 50 mg/mL and 75 mg/mL concentration of the Zn(OH)2/ZnO bionanocomposite against the bacterial strain Bacillus subtilis PF_1 grown for 24 h. This study can be further applied to the preparation of bionanocomposites following a low-cost green synthesis approach, and thus prepared nanostructures can be exploited as advanced antimicrobial agents, which could be of great interest to prevent various infectious diseases.}, } @article {pmid36234069, year = {2022}, author = {Kamimura, R and Kanematsu, H and Ogawa, A and Kogo, T and Miura, H and Kawai, R and Hirai, N and Kato, T and Yoshitake, M and Barry, DM}, title = {Quantitative Analyses of Biofilm by Using Crystal Violet Staining and Optical Reflection.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {19}, pages = {}, pmid = {36234069}, issn = {1996-1944}, support = {21K12739//JSPS Kakenhi/ ; }, abstract = {Biofilms have caused many problems, not only in the industrial fields, but also in our daily lives. Therefore, it is important for us to control them by evaluating them properly. There are many instrumental analytical methods available for evaluating formed biofilm qualitatively. These methods include the use of Raman spectroscopy and various microscopes (optical microscopes, confocal laser microscopes, scanning electron microscopes, transmission electron microscopes, atomic force microscopes, etc.). On the other hand, there are some biological methods, such as staining, gene analyses, etc. From the practical viewpoint, staining methods seem to be the best due to various reasons. Therefore, we focused on the staining method that used a crystal violet solution. In the previous study, we devised an evaluation process for biofilms using a color meter to analyze the various staining situations. However, this method was complicated and expensive for practical engineers. For this experiment, we investigated the process of using regular photos that were quantified without any instruments except for digitized cameras. Digitized cameras were used to compare the results. As a result, we confirmed that the absolute values were different for both cases, respectively. However, the tendency of changes was the same. Therefore, we plan to utilize the changes before and after biofilm formation as indicators for the future.}, } @article {pmid36233727, year = {2022}, author = {Thanetchaloempong, W and Koontongkaew, S and Utispan, K}, title = {Fixed Orthodontic Treatment Increases Cariogenicity and Virulence Gene Expression in Dental Biofilm.}, journal = {Journal of clinical medicine}, volume = {11}, number = {19}, pages = {}, pmid = {36233727}, issn = {2077-0383}, support = {WUICD- C2020//Walailak University, International College of Dentistry/ ; }, abstract = {Background: Dental caries commonly occurs during orthodontic treatment because fixed appliances can impede effective oral hygiene practices. This study investigated the effects of fixed orthodontic treatment on dental biofilm maturity and virulence gene (gtfB, ldh, brpA, spaP, luxS, and gbpB) expression. Methods: Dental biofilms and virulence gene expression were determined in 24 orthodontic patients before and after treatment of ≥6 months. A three-tone disclosing gel was used to stain dental biofilm and assess its maturity by its color change—pink (new dental biofilm), purple (mature dental biofilm), and light blue (cariogenic dental biofilm). Gene expression levels were determined using real-time PCR. Results: After fixed orthodontic appliance insertion, the percentage of new dental biofilm decreased, whereas that of cariogenic dental biofilm significantly increased (p < 0.05). There was no significant difference in the percentage of mature dental biofilm (p > 0.05). Fixed orthodontic appliances increased gtfB, ldh, brpA, and gbpB gene expression above 1.5-fold in dental biofilm. In contrast, there was no change in spaP or luxS gene expression after treatment. Conclusions: Fixed orthodontic appliance insertion induced ecological changes and cariogenic virulence gene expression in dental biofilm.}, } @article {pmid36233328, year = {2022}, author = {Pérez-Tanoira, R and Fernández-Arias, M and Potel, C and Carballo-Fernández, R and Pérez-Castro, S and Boutinguiza, M and Górgolas, M and Lusquiños, F and Pou, J}, title = {Silver Nanoparticles Produced by Laser Ablation and Re-Irradiation Are Effective Preventing Peri-Implantitis Multispecies Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {23}, number = {19}, pages = {}, pmid = {36233328}, issn = {1422-0067}, support = {EAPA_151/2016 Interreg Atlantic Area//EU research project Bluehuman/ ; PID2020-117900RB-I00 (MCI/AEI/FEDER, UE), EQC2018-004315-P (AEI/FEDER UE)//Government of Spain/ ; ED431C 2019/23//Xunta de Galicia/ ; Margarita Salas Postdoc Fellowship Program, M. Fernández Arias//University of Vigo/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Dental Implants ; Humans ; *Laser Therapy ; *Metal Nanoparticles ; *Peri-Implantitis/prevention & control ; Porphyromonas gingivalis ; *Re-Irradiation ; Silver/pharmacology ; Staphylococcus aureus ; Suspensions ; Titanium/chemistry/pharmacology ; Water/pharmacology ; }, abstract = {Implant-associated infection due to biofilm formation is a growing problem. Given that silver nanoparticles (Ag-NPs) have shown antibacterial effects, our goal is to study their effect against multispecies biofilm involved in the development of peri-implantitis. To this purpose, Ag-NPs were synthesized by laser ablation in de-ionized water using two different lasers, leading to the production of colloidal suspensions. Subsequently, part of each suspension was subjected to irradiation one and three times with the same laser source with which it was obtained. Ag-NPs were immobilized on the surface of titanium discs and the resultant materials were compared with unmodified titanium coupons. Nanoparticles were physico-chemically analysed to determine their shape, crystallinity, chemical composition, and mean diameter. The materials were incubated for 90 min or 48 h, to evaluate bacterial adhesion or biofilm formation respectively with Staphylococcus aureus or oral mixed bacterial flora composed of Streptococcus oralis, Actinomyces naeslundii, Veionella dispar, and Porphyromonas gingivalis. Ag-NPs help prevent the formation of biofilms both by S. aureus and by mixed oral bacterial flora. Nanoparticles re-irradiated three times showed the biggest antimicrobial effects. Modifying dental implants in this way could prevent the development of peri-implantitis.}, } @article {pmid36232864, year = {2022}, author = {Paleczny, J and Brożyna, M and Dudek-Wicher, R and Dydak, K and Oleksy-Wawrzyniak, M and Madziała, M and Bartoszewicz, M and Junka, A}, title = {The Medium Composition Impacts Staphylococcus aureus Biofilm Formation and Susceptibility to Antibiotics Applied in the Treatment of Bone Infections.}, journal = {International journal of molecular sciences}, volume = {23}, number = {19}, pages = {}, pmid = {36232864}, issn = {1422-0067}, support = {SUBZ.D230.22.026//Wrocław Medical University/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Ciprofloxacin ; Gentamicins ; Humans ; Levofloxacin/pharmacology/therapeutic use ; Microbial Sensitivity Tests ; *Osteomyelitis/drug therapy ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; Vancomycin/pharmacology/therapeutic use ; }, abstract = {The biofilm-associated infections of bones are life-threatening diseases, requiring application of dedicated antibiotics in order to counteract the tissue damage and spread of microorganisms. The in vitro analyses on biofilm formation and susceptibility to antibiotics are frequently carried out using methods that do not reflect conditions at the site of infection. To evaluate the influence of nutrient accessibility on Staphylococcus aureus biofilm development in vitro, a cohesive set of analyses in three different compositional media was performed. Next, the efficacy of four antibiotics used in bone infection treatment, including gentamycin, ciprofloxacin, levofloxacin, and vancomycin, against staphylococcal biofilm, was also assessed. The results show a significant reduction in the ability of biofilm to grow in a medium containing elements occurring in the serum, which also translated into the diversified changes in the efficacy of used antibiotics, compared to the setting in which conventional media were applied. The differences indicate the need for implementation of adequate in vitro models that closely mimic the infection site. The results of the present research may be considered an essential step toward the development of in vitro analyses aiming to accurately indicate the most suitable antibiotic to be applied against biofilm-related infections of bones.}, } @article {pmid36230171, year = {2022}, author = {Ciolacu, L and Zand, E and Negrau, C and Jaeger, H}, title = {Bacterial Attachment and Biofilm Formation on Antimicrobial Sealants and Stainless Steel Surfaces.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {19}, pages = {}, pmid = {36230171}, issn = {2304-8158}, support = {866346//Austrian Research Promotion Agency/ ; FO999888198//Austrian Research Promotion Agency/ ; //BOKU Core Facility and Bio Processing/ ; }, abstract = {Biofilms are highly resistant to external forces, especially chemicals. Hence, alternative control strategies, like antimicrobial substances, are forced. Antimicrobial surfaces can inhibit and reduce microbial adhesion to surfaces, preventing biofilm formation. Thus, this research aimed to investigate the bacterial attachment and biofilm formation on different sealants and stainless steel (SS) surfaces with or without antimicrobials on two Gram-positive biofilm forming bacterial strains. Antimicrobial surfaces were either incorporated or coated with anti-microbial, -fungal or/and bactericidal agents. Attachment (after 3 h) and early-stage biofilm formation (after 48 h) of Staphylococcus capitis (S. capitis) and Microbacterium lacticum (M. lacticum) onto different surfaces were assessed using the plate count method. In general, bacterial adhesion on sealants was lower compared to adhesion on SS, for surfaces with and without antimicrobials. Antimicrobial coatings on SS surfaces played a role in reducing early-stage biofilm formation for S. capitis, however, no effects were observed for M. lacticum. S. capitis adhesion and biofilm formation were reduced by 8% and 25%, respectively, on SS coated with an antimicrobial substance (SS_4_M), compared to the same surface without the antimicrobial coating (SS_4_control). Incorporation of both antifungicidal and bactericidal agents (S_5_FB) significantly reduced (p ≤ 0.05) early-stage biofilm formation of M. lacticum, compared to the other sealants incoportating either solely antifungal agents (S_2_F) or no active compound (S_control). Furthermore, the thickness of the coating layer correlated weakly with the antimicrobial effect. Hence, equipment manufacturers and food producers should carefully select antimicrobial surfaces as their effects on bacterial adhesion and early-stage biofilm formation depend on the active agent and bacterial species.}, } @article {pmid36229918, year = {2022}, author = {Ordek, A and Gordesli-Duatepe, FP}, title = {Impact of sodium nitroprusside concentration added to batch cultures of Escherichia coli biofilms on the c-di-GMP levels, morphologies and adhesion of biofilm-dispersed cells.}, journal = {Biofouling}, volume = {38}, number = {8}, pages = {796-813}, doi = {10.1080/08927014.2022.2131399}, pmid = {36229918}, issn = {1029-2454}, mesh = {Bacterial Proteins/genetics ; Batch Cell Culture Techniques ; *Biofilms ; Cyclic GMP ; *Escherichia coli/metabolism ; Gene Expression Regulation, Bacterial ; Nitroprusside/pharmacology ; Plankton/metabolism ; }, abstract = {Biofilm dispersion can be triggered by the application of dispersing agents such as nitric oxide (NO)-donors, resulting in the release of biofilm-dispersed cells into the environment. In this work, biofilm-dispersed cells were obtained by adding different concentrations of NO-donor sodium nitroprusside (0.5, 5, 50 µM, and 2.5 mM of SNP) to batch cultures of pre-formed Escherichia coli biofilms. Except for those dispersed by 5 µM of SNP, biofilm-dispersed cells were found to be wider and longer than the planktonic cells and to have higher c-di-GMP levels and greater adhesion forces to silicon nitride surfaces in water as measured by atomic force microscope. Consequently, the optimum concentration of SNP to disperse E. coli biofilms was found to be 5 µM of SNP, whose addition to batch cultures resulted in a significant biofilm dispersion and the dispersed cells having c-di-GMP levels, morphologies and adhesion strengths similar to their planktonic counterparts.}, } @article {pmid36229871, year = {2022}, author = {Mazurek-Popczyk, J and Nowicki, A and Arkusz, K and Pałka, Ł and Zimoch-Korzycka, A and Baldy-Chudzik, K}, title = {Evaluation of biofilm formation on acrylic resins used to fabricate dental temporary restorations with the use of 3D printing technology.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {442}, pmid = {36229871}, issn = {1472-6831}, mesh = {Acrylamides ; Acrylates ; *Acrylic Resins/chemistry ; Biofilms ; Composite Resins ; *Gentian Violet ; Humans ; Materials Testing ; Methacrylates ; Printing, Three-Dimensional ; Surface Properties ; }, abstract = {BACKGROUND: Temporary implant-retained restorations are required to support function and esthetics of the masticatory system until the final restoration is completed and delivered. Acrylic resins are commonly used in prosthetic dentistry and lately they have been used in three-dimensional (3D) printing technology. Since this technology it is fairly new, the number of studies on their susceptibility to microbial adhesion is low. Restorations placed even for a short period of time may become the reservoir for microorganisms that may affect the peri-implant tissues and trigger inflammation endangering further procedures. The aim of the study was to test the biofilm formation on acrylamide resins used to fabricate temporary restorations in 3D printing technology and to assess if the post-processing impacts microbial adhesion.

METHODS: Disk-shaped samples were manufactured using the 3D printing technique from three commercially available UV-curable resins consisting of acrylate and methacrylate oligomers with various time and inhibitors of polymerization (NextDent MFH bleach, NextDent 3D Plus, MazicD Temp). The tested samples were raw, polished and glazed. The ability to create biofilm by oral streptococci (S. mutans, S. sanguinis, S. oralis, S. mitis) was tested, as well as species with higher pathogenic potential: Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. The roughness of the materials was measured by an atomic force microscope. Biofilm formation was assessed after 72 h of incubation by crystal violet staining with absorbance measurement, quantification of viable microorganisms, and imaging with a scanning electron microscope (SEM).

RESULTS: Each tested species formed the biofilm on the samples of all three resins. Post-production processing resulted in reduced roughness parameters and biofilm abundance. Polishing and glazing reduced roughness parameters significantly in the NextDent resin group, while glazing alone caused significant surface smoothing in Mazic Temp. A thin layer of microbial biofilm covered glazed resin surfaces with a small number of microorganisms for all tested strains except S. oralis and S. epidermidis, while raw and polished surfaces were covered with a dense biofilm, rich in microorganisms.

CONCLUSIONS: UV-curing acrylic resins used for fabricating temporary restorations in the 3D technology are the interim solution, but are susceptible to adhesion and biofilm formation by oral streptococci, staphylococci and Candida. Post-processing and particularly glazing process significantly reduce bacterial biofilm formation and the risk of failure of final restoration.}, } @article {pmid36228305, year = {2022}, author = {Jarros, IC and Veiga, FF and Corrêa, JL and Barros, ILE and Pedroso, RB and Negri, M and Svidzinski, TIE}, title = {Farnesol modulation of Rhodotorula mucilaginosa in biofilm and planktonic forms.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {94}, number = {3}, pages = {e20211127}, doi = {10.1590/0001-3765202220211127}, pmid = {36228305}, issn = {1678-2690}, mesh = {Biofilms ; *Farnesol/pharmacology ; Humans ; Plankton/physiology ; *Rhodotorula ; }, abstract = {Biofilms are important to the virulence of human pathogenic fungi, and some molecules have been found to play key roles in the growth and regulation of fungal biofilms. Farnesol, one of these molecules, is well-described for some microorganisms but is still scarcely known for Rhodotorula spp. This study aimed to evaluate the influence of farnesol on the biofilm of R. mucilaginosa. Initially, screening with 0.2 mM to 2.1 mM of farnesol was evaluated against planktonic forms. A concentration of this compound was then chosen and evaluated for its effect on biofilm in formation and on preformed biofilm after 24, 48 and 72 hours. The impact of farnesol was evaluated by colony-forming units (CFU) counts, determination of metabolic activity and quantification of total biomass. In the presence of 0.9 mM, farnesol was able to decrease the CFU number, at 48 hours, when the biofilm was in formation, although it did not affect the preformed biofilms. Thus, our results show that farnesol exerts a modulating activity during biofilm formation for R. mucilaginosa, with this compound reducing the metabolic activity and total biomass of the biofilms.}, } @article {pmid36224607, year = {2022}, author = {Wang, J and Li, S and Meng, J and Zhu, J and Qiu, T and Wang, W and Ding, J and Liu, Z and Li, K and Lqbal, M and Wang, D and Wu, Y and Liu, J}, title = {Baicalin acts as an adjuvant to potentiate the activity of azithromycin against Staphylococcus saprophyticus biofilm: an in vitro, in vivo, and molecular study.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {83}, pmid = {36224607}, issn = {1297-9716}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Azithromycin/pharmacology ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; Microbial Sensitivity Tests/veterinary ; Staphylococcus saprophyticus ; }, abstract = {Staphylococcus saprophyticus is frequently involved in various difficult-to-treat infections due to the formation of biofilms. To identify useful antibiofilm strategies, this study explored the efficacy and mechanism of baicalin in enhancing the ability of azithromycin against multidrug-resistant Staphylococcus saprophyticus-Liu-2016-Liyang, China-francolin (MDRSS) biofilms in vitro and in vivo. When azithromycin was used in combination with baicalin, the minimum inhibitory concentration in biofilm (MICB) for azithromycin decreased 4- to 512-fold. Compared with the azithromycin and baicalin groups, the combination of azithromycin and baicalin could not reduce the biofilm biomass, but the dispersion rates of biofilm were decreased and the bactericidal ability was increased. Furthermore, the relative transcript levels of WalK/R system-related genes were upregulated by the addition of baicalin or azithromycin plus baicalin compared with that of the azithromycin and blank control groups. The strong correlation relationship between the WalK/R system and the bactericidal index demonstrated that baicalin enhanced the bactericidal effect of azithromycin on MDRSS biofilms by modulating the WalK/R system. In the mouse cutaneous infection model, the combination of azithromycin and baicalin succeeded in eradicating MDRSS and decreasing pathological injuries. This study indicated that baicalin has the potential to be an adjuvant to enhance the antimicrobial activity of azithromycin against MDRSS in the biofilm form by modulating the WalK/R system.}, } @article {pmid36224461, year = {2022}, author = {Costa, EMMB and Maia, CMA and Vasconcelos, PGS and Portela, MB and Barboza, CM and Cardoso, AS and de Araújo Soares, RM and Dos Santos, ALS}, title = {Influence of oral biofilm index, caries experience, and laboratory markers of disease progression on the oral carriage of Candida in HIV-infected and non-infected children: a cross-sectional study.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {4}, pages = {1969-1977}, pmid = {36224461}, issn = {1678-4405}, mesh = {Child ; Humans ; *HIV Infections/complications ; Candida ; Cross-Sectional Studies ; *Acquired Immunodeficiency Syndrome/complications ; Dental Caries Susceptibility ; Biofilms ; Biomarkers ; Disease Progression ; *Dental Caries/complications ; }, abstract = {The present study aimed to compare the oral Candida rate between infected and uninfected children with the human immunodeficiency virus (HIV), as well as analyze the association between Candida spp. and predisposing factors of colonization, like oral biofilm index, caries experience, and laboratory markers of AIDS progression. A cross-sectional study was employed. Candida species were identified and quantified from saliva samples of 50 HIV-infected and 50 uninfected children. Biofilm index and decayed, missing, and filled teeth (dmft/DMFT) indices were assessed by oral clinical examinations. Additionally, CD4[+] T lymphocyte count and viral load were obtained from medical records of the HIV-infected children. Candida species were cultured from 74% of the HIV-infected children and 46% of uninfected ones (p = 0.0076). Candida albicans and Candida parapsilosis were the most frequently isolated species in both studied groups. The isolation of Candida species was significantly higher in HIV-infected children with CD4 ≤ 15% (p = 0.0146); it had influence of mature oral biofilm and the caries index (dmft + DMFT ≥ 8) (p < 0.05) and was associated with the plasma viral load. The present data show that the HIV infection, oral biofilm index, caries experience, and laboratory markers of AIDS progression exert an influence on the prevalence of oral Candida in children.}, } @article {pmid36221149, year = {2022}, author = {Hasson, SO and Judi, HK and Salih, HH and Al-Khaykan, A and Akrami, S and Sabahi, S and Saki, M and Al-Rubaie, ZA}, title = {Intimin (eae) and virulence membrane protein pagC genes are associated with biofilm formation and multidrug resistance in Escherichia coli and Salmonella enterica isolates from calves with diarrhea.}, journal = {BMC research notes}, volume = {15}, number = {1}, pages = {321}, pmid = {36221149}, issn = {1756-0500}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cattle ; Diarrhea/microbiology/veterinary ; Drug Resistance, Multiple/genetics ; Escherichia coli ; *Escherichia coli Infections/microbiology/veterinary ; Membrane Proteins ; *Salmonella enterica ; Virulence ; }, abstract = {OBJECTIVES: This study aimed to evaluate the association of the intimin (eae) and pagC genes with biofilm formation and multidrug resistance (MDR) phenotype in Escherichia coli and Salmonella enterica collected from calves with diarrhea.

RESULTS: Fecal samples (n: 150) were collected from calves with diarrhea. Of 150 fecal samples, 122 (81.3%) were culture positive and 115/122 (94.2%) were Gram-negative bacteria. Among them, E. coli (n = 64/115, 55.6%) was the most common isolate followed by S. enterica (n = 41/115, 35.6%). Also, 10 (8.6%) isolates were other Enterobacteriaceae bacteria including Klebsiella and Proteus species. Eighty-nine isolates (77.4%) from calf diarrhea, including 52 (81.3%) E. coli and 37 (90.2%) S. enterica were MDR. The eae and pagC genes were detected in 33 (51.5%) E. coli and 28 (68.3%) S. enterica isolates, respectively. There was a strong association between these genes and biofilm formation and MDR phenotype (P-value = 0.000). All E. coli isolates carrying the eae gene were biofilm producers and MDR. Also, all pagC-positive S. enterica isolates were MDR and 25 (89.3%) isolates of them produced biofilm.}, } @article {pmid36221053, year = {2022}, author = {Abdelghafar, A and Yousef, N and Askoura, M}, title = {Zinc oxide nanoparticles reduce biofilm formation, synergize antibiotics action and attenuate Staphylococcus aureus virulence in host; an important message to clinicians.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {244}, pmid = {36221053}, issn = {1471-2180}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria/metabolism ; Biofilms ; Gentian Violet/pharmacology ; Hemolysis ; Iron-Dextran Complex/pharmacology ; *Metal Nanoparticles/chemistry ; Mice ; Microbial Sensitivity Tests ; *Nanoparticles/chemistry ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; Virulence ; *Zinc Oxide/chemistry/pharmacology ; }, abstract = {BACKGROUND: Biofilm-related infections are difficult to be treated because of higher resistance to antimicrobial agents. Current study aims to characterize the influence of zinc oxide nanoparticles (ZnO-NPs) on both S. aureus susceptibility to antibiotics and pathogenesis.

METHODS: The influence of ZnO-NPs on biofilm formation by S. aureus was characterized by the crystal violet and tube assay. The synergistic effect of ZnO-NPs in combination with antibiotics on S. aureus was characterized using the checkerboard method. The effect of ZnO-NPs on S. aureus cell surface hydrophobicity and blood hemolysis was investigated. RT-qPCR was used to investigate the effect of ZnO-NPs on the expression of biofilm related genes (icaA, icaR and sarA), katA and sigB. The impact of ZnO-NPs on S. aureus pathogenesis was evaluated using mice infection model.

RESULTS: ZnO-NPs exhibited a good antibiofilm activity against S. aureus. The findings indicate a synergistic antibiofilm effect of combination between ZnO-NPs and tested antibiotics. ZnO-NPs were capable of decreasing S. aureus cell surface hydrophobicity which could account for observed decrease in bacterial biofilm forming capacity. Moreover, ZnO-NPs-treated bacteria exhibited a significant decrease in blood hemolysis relative to control untreated S. aureus. The expression of biofilm related genes was significantly repressed in ZnO-NPs treated bacteria as compared to untreated cells. Finally, the effect of ZnO-NPs on S. aureus pathogenesis was investigated using mice infection model where ZnO-NPs accelerated healing of wounds in mice as compared to control untreated mice.

CONCLUSIONS: Present data support the efficiency of ZnO-NPs as antibiofilm agent in treatment of S. aureus infections. This study recommends the incorporation of ZnO-NPs as adjuvant with other antibiotics targeting S. aureus based on the promising findings obtained herein in order to control infection with this pathogen.}, } @article {pmid36219300, year = {2023}, author = {Tang, P and Chen, L and Zhang, W and Zhou, Y}, title = {Bioclogging alleviation for constructed wetland based on the interaction among biofilm growth and hydrodynamics.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {7}, pages = {18755-18763}, pmid = {36219300}, issn = {1614-7499}, support = {51878597//National Natural Science Foundation of China/ ; }, mesh = {*Wetlands ; *Hydrodynamics ; Models, Theoretical ; Biofilms ; Porosity ; Waste Disposal, Fluid/methods ; }, abstract = {Bioclogging is the most crucial operation problem of the constructed wetlands, which reduce its removal efficiency and life span. A strategy through properly increasing hydraulic loading is proposed in this study to alleviate the bioclogging for CWs. The two-dimensional porous media flow cell (2D PMFC) test indicated that a quadratic correlation was found between local biofilms growth rate and the near-wall Reynolds number (r > 0.765, p < 0.05). The biofilm growth rate declined with the flowrate when Re exceeded about 6.0. It was also found that the higher flowrate (6 mL/min) lead to the homogeneous biofilm and velocity distribution in the PMFC. The column test indicated that the highest hydraulic loading (9.2 cm/h) produced the smallest decrease in hydraulic conductivity, which was 80 times more than that of low hydraulic load (3.0 cm/h) at the end (40 days) of experiment. Moreover, the relatively homogenized distribution of biofilm was found along the column with the highest hydraulic loading, which confirmed that the proper increase in hydraulic loading can alleviate bioclogging.}, } @article {pmid36218343, year = {2022}, author = {Thomas, LS and Cook, LC}, title = {A Novel Conserved Protein in Streptococcus agalactiae, BvaP, Is Important for Vaginal Colonization and Biofilm Formation.}, journal = {mSphere}, volume = {7}, number = {6}, pages = {e0042122}, pmid = {36218343}, issn = {2379-5042}, support = {F31AI154817//HHS | National Institutes of Health (NIH)/ ; }, mesh = {Female ; Infant, Newborn ; Animals ; Mice ; Humans ; *Streptococcus agalactiae ; *Streptococcal Infections ; Vagina ; Biofilms ; }, abstract = {Streptococcus agalactiae (group B streptococcus [GBS]) infections in neonates are often fatal and strongly associated with maternal GBS vaginal colonization. Here, we investigated the role of an uncharacterized protein, BvaP, in GBS vaginal colonization. bvaP was previously identified as the most highly upregulated gene in the GBS A909 transcriptome when comparing vaginal colonization to growth in liquid culture. We found that the absence of BvaP affects the ability of GBS to adhere to extracellular matrix components and human vaginal epithelial cells, and the ability of a ΔbvaP mutant to colonize the murine vaginal tract was significantly decreased. Cellular morphological alterations such as changes in cell shape, chain length, and clumping were also observed in a knockout mutant strain. Given its high expression level in vivo, high degree of conservation among GBS strains, and role in vaginal colonization, BvaP may be an eligible target for GBS vaccination and/or drug therapy. IMPORTANCE Neonatal GBS disease is a major cause of morbidity and mortality, and maternal vaginal colonization is the leading risk factor for the disease. Colonization prevention would greatly impact the rates of disease transmission, but vaccine development has stalled as capsular polysaccharide vaccines have low immunogenicity in vivo. While these vaccines are still in development, the addition of a protein conjugate may prove fruitful in increasing immunogenicity and strain coverage across GBS serotypes. Previous research identified sak_1753 as a highly upregulated gene during murine vaginal colonization. This study reveals that Sak_1753 is required to maintain proper GBS cellular morphology and colonization phenotypes and is required for full in vivo vaginal colonization in a murine model. We have renamed Sak_1753 group B streptococcus vaginal adherence protein (BvaP). The findings of this study indicate that BvaP is important for GBS colonization of the vaginal tract and, given its high expression level in vivo and strain conservation, may be a candidate for vaccine development.}, } @article {pmid36217393, year = {2022}, author = {Patel, RD and Gross, MS}, title = {Biofilm review highlights need for new research.}, journal = {Translational andrology and urology}, volume = {11}, number = {9}, pages = {1224-1225}, pmid = {36217393}, issn = {2223-4691}, } @article {pmid36216771, year = {2022}, author = {Dai, Y and Mei, J and Li, Z and Kong, L and Zhu, W and Li, Q and Wu, K and Huang, Y and Shang, X and Zhu, C}, title = {Acidity-Activatable Nanoparticles with Glucose Oxidase-Enhanced Photoacoustic Imaging and Photothermal Effect, and Macrophage-Related Immunomodulation for Synergistic Treatment of Biofilm Infection.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {18}, number = {46}, pages = {e2204377}, doi = {10.1002/smll.202204377}, pmid = {36216771}, issn = {1613-6829}, mesh = {Glucose Oxidase ; *Photoacoustic Techniques ; *Hyperthermia, Induced/methods ; *Nanoparticles ; Biofilms ; Macrophages ; Immunomodulation ; }, abstract = {The pH-responsive theragnostics exhibit great potential for precision diagnosis and treatment of diseases. Herein, acidity-activatable nanoparticles of GB@P based on glucose oxidase (GO) and polyaniline are developed for treatment of biofilm infection. Catalyzed by GO, GB@P triggers the conversion of glucose into gluconic acid and hydrogen peroxide (H2 O2), enabling an acidic microenvironment-activated simultaneously enhanced photothermal (PT) effect/amplified photoacoustic imaging (PAI). The synergistic effects of the enhanced PT efficacy of GB@P and H2 O2 accelerate biofilm eradication because the penetration of H2 O2 into biofilm improves the bacterial sensitivity to heat, and the enhanced PT effect destroys the expressions of extracellular DNA and genomic DNA, resulting in biofilm destruction and bacterial death. Importantly, GB@P facilitates the polarization of proinflammatory M1 macrophages that initiates macrophage-related immunity, which enhances the phagocytosis of macrophages and secretion of proinflammatory cytokines, leading to a sustained bactericidal effect and biofilm eradication by the innate immunomodulatory effect. Accordingly, the nanoplatform of GB@P exhibits the synergistic effects on the biofilm eradication and bacterial residuals clearance through a combination of the enhanced PT effect with immunomodulation. This study provides a promising nanoplatform with enhanced PT efficacy and amplified PAI for diagnosis and treatment of biofilm infection.}, } @article {pmid36215099, year = {2022}, author = {Balmaceda, RS and Ramos Ricciuti, FE and Redersdorff, IE and Veinticcinque, LM and Studdert, CA and Herrera Seitz, MK}, title = {Chemosensory pathways of Halomonas titanicae KHS3 control chemotaxis behaviour and biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {168}, number = {10}, pages = {}, doi = {10.1099/mic.0.001251}, pmid = {36215099}, issn = {1465-2080}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Chemotaxis/genetics ; Escherichia coli/metabolism ; *Halomonas/genetics ; }, abstract = {Halomonas titanicae KHS3 is a marine bacterium whose genome codes for two different chemosensory pathways. Chemosensory gene cluster 1 is very similar to the canonical Che cluster from Escherichia coli. Chemosensory cluster 2 includes a gene coding for a diguanylate cyclase with receiver domains, suggesting that it belongs to the functional group that regulates alternative cellular functions other than chemotaxis. In this work we assess the functional roles of both chemosensory pathways through approaches that include the heterologous expression of Halomonas proteins in E. coli strains and phenotypic analyses of Halomonas mutants. Our results confirm that chemosensory cluster 1 is indeed involved in chemotaxis behaviour, and only proteins from this cluster complement E. coli defects. We present evidence suggesting that chemosensory cluster 2 resembles the Wsp pathway from Pseudomonas, since the corresponding methylesterase mutant shows an increased methylation level of the cognate receptor and develops a wrinkly colony morphology correlated with an increased ability to form biofilm. Consistently, mutational interruption of this gene cluster correlates with low levels of biofilm. Our results suggest that the proteins from each pathway assemble and function independently. However, the phenotypic characteristics of the mutants show functional connections between the pathways controlled by each chemosensory system.}, } @article {pmid36214729, year = {2023}, author = {Hoffstedt, T and Skov Hansen, LB and Twetman, S and Sonesson, M}, title = {Effect of an enzyme-containing mouthwash on the dental biofilm and salivary microbiome in patients with fixed orthodontic appliances: a randomized placebo-controlled pilot trial.}, journal = {European journal of orthodontics}, volume = {45}, number = {1}, pages = {96-102}, pmid = {36214729}, issn = {1460-2210}, mesh = {Male ; Adolescent ; Female ; Humans ; Mouthwashes/therapeutic use ; Pilot Projects ; Orthodontic Appliances, Fixed/adverse effects ; *Dental Plaque/etiology ; Biofilms ; *Microbiota ; Orthodontic Appliances/adverse effects ; }, abstract = {BACKGROUND: Mouthwashes containing oral antiseptics or enzymes are suggested suitable for controlling biofilm accumulation in patients with fixed appliances and thereby limiting unwanted side effects during the orthodontic treatment.

OBJECTIVES: To evaluate the effect of an enzyme-based mouthwash on the amount of dental biofilm and the composition of the salivary microbiome in patients undergoing treatment with fixed orthodontic appliances.

TRIAL DESIGN: Randomized double-blind placebo-controlled trial.

MATERIAL AND METHODS: In total, 35 young adolescents (14-18 years) under treatment with fixed appliances were consecutively enrolled and randomly allocated to an experimental or a placebo group by opening a computer-generated numbered envelope. The subjects were instructed to rinse twice daily during an intervention period of 8 days with experimental mouthwash or placebo without active enzymes. Unstimulated whole saliva samples were collected at baseline and after 8 days. The participants and examiner were blinded for the allocation. The primary outcome was the Orthodontic Plaque Index (OPI) and the secondary was the composition of the salivary microbiome.

RESULTS: In total, 28 adolescents (21 females and 7 males) completed the trial and there were no differences in age, clinical, or microbial findings between the test (n = 14) and the placebo group (n = 14) at baseline. We found a decreased OPI in the test group after 8 days and the difference was statistically significant compared with the placebo group (P < 0.05). There were no significant treatment effects on the richness and global composition of the salivary microbiome.

HARMS: In total, one participant in the test group claimed nausea and abandoned the project. In total, two participants did not like the taste of the mouthwash but used it as instructed. No other adverse events or side effects were reported.

LIMITATIONS: Short-term pilot trials may by nature be sensitive for selection and performance biases and are not designed to unveil persisting effects.

CONCLUSION: Daily use of enzyme-containing mouthwash reduced the amount of dental biofilm in adolescents under treatment with the fixed orthodontic appliances, without affecting the composition of the salivary microbiota.

ETHICAL APPROVAL: Approved by the Regional Ethical Board, Lund, Sweden (Dnr 2020-05221).

CLINICAL TRIAL REGISTRATION: NCT05033015.}, } @article {pmid36214177, year = {2022}, author = {Li, J and Cheung, WH and Chow, SK and Ip, M and Leung, SYS and Wong, RMY}, title = {Current therapeutic interventions combating biofilm-related infections in orthopaedics : a systematic review of in vivo animal studies.}, journal = {Bone & joint research}, volume = {11}, number = {10}, pages = {700-714}, pmid = {36214177}, issn = {2046-3758}, abstract = {AIMS: Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models.

METHODS: Literature research was performed on PubMed and Embase databases. Keywords used for search criteria were "bone AND biofilm". Information on the species of the animal model, bacterial strain, evaluation of biofilm and bone infection, complications, key findings on observations, prevention, and treatment of biofilm were extracted.

RESULTS: A total of 43 studies were included. Animal models used included fracture-related infections (ten studies), periprosthetic joint infections (five studies), spinal infections (three studies), other implant-associated infections, and osteomyelitis. The most common bacteria were Staphylococcus species. Biofilm was most often observed with scanning electron microscopy. The natural history of biofilm revealed that the process of bacteria attachment, proliferation, maturation, and dispersal would take 14 days. For systemic mono-antibiotic therapy, only two of six studies using vancomycin reported significant biofilm reduction, and none reported eradication. Ten studies showed that combined systemic and topical antibiotics are needed to achieve higher biofilm reduction or eradication, and the effect is decreased with delayed treatment. Overall, 13 studies showed promising therapeutic potential with surface coating and antibiotic loading techniques.

CONCLUSION: Combined topical and systemic application of antimicrobial agents effectively reduces biofilm at early stages. Future studies with sustained release of antimicrobial and biofilm-dispersing agents tailored to specific pathogens are warranted to achieve biofilm eradication.Cite this article: Bone Joint Res 2022;11(10):670-684.}, } @article {pmid36212949, year = {2022}, author = {Adeyemo, RO and Famuyide, IM and Dzoyem, JP and Lyndy Joy, M}, title = {Anti-Biofilm, Antibacterial, and Anti-Quorum Sensing Activities of Selected South African Plants Traditionally Used to Treat Diarrhoea.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2022}, number = {}, pages = {1307801}, pmid = {36212949}, issn = {1741-427X}, abstract = {The development of resistance of microorganisms to conventional antibiotics is a major global health concern; hence, there is an increasing interest in medicinal plants as a therapeutic option. This study aimed to evaluate the antibacterial, anti-biofilm, and anti-quorum activities of crude extracts prepared using various solvents of nine indigenous South African plants used locally for the treatment of diarrhoea. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method and the crystal violet assay was used to test the anti-biofilm activity of the extracts against a panel of bacteria. Anti-quorum sensing activity of the extracts was assessed via inhibition of violacein production in Chromobacterium violaceum ATCC 12472. Preliminary screening of extracts against E. coli ATCC 25922 revealed that the acetone extracts had significant activity, with MIC values ranging from 0.04 to 0.63 mg/mL. Further screening against a panel of bacterial pathogens showed that the acetone extract of Bauhinia bowkeri was the most active with MIC of 0.01 mg/mL against Salmonella enteritidis, followed by Searsia lancea with MIC of 0.03 mg/mL against Bacillus cereus. All the plant extracts prevented the attachment of biofilms by more than 50% against at least one of the tested bacteria. However, only the mature biofilm of B. cereus was susceptible to the extracts, with 98.22% eradication by Searsia pendulina extract. The minimum quorum sensing inhibitory concentration of the extracts ranged from 0.08 to 0.32 mg/mL with S. lancea having the most significant activity. The extract of S. lancea had the best violacein production inhibitory activity with IC50 value of 0.17 mg/mL. Overall, the results obtained indicate that acetone extracts of S. leptodictya, S. lancea, S. batophylla, S. pendulina, B. galpinii, and B. bowkeri possess antibacterial and anti-biofilm activities and can modulate quorum sensing through the inhibition of violacein production. Therefore, these results signify the potential of the selected plant extracts in treating diarrhoea through inhibition of bacterial growth, biofilm formation inhibition, and quorum sensing antagonism, supporting their medicinal use.}, } @article {pmid36212837, year = {2022}, author = {Shakya, S and Danshiitsoodol, N and Noda, M and Inoue, Y and Sugiyama, M}, title = {3-Phenyllactic acid generated in medicinal plant extracts fermented with plant-derived lactic acid bacteria inhibits the biofilm synthesis of Aggregatibacter actinomycetemcomitans.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {991144}, pmid = {36212837}, issn = {1664-302X}, abstract = {In the present study, the effect of PLA on a periodontic pathogen, Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), the biofilm, and virulence-related genes was investigated. We confirmed that two lactic acid bacteria (LAB) strains isolated from plant sources, Lactiplantibacillus plantarum MSC-C2 and Pediococcus pentosaceus K40, secrete PLA into the de Man, Rogosa & Sharpe (MRS) broth when supplemented with phenyl pyruvic acid (PPA) as a precursor to PLA. Moreover, PLA was generated in the fermentation broths of two medicinal plant extracts, Paeonia lactiflora Pall (PR) and Carthamus tinctorius (CT), when used by each LAB strain and each extract supplemented with PPA. We determined that the minimum inhibitory concentration (MIC) of PLA against A. actinomycetemcomitans was 20 mM. PLA significantly decreased biofilm formation and suppressed the transcription of pgA, ltxA, and cdtB genes, which encode the poly-N-acetylglucosamine (PGA) polysaccharide of biofilm matrix and exotoxins leukotoxin and cytolethal distending toxin (CDT), respectively. The PLA produced by the MSC-C2 and K40 strains was increased several times by the addition of PPA to the MRS broth. The anti-biofilm effect of the extracts from the fermentation broth was proportional to the increasing PLA concentration, while a cumulatively higher effect than that of PLA alone suggested a combinational effect of PLA and the other metabolites, such as lactic acid (LA). Among the two medicinal plants, PLA, produced after the addition of PPA, was higher in PR extract in case of both the LAB strains. PLA production by the MSC-C2 strain in the PR extract reached 4.8 ± 0.23 mM, which was obviously higher than that in the MRS broth (3.88 ± 0.12 mM) supplemented with 1 mg/ml PPA. The activity to inhibit biofilm formation in the fermented PR extract was clearly high. PLA formed in the fermented PR extract downregulated the dispersin B encoding the dspB gene together with pgA, ltxA, and cdtB. In conclusion, this study shows a promising activity of PLA against the A. actinomycetemcomitans biofilm and virulence genes. In addition, the combinational effect of PLA and the medicinal plant extract can be achieved by fermentation with a specific plant-derived LAB strain.}, } @article {pmid36212831, year = {2022}, author = {Cortesão, M and Holland, G and Schütze, T and Laue, M and Moeller, R and Meyer, V}, title = {Colony growth and biofilm formation of Aspergillus niger under simulated microgravity.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {975763}, pmid = {36212831}, issn = {1664-302X}, abstract = {The biotechnology- and medicine-relevant fungus Aspergillus niger is a common colonizer of indoor habitats such as the International Space Station (ISS). Being able to colonize and biodegrade a wide range of surfaces, A. niger can ultimately impact human health and habitat safety. Surface contamination relies on two key-features of the fungal colony: the fungal spores, and the vegetative mycelium, also known as biofilm. Aboard the ISS, microorganisms and astronauts are shielded from extreme temperatures and radiation, but are inevitably affected by spaceflight microgravity. Knowing how microgravity affects A. niger colony growth, in particular regarding the vegetative mycelium (biofilm) and spore production, will help prevent and control fungal contaminations in indoor habitats on Earth and in space. Because fungal colonies grown on agar can be considered analogs for surface contamination, we investigated A. niger colony growth on agar in normal gravity (Ground) and simulated microgravity (SMG) conditions by fast-clinorotation. Three strains were included: a wild-type strain, a pigmentation mutant (ΔfwnA), and a hyperbranching mutant (ΔracA). Our study presents never before seen scanning electron microscopy (SEM) images of A. niger colonies that reveal a complex ultrastructure and biofilm architecture, and provide insights into fungal colony development, both on ground and in simulated microgravity. Results show that simulated microgravity affects colony growth in a strain-dependent manner, leading to thicker biofilms (vegetative mycelium) and increased spore production. We suggest that the Rho GTPase RacA might play a role in A. niger's adaptation to simulated microgravity, as deletion of ΔracA leads to changes in biofilm thickness, spore production and total biomass. We also propose that FwnA-mediated melanin production plays a role in A. niger's microgravity response, as ΔfwnA mutant colonies grown under SMG conditions showed increased colony area and spore production. Taken together, our study shows that simulated microgravity does not inhibit A. niger growth, but rather indicates a potential increase in surface-colonization. Further studies addressing fungal growth and surface contaminations in spaceflight should be conducted, not only to reduce the risk of negatively impacting human health and spacecraft material safety, but also to positively utilize fungal-based biotechnology to acquire needed resources in situ.}, } @article {pmid36212814, year = {2022}, author = {Chen, Y and Hu, H and Huang, F and Ling, Z and Chen, B and Tan, B and Wang, T and Liu, X and Liu, C and Zou, X}, title = {Cocktail of isobavachalcone and curcumin enhance eradication of Staphylococcus aureus biofilm from orthopedic implants by gentamicin and alleviate inflammatory osteolysis.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {958132}, pmid = {36212814}, issn = {1664-302X}, abstract = {Orthopedic device-related infection (ODRI) caused by Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA) biofilm may lead to persist infection and severe inflammatory osteolysis. Previous studies have demonstrated that both isobavachalcone and curcumin possess antimicrobial activity, recent studies also reveal their antiosteoporosis, anti-inflammation, and immunoregulatory effect. Thus, this study aims to investigate whether the combination of isobavachalcone and curcumin can enhance the anti-S. aureus biofilm activity of gentamicin and alleviate inflammatory osteolysis in vivo. EUCAST and a standardized MBEC assay were used to verify the synergy between isobavachalcone and curcumin with gentamicin against planktonic S. aureus and its biofilm in vitro, then the antimicrobial and immunoregulatory effect of cocktail therapy was demonstrated in a femoral ODRI mouse model in vivo by μCT analysis, histopathology, quantification of bacteria in bone and myeloid-derived suppressor cell (MDSC) in bone marrow. We tested on standard MSSA ATCC25923 and MRSA USA300, 5 clinical isolated MSSA, and 2 clinical isolated MRSA strains and found that gentamicin with curcumin (62.5-250 μg/ml) and gentamicin with isobavachalcone (1.56 μg/ml) are synergistic against planktonic MSSA, while gentamicin (128 μg/ml) with curcumin (31.25-62.5, 250-500 μg/ml) and gentamicin (64-128 μg/ml) with isobavachalcone (1.56-12.5 μg/ml) exhibit synergistic effect against MSSA biofilm. Results of further study revealed that cocktail of 128 μg/ml gentamicin together with 125 μg/ml curcumin +6.25 μg/ml isobavachalcone showed promising biofilm eradication effect with synergy against USA300 biofilm in vitro. Daily intraperitoneal administration of 20 mg/kg/day isobavachalcone, 20 mg/kg/day curcumin, and 20 mg/kg/day gentamicin, can reduce inflammatory osteolysis and maintain microarchitecture of trabecular bone during orthopedic device-related MRSA infection in mice. Cocktail therapy also enhanced reduction of MDSC M1 polarization in peri-implant tissue, suppression of MDSC amplification in bone marrow, and Eradication of USA300 biofilm in vivo. Together, these results suggest that the combination of isobavachalcone and curcumin as adjuvants administrated together with gentamicin significantly enhances its antimicrobial effect against S. aureus biofilm, and can also modify topical inflammation in ODRI and protect bone microstructure in vivo, which may serve as a potential treatment strategy, especially for S. aureus induced ODRI.}, } @article {pmid36211965, year = {2022}, author = {Ma, R and Hu, X and Zhang, X and Wang, W and Sun, J and Su, Z and Zhu, C}, title = {Strategies to prevent, curb and eliminate biofilm formation based on the characteristics of various periods in one biofilm life cycle.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1003033}, pmid = {36211965}, issn = {2235-2988}, mesh = {Animals ; *Anti-Bacterial Agents/metabolism/pharmacology ; Bacteria/metabolism ; *Biofilms ; Deoxyribonuclease I ; Life Cycle Stages ; Peptide Hydrolases ; }, abstract = {Biofilms are colonies of bacteria embedded inside a complicated self-generating intercellular. The formation and scatter of a biofilm is an extremely complex and progressive process in constant cycles. Once formed, it can protect the inside bacteria to exist and reproduce under hostile conditions by establishing tolerance and resistance to antibiotics as well as immunological responses. In this article, we reviewed a series of innovative studies focused on inhibiting the development of biofilm and summarized a range of corresponding therapeutic methods for biological evolving stages of biofilm. Traditionally, there are four stages in the biofilm formation, while we systematize the therapeutic strategies into three main periods precisely:(i) period of preventing biofilm formation: interfering the colony effect, mass transport, chemical bonds and signaling pathway of plankton in the initial adhesion stage; (ii) period of curbing biofilm formation:targeting several pivotal molecules, for instance, polysaccharides, proteins, and extracellular DNA (eDNA) via polysaccharide hydrolases, proteases, and DNases respectively in the second stage before developing into irreversible biofilm; (iii) period of eliminating biofilm formation: applying novel multifunctional composite drugs or nanoparticle materials cooperated with ultrasonic (US), photodynamic, photothermal and even immune therapy, such as adaptive immune activated by stimulated dendritic cells (DCs), neutrophils and even immunological memory aroused by plasmocytes. The multitargeted or combinational therapies aim to prevent it from developing to the stage of maturation and dispersion and eliminate biofilms and planktonic bacteria simultaneously.}, } @article {pmid36211963, year = {2022}, author = {Kašparová, P and Vaňková, E and Paldrychová, M and Svobodová, A and Hadravová, R and Jarošová Kolouchová, I and Masák, J and Scholtz, V}, title = {Non-thermal plasma causes Pseudomonas aeruginosa biofilm release to planktonic form and inhibits production of Las-B elastase, protease and pyocyanin.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {993029}, pmid = {36211963}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Endopeptidases/pharmacology ; Gelatinases/pharmacology ; Hemolysin Proteins/pharmacology ; Humans ; Pancreatic Elastase ; Peptide Hydrolases ; Plankton ; *Plasma Gases/pharmacology ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; Pyocyanine ; Quorum Sensing ; Virulence Factors ; }, abstract = {The increasing risk of antibiotic failure in the treatment of Pseudomonas aeruginosa infections is largely related to the production of a wide range of virulence factors. The use of non-thermal plasma (NTP) is a promising alternative to antimicrobial treatment. Nevertheless, there is still a lack of knowledge about the effects of NTP on the virulence factors production. We evaluated the ability of four NTP-affected P. aeruginosa strains to re-form biofilm and produce Las-B elastase, proteases, lipases, haemolysins, gelatinase or pyocyanin. Highly strains-dependent inhibitory activity of NTP against extracellular virulence factors production was observed. Las-B elastase activity was reduced up to 82% after 15-min NTP treatment, protease activity and pyocyanin production by biofilm cells was completely inhibited after 60 min, in contrast to lipases and gelatinase production, which remained unchanged. However, for all strains tested, a notable reduction in biofilm re-development ability was depicted using spinning disc confocal microscopy. In addition, NTP exposure of mature biofilms caused disruption of biofilm cells and their dispersion into the environment, as shown by transmission electron microscopy. This appears to be a key step that could help overcome the high resistance of P. aeruginosa and its eventual elimination, for example in combination with antibiotics still highly effective against planktonic cells.}, } @article {pmid36210503, year = {2022}, author = {Chalke, S and Vidovic, S and Fletcher, GC and Palmer, J and Flint, S}, title = {Differential effects of magnesium, calcium, and sodium on Listeria monocytogenes biofilm formation.}, journal = {Biofouling}, volume = {38}, number = {8}, pages = {786-795}, doi = {10.1080/08927014.2022.2131398}, pmid = {36210503}, issn = {1029-2454}, mesh = {*Listeria monocytogenes ; Magnesium/pharmacology ; Calcium/pharmacology ; Food Microbiology ; Biofilms ; Bacterial Adhesion ; Sodium/pharmacology ; Cations, Divalent/pharmacology ; Food Contamination/analysis ; }, abstract = {Listeria monocytogenes is a gram-positive foodborne pathogen that causes outbreaks of listeriosis associated with a diverse range of foods. L. monocytogenes forms biofilms as a strategy to enhance its survival in the environment. These biofilms then provide a source of contamination in processing plant environments. Cations like magnesium, calcium, and sodium are commonly found in the environment and are important to bacteria to maintain their homeostasis. It is, therefore, valuable to understand the relationship between these cations and biofilm formation. In this study, four isolates of L. monocytogenes from seafood processing environments were used to investigate the influence of magnesium, calcium, and sodium (1, 10, and 50 mM) on biofilms. The isolates selected were defined as being either a low biofilm former, a high biofilm former, an outbreak isolate, and a persistent isolate from the seafood industry. The study showed that the divalent cations magnesium and calcium increased biofilm formation compared with the monovalent cation, sodium. Fifty mM concentrations of the divalent cations significantly enhanced biofilm formation. The cations did not have a significant effect on the initial stages of biofilm formation but appeared to influence the later stages of biofilm development.}, } @article {pmid36210039, year = {2022}, author = {Shakeel, M and Majeed, MI and Nawaz, H and Rashid, N and Ali, A and Haque, A and Akbar, MU and Tahir, M and Munir, S and Ali, Z and Shahbaz, M and Saleem, M}, title = {Surface-enhanced Raman spectroscopy for the characterization of pellets of biofilm forming bacterial strains of Staphylococcus epidermidis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103145}, doi = {10.1016/j.pdpdt.2022.103145}, pmid = {36210039}, issn = {1873-1597}, mesh = {Spectrum Analysis, Raman/methods ; Staphylococcus epidermidis ; Silver/chemistry ; *Metal Nanoparticles/chemistry ; *Photochemotherapy/methods ; }, abstract = {BACKGROUND: Surface-enhanced Raman spectroscopy (SERS) is an effective tool for identifying biofilm forming bacterial strains. Biofilm forming bacteria are considered a major issue in the health sector because they have strong resistance against antibiotics. Staphylococcus epidermidis is commonly present on intravascular devices and prosthetic joints, catheters and wounds.

OBJECTIVES: To identify and characterize biofilm forming and non-biofilm forming bacterial strains, surface- enhanced Raman spectroscopy with principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) were used.

METHODS: Surface-enhanced Raman spectroscopy (SERS) with silver nanoparticles were employed for the analysis and characterization of biofilm forming bacterial strains. SERS is used to differentiate between non biofilm forming (five samples), medium biofilm forming (five samples) and strong biofilm forming (five samples) bacterial strains by applying silver nanoparticles (AgNPs) as SERS substrate. Principal component analysis (PCA) and Partial least square discriminant analysis (PLS-DA) were used to discriminate between non, medium and strong biofilm ability of bacterial strains.

RESULTS: Principal component analysis (PCA) and Partial least square discriminant analysis (PLS-DA) have been used to identify the biochemical differences in the form of SERS features which can be used to differentiate between biofilm forming and non-biofilm forming bacterial strains. PLS-DA provides successful differentiation and classification of these different strains with 94.5% specificity, 96% sensitivity and 89% area under the curve (AUC).

CONCLUSIONS: Surface-enhanced Raman spectroscopy can be utilized to differentiate between non, medium and strong biofilm forming bacterial strains.}, } @article {pmid36209853, year = {2022}, author = {Cao, L and Ge, R and Xu, W and Zhang, Y and Li, G and Xia, X and Zhang, F}, title = {Simultaneous removal of nitrate, nitrobenzene and aniline from groundwater in a vertical baffled biofilm reactor.}, journal = {Chemosphere}, volume = {309}, number = {Pt 1}, pages = {136746}, doi = {10.1016/j.chemosphere.2022.136746}, pmid = {36209853}, issn = {1879-1298}, mesh = {*Nitrates/metabolism ; Bioreactors/microbiology ; Nitrobenzenes ; Biofilms ; *Groundwater ; Aniline Compounds ; Oxygen ; Denitrification ; Nitrogen ; }, abstract = {The challenge of simultaneous removal of nitrobenzene (NB), aniline (AN) and nitrate from groundwater in a single bioreactor is mainly attributed to the persistence of AN to degradation with anoxic denitrification conditions. In this work, simultaneous removal of NB (100 μM), AN (100 μM) and nitrate (1 mM) was achieved within 8 h with a COD/N ratio of 8 in a vertical baffled biofilm reactor (VBBR). By setting DO concentration at 0.4-0.5 mg L[-1] to create a micro-aerobic condition, NB removal rate was accelerated without accumulation of AN, and AN could serve as electron donors for denitrification after ring cleavage. High-throughput sequencing showed that biofilm was predominated by denitrifiers (Luteimonas, Planctomyces, Thiobacillus, Thauera and so on) and NB-degrading bacteria (Pseudomonas), and biodiversity varied vertically along the height of the reactor. A dominantly anaerobic pathway for reducing NB to AN was identified by PICRUSt analysis, as the predicted genes involved in aerobic transformation of NB were several magnitudes lower than those in the anaerobic pathway. This study provided a new insight to the role of oxygen in robust bioremediation groundwater contaminated with NB, AN and nitrate.}, } @article {pmid36209206, year = {2022}, author = {Zhang, Y and Cheng, P and Wang, S and Li, X and Peng, L and Fang, R and Xiong, J and Li, H and Mei, C and Gao, J and Song, Z and Xu, D and Fu, L and Li, C and Wu, X and He, Y and Chen, H}, title = {Pseudomonas aeruginosa biofilm dispersion by the mouse antimicrobial peptide CRAMP.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {80}, pmid = {36209206}, issn = {1297-9716}, support = {CYS21134//Graduate Research and Innovation Projects of Chongqing/ ; XDJK2019B040//Fundamental Research Funds for the Central Universities/ ; SWU120057//Fundamental Research Funds for the Central Universities/ ; cstc2018jcyjAX0466//Chongqing basic research and frontier exploration project/ ; cstc2019ngzx0014//Chongqing Rongchang Agricultural and Animal Husbandry High-tech Industry Research and Development Project/ ; 32102684//National Outstanding Youth Science Fund Project of National Natural Science Foundation of China/ ; }, mesh = {Alginates/metabolism ; Animals ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides ; *Antimicrobial Peptides ; Bacterial Proteins/genetics ; Biofilms ; Cyclic GMP ; Gene Expression Regulation, Bacterial ; Guanosine Monophosphate/metabolism ; Mice ; Proteomics ; *Pseudomonas aeruginosa/metabolism ; Cathelicidins ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is a known bacterium that produces biofilms and causes severe infection. Furthermore, P. aeruginosa biofilms are extremely difficult to eradicate, leading to the development of chronic and antibiotic-resistant infections. Our previous study showed that a cathelicidin-related antimicrobial peptide (CRAMP) inhibits the formation of P. aeruginosa biofilms and markedly reduces the biomass of preformed biofilms, while the mechanism of eradicating bacterial biofilms remains elusive. Therefore, in this study, the potential mechanism by which CRAMP eradicates P. aeruginosa biofilms was investigated through an integrative analysis of transcriptomic, proteomic, and metabolomic data. The omics data revealed CRAMP functioned against P. aeruginosa biofilms by different pathways, including the Pseudomonas quinolone signal (PQS) system, cyclic dimeric guanosine monophosphate (c-di-GMP) signalling pathway, and synthesis pathways of exopolysaccharides and rhamnolipid. Moreover, a total of 2914 differential transcripts, 785 differential proteins, and 280 differential metabolites were identified. A series of phenotypic validation tests demonstrated that CRAMP reduced the c-di-GMP level with a decrease in exopolysaccharides, especially alginate, in P. aeruginosa PAO1 biofilm cells, improved bacterial flagellar motility, and increased the rhamnolipid content, contributing to the dispersion of biofilms. Our study provides new insight into the development of CRAMP as a potentially effective antibiofilm dispersant.}, } @article {pmid36208511, year = {2022}, author = {Tabraiz, S and Aiswarya, NM and Taneja, H and Narayanan, RA and Ahmed, A}, title = {Biofilm-based simultaneous nitrification, denitrification, and phosphorous uptake in wastewater by Neurospora discreta.}, journal = {Journal of environmental management}, volume = {324}, number = {}, pages = {116363}, doi = {10.1016/j.jenvman.2022.116363}, pmid = {36208511}, issn = {1095-8630}, mesh = {*Nitrification ; *Wastewater ; Denitrification ; Waste Disposal, Fluid ; Bioreactors/microbiology ; Phosphorus/metabolism ; Nitrogen ; Biofilms ; Carbon ; }, abstract = {Biological removal of nitrogen and phosphorous from wastewater conventionally involves multiple processing steps to satisfy the differing oxygen requirements of the microbial species involved. In this work, simultaneous nitrification, denitrification, and phosphorous removal from synthetic wastewater were achieved by the fungus Neurospora discreta in a single-step, biofilm-based, aerobic process. The concentrations of carbon, nitrogen, and phosphorous in the synthetic wastewater were systematically varied to investigate their effects on nutrient removal rates and biofilm properties. Biofilm growth was significantly (p < 0.05) affected by carbon and nitrogen, but not by phosphorous concentration. Scanning electron microscopy revealed the effects of nutrients on biofilm microstructure, which in turn correlated with nutrient removal efficiencies. The carbohydrate and protein content in the biofilm matrix decreased with increasing carbon and nitrogen concentrations but increased with increasing phosphorous concentration in the wastewater. High removal efficiencies of carbon (96%), ammonium (86%), nitrate (100%), and phosphorus (82%) were achieved under varying nutrient conditions. Interestingly, decreasing the phosphorus concentration increased the nitrification and denitrification rates, and decreasing the nitrogen concentration increased the phosphorus removal rates significantly (p < 0.05). Correlations between biofilm properties and nutrient removal rates were also evaluated in this study.}, } @article {pmid36208141, year = {2023}, author = {Li, KL and Miranda, DZ and Cleare, LG and Akbar, NA and Friedman, JM and Draganski, A and Nosanchuk, JD and Abuzeid, WM}, title = {Nitric oxide-generating microparticles: An in vitro evaluation of anti-biofilm efficacy and sinonasal epithelial cell cytotoxicity.}, journal = {International forum of allergy & rhinology}, volume = {13}, number = {5}, pages = {954-957}, doi = {10.1002/alr.23096}, pmid = {36208141}, issn = {2042-6984}, mesh = {Humans ; *Nitric Oxide ; *Anti-Bacterial Agents ; Biofilms ; Pseudomonas aeruginosa ; }, } @article {pmid36206686, year = {2022}, author = {Wu, X and Wang, C and Wang, D and Huang, YX and Yuan, S and Meng, F}, title = {Simultaneous methanogenesis and denitrification coupled with nitrifying biofilm for high-strength wastewater treatment: Performance and microbial mechanisms.}, journal = {Water research}, volume = {225}, number = {}, pages = {119163}, doi = {10.1016/j.watres.2022.119163}, pmid = {36206686}, issn = {1879-2448}, mesh = {*Wastewater/analysis ; Denitrification ; Biofilms ; Ammonia/analysis ; Bioreactors/microbiology ; Waste Disposal, Fluid ; Nitrification ; Nitrogen/analysis ; Bacteria ; *Ammonium Compounds/analysis ; }, abstract = {A combined system consisting of an upflow blanket filter (UBF) and a moving-bed biofilm reactor (MBBR) was developed for the simultaneous removal of organic matters and ammonia from high-strength wastewater. With a constant COD of approximately 2000 mg/L and ammonium nitrogen in a series of concentrations (e.g., 50, 200 and 400 mg/L in stages I to III) of the influent wastewater, the removal efficiencies of COD, ammonium nitrogen and total nitrogen reached 96.10%-98.19%, 100%, and 79.12%-82.15%, respectively. With the increase of influent ammonia nitrogen concentration, the specific methanogenic activity of the UBF granules decreased significantly, while the specific denitrification rates of the UBF granules and specific nitrification rates of the MBBR biofilms increased significantly. Microbial community analysis showed that Methanobacterium and Methanosaeta were the dominant methanogens in the UBF granules, while Candidatus Competibacter, Thauera and Acinetobacter were identified as dominant denitrifiers. In addition, nitrifiers were enriched in MBBR biofilms at 11.33% and 13.87% of the average abundance of Nitrosomonas and Nitrospira, respectively, at stage III (influent ammonium at 400 mg/L, COD/NH4[+]-N = 5). The ecological network analysis, including full-networks and sub-networks, indicated that the interactions between methanogens and denitrifiers in the UBF granules were strong when the influent ammonium concentration reached 400 mg/L. No intensive interactions were observed among the functional bacteria in the MBBR biofilms over the entire operation. Overall, this study provides a new strategy for the application and construction of efficient biological processes to achieve simultaneous removal of organic matter and nitrogen for high-strength wastewater treatment.}, } @article {pmid36206344, year = {2022}, author = {Dong, Y and Wang, L and Zhang, Z and Ji, F and Chan, TKF and Yang, H and Chan, CPL and Yang, Z and Chen, Z and Chang, WT and Chan, JYK and Sung, JJY and Zhang, L}, title = {Endoscope-assisted magnetic helical micromachine delivery for biofilm eradication in tympanostomy tube.}, journal = {Science advances}, volume = {8}, number = {40}, pages = {eabq8573}, pmid = {36206344}, issn = {2375-2548}, abstract = {Occlusion of the T-tube (tympanostomy tube) is a common postoperative sequela related to bacterial biofilms. Confronting biofilm-related infections of T-tubes, maneuverable and effective treatments are still challenging presently. Here, we propose an endoscopy-assisted treatment procedure based on the wobbling Fe2O3 helical micromachine (HMM) with peroxidase-mimicking activity. Different from the ideal corkscrew motion, the Fe2O3 HMM applies a wobbling motion in the tube, inducing stronger mechanical force and fluid convections, which not only damages the biofilm occlusion into debris quickly but also enhances the catalytic generation and diffusion of reactive oxygen species (ROS) for killing bacteria cells. Moreover, the treatment procedure, which integrated the delivery, actuation, and retrieval of Fe2O3 HMM, was validated in the T-tube implanted in a human cadaver ex vivo. It enables the visual operation with ease and is gentle to the tympanic membrane and ossicles, which is promising in the clinical application.}, } @article {pmid36204628, year = {2022}, author = {Butement, JT and Noel, DJ and Bryant, CA and Wilks, SA and Eason, RW}, title = {A light-guiding urinary catheter for the inhibition of Proteus mirabilis biofilm formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {995200}, pmid = {36204628}, issn = {1664-302X}, abstract = {Catheter-associated urinary tract infection (CAUTI) is a leading cause of hospital-acquired infections worldwide causing debilitating illness for patients as well as a significant financial and treatment burden on health services. CAUTI is linked with the build-up of biofilms on catheter surfaces which act as a reservoir for infection. Additionally, urease-producing bacteria such as Gram-negative Proteus mirabilis (PM), can form crystalline biofilms which encrust catheter surfaces ultimately leading to blockages which require immediate removal of the catheter. Currently there are limited treatments available to prevent the formation of biofilms by PM as well as other urinary tract infection causing bacteria. A novel concept for a light-guiding urinary catheter is presented where a silicone elastomer waveguide incorporated along the length of the catheter is used to irradiate the catheter surfaces with antimicrobial blue light (405 nm) to prevent biofilm formation in situ. The prototype device is mass producible while also easy to fabricate in a lab setting for research studies. The inhibitory effect of blue light on PM biofilm formation over a range of irradiances is described for the first time showing an LD90 at 192-345 J/cm[2] and total inhibition at 1,700 J/cm[2] In vitro studies show that the light-guiding catheter (LGC) prototypes exhibit a 98% inhibition in PM biofilm formation inside the catheter lumen at an average estimated irradiance of 30-50 mW/cm[2] (324-540 J/cm[2] fluence) showing that the concept is highly effective, promising to be a powerful and economical antimicrobial approach to prevent catheter associated biofilm development and blockage.}, } @article {pmid36204611, year = {2022}, author = {Gannesen, AV and Ziganshin, RH and Zdorovenko, EL and Klimko, AI and Ianutsevich, EA and Danilova, OA and Tereshina, VM and Gorbachevskii, MV and Ovcharova, MA and Nevolina, ED and Martyanov, SV and Shashkov, AS and Dmitrenok, AS and Novikov, AA and Zhurina, MV and Botchkova, EA and Toukach, PV and Plakunov, VK}, title = {Epinephrine extensively changes the biofilm matrix composition in Micrococcus luteus C01 isolated from human skin.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {1003942}, pmid = {36204611}, issn = {1664-302X}, abstract = {The importance of the impact of human hormones on commensal microbiota and microbial biofilms is established in lots of studies. In the present investigation, we continued and extended the research of epinephrine effects on the skin commensal Micrococcus luteus C01 and its biofilms, and also the matrix changes during the biofilm growth. Epinephrine in concentration 4.9 × 10[-9] M which is close to normal blood plasma level increased the amount of polysaccharides and extracellular DNA in the matrix, changed extensively its protein, lipid and polysaccharide composition. The Ef-Tu factor was one of the most abundant proteins in the matrix and its amount increased in the presence of the hormone. One of the glucose-mannose polysaccharide was absent in the matrix in presence of epinephrine after 24 h of incubation. The matrix phospholipids were also eradicated by the addition of the hormone. Hence, epinephrine has a great impact on the M. luteus biofilms and their matrix composition, and this fact opens wide perspectives for the future research.}, } @article {pmid36204461, year = {2022}, author = {Kurniawan, A and Ulfa, SM and Chamidah, C}, title = {The Biosorption of Copper(II) Using a Natural Biofilm Formed on the Stones from the Metro River, Malang City, Indonesia.}, journal = {International journal of microbiology}, volume = {2022}, number = {}, pages = {9975333}, pmid = {36204461}, issn = {1687-918X}, abstract = {Biofilm is the predominant habitat of microbes in aquatic ecosystems. Microhabitat inside the biofilm matrix is a nutrient-rich environment promoted by the adsorption of nutrient ions from the surrounding water. Biofilms can not only adsorb ions that are nutrients but also other ions, such as heavy metals. The ability of biofilm to attract and retain heavy metals, such as copper(II), makes biofilms a promising biosorbent for water pollution treatment. The present study analyzes the characteristics of copper(II) adsorption by biofilms naturally formed in the river. The biofilms used in this study grow naturally on the stones in the Metro River in Malang City, Indonesia. Methods to analyze the adsorption characteristics of copper(II) by biofilms were kinetics of the adsorption and adsorption isotherm. The maximum adsorption amount and the adsorption equilibrium constant were calculated using a variant of the Langmuir isotherm model. In addition, the presence of the functional groups as suggested binding sites in biofilm polymers was investigated using the Fourier transform infrared (FTIR) analysis. The results indicate that copper(II)'s adsorption to the biofilm is a physicochemical process. The adsorption of copper(II) is fitted well with the Langmuir isotherm model, suggesting that the adsorption of copper(II) to a biofilm is due to the interaction between the adsorption sites on the biofilm and the ions. The biofilm's maximum absorption capacity for copper(II) is calculated to be 2.14 mg/wet-g of biofilm, with the equilibrium rate constant at 0.05 L/mg. Therefore, the biofilms on the stones from river can be a promising biosorbent of copper(II) pollution in aquatic ecosystems.}, } @article {pmid36203356, year = {2022}, author = {Yuan, B and Zhou, X and Li, Y and Zhao, Y and Xue, M and Guo, Q and Zheng, G and Chen, X and Lin, H and Guo, X}, title = {Black-Phosphorus-Nanosheet-Reinforced Coating of Implants for Sequential Biofilm Ablation and Bone Fracture Healing Acceleration.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {41}, pages = {47036-47051}, doi = {10.1021/acsami.2c13566}, pmid = {36203356}, issn = {1944-8252}, mesh = {*Fracture Healing ; *Phosphorus/pharmacology ; Durapatite/pharmacology ; Osteogenesis ; Biofilms ; Acceleration ; Anti-Bacterial Agents/pharmacology ; Coated Materials, Biocompatible/pharmacology ; Titanium/pharmacology ; }, abstract = {Incurable implant-related infection may cause catastrophic consequences due to the existence of a biofilm that resists the infiltration of host immune cells and antibiotics. Innovative approaches inspired by nanomedicine, e.g., engineering innovative multifunctional bionic coating systems on the surface of implants, are becoming increasingly attractive. Herein, 2D black phosphorus nanosheets (BPs) were loaded onto a hydroxyapatite (HA)-coated metal implant to construct a BPs@HA composite coating. With its photothermal conversion effect and in situ biomineralization, the BPs@HA coating shows excellent performances in ablating the bacterial biofilm and accelerating fracture healing, which were verified through both in vitro and in vivo studies. Moreover, differentially expressed genes of bone formation and bone mesenchymal stem cells (BMSCs) regulated by the BPs@HA coating were identified using absolute quantitative transcriptome sequencing followed by the screening of gene differential expressions. A functional enrichment analysis reveals that the expression of core markers related to BMSC differentiation and bone formation could be effectively regulated by BPs through a metabolism-related pathway. This work not only illustrates the great potential in clinical application of the BPs@HA composite coating to eliminate bacteria and accelerate bone fracture healing but also contributes to an understanding of the underlying molecular mechanism of osteogenesis physiological function regulation based on an analysis of absolute quantitative transcriptome sequencing.}, } @article {pmid36202349, year = {2022}, author = {Suo, A and Hua, Z and Wu, C and Fan, G and Li, T and Cong, K}, title = {Effects of ginkgolic acid(C15:1)on biofilm formation, pathogenic factor production and quorum sensing of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {173}, number = {Pt A}, pages = {105813}, doi = {10.1016/j.micpath.2022.105813}, pmid = {36202349}, issn = {1096-1208}, mesh = {*Quorum Sensing ; *Pseudomonas aeruginosa ; Virulence Factors ; Anti-Bacterial Agents/pharmacology/metabolism ; Biofilms ; Bacterial Proteins/genetics/pharmacology ; }, abstract = {To complete the investigation of the bacterial inhibitory activity of ginkgolic acid (GA), the quorum sensing activity of GA was investigated to assess the potential of ginkgo biloba exocarp for the production of quorum sensing inhibitor. The effect of GA (C15:1) on the growth and secondary metabolism of p. aeruginosa PAO1 were tested. The results showed that GA (C15:1) had no effect on the growth of p. aeruginosa PAO1, and that GA (C15:1) was able to inhibit the formation of quorum sensing dependent virulence factors, but promoted the formation of biofilms. Finally, the above experimental results were verified by LasR-GFP, RhlR-GFP system and fluorescence quantitative PCR. These results suggested that GA (C15:1) was capable of modulating the quorum sensing system of p. aeruginosa PAO1 and possessed potential as an anti-virulence factor drug, but is not suitable for development as a broad-spectrum biofilm inhibitor.}, } @article {pmid36201672, year = {2022}, author = {Zhou, J and Wu, C and Pang, S and Yang, L and Yao, M and Li, X and Xia, S and Rittmann, BE}, title = {Dissimilatory and Cytoplasmic Antimonate Reductions in a Hydrogen-Based Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {56}, number = {20}, pages = {14808-14816}, doi = {10.1021/acs.est.2c04939}, pmid = {36201672}, issn = {1520-5851}, mesh = {*Arsenate Reductases ; Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; *Hydrogen ; Iron ; }, abstract = {A hydrogen-based membrane biofilm reactor (H2-MBfR) was operated to investigate the bioreduction of antimonate [Sb(V)] in terms of Sb(V) removal, the fate of Sb, and the pathways of reduction metabolism. The MBfR achieved up to 80% Sb(V) removal and an Sb(V) removal flux of 0.55 g/m[2]·day. Sb(V) was reduced to Sb(III), which mainly formed Sb2O3 precipitates in the biofilm matrix, although some Sb(III) was retained intracellularly. High Sb(V) loading caused stress that deteriorated performance that was not recovered when the high Sb(V) loading was removed. The biofilm community consisted of DSbRB (dissimilatory Sb-reduction bacteria), SbRB (Sb-resistant bacteria), and DIRB (dissimilatory iron-reducing bacteria). Dissimilatory antimonate reduction, mediated by the respiratory arsenate reductase ArrAB, was the main reduction route, but respiratory reduction coexisted with cytoplasmic Sb(V)-reduction mediated by arsenate reductase ArsC. Increasing Sb(V) loading caused stress that led to increases in the expression of arsC gene and intracellular accumulation of Sb(III). By illuminating the roles of the dissimilatory and cytoplasmic Sb(V) reduction mechanism in the biofilms of the H2-MBfR, this study reveals that the Sb(V) loading should be controlled to avoid stress that deteriorates Sb(V) reduction.}, } @article {pmid36201343, year = {2022}, author = {Fallon, M and Kennedy, S and Daniels, S and Humphreys, H}, title = {Technologies to decontaminate bacterial biofilm on hospital surfaces: a potential new role for cold plasma?.}, journal = {Journal of medical microbiology}, volume = {71}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001582}, pmid = {36201343}, issn = {1473-5644}, mesh = {Bacteria ; Biofilms ; *Cross Infection/microbiology ; Decontamination ; Hospitals ; Humans ; Hydrogen Peroxide/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Viability ; Oxygen ; *Plasma Gases/pharmacology ; }, abstract = {Healthcare-associated infections (HCAIs) are a major challenge and the near patient surface is important in harbouring causes such as methicillin-resistant Staphylococcus aureus (MRSA) and Clostridioides difficile. Current approaches to decontamination are sub-optimal and many studies have demonstrated that microbial causes of HCAIs may persist with onward transmission. This may be due to the capacity of these microbes to survive in biofilms on surfaces. New technologies to enhance hospital decontamination may have a role in addressing this challenge. We have reviewed current technologies such as UV light and hydrogen peroxide and also assessed the potential use of cold atmospheric pressure plasma (CAPP) in surface decontamination. The antimicrobial mechanisms of CAPP are not fully understood but the production of reactive oxygen and other species is believed to be important. CAPP systems have been shown to partially or completely remove a variety of biofilms including those caused by Candida albicans, and multi-drug-resistant bacteria such as MRSA. There are some studies that suggest promise for CAPP in the challenge of surface decontamination in the healthcare setting. However, further work is required to define better the mechanism of action. We need to know what surfaces are most amenable to treatment, how microbial components and the maturity of biofilms may affect successful treatment, and how would CAPP be used in the clinical setting.}, } @article {pmid36201337, year = {2022}, author = {Silva-de-Jesus, AC and Ferrari, RG and Panzenhagen, P and Conte-Junior, CA}, title = {Staphylococcus aureus biofilm: the role in disseminating antimicrobial resistance over the meat chain.}, journal = {Microbiology (Reading, England)}, volume = {168}, number = {10}, pages = {}, doi = {10.1099/mic.0.001245}, pmid = {36201337}, issn = {1465-2080}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Drug Resistance, Bacterial/genetics ; Female ; Meat ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections/epidemiology ; Staphylococcus ; Staphylococcus aureus/genetics ; }, abstract = {Staphylococcus aureus is responsible for severe skin and respiratory infections and food poisoning, resulting in hospitalizations and high morbidity worldwide. Staphylococci have extensive virulence mechanisms and antimicrobial resistance that pose a global challenge to contain the spread of infectious outbreaks. Antimicrobials are used as growth promoters, and for prevention and treatment of infections in animals that provide us with food. The improvement of animal health is undeniable, but the selection of multidrug-resistant strains that can spread resistance genes among microorganisms is undesirable. The administration of sublethal doses of antimicrobials in farm animals causes stress to Staphylococci inducing the formation of a complex extracellular polymeric structure called biofilm. Such a structure may favor the persistence of infection by disseminating antimicrobial-resistant strains that can be consumed in contaminated food of animal origin. In ruminant mastitis and hospitals, the potential of the biofilm structure in the persistence of infections, especially those caused by S. aureus, has already been demonstrated, as well as its role as a source of resistant genes. In the meat production chain, the potential for persistent contamination by biofilm structure is evidently a worrying health risk . This review brings together studies demonstrating that biofilm production facilitates the exchange of mobile genetic elements and random mutations in S. aureus strains within the structure. This contributes to the emergence of more resistant clonal complexes and, with biofilm support, persists in the meat production chain.}, } @article {pmid36199677, year = {2022}, author = {Song, NN and Qian, GY and Zheng, HL and Zhou, XW and Mei, H and Li, DM and Li, XF and Liu, WD}, title = {Biofilm Alterations on the Stepwise Acquisition of Fluconazole-resistant Candida Albicans Isolates.}, journal = {International journal of dermatology and venereology}, volume = {5}, number = {3}, pages = {132-139}, pmid = {36199677}, issn = {2641-8746}, abstract = {UNLABELLED: By assessing and comparing the phenotypic changes on the stepwise acquisition of fluconazole resistant Candida albicans isolates, we could find and describe the relationship between drug resistance and biofilm formation ability in a series of clonal strains.

METHODS: We performed antifungal susceptibility of five drugs (fluconazole, itraconazole, voriconazole, caspofungin and amphotericin B) to further verify the antifungal activity of the six isolates in vitro. Then we combined hyphal formation assay, cell surface hydrophobicity test positively related to adherence ability, and biofilm assays in vitro to observe and compare the phenotypic characteristics of our six clonal strains.

RESULTS: Biofilm capability is enhanced for four drug- intermediate strains, whereas the initial susceptible strain and the final resistant strain are both poor in adherence, hyphal growth and biofilm formation.

CONCLUSIONS: It was suggested that the biofilm formation ability were not absolutely related to the degree of fluconazole resistance.}, } @article {pmid36198620, year = {2022}, author = {Sahoo, A and Swain, SS and Panda, SK and Hussain, T and Panda, M and Rodrigues, CF}, title = {In Silico Identification of Potential Insect Peptides against Biofilm-Producing Staphylococcus aureus.}, journal = {Chemistry & biodiversity}, volume = {19}, number = {10}, pages = {e202200494}, doi = {10.1002/cbdv.202200494}, pmid = {36198620}, issn = {1612-1880}, support = {1981611009//Miss Alaka Sahoo/ ; 3/1/3/PDF(21)/HRD-2019-2//ICMR-Post Doctoral Fellowship/ ; }, mesh = {Animals ; *Staphylococcus aureus ; Molecular Docking Simulation ; Protein C/pharmacology/therapeutic use ; Aspartic Acid/pharmacology/therapeutic use ; *Staphylococcal Infections/drug therapy ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Defensins/pharmacology/therapeutic use ; Insecta ; Serine/pharmacology/therapeutic use ; Microbial Sensitivity Tests ; }, abstract = {Biofilm-producing Staphylococcus aureus (SA) strains are frequently found in medical environments, from surgical/ wound sites, medical devices. These biofilms reduce the efficacy of applied antibiotics during the treatment of several infections, such as cystic fibrosis, endocarditis, or urinary tract infections. Thus, the development of potential therapeutic agents to destroy the extra protective biofilm layers or to inhibit the biofilm-producing enzymes is urgently needed. Advanced and cost-effective bioinformatics tools are advantageous in locating and speeding up the selection of antibiofilm candidates. Based on the potential drug characteristics, we have selected one-hundred thirty-three antibacterial peptides derived from insects to assess for their antibiofilm potency via molecular docking against five putative biofilm formation and regulated target enzymes: the staphylococcal accessory regulator A or SarA (PDB ID: 2FRH), 4,4'-diapophytoene synthase or CrtM (PDB ID: 2ZCQ), clumping factor A or ClfA (PDB ID: 1N67) and serine-aspartate repeat protein C or SdrC (PDB ID: 6LXH) and sortase A or SrtA (PDB ID: 1T2W) of SA bacterium. In this study, molecular docking was performed using HPEPDOCK and HDOCK servers, and molecular interactions were examined using BIOVIA Discovery Studio Visualizer-2019. The docking score (kcal/mol) range of five promising antibiofilm peptides against five targets was recorded as follows: diptericin A (-215.52 to -303.31), defensin (-201.11 to -301.92), imcroporin (-212.08 to -287.64), mucroporin (-228.72 to -286.76), apidaecin II (-203.90 to -280.20). Among these five, imcroporin and mucroporin were 13 % each, while defensin contained only 1 % of positive net charged residues (Arg+Lys) projected through ProtParam and NetWheels tools. Similarly, imcroporin, mucroporin and apidaecin II were 50 %, while defensin carried 21.05 % of hydrophobic residues predicted by the tool PEPTIDE. 2.0. Most of the peptides exhibited potential characteristics to inhibit S. aureus-biofilm formation via disrupting the cell membrane and cytoplasmic integrity. In summary, the proposed hypothesis can be considered a cost-effective platform for selecting the most promising bioactive drug candidates within a limited timeframe with a greater chance of success in experimental and clinical studies.}, } @article {pmid36198352, year = {2023}, author = {Wang, X and Chen, S and Bi, X and Chen, N and Yang, T and Wang, L and Maletskyi, Z and Ratnaweera, H}, title = {Morphological image analysis of biofilm evolution with quantitative analysis in a moving bed biofilm reactor.}, journal = {The Science of the total environment}, volume = {856}, number = {Pt 2}, pages = {159199}, doi = {10.1016/j.scitotenv.2022.159199}, pmid = {36198352}, issn = {1879-1026}, mesh = {*Biofilms ; *Bioreactors ; Biomass ; Waste Disposal, Fluid/methods ; }, abstract = {The quantitative analysis of biomass is essential for the research and application of moving bed biofilm reactors (MBBRs). However, the difficulty in measuring the attached growing biomass hinders the quantitative analysis of biofilm processes. In this study, a pilot-scale MBBR system was established to investigate biofilm evolution. The quantity of active heterotrophic and autotrophic biomass was measured throughout the entire culturing process. The total active biomass reached 250 mg COD/m[2] when the biofilm attachment and detachment were balanced, and the corresponding autotrophic biomass contributes to as high as 17 % of the total biomass. Furthermore, quantitative image analysis was performed to obtain the thickness and morphological data of the biofilm evolution. Multivariate regression models were constructed based on the morphological data, which provided satisfactory prediction accuracy for the biofilm thickness and maturation. The most suitable carrier spots for biomass quantification and biofilm maturation were suggested. This work provided the life-cycle information of biofilm quantity and morphology of the MBBR, which contributes to the quantitative understanding of biofilm evolution at MBBRs.}, } @article {pmid36198099, year = {2022}, author = {Malazarte, J and Muotka, T and Jyväsjärvi, J and Lehosmaa, K and Nyberg, J and Huttunen, KL}, title = {Bacterial communities in a subarctic stream network: Spatial and seasonal patterns of benthic biofilm and bacterioplankton.}, journal = {Molecular ecology}, volume = {31}, number = {24}, pages = {6649-6663}, pmid = {36198099}, issn = {1365-294X}, mesh = {*Plankton/genetics ; RNA, Ribosomal, 16S/genetics ; Phylogeny ; Seasons ; *Bacteria/genetics ; Aquatic Organisms ; Biofilms ; Water ; Soil ; Ecosystem ; }, abstract = {Water-column bacterial communities are assembled by different mechanisms at different stream network positions, with headwater communities being controlled by mass effects (advection of bacteria from terrestrial soils) while downstream communities are mainly driven by environmental sorting. Conversely, benthic biofilms are colonized largely by the same set of taxa across the entire network. However, direct comparisons of biofilm and bacterioplankton communities along whole stream networks are rare. We used 16S rRNA gene amplicon sequencing to explore the spatiotemporal variability of benthic biofilm (2 weeks old vs. mature biofilm) and water-column communities at different network positions of a subarctic stream from early summer to late autumn. Amplicon sequence variant (ASV) richness of mature biofilm was about 2.5 times higher than that of early biofilm, yet the pattern of seasonality was the same, with the highest richness in midsummer. Biofilm bacterial richness was unrelated to network position whereas bacterioplankton diversity was negatively related to water residence time and distance from the source. This pattern of decreasing diversity along the network was strongest around midsummer and diminished greatly as water level increased towards autumn. Biofilm communities were phylogenetically clustered at all network positions while bacterioplankton assemblages were phylogenetically clustered only at the most downstream site. Both early and mature biofilm communities already differed significantly between upstream (1st order) and midstream (2nd order) sections. Network position was also related to variation in bacterioplankton communities, with upstream sites harbouring substantially more unique taxa (44% of all upstream taxa) than midstream (20%) or downstream (8%) sites. Some of the taxa that were dominant in downstream sections were already present in the upmost headwaters, and even in riparian soils, where they were very rare (relative abundance <0.01%). These patterns in species diversity and taxonomic and phylogenetic community composition of the riverine bacterial metacommunity were particularly strong for water-column communities, whereas both early and mature biofilm exhibited weaker spatial patterns. Our study demonstrated the benefits of studying bacterioplankton and biofilm communities simultaneously to allow testing of ecological hypotheses about biodiversity patterns in freshwater bacteria.}, } @article {pmid36195408, year = {2022}, author = {Martínez-Meléndez, A and Morfin-Otero, R and Villarreal-Treviño, L and Baines, SD and Camacho-Ortíz, A and Garza-González, E}, title = {Analysis of biofilm production and expression of adhesion structures of circulating Clostridioides difficile strains from Mexico.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {40}, number = {8}, pages = {445-448}, doi = {10.1016/j.eimce.2021.01.008}, pmid = {36195408}, issn = {2529-993X}, mesh = {Anti-Bacterial Agents ; Bacterial Proteins/genetics ; Biofilms ; Clostridioides ; *Clostridioides difficile/genetics ; Endopeptidase K ; Gentian Violet ; Mexico ; }, abstract = {INTRODUCTION: Clostridioides difficile biofilms are believed to protect the pathogen from antibiotics, in addition to potentially contributing to recurrent infections.

METHODOLOGY: Biofilm production of 102 C. difficile isolates was determined using the crystal violet staining technique, and detachment assays were performed. The expression levels of cwp84 and slpA genes were evaluated by real-time PCR on selected isolates.

RESULTS: More than 70% of isolates (75/102) were strong biofilm producers, and the highest detachment of biofilm was achieved with the proteinase K treatment (>90%). The overall mean expression of cwp84 was higher in RT027 than in RT001 (p=0.003); among strong biofilm-producing strains, the slpA expression was lower in RT027 than in RT001 (p<0.000).

CONCLUSIONS: Proteins seem to have an important role in the biofilm's initial adherence and maturation. slpA and cwp84 are differentially expressed by C. difficile ribotype and biofilm production level.}, } @article {pmid36195405, year = {2022}, author = {Alonso, B and Pérez-Granda, MJ and Latorre, MC and Sánchez-Carrillo, C and Bouza, E and Muñoz, P and Guembe, M}, title = {Production of biofilm by Staphylococcus aureus: Association with infective endocarditis?.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {40}, number = {8}, pages = {418-422}, doi = {10.1016/j.eimce.2021.03.009}, pmid = {36195405}, issn = {2529-993X}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Bacteremia/drug therapy ; Biofilms ; *Endocarditis ; *Endocarditis, Bacterial/diagnosis ; Gentian Violet ; Humans ; *Staphylococcal Infections/complications/drug therapy ; Staphylococcus aureus ; }, abstract = {OBJECTIVES: Staphylococcus aureus is a well-known biofilm-producing pathogen that is capable of causing chronic infections owing to its ability to resist antibiotic treatment and obstruct the immune response. However, the possible association between high biofilm production and infective endocarditis (IE) has not been assessed. Our objective was to compare production of biofilm by S. aureus strains isolated from patients with bacteremia and IE, catheter-related bloodstream infection (C-RBSI), or non-device associated bacteremia.

METHODS: We isolated 260 S. aureus strains from the blood of patients with bacteremia who were diagnosed during hospital admission between 2012 and 2015. Patients were divided into 3 groups according to whether they had IE, C-RBSI, or non-device associated bacteremia. Biofilm production was measured in terms of biomass and metabolic activity using the crystal violet and XTT assays, respectively. High biomass and metabolic activity rates (based on tertile ranks classification) were compared between the 3 groups.

RESULTS: The high biomass and metabolic activity rates of each group were 41.9% and 37.2% for IE, 32.5% and 35.0%, for C-RBSI, and 29.0% and 33.3% for non-device associated bacteremia (p=0.325 and p=0.885, respectively).

CONCLUSIONS: High biomass and metabolic activity levels for S. aureus isolates from IE were similar to those of S. aureus isolates from C-RBSI or non-device associated bacteremia.}, } @article {pmid36195404, year = {2022}, author = {Lora-Tamayo, J and Meléndez-Carmona, MÁ}, title = {The clinical meaning of biofilm formation ability: The importance of context.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {40}, number = {8}, pages = {415-417}, doi = {10.1016/j.eimce.2022.02.014}, pmid = {36195404}, issn = {2529-993X}, mesh = {*Biofilms ; *Terminology as Topic ; }, } @article {pmid36192897, year = {2022}, author = {Wang, Z and Ma, Y and Li, Z and Wang, Y and Liu, Y and Dong, Q}, title = {Characterization of Listeria monocytogenes biofilm formation kinetics and biofilm transfer to cantaloupe surfaces.}, journal = {Food research international (Ottawa, Ont.)}, volume = {161}, number = {}, pages = {111839}, doi = {10.1016/j.foodres.2022.111839}, pmid = {36192897}, issn = {1873-7145}, mesh = {Biofilms ; *Cucumis melo ; Extracellular Polymeric Substance Matrix ; *Listeria monocytogenes ; Xylenes ; }, abstract = {Listeria monocytogenes biofilm is a consistent source of cross-contamination, both in housing storage and food processing environments. This study monitored the dynamic process of L. monocytogenes ST9 and ST87 biofilms, as well as their cross-contamination behaviors at various stages of formation. Scanning Electron Microscopy (SEM) captured the honeycomb-like structures and extracellular polymeric substances (EPS) during the biofilm formation. Confocal Laser Scanning Microscopy (CLSM) images illustrated that the ST87 strain formed a closed knitted chains network later than the ST9 strain. Moreover, structural parameters including bio-volume, mean thickness, porosity, and roughness could quantified the spatio-temporal differences of the biofilms. The transfer rates of biofilm cells to cantaloupes with the single contact had no significant difference at the initial adhesion, maturation, and dispersion stage (p > 0.05). Notably, the biofilm cells remained on the glass coupons when transferred to ten cantaloupe slices, indicating that biofilm cells transferred through cohesive failure. Meanwhile, the Logistic model could describe the transfer law of biofilm cells at different formation stages, as evaluated by Root Mean Square Error (RMSE) and R[2]adj. Additionally, the transfer rates were positively correlated with the hydrophobicity of L. monocytogenes ST87 biofilm cells measured by xylene. However, when the hydrophobicity of n-hexadecane was measured, the correlation was negative. This study illustrated the spatial and temporal differences during L. monocytogenes biofilms formation, and the transfer and residual of biofilm cells after a single and ten successive contacts at the specific stages. Our findings help in the quantitative microbiological risk assessment of fresh produce.}, } @article {pmid36192889, year = {2022}, author = {Yao, S and Zhou, R and Jin, Y and Huang, J and Qin, J and Wu, C}, title = {Formation of biofilm changed the responses of Tetragenococcus halophilus to ethanol stress revealed by transcriptomic and proteomic analyses.}, journal = {Food research international (Ottawa, Ont.)}, volume = {161}, number = {}, pages = {111817}, doi = {10.1016/j.foodres.2022.111817}, pmid = {36192889}, issn = {1873-7145}, mesh = {Biofilms ; Citrates ; Enterococcaceae ; Ethanol ; Fatty Acids ; Lactic Acid ; Malates ; Peptidoglycan/genetics ; *Proteomics ; Spectroscopy, Fourier Transform Infrared ; *Transcriptome ; Tryptophan ; }, abstract = {Biofilms were found to promote the survival of Tetragenococcus halophilus, a functional halophilic lactic acid bacterium in the production of high-salt fermented foods under various environmental stresses including ethanol stress. Here, a comprehensive exploration of the response of T.halophilus biofilms and planktonic cells to ethanol stress was performed. Biofilms showed an ability to reduce death and damage of cell membrane and wall under 12% ethanol stress The formation of biofilm changed the characteristic of Fourier transformed infrared spectroscopy (FT-IR). RNA-seq technology and iTRAQ technology revealed the differential expression of genes and proteins in biofilm and planktonic cells with or without ethanol treatment. The differentially expressed genes and proteins played positive roles in the biosynthesis of polysaccharides, proteins, and DNA, benefitting biofilm matrix production. The shelter provided by biofilms and the differential expression of genes and proteins involved in citrate formation, malate utilization, and the biosynthesis of tryptophan, fatty acid, lipoteichoic acid, and peptidoglycan might contribute to the stress tolerance of biofilm cells together. Results presented in this study may contribute to our understanding of biofilm formation by T. halophilus and the roles of bacterial biofilm in stress tolerance.}, } @article {pmid36192618, year = {2023}, author = {Chatterjee, S and Das, S and Paul, P and Chakraborty, P and Sarkar, S and Das, A and Tribedi, P}, title = {Synergistic interaction of cuminaldehyde and tobramycin: a potential strategy for the efficient management of biofilm caused by Pseudomonas aeruginosa.}, journal = {Folia microbiologica}, volume = {68}, number = {1}, pages = {151-163}, pmid = {36192618}, issn = {1874-9356}, mesh = {Humans ; *Tobramycin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Pseudomonas aeruginosa ; Biofilms ; Microbial Sensitivity Tests ; Drug Synergism ; *Pseudomonas Infections ; }, abstract = {Pseudomonas aeruginosa, an opportunistic pathogen, has been found to cause several chronic and acute infections in human. Moreover, it often shows drug-tolerance and poses a severe threat to public healthcare through biofilm formation. In this scenario, two molecules, namely, cuminaldehyde and tobramycin, were used separately and in combination for the efficient management of biofilm challenge. The minimum inhibitory concentration (MIC) of cuminaldehyde and tobramycin was found to be 150 µg/mL and 1 µg/mL, respectively, against Pseudomonas aeruginosa. The checkerboard assay revealed that the fractional inhibitory concentration (FIC) index of cuminaldehyde and tobramycin was 0.36 suggesting a synergistic association between them. The sub-MIC dose of cuminaldehyde (60 µg/mL) or tobramycin (0.06 µg/mL) individually did not show any effect on the microbial growth curve. However, the same combinations could affect microbial growth curve of Pseudomonas aeruginosa efficiently. In connection to biofilm management, it was observed that the synergistic interaction between cuminaldehyde and tobramycin could inhibit biofilm formation more efficiently than their single use (p < 0.01). Further investigation revealed that the combinations of cuminaldehyde and tobramycin could generate reactive oxygen species (ROS) that resulted in the increase of membrane permeability of bacterial cells leading to the efficient inhibition of microbial biofilm formation. Besides, the synergistic interaction between cuminaldehyde (20 µg/mL) and tobramycin (0.03 µg/mL) also showed significant biofilm dispersal of the test microorganism (p < 0.01). Hence, the results suggested that synergistic action of cuminaldehyde and tobramycin could be applied for the efficient management of microbial biofilm.}, } @article {pmid36191798, year = {2022}, author = {Laderriere, V and Morin, S and Eon, M and Fortin, C}, title = {Vulnerability and tolerance to nickel of periphytic biofilm harvested in summer and winter.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {315}, number = {}, pages = {120223}, doi = {10.1016/j.envpol.2022.120223}, pmid = {36191798}, issn = {1873-6424}, mesh = {Biofilms ; Ecosystem ; *Nickel/toxicity ; Seasons ; *Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {Metals are naturally present in freshwater ecosystems but anthropogenic activities like mining operations represent a long-standing concern. Metals released into aquatic environments may affect microbial communities such as periphytic biofilm, which plays a key role as a primary producer in stream ecosystems. Using two 28-day microcosm studies involving two different photoperiods (light/dark cycle of 16/8 vs 8/16), the present study assessed the effects of four increasing nickel (Ni) concentrations (0-6 μM) on two natural biofilm communities collected at different seasons (summer and winter). The two communities were characterized by different structural profiles and showed significant differences in Ni accumulated content for each treatment. For instance, the biofilm metal content was four times higher in the case of summer biofilm at the highest Ni treatment and after 28 days of exposure. Biomarkers examined targeted both heterotrophic and autotrophic organisms. For heterotrophs, the β-glucosidase and β-glucosaminidase showed no marked effects of Ni exposure and were globally similar between the two communities suggesting low toxicity. However, the photosynthetic yield confirmed the toxicity of Ni on autotrophs with maximum inhibition of 81 ± 7% and 60 ± 1% respectively for the summer and winter biofilms. Furthermore, biofilms previously exposed to the highest long-term Ni concentration ([Ni[2+]] = 6 μM) revealed no acute effects in subsequent toxicity based on the PSII yield, suggesting a tolerance acquisition by the phototrophic community. Taken together, the results suggest that the biofilm response to Ni exposure was dependent of the function considered and that descriptors such as biofilm metal content could be seasonally dependent, information of great importance in a context of biomonitoring.}, } @article {pmid36190419, year = {2022}, author = {Park, M and Kim, J and Horn, L and Haan, J and Strickland, A and Lappi, V and Boxrud, D and Hedberg, C and Ryu, S and Jeon, B}, title = {Sugar Modification of Wall Teichoic Acids Determines Serotype-Dependent Strong Biofilm Production in Listeria monocytogenes.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0276922}, pmid = {36190419}, issn = {2165-0497}, mesh = {Humans ; *Listeria monocytogenes/genetics ; Serogroup ; Teichoic Acids ; Phylogeny ; Sugars ; Rhamnose ; Biofilms ; Serotyping ; Food Microbiology ; }, abstract = {Biofilm production is responsible for persistent food contamination by Listeria monocytogenes, threatening food safety and public health. Human infection and food contamination with L. monocytogenes are caused primarily by serotypes 1/2a, 1/2b, and 4b. However, the association of biofilm production with phylogenic lineage and serotype has not yet been fully understood. In this study, we measured the levels of biofilm production in 98 clinical strains of L. monocytogenes at 37°C, 25°C, and 4°C. The phylogenetic clusters grouped by core genome multilocus sequence typing (cgMLST) exhibited association between biofilm production and phylogenetic lineage and serotype. Whereas clusters 1 and 3 consisting of serotype 4b strains exhibited weak biofilm production, clusters 2 (serotype 1/2b) and 4 (serotype 1/2a) were composed of strong biofilm formers. Particularly, cluster 2 (serotype 1/2b) strains exhibited the highest levels of biofilm production at 37°C, and the levels of biofilm production of cluster 4 (serotype 1/2a) strains were significantly elevated at all tested temperatures. Pan-genome analysis identified 22 genes unique to strong biofilm producers, most of which are related to the synthesis and modification of teichoic acids. Notably, a knockout mutation of the rml genes related to the modification of wall teichoic acids with l-rhamnose, which is specific to serogroup 1/2, significantly reduced the level of biofilm production by preventing biofilm maturation. Here, the results of our study show that biofilm production in L. monocytogenes is related to phylogeny and serotype and that the modification of wall teichoic acids with l-rhamnose is responsible for serotype-specific strong biofilm formation in L. monocytogenes. IMPORTANCE Biofilm formation on the surface of foods or food-processing facilities by L. monocytogenes is a serious food safety concern. Here, our data demonstrate that the level of biofilm production differs among serotypes 1/2a, 1/2b, and 4b depending on the temperature. Furthermore, sugar decoration of bacterial cell walls with l-rhamnose is responsible for strong biofilm production in serotypes 1/2a and 1/2b, commonly isolated from foods and listeriosis cases. The findings in this study improve our understanding of the association of biofilm production with phylogenetic lineage and serotype in L. monocytogenes.}, } @article {pmid36190417, year = {2022}, author = {Kim, YG and Lee, JH and Park, S and Khadke, SK and Shim, JJ and Lee, J}, title = {Hydroquinones Including Tetrachlorohydroquinone Inhibit Candida albicans Biofilm Formation by Repressing Hyphae-Related Genes.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0253622}, pmid = {36190417}, issn = {2165-0497}, mesh = {Animals ; Humans ; *Candida albicans/genetics ; *Hyphae/genetics ; Antifungal Agents/pharmacology ; Hydroquinones/pharmacology ; Fluconazole/pharmacology ; Biofilms ; Virulence Factors/genetics ; Caenorhabditis elegans/genetics/microbiology ; }, abstract = {Candida albicans is an opportunistic pathogenic fungus responsible for candidiasis. The pathogen readily forms antifungal agent-resistant biofilms on implanted medical devices or human tissue. Morphologic transition from yeast to filamentous cells and subsequent biofilm formation is a key virulence factor and a prerequisite for biofilm development by C. albicans. We investigated the antibiofilm and antifungal activities of 18 hydroquinones against fluconazole-resistant C. albicans. Tetrachlorohydroquinone (TCHQ) at subinhibitory concentrations (2 to 10 μg/mL) significantly inhibited C. albicans biofilm formation with an MIC of 50 μg/mL, whereas the backbone hydroquinone did not (MIC > 400 μg/mL), and it markedly inhibited cell aggregation and hyphal formation. Transcriptomic analyses showed that TCHQ downregulated the expressions of several hyphae-forming and biofilm-related genes (ALS3, ECE1, HWP1, RBT5, and UME6) but upregulated hyphae- and biofilm-inhibitory genes (IFD6 and YWP1). Furthermore, it prevented C. albicans biofilm development on porcine skin and at concentrations of 20 to 50 μg/mL was nontoxic to the nematode Caenorhabditis elegans and did not adversely affect Brassica rapa seed germination and growth. This study indicates that hydroquinones, particularly TCHQ, diminish the virulence, biofilm formation, and animal tissue adhesion of C. albicans, which suggests hydroquinones should be considered potential candidate antifungal agents against drug-resistant C. albicans strains. IMPORTANCE Persistence in chronic infections by Candida albicans is due to its ability of biofilm formation that endures conventional antifungals and host immune systems. Hence, the inhibition of biofilm formation and virulence characteristics is another mean of addressing infections. This study is a distinctive one since 18 hydroquinone analogues were screened and TCHQ efficiently inhibited the biofilm formation by C. albicans with significantly changed expressional profile of hyphae-forming and biofilm-related genes. The antibiofilm efficacy was confirmed using a porcine skin model and chemical toxicity was investigated using plant seed germination and nematode models. Our findings reveal that TCHQ can efficiently control the C. albicans biofilms and virulence characteristics.}, } @article {pmid36190404, year = {2022}, author = {Palau, M and Muñoz, E and Lujan, E and Larrosa, N and Gomis, X and Márquez, E and Len, O and Almirante, B and Abellà, J and Colominas, S and Gavaldà, J}, title = {In Vitro and In Vivo Antimicrobial Activity of Hypochlorous Acid against Drug-Resistant and Biofilm-Producing Strains.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0236522}, pmid = {36190404}, issn = {2165-0497}, mesh = {Rabbits ; Animals ; *Daptomycin/pharmacology ; Vancomycin/pharmacology ; Hypochlorous Acid/pharmacology ; Saline Solution/pharmacology ; Saccharomyces cerevisiae ; Biofilms ; Staphylococcus epidermidis ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Catheter-Related Infections/drug therapy/microbiology ; *Anti-Infective Agents/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {The aims of this study were as follows. First, we determined the antimicrobial efficacy of hypochlorous acid (HClO) against bacterial, fungal, and yeast strains growing planktonically and growing in biofilms. Second, we sought to compare the activity of the combination of daptomycin and HClO versus those of the antimicrobial agents alone for the treatment of experimental catheter-related Staphylococcus epidermidis infection (CRI) using the antibiotic lock technique (ALT) in a rabbit model. HClO was generated through direct electric current (DC) shots at determined amperages and times. For planktonic susceptibility studies, 1 to 3 DC shots of 2, 5, and 10 mA from 0 to 300 s were applied. A DC shot of 20 mA from 0 to 20 min was applied to biofilm-producing strains. Central venous catheters were inserted into New Zealand White rabbits, inoculated with an S. epidermidis strain, and treated with saline solution or ALT using daptomycin (50 mg/mL), HClO (20 mA for 45 min), or daptomycin plus HClO. One hundred percent of the planktonic bacterial, fungal, and yeast strains were killed by applying one DC shot of 2, 5, and 10 mA, respectively. One DC shot of 20 mA for 20 min was sufficient to eradicate 100% of the tested biofilm-producing strains. Daptomycin plus HClO lock therapy showed the highest activity for experimental CRI with S. epidermidis. HClO could be an effective strategy for treating infections caused by extensively drug-resistant or multidrug-resistant and biofilm-producing strains in medical devices and chronic wounds. The results of the ALT using daptomycin plus HClO may be promising. IMPORTANCE Currently, drug-resistant infections are increasing and there are fewer antibiotics available to treat them. Therefore, there is an urgent need to find new antibiotics and nonantimicrobial strategies to treat these infections. We present a new nonantibiotic strategy based on hypochlorous acid generation to treat long-term catheter-related and chronic wounds infections.}, } @article {pmid36190373, year = {2022}, author = {Di Perri, G and Ferlazzo, G}, title = {Biofilm Development and Approaches to Biofilm Inhibition by Exopolysaccharides.}, journal = {The new microbiologica}, volume = {45}, number = {4}, pages = {227-236}, pmid = {36190373}, issn = {1121-7138}, mesh = {Humans ; *Biofilms ; Bacteria ; *Bacterial Infections ; }, abstract = {Bacteria biofilm consists of microorganisms, accounting for 5-35% of the biofilm volume, and of the extracellular matrix (65-95%), made of water (97%), proteins (2%), polysaccharides (1-2%) and nucleic acids (DNA/RNA, both <1%). The physiology of bacteria in the biofilms entails adaptive changes with expression of genes which are different from those translated in the planktonic state. While most of our applied knowledge on bacterial biology stems from the study in the planktonic state, an increasing interest is currently paid to bacterial behaviour as biofilm generators, as it is estimated that 65% of all bacterial infections are associated with bacterial biofilms. Infections of both upper and lower airways, bacterial endocarditis, chronic otitis media, urinary tract infections, periodontitis, ocular infections and chronic wound infections (including diabetic foot ulcer) are all associated with biofilm formation. The role of biofilm is also relevant in case of infections taking place on abiotic surfaces, as in the case of infections occurring on prostheses and several other medical devices. Here, we review current knowledge on biofilm formation and its impact on human infections, discussing recent means for its inhibition, with particular emphasis on an interesting anti-biofilm activity exerted by exopolysaccharides derived from marine strains of Bacillus licheniformis.}, } @article {pmid36189997, year = {2022}, author = {Xue, XF and Zhnag, MM and Sun, JF and Li, X and Wu, QM and Yin, Z and Yang, WH and Ni, B and Hu, LF and Zhou, DS and Lu, RF and Zhang, YQ}, title = {H-NS Represses Biofilm Formation and c-di-GMP Synthesis in Vibrio parahaemolyticus.}, journal = {Biomedical and environmental sciences : BES}, volume = {35}, number = {9}, pages = {821-829}, doi = {10.3967/bes2022.106}, pmid = {36189997}, issn = {2214-0190}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/analogs & derivatives ; Gene Expression Regulation, Bacterial ; Gentian Violet ; Histones/genetics/metabolism ; *Vibrio parahaemolyticus/genetics ; }, abstract = {OBJECTIVE: This study aimed to investigate the regulation of histone-like nucleoid structuring protein (H-NS) on biofilm formation and cyclic diguanylate (c-di-GMP) synthesis in Vibrio parahaemolyticus RIMD2210633.

METHODS: Regulatory mechanisms were analyzed by the combined utilization of crystal violet staining, quantification of c-di-GMP, quantitative real-time polymerase chain reaction, LacZ fusion, and electrophoretic-mobility shift assay.

RESULTS: The deletion of hns enhanced the biofilm formation and intracellular c-di-GMP levels in V. parahaemolyticus RIMD2210633. H-NS can bind the upstream promoter-proximal DNA regions of scrA, scrG, VP0117, VPA0198, VPA1176, VP0699, and VP2979 to repress their transcription. These genes encode a group of proteins with GGDEF and/or EAL domains associated with c-di-GMP metabolism.

CONCLUSION: One of the mechanisms by which H-NS represses the biofilm formation by V. parahaemolyticus RIMD2210633 may be via repression of the production of intracellular c-di-GMP.}, } @article {pmid36189827, year = {2022}, author = {Ribeiro, AA and Jiao, Y and Girnary, M and Alves, T and Chen, L and Farrell, A and Wu, D and Teles, F and Inohara, N and Swanson, KV and Marchesan, JT}, title = {Oral biofilm dysbiosis during experimental periodontitis.}, journal = {Molecular oral microbiology}, volume = {37}, number = {6}, pages = {256-265}, pmid = {36189827}, issn = {2041-1014}, support = {R01 AI153265/AI/NIAID NIH HHS/United States ; R01 DE023836/DE/NIDCR NIH HHS/United States ; T90 DE021986/DE/NIDCR NIH HHS/United States ; F32 DE026688/DE/NIDCR NIH HHS/United States ; P30 DK034987/DK/NIDDK NIH HHS/United States ; K01 DE027087/DE/NIDCR NIH HHS/United States ; P30 DK056350/DK/NIDDK NIH HHS/United States ; }, mesh = {Mice ; Animals ; Dysbiosis ; Mice, Inbred C57BL ; *Periodontitis/microbiology ; *Alveolar Bone Loss/microbiology ; Inflammation ; Biofilms ; Disease Models, Animal ; }, abstract = {OBJECTIVES: We have previously characterized the main osteoimmunological events that occur during ligature periodontitis. This study aims to determine the polymicrobial community shifts that occur during disease development.

METHODS: Periodontitis was induced in C57BL/6 mice using the ligature-induced periodontitis model. Healthy oral mucosa swabs and ligatures were collected every 3 days from 0 to 18 days post-ligature placement. Biofilm samples were evaluated by 16SrRNA gene sequencing (Illumina MiSeq) and QIIME. Time-course changes were determined by relative abundance, diversity, and rank analyses (PERMANOVA, Bonferroni-adjusted).

RESULTS: Microbial differences between health and periodontal inflammation were observed at all phylogenic levels. An evident microbial community shift occurred in 25 genera during the advancement of "gingivitis" (3-6 days) to periodontitis (9-18 days). From day 0 to 18, dramatic changes were identified in Streptococcus levels, with an overall decrease (54.04%-0.02%) as well an overall increase of Enterococcus and Lactobacillus (23.7%-73.1% and 10.1%-70.2%, respectively). Alpha-diversity decreased to its lowest at 3 days, followed by an increase in diversity as disease advancement. Beta-diversity increased after ligature placement, indicating that bone loss develops in response to a greater microbial variability (p = 0.001). Levels of facultative and strict anaerobic bacteria augmented over the course of disease progression, with a total of eight species significantly different during the 18-day period.

CONCLUSION: The data supports that murine gingival inflammation and alveolar bone loss develop in response to microbiome shifts. Bacterial diversity increased during progression to bone loss. These findings further support the utilization of the periodontitis ligature model for microbial shift analysis under different experimental conditions.}, } @article {pmid36189675, year = {2023}, author = {Ghaneialvar, H and Kayumov, A and Aboualigalehdari, E and Pakzad, I and Tanideh, N and Abbasi, N and Haddadi, MH}, title = {Docosahexaenoic acid-loaded chitosan/alginate membrane reduces biofilm formation by P. aeruginosa and promotes MSC-mediated burn wound healing.}, journal = {Journal of biomaterials applications}, volume = {37}, number = {8}, pages = {1458-1469}, doi = {10.1177/08853282221131130}, pmid = {36189675}, issn = {1530-8022}, mesh = {Humans ; *Chitosan/chemistry ; Pseudomonas aeruginosa ; Alginates/pharmacology ; Docosahexaenoic Acids/pharmacology ; Wound Healing ; Anti-Bacterial Agents/chemistry ; *Burns/drug therapy ; Biofilms ; }, abstract = {Aims: Chitosan, like docosahexaenoic acid (DHA) and mesenchymal stem cells (MSCs), is used in medicine as a wound healing accelerator. Thus, in this study, chitosan-alginate (CA) membranes containing DHA and MSCs were produced, and their antibacterial and antibiofilm activities against burn infections caused by Pseudomonas aeruginosa were investigated.Methods: Physicochemical properties were assessed by SEM, Fourier transform infrared (FTIR), and X-ray diffraction (XRD). Porosity, cytocompatibility, and antibacterial and antibiofilm activities were evaluated both in vitro and in vivo. The viability and apoptosis of MSCs were studied using flow cytometry. Wound healing effects were analyzed based on histopathological features, the wound contraction rate (WCR) ratio, and bacterial clearance.Results: The CA membranes showed antibiofilm activity both in vivo and in vitro, accompanied by reduced lasI and rhlI expressions and pyocyanin production. The membranes were highly porous and biocompatible and showed favorable physicochemical properties. Docosahexaenoic acid incorporation to CA membranes improved their antibacterial and antibiofilm activities, as well as MSCs' viability by reducing crystallinity and increasing porosity (p = .008). Treatment with CA-DHA-MSC accelerated burn wound healing (with complete healing being observed after 14 days, WCR = 85%) and augmented antibacterial and antibiofilm activities in vivo compared to CA-DHA and CA-MSC. The CA-DHA-MSC group delivered a significantly higher WCR and lower inflammation than the CA-MSC group (p = .0001).Conclusion: In combination with DHA-loaded CA membranes, MSCs reduced the healing time of burn wounds, offering a viable option for designing effective wound dressings.}, } @article {pmid36189355, year = {2022}, author = {Chiang, TT and Huang, TW and Sun, JR and Kuo, SC and Cheng, A and Liu, CP and Liu, YM and Yang, YS and Chen, TL and Lee, YT and Wang, YC}, title = {Biofilm formation is not an independent risk factor for mortality in patients with Acinetobacter baumannii bacteremia.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {964539}, pmid = {36189355}, issn = {2235-2988}, mesh = {*Acinetobacter Infections/drug therapy/epidemiology ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacteremia/drug therapy ; Biofilms ; Carbapenems/therapeutic use ; *Heart Failure ; Humans ; Microbial Sensitivity Tests ; Retrospective Studies ; Risk Factors ; }, abstract = {In the past decades, due to the high prevalence of the antibiotic-resistant isolates of Acinetobacter baumannii, it has emerged as one of the most troublesome pathogens threatening the global healthcare system. Furthermore, this pathogen has the ability to form biofilms, which is another effective mechanism by which it survives in the presence of antibiotics. However, the clinical impact of biofilm-forming A. baumannii isolates on patients with bacteremia is largely unknown. This retrospective study was conducted at five medical centers in Taiwan over a 9-year period. A total of 252 and 459 patients with bacteremia caused by biofilm- and non-biofilm-forming isolates of A. baumannii, respectively, were enrolled. The clinical demographics, antimicrobial susceptibility, biofilm-forming ability, and patient clinical outcomes were analyzed. The biofilm-forming ability of the isolates was assessed using a microtiter plate assay. Multivariate analysis revealed the higher APACHE II score, shock status, lack of appropriate antimicrobial therapy, and carbapenem resistance of the infected strain were independent risk factors of 28-day mortality in the patients with A. baumannii bacteremia. However, there was no significant difference between the 28-day survival and non-survival groups, in terms of the biofilm forming ability. Compared to the patients infected with non-biofilm-forming isolates, those infected with biofilm-forming isolates had a lower in-hospital mortality rate. Patients with either congestive heart failure, underlying hematological malignancy, or chemotherapy recipients were more likely to become infected with the biofilm-forming isolates. Multivariate analysis showed congestive heart failure was an independent risk factor of infection with biofilm-forming isolates, while those with arterial lines tended to be infected with non-biofilm-forming isolates. There were no significant differences in the sources of infection between the biofilm-forming and non-biofilm-forming isolate groups. Carbapenem susceptibility was also similar between these groups. In conclusion, the patients infected with the biofilm-forming isolates of the A. baumannii exhibited different clinical features than those infected with non-biofilm-forming isolates. The biofilm-forming ability of A. baumannii may also influence the antibiotic susceptibility of its isolates. However, it was not an independent risk factor for a 28-day mortality in the patients with bacteremia.}, } @article {pmid36188545, year = {2022}, author = {Pant, N and Miranda-Hernandez, S and Rush, C and Warner, J and Eisen, DP}, title = {Effect of savirin in the prevention of biofilm-related Staphylococcus aureus prosthetic joint infection.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {989417}, pmid = {36188545}, issn = {1663-9812}, abstract = {Background: Most of the arthroplasty surgery failure due to prosthetic joint infections (PJI) is caused by biofilm-associated Staphylococcus aureus. In a recent experimental study, savirin has been used to prevent and treat S. aureus skin infections in animal models. We explored the application of savirin in a PJI mouse model to determine its utility as an adjunct therapy to prevent PJI. Materials and methods: The in-vitro antibacterial and antibiofilm activity of savirin, with or without antibiotics (cefazolin, rifampicin, and vancomycin), against S. aureus were investigated using broth microdilution and crystal violet staining method, respectively. The effect of savirin treatment on the expression of the key biofilm-related genes (icaA, icaD, eno, fib, ebps, and agr) in S. aureus was studied using quantitative reverse transcriptase polymerase chain reaction (qRTPCR). The in-vivo efficacy of savirin alone and with cefazolin to prevent S. aureus PJI was determined using a clinically relevant PJI mouse model. Mice were randomized into five groups (n = 8/group): 1) infected K-wire savirin treated group, 2) infected K-wire cefazolin treated group, 3) infected K-wire savirin plus cefazolin treated group, 4) infected K-wire PBS treated group, 5) sterile K-wire group. Savirin was administered subcutaneously immediately post-surgery and intravenous cefazolin was given on day seven. Results: Savirin inhibited planktonic and biofilm in-vitro growth of S. aureus, showed enhanced inhibitory activity when combined with antibiotics, and down-regulated the expression of key S. aureus biofilm-related genes (icaA, icaD, eno, fib, ebps, and agr). Savirin significantly reduced bacterial counts on joint implants in comparison with the PBS treated control, while savirin plus cefazolin reduced bacterial counts on both implants and peri-prosthetic tissues. Conclusion: Savirin adjuvant therapy may prevent biofilm formation and S. aureus PJI. This study gives baseline data for using savirin for the prevention as well as treatment of S. aureus PJI in future animal studies.}, } @article {pmid36188210, year = {2022}, author = {Hamdoon, SM and AlSamak, S and Ahmed, MK and Gasgoos, S}, title = {Evaluation of biofilm formation on different clear orthodontic retainer materials.}, journal = {Journal of orthodontic science}, volume = {11}, number = {}, pages = {34}, pmid = {36188210}, issn = {2278-1897}, abstract = {AIM: To assess the chemical composition and oral biofilm formation on different types of commercially available clear orthodontic retainer materials (CORM).

MATERIALS AND METHODS: Four types of CORM commercially available were used (Clear advantage series I (CAS1), Clear advantage series II (CAS2), Endure (ES), and CENTRI FORM-clear rigid material (CFCRM)). Circular samples (12 mm diameter) of each CORM were prepared for (n = 40). Unstimulated saliva from twenty volunteers was collected. Fourier Transformation Infrared Spectroscopy (FTIR) was used for the evaluation of the chemical composition of CORM. For the quantitative assessment of oral biofilm formation, samples of each CORM were incubated for twenty-four hours, and crystal violet assay (CVA) was utilized. The degree of absorbance was measured using a spectrophotometer at 570 nm. For qualitative evaluation of oral formation, the samples of each CORM were incubated for 24 hours, and viable biofilm cells stained by acridine orange were examined under a fluorescent microscope.

RESULTS: FTIR findings showed that CAS2 was made of polypropylene and ES is made of polyvinyl chloride, while others were made of co-polyester. CVA results confirmed that CAS2 showed the lowest biofilm formation, which differs significantly compared to CAS1, CFCRM, and ES. No significant difference in biofilm formation was detected between CAS1, CFCRM, and ES. Viable biofilm cells staining by acridine orange showed that CAS2 demonstrated smaller microcolonies of viable biofilm cells compared with CAS1, CFCRM, and ES, which confirmed the result obtained by CVA.

CONCLUSIONS: CAS2 showed anti-microbial activities with a decrease the in vitro biofilm formation, which may be related to its chemical composition.}, } @article {pmid36187986, year = {2022}, author = {Wang, J and Peipoch, M and Guo, X and Kan, J}, title = {Convergence of biofilm successional trajectories initiated during contrasting seasons.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {991816}, pmid = {36187986}, issn = {1664-302X}, abstract = {Biofilm communities play a major role in explaining the temporal variation of biogeochemical conditions in freshwater ecosystems, and yet we know little about how these complex microbial communities change over time (aka succession), and from different initial conditions, in comparison to other stream communities. This has resulted in limited knowledge on how biofilm community structure and microbial colonization vary over relevant time scales to become mature biofilms capable of significant alteration of the freshwater environment in which they live. Here, we monitored successional trajectories of biofilm communities from summer and winter in a headwater stream and evaluated their structural state over time by DNA high-throughput sequencing. Significant differences in biofilm composition were observed when microbial colonization started in the summer vs. winter seasons, with higher percentage of algae (Bacillariophyta) and Bacteroidetes in winter-initiated samples but higher abundance of Proteobacteria (e.g., Rhizobiales, Rhodobacterales, Sphingomonadales, and Burkholderiales), Actinobacteria, and Chloroflexi in summer-initiated samples. Interestingly, results showed that despite seasonal effects on early biofilm succession, biofilm community structures converged after 70 days, suggesting the existence of a stable, mature community in the stream that is independent of the environmental conditions during biofilm colonization. Overall, our results show that algae are important in the early development of biofilm communities during winter, while heterotrophic bacteria play a more critical role during summer colonization and development of biofilms.}, } @article {pmid36187911, year = {2022}, author = {Nasrollahian, S and Halaji, M and Hosseini, A and Teimourian, M and Armaki, MT and Rajabnia, M and Gholinia, H and Pournajaf, A}, title = {Genetic Diversity, Carbapenem Resistance Genes, and Biofilm Formation in UPEC Isolated from Patients with Catheter-Associated Urinary Tract Infection in North of Iran.}, journal = {International journal of clinical practice}, volume = {2022}, number = {}, pages = {9520362}, pmid = {36187911}, issn = {1742-1241}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Carbapenems/pharmacology ; Catheters ; Cross-Sectional Studies ; Edetic Acid ; Genetic Variation ; Humans ; Iran/epidemiology ; Nalidixic Acid ; Trimethoprim, Sulfamethoxazole Drug Combination ; *Urinary Tract Infections ; beta-Lactamases/genetics ; }, abstract = {BACKGROUND: Infections due to carbapenem-resistant Enterobacteriaceae (CRE) are associated in patients with urinary catheters alarming rate of emergency status. The aim of this study is to investigate the molecular causes of carbapenem resistance among UPEC as well as antimicrobial resistance trends. Additionally, the potential of isolates to produce biofilms, in addition to their clonal and genetic diversity, was investigated. Material and Methods. A cross-sectional study was accomplished on a collection of 76 non-duplicate UPEC isolates obtained from CAUTIs from May 2021 to September 2021. The modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM) test was performed for the detection of carbapenemase and metallo-beta-lactamase activity. Also, the presence of carbapenemase genes was determined using PCR assays. In 96-well microtiter plates, biofilm development was evaluated. ERIC-PCR was used to investigate the clonal and genetic variety of isolates.

RESULTS: A total of 76 confirmed UPEC isolates were obtained from patients mentioned to teaching hospitals in Babol, Iran. The results of antibiotic susceptibility testing revealed a high rate of antibiotic resistance against nalidixic acid (81.6%) and trimethoprim-sulfamethoxazole (80.3%). Among UPEC isolates, 63.2% and 13.2% of UPEC isolates were positive for MBL production. The frequencies of the studied genes are in order of bla NDM (14.5%), bla OXA-23 (2.6%), and bla OXA-48 (2.6%). Forty-two isolates (55.3%) were positive for biofilm formation. ERIC-PCR revealed that UPEC isolates could be categorized into nine clusters A-I and five isolates were categorized as a singleton.

CONCLUSION: The high prevalence of MDR and carbapenemase-producing isolates among the UPEC strain in this investigation is concerning. Moreover, the bla NDM was the most frequent cause of producing metallo-beta-lactamase and carbapenemase. Also, analysis revealed a partial genetic similarity among the studied isolates, indicating that the same UPEC clones may have spread to other hospital units.}, } @article {pmid36185513, year = {2022}, author = {Santajit, S and Kong-Ngoen, T and Tunyong, W and Pumirat, P and Ampawong, S and Sookrung, N and Indrawattana, N}, title = {Occurrence, antimicrobial resistance, virulence, and biofilm formation capacity of Vibrio spp. and Aeromonas spp. isolated from raw seafood marketed in Bangkok, Thailand.}, journal = {Veterinary world}, volume = {15}, number = {7}, pages = {1887-1895}, pmid = {36185513}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Bacteria of the genera Vibrio and Aeromonas cause seafood-borne zoonoses, which may have a significant impact on food safety, economy, and public health worldwide. The presence of drug-resistant and biofilm-forming phenotypes in the food chain increases the risk for consumers. This study aimed to investigate the characteristics, virulence, biofilm production, and dissemination of antimicrobial-resistant pathogens isolated from seafood markets in Bangkok, Thailand.

MATERIALS AND METHODS: A total of 120 retail seafood samples were collected from 10 local markets in Bangkok and peripheral areas. All samples were cultured and the Vibrio and Aeromonas genera were isolated using selective agar and biochemical tests based on standard protocols (ISO 21872-1: 2017). The antibiotic susceptibility test was conducted using the disk diffusion method. The presence of hemolysis and protease production was also investigated. Polymerase chain reaction (PCR) was used to determine the presence of the hlyA gene. Furthermore, biofilm formation was characterized by microtiter plate assay and scanning electron microscopy.

RESULTS: The bacterial identification test revealed that 35/57 (61.4%) belonged to the Vibrio genus and 22/57 (38.6%) to the Aeromonas genus. The Kirby-Bauer test demonstrated that 61.4% of the isolates were resistant to at least one antibiotic and 45.61% had a high multiple antibiotic resistance index (≥0.2). PCR analysis indicated that 75.44% of the bacteria harbored the hlyA gene. Among them, 63.16% exhibited the hemolysis phenotype and 8.77% showed protease activity. The biofilm formation assay demonstrated that approximately 56.14% of all the isolates had the potential to produce biofilms. The moderate biofilm production was the predominant phenotype.

CONCLUSION: The results of this study provide evidence of the multiple drug resistance phenotype and biofilm formation capacity of Vibrio and Aeromonas species contaminating raw seafood. Effective control measures and active surveillance of foodborne zoonoses are crucial for food safety and to decrease the occurrence of diseases associated with seafood consumption.}, } @article {pmid36184018, year = {2023}, author = {Fortes, BN and Scheunemann, G and de Azevedo Melo, AS and Ishida, K}, title = {Caspofungin alone or combined with polymyxin B are effective against mixed biofilm of Aspergillus fumigatus and carbapenem-resistant Pseudomonas aeruginosa.}, journal = {Research in microbiology}, volume = {174}, number = {1-2}, pages = {103993}, doi = {10.1016/j.resmic.2022.103993}, pmid = {36184018}, issn = {1769-7123}, mesh = {Caspofungin/pharmacology/metabolism ; *Polymyxin B/pharmacology/metabolism ; Aspergillus fumigatus ; Pseudomonas aeruginosa ; *Anti-Infective Agents/pharmacology ; Biofilms ; Carbapenems/pharmacology/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Aspergillus fumigatus and Pseudomonas aeruginosa biofilms are associated to the recalcitrant and persistent infections due to resistance to antimicrobials. Here, we evaluated the effect of antimicrobials on single and mixed biofilms of A. fumigatus and P. aeruginosa (carbapenem-resistant and susceptible strains) determining total biomass by crystal violet, cell viability by colony forming unit count, and microscopy. Polymyxin B (PMB) had the best action on P. aeruginosa biofilms inhibiting the biomass (2-4 μg/mL) and it was efficient reducing the viable bacterial cells. Amphotericin B (AMB) and caspofungin (CAS) were the best antifungal at inhibiting A. fumigatus biofilms and reducing fungal viability at concentration ≥1 and ≥ 16 μg/mL, respectively. In addition, CAS was able to significantly reduce P. aeruginosa viability in mixed biofilms. CAS combined with PMB also significantly reduced the mixed biofilm biomass and fungal and bacterial viability mainly against carbapenem-resistant bacterium. The light and fluorescence microscopy showed alterations on hyphae morphology and confirmed the increase of fungal and bacterial death cells after combined therapy of mixed biofilms. Taken together, our work showed that CAS alone and its combination with PMB showed better potential in reducing mixed biofilm biomass and fungal and bacterial viability, even for the carbapenem-resistant P. aeruginosa strain.}, } @article {pmid36182012, year = {2022}, author = {Sapmaz, T and Manafi, R and Mahboubi, A and Lorick, D and Koseoglu-Imer, DY and Taherzadeh, MJ}, title = {Potential of food waste-derived volatile fatty acids as alternative carbon source for denitrifying moving bed biofilm reactors.}, journal = {Bioresource technology}, volume = {364}, number = {}, pages = {128046}, doi = {10.1016/j.biortech.2022.128046}, pmid = {36182012}, issn = {1873-2976}, abstract = {Fossil-based materials such as methanol are frequently used in the denitrification process of advanced biological wastewater treatment as external carbon source. Volatile fatty acids (VFAs) produced by anaerobic digestion of food waste, are sustainable compounds with the potential to act as carbon sources for denitrification, reducing carbon footprint and material costs. In this study, the effectiveness of food waste-derived VFAs (AD-VFA) was investigated in the post-denitrification process in comparison with synthetic VFA and methanol as carbon sources. Acetic acid had the highest rate of disappearance among single tested VFAs with a denitrification rate of 0.44 g NOx-N removed/m[2]/day, indicating a preferential utilization pattern. While AD-VFA had a denitrification rate of 0.61 mg NOx-N removed/m[2]/day, sVFA had a rate of 0.57 mg NOx-N removed/m[2]/day, indicating that impurities in AD-VFA did not play substantial role in denitrification. AD-VFA proved to be promising carbon source alternative for denitrification in wastewater treatment plants.}, } @article {pmid36181921, year = {2022}, author = {Sivaraj, D and Arumugam, G and Kalimuthu, V and Rajendran, R}, title = {Enhanced anti-biofilm and biocompatibility of Zn and Mg substituted β-tricalcium phosphate/functionalized multiwalled carbon nanotube composites towards A. baumannii and Methicillin-Resistant Staphylococcus aureus, and MG-63 cells.}, journal = {International journal of pharmaceutics}, volume = {627}, number = {}, pages = {122248}, doi = {10.1016/j.ijpharm.2022.122248}, pmid = {36181921}, issn = {1873-3476}, mesh = {*Nanotubes, Carbon/chemistry ; *Methicillin-Resistant Staphylococcus aureus ; *Nanocomposites/chemistry ; Biofilms ; Anti-Bacterial Agents/pharmacology/chemistry ; Zinc ; }, abstract = {In this work, Zn and Mg substituted β-tricalcium phosphate/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposites were prepared by the co-precipitation method. The structural, vibrational, morphological and biological properties of the prepared nanocomposites were studied. The structural study revealed that the increase of Zn concentration shifts the β-tricalcium phosphate planes towards higher angle. Morphological analysis confirmed the formation of hexagonal-shaped particles after substitution of Zn. The particle size of the nanoparticles decreased with the increase of Zn concentration. XPS analysis clearly showed the presence of Zn, Mg, P, Ca, O and C. The Zn (5%) rich nanocomposites have better antibiofilm activity compared to 2% of zinc substituted composite. Also, it has been proven that the prepared nanocomposites have the ability to enhance the bioactivity of commercial antibiotics by means of a decrease in drug resistance. Finally, this study acted as a pioneer to improve drug efficiency and reduced the biofilm formation of certain medically important bacteria. The in-vitro cell viability and anti-biofilm results of zinc (5%) rich nanocomposite confirmed that prepared nanocomposite has biocompatible and enhanced anti-biofilm property, which will be beneficial candidate for biomedical applications.}, } @article {pmid36181858, year = {2022}, author = {Lan, M and Kang, Y and Wang, J and Li, M and Zhang, P and Zhang, P and Li, B}, title = {In-situ enrichment and application of heterotrophic nitrification-aerobic denitrification bacteria in membrane aerated biofilm reactor.}, journal = {Chemosphere}, volume = {309}, number = {Pt 1}, pages = {136643}, doi = {10.1016/j.chemosphere.2022.136643}, pmid = {36181858}, issn = {1879-1298}, mesh = {*Nitrification ; *Denitrification ; Heterotrophic Processes ; Sewage ; Tryptophan/metabolism ; Bioreactors ; Biofilms ; Nitrogen/metabolism ; Bacteria/metabolism ; Wastewater ; }, abstract = {In order to reduce the resource and energy consumption of traditional biological nitrogen removal (BNR) process, heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria was in situ enriched in membrane aerated biofilm reactor (MABR) by inoculating conventional activated sludge. Contaminants removal performance, EPS composition and microbial community were explored. The results indicated that the average removal efficiency of COD and TN under optimal condition reached 84.13% and 91.54%, respectively, which demonstrated that the reactor possessed excellent contaminants removal capacity. EPS analysis suggested that abundant protein especially tryptophan protein-like substance played a vital role in maintaining the microbial stability of biofilms. Multiple HN-AD genera, mainly Paracoccus, were detected with the highest relative abundance of 54.70%, which confirmed the successful enrichment of the HN-AD bacteria. Conventional nitrifiers and denitrifiers also thrived in biofilm, which demonstrated the synergistic nitrogen removal of multiple microorganisms. This study provided important insights into application of HN-AD bacteria and synergistic nitrogen removal in BNR system.}, } @article {pmid36178825, year = {2022}, author = {Liu, S and Chen, H and Zhang, X and Zhang, B and Zhu, H and Chen, H and Wen, B and Chen, L}, title = {Degradation of tetracycline wastewater by suspended biochar as carriers in moving bed biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {6}, pages = {1578-1589}, doi = {10.2166/wst.2022.285}, pmid = {36178825}, issn = {0273-1223}, mesh = {Anti-Bacterial Agents ; Biofilms ; Bioreactors ; Charcoal ; Denitrification ; *Heterocyclic Compounds ; Nitrification ; Nitrogen/chemistry ; Polyethylene ; Tetracycline ; Waste Disposal, Fluid/methods ; *Wastewater ; }, abstract = {To improve the removal efficiency of antibiotics in moving bed biofilm reactor, suspended biochar block was prepared by the one-pot process and was used as carriers to construct a reaction device to study the treatment effect of antibiotic wastewater. The characteristics of the hanging biofilm in wastewater were investigated. And the mechanism of biochar as a biological carrier has been studied. The results showed that in the 45-day experiment, the maximum number of biofilms for suspended biochar carriers was twice 3.4 times that of the high-density polyethylene carriers. When 10 mg/L tetracycline was added to the reactor, the removal efficiency of the tetracycline removal rate was 71.85% and the chemical oxygen demand (COD), total nitrogen (TN), and NH4[+]-N removal efficiency reached to 89.95, 61.91 and 85.47% respectively. Suspension biochar carriers can reduce fluctuations in redox potentials, thereby improving the cellular efficiency of microorganisms. Meanwhile, it inhibits the production of soluble microbial products and extracellular polymers, reduces toxic effects, and enhances the adhesion between microorganisms and carriers. The microbial communities of the two carriers were investigated by high-throughput sequencing techniques. Suspended biochar significantly increased the relative abundance of Hydrogenophaga and Comamonas, and improved the ability of nitrification and denitrification. Comamonas could be responsible for tetracycline degradation.}, } @article {pmid36178811, year = {2022}, author = {Chang, W and Zhu, X and Sun, J and Pang, Y and Zhang, S}, title = {Effects of lead pollution on bacterial communities in biofilm attached to submerged plants.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {86}, number = {6}, pages = {1358-1372}, doi = {10.2166/wst.2022.279}, pmid = {36178811}, issn = {0273-1223}, mesh = {Antioxidants/metabolism/pharmacology ; Biofilms ; Chlorophyll A/metabolism/pharmacology ; *Cyanobacteria ; *Hydrocharitaceae/metabolism ; Hydrogen Peroxide ; Lead/metabolism/toxicity ; Malondialdehyde/metabolism/pharmacology ; *Metals, Heavy/metabolism ; Nitrogen/metabolism ; Proteobacteria ; Sulfur/metabolism ; }, abstract = {Submerged plants and biofilms have significant advantages in hydro-ecology rehabilitation, but their tolerance and physiological responses to heavy metal stress have thus far been under-investigated. This study investigated the influence of lead on physiological and biochemical responses, as well as variation in bacterial communities and functional characteristics of submerged plant biofilms. The results showed that chlorophyll a content of two submerged plants decreased with increased lead concentration. The concentration of malondialdehyde of both submerged plants was higher under high lead concentrations than under low lead concentrations, and the concentrations of malondialdehyde and hydrogen peroxide in Vallisneria natans were more stable. The antioxidant enzyme systems of the two plants played protective roles against lead stress. High lead concentration can inhibit the bacterial community and lead to decreased diversity. The most abundant bacterial phyla were Proteobacteria (40.9%), Cyanobacteria (21.5%), and Bacteroidetes (14.3%). Proteobacteria abundance decreased with increased lead concentration, while Cyanobacteria abundance increased. The lead concentration in plants (19.7%, P < 0.01) and the lead concentration in aquatic environment (17.7%, P < 0.01) were significantly correlated with variation in bacterial communities. High lead concentration inhibits the activity of these bacteria related to the conversion of nitrogen and sulfur.}, } @article {pmid36178801, year = {2022}, author = {Zhang, C and Li, Z and Pan, Q and Fan, L and Pan, T and Zhu, F and Pan, Q and Shan, L and Zhao, L}, title = {Berberine at sub-inhibitory concentration inhibits biofilm dispersal in Staphylococcus aureus.}, journal = {Microbiology (Reading, England)}, volume = {168}, number = {9}, pages = {}, doi = {10.1099/mic.0.001243}, pmid = {36178801}, issn = {1465-2080}, mesh = {Anti-Bacterial Agents/pharmacology ; *Berberine/pharmacology ; Biofilms ; Humans ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus ; }, abstract = {Staphylococcus aureus is a major human pathogen, which has multiple drug resistance and can cause serious infections. Recent studies have shown that berberine has antibacterial activity and it can affect biofilm formation of S. aureus. However, the berberine effect on the biofilm of S. aureus is controversial. In this study, we investigate the effect of berberine on the biofilm development in S. aureus NCTC8325 and explore the possible mechanism. Susceptibility test shows that berberine inhibits growth of methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA) and vancomycin-intermediate S. aureus (VISA) at different concentrations. S. aureus NCTC8325 is chosen as a model strain to explore further the berberine effect. The MIC of berberine for S. aureus NCTC8325 is 256 µg ml[-1]. Berberine below 32 µg ml[-1] inhibits the dispersal of biofilm and stimulates clumping of cells of NCTC8325 in a concentration-dependent manner, while not showing obvious inhibition on the bacterial growth. The transcription of the key negative regulator of biofilm dispersal AgrA is decreased and an agrA mutant forms biofilm reaching to a similar level of biomass to WT in the presence of berberine at 32 µg ml[-1]. Transcription of some genes involving synthesis of biofilm structure components, including polysaccharide intracellular adhesin (PIA), proteins and eDNA were also up-regulated, especially icaA for PIA synthesis. And consistently, PIA content was increased in cells exposed to berberine at 32 µg ml[-1]. This study reveals the dependence of berberine inhibition of biofilm dispersal on the Agr system, which is the first report exploring the molecule mechanism of the berberine effect on the biofilm of S. aureus.}, } @article {pmid36178765, year = {2022}, author = {Bekő, K and Nagy, EZ and Grózner, D and Kreizinger, Z and Gyuranecz, M}, title = {Biofilm formation and its impact on environmental survival and antibiotic resistance of Mycoplasma anserisalpingitidis strains.}, journal = {Acta veterinaria Hungarica}, volume = {}, number = {}, pages = {}, doi = {10.1556/004.2022.00029}, pmid = {36178765}, issn = {0236-6290}, abstract = {Several Mycoplasma species can form biofilm, facilitating their survival in the environment, and shielding them from therapeutic agents. The aim of this study was to examine the biofilm-forming ability and its potential effects on environmental survival and antibiotic resistance in Mycoplasma anserisalpingitidis, the clinically and economically most important waterfowl Mycoplasma species. The biofilm-forming ability of 32 M. anserisalpingitidis strains was examined by crystal violet assay. Biofilms and planktonic cultures of the selected strains were exposed to a temperature of 50 °C (20 and 30 min), to desiccation at room temperature (16 and 24 h), or to various concentrations of eight different antibiotics. Crystal violet staining revealed great diversity in the biofilm-forming ability of the 32 tested M. anserisalpingitidis strains, with positive staining in more than half of them. Biofilms were found to be more resistant to heat and desiccation than planktonic cultures, while no correlation was shown between biofilm formation and antibiotic susceptibility. Our results indicate that M. anserisalpingitidis biofilms may contribute to the persistence of the organisms in the environment, which should be taken into account for proper management. Antibiotic susceptibility was not affected by biofilm formation; however, it is important to note that correlations were examined only in vitro.}, } @article {pmid36175161, year = {2022}, author = {Gao, J and Sadiq, FA and Zheng, Y and Zhao, J and He, G and Sang, Y}, title = {Biofilm-based delivery approaches and specific enrichment strategies of probiotics in the human gut.}, journal = {Gut microbes}, volume = {14}, number = {1}, pages = {2126274}, pmid = {36175161}, issn = {1949-0984}, mesh = {Biofilms ; *Gastrointestinal Microbiome ; Gastrointestinal Transit ; Humans ; Prebiotics ; *Probiotics ; }, abstract = {The use of probiotics has been one of the effective strategies to restructure perturbed human gut microbiota following a disease or metabolic disorder. One of the biggest challenges associated with the use of probiotic-based gut modulation strategies is to keep the probiotic cells viable and stable during the gastrointestinal transit. Biofilm-based probiotics delivery approaches have emerged as fascinating modes of probiotic delivery in which probiotics show significantly greater tolerance and biotherapeutic potential, and interestingly probiotic biofilms can be developed on food-grade surfaces too, which is ideal for the growth and proliferation of bacterial cells for incorporation into food matrices. In addition, biofilms can be further encapsulated with food-grade materials or with bacterial self-produced biofilms. This review presents a newly emerging and unprecedently discussed techniques for the safe delivery of probiotics based on biofilms and further discusses newly emerging prebiotic materials which target specific gut microbiota groups for growth and proliferation.}, } @article {pmid36174687, year = {2023}, author = {Flores-Alsina, X and Uri-Carreno, N and Nielsen, PH and Gernaey, KV}, title = {Modelling the impacts of operational conditions on the performance of a full-scale membrane aerated biofilm reactor.}, journal = {The Science of the total environment}, volume = {856}, number = {Pt 1}, pages = {158980}, doi = {10.1016/j.scitotenv.2022.158980}, pmid = {36174687}, issn = {1879-1026}, mesh = {*Bioreactors/microbiology ; *Biofilms ; Wastewater/chemistry ; Nitrification ; Nitrogen ; Sulfates ; Waste Disposal, Fluid/methods ; }, abstract = {Membrane Aerated Biofilm Reactors (MABR) are gaining more and more acceptance in the plethora of wastewater process intensification technologies. Mathematical modelling has contributed to show their feasibility in terms of reduced energy consumption and footprint. Nevertheless, most simulation studies published until now are still focused on analyzing MABR as single units and not fully integrated within the flow diagram of the water treatment plant (WWTP). In this paper, the prediction capabilities of an integrated modelling approach is tested using full-scale data from Ejby Mølle WWTP+MABR site (Odense, Denmark). Mass balances, data reconciliation methods, process simulation and the different evaluation criteria were used to adjust influent, effluent and process indicators. Results show 10 % mismatch between flow, COD, N and P predictions and measurements in different plant locations. Using the adopted hydraulic retention time (HRT), nitrogen load (NL), membrane surface area (MA) and oxygen transfer rate (OTR), it was possible to predict nitrification rates (NR) within the interquartile range. This has been done under two different MABR operational conditions: with (#S2) and without (#S1) external aeration (EA) in the bulk liquid. The model provides additional process insights about biofilm structure, substrate gradients, weak acid base chemistry and precipitation potential. More specifically, simulations suggest the potential undesirable effects of sulfate (SRB) and iron reducing bacteria (IRB) on both microbial activity and composition of the biofilm. The latter may have a strong impact on ammonium (NHx), sulfate (SOx) and ferrous ion (Fe[+2]) conversion processes. The change of operational strategy in the scenario analysis highlights that the denitrifying activity of phosphorus accumulating organisms (PAOs) can enhance nutrient removal in MABR tanks. In addition, it was possible to assess the chance of success (in terms of energetic cost of nitrogen removal) of adding several MABR units in one tank of the WWTP under study before full-scale implementation.}, } @article {pmid36174231, year = {2022}, author = {Pütz, E and Gazanis, A and Keltsch, NG and Jegel, O and Pfitzner, F and Heermann, R and Ternes, TA and Tremel, W}, title = {Communication Breakdown: Into the Molecular Mechanism of Biofilm Inhibition by CeO2 Nanocrystal Enzyme Mimics and How It Can Be Exploited.}, journal = {ACS nano}, volume = {16}, number = {10}, pages = {16091-16108}, doi = {10.1021/acsnano.2c04377}, pmid = {36174231}, issn = {1936-086X}, mesh = {*Acyl-Butyrolactones/chemistry/metabolism/pharmacology ; Hydrogen Peroxide/pharmacology ; Bromides ; Biofilms ; Quorum Sensing ; Pseudomonas aeruginosa ; Bacteria/metabolism ; Anti-Bacterial Agents/pharmacology ; *Nanoparticles ; }, abstract = {Bacterial biofilm formation is a huge problem in industry and medicine. Therefore, the discovery of anti-biofilm agents may hold great promise. Biofilm formation is usually a consequence of bacterial cell-cell communication, a process called quorum sensing (QS). CeO2 nanocrystals (NCs) have been established as haloperoxidase (HPO) mimics and ecologically beneficial biofilm inhibitors. They were suggested to interfere with QS, a mechanism termed quorum quenching (QQ), but their molecular mechanism remained elusive. We show that CeO2 NCs are effective QQ agents, inactivating QS signals by bromination. Catalytic bromination of 3-oxo-C12-AHL a QS signaling compound used by Pseudomonas aeruginosa, was detected in the presence of CeO2 NCs, bromide ions, and hydrogen peroxide. Brominated acyl-homoserine lactones (AHLs) no longer act as QS signals but were not detected in the bacterial cultures. Externally added brominated AHLs also disappeared in P. aeruginosa cultures within minutes of their addition, indicating that they are rapidly degraded by the bacteria. Moreover, we detected the catalytic bromination of 2-heptyl-1-hydroxyquinolin-4(1H)-one (HQNO), a multifunctional non-AHL QS signal from P. aeruginosa with antibacterial and algicidal properties controlling the expression of many virulence genes. Brominated HQNO was not degraded by the bacteria in vivo. The repression of the Pseudomonas quinolone signal (PQS) production and biofilm formation in P. aeruginosa through the catalytic formation of Br-HQNO on surfaces with coatings containing CeO2 enzyme mimics validates the non-toxic strategy for the development of anti-infectives.}, } @article {pmid36172502, year = {2022}, author = {Arboleda-Baena, C and Pareja, CB and Pla, I and Logares, R and De la Iglesia, R and Navarrete, SA}, title = {Hidden interactions in the intertidal rocky shore: variation in pedal mucus microbiota among marine grazers that feed on epilithic biofilm communities.}, journal = {PeerJ}, volume = {10}, number = {}, pages = {e13642}, pmid = {36172502}, issn = {2167-8359}, mesh = {Animals ; Mollusca ; *Gastropoda ; *Microbiota/genetics ; *Polyplacophora ; *Gammaproteobacteria ; Biofilms ; Mucus ; }, abstract = {In marine ecosystems, most invertebrates possess diverse microbiomes on their external surfaces, such as those found in the pedal mucus of grazing gastropods and chitons that aids displacement on different surfaces. The microbes are then transported around and placed in contact with free-living microbial communities of micro and other macro-organisms, potentially exchanging species and homogenizing microbial composition and structure among grazer hosts. Here, we characterize the microbiota of the pedal mucus of five distantly related mollusk grazers, quantify differences in microbial community structure, mucus protein and carbohydrate content, and, through a simple laboratory experiment, assess their effects on integrated measures of biofilm abundance. Over 665 Amplicon Sequence Variants (ASVs) were found across grazers, with significant differences in abundance and composition among grazer species and epilithic biofilms. The pulmonate limpet Siphonaria lessonii and the periwinkle Echinolittorina peruviana shared similar microbiota. The microbiota of the chiton Chiton granosus, keyhole limpet Fissurella crassa, and scurrinid limpet Scurria araucana differed markedly from one another, and form those of the pulmonate limpet and periwinkle. Flavobacteriaceae (Bacteroidia) and Colwelliaceae (Gammaproteobacteria) were the most common among microbial taxa. Microbial strict specialists were found in only one grazer species. The pedal mucus pH was similar among grazers, but carbohydrate and protein concentrations differed significantly. Yet, differences in mucus composition were not reflected in microbial community structure. Only the pedal mucus of F. crassa and S. lessonii negatively affected the abundance of photosynthetic microorganisms in the biofilm, demonstrating the specificity of the pedal mucus effects on biofilm communities. Thus, the pedal mucus microbiota are distinct among grazer hosts and can affect and interact non-trophically with the epilithic biofilms on which grazers feed, potentially leading to microbial community coalescence mediated by grazer movement. Further studies are needed to unravel the myriad of non-trophic interactions and their reciprocal impacts between macro- and microbial communities.}, } @article {pmid36170978, year = {2022}, author = {Bhatt, P and Bhatt, K and Huang, Y and Li, J and Wu, S and Chen, S}, title = {Biofilm formation in xenobiotic-degrading microorganisms.}, journal = {Critical reviews in biotechnology}, volume = {}, number = {}, pages = {1-21}, doi = {10.1080/07388551.2022.2106417}, pmid = {36170978}, issn = {1549-7801}, abstract = {The increased presence of xenobiotics affects living organisms and the environment at large on a global scale. Microbial degradation is effective for the removal of xenobiotics from the ecosystem. In natural habitats, biofilms are formed by single or multiple populations attached to biotic/abiotic surfaces and interfaces. The attachment of microbial cells to these surfaces is possible via the matrix of extracellular polymeric substances (EPSs). However, the molecular machinery underlying the development of biofilms differs depending on the microbial species. Biofilms act as biocatalysts and degrade xenobiotic compounds, thereby removing them from the environment. Quorum sensing (QS) helps with biofilm formation and is linked to the development of biofilms in natural contaminated sites. To date, scant information is available about the biofilm-mediated degradation of toxic chemicals from the environment. Therefore, we review novel insights into the impact of microbial biofilms in xenobiotic contamination remediation, the regulation of biofilms in contaminated sites, and the implications for large-scale xenobiotic compound treatment.}, } @article {pmid36170918, year = {2023}, author = {Perveen, S and Pablos, C and Reynolds, K and Stanley, S and Marugán, J}, title = {Growth and prevalence of antibiotic-resistant bacteria in microplastic biofilm from wastewater treatment plant effluents.}, journal = {The Science of the total environment}, volume = {856}, number = {Pt 2}, pages = {159024}, doi = {10.1016/j.scitotenv.2022.159024}, pmid = {36170918}, issn = {1879-1026}, mesh = {*Microplastics ; Plastics ; Genes, Bacterial ; Wastewater/microbiology ; Prevalence ; Bacteria ; Angiotensin Receptor Antagonists ; Anti-Bacterial Agents/pharmacology ; Angiotensin-Converting Enzyme Inhibitors ; Biofilms ; *Water Purification ; Water ; }, abstract = {It is accepted that Microplastic (MP) biofilms accumulates antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in water. ARB/ARGs and MPs are emerging pollutants of concern due to various associated health risks. The objective of this study was to 1) investigate the ARB community in a pilot-scale wastewater treatment plant (WWTP) effluent, 2) to study and visualize the ARB/ARGs in MP biofilm grown in WWTP effluent and tap water, and 3) to analyze microplastic adherent ARB/ARGs in the biofilm and planktonic ARB/ARGs in the filtrate under controlled conditions. Results indicated the dominance of Pseudomonas, Aeromonas, and Bacillus among isolated ARB in WWTP effluent. Representative resistance strains were incubated in 300 mL water containing commercial polystyrene beads of 300550 μm diameter (MP) in a series of batch experiments. Microbiological, molecular, and microscopic analyses were performed by enumeration, 16srRNA, real-time polymerase chain reaction (qPCR), and Field Emission-Scanning Electron Microscopy (FEG-SEM) techniques. The analyzed viable ARB indicated an increasing trend in MP biofilms between days 3 and 5. It further decreased on days 7 and 9. The prevalence of ARB in the filtrate and MP biofilm varied as a function of time and TOC level, while no significant impacts were observed for minor temperature variation, low antibiotic pressure, and increased MP mass with few exceptions. Relative abundance of ARGs (vanA, sul1) and integron integrase gene (intl1) in MP biofilm were significantly different across different TOC levels, time, and antibiotic pressure. ARGs and intl1 were detected in the MP biofilm in tap water and WWTP effluent on day 30.}, } @article {pmid36170195, year = {2022}, author = {Schüroff, PA and Andrade, FB and Pelayo, JS}, title = {Virulence markers, adhesion and biofilm formation of Escherichia coli strains isolated from drinking water supplies of north Paraná State, Brazil.}, journal = {Journal of water and health}, volume = {20}, number = {9}, pages = {1416-1424}, doi = {10.2166/wh.2022.128}, pmid = {36170195}, issn = {1477-8920}, mesh = {Biofilms ; Brazil/epidemiology ; Diarrhea/epidemiology ; *Drinking Water ; *Enteropathogenic Escherichia coli/genetics ; *Escherichia coli Infections/epidemiology ; *Escherichia coli Proteins/genetics ; Humans ; Shiga Toxins ; Virulence ; }, abstract = {Waterborne diseases are a major public health problem responsible for a high number of deaths worldwide, of which Escherichia coli is a major agent of contamination. This study investigates the occurrence of different diarrheagenic E. coli (DEC) pathotypes and its relationship with adherence patterns and biofilm formation. Between 2012 and 2014, a total of 1,780 drinking water samples were collected from different rural communities and urban water systems of north Paraná State. A total of 14% were positive for E. coli and 250 non-duplicate E. coli isolates were obtained. Between the E. coli isolates, 28 (11.2%) harbored DEC-associated genes, 10.7% being classified as Shiga toxin-producing E. coli (STEC), 64.3% enteroaggregative E. coli (EAEC) and 25% atypical enteropathogenic E. coli (aEPEC). The aggregative adherence (AA) was the predominant adherence pattern (84%), significantly associated with biofilm formation (p < 0.0001). On the other hand, the AA pattern and biofilm formation were not significantly associated to DEC pathotypes (p > 0.05). Therefore, we proposed that the AA pattern and biofilm formation in E. coli isolated from drinking water supplies could be associated with adherence and colonization of abiotic surfaces, such as pipes, leading to persistence and resistance to treatment or disinfection.}, } @article {pmid36170000, year = {2023}, author = {Assery, N and Alomeir, N and Zeng, Y and Xiao, J and Tsigarida, A}, title = {The effect of Er:YAG laser treatment on biofilm formation on titanium and zirconia disc surfaces.}, journal = {Journal of periodontology}, volume = {94}, number = {3}, pages = {344-353}, doi = {10.1002/JPER.22-0243}, pmid = {36170000}, issn = {1943-3670}, mesh = {Humans ; *Lasers, Solid-State/therapeutic use ; *Dental Implants/microbiology ; Titanium ; Biofilms ; Surface Properties ; Microscopy, Electron, Scanning ; }, abstract = {BACKGROUND: Lasers represent a promising method for implant decontamination, but evidence on implant surface changes and subsequent biofilm formation is limited. This study aimed to assess the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment on zirconia and titanium discs, and the differences in biofilm formation as a result of surface alterations.

METHODS: A two-stage (in vitro and in vivo) experiment utilizing Er:YAG laser on titanium and zirconia discs was performed. In vitro, surface alterations, roughness, and elemental-material weight differences following laser treatment were assessed using scanning electron microscopy and atomic force microscopy. In vivo, four participants wore custom-made intra-oral stents, embedded with laser-treated and untreated titanium and zirconia discs overnight. Biofilm-coated discs were stained using nucleic acid fluorescence dye and visualized using multiphoton confocal laser scanning microscopy. Biofilm 3D structure, biomass, thickness, and live-to-dead bacteria ratio were assessed.

RESULTS: Both titanium and zirconia discs treated with Er:YAG laser resulted in visual surface alterations, but showed no significant change in average surface roughness (titanium P = 0.53, zirconia P = 0.34) or elemental-material-weight (titanium, P = 0.98), (zirconia, P = 0.96). No significant differences in biofilm biomass, average thickness, and live-to-dead bacteria ratio of laser-treated titanium and zirconia discs were identified compared to untreated groups (titanium P > 0.05, zirconia P > 0.05). Generally, zirconia discs presented with a lower live-to-dead bacteria ratio compared to titanium discs, regardless of laser treatment.

CONCLUSION: Er:YAG laser treatment of titanium and zirconia implant surfaces does not significantly affect surface roughness, elemental material weight, or early biofilm formation in the oral cavity.}, } @article {pmid36169983, year = {2022}, author = {Kreth, J and Koo, H and Diaz, PI}, title = {The functional oral microbiome: Biofilm environment, polymicrobial interactions, and community dynamics.}, journal = {Molecular oral microbiology}, volume = {37}, number = {5}, pages = {165-166}, doi = {10.1111/omi.12390}, pmid = {36169983}, issn = {2041-1014}, support = {R01 DE021726/DE/NIDCR NIH HHS/United States ; R21 DE029612/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; *Microbiota ; }, } @article {pmid36168277, year = {2023}, author = {Tibbits, G and Mohamed, A and Gelston, S and Flurin, L and Raval, YS and Greenwood-Quaintance, KE and Patel, R and Beyenal, H}, title = {Activity of a hypochlorous acid-producing electrochemical bandage as assessed with a porcine explant biofilm model.}, journal = {Biotechnology and bioengineering}, volume = {120}, number = {1}, pages = {250-259}, pmid = {36168277}, issn = {1097-0290}, support = {R01 AI091594/AI/NIAID NIH HHS/United States ; //U.S. Department of Health and Human Services/ ; }, mesh = {Swine ; Animals ; Hypochlorous Acid/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; Biofilms ; Bandages ; *Wound Infection/prevention & control ; Anti-Bacterial Agents/pharmacology ; }, abstract = {The activity of a hypochlorous acid-producing electrochemical bandage (e-bandage) in preventing methicillin-resistant Staphylococcus aureus infection (MRSA) infection and removing biofilms formed by MRSA was assessed using a porcine explant biofilm model. e-Bandages inhibited S. aureus infection (p = 0.029) after 12 h (h) of exposure and reduced 3-day biofilm viable cell counts after 6, 12, and 24 h exposures (p = 0.029). Needle-type microelectrodes were used to assess HOCl concentrations in explant tissue as a result of e-bandage treatment; toxicity associated with e-bandage treatment was evaluated. HOCl concentrations in infected and uninfected explant tissue varied between 30 and 80 µM, decreasing with increasing distance from the e-bandage. Eukaryotic cell viability was reduced by an average of 71% and 65% in fresh and day 3-old explants, respectively, when compared to explants exposed to nonpolarized e-bandages. HOCl e-bandages are a promising technology that can be further developed as an antibiotic-free treatment for wound biofilm infections.}, } @article {pmid36168027, year = {2022}, author = {Patel, H and Buchad, H and Gajjar, D}, title = {Pseudomonas aeruginosa persister cell formation upon antibiotic exposure in planktonic and biofilm state.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {16151}, pmid = {36168027}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; *Antitoxins/metabolism ; *Bacterial Infections ; Biofilms ; Ceftazidime/pharmacology ; Ciprofloxacin/metabolism/pharmacology ; Gentamicins/metabolism/pharmacology ; Humans ; Microbial Sensitivity Tests ; Plankton ; Pseudomonas aeruginosa ; }, abstract = {Persister cell (PC) is dormant, tolerant to antibiotics, and a transient reversible phenotype. These phenotypes are observed in P. aeruginosa and cause bacterial chronic infection as well as recurrence of biofilm-mediated infection. PC formation requires stringent response and toxin-antitoxin (TA) modules. This study shows the P. aeruginosa PC formation in planktonic and biofilm stages on ceftazidime, gentamicin, and ciprofloxacin treatments. The PC formation was studied using persister assay, flow cytometry using Redox Sensor Green, fluorescence as well as Confocal Laser Scanning Microscopy, and gene expression of stringent response and TA genes. In the planktonic stage, ceftazidime showed a high survival fraction, high redox activity, and elongation of cells was observed followed by ciprofloxacin and gentamicin treatment having redox activity and rod-shaped cells. The gene expression of stringent response and TA genes were upregulated on gentamicin followed by ceftazidime treatment and varied among the isolates. In the biofilm stage, gentamicin and ciprofloxacin showed the biphasic killing pattern, redox activity, gene expression level of stringent response and TA varied across the isolates. Ceftazidime treatment showed higher persister cells in planktonic growth while all three antibiotics were able to induce persister cell formation in the biofilm stage.}, } @article {pmid36167741, year = {2022}, author = {Gingichashvili, S and Steinberg, D and Sionov, RV and Feuerstein, O and Cohen, NE}, title = {An open-source computational tool for measuring bacterial biofilm morphology and growth kinetics upon one-sided exposure to an antimicrobial source.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {16125}, pmid = {36167741}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; *Anti-Infective Agents, Local/pharmacology ; Bacillus subtilis/physiology ; Biofilms ; Chlorhexidine/pharmacology ; Kinetics ; }, abstract = {Bacillus subtilis biofilms are well known for their complex and highly adaptive morphology. Indeed, their phenotypical diversity and intra-biofilm heterogeneity make this gram-positive bacterium the subject of many scientific papers on the structure of biofilms. The "robustness" of biofilms is a term often used to describe their level of susceptibility to antimicrobial agents and various mechanical and molecular inhibition/eradication methods. In this paper, we use computational analytics to quantify Bacillus subtilis morphological response to proximity to an antimicrobial source, in the form of the antiseptic chlorhexidine. Chlorhexidine droplets, placed in proximity to Bacillus subtilis macrocolonies at different distances result in morphological changes, quantified using Python-based code, which we have made publicly available. Our results quantify peripheral and inner core deformation as well as differences in cellular viability of the two regions. The results reveal that the inner core, which is often characterized by the presence of wrinkled formations in the macrocolony, is more preserved than the periphery. Furthermore, the paper describes a crescent-shaped colony morphology which occurs when the distance from the chlorhexidine source is 0.5 cm, as well as changes observed in the growth substrate of macrocolonies exposed to chlorhexidine.}, } @article {pmid36167127, year = {2023}, author = {Yan, H and Liu, C and Yu, W and Zhu, X and Chen, B}, title = {The aggregate distribution of Pseudomonas aeruginosa on biochar facilitates quorum sensing and biofilm formation.}, journal = {The Science of the total environment}, volume = {856}, number = {Pt 1}, pages = {159034}, doi = {10.1016/j.scitotenv.2022.159034}, pmid = {36167127}, issn = {1879-1026}, mesh = {*Quorum Sensing ; *Pseudomonas aeruginosa ; Bentonite ; Kaolin ; Biofilms ; Minerals ; Soil ; }, abstract = {Biochar when applied into soil, together with soil clay minerals, may provide habitats for soil microbes and shift soil microbial community structure. Although several mechanisms have been proposed to explain the effects of biochar on microbial community, the impact of biochar on quorum sensing (QS) and QS-regulated behavior is poorly understood. In this study, we compared the effects of biochar and three common soil minerals (i.e., montmorillonite, kaolinite, and goethite) on QS and biofilm formation. Pseudomonas aeruginosa PAO1 with complete QS systems was selected as a model organism. Our results showed that biochar and goethite effectively promoted microbial QS and biofilm formation, while montmorillonite and kaolinite posed no significant effect. Live/Dead staining, SEM and density-dependent QS activity indicated that biochar was beneficial to cell viability maintenance and cell aggregations, which improved the efficiency of intercellular communications through QS. QS mutant strain experiments confirmed that biochar enhanced PAO1 biofilm formation by promoting QS. Goethite promoted biofilm formation with a different mechanism that cell debris induced by iron ions and positive charge on goethite surface provided raw materials for bacterial biofilm formation. Our findings provide evidence that the presence of biochar can enhance QS and biofilm formation through a feedforward loop of the QS system. This contributes to better understand biochar-mediated microbial cell to cell communications through QS.}, } @article {pmid36165805, year = {2022}, author = {Sun, W and Shi, S and Chen, J and Zhao, W and Chen, T and Li, G and Zhang, K and Yu, B and Liu, D and Chen, Y and Ying, H and Ouyang, P}, title = {Blue Light Signaling Regulates Escherichia coli W1688 Biofilm Formation and l-Threonine Production.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0246022}, pmid = {36165805}, issn = {2165-0497}, mesh = {Humans ; Escherichia coli/genetics/metabolism ; Threonine/metabolism ; *Escherichia coli Infections ; *Escherichia coli Proteins/genetics/metabolism ; Biofilms ; }, abstract = {Escherichia coli biofilm may form naturally on biotic and abiotic surfaces; this represents a promising approach for efficient biochemical production in industrial fermentation. Recently, industrial exploitation of the advantages of optogenetics, such as simple operation, high spatiotemporal control, and programmability, for regulation of biofilm formation has garnered considerable attention. In this study, we used the blue light signaling-induced optogenetic system Magnet in an E. coli biofilm-based immobilized fermentation system to produce l-threonine in sufficient quantity. Blue light signaling significantly affected the phenotype of E. coli W1688. A series of biofilm-related experiments confirmed the inhibitory effect of blue light signaling on E. coli W1688 biofilm. Subsequently, a strain lacking a blue light-sensing protein (YcgF) was constructed via genetic engineering, which substantially reduced the inhibitory effect of blue light signaling on biofilm. A high-efficiency biofilm-forming system, Magnet, was constructed, which enhanced bacterial aggregation and biofilm formation. Furthermore, l-threonine production was increased from 10.12 to 16.57 g/L during immobilized fermentation, and the fermentation period was shortened by 6 h. IMPORTANCE We confirmed the mechanism underlying the inhibitory effects of blue light signaling on E. coli biofilm formation and constructed a strain lacking a blue light-sensing protein; this mitigated the aforementioned effects of blue light signaling and ensured normal fermentation performance. Furthermore, this study elucidated that the blue light signaling-induced optogenetic system Magnet effectively regulates E. coli biofilm formation and contributes to l-threonine production. This study not only enriches the mechanism of blue light signaling to regulate E. coli biofilm formation but also provides a theoretical basis and feasibility reference for the application of optogenetics technology in biofilm-based immobilized fermentation systems.}, } @article {pmid36162755, year = {2022}, author = {Ensafi, F and Fazlyab, M and Chiniforush, N and Akhavan, H}, title = {Comparative effects of SWEEPS technique and antimicrobial photodynamic therapy by using curcumin and nano-curcumin on Enterococcus faecalis biofilm in root canal treatment.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103130}, doi = {10.1016/j.pdpdt.2022.103130}, pmid = {36162755}, issn = {1873-1597}, mesh = {Humans ; Enterococcus faecalis ; *Photochemotherapy/methods ; Dental Pulp Cavity ; *Curcumin/pharmacology ; Photosensitizing Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Root Canal Irrigants/pharmacology ; Root Canal Preparation/methods ; }, abstract = {OBJECTIVES: This study aimed to compare the antimicrobial effects of the shock wave enhanced emission photoacoustic streaming (SWEEPS) technique and Antimicrobial photodynamic therapy (aPDT) with curcumin and nano-curcumin photosensitizers on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted teeth.

MATERIALS AND METHODS: This experimental study was conducted on extracted single-rooted human teeth. The teeth were decoronated at the cementoenamel junction, the root canals were instrumented with BioRace system, and their apices were sealed. Smear layer was removed, and the teeth were autoclave-sterilized. E. faecalis strains were cultured in sterile brain heart infusion (BHI) and a bacterial suspension with 0.5 McFarland standard concentration was prepared. The root canals were inoculated with the bacterial suspension and incubated at 37 °C for 4 weeks. The teeth were then divided into 12 groups (curcumin, nano-curcumin, curcumin + LED, nano-curcumin + LED, curcumin + SWEEPS, nano-curcumin + SWEEPS, curcumin + LED + SWEEPS, nano-curcumin + LED + SWEEPS, SWEEPS, positive control and negative control). The number of colony forming units (CFUs) was counted and analyzed by one-way ANOVA and Tukey's test.

RESULTS: A significant difference was noted in colony count among the groups (P<0.001). LED alone had the lowest and nano-curcumin + LED + SWEEPS had the highest root canal cleaning efficacy. SWEEPS along with curcumin, nano-curcumin, and LED significantly decreased the bacterial count compared with other groups (P<0.05).

CONCLUSION: Application of the SWEEPS technique with curcumin and nano-curcumin as photosensitizer activated by LED in aPDT improved the reduction of E. faecalis in root canals.}, } @article {pmid36162133, year = {2022}, author = {Feng, W and Yang, J and Ma, Y and Liu, Y and Yin, R and Qiao, Z and Ji, Y and Zhou, Y}, title = {Correlation between SAP2 and CAP1 in clinical strains of Candida albicans at planktonic and biofilm states.}, journal = {Canadian journal of microbiology}, volume = {68}, number = {12}, pages = {722-730}, doi = {10.1139/cjm-2022-0139}, pmid = {36162133}, issn = {1480-3275}, mesh = {*Candida albicans/genetics ; *Fungal Proteins/genetics/metabolism ; Plankton ; Itraconazole ; Biofilms ; Antifungal Agents/pharmacology ; }, abstract = {This study aimed to explore the influences of SAP2 and CAP1 on itraconazole (ITR) resistance of Candida albicans at different states. A total of 10 ITR-resistant strains and 10 ITR-sensitive strains were used for SAP2 sequencing and CAP1 sequencing. SAP2 sequencing showed no missense mutation, and three synonymous mutations. CAP1 gene sequencing identified two missense mutations M140I (8) and K191Q (4), and 14 synonymous mutations G201A (1), A246C (5), C282T (6), G288A (6), C321T (7), A399C (16), C432T (16), C465T (11), G552A (16), G669T (1), G672A (1), G681T (2), T783C (1), and T819A (2). The biofilm formation capacity of resistant C. albicans strains, including the CAP1∆/∆ strain, was stronger. Afterward, real-time quantitative PCR was used to analyze the expression of SAP2 and CAP1. Compared with the sensitive strains, SAP2 and CAP1 expressions were both significantly upregulated in resistant strains at planktonic and biofilm states (P < 0.05). Compared with the strains at planktonic state, SAP2 was significantly upregulated, while CAP1 was significantly downregulated at biofilm states (P < 0.05). Additionally, SAP2 expression in the CAP1 knocked down strain of C. albicans was significantly upregulated, and SAP2 expression was evidently downregulated in the CAP1∆/∆ strain at biofilm states compared with that at planktonic states (P < 0.05). Loss of CAP1 can increase SAP2 level and may influence the biofilm formation of C. albicans, thus increasing ITR resistance ofC. albicans.}, } @article {pmid36159056, year = {2022}, author = {Mosayebi, N and Toodehzaeim, MH and Zandi, H and Joshan, N and Haerian, A}, title = {Evaluation of the effects of fluoride mouth rinse and varnish on the early biofilm formation of Streptococcus mutans in two types of orthodontic adhesive resins: An in vitro study.}, journal = {Dental research journal}, volume = {19}, number = {}, pages = {54}, pmid = {36159056}, issn = {1735-3327}, abstract = {BACKGROUND: The aim of the present study is to compare the antibacterial effect of fluoride mouth rinse and fluoride varnish on the primary biofilm formation of Streptococcus mutans (S. mutans) in two types of orthodontic adhesives.

MATERIALS AND METHODS: This is an in vitro study in which forty composite discs of Transbond XT and Lightbond were divided randomly into 4 groups: Group 1: Control group (not treated with fluoride), Group 2: Rinsed by 0.2% fluoride mouth rinse, Group 3: Rinsed by 0.05% fluoride mouth rinse, and Group 4: Treated by varnish fluoride. Then each group was placed in S. mutans suspension. Bacterial suspension from each treatment was subcultured onto the surface of Mueller-Hinton agar plates, and bacterial growth was assessed. The results were analyzed by analysis of variance test and Scheffé test was run to compute the binary groups (P < 0.05).

RESULTS: There was a statistically significant reduction in the viability of S. mutans in treated groups by fluoride but no significant difference between two types of composites.

CONCLUSION: The results of this study demonstrated that S. mutans colonies were sensitive to fluoride and their most effective form was varnish. There was no significant difference in early biofilm formation of S. mutans in two types of orthodontic adhesive resins Transbond XT and Lightbond.}, } @article {pmid36155861, year = {2022}, author = {Yang, SQ and Zhou, HJ and Teng, LP and Zeng, H}, title = {Streptomyces: Derived Active Extract Inhibits Candida albicans Biofilm Formation.}, journal = {Current microbiology}, volume = {79}, number = {11}, pages = {332}, pmid = {36155861}, issn = {1432-0991}, support = {AD22035111//AD22035111/ ; }, mesh = {*Anti-Infective Agents/pharmacology ; Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; Plant Extracts/pharmacology ; *Streptomyces ; }, abstract = {Candida albicans is an opportunistic pathogen that causes biofilm-associated infections. C. albicans biofilms are known to display reduced susceptibility to antimicrobials and high rates of acquired antibiotic resistance, and biofilm forming in C. albicans further hampers treatment options and highlights the need for new antibiofilm strategies. Identifying active components from desert actinomycetes strains to inhibit the formation of C. albicans biofilms represents an effective treatment strategy. In this study, actinomycetes that can inhibit C. albicans biofilm formation were isolated from the Taklimakan Desert, and the underlying mechanisms were explored. After screening the anti-C.albicans biofilm activities of culture supernatants from 170 Actinomycete strains, six strains showed significant inhibition of C. albicans biofilm formation. Microscopic examination showed a reduction in biofilm formation of C. albicans treated with supernatants from actinomycetes. Scanning electron microscopy showed that the morphological changes in biofilm cells were caused by cell membrane rupture and cell material leakage. Then, C.albicans biofilms were destroyed by changing the content of extracellular polysaccharides or degrading extracellular DNA. Finally, a preliminary study on active substances extracted from a new species (TRM43335) showed that the substances that inhibited the formation of biofilms might be peptides. This study provides preliminary evidence that desert actinomyces strains have inhibitory effects on the biofilm development of C. albicans.}, } @article {pmid36155066, year = {2022}, author = {Pesset, CM and Fonseca, COD and Antunes, M and Santos, ALLD and Teixeira, IM and Ribeiro, TAN and Sachs, D and Penna, B}, title = {Characterizing biofilm formation of Staphylococcus pseudintermedius in different suture materials.}, journal = {Microbial pathogenesis}, volume = {172}, number = {}, pages = {105796}, doi = {10.1016/j.micpath.2022.105796}, pmid = {36155066}, issn = {1096-1208}, mesh = {Dogs ; Animals ; Nylons ; Polypropylenes ; Polyglactin 910 ; Biofilms ; Sutures ; *Dog Diseases/microbiology ; *Staphylococcal Infections/veterinary/microbiology ; Anti-Bacterial Agents ; }, abstract = {Staphylococcus pseudintermedius is the primary cause of pyoderma and surgical site infection (SSI) in dogs, and biofilm formation is the main reason for persistent SSI. The presence of biofilm in medical devices can directly impact treatment. Methicillin-resistant S. pseudintermedius (MRSP) emerged rapidly in companion animals, limiting treatment options. MRSP is a public health problem since zoonotic transmission can occur. The study seeks to evaluate biofilm formation capacity via Staphylococcus pseudintermedius collected from dogs affected by topical infections, in suture materials commonly used in companion animal surgery. We tested segments of four types of sutures. Biofilm production was measured by staining with safranin and colorimetric absorbance measurement. We calculated colony-forming units (CFUs) for each type of sutures and visualized biofilm via Scanning Electron Microscopy (SEM) images. The genes associated with biofilm formation (icaA and icaD) were identified using PCR. The colorimetric tests showed that the biofilm is most abundantly formed on the cotton sutures and polyglactin 910. The ability to form biofilm on polypropylene and nylon sutures has also been demonstrated, although at varying intensities. PCR revealed the presence of the two genes (icaA and icaD) in all the isolates. We used a positive control using a reference strain and negative control without bacteria for comparisons. Suture material allowing biofilm formation makes it difficult to prevent and treat surgical site infections. Therefore, it is important to know which suture thread is more susceptible to biofilm formation by bacteria to prevent possible secondary infections at surgical sites.}, } @article {pmid36154759, year = {2022}, author = {da Silva, NDG and de Paiva, PRB and Magalhães, TVM and Braga, AS and Santos, PSDS and Henrique-Silva, F and Magalhães, AC and Buzalaf, MAR}, title = {Effect of experimental and commercial artificial saliva formulations on the activity and viability of microcosm biofilm and on enamel demineralization for irradiated patients with head and neck cancer (HNC).}, journal = {Biofouling}, volume = {38}, number = {7}, pages = {674-686}, doi = {10.1080/08927014.2022.2111258}, pmid = {36154759}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Carboxymethylcellulose Sodium/pharmacology ; Chlorhexidine/pharmacology ; *Dental Caries ; *Head and Neck Neoplasms ; Humans ; Male ; Phosphates/pharmacology ; Saliva/microbiology ; Saliva, Artificial/pharmacology ; Sucrose/pharmacology ; *Tooth Demineralization/microbiology ; }, abstract = {The effect of different artificial saliva formulations on biofilm activity and viability, and on enamel demineralization for head and neck cancer (HNC) patients was evaluated. Irradiated enamel samples were treated (1 min) with BioXtra® or with experimental formulations containing carboxymethylcellulose plus inorganic constituents alone (AS) or containing 0.1 mg mL[-1] CaneCPI-5 (AS + Cane), 1.0 mg mL[-1] hemoglobin (AS + Hb) or combination of both (AS + Cane + Hb). Phosphate-buffered-saline and chlorhexidine (0.12%) were negative and positive control, respectively. Biofilm was produced from the saliva of five male HNC patients, under 0.2% sucrose exposure for 5 days, and daily treated with the formulations (1 min). No significant effects were observed for the different experimental treatments. BioXtra[®] significantly reduced lactobacilli, demonstrating antibacterial potential for this group. Chlorhexidine was an effective treatment to significantly reduce all parameters, being an important antimicrobial and anticaries agent. Future in vitro studies must be performed using a new approach for the design of the experimental formulations.}, } @article {pmid36154360, year = {2022}, author = {Prentice, JA and Bridges, AA and Bassler, BL}, title = {Synergy between c-di-GMP and Quorum-Sensing Signaling in Vibrio cholerae Biofilm Morphogenesis.}, journal = {Journal of bacteriology}, volume = {204}, number = {10}, pages = {e0024922}, pmid = {36154360}, issn = {1098-5530}, support = {MCB-2043238//National Science Foundation (NSF)/ ; /HHMI/Howard Hughes Medical Institute/United States ; 2R37GM065859//HHS | NIH | National Institute of General Medical Sciences (NIGMS)/ ; R37 GM065859/GM/NIGMS NIH HHS/United States ; 1K99AI158939//HHS | NIH | NIAID | Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases (DMID)/ ; }, mesh = {*Vibrio cholerae/metabolism ; Quorum Sensing/physiology ; Cyclic GMP/metabolism ; Biofilms ; Spermidine/metabolism ; Transcription Factors/metabolism ; Morphogenesis ; Gene Expression Regulation, Bacterial ; Bacterial Proteins/metabolism ; }, abstract = {Transitions between individual and communal lifestyles allow bacteria to adapt to changing environments. Bacteria must integrate information encoded in multiple sensory cues to appropriately undertake these transitions. Here, we investigate how two prevalent sensory inputs converge on biofilm morphogenesis: quorum sensing, which endows bacteria with the ability to communicate and coordinate group behaviors, and second messenger c-di-GMP signaling, which allows bacteria to detect and respond to environmental stimuli. We use Vibrio cholerae as our model system, the autoinducer AI-2 to modulate quorum sensing, and the polyamine norspermidine to modulate NspS-MbaA-mediated c-di-GMP production. Individually, AI-2 and norspermidine drive opposing biofilm phenotypes, with AI-2 repressing and norspermidine inducing biofilm formation. Surprisingly, however, when AI-2 and norspermidine are simultaneously detected, they act synergistically to increase biofilm biomass and biofilm cell density. We show that this effect is caused by quorum-sensing-mediated activation of nspS-mbaA expression, which increases the levels of NspS and MbaA, and in turn, c-di-GMP biosynthesis, in response to norspermidine. Increased MbaA-synthesized c-di-GMP activates the VpsR transcription factor, driving elevated expression of genes encoding key biofilm matrix components. Thus, in the context of biofilm morphogenesis in V. cholerae, quorum-sensing regulation of c-di-GMP-metabolizing receptor levels connects changes in cell population density to detection of environmental stimuli. IMPORTANCE The development of multicellular communities, known as biofilms, facilitates beneficial functions of gut microbiome bacteria and makes bacterial pathogens recalcitrant to treatment. Understanding how bacteria regulate the biofilm life cycle is fundamental to biofilm control in industrial processes and in medicine. Here, we demonstrate how two major sensory inputs-quorum-sensing communication and second messenger c-di-GMP signaling-jointly regulate biofilm morphogenesis in the global pathogen Vibrio cholerae. We characterize the mechanism underlying a surprising synergy between quorum-sensing and c-di-GMP signaling in controlling biofilm development. Thus, the work connects changes in cell population density to detection of environmental stimuli in a pathogen of clinical significance.}, } @article {pmid36151798, year = {2022}, author = {Zhao, H and Shi, T and Li, F and Wang, R and Lu, F and Huang, Z}, title = {[Advance of in vitro oral static biofilm model].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {38}, number = {9}, pages = {3267-3278}, doi = {10.13345/j.cjb.210921}, pmid = {36151798}, issn = {1872-2075}, mesh = {*Biofilms ; Reproducibility of Results ; }, abstract = {Oral static biofilm model is an important tool for in vitro simulation of oral microecological environment, which has become an important method for studying the pathogenesis of various oral diseases and testing the efficacy of various drugs, oral care products and foods due to its low cost, high throughput, good reliability and easy operation. The establishment of oral static biofilm models allows the selection of different devices, inoculum sources, media, substrates and culture conditions according to the purpose of the study, and the evaluation of biofilm growth by various methods such as measuring biomass, metabolic activity, community structure and performing visualization analysis. This paper summarizes the methodological elements reported in recent years for the establishment and evaluation of oral static biofilm models, and analyzes and discusses the applicability of various methods in the hope of contributing to the research and production practice in related fields.}, } @article {pmid36151756, year = {2022}, author = {Wen, X and Huang, J and Zeng, G and Liu, D and Chen, S}, title = {Microbial activity along the depth of biofilm in the simultaneous partial nitrification, anammox and denitrification (SNAD) system.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-8}, doi = {10.1080/09593330.2022.2128889}, pmid = {36151756}, issn = {1479-487X}, abstract = {Simultaneous partial nitrification, anammox and denitrification (SNAD) is a sustainable and cost-effective technology for nitrogen removal from low-strength wastewater. However, knowledge of the biofilm microenvironment of the SNAD system is currently unsatisfactory. The purpose of this study was to evaluate organic carbon effects on the microenvironment and microbial growth in the SNAD biofilm system. Microelectrodes were used to investigate microbial activity in-depth within biofilms. ORP distribution of the SNAD system was positively related to anammox activity(R[2 ]= 0.9), and had some influence on microbial community structure. The synergistic effect of anammox bacteria and denitrifiers could be achieved when the abundance ratio of anammox bacteria to denitrifying bacteria is greater than 1.2.}, } @article {pmid36150625, year = {2022}, author = {Haque, MM and Haque, MA and Mosharaf, MK and Islam, MS and Islam, MM and Hasan, M and Molla, AH and Haque, MA}, title = {Biofilm-mediated decolorization, degradation and detoxification of synthetic effluent by novel biofilm-producing bacteria isolated from textile dyeing effluent.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {314}, number = {}, pages = {120237}, doi = {10.1016/j.envpol.2022.120237}, pmid = {36150625}, issn = {1873-6424}, mesh = {Wastewater/chemistry ; Congo Red ; Azo Compounds/chemistry ; Laccase ; Glycerol ; Xenobiotics ; Biodegradation, Environmental ; Coloring Agents/chemistry ; Textiles ; Biofilms ; *Environmental Pollutants/analysis ; *Nucleic Acids ; Lipids ; }, abstract = {Biofilm-mediated bioremediation of xenobiotic pollutants is an environmental friendly biological technique. In this study, 36 out of 55 bacterial isolates developed biofilms in glass test tubes containing salt-optimized broth plus 2% glycerol (SOBG). Scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and Congo red- and Calcofluor binding results showed biofilm matrices contain proteins, curli, nanocellulose-rich polysaccharides, nucleic acids, lipids, and peptidoglycans. Several functional groups including -OH, N-H, C-H, CO, COO[-], -NH2, PO, C-O, and C-C were also predicted. By sequencing, ten novel biofilm-producing bacteria (BPB) were identified, including Exiguobacterium indicum ES31G, Kurthia gibsonii ES43G, Kluyvera cryocrescens ES45G, Cedecea lapagei ES48G, Enterobacter wuhouensis ES49G, Aeromonas caviae ES50G, Lysinibacillus sphaericus ES51G, Acinetobacter haemolyticus ES52G, Enterobacter soli ES53G, and Comamonas aquatica ES54G. The Direct Red (DR) 28 (a carcinogenic and mutagenic dye used in dyeing and biomedical processes) decolorization process was optimized in selected bacterial isolates. Under optimum conditions (SOBG medium, 75 mg L[-1] dye, pH 7, 28 °C, microaerophilic condition and within 72 h of incubation), five of the bacteria tested could decolorize 97.8% ± 0.56-99.7% ± 0.45 of DR 28 dye. Azoreductase and laccase enzymes responsible for biodegradation were produced under the optimum condition. UV-Vis spectral analysis revealed that the azo (-NN-) bond peak at 476 nm had almost disappeared in all of the decolorized samples. FTIR data revealed that the foremost characteristic peaks had either partly or entirely vanished or were malformed or stretched. The chemical oxygen demand decreased by 83.3-91.3% in the decolorized samples, while plant probiotic bacterial growth was indistinguishable in the biodegraded metabolites and the original dye. Furthermore, seed germination (%) was higher in the biodegraded metabolites than the parent dye. Thus, examined BPB could provide potential solutions for the bioremediation of industrial dyes in wastewater.}, } @article {pmid36150557, year = {2022}, author = {Lima, LS and Ramalho, SR and Sandim, GC and Parisotto, EB and Orlandi Sardi, JC and Rodrigues Macedo, ML}, title = {Prevention of hospital pathogen biofilm formation by antimicrobial peptide KWI18.}, journal = {Microbial pathogenesis}, volume = {172}, number = {}, pages = {105791}, doi = {10.1016/j.micpath.2022.105791}, pmid = {36150557}, issn = {1096-1208}, mesh = {*Antimicrobial Peptides ; Biofilms ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Hospitals ; Ergosterol/pharmacology ; Sorbitol/pharmacology ; }, abstract = {This study investigated the antimicrobial and antibiofilm activity of KWI18, a new synthetic peptide. KWI18 was tested against planktonic cells and Pseudomonas aeruginosa and Candida parapsilosis biofilms. Time-kill and synergism assays were performed. Sorbitol, ergosterol, lipid peroxidation, and protein oxidation assays were used to gain insight into the mechanism of action of the peptide. Toxicity was evaluated against erythrocytes and Galleria mellonella. KWI18 showed antimicrobial activity, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 10 μM. KWI18 at 10 × MIC reduced P. aeruginosa and C. parapsilosis biofilm formation and cell viability. Time-kill assays revealed that KWI18 inhibited the growth of P. aeruginosa in 4 h and that of C. parapsilosis in 6 h. The mechanism of action was related to ergosterol as well as induction of oxidative damage in cells and biofilms. Furthermore, KWI18 demonstrated low toxicity to erythrocytes and G. mellonella. KWI18 proved to be an effective antibiofilm agent, opening opportunities for the development of new antimicrobials.}, } @article {pmid36148855, year = {2023}, author = {Robberecht, L and Delattre, J and Meire, M}, title = {Isthmus morphology influences debridement efficacy of activated irrigation: A laboratory study involving biofilm mimicking hydrogel removal and high-speed imaging.}, journal = {International endodontic journal}, volume = {56}, number = {1}, pages = {118-127}, pmid = {36148855}, issn = {1365-2591}, support = {ULNE/ANR-16-IDEX-0004//Programme Investissement d'Avenir (French Government)/ ; }, mesh = {*Hydrogels ; *Root Canal Irrigants ; Lasers, Solid-State ; Debridement ; Root Canal Therapy ; *Dental Pulp Cavity ; }, abstract = {AIM: Little is known about the influence of isthmus morphology on the debridement efficacy of activated irrigation. The aim of this study was to investigate the influence of isthmus morphology on the debridement efficacy of laser-activated irrigation (LAI), EDDY and needle irrigation (NI), and to explain the methods of isthmus cleaning by LAI and EDDY.

METHODOLOGY: Four root canal models (apical diameter: 0.30 mm, taper: 0.06, curvature: 23°, length: 20 mm) were produced by CAD-CAM with different isthmus morphologies: long-wide (4 mm; 0.4 mm), long-narrow (4 mm; 0.15 mm), short-wide (2 mm; 0.4 mm) and short-narrow (2 mm; 0.15 mm). The isthmuses were filled with a hydrogel containing dentine debris. The canals were filled with irrigant and models were assigned to the following irrigation protocols (n = 240): needle irrigation (NI) with a 30G needle, Eddy, and LAI (2940 nm Er:YAG-laser, 15 Hz, 40 mJ, SWEEPS, tip at the canal entrance). Standardized images of the isthmuses were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Kruskal-Wallis test followed by Dunn's multiple comparison. Visualization of the isthmus during activation was achieved using a high-speed camera. The pattern and speed of the flow in the isthmus as well as transient and stable cavitation were analysed using imaging software.

RESULTS: Laser-activated irrigation, EDDY and NI removed more hydrogel in short-wide isthmuses than in narrow isthmuses (p < .001). LAI and EDDY removed more hydrogel than NI in every isthmus configuration (p < .001). EDDY showed eddies and stable cavitation, and LAI showed transient cavitation at each pulse, and pulsed horizontal flow with the highest particle speed in closed short isthmuses.

CONCLUSIONS: Isthmus morphology influences debridement in all irrigation groups. Short-wide isthmuses were the easiest to clean while narrow isthmuses were the most challenging to clean. Width seems to be a more critical anatomical parameter than length. LAI and EDDY resulted in the greatest biofilm removal and performed better than NI. EDDY produced eddies and stable cavitation in the isthmus, and LAI showed transient cavitation and pulsed horizontal flow.}, } @article {pmid36148767, year = {2022}, author = {Wanicharat, W and Wanachantararak, P and Poomanee, W and Leelapornpisid, P and Leelapornpisid, W}, title = {Potential of Bouea macrophylla kernel extract as an intracanal medicament against mixed-species bacterial-fungal biofilm. An in vitro and ex vivo study.}, journal = {Archives of oral biology}, volume = {143}, number = {}, pages = {105539}, doi = {10.1016/j.archoralbio.2022.105539}, pmid = {36148767}, issn = {1879-1506}, mesh = {Bacteria ; Biofilms ; *Calcium Hydroxide/pharmacology ; Candida albicans ; *Chlorhexidine/pharmacology ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis ; Plant Extracts/pharmacology ; Root Canal Irrigants/pharmacology ; Saline Solution/pharmacology ; }, abstract = {OBJECTIVE: To investigate the antimicrobial activity of B. macrophylla kernel extract against mixed-species biofilms of E. faecalis, S. gordonii and C. albicans in vitro. To evaluate the efficacy of the extract as an intracanal medicament compared with Ca(OH)2 and chlorhexidine in ex vivo tooth model.

METHODS: The antibiofilm effect of B. macrophylla kernel extract was determined by AlamarBlue™ assay and the effect on biofilms was visualized by LIVE/DEAD® BacLight™ viability test. Mixed-species biofilms were incubated into the tooth model (N = 42) for 21 days. The teeth were randomly divided into 4 medicament groups for 7 days: (i) normal saline, (ii) calcium hydroxide (Ca(OH)2), (iii) chlorhexidine gel, (iv) B. macrophylla kernel extract. Dentine samples were collected, qPCR with PMA was used to quantify the viability and species composition of each sample. SEM was used to visualize the effect of medicament on biofilm structure.

RESULTS: The MBIC was 6.25 mg/mL and the MBEC was 50 mg/mL. The integrity of microbial cells was progressively compromised as concentration increased, resulting in greater cell death. Ex vivo tooth model revealed that biofilm treated with 50 mg/mL of the B. macrophylla extract demonstrated a significantly higher proportions of dead cells than in Ca(OH)2, chlorhexidine and normal saline groups (p < 0.01). Disruption of biofilm structure and enlargement of dentinal tubules was observed in B. macrophylla group on SEM.

CONCLUSION: The extract of B. macrophylla kernel exhibited significant antibiofilm effect against the mixed-species biofilms of E. faecalis, S. gordonii and C. albicans.}, } @article {pmid36148433, year = {2022}, author = {Porter, M and Davidson, FA and MacPhee, CE and Stanley-Wall, NR}, title = {Systematic microscopical analysis reveals obligate synergy between extracellular matrix components during Bacillus subtilis colony biofilm development.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100082}, pmid = {36148433}, issn = {2590-2075}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Single-species bacterial colony biofilms often present recurring morphologies that are thought to be of benefit to the population of cells within and are known to be dependent on the self-produced extracellular matrix. However, much remains unknown in terms of the developmental process at the single cell level. Here, we design and implement systematic time-lapse imaging and quantitative analyses of the growth of Bacillus subtilis colony biofilms. We follow the development from the initial deposition of founding cells through to the formation of large-scale complex structures. Using the model biofilm strain NCIB 3610, we examine the movement dynamics of the growing biomass and compare them with those displayed by a suite of otherwise isogenic matrix-mutant strains. Correspondingly, we assess the impact of an incomplete matrix on biofilm morphologies and sessile growth rate. Our results indicate that radial expansion of colony biofilms results from the division of bacteria at the biofilm periphery rather than being driven by swelling due to fluid intake. Moreover, we show that lack of exopolysaccharide production has a negative impact on cell division rate, and the extracellular matrix components act synergistically to give the biomass the structural strength to produce aerial protrusions and agar substrate-deforming ability.}, } @article {pmid36147852, year = {2022}, author = {de Almeida, OGG and Pereira, MG and Oxaran, V and De Martinis, ECP and Alves, VF}, title = {In silico metatranscriptomic approach for tracking biofilm-related effectors in dairies and its importance for improving food safety.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {928480}, pmid = {36147852}, issn = {1664-302X}, abstract = {Sessile microorganisms are usually recalcitrant to antimicrobial treatments, and it is possible that finding biofilm-related effectors in metatranscriptomics datasets helps to understand mechanisms for bacterial persistence in diverse environments, by revealing protein-encoding genes that are expressed in situ. For this research, selected dairy-associated metatranscriptomics bioprojects were downloaded from the public databases JGI GOLD and NCBI (eight milk and 45 cheese samples), to screen for sequences encoding biofilm-related effectors. Based on the literature, the selected genetic determinants were related to adhesins, BAP, flagellum-related, intraspecific QS (AHL, HK, and RR), interspecific QS (LuxS), and QQ (AHL-acylases, AHL-lactonases). To search for the mRNA sequences encoding for those effector proteins, a custom database was built from UniprotKB, yielding 1,154,446 de-replicated sequences that were indexed in DIAMOND for alignment. The results revealed that in all the dairy-associated metatranscriptomic datasets obtained, there were reads assigned to genes involved with flagella, adhesion, and QS/QQ, but BAP-reads were found only for milk. Significant Pearson correlations (p < 0.05) were observed for transcripts encoding for flagella, RR, histidine kinases, adhesins, and LuxS, although no other significant correlations were found. In conclusion, the rationale used in this study was useful to demonstrate the presence of biofilm-associated effectors in metatranscriptomics datasets, pointing out to possible regulatory mechanisms in action in dairy-related biofilms, which could be targeted in the future to improve food safety.}, } @article {pmid36147840, year = {2022}, author = {Gu, K and Ouyang, P and Hong, Y and Dai, Y and Tang, T and He, C and Shu, G and Liang, X and Tang, H and Zhu, L and Xu, Z and Yin, L}, title = {Geraniol inhibits biofilm formation of methicillin-resistant Staphylococcus aureus and increase the therapeutic effect of vancomycin in vivo.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {960728}, pmid = {36147840}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is among the common drug resistant bacteria, which has gained worldwide attention due to its high drug resistance and infection rates. Biofilms produced by S. aureus are known to increase antibiotic resistance, making the treatment of S. aureus infections even more challenging. Hence, inhibition of biofilm formation has become an alternative strategy for controlling persistent infections. In this study, we evaluated the efficacy of geraniol as a treatment for MRSA biofilm infection. The results of crystal violet staining indicated that 256 μg/mL concentration of geraniol inhibited USA300 biofilm formation by 86.13% and removed mature biofilms by 49.87%. Geraniol exerted its anti-biofilm effect by influencing the major components of the MRSA biofilm structure. We found that geraniol inhibited the synthesis of major virulence factors, including staphyloxanthin and autolysins. The colony count revealed that geraniol inhibited staphyloxanthin and sensitized USA300 cells to hydrogen peroxide. Interestingly, geraniol not only reduced the release of extracellular nucleic acids (eDNA) but also inhibited cell autolysis. Real-time polymerase chain reaction data revealed the downregulation of genes involved in biofilm formation, which verified the results of the phenotypic analysis. Geraniol increased the effect of vancomycin in eliminating USA300 biofilms in a mouse infection model. Our findings revealed that geraniol effectively inhibits biofilm formation in vitro. Furthermore, in combination with vancomycin, geraniol can reduce the biofilm adhesion to the implant in mice. This suggests the potential of geraniol as an anti-MRSA biofilm drug and can provide a solution for the clinical treatment of biofilm infection.}, } @article {pmid36147327, year = {2022}, author = {Liu, Y and Su, S and Yu, M and Zhai, D and Hou, Y and Zhao, H and Ma, X and Jia, M and Xue, X and Li, M}, title = {Pyrancoumarin derivative LP4C targeting of pyrimidine de novo synthesis pathway inhibits MRSA biofilm and virulence.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {959736}, pmid = {36147327}, issn = {1663-9812}, abstract = {Staphylococcus aureus poses a serious public health threat because of its multidrug resistance and biofilm formation ability. Hence, developing novel anti-biofilm agents and finding targets are needed to mitigate the proliferation of drug-resistant pathogens. In our previous study, we showed that the pyrancoumarin derivative 2-amino-4-(2,6-dichlorophenyl)-3-cyano-5-oxo-4H, 5H- pyrano [3,2c] chromene (LP4C) can destroy the biofilm of methicillin-resistant S. aureus (MRSA) in vitro and in vivo. Here, we further explored the possible mechanism of LP4C as a potential anti-biofilm drug. We found that LP4C inhibits the expression of enzymes involved in the de novo pyrimidine pathway and attenuates the virulence of MRSA USA300 strain without affecting the agr or luxS quorum sensing system. The molecular docking results indicated that LP4C forms interactions with the key amino acid residues of pyrR protein, which functions as the important regulator of bacterial pyrimidine synthesis. These findings reveal that pyrancoumarin derivative LP4C inhibits MRSA biofilm formation and targeting pyrimidine de novo synthesis pathway.}, } @article {pmid36146003, year = {2022}, author = {Sarfraz, S and Mäntynen, PH and Laurila, M and Rossi, S and Leikola, J and Kaakinen, M and Suojanen, J and Reunanen, J}, title = {Comparison of Titanium and PEEK Medical Plastic Implant Materials for Their Bacterial Biofilm Formation Properties.}, journal = {Polymers}, volume = {14}, number = {18}, pages = {}, pmid = {36146003}, issn = {2073-4360}, support = {243032491//Academy of Finland/ ; 200230071//Helsinki University Hospital/ ; }, abstract = {This study investigated two of the most commonly used CAD-CAM materials for patient-specific reconstruction in craniomaxillofacial surgery. The aim of this study was to access the biofilm formation of Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Escherichia coli on titanium and PEEK medical implant materials. Two titanium specimens (titanium grade 2 tooled with a Planmeca CAD-CAM milling device and titanium grade 5 tooled with a computer-aided design direct metal laser sintering device (CAD-DMLS)) and one PEEK specimen tooled with a Planmeca CAD-CAM milling device were studied. Bacterial adhesion on implants was evaluated in two groups (saliva-treated group and non-saliva-treated group) to imitate intraoral and extraoral surgical routes for implant placement. The PEEK medical implant material showed higher bacterial adhesion by S. aureus, S. mutans, and E. coli than titanium grade 2 and titanium grade 5, whereas E. faecalis showed higher adhesion to titanium as compared to PEEK. Saliva contamination of implants also effected bacterial attachment. Salivary coating enhanced biofilm formation by S. aureus, S. mutans, and E. faecalis. In conclusion, our findings imply that regardless of the implant material type or tooling techniques used, salivary coating plays a vital role in bacterial adhesion. In addition, the majority of the bacterial strains showed higher adhesion to PEEK than titanium.}, } @article {pmid36145988, year = {2022}, author = {Roy, PK and Park, SH and Song, MG and Park, SY}, title = {Antimicrobial Efficacy of Quercetin against Vibrio parahaemolyticus Biofilm on Food Surfaces and Downregulation of Virulence Genes.}, journal = {Polymers}, volume = {14}, number = {18}, pages = {}, pmid = {36145988}, issn = {2073-4360}, support = {2021R1I1A3A04037468//National Research Foundation of Korea/ ; }, abstract = {For the seafood industry, Vibrio parahaemolyticus, one of the most prevalent food-borne pathogenic bacteria that forms biofilms, is a constant cause of concern. There are numerous techniques used throughout the food supply chain to manage biofilms, but none are entirely effective. Through assessing its antioxidant and antibacterial properties, quercetin will be evaluated for its ability to prevent the growth of V. parahaemolyticus biofilm on shrimp and crab shell surfaces. With a minimum inhibitory concentration (MIC) of 220 µg/mL, the tested quercetin exhibited the lowest bactericidal action without visible growth of bacteria. In contrast, during various experiments in this work, the inhibitory efficacy of quercetin without (control) and with sub-MICs levels (1/2, 1/4, and 1/8 MIC) against V. parahaemolyticus was examined. With increasing quercetin concentration, swarming and swimming motility, biofilm formation, and expression levels of related genes linked to flagella motility (flaA and flgL), biofilm formation (vp0952 and vp0962), and quorum-sensing (luxS and aphA) were all dramatically reduced (p < 0.05). Quercetin (0−110 μg/mL) was investigated on shrimp and crab shell surfaces, the inhibitory effects were 0.68−3.70 and 0.74−3.09 log CFU/cm2, respectively (p < 0.05). The findings were verified using field emission scanning electron microscopy (FE-SEM), which revealed quercetin prevented the development of biofilms by severing cell-to-cell contacts and induced cell lysis, which resulted in the loss of normal cell shape. Furthermore, there was a substantial difference in motility between the treatment and control groups (swimming and swarming). According to our findings, plant-derived quercetin should be used as an antimicrobial agent in the food industry to inhibit the establishment of V. parahaemolyticus biofilms. These findings suggest that bacterial targets are of interest for biofilm reduction with alternative natural food agents in the seafood sector along the entire food production chain.}, } @article {pmid36145527, year = {2022}, author = {Voit, M and Trampuz, A and Gonzalez Moreno, M}, title = {In Vitro Evaluation of Five Newly Isolated Bacteriophages against E. faecalis Biofilm for Their Potential Use against Post-Treatment Apical Periodontitis.}, journal = {Pharmaceutics}, volume = {14}, number = {9}, pages = {}, pmid = {36145527}, issn = {1999-4923}, abstract = {State-of-the-art treatment of root canal infection includes the use of mechanical debridement and chemical agents. This disinfection method is limited, and microorganisms can remain in the canal system. Enterococcus faecalis appears with a high prevalence in secondary and persistent root canal infections and can be linked to endodontic treatment failure due to its various resistance mechanisms. Here, we evaluated the activity of newly isolated bacteriophages against clinical isolates of E. faecalis (including one vancomycin- and gentamicin-resistant strain) as a single treatment or in combination with gentamicin and vancomycin. For the resistant strain, daptomycin and fosfomycin were tested. Sixteen E. faecalis strains were used to screen for the presence of bacteriophages in sewage. Five different bacteriophages were characterized in terms of virion morphology, host range and killing-kinetics against each E. faecalis host strain. To investigate the antibiofilm effect of antibiotic and phages, E. faecalis biofilm was grown on porous glass beads and treated with different antibiotic concentrations and with isolated bacteriophages alone or in staggered combinations. A strong biofilm reduction was observed when phages were combined with antibiotic, where combinations with gentamicin showed a better outcome compared to vancomycin. Regarding the resistant strain, daptomycin had a superior antibiofilm effect than fosfomycin.}, } @article {pmid36145447, year = {2022}, author = {Behzadi, P and Gajdács, M and Pallós, P and Ónodi, B and Stájer, A and Matusovits, D and Kárpáti, K and Burián, K and Battah, B and Ferrari, M and Doria, C and Caggiari, G and Khusro, A and Zanetti, S and Donadu, MG}, title = {Relationship between Biofilm-Formation, Phenotypic Virulence Factors and Antibiotic Resistance in Environmental Pseudomonas aeruginosa.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {36145447}, issn = {2076-0817}, abstract = {The formation of a protective biofilm by Pseudomonas aeruginosa (PA) is one of the hallmarks of their survival both in vivo and in harsh environmental conditions, thus, biofilm-eradication has relevance from therapeutic perspectives and for infection control. The aim of our study was to investigate the possible relationship between antibiotic resistance, biofilm-forming capacity and virulence factors in n = 166 PA isolates of environmental origin. Antimicrobial susceptibility testing and the phenotypic detection of resistance determinants were carried out using standard protocols. The biofilm-forming capacity of PA was tested using a standardized crystal violet microtiter plate-based method. Motility (swimming, swarming, and twitching) and siderophore production of the isolates were also assessed. Resistance rates were highest for ciprofloxacin (46.98%), levofloxacin (45.18%), ceftazidime (31.92%) and cefepime (30.12%); 19.28% of isolates met the criteria to be classified as multidrug-resistant (MDR). Efflux pump overexpression, AmpC overexpression, and modified Hodge-test positivity were noted in 28.31%, 18.07% and 3.61%, respectively. 22.89% of isolates were weak/non-biofilm producers, while 27.71% and 49.40% were moderate and strong biofilm producers, respectively. Based on MDR status of the isolates, no significant differences in biofilm-production were shown among environmental PA (non-MDR OD570 [mean ± SD]: 0.416 ± 0.167 vs. MDR OD570: 0.399 ± 0.192; p > 0.05). No significant association was observed between either motility types in the context of drug resistance or biofilm-forming capacity (p > 0.05). 83.13% of isolates tested were positive for siderophore production. The importance of PA as a pathogen in chronic and healthcare-associated infections has been described extensively, while there is increasing awareness of PA as an environmental agent in agriculture and aquaculture. Additional studies in this field would be an important undertaking to understand the interrelated nature of biofilm production and antimicrobial resistance, as these insights may become relevant bases for developing novel therapeutics and eradication strategies against PA.}, } @article {pmid36145393, year = {2022}, author = {Rahman, MA and Sahoo, N and Yemmireddy, V}, title = {Analysis of Sanitizer Rotation on the Susceptibility, Biofilm Forming Ability and Caco-2 Cell Adhesion and Invasion of Listeria.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {36145393}, issn = {2076-0817}, support = {SC2 GM139715/GM/NIGMS NIH HHS/United States ; Startup funds//University of Texas Rio Grande Valley/ ; }, abstract = {The purpose of this study was to determine the effect of sanitizer use conditions on the susceptibility, biofilm forming ability and pathogenicity of Listeria monocytogenes. Two different strains of L. monocytogenes and a non-pathogenic L. innocua were exposed to sodium hypochlorite, benzalkonium chloride and peroxyacetic acid at different concentrations (4 to 512 ppm) and treatment times (30 s to 5 min), respectively. Under the tested conditions, no significant difference (p > 0.05) in reduction was observed among the three tested sanitizers. A reduction of 1 to 8 log CFU/mL was observed depending upon the sanitizer concentration and treatment times. The survived cells at the highest sublethal concentration and treatment time of a particular sanitizer upon re-exposure to the same or different sanitizer showed either no change or increased susceptibility when compared to parent strains. Upon repeated exposure to sanitizers at progressively increasing concentrations from 1 to 128 ppm, L. innocua was able to survive concentrations of up to 32 ppm benzalkonium chloride and 64 ppm peroxyacetic acid treatments, respectively. At the tested sub-lethal concentrations, no significant difference (p > 0.05) in biofilm formation was observed among the tested strains. Caco-2 interaction with L. innocua showed a reduction in invasion ability with sublethal concentrations of sanitizers.}, } @article {pmid36144459, year = {2022}, author = {van der Mee-Marquet, N and Dos Santos, S and Diene, SM and Duflot, I and Mereghetti, L and Valentin, AS and François, P and On Behalf Of The Spiadi Collaborative Group, }, title = {Strong Biofilm Formation and Low Cloxacillin Susceptibility in Biofilm-Growing CC398 Staphylococcus aureus Responsible for Bacteremia in French Intensive Care Units, 2021.}, journal = {Microorganisms}, volume = {10}, number = {9}, pages = {}, pmid = {36144459}, issn = {2076-2607}, abstract = {A prospective 3-month study carried out in 267 ICUs revealed an S. aureus nosocomial bacteremia in one admitted patient out of 110 in adult and pediatric sectors, and in one out of 230 newborns; 242 S. aureus bacteremias occurred during the study, including 7.9% MRSA-bacteremias. In one ICU out of ten, the molecular characteristics, antimicrobial susceptibility profiles and biofilm production of the strains responsible for S. aureus bacteremia were studied. Of the 53 strains studied, 9.4% were MRSA and 52.8% were resistant to erythromycin. MLST showed the predominance of CC398 (37.7% of the strains) followed by CC8 (17.0%), CC45 (13.2%) and CC30 (9.4%). The lukF/S genes were absent from our isolates and tst-1 was found in 9.4% of the strains. Under static conditions and without exposure to glucose, biofilm production was rare (9.4% of the strains, without any CC398). The percentage increased to 62.3% for strains grown in broth supplemented with 1% glucose (including 7 out of 9 CC8 and 17 out of the 20 CC398). Further study of the CC398, including whole genome sequencing, revealed (1) highly frequent patient death within seven days after CC398 bacteremia diagnosis (47.4%), (2) 95.0% of the strains producing biofilm when exposed to sub-inhibitory concentrations of cloxacillin, (3) a stronger biofilm production following exposure to cloxacillin than that observed in broth supplemented with glucose only (p < 0.001), (4) a high minimum biofilm eradication concentration of cloxacillin (128 mg/L) indicating a low cloxacillin susceptibility of biofilm-growing CC398, (5) 95.0% of the strains carrying a ϕSa-3 like prophage and its particular evasion cluster (i.e., yielding chp and scin genes), and (6) 30.0% of the strains carrying a ϕMR11-like prophage and yielding a higher ability to produce biofilm. Our results provide evidence that active surveillance is required to avoid spreading of this virulent staphylococcal clone.}, } @article {pmid36144381, year = {2022}, author = {Shokeen, B and Pham, E and Esfandi, J and Kondo, T and Okawa, H and Nishimura, I and Lux, R}, title = {Effect of Calcium Ion Supplementation on Oral Microbial Composition and Biofilm Formation In Vitro.}, journal = {Microorganisms}, volume = {10}, number = {9}, pages = {}, pmid = {36144381}, issn = {2076-2607}, support = {N/A//SINTX Technologies (United States)/ ; Leading Young Researcher Overseas Visit Program Fellowship//Tohoku University/ ; Research Fellowship for Young Scientists 19J117670//Japan Society for the Promotion of Science/ ; }, abstract = {The oral cavity contains a variety of ecological niches with very different environmental conditions that shape biofilm structure and composition. The space between the periodontal tissue and the tooth surface supports a unique anaerobic microenvironment that is bathed in the nutrient-rich gingival crevicular fluid (GCF). During the development of periodontitis, this environment changes and clinical findings reported a sustained level of calcium ion concentration in the GCF collected from the periodontal pockets of periodontitis patients. Here, we report the effect of calcium ion supplementation on human oral microbial biofilm formation and community composition employing an established SHI medium-based in vitro model system. Saliva-derived human microbial biofilms cultured in calcium-supplemented SHI medium (SHICa) exhibited a significant dose-dependent increase in biomass and metabolic activity. The effect of SHICa medium on the microbial community composition was evaluated by 16S rRNA gene sequencing using saliva-derived microbial biofilms from healthy donors and periodontitis subjects. In this study, intracellular microbial genomic DNA (iDNA) and extracellular DNA (eDNA) were analyzed separately at the genus level. Calcium supplementation of SHI medium had a differential impact on iDNA and eDNA in the biofilms derived from healthy individuals compared to those from periodontitis subjects. In particular, the genus-level composition of the eDNA portion was distinct between the different biofilms. This study demonstrated the effect of calcium in a unique microenvironment on oral microbial complex supporting the dynamic transformation and biofilm formation.}, } @article {pmid36144359, year = {2022}, author = {Henrici De Angelis, L and Stirpe, M and Tomolillo, D and Donelli, G and Francolini, I and Vuotto, C}, title = {The Multifunctional Role of Poloxamer P338 as a Biofilm Disrupter and Antibiotic Enhancer: A Small Step forward against the Big Trouble of Catheter-Associated Escherichia coli Urinary Tract Infections.}, journal = {Microorganisms}, volume = {10}, number = {9}, pages = {}, pmid = {36144359}, issn = {2076-2607}, support = {RP11715C785E4434//Sapienza University of Rome/ ; }, abstract = {Poloxamer 338 (P338), a nonionic surfactant amphiphilic copolymer, is herein proposed as an anti-biofilm compound for the management of catheter-associated urinary tract infections (CAUTIs). P338's ability to disrupt Escherichia coli biofilms on silicone urinary catheters and to serve as antibiotic enhancer was evaluated for biofilm-producing E. coli Ec5FSL and Ec9FSL clinical strains, isolated from urinary catheters. In static conditions, quantitative biofilm formation assay allowed us to determine the active P338 concentration. In dynamic conditions, the BioFlux system, combined with confocal laser scanning microscopy, allowed us to investigate the P338 solution's ability to detach biofilm, alone or in combination with sub-MIC concentrations of cefoxitin (FOX). The 0.5% P338 solution was able to destroy the structure of E. coli biofilms, to reduce the volume and area fraction covered by adherent cells (41.42 ± 4.79% and 56.20 ± 9.22% reduction for the Ec5FSL and Ec9FSL biofilms, respectively), and to potentiate the activity of 1\2 MIC FOX in disaggregating biofilms (19.41 ± 7.41% and 34.66 ± 3.75% reduction in the area fraction covered by biofilm for Ec5FSL and Ec9FSL, respectively) and killing cells (36.85 ± 7.13% and 32.33 ± 4.65% increase in the biofilm area covered by dead Ec5FSL and Ec9FSL cells, respectively).}, } @article {pmid36144331, year = {2022}, author = {Tan, HC and Cheung, GSP and Chang, JWW and Zhang, C and Lee, AHC}, title = {Enterococcus faecalis Shields Porphyromonas gingivalis in Dual-Species Biofilm in Oxic Condition.}, journal = {Microorganisms}, volume = {10}, number = {9}, pages = {}, pmid = {36144331}, issn = {2076-2607}, abstract = {Aim: To develop a reproducible biofilm model consisting of Enterococcus faecalis (E. faecalis) and Porphyromonas gingivalis (P. gingivalis) and to evaluate the interaction between the two bacterial species. Methodology: E. faecalis and P. gingivalis were grown in mono-culture, sequential, and co-culture models for 96 h in a 96-well polystyrene microtiter plate under both aerobic and anaerobic conditions separately. The viability of the two bacterial species in the biofilms was quantified by polymerase chain reaction (qPCR). Biofilm thickness and protein contents were measured using confocal laser scanning microscopy (CLSM). Two-way analysis of variance (ANOVA) was performed to analyze cell viability and biofilm thickness among different culture models cultivated under either aerobic or anaerobic conditions. The level of significance was set at p < 0.05. Results: Different culture models tested did not show any significant difference between the viable cell counts of both E. faecalis and P. gingivalis cultivated under aerobic and anaerobic conditions (p > 0.05). Biofilm was significantly thicker (p < 0.05) in the co-culture models compared to the mono-culture and sequential models. Protein contents in the biofilms were more pronounced when both bacterial species were co-cultured under aerobic conditions. Conclusions: E. faecalis appeared to shield P. gingivalis and support its continued growth in oxic (aerobic) conditions. The co-culture model of E. faecalis and P. gingivalis produced a significantly thicker biofilm irrespective of the presence or absence of oxygen, while increased protein contents were only observed in the presence of oxygen.}, } @article {pmid36144293, year = {2022}, author = {Gumber, HK and Louyakis, AS and Sarma, T and Fabijanic, KI and Paul, R and Mellenbruch, K and Kilpatrick-Liverman, L}, title = {Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties.}, journal = {Microorganisms}, volume = {10}, number = {9}, pages = {}, pmid = {36144293}, issn = {2076-2607}, support = {NA//Colgate-Palmolive (United States)/ ; }, abstract = {An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF2)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm's architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF2 dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF2. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF2 toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.}, } @article {pmid36143678, year = {2022}, author = {Grzegorczyk, M and Pogorzelski, S and Janowicz, P and Boniewicz-Szmyt, K and Rochowski, P}, title = {Micron-Scale Biogeography of Seawater Biofilm Colonies at Submersed Solid Substrata Affected by Organic Matter and Microbiome Transformation in the Baltic Sea.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {18}, pages = {}, pmid = {36143678}, issn = {1996-1944}, abstract = {The aim of this research was to determine temporal and spatial evolution of biofilm architecture formed at model solid substrata submersed in Baltic sea coastal waters in relation to organic matter transformation along a one-year period. Several materials (metals, glass, plastics) were deployed for a certain time, and the collected biofilm-covered samples were studied with a confocal microscopy technique using the advanced programs of image analysis. The geometric and structural biofilm characteristics: biovolume, coverage fraction, mean thickness, spatial heterogeneity, roughness, aggregation coefficient, etc., turned out to evolve in relation to organic matter transformation trends, trophic water status, microbiome evolution, and biofilm micro-colony transition from the heterotrophic community (mostly bacteria) to autotrophic (diatom-dominated) systems. The biofilm morphology parameters allowed the substratum roughness, surface wettability, chromatic organisms colony adaptation to substrata, and quorum sensing or cell to cell signaling effects to be quantitatively evaluated. In addition to the previous work, the structural biofilm parameters could become further novel trophic state indicators.}, } @article {pmid36142675, year = {2022}, author = {Pouget, C and Dunyach-Remy, C and Magnan, C and Pantel, A and Sotto, A and Lavigne, JP}, title = {Polymicrobial Biofilm Organization of Staphylococcus aureus and Pseudomonas aeruginosa in a Chronic Wound Environment.}, journal = {International journal of molecular sciences}, volume = {23}, number = {18}, pages = {}, pmid = {36142675}, issn = {1422-0067}, support = {Thematique Phare 1//Centre Hospitalier Universitaire de Nîmes/ ; }, mesh = {Biofilms ; Humans ; *Pseudomonas aeruginosa ; *Staphylococcal Infections ; Staphylococcus aureus ; Wound Healing ; }, abstract = {Biofilm on the skin surface of chronic wounds is an important step that involves difficulties in wound healing. The polymicrobial nature inside this pathogenic biofilm is key to understanding the chronicity of the lesion. Few in vitro models have been developed to study bacterial interactions inside this chronic wound. We evaluated the biofilm formation and the evolution of bacteria released from this biofilm on the two main bacteria isolated in this condition, Staphylococcus aureus and Pseudomonas aeruginosa, using a dynamic system (BioFlux™ 200) and a chronic wound-like medium (CWM) that mimics the chronic wound environment. We observed that all species constituted a faster biofilm in the CWM compared to a traditional culture medium (p < 0.01). The percentages of biofilm formation were significantly higher in the mixed biofilm compared to those determined for the bacterial species alone (p < 0.01). Biofilm organization was a non-random structure where S. aureus aggregates were located close to the wound surface, whereas P. aeruginosa was located deeper in the wound bed. Planktonic biofilm-detached bacteria showed decreased growth, overexpression of genes encoding biofilm formation, and an increase in the mature biofilm biomass formed. Our data confirmed the impact of the chronic wound environment on biofilm formation and on bacterial lifecycle inside the biofilm.}, } @article {pmid36142597, year = {2022}, author = {Kim, S and Lee, JH and Kim, YG and Tan, Y and Lee, J}, title = {Hydroquinones Inhibit Biofilm Formation and Virulence Factor Production in Staphylococcus aureus.}, journal = {International journal of molecular sciences}, volume = {23}, number = {18}, pages = {}, pmid = {36142597}, issn = {1422-0067}, support = {2021R1I1A3A04037486//The National Research Foundation of Korea (NRF)/ ; 2021R1A2C1008368//The National Research Foundation of Korea (NRF)/ ; 2014R1A6A1031189//The National Research Foundation of Korea (NRF)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Exotoxins/pharmacology ; Humans ; Hydroquinones/pharmacology ; Lipase ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections ; Staphylococcus aureus ; Virulence Factors/pharmacology ; }, abstract = {Staphylococcus aureus is one of the major pathogens responsible for antimicrobial resistance-associated death. S. aureus can secrete various exotoxins, and staphylococcal biofilms play critical roles in antibiotic tolerance and the persistence of chronic infections. Here, we investigated the inhibitory effects of 18 hydroquinones on biofilm formation and virulence factor production by S. aureus. It was found that 2,5-bis(1,1,3,3-tetramethylbutyl) hydroquinone (TBHQ) at 1 µg/mL efficiently inhibits biofilm formation by two methicillin-sensitive and two methicillin-resistant S. aureus strains with MICs of 5 µg/mL, whereas the backbone compound hydroquinone did not (MIC > 400 µg/mL). In addition, 2,3-dimethylhydroquinone and tert-butylhydroquinone at 50 µg/mL also exhibited antibiofilm activity. TBHQ at 1 µg/mL significantly decreased the hemolytic effect and lipase production by S. aureus, and at 5−50 µg/mL was non-toxic to the nematode Caenorhabditis elegans and did not adversely affect Brassica rapa seed germination or growth. Transcriptional analyses showed that TBHQ suppressed the expression of RNAIII (effector of quorum sensing). These results suggest that hydroquinones, particularly TBHQ, are potentially useful for inhibiting S. aureus biofilm formation and virulence.}, } @article {pmid36142185, year = {2022}, author = {Klagisa, R and Racenis, K and Broks, R and Balode, AO and Kise, L and Kroica, J}, title = {Analysis of Microorganism Colonization, Biofilm Production, and Antibacterial Susceptibility in Recurrent Tonsillitis and Peritonsillar Abscess Patients.}, journal = {International journal of molecular sciences}, volume = {23}, number = {18}, pages = {}, pmid = {36142185}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; *Peritonsillar Abscess/diagnosis/drug therapy/microbiology ; Prospective Studies ; Staphylococcus aureus ; *Tonsillitis/complications/drug therapy ; }, abstract = {Background: Despite the widespread use of antibiotics to treat infected tonsils, episodes of tonsillitis tend to recur and turn into recurrent tonsillitis (RT) or are complicated by peritonsillar abscesses (PTAs). The treatment of RT and PTAs remains surgical, and tonsillectomies are still relevant. Materials and methods: In a prospective, controlled study, we analyzed the bacteria of the tonsillar crypts of 99 patients with RT and 29 patients with a PTA. We performed the biofilm formation and antibacterial susceptibility testing of strains isolated from study patients. We compared the results obtained between patient groups with the aim to identify any differences that may contribute to ongoing symptoms of RT or that may play a role in developing PTAs. Results: The greatest diversity of microorganisms was found in patients with RT. Gram-positive bacteria were predominant in both groups. Candida species were predominant in patients with a PTA (48.3% of cases). Irrespective of patient group, the most commonly isolated pathogenic bacterium was S. aureus (in 33.3% of RT cases and in 24.14% of PTA cases). The most prevalent Gram-negative bacterium was K. pneumoniae (in 10.1% of RT cases and in 13.4% of PTA cases). At least one biofilm-producing strain was found in 37.4% of RT cases and in 27.6% of PTA cases. Moderate or strong biofilm producers were detected in 16 out of 37 cases of RT and in 2 out of 8 PTA cases. There was a statistically significant association found between the presence of Gram-positive bacteria and a biofilm-formation phenotype in the RT group and PTA group (Pearson χ2 test, p < 0.001). S. aureus and K. pneumoniae strains were sensitive to commonly used antibiotics. One S. aureus isolate was identified as MRSA. Conclusions: S. aureus is the most common pathogen isolated from patients with RT, and Candida spp. are the most common pathogens isolated from patients with a PTA. S. aureus isolates are susceptible to most antibiotics. Patients with RT more commonly have biofilm-producing strains, but patients with a PTA more commonly have biofilm non-producer strains. K. pneumoniae does not play a major role in biofilm production.}, } @article {pmid36141000, year = {2022}, author = {Masebe, RD and Thantsha, MS}, title = {Anti-Biofilm Activity of Cell Free Supernatants of Selected Lactic Acid Bacteria against Listeria monocytogenes Isolated from Avocado and Cucumber Fruits, and from an Avocado Processing Plant.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {18}, pages = {}, pmid = {36141000}, issn = {2304-8158}, support = {118531//National Research Foundation/ ; Not Applicable//University of Pretoria/ ; }, abstract = {Listeria monocytogenes forms biofilms on food contact surfaces, a niche from where it dislodges to contaminate food products including fresh produce. Probiotics and their derivatives are considered promising alternative strategies to curb the presence of L. monocytogenes in varied food applications. Nonetheless, studies on their anti-biofilm effects against L. monocytogenes from avocados and cucumbers are sparse. This study screened the biofilm formation capabilities of L. monocytogenes strains Avo and Cuc isolated from the avocado and cucumber fruits respectively, and strain 243 isolated from an avocado processing plant; and evaluated the anti-biofilm effects of cell free supernatants (CFS) of Lactobacillus acidophilus La14 150B, Lactiplantibacillus plantarum B411 and Lacticaseibacillus rhamnosus ATCC 53103 against their biofilms formed on polyvinyl chloride (PVC) and stainless steel. All the L. monocytogenes strains formed biofilms (classified either as moderate or strong biofilm formers) on these materials. The presence of CFS reduced the biofilm formation capabilities of these strains and disrupted the integrity of their pre-formed biofilms. Quantitative reverse transcriptase polymerase chain reaction revealed significant reduction of positive regulatory factor A (prfA) gene expression by L. monocytogenes biofilm cells in the presence of CFS (p < 0.05). Thus, these CFS have potential as food grade sanitizers for control of L. monocytogenes biofilms in the avocado and cucumber processing facilities.}, } @article {pmid36140855, year = {2022}, author = {Ejaz, H and Junaid, K and Yasmeen, H and Naseer, A and Alam, H and Younas, S and Qamar, MU and Abdalla, AE and Abosalif, KOA and Ahmad, N and Bukhari, SNA}, title = {Multiple Antimicrobial Resistance and Heavy Metal Tolerance of Biofilm-Producing Bacteria Isolated from Dairy and Non-Dairy Food Products.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {18}, pages = {}, pmid = {36140855}, issn = {2304-8158}, support = {DSR2022-RG-0154//Deanship of Scientific Research at Jouf University/ ; }, abstract = {Foodborne pathogens have acquired the ability to produce biofilms to survive in hostile environments. This study evaluated biofilm formation, antimicrobial resistance (AMR), and heavy metal tolerance of bacteria isolated from dairy and non-dairy food products. We aseptically collected and processed 200 dairy and non-dairy food specimens in peptone broth, incubated them overnight at 37 °C, and sub-cultured them on various culture media. Bacterial growth was identified with biochemical tests and API 20E and 20NE strips. The AMR of the isolates was observed against different antibacterial drug classes. Biofilm formation was detected with the crystal violet tube method. Heavy metal salts were used at concentrations of 250−1500 µg/100 mL to observe heavy metal tolerance. We isolated 180 (50.4%) bacteria from dairy and 177 (49.6%) from non-dairy food samples. The average colony-forming unit (CFU) count for dairy and non-dairy samples was 2.9 ± 0.9 log CFU/mL and 5.1 ± 0.3 log CFU/mL, respectively. Corynebacterium kutscheri (n = 74), lactobacilli (n = 73), and Staphylococcus aureus (n = 56) were the predominant Gram-positive and Shigella (n = 10) the predominant Gram-negative bacteria isolated. The correlation between biofilm formation and AMR was significant (p < 0.05) for most cephalosporins, aminoglycosides, and fluoroquinolones. Heavy metal tolerance tended to be higher in biofilm producers at different metal concentrations. The pathogens isolated from dairy and non-dairy food showed a high burden of AMR, high propensity for biofilm formation, and heavy metal tolerance, and pose an imminent threat to public health.}, } @article {pmid36140163, year = {2022}, author = {Thomsen, K and Høiby, N and Jensen, PØ and Ciofu, O and Moser, C}, title = {Immune Response to Biofilm Growing Pulmonary Pseudomonas aeruginosa Infection.}, journal = {Biomedicines}, volume = {10}, number = {9}, pages = {}, pmid = {36140163}, issn = {2227-9059}, support = {NNF17OC0025074//Novo Nordisk Foundation/ ; }, abstract = {Biofilm infections are tolerant to the host responses and recalcitrance to antibiotic drugs and disinfectants. The induced host-specific innate and adaptive immune responses by established biofilms are significantly implicated and contributes to the course of the infections. Essentially, the host response may be the single one factor impacting the outcome most, especially in cases where the biofilm is caused by low virulent opportunistic bacterial species. Due to the chronicity of biofilm infections, activation of the adaptive immune response mechanisms is frequently experienced, and instead of clearing the infection, the adaptive response adds to the pathogenesis. To a high degree, this has been reported for chronic Pseudomonas aeruginosa lung infections, where both a pronounced antibody response and a skewed Th1/Th2 balance has been related to a poorer outcome. In addition, detection of an adaptive immune response can be used as a significant indicator of a chronic P. aeruginosa lung infection and is included in the clinical definitions as such. Those issues are presented in the present review, along with a characterization of the airway structure in relation to immune responses towards P. aeruginosa pulmonary infections.}, } @article {pmid36140002, year = {2022}, author = {Jubair, N and R, M and Fatima, A and Mahdi, YK and Abdullah, NH}, title = {Evaluation of Catechin Synergistic and Antibacterial Efficacy on Biofilm Formation and acrA Gene Expression of Uropathogenic E. coli Clinical Isolates.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {36140002}, issn = {2079-6382}, abstract = {Uropathogenic Escherichia coli has a propensity to build biofilms to resist host defense and antimicrobials. Recurrent urinary tract infection (UTI) caused by multidrug-resistant, biofilm-forming E. coli is a significant public health problem. Consequently, searching for alternative medications has become essential. This study was undertaken to investigate the antibacterial, synergistic, and antibiofilm activities of catechin isolated from Canarium patentinervium Miq. against three E. coli ATCC reference strains (ATCC 25922, ATCC 8739, and ATCC 43895) and fifteen clinical isolates collected from UTI patients in Baghdad, Iraq. In addition, the expression of the biofilm-related gene, acrA, was evaluated with and without catechin treatment. Molecular docking was performed to evaluate the binding mode between catechin and the target protein using Autodock Vina 1.2.0 software. Catechin demonstrated significant bactericidal activity with a minimum inhibitory concentration (MIC) range of 1-2 mg/mL and a minimum bactericidal concentration (MBC) range of 2-4 mg/mL and strong synergy when combined with tetracycline at the MBC value. In addition, catechin substantially reduced E. coli biofilm by downregulating the acrA gene with a reduction percent ≥ 60%. In silico analysis revealed that catechin bound with high affinity (∆G = -8.2 kcal/mol) to AcrB protein (PDB-ID: 5ENT), one of the key AcrAB-TolC efflux pump proteins suggesting that catechin might inhibit the acrA gene indirectly by docking at the active site of AcrB protein.}, } @article {pmid36139953, year = {2022}, author = {Kunz Coyne, AJ and Stamper, K and Kebriaei, R and Holger, DJ and El Ghali, A and Morrisette, T and Biswas, B and Wilson, M and Deschenes, MV and Canfield, GS and Duerkop, BA and Arias, CA and Rybak, MJ}, title = {Phage Cocktails with Daptomycin and Ampicillin Eradicates Biofilm-Embedded Multidrug-Resistant Enterococcus faecium with Preserved Phage Susceptibility.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {36139953}, issn = {2079-6382}, support = {K24 AI121296/AI/NIAID NIH HHS/United States ; P01 AI152999/AI/NIAID NIH HHS/United States ; R00 AI072961/AI/NIAID NIH HHS/United States ; R01 AI148342/AI/NIAID NIH HHS/United States ; }, abstract = {Multidrug-resistant (MDR) Enterococcus faecium is a challenging nosocomial pathogen known to colonize medical device surfaces and form biofilms. Bacterio (phages) may constitute an emerging anti-infective option for refractory, biofilm-mediated infections. This study evaluates eight MDR E. faecium strains for biofilm production and phage susceptibility against nine phages. Two E. faecium strains isolated from patients with bacteremia and identified to be biofilm producers, R497 (daptomycin (DAP)-resistant) and HOU503 (DAP-susceptible dose-dependent (SDD), in addition to four phages with the broadest host ranges (ATCC 113, NV-497, NV-503-01, NV-503-02) were selected for further experiments. Preliminary phage-antibiotic screening was performed with modified checkerboard minimum biofilm inhibitory concentration (MBIC) assays to efficiently screen for bacterial killing and phage-antibiotic synergy (PAS). Data were compared by one-way ANOVA and Tukey (HSD) tests. Time kill analyses (TKA) were performed against R497 and HOU503 with DAP at 0.5× MBIC, ampicillin (AMP) at free peak = 72 µg/mL, and phage at a multiplicity of infection (MOI) of 0.01. In 24 h TKA against R497, phage-antibiotic combinations (PAC) with DAP, AMP, or DAP + AMP combined with 3- or 4-phage cocktails demonstrated significant killing compared to the most effective double combination (ANOVA range of mean differences 2.998 to 3.102 log10 colony forming units (CFU)/mL; p = 0.011, 2.548 to 2.868 log10 colony forming units (CFU)/mL; p = 0.023, and 2.006 to 2.329 log10 colony forming units (CFU)/mL; p = 0.039, respectively), with preserved phage susceptibility identified in regimens with 3-phage cocktails containing NV-497 and the 4-phage cocktail. Against HOU503, AMP combined with any 3- or 4-phage cocktail and DAP + AMP combined with the 3-phage cocktail ATCC 113 + NV-497 + NV-503-01 demonstrated significant PAS and bactericidal activity (ANOVA range of mean differences 2.251 to 2.466 log10 colony forming units (CFU)/mL; p = 0.044 and 2.119 to 2.350 log10 colony forming units (CFU)/mL; p = 0.028, respectively), however, only PAC with DAP + AMP maintained phage susceptibility at the end of 24 h TKA. R497 and HOU503 exposure to DAP, AMP, or DAP + AMP in the presence of single phage or phage cocktail resulted in antibiotic resistance stabilization (i.e., no antibiotic MBIC elevation compared to baseline) without identified antibiotic MBIC reversion (i.e., lowering of antibiotic MBIC compared to baseline in DAP-resistant and DAP-SDD isolates) at the end of 24 h TKA. In conclusion, against DAP-resistant R497 and DAP-SDD HOU503 E. faecium clinical blood isolates, the use of DAP + AMP combined with 3- and 4-phage cocktails effectively eradicated biofilm-embedded MDR E. faecium without altering antibiotic MBIC or phage susceptibility compared to baseline.}, } @article {pmid36139807, year = {2022}, author = {Roy, PK and Song, MG and Park, SY}, title = {The Inhibitory Effect of Quercetin on Biofilm Formation of Listeria monocytogenes Mixed Culture and Repression of Virulence.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {36139807}, issn = {2076-3921}, support = {2021R1I1A3A04037468//National Research Foundation of Korea/ ; }, abstract = {Listeria monocytogenes is the species of foodborne pathogenic bacteria that causes the infection listeriosis. The food production chain employs various methods to control biofilms, although none are completely successful. This study evaluates the effectiveness of quercetin as a food additive in reducing L. monocytogenes mixed cultures (ATCC19113, ATCC19117, and ATCC15313) biofilm formation on stainless steel (SS), silicon rubber (SR), and hand glove (HG) coupons, as well as tests its antimicrobial activities. With a minimum inhibitory concentration (MIC) of 250 µg/mL, the tested quercetin exhibited the lowest bactericidal action with no visible bacterial growth. In contrast, during various experiments in this work, the inhibitory efficacy of quercetin at sub-MICs levels (1/2, 1/4, and 1/8 MIC) against L. monocytogenes was examined. A control group was not added with quercetin. The current study also investigates the effect of quercetin on the expression of different genes engaged in motility (flaA, fbp), QS (agrA), and virulence (hlyA, prfA). Through increasing quercetin concentration, swarming and swimming motility, biofilm formation, and expression levels of target genes linked to flagella motility, virulence, and quorum-sensing were all dramatically reduced. Quercetin (0−125 μg/mL) was investigated on the SS, SR, and HG surfaces; the inhibitory effects were 0.39−2.07, 0.09−1.96 and 0.03−1.69 log CFU/cm2, respectively (p < 0.05). Field-emission scanning electron microscopy (FE-SEM) corroborated the findings because quercetin prevented the development of biofilms by severing cell-to-cell contacts and inducing cell lysis, which resulted in the loss of normal cell shape. Our findings suggest that plant-derived quercetin should be used as an antimicrobial agent in the food industry to control the development of L. monocytogenes biofilms. These outcomes suggest that bacterial targets are of interest for biofilm reduction, with alternative natural food agents in the food sector along the entire food production chain.}, } @article {pmid36138822, year = {2022}, author = {Dolma, KG and Khati, R and Paul, AK and Rahmatullah, M and de Lourdes Pereira, M and Wilairatana, P and Khandelwal, B and Gupta, C and Gautam, D and Gupta, M and Goyal, RK and Wiart, C and Nissapatorn, V}, title = {Virulence Characteristics and Emerging Therapies for Biofilm-Forming Acinetobacter baumannii: A Review.}, journal = {Biology}, volume = {11}, number = {9}, pages = {}, pmid = {36138822}, issn = {2079-7737}, abstract = {Acinetobacter species is one of the most prevailing nosocomial pathogens with a potent ability to develop antimicrobial resistance. It commonly causes infections where there is a prolonged utilization of medical devices such as CSF shunts, catheters, endotracheal tubes, and similar. There are several strains of Acinetobacter (A) species (spp), among which the majority are pathogenic to humans, but A. baumannii are entirely resistant to several clinically available antibiotics. The crucial mechanism that renders them a multidrug-resistant strain is their potent ability to synthesize biofilms. Biofilms provide ample opportunity for the microorganisms to withstand the harsh environment and further cause chronic infections. Several studies have enumerated multiple physiological and virulence factors responsible for the production and maintenance of biofilms. To further enhance our understanding of this pathogen, in this review, we discuss its taxonomy, pathogenesis, current treatment options, global resistance rates, mechanisms of its resistance against various groups of antimicrobials, and future therapeutics.}, } @article {pmid36137981, year = {2022}, author = {Bullard, S and Mona, M and Pereira, AC and Kajfasz, J and Lemos, JA and Abranches, J and Wallet, SM and Pileggi, R}, title = {Quantitative Analysis of Biofilm Removal Following Instrumentation with TRUShape and Vortex Blue File Systems: Microbiological Study.}, journal = {Frontiers in bioscience (Scholar edition)}, volume = {14}, number = {3}, pages = {18}, doi = {10.31083/j.fbs1403018}, pmid = {36137981}, issn = {1945-0524}, mesh = {*Biofilms ; *Dental Pulp Cavity/microbiology ; *Enterococcus faecalis ; Humans ; Molar ; Polymethyl Methacrylate ; *Root Canal Preparation ; }, abstract = {Mesial roots and isthmuses of mandibular molars are difficult areas to obtain adequate disinfection of root canal walls, and consequently microorganisms can survive treatment. The present study compared, through real-time polymerase chain reaction (qPCR), the effectiveness of TRUShape (TS) (Dentsply Tulsa Dental Specialties, Tulsa, OK) and Vortex Blue (VB) (Dentsply Tulsa Dental Specialties, Tulsa, OK) in removing Enterococcus faecalis (E. faecalis) from the mesial canals and isthmuses of mandibular molars. Fifty extracted human lower molars were inoculated with E. faecalis OG1RF for 14 days, and then an initial bacterial sample was collected with paper points from mesiobuccal and mesiolingual canals and isthmuses. The specimens were randomly divided into four groups (n = 10 teeth; 20 canals each), according to instrumentation system: TS 25/0.06, TS 30/0.06, VB 25/0.06 and VB 30/0.06. The remaining 10 teeth were divided between positive control, inoculated teeth without instrumentation or irrigation, and negative controls, teeth without inoculation. After instrumentation, the final sample was taken using paper points and DNA was isolated. Primers specific for E. faecalis were used for qPCR. The bacterial reduction between pre- and post-instrumentation was calculated. One-way analysis of variance (ANOVA) with Bonferroni's multiple-comparisons tests were for statistical analysis with significance of (p < 0.05). All file systems were able to reduce the load of E. faecalis from the prepared root canals, however, TS size 30 removed significantly more bacteria than size 25. Interestingly, regardless of the size, TS files removed significantly more E. faecalis biofilm (p < 0.05) than did VB files (63.7% vs 50.8% for size 25, and 69.5% vs 56% for size 30). In conclusion, when combined with irrigation, TS file system is more effective than VB in reducing E. faecalis biofilms from mesiobuccal and mesiolingual canals and the isthmuses of mandibular molars.}, } @article {pmid36136646, year = {2022}, author = {Dzib-Baak, HE and Uc-Cachón, AH and Dzul-Beh, AJ and Rosado-Manzano, RF and Gracida-Osorno, C and Molina-Salinas, GM}, title = {Efficacy of Fosfomycin against Planktonic and Biofilm-Associated MDR Uropathogenic Escherichia coli Clinical Isolates.}, journal = {Tropical medicine and infectious disease}, volume = {7}, number = {9}, pages = {}, pmid = {36136646}, issn = {2414-6366}, abstract = {Urinary tract infections (UTI) are a severe public health problem and are caused mainly by the uropathogenic Escherichia coli (UPEC). Antimicrobial resistance and limited development of new antimicrobials have led to the reuse of old antibiotics such as fosfomycin. The aim of this study was to evaluate the in vitro efficacy of fosfomycin on a collection of multidrug-resistant (MDR) UPEC and the degradative activity on biofilm producers. A total of 100 MDR UPEC clinical isolates were collected from patients at Mexican second- and third-level hospitals. Microorganism identification was performed using an automated system, the evaluation of the susceptibility of clinical isolates to fosfomycin was performed using the resazurin microtiter assay, and the identification of biofilm producers and the effect of fosfomycin in biofilms were evaluated using the crystal violet method. Among planktonic MDR UPEC, 93% were susceptible to fosfomycin. Eighty-three MDR UPEC were categorized as weak (39.8%), moderate (45.2%), and strong (14.5%) biofilm producers. Fosfomycin exhibited degradative activity ranging from 164.4 µg/mL to 1045 µg/mL. Weak producers required statistically lower concentrations of fosfomycin to destroy the biofilm, contrary to moderate and strong producers. In conclusion, fosfomycin could be an option for the treatment of infections caused by MDR UPEC, for which the antimicrobial treatment is more often becoming limited.}, } @article {pmid36136259, year = {2022}, author = {Madan, R and Madan, S and Hussain, A}, title = {Kinetic Study for Startup of Aerobic Moving Bed Biofilm Reactor in Treatment of Textile Dye Wastewater.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {36136259}, issn = {1559-0291}, abstract = {Due to high augmentation in population and low availability of land, the quantum of wastewater production has surged resulting in advancements in wastewater treatment systems. To cope under such stressful circumstances, moving bed biofilm reactor (MBBR) proves to be an upgraded treatment technology for industrial and municipal wastewater treatment. The present startup study has been carried out using a laboratory-scale aerobic MBBR with working volume of 25L for textile dye wastewater treatment having AnoxKaldnes K3 media at filling percentage of 50%. In order to acclimatize the microorganisms on textile dye wastewater, the startup of the reactor was carried out using lactose as readily degradable co-substrate with textile dye wastewater in different ratios at hydraulic retention time (HRT) of 24 h. The biofilm on the media was developed in 63 days duration and the reactor attained pseudo-steady state (PSS) in 185 days period. During PSS condition of the MBBR, the maximum chemical oxygen demand (COD) removal efficiency of 92% with mixed liquor suspended solids (MLSS) concentration of 4224 ± 22 mg/L has been achieved. The kinetic study for biodegradation of textile dye wastewater has also been carried out using the Monod growth kinetics. The values of bio-kinetic coefficients of yield of heterotrophic biomass (Y) and endogenous decay coefficient for heterotrophic biomass (Kd) recorded are 0.394 mgVSS/mgCOD.d and 0.087 day[-1], respectively. The values of specific substrate removal rate (k), Monod half saturation constant (Ks), and maximum specific growth rate for heterotrophic biomass (µmax) are 0.024 mgCOD/mgVSS.d, 53.203 mg/L, and 0.0095 day[-1], respectively, demonstrating the suitability and healthy performance of MBBR for textile dye wastewater treatment.}, } @article {pmid36135688, year = {2022}, author = {Sousa, IS and Mello, TP and Pereira, EP and Granato, MQ and Alviano, CS and Santos, ALS and Kneipp, LF}, title = {Biofilm Formation by Chromoblastomycosis Fungi Fonsecaea pedrosoi and Phialophora verrucosa: Involvement with Antifungal Resistance.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {9}, pages = {}, pmid = {36135688}, issn = {2309-608X}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 142547/2018-3//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Fundação de Amparo à Pesquisa no Estado do Rio de Janeiro/ ; //Fundação Oswaldo Cruz/ ; }, abstract = {Patients with chromoblastomycosis (CBM) suffer chronic tissue lesions that are hard to treat. Considering that biofilm is the main growth lifestyle of several pathogens and it is involved with both virulence and resistance to antimicrobial drugs, we have investigated the ability of CBM fungi to produce this complex, organized and multicellular structure. Fonsecaea pedrosoi and Phialophora verrucosa conidial cells were able to adhere on a polystyrene abiotic substrate, differentiate into hyphae and produce a robust viable biomass containing extracellular matrix. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) showed the tridimensional architecture of the mature biofilms, revealing a dense network of interconnected hyphae, inner channels and amorphous extracellular polymeric material. Interestingly, the co-culture of each fungus with THP-1 macrophage cells, used as a biotic substrate, induced the formation of a mycelial trap covering and damaging the macrophages. In addition, the biofilm-forming cells of F. pedrosoi and P. verrucosa were more resistant to the conventional antifungal drugs than the planktonic-growing conidial cells. The efflux pump activities of P. verrucosa and F. pedrosoi biofilms were significantly higher than those measured in conidia. Taken together, the data pointed out the biofilm formation by CBM fungi and brought up a discussion of the relevance of studies about their antifungal resistance mechanisms.}, } @article {pmid36135626, year = {2022}, author = {Park, J and Kim, H and Kang, HK and Choi, MC and Park, Y}, title = {Lycosin-II Exhibits Antifungal Activity and Inhibits Dual-Species Biofilm by Candida albicans and Staphylococcus aureus.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {9}, pages = {}, pmid = {36135626}, issn = {2309-608X}, support = {NRF-2017M3A9E4077206 and NRF-2021R1C1C2009855//National Research Foundation of Korea/ ; MSIT; No. 2017-0-01714//Institute for Information and Communications Technology Promotion/ ; }, abstract = {The increase and dissemination of antimicrobial resistance is a global public health issue. To address this, new antimicrobial agents have been developed. Antimicrobial peptides (AMPs) exhibit a wide range of antimicrobial activities against pathogens, including bacteria and fungi. Lycosin-II, isolated from the venom of the spider Lycosa singoriensis, has shown antibacterial activity by disrupting membranes. However, the mode of action of Lycosin-II and its antifungal activity have not been clearly described. Therefore, we confirmed that Lycosin-II showed antifungal activity against Candida albicans (C. albicans). To investigate the mode of action, membrane-related assays were performed, including an evaluation of C. albicans membrane depolarization and membrane integrity after exposure to Lycosin-II. Our results indicated that Lycosin-II damaged the C. albicans membrane. Additionally, Lycosin-II induced oxidative stress through the generation of reactive oxygen species (ROS) in C. albicans. Moreover, Lycosin-II exhibited an inhibitory effect on dual-species biofilm formation by C. albicans and Staphylococcus aureus (S. aureus), which are the most co-isolated fungi and bacteria. These results revealed that Lycosin-II can be utilized against C. albicans and dual-species strain infections.}, } @article {pmid36135007, year = {2022}, author = {Tahir, S and Emanuel, S and Inglis, DW and Vickery, K and Deva, AK and Hu, H}, title = {Mild Positive Pressure Improves the Efficacy of Benzalkonium Chloride against Staphylococcus aureus Biofilm.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {36135007}, issn = {2306-5354}, abstract = {Current protocols using liquid disinfectants to disinfect heat-sensitive hospital items frequently fail, as evidenced by the continued isolation of bacteria following decontamination. The contamination is, in part, due to biofilm formation. We hypothesize that mild positive pressure (PP) will disrupt this biofilm structure and improve liquid disinfectant/detergent penetration to biofilm bacteria for improved killing. Staphylococcus aureus biofilm, grown on polycarbonate coupons in the biofilm reactor under shear at 35 °C for 3 days, was treated for 10 min and 60 min with various dilutions of benzalkonium chloride without PP at 1 atmosphere (atm), and with PP at 3, 5, 7, and 10 atm. The effect on biofilm and residual bacterial viability was determined by standard plate counts, confocal laser scanning microscopy, and scanning electron microscopy. Combined use of benzalkonium chloride and PP up to 10 atm significantly increased biofilm killing up to 4.27 logs, as compared to the treatment using disinfectant alone. Microscopy results were consistent with the viability plate count results. PP improved disinfectant efficacy against bacterial biofilm. The use of mild PP is possible in many flow situations or if equipment/contaminated surfaces can be placed in a pressure chamber.}, } @article {pmid36131351, year = {2022}, author = {Maharjan, S and Ansari, M and Maharjan, P and Rai, KR and Sabina, KC and Kattel, HP and Rai, G and Rai, SK}, title = {Phenotypic detection of methicillin resistance, biofilm production, and inducible clindamycin resistance in Staphylococcus aureus clinical isolates in Kathmandu, Nepal.}, journal = {Tropical medicine and health}, volume = {50}, number = {1}, pages = {71}, pmid = {36131351}, issn = {1348-8945}, abstract = {INTRODUCTION: Methicillin resistance, inducible clindamycin resistance (ICR), biofilm production, and increased minimum inhibitory concentration (MIC) of vancomycin in Staphylococcus aureus are major causes of antibiotic treatment failure and increased morbidity and mortality. The surveillance of such isolates and the study of their antimicrobial pattern are essential in managing the infections caused by these isolates. This study aimed to determine methicillin resistance, biofilm production, and ICR in S. aureus isolates from a tertiary care hospital in Kathmandu, Nepal.

MATERIALS AND METHODS: A total of 217 S. aureus isolated from different samples were processed following standard laboratory procedures. Antibiotic susceptibility testing was performed by the Kirby-Bauer disk diffusion technique. Methicillin-resistant S. aureus (MRSA) were identified by the cefoxitin disk diffusion test, and biofilm producers were examined using the microtiter plate technique. D-test and E-test were performed to determine inducible clindamycin resistance and minimum inhibitory concentration of vancomycin, respectively.

RESULTS: Among the 217 S. aureus isolates, 78.3% were multidrug-resistant (MDR), 47.0% were MRSA, 62.2% were biofilm producers, and 50.7% showed ICR. All MRSA isolates exhibited MIC levels of vancomycin within the susceptible range. Biofilm producers and MRSA isolates showed elevated antimicrobial resistance. MRSA was significantly associated with MDR. Biofilm-producing and multidrug-resistant MRSA isolates showed significantly higher MIC levels of vancomycin (p = 0.0013 and < 0.0001, respectively), while ICR was significantly higher in MDR (p = 0.0001) isolates.

CONCLUSION: High multidrug resistance, MRSA, and ICR in this study call for routine evaluation of antibiotic susceptibility patterns of S. aureus. Vancomycin can be used to treat serious staphylococcal infections. Clindamycin should be prescribed only after performing the D-test. Drugs like teicoplanin, chloramphenicol, doxycycline, amikacin, and levofloxacin can treat MRSA infections.}, } @article {pmid36131275, year = {2022}, author = {Rezaei, A and Hashemi, FB and Heshteli, RR and Rahmani, M and Halimi, S}, title = {Frequency of Salmonella serotypes among children in Iran: antimicrobial susceptibility, biofilm formation, and virulence genes.}, journal = {BMC pediatrics}, volume = {22}, number = {1}, pages = {557}, pmid = {36131275}, issn = {1471-2431}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology ; Biofilms ; Child ; Child, Preschool ; Drug Resistance, Bacterial/genetics ; Drug Resistance, Multiple, Bacterial/genetics ; *Gastroenteritis ; Humans ; Iran/epidemiology ; Microbial Sensitivity Tests ; Salmonella/genetics ; *Salmonella Infections/drug therapy/epidemiology ; Serogroup ; Virulence/genetics ; }, abstract = {BACKGROUND/SIGNIFICANCE: Salmonella gastroenteritis causes significant morbidity among pediatric patients, mainly in developing world, such as the Middle East and North Africa (MENA) region. Concurrently, data from MENA countries like Iran, regarding prevalence of Salmonella serotypes, antimicrobial susceptibility, and biofilm production is scarce.

MATERIAL & METHODS: Slide agglutination was used to determine the serogroup of 140 Salmonella isolates recovered from 4477 stool specimens collected from children with gastroenteritis, and isolates were serotyped by PCR assay. The antimicrobial susceptibility of isolates to five first line drugs was assessed by disk diffusion assay using CLSI guidelines. Semi-quantitative evaluation of biofilm production was done by microtiter plate assay followed by PCR detection of biofilm-associated virulence genes csgD, pefA, and bcsA for each isolate.

RESULTS: Nearly 94% of Salmonella isolates were recovered from ≤ 5-year-old patients, and 99% of isolates were non-typhoidal. While we found extensive diversity among Salmonella isolates, serogroup D (46%) predominated, and Salmonella Enteritidis (41%) was the most common serotype that showed the highest antimicrobial susceptibility rate (> 96%). For the first time in Iran, S. Newport serotype from human specimens was isolated. Most isolates were sensitive to all test antimicrobials, but 35% of isolates were not-typed (NT) that showed the highest resistance with 48% being resistant to ≥ 1 test antimicrobial. Majority of isolates made weak (or no) biofilm, and we found a weak association between antimicrobial susceptibility, biofilm production, or virulence genes csgD, pefA, and bcsA.

CONCLUSIONS: The most effective measure that may control pediatric salmonellosis outbreaks is raising awareness of parents of preschoolers about food safety. Isolation of highly diverse Salmonella serotypes, including many commonly isolated from animals, indicates widespread contamination of the food chain. Majority of serotypes were sensitive to first-line antimicrobials, thus presently, pediatric Salmonella infections in this region may be controlled by conventional antimicrobials. However, despite the current trend, an imminent emergence of resistant Salmonella strains is foreseen, since various serotypes resistant to > 1 antimicrobial agent are typically associated with animals. Our results warrant further investigation that includes correlation analysis of clinical data regarding treatment outcomes, and serotype attributes like virulence genes.}, } @article {pmid36129311, year = {2022}, author = {Létoffé, S and Wu, Y and Darch, SE and Beloin, C and Whiteley, M and Touqui, L and Ghigo, JM}, title = {Pseudomonas aeruginosa Production of Hydrogen Cyanide Leads to Airborne Control of Staphylococcus aureus Growth in Biofilm and In Vivo Lung Environments.}, journal = {mBio}, volume = {13}, number = {5}, pages = {e0215422}, pmid = {36129311}, issn = {2150-7511}, mesh = {Animals ; Mice ; Pseudomonas aeruginosa/physiology ; Staphylococcus aureus ; Hydrogen Cyanide ; *Cystic Fibrosis/microbiology ; Biofilms ; *Staphylococcal Infections/microbiology ; Lung ; Oxygen ; *Pseudomonas Infections/microbiology ; }, abstract = {Diverse bacterial volatile compounds alter bacterial stress responses and physiology, but their contribution to population dynamics in polymicrobial communities is not well known. In this study, we showed that airborne volatile hydrogen cyanide (HCN) produced by a wide range of Pseudomonas aeruginosa clinical strains leads to at-a-distance in vitro inhibition of the growth of a wide array of Staphylococcus aureus strains. We determined that low-oxygen environments not only enhance P. aeruginosa HCN production but also increase S. aureus sensitivity to HCN, which impacts P. aeruginosa-S. aureus competition in microaerobic in vitro mixed biofilms as well as in an in vitro cystic fibrosis lung sputum medium. Consistently, we demonstrated that production of HCN by P. aeruginosa controls S. aureus growth in a mouse model of airways coinfected by P. aeruginosa and S. aureus. Our study therefore demonstrates that P. aeruginosa HCN contributes to local and distant airborne competition against S. aureus and potentially other HCN-sensitive bacteria in contexts relevant to cystic fibrosis and other polymicrobial infectious diseases. IMPORTANCE Airborne volatile compounds produced by bacteria are often only considered attractive or repulsive scents, but they also directly contribute to bacterial physiology. Here, we showed that volatile hydrogen cyanide (HCN) released by a wide range of Pseudomonas aeruginosa strains controls Staphylococcus aureus growth in low-oxygen in vitro biofilms or aggregates and in vivo lung environments. These results are of pathophysiological relevance, since lungs of cystic fibrosis patients are known to present microaerobic areas and to be commonly associated with the presence of S. aureus and P. aeruginosa in polymicrobial communities. Our study therefore provides insights into how a bacterial volatile compound can contribute to the exclusion of S. aureus and other HCN-sensitive competitors from P. aeruginosa ecological niches. It opens new perspectives for the management or monitoring of P. aeruginosa infections in lower-lung airway infections and other polymicrobial disease contexts.}, } @article {pmid36128574, year = {2022}, author = {Nemchenko, UM and Sitnikova, KO and Belkova, NL and Grigorova, EV and Voropaeva, NM and Sukhоreva, MV and Sukhareva, ES and Savilov, ED}, title = {Effects of аntimicrobials on Pseudomonas aeruginosa biofilm formation.}, journal = {Vavilovskii zhurnal genetiki i selektsii}, volume = {26}, number = {5}, pages = {495-501}, doi = {10.18699/VJGB-22-60}, pmid = {36128574}, issn = {2500-0462}, abstract = {Pseudomonas aeruginosa is one of the most problematic pathogens in medical institutions, which may be due to the ability of this microorganism to exist in a biofilm, which increases its resistance to antimicrobials, as well as its prevalence and survival ability in the external environment. This work aimed to evaluate the antimicrobial susceptibility of P. aeruginosa strains in planktonic and biofilm forms. We studied 20 strains of P. aeruginosa collected during 2018-2021 by specialists from the Laboratory of Microbiome and Microecology of the Scientific Centre for Family Health and Human Reproduction Problems. The identification of strains was carried out using test systems for differentiating gram-negative non-fermenting bacteria (NEFERMtest 24 Erba Lachema s.r.o., Czech Republic), and confirmed by mass spectrometric analysis and 16S rRNA gene sequencing. Antimicrobial activity was assessed by the degree of inhibition of cell growth in planktonic and biofilm forms (on a flat-bottomed 96-well plastic immunological plate). All clinical isolates of P. aeruginosa were biofilm formers, 47.6 % of the isolates were weak biofilm formers, and 52.4 % of the isolates were moderate biofilm formers. Planktonic cells and the forming biofilm of the tested P. aeruginosa strains were carbapenems-resistant. Biofilm formation was suppressed in more than 90 % of cases by the agents of the cephalosporin and aminoglycoside groups. Antimicrobial susceptibility of P. aeruginosa strains in the formed biofilm was significantly lower (p < 0.05). Carbapenems and cephalosporins did not affect the mature biofilms of the tested P. aeruginosa strains in more than 60 % of cases. Only non-beta-lactam antibiotics (ciprofloxacin and amikacin) suppressed the growth of planktonic cells and destroyed the mature biofilm. The revealed differences in the effect of the tested antimicrobials on the P. aeruginosa strains biofilms correlate with resistance to a number of antibiotics. To prevent biofilm formation in the hospital strains of P. aeruginosa, the use of ceftazidime may be recommended, and antimicrobials such as ciprofloxacin and amikacin may be used to affect mature biofilms of P. aeruginosa.}, } @article {pmid36128224, year = {2022}, author = {Dey, A and Yadav, M and Kumar, D and Dey, AK and Samal, S and Tanwar, S and Sarkar, D and Pramanik, SK and Chaudhuri, S and Das, A}, title = {A combination therapy strategy for treating antibiotic resistant biofilm infection using a guanidinium derivative and nanoparticulate Ag(0) derived hybrid gel conjugate.}, journal = {Chemical science}, volume = {13}, number = {34}, pages = {10103-10118}, pmid = {36128224}, issn = {2041-6520}, abstract = {Bacteria organized in biofilms show significant tolerance to conventional antibiotics compared to their planktonic counterparts and form the basis for chronic infections. Biofilms are composites of different types of extracellular polymeric substances that help in resisting several host-defense measures, including phagocytosis. These are increasingly being recognized as a passive virulence factor that enables many infectious diseases to proliferate and an essential contributing facet to anti-microbial resistance. Thus, inhibition and dispersion of biofilms are linked to addressing the issues associated with therapeutic challenges imposed by biofilms. This report is to address this complex issue using a self-assembled guanidinium-Ag(0) nanoparticle (AD-L@Ag(0)) hybrid gel composite for executing a combination therapy strategy for six difficult to treat biofilm-forming and multidrug-resistant bacteria. Improved efficacy was achieved primarily through effective biofilm inhibition and dispersion by the cationic guanidinium ion derivative, while Ag(0) contributes to the subsequent bactericidal activity on planktonic bacteria. Minimum Inhibitory Concentration (MIC) of the AD-L@Ag(0) formulation was tested against Acinetobacter baumannii (25 μg mL[-1]), Pseudomonas aeruginosa (0.78 μg mL[-1]), Staphylococcus aureus (0.19 μg mL[-1]), Klebsiella pneumoniae (0.78 μg mL[-1]), Escherichia coli (clinical isolate (6.25 μg mL[-1])), Klebsiella pneumoniae (clinical isolate (50 μg mL[-1])), Shigella flexneri (clinical isolate (0.39 μg mL[-1])) and Streptococcus pneumoniae (6.25 μg mL[-1]). Minimum bactericidal concentration, and MBIC50 and MBIC90 (Minimum Biofilm Inhibitory Concentration at 50% and 90% reduction, respectively) were evaluated for these pathogens. All these results confirmed the efficacy of the formulation AD-L@Ag(0). Minimum Biofilm Eradication Concentration (MBEC) for the respective pathogens was examined by following the exopolysaccharide quantification method to establish its potency in inhibition of biofilm formation, as well as eradication of mature biofilms. These effects were attributed to the bactericidal effect of AD-L@Ag(0) on biofilm mass-associated bacteria. The observed efficacy of this non-cytotoxic therapeutic combination (AD-L@Ag(0)) was found to be better than that reported in the existing literature for treating extremely drug-resistant bacterial strains, as well as for reducing the bacterial infection load at a surgical site in a small animal BALB/c model. Thus, AD-L@Ag(0) could be a promising candidate for anti-microbial coatings on surgical instruments, wound dressing, tissue engineering, and medical implants.}, } @article {pmid36127658, year = {2022}, author = {Aherne, O and Ortiz, R and Fazli, MM and Davies, JR}, title = {Effects of stabilized hypochlorous acid on oral biofilm bacteria.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {415}, pmid = {36127658}, issn = {1472-6831}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; Hydroxyapatites/pharmacology ; *Hypochlorous Acid/pharmacology ; Streptococcus mutans ; }, abstract = {BACKGROUND: Caries and periodontitis are amongst the most prevalent diseases worldwide, leading to pain and loss of oral function for those affected. Prevention relies heavily on mechanical removal of dental plaque biofilms but for populations where this is not achievable, alternative plaque control methods are required. With concerns over undesirable side-effects and potential bacterial resistance due to the use of chlorhexidine gluconate (CHX), new antimicrobial substances for oral use are greatly needed. Here we have investigated the antimicrobial effect of hypochlorous acid (HOCl), stabilized with acetic acid (HAc), on oral biofilms and compared it to that of CHX. Possible adverse effects of stabilized HOCl on hydroxyapatite surfaces were also examined.

METHODS: Single- and mixed-species biofilms of six common oral bacteria (Streptococcus mutans, Streptococcus gordonii, Actinomyces odontolyticus, Veillonella parvula, Parvimonas micra and Porphyromonas gingivalis) within a flow-cell model were exposed to HOCl stabilized with 0.14% or 2% HAc, pH 4.6, as well as HOCl or HAc alone. Biofilm viability was assessed in situ using confocal laser scanning microscopy following LIVE/DEAD® BacLight™ staining. In-situ quartz crystal microbalance with dissipation (QCM-D) was used to study erosion of hydroxyapatite (HA) surfaces by stabilized HOCl.

RESULTS: Low concentrations of HOCl (5 ppm), stabilized with 0.14% or 2% HAc, significantly reduced viability in multi-species biofilms representing supra- and sub-gingival oral communities, after 5 min, without causing erosion of HA surfaces. No equivalent antimicrobial effect was seen for CHX. Gram-positive and Gram-negative bacteria showed no significant differential suceptibility to stabilized HOCl.

CONCLUSIONS: At low concentrations and with exposure times which could be achieved through oral rinsing, HOCl stabilized with HAc had a robust antimicrobial activity on oral biofilms, without causing erosion of HA surfaces or affecting viability of oral keratinocytes. This substance thus appears to offer potential for prevention and/or treatment of oral biofilm-mediated diseases.}, } @article {pmid36127648, year = {2022}, author = {Xia, M and Zhuo, N and Ren, S and Zhang, H and Yang, Y and Lei, L and Hu, T}, title = {Enterococcus faecalis rnc gene modulates its susceptibility to disinfection agents: a novel approach against biofilm.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {416}, pmid = {36127648}, issn = {1472-6831}, mesh = {Chlorhexidine/pharmacology ; *Disinfectants ; Disinfection ; *Enterococcus faecalis/genetics ; Gentian Violet/pharmacology ; Humans ; Ribonuclease III/pharmacology ; Sodium Hypochlorite/pharmacology ; Virulence Factors/pharmacology ; }, abstract = {BACKGROUND: Enterococcus faecalis (E. faecalis) plays an important role in the failure of root canal treatment and refractory periapical periodontitis. As an important virulence factor of E. faecalis, extracellular polysaccharide (EPS) serves as a matrix to wrap bacteria and form biofilms. The homologous rnc gene, encoding Ribonuclease III, has been reported as a regulator of EPS synthesis. In order to develop novel anti-biofilm targets, we investigated the effects of the rnc gene on the biological characteristics of E. faecalis, and compared the biofilm tolerance towards the typical root canal irrigation agents and traditional Chinese medicine fluid Pudilan.

METHODS: E. faecalis rnc gene overexpression (rnc+) and low-expression (rnc-) strains were constructed. The growth curves of E. faecalis ATCC29212, rnc+, and rnc- strains were obtained to study the regulatory effect of the rnc gene on E. faecalis. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and crystal violet staining assays were performed to evaluate the morphology and composition of E. faecalis biofilms. Furthermore, the wild-type and mutant biofilms were treated with 5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and Pudilan. The residual viabilities of E. faecalis biofilms were evaluated using crystal violet staining and colony counting assays.

RESULTS: The results demonstrated that the rnc gene could promote bacterial growth and EPS synthesis, causing the EPS-barren biofilm morphology and low EPS/bacteria ratio. Both the rnc+ and rnc- biofilms showed increased susceptibility to the root canal irrigation agents. The 5% NaOCl group showed the highest biofilm removing effect followed by Pudilan and 2% CHX. The colony counting results showed almost complete removal of bacteria in the 5% NaOCl, 2% CHX, and Chinese medicine agents' groups.

CONCLUSIONS: This study concluded that the rnc gene could positively regulate bacterial proliferation, EPS synthesis, and biofilm formation in E. faecalis. The rnc mutation caused an increase in the disinfectant sensitivity of biofilm, indicating a potential anti-biofilm target. In addition, Pudilan exhibited an excellent ability to remove E. faecalis biofilm.}, } @article {pmid36127518, year = {2023}, author = {Flemming, HC and van Hullebusch, ED and Neu, TR and Nielsen, PH and Seviour, T and Stoodley, P and Wingender, J and Wuertz, S}, title = {The biofilm matrix: multitasking in a shared space.}, journal = {Nature reviews. Microbiology}, volume = {21}, number = {2}, pages = {70-86}, pmid = {36127518}, issn = {1740-1534}, mesh = {*Extracellular Polymeric Substance Matrix ; *Biofilms ; DNA ; Polysaccharides ; Proteins ; }, abstract = {The biofilm matrix can be considered to be a shared space for the encased microbial cells, comprising a wide variety of extracellular polymeric substances (EPS), such as polysaccharides, proteins, amyloids, lipids and extracellular DNA (eDNA), as well as membrane vesicles and humic-like microbially derived refractory substances. EPS are dynamic in space and time and their components interact in complex ways, fulfilling various functions: to stabilize the matrix, acquire nutrients, retain and protect eDNA or exoenzymes, or offer sorption sites for ions and hydrophobic substances. The retention of exoenzymes effectively renders the biofilm matrix an external digestion system influencing the global turnover of biopolymers, considering the ubiquitous relevance of biofilms. Physico-chemical and biological interactions and environmental conditions enable biofilm systems to morph into films, microcolonies and macrocolonies, films, ridges, ripples, columns, pellicles, bubbles, mushrooms and suspended aggregates - in response to the very diverse conditions confronting a particular biofilm community. Assembly and dynamics of the matrix are mostly coordinated by secondary messengers, signalling molecules or small RNAs, in both medically relevant and environmental biofilms. Fully deciphering how bacteria provide structure to the matrix, and thus facilitate and benefit from extracellular reactions, remains the challenge for future biofilm research.}, } @article {pmid36126788, year = {2022}, author = {Figueroa-Valenzuela, C and Montes-García, JF and Vazquez-Cruz, C and Zenteno, E and Pereyra, MA and Negrete-Abascal, E}, title = {Mannheimia haemolytica OmpH binds fibrinogen and fibronectin and participates in biofilm formation.}, journal = {Microbial pathogenesis}, volume = {172}, number = {}, pages = {105788}, doi = {10.1016/j.micpath.2022.105788}, pmid = {36126788}, issn = {1096-1208}, mesh = {Cattle ; Animals ; Sheep ; Rabbits ; *Mannheimia haemolytica ; Fibronectins ; Fibrinogen ; *Pasteurella multocida ; Biofilms ; Virulence Factors ; Bacterial Outer Membrane Proteins ; }, abstract = {Mannheimia haemolytica is the causal agent of the shipping fever in bovines and produces high economic losses worldwide. This bacterium possesses different virulence attributes to achieve a successful infection. One of the main virulence factors expressed by a pathogen is through adhesion molecules; however, the components participating in this process are not totally known. The present work identified a M. haemolytica 41 kDa outer membrane protein (Omp) that participates in bacterial adhesion. This protein showed 100% identity with the OmpH from M. haemolytica as determined by mass spectrometry and it interacts with sheep fibrinogen. The 41 kDa M. haemolytica OmpH interacts with bovine monocytes; a previous incubation of M. haemolytica with a rabbit hyperimmune serum against this Omp diminished 45% cell adhesion. The OmpH was recognized by serum from bovines affected by acute or chronic pneumonia, indicating its in vivo expression; moreover, it showed immune cross-reaction with the serum of rabbit infected with Pasteurella multocida. The OmpH is present in biofilms and previous incubation of M. haemolytca with rabbit serum against this protein diminished biofilm, indicating this protein's participation in biofilm formation. M. haemolytica OmpH is proposed as a relevant immunogen in bovine pneumonia protection.}, } @article {pmid36126711, year = {2023}, author = {Farooq, AJ and Chamberlain, M and Poonja, A and Mumford, KG and Wallace, S and Weber, KP}, title = {Peaks, pores, and dragon eggs: Uncovering and quantifying the heterogeneity of treatment wetland biofilm matrices.}, journal = {The Science of the total environment}, volume = {855}, number = {}, pages = {158857}, doi = {10.1016/j.scitotenv.2022.158857}, pmid = {36126711}, issn = {1879-1026}, mesh = {*Wetlands ; Extracellular Polymeric Substance Matrix ; Wastewater ; Biofilms ; *Environmental Pollutants ; }, abstract = {Biofilms serve to house diverse microbial communities, which are responsible for the majority of wastewater constituent degradation and transformation in treatment wetlands (TWs). TW biofilm has been generally conceptualized as a relatively uniform film covering available surfaces. However, no studies attaining direct visual 3D representations of biofilm morphology have been conducted. This study focuses on imaging the morphology of detached, gravel-associated, and rhizospheric (Phalaris arundinacea) biofilms from subsurface TW mesocosms. Images obtained through both traditional light microscopy, environmental scanning electron microscopy (E-SEM) and Wet-SEM revealed that TW biofilms are structurally heterogeneous ranging from corrugated films to clusters of aggregates. Features such as water channels and pores were observed suggesting that pollutant transport inside biofilms is complex, and that the interfacial surface area between water and biofilm is much larger than previously understood. Biofilm thickness generally ranged between 170 and 240 μm, with internal biofilm porosities estimated as 34 ± 10 %, reaching a maximum of 50 %. Internal biofilm matrix pore diameters ranged from 1 to 205.2 μm, with a distribution that favored pores and channels smaller than 10 μm, and a mean equivalent spherical diameter of 8.6 μm. Based on the large variation in pore and channel sizes it is expected that a variety of flow regimes and therefore pollutant dynamics are likely to occur inside TW biofilm matrices. Based on the visual evidence and analysis, a new conceptual model was created to reflect the microscale TW biofilm dynamics and morphology. This new conceptual model will serve to inform future biokinetic modelling, microscale hydrology, microbial community assessment, and pollutant treatment studies.}, } @article {pmid36126311, year = {2022}, author = {Chakroun, I and Fedhila, K and Maatallah, M and Mzoughi, R and Bakhrouf, A and Krichen, Y}, title = {The Synbiotic Effect of Probiotics and Dried Spirulina platensis or Phycocyanin on Biofilm Formation by Salmonella Typhimurium and Staphylococcus aureus.}, journal = {Foodborne pathogens and disease}, volume = {19}, number = {10}, pages = {655-662}, doi = {10.1089/fpd.2022.0008}, pmid = {36126311}, issn = {1556-7125}, mesh = {Humans ; Phycocyanin/pharmacology ; Staphylococcus aureus ; Salmonella typhimurium ; *Synbiotics ; *Probiotics/pharmacology ; Biofilms ; }, abstract = {This study aimed to evaluate the synbiotic effect of probiotics and dried Spirulina platensis or phycocyanin on autoaggregation, coaggregation, and the inhibition of biofilm formation by Salmonella Typhimurium and Staphylococcus aureus on 96-well microtiter plates and Human colon carcinoma cells-116 surfaces. The results showed that the probiotics strains cultured in the presence of S. platensis exhibited the highest autoaggregation values, ranging between 68.5 and 74.2% after 24 h. All probiotic strains with or without S. platensis and phycocyanin showed coaggregation abilities with S. Typhimurium and S. aureus. Interestingly, significant effect of S. platensis and phycocyanin supplementation was observed on the inhibition of the biofilm formation by the selected pathogens during the competition, exclusion, and displacement on abiotic and biotic surfaces.}, } @article {pmid36126071, year = {2022}, author = {Dos Santos, RL and Davanzo, EFA and Palma, JM and Castro, VHL and da Costa, HMB and Dallago, BSL and Perecmanis, S and Santana, ÂP}, title = {Molecular characterization and biofilm-formation analysis of Listeria monocytogenes, Salmonella spp., and Escherichia coli isolated from Brazilian swine slaughterhouses.}, journal = {PloS one}, volume = {17}, number = {9}, pages = {e0274636}, pmid = {36126071}, issn = {1932-6203}, mesh = {Abattoirs ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Brazil ; Cefazolin ; Chloramphenicol ; Doxycycline ; Drug Resistance, Bacterial/genetics ; Escherichia coli ; *Escherichia coli Infections ; Escherichia coli Proteins ; Gentamicins ; *Listeria monocytogenes/genetics ; Nalidixic Acid ; Salmonella ; Streptomycin ; Sulfonamides ; Swine ; }, abstract = {This study aimed to verify the presence of Listeria monocytogenes, Salmonella spp., and Escherichia coli in two Brazilian swine slaughterhouses, as well as to perform antibiograms, detect virulence and antimicrobial resistance genes, and evaluate the in vitro biofilm-forming capability of bacterial isolates from these environments. One Salmonella Typhi isolate and 21 E. coli isolates were detected, while L. monocytogenes was not detected. S. Typhi was isolated from the carcass cooling chamber's floor, resistant to several antimicrobials, including nalidixic acid, cefazolin, chloramphenicol, doxycycline, streptomycin, gentamicin, tetracycline, and sulfonamide, and contained resistance genes, such as tet(B), tet(C), tet(M), and ampC. It also showed moderate biofilm-forming capacity at 37°C after incubating for 72 h. The prevalence of the 21 E. coli isolates was also the highest on the carcass cooling chamber floor (three of the four samplings [75%]). The E. coli isolates were resistant to 12 of the 13 tested antimicrobials, and none showed sensitivity to chloramphenicol, an antimicrobial prohibited in animal feed since 2003 in Brazil. The resistance genes MCR-1, MCR-3, sul1, ampC, clmA, cat1, tet(A), tet(B), and blaSHV, as well as the virulence genes stx-1, hlyA, eae, tir α, tir β, tir γ, and saa were detected in the E. coli isolates. Moreover, 5 (23.8%) and 15 (71.4%) E. coli isolates presented strong and moderate biofilm-forming capacity, respectively. In general, the biofilm-forming capacity increased after incubating for 72 h at 10°C. The biofilm-forming capacity was the lowest after incubating for 24 h at 37°C. Due to the presence of resistance and virulence genes, multi-antimicrobial resistance, and biofilm-forming capacity, the results of this study suggest a risk to the public health as these pathogens are associated with foodborne diseases, which emphasizes the hazard of resistance gene propagation in the environment.}, } @article {pmid36125823, year = {2023}, author = {Keikha, M and Karbalaei, M}, title = {Biofilm Formation Status in ESBL-Producing Bacteria Recovered from Clinical Specimens of Patients: A Systematic Review and Meta-Analysis.}, journal = {Infectious disorders drug targets}, volume = {23}, number = {2}, pages = {65-72}, doi = {10.2174/1871526522666220920141631}, pmid = {36125823}, issn = {2212-3989}, mesh = {Humans ; *beta-Lactamases/genetics ; *Bacteria ; Anti-Bacterial Agents/pharmacology ; Biofilms ; }, abstract = {BACKGROUND: Recently, the emergence and spread of extended-spectrum beta-lactamase (ESBL) bacteria have become a global health concern. In addition, the ability to form biofilm due to less impermeability to antibiotics and the horizontal transformation (conjugation) of genes involved in antibiotic resistance have exacerbated the concerns. With a comprehensive meta-analysis, this study evaluated the potential relationship between ESBL and biofilm formation.

METHODS: A literature search was performed using global databases, such as PubMed and Scopus, up to November 2021. We retrieved all relevant documents and selected eligible articles based on inclusion criteria. Finally, the potential association between the biofilm formation capacity and resistance of ESBL-producing bacteria was measured with an odds ratio and a 95% confidence interval.

RESULTS: In the present study, 17 articles, including 2,069 Gram-negative isolates, were considered as eligible. The prevalence of biofilm formation in all clinical isolates of ESBL and non-ESBL pathogens was 72.4% (95% CI: 60.7-81.6) and 40.5% (95% CI: 30.2-51.8), respectively. Our results showed a positive relationship between the ability for biofilm formation and conferring antibiotic resistance in ESBL-producing bacteria (OR: 3.35; 95% CI: 1.67-6.74; p-value: 0.001).

CONCLUSION: In general, we showed the rate of biofilm formation to be significantly higher in ESBLproducing strains. Given the current results, the updated therapeutic guidelines should consider the role of biofilm production for optimal therapy, treatment course, and clinical outcomes rather than the recommendation of antimicrobial agents by focusing on the results of the antibiotic susceptibility test.}, } @article {pmid36125767, year = {2022}, author = {Nercessian, D and Busalmen, JP}, title = {Cell Adhesion and Biofilm Formation Analysis.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2522}, number = {}, pages = {407-417}, pmid = {36125767}, issn = {1940-6029}, mesh = {*Archaea ; Bacteria ; *Biofilms ; Cell Adhesion ; Cell Aggregation ; }, abstract = {Cell adhesion to surfaces and ulterior biofilm formation are critical processes in microbial development since living in biofilms is the preferred way of life within microorganisms. These processes are known to influence not only microorganisms development in the environment, but also their participation in biotechnological processes and have been the focus of intense research that as a matter of fact, was mainly directed to the bacterial domain. Archaea also adhere to surfaces and have been shown forming biofilms, but studies performed until present did not exploit the diversity of methods probed to be useful along bacterial biofilm research.An experimental setup is described here with the aim of stimulating archaeal biofilm research. It can be used for studying cell adhesion and biofilm formation under controlled flow conditions and allows performing in situ optical microscopy (phase contrast, fluorescence, or confocal) and/or spectroscopic techniques (UV-Vis, IR, or Raman) to determine structural and functional biofilm features and their evolution in time. Variants are described with specific aims as working in anaerobiosis and allow sampling of biological material along time.}, } @article {pmid36125765, year = {2022}, author = {Mutan, Z and Schiller, H and Schulze, S and Pohlschroder, M}, title = {Immersed Liquid Biofilm and Honeycomb Pattern Formations in Haloferax volcanii.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2522}, number = {}, pages = {387-395}, pmid = {36125765}, issn = {1940-6029}, mesh = {Bacteria ; Biofilms ; *Haloferax volcanii/genetics ; }, abstract = {Biofilms are cellular aggregates encased in extracellular polymeric substances and are commonly formed by single-celled eukaryotes, bacteria, and archaea. In addition to attaching to solid surfaces, these cellular aggregates can also be observed floating on or immersed within liquid cultures. While biofilms on surfaces have been studied in some archaea, little is known about liquid biofilms. Surprisingly, immersed liquid biofilms of the model archaeon Haloferax volcanii do not require the same set of machinery needed to form surface-attached biofilms. In fact, to date not a single gene has been identified that is involved in forming immersed liquid biofilms. Interestingly, after an immersed liquid biofilm forms, removal of the Petri dish lid induces rapid, transient, and reproducible honeycomb patterns within the immersed liquid biofilm itself, triggered by a reduction in humidity. In this chapter, we outline a protocol for both immersed liquid biofilm and honeycomb pattern formations. This protocol will be essential for determining the novel components required for the formation of immersed liquid biofilms and honeycomb patterns.}, } @article {pmid36124328, year = {2022}, author = {Oluwole, OM}, title = {BIOFILM: FORMATION AND NATURAL PRODUCTS' APPROACH TO CONTROL - A REVIEW.}, journal = {African journal of infectious diseases}, volume = {16}, number = {2 Suppl}, pages = {59-71}, pmid = {36124328}, issn = {2006-0165}, abstract = {Biofilm formation, especially on indwelling medical devices such as catheters, can result in infections and substantially affect patients' quality of life. Biofilm-associated infections have led to increased morbidity and mortality, increased cost of treatment, and length of hospital stay. However, all of the identified consequences of the biofilm-associated infections had been attributed to the reduced susceptibility of biofilm to conventional antimicrobial agents which has necessitated the development of a new strategy for biofilm infections control, thereby making a search for more effective antimicrobial agents from plant source inevitable. So far, some antimicrobial agents (crude or isolated compounds) from plant sources affect a specific stage of biofilm development while a few of them have been developed into a suitable dosage form for biofilm control. In this review, an attempt is made to look into some definitions of biofilm by "biofilmologists", stages in biofilm formation, mechanisms of resistance in biofilm, biofilm control strategies, the use of some natural products in biofilm control and concepts of probiotics as agents of biofilm control.}, } @article {pmid36123439, year = {2022}, author = {Purtschert-Montenegro, G and Cárcamo-Oyarce, G and Pinto-Carbó, M and Agnoli, K and Bailly, A and Eberl, L}, title = {Pseudomonas putida mediates bacterial killing, biofilm invasion and biocontrol with a type IVB secretion system.}, journal = {Nature microbiology}, volume = {7}, number = {10}, pages = {1547-1557}, pmid = {36123439}, issn = {2058-5276}, support = {169307/SNSF_/Swiss National Science Foundation/Switzerland ; }, mesh = {Biofilms ; *Solanum lycopersicum/microbiology ; *Pseudomonas putida/genetics ; *Ralstonia solanacearum ; Soil ; }, abstract = {Many bacteria utilize contact-dependent killing machineries to eliminate rivals in their environmental niches. Here we show that the plant root colonizer Pseudomonas putida strain IsoF is able to kill a wide range of soil and plant-associated Gram-negative bacteria with the aid of a type IVB secretion system (T4BSS) that delivers a toxic effector into bacterial competitors in a contact-dependent manner. This extends the range of targets of T4BSSs-so far thought to transfer effectors only into eukaryotic cells-to prokaryotes. Bioinformatic and genetic analyses showed that this killing machine is entirely encoded by the kib gene cluster located within a rare genomic island, which was recently acquired by horizontal gene transfer. P. putida IsoF utilizes this secretion system not only as a defensive weapon to kill bacterial competitors but also as an offensive weapon to invade existing biofilms, allowing the strain to persist in its natural environment. Furthermore, we show that strain IsoF can protect tomato plants against the phytopathogen Ralstonia solanacearum in a T4BSS-dependent manner, suggesting that IsoF can be exploited for pest control and sustainable agriculture.}, } @article {pmid36123299, year = {2023}, author = {Allkja, J and Goeres, DM and Azevedo, AS and Azevedo, NF}, title = {Interactions of microorganisms within a urinary catheter polymicrobial biofilm model.}, journal = {Biotechnology and bioengineering}, volume = {120}, number = {1}, pages = {239-249}, doi = {10.1002/bit.28241}, pmid = {36123299}, issn = {1097-0290}, support = {//Fundação para a Ciência e a Tecnologia/ ; //FEDER/ ; //FCT/MCTES (PIDDAC)/ ; }, mesh = {*Urinary Catheters/microbiology ; Escherichia coli/genetics ; In Situ Hybridization, Fluorescence ; Proteus mirabilis/genetics ; Biofilms ; *Urinary Tract Infections/prevention & control ; Candida albicans ; }, abstract = {Biofilms are often polymicrobial in nature, which can impact their behavior and overall structure, often resulting in an increase in biomass and enhanced antimicrobial resistance. Using plate counts and locked nucleic acid/2'-O-methyl-RNA fluorescence in situ hybridization (LNA/2'OMe-FISH), we studied the interactions of four species commonly associated with catheter-associated urinary tract infections (CAUTI): Enterococcus faecalis, Escherichia coli, Candida albicans, and Proteus mirabilis. Eleven combinations of biofilms were grown on silicone coupons placed in 24-well plates for 24 h, 37°C, in artificial urine medium (AUM). Results showed that P. mirabilis was the dominant species and was able to inhibit both E. coli and C. albicans growth. In the absence of P. mirabilis, an antagonistic relationship between E. coli and C. albicans was observed, with the former being dominant. E. faecalis growth was not affected in any combination, showing a more mutualistic relationship with the other species. Imaging results correlated with the plate count data and provided visual verification of species undetected using the viable plate count. Moreover, the three bacterial species showed overall good repeatability SD (Sr) values (0.1-0.54) in all combinations tested, whereas C. albicans had higher repeatability Sr values (0.36-1.18). The study showed the complexity of early-stage interactions in polymicrobial biofilms. These interactions could serve as a starting point when considering targets for preventing or treating CAUTI biofilms containing these species.}, } @article {pmid36121578, year = {2022}, author = {Rathore, SS and Cheepurupalli, L and Gangwar, J and Raman, T and Ramakrishnan, J}, title = {Biofilm of Klebsiella pneumoniae minimize phagocytosis and cytokine expression by macrophage cell line.}, journal = {AMB Express}, volume = {12}, number = {1}, pages = {122}, pmid = {36121578}, issn = {2191-0855}, support = {(EMR/2016/007613)//Science and Engineering Research Board (SERB)/ ; }, abstract = {Infectious bacteria in biofilm mode are involved in many persistent infections. Owing to its importance in clinical settings, many in vitro and in vivo studies are being conducted to study the structural and functional properties of biofilms, their drug resistant mechanism and the s urvival mechanism of planktonic and biofilm cells. In this regard, there is not sufficient information on the interaction between Klebsiella biofilm and macrophages. In this study, we have attempted to unravel the interaction between Klebsiella biofilm and macrophages in terms of phagocytic response and cytokine expression. In vitro phagocytosis assays were performed for heat inactivated and live biofilms of K. pneumoniae, together with the expression analysis of TLR2, iNOS, inflammatory cytokines such as IL-β1, IFN-γ, IL-6, IL-12, IL-4, TNF-α and anti-inflammatory cytokine, IL-10. A phagocytic rate of an average of 15% was observed against both heat inactivated and live biofilms when LPS + IFN-γ activated macrophages were used. This was significantly higher than non-activated macrophages when tested against heat inactivated and live biofilms (average 8%). Heat-inactivated and live biofilms induced similar phagocytic responses and up-regulation of pro-inflammatory genes in macrophages, indirectly conveying that macrophage responses are to some extent dependent on the biofilm matrix.}, } @article {pmid36121562, year = {2022}, author = {González-Paz, JR and Becerril-Varela, K and Guerrero-Barajas, C}, title = {Iron reducing sludge as a source of electroactive bacteria: assessing iron reduction in biofilm bacteria, planktonic cells and isolates from a microbial fuel cell.}, journal = {Archives of microbiology}, volume = {204}, number = {10}, pages = {632}, pmid = {36121562}, issn = {1432-072X}, support = {20221270//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; 20221270//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; 20221270//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; 20221270//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; }, mesh = {*Bioelectric Energy Sources/microbiology ; Biofilms ; Carbon ; Electricity ; Iron ; Plankton ; Sewage ; }, abstract = {In this study, bacteria from a microbial fuel cell (MFC) and isolates were evaluated on their Fe[3+] reduction capability at different concentrations of iron using acetate as the sole source of carbon. The results demonstrated that the planktonic cells can reach an iron reduction up to 60% at 27 mmol Fe[3+]. Azospira oryzae (µ 0.89 ± 0.27 d[-1]) and Cupriavidus metallidurans CH34 (µ 2.34 ± 0.81 d[-1]) presented 55 and 62% of Fe[3+] reduction, respectively, at 16 mmol l[-1]. Enterobacter bugandensis (µ 0.4 ± 0.01 d[-1]) 40% Fe[3+] at 27 mmol l[-1], Citrobacter freundii ATCC 8090 (µ 0.23 ± 0.05 d[-1]) and Citrobacter murliniae CDC2970-59 (µ 0.34 ± 0.02 d[-1]) reduced Fe[3+] in ~ 50%, at 55 mmol l[-1]. This is the first report on these bacteria on a percentage of iron reduction. These results may be useful for anode design to contribute to a higher energy generation in MFCs.}, } @article {pmid36121483, year = {2022}, author = {Gill, SP and Hunter, WR and Coulson, LE and Banat, IM and Schelker, J}, title = {Synthetic and biological surfactant effects on freshwater biofilm community composition and metabolic activity.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {19-20}, pages = {6847-6859}, pmid = {36121483}, issn = {1432-0614}, mesh = {Biofilms ; Ecosystem ; Fresh Water/chemistry ; Glucosidases/pharmacology ; *Leucyl Aminopeptidase/metabolism/pharmacology ; Sodium Dodecyl Sulfate ; *Surface-Active Agents/pharmacology ; Water/pharmacology ; }, abstract = {Surfactants are used to control microbial biofilms in industrial and medical settings. Their known toxicity on aquatic biota, and their longevity in the environment, has encouraged research on biodegradable alternatives such as rhamnolipids. While previous research has investigated the effects of biological surfactants on single species biofilms, there remains a lack of information regarding the effects of synthetic and biological surfactants in freshwater ecosystems. We conducted a mesocosm experiment to test how the surfactant sodium dodecyl sulfate (SDS) and the biological surfactant rhamnolipid altered community composition and metabolic activity of freshwater biofilms. Biofilms were cultured in the flumes using lake water from Lake Lunz in Austria, under high (300 ppm) and low (150 ppm) concentrations of either surfactant over a four-week period. Our results show that both surfactants significantly affected microbial diversity. Up to 36% of microbial operational taxonomic units were lost after surfactant exposure. Rhamnolipid exposure also increased the production of the extracellular enzymes, leucine aminopeptidase, and glucosidase, while SDS exposure reduced leucine aminopeptidase and glucosidase. This study demonstrates that exposure of freshwater biofilms to chemical and biological surfactants caused a reduction of microbial diversity and changes in biofilm metabolism, exemplified by shifts in extracellular enzyme activities. KEY POINTS: • Microbial biofilm diversity decreased significantly after surfactant exposure. • Exposure to either surfactant altered extracellular enzyme activity. • Overall metabolic activity was not altered, suggesting functional redundancy.}, } @article {pmid36121221, year = {2022}, author = {Tomlinson, BR and Denham, GA and Torres, NJ and Brzozowski, RS and Allen, JL and Jackson, JK and Eswara, PJ and Shaw, LN}, title = {Assessing the Role of Cold-Shock Protein C: a Novel Regulator of Acinetobacter baumannii Biofilm Formation and Virulence.}, journal = {Infection and immunity}, volume = {90}, number = {10}, pages = {e0037622}, pmid = {36121221}, issn = {1098-5522}, support = {R35 GM133617/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Acinetobacter baumannii/metabolism ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cold Shock Proteins and Peptides/genetics/metabolism ; Polysaccharides/metabolism ; Protein C/metabolism/pharmacology ; RNA/metabolism ; Virulence/genetics ; }, abstract = {Acinetobacter baumannii is a formidable opportunistic pathogen that is notoriously difficult to eradicate from hospital settings. This resilience is often attributed to a proclivity for biofilm formation, which facilitates a higher tolerance toward external stress, desiccation, and antimicrobials. Despite this, little is known regarding the mechanisms orchestrating A. baumannii biofilm formation. Here, we performed RNA sequencing (RNA-seq) on biofilm and planktonic populations for the multidrug-resistant isolate AB5075 and identified 438 genes with altered expression. To assess the potential role of genes upregulated within biofilms, we tested the biofilm-forming capacity of their respective mutants from an A. baumannii transposon library. In so doing, we uncovered 24 genes whose disruption led to reduced biofilm formation. One such element, cold shock protein C (cspC), had a highly mucoid colony phenotype, enhanced tolerance to polysaccharide degradation, altered antibiotic tolerance, and diminished adherence to abiotic surfaces. RNA-seq of the cspC mutant revealed 201 genes with altered expression, including the downregulation of pili and fimbria genes and the upregulation of multidrug efflux pumps. Using transcriptional arrest assays, it appears that CspC mediates its effects, at least in part, through RNA chaperone activity, influencing the half-life of several important transcripts. Finally, we show that CspC is required for survival during challenge by the human immune system and is key for A. baumannii dissemination and/or colonization during systemic infection. Collectively, our work identifies a cadre of new biofilm-associated genes within A. baumannii and provides unique insight into the global regulatory network of this emerging human pathogen.}, } @article {pmid36120528, year = {2022}, author = {Ghidini, S and De Luca, S and Rodríguez-López, P and Simon, AC and Liuzzo, G and Poli, L and Ianieri, A and Zanardi, E}, title = {Microbial contamination, antimicrobial resistance and biofilm formation of bacteria isolated from a high-throughput pig abattoir.}, journal = {Italian journal of food safety}, volume = {11}, number = {3}, pages = {10160}, pmid = {36120528}, issn = {2239-7132}, abstract = {The aim of this work was to assess the level of microbial contamination and resistance of bacteria isolated from a highthroughput heavy pig slaughterhouse (approx. 4600 pigs/day) towards antimicrobials considered as critical for human, veterinary or both chemotherapies. Samples, pre-operative and operative, were obtained in 4 different surveys. These comprised environmental sampling, i.e. air (ntotal = 192) and surfaces (ntotal = 32), in four different locations. Moreover, a total of 40 carcasses were sampled in two different moments of slaughtering following Reg. (CE) 2073/2005. Overall, 60 different colonies were randomly selected from VRBGA plates belonging to 20 species, 15 genera and 10 families being Enterobacteriaceae, Moraxellaceae and Pseudomonadaceae the most represented ones. Thirty-seven isolates presented resistance to at least one molecule and seventeen were classified as multi-drug resistant. Enterobacteriaceae, particularly E. coli, displayed high MIC values towards trimethoprim, ampicillin, tetracycline and sulphametoxazole with MICmax of 16, 32, 32 and 512 mg/L, respectively. Moreover, isolated Pseudomonas spp. showed high MIC values in critical antibiotics such as ampicillin and azithromycin with MICmax of 32 and 64 mg/L, respectively. Additionally, in vitro biofilm formation assays demonstrated that fifteen of these isolates can be classified as strong biofilm formers. Results demonstrated that a high diversity of bacteria containing antibiotic resistant and multiresistant species is present in the sampled abattoir. Considering these findings, it could be hypothesised that the processing environment could be a potential diffusion determinant of antibiotic resistant bacteria through the food chain and operators.}, } @article {pmid36118027, year = {2022}, author = {Amer, MA and Ramadan, MA and Attia, AS and Wasfi, R}, title = {Silicone Foley catheters impregnated with microbial indole derivatives inhibit crystalline biofilm formation by Proteus mirabilis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {1010625}, pmid = {36118027}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Catheters ; Humans ; Indoles/pharmacology ; Polyamines/pharmacology ; Polysaccharides/pharmacology ; *Proteus mirabilis ; Silicon/pharmacology ; Silicones/pharmacology ; }, abstract = {Proteus mirabilis is a common causative agent for catheter-associated urinary tract infections (CAUTI). The crystalline biofilm formation by P. mirabilis causes catheter encrustation and blockage leading to antibiotic treatment resistance. Thus, biofilm formation inhibition on catheters becomes a promising alternative for conventional antimicrobial-based treatment that is associated with rapid resistance development. Our previous work has demonstrated the in vitro antibiofilm activity of microbial indole derivatives against clinical isolates of P. mirabilis. Accordingly, we aim to evaluate the capacity of silicone Foley catheters (SFC) impregnated with these indole derivatives to resist biofilm formation by P. mirabilis both phenotypically and on the gene expression level. Silicon Foley catheter was impregnated with indole extract recovered from the supernatant of the rhizobacterium Enterobacter sp. Zch127 and the antibiofilm activity was determined against P. mirabilis (ATCC 12435) and clinical isolate P8 cultured in artificial urine. The indole extract at sub-minimum inhibitory concentration (sub-MIC=0.5X MIC) caused a reduction in biofilm formation as exhibited by a 60-70% reduction in biomass and three log10 in adhered bacteria. Results were confirmed by visualization by scanning electron microscope. Moreover, changes in the relative gene expression of the virulence genes confirmed the antibiofilm activity of the indole extract against P. mirabilis. Differential gene expression analysis showed that extract Zch127 at its sub-MIC concentration significantly down-regulated genes associated with swarming activity: umoC, flhC, flhD, flhDC, and mrpA (p< 0.001). In addition, Zch127 extract significantly down-regulated genes associated with polyamine synthesis: speB and glnA (p< 0.001), as well as the luxS gene associated with quorum sensing. Regulatory genes for capsular polysaccharide formation; rcsB and rcsD were not significantly affected by the presence of the indole derivatives. Furthermore, the impregnated catheters and the indole extract showed minimal or no cytotoxic effect against human fibroblast cell lines indicating the safety of this intervention. Thus, the indole-impregnated catheter is proposed to act as a suitable and safe strategy for reducing P. mirabilis CAUTIs.}, } @article {pmid36117726, year = {2022}, author = {Huang, K and Lin, B and Liu, Y and Ren, H and Guo, Q}, title = {Correlation Analysis between Chronic Osteomyelitis and Bacterial Biofilm.}, journal = {Stem cells international}, volume = {2022}, number = {}, pages = {9433847}, pmid = {36117726}, issn = {1687-966X}, abstract = {OBJECTIVE: To study the role of bacterial biofilm (BBF) in the formation of chronic osteomyelitis and its prevention and treatment.

METHODS: In this paper, a large amount of relevant literature was searched for analysis and summary, and the key words "chronic osteomyelitis," "bacterial biofilm," "infection," and "debridement" were searched in databases, mainly CNKI, Wanfang, and Wipu. The search was conducted until December 2020. The role of bacterial biofilm formation in chronic osteomyelitis and its prevention were analyzed.

RESULTS: Chronic osteomyelitis is formed mainly due to poor blood supply and drug-resistant bacteria, of which cellular biofilm is the most important cause. BBF forms on the surface of necrotic soft tissue and bone tissue, which has a protective effect on bacteria and greatly enhances their resistance to antibiotics, leading to difficulties in complete bacterial clearance and recurrent infections in osteomyelitis.

CONCLUSION: Through an in-depth study of the molecular biology and signal transduction of osteomyelitis biofilm, antibiotic biofilm treatment strategies and surgical debridement remain the focus of clinical translation of chronic osteomyelitis.}, } @article {pmid36117547, year = {2022}, author = {Eckert, JA and Rosenberg, M and Rhen, M and Choong, FX and Richter-Dahlfors, A}, title = {An optotracer-based antibiotic susceptibility test specifically targeting the biofilm lifestyle of Salmonella.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100083}, pmid = {36117547}, issn = {2590-2075}, abstract = {Antimicrobial resistance is a medical threat of global dimensions. Proper antimicrobial susceptibility testing (AST) for drug development, patient diagnosis and treatment is crucial to counteract ineffective drug use and resistance development. Despite the important role of bacterial biofilms in chronic and device-associated infections, the efficacy of antibiotics is determined using planktonic cultures. To address the need for antibiotics targeting bacteria in the biofilm lifestyle, we here present an optotracing-based biofilm-AST using Salmonella as model. Our non-disruptive method enables real-time recording of the extracellular matrix (ECM) components, providing specific detection of the biofilm lifestyle. Biofilm formation prior to antibiotic challenge can thus be confirmed and pre-treatment data collected. By introducing Kirby-Bauer discs, we performed a broad screen of the effects of antibiotics representing multiple classes, and identified compounds with ECM inhibitory as well as promoting effects. These compounds were further tested in agar-based dose-response biofilm-AST assays. By quantifying the ECM based on the amount of curli, and by visualizing the biofilm size and morphology, we achieved new information directly reflecting the treated biofilm. This verified the efficacy of several antibiotics that were effective in eradicating pre-formed biofilms, and it uncovered intriguing possible resistance mechanisms initiated in response to treatments. By providing deeper insights into the resistances and susceptibilities of microbes, expanded use of the biofilm-AST will contribute to more effective treatments of infections and reduced resistance development.}, } @article {pmid36116571, year = {2022}, author = {Zhang, W and Wu, Y and Wu, J and Zheng, X and Chen, Y}, title = {Enhanced removal of sulfur-containing organic pollutants from actual wastewater by biofilm reactor: Insights of sulfur transformation and bacterial metabolic traits.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {313}, number = {}, pages = {120187}, doi = {10.1016/j.envpol.2022.120187}, pmid = {36116571}, issn = {1873-6424}, mesh = {Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; Carbohydrates ; *Environmental Pollutants/metabolism ; Humans ; Nitrogen/metabolism ; Pyruvates/metabolism ; Sulfur ; Sulfur Compounds/metabolism ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Sulfur-containing organic pollutants in wastewater could threaten human health due to their high malodor and toxicity, and their conversion processes are more complex than inorganic sulfur compounds. Membrane aerated biofilm reactor (MABR), as a novel and environmentally-friendly biofilm-based technology, is able to remove inorganic sulfur in synthetic wastewater. However, it is unknown how sulfur-containing organic pollutants in actual wastewater are transformed in MABR system. This work demonstrated the feasibility of MABR to eliminate sulfur-containing organic pollutants in actual wastewater, and the removal efficiency could be reached at approximately 100%. Meanwhile, over 70% of sulfur-containing organic contaminants were transformed to SO4[2-] during the long-term operation. Further analysis indicated that the functional bacteria that participated in sulfur transformation and carbohydrates degradation (e.g., Chujaibacter, Microscillaceaesp., and Thiobacillus) were evidently enriched when treating actual wastewater. Moreover, the critical metabolic pathways (e.g., sulfur metabolism, glycolysis metabolism, and pyruvate metabolism), and the corresponding genetic expressions (e.g., nrrA, tauA, tauC, sorA, and SUOX) were evidently up-regulated during long-term operation, which was beneficial for the transformation of sulfur-containing organic pollutants in actual wastewater by MABR. This work would expand the application of MABR for treating the actual sulfur-containing organic wastewater and provide an in-depth understanding of the organic sulfur transformation in MABR.}, } @article {pmid36116146, year = {2022}, author = {Nie, LJ and Ye, WQ and Xie, WY and Zhou, WW}, title = {Biofilm: New insights in the biological control of fruits with Bacillus amyloliquefaciens B4.}, journal = {Microbiological research}, volume = {265}, number = {}, pages = {127196}, doi = {10.1016/j.micres.2022.127196}, pmid = {36116146}, issn = {1618-0623}, mesh = {Antifungal Agents/pharmacology ; *Bacillus amyloliquefaciens/genetics ; Biofilms ; Fruit/microbiology ; *Solanum lycopersicum ; }, abstract = {Biofilms are sessile microbial communities growing on surfaces, which are encased in some self-produced extracellular material. Beneficial biofilm could be widely used in agriculture, food, medicine, environment and other fields. As an ideal biocontrol agent, Bacillus amyloliquefaciens B4 can form a strong biofilm under static conditions. In this study, we screened out metal compounds that enhanced or inhibited the biofilm formation ability of B4, established the relationship between the biofilm of B4 strain and its postharvest biocontrol effect, and explored the regulation of metal compounds on the biofilm formation. The results showed 0.5 mmol L[-1] ferric chloride could enhance the biofilm formation and strengthen the antifungal effect of B4, indicating that there was a positive relationship between the growth of biofilm and its biocontrol effect. The enhanced biofilm had a certain biocontrol effect on different fruit, including peach, loquat, Kyoho grape and cherry tomato. Furthermore, the expression of degU and tasA was affected by metal ion treatment, which meant the genes might be essential for the biofilm formation of B4. Our findings suggested that biofilm of B. amyloliquefaciens played an essential role in the process of biocontrol and it might be a novel strategy for managing postharvest fruit decay.}, } @article {pmid36115405, year = {2023}, author = {Xie, T and Liu, X and Xu, Y and Bryson, S and Zhao, L and Huang, K and Huang, S and Li, X and Yang, Q and Dong, H and Winkler, MH}, title = {Coupling methanotrophic denitrification to anammox in a moving bed biofilm reactor for nitrogen removal under hypoxic conditions.}, journal = {The Science of the total environment}, volume = {856}, number = {Pt 1}, pages = {158795}, doi = {10.1016/j.scitotenv.2022.158795}, pmid = {36115405}, issn = {1879-1026}, mesh = {Denitrification ; Nitrogen/metabolism ; Biofilms ; Nitrates/metabolism ; Bioreactors/microbiology ; Anaerobiosis ; RNA, Ribosomal, 16S ; *Ammonium Compounds/metabolism ; Methane/metabolism ; *Methylococcaceae/metabolism ; Bacteria, Anaerobic/metabolism ; Bacteria/metabolism ; Oxidation-Reduction ; }, abstract = {Simultaneous removal of ammonium and nitrate was achieved in a methane-fed moving bed biofilm reactor (MBBR). In the reactor, methanotrophic microorganisms oxidized methane under hypoxic conditions likely to methanol, hence providing an electron donor to denitrifiers to reduce nitrate to nitrite that then allowed anaerobic ammonium oxidizing bacteria (Anammox) to remove excess ammonium as N2. The ammonium and nitrate removal rates reached 72.09 ± 5.81 mgNH4[+]-N/L/d and 62.61 ± 4.17 mgNO3[-]-N/L/d when the MBBR was operated in continuous mode. Nitrate removal by the methane-fed mixed consortia was confirmed in a batch test revealing a CH4/NO3[-] molar removal ratio of 1.15. The functional populations were unveiled by FISH analysis and 16S rRNA gene sequencing, which showed that the biofilm was dominated by Anammox bacteria (Candidatus Kuenenia) and diverse taxa associated with the capacity for denitrification: aerobic methanotrophs (Methylobacter, Methylomonas, and unclassified Methylococcaceae), methylotrophic denitrifiers (Opitutaceae and Methylophilaceae), and other heterotrophic denitrifiers (Ignavibacteriaceae, Anaerolineaceae, Comamonadaceae, Rhodocyclaceae and Thauera). Neither DAMO archaea nor DAMO bacteria were found in the sequencing analysis, indicating that more unknown community members possess the metabolic capacity of methanotrophic denitrification.}, } @article {pmid36114903, year = {2022}, author = {Harikrishnan, P and Arayambath, B and Jayaraman, VK and Ekambaram, K and Ahmed, EA and Senthilkumar, P and Ibrahim, HM and Sundaresan, A and Thirugnanasambantham, K}, title = {Thidiazuron, a phenyl-urea cytokinin, inhibits ergosterol synthesis and attenuates biofilm formation of Candida albicans.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {12}, pages = {224}, pmid = {36114903}, issn = {1573-0972}, mesh = {Acridine Orange/pharmacology ; Amino Acids/pharmacology ; *Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; Cytokinins ; Ergosterol/pharmacology ; Gentian Violet/pharmacology ; Humans ; Molecular Docking Simulation ; Phenylurea Compounds/pharmacology ; Thiadiazoles ; }, abstract = {Candida albicans is a common human fungal pathogen that colonizes mucosa and develops biofilm in the oral cavity that causes oral candidiasis. It has been reported that cytochrome P450 enzyme (CYP51), a vital part of the ergosterol synthesis cascade, is associated with Candida infections and its biofilm formation. Thidiazuron, a phenyl-urea cytokinin, exhibits anti-senescence and elicitor activity against fungal infection in plants. However, how Thidiazuron impacts C. albicans biofilm formation is still uncertain. Here, we aimed to investigate the effects of a Thidiazuron against the growth and biofilm formation properties of C. albicans using in silico and in vitro experimental approaches. A preliminary molecular docking study revealed potential interaction between Thidiazuron and amino acid residues of CYP51. Further in vitro antifungal susceptibility test, scanning electron microscopy (SEM) and time kill analysis revealed the anti-fungal activity of Thidiazuron in both dose and time-dependent manner. Crystal violet staining, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay revealed 50% inhibition in C. albicans biofilm by Thidiazuron at concentrations 11 and 19 µM respectively. Acridine orange staining assay visually confirmed the biofilm inhibitory potential of Thidiazuron. The gene expression study showed that Thidiazuron treatment down regulated the expression of genes involved in ergosterol synthesis (ERG3, ERG11, ERG25), cell adhesion (ASL3, EAP1), and hyphae development (EFG1, HWP1, SAP5) in C. albicans. Wherease, the expression of negative transcription regulator of hyphae (NRG1) was upregulated (5.7-fold) by Thidiazuron treatment. Collectively, our data suggest that Thidiazuron is a robust antifungal compound and an outstanding biofilm inhibitor, which may promise further therapeutic development due to CYP51 binding and inhibition of ergosterol formation against C. albicans.}, } @article {pmid36114754, year = {2022}, author = {Boltz, JP and Daigger, GT}, title = {A mobile-organic biofilm process for wastewater treatment.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {94}, number = {9}, pages = {e10792}, pmid = {36114754}, issn = {1554-7531}, mesh = {Biofilms ; Bioreactors ; Sewage ; *Wastewater ; *Water Purification/methods ; }, abstract = {The mobile-organic biofilm (MOB) process includes mobile biofilms and their retention screens with a bioreactor and liquid and solid separation. The MOB process is inexpensive and easy to integrate with wastewater treatment (WWT) processes, and it provides for high-rate WWT in biofilm or hybrid bioreactors. This paper describes three modes of MOB process operation. The first mode of operation, Mode I, has a mobile-biofilm reactor and a mobile-biofilm retention screen that is downstream of and external to a bioreactor and upstream of liquid and solid separation. Modes II and III have a hybrid (i.e., mobile biofilms and accumulated suspended biomass) bioreactor and liquid and solid separation. Mode II includes a mobile-biofilm retention screen that is downstream of and external to a hybrid bioreactor and upstream of liquid and solid separation. Mode III includes mobile-biofilm retention screening that is external to a hybrid bioreactor and liquid and solid separation, receives waste solids, and relies on environmental conditions and wastewater characteristics that are favorable for aerobic-granular sludge formation. This paper presents a mechanistic approach to design and evaluate MOB processes and describes MOB process: (1) modes of operation, (2) design and analysis methodology, (3) process and mechanical design criteria, (4) mathematical modeling, (5) design equations, and (6) mobile-biofilm settling characteristics and return. A mathematical model was applied to describe a fixed bioreactor volume and secondary-clarifier area with Modes I, II, and III. The mathematical modeling identified key differences between MOB process modes of operation, which are described in this paper. PRACTITIONER POINTS: MOB is a municipal and industrial wastewater treatment (WWT) process that reduces bioreactor and liquid and solids separation process volumes. It may operate with a mobile-biofilm reactor or a hybrid (mobile biofilms and suspended biomass) bioreactor. This paper provides a mechanistic basis for the selection and design of a MOB process mode of operation, and it describes MOB process modes of operation, design criteria, design equations, mathematical modeling, and mobile-biofilm settling characteristics. MOB integrated WWT plants exist at full scale and reliably meet their treatment objectives. The MOB process is an emerging environmental biotechnology for cost-effective WWT.}, } @article {pmid36113833, year = {2023}, author = {Keçeli Oğuz, S and Has, EG and Akçelik, N and Akçelik, M}, title = {Phenotypic impacts and genetic regulation characteristics of the DNA adenine methylase gene (dam) in Salmonella Typhimurium biofilm forms.}, journal = {Research in microbiology}, volume = {174}, number = {1-2}, pages = {103991}, doi = {10.1016/j.resmic.2022.103991}, pmid = {36113833}, issn = {1769-7123}, mesh = {Humans ; *Salmonella typhimurium/genetics/metabolism ; Site-Specific DNA-Methyltransferase (Adenine-Specific)/genetics/metabolism ; Caco-2 Cells ; Biofilms ; *MicroRNAs/metabolism ; Gene Expression Regulation, Bacterial ; Bacterial Proteins/genetics ; }, abstract = {In this study, transcriptional level gene expression changes in biofilm forms of Salmonella Typhimurium ATCC 14028 and its dam mutant were investigated by performing RNAseq analysis. As a result of these analyzes, a total of 233 differentially expressed genes (DEGs) were identified in the dam mutant, of which 145 genes were downregulated and 88 genes were upregulated compared to the wild type. According to data from miRNA sequence analysis, of 13 miRNAs differentially expressed in dam mutant, 9 miRNAs were downregulated and 4 miRNAs were upregulated. These data provide the first evidence that the dam gene is a global regulator of biofilm formation in Salmonella. In addition, phenotypic analyses revealed that bacterial swimming and swarming motility and cellulose production were highly inhibited in the dam mutant. It was determined that bacterial adhesion in Caco-2 and HEp-2 cell lines was significantly reduced in dam mutant. At the end of 90 min, the adhesion rate of wild type strain was 43.3% in Caco-2 cell line, while this rate was 14.9% in dam mutant. In the HEp-2 cell line, while 45.5% adherence was observed in the wild-type strain, this rate decreased to 15.3% in the dam mutant.}, } @article {pmid36111728, year = {2022}, author = {Gong, Y and Yin, S and Sun, S and Li, M}, title = {Chelerythrine reverses the drug resistance of resistant Candida albicans and the biofilm to fluconazole.}, journal = {Future microbiology}, volume = {17}, number = {}, pages = {1325-1333}, doi = {10.2217/fmb-2021-0203}, pmid = {36111728}, issn = {1746-0921}, mesh = {Antifungal Agents/pharmacology ; Benzophenanthridines ; Biofilms ; *Candida albicans ; Drug Resistance ; Drug Resistance, Fungal ; Drug Synergism ; *Fluconazole/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Aim: To evaluate the antifungal activity of chelerythrine in combination with fluconazole against planktonic Candida albicans strains and preformed biofilm. Materials & methods: A broth microdilution assay was used to reveal the antifungal activity of chelerythrine combined with fluconazole against C. albicans and the preformed biofilm. A fractional inhibitory concentration index model was used to evaluate the interaction. Results: Chelerythrine strongly synergized with fluconazole against fluconazole-resistant C. albicans and the biofilm preformed for less than 12 h. In addition, chelerythrine combined with fluconazole exhibited a synergistic effect against C. albicans morphogenesis. Conclusion: Chelerythrine could reverse the drug resistance of resistant C. albicans and its biofilm to fluconazole, providing new insights for overcoming the drug resistance of C. albicans.}, } @article {pmid36110822, year = {2022}, author = {Pawar, RO and Narote, PS and Gawai, KT and Amte, MP and Singh, S and Sonkesriya, S}, title = {Comparative Analysis of Biofilm Formation on Materials Used for the Fabrication of Implant Supported Prostheses.}, journal = {Journal of pharmacy & bioallied sciences}, volume = {14}, number = {Suppl 1}, pages = {S812-S815}, pmid = {36110822}, issn = {0976-4879}, abstract = {BACKGROUND: Zirconia and other dental pottery, heat-restored polymethyl methacrylate, titanium and other metal amalgams, or a mix of these materials are utilized to fix inserts. It is important to choose a material that is resistant to bacterial colonization for implant-supported prostheses, but durability and aesthetics are important factors as well.

AIM: Biofilm generation on materials used in implant-supported dental prosthesis manufacturing was an objective of this investigation.

METHODS AND MATERIALS: In this study, 90 discs were prepared. These discs were divided into three groups: group PMMA, group Y-TZP, and group CP-Ti. Each group consisted of 30 discs. As helpful materials, 30 discs (D = 15 mm, H = 3 mm) each were created from either monetarily unadulterated titanium (CP-Ti), yttria tetragonal zirconia polycrystal (YTZP), or hotness-restored polymethyl methacrylate (PMMA). The examples were cleaned as per acknowledged practices. The non-contact profilometer (NPFLEX, Bruker, UK) was utilized to survey the surface rougness of each disc, and the outcomes were accounted for as Ra (m). An assortment of gram-negative microbes, including Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella albicans, were refined close by cleaned discs produced using heat-relieved PMMA, Y-TZP, or CP-Ti to see which type of biofilm is shaped best. CFU/mL was the unit of estimation (state framing units per milliliter).

RESULTS: Y-TZP discs have a substantially higher Ra (349 41 m) than PMMA and CP-Ti discs. Some bacteria that have been associated with peri-mucositis and peri-implantitis may be less prevalent on Y-TZP or CP-Ti discs. Biofilm development must be considered while making implant-supported prostheses using Y-TZP and CP-Ti.

CONCLUSION: Y-TZP and CP-Ti are preferred materials for implant-supported prosthesis production because of biofilm development.}, } @article {pmid36110744, year = {2022}, author = {Vaddamanu, SK and Vyas, R and Kavita, K and Sushma, R and Rani, RP and Dixit, A and Badiyani, BK}, title = {An In Vitro study to Compare Dental Laser with other Treatment Modalities on Biofilm Ablation from Implant and Tooth Surfaces.}, journal = {Journal of pharmacy & bioallied sciences}, volume = {14}, number = {Suppl 1}, pages = {S530-S533}, pmid = {36110744}, issn = {0976-4879}, abstract = {BACKGROUND: Periodontal and peri-implant disorders are etiologically linked to bacterial biofilms. The researchers wanted to see how well the erbium-doped yttrium aluminum garnet (Er:YAG) laser removed bacterial biofilms along with attached epithelial cells (EC), gingival fibroblasts (GF), in addition to osteoblast-like cells (OC) dentin along with titanium surfaces compared to previous therapy methods.

METHODOLOGY: 3.5 days were spent growing bacterial biofilms on standardized dentin and also titanium samplings using a sand-blasted along with the acid-etched surface. Following that, the specimens were positioned into pockets that had been formed artificially. The following approaches were used to remove biofilm: (1) Er:YAG, (2) photodynamic therapy (PDT), and (3) curette (CUR) along with supplementary PDT (CUR/PDT). The remaining biofilms' colony forming units (CFUs) were determined, as well as the attachment of EC, GF, in addition to OC. Analysis of variance with a posthoc least significant difference was utilized in the statistical analysis.

RESULTS: When compared to untreated dentin and titanium surfaces, all therapy strategies reduced total CFUs in statistically significant biofilms (p = 0.001). On the dentin, Er:YAG was as effective as CUR and PDT, but not as effective as CUR/PDT (p = 0.005). The application of Er:YAG on titanium surfaces leads to statistically significantly improved biofilm eradication equated to the supplementary three therapies (all p = 0.001). On untouched infested dentin and titanium surfaces, the counts of attached EC, GF, and OC were the lowermost. Atop the dentin, increased EC counts were detected after CUR/PDT (p = 0.006). On titanium, all cleaning procedures increased the counts of attached EC by a statistically significant amount (p = 0.001), with no variations between groups. After Er:YAG decontamination, there were statistically substantially elevated amounts of GF (p = 0.024) and OC (p = 0.001) than on untreated surfaces.

CONCLUSION: The usage of Er:YAG laser to ablate subgingival biofilms and, specifically, to decontaminate titanium implant surfaces appears to be a promising strategy that needs further research.}, } @article {pmid36110706, year = {2022}, author = {Pawar, M and Agwan, MAS and Toshniwal, NG and Biswas, K and Raina, R and Pawar, S}, title = {Efficacy of Ozone to Eliminate Endopathogenic Microorganism in Rootcanal Biofilm.}, journal = {Journal of pharmacy & bioallied sciences}, volume = {14}, number = {Suppl 1}, pages = {S876-S879}, pmid = {36110706}, issn = {0976-4879}, abstract = {OBJECTIVE: The researchers wanted to see whether ozonated water with ultrasonication and sodium hypochlorite can destroy Enterococcus faecalis bacteria in root canals.

MATERIALS AND METHODS: A total of 40 single-rooted human teeth were used. A total of 100 roots were harvested and mechanically prepared. The root canals were randomly divided into four classes (n = 10) after being infected with E. faecalis for 24 h. Each sample's MTT value was calculated.

CONCLUSIONS: NaOCl and aqueous ozone provide antibacterial effects in in-vitro conditions in root canals.}, } @article {pmid36110303, year = {2022}, author = {Zhang, D and Shen, J and Peng, X and Gao, S and Wang, Z and Zhang, H and Sun, W and Niu, H and Ying, H and Zhu, C and Chen, Y and Liu, D}, title = {Physiological changes and growth behavior of Corynebacterium glutamicum cells in biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {983545}, pmid = {36110303}, issn = {1664-302X}, abstract = {Biofilm cells are well-known for their increased survival and metabolic capabilities and have been increasingly implemented in industrial and biotechnological processes. Corynebacterium glutamicum is one of the most widely used microorganisms in the fermentation industry. However, C. glutamicum biofilm has been rarely reported and little is known about its cellular basis. Here, the physiological changes and characteristics of C. glutamicum biofilm cells during long-term fermentation were studied for the first time. Results showed that the biofilm cells maintained stable metabolic activity and cell size was enlarged after repeated-batch of fermentation. Cell division was slowed, and chromosome content and cell proliferation efficiency were reduced during long-term fermentation. Compared to free cells, more biofilm cells were stained by the apoptosis indicator dyes Annexin V-FITC and propidium iodide (PI). Overall, these results suggested slow-growing, long-lived cells of C. glutamicum biofilm during fermentation, which could have important industrial implications. This study presents first insights into the physiological changes and growth behavior of C. glutamicum biofilm cell population, which would be valuable for understanding and developing biofilm-based processes.}, } @article {pmid36109038, year = {2022}, author = {Tillander, JAN and Rilby, K and Svensson Malchau, K and Skovbjerg, S and Lindberg, E and Rolfson, O and Trobos, M}, title = {Treatment of periprosthetic joint infections guided by minimum biofilm eradication concentration (MBEC) in addition to minimum inhibitory concentration (MIC): protocol for a prospective randomised clinical trial.}, journal = {BMJ open}, volume = {12}, number = {9}, pages = {e058168}, pmid = {36109038}, issn = {2044-6055}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; *Arthritis, Infectious ; Biofilms ; Humans ; Microbial Sensitivity Tests ; Prospective Studies ; Randomized Controlled Trials as Topic ; }, abstract = {INTRODUCTION: Prosthetic joint infections (PJIs) are disastrous complications for patients and costly for healthcare organisations. They may promote bacterial resistance due to the extensive antibiotic use necessary in the PJI treatment. The PJI incidence is estimated to be 1%-3%, but the absolute numbers worldwide are high and increasing as large joint arthroplasties are performed by the millions each year. Current treatment algorithms, based on implant preserving surgery or full revision followed by a semitailored antibiotic regimen for no less than 2-3 months, lead to infection resolution in approximately 60% and 90%, respectively. Antibiotic choice is currently guided by minimum inhibitory concentrations (MICs) of free-living bacteria and not of bacteria in biofilm growth mode. Biofilm assays with relatively rapid output for the determination of minimum biofilm eradication concentrations (MBECs) have previously been developed but their clinical usefulness have not been established.

METHODS AND ANALYSIS: This single-blinded, two-arm randomised study of hip or knee staphylococcal PJI will evaluate 6-week standard of care (MIC guided), or an alternative antibiotic regimen according to an MBEC-guided-based decision algorithm. Sixty-four patients with a first-time PJI treated according to the debridement, antibiotics, and implant retention principle will be enrolled at a single tertiary orthopaedic centre (Sahlgrenska University Hospital). Patients will receive 14 days of standard parenteral antibiotics before entering the comparative study arms. The primary outcome measurement is the proportion of changes in antimicrobial regimen from first-line treatment dependent on randomisation arm. Secondary endpoints are unresolved infection, how microbial properties including biofilm abilities and emerging antimicrobial resistance correlate to infection outcomes, patient reported outcomes and costs with a 12-month follow-up.

ETHICS AND DISSEMINATION: Approval is received from the Swedish Ethical Review Authority, no 2020-01471 and the Swedish Medical Products Agency, EudraCT, no 2020-003444-80.

TRIAL REGISTRATION NUMBER: ClinicalTrials.gov ID: NCT04488458.}, } @article {pmid36107719, year = {2022}, author = {Stepanov, D and Buchmann, D and Schultze, N and Wolber, G and Schaufler, K and Guenther, S and Belik, V}, title = {A Combined Bayesian and Similarity-Based Approach for Predicting E. coli Biofilm Inhibition by Phenolic Natural Compounds.}, journal = {Journal of natural products}, volume = {85}, number = {10}, pages = {2255-2265}, doi = {10.1021/acs.jnatprod.2c00005}, pmid = {36107719}, issn = {1520-6025}, mesh = {*Escherichia coli ; Bayes Theorem ; *Biofilms ; Phenols/pharmacology ; }, abstract = {Screening for biofilm inhibition by purified natural compounds is difficult due to compounds' chemical diversity and limited commercial availability, combined with time- and cost-intensiveness of the laboratory process. In silico prediction of chemical and biological properties of molecules is a widely used technique when experimental data availability is of concern. At the same time, the performance of predictive models directly depends on the amount and quality of experimental data. Driven by the interest in developing a model for prediction of the antibiofilm effect of phenolic natural compounds such as flavonoids, we performed experimental assessment of antibiofilm activity of 320 compounds from this subset of chemicals. The assay was performed once on two Escherichia coli strains on agar in 24-well microtiter plates. The inhibition was assessed visually by detecting morphological changes in macrocolonies. Using the data obtained, we subsequently trained a Bayesian logistic regression model for prediction of biofilm inhibition, which was combined with a similarity-based method in order to increase the overall sensitivity (at the cost of accuracy). The quality of the predictions was subsequently validated by experimental assessment in three independent experiments with two resistant E. coli strains of 23 compounds absent in the initial data set. The validation demonstrated that the model may successfully predict the targeted effect as compared to the baseline accuracy. Using a randomly selected database of commercially available natural phenolics, we obtained approximately 6.0% of active compounds, whereas using our prediction-based substance selection, the percentage of phenolics found to be active increased to 34.8%.}, } @article {pmid36104421, year = {2022}, author = {Rumbaugh, KP}, title = {Dispersing biofilm myths.}, journal = {Nature reviews. Microbiology}, volume = {20}, number = {10}, pages = {573-574}, pmid = {36104421}, issn = {1740-1534}, mesh = {*Biofilms ; *Pseudomonas aeruginosa ; }, } @article {pmid36103517, year = {2022}, author = {Blaskovich, MAT and Hansford, KA and Butler, MS and Ramu, S and Kavanagh, AM and Jarrad, AM and Prasetyoputri, A and Pitt, ME and Huang, JX and Lindahl, F and Ziora, ZM and Bradford, T and Muldoon, C and Rajaratnam, P and Pelingon, R and Edwards, DJ and Zhang, B and Amado, M and Elliott, AG and Zuegg, J and Coin, L and Woischnig, AK and Khanna, N and Breidenstein, E and Stincone, A and Mason, C and Khan, N and Cho, HK and Karau, MJ and Greenwood-Quaintance, KE and Patel, R and Wootton, M and James, ML and Hutton, ML and Lyras, D and Ogunniyi, AD and Mahdi, LK and Trott, DJ and Wu, X and Niles, S and Lewis, K and Smith, JR and Barber, KE and Yim, J and Rice, SA and Rybak, MJ and Ishmael, CR and Hori, KR and Bernthal, NM and Francis, KP and Roberts, JA and Paterson, DL and Cooper, MA}, title = {A lipoglycopeptide antibiotic for Gram-positive biofilm-related infections.}, journal = {Science translational medicine}, volume = {14}, number = {662}, pages = {eabj2381}, doi = {10.1126/scitranslmed.abj2381}, pmid = {36103517}, issn = {1946-6242}, support = {094977/Z/10/Z/WT_/Wellcome Trust/United Kingdom ; R01 AI152210/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology ; Biofilms ; Glycopeptides/pharmacology/therapeutic use ; *Gram-Positive Bacterial Infections ; Lipoglycopeptides/therapeutic use ; Mammals ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; Microbial Sensitivity Tests ; Streptococcus pneumoniae ; Vancomycin/pharmacology/therapeutic use ; }, abstract = {Drug-resistant Gram-positive bacterial infections are still a substantial burden on the public health system, with two bacteria (Staphylococcus aureus and Streptococcus pneumoniae) accounting for over 1.5 million drug-resistant infections in the United States alone in 2017. In 2019, 250,000 deaths were attributed to these pathogens globally. We have developed a preclinical glycopeptide antibiotic, MCC5145, that has excellent potency (MIC90 ≤ 0.06 μg/ml) against hundreds of isolates of methicillin-resistant S. aureus (MRSA) and other Gram-positive bacteria, with a greater than 1000-fold margin over mammalian cell cytotoxicity values. The antibiotic has therapeutic in vivo efficacy when dosed subcutaneously in multiple murine models of established bacterial infections, including thigh infection with MRSA and blood septicemia with S. pneumoniae, as well as when dosed orally in an antibiotic-induced Clostridioides difficile infection model. MCC5145 exhibited reduced nephrotoxicity at microbiologically active doses in mice compared to vancomycin. MCC5145 also showed improved activity against biofilms compared to vancomycin, both in vitro and in vivo, and a low propensity to select for drug resistance. Characterization of drug action using a transposon library bioinformatic platform showed a mechanistic distinction from other glycopeptide antibiotics.}, } @article {pmid36103515, year = {2022}, author = {Powell, LC and Cullen, JK and Boyle, GM and De Ridder, T and Yap, PY and Xue, W and Pierce, CJ and Pritchard, MF and Menzies, GE and Abdulkarim, M and Adams, JYM and Stokniene, J and Francis, LW and Gumbleton, M and Johns, J and Hill, KE and Jones, AV and Parsons, PG and Reddell, P and Thomas, DW}, title = {Topical, immunomodulatory epoxy-tiglianes induce biofilm disruption and healing in acute and chronic skin wounds.}, journal = {Science translational medicine}, volume = {14}, number = {662}, pages = {eabn3758}, doi = {10.1126/scitranslmed.abn3758}, pmid = {36103515}, issn = {1946-6242}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cattle ; Humans ; Keratinocytes ; Mice ; *Phorbols ; Wound Healing ; }, abstract = {The management of antibiotic-resistant, bacterial biofilm infections in chronic skin wounds is an increasing clinical challenge. Despite advances in diagnosis, many patients do not derive benefit from current anti-infective/antibiotic therapies. Here, we report a novel class of naturally occurring and semisynthetic epoxy-tiglianes, derived from the Queensland blushwood tree (Fontainea picrosperma), and demonstrate their antimicrobial activity (modifying bacterial growth and inducing biofilm disruption), with structure/activity relationships established against important human pathogens. In vitro, the lead candidate EBC-1013 stimulated protein kinase C (PKC)-dependent neutrophil reactive oxygen species (ROS) induction and NETosis and increased expression of wound healing-associated cytokines, chemokines, and antimicrobial peptides in keratinocytes and fibroblasts. In vivo, topical EBC-1013 induced rapid resolution of infection with increased matrix remodeling in acute thermal injuries in calves. In chronically infected diabetic mouse wounds, treatment induced cytokine/chemokine production, inflammatory cell recruitment, and complete healing (in six of seven wounds) with ordered keratinocyte differentiation. These results highlight a nonantibiotic approach involving contrasting, orthogonal mechanisms of action combining targeted biofilm disruption and innate immune induction in the treatment of chronic wounds.}, } @article {pmid36102939, year = {2023}, author = {Dishan, A and Hizlisoy, H and Barel, M and Disli, HB and Gungor, C and Ertas Onmaz, N and Gonulalan, Z and Al, S and Yildirim, Y}, title = {Biofilm formation, antibiotic resistance and genotyping of Shiga toxin-producing Escherichia coli isolated from retail chicken meats.}, journal = {British poultry science}, volume = {64}, number = {1}, pages = {63-73}, doi = {10.1080/00071668.2022.2116697}, pmid = {36102939}, issn = {1466-1799}, mesh = {Animals ; *Shiga-Toxigenic Escherichia coli/genetics ; Chickens/genetics ; Genotype ; RNA, Ribosomal, 16S ; *Escherichia coli Proteins/genetics ; Drug Resistance, Microbial ; *Escherichia coli O157/genetics ; Meat/microbiology ; Biofilms ; }, abstract = {1. The Shiga toxin-producing Escherichia coli (STEC) is a hazardous zoonotic agent for chicken meat consumers. This study determined the serogroups and evaluated the virulence genes, antibiotic resistance, biofilm-forming profiles and genetic relationships of STEC isolates in chicken meat.2. A total of 100 samples belonging to dressed-whole chicken and different parts of the chicken (wing, breast, thigh, drumstick) were collected between September and November 2019 from different retail markets in Kayseri, Türkiye.3. Phenotypic (identification, disc diffusion test, Congo red agar and microtitre plate tests) and molecular tests (identification, serogrouping, virulence factors, biofilm, antibiotic susceptibility, 16S rRNA sequencing and enterobacterial repetitive intergenic consensus-PCR for typing of the isolates) were carried out.4. E. coli was isolated from 35% of the samples and 35% of the samples harboured at least one STEC. Among 35 STEC isolates, 3 (8.5%), 6 (17.1%), 2 (5.7%) and 3 (8.5%) were found to be positive for fliCH2, fliCH8, fliCH11, fliCH19 genes, respectively. Out of 35 STEC positive isolates, 4 (11.4%) were identified as E. coli O157, from which 2 (5.7%) were E. coli O157:H7. E. coli O157 was detected in two (10%), one (5%), one (5%) of the thigh, drumstick and whole chicken samples, respectively.5. Biofilm-forming ability was reported in 33 (94.2%) of 35 E. coli isolates, whilst the biofilm-associated genes detected among 35 STEC isolates included csgA (88.5%), fimH (88.5%), bcsA (85.7%), agn43 (14.2%) and papC (8.5%). The STEC strains showed resistance against ampicillin (88.5%) and erythromycin (88.5%), followed by tetracycline (74.2%) and gentamicin (25.7%). However, the distribution of isolates harbouring blaCMY, ere(A), tet(A) and aac(3)-IV antibiotic resistance genes was found to be 17.1%, 11.4%, 85.7% and 5.7%, respectively.6. ERIC-PCR showed that E. coli strains obtained from different parts and whole of chicken samples had genetic diversities. ERIC-PCR patterns grouped strains of 35 STEC into eight clusters designated A-H, with 73% similarity. Proper hygiene measures and staff training are essential for public health during poultry processing and in retail stores to control STEC.}, } @article {pmid36102678, year = {2022}, author = {Wang, Y and Li, C and Wang, J and Bai, N and Zhang, H and Chi, Y and Cai, Y}, title = {The Efficacy of Colistin Combined with Amikacin or Levofloxacin against Pseudomonas aeruginosa Biofilm Infection.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0146822}, pmid = {36102678}, issn = {2165-0497}, mesh = {Mice ; Animals ; *Colistin/pharmacology/therapeutic use ; Amikacin/pharmacology/therapeutic use ; Levofloxacin/pharmacology/therapeutic use ; Pseudomonas aeruginosa ; Meropenem/pharmacology/therapeutic use ; Drug Resistance, Multiple, Bacterial ; *Pseudomonas Infections/drug therapy/microbiology ; Biofilms ; Anti-Bacterial Agents/therapeutic use ; Microbial Sensitivity Tests ; Carbapenems/therapeutic use ; Drug Combinations ; }, abstract = {Pseudomonas aeruginosa (PA) biofilm infection is clinically prevalent and difficult to eradicate. In the present work, we aimed to evaluate the in vitro and in vivo efficacy of colistin (COL)-based combinations against PA biofilm. MICs and fractional inhibitory concentration indexes (FICIs) of four antibiotics (COL, amikacin, levofloxacin, and meropenem) to bioluminescent strain PAO1, carbapenem-resistant PAO1 (CRPAO1), and clinically isolated strains were assessed. Minimal biofilm eradication concentrations (MBECs) of monotherapy and combinations were examined by counting the live bacteria in biofilm, accompanied by visual confirmation using confocal laser-scanning microscopy. An animal biofilm infection model was established by implanting biofilm subcutaneously, and the therapeutic effect was evaluated according to the change in luminescence through a live animal bio-photonic imaging system. In vitro, even combined with 4 or 8 mg/L COL, meropenem needed to reach 128 or 256 mg/L to eradicate the biofilm. Moreover, 2 mg/L COL combined with 32 mg/L amikacin or 4-8 mg/L levofloxacin could kill the PAO1 and CRPAO1 in biofilm within 24 h. In vivo, COL combined with amikacin or levofloxacin could shorten the eradication time of biofilm than monotherapy. For PAO1 biofilm, combination therapy could eradicate the biofilm in all mice on the 5th day, whereas monotherapy only eradicated biofilms in almost half of the mice. For CRPAO1 biofilm, the biofilm eradication rate on the 6th day in the COL+ amikacin, amikacin, or COL alone regimen was 90%, 10%, or 40%, respectively. COL combined with levofloxacin did not show a better effect than each individual antibiotic. COL-based combinations containing levofloxacin or amikacin were promising choices for treating PA biofilm infection. IMPORTANCE Infections associated with PA biofilm formation are extremely challenging. When monotherapy fails to achieve optimal efficacy, combination therapy becomes the last option. After evaluating multiple drug combinations through a series of experiments in vitro and in vivo, we confirmed that colistin-based combinations containing levofloxacin or amikacin were promising choices for treating PA biofilm infection. The efficacy of these combinations derives from the different bactericidal mechanisms and the bacterial susceptibility to each antibiotic. This study provided a new regimen to solve the incurable problem of biofilm by using COL combined with other antibiotics.}, } @article {pmid36101330, year = {2022}, author = {Ballah, FM and Islam, MS and Rana, ML and Ferdous, FB and Ahmed, R and Pramanik, PK and Karmoker, J and Ievy, S and Sobur, MA and Siddique, MP and Khatun, MM and Rahman, M and Rahman, MT}, title = {Phenotypic and Genotypic Detection of Biofilm-Forming Staphylococcus aureus from Different Food Sources in Bangladesh.}, journal = {Biology}, volume = {11}, number = {7}, pages = {}, pmid = {36101330}, issn = {2079-7737}, support = {TETFund/2020//Tertiary Education Trust Fund, Nigeria/ ; 2019/8/BAU//Bangladesh Agricultural University Research System (BAURES)/ ; }, abstract = {Staphylococcus aureus is a major foodborne pathogen. The ability of S. aureus to produce biofilm is a significant virulence factor, triggering its persistence in hostile environments. In this study, we screened a total of 420 different food samples and human hand swabs to detect S. aureus and to determine their biofilm formation ability. Samples analyzed were meat, milk, eggs, fish, fast foods, and hand swabs. S. aureus were detected by culturing, staining, biochemical, and PCR. Biofilm formation ability was determined by Congo Red Agar (CRA) plate and Crystal Violet Microtiter Plate (CVMP) tests. The icaA, icaB, icaC, icaD, and bap genes involved in the synthesis of biofilm-forming intracellular adhesion compounds were detected by PCR. About 23.81% (100/420; 95% CI: 14.17−29.98%) of the samples harbored S. aureus, as revealed by detection of the nuc gene. The CRA plate test revealed 20% of S. aureus isolates as strong biofilm producers and 69% and 11% as intermediate and non-biofilm producers, respectively. By the CVMP staining method, 20%, 77%, and 3% of the isolates were found to be strong, intermediate, and non-biofilm producers. Furthermore, 21% of S. aureus isolates carried at least one biofilm-forming gene, where icaA, icaB, icaC, icaD, and bap genes were detected in 15%, 20%, 7%, 20%, and 10% of the S. aureus isolates, respectively. Bivariate analysis showed highly significant correlations (p < 0.001) between any of the two adhesion genes of S. aureus isolates. To the best of our knowledge, this is the first study in Bangladesh describing the detection of biofilm-forming S. aureus from foods and hand swabs using molecular-based evidence. Our findings suggest that food samples should be deemed a potential reservoir of biofilm-forming S. aureus, which indicates a potential public health significance.}, } @article {pmid36099989, year = {2022}, author = {Akao, PK and Kaplan, A and Avisar, D and Dhir, A and Avni, A and Mamane, H}, title = {Removal of carbamazepine, venlafaxine and iohexol from wastewater effluent using coupled microalgal-bacterial biofilm.}, journal = {Chemosphere}, volume = {308}, number = {Pt 2}, pages = {136399}, doi = {10.1016/j.chemosphere.2022.136399}, pmid = {36099989}, issn = {1879-1298}, mesh = {Ammonia ; Bacteria ; Biofilms ; Carbamazepine ; Chlorophyll ; Iohexol ; *Microalgae ; Oxygen ; Pharmaceutical Preparations ; Venlafaxine Hydrochloride ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {We evaluated the removal capacity of a coupled microalgal-bacterial biofilm (CMBB) to eliminate three recalcitrant pharmaceuticals. The CMBB's efficiency, operating at different biofilm concentrations, with or without light, was compared and analyzed to correlate these parameters to pharmaceutical removal and their effect on the microorganism community. Removal rates changed with changing pharmaceutical and biofilm concentrations: higher biofilm concentrations presented higher removal. Removal of 82-94% venlafaxine and 18-51% carbamazepine was obtained with 5 days of CMBB treatment. No iohexol removal was observed. Light, microorganism composition, and dissolved oxygen concentration are essential parameters governing the removal of pharmaceuticals and ammonia. Chlorophyll concentration increased with time, even in the dark. Three bacterial phyla were dominant: Proteobacteria, Bacteroidetes and Firmicutes. The dominant eukaryotic supergroups were Archaeplastida, Excavata and SAR. A study of the microorganisms' community indicated that not only do the species in the biofilm play an important role; environment, concentration and interactions among them are also important. CMBB has the potential to provide low-cost and sustainable treatment for wastewater and recalcitrant pharmaceutical removal. The microenvironments on the biofilm created by the microalgae and bacteria improved treatment efficiency.}, } @article {pmid36099875, year = {2022}, author = {Mohd Badri, PEA and Rismayuddin, NAR and Kenali, NM and Darnis, DS and Arzmi, MH}, title = {Characterization of Cervus timorensis velvet antler and its effect on biofilm formation of Candida species.}, journal = {Medical mycology}, volume = {60}, number = {9}, pages = {}, doi = {10.1093/mmy/myac073}, pmid = {36099875}, issn = {1460-2709}, support = {FRGS/1/2019/SKK14/UIAM/03/4//Ministry of Higher Education, Malaysia/ ; RMCG20-043-0043//International Islamic University Malaysia/ ; //University of Melbourne/ ; }, mesh = {Animals ; *Antlers ; Biofilms ; Candida ; Candida glabrata ; Candida tropicalis ; *Deer ; Plant Extracts/pharmacology ; }, abstract = {Oral biofilms comprise extracellular polysaccharides and polymicrobial microorganisms. The objectives of the study were to characterize the deer velvet antler (DVA) compounds and their effect on Candida species biofilm formation with the hypothesis that DVA inhibits the biofilm of Candida spp. Liquid Chromatography-Quadrupole Time of Flight-Mass Spectrometry (LC-QTOF-MS) was conducted to characterize the DVA compounds. To study the effect of DVA on biofilm, Candida albicans ATCC MYA-4901 (ALT5), AIDS isolate (ALC2), oral cancer isolate (ALC3), C. dubliniensis ATCC MYA-2975, C. glabrata ATCC 90030, C. krusei 14 243, C. lusitaniae ATCC 34449, C. parapsilosis ATCC 22019, and C. tropicalis ATCC 13803 were inoculated with DVA in separate wells of a 96-well plate containing RPMI-1640 followed by 72 h incubation. A total of 45 compounds were detected in the DVA extract. C. lusitaniae exhibited a higher percentage of biofilm biomass reduction when treated with DVA extract (66.10% ± 5.33), followed by ALC3 (44.12% ± 6.24). However, C. glabrata, C. krusei, and C. parapsilosis showed no reduction in biofilm biomass after being treated with DVA extract. Most Candida strains also exhibited decreased total cell count when treated with DVA extract, except for ALC3 and C. krusei. ALT5 had the lowest total cell count (0.17 × 105 cells/ml) when cultured with DVA extract. In conclusion, DVA extract inhibits Candida spp. biofilm formation except for C. glabrata, C. krusei, and C. parapsilosis.}, } @article {pmid36098931, year = {2023}, author = {Vanajothi, R and Bhavaniramya, S and Vijayakumar, R and Alothaim, AS and Alqurashi, YE and Vishnupriya, S and Vaseeharan, B and Umadevi, M}, title = {In silico and In vitro Analysis of Nigella sativa Bioactives Against Chorismate Synthase of Listeria monocytogenes: a Target Protein for Biofilm Inhibition.}, journal = {Applied biochemistry and biotechnology}, volume = {195}, number = {1}, pages = {519-533}, pmid = {36098931}, issn = {1559-0291}, mesh = {Humans ; *Listeria monocytogenes/metabolism ; *Nigella sativa ; Molecular Docking Simulation ; Biofilms ; }, abstract = {Listeria monocytogenes have the ability to form biofilms, which aid in the contamination of food and the evasion of antimicrobials. Consumption of L. monocytogenes laden food can promote mild to severe infection in humans and cause serious health issues. Therefore, biofilm development by L. monocytogenes is considered to be a major concern for both healthcare and food safety. This study attempted to target chorismate synthase, an essential protein predicted to be involved in the biofilm pathway. Nigella sativa is renowned for its applications in folk medicine; hence, bioactive ingredients reported were used for molecular docking studies. In the absence of a three-dimensional structure of chorismate synthase from L. monocytogenes, a homology model was generated using the Modeller program. A model with the highest DOPE score was chosen and validated. The reliable model was subjected to docking studies with 30 ligands from N. sativa. From this approach, α-longipinene was unveiled as the best hit. Further in vitro studies demonstrated the antibiofilm potential of α-longipinene against L. monocytogenes. Overall, the study reveals lead molecules from N. sativa as promising antibiofilm agents against L. monocytogenes. Hence, extended investigation with lead molecules will provide sustainable strategies to prevent biofilm-mediated problems due to L. monocytogenes.}, } @article {pmid36098923, year = {2023}, author = {Miyagi, K and Shimoji, N and Oshiro, H and Hirai, I}, title = {Differences in flaA gene sequences, swimming motility, and biofilm forming ability between clinical and environmental isolates of Aeromonas species.}, journal = {Environmental science and pollution research international}, volume = {30}, number = {5}, pages = {11740-11754}, pmid = {36098923}, issn = {1614-7499}, mesh = {*Aeromonas/genetics ; Flagellin/genetics/metabolism ; Swimming ; Phylogeny ; Biofilms ; }, abstract = {The flagellin A gene (flaA) sequences, swimming motility, and biofilm forming ability were investigated in order to reveal the genetic and functional differences of flagella between clinical and environmental isolates of Aeromonas species. Twenty-eight clinical and 48 environmental strains of Aeromonas species isolated in Okinawa Prefecture of Japan were used in this study. The full-length flaA genes of these strains were sequenced and aligned, and a phylogenetic tree was constructed. In addition, swimming motility and biofilm forming ability were evaluated by conventional methods. Aeromonas veronii biovar sobria and A. hydrophila clearly divided into clinical and environmental strain clusters in the flaA phylogenetic classification, and the six and 13 specific amino acids respectively, of FlaA of both species were different in clinical and environmental strains. Furthermore, the flaA size of the clinical strain of A. veronii bv. sobria was mainly 909, 924, and 939 bp, and the size of A. hydrophila was 909 bp. The swimming motility of clinical isolates of both species was lower than the environmental isolates; however, the biofilm forming ability of the clinical isolates was high. Thus, the clinical isolates of A. veronii bv. sobria and A. hydrophila had different genetic and functional characteristics of flagellin than the environmental isolates. The characteristics of flagellin could serve as indicators to distinguish between clinical and environmental isolates of the both species. It may contribute to diagnosis of these diseases and the monitoring of clinical strain invasion into the natural environment.}, } @article {pmid36098534, year = {2022}, author = {Sherlock, D and Fogg, PCM}, title = {Loss of the Rhodobacter capsulatus Serine Acetyl Transferase Gene, cysE1, Impairs Gene Transfer by Gene Transfer Agents and Biofilm Phenotypes.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {19}, pages = {e0094422}, pmid = {36098534}, issn = {1098-5336}, support = {/WT_/Wellcome Trust/United Kingdom ; 109363/Z/15/A/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Biofilms ; Cysteine/metabolism ; DNA/metabolism ; Gene Expression Regulation, Bacterial ; Gene Transfer, Horizontal ; Phenotype ; *Rhodobacter capsulatus/genetics ; Serine ; Serine O-Acetyltransferase/genetics/metabolism ; }, abstract = {Biofilms are widespread in the environment, where they allow bacterial species to survive adverse conditions. Cells in biofilms are densely packed, and this proximity is likely to increase the frequency of horizontal gene transfer. Gene transfer agents (GTAs) are domesticated viruses with the potential to spread any gene between bacteria. GTA production is normally restricted to a small subpopulation of bacteria, and regulation of GTA loci is highly coordinated, but the environmental conditions that favor GTA production are poorly understood. Here, we identified a serine acetyltransferase gene, cysE1, in Rhodobacter capsulatus that is required for optimal receipt of GTA DNA, accumulation of extracellular polysaccharide, and biofilm formation. The cysE1 gene is directly downstream of the core Rhodobacter-like GTA (RcGTA) structural gene cluster and upregulated in an RcGTA overproducer strain, although it is expressed on a separate transcript. The data we present suggest that GTA production and biofilm are coregulated, which could have important implications for the study of rapid bacterial evolution and understanding the full impact of GTAs in the environment. IMPORTANCE Direct exchange of genes between bacteria leads to rapid evolution and is the major factor underlying the spread of antibiotic resistance. Gene transfer agents (GTAs) are an unusual but understudied mechanism for genetic exchange that are capable of transferring any gene from one bacterium to another, and therefore, GTAs are likely to be important factors in genome plasticity in the environment. Despite the potential impact of GTAs, our knowledge of their regulation is incomplete. In this paper, we present evidence that elements of the cysteine biosynthesis pathway are involved in coregulation of various phenotypes required for optimal biofilm formation by Rhodobacter capsulatus and successful infection by the archetypal RcGTA. Establishing the regulatory mechanisms controlling GTA-mediated gene transfer is a key stepping stone to allow a full understanding of their role in the environment and wider impact.}, } @article {pmid36097751, year = {2022}, author = {Seo, CW and Kim, YK and An, JL and Kim, JS and Kwon, PS and Yu, YB}, title = {The effect of photodynamic therapy using Radachlorin on biofilm-forming multidrug-resistant bacteria.}, journal = {Osong public health and research perspectives}, volume = {13}, number = {4}, pages = {290-297}, pmid = {36097751}, issn = {2210-9099}, support = {20A0088//Konyang University/ ; }, abstract = {OBJECTIVES: This study aimed to test the effect of photodynamic therapy (PDT) on the inhibition and removal of biofilms containing multidrug-resistant Acinetobacter baumannii.

METHODS: Using multidrug-resistant A. baumannii strains, an antibiotic susceptibility test was performed using the Gram-negative identification card of the Vitek 2 system (bioMérieux Inc., France), as well as an analysis of resistance genes, the effects of treatment with a light-emitting diode (LED) array using Radachlorin (RADA-PHARMA Co., Ltd., Russia), and transmission and scanning electron microscopy to confirm the biofilm-inhibitory effect of PDT.

RESULTS: The antibiotic susceptibility test revealed multiple resistance to the antibiotics imipenem and meropenem in the carbapenem class. A class-D-type β-lactamase was found, and OXA-23 and OXA-51 were found in 100% of 15 A. baumannii strains. After PDT using Radachlorin, morphological observations revealed an abnormal structure due to the loss of the cell membrane and extensive morphological changes, including low intracellular visibility and small vacuoles attached to the cell membrane.

CONCLUSION: PDT involving a combination of LED and Radachlorin significantly eliminated the biofilm of multidrug-resistant A. baumannii. Observations made using electron microscopy showed that PDT combining LED and Radachlorin was effective. Additional studies on the effective elimination of biofilms containing multidrug-resistant bacteria are necessary, and we hope that a treatment method superior to sterilization with antibiotics will be developed in the future.}, } @article {pmid36096436, year = {2022}, author = {Yasini, Z and Roghanizad, N and Fazlyab, M and Pourhajibagher, M}, title = {Ex vivo efficacy of sonodynamic antimicrobial chemotherapy for inhibition of Enterococcus faecalis and Candida albicans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103113}, doi = {10.1016/j.pdpdt.2022.103113}, pmid = {36096436}, issn = {1873-1597}, mesh = {Enterococcus faecalis ; Candida albicans ; Root Canal Irrigants/pharmacology ; *Photochemotherapy/methods ; Biofilms ; Sodium Hypochlorite/pharmacology/therapeutic use ; *Anti-Infective Agents/therapeutic use ; Dental Pulp Cavity ; }, abstract = {BACKGROUND: This study aimed to assess the ex vivo efficacy of sonodynamic antimicrobial chemotherapy (SACT) also known as antimicrobial sonodynamic therapy for inhibition of Enterococcus faecalis and Candida albicans biofilm.

MATERIALS AND METHODS: This study was conducted on 80 extracted single-canal maxillary anterior teeth. After instrumentation, the root canals were inoculated with E. faecalis and C. albicans suspensions, and the teeth were assigned to 5 groups of control (no antimicrobial therapy), nano-curcumin, ultrasound waves, 5.25% sodium hypochlorite (NaOCl), and SACT (nano-curcumin plus ultrasound waves). The mean biofilm thickness and number of colonies were then counted.

RESULTS: The E. faecalis colony count in nano-curcumin, ultrasound waves, and SACT groups was significantly lower than that in the control group (P<0.05). The C. albicans colony count in SACT group was significantly lower than that in the control and ultrasound waves groups (P<0.05). The mean biofilm thickness in NaOCl and SACT groups was significantly thinner than other groups (P<0.05). The mean biofilm thickness in SACT group was significantly thinner than that in ultrasound waves group (P<0.001).

CONCLUSION: In summary, SACT using nano-curcumin had an almost comparable efficacy to NaOCl, but was more effective than ultrasound waves and nano-curcumin for reduction of C. albicans and E. faecalis biofilm.}, } @article {pmid36096324, year = {2022}, author = {Shi, S and Fan, X and He, X and He, L and Cao, M and Wang, H and Zhou, J}, title = {Enhanced nitritation/denitritation and potential mechanism in an electrochemically assisted sequencing batch biofilm reactor treating sludge digester liquor with extremely low C/N ratios.}, journal = {Bioresource technology}, volume = {363}, number = {}, pages = {127936}, doi = {10.1016/j.biortech.2022.127936}, pmid = {36096324}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; Carbon ; Nitrites ; Nitrogen ; *Sewage/microbiology ; }, abstract = {Nitritation/denitritation is a promising strategy to treat sludge digester liquor but would be unstable and inefficient at extremely low C/N ratios. Here, a novel electrochemically assisted sequencing batch biofilm reactor (E-SBBR) was established to treat synthetic/real sludge digester liquor with decreasing C/N ratios. The results showed that the E-SBBR achieved stable nitritation and appreciable TN removal (>70 %) even at C/N < 0.5. The high-strength free ammonium (FA) (91.1-132.8 mg NH3-N/L) and long inhibition time (>9h) magnified by electrolysis promoted the robustness of nitritation through efficient nitrite-oxidizing bacteria elimination. Meanwhile, mass balance denoted that heterotrophic denitritation dominated in the enhanced TN removal and relied on carbon supplementation from cell apoptosis/lysis stimulated by electrolysis and high-strength FA, further supported by the recovery of heterotrophic denitrifiers, fermentation bacteria, and relevant functional genes at extremely low C/N ratios. This study provides a novel nitrogen removal approach for the sludge digester liquor treatment.}, } @article {pmid36096027, year = {2022}, author = {Zuo, P and Metz, J and Yu, P and Alvarez, PJJ}, title = {Biofilm-responsive encapsulated-phage coating for autonomous biofouling mitigation in water storage systems.}, journal = {Water research}, volume = {224}, number = {}, pages = {119070}, doi = {10.1016/j.watres.2022.119070}, pmid = {36096027}, issn = {1879-2448}, mesh = {Bacteria ; *Bacteriophages ; Biofilms ; *Biofouling/prevention & control ; *Chitosan ; *Disinfectants/pharmacology ; *Drinking Water/microbiology ; Glucose ; Plastics ; Polyphosphates ; }, abstract = {Biofilms in water storage systems may harbor pathogens that threaten public health. Chemical disinfectants are marginally effective in eradicating biofilms due to limited penetration, and often generate harmful disinfection byproducts. To enhance biofouling mitigation in household water storage tanks, we encapsulated bacteriophages (phages) in chitosan crosslinked with tri-polyphosphate and 3-glycidoxypropyltrimethoxysilane. Phages served as self-propagating green biocides that exclusively infect bacteria. This pH-responsive encapsulation (244 ± 11 nm) enabled autonomous release of phages in response to acidic pH associated with biofilms (corroborated by confocal microscopy with pH-indicator dye SNARF-4F), but otherwise remained stable in pH-neutral tap water for one month. Encapsulated phages instantly bind to plasma-treated plastic and fiberglass surfaces, providing a facile coating method that protects surfaces highly vulnerable to biofouling. Biofilm formation assays were conducted in tap water amended with 200 mg/L glucose to accelerate growth and attachment of Pseudomonas aeruginosa, an opportunistic pathogen commonly associated with biofilms in drinking water distribution and storage systems. Biofilms formation on plastic surfaces coated with encapsulated phages decreased to only 6.7 ± 0.2% (on a biomass basis) relative to the uncoated controls. Likewise, biofilm surface area coverage (4.8 ± 0.2 log CFU/mm[2]) and live/dead fluorescence ratio (1.80) were also lower than the controls (6.6 ± 0.2 log CFU/mm[2] and live/dead ratio of 11.05). Overall, this study offers proof-of-concept of a chemical-free, easily implementable approach to control problematic biofilm-dwelling bacteria and highlights benefits of this bottom-up biofouling control approach that obviates the challenge of poor biofilm penetration by biocides.}, } @article {pmid36095193, year = {2022}, author = {Zarnowski, R and Sanchez, H and Jaromin, A and Zarnowska, UJ and Nett, JE and Mitchell, AP and Andes, D}, title = {A common vesicle proteome drives fungal biofilm development.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {38}, pages = {e2211424119}, pmid = {36095193}, issn = {1091-6490}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; *Candida albicans/drug effects/genetics/physiology ; Drug Resistance, Fungal ; *Extracellular Vesicles/metabolism ; *Fungal Proteins/metabolism ; Proteome/metabolism ; }, abstract = {Extracellular vesicles mediate community interactions among cells ranging from unicellular microbes to complex vertebrates. Extracellular vesicles of the fungal pathogen Candida albicans are vital for biofilm communities to produce matrix, which confers environmental protection and modulates community dispersion. Infections are increasingly due to diverse Candida species, such as the emerging pathogen Candida auris, as well as mixed Candida communities. Here, we define the composition and function of biofilm-associated vesicles among five species across the Candida genus. We find similarities in vesicle size and release over the biofilm lifespan. Whereas overall cargo proteomes differ dramatically among species, a group of 36 common proteins is enriched for orthologs of C. albicans biofilm mediators. To understand the function of this set of proteins, we asked whether mutants in select components were important for key biofilm processes, including drug tolerance and dispersion. We found that the majority of these cargo components impact one or both biofilm processes across all five species. Exogenous delivery of wild-type vesicle cargo returned mutant phenotypes toward wild type. To assess the impact of vesicle cargo on interspecies interactions, we performed cross-species vesicle addition and observed functional complementation for both biofilm phenotypes. We explored the biologic relevance of this cross-species biofilm interaction in mixed species and mutant studies examining the drug-resistance phenotype. We found a majority of biofilm interactions among species restored the community's wild-type behavior. Our studies indicate that vesicles influence the development of protective monomicrobial and mixed microbial biofilm communities.}, } @article {pmid36095153, year = {2022}, author = {Jin, W and Song, P and Wu, Y and Tao, Y and Yang, K and Gui, L and Zhang, W and Ge, F}, title = {Biofilm Microenvironment-Mediated MoS2 Nanoplatform with Its Photothermal/Photodynamic Synergistic Antibacterial Molecular Mechanism and Wound Healing Study.}, journal = {ACS biomaterials science & engineering}, volume = {8}, number = {10}, pages = {4274-4288}, doi = {10.1021/acsbiomaterials.2c00856}, pmid = {36095153}, issn = {2373-9878}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; Drug Delivery Systems/methods ; Escherichia coli ; Humans ; Mice ; *Molybdenum/chemistry/pharmacology ; Phototherapy/methods ; Polyethyleneimine/pharmacology ; *Saponins ; Staphylococcus aureus ; Wound Healing ; }, abstract = {Drug-resistant bacterial infections pose a serious threat to human public health. Biofilm formation is one of the main factors contributing to the development of bacterial resistance, characterized by a hypoxic and microacidic microenvironment. Traditional antibiotic treatments have been ineffective against multidrug-resistant (MDR) bacteria. Novel monotherapies have had little success. On the basis of the photothermal effect, molybdenum disulfide (MoS2) nanoparticles were used to link quaternized polyethylenimine (QPEI), dihydroporphyrin e6 (Ce6), and Panax notoginseng saponins (PNS) in a zeolitic imidazolate framework-8 (ZIF-8). A multifunctional nanoplatform (MQCP@ZIF-8) was constructed with dual response to pH and near-infrared light (NIR), which resulted in synergistic photothermal and photodynamic antibacterial effects. The nanoplatform exhibited a photothermal conversion efficiency of 56%. It inhibited MDR Escherichia coli (E. coli) and MDR Staphylococcus aureus (S. aureus) by more than 95% and effectively promoted wound healing in mice infected with MDR S. aureus. The nanoplatform induced the death of MDR bacteria by promoting biofilm ablation, disrupting bacterial cell membranes and intracellular DNA, and interfering with intracellular material and energy metabolism. In this study, a multifunctional nanoplatform with good antibacterial effect was developed. The molecular mechanisms of MDR bacteria were also elucidated for possible clinical application.}, } @article {pmid36094177, year = {2022}, author = {Chen, YM and Wang, HY and Wu, CH and Lin, YJ and Chiu, CH}, title = {Prevalence of Type IV Pili-Mediated Twitching Motility in Streptococcus sanguinis Strains and Its Impact on Biofilm Formation and Host Adherence.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {18}, pages = {e0140322}, pmid = {36094177}, issn = {1098-5336}, mesh = {Adenosine Triphosphatases/metabolism ; Agar/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Fimbriae Proteins/genetics ; Fimbriae, Bacterial/genetics/metabolism ; Ligands ; Prevalence ; *Streptococcus sanguis/genetics/metabolism ; }, abstract = {Type IV pili (Tfp) are known to mediate several biological activities, including surface-dependent twitching motility. Although a pil gene cluster for Tfp biosynthesis is found in all sequenced Streptococcus sanguinis strains, Tfp-mediated twitching motility is less commonly detected. Upon examining 81 clinical strains, 39 strains generated twitching zones on blood agar plates (BAP), while 27 strains displayed twitching on Todd-Hewitt (TH) agar. Although BAP appears to be more suitable for the development of twitching zones, 5 strains exhibited twitching motility only on TH agar, indicating that twitching motility is not only strain specific but also sensitive to growth media. Furthermore, different twitching phenotypes were observed in strains expressing comparable levels of pilT, encoding the retraction ATPase, suggesting that the twitching phenotype on agar plates is regulated by multiple factors. By using a PilT-null and a pilin protein-null derivative (CHW02) of twitching-active S. sanguinis CGMH010, we found that Tfp retraction was essential for biofilm stability. Further, biofilm growth was amplified in CHW02 in the absence of shearing force, indicating that S. sanguinis may utilize other ligands for biofilm formation in the absence of Tfp. Similar to SK36, Tfp from CGMH010 were required for colonization of host cells, but PilT only marginally affected adherence and only in the twitching-active strain. Taken together, the results suggest that Tfp participates in host cell adherence and that Tfp retraction facilitates biofilm stability. IMPORTANCE Although the gene clusters encoding Tfp are commonly present in Streptococcus sanguinis, not all strains express surface-dependent twitching motility on agar surfaces. Regardless of whether the Tfp could drive motility, Tfp can serve as a ligand for the colonization of host cells. Though many S. sanguinis strains lack twitching activity, motility can enhance biofilm stability in a twitching-active strain; thus, perhaps motility provides little or no advantage to the survival of bacteria within dental plaque. Rather, Tfp retraction could provide additional advantages for the bacteria to establish infections outside the oral cavity.}, } @article {pmid36092682, year = {2022}, author = {Raj, DS and Dhamodharan, D and Thanigaivel, S and Vickram, AS and Byun, HS}, title = {Nanoemulsion as an Effective Inhibitor of Biofilm-forming Bacterial Associated Drug Resistance: An Insight into COVID Based Nosocomial Infections.}, journal = {Biotechnology and bioprocess engineering : BBE}, volume = {27}, number = {4}, pages = {543-555}, pmid = {36092682}, issn = {1226-8372}, abstract = {Antibiotic overuse has resulted in the microevolution of drug-tolerant bacteria. Understandably it has become one of the most significant obstacles of the current century for scientists and researchers to overcome. Bacteria have a tendency to form biofilm as a survival mechanism. Biofilm producing microorganism become far more resistant to antimicrobial agents and their tolerance to drugs also increases. Prevention of biofilm development and curbing the virulency factors of these multi drug resistant or tolerant bacterial pathogens is a newly recognised tactic for overcoming the challenges associated with such bacterial infections and has become a niche to be addressed. In order to inhibit virulence and biofilm from planktonic bacteria such as, Pseudomonas aeruginosa, Acinetobacter baumannii, and others, stable nanoemulsions (NEs) of essential oils (EOs) and their bioactive compounds prove to be an interesting solution. These NEs demonstrated significantly greater anti-biofilm and anti-virulence activity than commercial antibiotics. The EO reduces disease-causing gene expression, which is required for pathogenicity, biofilm formation and attachment to the surfaces. Essential NE and NE-loaded hydrogel surface coatings demonstrates superior antibiofilm activity which can be employed in healthcare-related equipments like glass, plastic, and metal chairs, hospital beds, ventilators, catheters, and tools used in intensive care units. Thus, anti-virulence and anti-biofilm forming strategies based on NEs-loaded hydrogel may be used as coatings to combat biofilm-mediated infection on solid surfaces.}, } @article {pmid36090086, year = {2022}, author = {Kapadia, C and Kachhdia, R and Singh, S and Gandhi, K and Poczai, P and Alfarraj, S and Ansari, MJ and Gafur, A and Sayyed, RZ}, title = {Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {977669}, pmid = {36090086}, issn = {1664-302X}, abstract = {The quorum-sensing (QS) cascade is responsible for the colonization and phenotypic behavior of the pathogenic organism and the regulation of diverse signal molecules. The disruption of the quorum-sensing system is an effective strategy to overcome the possibility of antibiotic resistance development in the pathogen. The quorum quenching does not kill the microbes. Instead, it hinders the expression of pathogenic traits. In the present experiment, Pseudomonas aeruginosa RKC1 was used to extract the metabolites responsible for quorum-sensing inhibition in soft rot pathogen Lelliottia amnigena RCE. During the initial screening, P. aeruginosa RKC1 was found to be most promising and inhibits violacein of Chromobacterium violaceum MTCC2656 pyocyanin, swarming-swimming motility of P. aeruginosa MTCC2297. The characterization of metabolites produced by the microbes which are responsible for quorum-sensing inhibition through GC-MS is very scarce in scientific literature. The ethyl acetate extract of P. aeruginosa RKC1 inhibits biofilm formation of L. amnigena RCE while inhibiting growth at higher concentrations. The GC-MS analysis suggested that Cyclic dipeptides (CDPs) such as Cyclo (L-prolyl-L-valine), Cyclo (Pro-Leu), and Cyclo(D-phenylalanyl-L-prolyl) were predominantly found in the ethyl acetate extract of the P. aeruginosa RKC1 (93.72%). This diketopiperazine (DKPs) exhibited quorum-sensing inhibition against the pathogen in liquid media during the active growth phase and regulated diverse metabolites of the pathogen. Moreover, the metabolites data from the clear zone around wells showed a higher concentration of DKSs (9.66%) compared to other metabolites. So far, very few reports indicate the role of DKPs or CDPs in inhibiting the quorum-sensing system in plant pathogenic bacteria. This is one such report that exploits metabolites of P. aeruginosa RKC1. The present investigation provided evidence to use quorum-sensing inhibitor metabolites, to suppress microbes' pathogenesis and thus develop an innovative strategy to overcome antibiotic resistance.}, } @article {pmid36089638, year = {2022}, author = {Wang, Y and Bian, Z and Wang, Y}, title = {Biofilm formation and inhibition mediated by bacterial quorum sensing.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {19-20}, pages = {6365-6381}, pmid = {36089638}, issn = {1432-0614}, support = {No. 42176108//National Natural Science Foundation of China/ ; No. 31870023//National Natural Science Foundation of China/ ; No. tsqn202103029//Young Taishan Scholars Program of Shandong Province/ ; No. 201941009//Fundamental Research Funds for the Central Universities/ ; }, mesh = {*Acyl-Butyrolactones/pharmacology ; Bacteria ; Biofilms ; Humans ; Indoles/pharmacology ; *Quorum Sensing ; }, abstract = {As a complex microbial aggregate, biofilm is a group behavior of bacterial ability to adapt to the environment. Bacteria produce biofilm substrates that enhance their tolerance to stress and cause microbial infections. Biofilm infection is usually closely related to virulence, pathogenicity, and even life-threatening to immunocompromised patients. Therefore, studying bacterial biofilm generation and regulatory mechanisms has become one of the most important fields. It is well known that biofilm formation involves group behavior and relies on complex regulation of quorum sensing (QS). A series of small molecule compounds such as indole, AI-2 (autoinducer-2), AHL (N-acyl-homoserine lactone), AIP (auto-inducing peptide), and DSF (diffusible signal factor) are widely available intraspecific or interspecific signaling molecules, with regulatory functions on a wide range of physiological activities of bacteria, including biofilm formation. Given that various bacteria employ QS mechanisms to regulate biofilm formation, inhibition of QS becomes a promising potential strategy for the treatment of bacterial infections. Here, we describe how bacterial intraspecific and interspecific signaling molecules regulate the mechanism of biofilm formation and dispersion. This may contribute to anti-biofilm active molecules and provide ideas or directions for studies on controlling bacterial infections by inhibiting biofilm formation through QS. KEY POINTS: • The formation and hazard of biofilm have been discussed. • The effects of quorum sensing on biofilm formation have been highlighted. • The inhibition of biofilm through quorum sensing has been discussed and highlighted.}, } @article {pmid36089570, year = {2022}, author = {Zhang, X and Wang, M and Bao, X and Li, P and Cui, A and Meng, X and Huang, Q and Li, S}, title = {Sub-inhibitory concentrations of cefotaxime treatment enhances biofilm formation of monophasic Salmonella Typhimurium variant strain SH16SP46.}, journal = {FEMS microbiology letters}, volume = {369}, number = {1}, pages = {}, doi = {10.1093/femsle/fnac092}, pmid = {36089570}, issn = {1574-6968}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cefotaxime/pharmacology ; Cellulose ; Gentian Violet/pharmacology ; Humans ; *Salmonella typhimurium ; }, abstract = {Salmonella is one of the most important foodborne and zoonotic pathogens, and monophasic S. Typhimurium is ranked among the top-five Salmonella serovars causing animal and human infections worldwide. Resistance to the third- and higher-generation cephalosporins in Salmonella has attracted great attention. Bacteria are frequently exposed to sub-minimal inhibitory concentrations (sub-MICs) of antimicrobials that can trigger diverse adaptive responses such as biofilm formation. Biofilms can promote bacterial defense to external and internal harsh conditions. This study aimed to investigate the effect of sub-MICs of cefotaxime, one of the third-generation cephalosporins, on biofilm formation by non-clinical S. enterica strains. Crystal violet staining demonstrated that cefotaxime at 1/8 MIC enhanced biofilm formation by two monophasic S. Typhimurium strains. Confocal laser scanning microscopy and enzymatic treatment assay revealed that cellulose was the most dominant extracellular matrix component contributing to Salmonella biofilm formation. Scanning electron microscopy demonstrated that cefotaxime treatment led to bacterial incomplete cell division and filamentous morphology during the whole process of biofilm formation. Our study is the first to report the enhancement effect of cefotaxime on non-clinical, monophasic S. Typhimurium by affecting bacterial morphology. The results will contribute to conducting risk assessments of Salmonella in the pork production chain and guiding the rational use of antimicrobial agents to reduce the risk of biofilm formation.}, } @article {pmid36089227, year = {2022}, author = {Rajasenan, S and Osmani, AH and Osmani, SA}, title = {Modulation of sensitivity to gaseous signaling by sterol-regulatory hypoxic transcription factors in Aspergillus nidulans biofilm cells.}, journal = {Fungal genetics and biology : FG & B}, volume = {163}, number = {}, pages = {103739}, doi = {10.1016/j.fgb.2022.103739}, pmid = {36089227}, issn = {1096-0937}, mesh = {*Aspergillus nidulans/genetics/metabolism ; Aspergillus fumigatus/genetics ; Transcription Factors/genetics/metabolism ; Sterols/metabolism ; Fungal Proteins/genetics/metabolism ; Gases/metabolism ; Sterol Regulatory Element Binding Proteins/genetics ; Hypoxia ; Biofilms ; Ergosterol/metabolism ; }, abstract = {Fungal biofilm founder cells experience self-generated hypoxia leading to dramatic changes in their cell biology. For example, during Aspergillus nidulans biofilm formation microtubule (MT) disassembly is triggered causing dispersal of EB1 from MT tips. This process is dependent on SrbA, a sterol regulatory element-binding transcription factor required for adaptation to hypoxia. We show that SrbA, an ER resident protein prior to activation, is proteolytically activated during early stages of biofilm formation and that, like SrbA itself, its activating proteases are also required for normal biofilm MT disassembly. In addition to SrbA, the AtrR transcription factor is also found to be required to modulate cellular responses to gaseous signaling during biofilm development. Using co-cultures, we further show that cells lacking srbA or atrR are capable of responding to biofilm generated gaseous microenvironments but are actually more sensitive to this signal than wild type cells. SrbA is a regulator of ergosterol biosynthetic genes and we find that the levels of seven GFP-tagged Erg proteins differentially accumulate during biofilm formation with various dependencies on SrbA for their accumulation. This uncovers a complex pattern of regulation with biofilm accumulation of only some Erg proteins being dependent on SrbA with others accumulating to higher levels in its absence. Because different membrane sterols are known to influence cell permeability to gaseous molecules, including oxygen, we propose that differential regulation of ergosterol biosynthetic proteins by SrbA potentially calibrates the cell's responsiveness to gaseous signaling which in turn modifies the cell biology of developing biofilm cells.}, } @article {pmid36089036, year = {2022}, author = {Liang, C and Carvalho, PN and Bester, K}, title = {Effects of substrate loading on co-metabolic transformation pathways and removal rates of pharmaceuticals in biofilm reactors.}, journal = {The Science of the total environment}, volume = {853}, number = {}, pages = {158607}, doi = {10.1016/j.scitotenv.2022.158607}, pmid = {36089036}, issn = {1879-1026}, mesh = {*Wastewater/chemistry ; Waste Disposal, Fluid/methods ; Bioreactors ; Diclofenac ; Venlafaxine Hydrochloride ; *Tramadol ; Biofilms ; Pharmaceutical Preparations ; }, abstract = {This study focused on the effects of substrate (raw wastewater) on the biological removal of 20 pharmaceuticals in moving bed biofilm reactors. This is the first study discriminating experimentally between effects of adaptation (45 d) and stimulation (100 h) on the removal of micropollutants. The results presented in this paper show: i) Tramadol and venlafaxine are subject to microbial N-oxidation (besides the known demethylation). ii) Changes in substrate loading, changed the preferential degradation pathways, e.g., from N-oxidation (under starvation) to N-demethylation of both model compounds: tramadol and venlafaxine, during adaptation and stimulation to high substrate supply. iii) In starving biofilms, the effects of stimulation on removal rates are minor (-100 to +150 %) in comparison to those caused by adaptation (-100 to +700 %). iv) Adaptation to high loadings resulted in increased removal rates (up to 700 % in selected cases) v) Adaptation to high loadings followed by high loading of stimulation, resulted in the highest increase of removal rates (+49 % to +1800 %) for hard-to-degrade compounds (e.g., diclofenac). All in all, this study shows that the efficiency of biofilm reactors is heavily dependent on their adaptation to substrate.}, } @article {pmid36088584, year = {2023}, author = {Hofer, RN and Lin, A and House, BC and Purvis, CN and Harris, BJ and Symes, SJK and Giles, DK}, title = {Exogenous polyunsaturated fatty acids (PUFAs) influence permeability, antimicrobial peptide resistance, biofilm formation and membrane phospholipid structure in an A-layer and non-A-layer strain of Aeromonas salmonicida.}, journal = {Journal of fish diseases}, volume = {46}, number = {1}, pages = {31-45}, doi = {10.1111/jfd.13715}, pmid = {36088584}, issn = {1365-2761}, mesh = {Animals ; *Aeromonas salmonicida ; Antimicrobial Peptides ; Phospholipids ; *Fish Diseases ; Fatty Acids, Unsaturated ; }, abstract = {Aeromonas salmonicida is a Gram-negative bacterium that can infect a wide host range of fish populations, including salmonids and non-salmonids as well as freshwater and marine life. Some strains of A. salmonicida cause the disease furunculosis, which can cause lethargy, intestinal inflammation, ulcers, haemorrhaging and death. The infection is spread through fish-to-fish contact, and the presence of infection can have devastating effects on cultivated fish populations. The purpose of this study was to explore the ability of non-A-layer and A-layer A. salmonicida strains to incorporate polyunsaturated fatty acids (PUFAs) into their lipid profile and test the phenotypic effects thereof. Lipids were extracted from PUFA-exposed cultures and analysed for lipid modification by thin-layer chromatography and ultraperformance liquid chromatography-mass spectrometry, showing A. salmonicida, regardless of A-layer, capable of incorporating all seven of the PUFAs studied. Phenotypic effects were determined through the use of assays that tested for biofilm formation, membrane permeability and cyclic peptide susceptibility. Temperature-dependent effects on biofilm formation were observed, and PUFA exposure showed significant (p < .001) increases in membrane permeability as tested by the uptake of the hydrophobic compounds crystal violet and ethidium bromide. Additionally, some PUFAs elicited modest protection and vulnerability against the membrane-targeting cyclic peptides polymyxin B (PMB) and colistin. The diverse, strain-specific responses to exogenous PUFAs may allude to evolved adaptive strategies that enhance survival, persistence and virulence of non-pathogenic and pathogenic members of bacteria that oscillate between environmental and fish host niches.}, } @article {pmid36083296, year = {2022}, author = {Liu, X and Fan, D and Feng, X and Zheng, Y and Wegner, SV and Liu, M and Chen, F and Zeng, W}, title = {Breaching Bacterial Biofilm Barriers: Efficient Combinatorial Theranostics for Multidrug-Resistant Bacterial Biofilms with a Novel Penetration-Enhanced AIEgen Probe.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {37}, pages = {41671-41683}, doi = {10.1021/acsami.2c07378}, pmid = {36083296}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Mammals ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; Microbial Sensitivity Tests ; Precision Medicine ; Vancomycin/pharmacology ; Virulence Factors/pharmacology ; Water ; }, abstract = {The formation of microbial biofilms is acknowledged as a major virulence factor in a range of persistent local infections. Failures to remove biofilms with antibiotics foster the emergence of antibiotic-resistant bacteria and result in chronic infections. As a result, the construction of effective biofilm-inhibiting and biofilm-eradicating chemicals is urgently required. Herein, we designed a water-soluble probe APDIS for membrane-active fluorescence and broad-spectrum antimicrobial actions, particularly against methicillin-resistant Staphylococcus aureus (MRSA), which shows multidrug resistance. In vitro and in vivo experiments demonstrate its high antibacterial effects comparable to vancomycin. Furthermore, it inhibits biofilm formation by effectively killing planktonic bacteria at low inhibitory concentrations, without toxicity to mammalian cells. More importantly, this probe can efficiently penetrate through biofilm barriers and exterminate bacteria that are enclosed within biofilms and startle existing biofilms. In the mouse model of implant-related biofilm infections, this probe exhibits strong antibiofilm activity against MRSA biofilms, thus providing a novel theranostic strategy to disrupt biofilms in vivo effectively. Our results indicate that this probe has the potential to be used for the development of a combinatorial theranostic platform with synergistic enhanced effects for the treatment of multidrug-resistant bacterial infections and antibiofilm medications.}, } @article {pmid36082242, year = {2022}, author = {Liu, L and Liu, B and Li, L and He, MX and Zhou, XD and Li, Q}, title = {Myrtenol Inhibits Biofilm Formation and Virulence in the Drug-Resistant Acinetobacter baumannii: Insights into the Molecular Mechanisms.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {5137-5148}, pmid = {36082242}, issn = {1178-6973}, abstract = {BACKGROUND: blaNDM-1-producing Acinetobacter baumannii (BP-AB) remains a critical problem in nosocomial infections, because of its resistance mediated by the biofilm formation and virulence factors. No studies have confirmed myrtenol's efficacy in inhibiting the biofilm formation and virulence associated with biofilm of BP-AB.

METHODS: The tested concentrations of myrtenol were wild type (A), 50 μg/mL (B), 100 μg/mL (C), 200 μg/mL (D), 250 μg/mL (E), and 300 μg/mL (F).

RESULTS: The BP-AB biofilm inhibition was significantly higher in the D, E, and F groups than in the A, B, and C groups. Myrtenol significantly reduced the air-liquid interface ring formation in glass tubes. It also effectively inhibited the attachment of BP-AB strains on polystyrene surfaces as shown by crystal violet staining. Microscopy showed a significant reduction in biofilm formation with dispersed BP-AB strains. The confocal laser scanning microscopy analysis showed a significant reduction in the biofilm's biomass, covered surface area, and thickness. The scanning electron microscopy analysis revealed significantly fewer BP-AB aggregates on the coverslip surface. In the CompStat analysis, the biofilm's biomass, maximum thickness, and surface-to-volume ratio were significantly reduced. The qPCR analysis revealed a significant down-regulation of bfmR, bap, csuA/B, and ompA expression, which positively correlated with the biofilm's biomass, maximum thickness, and surface-to-volume ratio in BP-AB strains. Myrtenol significantly improved the susceptibility of BP-AB to the antibiotics amikacin, piperacillin/tazobactam, cefoperazone/sulbactam, and ceftazidime.

CONCLUSION: Myrtenol attenuates the BP-AB biofilm formation and virulence by suppressing the expression of bfmR, bap, csuA/B, and ompA.}, } @article {pmid36081767, year = {2022}, author = {Hall-Stoodley, L and McCoy, KS}, title = {Biofilm aggregates and the host airway-microbial interface.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {969326}, pmid = {36081767}, issn = {2235-2988}, support = {UL1 TR002733/TR/NCATS NIH HHS/United States ; }, mesh = {Bacteria ; Biofilms ; *Cystic Fibrosis/microbiology ; Haemophilus influenzae/physiology ; Humans ; *Pseudomonas Infections ; Pseudomonas aeruginosa/physiology ; Respiratory System/pathology ; }, abstract = {Biofilms are multicellular microbial aggregates that can be associated with host mucosal epithelia in the airway, gut, and genitourinary tract. The host environment plays a critical role in the establishment of these microbial communities in both health and disease. These host mucosal microenvironments however are distinct histologically, functionally, and regarding nutrient availability. This review discusses the specific mucosal epithelial microenvironments lining the airway, focusing on: i) biofilms in the human respiratory tract and the unique airway microenvironments that make it exquisitely suited to defend against infection, and ii) how airway pathophysiology and dysfunctional barrier/clearance mechanisms due to genetic mutations, damage, and inflammation contribute to biofilm infections. The host cellular responses to infection that contribute to resolution or exacerbation, and insights about evaluating and therapeutically targeting airway-associated biofilm infections are briefly discussed. Since so many studies have focused on Pseudomonas aeruginosa in the context of cystic fibrosis (CF) or on Haemophilus influenzae in the context of upper and lower respiratory diseases, these bacteria are used as examples. However, there are notable differences in diseased airway microenvironments and the unique pathophysiology specific to the bacterial pathogens themselves.}, } @article {pmid36081254, year = {2022}, author = {Zeng, W and Ma, S and Huang, Y and Xia, A and Zhu, X and Zhu, X and Liao, Q}, title = {Bifunctional lighting/supporting substrate for microalgal photosynthetic biofilm to bio-remove ammonia nitrogen from high turbidity wastewater.}, journal = {Water research}, volume = {223}, number = {}, pages = {119041}, doi = {10.1016/j.watres.2022.119041}, pmid = {36081254}, issn = {1879-2448}, mesh = {Ammonia ; Biofilms ; Biomass ; Lighting ; *Microalgae ; Nitrogen ; Wastewater ; }, abstract = {Treatment technologies based on microalgal biofilms have an enormous potential for dealing with water pollution because they can efficiently redirect nutrients from wastewater to renewable biomass feedstock. However, poor light transmittance is caused by the high turbidity of wastewater, which hinders the commercial application of microalgal biofilm-based wastewater treatment. Here, a bifunctional substrate with lighting and biofilm support functions was constructed using a light guide plate. In a biofilm photobioreactor (bPBR) with a bifunctional lighting/supporting substrate (BL/S substrate), light can directly irradiate the biofilm to avoid attenuation by the turbid wastewater. Direct irradiation of light onto the biofilm led to a 93.0% enhancement of microalgal photoconversion efficiency when compared to that of a supporting substrate without lighting (SO substrate). Meanwhile, the maximum growth rate of the microalgal biofilm on the BL/S substrate was 8.7 g m[-2] d[-1], which was increased by 60.3%. The removal rate of ammonia nitrogen (NH4[+]-N) from the digested wastewater contributed by the microalgal biofilm reached 22.6 mg L[-1] d[-1], which was higher than the previously reported that of NH4[+]-N from turbid digested wastewater by the biofilms. Furthermore, the BL/S substrate can facilitate the secretion of abundant extracellular polymeric substrates, which results in the stable adhesion of the biofilm onto the BL/S substrate. The optical density of the microalgae cells at the outlet of the bPBR with BL/S substrate was below 0.1, which was 94% lower than that of the bPBR with the SO substrate. The results indicated the BL/S substrate may avoid the loss of microalgal biomass, and almost all biomass could be easily harvested from the biofilm for algae-based biomass resources. Consequently, this study can offer a promising alternative with efficient treatment technologies for wastewater with high turbidity.}, } @article {pmid36080730, year = {2022}, author = {Eltayb, EK and Alqahtani, FY and Alkahtani, HM and Alsarra, IA and Alfaraj, R and Aleanizy, FS}, title = {Attenuation of Pseudomonas aeruginosa Quorum Sensing Virulence of Biofilm and Pyocyanin by mBTL-Loaded Calcium Alginate Nanoparticles.}, journal = {Polymers}, volume = {14}, number = {17}, pages = {}, pmid = {36080730}, issn = {2073-4360}, support = {RSP-2021/340//King Saud University/ ; }, abstract = {Pseudomonas aeruginosa contributes to many chronic infections and has been found to be resistant to multiple antibiotics. Pseudomonas use a quorum sensing system (QS) to control biofilm establishment and virulence factors, and, thus, quorum sensing inhibitors (QSIs), such as meta-bromo-thiolactone (mBTL), are promising anti-infective agents. Accordingly, this study intended to investigate the antibacterial and anti-virulence activity of mBTL-loaded calcium alginate nanoparticles (CANPs) against Pseudomonas aeruginosa and different QS mutants. The results show that the mBTL-CANPs had higher antibacterial activity, which was made evident by decreases in all tested strains except the ∆lasR/∆rhlR double mutant, with MIC50 (0.5 mg/mL) of mBTL-CANPs compared with free mBTL at MIC50 (˃1 mg/mL). The biofilm formation of P. aeruginosa and some QS-deficient mutants were reduced in response to 0.5-0.125 mg/mL of mBTL-encapsulating CANPs. The pyocyanin production of the tested strains except ∆lasA and ∆rhlR decreased when challenged with 0.5 mg/mL of mBTL-loaded NPs. The subsequent characterization of the cytotoxic effect of these NPs on human lung epithelial cells (A549) and cystic fibrosis fibroblast cells (LL 29) demonstrated that synthesized NPs were cytocompatible at MIC50 in both cell lines and markedly reduced the cytotoxic effect observed with mBTL alone on these cells. The resulting formulation reduced the P. aeruginosa strains' adhesion to A549 comparably with mBTL, suggesting their potential anti-adhesive effect. Given the virulence suppressing action, cytocompatibility, and enhanced anti-biofilm effect of mBTL-CANPs, and the advantage of alginate-based NPs as an antimicrobial delivery system these nanoparticles have great potential in the prophylaxis and treatment of infection caused by Pseudomonas aeruginosa.}, } @article {pmid36080283, year = {2022}, author = {Balázs, VL and Filep, R and Répás, F and Kerekes, E and Szabó, P and Kocsis, B and Böszörményi, A and Krisch, J and Horváth, G}, title = {Immortelle (Helichrysum italicum (Roth) G. Don) Essential Oil Showed Antibacterial and Biofilm Inhibitory Activity against Respiratory Tract Pathogens.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {17}, pages = {}, pmid = {36080283}, issn = {1420-3049}, support = {ÚNKP-21-4-I//New National Excellence Program of the Ministry for Innovation and Technology/ ; 18 K 128217//National Research, Development and Innovation Office, Hungary/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria ; Biofilms ; *Helichrysum/chemistry ; Humans ; Microbial Sensitivity Tests ; *Oils, Volatile/chemistry/pharmacology ; Pseudomonas aeruginosa ; }, abstract = {The biofilm formation of bacteria in different parts of the human body can influence the success of antibiotic therapy. Essential oils (EOs) and their components are becoming increasingly popular in point of view of medicinal applications, because of their antibacterial efficacy. The immortelle EO has been used traditionally as an expectorant; however, there are no studies summarizing its antibacterial effect against respiratory tract bacteria. Our aim was to investigate the antibacterial and biofilm inhibitory activity of immortelle (Helichrysum italicum) EO against respiratory tract pathogens such as Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa and Streptococcus pneumoniae. In order to prove the antibacterial effect of the immortelle EO, broth microdilution and biofilm inhibition tests, and membrane damage assay were investigated. Scanning electron microscopy was used to identify the structural modifications in bacterial cells. Our results showed that immortelle EO has antibacterial and anti-biofilm effects against respiratory tract bacteria used in this study. H. parainfluenzae was the most sensitive to each treatment, however, P. aeruginosa was the most resistant bacteria. In conclusion, the studied EO may have a role in the treatment of respiratory tract infections due to their antibacterial and anti-biofilm activity.}, } @article {pmid36079347, year = {2022}, author = {Dybowska-Józefiak, M and Wesołowska, M}, title = {The Influence of Biofilm on Selected Properties of Thin-Coat Mineral-Based Plasters on EPS Substrate.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {17}, pages = {}, pmid = {36079347}, issn = {1996-1944}, abstract = {This paper discusses changes in the microstructure and water absorption of thin-coat mineral-based plasters after prolonged exposure to the external environment and infected with biological corrosion. The results of laboratory and field tests for external thermal insulation composite system Styrofoam-based plasters are presented. The test samples were taken after 6 years of exposure to the external environment. The microstructure parameters such as porosity distribution and water absorption of the plasters were evaluated. The pore size ranges that were sensitive to frost corrosion and capillary flow were separated in the porosity distribution. Based on the porosity and absorption changes, it was found that biological corrosion interferes with the microstructure of the thin-coat mineral-based plasters on the expanded polystyrene substrate.}, } @article {pmid36077503, year = {2022}, author = {Song, J and Hong, L and Zou, X and Alshawwa, H and Zhao, Y and Zhao, H and Liu, X and Si, C and Zhang, Z}, title = {A Self-Supplying H2O2 Modified Nanozyme-Loaded Hydrogel for Root Canal Biofilm Eradication.}, journal = {International journal of molecular sciences}, volume = {23}, number = {17}, pages = {}, pmid = {36077503}, issn = {1422-0067}, support = {20200404184//Jilin Province Science and Technology Department/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Dental Pulp Cavity ; *Disinfectants/pharmacology ; *Enterococcus faecalis ; Hydrogels/pharmacology ; Hydrogen Peroxide/pharmacology ; Rats ; Rats, Sprague-Dawley ; Root Canal Therapy/methods ; }, abstract = {The success of root canal therapy depends mainly on the complete elimination of the root canal bacterial biofilm. The validity and biocompatibility of root canal disinfectant materials are imperative for the success of root canal treatment. However, the insufficiency of the currently available root canal disinfectant materials highlights that more advanced materials are still needed. In this study, a nanozyme-loaded hydrogel (Fe3O4-CaO2-Hydrogel) was modified and analyzed as a root canal disinfectant material. Fe3O4-CaO2-Hydrogel was fabricated and examined for its release profile, biocompatibility, and antibacterial activity against E. faecalis and S. sanguis biofilms in vitro. Furthermore, its efficiency in eliminating the root canal bacterial biofilm removal in SD rat teeth was also evaluated. The results in vitro showed that Fe3O4-CaO2-Hydrogel could release reactive oxygen species (ROS). Moreover, it showed good biocompatibility, disrupting bacterial cell membranes, and inhibiting exopolysaccharide production (p < 0.0001). In addition, in vivo results showed that Fe3O4-CaO2-Hydrogel strongly scavenged on root canal biofilm infection and prevented further inflammation expansion (p < 0.05). Altogether, suggesting that Fe3O4-CaO2-Hydrogel can be used as a new effective biocompatible root canal disinfectant material. Our research provides a broad prospect for clinical root canal disinfection, even extended to other refractory infections in deep sites.}, } @article {pmid36077428, year = {2022}, author = {Sousa, V and Mardas, N and Spratt, D and Hassan, IA and Walters, NJ and Beltrán, V and Donos, N}, title = {The Effect of Microcosm Biofilm Decontamination on Surface Topography, Chemistry, and Biocompatibility Dynamics of Implant Titanium Surfaces.}, journal = {International journal of molecular sciences}, volume = {23}, number = {17}, pages = {}, pmid = {36077428}, issn = {1422-0067}, mesh = {Biofilms ; Decontamination/methods ; *Dental Implants ; Humans ; Microscopy, Electron, Scanning ; *Peri-Implantitis ; Surface Properties ; Titanium/chemistry/pharmacology ; }, abstract = {Since the inception of dental implants, a steadily increasing prevalence of peri-implantitis has been documented. Irrespective of the treatment protocol applied for the management of peri-implantitis, this biofilm-associated pathology, continues to be a clinical challenge yielding unpredictable and variable levels of resolution, and in some cases resulting in implant loss. This paper investigated the effect of microcosm biofilm in vitro decontamination on surface topography, wettability, chemistry, and biocompatibility, following decontamination protocols applied to previously infected implant titanium (Ti) surfaces, both micro-rough -Sandblasted, Large-grit, Acid-etched (SLA)-and smooth surfaces -Machined (M). Microcosm biofilms were grown on SLA and M Ti discs. These were treated with TiBrushes (TiB), combination of TiB and photodynamic therapy (PDT), combination of TiB and 0.2%CHX/1%NaClO, plus or minus Ultraviolet-C (UV-C) radiation. Surface topography was evaluated by Scanning Electron Microscopy (SEM) and Laser Surface Profilometry. Surface function was analysed through wettability analysis. Surface chemistry evaluation of the discs was performed under SEM/Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). Biocompatibility was tested with the cytocompatibility assay using human osteoblast-like osteosarcoma cell line (MG-63) cells. Elemental analysis of the discs disclosed chemical surface alterations resulting from the different treatment modalities. Titanium, carbon, oxygen, sodium, aluminium, silver, were identified by EDX as the main components of all the discs. Based on the data drawn from this study, we have shown that following the decontamination of Ti surfaces the biomaterial surface chemistry and topography was altered. The type of treatment and Ti surface had a significant effect on cytocompatibility (p = 0.0001). Although, no treatment modality hindered the titanium surface biocompatibility, parameters such as the use of chemical agents and micro-rough surfaces had a higher cytotoxic effect in MG-63 cells. The use of smooth surfaces, and photofunctionalisation of the TiO2 layer had a beneficial effect on cytocompatibility following decontamination.}, } @article {pmid36077302, year = {2022}, author = {Guo, J and Deng, X and Zhang, Y and Song, S and Zhao, T and Zhu, D and Cao, S and Baryshnikov, PI and Cao, G and Blair, HT and Chen, C and Gu, X and Liu, L and Zhang, H}, title = {The Flagellar Transcriptional Regulator FtcR Controls Brucella melitensis 16M Biofilm Formation via a betI-Mediated Pathway in Response to Hyperosmotic Stress.}, journal = {International journal of molecular sciences}, volume = {23}, number = {17}, pages = {}, pmid = {36077302}, issn = {1422-0067}, support = {31860691//NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA,/ ; 2021AB012//SCIENTIFIC AND TECHNOLOGICAL PROJECTS OF CORPS/ ; GJHZ201709//INTERNATIONAL SCIENCE AND TECHNOLOGY COOPERATION PROMOTION PLAN/ ; CZ027202//TRAINING PROGRAM FOR EXCELLENT YOUNG TEACHERS COLLEGES AND UNIVERSITIES OF CORPS/ ; 2017CB002//YOUTH SCIENCE AND TECHNOLOGY INNOVATION LEADING TALENT PROGRAM OF CORPS/ ; 2021MD703890//CHINA POSTDOCTORAL SCIENCE FOUNDATION REGIONAL SPECIAL SUPPORT PROGRAM/ ; XJ2021G105//AUTONOMOUS REGION GRADUATE EDUCATION INNOVATION PROGRAM/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Brucella melitensis/metabolism ; *Brucellosis ; Gene Expression Regulation, Bacterial ; Humans ; Transcription Factors/genetics/metabolism ; Virulence/genetics ; }, abstract = {The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system's expression, and is critical for B. melitensis 16M's flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria's survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress.}, } @article {pmid36077040, year = {2022}, author = {Fei, N and Ji, W and Yang, L and Yu, C and Qiao, P and Yan, J and Guan, W and Yang, Y and Zhao, T}, title = {Hcp of the Type VI Secretion System (T6SS) in Acidovorax citrulli Group II Strain Aac5 Has a Dual Role as a Core Structural Protein and an Effector Protein in Colonization, Growth Ability, Competition, Biofilm Formation, and Ferric Iron Absorption.}, journal = {International journal of molecular sciences}, volume = {23}, number = {17}, pages = {}, pmid = {36077040}, issn = {1422-0067}, support = {CARS-25//Ministry of agriculture of China/ ; 2018YFD0201300//Ministry of science and technology of China/ ; S2022XM25//Ministry of finance of the people's Republic of China/ ; CAAS-ASTIP//Chinese Academy of Agricultural Sciences/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Biological Phenomena ; Comamonadaceae ; Iron ; *Type VI Secretion Systems/genetics/metabolism ; }, abstract = {A type VI secretion system (T6SS) gene cluster has been reported in Acidovorax citrulli. Research on the activation conditions, functions, and the interactions between key elements in A. citrulli T6SS is lacking. Hcp (Hemolysin co-regulated protein) is both a structural protein and a secretion protein of T6SS, which makes it a special element. The aims of this study were to determine the role of Hcp and its activated conditions to reveal the functions of T6SS. In virulence and colonization assays of hcp deletion mutant strain Δhcp, tssm (type VI secretion system membrane subunit) deletion mutant strain Δtssm and double mutant ΔhcpΔtssm, population growth was affected but not virulence after injection of cotyledons and seed-to-seedling transmission on watermelon. The population growth of Δhcp and Δtssm were lower than A. citrulli wild type strain Aac5 of A. citrulli group II at early stage but higher at a later stage. Deletion of hcp also affected growth ability in different culture media, and the decline stage of Δhcp was delayed in KB medium. Biofilm formation ability of Δhcp, Δtssm and ΔhcpΔtssm was lower than Aac5 with competition by prey bacteria but higher in KB and M9-Fe[3+] medium. Deletion of hcp reduced the competition and survival ability of Aac5. Based on the results of Western blotting and qRT-PCR analyses, Hcp is activated by cell density, competition, ferric irons, and the host plant. The expression levels of genes related to bacterial secretion systems, protein export, and several other pathways, were significantly changed in the Δhcp mutant compared to Aac5 when T6SS was activated at high cell density. Based on transcriptome data, we found that a few candidate effectors need further identification. The phenotypes, activated conditions and transcriptome data all supported the conclusion that although there is only one T6SS gene cluster present in the A. citrulli group II strain Aac5, it related to multiple biological processes, including colonization, growth ability, competition and biofilm formation.}, } @article {pmid36076837, year = {2022}, author = {Fokt, H and Cleto, S and Oliveira, H and Araújo, D and Castro, J and Cerca, N and Vieira, MJ and Almeida, C}, title = {Bacteriocin Production by Escherichia coli during Biofilm Development.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {17}, pages = {}, pmid = {36076837}, issn = {2304-8158}, support = {PTDC/CVT-CVT/4620/2021//Fundação para a Ciência e Tecnologia/ ; UIDB/04469/2020//Fundação para a Ciência e Tecnologia/ ; UIDB/00511/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {Escherichia coli is a highly versatile bacterium ranging from commensal to intestinal pathogen, and is an important foodborne pathogen. E. coli species are able to prosper in multispecies biofilms and secrete bacteriocins that are only toxic to species/strains closely related to the producer strain. In this study, 20 distinct E. coli strains were characterized for several properties that confer competitive advantages against closer microorganisms by assessing the biofilm-forming capacity, the production of antimicrobial molecules, and the production of siderophores. Furthermore, primer sets for E. coli bacteriocins-colicins were designed and genes were amplified, allowing us to observe that colicins were widely distributed among the pathogenic E. coli strains. Their production in the planktonic phase or single-species biofilms was uncommon. Only two E. coli strains out of nine biofilm-forming were able to inhibit the growth of other E. coli strains. There is evidence of larger amounts of colicin being produced in the late stages of E. coli biofilm growth. The decrease in bacterial biomass after 12 h of incubation indicates active type I colicin production, whose release normally requires E. coli cell lysis. Almost all E. coli strains were siderophore-producing, which may be related to the resistance to colicin as these two molecules may use the same transporter system. Moreover, E. coli CECT 504 was able to coexist with Salmonella enterica in dual-species biofilms, but Shigella dysenteriae was selectively excluded, correlating with high expression levels of colicin (E, B, and M) genes observed by real-time PCR.}, } @article {pmid36076447, year = {2022}, author = {Wang, L and Liu, L and Liu, Y and Wang, F and Zhou, X}, title = {Antimicrobial performance of novel glutathione-conjugated silver nanoclusters (GSH@AgNCs) against Escherichia coli and Staphylococcus aureus by membrane-damage and biofilm-inhibition mechanisms.}, journal = {Food research international (Ottawa, Ont.)}, volume = {160}, number = {}, pages = {111680}, doi = {10.1016/j.foodres.2022.111680}, pmid = {36076447}, issn = {1873-7145}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; *Escherichia coli Infections ; Glutathione ; Humans ; Nanostructures ; *Silver/pharmacology ; Staphylococcus aureus ; }, abstract = {Bacterial infection has become an important factor affecting human health, and the increasing antibiotic resistance has seriously hindered the treatment of infectious diseases. This study aimed to explore a novel nanotechnology that combines silver with glutathione (GSH) to form antibacterial nanoclusters, GSH@AgNCs. The composite was characterized using a UV fluorescence spectrophotometer, high-resolution transmission electron microscopy (HR-TEM), particle size-zeta potential, fourier transform infrared (FTIR), X-ray photoelectron spectrometer (XPS), thermal gravimetric analysis (TGA), and X-ray diffraction analysis (XRD). This study examined the inhibitory effect of GSH@AgNCs on the bacterial growth and biofilm formation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as its antibacterial mechanisms. The results indicated that GSH@AgNCs were more successful in restricting E. coli than S. aureus. The bacterial membrane exposed to GSH@AgNCs was damaged irreversibly, presenting cytoplasm leakage, membrane depolarization, ATPase activity decline, and cell degeneration. In addition, at low concentration (1/8 MIC), GSH@AgNCs significantly inhibited the formation of biofilms and damaged mature biofilms, reducing the viable cells. This study demonstrated that GSH@AgNCs effectively hindered the proliferation of foodborne Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli), providing new feasibility for applying organic composite nanomaterials and nanotechnology in the food industry.}, } @article {pmid36076252, year = {2022}, author = {Ghapanvari, P and Taheri, M and Jalilian, FA and Dehbashi, S and Dezfuli, AAZ and Arabestani, MR}, title = {The effect of nisin on the biofilm production, antimicrobial susceptibility and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {European journal of medical research}, volume = {27}, number = {1}, pages = {173}, pmid = {36076252}, issn = {2047-783X}, support = {9811018469//The vice chancellor for research and technology, Hamadan university of medical science/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacteriocins/pharmacology/therapeutic use ; Biofilms ; Humans ; Microbial Sensitivity Tests ; *Nisin/pharmacology/therapeutic use ; Pseudomonas aeruginosa ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; Virulence Factors/pharmacology/therapeutic use ; }, abstract = {OBJECTIVES: Staphylococcus aureus and Pseudomonas aeruginosa were the most common bacteria in nosocomial infections. Different bacteriocins are currently being studied as antibiotics or in conjunction with antibiotics as potential strategies to treat resistant infectious agents. The study aimed to determine nisin's effect on the biofilm production, antimicrobial susceptibility, and biofilm formation of S. aureus and P. aeruginosa.

MATERIALS AND METHODS: The experimental research tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The experimental study tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The MIC of bacteriocin nisin was determined using the micro broth dilution method, and crystal violet was used to assess the effect of bacteriocin on the biofilm. In addition, L929 cell culture was used to determine the effectiveness of bacteriocin on the isolate under similar cell conditions. Moreover, the MTT assay was used to and evaluate bacteriocin toxicity. In this study, the software Prism version 9 and Graph pad software were utilized.

RESULTS: The results of this study reveal that the nisin has different activities at different doses and is considered dose-dependent. At various times and doses, nisin inhibits biofilm formation in S. aureus, and P. aeruginosa isolates. Nisin also showed a decreasing survival of the isolates. Antibiotic-resistant bacteria can be made more vulnerable by nisin. Furthermore, nisin treatment affected the production of virulence factors such as hemolysins in S. aureus and had little or a negative effect on P. aeruginosa virulence factors. This medication stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage.

CONCLUSIONS: Antibacterial properties of nicin against S. aureus and P. aeruginosa were successfully studied. This bacteriocin stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage or death. Damage to the membrane among the fundamental causes is reduced membrane potential and enzyme inactivation.}, } @article {pmid36075785, year = {2023}, author = {Martín-Rodríguez, AJ}, title = {Respiration-induced biofilm formation as a driver for bacterial niche colonization.}, journal = {Trends in microbiology}, volume = {31}, number = {2}, pages = {120-134}, doi = {10.1016/j.tim.2022.08.007}, pmid = {36075785}, issn = {1878-4380}, mesh = {*Biofilms ; Oxidation-Reduction ; *Bacteria/metabolism ; Oxygen/metabolism ; Respiration ; }, abstract = {Depending on their physiology and metabolism, bacteria can carry out diverse redox processes for energy acquisition, which facilitates adaptation to environmental or host-associated niches. Of these processes, respiration, using oxygen or alternative terminal electron acceptors, is energetically the most favorable in heterotrophic bacteria. The biofilm lifestyle, a coordinated multicellular behavior, is ubiquitous in bacteria and is regulated by a variety of intrinsic and extrinsic cues. Respiration of distinct electron acceptors has been shown to induce biofilm formation or dispersal. The notion of biofilm formation regulation by electron acceptor availability and respiration has often been considered species-specific. However, recent evidence suggests that this phenomenon can be strain-specific, even in strains sharing the same functional respiratory pathways, thereby implying subtle regulatory mechanisms. On this basis, I argue that induction of biofilm formation by sensing and respiration of electron acceptors might direct subgroups of redox-specialized strains to occupy certain niches. A palette of respiration and electron-transfer-mediated microbial social interactions within biofilms may broaden ecological opportunities. The strain specificity of this phenomenon represents an important opportunity to identify key molecular mechanisms and their ecophysiological significance, which in turn may lay the ground for applications in areas ranging from biotechnology to the prevention of antimicrobial resistance.}, } @article {pmid36074405, year = {2022}, author = {Silva, SMD and Ramos, BA and Sá, RAQC and Silva, MVD and Correia, MTS and Oliveira, MBM}, title = {Investigation of factors related to biofilm formation in Providencia stuartii.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {94}, number = {3}, pages = {e20210765}, doi = {10.1590/0001-3765202220210765}, pmid = {36074405}, issn = {1678-2690}, mesh = {Biofilms ; Drug Resistance, Multiple, Bacterial ; *Enterobacteriaceae Infections/microbiology ; Humans ; Providencia/genetics ; }, abstract = {Providencia stuartii is one of the Enterobacteriaceae species of medical importance commonly associated with urinary infections, which can also cause other ones, including uncommon ones, such as liver abscess and septic vasculitis. This bacterium stands out in the expression of intrinsic and acquired resistance to antimicrobials. Besides, it uses mechanisms such as biofilm for its persistence in biotic and abiotic environments. This study investigated the cellular hydrophobicity profile of clinical isolates of P. stuartii. It also analyzed genes related to the fimbrial adhesin in this species comparing with other reports described for other bacteria from Enterobacteriaceae family. The investigated isolates to form biofilm and had a practically hydrophilic cell surface profile. However, fimH and mrkD genes were not found in P. stuartii, unlike observed in other species of Enterobacteriaceae. These results show that P. stuartii has specificities regarding its potential for biofilm formation, which makes it difficult to destabilize the infectious process and increases the permanence of this pathogen in hospital units.}, } @article {pmid36074207, year = {2022}, author = {Ohno, F and Makinose, S and Tange, Y}, title = {Effectiveness of combination of heat water disinfection, continuous water circulation, and minimalized dead space for dialysis piping in maintaining ultrapure dialysis fluid and preventing biofilm formation in a central dialysis fluid delivery system.}, journal = {Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs}, volume = {}, number = {}, pages = {}, pmid = {36074207}, issn = {1619-0904}, abstract = {Various benefits have been attached to purifying the dialysis fluid used for hemodialysis therapy. The central dialysis fluid delivery system can treat approximately 50 dialysis patients simultaneously and is convenient to operate. In contrast, the dialysis fluid supply piping is complicated, and bacterial growth can cause biofilms. This study aimed to develop sustainable cleaning strategies to solve the complicated dialysis fluid piping, which is a weakness of the central dialysis fluid delivery system, and provide ultrapure dialysis fluid for a long term. Combination of heat water disinfection, continuous water circulation, and minimalized dead space in the dialysis piping were designed for a central dialysis fluid delivery system and used in a clinic for 6 years. As an index of water purification, endotoxin concentrations and microbial colony counts in reverse osmosis water and dialysis fluid were measured. In addition, we performed scanning electron microscopy of the silicon tube surface that had been used for 5 years to confirm the presence or absence of biofilm formation. For 6 years, endotoxin concentrations and microbial colonies were not detected in reverse osmosis water and dialysis fluid using the multiple-patient dialysis fluid supply equipment. The purity of the dialysis fluid was maintained. No biofilm formation was observed by scanning electron microscopy. Combination of heat water disinfection, continuous water circulation, and minimalized dead space designs for dialysis piping can supply ultrapure dialysis fluid with minimal biofilm formation in the piping in the long term.}, } @article {pmid36073834, year = {2022}, author = {Smittiset, B and Banomyong, D and Ruangsawasdi, N and Kaewprag, J}, title = {In vitro bactericidal efficacy of a new triple antibiotic paste formulation against Enterococcus faecalis biofilm.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {}, number = {}, pages = {}, doi = {10.1111/aej.12683}, pmid = {36073834}, issn = {1747-4477}, support = {DTRS-GG-2020-10//Mahidol University Faculty of Dentistry/ ; }, abstract = {The aim of this study was to evaluate the bactericidal efficacy on Enterococcus faecalis biofilm of a novel, low-concentration triple-antibiotic paste (TAP-L2) in propylene glycol/carboxymethylcellulose vehicle (VEH-2), a ready-to-use prototype, compared with two currently used products; a low-concentration (TAP-L1) and a high-concentration paste (TAP-H1) mixed in macrogol/propylene glycol vehicle (VEH-1). Sixty-two root canals were infected with E. faecalis biofilm, medicated with (a) TAP-L1, (b) TAP-L2, (c) TAP-H1, (d) VEH-1 or (e) VEH-2 (n = 10) and incubated for 21 days. Live/dead assays were performed using confocal laser scanning microscopy (CLSM), and dead bacteria (%) were calculated. The TAP-H1 group demonstrated the highest dead bacteria (67.54 ± 2.38%), which was significantly higher than the TAP-L2 and TAP-L1 groups (56.85 ± 7.11% and 54.23 ± 10.19%) (p < 0.05). The TAP groups demonstrated significantly higher dead bacteria than the VEH-1 and VEH-2 groups (47.51 ± 6.41% and 45.14 ± 8.28%) (p < 0.05). The ready-to-use TAP-L2 had antibacterial activity comparable to TAP-L1, both of which were lower than TAP-H1.}, } @article {pmid36073322, year = {2022}, author = {Tibbits, G and Mohamed, A and Gelston, S and Flurin, L and Raval, YS and Greenwood-Quaintance, K and Patel, R and Beyenal, H}, title = {Efficacy and toxicity of hydrogen peroxide producing electrochemical bandages in a porcine explant biofilm model.}, journal = {Journal of applied microbiology}, volume = {133}, number = {6}, pages = {3755-3767}, pmid = {36073322}, issn = {1365-2672}, support = {R01 AI091594/AI/NIAID NIH HHS/United States ; R01AI091594/NH/NIH HHS/United States ; R01AI091594/NH/NIH HHS/United States ; }, mesh = {Swine ; Animals ; *Staphylococcus aureus ; Hydrogen Peroxide/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Biofilms ; Bandages ; Anti-Bacterial Agents/pharmacology ; }, abstract = {AIMS: Effects of H2 O2 producing electrochemical-bandages (e-bandages) on methicillin-resistant Staphylococcus aureus colonization and biofilm removal were assessed using a porcine explant biofilm model. Transport of H2 O2 produced from the e-bandage into explant tissue and associated potential toxicity were evaluated.

METHODS AND RESULTS: Viable prokaryotic cells from infected explants were quantified after 48 h treatment with e-bandages in three ex vivo S. aureus infection models: (1) reducing colonization, (2) removing young biofilms and (3) removing mature biofilms. H2 O2 concentration-depth profiles in explants/biofilms were measured using microelectrodes. Reductions in eukaryotic cell viability of polarized and nonpolarized noninfected explants were compared. e-Bandages effectively reduced S. aureus colonization (p = 0.029) and reduced the viable prokaryotic cell concentrations of young biofilms (p = 0.029) with limited effects on mature biofilms (p > 0.1). H2 O2 penetrated biofilms and explants and reduced eukaryotic cell viability by 32-44% compared to nonpolarized explants.

CONCLUSIONS: H2 O2 producing e-bandages were most active when used to reduce colonization and remove young biofilms rather than to remove mature biofilms.

The described e-bandages reduced S. aureus colonization and young S. aureus biofilms in a porcine explant wound model, supporting their further development as an antibiotic-free alternative for managing biofilm infections.}, } @article {pmid36071959, year = {2022}, author = {Rehman, ZU and Momin, AA and Aldehaiman, A and Irum, T and Grünberg, R and Arold, ST}, title = {The exceptionally efficient quorum quenching enzyme LrsL suppresses Pseudomonas aeruginosa biofilm production.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {977673}, pmid = {36071959}, issn = {1664-302X}, abstract = {Quorum quenching (QQ) is the enzymatic degradation of molecules used by bacteria for synchronizing their behavior within communities. QQ has attracted wide attention due to its potential to inhibit biofilm formation and suppress the production of virulence factors. Through its capacity to limit biofouling and infections, QQ has applications in water treatment, aquaculture, and healthcare. Several different QQ enzymes have been described; however, they often lack the high stability and catalytic efficiency required for industrial applications. Previously, we identified genes from genome sequences of Red Sea sediment bacteria encoding potential QQ enzymes. In this study, we report that one of them, named LrsL, is a metallo-β-lactamase superfamily QQ enzyme with outstanding catalytic features. X-ray crystallography shows that LrsL is a zinc-binding dimer. LrsL has an unusually hydrophobic substrate binding pocket that can accommodate a broad range of acyl-homoserine lactones (AHLs) with exceptionally high affinity. In vitro, LrsL achieves the highest catalytic efficiency reported thus far for any QQ enzyme with a Kcat /KM of 3 × 10[7]. LrsL effectively inhibited Pseudomonas aeruginosa biofilm formation without affecting bacterial growth. Furthermore, LrsL suppressed the production of exopolysaccharides required for biofilm production. These features, and its capacity to regain its function after prolonged heat denaturation, identify LrsL as a robust and unusually efficient QQ enzyme for clinical and industrial applications.}, } @article {pmid36069446, year = {2022}, author = {Arjes, HA and Gui, H and Porter, R and Atolia, E and Peters, JM and Gross, C and Kearns, DB and Huang, KC}, title = {Fatty Acid Synthesis Knockdown Promotes Biofilm Wrinkling and Inhibits Sporulation in Bacillus subtilis.}, journal = {mBio}, volume = {13}, number = {5}, pages = {e0138822}, pmid = {36069446}, issn = {2150-7511}, support = {R35 GM131783/GM/NIGMS NIH HHS/United States ; RM1 GM135102/GM/NIGMS NIH HHS/United States ; R35 GM118061/GM/NIGMS NIH HHS/United States ; }, mesh = {*Bacillus subtilis/metabolism ; *DNA Gyrase ; Biofilms ; Fatty Acids/metabolism ; Bacterial Proteins/genetics/metabolism ; }, abstract = {Many bacterial species typically live in complex three-dimensional biofilms, yet much remains unknown about differences in essential processes between nonbiofilm and biofilm lifestyles. Here, we created a CRISPR interference (CRISPRi) library of knockdown strains covering all known essential genes in the biofilm-forming Bacillus subtilis strain NCIB 3610 and investigated growth, biofilm colony wrinkling, and sporulation phenotypes of the knockdown library. First, we showed that gene essentiality is largely conserved between liquid and surface growth and between two media. Second, we quantified biofilm colony wrinkling using a custom image analysis algorithm and found that fatty acid synthesis and DNA gyrase knockdown strains exhibited increased wrinkling independent of biofilm matrix gene expression. Third, we designed a high-throughput screen to quantify sporulation efficiency after essential gene knockdown; we found that partial knockdowns of essential genes remained competent for sporulation in a sporulation-inducing medium, but knockdown of essential genes involved in fatty acid synthesis exhibited reduced sporulation efficiency in LB, a medium with generally lower levels of sporulation. We conclude that a subset of essential genes are particularly important for biofilm structure and sporulation/germination and suggest a previously unappreciated and multifaceted role for fatty acid synthesis in bacterial lifestyles and developmental processes. IMPORTANCE For many bacteria, life typically involves growth in dense, three-dimensional communities called biofilms that contain cells with differentiated roles held together by extracellular matrix. To examine how essential gene function varies between vegetative growth and the developmental states of biofilm formation and sporulation, we created and screened a comprehensive library of strains using CRISPRi to knockdown expression of each essential gene in the biofilm-capable Bacillus subtilis strain 3610. High-throughput assays and computational algorithms identified a subset of essential genes involved in biofilm wrinkling and sporulation and indicated that fatty acid synthesis plays important and multifaceted roles in bacterial development.}, } @article {pmid36068834, year = {2022}, author = {Assefa, M and Amare, A}, title = {Biofilm-Associated Multi-Drug Resistance in Hospital-Acquired Infections: A Review.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {5061-5068}, pmid = {36068834}, issn = {1178-6973}, abstract = {Biofilm-related multi-drug resistance (MDR) is a major problem in hospital-acquired infections (HAIs) that increase patient morbidity and mortality rates and economic burdens such as high healthcare costs and prolonged hospital stay. This review focuses on the burden of bacterial biofilm in the hospital settings, their impact on the emergence of MDR in the HAIs, biofilm detection methods, recent approaches against biofilms, and future perspectives. The prevalence of biofilm-associated MDR among HAIs ranges from 17.9% to 100.0% worldwide. The predominant bacterial isolates causing HAIs in recently published studies were S. aureus, A. baumannii, K. pneumoniae, and P. aeruginosa. In addition to the use of qualitative and quantitative methods to detect biofilm formation, advanced PCR-based techniques have been performed for detecting biofilm-associated genes. Although there are suggested therapeutic strategies against biofilms, further confirmation of their efficacy for in vivo application and antibiotics targeting biofilm-associated genes/proteins to minimize treatment failure is required for the future.}, } @article {pmid36064104, year = {2022}, author = {Yang, X and Lan, W and Xie, J}, title = {Antimicrobial and anti-biofilm activities of chlorogenic acid grafted chitosan against Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {173}, number = {Pt A}, pages = {105748}, doi = {10.1016/j.micpath.2022.105748}, pmid = {36064104}, issn = {1096-1208}, mesh = {Humans ; Staphylococcus aureus ; *Chitosan/pharmacology ; Chlorogenic Acid/pharmacology ; Biofilms ; *Staphylococcal Infections/microbiology ; Anti-Bacterial Agents/pharmacology ; Microbial Sensitivity Tests ; *Anti-Infective Agents/pharmacology ; Bacteria ; }, abstract = {In this work, Chitosan-grafted-chlorogenic acid (CS-g-CA) was prepared by the carbodiimide method. The purpose of this study was to investigate the antibacterial and anti-biofilm activity of CS-g-CA against Staphylococcus aureus (S. aureus). The minimum inhibitory concentration (MIC) of CS-g-CA against S. aureus was identified as 0.625 mg/mL. S. aureus treated with 1/2 × MIC of CS-g-CA had a longer logarithmic growth phase than that of the CK group, while 1 × MIC and 2 × MIC inhibited the growth of bacteria. The damaging effect of CS-g-CA on bacterial cells was analyzed by measuring the activity of cellular antioxidant enzymes (Catalase (CAT) and Glutathione peroxidase (GSH-Px)) and intracellular enzymes (alkaline phosphatase (AKPase) and adenosine triphosphatase (ATPase)). The results of DNA gel electrophoresis illustrated that CS-g-CA disrupted the normal metabolism of bacteria. Scanning electron microscopy (SEM) results showed that S. aureus shrank and died under CS-g-CA treatment. 1 × MIC of CS-g-CA can significantly inhibit the formation of biofilms, and 1/2 × MIC of CS-g-CA control the swimming speed of S. aureus. In addition, 77.53% mature biofilm and 60.62% extracellular polysaccharide (EPS) in the mature biofilm of S. aureus were eradicated by CS-g-CA at 2 × MIC. Confocal laser scanning microscopy (CLSM) observation further confirmed these results. Therefore, CS-g-CA was an antimicrobial and antibiofilm agent to control S. aureus, which can effectively controlling the growth of S. aureus in food, thereby preventing the occurrence of food-borne diseases.}, } @article {pmid36064001, year = {2022}, author = {Ronish, LA and Sidner, B and Yu, Y and Piepenbrink, KH}, title = {Recognition of extracellular DNA by type IV pili promotes biofilm formation by Clostridioides difficile.}, journal = {The Journal of biological chemistry}, volume = {298}, number = {10}, pages = {102449}, pmid = {36064001}, issn = {1083-351X}, support = {K22 AI123467/AI/NIAID NIH HHS/United States ; P20 GM113126/GM/NIGMS NIH HHS/United States ; T32 GM107001/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; *Clostridioides difficile/genetics ; DNA/metabolism ; *Fimbriae, Bacterial/metabolism ; }, abstract = {Clostridioides difficile is a Gram-positive bacillus, which is a frequent cause of gastrointestinal infections triggered by the depletion of the gut microbiome. Because of the frequent recurrence of these infections after antibiotic treatment, mechanisms of C. difficile persistence and recurrence, including biofilm formation, are of increasing interest. Previously, our group and others found that type IV pili, filamentous helical appendages polymerized from protein subunits, promoted microcolony and biofilm formation in C. difficile. In Gram-negative bacteria, the ability of type IV pili to mediate bacterial self-association has been explained through interactions between the pili of adjacent cells, but type IV pili from several Gram-negative species are also required for natural competence through DNA uptake. Here, we report the ability of two C. difficile pilin subunits, PilJ and PilW, to bind to DNA in vitro, as well as the defects in biofilm formation in the pilJ and pilW gene-interruption mutants. Additionally, we have resolved the X-ray crystal structure of PilW, which we use to model possible structural mechanisms for the formation of C. difficile biofilm through interactions between type IV pili and the DNA of the extracellular matrix. Taken together, our results provide further insight into the relationship between type IV pilus function and biofilm formation in C. difficile and, more broadly, suggest that DNA recognition by type IV pili and related structures may have functional importance beyond DNA uptake for natural competence.}, } @article {pmid36063363, year = {2022}, author = {Díaz, PR and Romero, M and Pagnussatt, L and Amenta, M and Valverde, CF and Cámara, M and Creus, CM and Maroniche, GA}, title = {Azospirillum baldaniorum Sp245 exploits Pseudomonas fluorescens A506 biofilm to overgrow in dual-species macrocolonies.}, journal = {Environmental microbiology}, volume = {24}, number = {12}, pages = {5707-5720}, doi = {10.1111/1462-2920.16195}, pmid = {36063363}, issn = {1462-2920}, support = {BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Pseudomonas fluorescens/genetics ; *Azospirillum brasilense ; Biofilms ; Pseudomonas/genetics ; Oxygen ; }, abstract = {Biofilms are essential for plant-associated bacteria to colonize their host. In this work, we analysed the interaction of Azospirillum baldaniorum Sp245 and Pseudomonas fluorescens A506 in mixed macrocolony biofilms. We identified certain culture conditions where A. baldaniorum Sp245 exploits P. fluorescens A506 to boost its growth. Azospirillum growth increased proportionally to the initial number of pseudomonads building the biofilm, which in turn were negatively affected in their growth. Physical contact with P. fluorescens A506 was essential for A. baldaniorum Sp245 growth increase. Biofilm ultrastructure analysis revealed that Pseudomonas produces a thick structure that hosts Azospirillum cells in its interior. Additional experimentation demonstrated that Azospirillum growth boost is compromised when interacting with biofilm-deficient Pseudomonas mutants, and that a low oxygen concentration strongly induce A. baldaniorum Sp245 growth, overriding Pseudomonas stimulation. In this line, we used a microaerophilia reporter strain of A. baldaniorum Sp245 to confirm that dual-species macrocolonies contain a higher number of cells under microaerophilic conditions. Taking all the results into consideration, we propose that A. baldaniorum Sp245 can benefit from P. fluorescens A506 partnership in mixed biofilms by taking advantage of the low oxygen concentration and scaffold made up of Pseudomonas-derived matrix, to expand its growth.}, } @article {pmid36061861, year = {2022}, author = {Atiencia-Carrera, MB and Cabezas-Mera, FS and Vizuete, K and Debut, A and Tejera, E and Machado, A}, title = {Evaluation of the biofilm life cycle between Candida albicans and Candida tropicalis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {953168}, pmid = {36061861}, issn = {2235-2988}, mesh = {Animals ; Biofilms ; Candida ; *Candida albicans ; *Candida tropicalis ; Life Cycle Stages ; }, abstract = {Candida tropicalis is an emergent pathogen with a high rate of mortality associated with its biofilm formation. Biofilm formation has important repercussions on the public health system. However, little is still known about its biofilm life cycle. The present study analyzed the biofilm life cycle of Candida albicans and C. tropicalis during various timepoints (24, 48, 72, and 96 h) through biomass assays, colony-forming unit (CFU) counting, and epifluorescence and scanning electron microscopies. Our results showed a significant difference between C. albicans and C. tropicalis biofilms in each biomass and viability assay. All-time samples in the biomass and viability assays confirmed statistical differences between the Candida species through pairwise Wilcoxon tests (p < 0.05). C. albicans demonstrated a lower biomass growth but reached nearly the same level of C. tropicalis biomass at 96 h, while the CFU counting assays exhibited a superior number of viable cells within the C. tropicalis biofilm. Statistical differences were also found between C. albicans and C. tropicalis biofilms from 48- and 72-h microscopies, demonstrating C. tropicalis with a higher number of total cells within biofilms and C. albicans cells with a superior cell area and higher matrix production. Therefore, the present study proved the higher biofilm production of C. tropicalis.}, } @article {pmid36061327, year = {2022}, author = {Kadam, S and Methwani, K and Kaushik, KS}, title = {Biofilms with a Dash of Color: A Hands-On Activity for School Students to Build a Biofilm Model and Use It to Understand Antibiotic Tolerance in Biofilms.}, journal = {Journal of microbiology & biology education}, volume = {23}, number = {2}, pages = {}, pmid = {36061327}, issn = {1935-7877}, abstract = {It is increasingly recognized that microbes such as bacteria exist in communities or biofilms, both in the environment and human body. However, school biology curricula continue to focus on the free-floating form of bacterial life, with minimal descriptions of biofilms. Consequently, there is a need to introduce biofilms to school students, to not only to develop a fundamental understanding of microbial life but also to highlight the challenges posed by biofilm infections to antibiotic treatment. We have developed a hands-on activity for students to build a biofilm model and use it in comparison with a model of free-living (planktonic) bacteria, to test the role of the extracellular matrix in the antibiotic tolerance of biofilms. The activity uses simple, easy-to-obtain supplies and is designed to be conducted in an in-person or virtual format for elementary and middle school students in the age group of 6 to 13 years. We conducted the activity in virtual mode (via Zoom) for 59 school students across India, and we present feedback and acquired knowledge that could be used to execute and adapt this accessible and engaging science experience.}, } @article {pmid36060772, year = {2022}, author = {Guo, J and Zhu, J and Zhao, T and Sun, Z and Song, S and Zhang, Y and Zhu, D and Cao, S and Deng, X and Chai, Y and Sun, Y and Maratbek, S and Chen, C and Liu, L and Zhang, H}, title = {Survival characteristics and transcriptome profiling reveal the adaptive response of the Brucella melitensis 16M biofilm to osmotic stress.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {968592}, pmid = {36060772}, issn = {1664-302X}, abstract = {Brucella can inhabit hostile environments, including osmotic stress. How Brucella responds collectively to osmotic stress is largely unexplored, particularly in spatially structured communities such as a biofilm. To gain insight into this growth mode, we set out to characterize the Brucella melitensis 16M biofilm, describe its phenotype, and carry out a comparative transcriptomic analysis between biofilms under osmotic stress and control conditions. We determined that the bacteria challenged with 1.5 M NaCl had a reduced ability to aggregate and form clumps and develop a biofilm; however, the salt stress promoted the release of the outer membrane vesicles from the biofilm. Together with the genotypical response to osmotic stress, we identified 279 differentially expressed genes in B. melitensis 16M grown under osmotic conditions compared with control conditions; 69 genes were upregulated and 210 downregulated. Under osmotic stress, the main changed genes of biofilm were predicted to be involved in flagellar assembly, cell envelope, translation, small RNA regulation, transport and binding proteins, and energy metabolism. In addition, the ABC transporter was enriched in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. We highlight 12 essential ABC transporter genes associated with a bacterial response to osmotic stress at the biofilm stage, including one specific locus, BME_RS12880, mediating betaine accumulation in biofilms to eliminate osmotic stress. The current study results can help researchers gain insights into B. melitensis 16M biofilm adaptation to osmotic stress and provide information for developing intervention strategies to control Brucella.}, } @article {pmid36060142, year = {2022}, author = {Odularu, AT and Afolayan, AJ and Sadimenko, AP and Ajibade, PA and Mbese, JZ}, title = {Multidrug-Resistant Biofilm, Quorum Sensing, Quorum Quenching, and Antibacterial Activities of Indole Derivatives as Potential Eradication Approaches.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {9048245}, pmid = {36060142}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Indoles/pharmacology ; *Quorum Sensing ; }, abstract = {Challenges encountered in relapse of illness caused by resistance of microorganisms to antimicrobial agents (drugs) are due to factors of severe stress initiated by random use of antibiotics and insufficient beneficial approaches. These challenges have resulted to multiple drug resistance (MDR) and, subsequently, biofilm formation. A type of intercellular communication signal called quorum sensing (QS) has been studied to cause the spread of resistance, thereby enabling a formation of stable community for microorganisms. The QS could be inhibited using QS inhibitors (QSIs) called quorum-quenching (QQ). The QQ is an antibiofilm agent. Indole derivatives from plant sources can serve as quorum-quenching eradication approach for biofilm, as well as a promising nontoxic antibiofilm agent. In other words, phytochemicals in plants help to control and prevent biofilm formation. It could be recommended that combination strategies of these indoles' derivatives with antibiotics would yield enhanced results.}, } @article {pmid36059509, year = {2022}, author = {Khamwong, M and Phanthanawiboon, S and Salao, K and Chareonsudjai, S}, title = {Burkholderia pseudomallei biofilm phenotypes confined but surviving in neutrophil extracellular traps of varying appearance.}, journal = {Frontiers in immunology}, volume = {13}, number = {}, pages = {926788}, pmid = {36059509}, issn = {1664-3224}, mesh = {Biofilms ; *Burkholderia pseudomallei ; *Extracellular Traps ; Humans ; *Melioidosis ; Phenotype ; }, abstract = {Melioidosis is a fatal infectious disease caused by Burkholderia pseudomallei. Complications following treatment are usually due to antibiotic resistance and relapse is mainly caused by B. pseudomallei biofilm. Although the release of neutrophil extracellular traps (NETs) is crucial to capture and eliminate bacterial pathogens, to date response of NETs to B. pseudomallei biofilm is poorly understood. Here we compare the NETs produced by neutrophils in response to B. pseudomallei H777 (a biofilm-producing strain containing the bpsl0618 gene), a biofilm-defect strain lacking this gene (B. pseudomallei M10) and a bpsl0618 biofilm-complemented strain, B. pseudomallei C17, in which function of bpsl0618 was restored. Co-cultivation of these strains with healthy human neutrophils at MOI 10 with or without cytochalasin D demonstrated that H777 significantly resisted neutrophil-mediated killing and non-phagocytotic mechanisms compared to M10 (p < 0.0001). Three distinct morphotypes of NETs were seen: "aggregated", "spiky" and "cloudy". These were induced in different proportions by the different bacterial strains. All types of NETs were shown to confine all B. pseudomallei strains. Strains H777 and C17 could stimulate production of twice as much extracellular DNA (234.62 ng/mL and 205.43 ng/mL, respectively) as did M10 (111.87 ng/mL). Cells of H777 and C17 were better able to survive in the presence of neutrophil killing mechanisms relative to M10 (p < 0.0001) and NET formation (p < 0.0001 and 0.05). These findings suggest that NET stimulation was insufficient to eradicate B. pseudomallei H777 and C17 despite their possession of bpsl0618, a sugar-transferase gene associated with biofilm formation ability. Our findings demonstrate that B. pseudomallei biofilm phenotype may be a key factor in assisting pathogens to escape killing by neutrophils. This work provides a better understanding of how B. pseudomallei biofilm-associated infections induce and survive NET formation, resulting in bacterial persistence and increased severity of disease.}, } @article {pmid36058016, year = {2022}, author = {Cai, D and Zhang, Z and Feng, Z and Song, J and Zeng, X and Tu, Y and Zhao, S and Luo, X and Sun, C and Yang, Y and Liu, X and Zou, Q and Zeng, H and Sun, H}, title = {A lipophilic chitosan-modified self-nanoemulsifying system influencing cellular membrane metabolism enhances antibacterial and anti-biofilm efficacy for multi-drug resistant Pseudomonas aeruginosa wound infection.}, journal = {Biomaterials advances}, volume = {140}, number = {}, pages = {213029}, doi = {10.1016/j.bioadv.2022.213029}, pmid = {36058016}, issn = {2772-9508}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Membrane ; *Chitosan/pharmacology ; Humans ; Proteomics ; Pseudomonas aeruginosa ; *Wound Infection/drug therapy ; }, abstract = {Wound infections, especially infections with multidrug-resistant bacteria, are a serious public health issue worldwide. In addition, the accumulation microbial biofilm of multidrug-resistant Pseudomonas aeruginosa increases the risk and physically obstruct its healing activity at the wound site. Therefore, the development of an eminent agent to control wound infection is urgently needed. Here, we report a novel chitosan (a natural biological macromolecule)-modified self-nanoemulsifying system (CSN) with lipophilic chlorhexidine acetate (CAA, a poorly water-soluble agent) that was designed and prepared using low-energy emulsification methods. We found that CSN displays better antibacterial efficacy, which occurs more quickly than its aqueous solution, in destroying the structure of the bacterial cell membrane and promoting the leakage of nucleic acids, proteins, K[+], and Mg[2+] from Pseudomonas aeruginosa cells. Importantly, CSN also accelerates skin wound healing after Pseudomonas aeruginosa infection by inhibiting biofilm formation and eradicating mature biofilms. Moreover, the proteomic results suggested that CSN altered membrane permeability and cellular membrane metabolism, allowing more drug molecules to enter the cytosol. Based on these results, this lipophilic self-nanoemulsifying system may be applied in the treatment of skin wounds caused by multidrug-resistant bacteria, especially Pseudomonas aeruginosa.}, } @article {pmid36057364, year = {2022}, author = {Pereira, F and de Annunzio, SR and Lopes, TA and de Oliveira, KT and Cilli, EM and Barbugli, PA and Fontana, CR}, title = {Efficacy of the combination of P5 peptide and photodynamic therapy mediated by bixin and chlorin-e6 against Cutibacterium acnes biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103104}, doi = {10.1016/j.pdpdt.2022.103104}, pmid = {36057364}, issn = {1873-1597}, mesh = {*Photochemotherapy/methods ; *Porphyrins/pharmacology ; Biofilms ; Propionibacterium acnes ; *Anti-Infective Agents/pharmacology ; Bacteria ; Peptides/pharmacology ; Photosensitizing Agents/pharmacology ; }, abstract = {In this study, the action of antimicrobial peptide (AMP) P5 and antimicrobial photodynamic therapy (aPDT) mediated by bixin and chlorin-e6 (Ce6) on Cutibacterium acnes (C. acnes) in planktonic phase and biofilm were evaluated both as monotherapies and combined therapies. Microbial viability after treatments were quantified by colony-forming units per milliliter of the sample (CFU/mL) and have demonstrated that all treatments employed exerted bactericidal activity, reducing the microbial load by more than 3 log10 CFU/mL, also demonstrating for the first time in the literature the antimicrobial photodynamic effect of bixin that occurs mostly through type I mechanism which was proved by the quantification of superoxide anion production. Bacterial biofilm was completely eliminated only after its exposure to aPDT mediated by this PS, however, Ce6 proved to be a more efficient PS, considering that most of the photodynamic effect of bixin- aPDT was exerted by excitation of the endogenous C porphyrins of C. acnes with blue light. The combination of P5 with Ce6-aPDT showed a synergistic effect on the bacterial biofilm with a reduction in microbial load by more than 10 log10 CFU/mL, in which the ability of P5 to permeabilize the polymeric extracellular matrix of the biofilm explains the obtained results, with greater internalization of the PS as shown by the Confocal Laser Scanning Microscopy. One-way ANOVA (Analysis of Variance) with Tukey's post-test and two-way ANOVA with Bonferroni's post-test were used to compare the values of continuous variables between the control group and the treatment groups.}, } @article {pmid36056994, year = {2022}, author = {Zhu, W and Ding, Y and Huang, C and Wang, J and Wang, J and Wang, X}, title = {Genomic characterization of a novel bacteriophage STP55 revealed its prominent capacity in disrupting the dual-species biofilm formed by Salmonella Typhimurium and Escherichia coli O157: H7 strains.}, journal = {Archives of microbiology}, volume = {204}, number = {10}, pages = {597}, pmid = {36056994}, issn = {1432-072X}, support = {2017YFC1600100//National Key R&D Program of China/ ; 31772054//Natural Science Foundation of China/ ; }, mesh = {*Bacteriophages/genetics ; Biofilms ; *Escherichia coli O157/genetics ; Food Microbiology ; Genomics ; Phylogeny ; Salmonella typhimurium/genetics ; }, abstract = {Salmonella and Escherichia coli are important foodborne pathogens, forming bacterial biofilms that contribute to their virulence, antimicrobial resistance, and survival on surfaces. Broad lytic phages are promising alternatives to conventional technologies for pathogen biocontrol and reducing biofilms. Herein, we isolated and characterized a novel polyvalent phage STP55 that not only lyse some serotypes of Salmonella, but also some E. coli strains. It had a wide range of pH (4-12) and thermal (30-60 °C) tolerances. The latent time was determined to be 10 min in the one-step growth experiment. Morphological observations by transmission electron microscopy and phylogenetic analysis using terminase gene classified STP55 to family Ackermannviridae in the order Caudovirales, with a complex tail structure. The genome was found to comprise 157,708 bp double-stranded DNA, with 44.57% GC content, 207 predicted ORFs and with no genes associated with antibiotic resistance, toxins, lysogeny, and virulence factors. Particularly, phage STP55 was able to inhibit single- and dual-species biofilms formation by S. Typhimurium ATCC 14028 and E. coli O157: H7, with a reduction percentage of 51.0%, 47.8% and 52.8%, respectively. Moreover, more than 65.0%, 72.9% and 46.2% of an established, single- and dual-species biofilms by S. Typhimurium ATCC 14028 and E. coli O157: H7 were removed after 8 h exposure to the phage STP55, respectively. The elimination effect of STP55 on dual-species biofilm formed on lettuce was further observed by SEM. Overall, our results demonstrated that STP55 is a promising antimicrobial against Salmonella and E. coli.}, } @article {pmid36056708, year = {2022}, author = {Yang, K and Hai, L and Wang, Z and Li, H and Yi, W and Luo, Y and Li, J and Deng, L and He, D}, title = {A biofilm microenvironment-responsive one-for-all bactericidal nanoplatform for photothermal-augmented multimodal synergistic therapy of pathogenic bacterial biofilm infection.}, journal = {Journal of materials chemistry. B}, volume = {10}, number = {38}, pages = {7744-7759}, doi = {10.1039/d2tb01200f}, pmid = {36056708}, issn = {2050-7518}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacterial Infections ; Biofilms ; Glutathione/pharmacology ; Humans ; Hydrogen Peroxide/pharmacology ; *Hyperthermia, Induced ; Methylene Blue/pharmacology ; Polyethylene Glycols/pharmacology ; *Zinc Oxide/pharmacology ; }, abstract = {Multimodal synergistic bactericidal agents display great potential for fighting biofilm infections. However, the rational design of biofilm microenvironment (BME)-activatable therapeutic agents with excellent specificities, effective eradications and minimal side effects remains a great challenge. Herein, we show a BME-responsive one-for-all bactericidal nanoplatform consisting of Fe[3+]-doped polydopamine (Fe/PDA)-capped ZnO nanoparticles with a successive assembly of methylene blue (MB) and poly(ethylene glycol) (PEG). In an acidic BME (pH 5.5), the constructed nanoagent (ZnPMp) can realize the co-delivery of dual metal ions (Zn[2+] and Fe[3+]) and MB, and the latter shows an activated photodynamic antibacterial activity when irradiated with 635 nm laser. Zn[2+] produced from acid-sensitive dissolution of ZnO is an effective chemical antibacterial agent. Additionally, the released Fe[3+] is reduced to Fe[2+] by glutathione (GSH) overexpressed in the BME to generate Fe[2+]/Fe[3+] redox couples, which exhibit Fenton catalytic activity to convert endogenous H2O2 to hydroxyl radicals (˙OH) for chemodynamic sterilization and GSH depletion ability to improve ˙OH-induced oxidative damage. Interestingly, the hyperthermia caused by the Fe/PDA layer assisted with 808 nm laser can damage directly bacterial cells, accelerate the release of Zn[2+], Fe[3+]and MB, and promote the catalytic activity of Fe[2+]/Fe[3+] redox couples for photothermal-augmented multimodal antibiofilm therapy. With the help of dual lasers, ZnPMp displays the broad-spectrum antibacterial effect, inhibits effectively the formation of biofilms, and more importantly eliminates bacteria deep in mature biofilms. In addition, ZnPMp can be used to treat biofilm-related infections in vivo with excellent therapeutic performance and minimal toxicity. Overall, the developed ZnPMp may serve as a potential nano-antibacterial agent for intensive anti-infective therapy.}, } @article {pmid36056144, year = {2022}, author = {Manna, AC and Leo, S and Girel, S and González-Ruiz, V and Rudaz, S and Francois, P and Cheung, AL}, title = {Teg58, a small regulatory RNA, is involved in regulating arginine biosynthesis and biofilm formation in Staphylococcus aureus.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {14963}, pmid = {36056144}, issn = {2045-2322}, support = {RO1 AI146116/NH/NIH HHS/United States ; }, mesh = {Arginine/metabolism ; Bacterial Proteins/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Humans ; *RNA, Small Untranslated/genetics/metabolism ; *Staphylococcal Infections/genetics ; Staphylococcus aureus/physiology ; Trans-Activators/metabolism ; }, abstract = {Staphylococcus aureus adapts to different environments by sensing and responding to diverse environmental cues. The responses are coordinately regulated by regulatory proteins, and small regulatory RNAs at the transcriptional and translational levels. Here, we characterized teg58, a SarA repressed sRNA, using ChIP-Seq and RNA-Seq analysis of a sarA mutant. Phenotypic and genetic analyses indicated that inactivation of teg58 led to reduced biofilm formation in a process that is independent of SarA, agr, PIA, and PSMs. RNA-Seq analysis of teg58 mutant revealed up-regulation of arginine biosynthesis genes (i.e., argGH) as well as the ability of the mutant to grow in a chemical defined medium (CDM) lacking L-arginine. Exogenous L-arginine or endogenous induction of argGH led to decreased biofilm formation in parental strains. Further analysis in vitro and in vivo demonstrated that the specific interaction between teg58 and the argGH occurred at the post-transcriptional level to repress arginine synthesis. Biochemical and genetic analyses of various arginine catabolic pathway genes demonstrated that the catabolic pathway did not play a significant role in reduced biofilm formation in the teg58 mutant. Overall, results suggest that teg58 is a regulatory sRNA that plays an important role in modulating arginine biosynthesis and biofilm formation in S. aureus.}, } @article {pmid36055541, year = {2022}, author = {Wang, X and Yang, H and Liu, X and Wang, J}, title = {Formation mechanisms and assembly patterns of anammox biofilm induced by carrier type: Novel insights based on low-strength wastewater treatment.}, journal = {Bioresource technology}, volume = {362}, number = {}, pages = {127863}, doi = {10.1016/j.biortech.2022.127863}, pmid = {36055541}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Anaerobiosis ; Bacteria/genetics/metabolism ; Biofilms ; *Bioreactors/microbiology ; Nitrogen/metabolism ; Oxidation-Reduction ; Sewage ; *Water Purification ; }, abstract = {The morphological structure, properties, microbial community and function of anammox biofilms induced by large-pore carriers (Bls), small-pore carriers, filament carriers and non-carriers (Bn) in low-strength wastewater were comprehensively studied. The carriers promoted biomass accumulation and agglomeration, with Bls demonstrating the highest biomass proportion of 0.76, the highest specific anammox activity (0.41 kgN/(kgVSS·d)[-1]) and the largest aggregates. Hydraulic shearing stimulated Bn to secrete most extracellular polymeric substances and capture more inorganic ions for enhanced strength. Metagenomic sequencing showed that the four biofilms shared a common core flora, but differed in cross-metabolism. The proportion of the functional bacterium Candidatus Brocadia was highest in Bls, while the increase in heterotrophic bacteria in Bn supported stronger metabolic capacity. Finally, the proposed anisotropic or isotropic carrier structure was identified as the key to generating "uniform development" and "central development" models. This study is helpful for understanding the anammox aggregation mechanism and carrier optimization.}, } @article {pmid36053379, year = {2022}, author = {Üreyen Esertaş, ÜZ and Kara, Y and Kiliç, AO and Kolayli, S}, title = {A comparative study of antimicrobial, anti-quorum sensing, anti-biofilm, anti-swarming, and antioxidant activities in flower extracts of pecan (Carya illinoinensis) and chestnut (Castanea sativa).}, journal = {Archives of microbiology}, volume = {204}, number = {9}, pages = {589}, pmid = {36053379}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Antifungal Agents/pharmacology ; Antioxidants/pharmacology ; Biofilms ; *Carya ; Chromobacterium ; Flowers ; Plant Extracts/chemistry/pharmacology ; Pseudomonas aeruginosa ; }, abstract = {Antibiotic resistance, which has increased rapidly in recent years because of uncontrolled and unconscious antibiotic consumption, poses a major threat to public health. The inadequacy of existing antibiotics has increased the need for new, effective, and less toxic antibiotic raw materials or antibiotic derivatives. Pecan (Carya illinoinensis) and Chestnut (Castanea sativa) flowers possess abundant pollen contents and exhibit similar morphological features. The purpose of this study was to compare these two flower extracts in terms of their antimicrobial and antioxidant activities. Total phenolic content, total flavonoid contents, and phenolic components were also analyzed in aquatic and ethanolic extracts. Antioxidant activities were measured using ferric reducing/antioxidant capacity (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Antimicrobial and antifungal activities were compared by means of agar diffusion tests against bacteria including Staphylococcus aureus, Bacillus cereus, Mycobacterium smegmatis, Acinetobacter haemolyticus, and Chromobacterium violaceum, and the yeasts Candida albicans and Candida parapsilosis. Anti-quorum sensing (anti-QS), anti-biofilm, and anti-swarming (SW) activities were also studied against Chromobacterium violaceum ATCC 31532, Chromobacterium violaceum ATCC 12472, and Pseudomonas aeruginosa PA01, respectively. Both extracts were rich in ellagic acid and gallic acid and exhibited similar antioxidant properties. Both flower extracts exhibited high antimicrobial and antifungal activities as well as anti-biofilm, anti-QS, and anti-SW activities.}, } @article {pmid36050412, year = {2022}, author = {Saadati, F and Shahryari, S and Sani, NM and Farajzadeh, D and Zahiri, HS and Vali, H and Noghabi, KA}, title = {Effect of MA01 rhamnolipid on cell viability and expression of quorum-sensing (QS) genes involved in biofilm formation by methicillin-resistant Staphylococcus aureus.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {14833}, pmid = {36050412}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Survival ; Glycolipids ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Quorum Sensing ; }, abstract = {A group of biosurfactants, called rhamnolipids, have been shown to have antibacterial and antibiofilm activity against multidrug-resistant bacteria. Here, we examined the effect of rhamnolipid biosurfactants extracted from Pseudomonas aeruginosa MA01 on cell growth/viability, biofilm formation, and membrane permeability of methicillin-resistant Staphylococcus aureus (MRSA) ATCC6538 bacterial cells. The results obtained from flow cytometry analysis showed that by increasing the concentration of rhamnolipid from 30 to 120 mg/mL, the cell viability decreased by about 70%, and the cell membrane permeability increased by approximately 20%. In fact, increasing rhamnolipid concentration was directly related to cell membrane permeability and inversely related to cell survival. Microtiter plate biofilm assay and laser scanning confocal microscopy analysis revealed that rhamnolipid, at a concentration of 60 mg/mL, exerts a reducing effect on the biofilm formation of Staphylococcus aureus. Real-time PCR analysis for monitoring the relative changes in the expression of agrA, agrC, icaA, and icaD genes involved in biofilm formation and related to the quorum-sensing pathway after treatment with rhamnolipid indicated a reduced expression level of these genes, as well as sortase A gene. The results of the present study deepen our knowledge regarding the use of microbial natural products as promising candidates for therapeutic applications.}, } @article {pmid36048880, year = {2022}, author = {Arafa, SH and Alshehri, WA and Organji, SR and Elbanna, K and Obaid, NA and Aldosari, MS and Asiri, FH and Ahmad, I and Abulreesh, HH}, title = {Antimicrobial Resistance, Virulence Factor-Encoding Genes, and Biofilm-Forming Ability of Community-Associated Uropathogenic Escherichia coli in Western Saudi Arabia.}, journal = {Polish journal of microbiology}, volume = {71}, number = {3}, pages = {325-339}, pmid = {36048880}, issn = {2544-4646}, mesh = {Agar ; Ampicillin ; Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Drug Resistance, Bacterial ; Ertapenem ; *Escherichia coli Infections/epidemiology ; Female ; Imipenem ; Meropenem ; Norfloxacin ; Saudi Arabia/epidemiology ; Sheep ; *Urinary Tract Infections/epidemiology ; *Uropathogenic Escherichia coli/genetics ; Virulence Factors/genetics ; }, abstract = {To explore the prevalence of multidrug-resistant community-associated uropathogenic Escherichia coli (UPEC) and their virulence factors in Western Saudi Arabia. A total of 1,000 urine samples were examined for the presence of E. coli by selective plating on MacConkey, CLED, and sheep blood agar. Antimicrobial susceptibility patterns were determined using Vitek[®] 2 Compact (MIC) and the disc diffusion method with Mueller-Hinton agar. Genes encoding virulence factors (kpsMTII, traT, sat, csgA, vat, and iutA) were detected by PCR. The overall prevalence of UTI-associated E. coli was low, and a higher prevalence was detected in samples of female origin. Many of the isolates exhibited resistance to norfloxacin, and 60% of the isolates showed resistance to ampicillin. No resistance to imipenem, meropenem, or ertapenem was detected. In general, half of the isolates showed multiple resistance patterns. UPEC exhibited a weak ability to form biofilms, where no correlation was observed between multidrug resistance and biofilm-forming ability. All uropathogenic E. coli isolates carried the kpsMTII, iutA, traT, and csgA genes, whereas the low number of the isolates harbored the sat and vat genes. The diversity of virulence factors harbored by community-associated UPEC may render them more virulent and further explain the recurrence/relapse cases among community-associated UITs. To the best of our knowledge, this study constitutes the first exploration of virulence, biofilm-forming ability, and its association with multidrug resistance among UPEC isolates in Saudi Arabia. Further investigations are needed to elucidate the epidemiology of community-associated UPEC in Saudi Arabia.}, } @article {pmid36047990, year = {2022}, author = {Zhao, J and Zheng, M and Su, Z and Liu, T and Li, J and Guo, J and Yuan, Z and Hu, S}, title = {Selective Enrichment of Comammox Nitrospira in a Moving Bed Biofilm Reactor with Sufficient Oxygen Supply.}, journal = {Environmental science & technology}, volume = {56}, number = {18}, pages = {13338-13346}, doi = {10.1021/acs.est.2c03299}, pmid = {36047990}, issn = {1520-5851}, mesh = {*Ammonia ; *Ammonium Compounds ; Bacteria/genetics ; Biofilms ; Bioreactors ; In Situ Hybridization, Fluorescence ; Nitrification ; Oxidation-Reduction ; Oxygen ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Wastewater/microbiology ; }, abstract = {The recent discovery of comammox (complete ammonia oxidation) Nitrospira has upended the long-held nitrification paradigm. Although comammox Nitrospira have been identified in wastewater treatment systems, the conditions for their dominance over canonical ammonia oxidizers remain unclear. Here, we report the dominance of comammox Nitrospira in a moving bed biofilm reactor (MBBR) fed with synthetic mainstream wastewater. Integrated 16S rRNA gene amplicon sequencing, fluorescence in situ hybridization (FISH), and metagenomic sequencing methods demonstrated the selective enrichment of comammox bacteria when the MBBR was operated at a dissolved oxygen (DO) concentration above 6 mg O2/L. The dominance of comammox Nitrospira over canonical ammonia oxidizers (i.e., Nitrosomonas) was attributed to the low residual ammonium concentration (0.02-0.52 mg N/L) formed in the high-DO MBBR. Two clade A comammox Nitrospira were identified, which are phylogenetically close to Candidatus Nitrospira nitrosa. Interestingly, cryosectioning-FISH showed these two comammox species spatially distributed on the surface of the biofilm. Moreover, the ammonia-oxidizing activity of comammox Nitrospira-dominated biofilms was susceptible to the oxygen supply, which dropped by half with the DO concentration decrease from 6 to 2 mg O2/L. These features collectively suggest a low apparent oxygen affinity for the comammox Nitrospira-dominated biofilms in the high-DO nitrifying MBBR.}, } @article {pmid36047500, year = {2022}, author = {Wang, R and Wang, Y and Lei, Z and Hao, L and Jiang, L}, title = {Glucosyltransferase-modulated Streptococcus mutans adhesion to different surfaces involved in biofilm formation by atomic force microscopy.}, journal = {Microbiology and immunology}, volume = {66}, number = {11}, pages = {493-500}, doi = {10.1111/1348-0421.13025}, pmid = {36047500}, issn = {1348-0421}, mesh = {*Streptococcus mutans/metabolism ; Microscopy, Atomic Force ; *Glucosyltransferases/genetics/metabolism ; Biofilms ; Bacterial Adhesion ; }, abstract = {Biofilm on dental restorative materials is an important determinant in the etiology of secondary caries development. Formation of biofilm involves adhesion of bacteria onto substrate, bacterial cell, and biofilm surfaces. Glucosyltransferase B and C (GtfB and GtfC) are essential factors for regulation of Streptococcus mutans biofilm formation, but the mechanisms involving different kinds of bacterial adhesion still lack detailed description. In this study, nanoscale adhesion force measurement was performed using atomic force microscopy. Bacteria-coated cantilevers were used to probe S. mutans adhesion to substrates, bacterial cells, and early biofilms. Two representative dental materials, glass ionomer cement (GIC) and composite resin, served as substrates. It was found that deletion of gtfB and gtfC genes both reduced adhesion forces of S. mutans toward substrate and bacterial cell surfaces (P < 0.05). Notably, reduction of the gtfB gene remarkably decreased bacterial adhesion to biofilm surfaces (P < 0.05), while gtfC showed no obvious effect during this stage. Biofilms cultured on GIG further decreased cell-biofilm adhesion, compared with those on resin (P < 0.05). Confocal fluorescence images and scanning electron microscopy images showed that deletion of gtfB lead to reduced microcolony formation and less production of exopolysaccharides (EPSs) in the biofilm, and after bacterial culturing on GIC, the EPS content was further decreased. Our findings suggest that EPSs mainly mediate bacterial adhesion to early biofilm surface. Deletion of gtfB and coculture with GIC could significantly reduce the cell-biofilm adhesion, which is probably through decreasing of EPS production. gtfB exerts a critical role in the bacterial adhesion for the whole process of biofilm development, while gtfC possibly works only in the early stages.}, } @article {pmid36046695, year = {2022}, author = {Rösing, CK and Garduño, E and Bussadori, SK and Zerón, A and Soares, PV and Saadia, M and Villar, CC}, title = {Powered Toothbrushes: An Opportunity for Biofilm and Gingival Inflammation Control.}, journal = {International journal of dentistry}, volume = {2022}, number = {}, pages = {6874144}, pmid = {36046695}, issn = {1687-8728}, abstract = {The present review aimed at a broad investigation on the potential of powered as compared to manual toothbrushes in different aspects of clinical dentistry. Studies evaluating plaque and gingival inflammatory parameters were included, as well as those that investigated adverse effects. Emphasis was given separately to adults, youngsters, special-needs patients, and those under fixed orthodontic therapy. In general, comparisons favored powered toothbrushes. In summary, approximately 68% of the included studies, in terms of plaque/gingival inflammation in adults, presented better results for powered toothbrushes. In children and special-needs populations, approximately 40% of the included studies favored powered toothbrushes for plaque/gingival inflammation, and none favored manual ones. In orthodontic individuals, 50% of the studies also demonstrated a better effect of powered toothbrushes on plaque and gingival inflammation. All included studies that assessed adverse events did not demonstrate a difference in these effects when comparing manual vs. powered toothbrushes. It is concluded that the use of powered toothbrushes is an opportunity to enhance patterns of plaque control and associated gingival inflammation.}, } @article {pmid36040237, year = {2022}, author = {Pathirajah, JP and Balamurugan, S and Arvaj, L and Weiss, J and Barbut, S}, title = {Influence of Different Stainless Steel Finishes on Biofilm Formation by Listeria monocytogenes.}, journal = {Journal of food protection}, volume = {85}, number = {11}, pages = {1584-1593}, doi = {10.4315/JFP-22-112}, pmid = {36040237}, issn = {1944-9097}, support = {2000/CU/CSP VA/United States ; 2323//Baden-Württemberg Stiftung/ ; }, mesh = {*Listeria monocytogenes ; Stainless Steel/analysis ; Food Microbiology ; Bacterial Adhesion ; Colony Count, Microbial ; Biofilms ; }, abstract = {ABSTRACT: Biofilm formation of Listeria monocytogenes on stainless steel, a widely used abiotic surface in the food processing industry, was investigated by focusing on the attachment tendency and behavior of L. monocytogenes 08-5578 on eight different stainless steel surfaces: glass bead blasted (rough and fine), deburred (Timesaver), drum deburred, pickled, pickled and drum polished, electrolytic polished, and cold rolled (untreated control). The aim was to see whether there are finishes with significantly lower bacterial attachment. Surface roughness data (measured via four roughness parameters), determined by interferometry, was also compared with the number of adhering cells to detect possible correlations. Cultivation of L. monocytogenes biofilms was carried out using a CDC biofilm reactor with 1% tryptic soy broth set at 20°C for 4, 8, and 24 h. In addition, a cultivation trial was run with continuous nutrient flow (1% tryptic soy broth, 6.2 mL/min) for 24 h. Eight-hour results showed a significant difference (P < 0.05) in biofilm cell counts in biofilms between the glass bead-blasted surfaces (3.23 and 3.26 log CFU/cm2 for the fine and rough, respectively) and deburred (Timesaver) surface (2.57 log CFU/cm2), between drum deburred and deburred (Timesaver) surface (3.41 versus 2.57 log CFU/cm2), and between drum deburred and pickled surface (3.41 versus 2.77 log CFU/cm2). Data gained after 4-h, 24-h, and 24-h plus an additional 24-h continuous flow cultivation showed no significant difference in attachment among surfaces. No correlation between roughness data and attachment was found after all four incubation times, suggesting that roughness values, at these ranges, are insufficient in determining the surfaces' affinity to bacteria. Overall, this study suggests that roughness values cannot be used to predict the degree of L. monocytogenes attachment to a specific stainless steel surface.}, } @article {pmid36038607, year = {2022}, author = {Highmore, CJ and Melaugh, G and Morris, RJ and Parker, J and Direito, SOL and Romero, M and Soukarieh, F and Robertson, SN and Bamford, NC}, title = {Translational challenges and opportunities in biofilm science: a BRIEF for the future.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {68}, pmid = {36038607}, issn = {2055-5008}, support = {BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Biofilms ; *Wastewater ; Water ; }, abstract = {Biofilms are increasingly recognised as a critical global issue in a multitude of industries impacting health, food and water security, marine sector, and industrial processes resulting in estimated economic cost of $5 trillion USD annually. A major barrier to the translation of biofilm science is the gap between industrial practices and academic research across the biofilms field. Therefore, there is an urgent need for biofilm research to notice and react to industrially relevant issues to achieve transferable outputs. Regulatory frameworks necessarily bridge gaps between different players, but require a clear, science-driven non-biased underpinning to successfully translate research. Here we introduce a 2-dimensional framework, termed the Biofilm Research-Industrial Engagement Framework (BRIEF) for classifying existing biofilm technologies according to their level of scientific insight, including the understanding of the underlying biofilm system, and their industrial utility accounting for current industrial practices. We evidence the BRIEF with three case studies of biofilm science across healthcare, food & agriculture, and wastewater sectors highlighting the multifaceted issues around the effective translation of biofilm research. Based on these studies, we introduce some advisory guidelines to enhance the translational impact of future research.}, } @article {pmid36038086, year = {2022}, author = {Zhan, X and Tan, Y and Cheng, X and Wang, R and Guo, D and Wang, M and Su, R and Chang, Y and Xia, X and Shi, C}, title = {Effects of cinnamaldehyde against planktonic bacteria and biofilm formation of Shigella flexneri.}, journal = {Microbial pathogenesis}, volume = {171}, number = {}, pages = {105741}, doi = {10.1016/j.micpath.2022.105741}, pmid = {36038086}, issn = {1096-1208}, mesh = {Acrolein/analogs & derivatives ; Adenosine Triphosphate/metabolism ; Anti-Bacterial Agents/metabolism/pharmacology ; Bacteria ; Biofilms ; Gentian Violet ; Microbial Sensitivity Tests ; *Plankton ; Reactive Oxygen Species/metabolism ; *Shigella flexneri ; }, abstract = {Cinnamaldehyde (CA) has demonstrated anti-inflammatory, anti-tumor and anti-cancer activities; Its antimicrobial and antibiofilm actions against Shigella flexneri, on the other hand, have not been investigated. Sh. flexneri is a gram-negative foodborne pathogen that can be widely found in nature and some industrial production environments. In this current research, our aim was to examine the influences of CA on planktonic bacteria and biofilm formation. The minimum inhibitory concentration (MIC) of CA against Sh. flexneri strain was 100 μg/mL, while bacteria treated with CA showed a longer lag phase compared with the untreated control. CA effectively inactivated the Sh. flexneri in LB broth and fresh lettuce juice. CA treatment resulted in cell membrane permeability changes and dysfunction, as proven by cell membrane depolarization, decreased intracellular ATP concentration. In addition, CA was also discovered to increase the level of reactive oxygen species (ROS) in cells, and induce morphological changes in cells. Crystal violet staining showed that the biomass of biofilm was decreased significantly with CA in 24 h. Light microscopy and field emission scanning electron microscopy (FESEM) observations demonstrated decreased biofilm adhesion and destruction of biofilm architecture after treatment with CA. These findings indicated that CA acts as a natural bacteriostatic agent to control Sh. flexneri in food processing and production.}, } @article {pmid36037949, year = {2022}, author = {Zou, L and Zhou, M and Qin, C and Luo, Z and Zhang, H and Yang, Z and Cheng, H and Li, R and He, Q and Ai, H}, title = {Improving the performance of coupled solid carbon source biofilm carriers through pore-forming methods.}, journal = {Chemosphere}, volume = {308}, number = {Pt 1}, pages = {136172}, doi = {10.1016/j.chemosphere.2022.136172}, pmid = {36037949}, issn = {1879-1298}, mesh = {Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; Carbon/metabolism ; *Denitrification ; Nitrification ; Nitrogen/metabolism ; Waste Disposal, Fluid/methods ; *Wastewater ; }, abstract = {Coupled solid carbon source biofilm carriers (CCBs) was usually utilized to enhance the treatment efficiency of low carbon/nitrogen (C/N) wastewater. However, current CCBs have low carbon release capacity because of its small inner mass transfer coefficient. Therefore, this study innovatively applied pore-forming methods to modify CCBs. After orthogonal selections, two porous CCBs, which were respectively prepared through circulating freezing pore-forming method (CCB2) and ammonium bicarbonate pore-forming method (CCB3), were proposed and further applied in sequencing batch moving bed biofilm reactors (SBMBBRs). The results indicated that circulating freezing pore-forming method could improve the mechanical strength and carbon source release rate of CCBs. In addition, CCB2 could significantly enhance the total nitrogen (TN) removal efficiency of SBMBBRs, when compared with the non-porous CCBs (i.e., CCB1). Further biofilm and simultaneous nitrification and denitrification (SND) rate calculation attributed this enhancement to the higher biofilm amount (i.e., 0.06 g g[-1] CCB) and the higher SND rate (i.e., 33.60%). Microbial community analysis reiterated these observations that CCB2 and CCB3 could accumulate Proteobacteria, Actinobacteriota and Nitrospirota, and also stimulate nitrification and denitrification associated pathways. More importantly, the cost calculation indicated CCB2 cost only 47.37% of CCB1 and 31.34% of CCB3, showing highly economic applicability. Overall, our results collectively proved that CCBs manufactured by circulating freezing pore-forming method could provide more carbon releasing points and microorganisms attaching positions, exhibiting effectively nitrogen removal when treating low C/N wastewater.}, } @article {pmid36037838, year = {2022}, author = {Liu, H and Li, L and Ye, W and Ru, L and Liu, G and Peng, X and Wang, X}, title = {Nitrogen removal from low COD/N interflow using a hybrid activated sludge membrane-aerated biofilm reactor (H-MABR).}, journal = {Bioresource technology}, volume = {362}, number = {}, pages = {127855}, doi = {10.1016/j.biortech.2022.127855}, pmid = {36037838}, issn = {1873-2976}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Denitrification ; Nitrification ; *Nitrogen/metabolism ; *Sewage ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {A hybrid activated sludge membrane-aerated biofilm reactor based on a two-stage simultaneous nitrification-denitrification (SND) process was built, and its utility for treating interflow with low chemical oxygen demand (COD)/total nitrogen (TN) (COD/N) was explored. The operating performance, functional microbial communities, and functional genes for nitrogen metabolism were evaluated at low COD/N (4-1.3). The reactor could achieve stable operation at COD/N = 4-1.5, and the removal efficiency of COD, TN, and ammonia nitrogen was stable at 90.30 ± 2.36 %, 85.69 ± 2.22 %, and 89.52 ± 6.06 %, respectively. The SND rates were 70.89 % and 50.75 % when influent COD/N was 2.0 and 1.7, respectively, indicating that SND makes an important contribution to nitrogen removal under these two COD/N conditions. Microbial analysis revealed that the sampling sites with a high abundance of denitrification genes in the outer ring experienced aerobic conditions, inferring that aerobic denitrification also plays an important role in denitrification.}, } @article {pmid36037789, year = {2022}, author = {Gómez, AC and Lyons, T and Mamat, U and Yero, D and Bravo, M and Daura, X and Elshafee, O and Brunke, S and Gahan, CGM and O'Driscoll, M and Gibert, I and O'Sullivan, TP}, title = {Synthesis and evaluation of novel furanones as biofilm inhibitors in opportunistic human pathogens.}, journal = {European journal of medicinal chemistry}, volume = {242}, number = {}, pages = {114678}, doi = {10.1016/j.ejmech.2022.114678}, pmid = {36037789}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Candida albicans ; *Escherichia coli ; Humans ; Pseudomonas aeruginosa ; *Staphylococcus aureus ; }, abstract = {Diseases caused by biofilm-forming pathogens are becoming increasingly prevalent and represent a major threat to human health. This trend has prompted a search for novel inhibitors of microbial biofilms which could, for example, be used to potentiate existing antibiotics. Naturally-occurring, halogenated furanones isolated from marine algae have proven to be effective biofilm inhibitors in several bacterial species. In this work, we report the synthesis of a library of novel furanones and their subsequent evaluation as biofilm inhibitors in several opportunistic human pathogens including S. enterica, S. aureus, E. coli, S. maltophilia, P. aeruginosa and C. albicans. A number of the most potent compounds were subjected to further analysis by confocal laser-scanning microscopy for their effects on P. aeruginosa and C. albicans biofilms individually, in addition to mixed polymicrobial biofilms. Lastly, we investigated the impact of a promising candidate on survival rates in vivo using a Galleria mellonella model.}, } @article {pmid36034896, year = {2022}, author = {Raz, C and Paramonov, MM and Shemesh, M and Argov-Argaman, N}, title = {The milk fat globule size governs a physiological switch for biofilm formation by Bacillus subtilis.}, journal = {Frontiers in nutrition}, volume = {9}, number = {}, pages = {844587}, pmid = {36034896}, issn = {2296-861X}, abstract = {Milk lipids are organized in the form of milk fat globules (MFG), ranging in size from 0. 1 to 15 μm. The MFG size is closely associated with the composition of fatty acids, polar lipids, sphingolipids, cholesterol and the content of the MFG membrane (MFGM). Also, the MFGM integral proteins and glycoconjugates differ in composition and structure between different MFG size groups. These compositional differences may modulate the functionality of the MFG and its interaction with microbial cells. We report that small (2.3 μm) MFG facilitates the growth of the Gram-positive bacterium Bacillus subtilis whereas induction of biofilm formation was found in the presence of large (7.0 μm) MFG. Attempting to distinguish between the role played by the size from that played by the composition of the MFG, we compared phospholipid composition between treatments. We found that adjusting the phosphatidylethanolamine (PE) level to the concentration found in the small MFG, increased growth but suppressed biofilm formation in the presence of large MFG. The same normalization protocol for phosphatidylinositol (PI) or sphingomyeline (SM) did not exert a similar effect, suggesting a specific role for PE in regulating bacteria proliferation. We suggest that the content of MFGM, affected by MFG size, governs the ability of B. subtilis to utilize lipids from milk fat. This process might affect the bacterial decision-making toward biofilm formation or growth.}, } @article {pmid36033896, year = {2022}, author = {Chi, Y and Wang, Y and Ji, M and Li, Y and Zhu, H and Yan, Y and Fu, D and Zou, L and Ren, B}, title = {Natural products from traditional medicine as promising agents targeting at different stages of oral biofilm development.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {955459}, pmid = {36033896}, issn = {1664-302X}, abstract = {Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents against infectious diseases; however, the emergence of drug resistance and the disruption of oral microecology have challenged their applications. The discovery of new antibiotic-independent agents is a promising strategy against biofilm-induced infections. Natural products from traditional medicine have shown potential antibiofilm activities in the oral cavity with high safety, cost-effectiveness, and minimal adverse drug reactions. Aiming to highlight the importance and functions of natural products from traditional medicine against oral biofilms, here we summarized and discussed the antibiofilm effects of natural products targeting at different stages of the biofilm formation process, including adhesion, proliferation, maturation, and dispersion, and their effects on multi-species biofilms. The perspective of antibiofilm agents for oral infectious diseases to restore the balance of oral microecology is also discussed.}, } @article {pmid36033861, year = {2022}, author = {Wang, N and Gao, J and Xiao, S and Zhuang, G}, title = {Overexpression of pdeR promotes biofilm formation of Paracoccus denitrificans by promoting ATP production and iron acquisition.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {966976}, pmid = {36033861}, issn = {1664-302X}, abstract = {Bacterial biofilms are ubiquitous in natural environments and play an essential role in bacteria's environmental adaptability. Quorum sensing (QS), as the main signaling mechanism bacteria used for cell-to-cell communication, plays a key role in bacterial biofilm formation. However, little is known about the role of QS circuit in the N-transformation type strain, Paracoccus denitrificans, especially for the regulatory protein PdeR. In this study, we found the overexpression of pdeR promoted bacterial aggregation and biofilm formation. Through RNA-seq analysis, we demonstrated that PdeR is a global regulator which could regulate 656 genes expression, involved in multiple metabolic pathways. Combined with transcriptome as well as biochemical experiments, we found the overexpressed pdeR mainly promoted the intracellular degradation of amino acids and fatty acids, as well as siderophore biosynthesis and transportation, thus providing cells enough energy and iron for biofilm development. These results revealed the underlying mechanism for PdeR in biofilm formation of P. denitrificans, adding to our understanding of QS regulation in biofilm development.}, } @article {pmid36032292, year = {2022}, author = {Wang, Z and Guo, L and Li, J and Li, J and Cui, L and Dong, J and Meng, X and Qian, C and Wang, H}, title = {Antibiotic resistance, biofilm formation, and virulence factors of isolates of staphylococcus pseudintermedius from healthy dogs and dogs with keratitis.}, journal = {Frontiers in veterinary science}, volume = {9}, number = {}, pages = {903633}, pmid = {36032292}, issn = {2297-1769}, abstract = {Canine bacterial keratitis is a common infection that can potentially threaten vision. Staphylococcus pseudintermedius (S. pseudintermedius) is an opportunistic pathogen that has been isolated from the canine conjunctival sac but there are only a few reports on the role of this bacterium in canine keratitis. This study focused on the distribution rate of S. pseudintermedius in the canine conjunctival sac, and the antibiotic resistance, biofilm-producing ability, and dissemination of virulence factors in strains of S. pseudintermedius isolated from healthy dogs and dogs with keratitis. The study included 35 healthy dogs and 40 dogs with keratitis. Bacterial species were confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Strains of S. pseudintermedius were screened for resistance against nine different antibiotics by the Kirby-Bauer assay. The ability to produce biofilm was investigated by microtiter plate assay (MtP) and amplification of icaA and icaD genes. Virulence factors in the strains were also evaluated. A total of 132 aerobic bacteria were isolated from the 119 samples in the study. Among them, 67 bacterial strains were isolated from 70 eyes of healthy dogs, and 65 bacterial strains were isolated from 49 eyes of dogs with keratitis. The prevalence of S. pseudintermedius, which was the most frequent bacterial isolate in both the groups, was 20.9% in the healthy group and 23.08% in the keratitis group. Most of the isolates of S. pseudintermedius were sensitive to rifampin (96.6%), oxacillin (100%), and neomycin (96.6%), and resistant to tetracycline (96.6%). Virulence factors such as lip (96.6%), hlgB (96.6%), and hlgA (96.6%) were found in most of the isolates, and 89.66% of isolates were classed as biofilm producers. In conclusion, S. pseudintermedius was the common bacterium in the conjunctivital sac of the healthy dogs and dogs with keratitis in Yangzhou, China, and the presence of virulence factors and biofilm-formation ability were high in the strains isolated from the dogs with keratitis.}, } @article {pmid36031955, year = {2022}, author = {Charles, CJ and Rout, SP and Jackson, BR and Boxall, SA and Akbar, S and Humphreys, PN}, title = {The evolution of alkaliphilic biofilm communities in response to extreme alkaline pH values.}, journal = {MicrobiologyOpen}, volume = {11}, number = {4}, pages = {e1309}, pmid = {36031955}, issn = {2045-8827}, mesh = {*Biofilms ; Biomass ; *Extracellular Polymeric Substance Matrix ; Hydrogen-Ion Concentration ; Microbial Consortia ; }, abstract = {Extremes of pH present a challenge to microbial life and our understanding of survival strategies for microbial consortia, particularly at high pH, remains limited. The utilization of extracellular polymeric substances within complex biofilms allows micro-organisms to obtain a greater level of control over their immediate environment. This manipulation of the immediate environment may confer a survival advantage in adverse conditions to biofilms. Within the present study alkaliphilic biofilms were created at pH 11.0, 12.0, or 13.0 from an existing alkaliphilic community. In each pH system, the biofilm matrix provided pH buffering, with the internal pH being 1.0-1.5 pH units lower than the aqueous environment. Increasing pH resulted in a reduced removal of substrate and standing biomass associated with the biofilm. At the highest pH investigated (pH 13.0), the biofilms matrix contained a greater degree of eDNA and the microbial community was dominated by Dietzia sp. and Anaerobranca sp.}, } @article {pmid36031954, year = {2022}, author = {Chun, ALM and Mosayyebi, A and Butt, A and Carugo, D and Salta, M}, title = {Early biofilm and streamer formation is mediated by wall shear stress and surface wettability: A multifactorial microfluidic study.}, journal = {MicrobiologyOpen}, volume = {11}, number = {4}, pages = {e1310}, pmid = {36031954}, issn = {2045-8827}, mesh = {Biofilms ; *Microfluidics ; Plastics ; *Polyethylene ; Pseudomonas aeruginosa ; Wettability ; }, abstract = {Biofilms are intricate communities of microorganisms encapsulated within a self-produced matrix of extra-polymeric substances (EPS), creating complex three-dimensional structures allowing for liquid and nutrient transport through them. These aggregations offer constituent microorganisms enhanced protection from environmental stimuli-like fluid flow-and are also associated with higher resistance to antimicrobial compounds, providing a persistent cause of concern in numerous sectors like the marine (biofouling and aquaculture), medical (infections and antimicrobial resistance), dentistry (plaque on teeth), food safety, as well as causing energy loss and corrosion. Recent studies have demonstrated that biofilms interact with microplastics, often influencing their pathway to higher trophic levels. Previous research has shown that initial bacterial attachment is affected by surface properties. Using a microfluidic flow cell, we have investigated the relationship between both wall shear stress (τw) and surface properties (surface wettability) upon biofilm formation of two species (Cobetia marina and Pseudomonas aeruginosa). We investigated biofilm development on low-density polyethylene (LDPE) membranes, Permanox® slides, and glass slides, using nucleic acid staining and end-point confocal laser scanning microscopy. The results show that flow conditions affect biomass, maximum thickness, and surface area of biofilms, with higher τw (5.6 Pa) resulting in thinner biofilms than lower τw (0.2 Pa). In addition, we observed differences in biofilm development across the surfaces tested, with LDPE typically demonstrating more overall biofilm in comparison to Permanox® and glass. Moreover, we demonstrate the formation of biofilm streamers under laminar flow conditions within straight micro-channels.}, } @article {pmid36031132, year = {2022}, author = {Shao, S and Zhong, J and Wang, C and Pan, D and Wu, X}, title = {Performance of simultaneous nitrification-denitrification and denitrifying phosphorus and manganese removal by driving a single-stage moving bed biofilm reactor based on manganese redox cycling.}, journal = {Bioresource technology}, volume = {362}, number = {}, pages = {127846}, doi = {10.1016/j.biortech.2022.127846}, pmid = {36031132}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Manganese ; Manganese Compounds ; *Nitrification ; Nitrogen ; Oxidation-Reduction ; Oxides ; *Phosphorus ; Sewage ; Sodium ; Succinates ; Waste Disposal, Fluid ; Wastewater/chemistry ; }, abstract = {Simultaneous removal of NH4[+]-N, NO3[-]-N, COD, and P by manganese redox cycling in nutrient wastewater was established with a single-stage moving bed biofilm reactor (MBBR) under low C/N ratio. When sodium succinate replaced the conventional denitrifying carbon source, removal efficiencies of TN, NO3[-]-N, NH4[+]-N, TP, and Mn[2+] were 65.13 %, 79.63 %, 92.79 %, 51.57 %, and 68.10 %, respectively. Based on modified Stover-Kincannon model, 11.03 and 10.05 mg TN·L[-1]·h[-1] of Umax values were obtained with sodium acetate and sodium succinate as substrates. Extracellular polymeric substances were used to evaluate the characteristics of biofilm, and microbial community of biofilm was identified. Transformation processes of NO3[-]-N, NH4[+]-N, Mn[2+], and P were investigated, suggesting that the main functional groups (e.g., CO, Mn-O, and CN bonds) participated in N, P, and Mn[2+] removal, and MnO2 was the main component of biogenic manganese oxides. This study provides a new strategy for nutrients removal by Mn[2+] driven MBBR.}, } @article {pmid36030941, year = {2022}, author = {Li, K and Yu, J and Chen, X and Kong, D and Peng, Y and Xiu, X and Su, H and Yan, L}, title = {Effects of tire wear particles with and without photoaging on anaerobic biofilm sulfide production in sewers and related mechanisms.}, journal = {Chemosphere}, volume = {308}, number = {Pt 1}, pages = {136185}, doi = {10.1016/j.chemosphere.2022.136185}, pmid = {36030941}, issn = {1879-1298}, mesh = {Anaerobiosis ; Biofilms ; *Environmental Pollutants ; *Metals, Heavy ; Microplastics ; Plastics ; *Polycyclic Aromatic Hydrocarbons ; Reactive Oxygen Species ; Sewage ; *Skin Aging ; Sulfates ; Sulfides ; Wastewater ; Zinc ; }, abstract = {Tire wear particles (TWPs) are considered to be one of the major sources of microplastics (MPs) in sewers; however, little has been reported on the surface properties and photochemical behavior of TWPs, especially in terms of their environmental persistent radicals, leachate type, and response after photoaging. It is also unknown how TWPs influence the production of common pollutants (e.g., sulfides) in anaerobic biofilms in sewers. In our study, the effects of cryogenically milled tire treads (C-TWPs) and their corresponding photoaging products (photoaging-TWPs, A-TWPs) on anaerobic biofilm sulfide production in sewers and related mechanisms were studied. The results showed that the two TWPs at a low concentration (0.1 mg L[-1]) exerted no significant (p > 0.05) effects on sulfide yield, whereas exposure to a high concentration of TWPs (100 mg L[-1]) inversely affected sulfide yield, with A-TWPs exerting a significant inhibitory effect on sulfide yield in the sewers (p < 0.01). The main reason was that A-TWPs carried higher concentrations of reactive environmental persistent radicals on their surfaces after photoaging than C-TWPs, which could induce the formation of oxygen radicals. In addition, A-TWPs were more uniformly distributed in the wastewater system and could penetrate the biofilm to damage bacterial cells, and their ability to leach polycyclic aromatic hydrocarbons and heavy metals such as zinc additives enhanced their toxic effects. In contrast, C-TWPs contributed significantly to sulfide production (p < 0.01), primarily because of their low biotoxicity, ability to leach a considerable amount of sulfide, and stimulatory effect on anaerobic biofilm surface sulfate-reducing bacteria. Our study complements the toxicity studies of the TWPs particles themselves and provides insight on a new influencing factor for determining the changes in sulfide generation and control measures in sewers.}, } @article {pmid36029807, year = {2022}, author = {Aristotelous, AC}, title = {Biofilm neutrophils interactions under hypoxia: A mathematical modeling study.}, journal = {Mathematical biosciences}, volume = {352}, number = {}, pages = {108893}, doi = {10.1016/j.mbs.2022.108893}, pmid = {36029807}, issn = {1879-3134}, mesh = {Bacteria/metabolism ; *Biofilms ; Humans ; Hypoxia/metabolism ; Models, Theoretical ; *Neutrophils ; Oxygen/metabolism ; Virulence Factors/metabolism ; }, abstract = {Neutrophils are important to the defense of the host against bacterial infection. Pathogens and the immune system cells create via respiration, a hypoxic environment in infected regions. Hypoxic conditions affect both the neutrophil's ability to eradicate the infection and also change the behavior of the bacterial-pathogens by eliciting the production of various virulence factors, the creation of bacterial biofilm and the initialization of anaerobic metabolism. In this work interactions of bacterial biofilm and neutrophils are studied in a domain where oxygen is diffusing into the environment and is being consumed by biofilm. Within a hypoxic environment, bacteria grow anaerobically and secrete higher levels of toxin that diffuses and lyses neutrophils. A mathematical model explicitly representing the biofilm volume fraction, oxygen, and diffusive virulence factors (toxin) as well as killing of bacteria by neutrophils is developed and studied first in 1D and then in 2D. Stability analysis and numerical simulations showing the effects of oxygen and toxin concentration on neutrophil-bacteria interactions are presented to identify different possible scenarios that can lead to elimination of the infection or its persistence as a chronic infection. Specifically, when bacteria are allowed to utilize anaerobic breathing and or to produce toxin, their fitness is enhanced against neutrophils attacks. A possible insight on how virulent bacterial colonies can synergistically resist neutrophils and survive is presented.}, } @article {pmid36029504, year = {2022}, author = {Mahmood, KI and Najmuldeen, HHR and Rachid, SK}, title = {Physiological regulation for enhancing biosynthesis of biofilm-inhibiting secondary metabolites in Streptomyces cellulosae.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {68}, number = {5}, pages = {33-46}, doi = {10.14715/cmb/2022.68.5.5}, pmid = {36029504}, issn = {1165-158X}, mesh = {Anti-Bacterial Agents ; Biofilms ; DNA, Ribosomal ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; *Streptomyces ; }, abstract = {Although the production of the secondary metabolite is frequently restricted, methods to regulate and optimize their synthesis are extremely beneficial. The current study proposes to enhance the production of antibiofilm metabolite in Streptomyces cellulosae (S. cellulosae). It was isolated from soil by growing on Gause's media and identified by colony morphology and genomic sequencing of 16S rDNA. Antibacterial and antibiofilm activities of the isolates were screened against a series of pathogenic bacteria by agar plug diffusion and 96 well microtiter plate methods, respectively. Physiological regulation of the bacterial bioactivity against biofilm formation was monitored under different cultural conditions. The isolated Streptomyces sequence analysis of the 16S rDNA was 100% identical to the sequence of S. cellulosae strain NBRC 13027. Physical (temperature and pH) and chemical (carbon, nitrogen, and minerals) culture medium factors have shown variable impacts on the growth and bioactive substances of S. cellulosae. Moreover, results of simple linear regression and correlation suggested that most of the physiological regulations with the highest response (r2= 0.85-0.99; p<0.01) and linearly (r= 0.88-0.99; p<0.01) were correlated between microbial biomass and crude extract. Lastly, under different culture growth conditions, biofilm inhibition was tested against Pseudomonas aeruginosa (P. aeruginosa). The physiological regulation results exhibited that 1 μg/mL of the extract was the most efficient concentration against biofilm formation in P. aeruginosa while 3 μg/mL is an effective bactericidal dose against P. aeruginosa. We concluded that S. cellulosae can produce antibacterial and antibiofilm metabolites. Physiological regulation is considered a powerful tool that can be used for increasing the biosynthesis of the active metabolites and biomass.}, } @article {pmid36028078, year = {2022}, author = {Lemonnier, C and Chalopin, M and Huvet, A and Le Roux, F and Labreuche, Y and Petton, B and Maignien, L and Paul-Pont, I and Reveillaud, J}, title = {Time-series incubations in a coastal environment illuminates the importance of early colonizers and the complexity of bacterial biofilm dynamics on marine plastics.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {312}, number = {}, pages = {119994}, doi = {10.1016/j.envpol.2022.119994}, pmid = {36028078}, issn = {1873-6424}, mesh = {Bacteria/genetics ; Biofilms ; Humans ; *Microplastics ; *Plastics ; Polymers ; Water ; }, abstract = {The problematic of microplastics pollution in the marine environment is tightly linked to their colonization by a wide diversity of microorganisms, the so-called plastisphere. The composition of the plastisphere relies on a complex combination of multiple factors including the surrounding environment, the time of incubation along with the polymer type, making it difficult to understand how the biofilm evolves during the microplastic lifetime over the oceans. To better define bacterial community assembly processes on plastics, we performed a 5 months spatio-temporal survey of the plastisphere in an oyster farming area in the Bay of Brest (France). We deployed three types of plastic pellets in two positions in the foreshore and in the water column. Plastic-associated biofilm composition in all these conditions was monitored using 16 S rRNA metabarcoding and compared to free-living and attached bacterial members of seawater. We observed that bacterial families associated to plastic pellets were significantly distinct from the ones found in seawater, with a significant prevalence of filamentous Cyanobacteria on plastics. No convergence towards a unique plastisphere was detected between polymers exposed in the intertidal and subtidal area, emphasizing the central role of the surrounding environment on constantly shaping the plastisphere community diversity. However, we could define a bulk of early-colonizers of marine biofilms such as Alteromonas, Pseudoalteromonas or Vibrio. These early-colonizers could reach high abundances in floating microplastics collected in field-sampling studies, suggesting the plastic-associated biofilms could remain at early development stages across large oceanic scales. Our study raises the hypothesis that most members of the plastisphere, including putative pathogens, could result of opportunistic colonization processes and unlikely long-term transport.}, } @article {pmid36028022, year = {2022}, author = {Zhou, Q and Tu, C and Liu, Y and Li, Y and Zhang, H and Vogts, A and Plewe, S and Pan, X and Luo, Y and Waniek, JJ}, title = {Biofilm enhances the copper (II) adsorption on microplastic surfaces in coastal seawater: Simultaneous evidence from visualization and quantification.}, journal = {The Science of the total environment}, volume = {853}, number = {}, pages = {158217}, doi = {10.1016/j.scitotenv.2022.158217}, pmid = {36028022}, issn = {1879-1026}, mesh = {Microplastics ; Plastics ; Copper/analysis ; Adsorption ; Chlorine/analysis ; *Water Pollutants, Chemical/analysis ; Seawater ; Biofilms ; Metals ; *Environmental Pollutants/analysis ; }, abstract = {Microplastics (MPs) exposed to the urban coastal seawater could form biofilms, which facilitate the adsorption and transportation of hazardous contaminants. However, influence of biofilms on the metal adsorption of MPs, especially the co-existence of biofilm and metals on MPs, is still less known. In this study, the adsorption of copper (Cu) on biofilm-coated MPs (BMPs) was visually analyzed and quantified. The results of scanning electron microscopy in combination with energy dispersive X-ray showed that biofilm and metals co-occurred on MPs in seawater. The nanoscale secondary ion mass spectrometry images further exhibited that the distribution of Cu, chlorine (Cl) and biofilm on MP surfaces was highly consistent. Moreover, the adsorption of Cu(II) on BMPs was enhanced as quantified by inductively coupled plasma-mass spectrometer. Furthermore, different species on BMPs with and without Cu were identified, and their potential functions of metal or Cl metabolism were predicted based on KEGG pathway database. Overall, for the first time, this study provides visual and quantified evidences for the enhancement of Cu(II) adsorption on BMPs based on co-localization, and it may shed a light on the development of methodologies for investigating the interaction among MPs, biofilms and pollutants in marine environment.}, } @article {pmid36027959, year = {2022}, author = {Fu, H and Wang, J and Liu, Q and Ding, L and Ren, H}, title = {The role of immobilized quorum sensing strain in promoting biofilm formation of Moving Bed Biofilm Reactor during long-term stable operation.}, journal = {Environmental research}, volume = {215}, number = {Pt 1}, pages = {114159}, doi = {10.1016/j.envres.2022.114159}, pmid = {36027959}, issn = {1096-0953}, mesh = {*Acyl-Butyrolactones ; Biofilms ; Bioreactors/microbiology ; Extracellular Polymeric Substance Matrix ; *Quorum Sensing ; Wastewater ; }, abstract = {Quorum sensing (QS) signaling plays a significant role in the natural regulation of biofilm formation. Multiple species QS systems in wastewater treatment processes have received significant attention in recent years and this study presents a long-term analysis of QS signaling, bacterial structures and extracellular polymeric substance (EPS) during biofilm formation, detachment and reformation processes. Six types of Acyl homoserine lactones (AHLs) were found to be closely related to different phases of biofilm development, with both QS and quorum quenching (QQ) strains being identified as drivers of various biofilm phases and 10 strains presenting a close relationship with AHLs (p < 0.05). Meanwhile, QS strain Sphingomonas rubra was immobilized and added into reactor systems, resulting in significant increase in AHL content, EPS production, and adhesion strength of biofilm (p < 0.05), which might promote biofilm formation processes during long-term stable operation. This study provides a potentially simple and economical way to improve activity and stability of MBBR in complex wastewater systems.}, } @article {pmid36018573, year = {2022}, author = {Kluzek, M and Oppenheimer-Shaanan, Y and Dadosh, T and Morandi, MI and Avinoam, O and Raanan, C and Goldsmith, M and Goldberg, R and Klein, J}, title = {Designer Liposomic Nanocarriers Are Effective Biofilm Eradicators.}, journal = {ACS nano}, volume = {16}, number = {10}, pages = {15792-15804}, pmid = {36018573}, issn = {1936-086X}, mesh = {*Liposomes/pharmacology ; Phosphorylcholine ; Lipopolysaccharides/pharmacology ; Biofilms ; Pseudomonas aeruginosa ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Ions ; Microbial Sensitivity Tests ; }, abstract = {Drug delivery via nanovehicles is successfully employed in several clinical settings, yet bacterial infections, forming microbial communities in the form of biofilms, present a strong challenge to therapeutic treatment due to resistance to conventional antimicrobial therapies. Liposomes can provide a versatile drug-vector strategy for biofilm treatment, but are limited by the need to balance colloidal stability with biofilm penetration. We have discovered a liposomic functionalization strategy, using membrane-embedded moieties of poly[2-(methacryloyloxy)ethyl phosphorylcholine], pMPC, that overcomes this limitation. Such pMPCylation results in liposomic stability equivalent to current functionalization strategies (mostly PEGylation, the present gold-standard), but with strikingly improved cellular uptake and cargo conveyance. Fluorimetry, cryo-electron, and fluorescence microscopies reveal a far-enhanced antibiotic delivery to model Pseudomonas aeruginosa biofilms by pMPC-liposomes, followed by faster cytosolic cargo release, resulting in significantly greater biofilm eradication than either PEGylation or free drug. Moreover, this combination of techniques uncovers the molecular mechanism underlying the enhanced interaction with bacteria, indicating it arises from bridging by divalent ions of the zwitterionic groups on the pMPC moieties to the negatively charged lipopolysaccharide chains emanating from the bacterial membranes. Our results point to pMPCylation as a transformative strategy for liposomal functionalization, leading to next-generation delivery systems for biofilm treatment.}, } @article {pmid36018039, year = {2022}, author = {Lin, JS and Bekale, LA and Molchanova, N and Nielsen, JE and Wright, M and Bacacao, B and Diamond, G and Jenssen, H and Santa Maria, PL and Barron, AE}, title = {Anti-persister and Anti-biofilm Activity of Self-Assembled Antimicrobial Peptoid Ellipsoidal Micelles.}, journal = {ACS infectious diseases}, volume = {8}, number = {9}, pages = {1823-1830}, pmid = {36018039}, issn = {2373-8227}, support = {DP1 AG072438/AG/NIA NIH HHS/United States ; P30 GM124169/GM/NIGMS NIH HHS/United States ; R41 DC020077/DC/NIDCD NIH HHS/United States ; S10 OD018483/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Humans ; Micelles ; Microbial Sensitivity Tests ; *Peptoids/pharmacology ; Recurrence ; }, abstract = {Although persister cells are the root cause of resistance development and relapse of chronic infections, more attention has been focused on developing antimicrobial agents against resistant bacterial strains than on developing anti-persister agents. Frustratingly, the global preclinical antibacterial pipeline does not include any anti-persister drug. Therefore, the central point of this work is to explore antimicrobial peptidomimetics called peptoids (sequence-specific oligo-N-substituted glycines) as a new class of anti-persister drugs. In this study, we demonstrate that one particular antimicrobial peptoid, the sequence-specific pentamer TM5, is active against planktonic persister cells and sterilizes biofilms formed by both Gram-negative and Gram-positive bacteria. Moreover, we demonstrate the potential of TM5 to inhibit cytokine production induced by lipopolysaccharides from Gram-negative bacteria. We anticipate that this work can pave the way to the development of new anti-persister agents based on antimicrobial peptoids of this class to simultaneously help address the crisis of bacterial resistance and reduce the occurrence of the relapse of chronic infections.}, } @article {pmid36017072, year = {2023}, author = {Sun, T and Huang, J and Zhang, W and Zheng, X and Wang, H and Liu, J and Leng, H and Yuan, W and Song, C}, title = {Simvastatin-hydroxyapatite coatings prevent biofilm formation and improve bone formation in implant-associated infections.}, journal = {Bioactive materials}, volume = {21}, number = {}, pages = {44-56}, pmid = {36017072}, issn = {2452-199X}, abstract = {Implant-associated infections (IAIs) caused by biofilm formation are the most devastating complications of orthopedic surgery. Statins have been commonly and safely used drugs for hypercholesterolemia for many years. Here, we report that simvastatin-hydroxyapatite-coated titanium alloy prevents biofilm-associated infections. The antibacterial properties of simvastatin against Staphylococcus aureus and Staphylococcus epidermidis biofilms in vitro was confirmed by crystal violet staining and live-dead bacterial staining. We developed a simvastatin-and hydroxyapatite (Sim-HA)-coated titanium alloy via electrochemical deposition. Sim-HA coatings inhibited Staphylococcus aureus biofilm formation and improved the biocompatibility of the titanium alloy. Sim-HA coatings effectively prevented Staphylococcus aureus IAI in rat femurs, as confirmed by radiological assessment and histological examination. The antibacterial effects of the Sim-HA coatings were attributed to their inhibitory effects on biofilm formation, as verified by scanning electron microscopic observations and bacterial spread plate analysis. In addition, the Sim-HA coatings enhanced osteogenesis and osteointegration, as verified by micro-CT, histological evaluation, and biomechanical pull-out tests. In summary, Sim-HA coatings are promising implant materials for protection against biofilm-associated infections.}, } @article {pmid36016795, year = {2022}, author = {Liu, PX and Zhang, XY and Wang, Q and Li, YY and Sun, WD and Qi, Y and Zhou, K and Han, XG and Chen, ZG and Fang, WH and Jiang, W}, title = {Biological and transcriptional studies reveal VmeL is involved in motility, biofilm formation and virulence in Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {976334}, pmid = {36016795}, issn = {1664-302X}, abstract = {Vibrio parahaemolyticus is a marine pathogen thought to be the leading cause of seafood-borne gastroenteritis globally, urgently requiring efficient management methods. V. parahaemolyticus encodes 12 resistance/nodulation/division (RND) efflux systems. However, research on these systems is still in its infancy. In this study, we discovered that the inactivation of VmeL, a membrane fusion protein within the RND efflux systems, led to reduction of the ability of biofilm formation. Further results displayed that the decreased capacity of Congo red binding and the colony of ΔvmeL is more translucent compared with wild type strains, suggested reduced biofilm formation due to decreased production of biofilm exopolysaccharide upon vmeL deletion. In addition, the deletion of vmeL abolished surface swarming and swimming motility of V. parahaemolyticus. Additionally, deletion of vmeL weakened the cytotoxicity of V. parahaemolyticus towards HeLa cells, and impaired its virulence in a murine intraperitoneal infection assay. Finally, through RNA-sequencing, we ascertained that there were 716 upregulated genes and 247 downregulated genes in ΔvmeL strain. KEGG enrichment analysis revealed that quorum sensing, bacterial secretion systems, ATP-binding cassette transporters, and various amino acid metabolism pathways were altered due to the inactivation of vmeL. qRT-PCR further confirmed that genes accountable to the type III secretion system (T3SS1) and lateral flagella were negatively affected by vmeL deletion. Taken together, our results suggest that VmeL plays an important role in pathogenicity, making it a good target for managing infection with V. parahaemolyticus.}, } @article {pmid36016778, year = {2022}, author = {Ghosh, S and Lahiri, D and Nag, M and Sarkar, T and Pati, S and Edinur, HA and Kumar, M and Mohd Zain, MRA and Ray, RR}, title = {Precision targeting of food biofilm-forming genes by microbial scissors: CRISPR-Cas as an effective modulator.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {964848}, pmid = {36016778}, issn = {1664-302X}, abstract = {The abrupt emergence of antimicrobial resistant (AMR) bacterial strains has been recognized as one of the biggest public health threats affecting the human race and food processing industries. One of the causes for the emergence of AMR is the ability of the microorganisms to form biofilm as a defense strategy that restricts the penetration of antimicrobial agents into bacterial cells. About 80% of human diseases are caused by biofilm-associated sessile microbes. Bacterial biofilm formation involves a cascade of genes that are regulated via the mechanism of quorum sensing (QS) and signaling pathways that control the production of the extracellular polymeric matrix (EPS), responsible for the three-dimensional architecture of the biofilm. Another defense strategy utilized commonly by various bacteria includes clustered regularly interspaced short palindromic repeats interference (CRISPRi) system that prevents the bacterial cell from viral invasion. Since multigenic signaling pathways and controlling systems are involved in each and every step of biofilm formation, the CRISPRi system can be adopted as an effective strategy to target the genomic system involved in biofilm formation. Overall, this technology enables site-specific integration of genes into the host enabling the development of paratransgenic control strategies to interfere with pathogenic bacterial strains. CRISPR-RNA-guided Cas9 endonuclease, being a promising genome editing tool, can be effectively programmed to re-sensitize the bacteria by targeting AMR-encoding plasmid genes involved in biofilm formation and virulence to revert bacterial resistance to antibiotics. CRISPRi-facilitated silencing of genes encoding regulatory proteins associated with biofilm production is considered by researchers as a dependable approach for editing gene networks in various biofilm-forming bacteria either by inactivating biofilm-forming genes or by integrating genes corresponding to antibiotic resistance or fluorescent markers into the host genome for better analysis of its functions both in vitro and in vivo or by editing genes to stop the secretion of toxins as harmful metabolites in food industries, thereby upgrading the human health status.}, } @article {pmid36015238, year = {2022}, author = {Lundin, PM and Fiser, BL and Blackledge, MS and Pickett, HL and Copeland, AL}, title = {Functionalized Self-Assembled Monolayers: Versatile Strategies to Combat Bacterial Biofilm Formation.}, journal = {Pharmaceutics}, volume = {14}, number = {8}, pages = {}, pmid = {36015238}, issn = {1999-4923}, support = {R15 GM134503/GM/NIGMS NIH HHS/United States ; R15GM134503//The National Institutes of Health/ ; CHE-1919685//National Science Foundation/ ; }, abstract = {Bacterial infections due to biofilms account for up to 80% of bacterial infections in humans. With the increased use of antibiotic treatments, indwelling medical devices, disinfectants, and longer hospital stays, antibiotic resistant infections are sharply increasing. Annual deaths are predicted to outpace cancer and diabetes combined by 2050. In the past two decades, both chemical and physical strategies have arisen to combat biofilm formation on surfaces. One such promising chemical strategy is the formation of a self-assembled monolayer (SAM), due to its small layer thickness, strong covalent bonds, typically facile synthesis, and versatility. With the goal of combating biofilm formation, the SAM could be used to tether an antibacterial agent such as a small-molecule antibiotic, nanoparticle, peptide, or polymer to the surface, and limit the agent's release into its environment. This review focuses on the use of SAMs to inhibit biofilm formation, both on their own and by covalent grafting of a biocidal agent, with the potential to be used in indwelling medical devices. We conclude with our perspectives on ongoing challenges and future directions for this field.}, } @article {pmid36015230, year = {2022}, author = {Gómez-Casanova, N and Torres-Cano, A and Elias-Rodriguez, AX and Lozano, T and Ortega, P and Gómez, R and Pérez-Serrano, J and Copa-Patiño, JL and Heredero-Bermejo, I}, title = {Inhibition of Candida glabrata Biofilm by Combined Effect of Dendritic Compounds and Amphotericin.}, journal = {Pharmaceutics}, volume = {14}, number = {8}, pages = {}, pmid = {36015230}, issn = {1999-4923}, support = {PID2020-112924RB-I00//Ministerio de Ciencia e Innovación/ ; IMMUNOTHERCAN-CM B2017/BMD-3733//Comunidad de Madrid/ ; B2017/BMD-3703//Comunidad de Madrid/ ; CM/JIN/2019-020//Comunidad de Madrid/ ; CM/JIN/2021-029//Comunidad de Madrid/ ; CCG20/CCS-013//University of Alcala/ ; PIUAH21/CC-041//University of Alcala/ ; EPU-INV-UAH/2021/002//University of Alcala/ ; }, abstract = {In the last decade, Candida glabrata has become an important emerging opportunistic pathogen not only because of the increase in nosocomial infections frequency but also because of its ability to form biofilms and its innate resistance to commercial antifungals. These characteristics make this pathogen a major problem in hospital settings, including problems regarding equipment, and in immunosuppressed patients, who are at high risk for candidemia. Therefore, there is an urgent need for the development of and search for new antifungal drugs. In this study, the efficacy of two dendritic wedges with 4-phenyl butyric acid (PBA) at the focal point and cationic charges on the surface ArCO2G2(SNMe3I)4 (1) and ArCO2G3(SNMe3I)8 (2) was studied against C. glabrata strain to inhibit the formation of biofilms and eliminate established biofilm. For this, MBIC (minimum biofilm inhibitory concentration), MBDC (minimum biofilm damaging concentrations), as well as MFCB (minimum fungicidal concentration in biofilm) and MBEC (minimum biofilm eradicating concentration) were determined. In addition, different combinations of dendrons and amphotericin B were tested to study possible synergistic effects. On the other hand, cytotoxicity studies were performed. C. glabrata cells and biofilm structure were visualized by confocal microscopy. ArCO2G2(SNMe3I)4 (1) and ArCO2G3(SNMe3I)8 (2) dendrons showed both an MBIC of 8 mg/L and a MBDC of 32 mg/L and 64 mg/L, respectively. These dendrons managed to eradicate the entirety of an established biofilm. In combination with the antifungal amphotericin, it was possible to prevent the generation of biofilms and eradicate established biofilms at lower concentrations than those required individually for each compound at these conditions.}, } @article {pmid36014993, year = {2022}, author = {Gdoura-Ben Amor, M and Culot, A and Techer, C and AlReshidi, M and Adnan, M and Jan, S and Baron, F and Grosset, N and Snoussi, M and Gdoura, R and Gautier, M}, title = {Isolation, Partial Characterization and Application of Bacteriophages in Eradicating Biofilm Formation by Bacillus cereus on Stainless Steel Surfaces in Food Processing Facilities.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {8}, pages = {}, pmid = {36014993}, issn = {2076-0817}, abstract = {The Bacillus cereus (B. cereus) group is a widespread foodborne pathogen with a persistent ability to form biofilm, and with inherent resistance to traditional treatment in the food industry. Bacteriophages are a promising biocontrol agent that could be applied to prevent or eliminate biofilms formation. We have described, in this study, the isolation from sewage samples and preliminary characterization of bacteriophages that are active against the B. cereus group. The effectiveness of phage treatment for reducing B. cereus attachment and biofilms on stainless steel surfaces has been also assessed using three incubation periods at different titrations of each phage. Out of 62 phages isolated, seven showed broad-spectrum lytic action against 174 B. cereus isolates. All selected phages appeared to be of the Siphoviridae family. SDS-PAGE proved that two phages have a similar profile, while the remainder are distinct. All isolated phages have the same restriction pattern, with an estimated genome size of around 37 kb. The isolated bacteriophages have been shown to be effective in preventing biofilm formation. Reductions of up to 1.5 log10 UFC/cm[2] have been achieved, compared to the untreated biofilms. Curative treatment reduced the bacterial density by 0.5 log10 UFC/cm[2]. These results support the prospect of using these phages as a potential alternative strategy for controlling biofilms in food systems.}, } @article {pmid36014964, year = {2022}, author = {Kaptchouang Tchatchouang, CD and Fri, J and Montso, PK and Amagliani, G and Schiavano, GF and Manganyi, MC and Baldelli, G and Brandi, G and Ateba, CN}, title = {Evidence of Virulent Multi-Drug Resistant and Biofilm-Forming Listeria Species Isolated from Various Sources in South Africa.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {8}, pages = {}, pmid = {36014964}, issn = {2076-0817}, support = {NWU BURSARY//North-West University/ ; }, abstract = {Listeriosis is a foodborne disease caused by Listeria monocytogenes species and is known to cause severe complications, particularly in pregnant women, young children, the elderly, and immunocompromised individuals. The aim of this study was to investigate the presence of Listeria species in food and water using both biochemical and species-specific PCR analysis. L. monocytogenes isolates were further screened for the presence of various antibiotic resistance, virulence, and biofilm-forming determinants profiles using phenotypic and genotypic assays. A total of 207 samples (composed of meat, milk, vegetables, and water) were collected and analyzed for presence of L. monocytogenes using species specific PCR analysis. Out of 267 presumptive isolates, 53 (19.85%) were confirmed as the Listeria species, and these comprised 26 L. monocytogenes, 3 L. innocua, 2 L. welshimeri, and 1 L. thailandensis. The remaining 21 Listeria species were classified as uncultured Listeria, based on 16SrRNA sequence analysis results. A large proportion (76% to 100%) of the L. monocytogenes were resistant to erythromycin (76%), clindamycin (100%), gentamicin (100%), tetracycline (100%), novobiocin (100%), oxacillin (100%), nalidixic acid (100%), and kanamycin (100%). The isolates revealed various multi-drug resistant (MDR) phenotypes, with E-DA-GM-T-NO-OX-NA-K being the most predominant MDR phenotypes observed in the L. monocytogenes isolates. The virulence genes prfA, hlyA, actA, and plcB were detected in 100%, 68%, 56%, and 20% of the isolates, respectively. In addition, L. monocytogenes isolates were capable of forming strong biofilm at 4 °C (%) after 24 to 72 h incubation periods, moderate for 8% isolates at 48 h and 20% at 72 h (p < 0.05). Moreover, at 25 °C and 37 °C, small proportions of the isolates displayed moderate (8−20%) biofilm formation after 48 and 72 h incubation periods. Biofilm formation genes flaA and luxS were detected in 72% and 56% of the isolates, respectively. These findings suggest that proper hygiene measures must be enforced along the food chain to ensure food safety.}, } @article {pmid36014799, year = {2022}, author = {Yuan, J and Yuan, W and Guo, Y and Wu, Q and Wang, F and Xuan, H}, title = {Anti-Biofilm Activities of Chinese Poplar Propolis Essential Oil against Streptococcus mutans.}, journal = {Nutrients}, volume = {14}, number = {16}, pages = {}, pmid = {36014799}, issn = {2072-6643}, support = {SDAIT-24-05//Shandong Province Modern Agricultural Technology System/ ; ZR2021MC110//Shandong Provincial Natural Science Foundation of China/ ; 319312101-15//the Open Project of Liaocheng University Animal Husbandry Discipline/ ; }, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms/drug effects ; China ; *Dental Caries/microbiology/prevention & control ; Glucosyltransferases/pharmacology ; Humans ; *Oils, Volatile/pharmacology ; Polysaccharides/pharmacology ; *Propolis/pharmacology ; *Streptococcus mutans/drug effects/physiology ; }, abstract = {Streptococcus mutans (S. mutans) is a common cariogenic bacterium that secretes glucosyltransferases (GTFs) to synthesize extracellular polysaccharides (EPSs) and plays an important role in plaque formation. Propolis essential oil (PEO) is one of the main components of propolis, and its antibacterial activity has been proven. However, little is known about the potential effects of PEO against S. mutans. We found that PEO has antibacterial effects against S. mutans by decreasing bacterial viability within the biofilm, as demonstrated by the XTT assay, live/dead staining assay, LDH activity assay, and leakage of calcium ions. Furthermore, PEO also suppresses the total of biofilm biomasses and damages the biofilm structure. The underlying mechanisms involved may be related to inhibiting bacterial adhesion and GTFs activity, resulting in decreased production of EPSs. In addition, a CCK8 assay suggests that PEO has no cytotoxicity on normal oral epithelial cells. Overall, PEO has great potential for preventing and treating oral bacterial infections caused by S. mutans.}, } @article {pmid36014059, year = {2022}, author = {Chen, Y and Kolodkin-Gal, I}, title = {Host-Biofilm Interactions.}, journal = {Microorganisms}, volume = {10}, number = {8}, pages = {}, pmid = {36014059}, issn = {2076-2607}, abstract = {In most natural, clinical and industrial settings, microorganisms preferentially exist in biofilms, structured communities that associate with biotic and abiotic surfaces [...].}, } @article {pmid36013945, year = {2022}, author = {Salinas, C and Florentín, G and Rodríguez, F and Alvarenga, N and Guillén, R}, title = {Terpenes Combinations Inhibit Biofilm Formation in Staphyloccocus aureus by Interfering with Initial Adhesion.}, journal = {Microorganisms}, volume = {10}, number = {8}, pages = {}, pmid = {36013945}, issn = {2076-2607}, support = {POSG17-59//Consejo Nacional de Ciencia y Tecnología/ ; }, abstract = {The biofilm is a conglomerate of cells surrounded by an extracellular matrix, which contributes to the persistence of infections. The difficulty in removing the biofilm drives the research for new therapeutic options. In this work, the effect of terpenes (−)-trans-Caryophyllene, (S)-cis-Verbenol, (S)-(−)-Limonene, (R)-(+)-Limonene, and Linalool was evaluated, individually and in combinations on bacterial growth, by assay with resazurin; the formation of biofilm, by assay with violet crystal; and the expression of associated genes, by real-time PCR, in two clinical isolates of Staphyloccocus aureus, ST30-t019 and ST5-t311, responsible for more than 90% of pediatric infections by this pathogen in Paraguay. All combinations of terpenes can inhibit biofilm formation in more than 50% without affecting bacterial growth. The most effective combination was (−)-trans-Caryophyllene and Linalool at a 500 μg/mL concentration for each, with an inhibition percentage of 88%. This combination decreased the expression levels of the sdrD, spa, agr, and hld genes associated with the initial cell adhesion stage and quorum sensing. At the same time, it increased the expression levels of the cap5B and cap5C genes related to the production of capsular polysaccharides. The combinations of compounds tested are promising alternatives to inhibit biofilm formation in S. aureus.}, } @article {pmid36012829, year = {2022}, author = {Pan, L and Yao, Y and Zheng, H and Yan, S and Chen, S}, title = {Inhibitory Effects and Mechanism of Action of Elsinochrome A on Candida albicans and Its Biofilm.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {8}, pages = {}, pmid = {36012829}, issn = {2309-608X}, support = {No. 32070007//National Natural Science Foundation of China/ ; }, abstract = {Biofilm-associated Candida albicans infections, the leading cause of invasive candidiasis, can cause high mortality rates in immunocompromised patients. Photodynamic antimicrobial chemotherapy (PACT) is a promising approach for controlling infections caused by biofilm-associated C. albicans. This study shows the effect of Elsinochrome A (EA) against different stages of C. albicans biofilms in vitro by XTT reduction assay and crystal violet staining. The mechanism of action of EA on C. albicans biofilm was analyzed with flow cytometry, confocal laser microscopy, and the Real-Time Quantitative Reverse Transcription PCR (qRT-PCR). EA-mediated PACT significantly reduced the viability of C. albicans, with an inhibition rate on biofilm of 89.38% under a concentration of 32 μg/mL EA. We found that EA could not only inhibit the adhesion of C. albicans in the early stage of biofilm formation, but that it also had good effects on pre-formed mature biofilms with a clearance rate of 35.16%. It was observed that EA-mediated PACT promotes the production of a large amount of reactive oxygen species (ROS) in C. albicans and down-regulates the intracellular expression of oxidative-stress-related genes, which further disrupted the permeability of cell membranes, leading to mitochondrial and nuclear damage. These results indicate that EA has good photodynamic antagonizing activity against the C. albicans biofilm, and potential clinical value.}, } @article {pmid36012773, year = {2022}, author = {Bravo-Chaucanés, CP and Vargas-Casanova, Y and Chitiva-Chitiva, LC and Ceballos-Garzon, A and Modesti-Costa, G and Parra-Giraldo, CM}, title = {Evaluation of Anti-Candida Potential of Piper nigrum Extract in Inhibiting Growth, Yeast-Hyphal Transition, Virulent Enzymes, and Biofilm Formation.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {8}, pages = {}, pmid = {36012773}, issn = {2309-608X}, support = {848-2019//Minciencias/ ; 08711-20//Pontificia Universidad Javeriana/ ; 792-2017//Call Scientific Ecosystem for I+D+i/ ; FP44842-221-2018//World Bank and the Vice Presidency of Research at Pontificia Universidad Javeriana/ ; 2019//Becas de Excelencia Doctoral del Bicentenario/ ; }, abstract = {Due to the increased incidence of fungal infections and the emergence of antifungal resistance mainly by Candida species, the need for safe and effective novel therapies is imperative. Consequently, plants and herbs are a powerful source to combat infections. Here, we evaluated the anti-Candida potential of an ethanolic extract from Piper nigrum. The phytochemical analysis of P. nigrum revealed bioactive compounds such as alkaloids, terpenoids, and tannis. Our results showed that P. nigrum extract suppressed the virulence factors of C. albicans strains, including hyphae formation in both liquid and solid media, reduced secretion of phospholipases/proteinases, and affected biofilm formation. Furthermore, the P. nigrum extract showed no hemolytic effect in vitro and exhibited reduced cytotoxicity on Vero cells and G. mellonella larvae at concentrations that inhibited hyphae and biofilm in C. albicans. Moreover, the extract demonstrated antifungal activity against C. auris strains. In conclusion, the P. nigrum extract affected the growth and morphogenesis of Candida (even in resistant strains), demonstrating that this plant has an anti-candida activity and represents a promising resource for discovering novel antifungal compounds.}, } @article {pmid36012520, year = {2022}, author = {Swolana, D and Kępa, M and Kruszniewska-Rajs, C and Wojtyczka, RD}, title = {Antibiofilm Effect of Silver Nanoparticles in Changing the Biofilm-Related Gene Expression of Staphylococcus epidermidis.}, journal = {International journal of molecular sciences}, volume = {23}, number = {16}, pages = {}, pmid = {36012520}, issn = {1422-0067}, support = {PCN-2-019/K/0/K.//Medical University of Silesia/ ; }, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Biofilms ; Gene Expression ; Humans ; Iron-Dextran Complex ; *Metal Nanoparticles ; Polysaccharides, Bacterial/metabolism ; Silver/metabolism/pharmacology ; *Staphylococcal Infections/microbiology ; Staphylococcus epidermidis ; }, abstract = {Nowadays, antibiotic resistance is a major public health problem. Among staphylococci, infections caused by Staphylococcus epidermidis (S. epidermidis) are frequent and difficult to eradicate. This is due to its ability to form biofilm. Among the antibiotic substances, nanosilver is of particular interest. Based on this information, we decided to investigate the effect of nanosilver on the viability, biofilm formation and gene expression of the icaADBC operon and the icaR gene for biofilm and non-biofilm S. epidermidis strains. As we observed, the viability of all the tested strains decreased with the use of nanosilver at a concentration of 5 µg/mL. The ability to form biofilm also decreased with the use of nanosilver at a concentration of 3 µg/mL. Genetic expression of the icaADBC operon and the icaR gene varied depending on the ability of the strain to form biofilm. Low concentrations of nanosilver may cause increased biofilm production, however no such effect was observed with high concentrations. This confirms that the use of nanoparticles at an appropriately high dose in any future therapy is of utmost importance. Data from our publication confirm the antibacterial and antibiotic properties of nanosilver. This effect was observed phenotypically and also by levels of gene expression.}, } @article {pmid36012494, year = {2022}, author = {Slezak, C and Anderson, K and Hillock, T and Miller, M and Dungel, P and Kopp, O and Sterflinger, K and Slezak, P}, title = {Shockwaves Increase In Vitro Resilience of Rhizopus oryzae Biofilm under Amphotericin B Treatment.}, journal = {International journal of molecular sciences}, volume = {23}, number = {16}, pages = {}, pmid = {36012494}, issn = {1422-0067}, mesh = {*Amphotericin B/pharmacology ; Antifungal Agents/pharmacology ; Biofilms ; *Extracorporeal Shockwave Therapy/methods ; Mechanotransduction, Cellular ; Microbial Sensitivity Tests ; Rhizopus oryzae ; }, abstract = {Acoustical biophysical therapies, including ultrasound, radial pressure waves, and shockwaves, have been shown to harbor both a destructive and regenerative potential depending on physical treatment parameters. Despite the clinical relevance of fungal biofilms, little work exits comparing the efficacy of these modalities on the destruction of fungal biofilms. This study evaluates the impact of acoustical low-frequency ultrasound, radial pressure waves, and shockwaves on the viability and proliferation of in vitro Rhizopus oryzae biofilm under Amphotericin B induced apoptosis. In addition, the impact of a fibrin substrate in comparison with a traditional polystyrene well-plate one is explored. We found consistent, mechanically promoted increased Amphotericin B efficacy when treating the biofilm in conjunction with low frequency ultrasound and radial pressure waves. In contrast, shockwave induced effects of mechanotransduction results in a stronger resilience of the biofilm, which was evident by a marked increase in cellular viability, and was not observed in the other types of acoustical pressure waves. Our findings suggest that fungal biofilms not only provide another model for mechanistical investigations of the regenerative properties of shockwave therapies, but warrant future investigations into the clinical viability of the therapy.}, } @article {pmid36012475, year = {2022}, author = {Phuengmaung, P and Mekjaroen, J and Saisorn, W and Chatsuwan, T and Somparn, P and Leelahavanichkul, A}, title = {Rapid Synergistic Biofilm Production of Pseudomonas and Candida on the Pulmonary Cell Surface and in Mice, a Possible Cause of Chronic Mixed Organismal Lung Lesions.}, journal = {International journal of molecular sciences}, volume = {23}, number = {16}, pages = {}, pmid = {36012475}, issn = {1422-0067}, support = {CU-FRB65_hea [33] _040_30_21//Chulalongkorn University/ ; }, mesh = {Animals ; Biofilms ; *Candida/metabolism ; Cytokines/metabolism ; Lung/metabolism ; Mice ; Polysaccharides, Bacterial/metabolism ; Proteomics ; *Pseudomonas/metabolism ; Pseudomonas aeruginosa/physiology ; }, abstract = {Due to the possible co-presence of Pseudomonas aeruginosa and Candida albicans (the most common nosocomial pathogens) in lungs, rapid interkingdom biofilm production is possible. As such, PA+CA produced more dominant biofilms on the pulmonary epithelial surface (NCI-H292) (confocal fluorescent extracellular matrix staining) with dominant psl upregulation, as demonstrated by polymerase chain reaction (PCR), after 8 h of experiments than PA alone. With a proteomic analysis, rhamnosyltransferase RhlB protein (Psl-associated quorum-sensing protein) was found to be among the high-abundance proteins in PA+CA than in PA biofilms, supporting psl-mediated biofilms in PA+CA on the cell surface. Additionally, PA+CA increased supernatant cytokines (IL-8 and IL-13, but not TNF-α, IL-6, and IL-10) with a similar upregulation of TLR-4, TLR-5, and TLR-9 (by PCR) compared with PA-stimulated cells. The intratracheal administration of PA+CA induced a greater severity of sepsis (serum creatinine, alanine transaminase, serum cytokines, and histology score) and prominent biofilms (fluorescent staining) with psl upregulation (PCR). In comparison with PA+CA biofilms on glass slides, PA+CA biofilms on biotic surfaces were more prominent (fluorescent staining). In conclusion, PA+CA induced Psl-predominant biofilms on the pulmonary cell surface and in mice with acute pneumonia, and these biofilms were more prominent than those induced by PA alone, highlighting the impact of Candida on rapid interkingdom biofilm production.}, } @article {pmid36010540, year = {2022}, author = {Zhang, Y and Ding, Z and Shao, C and Xie, J}, title = {Chlorophyllin-Based 405 nm Light Photodynamic Improved Fresh-Cut Pakchoi Quality at Postharvest and Inhibited the Formation of Biofilm.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {16}, pages = {}, pmid = {36010540}, issn = {2304-8158}, support = {20DZ2292200//Shanghai Green Leaf Vegetable Industry Technology System Project/ ; 19DZ1207503//Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation/ ; }, abstract = {The aim of this study was to evaluate the effect of chlorophyllin-based photodynamic inactivation (Chl-PDI) on biofilm formation and fresh-cut pakchoi quality during storage. Firstly, Chl-based PDI reduced the amount of biofilm in an in vivo experiment and inactivated the food spoilage bacteria. Antibacterial mechanism analysis indicated that the bacterial extracellular polysaccharides and extracellular proteins were vulnerable targets for attacks by the Chl-based PDI. Then, the food spoilage microorganisms (Pseudomonas reinekei and Pseudomonas palleroniana) were inoculated onto the surface of fresh-cut pakchoi. We used chlorophyllin (1 × 10[-5] mol/L) and 405 nm light (22.27 J/cm[2] per day) to investigate the effect of Chl-based PDI treatment on fresh-cut pakchoi quality during storage. The results showed that Chl-based PDI increased the visual quality and the content of chlorophyll, VC, total soluble solids, and SOD activity and decreased the occurrence of leaf yellowing and POD activity. These suggest that Chl-based PDI can be used for the preservation of fresh-cut pakchoi and has the potential to inhibit biofilm formation of food spoilage bacteria. It is of great significance for the effective processing and traditional vegetable preservation.}, } @article {pmid36010469, year = {2022}, author = {Zhou, F and Wang, D and Hu, J and Zhang, Y and Tan, BK and Lin, S}, title = {Control Measurements of Escherichia coli Biofilm: A Review.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {16}, pages = {}, pmid = {36010469}, issn = {2304-8158}, support = {31801649//National Natural Science Foundation of China/ ; 2016YFD0400403//"13th Five Year Plan" National Key Research and Development Project/ ; 2020I0010//Natural Science Foundation of Fujian Province/ ; ZZ2019ZD18//Science and Technology Major Project of Zhangzhou/ ; CXZX2018063; CXZX2019100S; CXZX2019101S//Special Funds for Science and Technology Innovation of FAFU/ ; }, abstract = {Escherichia coli (E. coli) is a common pathogen that causes diarrhea in humans and animals. In particular, E. coli can easily form biofilm on the surface of living or non-living carriers, which can lead to the cross-contamination of food. This review mainly summarizes the formation process of E. coli biofilm, the prevalence of biofilm in the food industry, and inhibition methods of E. coli biofilm, including chemical and physical methods, and inhibition by bioactive extracts from plants and animals. This review aims to provide a basis for the prevention and control of E. coli biofilm in the food industry.}, } @article {pmid36009913, year = {2022}, author = {Hosida, TY and Pessan, JP and Cavazana, TP and Sampaio, C and de Morais, LA and Monteiro, DR and Delbem, ACB}, title = {Effects of Sodium Hexametaphosphate and Fluoride on the pH and Inorganic Components of Streptococcus mutans and Candida albicans Biofilm after Sucrose Exposure.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {8}, pages = {}, pmid = {36009913}, issn = {2079-6382}, support = {001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 88881.030445/2013-01//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {In order to improve the anticaries effects of fluoridated products, the supplementation of these products has been considered a promising alternative for caries control. This study evaluated the effects of sodium hexametaphosphate (HMP) and/or fluoride (F) on the inorganic components and pH of Streptococcus mutans and Candida albicans dual-species biofilms. The biofilms were treated 72, 78, and 96 h after the beginning of their formation with 0.25, 0.5, or 1% HMP-containing solutions with or without F (500 ppm, as sodium fluoride). F-containing solutions (500 ppm and 1100 ppm) and artificial saliva were used as controls. The biofilms were exposed to a 20% sucrose solution after the third treatment. Along with the biofilm pH, the concentrations of F, calcium, phosphorus (P), and HMP were determined. HMP, combined with F, increased F levels and decreased P levels in the biofilm fluid compared to that of the solution with 500 ppm F. Exposure to sucrose decreased the concentrations of all ions in the biomass, except for HMP; 1% HMP, combined with F, promoted the highest pH. It can be concluded that HMP affected the inorganic composition of the biofilm and exerted a buffering effect on the biofilm pH.}, } @article {pmid36008671, year = {2022}, author = {Hereidia, M and Andes, D}, title = {Production and Isolation of the Candida Species Biofilm Extracellular Matrix.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2542}, number = {}, pages = {257-268}, pmid = {36008671}, issn = {1940-6029}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida ; Candida albicans ; *Candidiasis/microbiology ; Extracellular Matrix ; Extracellular Polymeric Substance Matrix ; Gas Chromatography-Mass Spectrometry ; Renal Dialysis ; }, abstract = {The extracellular matrix (ECM) is a dynamic structure comprising of all four classes of macromolecules. In the biofilm setting, this matrix is key to the survival of microbial communities by conferring to biofilms both structural integrity and protection against diverse environmental insults. In Candida spp., this matrix contributes to pathogenesis by conferring to biofilms both drug resistance and protection against immune attack. Understanding the biochemical nature of the matrix and its individual components is critical to the development of novel diagnostics and antifungal strategies against persistent Candida biofilm infections. Therefore, efficient methods for ECM isolation are required. The two matrix isolation protocols described herein are adapted for both small- and large-scale isolation of biofilm matrix. Both procedures involve seeding of biofilms in either 6-well plates or large-surface-area roller bottles, followed by cell adhesion and biofilm maturation for 2 days with continuous motion. In both cases, the matrix is separated from the biomass via sonication, a step which gently and effectively removes the matrix without disturbing the fungal cell wall. The large-scale protocol includes additional filtration, lyophilization, and dialysis steps to yield purified matrix material sufficient for numerous biochemical, structural, and functional assays. Small-scale isolation yields enough matrix for gas chromatography (GC), total carbohydrate quantification via the phenol-sulfuric acid method, and total protein quantification via the bicinchoninic acid (BCA) assay. Large-scale isolation yields enough matrix to perform NMR spectroscopy, liquid chromatography, mass spectrometry, and nucleic acid sequencing. These protocols have been adapted for use in Candida species but may be adapted for other biofilm-forming fungal species and bacteria.}, } @article {pmid36008667, year = {2022}, author = {Uppuluri, P}, title = {A Simple Method for Growth of Candida albicans Biofilms Under Continuous Media Flow and for Recovery of Biofilm Dispersed Cells.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2542}, number = {}, pages = {219-224}, pmid = {36008667}, issn = {1940-6029}, mesh = {*Biofilms ; *Candida albicans ; Stress, Mechanical ; }, abstract = {Majority of nosocomial infections are associated with biofilms growing on indwelling medical devices. These biofilms are nourished by a continuous flow of body fluids and subjected to shear stress forces. Cells dispersed from C. albicans biofilms are highly virulent and developmentally distinct from their parent biofilms. To study biofilm dispersed cells, it becomes imperative to isolate newly dispersed cells using a flow biofilm model. In this chapter, we detail the methods underlying assembly and workings of a simple flow biofilm model using materials commonly available in most microbiological laboratories. Biofilms developed using this system are robust and particularly suitable for studies requiring large amounts of biofilm (dispersed) cells for downstream analyses. Importantly, this apparatus mimics in vivo flow conditions, thereby making it a physiologically relevant model.}, } @article {pmid36007573, year = {2022}, author = {Rath, S and Palit, K and Das, S}, title = {Variable pH and subsequent change in pCO2 modulates the biofilm formation, synthesis of extracellular polymeric substances, and survivability of a marine bacterium Bacillus stercoris GST-03.}, journal = {Environmental research}, volume = {214}, number = {Pt 4}, pages = {114128}, doi = {10.1016/j.envres.2022.114128}, pmid = {36007573}, issn = {1096-0953}, mesh = {*Bacillus ; Bacteria/metabolism ; Biofilms ; Ecosystem ; *Extracellular Polymeric Substance Matrix ; Hydrogen-Ion Concentration ; Seawater ; }, abstract = {Biofilm-forming bacteria adhere to the substrates and engage in the nutrient cycling process. However, environmental conditions may interrupt the biofilm formation ability, which ultimately may affect various biogeochemical cycles. The present study reports the effect of varying pH and subsequent change in pCO2 on the survivability, biofilm formation, and synthesis of extracellular polymeric substances (EPS) of a biofilm-forming marine bacterium Bacillus stercoris GST-03 isolated from the Bhitarkanika mangrove ecosystem, Odisha, India. Understanding the pH-dependent alteration in EPS constituents, and associated functional groups of a marine bacterium will provide better insight into the adaptability of the bacteria in future ocean acidification scenarios. The strain was found to tolerate and form biofilm up to pH 4, with the maximum biofilm formation at pH 6. EPS yield and the synthesis of the key components of the EPS, including carbohydrate, protein, and lipid, were found maximum at pH 6. Changes in biofilm formation patterns and various topological parameters at varying pH/pCO2 conditions were observed. A cellular chaining pattern was observed at pH 4, and maximum biofilm formation was obtained at pH 6 with biomass of 5.28582 ± 0.5372 μm[3]/μm[2] and thickness of 9.982 ± 1.5288 μm. Structural characterization of EPS showed changes in various functional groups of constituent macromolecules with varying pH. The amorphous nature of the EPS and the changes in linkages and associated functional groups (-R2CHOR, -CH3, and -CH2) with pH variation was confirmed. EPS showed a two-step degradation with a maximum weight loss of 59.147% and thermal stability up to 480 °C at pH 6. The present work efficiently demonstrates the role of EPS in providing structural and functional stability to the biofilm in varying pH conditions. The findings will provide a better understanding of the adaptability of marine bacteria in the future effect of ocean acidification.}, } @article {pmid36007343, year = {2022}, author = {Misic, C and Rafael, A and Covazzi Harriague, A}, title = {Organic matter production and recycling in marine biofilm developing on common and new plastics.}, journal = {Marine environmental research}, volume = {180}, number = {}, pages = {105729}, doi = {10.1016/j.marenvres.2022.105729}, pmid = {36007343}, issn = {1879-0291}, mesh = {*Biodegradable Plastics ; Biofilms ; Carbon ; Nitriles ; *Plastics ; Polystyrenes ; }, abstract = {To face the recent pandemic and comply with international legislation, new plastic objects (surgical masks, nitrile gloves, compostable plastics) have been produced, with a significant increase of their input into the marine environment, together with other common plastics. Given that floating plastic provides a suitable surface for settlement of micro-organism, biofilm accretion was studied in laboratory experiments. The characteristics of biofilm in terms of organic matter production and recycling were evaluated under natural and forced conditions, some of them resembling anthropogenic-affected states (eutrophication) and others environmental variability (darkness and oligotrophy). Under natural conditions, the different plastics, due to their structure and composition, hosted different biofilms. Thicker biofilm was observed on surgical mask and compostable plastic (organic carbon maxima of 35.0 ± 4.7 μg cm[-2] and 4.3 ± 0.8 μg cm[-2], respectively). Compostable plastic hosted a higher carbohydrate quantity than polyethylene terephthalate, polystyrene and nitrile (on average 8.0 ± 0.8 μg cm[-2] vs 3.6 ± 1.6 μg cm[-2] for the others). The multi-layer structure of masks and the composition of compostable plastic were the main factors responsible for these differences. Polystyrene and nitrile hosted a higher photoautotrophic biomass, with chlorophyll-a maxima higher than 50 μg cm[-2] vs values lower than 10 μg cm[-2] for compostable plastic. Inhibition of photosynthetic activity (darkness) allowed a greater biofilm mass, which in natural aphotic zone, may enhance the sinking of plastics. The large availability of carbon (eutrophication) allowed thicker biofilms, providing seawater of additional organic matter load. These biofilms could protect pathogenic organisms, especially on disposable protection equipment, allowing a larger spreading.}, } @article {pmid36006972, year = {2022}, author = {Ballash, GA and Mollenkopf, DF and Diaz-Campos, D and van Balen, JC and Cianciolo, RE and Wittum, TE}, title = {Pathogenomics and clinical recurrence influence biofilm capacity of Escherichia coli isolated from canine urinary tract infections.}, journal = {PloS one}, volume = {17}, number = {8}, pages = {e0270461}, pmid = {36006972}, issn = {1932-6203}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Dogs ; Escherichia coli/genetics ; *Escherichia coli Infections/epidemiology ; Retrospective Studies ; *Urinary Tract Infections/drug therapy ; }, abstract = {Biofilm formation enhances bacteria's ability to colonize unique niches while protecting themselves from environmental stressors. Escherichia coli that colonize the urinary tract can protect themselves from the harsh bladder environment by forming biofilms. These biofilms promote persistence that can lead to chronic and recurrent urinary tract infections (UTI). While biofilm formation is frequently studied among urinary E. coli, its association with other pathogenic mechanisms and adaptations in certain host populations remains poorly understood. Here we utilized whole genome sequencing and retrospective medical record analysis to investigate associations between the population structure, phenotypic resistance, resistome, virulome, and patient demographic and clinical findings of 104 unique urinary E. coli and their capacity to form biofilms. We show that population structure including multilocus sequence typing and Clermont phylogrouping had no association with biofilm capacity. Among clinical factors, exposure to multiple antibiotics within that past 30 days and a clinical history of recurrent UTIs were positively associated with biofilm formation. In contrast, phenotypic antimicrobial reduced susceptibility and corresponding acquired resistance genes were negatively associated with biofilm formation. While biofilm formation was associated with increased virulence genes within the cumulative virulome, individual virulence genes did not influence biofilm capacity. We identified unique virulotypes among different strata of biofilm formation and associated the presence of the tosA/R-ibeA gene combination with moderate to strong biofilm formation. Our findings suggest that E. coli causing UTI in dogs utilize a heterogenous mixture of virulence genes to reach a biofilm phenotype, some of which may promote robust biofilm capacity. Antimicrobial use may select for two populations, non-biofilm formers that maintain an arsenal of antimicrobial resistance genes to nullify treatment and a second that forms durable biofilms to avoid therapeutic insults.}, } @article {pmid36006345, year = {2022}, author = {Lee, YJ and Lee, YJ}, title = {Characterization of Biofilm Producing Coagulase-Negative Staphylococci Isolated from Bulk Tank Milk.}, journal = {Veterinary sciences}, volume = {9}, number = {8}, pages = {}, pmid = {36006345}, issn = {2306-7381}, abstract = {Coagulase-negative staphylococci (CoNS) are considered less virulent as they do not produce a large number of toxic enzymes and toxins; however, they have been increasingly recognized as an important cause of bovine mastitis. In particular, the ability to form biofilms appears to be an important factor in CoNS pathogenicity, and it contributes more resistance to antimicrobials. The aim of this study was to investigate the pathogenic potential by assessing the biofilm-forming ability of CoNS isolated from normal bulk tank milk using the biofilm formation assay and to analyze the biofilm-associated resistance to antimicrobial agents using the disc diffusion method. One hundred and twenty-seven (78.4%) among 162 CoNS showed the ability of biofilm formation, and all species showed a significantly high ability of biofilm formation (p < 0.05). Although the prevalence of weak biofilm formers (39.1% to 80.0%) was significantly higher than that of other biofilm formers in all species (p < 0.05), the prevalence of strong biofilm formers was significantly higher in Staphylococcus haemolyticus (36.4%), Staphylococcus chromogenes (24.6%), and Staphylococcus saprophyticus (21.7%) (p < 0.05). Also, 4 (11.4%) among 35 non-biofilm formers did not harbor any biofilm-associated genes, whereas all 54 strong or moderate biofilm formers harbored 1 or more of these genes. The prevalence of MDR was significantly higher in biofilm formers (73.2%) than in non-formers (20.0%) (p < 0.05). Moreover, the distribution of MDR in strong or moderate biofilm formers was 81.5%, which was significantly higher than in weak (67.1%) and non-formers (20.0%) (p < 0.05). Our results indicated that various CoNS isolated from bulk tank milk, not from bovine with mastitis, have already showed a high ability to form biofilms, while also displaying a high prevalence of MDR.}, } @article {pmid36005689, year = {2022}, author = {Jiang, M and Zhang, Y and Zhang, J and Dai, X and Li, H and Zhang, X and Wu, Z and Zheng, J}, title = {Model Evaluation of the Microbial Metabolic Processes in a Hydrogen-Based Membrane Biofilm Reactor for Simultaneous Bromate and Nitrate Reduction.}, journal = {Membranes}, volume = {12}, number = {8}, pages = {}, pmid = {36005689}, issn = {2077-0375}, support = {2022GXNSFFA035033//Guangxi Natural Science Foundation/ ; 52000046//National Natural Science Foundation of China/ ; 52100034//National Natural Science Foundation of China/ ; 51878197//National Natural Science Foundation of China/ ; GuiKe AD20297009//Special Project of Guangxi Science and Technology Base and Talent/ ; GuiKe AD20297007//Special Project of Guangxi Science and Technology Base and Talent/ ; 2022KY0179//Middle-aged and Young Teachers' Basic Ability Promotion Project of Guangxi/ ; 2021KY0221//Middle-aged and Young Teachers' Basic Ability Promotion Project of Guangxi/ ; 2020KY05039//Middle-aged and Young Teachers' Basic Ability Promotion Project of Guangxi/ ; }, abstract = {The H2-based membrane biofilm reactor (H2-MBfR) has been acknowledged as a cost-effective microbial reduction technology for oxyanion removal from drinking water sources, but it remains unknown how the evolution of biofilm characteristics responds to the changing critical operating parameters of the H2-MBfR for simultaneous bromate (BrO3[-]) and nitrate (NO3[-]) elimination. Therefore, an expanded multispecies model, applicable to mechanistically interpret the bromate-reducing bacteria (BRB)- and denitrifying bacteria (DNB)-dominated metabolic processes in the biofilm of the H2-MBfR, was developed in this study. The model outputs indicate that (1) increased BrO3[-] loading facilitated the metabolism of BRB by increasing BRB fraction and BrO3[-] gradients in the biofilm, but had a marginal influence on NO3[-] reduction; (2) H2 pressure of 0.04 MPa enabled the minimal loss of H2 and the extension of the active region of BRB and DNB in the biofilm; (3) once the influent NO3[-] concentration was beyond 10 mg N/L, the fraction and activity of BRB significantly declined; (4) BRB was more tolerant than DNB for the acidic aquatic environment incurred by the CO2 pressure over 0.02 MPa. The results corroborate that the degree of microbial competition for substrates and space in the biofilm was dependent on system operating parameters.}, } @article {pmid36004331, year = {2022}, author = {Lin, S and Chen, S and Li, L and Cao, H and Li, T and Hu, M and Liao, L and Zhang, LH and Xu, Z}, title = {Genome characterization of a uropathogenic Pseudomonas aeruginosa isolate PA_HN002 with cyclic di-GMP-dependent hyper-biofilm production.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {956445}, pmid = {36004331}, issn = {2235-2988}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; *Escherichia coli Proteins/genetics ; Gene Expression Regulation, Bacterial ; Phosphoric Diester Hydrolases/metabolism ; *Pseudomonas aeruginosa/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa can cause various types of infections and is one of the most ubiquitous antibiotic-resistant pathogens found in healthcare settings. It is capable of adapting to adverse conditions by transforming its motile lifestyle to a sessile biofilm lifestyle, which induces a steady state of chronic infection. However, mechanisms triggering the lifestyle transition of P. aeruginosa strains with clinical significance are not very clear. In this study, we reported a recently isolated uropathogenic hyper-biofilm producer PA_HN002 and characterized its genome to explore genetic factors that may promote its transition into the biofilm lifestyle. We first showed that high intracellular c-di-GMP content in PA_HN002 gave rise to its attenuated motilities and extraordinary strong biofilm. Reducing the intracellular c-di-GMP content by overexpressing phosphodiesterases (PDEs) such as BifA or W909_14950 converted the biofilm and motility phenotypes. Whole genome sequencing and comprehensive analysis of all the c-di-GMP metabolizing enzymes led to the identification of multiple mutations within PDEs. Gene expression assays further indicated that the shifted expression profile of c-di-GMP metabolizing enzymes in PA_HN002 might mainly contribute to its elevated production of intracellular c-di-GMP and enhanced biofilm formation. Moreover, mobile genetic elements which might interfere the endogenous regulatory network of c-di-GMP metabolism in PA_HN002 were analyzed. This study showed a reprogrammed expression profile of c-di-GMP metabolizing enzymes which may promote the pathoadaption of clinical P. aeruginosa into biofilm producers.}, } @article {pmid36003939, year = {2022}, author = {Brandani, J and Peter, H and Busi, SB and Kohler, TJ and Fodelianakis, S and Ezzat, L and Michoud, G and Bourquin, M and Pramateftaki, P and Roncoroni, M and Lane, SN and Battin, TJ}, title = {Spatial patterns of benthic biofilm diversity among streams draining proglacial floodplains.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {948165}, pmid = {36003939}, issn = {1664-302X}, abstract = {Glacier shrinkage opens new proglacial terrain with pronounced environmental gradients along longitudinal and lateral chronosequences. Despite the environmental harshness of the streams that drain glacier forelands, their benthic biofilms can harbor astonishing biodiversity spanning all domains of life. Here, we studied the spatial dynamics of prokaryotic and eukaryotic photoautotroph diversity within braided glacier-fed streams and tributaries draining lateral terraces predominantly fed by groundwater and snowmelt across three proglacial floodplains in the Swiss Alps. Along the lateral chronosequence, we found that benthic biofilms in tributaries develop higher biomass than those in glacier-fed streams, and that their respective diversity and community composition differed markedly. We also found spatial turnover of bacterial communities in the glacier-fed streams along the longitudinal chronosequence. These patterns along the two chronosequences seem unexpected given the close spatial proximity and connectivity of the various streams, suggesting environmental filtering as an underlying mechanism. Furthermore, our results suggest that photoautotrophic communities shape bacterial communities across the various streams, which is understandable given that algae are the major source of organic matter in proglacial streams. Overall, our findings shed new light on benthic biofilms in proglacial streams now changing at rapid pace owing to climate-induced glacier shrinkage.}, } @article {pmid36003935, year = {2022}, author = {Long, L and Sulaiman, JE and Xiao, Y and Cheng, A and Wang, R and Malit, JJ and Wong, WC and Liu, W and Li, YX and Chen, F and Lam, H and Qian, PY}, title = {Mode of action of elasnin as biofilm formation eradicator of methicillin-resistant Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {967845}, pmid = {36003935}, issn = {1664-302X}, abstract = {Biofilm is made up of microbes and their extracellular matrix, making microorganisms highly tolerant, resistant, and resilient to a wide range of antimicrobials. Biofilm treatment with conventional antimicrobial agents can accelerate the evolution and spread of resistance due to the reduced efficacy and increased gene transfer and differentiation within biofilms. Therefore, effective biofilm-targeting compounds are currently highly sought after. In the present study, we identified elasnin as a potent biofilm-targeting compound against methicillin-resistant Staphylococcus aureus (MRSA). Elasnin effectively inhibited biofilm formation and especially eradicated the pre-formed biofilms of MRSA with low cytotoxicity and low risk of resistance development and retains its activity in a chronic wound biofilms model. A comprehensive mechanistic study using multi-omics and confocal and scanning electron microscopy revealed that elasnin induced the biofilm matrix destruction in a time-dependent manner and interfered with the cell division during the exponential phase, primarily by repressing the expression of virulence factors. Cells released from the elasnin-treated biofilms exhibited a defective appearance and became more sensitive to beta-lactam antibiotic penicillin G. Through gene overexpression and deletion assay, we discovered the key role of sarZ during elasnin-induced biofilm eradication. Overall, the present study identified elasnin as a potent biofilm eradicator against MRSA that harbors potential to be developed for biofilm removal and chronic wound treatment, and provided new insights into the molecular targets for biofilm eradication in MRSA.}, } @article {pmid36002793, year = {2022}, author = {Ababneh, Q and Abu Laila, S and Jaradat, Z}, title = {Prevalence, genetic diversity, antibiotic resistance and biofilm formation of Acinetobacter baumannii isolated from urban environments.}, journal = {Journal of applied microbiology}, volume = {133}, number = {6}, pages = {3617-3633}, doi = {10.1111/jam.15795}, pmid = {36002793}, issn = {1365-2672}, support = {20210309//Jordan University of Science and Technology/ ; }, mesh = {Humans ; *Acinetobacter baumannii ; *Acinetobacter Infections/microbiology ; Prevalence ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Cross Infection/microbiology ; Drug Resistance, Multiple, Bacterial/genetics ; Biofilms ; Genetic Variation ; }, abstract = {AIM: Acinetobacter baumannii is a well-known nosocomial pathogen that has been isolated from different clinical sources. This pathogen also causes community-acquired infections, with mortality rates as high as 64%. The exact natural habitat of this bacterium is still unknown. In this study, we investigated the prevalence of A. baumannii in diverse soil and high-touch surface samples collected from a university campus, malls, parks, hypermarkets and produce markets, roundabout playground slides and bank ATMs.

METHODS AND RESULTS: All obtained isolates were characterized for their antibiotic susceptibility, biofilm formation capacities, and were typed by multi-locus sequence analysis. A total of 63 A. baumannii isolates were recovered, along with 46 Acinetobacter pittii and 8 Acinetobacter nosocomialis isolates. Sequence typing revealed that 25 A. baumannii isolates are novel strains. Toilets and sink washing basins were the most contaminated surfaces, accounting for almost 50% of the isolates. A number of A. baumannii (n = 10), A. pittii (n = 19) and A. nosocomialis (n = 5) isolates were recovered from handles of shopping carts and baskets. The majority of isolates were strong biofilm formers and 4 isolates exhibited a multi-drug resistant phenotype.

CONCLUSIONS: Our study is the first to highlight community restrooms and shopping carts as potential reservoirs for pathogenic Acinetobacter species. Further studies are required to identify the reasons associated with the occurrence of A. baumannii inside restrooms. Proper disinfection of community environmental surfaces and spreading awareness about the importance of hand hygiene may prevent the dissemination of pathogenic bacteria within the community.

Serious gaps remain in our knowledge of how A. baumannii spreads to cause disease. This study will advance our understanding of how this pathogen spreads between healthcare and community environments. In addition, our findings will help healthcare decision-makers implement better measures to control and limit further transmission of A. baumannii.}, } @article {pmid36002414, year = {2022}, author = {Xu, H and Liu, J and Zhang, Z and Tao, Q and Huang, Z and Pan, Y and Zhao, Y}, title = {[Animal models in bacterial biofilm research: a review].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {38}, number = {8}, pages = {2840-2856}, doi = {10.13345/j.cjb.220143}, pmid = {36002414}, issn = {1872-2075}, mesh = {Animals ; Anti-Bacterial Agents ; Bacteria ; *Bacterial Infections ; Biofilms ; Caenorhabditis elegans ; Disease Models, Animal ; *Drosophila melanogaster ; Mammals ; Mice ; Models, Animal ; Rabbits ; Swine ; Zebrafish ; }, abstract = {Biofilm formation is closely related to pathogenicity and antibiotic resistance of bacteria, and plays important roles in a number of chronic and subchronic infections. Animal models are widely used in the research of bacterial biofilm-associated infections, and provide a powerful scientific tool for investigating its pathogenesis and control strategies. This review summarized the application of mammalian models (e.g. mouse, rabbit, and pig) and non-mammalian models (e.g. Drosophila melanogaster, Zebrafish, and Caenorhabditis elegans) in bacterial biofilm studies, and prospects the application of animal models in biofilm. This review may facilitate the selection of suitable animal models in the study of biofilm-associated infections, so as to prevent and control the potential adverse effects.}, } @article {pmid36002412, year = {2022}, author = {He, Y and Jia, W and Chi, S and Meng, Q and Chen, Y and Wang, X}, title = {[Research progress of c-di-GMP in the regulation of Escherichia coli biofilm].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {38}, number = {8}, pages = {2811-2820}, doi = {10.13345/j.cjb.220094}, pmid = {36002412}, issn = {1872-2075}, mesh = {Bacterial Proteins/genetics ; Biofilms ; Cyclic GMP/analogs & derivatives ; *Escherichia coli/genetics/metabolism ; *Escherichia coli Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {Escherichia coli biofilm is a complex membrane aggregation produced by the adhesion and secretion of extracellular polymeric substances by E. coli cells aggregated on specific media. Pathogenic E. coli will evade the immune system and the impact of various harmful factors in the environment after the formation of biofilm, causing sustained and even fatal damage to the host. Cyclic diguanosine monophosphate (c-di-GMP) is a second messenger ubiquitous in bacteria and plays a crucial role in regulating biofilm formation. This paper reviewed the recent studies about the role of c-di-GMP in the movement, adhesion, and EPS production mechanism of E. coli during biofilm formation, aiming to provide a basis for inhibiting E. coli biofilm from the perspective of c-di-GMP.}, } @article {pmid35999263, year = {2022}, author = {Qi, L and Liang, R and Duan, J and Song, S and Pan, Y and Liu, H and Zhu, M and Li, L}, title = {Synergistic antibacterial and anti-biofilm activities of resveratrol and polymyxin B against multidrug-resistant Pseudomonas aeruginosa.}, journal = {The Journal of antibiotics}, volume = {75}, number = {10}, pages = {567-575}, pmid = {35999263}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Bacterial Infections/drug therapy ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; *Polymyxin B/pharmacology ; Polymyxins/pharmacology ; Pseudomonas aeruginosa ; Resveratrol/pharmacology ; }, abstract = {Bacterial infection caused by multidrug-resistant Pseudomonas aeruginosa has become a challenge in clinical practice. Polymyxins are used as the last resort agent for otherwise untreatable Gram-negative bacteria, including multidrug-resistant P.aeruginosa. However, pharmacodynamic (PD) and pharmacokinetic (PK) data on polymyxins suggest that polymyxin monotherapy is unlikely to generate reliably efficacious plasma concentrations. Also, polymyxin resistance has been frequently reported, especially among multidrug-resistant P.aeruginosa, which further limits its clinical use. A strategy for improving the antibacterial activity of polymyxins and preventing the development of polymyxin resistance is to use polymyxins in combination with other agents. In this study, we have demonstrated that resveratrol, a well tolerated compound, has synergistic effects when tested in vitro with polymyxin B on antibacterial and anti-biofilm activities. However, its' systemic use is limited as the required high plasma levels of resveratrol are not achievable. This suggests that it could be a partner for the combination therapy of polymyxin B in the treatment of topical bacterial infection caused by MDR P.aeruginosa.}, } @article {pmid35998684, year = {2022}, author = {Miao, F and Tai, Z and Wang, Y and Zhu, Q and Fang, JK and Hu, M}, title = {Tachyplesin I Analogue Peptide as an Effective Antimicrobial Agent against Candida albicans-Staphylococcus aureus Poly-Biofilm Formation and Mixed Infection.}, journal = {ACS infectious diseases}, volume = {8}, number = {9}, pages = {1839-1850}, doi = {10.1021/acsinfecdis.2c00080}, pmid = {35998684}, issn = {2373-8227}, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Biofilms ; Candida albicans ; *Coinfection/microbiology ; DNA-Binding Proteins ; Mice ; Peptides, Cyclic ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; }, abstract = {Microbial biofilms are difficult to tackle in many infectious diseases. Candida albicans and Staphylococcus aureus are prevalent symbiotic strains in polymicrobial biofilms, which showed enhanced antimicrobial resistance and made identifying effective treatment techniques more difficult. The antibiofilm abilities of tachplesin I analogue peptide (TP11A) and tachplesin I were investigated quantitatively in this study. Both inhibited C. albicans monomicrobial, S. aureus monomicrobial, and C. albicans-S. aureus polymicrobial biofilms quite well. TP11A suppressed the biofilm- and virulence-related genes of C. albicans (hwp 1) and S. aureus (ica A, fnb B, agr A, hla, nor A, and sig B) in the mixed biofilm, according to quantitative reverse transcription polymerase chain reaction analysis. We created an injectable thermosensitive in situ PLEL@TP11A gel system by simply adding TP11A into poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PLEL). Using C. albicans-S. aureus mixed infected wound models of mice, the in vivo therapeutic effect of TP11A and PLEL@TP11A in polymicrobial infections was investigated. The findings revealed that TP11A and PLEL@TP11A could efficiently reduce bacterial and fungal burden in wound infections, as well as accelerated wound healing. Based on above findings, TP11A might be an effective antimicrobial against C. albicans-S. aureus poly-biofilm formation and mixed infection.}, } @article {pmid35996675, year = {2022}, author = {Dhiman, S and Baliyan, N and Maheshwari, DK}, title = {Appraisal of biofilm forming bacteria in developing buffalo dung-based bioformulation coupled to promote yield of Foeniculum vulgare Mill.}, journal = {3 Biotech}, volume = {12}, number = {9}, pages = {234}, pmid = {35996675}, issn = {2190-572X}, abstract = {Chemical fertilizers impart deleterious effects on crop productivity and its nutrients which is a serious concern among agriculturist. Current research focuses on the commercial preparation of an eco-friendly and cost-effective bioformulation using buffalo dung slurry and beneficial plant growth-promoting (PGP) and biofilm forming strains. 40 strains were isolated from buffalo dung showing PGP activities. Among them, 03 strains were further selected to sequence by 16S rRNA technology and identified as Pseudomonas aeruginosa BUFF12, Proteus mirabilis BUFF14, Enterobacter xiangfangensis BUFF38. The strains were used for consortium preparation on the basis of increase in PGP activity. The consortium of strains increases in vitro PGP attributes at different percentage, i.e., 22% increase in IAA production, 10% increase in siderophore production, 5% increase in P- solubilization, 8% increase in K- solubilization, and 11% increase in S-oxidation. Three carrier materials, i.e., molasses of sugarcane, rice gruel, and buffalo dung slurry, were chosen to conduct the study. Among them, dung slurry proved to be an effective supportive material on the basis of their physico-chemical analysis and viability of strains for long-term storage. It maintained the population mixture of strains (9.4 × 10[8] cfu/ml) for 120 DAI followed by molasses (9.1 × 10[8] cfu/ml) and rice gruel (7.9 × 10[8] cfu/ml). These beneficial strains were further applied in field for crop productivity and slurry-based formulation with mixture of strains exhibited incredible plant growth after definite interval of time. Chemotactic activity proved these strains as strong root colonizers which was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM). This research disseminates a successful technology to develop an eco-friendly bioformulation of buffalo dung slurry augmenting the crop growth in an eco-friendly manner leading to sustainable agriculture.}, } @article {pmid35996024, year = {2022}, author = {Pei, J and Yu, H and Qiu, W and Mei, J and Xie, J}, title = {Antimicrobial Effect of Epigallocatechin Gallate Against Shewanella putrefaciens ATCC 8071: A Study Based on Cell Membrane and Biofilm.}, journal = {Current microbiology}, volume = {79}, number = {10}, pages = {297}, pmid = {35996024}, issn = {1432-0991}, support = {31972142//National Natural Science Foundation of China/ ; 20DZ2292200//Science and Technology Commission of Shanghai Municipality/ ; 19DZ2284000//Science and Technology Commission of Shanghai Municipality/ ; }, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Biofilms ; Catechin/analogs & derivatives ; Cell Membrane ; *Shewanella putrefaciens ; }, abstract = {The study was to evaluate the antimicrobial impacts and biofilm influences on epigallocatechin gallate (EGCG) against Shewanella putrefaciens ATCC 8071. The minimum inhibitory concentration (MIC) of EGCG on S. putrefaciens was 160 μg mL[-1]. The growth curve exhibited that EGCG had a good antimicrobial activity. EGCG caused damages to the bacterial cell wall and membrane based the intracellular component leakage and cell viability analysis. The damage to the membrane integrity by EGCG has been confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM shows deformation of shape, TEM shows cell membrane and wall damage, and the leakage of cytoplasmic material. The treatment with EGCG at 0.25× and 0.5× MIC resulted in decreased motility and elevated levels of oxidative stress, leading to an increase in biofilm formation. These results demonstrated that EGCG may be used as a natural preservative to reduce S. putrefaciens in fish during cold storage.}, } @article {pmid35995340, year = {2023}, author = {Schaffer, SD and Hutchison, CA and Rouchon, CN and Mdluli, NV and Weinstein, AJ and McDaniel, D and Frank, KL}, title = {Diverse Enterococcus faecalis strains show heterogeneity in biofilm properties.}, journal = {Research in microbiology}, volume = {174}, number = {1-2}, pages = {103986}, pmid = {35995340}, issn = {1769-7123}, support = {R01 AI141961/AI/NIAID NIH HHS/United States ; }, mesh = {*Enterococcus faecalis ; Periodic Acid ; *Biofilms ; Deoxyribonucleases ; Carbohydrates ; }, abstract = {Biofilm formation is important for Enterococcus faecalis to cause healthcare-associated infections. It is unclear how E. faecalis biofilms vary in parameters such as development and composition. To test the hypothesis that differences in biofilms exist among E. faecalis strains, we evaluated in vitro biofilm formation and matrix characteristics of five genetically diverse E. faecalis lab-adapted strains and clinical isolates (OG1RF, V583, DS16, MMH594, and VA1128). Biofilm formation of all strains was repressed in TSB+10% FBS. However, DMEM+10% FBS enhanced biofilm formation of clinical isolate VA1128. Crystal violet staining and fluorescence microscopy of biofilms grown on Aclar membranes demonstrated differences between OG1RF and VA1128 in biofilm development over a 48-h time course. None of the biofilms were dispersed by single treatments of sodium (meta)periodate, DNase, or Proteinase K alone, but the biofilm biomass of both OG1RF and DS16 was partially removed by a sequential treatment of sodium (meta)periodate and DNase. Reversing the treatment order was not effective, suggesting that the extracellular DNA targeted by DNase was obscured by carbohydrates that are susceptible to sodium (meta)periodate degradation. Fluorescent staining of biofilm matrix components further demonstrated that more carbohydrates bound by wheat germ agglutinin comprise OG1RF biofilms compared to VA1128 biofilms. This study highlights the existence of heterogeneity in biofilm properties among diverse E. faecalis strains, which may have implications for the design of novel anti-biofilm treatment strategies.}, } @article {pmid35995173, year = {2022}, author = {Li, Y and Su, J and Ali, A and Hao, Z and Li, M and Yang, W and Wang, Z}, title = {Simultaneous removal of nitrate and heavy metals in a biofilm reactor filled with modified biochar.}, journal = {The Science of the total environment}, volume = {851}, number = {Pt 2}, pages = {158175}, doi = {10.1016/j.scitotenv.2022.158175}, pmid = {35995173}, issn = {1879-1026}, mesh = {*Nitrates/chemistry ; Cadmium/chemistry ; Wastewater ; Calcium ; *Metals, Heavy/chemistry ; Nitrogen Oxides ; Biofilms ; Zinc/chemistry ; Calcium Carbonate/chemistry ; Denitrification ; Bioreactors ; }, abstract = {A biofilm reactor filled with chia seeds gum modified biochar was set up for the simultaneous removal of nitrate, cadmium and zinc from calcium-containing wastewater via denitrification and microbially-induced (calcium) carbonate precipitation. The reactor performance was studied under different conditions of pH, Cd concentration, and hydraulic retention time. The optimal removal efficiency of the reactor for NO3[-]-N, Ca[2+], Cd[2+], and Zn[2+] were 99.98, 79.89, 100, and 99.84 %, respectively. 3D-EEM indicated the aromatic compounds confirming the stability of the reactor. FTIR illustrated the presence of -OH, CaCO3, C-O-C, and C-O-H indicating the precipitation and role of gum in MICP. SEM confirmed that the seed crystal induced the repeated crystallization of free metal ions. XRD showed that heavy metals were removed in the form of CaCO3, CdCO3, ZnCO3, Ca3(PO3)2, Cd3(PO3)2, and Zn3(PO3)2 co-crystallization. SEM-EDS showed the composition and distribution of elements. High-throughput sequencing showed that Curpriavidus sp. GMF1 and Ochrobactrum sp. GMC12 were the dominant bacterial species, with powerful denitrification and MICP mineralization capabilities.}, } @article {pmid35995073, year = {2022}, author = {Gual-de-Torrella, A and Delgado-Valverde, M and Pérez-Palacios, P and Oteo-Iglesias, J and Rojo-Molinero, E and Macià, MD and Oliver, A and Pascual, Á and Fernández-Cuenca, F}, title = {Prevalence of the fimbrial operon mrkABCD, mrkA expression, biofilm formation and effect of biocides on biofilm formation in carbapenemase-producing Klebsiella pneumoniae isolates belonging or not belonging to high-risk clones.}, journal = {International journal of antimicrobial agents}, volume = {60}, number = {4}, pages = {106663}, doi = {10.1016/j.ijantimicag.2022.106663}, pmid = {35995073}, issn = {1872-7913}, mesh = {2-Propanol/metabolism/pharmacology ; Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/genetics/metabolism ; Benzalkonium Compounds/pharmacology ; Biofilms ; *Carbapenem-Resistant Enterobacteriaceae ; Clone Cells ; *Disinfectants/pharmacology ; Ethanol/metabolism/pharmacology ; Gentian Violet ; Humans ; *Klebsiella Infections ; Klebsiella pneumoniae/genetics/metabolism ; Microbial Sensitivity Tests ; Operon ; Povidone-Iodine/pharmacology ; Prevalence ; Sodium Hypochlorite/metabolism/pharmacology ; *Triclosan/pharmacology ; beta-Lactamases/metabolism ; }, abstract = {BACKGROUND: The role of mrkA adhesin expression, biofilm production, biofilm viability and biocides in the biofilm of carbapenemase-producing Klebsiella pneumoniae isolates was investigated.

METHODS: Seventeen isolates representing different sequence types and carbapenemases were investigated. mrkA expression was determined by real-time reverse transcription polymerase chain reaction. Biofilm production (25°C and 37°C, with and without humidity) was determined by the crystal violet assay. The effect of isopropanol, povidone-iodine, sodium hypochlorite, chlorhexidine digluconate, benzalkonium chloride, ethanol and triclosan on biofilm was determined. The effect of povidone-iodine on biofilm biomass and thickness was also determined by confocal laser scanning microscopy.

RESULTS: mrkA expression ranged from 28.2 to 1.3 [high or intermediate level; 64% of high-risk (HR) clones] and from 21.5 to 1.3 (50% of non-HR clones). At 25°C, biofilm formation was observed in 41% of isolates (absence of humidity) and 35% of isolates (presence of humidity), whereas at 37°C, biofilm formation was observed in 76% of isolates with and without humidity. At 25°C, biofilm producers were more frequently observed in HR clones (45% with humidity and 55% without humidity) than non-HR clones (17% with and without humidity). Biofilm viability from day 21 was higher at 25°C than 37°C. The greatest decrease in biofilm formation was observed with povidone-iodine (29% decrease), which also decreased biofilm thickness.

CONCLUSIONS: Biofilm formation in carbapenemase-producing K. pneumoniae is related to mrkA expression. Biofilm formation is affected by temperature (37°C>25°C), whereas humidity has little effect. Biofilm viability is affected by temperature (25°C>37°C). At 25°C, HR clones are more frequently biofilm producers than non-HR clones. Povidone-iodine can decrease biofilm production and biofilm thickness.}, } @article {pmid35993746, year = {2022}, author = {Do, E and Cravener, MV and Huang, MY and May, G and McManus, CJ and Mitchell, AP}, title = {Collaboration between Antagonistic Cell Type Regulators Governs Natural Variation in the Candida albicans Biofilm and Hyphal Gene Expression Network.}, journal = {mBio}, volume = {13}, number = {5}, pages = {e0193722}, pmid = {35993746}, issn = {2150-7511}, support = {R01 AI146103/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; *Candida albicans/metabolism ; *Fungal Proteins/genetics/metabolism ; Gene Expression ; Gene Expression Regulation, Fungal ; RNA ; Transcription Factors/genetics/metabolism ; }, abstract = {Candida albicans is among the most significant human fungal pathogens. However, the vast majority of C. albicans studies have focused on a single clinical isolate and its marked derivatives. We investigated natural variation among clinical C. albicans isolates in gene regulatory control of biofilm formation, a process crucial to virulence. The transcription factor Efg1 is required for biofilm-associated gene expression and biofilm formation. Previously, we found extensive variation in Efg1-responsive gene expression among 5 diverse clinical isolates. However, chromatin immunoprecipitation sequencing analysis showed that Efg1 binding to genomic loci was uniform among the isolates. Functional dissection of strain differences identified three transcription factors, Brg1, Tec1, and Wor1, for which small changes in expression levels reshaped the Efg1 regulatory network. Brg1 and Tec1 are known biofilm activators, and their role in Efg1 network variation may be expected. However, Wor1 is a known repressor of EFG1 expression and an inhibitor of biofilm formation. In contrast, we found that a modest increase in WOR1 RNA levels, reflecting the expression differences between C. albicans strains, could augment biofilm formation and expression of biofilm-related genes. The analysis of natural variation here reveals a novel function for a well-characterized gene and illustrates that strain diversity offers a unique resource for elucidation of network interactions. IMPORTANCE Clinical isolates of all pathogens vary in the strength of traits linked to disease. In this study, we focused on variation in a pathogenicity trait of the fungal pathogen Candida albicans, biofilm formation. This trait is under the control of the cell type regulator Efg1. Expression of Efg1 is known from previous studies to be repressed by a second cell type regulator, Wor1. However, we found that natural variation in biofilm formation and biofilm-related gene expression was driven by collaboration between Efg1 and Wor1. Our findings show that analysis of natural isolates can reveal unexpected features of gene function, even for well-studied genes.}, } @article {pmid35993642, year = {2022}, author = {Qamar, Z and Abdul, NS and Khan, TA and Zeeshan, T and Helal Uddin, ABM and Albaqawi, AH and Almejlad, NK}, title = {The effect of selected commercially available mouth-rinses vs. curcumin photosensitizers in an artificial mouth model mimicking their use before meals on early colonizers single species biofilm.}, journal = {European review for medical and pharmacological sciences}, volume = {26}, number = {15}, pages = {5466-5475}, doi = {10.26355/eurrev_202208_29415}, pmid = {35993642}, issn = {2284-0729}, mesh = {*Anti-Infective Agents, Local/pharmacology ; Bacteria ; Biofilms ; *Curcumin/pharmacology ; Meals ; Mouth ; Mouthwashes/pharmacology ; *Oils, Volatile/pharmacology ; Photosensitizing Agents/pharmacology ; }, abstract = {OBJECTIVE: The aim of the study was to determine the bacterial-adherence to the experimental pellicle pretreated with commercially available oral-rinse/ photosensitizer (mimicking use of oral-rinse/ photosensitizer before meals).

MATERIALS AND METHODS: An artificial mouth (NAM) system was used for the development of single-species biofilm (Actinomyces viscosus, Streptococcus mitis and Streptococcus sanguinis respectively). Two commercially available oral-rinses containing active ingredients [Essential oils (EO) and Chlorhexidine gluconate (CHX) were used. Curcumin photosensitizer (PS) was used as a photosensitizer against the microbes. For the adherence study, the experimental pellicle on the beads (in the capillary tubes of the NAM system) was pretreated with the oral-rinse and photosensitizer before the inoculation of bacteria; this would resemble the use of rinse/ photosensitizer before meal. The bacterial population of the biofilm was determined using serial dilution assay and expressed as colony forming unit per ml. Deionized distilled water was used in place of oral-rinse/photosensitizer and served as a negative-control. For the qualitative study, bacterial population viewing was carried out using Scanning Electron Microscope (SEM).

RESULTS: It was observed that on treatment with the oral-rinses the bacterial population of S.mitis, S.sanguinis and A.viscosus (adherence) was significantly reduced where the reduction was less for EO-based oral-rinse compared with that of CHX and curcumin PS in the following sequence EO
CONCLUSIONS: From the results, it appears that curcumin photosensitizer and oral-rinses contain CHX to be preferably used before-meal and EO after-meal.}, } @article {pmid35992661, year = {2022}, author = {Zhou, J and Meng, X and Han, Q and Huang, Y and Huo, L and Lei, Y}, title = {An in vitro study on the degradation of multispecies biofilm of periodontitis-related microorganisms by bovine trypsin.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {951291}, pmid = {35992661}, issn = {1664-302X}, abstract = {To investigate the degradation effect of bovine trypsin on multispecies biofilm of periodontitis-related bacteria and to provide an experimental reference for exploring new methods for controlling biofilms of periodontitis-related microorganisms, the multispecies biofilm of periodontitis-related microorganisms was established. Standard strains of Porphyromonas gingivalis, Fusobacterium nucleatum subsp. polymorpha, Actinomyces viscosus, and Aggregatibacter actinomycetemcomitans were co-cultured to form the biofilm. The experimental groups were treated with bovine trypsin, distilled water was applied as the blank control group, and phosphate saline buffer (pH = 7.4) as the negative control group. Morphological observation and quantitative analysis of extracellular polymeric substances (EPS), live bacteria, and dead bacteria were conducted using a laser confocal microscope. The morphological changes of EPS and bacteria were also observed using a scanning electron microscope. The results of morphological observations of modeling were as follows. EPS aggregated as agglomerates, and bacteria flora were wrapped by them, showing a three-dimensional network structure, and channel-like structures were inside the biofilm. Live bacteria were distributed on the surface of the EPS or embedded in them, dead bacteria aggregated between live flora and the bottom layer of biofilms. After being treated with bovine trypsin, the three-dimensional network structure and the channel-like structure disappeared, and the EPS and live and dead bacteria decreased. Quantitative analysis results are as follows. When biofilm was treated for 30 s, 1 min, and 3 min, the minimum effective concentrations of bovine trypsin to reduce EPS were 2 mg/ml (P < 0.05), 0.5 mg/ml (P < 0.05), and 0.25 mg/ml (P < 0.05), respectively. The minimum effective concentrations of bovine trypsin to reduce the live or dead bacteria were 2 mg/ml (P < 0.05), 0.5 mg/ml (P < 0.05), and 0.5 mg/ml (P < 0.05), respectively. There was no significant difference in the ratio of live/dead bacteria after the biofilm was treated for 30 s with bovine trypsin at the concentration of 0.25, 0.5, 1, and 2 mg/ml (P > 0.05), and the minimum effective concentration to reduce the ratio of live bacteria/dead bacteria was 0.25 mg/ml (P < 0.05) after treatment for 1 min and 3 min. Therefore, bovine trypsin can destroy biofilm structure, disperse biofilm and bacteria flora, and reduce the EPS and bacterial biomass, which are positively correlated with the application time and concentration.}, } @article {pmid35992652, year = {2022}, author = {Turner, AB and Gerner, E and Firdaus, R and Echeverz, M and Werthén, M and Thomsen, P and Almqvist, S and Trobos, M}, title = {Role of sodium salicylate in Staphylococcus aureus quorum sensing, virulence, biofilm formation and antimicrobial susceptibility.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {931839}, pmid = {35992652}, issn = {1664-302X}, abstract = {The widespread threat of antibiotic resistance requires new treatment options. Disrupting bacterial communication, quorum sensing (QS), has the potential to reduce pathogenesis by decreasing bacterial virulence. The aim of this study was to investigate the influence of sodium salicylate (NaSa) on Staphylococcus aureus QS, virulence production and biofilm formation. In S. aureus ATCC 25923 (agr III), with or without serum, NaSa (10 mM) downregulated the agr QS system and decreased the secretion levels of alpha-hemolysin, staphopain A and delta-hemolysin. Inhibition of agr expression caused a downregulation of delta-hemolysin, decreasing biofilm dispersal and increasing biofilm formation on polystyrene and titanium under static conditions. In contrast, NaSa did not increase biofilm biomass under flow but caused one log10 reduction in biofilm viability on polystyrene pegs, resulting in biofilms being twice as susceptible to rifampicin. A concentration-dependent effect of NaSa was further observed, where high concentrations (10 mM) decreased agr expression, while low concentrations (≤0.1 mM) increased agr expression. In S. aureus 8325-4 (agr I), a high concentration of NaSa (10 mM) decreased hla expression, and a low concentration of NaSa (≤1 mM) increased rnaIII and hla expression. The activity of NaSa on biofilm formation was dependent on agr type and material surface. Eight clinical strains isolated from prosthetic joint infection (PJI) or wound infection belonging to each of the four agr types were evaluated. The four PJI S. aureus strains did not change their biofilm phenotype with NaSa on the clinically relevant titanium surface. Half of the wound strains (agr III and IV) did not change the biofilm phenotype in the 3D collagen wound model. In addition, compared to the control, ATCC 25923 biofilms formed with 10 mM NaSa in the collagen model were more susceptible to silver. It is concluded that NaSa can inhibit QS in S. aureus, decreasing the levels of toxin production with certain modulation of biofilm formation. The effect on biofilm formation was dependent on the strain and material surface. It is suggested that the observed NaSa inhibition of bacterial communication is a potential alternative or adjuvant to traditional antibiotics.}, } @article {pmid35992170, year = {2022}, author = {LuTheryn, G and Hind, C and Campbell, C and Crowther, A and Wu, Q and Keller, SB and Glynne-Jones, P and Sutton, JM and Webb, JS and Gray, M and Wilks, SA and Stride, E and Carugo, D}, title = {Bactericidal and anti-biofilm effects of uncharged and cationic ultrasound-responsive nitric oxide microbubbles on Pseudomonas aeruginosa biofilms.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {956808}, pmid = {35992170}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cations/pharmacology ; Microbubbles ; *Nitric Oxide/metabolism/pharmacology ; *Pseudomonas aeruginosa ; }, abstract = {Bacterial biofilms are a major and ongoing concern for public health, featuring both inherited genetic resistance traits and a conferred innate tolerance to traditional antibiotic therapies. Consequently, there is a growing need for novel methods of drug delivery, to increase the efficacy of antimicrobial agents. This research evaluated the anti-biofilm and bactericidal effects of ultrasound responsive gas-microbubbles (MBs) of either air or nitric oxide, using an in vitro Pseudomonas aeruginosa biofilm model grown in artificial wound medium. The four lipid-based MB formulations evaluated were room-air MBs (RAMBs) and nitric oxide MBs (NOMBs) with no electrical charge, as well as cationic (+) RAMBs[+] and NOMBs[+]. Two principal treatment conditions were used: i) ultrasound stimulated MBs only, and ii) ultrasound stimulated MBs with a sub-inhibitory concentration (4 µg/mL) of the antibiotic gentamicin. The total treatment time was divided into a 60 second passive MB interaction period prior to 40 second ultrasound exposure; each MB formulation was tested in triplicate. Ultrasound stimulated RAMBs and NOMBs without antibiotic achieved reductions in biofilm biomass of 93.3% and 94.0%, respectively. Their bactericidal efficacy however was limited, with a reduction in culturable cells of 26.9% and 65.3%, respectively. NOMBs with sub-inhibitory antibiotic produced the most significant reduction in biofilm biomass, corresponding to a 99.9% (SD ± 5.21%); and a 99.9% (SD ± 0.07%) (3-log) reduction in culturable bacterial cells. Cationic MBs were initially manufactured to promote binding of MBs to negatively charged biofilms, but these formulations also demonstrated intrinsic bactericidal properties. In the absence of antibiotic, the bactericidal efficacy of RAMB[+] and NOMB[+] was greater that of uncharged counterparts, reducing culturable cells by 84.7% and 86.1% respectively; increasing to 99.8% when combined with antibiotic. This study thus demonstrates the anti-biofilm and bactericidal utility of ultrasound stimulated MBs, and specifically is the first to demonstrate the efficacy of a NOMB for the dispersal and potentiation of antibiotics against bacterial biofilms in vitro. Importantly the biofilm system and complex growth-medium were selected to recapitulate key morphological features of in vivo biofilms. The results us offer new insight for the development of new clinical treatments, for example, in chronic wounds.}, } @article {pmid35989296, year = {2022}, author = {Escamilla-Gómez, G and Sánchez-Vargas, O and Escobar-García, DM and Pozos-Guillén, A and Zavala-Alonso, NV and Gutiérrez-Sánchez, M and Pérez-López, JE and Sánchez-Balderas, G and Romo-Ramírez, GF and Ortiz-Magdaleno, M}, title = {Surface degradation and biofilm formation on hybrid and nanohybrid composites after immersion in different liquids.}, journal = {Journal of oral science}, volume = {64}, number = {4}, pages = {263-270}, doi = {10.2334/josnusd.22-0085}, pmid = {35989296}, issn = {1880-4926}, mesh = {Biofilms ; *Composite Resins ; Dental Materials ; *Immersion ; Materials Testing ; Saliva, Artificial ; Streptococcus mutans ; Surface Properties ; Water ; }, abstract = {PURPOSE: This study evaluated the association of surface degradation and formation of Streptococcus mutans (S. mutans) biofilm in resin-based composites (RBCs) after storage in different acidic liquids.

METHODS: To evaluate microhardness and surface micromorphology, hybrid and nanohybrid RBC discs were stored in artificial gastric acid, cola drink, orange juice, artificial saliva, and distilled water for three intervals of 15 min per day for 7, 15, and 30 days. After 30 days of storage, surface roughness was analyzed, and the RBC discs were placed in a biofilm reactor inoculated with S. mutans to evaluate surface biofilm formation.

RESULTS: As compared with nanohybrid RBCs, roughness and surface microhardness values were significantly lower (P < 0.05) for hybrid RBCs stored in artificial gastric acid, followed by specimens stored in cola drink and orange juice. Artificial gastric acid caused greater surface degradation, which increased the biomass of S. mutans on the surface of both RBC types.

CONCLUSION: Surface degradation of hybrid and nanohybrid RBCs correlated with the pH of the liquid, while S. mutans biofilm formation was associated with increased surface roughness in hybrid RBCs.}, } @article {pmid35985586, year = {2022}, author = {Aboulela, A and Peyre Lavigne, M and Pons, T and Bounouba, M and Schiettekatte, M and Lepercq, P and Mercade, M and Patapy, C and Meulenyzer, S and Bertron, A}, title = {The fate of tetrathionate during the development of a biofilm in biogenic sulfuric acid attack on different cementitious materials.}, journal = {The Science of the total environment}, volume = {850}, number = {}, pages = {158031}, doi = {10.1016/j.scitotenv.2022.158031}, pmid = {35985586}, issn = {1879-1026}, mesh = {Alkalies ; Biofilms ; Oxidation-Reduction ; Sulfates/metabolism ; *Sulfur/metabolism ; Sulfur Compounds ; Sulfuric Acids ; *Thiosulfates ; }, abstract = {The biodeterioration of cement-based materials in sewer environments occurs because of the production of sulfuric acid from the biochemical oxidation of H2S by sulfur-oxidizing bacteria (SOB). In the perspective of determining the possible reaction pathways for the sulfur cycle in such conditions, hydrated cementitious binders were exposed to an accelerated laboratory test (BAC test) to reproduce a biochemical attack similar to the one occurring in the sewer networks. Tetrathionate was used as a reduced sulfur source to naturally develop sulfur-oxidizing activities on the surfaces of materials. The transformation of tetrathionate was investigated on materials made from different binders: Portland cement, calcium aluminate cement, calcium sulfoaluminate cement and alkali-activated slag. The pH and the concentration of the different sulfur species were monitored in the leached solutions during 3 months of exposure. The results showed that the formation of different polythionates was independent of the nature of the material. The main parameter controlling the phenomena was the evolution of the pH of the leached solutions. Moreover, tetrathionate disproportionation was detected with the formation of more reduced forms of sulfur compounds (pentathionate, hexathionate and elemental sulfur) along with thiosulfate and sulfate. The experimental findings allowed numerical models to be developed to estimate the amount of sulfur compounds as a function of the pH evolution. In addition, biomass samples were collected from the exposed surface and from the deteriorated layers to identify the microbial populations. No clear influence of the cementitious materials on the selected populations was detected, confirming the previous results concerning the impact of the materials on the selected reaction pathways for tetrathionate transformation.}, } @article {pmid35985488, year = {2022}, author = {Fuentes, E and Pérez-Velón, D and Prieto, B}, title = {Effects of changes in UV-B radiation levels on biofilm-forming organisms commonly found in cultural heritage surfaces.}, journal = {Environmental research}, volume = {214}, number = {Pt 4}, pages = {114061}, doi = {10.1016/j.envres.2022.114061}, pmid = {35985488}, issn = {1096-0953}, mesh = {Biofilms ; Climate Change ; *Ozone ; Plants ; *Ultraviolet Rays ; }, abstract = {Accurate measuring and monitoring methods available since the 1980s have shown that the amount of Ultraviolet B (UV-B) radiation reaching the Earth's surface has increased as a result of degradation of the ozone layer. Since the adoption of the Montreal Protocol in 1987, ozone levels have been recovering successfully. However, in the context of the current climate change, other factors such as changes in cloud patterns and an increased incidence of natural disasters (e.g. fires) may be disrupting this recovery. The present study aimed to investigate the effects of different UV-B radiation levels on biofilms colonising heritage monuments. For this purpose, the effects of current UV-B levels on a biofilm composed of Synechocystis sp. (a cyanobacterium), Bracteacoccus minor (a green alga) and Fusarium sp. (a fungus) were compared at three points along a South-North transect: Portugal, Galicia (NW Spain) and Ireland (from highest to lowest UV-B radiation, respectively). Increased levels of UV-B radiation caused changes in the growth, physiological state and composition of subaerial biofilms, with cyanobacteria being more resistant than green algae to high levels of UV-B. A reduction of fungal growth and extracellular polymer substances (EPS) production was also observed, related to the reduction of biofilm aggregation at high UV-B levels.}, } @article {pmid35981676, year = {2022}, author = {Krishnamoorthi, R and Srinivash, M and Mahalingam, PU and Malaikozhundan, B and Suganya, P and Gurushankar, K}, title = {Antimicrobial, anti-biofilm, antioxidant and cytotoxic effects of bacteriocin by Lactococcus lactis strain CH3 isolated from fermented dairy products-An in vitro and in silico approach.}, journal = {International journal of biological macromolecules}, volume = {220}, number = {}, pages = {291-306}, doi = {10.1016/j.ijbiomac.2022.08.087}, pmid = {35981676}, issn = {1879-0003}, mesh = {Amino Acids/metabolism ; Ammonium Sulfate/metabolism ; Anti-Bacterial Agents/chemistry ; Antioxidants/metabolism/pharmacology ; *Bacteriocins/chemistry ; *Cultured Milk Products ; Detergents ; Humans ; *Lactococcus lactis/metabolism ; Peptide Hydrolases/metabolism ; Solvents/metabolism ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {The current study aimed to screen bacteriocin producing LAB from different dairy products and evaluation of their biological properties. Initially, 12 (4-chess, 4-curd, and 4-yohurt) LAB species were isolated and only 4 isolates alone were selected based on their clear yellow halo zone around the colonies in the selective medium. The selected 4 isolates were identified based on their morphological and biochemical characteristics. Among them, the strain CH3 have showed better antimicrobial effects on selected human pathogens. The isolated strain CH3 were further identified as Lactococcus lactis strain CH3 (MZ636710) by SEM imaging and 16 s rRNA molecular sequencing. Bacteriocin was extracted from L. lactis strain CH3 and partially purified using 60 % ammonium sulphate and then completely purified by G-50 column chromatography. The purified bacteriocin showed a specific activity of 5859.37 AU/mg in 24.7 % of recovery and 10.9-fold purification. The molecular weight of bacteriocin was 3.5 kDa as observed in SDS-PAGE. The bacteriocin showed sensitivity to proteolytic enzymes and resistance to high temperature, wide range of pH, organic solvents and detergents. FT-IR spectral studies of bacteriocin detected the existence of OH/NH-stretching, CH, and COC and CO bonds. NMR spectrum showed one doublet and 4 various singlet peaks at different ppm, indicating the occurrence of six amino acids in the structure of purified bacteriocin. The purified bacteriocin have shown stronger antimicrobial and anti-biofilm activity against selected human pathogens at 100 μg/mL. SEM showed the evidence of structural deformation and loss of membrane integrity of bacterial cells treated with bacteriocin. Bacteriocin exhibited greater DPPH radical scavenging potential with an EC50 value of 12.5 μg/mL. Bacteriocin have not shown significant toxicity on normal human dermal fibroblast (NHDF) cells (83.2 % at 100 μg/ mL). Furthermore, in silico studies using molecular modeling and docking were performed to know the proteins involved in antimicrobial action. The results suggests that bacteriocin could be an alternative to combat AMR pathogens and more suitable for food and dairy industries to preserve food without contamination.}, } @article {pmid35981588, year = {2022}, author = {Jing, X and Chen, S and Liu, X and Yang, Y and Rensing, C and Zhou, S}, title = {Potassium channel mediates electroactive biofilm formation via recruiting planktonic Geobacter cells.}, journal = {The Science of the total environment}, volume = {850}, number = {}, pages = {158035}, doi = {10.1016/j.scitotenv.2022.158035}, pmid = {35981588}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Geobacter/physiology ; Plankton ; Potassium ; Potassium Channels ; }, abstract = {Potassium (K[+])-channel-based electrical signaling can coordinate microbial actions at a distance that provides an evolutionary advantage to cell communities. Electroactive cells are usually cultured surrounded by an electric field which provided stronger electrical signaling than the K[+]-mediated electrical signaling. Whether the K[+] signaling also plays a role in coordinating the behavior of electroactive microorganisms has not been accurately demonstrated. Thus, we constructed a K[+]-channel-deficient strain ΔgsuK of Geobacter sulfurreducens to directly investigate roles of K[+] signaling in electroactive biofilm formation for the first time. The ΔgsuK strain exhibited significantly inferior biofilm formation (i.e., biomass, thickness and component) and consequently showed weaker electrical performance (i.e., start-up time, current output, electrochemical catalytic behavior and charge transfer resistance) than the wild-type strain. Individual electric generation capacity and the expression of genes involved in biofilm formation and electrical performance in the single cell did not significantly change with the deletion of gsuK, indicating that K[+] signaling indeed influenced the recruiting behavior of planktonic cell but not the functioning of the single cell related to biofilm formation or electric generation. This study is intended to provide an in-depth understanding of electroactive biofilm formation and serve as a basis for optimizing its electrical performance via strengthening the recruitment behavior.}, } @article {pmid35981577, year = {2022}, author = {Li, J and Ou, R and Liao, H and Ma, J and Sun, L and Jin, Q and He, D and Wang, Q}, title = {Natural lighting enhancing the algae proliferation and nitrogen removal in membrane-aerated bacterial-algal biofilm reactor.}, journal = {The Science of the total environment}, volume = {851}, number = {Pt 1}, pages = {158063}, doi = {10.1016/j.scitotenv.2022.158063}, pmid = {35981577}, issn = {1879-1026}, mesh = {Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; Cell Proliferation ; Chlorophyll ; Denitrification ; *Environmental Pollutants ; Lighting ; *Nitrogen/metabolism ; Waste Disposal, Fluid/methods ; Wastewater ; }, abstract = {Membrane-aerated bacterial-algal biofilm reactor (MABAR) is an emerging and novel technology in recent years, which has been attracting increasing attention due to its cost-effectiveness and superior removal performance of pollutants by versatile removal pathways in symbiotic bacterial-algal biofilm. However, the wider application of MABAR is hindered by the dilemma of insufficient algae biomass. In this study, an MABAR under natural sunlight was developed and operated for 160 d to access the feasibility of enhancing algae proliferation by natural lighting. Results showed that the MABAR with natural sunlight (nMABAR) demonstrated better performance of pollutants removal. High removal efficiencies of organic matter and NH4-N in nMABAR were 90 % and 92 %, respectively. In particular, the removal efficiency of TN in nMABAR, under less aeration, was up to 80 %, which was 15 % higher than the control reactor. The Chlorophyll-a content indicated that natural sunlight facilitated to algae growth in MABAR, and algae assimilation might be the dominant contributor to NH4-N removal. Moreover, there were microbial shifts in bacterial-algal biofilm in a response to the natural lighting, the nMABAR uniquely possessed a bacterial phylotype termed Thiocapsa, which could play an important role in bacterial nitrification. Algal phylotype Chlorophyceae significantly contributed to pollutants removal and synergistic relationship with bacteria. In addition, the superb performance of nMABAR under less aeration condition suggested that abundant algae were capable of supplying enough O2 for the system. These results provided insight into the natural lighting on algae-bacteria synergistic growth and cost-effective operation strategy for MABAR.}, } @article {pmid35981515, year = {2022}, author = {Exterkate, RAM and Brandt, BW and Crielaard, W}, title = {Effects of Surface Prereacted Glass on Saliva-Derived Polymicrobial Biofilms in an Active Attachment Biofilm Model.}, journal = {Caries research}, volume = {56}, number = {3}, pages = {215-225}, pmid = {35981515}, issn = {1421-976X}, mesh = {Humans ; *Saliva ; *Biofilms ; Fluorides/pharmacology ; Dental Materials/pharmacology ; Lactic Acid ; }, abstract = {Bioactive restorative materials are being developed to either influence the de/remineralization balance of the dental hard tissues locally or to release components that interact with the oral microbiota. Surface prereacted glass (S-PRG, Shofu, Japan) is a material that may influence both processes. S-PRG releases fluoride, which can interact with the de/remineralization process, and a range of other compounds that may influence the oral microbiota. In the current study, several experiments were performed to investigate the potential of S-PRG to influence both the growth and lactic acid production of saliva-derived polymicrobial biofilms. Biofilm formation was studied using the Amsterdam Active Attachment model. An eluate of the S-PRG particles was tested by adding it to the growth medium or by exposing the biofilms to it for 1 h. The effect of S-PRG particles was tested by adding the particles to the growth medium. The current experiments showed that the presence of S-PRG eluate in the medium influenced biofilm growth and lactic acid production even at low concentrations. The composition of the biofilms changed in the presence of S-PRG eluate, even at concentrations of S-PRG eluate at which biofilm viability was not affected. Treatment of developing biofilms with S-PRG eluate did neither show an effect on biofilm viability nor on lactic acid production. The addition of S-PRG particles to the growth medium resulted in both a lower biofilm viability and lower lactic acid production, indicating that the release of ions from the particles was fast enough to influence biofilm formation. From the current experiments, it can be concluded that S-PRG has the potential to influence biofilm growth, but the presence of the released ions during biofilm formation is required to show an effect.}, } @article {pmid35980199, year = {2022}, author = {Yin, W and Zhang, Z and Shuai, X and Zhou, X and Yin, D}, title = {Caffeic Acid Phenethyl Ester (CAPE) Inhibits Cross-Kingdom Biofilm Formation of Streptococcus mutans and Candida albicans.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0157822}, pmid = {35980199}, issn = {2165-0497}, mesh = {Humans ; Streptococcus mutans ; Candida albicans ; Gentian Violet/pharmacology ; Sincalide/pharmacology ; *Dental Caries/prevention & control ; Biofilms ; *Anti-Infective Agents/pharmacology ; Polysaccharides ; *Biological Products ; Anthracenes/pharmacology ; }, abstract = {Streptococcus mutans and Candida albicans exhibit strong cariogenicity through cross-kingdom biofilm formation during the pathogenesis of dental caries. Caffeic acid phenethyl ester (CAPE), a natural compound, has potential antimicrobial effects on each species individually, but there are no reports of its effect on this dual-species biofilm. This study aimed to explore the effects of CAPE on cariogenic biofilm formation by S. mutans and C. albicans and the related mechanisms. The effect of CAPE on planktonic cell growth was investigated, and crystal violet staining, the anthrone-sulfuric acid assay and confocal laser scanning microscopy were used to evaluate biofilm formation. The structures of the formed biofilms were observed using scanning electron microscopy. To explain the antimicrobial effect of CAPE, quantitative real-time PCR (qRT-PCR) was applied to monitor the relative expression levels of cariogenic genes. Finally, the biocompatibility of CAPE in human oral keratinocytes (HOKs) was evaluated using the CCK-8 assay. The results showed that CAPE suppressed the growth, biofilm formation and extracellular polysaccharides (EPS) synthesis of C. albicans and S. mutans in the coculture system of the two species. The expression of the gtf gene was also suppressed by CAPE. The efficacy of CAPE was concentration dependent, and the compound exhibited acceptable biocompatibility. Our research lays the foundation for further study of the application of the natural compound CAPE as a potential antimicrobial agent to control dental caries-associated cross-kingdom biofilms. IMPORTANCE Severe dental caries is a multimicrobial infectious disease that is strongly induced by the cross-kingdom biofilm formed by S. mutans and C. albicans. This study aimed to investigate the potential of caffeic acid phenethyl ester (CAPE) as a natural product in the prevention of severe caries. This study clarified the inhibitory effect of CAPE on cariogenic biofilm formation and the control of cariogenic genes. It deepens our understanding of the synergistic cariogenic effect of S. mutans and C. albicans and provides a new perspective for the prevention and control of dental caries with CAPE. These findings may contribute to the development of CAPE as a promising antimicrobial agent targeting this caries-related cross-kingdom biofilm.}, } @article {pmid35980045, year = {2022}, author = {Jabbour, N and Morello, E and Camiade, E and Lartigue, MF}, title = {Biofilm Formation in Streptococcus agalactiae Is Inhibited by a Small Regulatory RNA Regulated by the Two-Component System CiaRH.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0063522}, pmid = {35980045}, issn = {2165-0497}, mesh = {Animals ; Infant, Newborn ; Humans ; *Streptococcus agalactiae/genetics ; *Gene Expression Regulation, Bacterial ; RNA ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Glucans ; Nucleotides ; RNA, Messenger ; Glycogen/metabolism ; Glucose ; Carbon/metabolism ; }, abstract = {Regulatory small RNAs (sRNAs) are involved in the adaptation of bacteria to their environment. CiaR-dependent sRNAs (csRNAs) are controlled by the regulatory two-component system (TCS) CiaRH, which is widely conserved in streptococci. Except for Streptococcus pneumoniae and Streptococcus sanguinis, the targets of these csRNAs have not yet been investigated. Streptococcus agalactiae, the leading cause of neonatal infections, has four conserved csRNA genes, namely, srn015, srn024, srn070, and srn085. Here, we demonstrate the importance of the direct repeat TTTAAG-N5-TTTAAG in the regulation of these csRNAs by CiaRH. A 24-nucleotide Srn024-sap RNA base-pairing region is predicted in silico. The sap gene encodes a LPXTG-cell wall-anchored pullulanase. This protein cleaves α-glucan polysaccharides such as pullulan and glycogen present in the environment to release glucose and is involved in adhesion to human cervical epithelial cells. Inactivation of S. agalactiae pullulanase (SAP) leads to no bacterial growth in a medium with only pullulan as a carbon source and reduced biofilm formation, while deletion of ciaRH and srn024 genes significantly increases bacterial growth and biofilm formation. Using a new translational fusion vector, we demonstrated that Srn024 is involved in the posttranscriptional regulation of sap expression. Complementary base pair exchanges in S. agalactiae suggest that Srn024 interacts directly with sap mRNA and that disruption of this RNA pairing is sufficient to yield the biofilm phenotype of Srn024 deletion. These results suggest the involvement of Srn024 in the adaptation of S. agalactiae to environmental changes and biofilm formation, likely through the regulation of the sap gene. IMPORTANCE Although Streptococcus agalactiae is a commensal bacterium of the human digestive and genitourinary tracts, it is also an opportunistic pathogen for humans and other animals. As the main cause of neonatal infections, it is responsible for pneumonia, bacteremia, and meningitis. However, its adaptation to these different ecological niches is not fully understood. Bacterial regulatory networks are involved in this adaptation, and the regulatory TCSs (e.g., CiaRH), as well as the regulatory sRNAs, are part of it. This study is the first step to understand the role of csRNAs in the adaptation of S. agalactiae. This bacterium does not currently exhibit extensive antibiotic resistance. However, it is crucial to find alternatives before multidrug resistance emerges. Therefore, we propose that drugs targeting regulatory RNAs with Srn024-like activities would affect pathogens by reducing their abilities to form biofilm and to adapt to host niches.}, } @article {pmid35979499, year = {2022}, author = {Radzieta, M and Malone, M and Ahmad, M and Dickson, HG and Schwarzer, S and Jensen, SO and Lavery, LA}, title = {Metatranscriptome sequencing identifies Escherichia are major contributors to pathogenic functions and biofilm formation in diabetes related foot osteomyelitis.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {956332}, pmid = {35979499}, issn = {1664-302X}, abstract = {Osteomyelitis in the feet of persons with diabetes is clinically challenging and is associated with high rates of amputation. In this study RNA-sequencing was employed to explore microbial metatranscriptomes with a view to understand the relative activity and functions of the pathogen/s responsible for diabetes foot osteomyelitis (DFO). We obtained 25 intraoperative bone specimens from persons with confirmed DFO, observing that Escherichia spp. (7%), Streptomyces spp. (7%), Staphylococcus spp. (6%), Klebsiella spp. (5%) and Proteus spp. (5%) are the most active taxa on average. Data was then subset to examine functions associated with pathogenesis (virulence and toxins), biofilm formation and antimicrobial/multi-drug resistance. Analysis revealed Escherichia spp. are the most active taxa relative to pathogenic functions with K06218 (mRNA interferase relE), K03699 (membrane damaging toxin tlyC) and K03980 (putative peptidoglycan lipid II flippase murJ), K01114 (membrane damaging toxin plc) and K19168 (toxin cptA) being the most prevalent pathogenic associated transcripts. The most abundant transcripts associated with biofilm pathways included components of the biofilm EPS matrix including glycogen synthesis, cellulose synthesis, colonic acid synthesis and flagella synthesis. We further observed enrichment of a key enzyme involved in the biosynthesis of L-rhamnose (K01710 -dTDP-glucose 4,6-dehydratase rfbB, rmlB, rffG) which was present in all but four patients with DFO.}, } @article {pmid35979211, year = {2022}, author = {Devanga Ragupathi, NK and Veeraraghavan, B and Karunakaran, E and Monk, PN}, title = {Editorial: Biofilm-mediated nosocomial infections and its association with antimicrobial resistance: Detection, prevention, and management.}, journal = {Frontiers in medicine}, volume = {9}, number = {}, pages = {987011}, pmid = {35979211}, issn = {2296-858X}, } @article {pmid35978046, year = {2022}, author = {Mirzaei, A and Nasr Esfahani, B and Ghanadian, M and Moghim, S}, title = {Alhagi maurorum extract modulates quorum sensing genes and biofilm formation in Proteus mirabilis.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {13992}, pmid = {35978046}, issn = {2045-2322}, mesh = {Agar ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; *Biofilms/drug effects/growth & development ; Catheters/adverse effects/microbiology ; *Fabaceae/chemistry ; Humans ; Phytotherapy ; *Plant Extracts/pharmacology ; *Plants, Medicinal/chemistry ; *Proteus mirabilis/drug effects/genetics/pathogenicity/physiology ; *Quorum Sensing/drug effects/genetics ; Urinary Tract Infections/microbiology ; Virulence/drug effects/genetics ; }, abstract = {Proteus mirabilis (P. mirabilis) is a frequent cause of catheter-associated urinary tract infections. This study aims to investigate the anti-infective effect of Alhagi maurorum extract (AME), the traditional medicinal plant in the middle east, on the biofilm-forming P. mirabilis isolates. Hydroalcoholic extract and oil of A. maurorum were characterized by HPLC and GC-MS. The antiproliferative, anti-biofilm, and bactericidal activity of AME at various concentrations were assessed by turbidity, crystal violet binding, and agar well diffusion assays, respectively. The AME's effect on adhesion and quorum sensing (QS) were investigated by in vitro adhesion assay on cell culture and agar overlay assay using Janthinobacterium lividum (ATCC 12472) as a biosensor strain. In addition, the expression level of selected genes involved in QS and biofilm regulation were determined by quantitative Real-Time PCR. Furthermore, the bladder phantom model was created to evaluate the assays and investigate the catheter's calcium deposition. The most effective chemical compounds found in AME were tamarixetin, quercetin, and trans-anethole. Although AME did not inhibit swarming motility, it reduced biofilm production and exerted a concentration-dependent anti-adhesive and anti-QS activity against P. mirabilis. AME also downregulated the expression level of selected genes involved in biofilm formation and QS. This study showed that AME as a natural compound reduced biofilm formation of P. mirabilis by targeting virulence factor genes, quorum sensing, and other strategies that include preventing the adhesion of P. mirabilis to the cells. The results suggest that A. maurorum extract might have the potential to be considered for preventing UTIs caused by P. mirabilis.}, } @article {pmid35977081, year = {2022}, author = {Meesaragandla, B and Hayet, S and Fine, T and Janke, U and Chai, L and Delcea, M}, title = {Inhibitory Effect of Epigallocatechin Gallate-Silver Nanoparticles and Their Lysozyme Bioconjugates on Biofilm Formation and Cytotoxicity.}, journal = {ACS applied bio materials}, volume = {5}, number = {9}, pages = {4213-4221}, pmid = {35977081}, issn = {2576-6422}, abstract = {Biofilms are multicellular communities of microbial cells that grow on natural and synthetic surfaces. They have become the major cause for hospital-acquired infections because once they form, they are very difficult to eradicate. Nanotechnology offers means to fight biofilm-associated infections. Here, we report on the synthesis of silver nanoparticles (AgNPs) with the antibacterial ligand epigallocatechin gallate (EGCG) and the formation of a lysozyme protein corona on AgNPs, as shown by UV-vis, dynamic light scattering, and circular dichroism analyses. We further tested the activity of EGCG-AgNPs and their lysozyme bioconjugates on the viability of Bacillus subtilis cells and biofilm formation. Our results showed that, although EGCG-AgNPs presented no antibacterial activity on planktonic B. subtilis cells, they inhibited B. subtilis biofilm formation at concentrations larger than 40 nM, and EGCG-AgNP-lysozyme bioconjugates inhibited biofilms at concentrations above 80 nM. Cytotoxicity assays performed with human cells showed a reverse trend, where EGCG-AgNPs barely affected human cell viability while EGCG-AgNP-lysozyme bioconjugates severely hampered viability. Our results therefore demonstrate that EGCG-AgNPs may be used as noncytotoxic antibiofilm agents.}, } @article {pmid35976734, year = {2022}, author = {Wongsuk, T and Boonsilp, S and Pumeesat, P and Homkaew, A and Sangsri, T and Chongtrakool, P}, title = {Genotyping, antifungal susceptibility testing, and biofilm formation of Trichosporon spp. isolated from urine samples in a University Hospital in Bangkok, Thailand.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {69}, number = {3}, pages = {247-257}, doi = {10.1556/030.2022.01797}, pmid = {35976734}, issn = {1588-2640}, mesh = {Humans ; Antifungal Agents/pharmacology ; *Trichosporon/genetics ; Genotype ; Thailand ; *Trichosporonosis/microbiology ; Microbial Sensitivity Tests ; Hospitals ; }, abstract = {The basidiomycetes yeast Trichosporon is widespread in the natural environment, but can cause disease, mainly in immunocompromised patients. However, there have been only few studies about this infection in Thailand. In this study, we characterized 53 Trichosporon spp. isolated from urine samples from patients admitted to a single hospital in Bangkok, Thailand over a one-year period from 2019 to 2020. The strains were identified using colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and nucleotide sequence analysis of intergenic spacer 1 (IGS1). Fifty-one isolates were Trichosporon asahii, and the remaining isolates were Trichosporon inkin and other Trichosporon species. Three genotypes of IGS1-1, 3, and 7 were observed among T. asahii. The sensitivity of the yeasts to the antifungal drugs amphotericin B, fluconazole, and voriconazole ranged from 0.25 to >16 μg ml-1, 0.5-8 μg ml-1, and 0.01-0.25 μg ml-1, respectively. We investigated biofilm formation by the isolates, and no biofilm production was found in one isolate, low biofilm production in forty-four isolates, and medium biofilm production in six isolates. T. inkin produced biofilms at low levels, and Trichosporon spp. produced biofilms at medium levels. This research increases our understanding of the molecular epidemiology of Trichosporon spp. isolated from one university hospital in Bangkok, Thailand, and reveals their genetic diversity, antifungal susceptibility profiles, and capacity for in vitro biofilm production.}, } @article {pmid35976101, year = {2022}, author = {Coaguila-Llerena, H and Ordinola-Zapata, R and Staley, C and Dietz, M and Chen, R and Faria, G}, title = {Multispecies biofilm removal by a multisonic irrigation system in mandibular molars.}, journal = {International endodontic journal}, volume = {55}, number = {11}, pages = {1252-1261}, pmid = {35976101}, issn = {1365-2591}, support = {UL1 TR002494/TR/NCATS NIH HHS/United States ; 88887.310463/2018-00//Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES), in the scope of the Program CAPES-PrInt/ ; UL1-TR002494/TR/NCATS NIH HHS/United States ; 88887.570038/2020-00//Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES), in the scope of the Program CAPES-PrInt/ ; UL1-TR002494/TR/NCATS NIH HHS/United States ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Humans ; Molar ; Root Canal Irrigants ; *Root Canal Preparation/methods ; Therapeutic Irrigation/methods ; Ultrasonics ; }, abstract = {AIM: The aim of the study was to assess biofilm removal efficacy of GentleWave System and passive ultrasonic irrigation (PUI).

METHODOLOGY: Twenty-two human mandibular molars with Vertucci's type II configuration in the mesial root were selected. Teeth were autoclaved, inoculated with dental plaque and incubated in a CDC biofilm reactor for two weeks. The mesial roots were instrumented up to 20.06 file (V-Taper) for the GentleWave group and up to 35.04 file (Vortex Blue) for PUI group. Irrigation was performed using GentleWave and PUI irrigation protocols (n = 11). Dentine debris on paper points samples were obtained for quantitative real-time polymerase chain reaction (qPCR) and 16S ribosomal RNA gene sequencing (next-generation aequencing-NGS). For qPCR, a non-parametric test (α = 0.05) was used. Next-generation sequencing data were analysed using mothur, with alpha diversity calculated as the Shannon and Chao1 indices and Bray-Curtis dissimilarities were used for beta diversity. Differences in alpha diversity and abundances of genera were evaluated using Kruskal-Wallis test. Differences in community composition were evaluated using analysis of similarity with Bonferroni correction for multiple comparisons.

RESULTS: Quantitative real-time polymerase chain reaction results showed that the reduction estimated in percentages for both groups was equivalent (p > .05). NGS analysis showed that both techniques promoted a significant reduction in reads and OTUs number (p < .05). Shannon alpha diversity and Chao1 index showed no differences between pre- or post-treatment samples for both groups (p > .05). Additionally, pre-treatment communities differed from post-treatment samples in both groups regarding bacterial taxa reduction (ANOSIM R = 0.50 and 0.55, p < .001).

CONCLUSIONS: Bacterial reduction in mesial roots of mandibular molars prepared to 35.04 with PUI was similar to those prepared to 20.06 with a multisonic irrigant activation system.}, } @article {pmid35975859, year = {2022}, author = {Sikarwar, J and Singh, J and Singh, TP and Sharma, P and Sharma, S}, title = {The Mechanism of Action of Lactoferrin - Nucleoside Diphosphate Kinase Complex in Combating Biofilm Formation.}, journal = {Protein and peptide letters}, volume = {29}, number = {10}, pages = {839-850}, doi = {10.2174/0929866529666220816160517}, pmid = {35975859}, issn = {1875-5305}, support = {I-1082//Indian Council of Medical Research (ICMR)/ ; }, mesh = {*Nucleoside-Diphosphate Kinase/chemistry/metabolism ; Lactoferrin/pharmacology ; Pseudomonas aeruginosa ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Iron ; Adenosine Diphosphate ; }, abstract = {BACKGROUND: The ESKAPE group of pathogens which comprise of multidrug resistant bacteria, namely Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species are the cause of deadly nosocomial infections all over the world. While these pathogens have developed robust strategies to resist most antibiotics, their ability to form biofilms is one of their most combative properties. Hence there is an urgent need to discover new antibacterial agents which could prevent or destroy the biofilms made by these bacteria. Though it has been established that lactoferrin (LF), a potent iron binding antibacterial, antifungal, and antiviral protein displays anti-biofilm properties, its mechanisms of action, in addition to its iron chelation property, still remains unclear.

OBJECTIVE: The binding and inhibition studies of LF with the enzyme Nucleoside diphosphate Kinase (NDK) and its elastase cleaved truncated 12 kDa fragment (12-NDK).

METHODS: The characterization studies of NDK and 12-NDK using florescence spectroscopy, dynamic light scattering, size exclusion chromatography and ADP-glo Kinase Assay. Inhibition studies of LF-NDK using ADP-glo kinase assay, Surface Plasmon Resonance and Biofilm inhibition studies.

RESULTS: NDK and 12-NDK were cloned, expressed and purified from Acinetobacter baumannii and Pseudomonas aeruginosa. The characterization studies revealed NDK and 12-NDK from both species are stable and functional. The inhibition studies of LF-NDK revealed stable binding and inhibition of kinase activity by LF.

CONCLUSION: The binding and inhibition studies have shown that while LF binds with both the NDK and their truncated forms, it tends to have a higher binding affinity with the truncated 12 kDa fragments, resulting in their decreased kinase activity. This study essentially gives a new direction to the field of inhibition of biofilm formation, as it proves that LF has a novel mechanism of action in other than iron sequestration.}, } @article {pmid35974918, year = {2022}, author = {Kim, HR and Han, MS and Eom, YB}, title = {Anti-bacterial and Anti-biofilm Effects of Equol on Yersinia enterocolitica.}, journal = {Indian journal of microbiology}, volume = {62}, number = {3}, pages = {401-410}, pmid = {35974918}, issn = {0046-8991}, abstract = {Yersinia enterocolitica has clinical significance due to its etiological role in yersiniosis and gastroenteritis. This study was designed to assess anti-bacterial and anti-biofilm effects of equol on Y. enterocolitica via phenotypic and genetic analyses. To determine its anti-bacterial activity, minimum inhibitory concentrations (MICs) of equol against clinically isolated Y. enterocolitica strains were analyzed. Subsequently, it was confirmed that the sub-MIC90 value of equol could inhibit biofilm formation and reduce preformed biofilm. Furthermore, it was found that equol could reduce the expression of biofilm-related (hmsT) gene in Y. enterocolitica. This study also demonstrated that equol not only reduced levels of bacterial motility, but also decreased the expression of a motility-related (flhDC) gene in Y. enterocolitica. XTT [2,3-bis (2-metoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction analysis revealed that equol attenuated cellular metabolic activities in Y. enterocolitica biofilm. Additionally, changes in biomass and cell density in equol-treated biofilms were visualized using a confocal laser scanning microscope. In conclusion, this study suggests that equol is a potential anti-bacterial and anti-biofilm agent to treat Y. enterocolitica.}, } @article {pmid35974372, year = {2022}, author = {Alfian, AR and Watchaputi, K and Sooklim, C and Soontorngun, N}, title = {Production of new antimicrobial palm oil-derived sophorolipids by the yeast Starmerella riodocensis sp. nov. against Candida albicans hyphal and biofilm formation.}, journal = {Microbial cell factories}, volume = {21}, number = {1}, pages = {163}, pmid = {35974372}, issn = {1475-2859}, support = {Petchra Pra Jom Klao scholarship//King Mongkut's University Technology Thonburi/ ; 64A306000038//Thailand Science Research and Innovation/ ; N42A650315//National Research Council of Thailand (NRCT) and and King Mongkut's University of Technology Thonburi for Mid-Career Researcher grant/ ; }, mesh = {Animals ; Anti-Bacterial Agents ; Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; Glycolipids ; Humans ; Oleic Acids ; Palm Oil ; *Saccharomycetales ; Surface-Active Agents/chemistry/pharmacology ; Yeasts ; }, abstract = {BACKGROUND: Microbial derived-surfactants display low eco-toxicity, diverse functionality, high biodegradability, high specificity, and stability under extreme conditions. Sophorolipids are emerging as key biosurfactants of yeast origins, used in various industrial sectors to lower surface tension. Recently, sophorolipid complexes have been applied in biomedicals and agriculture to eradicate infectious problems related to human and plant fungal pathogens. This study aimed to characterize the functional properties and antifungal activities of sophorolipids produced by a newly characterized Starmerella riodocensis GT-SL1R sp. nov. strain.

RESULTS: Starmerella riodocensis GT-SL1R sp. nov. strain was belonged to Starmerella clade with 93.12% sequence similarity using the ITS technique for strain identification. Sophorolipids production was examined, using co-carbon substrates glucose and palm oil, with a yield on the substrate between 30 and 46%. Using shake-flasks, the S. riodocensis GT-SL1R strain produced biosurfactants with an emulsification activity of 54.59% against kerosene compared to the S. bombicola BCC5426 strain with an activity of 60.22%. Maximum productivities of GT-SL1R and the major sophorolipid-producer S. bombicola were similar at 0.8 gl[-1] h[-1]. S. riodocensis GT-SL1R produced mixed forms of lactonic and acidic sophorolipids, shown by TCL, FTIR, and HPLC. Importantly, the complex sophorolipid mixture displayed antifungal activity against an opportunistic yeast pathogen Candida albicans by effectively reducing hyphal and biofilm formation.

CONCLUSIONS: Sophorolipids derived from S. riodocensis demonstrate potential industrial and biomedical applications as green surfactant and antifungal agent. Since numerous renewable bioresources and industrial wastes could be used by microbial cell factories in the biosynthesis of biosurfactants to reduce the production cost, sophorolipids hold a promising alternative to current antimicrobials in treatments against infectious diseases in humans, animals, and plants.}, } @article {pmid35974361, year = {2022}, author = {Thienngern, P and Panichuttra, A and Ratisoontorn, C and Aumnate, C and Matangkasombut, O}, title = {Efficacy of chitosan paste as intracanal medication against Enterococcus faecalis and Candida albicans biofilm compared with calcium hydroxide in an in vitro root canal infection model.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {354}, pmid = {35974361}, issn = {1472-6831}, mesh = {Agar ; Anti-Bacterial Agents ; *Anti-Infective Agents ; Biofilms ; Calcium Hydroxide/pharmacology/therapeutic use ; Candida albicans ; *Chitosan/pharmacology/therapeutic use ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis ; Humans ; Root Canal Irrigants/pharmacology/therapeutic use ; }, abstract = {BACKGROUND: Enterococcus faecalis and Candida albicans are frequently found in persistent endodontic infection and could remain in dentinal tubules despite intracanal medication with calcium hydroxide (Ca(OH)2), a commonly used medication. Thus, an effective and safe antimicrobial medication against such refractory infection is necessary in endodontic retreatment, so we aimed to test the efficacy of chitosan paste against these microorganisms compared with Ca(OH)2 in root canals of extracted human teeth.

METHODS: Thirty-six sterilized human root samples prepared from extracted premolars and upper maxillary incisors were infected with E. faecalis for 14 days, while 32 were infected with C. albicans for 48 h, for mature biofilm formation. The samples were assigned to 6 groups of intracanal medications: Group 1: no medication (negative control); Group 2: 20% Polyethylene glycol (PEG); Group 3: 20% Propylene glycol (PG); Group 4: Ca(OH)2; Group 5: Chitosan + PEG; and Group 6: Chitosan + PG. After 7 days, intracanal surface dentin was harvested using Protaper next, resuspended, serially diluted and spread on Brain-Heart-Infusion agar (for E. faecalis) and Yeast Extract-Peptone-Dextrose agar (for C. albicans) for colony count. Antimicrobial efficacy was determined as percentage of remaining colony forming unit (CFUs) relative to negative control and analyzed using One-way ANOVA and post-hoc Games-Howell test. The significance level was set at 0.05.

RESULTS: For E. faecalis, chitosan + PG had significantly higher antibacterial activity than Ca(OH)2 (P = 0.039). Chitosan + PEG and chitosan + PG medication significantly reduced viable bacteria compared with negative control, PEG and PG (P = 0.001, 0.003, 0.024, respectively for chitosan + PEG; P = 0.002, 0.003, 0.014, respectively for chitosan + PG). For C.albicans, chitosan + PEG and chitosan + PG were not significantly different from Ca(OH)2. However, Chitosan + PEG and chitosan + PG, but not Ca(OH)2, showed a significantly lower level of remaining CFUs compared with negative control (P = 0.013 and 0.005, respectively).

CONCLUSION: Chitosan paste showed better efficacy in reducing viable E. faecalis biofilm when compared to Ca(OH)2 after 7-day intracanal medication in this in vitro root canal model. It could also significantly reduce viable C. albicans, but was not significantly different from Ca(OH)2.}, } @article {pmid35973647, year = {2022}, author = {Egorova, DA and Solovyev, AI and Polyakov, NB and Danilova, KV and Scherbakova, AA and Kravtsov, IN and Dmitrieva, MA and Rykova, VS and Tutykhina, IL and Romanova, YM and Gintsburg, AL}, title = {Biofilm matrix proteome of clinical strain of P. aeruginosa isolated from bronchoalveolar lavage of patient in intensive care unit.}, journal = {Microbial pathogenesis}, volume = {170}, number = {}, pages = {105714}, doi = {10.1016/j.micpath.2022.105714}, pmid = {35973647}, issn = {1096-1208}, mesh = {Bacterial Proteins/metabolism ; Biofilms ; Bronchoalveolar Lavage ; Extracellular Polymeric Substance Matrix ; Humans ; Intensive Care Units ; *Proteome/metabolism ; *Pseudomonas aeruginosa ; }, abstract = {Extracellular matrix plays a pivotal role in biofilm biology and proposed as a potential target for therapeutics development. As matrix is responsible for some extracellular functions and influence bacterial cytotoxicity against eukaryotic cells, it must have unique protein composition. P. aeruginosa is one of the most important pathogens with emerging antibiotic resistance, but only a few studies were devoted to matrix proteomes and there are no studies describing matrix proteome for any clinical isolates except reference strains PAO1 and ATCC27853. Here we report the first biofilm matrix proteome of P. aeruginosa isolated from bronchoalveolar lavage of patient in intensive care unit. We have identified the largest number of proteins in the matrix among all published studies devoted to P. aeruginosa biofilms. Comparison of matrix proteome with proteome from embedded cells let us to identify several enriched bioprocess groups. Bioprocess groups with the largest number of overrepresented in matrix proteins were oxidation-reduction processes, proteolysis, and transmembrane transport. The top three represented in matrix bioprocesses concerning the size of the GO annotated database were cell redox homeostasis, nucleoside metabolism, and fatty acid synthesis. Finally, we discuss the obtained data in a prism of antibiofilm therapeutics development.}, } @article {pmid35973461, year = {2022}, author = {Zhang, Y and Zhang, J and Li, J and Wei, P and Luo, R and Han, H}, title = {Fast start-up of ANAMMOX biofilm processes at low temperatures by economical quorum sensing regulation: The importance of endogenous N-acyl-homoserine lactones from enhanced inoculated sludge.}, journal = {Environmental research}, volume = {214}, number = {Pt 3}, pages = {114097}, doi = {10.1016/j.envres.2022.114097}, pmid = {35973461}, issn = {1096-0953}, mesh = {*Acyl-Butyrolactones ; Biofilms ; Bioreactors ; *Quorum Sensing ; Sewage ; Temperature ; }, abstract = {The start-up of anaerobic ammonia oxidation (ANAMMOX) processes at low temperatures is quite difficult. In this study, the fast start-up (43 days) of ANAMMOX biofilm processes at 18 ± 3 °C was achieved by adding enhanced ANAMMOX granules (LT-granules) into the inoculated denitrification sludge. The results showed that the addition of LT-granules significantly reduced the duration of the three start-up phases (cell lysis phase, activity lag phase, and activity elevation phase) of reactor R2 compared with the control group R1 without LT-granules. It was demonstrated that LT-granules released high contents of N-hexanoyl-DL-homoserine lactone (C6-HSL), N-octanoyl-DL-homoserine lactone (C8-HSL), and N-3-oxohexanoyl-L-homoserine lactone (3OC6-HSL). The C6-HSL and C8-HSL from LT-granules were strongly positively correlated with the concentrations of polysaccharides (TB-PS) and proteins (TB-PN) in tightly bound extracellular polymeric substances (TB-EPS) in R2 biofilms, respectively. Thus, LT-granules promoted the release of TB-PS and TB-PN from the biofilm in R2 during activity lag and activity elevation phases, improving the biofilm adhesion performance. Furthermore, it was proved that the C6-HSL, C8-HSL, and 3OC6-HSL from LT-granules significantly stimulated the relative abundance of Candidatus Brocadia genus and the expression of functional genes hzo and hzsA in R2 biofilms during activity lag and activity elevation phases. These are the main reasons why adding LT-granules promoted the start-up of reactor R2 at 18 ± 3 °C effectively. This study is the first work to accelerate the start-up of the ANAMMOX biofilm system at the low temperature by the economical quorum sensing (QS) regulation based on endogenous N-acyl-homoserine lactone signals (AHLs) and supply a new way for the rapid start-up of ANAMMOX processes in the low-temperature environment.}, } @article {pmid35972973, year = {2022}, author = {Nicastro, LK and de Anda, J and Jain, N and Grando, KCM and Miller, AL and Bessho, S and Gallucci, S and Wong, GCL and Tükel, Ç}, title = {Assembly of ordered DNA-curli fibril complexes during Salmonella biofilm formation correlates with strengths of the type I interferon and autoimmune responses.}, journal = {PLoS pathogens}, volume = {18}, number = {8}, pages = {e1010742}, pmid = {35972973}, issn = {1553-7374}, support = {R01 AI153325/AI/NIAID NIH HHS/United States ; R21 AI148770/AI/NIAID NIH HHS/United States ; R21 AI151893/AI/NIAID NIH HHS/United States ; }, mesh = {Amyloid/genetics ; Animals ; Autoantibodies ; Autoimmunity ; Bacterial Proteins/metabolism ; Biofilms ; DNA/metabolism ; Humans ; *Interferon Type I/metabolism ; Mice ; Mice, Inbred C57BL ; *Salmonella typhimurium/genetics ; }, abstract = {Deposition of human amyloids is associated with complex human diseases such as Alzheimer's and Parkinson's. Amyloid proteins are also produced by bacteria. The bacterial amyloid curli, found in the extracellular matrix of both commensal and pathogenic enteric bacterial biofilms, forms complexes with extracellular DNA, and recognition of these complexes by the host immune system may initiate an autoimmune response. Here, we isolated early intermediate, intermediate, and mature curli fibrils that form throughout the biofilm development and investigated the structural and pathogenic properties of each. Early intermediate aggregates were smaller than intermediate and mature curli fibrils, and circular dichroism, tryptophan, and thioflavin T analyses confirmed the establishment of a beta-sheet secondary structure as the curli conformations matured. Intermediate and mature curli fibrils were more immune stimulatory than early intermediate fibrils in vitro. The intermediate curli was cytotoxic to macrophages independent of Toll-like receptor 2. Mature curli fibrils had the highest DNA content and induced the highest levels of Isg15 expression and TNFα production in macrophages. In mice, mature curli fibrils induced the highest levels of anti-double-stranded DNA autoantibodies. The levels of autoantibodies were higher in autoimmune-prone NZBWxF/1 mice than wild-type C57BL/6 mice. Chronic exposure to all curli forms led to significant histopathological changes and synovial proliferation in the joints of autoimmune-prone mice; mature curli was the most detrimental. In conclusion, curli fibrils, generated during biofilm formation, cause pathogenic autoimmune responses that are stronger when curli complexes contain higher levels of DNA and in mice predisposed to autoimmunity.}, } @article {pmid35971555, year = {2022}, author = {Sun, W and Ma, L and Li, Y and Xu, Y and Wei, J and Sa, L and Chen, X and Su, J}, title = {In vitro Studies of Non-Diphtheriae Corynebacterium Isolates on Antimicrobial Susceptibilities, Drug Resistance Mechanisms, and Biofilm Formation Capabilities.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {4347-4359}, pmid = {35971555}, issn = {1178-6973}, abstract = {OBJECTIVE: This study aimed to investigate the antimicrobial susceptibilities, drug resistance mechanisms, and biofilm formation capacities of non-diphtheriae Corynebacterium strains isolated from sterile midstream urine of hospitalized patients with clinical urinary tract infections (UTIs).

METHODS: A total of 45 non-diphtheriae Corynebacterium isolates were recovered from sterile midstream urine. The available data of 45 patients were collected. Minimum inhibitory concentrations (MICs) of 10 commonly used antibiotics were determined. Meanwhile, the molecular resistance mechanisms of each agent were performed through PCR with specific primers. Moreover, the biofilm formation capability of each isolate on abiotic surfaces was detected with the MTT method.

RESULTS: In this study, the most prevalent three species were C. striatum (15/45, 33.3%), C. glucuronolyticum (9/45, 20.0%) and C. urealyticum (8/45, 17.8%). These three species also accounted for most renal and ureteral calculi cases. Male patients older than 50 years, especially those with underlying diseases, were more susceptible to non-diphtheriae Corynebacterium infection. All the 45 isolates were 100% susceptible to vancomycin and linezolid, but highly resistant to macrolide-lincosamide-streptogramin B (MLSB), fluoroquinolones, tetracyclines and β-lactams with corresponding mechanisms. The detection rate of multidrug-resistant (MDR) non-diphtheriae Corynebacterium is 91.1%. All isolates are able to form biofilm on abiotic surfaces, except those of C. urealyticum, C. tuberculostearicum and C. jeikeium. Isolates of C. glucuronolyticum and C. Striatum possessed the strongest biofilm formation capacity. C. amycolatum could form biofilm, but varied greatly among different isolates.

CONCLUSION: C. striatum, C. glucuronolyticum and C. urealyticum were the most prevalent species relevant to UTIs. The high occurrence of MDR isolates and high diversities in resistance profiles, and the distinctive abilities of biofilm formation highlighted the urgency for identification to species level. We should pay more attention to the drug resistance profiles of non-diphtheriae Corynebacterium, which would help improve empirical antibiotic therapy and reduce drug resistance transmission.}, } @article {pmid35970352, year = {2022}, author = {Lee, SY and An, J and Kim, J and Kwon, JH}, title = {Enhanced settling of microplastics after biofilm development: A laboratory column study mimicking wastewater clarifiers.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {311}, number = {}, pages = {119909}, doi = {10.1016/j.envpol.2022.119909}, pmid = {35970352}, issn = {1873-6424}, mesh = {Biofilms ; Environmental Monitoring ; *Microplastics ; Plastics ; Polyethylene ; Waste Disposal, Fluid ; Wastewater ; *Water Pollutants, Chemical/analysis ; }, abstract = {The settling of microplastics (MPs) is crucial for their removal from municipal wastewater treatment plants (WWTPs) and sedimentation in static waterbodies, where they can accumulate in bottom sediments. Biofilm formation on MPs enhances their aggregation with other particles, thereby changing their density and size and altering their settling rates. However, only a few studies have investigated the settling of MPs of different sizes and materials. Specifically, the settling of small-sized MPs (<150 μm) has been poorly documented. In this study, cylindrical and fragmented particles of four polymer types (high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and poly(ethylene terephthalate) (PET)) were used to investigate the settling or floating of reference MPs (20-130 μm) in a custom-made column that simulated a primary sedimentation tank in a typical WWTP before and after incubation in wastewater influent. The settling velocity of the reference MP particles was strongly influenced by the particle size and density. The settled fractions of all the cylindrical reference MPs increased significantly (up to 5 times) due to biofilm formation at overflow velocities of 0.15, 0.26, and 0.40 mm s[-1]. This was observed even for HDPE and PP (density <1 g cm[-3]) after biofilm formation. The fragmented reference MPs showed complex and rather unpredictable behavior, possibly due to their irregular shape. Generally, the settling of pristine PS and PET in the laboratory tests was consistent with the theoretical predictions obtained using Stokes' law. The experimental findings of this study can be used to develop models that predict the removal efficiencies of MPs in WWTPs and to estimate the sinking of MPs to bottom sediments of static waterbodies.}, } @article {pmid35970290, year = {2022}, author = {Elfadil, D and Elkhatib, WF and El-Sayyad, GS}, title = {Promising advances in nanobiotic-based formulations for drug specific targeting against multidrug-resistant microbes and biofilm-associated infections.}, journal = {Microbial pathogenesis}, volume = {170}, number = {}, pages = {105721}, doi = {10.1016/j.micpath.2022.105721}, pmid = {35970290}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents ; *Bacterial Infections/drug therapy ; Biofilms ; Drug Delivery Systems ; Drug Resistance, Multiple, Bacterial ; Humans ; *Nanoparticles ; }, abstract = {Antimicrobial agents and alternative strategies to combat bacterial infections have become urgent due to the rapid development of multidrug-resistant bacteria caused by the misuse and overuse of antibiotics, as well as the ineffectiveness of antibiotics against difficult-to-treat infectious diseases. Nanobiotics is one of the strategies being explored to counter the increase in antibiotic-resistant bacteria. Nanobiotics are antibiotic molecules encapsulated in nanoparticles or artificially engineered pure antibiotics that are ≤ 100 nm in size in at least one dimension. Formulation scientists recognize nanobiotic delivery systems as an effective strategy to overcome the limitations associated with conventional antibiotic therapy. This review highlights the general mechanisms by which nanobiotics can be used to target resistant microbes and biofilm-associated infections. We focus on the design elements, properties, characterization, and toxicity assessment of organic nanoparticles, inorganic nanoparticle and molecularly imprinted polymer-based nano-formulations that can be designed to improve the efficacy of nanobiotic formulation.}, } @article {pmid35969071, year = {2022}, author = {Caigoy, JC and Shimamoto, T and Mukhopadhyay, AK and Shinoda, S and Shimamoto, T}, title = {Sequence Polymorphisms in Vibrio cholerae HapR Affect Biofilm Formation under Aerobic and Anaerobic Conditions.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {17}, pages = {e0104422}, pmid = {35969071}, issn = {1098-5336}, mesh = {Anaerobiosis ; Biofilms ; *Cholera/epidemiology ; Humans ; Phylogeny ; *Vibrio cholerae/metabolism ; }, abstract = {We investigated the influence of hapR sequence mutations on the biofilm formation of Vibrio cholerae. In this study, hapR sequences from 85 V. cholerae strains belonging to both pandemic and nonpandemic serogroup were investigated through phylogenetic and sequence analyses. Biofilm formation assays under aerobic and anaerobic conditions were also performed. Sequence variations include single point mutations and insertions/deletions (indels) leading to either truncated or frameshifted HapR. Population structure analysis revealed two major hapR haplogroups, hapR1 and hapR2. Phylogenetic reconstruction displayed a hypothetical ancestral hapR sequence located within the hapR1 haplogroup. Higher numbers of single nucleotide polymorphisms and genetic diversity indices were observed in hapR1, while indels occurred dominantly in hapR2. Aerobic conditions supported more robust biofilms compared to anaerobic conditions. Strains with frameshifted HapR produced the largest amount of biofilm under both oxygen conditions. Quantitative real-time PCR assay confirmed that strains with truncated and frameshifted HapR resulted in a nonfunctional regulator as exhibited by the significantly low hapA gene expression. The present study shows that HapR mutations had a strong influence on biofilm formation and that sequence polymorphisms leading to the disruption of DNA-binding sites or dimerization of the HapR will result in more-robust V. cholerae biofilms. IMPORTANCE Our study revealed an ancestral hapR sequence from a phylogenetic reconstruction that displayed the evolutionary lineage of the nonpandemic to the pandemic strains. Here, we established hapR1 and hapR2 as major hapR haplogroups. The association of the O1 and O139 serogroups with the hapR2 haplogroup demonstrated the distinction of hapR2 in causing cholera infection. Moreover, mutations in this regulator that could lead to the disruption of transcription factor-binding sites or dimerization of the HapR can significantly affect the biofilm formation of V. cholerae. These observations on the relationship of the hapR polymorphism and V. cholerae biofilm formation will provide additional considerations for future biofilm studies and insights into the epidemiology of the pathogen that could ultimately help in the surveillance and mitigation of future cholera disease outbreaks.}, } @article {pmid35969065, year = {2022}, author = {Guo, WY and Zhang, H and Cheng, M and Huang, MR and Li, Q and Jiang, YW and Zhang, JX and Sun, RY and Wang, MG and Liao, XP and Liu, YH and Sun, J and Fang, LX}, title = {Molecular Epidemiology of Plasmid-Mediated Types 1 and 3 Fimbriae Associated with Biofilm Formation in Multidrug Resistant Escherichia coli from Diseased Food Animals in Guangdong, China.}, journal = {Microbiology spectrum}, volume = {10}, number = {5}, pages = {e0250321}, pmid = {35969065}, issn = {2165-0497}, mesh = {Animals ; Anti-Bacterial Agents ; Disinfectants ; Enterobacteriaceae/genetics ; Escherichia coli/genetics ; *Escherichia coli Proteins/genetics/metabolism ; Fimbriae, Bacterial/genetics/metabolism ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Plasmids/genetics ; Drug Resistance, Multiple, Bacterial ; Food Microbiology ; *Biofilms ; *Escherichia coli Infections/veterinary ; }, abstract = {Types 1 and 3 fimbriae in Enterobacteriaceae play versatile roles in bacterial physiology including attachment, invasion, cell motility as well as with biofilm formation and urinary tract infections. Herein, we investigated the prevalence and transmission of plasmid-mediated types 1 and 3 fimbriae from 1753 non-duplicate Enterobacteriaceae from diseased food Animals. We identified 123 (7.01%) strong biofilm producers and all was identified as E. coli. WGS analysis of 43 selected strong biofilm producers revealed that they harbored multiple ARGs, including ESBLs, PMQR and mcr-1. The gene clusters mrkABCDF and fimACDH encoding types 1 and 3 fimbriae, respectively, were identified among 43 (34.96%) and 7 (5.7%) of 123 strong biofilm isolates, respectively. These two operons were able to confer strong biofilm-forming ability to an E. coli weak-biofilm forming laboratory strain. Plasmid analysis revealed that mrk and fim operons were found to co-exist with ARGs and were primarily located on IncX1 and IncFII plasmids with similar backbones, respectively. mrkABCDF operons was present in all of 9457 Klebsiella pneumoniae using archived WGS data, and shared high homology to those on plasmids of 8 replicon types and chromosomes from 6 Enterobacteriaceae species from various origins and countries. In contrast, fimACDH operons was present in most of Enterobacter cloacae (62.15%), and shared high homology to those with only a small group of plasmids and Enterobacteriaceae species. This is the first comprehensive report of the prevalence, transmission and homology of plasmid-encoded type 1 and 3 fimbriae among the Enterobacteriaceae. Our findings indicated that plasmid-encoded mrkABCDF and fimACDH were major contributors to enhanced biofilm formation among E. coli and these two operons, in particular mrk could be as a potential anti-biofilm target. IMPORTANCE Biofilms allow bacteria to tolerate disinfectants and antimicrobials, as well as mammalian host defenses, and are therefore difficult to treat clinically. Most research concerning biofilm-related infections is typically focused on chromosomal biofilm-associated factors, including types 1 and 3 fimbriae of biofilm-forming Enterobacterium. However, the transmission and homology of the mobile types 1 and 3 fimbriae among Enterobacteriaceae is largely unknown. The findings revealed that the plasmid-encoded type 3 fimbriae encoded by mrkABCDF and type 1 fimbriae encoded by fimACDH were major contributors to enhancing biofilm formation among strong biofilm E. coli from diseased food producing animals. Additionally, mrk operon with high homology at an amino acid sequence was present both on plasmids of various replicon types and on chromosomes from diverse Enterobacteriaceae species from numerous origins and countries. These findings provide important information on the transmission of the mobile types 1 and 3 fimbriae among Enterobacteriaceae, indicating a potential antibiofilm target.}, } @article {pmid35968965, year = {2022}, author = {Rouillard, KR and Kissner, WJ and Markovetz, MR and Hill, DB}, title = {Effects of Mucin and DNA Concentrations in Airway Mucus on Pseudomonas aeruginosa Biofilm Recalcitrance.}, journal = {mSphere}, volume = {7}, number = {4}, pages = {e0029122}, pmid = {35968965}, issn = {2379-5042}, support = {T32 HL007106/HL/NHLBI NIH HHS/United States ; }, mesh = {Biofilms ; *Cystic Fibrosis/microbiology ; DNA ; Humans ; Mucins/metabolism ; Mucus/metabolism ; *Pseudomonas aeruginosa ; }, abstract = {The pathological properties of airway mucus in cystic fibrosis (CF) are dictated by mucus concentration and composition, with mucins and DNA being responsible for mucus viscoelastic properties. As CF pulmonary disease progresses, the concentrations of mucins and DNA increase and are associated with increased mucus viscoelasticity and decreased transport. Similarly, the biophysical properties of bacterial biofilms are heavily influenced by the composition of their extracellular polymeric substances (EPS). While the roles of polymer concentration and composition in mucus and biofilm mechanical properties have been evaluated independently, the relationship between mucus concentration and composition and the biophysical properties of biofilms grown therein remains unknown. Pseudomonas aeruginosa biofilms were grown in airway mucus as a function of overall concentration and DNA concentration to mimic healthy, and CF pathophysiology and biophysical properties were evaluated with macro- and microrheology. Biofilms were also characterized after exposure to DNase or DTT to examine the effects of DNA and mucin degradation, respectively. Identifying critical targets in biofilms for disrupting mechanical stability in highly concentrated mucus may lead to the development of efficacious biofilm therapies and ultimately improve CF patient outcomes. Overall mucus concentration was the predominant contributor to biofilm viscoelasticity and both DNA degradation and mucin reduction resulted in compromised biofilm mechanical strength. IMPORTANCE Pathological mucus in cystic fibrosis (CF) is highly concentrated and insufficiently cleared from the airway, causing chronic inflammation and infection. Pseudomonas aeruginosa establishes chronic infection in the form of biofilms within mucus, and this study determined that biofilms formed in more concentrated mucus were more robust and less susceptible to mechanical and chemical challenges compared to biofilms grown in lower concentrated mucus. Neither DNA degradation nor disulfide bond reduction was sufficient to fully degrade biofilms. Mucus rehydration should remain a priority for treating CF pulmonary disease with concomitant multimechanistic biofilm degradation agents and antibiotics to clear chronic infection.}, } @article {pmid35968752, year = {2022}, author = {Wu, W and Mu, Y and Tan, J and Wang, Z and Zhang, C and Li, G and Jin, Y and Huang, X and Han, L}, title = {Discovery of antibacterial agents targeting biofilm formation: total synthesis and in vitro investigation of amycolasporins.}, journal = {Organic & biomolecular chemistry}, volume = {20}, number = {34}, pages = {6831-6843}, doi = {10.1039/d2ob01166b}, pmid = {35968752}, issn = {1477-0539}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; Microbial Sensitivity Tests ; *Staphylococcus aureus ; }, abstract = {Three monoterpene alkaloids amycolasporin A and (±) amycolasporins B and C have been synthesized for the first time from commercially available materials in yields of 31%, 14% and 21%, respectively. Their six analogues (18, 19, 30a and 30d-30f) were synthesized through a similar protocol. Meanwhile, the antibacterial activity of all synthesized molecules was evaluated, showing different levels of bioactivity. Among them, analogue 30d was screened as the most effective antibacterial candidate against E. coli (MIC value, 12.5 μg mL[-1]) and S. aureus (MIC value, 12.5 μg mL[-1]). Further investigation showed that 30d obviously inhibited biofilm formation and disrupted the preformed biofilm of E. coli and S. aureus by promoting intracellular ROS release.}, } @article {pmid35967866, year = {2022}, author = {Hu, S and Lv, Y and Xu, H and Zheng, B and Xiao, Y}, title = {Biofilm formation and antibiotic sensitivity in Elizabethkingia anophelis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {953780}, pmid = {35967866}, issn = {2235-2988}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Cefepime ; Doxycycline ; Flavobacteriaceae ; Humans ; *Minocycline ; Piperacillin ; Rifampin ; }, abstract = {Elizabethkingia anophelis has recently gained global attention and is emerging as a cause of life-threatening nosocomial infections. The present study aimed to investigate the association between antimicrobial resistance and the ability to form biofilm among E. anophelis isolated from hospitalized patients in China. Over 10 years, a total of 197 non-duplicate E. anophelis strains were collected. Antibiotic susceptibility was determined by the standard agar dilution method as a reference assay according to the Clinical and Laboratory Standards Institute. The biofilm formation ability was assessed using a culture microtiter plate method, which was determined using a crystal violet assay. Culture plate results were cross-checked by scanning electron microscopy imaging analysis. Among the 197 isolates, all were multidrug-resistant, and 20 were extensively drug-resistant. Clinical E. anophelis showed high resistance to current antibiotics, and 99% of the isolates were resistant to at least seven antibiotics. The resistance rate for aztreonam, ceftazidime, imipenem, meropenem, trimethoprim-sulfamethoxazole, cefepime, and tetracycline was high as 100%, 99%, 99%, 99%, 99%, 95%, and 90%, respectively. However, the isolates exhibited the highest susceptibility to minocycline (100%), doxycycline (96%), and rifampin (94%). The biofilm formation results revealed that all strains could form biofilm. Among them, the proportions of strong, medium, and weak biofilm-forming strains were 41%, 42%, and 17%, respectively. Furthermore, the strains forming strong or moderate biofilm presented a statistically significant higher resistance than the weak formers (p < 0.05), especially for piperacillin, piperacillin-tazobactam, cefepime, amikacin, and ciprofloxacin. Although E. anophelis was notoriously resistant to large antibiotics, minocycline, doxycycline, and rifampin showed potent activity against this pathogen. The data in the present report revealed a positive association between biofilm formation and antibiotic resistance, which will provide a foundation for improved therapeutic strategies against E. anophelis infections in the future.}, } @article {pmid35964918, year = {2022}, author = {Yang, YR and Wang, XD and Chang, JS and Lee, DJ}, title = {Homogeneously and heterogeneously structured biofilm models for wastewater treatment.}, journal = {Bioresource technology}, volume = {362}, number = {}, pages = {127763}, doi = {10.1016/j.biortech.2022.127763}, pmid = {35964918}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Extracellular Polymeric Substance Matrix ; Wastewater ; *Water Purification ; }, abstract = {Biofilm, a layer comprising extracellular polymeric substances, is the platform where the embedded living cells degrade the substances in the wastewaters. Biofilm models have been developed as part of the comprehensive models for the wastewater treatment process. This review summarizes the biofilm models applied in contemporary literature based on the spatial dimensions adopted for model build-up. The most commonly applied biofilm models are null-dimensional, considering the biofilm active biomass for the substrate sink's biological reaction. The one-dimensional, multi-species models are the second standard models for contemporary studies, providing transport and reaction resistances of substrates in the biofilm matrix and the interactions of competing or collaborating strains in the biofilm. The structural homogeneity of the biofilm challenges the validity of the uniformly structured models, highlighting the need to re-examine the validity of the uniformly structured models. The challenges and prospects of biofilm model developments and applications are outlined.}, } @article {pmid35964716, year = {2022}, author = {Sadaf, S and Singh, AK and Iqbal, J and Kumar, RN and Sulejmanović, J and Habila, MA and Pinê Américo-Pinheiro, JH and Sher, F}, title = {Advancements of sequencing batch biofilm reactor for slaughterhouse wastewater assisted with response surface methodology.}, journal = {Chemosphere}, volume = {307}, number = {Pt 3}, pages = {135952}, doi = {10.1016/j.chemosphere.2022.135952}, pmid = {35964716}, issn = {1879-1298}, mesh = {Abattoirs ; Biofilms ; Bioreactors ; *Environmental Pollutants ; Nitrogen/metabolism ; Oxygen/metabolism ; Phosphorus ; Plastics ; Polyethylenes ; Waste Disposal, Fluid/methods ; *Wastewater ; Water ; }, abstract = {Slaughterhouse wastewater (SWW) contains a significant volume of highly polluted organic wastes. These include blood, fat, soluble proteins, colloidal particles, suspended materials, meat particles, and intestinal undigested food that consists of higher concentrations of organics such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen and phosphorus hence an efficient treatment is required before discharging into the water bodies. The effluent concentrations and performance of simultaneous sequential batch biofilm reactor (SBBR) with recycled plastic carrier media support are better than the local single-stage sequential batch reactor (SBR), which is lacking in the literature in terms of COD, NH3, NO3, and PO4 treatment efficiency. The present study reports a novel strategy to remove the above mentioned contaminants using an intermittently aerated SBBR with recycled plastic carrier media support along with simultaneous nitrification and denitrification. The central composite design was evaluated to optimize the treatment performance of seven different process variables including; different alternating conditions (Oxic/anoxic) for aeration cycles (3/2 h in a 6 h cycle, 6/5 h in a 12 h cycle and 9/8 h in an 18 h cycle) and hydraulic retention time (6, 12 and 18 h). The average removal efficiencies are 94.5% for NH3, 93% for NO3 and 90.1% for PO4, and 99% for COD. The study reveals that the denitrification in the post-anoxic phase was more efficient than the pre-anoxic phase for pollutant removal and maintaining higher quality effluent. The effluent concentrations and performance of simultaneous SBBR with recycled polyethylene carrier support media were better than local SBR system in terms of COD, NH3, NO3 and PO4 treatment efficiency. Results stipulated the suitability of SBBR for wastewater treatment and reusability as a sustainable approach for wastewater management under optimum conditions.}, } @article {pmid35964484, year = {2022}, author = {Niemann, B and Dudas, L and Gray, D and Pettit, A and Wilson, A and Bardes, JM}, title = {Biofilm Formation on Central Venous Catheters: A Pilot Study.}, journal = {The Journal of surgical research}, volume = {280}, number = {}, pages = {123-128}, doi = {10.1016/j.jss.2022.06.072}, pmid = {35964484}, issn = {1095-8673}, support = {P20 RR016440/RR/NCRR NIH HHS/United States ; P30 GM103488/GM/NIGMS NIH HHS/United States ; U54 GM104942/GM/NIGMS NIH HHS/United States ; P20 GM103434/GM/NIGMS NIH HHS/United States ; P30 GM103503/GM/NIGMS NIH HHS/United States ; }, mesh = {Humans ; *Central Venous Catheters/adverse effects ; Chlorhexidine ; *Catheter-Related Infections/etiology/prevention & control ; Pilot Projects ; Biofilms ; *Catheterization, Central Venous/adverse effects/methods ; }, abstract = {INTRODUCTION: Central line-associated bloodstream infection is a complication with serious consequences and biofilm development is thought to play a role. This study evaluated the impact of sterilization technique on central venous catheter (CVC) biofilm formation.

MATERIALS AND METHODS: This pilot study was conducted in the surgical intensive care unit of a tertiary care facility. All CVCs were inserted with chlorhexidine preparation (CHG). CHG-only CVCs were compared to the use of CHG with chlorhexidine gluconate-impregnated sponge (CHGIS). After removal, a punch biopsy of the CVC was taken at the noted skin level. Scanning electron microscopy identified the stage of biofilm. Confocal laser scanning microscopy with SYPRO stain confirmed the presence of glycocalyx and a volumetric analysis was completed.

RESULTS: Twenty four CVCs were collected. Indications for line placement were similar, with 42% placed for sepsis in the CHGIS group and 33% in the CHG group. There were no positive line cultures or bacteremia and 2/12 CHGIS patients had candidemia. CHGIS lines were in place for a mean of 91 h, compared to 60 h with CHG alone (P = 0.19). The interior of CVCs had lower stage biofilms than the exterior and lacked stage 4 biofilms. Stage 4 biofilms were present externally on 50% of CVCs (8/12 CHG and 4/12 CHGIS). Stage 3 biofilms were present on 7/12 CHG and 6/12 CHGIS interior samples. Volume analysis found an increase in biofilm and glycocalyx in CHGIS compared to CHG samples.

CONCLUSIONS: This study identified biofilms on both surfaces of CVCs. No significant difference in biofilm formation was found based on a sterilization technique.}, } @article {pmid35964247, year = {2023}, author = {Kendlbacher, FL and Bloch, S and Hager-Mair, FF and Bacher, J and Janesch, B and Thurnheer, T and Andrukhov, O and Schäffer, C}, title = {Multispecies biofilm behavior and host interaction support the association of Tannerella serpentiformis with periodontal health.}, journal = {Molecular oral microbiology}, volume = {38}, number = {2}, pages = {115-133}, doi = {10.1111/omi.12385}, pmid = {35964247}, issn = {2041-1014}, support = {//Hochschuljubiläumsstiftung der Stadt Wien/ ; /FWF_/Austrian Science Fund FWF/Austria ; }, mesh = {Humans ; Biofilms ; In Situ Hybridization, Fluorescence ; *Periodontitis/microbiology ; Phylogeny ; *Porphyromonas gingivalis/genetics ; *Tannerella forsythia/genetics ; Tannerella ; }, abstract = {The recently identified bacterium Tannerella serpentiformis is the closest phylogenetic relative of Tannerella forsythia, whose presence in oral biofilms is associated with periodontitis. Conversely, T. serpentiformis is considered health-associated. This discrepancy was investigated in a comparative study of the two Tannerella species. The biofilm behavior was analyzed upon their addition and of Porphyromonas gingivalis-each bacterium separately or in combinations-to an in vitro five-species oral model biofilm. Biofilm composition and architecture was analyzed quantitatively using real-time PCR and qualitatively by fluorescence in situ hybridization/confocal laser scanning microscopy, and by scanning electron microscopy. The presence of T. serpentiformis led to a decrease of the total cell number of biofilm bacteria, while P. gingivalis was growth-promoting. This effect was mitigated by T. serpentiformis when added to the biofilm together with P. gingivalis. Notably, T. serpentiformis outcompeted T. forsythia numbers when the two species were simultaneously added to the biofilm compared to biofilms containing T. forsythia alone. Tannerella serpentiformis appeared evenly distributed throughout the multispecies biofilm, while T. forsythia was surface-located. Adhesion and invasion assays revealed that T. serpentiformis was significantly less effective in invading human gingival epithelial cells than T. forsythia. Furthermore, compared to T. forsythia, a higher immunostimulatory potential of human gingival fibroblasts and macrophages was revealed for T. serpentiformis, based on mRNA expression levels of the inflammatory mediators interleukin 6 (IL-6), IL-8, monocyte chemoattractant protein-1 and tumor necrosis factor α, and production of the corresponding proteins. Collectively, these data support the potential of T. serpentiformis to interfere with biological processes relevant to the establishment of periodontitis.}, } @article {pmid35964034, year = {2022}, author = {Yu, J and Wang, F and Shen, Y and Yu, F and Qiu, L and Zhang, L and Chen, Y and Yuan, Q and Zhang, H and Sun, Y and Zhang, K}, title = {Inhibitory effect of ficin on Candida albicans biofilm formation and pre-formed biofilms.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {350}, pmid = {35964034}, issn = {1472-6831}, mesh = {Biofilms ; *Candida albicans ; *Ficain/pharmacology ; Gentian Violet/pharmacology ; Humans ; Microscopy, Confocal ; }, abstract = {BACKGROUND: To investigate the effect of ficin, a type of proteases, on Candida albicans (C. albicans) biofilm, including forming and pre-formed biofilms.

METHODS: Crystal violet tests together with colony forming unit (CFU) counts were used to detect fungal biofilm biomass. Live/dead staining of biofilms observed by confocal laser scanning microscopy was used to monitor fungal activity. Finally, gene expression of C. albicans within biofilms was assessed by qRT-PCR.

RESULTS: According to our results, biofilm biomass was dramatically reduced by ficin in both biofilm formation and pre-formed biofilms, as revealed by the crystal violet assay and CFU count (p < 0.05). Fungal activity in biofilm formation and pre-formed biofilms was not significantly influenced by ficin according to live/dead staining. Fungal polymorphism and biofilm associated gene expression were influenced by ficin, especially in groups with prominent antibiofilm effects.

CONCLUSIONS: In summary, ficin effectively inhibited C. albicans biofilm formation and detached its preformed biofilm, and it might be used to treat C. albicans biofilm associated problems.}, } @article {pmid35963382, year = {2022}, author = {Cai, Y and Luo, YH and Long, X and Zaidi, AA and Shi, Y and Zhou, D and Rittmann, BE}, title = {Wastewater treatment for ships experiencing large temperature changes： the activated sludge/membrane-biofilm reactor.}, journal = {Chemosphere}, volume = {307}, number = {Pt 3}, pages = {135852}, doi = {10.1016/j.chemosphere.2022.135852}, pmid = {35963382}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; *Sewage ; Ships ; Temperature ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {A particular challenge to treatment systems for ship wastewater comes from low and variable temperatures. We evaluated the temperature response (35-15 °C) of a novel biological treatment system involving activated sludge followed by a membrane-biofilm reactor: the activated sludge/membrane-biofilm reactor (AS-ABfMemR). In this study, a pilot-scale AS-ABfMemR achieved over 96% chemical oxygen demand (COD) and 94% total nitrogen (TN) removal from a ship wastewater (550-960 mgCOD·L[-1] and 52-77 mgTN·L[-1]) with a continuous operation with a hydraulic retention time of 12 h at 25 °C. The effluent COD and TN concentrations met IMO discharge standards at temperatures as low as 17 °C, which reduced the energy consumption for wastewater heating. The COD and TN removals of the biofilm stage became important (up to 34% and 35%, respectively) at low temperatures, and this compensated for the deterioration in performance of the aerobic sludge. The genus Azospira dominated in the biofilm's denitrification removal for TN at low temperature. In addition, the buildup of trans-membrane pressure was so slow that backwashing was not needed over the 90 days of continuous operation. These conclusions indicate that the pilot-scale AS-ABfMemR technology is an effective way for real ship sewage treatment under temperature variations.}, } @article {pmid35963131, year = {2022}, author = {Felicetti, T and Cedraro, N and Astolfi, A and Cernicchi, G and Mangiaterra, G and Vaiasicca, S and Massari, S and Manfroni, G and Barreca, ML and Tabarrini, O and Biavasco, F and Cecchetti, V and Vignaroli, C and Sabatini, S}, title = {New C-6 functionalized quinoline NorA inhibitors strongly synergize with ciprofloxacin against planktonic and biofilm growing resistant Staphylococcus aureus strains.}, journal = {European journal of medicinal chemistry}, volume = {241}, number = {}, pages = {114656}, doi = {10.1016/j.ejmech.2022.114656}, pmid = {35963131}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins ; Biofilms ; Ciprofloxacin/pharmacology ; Humans ; *Methicillin-Resistant Staphylococcus aureus/metabolism ; Microbial Sensitivity Tests ; Multidrug Resistance-Associated Proteins ; Plankton/metabolism ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Antimicrobial resistance (AMR) represents a global health issue threatening our social lifestyle and the world economy. Efflux pumps are widely involved in AMR by playing a primary role in the development of specific mechanisms of resistance. In addition, they seem to be involved in the process of biofilm formation and maintenance, contributing to enhance the risk of creating superbugs difficult to treat. Accordingly, the identification of non-antibiotic molecules able to block efflux pumps, namely efflux pump inhibitors (EPIs), could be a promising strategy to counteract AMR and restore the antimicrobial activity of ineffective antibiotics. Herein, we enlarge the knowledge about the structure-activity relationship of 2-phenylquinoline Staphylococcus aureus NorA EPIs by reporting a new series of very potent C-6 functionalized derivatives. Best compounds significantly inhibited ethidium bromide efflux in a NorA-overexpressing S. aureus strain (SA-1199B) and strongly synergized at very low concentrations (0.20-0.78 μg/mL) with ciprofloxacin (CPX) against CPX-resistant S. aureus strains (SA-1199B and SA-K2378), as proved by checkerboard and time-kill experiments. In addition, some of these EPIs (9b and 10a) produced a post-antibiotic effect of 1.2 h and strongly enhanced antibiofilm activity of CPX against SA-1199B strain. Interestingly, at the concentrations used to reach synergy with CPX against resistant S. aureus strains, most of the EPI compounds did not show any human cell toxicity. Finally, by exploiting the recent released crystal structure of NorA, we observed that best EPI 9b highlighted a favourable docking pose, establishing some interesting interactions with key residues.}, } @article {pmid35963093, year = {2022}, author = {Truu, M and Ligi, T and Nõlvak, H and Peeb, A and Tiirik, K and Devarajan, AK and Oopkaup, K and Kasemets, K and Kõiv-Vainik, M and Kasak, K and Truu, J}, title = {Impact of synthetic silver nanoparticles on the biofilm microbial communities and wastewater treatment efficiency in experimental hybrid filter system treating municipal wastewater.}, journal = {Journal of hazardous materials}, volume = {440}, number = {}, pages = {129721}, doi = {10.1016/j.jhazmat.2022.129721}, pmid = {35963093}, issn = {1873-3336}, mesh = {Biofilms ; Humans ; Ions ; *Metal Nanoparticles ; *Microbiota ; Silver/analysis/pharmacology ; Silver Compounds ; Wastewater ; *Water Purification ; }, abstract = {Silver nanoparticles (AgNPs) threaten human and ecosystem health, and are among the most widely used engineered nanomaterials that reach wastewater during production, usage, and disposal phases. This study evaluated the effect of a 100-fold increase in collargol (protein-coated AgNP) and Ag[+] ions concentrations in municipal wastewater on the microbial community composition of the filter material biofilms (FMB) and the purification efficiency of the hybrid treatment system consisting of vertical (VF) and horizontal (HF) subsurface flow filters. We found that increased amounts of collargol and AgNO3 in wastewater had a modest effect on the prokaryotic community composition in FMB and did not significantly affect the performance of the studied system. Regardless of how Ag was introduced, 99.9% of it was removed by the system. AgNPs and AgNO3 concentrations did not significantly affect the purification efficiency of the system. AgNO3 induced a higher increase in the genetic potential of certain Ag resistance mechanisms in VFs than collargol; however, the increase in Ag resistance potential was similar for both substances in HF. Hence, the microbial community composition in biofilms of vertical and horizontal flow filters is largely resistant, resilient, or functionally redundant in response to AgNPs addition in the form of collargol.}, } @article {pmid35962940, year = {2022}, author = {Bakadia, BM and Boni, BOO and Ahmed, AAQ and Zheng, R and Shi, Z and Ullah, MW and Lamboni, L and Yang, G}, title = {In Situ Synthesized Porous Bacterial Cellulose/Poly(vinyl alcohol)-Based Silk Sericin and Azithromycin Release System for Treating Chronic Wound Biofilm.}, journal = {Macromolecular bioscience}, volume = {22}, number = {10}, pages = {e2200201}, doi = {10.1002/mabi.202200201}, pmid = {35962940}, issn = {1616-5195}, mesh = {Animals ; *Anti-Infective Agents ; Azithromycin/pharmacology ; Bacteria ; Biocompatible Materials ; Biofilms ; Cellulose/pharmacology ; Mice ; NIH 3T3 Cells ; Polyvinyl Alcohol/chemistry/pharmacology ; Porosity ; *Sericins/chemistry/pharmacology ; }, abstract = {Chronic wounds are associated with infectious microbial complex communities called biofilms. The management of chronic wound infection is limited by the complexity of selecting an appropriate antimicrobial dressing with antibiofilm activity due to antimicrobial resistance in biofilms. Herein, the in situ developed bacterial cellulose/poly(vinyl alcohol) (BC-PVA) composite is ex situ modified with genipin-crosslinked silk sericin (SS) and azithromycin (AZM) (SSga). The composite is evaluated as a wound dressing material for preventing the development, dispersion, and/or eradication of microbial biofilm. Fourier transform infrared spectroscopy confirms the intermolecular interactions between the components of BC-PVA@SSga scaffolds. The addition of PVA during BC production significantly increases the porosity from 53.5% ± 2.3% to 83.5% ± 2.9%, the pore size from 2.3 ± 1.9 to 16.8 ± 4.5 µm, the fiber diameter from 35.5 ± 10 to 120 ± 27.4 nm, and improves the thermal stability and flexibility. Studies using bacteria and fungi indicate high inhibition and disruption of biofilms upon AZM addition. In vitro biocompatibility analysis confirms the nontoxic nature of BC-PVA@SSga toward HaCaT and NIH3T3 cells, whereas the addition of SS enhances cell proliferation. The developed BC-PVA@SSga accelerates wound healing in the infected mouse model, thus can be a promising wound dressing biomaterial.}, } @article {pmid35962588, year = {2022}, author = {Shariff, M and Chatterjee, M and Morris, SD and Paul, V and Vasudevan, AK and Mohan, CG and Paul-Prasanth, B and Biswas, R}, title = {Enhanced inhibition of Pseudomonas aeruginosa virulence factor production and biofilm development by sublethal concentrations of eugenol and phenyllactic acid.}, journal = {Letters in applied microbiology}, volume = {75}, number = {5}, pages = {1336-1345}, doi = {10.1111/lam.13803}, pmid = {35962588}, issn = {1472-765X}, mesh = {Animals ; *Pseudomonas aeruginosa ; *Virulence Factors/metabolism ; Pyocyanine ; Eugenol/pharmacology ; Biofilms ; Quorum Sensing ; Peptide Hydrolases ; Polyesters ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; }, abstract = {Biofilm development in Pseudomonas aeruginosa is regulated by its quorum sensing (QS) systems. It has three major QS systems: LasI/R, RhlI/R and PQS/MvfR. Previous studies showed that phenyllactic acid (PLA) binds to RhlR and PqsR and inhibits the Rhl and PQS QS; and eugenol at sublethal concentration inhibits Las and PQS QS systems. Here, we have demonstrated that a combination of sublethal doses of eugenol and PLA enhanced the inhibition of the QS mediated production of the virulence factors and biofilm development of this pathogen. A combination of 50 μmol l[-1] eugenol and 0·3 mmol l[-1] PLA significantly inhibited the pyocyanin production, protease activity, swarming motility and cytotoxic activities of P. aeruginosa strain PAO1, whereas eugenol and PLA when added individually to PAO1 cultures were less effective in inhibiting its virulence factor expression. Biofilm formation of PAO1 was reduced by 32, 19 and 87% on glass surfaces; and 54, 49 and 93% on catheter surfaces when treated using 50 μmol l[-1] eugenol or 0·3 mmol l[-1] PLA and their combinations, respectively. The in vitro finding in the reduction of biofilm development was further validated in vivo using a catheter associated medaka fish biofilm model. Our results indicate that a combination of QS inhibitors targeting different QS pathways should be selected while designing therapeutic molecules to achieve maximum QS mediated biofilm inhibition and clinical outcome against P. aeruginosa.}, } @article {pmid35961845, year = {2022}, author = {Luengthamchat, N and Koontongkaew, S and Utispan, K}, title = {Bitter Taste Perception and Dental Biofilm Cariogenicity in Orthodontics.}, journal = {International dental journal}, volume = {72}, number = {6}, pages = {805-810}, pmid = {35961845}, issn = {1875-595X}, mesh = {Child, Preschool ; Humans ; *Taste Perception/genetics ; *Dental Caries/etiology ; Cross-Sectional Studies ; Taste/genetics ; Propylthiouracil/adverse effects ; Biofilms ; Food Preferences ; }, abstract = {BACKGROUND: Bitter taste perception and sweetness preference have been associated with dental caries. Propylthiouracil (PROP) has been used to determine the genetic sensitivity to bitter taste in early childhood caries. However, the role of the bitter threshold in dental biofilm cariogenicity has not been reported. The purpose of this study was to investigate the role of individual taste sensitivity using PROP in dental biofilm cariogenicity in orthodontic patients.

METHODS: Forty orthodontic patients (12-42 years old) undergoing fixed appliance orthodontic treatment participated in this cross-sectional study. Their demographic, oral hygiene practice, and dietary habits data were obtained using a questionnaire. The patients' bitter taste threshold was measured using a PROP assay. The patients were subsequently classified as super-tasters (STs), medium-tasters (MTs), and non-tasters (NTs). Dental biofilm cariogenicity was determined using a 3-tone disclosing gel that becomes pink (new dental biofilm), purple (mature dental biofilm), and light blue (cariogenic dental biofilm) based on dental biofilm maturity.

RESULTS: The NT, MT, and ST groups comprised 10%, 27.5%, and 62.5% of the patients, respectively. Most of the STs (56%) and MTs (63.6%) were female, whereas no females were NTs. The dental biofilm cariogenicity was significantly different between the PROP bitterness groups (P < .05). The highest percentage of mature biofilm, followed by cariogenic and new biofilm, was found in the MT and ST groups. However, the cariogenic biofilm percentage was significantly higher compared with mature biofilm (P < .05) in the NT group. A low frequency (<1 time/d) of sugary and acidic food intake between meals was observed in the ST, MT, and NT groups with no significant difference amongst the groups (P > .05).

CONCLUSIONS: Cariogenic dental biofilm was highly present in orthodontic patients with the NT phenotype.}, } @article {pmid35961522, year = {2022}, author = {Zou, Y and Liu, C and Zhang, H and Wu, Y and Lin, Y and Cheng, J and Lu, K and Li, L and Zhang, Y and Chen, H and Yu, Q}, title = {Three lines of defense: A multifunctional coating with anti-adhesion, bacteria-killing and anti-quorum sensing properties for preventing biofilm formation of Pseudomonas aeruginosa.}, journal = {Acta biomaterialia}, volume = {151}, number = {}, pages = {254-263}, doi = {10.1016/j.actbio.2022.08.008}, pmid = {35961522}, issn = {1878-7568}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; *Chitosan ; Hyaluronic Acid ; *Pseudomonas aeruginosa ; }, abstract = {Surfaces of synthetic materials are highly susceptible to pathogenic bacteria colonization and further biofilm formation, leading to device failure in both biomedical and industrial applications. Complete elimination of the mature biofilms formed on the surfaces, however, remains a great challenge due to the complexity of chemical composition and physical structure. Therefore, prevention of biofilm formation becomes a preferred strategy for solving the biofilm-associated problems. Herein, a multifunctional coating showing three lines of defense to prevent biofilm formation of Pseudomonas aeruginosa is fabricated by a simple and versatile method. This coating is composed of multilayers of quaternized chitosan with bactericidal property and acylase with anti-quorum sensing property and a topmost layer of hyaluronic acid with anti-adhesion property. The substrate deposited with this coating could suppress initial adhesion of a majority of bacteria, and then kill the attached bacteria and interfere with their quorum sensing systems related to biofilm formation. The results of short-term antibacterial experiments show that our coating reduced 98 ± 2% of attached live bacteria. In long-term antibiofilm experiments, this "three lines of defense" design endows the coating with enhanced antibiofilm property against the biofilm formation for at least 3 days by reducing 98 ± 1% of bacterial proliferation and 71 ± 2% of biomass production. Benefiting from the natural building blocks with good biocompatibility and the versatile and environmentally friendly preparation method, this coating shows negligible cytotoxicity and broad applicability, providing great potential for a variety of biomedical applications. STATEMENT OF SIGNIFICANCE: Pathogenic biofilms formed on the surfaces of medical devices and materials pose an urgent problem, and it remains challenging to treat and eradicate the established biofilms. Herein, we developed an antibiofilm coating showing three lines of defense to prevent biofilm formation, which could be deposited on diverse substrates via a simple and versatile method. This coating was based on three natural materials with anti-adhesive, bactericidal, and anti-quorum sensing properties and showed different function in a self-adaptive way to target the sequential stages of biofilm formation by preventing initial bacterial adhesion, killing attached bacteria and interfering with their quorum sensing system to inhibit bacterial proliferation and biofilm maturation. This coating with improved antibiofilm performance might provide a simple and reliable solution to the problems associated with biofilm on surfaces.}, } @article {pmid35961070, year = {2022}, author = {Abd El-Aleam, RH and Sayed, AM and Taha, MN and George, RF and Georgey, HH and Abdel-Rahman, HM}, title = {Design and synthesis of novel benzimidazole derivatives as potential Pseudomonas aeruginosa anti-biofilm agents inhibiting LasR: Evidence from comprehensive molecular dynamics simulation and in vitro investigation.}, journal = {European journal of medicinal chemistry}, volume = {241}, number = {}, pages = {114629}, doi = {10.1016/j.ejmech.2022.114629}, pmid = {35961070}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Benzimidazoles/metabolism/pharmacology ; Biofilms ; *Molecular Dynamics Simulation ; *Pseudomonas aeruginosa/physiology ; Quorum Sensing ; }, abstract = {Quorum sensing (QS) inhibition is one of the potential methods to target bacterial infection. In this study, comprehensive molecular dynamics simulation (MDS) experiments were conducted on the LasR structure to understand its structural dynamic behavior either in its ligand-free form or in its ligand-bound form (i.e. agonist or antagonist). The results revealed that LasR structure is significantly unstable in its ligand-free and antagonist-bound forms and such structural instability led eventually to complete dissociation of the functioning LasR dimeric form. Accordingly, twenty-eight benzimidazole derivatives were designed, synthesized as potential LasR antagonists, and characterized in vitro as QS inhibitors. Compounds 3d and 7f disclosed the highest percentage inhibition in biofilm formation, pyocyanin, and rhamnolipids production in Pseudomonas aeruginosa (71.70%, 68.70%, 54.00%) and (68.90%, 68.00%, 51.80%), respectively. MDS experiments revealed that these compounds as inhibitors, particularly, 3d, 7f, 8a, and 9g induce LasR structure instability and complete dissociation of its functioning dimeric form similarly to the previously reported inhibitor bromophenethyl-2-nitrobenzamide (BPNB). Furthermore, gene expression assays as another mechanism targeting quorum sensing genes to prove the inhibitory activity of these compounds on virulence factors, revealed that a number of the synthesized compounds were able to downregulate lasR (e.g. 3d and 7f by 61.70% and 26.00%, respectively) and rhlR (e.g. 7f by 16.30%) expressions. The results presented here provide a functional model for LasR that could guide future design of LasR inhibitors.}, } @article {pmid35960726, year = {2022}, author = {Nguyen, AV and Shourabi, AY and Yaghoobi, M and Zhang, S and Simpson, KW and Abbaspourrad, A}, title = {A high-throughput integrated biofilm-on-a-chip platform for the investigation of combinatory physicochemical responses to chemical and fluid shear stress.}, journal = {PloS one}, volume = {17}, number = {8}, pages = {e0272294}, pmid = {35960726}, issn = {1932-6203}, mesh = {Antacids ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Escherichia coli ; *Lab-On-A-Chip Devices ; Penicillins/pharmacology ; Pseudomonas aeruginosa ; }, abstract = {Physicochemical conditions play a key role in the development of biofilm removal strategies. This study presents an integrated, double-layer, high-throughput microfluidic chip for real-time screening of the combined effect of antibiotic concentration and fluid shear stress (FSS) on biofilms. Biofilms of Escherichia coli LF82 and Pseudomonas aeruginosa were tested against gentamicin and streptomycin to examine the time dependent effects of concentration and FSS on the integrity of the biofilm. A MatLab image analysis method was developed to measure the bacterial surface coverage and total fluorescent intensity of the biofilms before and after each treatment. The chip consists of two layers. The top layer contains the concentration gradient generator (CGG) capable of diluting the input drug linearly into four concentrations. The bottom layer contains four expanding FSS chambers imposing three different FSSs on cultured biofilms. As a result, 12 combinatorial states of concentration and FSS can be investigated on the biofilm simultaneously. Our proof-of-concept study revealed that the reduction of E. coli biofilms was directly dependent upon both antibacterial dose and shear intensity, whereas the P. aeruginosa biofilms were not impacted as significantly. This confirmed that the effectiveness of biofilm removal is dependent on bacterial species and the environment. Our experimental system could be used to investigate the physicochemical responses of other biofilms or to assess the effectiveness of biofilm removal methods.}, } @article {pmid35960241, year = {2022}, author = {Öcal, D and Tekeli, A and Dolapçı, İ}, title = {[Investigation of Biofilm Formation Properties of Coagulase Negative Staphylococci Isolated from Catheter-Related Bloodstream Infections].}, journal = {Mikrobiyoloji bulteni}, volume = {56}, number = {3}, pages = {506-524}, doi = {10.5578/mb.20229710}, pmid = {35960241}, issn = {0374-9096}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteremia/drug therapy ; Biofilms ; Catheters ; Coagulase/genetics/pharmacology/therapeutic use ; Humans ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; Staphylococcus/genetics ; Vancomycin/pharmacology ; }, abstract = {In view of the significant negative impact of biofilm-mediated infection on patient health and the necessity of a reliable phenotypic method to detect biofilm producers, this study aimed to demonstrate phenotypic and molecular biofilm formation in coagulase-negative staphylococci (CoNS) isolated from catheter related infections and to compare the methods used with each other. The study was also aimed to determine the biofilm eradication effect of vancomycin in order to guide for the treatment. For the detection of biofilm formation, a total of 154 CoNS clinical isolates of which 30 being causative agents of catheter related bloodstream infection (CRBSI) (isolated from both the catheter tip and blood cultures of 15 patients), 89 being isolated from peripheral blood cultures of patients without a central venous catheter (CVC) (13 of them were bloodstream infection agents, 76 of them were contaminant), and 35 being isolated as catheter colonizer, were screened by tissue culture plate (TCP), Congo red agar (CRA) method and polymerase chain reaction (icaA, icaD and IS256). Vancomycin minimum inhibitory concentration (MIC) and minimum biofilm eradicating concentration (MBEC) values were determined. The pulsed field gel electrophoresis (PFGE) method was used to show the clonal relationship between CoNS isolated from the catheter tips and peripheral blood of patients with CRBSI. Of the 154 CoNS isolates included in the study, 38.9% were Staphylococcus epidermidis (n= 60), 34.4% were Staphylococcus haemolyticus (n= 53), 20.7% were Staphylococcus hominis (n= 32), and 3.8% were detected as Staphylococcus capitis (n= 6). In our study, biofilm formation was shown in 31.8% with the CRA method and in 68.1% with the TCP method. By TCP method, 22% (n= 34) were determined as weak, 31.2% (n= 48) medium and 14.9% (n= 23) strong biofilm producers. While the sensitivity of the CRA method was found to be low for isolates that were determined as weak positive in the microplate method, the high sensitivity of the CRA method for isolates with medium and strong positivity was found remarkable. The positivity rates of icaA, icaD and IS256 genes in a total of 154 CoNS isolates were found to be 40 (25.9%), 57 (37%) and 77 (50%), respectively. In total, at least one gene positivity was detected in 107 (69.5%) isolates. Single gene positivity was detected in 55 (35.7%), two gene positivity in 35 (22.7%) and three gene positivity was detected in 17 (11%) of the included CoNS. Biofilm formation (four weak, four medium, two strong) was detected by microplate method in 10 of 47 CoNS isolates (five S.epidermidis, three S.hominis, one S.haemolyticus and one S.capitis) in which no genes were detected. Vancomycin MBEC/ MIC values were found to be high and it was observed that as the biofilm forming power of the isolates increased, the MBEC/MIC ratio also increased. The CoNS isolated from the catheter samples and blood of patients diagnosed with CRBSI had a 100% similar profile with PFGE except for one unevaluable isolate. The tissue culture plate (TCP) method was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation by staphylococci and has the advantage of being a quantitative model to study the adherence of staphylococci. The presence of the icaAD and IS256 gene is not always associated with in vitro biofilm formation. For this reason, it is more appropriate to use more than one method together for the evaluation of biofilm formation. It was thought that the use of reliable methods to specifically detect biofilms could be helpful in diseases that are difficult to treat. Considering the high rates of biofilm and antimicrobial resistance of biofilm-forming isolates in biomedical device associated infections, it was determined that it would not be sufficient to evaluate only the MIC results for susceptibility results.}, } @article {pmid35959369, year = {2022}, author = {Wu, H and Song, L and Yam, JKH and Plotkin, M and Wang, H and Rybtke, M and Seliktar, D and Kofidis, T and Høiby, N and Tolker-Nielsen, T and Song, Z and Givskov, M}, title = {Effects of antibiotic treatment and phagocyte infiltration on development of Pseudomonas aeruginosa biofilm-Insights from the application of a novel PF hydrogel model in vitro and in vivo.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {826450}, pmid = {35959369}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Hydrogels/pharmacology ; Mice ; Microbial Sensitivity Tests ; Phagocytes ; *Pseudomonas Infections/drug therapy/microbiology ; *Pseudomonas aeruginosa ; }, abstract = {BACKGROUND AND PURPOSE: Bacterial biofilm infections are major health issues as the infections are highly tolerant to antibiotics and host immune defenses. Appropriate biofilm models are important to develop and improve to make progress in future biofilm research. Here, we investigated the ability of PF hydrogel material to facilitate the development and study of Pseudomonas aeruginosa biofilms in vitro and in vivo.

METHODS: Wild-type P. aeruginosa PAO1 bacteria were embedded in PF hydrogel situated in vitro or in vivo, and the following aspects were investigated: 1) biofilm development; 2) host immune response and its effect on the bacteria; and 3) efficacy of antibiotic treatment.

RESULTS: Microscopy demonstrated that P. aeruginosa developed typical biofilms inside the PF hydrogels in vitro and in mouse peritoneal cavities where the PF hydrogels were infiltrated excessively by polymorphonuclear leukocytes (PMNs). The bacteria remained at a level of ~10[6] colony-forming unit (CFU)/hydrogel for 7 days, indicating that the PMNs could not eradicate the biofilm bacteria. β-Lactam or aminoglycoside mono treatment at 64× minimal inhibitory concentration (MIC) killed all bacteria in day 0 in vitro biofilms, but not in day 1 and older biofilms, even at a concentration of 256× MIC. Combination treatment with the antibiotics at 256× MIC completely killed the bacteria in day 1 in vitro biofilms, and combination treatment in most of the cases showed significantly better bactericidal effects than monotherapies. However, in the case of the established in vivo biofilms, the mono and combination antibiotic treatments did not efficiently kill the bacteria.

CONCLUSION: Our results indicate that the bacteria formed typical biofilms in PF hydrogel in vitro and in vivo and that the biofilm bacteria were tolerant against antibiotics and host immunity. The PF hydrogel biofilm model is simple and easy to fabricate and highly reproducible with various application possibilities. We conclude that the PF hydrogel biofilm model is a new platform that will facilitate progress in future biofilm investigations, as well as studies of the efficacy of new potential medicine against biofilm infections.}, } @article {pmid35958146, year = {2022}, author = {Summers, S and Pek, YS and Vinod, DP and McDougald, D and Todd, PA and Birch, WR and Rice, SA}, title = {Bacterial biofilm colonization and succession in tropical marine waters are similar across different types of stone materials used in seawall construction.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {928877}, pmid = {35958146}, issn = {1664-302X}, abstract = {Seawalls are important in protecting coastlines from currents, erosion, sea-level rise, and flooding. They are, however, associated with reduced biodiversity, due to their steep orientation, lack of microhabitats, and the materials used in their construction. Hence, there is considerable interest in modifying seawalls to enhance the settlement and diversity of marine organisms, as microbial biofilms play a critical role facilitating algal and invertebrate colonization. We assessed how different stone materials, ranging from aluminosilicates to limestone and concrete, affect biofilm formation. Metagenomic assessment of marine microbial communities indicated no significant impact of material on microbial diversity, irrespective of the diverse surface chemistry and topography. Based on KEGG pathway analysis, surface properties appeared to influence the community composition and function during the initial stages of biofilm development, but this effect disappeared by Day 31. We conclude that marine biofilms converged over time to a generic marine biofilm, rather than the underlying stone substrata type playing a significant role in driving community composition.}, } @article {pmid35956996, year = {2022}, author = {Wang, L and Lv, H and Yang, Q and Chen, Y and Wei, J and Chen, Y and Peng, C and Liu, C and Xu, X and Jia, J}, title = {A Universal Biofilm Reactor Sensor for the Determination of Biochemical Oxygen Demand of Different Water Areas.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {15}, pages = {}, pmid = {35956996}, issn = {1420-3049}, support = {21974097 and 21675147//National Natural Science Foundation of China/ ; 2020KSYS004 and 2020ZDZX2015//Education Department of Guangdong Province/ ; 20190201242JC//Jilin Provincial Science and Technology Development Program/ ; 2019030102360012639 and 2020030102730008711//Science and Technology Bureau of Jiangmen/ ; 202111349019 and pdjh2022b0531//Undergraduate Training Programs/ ; }, mesh = {Biofilms ; *Biosensing Techniques/methods ; Oxygen/chemistry ; Seawater ; Wastewater/chemistry ; *Water/chemistry ; }, abstract = {In this study, we developed a simple strategy to prepare a biofilm reactor (BFR) sensor for the universal biochemical oxygen demand (BOD) determination. The microorganisms in fresh water were domesticated by artificial seawater with different salinity gradients successively to prepare the BFR sensor. The prepared BFR sensor exhibits an efficient ability to degrade a variety of organic substances. The linear range of BOD determination by the BFR sensor is 1.0-10.0 mg/L[-1] with a correlation coefficient of 0.9951. The detection limit is 0.30 mg/L according to three times of signal-to-noise ratio. What is more, the BFR sensor displayed excellent performances for the BOD determination of different water samples, including both fresh water and seawater. The 16S-rRNA gene sequencing technology was used to analyze the microbial species before and after the domestication. The results show that it is a general approach for the rapid BOD determination in different water samples.}, } @article {pmid35956958, year = {2022}, author = {Molina Bertrán, SDC and Monzote, L and Cappoen, D and Escalona Arranz, JC and Gordillo Pérez, MJ and Rodríguez-Ferreiro, AO and Chill Nuñez, I and Novo, CP and Méndez, D and Cos, P and Llauradó Maury, G}, title = {Inhibition of Bacterial Adhesion and Biofilm Formation by Seed-Derived Ethanol Extracts from Persea americana Mill.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {15}, pages = {}, pmid = {35956958}, issn = {1420-3049}, support = {CU 2019 IUC 030A105//Vlaamse Interuniversitaire Raad/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Bacterial Adhesion/drug effects ; *Biofilms/drug effects ; Ethanol ; Mammals ; *Persea ; *Plant Extracts/pharmacology ; Pseudomonas aeruginosa/drug effects ; Seeds ; }, abstract = {The increase in antibiotic resistance demands innovative strategies to combat microorganisms. The current study evaluated the antibacterial and antivirulence effects of ethanol extracts from Persea americana seeds obtained by the Soxhlet (SE) and maceration (MaE) methods. The UHPLC-DAD-QTOF analysis showed mainly the presence of polyphenols and neolignan. Ethanol extracts were not cytotoxic to mammalian cells (CC50 > 500 µg/mL) and displayed a moderate antibacterial activity against Pseudomonas aeruginosa (IC50 = 87 and 187 µg/mL) and Staphylococcus aureus (IC50 = 144 and 159 µg/mL). Interestingly, no antibacterial activity was found against Escherichia coli. SE and MaE extracts were also able to significantly reduce the bacterial adhesion to A549 lung epithelial cells. Additionally, both extracts inhibited the biofilm growth at 24 h and facilitated the release of internal cell components in P. aeruginosa, which might be associated with cell membrane destabilization. Real-time PCR and agarose electrophoresis gel analysis indicated that avocado seed ethanol extracts (64 µg/mL) downregulated virulence-related factors such as mexT and lasA genes. Our results support the potential of bioproducts from P. americana seeds as anti-adhesive and anti-biofilm agents.}, } @article {pmid35956807, year = {2022}, author = {Rajput, A and Bhamare, KT and Thakur, A and Kumar, M}, title = {Biofilm-i: A Platform for Predicting Biofilm Inhibitors Using Quantitative Structure-Relationship (QSAR) Based Regression Models to Curb Antibiotic Resistance.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {15}, pages = {}, pmid = {35956807}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Drug Resistance, Microbial ; *Quantitative Structure-Activity Relationship ; Support Vector Machine ; }, abstract = {Antibiotic drug resistance has emerged as a major public health threat globally. One of the leading causes of drug resistance is the colonization of microorganisms in biofilm mode. Hence, there is an urgent need to design novel and highly effective biofilm inhibitors that can work either synergistically with antibiotics or individually. Therefore, we have developed a recursive regression-based platform "Biofilm-i" employing a quantitative structure-activity relationship approach for making generalized predictions, along with group and species-specific predictions of biofilm inhibition efficiency of chemical(s). The platform encompasses eight predictors, three analysis tools, and data visualization modules. The experimentally validated biofilm inhibitors for model development were retrieved from the "aBiofilm" resource and processed using a 10-fold cross-validation approach using the support vector machine and andom forest machine learning techniques. The data was further sub-divided into training/testing and independent validation sets. From training/testing data sets the Pearson's correlation coefficient of overall chemicals, Gram-positive bacteria, Gram-negative bacteria, fungus, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Escherichia coli was 0.60, 0.77, 0.62, 0.77, 0.73, 0.83, 0.70, and 0.71 respectively via Support Vector Machine. Further, all the QSAR models performed equally well on independent validation data sets. Additionally, we also checked the performance of the random forest machine learning technique for the above datasets. The integrated analysis tools can convert the chemical structure into different formats, search for a similar chemical in the aBiofilm database and design the analogs. Moreover, the data visualization modules check the distribution of experimentally validated biofilm inhibitors according to their common scaffolds. The Biofilm-i platform would be of immense help to researchers engaged in designing highly efficacious biofilm inhibitors for tackling the menace of antibiotic drug resistance.}, } @article {pmid35956712, year = {2022}, author = {Han, J and Poma, A}, title = {Molecular Targets for Antibody-Based Anti-Biofilm Therapy in Infective Endocarditis.}, journal = {Polymers}, volume = {14}, number = {15}, pages = {}, pmid = {35956712}, issn = {2073-4360}, abstract = {Infective endocarditis (IE) is a heart disease caused by the infection of heart valves, majorly caused by Staphilococcus aureus. IE is initiated by bacteria entering the blood circulation in favouring conditions (e.g., during invasive procedures). So far, the conventional antimicrobial strategies based on the usage of antibiotics remain the major intervention for treating IE. Nevertheless, the therapeutic efficacy of antibiotics in IE is limited not only by the bacterial drug resistance, but also by the formation of biofilms, which resist the penetration of antibiotics into bacterial cells. To overcome these drawbacks, the development of anti-biofilm treatments that can expose bacteria and make them more susceptible to the action of antibiotics, therefore resulting in reduced antimicrobial resistance, is urgently required. A series of anti-biofilm strategies have been developed, and this review will focus in particular on the development of anti-biofilm antibodies. Based on the results previously reported in the literature, several potential anti-biofilm targets are discussed, such as bacterial adhesins, biofilm matrix and bacterial toxins, covering their antigenic properties (with the identification of potential promising epitopes), functional mechanisms, as well as the antibodies already developed against these targets and, where feasible, their clinical translation.}, } @article {pmid35954005, year = {2022}, author = {He, S and Zhan, Z and Shi, C and Wang, S and Shi, X}, title = {Ethanol at Subinhibitory Concentrations Enhances Biofilm Formation in Salmonella Enteritidis.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {15}, pages = {}, pmid = {35954005}, issn = {2304-8158}, support = {2019YFE0119700//National Key Research and Development Program of China/ ; 32001797//National Natural Science Foundation of China/ ; 19391902100//Science and Technology Innovation Agricultural Project of Shanghai Science and Technology Commission/ ; 22ZR1429900//Natural Science Foundation of Shanghai/ ; 22X010500276//Startup Fund for Young Faculty at SJTU/ ; }, abstract = {The survival of Salmonella Enteritidis in the food chain is relevant to its biofilm formation capacity, which is influenced by suboptimal environmental conditions. Here, biofilm formation pattern of this bacterium was assessed in the presence of ethanol at sub-minimal inhibitory concentrations (sub-MICs) by microtiter plate assays, cell characteristic analyses, and gene expression tests. It was observed that ethanol at subinhibitory concentrations (1/4 MIC, 2.5%; 1/2 MIC, 5.0%) was able to stimulate biofilm formation in S. Enteritidis. The OD595 value (optical density at 595 nm) used to quantify biofilm production was increased from 0.14 in control groups to 0.36 and 0.63 under 2.5% and 5.0% ethanol stresses, respectively. Ethanol was also shown to reduce bacterial swimming motility and enhance cell auto-aggregation ability. However, other cell characteristics such as swarming activity, initial attachment and cell surface hydrophobicity were not remarkedly impacted by ethanol. Reverse transcription quantitative real-time PCR (RT-qPCR) analysis further revealed that the luxS gene belonging to a quorum-sensing system was upregulated by 2.49- and 10.08-fold in the presence of 2.5% and 5.0% ethanol, respectively. The relative expression level of other biofilm-related genes (adrA, csgB, csgD, and sdiA) and sRNAs (ArcZ, CsrB, OxyS, and SroC) did not obviously change. Taken together, these findings suggest that decrease in swimming motility and increase in cell auto-aggregation and quorum sensing may result in the enhancement of biofilm formation by S. Enteritidis under sublethal ethanol stress.}, } @article {pmid35952860, year = {2022}, author = {Yang, X and Tang, Z and Xiao, L and Zhang, S and Jin, J and Zhang, S}, title = {Effect of electric current intensity on performance of polycaprolactone/FeS2-based mixotrophic biofilm-electrode reactor.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127757}, doi = {10.1016/j.biortech.2022.127757}, pmid = {35952860}, issn = {1873-2976}, mesh = {Autotrophic Processes ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Electrodes ; Iron ; *Nitrates/metabolism ; Nitrogen/metabolism ; Polyesters ; Sulfides ; }, abstract = {In this study, a bioelectrochemical system consisting of pyrite-based autotrophic denitrification (PAD) and heterotrophic denitrification (HD) was established to polish nitrate wastewater. The loading of electric current (EC) could stimulate the dissolution of pyrite. Appropriate EC (I ≤ 30 mA) was conducive to nitrate removal, too high EC (I = 40 mA) would inhibit nitrate removal and lead to an obvious accumulation of NO2[-]-N and NH4[+]-N. Microbial analysis revealed that the increase of EC could inhibit the diversity of heterotrophic microbes, but appropriate EC (I = 10 mA) could increase the diversity of autotrophic microbes. The EC loading was conducive to the enrichment of iron autotrophic denitrifiers (Ferritrophicum), pyrite-oxidizing bacteria (Thiobacillus, Sulfurimonas), and sulfur autotrophic denitrifiers (Dechloromonas, Thiobacillus, and Arenimonas). The EC loading enlarged the contribution of PAD, making PAD a dominant pathway in denitrification.}, } @article {pmid35952666, year = {2022}, author = {Gupta, A and Maruthapandi, M and Das, P and Saravanan, A and Jacobi, G and Natan, M and Banin, E and Luong, JHT and Gedanken, A}, title = {Cuprous Oxide Nanoparticles Decorated Fabric Materials with Anti-biofilm Properties.}, journal = {ACS applied bio materials}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsabm.2c00508}, pmid = {35952666}, issn = {2576-6422}, abstract = {Considering the global spread of bacterial infections, the development of anti-biofilm surfaces with high antimicrobial activities is highly desired. This work unraveled a simple, sonochemical method for coating Cu2O nanoparticles (NPs) on three different flexible substrates: polyester (PE), nylon 2 (N2), and polyethylene (PEL). The introduction of Cu2O NPs on these substrates enhanced their surface hydrophobicity, induced ROS generation, and completely inhibited the growth of sensitive (Escherichia coli and Staphyloccocus aureus) and drug-resistant (MDR E. coli and MRSA) planktonic and biofilm. The experimental results confirmed that Cu2O-PE exhibited complete biofilm mass reduction ability for all four strains, whereas Cu2O-N2 showed more than 99% biomass inhibition against both drug-resistant and sensitive pathogens in 6 h. Moreover, Cu2O-PEL also indicated a 99.95, 97.73, 98.00, and 99.20% biomass reduction of MRSA, MDR E. coli, E. coli, and S. aureus, respectively. All substrates were investigated for time-dependent inhibitions, and the associated biofilm mass and log reduction were evaluated. The mechanisms of Cu2O NP action against the mature biofilms include the generation of reactive oxygen species (ROS) as well as electrostatic interaction between Cu2O NPs and bacterial membranes. The current study could pave the way for the commercialization of sonochemically coated Cu2O NP flexible substrates for the prevention of microbial contamination in hospitals and industrial environments.}, } @article {pmid35952376, year = {2022}, author = {Liu, P and Dai, J and Bie, C and Li, H and Zhang, Z and Guo, X and Zhu, L}, title = {Bioaccessibility of Microplastic-Associated Antibiotics in Freshwater Organisms: Highlighting the Impacts of Biofilm Colonization via an In Vitro Protocol.}, journal = {Environmental science & technology}, volume = {56}, number = {17}, pages = {12267-12277}, doi = {10.1021/acs.est.2c02782}, pmid = {35952376}, issn = {1520-5851}, mesh = {Anti-Bacterial Agents/pharmacology ; Aquatic Organisms ; Biofilms ; Environmental Monitoring ; Fresh Water/chemistry ; *Microplastics ; Plastics/pharmacology ; Sulfamethazine/pharmacology ; *Water Pollutants, Chemical/chemistry ; }, abstract = {Microplastics in the environment can be colonized by microbes capable of forming biofilms, which may act as reactive coatings to affect the bioaccessibility of pollutants in organisms. This study investigated the dynamic evolution of biofilm colonization on microplastics and its impacts and mechanisms on the bioaccessibility of microplastic-associated sulfamethazine (SMT) via microcosm incubation in surface water and sediment. After 60 days of incubation, the microbial communities formed in microplastics were distinct and more diverse than those untethered in surroundings, and photoaging treatment decreased the affinity of biofilms on microplastics due to decreased hydrophobicity. Biofilm formation further enhanced the desorption and bioaccessibility of microplastic-sorbed SMT in organisms. In vitro experiments indicated that the critical effects were mainly related to the stronger interaction of gastrointestinal components (i.e., pepsin, bovine serum albumin (BSA), and NaT) with biofilm components (e.g., extracellular polymer substances) than with the pure surface of microplastics, which competed for binding sites in microplastics for SMT more significantly. Photoaging decreased the enhancing effects of biofilms due to their lower accumulation in aged microplastics. This study is the first attempt to reveal the role of biofilms in the bioaccessibility of microplastics with associated antibiotics and provide insights into the combined risk of microplastics in the environment.}, } @article {pmid35951737, year = {2022}, author = {Pan, D and Wang, XY and Zhou, JW and Yang, L and Khan, A and Wei, DQ and Li, JJ and Jia, AQ}, title = {Virulence and biofilm inhibition of 3-methoxycinnamic acid against Agrobacterium tumefaciens.}, journal = {Journal of applied microbiology}, volume = {133}, number = {5}, pages = {3161-3175}, doi = {10.1111/jam.15774}, pmid = {35951737}, issn = {1365-2672}, support = {TJ-2021-066//Jiangsu Youth Talent Promotion Project/ ; 20KJB180019//General Projects of Natural Science Research in Universities of Jiangsu Province/ ; 221CXTD434//Natural Science Foundation of Hainan Province/ ; 319QN165//Natural Science Foundation of Hainan Province/ ; }, mesh = {*Agrobacterium tumefaciens/metabolism ; Molecular Docking Simulation ; Gentian Violet/metabolism/pharmacology ; Quorum Sensing ; Biofilms ; 4-Butyrolactone ; Phenols/pharmacology ; *Pesticides/pharmacology ; beta-Galactosidase/metabolism ; }, abstract = {AIMS: In the current study the anti-virulence and anti-biofilm activities of the cinnamic acid derivative, 3-methoxycinnamic acid, was investigated against Agrobacterium tumefaciens.

METHODS AND RESULTS: Based on the disc diffusion test and β-galactosidase activity assay, 3-methoxycinnamic acid was shown to interfere with the quorum sensing (QS) system of A. tumefaciens. Crystal violet staining assay, phenol-sulfuric acid method, Bradford protein assay and confocal laser scanning microscopy (CLSM) revealed that the biofilm formation of A. tumefaciens was inhibited after the treatment of 3-methoxycinnamic acid. Employing high-performance liquid chromatography (HPLC) analysis of culture supernatant revealed that the production of 3-oxo-octanoylhomoserine lactone (3-oxo-C8-HSL) decreased concentration-dependently after treatment with 3-methoxycinnamic acid. Swimming and chemotaxis assays also indicated that 3-methoxycinnamic acid had a good effect on reducing the motility and chemotaxis of A. tumefaciens. In addition, the RT-qPCR, molecular docking and simulations further demonstrated that 3-methoxycinnamic acid could competitively inhibit the binding of 3-oxo-C8-HSL to TraR and down-regulate virulence-related genes.

CONCLUSIONS: 3-Methoxycinnamic acid is proved to have good anti-virulence and anti-biofilm activities against A. tumefaciens.

This is the first study that investigates the anti-virulence and anti-biofilm activities of 3-methoxycinnamic acid against A. tumefaciens. With its potential QS-related virulence and biofilm inhibitory activities, 3-methoxycinnamic acid is expected to be developed as a potent pesticide or adjuvant for the prevention and treatment of crown gall caused by A. tumefaciens.}, } @article {pmid35951268, year = {2022}, author = {Díaz, PR and Torres, MJ and Petroselli, G and Erra-Balsells, R and Audisio, MC}, title = {Antibacterial activity of Bacillus licheniformis B6 against viability and biofilm formation of foodborne pathogens of health importance.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {10}, pages = {181}, pmid = {35951268}, issn = {1573-0972}, mesh = {Ampicillin ; Anti-Bacterial Agents/pharmacology ; *Bacillus licheniformis/genetics ; Biofilms ; Escherichia coli ; Humans ; Lipopeptides/chemistry/pharmacology ; Peptides, Cyclic ; Phylogeny ; }, abstract = {We studied a strain of Bacillus isolated from an artisanal tannery in Salta, Argentina. It was identified as Bacillus licheniformis B6 by 16 S phylogenetic analysis and MALDI TOF (GenBank accession code No. KP776730). The synthesis of lipopeptides by B6 and their antibacterial activity against clinical pathogenic strains was analyzed both in the cell-free supernatant (CFS) and in the crude fraction of lipopeptides (LF). Overall, the CFS did not significantly reduce the viability of the studied strains (Staphylococcus aureus 269 and ATCC 43,300, Escherichia coli 4591 and 25,922, Klebsiella sp. 1087 and 1101). However, LF at 9 mg/mL reduced the viability of those pathogenic strains by 2 and 3 log orders compared to those of the control. When the effects of LF and ampicillin were compared, they showed different sensitivity against pathogenic strains. For example, E. coli 4591 was the strain most resistant to ampicillin, requiring 250 mg/mL of antibiotic to achieve the same inhibitory effect as 9 mg/mL of B6 LF. SEM observations of the effect of LF on biofilm formation by E. coli 4591 and Klebsiella sp. 1087 clearly showed that biofilm structures were destabilized, these strains turning into weak biofilm formers. Signals in the CFS and LF corresponding to kurstakin and iturin were identified by MALDI TOF. Interestingly, surfactin was detected, rather than lichenysin, the expected lipopeptide in B. licheniformis species. Signals of bacitracin and fengycins were also found, the latter with a higher number of homologues and relative intensity in the LF than the other lipopeptides. These results show that the lipopeptides synthesized by B. licheniformis B6 have both potential antibacterial and anti-biofilm activity against pathogenic bacteria of health importance.}, } @article {pmid35950855, year = {2022}, author = {Shay, R and Wiegand, AA and Trail, F}, title = {Biofilm Formation and Structure in the Filamentous Fungus Fusarium graminearum, a Plant Pathogen.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0017122}, pmid = {35950855}, issn = {2165-0497}, mesh = {Biofilms ; *Fusarium/physiology ; Hyphae ; Plant Diseases/microbiology ; }, abstract = {Biofilms are protective structures for pathogens of plants and animals, in which cells are shielded from host defense responses and antimicrobial treatments. Although biofilms are well studied in bacterial pathogens, their development and structure in filamentous fungi, as well as their role in pathogenicity, are poorly understood. We show that the economically important plant pathogen Fusarium graminearum, a filamentous fungus, forms biofilms in vitro, which adhere to polystyrene, a hydrophobic surface. The biofilms have complex hyphal structures surrounded by a polymeric matrix that consists primarily of polysaccharides and extracellular nucleic acids, and lack lipids. Pellicles are formed in liquid cultures, floating biofilm masses that are common in bacterial biofilms, and noted but undescribed in filamentous fungal biofilms. Commonly, F. graminearum grows as hyphal colonies; however, on media which lack electron acceptors, an altered morphology is formed with predominantly short, bulbous hyphae embedded in the matrix. Supplementation of the biofilm-inducing medium with an electron acceptor restores the filamentous hyphal morphology, demonstrating that the formation of bulbous hyphae is due, at least in part, to oxidative stress. Plant hosts infected with pathogens generally respond by producing reactive oxygen species, commonly produced as a defense response. Thus, the formation of biofilms strongly suggests a role in protecting cells from host responses during the course of plant disease. IMPORTANCE Fusarium graminearum is a filamentous fungal pathogen that causes Fusarium head blight (FHB) in cereal crops, leading to devastating crop losses. We have demonstrated the ability of this pathogen to form biofilms. Biofilms are likely to be important in the disease cycle of F. graminearum and other plant pathogens, protecting cells from plant defenses and environmental conditions. Towards this end, we have characterized the formation of biofilms in F. graminearum in vitro, which, together with ongoing characterization of their association with host plants, provides a basis for understanding the functionality of biofilms in the pathogen disease cycle.}, } @article {pmid35950539, year = {2022}, author = {Boullosa-Falces, D and Sanz, DS and Garcia, S and Trueba-Castañeda, L and Trueba, A}, title = {Predicting tubular heat exchanger efficiency reduction caused by marine biofilm adhesion using CFD simulations.}, journal = {Biofouling}, volume = {38}, number = {7}, pages = {663-673}, doi = {10.1080/08927014.2022.2110493}, pmid = {35950539}, issn = {1029-2454}, mesh = {*Biofilms ; Computer Simulation ; Hot Temperature ; *Hydrodynamics ; Seawater ; }, abstract = {A novel efficiency reduction model to tubular heat exchanger based on heat transfer losses by biofilm adhesion is proposed, which included a modified equation based on the real data-dependent time, seawater, hydrodynamics and heat transfer resistance using computational fluid dynamics (CFD). The biofilm growth model based on Verhulst model and experimental data has been obtained and simulated in a CFD software tool to analyze the tubular heat exchanger performance prediction cooled by seawater. The biofilm CFD model with appropriate fit, and the correlation coefficient (R2) values are between 0.97 and 0.99, was validated by experimental data obtained at different flow velocity. The final results of in/outlet difference temperatures were from 3.9 °C to 2.2 °C for different flow velocity with R2 > 0.97. The simulation results demonstrate that the novel CFD model is capable of predicting the efficiency losses during the development period of biofilm growth in in open-loop cooling seawater systems.}, } @article {pmid35948833, year = {2022}, author = {Díaz-Pérez, SP and Solis, CS and López-Bucio, JS and Valdez Alarcón, JJ and Villegas, J and Reyes-De la Cruz, H and Campos-Garcia, J}, title = {Pathogenesis in Pseudomonas aeruginosa PAO1 Biofilm-Associated Is Dependent on the Pyoverdine and Pyocyanin Siderophores by Quorum Sensing Modulation.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, pmid = {35948833}, issn = {1432-184X}, support = {256119//Consejo Nacional de Ciencia y Tecnología/ ; 2.14//Universidad Michoacana de San Nicolás de Hidalgo/ ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogenic bacterium for humans, animals, and plants, through producing different molecular factors such as biofilm, siderophores, and other virulence factors which favor bacterial establishment and infection in the host. In P. aeruginosa PAO1, the production of these factors is regulated by the bacterial quorum sensing (QS) mechanisms. From them, siderophores are involved in iron acquisition, transport, and homeostasis. They are also considered some of the main virulence factors in P. aeruginosa; however, detailed mechanisms to induce bacterial pathogenesis are poorly understood. In this work, through reverse genetics, we evaluated the function of bacterial pathogenesis in the pvd cluster genes, which are required for synthesizing the siderophore pyoverdine (PVD). Single pvdI, pvdJ, pvdL, and double mutant strains were analyzed, and contrary to expected, the pvdL and pvdI mutations increased the concentration of PVD and other phenazines, such as pyocyanin (PYO) and phenazine-1-carboxylic acid (PCA) and also an increased biofilm production and morphology depending on the autoinducer 2-alkyl-4-quinolone (PQS) and the QS molecules acyl-homoserine lactones. Consequently, in the in vivo pathogenicity model of Caenorhabditis elegans, the mutations in pvdI, pvdJ, and pvdL increased the survival of the worms exposed to supernatants or biofilms of the bacterial cultures. However, the double mutant pvdI/pvdJ increased its toxicity in agreeing with the biofilm production, PVD, PYO, and PCA. The findings indicate that the mutations in pvd genes encode non-ribosomal peptide synthetases impacted the biofilm's structure, but suppressively also of the phenazines, confirming that the siderophores contribute to the bacterial establishment and pathogenicity of P. aeruginosa PAO1.}, } @article {pmid35947311, year = {2023}, author = {Ataabadi, M and Hoodaji, M and Tahmourespour, A}, title = {Chromium (VI) bioremoval from contaminated wastewater using Pseudomonas aeruginosa ATHA23 producing biofilm supported on clinoptilolite.}, journal = {Environmental geochemistry and health}, volume = {45}, number = {2}, pages = {427-442}, doi = {10.1007/s10653-022-01345-2}, pmid = {35947311}, issn = {1573-2983}, mesh = {*Pseudomonas aeruginosa/genetics ; Wastewater ; Chromium/analysis ; Adsorption ; Sulfates/analysis ; *Water Pollutants, Chemical/analysis ; }, abstract = {More has yet to be investigated on the increased efficiency of microbes for the removal of heavy metals from industrial wastewaters. The objective was to determine the Cr (VI) bioabsorption and bioreduction ability of biofilm-producing bacteria supported on clinoptilolite from contaminated aqueous solutions. Chromium (VI)-tolerant bacteria, namely Pseudomonas aeruginosa ATHA23, were identified by biochemical methods and 16S rDNA sequencing and were deposited in NCBI (accession number: KF680991). Preparation of clinoptilolite, bacterial growth and isolation, biofilm production including extracellular polysaccharides (EPS) and Cr (VI) removal efficiency, affected by the experimental treatments, were investigated. The use of FTIR characterized clinoptilolite properties with and without biofilm in the presence and absence of Cr (IV). Higher Cr (VI) levels in the bacterial growth medium, increased EPS production with the highest value (0.171 mg L[-1]), produced 18 h after treating the bacteria with Cr (VI) (100 mg L[-1]). However, in the absence of Cr (VI), EPS significantly decreased to 0.117 mg L[-1]. Plackett-Burman and Taguchi statistical analyses were used to optimize the experimental treatments affecting the removal efficiency of Cr (VI). Among the anions (nitrate, sulfate, and chloride), sulfate decreased Cr removal efficiency. The absorption data were best fitted to the pseudo-second order, and the data of Cr adsorption by clinoptilolite-biofilm were also better fitted to Freundlich isotherm model. The Cr (VI) bioremediation potential of P. aeruginosa ATHA23 by the production of biofilm supported on clinoptilolite has been shown for the first time, which is of significance for the environment and the industry.}, } @article {pmid35946735, year = {2022}, author = {Díaz-Garrido, N and Lozano, CP and Kreth, J and Giacaman, RA}, title = {Extended biofilm formation time by Streptococcus sanguinis modifies its non-cariogenic behavior, in vitro.}, journal = {Brazilian oral research}, volume = {36}, number = {}, pages = {e107}, doi = {10.1590/1807-3107bor-2022.vol36.0107}, pmid = {35946735}, issn = {1807-3107}, mesh = {Biofilms ; *Dental Caries ; Humans ; Streptococcus mutans ; *Streptococcus sanguis ; Sucrose ; }, abstract = {Although the commensal Streptococcus sanguinis [ S. sanguinis] is isolated from caries-free people, it can ferment carbohydrates producing acids. We aimed to characterize S. sanguinis cariogenic potential as a function of different enamel biofilm formation periods, in vitro. Saliva-coated enamel slabs were inoculated with S. sanguinis to form initial biofilms for 8, 12 or 16 h in presence of sucrose and followed by a period in medium with glucose for 16, 12 or 8 h, respectively, until completion of 24 h. To simulate cariogenic challenges, S. sanguinis biofilms were exposed to 10% sucrose for 5 minutes, 3x/day for 5 days. Biofilm biomass, viable cells, total proteins, intracellular and extracellular polysaccharides production, acidogenicity and enamel demineralization were determined. Biofilms of Streptococcus mutans [ S. mutans ] served as caries-positive control. Biofilms of S. sanguinis forming on enamel for 12 and 16 h showed higher demineralization than those formed during 8 h, but lower than S. mutans biofilms, regardless of the initial biofilm formation time. No differences were detected in the biofilm properties among the different biofilm formation times tested for S. sanguinis . Increased enamel initial biofilm formation time by S. sanguinis appears to induce a cariogenic potential, but lower than S. mutans .}, } @article {pmid35944318, year = {2022}, author = {Chen, J and Hai, Y and Zhang, W and Zhou, X}, title = {Insights into deterioration and reactivation of a mainstream anammox biofilm reactor response to C/N ratio.}, journal = {Journal of environmental management}, volume = {320}, number = {}, pages = {115780}, doi = {10.1016/j.jenvman.2022.115780}, pmid = {35944318}, issn = {1095-8630}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; Biofilms ; Bioreactors ; Carbon ; Denitrification ; Extracellular Polymeric Substance Matrix ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Wastewater/chemistry ; }, abstract = {In-depth knowledge of the deterioration and reactivation of the anaerobic ammonium oxidation (anammox) induced by carbon-to-nitrogen (C/N) is still lacking. Herein, the anammox performance was investigated in an anaerobic sequence biofilm batch reactor fed with low-strength partial nitration effluent in the range of C/N ratio from 0.5 to 3. The anammox was hardly deteriorated at C/N lower than 1.5, while became worsen if C/N was above 2.0. The specific anammox activity (SAA) experiments showed an 85% decrease of SAA at C/N of 3.0 compared with the maximum value (C/N:0). However, anammox capacity was rapidly recovered once influent C/N was adjusted back to zero. Moreover, C/N also highly affected the composition, structure and function of extracellular polymeric substance of the anammox biofilm. High-throughput sequencing revealed a close correlation between C/N change and microbial structure shift. Finally, the potential inhibition and restoration mechanism of the C/N-dependent anammox were proposed based on metagenomic analysis. This research provides some insights into the reinstatement of a mainstream anammox biofilm process after it is interrupted by high C/N influent.}, } @article {pmid35942584, year = {2022}, author = {Venturi, S and Crognale, S and Di Benedetto, F and Montegrossi, G and Casentini, B and Amalfitano, S and Baroni, T and Rossetti, S and Tassi, F and Capecchiacci, F and Vaselli, O and Fazi, S}, title = {Interplay between abiotic and microbial biofilm-mediated processes for travertine formation: Insights from a thermal spring (Piscine Carletti, Viterbo, Italy).}, journal = {Geobiology}, volume = {20}, number = {6}, pages = {837-856}, doi = {10.1111/gbi.12516}, pmid = {35942584}, issn = {1472-4669}, mesh = {Allyl Compounds ; Bacteria/metabolism ; Biofilms ; Calcium Carbonate/chemistry ; Calcium Sulfate/chemistry ; Carbon Dioxide/metabolism ; *Hot Springs/microbiology ; Minerals/metabolism ; Sulfides ; Sulfur/metabolism ; }, abstract = {Active hydrothermal travertine systems are ideal environments to investigate how abiotic and biotic processes affect mineralization mechanisms and mineral fabric formation. In this study, a biogeochemical characterization of waters, dissolved gases, and microbial mats was performed together with a mineralogical investigation on travertine encrustations occurring at the outflow channel of a thermal spring. The comprehensive model, compiled by means of TOUGHREACT computational tool from measured parameters, revealed that mineral phases were differently influenced by either abiotic conditions or microbially driven processes. Microbial mats are shaped by light availability and temperature gradient of waters flowing along the channel. Mineralogical features were homogeneous throughout the system, with euhedral calcite crystals, related to inorganic precipitation induced by CO2 degassing, and calcite shrubs associated with organomineralization processes, thus indicating an indirect microbial participation to the mineral deposition (microbially influenced calcite). The microbial activity played a role in driving calcite redissolution processes, resulting in circular pits on calcite crystal surfaces possibly related to the metabolic activity of sulfur-oxidizing bacteria found at a high relative abundance within the biofilm community. Sulfur oxidation might also explain the occurrence of gypsum crystals embedded in microbial mats, since gypsum precipitation could be induced by a local increase in sulfate concentration mediated by S-oxidizing bacteria, regardless of the overall undersaturated environmental conditions. Moreover, the absence of gypsum dissolution suggested the capability of microbial biofilm in modulating the mobility of chemical species by providing a protective envelope on gypsum crystals.}, } @article {pmid35942315, year = {2022}, author = {Dmitrijs, F and Guo, J and Huang, Y and Liu, Y and Fang, X and Jiang, K and Zha, L and Cai, J and Fu, X}, title = {Bacterial Succession in Microbial Biofilm as a Potential Indicator for Postmortem Submersion Interval Estimation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {951707}, pmid = {35942315}, issn = {1664-302X}, abstract = {Bacteria acts as the main decomposer during the process of biodegradation by microbial communities in the ecosystem. Numerous studies have revealed the bacterial succession patterns during carcass decomposition in the terrestrial setting. The machine learning algorithm-generated models based on such temporal succession patterns have been developed for the postmortem interval (PMI) estimation. However, the bacterial succession that occurs on decomposing carcasses in the aquatic environment is poorly understood. In the forensic practice, the postmortem submersion interval (PMSI), which approximately equals to the PMI in most of the common drowning cases, has long been problematic to determine. In the present study, bacterial successions in the epinecrotic biofilm samples collected from the decomposing swine cadavers submerged in water were analyzed by sequencing the variable region 4 (V4) of 16S rDNA. The succession patterns between the repeated experimental settings were repeatable. Using the machine learning algorithm for establishing random forest (RF) models, the microbial community succession patterns in the epinecrotic biofilm samples taken during the 56-day winter trial and 21-day summer trial were determined to be used as the PMSI predictors with the mean absolute error (MAE) of 17.87 ± 2.48 ADD (≈1.3 day) and 20.59 ± 4.89 ADD (≈0.7 day), respectively. Significant differences were observed between the seasons and between the substrates. The data presented in this research suggested that the influences of the environmental factors and the aquatic bacterioplankton on succession patterns of the biofilm bacteria were of great significance. The related mechanisms of such influence need to be further studied and clarified in depth to consider epinecrotic biofilm as a reliable predictor in the forensic investigations.}, } @article {pmid35941628, year = {2022}, author = {Wiriyasatiankun, P and Sakoolnamarka, R and Thanyasrisung, P}, title = {The impact of an alkasite restorative material on the pH of Streptococcus mutans biofilm and dentin remineralization: an in vitro study.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {334}, pmid = {35941628}, issn = {1472-6831}, mesh = {Biofilms ; Calcium ; Dental Materials ; Dentin ; *Fluorides/pharmacology ; Humans ; Hydrogen-Ion Concentration ; Hydroxides/pharmacology ; *Streptococcus mutans ; }, abstract = {BACKGROUND: It has been claimed that an alkasite restorative material can neutralize acids produced by cariogenic bacteria from released hydrogen ions and enable to remineralization via calcium and fluoride ions. However, there is no evidence to support this assertion. Therefore, the aims of this study were to investigate the effect of the alkasite restorative material on the pH of Streptococcus mutans biofilm and dentin hardness.

METHODS: Streptococcus mutans biofilms were formed on Filtek™ Z350 (FZ, a resin composite) and Cention® N (CN, the alkasite restorative material) and their pH determined after 24 h. Hydroxide, fluoride, and calcium-ions released from the materials were determined at 6 h, 1, 3, 7, 14, and 28 days. Dentin specimens were prepared from 14 human molars and divided into four quadrants. Quadrant 1 was a sound dentin control, quadrants 2-4 were chemically demineralized, and a cylinder of FZ and CN placed on the surfaces of quadrants 2 and 4, respectively. The microhardness of quadrants 1 and 3 were measured at depths of 20, 40, and 60 µm from the occlusal surface, and similarly of quadrants 2 and 4, after 30 days. Independent t-test, Mann-Whitney-U, and repeated-measure-ANOVA were used for data analysis.

RESULTS: The pH of biofilm on CN (4.45) was significantly higher (p < 0.05) than that on FZ (4.06). The quantity of all ions released from CN was significantly higher than from FZ. The hardness of demineralized dentin under CN was significantly higher than that of demineralized dentin at all depths, and higher than that of demineralized dentin under FZ at 20 and 40 µm.

CONCLUSIONS: CN released hydroxide, fluoride, and calcium ions, which was associated with raising the biofilm pH and the hardness of demineralized dentin. All results indicated that CN had the potential to reduce the incidence of secondary caries.}, } @article {pmid35941061, year = {2022}, author = {Xu, A and Wozniak, DJ and Zhou, J and Jiang, M and Dong, W}, title = {Toward a unified nomenclature for strains with hyper-biofilm phenotypes.}, journal = {Trends in microbiology}, volume = {30}, number = {11}, pages = {1019-1021}, doi = {10.1016/j.tim.2022.07.007}, pmid = {35941061}, issn = {1878-4380}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; }, mesh = {*Bacteria/genetics ; *Biofilms ; Phenotype ; }, abstract = {Hyper-biofilm strains form robust biofilms, are highly adaptable, and form highly tolerant subpopulations in biofilms grown in vivo and in vitro. Such subpopulations are formed by a wide range of bacteria and thus have been given different names in different species. This situation calls for the establishment of a unified nomenclature for strains with hyper-biofilm phenotypes.}, } @article {pmid35940753, year = {2022}, author = {Ma, Y and Zohaib Aslam, M and Wu, M and Nitin, N and Sun, G}, title = {Strategies and perspectives of developing anti-biofilm materials for improved food safety.}, journal = {Food research international (Ottawa, Ont.)}, volume = {159}, number = {}, pages = {111543}, doi = {10.1016/j.foodres.2022.111543}, pmid = {35940753}, issn = {1873-7145}, mesh = {*Biofilms ; *Food Safety ; }, abstract = {Foodborne diseases caused by ingesting pathogen-contaminated foods have become a significant global challenge afflicting public health. A report from the National Institute of Health found that around 80% of microbial infections were related to the generation of microbial biofilms on food-contact surfaces. Therefore, developing a universally applicable food-contact surface with an effective antibiofilm function is urgently needed. However, many antibiofilm strategies are designed for marine and medical industries, which are not fully applicable to the food area. Therefore, in this review, a comprehensive overview of the reported antibiofilm strategies originally designed for various applications is presented. According to their working mechanisms, these antibiofilm strategies were divided into "attack", "defense", and a combination of both. In addition, definitions, antibiofilm mechanisms, features, inherent limitations, and suitable application scenarios of typical antibiofilm strategies were systematically summarized, respectively, which could provide some underlying principles and perspectives to design food-contact surfaces with desirable antibiofilm functions in the future.}, } @article {pmid35940415, year = {2022}, author = {Jiang, Z and An, N and Chu, Y and Cao, B and Wu, F and Zhang, Y and Zhang, Y and Li, Y and Zhang, Y}, title = {Growth, biofilm formation and atrazine degrading gene (trzN) expression of Arthrobacter sp. DNS10 cultured with montmorillonite, kaolinite and goethite.}, journal = {Chemosphere}, volume = {307}, number = {Pt 2}, pages = {135904}, doi = {10.1016/j.chemosphere.2022.135904}, pmid = {35940415}, issn = {1879-1298}, mesh = {*Arthrobacter/genetics/metabolism ; *Atrazine/analysis ; Bentonite/chemistry ; Biofilms ; Iron Compounds ; Kaolin/chemistry ; Minerals/chemistry ; Reactive Oxygen Species/metabolism ; Soil/chemistry ; *Soil Pollutants/analysis ; }, abstract = {The viable and degradation potential of the strains which adhered to soil minerals are essential for eliminating organic pollutants from soil. Herein, the interaction (growth, biofilm formation and survive) of Arthrobacter sp. DNS10, an atrazine degrading strain, with three kinds of typical soil minerals, such as montmorillonite, kaolinite and goethite, as well as the atrazine degradation gene (trzN) expression of the strain in the minerals system were studied. The results showed that montmorillonite had significant promotion effect on the growth of strain DNS10, followed by kaolinite, but goethite significantly inhibited the growth of strain DNS10. In contrast, goethite notably promoted the biofilm formation and there was less biofilm detected in montmorillonite containing system. The percentage of the survival bacteria in the biofilm that formed on montmorillonite, kaolinite and goethite was 53.8%, 40.8% and 28.2%. In addition, there were more reactive oxygen species (ROS) were detected in the cells that exposed to goethite than those of the cells exposed to kaolinite and montmorillonite. These results suggest that the electrostatic repulsion between kaolinite/montmorillonite and strain DNS10 prevents them from contacting each other and facilitates bacterial growth by allowing the strain to obtain more nutrients. Oppositely, the needle-like morphology of goethite might damage the strain DNS10 cell when they were combined by electrostatic attraction, and the goethite induced ROS also aggravate the cytotoxicity of goethite on strain DNS10. In addition, the relative transcription of trzN in the cells contacted with montmorillonite, kaolinite and goethite was 0.94-, 0.27- and 0.20- fold of the no mineral exposure treatment. Briefly, this research suggests that the minerals with different structure and/or physicochemical characteristics might cause various trend for the biofilm formation and degradation potential of the bacteria.}, } @article {pmid35940405, year = {2022}, author = {Zhao, W and Bai, M}, title = {Upgrading integrated fixed-biofilm activated sludge (IFAS) system into separated two-sludge denitrifying phosphorus removal system: Nutrient removal and microbial structure.}, journal = {Chemosphere}, volume = {307}, number = {Pt 3}, pages = {135918}, doi = {10.1016/j.chemosphere.2022.135918}, pmid = {35940405}, issn = {1879-1298}, mesh = {Bacteria ; Biofilms ; Bioreactors/microbiology ; Carbon ; Denitrification ; Nitrogen/analysis ; Nutrients ; *Phosphorus ; *Sewage/microbiology ; Tin ; Waste Disposal, Fluid/methods ; }, abstract = {An integrated fixed-biofilm activated sludge (IFAS) system was upgraded into a separated two-sludge denitrifying phosphorus removal system to treat domestic sewage with a low carbon/nitrogen ratio (C/N = 3.6). The system was operated in IFAS mode for 135 days and then converted to the separated two-sludge mode to perform denitrifying phosphorus removal for 110 days. With denitrification and phosphorus removal conducted using "single carbon source", the experimental results show that the total inorganic nitrogen (TIN) and phosphorus (P) removal efficiencies were improved by 13.4% and 36.5%, respectively. As the activated sludge unit and biofilm unit were separated, Dechloromonas (4.10%) and Candidatus Accumulibacter (1.56%) were enriched in activated sludge system, while the nitrifiers Nitrospira and Nitrosomonas occupied the biofilm with proportions of 19.6% and 5.68%, respectively. The separated two-sludge denitrifying phosphorus removal system was characterized by higher nutrient removal and functional bacteria enrichment.}, } @article {pmid35940306, year = {2022}, author = {Ramakrishnan, R and Singh, AK and Singh, S and Chakravortty, D and Das, D}, title = {Enzymatic dispersion of biofilms: An emerging biocatalytic avenue to combat biofilm-mediated microbial infections.}, journal = {The Journal of biological chemistry}, volume = {298}, number = {9}, pages = {102352}, pmid = {35940306}, issn = {1083-351X}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; Bacteria ; *Biofilms ; Polysaccharides ; }, abstract = {Drug resistance by pathogenic microbes has emerged as a matter of great concern to mankind. Microorganisms such as bacteria and fungi employ multiple defense mechanisms against drugs and the host immune system. A major line of microbial defense is the biofilm, which comprises extracellular polymeric substances that are produced by the population of microorganisms. Around 80% of chronic bacterial infections are associated with biofilms. The presence of biofilms can increase the necessity of doses of certain antibiotics up to 1000-fold to combat infection. Thus, there is an urgent need for strategies to eradicate biofilms. Although a few physicochemical methods have been developed to prevent and treat biofilms, these methods have poor efficacy and biocompatibility. In this review, we discuss the existing strategies to combat biofilms and their challenges. Subsequently, we spotlight the potential of enzymes, in particular, polysaccharide degrading enzymes, for biofilm dispersion, which might lead to facile antimicrobial treatment of biofilm-associated infections.}, } @article {pmid35940002, year = {2022}, author = {Xiao, S and Shang, K and Zhang, L and Li, W and Wang, X}, title = {A rapid anti-Helicobacter pylori biofilm drug screening biosensor based on AlpB outer membrane protein and colloidal gold/nanoporous gold framework.}, journal = {Biosensors & bioelectronics}, volume = {215}, number = {}, pages = {114599}, doi = {10.1016/j.bios.2022.114599}, pmid = {35940002}, issn = {1873-4235}, mesh = {Bacterial Outer Membrane Proteins/*metabolism ; Biofilms ; *Biosensing Techniques ; *Curcumin/pharmacology ; Drug Evaluation, Preclinical ; Erythromycin ; Gold Colloid ; *Helicobacter Infections ; *Helicobacter pylori ; Humans ; Membrane Proteins ; Molecular Docking Simulation ; *Nanopores ; Rifampin/pharmacology ; }, abstract = {Inhibition or disruption of biofilms has been recognized as an important means to eradicate Helicobacter pylori (H. pylori) infection. However, a fast and efficient drug screening method against H. pylori biofilms has not yet been established. Therefore, AlpB, an important outer membrane protein in H. pylori biofilm formation, was selected as a biological recognition element to screen anti-biofilm drugs in this study. A novel AlpB/colloidal gold (CG)/nanoporous gold (NPG)/Nafion-reduced graphene oxide (rGO)/glassy carbon electrode (GCE) biosensor was constructed based on the heterologous expression of AlpB. The prepared AlpB-based biosensor not only successfully identified six anti-biofilm drugs, but also evaluated the sensitivity and action intensity of different anti-biofilm drugs binding to AlpB by interaction kinetics analysis. The sensitivity order of AlpB to the six anti-biofilm drugs was: allicin > erythromycin > SCC > curcumin > rifampicin > NAC and the action intensity of the six anti-biofilm drugs on AlpB was: rifampicin > NAC > allicin > erythromycin > SCC > curcumin. In addition, molecular docking results showed that the six anti-biofilm drugs might exert their anti-biofilm effects by spontaneously binding to the conserved region of AlpB protein. This study provided a rapid screening platform and a unified data processing method for potential anti-biofilm drug development.}, } @article {pmid35938806, year = {2022}, author = {Stokas, H and Rhodes, HL and Simmons, MB and Zhang, R and Wright, CC and Purdy, GE}, title = {M. tuberculosis AlkX Encoded by rv3249c Regulates a Conserved Alkane Hydroxylase System That Is Important for Replication in Macrophages and Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0196922}, pmid = {35938806}, issn = {2165-0497}, support = {R01 AI123148/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics ; Biofilms ; Cytochrome P-450 CYP4A/genetics/metabolism ; Humans ; Macrophages/microbiology ; *Mycobacterium tuberculosis/metabolism ; Rubredoxins/genetics ; *Tuberculosis/microbiology ; }, abstract = {Mycobacterium tuberculosis is a highly specialized human pathogen. The success of M. tuberculosis is due to its ability to replicate within host macrophages, resist host immune responses, and ultimately enter a persistent state during a latent tuberculosis infection. Understanding how M. tuberculosis adapts to and replicates in the intracellular environment of the host is crucial for the development of novel, targeted therapeutics. We report the characterization of an M. tuberculosis mutant lacking Rv3249c, a TetR transcriptional regulator. We show that Rv3249c directly represses the adjacent alkB-rubA-rubB operon encoding an alkane hydroxylase/rubredoxin system. For consistency with related systems, we have named the rv3249c gene alkX. The alkX mutant survived better than wild-type M. tuberculosis inside macrophages. This could be phenocopied by overexpression of the alkB-rubA-rubB locus. We hypothesized that the improved intracellular survival phenotype is a result of increased fitness of the mutant; however, we found that the alkX mutant had a defect when grown on some host-associated carbon sources in vitro. We also found that the alkX mutant had a defect in biofilm formation, also linked to the overexpression of the alkB-rubAB genes. Combined, these results define the primary role of AlkX as a transcriptional repressor of the alkB-rubAB operon and suggest the operon contributes to intracellular survival of the pathogen. IMPORTANCE Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is the leading cause of death worldwide due to a single infectious agent. It is important to understand how M. tuberculosis adapts to and replicates in the intracellular environment of the host. In this study, we characterized the TetR transcriptional regulator Rv3249c and show that it regulates a highly conserved alkane hydroxylase/rubredoxin system. Our data demonstrate that the AlkBRubAB system contributes to the success of the bacterium in host macrophages.}, } @article {pmid35938693, year = {2022}, author = {Faveri, M and Lamunier, L and de Figueiredo, LC and Meza-Mauricio, J and Scombatti de Souza, SL and Bueno-Silva, B}, title = {In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm.}, journal = {Biofouling}, volume = {38}, number = {6}, pages = {656-662}, doi = {10.1080/08927014.2022.2070431}, pmid = {35938693}, issn = {1029-2454}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; DNA ; *Dental Implants ; Surface Properties ; Titanium/pharmacology ; }, abstract = {Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes-conventional and Anodization-were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA-DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.}, } @article {pmid35936523, year = {2022}, author = {Alikhani, T and Daie Ghazvini, R and Mirzaii, M and Hashemi, SJ and Fazli, M and Rafat, Z and Roostaei, D and Ardi, P and Kamali Sarvestani, H and Zareei, M}, title = {Drug Resistance and Biofilm Formation in Candida Species of Vaginal Origin.}, journal = {Iranian journal of public health}, volume = {51}, number = {4}, pages = {913-918}, pmid = {35936523}, issn = {2251-6093}, abstract = {BACKGROUND: Candida species are normal vaginal flora in healthy women, which can cause vulvovaginal candid-iasis (VVC). The formation of biofilm is a cause of drug resistance in Candida species of vaginal origin. We aimed to specify Candida species cause VVC, detect their biofilm-forming ability, and antifungal susceptibility pattern.

METHODS: Overall 150 vaginal samples were collected from suspected cases of referring to Bahar Hospital of Shahroud, Iran between Jan 2018 and Jan 2019. Samples were cultured on Sabouraud dextrose agar (SDA), Chrome gar Candida and Corn meal agar (CMA). PCR-RFLP was performed to confirm the identification. Bio-film formation of the identified species was measured by the Crystal Violet method. The susceptibility to fluconazole, clotrimazole, and miconazole was determined based on the CLSI document M27-A3.

RESULTS: Of 50 women (33.3%) were suffering from VVC. C.albicans was the predominant species isolated in this study (n=39, 78%) followed by C. glabratia (n=11, 22%). In addition, in 25 (50%) of positive samples, bio-film formation was determined. The mean MIC of fluconazole and clotrimazole for C. albicans was 5.02 μg/mL and 3.92 μg/mL, respectively. Furthermore, the mean MIC related to these drugs for C. glabrata was 12.45 μg / mL and 4.1μg / mL, respectively. The mean diameter of miconazole inhibition zone for C. albicans and C. glabra isolates was 25.13 mm and 24.5mm, respectively and all of them were susceptible to this drug.

CONCLUSION: C.albicans was the predominant Candida species isolated from patients with VVC and also was the predominant biofilm producer species.}, } @article {pmid35935227, year = {2022}, author = {Hao, X and Yan, W and Yang, J and Bai, Y and Qian, H and Lou, Y and Ju, P and Zhang, D}, title = {Matrine@chitosan-D-proline nanocapsules as antifouling agents with antibacterial properties and biofilm dispersibility in the marine environment.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {950039}, pmid = {35935227}, issn = {1664-302X}, abstract = {Antifoulants are the most vital substances in antifouling coatings to prevent marine organisms from colonizing the undersea substrate surfaces. In addition to antibacterial performance, inhibition of biofilm formation is an important criterion for antifouling coatings. In this study, we synthesized pH-responsive matrine@chitosan-D-proline (Mat@CS-Pro) nanocapsules of about 280 nm with antibacterial properties and biofilm dispersibility. The prepared Mat@CS-Pro nanocapsules exhibited high-level antibacterial properties, reaching about 93, 88, and 96% for E. coli, S. aureus, and P. aeruginosa, respectively. Such nanocapsules can cause irreversible damage to bacteria and cause them to lose their intact cell structures. Moreover, Mat@CS-Pro nanocapsules also possessed outstanding dispersal biofilm performances, in which the biofilm thickness of E. coli, S. aureus, and P. aeruginosa was decreased by 33, 74, and 42%, respectively, after 3 days of incubation. Besides, the Mat@CS-Pro nanocapsules had remarkable pH-responsive properties. As the environmental pH became acidic, the nanocapsules swelled to about 475 nm and the released concentration could reach 28.5 ppm after immersion for 10 h but maintained a low releasing rate in pH 8 conditions.}, } @article {pmid35935146, year = {2022}, author = {Dhall, A and Ramjee, R and Oh, MJ and Tao, K and Hwang, G}, title = {A 3D-Printed Customizable Platform for Multiplex Dynamic Biofilm Studies.}, journal = {Advanced materials technologies}, volume = {7}, number = {7}, pages = {}, pmid = {35935146}, issn = {2365-709X}, support = {R01 DE027970/DE/NIDCR NIH HHS/United States ; }, abstract = {Biofilms are communities of microbes that colonize surfaces. While several biofilm experimental models exist, they often have limited replications of spatiotemporal dynamics surrounding biofilms. For a better understanding dynamic and complex biofilm development, this manuscript presents a customizable platform compatible with off-the-shelf well plates that can monitor microbial adhesion, growth, and associated parameters under various relevant scenarios by taking advantage of 3D printing. The system i) holds any substrate in a stable, vertical position, ii) subjects samples to flow at different angles, iii) switches between static and dynamic modes during an experiment, and iv) allows multiplexing and real-time monitoring of biofilm parameters. Simulated fluid dynamics is employed to estimate flow patterns around discs and shear stresses at disc surfaces. A 3D printed peristaltic pump and a customized pH measurement system for real-time tracking of spent biofilm culture media are equipped with a graphical user interface that grants control over all experimental parameters. The system is tested under static and dynamic conditions with Streptococcus mutans using different carbon sources. By monitoring the effluent pH and characterizing biochemical, microbiological, and morphological properties of cultured biofilms, distinct properties are demonstrated. This novel platform liberates designing experimental strategies for investigations of biofilms under various conditions.}, } @article {pmid35935044, year = {2022}, author = {Ghoreishi, FS and Roghanian, R and Emtiazi, G}, title = {Novel Chronic Wound Healing by Anti-biofilm Peptides and Protease.}, journal = {Advanced pharmaceutical bulletin}, volume = {12}, number = {3}, pages = {424-436}, pmid = {35935044}, issn = {2228-5881}, abstract = {Chronic wounds have made a challenge in medical healthcare due to their biofilm infections, which reduce the penetrance of the antibacterial agents in the injury site. In infected wounds, the most common bacterial strains are Staphylococcus aureus and Pseudomonas aeruginosa. Biofilm disruption in chronic wounds is crucial in wound healing. Due to their broad-spectrum antibacterial properties and fewer side effects, anti-biofilm peptides, especially bacteriocins, are promising in the healing of chronic wounds by biofilm destruction. This study reviews the effects of antimicrobial and anti-biofilm agents, including bacteriocins and protease enzymes as a novel approach, on wound healing, along with analyzing the molecular docking between a bacterial protease and biofilm components. Among a large number of anti-biofilm bacteriocins identified up to now, seven types have been registered in the antimicrobial peptides (AMPs) database. Although it is believed that bacterial proteases are harmful in wound healing, it has recently been demonstrated that these proteases like the human serine protease, in combination with AMPs, can improve wound healing by biofilm destruction. In this work, docking results between metalloprotease from Paenibacillus polymyxa and proteins of S. aureus and P. aeruginosa involved in biofilm production, showed that this bacterial protease could efficiently interact with biofilm components. Infected wound healing is an important challenge in clinical trials due to biofilm production by bacterial pathogens. Therefore, simultaneous use of proteases or anti-biofilm peptides with antimicrobial agents could be a promising method for chronic wound healing.}, } @article {pmid35934630, year = {2022}, author = {Xia, A and Chen, H and Huang, Y and Zhu, X and Liao, Q}, title = {Mathematical modeling of intercellular interactions within the biofilm.}, journal = {Trends in microbiology}, volume = {30}, number = {10}, pages = {925-929}, doi = {10.1016/j.tim.2022.07.005}, pmid = {35934630}, issn = {1878-4380}, mesh = {*Bacteria/genetics ; *Biofilms ; Models, Theoretical ; }, abstract = {Bacteria accumulate and are embedded in a self-produced matrix, forming the biofilm. The interactions among cells drive the development of biofilms and provide properties that differ from planktonic cells. This forum article focuses on how intercellular mechanical interactions and physiological behaviors lead to community-scale features via exploring the applicability of biofilm mathematical models.}, } @article {pmid35934203, year = {2022}, author = {Banerjee, A and Pal, S and Goswami, P and Batabyal, K and Joardar, SN and Dey, S and Isore, DP and Dutta, TK and Bandyopadhyay, S and Samanta, I}, title = {Docking analysis of circulating CTX-M variants in multi-drug resistant, beta-lactamase and biofilm-producing E. coli isolated from pet animals and backyard livestock.}, journal = {Microbial pathogenesis}, volume = {170}, number = {}, pages = {105700}, doi = {10.1016/j.micpath.2022.105700}, pmid = {35934203}, issn = {1096-1208}, mesh = {Ampicillin ; Animals ; Anti-Bacterial Agents/metabolism/pharmacology ; Biofilms ; Cefotaxime ; Dogs ; *Escherichia coli/metabolism ; *Escherichia coli Infections/microbiology ; Humans ; Livestock ; Molecular Docking Simulation ; Phylogeny ; Sheep ; beta-Lactam Resistance ; beta-Lactamases/genetics/metabolism ; }, abstract = {The generation of antimicrobial-resistant bacteria largely depends on the use of antimicrobials not only in humans but also in pet animals and livestock. The present study was conducted to detect the occurrence of beta-lactamase and biofilm-producing- E.coli in healthy pet and backyard livestock. The study also intended on molecular docking experiments to confirm the nature of the catalytic mechanism in β-lactamase enzymes, encoded by the various blaCTX-M genotypes and phylogenetic analysis to reveal clonal relationship of the animal origin E. coli isolates with human clinical strains. The rectal swabs were collected from healthy dogs (n = 254), cats (n = 108), sheep (n = 119) and goats (n = 143) in India. In total 247 (76.47%) E. coli strains were identified as ESBL producers. The possession of ESBL-producers was significantly more (p < 0.05) in pets than in the backyard livestock. Most of the strains possessed blaCTX-M-15 like clones. E. coli strains possessing blaCTX-M-15.2, blaCTX-M-157, blaCTX-M-181 and blaCTX-M-218 like clones, isolated from pets were not reported earlier. The study detected 56.65% of E. coli strains as moderate or strong biofilm producers possessing biofilm-associated genes (csgA, rcsA, rpoS, sdiA). ESBL-producing E. coli showed phenotypical resistance to tetracycline (93.1%), azithromycin (89.8%), ampicillin (84.2%), cefotaxime (80.9%), doxycycline (82.5%), co-trimoxazole (80.9%), ampicillin/cloxacillin (76.9%). The CTX-M variants obtained in this study were modelled by the SWISS-MODEL and verified. Ligand having minimum binding energy, show the highest affinity of β-lactamases for cefotaxime and cefpodoxime. The Gibbs free energy release for all 14 different complex ranges between -6.9 (CTX-M-15.2+cefpodoxime) to -5.3 (CTX-M-218+cefpodoxime) Kcal/mol. Phylogenetic analysis of the animal origin ESBL-E. coli strains revealed a partial clonal relationship with the clinical isolates of local human patients. The present study described the significant presence of biofilm and β-lactamase producing, multi-drug resistant E. coli in pet animals having public health importance.}, } @article {pmid35934149, year = {2022}, author = {Di Pippo, F and Crognale, S and Levantesi, C and Vitanza, L and Sighicelli, M and Pietrelli, L and Di Vito, S and Amalfitano, S and Rossetti, S}, title = {Plastisphere in lake waters: Microbial diversity, biofilm structure, and potential implications for freshwater ecosystems.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {310}, number = {}, pages = {119876}, doi = {10.1016/j.envpol.2022.119876}, pmid = {35934149}, issn = {1873-6424}, mesh = {Biofilms ; Eukaryota ; Lakes ; *Microbiota ; *Plastics ; Spectroscopy, Fourier Transform Infrared ; Water ; }, abstract = {Once dispersed in water, microplastic (MP) particles are rapidly colonised by aquatic microbes, which can adhere and grow onto solid surfaces in the form of biofilms. This study provides new insights on microbial diversity and biofilm structure of plastisphere in lake waters. By combining Fourier Confocal Laser Scanning Microscopy (CLSM), Transform Infrared Spectroscopy (FT-IR) and high-throughput DNA sequencing, we investigated the microbial colonization patterns on floating MPs and, for the first time, the occurrence of eukaryotic core members and their possible relations with biofilm-forming bacterial taxa within the plastisphere of four different lakes. Through PCR-based methods (qPCR, LAMP-PCR), we also evaluated the role of lake plastisphere as long-term dispersal vectors of potentially harmful organisms (including pathogens) and antibiotic resistance genes (ARGs) in freshwater ecosystems. Consistent variation patterns of the microbial community composition occurred between water and among the plastisphere samples of the different lakes. The eukaryotic core microbiome was mainly composed by typical freshwater biofilm colonizers, such as diatoms (Pennales, Bacillariophyceaea) and green algae (Chlorophyceae), which interact with eukaryotic and prokaryotic microbes of different trophic levels. Results also showed that MPs are suitable vectors of biofilm-forming opportunistic pathogens and a hotspot for horizontal gene transfer, likely facilitating antibiotic resistance spread in the environments.}, } @article {pmid35933874, year = {2022}, author = {Soo, PL and Bashir, MJK and Wong, LP}, title = {Recent advancements in the treatment of palm oil mill effluent (POME) using anaerobic biofilm reactors: Challenges and future perspectives.}, journal = {Journal of environmental management}, volume = {320}, number = {}, pages = {115750}, doi = {10.1016/j.jenvman.2022.115750}, pmid = {35933874}, issn = {1095-8630}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Industrial Waste ; Palm Oil ; *Plant Oils ; Waste Disposal, Fluid/methods ; }, abstract = {Palm oil is the most utilized vegetable globally which is mostly produced in countries such as Malaysia, Indonesia and Thailand. The great amount of POME generation from palm oil mills is now a threat to the environment and require a suitable treatment of POME to reduce the organic strength in accordance with the standard discharge limit before releasing to the environment. Currently, the technology to combine the anaerobic process and biofilm system in bioreactors have produced a fresh idea in treatments of high strength wastewater like POME. Anaerobic biofilm reactor is a convincing method for POME treatment due to its significant advantages over the conventional biological treatments consisting of anaerobic, aerobic and facultative pond systems. Overall, integrated anaerobic-aerobic bioreactor (IAAB) can remove more than 99% of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) with the combination of anaerobic and aerobic digestion for POME treatment. It has better performance as compared to up-flow anaerobic sludge blanket (UASB) and up-flow anaerobic filter (UAF) with 80% and 88-94% COD removal efficiency respectively. Anaerobic pond was found to perform well also by removing 97.8% of COD in POME but require long retention time and larger land. Hence, this study aims to provide intensive review of the performance of the anaerobic biofilm reactor in treating POME and the recent advancements in this technology. The limitations and future perspectives in utilization of anaerobic biofilm reactor during its operation in treating POME are discussed.}, } @article {pmid35933363, year = {2022}, author = {Moris, V and Lam, M and Amoureux, L and Magallon, A and Guilloteau, A and Maldiney, T and Zwetyenga, N and Falentin-Daudre, C and Neuwirth, C}, title = {What is the best technic to dislodge Staphylococcus epidermidis biofilm on medical implants?.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {192}, pmid = {35933363}, issn = {1471-2180}, mesh = {*Biofilms ; Humans ; Silicones ; Sonication ; *Staphylococcus epidermidis ; }, abstract = {BACKGROUND: Bacterial biofilm can occur on all medical implanted devices and lead to infection and/or dysfunction of the device. In this study, artificial biofilm was formed on four different medical implants (silicone, piccline, peripheral venous catheter and endotracheal tube) of interest for our daily clinical and/or research practice. We investigated the best conventional technic to dislodge the biofilm on the implants and quantified the number of bacteria. Staphylococcus epidermidis previously isolated from a breast implant capsular contracture on a patient in the university hospital of Dijon was selected for its ability to produce biofilm on the implants. Different technics (sonication, Digest-EUR®, mechanized bead mill, combination of sonication plus Digest-EUR®) were tested and compared to detach the biofilm before quantifying viable bacteria by colony counting.

RESULTS: For all treatments, the optical and scanning electron microscope images showed substantial less biofilm biomass remaining on the silicone implant compared to non-treated implant. This study demonstrated that the US procedure was statistically superior to the other physical treatment: beads, Digest-EUR® alone and Digest-EUR® + US (p < 0.001) for the flexible materials (picc-line, PIV, and silicone). The number of bacteria released by the US is significantly higher with a difference of 1 log on each material. The result for a rigid endotracheal tube were different with superiority for the chemical treatment dithiothreitol: Digest-EUR®. Surprisingly the combination of the US plus Digest-EUR® treatment was consistently inferior for the four materials.

CONCLUSIONS: Depending on the materials used, the biofilm dislodging technique must be adapted. The US procedure was the best technic to dislodge S. epidermidis biofilm on silicone, piccline, peripheral venous catheter but not endotracheal tube. This suggested that scientists should compare themselves different methods before designing a protocol of biofilm study on a given material.}, } @article {pmid35933078, year = {2022}, author = {Milton, AAP and Momin, AG and Gandhale, PN and Das, S and Ghatak, S and Priya, GB and Firake, DM and Srinivas, K and Momin, KM and Hussain, Z and Sen, A}, title = {Prevalence, toxinotyping, antimicrobial susceptibility and biofilm-forming ability of Clostridium perfringens isolated from free-living rodents and shrews.}, journal = {Anaerobe}, volume = {77}, number = {}, pages = {102618}, doi = {10.1016/j.anaerobe.2022.102618}, pmid = {35933078}, issn = {1095-8274}, mesh = {Mice ; Rats ; Animals ; Humans ; *Shrews/microbiology ; Clostridium perfringens/genetics ; Prevalence ; Biofilms ; Murinae ; *Clostridium Infections/epidemiology/veterinary/microbiology ; }, abstract = {BACKGROUND AND OBJECTIVES: Clostridium perfringens (C. perfringens), is a spore-forming and toxin-producing pathogenic Gram-positive rod-shaped bacterium with immense public health/zoonotic concern. Rodents are well-known reservoirs and vectors for a large number of zoonoses and strong links have been recognized between synanthropic rodents and foodborne disease outbreaks throughout the world. To date, no study has been conducted for studying the prevalence of C. perfringens in rodents and shrews. In this study, we investigated faecal samples from free-living rodents and shrews trapped in Meghalaya, a North-eastern hill state of India for the presence of virulent and antimicrobial-resistant C. perfringens.

METHODS: A total of 122 animals comprising six species of rodents and one species of shrews were trapped: Mus musculus (n = 15), Mus booduga (n = 7), Rattus rattus (n = 9), Rattus norvegicus (n = 3), Bandicota indica (n = 30), Bandicota bengalensis (n = 32) and Suncus murinus (n = 26). The faecal swabs were collected and processed for the isolation of C. perfringens. Toxinotyping was done using PCR. Antimicrobial susceptibility testing and biofilm forming ability testing were done using Kirby Bauer disc diffusion method and crystal violet assay.

RESULTS: C. perfringens was isolated from 27 of the 122 faecal swabs (22.1%), from six species of rodents and shrews. Five of the host species were rodents, Bandicota bengalensis (25%), Bandicota indica (16.7%), Rattus norvegicus (33.3%), Mus musculus (13.3%), Mus booduga (42.8%) and Suncus murinus (shrew) (29.6%). The common toxinotype was type A (59.2%) followed by Type A with beta2 toxin (33.3%), Type C (3.7%) and Type C with beta2 toxin (3.7%). None of the isolates harboured cpe, etx, iap, and NetB genes and therefore none was typed as either B, D, E, F, or G. Nine isolates (33.3%) turned out to be multi-drug resistant (MDR), displaying resistance to three or more categories of antibiotics tested. Twenty-three out of twenty-seven isolates (85.2%) were forming biofilms.

CONCLUSION: Globally, this is the first study to report the prevalence of C. perfringens and its virulence profile and antimicrobial resistance in free-living rodents and shrews. The rodents and shrews can potentially contaminate the food and environment and can infect humans and livestock with multi-drug resistant/virulent Type A and Type C C. perfringens.}, } @article {pmid35932962, year = {2022}, author = {Pourhajibagher, M and Bahrami, R and Bahador, A}, title = {An ex vivo evaluation of physico-mechanical and anti-biofilm properties of resin-modified glass ionomer containing ultrasound waves-activated nanoparticles against Streptococcus mutans biofilm around orthodontic bands.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {40}, number = {}, pages = {103051}, doi = {10.1016/j.pdpdt.2022.103051}, pmid = {35932962}, issn = {1873-1597}, mesh = {Humans ; Streptococcus mutans ; Fluorides/pharmacology ; *Photochemotherapy/methods ; Glass Ionomer Cements/pharmacology/chemistry ; Adhesives ; Materials Testing ; *Orthodontic Brackets ; }, abstract = {BACKGROUND: The present study evaluated the physico-mechanical and antimicrobial properties of ultrasound waves-activated modified-resin glass ionomer containing nanosonosensitizers such as nano-curcumin (n-Cur), nano-emodin (n-Emo), and nano-quercetin (n-Qct) against Streptococcus mutans biofilm on the surface of modified-resin glass ionomer bonded orthodontic bands.

MATERIALS AND METHODS: A total of 50 human molar teeth were used in this study. The shear bond strength (SBS), adhesive remnant index (ARI), setting time, and fluoride release of modified orthodontics cement containing different concentrations of n-Cur, n-Emo, and n-Qct (0, 2, 5, and 10%) were measured. The antimicrobial effectiveness was assessed against S. mutans by the biofilm inhibition test, and the Log10 colony-forming unit (CFU)/mL was evaluated.

RESULTS: SBS and setting time of modified glass ionomer decreased compared with the control group. 5% n-Emo, 2% n-Qct, and 5% n-Cur were the highest concentrations that had an insignificant difference in comparison with Transbond XT (P = 0.647, 0.819, and 0.292, respectively). The groups were not significantly different in terms of ARI score (P > 0.05). The highest and lowest setting time belonged to the control and 5% n-Emo groups, respectively; this difference in setting time was significant (P < 0.05). Ultrasound waves and 0.2% CHX significantly reduced S. mutans biofilms compared with the control group (P < 0.001), and minimum S. mutans colony count was shown in 0.2% CHX and 5% n-Emo groups. The addition of nanosonosensitizers to the glass ionomer did not compromise the fluoride release of the glass ionomer.

CONCLUSION: It could be concluded that resin-modified glass ionomer containing ultrasound waves-activated 5% n-Emo reduces S. mutans biofilm around orthodontic bands with no adverse effect on SBS, ARI, and its application in the clinic.}, } @article {pmid35931282, year = {2022}, author = {Zhou, X and Bi, X and Yang, T and Fan, X and Shi, X and Wang, L and Zhang, Y and Cheng, L and Zhao, F and Maletskyi, Z and Hui, X}, title = {Metagenomic insights into microbial nitrogen metabolism in two-stage anoxic/oxic-moving bed biofilm reactor system with multiple chambers for municipal wastewater treatment.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127729}, doi = {10.1016/j.biortech.2022.127729}, pmid = {35931282}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Nitrification ; *Nitrogen/metabolism ; Sewage ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {To explore the microbial nitrogen metabolism of a two-stage anoxic/oxic (A/O)-moving bed biofilm reactor (MBBR), biofilms of the system's chambers were analyzed using metagenomic sequencing. Significant differences in microbial populations were found among the pre-anoxic, oxic and post-anoxic MBBRs (P < 0.01). Nitrospira and Nitrosomonas had positive correlations with ammonia nitrogen (NH4[+]-N) removal, and were also predominant in oxic MBBRs. These organisms were the hosts of functional genes for nitrification. The denitrifying genera were predominant in anoxic MBBRs, including Thiobacillus and Sulfurisoma in pre-anoxic MBBRs and Dechloromonas and Thauera in post-anoxic MBBRs. The four genera had positive correlations with total nitrate and nitrite nitrogen (NOX[-]-N) removal and were the hosts of functional genes for denitrification. Specific functional biofilms with different microbial nitrogen metabolisms were formed in each chamber of this system. This work provides a microbial theoretical support for the two-stage A/O-MBBR system.}, } @article {pmid35930881, year = {2022}, author = {Zhao, J and Ni, G and Piculell, M and Li, J and Hu, Z and Wang, Z and Guo, J and Yuan, Z and Zheng, M and Hu, S}, title = {Characterizing and comparing microbial community and biofilm structure in three nitrifying moving bed biofilm reactors.}, journal = {Journal of environmental management}, volume = {320}, number = {}, pages = {115883}, doi = {10.1016/j.jenvman.2022.115883}, pmid = {35930881}, issn = {1095-8630}, mesh = {Biofilms ; Biomass ; Bioreactors ; *Microbiota ; *Nitrification ; }, abstract = {This study investigated biofilm establishment, biofilm structure, and microbial community composition of biofilms in three laboratory-scale moving bed biofilm reactors. These reactors were filled with three types of plastic carriers with varied depths of living space for microbial growth. The reactors were operated under the same influent and operational conditions. Along with the operation, the results showed that carriers with grids of 50 μm in height delayed the biofilm development and formed the thinnest biofilm and a carpet-like structure with the lowest α-diversity. In comparison, another two carriers with grids of 200 and 400 μm in height formed thick biofilms and large colonies with more voids and channels. Quantified properties of biofilm thickness, biomass, heterogeneity, portion of the biofilm exposed to the nutrient, and maximum diffusion distance were examined, and the results demonstrated that they almost (except for heterogeneity) strongly correlated to the α-diversity of microbial community. These illustrate that depth of living space, as an important parameter for carrier, could drive the formation of biofilm structure and community composition. It improves understanding of influencing factors on biofilm establishment, structure and its microbial community, and would be helpful for the design of biofilm processes.}, } @article {pmid35929762, year = {2022}, author = {Yu, H and Xu, X and Xie, Z and Huang, X and Lin, L and Jiao, Y and Li, H}, title = {High-Efficiency Near-Infrared Light Responsive Antibacterial System for Synergistic Ablation of Bacteria and Biofilm.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {32}, pages = {36947-36956}, doi = {10.1021/acsami.2c08406}, pmid = {35929762}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Humans ; Infrared Rays ; *Zinc Oxide/pharmacology ; }, abstract = {Bacterial infection is seriously threatening human health, and the design of high-efficiency and good biocompatibility antibacterial agents is an urgent problem to be solved. However, with the emergence of drug-resistant bacteria, the existing antibacterial agents have low killing efficiency, and the formation of biofilms has further weakened the therapeutic effect. Herein, we constructed an efficient antibacterial system mediated by near-infrared light for synergistic antibacterial and biofilm dissipation. Specifically, the ZnO/Ti3C2Tx with heterojunction was synthesized by hydrothermal growth of ZnO on the surface of lamellar Ti3C2Tx-MXene. The prepared ZnO/Ti3C2Tx had better photothermal ability than ZnO and Ti3C2Tx, respectively. The local thermal effect can not only destroy the integrity of the bacterial membrane but also promote the release of Zn[2+] ions and further improve the antibacterial performance. ZnO/Ti3C2Tx achieved a 100% sterilization rate (better than either ZnO or Ti3C2Tx) at 150 μg mL[-1]. The biofilm dissipation experiment further proved its excellent biofilm ablation effect. More importantly, the results of in vitro cell culture and animal experiments have demonstrated its good biological safety. In summary, this new type of nanomaterial shows strong local chemical photothermal sterilization ability and has great potential to replace traditional antibacterial agents.}, } @article {pmid35929222, year = {2022}, author = {Hympanova, M and Oliver-Urrutia, C and Vojta, M and Macháček, M and Krupka, P and Kukla, R and Celko, L and Montufar, EB and Marek, J}, title = {Assessment of Streptococcus mutans biofilm formation on calcium phosphate ceramics: The role of crystalline composition and microstructure.}, journal = {Biomaterials advances}, volume = {135}, number = {}, pages = {212750}, doi = {10.1016/j.bioadv.2022.212750}, pmid = {35929222}, issn = {2772-9508}, mesh = {Biofilms ; *Calcium Phosphates/pharmacology ; Ceramics/pharmacology ; Durapatite/chemistry ; *Streptococcus mutans ; }, abstract = {Streptococcus mutans is one of the bacteria that initiates the colonization of the pellicle at the tooth surface. It forms a plaque, together with other bacteria, which gradually dissolves the pellicle and leaves the tooth surface unprotected against the acidic oral environment. Calcium phosphate ceramics are excellent synthetic materials for the study of biofilm formation in dentistry because they are comparable to teeth in chemical composition and structure. Calcium phosphates can be processed to achieve a variety of crystalline compounds with biologically relevant ionic substitutions and structures that allow study of the effect of the surface chemistry and the topography independently. In this article, we describe the preparation and characterization of three types of calcium phosphate-based materials as a suitable surface for the formation of the S. mutans biofilm: beta-tricalcium phosphate (β-TCP); sintered hydroxyapatite (SHA); and calcium-deficient hydroxyapatite (CDHA). The densest biofilms were formed on the surfaces of SHA and CDHA, with no significant differences due to the stoichiometry or microstructure. In contrast, β-TCP showed a lower susceptibility to S. mutans biofilm formation, suggesting that the crystalline structure is the controlling parameter. Subsequently, SHA was selected to develop a dental biofilm model that allowed study of S. mutans biofilm susceptibility to chlorhexidine and ethanol.}, } @article {pmid35928206, year = {2022}, author = {Alves-Barroco, C and Botelho, AMN and Américo, MA and Fracalanzza, SEL and de Matos, APA and Guimaraes, MA and Ferreira-Carvalho, BT and Figueiredo, AMS and Fernandes, AR}, title = {Assessing in vivo and in vitro biofilm development by Streptococcus dysgalactiae subsp. dysgalactiae using a murine model of catheter-associated biofilm and human keratinocyte cell.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {874694}, pmid = {35928206}, issn = {2235-2988}, mesh = {Animals ; Biofilms ; Catheters ; Cattle ; Disease Models, Animal ; Female ; Humans ; Keratinocytes ; *Mastitis, Bovine/microbiology ; Mice ; Streptococcus ; Zebrafish ; }, abstract = {Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) is an important agent of bovine mastitis. This infection causes an inflammatory reaction in udder tissue, being the most important disease-causing significant impact on the dairy industry. Therefore, it leads to an increase in dairy farming to meet commercial demands. As a result, there is a major impact on both the dairy industry and the environment including global warming. Recurrent mastitis is often attributed to the development of bacterial biofilms, which promote survival of sessile cells in hostile environments, and resistance to the immune system defense and antimicrobial therapy. Recently, we described the in vitro biofilm development on abiotic surfaces by bovine SDSD. In that work we integrated microbiology, imaging, and computational methods to evaluate the biofilm production capability of SDSD isolates on abiotic surfaces. Additionally, we reported that bovine SDSD can adhere and internalize human cells, including human epidermal keratinocyte (HEK) cells. We showed that the adherence and internalization rates of bovine SDSD isolates in HEK cells are higher than those of a SDSD DB49998-05 isolated from humans. In vivo, bovine SDSD can cause invasive infections leading to zebrafish morbidity and mortality. In the present work, we investigated for the first time the capability of bovine SDSD to develop biofilm in vivo using a murine animal model and ex-vivo on human HEK cells. Bovine SDSD isolates were selected based on their ability to form weak, moderate, or strong biofilms on glass surfaces. Our results showed that SDSD isolates displayed an increased ability to form biofilms on the surface of catheters implanted in mice when compared to in vitro biofilm formation on abiotic surface. A greater ability to form biofilm in vitro after animal passage was observed for the VSD45 isolate, but not for the other isolates tested. Besides that, in vitro scanning electron microscopy demonstrated that SDSD biofilm development was visible after 4 hours of SDSD adhesion to HEK cells. Cell viability tests showed an important reduction in the number of HEK cells after the formation of SDSD biofilms. In this study, the expression of genes encoding BrpA-like (biofilm regulatory protein), FbpA (fibronectin-binding protein A), HtrA (serine protease), and SagA (streptolysin S precursor) was higher for biofilm grown in vivo than in vitro, suggesting a potential role for these virulence determinants in the biofilm-development, host colonization, and SDSD infections. Taken together, these results demonstrate that SDSD can develop biofilms in vivo and on the surface of HEK cells causing important cellular damages. As SDSD infections are considered zoonotic diseases, our data contribute to a better understanding of the role of biofilm accumulation during SDSD colonization and pathogenesis not only in bovine mastitis, but they also shed some lights on the mechanisms of prosthesis-associated infection and cellulitis caused by SDSD in humans, as well.}, } @article {pmid35926730, year = {2022}, author = {Meganathan, Y and Vishwakarma, A and Ramya, M}, title = {Biofilm formation and social interaction of Leptospira in natural and artificial environments.}, journal = {Research in microbiology}, volume = {173}, number = {8}, pages = {103981}, doi = {10.1016/j.resmic.2022.103981}, pmid = {35926730}, issn = {1769-7123}, mesh = {Humans ; *Leptospira ; Social Interaction ; *Leptospirosis/microbiology ; Biofilms ; Virulence ; }, abstract = {In the recent decades, there has been increased interest in the study on social interactions of pathogenic bacteria and biofilm-forming microbes. Leptospira is a zoonotic pathogen that causes human leptospirosis. Biofilm formation by pathogenic and saprophytic Leptospira has been documented in various biotic and abiotic environments. Biofilm supports cell growth and protects them from a variety of environmental stress. Pathogenic bacterial biofilm might increase the virulence and pathogenesis. However, research on the social behaviour and biofilm production by Leptospira is limited. This review discusses the interplay between the different species in the biofilm formation of saprophytic and pathogenic Leptospira and potential future applications.}, } @article {pmid35926621, year = {2022}, author = {Battulga, B and Atarashi-Andoh, M and Nakanishi, T and Koarashi, J}, title = {A new approach to extracting biofilm from environmental plastics using ultrasound-assisted syringe treatment for isotopic analyses.}, journal = {The Science of the total environment}, volume = {849}, number = {}, pages = {157758}, doi = {10.1016/j.scitotenv.2022.157758}, pmid = {35926621}, issn = {1879-1026}, mesh = {Biofilms ; Carbon ; Cesium Radioisotopes ; Microplastics ; Nitrogen ; *Plastics/analysis ; *Syringes ; }, abstract = {Plastics are one of the ubiquitous and artificial types of substrates for microbial colonization and biofilm development in the aquatic environment. Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon (δ[13]C) and nitrogen (δ[15]N) isotope signatures and their interactions with radionuclides especially radiocesium ([137]Cs). The extraction method is simple and cost-effective, requiring only an ultrasonic bath, disposable plastic syringes, and a freeze drier. After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments, with less contamination from plastics and other mineral particles. Effective removal of small microplastics from the experimental suspension was satisfactorily achieved using the method with syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed [137]Cs activity concentrations of <75 to 820 Bq·kg[-1] biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for [137]Cs in the coastal riverine environment. Significant differences in the δ[13]C and δ[15]N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics. We demonstrate here a straightforward method for extracting biofilms from environmental plastics; the results obtained with this method could provide useful insights into the plastic-associated nutrient cycling in the environment.}, } @article {pmid35926593, year = {2022}, author = {Zhao, Y and Zhu, S and Fan, X and Zhang, X and Ren, H and Huang, H}, title = {Precise portrayal of microscopic processes of wastewater biofilm formation: Taking SiO2 as the model carrier.}, journal = {The Science of the total environment}, volume = {849}, number = {}, pages = {157776}, doi = {10.1016/j.scitotenv.2022.157776}, pmid = {35926593}, issn = {1879-1026}, mesh = {Bacterial Adhesion ; Biofilms ; *Silicon Dioxide ; Surface Properties ; *Wastewater ; }, abstract = {Precise characterization of the microscopic processes of wastewater biofilm formation is essential for regulating biofilm behavior. Nevertheless, it remains a great challenge. This study investigated biofilm formation on SiO2 carriers under gradually increasing shear force combining the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory in a Couette-Taylor reactor, and precisely revealed the micro-interface interaction and species colonization during biofilm formation. The results indicated that bacterial reversible adhesion distance on SiO2 carrier surface was 3.06 ± 0.48 nm. Meanwhile, the secondary minimum of total XDLVO interaction energy could be used as a novel indicator to distinguish biofilm formation stages. The revealed biofilm formation stages were also confirmed by the electrochemical analysis. Additionally, the pioneer species that colonized at first were Comamonadaceae, Azospira, Flavobacterium and Azonexus, while keystone species such as Hydrogenophaga, AKYH767, Aquimonas and Ignavibacterium determined the stability of microbial community. In conclusion, this study provided a methodological example to study wastewater biofilm micro-interface behavior through the integration of an experimental platform as well as multiple monitoring and analysis methods, which opened up new perspectives for biofilm research and provided useful guidance for the regulation of biofilm-related treatment processes and new technology development.}, } @article {pmid35924980, year = {2022}, author = {Wang, J and Tabassum, N and Toma, TT and Wang, Y and Gahlmann, A and Acton, ST}, title = {3D GAN image synthesis and dataset quality assessment for bacterial biofilm.}, journal = {Bioinformatics (Oxford, England)}, volume = {38}, number = {19}, pages = {4598-4604}, pmid = {35924980}, issn = {1367-4811}, support = {1R01GM139002//US National Institute of General Medical Sciences/ ; }, mesh = {*Image Processing, Computer-Assisted/methods ; *Imaging, Three-Dimensional ; Biofilms ; }, abstract = {MOTIVATION: Data-driven deep learning techniques usually require a large quantity of labeled training data to achieve reliable solutions in bioimage analysis. However, noisy image conditions and high cell density in bacterial biofilm images make 3D cell annotations difficult to obtain. Alternatively, data augmentation via synthetic data generation is attempted, but current methods fail to produce realistic images.

RESULTS: This article presents a bioimage synthesis and assessment workflow with application to augment bacterial biofilm images. 3D cyclic generative adversarial networks (GAN) with unbalanced cycle consistency loss functions are exploited in order to synthesize 3D biofilm images from binary cell labels. Then, a stochastic synthetic dataset quality assessment (SSQA) measure that compares statistical appearance similarity between random patches from random images in two datasets is proposed. Both SSQA scores and other existing image quality measures indicate that the proposed 3D Cyclic GAN, along with the unbalanced loss function, provides a reliably realistic (as measured by mean opinion score) 3D synthetic biofilm image. In 3D cell segmentation experiments, a GAN-augmented training model also presents more realistic signal-to-background intensity ratio and improved cell counting accuracy.

https://github.com/jwang-c/DeepBiofilm.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.}, } @article {pmid35924771, year = {2022}, author = {Chesnokova, MG and Chesnokov, VA and Mironov, AY and Blesman, AI and Polonyankin, DA}, title = {Analysis of micro-relief of biofilm of yeast Candida albicans of basic plastics by the method of laser modulation interference microscopy.}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {67}, number = {7}, pages = {407-413}, doi = {10.51620/0869-2084-2022-67-7-407-413}, pmid = {35924771}, issn = {0869-2084}, mesh = {Biofilms ; *Candida albicans ; Humans ; Lasers ; Microscopy, Confocal ; Microscopy, Interference ; *Plastics ; }, abstract = {The development of mycotic colonization of the base surface with further biodegradation of acrylic plastics is currently of undoubted interest. The oral cavity is a favorable ecological niche for colonization by fungi and their subsequent possible invasion into the epithelium of the oral mucosa. The method of modulation interference laser microscopy is of considerable interest to researchers in medicine in the context of obtaining the necessary information about the morphological characteristics of microbial cells and the microbiome community as a whole during the colonization of a certain ecological niche in the human body. Purpose of the study: to analyze the microrelief of the biofilm of yeast-like fungi of the species Candida albicans of base plastics of the hot type of polymerization using the method of laser modulation interference microscopy. An experimental study was carried out in order to study biofilms of yeast-like fungi of the genus Candida on samples of basic plastics, an image of a biofilm of yeast-like fungi of the species Candida albicans was obtained on the surface of a plastic of a hot type of polymerization (polymethyl methacrylate) in the visualization of the phase portrait, a description of its horizontal and vertical bioprofile. As a result of the research, the heterogeneous structure of the biofilm was determined, due to the different density and accumulation of cells along the surface, the characteristics of the surface were established in accordance with the roughness criteria. The microrelief parameters on a separately arbitrarily selected section line allow one to determine the characteristics of the biofilm in the required area and make it possible to judge the nature of its formation in a certain biological niche.}, } @article {pmid35924755, year = {2022}, author = {Veloso, M and Lopez, Y and Bernaus, M and Gabasa, Y and Angles, F and Font-Vizcarra, L and Soto, S}, title = {"In vitro" evaluation of bacterial biofilm formation on different cerclage systems.}, journal = {Journal of biomaterials applications}, volume = {37}, number = {5}, pages = {767-772}, doi = {10.1177/08853282221117059}, pmid = {35924755}, issn = {1530-8022}, mesh = {*Staphylococcus aureus ; *Staphylococcus epidermidis ; Bacterial Adhesion ; Stainless Steel ; Pseudomonas aeruginosa ; Biofilms ; Polymers ; }, abstract = {Cerclage wiring may be used for fracture fixation or osteotomy stabilization in revision arthroplasty. There is a lack of evidence regarding the potential risk of bacterial colonization for the different types of cerclages. The objective of our research is to study the adhesion and biofilm formation of S. epidermidis, S. aureus, and P. aeruginosa on two different cerclage cable models, comparing a polymer cable and a stainless steel metal cable. A two-cm cerclage piece of each material was submerged in 2 mL of tryptic soy broth (TSB) inoculated with 10 μL of a 0.5 McFarland bacterial culture, and incubated at 37°C during 2 h for adhesion and 48 h for biofilm formation. The cerclages were washed with 1xPBS and sonicated in a new culture medium. Aliquots of several dilutions of each sonicated culture were spread in TSB agar and incubated at 37°C for 24 h. The number of colonies was counted. The colony-forming units per ml (CFU/mL) and the percentage of reduction were calculated. Experiments were triplicated. For P. aeruginosa, a statistically significant reduction in biofilm formation was found on the polymer cerclage cable, compared to the metal cerclage cable. Reductions of 59% and 88%, after 2 h and 48 h, respectively, were observed. For S. epidermis and S. aureus, there was a trend towards lower bacterial adhesion and biofilm formation for the polymer cerclage cable. In summary, these results demonstrate that the braided polymer cerclage cable may be less prone to bacterial adherence and biofilm formation compared to the braided metal cerclage cable.}, } @article {pmid35924695, year = {2022}, author = {Maciel Monteiro, R and Oliveira, VC and Galo, R and Andrade, D and Razaboni, AM and Watanabe, E}, title = {Protocol with non-toxic chemicals to control biofilm in dental unit waterlines: physical, chemical, mechanical and biological perspective.}, journal = {Biofouling}, volume = {38}, number = {6}, pages = {628-642}, doi = {10.1080/08927014.2022.2106857}, pmid = {35924695}, issn = {1029-2454}, mesh = {*Biofilms ; Colony Count, Microbial ; Corrosion ; Dental Equipment ; *Equipment Contamination ; Water Microbiology ; }, abstract = {Biosafety in dentistry aims to combat cross-contamination and biofilm in dental unit waterlines. The aim was to investigate from a physical, chemical, mechanical and biological perspective, a protocol for using chemical products (citric acid, sodium bicarbonate and sodium chloride) to improve and maintain water quality in dental unit waterlines. Change in microhardness and corrosion tendency were observed in stainless steel samples. On the polyurethane surfaces, there were changes in color, microhardness and roughness. Anti-biofilm evaluations revealed a significant reduction in the biofilm biomass, metabolic activity and residual biofilm. These findings suggest that the protocol analyzed in this study showed an innovative potential against biofilm in dental unit waterlines, preserving the physical, chemical and mechanical properties of the materials.}, } @article {pmid35924687, year = {2022}, author = {Abdeljelil, N and Ben Miloud Yahia, N and Landoulsi, A and Chatti, A and Wattiez, R and Van Houdt, R and Gillan, D}, title = {Growth and biofilm formation of Cupriavidus metallidurans CH34 on different metallic and polymeric materials used in spaceflight applications.}, journal = {Biofouling}, volume = {38}, number = {6}, pages = {643-655}, doi = {10.1080/08927014.2022.2106858}, pmid = {35924687}, issn = {1029-2454}, mesh = {Alloys ; Biofilms ; *Cupriavidus/chemistry ; Polytetrafluoroethylene ; *Space Flight ; Stainless Steel ; Titanium ; }, abstract = {Bacteria biofilm formation and its complications are of special concern in isolated structures, such as offshore stations, manned submarines and space habitats, as maintenance and technical support are poorly accessible due to costs and/or logistical challenges. In addition, considering that future exploration missions are planned to adventure farther and longer in space, unlocking biofilm formation mechanisms and developing new antifouling solutions are key goals in order to ensure spacecraft's efficiency, crew's safety and mission success. In this work, we explored the interactions between Cupriavidus metallidurans, a prevalently identified contaminant onboard the International Space Station, and aerospace grade materials such as the titanium alloy TiAl6V4, the stainless steel AISI 316 (SS316) and Polytetrafluoroethylene (PTFE) or Teflon. Borosilicate glass was used as a control and all surfaces were investigated at two different pH values (5.0 and 7.0). Biofilms were almost absent on stainless steel and the titanium alloy contrary to Teflon and glass that were covered by an extensive biofilm formed via monolayers of scattered matrix-free cells and complex multilayered clusters or communities. Filamentous extracellular DNA structures were observed specifically in the complex multilayered clusters adherent to Teflon, indicating that the employed attachment machinery might depend on the physicochemical characteristics of the surface.}, } @article {pmid35924331, year = {2022}, author = {Japhet, N and Tarchitzky, J and Chen, Y}, title = {Effectiveness of hydrogen peroxide treatments in preventing biofilm clogging in drip irrigation systems applying treated wastewater.}, journal = {Biofouling}, volume = {38}, number = {6}, pages = {575-592}, doi = {10.1080/08927014.2022.2102903}, pmid = {35924331}, issn = {1029-2454}, mesh = {*Agricultural Irrigation ; Biofilms ; Fresh Water ; Hydrogen Peroxide/pharmacology ; *Wastewater ; }, abstract = {The application of treated wastewater (TWW) via pressurized drip irrigation (DI) systems, specifically micro-irrigation, is an effective solution to mitigate water scarcity. TWW contains a higher concentration of nutrients and microbial activity compared to fresh water (FW) and poses a larger danger of fouling and subsequent clogging to DI systems. The goal of this paper was to characterize the effectiveness of chemical treatments, specifically hydrogen peroxide (H2O2) in preventing clogging in DI systems utilizing secondary (ST) and tertiary (TT)_TWW. A novel field model was employed to compare the flow rate (FR), fouling accumulation and composition in laterals and emitters of different treatments. Under ST_TWW irrigation, control treatment performance quickly declined while regular low concentration H2O2 treatments exhibited the lowest amounts of fouling and maintained nominal FR and coefficient of variation (CV). Shock treatments, defined as periodical applications of concentrated chemicals combined with lateral flushing, were ineffective in maintaining satisfactory irrigation performance.}, } @article {pmid35923398, year = {2022}, author = {Kwon, H and Park, SY and Kim, MS and Kim, SG and Park, SC and Kim, JH}, title = {Characterization of a Lytic Bacteriophage vB_SurP-PSU3 Infecting Staphylococcus ureilyticus and Its Efficacy Against Biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {925866}, pmid = {35923398}, issn = {1664-302X}, abstract = {In response to the increasing nosocomial infections caused by antimicrobial-resistant coagulase-negative staphylococci (CoNS), bacteriophages (phages) have emerged as an alternative to antibiotics. Staphylococcus ureilyticus, one of the representative species of the CoNS, is now considered a notable pathogen that causes nosocomial bloodstream infections, and its biofilm-forming ability increases pathogenicity and resistance to antimicrobial agents. In this study, a lytic phage infecting S. ureilyticus was newly isolated from wastewater collected from a sewage treatment plant and its biological and antimicrobial characteristics are described. The isolated phage, named vB_SurP-PSU3, was morphologically similar to Podoviridae and could simultaneously lyse some S. warneri strains used in this study. The sequenced genome of the phage consisted of linear dsDNA with 18,146 bp and genome-based phylogeny revealed that vB_SurP-PSU3 belonged to the genus Andhravirus. Although its overall genomic arrangement and contents were similar to those of other members of the Andhravirus, the predicted endolysin of vB_SurP-PSU3 distinctly differed from the other members of the genus. The bacteriolytic activity of vB_SurP-PSU3 was evaluated using S. ureilyticus ATCC 49330, and the phage could efficiently inhibit the planktonic growth of the bacteria. Moreover, the anti-biofilm analysis showed that vB_SurP-PSU3 could prevent the formation of bacterial biofilm and degrade the mature biofilm in vitro. In an additional cytotoxicity assay of vB_SurP-PSU3, no significant adverse effects were observed on the tested cell. Based on these findings, the newly isolated phage vB_SurP-PSU3 could be classified as a new member of Andhravirus and could be considered an alternative potential biocontrol agent against S. ureilyticus infections and its biofilm.}, } @article {pmid35922483, year = {2022}, author = {Sauer, K and Stoodley, P and Goeres, DM and Hall-Stoodley, L and Burmølle, M and Stewart, PS and Bjarnsholt, T}, title = {The biofilm life cycle: expanding the conceptual model of biofilm formation.}, journal = {Nature reviews. Microbiology}, volume = {20}, number = {10}, pages = {608-620}, pmid = {35922483}, issn = {1740-1534}, support = {R01 AI150761/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Life Cycle Stages ; *Pseudomonas aeruginosa/physiology ; }, abstract = {Bacterial biofilms are often defined as communities of surface-attached bacteria and are typically depicted with a classic mushroom-shaped structure characteristic of Pseudomonas aeruginosa. However, it has become evident that this is not how all biofilms develop, especially in vivo, in clinical and industrial settings, and in the environment, where biofilms often are observed as non-surface-attached aggregates. In this Review, we describe the origin of the current five-step biofilm development model and why it fails to capture many aspects of bacterial biofilm physiology. We aim to present a simplistic developmental model for biofilm formation that is flexible enough to include all the diverse scenarios and microenvironments where biofilms are formed. With this new expanded, inclusive model, we hereby introduce a common platform for developing an understanding of biofilms and anti-biofilm strategies that can be tailored to the microenvironment under investigation.}, } @article {pmid35918726, year = {2022}, author = {Weng, L and Wu, L and Guo, R and Ye, J and Liang, W and Wu, W and Chen, L and Yang, D}, title = {Lactobacillus cell envelope-coated nanoparticles for antibiotic delivery against cariogenic biofilm and dental caries.}, journal = {Journal of nanobiotechnology}, volume = {20}, number = {1}, pages = {356}, pmid = {35918726}, issn = {1477-3155}, support = {W0034//Program for Youth Innovation in Future Medicine, Chongqing Medical University/ ; 81700958//National Natural Science Foundation of China/ ; 31970783//National Natural Science Foundation of China/ ; 2020M683271//China Postdoctoral Science Foundation/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Membrane ; *Dental Caries/drug therapy/prevention & control ; Humans ; Lactobacillus ; *Nanoparticles ; Streptococcus mutans ; }, abstract = {BACKGROUND: Due to their prevalence, dental caries ranks first among all diseases endangering human health. Therefore, the prevention of caries is of great significance, as caries have become a serious public health problem worldwide. Currently, using nanoscale drug delivery systems to prevent caries has received increased attention. However, the preventive efficacy of these systems is substantially limited due to the unique physiological structure of cariogenic biofilms. Thus, novel strategies aimed at combating cariogenic biofilms to improve preventive efficiency against caries are meaningful and very necessary. Herein, inspired by cell membrane coating technology and Lactobacillus strains, we coated triclosan (TCS)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TCS@PLGA-NPs) with an envelope of Lactobacillus (LA/TCS@PLGA-NPs) and investigated their potential as a nanoparticle delivery system against cariogenic biofilms and dental caries.

RESULTS: LA/TCS@PLGA-NPs were successfully prepared with favorable properties, including a coated envelope, controllable size, negative charge, sustained drug-release kinetics and so on. The LA/TCS@PLGA-NPs inherited native properties from the source cell surface, thus the LA/TCS@PLGA-NPs adhered to S. mutans, integrated into the S. mutans biofilm, and interfered with the biofilm formation of S. mutans. The nanoparticles significantly inhibited the activity, biomass and virulence gene expression of S. mutans biofilms in vitro. Additionally, LA/TCS@PLGA-NPs exhibited a long-lasting inhibitory effect on the progression of caries in vivo. The safety performance of the nanoparticles is also favorable.

CONCLUSIONS: Our findings reveal that the antibiofilm effect of LA/TCS@PLGA-NPs relies not only on the inheritance of native properties from the Lactobacillus cell surface but also on the inhibitory effect on the activity, biomass and virulence of S. mutans biofilms. Thus, these nanoparticles could be considered feasible candidates for a new class of effective drug delivery systems for the prevention of caries. Furthermore, this work provides new insights into cell membrane coating technology and presents a novel strategy to combat bacterial biofilms and associated infections.}, } @article {pmid35916587, year = {2022}, author = {Kang, T and Yim, D and Baek, KH and Lee, YE and Kim, HJ and Jo, C}, title = {The inactivation efficacy of plasma-activated acetic acid against Salmonella Typhimurium cells and biofilm.}, journal = {Journal of applied microbiology}, volume = {133}, number = {5}, pages = {3007-3019}, doi = {10.1111/jam.15757}, pmid = {35916587}, issn = {1365-2672}, support = {2021R1I1A1A01044665//Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education/ ; }, mesh = {*Salmonella typhimurium ; Catalase ; *Acetic Acid/pharmacology ; Hydrogen Peroxide/pharmacology ; Histidine ; Hydroxyl Radical ; Nitrites ; Sodium Azide ; Singlet Oxygen ; Nitrates ; Peroxynitrous Acid ; Nitrogen Dioxide ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Mannitol ; Water ; Food Microbiology ; Colony Count, Microbial ; }, abstract = {AIM: This study aimed to examine the inactivation efficacy of plasma-activated acetic acid (PAAA) against Salmonella Typhimurium cells and biofilm and elucidate underlying chemical inactivation pathway.

METHODS AND RESULTS: PAAA was prepared by discharging plasma to 20 ml of 0.2% (v/v) acetic acid (AA) for 20 min (2.2 kHz and 8.4 kVpp). The count of cells and biofilms decreased by 5.71 log CFU ml[-1] and 4 log CFU/cm[2] after 10 min of treatment with 0.2% PAAA and 0.4% PAAA compared with control group (without any treatment), respectively. In 0.2% PAAA, the concentrations of hydrogen peroxide (H2 O2) and nitrate anions were directly proportional to the plasma discharge time, whilst nitrite anion (NO2 [-]) was not detected. However, the pH values of both 0.2% PAAA and plasma-activated water were inversely proportional to the plasma discharge time. Treatment with catalase, L-histidine, D-mannitol and sodium azide inhibited the antibacterial activity of PAAA.

CONCLUSION: H2 O2 , singlet oxygen, hydroxyl radical and NO2 [-] are involved in the generation and decomposition of peroxynitrous acid generated from PAAA functioned as intermediate agent, which could diffuse through cell membranes of bacteria and induce cell injury.

This study provides the understanding of efficacy and selectivity of PAAA which could be a novel decontamination agent.}, } @article {pmid35914572, year = {2022}, author = {Mendes-Gouvêa, CC and Danelon, M and Vieira, APM and do Amaral, JG and de Souza Neto, FN and Gorup, LF and Camargo, ER and Delbem, ACB and Barbosa, DB}, title = {Silver nanoparticles associated with a polyphosphate and fluoride enhance the prevention of enamel demineralization and impact on dual-biofilm adhesion.}, journal = {Journal of dentistry}, volume = {125}, number = {}, pages = {104245}, doi = {10.1016/j.jdent.2022.104245}, pmid = {35914572}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Calcium ; Candida albicans ; Cariostatic Agents/pharmacology ; Cattle ; *Dental Caries/prevention & control ; Dental Enamel ; Fluorides/pharmacology ; *Metal Nanoparticles ; Polyphosphates/pharmacology ; Silver/pharmacology ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVES: The aim of this study were to produce a multifunctional nanocomposite combining silver nanoaparticles (Ag), sodium trimetaphosphate (TMP) and fluoride (F), to investigate its effect on dental enamel demineralization and on biofilms of Streptococcus mutans and Candida albicans.

METHODS: Bovine enamel blocks were submitted to five pH cycles and treated 2x/day with 100 ppm F, 225 ppm F, 100 ppm F + 0.2%TMP or 100 ppm F + 0.2%TMP+10% Ag (100F/TMP/Ag). Next, surface hardness loss (%SH), integrated loss of subsurface hardness (ΔKHN), enamel fluoride (F) and calcium (Ca) concentration were determined. Biofilms from single and dual species of S. mutans and C. albicans were treated with 100F/TMP/Ag, Ag or chlorhexidine gluconate for 24 h. The antibiofilm effect was evaluated by colony-forming unit counting and Scanning Electron Microscopy.

RESULTS: The nanocomposite reduced 43.0% of %SH and was similar with samples treated with 225F, 100F/TMP and 100/TMP/Ag. The attribute of F and/or TMP in reducing ΔKHN in 5-20 μm was not affected by the addiction of Ag (110F = 225F = 100F/TMP = 100F/TMP/Ag > Negative Control). Further, 100F/TMP/Ag strongly reduced viable cells of S. mutans in dual biofilms (∼5 log10cm[2]) and structurally affected the biofilms.

CONCLUSION: The 100F/TMP/F promoted a protective effect against enamel demineralization and was able to significantly inhibit the growth of biofilms of S. mutans and C. albicans.

CLINICAL SIGNIFICANCE: The focus on prevention and non-invasive dental treatment is the most effective and least costly way to improve the population's oral health conditions. We present a nanocomposite for a multiple approach in prevention of caries.}, } @article {pmid35914415, year = {2022}, author = {Das, MC and Samaddar, S and Jawed, JJ and Ghosh, C and Acharjee, S and Sandhu, P and Das, A and Daware, AV and De, UC and Majumdar, S and Das Gupta, SK and Akhter, Y and Bhattacharjee, S}, title = {Vitexin alters Staphylococcus aureus surface hydrophobicity to obstruct biofilm formation.}, journal = {Microbiological research}, volume = {263}, number = {}, pages = {127126}, doi = {10.1016/j.micres.2022.127126}, pmid = {35914415}, issn = {1618-0623}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Apigenin ; Azithromycin/pharmacology ; Biofilms ; Gentamicins/pharmacology ; Hydrophobic and Hydrophilic Interactions ; Mice ; Microbial Sensitivity Tests ; *Staphylococcal Infections/microbiology ; *Staphylococcus aureus ; }, abstract = {Cell Surface hydrophobicity is one of the determinant biophysical parameters of bacterial aggregation for being networked to form a biofilm. Phytoconstituent, like vitexin, has long been in use for their antibacterial effect. The present work demonstrates the role of vitexin in modulating Staphylococcus aureus surface hydrophobicity while aggregating to form biofilm and pathogenesis in a host. In planktonic form, vitexin shows minimum inhibitory concentration at 252 µg/ml against S. aureus. Sub-MIC doses of vitexin and antibiotics (26 µg/ml of vitexin, 55 µg/ml of azithromycin, and 2.5 µg/ml of gentamicin) were selected to treat S. aureus. Dead cell counts after treatment were studied through flow cytometry. As dead cell counts were minimal (<5 %), these doses were considered for all subsequent experiments. While studying aggregating cells, it was observed that vitexin reduces S. aureus surface hydrophobicity and membrane permeability at the sub-MIC dose of 26 µg/ml. The in silico binding analysis showed a higher binding affinity of vitexin with surface proteins (IcaA, DltA, and SasG) of S. aureus. Down-regulation of dltA and icaAB expression, along with the reduction in membrane potential with a sub-MIC dose of vitexin, explains reduced S. aureus surface hydrophobicity. Vitexin was found to interfere with S. aureus biofilm-associated protein biomass, EPS production, and swarming movement. Subsequently, the suppression of proteases production and down-regulation of icaAB and agrAC gene expression with a sub-MIC dose of vitexin explained the inhibition of S. aureus virulence in vitro. Besides, vitexin was also found to potentiate the antibiofilm activity of sub-MIC doses of gentamicin and azithromycin. Treatment with vitexin exhibits a protective response in S. aureus infected macrophages through modulation of expression of cytokines like IL-10 and IL-12p40 at protein and mRNA levels. Furthermore, CFU count and histological examination of infected mouse tissue (liver and spleen) justify the in vivo protective effect of vitexin from S. aureus biofilm-associated infection. From this study, it can be inferred that vitexin can reduce S. aureus surface hydrophobicity, leading to interference with aggregation at the time of biofilm formation and subsequent pathogenesis in a host.}, } @article {pmid35912827, year = {2022}, author = {Muthami, JM and Fernández-García, L and Tomás, M and Wood, TK}, title = {What is the fate of the biofilm matrix?.}, journal = {Environmental microbiology}, volume = {24}, number = {10}, pages = {4495-4499}, doi = {10.1111/1462-2920.16097}, pmid = {35912827}, issn = {1462-2920}, mesh = {Bacterial Proteins ; *Biofilms ; Extracellular Matrix ; *Extracellular Polymeric Substance Matrix ; }, } @article {pmid35912797, year = {2022}, author = {Samuel, MS and Moghaddam, ST and Shang, M and Niu, J}, title = {A Flexible Anti-Biofilm Hygiene Coating for Water Devices.}, journal = {ACS applied bio materials}, volume = {5}, number = {8}, pages = {3991-3998}, doi = {10.1021/acsabm.2c00538}, pmid = {35912797}, issn = {2576-6422}, mesh = {Anti-Bacterial Agents/chemistry ; Bacteria ; *Bacterial Adhesion ; Coated Materials, Biocompatible/chemistry ; Escherichia coli ; Hygiene ; *Stainless Steel/chemistry ; Water ; }, abstract = {Biofilm is a microbiome complex comprising different bacterial colonies that typically adhere to device surfaces in water, which causes serious medical issues such as indwelling infections and outbreaks. Here, we developed a non-nanoparticle, flexible anti-biofilm hygiene coating consisting of lithocholic acid (LCA), zinc pyrithione (Zn), and cinnamaldehyde (Cn) (named as LCA-Zn-Cn) that largely prevents the bacteria adhesion to various water device surfaces such as stainless steel and glass through a synergistic mechanism. The existing chelated groups on LCA and Cn attract plenty of bacteria via hydrophobic interaction. Both the bactericidal reaction by grafting biocidal groups from both LCA and Cn and the bacteriostatic reaction by inhibiting cell division via zinc ions (Zn) lead to a largely improved bacteria/biofilm prevention. The antibacterial performance was assessed by using the JIS Z 2801/ISO 22196 method. The designed LCA-Zn-Cn coating displayed log10 reduction of 4.23 (99.9% reduction) of E. coli and log10 reduction of 3.51 (99.8% reduction) of E. faecalis on stainless steel, which are much higher than the control samples, demonstrating a promising colonization inhibition. In parallel, the polysulfone encapsulated beads also showed >99% reduction efficiency in batch and >97-98% reduction efficiency in continuous column tests using the Lake Michigan water. Due to the strong cross-linked configuration, the coating still showed >90.9% bacterial reduction after 3000 abrasion cycles and over 99.9% bacteria reduction after a high flow velocity of 1.99 m/s test, which confirmed the enhanced mechanical durability. By applying either spray or dip-coating, the designed polymer composite can be coated on a variety of irregular water devices with mass production using an auto-controlled robot arm.}, } @article {pmid35912471, year = {2022}, author = {Cui, F and Ning, Y and Wang, D and Li, J and Li, X and Li, T}, title = {Carbon dot-based therapeutics for combating drug-resistant bacteria and biofilm infections in food preservation.}, journal = {Critical reviews in food science and nutrition}, volume = {}, number = {}, pages = {1-17}, doi = {10.1080/10408398.2022.2105801}, pmid = {35912471}, issn = {1549-7852}, abstract = {Drug-resistant bacteria are caused by antibiotic abuse and/or biofilm formation and have become a threat to the food industry. Carbon dot (CD)-based nanomaterials are a very promising tools for combating pathogenic and spoilage bacteria, and they possess exceptional and adjustable photoelectric and chemical properties. In view of the rapid development of CD-based nanomaterials and their increasing popularity in the food industry, a comprehensive and updated review is needed to summarize their antimicrobial mechanisms and applications in foods. This review discusses the synthesis of CDs, antimicrobial mechanisms, and their applications for extending the shelf life of food. It includes the synthesis of CDs using small molecules, polymers, and biomass. It also discusses the different antimicrobial mechanisms of CDs and their use as antibacterial agents and carriers/ligands. CD-based materials have proven effective against pathogenic and spoilage bacteria in food by inhibiting planktonic bacteria and biofilms. Optimization of the production parameters of CDs can help them achieve a full-spectral response, but degradability still requires further research.}, } @article {pmid35911104, year = {2022}, author = {Farkas, Á and Balázs, VL and Kõszegi, T and Csepregi, R and Kerekes, E and Horváth, G and Szabó, P and Gaál, K and Kocsis, M}, title = {Antibacterial and Biofilm Degradation Effects of Hungarian Honeys Linked With Botanical Origin, Antioxidant Capacity and Mineral Content.}, journal = {Frontiers in nutrition}, volume = {9}, number = {}, pages = {953470}, pmid = {35911104}, issn = {2296-861X}, abstract = {The aim of the study was to assess the impact of four unifloral honeys on the food-borne pathogens Pseudomonas aeruginosa and Staphylococcus aureus, by analyzing the honeys' antibacterial and biofilm degradation effects, as well as their antioxidant activity and element content. Linden and milkweed honeys represented light colored honeys, while goldenrod and chestnut honeys the darker ones. The botanical origin of the honeys and the relative frequency of their pollen types were established with melissopalynological analysis. The antioxidant capacities were calculated by two single electron transfer based methods (TRC - Total Reducing Capacity and TEAC - Trolox Equivalent Antioxidant Capacity) and a hydrogen atom transfer based assay (ORAC - Oxygen Radical Absorbance). The amount of four main macro- and two microelements was quantified. The antibacterial activity was determined by minimum inhibitory concentration (MIC) and membrane degradation assays. Furthermore, the biofilm degradation power of the samples was studied as well. The light colored linden honey with the lowest TRC and TEAC, but with the highest ORAC antioxidant activity and high element content showed the best antibacterial and biofilm degradation effects. Meanwhile, the dark colored chestnut honey with significantly higher single electron transfer based antioxidant capacities, with high element content, but lower ORAC showed significantly higher MIC and lower membrane degradation activity than linden honey. In case of biofilm degradation, both honey types gave similarly high inhibitory effect. Goldenrod honey was similarly effective regarding its MIC properties like chestnut honey, but had significantly lower antioxidant potential and ability to disrupt bacterial membranes and biofilms. Milkweed honey was the honey type with the lowest bioactivity and element content. The honeys, unequivocally characterized by their antioxidant characters and element content, displayed different antibacterial and biofilm degradation effects. In addition, some honey traits were found to be good predictors of the antimicrobial potential of honeys: ORAC assay showed correlation with the MIC values of both bacteria, and strict correlation was found between the mineral content and the antibiofilm activity of the studied honeys. Our studies indicate that unifloral honeys, such as linden and chestnut honeys, are plant-derived products with great potential as antimicrobial agents in food preservation, exhibiting remarkable antibacterial activity against food-borne pathogens.}, } @article {pmid35909974, year = {2022}, author = {Al-Zawity, J and Afzal, F and Awan, A and Nordhoff, D and Kleimann, A and Wesner, D and Montier, T and Le Gall, T and Müller, M}, title = {Effects of the Sex Steroid Hormone Estradiol on Biofilm Growth of Cystic Fibrosis Pseudomonas aeruginosa Isolates.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {941014}, pmid = {35909974}, issn = {2235-2988}, mesh = {Biofilms ; *Cystic Fibrosis/microbiology ; Estradiol/pharmacology ; Extracellular Polymeric Substance Matrix ; Female ; Humans ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa ; }, abstract = {Women with cystic fibrosis (CF) have a significantly lower life expectancy compared to men, which is indicated by an earlier impairment of lung function due to chronic colonization with biofilm formed by Pseudomonas aeruginosa. There is growing evidence that blood serum concentrations of the steroid sex hormone estradiol (E2) correlate with the occurrence of pulmonary exacerbations in CF but also play a role in the mucoid switch of P. aeruginosa. This study aims to shed light on possible microbiological reasons for sexual dimorphism in CF by investigating the influence of E2 on biofilm formation of P. aeruginosa CF isolates. For this purpose, 10 CF isolates of the respiratory tract derived from different CF patients have been treated with E2 in a microtiter plate biofilm model. Biofilms have been examined by crystal violet assays, field emission scanning electron microscopy (FE-SEM), 3D laser scanning microscopy (LSM), and quorum sensing (QS) reporter assays of the supernatants taken from biofilms. This allowed us to simultaneously investigate the effects of E2 on attached biofilm mass, biofilm ultrastructure, and QS activity. Upon E2 treatment, six out of 10 investigated CF isolates showed an increase of attached biofilm mass, whereas biofilms from two tested non-CF laboratory strains (PAO1 and ATCC19660) did not. Moreover, FE-SEM and 3D LSM analyses of the E2 responsive CF biofilms revealed ultrastructural remodeling of biofilm structure at different scales with increased formation of prominent biofilm spots, enhanced coverage with extracellular polymeric substance (EPS), and extended average surface roughness. QS activity measurements performed in biofilm supernatants via luminescence acyl homoserine lactone (AHL) reporter assays further showed that E2 treatment may also modulate QS signaling, as shown in an E2 sensitive CF isolate. Together, our results suggest the biofilm modulating effects of E2 on various clinical CF isolates that are documented by both biomass and ultrastructural changes of biofilms. The gained new insight into the influence of steroid hormones on P. aeruginosa biofilm phenotypes might pave the way for novel future approaches in personalized medicine based on the patients' sex and hormonal status.}, } @article {pmid35909964, year = {2022}, author = {Baishya, J and Everett, JA and Chazin, WJ and Rumbaugh, KP and Wakeman, CA}, title = {The Innate Immune Protein Calprotectin Interacts With and Encases Biofilm Communities of Pseudomonas aeruginosa and Staphylococcus aureus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {898796}, pmid = {35909964}, issn = {2235-2988}, support = {R15 GM128072/GM/NIGMS NIH HHS/United States ; R01 AI127793/AI/NIAID NIH HHS/United States ; R01 CA118089/CA/NCI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/immunology/pharmacology ; *Biofilms ; Extracellular Polymeric Substance Matrix/genetics/immunology ; Humans ; *Immunity, Innate/genetics/immunology ; *Leukocyte L1 Antigen Complex/genetics/immunology ; Phagocytosis ; *Pseudomonas aeruginosa/genetics/immunology ; *Staphylococcus aureus/genetics/immunology ; }, abstract = {Calprotectin is a transition metal chelating protein of the innate immune response known to exert nutritional immunity upon microbial infection. It is abundantly released during inflammation and is therefore found at sites occupied by pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. The metal limitation induced by this protein has previously been shown to mediate P. aeruginosa and S. aureus co-culture. In addition to the transition metal sequestration role of calprotectin, it has also been shown to have metal-independent antimicrobial activity via direct cell contact. Therefore, we sought to assess the impact of this protein on the biofilm architecture of P. aeruginosa and S. aureus in monomicrobial and polymicrobial culture. The experiments described in this report reveal novel aspects of calprotectin's interaction with biofilm communities of P. aeruginosa and S. aureus discovered using scanning electron microscopy and confocal laser scanning microscopy. Our results indicate that calprotectin can interact with microbial cells by stimulating encapsulation in mesh-like structures. This physical interaction leads to compositional changes in the biofilm extracellular polymeric substance (EPS) in both P. aeruginosa and S. aureus.}, } @article {pmid35909621, year = {2022}, author = {Upmanyu, K and Haq, QMR and Singh, R}, title = {Factors mediating Acinetobacter baumannii biofilm formation: Opportunities for developing therapeutics.}, journal = {Current research in microbial sciences}, volume = {3}, number = {}, pages = {100131}, pmid = {35909621}, issn = {2666-5174}, abstract = {Acinetobacter baumannii has notably become a superbug due to its mounting risk of infection and escalating rates of antimicrobial resistance, including colistin, the last-resort antibiotic. Its propensity to form biofilm on biotic and abiotic surfaces has contributed to the majority of nosocomial infections. Bacterial cells in biofilms are resistant to antibiotics and host immune response, and pose challenges in treatment. Therefore current scenario urgently requires the development of novel therapeutic strategies for successful treatment outcomes. This article provides a holistic understanding of sequential events and regulatory mechanisms directing A. baumannii biofilm formation. Understanding the key factors functioning and regulating the biofilm machinery of A. baumannii will provide us insight to develop novel approaches to combat A. baumannii infections. Further, the review article deliberates promising strategies for the prevention of biofilm formation on medically relevant substances and potential therapeutic strategies for the eradication of preformed biofilms which can help tackle biofilm-associated A. baumannii infections. Advances in emerging therapeutic opportunities such as phage therapy, nanoparticle therapy and photodynamic therapy are also discussed to comprehend the current scenario and future outlook for the development of successful treatment against biofilm-associated A. baumannii infections.}, } @article {pmid35909185, year = {2022}, author = {Matilla-Cuenca, L and Taglialegna, A and Gil, C and Toledo-Arana, A and Lasa, I and Valle, J}, title = {Bacterial biofilm functionalization through Bap amyloid engineering.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {62}, pmid = {35909185}, issn = {2055-5008}, mesh = {Amyloid/metabolism ; Amyloidogenic Proteins/genetics/metabolism ; *Bacterial Proteins/genetics/metabolism ; Biofilms ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus/physiology ; }, abstract = {Biofilm engineering has emerged as a controllable way to fabricate living structures with programmable functionalities. The amyloidogenic proteins comprising the biofilms can be engineered to create self-assembling extracellular functionalized surfaces. In this regard, facultative amyloids, which play a dual role in biofilm formation by acting as adhesins in their native conformation and as matrix scaffolds when they polymerize into amyloid-like fibrillar structures, are interesting candidates. Here, we report the use of the facultative amyloid-like Bap protein of Staphylococcus aureus as a tool to decorate the extracellular biofilm matrix or the bacterial cell surface with a battery of functional domains or proteins. We demonstrate that the localization of the functional tags can be change by simply modulating the pH of the medium. Using Bap features, we build a tool for trapping and covalent immobilizing molecules at bacterial cell surface or at the biofilm matrix based on the SpyTag/SpyCatcher system. Finally, we show that the cell wall of several Gram-positive bacteria could be functionalized through the external addition of the recombinant engineered Bap-amyloid domain. Overall, this work shows a simple and modulable system for biofilm functionalization based on the facultative protein Bap.}, } @article {pmid35908635, year = {2022}, author = {Weng, X and Mao, Z and Fu, HM and Chen, YP and Guo, JS and Fang, F and Xu, XW and Yan, P}, title = {Biofilm formation during wastewater treatment: Motility and physiological response of aerobic denitrifying bacteria under ammonia stress based on surface plasmon resonance imaging.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127712}, doi = {10.1016/j.biortech.2022.127712}, pmid = {35908635}, issn = {1873-2976}, mesh = {*Ammonia/metabolism ; Bacteria/metabolism ; Bacteria, Aerobic/metabolism ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Nitrogen/metabolism ; Surface Plasmon Resonance ; *Wastewater/microbiology ; }, abstract = {A bacterial image analysis system based on surface plasmon resonance imaging was established to investigate the effect of bacterial motility on biofilm formation under high ammonia nitrogen at the single-cell level. The results showed that the bacterial mean rotation speed and vertical motility distance decreased with the increasing concentration of ammonia nitrogen. Ammonia nitrogen inhibited the metabolic activity of the bacteria, decreasing bacterial motility. Bacterial motility was negatively correlated with the biofilm-formation ability. The biofilm formation ability of Enterobacter cloacae strain HNR exposed to ammonia nitrogen was enhanced by reducing its movement and promoting EPS secretion. Genes related to the tricarboxylic acid cycle and oxidative phosphorylation were down-regulated, indicating inhibition of microbial energy metabolism. Genes related to bacterial secretion and lipopolysaccharide synthesis were up-regulated, facilitating the formation of biofilms and enabling the bacteria to resist ammonia nitrogen stress. This study provides new insights into the biofilm formation under ammonia stress.}, } @article {pmid35908341, year = {2022}, author = {Shukla, SK and Rao, TS}, title = {Targeting hydrophobicity in biofilm-associated protein (Bap) as a novel antibiofilm strategy against Staphylococcus aureus biofilm.}, journal = {Biophysical chemistry}, volume = {289}, number = {}, pages = {106860}, doi = {10.1016/j.bpc.2022.106860}, pmid = {35908341}, issn = {1873-4200}, mesh = {Bacterial Proteins/chemistry ; Biofilms ; Humans ; Hydrophobic and Hydrophilic Interactions ; *Staphylococcal Infections ; *Staphylococcus aureus/metabolism ; }, abstract = {In this study, a comprehensive in silico characterization was performed on Bap-family proteins to develop novel approaches to deal with Staphylococcus biofilms with a better understanding of the functional, structural, and topological features of Bap proteins. This study showed that Bap-like proteins in staphylococci are highly acidic, large, and cell-wall anchored proteins with tandem repeats. Structurally, Bap-family proteins have two distinct parts. N terminal part, which contains at least 2-3 calcium-binding EF-hand motifs that play a regulatory role in Bap functioning. Whereas the C-terminal part which predominantly consists of tandem repeats (TR), plays a functional as well as structural role. Bioinformatic analysis of Bap proteins and other homologous proteins revealed the presence of an amyloidogenic heptapeptide (STVTVTF) in the hydrophobic core of TRs of protein, responsible for the protein-protein interactions. The synthetic heptapeptide was tested if the masking effect on surface proteins could inhibit the S. aureus biofilm development and act as an 'antibiofilm-peptide'. The results clearly showed that the heptapeptide was able to inhibit early adhesion as well as biofilm development in the S. aureus biofilms. This approach has a promising potential to treat persistent biofilm-based S. aureus infections where Bap-like proteins do play a significant role.}, } @article {pmid35907751, year = {2022}, author = {Fan, M and Li, M and Yang, Y and Weir, MD and Liu, Y and Zhou, X and Liang, K and Li, J and Xu, HHK}, title = {Dual-functional adhesive containing amorphous calcium phosphate nanoparticles and dimethylaminohexadecyl methacrylate promoted enamel remineralization in a biofilm-challenged environment.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {38}, number = {9}, pages = {1518-1531}, doi = {10.1016/j.dental.2022.07.003}, pmid = {35907751}, issn = {1879-0097}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Calcium Phosphates/pharmacology ; *Dental Caries/drug therapy/prevention & control ; Dental Cements/pharmacology ; Dental Enamel ; Humans ; Lactic Acid ; Methacrylates/pharmacology ; Methylamines ; *Nanoparticles ; Streptococcus mutans ; Tooth Remineralization ; }, abstract = {OBJECTIVE: The cariogenic biofilm on enamel, restoration, and bonding interface is closely related to dental caries and composite restoration failure. Enamel remineralization at adhesive interface is conducive to protecting bonding interface and inhibiting secondary caries. This study intended to assess the remineralization efficiency of adhesive with dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP) on initial caries lesion of biofilm-coated enamel.

METHODS: Artificial initial carious lesion was created via 72-hour immersion in demineralization solution and cariogenic biofilm was formed after 24-hour culture of Streptococcus mutans (S. mutans). Specimens were then divided into 4 groups: enamel control, enamel treated with NACP, DMAHDM and NACP+DMAHDM respectively. Samples next underwent 7-day cycling, 4 h in BHIS (brain heart infusion broth containing 1 % sucrose) and 20 h in AS (artificial saliva) per day. The pH of BHIS was tested daily. So did the concentration of calcium and phosphate in BHIS and AS. Live/dead staining, colony-forming unit (CFU) count, and lactic acid production of biofilms were measured 7 days later. The enamel remineralization efficiency was evaluated by microhardness testing and transverse microradiography (TMR) quantitatively.

RESULTS: Enamel of NACP+DMAHDM group demonstrated excellent remineralization effectiveness. And the NACP+DMAHDM adhesive released a great number of Ca[2+] and PO4[3-] ions, increased pH to 5.81 via acid neutralization, decreased production of lactic acid, and reduced CFU count of S. mutans (P < 0.05).

SIGNIFICANCE: The NACP+DMAHDM adhesive would be applicable to preventing secondary caries, strengthening enamel-adhesive interface, and extending the lifespan of composite restoration.}, } @article {pmid35907535, year = {2022}, author = {Tao, H and Yang, L and Qi, Y and Chen, Y and Yu, D and Zhou, L and Lin, T and Xu, H and Song, J}, title = {Deposition of polystyrene microplastics on bare or biofilm-coated silica analysed via QCM-D.}, journal = {The Science of the total environment}, volume = {847}, number = {}, pages = {157661}, doi = {10.1016/j.scitotenv.2022.157661}, pmid = {35907535}, issn = {1879-1026}, mesh = {Biofilms ; Microplastics ; Plastics ; *Polystyrenes/chemistry ; Quartz Crystal Microbalance Techniques ; *Silicon Dioxide/chemistry ; Surface Properties ; }, abstract = {The mobility of microplastics (MPs) in aqueous media is closely related to their environmental risk. The naturally occurring silica substrate surface in the aquatic environment is easily colonized by microorganisms and forms a biofilm, which may affect the migration and distribution of MPs. Herein, a typical MP, polystyrene (PS), and Pseudomonas fluorescens (P. fluorescens) biofilms were selected to study the deposition and release of pristine or ultraviolet (UV)-aged PS MPs on silica and biofilms under different ionic strengths using a quartz crystal microbalance dissipation (QCM-D) system. Statistical analyses of the deposition experiments revealed a significant impact of P. fluorescens biofilms on deposition (p = 0.0042). The deposition rate of weathered MPs on the biofilms was 4.0 ± 0.1 to 16.3 ± 0.6 times that on silica. A release experiment revealed that the biofilm reduced the release fraction (fr) of weathered MPs by 34.5 ± 0.3 % compared to bare silica. In addition, the UV-ageing treatment reduced the deposition mass of MPs on the surface of silica by 27.6 ± 0.21 % compared to pristine microspheres. The analysis of the deposition mechanism revealed that the promotion and inhibition of biofilm or UV-ageing treatment on the deposition of microspheres could be attributed to the non-Derjaguin-Landau-Verwey-Overbeek (DLVO) force and the decreased electrostatic repulsion or the increased hydration repulsion, respectively.}, } @article {pmid35906280, year = {2022}, author = {El-Atrees, DM and El-Kased, RF and Abbas, AM and Yassien, MA}, title = {Characterization and anti-biofilm activity of bacteriophages against urinary tract Enterococcus faecalis isolates.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {13048}, pmid = {35906280}, issn = {2045-2322}, mesh = {*Bacteriophages ; Biofilms ; Enterococcus ; Enterococcus faecalis ; *Urinary Tract ; }, abstract = {Strong biofilm-forming Enterococcus feacalis urinary tract pathogens (n = 35) were used to determine the lytic spectrum of six bacteriophages isolated from sewage samples. Only 17 Enterococcus feacalis isolates gave lytic zones with the tested bacteriophages from which five isolates were susceptible to all of them. The isolated enterococcal phages are characterized by wide range of thermal (30-90 °C) and pH (3-10) stability. They belong to order Caudovirales, from which four bacteriophages (EPA, EPB, EPD, EPF) belong to family Myoviridae and two (EPC, EPE) belong to family Siphoviridae. In addition, they have promising antibiofilm activity against the tested strong-forming biofilm E. faecalis isolates. The enterococcal phages reduced the formed and preformed biofilms to a range of 38.02-45.7% and 71.0-80.0%, respectively, as compared to the control. The same promising activities were obtained on studying the anti-adherent effect of the tested bacteriophages on the adherence of bacterial cells to the surface of urinary catheter segments. They reduced the number of adherent cells to a range of 30.8-43.8% and eradicated the pre-adherent cells to a range of 48.2-71.1%, as compared to the control. Overall, the obtained promising antibiofilm activity makes these phages good candidates for application in preventing and treating biofilm associated Enterococcus faecalis infections.}, } @article {pmid35905879, year = {2022}, author = {Shi, K and Cheng, W and Jiang, Q and Xue, J and Qiao, Y and Cheng, D}, title = {Insight of the bio-cathode biofilm construction in microbial electrolysis cell dealing with sulfate-containing wastewater.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127695}, doi = {10.1016/j.biortech.2022.127695}, pmid = {35905879}, issn = {1873-2976}, mesh = {Biofilms ; *Desulfovibrio ; Electrodes ; Electrolysis ; Sulfates ; Sulfur Oxides ; *Wastewater ; }, abstract = {Signaling molecules are useful in biofilm formation, but the mechanism for biofilm construction still needs to be explored. In this study, a signaling molecule, N-butyryl-l-Homoserine lactone (C4-HSL), was supplied to enhance the construction of the sulfate-reducing bacteria (SRB) bio-cathode biofilm in microbial electrolysis cell (MEC). The sulfate reduction efficiency was more than 90% in less time under the system with C4-HSL addition. The analysis of SRB bio-cathode biofilms indicated that the activity, distribution, microbial population, and secretion of extracellular polymers prompted by C4-HSL, which accelerate the sulfate reduction, in particular for the assimilatory sulfate reduction pathway. Specifically, the relative abundance of acidogenic fermentation bacteria increased, and Desulfovibrio was co-metabolized with acidogenic fermentation bacteria. This knowledge will help to reveal the potential of signaling molecules to enhance the SRB bio-cathode biofilm MEC construction and improve the performance of treating sulfate-containing wastewater.}, } @article {pmid35905872, year = {2022}, author = {Di Capua, F and Iannacone, F and Sabba, F and Esposito, G}, title = {Simultaneous nitrification-denitrification in biofilm systems for wastewater treatment: Key factors, potential routes, and engineered applications.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127702}, doi = {10.1016/j.biortech.2022.127702}, pmid = {35905872}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors/microbiology ; Denitrification ; *Nitrification ; Nitrogen/metabolism ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Simultaneous nitrification-denitrification (SND) is an advantageous bioprocess that allows the complete removal of ammonia nitrogen through sequential redox reactions leading to nitrogen gas production. SND can govern nitrogen removal in single-stage biofilm systems, such as the moving bed biofilm reactor and aerobic granular sludge system, as oxygen gradients allow the development of multilayered biofilms including nitrifying and denitrifying bacteria. Environmental and operational conditions can strongly influence SND performance, biofilm development and biochemical pathways. Recent advances have outlined the possibility to reduce the carbon and energy consumption of the process via the "shortcut pathway", and simultaneously remove both N and phosphorus under specific operational conditions, opening new possibilities for wastewater treatment. This work critically reviews the factors influencing SND and its application in biofilm systems from laboratory to full scale. Operational strategies to enhance SND efficiency and hints to reduce nitrous oxide emission and operational costs are provided.}, } @article {pmid35905765, year = {2022}, author = {Kaushik, V and Tiwari, M and Tiwari, V}, title = {Interaction of RecA mediated SOS response with bacterial persistence, biofilm formation, and host response.}, journal = {International journal of biological macromolecules}, volume = {217}, number = {}, pages = {931-943}, doi = {10.1016/j.ijbiomac.2022.07.176}, pmid = {35905765}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/metabolism ; *Bacterial Infections ; Bacterial Proteins/metabolism ; Biofilms ; Humans ; Rec A Recombinases/genetics/metabolism ; *SOS Response, Genetics ; }, abstract = {Antibiotics have a primary mode of actions, and most of them have a common secondary mode of action via reactive species (ROS and RNS) mediated DNA damage. Bacteria have been able to tolerate this DNA damage by SOS (Save-Our-Soul) response. RecA is the universal essential key protein of the DNA damage mediated SOS repair in various bacteria including ESKAPE pathogens. In addition, antibiotics also triggers activation of various other bacterial mechanisms such as biofilm formation, host dependent responses, persister subpopulation formation. These supporting the survival of bacteria in unfriendly natural conditions i.e. antibiotic presence. This review highlights the detailed mechanism of RecA mediated SOS response as well as role of RecA-LexA interaction in SOS response. The review also focuses on inter-connection between DNA damage repair pathway (like SOS response) with other survival mechanisms of bacteria such as host mediated RecA induction, persister-SOS interplay, and biofilm-SOS interplay. This understanding of inter-connection of SOS response with different other survival mechanisms will prove beneficial in targeting the SOS response for prevention and development of therapeutics against recalcitrant bacterial infections. The review also covers the significance of RecA as a promising potent therapeutic target for hindering bacterial SOS response in prevailing successful treatments of bacterial infections and enhancing the conventional antibiotic efficiency.}, } @article {pmid35904820, year = {2022}, author = {Del Rey, YC and Parize, H and Pedrazzi, V and Dos Reis, AC and do Nascimento, C}, title = {Clinical and In Situ Oral Biofilm Formation on Dental Implant Abutment Materials: A Systematic Review.}, journal = {The International journal of oral & maxillofacial implants}, volume = {37}, number = {4}, pages = {639-652}, doi = {10.11607/jomi.9352}, pmid = {35904820}, issn = {1942-4434}, mesh = {Alloys ; Biofilms ; *Dental Abutments ; *Dental Implants ; Dental Materials ; Titanium ; Zirconium ; }, abstract = {PURPOSE: This review aimed to summarize the current literature on the oral biofilm formation on alternative abutment materials compared with titanium (Ti) or Ti alloy in clinical and in situ conditions.

MATERIALS AND METHODS: An electronic database search was conducted in PubMed, Cochrane Library, EMBASE, Scopus, Web of Science, LIVIVO, BVS, ProQuest, and OpenGrey up to November 2020. Clinical and in situ studies evaluating the biofilm formed on metallic, ceramic, or polymeric abutment materials compared with Ti or Ti alloy were included. Outcome measures were microbial counts/profile, cell viability, and biofilm coverage/thickness. Clinical parameters were deemed secondary outcomes. Risk of bias was assessed by RoB 2 and ROBINS-I tools.

RESULTS: A total of 10 clinical and 9 in situ studies were included. Meta-analysis was not performed due to heterogeneity across studies. The abutment materials polytetrafluoroethylene, gold alloy, gold-platinum alloy, cobalt-chromium, alumina, and zirconia were reported. Six out of ten clinical studies (60%) and four out of nine in situ studies (44%) found no qualitative or quantitative microbiologic differences between tested materials. When significant differences were detected, conflicting results were reported. Clinical outcomes were consistent with healthy conditions for all investigated materials.

CONCLUSION: There is not enough evidence to support the existence of relevant microbiologic differences in the biofilm formed on alternative abutment materials over Ti and its alloys in oral conditions. No evident relationship between microbiologic results and clinical outcomes were found. In situ studies and polymicrobial analyses showed a higher tendency to find significant differences between materials.}, } @article {pmid35903134, year = {2022}, author = {Elken, EM and Tan, ZN and Wang, Q and Jiang, XY and Wang, Y and Wang, YM and Ma, HX}, title = {Impact of Sub-MIC Eugenol on Klebsiella pneumoniae Biofilm Formation via Upregulation of rcsB.}, journal = {Frontiers in veterinary science}, volume = {9}, number = {}, pages = {945491}, pmid = {35903134}, issn = {2297-1769}, abstract = {The Rcs phosphorelay system is present in many members of the Enterobacteriaceae. The aim of this study was to illustrate the possible mechanisms of eugenol on ultimate targets of Klebsiella pneumoniae (K. pneumoniae) Rcs phosphorelay, rcsB, and impact on biofilm formation. The minimum inhibitory concentration (MIC) of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was determined using the 2-fold micro-dilution method. Biofilm was measured by crystal violet staining. Transcriptome sequencing was performed to investigate sub-MIC eugenol on K. pneumoniae, and gene expression at mRNA level was analyzed by RT-qPCR. In vitro biofilm formation test and molecular docking were used to evaluate the effect of eugenol and to predict potential interactions with RcsB. MicroScale Thermophoresis (MST) was conducted for further validation. MIC of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was both 200 μg/ml. Transcriptome sequencing and RT-qPCR results indicated that rpmg, degP, rnpA, and dapD were downregulated, while rcsB, rcsD, rcsA, yiaG, and yiaD were upregulated in the eugenol-treated group. ΔrcsB exhibited a weakened biofilm formation capacity. Additional isopropyl-β-d-thiogalactoside (IPTG) hinders biofilm formation, while sub-MIC eugenol could promote biofilm formation greatly. Docking analysis revealed that eugenol forms more hydrophobic bonds than hydrogen bonds. MST assay also showed a weak binding affinity between eugenol and RcsB. These results provide significant evidence that rcsB plays a key role in K. pneumoniae biofilm formation. Sub-MIC eugenol facilitates biofilm formation to a large extent instead of inhibiting it. Our findings reveal the potential risk of natural anti-biofilm ingredients at sub-MIC to treat drug-resistance bacteria.}, } @article {pmid35902639, year = {2022}, author = {Shein, AMS and Wannigama, DL and Higgins, PG and Hurst, C and Abe, S and Hongsing, P and Chantaravisoot, N and Saethang, T and Luk-In, S and Liao, T and Nilgate, S and Rirerm, U and Kueakulpattana, N and Srisakul, S and Aryukarn, A and Laowansiri, M and Hao, LY and Yonpiam, M and Ragupathi, NKD and Techawiwattanaboon, T and Ngamwongsatit, N and Amarasiri, M and Ounjai, P and Kupwiwat, R and Phattharapornjaroen, P and Badavath, VN and Leelahavanichkul, A and Kicic, A and Chatsuwan, T}, title = {High prevalence of mgrB-mediated colistin resistance among carbapenem-resistant Klebsiella pneumoniae is associated with biofilm formation, and can be overcome by colistin-EDTA combination therapy.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {12939}, pmid = {35902639}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacteremia/drug therapy ; Bacterial Proteins/metabolism ; *Carbapenem-Resistant Enterobacteriaceae/genetics ; Carbapenems/pharmacology/therapeutic use ; Colistin/pharmacology/therapeutic use ; Drug Resistance, Bacterial/genetics ; Edetic Acid/pharmacology ; *Klebsiella Infections/drug therapy/epidemiology/microbiology ; Klebsiella pneumoniae ; Mice ; Microbial Sensitivity Tests ; Prevalence ; }, abstract = {The global prevalence of colistin-resistant Klebsiella pneumoniae (ColRkp) facilitated by chromosomal and plasmid-mediated Ara4N or PEtN-remodeled LPS alterations has steadily increased with increased colistin usage for treating carbapenem-resistant K. pneumoniae (CRkp). Our study demonstrated the rising trend of ColRkp showing extensively and pandrug-resistant characteristics among CRkp, with a prevalence of 28.5%, which was mediated by chromosomal mgrB, pmrB, or phoQ mutations (91.5%), and plasmid-mediated mcr-1.1, mcr-8.1, mcr-8.2 alone or in conjunction with R256G PmrB (8.5%). Several genetic alterations in mgrB (85.1%) with increased expressions of Ara4N-related phoPQ and pmrK were critical for establishing colistin resistance in our isolates. In this study, we discovered the significant associations between extensively drug-resistant bacteria (XDR) and pandrug-resistant bacteria (PDR) ColRkp in terms of moderate, weak or no biofilm-producing abilities, and altered expressions of virulence factors. These ColRkp would therefore be very challenging to treat, emphasizing for innovative therapy to combat these infections. Regardless of the underlying colistin-resistant mechanisms, colistin-EDTA combination therapy in this study produced potent synergistic effects in both in vitro and in vivo murine bacteremia, with no ColRkp regrowth and improved animal survival, implying the significance of colistin-EDTA combination therapy as systemic therapy for unlocking colistin resistance in ColRkp-associated bacteremia.}, } @article {pmid35901637, year = {2022}, author = {Fu, D and Shao, Y and Li, J and Wu, J and Wu, X and Song, X and Tu, J and Qi, K}, title = {LuxR family transcriptional repressor YjjQ modulates the biofilm formation and motility of avian pathogenic Escherichia coli.}, journal = {Research in veterinary science}, volume = {152}, number = {}, pages = {10-19}, doi = {10.1016/j.rvsc.2022.07.011}, pmid = {35901637}, issn = {1532-2661}, mesh = {Animals ; Biofilms ; Chickens/metabolism ; Escherichia coli/physiology ; *Escherichia coli Infections/veterinary/microbiology ; *Escherichia coli Proteins/genetics/metabolism ; Membrane Transport Proteins/metabolism ; *Poultry Diseases/microbiology ; Trans-Activators/metabolism ; Transcription Factors/genetics/metabolism ; Virulence Factors/genetics ; }, abstract = {Avian pathogenic Escherichia coli (APEC) can cause the acute and sudden death of poultry, which leads to serious economic losses in the poultry industry. Biofilm formation contributes to the persistence of bacterial infection, drug resistance, and resistance to diverse environmental stress. Many transcription regulators in APEC play an essential role in the formation of biofilm and could provide further insights into APEC pathogenesis. YjjQ has an important role in the pathogenicity of bacteria by regulating the expression of virulence factors, such as flagellar and iron uptake. However, YjjQ regulates other virulence factors, and their role in the overall regulatory network is unclear. Here, we further evaluate the function of YjjQ on APEC biofilm formation and motility. In this study, we successfully constructed mutant (AE27∆yjjQ) and complement (AE27ΔyjjQ-comp) strains of the wild-type strain AE27. Inactivation of the yjjQ gene significantly increased biofilm-forming ability in APEC. Scanning electron microscopy showed that the biofilm formation of the AE27 was single-layered and flat, whereas that of the AE27∆yjjQ had a porous three-dimensional structure. Moreover, the deletion of the yjjQ gene inhibited the motility of APEC. RNA-sequencing was used to further investigate the regulatory mechanism of YjjQ in APEC. The results indicate that YjjQ regulates biofilm formation and flagellar genes in AE27∆yjjQ. RT-qPCR shows that YjjQ affects the transcriptional levels of genes, including flagella genes (flhD, flhC and flgE), and biofilm formation genes (pstA, uhpC, nikD, and ygcS). These results confirm that the transcription regulator YjjQ is involved in APEC biofilm formation and motility, and provide new evidence for the prevention and control of APEC.}, } @article {pmid35899682, year = {2022}, author = {Rismayuddin, NAR and Mohd Badri, PEA and Ismail, AF and Othman, N and Bandara, HMHN and Arzmi, MH}, title = {Synbiotic Musa acuminata skin extract and Streptococcus salivarius K12 inhibit candida species biofilm formation.}, journal = {Biofouling}, volume = {38}, number = {6}, pages = {614-627}, doi = {10.1080/08927014.2022.2105142}, pmid = {35899682}, issn = {1029-2454}, mesh = {Biofilms ; Candida ; Candida albicans ; *Musa ; Plant Extracts/pharmacology ; *Streptococcus salivarius ; *Synbiotics ; }, abstract = {This study aimed to determine the effect of synbiotic Musa acuminata skin extract (MASE) and Streptococcus salivarius K12 (K12) on Candida species biofilm formation. Liquid chromatography quadrupole time-of-flight (LC-Q-TOF-MS) was conducted to characterize MASE. To determine the effect of synbiotic on Candida biofilm, 200 µL of RPMI-1640 containing Candida, K12, and MASE were pipetted into the same well and incubated at 37 °C for 72 h. A similar protocol was repeated with K12 or MASE to determine the probiotic and prebiotic effects, respectively. Dimorphism, biofilm biomass, and Candida total cell count (TCC) were determined. A total of 60 compounds were detected in MASE. C. albicans (ALT5) and Candida lusitaniae exhibited the highest reduction in biofilm biomass when co-cultured with prebiotic (77.70 ± 7.67%) and synbiotic (97.73 ± 0.28%), respectively. All Candida spp. had decreased TCC and hyphae when co-cultured with synbiotic. In conclusion, MASE and K12 inhibit Candida biofilm formation.}, } @article {pmid35899046, year = {2022}, author = {Wang, Q and Wang, P and Liu, P and Ou, J}, title = {Comparative Transcriptome Analysis Reveals Regulatory Factors Involved in Vibrio Parahaemolyticus Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {917131}, pmid = {35899046}, issn = {2235-2988}, mesh = {Adenosine Triphosphate/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Extracellular Polymeric Substance Matrix/genetics/metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Humans ; Transcriptome ; *Vibrio parahaemolyticus/genetics ; }, abstract = {Vibrio parahaemolyticus biofilm poses a serious threat to food safety and human health. However, there is limited knowledge of transcriptional regulatory mechanism during the biofilm formation of this organism. Hence, the RNA sequencing technique was employed to compare the differences in transcriptome profiles between planktonic and biofilm state of V. parahaemolyticus ATCC33847 in this study. Collections of mRNA from planktonic and biofilm cells cultured at 25°C for 36 h were sequenced by studying their biological characteristics. The results showed that there were significant differences in the expression levels of 956 genes in biofilms compared with planktonic cells. These differences suggested that two-component regulatory system (TCS) and quorum sensing (QS) regulated V. parahaemolyticus biofilm formation by affecting important factors such as flagellar motility, Extracellular polymeric substance (EPS) secretion, tripartite ATP-independent (TRAP) transport system and ATP binding cassette (ABC) transport system. The present work in transcriptomics serves as a basis for future studies examining the complex network systems that regulate bacterial biofilm formation.}, } @article {pmid35899044, year = {2022}, author = {Didehdar, M and Chegini, Z and Tabaeian, SP and Razavi, S and Shariati, A}, title = {Cinnamomum: The New Therapeutic Agents for Inhibition of Bacterial and Fungal Biofilm-Associated Infection.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {930624}, pmid = {35899044}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents/chemistry ; Biofilms ; *Cinnamomum/chemistry/metabolism ; Cyclic GMP ; Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {Due to the potent antibacterial properties of Cinnamomum and its derivatives, particularly cinnamaldehyde, recent studies have used these compounds to inhibit the growth of the most prevalent bacterial and fungal biofilms. By inhibiting flagella protein synthesis and swarming motility, Cinnamomum could suppress bacterial attachment, colonization, and biofilm formation in an early stage. Furthermore, by downregulation of Cyclic di-guanosine monophosphate (c-di-GMP), biofilm-related genes, and quorum sensing, this compound suppresses intercellular adherence and accumulation of bacterial cells in biofilm and inhibits important bacterial virulence factors. In addition, Cinnamomum could lead to preformed biofilm elimination by enhancing membrane permeability and the disruption of membrane integrity. Moreover, this substance suppresses the Candida species adherence to the oral epithelial cells, leading to the cell wall deformities, damage, and leakages of intracellular material that may contribute to the established Candida's biofilm elimination. Therefore, by inhibiting biofilm maturation and destroying the external structure of biofilm, Cinnamomum could boost antibiotic treatment success in combination therapy. However, Cinnamomum has several disadvantages, such as poor solubility in aqueous solution, instability, and volatility; thus, the use of different drug-delivery systems may resolve these limitations and should be further considered in future investigations. Overall, Cinnamomum could be a promising agent for inhibiting microbial biofilm-associated infection and could be used as a catheter and other medical materials surface coatings to suppress biofilm formation. Nonetheless, further in vitro toxicology analysis and animal experiments are required to confirm the reported molecular antibiofilm effect of Cinnamomum and its derivative components against microbial biofilm.}, } @article {pmid35897636, year = {2022}, author = {Chen, H and Yan, CH and Zhan, YF and Geng, LT and Zhu, LL and Gong, LC and Wang, J}, title = {Boron Derivatives Accelerate Biofilm Formation of Recombinant Escherichia coli via Increasing Quorum Sensing System Autoinducer-2 Activity.}, journal = {International journal of molecular sciences}, volume = {23}, number = {15}, pages = {}, pmid = {35897636}, issn = {1422-0067}, support = {21676130//National Natural Science Foundation of China/ ; BRA2019281//333 High-level Talent Training Project of Jiangsu Province/ ; 16KJA530002//Key Project of University Science Research 383 of Jiangsu Province/ ; }, mesh = {Bacteria/metabolism ; Bacterial Proteins/metabolism ; Biofilms ; Boron ; *Escherichia coli/metabolism ; Homoserine/pharmacology ; Lactones/metabolism/pharmacology ; *Quorum Sensing/genetics ; }, abstract = {Boron is an essential element for autoinducer-2 (AI-2) synthesis of quorum sensing (QS) system, which affects bacterial collective behavior. As a living biocatalyst, biofilms can stably catalyze the activity of intracellular enzymes. However, it is unclear how boron affects biofilm formation in E. coli, particularly recombinant E. coli with intracellular enzymes. This study screened different boron derivatives to explore their effect on biofilm formation. The stress response of biofilm formation to boron was illuminated by analyzing AI-2 activity, extracellular polymeric substances (EPS) composition, gene expression levels, etc. Results showed that boron derivatives promote AI-2 activity in QS system. After treatment with H3BO3 (0.6 mM), the AI-2 activity increased by 65.99%, while boron derivatives increased the biomass biofilms in the order H3BO3 > NaBO2 > Na2B4O7 > NaBO3. Moreover, treatment with H3BO3 (0.6 mM) increased biomass by 88.54%. Meanwhile, AI-2 activity had a linear correlation with polysaccharides and protein of EPS at 0−0.6 mM H3BO3 and NaBO2 (R2 > 0.8). Furthermore, H3BO3 upregulated the expression levels of biofilm formation genes, quorum sensing genes, and flagellar movement genes. These findings demonstrated that boron promoted biofilm formation by upregulating the expression levels of biofilm-related genes, improving the QS system AI-2 activity, and increasing EPS secretion in E. coli.}, } @article {pmid35897517, year = {2022}, author = {Liu, Y and Li, W and Tao, C and Zhao, J and Zhang, H and Miao, L and Pang, Y and Hou, J}, title = {Distinct Responses of Biofilm Carbon Metabolism to Nanoplastics with Different Surface Modifications.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {15}, pages = {}, pmid = {35897517}, issn = {1660-4601}, mesh = {Biofilms ; Carbon ; Ecosystem ; Microplastics/toxicity ; *Nanoparticles/chemistry/toxicity ; Polystyrenes/chemistry ; *Water Pollutants, Chemical/chemistry ; }, abstract = {Recently, there is an increasing concern regarding the toxicity of nanoplastics (NPs) on freshwater organisms. However, knowledge about the potential impacts of NPs with different surface modification on freshwater biofilms is still very limited. In this research, biofilms were cultured in lab and exposed to nano polystyrene (PS) beads: non-functionalized PS NPs, PS-COOH NPs, and the carbon source utilization of biofilms were measured by BIOLOG ECO microplates. The results showed that both two types of PS NPs significantly reduced the total carbon metabolic activity of biofilms, compared with the controls, whereas the carbon metabolic rate increased notably, especially for the PS-COOH NPs treatments at day 14. Moreover, results from six categories of carbon sources analysis suggested that PS NPs with different surface chemical properties exhibit distinct effects on the carbon utilization of biofilms, and the divergent changes of the specific carbon source category were observed at day 21 from the two PS NPs treatments. In addition, the metabolic functional diversity of biofilms were not altered by the PS NPs treatments. These findings highlighted that chemical properties of NPs play an important role in the toxic effects on the carbon metabolism activities of the biofilms. This study offers new insights that nanoplastics of different chemical characteristics have the ability to affect the microbial-mediated carbon cycling process in aquatic ecosystems.}, } @article {pmid35893563, year = {2022}, author = {Deng, Y and Wang, SY}, title = {Sorption of Cellulases in Biofilm Enhances Cellulose Degradation by Bacillus subtilis.}, journal = {Microorganisms}, volume = {10}, number = {8}, pages = {}, pmid = {35893563}, issn = {2076-2607}, abstract = {Biofilm commonly forms on the surfaces of cellulosic biomass but its roles in cellulose degradation remain largely unexplored. We used Bacillus subtilis to study possible mechanisms and the contributions of two major biofilm components, extracellular polysaccharides (EPS) and TasA protein, to submerged biofilm formation on cellulose and its degradation. We found that biofilm produced by B. subtilis is able to absorb exogenous cellulase added to the culture medium and also retain self-produced cellulase within the biofilm matrix. The bacteria that produced more biofilm degraded more cellulose compared to strains that produced less biofilm. Knockout strains that lacked both EPS and TasA formed a smaller amount of submerged biofilm on cellulose than the wild-type strain and also degraded less cellulose. Imaging of biofilm on cellulose suggests that bacteria, cellulose, and cellulases form cellulolytic biofilm complexes that facilitate synergistic cellulose degradation. This study brings additional insight into the important functions of biofilm in cellulose degradation and could potentiate the development of biofilm-based technology to enhance biomass degradation for biofuel production.}, } @article {pmid35893558, year = {2022}, author = {Durand, BARN and Pouget, C and Magnan, C and Molle, V and Lavigne, JP and Dunyach-Remy, C}, title = {Bacterial Interactions in the Context of Chronic Wound Biofilm: A Review.}, journal = {Microorganisms}, volume = {10}, number = {8}, pages = {}, pmid = {35893558}, issn = {2076-2607}, abstract = {Chronic wounds, defined by their resistance to care after four weeks, are a major concern, affecting millions of patients every year. They can be divided into three types of lesions: diabetic foot ulcers (DFU), pressure ulcers (PU), and venous/arterial ulcers. Once established, the classical treatment for chronic wounds includes tissue debridement at regular intervals to decrease biofilm mass constituted by microorganisms physiologically colonizing the wound. This particular niche hosts a dynamic bacterial population constituting the bed of interaction between the various microorganisms. The temporal reshuffle of biofilm relies on an organized architecture. Microbial community turnover is mainly associated with debridement (allowing transitioning from one major representant to another), but also with microbial competition and/or collaboration within wounds. This complex network of species and interactions has the potential, through diversity in antagonist and/or synergistic crosstalk, to accelerate, delay, or worsen wound healing. Understanding these interactions between microorganisms encountered in this clinical situation is essential to improve the management of chronic wounds.}, } @article {pmid35892912, year = {2022}, author = {Asma, ST and Imre, K and Morar, A and Herman, V and Acaroz, U and Mukhtar, H and Arslan-Acaroz, D and Shah, SRA and Gerlach, R}, title = {An Overview of Biofilm Formation-Combating Strategies and Mechanisms of Action of Antibiofilm Agents.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {8}, pages = {}, pmid = {35892912}, issn = {2075-1729}, abstract = {Biofilm formation on surfaces via microbial colonization causes infections and has become a major health issue globally. The biofilm lifestyle provides resistance to environmental stresses and antimicrobial therapies. Biofilms can cause several chronic conditions, and effective treatment has become a challenge due to increased antimicrobial resistance. Antibiotics available for treating biofilm-associated infections are generally not very effective and require high doses that may cause toxicity in the host. Therefore, it is essential to study and develop efficient anti-biofilm strategies that can significantly reduce the rate of biofilm-associated healthcare problems. In this context, some effective combating strategies with potential anti-biofilm agents, including plant extracts, peptides, enzymes, lantibiotics, chelating agents, biosurfactants, polysaccharides, organic, inorganic, and metal nanoparticles, etc., have been reviewed to overcome biofilm-associated healthcare problems. From their extensive literature survey, it can be concluded that these molecules with considerable structural alterations might be applied to the treatment of biofilm-associated infections, by evaluating their significant delivery to the target site of the host. To design effective anti-biofilm molecules, it must be assured that the minimum inhibitory concentrations of these anti-biofilm compounds can eradicate biofilm-associated infections without causing toxic effects at a significant rate.}, } @article {pmid35892383, year = {2022}, author = {Attallah, NGM and Al-Fakhrany, OM and Elekhnawy, E and Hussein, IA and Shaldam, MA and Altwaijry, N and Alqahtani, MJ and Negm, WA}, title = {Anti-Biofilm and Antibacterial Activities of Cycas media R. Br Secondary Metabolites: In Silico, In Vitro, and In Vivo Approaches.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {8}, pages = {}, pmid = {35892383}, issn = {2079-6382}, support = {rincess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R89//Princess Nourah bint Abdulrahman University/ ; }, abstract = {Enterococcus species possess many virulence factors that have an essential role in exacerbating the infections caused by them. The current study aimed to evaluate the effect of the secondary metabolites ginkgetin (GINK) and sotetsuflavone (SOTE), isolated from Cycas media R. Br dichloromethane fraction, on Enterococcus faecalis (E. faecalis) isolates for the first time. The antibacterial and antivirulence activities of the isolated compounds were investigated using docking studies and in vitro by determination of the minimum inhibitory concentrations (MICs). Additionally, flow cytometry and scanning electron microscope (SEM) were utilized to assess the effect of SOTE on the tested bacteria. Moreover, crystal violet assay and qRT-PCR were used to test the effect of SOTE on the biofilm-forming ability of E. faecalis isolates. In addition, a systemic infection model was utilized in vivo to investigate the antibacterial activity of SOTE. We found that both GINK and SOTE showed a good affinity for the five proteins enrolled in the virulence of E. faecalis, with SOTE being the highest, suggesting the possible mechanisms for the antivirulence activity of both ligands. In addition, SOTE exhibited a higher antibacterial activity than GINK, as the values of the MICs of SOTE were lower than those of GINK. Thus, we performed the in vitro and in vivo assays on SOTE. However, they did not exhibit any significant variations (p > 0.05) in the membrane depolarization of E. faecalis isolates. Moreover, as evaluated by SEM, SOTE caused distortion and deformation in the treated cells. Regarding its impact on the biofilm formation, it inhibited the biofilm-forming ability of the tested isolates, as determined by crystal violet assay and qRT-PCR. The in vivo experiment revealed that SOTE resulted in a reduction of the inflammation of the liver and spleen with an increase in the survival rate. SOTE also improved the liver-function tests and decreased tumor necrosis factor-alpha using immunostaining and the inflammation markers, interleukins (IL-1β and IL-6), using ELISA. Thus, we can conclude that SOTE could be a promising compound that should be investigated in future preclinical and clinical studies.}, } @article {pmid35890430, year = {2022}, author = {da Fonseca, STD and Teixeira, TR and Ferreira, JMS and Lima, LARDS and Luyten, W and Castro, AHF}, title = {Flavonoid-Rich Fractions of Bauhinia holophylla Leaves Inhibit Candida albicans Biofilm Formation and Hyphae Growth.}, journal = {Plants (Basel, Switzerland)}, volume = {11}, number = {14}, pages = {}, pmid = {35890430}, issn = {2223-7747}, support = {Finance Code 001//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; 444907/2014-9//National Council for Scientific and Technological Development/ ; CRA - APQ-01347-14//Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; }, abstract = {This study evaluated the effect of the extract and fractions of Bauhinia holophylla on Candida albicans planktonic growth, biofilm formation, mature biofilm, and hyphae growth. Three C. albicans strains (SC5314, ATCC 18804, and ATCC 10231) were tested. The crude extract and the fractions were obtained by exhaustive percolation and liquid-liquid partition, respectively. Phytochemical analyses of B. holophylla extract and fractions were performed using high-performance liquid chromatography coupled with a diode-array detector and mass spectrometry (HPLC-DAD-MS). A microdilution assay was used to evaluate the effect of the B. holophylla extract and fractions on C. albicans planktonic growth, and crystal violet staining was used to measure the total biomass of the biofilm. Hyphae growth was analyzed using light microscopy. Thirteen flavonoids were identified, with a predominance of the flavonol-3-O-glycoside type based on quercetin, myricetin, and kaempferol. Flavonoid-rich fractions of B. holophylla leaves displayed antifungal activity and inhibited both biofilm formation and hyphae growth in all the tested strains, but were not effective on C. albicans planktonic growth and mature biofilm. This study indicates that flavonoid-rich fractions from B. holophylla leaves interfere with the virulence of Candida species and support the use of Bauhinia spp. in folk medicine to treat infections.}, } @article {pmid35890251, year = {2022}, author = {Seredin, P and Goloshchapov, D and Kashkarov, V and Nesterov, D and Ippolitov, Y and Ippolitov, I and Vongsvivut, J}, title = {Effect of Exo/Endogenous Prophylaxis Dentifrice/Drug and Cariogenic Conditions of Patient on Molecular Property of Dental Biofilm: Synchrotron FTIR Spectroscopic Study.}, journal = {Pharmaceutics}, volume = {14}, number = {7}, pages = {}, pmid = {35890251}, issn = {1999-4923}, support = {21-15-00026//Russian Science Foundation/ ; 075-15-2021-1351//Ministry of Science and Higher Education of Russia/ ; }, abstract = {(1) Objectives: This study is the first one to investigate the molecular composition of the dental biofilm during the exogenous and endogenous prophylaxis stages (use of dentifrice/drug) of individuals with different cariogenic conditions using molecular spectroscopy methods. (2) Materials and Methods: The study involved 100 participants (50 males and 50 females), aged 18-25 years with different caries conditions. Biofilm samples were collected from the teeth surface of all participants. The molecular composition of biofilms was investigated using synchrotron infrared microspectroscopy. Changes in the molecular composition were studied through calculation and analysis of ratios between organic and mineral components of biofilm samples. (3) Results: Based on the data obtained by synchrotron FTIR, calculations of organic and mineral component ratios, and statistical analysis of the data, we were able to assess changes occurring in the molecular composition of the dental biofilm. Variations in the phosphate/protein/lipid, phosphate/mineral, and phospholipid/lipid ratios and the presence of statistically significant intra- and inter-group differences in these ratios indicate that the mechanisms of ion adsorption, compounds and complexes arriving from oral fluid into dental biofilm during exo/endogenous prophylaxis, differ for patients in norm and caries development. (4) Conclusions: The conformational environment and charge interaction in the microbiota and the electrostatic state of the biofilm protein network in patients with different cariogenic conditions play an important role. (5) Clinical Significance: Understanding the changes that occur in the molecular composition of the dental biofilm in different oral homeostasis conditions will enable successful transition to a personalised approach in dentistry and high-tech healthcare.}, } @article {pmid35890182, year = {2022}, author = {Ugalde-Arbizu, M and Aguilera-Correa, JJ and Mediero, A and Esteban, J and Páez, PL and San Sebastian, E and Gómez-Ruiz, S}, title = {Hybrid Nanosystems Based on Nicotinate-Functionalized Mesoporous Silica and Silver Chloride Nanoparticles Loaded with Phenytoin for Preventing Pseudomonas aeruginosa Biofilm Development.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {15}, number = {7}, pages = {}, pmid = {35890182}, issn = {1424-8247}, support = {RTI2018-094322-B-I00//Ministerio de Ciencia e Innovación/ ; PID2021-125547OB-I00//Ministerio de Ciencia e Innovación/ ; GIC18/143//University of the Basque Country/ ; CP15/00053//Instituto de Salud Carlos III/ ; }, abstract = {Pseudomonas aeruginosa (PA) is one of the most common bacteria isolated from chronic wounds and burns. Its treatment is a challenge due to antimicrobial drug resistance and biofilm formation. In this context, this study aimed to perform the synthesis and full characterization of hybrid nanosystems based on mesoporous silica nanoparticles (MSNs) functionalized with a nicotinic ligand and silver chloride nanoparticles, both phenytoin sodium (Ph)-loaded and unloaded, to evaluate the antibacterial properties against three different strains of PA (including two clinical strains) in a planktonic state and as biofilms. Ph is a well-known proliferative agent, which was incorporated into the hybrid nanomaterials to obtain an effective material for tissue healing and prevention of infection caused by PA. The Ph-loaded materials promoted a quasi-complete inhibition of bacterial growth in wound-like medium and biofilm development, with values of 99% and 96%, respectively, with selectivity indices above the requirements for drugs to become promising agents for the topic preventive treatment of chronic wounds and burns.}, } @article {pmid35889986, year = {2022}, author = {Sisto, F and Carradori, S and D'Alessandro, S and Santo, N and Lattuada, N and Haynes, RK and Taramelli, D and Grande, R}, title = {In Vitro Activity of the Arylaminoartemisinin GC012 against Helicobacter pylori and Its Effects on Biofilm.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35889986}, issn = {2076-0817}, support = {//University of Milan/ ; }, abstract = {This study evaluated the in vitro activity of the arylaminoartemisinin GC012, readily obtained from dihydroartemisinin (DHA), against clinical strains of Helicobacter pylori (H. pylori) with different antibiotic susceptibilities in the planktonic and sessile state. The activity was assessed in terms of bacteriostatic and bactericidal potential. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method. After treatment with GC012, all bacterial strains showed significantly lower MIC and MBC values compared to those of DHA. The effect of combination of GC012 with antibiotics was examined using the checkerboard method. GC012 displayed synergistic interactions with metronidazole, clarithromycin, and amoxicillin in all the strains. The antibiofilm activity was evaluated via crystal violet staining, AlamarBlue[®] assay, colony-forming unit count, and fluorescence microscopy. At ½ MIC and ¼ MIC concentration, both GC012 and DHA inhibited biofilm formation, but only GC012 showed a minimal biofilm eradication concentration (MBEC) on mature biofilm. Furthermore, both compounds induced structural changes in the bacterial membrane, as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is thereby demonstrated that GC012 has the potential to be efficacious against H. pylori infection.}, } @article {pmid35889378, year = {2022}, author = {Švarcová, K and Hofmeisterová, L and Švecová, B and Šilha, D}, title = {In Vitro Activity of Water Extracts of Olive Oil against Planktonic Cells and Biofilm Formation of Arcobacter-like Species.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {14}, pages = {}, pmid = {35889378}, issn = {1420-3049}, mesh = {*Arcobacter ; Biofilms ; Olive Oil/analysis ; Phenols/analysis/pharmacology ; Plankton ; Plant Oils/pharmacology ; Water ; }, abstract = {Extra-virgin olive oils contain many bioactive substances that are phenolic compounds. The survival of Arcobacter-like strains in non-buffered (WEOO) and buffered (BEOO) extracts of olive oils were studied. Time kill curves of different strains were measured in the environment of olive oil extracts of different grades. The activity of the extracts was also monitored for biofilm formation using the Christensen method. In vitro results revealed that extra-virgin olive oil extracts exhibited the strongest antimicrobial effects, especially non-buffered extracts, which exhibited strain inhibition after only 5 min of exposure. The weakest inhibitory effects were observed for olive oil extracts. A decrease in biofilm formation was observed in the environment of higher WEOO concentrations, although at lower concentrations of extracts, increased biofilm formation occurred due to stress conditions. The dialdehydic forms of oleuropein derivatives, hydroxytyrosol, and tyrosol were the main compounds detected by HPLC-CoulArray. The results indicate that not all olive oils had a similar bactericidal effect, and that bioactivity primarily depended on the content of certain phenolic compounds.}, } @article {pmid35889057, year = {2022}, author = {Xu, S and Cao, Q and Liu, Z and Chen, J and Yan, P and Li, B and Xu, Y}, title = {Transcriptomic Analysis Reveals the Role of tmRNA on Biofilm Formation in Bacillus subtilis.}, journal = {Microorganisms}, volume = {10}, number = {7}, pages = {}, pmid = {35889057}, issn = {2076-2607}, support = {JCYJ20210324093409025//Shenzhen Science and Technology Program/ ; 2020A1515011117//Guangdong Natural Science Foundation/ ; }, abstract = {Bacillus strains are widely distributed in terrestrial and marine environments, and some of them are used as biocontrol organisms for their biofilm-formation ability. In Bacillus subtilis, biofilm formation is fine-tuned by a complex network, a clear understanding of which still requires study. In bacteria, tmRNA, encoded by the ssrA gene, catalyzes trans-translation that can rescue ribosomes stalled on mRNA transcripts lacking a functional stop codon. tmRNA also affects physiological bioprocesses in some bacteria. In this study, we constructed a ssrA mutant in B. subtilis and found that the biofilm formation in the ssrA mutant was largely impaired. Moreover, we isolated a biofilm-formation suppressor of ssrA, in which the biofilm formation was restored to a level even stronger than that in the wild type. We further performed RNAseq assays with the wild type, ssrA mutant, and suppressor of ssrA for comparisons of their transcriptomes. By analyzing the transcriptomic data, we predicted the possible functions of some differentially expressed genes (DEGs) in the tmRNA regulation of biofilm formation in B. subtilis. Finally, we found that the overexpression of two DEGs, acoA and yhjR, could restore the biofilm formation in the ssrA mutant, indicating that AcoA and YhjR were immediate regulators involved in the tmRNA regulatory web controlling biofilm formation in B. subtilis. Our data can improve the knowledge about the molecular network involved in Bacillus biofilm formation and provide new targets for manipulation of Bacillus biofilms for future investigation.}, } @article {pmid35889016, year = {2022}, author = {Rugaie, OA and Abdellatif, AAH and El-Mokhtar, MA and Sabet, MA and Abdelfattah, A and Alsharidah, M and Aldubaib, M and Barakat, H and Abudoleh, SM and Al-Regaiey, KA and Tawfeek, HM}, title = {Retardation of Bacterial Biofilm Formation by Coating Urinary Catheters with Metal Nanoparticle-Stabilized Polymers.}, journal = {Microorganisms}, volume = {10}, number = {7}, pages = {}, pmid = {35889016}, issn = {2076-2607}, support = {QU-IF-1-4-1//Deputyship for Research & Innovation, Ministry of Education, Saudi Arabia/ ; }, abstract = {Urinary catheter infections remain an issue for many patients and can complicate their health status, especially for individuals who require long-term catheterization. Catheters can be colonized by biofilm-forming bacteria resistant to the administered antibiotics. Therefore, this study aimed to investigate the efficacy of silver nanoparticles (AgNPs) stabilized with different polymeric materials generated via a one-step simple coating technique for their ability to inhibit biofilm formation on urinary catheters. AgNPs were prepared and characterized to confirm their formation and determine their size, charge, morphology, and physical stability. Screening of the antimicrobial activity of nanoparticle formulations and determining minimal inhibitory concentration (MIC) and their cytotoxicity against PC3 cells were performed. Moreover, the antibiofilm activity and efficacy of the AgNPs coated on the urinary catheters under static and flowing conditions were examined against a clinical isolate of Escherichia coli. The results showed that the investigated polymers could form physically stable AgNPs, especially those prepared using polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC). Preliminary screening and MIC determinations suggested that the AgNPs-EC and AgNPs-PVP had superior antibacterial effects against E. coli. AgNPs-EC and AgNPs-PVP inhibited biofilm formation to 58.2% and 50.8% compared with AgNPs-PEG, silver nitrate solution and control samples. In addition, coating urinary catheters with AgNPs-EC and AgNPs-PVP at concentrations lower than the determined IC50 values significantly (p < 0.05; t-test) inhibited bacterial biofilm formation compared with noncoated catheters under both static and static and flowing conditions using two different types of commercial Foley urinary catheters. The data obtained in this study provide evidence that AgNP-coated EC and PVP could be useful as potential antibacterial and antibiofilm catheter coating agents to prevent the development of urinary tract infections caused by E. coli.}, } @article {pmid35888978, year = {2022}, author = {Di Domenico, EG and Oliva, A and Guembe, M}, title = {The Current Knowledge on the Pathogenesis of Tissue and Medical Device-Related Biofilm Infections.}, journal = {Microorganisms}, volume = {10}, number = {7}, pages = {}, pmid = {35888978}, issn = {2076-2607}, support = {MSII18/00008//Instituto de Salud Carlos III/ ; }, abstract = {Biofilm is the trigger for the majority of infections caused by the ability of microorganisms to adhere to tissues and medical devices. Microbial cells embedded in the biofilm matrix are highly tolerant to antimicrobials and escape the host immune system. Thus, the refractory nature of biofilm-related infections (BRIs) still represents a great challenge for physicians and is a serious health threat worldwide. Despite its importance, the microbiological diagnosis of a BRI is still difficult and not routinely assessed in clinical microbiology. Moreover, biofilm bacteria are up to 100-1000 times less susceptible to antibiotics than their planktonic counterpart. Consequently, conventional antibiograms might not be representative of the bacterial drug susceptibility in vivo. The timely recognition of a BRI is a crucial step to directing the most appropriate biofilm-targeted antimicrobial strategy.}, } @article {pmid35887498, year = {2022}, author = {AlJindan, R and AlEraky, DM}, title = {Silver Nanoparticles: A Promising Antifungal Agent against the Growth and Biofilm Formation of the Emergent Candida auris.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {7}, pages = {}, pmid = {35887498}, issn = {2309-608X}, abstract = {Candida auris is a globally-emerging pathogen that is correlated to nosocomial infections and high mortality rates, causing major outbreaks in hospitals and serious public health concerns worldwide. This study investigated the antifungal activity of silver nanoparticles (AgNPs) on clinical isolates of C. auris. A total of eight clinical isolates were collected from blood, urine, ear swab, and groin. C. auris was confirmed by MALDI-TOF MS, and gene sequencing. All isolates confirmed as C. auris were subjected to antimicrobial agents, including amphotericin B, fluconazole, caspofungin, voriconazole, micafungin, and flucytosine. A serial dilution of a silver nanoparticles solution was prepared to test antifungal susceptibility testing under planktonic conditions. Moreover, an antibiofilm activity assay was determined using a colony-forming assay and a cell viability assay by a live−dead yeast kit. Significant antifungal and antibiofilm activity of AgNPs was detected against all isolates; MIC was <6.25 μg/mL, the range of MFC was from 6.25 to 12.5 μg/mL for all isolates, and the highest value of IC50 was 3.2 μg/mL. Silver nanomaterials could represent a possible antimicrobial agent to prevent outbreaks caused by C. auris infections.}, } @article {pmid35886960, year = {2022}, author = {Żebrowska, J and Żołnierkiewicz, O and Ponikowska, M and Puchalski, M and Krawczun, N and Makowska, J and Skowron, P}, title = {Cloning and Characterization of a Thermostable Endolysin of Bacteriophage TP-84 as a Potential Disinfectant and Biofilm-Removing Biological Agent.}, journal = {International journal of molecular sciences}, volume = {23}, number = {14}, pages = {}, pmid = {35886960}, issn = {1422-0067}, support = {MINIATURA3/2019/03/X/NZ1/01903//National Science Center/ ; TECHMATSTRATEG2/410747/11/NCBR/2019//National Center for Reseach and Dvelopement/ ; }, mesh = {Bacteria/metabolism ; *Bacteriophages/metabolism ; Biofilms ; Biological Factors ; Cloning, Molecular ; *Disinfectants ; Endopeptidases/genetics/metabolism/pharmacology ; Peptidoglycan/metabolism ; }, abstract = {The obligatory step in the life cycle of a lytic bacteriophage is the release of its progeny particles from infected bacterial cells. The main barrier to overcome is the cell wall, composed of crosslinked peptidoglycan, which counteracts the pressure prevailing in the cytoplasm and protects the cell against osmotic lysis and mechanical damage. Bacteriophages have developed two strategies leading to the release of progeny particles: the inhibition of peptidoglycan synthesis and enzymatic cleavage by a bacteriophage-coded endolysin. In this study, we cloned and investigated the TP84_28 endolysin of the bacteriophage TP-84, which infects thermophilic Geobacillus stearothermophilus, determined the enzymatic characteristics, and initially evaluated the endolysin application as a non-invasive agent for disinfecting surfaces, including those exposed to high temperatures. Both the native and recombinant TP84_28 endolysins, obtained through the Escherichia coli T7-lac expression system, are highly thermostable and retain trace activity after incubation at 100 °C for 30 min. The proteins exhibit strong bacterial wall digestion activity up to 77.6 °C, decreasing to marginal activity at ambient temperatures. We assayed the lysis of various types of bacteria using TP84_28 endolysins: Gram-positive, Gram-negative, encapsulated, and pathogenic. Significant lytic activity was observed on the thermophilic and mesophilic Gram-positive bacteria and, to a lesser extent, on the thermophilic and mesophilic Gram-negative bacteria. The thermostable TP84_28 endolysin seems to be a promising mild agent for disinfecting surfaces exposed to high temperatures.}, } @article {pmid35886209, year = {2022}, author = {Zuo, J and Fan, Q and Li, J and Liu, B and Xue, B and Zhang, X and Yi, L and Wang, Y}, title = {Sub-Inhibitory Concentrations of Amoxicillin and Tylosin Affect the Biofilm Formation and Virulence of Streptococcus suis.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {14}, pages = {}, pmid = {35886209}, issn = {1660-4601}, mesh = {Amoxicillin/pharmacology ; Animals ; Biofilms ; Disease Models, Animal ; Mice ; *Streptococcal Infections/microbiology/veterinary ; *Streptococcus suis/genetics ; Tylosin/pharmacology ; Virulence ; }, abstract = {Streptococcus suis (S. suis) can form a protective biofilm during infection and lead to prolonged disease. Oral antibiotics are often used for treatment in clinical practice, but sub-inhibitory concentration levels often exist due to low oral absorption rate, resulting in disease deterioration. The purpose of this study was to investigate the effects of Amoxicillin and Tylosin on the biofilm formation and virulence of S. suis HA9801 at sub-inhibitory concentration. We first determined that the test groups (1/4MIC Amoxicillin and Tylosin) could significantly increase the amount of biofilm formation without affecting bacterial growth. The LD50 value of the test groups was significantly higher than that of the control group in the mouse infection model. In the mouse infection model, the LD50 value of the experimental group was significantly increased, but the tissue bacterial load was significantly decreased. Further RT-PCR analysis showed that the expression levels of virulence-related genes in the experimental group were significantly reduced. Our study suggests that both Amoxicillin and Tylosin at sub-inhibitory concentrations could enhance the biofilm formation ability of S. suis HA9801 and reduce its virulence to form persistent infection.}, } @article {pmid35884920, year = {2022}, author = {Jailani, A and Ahmed, B and Lee, JH and Lee, J}, title = {Inhibition of Agrobacterium tumefaciens Growth and Biofilm Formation by Tannic Acid.}, journal = {Biomedicines}, volume = {10}, number = {7}, pages = {}, pmid = {35884920}, issn = {2227-9059}, support = {2014R1A6A1031189//National Research Foundation of Korea/ ; 2021R1I1A3A04037486//National Research Foundation of Korea/ ; 2021R1A2C1008368//National Research Foundation of Korea/ ; }, abstract = {Agrobacterium tumefaciens underlies the pathogenesis of crown gall disease and is characterized by tumor-like gall formation on the stems and roots of a wide variety of economically important plant species. The bacterium initiates infection by colonizing and forming biofilms on plant surfaces, and thus, novel compounds are required to prevent its growth and biofilm formation. In this study, we investigated the ability of tannic acid, which is ubiquitously present in woody plants, to specifically inhibit the growth and biofilm formation of A. tumefaciens. Tannic acid showed antibacterial activity and significantly reduced the biofilm formation on polystyrene and on the roots of Raphanus sativus as determined by 3D bright-field and scanning electron microscopy (SEM) images. Furthermore, tannic acid dose-dependently reduced the virulence features of A. tumefaciens, which are swimming motility, exopolysaccharide production, protease production, and cell surface hydrophobicity. Transcriptional analysis of cells (Abs600 nm = 1.0) incubated with tannic acid for 24 h at 30 °C showed tannic acid most significantly downregulated the exoR gene, which is required for adhesion to surfaces. Tannic acid at 100 or 200 µg/mL limited the iron supply to A. tumefaciens and similarly reduced the biofilm formation to that performed by 0.1 mM EDTA. Notably, tannic acid did not significantly affect R. sativus germination even at 400 µg/mL. The findings of this study suggest that tannic acid has the potential to prevent growth and biofilm formation by A. tumefaciens and thus infections resulting from A. tumefaciens colonization.}, } @article {pmid35884284, year = {2022}, author = {Rakhimbekova, A and Kudaibergenov, B and Moldabay, D and Zharylgap, A and Ajunwa, OM and Marsili, E and Tosi, D}, title = {Biofilm Detection by a Fiber-Tip Ball Resonator Optical Fiber Sensor.}, journal = {Biosensors}, volume = {12}, number = {7}, pages = {}, pmid = {35884284}, issn = {2079-6374}, support = {091019CRP2117//Nazarbayev University/ ; 021220CRP0522//Nazarbayev University/ ; 240919FD3908//Nazarbayev University/ ; }, mesh = {Bacteria ; Biofilms ; *Biosensing Techniques ; *Optical Fibers ; Pseudomonas aeruginosa ; Refractometry ; }, abstract = {Bacterial biofilms are one of the most important challenges that modern medicine faces due to the difficulties of diagnosis, antibiotic resistance, and protective mechanisms against aggressive environments. For these reasons, methods that ensure the inexpensive and rapid or real-time detection of biofilm formation on medical devices are needed. This study examines the possibilities of using optical- and fiber-based biosensors to detect and analyze early bacterial biofilms. In this study, the biofilm-forming model organism Pseudomonas aeruginosa was inoculated on the surface of the optical sensor and allowed to attach for 2 h. The biosensors were made by a fiber-tip ball resonator, fabricated through a CO2 laser splicer on a single-mode fiber, forming a weak reflective spectrum. An optical backscatter reflectometer was used to measure the refractive index detected by the sensors during different growth periods. The early biofilm concentration was determined by crystal violet (CV) binding assay; however, such a concentration was lower than the detection limit of this assay. This work presents a new approach of biofilm sensing in the early attachment stage with a low limit of detection up to 10[-4] RIU (refractive index units) or 35 ± 20 × 10[3] CFU/mL (colony formed units).}, } @article {pmid35884213, year = {2022}, author = {Wences, M and Wolf, ER and Li, C and Singh, N and Bah, N and Tan, X and Huang, Y and Bulman, ZP}, title = {Combatting Planktonic and Biofilm Populations of Carbapenem-Resistant Acinetobacter baumannii with Polymyxin-Based Combinations.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884213}, issn = {2079-6382}, support = {KL2 TR002002/TR/NCATS NIH HHS/United States ; 2021//Riback Summer Research Award, UIC/ ; }, abstract = {Carbapenem-resistant Acinetobacter baumannii (CRAB) can cause serious infections that are associated with high mortality rates. During the course of an infection, many CRAB isolates are able to form biofilms, which are recalcitrant to several antibiotics and can be difficult to treat. Polymyxin-based regimens are a first-line treatment option for CRAB infections, but they have not been optimized against both planktonic and biofilm phases of growth. The objective of this study was to identify polymyxin-based combinations that are active against planktonic and biofilm populations of CRAB. Four CRAB isolates (meropenem MICs: 8-256 mg/L) capable of forming biofilms were used in each experiment. The activities of polymyxin B alone and in combination with ampicillin/sulbactam, meropenem, minocycline, and rifampin were assessed using time-kill assays, with the CRAB isolates grown in planktonic and biofilm phases. Viable colony counts were used to detect the bactericidal activity and synergy of the antibiotic combinations. Against the planktonic populations, polymyxin B combined with meropenem, minocycline, ampicillin/sulbactam, and rifampin caused 3.78, -0.15, 4.38, and 3.23 mean log10 CFU/mL reductions against all isolates at 24 h, respectively. Polymyxin B combined with meropenem, ampicillin/sulbactam, or rifampin was synergistic against 75-100% (3/4 or 4/4) of CRAB isolates. Against biofilms, polymyxin B combined with meropenem, minocycline, ampicillin/sulbactam, and rifampin caused 1.86, 1.01, 0.66, and 3.55 mean log10 CFU/mL reductions against all isolates at 24 h, respectively. Only the combination of polymyxin B and rifampin retained bactericidal activity or synergy against any of the isolates when grown as biofilms (50% of isolates). The combination of polymyxin B and rifampin may be promising for CRAB infections that have planktonic and biofilm populations present.}, } @article {pmid35884204, year = {2022}, author = {Raorane, CJ and Shastri, D and Parveen, AS and Haldhar, R and Raj, V and Kim, SC}, title = {Grafted Chitosan-Hyaluronic Acid (CS-g-poly (MA-co-AN) HA) Complex Inhibits Fluconazole-Resistant Candida albicans Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884204}, issn = {2079-6382}, support = {S3060516//Technology development Program/ ; 2020R1I1A3052258//National Research Foundation of Korea/ ; }, abstract = {Fungal resistance that leads to the failure of drug therapy due to biofilm development is a major clinical challenge. Various polysaccharides have been used to control biofilm formation by drug-resistant fungi, and this study was undertaken to develop chitosan (CS)-modified materials and evaluate their abilities to inhibit Candida biofilm growth. CS was grafted with methacrylamide (MA) and acrylonitrile (AN) and, to improve its application characteristics further, was grafted with hyaluronic acid to produce CS-g-poly (MA-co-AN) HA complex. Grafting and complex formation were confirmed using spectroscopic techniques. CS-g-poly (MA-co-AN) HA was tested to investigate its ability to inhibit Candida albicans biofilm formation and showed significant antibiofilm activity at 200 µg/mL. Additionally, CS-g-poly (MA-co-AN) HA did not have any toxic effect on Caenorhabditis elegans. Thus, this study provides an innovative means of preventing microorganism-associated biofilm formation.}, } @article {pmid35884186, year = {2022}, author = {Dutt, Y and Dhiman, R and Singh, T and Vibhuti, A and Gupta, A and Pandey, RP and Raj, VS and Chang, CM and Priyadarshini, A}, title = {The Association between Biofilm Formation and Antimicrobial Resistance with Possible Ingenious Bio-Remedial Approaches.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884186}, issn = {2079-6382}, support = {UZRPD1L0011//VtR Inc-CGU, R.O.C./ ; SCRPD1L0221//Chang Gung University/ ; }, abstract = {Biofilm has garnered a lot of interest due to concerns in various sectors such as public health, medicine, and the pharmaceutical industry. Biofilm-producing bacteria show a remarkable drug resistance capability, leading to an increase in morbidity and mortality. This results in enormous economic pressure on the healthcare sector. The development of biofilms is a complex phenomenon governed by multiple factors. Several attempts have been made to unravel the events of biofilm formation; and, such efforts have provided insights into the mechanisms to target for the therapy. Owing to the fact that the biofilm-state makes the bacterial pathogens significantly resistant to antibiotics, targeting pathogens within biofilm is indeed a lucrative prospect. The available drugs can be repurposed to eradicate the pathogen, and as a result, ease the antimicrobial treatment burden. Biofilm formers and their infections have also been found in plants, livestock, and humans. The advent of novel strategies such as bioinformatics tools in treating, as well as preventing, biofilm formation has gained a great deal of attention. Development of newfangled anti-biofilm agents, such as silver nanoparticles, may be accomplished through omics approaches such as transcriptomics, metabolomics, and proteomics. Nanoparticles' anti-biofilm properties could help to reduce antimicrobial resistance (AMR). This approach may also be integrated for a better understanding of biofilm biology, guided by mechanistic understanding, virtual screening, and machine learning in silico techniques for discovering small molecules in order to inhibit key biofilm regulators. This stimulated research is a rapidly growing field for applicable control measures to prevent biofilm formation. Therefore, the current article discusses the current understanding of biofilm formation, antibiotic resistance mechanisms in bacterial biofilm, and the novel therapeutic strategies to combat biofilm-mediated infections.}, } @article {pmid35884185, year = {2022}, author = {Spiegel, C and Steixner, SJM and Coraça-Huber, DC}, title = {Antibiofilm Activity of Omega-3 Fatty Acids and Its Influence on the Expression of Biofilm Formation Genes on Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884185}, issn = {2079-6382}, abstract = {Background: Currently, 1-2% of all prosthetic joint surgeries are followed by an infection. These infections cause approximately 4% of deaths in the first year after surgery, while the 5-year mortality rate is up to 21%. Prosthetic joint infections are mainly caused by Staphylococcus aureus or Staphylococcus epidermis strains. Both species share the capability of biofilm formation and methicillin resistance. The formation of biofilm helps bacterial cells to withstand critical environmental conditions. Due to their tolerance against antibacterial substances, biofilms are a significant problem in modern medicine. Alternatives for the use of methicillin as a therapeutic are not yet widespread. The use of omega-3 fatty acids, such as docosahexaenoic acid, may help against prosthetic joint infections and lower mortality rates. The aim of this study is to evaluate if docosahexaenoic acid offers a safe anti-biofilm activity against Staphylococcus aureus and MRSA without enhancing icaADBC-dependent biofilm formation or additional stress responses, therefore enhancing antibiotic tolerance and resistance. Methods: In this study, we examined the gene expression of biofilm-associated genes and regulators. We performed RT-qPCR after RNA extraction of Staphylococcus aureus ATCC 29213 and one clinical MRSA strain. We compared gene expression of icaADBC, SarA, SigB, and agrAC under the influence of 1.25 mg /L and 0.625 mg/L of docosahexaenoic acid to their controls. Results: We found a higher expression of regulatory genes such as SarA, SigB, agrA, and agrC at 1.25 mg/L of docosahexaenoic acid in ATCC 29213 and a lower increase in gene expression levels in clinical MRSA isolates. icaADBC was not affected in both strains at both concentration levels by docosahexaenoic acid. Conclusions: Docosahexaenoic acid does not enhance icaADBC-dependent biofilm formation while still reducing bacterial CFU in biofilms. Docosahexaenoic acid can be considered an option as a therapeutic substance against biofilm formation and may be a good alternative in reducing the risk of MRSA formation.}, } @article {pmid35884184, year = {2022}, author = {Gülmez, D and Brown, JL and Butcher, MC and Delaney, C and Kean, R and Ramage, G and Short, B}, title = {Investigating Dual-Species Candida auris and Staphylococcal Biofilm Antiseptic Challenge.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884184}, issn = {2079-6382}, support = {TUI-2019-18176//Hacettepe University Scientific Research Projects Coordination Unit/ ; BB/V509541/1//GlaxoSmithKline (UK)/ ; }, abstract = {Candida auris can persistently colonize human skin, alongside a diverse bacterial microbiome. In this study we aimed to investigate the efficacy of antiseptic activities on dual-species interkingdom biofilms containing staphylococci to determine if antiseptic tolerance was negatively impacted by dual-species biofilms. Chlorhexidine, povidone iodine, and hydrogen peroxide (H2O2), were able to significantly reduce biofilm viable cell counts following exposure at 2%, 10%, and 3%, respectively. Notably, H2O2-treated biofilms were able to significantly recover and considerably repopulate following treatment. Fortunately, inter-kingdom interactions in dual-species biofilms of C. auris and staphylococci did not increase the tolerance of C. auris against antiseptics in vitro. These data indicate mixed infections are manageable with chlorhexidine and povidone iodine, but caution should be exercised in the consideration of H2O2.}, } @article {pmid35884162, year = {2022}, author = {Azevedo, AS and Melo, LDR}, title = {New Insights on Biofilm Antimicrobial Strategies, 2nd Volume.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884162}, issn = {2079-6382}, abstract = {In biofilms, microorganisms are able to communicate together and assemble by themselves, creating a consortium with different properties from the original free-floating microorganisms [...].}, } @article {pmid35884135, year = {2022}, author = {Hernández, P and Sánchez, MC and Llama-Palacios, A and Ciudad, MJ and Collado, L}, title = {Strategies to Combat Caries by Maintaining the Integrity of Biofilm and Homeostasis during the Rapid Phase of Supragingival Plaque Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884135}, issn = {2079-6382}, abstract = {Bacteria in the oral cavity, including commensals and opportunistic pathogens, are organized into highly specialized sessile communities, coexisting in homeostasis with the host under healthy conditions. A dysbiotic environment during biofilm evolution, however, allows opportunistic pathogens to become the dominant species at caries-affected sites at the expense of health-associated taxa. Combining tooth brushing with dentifrices or rinses combat the onset of caries by partially removes plaque, but resulting in the biofilm remaining in an immature state with undesirables' consequences on homeostasis and oral ecosystem. This leads to the need for therapeutic pathways that focus on preserving balance in the oral microbiota and applying strategies to combat caries by maintaining biofilm integrity and homeostasis during the rapid phase of supragingival plaque formation. Adhesion, nutrition, and communication are fundamental in this phase in which the bacteria that have survived these adverse conditions rebuild and reorganize the biofilm, and are considered targets for designing preventive strategies to guide the biofilm towards a composition compatible with health. The present review summarizes the most important advances and future prospects for therapies based on the maintenance of biofilm integrity and homeostasis as a preventive measure of dysbiosis focused on these three key factors during the rapid phase of plaque formation.}, } @article {pmid35884124, year = {2022}, author = {Abdelaziz, NA and Elkhatib, WF and Sherif, MM and Abourehab, MAS and Al-Rashood, ST and Eldehna, WM and Mostafa, NM and Elleboudy, NS}, title = {In Silico Docking, Resistance Modulation and Biofilm Gene Expression in Multidrug-Resistant Acinetobacter baumannii via Cinnamic and Gallic Acids.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884124}, issn = {2079-6382}, support = {Researchers Supporting Project number (RSP-2021/103); Grant Code: (22UQU4290565DSR08)‎//King Saud University, Riyadh, Saudi ‎Arabia; Deanship of Scientific Research at Umm Al-Qura University ‎/ ; }, abstract = {Despite the mounting global burden of antimicrobial resistance (AMR), the generation of new classes of effective antimicrobials still lags far behind. The interplay between multidrug resistance and biofilm formation in Acinetobacter baumannii has drastically narrowed the available therapeutic choices. The use of natural compounds holds promise as an alternate option for restoring the activity of existing antibiotics and attenuating virulence traits through reduced biofilm formation. This study aimed to evaluate the modulatory effect of combining cinnamic and gallic acids at ½MIC with various antibiotics against multidrug-resistant (MDR) A. baumannii clinical isolates as well as study the effect on the expression of the biofilm-associated genes (bap, csuE, ompA) via quantitative, real-time PCR. Combining cinnamic or gallic acid with imipenem, amikacin or doxycycline resulted in significant reduction of resistance (p < 0.05). On the contrary, no effect was recorded when both acids were combined with levofloxacin, and only cinnamic acid had a synergistic effect with colistin. The transcriptomic changes of biofilm-related genes in the presence of gallic acid at ½MIC were compared with untreated control samples. The fold expression values proved that gallic acid substantially down-regulated the respective genes in all five strong biofilm formers. Molecular docking studies of gallic and cinnamic acids on target genes revealed good binding affinities and verified the proposed mechanism of action. To the best of our knowledge, this is the first report on the effect of gallic acid on the expression of bap, csuE and ompA genes in A. baumannii, which may permit its use as an adjunct anti-virulence therapeutic strategy.}, } @article {pmid35884115, year = {2022}, author = {Altayb, HN and Elbadawi, HS and Baothman, O and Kazmi, I and Alzahrani, FA and Nadeem, MS and Hosawi, S and Chaieb, K}, title = {Whole-Genome Sequence of Multidrug-Resistant Methicillin-Resistant Staphylococcusepidermidis Carrying Biofilm-Associated Genes and a Unique Composite of SCCmec.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884115}, issn = {2079-6382}, support = {IFPRC-072-130-2020//King Abdulaziz University/ ; }, abstract = {Staphylococcus epidermidis is part of the normal human flora that has recently become an important opportunistic pathogen causing nosocomial infections and tends to be multidrug-resistant. In this investigation, we aimed to study the genomic characteristics of methicillin-resistant S. epidermidis isolated from clinical specimens. Three isolates were identified using biochemical tests and evaluated for drug susceptibility. Genomic DNA sequences were obtained using Illumina, and were processed for analysis using various bioinformatics tools. The isolates showed multidrug resistance to most of the antibiotics tested in this study, and were identified with three types (III(3A), IV(2B&5), and VI(4B)) of the mobile genetic element SCCmec that carries the methicillin resistance gene (mecA) and its regulators (mecI and mecR1). A total of 11 antimicrobial resistance genes (ARGs) was identified as chromosomally mediated or in plasmids; these genes encode for proteins causing decreased susceptibility to methicillin (mecA), penicillin (blaZ), fusidic acid (fusB), fosfomycin (fosB), tetracycline (tet(K)), aminoglycosides (aadD, aac(6')-aph(2'')), fluoroquinolone (MFS antibiotic efflux pump), trimethoprim (dfrG), macrolide (msr(A)), and chlorhexidine (qacA)). Additionally, the 9SE strain belongs to the globally disseminated ST2, and harbors biofilm-formation genes (icaA, icaB, icaC, icaD, and IS256) with phenotypic biofilm production capability. It also harbors the fusidic acid resistance gene (fusB), which could increase the risk of device-associated healthcare infections, and 9SE has been identified as having a unique extra SCC gene (ccrB4); this new composite element of the ccr type needs more focus to better understand its role in the drug resistance mechanism.}, } @article {pmid35884108, year = {2022}, author = {Ramić, D and Ogrizek, J and Bucar, F and Jeršek, B and Jeršek, M and Možina, SS}, title = {Campylobacter jejuni Biofilm Control with Lavandin Essential Oils and By-Products.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35884108}, issn = {2079-6382}, support = {51861//Slovenian Research Agency/ ; J4-2542//Slovenian Research Agency/ ; }, abstract = {The food industry is constantly struggling with one of the most prevalent biofilm-forming and food-borne pathogenic bacteria, Campylobacter jejuni. Different approaches are used to control biofilms in the food production chain, but none is fully effective. In this study, we aim to produce and determine the chemical profile of essential oils (EOs), ethanolic extracts of flowers prior to distillation (EFs), and ethanolic extracts of post-distillation waste material (EWMs) from Lavandula × intermedia 'Bila', 'Budrovka' St Nicholas and 'Budrovka', which were further used to reduce C. jejuni intercellular signaling, adhesion, and biofilm formation, as well as to test their antioxidant activity. Glycosides of hydroxycinnamic acids were the major constituents of both types of lavandin ethanolic extract, while linalool, linalyl acetate, 1,8-cineol, and camphor were the major compounds found in lavandin EOs. Tested EOs showed the best antibacterial activity with a minimal inhibitory concentration of 0.25 mg/mL. Lavandin EFs proved more effective in reducing C. jejuni intercellular signaling and adhesion compared to lavandin EOs and EWMs, while lavandin EOs showed a slightly better effect against biofilm formation. Interestingly, the best antioxidant activity was determined for lavandin EWMs. A positive and moderate correlation was found between the reduction of C. jejuni intercellular signaling and adhesion, as well as between adhesion and biofilm formation. These findings mean novel bacterial targets are of interest for biofilm control with alternative natural agents throughout the whole food production chain.}, } @article {pmid35881255, year = {2022}, author = {Sun, F and Sun, Y and Wang, Y and Yuan, Q and Xiong, L and Feng, W and Xia, P}, title = {Role of Penicillin-Binding Protein 1b in the Biofilm Inhibitory Efficacy of Ceftazidime Against Escherichia coli.}, journal = {Current microbiology}, volume = {79}, number = {9}, pages = {271}, pmid = {35881255}, issn = {1432-0991}, support = {81373451//National Natural Science Foundation of China/ ; 4139Z239B//Chongqing Innovation Leading Talent Project/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Ceftazidime/pharmacology ; Escherichia coli ; *Escherichia coli Infections/microbiology ; *Escherichia coli Proteins/genetics/metabolism ; Humans ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins/genetics ; }, abstract = {Penicillin-binding proteins (PBPs) play an important role in bacterial biofilm formation and are the targets of β-lactam antibiotics. This study aimed to investigate the effect of the β-lactam antibiotic ceftazidime (CAZ) at subminimal inhibitory concentration (sub-MIC) on the biofilm formation of Escherichia coli by targeting PBPs. In this study, PBP1a (encoded by mrcA), PBP1b (encoded by mrcB) and PBP3 (encoded by ftsI), which have high affinity for CAZ, were deleted from the E. coli strain. The mrcB mutant showed lower adhesion, biofilm formation and swimming motility, whereas the knockout of mrcA or ftsI had no obvious influence on the biofilm-associated indicators mentioned above. After treatment with sub-MIC of CAZ, the adhesion, biofilm formation and swimming motility of the mrcB-mutant strain were not different or were slightly reduced compared with those of the untreated group. However, sub-MIC of CAZ still significantly inhibited these biofilm-associated indicators in mrcA- and ftsI-mutant strains. In addition, consistent with the bacterial motility results, the deletion of the mrcB gene reduced the flagellar numbers and the expression of flagellar structural genes, but flagellum-related indicators in the mrcB-mutant strain treated with CAZ were similar to those in the untreated group. Bioinformatic analysis showed that CAZ binds to Lys287, Lys274, Glu281, and Arg286 in PBP1b. Taken together, these results suggest that CAZ reduced flagellar synthesis and bacterial motility by binding with PBP1b and thereby inhibited the adhesion and biofilm formation of E. coli.}, } @article {pmid35880891, year = {2022}, author = {Zhang, Z and Yang, Y and Sun, Q and Zeng, W and Li, Y}, title = {Inhibition of Biofilm Formation and Virulence Factors of Cariogenic Oral Pathogen Streptococcus mutans by Shikimic Acid.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0119922}, pmid = {35880891}, issn = {2165-0497}, mesh = {Animals ; Biofilms ; *Biological Products ; Cattle ; *Dental Caries ; Humans ; Plant Extracts/pharmacology ; Shikimic Acid/pharmacology ; Streptococcus mutans/physiology ; Virulence Factors ; }, abstract = {Streptococcus mutans is known as an important oral pathogen causing dental caries, a widespread oral infectious disease. S. mutans synthesize exopolysaccharide (EPS) using glucosyltransferases (Gtfs), resulting in biofilm formation on the tooth surface. Bacterial cells in the biofilms become strongly resistant to a harsh environment, such as antibiotics and host defense mechanisms, making biofilm-based infections difficult to eliminate. Discovering novel antibiofilm agents, especially from natural products, helps to develop effective strategies against this kind of diseases. The present study investigated the inhibitory effect of shikimic acid (SA), one abundant compound derived from Illicium verum extract, on the biofilm formation of S. mutans. We found SA can reduce the EPS synthesized by this oral pathogen and modulate the transcription of biofilm formation related genes, leading to fewer bacterial cells in its biofilm. SA also interacted with cell membrane and membrane proteins, causing damage to bacterial cells. Ex vivo testing of biofilm formation on bovine teeth showed SA strongly decreased the number of S. mutans cells and the number of EPS accumulated on dental enamel surfaces. Moreover, SA exhibits almost no toxicity to human oral cells evaluated by in vitro biocompatibility assay. In conclusion, shikimic acid exhibits remarkable antibiofilm activity against S. mutans and has the potential to be further developed as a novel anticaries agent. IMPORTANCE Natural products are an important and cost-effective source for screening antimicrobial agents. Here, we identified one compound, shikimic acid, from Illicium verum extract, exhibiting antimicrobial activity against S. mutans proliferation. It also inhibits biofilm formation of this bacteria through decreasing Gtf expression and EPS synthesis. Furthermore, this compound exhibits no significant cytotoxicity at its MIC against S. mutans, providing evidence for its clinical application.}, } @article {pmid35880077, year = {2022}, author = {Benyoussef, W and Deforet, M and Monmeyran, A and Henry, N}, title = {Flagellar Motility During E. coli Biofilm Formation Provides a Competitive Disadvantage Which Recedes in the Presence of Co-Colonizers.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {896898}, pmid = {35880077}, issn = {2235-2988}, mesh = {*Biofilms ; *Escherichia coli/metabolism ; Flagella ; }, abstract = {In nature, bacteria form biofilms in very diverse environments, involving a range of specific properties and exhibiting competitive advantages for surface colonization. However, the underlying mechanisms are difficult to decipher. In particular, the contribution of cell flagellar motility to biofilm formation remains unclear. Here, we examined the ability of motile and nonmotile E. coli cells to form a biofilm in a well-controlled geometry, both in a simple situation involving a single-species biofilm and in the presence of co-colonizers. Using a millifluidic channel, we determined that motile cells have a clear disadvantage in forming a biofilm, exhibiting a long delay as compared to nonmotile cells. By monitoring biofilm development in real time, we observed that the decisive impact of flagellar motility on biofilm formation consists in the alteration of surface access time potentially highly dependent on the geometry of the environment to be colonized. We also report that the difference between motile and nonmotile cells in the ability to form a biofilm diminishes in the presence of co-colonizers, which could be due to motility inhibition through the consumption of key resources by the co-colonizers. We conclude that the impact of flagellar motility on surface colonization closely depends on the environment properties and the population features, suggesting a unifying vision of the role of cell motility in surface colonization and biofilm formation.}, } @article {pmid35878769, year = {2022}, author = {Chen, L and Wang, XD and Chang, JS and Lee, DJ}, title = {Biofilm with highly heterogeneous interior structure for pollutant removal: Effects of individual extracellular polymeric substance.}, journal = {Bioresource technology}, volume = {361}, number = {}, pages = {127669}, doi = {10.1016/j.biortech.2022.127669}, pmid = {35878769}, issn = {1873-2976}, mesh = {Biofilms ; *Environmental Pollutants ; *Extracellular Polymeric Substance Matrix ; Polysaccharides/chemistry ; }, abstract = {For the first time, this study reveals the effects of an individual component of extracellular polymeric substances on the substrate consumption rates by the embedded cells based on the highly heterogeneous interior structures of a working biofilm. The flow-across mode in operation established a boundary-layer flow field with high transport resistance, making the uniformly structured model valid. Conversely, the flow field of the flow-through mode is determined by 46% jointly by proteins and β-d-glucopyranose polysaccharides. The substrate consumption rates hindered by β-d-glucopyranose polysaccharide is up to 60% over the 20%-40% biofilm height from the bottom, much lower than expected by the uniformly structured models. The strategies to maximize the biofilm performance have been suggested.}, } @article {pmid35876630, year = {2022}, author = {Hsu, CC and Hsu, RB and Oon, XH and Chen, YT and Chen, JW and Hsu, CH and Kuo, YM and Shih, YH and Chia, JS and Jung, CJ}, title = {Streptococcus mutans PrsA mediates AtlA secretion contributing to extracellular DNA release and biofilm formation in the pathogenesis of infective endocarditis.}, journal = {Virulence}, volume = {13}, number = {1}, pages = {1379-1392}, pmid = {35876630}, issn = {2150-5608}, mesh = {Bacterial Proteins/metabolism ; Biofilms ; DNA/metabolism ; *Endocarditis ; *Endocarditis, Bacterial ; Humans ; Streptococcus mutans/genetics ; }, abstract = {The role of secretion chaperone-regulated virulence proteins in the pathogenesis of infective endocarditis (IE) induced by viridans streptococci such as Streptococcus mutans is unclear. In this study, we investigated the contribution of the foldase protein PrsA, a putative parvulin-type peptidyl-prolyl isomerase, to the pathogenesis of S. mutans-induced IE. We found that a prsA-deficient strain had reduced virulence in terms of formation of vegetation on damaged heart valves, as well as reduced autolysis activity, eDNA release and biofilm formation capacity. The secretion and surface exposure of AtlA in vitro was reduced in the prsA-deficient mutant strain, and complementation of recombinant AtlA in the culture medium restored a wild type biofilm phenotype of the prsA-deficient mutant strain. This result suggests that secretion and surface localization of AtlA is regulated by PrsA during biofilm formation. Together, these results demonstrate that S. mutans PrsA could regulate AtlA-mediated eDNA release to contribute to biofilm formation in the pathogenesis of IE.}, } @article {pmid35876589, year = {2022}, author = {Macias-Valcayo, A and Aguilera-Correa, JJ and Broncano, A and Parron, R and Auñon, A and Garcia-Cañete, J and Blanco, A and Esteban, J}, title = {Comparative In Vitro Study of Biofilm Formation and Antimicrobial Susceptibility in Gram-Negative Bacilli Isolated from Prosthetic Joint Infections.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0085122}, pmid = {35876589}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Biofilms ; Escherichia coli ; *Gram-Negative Bacteria ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Prosthetic joint infections (PJIs) are typically caused by microorganisms that grow in biofilms. Traditional antimicrobial susceptibility tests are based on the study of planktonic bacteria that might lead to missing the biofilm behavior and to a treatment failure. This study was designed to analyze the antimicrobial susceptibility of clinical Gram-negative bacilli (GNB) isolates from PJIs in planktonic and sessile states and the possible relationship between antimicrobial resistance and biofilm formation. A total of 46 clinical isolates from patients with PJIs (mainly hip and knee prostheses) plus three GNB ATCC isolates were studied. The Minimal Inhibitory Concentration (MIC), minimal bactericidal concentration (MBC), minimal biofilm inhibitory concentration (MBIC), and minimal biofilm eradication concentration (MBEC) were assessed using a previously published methodology. Almost all of the GNB clinical isolates tested were biofilm forming. Pseudomonas aeruginosa was the largest biofilm-forming species. A comparison of MBIC90 versus MIC90 shows an increase higher than 1- to -2-fold dilutions in most antimicrobials studied, and MBEC90 was significantly higher than MIC90, becoming resistant to all the antimicrobial drugs tested. Higher biofilm production values were obtained in antibiotic-susceptible Escherichia coli in comparison to their resistant counterparts. However, regarding the relationships between antimicrobial resistance and biofilm formation, our analysis showed that each strain differed. A high antimicrobial resistance rate was found among the GNB studied. Moreover, almost all bacterial isolates were in vitro biofilm formers. Although there was no significant association between biofilm and antibiotic resistance, multidrug-resistant isolates were found to be greater biofilm formers than non-multidrug-resistant isolates. IMPORTANCE This study is the first one to analyze a high number of isolates of Gram-negative bacilli that are the cause of prosthetic joint infection. The analysis includes biofilm development and antimicrobial susceptibility testing of both planktonic and sessile bacteria. The obtained results support the clinical knowledge about the treatment of these bacteria when biofilms are involved.}, } @article {pmid35875570, year = {2022}, author = {Tarsitano, J and Ramis, LY and Alonso, LG and Russo, DM and Zorreguieta, A}, title = {RapD Is a Multimeric Calcium-Binding Protein That Interacts With the Rhizobium leguminosarum Biofilm Exopolysaccharide, Influencing the Polymer Lengths.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {895526}, pmid = {35875570}, issn = {1664-302X}, abstract = {Rhizobium leguminosarum synthesizes an acidic polysaccharide mostly secreted to the extracellular medium, known as exopolysaccharide (EPS) and partially retained on the bacterial surface as a capsular polysaccharide (CPS). Rap proteins, extracellular protein substrates of the PrsDE type I secretion system (TISS), share at least one Ra/CHDL (cadherin-like) domain and are involved in biofilm matrix development either through cleaving the polysaccharide by Ply glycanases or by altering the bacterial adhesive properties. It was shown that the absence or excess of extracellular RapA2 (a monomeric CPS calcium-binding lectin) alters the biofilm matrix's properties. Here, we show evidence of the role of a new Rap protein, RapD, which comprises an N-terminal Ra/CHDL domain and a C-terminal region of unknown function. RapD was completely released to the extracellular medium and co-secreted with the other Rap proteins in a PrsDE-dependent manner. Furthermore, high levels of RapD secretion were found in biofilms under conditions that favor EPS production. Interestingly, size exclusion chromatography of the EPS produced by the ΔrapA2ΔrapD double mutant showed a profile of EPS molecules of smaller sizes than those of the single mutants and the wild type strain, suggesting that both RapA2 and RapD proteins influence EPS processing on the cell surface. Biophysical studies showed that calcium triggers proper folding and multimerization of recombinant RapD. Besides, further conformational changes were observed in the presence of EPS. Enzyme-Linked ImmunoSorbent Assay (ELISA) and Binding Inhibition Assays (BIA) indicated that RapD specifically binds the EPS and that galactose residues would be involved in this interaction. Taken together, these observations indicate that RapD is a biofilm matrix-associated multimeric protein that influences the properties of the EPS, the main structural component of the rhizobial biofilm.}, } @article {pmid35875177, year = {2022}, author = {Aoki, M and Miyashita, Y and Miwa, T and Watari, T and Yamaguchi, T and Syutsubo, K and Hayashi, K}, title = {Manganese oxidation and prokaryotic community analysis in a polycaprolactone-packed aerated biofilm reactor operated under seawater conditions.}, journal = {3 Biotech}, volume = {12}, number = {9}, pages = {187}, pmid = {35875177}, issn = {2190-572X}, abstract = {Biogenic manganese oxides (BioMnOx) have been receiving increasing attention for the removal of environmental contaminants and recovery of minor metals from water environments. However, the enrichment of heterotrophic Mn(II)-oxidizing microorganisms for BioMnOx production in the presence of fast-growing coexisting heterotrophs is challenging. In our previous work, we revealed that polycaprolactone (PCL), a biodegradable aliphatic polyester, can serve as an effective solid organic substrate to enrich Mn-oxidizing microbial communities under seawater conditions. However, marine BioMnOx-producing bioreactor systems utilizing PCL have not yet been established. Therefore, a laboratory-scale continuous-flow PCL-packed aerated biofilm (PAB) reactor was operated for 238 days to evaluate its feasibility for BioMnOx production under seawater conditions. After the start-up of the reactor, the average dissolved Mn removal rates of 0.4-2.3 mg/L/day, likely caused by Mn(II) oxidation, were confirmed under different influent dissolved Mn concentrations (2.5-14.0 mg/L on average) and theoretical hydraulic retention time (0.19-0.77 day) conditions. The 16S rRNA gene amplicon sequencing analysis suggested the presence of putative Mn(II)-oxidizing and PCL-degrading bacterial lineages in the reactor. Two highly dominant operational units (OTUs) in the packed PCL-associated biofilm were assigned to the genera Marinobacter and Pseudohoeflea, whereas the genus Lewinella and unclassified Alphaproteobacteria OTUs were highly dominant in the MnOx-containing black/dark brown precipitate-associated biofilm formed in the reactor. Excitation-emission matrix fluorescence spectroscopy analysis revealed the production of tyrosine- and tryptophane-like components, which may serve as soluble heterotrophic organic substrates in the reactor. Our findings indicate that PAB reactors are potentially applicable to BioMnOx production under seawater conditions.}, } @article {pmid35873056, year = {2022}, author = {Wu, Y and Liu, X and Wang, Q and Han, D and Lin, S}, title = {Fe3O4-Fused Magnetic Air Stone Prepared From Wasted Iron Slag Enhances Denitrification in a Biofilm Reactor by Increasing Electron Transfer Flow.}, journal = {Frontiers in chemistry}, volume = {10}, number = {}, pages = {948453}, pmid = {35873056}, issn = {2296-2646}, abstract = {nFe3O4 was prepared from waste iron slag and loaded onto air stone (named magnetic air stone or MAS in the following text). The main component of air stone is carborundum. To study the magnetic effects of MAS on denitrification, a biofilm reactor was built, and its microbial community structure and electron transfer in denitrification were analyzed. The results showed that MAS improved the performance of the reactor in both carbon and nitrogen removal compared with air stone (AS) control, and the average removal efficiencies of COD, TN, and NH4 [+]-N increased by 17.15, 16.1, and 11.58%, respectively. High-throughput sequencing revealed that magnetism of MAS had a significant effect on the diversity and richness of microorganisms in the biofilm. The MAS also reduced the inhibition of rotenone, mipalene dihydrochloride (QDH), and sodium azide on the respiratory chain in denitrification and enhanced the accumulation of nitrite, in order to provide sufficient substrate for the following denitrification process. Therefore, the denitrification process is accelerated by the MAS. The results allowed us to deduce the acceleration sites of MAS in the denitrification electron transport chain. The existence of MAS provides a new rapid method for the denitrifying electron transport process. Even in the presence of respiratory inhibitors of denitrifying enzymes, the electron transfer acceleration provided by MAS still exists objectively. This is the mechanism through which MAS can restore the denitrification process inhibited by respiratory inhibitors to a certain extent.}, } @article {pmid35869980, year = {2022}, author = {Higa, B and Cintra, BS and Álvarez, CM and Ribeiro, AB and Ferreira, JC and Tavares, DC and Enriquez, V and Martinez, LR and Pires, RH}, title = {Ozonated oil is effective at killing Candida species and Streptococcus mutans biofilm-derived cells under aerobic and microaerobic conditions.}, journal = {Medical mycology}, volume = {60}, number = {8}, pages = {}, pmid = {35869980}, issn = {1460-2709}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; R90 DE022530/DE/NIDCR NIH HHS/United States ; 2019/26418-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; R01AI145559//National Institute of Allergy and Infectious Diseases/ ; R01 AI145559/AI/NIAID NIH HHS/United States ; T90DE021990/NH/NIH HHS/United States ; }, mesh = {Animals ; Biofilms ; *Candida ; Candida albicans ; Mice ; *Streptococcus mutans ; Sunflower Oil ; }, abstract = {UNLABELLED: This study explores the growth of bacterial, fungal, and interkingdom biofilms under aerobiosis or microaerobic conditions and the effect of ozonated sunflower oil on these biofilms. Candida species and Streptococcus mutans were used to study this interaction due to their importance in oral health and disease as these microorganisms display a synergistic relationship that manifests in the onset of caries and tooth decay. Biofilms were developed in a 96-well microtiter plate at 37ºC for 24 h, under aerobiosis or microaerobic conditions, and treated with ozonated oil for 5 to 120 min. All the microorganisms formed biofilms in both oxygenation conditions. Scanning electron microscopy was used to visualize biofilm morphology. Rodent experiments were performed to verify the oil-related toxicity and its efficacy in oral candidiasis. The growth of all Candida species was increased when co-cultured with S. mutans, whilst the growth of bacterium was greater only when co-cultured with C. krusei and C. orthopsilosis under aerobiosis and microaerobic conditions, respectively. Regardless of the oxygenation condition, ozonated oil significantly reduced the viability of all the tested biofilms and infected mice, showing remarkable microbicidal activity as corroborated with confocal microscopy and minimal toxicity. Thus, ozonated oil therapy can be explored as a strategy to control diseases associated with these biofilms especially in the oral cavity.

LAY SUMMARY: We demonstrated that ozonated sunflower oil is effective at killing the biofilms formed by Candida species, by the bacterium Streptococcus mutans, or by both micoorganisms that can interact in the oral cavity, making it a potential therapeutic option for the treatment of these infections.}, } @article {pmid35869808, year = {2022}, author = {Yan, D and Tajima, H and Cline, LC and Fong, RY and Ottaviani, JI and Shapiro, HY and Blumwald, E}, title = {Genetic modification of flavone biosynthesis in rice enhances biofilm formation of soil diazotrophic bacteria and biological nitrogen fixation.}, journal = {Plant biotechnology journal}, volume = {20}, number = {11}, pages = {2135-2148}, pmid = {35869808}, issn = {1467-7652}, mesh = {*Nitrogen Fixation/genetics ; *Oryza/metabolism ; Soil ; Gene Editing ; Apigenin/metabolism ; Fertilizers ; Crops, Agricultural ; Bacteria/genetics ; Nitrogen/metabolism ; Edible Grain/metabolism ; Biofilms ; }, abstract = {Improving biological nitrogen fixation (BNF) in cereal crops is a long-sought objective; however, no successful modification of cereal crops showing increased BNF has been reported. Here, we described a novel approach in which rice plants were modified to increase the production of compounds that stimulated biofilm formation in soil diazotrophic bacteria, promoted bacterial colonization of plant tissues and improved BNF with increased grain yield at limiting soil nitrogen contents. We first used a chemical screening to identify plant-produced compounds that induced biofilm formation in nitrogen-fixing bacteria and demonstrated that apigenin and other flavones induced BNF. We then used CRISPR-based gene editing targeting apigenin breakdown in rice, increasing plant apigenin contents and apigenin root exudation. When grown at limiting soil nitrogen conditions, modified rice plants displayed increased grain yield. Biofilm production also modified the root microbiome structure, favouring the enrichment of diazotrophic bacteria recruitment. Our results support the manipulation of the flavone biosynthetic pathway as a feasible strategy for the induction of biological nitrogen fixation in cereals and a reduction in the use of inorganic nitrogen fertilizers.}, } @article {pmid35869653, year = {2022}, author = {Behera, SK and Panda, AK and Mishra, R and Mahanty, A and Bisht, SS}, title = {Structure based virtual screening and molecular dynamics of natural anti-biofilm compounds against SagS response regulator/sensor kinase in Pseudomonas aeruginosa.}, journal = {Journal of biomolecular structure & dynamics}, volume = {}, number = {}, pages = {1-16}, doi = {10.1080/07391102.2022.2100482}, pmid = {35869653}, issn = {1538-0254}, abstract = {SagS sensor regulator plays a vital role in biofilm development of Pseudomonas aeruginosa which subsequently makes the cells more tolerant to various antimicrobials. The multidrug resistance (MDR) issue has risen substantially in recent years and is considered a global threat. Therefore, alternative compounds should be unearthed immediately to address the issues related to P. aeruginosa drug resistance for which SagS could be a candidate. The present study is an attempt to screen natural anti-biofilm compounds as the potent inhibitors of SagS. Twenty natural anti-biofilm/quorum sensing inhibiting compounds were retrieved from various literatures with significant inhibitory effects against P. aeruginosa biofilm from in-vitro experiments which were screened using various pharmacokinetic parameters. The screened and three standard drugs were docked against SagS-HisKA using AutoDock 4.2 tool, which were further analysed by MD simulations to understand the binding mode of compounds and dynamic behaviour of the complexes. Two potential anti-biofilm natural compounds, pinocembrin with binding affinity (-7.19 kcal/mol), vestitol (-7.18 kcal/mol) and the standard drug ceftazidime (-8.89 kcal/mol) were selected based on filtered parameters and better binding affinity. The trajectory analysis of MD simulations reflected Pinocembrin in stabilizing the system compared to ceftazidime. The existing reports state that the natural products represent promising source of therapy with least or almost nil adverse effect compared to synthetic drugs which is well collated with our in-silico findings. This investigation can save both time and cost required for in-vitro and in-vivo analysis for designing of a novel anti-biofilm agent against P. aeruginosa biofilm-associated infections.Communicated by Ramaswamy H. Sarma.}, } @article {pmid35869264, year = {2022}, author = {Ranjbar, A and Rasooli, I and Jahangiri, A and Ramezanalizadeh, F}, title = {Specific egg yolk antibody raised to biofilm associated protein (Bap) is protective against murine pneumonia caused by Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {12576}, pmid = {35869264}, issn = {2045-2322}, mesh = {*Acinetobacter Infections/prevention & control ; *Acinetobacter baumannii ; Animals ; Antibodies/pharmacology ; Biofilms ; Chickens ; Egg Yolk ; Female ; Immunoglobulins ; Mice ; *Pneumonia/prevention & control ; }, abstract = {Acinetobacter baumannii easily turns into pan drug-resistant (PDR) with a high mortality rate. No effective commercial antibiotic or approved vaccine is available against drug-resistant strains of this pathogen. Egg yolk immunoglobulin (IgY) could be used as a simple and low-cost biotherapeutic against its infections. This study evaluates the prophylactic potential of IgY against A. baumannii in a murine pneumonia model. White Leghorn hens were immunized with intramuscular injection of the recombinant biofilm-associated protein (Bap) from A. baumannii on days 0, 21, 42, and 63. The reactivity and antibiofilm activity of specific IgYs raised against the Bap was evaluated by indirect ELISA and a microtiter plate assay for biofilm formation. The IgYs against Bap were able to decrease the biofilm formation ability of A. baumannii and protect the mice against the challenge of A. baumannii. IgYs antibody raised here shows a good antigen-specificity and protectivity which can be used in passive immunotherapy against A. baumannii. In conclusion, the IgY against biofilm-associated protein proves prophylactic in a murine pneumonia model.}, } @article {pmid35869109, year = {2022}, author = {Godzieba, M and Zubrowska-Sudol, M and Walczak, J and Ciesielski, S}, title = {Development of microbial communities in biofilm and activated sludge in a hybrid reactor.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {12558}, pmid = {35869109}, issn = {2045-2322}, mesh = {Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; *Microbiota/genetics ; RNA, Ribosomal, 16S/genetics ; *Sewage/microbiology ; Waste Disposal, Fluid ; Wastewater/microbiology ; }, abstract = {Microorganisms play a key role in biological wastewater treatment. The form in which biomass develops determines the efficiency and mechanisms of organic compound conversion, due to different conditions in various microbial structures. However, the results of studies comparing the microbial communities in biofilm and activated sludge have often conflicted. Therefore, this study compared the composition and development of the bacterial communities in biofilm and activated sludge in a hybrid reactor, employing 16S rRNA sequencing. Statistical analysis of the sequencing data included the identification of taxa characteristic to the biofilm and activated sludge, alpha and beta diversity analysis, and network analysis. These analyses indicated that the biofilm bacterial community was richer and more diverse than the activated sludge community. The mean numbers of OTU were 1614 in the biofilm and 993 in the activated sludge, and the mean values of the Chao1 (1735 vs. 1105) and Shannon (5.3 vs. 4.3) biodiversity indices were significantly higher for the biofilm. The biofilm was a better environment for development of nitrifiers (e.g., Nitrosomonas, Nitrospira) and phosphorus accumulating organisms (Candidatus Accumulibacter). Bacteria in the biofilm co-occurrence network had more connections (based on Spearman's rank correlation coefficient) with each other, indicating that they interact more than those in the activated sludge.}, } @article {pmid35868120, year = {2022}, author = {Wu, Y and Du, Q and Wan, Y and Zhao, Q and Li, N and Wang, X}, title = {Autotrophic nitrate reduction to ammonium via reverse electron transfer in Geobacter dominated biofilm.}, journal = {Biosensors & bioelectronics}, volume = {215}, number = {}, pages = {114578}, doi = {10.1016/j.bios.2022.114578}, pmid = {35868120}, issn = {1873-4235}, mesh = {*Ammonium Compounds ; Biofilms ; *Biosensing Techniques ; Electrons ; *Geobacter ; Nitrates ; Oxidation-Reduction ; }, abstract = {Geobacter dominated electroactive biofilms (EABs) have been demonstrated to perform bidirectional extracellular electron transfer (EET) in bioelectrochemical systems, but it is largely unknown when nitrate is the electron acceptor at the cathode. If reverse EET occurs on biocathode, this EAB has to perform dissimilatory nitrate reduction to ammonia (DNRA) rather than denitrification according to genomes. Here, we have proven the feasibility of reverse bioelectron transfer in EAB, achieving a DNRA efficiency up to 93 ± 3% and high Faraday efficiency of 74 ± 1%. Constant current was found to be more effective than constant potential to maintain Geobacter on the cathode, which highly determines this electrotrophic respiration. The prevalent DNRA at constant current surpassed denitrification, demonstrated by the reverse tendencies of DNRA (nrfA) and denitrification (nirS and nirK) gene transcription. Metatranscriptomics further revealed the possible electron uptake mechanisms by which the outer membrane (OmcZ and OmcB) and periplasmic cytochromes (PpcB and PpcD) may be involved. These findings extend our understanding of the bidirectional electron transfer and advance the applications of EABs.}, } @article {pmid35867872, year = {2022}, author = {Kashyap, S and Sidhu, H and Sharma, P and Capalash, N}, title = {3-indoleacetonitrile attenuates biofilm formation and enhances sensitivity to imipenem in Acinetobacter baumannii.}, journal = {Pathogens and disease}, volume = {80}, number = {1}, pages = {}, doi = {10.1093/femspd/ftac029}, pmid = {35867872}, issn = {2049-632X}, mesh = {Acetonitriles/*pharmacology ; *Acinetobacter Infections/drug therapy ; *Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/therapeutic use ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Carbapenems/metabolism/pharmacology/therapeutic use ; Humans ; Imipenem/pharmacology ; Microbial Sensitivity Tests ; beta-Lactamases/genetics/metabolism ; }, abstract = {Acinetobacter baumannii poses a global danger due to its ability to resist most of the currently available antimicrobial agents. Furthermore, the rise of carbapenem-resistant A. baumannii isolates has limited the treatment options available. In the present study, plant auxin 3-indoleacetonitrile (3IAN) was found to inhibit biofilm formation and motility of A. baumannii at sublethal concentration. Mechanistically, 3IAN inhibited the synthesis of the quorum sensing signal 3-OH-C12-HSL by downregulating the expression of the abaI autoinducer synthase gene. 3IAN was found to reduce the minimum inhibitory concentration of A. baumannii ATCC 17978 against imipenem, ofloxacin, ciprofloxacin, tobramycin, and levofloxacin, and significantly decreased persistence against imipenem. Inhibition of efflux pumps by downregulating genes expression may be responsible for enhanced sensitivity and low persistence. 3IAN reduced the resistance to imipenem in carbapenem-resistant A. baumannii isolates by downregulating the expression of OXA β-lactamases (blaoxa-51 and blaoxa-23), outer membrane protein carO, and transporter protein adeB. These findings demonstrate the therapeutic potential of 3IAN, which could be explored as an adjuvant with antibiotics for controlling A. baumannii infections.}, } @article {pmid35865928, year = {2022}, author = {Misra, T and Tare, M and Jha, PN}, title = {Insights Into the Dynamics and Composition of Biofilm Formed by Environmental Isolate of Enterobacter cloacae.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {877060}, pmid = {35865928}, issn = {1664-302X}, abstract = {Bacterial biofilms are clinically admissible and illustrate an influential role in infections, particularly those related to the implant of medical devices. The characterization of biofilms is important to understand the etiology of the diseases. Enterobacter cloacae are known for causing infections by forming biofilms on various abiotic surfaces, such as medical devices. However, a detailed characterization in terms of morphology and the molecular composition of the formed biofilms by this bacterium is sparse. The present study provides insights into the biofilm formation of E. cloacae SBP-8, an environmental isolate, on various surfaces. We performed assays to understand the biofilm-forming capability of the SBP-8 strain and characterized the adhering potential of the bacteria on the surface of different medical devices (foley latex catheter, enteral feeding tube, and glass) at different temperatures. We found that medical devices exhibited strong colonization by E. cloacae SBP-8. Using field emission-scanning electron microscopy (FE-SEM) studies, we characterized the biofilms as a function of time. It indicated stronger biofilm formation in terms of cellular density and EPS production on the surfaces. Further, we characterized the biofilm employing surface-enhanced Raman spectroscopy (SERS) and identified the vast heterogenic nature of the biofilm-forming molecules. Interestingly, we also found that this heterogeneity varies from the initial stages of biofilm formation until the maturation and dispersion. Our studies provide insights into biofilm composition over a period of time, which might aid in understanding the biofilm dispersion phases, to enhance the presently available treatment strategies.}, } @article {pmid35865585, year = {2022}, author = {M Fathil, MA and Faris Taufeq, FY and Suleman Ismail Abdalla, S and Katas, H}, title = {Roles of chitosan in synthesis, antibacterial and anti-biofilm properties of bionano silver and gold.}, journal = {RSC advances}, volume = {12}, number = {30}, pages = {19297-19312}, pmid = {35865585}, issn = {2046-2069}, abstract = {Antibiotic-resistance and bacterial bioburden on wound surfaces are the significant challenges to wound healing. Silver and gold nanoparticles (are termed as AgNPs and AuNPs) have been investigated as alternative antimicrobial agents to combat antibiotic-resistant bacterial infections owing to their antibacterial and anti-biofilm activities. Chitosan (CS) has largely been used in nanoparticle synthesis as a stabilizing or capping agent. In this study, AgNPs and AuNPs were synthesized using different concentrations of aqueous extract of tiger milk mushroom (Lignosus rhinocerotis) (WETMM) and CS as reducing and stabilizing agent, respectively. Particle size and morphology of both were determined by dynamic light scattering (DLS) method and transmission electron microscopic analysis (TEM). FTIR analysis was conducted to determine the interactions between nanoparticle precursors. The observed peaks at 450 nm and 534-565 nm using a spectrophotometer were corresponded to the surface Plasmon resonance of AgNPs and AuNPs respectively, indicating the formation of respective nanoparticles. FTIR analysis confirmed the role of WETMM as a reducing agent and CS as a stabilizer of AgNPs and AuNPs. Faster formation of nanoparticles was observed besides an increase in particle size when higher CS concentrations were used. TEM micrographs revealed the spherical shape of most nanoparticles with particle sizes in the range of 4 to 58 nm and 18 to 28 nm for AgNPs and AuNPs, respectively. Both nanoparticles exhibited antimicrobial activity against Gram-positive and -negative bacteria, with AgNPs showing a superior antibacterial efficacy than AuNPs. Both microbroth dilution and agar well diffusion assays indicated that CS was an important component to facilitate antibacterial activity for AuNPs. Contrarily, CS stabilization did not enhance the antibacterial efficacy of AgNPs. CS-stabilized AgNPs and AuNPs achieved biofilm inhibition of 53.21% and 79.39% for Pseudomonas aeruginosa and 48.71% and 48.16% for Staphylococcus aureus, respectively. Similarly, CS stabilization enhanced the anti-biofilm activity of AuNPs but no such effect was seen for AgNPs. In conclusion, CS-stabilized AgNPs and AuNPs possess both antimicrobial and anti-biofilm activities. However, CS acted differently when combined with AgNPs and AuNPs, needing further investigation and optimization to improve the antimicrobial activity of both nanoparticles.}, } @article {pmid35863019, year = {2022}, author = {Gu, M and Cheng, J and Lee, YG and Cho, JH and Suh, JW}, title = {Discovery of Novel Iminosugar Compounds Produced by Lactobacillus paragasseri MJM60645 and Their Anti-Biofilm Activity against Streptococcus mutans.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0112222}, pmid = {35863019}, issn = {2165-0497}, mesh = {Biofilms ; *Dental Caries ; Glycerol ; Humans ; Lactobacillus ; Streptococcus ; *Streptococcus mutans/physiology ; }, abstract = {The oral cavity contains a number of microbes. They interact with each other and play an important role in human health. Among oral cariogenic microbes, Streptococcus mutans is recognized a major etiological bacteria of dental caries. Lactobacilli strains have been promoted as possible probiotic agents against S. mutans. However, their inhibitory mechanism has not been well elucidated yet. In the present study, two new compounds with strong antibiofilm activities were purified from the culture supernatant of Lactobacillus paragasseri MJM60645, which was isolated from the human oral cavity. These compounds showed strong inhibitory activities against S. mutans biofilm formation, with IC50 (concentration at which 50% biofilm was inhibited) of 30.4 μM for compound 1 and 18.9 μM for compound 2. However, these compounds did not show bactericidal activities against S. mutans. Structure elucidation by nuclear magnetic resonance (NMR) and mass spectrometry showed that compound 1 was composed of two arabinofuranose iminosugars jointed with one glycerol and oleic acid, and compound 2 was composed of two arabinofuranose iminosugars jointed with one glycerol and nervonic acid. To the best of our knowledge, these structures were discovered for the first time in this study. Treatment of S. mutans with compound 1 strongly downregulated expression levels of genes related to biofilm formation, including gtfB, gtfC, gtfD, gbpB, brpA, spaP, ftf, and smu0630 without affecting the expression of comDE or relA. This study provides new insights into novel molecules produced by Lactobacillus to regulate the pathogenesis of S. mutans, facilitating a better understanding of the mechanism for interactions between Lactobacillus and S. mutans. IMPORTANCE In this study, we isolated lactic acid bacteria that inhibit streptococcal biofilm from the oral cavity of infants and identified two novel compounds from the supernatant of their culture broth. The two compounds are structurally similar, and both consist of iminosugars, glycerol, and unsaturated fatty acid. A search of the SciFinder database revealed that these structures are novel and were discovered for the first time in this study. Mechanism studies have shown that these compounds can inhibit the expression of biofilm synthesis-related genes. This is the first report that lactic acid bacteria inhibit streptococcal biofilms by small molecules with new chemical structures. This study not only expands the understanding of natural products derived from lactic acid bacteria but also provides a new paradigm for the understanding of the interaction of bacteria in the oral microbiota.}, } @article {pmid35862994, year = {2022}, author = {Lopes, ACUA and Lobo, CIV and Ribeiro, SM and Colin, JDS and Constantino, VCN and Canonici, MM and Barbugli, PA and Klein, MI}, title = {Distinct Agents Induce Streptococcus mutans Cells with Altered Biofilm Formation Capacity.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0065022}, pmid = {35862994}, issn = {2165-0497}, mesh = {Biofilms ; Chlorhexidine/metabolism/pharmacology ; *Dental Caries ; Humans ; Phosphopyruvate Hydratase/metabolism ; Polysaccharides, Bacterial/metabolism ; RNA, Ribosomal, 16S ; *Streptococcus mutans/metabolism ; }, abstract = {Dental caries is a multifactorial biofilm- and sugar-dependent disease. This study investigated the influence of different agents on the induction of surviving Streptococcus mutans cells after successive treatment cycles and characterized the biofilms formed by these cells recovered posttreatment. The agents (with their main targets listed in parentheses) were compound 1771 (lipoteichoic acids), 4' hydroxychalcone (exopolysaccharides), myricetin (exopolysaccharides), tt-farnesol (cytoplasmatic membrane), sodium fluoride (enolase-glycolysis), chlorhexidine (antimicrobial), and vehicle. Recovered cells from biofilms were generated from exposure to each agent during 10 cycles of consecutive treatments (modeled on a polystyrene plate bottom). The recovered cell counting was different for each agent. The recovered cells from each group were grown as biofilms on saliva-coated hydroxyapatite discs (culture medium with sucrose/starch). In S. mutans biofilms formed by cells recovered from biofilms previously exposed to compound 1771, 4' hydroxychalcone, or myricetin, cells presented higher expression of the 16S rRNA, gyrA (DNA replication and transcription), gtfB (insoluble exopolysaccharides), and eno (enolase-glycolysis) genes and lower quantities of insoluble dry weight and insoluble exopolysaccharides than those derived from other agents. These findings were confirmed by the smaller biovolume of bacteria and/or exopolysaccharides and the biofilm distribution (coverage area). Moreover, preexposure to chlorhexidine increased exopolysaccharide production. Therefore, agents with different targets induce cells with distinct biofilm formation capacities, which is critical for developing formulations for biofilm control. IMPORTANCE This article addresses the effect of distinct agents with distinct targets in the bacterial cell (cytoplasmatic membrane and glycolysis), the cell's extracellular synthesis of exopolysaccharides that are important for cariogenic extracellular matrix construction and biofilm buildup in the generation of cells that persisted after treatment, and how these cells form biofilms in vitro. For example, if preexposure to an agent augments the production of virulence determinants, such as exopolysaccharides, its clinical value may be inadequate. Modification of biofilm formation capacity after exposure to agents is critical for the development of formulations for biofilm control to prevent caries, a ubiquitous disease associated with biofilm and diet.}, } @article {pmid35862729, year = {2022}, author = {Naito, M and Shoji, M and Sato, K and Nakayama, K}, title = {Insertional Inactivation and Gene Complementation of Prevotella intermedia Type IX Secretion System Reveals Its Indispensable Roles in Black Pigmentation, Hemagglutination, Protease Activity of Interpain A, and Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {204}, number = {8}, pages = {e0020322}, pmid = {35862729}, issn = {1098-5530}, support = {JP17K19769//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; }, mesh = {Bacterial Proteins/metabolism ; Bacterial Secretion Systems/metabolism ; Base Composition ; Biofilms ; *Cysteine Proteases/genetics ; *Hemagglutination ; Humans ; Phylogeny ; Pigmentation ; Prevotella intermedia/genetics/metabolism ; RNA, Ribosomal, 16S ; Sequence Analysis, DNA ; Virulence Factors/genetics ; }, abstract = {Prevotella intermedia, a Gram-negative oral anaerobic bacterium, is frequently isolated from the periodontal pockets of patients with chronic periodontitis. In recent years, the involvement of the bacterium in respiratory tract infections as well as in oral infections has been revealed. P. intermedia possesses several potent virulence factors, such as cysteine proteinase interpain A encoded by the inpA gene. The genome of P. intermedia carries genes of the type IX secretion system (T9SS), which enables the translocation of virulence factors across the outer membrane in several pathogens belonging to the phylum Bacteroidetes; however, it is still unclear whether the T9SS is functional in this microorganism. Recently, we performed targeted mutagenesis in the strain OMA14 of P. intermedia. Here, we successfully obtained mutants deficient in inpA and the T9SS component genes porK and porT. None of the mutants exhibited protease activity of interpain A. The porK and porT mutants, but not the inpA mutant, showed defects in colony pigmentation, hemagglutination, and biofilm formation. We also obtained a complemented strain for the porK gene that recovered all the above abilities. These results indicate that T9SS functions in P. intermedia and that interpain A is one of the T9SS cargo proteins. IMPORTANCE The virulence factors of periodontal pathogens such as Prevotella intermedia have not been elucidated. Using our established procedure, we succeeded in generating type IX secretion system mutants and gene complementation strains that might transfer virulence factors to the bacterial surface. The generated strains clearly indicate that T9SS in P. intermedia is essential for colonial pigmentation, hemagglutination, and biofilm formation. These results indicated that interpain A is a T9SS cargo protein.}, } @article {pmid35861526, year = {2022}, author = {Nie, M and Dong, Y and Cao, Q and Zhao, D and Ji, S and Huang, H and Jiang, M and Liu, G and Liu, Y}, title = {CRISPR Contributes to Adhesion, Invasion, and Biofilm Formation in Streptococcus agalactiae by Repressing Capsular Polysaccharide Production.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0211321}, pmid = {35861526}, issn = {2165-0497}, mesh = {Biofilms ; CRISPR-Cas Systems ; *Operon ; Polysaccharides ; *Streptococcus agalactiae/genetics ; Virulence ; }, abstract = {The clustered regularly interspaced palindromic repeat (CRISPR)-associated (Cas) system functions classically as a prokaryotic defense system against invading mobile genetic elements, such as phages, plasmids, and viruses. Our previous study revealed that CRISPR deletion caused increased transcription of capsular polysaccharide (CPS) synthesis-related genes and severely attenuated virulence in the hypervirulent piscine Streptococcus agalactiae strain GD201008-001. Here, we found that CRISPR deficiency resulted in reduced adhesion, invasion, and biofilm formation abilities in this strain by upregulating the production of CPS. However, enhanced CPS production was not responsible for the attenuated phenotype of the ΔCRISPR mutant. RNA degradation assays indicated that inhibited transcription of the cps operon by CRISPR RNA (crRNA) was not due to the base pairing of the crRNA with the cps mRNA but to the repression of the promoter activity of cpsA, which is a putative transcriptional regulator of the capsule locus. IMPORTANCE Beyond protection from invading nucleic acids, CRISPR-Cas systems have been shown to have an important role in regulating bacterial endogenous genes. In this study, we demonstrate that crRNA inhibits the transcription of the cps operon by repressing the activity of promoter PcpsA, leading to increases in the abilities of adhesion, invasion, and biofilm formation in S. agalactiae. This study highlights the regulatory role of crRNA in bacterial physiology and provides a new explanation for the mechanism of crRNA-mediated endogenous gene regulation in S. agalactiae.}, } @article {pmid35861322, year = {2022}, author = {Pradeep, S and Arratia, PE}, title = {To biofilm or not to biofilm.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {35861322}, issn = {2050-084X}, mesh = {Bacteria ; *Biofilms ; *Quorum Sensing ; }, abstract = {A new model helps to predict under which conditions a species of bacteria will switch to a static lifestyle.}, } @article {pmid35861217, year = {2022}, author = {Aksoy, N and Vatansever, C and Zengin Ersoy, G and Adakli Aksoy, B and Fışgın, T}, title = {The effect of biofilm inhibitor N-acetylcysteine on the minimum inhibitory concentration of antibiotics used in Gram-negative bacteria in the biofilm developed on catheters.}, journal = {The International journal of artificial organs}, volume = {45}, number = {10}, pages = {865-870}, doi = {10.1177/03913988221112969}, pmid = {35861217}, issn = {1724-6040}, mesh = {Acetylcysteine/pharmacology ; Amikacin ; *Anti-Bacterial Agents/pharmacology ; Biofilms ; Catheters ; Cefepime/pharmacology ; Ceftazidime/pharmacology ; Child ; *Colistin/pharmacology ; Escherichia coli ; Gram-Negative Bacteria ; Humans ; Meropenem/pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, abstract = {The study determined the effect of N-acetylcysteine (NAC) on the susceptibility of various antibiotics used to treat Gram-negative catheter-related infection in isolates obtained from pediatric patients admitted to the hematology and oncology department of Medical Park Bahçelievler hospital in Istanbul, Turkey. Biofilms were created in vitro utilizing clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida, and Proteus mirabilis. 24 h old biofilms were developed on 96-well plate with strains and the minimum biofilm inhibitory concentration (MBIC) of six antibiotics were measured before and after the addition of 75 mg/ml N-acetylcysteine with microplate reader at 450 nm after crystal violet assay. The addition of NAC reduce the MBIC of cefepime, ceftazidime, colistin, meropenem from (16, 16, 8, 4 μg/ml) to (8, 4, 4, 2 μg/ml) respectively in E. coli (isolate 1). In P. aeruginosa (isolate 4), the MBIC of amikacin, ceftazidime, meropenem (64, 32, and 32 μg/ml) reduced to (8, 1, and 0.5 μg/ml) respectively. MBIC of cefepime, colistin, meropenem (32, 16,and 16 μg/ml) reduced to (2, 2,and 0.5 μg/ml) respectively in P. putida (isolate 5). In P. mirabilis (isolate 6), MBIC of amikacin, cefepime, ceftazidime, colisitin and meropenem (64, 128, 32, 4, and 32 μg/ml) reduced to (8, 8, 1, 1, 4 μg/ml). NAC in combination therapy can practically reduce the MBIC of antibiotics used to treat Gram negative bacteria that develop biofilm in medical catheters. As a result, these combinations can be considered as an essential alternative for increasing the antibiotic susceptibility of pathogenic microorganisms and thus increasing treatment success rates.}, } @article {pmid35861103, year = {2022}, author = {Albariño, RJ and Closs, GP and Matthaei, CD and Townsend, CR and Zamorano, D}, title = {Substrate size modifies stream grazer-biofilm interactions in the presence of invertivorous fish.}, journal = {Ecology}, volume = {103}, number = {12}, pages = {e3828}, pmid = {35861103}, issn = {1939-9170}, mesh = {Animals ; *Rivers ; *Ecosystem ; Invertebrates ; Trout ; Biofilms ; }, abstract = {When herbivore abundance is controlled by predators there may be an indirect positive effect on primary producers due to reduced grazing pressure, but the potential of predation refuges to modify such trophic cascades has rarely been studied. By experimentally manipulating substrate particle size and fish predation regime, we assessed the outcome of invertebrate grazer-biofilm interactions in streams. Locations at the center of larger substrate particles were predicted to pose a higher predation risk, and therefore be subjected to a lower grazing pressure. In our 52-day experiment in a New Zealand stream, small-sized substrates (terracotta tiles) remained virtually free of periphyton across their entire upper surface, whereas a thick periphyton mat was formed across large tiles with only edges remaining free. In channels containing fish (either native Galaxias vulgaris or exotic Salmo trutta), grazing on tiles was lower than in the absence of fish. A preference for grazing near to the edge of tiles was clearest in fish channels but was also evident even in the absence of fish, probably reflecting fish presence and/or fish kairomones in the stream from where the colonizing invertebrates had been derived. Total grazer density was similar across treatments with or without fish, suggesting that our results can be explained mostly by changes in the behavior of grazers. We suggest that refuge availability, interacting with grazer predator-avoidance behavior, may produce a context-dependent patchwork of trophic cascades in streams and other ecosystems.}, } @article {pmid35858930, year = {2022}, author = {Henriksen, NNSE and Hansen, MF and Kiesewalter, HT and Russel, J and Nesme, J and Foster, KR and Svensson, B and Øregaard, G and Herschend, J and Burmølle, M}, title = {Biofilm cultivation facilitates coexistence and adaptive evolution in an industrial bacterial community.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {59}, pmid = {35858930}, issn = {2055-5008}, mesh = {Bacteria ; *Biofilms ; *Lactococcus lactis/genetics ; }, abstract = {The majority of ecological, industrial and medical impacts of bacteria result from diverse communities containing multiple species. This diversity presents a significant challenge as co-cultivation of multiple bacterial species frequently leads to species being outcompeted and, with this, the possibility to manipulate, evolve and improve bacterial communities is lost. Ecological theory predicts that a solution to this problem will be to grow species in structured environments, which reduces the likelihood of competitive exclusion. Here, we explored the ability of cultivation in a structured environment to facilitate coexistence, evolution, and adaptation in an industrially important community: Lactococcus lactis and Leuconostoc mesenteroides frequently used as dairy starter cultures. As commonly occurs, passaging of these two species together in a liquid culture model led to the loss of one species in 6 of 20 lineages (30%). By contrast, when we co-cultured the two species as biofilms on beads, a stable coexistence was observed in all lineages studied for over 100 generations. Moreover, we show that the co-culture drove evolution of new high-yield variants, which compared to the ancestor grew more slowly, yielded more cells and had enhanced capability of biofilm formation. Importantly, we also show that these high-yield biofilm strains did not evolve when each species was passaged in monoculture in the biofilm model. Therefore, both co-culture and the biofilm model were conditional for these high-yield strains to evolve. Our study underlines the power of ecological thinking-namely, the importance of structured environments for coexistence-to facilitate cultivation, evolution, and adaptation of industrially important bacterial communities.}, } @article {pmid35858688, year = {2022}, author = {Sudan, S and Li, J}, title = {Dispersal of pathogen-associated multispecies biofilm by novel probiotic Bacillus subtilis in a contact-dependent manner.}, journal = {Journal of applied microbiology}, volume = {133}, number = {4}, pages = {2501-2515}, doi = {10.1111/jam.15721}, pmid = {35858688}, issn = {1365-2672}, support = {030275//Ontario Ministry of Agriculture, Food and Rural Affairs/ ; //Ministry of Agriculture/ ; 053878//Swine Innovation Porc/ ; //University of Guelph/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacillus subtilis/genetics ; Biofilms ; Gentian Violet ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; *Probiotics/pharmacology ; RNA, Messenger ; }, abstract = {AIMS: Biofilms are involved in pathogenesis of various bacterial infections. Treatment of biofilm-related bacterial infection remains a major challenge due to the reduced efficacy of antibiotics and associated antibiotic resistance. Given the high prevalence of Enterotoxigenic Escherichia coli (ETEC), Salmonella Typhimurium (S. Typhimurium) and methicillin-resistant Staphylococcus aureus (MRSA)-related infections and associated drug resistance, it is imperative to develop alternative strategies for treatment and prevention. The current study investigated antibiofilm activity of a recently isolated Bacillus subtilis (B. subtilis-9) against these pathogens.

METHODS AND RESULTS: Crystal violet staining showed that treatment with B. subtilis-9 significantly reduced biofilm biomass of ETEC (60%-80%), S. Typhimurium (68%-73%) and MRSA (66%-82%). In addition, B. subtilis-9 significantly reduced pre-formed biofilm biomass of ETEC (59%), S. Typhimurium (62%), MRSA (65%) and multispecies (58%). Fluorescence microscopy revealed that B. subtilis-9 treatment significantly reduced the thickness of biofilm and viability of the embedded bacteria. Additionally, B. subtilis-9 significantly reduced planktonic cell growth of ETEC (92%), S. Typhimurium (94%) and MRSA (93%). Interestingly, transwell assay showed that B. subtilis-9 exhibited antibiofilm properties in a cell-to-cell contact-dependent manner and significantly reduced mRNA expression of biofilm-related genes, bssS, luxS and ihfB in ETEC.

CONCLUSION: Novel B. subtilis-9 exhibits a strong inhibitory activity against ETEC, S. Typhimurium and MRSA biofilm formation and adhesion to abiotic surfaces. With further investigations, our study could bring forward a novel Bacillus-based probiotic intervention strategy to combat pathogenic biofilms, in clinical and agricultural settings.

Probiotic bacteria propose a potential alternative in combating biofilm-related infections, however, data on the efficacy and strain selection are limited. Data from this study are critical in further developing Bacillus-based novel probiotic applications that may reduce the use of antibiotics in biofilm-related infections in humans and animals.}, } @article {pmid35857530, year = {2023}, author = {Virdee, SS and Albaaj, FS and Grant, MM and Walmsley, D and Camilleri, J and Cooper, PR and Tomson, PL}, title = {Antimicrobial Efficacy of Different Irrigant Solutions Using a Novel Biofilm Model: An In Vitro Confocal Laser Scanning Microscopy Experiment.}, journal = {The European journal of prosthodontics and restorative dentistry}, volume = {31}, number = {1}, pages = {50-58}, doi = {10.1922/EJPRD_2419Virdee09}, pmid = {35857530}, issn = {0965-7452}, mesh = {Edetic Acid ; *Root Canal Irrigants ; Biofilms ; *Anti-Infective Agents ; Sodium Hypochlorite ; Microscopy, Confocal ; Dental Pulp Cavity ; Root Canal Preparation ; }, abstract = {AIM: To determine the ability of different irrigation solutions to biomechanically remove Enterococcus faecalis biofilm from a novel artificial root canal model during chemomechanical preparation.

METHODS: High resolution micro-computer-tomography scans of a mandibular molar's mesial root were used to produce 50 identical 3D-printed resin root canal models. These were cultured with E.faecalis over seven days to generate biofilm and subjected to chemomechanical preparation using: saline; 17% ethylenediaminetetraacetic acid (EDTA) or 2% sodium hypochlorite (NaOCl) alongside positive/negative controls (n = 10). Canals were prepared to 40/.06 taper, with 1 mL irrigation between instruments, followed by 5 mL penultimate rinse, 30 s ultrasonic activation and 5 mL final rinse. Residual biofilm volume (pixels) was determined following immunofluorescent staining and confocal-laser-scanning-microscopy imaging. Statistical comparisons were made using Kruskal-Wallis with post-hoc Dunn's tests (α ⟨0.05).

RESULTS: In all canal thirds, the greatest biofilm removal was observed with NaOCl, followed by EDTA and saline. The latter had significantly higher E.faecalis counts than NaOCl and EDTA (P ⟨0.01). However, no statistical differences were found between EDTA and NaOCl or saline and positive controls (P ⟩0.05).

CONCLUSIONS: Within limitations of this model, 17% EDTA was found to be as effective as 2% NaOCl at eradicating E.faecalis biofilm following chemomechanical preparation. Further investigations with multi-species biofilms are encouraged.}, } @article {pmid35856657, year = {2022}, author = {Bastos, RW and Akiyama, D and Dos Reis, TF and Colabardini, AC and Luperini, RS and de Castro, PA and Baldini, RL and Fill, T and Goldman, GH}, title = {Secondary Metabolites Produced during Aspergillus fumigatus and Pseudomonas aeruginosa Biofilm Formation.}, journal = {mBio}, volume = {13}, number = {4}, pages = {e0185022}, pmid = {35856657}, issn = {2150-7511}, support = {R01 AI153356/AI/NIAID NIH HHS/United States ; }, mesh = {Aspergillus fumigatus ; Biofilms ; *Cystic Fibrosis ; *Gliotoxin ; Humans ; Hypoxia ; Phenazines/metabolism/pharmacology ; Pseudomonas aeruginosa/metabolism ; }, abstract = {In cystic fibrosis (CF), mucus plaques are formed in the patient's lungs, creating a hypoxic condition and a propitious environment for colonization and persistence of many microorganisms. There is clinical evidence showing that Aspergillus fumigatus can cocolonize CF patients with Pseudomonas aeruginosa, which has been associated with lung function decline. P. aeruginosa produces several compounds with inhibitory and antibiofilm effects against A. fumigatus in vitro; however, little is known about the fungal compounds produced in counterattack. Here, we annotated fungal and bacterial secondary metabolites (SM) produced in mixed biofilms under normoxia and hypoxia conditions. We detected nine SM produced by P. aeruginosa. Phenazines and different analogs of pyoverdin were the main compounds produced by P. aeruginosa, and their secretion levels were increased by the fungal presence. The roles of the two operons responsible for phenazine production (phzA1 and phzA2) were also investigated, and mutants lacking one of those operons were able to produce partial sets of phenazines. We detected a total of 20 SM secreted by A. fumigatus either in monoculture or in coculture with P. aeruginosa. All these compounds were secreted during biofilm formation in either normoxia or hypoxia. However, only eight compounds (demethoxyfumitremorgin C, fumitremorgin, ferrichrome, ferricrocin, triacetylfusigen, gliotoxin, gliotoxin E, and pyripyropene A) were detected during biofilm formation by the coculture of A. fumigatus and P. aeruginosa under normoxia and hypoxia conditions. Overall, we showed how diverse SM secretion is during A. fumigatus and P. aeruginosa mixed culture and how this can affect biofilm formation in normoxia and hypoxia. IMPORTANCE The interaction between Pseudomonas aeruginosa and Aspergillus fumigatus has been well characterized in vitro. In this scenario, the bacterium exerts a strong inhibitory effect against the fungus. However, little is known about the metabolites produced by the fungus to counterattack the bacteria. Our work aimed to annotate secondary metabolites (SM) secreted during coculture between P. aeruginosa and A. fumigatus during biofilm formation in both normoxia and hypoxia. The bacterium produces several different types of phenazines and pyoverdins in response to presence of the fungus. In contrast, we were able to annotate 29 metabolites produced during A. fumigatus biofilm formation, but only 8 compounds were detected during biofilm formation by the coculture of A. fumigatus and P. aeruginosa upon either normoxia or hypoxia. In conclusion, we detected many SM secreted during A. fumigatus and P. aeruginosa biofilm formation. This analysis provides several opportunities to understand the interactions between these two species.}, } @article {pmid35856452, year = {2023}, author = {Parween, F and Yadav, P and Singh, K and Gupta, RD}, title = {Production of highly soluble native human paraoxonase 2 with potential anti-biofilm property.}, journal = {Preparative biochemistry & biotechnology}, volume = {53}, number = {5}, pages = {465-474}, doi = {10.1080/10826068.2022.2101000}, pmid = {35856452}, issn = {1532-2297}, mesh = {Humans ; *Aryldialkylphosphatase/metabolism ; *Biofilms ; Quorum Sensing ; }, abstract = {Paraoxonase 2 (PON2) is considered as a potential anti-biofilm agent due to the highest lactonase activity among the PON family members implicating quorum quenching in gram-negative bacteria. However, PON2 is expressed mostly in insoluble fractions in the bacterial expression host which limits its application as an anti-biofilm agent. Therefore, obtaining the native human PON2 (HuPON2) protein in soluble form, better protein yield, stability, and enzymatic activities is essential. In this study, procedures for obtaining a high yield of the native form of HuPON2 in soluble and active forms were optimized. Guanidinium hydrochloride solubilized the HuPON2 protein, however, it is lethal for several bacteria, and thus a major problem for studying the various downstream application of the protein. Therefore, another refolding process for native HuPON2 was optimized. Owing to the promiscuous nature of HuPON2, we hypothesized that it could inhibit the biofilm formation in Mycobacterium smegmatis also. Interestingly, we observed a significant inhibition of the biofilm formation by HuPON2_Rf. However, the primary target of HuPON2 and the probable mechanism behind the quorum quenching in M. smegmatis need to be further explored, which would help widen the scope of HuPON2 as a potential anti-biofilm agent beyond the gram-negative bacteria.}, } @article {pmid35855760, year = {2022}, author = {Huang, S and He, J and Zhang, Y and Su, L and Tong, L and Sun, Y and Zhou, M and Chen, Z}, title = {The Correlation Between Biofilm-Forming Ability of Community-Acquired Methicillin-Resistant Staphylococcus aureus Isolated from the Respiratory Tract and Clinical Characteristics in Children.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {3657-3668}, pmid = {35855760}, issn = {1178-6973}, abstract = {OBJECTIVE: This study aimed to investigate the biofilm-forming ability, molecular typing, and antimicrobial resistance of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strains isolated from the respiratory tract of children and their correlation with clinical characteristics.

METHODS: All CA-MRSA strains were isolated from hospitalized children, and their presentation, molecular typing, antimicrobial susceptibility, and biofilm formation were investigated. The clinical characteristics were compared between the strong and weak biofilm producer groups.

RESULTS: Fifty-three CA-MRSA strains were isolated from the respiratory samples of 53 children, with nearly half of them being young infants (0-12 months). Approximately, 88.7% (47/53) of the isolates were resistant to four or more antibiotics, mainly β-lactam antibiotics, lincosamides, and macrolides. Twelve sequence types (STs) and 20 subtypes of staphylococcal protein A (spa) typing were identified, with ST59-t437 (39.6%, 21/53) as the predominant subtype. All strains showed the ability to form biofilms. When compared to children with weak biofilm-forming CA-MRSA strains, those with strong biofilm-forming strains had higher proportions of lower respiratory tract infections (LRTI) (88.5% vs 59.3%), obvious cough symptoms (84.6% vs 51.9%), and severe chest imaging manifestations (76.9% vs 37.0%). Furthermore, a strong biofilm-forming ability significantly increased the risk of prolonged cough in children with LRTI (44.4% vs 14.3%), and a positive correlation between the duration of cough and the extent of biofilm formation was observed. Medical history investigation revealed that the strong biofilm-forming group had a much higher percentage of macrolides intake than the weak biofilm-forming group in the last month before admission (61.5% vs 14.8%).

CONCLUSION: ST59-t437 was the most prevalent clone in CA-MRSA respiratory isolates among the hospitalized children. All CA-MRSA strains formed biofilms. The stronger the biofilm-forming ability, the more serious and prolonged were the respiratory symptoms.}, } @article {pmid35852740, year = {2022}, author = {Wang, Y and Fu, M and Wu, B and Huang, M and Ma, T and Zang, H and Jiang, H and Zhang, Y and Li, C}, title = {Insight into biofilm-forming patterns: biofilm-forming conditions and dynamic changes in extracellular polymer substances.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {59}, pages = {89542-89556}, pmid = {35852740}, issn = {1614-7499}, support = {42071268//National Natural Science Foundation of China/ ; 41907117//National Natural Science Foundation of China/ ; }, mesh = {*Extracellular Polymeric Substance Matrix ; *Biofilms ; Bacteria ; Polymers ; }, abstract = {The microbial biofilm adheres to the surface of the carrier, which protects the pollutant-degrading bacteria and resists harsh environments; thus, research on biofilm-forming patterns will help promote the application of biofilms in wastewater treatment. Herein, univariate analysis and response surface methodology (RSM) confirmed that glucose and mannose at 3-5 g/L promoted biofilm formation. Notably, the microplate method demonstrated that compared to trivalent cations, divalent cations could more greatly enhance the activity (especially magnesium) of the biofilm matrix, and the period of biofilm formation in the three strains was divided into the following stages: initial attachment (0-10 h), microcolony (10-24 h), maturation (24-48 h), and dispersion (36-72 h). During maturation, large amounts of extracellular polysaccharides (EPs) and extracellular DNA (eDNA) were distributed in the extracellular and intracellular spaces, respectively, as observed by super-resolution structured illumination microscopy (SR-SIM). This study enhances the understanding of the characteristics and patterns of biofilm formation and can facilitate the application of biofilms in wastewater treatment.}, } @article {pmid35852317, year = {2022}, author = {Okuda, KI and Yamada-Ueno, S and Yoshii, Y and Nagano, T and Okabe, T and Kojima, H and Mizunoe, Y and Kinjo, Y}, title = {Small-Molecule-Induced Activation of Cellular Respiration Inhibits Biofilm Formation and Triggers Metabolic Remodeling in Staphylococcus aureus.}, journal = {mBio}, volume = {13}, number = {4}, pages = {e0084522}, pmid = {35852317}, issn = {2150-7511}, mesh = {Aminoglycosides/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Respiration ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections ; Staphylococcus aureus/genetics ; Vitamin K 2/pharmacology ; }, abstract = {Staphylococcus aureus, a major pathogen of community-acquired and nosocomial-associated infections, forms biofilms consisting of extracellular matrix-embedded cell aggregates. S. aureus biofilm formation on implanted medical devices can cause local and systemic infections due to the dispersion of cells from the biofilms. Usually, conventional antibiotic treatments are not effective against biofilm-related infections, and there is no effective treatment other than removing the contaminated devices. Therefore, the development of new therapeutic agents to combat biofilm-related infections is urgently needed. We conducted high-throughput screening of S. aureus biofilm inhibitors and obtained a small compound, JBD1. JBD1 strongly inhibits biofilm formation of S. aureus, including methicillin-resistant strains. In addition, JBD1 activated the respiratory activity of S. aureus cells and increased the sensitivity to aminoglycosides. Furthermore, it was shown that the metabolic profile of S. aureus was significantly altered in the presence of JBD1 and that metabolic remodeling was induced. Surprisingly, these JBD1-induced phenotypes were blocked by adding an excess amount of the electron carrier menaquinone to suppress respiratory activation. These results indicate that JBD1 induces biofilm inhibition and metabolic remodeling through respiratory activation. This study demonstrates that compounds that enhance the respiratory activity of S. aureus may be potential leads in the development of therapeutic agents for chronic S. aureus-biofilm-related infections. IMPORTANCE Chronic infections caused by Staphylococcus aureus are characterized by biofilm formation, suggesting that methods to control biofilm formation may be of therapeutic value. The small compound JBD1 showed biofilm inhibitory activity and increased sensitivity to aminoglycosides and respiratory activity of S. aureus. Additionally, transcriptomic and metabolomic analyses demonstrated that JBD1 induced metabolic remodeling. All JBD1-induced phenotypes were suppressed by the extracellular addition of an excess amount of menaquinone, indicating that JBD1-mediated respiratory stimulation inhibits biofilm formation and triggers metabolic remodeling in S. aureus. These findings suggest a strategy for developing new therapeutic agents for chronic S. aureus infections.}, } @article {pmid35852222, year = {2022}, author = {Huang, Z and Qi, Z and Ding, X and Liu, C}, title = {N-chlorosuccinimide enhancing the antimicrobial effect of benzalkonium chloride on biofilm Pseudomonas aeruginosa and its interaction mechanisms.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {}, number = {}, pages = {1-8}, doi = {10.1080/10934529.2022.2095176}, pmid = {35852222}, issn = {1532-4117}, abstract = {This study investigated the influence of N-chlorosuccinimide (NCS) pretreatment on the antimicrobial effect of benzalkonium chloride (BZC, representative of QACs) against biofilm bacteria and its mechanisms. Results show that 0.04 - 0.07 mmol/L NCS pretreatment significantly increased the antimicrobial efficacy of 0.03 mmol/L BZC on biofilm cells by 30% - 70%. The main mechanisms involved membrane permeability, oxidative damage, and metabolic disorder. More precisely, NCS pretreatment increased the permeability of bacteria and reduced the activity of the electron transport system (ETS) and dehydrogenase (DHA). At the same time, the oxidative damage of both endogenous and exogenous ROS and the disorder of the antioxidant enzymes (superoxide dismutase and catalase) further improved their combined antibacterial ability. Moreover, NCS pretreatment greatly reduced the resistance of biofilm Pseudomonas aeruginosa to BZC. The findings of the study provide a new method to effectively enhance the antimicrobial efficiency of quaternary ammonium cationic surfactants (e.g., BZC) and reduce bacterial resistance, as well as a scientific guidance for the development of new antimicrobial products.}, } @article {pmid35851777, year = {2022}, author = {Pourhajibagher, M and Bahador, A}, title = {Physico-mechanical properties, antimicrobial activities, and anti-biofilm potencies of orthodontic adhesive containing cerium oxide nanoparticles against Streptococcus mutans.}, journal = {Folia medica}, volume = {64}, number = {2}, pages = {252-259}, doi = {10.3897/folmed.64.e60418}, pmid = {35851777}, issn = {1314-2143}, mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; Cerium ; *Dental Caries ; Dental Cements ; Humans ; *Nanoparticles ; Streptococcus mutans ; }, abstract = {White spot lesions around orthodontic brackets may lead to the formation of dental caries during and following fixed orthodontic treatment.}, } @article {pmid35851776, year = {2022}, author = {Georgiev, K and Filipov, I and Pecheva, A}, title = {Biofilm reactor calibration for in vitro investigation of composite biodegradation.}, journal = {Folia medica}, volume = {64}, number = {2}, pages = {248-251}, doi = {10.3897/folmed.64.e61540}, pmid = {35851776}, issn = {1314-2143}, mesh = {*Biofilms ; Calibration ; Humans ; *Microbiota ; Mouth ; Saliva ; }, abstract = {The majority of biodegradation studies of composite materials use simplified models of microbial biofilm despite the apparent diversity of the oral microbiota. The use of in vitro systems of "artificial mouth" design is a step towards clarifying the synergistic effect that microbial plaque and human saliva have on composite degradation.}, } @article {pmid35850461, year = {2022}, author = {Pourhajibagher, M and Bahador, A}, title = {Aptamer decorated emodin nanoparticles-assisted delivery of dermcidin-derived peptide DCD-1L: Photoactive bio-theragnostic agent for Enterococcus faecalis biofilm destruction.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {39}, number = {}, pages = {103020}, doi = {10.1016/j.pdpdt.2022.103020}, pmid = {35850461}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/therapeutic use ; Biofilms ; *Dermcidins/pharmacology ; *Emodin/pharmacology ; Enterococcus faecalis ; Indocyanine Green/pharmacology ; Lasers, Semiconductor/therapeutic use ; Molecular Docking Simulation ; *Nanoparticles ; *Photochemotherapy/methods ; Photosensitizing Agents/therapeutic use ; }, abstract = {BACKGROUND: Despite the high success rate of root canal treatment, failures are observed in a broad range of cases. Therefore, the need for novel approaches with the development of new generations of antimicrobial agents and intracellular drug delivery systems as adjunctive therapy is undeniable. In this study, we investigated the antimicrobial effects of antimicrobial photodynamic therapy (aPDT) using dermcidin‑derived peptide DCD‑1L loaded onto aptamer-functionalized emodin nanoparticles (Apt@EmoNp-DCD-1L) against Enterococcus faecalis as one of the most common bacteria involved in recurrent root canal treatment failures.

MATERIALS AND METHODS: Following preparation of EmoNp-DCD-1L, the binding of selected labeled Apt to EmoNp-DCD-1L was performed, followed by the specificity of Apt@EmoNp-DCD-1L to E. faecalis was determined. The antimicrobial potential of aPDT was then assessed after the determination of the minimum inhibitory concentration (MIC) of Apt@EmoNp-DCD-1L. The molecular docking analysis was conducted to evaluate the potential binding modes of EmoNp to the proteins involved in E. faecalis pathogenesis. Eventually, the anti-virulence capacity of Apt@EmoNp-DCD-1L-mediated aPDT was investigated via quantitative real-time PCR (qRT-PCR) assay following measurement of intracellular reactive oxygen species (ROS) generation.

RESULTS: The binding specificity of Apt@EmoNp-DCD-1L to E. faecalis was confirmed by flow cytometry. The results showed that the cell viability of E. faecalis exposed to aPDT groups employing the sub-MIC doses of Apt@EmoNp-DCD-1L (7.8 and 15.6 µM) was significantly reduced compared to the control group (P < 0.05). Also, Apt@EmoNp-DCD-1L in combination with a blue laser light was capable of enhancing the anti-biofilm activity of aPDT against E. faecalis biofilm. Data obtained from the qRT-PCR analysis showed significant downregulation in the expression level of genes involved in bacterial biofilm formation after exposure to aPDT (P < 0.05).

CONCLUSIONS: This in vitro study highlights that aPDT with the minimum concentration of Apt@EmoNp-DCD-1L can be considered as a targeted bio-theragnostic agent for the detection and elimination of E. faecalis in the dispersed and biofilm states.}, } @article {pmid35850296, year = {2022}, author = {Lan, M and Yang, P and Xie, L and Li, Y and Liu, J and Zhang, P and Zhang, P and Li, B}, title = {Start-up and synergistic nitrogen removal of partial nitrification and anoxic/aerobic denitrification in membrane aerated biofilm reactor.}, journal = {Environmental research}, volume = {214}, number = {Pt 2}, pages = {113901}, doi = {10.1016/j.envres.2022.113901}, pmid = {35850296}, issn = {1096-0953}, mesh = {Biofilms ; Bioreactors/microbiology ; *Denitrification ; Extracellular Polymeric Substance Matrix ; *Nitrification ; Nitrogen ; Sewage ; Wastewater ; }, abstract = {To reduce energy consumption and improve operational stability of traditional biological nitrogen removal (BNR) system, partial nitrification and anoxic/aerobic denitrification were synergistically implemented in membrane aerated biofilm reactor (MABR) by regulating DO and pH. The results indicated that the optimal DO, pH and C/N ratio were 1-2 mg/L, 9.0 and 4-7, respectively. The corresponding average organic removal rate (ORR), total nitrogen removal rate (TNRR) and nitrite accumulation rate (NAR) reached 324 gCOD・m[-3]・d[-1], 48 gN・m[-3]・d[-1] and 77.70%, respectively. Extracellular polymeric substance (EPS) content in biofilm was more abundant than that in inoculated sludge. Multiple aerobic denitrifiers were detected in the biofilm with the relative abundance of 11.19%-22.71%. AQUASIM simulation implied that the distribution and proportion of substrates and bacteria were significantly affected by DO and pH regulation. Overall, this study provided some important insights in the start-up and operation of synergistic nitrogen removal process in BNR system.}, } @article {pmid35850213, year = {2022}, author = {Tong, CY and Lew, JK and Derek, CJC}, title = {Algal extracellular organic matter pre-treatment enhances microalgal biofilm adhesion onto microporous substrate.}, journal = {Chemosphere}, volume = {307}, number = {Pt 1}, pages = {135740}, doi = {10.1016/j.chemosphere.2022.135740}, pmid = {35850213}, issn = {1879-1298}, mesh = {Biofilms ; *Diatoms ; Extracellular Polymeric Substance Matrix ; Fluorocarbon Polymers ; *Microalgae/metabolism ; Polysaccharides/metabolism ; Polyvinyls ; }, abstract = {Adhesive biocoating has microstructure composed of biomolecules to entrap viable cells in a stabilized matrix over exposed surfaces. Although marine benthic diatoms are a common group of algae excreting substantial amount of extracellular polymeric substances (EPS), studies regarding the utilization of these EPS are scarce. Using the soluble EPS derived from Navicula incerta and pre-deposition of it as a thin conditioning layer on microporous polyvinylidene fluoride (PVDF) membranes, the pre-coated surface was used to investigate the cell binding affinity of three marine microalgae, namely Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta. Microalgae actively engaged themselves on the pre-coated membranes which was 10 times greater than the initial cell adhesion degree. Soluble EPS is mainly comprised of polysaccharide while bounded EPS is mainly comprised of protein. On EPS pre-coated membranes, N. incerta released the least amount of bounded polysaccharides (<100 mg m[-2]) and vice versa for the other two because EPS production is usually maximized to assist cell adhesion onto unfavorable substrates. In stark contrast, when the adaptation period (first 6 h) ended, cells began to secrete more bounded protein for cell growth, and an increasing trend of protein content found in N. incerta has verified its optimal adaptation onto the biocoating itself. On pristine PVDF membranes, the adhesion degree was ranked in ascending order: C. fusiformis, N. incerta and A. coffeaeformis. Interestingly, after the pre-coating process, the order was reported as: A. coffeaeformis, N. incerta and C. fusiformis, but it should be noted that C. fusiformis demonstrated fluctuating cell colonization degree and bounded EPS production over time. In other words, the biofilm's susceptibility was confirmed since the cells latched loosely on the membranes rather than in a biofilm matrix. Biocoating enables uniform cell distribution and firmer biofilm growth, opening the door to vast future applications in environmental bioremediation and sensing.}, } @article {pmid35850068, year = {2022}, author = {Ding, M and Zhao, W and Zhang, X and Song, L and Luan, S}, title = {Charge-switchable MOF nanocomplex for enhanced biofilm penetration and eradication.}, journal = {Journal of hazardous materials}, volume = {439}, number = {}, pages = {129594}, doi = {10.1016/j.jhazmat.2022.129594}, pmid = {35850068}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms ; *Photochemotherapy/methods ; Photosensitizing Agents/chemistry/pharmacology ; }, abstract = {Bacterial biofilm is notorious for causing chronic infections, whose antibiotic treatment is bringing about severe multidrug resistance and environmental contamination. Stimuli-responsive nanocarriers have become encouraging materials to combat biofilm infections with high efficiency and low side effect. Herein, a charge-switchable and pH-responsive nanocomplex is fabricated via a facile aqueous one-pot zeolitic imidazolate framework-8 (ZIF-8) encapsulation of proteinase K (PK) and photosensitizer Rose Bengal (RB), for enzymatic and photodynamic therapies (PDT) against biofilm infections. Once encountering in acidic microenvironment, the surface charge of nanocomplex can switch self-adaptively from negative to positive, hence remarkably facilitating the biofilm penetration of nanocomplex. After acid-induced decomposition of nanocomplex, the released PK degrades biofilm matrix and loosens its structure, promoting diffusion of RB inside the biofilm. Afterwards, upon visible light illumination, the RB generates highly reactive oxygen species (ROS), which can readily and efficiently kill the remained bacteria even in the biofilm core. The charge-assisted penetration makes PK and RB fully functional, resulting in a cooperative effect concerning high biofilm eradication capacity, as testified by biofilm models both in vitro and in vivo. The green synthesis and good therapeutic performance of the nanocomplex manifests its considerable potential as a nontoxic and effective platform for biofilm treatment.}, } @article {pmid35849907, year = {2022}, author = {Lwin, HY and Aoki-Nonaka, Y and Matsugishi, A and Takahashi, N and Hiyoshi, T and Tabeta, K}, title = {Soybean peptide inhibits the biofilm of periodontopathic bacteria via bactericidal activity.}, journal = {Archives of oral biology}, volume = {142}, number = {}, pages = {105497}, doi = {10.1016/j.archoralbio.2022.105497}, pmid = {35849907}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms ; Fusobacterium nucleatum ; Humans ; Peptides/pharmacology ; Porphyromonas gingivalis ; *Soybeans ; }, abstract = {OBJECTIVE: This study aimed to clarify the antibacterial mechanism and antibiofilm effect of soybean-derived peptide BCBS-11 against periodontopathic bacteria.

DESIGN: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of BCBS-11 against Porphyromonas gingivalis (P. gingivalis), Fusobacterium nucleatum (F. nucleatum), and Streptococcus mitis (S. mitis) were determined for the antibacterial mechanism. The effect of BCBS-11 on membrane permeability and depolarization activity were investigated using propidium iodide (PI) staining and 3, 3'-dipropylthiadicarbocyanine iodide (DiSC3-(5)) analysis. Monospecies and multispecies biofilms were cultured on 96-well plates. The amount of biofilm was determined using crystal violet staining to determine the inhibition of biofilm formation and the eradication of established biofilm using BCBS-11. The cytotoxicity of BCBS-11 was evaluated using 3-(4, 5-Dimethylthiazol-2-yl)- 2, 5-diphenyltetrazolium bromide (MTT) assay.

RESULTS: The MIC and MBC indicated the bactericidal activity of BCBS-11 against P. gingivalis and F. nucleatum. The PI staining revealed that BCBS-11 disrupted the bacterial membrane integrity. The DiSC3-(5) analysis indicated that BCBS-11 depolarized the bacterial cytoplasmic membrane. These results indicate the antimicrobial action of BCBS-11 through membrane disruption and the collapse of membrane electrochemical gradient. BCBS-11 significantly inhibited the monospecies biofilm formation of P. gingivalis and F. nucleatum and also inhibited dual-species biofilm. BCBS-11 was not cytotoxic toward human oral epithelial cells.

CONCLUSIONS: BCBS-11 inhibits the monospecies and multispecies biofilm formation of P. gingivalis and F. nucleatum, and their bactericidal activity results from membrane disruption.}, } @article {pmid35849001, year = {2022}, author = {Tiba, AA and Tiba, A and Horvath, F and Huh, EY and Ford, AA and Arens, DK and Sarwar, TA and Hwang, YY}, title = {Effects of a Two-Step Silver Diamine Fluoride Varnish on Shear Bond Strength of Restorations, Dentin and Enamel Hardness, and Biofilm Formation.}, journal = {Military medicine}, volume = {}, number = {}, pages = {}, doi = {10.1093/milmed/usac216}, pmid = {35849001}, issn = {1930-613X}, support = {G2003//Naval Medical Research Unit-San Antonio/ ; }, abstract = {INTRODUCTION: Dental caries are a limiting factor in maintaining dental and medical readiness in the military. Untreated dental caries can lead to dire health consequences. Consistent and comprehensive access to dental care is often limited due to the intensive operational demands on our nation's warfighters. The standard of care for dental caries is a surgical model where diseased tooth tissue is surgically removed and restored with appropriate restorative materials. While effective, it is not practical in the military operational environment, especially under time constraints. Dental restoratives offer military personnel a simple and preventive treatment of dental caries and are suitable as self-applied first aids. The purpose of this study was to measure the shear bond strengths of two dental restorative materials to human teeth paired with two different fluoride treatments and the hardness and biofilm formation on teeth after applying the fluoride varnishes.

MATERIALS AND METHODS: Specimens were made of human molar teeth treated with each of the following four materials: glass ionomer cement GC Fuji II LC Capsules, Filtek Z250, Riva Star steps 1 and 2, or Mark3 NaF varnish. Step 1 of Riva Star consists of silver diamine fluoride and step 2 contains potassium iodide. On human molar slabs, 10 circular specimens of 5 cm in diameter were prepared with restoratives according to manufacturer procedures. Etch-Rite and a proprietary aluminum chloride-based cavity conditioner were used as etchants on tooth surfaces for the Filtek Z250 and glass ionomer cement, respectively. After at least 24 hours underwater, each assembly was removed, and the shear bond strength of the adhesive was measured according to International Organization for Standardization (ISO) 29022.The hardness was measured according to ISO 14233. Hardness measurements were performed before varnish application, then after storage in an incubator at 37 °C for 4 hours in a demineralization solution (pH = 4.5), and after 1 day in a mineralization solution (pH = 7). A crystal violet staining assay was used to measure biofilm formation of Streptococcus mutans bacteria on human molar teeth after the application of fluoride varnish.

RESULTS: We report a 16% increase in shear bond strength of the Filtek Z250/Riva Star coupled treatment compared to the Filtek Z250/Mark3 NaF coupled treatment. We also demonstrate a significant 84% decrease in bond strength with a GC Fuji II LC/Mark3 NaF treatment compared to control (P = .0002), while Riva Star remains statistically unchanged. Enamel and dentinal hardness are significantly improved when Riva Star is applied compared to NaF varnish. A 25%-35% (P < .0001) decrease in oral biofilm formation was observed on samples where a Riva Star or NaF varnish was applied.

CONCLUSIONS: Mechanical and antimicrobial testing indicated Riva Star, compared favorably with and in some cases, performed better in the laboratory than a Mark3 NaF varnish. Hardness measurements indicated Riva Star is more effective in dentin tubule occlusion compared to NaF varnish. Our findings help provide practical suggestions to dental treatment, particularly to the unique dental environments seen in the military. Riva Star may be used as an adjunctive treatment prior to placing a final restoration. This study supports the use of Riva Star in conjunction with GC Fuji II LC or Filtek Z250 restorative materials, making it a promising treatment in military dental applications.}, } @article {pmid35847069, year = {2022}, author = {Korzeniowski, P and Śliwka, P and Kuczkowski, M and Mišić, D and Milcarz, A and Kuźmińska-Bajor, M}, title = {Bacteriophage Cocktail Can Effectively Control Salmonella Biofilm in Poultry Housing.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {901770}, pmid = {35847069}, issn = {1664-302X}, abstract = {Salmonella enterica serovar Enteritidis (S. Enteritidis) is the major contaminant of poultry products, and its ability to form biofilms on produced food and poultry farm processing surfaces contributes to Salmonella transmission to humans. Bacteriophages have come under increasing interest for anti-Salmonella biofilm control. In this study, we used the three previously sequenced and described phages UPWr_S1, UPWr_S3, and UPWr_S4 and a phage cocktail, UPWr_S134, containing these three phages to degrade biofilms formed by two S. Enteritidis strains, 327 lux and ATCC 13076, in vitro. It was found that treatment with bacteriophages significantly reduced biofilm on a 96-well microplate (32-69%) and a stainless steel surface (52-98%) formed by S. Enteritidis 327 lux. The reduction of biofilm formed by S. Enteritidis ATCC 13076 in the 96-well microplate and on a stainless steel surface for bacteriophage treatment was in the range of 73-87% and 60-97%, respectively. Under laboratory conditions, an experimental model utilizing poultry drinkers artificially contaminated with S. Enteritidis 327 lux and treated with UPWr_S134 phage cocktail was applied. In in vitro trials, the phage cocktail significantly decreased the number of Salmonella on the surface of poultry drinkers. Moreover, the phage cocktail completely eradicated Salmonella from the abundant bacterial load on poultry drinkers in an experimentally infected chickens. Therefore, the UPWr_S134 phage cocktail is a promising candidate for Salmonella biocontrol at the farm level.}, } @article {pmid35846990, year = {2022}, author = {Pant, N and Miranda-Hernandez, S and Rush, C and Warner, J and Eisen, DP}, title = {Non-Antimicrobial Adjuvant Therapy Using Ticagrelor Reduced Biofilm-Related Staphylococcus aureus Prosthetic Joint Infection.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {927783}, pmid = {35846990}, issn = {1663-9812}, abstract = {Background: Prosthetic joint infection (PJI), frequently caused by Staphylococcus aureus, leads to a significant arthroplasty failure rate. Biofilm is a crucial virulence factor of S. aureus that is intrinsic to the pathogenesis of PJI. Biofilm-related infections are recalcitrant to antibiotic treatment. Surgical and antibiotic therapy could be combined with non-antibacterial adjuvants to improve overall treatment success. Ticagrelor, a P2Y12 receptor inhibitor antiplatelet drug, is known to have anti-staphylococcal antibacterial and antibiofilm activity. However, the molecular mechanism for ticagrelor's antibiofilm activity and its efficacy in the treatment of S. aureus PJI are unknown. Methods: To study the in vitro antibacterial and antibiofilm activity of ticagrelor, broth microdilution and crystal violet staining method were used. Ticagrelor's effect on the expression of S. aureus biofilm genes (icaA, icaD, ebps, fib, eno, and agr) was studied using the relative quantification method. To test ticagrelor's in vivo efficacy to treat S. aureus PJI, mice were randomized into five groups (n = 8/group): infected femoral implants treated with ticagrelor alone; infected implants treated with cefazolin alone; infected implants treated with ticagrelor and cefazolin; infected implants treated with phosphate buffer solution (PBS)-positive controls, and sterile implants-negative controls. Ticagrelor was administered orally from day 4 to day 7 post-surgery, while cefazolin was injected intravenously on day 7. Results: Ticagrelor, alone and with selected antibiotics, showed in vitro antibacterial and antibiofilm activity against S. aureus. Strain-specific downregulation of biofilm-related genes, fib, icaD, ebps, and eno, was shown. In an animal model of biofilm-related S. aureus PJI, ticagrelor alone and combined with cefazolin significantly reduced bacterial concentrations on the implants compared with the positive control group. Ticagrelor significantly reduced bacterial dissemination to periprosthetic tissue compared with the positive controls. Conclusion: Ticagrelor adjuvant therapy reduced S. aureus PJI in an animal model. However, this study is very preliminary to make a conclusion on the clinical implication of the findings. Based on the current results, more studies are recommended to better understand its implication.}, } @article {pmid35846965, year = {2022}, author = {Kankilic, B and Bayramli, E and Korkusuz, P and Eroglu, H and Sener, B and Mutlu, P and Korkusuz, F}, title = {Vancomycin Containing PDLLA and PLGA/β-TCP Inhibit Biofilm Formation but Do Not Stimulate Osteogenic Transformation of Human Mesenchymal Stem Cells.}, journal = {Frontiers in surgery}, volume = {9}, number = {}, pages = {885241}, pmid = {35846965}, issn = {2296-875X}, abstract = {AIMS: Chronic osteomyelitis, including implant-related prosthetic joint infection, is extremely difficult to cure. We develop vancomycin containing release systems from poly(d,l-lactide) (PDLLA) and poly(d,l-lactide-co-glycolide) (PLGA) composites with beta-tricalcium phosphate (β-TCP) to treat methicillin-resistant Staphylococcus aureus osteomyelitis. We ask whether vancomycin containing PDLLA/β-TCP and PLGA/β-TCP composites will prevent early biofilm formation, allow cell proliferation and osteogenic differentiation, and stimulate osteogenic signaling molecules in the absence of an osteogenic medium.

METHODS: Composites were produced and characterized with scanning electron microscopy. In vitro vancomycin release was assessed for 6 weeks. Biofilm prevention was calculated by crystal violet staining. Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and osteosarcoma cell (SaOS-2) proliferation and differentiation were assessed with water soluble tetrazolium salt and alkaline phosphatase (ALP) staining. Real-time quantitative polymerase chain reaction defined osteogenic signaling molecules for hBM-MSCs.

RESULTS: Totally, 3.1 ± 0.2 mg and 3.4 ± 0.4 mg vancomycin released from PDLLA/β-TCP and the PLGA/β-TCP composites, respectively, and inhibited early biofilm formation. hBM-MSCs and SaOS-2 cells proliferated on the composites and stimulated ALP activity of cells. Runt-related transcription factor 2 (RUNX2) and SRY-Box transcription Factor 9 (SOX9) expressions were, however, lower with composites when compared with control.

CONCLUSION: Vancomycin containing PDLLA/β-TCP and PLGA/β-TCP composites inhibited early biofilm formation and proliferated and differentiated hBM-MSCs and SaOS-2 cells, but osteogenesis-related RUNX2 and SOX9 transcription factors were not strongly expressed in the absence of an osteogenic medium for 14 days.}, } @article {pmid35846767, year = {2022}, author = {Tartor, YH and Elmowalid, GA and Hassan, MN and Shaker, A and Ashour, DF and Saber, T}, title = {Promising Anti-Biofilm Agents and Phagocytes Enhancers for the Treatment of Candida albicans Biofilm-Associated Infections.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {807218}, pmid = {35846767}, issn = {2235-2988}, mesh = {Animals ; Antifungal Agents/pharmacology ; Biofilms ; Candida ; Candida albicans ; *Candidiasis/microbiology ; Cattle ; Cetrimonium/pharmacology ; Fluconazole/pharmacology ; Microbial Sensitivity Tests ; *Oils, Volatile/pharmacology ; Phagocytes ; }, abstract = {Little is known about the interactions among phagocytes and antifungal agents and the antifungal immunomodulatory activities on Candida species biofilms. Here, inhibition of C. albicans biofilms and the interactions among biofilms and phagocytes alone or in combination with essential oils, biological, and chemical agents, or fluconazole were investigated. Biofilm formation by a panel of 28 C. albicans clinical isolates from hospitalized patients, birds, and cattle was tested. The anti-biofilm activities of cinnamon and clove oils, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and Enterococcus faecalis cell-free supernatant (CFS) in comparison with fluconazole were investigated using crystal violet and XTT reduction assays, expression of hypha-specific and hyphal regulator genes, and scanning electron microscopy (SEM) analysis. Of the tested C. albicans isolates, 15 of 28 (53.6%) were biofilm producers. Cinnamon followed by E. faecalis-CFS, SDS, and CTAB was the most effective inhibitors of planktonic C. albicans and biofilms. Fluconazole was an ineffective inhibitor of C. albicans biofilms. Sessile minimal inhibitory concentration (SMIC50) of cinnamon, SDS, CTAB, and E. faecalis-CFS downregulated the hypha-specific and regulator genes, albeit to various extents, when compared with untreated biofilms (P < 0.001). SEM analysis revealed disruption and deformity of three-dimensional structures in cinnamon oil-treated biofilms. C. albicans sessile cells within biofilm were less susceptible to phagocytosis than planktonic cells. The additive effects of phagocytes and the tested antifungals enabled phagocytes to engulf C. albicans cells rapidly in cinnamon, E. faecalis-CFS, or SDS-treated biofilms. No differences in anti-Candida or anti-biofilm eradication activities were detected among the tested isolates. Our findings reinforce the substantial anti-biofilm activity of cinnamon oil, SDS, and E. faecalis-CFS and provide new avenues for the development of novel anti-biofilm immunotherapies or antifungals that could be used prior to or during the management of cases with biofilm-associated infections.}, } @article {pmid35846761, year = {2022}, author = {Okae, Y and Nishitani, K and Sakamoto, A and Kawai, T and Tomizawa, T and Saito, M and Kuroda, Y and Matsuda, S}, title = {Estimation of Minimum Biofilm Eradication Concentration (MBEC) on In Vivo Biofilm on Orthopedic Implants in a Rodent Femoral Infection Model.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {896978}, pmid = {35846761}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Gentamicins/pharmacology ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Rats ; Rifampin/pharmacology ; Rodentia ; Vancomycin/pharmacology ; }, abstract = {The formation of a biofilm on the implant surface is a major cause of intractable implant-associated infection. To investigate the antibiotic concentration needed to eradicate the bacteria inside a biofilm, the minimum biofilm eradication concentration (MBEC) has been used, mostly against in vitro biofilms on plastic surfaces. To produce a more clinically relevant environment, an MBEC assay against biofilms on stainless-steel implants formed in a rat femoral infection model was developed. The rats were implanted with stainless steel screws contaminated by two Staphylococcus aureus strains (UAMS-1, methicillin-sensitive Staphylococcus aureus; USA300LAC, methicillin-resistant Staphylococcus aureus) and euthanized on days 3 and 14. Implants were harvested, washed, and incubated with various concentrations (64-4096 μg/mL) of gentamicin (GM), vancomycin (VA), or cefazolin (CZ) with or without an accompanying systemic treatment dose of VA (20 μg/mL) or rifampicin (RF) (1.5 μg/mL) for 24 h. The implant was vortexed and sonicated, the biofilm was removed, and the implant was re-incubated to determine bacterial recovery. MBEC on the removed biofilm and implant was defined as in vivo MBEC and in vivo implant MBEC, respectively, and the concentrations of 100% and 60% eradication were defined as MBEC100 and MBEC60, respectively. As for in vivo MBEC, MBEC100 of GM was 256-1024 μg/mL, but that of VA and CZ ranged from 2048-4096 μg/mL. Surprisingly, the in vivo implant MBEC was much higher, ranging from 2048 μg/mL to more than 4096 μg/mL. The addition of RF, not VA, as a secondary antibiotic was effective, and MBEC60 on day 3 USA300LAC biofilm was reduced from 1024 μg/mL with GM alone to 128 μg/mL in combination with RF and the MBEC60 on day 14 USA300LAC biofilm was reduced from 2048 μg/mL in GM alone to 256 μg/mL in combination with RF. In conclusion, a novel MBEC assay for in vivo biofilms on orthopedic implants was developed. GM was the most effective against both methicillin-sensitive and methicillin-resistant Staphylococcus aureus, in in vivo biofilms, and the addition of a systemic concentration of RF reduced MBEC of GM. Early initiation of treatment is desired because the required concentration of antibiotics increases with biofilm maturation.}, } @article {pmid35843452, year = {2022}, author = {Li, H and Wu, Y and Tang, Y and Fang, B and Luo, P and Yang, L and Jiang, Q}, title = {A manganese-oxidizing bacterium-Enterobacter hormaechei strain DS02Eh01: Capabilities of Mn(II) immobilization, plant growth promotion and biofilm formation.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {309}, number = {}, pages = {119775}, doi = {10.1016/j.envpol.2022.119775}, pmid = {35843452}, issn = {1873-6424}, mesh = {Biofilms ; Enterobacter/metabolism ; *Manganese/metabolism ; *Manganese Compounds ; Oxidation-Reduction ; Oxides/metabolism ; }, abstract = {While biogenic Mn oxides (BioMnOx) generated by Mn(II)-oxidizing bacteria (MOB) have attracted increasing attention, a MOB strain isolated from Mn-polluted sediments was identified and assigned as Enterobacter hormaechei DS02Eh01. Its Mn(II) immobilization activity, plant growth-promoting traits, and biofilm formation capability were investigated. The results showed that strain DS02Eh01 was found to be able to tolerate Mn(II) up to 122 mM. The strain immobilized Mn(II) in aquatic media mainly through extracellular adsorption, bio-oxidation and pH-induced precipitation as well as manganese oxidation. DS02Eh01-derived BioMnOx are negatively charged and have a larger specific surface area (86.70 m[2]/g) compared to the previously reported BioMnOx. The strain can immobilize Mn(II) at extreme levels, for instance, when it was exposed to 20 mM Mn(II), about 59% of Mn(II) were found immobilized and 17% of Mn(II) were converted to MnOx. The SEM and TEM observation revealed that the DS02Eh01-derived BioMnOx were aggregates doped with granules and microbial pellets. The precipitated Mn(II) and the Mn(III)/Mn(IV) oxides co-existed in BioMnOx, in which Mn(II) and Mn(IV) were found dominant with Mn(II) accounting for 49.6% and Mn(IV) accounting for 41.3%. DS02Eh01 possesses plant growth-promoting traits and biofilm formation capacity even under Mn(II) exposure. Mn(II) exposure at 5 mM was found to stimulate strain DS02Eh01 to form biofilms, from which, the extracted EPS was mainly composed of aromatic proteins. This study reveals that E. hormaechei strain DS02Eh01 possesses the potential in environmental ecoremediation via coupling processes of macrophytes extraction, biochemical immobilization and biosorption.}, } @article {pmid35843279, year = {2022}, author = {Dey, N and Vickram, S and Thanigaivel, S and Kamatchi, C and Subbaiya, R and Karmegam, N and Govarthanan, M}, title = {Graphene materials: Armor against nosocomial infections and biofilm formation - A review.}, journal = {Environmental research}, volume = {214}, number = {Pt 2}, pages = {113867}, doi = {10.1016/j.envres.2022.113867}, pmid = {35843279}, issn = {1096-0953}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *COVID-19 ; *Cross Infection/epidemiology/prevention & control ; *Graphite ; Humans ; *Metal Nanoparticles ; Silver ; }, abstract = {Graphene has revolutionized the field of energy and storage sectors. Out of the total number of nosocomial infections diagnosed all around the world, the majority of the cases (around 70%) are found to be due to the medical device or assistance utilized while treating the patient. Combating these diseases is vital as they cause a nuisance to the patients and medical practitioners. Coatings of graphene and its derivatives hold the key to the formation of special surfaces that can rupture microbial cells using their sharp edges, ultimately leading to nuclear and cellular fragmentation. Their incorporation as a whole or as a part in the hospital apparel and the medical device has aided medical practitioners to combat many nosocomial diseases. Graphene is found to be highly virulent with broad-spectrum antimicrobial activity against nosocomial strains and biofilm formation. Their alternate mode of action like trapping and charge transfer has also been discussed well in the present review. The various combinational forms of graphene with its conjugates as a suitable agent to combat nosocomial infections and a potential coating for newer challenges like COVID-19 infections has also been assessed in the current study. Efficiency of graphene sheets has been found to be around 89% with a reaction time as less as 3 h. Polymers with graphene seem to have a higher potency against biofilm formation. When combined with graphene oxide, silver nanoparticles provide 99% activity against nosocomial pathogens. In conclusion, this review would be a guiding light for scientists working with graphene-based coatings to unfold the potentials of this marvelous commodity to tackle the present and future pandemics to come.}, } @article {pmid35841607, year = {2022}, author = {Xie, S and Huang, K and Peng, J and Liu, Y and Cao, W and Zhang, D and Li, X}, title = {Self-Propelling Nanomotors Integrated with Biofilm Microenvironment-Activated NO Release to Accelerate Healing of Bacteria-Infected Diabetic Wounds.}, journal = {Advanced healthcare materials}, volume = {11}, number = {19}, pages = {e2201323}, doi = {10.1002/adhm.202201323}, pmid = {35841607}, issn = {2192-2659}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria ; *Bacterial Infections ; Biofilms ; Collagen ; Cysteine ; *Diabetes Mellitus, Experimental ; *Diabetic Foot/microbiology ; Glutathione ; Mice ; Reactive Nitrogen Species ; Wound Healing ; *Wound Infection/microbiology ; }, abstract = {Diabetic foot ulcer (DFU) treatment is challenged by persistent bacterial infection and hyperglycemia-caused vascular dysplasia. Herein, self-propelled nanomotors are designed to achieve biofilm microenvironment (BME)-activated multistage release of NO for effective sterilization and subsequent angiogenesis promotion. CaO2 nanoparticles (NPs) are capped with PDA layers, followed by complexation with Fe[2+] and surface grafting of cysteine-NO to obtain Janus Ca@PDAFe -CNO NPs. In response to low pH in BME, the decomposition of CaO2 cores generates O2 from one side of Janus NPs to propel biofilm penetration, and the released H2 O2 and Fe[2+] produce •OH through Fenton reaction. The concurrent glutathione-triggered release of NO can be converted into reactive nitrogen species, which exhibit significantly higher bactericidal efficacy than those with only generation of •OH or NO. The slow release of NO for an extended time period promotes endothelial cell proliferation and migration. On Staphylococcus aureus-infected skin wounds of diabetic mice, NP treatment eliminates bacterial infections and significantly elevates blood vessel densities, leading to full wound recovery and regeneration of arranged collagen fibers and skin accessories. Thus, the self-propelling and multistage release of NO provide a feasible strategy to combat biofilm infection without using any antibiotics and accelerate angiogenesis and wound healing for DFU treatment.}, } @article {pmid35840981, year = {2022}, author = {Whitely, ME and Helms, SM and Muire, PJ and Lofgren, AL and Lopez, RA and Wenke, JC}, title = {Preclinical evaluation of a commercially available biofilm disrupting wound lavage for musculoskeletal trauma.}, journal = {Journal of orthopaedic surgery and research}, volume = {17}, number = {1}, pages = {347}, pmid = {35840981}, issn = {1749-799X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria ; Biofilms ; *Fractures, Open/therapy ; Rats ; Staphylococcus aureus ; Therapeutic Irrigation ; Vancomycin/pharmacology ; *Wound Infection/drug therapy ; }, abstract = {BACKGROUND: Treatment of open fractures remains a significant challenge in trauma care as these fractures are accompanied by extensive soft tissue damage, exposing the wound site to contaminants and increasing infection risk. Formation of biofilm, a capsule-like environment that acts as a barrier to treatment, is a primary mode by which infecting pathogens persist at the wound site. Therefore, a pressing need exists to identify irrigation methods that can disrupt biofilm and expose pathogens to treatment. This study aims to evaluate the antibiofilm wound lavage, Bactisure™, in comparison with saline for care of severe musculoskeletal wounds and elucidate potential effects on antibiotic treatment success.

METHODS: UAMS-1 Staphylococcus aureus biofilms were formed in vitro and treated with Bactisure™ wound lavage or sterile normal saline, alone, or in combination with sub-biofilm inhibitory levels of vancomycin. Characterization methods included quantification of biofilm biomass, quantification of viable biofilm bacteria, and biofilm matrix imaging. For in vivo assessment, a delayed treatment model of contaminated open fracture was used wherein a critical-sized defect was created in a rat femur and wound site inoculated with UAMS-1. Following a 6 h delay, wounds were debrided, irrigated with lavage of interest, and antibiotic treatments administered. Bacterial enumeration was performed on bone and hardware samples after two weeks.

RESULTS: An immediate reduction in biofilm biomass was observed in vitro following antibiofilm lavage treatment, with a subsequent 2- to 3- log reduction in viable bacteria achieved after 24 h. Furthermore, biofilms treated with antibiofilm lavage in combination with vancomycin exhibited a minor, but statistically significant, decrease in viable bacteria compared to irrigation alone. In vivo, a minor, not statistically significant, decrease in median bioburden was observed for the antibiofilm lavage compared to saline when used in combination with antibiotics. However, the percentage of bone and hardware samples with detectable bacteria was reduced from 50 to 38%.

CONCLUSIONS: These results suggest that the antibiofilm wound lavage, Bactisure™, may hold promise in mitigating infection in contaminated musculoskeletal wounds and warrants further investigation. Here, we proposed multiple mechanisms in vitro by which this antibiofilm lavage may help mitigate infection, and demonstrate this treatment slightly outperforms saline in controlling bioburden in vivo.}, } @article {pmid35840879, year = {2022}, author = {Cai, Z and Mo, Z and Zheng, S and Lan, S and Xie, S and Lu, J and Tang, C and Shen, Z}, title = {Flavaspidic acid BB combined with mupirocin improves its anti-bacterial and anti-biofilm activities against Staphylococcus epidermidis.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {179}, pmid = {35840879}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Butyrophenones ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Mupirocin/pharmacology ; *Staphylococcus epidermidis ; }, abstract = {BACKGROUND: The increase in drug-resistant opportunistic pathogenic bacteria, especially of antibiotic-resistant Staphylococcus epidermidis (S. epidermidis), has led to difficulties in the treatment of skin and soft tissue infections (SSTI). The major reason for bacterial resistance is the formation of bacterial biofilm. Here, we report a promising combination therapy of flavaspidic acid BB (BB) and mupirocin, which can effectively eradicate the biofilm of S. epidermidis and eliminate its drug resistance.

RESULT: The susceptibility test showed that the combination of BB and mupirocin has good antibacterial and antibiofilm activities, and the fractional inhibitory concentration index (FICI) of BB combined with mupirocin was 0.51 ± 0.00 ~ 0.75 ± 0.05, showing synergistic effect. Moreover, the time-kill curve assay results indicated that the combination of drugs can effectively inhibit the planktonic S. epidermidis. After drugs treatment, the drug-combination showed significantly inhibitory effects on the metabolic activity and total biomass in each stage of biofilm formation. The synergistic effect is likely related to the adhesion between bacteria, which is confirmed by field emission scanning electron microscope. And the expression level of aap, sarA and agrA genes were detected by real-time quantitative PCR (qRT-PCR).

CONCLUSION: Our study provides the experimental data for the use of BB for the clinical treatment of skin infections and further demonstrate the potential of BB as a novel biofilm inhibitor.}, } @article {pmid35839697, year = {2022}, author = {Leerahakan, P and Matangkasombut, O and Tarapan, S and Lam-Ubol, A}, title = {Biofilm formation of Candida isolates from xerostomic post-radiotherapy head and neck cancer patients.}, journal = {Archives of oral biology}, volume = {142}, number = {}, pages = {105495}, doi = {10.1016/j.archoralbio.2022.105495}, pmid = {35839697}, issn = {1879-1506}, mesh = {Biofilms ; Candida ; Candida albicans ; Candida tropicalis ; *Candidiasis, Oral/complications ; *Head and Neck Neoplasms/complications/radiotherapy ; Humans ; *Xerostomia/etiology ; }, abstract = {UNLABELLED: Oral candidiasis is a common problem in post-radiation head and neck cancer (HNC) patients. While biofilm formation is a crucial virulence factor for Candida colonization, existing information on biofilm formation capability of Candida in cancer patients is scarce.

OBJECTIVE: To evaluate biofilm formation capability of Candida spp. colonized in xerostomic post-radiotherapy HNC patients.

DESIGN: Candida albicans and non-albicans Candida species were previously isolated from xerostomic post-radiation cancer patients and healthy individuals. Biofilm mass and biofilm metabolic activity were investigated by crystal violet and MTT assays, respectively. Their relationship with clinical parameters was analyzed using Mann-Whitney U and Chi-square tests.

RESULTS: A total of 109 and 45 Candida isolates from 64 cancer patients and 34 controls, respectively, were evaluated. Both biofilm mass and metabolic activity of Candida isolates from cancer patients were higher than those from controls. The between-group differences were statistically significant in C. albicans (p < 0.001) for biofilm mass, and in C. tropicalis (p = 0.01) for biofilm metabolic activity. Overall, C. tropicalis was the best biofilm producers in both groups. Additionally, we found that higher biofilm formation among C. albicans was associated with low saliva buffering capacity.

CONCLUSIONS: C. albicans and C. tropicalis isolated from xerostomic post-radiation cancer patients had higher biofilm formation capability than those from healthy individuals. Our findings suggest that, in addition to compromised host factors, higher biofilm formation capability may also contribute to the pathogenesis of oral candidiasis in HNC patients. This novel information potentially adds to proper management for these patients.}, } @article {pmid35837847, year = {2022}, author = {Shi, L and Cai, Y and Gao, S and Fang, D and Lu, Y and Li, P and Wu, QL}, title = {Gene expression in the microbial consortia of colonial Microcystis aeruginosa-a potential buoyant particulate biofilm.}, journal = {Environmental microbiology}, volume = {24}, number = {10}, pages = {4931-4945}, doi = {10.1111/1462-2920.16133}, pmid = {35837847}, issn = {1462-2920}, mesh = {Alginates/metabolism ; Arginine/metabolism ; Biofilms ; DNA, Ribosomal ; Gene Expression ; Lakes/microbiology ; Methionine/genetics/metabolism ; Microbial Consortia ; *Microcystis/metabolism ; Peptidoglycan/metabolism ; }, abstract = {Microcystis spp., notorious bloom-forming cyanobacteria, are often present in colony form in eutrophic lakes worldwide. Uncovering the mechanisms underlying Microcystis colony formation and maintenance is vital to controlling the blooms, but it has long been a challenge. Here, bacterial communities and gene expression patterns of colonial and unicellular forms of one non-axenic strain of Microcystis aeruginosa isolated from Lake Taihu were compared. Evidently, different microbial communities between them were observed through 16S rDNA MiSeq sequencing. Metatranscriptome analyses revealed that transcripts for pathways involved in bacterial biofilm formation, such as biosynthesis of peptidoglycan and arginine by Bacteroidetes, methionine biosynthesis, alginate metabolism, flagellum, and motility, as well as widespread colonization islands by Proteobacteria, were highly enriched in the colonial form. Furthermore, transcripts for nitrogen fixation and denitrification pathways by Proteobacteria that usually occur in biofilms were significantly enriched in the colonial Microcystis. Results revealed that microbes associated with Microcystis colonies play important roles through regulation of biofilm-related genes in colony formation and maintenance. Moreover, Microcystis colony represents a potential 'buoyant particulate biofilm', which is a good model for biofilm studies. The biofilm features of colonial Microcystis throw a new light on management and control of the ubiquitous blooms in eutrophic waters.}, } @article {pmid35837838, year = {2022}, author = {Yuan, S and Guo, S and Huang, X and Meng, F}, title = {Time-lagged interspecies interactions prevail during biofilm development in moving bed biofilm reactor.}, journal = {Biotechnology and bioengineering}, volume = {119}, number = {10}, pages = {2770-2783}, doi = {10.1002/bit.28177}, pmid = {35837838}, issn = {1097-0290}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; *Bioreactors ; Phylogeny ; Waste Disposal, Fluid ; }, abstract = {Clarifying the essential succession dynamics of interspecies interactions during biofilm development is crucial for the regulation and application of biofilm-based processes. In this study, regular and time-series phylogenetic molecular ecological networks were constructed to investigate ordinary and time-lagged interspecies interactions during biofilm development in a moving bed biofilm reactor. Positive interactions dominated both regular (89.78%) and time-series (77.04%) ecological networks, suggesting that extensive cooperative behaviors facilitated biofilm development. The pronounced directional interactions (72.52%) in the time-series network further indicated that time-lagged interspecies interactions prevailed in the biofilm development process. Specifically, the proportion of directional negative interactions was higher than that of positive interactions, implying that interspecific competition preferred to be time-lagged. The time-series network revealed that module hubs exhibited extensive time-lagged positive interactions with their neighbors, and most of them exhibited altruistic behaviors. Keystone species possessing more positive interactions were positively correlated with biofilm biomass, NO3 [-] -N concentrations, and the removal efficiencies of NH4 [+] -N and chemical oxygen demand. However, keystone species and peripherals that were negatively targeted by their neighbors showed positive correlations with the concentrations of NO2 [-] -N, polysaccharides, and proteins in the soluble microbial products. The data highlight that the time-series network can provide directional microbial interactions along with the biofilm development process, which would help to predict the tendency of community shifts and propose efficient strategies for the regulation of biofilm-based processes.}, } @article {pmid35836267, year = {2022}, author = {Tang, S and Zhang, H and Mei, L and Dou, K and Jiang, Y and Sun, Z and Wang, S and Hasanin, MS and Deng, J and Zhou, Q}, title = {Fucoidan-derived carbon dots against Enterococcus faecalis biofilm and infected dentinal tubules for the treatment of persistent endodontic infections.}, journal = {Journal of nanobiotechnology}, volume = {20}, number = {1}, pages = {321}, pmid = {35836267}, issn = {1477-3155}, support = {31900957//National Natural Science Foundation of China/ ; ZR2019QC007//Natural Science Foundation of Shandong Province/ ; 2019KJE015//Innovation and technology program for the excellent youth scholars of higher education of Shandong province/ ; 2021Q069//Traditional Chinese Medicine Science and Technology Project of Shandong province/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Carbon ; *Enterococcus faecalis ; Polysaccharides ; *Root Canal Irrigants/pharmacology/therapeutic use ; Sodium Hypochlorite/pharmacology/therapeutic use ; }, abstract = {Enterococcus faecalis (E. faecalis) biofilm-associated persistent endodontic infections (PEIs) are one of the most common tooth lesions, causing chronic periapical periodontitis, root resorption, and even tooth loss. Clinical root canal disinfectants have the risk of damaging soft tissues (e.g., mucosa and tongue) and teeth in the oral cavity, unsatisfactory to the therapy of PEIs. Nanomaterials with remarkable antibacterial properties and good biocompatibility have been developed as a promising strategy for removing pathogenic bacteria and related biofilm. Herein, carbon dots (CDs) derived from fucoidan (FD) are prepared through a one-pot hydrothermal method for the treatment of PEIs. The prepared FDCDs (7.15 nm) with sulfate groups and fluorescence property are well dispersed and stable in water. Further, it is found that in vitro FDCDs display excellent inhibiting effects on E. faecalis and its biofilm by inducing the formation of intracellular and extracellular reactive oxygen species and altering bacterial permeability. Importantly, the FDCDs penetrated the root canals and dentinal tubules, removing located E. faecalis biofilm. Moreover, the cellular assays show that the developed FDCDs have satisfactory cytocompatibility and promote macrophage recruitment. Thus, the developed FDCDs hold great potential for the management of PEIs.}, } @article {pmid35835418, year = {2022}, author = {Ni, M and Pan, Y and Li, D and Huang, Y and Chen, Z and Li, L and Song, Z and Zhao, Y}, title = {Metagenomics reveals the metabolism of polyphosphate-accumulating organisms in biofilm sequencing batch reactor: A new model.}, journal = {Bioresource technology}, volume = {360}, number = {}, pages = {127603}, doi = {10.1016/j.biortech.2022.127603}, pmid = {35835418}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Metagenomics ; Phosphorus/metabolism ; *Polyphosphates/metabolism ; }, abstract = {This study assessed the impact of the operating conditions of the biofilm sequencing batch reactor (BSBR) on the community structure and the growth/metabolic pathways of its polyphosphate-accumulating organisms (PAOs). There are significant difference with reference to the enhanced biological phosphorus removal (EBPR) process. The leading PAOs in BSBR generally are capable of high affinity acetate metabolism, gluconeogenesis, and low affinity phosphate transport, and have various carbon source supplementation pathways to ensure the efficient circulation of energy and reducing power. A new model of the metabolic mechanism of PAOs in the BSBR was formulated, which features low glycogen metabolism with simultaneous gluconeogenesis and glycogenolysis and differs significantly from the classic mechanism based on Candidatus_Accumulibacter and Tetrasphaera. The findings will assist the efficient recovery of low concentration phosphate in municipal wastewater.}, } @article {pmid35834031, year = {2022}, author = {Karimi, E and Aliasgharzad, N and Esfandiari, E and Hassanpouraghdam, MB and Neu, TR and Buscot, F and Reitz, T and Breitkreuz, C and Tarkka, MT}, title = {Biofilm forming rhizobacteria affect the physiological and biochemical responses of wheat to drought.}, journal = {AMB Express}, volume = {12}, number = {1}, pages = {93}, pmid = {35834031}, issn = {2191-0855}, abstract = {Plant growth promoting rhizobacteria (PGPR) can attenuate the adverse effects of water deficit on plant growth. Since drought stress tolerance of bacteria has earlier been associated to biofilm formation, we aimed to investigate the role of bacterial biofilm formation in their PGPR activity upon drought stress. To this end, a biofilm-forming bacterial collection was isolated from the rhizospheres of native arid grassland plants, and characterized by their drought tolerance and evaluated on their plant growth promoting properties. Most bacterial strains formed biofilm in vitro. Most isolates were drought tolerant, produced auxins, showed 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and solubilized mineral phosphate and potassium, but at considerably different levels. Greenhouse experiments with the most promising isolates, B1, B2 and B3, under three levels of water deficit and two wheat varieties led to an increased relative water content and increased harvest index at both moderate and severe water deficit. However, the bacteria did not affect these plant parameters upon regular watering. In addition, decreased hydrogen peroxide levels and increased glutathione S-transferase activity occurred under water deficit. Based on these results, we conclude that by improving root traits and antioxidant defensive system of wheat, arid grassland rhizospheric biofilm forming bacilli may promote plant growth under water scarcity.}, } @article {pmid35834022, year = {2022}, author = {Temel, A and Erac, B}, title = {Investigating Biofilm Formation and Antibiofilm Activity Using Real Time Cell Analysis Method in Carbapenem Resistant Acinetobacter baumannii Strains.}, journal = {Current microbiology}, volume = {79}, number = {9}, pages = {256}, pmid = {35834022}, issn = {1432-0991}, mesh = {*Acinetobacter Infections/microbiology ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Carbapenems/pharmacology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Acinetobacter baumannii is a significant nosocomial pathogen, with its biofilm forming capacity playing an important role in its pathogenicity. The fast and reliable detection of the biofilm formation and measurement of antibiofilm activity of various molecules are critical for combating A. baumannii infections. In this study, we aimed to detect biofilm formation by real time cell analyses (RTCA) method in clinical A. baumannii isolates and to investigate antibiofilm activities of tigecycline (TGC), N-acetylcysteine (NAC), and acetylsalicylic acid (ASA). The effect of the tested drugs on expressions of biofilm-related genes bap and csuE in clinical A. baumannii strains was also analyzed by real time quantitative reverse transcription polymerase chain reaction (RT-qPCR). Biofilm forming capacities for strong and weak biofilm producer A. baumannii strains were detected within 10 h by RTCA method (P < 0.05). We also observed that sub-minimum inhibitory concentrations of NAC + TGC and ASA + TGC combinations could significantly reduce biofilm formation and expression of biofilm-related genes in A. baumanii strains. No statistically significant activity of the tested drugs was detected against mature biofilms of the bacterial strains with the RTCA method. These results suggest that reproducible results on biofilm production capacity of A. baumannii strains and antibiofilm activities of various compounds can be obtained in a short time using RTCA method. Therefore, RTCA method seems to be a beneficial technique for biofilm detection and can help in combating A. baumannii infections by giving health providers the opportunity of implementing antibiofilm treatment strategies in a timely manner.}, } @article {pmid35832038, year = {2022}, author = {Panebianco, F and Rubiola, S and Chiesa, F and Civera, T and Di Ciccio, PA}, title = {Effect of gaseous ozone treatment on biofilm of dairy-isolated Pseudomonas spp. strains.}, journal = {Italian journal of food safety}, volume = {11}, number = {2}, pages = {10350}, pmid = {35832038}, issn = {2239-7132}, abstract = {Microbial biofilms existing in food industries have been implicated as important contamination sources of spoilage and pathogenic microorganisms in the finished products. Among the innovative strategies proposed to contrast biofilms in food environments, ozone is recognised as an environmentally friendly technology but there are few studies about its effect against bacterial biofilms. The objective of this study was to evaluate the effect of gaseous ozone (50 ppm for 6 h) in inhibition and eradication of biofilm formed by twenty-one dairyisolated Pseudomonas spp. strains. Before ozone treatments, all isolates were screened for biofilm formation according to a previously described method. Strains were then divided in four groups: weak, weak/moderate, moderate/strong, and strong biofilm producers based on the biofilm biomass value of each isolate determined using the optical density (OD - 595 nm). Inhibition treatment was effective on the strain (C1) belonging to the weak producers' group, on all strains classified as weak/moderate producers, on two strains (C8 and C12) belonging to the group of moderate/strong producers and on one strain (C13) classified as strong producer. Conversely, eradication treatments were ineffective on all strains tested, except for the strain C4 which reduced its biofilm-forming abilities after exposure to ozone gas. In conclusion, gaseous ozone may be used to enhance existing sanitation protocols in food processing environments, but its application alone not seems sufficient to contrast Pseudomonas spp. established biofilms.}, } @article {pmid35830909, year = {2022}, author = {Sathishkumar, K and Kannan, VR and Alsalhi, MS and Rajasekar, A and Devanesan, S and Narenkumar, J and Kim, W and Liu, X}, title = {Intimately coupled gC3N4 photocatalysis and mixed culture biofilm enhanced detoxification of sulfamethoxazole: Elucidating degradation mechanism and toxicity assessment.}, journal = {Environmental research}, volume = {214}, number = {Pt 1}, pages = {113824}, doi = {10.1016/j.envres.2022.113824}, pmid = {35830909}, issn = {1096-0953}, mesh = {Anti-Bacterial Agents ; Bacteria ; Biodegradation, Environmental ; Biofilms ; *Sulfamethoxazole ; *Titanium ; }, abstract = {In recent years, wide spread of antibiotic-resistant microorganisms and genes emerging globally, an eco-friendly method for efficient degradation of antibiotics from the polluted environment is essential. Intimately coupled photocatalysis and biodegradation (ICPB) using gC3N4 for enhanced degradation of sulfamethoxazole (SMX) was investigated. The gC3N4 were prepared and coated on the carbon felt. The mixed culture biofilm was developed on the surface as a biocarrier. The photocatalytic degradation showed 74%, and ICPB exhibited 95% SMX degradation efficiency. ICPB showed superior visible light adsorption, photocatalytic activity, and reduced charge recombination. The electron paramagnetic resonance spectrum confirms that the generation of •OH and O2• radicals actively participated in the degradation of SMX into biodegradable intermediated compounds, and then, the bacterial communities present in the biofilm mineralized the biodegradable compound into carbon dioxide and water. Moreover, the addition of NO3[-], PO4[-,] and Cl[-] significantly enhanced the degradation efficiency by trapping the surface electron. Stability experiments confirmed that gC3N4 biohybrid can maintain 85% SMX degradation efficiency after 5 consecutive recycling. Extracellular polymeric substances characterization results show that biohybrid contains 47 mg/L, 14 mg/L, and 13 mg/L protein, carbohydrate, and humic acid, respectively, which can protect the bacterial communities from the antibiotic toxicity and reactive oxygen species. Furthermore, biotoxicity was investigated using degradation products on E.coli and results revealed 83% detoxification efficiency. Overall, this study suggested that gC3N4 photocatalyst in an ICPB can be used as a promising eco-friendly method to degrade sulfamethoxazole efficiently.}, } @article {pmid35830082, year = {2022}, author = {Barros, ILE and Veiga, FF and Jarros, IC and Corrêa, JL and Santos, RSD and Bruschi, ML and Negri, M and Svidzinski, TIE}, title = {Promising effect of propolis and a by-product on planktonic cells and biofilm formation by the main agents of human fungal infections.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {94}, number = {2}, pages = {e20210189}, doi = {10.1590/0001-3765202220210189}, pmid = {35830082}, issn = {1678-2690}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; Humans ; Microbial Sensitivity Tests ; *Mycoses ; Plankton ; Plant Extracts/pharmacology ; *Propolis/pharmacology ; }, abstract = {Few antifungals available today are effective in treating biofilms. Thus, it is urgent to discover new compounds, such as natural products, that provide improvements to existing treatments or the development of new antifungal therapies. This study aimed to perform a comparative analysis between the green propolis extract (PE) and its by-product, a waste of propolis extract (WPE) through a screening with Candida sp., Fusarium sp. and Trichophyton sp. The antifungal property of PE and WPE was assessed by the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determination in planktonic cells. The influence of both extracts on the inhibition of biofilm formation in these fungi was also tested. The WPE MIC and MFC values (68.75 to 275.0 µg/mL) were three to twelve times lower than the values obtained for PE (214.06 to 1712.5 µg/mL). PE was more efficient than WPE in inhibiting the biofilm initial phase, especially in C. albicans. Meanwhile, WPE had dose-dependent behavior for the three fungi, being more effective on filamentous ones. Both PE and WPE showed excellent antifungal activity on planktonic cells and demonstrated great efficacy for inhibiting biofilm formation in the three fungi evaluated.}, } @article {pmid35829973, year = {2022}, author = {Purohit, D and Gajjar, D}, title = {Tec1 and Ste12 transcription factors play a role in adaptation to low pH stress and biofilm formation in the human opportunistic fungal pathogen Candida glabrata.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {4}, pages = {789-802}, pmid = {35829973}, issn = {1618-1905}, support = {BT/PR8100/MED/29/707/2013.//Department of Biotechnology, Ministry of Science and Technology, Government of India,/ ; }, mesh = {Biofilms ; Candida glabrata/genetics/metabolism ; DNA/metabolism ; DNA-Binding Proteins ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal ; Humans ; Hydrogen-Ion Concentration ; Mitogen-Activated Protein Kinases/genetics/metabolism ; Pheromones/metabolism ; RNA, Messenger/metabolism ; Saccharomyces cerevisiae/metabolism ; *Saccharomyces cerevisiae Proteins ; *Transcription Factors/genetics ; }, abstract = {Eukaryotic cells respond to environmental cues through mitogen activated protein kinase (MAPK) signaling pathways. Each MAPK cascade is specific to particular stimuli and mediates specialized responses through activation of transcription factors. In the budding yeast, Saccharomyces cerevisiae, the pheromone-induced mating pathway and the starvation-responsive invasive growth/filamentation pathway generate their distinct outputs through the transcription factors Ste12 and Tec1, respectively. In this study, we report the functional characterization of these transcription factors in the closely related human opportunistic pathogenic yeast Candida glabrata. Two homologues each for S. cerevisiae TEC1 and STE12 were identified in C. glabrata. Both C. glabrata Tec1 proteins contain the N-terminal TEA DNA-binding domain characteristic of the TEA/ATTS transcription factor family. Similarly, the DNA-binding homeodomain shared by members of the highly conserved fungal Ste12 transcription factor family is present in N-terminus of both C. glabrata Ste12 transcription factors. We show that both C. glabrata STE12 genes are at least partial functional orthologues of S. cerevisiae STE12 as they can rescue the mating defect of haploid S. cerevisiae ste12 null mutant. Knockout of one of the STE12 genes (ORF CAGL0H02145g) leads to decreased biofilm development; a stronger biofilm-impaired phenotype results from loss of both CgSTE12 genes in the double deletion mutant (Cgste12ΔΔ). The transcript levels of one of the TEC1 genes (ORF CAGL0M01716g) were found to be upregulated upon exposure to low pH; its deletion causes slightly increased sensitivity to higher concentrations of acetic acid. Heat shock leads to increase in mRNA levels of one of the STE12 genes (ORF CAGL0M01254g). These findings suggest a role of Tec1 and Ste12 transcription factors in the regulation of some traits (biofilm formation, response to low pH stress and elevated temperature) that contribute to C. glabrata's ability to colonize various host niches and to occasionally cause disease.}, } @article {pmid35829902, year = {2022}, author = {Mukherjee, S and Bhattacharjee, S and Paul, S and Nath, S and Paul, S}, title = {Biofilm-a Syntrophic Consortia of Microbial Cells: Boon or Bane?.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35829902}, issn = {1559-0291}, abstract = {Biofilm is the conglomeration of microbial cells which is associated with a surface. In the recent times, the study of biofilm has gained popularity and vivid research is being done to know about the effects of biofilm and that it consists of many organisms which are symbiotic in nature, some of which are human pathogens. Here, in this study, we have discussed about biofilms, its formation, relevance of its presence in the biosphere, and the possible remediations to cope up with its negative effects. Since removal of biofilm is difficult, emphasis has been made to suggest ways to prevent biofilm formation and also to devise ways to utilize biofilm in an economically and environment-friendly method.}, } @article {pmid35822790, year = {2022}, author = {Eskova, AI and Andryukov, BG and Yakovlev, AA and Kim, AV and Ponomareva, AL and Obuhova, VS}, title = {Horizontal Transfer of Virulence Factors by Pathogenic Enterobacteria to Marine Saprotrophic Bacteria during Co-Cultivation in Biofilm.}, journal = {Biotech (Basel (Switzerland))}, volume = {11}, number = {2}, pages = {}, pmid = {35822790}, issn = {2673-6284}, abstract = {Environmental problems associated with marine pollution and climate warming create favorable conditions for the penetration and survival of pathogenic bacteria in marine ecosystems. These microorganisms have interspecific competitive interactions with marine bacteria. Co-culture, as an important research strategy that mimics the natural environment of bacteria, can activate silent genes or clusters through interspecies interactions. The authors used modern biotechnology of co-cultivation to dynamically study intercellular interactions between different taxa of bacteria-pathogenic enterobacteria Yersinia pseudotuberculosis and Listeria monocytogenes and saprotrophic marine bacteria Bacillus sp. and Pseudomonas japonica isolated in summer from the coastal waters of the recreational areas of the Sea of Japan. The results of the experiments showed that during the formation of polycultural biofilms, horizontal transfer of genes encoding some pathogenicity factors from Y. pseudotuberculosis and L. monocytogenes to marine saprotrophic bacteria with different secretion systems is possible. It was previously thought that this was largely prevented by the type VI secretion system (T6SS) found in marine saprotrophic bacteria. The authors showed for the first time the ability of marine bacteria Bacillus sp. and P. japonica to biofilm formation with pathogenic enterobacteria Y. pseudotuberculosis and L. monocytogenes, saprophytic bacteria with type III secretion system (T3SS). For the first time, a marine saprotrophic strain of Bacillus sp. Revealed manifestations of hyaluronidase, proteolytic and hemolytic activity after cultivation in a polycultural biofilm with listeria. Saprotrophic marine bacteria that have acquired virulence factors from pathogenic enterobacteria, including antibiotic resistance genes, could potentially play a role in altering the biological properties of other members of the marine microbial community. In addition, given the possible interdomain nature of intercellular gene translocation, acquired virulence factors can be transferred to marine unicellular and multicellular eukaryotes. The results obtained contribute to the paradigm of the epidemiological significance and potential danger of anthropogenic pollution of marine ecosystems, which creates serious problems for public health and the development of marine culture as an important area of economic activity in coastal regions.}, } @article {pmid35820580, year = {2022}, author = {Kumar, S and Paliya, BS and Singh, BN}, title = {Superior inhibition of virulence and biofilm formation of Pseudomonas aeruginosa PAO1 by phyto-synthesized silver nanoparticles through anti-quorum sensing activity.}, journal = {Microbial pathogenesis}, volume = {170}, number = {}, pages = {105678}, doi = {10.1016/j.micpath.2022.105678}, pmid = {35820580}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Biofilms ; *Metal Nanoparticles/chemistry ; *Pseudomonas aeruginosa ; Silver/pharmacology ; Virulence/genetics ; Virulence Factors/metabolism ; }, abstract = {Quorum sensing (QS)-regulated bacterial biofilm formation is a crucial issue in causing resistance against existing antibiotics. There is a considerable necessity to disrupt the interrelationship between bacterial QS, virulence, and biofilm formation. Disabling QS could be a novel tactic of great clinical importance. Here, we biosynthesized silver nanoparticles (Ka-AgNPs) using the aqueous leaf extract of Koelreuteria paniculata as a reducing and capping agents. The UV-Vis spectroscopy confirmed the synthesis of Ka-AgNPs as a characterization peak observed at 420 nm. TEM image revealed the spherical shape distribution of Ka-AgNPs with average particle size of 30.0 ± 5 nm. The anti-QS activity of Ka-AgNPs was tested against a bio-indicator bacterium Chromobacterium violaceum 12472 and a multi-drug resistant model strain of Pseudomonas aeruginosa (PAO1). The results demonstrated that the Ka-AgNPs superiorly inhibited QS-regulated virulence factors in PAO1 without affecting cell viability compared to chemically synthesized AgNPs (Cs-AgNPs). The Ka-AgNPs effectively suppressed the formation of biofilm of PAO1. RT-PCR results revealed that the Ka-AgNPs inhibited the expression of QS-regulated virulence genes of PAO1. These results suggest that the phyto-synthesized AgNPs could be used as promising anti-infective agents for treating drug-resistant P. aeruginosa.}, } @article {pmid35818907, year = {2022}, author = {Mekky, AEM and El-Idreesy, TT and Sanad, SMH}, title = {Chloramine Trihydrate-Mediated Tandem Synthesis of New Pyrrole and/or Arene-Linked Mono- and Bis(1,3,4-Oxadiazole) Hybrids as Potential Bacterial Biofilm and MRSA Inhibitors.}, journal = {Chemistry & biodiversity}, volume = {19}, number = {8}, pages = {e202200338}, doi = {10.1002/cbdv.202200338}, pmid = {35818907}, issn = {1612-1880}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Chloramines/pharmacology ; Escherichia coli ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Oxadiazoles/pharmacology ; Pseudomonas aeruginosa ; Pyrroles/pharmacology ; Staphylococcus aureus ; }, abstract = {A two-step tandem protocol was used to prepare new pyrrole and/or arene-linked bis(1,3,4-oxadiazoles) as well as their mono-analogs. The appropriate aldehydes and benzohydrazides were first condensed in ethanol at 80 °C to yield the corresponding N-benzoylhydrazones. Without isolation, the previous intermediates were subjected to a chloramine trihydrate-mediated oxidative cyclization in DMSO at 180 °C to yield the target molecules. The antibacterial potency of the (pyrrole-arene)-linked hybrids exceeded the arene-linked hybrids, and the bis(1,3,4-oxadiazoles) exceeded their mono-analogs against six different ATCC strains. Furthermore, the antibacterial efficacy of bis(1,3,4-oxadiazoles) 11c, and 11f, which are linked to pyrrole, and (p-tolylthio)methyl units, was highest against S. aureus, E. coli, and P. aeruginosa strains. Their MIC ranged between 3.8 and 3.9 μM, while their MBC values ranged between 7.7 and 15.8 μM. Additionally, they showed promising bacterial biofilm inhibitory activity against the same strains tested, with IC50 values ranging from 4.7 to 5.3 μM. They were also effective against MRSA ATCC : 33591, and ATCC : 43300 strains, with MIC, and MBC values ranging from 3.8-7.9 and 7.7-15.8 μM, respectively. When tested against the MCF-10A cell lines, hybrids 11c, and 11f are cytotoxic at concEntrations that are more than 6 and 13-fold higher than their MIC values against the S. aureus, E. coli, and P. aeruginosa strains, respectively. This lends support to both hybrids' potential as safe antibacterial agents.}, } @article {pmid35818769, year = {2022}, author = {Yamabe, K and Arakawa, Y and Shoji, M and Miyamoto, K and Tsuchiya, T and Minoura, K and Akeda, Y and Tomono, K and Onda, M}, title = {Enhancement of Acinetobacter baumannii biofilm growth by cephem antibiotics via enrichment of protein and extracellular DNA in the biofilm matrices.}, journal = {Journal of applied microbiology}, volume = {133}, number = {3}, pages = {2002-2013}, pmid = {35818769}, issn = {1365-2672}, mesh = {*Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Carbapenems/pharmacology ; Ceftazidime/pharmacology ; Ceftriaxone/pharmacology ; DNA ; Extracellular Polymeric Substance Matrix ; }, abstract = {AIMS: The aims were to determine the effects of subinhibitory concentrations of eight cephem and carbapenem antibiotics on the biofilm formation of Acinetobacter baumannii cells and examine their effects on pre-established biofilms.

METHODS AND RESULTS: Effects of antibiotics on biofilm formation were assayed using microtitre plates with polystyrene peg-lids. Cefmetazole, ceftriaxone, ceftazidime and cefpirome increased the biomass of pre-established biofilms on pegs in the range of their sub-minimum inhibitory concentrations (MICs), whereas none increased biofilm formation by planktonic cells. Carbapenems had a negative effect. The constituents of antibiotic-induced biofilms were analysed. Ceftriaxone or ceftazidime treatment markedly increased the matrix constituent amounts in the biofilms (carbohydrate, 2.7-fold; protein, 8.9-12.7-fold; lipid, 3.3-3.6-fold; DNA, 9.1-12.2-fold; outer membrane vesicles, 2.7-3.8-fold and viable cells, 6.8-10.1-fold). The antibiotic-enhanced biofilms had increased outer membrane protein A and were resistant to the anti-biofilm effect of azithromycin.

CONCLUSIONS: Some cephems increased the biomass of pre-established biofilms in the ranges of their sub-MICs. The antibiotic-enhanced biofilms possessed more virulent characteristics than normal biofilms.

Incomplete administration of certain cephems following biofilm-related Ac. baumannii infections could adversely cause exacerbated and chronic clinical results.}, } @article {pmid35818281, year = {2022}, author = {Lupi, L and Paggetti, H and Bertrand, MF and Charavet, C}, title = {[Biofilm and Orthodontic Materials: literature reviews and Scanning Electron Microscopy (SEM) images gallery].}, journal = {L' Orthodontie francaise}, volume = {93}, number = {2}, pages = {111-123}, doi = {10.1684/orthodfr.2022.74}, pmid = {35818281}, issn = {1954-3395}, mesh = {Biofilms ; Dental Alloys ; *Dental Plaque ; Elastomers ; Humans ; Microscopy, Electron, Scanning ; Orthodontic Appliance Design ; *Orthodontic Brackets ; Orthodontic Wires ; Stainless Steel ; }, abstract = {INTRODUCTION: Plaque control remains a concern in oral health but also in orthodontics.

OBJECTIVE: The aim of this paper was to investigate the dental plaque adhesion to different orthodontic appliances.

MATERIALS AND METHODS: Four literature reviews were initiated to clarify the accumulation of dental plaque to different orthodontic appliances, namely the type of brackets (conventional versus self-ligating, metal versus clear), the type of ligatures (metal versus elastomeric) in addition to the type of archwires. Moreover, a gallery of Scanning Electron Microscopy (SEM) images was made on different orthodontic appliances before and/or after time in the oral cavity.

RESULTS: Considering the strong methodological heterogeneity of the included studies, there is no consensus on which type of bracket should be preferred for the prevention of plaque retention. Metal ligatures would be less prone to plaque accumulation compared to elastomeric ligatures, which are themselves color-dependent. The type of archwire was not investigated in this topic. SEM images highlighted the presence of anfractuosities on the surface of new orthodontic archwires as well as the presence of biofilm at different degrees of maturation on the appliances after time in the oral cavity.

CONCLUSION: Although it is not possible to establish a consensus on which orthodontic appliances should be preferred to decrease plaque retention, different stages of biofilm evolution are observable on their surface and therefore potentially associated with a proportional virulence.}, } @article {pmid35817179, year = {2022}, author = {Liu, Y and Xi, Y and Xie, T and Liu, H and Su, Z and Huang, Y and Xu, W and Wang, D and Zhang, C and Li, X}, title = {Enhanced removal of diclofenac via coupling Pd catalytic and microbial processes in a H2-based membrane biofilm reactor: Performance, mechanism and biofilm microbial ecology.}, journal = {Chemosphere}, volume = {307}, number = {Pt 1}, pages = {135597}, doi = {10.1016/j.chemosphere.2022.135597}, pmid = {35817179}, issn = {1879-1298}, mesh = {Biofilms ; *Bioreactors ; Catalysis ; *Diclofenac ; Humans ; Membranes ; }, abstract = {Diclofenac (DCF) is a most widely used anti-inflammatory drug, which has attracted worldwide attention given its low biodegradability and ecological damage, especially toxic effects on mammals including humans. In this study, a H2-based membrane biofilm reactor (H2-MBfR) was constructed with well-dispersed Pd nanoparticles generated in situ. The Pd-MBfR was applied for catalytic reductive dechlorination of DCF. In batch tests, DCF concentration had significantly effect on the rate and extent DCF removal, and NO3[-] had negative impact on DCF reductive dechlorination. Over 67% removal of 0.5 mg/L DCF and 99% removal of 10 mg/L NO3[-]-N were achieved in 90 min, and the highest removal of 97% was obtained at 0.5 mg/L DCF in the absence of NO3[-]. Over 78 days of continuous operation, the highest steady-state removal flux of DCF was 0.0097 g/m[2]/d. LC-MS analysis indicated that the major product was 2-anilinephenylacetic acid (APA). Dechlorination was the main removal process of DCF mainly owing to the catalytic reduction by PdNPs, microbial reduction, and the synergistic reduction of microbial and PdNPs catalysis using direct delivery of H2. Moreover, DCF reductive Dechlorination shifted the microbial community in the biofilms and Sporomusa was responsible for DCF degradation. In summary, this work expands a remarkable feasibility of sustainable catalytic removal of DCF.}, } @article {pmid35816421, year = {2022}, author = {Lee, SW and Johnson, EL and Chediak, JA and Shin, H and Wang, Y and Phillips, KS and Ren, D}, title = {High-Throughput Biofilm Assay to Investigate Bacterial Interactions with Surface Topographies.}, journal = {ACS applied bio materials}, volume = {5}, number = {8}, pages = {3816-3825}, pmid = {35816421}, issn = {2576-6422}, support = {R01 EB030621/EB/NIBIB NIH HHS/United States ; }, mesh = {Bacteria ; Biocompatible Materials ; Biofilms ; *Breast Implants/adverse effects ; Humans ; *Lymphoma, Large-Cell, Anaplastic/etiology ; }, abstract = {The specific topography of biomaterials plays an important role in their biological interactions with cells and thus the safety of medical implants. Antifouling materials can be engineered with topographic features to repel microbes. Meanwhile, undesired topographies of implants can cause complications such as breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). While the cause of BIA-ALCL is not well understood, it is speculated that textured surfaces are prone to bacterial biofilm formation as a contributing factor. To guide the design of safer biomaterials and implants, quantitative screening approaches are needed to assess bacterial adhesion to different topographic surface features. Here we report the development of a high-throughput microplate biofilm assay for such screening. The assay was used to test a library of polydimethylsiloxane (PDMS) textures composed of varying sizes of recessive features and distances between features including those in the range of breast implant textures. Outliers of patterns prone to bacterial adhesion were further studied using real-time confocal fluorescence microscopy. The results from these analyses revealed that surface area itself is a poor predictor for adhesion, while the size and spacing of topographic features play an important role. This high-throughput biofilm assay can be applied to studying bacteria-material interactions and rational development of materials that inhibit bacterial colonization.}, } @article {pmid35816289, year = {2022}, author = {de Avila, ED and Nagay, BE and Pereira, MMA and Barão, VAR and Pavarina, AC and van den Beucken, JJJP}, title = {Race for Applicable Antimicrobial Dental Implant Surfaces to Fight Biofilm-Related Disease: Advancing in Laboratorial Studies vs Stagnation in Clinical Application.}, journal = {ACS biomaterials science & engineering}, volume = {8}, number = {8}, pages = {3187-3198}, doi = {10.1021/acsbiomaterials.2c00160}, pmid = {35816289}, issn = {2373-9878}, mesh = {Animals ; Anti-Bacterial Agents ; *Anti-Infective Agents/pharmacology/therapeutic use ; Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis/drug therapy ; }, abstract = {Across years, potential strategies to fight peri-implantitis have been notoriously explored through the antimicrobial coating implant surfaces capable of interfering with the bacterial adhesion process. However, although experimental studies have significantly advanced, no product has been marketed so far. For science to reach the society, the commercialization of research outcomes is necessary to provide real advancement in the biomedical field. Therefore, the aim of this study was to investigate the challenges involved in the development of antimicrobial dental implant surfaces to fight peri-implantitis, through a systematic search. Research articles reporting antimicrobial dental implant surfaces were identified by searching PubMed, Scopus, Web of Science, The Cochrane Library, Embase, and System of Information on Grey Literature in Europe, between 2008 and 2020. A total of 1778 studies were included for quality assessment and the review. An impressive number of 1655 articles (93,1%) comprised in vitro studies, whereas 123 articles refer to in vivo investigations. From those 123, 102 refer to animal studies and only 21 articles were published on the clinical performance of antibacterial dental implant surfaces. The purpose of animal studies is to test how safe and effective new treatments are before they are tested in people. Therefore, the discrepancy between the number of published studies clearly reveals that preclinical investigations still come up against several challenges to overcome before moving forward to a clinical setting. Additionally, researchers need to recognize that the complex journey from lab to market requires more than a great idea and resources to develop a commercial invention; research teams must possess the skills necessary to commercialize an invention.}, } @article {pmid35814646, year = {2022}, author = {Simkovsky, R and Parnasa, R and Wang, J and Nagar, E and Zecharia, E and Suban, S and Yegorov, Y and Veltman, B and Sendersky, E and Schwarz, R and Golden, SS}, title = {Transcriptomic and Phenomic Investigations Reveal Elements in Biofilm Repression and Formation in the Cyanobacterium Synechococcus elongatus PCC 7942.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {899150}, pmid = {35814646}, issn = {1664-302X}, abstract = {Biofilm formation by photosynthetic organisms is a complex behavior that serves multiple functions in the environment. Biofilm formation in the unicellular cyanobacterium Synechococcus elongatus PCC 7942 is regulated in part by a set of small secreted proteins that promotes biofilm formation and a self-suppression mechanism that prevents their expression. Little is known about the regulatory and structural components of the biofilms in PCC 7942, or response to the suppressor signal(s). We performed transcriptomics (RNA-Seq) and phenomics (RB-TnSeq) screens that identified four genes involved in biofilm formation and regulation, more than 25 additional candidates that may impact biofilm formation, and revealed the transcriptomic adaptation to the biofilm state. In so doing, we compared the effectiveness of these two approaches for gene discovery.}, } @article {pmid35811135, year = {2023}, author = {Ferro, AC and Spavieri, JHP and Ribas, BR and Scabelo, L and Jorge, JH}, title = {Do denture cleansers influence the surface roughness and adhesion and biofilm formation of Candida albicans on acrylic resin? Systematic review and meta-analysis.}, journal = {Journal of prosthodontic research}, volume = {67}, number = {2}, pages = {164-172}, doi = {10.2186/jpr.JPR_D_22_00077}, pmid = {35811135}, issn = {2212-4632}, mesh = {*Acrylic Resins ; *Candida albicans ; Dental Materials ; Denture Cleansers/pharmacology ; Sodium Hypochlorite/pharmacology ; Surface Properties ; Denture Bases ; Biofilms ; }, abstract = {PURPOSE: To evaluate the influence of denture cleansers on the surface roughness, Candida albicans adhesion, and biofilm formation on denture base acrylic resins.

STUDY SELECTION: Electronic databases and gray literature were searched using an individual search strategy. In vitro studies that evaluated the effects of immersion in denture cleansers on the surface roughness (µm) and antimicrobial activity (CFU/mL) on samples of heat-polymerized denture base acrylic resins were included.

RESULTS: After screening, 17 studies were included, and a qualitative synthesis was performed. After assessing the risk of bias, only nine studies were included in the meta-analysis. The meta-analysis results showed that the evaluated solutions (0.5% sodium hypochlorite, 1% sodium hypochlorite, alkaline peroxide, and natural substances) did not influence the roughness of the acrylic resin. However, in the qualitative analysis, it was not possible to confirm an association between roughness and C. albicans adhesion and biofilm formation on the acrylic resin samples.

CONCLUSION: Denture cleansers did not affect the surface roughness of denture base acrylic resins.}, } @article {pmid35811023, year = {2022}, author = {Wu, M and Huang, S and Du, J and Li, Y and Jiang, S and Zhan, L and Huang, X}, title = {D-alanylation of lipoteichoic acid contributes to biofilm formation and acidogenesis capacity of Streptococcusmutans.}, journal = {Microbial pathogenesis}, volume = {169}, number = {}, pages = {105666}, doi = {10.1016/j.micpath.2022.105666}, pmid = {35811023}, issn = {1096-1208}, mesh = {Biofilms ; *Lipopolysaccharides/metabolism ; Streptococcus mutans/genetics/metabolism ; *Teichoic Acids/metabolism ; }, abstract = {BACKGROUND: D-alanylation of Lipoteichoic acid (LTA) is considered to be essential for virulence factors expression in Gram-positive microorganism. The effects of the D-alanylation of LTA on biofilm formation and acidogenesis of Streptococcus mutans (S. mutans) are still not clearly understood.

AIM: This study was designed to investigate the impact of D-alanylation of LTA on biofilm formation and acidogenesis of S. mutans and explore the related mechanisms.

METHODS AND MATERIAL: We compared the biofilm formation process by fluorescence microscope observation of LTA D-alanylation blocking strain with that of the wildtype strain. Auto-aggregation, cell surface charge, and polysaccharide production assays were performed to investigate the related mechanisms. pH drop assay and glycolysis pH drop-down analysis were carried out to evaluate the acidogenesis capacity of S. mutans after LTA D-alanylation blocking. To identify the biofilm formation and adhesive-related genes expressions of S. mutans mutant, qRT-PCR was performed.

RESULTS: After blocking off the D-alanylation of LTA, S. mutans could not form the three-dimensional structural biofilm, in which cells were scattered on the substratum as small clusters. The auto-aggregation was prompted due to the mutant strain cell morphology change (*p < 0.05). Furthermore, more negative charges were found on the mutant strain cells surfaces and fewer water-insoluble glucans were produced in mutant biofilm (*p < 0.05). The adhesion capacity of the S. mutans biofilm was impaired after LTA D-alanylation blocking (*p < 0.05). Biofilm formation and adhesive-related genes expressions decreased (*p < 0.05), especially at the early stages of biofilm formation. S. mutans mutant strains exhibited suppressed acidogenesis because its glycolytic activity was impaired.

CONCLUSION: The results of this study suggest that blocking of LTA D-alanylation disrupts normal biofilm formation in S. mutans predominantly if not entirely by altering intercellular auto-aggregation, cell adhesion, and extracellular matrix formation. Moreover, our study results suggest that the LTA D-alanylation plays an important role in S. mutans acidogenesis by altering glycolytic activity. These findings add to the knowledge about mechanisms underlying biofilm formation and acid tolerance in S. mutans.}, } @article {pmid35810597, year = {2022}, author = {Tan, Y and Ma, Y and Fu, S and Zhang, A}, title = {Facile construction of fluorescent C70-COOH nanoparticles with advanced antibacterial and anti-biofilm photodynamic activity.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {234}, number = {}, pages = {112507}, doi = {10.1016/j.jphotobiol.2022.112507}, pmid = {35810597}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/chemistry ; *Methicillin-Resistant Staphylococcus aureus ; *Nanoparticles/chemistry ; *Photochemotherapy ; Photosensitizing Agents/chemistry ; }, abstract = {Photodynamic antibacterial therapy has been considered as one of the most promising treatments to alleviate the spread of multidrug resistant bacterial pathogens. Given the hypoxic environment of infectious tissues, photosensitizers with reduced oxygen-demand could exhibit superiority upon irradiation. Herein reported is a novel C70-based photosensitizers synthesized by the facile one-step thiol-ene reaction. Various characterization techniques were employed to confirm the structural, photoluminescent properties, photostability and biocompatibility of the as-synthesized C70-COOH nanoparticles. Furthermore, they were capable of efficiently producing reactive oxygen species following both the type I and II mechanistic pathways, thus still generating adequate free radicals under hypoxic condition. Therefore, they could approach and destroy the bacterial cell membrane in the presence of visible light, thereby causing cytoplasmic leakage and eventually achieving broad-spectrum inactivation of four representative bacterial strains. Especially, methicillin-resistant Staphylococcus aureus (MRSA) were completely eliminated after merely 10 minutes irradiation, and the formation of its corresponding biofilm were also greatly inhibited by C70-COOH nanoparticles. These results provide new insights and opportunities for the development of hypoxia-tolerant fullerene-based photosensitizers to combat multidrug resistant bacterial and related infections.}, } @article {pmid35808019, year = {2022}, author = {Hosnedlova, B and Kabanov, D and Kepinska, M and B Narayanan, VH and Parikesit, AA and Fernandez, C and Bjørklund, G and Nguyen, HV and Farid, A and Sochor, J and Pholosi, A and Baron, M and Jakubek, M and Kizek, R}, title = {Effect of Biosynthesized Silver Nanoparticles on Bacterial Biofilm Changes in S. aureus and E. coli.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {13}, pages = {}, pmid = {35808019}, issn = {2079-4991}, abstract = {One approach for solving the problem of antibiotic resistance and bacterial persistence in biofilms is treatment with metals, including silver in the form of silver nanoparticles (AgNPs). Green synthesis is an environmentally friendly method to synthesize nanoparticles with a broad spectrum of unique properties that depend on the plant extracts used. AgNPs with antibacterial and antibiofilm effects were obtained using green synthesis from plant extracts of Lagerstroemia indica (AgNPs_LI), Alstonia scholaris (AgNPs_AS), and Aglaonema multifolium (AgNPs_AM). Nanoparticles were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The ability to quench free radicals and total phenolic content in solution were also evaluated. The antibacterial activity of AgNPs was studied by growth curves as well as using a diffusion test on agar medium plates to determine minimal inhibitory concentrations (MICs). The effect of AgNPs on bacterial biofilms was evaluated by crystal violet (CV) staining. Average minimum inhibitory concentrations of AgNPs_LI, AgNPs_AS, AgNPs_AM were 15 ± 5, 20 + 5, 20 + 5 μg/mL and 20 ± 5, 15 + 5, 15 + 5 μg/mL against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, respectively. The E. coli strain formed biofilms in the presence of AgNPs, a less dense biofilm than the S. aureus strain. The highest inhibitory and destructive effect on biofilms was exhibited by AgNPs prepared using an extract from L. indica.}, } @article {pmid35807444, year = {2022}, author = {Cruz, JN and de Oliveira, MS and Andrade, EHA and Rodrigues Lima, R}, title = {Molecular Modeling Approaches Can Reveal the Molecular Interactions Established between a Biofilm and the Bioactive Compounds of the Essential Oil of Piper divaricatum.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {13}, pages = {}, pmid = {35807444}, issn = {1420-3049}, mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; Gelatin/chemistry ; Humans ; *Oils, Volatile/chemistry ; *Piper ; }, abstract = {Molecular modeling approaches are used in a versatile way to investigate the properties of diverse organic and inorganic structures such as proteins, biomolecules, nanomaterials, functionalized nanoparticles, and membranes. However, more detailed studies are needed to understand the molecular nature of interactions established in gelatin biofilms impregnated with bioactive compounds. Because of this, we used computational methods to evaluate how the major compounds of Piper divaricatum essential oil can interact with the gelatin biofilm structure. For this, we used as inspiration the paper published, where various properties of the essential oil impregnated gelatin biofilm P. divaricatum are reported. After our computer simulations, we related our molecular observations to biofilm's structural and mechanical properties. Our results suggest that the major compounds of the essential oil were able to interrupt intermolecular interactions between the chains of the biofilm matrix. However, the compounds also established interactions with the amino acid residues of these chains. Our molecular analyses also explain changes in the structural and mechanical properties of the essential oil-impregnated biofilm. These results can support the planning of functional packaging impregnated with bioactive compounds that can protect food against microorganisms harmful to human health.}, } @article {pmid35807343, year = {2022}, author = {Brożyna, M and Paleczny, J and Kozłowska, W and Ciecholewska-Juśko, D and Parfieńczyk, A and Chodaczek, G and Junka, A}, title = {Chemical Composition and Antibacterial Activity of Liquid and Volatile Phase of Essential Oils against Planktonic and Biofilm-Forming Cells of Pseudomonas aeruginosa.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {13}, pages = {}, pmid = {35807343}, issn = {1420-3049}, support = {PREL.D230.22.003//National Science Centre in Poland/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; *Oils, Volatile/chemistry/pharmacology ; Plankton ; Pseudomonas aeruginosa ; *Rosmarinus ; Tea ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen causing life-threatening, hard-to-heal infections associated with the presence of a biofilm. Essential oils (EOs) are promising agents to combat pseudomonal infections because of the alleged antimicrobial activity of their volatile fractions and liquid forms. Therefore, the purpose of this paper was to evaluate the antibacterial efficacy of both volatile and liquid phases of seven EOs (thyme, tea tree, basil, rosemary, eucalyptus, menthol mint, lavender) against P. aeruginosa biofilm and planktonic cells with the use of a broad spectrum of analytical in vitro methods. According to the study results, the antibacterial activity of EOs in their liquid forms varied from that of the volatile fractions. Overall, liquid and volatile forms of rosemary EO and tea tree EO displayed significant antibiofilm effectiveness. The outcomes indicate that these particular EOs possess the potential to be used in the therapy of P. aeruginosa infections.}, } @article {pmid35807329, year = {2022}, author = {Sønderby, TV and Najarzadeh, Z and Otzen, DE}, title = {Functional Bacterial Amyloids: Understanding Fibrillation, Regulating Biofilm Fibril Formation and Organizing Surface Assemblies.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {13}, pages = {}, pmid = {35807329}, issn = {1420-3049}, support = {8021-00208B and 8021-00133B//Independent Danish Research Council | Natural Sciences/ ; }, mesh = {Amyloid/chemistry ; Amyloidogenic Proteins/chemistry ; Bacterial Proteins/metabolism ; Biofilms ; *Escherichia coli/metabolism ; Humans ; *Neurodegenerative Diseases ; Pseudomonas/metabolism ; }, abstract = {Functional amyloid is produced by many organisms but is particularly well understood in bacteria, where proteins such as CsgA (E. coli) and FapC (Pseudomonas) are assembled as functional bacterial amyloid (FuBA) on the cell surface in a carefully optimized process. Besides a host of helper proteins, FuBA formation is aided by multiple imperfect repeats which stabilize amyloid and streamline the aggregation mechanism to a fast-track assembly dominated by primary nucleation. These repeats, which are found in variable numbers in Pseudomonas, are most likely the structural core of the fibrils, though we still lack experimental data to determine whether the repeats give rise to β-helix structures via stacked β-hairpins (highly likely for CsgA) or more complicated arrangements (possibly the case for FapC). The response of FuBA fibrillation to denaturants suggests that nucleation and elongation involve equal amounts of folding, but protein chaperones preferentially target nucleation for effective inhibition. Smart peptides can be designed based on these imperfect repeats and modified with various flanking sequences to divert aggregation to less stable structures, leading to a reduction in biofilm formation. Small molecules such as EGCG can also divert FuBA to less organized structures, such as partially-folded oligomeric species, with the same detrimental effect on biofilm. Finally, the strong tendency of FuBA to self-assemble can lead to the formation of very regular two-dimensional amyloid films on structured surfaces such as graphite, which strongly implies future use in biosensors or other nanobiomaterials. In summary, the properties of functional amyloid are a much-needed corrective to the unfortunate association of amyloid with neurodegenerative disease and a testimony to nature's ability to get the best out of a protein fold.}, } @article {pmid35806818, year = {2022}, author = {Kudara, H and Kanematsu, H and Barry, DM and Ogawa, A and Kogo, T and Miura, H and Kawai, R and Hirai, N and Kato, T and Yoshitake, M}, title = {Proposal for Some Affordable Laboratory Biofilm Reactors and Their Critical Evaluations from Practical Viewpoints.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {13}, pages = {}, pmid = {35806818}, issn = {1996-1944}, abstract = {Biofilms are a result of bacterial activities and are found everywhere. They often form on metal surfaces and on the surfaces of polymeric compounds. Biofilms are sticky and mostly consist of water. They have a strong resistance to antimicrobial agents and can cause serious problems for modern medicine and industry. Biofilms are composed of extracellular polymeric substances (EPS) such as polysaccharides produced from bacterial cells and are dominated by water at the initial stage. In a series of experiments, using Escherichia coli, we developed three types of laboratory biofilm reactors (LBR) to simulate biofilm formation. For the first trial, we used a rotary type of biofilm reactor for stirring. For the next trial, we tried another rotary type of reactor where the circular plate holding specimens was rotated. Finally, a circular laboratory biofilm reactor was used. Biofilms were evaluated by using a crystal violet staining method and by using Raman spectroscopy. Additionally, they were compared to each other from the practical (industrial) viewpoints. The third type was the best to form biofilms in a short period. However, the first and second were better from the viewpoint of "ease of use". All of these have their own advantages and disadvantages, respectively. Therefore, they should be properly selected and used for specific and appropriate purposes in the future.}, } @article {pmid35806655, year = {2022}, author = {Vladkova, TG and Monov, DM and Akuzov, DT and Ivanova, IA and Gospodinova, D}, title = {Comparative Study of the Marinobacter hydrocarbonoclasticus Biofilm Formation on Antioxidants Containing Siloxane Composite Coatings.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {13}, pages = {}, pmid = {35806655}, issn = {1996-1944}, support = {КП-06-КОСТ 12/4.12.2020л//Bulgarian National Scientific Fund/ ; }, abstract = {No systematic study of antioxidant containing coatings and their anti-biofilm action has been reported so far. The utilization of antioxidants in protective coatings to inhibit marine biofilm formation is a current challenge. The aim of this preliminary study was to prepare, characterize and compare the efficiency of low adhesive siloxane composite coatings equally loaded with different antioxidants against mono-species biofilms formation. Most often participating in the marine biofilms formation, Marinobacter hydrocarbonoclasticus was the test bacterium. Both the biofilm covered surface area (BCSA) and corrected total cell fluorescence (CTCF) (by fluorescent microscopy) were selected as the parameters for quantification of the biofilm after 1 h and 4 h incubation. Differing extents of altered surface characteristics (physical-chemical; physical-mechanical) and the specific affection of M. hydrocarbonoclasticus biofilm formation in both reduction and stimulation, were found in the studied antioxidant containing coatings, depending on the chemical nature of the used antioxidant. It was concluded that not all antioxidants reduce mono-species biofilm formation; antioxidant chemical reactivity stipulates the formation of an altered vulcanization network of the siloxane composites and thus microbial adhesion which influences the surface characteristics of the vulcanized coatings; and low surface energy combined with a low indentation elastic modulus are probably pre-requisites of low microbial adhesion.}, } @article {pmid35805711, year = {2022}, author = {Odorici, A and Colombari, B and Bellini, P and Meto, A and Venturelli, I and Blasi, E}, title = {Novel Options to Counteract Oral Biofilm Formation: In Vitro Evidence.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {13}, pages = {}, pmid = {35805711}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents ; Biofilms ; Candida albicans ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {Biofilm production on biotic and abiotic surfaces is crucial in the pathogenesis of most infections, particularly those occurring in the oral cavity. Its prevention and/or control may greatly facilitate the management of patients with oral diseases. Here, the antibiofilm activity of a biomimetic hydroxyapatite and a natural compound, MicroRepair (MicroR) and pomegranate (PomeGr), respectively, was assessed. By luminescence/fluorescence-based assays, Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) were tested for biofilm production in the presence of MicroR and/or PomeGr. We found that both MicroR and PomeGr could affected biofilm production; however, the efficacy of the two, given alone or in combination, varied according to the microbial agent considered. These data open to clinical studies aimed at defining the most efficacious protocols to counteract oral biofilm-associated infections.}, } @article {pmid35804756, year = {2022}, author = {Hu, L and Dong, Q and Li, Z and Ma, Y and Aslam, MZ and Liu, Y}, title = {Modelling the Adhesion and Biofilm Formation Boundary of Listeria monocytogenes ST9.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {13}, pages = {}, pmid = {35804756}, issn = {2304-8158}, support = {32102095//National Natural Science Foundation of China/ ; }, abstract = {Listeria monocytogenes is a major foodborne pathogen that can adhere to or form a biofilm on food contact surfaces, depending on the environmental conditions. The purpose of this work is to determine the adhesion and biofilm formation boundaries for L. monocytogenes ST9 under the combination environments of temperature (5, 15, and 25 °C), NaCl concentration (0%, 3%, 6%, and 9% (w/v)) and pH (5.0, 6.0, 7.0, and 8.0). The probability models of adhesion and biofilm formation were built using the logistic regression. For adhesion, only the terms of linear T and NaCl are significant for L. monocytogenes ST9 (p < 0.05), whereas the terms of linear T, NaCl, and pH, and the interaction between T and pH were significant for biofilm formation (p < 0.05). By analyzing contour maps and their surface plots for two different states, we discovered that high temperature promoted adhesion and biofilm formation, whereas excessive NaCl concentration inhibited both of them. With a stringent threshold of 0.1667, the accuracy rate for identifying both adhesion/no-adhesion and biofilm formation/no-biofilm formation events were 0.929, indicating that the probability models are reasonably accurate in predicting the adhesion and biofilm formation boundary of L. monocytogenes ST9. The boundary model may provide a useful way for determining and further controlling L. monocytogenes adhesion and biofilm formation in various food processing environments.}, } @article {pmid35804733, year = {2022}, author = {Dong, Q and Sun, L and Fang, T and Wang, Y and Li, Z and Wang, X and Wu, M and Zhang, H}, title = {Biofilm Formation of Listeria monocytogenes and Pseudomonas aeruginosa in a Simulated Chicken Processing Environment.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {13}, pages = {}, pmid = {35804733}, issn = {2304-8158}, support = {32102095//the National Natural Science Foundation of China/ ; }, abstract = {This study aims to investigate the mono- and dual-species biofilm formation of Listeria monocytogenes and Pseudomonas aeruginosa incubated in different culture mediums, inoculum ratios, and incubation time. The planktonic cell population and motility were examined to understand the correlation with biofilm formation. The results showed that chicken juice significantly inhibited the biofilm formation of L. monocytogenes (p < 0.05). Pseudomonas aeruginosa was the dominant bacteria in the dual-species biofilm formation in the trypticase soy broth medium. The dynamic changes in biofilm formation were not consistent with the different culture conditions. The growth of planktonic L. monocytogenes and P. aeruginosa in the suspension was inconsistent with their growth in the biofilms. There was no significant correlation between motility and biofilm formation of L. monocytogenes and P. aeruginosa. Moreover, scanning electron microscopy (SEM) results revealed that the biofilm structure of L. monocytogenes was loose. At the same time, P. aeruginosa formed a relatively dense network in mono-species biofilms in an initial adhesion stage (24 h). SEM results also showed that P. aeruginosa was dominant in the dual-species biofilms. Overall, these results could provide a theoretical reference for preventing and controlling the biofilm formation of L. monocytogenes and P. aeruginosa in the food processing environment in the future.}, } @article {pmid35804023, year = {2022}, author = {Tyrikos-Ergas, T and Gim, S and Huang, JY and Pinzón Martín, S and Varón Silva, D and Seeberger, PH and Delbianco, M}, title = {Synthetic phosphoethanolamine-modified oligosaccharides reveal the importance of glycan length and substitution in biofilm-inspired assemblies.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {3954}, pmid = {35804023}, issn = {2041-1723}, mesh = {*Biofilms ; Cellulose/metabolism ; *Escherichia coli/genetics/metabolism ; Ethanolamines ; Oligosaccharides/metabolism ; }, abstract = {Bacterial biofilm matrices are nanocomposites of proteins and polysaccharides with remarkable mechanical properties. Efforts understanding and tuning the protein component have been extensive, whereas the polysaccharide part remained mostly overlooked. The discovery of phosphoethanolamine (pEtN) modified cellulose in E. coli biofilms revealed that polysaccharide functionalization alters the biofilm properties. To date, the pattern of pEtN cellulose and its mode of interactions with proteins remains elusive. Herein, we report a model system based on synthetic epitomes to explore the role of pEtN in biofilm-inspired assemblies. Nine pEtN-modified oligosaccharides were synthesized with full control over the length, degree and pattern of pEtN substitution. The oligomers were co-assembled with a representative peptide, triggering the formation of fibers in a length dependent manner. We discovered that the pEtN pattern modulates the adhesion of biofilm-inspired matrices, while the peptide component controls its stiffness. Unnatural oligosaccharides tune or disrupt the assembly morphology, revealing interesting targets for polysaccharide engineering to develop tunable bio-inspired materials.}, } @article {pmid35802194, year = {2022}, author = {Başkan, C and Sırıken, B and Tüfekci, EF and Kılınç, Ç and Ertürk, Ö and Erol, İ}, title = {Presence of quorum sensing system, virulence genes, biofilm formation and relationship among them and class 1 integron in carbapenem-resistant clinical Pseudomonas aeruginosa isolates.}, journal = {Archives of microbiology}, volume = {204}, number = {8}, pages = {464}, pmid = {35802194}, issn = {1432-072X}, mesh = {Bacterial Proteins/genetics ; Biofilms ; Carbapenems/pharmacology ; Drug Resistance, Bacterial ; *Integrons/genetics ; *Pseudomonas aeruginosa/drug effects/genetics ; *Quorum Sensing/genetics ; Virulence/genetics ; *Virulence Factors/genetics ; }, abstract = {Carbapenems are the most effective agents for treating clinical P. aeruginosa (PsA) infections. During an infection, a quorum-sensing (QS) system and its regulating virulence genes have a great role. The aim of the study was to detect the presence of a las and rhl QS system and related virulence genes, biofilm formation and a class 1 (Cls1) integron. A total of 52 carbapenem-resistant PsA (CRPsA) isolates obtained from Kastamonu, Turkey was analyzed. For the isolation and identification of CRPsA isolates, a conventional culture method, an automated VITEK-2 compact system, and oprL gene-based molecular technique were applied. The two QS system genes were detected in 51 (98.1%), and co-existed of four two QS system genes (lasI/R and rhIl/R genes) were determined in 41 (78.8%) of the isolates. algD, lasB, toxA and aprA genes were detected in between 46.1 and 88.5%, and co-existence of four two QS system genes with four virulence genes were detected in 40.4% of the isolates. Biofilm formation using microtiter plate assay and slime production using Congo Red Agar and Cls1 integron were determined in 84.6%, 67.3% and 51.9% of the isolates, respectively. According to statistical analyses results, there was a significant positive correlation (p < .10) between the las and the rhl systems and a strongly and positive correlation (p < .01 or p < .05) between the rhl system-three virulence genes and slime production-and among some virulence genes. In conclusion, the CRPsA isolates tested in the study are highly virulent and QS systems have a significant role in pathogenesis.}, } @article {pmid36339506, year = {2021}, author = {Liu, D and Wang, Y and Wang, X and Ou, D and Ling, N and Zhang, J and Wu, Q and Ye, Y}, title = {Role of the multiple efflux pump protein TolC on growth, morphology, and biofilm formation under nitric oxide stress in Cronobacter malonaticus.}, journal = {JDS communications}, volume = {2}, number = {3}, pages = {98-103}, pmid = {36339506}, issn = {2666-9102}, abstract = {Nitric oxide (NO) is a biological signal molecule that can control and prevent the growth of most pathogens. Cronobacter species are a group of gram-negative foodborne pathogens that cause severe diseases, including neonatal meningitis, septicemia, and necrotizing enterocolitis, especially among newborns and infants consuming contaminated powdered infant formula. Cronobacter species might be tolerant to NO, resulting in severe infections. However, the specific mechanism of tolerance to NO in Cronobacter species is unclear. Here, we explore the effects of a key component, the protein TolC, of a multiple efflux pump on the growth, morphological changes, and biofilm formation of Cronobacter malonaticus under NO stress. We found that deletion of tolC resulted in a decreased growth rate under 100 mM sodium nitroprusside (NO donor) and led to more disruptive morphological injury to the bacterial cells. Furthermore, C. malonaticus lacking the TolC protein (ΔtolC mutant) showed weaker biofilm formation than the wild-type strain under normal or NO stress conditions. We have proved that TolC plays an important role in cell growth and biofilm formation of C. malonaticus. Therefore, our results may provide valuable theoretical basis for formulating clinical guidelines for treatment of disease caused by C. malonaticus and ensuring food safety.}, } @article {pmid36051866, year = {2021}, author = {Fu, J and Hall, S and Boon, EM}, title = {Recent evidence for multifactorial biofilm regulation by heme sensor proteins NosP and H-NOX.}, journal = {Chemistry letters}, volume = {50}, number = {5}, pages = {1095-1103}, pmid = {36051866}, issn = {0366-7022}, support = {R01 GM118894/GM/NIGMS NIH HHS/United States ; T32 GM136572/GM/NIGMS NIH HHS/United States ; }, abstract = {Heme is involved in signal transduction by either acting as a cofactor of heme-based gas/redox sensors or binding reversely to heme-responsive proteins. Bacteria respond to low concentrations of nitric oxide (NO) to modulate group behaviors such as biofilms through the well-characterized H-NOX family and the newly discovered heme sensor protein NosP. NosP shares functional similarities with H-NOX as a heme-based NO sensor; both regulate two-component systems and/or cyclic-di-GMP metabolizing enzymes, playing roles in processes such as quorum sensing and biofilm regulation. Interestingly, aside from its role in NO signaling, recent studies suggest that NosP may also sense labile heme. In this Highlight Review, we briefly summarize H-NOX-dependent NO signaling in bacteria, then focus on recent advances in NosP-mediated NO signaling and labile heme sensing.}, } @article {pmid36147291, year = {2020}, author = {Litt, PK and Kakani, R and Jadeja, R and Saha, J and Kountoupis, T and Jaroni, D}, title = {Effectiveness of Bacteriophages Against Biofilm-Forming Shiga-Toxigenic Escherichia coli on Leafy Greens and Cucumbers.}, journal = {PHAGE (New Rochelle, N.Y.)}, volume = {1}, number = {4}, pages = {213-222}, pmid = {36147291}, issn = {2641-6549}, abstract = {Background: Shiga-toxigenic Escherichia coli (STEC) have caused several produce-associated outbreaks, making it challenging to control these pathogens. Bacteriophages could serve as effective biocontrol. Materials and Methods: Spinach, lettuce, and cucumbers, inoculated with STEC (O157, O26, O45, O103, O111, O121, O145), were treated with lytic bacteriophages and stored at 4°C for 3 days. Surviving STEC were enumerated and observed under scanning electron microscope (SEM), and data analyzed using one-way analysis of variance (ANOVA) (p < 0.05). Results: Bacteriophage treatments significantly reduced STEC populations, compared with the control (p < 0.05). On spinach and romaine, STEC O26, O45, and O103 were reduced to undetectable levels and STEC O157, O111, O121, and O145 by ∼2 logs CFU/cm[2]. Multiserotype phage cocktail reduced STEC on leafy greens by 1.4 CFU/cm[2] and on cucumbers by 1.7 logs CFU/cucumber. Clusters of STEC cells, surrounded by extracellular matrix, were observed under SEM of positive control, whereas phage-treated produce surface showed fewer cells, with cellular damage. Conclusions: Bacteriophages could be utilized as biocontrol against STEC on fresh produce.}, } @article {pmid36120175, year = {2020}, author = {Jia, F and Sun, MY and Zhang, XJ and Zhou, XZ}, title = {Total alkaloids of Sophora alopecuroides- and matrine-induced reactive oxygen species impair biofilm formation of Staphylococcus epidermidis and increase bacterial susceptibility to ciprofloxacin.}, journal = {Chinese herbal medicines}, volume = {12}, number = {4}, pages = {390-398}, pmid = {36120175}, issn = {2589-3610}, abstract = {OBJECTIVE: To investigate the mechanism by which total alkaloids of Sophora alopecuroides (TASA) and matrine (MT) impair biofilm to increase the susceptibility of Staphylococcus epidermidis (S. epidermidis) to ciprofloxacin.

METHODS: The minimum biofilm inhibitory concentration (mBIC) was determined using a 2-fold dilution method. Structure of biofilm of S. epidermidis was examined by Confocal Laser Scanning Microscope (CLSM). The cellular reactive oxygen species (ROS) was determined using a DCFH-DA assay. The key factors related to the regulation of ROS were accessed using respective kits.

RESULTS: TASA and MT were more beneficial to impair biofilm of S. epidermidis than ciprofloxacin (CIP) (P < 0.05). TASA and MT were not easily developed resistance to biofilm-producing S. epidermidis. The mBIC of CIP decreased by 2-6-fold following the treatment of sub-biofilm inhibitory concentration (sub-BIC) TASA and MT, whereas the mBIC of CIP increased by 2-fold following a treatment of sub-BIC CIP from the first to sixth generations. TASA and MT can improve the production of ROS in biofilm-producing S. epidermidis. The ROS content was decreased 23%-33% following the treatment of sub-mBIC CIP, whereas ROS content increased 7%-24% following treatment with TASA + CIP and MT + CIP combination from the first to sixth generations. Nitric oxide (NO) as a ROS, which was consistent with the previously confirmed relationship between ROS and drug resistance. Related regulatory factors-superoxide dismutase (SOD) and glutathione peroxidase (GSH) could synergistically maintain the redox balance in vivo.

CONCLUSION: TASA and MT enhanced reactive oxygen species to restore the susceptibility of S. epidermidis to ciprofloxacin.}, } @article {pmid35800390, year = {2022}, author = {Shariati, A and Chegini, Z and Ghaznavi-Rad, E and Zare, EN and Hosseini, SM}, title = {PLGA-Based Nanoplatforms in Drug Delivery for Inhibition and Destruction of Microbial Biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {926363}, pmid = {35800390}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms ; *Glycols/pharmacology ; Microbial Sensitivity Tests ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry ; Pseudomonas aeruginosa ; }, abstract = {The biofilm community of microorganisms has been identified as the dominant mode of microbial growth in nature and a common characteristic of different microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. The biofilm structure helps in the protection from environmental threats including host immune system and antimicrobial agents. Thus, the biofilm community has led to a higher prevalence of multidrug-resistant (MDR) strains in recent years. In this regard, the use of a new class of antibiotics, natural compounds, and anti-biofilm enzymes has been considered for the destruction of the microbial biofilm. However, different drawbacks such as low penetration, high susceptibility to degradation, instability, and poor solubility in aqueous solutions limit the use of anti-biofilm agents (ABAs) in a clinical setting. As such, recent studies have been using poly lactic-co-glycolic acid (PLGA)-based nanoplatforms (PLGA NPFs) for delivery of ABAs that have reported promising results. These particles, due to proper drug loading and release kinetics, could suppress microbial attachment, colonization, and biofilm formation for a long time. Additionally, PLGA NPFs, because of the high drug-loading efficiencies, hydrophilic surface, negative charge, and electrostatic interaction, lead to effective penetration of antibiotics to the deeper layer of the biofilm, thereby eliminating the microbial biofilm. Thus, PLGA NPFs could be considered as a potential candidate for coating catheters and other medical material surfaces for inhibition and destruction of the microbial biofilm. However, the exact interaction of PLGA NPFs and the microbial biofilm should be evaluated in animal studies. Additionally, a future goal will be to develop PLGA formulations as systems that can be used for the treatment of the MDR microbial biofilm, since the exact interactions of PLGA NPFs and these biofilm structures are not elucidated. In the present review article, we have discussed various aspects of PLGA usage for inhibition and destruction of the microbial biofilm along with different methods and procedures that have been used for improving PLGA NPF efficacy against the microbial biofilm.}, } @article {pmid35800142, year = {2022}, author = {Jakovljević, VD and Radojević, ID and Grujić, SM and Ostojić, AM}, title = {Response of selected microbial strains and their consortia to the presence of automobile paints: Biofilm growth, matrix protein content and hydrolytic enzyme activity.}, journal = {Saudi journal of biological sciences}, volume = {29}, number = {8}, pages = {103347}, pmid = {35800142}, issn = {1319-562X}, abstract = {The goal of the current study was to examine the effects of pollutants (White color - CP; Metallic red color - FM; Thinner - CN; Thinner for rinsing paint - MF; Basic color (primer) - FH) originating from the automotive industry on the biofilm growth, matrix protein content, and activity of the hydrolytic enzymes of selected microbial strains in laboratory conditions that mimic the bioreactor conditions. The chosen microorganisms (bacteria, yeasts, and fungi) were isolated from automotive industry wastewater. Pure microbe cultures and their consortia were injected into AMB Media carriers and developed into biofilms. The use of AMB media carriers has been linked to an increase in the active surface area colonized by microorganisms. Afterwards, the carriers were transferred to Erlenmeyer flasks with nutrient media and pollutants at a concentration of 200 μL/mL. The current study found that, depending on the microbial strain, development phase, and chemical structure, the assessed pollutants had an inhibitory or stimulatory influence on the growth of single cultures and their consortia. Statistical analysis found positive correlations between the protein content in the matrix and the biofilm biomass of Rhodotorula mucilaginosa and consortia in CP and FH media, respectively. The proteolytic activity of Candida utilis was very pronounced in media with MF and CN. The best alkaline phosphatase activity (ALP) was achieved in the CN medium of R. mucilaginosa. Acid invertase activity was the highest in the FM and CP media of Escherichia coli and consortia, respectively, whereas the highest alkaline invertase activity was measured in the MF medium of E. coli. A positive correlation was confirmed between ALP and the biofilm biomass of R. mucilaginosa in CP and CN media, as well as between ALP and the biofilm biomass of Penicillium expansum in FM medium. The findings provide novel insights into the extracellular hydrolytic activity of the investigated microbial strains in the presence of auto paints, as well as a good platform for subsequent research into comprehensive biofilm profiling using modern methodologies.}, } @article {pmid35799278, year = {2022}, author = {Jacques, M and Malouin, F}, title = {One Health-One Biofilm.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {51}, pmid = {35799278}, issn = {1297-9716}, support = {Discovery grant//Natural Sciences and Engineering Research Council of Canada/ ; CREATE grant//Natural Sciences and Engineering Research Council of Canada/ ; Programme regroupements stratégiques//Fonds de Recherche du Québec - Nature et Technologies/ ; }, mesh = {Animals ; *Biofilms ; Environmental Microbiology ; Humans ; *One Health ; }, abstract = {Bacterial biofilms are structured clusters of bacterial cells enclosed in a self-produced polymer matrix that are attached to a biotic or abiotic surface. This structure protects bacteria from hostile environmental conditions. There are also accumulating reports about bacterial aggregates associated but not directly adherent to surfaces. Interestingly, these bacterial aggregates exhibit many of the same phenotypes as surface-attached biofilms. Surface-attached biofilms as well as non-attached aggregates are ubiquitous and found in a wide variety of natural and clinical settings. This strongly suggests that biofilm/aggregate formation is important at some steps in the bacterial lifecycle. Biofilm/aggregate formation might therefore be important for some bacterial species for persistence within their host or their environment, while for other bacterial species it might be more important for persistence in the environment between infection of different individuals or even between infection of different hosts (humans or animals). This is strikingly similar to the One Health concept which recognizes that the health and well-being of humans, animals and the environment are intricately linked. We would like to propose that within this One Health concept, the One Biofilm concept also exists, where biofilm/aggregate formation in humans, animals and the environment are also intricately linked. Biofilm/aggregates could represent the unifying factor underneath the One Health concept. The One Biofilm concept would support that biofilm/aggregate formation might be important for persistence during infection but might as well be even more important for persistence in the environment and for transmission between different individuals/different hosts.}, } @article {pmid35798749, year = {2022}, author = {Kaleta, MF and Petrova, OE and Zampaloni, C and Garcia-Alcalde, F and Parker, M and Sauer, K}, title = {A previously uncharacterized gene, PA2146, contributes to biofilm formation and drug tolerance across the ɣ-Proteobacteria.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {54}, pmid = {35798749}, issn = {2055-5008}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Drug Tolerance ; *Gammaproteobacteria/metabolism ; *Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa ; }, abstract = {Transcriptomic studies have revealed a large number of uncharacterized genes that are differentially expressed in biofilms, which may be important in regulating biofilm phenotypes such as resistance to antimicrobial agents. To identify biofilm genes of unknown function in P. aeruginosa, we made use of RNA-seq and selected 27 uncharacterized genes that were induced upon biofilm growth. Biofilms by respective mutants were subsequently analyzed for two biofilm characteristics, the biofilm architecture and drug susceptibility. The screen revealed 12 out of 27 genes to contribute to biofilm formation and 13 drug susceptibility, with 8 genes affecting both biofilm phenotypes. Amongst the genes affecting both biofilm phenotypes was PA2146, encoding a small hypothetical protein that exhibited some of the most substantial increases in transcript abundance during biofilm growth by P. aeruginosa PAO1 and clinical isolates. PA2146 is highly conserved in ɣ-proteobacteria. Inactivation of PA2146 affected both biofilm phenotypes in P. aeruginosa PAO1, with inactivation of homologs in Klebsiella pneumoniae and Escherichia coli having similar effects. Heterologous expression of PA2146 homologs complemented the P. aeruginosa ∆PA2146, suggesting that PA2146 homologs substitute for and play a similar role as PA2146 in P. aeruginosa.}, } @article {pmid35798170, year = {2022}, author = {Chen, S and Yang, D and Wang, Q and Huang, X and Ren, H and Xu, K}, title = {Study on the advanced nitrogen removal under low temperature by biofilm on weak magnetic carriers.}, journal = {Bioresource technology}, volume = {360}, number = {}, pages = {127580}, doi = {10.1016/j.biortech.2022.127580}, pmid = {35798170}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Magnetic Phenomena ; *Nitrogen ; Temperature ; Wastewater/analysis ; }, abstract = {The advanced nitrogen removal under low temperature is inhibited because of reduction of the microbial activity. Packed bed reactors filled with different magnetic carriers (0, 0.3, 0.6, 0.9 mT) were constructed to enhance advanced denitrification under low temperature (5 ℃). Results showed that 0.3 and 0.9 mT carriers significantly improved denitrification, indicating the "window" effect. Total nitrogen removals were increased by 6.96% and 8.25%, and NO2[-] accumulation decreased by 25.70% and 13.90% in 0.3 and 0.9 mT reactors, respectively. Analysis of enzyme activity and electron transport chain showed that 0.3 mT carrier mainly increased NIR activity by improving compound III and cytC abundance while 0.9 mT carrier mainly increased NAR activity by improving compound I and NADH abundance, indicating different pathways. Similar microbial community in 0.3 and 0.9 mT reactors were revealed. Overall, weak magnetic carriers can be used to enhance advanced nitrogen removal under low temperature.}, } @article {pmid35798169, year = {2022}, author = {Zhao, L and Zhao, D}, title = {Hydrolyzed polyacrylamide biotransformation during the formation of anode biofilm in microbial fuel cell biosystem: Bioelectricity, metabolites and functional microorganisms.}, journal = {Bioresource technology}, volume = {360}, number = {}, pages = {127581}, doi = {10.1016/j.biortech.2022.127581}, pmid = {35798169}, issn = {1873-2976}, mesh = {Acrylic Resins ; *Bioelectric Energy Sources ; Biofilms ; Biotransformation ; Electricity ; Electrodes ; Wastewater ; }, abstract = {The anode biofilm serves as the core dominating the performance of microbial fuel cell (MFC) biosystem. This research provides new insights into hydrolyzed polyacrylamide (HPAM) biotransformation during the formation of anode biofilm. The current density, coulombic efficiency, voltage, power density, volatile fatty acid (VFA) production and total nitrogen (TN) removal enhanced with the thickening of biofilm (1-6 cm), and the maximums achieved 146 mA·m[-2], 47.3%, 8.76 V, 1.28 W·m[-2], 184 mg·L[-1] and 84.6%, respectively. HPAM concentration descended from 508 mg·L[-1] to 83.3 mg·L[-1] after 60 days. HPAM was metabolized into VFAs, N2, NO2[-]-N and NO3[-]-N, thereby releasing electrons. Laccase and tyrosine/tryptophan protein induced HPAM metabolism and bioelectricity production. The microbial functions involving HPAM biotransformation and bioelectricity generation were clarified. The alternative resource recovery, techno-economic comparison and development direction of MFC biosystem were discussed to achieve the synchronization of HPAM-containing wastewater treatment and bioelectricity generation based on MFC biosystem.}, } @article {pmid35797946, year = {2022}, author = {Asghar, S and Ahmed, A and Khan, S and Lail, A and Shakeel, M}, title = {Genomic characterization of lytic bacteriophages A¥L and A¥M infecting ESBL K. pneumoniae and its therapeutic potential on biofilm dispersal and in-vivo bacterial clearance.}, journal = {Microbiological research}, volume = {262}, number = {}, pages = {127104}, doi = {10.1016/j.micres.2022.127104}, pmid = {35797946}, issn = {1618-0623}, mesh = {Animals ; *Bacteriophages/genetics ; Biofilms ; Genomics ; Klebsiella pneumoniae/genetics ; Mice ; *Siphoviridae ; }, abstract = {BACKGROUND: The emerging carbapenem resistance and extended spectrum β-lactamases (ESBL) producing strains of Klebsiella pneumoniae, are one of the critical pathogens for which novel therapeutic alternatives are required on urgent basis. Biofilm formation further aids in virulence due to impermeable nature. Bacteriophages are bacterial predators which due to their selective, and nontoxic nature can be used as an alternate to counter MDR infections. Hence, the current study was intended to isolate, characterize, and develop phage cocktail as a possible therapy against ESBL K. pneumoniae.

MATERIAL AND METHOD: The two-novel bacteriophage A¥L and A¥M were isolated from environmental samples and characterized for host specificity and physicochemical stability (i.e., temperature and pH). Isolated phages alone or together as cocktail was further evaluated for in vitro biofilm eradication and infection clearance using in vivo murine model. Whole genome sequencing was performed for identification, evolutionary relationship, and bioinformatics analysis.

RESULT: The isolated phage A¥L and A¥M belonged to Myoviridae and Siphoviridae family, respectively and showed good thermal (-20, 37, 45, and 60̊C) and pH (5, 7, 9, and 11) stability. At MOI of 0.001, both phages displayed short eclipse period of 5 and 10 min, respectively. Phages alone or together as cocktail showed 50-70% eradication of 48 h mature biofilm. Majority of the cells within biofilm was found dead as evinced from live dead staining. Atomic force and scanning electron microscopic analysis showed distorted biofilm with ruptured cells. The isolated phage or their cocktail significantly inhibited K. pneumoniae associated mortality in intraperitoneal inoculated mice model CONCLUSION: These findings imply that the phage might be a good option for eliminating K. pneumoniae infections and further studies could help in development of these phage as a bio-control product.}, } @article {pmid35796946, year = {2022}, author = {Bharathi, SD and Dilshani, A and Rishivanthi, S and Khaitan, P and Vamsidhar, A and Jacob, S}, title = {Resource Recycling, Recovery, and Xenobiotic Remediation from E-wastes Through Biofilm Technology: A Review.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35796946}, issn = {1559-0291}, abstract = {Around 50 million tonnes of electronic waste has been generated globally per year, causing an environmental hazard and negative effects on human health, such as infertility and thyroid disorders in adults, endocrine and neurological damage in both animals and humans, and impaired mental and physical development in children. Out of that, only 15% is recycled each year and the remaining is disposed of in a landfill, illegally traded or burned, and treated in a sub-standard way. The processes of recycling are challenged by the presence of brominated flame retardants. The different recycling technologies such as the chemical and mechanical methods have been well studied, while the most promising approach is the biological method. The process of utilizing microbes to decontaminate and degrade a wide range of pollutants into harmless products is known as bioremediation and it is an eco-friendly, cost-effective, and sustainable method. The bioremediation process is significantly aided by biofilm communities attached to electronic waste because they promote substrate bioavailability, metabolite transfer, and cell viability, all of which accelerate bioleaching and biodegradation. Microbes existing in biofilm mode relatable to free-floating planktonic cells are advantageous of bioremediation due to their tolerant ability to environmental stress and pollutants through diverse catabolic pathways. This article discusses the harmful effects of electronic waste and its management using biological strategies especially biofilm-forming communities for resource recovery.}, } @article {pmid35793165, year = {2022}, author = {Hu, MX and He, F and Zhao, ZS and Guo, YX and Ma, XK and Tu, CK and Teng, H and Chen, ZX and Yan, H and Shao, X}, title = {Electrospun Nanofibrous Membranes Accelerate Biofilm Formation and Probiotic Enrichment: Enhanced Tolerances to pH and Antibiotics.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {28}, pages = {31601-31612}, doi = {10.1021/acsami.2c04540}, pmid = {35793165}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Hydrogen-Ion Concentration ; *Nanofibers/chemistry ; Plankton ; *Probiotics ; }, abstract = {Biofilms are the oldest, most successful, and most widely distributed form of microorganism life on earth, existing even in extreme environments. Presently, probiotics in biofilm phenotype are thought as the most advanced fourth-generation probiotics. However, high-efficiency and large-scale biofilm enrichment in an artificial way is difficult. Here, fibrous membranes as probiotic biofilm-enriching materials are studied. Electrospun cellulose acetate nanofibrous membranes with nano-sized fibers show outstanding superiority over fibrous membranes with micron-sized fibers in Lactobacillus paracasei biofilm enrichment. The special 3D structure of electrospun nanofibrous membranes makes other facilitating biofilm formation factors insignificant. With a suitable scaffold/culture medium ratio, nearly 100% of L. paracasei cells exist as biofilm phenotype on the membrane from the very beginning, not planktonic state. L. paracasei biofilms possess a potential for long-term survival and high tolerances toward strong acidic and alkali conditions and antibiotics. RNA sequencing results explain why L. paracasei biofilms possess high tolerances toward harsh environments as compared to planktonic L. paracasei. Electrospun nanofibrous membranes can serve as powerful biofilm-enriching scaffolds for probiotics and other valuable microbes.}, } @article {pmid35791082, year = {2022}, author = {Abduljalil, H and Bakri, A and Albashaireh, K and Alshanta, OA and Brown, JL and Sherry, L and Kean, R and Nile, C and McLean, W and Ramage, G}, title = {Screening the Tocriscreen™ bioactive compound library in search for inhibitors of Candida biofilm formation.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {130}, number = {9}, pages = {568-577}, pmid = {35791082}, issn = {1600-0463}, support = {//Jordan University of Science and Technology/ ; //Ministry of Health Malaysia/ ; //Ministry of Higher Education/ ; }, mesh = {*Antifungal Agents/pharmacology ; Biofilms ; *Candida ; Candida albicans/physiology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Biofilms formed by Candida species present a significant clinical problem due to the ineffectiveness of many conventional antifungal agents, in particular the azole class. We urgently require new and clinically approved antifungal agents quickly for treatment of critically ill patients. To improve efficiency in antifungal drug development, we utilized a library of 1280 biologically active molecules within the Tocriscreen 2.0 Micro library. Candida auris NCPF 8973 and Candida albicans SC5314 were initially screened for biofilm inhibitory activity using metabolic and biomass quantitative assessment methods, followed up by targeted evaluation of five selected hits. The initial screening (80% metabolic inhibition rate) revealed that there was 90 and 87 hits (approx. 7%) for C. albicans and C. auris, respectively. Additionally, all five compounds selected from the initial hits exhibited a biofilm inhibition effect against several key Candida species tested, including C. glabrata and C. krusei. Toyocamycin displayed the most potent activity at concentrations as low as 0.5 μg/mL, though was limited to inhibition. Darapladib demonstrated an efficacy for biofilm inhibition and treatment at a concentration range from 8 to 32 μg/mL and from 16 to 256 μg/mL, respectively. Combinational testing with conventional antifungals against C. albicans strains demonstrated a range of synergies for planktonic cells, and notably an anti-biofilm synergy for darapladib and caspofungin. Together, these data provide new insights into antifungal management possibilities for Candida biofilms.}, } @article {pmid35790729, year = {2022}, author = {Xiu, W and Wan, L and Yang, K and Li, X and Yuwen, L and Dong, H and Mou, Y and Yang, D and Wang, L}, title = {Potentiating hypoxic microenvironment for antibiotic activation by photodynamic therapy to combat bacterial biofilm infections.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {3875}, pmid = {35790729}, issn = {2041-1723}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacterial Infections ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; *Photochemotherapy ; }, abstract = {Traditional antibiotic treatment has limited efficacy for the drug-tolerant bacteria present in biofilms because of their unique metabolic conditions in the biofilm infection microenvironment. Modulating the biofilm infection microenvironment may influence the metabolic state of the bacteria and provide alternative therapeutic routes. In this study, photodynamic therapy is used not only to eradicate methicillin-resistant Staphylococcus aureus biofilms in the normoxic condition, but also to potentiate the hypoxic microenvironment, which induces the anaerobic metabolism of methicillin-resistant Staphylococcus aureus and activates the antibacterial activity of metronidazole. Moreover, the photodynamic therapy-activated chemotherapy can polarize the macrophages to a M2-like phenotype and promote the repair of the biofilm infected wounds in mice. This biofilm infection microenvironment modulation strategy, whereby the hypoxic microenvironment is potentiated to synergize photodynamic therapy with chemotherapy, provides an alternative pathway for efficient treatment of biofilm-associated infections.}, } @article {pmid35787627, year = {2022}, author = {Blanco-Cabra, N and Movellan, J and Marradi, M and Gracia, R and Salvador, C and Dupin, D and Loinaz, I and Torrents, E}, title = {Neutralization of ionic interactions by dextran-based single-chain nanoparticles improves tobramycin diffusion into a mature biofilm.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {52}, pmid = {35787627}, issn = {2055-5008}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Deoxyribonuclease I ; Dextrans ; *Nanoparticles ; Pseudomonas aeruginosa ; *Tobramycin/pharmacology ; }, abstract = {The extracellular matrix protects biofilm cells by reducing diffusion of antimicrobials. Tobramycin is an antibiotic used extensively to treat P. aeruginosa biofilms, but it is sequestered in the biofilm periphery by the extracellular negative charge matrix and loses its efficacy significantly. Dispersal of the biofilm extracellular matrix with enzymes such as DNase I is another promising therapy that enhances antibiotic diffusion into the biofilm. Here, we combine the charge neutralization of tobramycin provided by dextran-based single-chain polymer nanoparticles (SCPNs) together with DNase I to break the biofilm matrix. Our study demonstrates that the SCPNs improve the activity of tobramycin and DNase I by neutralizing the ionic interactions that keep this antibiotic in the biofilm periphery. Moreover, the detailed effects and interactions of nanoformulations with extracellular matrix components were revealed through time-lapse imaging of the P. aeruginosa biofilms by laser scanning confocal microscopy with specific labeling of the different biofilm components.}, } @article {pmid35786926, year = {2022}, author = {Yang, Y and Bar-Zeev, E and Oron, G and Herzberg, M and Bernstein, R}, title = {Biofilm Formation and Biofouling Development on Different Ultrafiltration Membranes by Natural Anaerobes from an Anaerobic Membrane Bioreactor.}, journal = {Environmental science & technology}, volume = {56}, number = {14}, pages = {10339-10348}, doi = {10.1021/acs.est.2c02007}, pmid = {35786926}, issn = {1520-5851}, mesh = {Anaerobiosis ; Bacteria, Anaerobic ; Biofilms ; *Biofouling ; Bioreactors ; Membranes, Artificial ; Ultrafiltration/methods ; }, abstract = {Biofouling in anaerobic membrane bioreactors (AnMBRs) has not been studied widely. Moreover, the effect of membrane surface properties on biofilm formation beyond initial deposition is controversial. We investigated biofouling with polyvinyldifluoride, polyacrylonitrile, and zwitterion-modified polyethersulfone ultrafiltration membranes having different properties during 72 h filtration using natural anaerobes isolated from AnMBR and analyzed biofilm characteristics by physicochemical and molecular techniques. A decrease in membrane performance was positively correlated with biofilm formation on polyvinyldifluoride and polyacrylonitrile membranes, and as expected, physical cleaning effectively mitigated biofilm on hydrophilic and low-roughness membranes. Surprisingly, while the biofilm on the hydrophilic and low-surface roughness zwitterion-modified membrane was significantly impaired, the impact on transmembrane pressure was the highest. This was ascribed to the formation of a soft compressible thin biofilm with high hydraulic resistance, and internal clogging and pore blocking due to high pore-size distribution. Anaerobe community analysis demonstrated some selection between the bulk and biofilm anaerobes and differences in the relative abundance of the dominant anaerobes among the membranes. However, correlation analyses revealed that all membrane properties studied affected microbial communities' composition, highlighting the system's complexity. Overall, our findings indicate that the membrane properties can affect biofilm formation and the anaerobic microbial population but not necessarily alleviate biofouling.}, } @article {pmid35786715, year = {2022}, author = {Dong, H and Zhang, W and Zhou, S and Wang, P}, title = {Programmable biofilm-cellulose hybrid platform for specific clustering of microbial catalysts with optimized cellular synergy.}, journal = {Chemical communications (Cambridge, England)}, volume = {58}, number = {59}, pages = {8222-8225}, doi = {10.1039/d2cc02473j}, pmid = {35786715}, issn = {1364-548X}, mesh = {Biofilms ; *Cellulose ; Cluster Analysis ; Escherichia coli/genetics ; *Escherichia coli Infections ; Humans ; }, abstract = {A programmable biofilm-cellulose platform is constructed to facilitate the clustering of two Escherichia coli catalysts, which is promising to achieve an efficient transformation by bringing cells into close proximity. This study also provides a unique bacteria-based method for endowing traditional materials with multiple functions via genetic engineering.}, } @article {pmid35785744, year = {2022}, author = {Guo, Y and Gao, J and Wang, Z and Cui, Y and Li, Z and Wu, Z and Zhao, Y and Li, D and Dai, H}, title = {The fate and behavior mechanism of antibiotic resistance genes and microbial communities in flocs, aerobic granular and biofilm sludge under chloroxylenol pressure.}, journal = {Journal of hazardous materials}, volume = {438}, number = {}, pages = {129465}, doi = {10.1016/j.jhazmat.2022.129465}, pmid = {35785744}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; Drug Resistance, Microbial/genetics ; *Microbiota ; Nitrification ; *Sewage/chemistry ; Xylenes ; }, abstract = {Chloroxylenol (PCMX), an antibacterial agent, has been widely detected in water environment and has toxic effects on biology and ecology. During 270 d, the influence of PCMX on the performance of three nitrification systems was investigated, including floc-based sequencing batch reactor (FSBR), aerobic granule-based SBR (AGSBR) and biofilm SBR (BSBR). The nitrification capability of three systems was inhibited by PCMX, but recovered after domestication, and PCMX made three systems realize partial nitrification for 10, 100 and 35 days, respectively. The extracellular polymeric substances of three systems increased first and then decreased with the increment of PCMX. The granular structure of AGSBR may be conducive to the enrichment of antibiotic resistance genes (ARGs), and almost all ARGs of BSBR were reduced during the addition of 5.0 mg/L PCMX. The microbial community results showed that Rhodococcus as potential degrading bacteria was continuously enriched in three systems. Piscinibacter was regarded as the potential antibiotic resistant bacteria, which was positively associated with multiple ARGs in three systems. Additionally, quaternary ammonium compounds resistance genes had a variety of positive correlations with bacteria in three systems. This study provided a new perspective for the usage and treatment of PCMX.}, } @article {pmid35783405, year = {2022}, author = {Sivaranjani, M and McCarthy, MC and Sniatynski, MK and Wu, L and Dillon, JR and Rubin, JE and White, AP}, title = {Biofilm Formation and Antimicrobial Susceptibility of E. coli Associated With Colibacillosis Outbreaks in Broiler Chickens From Saskatchewan.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {841516}, pmid = {35783405}, issn = {1664-302X}, abstract = {The global poultry industry has grown to the extent that the number of chickens now well exceeds the number of humans on Earth. Escherichia coli infections in poultry cause significant morbidity and economic losses for producers each year. We obtained 94 E. coli isolates from 12 colibacillosis outbreaks on Saskatchewan farms and screened them for antimicrobial resistance and biofilm formation. Fifty-six isolates were from broilers with confirmed colibacillosis, and 38 isolates were from healthy broilers in the same flocks (cecal E. coli). Resistance to penicillins, tetracyclines, and aminoglycosides was common in isolates from all 12 outbreaks, while cephalosporin resistance varied by outbreak. Most E. coli were able to form biofilms in at least one of three growth media (1/2 TSB, M63, and BHI broth). There was an overall trend that disease-causing E. coli had more antibiotic resistance and were more likely to form biofilms in nutrient-rich media (BHI) as compared to cecal strains. However, on an individual strain basis, there was no correlation between antimicrobial resistance and biofilm formation. The 21 strongest biofilm forming strains consisted of both disease-causing and cecal isolates that were either drug resistant or susceptible. Draft whole genome sequencing indicated that many known antimicrobial resistance genes were present on plasmids, with disease-causing E. coli having more plasmids on average than their cecal counterparts. We tested four common disinfectants for their ability to kill 12 of the best biofilm forming strains. All disinfectants killed single cells effectively, but biofilm cells were more resistant, although the difference was less pronounced for the disinfectants that have multiple modes of action. Our results indicate that there is significant diversity and complexity in E. coli poultry isolates, with different lifestyle pressures affecting disease-causing and cecal isolates.}, } @article {pmid35783396, year = {2022}, author = {Ren, Z and Yu, J and Du, J and Zhang, Y and Hamushan, M and Jiang, F and Zhang, F and Wang, B and Tang, J and Shen, H and Han, P}, title = {A General Map of Transcriptional Expression of Virulence, Metabolism, and Biofilm Formation Adaptive Changes of Staphylococcus aureus When Exposed to Different Antimicrobials.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {825041}, pmid = {35783396}, issn = {1664-302X}, abstract = {Biofilm formation of Staphylococcus aureus is the major cause of implant-associated infections (IAIs). Antimicrobial treatment is one of the most effective therapeutic options for S. aureus infections. However, it can also lead to adaptive transcriptomic changes due to extreme selective pressure, which may increase the risk of antimicrobial resistance. To study the transcriptional changes in S. aureus upon exposure to antimicrobial agents, we obtained expression profiles of S. aureus treated with six antimicrobials (flucloxacillin, vancomycin, ciprofloxacin, clindamycin, erythromycin, and linezolid, n = 6 for each group). We also included an untreated control group (n = 8) downloaded from the Gene Expression Omnibus (GEO) database (GSE70043, GSE56100) for integrated bioinformatic analyses. We identified 82 (44 up, 38 down) and 53 (17 up, 36 down) differentially expressed genes (DEGs) in logarithmic and stationary phases, respectively. When exposed to different antimicrobial agents, we found that manganese import system genes and immune response gene sbi (immunoglobulin G-binding protein Sbi) were upregulated in S. aureus at all stages. During the logarithmic phase, we observed adaptive transcriptomic changes in S. aureus mainly in the stability of protein synthesis, adhesion, and biofilm formation. In the stationary phase, we observed a downregulation in genes related to amino biosynthesis, ATP synthesis, and DNA replication. We verified these results by qPCR. Importantly, these results could help our understanding of the molecular mechanisms underlying the proliferation and antimicrobial resistance of S. aureus.}, } @article {pmid35780324, year = {2023}, author = {Yazdanpanah, S and Sasanipoor, F and Khodadadi, H and Rezaei-Matehkolaei, A and Jowkar, F and Zomorodian, K and Kharazi, M and Mohammadi, T and Nouripour-Sisakht, S and Nasr, R and Motamedi, M}, title = {Quantitative analysis of in vitro biofilm formation by clinical isolates of dermatophyte and antibiofilm activity of common antifungal drugs.}, journal = {International journal of dermatology}, volume = {62}, number = {1}, pages = {120-127}, doi = {10.1111/ijd.16337}, pmid = {35780324}, issn = {1365-4632}, support = {20040//Shiraz University of Medical Sciences/ ; }, mesh = {Humans ; Antifungal Agents/pharmacology/therapeutic use ; Terbinafine/pharmacology/therapeutic use ; *Arthrodermataceae ; Itraconazole/therapeutic use ; Griseofulvin/therapeutic use ; Microbial Sensitivity Tests ; Trichophyton ; Biofilms ; *Tinea/microbiology ; }, abstract = {BACKGROUND: The ability of dermatophytes to develop biofilm, as one of the virulence factors in fungal infections which contribute to antifungal resistance, is an outstanding aspect of dermatophytosis that has been noted recently. Because of the paucity of data about the biofilm formation by dermatophytes and their susceptibility to antifungal drugs, this study evaluated the biofilm formation by clinical isolates of dermatophytes and antibiofilm activity of common antifungals widely used to manage dermatophytosis.

METHODS: The ribosomal DNA internal transcribed spacer (ITS) regions sequencing for species identification of 50 clinical dermatophyte isolates was performed. The ability of isolates to form biofilm and inhibitory activity of itraconazole, terbinafine, and griseofulvin against biofilm formation was assayed by the crystal violet staining method. Optical microscopy and scanning electron microscopy (SEM) were applied for the visualization of the biofilm structures.

RESULTS: Trichophyton (T.) mentagrophytes (n: 14; 28%) and T. rubrum (n: 13;26%) were included in more than half of the dermatophyte isolates. Biofilm formation was observed in 37 out of 50 (74%) isolates that were classified as follows: nonproducers (n: 13; 26%), weak producers (n: 4; 8%), moderate producers (n: 16; 32%), and strong producers (n: 17; 34%) by comparison of the absorbance of biofilms produced by clinical strains with control. The mean IC50 values for terbinafine, griseofulvin, and itraconazole were 2.42, 3.18, and 3.78 μg/ml, respectively.

CONCLUSIONS: The results demonstrated that most of the clinical dermatophyte isolates are capable to form biofilm in vitro with variable strength. Moreover, terbinafine can be suggested as the first-line choice for the treatment of biofilm-formed dermatophytosis.}, } @article {pmid35780192, year = {2022}, author = {Borsanelli, AC and Athayde, FRF and Saraiva, JR and Riggio, MP and Dutra, IS}, title = {Dysbiosis and Predicted Functions of the Dental Biofilm of Dairy Goats with Periodontitis.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, pmid = {35780192}, issn = {1432-184X}, support = {4-299//United States Agency for International Development/ ; }, abstract = {Periodontitis is a polymicrobial biofilm-induced inflammatory disease associated with a dysbiotic microbial community and severely affects the health and welfare of animals. However, little is known regarding the dental microbiota associated with this disease in goats. In this study, we used high-throughput sequencing, network analysis, and predicted functions to investigate the microbiota of clinically healthy goats and those with periodontitis and identify possible pathogens and proteins associated with the disease. Dental microbiomes of goats with periodontitis were richer, and network analyses showed that the number of negative interactions was higher in the networks of animals with periodontitis. Based on the interrelationships, Porphyromonas, Fusobacterium, and Prevotella were suggested to play an important role in the dental microbiota associated with goat periodontitis. Protein families linked to translation, cytoplasmatic translation, and rRNA processing were more abundant in the dental microbiota of goats with periodontitis. In conclusion, the dental biofilm microbiota associated with goat periodontitis seems to be dysbiotic and has significant antagonistic interactions, which discriminate healthy animals from diseased animals and highlight the importance of key bacteria. Thus, these novel findings contribute to the evolution of knowledge regarding the etiopathogenesis of goat periodontitis and possibly to the development of periodontitis control measures.}, } @article {pmid35780174, year = {2022}, author = {Vaziriamjad, S and Solgi, M and Kamarehei, F and Nouri, F and Taheri, M}, title = {Evaluation of L-arginine supplement on the growth rate, biofilm formation, and antibiotic susceptibility in Streptococcus mutans.}, journal = {European journal of medical research}, volume = {27}, number = {1}, pages = {108}, pmid = {35780174}, issn = {2047-783X}, support = {9910167290//Hamadan University of Medical Sciences/ ; 9910167290//Hamadan University of Medical Sciences/ ; 9910167290//Hamadan University of Medical Sciences/ ; 9910167290//Hamadan University of Medical Sciences/ ; 9910167290//Hamadan University of Medical Sciences/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Arginine/metabolism/pharmacology ; Biofilms ; *Dental Caries/prevention & control ; Humans ; *Streptococcus mutans/metabolism ; }, abstract = {INTRODUCTION: Bacteria associated with dental caries have a high ability to produce organic acids from dietary carbohydrates during growth and metabolism under acidic conditions. In contrast, many symbiotic bacteria produce ammonia through the arginine deiminase (ADS) system, which modulates the pH of the oral cavity. L-Arginine metabolism by ADS is a significant inhibitor in the progression of tooth decay. This study aimed to investigate the effect of L-arginine on growth, biofilm formation, and antibiotic susceptibility in Streptococcus mutans.

METHODS: In this study, the effect of L-arginine in different concentrations on the growth rate, antibiotic susceptibility, and inhibition of biofilm formation in S. mutans was investigated.

RESULTS: The bacterial exponential growth rate was enhanced by 100 μM L-arginine (P > 0.05). The growth inhibition zone diameter of CAZ, CTR, AMP, and AMC-Clav antibiotics was reduced after 24 h of exposure in the presence of various concentrations of L-arginine specifically at 100 μM. L-Arginine also enhanced biofilm development at 5 and 10 μM concentrations, but reduced it at 50 and 100 μM concentrations.

CONCLUSION: According to the results of the present study, optimization of L-arginine concentration and its use as an adjunctive therapy or in combination with mouthwash or varnish is recommended to prevent oral caries.}, } @article {pmid35779720, year = {2022}, author = {Wang, HB and Wu, YH and Wang, WL and Chen, Z and Chen, GQ and Luo, LW and Xue, S and Tong, X and Zhang, ZW and Ikuno, N and Ishii, K and Hu, HY}, title = {Comparison of disinfection-residual-bacteria (DRB) after seven different kinds of disinfection: Biofilm formation, membrane fouling and mechanisms.}, journal = {The Science of the total environment}, volume = {844}, number = {}, pages = {157079}, doi = {10.1016/j.scitotenv.2022.157079}, pmid = {35779720}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; *Biofouling/prevention & control ; Disinfection ; Extracellular Polymeric Substance Matrix ; Membranes, Artificial ; Osmosis ; *Water Purification/methods ; }, abstract = {Membrane fouling is the Achilles' heel of the reverse osmosis (RO) system for high-quality reclaimed water production. Previous studies have found that after the significant selection effect of traditional disinfection, the remaining disinfection-residual bacteria (DRB) may possess more severe biofouling potentials. To provide more constructive advice for the prevention of biofouling, we compared the RO membrane fouling characteristics of DRB after using five commonly used disinfection methods (NaClO, NH2Cl, ClO2, UV, and O3) and two novel disinfection methods (K2FeO4 and the flow-through electrode system (FES)). Compared with the control group (undisinfected, 21.1 % flux drop), the UV-DRB biofilm aggravated biofouling of the RO membrane (23.4 % flux drop), while the FES, K2FeO4, and NH2Cl treatments showed less severe biofouling, with final flux drops of 6.9 %, 8.1 %, and 8.1 %, respectively. Adenosine triphosphate (ATP) was found to be a capable indicator for predicting the biofouling potential of DRB. Systematic analysis showed that the thickness and density of the DRB biofilms were most closely related to the different fouling degree of RO membranes. Moreover, the relative abundance of bacteria with higher extracellular polymeric substance (EPS) secretion levels, such as Pseudomonas and Sphingomonas, was found closely related with the biofouling degree of RO membranes.}, } @article {pmid35779259, year = {2022}, author = {Mourer, T and Sachse, M and Gazi, AD and d'Enfert, C and Bachellier-Bassi, S}, title = {A protocol for ultrastructural study of Candida albicans biofilm using transmission electron microscopy.}, journal = {STAR protocols}, volume = {3}, number = {3}, pages = {101514}, pmid = {35779259}, issn = {2666-1667}, mesh = {*Biofilms ; *Candida albicans/ultrastructure ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Plastics ; }, abstract = {This protocol describes how to analyze C. albicans biofilm using transmission electron microscopy. We present two approaches to observe the ultrastructure of fungal cells within unperturbed biofilms, as well as an immunogold labeling procedure. This approach maintains the architecture of the fungal biofilm close to its native state by growing C. albicans biofilm on a plastic surface. After the freeze substitution procedure, classical transmission electron microscopy or electron tomography will allow the ultrastructural analysis of the microbial community.}, } @article {pmid35777514, year = {2022}, author = {Ge, Z and Chen, X and Yang, R and Li, W and Yin, B and Li, Z and Dong, M}, title = {Structure of a unique fucose-containing exopolysaccharide from Sayram ketteki yoghurt and its anti-MRSA biofilm effect.}, journal = {International journal of biological macromolecules}, volume = {216}, number = {}, pages = {643-654}, doi = {10.1016/j.ijbiomac.2022.06.164}, pmid = {35777514}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Fucose/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Spectroscopy, Fourier Transform Infrared ; Yogurt ; }, abstract = {In this work, we reported an in situ exopolysaccharide (in situ-EPS1) containing rare fucose produced by Lactobacillus helveticus MB2-1 in Sayram ketteki yoghurt, which made it unique. Its fine structure was characterized by GPC, HPLC, FT-IR, GC-MS,[1]HNMR and [13]CNMR together with two-dimensional (2D) NMR spectra. The results revealed that in situ-EPS1 was a new heteropolysaccharide with molecular weight of 1.06 × 10[5] Da, and was composed of mannose, rhamnose, glucose, galactose and fucose with the following repeating units. Furthermore, the in situ-EPS1 exhibited significant antibiofilm effect against Methicillin-resistant Staphylococcus aureus (MRSA). Notably, the in situ-EPS1 did not interfere with the planktonic growth of MRSA strain, whereas inhibited its cell metabolic activity and the transcription of genes related to biofilm formation. This unique antibiofilm but non-antibacterial mechanism supposedly prevented the development of bacterial drug resistance, which may open a new door to fight against these drug-resistant microorganisms.}, } @article {pmid35777467, year = {2022}, author = {Yarawsky, AE and Hopkins, JB and Chatzimagas, L and Hub, JS and Herr, AB}, title = {Solution Structural Studies of Pre-amyloid Oligomer States of the Biofilm Protein Aap.}, journal = {Journal of molecular biology}, volume = {434}, number = {16}, pages = {167708}, pmid = {35777467}, issn = {1089-8638}, support = {P30 GM138395/GM/NIGMS NIH HHS/United States ; P41 GM103622/GM/NIGMS NIH HHS/United States ; R01 GM094363/GM/NIGMS NIH HHS/United States ; S10 OD018090/OD/NIH HHS/United States ; }, mesh = {*Amyloid/chemistry/genetics ; *Bacterial Proteins/chemistry/genetics ; *Biofilms ; Humans ; Models, Chemical ; Mutation ; Protein Multimerization ; Scattering, Small Angle ; *Staphylococcus epidermidis/physiology ; X-Ray Diffraction ; }, abstract = {Staphylococcus epidermidis is a commensal bacterium on human skin that is also the leading cause of medical device-related infections. The accumulation-associated protein (Aap) from S. epidermidis is a critical factor for infection via its ability to mediate biofilm formation. The B-repeat superdomain of Aap is composed of 5 to 17 Zn[2+]-binding B-repeats, which undergo rapid, reversible assembly to form dimer and tetramer species. The tetramer can then undergo a conformational change and nucleate highly stable functional amyloid fibrils. In this study, multiple techniques including analytical ultracentrifugation (AUC) and small-angle X-ray scattering (SAXS) are used to probe a panel of B-repeat mutant constructs that assemble to distinct oligomeric states to define the structural characteristics of B-repeat dimer and tetramer species. The B-repeat region from Aap forms an extremely elongated conformation that presents several challenges for standard SAXS analyses. Specialized approaches, such as cross-sectional analyses, allowed for in-depth interpretation of data, while explicit-solvent calculations via WAXSiS allowed for accurate evaluation of atomistic models. The resulting models suggest mechanisms by which Aap functional amyloid fibrils form, illuminating an important contributing factor to recurrent staphylococcal infections.}, } @article {pmid35777177, year = {2022}, author = {Besser, M and Schaeler, L and Plattfaut, I and Brill, FHH and Kampe, A and Geffken, M and Smeets, R and Debus, ES and Stuermer, EK}, title = {Pulsed low-intensity laser treatment stimulates wound healing without enhancing biofilm development in vitro.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {233}, number = {}, pages = {112504}, doi = {10.1016/j.jphotobiol.2022.112504}, pmid = {35777177}, issn = {1873-2682}, mesh = {*Anti-Infective Agents ; Bacteria ; Biofilms ; *Endothelial Cells ; Humans ; Lasers ; Wound Healing ; }, abstract = {OBJECTIVES: Treating infected or chronic wounds burdened with biofilms still is a major challenge in medical care. Healing-stimulating factors lose their efficacy due to bacterial degradation, and antimicrobial substances negatively affect dermal cells. Therefore, alternative treatment approaches like the pulsed low intensity laser therapy (LILT) require consideration.

METHODS: The effect of pulsed LILT (904 nm, in three frequencies) on relevant human cells of the wound healing process (fibroblasts (BJ), keratinocytes (HaCaT), endothelial cells (HMEC), monocytes (THP-1)) were investigated in in-vitro and ex-vivo wound models with respect to viability, proliferation and migration. Antimicrobial efficacy of the most efficient frequency in cell biological analyses of LILT (3200 Hz) was determined in a human biofilm model (lhBIOM). Quantification of bacterial load was evaluated by suspension method and qualitative visualization was performed by scanning electron microscopy (SEM).

RESULTS: Pulsed LILT at 904 nm at 3200 Hz ± 50% showed the most positive effects on metabolic activity and proliferation of human wound cells in vitro (after 72 h - BJ: BPT 0.97 ± 0.05 vs. 0.75 ± 0.04 (p = 0.0283); HaCaT: BPT 0.79 ± 0.04 vs. 0.59 ± 0.02 (p = 0.0106); HMEC: 0.74 ± 0.02 vs. 0.52 ± 0.04 (p = 0.009); THP-1: 0.58 ± 0.01 vs. 0.64 ± 0.01 (p > 0.05) and ex vivo. Interestingly, re-epithelialization was stimulated in a frequency-independent manner. The inhibition of metabolic activity after TNF-α application was abolished after laser treatment. No impact of LILT on monocytes was detected. Likewise, the tested LILT regimens showed no growth rate reducing effects on three bacterial strains (after 72 h - PA: -1.03%; SA: -0.02%; EF: -1,89%) and one fungal (-2.06%) biofilm producing species compared to the respective untreated control. Accordingly, no significant morphological changes of the biofilms were observed after LILT treatment in the SEM.

CONCLUSIONS: Frequent application of LILT (904 nm, 3200 Hz) seems to be beneficial for the metabolism of human dermal cells during wound healing. Considering this, the lack of disturbance of the behavior of the immune cells and no growth-inducing effect on bacteria and fungi in the biofilm can be assigned as rather positive. Based on this combined mode of action, LILT may be an option for hard to heal wounds infected with persistent biofilms.}, } @article {pmid35776759, year = {2022}, author = {Moshynets, OV and Baranovskyi, TP and Cameron, S and Iungin, OS and Pokholenko, I and Jerdan, R and Kamyshnyi, A and Krikunov, AA and Potochilova, VV and Rudnieva, KL and Spiers, AJ}, title = {Azithromycin possesses biofilm-inhibitory activity and potentiates non-bactericidal colistin methanesulfonate (CMS) and polymyxin B against Klebsiella pneumonia.}, journal = {PloS one}, volume = {17}, number = {7}, pages = {e0270983}, pmid = {35776759}, issn = {1932-6203}, support = {/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Azithromycin/pharmacology/therapeutic use ; Biofilms ; Colistin/pharmacology/therapeutic use ; Humans ; *Klebsiella Infections/microbiology ; Klebsiella pneumoniae ; Mesylates ; Microbial Sensitivity Tests ; *Pneumonia/drug therapy ; Polymyxin B/pharmacology/therapeutic use ; }, abstract = {Novel antibiotic combinations may act synergistically to inhibit the growth of multidrug-resistant bacterial pathogens but predicting which combination will be successful is difficult, and standard antimicrobial susceptibility testing may not identify important physiological differences between planktonic free-swimming and biofilm-protected surface-attached sessile cells. Using a nominally macrolide-resistant model Klebsiella pneumoniae strain (ATCC 10031) we demonstrate the effectiveness of several macrolides in inhibiting biofilm growth in multi-well plates, and the ability of azithromycin (AZM) to improve the effectiveness of the antibacterial last-agent-of-choice for K. pneumoniae infections, colistin methanesulfonate (CMS), against biofilms. This synergistic action was also seen in biofilm tests of several K. pneumoniae hospital isolates and could also be identified in polymyxin B disc-diffusion assays on azithromycin plates. Our work highlights the complexity of antimicrobial-resistance in bacterial pathogens and the need to test antibiotics with biofilm models where potential synergies might provide new therapeutic opportunities not seen in liquid culture or colony-based assays.}, } @article {pmid35775548, year = {2022}, author = {Sharma, A and Vashistt, J and Shrivastava, R}, title = {Knockdown of the Type-II Fatty acid synthase gene hadC in mycobacterium fortuitum does not affect its growth, biofilm formation, and survival under stress.}, journal = {International journal of mycobacteriology}, volume = {11}, number = {2}, pages = {159-166}, doi = {10.4103/ijmy.ijmy_46_22}, pmid = {35775548}, issn = {2212-554X}, mesh = {Biofilms ; Detergents ; Fatty Acid Synthases/genetics ; Gentian Violet ; Humans ; *Mycobacterium fortuitum/genetics ; *Mycobacterium tuberculosis/genetics ; }, abstract = {BACKGROUND: Mycobacterial fatty acid synthase Type-II (FAS-II) components are major virulence factors exploited as potential targets for developing novel antimycobacterial drugs. The FAS-II enzyme 3-hydroxyacyl-ACP dehydratase (HadC) is important for biofilm development and pathogenesis of Mycobacterium tuberculosis and other mycobacterial species.

METHODS: Literature review and homology search led to the identification of Mycobacterium fortuitum MFhadC gene. Functional interaction study of MFHadC protein was done using STRING. M. fortuitum MFhadC over-expressing (HS) and knockdown (HA) strains were constructed and validated by expression analysis using quantitative polymerase chain reaction. The strains were analyzed for growth behavior and surface spreading ability. Biofilm formation was assayed through crystal violet assay, viability count, and basic fuchsin staining. In addition, survival of the strains was studied under in vitro nutrient starvation and detergent stress.

RESULTS: STRING analysis showed the interaction of HadC with proteins involved in biofilm formation. The strains HS and HA showed spreading ability on the agarose surface, exhibiting translocation patterns similar to the vector control strain. All three strains showed a similar amount of biofilm formation when analyzed using crystal violet assay, viability count, and basic fuchsin staining. The strains showed no deviation in survival when incubated under nutrient starvation and detergent stress.

CONCLUSION: Our results suggest that MFhadC may not be important for the formation and maintenance of biofilm, a factor critically important in M. fortuitum pathogenicity. However, not essential for survival and growth, MFhadC maintains the viability of M. fortuitum under a nutrient-starved environment. Collectively, MFhadC may not be used as a biofilm-specific marker for M. fortuitum.}, } @article {pmid35774452, year = {2022}, author = {Tao, Q and Wu, Q and Zhang, Z and Liu, J and Tian, C and Huang, Z and Malakar, PK and Pan, Y and Zhao, Y}, title = {Meta-Analysis for the Global Prevalence of Foodborne Pathogens Exhibiting Antibiotic Resistance and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {906490}, pmid = {35774452}, issn = {1664-302X}, abstract = {Antimicrobial-resistant (AMR) foodborne bacteria causing bacterial infections pose a serious threat to human health. In addition, the ability of some of these bacteria to form biofilms increases the threat level as treatment options may become compromised. The extent of antibiotic resistance and biofilm formation among foodborne pathogens remain uncertain globally due to the lack of systematic reviews. We performed a meta-analysis on the global prevalence of foodborne pathogens exhibiting antibiotic resistance and biofilm formation using the methodology of a Cochrane review by accessing data from the China National Knowledge Infrastructure (CNKI), PubMed, and Web of Science databases between 2010 and 2020. A random effects model of dichotomous variables consisting of antibiotic class, sample source, and foodborne pathogens was completed using data from 332 studies in 36 countries. The results indicated AMR foodborne pathogens has become a worrisome global issue. The prevalence of AMR foodborne pathogens in food samples was greater than 10% and these foodborne pathogens were most resistant to β-lactamase antibiotics with Bacillus cereus being most resistant (94%). The prevalence of AMR foodborne pathogens in human clinical specimens was greater than 19%, and the resistance of these pathogens to the antibiotic class used in this research was high. Independently, the overall biofilm formation rate of foodborne pathogenic bacteria was 90% (95% CI, 68%-96%) and a direct linear relationship between biofilm formation ability and antibiotic resistance was not established. Future investigations should document both AMR and biofilm formation of the foodborne pathogen isolated in samples. The additional information could lead to alternative strategies to reduce the burden cause by AMR foodborne pathogens.}, } @article {pmid35774451, year = {2022}, author = {Wu, S and Wu, B and Liu, Y and Deng, S and Lei, L and Zhang, H}, title = {Mini Review Therapeutic Strategies Targeting for Biofilm and Bone Infections.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {936285}, pmid = {35774451}, issn = {1664-302X}, abstract = {Bone infection results in a complex inflammatory response and bone destruction. A broad spectrum of bacterial species has been involved for jaw osteomyelitis, hematogenous osteomyelitis, vertebral osteomyelitis or diabetes mellitus, such as Staphylococcus aureus (S. aureus), coagulase-negative Staphylococcus species, and aerobic gram-negative bacilli. S. aureus is the major pathogenic bacterium for osteomyelitis, which results in a complex inflammatory response and bone destruction. Although various antibiotics have been applied for bone infection, the emergence of drug resistance and biofilm formation significantly decrease the effectiveness of those agents. In combination with gram-positive aerobes, gram-negative aerobes and anaerobes functionally equivalent pathogroups interact synergistically, developing as pathogenic biofilms and causing recurrent infections. The adhesion of biofilms to bone promotes bone destruction and protects bacteria from antimicrobial agent stress and host immune system infiltration. Moreover, bone is characterized by low permeability and reduced blood flow, further hindering the therapeutic effect for bone infections. To minimize systemic toxicity and enhance antibacterial effectiveness, therapeutic strategies targeting on biofilm and bone infection can serve as a promising modality. Herein, we focus on biofilm and bone infection eradication with targeting therapeutic strategies. We summarize recent targeting moieties on biofilm and bone infection with peptide-, nucleic acid-, bacteriophage-, CaP- and turnover homeostasis-based strategies. The antibacterial and antibiofilm mechanisms of those therapeutic strategies include increasing antibacterial agents' accumulation by bone specific affinity, specific recognition of phage-bacteria, inhibition biofilm formation in transcription level. As chronic inflammation induced by infection can trigger osteoclast activation and inhibit osteoblast functioning, we additionally expand the potential applications of turnover homeostasis-based therapeutic strategies on biofilm or infection related immunity homeostasis for host-bacteria. Based on this review, we expect to provide useful insights of targeting therapeutic efficacy for biofilm and bone infection eradication.}, } @article {pmid35771939, year = {2022}, author = {Tai, JB and Mukherjee, S and Nero, T and Olson, R and Tithof, J and Nadell, CD and Yan, J}, title = {Social evolution of shared biofilm matrix components.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {27}, pages = {e2123469119}, pmid = {35771939}, issn = {1091-6490}, support = {DP2 GM146253/GM/NIGMS NIH HHS/United States ; }, mesh = {*Bacteria/growth & development ; *Extracellular Polymeric Substance Matrix ; Models, Biological ; *Social Evolution ; Vibrio cholerae ; }, abstract = {Biofilm formation is an important and ubiquitous mode of growth among bacteria. Central to the evolutionary advantage of biofilm formation is cell-cell and cell-surface adhesion achieved by a variety of factors, some of which are diffusible compounds that may operate as classical public goods-factors that are costly to produce but may benefit other cells. An outstanding question is how diffusible matrix production, in general, can be stable over evolutionary timescales. In this work, using Vibrio cholerae as a model, we show that shared diffusible biofilm matrix proteins are indeed susceptible to cheater exploitation and that the evolutionary stability of producing these matrix components fundamentally depends on biofilm spatial structure, intrinsic sharing mechanisms of these components, and flow conditions in the environment. We further show that exploitation of diffusible adhesion proteins is localized within a well-defined spatial range around cell clusters that produce them. Based on this exploitation range and the spatial distribution of cell clusters, we constructed a model of costly diffusible matrix production and related these length scales to the relatedness coefficient in social evolution theory. Our results show that production of diffusible biofilm matrix components is evolutionarily stable under conditions consistent with natural biofilm habitats and host environments. We expect the mechanisms revealed in this study to be relevant to other secreted factors that operate as cooperative public goods in bacterial communities and the concept of exploitation range and the associated analysis tools to be generally applicable.}, } @article {pmid35771053, year = {2022}, author = {Kamei, T and Rujakom, S and Nakano, M and Maharjan, AK and Kazama, F}, title = {Investigation of nitrite accumulation by hydrogenotrophic denitrification in a moving bed biofilm reactor for partial denitrification and anammox process.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {85}, number = {12}, pages = {3396-3407}, doi = {10.2166/wst.2022.187}, pmid = {35771053}, issn = {0273-1223}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; *Denitrification ; *Nitrites ; Nitrogen ; Nitrogen Dioxide ; Oxidation-Reduction ; Sewage ; Wastewater/microbiology ; }, abstract = {The partial denitrification and anammox (PDA) process has received attention for its ability to optimize treatment of wastewater containing a low NH4[+]-N concentration. This study investigated the suitable operational conditions for NO2[-]-N accumulation by hydrogenotrophic denitrification (HD) in operation of a laboratory-scale moving bed biofilm reactor, for future application in the PDA process. NO2[-]-N accumulation was achieved by minimizing the H2 flow rate under optimized conditions (i.e., 15 mL/min H2 flow rate, 40 mg-N/L influent NO3[-]-N, 7.0 h hydraulic retention time, and 2 L working volume). Hydrogenophaga comprised 39.2% of the bacterial abundance after NO2[-]-N accumulated, indicating its contribution to the NO2[-]-N accumulation. In addition, an intermittent H2 supply maintained the NO2[-]-N accumulation rate (NAR) and maximized the nitrite accumulation efficiency (NAE). A H2 supply ratio of 0.7 (i.e., ON: 7 min, OFF: 3 min) was optimal, which induced increases in NAR, NAE, and the NO3[-]-N removal efficiency that reached 0.07±0.01 kg-N/m[3]/d, 64.4±14.5%, and 89.2±8.9%, respectively. The ratio of H2 supply rate to the NO3[-]-N loading rate was calculated as 4.3 in this experiment, which may represent the optimal balance for maximization of NO2[-]-N accumulation by HD.}, } @article {pmid35770177, year = {2022}, author = {Niboucha, N and Goetz, C and Sanschagrin, L and Fontenille, J and Fliss, I and Labrie, S and Jean, J}, title = {Comparative Study of Different Sampling Methods of Biofilm Formed on Stainless-Steel Surfaces in a CDC Biofilm Reactor.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {892181}, pmid = {35770177}, issn = {1664-302X}, abstract = {The formation of biofilms in dairy processing plants can reduce equipment efficiency, contribute to surface deterioration, and contaminate dairy products by releasing the microorganisms they contain, which may cause spoilage or disease. However, a more representative identification of microbial communities and physico-chemical characterization requires to detach and recover adequately the entire biofilm from the surface. The aim of this study is to develop an efficient technique for in-plant biofilm sampling by growing a strain of Pseudomonas azotoformans PFl1A on stainless-steel surface in a dynamic CDC biofilm reactor system using tryptic soy broth (TSB) and milk as growth media. Different techniques, namely, swabbing, scraping, sonic brushing, synthetic sponge, and sonicating synthetic sponge were used and the results were compared to a standard ASTM International method using ultrasonication. Their efficiencies were evaluated by cells enumeration and scanning electron microscopy. The maximum total viable counts of 8.65 ± 0.06, 8.75 ± 0.08, and 8.71 ± 0.09 log CFU/cm[2] were obtained in TSB medium using scraping, synthetic sponge, and sonicating synthetic sponge, respectively, which showed no statistically significant differences with the standard method, ultrasonication (8.74 ± 0.02 log CFU/cm[2]). However, a significantly (p < 0.05) lower cell recovery of 8.57 ± 0.10 and 8.60 ± 0.00 log CFU/cm[2] compared to ultrasonication were achieved for swabbing and sonic brushing, respectively. Furthermore, scanning electron microscopy showed an effective removal of biofilms by sonic brushing, synthetic sponge, and sonicating synthetic sponge; However, only the latter two methods guaranteed a superior release of bacterial biofilm into suspension. Nevertheless, a combination of sonication and synthetic sponge ensured dislodging of sessile cells from surface crevices. The results suggest that a sonicating synthetic sponge could be a promising method for biofilm recovery in processing plants, which can be practically used in the dairy industries as an alternative to ultrasonication.}, } @article {pmid35769516, year = {2022}, author = {Dong, H and Yang, K and Zhang, Y and Li, Q and Xiu, W and Ding, M and Shan, J and Mou, Y}, title = {Photocatalytic Cu2WS4 Nanocrystals for Efficient Bacterial Killing and Biofilm Disruption.}, journal = {International journal of nanomedicine}, volume = {17}, number = {}, pages = {2735-2750}, pmid = {35769516}, issn = {1178-2013}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Hydrogen Peroxide/pharmacology ; Mice ; *Nanoparticles ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus ; *Wound Infection/microbiology ; }, abstract = {BACKGROUND: Bacterial biofilm-related wound infections threaten human health due to the lack of efficient treatments. Therefore, developing a novel strategy for wound infection care is urgently needed.

METHODS: Cube-shaped Cu2WS4 nanocrystals (CWSNs) were successfully prepared via a microwave-assisted method. CWSNs, as photocatalysts, were first studied by using fluorescence spectroscopy for their ability to generate reactive oxygen species (ROS). The antibacterial and biofilm inhibition abilities of CWSNs were determined in vitro by using Staphylococcus aureus (S. aureus) as the model bacterium. Moreover, a CWSN gel was prepared and applied to treat S. aureus-infected wounds in mice. The toxicity of the CWSNs was evaluated through in vitro cell and in vivo animal experiments.

RESULTS: Studies on the properties of the CWSNs demonstrated that these nanomaterials can catalyze the generation of hydroxyl radicals (•OH) without the addition of H2O2 after visible-light irradiation, indicating their photocatalytic ability. Moreover, the in vitro experimental results showed that the CWSNs not only adhered to the surfaces of S. aureus to kill the bacteria, but also inhibited S. aureus biofilm formation. The in vivo study showed that the CWSN gel produced excellent antibacterial effects against S. aureus infected wounds in mice and effectively promoted wound healing. Furthermore, toxicity tests showed that the CWSNs have negligible toxicity in vitro and in vivo.

CONCLUSION: This work provides a potential photocatalytic antibacterial nanoagent for efficient bacterial killing, inhibition of biofilms growth and wound infection treatment.}, } @article {pmid35769322, year = {2022}, author = {Jiang, L and Jiang, Y and Liu, W and Zheng, R and Li, C}, title = {Characterization of the Lytic Phage Flora With a Broad Host Range Against Multidrug-Resistant Escherichia coli and Evaluation of Its Efficacy Against E. coli Biofilm Formation.}, journal = {Frontiers in veterinary science}, volume = {9}, number = {}, pages = {906973}, pmid = {35769322}, issn = {2297-1769}, abstract = {Escherichia coli is a gram-negative bacterium that is distributed widely throughout the world; it is mainly found in contaminated food, the poultry industry, and animal feces. The emergence of antibiotic-resistant E. coli poses a threat to human and animal health, which has led to renewed interest in phage-based therapy. E. coli biofilm control and prevention are of great importance. In this study, the isolated phages Flora and KM18 were found to belong to the family Myoviridae; the optimal preservation buffer was pH = 6~7, and the phage genome sizes were 168,909 (Flora) and 168,903 (KM18) bp. Phage Flora had a broader lytic spectrum than KM18. Phage Flora had a better antibiofilm effect than kanamycin sulfate in high-concentration E. coli cultures. A combination of the phage Flora and kanamycin sulfate showed better antibiofilm effects than Flora or kanamycin sulfate alone in low-concentration E. coli cultures. These characteristics can serve as a guideline for the selection of effective candidates for phage therapy, in this case antibiotic-resistant E. coli control in the poultry industry.}, } @article {pmid35767197, year = {2022}, author = {Chen, H and Wu, L and Su, Y and Huang, Z and Wang, L and Xia, Z and Huang, H and Wang, W and Fang, J and Gu, Z and Sun, P and Zheng, J}, title = {Inhibitory Effects of Compounds from Plumula nelumbinis on Biofilm and Quorum Sensing Against P. aeruginosa.}, journal = {Current microbiology}, volume = {79}, number = {8}, pages = {236}, pmid = {35767197}, issn = {1432-0991}, support = {81773593//national natural science foundation of china/ ; 81872759//national natural science foundation of china/ ; 82073977//national natural science foundation of china/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Molecular Docking Simulation ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors/genetics ; }, abstract = {Quorum sensing (QS), which controls the survival and virulence of Pseudomonas aeruginosa, including the formation of biofilm, is considered to be a new target to overcome pathogens. The aim of this study was to identify new QS inhibitors against P. aeruginosa and provide potential treatments for clinical infections. In this study, 25 compounds were isolated from Plumula nelumbini. Among these compounds, C25 showed the most significant biofilm inhibition activity, reaching 44.63% at 100 μM without inhibiting bacterial growth. Furthermore, C25 showed significant inhibition activity of rhamnolipid, pyocyanin, and elastase. Further mechanistic studies have confirmed that C25 could downregulate key genes in the QS system, including lasI, lasR, lasA, lasB, and pqsR, and Molecular docking studies have shown that C25 can bind to the active sites of the LasR and PqsR receptors. The present study suggests that C25 is a promising QS inhibitor for treating P. aeruginosa infections.}, } @article {pmid35764312, year = {2022}, author = {Oh, MJ and Babeer, A and Liu, Y and Ren, Z and Wu, J and Issadore, DA and Stebe, KJ and Lee, D and Steager, E and Koo, H}, title = {Surface Topography-Adaptive Robotic Superstructures for Biofilm Removal and Pathogen Detection on Human Teeth.}, journal = {ACS nano}, volume = {16}, number = {8}, pages = {11998-12012}, pmid = {35764312}, issn = {1936-086X}, support = {R01 DE025848/DE/NIDCR NIH HHS/United States ; R56 DE029985/DE/NIDCR NIH HHS/United States ; R90 DE031532/DE/NIDCR NIH HHS/United States ; }, mesh = {Humans ; *Robotic Surgical Procedures ; Biofilms ; *Tooth ; Anti-Bacterial Agents ; *Nanoparticles/chemistry ; }, abstract = {The eradication of biofilms remains an unresolved challenge across disciplines. Furthermore, in biomedicine, the sampling of spatially heterogeneous biofilms is crucial for accurate pathogen detection and precise treatment of infection. However, current approaches are incapable of removing highly adhesive biostructures from topographically complex surfaces. To meet these needs, we demonstrate magnetic field-directed assembly of nanoparticles into surface topography-adaptive robotic superstructures (STARS) for precision-guided biofilm removal and diagnostic sampling. These structures extend or retract at multilength scales (micro-to-centimeter) to operate on opposing surfaces and rapidly adjust their shape, length, and stiffness to adapt and apply high-shear stress. STARS conform to complex surface topographies by entering angled grooves or extending into narrow crevices and "scrub" adherent biofilm with multiaxis motion while producing antibacterial reagents on-site. Furthermore, as the superstructure disrupts the biofilm, it captures bacterial, fungal, viral, and matrix components, allowing sample retrieval for multiplexed diagnostic analysis. We apply STARS using automated motion patterns to target complex three-dimensional geometries of ex vivo human teeth to retrieve biofilm samples with microscale precision, while providing "toothbrushing-like" and "flossing-like" action with antibacterial activity in real-time to achieve mechanochemical removal and multikingdom pathogen detection. This approach could lead to autonomous, multifunctional antibiofilm platforms to advance current oral care modalities and other fields contending with harmful biofilms on hard-to-reach surfaces.}, } @article {pmid35764280, year = {2022}, author = {Cao, L and Li, Y and Li, P and Zhang, X and Ni, L and Qi, L and Wen, H and Zhang, X and Zhang, Y}, title = {Application of moving bed biofilm reactor - nanofiltration - membrane bioreactor with loose nanofiltration hollow fiber membranes for synthetic roxithromycin-containing wastewater treatment: Long-term performance, membrane fouling and microbial community.}, journal = {Bioresource technology}, volume = {360}, number = {}, pages = {127527}, doi = {10.1016/j.biortech.2022.127527}, pmid = {35764280}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Membranes, Artificial ; *Microbiota ; *Roxithromycin ; Wastewater ; }, abstract = {The present study operated the novel moving bed biofilm reactor-nanofiltration-membrane bioreactor (MBBR-NF-MBR) with loose polyamide NF membranes for the first time to treat roxithromycin (ROX) wastewater. Results showed that both MBBR-NF-MBRs achieved superior COD removal of 98.4% and 97.2% and excellent removal of ROX at 74.1% and 65.5%, respectively. The main membrane fouling mechanism was reversible fouling caused by the combination of abundant polysaccharides, proteins and Ca-P precipitates, which could be effectively removed by acidic cleaning. Sorption and biodegradation were the main removal routes of ROX in MBBR. Partial retention of loose NF membrane contributed to microbial metabolism and increased microbial diversity, especially the genera Hyphomicrobium in attached biofilm, which was reasonable for ROX removal. The cleavage of cladinose, demethylation, phosphorylation and β-oxidation in macrolactone ring were the main biotransformation reactions of ROX. This study provides novel insights for micropollutants wastewater treatment by using loose NF membrane in MBR.}, } @article {pmid35762651, year = {2022}, author = {Yao, S and Hao, L and Zhou, R and Jin, Y and Huang, J and Wu, C}, title = {Multispecies biofilms in fermentation: Biofilm formation, microbial interactions, and communication.}, journal = {Comprehensive reviews in food science and food safety}, volume = {21}, number = {4}, pages = {3346-3375}, doi = {10.1111/1541-4337.12991}, pmid = {35762651}, issn = {1541-4337}, mesh = {Bacteria ; *Biofilms ; Communication ; Fermentation ; *Microbial Interactions ; }, abstract = {Food fermentation is driven by microorganisms, which usually coexist as multispecies biofilms. The activities and interactions of functional microorganisms and pathogenic bacteria in biofilms have important implications for the quality and safety of fermented foods. It was verified that the biofilm lifestyle benefited the fitness of microorganisms in harsh environments and intensified the cooperation and competition between biofilm members. This review focuses on multispecies biofilm formation, microbial interactions and communication in biofilms, and the application of multispecies biofilms in food fermentation. Microbial aggregation and adhesion are important steps in the early stage of multispecies biofilm formation. Different biofilm-forming abilities and strategies among microorganisms lead to several types of multispecies biofilm formation. The spatial distribution of multispecies biofilms reflects microbial interactions and biofilm function. Then, we discuss the intrinsic factors and external manifestations of multispecies biofilm system succession. Several typical interspecies cooperation and competition modes and mechanisms of microbial communication were reviewed in this review. The main limitations of the studies included in this review are the relatively small number of studies of biofilms formed by functional microorganisms during fermentation and the lack of direct evidence for the formation process of multispecies biofilms and microbial interactions and communication within biofilms. This review aims to provide the food industry with a sufficient understanding of multispecies biofilms in food fermentation. Practical Application: Meanwhile, it offers a reference value for better controlling and utilizing biofilms during food fermentation process, and the improvement of the yield, quality, and safety of fermented products including Chinese Baijiu, cheeese,kefir, soy sauce, kombucha, and fermented olive.}, } @article {pmid35761698, year = {2022}, author = {Yi, Z and Yan, J and Ding, Z and Xie, J}, title = {The HD-GYP domain protein of Shewanella putrefaciens YZ08 regulates biofilm formation and spoilage activities.}, journal = {Food research international (Ottawa, Ont.)}, volume = {157}, number = {}, pages = {111466}, doi = {10.1016/j.foodres.2022.111466}, pmid = {35761698}, issn = {1873-7145}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Shewanella putrefaciens/genetics ; }, abstract = {Shewanella putrefaciens is an important spoilage bacteria in seafood and its ability to form biofilms in food processing environments increases the chances of food spoilage. Exploring the regulatory factors associated with biofilm formation and spoilage activity in S. putrefaciens is of great significance for extending the shelf life of seafood. In this work, the regulatory function of HD-GYP domain protein K2227_17660 in spoilage microorganism S. putrefaciens YZ08 was studied. The deletion mutant Δ17660 was developed to explore the effects of K2227_17660 in c-di-GMP content regulation, motility, biofilm formation, extracellular protease activity, and spoilage potential by phenotypic and transcriptional comparison with wild-type (WT) strain. Deletion of K2227_17660 significantly increased c-di-GMP content, biofilm biomass, the production of extracellular polysaccharide, trimethylamine (TMA), and putrescine compared with WT strains, and also affected membrane fatty acid composition. Furthermore, RT-qPCR results revealed the expression levels of genes associated with biofilm biomass, spoilage and unsaturated fatty acids (UFAs) synthesis changed in a manner consistent with the phenotypes. Our results indicated that K2227_17660 possesses phosphodiesterase (PDE) activity that controls the biofilm biomass and spoilage potential of S. putrefaciens. This study provided a basis for a correlation between c-di-GMP and food spoilage in S. putrefaciens, providing new insights into the control of food quality and safety.}, } @article {pmid35761654, year = {2022}, author = {Wu, Y and Ma, F and Pang, X and Chen, Y and Niu, A and Tan, S and Chen, X and Qiu, W and Wang, G}, title = {Involvement of AprD in regulating biofilm structure, matrix secretion, and cell metabolism of meat-borne Pseudomonas fragi during chilled storage.}, journal = {Food research international (Ottawa, Ont.)}, volume = {157}, number = {}, pages = {111400}, doi = {10.1016/j.foodres.2022.111400}, pmid = {35761654}, issn = {1873-7145}, mesh = {Biofilms ; Meat/analysis ; Metabolic Networks and Pathways ; Pseudomonas ; *Pseudomonas fragi/genetics/metabolism ; }, abstract = {Pseudomonas fragi is by far one of the most threatening species in the spoilage of chilled meat that is stored under aerobic conditions. The membrane protein AprD is a well-established regulator controlling protease secretion in Pseudomonas spp. However, its exact roles in modulating metabolic pathways and spoilage potential of P. fragi at the molecular level remain undefined. Here, an in-frame deletion mutation of aprD was used to explore the impacts on their biofilm structure, matrix secretion, and cell metabolism. The results showed that ΔaprD formed relatively disorganized loose aggregation in biofilm, resulting in a thinner structure and more dead cells. Meanwhile, marked changes in the content of extracellular carbohydrates and proteins were observed. Furthermore, intracellular metabolomic profiling revealed the involvement of aprD in several cellular metabolic pathways, mostly including the carbohydrate pathway, amino acid pathway, and nucleotide pathway, while the characterization of extracellular metabolism clarified the variations in the spoilage-related metabolites (e.g., creatine, IMP, spermine, fatty acids, amino acids, and oligopeptides) could be highly correlated with aprD deletion. In this finding, we indicated that aprD could be responsible for cell reproduction and in situ spoilage potential of P. fragi NMC25 during chilled storage by controlling related metabolism and nutrients utilization. Thus, our results will contribute to an improved understanding of the regulatory mechanism of aprD gene in meat spoilage contaminated with P. fragi, which can be valuable to ensure the quality and safety of meat.}, } @article {pmid35761627, year = {2022}, author = {Byun, KH and Han, SH and Choi, MW and Kim, BH and Park, SH and Ha, SD}, title = {Biofilm eradication ability of phage cocktail against Listeria monocytogenes biofilms formed on food contact materials and effect on virulence-related genes and biofilm structure.}, journal = {Food research international (Ottawa, Ont.)}, volume = {157}, number = {}, pages = {111367}, doi = {10.1016/j.foodres.2022.111367}, pmid = {35761627}, issn = {1873-7145}, mesh = {*Bacteriophages/genetics ; Biofilms ; Colony Count, Microbial ; *Listeria monocytogenes ; Virulence ; }, abstract = {Listeria monocytogenes is a foodborne pathogen that can form biofilms in food processing facilities even under unfavorable growth environment. This study aimed to evaluate the biofilm eradication ability of Listeria-specific bacteriophage (phage) cocktail (LMPC01+02+03) against L. monocytogenes young (1 day) and mature (3 days) biofilms formed on food contact materials (FCMs: polyethylene, polypropylene, and stainless steel) at 4, 15, and 30 °C. In addition, virulence-related genes and biofilm structure parameters of the phage-treated biofilms were investigated. The biofilm eradication ability of the phage cocktail was evaluated on 96 well and MBEC plate, and the results revealed that a multiplicity-of-infection (MOI) 100 of the phage cocktail exhibited the ability of eradicate biofilms. Using MOI 100, the phage cocktail treatment on the biofilms formed on FCMs for 8 h reduced over 2 log CFU/cm[2] of the young biofilms, and approximately 1 log CFU/cm[2] of the mature biofilms. In addition, the phage treatment against the biofilms resulted in a significant up-regulation of two genes (flaA and motB), and up/down-regulation or no changes in three genes (hlyA, prfA, and actA). Confocal and scanning electron microscopy images revealed the loss of the biofilm matrix after the phage treatment, and quantitative analysis revealed a reduction in the structural parameters of the biofilm, except the microcolonies at the substratum level, which increased. These results suggested that MOI 100 of the phage cocktail (LMPC01+02+03) was an effective tool for eradicating L. monocytogenes biofilms formed on FCMs, and it is essential to develop a countermeasure to eradicate the biofilm remaining after phage treatment.}, } @article {pmid35761055, year = {2022}, author = {Hofer, U}, title = {A new wrinkle in biofilm structure.}, journal = {Nature reviews. Microbiology}, volume = {20}, number = {9}, pages = {509}, pmid = {35761055}, issn = {1740-1534}, mesh = {Biofilms ; *Skin Aging ; }, } @article {pmid35760284, year = {2022}, author = {Liu, L and He, Y and Yang, H and Liu, W and Zheng, S and Qi, Y and Zhou, D and Zhang, Y and Yin, Z}, title = {Nlp enhances biofilm formation by Yersinia pestis biovar microtus.}, journal = {Microbial pathogenesis}, volume = {169}, number = {}, pages = {105659}, doi = {10.1016/j.micpath.2022.105659}, pmid = {35760284}, issn = {1096-1208}, mesh = {Animals ; Arvicolinae/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; *Plague ; *Yersinia pestis/metabolism ; }, abstract = {Biofilms formed by Yersinia pestis are able to attach to and block flea's proventriculus, which stimulates the transmission of this pathogen from fleas to mammals. In this study, we found that Nlp (YP1143) enhanced biofilm formation by Y. pestis and had regulatory effects on biofilm-associated genes at the transcriptional level. Phenotypic assays, including colony morphology assay, crystal violet staining, and Caenorhabditis elegans biofilm assay, disclosed that Nlp strongly promoted biofilm formation by Y. pestis. Further gene regulation assays showed that Nlp stimulated the expression of hmsHFRS, hmsCDE and hmsB, while had no regulatory effect on the expression of hmsT and hmsP at the transcriptional level. These findings promoted us to gain more understanding of the complex regulatory circuits controlling biofilm formation by Y. pestis.}, } @article {pmid35760234, year = {2022}, author = {Jin, Y and Zhao, B and Guo, W and Li, Y and Min, J and Miao, W}, title = {Penetration and photodynamic ablation of drug-resistant biofilm by cationic Iron oxide nanoparticles.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {348}, number = {}, pages = {911-923}, doi = {10.1016/j.jconrel.2022.06.038}, pmid = {35760234}, issn = {1873-4995}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cations/pharmacology ; *Chlorophyllides/pharmacology ; Magnetic Iron Oxide Nanoparticles ; Mammals ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; *Nanoparticles ; *Photochemotherapy ; Photosensitizing Agents/pharmacology/therapeutic use ; *Porphyrins/pharmacology/therapeutic use ; }, abstract = {As we step into the post-antibiotic era, the accelerated emergence of antibiotic-resistant pathogenic bacteria poses an increasingly serious threat to public health. The formation of antibiotic-resistant biofilms further challenges currently available drugs and treatment options, calling for novel strategies for effective ablation of such biofilm with minimal concern on safety and development of resistance. Herein, we report a novel type of photodynamic nanoagent, composed of chlorin e6 (Ce6)-loaded water-soluble chitosan-coated iron oxide nanoparticles (named Ce6@WCS-IONP), for drug-resistant bacteria killing and biofilm eradication. The fabricated Ce6@WCS-IONP has negligible toxicity to mammalian cells and exhibited equivalent singlet oxygen generation capacity to free Ce6; however, its association with methicillin-resistant Staphylococcus aureus (MRSA) was greatly enhanced, as evidenced by flow cytometry analysis and transmission electron microscope. In vitro studies verified that Ce6@WCS-IONP has superior photodynamic bactericidal effect against planktonic MRSA. Furthermore, with the aid of the cationic nature and small size, Ce6@WCS-IONP could effectively penetrate into MRSA biofilm, revealed by 3D fluorescence imaging. Both biomass analysis and viable bacteria counting demonstrated that Ce6@WCS-IONP showed potent biofilm ablation efficacy, averagely 7.1 log unit lower than that in free Ce6 group upon identical light irradiation. In addition, local treatment of MRSA-infected mice with Ce6@WCS-IONP plus light irradiation resulted in significant antibacterial and wound healing effect, accompanied by good biocompatibility in vivo. Collectively, photosensitizer-loaded cationic IONP with effective biofilm penetration and photodynamic eradication potential might be a promising nano platform in fighting against antibiotic-resistant microbial pathogen and biofilm.}, } @article {pmid35760177, year = {2022}, author = {Vendrell-Puigmitja, L and Proia, L and Espinosa, C and Barral-Fraga, L and Cañedo-Argüelles, M and Osorio, V and Casas, C and Llenas, L and Abril, M}, title = {Hypersaline mining effluents affect the structure and function of stream biofilm.}, journal = {The Science of the total environment}, volume = {843}, number = {}, pages = {156966}, doi = {10.1016/j.scitotenv.2022.156966}, pmid = {35760177}, issn = {1879-1026}, mesh = {Biofilms ; *Diatoms ; Ecosystem ; Humans ; Mining ; *Rivers/chemistry ; }, abstract = {The salinisation of freshwater ecosystems is a global environmental problem that threatens biodiversity, ecosystem functioning and human welfare. The aim of this study was to investigate the potential impact of a realistic salinity gradient on the structure and functioning of freshwater biofilms. The salinity gradient was based on the real ion concentration of a mining effluent from an abandoned mine in Germany. We exposed biofilm from a pristine stream to 5 increasing salinities (3 to 100 g L[-1]) under controlled conditions in artificial streams for 21 days. We evaluated its functional (photosynthetic efficiency, nutrient uptake, and microbial respiration) and structural responses (community composition, algal biomass and diatom, cyanobacteria and green algae metrics) over time. Then we compared their responses with an unexposed biofilm used as control. The functionality and structure of the biofilm exposed to the different salinities significantly decreased after short-term and long-term exposure, respectively. The community composition shifted to a new stable state where the most tolerant species increased their abundances. At the same time, we observed an increase in the community tolerance (measured as Pollution-Induced Community Tolerance) along the salinity gradient. This study provides relevant information on the salt threshold concentrations that can substantially damage algal cells (i.e., between 15 and 30 g L[-1]). The results provide new insights regarding the response and adaptation of stream biofilm to salinity and its potential implications at the ecosystem level.}, } @article {pmid35759644, year = {2022}, author = {Ben Hur, D and Kapach, G and Wani, NA and Kiper, E and Ashkenazi, M and Smollan, G and Keller, N and Efrati, O and Shai, Y}, title = {Antimicrobial Peptides against Multidrug-Resistant Pseudomonas aeruginosa Biofilm from Cystic Fibrosis Patients.}, journal = {Journal of medicinal chemistry}, volume = {65}, number = {13}, pages = {9050-9062}, pmid = {35759644}, issn = {1520-4804}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/therapeutic use ; Antimicrobial Peptides ; Biofilms ; *Cystic Fibrosis/drug therapy ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa ; }, abstract = {Lung infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and is mainly dominated by Pseudomonas aeruginosa. Treatment of CF-associated lung infections is problematic because the drugs are vulnerable to multidrug-resistant pathogens, many of which are major biofilm producers like P. aeruginosa. Antimicrobial peptides (AMPs) are essential components in all life forms and exhibit antimicrobial activity. Here we investigated a series of AMPs (d,l-K6L9), each composed of six lysines and nine leucines but differing in their sequence composed of l- and d-amino acids. The d,l-K6L9 peptides showed antimicrobial and antibiofilm activities against P. aeruginosa from CF patients. Furthermore, the data revealed that the d,l-K6L9 peptides are stable and resistant to degradation by CF sputum proteases and maintain their activity in a CF sputum environment. Additionally, the d,l-K6L9 peptides do not induce bacterial resistance. Overall, these findings should assist in the future development of alternative treatments against resistant bacterial biofilms.}, } @article {pmid35758758, year = {2022}, author = {Klementiev, AD and Whiteley, M}, title = {Development of a Versatile, Low-Cost Electrochemical System to Study Biofilm Redox Activity at the Micron Scale.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {14}, pages = {e0043422}, pmid = {35758758}, issn = {1098-5336}, support = {DE023193//HHS | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/ ; GM116547//HHS | NIH | National Institute of General Medical Sciences (NIGMS)/ ; DE029415//HHS | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/ ; }, mesh = {Aggregatibacter actinomycetemcomitans ; *Biofilms ; *Hydrogen Peroxide/metabolism ; Oxidation-Reduction ; Streptococcus gordonii/metabolism ; }, abstract = {Spatially resolving chemical landscapes surrounding microbial communities can provide insight into chemical interactions that dictate cellular physiology. Electrochemical techniques provide an attractive option for studying these interactions due to their robustness and high sensitivity. Unfortunately, commercial electrochemical platforms that are capable of measuring chemical activity on the micron scale are often expensive and do not easily perform multiple scanning techniques. Here, we report development of an inexpensive electrochemical system that features a combined micromanipulator and potentiostat component capable of scanning surfaces while measuring molecular concentrations or redox profiles. We validate this experimental platform for biological use with a two-species biofilm model composed of the oral bacterial pathogen Aggregatibacter actinomycetemcomitans and the oral commensal Streptococcus gordonii. We measure consumption of H2O2 by A. actinomycetemcomitans biofilms temporally and spatially, providing new insights into how A. actinomycetemcomitans responds to this S. gordonii-produced metabolite. We advance our platform to spatially measure redox activity above biofilms. Our analysis supports that redox activity surrounding biofilms is species specific, and the region immediately above an S. gordonii biofilm is highly oxidized compared to that above an A. actinomycetemcomitans biofilm. This work provides description and validation of a versatile, quantitative framework for studying bacterial redox-mediated physiology in an integrated and easily adaptable experimental platform. IMPORTANCE Scanning electrochemical probe microscopy methods can provide information of the chemical environment along a spatial surface with micron-scale resolution. These methods often require expensive instruments that perform optimized and highly sensitive niche techniques. Here, we describe a novel system that combines a micromanipulator that scans micron-sized electrodes across the surface of bacterial biofilms and a potentiostat, which performs various electrochemical techniques. This platform allows for spatial measurement of chemical gradients above live bacteria in real time, and as proof of concept, we utilize this setup to map H2O2 detoxification above an oral pathogen biofilm. We increased the versatility of this platform further by mapping redox potentials of biofilms in real time on the micron scale. Together, this system provides a technical framework for studying chemical interactions among microbes.}, } @article {pmid35758640, year = {2022}, author = {Wan, P and Guo, W and Wang, Y and Deng, M and Xiao, C and Chen, X}, title = {Photosensitizer-Polypeptide Conjugate for Effective Elimination of Candida albicans Biofilm.}, journal = {Advanced healthcare materials}, volume = {11}, number = {16}, pages = {e2200268}, doi = {10.1002/adhm.202200268}, pmid = {35758640}, issn = {2192-2659}, mesh = {Animals ; Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; *Fluconazole/pharmacology ; Humans ; Microbial Sensitivity Tests ; Peptides/pharmacology ; Photosensitizing Agents/pharmacology ; Rats ; }, abstract = {Persistent fungal infections caused by biofilms seriously endanger human health. In this study, a photosensitizer-polypeptide conjugate (PPa-cP) comprising a photosensitizer, pyropheophorbide a (PPa), and a cationic polypeptide (cP) is readily synthesized for effective antifungal and antibiofilm treatment. Compared with free PPa, the cationic PPa-cP shows enhanced binding ability to the negatively charged surface of Candida albicans (C. albicans) through electrostatic interactions. As a result, PPa-cP exhibits effective antifungal efficiency against both C. albicans and fluconazole-resistant C. albicans in vitro under light irradiation. The minimum inhibitory concentration (MIC) of PPa-cP for both C. albicans and fluconazole-resistant C. albicans is 1 µm. In addition, PPa-cP also shows improved penetration in a C. albicans biofilm, thus effectively eliminating the C. albicans biofilm by photodynamic effects. More importantly, PPa-cP demonstrats significantly enhanced therapeutic effects in a fluconazole-resistant C. albicans-infected rat model with minimal side effects. In conclusion, the current work presents an effective strategy to combat biofilm infections associated with biomedical equipment.}, } @article {pmid35756812, year = {2022}, author = {Filemban, H and Bhadila, G and Wang, X and Melo, MAS and Oates, TW and Weir, MD and Sun, J and Xu, HHK}, title = {Novel low-shrinkage-stress bioactive nanocomposite with anti-biofilm and remineralization capabilities to inhibit caries.}, journal = {Journal of dental sciences}, volume = {17}, number = {2}, pages = {811-821}, pmid = {35756812}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: A common reason for dental composite restoration failure is recurrent caries at the margins. Our objectives were to: (1) develop a novel low-shrinkage-stress, antibacterial and remineralizing resin composite; (2) evaluate the effects of dimethylaminohexadecyl methacrylate (DMAHDM) on mechanical properties, biofilm inhibition, calcium (Ca) and phosphate (P) ion release, degree of conversion, and shrinkage stress on the new low-shrinkage-stress resin composite for the first time.

MATERIAL AND METHODS: The resin consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE) with high resistance to salivary hydrolytic degradation. Composites were made with 0%-8% of DMAHDM for antibacterial activity, and 20% of nanoparticles of amorphous calcium phosphate (NACP) for remineralization. Mechanical properties and Streptococcus mutans biofilm growth on composites were assessed. Ca and P ion releases, degree of conversion and shrinkage stress were evaluated.

RESULTS: Adding 2-5% DMAHDM and 20% NACP into the low-shrinkage-stress composite did not compromise the mechanical properties (p > 0.05). The incorporation of DMAHDM greatly reduced S. mutans biofilm colony-forming units by 2-5 log and lactic acid production by 7 folds, compared to a commercial composite (p < 0.05). Adding 5% DMAHDM did not compromise the Ca and P ion release. The low-shrinkage-stress composite maintained a high degree of conversion of approximately 70%, while reducing the shrinkage stress by 37%, compared to a commercial control (p < 0.05).

CONCLUSION: The bioactive low-shrinkage-stress composite reduced the polymerization shrinkage stress, without compromising other properties. Increasing the DMAHDM content increased the antibacterial effect in a dose-dependent manner.}, } @article {pmid35756538, year = {2022}, author = {Cho, E and Hwang, JY and Park, JS and Oh, D and Oh, DC and Park, HG and Shin, J and Oh, KB}, title = {Inhibition of Streptococcus mutans adhesion and biofilm formation with small-molecule inhibitors of sortase A from Juniperus chinensis.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {2088937}, pmid = {35756538}, issn = {2000-2297}, abstract = {BACKGROUND: Streptococcus mutans, an important Gram-positive pathogen in dental caries, uses sortase A (SrtA) to anchor surface proteins to the bacterial cell wall, thereby promoting biofilm formation and attachment to the tooth surface.

DESIGN: Based on activity-guided separation, inhibitors of S. mutans SrtA were isolated from Juniperus chinensis and identified through combined spectroscopic analysis. Further effects of isolated SrtA inhibitor on S. mutans were evaluated on bacterial aggregation, adherence and biofilm formation.

RESULTS: Six compounds (1-6) were isolated from the dried heartwood of J. chinensis. A novel compound designated 3',3"-dihydroxy-(-)-matairesinol (1) was identified, which exhibited potent inhibitory activity toward S. mutans SrtA (IC50 = 16.1 μM) without affecting microbial viability (minimum inhibitory concentration > 300 μM). The results of subsequent bioassays using compound 1 indicated that this compound inhibits S. mutans aggregation, adhesion and biofilm formation on solid surfaces by inhibiting SrtA activity. The onset and magnitude of inhibition of adherence and biofilm formation in S. mutans treated with compound 1 at 4× the SrtA IC50 are comparable to the behaviors of the untreated srtA-deletion mutant.

CONCLUSION: Our findings suggest that small-molecule inhibitors of S. mutans SrtA may be useful for the prevention of dental plaque and treatment of dental microbial diseases.}, } @article {pmid35756067, year = {2022}, author = {Li, Y and Chen, N and Wu, Q and Liang, X and Yuan, X and Zhu, Z and Zheng, Y and Yu, S and Chen, M and Zhang, J and Wang, J and Ding, Y}, title = {A Flagella Hook Coding Gene flgE Positively Affects Biofilm Formation and Cereulide Production in Emetic Bacillus cereus.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {897836}, pmid = {35756067}, issn = {1664-302X}, abstract = {Bacillus cereus, an important foodborne pathogen, poses a risk to food safety and quality. Robust biofilm formation ability is one of the key properties that is responsible for the food contamination and food poisoning caused by B. cereus, especially the emetic strains. To investigate the mechanism of biofilm formation in emetic B. cereus strains, we screened for the mutants that fail to form biofilms by using random mutagenesis toward B. cereus 892-1, an emetic strain with strong biofilm formation ability. When knocking out flgE, a flagellar hook encoding gene, the mutant showed disappearance of flagellar structure and swimming ability. Further analysis revealed that both pellicle and ring presented defects in the null mutant compared with the wild-type and complementary strains. Compared with the flagellar paralytic strains Δ motA and Δ motB, the inhibition of biofilm formation by Δ flgE is not only caused by the inhibition of motility. Interestingly, Δ flgE also decreased the synthesis of cereulide. To our knowledge, this is the first report showing that a flagellar component can both affect the biofilm formation and cereulide production in emetic B. cereus, which can be used as the target to control the biohazard of emetic B. cereus.}, } @article {pmid35756031, year = {2022}, author = {Liu, J and Zhu, Y and Li, Y and Lu, Y and Xiong, K and Zhong, Q and Wang, J}, title = {Bacteriophage-Resistant Mutant of Enterococcus faecalis Is Impaired in Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {913023}, pmid = {35756031}, issn = {1664-302X}, abstract = {Enterococcus faecalis is a common gram-positive non-spore-forming bacterium in nature and is found in the upper respiratory tract, intestine, and mouth of healthy people. E. faecalis is also one of the common pathogens causing nosocomial infections and is resistant to several antibiotics commonly used in practice. Thus, treating drug-resistant E. faecalis with antibiotics is challenging, and new approaches are needed. In this study, we isolated a bacteriophage named EFap02 that targets E. faecalis strain EFa02 from sewage at Southwest Hospital. Phage EFap02 belongs to the Siphoviridae family with a long tail of approximately 210 nm, and EFap02 can tolerate a strong acid and alkali environment and high temperature. Its receptor was identified as the capsular polysaccharide. Phage-resistant mutants had loss-of-function mutations in glycosyltransferase (gtr2), which is responsible for capsular polysaccharide biosynthesis, and this caused the loss of capsular polysaccharide and interruption of phage adsorption. Although phage-resistant mutants against EFap02 can be selected, such mutants are impaired in biofilm formation due to the loss of capsular polysaccharide, which compromises its virulence. Therefore, this study provided a detailed description of the E. faecalis EFap02 phage with the potential for treating E. faecalis infection.}, } @article {pmid35754328, year = {2022}, author = {Ghafil, JA and İbrahim, BMS and Zgair, AK}, title = {Coating indwelling urinary catheters with moxifloxacin prevents biofilm formation by Burkholderia cepacia.}, journal = {Polimery w medycynie}, volume = {52}, number = {1}, pages = {7-11}, doi = {10.17219/pim/149986}, pmid = {35754328}, issn = {0370-0747}, mesh = {Biofilms ; *Burkholderia cepacia ; Catheters, Indwelling ; Moxifloxacin/pharmacology ; Urinary Catheterization ; Urinary Catheters ; }, abstract = {BACKGROUND: Burkholderia cepacia adhesion and biofilm formation onto abiotic surfaces is an important feature of clinically relevant isolates. The in vitro biofilm formation of B. cepacia onto coated indwelling urinary catheters (IDCs) with moxifloxacin has not been previously investigated.

OBJECTIVES: To examine the ability of B. cepacia to form biofilms on IDCs and the effect of coating IDCs with moxifloxacin on biofilm formation by B. cepacia in vitro.

MATERIAL AND METHODS: The adhesion of B. cepacia to coated and uncoated IDCs with moxifloxacin was evaluated. Pieces of IDCs were coated with moxifloxacin (adsorption method). The spectrophotometric method was used to check moxifloxacin leaching into tubes. Coated and uncoated tubes were incubated with 107 colony forming units (cfu)/mL of B. cepacia. The viable bacterial count was used to count the number of bacteria adhered to coated and uncoated IDC pieces.

RESULTS: A significant adhesion of B. cepacia to uncoated IDC pieces started 15 min after the incubation in a bacterial suspension (107 cfu/mL). A maximum adhesion was observed at 48 h. The pretreatment of IDCs with 100 μg/mL of moxifloxacin produced the best adsorption of antibiotic onto the IDCs. Coating IDC pieces with moxifloxacin significantly reduced the adhesion and biofilm formation of B. cepacia (p < 0.05) at various time intervals (1 h, 4 h and 24 h).

CONCLUSIONS: The present study has demonstrated for the first time that coated IDCs with moxifloxacin reduce B. cepacia adhesion and biofilm formation. This finding has opened the door to the production of the new generation IDCs that prevent bacteria from attaching and forming biofilms.}, } @article {pmid35753599, year = {2022}, author = {Mishra, P and Ch, S and Hong, SJ and Biswas, S and Roy, S}, title = {Antimicrobial peptide S100A12 (calgranulin C) inhibits growth, biofilm formation, pyoverdine secretion and suppresses type VI secretion system in Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {169}, number = {}, pages = {105654}, doi = {10.1016/j.micpath.2022.105654}, pmid = {35753599}, issn = {1096-1208}, mesh = {Animals ; Antimicrobial Peptides ; Biofilms ; *Keratitis/microbiology ; Leukocyte L1 Antigen Complex/metabolism ; Mice ; Oligopeptides ; Pseudomonas/metabolism ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/genetics ; S100A12 Protein/metabolism ; *Type VI Secretion Systems/genetics ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen and is the major cause of corneal infections in India and worldwide. The increase in antimicrobial resistance among Pseudomonas has prompted rise in significant research to develop alternative therapeutics. Antimicrobial peptides (AMPs) are considered as potent alternatives to combat bacterial infections. In this study, we investigated the role of S100A12, a host defense peptide, against PAO1 and an ocular clinical isolate. Increased expression of S100A12 was observed in corneal tissues obtained from Pseudomonas keratitis patients by immunohistochemistry. S100A12 significantly inhibited growth of Pseudomonas in vitro as determined from colony forming units. Furthermore, recombinant S100A12 reduced the corneal opacity and the bacterial load in a mouse model of Pseudomonas keratitis. Transcriptome changes in PAO1 in response to S100A12 was investigated using RNA sequencing. The pathway analysis of transcriptome data revealed that S100A12 inhibits expression of genes involved in pyoverdine synthesis and biofilm formation. It also impedes several important pathways like redox, pyocyanin synthesis and type 6 secretion system (T6SS). The transcriptome data was further validated by checking the expression of several affected genes by quantitative PCR. Our study sheds light on how S100A12 impacts Pseudomonas and that it might have the potential to be used as therapeutic intervention in addition to antibiotics to combat infection in future.}, } @article {pmid35752611, year = {2022}, author = {Revie, NM and Iyer, KR and Maxson, ME and Zhang, J and Yan, S and Fernandes, CM and Meyer, KJ and Chen, X and Skulska, I and Fogal, M and Sanchez, H and Hossain, S and Li, S and Yashiroda, Y and Hirano, H and Yoshida, M and Osada, H and Boone, C and Shapiro, RS and Andes, DR and Wright, GD and Nodwell, JR and Del Poeta, M and Burke, MD and Whitesell, L and Robbins, N and Cowen, LE}, title = {Targeting fungal membrane homeostasis with imidazopyrazoindoles impairs azole resistance and biofilm formation.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {3634}, pmid = {35752611}, issn = {2041-1723}, support = {I01 BX002624/BX/BLRD VA/United States ; FDN-143264//CIHR/Canada ; FDN-154288//CIHR/Canada ; R01 AI136934/AI/NIAID NIH HHS/United States ; MFE-176478//CIHR/Canada ; R01 AI116420/AI/NIAID NIH HHS/United States ; R01 AI125770/AI/NIAID NIH HHS/United States ; IK6 BX005386/BX/BLRD VA/United States ; R01 AI135812/AI/NIAID NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Antifungal Agents/pharmacology/therapeutic use ; *Azoles/pharmacology ; Biofilms ; Candida albicans ; Drug Resistance, Fungal ; *Fluconazole/pharmacology ; Homeostasis ; Microbial Sensitivity Tests ; Rats ; }, abstract = {Fungal infections cause more than 1.5 million deaths annually. With an increase in immune-deficient susceptible populations and the emergence of antifungal drug resistance, there is an urgent need for novel strategies to combat these life-threatening infections. Here, we use a combinatorial screening approach to identify an imidazopyrazoindole, NPD827, that synergizes with fluconazole against azole-sensitive and -resistant isolates of Candida albicans. NPD827 interacts with sterols, resulting in profound effects on fungal membrane homeostasis and induction of membrane-associated stress responses. The compound impairs virulence in a Caenorhabditis elegans model of candidiasis, blocks C. albicans filamentation in vitro, and prevents biofilm formation in a rat model of catheter infection by C. albicans. Collectively, this work identifies an imidazopyrazoindole scaffold with a non-protein-targeted mode of action that re-sensitizes the leading human fungal pathogen, C. albicans, to azole antifungals.}, } @article {pmid35750233, year = {2022}, author = {Cheng, Y and Wang, H and Deng, Z and Wang, J and Liu, Z and Chen, Y and Ma, Y and Li, B and Yang, L and Zhang, Z and Wu, L}, title = {Efficient removal of Imidacloprid and nutrients by algae-bacteria biofilm reactor (ABBR) in municipal wastewater: Performance, mechanisms and the importance of illumination.}, journal = {Chemosphere}, volume = {305}, number = {}, pages = {135418}, doi = {10.1016/j.chemosphere.2022.135418}, pmid = {35750233}, issn = {1879-1298}, mesh = {Bacteria ; Biofilms ; Bioreactors ; Lighting ; Neonicotinoids ; Nitro Compounds ; Nitrogen ; Nutrients ; Phosphorus ; *Waste Disposal, Fluid/methods ; *Wastewater/microbiology ; }, abstract = {Neonicotinoids, such as Imidacloprid (IMI), are frequently detected in water and wastewater, posing a threat on both the environment and the health of living things. In this work, a novel algae-bacteria biofilm reactor (ABBR) was constructed to remove IMI and conventional nutrients from municipal wastewater, aiming to explore the removal effect and advantage of ABBR. Results showed that ABBR achieved 74.9% removal of IMI under 80 μmol m[-2]·s[-1] light, higher than photobioreactor (PBR) without biofilm (61.2%) or ABBR under 40 μmol m[-2]·s[-1] light (48.4%) after 16 days of operation. Moreover, it also showed that ABBR allowed a marked improvement on the removal of total dissolved nitrogen (TDN), total dissolved phosphorus (TDP) and soluble chemical oxygen demand (sCOD). ABBR showed different IMI removal efficiencies and bacterial communities under different light conditions, indicating that light played an important role in driving ABBR. The merits of ABBR are including (i) ABBR showed rapid pollutant removal in a short time, (ii) in ABBR, stable consortiums were formed and chlorophyll content in effluent was very low, (iii) compared with PBR, degradation products in ABBR showed lower biological toxicity. Our study highlights the benefits of ABBR on IMI removing from municipal wastewater and provides an effective and environment-friendly engineering application potential of IMI removal.}, } @article {pmid35750120, year = {2022}, author = {Chen, X and Yuan, C and Zhu, Y and Liu, H and Chen, W and Zhang, Q}, title = {Bioaugmentation with Acinetobacter sp. TAC-1 to enhance nitrogen removal in swine wastewater by moving bed biofilm reactor inoculated with bacteria.}, journal = {Bioresource technology}, volume = {359}, number = {}, pages = {127506}, doi = {10.1016/j.biortech.2022.127506}, pmid = {35750120}, issn = {1873-2976}, mesh = {*Acinetobacter/genetics ; Animals ; Biofilms ; Bioreactors ; Denitrification ; Nitrification ; Nitrogen/analysis ; Swine ; *Wastewater ; }, abstract = {To enhance the performance of moving bed biofilm reactor (MBBR) inoculated with heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria, bioaugmentation with Acinetobacter sp. TAC-1 was firstly employed and then the treatment performance for real swine wastewater was presented in this study. Results indicated that NH4[+]-N and TN removal rates of bioaugmented reactor were significantly improved from 16.53 mg/L/h and 16.15 mg/L/h to 24.58 mg/L/h and 24.45 mg/L/h, respectively. The efficient removal performance (NH4[+]-N 95.01%, TN 86.40%) for real swine wastewater was achieved within 24 h. Microbial analysis indicated that the composition of functional bacteria varied with the introduction of Acinetobacter sp. TAC-1, especially the abundance of Acinetobacter, Paracoccus and Rhodococcus related to the nitrogen removal. Furthermore, bioaugmentation with Acinetobacter sp. TAC-1 increased abundance of enzymes and functional genes (nirS, nirK and norZ) corresponding to denitrification that may be responsible for the enhanced nitrogen removal performance.}, } @article {pmid35749910, year = {2022}, author = {Di Ciccio, P and Rubiola, S and Panebianco, F and Lomonaco, S and Allard, M and Bianchi, DM and Civera, T and Chiesa, F}, title = {Biofilm formation and genomic features of Listeria monocytogenes strains isolated from meat and dairy industries located in Piedmont (Italy).}, journal = {International journal of food microbiology}, volume = {378}, number = {}, pages = {109784}, doi = {10.1016/j.ijfoodmicro.2022.109784}, pmid = {35749910}, issn = {1879-3460}, mesh = {Biofilms ; Dairying ; Food Microbiology ; Genomics ; Humans ; *Listeria monocytogenes/genetics ; *Listeriosis ; Meat ; }, abstract = {Listeria monocytogenes is considered a major challenge for the food industry as it can persist for long periods in food processing plants by forming biofilms. The aims of this study were: i) to assess the biofilm producing ability of 57 Listeria monocytogenes isolates previously subjected to whole-genome sequencing (WGS); ii) to compare the levels of biofilm formation with the presence or absence of biofilm associated genes. To determine the presence or absence of a known set of biofilm associated genes, a comparative genomic analysis was performed on each strain. Among Listeria monocytogenes isolates, 58 %, 38.5 % and 3.5 % exhibited weak, moderate or strong biofilm production, respectively. No difference in biofilm production was observed between food and environmental isolates. The percentage of Listeria monocytogenes strains isolated from meat products (57 %) classified as moderate or strong biofilm producers was higher than the percentage obtained for strains isolated from dairy products (28 %). The presence of the Stress Survival Islet 1, the arsD stress gene and the truncated inlA protein was significantly associated with increased levels of biofilm. Combining biofilm phenotype with molecular and genotyping data may provide the opportunity to better understand the relationship between genes linked to biofilm formation in Listeria monocytogenes.}, } @article {pmid35749894, year = {2022}, author = {Balu, S and Bhunia, S and Gachhui, R and Mukherjee, J}, title = {Polycyclic aromatic hydrocarbon sequestration by intertidal phototrophic biofilms cultivated in hydrophobic and hydrophilic biofilm-promoting culture vessels.}, journal = {Journal of hazardous materials}, volume = {437}, number = {}, pages = {129318}, doi = {10.1016/j.jhazmat.2022.129318}, pmid = {35749894}, issn = {1873-3336}, mesh = {Biofilms ; Hydrophobic and Hydrophilic Interactions ; *Polycyclic Aromatic Hydrocarbons ; Polysaccharides/chemistry ; Uronic Acids ; }, abstract = {Phototrophic biofilms collected from intertidal sediments of the world's largest tidal mangrove forest were cultured in two sets of a biofilm-promoting culture vessel having hydrophilic glass surface and hydrophobic polymethyl methacrylate surface wherein 16 priority polycyclic aromatic hydrocarbons (PAHs) were spiked. Biofilms from three locations of the forest were most active in sequestering 98-100% of the spiked pollutants. PAH challenge did not alter the biofilm phototrophic community composition; rather biofilm biomass production and synthesis of photosynthetic pigments and extracellular polymeric substances (EPS) were enhanced. Photosynthetic pigment and EPS synthesis were sensitive to vessel-surface property. The lowest mean residual amounts of PAHs in the liquid medium as well as inside the biofilm were recorded in the very biofilm cultivated in the hydrophobic flask where highest values of biofilm biomass, total chlorophyll, released polysaccharidic (RPS) carbohydrates, RPS uronic acids, capsular polysaccharidic (CPS) carbohydrates, CPS proteins, CPS uronic acids and EPS hydrophobicity were obtained. Ratios of released RPS proteins: polysaccharides increased during PAH sequestration whereas the ratios of CPS proteins: polysaccharides remained constant. Efficacious PAH removal by the overlying phototrophic biofilm will reduce the entry of these contaminants in the sediments underneath and this strategy could be a model for "monitored natural recovery".}, } @article {pmid35749478, year = {2022}, author = {Nishimura, A and Nakagami, K and Kan, K and Morita, F and Takagi, H}, title = {Arginine inhibits Saccharomyces cerevisiae biofilm formation by inducing endocytosis of the arginine transporter Can1.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {86}, number = {9}, pages = {1300-1307}, doi = {10.1093/bbb/zbac094}, pmid = {35749478}, issn = {1347-6947}, support = {21K05504//Grant-in-Aid for Scientific Research/ ; }, mesh = {*Amino Acid Transport Systems, Basic/genetics/metabolism ; *Arginine/pharmacology ; Biofilms ; Endocytosis ; Membrane Glycoproteins/metabolism ; Membrane Transport Proteins/genetics ; *Saccharomyces cerevisiae/metabolism ; *Saccharomyces cerevisiae Proteins/genetics/metabolism ; }, abstract = {Biofilms are formed by the aggregation of microorganisms into multicellular structures that adhere to surfaces. Biofilm formation by yeast is a critical issue in clinical and industrial fields because of the strong adhesion of yeast biofilm to abiotic surfaces and tissues. Here, we clarified the arginine-mediated inhibition of biofilm formation by yeast. First, we showed that arginine inhibits biofilm formation in fungi such as Saccharomyces cerevisiae, Candida glabrata, and Cladosporium cladosporioides, but not in bacteria. In regard to the underlying mechanism, biochemical analysis indicated that arginine inhibits biofilm formation by suppressing Flo11-dependent flocculation. Intriguingly, a strain with deletion of the arginine transporter-encoding CAN1 was insensitive to arginine-mediated inhibition of biofilm formation. Finally, Can1 endocytosis appeared to be required for the inhibitory mechanism of biofilm formation by arginine. The present results could help to elucidate the molecular mechanism of yeast biofilm formation and its control.}, } @article {pmid35746441, year = {2022}, author = {Dollery, SJ and Harro, JM and Wiggins, TJ and Wille, BP and Kim, PC and Tobin, JK and Bushnell, RV and Tasker, NJPER and MacLeod, DA and Tobin, GJ}, title = {Select Whole-Cell Biofilm-Based Immunogens Protect against a Virulent Staphylococcus Isolate in a Stringent Implant Model of Infection.}, journal = {Vaccines}, volume = {10}, number = {6}, pages = {}, pmid = {35746441}, issn = {2076-393X}, support = {R43 AI145457/AI/NIAID NIH HHS/United States ; R43AI145457/NH/NIH HHS/United States ; }, abstract = {Many microbes of concern to human health remain without vaccines. We have developed a whole-microbe inactivation technology that enables us to rapidly inactivate large quantities of a pathogen while retaining epitopes that were destroyed by previous inactivation methods. The method that we call UVC-MDP inactivation can be used to make whole-cell vaccines with increased potency. We and others are exploring the possibility of using improved irradiation-inactivation technologies to develop whole-cell vaccines for numerous antibiotic-resistant microbes. Here, we apply UVC-MDP to produce candidate MRSA vaccines which we test in a stringent tibia implant model of infection challenged with a virulent MSRA strain. We report high levels of clearance in the model and observe a pattern of protection that correlates with the immunogen protein profile used for vaccination.}, } @article {pmid35745740, year = {2022}, author = {Falanga, A and Maione, A and La Pietra, A and de Alteriis, E and Vitale, S and Bellavita, R and Carotenuto, R and Turrà, D and Galdiero, S and Galdiero, E and Guida, M}, title = {Competitiveness during Dual-Species Biofilm Formation of Fusarium oxysporum and Candida albicans and a Novel Treatment Strategy.}, journal = {Pharmaceutics}, volume = {14}, number = {6}, pages = {}, pmid = {35745740}, issn = {1999-4923}, abstract = {During an infection, a single or multispecies biofilm can develop. Infections caused by non-dermatophyte molds, such as Fusarium spp. and yeasts, such as Candida spp., are particularly difficult to treat due to the formation of a mixed biofilm of the two species. Fusarium oxysporum is responsible for approximately 20% of human fusariosis, while Candida albicans is responsible for superficial mucosal and dermal infections and for disseminated bloodstream infections with a mortality rate above 40%. This study aims to investigate the interactions between C. albicans and F. oxysporum dual-species biofilm, considering variable formation conditions. Further, the ability of the WMR peptide, a modified version of myxinidin, to eradicate the mixed biofilm when used alone or in combination with fluconazole (FLC) was tested, and the efficacy of the combination of WMR and FLC at low doses was assessed, as well as its effect on the expression of some biofilm-related adhesin and hyphal regulatory genes. Finally, in order to confirm our findings in vivo and explore the synergistic effect of the two drugs, we utilized the Galleria mellonella infection model. We concluded that C. albicans negatively affects F. oxysporum growth in mixed biofilms. Combinatorial treatment by WMR and FLC significantly reduced the biomass and viability of both species in mature mixed biofilms, and these effects coincided with the reduced expression of biofilm-related genes in both fungi. Our results were confirmed in vivo since the synergistic antifungal activity of WMR and FLC increased the survival of infected larvae and reduced tissue invasion. These findings highlight the importance of drug combinations as an alternative treatment for C. albicans and F. oxysporum mixed biofilms.}, } @article {pmid35745739, year = {2022}, author = {Lattwein, KR and Beekers, I and Kouijzer, JJP and Leon-Grooters, M and Langeveld, SAG and van Rooij, T and van der Steen, AFW and de Jong, N and van Wamel, WJB and Kooiman, K}, title = {Dispersing and Sonoporating Biofilm-Associated Bacteria with Sonobactericide.}, journal = {Pharmaceutics}, volume = {14}, number = {6}, pages = {}, pmid = {35745739}, issn = {1999-4923}, support = {805308/ERC_/European Research Council/International ; }, abstract = {Bacteria encased in a biofilm poses significant challenges to successful treatment, since both the immune system and antibiotics are ineffective. Sonobactericide, which uses ultrasound and microbubbles, is a potential new strategy for increasing antimicrobial effectiveness or directly killing bacteria. Several studies suggest that sonobactericide can lead to bacterial dispersion or sonoporation (i.e., cell membrane permeabilization); however, real-time observations distinguishing individual bacteria during and directly after insonification are missing. Therefore, in this study, we investigated, in real-time and at high-resolution, the effects of ultrasound-induced microbubble oscillation on Staphylococcus aureus biofilms, without or with an antibiotic (oxacillin, 1 μg/mL). Biofilms were exposed to ultrasound (2 MHz, 100-400 kPa, 100-1000 cycles, every second for 30 s) during time-lapse confocal microscopy recordings of 10 min. Bacterial responses were quantified using post hoc image analysis with particle counting. Bacterial dispersion was observed as the dominant effect over sonoporation, resulting from oscillating microbubbles. Increasing pressure and cycles both led to significantly more dispersion, with the highest pressure leading to the most biofilm removal (up to 83.7%). Antibiotic presence led to more variable treatment responses, yet did not significantly impact the therapeutic efficacy of sonobactericide, suggesting synergism is not an immediate effect. These findings elucidate the direct effects induced by sonobactericide to best utilize its potential as a biofilm treatment strategy.}, } @article {pmid35745543, year = {2022}, author = {Silva, V and Correia, E and Pereira, JE and González-Machado, C and Capita, R and Alonso-Calleja, C and Igrejas, G and Poeta, P}, title = {Exploring the Biofilm Formation Capacity in S. pseudintermedius and Coagulase-Negative Staphylococci Species.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35745543}, issn = {2076-0817}, support = {SFRH/BD/137947/2018//Fundação para a Ciência e Tecnologia/ ; }, abstract = {The ability of biofilm formation seems to play an important role in the virulence of staphylococci. However, studies reporting biofilm formation of coagulase-negative staphylococci isolated from animals are still very scarce. Thus, we aimed to evaluate the biofilm-forming capacity of CoNS and S. pseudintermedius isolated from several animal species and to investigate the effect of conventional antimicrobials on biofilm reduction. A total of 35 S. pseudintermedius and 192 CoNS were included. Biofilm formation was accessed by the microtiter plate assay and the biofilms were stained by crystal violet. Association between biofilm formation and staphylococci species and antimicrobial resistance was also performed. Biofilm susceptibility testing was performed with tetracycline and amikacin at the minimum inhibitory concentration (MIC) and 10 × MIC. The metabolic activity of the biofilm cells after antimicrobial treatment was accessed by the XTT assay. All isolates formed biofilm, with S. urealyticus producing the most biofilm biomass and S. pseudintermedius producing the least biomass. There was a positive association between biofilm formation and multidrug resistance as well as resistance to individual antimicrobials. Neither tetracycline nor amikacin were able to eradicate the biofilm, not even at the highest concentration used. This study provides new insights into biofilm formation and the effects of antimicrobials on CoNS species.}, } @article {pmid35745014, year = {2022}, author = {Matchawong, A and Srisawat, C and Sangboonruang, S and Tharinjaroen, CS}, title = {The Ability of Nuclease-Resistant RNA Aptamer against Streptococcus suis Serotype 2, Strain P1/7 to Reduce Biofilm Formation In Vitro.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {12}, pages = {}, pmid = {35745014}, issn = {1420-3049}, support = {517803//National Research Council of Thailand/ ; //The Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University/ ; }, mesh = {Animals ; *Aptamers, Nucleotide/pharmacology ; Biofilms ; Serogroup ; *Streptococcal Infections/microbiology ; *Streptococcus suis ; Swine ; *Swine Diseases/microbiology ; }, abstract = {Streptococcus suis, a Gram-positive bacterium, is an important swine and human pathogen, with serotype 2 being the most prevalent strain found worldwide. Deafness, meningitis, and death (in severe cases) are observed in S. suis-infected cases. Development of the ligands that can bind to S. suis with high affinity and specificity could be beneficial for the diagnosis and treatment of S. suis infection. Herein, the nuclease-resistant RNA aptamers based on 2'-fluoropyrimidine modification against S. suis serotype 2, strain P1/7, were established using the cell- Systematic Evolution of Ligands by Exponential enrichment (SELEX) technique. One of the aptamers, R8-su12, could bind to the S. suis target strain as well as other S. suis serotypes, i.e., 1, 1/2, 9, and 14, but not to other bacteria tested, i.e., S. pneumoniae ATCC 49619, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853. Moreover, the R8-su12 RNA aptamer was also capable of inhibiting the biofilm formation of the S. suis target strain, making it potentially useful for the study of biofilm formation and the treatment of S. suis infection in humans and pigs in the future.}, } @article {pmid35744757, year = {2022}, author = {Sionov, RV and Steinberg, D}, title = {Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744757}, issn = {2076-2607}, abstract = {Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.}, } @article {pmid35744744, year = {2022}, author = {Tuck, B and Watkin, E and Somers, A and Forsyth, M and Machuca, LL}, title = {Enhancing Biocide Efficacy: Targeting Extracellular DNA for Marine Biofilm Disruption.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744744}, issn = {2076-2607}, support = {DP180101465//Australian Research Council/ ; }, abstract = {Biofilm formation is a global health, safety and economic concern. The extracellular composition of deleterious multispecies biofilms remains uncanvassed, leading to an absence of targeted biofilm mitigation strategies. Besides economic incentives, drive also exists from industry and research to develop and apply environmentally sustainable chemical treatments (biocides); especially in engineered systems associated with the marine environment. Recently, extracellular DNA (eDNA) was implicated as a critical structural polymer in marine biofilms. Additionally, an environmentally sustainable, multi-functional biocide was also introduced to manage corrosion and biofilm formation. To anticipate biofilm tolerance acquisition to chemical treatments and reduce biocide application quantities, the present research investigated eDNA as a target for biofilm dispersal and potential enhancement of biocide function. Results indicate that mature biofilm viability can be reduced by two-fold using reduced concentrations of the biocide alone (1 mM instead of the recommended 10 mM). Importantly, through the incorporation of an eDNA degradation stage, biocide function could be enhanced by a further ~90% (one further log reduction in viability). Biofilm architecture analysis post-treatment revealed that endonuclease targeting of the matrix allowed greater biocide penetration, leading to the observed viability reduction. Biofilm matrix eDNA is a promising target for biofilm dispersal and antimicrobial enhancement in clinical and engineered systems.}, } @article {pmid35744740, year = {2022}, author = {Kozień, Ł and Gallienne, E and Martin, O and Front, S and Strus, M and Heczko, P}, title = {PDIA, an Iminosugar Compound with a Wide Biofilm Inhibitory Spectrum Covering Both Gram-Positive and Gram-Negative Human Bacterial Pathogens.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744740}, issn = {2076-2607}, support = {2018/31/B/NZ6/02443//National Science Center/ ; N N401 547040//National Science Center/ ; }, abstract = {Many difficult-to-treat human infections related to catheters and other indwelling devices are caused by bacteria residing in biofilms. One of the key properties of microorganisms residing in a biofilm is decreased susceptibility towards antimicrobial agents. Therefore, many different approaches have been researched to destroy or inhibit biofilm production by bacteria. Different iminosugars (IS) were reported to inhibit biofilm formation in S. mutans, S. aureus, and P. aeruginosa. The aim of this study was to look for a spectrum of the activity in one of these IS. The iminosugar PDIA beta-1-C-propyl-1,4-dideoxy-1,4-imino-L-arabinitol was tested in vitro at the same concentration against 30 different strains of the most important Gram-negative and Gram-positive human pathogens looking for their biofilm production and viability at different time intervals. It appeared that PDIA inhibited biofilm production of Enterobacter spp., P. aeruginosa, Enterococcus spp. and S. aureus in 8 h, and Klebsiella spp., Acinetobacter spp. and S.epidermidis in 24 h. PDIA caused no growth inhibition of the tested bacteria at a concentration of 0.9 mM. Our results indicate a broad-spectrum biofilm inhibitory activity of PDIA. which may be the basis for future application studies that will help in control of the associated device and biofilm-related infections caused by a wide spectrum of the causative agents.}, } @article {pmid35744728, year = {2022}, author = {Drożdż, K and Ochońska, D and Ścibik, Ł and Gołda-Cępa, M and Biegun, K and Brzychczy-Włoch, M}, title = {The Frequency of Occurrence of Resistance and Genes Involved in the Process of Adhesion and Accumulation of Biofilm in Staphylococcus aureus Strains Isolated from Tracheostomy Tubes.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744728}, issn = {2076-2607}, support = {N41/DB5/000454//Jagiellonian University/ ; POWR.03.02.00-00- 468 I013/16//InterDokMed/ ; }, abstract = {Background: Bacterial biofilm on the surface of tracheostomy tubes (TTs) is a potential reservoir of potentially pathogenic bacteria, including S. aureus. For this reason, our study aimed to investigate biofilm production in vitro and the presence of icaAD and MSCRAMM genes in clinical S. aureus strains derived from TTs, with respect to antibiotic resistance and genetic variability. Methods: The clonality of the S. aureus strains was analyzed by the PFGE method. The assessment of drug resistance was based on the EUCAST recommendations. The isolates were evaluated for biofilm production by the microtiter plate method and the slime-forming ability was tested on Congo red agar (CRA). The presence of icaAD genes was investigated by PCR and MSCRAMM genes were detected by multiplex PCR. Results: A total of 60 patients were enrolled in the study. One TT was obtained from each patient (n = 60). Twenty-one TTs (35%) were colonized with S. aureus. A total of 24 strains were isolated as 3 patients showed colonization with 2 SA clones (as confirmed by PFGE). PFGE showed twenty-two unique molecular profiles. Two isolates (8%) turned out to be MRSA, but 50% were resistant to chloramphenicol, 25% to erythromycin and 8% to clindamycin (two cMLSB and four iMLSB phenotypes were detected). The microtiter plate method with crystal violet confirmed that 96% of the strains were biofilm formers. Representative strains were visualized by SEM. All isolates had clfAB, fnbA, ebpS and icaAD. Different MSCRAMM gene combinations were observed. Conclusions: the present study showed that the S. aureus isolated from the TTs has a high diversity of genotypes, a high level of antibiotic resistance and ability to produce biofilm.}, } @article {pmid35744727, year = {2022}, author = {Hou, J and Wang, L and Alm, M and Thomsen, P and Monsen, T and Ramstedt, M and Burmølle, M}, title = {Enhanced Antibiotic Tolerance of an In Vitro Multispecies Uropathogen Biofilm Model, Useful for Studies of Catheter-Associated Urinary Tract Infections.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744727}, issn = {2076-2607}, support = {R324-2019-1775//Lundbeck Foundation/ ; }, abstract = {Catheter-associated urinary tract infections (CAUTI) are a common clinical concern as they can lead to severe, persistent infections or bacteremia in long-term catheterized patients. This type of CAUTI is difficult to eradicate, as they are caused by multispecies biofilms that may have reduced susceptibility to antibiotics. Many new strategies to tackle CAUTI have been proposed in the past decade, including antibiotic combination treatments, surface modification and probiotic usage. However, those strategies were mainly assessed on mono- or dual-species biofilms that hardly represent the long-term CAUTI cases where, normally, 2-4 or even more species can be involved. We developed a four-species in vitro biofilm model on catheters involving clinical strains of Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca and Proteus mirabilis isolated from indwelling catheters. Interspecies interactions and responses to antibiotics were quantitatively assessed. Collaborative as well as competitive interactions were found among members in our model biofilm and those interactions affected the individual species' abundances upon exposure to antibiotics as mono-, dual- or multispecies biofilms. Our study shows complex interactions between species during the assessment of CAUTI control strategies for biofilms and highlights the necessity of evaluating treatment and control regimes in a multispecies setting.}, } @article {pmid35744683, year = {2022}, author = {Kolodkin-Gal, I and Cohen-Cymberknoh, M and Zamir, G and Tsesis, I and Rosen, E}, title = {Targeting Persistent Biofilm Infections: Reconsidering the Topography of the Infection Site during Model Selection.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744683}, issn = {2076-2607}, abstract = {The physiology of an organism in the environment reflects its interactions with the diverse physical, chemical, and biological properties of the surface. These principles come into consideration during model selection to study biofilm-host interactions. Biofilms are communities formed by beneficial and pathogenic bacteria, where cells are held together by a structured extracellular matrix. When biofilms are associated with a host, chemical gradients and their origins become highly relevant. Conventional biofilm laboratory models such as multiwall biofilm models and agar plate models poorly mimic these gradients. In contrast, ex vivo models possess the partial capacity to mimic the conditions of tissue-associated biofilm and a biofilm associated with a mineralized surface enriched in inorganic components, such as the human dentin. This review will highlight the progress achieved using these settings for two models of persistent infections: the infection of the lung tissue by Pseudomonas aeruginosa and the infection of the root canal by Enterococcus faecalis. For both models, we conclude that the limitations of the conventional in vitro systems necessitate a complimentary experimentation with clinically relevant ex vivo models during therapeutics development.}, } @article {pmid35744681, year = {2022}, author = {Carcione, D and Leccese, G and Conte, G and Rossi, E and Intra, J and Bonomi, A and Sabella, S and Moreo, M and Landini, P and Brilli, M and Paroni, M}, title = {Lack of Direct Correlation between Biofilm Formation and Antimicrobial Resistance in Clinical Staphylococcus epidermidis Isolates from an Italian Hospital.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744681}, issn = {2076-2607}, abstract = {Staphylococcus epidermidis is an opportunistic pathogen and a frequent cause of nosocomial infections. In this work, we show that, among 51 S. epidermidis isolates from an Italian hospital, only a minority displayed biofilm formation, regardless of their isolation source (peripheral blood, catheter, or skin wounds); however, among the biofilm-producing isolates, those from catheters were the most efficient in biofilm formation. Interestingly, most isolates including strong biofilm producers displayed production levels of PIA (polysaccharide intercellular adhesin), the main S. epidermidis extracellular polysaccharide, similar to reference S. epidermidis strains classified as non-biofilm formers, and much lower than those classified as intermediate or high biofilm formers, possibly suggesting that high levels of PIA production do not confer a particular advantage for clinical isolates. Finally, while for the reference S. epidermidis strains the biofilm production clearly correlated with the decreased sensitivity to antibiotics, in particular, protein synthesis inhibitors, in our clinical isolates, such positive correlation was limited to tetracycline. In contrast, we observed an inverse correlation between biofilm formation and the minimal inhibitory concentrations for levofloxacin and teicoplanin. In addition, in growth conditions favoring PIA production, the biofilm-forming isolates showed increased sensitivity to daptomycin, clindamycin, and erythromycin, with increased tolerance to the trimethoprim/sulfamethoxazole association. The lack of direct correlation between the biofilm production and increased tolerance to antibiotics in S. epidermidis isolates from a clinical setting would suggest, at least for some antimicrobials, the possible existence of a trade-off between the production of biofilm determinants and antibiotic resistance.}, } @article {pmid35744637, year = {2022}, author = {Ma, PY and Chong, CW and Than, LTL and Sulong, AB and Ho, KL and Neela, VK and Sekawi, Z and Liew, YK}, title = {Impact of IsaA Gene Disruption: Decreasing Staphylococcal Biofilm and Alteration of Transcriptomic and Proteomic Profiles.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744637}, issn = {2076-2607}, support = {FRGS/1/2018/SKK11/IMU/03/1//Fundamental Research Grant Scheme (FRGS)/ ; }, abstract = {Staphylococcus aureus expresses diverse proteins at different stages of growth. The immunodominant staphylococcal antigen A (IsaA) is one of the proteins that is constitutively produced by S. aureus during colonisation and infection. SACOL2584 (or isaA) is the gene that encodes this protein. It has been suggested that IsaA can hydrolyse cell walls, and there is still need to study isaA gene disruption to analyse its impact on staphylococcal phenotypes and on alteration to its transcription and protein profiles. In the present study, the growth curve in RPMI medium (which mimics human plasma), autolytic activity, cell wall morphology, fibronectin and fibrinogen adhesion and biofilm formation of S. aureus SH1000 (wildtype) was compared to that of S. aureus MS001 (isaA mutant). RNA sequencing and liquid chromatography-tandem mass spectrometry were carried out on samples of both S. aureus strains taken during the exponential growth phase, followed by bioinformatics analysis. Disruption of isaA had no obvious effect on the growth curve and autolysis ability or thickness of cell walls, but this study revealed significant strength of fibronectin adherence in S. aureus MS001. In particular, the isaA mutant formed less biofilm than S. aureus SH1000. In addition, proteomics and transcriptomics showed that the adhesin/biofilm-related genes and hemolysin genes, such as sasF, sarX and hlgC, were consistently downregulated with isaA gene disruption. The majority of the upregulated genes or proteins in S. aureus MS001 were pur genes. Taken together, this study provides insight into how isaA disruption changes the expression of other genes and has implications regarding biofilm formation and biological processes.}, } @article {pmid35744626, year = {2022}, author = {Qin, Y and Angelini, LL and Chai, Y}, title = {Bacillus subtilis Cell Differentiation, Biofilm Formation and Environmental Prevalence.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744626}, issn = {2076-2607}, support = {1651732//National Science Foundation/ ; CAAS-ZDRW202009//Agricultural Science and Technology Innovation Program of CAAS, China/ ; }, abstract = {Bacillus subtilis is a soil-dwelling, spore-forming Gram-positive bacterium capable of cell differentiation. For decades, B. subtilis has been used as a model organism to study development of specialized cell types. In this minireview, we discuss cell differentiation in B. subtilis, covering both past research and recent progresses, and the role of cell differentiation in biofilm formation and prevalence of this bacterium in the environment. We review B. subtilis as a classic model for studies of endospore formation, and highlight more recent investigations on cell fate determination and generation of multiple cell types during biofilm formation. We present mechanistic details of how cell fate determination and mutually exclusive cell differentiation are regulated during biofilm formation.}, } @article {pmid35744621, year = {2022}, author = {Ballén, V and Cepas, V and Ratia, C and Gabasa, Y and Soto, SM}, title = {Clinical Escherichia coli: From Biofilm Formation to New Antibiofilm Strategies.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744621}, issn = {2076-2607}, support = {PI19/00478//Instituto de Salud Carlos III/ ; REIPI RD12/0015/0013//Spanish Network for Research in Infectious Diseases from the Instituto de Salud Carlos III together with the European Development Regional Funds/ ; REIPI RD16/0016/0010//Spanish Network for Research in Infectious Diseases from the Instituto de Salud Carlos III together with the European Development Regional Funds/ ; 2014-2020//European Development Regional Fund "A way to achieve Europe" and operative program Intel-ligent Growth/ ; COLCIENCIAS Scholarship program N. 756//Ministerio de Ciencia, Tecnología e Innovación (Colombia)/ ; }, abstract = {Escherichia coli is one of the species most frequently involved in biofilm-related diseases, being especially important in urinary tract infections, causing relapses or chronic infections. Compared to their planktonic analogues, biofilms confer to the bacteria the capacity to be up to 1000-fold more resistant to antibiotics and to evade the action of the host's immune system. For this reason, biofilm-related infections are very difficult to treat. To develop new strategies against biofilms, it is important to know the mechanisms involved in their formation. In this review, the different steps of biofilm formation in E. coli, the mechanisms of tolerance to antimicrobials and new compounds and strategies to combat biofilms are discussed.}, } @article {pmid35744599, year = {2022}, author = {Lacotte, PA and Simons, A and Bouttier, S and Malet-Villemagne, J and Nicolas, V and Janoir, C}, title = {Inhibition of In Vitro Clostridioides difficile Biofilm Formation by the Probiotic Yeast Saccharomyces boulardii CNCM I-745 through Modification of the Extracellular Matrix Composition.}, journal = {Microorganisms}, volume = {10}, number = {6}, pages = {}, pmid = {35744599}, issn = {2076-2607}, support = {No number//Biocodex, Gentilly, France/ ; }, abstract = {Clostridioides difficile is responsible for post-antibiotic diarrhea and most of the pseudomembranous colitis cases. Multiple recurrences, one of the major challenges faced in C. difficile infection (CDI) management, can be considered as chronic infections, and the role of biofilm formation in CDI recurrences is now widely considered. Therefore, we explored if the probiotic yeast Saccharomyces boulardii CNCM I-745 could impact the in vitro formation of C. difficile biofilm. Biomass staining and viable bacterial cell quantification showed that live S. boulardii exerts an antagonistic effect on the biofilm formation for the three C. difficile strains tested. Confocal laser scanning microscopy observation revealed a weakening and an average thickness reduction of the biofilm structure when C. difficile is co-incubated with S. boulardii, compared to the single-species bacterial biofilm structure. These effects, that were not detected with another genetically close yeast, S. cerevisiae, seemed to require direct contact between the probiotic yeast and the bacterium. Quantification of the extrapolymeric matrix components, as well as results obtained after DNase treatment, revealed a significant decrease of eDNA, an essential structural component of the C. difficile biofilm matrix, in the dual-species biofilm. This modification could explain the reduced cohesion and robustness of C. difficile biofilms formed in the presence of S. boulardii CNCM I-745 and be involved in S. boulardii clinical preventive effect against CDI recurrences.}, } @article {pmid35744098, year = {2022}, author = {De Francesco, F and Riccio, M and Jimi, S}, title = {Contribution of Topical Agents such as Hyaluronic Acid and Silver Sulfadiazine to Wound Healing and Management of Bacterial Biofilm.}, journal = {Medicina (Kaunas, Lithuania)}, volume = {58}, number = {6}, pages = {}, pmid = {35744098}, issn = {1648-9144}, mesh = {Animals ; Biofilms ; Humans ; *Hyaluronic Acid/pharmacology/therapeutic use ; Retrospective Studies ; *Silver Sulfadiazine/pharmacology/therapeutic use ; Wound Healing ; }, abstract = {Background and Objectives: Wound healing is commonly associated with critical bacterial colonization or bacterial infection, which induces prolonged inflammation, resulting in delayed re-epithelialization. An appropriate wound dressing requires a humid environment, which also functions as a barrier against bacterial contamination and will accelerate a regenerative response of the wound. Silver sulfadiazine (SSD) is used to prevent wound infection. Hyaluronic acid (HA) is an extracellular matrix component involved in tissue regeneration. This retrospective study was conducted to evaluate the effectiveness of cream and gauze pads based on hyaluronic acid at low molecular weight (200 kDa) and silver sulfadiazine 1% in the wound healing process. In addition, we examined SSD action on biofilms in vitro and on animal wounds, obtaining positive outcomes therefrom. Materials and Methods: We selected 80 patients with complicated chronic wounds of different etiologies, including diabetes mellitus (10), post-traumatic ulcers (45), burns (15), and superficial abrasion (10). Results: After 8 weeks, ulcer size was decreased in 95 ± 2% of the treated patients; a significant reduction in the inflammatory process was observed from day 14 onwards (p < 0.01 vs. baseline), considering improvement of the surrounding skin and reduction of the bacterial load. The SSD treatment decreased bacterial colony proliferation, both in planktonic state and in biofilm, in a dose-dependent manner on the wound but inhibited the development of tissue granulation at the highest dose (800 μg/wound). Conclusions: In conclusion, the combined action of SSD and HA is clinically effective in improving wound healing.}, } @article {pmid35743833, year = {2022}, author = {Gaglione, R and Pane, K and De Luca, M and Franzese, M and Arciello, A and Trama, F and Brancorsini, S and Salvatore, M and Illiano, E and Costantini, E}, title = {Novel Antimicrobial Strategies to Prevent Biofilm Infections in Catheters after Radical Cystectomy: A Pilot Study.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {6}, pages = {}, pmid = {35743833}, issn = {2075-1729}, abstract = {Catheter-associated infections in bladder cancer patients, following radical cystectomy or ureterocutaneostomy, are very frequent, and the development of antibiotic resistance poses great challenges for treating biofilm-based infections. Here, we characterized bacterial communities from catheters of patients who had undergone radical cystectomy for muscle-invasive bladder cancer. We evaluated the efficacy of conventional antibiotics, alone or combined with the human ApoB-derived antimicrobial peptide r(P)ApoBL[Ala], to treat ureteral catheter-colonizing bacterial communities on clinically isolated bacteria. Microbial communities adhering to indwelling catheters were collected during the patients' regular catheter change schedules (28 days) and extracted within 48 h. Living bacteria were characterized using selective media and biochemical assays. Biofilm growth and novel antimicrobial strategies were analyzed using confocal laser scanning microscopy. Statistical analyses confirmed the relevance of the biofilm reduction induced by conventional antibiotics (fosfomycin, ceftriaxone, ciprofloxacin, gentamicin, and tetracycline) and a well-characterized human antimicrobial peptide r(P)ApoBL[Ala] (1:20 ratio, respectively). Catheters showed polymicrobial communities, with Enterobactericiae and Proteus isolates predominating. In all samples, we recorded a meaningful reduction in biofilms, in both biomass and thickness, upon treatment with the antimicrobial peptide r(P)ApoBL[Ala] in combination with low concentrations of conventional antibiotics. The results suggest that combinations of conventional antibiotics and human antimicrobial peptides might synergistically counteract biofilm growth on ureteral catheters, suggesting novel avenues for preventing catheter-associated infections in patients who have undergone radical cystectomy and ureterocutaneostomy.}, } @article {pmid35742906, year = {2022}, author = {Jahan, F and Chinni, SV and Samuggam, S and Reddy, LV and Solayappan, M and Su Yin, L}, title = {The Complex Mechanism of the Salmonella typhi Biofilm Formation That Facilitates Pathogenicity: A Review.}, journal = {International journal of molecular sciences}, volume = {23}, number = {12}, pages = {}, pmid = {35742906}, issn = {1422-0067}, support = {FRGS/1/2018/STG03/AIMST/02/2//Ministry of Higher Education/ ; }, mesh = {Biofilms ; Gallbladder ; Humans ; *Salmonella typhi ; *Typhoid Fever ; Virulence ; }, abstract = {Salmonella enterica serovar Typhi (S. typhi) is an intracellular pathogen belonging to the Enterobacteriaceae family, where biofilm (aggregation and colonization of cells) formation is one of their advantageous traits. Salmonella typhi is the causative agent of typhoid fever in the human body and is exceptionally host specific. It is transmitted through the fecal-oral route by consuming contaminated food or water. This subspecies is quite intelligent to evade the innate detection and immune response of the host body, leading to systemic dissemination. Consequently, during the period of illness, the gallbladder becomes a harbor and may develop antibiotic resistance. Afterwards, they start contributing to the continuous damage of epithelium cells and make the host asymptomatic and potential carriers of this pathogen for an extended period. Statistically, almost 5% of infected people with Salmonella typhi become chronic carriers and are ready to contribute to future transmission by biofilm formation. Biofilm development is already recognized to link with pathogenicity and plays a crucial role in persistency within the human body. This review seeks to discuss some of the crucial factors related to biofilm development and its mechanism of interaction causing pathogenicity. Understanding the connections between these things will open up a new avenue for finding therapeutic approaches to combat pathogenicity.}, } @article {pmid35742863, year = {2022}, author = {Rahman, MA and Amirkhani, A and Chowdhury, D and Mempin, M and Molloy, MP and Deva, AK and Vickery, K and Hu, H}, title = {Proteome of Staphylococcus aureus Biofilm Changes Significantly with Aging.}, journal = {International journal of molecular sciences}, volume = {23}, number = {12}, pages = {}, pmid = {35742863}, issn = {1422-0067}, mesh = {Biofilms ; Humans ; Proteome/metabolism ; *Staphylococcal Infections/drug therapy ; *Staphylococcus aureus/metabolism ; Sugars/metabolism ; }, abstract = {Staphylococcus aureus is a notorious biofilm-producing pathogen that is frequently isolated from implantable medical device infections. As biofilm ages, it becomes more tolerant to antimicrobial treatment leading to treatment failure and necessitating the costly removal of infected devices. In this study, we performed in-solution digestion followed by TMT-based high-throughput mass spectrometry and investigated what changes occur in the proteome of S. aureus biofilm grown for 3-days and 12-days in comparison with 24 h planktonic. It showed that proteins associated with biosynthetic processes, ABC transporter pathway, virulence proteins, and shikimate kinase pathway were significantly upregulated in a 3-day biofilm, while proteins associated with sugar transporter, degradation, and stress response were downregulated. Interestingly, in a 3-day biofilm, we observed numerous proteins involved in the central metabolism pathways which could lead to biofilm growth under diverse environments by providing an alternative metabolic route to utilize energy. In 12-day biofilms, proteins associated with peptidoglycan biosynthesis, sugar transporters, and stress responses were upregulated, whereas proteins associated with ABC transporters, DNA replication, and adhesion proteins were downregulated. Gene Ontology analysis revealed that more proteins are involved in metabolic processes in 3dwb compared with 12dwb. Furthermore, we observed significant variations in the formation of biofilms resulting from changes in the level of metabolic activity in the different growth modes of biofilms that could be a significant factor in S. aureus biofilm maturation and persistence. Collectively, potential marker proteins were identified and further characterized to understand their exact role in S. aureus biofilm development, which may shed light on possible new therapeutic regimes in the treatment of biofilm-related implant-associated infections.}, } @article {pmid35740385, year = {2022}, author = {Shaghayegh, G and Cooksley, C and Ramezanpour, M and Wormald, PJ and Psaltis, AJ and Vreugde, S}, title = {Chronic Rhinosinusitis, S. aureus Biofilm and Secreted Products, Inflammatory Responses, and Disease Severity.}, journal = {Biomedicines}, volume = {10}, number = {6}, pages = {}, pmid = {35740385}, issn = {2227-9059}, abstract = {Chronic rhinosinusitis (CRS) is a persistent inflammation of the nasal cavity and paranasal sinuses associated with tissue remodelling, dysfunction of the sinuses' natural defence mechanisms, and induction of different inflammatory clusters. The etiopathogenesis of CRS remains elusive, and both environmental factors, such as bacterial biofilms and the host's general condition, are thought to play a role. Bacterial biofilms have significant clinical relevance due to their potential to cause resistance to antimicrobial therapy and host defenses. Despite substantial medical advances, some CRS patients suffer from recalcitrant disease that is unresponsive to medical and surgical treatments. Those patients often have nasal polyps with tissue eosinophilia, S. aureus-dominant mucosal biofilm, comorbid asthma, and a severely compromised quality of life. This review aims to summarise the contemporary knowledge of inflammatory cells/pathways in CRS, the role of bacterial biofilm, and their impact on the severity of the disease. Here, an emphasis is placed on S. aureus biofilm and its secreted products. A better understanding of these factors might offer important diagnostic and therapeutic perceptions for recalcitrant disease.}, } @article {pmid35740208, year = {2022}, author = {Radunovic, M and Barac, M and Kuzmanovic Pficer, J and Pavlica, D and Jovanovic, A and Pucar, A and Petrovic, S}, title = {Antifungal Susceptibility of Candida albicans Isolated from Tongue and Subgingival Biofilm of Periodontitis Patients.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35740208}, issn = {2079-6382}, support = {451-03-68/2022-14/200129//the Ministry of Education, Science and Technological De-velopment, Republic of Serbia/ ; }, abstract = {The subgingival biofilm, as the most complex microbial community, has been proven to be reservoir of Candida spp. The main concept of this study was to investigate if there is a difference between the sensitivity of Candida albicans (C. albicans) isolated from tongue and subgingival areas of periodontitis patients to antifungal agents. The aim of the study was to determine: (1) the distribution of different Candida species in the tongue and subgingival samples of periodontitis patients; (2) the susceptibility of Candida albicans strains from tongue and subgingival biofilm to the effects of commonly used antifungal agents: fluconazole, amphotericin B and itraconazole; (3) the correlation between the susceptibility of Candida albicans and clinical periodontal parameters. Tongue and subgingival biofilm samples of periodontitis subjects (N = 163) were examined. Susceptibility was tested when the same Candida species was isolated from both sites (17 subjects). Candida spp. were isolated in 23.3% of tongue and 21.5% of the subgingival samples. All isolates were susceptible to amphotericin B, while 64.71% of tongue and 52.94% of subgingival isolates were susceptible to fluconazole. A low frequency of itraconazole susceptibility was observed for tongue (17.64%) and subgingival isolates (11.76%). The correlations between full-mouth plaque score and Minimal Inhibitory Concentration (MIC) for tongue isolates were strongly positive for all antimycotics. Positive correlation was also observed between moderate periodontal destruction and MICs for tongue and subgingival isolates. The susceptibility of C. albicans to antifungals correlate with oral hygiene and moderate periodontal destruction. There is no difference in antifungal susceptibility between tongue and subgingival isolates.}, } @article {pmid35740178, year = {2022}, author = {Silva, V and Correia, E and Pereira, JE and González-Machado, C and Capita, R and Alonso-Calleja, C and Igrejas, G and Poeta, P}, title = {Biofilm Formation of Staphylococcus aureus from Pets, Livestock, and Wild Animals: Relationship with Clonal Lineages and Antimicrobial Resistance.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35740178}, issn = {2079-6382}, support = {SFRH/BD/137947/2018//Fundação para a Ciência e Tecnologia/ ; }, abstract = {This study aimed to compare the biofilm formation ability of Staphylococcus aureus isolated from a wide range of animals and study the association between biofilm formation and antimicrobial resistance and genetic lineages. A total of 214 S. aureus strains isolated from pets, livestock, and wild animals were evaluated regarding their ability to form biofilms by the microtiter biofilm assay and their structure via confocal scanning laser microscopy. Statistical analysis was used to find an association between biofilm formation and antimicrobial resistance, multidrug resistance, sequence types (STs), spa and agr-types of the isolates. The antimicrobial susceptibility of 24 h-old biofilms was assessed against minimum inhibitory concentrations (MIC) and 10× MIC of amikacin and tetracycline, and the biomass reduction was measured. The metabolic activity of biofilms after antimicrobial treatment was evaluated by the XTT assay. All isolates were had the ability to form biofilms. Yet, significant differences in biofilm biomass production were detected among animal species. Multidrug resistance had a positive association with biofilm formation as well as methicillin-resistance. Significant differences were also detected among the clonal lineages of the isolates. Both tetracycline and amikacin were able to significantly reduce the biofilm mass. However, none of the antimicrobials were able to eradicate the biofilm at the maximum concentration used. Our results provide important information on the biofilm-forming capacity of animal-adapted S. aureus isolates, which may have potential implications for the development of new biofilm-targeted therapeutics.}, } @article {pmid35740134, year = {2022}, author = {Takenaka, S and Sotozono, M and Ohkura, N and Noiri, Y}, title = {Evidence on the Use of Mouthwash for the Control of Supragingival Biofilm and Its Potential Adverse Effects.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35740134}, issn = {2079-6382}, support = {19H03958H//Japan Society for the Promotion of Science/ ; }, abstract = {Antimicrobial mouthwash improves supragingival biofilm control when used in conjunction with mechanical removal as part of an oral hygiene routine. Mouthwash is intended to suppress bacterial adhesion during biofilm formation processes and is not aimed at mature biofilms. The most common evidence-based effects of mouthwash on the subgingival biofilm include the inhibition of biofilm accumulation and its anti-gingivitis property, followed by its cariostatic activities. There has been no significant change in the strength of the evidence over the last decade. A strategy for biofilm control that relies on the elimination of bacteria may cause a variety of side effects. The exposure of mature oral biofilms to mouthwash is associated with several possible adverse reactions, such as the emergence of resistant strains, the effects of the residual structure, enhanced pathogenicity following retarded penetration, and ecological changes to the microbiota. These concerns require further elucidation. This review aims to reconfirm the intended effects of mouthwash on oral biofilm control by summarizing systematic reviews from the last decade and to discuss the limitations of mouthwash and potential adverse reactions to its use. In the future, the strategy for oral biofilm control may shift to reducing the biofilm by detaching it or modulating its quality, rather than eliminating it, to preserve the benefits of the normal resident oral microflora.}, } @article {pmid35740122, year = {2022}, author = {Babosan, A and Gaschet, M and Muggeo, A and Jové, T and Skurnik, D and Ploy, MC and de Champs, C and Reffuveille, F and Guillard, T}, title = {A qnrD-Plasmid Promotes Biofilm Formation and Class 1 Integron Gene Cassette Rearrangements in Escherichia coli.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35740122}, issn = {2079-6382}, abstract = {Bacteria within biofilms may be exposed to sub-minimum inhibitory concentrations (sub-MICs) of antibiotics. Cell-to-cell contact within biofilms facilitates horizontal gene transfers and favors induction of the SOS response. Altogether, it participates in the emergence of antibiotic resistance. Aminoglycosides at sub-MICs can induce the SOS response through NO accumulation in E. coli carrying the small plasmid with the quinolone resistance qnrD gene (pDIJ09-518a). In this study, we show that in E. coli pDIJ09-518a, the SOS response triggered by sub-MICs of aminoglycosides has important consequences, promoting genetic rearrangement in class 1 integrons and biofilm formation. We found that the integrase expression was increased in E. coli carrying pDIJ09-518a in the presence of tobramycin, which was not observed for the WT isogenic strain that did not carry the qnrD-plasmid. Moreover, we showed that biofilm production was significantly increased in E. coli WT/pDIJ09-518a compared to the WT strain. However, such a higher production was decreased when the Hmp-NO detoxification pathway was fully functional by overexpressing Hmp. Our results showing that a qnrD-plasmid can promote biofilm formation in E. coli and potentiate the acquisition and spread of resistance determinants for other antibiotics complicate the attempts to counteract antibiotic resistance and prevention of biofilm development even further. We anticipate that our findings emphasize the complex challenges that will impact the decisions about antibiotic stewardship, and other decisions related to retaining antibiotics as effective drugs and the development of new drugs.}, } @article {pmid35740119, year = {2022}, author = {Necel, A and Bloch, S and Topka-Bielecka, G and Janiszewska, A and Łukasiak, A and Nejman-Faleńczyk, B and Węgrzyn, G}, title = {Synergistic Effects of Bacteriophage vB_Eco4-M7 and Selected Antibiotics on the Biofilm Formed by Shiga Toxin-Producing Escherichia coli.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {35740119}, issn = {2079-6382}, support = {D000.MN.05.20//University of Gdańsk/ ; 531-D020-D242-21//University of Gdańsk/ ; }, abstract = {Apart from antibiotic resistance of pathogenic bacteria, the formation of biofilms is a feature that makes bacterial infections especially difficulty to treat. Shiga toxin-producing Escherichia coli (STEC) strains are dangerous pathogens, causing severe infections in humans, and capable of biofilm production. We have reported previously the identification and characterization of the vB_Eco4-M7 bacteriophage, infecting various STEC strains. It was suggested that this phage might be potentially used in phage therapy against these bacteria. Here, we tested the effects of vB_Eco4-M7 alone or in a phage cocktail with another STEC-infecting phage, and/or in a combination with different antibiotics (ciprofloxacin and rifampicin) on biofilm formed by a model STEC strain, named E. coli O157:H7 (ST2-8624). The vB_Eco4-M7 phage appeared effective in anti-biofilm action in all these experimental conditions (2-3-fold reduction of the biofilm density, and 2-3 orders of magnitude reduction of the number of bacterial cells). However, the highest efficiency in reducing a biofilm's density and number of bacterial cells was observed when phage infection preceded antibiotic treatment (6-fold reduction of the biofilm density, and 5-6 orders of magnitude reduction of the number of bacterial cells). Previous reports indicated that the use of antibiotics to treat STEC-caused infections might be dangerous due to the induction of Shiga toxin-converting prophages from bacterial genomes under stress conditions caused by antibacterial agents. We found that ciprofloxacin was almost as efficient in inducing prophages from the E. coli O15:H7 (ST2-8624) genome as a classical inducer, mitomycin C, while no detectable prophage induction could be observed in rifampicin-treated STEC cells. Therefore, we conclude the latter antibiotic or similarly acting compounds might be candidate(s) as effective and safe drug(s) when used in combination with phage therapy to combat STEC-mediated infections.}, } @article {pmid35739732, year = {2022}, author = {Ji, H and Hu, H and Tang, Q and Kang, X and Liu, X and Zhao, L and Jing, R and Wu, M and Li, G and Zhou, X and Liu, J and Wang, Q and Cong, H and Wu, L and Qin, Y}, title = {Precisely controlled and deeply penetrated micro-nano hybrid multifunctional motors with enhanced antibacterial activity against refractory biofilm infections.}, journal = {Journal of hazardous materials}, volume = {436}, number = {}, pages = {129210}, doi = {10.1016/j.jhazmat.2022.129210}, pmid = {35739732}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Humans ; *Hydrogen Peroxide/pharmacology ; *Manganese Compounds/pharmacology ; Oxides ; }, abstract = {The biofilm resistance of microorganisms has severe economic and environmental implications, especially the contamination of facilities associated with human life, including medical implants, air-conditioning systems, water supply systems, and food-processing equipment, resulting in the prevalence of infectious diseases. Once bacteria form biofilms, their antibiotic resistance can increase by 10-1,000-fold, posing a great challenge to the treatment of related diseases. In order to overcome the contamination of bacterial biofilm, destroying the biofilm's matrix so as to solve the penetration depth dilemma of antibacterial agents is the most effective way. Here, a magnetically controlled multifunctional micromotor was developed by using H2O2 as the fuel and MnO2 as the catalyst to treat bacterial biofilm infection. In the presence of H2O2, the as-prepared motors could be self-propelled by the generated oxygen microbubbles. Thereby, the remotely controlled motors could drill into the EPS of biofilm and disrupt them completely with the help of bubbles. Finally, the generated highly toxic •OH could efficiently kill the unprotected bacteria. This strategy combined the mechanical damage, highly toxic •OH, and precise magnetic guidance in one system, which could effectively eliminate biologically infectious fouling in microchannels within 10 min, possessing a wide range of practical application prospects especially in large scale and complex infection sites.}, } @article {pmid35739657, year = {2022}, author = {Geng, N and Xia, Y and Lu, D and Bai, Y and Zhao, Y and Wang, H and Ren, L and Xu, C and Hua, E and Sun, G and Chen, X}, title = {The bacterial community structure in epiphytic biofilm on submerged macrophyte Potamogetom crispus L. and its contribution to heavy metal accumulation in an urban industrial area in Hangzhou.}, journal = {Journal of hazardous materials}, volume = {430}, number = {}, pages = {128455}, doi = {10.1016/j.jhazmat.2022.128455}, pmid = {35739657}, issn = {1873-3336}, mesh = {Bioaccumulation ; Biofilms ; *Metals, Heavy ; *Potamogetonaceae ; *Water Pollutants, Chemical/analysis ; }, abstract = {Submerged macrophytes and their epiphytic biofilms are important media for metal transport/transformation in aquatic environment. However, the bacterial community structure and the contribution of the epiphytic biofilm to the heavy metal accumulation remain unclear. Therefore, in this study, water, sediment, submerged macrophyte (Potamogeton crispus L.) and its epiphytic biofilm samples in three sites of the moat in the industrial area of Hangzhou were collected for analyzing. The bacterial community structure was significantly impacted by the TN concentrations, and Genus Aeromonas (24.5-41.8%), Acinetobacter (16.2-29.8%) and Pseudomonas (12.6-23.6%) dominated in all epiphytic biofilm samples, which had the heavy metal pollutant resistibility. The contents of Cr in biofilms (7.4-8.3 mg/kg, DW) were significantly higher than those in leaves (1.0-2.4 mg/kg, DW), while the contents of Cu (11.0-13.9 mg/kg, DW) in leaves were significantly higher than those in biofilms (0.7-3.9 mg/kg, DW) in all the three sites. The BCF values of metals in the biofilm were followed the order of YF < IC < ETS. The results indicated that the epiphytic biofilm had positive effects on the metal bioaccumulation, and the metal accumulation ability increased with the hydrodynamic forces. Bioaccumulation by the epiphytic biofilm may be an effective way for metal (especially Cr) remediation.}, } @article {pmid35739327, year = {2022}, author = {Soliemani, O and Salimi, F and Rezaei, A}, title = {Characterization of exopolysaccharide produced by probiotic Enterococcus durans DU1 and evaluation of its anti-biofilm activity.}, journal = {Archives of microbiology}, volume = {204}, number = {7}, pages = {419}, pmid = {35739327}, issn = {1432-072X}, mesh = {Biofilms ; Enterococcus ; *Polysaccharides, Bacterial ; *Probiotics ; RNA, Ribosomal, 16S/genetics ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus ; }, abstract = {Exopolysaccharides (EPS) produced by lactic acid bacteria are complicated polymers with industrial applications. LAB were isolated, screened for EPS production, and their probiotic properties determined. The anti-biofilm activity of EPS was investigated. Safety of EPS-producing isolate was investigated and it was molecularly identified through 16S rRNA sequencing. Finally, anti-biofilm and emulsification activity of EPS was studied and it was characterized using FT-IR, TGA, [1]H-NMR, DLS and HPLC. Thirteen LAB were isolated from dairy products. They showed probiotic characteristics like acid resistance (0-6.51 CFU ml[-1]) hydrophobicity (8-54.04%), autoaggregation (0% [t = 2 h]-99.8% [t = 24 h]) and coaggregation with food borne pathogens. Among them, Enterococcus durans DU1 had ability to produce EPS. EPS of Enterococcus durans DU1 showed antibiofilm activity against Y. enterocolitica (24.06-51.36%), S. aureus (12.33-49.6%), and B. cereus (11.66-27.16%). FT-IR showed this EPS had characteristic absorption peaks due to the presence of the pyran ring of sugars. [1]H NMR showed that EPS has N-acetyl, methyl, and alkyl groups in its structure. The HPLC analysis showed that EPS is a heteropolysaccharide and consists of sucrose, glucose, and fructose. EPS showed significant thermal stability (20% weight loss) under 300 °C and zeta potential of - 18.1 mV. This EPS can be used in the food industry with no adverse effect on consumers.}, } @article {pmid35738989, year = {2022}, author = {Hernandez-Cuellar, E and Guerrero-Barrera, AL and Avelar-Gonzalez, FJ and Díaz, JM and Santiago, AS and Chávez-Reyes, J and Poblano-Sánchez, E}, title = {Characterization of Candida albicans and Staphylococcus aureus polymicrobial biofilm on different surfaces.}, journal = {Revista iberoamericana de micologia}, volume = {39}, number = {2}, pages = {36-43}, doi = {10.1016/j.riam.2022.04.001}, pmid = {35738989}, issn = {2173-9188}, mesh = {*Anti-Infective Agents ; Biofilms ; *Candida albicans ; Glucose/metabolism/pharmacology ; Staphylococcus aureus ; }, abstract = {BACKGROUND: Staphylococcus aureus and Candida albicans have been co-isolated from biofilm-associated diseases such as denture stomatitis, periodontitis, and burn wound infections, as well as from medical devices. However, the polymicrobial biofilm of both microorganisms has not been fully characterized.

AIMS: To characterize the polymicrobial biofilm of C. albicans and S. aureus in terms of microbial density, synergy, composition, structure, and stability against antimicrobials and chemical agents.

METHODS: Crystal violet assay was used to measure the biofilm formation. Scanning electron microscopy and confocal microscopy were used to analyze the structure and chemical composition of the biofilms, respectively.

RESULTS: Supplemented media with fetal bovine serum (FBS) decreased the biofilm formation of S. aureus and the polymicrobial biofilm. For C. albicans, depending on the culture media, the addition of glucose or FBS had a positive effect in biofilm formation. FBS decreased the adhesion to polystyrene wells for both microorganisms. Supplementing the media with glucose and FBS enhanced the growth of C. albicans and S. aureus, respectively. It seems that C. albicans contributes the most to the adhesion process and to the general structure of the biofilms on all the surfaces tested, including a catheter model. Interestingly, S. aureus showed a great adhesion capacity to the surface of C. albicans in the biofilms. Proteins and β-1,6-linked polysaccharides seem to be the most important molecules in the polymicrobial biofilm.

CONCLUSIONS: The polymicrobial biofilm had a complex structure, with C. albicans serving as a scaffold where S. aureus adheres, preferentially to the hyphal form of the fungus. Detection of polymicrobial infections and characterization of biofilms will be necessary in the future to provide a better treatment.}, } @article {pmid35736669, year = {2022}, author = {Sharma, A and Vashistt, J and Shrivastava, R}, title = {Mycobacterium fortuitum fabG4 knockdown studies: Implication as pellicle and biofilm specific drug target.}, journal = {Journal of basic microbiology}, volume = {62}, number = {12}, pages = {1504-1513}, doi = {10.1002/jobm.202200230}, pmid = {35736669}, issn = {1521-4028}, mesh = {*Mycobacterium fortuitum/genetics ; Biofilms ; Virulence ; Fatty Acids ; }, abstract = {The fatty acid biosynthesis pathway is crucial for the formation of the mycobacterial cell envelope. The fatty acid synthase type-II (FAS-II) components are attractive targets for designing anti-biofilm inhibitors. Literature review, bioinformatics analysis, cloning, and sequencing led to the identification of a novel Mycobacterium fortuitum FAS-II gene MFfabG4 which interacts with mycobacterial proteins involved in biofilm formation. A manually curated M. fortuitum fatty acid biosynthesis pathway has been proposed exploiting functional studies from the Kyoto Encyclopedia of Genes and Genomes and Mycobrowser databases for MFFabG4. M. fortuitum MFfabG4 knockdown strain (FA) was constructed and validated by quantitative polymerase chain reaction. The FA strain displayed unstructured smooth colony architecture, correlating with decreased pathogenicity and virulence. MFfabG4 knockdown resulted in diminished pellicle and attenuated biofilm formation, along with impaired sliding motility, and reduced cell sedimentation. The FA strain showed lowered cell surface hydrophobicity, indicating attenuation in M. fortuitum intracellular infection-causing ability. Stress survival studies showed the requirement of MFfabG4 for survival in a nutrient-starved environment. The results indicate that MFfabG4 maintains the physiology of the cell envelope and is required for the formation of M. fortuitum pellicle and biofilm. The study corroborates the role of MFfabG4 as a pellicle- and biofilm-specific drug target and a potential diagnostic marker for M. fortuitum and related pathogenic mycobacteria.}, } @article {pmid35736039, year = {2022}, author = {Souza, SO and Raposo, BL and Sarmento-Neto, JF and Rebouças, JS and Macêdo, DPC and Figueiredo, RCBQ and Santos, BS and Freitas, AZ and Cabral Filho, PE and Ribeiro, MS and Fontes, A}, title = {Photoinactivation of Yeast and Biofilm Communities of Candida albicans Mediated by ZnTnHex-2-PyP[4+] Porphyrin.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {6}, pages = {}, pmid = {35736039}, issn = {2309-608X}, support = {219677_Z_19_Z/WT_/Wellcome Trust/United Kingdom ; 406450/2021-8//National Council for Scientific and Technological Development/ ; APQ-0573-2.09/18//Fundação de Amparo à Ciência e Tecnologia de Pernambuco/ ; 2018/20226-7//São Paulo Research Foundation/ ; 465763/2014-6//Instituto Nacional de Ciência e Tecnologia de Fotônica (INCT-INFo)/ ; }, abstract = {Candida albicans is the main cause of superficial candidiasis. While the antifungals available are defied by biofilm formation and resistance emergence, antimicrobial photodynamic inactivation (aPDI) arises as an alternative antifungal therapy. The tetracationic metalloporphyrin Zn(II) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (ZnTnHex-2-PyP[4+]) has high photoefficiency and improved cellular interactions. We investigated the ZnTnHex-2-PyP[4+] as a photosensitizer (PS) to photoinactivate yeasts and biofilms of C. albicans strains (ATCC 10231 and ATCC 90028) using a blue light-emitting diode. The photoinactivation of yeasts was evaluated by quantifying the colony forming units. The aPDI of ATCC 90028 biofilms was assessed by the MTT assay, propidium iodide (PI) labeling, and scanning electron microscopy. Mammalian cytotoxicity was investigated in Vero cells using MTT assay. The aPDI (4.3 J/cm[2]) promoted eradication of yeasts at 0.8 and 1.5 µM of PS for ATCC 10231 and ATCC 90028, respectively. At 0.8 µM and same light dose, aPDI-treated biofilms showed intense PI labeling, about 89% decrease in the cell viability, and structural alterations with reduced hyphae. No considerable toxicity was observed in mammalian cells. Our results introduce the ZnTnHex-2-PyP[4+] as a promising PS to photoinactivate both yeasts and biofilms of C. albicans, stimulating studies with other Candida species and resistant isolates.}, } @article {pmid35735992, year = {2022}, author = {Bulock, LL and Ahn, J and Shinde, D and Pandey, S and Sarmiento, C and Thomas, VC and Guda, C and Bayles, KW and Sadykov, MR}, title = {Interplay of CodY and CcpA in Regulating Central Metabolism and Biofilm Formation in Staphylococcus aureus.}, journal = {Journal of bacteriology}, volume = {204}, number = {7}, pages = {e0061721}, pmid = {35735992}, issn = {1098-5530}, support = {P30 CA036727/CA/NCI NIH HHS/United States ; R01 AI125588/AI/NIAID NIH HHS/United States ; P20 GM103427/GM/NIGMS NIH HHS/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; R01 AI125589/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Humans ; *Staphylococcal Infections ; *Staphylococcus aureus/metabolism ; }, abstract = {Staphylococcus aureus is a medically important pathogen with high metabolic versatility allowing it to infect various niches within a host. S. aureus utilizes two major transcriptional regulators, namely, CodY and CcpA, to remodel metabolic and virulence gene expression in response to changing environmental conditions. Previous studies revealed that inactivation of either codY or ccpA has a pronounced impact on different aspects of staphylococcal physiology and pathogenesis. To determine the contribution and interplay of these two regulators in modulating central metabolism, virulence, and biofilm development, we constructed and characterized the codY ccpA double mutant in S. aureus UAMS-1. In line with previous studies, we found that CcpA and CodY control the cellular metabolic status by altering carbon flux through the central and overflow metabolic pathways. Our results demonstrate that ccpA inactivation impairs biofilm formation and decreases incorporation of extracellular DNA (eDNA) into the biofilm matrix, whereas disrupting codY resulted in a robust structured biofilm tethered together with eDNA and polysaccharide intercellular adhesin (PIA). Interestingly, inactivation of both codY and ccpA decreases biofilm biomass and reduces eDNA release in the double mutant. Compared with the inactivation of codY, the codY ccpA mutant did not overexpress toxins but maintained overexpression of amino acid metabolism pathways. Furthermore, the codY ccpA mutant produced large amounts of PIA, in contrast to the wild-type strain and ccpA mutant. Combined, the results of this study suggest that the coordinated action of CodY and CcpA modulate central metabolism, virulence gene expression, and biofilm-associated genes to optimize growth on preferred carbon sources until starvation sets in. IMPORTANCE Staphylococcus aureus is a leading cause of biofilm-associated infections, including infective endocarditis, worldwide. A greater understanding of metabolic forces driving biofilm formation in S. aureus is essential for the identification of novel therapeutic targets and for the development of new strategies to combat this medically important pathogen. This study characterizes the interplay and regulation of central metabolism and biofilm development by two global transcriptional regulators, CodY and CcpA. We found that the lack of CcpA and/or CodY have different impacts on intracellular metabolic status leading to a formation of morphologically altered biofilms. Overall, the results of this study provide new insights into our understanding of metabolism-mediated regulation of biofilm development in S. aureus.}, } @article {pmid35735075, year = {2022}, author = {Pamukçu, A and Erdoğan, N and Şen Karaman, D}, title = {Polyethylenimine-grafted mesoporous silica nanocarriers markedly enhance the bactericidal effect of curcumin against Staphylococcus aureus biofilm.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {110}, number = {11}, pages = {2506-2520}, pmid = {35735075}, issn = {1552-4981}, support = {//Council of Higher Education 100/2000 doctoral scholarship/ ; //The Turkish Scientific and Technological Research Council 2211-A BIDEB doctoral scholarship/ ; 319S024//The Turkish Scientific and Technological Research Council/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Curcumin/chemistry/pharmacology ; Drug Carriers/chemistry ; Mice ; Microbial Sensitivity Tests ; Polyethyleneimine/pharmacology ; Silicon Dioxide/chemistry/pharmacology ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; }, abstract = {The recalcitrant nature of biofilms makes biofilm-associated infections difficult to treat in modern medicine. Biofilms have a high vulnerability to antibiotics and a limited repertoire of antibiotics could act on matured biofilms. This issue has resulted in a gradual paradigm shift in drug discovery and therapy, with anti-biofilm compounds being sought alongside new drug carriers. A potential solution to biofilm-associated infections is to employ antibiofilm treatments, which can attack biofilms from many fronts. Nanocarriers are promising in this regard because they can be entrapped within biofilm matrix, target biofilm matrix, and provide local drug delivery to inhibit biofilm formation. In this study, curcumin as an herbal extract was loaded onto hyperbranched polyethylenimine-grafted mesoporous silica nanoparticles (F-MSN-PEI/Cur) and antibiofilm investigations were performed. The F-MSN-PEI/Cur design has the potential to repurpose curcumin as an antibiofilm agent by increasing its solubility and lowering the required doses for the destruction of matured biofilms as well as suppressing biofilm development. Using imaging and spectroscopic techniques, we assessed the interaction of F-MSN-PEI/Cur with Staphylococcus aureus bacterial cells and determined the impact of F-MSN-PEI/Cur on eradicating matured biofilms and suppressing biofilm development. The F-MSN-PEI/Cur design is highly cytocompatible, as observed by the cytotoxicity screening investigations on L929 mouse fibroblast cell line. Our findings show that F-MSN-PEI/Cur design reduces the bacterial cell viability, inhibits biofilm formation, and induces biofilm eradication, which is attributed to F-MSN-PEI/Cur design having the potential to repurpose the antibiofilm activity of curcumin-herbal extract.}, } @article {pmid35733961, year = {2022}, author = {Guo, M and Tan, S and Zhu, J and Sun, A and Du, P and Liu, X}, title = {Genes Involved in Biofilm Matrix Formation of the Food Spoiler Pseudomonas fluorescens PF07.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {881043}, pmid = {35733961}, issn = {1664-302X}, abstract = {The extracellular matrix is essential for the biofilm formation of food spoilers. Pseudomonas fluorescens PF07 is a previous isolate from spoiled marine fish; however, the genes involved in the extracellular matrix formation of PF07 biofilms remain poorly defined. In this study, PF07 formed a wrinkled macrocolony biofilm through the high production of extracellular matrix. The genes involved in biofilm matrix formation and regulation were screened and identified by RNA-seq-dependent transcriptomic analysis and gene knock-out analysis. The macrocolony biofilms of PF07 grown for 5 days (PF07_5d) were compared with those grown for 1 day (PF07_1d). A total of 1,403 genes were significantly differentially expressed during biofilm formation. These mainly include the genes related to biofilm matrix proteins, polysaccharides, rhamnolipids, secretion system, biofilm regulation, and metabolism. Among them, functional amyloid genes fapABCDE were highly upregulated in the mature biofilm, and the operon fapA-E had a -24/-12 promoter dependent on the sigma factor RpoN. Moreover, the RNA-seq analyses of the rpoN mutant, compared with PF07, revealed 159 genes were differentially expressed in the macrocolony biofilms, and fapA-E genes were positively regulated by RpoN. In addition, the deletion mutants of fapC, rpoN, and brfA (a novel gene coding for an RpoN-dependent transcriptional regulator) were defective in forming mature macrocolony biofilms, solid surface-associated (SSA) biofilms, and pellicles, and they showed significantly reduced biofilm matrices. The fap genes were significantly downregulated in ΔbrfA, as in ΔrpoN. These findings suggest that the functional amyloid Fap is the main component of PF07 biofilm matrices, and RpoN may directly regulate the transcription of fap genes, in conjunction with BrfA. These genes may serve as potential molecular targets for screening new anti-biofilm agents or for biofilm detection in food environments.}, } @article {pmid35731072, year = {2022}, author = {Bai, P and Li, Y and Bai, J and Xu, H}, title = {Markedly decreased growth rate and biofilm formation ability of Acinetobacter schindleri after a long-duration (64 days) spaceflight.}, journal = {European review for medical and pharmacological sciences}, volume = {26}, number = {11}, pages = {4001-4015}, doi = {10.26355/eurrev_202206_28971}, pmid = {35731072}, issn = {2284-0729}, mesh = {*Acinetobacter/genetics ; Biofilms ; *Space Flight ; Transcriptome ; }, abstract = {OBJECTIVE: The objective of this study was to investigate the effects of long-duration space flight on the biological characteristics of Acinetobacter schindleri (A. schindleri).

MATERIALS AND METHODS: In this study, an A. schindleri strain was collected from condensate water of the Shenzhou-10 spacecraft and then was sent into space again to the Tiangong-2 space lab for a long-duration spaceflight (64 days). Later, the impacts of the long-duration spaceflight on phenotype, genome and transcriptome of A. schindleri were analyzed.

RESULTS: It was found that the long-duration spaceflight markedly decreased the growth rate and biofilm formation ability of A. schindleri. Furthermore, comparative genomic and transcriptomic analyses revealed that the decreased growth rate might be associated with differentially expressed genes (DEGs) involved in transmembrane transport, energy production and conversion, and biofilm was reduced due to downregulation of the pil and algR genes.

CONCLUSIONS: The findings are of major importance for predicting bacterial pathogenesis mechanisms and possible spacecraft contamination during long-duration spaceflights in the future.}, } @article {pmid35730273, year = {2022}, author = {Hughes, JM and Eberl, HJ and Sonner, S}, title = {A mathematical model of discrete attachment to a cellulolytic biofilm using random DEs.}, journal = {Mathematical biosciences and engineering : MBE}, volume = {19}, number = {7}, pages = {6582-6619}, doi = {10.3934/mbe.2022310}, pmid = {35730273}, issn = {1551-0018}, mesh = {*Biofilms ; Biomass ; Computer Simulation ; Models, Biological ; *Models, Theoretical ; }, abstract = {We propose a new mathematical framework for the addition of stochastic attachment to biofilm models, via the use of random ordinary differential equations. We focus our approach on a spatially explicit model of cellulolytic biofilm growth and formation that comprises a PDE-ODE coupled system to describe the biomass and carbon respectively. The model equations are discretized in space using a standard finite volume method. We introduce discrete attachment events into the discretized model via an impulse function with a standard stochastic process as input. We solve our model with an implicit ODE solver. We provide basic simulations to investigate the qualitative features of our model. We then perform a grid refinement study to investigate the spatial convergence of our model. We investigate model behaviour while varying key attachment parameters. Lastly, we use our attachment model to provide evidence for a stable travelling wave solution to the original PDE-ODE coupled system.}, } @article {pmid35729017, year = {2022}, author = {Haji Hossein Tabrizi, A and Habibi, M and Foroohi, F and Mohammadian, T and Asadi Karam, MR}, title = {Investigation of the effects of antimicrobial and anti-biofilm peptide IDR1018 and chitosan nanoparticles on ciprofloxacin-resistant Escherichia coli.}, journal = {Journal of basic microbiology}, volume = {62}, number = {10}, pages = {1229-1240}, doi = {10.1002/jobm.202200156}, pmid = {35729017}, issn = {1521-4028}, mesh = {Anti-Bacterial Agents/chemistry ; Antimicrobial Cationic Peptides ; Biofilms ; *Chitosan/chemistry/pharmacology ; Ciprofloxacin/pharmacology/therapeutic use ; *Escherichia coli Infections/drug therapy ; Gentian Violet ; Humans ; Microbial Sensitivity Tests ; *Nanoparticles ; *Uropathogenic Escherichia coli ; }, abstract = {Peptide IDR1018 and chitosan nanoparticles (CNs) showed antimicrobial and anti-biofilm activity against bacteria. In this study, the antimicrobial effects of peptide IDR1018 and CNs were evaluated on 50 clinical isolates of uropathogenic Escherichia coli (UPEC) resistant to ciprofloxacin. Ion gelation method was applied for CNs synthesis. Scanning electron microscope (SEM) and dynamic light scattering (DLS) were utilized to evaluate the nanoparticles. Antimicrobial and synergistic activity of peptide IDR1018 and CNs with ciprofloxacin were evaluated by microtiter broth dilution method. The checkerboard test was used to investigate the antimicrobial effects of IDR1018 and CNS in combination with ciprofloxacin. Anti-biofilm effect of ciprofloxacin, peptide IDR1018, and CNs was evaluated using crystal violet method. Fourteen (28%), 21 (42%), and 15 (30%) of clinical isolates produced strong, moderate, and weak biofilm, respectively. The CNs were spherical and uniform under electron microscopy with an average diameter of 246 nm. The minimum inhibitory concentration (MIC) values were 16-128, 20-40, and 375-750 (µg/ml) for ciprofloxacin, peptide IDR1018, and CNs, respectively. Fractional inhibitory concentration (FIC) analysis indicated a synergistic effect of ciprofloxacin in combination with peptide IDR1018, but in combination with CNs, this antibiotic showed an additive effect. Our results revealed that peptide IDR1018 and CNs have antimicrobial properties on UPEC isolates. Biofilm inhibition and biofilm eradication of clinical isolate were shown by peptide IDR1018 and CNs in a concentration-dependent manner. The antimicrobial agents alone and in combination decreased the number of viable bacteria in the biofilms. Therefore, these components seem to be a treating approach against biofilm-forming UPEC isolates.}, } @article {pmid35728770, year = {2022}, author = {Abdulghani, M and Iram, R and Chidrawar, P and Bhosle, K and Kazi, R and Patil, R and Kharat, K and Zore, G}, title = {Proteomic profile of Candida albicans biofilm.}, journal = {Journal of proteomics}, volume = {265}, number = {}, pages = {104661}, doi = {10.1016/j.jprot.2022.104661}, pmid = {35728770}, issn = {1876-7737}, mesh = {*Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans/metabolism ; Chromatography, Liquid ; Fungal Proteins/metabolism ; Humans ; Proteomics ; Tandem Mass Spectrometry ; }, abstract = {Candida albicans biofilms are characterized by structural and cellular heterogeneity that confers antifungal resistance and immune evasion. Despite this, biofilm formation remains poorly understood. In this study, we used proteomic analysis to understand biofilm formation in C. albicans related to morphophysiological and architectural features. LC-MS/MS analysis revealed that 64 proteins were significantly modulated, of which 31 were upregulated and 33 were downregulated. The results indicate that metabolism (25 proteins), gene expression (13 proteins), stress response (7 proteins), and cell wall (5 proteins) composition are modulated. The rate of oxidative phosphorylation (OxPhos) and biosynthesis of UDP-N-acetylglucosamine, vitamin B6, and thiamine increased, while the rate of methionine biosynthesis decreased. There was a significant modification of the cell wall architecture due to higher levels of Sun41, Pir1 and Csh1 and increased glycosylation of proteins. It was observed that C. albicans induces hyphal growth by upregulating the expression of genes involved in cAMP-PKA and MAPK pathways. This study is significant in that it suggests an increase in OxPhos and alteration of cell wall architecture that could be contributing to the recalcitrance of C. albicans cells growing in biofilms. Nevertheless, a deeper investigation is needed to explore it further. SIGNIFICANCE: Candida sps is included in the list of pathogens with potential drug resistance threat due to the increased frequency especially colonization of medical devices, and tissues among the patients, in recent years. Significance of our study is that we are reporting traits like modulation in cell wall composition, amino acid and vitamin biosynthesis and importantly energy generation (OxPhos) etc. These traits could be conferring antifungal resistance, host immune evasion etc. and thus survival, in addition to facilitating biofilm formation. These findings are expected to prime the further studies on devising potent strategy against biofilm growth among the patients.}, } @article {pmid35728312, year = {2022}, author = {Zheng, P and Li, Y and Chi, Q and Cheng, Y and Jiang, X and Chen, D and Mu, Y and Shen, J}, title = {Structural characteristics and microbial function of biofilm in membrane-aerated biofilm reactor for the biodegradation of volatile pyridine.}, journal = {Journal of hazardous materials}, volume = {437}, number = {}, pages = {129370}, doi = {10.1016/j.jhazmat.2022.129370}, pmid = {35728312}, issn = {1873-3336}, mesh = {Biofilms ; *Bioreactors ; Pyridines ; *Waste Disposal, Fluid/methods ; Wastewater/chemistry ; }, abstract = {In order to avoid the serious air pollution caused by the volatilization of high recalcitrant pyridine, membrane-aerated biofilm reactor (MABR) with bubble-free aeration was used in this study, with the structural characteristics and microbial function of biofilm emphasized. The results showed that as high as 0.6 kg·m[-3]·d[-1] pyridine could be completely removed in MABR. High pyridine loading thickened the biofilm, but without obvious detachment observed. The distinct stratification of microbes and extracellular polymeric substances were shaped by elevated pyridine load, enhancing the structural heterogeneity of biofilm. The increased tryptophan-like substances as well as α-helix and β-sheet proportion in proteins stabilized the biofilm structure against high influent loading. Based on the identified intermediates, possible pyridine biodegradation pathways were proposed. Multi-omics analyses revealed that the metabolic pathways with initial hydroxylation and reduction reaction was enhanced at high pyridine loading. The functional genes were mainly associated with Pseudomonas and Delftia, might responsible for pyridine biodegradation. The results shed light on the effective treatment of wastewater containing recalcitrant pollutants such as pyridine via MABR.}, } @article {pmid35727518, year = {2022}, author = {Saygin, H and Baysal, A}, title = {Interaction of nanoplastics with simulated biological fluids and their effect on the biofilm formation.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {53}, pages = {80775-80786}, doi = {10.1007/s11356-022-21468-4}, pmid = {35727518}, issn = {1614-7499}, support = {2021/03//Istanbul Aydin University/ ; }, mesh = {Humans ; *Microplastics ; Saliva, Artificial ; *Plastics ; Biofilms ; }, abstract = {Over the last decade, it has become clear that the pollution by plastic debris presents global societal, environmental, and human health challenges. Moreover, humans are exposed to plastic particles in daily life and very limited information is available concerning human health, especially interactions with biological fluids. Therefore, the aim of this study is to investigate the interaction of plastic particles with simulated biological fluids (e.g., artificial saliva, artificial lysosomal fluid, phagolysosomal simulant fluid, and Gamble's solution) using various exposure stages (2 h to 80 h) and the effect of plastic particles on the formation of Staphylococcus aureus biofilms under simulated biological conditions. The plastic particles incubating various simulated biological fluids were characterized using surface functional groups, zeta potentials, and elemental composition. The results indicated that functional group indices (C-O, C = O, C-H, C = C, C-N, S = O, and OH) decreased compared to the control group during the incubation periods, except for the hydroxyl group index. The FTIR results showed that the hydroxyl group formed with the artificial lysosomal fluid, the phagolysosomal simulant fluid, and Gamble's solution. With the impact of the declining functional groups, the zeta potentials were more negative than in the control. Moreover, EDX results showed the release of the components in the particles with the interaction of simulated biological fluids as well as new components like P and Ca introduced to the particles. The biofilms were formed in the presence of nanoplastic particles under both controlled conditions and simulated biological conditions. The amount of biofilm formation was mainly affected by the surface characteristics under simulated biological conditions. In addition, the biofilm characteristics were influenced by the O/C and N/C ratios of the plastic particles with the impact of simulated biological fluids.}, } @article {pmid35724713, year = {2022}, author = {Xiong, H and Yang, G and Shan, X and Miao, L}, title = {Unveiling the effect of acetate on the interactions of functional bacteria in an anammox biofilm system.}, journal = {Chemosphere}, volume = {305}, number = {}, pages = {135408}, doi = {10.1016/j.chemosphere.2022.135408}, pmid = {35724713}, issn = {1879-1298}, mesh = {Acetates/metabolism ; *Ammonium Compounds/metabolism ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Nitrogen/analysis ; Oxidation-Reduction ; Sewage/microbiology ; }, abstract = {Biodegradable organics make an important impact on anaerobic ammonium oxidation (anammox) system. In this study, acetate was selected as a typical biodegradable organic, and its effect on the anammox biofilm system was comprehensively discussed from the macro and micro perspectives. Under a low influent concentration of acetate (<240 ± 10 mg/L), the best total nitrogen (TN) removal performance was 96%, but it decreased to 83% when the acetate concentration increased to 350 ± 20 mg/L. With the addition of acetate, the relative abundance of the family Brocadiaceae, which contains all known anammox bacteria, gradually increased from 7.97% to 12.79%, indicating that the presence of acetate promoted enrichment of anammox bacteria in the biofilm. Metagenomic analysis further demonstrated that an appropriate concentration of acetate helps to increase the abundances of the key enzymes related to nitrogen removal and enhance the metabolism of anammox and denitrification, thereby promoting the synergy of anammox and denitrifying bacteria. Hydrazine synthase (hzs), which is unique to the anammox process, was detected in association with the genera Candidatus Kuenenia, Candidatus Jettenia and Candidatus Brocadia, with its abundance increasing from 13268 (with no addition of acetate) to 19186 (with acetate addition of 240 ± 10 mg/L). This work provides a deeper understanding of the intrinsic interactions between functional bacteria in an anammox biofilm system.}, } @article {pmid35724257, year = {2022}, author = {Said, M and Hom, DB}, title = {Commentary on "Evidence of Biofilm and Persister Cell Formation in Revision Rhinoplasty" by Kao et al.}, journal = {Facial plastic surgery & aesthetic medicine}, volume = {24}, number = {3}, pages = {238-239}, doi = {10.1089/fpsam.2022.0118}, pmid = {35724257}, issn = {2689-3622}, mesh = {Anti-Bacterial Agents ; Biofilms ; Humans ; Reoperation ; *Rhinoplasty ; }, } @article {pmid35724255, year = {2022}, author = {Kao, WK and Faddis, B and Chole, RA and Davis, RE}, title = {Evidence of Biofilm and Persister Cell Formation in Revision Rhinoplasty.}, journal = {Facial plastic surgery & aesthetic medicine}, volume = {24}, number = {3}, pages = {233-238}, doi = {10.1089/fpsam.2021.0378}, pmid = {35724255}, issn = {2689-3622}, mesh = {Biofilms ; Humans ; Nose/surgery ; *Nose Deformities, Acquired/surgery ; Postoperative Complications/surgery ; Reoperation ; *Rhinoplasty/methods ; }, abstract = {Background: Postoperative rhinoplasty infection can lead to serious cosmetic deformity, loss of structural integrity to the nose, and functional deficiencies. Understanding the factors contributing to postoperative infection is important. Microbial biofilms and persister cells play an important role in health care-associated infections. The objective of this study is to identify microbial biofilm and persister cells in the nasal soft tissue of patients undergoing revision rhinoplasty. Methods: Fourteen patients undergoing rhinoplasty were recruited for this study. Nasal soft tissue was removed during rhinoplasty and preserved in 2% paraformaldehyde/2.5% glutaraldehyde. High-resolution images were then obtained from these nasal soft tissue samples. Results: Three samples were positive for the presence of microbial persister cells or biofilms. All samples came from patients undergoing revision rhinoplasty. These patients had between one to six previous rhinoplasty procedures and one patient had previous injectable nasal filler. Conclusions: Biofilms and persister cells are able to form in nasal soft tissue of revision rhinoplasty patients in the absence of an implant and may contribute to increased postoperative infection risk.}, } @article {pmid35723966, year = {2022}, author = {Austin, PD and Stapleton, P and Elia, M}, title = {Comparative effect of seven prophylactic locks to prevent biofilm biomass and viability in intravenous catheters.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {8}, pages = {2191-2198}, doi = {10.1093/jac/dkac181}, pmid = {35723966}, issn = {1460-2091}, support = {//Health Education England/ ; //National Institute for Health Research/ ; }, mesh = {Biofilms ; *Catheter-Related Infections/prevention & control ; Catheters ; Catheters, Indwelling ; Citrates/pharmacology ; *Escherichia coli ; Humans ; Sodium Chloride/pharmacology ; Staphylococcus epidermidis ; }, abstract = {BACKGROUND: Patients requiring long-term intravenous access are at risk of intraluminal catheter bloodstream infection. 'Prophylactic' locks aim to limit this risk but there is uncertainty regarding the most effective lock.

OBJECTIVES: To develop a novel technique intended to replicate clinical procedures to compare the effectiveness of various 'prophylactic' locks against biofilm biomass ('biomass') formation and biofilm viability ('viability') of Escherichia coli and Staphylococcus epidermidis in intravenous catheters.

METHODS: For 10 consecutive days 106 cfu/mL E. coli NCTC 10418 and S. epidermidis ATCC 12228 were separately cultured in single lumen 9.6 French silicone tunnelled and cuffed catheters. These were flushed with 0.9% w/v sodium chloride using a push-pause technique before and after instillation of seven 'prophylactic' locks (water, ethanol, sodium chloride, heparinized sodium chloride, citrate, taurolidine plus citrate, and taurolidine; each in triplicate) for 6 h daily. Intraluminal 'biomass' and 'viability' were quantified using crystal violet staining and flush culture, respectively.

RESULTS: The reduction of 'biomass' and 'viability' depended on both agent and species. Citrate was least effective against E. coli 'viability' and 'biomass' but most effective against S. epidermidis 'viability', and taurolidine was most effective against E. coli 'biomass' and 'viability' but least effective against S. epidermidis 'viability'. 'Biomass' and 'viability' were significantly correlated in E. coli between (r = 0.997, P < 0.001) and within (r = 0.754, P = 0.001) interventions, but not in S. epidermidis.

CONCLUSIONS: A novel technique found the effect of 'prophylactic' agents in reducing 'biomass' and 'viability' varied by species. The choice of agent depends on the most likely infecting organism.}, } @article {pmid35722343, year = {2022}, author = {Dong, K and Feng, X and Yao, Y and Zhu, Z and Lin, H and Zhang, X and Wang, D and Li, H}, title = {Nitrogen Removal From Nitrate-Containing Wastewaters in Hydrogen-Based Membrane Biofilm Reactors via Hydrogen Autotrophic Denitrification: Biofilm Structure, Microbial Community and Optimization Strategies.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {924084}, pmid = {35722343}, issn = {1664-302X}, abstract = {The hydrogen-based membrane biofilm reactor (MBfR) has been widely applied in nitrate removal from wastewater, while the erratic fluctuation of treatment efficiency is in consequence of unstable operation parameters. In this study, hydrogen pressure, pH, and biofilm thickness were optimized as the key controlling parameters to operate MBfR. The results of 653.31 μm in biofilm thickness, 0.05 MPa in hydrogen pressure and pH in 7.78 suggesting high-efficiency NO 3 - - N removal and the NO 3 - - N removal flux was 1.15 g·m[-2] d[-1]. 16S rRNA gene analysis revealed that Pseudomonas, Methyloversatilis, Thauera, Nitrospira, and Hydrogenophaga were the five most abundant bacterial genera in MBfRs after optimization. Moreover, significant increases of Pseudomonas relative abundances from 0.36 to 9.77% suggested that optimization could effectively remove nitrogen from MBfRs. Membrane pores and surfaces exhibited varying degrees of calcification during stable operation, as evinced by Ca[2+] precipitation adhering to MBfR membrane surfaces based on scanning electron microscopy (SEM), atomic force microscopy (AFM) analyses. Scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) analyses also confirmed that the primary elemental composition of polyvinyl chloride (PVC) membrane surfaces after response surface methodology (RSM) optimization comprised Ca, O, C, P, and Fe. Further, X-ray diffraction (XRD) analyses indicated the formation of Ca5F(PO4)3 geometry during the stable operation phase.}, } @article {pmid35722322, year = {2022}, author = {Pombo, JP and Ebenberger, SP and Müller, AM and Wolinski, H and Schild, S}, title = {Impact of Gene Repression on Biofilm Formation of Vibrio cholerae.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {912297}, pmid = {35722322}, issn = {1664-302X}, abstract = {Vibrio cholerae, the etiological agent of cholera, is a facultative intestinal pathogen which can also survive in aquatic ecosystems in the form of biofilms, surface-associated microbial aggregates embedded in an extracellular matrix, which protects them from predators and hostile environmental factors. Biofilm-derived bacteria and biofilm aggregates are considered a likely source for cholera infections, underscoring the importance of V. cholerae biofilm research not just to better understand bacterial ecology, but also cholera pathogenesis in the human host. While several studies focused on factors induced during biofilm formation, genes repressed during this persistence stage have been fairly neglected. In order to complement these previous studies, we used a single cell-based transcriptional reporter system named TetR-controlled recombination-based in-biofilm expression technology (TRIBET) and identified 192 genes to be specifically repressed by V. cholerae during biofilm formation. Predicted functions of in-biofilm repressed (ibr) genes range from metabolism, regulation, surface association, transmembrane transport as well as motility and chemotaxis. Constitutive (over)-expression of these genes affected static and dynamic biofilm formation of V. cholerae at different stages. Notably, timed expression of one candidate in mature biofilms induced their rapid dispersal. Thus, genes repressed during biofilm formation are not only dispensable for this persistence stage, but their presence can interfere with ordered biofilm development. This work thus contributes new insights into gene silencing during biofilm formation of V. cholerae.}, } @article {pmid35718788, year = {2022}, author = {Gupta, KK and Sharma, KK and Chandra, H}, title = {Micrococcus luteus strain CGK112 isolated from cow dung demonstrated efficient biofilm-forming ability and degradation potential toward high-density polyethylene (HDPE).}, journal = {Archives of microbiology}, volume = {204}, number = {7}, pages = {402}, pmid = {35718788}, issn = {1432-072X}, mesh = {Animals ; Bacteria/metabolism ; Biodegradation, Environmental ; Biofilms ; Carbon/metabolism ; Cattle ; Female ; *Micrococcus luteus/genetics/metabolism ; *Polyethylene/metabolism ; RNA, Ribosomal, 16S/genetics/metabolism ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Biodegradation is the most promising environmentally sustainable method that offers a significant opportunity with minimal negative environmental consequences while searching for solutions to this global problem of plastic pollution that has now spread to almost everywhere in the entire world. In the present work, HDPE-degrading bacterial strain CGK112 was isolated from the fecal matter of a cow. The bacterial strain was identified as Micrococcus luteus CGK112 by 16S rRNA sequence coding analysis. Significant weight loss, i.e., 3.85% was recorded in the HDPE film treated with strain CGK112 for 90 days. The surface micromorphology was examined using FE-SEM, which revealed spectacular bacterial colonization as well as structural deformation. Furthermore, the EDX study indicated a significant decrease in the atomic percentage of carbon content, whereas FTIR analysis confirmed functional groups alternation as well as an increase in the carbonyl index which can be attributed to the metabolic activity of biofilm. Our findings provide insight into the capacity of our strain CGK112 to colonize and utilize HDPE as a single carbon source, thus promoting its degradation.}, } @article {pmid35718173, year = {2022}, author = {Alrashed, W and Chandra, R and Abbott, T and Lee, HS}, title = {Nitrite reduction using a membrane biofilm reactor (MBfR) in a hypoxic environment with dilute methane under low pressures.}, journal = {The Science of the total environment}, volume = {841}, number = {}, pages = {156757}, doi = {10.1016/j.scitotenv.2022.156757}, pmid = {35718173}, issn = {1879-1026}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; Denitrification ; *Methane ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater/microbiology ; }, abstract = {Methane-based membrane biofilm reactors (MBfRs) can be an effective solution for nitrogen control in wastewater, but there is limited information on nitrite reduction for dilute wastewater (e.g., municipal wastewater) in hypoxic MBfRs. This study assessed the impacts of dilute (20 %), low-pressure methane (0.35-2.41 kPa) applied to MBfRs at hydraulic retention times (HRTs) of 2-12 h on nitrite removals, dissolved methane concentrations, and the resulting changes in the microbial community. High nitrite flux along with rapid and virtually complete (>99 %) nitrite removals were observed at methane pressures of 1.03-2.41 kPa at HRTs above 4 h, despite the use of diluted methane gas for the MBfR. The lowest methane pressure (0.35 kPa) was also able to achieve up to 98 % nitrite removals but required HRTs of up to 12 h. All scenarios had low dissolved methane concentrations (<10 mg/L), indicating that dilute methane at low supply pressures can effectively remove nitrite while meeting dissolved methane guidelines in treated effluent. Methylococcus genus was the key bacterium in MBfR biofilm grown at different HRTs and methane pressures, along with Methylocystis and other heterotrophic denitrifiers (Terrimonas and Hyphomicrobium). This study indicates that methane-based denitrification MBfRs can be a valuable tool to meet nitrogen limits for dilute wastewater coupled to partial nitrification, while limiting the release of methane to the environment.}, } @article {pmid35718162, year = {2022}, author = {Jia, J and Xue, X and Guan, Y and Fan, X and Wang, Z}, title = {Biofilm characteristics and transcriptomic profiling of Acinetobacter johnsonii defines signatures for planktonic and biofilm cells.}, journal = {Environmental research}, volume = {213}, number = {}, pages = {113714}, doi = {10.1016/j.envres.2022.113714}, pmid = {35718162}, issn = {1096-0953}, mesh = {Acinetobacter ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; *Plankton ; Tetracycline/pharmacology ; *Transcriptome ; }, abstract = {Most bacteria in the natural environment have a biofilm mode of life, which is intrinsically tolerant to antibiotics. While until now, the knowledge of biofilm formation by Acinetobacter johnsonii is not well understood. In this study, the characteristics and the effect of a sub-inhibitory concentration of antibiotic on A. johnsonii biofilm and planktonic cells were determined. We discovered a positive relationship between biofilm formation and tetracycline resistance, and biofilms rapidly evolve resistance to tetracycline they are treated with. Persister cells commonly exist in both planktonic and biofilm cells, with a higher frequency in the latter. Further transcriptomic analysis speculates that the overexpression of multidrug resistance genes and stress genes were mainly answered to sub lethal concentration of tetracycline in planktonic cells, and the lower metabolic levels after biofilm formation result in high resistance level of biofilm cells to tetracycline. Altogether, these data suggest that A. johnsonii can adjust its phenotype when grown as biofilm and change its metabolism under antibiotic stress, and provide implications for subsequent biofilm control.}, } @article {pmid35717506, year = {2022}, author = {Crescente, CL and de Sousa, ET and Lima-Holanda, AT and Steiner-Oliveira, C and Nobre-Dos-Santos, M}, title = {Biofilm accumulation and sucrose rinse modulate calcium and fluoride bioavailability in the saliva of children with early childhood caries.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {10283}, pmid = {35717506}, issn = {2045-2322}, mesh = {Biofilms ; Biological Availability ; Calcium/pharmacology ; Calcium, Dietary/pharmacology ; Child ; Child, Preschool ; *Dental Caries ; Dental Caries Susceptibility ; Female ; *Fluorides/pharmacology ; Humans ; Male ; Phosphates/pharmacology ; Saliva ; Sucrose/pharmacology ; }, abstract = {This study aimed at investigating the combined effect of biofilm accumulation and 20% sucrose rinse on the modulation of calcium (Ca[2+]), phosphate (Pi), and fluoride (F[-]) bioavailability in the saliva of children with early childhood caries (ECC). Fifty-six preschoolers of both genders were evaluated according to caries experience and activity: caries-free (CF, n = 28) and with ECC (n = 28) and then, submitted to biofilm intervention (biofilm accumulation). In each situation, saliva samples were collected before and five minutes after a 20% sucrose rinse to determine the concentrations of Ca[2+], Pi, and F[-]. Calcium concentration was significantly lower in the biofilm accumulation situation compared to the situation of biofilm mechanical control (p ≤ 0.01), except for CF children after sucrose rinse. Biofilm accumulation increased salivary calcium concentration in children with ECC after sucrose rinse (p = 0.04), whereas mechanical biofilm control reduced it in both groups (p = 0.000). Phosphate concentration was influenced by mechanical control of biofilm in CF children (p = 0.03). The fluoride bioavailability was reduced by sucrose rinse and biofilm accumulation in CF and ECC children (p ≤ 0.002). In conclusion, the combined effect of biofilm accumulation and sucrose rinse modifies the bioavailability of calcium and fluoride in the saliva of children with early childhood caries.}, } @article {pmid35717090, year = {2022}, author = {Pan, L and Wan, Z and Feng, Q and Wang, J and Xiong, J and Wang, S and Zhu, H and Chen, G}, title = {Biofilm response and removal via the coupling of visible-light-driven photocatalysis and biodegradation in an environment of sulfamethoxazole and Cr(VI).}, journal = {Journal of environmental sciences (China)}, volume = {122}, number = {}, pages = {50-61}, doi = {10.1016/j.jes.2021.09.038}, pmid = {35717090}, issn = {1001-0742}, mesh = {Biofilms ; Catalysis ; Chromium ; *Environmental Pollutants ; *Sulfamethoxazole ; Titanium ; }, abstract = {The widespread contamination of water systems with antibiotics and heavy metals has gained much attention. Intimately coupled visible -light-responsive photocatalysis and biodegradation (ICPB) provides a novel approach for removing such mixed pollutants. In ICPB, the photocatalysis products are biodegraded by a protected biofilm, leading to the mineralization of refractory organics. In the present study, the ICPB approach exhibited excellent photocatalytic activity and biodegradation, providing up to ∼1.27 times the degradation rate of sulfamethoxazole (SMX) and 1.16 times the Cr(VI) reduction rate of visible-light-induced photocatalysis . Three-dimensional fluorescence analysis demonstrated the synergistic ICPB effects of photocatalysis and biodegradation for removing SMX and reducing Cr(VI). In addition, the toxicity of the SMX intermediates and Cr(VI) in the ICPB process significantly decreased. The use of MoS2/CoS2 photocatalyst accelerated the separation of electrons and holes, with•O2[-] and h[+] attacking SMX and e[-] reducing Cr(VI), providing an effective means for enhancing the removal and mineralization of these mixed pollutants via the ICPB technique. The microbial community results demonstrate that bacteria that are conducive to pollutant removal are were enriched by the acclimation and ICPB operation processes, thus significantly improving the performance of the ICPB system.}, } @article {pmid35717079, year = {2022}, author = {Arabgol, R and Vanrolleghem, PA and Delatolla, R}, title = {Influence of MBBR carrier geometrical properties and biofilm thickness restraint on biofilm properties, effluent particle size distribution, settling velocity distribution, and settling behaviour.}, journal = {Journal of environmental sciences (China)}, volume = {122}, number = {}, pages = {138-149}, doi = {10.1016/j.jes.2021.09.029}, pmid = {35717079}, issn = {1001-0742}, mesh = {*Biofilms ; *Bioreactors ; Particle Size ; Waste Disposal, Fluid/methods ; }, abstract = {The relatively poor settling characteristics of particles produced in moving bed biofilm reactor (MBBR) outline the importance of developing a fundamental understanding of the characterization and settleability of MBBR-produced solids. The influence of carrier geometric properties and different levels of biofilm thickness on biofilm characteristics, solids production, particle size distribution (PSD), and particle settling velocity distribution (PSVD) is evaluated in this study. The analytical ViCAs method is applied to the MBBR effluent to assess the distribution of particle settling velocities. This method is combined with microscopy imaging to relate particle size distribution to settling velocity. Three conventionally loaded MBBR systems are studied at a similar loading rate of 6.0 g/(m[2] •day) and with different carrier types. The AnoxK™ K5 carrier, a commonly used carrier, is compared to so-called thickness-restraint carriers, AnoxK™ Z-carriers that are newly designed carriers to limit the biofilm thickness. Moreover, two levels of biofilm thickness, 200 μm and 400 μm, are studied using AnoxK™ Z-200 and Z-400 carriers. Statistical analysis confirms that K5 carriers demonstrated a significantly different biofilm mass, thickness, and density, in addition to distinct trends in PSD and PSVD in comparison with Z-carriers. However, in comparison of thickness-restraint carriers, Z-200 carrier results did not vary significantly compared to the Z-400 carrier. The K5 carriers showed the lowest production of suspended solids (0.7 ± 0.3 g-TSS/day), thickest biofilm (281.1 ± 8.7 µm) and lowest biofilm density (65.0 ± 1.5 kg/m[3]). The K5 effluent solids also showed enhanced settling behaviour, consisting of larger particles with faster settling velocities.}, } @article {pmid35716164, year = {2022}, author = {Petrovic, M and Bonvin, D and Todic, J and Zivkovic, R and Randjelovic, M and Arsenijevic, VA and Ebersold, MM and Otasevic, S}, title = {Surface modification of poly(methyl-methacrylate) with farnesol to prevent Candida biofilm formation.}, journal = {Letters in applied microbiology}, volume = {75}, number = {4}, pages = {982-990}, doi = {10.1111/lam.13772}, pmid = {35716164}, issn = {1472-765X}, mesh = {Agar ; Antifungal Agents/pharmacology ; Biofilms ; Candida ; Candida albicans ; Dental Materials ; *Farnesol/pharmacology ; Methacrylates ; *Polymethyl Methacrylate/chemistry ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; }, abstract = {Candida albicans promotes biofilm formation on dentures, which compromises the use of poly(methyl-methacrylate) (PMMA) as a dental material. Farnesol (FAR), a natural compound that prevents C. albicans filamentation and biofilm formation, was incorporated into the PMMA matrix, to obtain antifungal PMMA_FAR materials. The tested concentrations (0·0125% and 0·4%) of FAR, 24 h after incubation on YPD agar, inhibited filamentation of C. albicans. PMMA was modified with different FAR concentrations (3-12%), and physicochemical properties, antifungal activity and cytotoxicity of these modified materials (PMMA_FAR) were tested. The presence of FAR in PMMA_FAR composites was verified by Fourier-transform infrared spectroscopy (FT-IR). Incorporation of FAR into the polymeric matrix significantly decreased hydrophilicity at all tested concentrations and significantly reduced biofilm and planktonic cells metabolic activity in the early stage of biofilm formation at ≥6% FAR in PMMA. PMMA_FAR composites with <9% FAR were non-toxic. Modification of PMMA with FAR is a good strategy for reducing C. albicans biofilm formation on dentures.}, } @article {pmid35714383, year = {2022}, author = {Benedek, T and Pápai, M and Gharieb, K and Bedics, A and Táncsics, A and Tóth, E and Daood, H and Maróti, G and Wirth, R and Menashe, O and Bóka, K and Kriszt, B}, title = {Nocardioides carbamazepini sp. nov., an ibuprofen degrader isolated from a biofilm bacterial community enriched on carbamazepine.}, journal = {Systematic and applied microbiology}, volume = {45}, number = {4}, pages = {126339}, doi = {10.1016/j.syapm.2022.126339}, pmid = {35714383}, issn = {1618-0984}, mesh = {*Actinomycetales ; Bacterial Typing Techniques ; Base Composition ; Biofilms ; Carbamazepine ; DNA, Bacterial/genetics ; Fatty Acids/analysis ; Ibuprofen ; *Nocardioides ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Soil Microbiology ; Vitamin K 2/chemistry ; }, abstract = {From the metagenome of a carbamazepine amended selective enrichment culture the genome of a new to science bacterial species affiliating with the genus Nocardioides was reconstructed. From the same enrichment an aerobic actinobacterium, strain CBZ_1[T], sharing 99.4% whole-genome sequence similarity with the reconstructed Nocardioides sp. bin genome was isolated. On the basis of 16S rRNA gene sequence similarity the novel isolate affiliated to the genus Nocardioides, with the closest relatives Nocardioides kongjuensis DSM19082[T] (98.4%), Nocardioides daeguensis JCM17460[T] (98.4%) and Nocardioides nitrophenolicus DSM15529[T] (98.2%). Using a polyphasic approach it was confirmed that the isolate CBZ_1[T] represents a new phyletic lineage within the genus Nocardioides. According to metagenomic, metatranscriptomic studies and metabolic analyses strain CZB_1[T] was abundant in both carbamazepine and ibuprofen enrichments, and harbors biodegradative genes involved in the biodegradation of pharmaceutical compounds. Biodegradation studies supported that the new species was capable of ibuprofen biodegradation. After 7 weeks of incubation, in mineral salts solution supplemented with glucose (3 g l[-1]) as co-substrate, 70% of ibuprofen was eliminated by strain CBZ_1[T] at an initial conc. of 1.5 mg l[-1]. The phylogenetic, phenotypic and chemotaxonomic data supported the classification of strain CBZ_1[T] to the genus Nocardioides, for which the name Nocardioides carbamazepini sp. nov. (CBZ_1[T] = NCAIM B.0.2663 = LMG 32395) is proposed. To the best of our knowledge, this is the first study that reports simultaneous genome reconstruction of a new to science bacterial species using metagenome binning and at the same time the isolation of the same novel bacterial species.}, } @article {pmid35713471, year = {2022}, author = {Liu, M and Huang, L and Xu, X and Wei, X and Yang, X and Li, X and Wang, B and Xu, Y and Li, L and Yang, Z}, title = {Copper Doped Carbon Dots for Addressing Bacterial Biofilm Formation, Wound Infection, and Tooth Staining.}, journal = {ACS nano}, volume = {16}, number = {6}, pages = {9479-9497}, doi = {10.1021/acsnano.2c02518}, pmid = {35713471}, issn = {1936-086X}, mesh = {Humans ; *Copper/pharmacology ; Carbon ; Hydrogen Peroxide ; Staphylococcus aureus ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Escherichia coli ; *Wound Infection ; Staining and Labeling ; }, abstract = {Oral infectious diseases and tooth staining, the main challenges of dental healthcare, are inextricably linked to microbial colonization and the formation of pathogenic biofilms. However, dentistry has so far still lacked simple, safe, and universal prophylactic options and therapy. Here, we report copper-doped carbon dots (Cu-CDs) that display enhanced catalytic (catalase-like, peroxidase-like) activity in the oral environment for inhibiting initial bacteria (Streptococcus mutans) adhesion and for subsequent biofilm eradication without impacting the surrounding oral tissues via oxygen (O2) and reactive oxygen species (ROS) generation. Especially, Cu-CDs exhibit strong affinity for lipopolysaccharides (LPS) and peptidoglycans (PGN), thus conferring them with excellent antibacterial ability against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), such that they can prevent wound purulent infection and promoting rapid wound healing. Additionally, the Cu-CDs/H2O2 system shows a better performance in tooth whitening, compared with results obtained with other alternatives, e.g., CDs and clinically used H2O2, particularly its negligible enamel and dentin destruction. It is anticipated that the biocompatible Cu-CDs presented in this work are a promising nano-mouthwash for eliminating oral pathogenic biofilms, prompting wound healing as well as tooth whitening, highlighting their significance in oral health management.}, } @article {pmid35711752, year = {2022}, author = {Fei, P and Jing, H and Ma, Y and Dong, G and Chang, Y and Meng, Z and Jiang, S and Xie, Q and Li, S and Chen, X and Yang, W}, title = {Cronobacter spp. in Commercial Powdered Infant Formula Collected From Nine Provinces in China: Prevalence, Genotype, Biofilm Formation, and Antibiotic Susceptibility.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {900690}, pmid = {35711752}, issn = {1664-302X}, abstract = {The purpose of this study was to investigate the prevalence of Cronobacter spp. in commercial powdered infant formula (PIF) from nine provinces in China from March 2018 to September 2020, and to reveal the genotype, biofilm-forming ability, and antibiotic susceptibility of these isolates. A total of 27 Cronobacter strains, consisting of 22 Cronobacter sakazakii strains, 3 Cronobacter malonaticus strains, 1 Cronobacter turicensis strain, and 1 Cronobacter dublinensis strain, were isolated from 3,600 commercial PIF samples with a prevalence rate of 0.75%. Compared with the other 8 provinces, PIF from Shaanxi province had a higher prevalence rate (1.25%) of Cronobacter spp. These isolates were divided into 14 sequence types (STs), and 6 Cronobacter serotypes. The main Cronobacter STs were ST4, ST1, and ST64, and the dominant Cronobacter serotype was C. sakazakii serotype O2. Approximately 88.89% of Cronobacter isolates had a strong ability (OD595 > 1) to form biofilms on tinplate, among which the strains with ST4 were more dominant. All isolates were susceptible to ampicillin-sulbactam, ceftriaxone, cefotaxime, sulfadiazine, sulfadoxine, trimethoprim-sulfamethoxazole, gentamicin, tetracycline, ciprofloxacin, and colistin, while 55.56 and 96.30% isolates were resistant to cephalothin and vancomycin, respectively. Taken together, our findings highlighted the contamination status and characterization of Cronobacter spp. in commercial PIF from nine provinces of China, and provided guidance for the effective prevention and control of this pathogen in the production of PIF.}, } @article {pmid35709937, year = {2022}, author = {Aleksić, A and Stojanović-Radić, Z and Harmanus, C and Kuijper, EJ and Stojanović, P}, title = {In vitro anti-clostridial action and potential of the spice herbs essential oils to prevent biofilm formation of hypervirulent Clostridioides difficile strains isolated from hospitalized patients with CDI.}, journal = {Anaerobe}, volume = {76}, number = {}, pages = {102604}, doi = {10.1016/j.anaerobe.2022.102604}, pmid = {35709937}, issn = {1095-8274}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Clostridioides ; *Clostridioides difficile ; *Clostridium Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; *Oils, Volatile/pharmacology ; *Origanum ; Ribotyping ; Spices ; }, abstract = {BACKGROUND: Clostridioides difficile is the most common causative agent of antibiotic-acquired diarrhea in hospitalized patients associated with substantial morbidity and mortality. The global epidemic of CDI (Clostridioides difficile infection) began in the early 20th century with the emergence of the hypervirulent and resistant ribotype 027 strains, and requires an urgent search for new therapeutic agents.

OBJECTIVE: The aim of this study is to investigate the antibacterial activity of the three essential oils isolated from spice herbs (wild oregano, garlic and black pepper) against C. difficile clinical isolates belonging to 6 different PCR ribotypes and their potential inhibitory effect on the biofilm production in in vitro conditions.

RESULTS: Wild oregano essential oil showed strong inhibitory activity in concentrations 0.02-1.25 mg/mL and bactericidal activity in concentrations from 0.08 to 10 mg/mL. Garlic essential oil was effective in the concentration range of 0.02-40 mg/mL, and 0.16 - > 40 mg/mL. MIC and MBC for black pepper oil ranged from 0.04 to 40 mg/mL, and 0.08 - > 40 mg/mL, respectively. All the tested oils reduced in vitro biofilm production, with the best activity of oregano oil.

CONCLUSION: Essential oils of wild oregano, black pepper and garlic are candidates for adjunctive therapeutics in the treatment of CDI. Oregano oil should certainly be preferred due to the lack of selectivity of action in relation to the ribotype, the strength of the produced biofilm and/or antibiotic-susceptibility patterns.}, } @article {pmid35709929, year = {2022}, author = {Rajivgandhi, G and Ramachandran, G and Chackaravarthi, G and Chelliah, CK and Maruthupandy, M and Quero, F and Al-Mekhlafi, FA and Wadaan, MA and Li, WJ}, title = {Preparation of antibacterial Zn and Ni substituted cobalt ferrite nanoparticles for efficient biofilm eradication.}, journal = {Analytical biochemistry}, volume = {653}, number = {}, pages = {114787}, doi = {10.1016/j.ab.2022.114787}, pmid = {35709929}, issn = {1096-0309}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Cobalt/chemistry ; Ferric Compounds ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; *Metal Nanoparticles/chemistry ; *Nanoparticles/chemistry ; Nickel/chemistry ; Oxides/chemistry ; X-Ray Diffraction ; Zinc/chemistry ; }, abstract = {Zinc (Zn) and, alternatively, nickel (Ni) substituted cobalt ferrite (CF) nanoparticles (NPs) were prepared by sol-gel method. X-ray diffraction analysis revealed the formation of cubic structure of cobalt ferrite. FTIR analysis confirmed the vibrational band located at 550-580 cm[-1] that belongs to the M - O bond (M = Ni, and Zn). The alteration of the surface morphology of CF after the addition of Zn and Ni ions was observed from scanning electron microscopic images. The additional peaks in the energy dispersive X-ray diffraction (EDX) analysis spectra were found to correspond to Zn and Ni. The presence of Zn and, alternatively, Ni ions enhanced the biocidal properties of CF NPs against gram negative organisms, in a concentration and time-dependent manner. Furthermore, exposure to CF, CF-Zn and CF-Ni NPs decreased metabolic activity due to the damage of extra polymorphic substances, live/dead cell variation, architecture and surface integrity of the cells. Altogether, the present investigation provides the basis of metal ion substituted metal oxide NPs as anti-biofilm agents against gram-positive and gram-negative bacteria.}, } @article {pmid35709560, year = {2022}, author = {de Siqueira, VM and da Silva, BGM and Passos, JCDS and Pinto, AP and da Rocha, JBT and Alberto-Silva, C and Costa, MS}, title = {(MeOPhSe)2, a synthetic organic selenium compound, inhibits virulence factors of Candida krusei: Adherence to cervical epithelial cells and biofilm formation.}, journal = {Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS)}, volume = {73}, number = {}, pages = {127019}, doi = {10.1016/j.jtemb.2022.127019}, pmid = {35709560}, issn = {1878-3252}, mesh = {*Antifungal Agents/chemistry/pharmacology ; Benzene Derivatives ; Biofilms ; Candida ; Candida albicans ; Epithelial Cells ; Microbial Sensitivity Tests ; Organoselenium Compounds ; Pichia ; *Selenium/metabolism/pharmacology ; Virulence Factors/metabolism/pharmacology ; }, abstract = {BACKGROUND: Systemic candidiasis is produced by Candida albicans or non-albicans Candida species, opportunistic fungi that produce both superficial and invasive infections. Despite the availability of a wide range of antifungal agents for the treatment of candidiasis, failure of therapy is observed frequently, which opens new avenues in the field of alternative therapeutic strategies.

METHODS: The effects of p,p'-methoxyl-diphenyl diselenide [(MeOPhSe)2], a synthetic organic selenium (organochalcogen) compound, were investigated on virulence factors of C. krusei and compared with its antifungal effects on the virulence factors related to adhesion to cervical epithelial cell surfaces with C. albicans.

RESULTS: (MeOPhSe)2, a compound non-toxic in epithelial (HeLa) and fibroblastic (Vero) cells, inhibited the growth in a dose-dependent manner and changed the kinetics parameters of C. krusei and, most importantly, extending the duration of lag phase of growth, inhibiting biofilm formation, and changing the structure of biofilm. Also, (MeOPhSe)2 reduced C. albicans and C. krusei adherence to cervical epithelial cells, an important factor for the early stage of the Candida-host interaction. The reduction was 37.24 ± 2.7 % in C. krusei (p = 0.00153) and 32.84 ± 3.2 % in C. albicans (p = 0.0072) at 20 µM (MeOPhSe)2, and the effect is in a concentration-dependent manner. Surprisingly, the antifungal potential on adhesion was similar between both species, indicating the potential of (MeOPhSe)2 as a promising antifungal drug against different Candida infections.

CONCLUSION: Overall, we demonstrated the potential of (MeOPhSe)2 as an effective antifungal drug against the virulence factors of Candida species.}, } @article {pmid35708833, year = {2022}, author = {Deepika, G and Subbarayadu, S and Chaudhary, A and Sarma, PVGK}, title = {Dibenzyl (benzo [d] thiazol-2-yl (hydroxy) methyl) phosphonate (DBTMP) showing anti-S. aureus and anti-biofilm properties by elevating activities of serine protease (SspA) and cysteine protease staphopain B (SspB).}, journal = {Archives of microbiology}, volume = {204}, number = {7}, pages = {397}, pmid = {35708833}, issn = {1432-072X}, mesh = {Biofilms ; Cysteine ; *Cysteine Proteases/genetics/metabolism ; *Organophosphonates/pharmacology ; Serine Endopeptidases/genetics/metabolism ; Serine Proteases/genetics ; Staphylococcus aureus/genetics/metabolism ; }, abstract = {Staphylococcus aureus biofilms are the pathogenic factor in the spread of infection and are more pronounced in multidrug-resistant strains of S. aureus, where high expression of proteases is observed. Among various proteases, Serine protease (SspA) and cysteine protease Staphopain B (SspB) are known to play a key role in the biofilm formation and removal of biofilms. In earlier studies, we have reported Dibenzyl (benzo [d] thiazol-2-yl (hydroxy) methyl) phosphonate (DBTMP) exhibits anti-S. aureus and anti-biofilm properties by elevating the expression of the protease. In this study, the effect of DBTMP on the activities of SspA, and SspB of S. aureus was evaluated. The SspA and SspB genes of S. aureus ATCC12600 were sequenced (Genbank accession numbers: MZ456982 and MW574006). In S. aureus active SspA is formed by proteolytic cleavage of immature SspA, to get this mature SspA (mSspA), we have PCR amplified the mSspA sequence from the SspA gene. The mSspA and SspB genes were cloned, expressed, and characterized. The pure recombinant proteins rSspB and rmSspA exhibited a single band in SDS-PAGE with a molecular weight of 40 and 30 KD, respectively. The activities of rmSspA and rSspB are 32.33 and 35.45 Units/mL correspondingly. DBTMP elevated the activities of rmSspA and rSspB by docking with respective enzymes. This compound disrupted the biofilms formed by the multidrug-resistant strains of S. aureus and further prevented biofilm formation. These findings explain that DBTMP possesses anti-S. aureus and anti-biofilm features.}, } @article {pmid35707890, year = {2022}, author = {Lim, H and Chung, JH and Park, Y and Baek, N and Seo, Y and Park, H and Cho, YK and Jung, D and Han, DH}, title = {Inner surface modification of ureteral stent polyurethane tubes based by plasma-enhanced chemical vapor deposition to reduce encrustation and biofilm formation.}, journal = {Biofouling}, volume = {38}, number = {5}, pages = {482-492}, doi = {10.1080/08927014.2022.2087513}, pmid = {35707890}, issn = {1029-2454}, mesh = {Biofilms ; Gases ; *Polyurethanes/chemistry ; Stents ; *Ureter ; }, abstract = {Encrustation and/or biofilm formation in ureteral stents are major causes of obstruction and reduce the lifetime of a ureteral stent. In this study, the inner surfaces of polyurethane (PU) tubes (inner and outer diameters of 1.2 and 2.0 mm, respectively) were reformed with Ar, O2, and C2H2 gases using specialized plasma-enhanced chemical vapor deposition techniques for the first time. Then, the modified PU tubes were immersed in urine for 15 days, and the characteristics of the inner surfaces were analyzed. Depending on the modification procedure, the corresponding inner surface exhibited different chemical properties and different rates of encrustation and biofilm formation. For a hydrophilic surface treated with Ar and O2, encrustation and biofilm formation increased, while for the C2H2 coating, the development of encrustation and biofilm reduced by more than five times compared with the untreated bare PU tube. This study demonstrated that inner plasma surface modification of ureteral stents greatly enhances resistance to encrustation and biofilm formation.}, } @article {pmid35707153, year = {2022}, author = {Consoli, GML and Granata, G and Ginestra, G and Marino, A and Toscano, G and Nostro, A}, title = {Antibacterial Nanoassembled Calix[4]arene Exposing Choline Units Inhibits Biofilm and Motility of Gram Negative Bacteria.}, journal = {ACS medicinal chemistry letters}, volume = {13}, number = {6}, pages = {916-922}, pmid = {35707153}, issn = {1948-5875}, abstract = {The high incidence of antibiotic resistance and biofilm-associated infections is still a major cause of morbidity and mortality and triggers the need for new antimicrobial drugs and strategies. Nanotechnology is an emerging approach in the search for novel antimicrobial agents. The aim of this study was to investigate the inherent antibacterial effects of a self-assembling amphiphilic choline-calix[4]arene derivative (Chol-Calix) against Gram negative bacteria. Chol-Calix showed activity against Escherichia coli and Pseudomonas aeruginosa, including antibiotic-resistant strains, and affected the bacterial biofilm and motility. The activity is likely related to the amphipathicity and cationic surface of Chol-Calix nanoassembly that can establish large contact interactions with the bacterial surface. Chol-Calix appears to be a promising candidate in the search for novel nanosized nonconventional antimicrobials.}, } @article {pmid35704984, year = {2022}, author = {Nosrati, M and Ranjbar, R}, title = {Investigation of the antibacterial and biofilm inhibitory activities ofPrangos acaulis(DC.) Bornm in nanoparticulated formulation.}, journal = {Nanotechnology}, volume = {33}, number = {38}, pages = {}, doi = {10.1088/1361-6528/ac78f1}, pmid = {35704984}, issn = {1361-6528}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Chitosan/pharmacology ; *Nanoparticles ; }, abstract = {Here in, a chitosan-based nanoformulation ofP.acauliswas evaluated for its antibacterial and antibiofilm inhibitory activities against some known food-borne bacteria. The FTIR, FE-SEM, DLS and zeta-potential analysis were performed for confirming loading process, morphological appearance, hydrodynamic diameter and surface charge of the nanoparticles respectively. The results confirmed that, the nanoparticles had semi-spherical shape with the mean hydrodynamic diameter and surface charge of 89.8 ± 5.8 nm and 10.78 ± 2.7 mv respectively. Furthermore, the FTIR analysis approved that the nanoparticles were successfully loaded with ethyl acetate fraction fromP.acaulis. The antibacterial and biofilm inhibitory activities of the nanoformulated fraction were significantly increased against the tested Gram positive strains than free sample. The results also confirmed that the fraction release from the nanoparticles follows a sustained manner release after 30 h in a logarithmic pattern. Based on the obtained results, chitosan based nanoformulation ofP. acauliscan be considered for more evaluations to serve as an alternative natural antibiotic.}, } @article {pmid35704732, year = {2022}, author = {Yarkarami, F and Kazemian, H and Sadeghifard, N and Pakzad, R and Jalilian, FA and Asadollahi, P and Hematian, A and Pakzad, I}, title = {Inhibitory Effects of Carvacrol on Biofilm Formation and Expression of Biofilm Related Genes in Clinical Isolates of Enterococcus faecalis.}, journal = {Clinical laboratory}, volume = {68}, number = {6}, pages = {}, doi = {10.7754/Clin.Lab.2021.210853}, pmid = {35704732}, issn = {1433-6510}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/metabolism/pharmacology/therapeutic use ; Biofilms ; Cymenes ; Enterococcus faecalis/genetics ; *Gram-Positive Bacterial Infections/microbiology ; Humans ; Iran ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Nowadays, novel antimicrobial strategies are being developed which focus on debilitating, rather than killing the microorganisms. In this regard, anti-biofilm therapy is one of the important ways to combat bacterial infections. Therefore, the aim of the current study was to evaluate the anti-biofilm activity of Carvacrol against E. faecalis by means of its effects on biofilm formation as well as on the gene expression levels of the two biofilm related genes, Epa and Esp.

METHODS: A total of 40 clinical strains of E. faecalis were collected from three hospitals in Tehran, Iran during 2020. These isolates were confirmed by biochemical and genotypic methods. Antibacterial and anti-biofilm activity of Carvacrol essence were determined according the standard protocol. Finally, expression level of the biofilm related genes (Epa and Esp) were evaluated before and after the treatment with Carvacrol.

RESULTS: A total of 14 isolates were considered as strong biofilm producers and were used for analysis. Carvacrol essence showed the best antibacterial activity at 2,500 μg/mL concentration against all the isolates, the biofilm formation capacity was decreased by Carvacrol essence, and it was statistically significant (p < 0.05). Expression levels of the Esp gene were decreased in 5 isolates while increased in 3 isolates following the Carvacrol treatment. Ex-pression levels of the EpaI gene was significantly decreased (p < 0.05) in 4 isolates following the Carvacrol treatment.

CONCLUSIONS: In conclusion, the results presented in this study suggest that carvacrol extract exhibits significant antimicrobial and anti-biofilm properties against E. faecalis, even against vancomycin resistant isolates.}, } @article {pmid35704683, year = {2022}, author = {Feitosa-Junior, OR and Souza, APS and Zaini, PA and Baccari, C and Ionescu, M and Pierry, PM and Uceda-Campos, G and Labroussaa, F and Almeida, RPP and Lindow, SE and da Silva, AM}, title = {The XadA Trimeric Autotransporter Adhesins in Xylella fastidiosa Differentially Contribute to Cell Aggregation, Biofilm Formation, Insect Transmission and Virulence to Plants.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {35}, number = {9}, pages = {857-866}, doi = {10.1094/MPMI-05-22-0108-R}, pmid = {35704683}, issn = {0894-0282}, mesh = {Adhesins, Bacterial/genetics/metabolism ; Animals ; Biofilms ; Insecta ; Plant Diseases/microbiology ; Type V Secretion Systems/metabolism ; Virulence ; *Vitis/microbiology ; *Xylella ; }, abstract = {Surface adhesion strategies are widely employed by bacterial pathogens during establishment and systemic spread in their host. A variety of cell-surface appendages such as pili, fimbriae, and afimbrial adhesins are involved in these processes. The phytopathogen Xylella fastidiosa employs several of these structures for efficient colonization of its insect and plant hosts. Among the adhesins encoded in the X. fastidiosa genome, three afimbrial adhesins, XadA1, Hsf/XadA2, and XadA3, are predicted to be trimeric autotransporters with a C-terminal YadA-anchor membrane domain. We analyzed the individual contributions of XadA1, XadA2, and XadA3 to various cellular behaviors both in vitro and in vivo. Using isogenic X. fastidiosa mutants, we found that cell-cell aggregation and biofilm formation were severely impaired in the absence of XadA3. No significant reduction of cell-surface attachment was found with any mutant under flow conditions. Acquisition by insect vectors and transmission to grapevines were reduced in the XadA3 deletion mutant. While the XadA3 mutant was hypervirulent in grapevines, XadA1 or XadA2 deletion mutants conferred lower disease severity than the wild-type strain. This insight of the importance of these adhesive proteins and their individual contributions to different aspects of X. fastidiosa biology should guide new approaches to reduce pathogen transmission and disease development. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.}, } @article {pmid35704575, year = {2022}, author = {Worlitzer, VM and Jose, A and Grinberg, I and Bär, M and Heidenreich, S and Eldar, A and Ariel, G and Be'er, A}, title = {Biophysical aspects underlying the swarm to biofilm transition.}, journal = {Science advances}, volume = {8}, number = {24}, pages = {eabn8152}, pmid = {35704575}, issn = {2375-2548}, abstract = {Bacteria organize in a variety of collective states, from swarming-rapid surface exploration, to biofilms-highly dense immobile communities attributed to stress resistance. It has been suggested that biofilm and swarming are oppositely controlled, making this transition particularly interesting for understanding the ability of bacterial colonies to adapt to challenging environments. Here, the swarm to biofilm transition is studied in Bacillus subtilis by analyzing the bacterial dynamics both on the individual and collective scales. We show that both biological and physical processes facilitate the transition. A few individual cells that initiate the biofilm program cause nucleation of large, approximately scale-free, stationary aggregates of trapped swarm cells. Around aggregates, cells continue swarming almost unobstructed, while inside, trapped cells are added to the biofilm. While our experimental findings rule out previously suggested purely physical effects as a trigger for biofilm formation, they show how physical processes, such as clustering and jamming, accelerate biofilm formation.}, } @article {pmid35703501, year = {2022}, author = {Wu, C and Tang, J and Limlingan Malit, JJ and Wang, R and Sung, HH and Williams, ID and Qian, PY}, title = {Bathiapeptides: Polythiazole-Containing Peptides from a Marine Biofilm-Derived Bacillus sp.}, journal = {Journal of natural products}, volume = {85}, number = {7}, pages = {1751-1762}, doi = {10.1021/acs.jnatprod.2c00290}, pmid = {35703501}, issn = {1520-6025}, mesh = {*Bacillus/metabolism ; Biofilms ; *Biological Products/metabolism ; Humans ; Magnetic Resonance Spectroscopy ; Peptides/metabolism ; }, abstract = {Bacteria in marine biofilms are a rich reservoir of natural products. To facilitate novel secondary metabolite discovery, we investigated the metabolic profile of a marine biofilm-derived Bacillus sp. B19-2 by combining bioinformatics and LC-UV-MS analyses. After dereplication and purification of putatively unknown compounds, a new family of compounds 1-8 was uncovered and named bathiapeptides. Structural elucidation using NMR, HRESIMS, ozonolysis, advanced Marfey's analysis, and X-ray diffraction revealed that bathiapeptides are polypeptides that contain a rare polythiazole moiety. These compounds exhibited strong cytotoxicity against Hep G2, HeLa, MCF-7, and MGC-803 cell lines, and the lowest IC50 value was 0.5 μM. An iterative biosynthesis logic in bathiapeptides' biosynthesis was proposed based on the identified chemical structures and putative gene cluster analysis.}, } @article {pmid35703379, year = {2022}, author = {Li, Q and Liu, J and Xu, Y and Liu, H and Zhang, J and Wang, Y and Sun, Y and Zhao, M and Liao, L and Wang, X}, title = {Fast Cross-Linked Hydrogel as a Green Light-Activated Photocatalyst for Localized Biofilm Disruption and Brush-Free Tooth Whitening.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {25}, pages = {28427-28438}, doi = {10.1021/acsami.2c00887}, pmid = {35703379}, issn = {1944-8252}, mesh = {Biofilms ; Humans ; Hydrogels/pharmacology ; *Tooth ; *Tooth Bleaching ; *Tooth Discoloration/therapy ; }, abstract = {Biofilm-driven caries and tooth discoloration are two major problems in oral health care. The current methods have the disadvantages of insufficient biofilm targeting and irreversible enamel damage. Herein, an injectable sodium alginate hydrogel membrane doped with bismuth oxychloride (Bi12O17Cl2) and cubic cuprous oxide (Cu2O) nanoparticles was designed to simultaneously achieve local tooth whitening and biofilm removal through a photodynamic dental therapy process. This fast cross-linked hydrogel could form a biofilm removal coating on the target tooth surface precisely. Afterward, reactive oxygen species was effectively released on demand under green light, which could not only eradicate the biofilm but also whiten the tooth non-destructively in a facile manner without significant damage to both the enamel and biological cells. After the usage, the removal of this hydrogel can also enhance the effect of biofilm destruction and caries prevention.}, } @article {pmid35700910, year = {2022}, author = {Park, S and Lee, ES and Jung, HI and Kim, BI}, title = {Optical detection of oral biofilm in hospitalized geriatric patients using quantitative light-induced fluorescence technology.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {39}, number = {}, pages = {102962}, doi = {10.1016/j.pdpdt.2022.102962}, pmid = {35700910}, issn = {1873-1597}, mesh = {Aged ; Biofilms ; *Dental Caries ; Fluorescence ; Humans ; *Photochemotherapy/methods ; *Quantitative Light-Induced Fluorescence ; Technology ; }, abstract = {Detection and removal of pathological oral biofilm are essential in hospitalized geriatric patients as the biofilm can lead to lung infection. However, as elderly patients often have cognitive and physical impairments, general oral examination is complicated and detection of pathological biofilms is challenging. Quantitative light-induced fluorescence (QLF) technology, which is currently actively used to detect bacterial structures in the oral cavity, is used to detect dental biofilm and to identify various oral bacterial infections. We confirmed the applicability of QLF technology to oral hygiene assessment and evaluation of hospitalized geriatric patients using the QLF technology to detect and remove the pathological oral biofilm in a hospitalized geriatric patient. The oral biofilm attached to the oral mucosa was difficult to observe with the naked eye. However, it was detected with red fluorescence on QLF images, which helped us observe the to detect pathological oral biofilm and evaluate the effectiveness of oral hygiene care (OHC). After OHC, the strong red fluorescence expressed in the oral mucosa was no longer observed. This change in the clinical aspect of red fluorescence suggests that QLF can be used to detect pathological oral biofilm accumulated on the oral mucous membrane and evaluate the effectiveness of OHC in hospitalized patients with extremely poor oral hygiene.}, } @article {pmid35700566, year = {2022}, author = {Gujinović, L and Maravić, A and Kalinić, H and Dželalija, M and Šestanović, S and Zanchi, D and Šamanić, I}, title = {Metagenomic analysis of pioneer biofilm-forming marine bacteria with emphasis on Vibrio gigantis adhesion dynamics.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {217}, number = {}, pages = {112619}, doi = {10.1016/j.colsurfb.2022.112619}, pmid = {35700566}, issn = {1873-4367}, mesh = {Biofilms ; *Metagenomics ; RNA, Ribosomal, 16S/genetics ; *Vibrio/genetics ; }, abstract = {Marine biofilms occur frequently and spontaneously in seawater, on almost any submerged solid surface. At the early stages of colonization, it consists of bacteria and evolves into a more complex community. Using 16S rRNA amplicon sequencing and comparative metagenomics, the composition and predicted functional potential of one- to three-day old bacterial communities in surface biofilms were investigated and compared to that of seawater. This confirmed the autochthonous marine bacterium Vibrio gigantis as an early and very abundant biofilm colonizer, also functionally linked to the genes associated with cell motility, surface attachment, and communication via signaling molecules (quorum sensing), all crucial for biofilm formation. The dynamics of adhesion on a solid surface of V. gigantis alone was also monitored in controlled laboratory conditions, using a newly designed and easily implementable protocol. Resulting in a calculated percentage of bacteria-covered surface, a convincing tendency of spontaneous adhering was confirmed. From the multiple results, its quantified and reproducible adhesion dynamics will be used as a basis for future experiments involving surface modifications and coatings, with the goal of preventing adhesion.}, } @article {pmid35700313, year = {2022}, author = {Li, P and Yu, M and Ke, X and Gong, X and Li, Z and Xing, X}, title = {Cytocompatible Amphipathic Carbon Quantum Dots as Potent Membrane-Active Antibacterial Agents with Low Drug Resistance and Effective Inhibition of Biofilm Formation.}, journal = {ACS applied bio materials}, volume = {5}, number = {7}, pages = {3290-3299}, doi = {10.1021/acsabm.2c00292}, pmid = {35700313}, issn = {2576-6422}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Carbon/pharmacology ; Drug Resistance ; Humans ; *Quantum Dots/toxicity ; *Staphylococcal Infections ; }, abstract = {It is very challenging to design nanomaterials with both excellent antibacterial activity and cytocompatibility when facing bacterial infection. Here, inspired by antimicrobial peptides (AMPs), we fabricate carbon quantum dots (CQDs) derived from hydrophobic tryptophan and hydrophilic lysine or arginine (Lys/Trp-CQDs and Arg/Trp-CQDs), which possess amphipathic properties. These CQDs could effectively destroy bacterial membranes without developing resistance, inhibit biofilms formed by Staphylococcus aureus, and exhibit good in vitro biocompatibility. The antibacterial activities are caused by not only surface cationic structures and excess intracellular reactive oxygen species (ROS) generated by the CQDs but also the effects of the surface hydrophobic groups. These combined mechanisms of actions lead to bacterial membrane disruption, which raises the hope for combating bacterial infection without concern about drug resistance. What's more, the effect of amphiphilicity on balancing sterilization with biocompatibility expands the research ideas for developing available antibacterial nanomaterials.}, } @article {pmid35700135, year = {2022}, author = {Deng, Z and Hou, K and Valencak, TG and Luo, XM and Liu, J and Wang, H}, title = {AI-2/LuxS Quorum Sensing System Promotes Biofilm Formation of Lactobacillus rhamnosus GG and Enhances the Resistance to Enterotoxigenic Escherichia coli in Germ-Free Zebrafish.}, journal = {Microbiology spectrum}, volume = {10}, number = {4}, pages = {e0061022}, pmid = {35700135}, issn = {2165-0497}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Carbon-Sulfur Lyases/genetics/metabolism ; *Enterotoxigenic Escherichia coli/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Inflammation ; *Lacticaseibacillus rhamnosus/metabolism ; Quorum Sensing ; Zebrafish/metabolism ; }, abstract = {The LuxS enzyme plays a key role in both quorum sensing (QS) and the regulation of bacterial growth. It catalyzes the production of autoinducer-2 (AI-2) signaling molecule, which is a component of the methyl cycle and methionine metabolism. This study aimed at investigating the differences between the Lactobacillus rhamnosus GG (LGG) wild-type strain (WT) and its luxS mutant (ΔluxS) during biofilm formation and when resisting to inflammation caused by Enterotoxigenic Escherichia coli (ETEC) in germ-free zebrafish. Our results suggest that in the absence of luxS when LGG was knocked out, biofilm formation, extracellular polysaccharide secretion and adhesion were all compromised. Addition of synthetic AI-2 indeed rescued, at least partially, the deficiencies observed in the mutant strain. The colonizing and immunomodulatory function in WT versus ΔluxS mutants were further studied in a germ-free zebrafish model. The concentration of AI-2 signaling molecules decreased sharply in zebrafish infected with the ΔluxS. At the same time, compared with the ΔluxS, the wild-type strain could colonize the germ-free zebrafish more effectively. Our transcriptome results suggest that genes involved in immunity, signal transduction, and cell adhesion were downregulated in zebrafish infected with ΔluxS and WT. In the WT, the immune system of germ-free zebrafish was activated more effectively through the MAPK and NF-κB pathway, and its ability to fight the infection against ETEC was increased. Together, our results demonstrate that the AI-2/LuxS system plays an important role in biofilm formation to improve LGG and alleviate inflammation caused by ETEC in germ-free zebrafish. IMPORTANCE Lactobacillus rhamnosus GG is a widely used probiotic to improve host intestinal health, promote growth, reduce diarrhea, and modulate immunity. In recent years, the bacterial quorum sensing system has attracted much attention; however, there has not been much research on the effect of the LuxS/AI-2 quorum sensing system of Lactobacillus on bacteriostasis, microbial ecology balance, and immune regulation in intestine. In this study, we used germ-free zebrafish as an animal model to compare the differences between wild-type and luxS mutant strains. We showed how AI-2/LuxS QS affects the release of AI-2 and how QS regulates the colonization, EPS synthesis and biofilm formation of LGG. This study provides an idea for the targeted regulation of animal intestinal health with probiotics by controlling bacteria quorum sensing system.}, } @article {pmid35699894, year = {2022}, author = {Lauková, A and Chrastinová, Ľ and Micenková, L and Bino, E and Kubašová, I and Kandričáková, A and Gancarčíková, S and Plachá, I and Holodová, M and Grešáková, Ľ and Formelová, Z and Simonová, MP}, title = {Enterocin M in Interaction in Broiler Rabbits with Autochthonous, Biofilm-Forming Enterococcus hirae Kr8 Strain.}, journal = {Probiotics and antimicrobial proteins}, volume = {14}, number = {5}, pages = {845-853}, pmid = {35699894}, issn = {1867-1314}, mesh = {Animals ; *Bacteriocins ; Biofilms ; *Enterococcus hirae ; Female ; Male ; Prospective Studies ; *Rabbits ; }, abstract = {Young rabbits are susceptible to gastrointestinal diseases caused by bacteria. Enterococcus hirae can be associated with diseases. But enterocins produced by some enterococcal species can prevent/reduce this problem. Therefore, the interaction of enterocin M with a biofilm-forming, autochthonous E. hirae Kr8[+] strain was tested in rabbits to assess enterocin potential in vivo. Rabbits (96), aged 35 days, both sexes, meat line M91 breed were divided into four groups, control C and three experimental groups. The rabbits in C received the standard diet, rabbits in experimental group 1 (E1) received 10[8] CFU/mL of Kr8[+], a dose 500 µL/animal/day, E2 received Ent M (50 µL/animal/day), and E3 received both Kr8[+] and Ent M in their drinking water over 21 days. The experiment lasted 42 days. Feces and blood were sampled at day 0/1 (at the start of the experiment, fecal mixture of 96 animals, n = 10), at day 21 (five fecal mixtures per group, n = 5), and at day 42 (21 days after additives cessation, the same). At days 21 and 42, four rabbits from each group were slaughtered, and cecum and appendix were sampled for standard microbial analysis. Ent M showed decreased tendency of Kr8[+]. Using next-generation sequencing, the phyla detected with the highest abundance were Firmicutes, Verrucomicrobia, Bacteroidetes, Tenericutes, Proteobacteria, Cyanobacteria, Saccharibacteria, and Actinobacteria. Interaction of Ent M with some phyla resulted in reduced abundance percentage. At day 21, significantly increased phagocytic activity (PA) was found in E1 and E2 (p < 0.001). Kr8[+] did not attack PA and did not stimulate oxidative stress. But Ent M supported PA. The prospective importance of this study lies in beneficial interaction of enterocin in host body.}, } @article {pmid35699787, year = {2022}, author = {Xu, JG and Hu, HX and Chen, JY and Xue, YS and Kodirkhonov, B and Han, BZ}, title = {Comparative study on inhibitory effects of ferulic acid and p-coumaric acid on Salmonella Enteritidis biofilm formation.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {8}, pages = {136}, pmid = {35699787}, issn = {1573-0972}, support = {2017YFC1600806//Key Technologies Research and Development Program/ ; 2020TC116//Chinese Universities Scientific Fund/ ; }, mesh = {Biofilms ; *Coumaric Acids/pharmacology ; *Salmonella enteritidis ; }, abstract = {Biofilm cells exhibit higher resistance than their planktonic counterparts to commonly used disinfectants in food industry. Phenolic acids are promising substitute offering less selective pressure than traditional antibiotics. This study aims to evaluate the inhibitory effects of ferulic acid (FA) and p-coumaric acid (p-CA) on Salmonella Enteritidis biofilm formation and explore the underlying inhibitory mechanisms. The minimal inhibitory concentration (MIC) of FA and p-CA were 1.0 and 0.5 mg/ml, respectively. The sub-inhibitory concentration (1/8 MIC) significantly decreased biofilm formation without growth inhibitory effects. The biomass and extracellular polymeric substances (EPS) of S. Enteritidis biofilm as well as the bacterial swimming and chemotaxis abilities were significantly decreased when exposed to sub-MIC concentrations of FA and p-CA. These two phenolic acids showed high affinity to proteins involved in flagella motility and repressed the S. Enteritidis biofilm formation-related gene expressions. Furthermore, these two phenolic acids maintained high antibiofilm efficiency in simulated food processing conditions. This study provided valuable information of multiple phenotypic and molecular responses of S. Enteritidis to these two phenolic acids.}, } @article {pmid35699414, year = {2022}, author = {Ravel, G and Bergmann, M and Trubuil, A and Deschamps, J and Briandet, R and Labarthe, S}, title = {Inferring characteristics of bacterial swimming in biofilm matrix from time-lapse confocal laser scanning microscopy.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {35699414}, issn = {2050-084X}, mesh = {Bacteria ; Biofilms ; Ecosystem ; *Extracellular Polymeric Substance Matrix ; Microscopy, Confocal ; *Swimming ; Time-Lapse Imaging ; }, abstract = {Biofilms are spatially organized communities of microorganisms embedded in a self-produced organic matrix, conferring to the population emerging properties such as an increased tolerance to the action of antimicrobials. It was shown that some bacilli were able to swim in the exogenous matrix of pathogenic biofilms and to counterbalance these properties. Swimming bacteria can deliver antimicrobial agents in situ, or potentiate the activity of antimicrobial by creating a transient vascularization network in the matrix. Hence, characterizing swimmer trajectories in the biofilm matrix is of particular interest to understand and optimize this new biocontrol strategy in particular, but also more generally to decipher ecological drivers of population spatial structure in natural biofilms ecosystems. In this study, a new methodology is developed to analyze time-lapse confocal laser scanning images to describe and compare the swimming trajectories of bacilli swimmers populations and their adaptations to the biofilm structure. The method is based on the inference of a kinetic model of swimmer populations including mechanistic interactions with the host biofilm. After validation on synthetic data, the methodology is implemented on images of three different species of motile bacillus species swimming in a Staphylococcus aureus biofilm. The fitted model allows to stratify the swimmer populations by their swimming behavior and provides insights into the mechanisms deployed by the micro-swimmers to adapt their swimming traits to the biofilm matrix.}, } @article {pmid35698852, year = {2022}, author = {Protasiuk, LE and Serov, NS and Lokteva, AV and Kladko, DV and Koshel, EI and Vinogradov, VV}, title = {Mechano-bactericidal anisotropic particles for oral biofilm treatment.}, journal = {Journal of materials chemistry. B}, volume = {10}, number = {25}, pages = {4867-4877}, doi = {10.1039/d2tb00582d}, pmid = {35698852}, issn = {2050-7518}, mesh = {Anisotropy ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; Quality of Life ; *Stomatognathic Diseases/drug therapy ; *Toothpastes/pharmacology/therapeutic use ; }, abstract = {Bacterial biofilms play a major etiological role in dental diseases worldwide. Currently, toothpastes with bactericidal chemicals and abrasive materials are used as preventive care methods. However, chemicals can cause adverse side effects, with the use of antibiotics, fluorides, and antiseptics drastically reducing quality of life. At the same time, the rational design of bulk toothpaste materials has remained unexplored. In this work, we demonstrated a mechano-bactericidal strategy as an antibiotic-free and tooth-safe approach for dental biofilm elimination based on shape-anisotropy CaCO3 (cubic-, stick-, and urchin-shaped). As proof-of-concept, we demonstrated superior efficiency during biofilm eradication from ex vivo teeth using urchin- and stick-shaped microparticles involving both Escherichia coli K12 (227 ± 32.6% and 215 ± 33%, respectively) and Staphylococcus aureus ATCC 209P (210 ± 54.7% and 202 ± 55.5%, respectively) compared to the spherical particles that are employed in conventional toothpastes. These findings will potentially give rise to the development of novel and safer toothpastes with antibiotic-free bactericidal activity for the prevention of dental diseases.}, } @article {pmid35698329, year = {2022}, author = {Vandana, and Das, S}, title = {Genetic regulation, biosynthesis and applications of extracellular polysaccharides of the biofilm matrix of bacteria.}, journal = {Carbohydrate polymers}, volume = {291}, number = {}, pages = {119536}, doi = {10.1016/j.carbpol.2022.119536}, pmid = {35698329}, issn = {1879-1344}, mesh = {Bacteria/genetics/metabolism ; Bacterial Proteins/metabolism ; *Biofilms ; Cyclic GMP/metabolism ; *Extracellular Polymeric Substance Matrix ; Gene Expression Regulation, Bacterial ; Polysaccharides ; }, abstract = {Bacterial biofilm formation is dependent mainly on the decision-making process of the two key factors of the gene regulatory network, namely the Quorum Sensing (QS) system and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). c-di-GMP is a secondary messenger molecule that enhances extracellular polysaccharides production by activating pelD and alg44. Genes involved in the metabolic pathway for the biosynthesis of extracellular polysaccharides are clustered within the genome of the producing bacteria. The extracellular polysaccharide gene cluster encodes specific regulatory enzymes and transporter proteins involved in the different steps of the biosynthesis route. The diversity of extracellular polysaccharides produced by the bacteria is synthesized via different biosynthesis pathways. Understanding the genetic regulation and biosynthesis of extracellular polysaccharides is crucial for tailor-made polymers via genetic, metabolic, and protein engineering approaches. This review illustrates structure, structure-function relationship, genetics, regulation, biosynthetic pathways, and various applications of extracellular polysaccharides.}, } @article {pmid35696784, year = {2022}, author = {Deng, YH and Ricciardulli, T and Won, J and Wade, MA and Rogers, SA and Boppart, SA and Flaherty, DW and Kong, H}, title = {Self-locomotive, antimicrobial microrobot (SLAM) swarm for enhanced biofilm elimination.}, journal = {Biomaterials}, volume = {287}, number = {}, pages = {121610}, pmid = {35696784}, issn = {1878-5905}, support = {R01 AI160671/AI/NIAID NIH HHS/United States ; R01 EB013723/EB/NIBIB NIH HHS/United States ; R01 EB028615/EB/NIBIB NIH HHS/United States ; }, abstract = {Biofilm is a major cause of infections and infrastructure deterioration, largely due to molecular diffusion restrictions that hamper the antimicrobial activity of traditional antibiotics and disinfectants. Here, we present a self-locomotive, antimicrobial microrobot (SLAM) swarm that can penetrate, fracture, and detach biofilm and, in turn, nullify bacterial resistance to antibiotics. The SLAM is assembled by loading a controlled mass of manganese oxide nanosheets on diatoms with the polydopamine binder. In hydrogen peroxide solution, SLAMs produce oxygen bubbles that generate thrust to penetrate the rigid and dense Pseudomonas aeruginosa biofilm and self-assemble into a swarm that repeatedly surrounds, expands, and bursts oxygen bubbles. The resulting cavities continue to deform and fracture extracellular polymeric substances from microgrooved silicone substrates and wounded skin explants while decreasing the number of viable bacterial cells. Additionally, SLAM allows irrigating water or antibiotics to access the residual biofilm better, thus enhancing the synergistic efficacy in killing up to 99.9% of bacterial cells.}, } @article {pmid35695502, year = {2022}, author = {Chapartegui-González, I and Khakhum, N and Stockton, JL and Torres, AG}, title = {Evaluating the Contribution of the Predicted Toxin-Antitoxin System HigBA to Persistence, Biofilm Formation, and Virulence in Burkholderia pseudomallei.}, journal = {Infection and immunity}, volume = {90}, number = {7}, pages = {e0003522}, pmid = {35695502}, issn = {1098-5522}, mesh = {Anti-Bacterial Agents/pharmacology ; *Antitoxins/genetics ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Burkholderia pseudomallei/genetics/metabolism ; Humans ; Levofloxacin ; *Toxin-Antitoxin Systems/genetics ; Virulence/genetics ; }, abstract = {Melioidosis is an underreported human disease caused by the Gram-negative intracellular pathogen Burkholderia pseudomallei (Bpm). Both the treatment and the clearance of the pathogen are challenging, with high relapse rates leading to latent infections. This has been linked to the bacterial persistence phenomenon, a growth arrest strategy that allows bacteria to survive under stressful conditions, as in the case of antibiotic treatment, within a susceptible clonal population. At a molecular level, this phenomenon has been associated with the presence of toxin-antitoxin (TA) systems. We annotated the Bpm K96243 genome and selected 11 pairs of genes encoding for these TA systems, and their expression was evaluated under different conditions (supralethal antibiotic conditions; intracellular survival bacteria). The predicted HigB toxin (BPSL3343) and its predicted antitoxin HigA (BPS_RS18025) were further studied using mutant construction. The phenotypes of two mutants (ΔhigB and ΔhigB ΔhigA) were evaluated under different conditions compared to the wild-type (WT) strain. The ΔhigB toxin mutant showed a defect in intracellular survival on macrophages, a phenotype that was eliminated after levofloxacin treatment. We found that the absence of the toxin provides an advantage over the WT strain, in both in vitro and in vivo models, during persister conditions induced by levofloxacin. The lack of the antitoxin also resulted in differential responses to the conditions evaluated, and under some conditions, it restored the WT phenotype, overall suggesting that both toxin and antitoxin components play a role in the persister-induced phenotype in Bpm.}, } @article {pmid35695458, year = {2022}, author = {Hjort, K and Fermér, E and Tang, PC and Andersson, DI}, title = {Antibiotic Minimal Selective Concentrations and Fitness Costs during Biofilm and Planktonic Growth.}, journal = {mBio}, volume = {13}, number = {3}, pages = {e0144722}, pmid = {35695458}, issn = {2150-7511}, mesh = {*Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Escherichia coli/physiology ; *Escherichia coli Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; Plankton/genetics ; }, abstract = {The use and misuse of antibiotics have resulted in the selection of difficult-to-treat resistant bacteria. Two key parameters that influence the selection of resistant bacteria are the minimal selective concentration (MSC) and the fitness cost of resistance, both of which have been measured during planktonic growth in several studies. However, bacterial growth most often occurs in biofilms, and it is unclear if and how these parameters differ under these two growth conditions. To address this knowledge gap, we compared a selection of several types of antibiotic-resistant Escherichia coli mutants during planktonic and biofilm growth to determine the fitness costs and MSCs. Biofilm-forming Escherichia coli strains are commonly found in catheter-associated and recurrent urinary tract infections. Isogenic strains of a biofilm-forming E. coli strain, differing only in the resistance mechanisms and the fluorescent markers, were constructed, and susceptible and resistant bacteria were grown in head-to-head competitions at various concentrations of antibiotics under planktonic and biofilm conditions. Mutants with resistance to five different antibiotics were studied. The results show that during both planktonic and biofilm growth, selection for the resistant mutants occurred for all antibiotics at sub-MICs far below the MIC of the antibiotic. Even though differences were seen, the MSC values and the fitness costs did not differ systematically between planktonic and biofilm growth, implying that despite the different growth modes, the basic selection parameters are similar. These findings highlight the risk that resistant mutants may, similarly to planktonic growth, also be selected at sub-MICs of antibiotics in biofilms. IMPORTANCE Our understanding of how and where antibiotic resistance is selected in response to antibiotic exposure is still limited, and this is particularly true for selective processes when bacteria are growing in biofilms, arguably the most significant mode of growth of bacteria in human and animal infections as well as in other settings. In this study, we compared how different types of resistant E. coli strains were selected in response to antibiotic exposure during planktonic and biofilm growth. Determination of the minimal selective concentrations (MSCs) and fitness costs of resistance showed that they were comparable under these two different conditions, even though some differences were observed. Importantly, the MSCs were far below the MICs for all mutants under both planktonic and biofilm growth, emphasizing the significance of low antibiotic concentrations in driving the emergence and enrichment of resistant bacteria.}, } @article {pmid35695457, year = {2022}, author = {Dodson, TA and Carlson, EA and Wamer, NC and Morse, CN and Gadient, JN and Prestwich, EG}, title = {Characterization of Distinct Biofilm Cell Subpopulations and Implications in Quorum Sensing and Antibiotic Resistance.}, journal = {mBio}, volume = {13}, number = {3}, pages = {e0019122}, pmid = {35695457}, issn = {2150-7511}, support = {R01 AI148570/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; *Bacterial Proteins/metabolism ; Biofilms ; Drug Resistance, Microbial ; Humans ; Pseudomonas aeruginosa/metabolism ; *Quorum Sensing/genetics ; }, abstract = {Bacteria change phenotypically in response to their environment. Free swimming cells transition to biofilm communities that promote cellular cooperativity and resistance to stressors and antibiotics. We uncovered three subpopulations of cells with diverse phenotypes from a single-species Pseudomonas aeruginosa PA14 biofilm, and used a series of steps to isolate, characterize, and map these cell subpopulations in a biofilm. The subpopulations were distinguishable by size and morphology using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Additionally, growth and dispersal of biofilms originating from each cell subpopulation exhibited contrasting responses to antibiotic challenge. Cell subpopulation surface charges were distinctly different, which led us to examine the ionizable surface molecules associated with each subpopulation using mass spectrometry. Matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of cell subpopulations revealed ions unique to each subpopulation of cells that significantly co-localized with ions associated with quorum sensing. Transcript levels of algR, lasR, and rhlI in subpopulations isolated from biofilms differed from levels in planktonic stationary and mid-log cell subpopulations. These studies provide insight into diverse phenotypes, morphologies, and biochemistries of PA14 cell subpopulations for potential applications in combating bacterial pathogenesis, with medical, industrial, and environmental complications. IMPORTANCE Pseudomonas aeruginosa biofilms can cause chronic infections in burn wounds, grow on medical equipment, and proliferate in the lungs of people with cystic fibrosis. These inherently antibiotic tolerant biofilms are difficult to eradicate largely due to the complexity of the biofilm environment. Developing more effective biofilm treatments is reliant upon understanding biofilm heterogeneity. We identified and characterized three separate cell subpopulations found in P. aeruginosa PA14 biofilms. The distinct morphologies, phenotypes, and biochemistries of each of these cell subpopulations indicate that they contribute differently to the overall biofilm environment. These findings demonstrate that bacterial cells of the same species exhibit diversity that implies distinct roles in biofilm initiation, maturation, and maintenance.}, } @article {pmid35693228, year = {2022}, author = {Peerzada, Z and Kanhed, AM and Desai, KB}, title = {Effects of active compounds from Cassia fistula on quorum sensing mediated virulence and biofilm formation in Pseudomonas aeruginosa.}, journal = {RSC advances}, volume = {12}, number = {24}, pages = {15196-15214}, pmid = {35693228}, issn = {2046-2069}, abstract = {Pseudomonas aeruginosa infections are attributed to its ability to form biofilms and are difficult to eliminate with antibiotic treatment. Biofilm formation is regulated by quorum sensing (QS), an intracellular bacterial communication mechanism that allows the activation of numerous virulence factors and secondary metabolites. Targeting the QS pathway is a potential approach that prevents QS-controlled phenotypes and biofilm formation. For the first time, the current work has identified antiquorum sensing activity in the partially purified four fractions from the hot ethyl acetate extract of Cassia fistula fruit pods. Of the four fractions, only fraction-1 gave decreased AHL activity; the phytoconstituents in this fraction were identified as rhein, 3-aminodibenzofuran, 5-(hydroxymethyl)-2-(dimethoxymethyl)furan, and dihydrorhodamine. Fraction-1 (1 mg ml[-1]) and rhein (0.15 mg ml[-1]) showed 63% and 42.7% reduction in short-chain AHL production, respectively, without hindering the bacterial growth. Fraction-1 inhibited QS-mediated extracellular virulence factors viz. protease, elastase, pyocyanin, and rhamnolipid (p < 0.05). Quantitative analysis of biofilm formation showed 77% & 62.4% reduction by fraction-1 (1 mg ml[-1]) and rhein (0.15 mg ml[-1]) respectively. Confocal laser microscopy (CLMS) & scanning electron microscopy (SEM) confirmed the reduction of biofilm formation in Pseudomonas aeruginosa upon treatment with fraction-1 and rhein. Moreover, the in vivo study displayed that fraction-1 and rhein (standard) significantly enhanced the survival of Caenorhabditis elegans by suppressing the potency of virulence factors of Pseudomonas aeruginosa. Quantitative real-time polymerase chain reaction results demonstrated the down-regulation of QS-related genes, lasI, lasR, rhlI, and rhlR. In addition, in silico analysis divulged that a component identified by GC-MS displayed a strong affinity towards LasI and LasR. These findings suggest that potent phytochemicals from fraction-1, including rhein, could serve as novel phytotherapeutics in controlling emerging infections of antibiotic-resistant bacterial pathogens like Pseudomonas aeruginosa.}, } @article {pmid35691511, year = {2022}, author = {Hennequin, C and Forestier, C and Traore, O and Debroas, D and Bricheux, G}, title = {Plasmidome analysis of a hospital effluent biofilm: Status of antibiotic resistance.}, journal = {Plasmid}, volume = {122}, number = {}, pages = {102638}, doi = {10.1016/j.plasmid.2022.102638}, pmid = {35691511}, issn = {1095-9890}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Drug Resistance, Microbial ; Hospitals ; Plasmids/genetics ; }, abstract = {Plasmids are widely involved in the dissemination of characteristics within bacterial communities. Their genomic content can be assessed by high-throughput sequencing of the whole plasmid fraction of an environment, the plasmidome. In this study, we analyzed the plasmidome of a biofilm formed in the effluents of the teaching hospital of Clermont-Ferrand (France). Our analysis discovered >350 new complete plasmids, with a length ranging from 1219 to 40,193 bp. Forty-two plasmid incompatibility (Inc) groups were found among all the plasmid contigs. Ten large plasmids, described here in detail, were reconstructed from plasmid contigs, seven of which carried antibiotic resistance genes. Four plasmids potentially confer resistance to numerous families of antibiotics, including carbapenems, aminoglycosides, colistin, and chloramphenicol. Most of these plasmids were affiliated to Proteobacteria, a phylum of Gram-negative bacteria. This study therefore illustrates the composition of an environmental mixed biofilm in terms of plasmids and antibiotic resistance genes.}, } @article {pmid35690659, year = {2022}, author = {Tran, VN and Khan, F and Han, W and Luluil, M and Truong, VG and Yun, HG and Choi, S and Kim, YM and Shin, JH and Kang, HW}, title = {Real-time monitoring of mono- and dual-species biofilm formation and eradication using microfluidic platform.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {9678}, pmid = {35690659}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Candida albicans ; Humans ; *Microfluidics ; *Staphylococcus aureus ; }, abstract = {In a human host, bacterial Staphylococcus aureus and fungal Candida albicans pathogens form a mixed biofilm that causes severe mortality and morbidity. However, research on the formation and eradication of mixed biofilms under dynamic conditions is lacking. Thus, this study employed a microfluidic technique to analyze the real-time formation of mono- and dual-species (S. aureus and C. albicans) biofilms and noninvasive optical treatment of the established mature biofilm using 405-nm laser light. A herringbone mixer thoroughly mixed both bacterial and fungal cells in the growth media before being injected into the observation channels on the microfluidic chip. At a flow rate of 1.0 µL/min of growth media for 24 h, the bacterial biofilm coverage was up to 15% higher than that of the fungal biofilm (50% for bacteria vs. 35% for fungus). On the other hand, the dual-species biofilm yielded the highest coverage of ~ 96.5% because of the collective interaction between S. aureus and C. albicans. The number of cell proliferation events in S. aureus was higher than that of C. albicans for 12 h, which indicates that the S. aureus biofilm was developed faster than C. albicans. The novel in situ test platform showed a significant bactericidal effect (80%) of the 405-nm laser light at 1080 J/cm[2] towards the established S. aureus biofilm, whereas the same treatment removed approximately 69% of the mixed cells in the dual-species biofilm. This study revealed that the developed microfluidic platform could be utilized to monitor the formation of dual-species biofilms in real-time and laser-induced antimicrobial effects on dual-species biofilms.}, } @article {pmid35690445, year = {2022}, author = {Lee, S and Chen, J}, title = {Identification of the genetic elements involved in biofilm formation by Salmonella enterica serovar Tennessee using mini-Tn10 mutagenesis and DNA sequencing.}, journal = {Food microbiology}, volume = {106}, number = {}, pages = {104043}, doi = {10.1016/j.fm.2022.104043}, pmid = {35690445}, issn = {1095-9998}, mesh = {Biofilms ; Mutagenesis ; *Salmonella enterica/genetics ; Sequence Analysis, DNA ; Serogroup ; Tennessee ; }, abstract = {Biofilms are known to contribute to bacterial tolerance to desiccation and survival in low moisture foods. However, the molecular mechanisms underlying biofilm formation have not been fully elucidated. This study identified some of the genes that are implicated in biofilm formation by Salmonella enterica serovar Tennessee, the "peanut butter outbreak" strain. Mini-Tn10 mutagenesis was used in the study to generate random transposon insertion libraries. The ability of selected mutants in forming biofilms was compared with their wildtype parent using the crystal violet binding assay. Mutants forming significantly less (P ≤ 0.05) biofilm compared to their wildtype parent were selected for whole-genome sequencing. Mini-Tn10 insertion sites on mutant genomes were identified by comparing the acquired sequencing data with those in the Genbank using the BLAST search. In total, 56 mutants were obtained, and five were selected for further analysis according to the result of the biofilm assay. Sequencing analysis revealed that the mini-Tn10 interrupted the S. enterica genes that encode bacterial cell membrane lipoprotein, DNA topoisomerase III, attachment and invasion locus protein, bacteriocin immunity protein, and cell division protein. The information generated from the research should be useful in the control fo S. enterica in low-moisture foods and their production environments.}, } @article {pmid35690237, year = {2022}, author = {Raj Deena, S and Kumar, G and Vickram, AS and Rani Singhania, R and Dong, CD and Rohini, K and Anbarasu, K and Thanigaivel, S and Ponnusamy, VK}, title = {Efficiency of various biofilm carriers and microbial interactions with substrate in moving bed-biofilm reactor for environmental wastewater treatment.}, journal = {Bioresource technology}, volume = {359}, number = {}, pages = {127421}, doi = {10.1016/j.biortech.2022.127421}, pmid = {35690237}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Bioreactors ; Microbial Interactions ; Waste Disposal, Fluid ; Wastewater/analysis ; *Water Purification ; }, abstract = {In a moving bed-biofilm reactor (MBBR), the fluidization efficiency, immobilization of microbial cells, and treatment efficiency are directly influenced by the shape and pores of biofilm carriers. Moreover, the efficacy of bioremediation mainly depends on their interaction interface with microbes and substrate. This review aims to comprehend the role of different carrier properties such as material shapes, pores, and surface area on bioremediation productivity. A porous biofilm carrier with surface ridges containing spherical pores sizes > 1 mm can be ideal for maximum efficacy. It provides diverse environments for cell cultures, develops uneven biofilms, and retains various cell sizes and biomass. Moreover, the thickness of biofilm and controlled scaling shows a significant impact on MBBR performance. Therefore, the effect of these parameters in MBBR is discussed detailed in this review, through which existing literature and technical strategies that focus on the surface area as the primary factor can be critically assessed.}, } @article {pmid35689970, year = {2022}, author = {Cabo, ML and Rodríguez, A and Herrera, JR}, title = {Exploring communication signals inside the microbial community of a Listeria monocytogenes-carrying biofilm contamination site.}, journal = {International journal of food microbiology}, volume = {376}, number = {}, pages = {109773}, doi = {10.1016/j.ijfoodmicro.2022.109773}, pmid = {35689970}, issn = {1879-3460}, mesh = {Biofilms ; Lactones ; *Listeria monocytogenes ; *Microbiota ; Quorum Sensing ; }, abstract = {In nature, bacterial pathogens like L. monocytogenes, live in nature associated with other microbial species in spatially-structured communities called biofilms. In the food industry, biofilms contribute to the survival and persistence of L. monocytogenes within processing facilities, thereby enhancing its risk of cross-contaminating food products. The challenge of combating biofilms has triggered the search for new antibiofilm strategies including devising ways to interfere with cell communication mechanisms (quorum-sensing) that are known to be involved with biofilm development regulation. The aim of this study was to explore cell communication signals in a L. monocytogenes-carrying microbial community isolated from a meat processing plant (location No. 96) in order to elucidate the ecological interactions that could serve as a starting point for the development of new antibiofilm strategies. Quorum quenching (QQ) and quorum sensing (QS) activities were screened among 31 bacterial strains isolated from location No. 96. Whereas no QQ activity was detected against short-chain lactone N-hexanoyl-DL-homoserine lactone (C6-HSL), it was detected against N-dodecanoyl-DL-homoserine lactone (C12-HSL) in 7 isolates (23%), particularly in Pseudomonas monteilli, Rhodococcus sp. and Rhodococcus erythropolis. QS activity assays detected HC4, C4, C6, OC6, HC10 and C16 in all the extracts, being C4, C6 and OC6 with predominantly produced by Pseudomonas monteilli, Pseudomonas gesardii, Psychrobacter maritimus and Paracoccus sp. High production levels of C16-HSL by Paracoccus sp. and the role of this long-chain lactone as a self-inhibitor of cell aggregation led us to carry out further studies focused on the effects of a Paracoccus lactone extract (PLE) against the biofilm formation by L. monocytogenes. A quantitative microscopic analysis demonstrated a significant decrease (p < 0.05) in the area occupied by biofilms formed on stainless steel (SS) coupons by different strains of L. monocytogenes in the presence of PLEs. Conversely, no significant differences were observed in the total number of viable adhered cells on SS coupons with or without PLE. The observed effect was partially reproduced by the addition of pure C16-HSL to 24 h-biofilms of L. monocytogenes L1.96. These results demonstrate that the observed effects can be attributed, at least partially, to the HSLs contained in the PLE. Overall, the present results highlight how interspecies communication within a biofilm can open up new insights for the development of new ways to combat biofilm.}, } @article {pmid35689422, year = {2022}, author = {Ribeiro, M and Gomes, IB and Saavedra, MJ and Simões, M}, title = {Photodynamic therapy and combinatory treatments for the control of biofilm-associated infections.}, journal = {Letters in applied microbiology}, volume = {75}, number = {3}, pages = {548-564}, doi = {10.1111/lam.13762}, pmid = {35689422}, issn = {1472-765X}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-03021//Fundação para a Ciência e a Tecnologia/ ; //FEDER/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology/therapeutic use ; Bacteria ; Biofilms ; Penicillins/pharmacology ; *Photochemotherapy ; Photosensitizing Agents/pharmacology/therapeutic use ; Reactive Oxygen Species ; }, abstract = {The advent of antimicrobial resistance has added considerable impact to infectious diseases both in the number of infections and healthcare costs. Furthermore, the relentless emergence of multidrug-resistant bacteria, particularly in the biofilm state, has made mandatory the discovery of new alternative antimicrobial therapies that are capable to eradicate resistant bacteria and impair the development of new forms of resistance. Amongst the therapeutic strategies for treating biofilms, antimicrobial photodynamic therapy (aPDT) has shown great potential in inactivating several clinically relevant micro-organisms, including antibiotic-resistant 'priority bacteria' declared by the WHO as critical pathogens. Its antimicrobial effect is centred on the basis that harmless low-intensity light stimulates a non-toxic dye named photosensitizer, triggering the production of reactive oxygen species upon photostimulation. In addition, combination therapies of aPDT with other antimicrobial agents (e.g. antibiotics) have also drawn considerable attention, as it is a multi-target strategy. Therefore, the present review highlights the recent advances of aPDT against biofilms, also covering progress on combination therapy.}, } @article {pmid35688976, year = {2022}, author = {Suganya, M and Preethi, PS and Narenkumar, J and Prakash, AA and Devanesan, S and AlSalhi, MS and Rajasekar, A and Nanthini, AUR}, title = {Synthesis of silver nanoparticles from Indian red yeast rice and its inhibition of biofilm in copper metal in cooling water environment.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {51}, pages = {77800-77808}, pmid = {35688976}, issn = {1614-7499}, mesh = {Silver/pharmacology ; Copper/pharmacology ; *Metal Nanoparticles ; *Caustics/pharmacology ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Plant Extracts/pharmacology ; Water ; Microbial Sensitivity Tests ; }, abstract = {The development of environmentally acceptable benign techniques using purely natural methods is a cost-effective procedure with long-term benefits in all areas. With this consideration, myco synthesized silver nano particles (AgNPs) were studied and it acted as an impending corrosion inhibitor in the environment. Initially, AgNPs were evaluated by physical and surface characterizations and this evidence demonstrated that RYRE's water-soluble molecules played an essential role in the synthesis of AgNPs in nano spherical size. The myco synthesized of AgNPs has showed an antibacterial activity against corrosive bacteria in cooling water system (CWS). Hence, the AgNPs were used in biocorrosion studies as an anticorrosive agent along with AgNO3 and RYRE was also checked. For this experiment, the copper (Cu) metal (CW024) which is commonly used was selected, the result of corrosion rate was decreased, and inhibition efficiency (82%) was higher in the presence of AgNPs in system IV. Even though, AgNO3 and RYRE had contributed significant inhibition efficiency on Cu at 47% and 61%, respectively. According to XRD, the reaction of AgNPs on Cu metal resulted in the formation of a protective coating of Fe2O3 against corrosion. EIS data also indicated that it could reduce the corrosion on the Cu metal surface. All of these findings point out the possibility that the myco-synthesized AgNPs were an effective copper metal corrosion inhibitor. As a result, we encourage the development of myco-synthesized AgNPs, which could be useful in the industrial settings.}, } @article {pmid35688968, year = {2022}, author = {Hu, J and Gu, Y and Lu, H and Raheem, MA and Yu, F and Niu, X and Zuo, J and Yin, H and Huang, C and Song, X and Tu, J and Zhou, W and Jiang, W and Chen, Z and Han, X and Qi, K}, title = {Identification of novel biofilm genes in avian pathogenic Escherichia coli by Tn5 transposon mutant library.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {8}, pages = {130}, pmid = {35688968}, issn = {1573-0972}, support = {31872483//National Natural Science Foundation of China/ ; 31772707//National Natural Science Foundation of China/ ; 32072829//National Natural Science Foundation of China/ ; No.22ZR1475800//Natural Science Foundation of Shanghai/ ; No. 2021J011099//Natural Science Foundation of Fujian Province/ ; Grant No. 2021ZN001//Research Foundation for Advanced Talents of Ludong University/ ; }, mesh = {Animals ; Biofilms ; Chickens ; DNA-Binding Proteins ; Escherichia coli/metabolism ; *Escherichia coli Infections ; *Escherichia coli Proteins/genetics/metabolism ; Fimbriae Proteins/genetics ; Integrases ; *Poultry Diseases ; Transposases/*metabolism ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is the main pathogens that inflict the poultry industry. Biofilm as the pathogenic factors of APEC, which can enhance the anti-host immune system of APEC and improve its survival in the environment. In order to screen for new genes related to APEC biofilm. The APEC strain APEC81 was used to construct a mutant library by Tn5 insertion mutagenesis. Moreover the 28 mutant strains with severely weakened biofilm were successfully screened from 1500 mutant strains by crystal violet staining, in which 17 genes were obtained by high-efficiency thermal asymmetric interlaced PCR. The reported genes include 3 flagella genes (fliS, fliD, and fliR), 4 curli fimbriae genes (csgD, csgA, csgF, and csgG) and 3 type 1 fimbriae genes (fimA, fimD, and fimC). The novel genes include 3 coenzyme genes (gltA, bglX, and mltF) and 4 putative protein genes (yehE, 07045, 11735, 11255). To investigate whether these 17 genes co-regulate the biofilm, the 17 identified genes were deleted from APEC strain APEC81. The results showed that except for the 11735 and 11255 genes, the deletion of 15 genes significantly reduced the biofilm formation ability of APEC81 (P < 0.05). The result of rdar (red, dry and rough) colony morphology showed that curli fimbriae genes (csgD, csgA, csgF, and csgG) and other functional genes (fimC, glxK, yehE, 07045, and 11255) affected the colony morphology. In particular, the hypothetical protein YehE had the greatest influence on the biofilm. It was predicted to have the same structure as the type 1 fimbria protein. When yehE was deleted, the fimE transcription was up-regulated, and the fimA and fimB transcription were down-regulated, resulting in a decrease in type 1 fimbriae. Hence, the yehE mutant significantly reduced the biofilm and the adhesion and invasion ability to cells (P < 0.05). This study identified 5 novel genes (gltA, bglX, mltF, yehE, and 07045) related to biofilm formation and confirmed that yehE affects biofilm formation by type 1 fimbriae, which will benefit further study of the mechanism of biofilm regulation in APEC.}, } @article {pmid35688188, year = {2022}, author = {Ganesan, S and Limphattharachai, S and Chawengkijwanich, C and Liu, Y and Janjaroen, D}, title = {Influence of salinity on biofilm formation and COD removal efficiency in anaerobic moving bed biofilm reactors.}, journal = {Chemosphere}, volume = {304}, number = {}, pages = {135229}, doi = {10.1016/j.chemosphere.2022.135229}, pmid = {35688188}, issn = {1879-1298}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Salinity ; *Waste Disposal, Fluid/methods ; *Wastewater ; }, abstract = {Anaerobic digestion is widely used for wastewater treatment, but this approach often relies on microbial communities that are adversely affected by high-salinity conditions. This study investigated the applicability of an anaerobic moving bed biofilm reactor (AMBBR) to treating high-salinity wastewater. The removal performance and microbial community were examined under salinity conditions of 1000-3000 mg/L, and a soluble chemical oxygen demand (sCOD) removal efficiency of up to 8% ± 2.74% was achieved at high-salinity. Scanning electron microscopy showed that microorganisms successfully attached onto the polyvinyl alcohol gel carrier, and the extracellular polymeric substances on the biofilm increased at higher salt concentrations. The AMBBR also maintained traditionally accepted levels of total alkalinity and volatile fatty acids for stable wastewater processing under these operating conditions. High-throughput sequencing indicated that Desulfomicrobium and three methanogenic groups were the dominant contributors to sCOD removal. Overall, the results showed that the AMBBR can successfully treat fish factory wastewater under varying salinity conditions.}, } @article {pmid35687499, year = {2022}, author = {Li, J and Wu, Y and Zhang, Q and Zhao, J and Zhang, H and Chen, W}, title = {Optimization of environmental factors in a dual in vitro biofilm model of Candida albicans-Streptococcus mutans.}, journal = {Letters in applied microbiology}, volume = {75}, number = {4}, pages = {869-880}, doi = {10.1111/lam.13761}, pmid = {35687499}, issn = {1472-765X}, support = {JUFSTR20180102//Jiangsu Province/ ; 32021005//National Natural Science Foundation of China/ ; 32072197//National Natural Science Foundation of China/ ; }, mesh = {Amino Acids/metabolism ; Amino Sugars/metabolism ; Biofilms ; Candida albicans ; *Dental Caries ; Humans ; *Streptococcus mutans/metabolism ; Sucrose ; Virulence Factors/metabolism ; }, abstract = {The biofilm formation of Streptococcus mutans-Candida albicans is an important virulence factor for dental caries. The purpose of this study was to determine the effect of some environmental conditions on the biofilm formation like inoculation concentration, temperature, sugar, amino acid, metal ions and saliva, and then establish a persistent in vitro biofilm model for further research. Based on the single factor experiment, the factors participating in the biofilm formation including sugar, inoculation concentration, and saliva increased the biofilm mass, while amino acid, metal ions, temperatures reduced biofilm mass. Optimal conditions for biofilm formation were the inoculation dosage of S. mutans and C. albicans of 10[8] and 10[7] , respectively, the addition of 0·3 g l[-1] sucrose and sterile saliva. These results contribute to a deep understanding of the factors involved in oral biofilm formation of the important cariogenic pathogen S. mutans and the opportunistic pathogen C. albicans to study better for biofilm and promote the design of new therapeutic approaches. The present research also provides a model for evaluating the therapeutic potential for drugs in the future.}, } @article {pmid35686374, year = {2022}, author = {Mehrnia, MR and Nasiri, F and Pourasgharian Roudsari, F and Bahrami, F}, title = {Hybrid powdered activated carbon-activated sludge biofilm formation to mitigate biofouling in dynamic membrane bioreactor for wastewater treatment.}, journal = {Biofouling}, volume = {38}, number = {5}, pages = {415-426}, doi = {10.1080/08927014.2022.2081805}, pmid = {35686374}, issn = {1029-2454}, mesh = {Biofilms ; *Biofouling/prevention & control ; Bioreactors ; Charcoal ; Membranes, Artificial ; Powders ; Sewage ; Waste Disposal, Fluid/methods ; *Water Purification ; }, abstract = {Membrane costs and biofouling limit applications of membrane bioreactors (MBRs) for wastewater treatment. Here, powdered activated carbon (PAC) utilization in the formation and performance of a self-forming dynamic membrane consisting of activated sludge and PAC during hybrid wastewater treatment process was studied. Short-term agitation helped (non)biological particles to quickly uniformly settle on mesh filter, forming more uniform PAC-containing dynamic membranes (PAC-DMs). PAC adsorbed adhesive materials, resulting in an increase in average floc size and DM permeability while decreasing biofouling. The most efficient PAC concentration was 4 g L[-1] considering techno-economics, i.e. the highest effluent quality (turbidity of 19.89 NTU) and the lowest biofouling (transmembrane pressure rise of 2.89 mbar). Short-term performance of hybrid PAC-DM bioreactor (PAC-DMBR) showed stability in effluent quality improvement including 92%, 95%, 83%, 84% and 98% reductions in turbidity, chemical oxygen demand, total dissolved solids, total nitrogen, and total phosphorous, respectively. Accordingly, adopting hybrid PAC-DMBR has potential to alleviate biofouling and capital cost.}, } @article {pmid35686192, year = {2022}, author = {Qian, W and Li, X and Yang, M and Liu, C and Kong, Y and Li, Y and Wang, T and Zhang, Q}, title = {Relationship Between Antibiotic Resistance, Biofilm Formation, and Biofilm-Specific Resistance in Escherichia coli Isolates from Ningbo, China.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {2865-2878}, pmid = {35686192}, issn = {1178-6973}, abstract = {PURPOSE: Several Escherichia coli pathotypes still constitute an important public health concern owing to its pathogenicity and antimicrobial resistance. Moreover, biofilm formation of E. coli can allow the strains to interfere with host and antimicrobial eradication, thus conferring additional resistance. The association between the formation of biofilm and antimicrobial resistance determinants has been extensively exploited; nevertheless, there is still no definite conclusion. The purpose of this study was to provide additional data to augment the present knowledge about the subject.

METHODS: Antibiotic resistance/susceptibility profiles of 81 isolates from pediatric individuals in China between 2011 and 2014 against 20 antibiotics were assessed using the VITEK 2 system. Biofilm-forming capacities were evaluated using the crystal violet staining method, confocal laser scanning microscopy (CLSM), and field emission scanning electron microscopy. Biofilm compositions inside the biofilm formed by representative strains were assessed using CLSM. The effects of antibiotics on biofilms generated by E. coli strains of different biofilm-forming ability were examined using CLSM in combination with gatifloxacin. The relationships between antibiotic resistance, biofilm formation, and biofilm-specific resistance in E. coli isolates were investigated.

RESULTS: The results showed that 23 isolates were classified as multidrug-resistant, and 57 isolates were classified as extensively drug-resistant (XDR). Among the 69 isolates with the ability to form biofilms, 46 isolates were stronger biofilm formers. Correlation analysis demonstrated that strain populations exhibiting more robust biofilm formation likely contained larger proportions of XDR isolates.

CONCLUSION: Together, our study implies that there was an association between biofilm-formation and resistance to several antibiotics for XDR-E. coli isolates, and would provide novel insights regarding the prevention and treatment against E. coli-related infections.}, } @article {pmid35685939, year = {2022}, author = {Tan, Y and Ma, S and Ding, T and Ludwig, R and Lee, J and Xu, J}, title = {Enhancing the Antibiofilm Activity of β-1,3-Glucanase-Functionalized Nanoparticles Loaded With Amphotericin B Against Candida albicans Biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {815091}, pmid = {35685939}, issn = {1664-302X}, abstract = {Candida biofilm-related infections cause increased morbidity and mortality in patients with a reduced immune response. Traditional antifungal therapies have proven to be insufficient as the biofilm matrix acts as a perfusion barrier. Thus, novel methods are required to improve drug delivery and kill Candida within the biofilm. In this study, chitosan nanoparticles (CSNPs) loaded with Amphotericin B (AMB), which were functionalized with β-1,3-glucanase (Gls), were fabricated (CSNPs-AMB-Gls), and their antibiofilm activity against Candida albicans biofilm was evaluated in vitro. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were employed to examine biofilm architecture and cell viability. CSNPs-AMB-Gls inhibited planktonic cell growth and biofilm formation effectively and exhibited the highest efficacy on the removal of a mature biofilm than free AMB or CSNPs-AMB. The created nanoparticles (NPs) were found to penetrate the biofilm so as to directly interfere with the cells inside and disassemble the biofilm matrix. CSNPs-AMB-Gls could also eradicate biofilms from clinical isolates. These results suggest the potential applicability of CSNPs-AMB-Gls for the treatment of Candida biofilm-related infections.}, } @article {pmid35684540, year = {2022}, author = {Berkl, Z and Fekete-Kertész, I and Buda, K and Vaszita, E and Fenyvesi, É and Szente, L and Molnár, M}, title = {Effect of Cyclodextrins on the Biofilm Formation Capacity of Pseudomonas aeruginosa PAO1.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {11}, pages = {}, pmid = {35684540}, issn = {1420-3049}, support = {TKP2021-EGA-02//HUNGARIAN NATIONAL RESEARCH, DEVELOPMENT AND INNOVATION OFFICE/ ; K_17 Program (K_17 125093)//HUNGARIAN NATIONAL RESEARCH, DEVELOPMENT AND INNOVATION OFFICE/ ; }, mesh = {Biofilms ; *Cyclodextrins/pharmacology ; Humans ; Polymers/pharmacology ; *Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {Quorum sensing (QS) is a population-density-dependent communication process of microorganisms to coordinate their activities by producing and detecting low-molecular-weight signal molecules. In pathogenic bacteria, the property controlled by QS is often related to infectivity, e.g., biofilm formation. Molecular encapsulation of the QS signals is an innovative method to prevent the signals binding to the receptors and to attenuate QS. Cyclodextrins (CDs) may form an inclusion complex with the signals, thus reducing the communication (quorum quenching, QQ). A systematic study was performed with α-, β-cyclodextrin, and their random methylated, quaternary amino and polymer derivatives to evaluate and compare their effects on the biofilm formation of Pseudomonas aeruginosa. To examine the concentration-, temperature- and time-dependency of the QQ effect, the CDs were applied at a 0.1-12.5 mM concentration range, and biofilm formation was studied after 6, 24, 48 and 72 h at 22 and 30 °C. According to the results, the QS mechanism was significantly inhibited; the size of the cavity, the structure of the substituents, as well as the monomeric or polymeric character together with the concentration of the CDs have been identified as key influencing factors of biofilm formation. Statistically determined effective concentration values demonstrated outstanding efficiency (higher than 80% inhibition) of α-CD and its random methylated and polymer derivatives both on the short and long term. In summary, the potential value of CDs as inhibitors of QS should be considered since the inhibition of biofilm formation could significantly impact human health and the environment.}, } @article {pmid35684205, year = {2022}, author = {Ghazal, TSA and Schelz, Z and Vidács, L and Szemerédi, N and Veres, K and Spengler, G and Hohmann, J}, title = {Antimicrobial, Multidrug Resistance Reversal and Biofilm Formation Inhibitory Effect of Origanum majorana Extracts, Essential Oil and Monoterpenes.}, journal = {Plants (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {35684205}, issn = {2223-7747}, support = {K135845//National Research, Development and Innovation Office/ ; }, abstract = {Origanum majorana L. is a widely used medicinal plant; its distilled oil and preparations are extensively utilised in the phytotherapy and food industries. The objective of this study is to evaluate the extracts and the essential oil (EO) of Origanum majorana L, and its monoterpenes for antimicrobial, bacterial multidrug resistance reversing, and biofilm formation inhibitory potency. The composition of EO and n-hexane extract was characterized by GC-MS. In the essential oil terpinen-4-ol (24.92%), trans-sabinene hydrate (25.18%), γ-terpinene (6.48%), cis-sabinene hydrate (5.44%), p-cymene (4.72%), sabinene (4.53%), α-terpineol (4.43%), and α-terpinene (3.00%) were found as the main constituents while trans-sabinene hydrate (1.43%), and terpinen-4-ol (0.19%) were detected in the n-hexane extract besides a series of hydrocarbons. The antibacterial activity of EO and terpinen-4-ol, α-terpinene, and linalool was also assessed against sensitive and drug-resistant S. aureus, and E. coli strains with MIC values of 0.125-0.250% and 30-61 µM, respectively. In the efflux pump (EP) inhibitory assay, made by the ethidium bromide accumulation method in E. coli ATCC 25922, and AG100 and S. aureus ATCC 25923, and MRSA ATCC 43300 strains, EO exhibited substantial activity, especially in the E. coli ATCC 25922 strain. Among the EO constituents, only sabinene was an EP inhibitor in sensitive Escherichia strain. In the case of S. aureus strains, EO and sabinene hydrate exhibited moderate potency on the drug-resistant phenotype. The antibiofilm effects of the samples were tested by crystal violet staining at sub-MIC concentration. γ-Terpinene, terpinen-4-ol, sabinene, sabinene hydrate and linalool were found to be effective inhibitors of biofilm formation (inhibition 36-86%) on E. coli ATCC 25922 and S. aureus MRSA ATCC 43300, while EO was ineffective on these strains. In contrast to this, biofilms formed by E. coli AG100 and S. aureus ATCC 25923 were significantly inhibited by the EO; however, it was not affected by any of the monoterpenes. This observation suggests that the antibiofilm effect might be altered by the synergism between the components of the essential oil.}, } @article {pmid35684202, year = {2022}, author = {Adeosun, IJ and Baloyi, IT and Cosa, S}, title = {Anti-Biofilm and Associated Anti-Virulence Activities of Selected Phytochemical Compounds against Klebsiella pneumoniae.}, journal = {Plants (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {35684202}, issn = {2223-7747}, support = {Self-Initiated Research//South African Medical Research Council/ ; }, abstract = {The ability of Klebsiella pneumoniae to form biofilm renders the pathogen recalcitrant to various antibiotics. The difficulty in managing K. pneumoniae related chronic infections is due to its biofilm-forming ability and associated virulence factors, necessitating the development of efficient strategies to control virulence factors. This study aimed at evaluating the inhibitory potential of selected phytochemical compounds on biofilm-associated virulence factors in K. pneumoniae, as well as authenticating their antibiofilm activity. Five phytochemical compounds (alpha-terpinene, camphene, fisetin, glycitein and phytol) were evaluated for their antibacterial and anti-biofilm-associated virulence factors such as exopolysaccharides, curli fibers, and hypermucoviscosity against carbapenem-resistant and extended-spectrum beta-lactamase-positive K. pneumoniae strains. The antibiofilm potential of these compounds was evaluated at initial cell attachment, microcolony formation and mature biofilm formation, then validated by in situ visualization using scanning electron microscopy (SEM). Exopolysaccharide surface topography was characterized using atomic force microscopy (AFM). The antibacterial activity of the compounds confirmed fisetin as the best anti-carbapenem-resistant K. pneumoniae, demonstrating a minimum inhibitory concentration (MIC) value of 0.0625 mg/mL. Phytol, glycitein and α-terpinene showed MIC values of 0.125 mg/mL for both strains. The assessment of the compounds for anti-virulence activity (exopolysaccharide reduction) revealed an up to 65.91% reduction in phytol and camphene. Atomic force microscopy detected marked differences between the topographies of untreated and treated (camphene and phytol) exopolysaccharides. Curli expression was inhibited at both 0.5 and 1.0 mg/mL by phytol, glycitein, fisetin and quercetin. The hypermucoviscosity was reduced by phytol, glycitein, and fisetin to the shortest mucoid string (1 mm) at 1 mg/mL. Phytol showed the highest antiadhesion activity against carbapenem-resistant and extended-spectrum beta-lactamase-positive K. pneumoniae (54.71% and 50.05%), respectively. Scanning electron microscopy correlated the in vitro findings, with phytol significantly altering the biofilm architecture. Phytol has antibiofilm and antivirulence potential against the highly virulent K. pneumoniae strains, revealing it as a potential lead compound for the management of K. pneumoniae-associated infections.}, } @article {pmid35683049, year = {2022}, author = {Petrović, M and Randjelović, M and Igić, M and Randjelović, M and Arsić Arsenijević, V and Mionić Ebersold, M and Otašević, S and Milošević, I}, title = {Poly(methyl methacrylate) with Oleic Acid as an Efficient Candida albicans Biofilm Repellent.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {11}, pages = {}, pmid = {35683049}, issn = {1996-1944}, support = {No. 2014.0040/Serbia/OP.//Swiss Government Excellence Scholarship/ ; }, abstract = {Poly(methyl methacrylate) (PMMA), widely used in dentistry, is unfortunately a suitable substrate for Candida (C.) albicans colonization and biofilm formation. The key step for biofilm formation is C. albicans ability to transit from yeast to hypha (filamentation). Since oleic acid (OA), a natural compound, prevents filamentation, we modified PMMA with OA aiming the antifungal PMMA_OA materials. Physico-chemical properties of the novel PMMA_OA composites obtained by incorporation of 3%, 6%, 9%, and 12% OA into PMMA were characterized by Fourier-transform infrared spectroscopy and water contact angle measurement. To test antifungal activity, PMMA_OA composites were incubated with C. albicans and the metabolic activity of both biofilm and planktonic cells was measured with a XTT test, 0 and 6 days after composites preparation. The effect of OA on C. albicans morphology was observed after 24 h and 48 h incubation in agar loaded with 0.0125% and 0.4% OA. The results show that increase of OA significantly decreased water contact angle. Metabolic activity of both biofilm and planktonic cells were significantly decreased in the both time points. Therefore, modification of PMMA with OA is a promising strategy to reduce C. albicans biofilm formation on denture.}, } @article {pmid35682576, year = {2022}, author = {Puhm, M and Hendrikson, J and Kivisaar, M and Teras, R}, title = {Pseudomonas putida Biofilm Depends on the vWFa-Domain of LapA in Peptides-Containing Growth Medium.}, journal = {International journal of molecular sciences}, volume = {23}, number = {11}, pages = {}, pmid = {35682576}, issn = {1422-0067}, support = {PRG707//Estonian Research Council/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Peptides/metabolism ; *Pseudomonas putida/genetics/metabolism ; }, abstract = {The biofilm of Pseudomonas putida is complexly regulated by several intercellular and extracellular factors. The cell surface adhesin LapA of this bacterium is a central factor for the biofilm and, consequently, the regulation of lapA expression, for example, by Fis. It has been recently shown that peptides in growth media enhance the formation of P. putida biofilm, but not as a source of carbon and nitrogen. Moreover, the peptide-dependent biofilm appeared especially clearly in the fis-overexpression strain, which also has increased LapA. Therefore, we investigate here whether there is a relationship between LapA and peptide-dependent biofilm. The P. putida strains with inducible lapA expression and LapA without the vWFa domain, which is described as a domain similar to von Willebrand factor domain A, were constructed. Thereafter, the biofilm of these strains was assessed in growth media containing extracellular peptides in the shape of tryptone and without it. We show that the vWFa domain in LapA is necessary for biofilm enhancement by the extracellular peptides in the growth medium. The importance of vWFa in LapA was particularly evident for the fis-overexpression strain F15. The absence of the vWFa domain diminished the positive effect of Fis on the F15 biofilm.}, } @article {pmid35681328, year = {2022}, author = {Wang, L and Ju, X and Cong, Y and Lin, H and Wang, J}, title = {A Single Catalytic Endolysin Domain Plychap001: Characterization and Application to Control Vibrio parahaemolyticus and Its Biofilm Directly.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {35681328}, issn = {2304-8158}, support = {31870166//National Natural Science Foundation of China/ ; CARS-47//China Agriculture Research System/ ; }, abstract = {Endolysins are enzymes used by bacteriophages to cleave the host cell wall in the final stages of the lytic cycle. As such, they are considered promising antibacterial agents for controlling and combating multidrug-resistant (MDR) bacteria. However, the application of endolysins targeting Gram-negative bacteria is greatly hindered by the outer membrane on these bacteria. Lysqdvp001, an endolysin with modular structure, has been reported as one of the most efficient endolysins against the Gram-negative bacterium Vibrio parahaemolyticus. In this study, Plychap001, the truncated recombinant catalytic domain of Lysqdvp001, was demonstrated to exhibit a direct and efficient bactericidal activity against broad spectrum of V. parahaemolyticus strains. Plychap001 was shown to be highly stable and retain high bactericidal activity at high temperatures, over a wide pH range, and at high NaCl concentrations. Plychap001 also exhibited a synergistic lytic effect with EDTA. Additionally, Plychap001 was found to efficiently degrade and eliminate V. parahaemolyticus biofilms on polystyrene surfaces. Our study establishes Plychap001 as a promising method for controlling V. parahaemolyticus in the food industry.}, } @article {pmid35678575, year = {2022}, author = {Sharma, N and Das, A and Raja, P and Marathe, SA}, title = {The CRISPR-Cas System Differentially Regulates Surface-Attached and Pellicle Biofilm in Salmonella enterica Serovar Typhimurium.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0020222}, pmid = {35678575}, issn = {2165-0497}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; CRISPR-Cas Systems ; Cellulose/metabolism ; *Gene Expression Regulation, Bacterial ; Lipopolysaccharides/metabolism ; *Salmonella typhimurium/metabolism ; Serogroup ; }, abstract = {The CRISPR-Cas mediated regulation of biofilm by Salmonella enterica serovar Typhimurium was investigated by deleting CRISPR-Cas components ΔcrisprI, ΔcrisprII, ΔΔcrisprI crisprII, and Δcas op. We determined that the system positively regulates surface biofilm while inhibiting pellicle biofilm formation. Results of real-time PCR suggest that the flagellar (fliC, flgK) and curli (csgA) genes were repressed in knockout strains, causing reduced surface biofilm. The mutants displayed altered pellicle biofilm architecture. They exhibited bacterial multilayers and a denser extracellular matrix with enhanced cellulose and less curli, ergo weaker pellicles than those of the wild type. The cellulose secretion was more in the knockout strains due to the upregulation of bcsC, which is necessary for cellulose export. We hypothesized that the secreted cellulose quickly integrates into the pellicle, leading to enhanced pellicular cellulose in the knockout strains. We determined that crp is upregulated in the knockout strains, thereby inhibiting the expression of csgD and, hence, also of csgA and bcsA. The conflicting upregulation of bcsC, the last gene of the bcsABZC operon, could be caused by independent regulation by the CRISPR-Cas system owing to a partial match between the CRISPR spacers and bcsC gene. The cAMP-regulated protein (CRP)-mediated regulation of the flagellar genes in the knockout strains was probably circumvented through the regulation of yddx governing the availability of the sigma factor σ[28] that further regulates class 3 flagellar genes (fliC, fljB, and flgK). Additionally, the variations in the lipopolysaccharide (LPS) profile and expression of LPS-related genes (rfaC, rfbG, and rfbI) in knockout strains could also contribute to the altered pellicle architecture. Collectively, we establish that the CRISPR-Cas system differentially regulates the formation of surface-attached and pellicle biofilm. IMPORTANCE In addition to being implicated in bacterial immunity and genome editing, the CRISPR-Cas system has recently been demonstrated to regulate endogenous gene expression and biofilm formation. While the function of individual cas genes in controlling Salmonella biofilm has been explored, the regulatory role of CRISPR arrays in biofilm is less studied. Moreover, studies have focused on the effects of the CRISPR-Cas system on surface-associated biofilms, and comprehensive studies on the impact of the system on pellicle biofilm remain an unexplored niche. We demonstrate that the CRISPR array and cas genes modulate the expression of various biofilm genes in Salmonella, whereby surface and pellicle biofilm formation is distinctively regulated.}, } @article {pmid35677656, year = {2022}, author = {Su, FJ and Periyasamy, T and Chen, MM}, title = {Comparative Transcriptomic Immune Responses of Mullet (Mugil cephalus) Infected by Planktonic and Biofilm Lactococcus Garvieae.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {887921}, pmid = {35677656}, issn = {2235-2988}, mesh = {Animals ; *Bacterial Infections ; Biofilms ; *Fish Diseases/microbiology ; Immunity, Innate ; Lactococcus ; Plankton/genetics ; *Smegmamorpha/genetics ; Transcriptome ; }, abstract = {Lactococcus garvieae is an important pathogen of fish, associated with high rates of mortality and infection recurrence in summer or stressful conditions. Chronic infection and disease recurrence have also been reported to be associated with biofilms. However, the impact of biofilm and planktonic bacterial infection on fish immune responses remains unclear. In this study, de novo sequencing was used to compare differences of the spleen transcriptome in planktonic- and biofilm-infected mullets. Among the 181,024 unigenes obtained, 3,392 unigenes were associated with immune response genes. Comparative analysis of the gene expression between infection with the L. garvieae planktonic type and biofilm type identified a total of 3,120 and 3,489 differentially expressed genes in response to planktonic and biofilm infection, respectively, of which 1,366 and 1,458 genes were upregulated, and 1,754 and 1,458 genes were downregulated, respectively. Gene ontology enrichment analysis of immune genes identified genes involved in the complement system, toll-like receptor signaling, and antigen processing, which were further verified by qPCR. Additionally, genes encoding TLR2, IL-1β, TNF-α, C7, and MHC class II peptides were downregulated in response to biofilm infection. Importantly, the results show that biofilm infection induces a different immune pathway response compared with planktonic bacterial infection and, furthermore, illustrates that the prevention of biofilm formation may be a necessary and new strategy for controlling bacterial infection in aquaculture.}, } @article {pmid35676766, year = {2022}, author = {Dong, F and Liu, S and Zhang, D and Zhang, J and Wang, X}, title = {Matrix-producing cells formed 'Van Gogh bundles' facilitate Bacillus subtilis biofilm self-healing.}, journal = {Environmental microbiology reports}, volume = {14}, number = {5}, pages = {822-827}, doi = {10.1111/1758-2229.13099}, pmid = {35676766}, issn = {1758-2229}, mesh = {*Bacillus subtilis/genetics ; Biofilms ; *Paintings ; Phenotype ; }, abstract = {Biofilms grow and expand through cell differentiation into various phenotypes, which have different functions and cooperate with each other. In our experiments, we find that biofilms can heal after damaged, and we also find there is a special structure near the cut, which is called the 'Van Gogh bundles' by Jordi et al. because of its resemblance to Van Gogh's famous painting 'The Starry Night'. Here, we study the 'Van Gogh bundles' structure evolution near the cut area, and how 'Van Gogh bundles' structure facilitates the cut healing by observing microscopic images of bacterial colonies growing from wild-type and mutant strains. We find that the amount of matrix-producing cells contributes to the 'Van Gogh bundles' structure, such as curvature. Through the comparison of curvatures of 'Van Gogh bundles' and the rate of the cut healing, we find that the smaller the curvature, the faster healing rate. To better explain the above experiment observations, we establish an individual-based model and simulate the formation and growth of 'Van Gogh bundles' along the cut by giving rules for an individual cell like cell growth, division and turning rules, and also 'Van Gogh bundles' fold division rule.}, } @article {pmid35676463, year = {2022}, author = {Zarei, M and Bahrami, S and Liljebjelke, K}, title = {Biofilm formation of Salmonella enterica serovar Enteritidis cocultured with Acanthamoeba castellanii responds to nutrient availability.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {4}, pages = {691-700}, pmid = {35676463}, issn = {1618-1905}, mesh = {*Acanthamoeba castellanii ; Biofilms ; Carbohydrates ; Coculture Techniques ; Culture Media ; Nutrients ; *Salmonella enteritidis/genetics ; }, abstract = {Acanthamoeba spp. and Salmonella share common habitats, and their interaction may influence the biofilm-forming ability of Salmonella. In this study, biofilm formation of Salmonella enterica serovar Enteritidis cocultured with Acanthamoeba castellanii was examined in nutrient-rich and nutrient-deficient media. Furthermore, transcript copy number of biofilm-related genes in the biofilm cells of S. Enteritidis in monoculture was compared to those in coculture with A. castellanii. Results demonstrated that the presence of A. castellanii in the culture media activates the genes involved in the biofilm formation of S. Enteritidis, regardless of the nutrient availability. However, biofilm formation of S. Enteritidis cocultured with A. castellanii was not consistent with the transcript copy number results. In nutrient-rich medium, the number of Salmonella biofilm cells and the contents of the three main components of the biofilms including eDNA, protein, and carbohydrates were higher in the presence of A. castellanii compared to monocultures. However, in nutrient-deficient medium, the number of biofilm cells, and the amount of biofilm components in coculture conditions were less than the monocultures. These results indicate that despite activation of relevant genes in both nutrient-rich and nutrient-deficient media, biofilm formation of S. Enteritidis cocultured with A. castellanii responds to nutrient availability.}, } @article {pmid35676412, year = {2022}, author = {Aziz, SAAA and Mahmoud, R and Mohamed, MBED}, title = {Control of biofilm-producing Pseudomonas aeruginosa isolated from dairy farm using Virokill silver nano-based disinfectant as an alternative approach.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {9452}, pmid = {35676412}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Disinfectants/pharmacology ; Farms ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Silver/pharmacology ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is an important opportunistic pathogen that is responsible for many clinical infections in both animals and humans. This study aimed to detect the prevalence of P. aeruginosa in dairy farm's that possess a great importance to dairy industry where it shares in milk spoilage. Evaluation of the efficacy of commonly used disinfectants to control the pathogen in dairy environment and finding a way to overcome high resistance to the used agents. Samples (n = 250) were collected from different environmental components, milk, and milkers' hands. Pathogens were isolated, biofilm was detected and their sensitivity against two commonly used disinfectants and against silver nanoparticles and Virokill AgNPs at different concentrations and contact times were tested. The pathogen significantly prevailed in milk samples (70.0%, P < 0.001). 50 out 74 isolates were biofilm-forming that was significantly obtained from environment (71.8%, P < 0.001). P. aeruginosa showed variable degree of resistance to tested disinfectants but it was significantly sensitive to Virokill AgNPs (200/1000) mg/l at exposure time 24 h (P < 0.001). It was concluded that using Virokill AgNPs in regular sanitation and disinfection of dairy farms, this helps the control of P. aeruginosa subsequently increasing milk quality and improving dairy industry and protecting human health.}, } @article {pmid35674583, year = {2022}, author = {Borges, EL and Amorim, GL and Miranda, MB and Martins, FDS and Guedes, ACM and Sampaio, KH and Spira, JAO and Barcelos, LDS}, title = {Biofilm model on mice skin wounds.}, journal = {Acta cirurgica brasileira}, volume = {37}, number = {3}, pages = {e370306}, pmid = {35674583}, issn = {1678-2674}, mesh = {Animals ; Biofilms ; Mice ; Mice, Inbred C57BL ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa ; *Wound Infection/microbiology ; }, abstract = {PURPOSE: To evaluate a biofilm model of Pseudomonas aeruginosa in excisional cutaneous wound in mice.

METHODS: Preclinical, translational study conducted with 64 C57BL/6 mice randomly assigned to control and intervention groups. Evaluation was on days D0, D3, D5, D7 and D10 of wound making. The profile of biofilm formation and induction was evaluated using wound closure kinetics, quantitative culture, and evaluation of wounds using transmission electron microscopy (TEM). Clinical evaluation was performed by liver tissue culture, weight variation, and quantification of leukocytes in peripheral blood. Analyses were performed with GraphPad Prism software.

RESULTS: Bacterial load for induction of infection with P. aeruginosa and survival of animals was 104 UFC·mL-1. In D5 (p < 0.0001) and D7 (p < 0.01), animals in the intervention group showed a delay in the healing process and had their wounds covered by necrotic tissue until D10. Statistical differences were observed in wound cultures and weight at D5 and D7 (p < 0.01). Liver cultures and leukocyte quantification showed no statistical differences. No bacteria in planktonic or biofilm form were identified by TEM.

CONCLUSIONS: The findings raise questions about the understanding of the ease of formation and high occurrence of biofilm in chronic wounds.}, } @article {pmid35673888, year = {2022}, author = {Pan, M and Lu, C and Zheng, M and Zhou, W and Song, F and Chen, W and Yao, F and Liu, D and Cai, J}, title = {Unnatural Amino-Acid-Based Star-Shaped Poly(l-Ornithine)s as Emerging Long-Term and Biofilm-Disrupting Antimicrobial Peptides to Treat Pseudomonas aeruginosa-Infected Burn Wounds.}, journal = {Advanced healthcare materials}, volume = {11}, number = {11}, pages = {e2200944}, doi = {10.1002/adhm.202200944}, pmid = {35673888}, issn = {2192-2659}, } @article {pmid35672892, year = {2022}, author = {Du, Z and Qiao, L and Yang, W and Chen, Y and Zhang, Y and Wu, W and Li, J and Wang, W and Cui, L and Chen, S}, title = {A multicenter, double-blind, placebo-controlled parallel study to evaluate the role of Yinhua Miyanling tablets in the prevention of bacterial biofilm formation on ureteral stents: a randomised trial.}, journal = {Annals of palliative medicine}, volume = {11}, number = {5}, pages = {1752-1761}, doi = {10.21037/apm-22-324}, pmid = {35672892}, issn = {2224-5839}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Drug-Related Side Effects and Adverse Reactions/etiology ; Humans ; Postoperative Complications/etiology ; *Stents/adverse effects/microbiology ; Tablets ; }, abstract = {BACKGROUND: Yinhua Miyanling tablet (YMT) not only has the functions of clearing away heat and toxin, dredging drenching and diuresis, but also has antibacterial activity. The formation of bacterial biofilm in ureteral stent and its related infection have plagued the clinic. Antibacterial traditional Chinese medicine is a potential method.

METHODS: This multicenter, randomized, double-blind, placebo-controlled study was designed to enroll patients who underwent ureteroscopic lithotripsy associated with indwelling ureteral stents at six centers between March 2019 and June 2020. The eligible patients were randomly assigned to the experimental group to take YMT 2 g qid orally or the control group to take dummy YMT 2 g qid orally from the first day after the operation according to a random number table. The unused drugs were recalled 14±3 days after the operation and record the body temperature. Relevant laboratory tests (urinalysis and urine culture) were performed before extubation. The ureteral stent was removed. The specimen was collected for scanning electron microscopy (SEM). Biofilm formation, USSQ scores, postoperative infectious complications, stone formation, and adverse drug reactions were compared between the two groups.

RESULTS: Of the 211 patients enrolled, 165 were included in the per-protocol set (PPS), including 86 in the control group and 79 in the experimental group. No significant difference was found between the two groups in baseline parameters (P>0.05). The prevalence of biofilm formation in the control group (47%) was significantly higher than that in the experimental group (22.7%, P=0.001). There was no significant difference in total USSQ score and domain score between the two groups (all P>0.05). There were more patients with symptomatic urinary tract infection (UTI) in the control group (12.9%) than in the experimental group (2.6%, P=0.017). The incidence of other complications did not show a significant difference between the two groups (all P>0.05). The incidence of stone formation on the ureteral stent surface and adverse drug reactions did not show a significant difference between the two groups (all P>0.05).

CONCLUSIONS: YMT is helpful to reduce the formation of bacterial biofilms on ureteral stents and the incidence of symptomatic UTIs related to ureteral stenting after surgery for ureteral calculi.

TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000041399.}, } @article {pmid35671532, year = {2022}, author = {Teschler, JK and Nadell, CD and Drescher, K and Yildiz, FH}, title = {Mechanisms Underlying Vibrio cholerae Biofilm Formation and Dispersion.}, journal = {Annual review of microbiology}, volume = {76}, number = {}, pages = {503-532}, doi = {10.1146/annurev-micro-111021-053553}, pmid = {35671532}, issn = {1545-3251}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R01 AI114261/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/metabolism ; *Biofilms/growth & development ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial ; Transcription Factors/metabolism ; *Vibrio cholerae/genetics/physiology ; }, abstract = {Biofilms are a widely observed growth mode in which microbial communities are spatially structured and embedded in a polymeric extracellular matrix. Here, we focus on the model bacterium Vibrio cholerae and summarize the current understanding of biofilm formation, including initial attachment, matrix components, community dynamics, social interactions, molecular regulation, and dispersal. The regulatory network that orchestrates the decision to form and disperse from biofilms coordinates various environmental inputs. These cues are integrated by several transcription factors, regulatory RNAs, and second-messenger molecules, including bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Through complex mechanisms, V. cholerae weighs the energetic cost of forming biofilms against the benefits of protection and social interaction that biofilms provide.}, } @article {pmid35671527, year = {2022}, author = {Hill, DL and Castiaux, A and Pensler, E and Knue, J and Attar, PS and Siddiqi, A}, title = {A Novel Activated Zinc Solution with Improved Efficacy Against Pseudomonas and MRSA Biofilm Compared to Chlorhexidine and Povidone-Iodine.}, journal = {Surgical technology international}, volume = {41}, number = {}, pages = {}, doi = {10.52198/22.STI.41.SO1595}, pmid = {35671527}, issn = {1090-3941}, abstract = {INTRODUCTION: The search for the optimal agent for infection eradication in periprosthetic joint infection (PJI) remains challenging as there are limited efficacious and safe options. The ideal solution should have significant bactericidal and anti-biofilm activity to be able to eradicate infection with the preservation of prosthetic components. Therefore, the purpose of this study was to 1) investigate the anti-biofilm efficacy of a novel activated zinc solution against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) biofilm in vitro and 2) compare its efficacy against two leading commercially available antimicrobial irrigants (CHG and 0.35% povidone-iodine [PI]).

MATERIALS AND METHODS: A modified Robbins device (MRD) was utilized to replicate Pseudomonas aeruginosa and MRSA biofilms. The primary outcome was to determine bacterial reduction after two hours of biofilm exposure to an activated zinc solution, CHG, and PI, and compare to untreated controls.

RESULTS: Against Pseudomonas biofilm, activated zinc demonstrated a 4.5-log (99.996%) reduction, chlorhexidine demonstrated a 0.9-log (87.4%) reduction (p<0.001), and PI demonstrated a 0.8-log (83.1%) reduction (p<0.001). After two hours of exposure, activated zinc had undetectable MRSA with a 7.08-log (100%) reduction, chlorhexidine had a 1.9-log (98.7%) reduction (p<0.01), and PI had a 3.2-log (99.9%) reduction (p<0.01).

CONCLUSIONS: Our novel activated zinc compound demonstrated a 99.996% reduction in Pseudomonas biofilm and a 100% reduction in MRSA biofilm. This novel solution may provide a significant tool in the arsenal to treat and/or prevent PJI and other wound infections. Future in vivo studies are warranted to demonstrate clinical utility, efficacy, and safety.}, } @article {pmid35671186, year = {2022}, author = {Wang, L and Tao, Z and Lu, B}, title = {Biofilm formation and invasive ability contribute to CC17 serotype III group B Streptococcus virulence.}, journal = {Chinese medical journal}, volume = {135}, number = {7}, pages = {869-871}, pmid = {35671186}, issn = {2542-5641}, mesh = {Biofilms ; Humans ; Multilocus Sequence Typing ; Serogroup ; *Streptococcal Infections ; *Streptococcus agalactiae/genetics ; Virulence ; }, } @article {pmid35670600, year = {2022}, author = {Jiang, Y and Liang, C and Zhao, W and Chen, T and Yu, B and Hou, A and Zhu, J and Zhang, T and Liu, Q and Ying, H and Liu, D and Sun, W and Chen, Y}, title = {Cell Cycle Progression Influences Biofilm Formation in Saccharomyces cerevisiae 1308.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0276521}, pmid = {35670600}, issn = {2165-0497}, mesh = {Biofilms ; Cell Division ; *Ethanol/metabolism ; Fermentation ; Polysaccharides ; *Saccharomyces cerevisiae ; }, abstract = {Biofilm-immobilized continuous fermentation is a novel fermentation strategy that has been utilized in ethanol fermentation. Continuous fermentation contributes to the self-proliferation of Saccharomyces cerevisiae biofilms. Previously, we successfully described the cell cycle differences between biofilm-immobilized fermentation and calcium alginate-immobilized fermentation. In the present study, we investigated the relationship between biofilm formation and the cell cycle. We knocked down CLN3, SIC1, and ACE2 and found that Δcln3 and Δsic1 exhibited a predominance of G2/M phase cells, increased biofilm formation, and significantly increased extracellular polysaccharide formation and expression of genes in the FLO gene family during immobilisation fermentation. Δace2 exhibited a contrasting performance. These findings suggest that the increase in the proportion of cells in the G2/M phase of the cell cycle facilitates biofilm formation and that the cell cycle influences biofilm formation by regulating cell adhesion and polysaccharide formation. This opens new avenues for basic research and may also help to provide new ideas for biofilm prevention and optimization. IMPORTANCE Immobilised fermentation can be achieved using biofilm resistance, resulting in improved fermentation efficiency and yield. The link between the cell cycle and biofilms deserves further study since reports are lacking in this area. This study showed that the ability of Saccharomyces cerevisiae to produce biofilm differed when cell cycle progression was altered. Further studies suggested that cell cycle regulatory genes influenced biofilm formation by regulating cell adhesion and polysaccharide formation. Findings related to cell cycle regulation of biofilm formation set the stage for biofilm in Saccharomyces cerevisiae and provide a theoretical basis for the development of a new method to improve biofilm-based industrial fermentation.}, } @article {pmid35669826, year = {2022}, author = {Nabizadeh Nodehi, R and Golpayegani, A and Douraghi, M and Alimohammadi, M and Rezaei, F}, title = {Novel application of in vitro disinfection for modeling the biofilm formation inhibition, antimicrobial susceptibility and antibiotic resistance of Pseudomonas aeruginosa: a study of free and combined chlorine compounds.}, journal = {Journal of environmental health science & engineering}, volume = {20}, number = {1}, pages = {167-180}, pmid = {35669826}, issn = {2052-336X}, abstract = {Biofilm formation and antibiotic resistance are the most important ways in which water bacteria such as Pseudomonas aeruginosa are protected against antibacterial agents. The aim of this study was to develop a rapid and cost-effective laboratory method for modeling and optimizing chlorine disinfection conditions. Critical factors (disinfection type, concentration, contact time and pH) were tested on bactericidal effect, inhibition of biofilm formation (IBF) and antibiotic susceptibility (AS) of P. aeruginosa. The central composite face-centered (CCF) design was applied to model the effect of disinfection process on the IBF and AS. The results showed that the IBF response was more affected by the strain type of P. aeruginosa and the type of disinfectant, which may be due to previous species growth conditions of the standard strain and greater durability of CAT in water. Optimization of factors affecting disinfection had a significant effect on the planktonic form, but was not effective in removing the biofilm of P. aeruginosa. Furthermore, the concentration of NaOCl and CAT was more effective than pH on planktonic and biofilm cells inactivation. The model of AS was weaker than other models due to limited contact time and use of high concentrations of disinfectant. The use of chlorine compounds based on the recommended levels in water does not prevent the formation of P. aeruginosa biofilm. According to the optimization findings, although increasing the contact time and concentration of the disinfectant increases the bactericidal effect of chlorine, it can also increase the resistance of P. aeruginosa to some antibiotics.}, } @article {pmid35668859, year = {2022}, author = {Amankwah, S and Adisu, M and Gorems, K and Abdella, K and Kassa, T}, title = {Assessment of Phage-Mediated Inhibition and Removal of Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Medical Implants.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {2797-2811}, pmid = {35668859}, issn = {1178-6973}, abstract = {PURPOSE: Despite the growing interest in bacteriophage (phage) usage for the prevention, control, and removal of bacterial biofilms, few scientific data exist on phage applications on medical implant surfaces, while none exists on multiple implants. In this study, we aimed to isolate, biophysically characterize and assess phages as potential antibiofilm agents to inhibit and remove multidrug-resistant (MDR) Pseudomonas aeruginosa biofilm on catheter and endotracheal tube surfaces.

METHODS: The well-identified stored clinical isolates (n = 7) of MDR P. aeruginosa were obtained from Jimma Medical Center. Specific phages were isolated and characterized based on standard protocols. The phages were tested for their antibiofilm effects in preventing colonization and removing preformed biofilms of MDR P. aeruginosa, following phage coating and treatment of catheter and endotracheal tube segments.

RESULTS: Two P. aeruginosa-specific phages (ΦJHS-PA1139 and ΦSMK-PA1139) were isolated from JMC compound sewage sources. The phages were biophysically characterized as being thermally stable up to 40°C and viable between pH 4.0 and 11.0. The two phages tested against clinical MDR strains of P. aeruginosa showed broad host ranges but not on other tested bacterial species. Both phages reduced MDR bacterial biofilms during the screening step. The phage-coated segments showed 1.2 log10 up to 3.2 log10 inhibition relative to non-coated segments following 6 h coating of segments prior to microbial load exposure. In both phages, 6 h treatment of the segments with 10[6] PFU/mL yielded 1.0 log10 up to 1.6 log10 reductions for ΦJHS and 1.6 log10 up to 2.4 log10 reductions for ΦSMK.

CONCLUSION: Our results suggest that phages have great potential to serve the dual purpose as surface coating agents for preventing MDR bacterial colonization in medical implants and as biofilm removal agents in implant-associated infections.}, } @article {pmid35668756, year = {2022}, author = {Abdelraheem, WM and Refaie, MMM and Yousef, RKM and Abd El Fatah, AS and Mousa, YM and Rashwan, R}, title = {Assessment of Antibacterial and Anti-biofilm Effects of Vitamin C Against Pseudomonas aeruginosa Clinical Isolates.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {847449}, pmid = {35668756}, issn = {1664-302X}, abstract = {There is a persistent need to look for alternative therapeutic modalities to help control the pandemic of antimicrobial resistance. Assessment of antibacterial and anti-biofilm effects of vitamin C (ascorbic acid) was the aim of the current study. The micro-dilution method determined the minimal inhibitory concentration (MIC) of ascorbic acid or antibiotics alone and in combinations against Pseudomonas aeruginosa (P. aeruginosa) clinical isolates. The micro-titer plate method monitored the effect of ascorbic acid on the biofilm-producing isolates of P. aeruginosa. The effect of ascorbic acid on the differential expression of different antibiotic-resistant genes and biofilm encoding genes of P. aeruginosa isolates were also tested using real-time polymerase chain reaction (PCR). For in vivo assessment of the antibacterial effects of ascorbic acid alone or combined with an antibiotic, rats were infected with P. aeruginosa clinical isolate followed by different treatment regimens. MICs of ascorbic acid among P. aeruginosa isolates were in the range of 156.2-1,250 μg/ml, while MIC50 and MIC90 were 312.5 and 625 μg/ml, respectively. At sub-inhibitory concentrations (19.5-312.5 μg/ml), ascorbic acid had 100% biofilm inhibitory effect. Furthermore, ascorbic acid-treated bacteria showed downregulation of genes underpinning biofilm formation and antibiotic resistance. In vivo assessment of vitamin C and ceftazidime in rats showed that administration of both at a lower dose for treatment of pseudomonas infection in rats had a synergistic and more powerful effect. Vitamin C shows excellent in vitro results as an antibacterial and anti-biofilm agent. Vitamin C should be routinely prescribed with antibiotics to treat bacterial infections in the clinical setting.}, } @article {pmid35668112, year = {2022}, author = {Berlanga-Clavero, MV and Molina-Santiago, C and Caraballo-Rodríguez, AM and Petras, D and Díaz-Martínez, L and Pérez-García, A and de Vicente, A and Carrión, VJ and Dorrestein, PC and Romero, D}, title = {Bacillus subtilis biofilm matrix components target seed oil bodies to promote growth and anti-fungal resistance in melon.}, journal = {Nature microbiology}, volume = {7}, number = {7}, pages = {1001-1015}, pmid = {35668112}, issn = {2058-5276}, support = {R01 GM107550/GM/NIGMS NIH HHS/United States ; P41 GM103484/GM/NIGMS NIH HHS/United States ; DP2 GM137413/GM/NIGMS NIH HHS/United States ; R03 CA211211/CA/NCI NIH HHS/United States ; }, mesh = {*Bacillus subtilis/metabolism ; *Cucurbitaceae/microbiology ; Extracellular Polymeric Substance Matrix ; Lipid Droplets ; Seeds/microbiology ; }, abstract = {Beneficial microorganisms are used to stimulate the germination of seeds; however, their growth-promoting mechanisms remain largely unexplored. Bacillus subtilis is commonly found in association with different plant organs, providing protection against pathogens or stimulating plant growth. We report that application of B. subtilis to melon seeds results in genetic and physiological responses in seeds that alter the metabolic and developmental status in 5-d and 1-month-old plants upon germination. We analysed mutants in different components of the extracellular matrix of B. subtilis biofilms in interaction with seeds and found cooperation in bacterial colonization of seed storage tissues and growth promotion. Combining confocal microscopy with fluorogenic probes, we found that two specific components of the extracellular matrix, amyloid protein TasA and fengycin, differentially increased the concentrations of reactive oxygen species inside seeds. Further, using electron and fluorescence microscopy and metabolomics, we showed that both TasA and fengycin targeted the oil bodies in the seed endosperm, resulting in specific changes in lipid metabolism and accumulation of glutathione-related molecules. In turn, this results in two different plant growth developmental programmes: TasA and fengycin stimulate the development of radicles, and fengycin alone stimulate the growth of adult plants and resistance in the phylloplane to the fungus Botrytis cinerea. Understanding mechanisms of bacterial growth promotion will enable the design of bespoke growth promotion strains.}, } @article {pmid35666375, year = {2022}, author = {Lima, NG and Monteiro, RM and Torres, CP and de Souza-Gabriel, AE and Watanabe, E and Borsatto, MC}, title = {Influence of antimicrobial photodynamic therapy with different pre-irradiation times on children's dental biofilm: randomized clinical trial.}, journal = {European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry}, volume = {23}, number = {6}, pages = {897-904}, pmid = {35666375}, issn = {1996-9805}, mesh = {Child ; Humans ; Methylene Blue/therapeutic use ; *Photochemotherapy/methods ; Biofilms/radiation effects ; Photosensitizing Agents/therapeutic use ; *Anti-Infective Agents ; }, abstract = {PURPOSE: Photodynamic therapy (PDT) is effective in reducing pathogenic microorganisms in the oral cavity and in preventing dental diseases. This study evaluated the pre-irradiation time using PDT (diode laser associated with 0.01% methylene blue) to decrease the number of microorganisms in the visible plaque in permanent teeth.

METHODS: This randomized clinical trial included 108 homologous lower permanent first molars (36 and 46) with biofilm from 54 children aged six to 12 years. PDT was performed (0.01% methylene blue photosensitizer/therapeutic laser-InGaAIP), according to the following protocols: Group 1, biofilm collection of the distal area of the lingual surface of 36 µm before PDT; group 2, mesial area of the lingual surface of 36 µm 1 min after PDT; group 3, area of the lingual surface of 46 µm before PDT; and group 4, mesial area of the lingual surface of 46 µm 5 min after PDT.

RESULTS: After statistical analysis, significant differences were observed between the groups (p = 0.000). In groups 2 and 4, the number of bacteria tended to decrease, with a more evident bacterial reduction in group 4.

CONCLUSIONS: Pre-irradiation reduced the number of colony-forming units of mature bacterial biofilms in vivo. A time of 5 min resulted in a greater reduction in the number of colony-forming units.

CLINICAL TRIAL REGISTRATION: ReBEC Identifier: RBR-6bqfp3; Date of Register: March 2nd, 2020. Retrospectively Registered.}, } @article {pmid35663481, year = {2022}, author = {Frühauf, HM and Stöckl, M and Holtmann, D}, title = {R-based method for quantitative analysis of biofilm thickness by using confocal laser scanning microscopy.}, journal = {Engineering in life sciences}, volume = {22}, number = {6}, pages = {464-470}, pmid = {35663481}, issn = {1618-0240}, abstract = {Microscopy is mostly the method of choice to analyse biofilms. Due to the high local heterogeneity of biofilms, single and punctual analyses only give an incomplete insight into the local distribution of biofilms. In order to retrieve statistically significant results a quantitative method for biofilm thickness measurements was developed based on confocal laser scanning microscopy and the programming language R. The R-script allows the analysis of large image volumes with little hands-on work and outputs statistical information on homogeneity of surface coverage and overall biofilm thickness. The applicability of the script was shown in microbial fuel cell experiments. It was found that Geobacter sulfurreducens responds differently to poised anodes of different material so that the optimum potential for MFC on poised ITO anodes had to be identified with respect to maximum current density, biofilm thickness and MFC start-up time. Thereby, a positive correlation between current density and biofilm thickness was found, but with no direct link to the applied potential. The optimum potential turned out to be +0.1 V versus SHE. The script proved to be a valuable stand-alone tool to quantify biofilm thickness in a statistically valid manner, which is required in many studies.}, } @article {pmid35662380, year = {2022}, author = {Li, J and McLaughlin, RW and Liu, Y and Zhou, J and Hu, X and Wan, X and Xie, H and Hao, Y and Zheng, J}, title = {Biofilm formation, antimicrobial assay, and toxin-genotypes of Clostridium perfringens type C isolates cultured from a neonatal Yangtze finless porpoise.}, journal = {Archives of microbiology}, volume = {204}, number = {7}, pages = {361}, pmid = {35662380}, issn = {1432-072X}, support = {31870372//National Natural Science Foundation of China/ ; ZSSD-004//the Bureau of Science & Technology for Development, Chinese Academy of Sciences/ ; 2020M682530//Postdoctoral Research Foundation of China/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria/genetics ; Biofilms ; Clostridium perfringens/genetics ; Erythromycin ; Genotype ; *Porpoises/genetics/microbiology ; RNA, Ribosomal, 16S/genetics ; }, abstract = {This is a culture-dependent study with the objective of pure culturing and characterizing pathogenic bacteria from the blowhole, lung, stomach and fecal samples of a neonatal crucially endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) that died 27 days after birth. Bacteria were inoculated using a swab onto blood and MacConkey agar plates and representative isolates were identified through 16S rRNA gene sequence analysis. A total of three Clostridium perfringens type C strains from the fecal samples were isolated. Toxin genes, including cpa, cpb and cpb2, were detected by PCR amplification, whereas the etx, iap and cpe genes were not detected. Biofilm formation of the three strains was then examined. Only one strain was capable of biofilm formation. In addition, isolates showed strong resistance against the antibiotics amikacin (3/3), erythromycin (1/3), gentamicin (3/3), streptomycin (3/3), and trimethoprim (3/3), while sensitivity to ampicillin (3/3), bacitracin (3/3), erythromycin (2/3), penicillin G (3/3), and tetracycline (3/3). The results suggested C. perfringens type C could have contributed to the death of this neonatal porpoise.}, } @article {pmid35661475, year = {2023}, author = {Freitas, RFCP and Duarte, S and Feitosa, S and Dutra, V and Lin, WS and Panariello, BHD and Carreiro, ADFP}, title = {Physical, Mechanical, and Anti-Biofilm Formation Properties of CAD-CAM Milled or 3D Printed Denture Base Resins: In Vitro Analysis.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {32}, number = {S1}, pages = {38-44}, doi = {10.1111/jopr.13554}, pmid = {35661475}, issn = {1532-849X}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 433178/2018-3//National Council for Scientific and Technological Development (CNPq)/ ; }, mesh = {*Polymethyl Methacrylate ; Materials Testing ; *Denture Bases ; Surface Properties ; Computer-Aided Design ; Printing, Three-Dimensional ; }, abstract = {PURPOSE: To investigate surface characteristics (roughness and contact angle), anti-biofilm formation, and mechanical properties (mini-flexural strength) of computer-aided design and computer-aided manufacturing (CAD-CAM) polymethylmethacrylate (PMMA) polymer, and three-dimensional (3D) printed resin for denture base fabrication compared with conventional heat polymerized denture base resins.

MATERIALS AND METHODS: A total of 60 discs and 40 rectangular specimens were fabricated from one CAD-CAM (AvaDent), one 3D printed (Cosmos Denture), and two conventional heat polymerized (Lucitone 199 and VipiWave) materials for denture base fabrication. Roughness was determined by Ra value; the contact angle was measured by the sessile drop method. The biofilm formation inhibition behavior was analyzed through Candida albicans adhesion, while mini-flexural strength test was done using a three-point bending test. The data were analyzed using descriptive and analytical statistics (α = 0.05).

RESULTS: The CAD-CAM PMMA group showed the lowest C. albicans adhesion (log CFU/mL: 3.74 ± 0.57) and highest mini-flexural strength mean (114.96 ± 16.23 MPa). 3D printed specimens presented the highest surface roughness (Ra: 0.317 ± 0.151 μm) and lowest mini-flexural strength values (57.23 ± 9.07 MPa). However, there was no statistical difference between CAD-CAM PMMA and conventional groups for roughness, contact angle, and mini-flexural strength.

CONCLUSIONS: CAD-CAM milled materials present surface and mechanical properties similar to conventional resins and show improved behavior in preventing C. albicans adhesion. Nevertheless, 3D printed resins present decreased mini-flexural strength.}, } @article {pmid35661216, year = {2022}, author = {Priya, A and Pandian, SK}, title = {Biofilm and hyphal inhibitory synergistic effects of phytoactives piperine and cinnamaldehyde against Candida albicans.}, journal = {Medical mycology}, volume = {60}, number = {8}, pages = {}, doi = {10.1093/mmy/myac039}, pmid = {35661216}, issn = {1460-2709}, mesh = {Acrolein/analogs & derivatives ; Alkaloids ; Animals ; Antifungal Agents/pharmacology ; Benzodioxoles ; Biofilms ; *Candida albicans ; *Candidiasis, Oral/veterinary ; Humans ; Microbial Sensitivity Tests/veterinary ; Piperidines ; Polyunsaturated Alkamides ; }, abstract = {Oral candidiasis, the most common mycotic infection of the human oral cavity is non-life-threatening yet, if untreated, may advance as systemic infections. The ability of Candida albicans to adapt sessile lifestyle imparts resistance to drugs and host immunity. Consequently, due to the limited effectiveness of conventional antifungal treatment, novel therapeutic strategies are required. In the present study, synergistic interaction of phytochemicals, piperine, and cinnamaldehyde against the biofilm and hyphal of C. albicans was evaluated. Minimum inhibitory concentration (MIC) and biofilm inhibitory concentration (BIC) of piperine and cinnamaldehyde against C. albicans were analyzed through microbroth dilution assay and crystal violet staining method, respectively. Combinatorial biofilm and hyphal inhibitory effect were investigated through checkerboard assay. In vitro results were validated through gene expression analysis. BIC of piperine and cinnamaldehyde was determined to be 32 μg/ml and 64 μg/ml, respectively. Interaction between these two phytocomponents was found to be synergistic and six different synergistic antibiofilm combinations were identified. Microscopic analysis of biofilm architecture also evidenced the biofilm and surface adherence inhibitory potential of piperine and cinnamaldehyde combinations. Phenotypic switching between yeast and hyphal morphological forms was influenced by synergistic combinations. qPCR analysis corroborated the results of in vitro activities. nrg1 and trp1, the negative transcriptional regulators of filamentous growth were upregulated whereas other genes that are involved in biofilm formation, filamentous growth, adhesion, etc. were found to be downregulated. These proficient phytochemical combinations provide a new therapeutic avenue for the treatment of biofilm-associated oral candidiasis and to combat the recurrent infections due to antibiotic resistance.}, } @article {pmid35660567, year = {2022}, author = {Lian, S and Qu, Y and Dai, C and Li, S and Jing, J and Sun, L and Yang, Y}, title = {Succession of function, assembly, and interaction of microbial community in sequencing biofilm batch reactors under selenite stress.}, journal = {Environmental research}, volume = {212}, number = {Pt E}, pages = {113605}, doi = {10.1016/j.envres.2022.113605}, pmid = {35660567}, issn = {1096-0953}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; Selenious Acid ; *Selenium ; Wastewater ; }, abstract = {The mechanism of interaction between selenite, a toxic substance, and the microbial community in wastewater is still not well understood. Herein, nine sequencing biofilm batch reactors were used to systematically investigate the response of the microbial community to the continuous selenite stress. The results showed that selenite affected the reactor performance and reduced the biofilm mass. Also, it increased the proportion of the living cells, and changed the protein and polysaccharide composition of the biofilm as well as cellular secretions. Selenite facilitated the removal of NO3-N, according to water-quality and bioinformatics analyses. As such, the selenite was converted into selenium nanoparticles. α-diversity analysis further revealed that 20 μM selenite enhanced the microbial community resilience, while 200 μM selenite had the reverse effect. Community composition analysis showed that Variovorax, Rhizobium, and Simkania had positive correlations with selenite (P < 0.05). Functional prediction suggested that selenite changed the C, N, and S cycle functions. Furthermore, determinism dominated the community assembly process, and the deterministic proportion increased with the increase of selenite concentration. Network analysis showed that selenite improved the stability and positive correlation ratio of the overall microbial network, and accelerated the communication between microorganisms. However, when compared with the 20 μM selenite, the 200 μM selenite boosted the competition and parasitism/predation among microorganisms. Low-abundance genera played a key role in the network of selenite-reducing microbial community. In addition, under selenite stress, biofilm network exhibited better stability and faster information exchange than suspended network, and the positive association between biofilm and suspended microorganisms increased. All in all, this research sheds light on the interaction between selenite and microbial community, as well as provides crucial information on selenium-containing wastewater.}, } @article {pmid35660455, year = {2022}, author = {Luan, YN and Yin, Y and An, Y and Zhang, F and Wang, X and Zhao, F and Xiao, Y and Liu, C}, title = {Investigation of an intermittently-aerated moving bed biofilm reactor in rural wastewater treatment under low dissolved oxygen and C/N condition.}, journal = {Bioresource technology}, volume = {358}, number = {}, pages = {127405}, doi = {10.1016/j.biortech.2022.127405}, pmid = {35660455}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Denitrification ; Nitrification ; Nitrogen ; Oxygen ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {An intermittently-aerated moving bed biofilm reactor (MBBR) was proposed for nitrogen and carbon removal from low C/N synthetic rural wastewater. In purposes of low energy consumption and costs, the intermittent aeration modes were changed and the dissolved oxygen was reduced gradually during the operation. The results showed that effluent concentrations of ammonia nitrogen and chemical oxygen demand were lower than 15 and 50 mg/L, respectively, even under microaerobic condition (0.1-1.0 mg/L). Meanwhile, the simultaneous nitrification-denitrification was achieved by intermittent aeration. The activity of functional bacteria was still high and the proportion of autotrophic biomass increased significantly under intermittent micro-aeration mode, which improved the nitrification performance. Aerobic denitrifier Hydrogenophaga, anoxic denitrifier Thiothrix, and heterotrophic nitrifier such as Rhodobacter were enriched in the intermittently micro-aerated MBBR, which will provide an applicable solution for rural wastewater treatment under low C/N and costs.}, } @article {pmid35659363, year = {2022}, author = {Brunke, MS and Konrat, K and Schaudinn, C and Piening, B and Pfeifer, Y and Becker, L and Schwebke, I and Arvand, M}, title = {Tolerance of biofilm of a carbapenem-resistant Klebsiella pneumoniae involved in a duodenoscopy-associated outbreak to the disinfectant used in reprocessing.}, journal = {Antimicrobial resistance and infection control}, volume = {11}, number = {1}, pages = {81}, pmid = {35659363}, issn = {2047-2994}, mesh = {Bacteria ; Biofilms ; *Carbapenem-Resistant Enterobacteriaceae ; Carbapenems/pharmacology ; *Cross Infection/epidemiology/prevention & control ; Disease Outbreaks ; *Disinfectants/pharmacology ; Duodenoscopy ; Humans ; Klebsiella pneumoniae ; Peracetic Acid/pharmacology ; }, abstract = {BACKGROUND: One possible transmission route for nosocomial pathogens is contaminated medical devices. Formation of biofilms can exacerbate the problem. We report on a carbapenemase-producing Klebsiella pneumoniae that had caused an outbreak linked to contaminated duodenoscopes. To determine whether increased tolerance to disinfectants may have contributed to the outbreak, we investigated the susceptibility of the outbreak strain to disinfectants commonly used for duodenoscope reprocessing. Disinfection efficacy was tested on planktonic bacteria and on biofilm.

METHODS: Disinfectant efficacy testing was performed for planktonic bacteria according to EN standards 13727 and 14561 and for biofilm using the Bead Assay for Biofilms. Disinfection was defined as ≥ 5log10 reduction in recoverable colony forming units (CFU).

RESULTS: The outbreak strain was an OXA-48 carbapenemase-producing K. pneumoniae of sequence type 101. We found a slightly increased tolerance of the outbreak strain in planktonic form to peracetic acid (PAA), but not to other disinfectants tested. Since PAA was the disinfectant used for duodenoscope reprocessing, we investigated the effect of PAA on biofilm of the outbreak strain. Remarkably, disinfection of biofilm of the outbreak strain could not be achieved by the standard PAA concentration used for duodenoscope reprocessing at the time of outbreak. An increased tolerance to PAA was not observed in a K. pneumoniae type strain tested in parallel.

CONCLUSIONS: Biofilm of the K. pneumoniae outbreak strain was tolerant to standard disinfection during duodenoscope reprocessing. This study establishes for the first time a direct link between biofilm formation, increased tolerance to disinfectants, reprocessing failure of duodenoscopes and nosocomial transmission of carbapenem-resistant K. pneumoniae.}, } @article {pmid35658710, year = {2022}, author = {Goodyear, MC and Garnier, NE and Levesque, RC and Khursigara, CM}, title = {Liverpool Epidemic Strain Isolates of Pseudomonas aeruginosa Display High Levels of Antimicrobial Resistance during Both Planktonic and Biofilm Growth.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0102422}, pmid = {35658710}, issn = {2165-0497}, support = {PJT 156111//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Plankton ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; }, abstract = {Eight isolates of the Liverpool epidemic strain (LES) of Pseudomonas aeruginosa have previously been characterized using comparative genomics and preliminary phenotypic assays. Here, we extend the characterization of these clinically relevant P. aeruginosa isolates with planktonic and biofilm growth assays and analysis of antibiotic susceptibility for both planktonic and biofilm cultures. Laboratory strains PAO1 and PA14 were included as comparator strains. Antibiotic susceptibility to eight classes of antibiotics was determined. MICs were determined to measure susceptibility of planktonic cultures, and minimum biofilm eradication concentration (MBEC) assays were used to estimate levels of resistance during the production of biofilm. LES isolates had high levels of resistance compared with laboratory reference strains when grown planktonically (up to nine 2-fold dilutions higher), and resistance was increased in the biofilm mode of growth. Measurements of biofilm biomass in the MBEC assays showed that certain isolates often show increased biofilm biomass in the presence of antibiotics. IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogen with high intrinsic antibiotic resistance. This resistance is typically increased in clinical isolates through adaptations to the host and production of small-colony variants (SCVs) and when P. aeruginosa forms biofilms, which are surface-attached communities that are protected by a self-produced matrix. Understanding the combination of SCVs, biofilm production, and the diversity of drug resistance phenotypes in clinical isolates can lead to improved treatments for P. aeruginosa infections.}, } @article {pmid35656684, year = {2021}, author = {Arora, SS and Shetty, R and Hemagiriyappa, MS and Thakur, SS and Mishra, N and Lokhande, NM}, title = {Comparative Evaluation of Antibacterial Efficacy of Silver and Cadmium Nanoparticles and Calcium Hydroxide against Enterococcus faecalis Biofilm.}, journal = {The journal of contemporary dental practice}, volume = {22}, number = {12}, pages = {1438-1443}, pmid = {35656684}, issn = {1526-3711}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms/drug effects ; *Cadmium/pharmacology ; *Calcium Hydroxide/pharmacology ; *Enterococcus faecalis/drug effects ; Gels ; *Metal Nanoparticles ; Root Canal Irrigants/pharmacology ; *Silver/pharmacology ; }, abstract = {AIM: The purpose of this study was to evaluate and compare the antibacterial efficacy of calcium hydroxide medicament, silver (AgNPs) and cadmium nanoparticles (CdSNPs) as medicament against the biofilms of Enterococcus faecalis on dentin sections. E. faecalis is commonly detected in asymptomatic and persistent endodontic infections.

METHODS: Twenty standard size dentin sections were prepared. E. faecalis was inoculated on these dentin sections for four weeks to form the bacterial biofilm. Twenty dentin sections were segregated into four different groups with five specimens in each group. Group I was kept as control group, and antibacterial efficacy was tested by treating biofilms with Ca(OH) 2 medicament, 0.02% AgNP and CdSNP gels for 7 days. The ultrastructure of biofilms from each group was examined under scanning electron microscope and was visually evaluated and compared for different groups.

RESULTS: Ca(OH)2 exhibited a slight disruption of E. faecalis biofilm. Both AgNP and CdSNP medicaments disrupted E. faecalis biofilm effectively after 7 days of inoculation. AgNPs disrupted the biofilm more effectively than CdSNPs. Biofilms in control group, which was irrigated with saline, did not show any disruption of biofilm, which could be seen as homogenous layer over most of dentin sections.

CONCLUSIONS: This study suggests that both AgNP and CdNP gels are effective against E. faecalis and can be used as a medicament to eliminate residual bacterial biofilms during root canal disinfection. AgNP medicament is more effective than CdNP, whereas Ca(OH) 2 is not effective against E. faecalis biofilms.

CLINICAL SIGNIFICANCE: Incomplete clearance and the development of antibiotic resistance in E. faecalis are the important factors for failure of root canal treatment. When cationic nanoparticles are introduced for the treatment of biofilms, it can interact with both extracellular polymeric substances and bacterial cells. The initial electrostatic attraction between positively charged nanoparticles and negatively charged bacterial surface leads to bacterial killing via the production of reactive oxygen species. Metal nanoparticles that are effective against E. faecalis have a significant potential role in the prevention and treatment of such cases, as bacteria do not develop resistance against metal nanoparticles.}, } @article {pmid35655484, year = {2022}, author = {Rajabi, H and Salimizand, H and Khodabandehloo, M and Fayyazi, A and Ramazanzadeh, R}, title = {Prevalence of algD, pslD, pelF, Ppgl, and PAPI-1 Genes Involved in Biofilm Formation in Clinical Pseudomonas aeruginosa Strains.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {1716087}, pmid = {35655484}, issn = {2314-6141}, mesh = {Biofilms ; Cross-Sectional Studies ; Humans ; Prevalence ; *Pseudomonas Infections/drug therapy/epidemiology/genetics ; *Pseudomonas aeruginosa ; }, abstract = {INTRODUCTION: Biofilm formation is one of the main virulence factors in Pseudomonas aeruginosa infections. This study is aimed at investigating the presence of genes involved in biofilm formation in clinical P. aeruginosa isolates. Material and Methods. A cross-sectional study was conducted on 112 P. aeruginosa isolates. The biofilm formation assay was performed on all isolates. Antimicrobial resistance was determined by the disk diffusion method, and the presence of genes was detected by polymerase chain reaction. Isolates were typed with Rep-PCR.

RESULTS: The results of biofilm formation demonstrated that 85 strains (75.9%) were biofilm producers, and 27 strains (24.1%) were nonproducer isolates. Antibiotic susceptibility pattern in biofilm-positive and biofilm-negative isolates obtained from hospitalized patients showed a high rate of antibiotic resistance to amoxicillin with 95.7% and 92.3%, respectively. Based on PCR amplification results, the frequency of genes involved in biofilm formation among all isolates was as follows: algD (78.6%), pelF (70.5%), pslD (36.6%), Ppgl (0%), and PAPI-1 (77.6%). Rep-PCR typing demonstrated that 112 P. aeruginosa isolates were classified into 57 types according to 70% cut-off. The predominant type was A which contained 15 isolates. Moreover, 7 isolates were clustered in genotype B, followed by C type (6), D (4), E (4), F (4), G (4), H (3), I (3), J (3 isolates), and 12 genotypes, each containing two isolates. Also, 35 isolates were distributed in scattered patterns and showed single types.

CONCLUSION: Study results showed significant association between biofilm formation and resistance to antibiotics such as ceftazidime and meropenem. Analysis of Rep-PCR patterns indicated that the evaluated isolates were heterogeneous, relatively.}, } @article {pmid35655421, year = {2022}, author = {Fiallos, NM and Aguiar, ALR and Nascimento da Silva, B and Rocha, MFG and Sidrim, JJC and Castelo Branco de Souza Collares Maia, D and Cordeiro, RA}, title = {Enterococcus faecalis and Candida albicans dual-species biofilm: establishment of an in vitro protocol and characterization.}, journal = {Biofouling}, volume = {38}, number = {4}, pages = {401-413}, doi = {10.1080/08927014.2022.2084612}, pmid = {35655421}, issn = {1029-2454}, mesh = {*Anti-Infective Agents ; Biofilms ; Candida albicans ; *Enterococcus faecalis ; }, abstract = {Enterococcus faecalis is the most important agent of persistent apical periodontitis, and recently, Candida albicans has also been implicated in periapical infections. This study aimed to optimize an in vitro E. faecalis and C. albicans dual-species biofilm protocol for endodontic research. Different physicochemical conditions for biofilm formation were tested. Susceptibility assays to antimicrobials, biochemical composition and an ultra-morphological structure analyses were performed. Reproducible dual-species biofilms were established in BHI medium at 35 °C, for 48 h and in a microaerophilic atmosphere. An increase in biomass and chitin content was detected after vancomycin treatment. Structural analysis revealed that the dual-species biofilm was formed by both microorganisms adhered to the substrate. The proposed protocol could be useful for the study of interkingdom relationships and help to find new strategies against periapical infections.}, } @article {pmid35655342, year = {2022}, author = {Ma, LZ and Wang, D and Liu, Y and Zhang, Z and Wozniak, DJ}, title = {Regulation of Biofilm Exopolysaccharide Biosynthesis and Degradation in Pseudomonas aeruginosa.}, journal = {Annual review of microbiology}, volume = {76}, number = {}, pages = {413-433}, doi = {10.1146/annurev-micro-041320-111355}, pmid = {35655342}, issn = {1545-3251}, mesh = {Biofilms ; Humans ; *Polysaccharides, Bacterial ; *Pseudomonas aeruginosa/metabolism ; }, abstract = {Microbial communities enmeshed in a matrix of macromolecules, termed as biofilms, are the natural setting of bacteria. Exopolysaccharide is a critical matrix component of biofilms. Here, we focus on biofilm matrix exopolysaccharides in Pseudomonas aeruginosa. This opportunistic pathogen can adapt to a wide range of environments and can form biofilms or aggregates in a variety of surfaces or environments, such as the lungs of people with cystic fibrosis, catheters, wounds, and contact lenses. The ability to synthesize multiple exopolysaccharides is one of the advantages that facilitate bacterial survival in different environments. P. aeruginosa can produce several exopolysaccharides, including alginate, Psl, Pel, and lipopolysaccharide. In this review, we highlight the roles of each exopolysaccharide in P. aeruginosa biofilm development and how bacteria coordinate the biosynthesis of multiple exopolysaccharides and bacterial motility. In addition, we present advances in antibiofilm strategies targeting matrix exopolysaccharides, with a focus on glycoside hydrolases.}, } @article {pmid35655210, year = {2022}, author = {Azara, E and Longheu, CM and Attene, S and Sanna, S and Sale, M and Addis, MF and Tola, S}, title = {Comparative profiling of agr locus, virulence, and biofilm-production genes of human and ovine non-aureus staphylococci.}, journal = {BMC veterinary research}, volume = {18}, number = {1}, pages = {212}, pmid = {35655210}, issn = {1746-6148}, mesh = {Adhesins, Bacterial/genetics ; Animals ; *Biofilms ; Enterotoxins ; Female ; Humans ; Sheep ; *Staphylococcus/genetics ; Virulence/genetics ; }, abstract = {BACKGROUND: In a collaboration between animal and human health care professionals, we assessed the genetic characteristics shared by non-aureus staphylococci (NAS) infecting humans and dairy ewes to investigate their relatedness in a region concentrating half of the total National sheep stock. We examined by PCR 125 ovine and 70 human NAS for biofilm production, pyrogenic toxins, adhesins, autolysins genes, and accessory gene regulator (agr) locus. The microtiter plate assay (MPA) was used for the phenotypic screening of biofilm production. Ovine NAS included S. epidermidis, S. chromogenes, S. haemolyticus, S. simulans, S. caprae, S. warneri, S. saprophyticus, S. intermedius, and S. muscae. Human NAS included S. haemolyticus, S. epidermidis, S. hominis, S. lugdunensis, S. capitis, S. warneri, S. xylosus, S. pasteuri, and S. saprophyticus subsp. bovis.

RESULTS: Phenotypically, 41 (32.8%) ovine and 24 (34.3%) human isolates were characterized as biofilm producers. Of the ovine isolates, 12 were classified as biofilm-producing while the remaining 29 as weak biofilm-producing. All 24 human isolates were considered weak biofilm-producing. Few S. epidermidis isolates harbored the icaA/D genes coding for the polysaccharide intercellular adhesin (PIA), while the bhp, aap, and embp genes coding biofilm accumulation proteins were present in both non-producing and biofilm-producing isolates. Fifty-nine sheep NAS (all S. epidermidis, 1 S. chromogenes, and 1 S. haemolyticus) and 27 human NAS (all S. epidermidis and 1 S. warneri) were positive for the agr locus: agr-3se (57.8%) followed by agr-1se (36.8%) predominated in sheep, while agr-1se (65.4%), followed by agr-2se (34.6%) predominated in humans. Concerning virulence genes, 40, 39.2, 47.2%, 52.8, 80 and 43.2% of the sheep isolates carried atlE, aae, sdrF, sdrG, eno and epbS respectively, against 37.1, 42.8, 32.8, 60, 100 and 100% of human isolates. Enterotoxins and tsst were not detected.

CONCLUSIONS: Considerable variation in biofilm formation ability was observed among NAS isolates from ovine and human samples. S. epidermidis was the best biofilm producer with the highest prevalence of adhesin-encoding genes.}, } @article {pmid35655208, year = {2022}, author = {Przekwas, J and Gębalski, J and Kwiecińska-Piróg, J and Wiktorczyk-Kapischke, N and Wałecka-Zacharska, E and Gospodarek-Komkowska, E and Rutkowska, D and Skowron, K}, title = {The effect of fluoroquinolones and antioxidans on biofilm formation by Proteus mirabilis strains.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {21}, number = {1}, pages = {22}, pmid = {35655208}, issn = {1476-0711}, mesh = {Anti-Bacterial Agents/pharmacology ; Ascorbic Acid/pharmacology ; Biofilms ; Ciprofloxacin/pharmacology ; *Fluoroquinolones/pharmacology ; Humans ; Norfloxacin ; *Proteus mirabilis ; Rutin ; }, abstract = {BACKGROUND: Fluoroquinolones are a group of antibiotics used in urinary tract infections. Unfortunately, resistance to this group of drugs is currently growing. The combined action of fluoroquinolones and other antibacterial and anti-biofilm substances may extend the use of this therapeutic option by clinicians. The aim of the study was to determine the effect of selected fluoroquinolones and therapeutic concentrations of ascorbic acid and rutoside on biofilm formation by Proteus mirabilis.

MATERIALS AND METHODS: The study included 15 strains of P. mirabilis isolated from urinary tract infections in patients of the University Hospital No. 1 dr A. Jurasz in Bydgoszcz (Poland). The metabolic activity of the biofilm treated with 0.4 mg/ml ascorbic acid, 0.02 µg/ml rutoside and chemotherapeutic agents (ciprofloxacin, norfloxacin) in the concentration range of 0.125-4.0 MIC (minimum inhibitory concentration) was assessed spectrophotometrically.

RESULTS: Both ciprofloxacin and norfloxacin inhibited biofilm formation by the tested strains. The biofilm reduction rate was correlated with the increasing concentration of antibiotic used. No synergism in fluoroquinolones with ascorbic acid, rutoside or both was found. The ascorbic acid and rutoside combination, however, significantly decreased biofilm production.

CONCLUSIONS: Our research proves a beneficial impact of ascorbic acid with rutoside supplementation on biofilm of P. mirabilis strains causing urinary tract infections.}, } @article {pmid35653845, year = {2022}, author = {Carneiro, RB and Gomes, GM and Zaiat, M and Santos-Neto, ÁJ}, title = {Two-phase (acidogenic-methanogenic) anaerobic fixed bed biofilm reactor enhances the biological domestic sewage treatment: Perspectives for recovering bioenergy and value-added by-products.}, journal = {Journal of environmental management}, volume = {317}, number = {}, pages = {115388}, doi = {10.1016/j.jenvman.2022.115388}, pmid = {35653845}, issn = {1095-8630}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; *Euryarchaeota ; Methane ; *Sewage/microbiology ; }, abstract = {The organic matter bioconversion into methane during anaerobic digestion (AD) comprises different steps, the acidogenic and methanogenic phases being clearly distinct in terms of metabolic activities. In this work, new configurations of anaerobic fixed bed biofilm reactors (AFBBR) were operated under conventional methanogenic conditions (single phase - SP-AFBBR, M1R), and in a sequential two-phase system, acidogenic reactor followed by methanogenic reactor (TP-AFBBR, AcR + M2R), in order to verify the impact of the AD phase separation on the overall system performance in operational, kinetics and microbiological aspects. The results indicated that feeding the methanogenic reactor with the acidogenic effluent stream provided a shorter operating start-up period (11 and 32 days for SP and TP-AFBBR, respectively), a greater alkalinity generation (0.14 and 0.41 g-CaCO3·g-CODremoved[-1] for M1R and M2R, respectively), and the optimization of biomethane production (methane yield of 95 and 154 N-mLCH4·g-CODremoved[-1] for M1R and M2R, respectively). The COD removal kinetics was also favored in the TP-AFBBR (k1-COD = 1.4 and 2.9 h[-1] for M1R and M2R, respectively), since the soluble fermentation products were readily bioavailable to the biomass in the reactor. Hydrogenotrophic methanogenesis was the predominant pathway in the M2R, while the Methanosaeta-driven acetoclastic pathway predominated in the M1R. The greater diversity of Bacteria and Archaea in M2R denotes a better balance between the species that degrade volatile organic acids from AcR (i.e. Syntrophorhabdus, Syntrophus and Syntrophobacter) and the hydrogenotrophic methanogens (Methanoregula, Methanolinea and Methanospirillum) that consume the biodegradation products. The estimated bioenergy generation potential (range of 0.39-0.64 kWh·m[-3]-sewage considering the COD removed) for full-scale TP-sewage treatment plants evidences the feasibility of energetic recovery in the domestic sewage anaerobic treatment.}, } @article {pmid35651751, year = {2022}, author = {Woitschach, F and Kloss, M and Schlodder, K and Borck, A and Grabow, N and Reisinger, EC and Sombetzki, M}, title = {Bacterial Adhesion and Biofilm Formation of Enterococcus faecalis on Zwitterionic Methylmethacrylat and Polysulfones.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {868338}, pmid = {35651751}, issn = {2235-2988}, mesh = {Bacteria ; *Bacterial Adhesion ; Biofilms ; *Enterococcus faecalis ; Humans ; Polymers ; Sulfones/metabolism ; }, abstract = {Biofilm-associated implant infections represent a major challenge for healthcare systems around the world due to high patient burden and enormous costs incurred. Enterococcus faecalis (E. faecalis) is the most prevalent enterococcal species identified in biofilm-associated infections. The steadily growing areas of application of implants demand a solution for the control of bacterial infections. Therefore, the development of modified anti-microbial implant materials and the testing of the behavior of different relevant bacterial strains towards them display an indispensable task. Recently, we demonstrated an anti-microbial effect of zwitterionic modified silicone rubber (LSR) against Staphylococcus aureus. The aim of this study was to evaluate bacterial colonization and biofilm formation of another clinically relevant strain, E. faecalis, on this material in comparison to two of the most commonly used thermoplastic polyurethanes (TPUs) and other modified LSR surfaces. By generating growth curves, crystal violet, and fluorescence staining, as well as analyzing the expression of biofilm-associated genes, we demonstrated no anti-microbial activity of the investigated materials against E. faecalis. These results point to the fact that anti-microbial effects of novel implant materials do not always apply across the board to all bacterial strains.}, } @article {pmid35651015, year = {2022}, author = {Wang, Y and Sun, L and Hu, L and Wang, Z and Wang, X and Dong, Q}, title = {Adhesion and kinetics of biofilm formation and related gene expression of Listeria monocytogenes in response to nutritional stress.}, journal = {Food research international (Ottawa, Ont.)}, volume = {156}, number = {}, pages = {111143}, doi = {10.1016/j.foodres.2022.111143}, pmid = {35651015}, issn = {1873-7145}, mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; Food Microbiology ; Gene Expression ; Kinetics ; *Listeria monocytogenes/genetics ; }, abstract = {Listeria monocytogenes is a gram-positive pathogen, that usually adheres to stainless steel (SS), and other abiotic surfaces in food processing that undergo repeated cleaning and cause the spread of Listeria. Through the enumeration of biofilm cells, extracellular polymeric substance (EPS) component and the scanning electron microscopy (SEM) analysis of biofilms, it was found that the ratio of cells and extracellular matrix is affected by nutrition status. Regardless of the temperature, all strains exhibited a higher adhesion ability when exposed to 10-fold diluted TSB-YE (DTSB-YE, nutrition deficiency). Three hour initial adhesion was significantly positively correlated with biofilm formation (p＜0.01). DTSB-YE enhances initial attachment and subsequently promotes biofilm formation. The SEM analysis also showed that in DTSB-YE the adhesion and covered area of the attached cells were higher than those in TSB-YE (rich media). The amount of both extracellular polysaccharides and proteins was significantly higher when incubated in DTSB-YE than TSB-YE. The highest biofilm formation of Lm83 was observed in DTSBYE independent of temperature. The effects of nutrition deficiency on the expression of critical biofilm-associated genes of Lm 83 planktonic and biofilm cells were measured. The gene expression levels of inlA and sigB in biofilm cells in TSB-YE and DTSB-YE were approximately 95.7% and 88.0% and 42.2% and 45.7% lower than those in planktonic cells, respectively. However, the expression of inlA in DTSB-YE was significantly higher (p＜0.05) than that in TSB-YE for the same cell state. Interestingly, the gene expression of motB was considerably higher in DTSB-YE than in TSBYE, regardless of the state. These results indicate that better cell motility in nutrient deficiencies might facilitate the cell aggression to promote biofilm formation.}, } @article {pmid35650279, year = {2022}, author = {Kumar, R and Singh, N and Chauhan, A and Kumar, M and Bhatta, RS and Singh, SK}, title = {Mycobacterium tuberculosis survival and biofilm formation studies: effect of D-amino acids, D-cycloserine and its components.}, journal = {The Journal of antibiotics}, volume = {75}, number = {8}, pages = {472-479}, pmid = {35650279}, issn = {1881-1469}, support = {MLP2033//CSIR | Central Drug Research Institute (CDRI)/ ; EMR/2017/001295//DST | Science and Engineering Research Board (SERB)/ ; }, mesh = {Amino Acids/metabolism/pharmacology ; Biofilms ; Cycloserine/pharmacology ; Hydroxylamines/metabolism/pharmacology ; *Mycobacterium tuberculosis ; Peptidoglycan/metabolism ; }, abstract = {D-amino acids play an important role in cell wall peptidoglycan biosynthesis. Mycobacterium tuberculosis D-amino acid oxidase deletion led to reduced biofilm-forming ability. Other recent studies also suggest that the accumulation of D-amino acids blocks biofilm formation and could also disperse pre-formed biofilm. Biofilms are communities of bacterial cells protected by extracellular matrix and harbor drug-tolerant as well as persistent bacteria. In Mycobacterium tuberculosis, biofilm formation or its inhibition by D-amino acids is yet to be tested. In the present study, we used selected D-amino acids to study their role in the prevention of biofilm formation and also if D-cycloserine's activity was due to presence of D-Serine as a metabolite. It was observed that D-serine limits biofilm formation in Mycobacterium tuberculosis H37Ra (Mtb-Ra), but it shows no effect on pre-formed biofilm. Also, D-cycloserine and its metabolic product, hydroxylamine, individually and in combination, with D-Serine, limit biofilm formation in Mtb-Ra and also disrupts existing biofilm. In summary, we demonstrated that D-alanine, D-valine, D-phenylalanine, D-serine, and D-threonine had no disruptive effect on pre-formed biofilm of Mtb-Ra, either individually or in combination, and D-cycloserine and its metabolite hydroxylamine have potent anti-biofilm activity.}, } @article {pmid35649316, year = {2022}, author = {Forero-Doria, O and Parra-Cid, C and Venturini, W and Espinoza, C and Araya-Maturana, R and Valenzuela-Riffo, F and Saldias, C and Leiva, A and Duarte, Y and Echeverría, J and Guzmán, L}, title = {Novel N-benzoylimidazolium ionic liquids derived from benzoic and hydroxybenzoic acids as therapeutic alternative against Biofilm-forming bacteria in skin and soft-tissue infections.}, journal = {Bioorganic chemistry}, volume = {126}, number = {}, pages = {105914}, doi = {10.1016/j.bioorg.2022.105914}, pmid = {35649316}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Bacteria ; Biofilms ; Escherichia coli ; Humans ; Hydroxybenzoates/pharmacology ; *Ionic Liquids/pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; *Soft Tissue Infections ; }, abstract = {The skin and soft tissue infections (SSTIs) -producing pathogens have acquired resistance to a wide range of antimicrobials, thus it is highly relevant to have new treatment alternatives. In this study, we report the synthesis, characterization, and antibacterial activity of three novel series of ionic liquids (ILs) derived from benzoic and hydroxybenzoic acids, with different lengths of the alkyl chain. The minimum inhibitory concentration (MIC) were tested in Gram-positive: Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes, and Gram-negative: Acinetobacter baumannii and Escherichia coli, showing a MIC range of 0.01562-2.0 mM, with the activity varying according to the aromatic ring functionalization and the length of the alkyl chains. Regarding the antibiofilm activity, different efficacy was observed among the different ILs, some of them presenting antibiofilm activities close to 80% as in the case of those derived from syringic acid with an alkyl chain of six carbon atoms against Pseudomonas aeruginosa. Furthermore, the cell viability in HaCaT cells was determined, showing a half maximal effective concentration (EC50) values higher than the MIC values. The antimicrobial and antibiofilm results, along with not producing cellular toxicity at the MIC values shows that these ILs could be a promising alternative against SSTIs.}, } @article {pmid35648454, year = {2022}, author = {Qiu, M and Feng, L and Zhao, C and Gao, S and Bao, L and Zhao, Y and Fu, Y and Hu, X}, title = {Commensal Bacillus subtilis from cow milk inhibits Staphylococcus aureus biofilm formation and mastitis in mice.}, journal = {FEMS microbiology ecology}, volume = {98}, number = {7}, pages = {}, doi = {10.1093/femsec/fiac065}, pmid = {35648454}, issn = {1574-6941}, mesh = {Animals ; *Bacillus ; Bacillus subtilis ; Biofilms ; Cattle ; Female ; Humans ; *Mastitis, Bovine/microbiology/prevention & control ; Mice ; Milk/microbiology ; *Staphylococcal Infections/microbiology/prevention & control ; Staphylococcus aureus ; }, abstract = {The colonization and virulence production of Staphylococcus aureus (S. aureus), a known pathogen that induces mastitis, depend on its quorum-sensing (QS) system and biofilm formation. It has been reported that Bacillus can inhibit the QS system of S. aureus, thereby reducing S. aureus colonization in the intestine. However, whether Bacillus affects S. aureus biofilm formation and consequent colonization during mastitis is still unknown. In this study, the differences in the colonization of S. aureus and Bacillus were first analyzed by isolating and culturing bacteria from milk samples. It was found that the colonization of Bacillus and S. aureus in cow mammary glands was negatively correlated. Secondly, we found that although Bacillus did not affect S. aureus growth, it inhibited the biofilm formation of S. aureus by interfering its QS signaling. The most significant anti-biofilm effect was found in Bacillus subtilis H28 (B. subtilis H28). Finally, we found that B. subtilis H28 treatment alleviated S. aureus-induced mastitis in a mice model. Our results rerealed that bovine milk derived commensal Bacillus inhibited S. aureus colonization and alleviated S. aureus-induced mastitis by influencing biofilm formation, suggesting a potential targeted strategy to limit the colonization of S. aureus in vivo.}, } @article {pmid35648339, year = {2022}, author = {Liu, ZH and Chiang, MT and Lin, HY}, title = {Lytic Bacteriophage as a Biomaterial to Prevent Biofilm Formation and Promote Neural Growth.}, journal = {Tissue engineering and regenerative medicine}, volume = {19}, number = {5}, pages = {987-1000}, pmid = {35648339}, issn = {2212-5469}, mesh = {Anti-Bacterial Agents ; *Bacteriophages ; Biocompatible Materials ; Biofilms ; *Chitosan ; Glutaral ; }, abstract = {BACKGROUND: Although non-lytic filamentous bacteriophages have been made into biomaterial to guide tissue growth, they had limited ability to prevent bacterial infection. In this work a lytic bacteriophage was used to make an antibacterial biomaterial for neural tissue repair.

METHODS: Lytic phages were chemically bound to the surface of a chitosan film through glutaraldehyde crosslinking. After the chemical reaction, the contact angle of the sample surface and the remaining lytic potential of the phages were measured. The numbers of bacteria on the samples were measured and examined under scanning electron microscopy. Transmission electron microscopy (TEM) was used to observe the phages and phage-infected bacteria. A neuroblast cell line was cultured on the samples to evaluate the sample's biocompatibility.

RESULTS: The phages conjugated to the chitosan film preserved their lytic potential and reduced 68% of bacterial growth on the sample surface at 120 min (p < 0.001). The phage-linked surface had a significantly higher contact angle than that of the control chitosan (p < 0.05). After 120 min a bacterial biofilm appeared on the control chitosan, while the phage-linked sample effectively prevented biofilm formation. The TEM images demonstrated that the phage attached and lysed the bacteria on the phage-linked sample at 120 min. The phage-linked sample significantly promoted the neuroblast cell attachment (p < 0.05) and proliferation (p < 0.01). The neuroblast on the phage-linked sample demonstrated more cell extensions after day 1.

CONCLUSION: The purified lytic phages were proven to be a highly bioactive nanomaterial. The phage-chitosan composite material not only promoted neural cell proliferation but also effectively prevent bacterial growth, a major cause of implant failure and removal.}, } @article {pmid35647620, year = {2022}, author = {Lee, JH and Kim, YG and Lee, J}, title = {Inhibition of Staphylococcus aureus Biofilm Formation and Virulence Factor Production by Petroselinic Acid and Other Unsaturated C18 Fatty Acids.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0133022}, pmid = {35647620}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Fatty Acids, Unsaturated ; Hemolysin Proteins/genetics/metabolism ; Humans ; Methicillin/metabolism ; *Methicillin-Resistant Staphylococcus aureus ; Oleic Acids/metabolism ; *Staphylococcal Infections ; Staphylococcus aureus/metabolism ; Virulence Factors/genetics/metabolism ; }, abstract = {Staphylococcus aureus is a major human pathogen that secretes several toxins associated with the pathogenesis of sepsis and pneumonia. Its antibiotic resistance is notorious, and its biofilms play a critical role in antibiotic tolerance. We hypothesized fatty acids might inhibit S. aureus biofilm formation and the expressions of its virulence factors. Initially, the antibiofilm activities of 27 fatty acids against a methicillin-sensitive S. aureus strain were investigated. Of the fatty acids tested, three C18 unsaturated fatty acids, that is, petroselinic, vaccenic, and oleic acids at 100 μg/mL, inhibited S. aureus biofilm formation by more than 65% without affecting its planktonic cell growth (MICs were all > 400 μg/mL). Notably, petroselinic acid significantly inhibited biofilm formation of two methicillin-resistant S. aureus strains and two methicillin-sensitive S. aureus strains. In addition, petroselinic acid significantly suppressed the production of three virulence factors, namely, staphyloxanthin, lipase, and α-hemolysin. Transcriptional analysis showed that petroselinic acid repressed the gene expressions of quorum sensing regulator agrA, effector of quorum sensing RNAIII, α-hemolysin hla, nucleases nuc1 and nuc2, and the virulence regulator saeR. Furthermore, petroselinic acid dose-dependently inhibited S. aureus biofilm formation on abiotic surfaces and porcine skin. These findings suggest that fatty acids, particularly petroselinic acid, are potentially useful for controlling biofilm formation by S. aureus. IMPORTANCE Fatty acids with a long carbon chain have recently attracted attention because of their antibiofilm activities against microbes. Here, we report the antibiofilm activities of 27 fatty acids against S. aureus. Of the fatty acids tested, three C18 unsaturated fatty acids (petroselinic, vaccenic, and oleic acids) significantly inhibited biofilm formation by S. aureus. Furthermore, petroselinic acid inhibited the production of several virulence factors in S. aureus. The study also reveals that the action mechanism of petroselinic acid involves repression of quorum-sensing-related and virulence regulator genes. These findings show that natural and nontoxic petroselinic acid has potential use as a treatment for S. aureus infections, including infections by methicillin-resistant S. aureus strains, and in food processing facilities.}, } @article {pmid35645826, year = {2022}, author = {Meng, Q and Lin, F and Ling, B}, title = {In Vitro Activity of Peptide Antibiotics in Combination With Other Antimicrobials on Extensively Drug-Resistant Acinetobacter baumannii in the Planktonic and Biofilm Cell.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {890955}, pmid = {35645826}, issn = {1663-9812}, abstract = {Acinetobacter baumannii is one of the most dangerous opportunistic pathogens in the global health care setup. Its drug resistance and biofilm-forming capability are often associated with chronic infections that are difficult to treat. Therefore, the clinical treatments for highly drug-resistant A. baumannii are limited. Antimicrobial peptides are broad-spectrum antibacterial agents combined with antibiotics that minimize selective bacterial resistance and enhance antibacterial efficacy. The current study evaluated the synergistic antibacterial activities of clinically important peptide antibiotics combined with other antimicrobials against nine extensively drug-resistant A. baumannii strains in planktonic and biofilm cells in vitro. Polymyxin B and E combined with imipenem showed 100% synergy in the planktonic cell with the checkerboard. Moreover, polymyxin E with rifampicin and bacitracin with imipenem or meropenem showed 100% additive effects. In the biofilm cell, polymyxin B and E combined with azithromycin showed 100% synergy, when vancomycin with azithromycin, rifampicin, and bacitracin with azithromycin or rifampicin, and teicoplanin with tigecycline or rifampicin, all showed 100% additive effects. Therefore, peptide antibiotics combined with other antimicrobials have synergistic or additive effects on extensively drug-resistant A. baumannii in planktonic and biofilm cells. In addition, the combination of polymyxins with carbapenems or azithromycin could be an ideal therapy against extensively drug-resistant A. baumannii infections.}, } @article {pmid35645800, year = {2022}, author = {Shah, AB and Baiseitova, A and Kim, JH and Lee, YH and Park, KH}, title = {Inhibition of Bacterial Neuraminidase and Biofilm Formation by Ugonins Isolated From Helminthostachys Zeylanica (L.) Hook.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {890649}, pmid = {35645800}, issn = {1663-9812}, abstract = {Bacterial neuraminidase (BNA) plays a pivotal role in the pathogenesis of several microbial diseases including biofilm formation. The aim of this study is to reveal the neuraminidase inhibitory potential of metabolites from Helminthostachys zeylanica (L.) Hook. which have diverse biological activities including PTP1B and α-glucosidase. The six ugonins (1-6) from the target plant showed significant neuraminidase inhibition. The inhibitory potencies were observed at a nanomolar level of 35-50 nM, which means they are 100 times more active than their corresponding mother compounds (eriodyctiol and luteolin). A detailed kinetic study revealed that all ugonins were reversible noncompetitive inhibitors. An in-depth investigation of the most potent compound 1 showed its time-dependent inhibition with the isomerization model having k 5 = 0.0103 min[-1], k 6 = 0.0486 min[-1], and K i [app] = 0.062 μM. The binding affinities (K sv) were agreed closely with our prediction based on the inhibitory potencies. Particularly, ugonin J (1) blocked the biofilm formation of E. coli dose-dependently up to 150 µM without the inhibition of bacteria. The major compounds (1-6) in the extract were characterized by UPLC-ESI-Q-TOF/MS.}, } @article {pmid35644451, year = {2022}, author = {Lu, W and Zhang, X and Zhang, Y and Wang, Q and Wei, Y and Ma, B}, title = {Synergistic simultaneous endogenous partial denitrification/anammox (EPDA) and denitrifying dephosphatation for advanced nitrogen and phosphorus removal in a complete biofilm system.}, journal = {Bioresource technology}, volume = {358}, number = {}, pages = {127378}, doi = {10.1016/j.biortech.2022.127378}, pmid = {35644451}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Nitrification ; *Nitrogen ; Oxidation-Reduction ; *Phosphorus ; RNA, Ribosomal, 16S/genetics ; Sewage/microbiology ; Wastewater ; }, abstract = {To achieve simultaneous biological nitrogen and phosphorus removal from municipal wastewater, the endogenous partial denitrification/anammox (EPDA) was combined with denitrifying dephosphatation in a complete biofilm reactor. Advanced nitrogen and phosphorus removal were achieved with effluent total nitrogen (TN) and PO4[3-]-P concentrations of 7.77 ± 0.33 mg/L and 0.35 ± 0.10 mg/L, respectively. Anammox took a major role in the system, accounting for 76 ± 7% of nitrogen removal. 16S rRNA high-throughput sequencing results showed that the anammox bacteria co-existed with the denitrifying glycogen accumulating organisms (DGAOs) and the denitrifying phosphorus accumulating organisms (DPAOs). Anammox bacteria were mainly distributed in the inner layer, while DGAOs and DPAOs existed in the outer layer of EPDA biofilms. Furthermore, based on the EPDA biofilm system, a promising advanced nitrogen and phosphorus removal process was suggested to achieve lower requirements for energy and reagent consumption.}, } @article {pmid35643294, year = {2022}, author = {Villarreal-Salazar, V and Bocanegra-Ibarias, P and Villarreal-Treviño, L and Salas-Treviño, D and Morfin-Otero, R and Camacho-Ortiz, A and Flores-Treviño, S}, title = {Improvement of antimicrobial susceptibility testing in biofilm-growingcoagulase-negative Staphylococcus hominis.}, journal = {Journal of microbiological methods}, volume = {198}, number = {}, pages = {106493}, doi = {10.1016/j.mimet.2022.106493}, pmid = {35643294}, issn = {1872-8359}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Microbial Sensitivity Tests ; Plankton ; Staphylococcus ; *Staphylococcus hominis ; }, abstract = {Coagulase-negative Staphylococcus hominis causes bloodstream infections and often can form biofilms on medical devices. This study aimed to improve the current methodology for antimicrobial susceptibility testing (AST) in biofilm-growing S. hominis isolates. Biofilm production of S. hominis was assessed using the crystal violet staining method in trypticase soy broth supplemented with 1% glucose (TSBglu1%), Mueller-Hinton broth (MHB), or MHBglu1% using flat-bottom plates or the Calgary device. Susceptibility to antibiotics was assessed using the broth microdilution method (MHB and TSBglu1%) in planktonic cells (round-bottom plates) and biofilm cells (flat-bottom plates and the Calgary device). Biofilm determination using TSBglu1% yielded better performance over MHB, and flat-bottom plates without agitation were preferred over the Calgary device. Higher fold dilution values between the minimum biofilm eradication concentration (MBEC) and the minimum inhibitory concentration (MIC) were obtained in MHB for almost all antibiotics, except for linezolid. TSBglu1% and flat-bottom polystyrene plates were preferred over MHB and the Calgary device for biofilm determination. AST in biofilm-growing S. hominis showed better performance using TSBglu1% compared to MHB. Therefore, when comparing MBEC and MIC values, AST in planktonic cells could also be performed using TSBglu1% instead of MHB.}, } @article {pmid35642853, year = {2022}, author = {Wang, H and Chen, C and Yang, E and Tu, Z and Liang, J and Dai, X and Chen, H}, title = {Revealing the effect of biofilm formation in partial nitritation-anammox systems: Start-up, performance stability, and recovery.}, journal = {Bioresource technology}, volume = {357}, number = {}, pages = {127379}, doi = {10.1016/j.biortech.2022.127379}, pmid = {35642853}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Nitrogen ; Oxidation-Reduction ; *Sewage ; Wastewater ; }, abstract = {Successful application of partial nitritation-anammox (PNA) processes is currently and primarily associated with biofilm systems. Biofilm characteristics significantly influence start-up, performance stability, and recovery. Here, two PNA systems with and without carriers were implemented simultaneously for treating wastewater containing 50 mg-NH4/L. The performance characteristics of these two PNA systems were compared. Stable nitrogen removal efficiencies of 76.3 ± 2.8% and 72.9 ± 1.6% were obtained for suspended sludge and biofilm systems, respectively. The slow process of biofilm colonization resulted in a long start-up time in the biofilm system. Biofilm enrichment and protection conferred stable performance when exposed to aeration shock. The suspended sludge system displayed good elasticity during performance recovery after shock compared to the slow recovery in the biofilm system. Moreover, suitable control of dissolved oxygen could improve the activity and abundance of the functional microbes. This study provides new insights into the operation and control of PNA systems for treating mainstream wastewater.}, } @article {pmid35642782, year = {2022}, author = {Moore-Ott, JA and Chiu, S and Amchin, DB and Bhattacharjee, T and Datta, SS}, title = {A biophysical threshold for biofilm formation.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {35642782}, issn = {2050-084X}, mesh = {Bacteria ; *Biofilms ; Biophysics ; Plankton ; *Quorum Sensing ; }, abstract = {Bacteria are ubiquitous in our daily lives, either as motile planktonic cells or as immobilized surface-attached biofilms. These different phenotypic states play key roles in agriculture, environment, industry, and medicine; hence, it is critically important to be able to predict the conditions under which bacteria transition from one state to the other. Unfortunately, these transitions depend on a dizzyingly complex array of factors that are determined by the intrinsic properties of the individual cells as well as those of their surrounding environments, and are thus challenging to describe. To address this issue, here, we develop a generally-applicable biophysical model of the interplay between motility-mediated dispersal and biofilm formation under positive quorum sensing control. Using this model, we establish a universal rule predicting how the onset and extent of biofilm formation depend collectively on cell concentration and motility, nutrient diffusion and consumption, chemotactic sensing, and autoinducer production. Our work thus provides a key step toward quantitatively predicting and controlling biofilm formation in diverse and complex settings.}, } @article {pmid35642502, year = {2022}, author = {Schoepflin, S and Macmanus, J and Long, C and McCullough, K and Klaus, S and De Clippeleir, H and Wilson, C and Parsons, M and Chandran, K and Bott, C}, title = {Startup strategies for mainstream anammox polishing in moving bed biofilm reactors.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {94}, number = {6}, pages = {e10723}, doi = {10.1002/wer.10723}, pmid = {35642502}, issn = {1554-7531}, support = {84008601/EPA/EPA/United States ; 84008601/EPA/EPA/United States ; }, mesh = {Ammonia ; Anaerobic Ammonia Oxidation ; *Biofilms ; Bioreactors/microbiology ; *Nitrites ; }, abstract = {This study evaluated startup strategies for mainstream polishing anammox moving bed biofilm reactors (MBBRs) without anammox bacterial (AMX) biomass inoculation. Two types of startups were tested: anammox only (no external carbon addition) and partial denitrification/anammox (PdNA) with glycerol addition. Reactors were started with either virgin carriers or carriers with a preliminary biofilm from a mainstream aerobic integrated fixed-film activated sludge (IFAS) process. Three pilot-scale startups were completed under the following conditions: anammox-only with preliminary biofilm carriers, PdNA with preliminary biofilm carriers, and PdNA with virgin carriers. AMX presence was confirmed via quantitative polymerase chain reaction (qPCR) after 57, 57, and 77 days, respectively. Prior to AMX detection, average influent concentrations of ammonia and nitrite ranged from 1.7-2.7 mg/L and 0.98-1.8 mg/L, respectively. This study demonstrated that AMX can be grown on carriers without AMX seeding under mainstream conditions (temperature 17-29°C, low ammonia and nitrite), regardless of whether nitrite came from upstream or partial denitrification within the reactor. This study also showed that using preliminary biofilm carriers can decrease startup time by approximately 1 month. These results address critical questions for moving mainstream anammox processes to full-scale implementation, and suggest that PdNA MBBRs are feasible and sustainable for full-scale ammonia, nitrate, and nitrite polishing to meet stringent total nitrogen requirements. PRACTITIONER POINTS: This research will help utilities develop methods for starting up mainstream anammox MBBRs without the barrier of anammox biomass seeding. Preliminary biofilm carriers accelerated startup time in a PdNA MBBR, but a virgin carrier reactor started up in a similar timeframe, contrary to expectations. Also, contrary to expectations, high concentrations of ammonia and nitrite are not necessary for startup of an anammox or PdNA MBBR.}, } @article {pmid35640890, year = {2022}, author = {Sadiq, FA and Hansen, MF and Burmølle, M and Heyndrickx, M and Flint, S and Lu, W and Chen, W and Zhang, H}, title = {Trans-kingdom interactions in mixed biofilm communities.}, journal = {FEMS microbiology reviews}, volume = {46}, number = {5}, pages = {}, doi = {10.1093/femsre/fuac024}, pmid = {35640890}, issn = {1574-6976}, mesh = {*Archaea/physiology ; Bacteria/metabolism ; *Biofilms ; Ecosystem ; Plants ; Quorum Sensing ; }, abstract = {The microbial world represents a phenomenal diversity of microorganisms from different kingdoms of life, which occupy an impressive set of ecological niches. Most, if not all, microorganisms once colonize a surface develop architecturally complex surface-adhered communities, which we refer to as biofilms. They are embedded in polymeric structural scaffolds and serve as a dynamic milieu for intercellular communication through physical and chemical signalling. Deciphering microbial ecology of biofilms in various natural or engineered settings has revealed coexistence of microorganisms from all domains of life, including Bacteria, Archaea, and Eukarya. The coexistence of these dynamic microbes is not arbitrary, as a highly coordinated architectural setup and physiological complexity show ecological interdependence and myriads of underlying interactions. In this review, we describe how species from different kingdoms interact in biofilms and discuss the functional consequences of such interactions. We highlight metabolic advances of collaboration among species from different kingdoms, and advocate that these interactions are of great importance and need to be addressed in future research. Since trans-kingdom biofilms impact diverse contexts, ranging from complicated infections to efficient growth of plants, future knowledge within this field will be beneficial for medical microbiology, biotechnology, and our general understanding of microbial life in nature.}, } @article {pmid35640508, year = {2022}, author = {Chen, X and Li, F and Huo, P and Liu, J and Yang, L and Li, X and Wei, W and Ni, BJ}, title = {Influences of longitudinal gradients on methane-driven membrane biofilm reactor for complete nitrogen removal: A model-based investigation.}, journal = {Water research}, volume = {220}, number = {}, pages = {118665}, doi = {10.1016/j.watres.2022.118665}, pmid = {35640508}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Methane ; *Nitrogen ; Oxidation-Reduction ; Prospective Studies ; Wastewater ; }, abstract = {Integrating anammox with denitrifying anaerobic methane oxidation (DAMO) in the membrane biofilm reactor (MBfR) is a promising technology capable of achieving complete nitrogen removal from wastewater. However, it remains unknown whether reactor configurations featuring longitudinal gradients parallel to the membrane surface would affect the performance of the CH4-driven MBfR. To this end, this work aims to study the impacts of longitudinal heterogeneity potentially present in the gas and liquid phases on a representative CH4-driven MBfR performing anammox/DAMO by applying the reported modified compartmental modeling approach. Through comparing the modeling results of different reactor configurations, this work not only offered important guidance for better design, operation and monitoring of the CH4-driven MBfR, but also revealed important implications for prospective related modeling research. The total nitrogen removal efficiency of the MBfR at non-excessive CH4 supply (e.g., surface loading of ≤0.064 g-COD m[-2] d[-1] in this work) was found to be insensitive to both longitudinal gradients in the liquid and gas phases. Comparatively, the longitudinal gradient in the liquid phase led to distinct longitudinal biomass stratification and therefore played an influential role in the effective CH4 utilization efficiency, which was also related to the extent of reactor compartmentation considered in modeling. When supplied with non-excessive CH4, the MBfR is recommended to be designed/operated with both the biofilm reactor and the membrane lumen as plug flow reactors (PFRs) with co-current flow of wastewater and CH4, which could mitigate dissolved CH4 discharge in the effluent. For the reactor configurations with the biofilm reactor designed/operated as a PFR, multi-spot sampling in the longitudinal direction is needed to obtain a correct representation of the microbial composition of the MBfR.}, } @article {pmid35638465, year = {2022}, author = {Lisac, A and Birsa, E and Podgornik, A}, title = {E. coli biofilm formation and its susceptibility towards T4 bacteriophages studied in a continuously operating mixing - tubular bioreactor system.}, journal = {Microbial biotechnology}, volume = {15}, number = {9}, pages = {2450-2463}, pmid = {35638465}, issn = {1751-7915}, mesh = {Bacteria ; Bacteriophage T4 ; *Bacteriophages/physiology ; Biofilms ; Bioreactors ; *Escherichia coli/physiology ; Plankton ; }, abstract = {A system consisting of a connected mixed and tubular bioreactor was designed to study bacterial biofilm formation and the effect of its exposure to bacteriophages under different experimental conditions. The bacterial biofilm inside silicone tubular bioreactor was formed during the continuous pumping of bacterial cells at a constant physiological state for 2 h and subsequent washing with a buffer for 24 h. Monitoring bacterial and bacteriophage concentration along the tubular bioreactor was performed via a piercing method. The presence of biofilm and planktonic cells was demonstrated by combining the piercing method, measurement of planktonic cell concentration at the tubular bioreactor outlet, and optical microscopy. The planktonic cell formation rate was found to be 8.95 × 10[-3] h[-1] and increased approximately four-fold (4×) after biofilm exposure to an LB medium. Exposure of bacterial biofilm to bacteriophages in the LB medium resulted in a rapid decrease of biofilm and planktonic cell concentration, to below the detection limit within < 2 h. When bacteriophages were supplied in the buffer, only a moderate decrease in the concentration of both bacterial cell types was observed. After biofilm washing with buffer to remove unadsorbed bacteriophages, its exposure to the LB medium (without bacteriophages) resulted in a rapid decrease in bacterial concentration: again below the detection limit in < 2 h.}, } @article {pmid35638423, year = {2022}, author = {Koehler, T and Wingender, J and Lueling, M and Meckelmann, SW and Telgheder, U and Schmitz, OJ}, title = {Characterization of the Extracellular Volatile Metabolome of Pseudomonas Aeruginosa Applying an in vitro Biofilm Model under Cystic Fibrosis-Like Conditions.}, journal = {Frontiers in bioscience (Landmark edition)}, volume = {27}, number = {5}, pages = {156}, doi = {10.31083/j.fbl2705156}, pmid = {35638423}, issn = {2768-6698}, mesh = {Biofilms ; *Cystic Fibrosis ; Humans ; Metabolome ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/genetics/metabolism ; }, abstract = {BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive hereditary disease that leads to the production of thickened mucus in the lungs, favouring polymicrobial infections, such as chronic lung infections with the bacterial opportunistic pathogen Pseudomonas aeruginosa.

METHOD: A biofilm model in combination with an adapted sampling and GC-MS analysis method were applied to in vitro studies on different variables influencing the composition of the extracellular volatile metabolome of P. aeruginosa.

RESULTS: A significant influence on the metabolome could be demonstrated for the culture medium as well as the atmosphere during cultivation (aerobic or anaerobic). Furthermore, a significant influence of the mucoid (alginate-overproducing) phenotype of the bacterium on quantity and composition of volatile organic compounds could be observed. Based on the results a solid culture medium was developed to simulate the nutrient conditions in the lungs of a CF patient. The extracellular volatile metabolome of bacterial strains P. aeruginosa ATCC 10145, PAO1 and FRD1 was characterized under CF-like conditions.

CONCLUSIONS: Bacterial strain-dependent metabolites were identified. When P. aeruginosa PAO1 and FRD1 clinical isolates were compared, 36 metabolites showed significant variations in intensities. When the clinical isolates were compared with the reference strain (P. aeruginosa ATCC 10145), 28 metabolites (P. aeruginosa PAO1) and 70 metabolites (P. aeruginosa FRD1) were determined whose peaks showed significant deviation (p > 95%) in intensity. Furthermore, the bacterial strains could be differentiated from each other by means of two principal components.}, } @article {pmid35636603, year = {2022}, author = {Shitu, A and Zhang, Y and Danhassan, UA and Li, H and Tadda, MA and Ye, Z and Zhu, S}, title = {Synergistic effect of chitosan-based sludge aggregates CS@NGS inoculum accelerated the start-up of biofilm reactor treating aquaculture effluent: Insights into performance, microbial characteristics, and functional genes.}, journal = {Chemosphere}, volume = {303}, number = {Pt 3}, pages = {135097}, doi = {10.1016/j.chemosphere.2022.135097}, pmid = {35636603}, issn = {1879-1298}, mesh = {Aquaculture ; Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; *Chitosan ; Nitrites/metabolism ; Nitrogen/metabolism ; *Sewage/microbiology ; Wastewater/microbiology ; }, abstract = {The moving bed bioreactor (MBBR) process has drawn more attention as a promising biological wastewater treatment process. Nevertheless, achieving quick start-up and microbial biofilm formation remains a significant challenge. Consequently, the present study investigated a novel chitosan-based natural sludge (CS@NGS) seeding strategy for the accelerated start-up of MBBR. Three identical bioreactors were employed; the first bioreactor was without sludge seed as the control (BR1), the second was inoculated only with sludge (BR2), and the third was inoculated with CS@NGS according to the proposed seeding method (BR3). All bioreactors were utilised to treat simulated recirculating aquaculture systems (RAS) effluent. Resultantly, the CS@NGS shortened the start-up period from over twenty to seven days due to the enhanced initial microbial adhesion and biofilm formation. Under optimal conditions, the ammonium removal in BR3 approached 100%, which was relatively higher than BR2 (96.35 ± 1.12%) and BR1 (92.56 ± 2.17%). Moreover, a low nitrite accumulation was exhibited in the effluents, approximately ≤0.03 mg L[-1]. The process performance correlated positively with core bacteria from the genera Nakamurella, Hyphomicrobium, Nitrospira, Paenarthrobacter, Rhodococcus, and Stenotrophobacter. The quantitative polymerase chain reaction (qPCR) results demonstrated that the CS@NGS enhanced the expressions of amoA, nxrB, nirK, nirS, narG, and napA nitrogen metabolism-related functional genes to varying degrees. The present study findings can assist the rapid start-up of aquaculture biofilters utilised to solve high nitrite and ammonia accumulation in recirculated water from industrial RAS.}, } @article {pmid35636549, year = {2022}, author = {Xue, Z and Zhang, T and Sun, Y and Yin, T and Cao, J and Fang, F and Feng, Q and Luo, J}, title = {Integrated moving bed biofilm reactor with partial denitrification-anammox for promoted nitrogen removal: Layered biofilm structure formation and symbiotic functional microbes.}, journal = {The Science of the total environment}, volume = {839}, number = {}, pages = {156339}, doi = {10.1016/j.scitotenv.2022.156339}, pmid = {35636549}, issn = {1879-1026}, mesh = {Anaerobic Ammonia Oxidation ; Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; *Nitrogen/chemistry ; Oxidation-Reduction ; Sewage/microbiology ; Wastewater/chemistry ; }, abstract = {Partial denitrification/anaerobic ammonia oxidation (anammox) (PD/A) is currently an advanced nitrogen removal process. This study developed a PD/A system in a moving bed biofilm reactor. Results showed that the nitrogen removal efficiency reached 76.60% with a COD/NO3-N of 2.0, and the contribution of anammox was 88.01%. Further analysis showed that the biocarriers could form layered pH and dissolved oxygen structures to promote the aggregation of different functional bacteria at various depths, thus stabilizing the coupled process. Microbial structure analysis showed that the abundance of Saccharimonadales, responsible for denitrification, increased from 0% to 36.27% between day 0 and day 120, while the abundance of Candidatus Jettenia, responsible for anammox, decreased from 10.41% to 2.20%. The synergistic effect of Saccharimonadales and Candidatus Jettenia enabled stable and efficient removal of nitrogen. This study proposed a novel configuration of the PD/A process and provided a theoretical basis for its promotion and application.}, } @article {pmid35636093, year = {2022}, author = {de Melo, ALF and Rossato, L and Barbosa, MDS and Palozi, RAC and Alfredo, TM and Antunes, KA and Eduvirgem, J and Ribeiro, SM and Simionatto, S}, title = {From the environment to the hospital: How plants can help to fight bacteria biofilm.}, journal = {Microbiological research}, volume = {261}, number = {}, pages = {127074}, doi = {10.1016/j.micres.2022.127074}, pmid = {35636093}, issn = {1618-0623}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; *Biofilms ; Hospitals ; *Plants, Medicinal ; }, abstract = {The emergence of resistance to antibiotics has become a global challenge as far as the control and treatment of nosocomial infections are concerned. Compared to the planktonic state, biofilms generally confer more resistance to antibiotics and may become a potential source of infection. Researchers are thus focused on developing novel drugs not as vulnerable as the current ones to bacterial resistance mechanisms and also able to target bacteria in biofilms. Natural products, especially those derived from plant sources, have substantiated significant medicinal activity with unique properties, making them perfect candidates for these much-needed therapeutics. Despite being a vast resource of antimicrobial molecules, limitations, including the low concentration of the extracted active compound and bioavailability, challenge the clinical application of medicinal plants to combat these infections. Nanotechnology through green synthesis is one of the strategies to explore the medicinal potential of plants. Research has established the promising outcome of this method in antibiofilm activity, in addition to improved drug delivery, targeting, and pharmacokinetic profiles. This review summarized the current knowledge on the potentialities of plant products as antibiotic adjuvants to restore the therapeutic activity of drugs. We also discussed biotechnological advances in medicinal plants to fight and eradicate biofilm-forming microorganisms.}, } @article {pmid35635951, year = {2022}, author = {Wang, L and Liu, L and Wang, X and Tan, Y and Duan, X and Zhang, C and Cheng, J and Xiong, Y and Jiang, G and Wang, J and Liao, X}, title = {Ruthenium(II) complexes targeting membrane as biofilm disruptors and resistance breakers in Staphylococcus aureus bacteria.}, journal = {European journal of medicinal chemistry}, volume = {238}, number = {}, pages = {114485}, doi = {10.1016/j.ejmech.2022.114485}, pmid = {35635951}, issn = {1768-3254}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria ; Biofilms ; Mice ; Microbial Sensitivity Tests ; *Ruthenium/chemistry/pharmacology ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; }, abstract = {The development of ruthenium-based complexes or antimicrobial peptides are identified as a promising strategy for combating drug-resistant bacteria. In this work, four biphenyl-based antibacterial ruthenium complexes by targeting membrane integrity, which act as antimicrobial peptides mimics, were designed and synthesized. In vitro antimicrobial screening demonstrated that four complexes could absolutely inhibit the growth of Staphylococcus aureus (S. aureus) with MIC values ranging from 15.6 to 100 μg/mL. The most active complex Ru(Ⅱ)-1 (MIC = 15.6 μg/mL) could kill S. aureus through targeting the membrane integrity without detectably resistance frequencies. Further investigation including bacteria biofilm formation, hemolysin activity and checkerboard assay were performed as well. The results revealed that Ru(Ⅱ)-1 could inhibit the biofilm formation and α-hemolysis secretion in S. aureus at subinhibitory concentration. More interestingly, the combination use of Ru(Ⅱ)-1 and five traditional antibiotics showing synergistic effect. Finally, based on the mouse model of S. aureus skin infection, Ru(Ⅱ)-1 showed important antibacterial efficacy against S. aureus in vivo, and almost non-toxic against mouse tissue. Our study indicates that introducing membrane targeting ligands onto ruthenium complexes may be an underappreciated strategy for developing antibacterial agents.}, } @article {pmid35634916, year = {2022}, author = {Prasad, B and Shaikh, S and Saini, R and Wang, Q and Zadoo, S and Sadaphal, V and Greenberg, DE and Chopra, R}, title = {Quantifying the relationship between biofilm reduction and thermal tissue damage on metal implants exposed to alternating magnetic fields.}, journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group}, volume = {39}, number = {1}, pages = {713-724}, doi = {10.1080/02656736.2022.2065038}, pmid = {35634916}, issn = {1464-5157}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Magnetic Fields ; Metals ; *Prostheses and Implants/adverse effects ; }, abstract = {AIM: Metal implant infections are a devastating problem due to the formation of biofilm which impairs the effectiveness of antibiotics and leads to surgical replacement as definitive treatment. Biofilm on metal implants can be reduced using heat generated by alternating magnetic fields (AMF). In this study, the relationship between implant surface biofilm reduction and surrounding tissue thermal damage during AMF exposure is investigated through numerical simulations.

METHODS: Mathematical models of biofilm reduction with heat were created based on in vitro experiments. Simulations were performed to predict the spatial and temporal heating on the implant surface and surrounding tissue when exposed to AMF.

RESULTS: The modeling results show that intermittent and slow heating can achieve biofilm reduction with a narrow zone of tissue damage around an implant of less than 3 mm. The results also emphasize that uniformity of implant heating is an extremely important factor impacting the effectiveness of biofilm reduction. For a knee implant, using a target temperature of 75 °C, an intermittent treatment strategy of 15 exposures (10 s to target temperature followed by cooldown) achieved a bacterial CFU reduction of 6-log10 across 25% of the implant surface with less than 3 mm of tissue damage. Alternatively, a single 60 s heating exposure to same temperature achieved a bacterial reduction of 6-log10 across 85% of the implant surface, but with 4 mm of tissue damage.

CONCLUSION: Overall, this study demonstrates that with uniform heating to temperatures above 70 °C, an implant surface can be largely reduced of biofilm, with only a few mm of surrounding tissue damage.}, } @article {pmid35633295, year = {2023}, author = {Grønseth, T and Ovchinnikov, KV and Carlsen, H and Benth, JŠ and Diep, DB and von Unge, M and Silvola, JT}, title = {Lugol's solution and Gentian violet eradicate methicillin-resistant Staphylococcus aureus biofilm in skin wound infections.}, journal = {International wound journal}, volume = {20}, number = {1}, pages = {120-130}, pmid = {35633295}, issn = {1742-481X}, support = {//Universitetet i Oslo/ ; }, mesh = {Animals ; Mice ; *Methicillin-Resistant Staphylococcus aureus ; Gentian Violet/therapeutic use ; Staphylococcus aureus ; Anti-Bacterial Agents/therapeutic use ; *Skin Diseases, Infectious ; *Wound Infection/drug therapy ; *Soft Tissue Injuries/drug therapy ; Biofilms ; }, abstract = {The study aimed to evaluate the antibacterial efficacy of Lugol's solution 5% and Gentian violet 1% against methicillin-resistant Staphylococcus aureus (MRSA) biofilm in vivo. The bactericidal efficacy for treatment of MRSA-biofilm skin wound infection was tested in a murine model. Luciferase-tagged S. aureus Xen31, a MRSA-strain derived from S. aureus ATCC-3359130, was used for infection. Wounds were made in the skin of mice and infected with MRSA. The mice were treated with Lugol's solution and Gentian violet. Application of the antimicrobial agents started 24 hours post infection and was repeated daily for five-days. The antimicrobial effect on the biofilm bacteria was evaluated by measuring bioluminescence from MRSA daily for seven-days. Lugol's solution and Gentian violet showed a significant reduction in luminescent signals from the first assessment day to all subsequent days (P < .001). Lugol's solution and Gentian violet effectively eradicated MRSA in biofilm in vivo and could be alternatives or in addition to topical antibiotics when MRSA-biofilm wound infection is suspected.}, } @article {pmid35632801, year = {2022}, author = {Visnapuu, A and Van der Gucht, M and Wagemans, J and Lavigne, R}, title = {Deconstructing the Phage-Bacterial Biofilm Interaction as a Basis to Establish New Antibiofilm Strategies.}, journal = {Viruses}, volume = {14}, number = {5}, pages = {}, pmid = {35632801}, issn = {1999-4915}, support = {819800/ERC_/European Research Council/International ; }, mesh = {Bacteria/genetics ; *Bacteriophages/genetics ; Biofilms ; }, abstract = {The bacterial biofilm constitutes a complex environment that endows the bacterial community within with an ability to cope with biotic and abiotic stresses. Considering the interaction with bacterial viruses, these biofilms contain intrinsic defense mechanisms that protect against phage predation; these mechanisms are driven by physical, structural, and metabolic properties or governed by environment-induced mutations and bacterial diversity. In this regard, horizontal gene transfer can also be a driver of biofilm diversity and some (pro)phages can function as temporary allies in biofilm development. Conversely, as bacterial predators, phages have developed counter mechanisms to overcome the biofilm barrier. We highlight how these natural systems have previously inspired new antibiofilm design strategies, e.g., by utilizing exopolysaccharide degrading enzymes and peptidoglycan hydrolases. Next, we propose new potential approaches including phage-encoded DNases to target extracellular DNA, as well as phage-mediated inhibitors of cellular communication; these examples illustrate the relevance and importance of research aiming to elucidate novel antibiofilm mechanisms contained within the vast set of unknown ORFs from phages.}, } @article {pmid35631633, year = {2022}, author = {Lee, JH and Kim, YG and Park, S and Hu, L and Lee, J}, title = {Phytopigment Alizarin Inhibits Multispecies Biofilm Development by Cutibacterium acnes, Staphylococcus aureus, and Candida albicans.}, journal = {Pharmaceutics}, volume = {14}, number = {5}, pages = {}, pmid = {35631633}, issn = {1999-4923}, support = {2021R1I1A3A04037486//National Research Foundation of Korea/ ; 2022R1C1C2006146//National Research Foundation of Korea/ ; 2021R1A2C1008368//National Research Foundation of Korea/ ; 2014R1A6A1031189//National Research Foundation of Korea/ ; }, abstract = {Acne vulgaris is a common chronic inflammatory skin disease involving Cutibacterium acnes with other skin commensals such as Staphylococcus aureus and Candida albicans in the anaerobic and lipid-rich conditions of pilosebaceous units. These microbes readily form multispecies biofilms that are tolerant of traditional antibiotics as well as host immune systems. The phytopigment alizarin was previously found to prevent biofilm formation by S. aureus and C. albicans strains under aerobic conditions. Hence, we hypothesized that alizarin might control C. acnes and multispecies biofilm development. We found that under anaerobic conditions, alizarin efficiently inhibited single biofilm formation and multispecies biofilm development by C. acnes, S. aureus, and C. albicans without inhibiting planktonic cell growth. Alizarin increased the hydrophilicities of S. aureus and C. albicans cells, decreased lipase production by S. aureus, diminished agglutination by C. acnes, and inhibited the aggregation of C. albicans cells. Furthermore, the co-administration of alizarin and antibiotics enhanced the antibiofilm efficacies of alizarin against C. acnes. A transcriptomic study showed that alizarin repressed the transcriptions of various biofilm-related genes such as lipase, hyaluronate lyase, adhesin/invasion-related, and virulence-related genes of C. acnes. Furthermore, alizarin at 100 µg/mL prevented C. acnes biofilm development on porcine skin. Our results show that alizarin inhibits multispecies biofilm development by acne-causing microbes and suggest it might be a useful agent for treating or preventing C. acnes-causing skin diseases.}, } @article {pmid35631547, year = {2022}, author = {Alzahrani, NM and Booq, RY and Aldossary, AM and Bakr, AA and Almughem, FA and Alfahad, AJ and Alsharif, WK and Jarallah, SJ and Alharbi, WS and Alsudir, SA and Alyamani, EJ and Tawfik, EA and Alshehri, AA}, title = {Liposome-Encapsulated Tobramycin and IDR-1018 Peptide Mediated Biofilm Disruption and Enhanced Antimicrobial Activity against Pseudomonas aeruginosa.}, journal = {Pharmaceutics}, volume = {14}, number = {5}, pages = {}, pmid = {35631547}, issn = {1999-4923}, support = {20-0103 and 20-0051//National Industrial Development and Logistics Program/ ; }, abstract = {The inadequate eradication of pulmonary infections and chronic inflammation are significant complications in cystic fibrosis (CF) patients, who usually suffer from persistent and frequent lung infections caused by several pathogens, particularly Pseudomonas aeruginosa (P. aeruginosa). The ability of pathogenic microbes to protect themselves from biofilms leads to the development of an innate immune response and antibiotic resistance. In the present work, a reference bacterial strain of P. aeruginosa (PA01) and a multidrug-resistant isolate (MDR 7067) were used to explore the microbial susceptibility to three antibiotics (ceftazidime, imipenem, and tobramycin) and an anti-biofilm peptide (IDR-1018 peptide) using the minimum inhibition concentration (MIC). The most effective antibiotic was then encapsulated into liposomal nanoparticles and the IDR-1018 peptide with antibacterial activity, and the ability to disrupt the produced biofilm against PA01 and MDR 7067 was assessed. The MIC evaluation of the tobramycin antibacterial activity showed an insignificant effect on the liposomes loaded with tobramycin and liposomes encapsulating tobramycin and IDR-1018 against both P. aeruginosa strains to free tobramycin. Nevertheless, the biofilm formation was significantly reduced (p < 0.05) at concentrations of ≥4 μg/mL and ≤32 μg/mL for PA01 and ≤32 μg/mL for MDR 7067 when loading tobramycin into liposomes, with or without the anti-biofilm peptide compared to the free antibiotic, empty liposomes, and IDR-1018-loaded liposomes. A tobramycin concentration of ≤256 µg/mL was safe when exposed to a lung carcinoma cell line upon its encapsulation into the liposomal formulation. Tobramycin-loaded liposomes could be a potential candidate for treating lung-infected animal models owing to the high therapeutic efficacy and safety profile of this system compared to the free administration of the antibiotic.}, } @article {pmid35631315, year = {2022}, author = {Woelber, JP and Al-Ahmad, A and Alt, KW}, title = {On the Pathogenicity of the Oral Biofilm: A Critical Review from a Biological, Evolutionary, and Nutritional Point of View.}, journal = {Nutrients}, volume = {14}, number = {10}, pages = {}, pmid = {35631315}, issn = {2072-6643}, mesh = {Biofilms ; Humans ; Life Style ; *Periodontal Diseases/epidemiology/etiology/prevention & control ; Virulence ; }, abstract = {Plaque control is one of the most recommended approaches in the prevention and therapy of caries and periodontal diseases. However, although most individuals in industrialized countries already perform daily oral hygiene, caries and periodontal diseases still are the most common diseases of mankind. This raises the question of whether plaque control is really a causative and effective approach to the prevention of these diseases. From an evolutionary, biological, and nutritional perspective, dental biofilms have to be considered a natural phenomenon, whereas several changes in human lifestyle factors during modern evolution are not "natural". These lifestyle factors include the modern "Western diet" (rich in sugar and saturated fats and low in micronutrients), smoking, sedentary behavior, and continuous stress. This review hypothesizes that not plaque itself but rather these modern, unnatural lifestyle factors are the real causes of the high prevalence of caries and periodontal diseases besides several other non-communicable diseases. Accordingly, applying evolutionary and lifestyle medicine in dentistry would offer a causative approach against oral and common diseases, which would not be possible with oral hygiene approaches used on their own.}, } @article {pmid35631012, year = {2022}, author = {Tokajuk, J and Deptuła, P and Chmielewska, SJ and Skłodowski, K and Mierzejewska, ŻA and Grądzka-Dahlke, M and Tołstoj, A and Daniluk, T and Paprocka, P and Savage, PB and Bucki, R}, title = {Ceragenin CSA-44 as a Means to Control the Formation of the Biofilm on the Surface of Tooth and Composite Fillings.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35631012}, issn = {2076-0817}, support = {UMO-2018/31/B/NZ6/02476//National Science Center/ ; UDA- RPPD.01.01.00-20-001/15-00//Medical University of Bialystok as part of the RPOWP 2007-2013 481 funding, Priority I, Axis 1.1/ ; }, abstract = {Recurrent oral infections, as manifested by endodontic and periodontal disease, are often caused by Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans). Here, we assessed the anti-biofilm activity of ceragenin CSA-44 against these microbes growing as a biofilm in the presence of saliva on the surface of human teeth and dental composite (composite filling) subjected to mechanical stresses. Methods: Biofilm mass analysis was performed using crystal violet (CV) staining. The morphology, viscoelastic properties of the biofilm after CSA-44 treatment, and changes in the surface of the composite in response to biofilm presence were determined by AFM microscopy. Results: CSA-44 prevented biofilm formation and reduced the mass of biofilm formed by tested microorganisms on teeth and dental composite. Conclusion: The ability of CSA-44 to prevent the formation and to reduce the presence of established biofilm on tooth and composite filling suggests that it can serve as an agent in the development of new methods of combating oral pathogens and reduce the severity of oral infections.}, } @article {pmid35630711, year = {2022}, author = {Yu, T and Jiang, X and Xu, X and Jiang, C and Kang, R and Jiang, X}, title = {Andrographolide Inhibits Biofilm and Virulence in Listeria monocytogenes as a Quorum-Sensing Inhibitor.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {10}, pages = {}, pmid = {35630711}, issn = {1420-3049}, support = {20200148//the Cultivation Fund of the National Scientific Research Project of Henan Normal University/ ; 222300420470, 212300410220 and 202300410018//the Natural Science Foundation of Henan Province/ ; 22A180003//the Key Project of Natural Science of the Education Department of Henan Province/ ; 2021GGJS162//Henan Province Young Backbone Teacher Project/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Caco-2 Cells ; Diterpenes ; Humans ; *Listeria monocytogenes ; Virulence ; }, abstract = {Listeria monocytogenes is a major foodborne pathogen that can cause listeriosis in humans and animals. Andrographolide is known as a natural antibiotic and exhibits good antibacterial activity. We aimed to investigate the effect of andrographolide on two quorum-sensing (QS) systems, LuxS/AI-2 and Agr/AIP of L. monocytogenes, as well as QS-controlled phenotypes in this study. Our results showed that neither luxS expression nor AI-2 production was affected by andrographolide. Nevertheless, andrographolide significantly reduced the expression levels of the agr genes and the activity of the agr promoter P2. Results from the crystal violet staining method, confocal laser scanning microscopy (CLSM), and field emission scanning electron microscopy (FE-SEM) demonstrated that andrographolide remarkably inhibited the biofilm-forming ability of L. monocytogenes 10403S. The preformed biofilms were eradicated when exposed to andrographolide, and reduced surviving cells were also observed in treated biofilms. L. monocytogenes treated with andrographolide exhibited decreased ability to secrete LLO and adhere to and invade Caco-2 cells. Therefore, andrographolide is a potential QS inhibitor by targeting the Agr QS system to reduce biofilm formation and virulence of L. monocytogenes.}, } @article {pmid35630468, year = {2022}, author = {Patel, M and Siddiqui, AJ and Ashraf, SA and Surti, M and Awadelkareem, AM and Snoussi, M and Hamadou, WS and Bardakci, F and Jamal, A and Jahan, S and Sachidanandan, M and Adnan, M}, title = {Lactiplantibacillus plantarum-Derived Biosurfactant Attenuates Quorum Sensing-Mediated Virulence and Biofilm Formation in Pseudomonas aeruginosa and Chromobacterium violaceum.}, journal = {Microorganisms}, volume = {10}, number = {5}, pages = {}, pmid = {35630468}, issn = {2076-2607}, support = {RG-20094//University of Hail/ ; }, abstract = {Quorum sensing (QS) controls the expression of diverse biological traits in bacteria, including virulence factors. Any natural bioactive compound that disables the QS system is being considered as a potential strategy to prevent bacterial infection. Various biological activities of biosurfactants have been observed, including anti-QS effects. In the present study, we investigated the effectiveness of a biosurfactant derived from Lactiplantibacillus plantarum on QS-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Chromobacterium violaceum. The structural analogues of the crude biosurfactant were identified using gas chromatography-mass spectrometry (GC-MS). Moreover, the inhibitory prospects of identified structural analogues were assessed with QS-associated CviR, LasA, and LasI ligands via in silico molecular docking analysis. An L. plantarum-derived biosurfactant showed a promising dose-dependent interference with the production of both violacein and acyl homoserine lactone (AHL) in C. violaceum. In P. aeruginosa, at a sub-MIC concentration (2.5 mg/mL), QS inhibitory activity was also demonstrated by reduction in pyocyanin (66.63%), total protease (60.95%), LasA (56.62%), and LasB elastase (51.33%) activity. The swarming motility and exopolysaccharide production were also significantly reduced in both C. violaceum (61.13%) and P. aeruginosa (53.11%). When compared with control, biofilm formation was also considerably reduced in C. violaceum (68.12%) and P. aeruginosa (59.80%). A GC-MS analysis confirmed that the crude biosurfactant derived from L. plantarum was a glycolipid type. Among all, n-hexadecanoic acid, oleic acid, and 1H-indene,1-hexadecyl-2,3-dihydro had a high affinity for CviR, LasI, and LasA, respectively. Thus, our findings suggest that the crude biosurfactant of L. plantarum can be used as a new anti-QS/antibiofilm agent against biofilm-associated pathogenesis, which warrants further investigation to uncover its therapeutic efficacy.}, } @article {pmid35630375, year = {2022}, author = {Soares, A and Gomes, LC and Monteiro, GA and Mergulhão, FJ}, title = {Hydrodynamic Effects on Biofilm Development and Recombinant Protein Expression.}, journal = {Microorganisms}, volume = {10}, number = {5}, pages = {}, pmid = {35630375}, issn = {2076-2607}, support = {LA/P/0045/2020 (ALiCE), UIDB/00511/2020 and UIDP/00511/2020 (LEPABE)//FCT/MCTES (PIDDAC)/ ; PTDC/BII-BIO/29589/2017 - POCI-01-0145-FEDER-029589//FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES/ ; SFRH/BD/141614/2018; CEECIND/01700/2017//FCT/ ; }, abstract = {Hydrodynamics play an important role in the rate of cell attachment and nutrient and oxygen transfer, which can affect biofilm development and the level of recombinant protein production. In the present study, the effects of different flow conditions on the development of Escherichia coli biofilms and the expression of a model recombinant protein (enhanced green fluorescent protein, eGFP) were examined. Planktonic and biofilm cells were grown at two different flow rates in a recirculating flow cell system for 7 days: 255 and 128 L h[-1] (corresponding to a Reynolds number of 4600 and 2300, respectively). The fluorometric analysis showed that the specific eGFP production was higher in biofilms than in planktonic cells under both hydrodynamic conditions (3-fold higher for 255 L h[-1] and 2-fold higher for 128 L h[-1]). In the biofilm cells, the percentage of eGFP-expressing cells was on average 52% higher at a flow rate of 255 L h[-1]. Furthermore, a higher plasmid copy number (PCN) was obtained for the highest flow rate for both planktonic (244 PCN/cell versus 118 PCN/cell) and biofilm cells (43 PCN/cell versus 29 PCN/cell). The results suggested that higher flow velocities promoted eGFP expression in E. coli biofilms.}, } @article {pmid35630353, year = {2022}, author = {Shimizu, T and Aritoshi, T and Beatty, JT and Masuda, T}, title = {Persulfide-Responsive Transcription Factor SqrR Regulates Gene Transfer and Biofilm Formation via the Metabolic Modulation of Cyclic di-GMP in Rhodobacter capsulatus.}, journal = {Microorganisms}, volume = {10}, number = {5}, pages = {}, pmid = {35630353}, issn = {2076-2607}, support = {JP18H03941//Japan Society for the Promotion of Science/ ; JP19H03241//Japan Society for the Promotion of Science/ ; JP20K06681//Japan Society for the Promotion of Science/ ; JP21K15038//Japan Society for the Promotion of Science/ ; JP21H05271//Japan Society for the Promotion of Science/ ; 20B004//Kurita Water and Environment Foundation/ ; 21K001//Kurita Water and Environment Foundation/ ; G-2019-2-010//Institute for Fermentation/ ; RGPIN 2018-03898//Natural Sciences and Engineering Research Council/ ; }, abstract = {Bacterial phage-like particles (gene transfer agents-GTAs) are widely employed as a crucial genetic vector in horizontal gene transfer. GTA-mediated gene transfer is induced in response to various stresses; however, regulatory mechanisms are poorly understood. We found that the persulfide-responsive transcription factor SqrR may repress the expression of several GTA-related genes in the photosynthetic bacterium Rhodobacter capsulatus. Here, we show that the sqrR deletion mutant (ΔsqrR) produces higher amounts of intra- and extracellular GTA and gene transfer activity than the wild type (WT). The transcript levels of GTA-related genes are also increased in ΔsqrR. In spite of the presumption that GTA-related genes are regulated in response to sulfide by SqrR, treatment with sulfide did not alter the transcript levels of these genes in the WT strain. Surprisingly, hydrogen peroxide increased the transcript levels of GTA-related genes in the WT, and this alteration was abolished in the ΔsqrR strain. Moreover, the absence of SqrR changed the intracellular cyclic dimeric GMP (c-di-GMP) levels, and the amount of c-di-GMP was correlated with GTA activity and biofilm formation. These results suggest that SqrR is related to the repression of GTA production and the activation of biofilm formation via control of the intracellular c-di-GMP levels.}, } @article {pmid35630332, year = {2022}, author = {Artini, M and Papa, R and Sapienza, F and Božović, M and Vrenna, G and Tuccio Guarna Assanti, V and Sabatino, M and Garzoli, S and Fiscarelli, EV and Ragno, R and Selan, L}, title = {Essential Oils Biofilm Modulation Activity and Machine Learning Analysis on Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients.}, journal = {Microorganisms}, volume = {10}, number = {5}, pages = {}, pmid = {35630332}, issn = {2076-2607}, support = {RM118164361B425B//Sapienza University Rome/ ; RM11916B8876093E//Sapienza University Rome/ ; RM120172B8EB30C5//Sapienza University Rome/ ; RM12117A89F5B8BB//Sapienza University Rome/ ; RP120172A3B0262B//Sapienza University Rome/ ; AR12117A62B1D411//Sapienza University Rome/ ; }, abstract = {The opportunistic pathogen Pseudomonas aeruginosa is often involved in airway infections of cystic fibrosis (CF) patients. It persists in the hostile CF lung environment, inducing chronic infections due to the production of several virulence factors. In this regard, the ability to form a biofilm plays a pivotal role in CF airway colonization by P. aeruginosa. Bacterial virulence mitigation and bacterial cell adhesion hampering and/or biofilm reduced formation could represent a major target for the development of new therapeutic treatments for infection control. Essential oils (EOs) are being considered as a potential alternative in clinical settings for the prevention, treatment, and control of infections sustained by microbial biofilms. EOs are complex mixtures of different classes of organic compounds, usually used for the treatment of upper respiratory tract infections in traditional medicine. Recently, a wide series of EOs were investigated for their ability to modulate biofilm production by different pathogens comprising S. aureus, S. epidermidis, and P. aeruginosa strains. Machine learning (ML) algorithms were applied to develop classification models in order to suggest a possible antibiofilm action for each chemical component of the studied EOs. In the present study, we assessed the biofilm growth modulation exerted by 61 commercial EOs on a selected number of P. aeruginosa strains isolated from CF patients. Furthermore, ML has been used to shed light on the EO chemical components likely responsible for the positive or negative modulation of bacterial biofilm formation.}, } @article {pmid35629935, year = {2022}, author = {Fitzgerald, S and Furlong, C and Holland, L and Morrin, A}, title = {Multi-Strain and -Species Investigation of Volatile Metabolites Emitted from Planktonic and Biofilm Candida Cultures.}, journal = {Metabolites}, volume = {12}, number = {5}, pages = {}, pmid = {35629935}, issn = {2218-1989}, support = {SFI/12/RC/2289_P2/SFI_/Science Foundation Ireland/Ireland ; }, abstract = {Candida parapsiliosis is a prevalent neonatal pathogen that attains its virulence through its strain-specific ability to form biofilms. The use of volatilomics, the profiling of volatile metabolites from microbes is a non-invasive, simple way to identify and classify microbes; it has shown great potential for pathogen identification. Although C. parapsiliosis is one of the most common clinical fungal pathogens, its volatilome has never been characterised. In this study, planktonic volatilomes of ten clinical strains of C. parapsilosis were analysed, along with a single strain of Candida albicans. Headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry were employed to analyse the samples. Species-, strain-, and media- influences on the fungal volatilomes were investigated. Twenty-four unique metabolites from the examined Candida spp. (22 from C. albicans; 18 from C. parapsilosis) were included in this study. Chemical classes detected across the samples included alcohols, fatty acid esters, acetates, thiols, sesquiterpenes, and nitrogen-containing compounds. C. albicans volatilomes were most clearly discriminated from C. parapsilosis based on the detection of unique sesquiterpene compounds. The effect of biofilm formation on the C. parapsilosis volatilomes was investigated for the first time by comparing volatilomes of a biofilm-positive strain and a biofilm-negative strain over time (0-48 h) using a novel sampling approach. Volatilomic shifts in the profiles of alcohols, ketones, acids, and acetates were observed specifically in the biofilm-forming samples and attributed to biofilm maturation. This study highlights species-specificity of Candida volatilomes, and also marks the clinical potential for volatilomics for non-invasively detecting fungal pathogens. Additionally, the range of biofilm-specificity across microbial volatilomes is potentially far-reaching, and therefore characterising these volatilomic changes in pathogenic fungal and bacterial biofilms could lead to novel opportunities for detecting severe infections early.}, } @article {pmid35629533, year = {2022}, author = {Khan, AS and Alshaia, A and AlDubayan, A and Alarifi, S and Alamri, A and Aldossary, H and Ahmed, SZ and Ateeq, IS and Hakeem, AS and Rehman, S}, title = {Preparation of Nano-Apatite Grafted Glass-Fiber-Reinforced Composites for Orthodontic Application: Mechanical and In Vitro Biofilm Analysis.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {10}, pages = {}, pmid = {35629533}, issn = {1996-1944}, abstract = {This study aimed to fabricate nano-hydroxyapatite (nHA) grafted/non-grafted E-glass-fiber-based (nHA/EG) and E-glass fiber (EG) orthodontic retainers and to compare their properties with commercially available retainers. Stainless-steel (SS) retainers and everStick Ortho (EST) were used as control groups. The retainers were evaluated with Raman spectroscopy and bonded to bovine teeth. The samples were fatigued under cyclic loading (120,000 cycles) followed by static load testing. The failure behavior was evaluated under an optical microscope and scanning electron microscope. The strain growth on the orthodontic retainers was assessed (48h and 168h) by an adhesion test using Staphylococcus aureus and Candida albicans. The characteristic peaks of resin and glass fibers were observed, and the debonding force results showed a significant difference among all of the groups. SS retainers showed the highest bonding force, whereas nHA/EG retainers showed a non-significant difference from EG and EST retainers. SS retainers' failure mode occurred mainly at the retainer-composite interface, while breakage occurred in glass-fiber-based retainers. The strains' adhesion to EST and EG was reduced with time. However, it was increased with nHA/EG. Fabrication of nHA/EG retainers was successfully achieved and showed better debonding force compared to other glass-fiber-based groups, whereas non-linear behavior was observed for the strains' adhesion.}, } @article {pmid35627712, year = {2022}, author = {Piletić, K and Kovač, B and Perčić, M and Žigon, J and Broznić, D and Karleuša, L and Lučić Blagojević, S and Oder, M and Gobin, I}, title = {Disinfecting Action of Gaseous Ozone on OXA-48-Producing Klebsiella pneumoniae Biofilm In Vitro.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {10}, pages = {}, pmid = {35627712}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Disinfectants/pharmacology ; Klebsiella pneumoniae ; *Ozone/pharmacology ; }, abstract = {Klebsiella pneumoniae is an emerging multidrug-resistant pathogen that can contaminate hospital surfaces in the form of a biofilm which is hard to remove with standard disinfectants. Because of biofilm resistance to conservative disinfectants, the application of new disinfection technologies is becoming more frequent. Ozone gas has antimicrobial activity but there is lack of data on its action against K. pneumoniae biofilm. The aim of this study was to investigate the effects and mechanisms of action of gaseous ozone on the OXA-48-procuding K. pneumoniae biofilm. A 24 h biofilm of K. pneumoniae formed on ceramic tiles was subsequently exposed to different concentrations of ozone during one and two hours to determine the optimal ozone concentration. Afterwards, the total bacteria count, total biomass and oxidative stress levels were monitored. A total of 25 ppm of gaseous ozone was determined to be optimal ozone concentration and caused reduction in total bacteria number in all strains of K. pneumoniae for 2.0 log10 CFU/cm[2], followed by reduction in total biomass up to 88.15%. Reactive oxygen species levels significantly increased after the ozone treatment at 182% for the representative K. pneumoniae NCTC 13442 strain. Ozone gas in the concentration of 25 ppm caused significant biofilm reduction but did not completely eradicate the K. pneumoniae biofilm formed on ceramics. In conclusion, ozone gas has great potential to be used as an additional hygiene measure in joint combat against biofilm in hospital environments.}, } @article {pmid35627252, year = {2022}, author = {Shao, Y and Yin, C and Lv, F and Jiang, S and Wu, S and Han, Y and Xue, W and Ma, Y and Zheng, J and Zhan, Y and Ke, X and Lu, W and Lin, M and Shang, L and Yan, Y}, title = {The Sigma Factor AlgU Regulates Exopolysaccharide Production and Nitrogen-Fixing Biofilm Formation by Directly Activating the Transcription of pslA in Pseudomonas stutzeri A1501.}, journal = {Genes}, volume = {13}, number = {5}, pages = {}, pmid = {35627252}, issn = {2073-4425}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Nitrogen/metabolism ; Nitrogenase/genetics/metabolism ; *Pseudomonas stutzeri/genetics/metabolism ; *Sigma Factor/genetics/metabolism ; }, abstract = {Pseudomonas stutzeri A1501, a plant-associated diazotrophic bacterium, prefers to conform to a nitrogen-fixing biofilm state under nitrogen-deficient conditions. The extracytoplasmic function (ECF) sigma factor AlgU is reported to play key roles in exopolysaccharide (EPS) production and biofilm formation in the Pseudomonas genus; however, the function of AlgU in P. stutzeri A1501 is still unclear. In this work, we mainly investigated the role of algU in EPS production, biofilm formation and nitrogenase activity in A1501. The algU mutant ΔalgU showed a dramatic decrease both in the EPS production and the biofilm formation capabilities. In addition, the biofilm-based nitrogenase activity was reduced by 81.4% in the ΔalgU mutant. The transcriptional level of pslA, a key Psl-like (a major EPS in A1501) synthesis-related gene, was almost completely inhibited in the algU mutant and was upregulated by 2.8-fold in the algU-overexpressing strain. A predicted AlgU-binding site was identified in the promoter region of pslA. The DNase I footprinting assays indicated that AlgU could directly bind to the pslA promoter, and β-galactosidase activity analysis further revealed mutations of the AlgU-binding boxes drastically reduced the transcriptional activity of the pslA promoter; moreover, we also demonstrated that AlgU was positively regulated by RpoN at the transcriptional level and negatively regulated by the RNA-binding protein RsmA at the posttranscriptional level. Taken together, these data suggest that AlgU promotes EPS production and nitrogen-fixing biofilm formation by directly activating the transcription of pslA, and the expression of AlgU is controlled by RpoN and RsmA at different regulatory levels.}, } @article {pmid35627021, year = {2022}, author = {Zhang, L and Meng, Y and Li, J and Yu, J and Mu, G and Tuo, Y}, title = {Lactiplantibacillus plantarum Y42 in Biofilm and Planktonic States Improves Intestinal Barrier Integrity and Modulates Gut Microbiota of Balb/c Mice.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {35627021}, issn = {2304-8158}, support = {32072193//National Natural Science Foundation of China/ ; }, abstract = {In our previous study, Lactiplantibacillus plantarum Y42 showed some potential probiotic functions and the ability to form biofilm. The aim of this study was to compare the similarities and differences in the probiotic and physiological traits of L. plantarum Y42 in the biofilm and planktonic states. L. plantarum Y42 in the biofilm state was proven to have higher survival after passing through mimic gastrointestinal fluid, as well as excellent adhesion properties on the HT-29 cell monolayers, than those in the planktonic state. The expression of tight junction proteins (TJ proteins) of HT-29 cell monolayers treated by L. plantarum Y42 in the planktonic state increased, while similar changes were not observed in the HT-29 cells treated by the strain in the biofilm state. Furthermore, Balb/c mice were orally administered L. plantarum Y42 in the biofilm and planktonic states, respectively. Compared to the planktonic state, the oral administration of L. plantarum Y42 in the biofilm state significantly boosted IgA levels and improved the immunity of the mice. High-throughput sequencing showed that the diversity and structure of the intestinal flora of the mice were changed after the oral administration of L. plantarum Y42, including the up-regulated relative abundance of Lactobacillus in the intestinal tract of the mice, with no difference between the biofilm and planktonic states. Moreover, oral administration of L. plantarum Y42 in biofilm and planktonic states reduced the release of proinflammatory factors, to a certain extent, in the serum of the mice. The similarities and differences in the probiotic and physiological properties of L. plantarum Y42 in the biofilm and planktonic states can be contributed to the reasonable application of the strain.}, } @article {pmid35625936, year = {2022}, author = {Wu, YF and Lin, YC and Yang, HW and Cheng, NC and Cheng, CM}, title = {Point-of-Care Wound Blotting with Alcian Blue Grading versus Fluorescence Imaging for Biofilm Detection and Predicting 90-Day Healing Outcomes.}, journal = {Biomedicines}, volume = {10}, number = {5}, pages = {}, pmid = {35625936}, issn = {2227-9059}, support = {110-BIH028//National Tsing Hua University-National Taiwan University BioMedical Park Hospital Collabora-tion Project/ ; 110-HCH073//National Tsing Hua University-National Taiwan University Hospital Hsin-Chu Branch Collaboration Project/ ; MOST 110-2222-E-002 -013-//Taiwan's Ministry of Science and Technology/ ; }, abstract = {Biofilm infection has been identified as a crucial factor of the pathogenesis of chronic wound, but wound biofilm diagnosis remains as an unmet clinical need. We previously proposed a modified wound blotting technique using Alcian blue staining for biofilm detection that was characterized as being non-invasive, time-saving, non-expansive, and informative for biofilm distribution. In this study, we adapted a novel Alcian blue grading method as the severity of biofilm infection for the wound blotting technique and compared its biofilm detection efficacy with MolecuLight i:X- a point-of-care florescence imaging device to detect bacteria and biofilm in wounds. Moreover, their predictive value of complete wound healing at 90 days was analyzed. When validated with wound culture results in the 53 enrolled subjects with chronic wounds, the modified wound blotting method showed a strong association with wound culture, while MolecuLight i:X only exhibited a weak association. In predicting 90-day wound outcomes, the modified wound blotting method showed a strong association (Kendall’s tau value = 0.563, p < 0.001), and the wound culture showed a moderate association (Spearman’s rho = 0.535, p < 0.001), but MolecuLight i:X exhibited no significant association (p = 0.184). In this study, modified wound blotting with the Alcian blue grading method showed superior value to MolecuLight i:X both in biofilm detection and predictive validity in 90-day wound-healing outcomes.}, } @article {pmid35625693, year = {2022}, author = {Solarte, DLG and Rau, SJ and Hellwig, E and Vach, K and Al-Ahmad, A}, title = {Antimicrobial Behavior and Cytotoxicity of Indocyanine Green in Combination with Visible Light and Water-Filtered Infrared A Radiation against Periodontal Bacteria and Subgingival Biofilm.}, journal = {Biomedicines}, volume = {10}, number = {5}, pages = {}, pmid = {35625693}, issn = {2227-9059}, support = {ICG//Dr. Braun Science Foundation/ ; AL 1179/4-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The widespread increase of antibiotic resistance highlights the need for alternative treatments such as antimicrobial photodynamic therapy (aPDT). This study aimed to evaluate the antimicrobial behavior and cytotoxicity of aPDT with indocyanine green (ICG) in combination with visible light (Vis) and water-filtered infrared A (wIRA). Representative periodontal bacteria (Parvimonas micra, Atopobium riame, Slackia exigua, Actinomyces naeslundii, Porphyromonas gingivalis, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Prevotella nigrescens) and subgingival in situ biofilms from periodontal patients were treated with aPDT for 5 min. ICG was used at different concentrations (50-500 µg/mL) and the number of viable cells was determined in colony forming units (CFU). Untreated negative controls and 0.2% chlorhexidine as a positive control were also prepared. The cytotoxicity test on human keratinocytes in vitro was analyzed with the AlamarBlue assay after 5, 10, and 20 min, with four ICG concentrations, and at two temperatures (room temperature and 37 °C). The tested periodontal pathogens treated with aPDT were eliminated in a range between 1.2 and 6.7 log10 CFU, except for A. naeslundii, which was killed at a lower range. The subgingival biofilm treated with aPDT expressed significant differences to the untreated controls except for at 300 µg/mL ICG concentration. The cytotoxicity was directly related to the concentration of ICG and irradiation time. These observations raise questions concerning the use of this specific aPDT as an adjuvant to periodontal treatments due to its possible toxicity towards human gingival cells.}, } @article {pmid35625332, year = {2022}, author = {Auer, DL and Mao, X and Anderson, AC and Muehler, D and Wittmer, A and von Ohle, C and Wolff, D and Frese, C and Hiller, KA and Maisch, T and Buchalla, W and Hellwig, E and Al-Ahmad, A and Cieplik, F}, title = {Phenotypic Adaptation to Antiseptics and Effects on Biofilm Formation Capacity and Antibiotic Resistance in Clinical Isolates of Early Colonizers in Dental Plaque.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625332}, issn = {2079-6382}, support = {CI 263/3-1//Deutsche Forschungsgemeinschaft/ ; AL 1179/4-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Despite the wide-spread use of antiseptics in dental practice and oral care products, there is little public awareness of potential risks associated with antiseptic resistance and potentially concomitant cross-resistance. Therefore, the aim of this study was to investigate potential phenotypic adaptation in 177 clinical isolates of early colonizers of dental plaque (Streptococcus, Actinomyces, Rothia and Veillonella spp.) upon repeated exposure to subinhibitory concentrations of chlorhexidine digluconate (CHX) or cetylpyridinium chloride (CPC) over 10 passages using a modified microdilution method. Stability of phenotypic adaptation was re-evaluated after culture in antiseptic-free nutrient broth for 24 or 72 h. Strains showing 8-fold minimal inhibitory concentration (MIC)-increase were further examined regarding their biofilm formation capacity, phenotypic antibiotic resistance and presence of antibiotic resistance genes (ARGs). Eight-fold MIC-increases to CHX were detected in four Streptococcus isolates. These strains mostly exhibited significantly increased biofilm formation capacity compared to their respective wild-type strains. Phenotypic antibiotic resistance was detected to tetracycline and erythromycin, consistent with the detected ARGs. In conclusion, this study shows that clinical isolates of early colonizers of dental plaque can phenotypically adapt toward antiseptics such as CHX upon repeated exposure. The underlying mechanisms at genomic and transcriptomic levels need to be investigated in future studies.}, } @article {pmid35625312, year = {2022}, author = {Mostafa, EM and Abdelgawad, MA and Musa, A and Alotaibi, NH and Elkomy, MH and Ghoneim, MM and Badawy, MSEM and Taha, MN and Hassan, HM and Hamed, AA}, title = {Chitosan Silver and Gold Nanoparticle Formation Using Endophytic Fungi as Powerful Antimicrobial and Anti-Biofilm Potentialities.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625312}, issn = {2079-6382}, abstract = {Nanotechnology is emerging as a new technology with encouraging innovations. Global antibiotic use has grown enormously, with antibiotic resistance increasing by about 80 percent. In view of this alarming situation, intensive research has been carried out into biogenic nanoparticles and their antibacterial, antifungal, and antitumor activities. Many methods are available to enhance stability and dispersion via peroration of conjugate with a polymer, such as chitosan, and other bioactive natural products. Two marine fungi were isolated and identified as Aspergillus sp. and Alternaria sp. via sequencing of the 16S rRNA gene. In this work, these strains were used to form the conjugation of biogenic silver nanoparticles (AgNPs) from Aspergillus sp. Silv2 extract and gold nanoparticles (AuNPs) from Alternaria sp. Gol2 extracts with chitosan to prepare chitosan-AgNPs and chitosan-AuNP conjugates. A variety of imaging and analytical methods, such as UV-vis, X-ray powder diffraction (XRD), FTIR spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were utilized to characterize biogenic nanoparticles and conjugates. The biosynthesized Ag and Au nanoparticles along with the prepared conjugates were evaluated for their antimicrobial effects on Gram-negative and Gram-positive bacterial isolates, including Escherichia coli and Staphylococcus aureus. Both chitosan-AgNP and AuNP showed powerful antimicrobial activities compared to the control. On the other hand, chitosan-AgNP conjugation had better antibacterial ctivity than chitosan-AuNPs, which exhibited moderate activity against S. aureus and very low activity against E. coli. Furthermore, the antibiofilm potentials of the prepared conjugates were tested against four biofilm-forming bacteria, including P. aeruginosa, B. subtilis, E. coli, and S. aureus. The obtained results indicate that the chitosan-AgNP showed a promising anti-biofilm activities on all strains, especially S. aureus, while chitosan-AuNP conjugates showed moderate anti-biofilm against B. subtilis and weak activities against the other three strains. These results showed the superiority of chitosan-AgNP as a promising antibacterial as well as biofilm formation inhibitors.}, } @article {pmid35625268, year = {2022}, author = {Doan, TH and Bernet-Camard, MF and Hoÿs, S and Janoir, C and Péchiné, S}, title = {Impact of Subinhibitory Concentrations of Metronidazole on Morphology, Motility, Biofilm Formation and Colonization of Clostridioides difficile.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625268}, issn = {2079-6382}, abstract = {Clostridioides difficile infection (CDI) is the primary cause of health-care-associated infectious diarrhea. Treatment requires mostly specific antibiotics such as metronidazole (MTZ), vancomycin or fidaxomicin. However, approximately 20% of treated patients experience recurrences. Treatment with MTZ is complicated by reduced susceptibility to this molecule, which could result in high failure and recurrence rates. However, the mechanism remains unclear. In this study, we investigated the impact of subinhibitory concentrations of MTZ on morphology, motility, biofilm formation, bacterial adherence to the intestinal Caco-2/TC7 differentiated monolayers, and colonization in monoxenic and conventional mouse models of two C. difficile strains (VPI 10463 and CD17-146), showing different susceptibility profiles to MTZ. Our results revealed that in addition to the inhibition of motility and the downregulation of flagellar genes for both strains, sub-inhibitory concentrations of MTZ induced various in vitro phenotypes for the strain CD17-146 exhibiting a reduced susceptibility to this antibiotic: elongated morphology, enhanced biofilm production and increased adherence to Caco-2/TC7 cells. Weak doses of MTZ induced higher level of colonization in the conventional mouse model and a trend to thicker 3-D structures entrapping bacteria in monoxenic mouse model. Thus, sub-inhibitory concentrations of MTZ can have a wide range of physiological effects on bacteria, which may contribute to their persistence after treatment.}, } @article {pmid35625242, year = {2022}, author = {Kim, D and Kim, KY}, title = {Pectolinarin Inhibits the Bacterial Biofilm Formation and Thereby Reduces Bacterial Pathogenicity.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625242}, issn = {2079-6382}, support = {GRRC-kyunghee2020(B04)//Gyeonggi do Regionaol Research center/ ; }, abstract = {Bacterial biofilms are a growing problem as it is a major cause of nosocomial infection from urinary catheters to chronic tissue infections and provide resistance to a variety of antibiotics and the host's immune system. The effect of pectolinarin on the biofilm formation in Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Streptococcus mutans, Streptococcus sobrinus, Staphylococcus aureus, Pseudomonas aeruginosa, Cutibacterium acnes, and Porphyromonas gingivalis was studied in TSBg (tryptic soy broth supplemented with 1% glucose). Pectolinarin inhibited biofilm formation of E. faecalis (IC50 = 0.39 μg/mL), E. faecium (IC50 = 0.19 μg/mL), E. coli (IC50 = 0.25 μg/mL), S. mutans (IC50 = 1.2 μg/mL), S. sobrinus (IC50 = 1.4 μg/mL), S. aureus (IC50 = 0.39 μg/mL), P. aeruginosa (IC50 = 0.9 μg/mL), P. acnes (IC50 = 12.5 μg/mL), and P. gingivalis (IC50 = 9.0 μg/mL) without inhibiting the bacterial growth. Pectolinarin also showed increased susceptibility of antibacterial activity with commercially available antibiotics including ampicillin, vancomycin, streptomycin, and oxytetracyclin against E. faecalis and E. faecium. Finally, pectolinarin dose-dependently reduced the expression of genes including cytolysin genes (cylLS, cylR2 and cylM), quorum sensing (QS) genes (fsrB, fsrC, gelE, ebpA, ebpB, acm, scm and bps), and biofilm virulence genes (esp) of E. faecalis and E. faecium. Pectolinarin reduced the bacterial biofilm formation, activated the antibacterial susceptibility, and reduced the bacterial adherence. These results suggest that bacterial biofilm formation is a good target to develop the antibacterial agents against biofilm-related infections.}, } @article {pmid35625233, year = {2022}, author = {Portell-Buj, E and González-Criollo, C and López-Gavín, A and Fernández-Pittol, M and Busquets, MA and Estelrich, J and Garrigó, M and Rubio, M and Tudó, G and Gonzalez-Martin, J}, title = {Activity of Antibiotics and Potential Antibiofilm Agents against Biofilm-Producing Mycobacterium avium-intracellulare Complex Causing Chronic Pulmonary Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625233}, issn = {2079-6382}, support = {PI16/01047//Instituto de Salud Carlos III/ ; 201816-10//Fundació La Marató TV3/ ; 937-2019//Sociedad Española de Neumología y Cirugía Torácica/ ; }, abstract = {Nontuberculous mycobacteria (NTM) cause lung infections in patients with underlying pulmonary diseases (PD). The Mycobacteriumavium-intracellulare complex (MAC) is the most frequently involved NTM. The MAC-PD treatment is based on the administration of several antibiotics for long periods of time. Nonetheless, treatment outcomes remain very poor. Among the factors involved is the ability of MAC isolates to form biofilm. The aim of the study was to assess the in vitro activity of different antibiotics and potential antibiofilm agents (PAAs) against MAC biofilm. Four antibiotics and six PAAs, alone and/or in combination, were tested against planktonic forms of 11 MAC clinical isolates. Biofilm was produced after 4 weeks of incubation and analyzed with the crystal violet assay. The antibiotics and PAAs were tested by measuring the absorbance (minimum biofilm inhibition concentrations, MBICs) and by performing subcultures (minimum biofilm eradication concentrations, MBECs). The clarithromycin/amikacin and clarithromycin/ethambutol combinations were synergistic, decreasing the MBECs values compared to the individual antibiotics. The amikacin/moxifloxacin combination showed indifference. The MBIC values decreased significantly when PAAs were added to the antibiotic combinations. These results suggest that antibiotic combinations should be further studied to establish their antibiofilm activity. Moreover, PAAs could act against the biofilm matrix, facilitating the activity of antibiotics.}, } @article {pmid35625217, year = {2022}, author = {Ashrit, P and Sadanandan, B and Shetty, K and Vaniyamparambath, V}, title = {Polymicrobial Biofilm Dynamics of Multidrug-Resistant Candida albicans and Ampicillin-Resistant Escherichia coli and Antimicrobial Inhibition by Aqueous Garlic Extract.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625217}, issn = {2079-6382}, support = {SR/WOS-A/LS-481/2013 (G)//Department of Science and Technology/ ; }, abstract = {The polymicrobial biofilm of C. albicans with E. coli exhibits a dynamic interspecies interaction and is refractory to conventional antimicrobials. In this study, a high biofilm-forming multidrug-resistant strain of C. albicans overcomes inhibition by E. coli in a 24 h coculture. However, following treatment with whole Aqueous Garlic Extract (AGE), these individual biofilms of multidrug-resistant C. albicans M-207 and Ampicillin-resistant Escherichia coli ATCC 39936 and their polymicrobial biofilm were prevented, as evidenced by biochemical and structural characterization. This study advances the antimicrobial potential of AGE to inhibit drug-resistant C. albicans and bacterial-associated polymicrobial biofilms, suggesting the potential for effective combinatorial and synergistic antimicrobial designs with minimal side effects.}, } @article {pmid35625202, year = {2022}, author = {Castro, J and Sousa, LGV and França, Â and Podpera Tisakova, L and Corsini, L and Cerca, N}, title = {Exploiting the Anti-Biofilm Effect of the Engineered Phage Endolysin PM-477 to Disrupt In Vitro Single- and Dual-Species Biofilms of Vaginal Pathogens Associated with Bacterial Vaginosis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {5}, pages = {}, pmid = {35625202}, issn = {2079-6382}, support = {UIDB/04469/2020//Fundação para a Ciência e Tecnologia/ ; }, abstract = {Bacterial vaginosis (BV) is the most frequent vaginal infection in women of reproductive age. It is caused by the overgrowth of anaerobic vaginal pathogens, such as Gardnerella vaginalis, Fannyhessea vaginae, and Prevotella bivia, which are vaginal pathogens detected during the early stages of incident BV and have been found to form multi-species biofilms. Treatment of biofilm-associated infections, such as BV, is challenging. In this study, we tested the role of an investigational engineered phage endolysin, PM-477, in the eradication of dual-species biofilms composed of G. vaginalis-F. vaginae or G. vaginalis-P. bivia. Single-species biofilms formed by these species were also analysed as controls. The effect of PM-477 on biomass and culturability of single- and dual-species biofilms was assessed in vitro using a microtiter plate assay, epifluorescence microscopy, confocal laser scanning microscopy, and quantitative PCR. The results showed that PM-477 was particularly effective in the disruption and reduction of culturability of G. vaginalis biofilms. In dual-species biofilms, PM-477 exhibited lower efficiency but was still able to selectively and significantly eliminate G. vaginalis. Since polymicrobial interactions have been shown to strongly affect the activity of various antibiotics, the activity of PM-477 in dual-species biofilms is a potentially promising result that should be further explored, aiming to completely eradicate multi-species biofilms associated with BV.}, } @article {pmid35624548, year = {2022}, author = {Jyväsjärvi, J and Rajakallio, M and Brüsecke, J and Huttunen, KL and Huusko, A and Muotka, T and Taipale, SJ}, title = {Dark matters: Contrasting responses of stream biofilm to browning and loss of riparian shading.}, journal = {Global change biology}, volume = {28}, number = {17}, pages = {5159-5171}, pmid = {35624548}, issn = {1365-2486}, mesh = {Biofilms ; *Ecosystem ; Forests ; *Rivers ; Sterols ; }, abstract = {Concentrations of terrestrial-derived dissolved organic carbon (DOC) in freshwater ecosystems have increased consistently, causing freshwater browning. The mechanisms behind browning are complex, but in forestry-intensive regions browning is accelerated by land drainage. Forestry actions in streamside riparian forests alter canopy shading, which together with browning is expected to exert a complex and largely unpredictable control over key ecosystem functions. We conducted a stream mesocosm experiment with three levels of browning (ambient vs. moderate vs. high, with 2.7 and 5.5-fold increase, respectively, in absorbance) crossed with two levels of riparian shading (70% light reduction vs. open canopy) to explore the individual and combined effects of browning and loss of shading on the quantity (algal biomass) and nutritional quality (polyunsaturated fatty acid and sterol content) of the periphytic biofilm. We also conducted a field survey of differently colored (4.7 to 26.2 mg DOC L[-1]) streams to provide a 'reality check' for our experimental findings. Browning reduced greatly the algal biomass, suppressed the availability of essential polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA), and sterols, but increased the availability of terrestrial-derived long-chain saturated fatty acids (LSAFA). In contrast, loss of shading increased primary productivity, which resulted in elevated sterol and EPA contents of the biofilm. The field survey largely repeated the same pattern: biofilm nutritional quality decreased significantly with increasing DOC, as indicated particularly by a decrease of the ω-3:ω-6 ratio and increase in LSAFA content. Algal biomass, in contrast, was mainly controlled by dissolved inorganic nitrogen (DIN) concentration, while DOC concentration was of minor importance. The ongoing browning process is inducing a dramatic reduction in the nutritional quality of the stream biofilm. Such degradation of the major high-quality food source available for stream consumers may reduce the trophic transfer efficiency in stream ecosystems, potentially extending across the stream-forest ecotone.}, } @article {pmid35623782, year = {2022}, author = {Caniglia, G and Sportelli, MC and Heinzmann, A and Picca, RA and Valentini, A and Barth, H and Mizaikoff, B and Cioffi, N and Kranz, C}, title = {Silver-fluoropolymer (Ag-CFX) films: Kinetic study of silver release, and spectroscopic-microscopic insight into the inhibition of P. fluorescens biofilm formation.}, journal = {Analytica chimica acta}, volume = {1212}, number = {}, pages = {339892}, doi = {10.1016/j.aca.2022.339892}, pmid = {35623782}, issn = {1873-4324}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/pharmacology ; Bacteria ; Biofilms ; *Metal Nanoparticles/chemistry ; Silver/chemistry ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Silver-fluoropolymer (Ag-CFX) composed of encapsulated bioactive nanophases within a thin polymer coating are promising antimicrobial films with excellent bioactivity. In this contribution, we report on Ag-CFX thin films obtained by ion beam co-sputtering, accurately tuning film thickness, and inorganic loading. The Ag-CFX films were characterized by spectroscopic and scanning probe microscopy techniques with respect to composition and swelling behavior. Next to electrothermal atomic absorption spectroscopy (ETAAS) studies, scanning electrochemical microscopy (SECM) experiments in combination with anodic stripping voltammetry (ASV) were carried out to study the release mechanism of silver(I) from the embedded silver nanoparticles (AgNPs). Silver(I) concentration profiles at the Ag-CFX films in contact with water resulted in a release of 1310 ± 50 μg L[-1] (n = 3) after 27 h of immersion and corresponded well to the swelling of the films. The antimicrobial properties towards biofilm formation of P. fluorescens were studied by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy during a period of 48 h. The obtained IR data revealed biofilm inhibition due to the presence of the antimicrobial layer but also indicated potential surface re-colonization after 30 h of contact with the bacteria-containing solution. The occurrence of cyclic changes in the characteristic IR bands correlated with apparent stress of bottom-layered bacteria, along with re-colonization on top of dead biomass, indicative of potential cannibalism events.}, } @article {pmid35623775, year = {2022}, author = {Ge, Y and Ge, Z and Zheng, J and Sheng, X and He, L}, title = {Biofilm-overproducing Bacillus subtilis B12ΔYwcc decreases Cd uptake in Chinese cabbage through increasing Cd-immobilizing related gene abundance and root surface colonization.}, journal = {Journal of environmental sciences (China)}, volume = {120}, number = {}, pages = {84-93}, doi = {10.1016/j.jes.2022.01.016}, pmid = {35623775}, issn = {1001-0742}, mesh = {Bacillus subtilis/genetics ; Biofilms ; *Brassica ; Cadmium/analysis/toxicity ; China ; Polysaccharides ; Soil ; *Soil Pollutants/analysis ; Vegetables ; }, abstract = {Biofilm-producing bacteria can decrease Cd uptake in vegetables, but mechanisms underlying this effect are poorly characterized. In this study, two mutant strains B12ΔYwcc and B12ΔSlrR were constructed from a biofilm-producing Bacillus subtilis strain B12. Then, the impacts of strain B12 and its high biofilm-producing mutant strain B12ΔYwcc and low biofilm-producing mutant strain B12ΔSlrR on Cd availability and uptake in Chinese cabbage and the related mechanisms were investigated in the Cd-polluted soil. Strain B12 and its mutants B12ΔYwcc and B12ΔSlrR increased the dry biomasses of edible tissues by 54%-130% compared with the controls. Strain B12 and its mutant B12ΔYwcc reduced the soil available Cd content by 36%-50% and root and edible tissue Cd contents by 23%-50% compared with the controls. Furthermore, the mutant strain B12ΔYwcc reduced the edible tissue Cd content by 40% and increased the polysaccharide content by 23%, invertase activity by 139%, and gene copies of the cumA by 4.5-fold, epsA by 7.1-fold, and cadA by 4.3-fold, which were involved in Cd adsorption in the rhizosphere soils, respectively, compared with strain B12. The polysaccharide content and cumA, epsA, and cadA gene copy numbers showed significantly reverse correlations with the available Cd content. Notably, the mutant strain B12ΔYwcc showed better ability to colonize the vegetable root surface than strain B12. These findings demonstrated that the biofilm-overproducing mutant strain B12ΔYwcc increased the polysaccharide production and Cd-immobilizing related cumA, epsA, and cadA gene copies, resulting in lower Cd availability and accumulation in Chinese cabbage in the Cd-polluted soil.}, } @article {pmid35623607, year = {2022}, author = {Wang, C and Lin, Q and Yao, Y and Xu, R and Wu, X and Meng, F}, title = {Achieving simultaneous nitrification, denitrification, and phosphorus removal in pilot-scale flow-through biofilm reactor with low dissolved oxygen concentrations: Performance and mechanisms.}, journal = {Bioresource technology}, volume = {358}, number = {}, pages = {127373}, doi = {10.1016/j.biortech.2022.127373}, pmid = {35623607}, issn = {1873-2976}, mesh = {Bacteria ; Biofilms ; Bioreactors/microbiology ; Denitrification ; *Nitrification ; Nitrogen ; Oxygen ; *Phosphorus ; Sewage/microbiology ; Wastewater/microbiology ; }, abstract = {In this pilot-scale study, a flow-through biofilm reactor (FTBR) was investigated for municipal wastewater treatment. The removal efficiencies for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand were 87.2 ± 17.9%, 61.1 ± 13.9%, 83.5 ± 11.9%, and 92.6 ± 1.7%, respectively, at low dissolved oxygen concentrations (averaged at 0.59 mg/L), indicating the feasibility and robustness of the FTBR for a simultaneous nitrification, denitrification, and phosphorous removal (SNDPR) process. The co-occurrence network of bacteria in the dynamic biofilm was complex, with equivalent bacterial cooperation and competition. Nevertheless, the bacterial interactions in the suspended sludge were mainly cooperative. The presence of dynamic biofilms increased bacterial diversity by creating niche differentiation, which enriched keystone species closely related to nutrient removal. Overall, this study provides a novel FTBR-based SNDPR process and reveals the ecological mechanisms responsible for nutrient removal.}, } @article {pmid35623093, year = {2022}, author = {Li, W and Siddique, MS and Graham, N and Yu, W}, title = {Influence of Temperature on Biofilm Formation Mechanisms Using a Gravity-Driven Membrane (GDM) System: Insights from Microbial Community Structures and Metabolomics.}, journal = {Environmental science & technology}, volume = {56}, number = {12}, pages = {8908-8919}, doi = {10.1021/acs.est.2c01243}, pmid = {35623093}, issn = {1520-5851}, mesh = {Biofilms ; *Membranes, Artificial ; Metabolomics ; *Microbiota ; Pyrimidines ; Temperature ; }, abstract = {A biofilm has a significant effect on water treatment processes. Currently, there is a lack of knowledge about the effect of temperature on the biofilm structure in water treatment processes. In this study, a gravity-driven membrane ultrafiltration system was operated with river feedwater at two temperatures ("low", 4 °C; "high", 25 °C) to explore the biofilm structure and transformation mechanism. The results showed that the difference in dissolved oxygen concentration might be one of the main factors regulating the structural components of the biofilm. A denser biofilm formation and reduced flux were observed at the lower temperature. The linoleic acid metabolism was significantly inhibited at low temperature, resulting in enhanced pyrimidine metabolism by Na[+] accumulation. In addition, the biofilm at low temperature had a higher proportion of the metabolites of lipids and lipid-like molecules (11.25%), organic acids and derivatives (10.83%), nucleosides, nucleotides, and analogues (7.083%), and organoheterocyclic compounds (6.66%). These small molecules secrete more polysaccharides having C═O and O═C-O functional groups, which intensified the resistance of the biofilm. Furthermore, the upregulation pathway of pyrimidine metabolism also increased the risk of urea accumulation at low temperature. Limnohabitans, Deinococcus, Diaphorobacter, Flavobacterium, and Pseudomonas were identified as the principal microorganisms involved in this metabolic transformation.}, } @article {pmid35622767, year = {2022}, author = {Mahmoud, SF and Fayez, M and Swelum, AA and Alswat, AS and Alkafafy, M and Alzahrani, OM and Alsunaini, SJ and Almuslem, A and Al Amer, AS and Yusuf, S}, title = {Genetic Diversity, Biofilm Formation, and Antibiotic Resistance of Pseudomonas aeruginosa Isolated from Cow, Camel, and Mare with Clinical Endometritis.}, journal = {Veterinary sciences}, volume = {9}, number = {5}, pages = {}, pmid = {35622767}, issn = {2306-7381}, support = {Taif University Researchers Supporting Project number (TURSP-2020/138), Taif University, PO Box 11099, Taif 21944, Saudi Arabia.//Taif University/ ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous opportunistic bacterium that causes diseases in animals and humans. This study aimed to investigate the genetic diversity, antimicrobial resistance, biofilm formation, and virulence and antibiotic resistance genes of P. aeruginosa isolated from the uterus of cow, camel, and mare with clinical endometritis and their drinking water. Among the 180 uterine swabs and 90 drinking water samples analysed, 54 (20%) P. aeruginosa isolates were recovered. Isolates were identified biochemically to the genus level by the automated Vitek 2 system and genetically by the amplification of the gyrB gene and the sequencing of the 16S rRNA gene. Multilocus sequence typing identified ten different sequence types for the P. aeruginosa isolates. The identification of ST2012 was significantly (p ≤ 0.05) higher than that of ST296, ST308, ST111, and ST241. The isolates exhibited significantly (p ≤ 0.05) increased resistance to piperacillin (77.8%), ciprofloxacin (59.3%), gentamicin (50%), and ceftazidime (38.9%). Eight (14.8%) isolates showed resistance to imipenem; however, none of the isolates showed resistance to colistin. Multidrug resistance (MDR) was observed in 24 isolates (44.4%) with a multiple antibiotic resistance index ranging from 0.44 to 0.77. MDR was identified in 30 (33.3%) isolates. Furthermore, 38.8% and 9.2% of the isolates exhibited a positive extended-spectrum-β-lactamase (ESBL) and metallo-β-lactamase (MBL) phenotype, respectively. The most prevalent β-lactamase encoding genes were blaTEM and blaCTX-M, however, the blaIPM gene was not detected in any of the isolates. Biofilm formation was observed in 49 (90.7%) isolates classified as: 11.1% weak biofilm producers; 38.9% moderate biofilm producers; 40.7% strong biofilm producers. A positive correlation was observed between the MAR index and biofilm formation. In conclusion, the results highlighted that farm animals with clinical endometritis could act as a reservoir for MDR and virulent P. aeruginosa. The emergence of ESBLs and MBLs producing P. aeruginosa in different farm animals is a public health concern. Therefore, surveillance programs to monitor and control MDR P. aeruginosa in animals are required.}, } @article {pmid35622167, year = {2022}, author = {Keymaram, M and Falahati, M and Farahyar, S and Lotfali, E and Abolghasemi, S and Mahmoudi, S and Sadeghi, F and Khalandi, H and Ghasemi, R and Shamsaei, S and Raiesi, O}, title = {Correction to: Anti-biofilm properties of eucalyptol in combination with antifungals against Candida albicans isolates in patients with hematological malignancy.}, journal = {Archives of microbiology}, volume = {204}, number = {6}, pages = {351}, doi = {10.1007/s00203-022-03019-0}, pmid = {35622167}, issn = {1432-072X}, } @article {pmid35621538, year = {2022}, author = {Xu, CP and Palazzolo, DL and Cuadra, GA}, title = {Mechanistic Effects of E-Liquids on Biofilm Formation and Growth of Oral Commensal Streptococcal Communities: Effect of Flavoring Agents.}, journal = {Dentistry journal}, volume = {10}, number = {5}, pages = {}, pmid = {35621538}, issn = {2304-6767}, abstract = {Background: Vaping has become a global health concern. As research continues, more studies are beginning to question the relative safety of E-liquid flavoring additives. The oral cavity is the first site of exposure to E-liquid aerosol, making it critical for investigation. Because of the importance of commensal bacterial biofilms for oral health, we sought to explore the effects of E-liquids ± flavors on the formation and growth of single- and multi-species biofilms and to investigate the mechanism of inhibition. Methods: Quantitative and confocal biofilm analysis, death curves, and colony-forming units (CFU) were evaluated with flavorless and flavored (tobacco, menthol, cinnamon, strawberry, blueberry) E-liquids using four strains of oral commensal bacteria (Streptococcus gordonii, Streptococcus intermedius, Streptococcus mitis, and Streptococcus oralis). Results: All flavoring agents show a dose-dependent inhibition in the growth of single-species and multi-species biofilms. Furthermore, CFUs, death curves, and light microscopy show that flavoring agents have a bactericidal mode of inhibition on the growth of these oral streptococci. Conclusions: These results show that flavored, rather than unflavored, E-liquids are more detrimental to biofilm formation and growth of oral commensal bacteria. Consequently, E-liquid flavorings agents could pose risks to the oral microenvironment, and by extension, to systemic health.}, } @article {pmid35621500, year = {2022}, author = {Pang, S and Rittmann, BE and Wu, C and Yang, L and Zhou, J and Xia, S}, title = {Synergistic Inorganic Carbon and Denitrification Genes Contributed to Nitrite Accumulation in a Hydrogen-Based Membrane Biofilm Reactor.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {35621500}, issn = {2306-5354}, support = {2021YFC3201300//National Key Project of Research and Development Plan of China/ ; NSFC 51678422//National Natural Science Foundation of China/ ; }, abstract = {Partial denitrification, the termination of NO3[-]-N reduction at nitrite (NO2[-]-N), has received growing interest for treating wastewaters with high ammonium concentrations, because it can be coupled to anammox for total-nitrogen removal. NO2[-] accumulation in the hydrogen (H2)-based membrane biofilm reactor (MBfR) has rarely been studied, and the mechanisms behind its accumulation have not been defined. This study aimed at achieving the partial denitrification with H2-based autotrophic reducing bacteria in a MBfR. Results showed that by increasing the NO3[-] loading, increasing the pH, and decreasing the inorganic-carbon concentration, a nitrite transformation rate higher than 68% was achieved. Community analysis indicated that Thauera and Azoarcus became the dominant genera when partial denitrification was occurring. Functional genes abundances proved that partial denitrification to accumulate NO2[-] was correlated to increases of gene for the form I RuBisCo enzyme (cbbL). This study confirmed the feasibility of autotrophic partial denitrification formed in the MBfR, and revealed the inorganic carbon mechanism in MBfR denitrification.}, } @article {pmid35620882, year = {2022}, author = {Xu, L and Qin, X and Mozaffari, MS and Yan, D and Sun, X and Cao, Y}, title = {Hybrid system with stable structure of hard/soft tissue substitutes induces re-osseointegration in a rat model of biofilm-mediated peri-implantitis.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {110}, number = {11}, pages = {2452-2463}, doi = {10.1002/jbm.b.35102}, pmid = {35620882}, issn = {1552-4981}, support = {NZ17178//Natural Science Foundation of Ningxia Province/ ; 81700940//National Natural Science Foundation of China/ ; 81800981//National Natural Science Foundation of China/ ; 81860203//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Calcium Phosphates ; Cytokines ; *Dental Implants ; Interleukin-6 ; Osseointegration ; *Peri-Implantitis/pathology ; Rats ; Tetracycline/pharmacology ; }, abstract = {Re-osseointegration of an infected/contaminated dental implant poses major clinical challenges. We tested the hypothesis that the application of an antibiotic-releasing construct, combined with hard/soft tissue replacement, increases the efficacy of reconstructive therapy. We initially fabricated semi-flexible hybrid constructs of β-TCP/PHBHHx, with tetracycline (TC) (TC amounts: 5%, 10%, and 15%). Thereafter, using in vitro assays, TC release profile, attachment to rat bone marrow-derived stem cells (rBMSCs) and their viability as well as anti-bacterial activity were determined. Thereafter, regenerative efficacies of the three hybrid constructs were assessed in a rat model of peri-implantitis induced by Aggregatibacter actinomycetemcomitans biofilm; control animals received β-TCP/Bio-Gide and TC injection. Eight weeks later, maxillae were obtained for radiological, histological, and histomorphometric analyses of peri-implant tissues. Sulcus bleeding index was chronologically recorded. Serum cytokines levels of IL-6 and IL-1β were also evaluated by enzyme-linked immunosorbent assay. Substantial amounts of tetracycline, from hybrid constructs, were released for 2 weeks. The medium containing the released tetracycline did not affect the adhesion or viability of rBMSCs; however, it inhibited the proliferation of A. actinomycetemcomitans. Osteogenesis and osseointegration were more marked for the 15% hybrid construct group than the other two groups. The height of attachment and infiltration of inflammatory cells within fibrous tissue was significantly reduced in the experimental groups than the control group. Our protocol resulted in re-osseointegration on a biofilm-contaminated implant. Thus, an antibiotic releasing inorganic/organic construct may offer a therapeutic option to suppress infection and promote guided tissue regeneration thereby serving as an integrated multi-layer substitute for both hard/soft tissues.}, } @article {pmid35619831, year = {2022}, author = {Knoll, MT and Fuderer, E and Gescher, J}, title = {Sprayable biofilm - Agarose hydrogels as 3D matrix for enhanced productivity in bioelectrochemical systems.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100077}, pmid = {35619831}, issn = {2590-2075}, abstract = {Bio-based energy production utilizing renewable resources can be realized by exoelectrogenic organisms and their application in bioelectrochemical systems (BES). These organisms catalyze the direct conversion of chemical into electrical energy and are already widely used in bioelectronics and biosensing. However, the biofilm-electrode interaction is a factor that limits sufficient space-time-yields for industrial applications. In this study, a hydrogel matrix consisting of agarose fibers was utilized as a scaffold for S. oneidensis cells to improve anodic processes in BES. This synthetic, scalable biofilm reached a higher current density in BES in comparison to naturally formed biofilms. Complemented with carbon nanofibers and riboflavin, the application of this functionalized hydrogel containing S. oneidensis cells led to an overall 9.1-fold increase in current density to 1324 mA m[-2] in comparison to 145 mA m[-2] for the planktonic control. In addition, the synthetic biofilm can be applied by spraying onto surfaces using a novel spray applicator. The latter allows to apply the biofilm effortless on large surfaces which will facilitate scalability and thus industrial application.}, } @article {pmid35619261, year = {2022}, author = {Yadav, J and Das, S and Karthikeyan, D and Chug, R and Jyoti, A and Srivastava, VK and Jain, A and Kumar, S and Sharma, V and Kaushik, S}, title = {Identification of Protein Drug Targets of Biofilm Formation and Quorum Sensing in Multidrug Resistant Enterococcus faecalis.}, journal = {Current protein & peptide science}, volume = {23}, number = {4}, pages = {248-263}, doi = {10.2174/1389203723666220526155644}, pmid = {35619261}, issn = {1875-5550}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacterial Proteins/metabolism ; *Biofilms ; *Drug Resistance, Multiple, Bacterial ; *Enterococcus faecalis/drug effects ; *Quorum Sensing ; Virulence ; Virulence Factors/genetics ; }, abstract = {Enterococcus faecalis (E. faecalis) is an opportunistic multidrug-resistant (MDR) pathogen found in the guts of humans and farmed animals. Due to the occurrence of (MDR) strain there is an urgent need to look for an alternative treatment approach. E. faecalis is a Gram-positive bacterium, which is among the most prevalent multidrug resistant hospital pathogens. Its ability to develop quorum sensing (QS) mediated biofilm formation further exacerbates the pathogenicity and triggers lifethreatening infections. Therefore, developing a suitable remedy for curing E. faecalis mediated enterococcal infections is an arduous task. Several putative virulence factors and proteins are involved in the development of biofilms in E. faecalis. Such proteins often play important roles in virulence, disease, and colonization by pathogens. The elucidation of the structure-function relationship of such protein drug targets and the interacting compounds could provide an attractive paradigm towards developing structure-based drugs against E. faecalis. This review provides a comprehensive overview of the current status, enigmas that warrant further studies, and the prospects toward alleviating the antibiotic resistance in E. faecalis. Specifically, the role of biofilm and quorum sensing (QS) in the emergence of MDR strains had been elaborated along with the importance of the protein drug targets involved in both the processes.}, } @article {pmid35616791, year = {2022}, author = {Mamonova, IA and Babushkina, IV and Ulyanov, VY and Shpinyak, SP}, title = {Kinetics of the Growth of Enterococcus spp. Biofilm Formed by Strains Isolated from Patients with Infectious Complications after Large joint Replacements.}, journal = {Bulletin of experimental biology and medicine}, volume = {173}, number = {1}, pages = {63-66}, pmid = {35616791}, issn = {1573-8221}, mesh = {Anti-Bacterial Agents/metabolism ; *Arthroplasty, Replacement ; Biofilms ; Enterococcus/metabolism ; Enterococcus faecalis ; *Gram-Positive Bacterial Infections ; Humans ; Kinetics ; }, abstract = {We studied the kinetics of growth of biofilms and plankton forms of Enterococcus spp. strains isolated in implant-associated infection of large joints. The capacity for biofilm formation by enterococci was demonstrated. The following stages of biofilm formation were revealed: biofilm formation and maturation, its degradation, and secondary dissemination. These findings extend our understanding of the wound process caused by enterococci.}, } @article {pmid35616277, year = {2022}, author = {Ning, Y and Wang, X and Chen, P and Liu, S and Hu, J and Xiao, R and Li, L and Lu, F}, title = {Targeted inhibition of methicillin-resistant Staphylococcus aureus biofilm formation by a graphene oxide-loaded aptamer/berberine bifunctional complex.}, journal = {Drug delivery}, volume = {29}, number = {1}, pages = {1675-1683}, pmid = {35616277}, issn = {1521-0464}, mesh = {Anti-Bacterial Agents/metabolism ; *Berberine/pharmacology ; Biofilms ; Graphite ; Humans ; *Methicillin-Resistant Staphylococcus aureus/metabolism ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; }, abstract = {Biofilm formation is known to promote drug resistance in methicillin-resistant Staphylococcus aureus (MRSA), which is closely related to persistent infections in hospital settings. In this study, a DNA aptamer specific to penicillin-binding protein 2a (PBP2a) with a dissociation constant (Kd) of 82.97 ± 8.86 nM was obtained after 14 cycles of systematic evolution of ligands by exponential enrichment (SELEX). Next, a bifunctional complex containing the aptamer intercalated by berberine into the double-strand region was prepared and adsorbed onto the surface of graphene oxide (GO) by π-stacking interactions. The GO-loaded aptamer/berberine bifunctional complex showed significantly higher inhibition of MRSA biofilm formation than the control. Furthermore, this study shows that the complex possesses anti-biofilm activity, which can be attributed to the ability of the aptamer to reduce cell-surface attachment by blocking the function of PBP2a and berberine to attenuate the level of the accessory gene regulator (agr) system, which plays an important role in mediating MRSA biofilm formation. Therefore, the simultaneous delivery of berberine and PBP2a-targted aptamer using GO may have potential for the treatment of chronic infections caused by MRSA biofilms. It also provides a new avenue for multitarget treatment of bacterial biofilms.}, } @article {pmid35615510, year = {2022}, author = {Budroni, M and Torija, MJ and Moreno-García, J and Zara, G}, title = {Editorial: Biofilm and Food: Well- and Lesser-Known Interactions.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {923021}, doi = {10.3389/fmicb.2022.923021}, pmid = {35615510}, issn = {1664-302X}, } @article {pmid35614284, year = {2022}, author = {Dong, M and Yang, X and Liu, L and Zhou, Z and Deng, L and Zhong, Z and Liu, H and Ma, X and Fu, H and Cao, S and Shen, L and Peng, G}, title = {Role of Hfq in glucose utilization, biofilm formation and quorum sensing system in Bacillus subtilis.}, journal = {Biotechnology letters}, volume = {44}, number = {7}, pages = {845-855}, pmid = {35614284}, issn = {1573-6776}, support = {CPF2015-09//Chengdu Giant Panda Breeding Research Foundation/ ; CPF2017-12//Chengdu Giant Panda Breeding Research Foundation/ ; }, mesh = {*Bacillus subtilis/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Glucose/metabolism ; *Quorum Sensing/genetics ; }, abstract = {Hfq is an RNA-binding protein, its main function is to participate in post-transcriptional regulation of bacteria and regulate small regulatory RNA (sRNA) and messenger RNA (mRNA) stability, but the Hfq function of Bacillus subtilis (B. subtilis) has not been fully explained. In this study, we used the strains of B. subtilis168 (BS168), BS168Δhfq and BS168Δhfq-C to explore the effects of Hfq on the glucose utilization, biofilm formation and quorum sensing (QS) system of B. subtilis. The results showed that the knockout of hfq resulted in growth defects when bacteria were cultured in the Luria-Bertani (LB) medium, but we did not observe the same effects in Nitrogen medium (NM) and Inorganic Salt-free medium (ISM). We further found that the growth of strains under different glucose concentrations was also different, which was related to the expression of CcpA. Interestingly, the hfq mutant showed increased resistance to a high-glucose environment. Furthermore, the biofilm and extracellular poly saccharides (EPS) formation of BS168Δhfq decreased significantly. At the same time, changes were observed in the morphology of the biofilm, such as larger intercellular space of the biofilm and thinner edge. The qRT-PCR results confirmed that the hfq knockout caused significant up-regulation or down-regulation of gene expression in QS system, and down-regulated genes were involved in the positive regulation of biofilm formation. Taken together, we demonstrated that Hfq plays a vital role in glucose utilization, biofilm formation and QS of B. subtilis, which provides a new perspective for subsequent related research.}, } @article {pmid35614186, year = {2022}, author = {Ciecholewska-Juśko, D and Żywicka, A and Junka, A and Woroszyło, M and Wardach, M and Chodaczek, G and Szymczyk-Ziółkowska, P and Migdał, P and Fijałkowski, K}, title = {The effects of rotating magnetic field and antiseptic on in vitro pathogenic biofilm and its milieu.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {8836}, pmid = {35614186}, issn = {2045-2322}, mesh = {Agar/pharmacology ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; *Anti-Infective Agents, Local/pharmacology ; Biofilms ; Magnetic Fields ; Pseudomonas aeruginosa ; Staphylococcus aureus ; }, abstract = {The application of various magnetic fields for boosting the efficacy of different antimicrobial molecules or in the character of a self-reliant antimicrobial agent is considered a promising approach to eradicating bacterial biofilm-related infections. The purpose of this study was to analyze the phenomenon of increased activity of octenidine dihydrochloride-based antiseptic (OCT) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms in the presence of the rotating magnetic field (RMF) of two frequencies, 5 and 50 Hz, in the in vitro model consisting of stacked agar discs, placed in increasing distance from the source of the antiseptic solution. The biofilm-forming cells' viability and morphology as well as biofilm matrix structure and composition were analyzed. Also, octenidine dihydrochloride permeability through biofilm and porous agar obstacles was determined for the RMF-exposed versus unexposed settings. The exposure to RMF or OCT apart did not lead to biofilm destruction, contrary to the setting in which these two agents were used together. The performed analyses revealed the effect of RMF not only on biofilms (weakening of cell wall/membranes, disturbed morphology of cells, altered biofilm matrix porosity, and composition) but also on its milieu (altered penetrability of octenidine dihydrochloride through biofilm/agar obstacles). Our results suggest that the combination of RMF and OCT can be particularly promising in eradicating biofilms located in such areas as wound pockets, where physical obstacles limit antiseptic activity.}, } @article {pmid35613523, year = {2022}, author = {Guliy, OI and Evstigneeva, SS and Bunin, VD}, title = {Microfluidic bioanalytical system for biofilm formation indication.}, journal = {Talanta}, volume = {247}, number = {}, pages = {123541}, doi = {10.1016/j.talanta.2022.123541}, pmid = {35613523}, issn = {1873-3573}, mesh = {Bacteria ; *Biofilms ; *Microfluidics ; }, abstract = {The formation of biofilms is a key factor that researchers must consider when they work with bacterial cultures. We describe a new microfluidic bioanalytical sensory system for indicating biofilm formation. The method is demonstrated with Pseudomonas bacteria as an example and is based on the real-time recording of cell-polarizability changes caused by an alternating electric field. Control experiments using phase-contrast microscopy and traditional microbiological plating were done that proved biofilms had formed. The physical picture was described of the sensor-signal changes during cell transition from planktonic to biofilm growth. This transition was indicated by the appearance of a peak-shaped signal at 500 kHz and by an increase in the recorded relaxation time. Phenomena of increase in the signal relaxation time from 2.4 s for planktonic to 25.4 s for biofilm cells. The proposed microfluidic sensor system for indicating biofilm formation holds much promise, because it ensures an analysis time of about 20-30 min. An added bonus is that for this system there is no need to grow bacterial biofilms in a sensor and the flow cell is reusable.}, } @article {pmid35612797, year = {2022}, author = {Prado, MM and Figueiredo, N and Pimenta, AL and Miranda, TS and Feres, M and Figueiredo, LC and de Almeida, J and Bueno-Silva, B}, title = {Recent Updates on Microbial Biofilms in Periodontitis: An Analysis of In Vitro Biofilm Models.}, journal = {Advances in experimental medicine and biology}, volume = {1373}, number = {}, pages = {159-174}, pmid = {35612797}, issn = {0065-2598}, mesh = {Biofilms ; Humans ; *Periodontitis ; Plankton ; Porphyromonas gingivalis/genetics ; *Treponema denticola/genetics ; }, abstract = {The development of oral biofilm models has been extremely important to study the specific role of most microbial species at the early stages of periodontitis. The current knowledge on monospecies or multispecies biofilms originates mainly from the observation of in vitro dynamic or static biofilm model systems, which were engineered to mimic clinical oral conditions. In the last few decades, mounting evidence has confirmed that biofilms are the major form of bacterial lifestyle, and more importantly, that microorganisms dwelling in sessile mixed-species aggregates display completely different phenotypes and physiological characteristics than when living in planktonic pure cultures. Interspecies interactions within these communities, mediated by chemical communication systems, have been shown to affect biofilm physiology and increase antimicrobial resistance by up to 1000 fold. These aspects reinforce the importance of developing multispecies biofilm models to better understand and control biofilms. Literature reports demonstrate that while monospecies models are still most commonly used in caries research, authors have used different multispecies models to study periodontal diseases. Periodontitis is a polymicrobial biofilm-dependent disease mainly associated with Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Interestingly, these species hardly adhere to substrates commonly used for biofilm formation, which makes multispecies models essential for an accurate analysis of periodontitis-related biofilms. The multispecies models currently available are generally composed of 6-10 species, but a more recent 34-species model was developed to better examine the dynamics within oral biofilms. The complexity of such polymicrobial biofilm models mimics more consistently the oral microbiome and different aspects of the oral environment. Collectively, the evidence on multispecies biofilm models described herein may support future studies on the use of antimicrobials for biofilm control as well as provide research opportunities to expand the current knowledge on interspecies interactions. The present manuscript reviews the most recent updates on in vitro biofilm model systems for periodontitis.}, } @article {pmid35612628, year = {2022}, author = {Vega, M and Ontiveros-Valencia, A and Vargas, IT and Nerenberg, R}, title = {Chlorate addition enhances perchlorate reduction in denitrifying membrane-biofilm reactors.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {11}, pages = {4341-4350}, pmid = {35612628}, issn = {1432-0614}, support = {21161573//Agencia Nacional de Investigación y Desarrollo de Chile/ ; 1201134//Fondo Nacional de Desarrollo Científico y Tecnológico/ ; 15110020//Centro de Desarrollo Urbano Sustentable ANID/FONDAP/ ; }, mesh = {Bacteria ; Biofilms ; *Chlorates ; Hydrogen ; Oxidation-Reduction ; *Perchlorates ; Sulfates ; }, abstract = {Perchlorate is a widespread drinking water contaminant with regulatory standards ranging from 2 to 18 μg/L. The hydrogen-based membrane-biofilm reactor (MBfR) can effectively reduce perchlorate, but it is challenging to achieve low-µg/L levels. We explored chlorate addition to increase the abundance of perchlorate-reducing bacteria (PRB) and improve removals. MBfR reactors were operated with and without chlorate addition. Results show that chlorate doubled the abundance of putative PRB (e.g., Rhodocyclales) and improved perchlorate reduction to 23 ± 17 µg/L, compared to 53 ± 37 µg/L in the control. Sulfate reduction was substantially inhibited during chlorate addition, but quickly recovered once suspended. Our results suggest that chlorate addition can enhance perchlorate reduction by providing a selective pressure for PRB. It also decreases net sulfate reduction. KEY POINTS: • Chlorate increased the abundance of perchlorate-reducing bacteria • Chlorate addition improved perchlorate removal • Chlorate appeared to suppress sulfate reduction.}, } @article {pmid35611764, year = {2022}, author = {Wu, X and Wang, B and Ma, Q and Zhang, Y and Xu, J and Zhang, Z and Chen, G}, title = {Mechanism of erythropoietin-induced M2 microglia polarization via Akt / Mtor / P70S6k signaling pathway in the treatment of brain injury in premature mice and its effect on biofilm.}, journal = {Bioengineered}, volume = {13}, number = {5}, pages = {13021-13032}, pmid = {35611764}, issn = {2165-5987}, mesh = {Animals ; Biofilms ; *Brain Injuries ; *Erythropoietin/pharmacology ; Mice ; Microglia/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Proto-Oncogene Proteins c-bcl-2/metabolism ; Ribosomal Protein S6 Kinases, 70-kDa/metabolism ; Signal Transduction ; Superoxide Dismutase/metabolism ; TOR Serine-Threonine Kinases/metabolism ; bcl-2-Associated X Protein/metabolism ; }, abstract = {We investigated the mechanism of erythropoietin (EPO) in brain injury in premature mice based on Akt/mTOR/p70S6K signaling pathway. The brain injury model group of premature mice was obtained by intraperitoneal injection of lipopolysaccharide during pregnancy. Normal mice were taken as the control group. The model mice were divided into low-dose EPO (1,000 IU/kg, L-EPO), medium-dose EPO (2,500 IU/kg, M-EPO), and high-dose EPO groups (5,000 IU/kg, H-EPO) by intraperitoneal injection. The levels of malondialdehyde (MDA) and total superoxide dismutase (T-SOD) were detected. TUNEL staining and Western blotting were used to detect the differences in neuronal apoptosis index (AI), microglial polarization marker protein, and Akt/mTOR/p70S6K-related protein expression levels in each group. Compared with the control group, the protein levels of AI, MDA, Bax, and iNOS in the model, L-EPO, and M-EPO groups were significantly increased, while the T-SOD level and Bcl-2, ARG1, p-Akt, p-mTOR, and p-70S6K protein levels were significantly decreased (P < 0.05). Compared with the model group, AI, MAD levels and Bax, iNOS protein expression levels in L-EPO, M-EPO, and H-EPO groups were significantly decreased, while T-SOD level and Bcl-2, ARG1, p-Akt, p-mTOR, and p-70S6K protein levels were significantly increased. The changes were dose-dependent. In summary, EPO can activate microglia transformation from M1 to M2 through Akt/mTOR/p70S6K signaling pathway.}, } @article {pmid35610631, year = {2022}, author = {Xia, Y and Jayathilake, PG and Li, B and Zuliani, P and Deehan, D and Longyear, J and Stoodley, P and Chen, J}, title = {Coupled CFD-DEM modeling to predict how EPS affects bacterial biofilm deformation, recovery and detachment under flow conditions.}, journal = {Biotechnology and bioengineering}, volume = {119}, number = {9}, pages = {2551-2563}, pmid = {35610631}, issn = {1097-0290}, mesh = {Bacteria ; *Biofilms ; Computer Simulation ; *Extracellular Polymeric Substance Matrix ; Hydrodynamics ; }, abstract = {The deformation and detachment of bacterial biofilm are related to the structural and mechanical properties of the biofilm itself. Extracellular polymeric substances (EPS) play an important role on keeping the mechanical stability of biofilms. The understanding of biofilm mechanics and detachment can help to reveal biofilm survival mechanisms under fluid shear and provide insight about what flows might be needed to remove biofilm in a cleaning cycle or for a ship to remove biofilms. However, how the EPS may affect biofilm mechanics and its deformation in flow conditions remains elusive. To address this, a coupled computational fluid dynamic- discrete element method (CFD-DEM) model was developed. The mechanisms of biofilm detachment, such as erosion and sloughing have been revealed by imposing hydrodynamic fluid flow at different velocities and loading rates. The model, which also allows adjustment of the proportion of different functional groups of microorganisms in the biofilm, enables the study of the contribution of EPS toward biofilm resistance to fluid shear stress. Furthermore, the stress-strain curves during biofilm deformation have been captured by loading and unloading fluid shear stress to study the viscoelastic properties of the biofilm. Our predicted emergent viscoelastic properties of biofilms were consistent with relevant experimental measurements.}, } @article {pmid35609749, year = {2022}, author = {Leggieri, PA and Valentine, MT and O'Malley, MA}, title = {Biofilm disruption enhances growth rate and carbohydrate-active enzyme production in anaerobic fungi.}, journal = {Bioresource technology}, volume = {358}, number = {}, pages = {127361}, doi = {10.1016/j.biortech.2022.127361}, pmid = {35609749}, issn = {1873-2976}, mesh = {Anaerobiosis ; Animals ; Biofilms ; Fungi/metabolism ; *Rumen/microbiology ; *Xylans/metabolism ; }, abstract = {Anaerobic gut fungi (AGF) are lignocellulose degraders that naturally form biofilms in the rumen of large herbivores and in standard culture techniques. While biofilm formation enhances biomass degradation and carbohydrate-active enzyme (CAZyme) production in some bacteria and aerobic fungi, gene expression and metabolism in AGF biofilms have not been compared to non-biofilm cultures. Here, using the tunable morphology of the non-rhizoidal AGF, Caecomyces churrovis, the impacts of biofilm formation on AGF gene expression, metabolic flux, growth rate, and xylan degradation rate are quantified to inform future industrial scale-up efforts. Contrary to previous findings, C. churrovis upregulated catabolic CAZymes in stirred culture relative to biofilm culture. Using a de novo transcriptome, 197 new transcripts with predicted CAZyme function were identified. Stirred cultures grew and degraded xylan significantly faster than biofilm-forming cultures with negligible differences in primary metabolic flux, offering a way to accelerate AGF biomass valorization without altering the fermentation product profile. The rhizoidal AGF, Neocallimastix lanati, also grew faster with stirring on a solid plant substrate, suggesting that the advantages of stirred C. churrovis cultures may apply broadly to other AGF.}, } @article {pmid35607251, year = {2022}, author = {Han, X and Lou, Q and Feng, F and Xu, G and Hong, S and Yao, L and Qin, S and Wu, D and Ouyang, X and Zhang, Z and Wang, X}, title = {Spatiotemporal Release of Reactive Oxygen Species and NO for Overcoming Biofilm Heterogeneity.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {61}, number = {33}, pages = {e202202559}, doi = {10.1002/anie.202202559}, pmid = {35607251}, issn = {1521-3773}, mesh = {*Anti-Infective Agents ; Bacteria ; *Biofilms ; Extracellular Polymeric Substance Matrix ; Reactive Oxygen Species ; }, abstract = {The heterogeneity in biofilms is a major challenge in biofilm therapies due to different susceptibility of bacteria and extracellular polymeric substances (EPS) to antibacterial agents. Here, we describe a therapeutic strategy that overcame biofilm heterogeneity, where antibacterial agent (NO) and EPS dispersant (reactive oxygen species (ROS)-inducing Fe[3+]) were separately loaded in the yolk and shell compartment of a yolk-shell nanoplatform. Compared with traditional combinational chemotherapies which suffer from inconsistent pharmacokinetics profiles, this strategy drew on the pharmacokinetic complementarity of ROS and NO, where ROS with a short diffusion distance and a high redox potential corrupted the EPS, facilitating NO, which has a long diffusion distance and a broad antimicrobial spectrum, to penetrate the biofilm and eliminate the resident bacteria. Additionally, the construction of a three-dimensional spherical biofilm model is novel and clinically relevant.}, } @article {pmid35606635, year = {2022}, author = {Swain, G and Maurya, KL and Kumar, M and Sonwani, RK and Singh, RS and Jaiswal, RP and Nath Rai, B}, title = {The Biodegradation of 4-Chlorophenol in a Moving Bed Biofilm Reactor Using Response Surface Methodology: Effect of Biogenic Substrate and Kinetic Evaluation.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35606635}, issn = {1559-0291}, abstract = {4-Chlorophenol (4-CP) is a persistent organic pollutant commonly found in petrochemical effluents. It causes toxic, carcinogenic and mutagenic effects on human beings and aquatic lives. Therefore, an environmentally benign and cost-effective approach is needed against such pollutants. In this direction, the chlorophenol degrading bacterial consortium consisting of Bacillus flexus GS1 IIT (BHU) and Bacillus cereus GS2 IIT (BHU) was isolated from a refinery site. A composite biocarrier namely polypropylene-polyurethane foam (PP-PUF) was developed for bacterial cells immobilization purpose. A lab-scale moving bed biofilm reactor (MBBR) packed with Bacillus sp. immobilized PP-PUF biocarrier was employed to analyse the effect of peptone on biodegradation of 4-CP. The statistical tool, i.e. response surface methodology (RSM), was used to optimize the process variables (4-CP concentration, peptone concentration and hydraulic retention time). The higher values of peptone concentration and hydraulic retention time were found to be favourable for maximum removal of 4-CP. At the optimized process conditions, the maximum removals of 4-CP and chemical oxygen demand (COD) were obtained to be 91.07 and 75.29%, respectively. In addition, three kinetic models, i.e. second-order, Monod and modified Stover-Kincannon models, were employed to investigate the behaviour of MBBR during 4-CP biodegradation. The high regression coefficients obtained by the second-order and modified Stover-Kincannon models showed better accuracy for estimating substrate degradation kinetics. The phytotoxicity study supported that the Vigna radiata seeds germinated in treated wastewater showed higher growth (i.e. radicle and plumule) than the untreated wastewater.}, } @article {pmid35606284, year = {2022}, author = {Alabdullatif, M and Alzahrani, A}, title = {Expression of biofilm-associated genes in Staphylococcus aureus during storage of platelet concentrates.}, journal = {Transfusion and apheresis science : official journal of the World Apheresis Association : official journal of the European Society for Haemapheresis}, volume = {61}, number = {6}, pages = {103456}, doi = {10.1016/j.transci.2022.103456}, pmid = {35606284}, issn = {1473-0502}, mesh = {Humans ; Biofilms ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics ; *Transfusion Medicine ; Blood Platelets ; }, abstract = {BACKGROUND AND OBJECTIVES: In transfusion medicine, the safety of platelet concentrates (PCs) is a major concern on account of contamination, mostly with Staphylococcus species. One of the most common contaminants is Staphylococcus aureus, which forms bacterial biofilms in PCs, posing a safety risk for transfusion patients. In this study, we investigate the contributions to biofilm formation of eno, ebps, and fib genes encoding surface proteins and of genes from the ica operon (icaA and icaD) encoding polysaccharide intercellular adhesin (PIA), along with their expression in bacteria grown in glucose-supplemented trypticase soy broth (TSBg) and PCs.

MATERIALS AND METHODS: Two strains of S. aureus (2039 and 2110) captured during routine PC screening were tested for biofilm formation in TSBg and under PC storage conditions, with mRNA collected at five time points and analyzed to determine expression of eno, ebps, fib, icaA, and icaD and their contributions to biofilm formation in both media.

RESULTS: In TSBg, S. aureus strain 2039 formed weak biofilms while 2110 formed strong. biofilms; however, in PCs, both strains formed strong biofilms. During biofilm formation, expression levels of icaA and icaD in both strains were generally significantly higher in TSBg than PCs. In contrast, expression of eno, ebps, and fib genes tended to be significantly higher under PC storage conditions.

CONCLUSION: This study demonstrated that expression of genes involved in biofilm formation can be affected by growth media. Further investigation is needed to understand biofilm formation in the PC milieu and enhance transfusion safety.}, } @article {pmid35605925, year = {2022}, author = {Joseph, B and Gopalakrishnan, S and Alamoudi, RA and Alamoudi, RA and Pachathundikandi, SK and Alotaibi, RN and Anil, S}, title = {Detection of invisible dental biofilm using light-induced autofluorescence in adult patients-A systematic review.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {39}, number = {}, pages = {102916}, doi = {10.1016/j.pdpdt.2022.102916}, pmid = {35605925}, issn = {1873-1597}, mesh = {Adult ; Biofilms ; *Dental Plaque ; *Gingivitis/prevention & control ; Humans ; Oral Hygiene ; *Photochemotherapy/methods ; }, abstract = {BACKGROUND: Autofluorescence (AF) spectroscopy is a potent yet non-invasive technique with diagnostic and therapeutic applications. It identifies and characterizes changes occurring in the human body based on the changes in the fluorescence signatures.

AIM: The primary purpose of this systematic review is to address the question "Is it feasible to detect dental plaque using light-induced auto-fluorescence in adult patients with invisible grade 1 plaque?"

MATERIALS AND METHODS: The literature search was conducted independently MEDLINE, Embase, Cochrane Library, Web of Science, Google Scholar, and Scopus databases for relevant studies from January 2000 and June 2021, using the following terms in various combinations: detection, dental biofilm, plaque, light, auto-fluorescence, caries, gingivitis, sensitivity and specificity. Studies describing various fluorescence techniques for the detection of plaque, including sensitivity and specificity, were included.

RESULTS: The majority of the studies indicated that AF spectroscopy allows fluorescence-based detection of various diseases, including early-stage dental plaque. While results of conventional plaque detection techniques are inconsistent, the data from the AF technique is reliable and reproducible, which can be used for patient documentation. However, a wide range of non-uniformity existed in these studies. AF spectroscopy, as a non-invasive technique, represents a viable and patient-friendly clinical tool for the early detection of dental biofilm plaque, and its meticulous removal has been directly responsible for the prevention of this disease.

CONCLUSION: Despite the heterogeneity and limitations of studies included in this review, the future for light-induced autofluorescence spectroscopy technologies in diagnostic dentistry certainly presents an accurate and potentially applicable option.}, } @article {pmid35605773, year = {2022}, author = {Liu, W and Zhou, H and Zhao, W and Wang, C and Wang, Q and Wang, J and Wu, P and Shen, Y and Ji, X and Yang, D}, title = {Rapid initiation of a single-stage partial nitritation-anammox process treating low-strength ammonia wastewater: Novel insights into biofilm development on porous polyurethane hydrogel carrier.}, journal = {Bioresource technology}, volume = {357}, number = {}, pages = {127344}, doi = {10.1016/j.biortech.2022.127344}, pmid = {35605773}, issn = {1873-2976}, mesh = {Ammonia ; *Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Bacteria ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Hydrogels ; In Situ Hybridization, Fluorescence ; Nitrogen ; Oxidation-Reduction ; Polyurethanes ; Porosity ; *Wastewater ; }, abstract = {Media-supported biofilm is a powerful strategy for growth and enrichment of slow-growing microorganisms. In this study, a single-stage nitritation-anammox process treating low-strength wastewater was successfully started to investigate the biofilm development on porous polyurethane hydrogel carrier. Suspended biomass migration into the carrier and being entrapment by its internal interconnected micropores dominated the fast initial colonization stage. Both surface-attached growth and embedded growth of microbes occurred during the following accumulation stage. Fluorescence in situ hybridization analysis of mature biofilm indicated that ammonium-oxidizing bacteria located at the outer layers featured a surface-attached growth, while anammox microcolonies housed in the inner layers proliferated as an embedded-like growth. In this way, the growth rate of anammox bacteria (predominated by Candidatus Kuenenia) could be 0.079 d[-1]. The anammox potential of the biofilm reactor reached 1.65 ± 0.3 kg/m[3]/d within two months. This study provides novel insights into nitritation-anammox biofilm formation on the porous polyurethane hydrogel carrier.}, } @article {pmid35605730, year = {2022}, author = {Bourguignon, N and Alessandrello, M and Booth, R and Lobo, CB and Juárez Tomás, MS and Cumbal, L and Perez, M and Bhansali, S and Ferrero, M and Lerner, B}, title = {Bioremediation on a chip: A portable microfluidic device for efficient screening of bacterial biofilm with polycyclic aromatic hydrocarbon removal capacity.}, journal = {Chemosphere}, volume = {303}, number = {Pt 2}, pages = {135001}, doi = {10.1016/j.chemosphere.2022.135001}, pmid = {35605730}, issn = {1879-1298}, mesh = {Acenaphthenes/metabolism ; Bacteria/metabolism ; Biodegradation, Environmental ; Biofilms ; *Environmental Pollutants/metabolism ; Lab-On-A-Chip Devices ; Microfluidics ; *Polycyclic Aromatic Hydrocarbons/analysis ; Pyrenes/metabolism ; }, abstract = {Polycyclic aromatic hydrocarbons (PAHs) are pollutants of critical environmental and public health concern and their elimination from contaminated sites is significant for the environment. Biodegradation studies have demonstrated the ability of bacteria in biofilm conformation to enhance the biodegradation of pollutants. In this study, we used our newly developed microfluidic platform to explore biofilm development, properties, and applications of fluid flow, as a new technique for screening PAHs-degrading biofilms. The optimization and evaluation of the flow condition in the microchannels were performed through computational fluid dynamics (CFD). The formation of biofilms by PAHs-degrading bacteria Pseudomonas sp. P26 and Gordonia sp. H19, as pure cultures and co-culture, was obtained in the developed microchips. The removal efficiencies of acenaphthene, fluoranthene and pyrene were determined by HPLC. All the biofilms formed in the microchips removed all tested PAHs, with the higher removal percentages observed with the Pseudomonas sp. P26 biofilm (57.4% of acenaphthene, 40.9% of fluoranthene, and 28.9% of pyrene). Pseudomonas sp. P26 biofilm removed these compounds more efficiently than planktonic cultures. This work proved that the conformation of biofilms enhances the removal rate. It also provided a new tool to rapid and low-cost screen for effective pollutant-degrading biofilms.}, } @article {pmid35605455, year = {2022}, author = {Pang, X and Zhang, H and Seck, HL and Zhou, W}, title = {Inactivation effect of low-energy X-ray irradiation against planktonic and biofilm Pseudomonas fluorescens and its antibacterial mechanism.}, journal = {International journal of food microbiology}, volume = {374}, number = {}, pages = {109716}, doi = {10.1016/j.ijfoodmicro.2022.109716}, pmid = {35605455}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/radiation effects ; Plankton ; *Pseudomonas fluorescens ; Stainless Steel/pharmacology ; X-Rays ; }, abstract = {Pseudomonas fluorescens is a well-known biofilm former on food contact surfaces and can cause severe cross-contamination in food processing premises. This study aimed to determine the inactivation effect of low-energy X-ray on P. fluorescens planktonic cells in phosphate-buffered saline solution (PBS) and P. fluorescens biofilm cells on food-contact-surface (stainless steel). The results demonstrated that low-energy X-ray irradiation at 125 Gy inactivated 4.60 log CFU/mL and 4.21 log CFU/cm[2] for P. fluorescens planktonic and biofilm cells, respectively. Based on Weibull model, low-energy X-ray achieved tR1 values of 14.8 Gy and 11.6 Gy for P. fluorescens planktonic and biofilm cells, respectively. Apart from cell inactivation, the irradiation also led to the destruction of extracellular polymeric substances (EPS) structure. Low-energy X-ray irradiation markedly damaged bacterial glucose uptake system and resulted in part loss of bacterial membrane potential and integrity. These results suggested the potential of the low-energy X-ray for inactivating P. fluorescens biofilm cells and removing EPS in food industry.}, } @article {pmid35605361, year = {2022}, author = {Wang, Y and Pan, L and Li, L and Cao, R and Zheng, Q and Xu, Z and Wu, CJ and Zhu, H}, title = {Glycosylation increases the anti-QS as well as anti-biofilm and anti-adhesion ability of the cyclo (L-Trp-L-Ser) against Pseudomonas aeruginosa.}, journal = {European journal of medicinal chemistry}, volume = {238}, number = {}, pages = {114457}, doi = {10.1016/j.ejmech.2022.114457}, pmid = {35605361}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacterial Adhesion ; Biofilms ; Carbohydrates/therapeutic use ; Dipeptides/pharmacology ; Glycosylation ; Humans ; *Pseudomonas Infections/drug therapy ; *Pseudomonas aeruginosa/metabolism ; Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Pseudomonas aeruginosa infections pose a huge threat to cystic fibrosis patients, as well as those suffering from immunodeficiency. Antimicrobial resistance, especially multi-drug resistance, due to its ability to aggregate the compact biofilm, makes it more inefficient to treat this pathogen with traditional antibiotics. Biofilm and quorum sensing (QS) have become the alternative targets for treating P. aeruginosa infections. Previously, a cyclic dipeptide cyclo(L-Trp-L-Ser) has been identified as a QS inhibitor of P. aeruginosa. On the other hand, some monosaccharides have been proved lectin-targeting behavior and to mediate biofilm formation and adhesion of P. aeruginosa. We constructed novel cyclic dipeptide-carbohydrate conjugates as a low molecular weight dual-functional QS inhibitor, which can not only enhance its anti-QS activity but also enable good anti-biofilm and anti-adhesion ability. The IC50 of galactosylated c(WS) on biofilm formation and glass adhesion was 1/6 and 1/4 of that of the unmodified cyclic dipeptide, respectively. And the ability to eliminate the preformed biofilm was increased 10-fold. Furthermore, the carbohydrate conjugates can increase the germicidal efficiency of clinical antibiotic azithromycin when used synergistically. Our results provide a novel scaffold for developing anti-virulence adjuvants when taken with clinical antibiotics.}, } @article {pmid35604533, year = {2022}, author = {Wang, C and Li, C and Li, X and Cai, L and Han, Z and Du, R}, title = {RETRACTED ARTICLE: Burn Wounds: Proliferating Site for Biofilm Infection.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12010-022-03964-y}, pmid = {35604533}, issn = {1559-0291}, } @article {pmid35603698, year = {2022}, author = {Khosravi, Y and Palmer, S and Daep, CA and Sambanthamoorthy, K and Kumar, P and Dusane, DH and Stoodley, P}, title = {A commercial SnF2 toothpaste formulation reduces simulated human plaque biofilm in a dynamic typodont model.}, journal = {Journal of applied microbiology}, volume = {133}, number = {3}, pages = {1341-1352}, pmid = {35603698}, issn = {1365-2672}, support = {None//Colgate-Palmolive Company/ ; }, mesh = {Biofilms ; Humans ; Saliva ; *Tin Fluorides/therapeutic use ; *Toothpastes/pharmacology/therapeutic use ; }, abstract = {AIMS: We present a dynamic typodont biofilm model (DTBM) incorporating (1) human dentition anatomy, (2) fluid flow over intermittently fluid bathed tooth surfaces and (3) an oxic headspace to allow aerobic and anaerobic niches to develop naturally, as a screening tool to assess the effect of stannous fluoride (SnF2) toothpaste against a simulated human plaque biofilm (SPB).

METHODS AND RESULTS: First, hydroxyapatite (HA) coupons were inoculated with human saliva/plaque and cultured at 37°C under air. Selected species representative of common commensal and anaerobic pathogens were quantified for relative abundance changes over 4 days by PCR densitometry to confirm the culture conditions allowed the proliferation of these species. A continuous culture DTBM reactor on a rocker table was inoculated with saliva/plaque and incubated at 37°C for 24 h. Tooth shear stress was estimated by particle tracking. A SnF2 toothpaste solution, or a sham rise was administered twice daily for 3 days to mimic routine oral hygiene. SPB biomass was assessed by total bacterial DNA and methylene blue (MB) staining. Early colonizer aerobes and late colonizer anaerobes species were detected in the HA and DTBM, and the trends in changing abundance were consistent with those seen clinically.

CONCLUSIONS: Treatment with the SnF2 solution showed significant reductions of 53.05% and 54.4% in the SPB by MB staining and DNA, respectively.

The model has potential for assessing dentition anatomy and fluid flow on the efficacy of antimicrobial efficacy against localized SPB and may be amenable to the plaque index clinical evaluation.}, } @article {pmid35602061, year = {2022}, author = {Cheng, C and Yan, X and Liu, B and Jiang, T and Zhou, Z and Guo, F and Zhang, Q and Li, C and Fang, T}, title = {SdiA Enhanced the Drug Resistance of Cronobacter sakazakii and Suppressed Its Motility, Adhesion and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {901912}, pmid = {35602061}, issn = {1664-302X}, abstract = {Cronobacter sakazakii is a common foodborne pathogen, and the mortality rate of its infection is as high as 40-80%. SdiA acts as a quorum sensing regulator in many foodborne pathogens, but its role in C. sakazakii remains unclear. Here, we further determined the effect of the sdiA gene in C. sakazakii pathogenicity. The SdiA gene in C. sakazakii was knocked out by gene editing technology, and the biological characteristics of the ΔsdiA mutant of C. sakazakii were studied, followed by transcriptome analysis to elucidate its effects. The results suggested that SdiA gene enhanced the drug resistance of C. sakazakii but diminished its motility, adhesion and biofilm formation ability and had no effect on its growth. Transcriptome analysis showed that the ΔsdiA upregulated the expression levels of D-galactose operon genes (including dgoR, dgoK, dgoA, dgoD and dgoT) and flagella-related genes (FliA and FliC) in C. sakazakii and downregulated the expression levels of related genes in the type VI secretion system (VasK gene was downregulated by 1.53-fold) and ABC transport system (downregulated by 1.5-fold), indicating that SdiA gene was related to the physiological metabolism of C. sakazakii. The results were useful for clarifying the pathogenic mechanism of C. sakazakii and provide a theoretical basis for controlling bacterial infection.}, } @article {pmid35601098, year = {2022}, author = {Rosca, AS and Castro, J and Sousa, LGV and França, A and Cavaleiro, C and Salgueiro, L and Cerca, N}, title = {Six Bacterial Vaginosis-Associated Species Can Form an In Vitro and Ex Vivo Polymicrobial Biofilm That Is Susceptible to Thymbra capitata Essential Oil.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {824860}, pmid = {35601098}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Female ; Gardnerella ; Humans ; *Oils, Volatile/pharmacology ; Pregnancy ; Vagina/microbiology ; *Vaginosis, Bacterial/microbiology ; }, abstract = {Bacterial vaginosis (BV) is associated with serious gynaecologic and obstetric complications. The hallmark of BV is the presence of a polymicrobial biofilm on the vaginal epithelium, but BV aetiology is still a matter of debate. We have previously developed an in vitro biofilm model that included three BV-associated species, but, up to now, no studies are available whereby more bacterial species are grown together to better mimic the in vivo situation. Herein, we characterized the first polymicrobial BV biofilm consisting of six cultivable BV-associated species by using both in vitro and ex vivo vaginal tissue models. Both models revealed that the six species were able to incorporate the polymicrobial biofilm, at different bacterial concentrations. As it has been thought that this polymicrobial biofilm may increase the survival of BV-associated species when exposed to antibiotics, we also assessed if the Thymbra capitata essential oil (EO), which has recently been shown to be highly bactericidal against several Gardnerella species, could maintain its anti-biofilm activity against this polymicrobial biofilm. Under our experimental conditions, T. capitata EO exhibited a high antibacterial effect against polymicrobial biofilms, in both tested models, with a significant reduction in the biofilm biomass and the number of culturable cells. Overall, this study shows that six BV-associated species can grow together and form a biofilm both in vitro and when using an ex vivo model. Moreover, the data obtained herein should be considered in further applications of T. capitata EO as an antimicrobial agent fighting BV.}, } @article {pmid35600163, year = {2022}, author = {Pan, T and Liu, FS and Lin, H and Zhou, Y}, title = {Anti-biofilm studies of synthetic imidazolium salts on dental biofilm in vitro.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {2075309}, pmid = {35600163}, issn = {2000-2297}, abstract = {OBJECTIVE: Biofilm formation under cariogenic conditions contributes to dental caries development, in which Streptococcus mutans (S. mutans) is regarded as the major cariogenic bacteria. Here, we synthesized a series of imidazolium salts. Their properties of antimicrobial and anti-biofilm were investigated.

METHODS: The microdilution method crystal violet staining, and cell counting Kit-8 assay were used to screen imidazolium salts. Then, the bacterial composition in multi-species biofilm composed of S. mutans, Actinomyces naeslundii, and Streptococcus gordonii was quantified by quantitative PCR. The exopolysaccharide and morphology of the structure of multi-species biofilm were further observed by confocal laser scanning microscopy and scanning electron microscope, respectively.

RESULTS: Imidazolium salts exhibited highly antimicrobial activity against oral pathogens, especially for S. mutans . Compounds with ortho-diisopropyl and para-methoxyl on N-moieties as well as bearing ancenaphthyl skeleton (C5) showed the lowest cytotoxicity and most efficient anti-biofilm activity. C5 inhibited approximately 50% of multi-species biofilm at 0.98 μg/mL. Notably, C5 resulted in 98.97% live S. mutans and 77.65% A. naeslundii decreased. Furthermore, the exopolysaccharide was reduced by 88%, along with a sparse and scattered microstructure.

CONCLUSION: The imidazolium salts present low cytotoxicity and remarkable antimicrobial activity against S. mutans in multi-species biofilm, suggesting that they may have a great potential in anti-biofilm clinical applications.}, } @article {pmid35598875, year = {2022}, author = {Abbott, C and Grout, E and Morris, T and Brown, HL}, title = {Cutibacterium acnes biofilm forming clinical isolates modify the formation and structure of Staphylococcus aureus biofilms, increasing their susceptibility to antibiotics.}, journal = {Anaerobe}, volume = {76}, number = {}, pages = {102580}, doi = {10.1016/j.anaerobe.2022.102580}, pmid = {35598875}, issn = {1095-8274}, mesh = {*Acne Vulgaris ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Propionibacterium acnes ; Staphylococcus ; Staphylococcus aureus ; }, abstract = {Cutibacterium acnes (formally Propionibacterium acnes) is frequently identified within surgical device related infections. It is often co-isolated from infection sites with other opportunistic pathogens. Recent studies have demonstrated that C. acnes is able to form biofilms and when co-cultured with Staphylococcus spp. both inhibitory and stimulatory effects have been reported across several studies. Here, we investigated the biofilm-forming ability of 100 clinical C. acnes isolates from various infection sites in human patients, both deep tissue and superficial, followed by an investigation of how the supernatants of C. acnes cultures influenced the attachment and maturation of Staphylococcusaureus NCTC 6571 biofilms. All of the C. acnes isolates were able to form biofilms in vitro, although biofilm biomass varied between isolates. Nineteen isolates were weakly adherent, 33 were moderately adherent and the majority (48) showed strong adherence. The presence of C. acnes sterile supernatants reduced the biomass of S. aureus cultures, with a > 90% reduction observed in the presence of several of the C. acnes isolates. We observed that this decrease was not due to C. acnes affecting S. aureus viability, nor due to the presence of propionic acid. Biofilm maturation was however delayed over a 24-h period as was biofilm surface structure, although initial (up to 8 h) surface attachment was not affected. We hypothesis that this defective biofilm maturation is the cause of the observed biomass decrease. In turn, these altered biofilms showed a greater susceptibility to antibiotic treatments. In contrast the presence of C. acnes supernatant in planktonic (defined as a free moving, non-surface attached population within the liquid column) S. aureus cultures increased antibiotic tolerance, via a currently undefined mechanism. This study suggests that complex interactions between C. acnes and other opportunistic pathogens are likely to exist during colonisation and infection events. Further investigation of these interactions may lead to increased treatment options and a better prognosis for patients.}, } @article {pmid35598240, year = {2022}, author = {Yadav, J and Das, S and Singh, S and Jyoti, A and Srivastava, VK and Sharma, V and Kumar, S and Kumar, S and Kaushik, S}, title = {Deciphering the Role of S-adenosyl Homocysteine Nucleosidase in Quorum Sensing Mediated Biofilm Formation.}, journal = {Current protein & peptide science}, volume = {23}, number = {4}, pages = {211-225}, doi = {10.2174/1389203723666220519152507}, pmid = {35598240}, issn = {1875-5550}, mesh = {Bacteria/metabolism ; Biofilms ; Homocysteine ; Humans ; Methionine ; *N-Glycosyl Hydrolases/chemistry/metabolism ; *Quorum Sensing ; }, abstract = {S-adenosylhomocysteine nucleosidase (MTAN) is a protein that plays a crucial role in several pathways of bacteria that are essential for its survival and pathogenesis. In addition to the role of MTAN in methyl-transfer reactions, methionine biosynthesis, and polyamine synthesis, MTAN is also involved in bacterial quorum sensing (QS). In QS, chemical signaling autoinducer (AI) secreted by bacteria assists cell to cell communication and is regulated in a cell density-dependent manner. They play a significant role in the formation of bacterial biofilm. MTAN plays a major role in the synthesis of these autoinducers. Signaling molecules secreted by bacteria, i.e., AI-1 are recognized as acylated homoserine lactones (AHL) that function as signaling molecules within bacteria. QS enables bacteria to establish physical interactions leading to biofilm formation. The formation of biofilm is a primary reason for the development of multidrug-resistant properties in pathogenic bacteria like Enterococcus faecalis (E. faecalis). In this regard, inhibition of E. faecalis MTAN (EfMTAN) will block the QS and alter the bacterial biofilm formation. In addition to this, it will also block methionine biosynthesis and many other critical metabolic processes. It should also be noted that inhibition of EfMTAN will not have any effect on human beings as this enzyme is not present in humans. This review provides a comprehensive overview of the structural-functional relationship of MTAN. We have also highlighted the current status, enigmas that warrant further studies, and the prospects for identifying potential inhibitors of EfMTAN for the treatment of E. faecalis infections. In addition to this, we have also reported structural studies of EfMTAN using homology modeling and highlighted the putative binding sites of the protein.}, } @article {pmid35598180, year = {2022}, author = {Gregory, ER and Bakhaider, RF and Gomez, GF and Huang, R and Moser, EAS and Gregory, RL}, title = {Evaluating hop extract concentrations found in commercial beer to inhibit Streptococcus mutans biofilm formation.}, journal = {Journal of applied microbiology}, volume = {133}, number = {3}, pages = {1333-1340}, pmid = {35598180}, issn = {1365-2672}, mesh = {Acids/pharmacology ; Anti-Bacterial Agents/pharmacology ; Beer ; Biofilms ; *Dental Caries ; Humans ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; *Streptococcus mutans ; }, abstract = {AIMS: The purpose of this study was to compare the effect of hop extracts with diverse β-acid concentrations on Streptococcus mutans biofilm formation.

METHODS AND RESULTS: Ten different hop extracts, with α-acid concentrations similar to those found in commercial beer products and β-acid concentrations ranging from 2.6 to 8.1%, were added to distilled water to make standardized concentrations. S. mutans isolates were treated with hop extract dilutions varying from 1:2 to 1:256. The minimum inhibitory, minimum bactericidal and minimum biofilm inhibitory concentrations were determined and the optical density was evaluated. Live/dead staining confirmed the bactericidal effects. Biofilm formation of several strains of S. mutans was significantly inhibited by hop extract dilutions of 1:2, 1:4, 1:8, 1:16 and 1:32. Strong negative correlations were observed between α- and β-acid concentrations of the hop extracts and S. mutans total growth and biofilm formation.

CONCLUSIONS: The use of hop extracts prepared similarly to commercial beer decreased S. mutans biofilm formation.

The inclusion of hops in the commercial beer products may provide beneficial health effects. Further studies are warranted to determine an effect in vivo on the development of dental caries.}, } @article {pmid35597812, year = {2022}, author = {Stabnikova, O and Stabnikov, V and Marinin, A and Klavins, M and Vaseashta, A}, title = {The role of microplastics biofilm in accumulation of trace metals in aquatic environments.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {7}, pages = {117}, pmid = {35597812}, issn = {1573-0972}, mesh = {Biofilms ; *Environmental Pollutants ; Humans ; Microplastics ; Plastics ; *Trace Elements ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microplastics are one of the major contaminants of aquatic nature where they can interact with organic and inorganic pollutants, including trace metals, and adsorb them. At the same time, after the microplastics have entered the aquatic environments, they are quickly covered with a biofilm - microorganisms which are able to produce extracellular polymeric substances (EPS) that can facilitate sorption of trace metals from surrounding water. The microbial community of biofilm contains bacteria which synthesizes EPS with antimicrobial activity making them more competitive than other microbial inhabitants. The trace metal trapping by bacterial EPS can inhibit the development of certain microorganisms, therefore, a single microparticle participates in complex interactions of the diverse elements surrounding it. The presented review aims to consider the variety of interactions associated with the adsorption of trace metal ions on the surface of microplastics covered with biofilm, the fate of such microplastics and the ever-increasing risk to the environment caused by the combination of these large-scale pollutants - microplastics and trace metals. Since aquatic pollution problems affect the entire planet, strict regulation of the production, use, and disposal of plastic materials is needed to mitigate the effects of this emerging pollutant and its complexes could have on the environment and human health.}, } @article {pmid35597221, year = {2022}, author = {Wang, N and Feng, Y and Li, Y and Zhang, L and Liu, J and Li, N and He, W}, title = {Effects of ammonia on electrochemical active biofilm in microbial electrolysis cells for synthetic swine wastewater treatment.}, journal = {Water research}, volume = {219}, number = {}, pages = {118570}, doi = {10.1016/j.watres.2022.118570}, pmid = {35597221}, issn = {1879-2448}, mesh = {Acetates/metabolism ; Ammonia ; Animals ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; Electrolysis ; Extracellular Polymeric Substance Matrix/metabolism ; Hydrogen/metabolism ; Methane ; Sucrose ; Swine ; Wastewater ; *Water Purification ; }, abstract = {When facing wastewater with high organic and ammonia, e. g. swine wastewater, microbial electrolysis cell (MEC) is emerging for energy extraction as hydrogen and methane. However, the effects of highly concentrated ammonia on MEC haven't been fully evaluated. In this study, single-chamber MECs were operated with acetate and sucrose as substrates under various ammonia concentrations. The current generally increased with ammonia loading from 80 to 3000 mg L[-1]. Yet, the substrate consumption in MECs was inhibited with ammonia concentrations above 1000 mg L[-1]. As a combined result, the energy recovery efficiency of MECs was stable. The electrochemical activity of anode biofilm reached the peak under 1000 mg L[-1] ammonia and was restricted under higher ammonia loadings. Under neutral pH, the NH4[+] increases the cell membrane permeability, which benefited the electrochemical activity of exoelectrogens to a proper extent. Nevertheless, the toxic ammonia also accelerated the anode biomass loss and stimulated the extracellular polymeric substance (EPS) secretion. Due to the current increase, the abundance of exoelectrogens generally raised with ammonia loading from 80 to 3000 mg L[-1]. However, except for anode biomass loss, the carbon and methane metabolism pathways were inhibited in acetate-fed MEC, while the glycolysis acted as the rate-limiting step for substrate degradation in sucrose-fed conditions. This study systematically examined the influences of high ammonia loading on MEC performances, bio-community and anode electrochemical activities, and evaluated practical feasibility and application inch of MECs for the energy recovery and pollutant removal of high concentration organic and ammonia wastewater.}, } @article {pmid35594757, year = {2022}, author = {Kumar, M and Kumar, R and Chaudhary, DR and Jha, B}, title = {An appraisal of early stage biofilm-forming bacterial community assemblage and diversity in the Arabian Sea, India.}, journal = {Marine pollution bulletin}, volume = {180}, number = {}, pages = {113732}, doi = {10.1016/j.marpolbul.2022.113732}, pmid = {35594757}, issn = {1879-3363}, mesh = {*Bacteria/genetics ; Biofilms ; Plastics ; Proteobacteria/genetics ; RNA, Ribosomal, 16S ; *Seawater/microbiology ; }, abstract = {The community composition and distribution of early-stage (24 h) biofilm-forming bacteria on two different surfaces (glass slide and polystyrene plastic slide) at three different locations (Diu, Alang and Sikka) were studied using a culture-dependent and next-generation sequencing (NGS) approach in the Arabian Sea, Gujarat, India. The most dominant phyla observed using the NGS approach were the Proteobacteria among the sampling sites. Gammaproteobacteria class dominated both the surfaces among the sites and accounted for 46.7% to 89.2% of total abundance. The culture-dependent analysis showed Proteobacteria and Firmicutes as the dominant phyla on the surfaces within the sampling sites. During the initial colonization, hydrocarbon-degrading bacterial strains have also attached to the surfaces. The outcome of this study would be of great importance for targeting the early stage biofilm-forming and hydrocarbon-degrading bacterial isolates may help to degrade plastic in the marine environment.}, } @article {pmid35594665, year = {2022}, author = {Liu, A and Lin, W and Ming, R and Guan, W and Wang, X and Hu, N and Ren, Y}, title = {Stability of 28 typical prescription drugs in sewer systems and interaction with the biofilm bacterial community.}, journal = {Journal of hazardous materials}, volume = {436}, number = {}, pages = {129142}, doi = {10.1016/j.jhazmat.2022.129142}, pmid = {35594665}, issn = {1873-3336}, mesh = {Bacteria ; Biofilms ; Biomarkers ; Humans ; *Prescription Drugs ; Sewage/chemistry ; Wastewater/chemistry ; *Water Pollutants, Chemical/analysis ; }, abstract = {Identifying the attenuation characteristics of drugs in sewage and sewers is one of the important factors to improve the accuracy of wastewater-based epidemiology (WBE) application. In this study, 28 drugs including antidepressants, cardiovascular drugs, antihistamines, anticonvulsants and some of their human metabolites were chosen as the targets to study the hydrolysis, adsorption, and biodegradation at different temperatures in sewage and sewers. The interaction between drugs degradation and community structure of biofilm was also investigated. In the simulated sewers, the removal percentages of 12 parent or drug metabolites are 0-20%, such as demethylvenlafaxine, fluvoxamine, etc., which are highly stable chemicals and suitable to be chosen as biomarkers for WBE back-calculation under appropriate circumstances. Fourteen drugs including venlafaxine and citalopram have removal percentages of 20-60%. While paroxetine and sertraline, with removal percentage of 100%, are the most unstable and cannot be used as biomarkers. Among the 28 drugs, there are 25 drugs that have a higher loss rate in the aerobic sewer than that in the anaerobic sewer in this study. During drug exposure in anaerobic biofilms, species abundance first decreased and then increased. Species abundance and diversity in aerobic biofilm generally showed a decreasing trend. In addition, Proteobacteria and Spirochaetota were the dominant phyla in both sewers.}, } @article {pmid35593953, year = {2022}, author = {Ray, S and Jin, JO and Choi, I and Kim, M}, title = {Cell-Free Supernatant of Bacillus thuringiensis Displays Anti-Biofilm Activity Against Staphylococcus aureus.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35593953}, issn = {1559-0291}, support = {2020 R1A6A1A03044512//Innovative Research Group Project of the National Natural Science Foundation of China/ ; }, abstract = {Staphylococcus aureus is an important bacterial pathogen responsible for biofilm formation in medical devices. Due to the increasing antibiotic resistance of S. aureus, it is necessary to search for new anti-biofilm agents. In this study, the cell-free supernatant of Bacillus thuringiensis inhibited biofilm formation up to 93% and dispersed biofilms up to 83% without affecting the growth of S. aureus. The ethyl acetate extract of B. thuringiensis cell-free supernatant exhibited a dose-dependent anti-biofilm activity against S. aureus with the biofilm inhibition concentration ranging from 8 to 64 µg/mL. Scanning electron microscopy revealed that the cell-free supernatant extract of B. thuringiensis resulted in a significant reduction in S. aureus biofilms. The ethyl acetate extract of cell-free supernatant of B. thuringiensis was found to contain various compounds with structural similarity to known anti-biofilm compounds. In particular, squalene, cinnamic acid derivatives, and eicosapentaene seem to act synergistically against S. aureus biofilms. Hence, B. thuringiensis cell-free supernatant proved to be effective against S. aureus biofilms. The results clearly show the potential of natural molecules produced by B. thuringiensis as alternative therapies with anti-biofilm activity instead of bactericidal properties.}, } @article {pmid35591562, year = {2022}, author = {Sarfraz, S and Mäntynen, PH and Laurila, M and Suojanen, J and Saarnio, J and Rossi, S and Horelli, J and Kaakinen, M and Leikola, J and Reunanen, J}, title = {Effect of Surface Tooling Techniques of Medical Titanium Implants on Bacterial Biofilm Formation In Vitro.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {9}, pages = {}, pmid = {35591562}, issn = {1996-1944}, support = {243032491//Academy of Finland/ ; }, abstract = {The aim of this study was to assess the biofilm formation of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli on titanium implants with CAD-CAM tooling techniques. Twenty specimens of titanium were studied: Titanium grade 2 tooled with a Planmeca CAD-CAM milling device (TiGrade 2), Ti6Al4V grade 5 as it comes from CAD-DMLS device (computer aided design-direct metal laser sintering device) (TiGrade 5), Ti6Al4V grade 23 as it comes from a CAD-CAM milling device (TiGrade 23), and CAD-DMLS TiGrade 5 polished with an abrasive disc (TiGrade 5 polished). Bacterial adhesion on the implants was completed with and without saliva treatment to mimic both extraoral and intraoral surgical methods of implant placement. Five specimens/implant types were used in the bacterial adhesion experiments. Autoclaved implant specimens were placed in petri plates and immersed in saliva solution for 30 min at room temperature and then washed 3× with 1× PBS. Bacterial suspensions of each strain were made and added to the specimens after saliva treatment. Biofilm was allowed to form for 24 h at 37 °C and the adhered bacteria was calculated. Tooling techniques had an insignificant effect on the bacterial adhesion by all the bacterial strains studied. However, there was a significant difference in biofilm formation between the saliva-treated and non-saliva-treated implants. Saliva contamination enhanced S. mutans, S. aureus, and E. faecalis adhesion in all material types studied. S. aureus was found to be the most adherent strain in the saliva-treated group, whereas E. coli was the most adherent strain in the non-saliva-treated group. In conclusion, CAD-CAM tooling techniques have little effect on bacterial adhesion. Saliva coating enhances the biofilm formation; therefore, saliva contamination of the implant must be minimized during implant placement. Further extensive studies are needed to evaluate the effects of surface treatments of the titanium implant on soft tissue response and to prevent the factors causing implant infection and failure.}, } @article {pmid35591238, year = {2022}, author = {Nakagawa, R and Saito, K and Kanematsu, H and Miura, H and Ishihara, M and Barry, DM and Kogo, T and Ogawa, A and Hirai, N and Hagio, T and Ichino, R and Ban, M and Yoshitake, M and Zimmermann, S}, title = {Impedance Characteristics of Monolayer and Bilayer Graphene Films with Biofilm Formation and Growth.}, journal = {Sensors (Basel, Switzerland)}, volume = {22}, number = {9}, pages = {}, pmid = {35591238}, issn = {1424-8220}, mesh = {Bacteria ; Biofilms ; Carbon ; *Cardiovascular Diseases ; Electric Impedance ; *Graphite ; Humans ; Polymers ; }, abstract = {Biofilms are the result of bacterial activity. When the number of bacteria (attached to materials' surfaces) reaches a certain threshold value, then the bacteria simultaneously excrete organic polymers (EPS: extracellular polymeric substances). These sticky polymers encase and protect the bacteria. They are called biofilms and contain about 80% water. Other components of biofilm include polymeric carbon compounds such as polysaccharides and bacteria. It is well-known that biofilms cause various medical and hygiene problems. Therefore, it is important to have a sensor that can detect biofilms to solve such problems. Graphene is a single-atom-thick sheet in which carbon atoms are connected in a hexagonal shape like a honeycomb. Carbon compounds generally bond easily to graphene. Therefore, it is highly possible that graphene could serve as a sensor to monitor biofilm formation and growth. In our previous study, monolayer graphene was prepared on a glass substrate by the chemical vapor deposition (CVD) method. Its biofilm forming ability was compared with that of graphite. As a result, the CVD graphene film had the higher sensitivity for biofilm formation. However, the monolayer graphene has a mechanical disadvantage when used as a biofilm sensor. Therefore, for this new research project, we prepared bilayer graphene with high mechanical strength by using the CVD process on copper substrates. For these specimens, we measured the capacitance component of the specimens' impedance. In addition, we have included a discussion about the possibility of applying them as future sensors for monitoring biofilm formation and growth.}, } @article {pmid35589849, year = {2022}, author = {Giri, AK and Jena, B and Biswal, B and Pradhan, AK and Arakha, M and Acharya, S and Acharya, L}, title = {Green synthesis and characterization of silver nanoparticles using Eugenia roxburghii DC. extract and activity against biofilm-producing bacteria.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {8383}, pmid = {35589849}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/chemistry ; Bacteria ; Biofilms ; *Eugenia ; Green Chemistry Technology ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/pharmacology ; Silver/pharmacology ; X-Ray Diffraction ; }, abstract = {The green synthesis of silver nanoparticles (AgNPs) and their applications have attracted many researchers as the AgNPs are used effectively in targeting specific tissues and pathogenic microorganisms. The purpose of this study is to synthesize and characterize silver nanoparticles from fully expanded leaves of Eugenia roxburghii DC., as well as to test their effectiveness in inhibiting biofilm production. In this study, at 0.1 mM concentration of silver nitrate (AgNO3), stable AgNPs were synthesized and authenticated by monitoring the color change of the solution from yellow to brown, which was confirmed with spectrophotometric detection of optical density. The crystalline nature of these AgNPs was detected through an X-Ray Diffraction (XRD) pattern. AgNPs were characterized through a high-resolution transmission electron microscope (HR-TEM) to study the morphology and size of the nanoparticles (NPs). A new biological approach was undertaken through the Congo Red Agar (CRA) plate assay by using the synthesized AgNPs against biofilm production. The AgNPs effectively inhibit biofilm formation and the biofilm-producing bacterial colonies. This could be a significant achievement in contending with many dynamic pathogens.}, } @article {pmid35586693, year = {2022}, author = {Sun, Y and Sun, F and Feng, W and Wang, Q and Liu, F and Xia, P and Qiu, X}, title = {Luteolin Inhibits the Biofilm Formation and Cytotoxicity of Methicillin-Resistant Staphylococcus aureus via Decreasing Bacterial Toxin Synthesis.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2022}, number = {}, pages = {4476339}, pmid = {35586693}, issn = {1741-427X}, abstract = {Owing to the fact that luteolin has antibacterial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), its specific mechanism in MRSA is worthy of investigation, which is the focus of this study. Initially, the collected S. aureus strains were treated with luteolin. Then, the minimum inhibitory concentration (MIC) of luteolin against the S. aureus strains was measured by the broth microdilution. The growth curves, biofilm formation, and cytotoxicity of treated S. aureus were detected using a microplate reader. The live and dead bacteria were evaluated using confocal laser scanning microscopy, the bacterial morphology was observed using scanning electron microscopy, and the S. aureus colony-forming unit (CFU) numbers were assessed. The levels of alpha hemolysin (α-hemolysin), delta hemolysin (δ-hemolysin), and hlaA were detected via western blot and RT-PCR. The mortality of mouse model with S. aureus systemic infection was analyzed, and the levels of IL-6, IL-8, IL-10, and TNF-α were quantitated using ELISA. Concretely, the MIC of luteolin against MRSA N315 was 64 μg/mL. Luteolin at 16 μg/mL did not affect the growth of MRSA N315, but inhibited the biofilm formation and CFU, and promoted the morphological changes and death of MRSA N315. Luteolin decreased the cytotoxicity and the levels of α-hemolysin, δ-hemolysin, and hlaA in MRSA N315, elevated MRSA-reduced mice survival rate, and differentially modulated the inflammatory cytokine levels in MRSA-infected mice. Collectively, luteolin inhibits biofilm formation and cytotoxicity of MRSA via blocking the bacterial toxin synthesis.}, } @article {pmid35584310, year = {2023}, author = {Costa, RC and Bertolini, M and Costa Oliveira, BE and Nagay, BE and Dini, C and Benso, B and Klein, MI and Barāo, VAR and Souza, JGS}, title = {Polymicrobial biofilms related to dental implant diseases: unravelling the critical role of extracellular biofilm matrix.}, journal = {Critical reviews in microbiology}, volume = {49}, number = {3}, pages = {370-390}, doi = {10.1080/1040841X.2022.2062219}, pmid = {35584310}, issn = {1549-7828}, mesh = {Humans ; *Anti-Infective Agents ; Biofilms ; *Dental Implants ; Extracellular Matrix ; Extracellular Polymeric Substance Matrix ; }, abstract = {Biofilms are complex tri-dimensional structures that encase microbial cells in an extracellular matrix comprising self-produced polymeric substances. The matrix rich in extracellular polymeric substance (EPS) contributes to the unique features of biofilm lifestyle and structure, enhancing microbial accretion, biofilm virulence, and antimicrobial resistance. The role of the EPS matrix of biofilms growing on biotic surfaces, especially dental surfaces, is largely unravelled. To date, there is a lack of a broad overview of existing literature concerning the relationship between the EPS matrix and the dental implant environment and its role in implant-related infections. Here, we discuss recent advances in the critical role of the EPS matrix on biofilm growth and virulence on the dental implant surface and its effect on the etiopathogenesis and progression of implant-related infections. Similar to other biofilms associated with human diseases/conditions, EPS-enriched biofilms on implant surfaces promote microbial accumulation, microbiological shift, cross-kingdom interaction, antimicrobial resistance, biofilm virulence, and, consequently, peri-implant tissue damage. But intriguingly, the protagonism of EPS role on implant-related infections and the development of matrix-target therapeutic strategies has been neglected. Finally, we highlight the need for more in-depth analyses of polymicrobial interactions within EPS matrix and EPS-targeting technologies' rationale for disrupting the complex biofilm microenvironment with more outstanding translation to implant applications in the near future.}, } @article {pmid35579972, year = {2022}, author = {Bi, H and Deng, R and Liu, Y}, title = {Linezolid decreases Staphylococcus aureus biofilm formation by affecting the IcaA and IcaB proteins.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {}, number = {}, pages = {}, doi = {10.1556/030.2022.01689}, pmid = {35579972}, issn = {1588-2640}, abstract = {BACKGROUND: The ica gene of Staphylococcus aureus (S. aureus) plays a vital role in its growth and biofilm formation. Among them, IcaA and IcaB are critical proteins for synthesizing extracellular polysaccharides and biofilms in S. aureus. To investigate whether the formation of S. aureus biofilms can be inhibited through the IcaA and IcaB proteins by the presence of linezolid.

METHODS: The icaA and icaB genes of S. aureus ATCC 25923 were silenced by homologous recombination. The critical roles of icaA and icaB in S. aureus were analysed by observing the growth curve and biofilm formation after linezolid treatment. Then, the effect of linezolid on the morphology of S. aureus was observed by scanning electron microscopy. Finally, the potential binding ability of linezolid to Ica proteins was predicted by molecular docking.

RESULTS: The icaA- and icaB-silenced strains were successfully constructed, and the sensitivity of S. aureus to linezolid was decreased after icaA and icaB silencing. Scanning electron microscopy showed that linezolid caused invagination of the S. aureus surface and reduced the production of biofilms. Molecular docking results showed that linezolid could bind to IcaA and IcaB proteins.

CONCLUSION: IcaA and IcaB are potential targets of linezolid in inhibiting the biofilm formation of S. aureus (ATCC 25923).}, } @article {pmid35579742, year = {2022}, author = {Bhadra, S and Chettri, D and Kumar Verma, A}, title = {Biosurfactants: Secondary Metabolites Involved in the Process of Bioremediation and Biofilm Removal.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35579742}, issn = {1559-0291}, abstract = {The search for environmentally friendly methods to remove persistent substances such as organic pollutants and sessile communities such as biofilms that severely affect the environment and human health resulted in biosurfactant discovery. Owing to their low level of toxicity and high biodegradability, biosurfactants are increasingly preferred to be used for removal of pollutants from nature. These amphipathic molecules can be synthesized inexpensively, employing cheap substrates such as agricultural and industrial wastes. Recent progress has been made in identifying various biosurfactants that can be used to remove organic pollutants and harmful microbial aggregates, as well as novel microbial strains that produce these surface-active molecules to survive in a hydrocarbon-rich environment. This review focuses on the identification and understanding the role of biosurfactants and the microorganisms involved in the removal of biofilms and remediation of xenobiotics and various types of hydrocarbons such as crude oil, aromatic hydrocarbons, n-alkanes, aliphatic hydrocarbons, asphaltenes, naphthenes, and other petroleum products. This property of biosurfactant is very important as biofilms are of great concern due to their impact on the environment, public health, and industries worldwide. This work also includes several advanced molecular methods that can be used to enhance the production of biosurfactants by the microorganisms studied.}, } @article {pmid35579148, year = {2023}, author = {Saraswathi, N and Girigoswami, K and Divya, KC and Kumar, SG and Girigoswami, A}, title = {Degree of Gelatination on Ag-Nanoparticles to Inactivate Multi-drug Resistant Bacterial Biofilm Isolated from Sewage Treatment Plant.}, journal = {Current drug delivery}, volume = {20}, number = {5}, pages = {566-574}, doi = {10.2174/1567201819666220509160432}, pmid = {35579148}, issn = {1875-5704}, mesh = {Humans ; *Sewage ; *Metal Nanoparticles/chemistry ; Silver/pharmacology/chemistry ; Gelatin ; Anti-Bacterial Agents/chemistry ; Biofilms ; Pseudomonas aeruginosa ; Microbial Sensitivity Tests ; }, abstract = {INTRODUCTION: Overuse and improper dosage of antibiotics have generated antimicrobial resistance (AMR) worldwide. Pseudomonas aeruginosa (PA), a well-known bacterial strain can establish MDR leading to a variety of infections in humans. Furthermore, these PA strains hold the ability to form biofilms by generating extracellular polymeric substances on the surface of medical tools and critical care units. To supersede the infectious effect of MDR organisms, silver nanoparticles have been known to be the choice.

MATERIALS AND METHODS: Hence, the present study concentrates on the engineering of varying concentrations of gelatin-based polymeric hydrogel embedded with silver nanoparticles (G-AgNPs) for controlled bactericidal activity against MDR PA biofilms. Biofilms formation by MDR PA was confirmed microscopically and spectroscopy was taken as a tool to characterize and analyze the efficacy at every stage of experiments.

RESULTS: When MDR PA biofilms were treated with G-AgNPs prepared with 5 % gelatin concentration (AgNP3), they exhibited superior bactericidal activity. Furthermore, a dose-dependent study showed that 800 nM of AgNP3 could inhibit the growth of MDR PA.

CONCLUSION: Hence it can be concluded that silver nanoparticles synthesized in the presence of 5% gelatin can act as a bactericidal agent in the inactivation of MDR PA biofilms, thereby controlling the infections caused by these biofilms.}, } @article {pmid35578895, year = {2022}, author = {Rosca, AS and Castro, J and Sousa, LGV and França, A and Vaneechoutte, M and Cerca, N}, title = {In vitro interactions within a biofilm containing three species found in bacterial vaginosis (BV) support the higher antimicrobial tolerance associated with BV recurrence.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {8}, pages = {2183-2190}, doi = {10.1093/jac/dkac155}, pmid = {35578895}, issn = {1460-2091}, support = {//Portuguese Foundation for Science and Technology/ ; PTDC/BIA-MIC/28271/2017//FCT/ ; }, mesh = {Actinobacteria ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Bacteria ; Biofilms ; Clindamycin/pharmacology ; Female ; Gardnerella vaginalis/genetics ; Humans ; In Situ Hybridization, Fluorescence ; Metronidazole/pharmacology ; Vagina/microbiology ; *Vaginosis, Bacterial/microbiology ; }, abstract = {BACKGROUND: Bacterial vaginosis (BV), the most common cause of vaginal discharge, is characterized by the presence of a polymicrobial biofilm on the vaginal epithelium, formed primarily by Gardnerella spp., but also other anaerobic species. Interactions between bacteria in multi-species biofilms are likely to contribute to increased virulence and to enhanced antimicrobial tolerance observed in vivo. However, functional studies addressing this question are lacking.

OBJECTIVES: To gain insights into the role that interactions between BV-associated species in multi-species BV biofilms might have on antimicrobial tolerance, single- and triple-species biofilms formed by Gardnerella vaginalis, Fannyhessea (Atopobium) vaginae and Peptostreptococcus anaerobius were characterized, before and after metronidazole or clindamycin treatment.

METHODS: Total biofilm biomass, total cells and cfu counts prior to and after antibiotic treatment were first determined. In addition, bacterial populations in the triple-species biofilms were also quantified by quantitative PCR (qPCR) and peptide nucleic acid (PNA) fluorescence in situ hybridization (FISH).

RESULTS: Despite the effect observed in single-species biofilms, neither metronidazole nor clindamycin was effective in reducing triple-species biofilm biomass. Similar results were obtained when evaluating the number of total or culturable cells. Interestingly, despite differences between strain susceptibilities to antibiotics, the composition of the triple-species biofilms was not strongly affected by antibiotics.

CONCLUSIONS: Taken together, these results strengthen the idea that, when co-incubated, bacteria can interact synergistically, leading to increased tolerance to antimicrobial therapy, which helps explain the observed clinically high BV recurrence rates.}, } @article {pmid35576698, year = {2022}, author = {Das, A and Kundu, S and Gupta, M and Mukherjee, A}, title = {Guar gum propionate-kojic acid films for Escherichia coli biofilm disruption and simultaneous inhibition of planktonic growth.}, journal = {International journal of biological macromolecules}, volume = {211}, number = {}, pages = {57-73}, doi = {10.1016/j.ijbiomac.2022.05.052}, pmid = {35576698}, issn = {1879-0003}, mesh = {Adult ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; *Escherichia coli ; Galactans/chemistry/pharmacology ; Humans ; Mannans/chemistry/pharmacology ; Plankton ; Plant Gums/chemistry/pharmacology ; *Propionates ; Pyrones ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Nosocomial bacterial infections associated with biofilms inspire to explore newer bactericidal strategy with eco-friendly biomaterials as sustainable alternatives. In this research work, we successfully developed bio-safe films from kojic acid(KA) and guar gum propionate(GGP) for Escherichia coli biofilm disruption and planktonic cell killing. High DS(degree of substitution = 1.52) GGP was synthesized from guar gum (GG)assisted by chaotropic ions at room-temperature. Biopolymers were routinely characterized in CHN analyzer, FT-IR, TGA and XRD analysis. KA loaded GGP films were prepared by cross-linking the molecules in presence of epichlorhydrin and two different percentages of KA were employed. Film physical and tensile properties were systematically evaluated and optimized. Water vapour permeability (WVP) and tensile strength of final film GGPFK10 were recorded at 0.741 ± 0.09gmm[-1]kPa[-1]h[-1] and 19.23 MPa. KA release from GGP matrix followed controlled diffusion process. MIC of GGP was 130 μg/mL and zone of inhibition of GGPFK10 was confirmed at 16.1 mm. SEM experiments disclosed the absence of pili-like structures with squeezed and elongated cellular morphology in dead planktonic cells. Disruption of biofilms was experimented in detail by CV assay, fluorescent, light microscopic and SEM studies. The film showed excellent cell-viability on human adult dermal fibroblast (HADF)cell-line. Overall, the biosafe film would be a potent antibacterial device for treating infections against E.coli biofilms and planktonic cells.}, } @article {pmid35576062, year = {2022}, author = {Gurler, H and Findik, A and Sezener, MG}, title = {Determination of antibiotic resistance profiles and biofilm production of Staphylococcus spp. isolated from Anatolian water buffalo milk with subclinical mastitis.}, journal = {Polish journal of veterinary sciences}, volume = {25}, number = {1}, pages = {51-59}, doi = {10.24425/pjvs.2022.140840}, pmid = {35576062}, issn = {2300-2557}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Buffaloes ; Cattle ; *Cattle Diseases ; Drug Resistance, Microbial ; Female ; *Mastitis, Bovine ; Milk ; *Staphylococcal Infections/veterinary ; Staphylococcus/genetics ; Staphylococcus aureus ; }, abstract = {Mastitis is one of the most crucial diseases of dairy animals. Especially subclinical mastitis (SCM) has negative impacts on of dairy economy in term of reducing milk quality and quantity also premature culling and cost of therapy. Staphylococci are important etiological agents in SCM. The aim of the study was to investigate the biofilm production and antibiotic resistance profiles of Staphylococcus spp. other than S. aureus isolated from milks of Anatolian water buffalo with subclinical mastitis. Twenty-two coagulase negative staphylococci (CNS) identified phenotypically were also identified with PCR as Staphylococcus spp. other than S. aureus. Biofilm productions were investigated both by Congo Red Agar Method and PCR. The antibiotic resistance profiles of the isolates were determined by Disc Diffusion Method and they were antibiotyped. Only three (13.6%) isolates were biofilm positive both phenotypically and genotypically. All isolates except for two were resistant against at least two antibiotics. Multidrug-resistance among the isolates was low (13.6%). Antibiotyping results showed that the similarities among the strains were between 30-100%. Genotyping of the strains revealed that a genetic heterogeneity was found among CNS isolates and their similarities were between 43% and 93%. In conclusion, CNS isolates identified as subclinical mastitis agents in buffaloes showed a high antibiotic resistance profile especially against oxacillin and vancomycin. Further studies should be conducted to investigate new mechanisms and/or genes responsible for antibiotic resistance in buffaloes.}, } @article {pmid35575526, year = {2022}, author = {Ma, Y and Hasan, Z and Huang, J and Chen, J and Ho, CL}, title = {Measuring the Migration and Biofilm Formation of Various Bacteria.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {183}, pages = {}, doi = {10.3791/63595}, pmid = {35575526}, issn = {1940-087X}, mesh = {Animals ; Biofilms ; *Enterococcus faecalis ; Rats ; Rats, Sprague-Dawley ; *Staphylococcus ; }, abstract = {As microbes that thrive in the host body primarily have adaptive abilities that facilitate their survival, methods for classifying and identifying their nature would be beneficial in facilitating their characterization. Currently, most studies focus only on one specific characterization method; however, the isolation and identification of microorganisms from the host is a continuous process and usually requires several combinatorial characterization methods. Herein, we describe methods of identifying the microbial biofilm-forming ability, the microbial respiration state, and their chemotaxis behavior. The methods are used to identify five microbes, three of which were isolated from the bone tissue of Sprague-Dawley (SD) rats (Corynebacterium stationis, Staphylococcus cohnii subsp. urealyticus, and Enterococcus faecalis) and two from the American Type Culture Collection (ATCC)-Staphylococcus aureus ATCC 25923 and Enterococcus faecalis V583. The microbes isolated from the SD rat bone tissue include the gram-positive microbes. These microbes have adapted to thrive under stressful and nutrient-limiting environments within the bone matrix. This article aims to provide the readers with the specific know-how of determining the nature and behavior of the isolated microbes within a laboratory setting.}, } @article {pmid35575506, year = {2022}, author = {Ham, SY and Kim, HS and Cha, E and Lim, T and Byun, Y and Park, HD}, title = {Raffinose Inhibits Streptococcus mutans Biofilm Formation by Targeting Glucosyltransferase.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0207621}, pmid = {35575506}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Biological Products ; *Dental Caries/prevention & control ; Dental Materials/metabolism/pharmacology ; Glucans ; Glucosyltransferases/genetics/metabolism ; Humans ; Raffinose/metabolism/pharmacology ; Streptococcus mutans/metabolism ; }, abstract = {Streptococcus mutans is a representative biofilm-forming bacterium that causes dental caries through glucosyltransferase (GTF) activity. Glucans are synthesized from sucrose by GTFs and provide binding sites for S. mutans to adhere tightly to the tooth enamel. Therefore, if a novel compound that interferes with GTF function is developed, biofilm formation control in S. mutans would be possible. We discovered that raffinose, an oligosaccharide from natural products, strongly inhibited biofilm formation, GTF-related gene expression, and glucan production. Furthermore, biofilm inhibition on saliva-coated hydroxyapatite discs through the reduction of bacterial adhesion indicated the applicability of raffinose in oral health. These effects of raffinose appear to be due to its ability to modulate GTF activity in S. mutans. Hence, raffinose may be considered an antibiofilm agent for use as a substance for oral supplies and dental materials to prevent dental caries. IMPORTANCE Dental caries is the most prevalent infectious disease and is expensive to manage. Dental biofilms can be eliminated via mechanical treatment or inhibited using antibiotics. However, bacteria that are not entirely removed or are resistant to antibiotics can still form biofilms. In this study, we found that raffinose inhibited biofilm formation by S. mutans, a causative agent of dental caries, possibly through binding to GtfC. Our findings support the notion that biofilm inhibition by raffinose can be exerted by interference with GTF function, compensating for the shortcomings of existing commercialized antibiofilm methods. Furthermore, raffinose is an ingredient derived from natural products and can be safely utilized in humans; it has no smell and tastes sweet. Therefore, raffinose, which can control S. mutans biofilm formation, has been suggested as a substance for oral supplies and dental materials to prevent dental caries.}, } @article {pmid35575497, year = {2022}, author = {Shmidov, E and Lebenthal-Loinger, I and Roth, S and Karako-Lampert, S and Zander, I and Shoshani, S and Danielli, A and Banin, E}, title = {PrrT/A, a Pseudomonas aeruginosa Bacterial Encoded Toxin-Antitoxin System Involved in Prophage Regulation and Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0118222}, pmid = {35575497}, issn = {2165-0497}, mesh = {*Antitoxins/genetics/metabolism ; Bacteria/metabolism ; Bacterial Proteins/genetics/metabolism ; *Bacterial Toxins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Prophages/genetics ; Pseudomonas aeruginosa/genetics/metabolism ; *Toxin-Antitoxin Systems/genetics ; }, abstract = {Toxin-antitoxin (TA) systems are genetic modules that consist of a stable protein-toxin and an unstable antitoxin that neutralizes the toxic effect. In type II TA systems, the antitoxin is a protein that inhibits the toxin by direct binding. Type II TA systems, whose roles and functions are under intensive study, are highly distributed among bacterial chromosomes. Here, we identified and characterized a novel type II TA system PrrT/A encoded in the chromosome of the clinical isolate 39016 of the opportunistic pathogen Pseudomonas aeruginosa. We have shown that the PrrT/A system exhibits classical type II TA characteristics and novel regulatory properties. Following deletion of the prrA antitoxin, we discovered that the system is involved in a range of processes including (i) biofilm and motility, (ii) reduced prophage induction and bacteriophage production, and (iii) increased fitness for aminoglycosides. Taken together, these results highlight the importance of this toxin-antitoxin system to key physiological traits in P. aeruginosa. IMPORTANCE The functions attributed to bacterial TA systems are controversial and remain largely unknown. Our study suggests new insights into the potential functions of bacterial TA systems. We reveal that a chromosome-encoded TA system can regulate biofilm and motility, antibiotic resistance, prophage gene expression, and phage production. The latter presents a thus far unreported function of bacterial TA systems. In addition, with the emergence of antimicrobial-resistant bacteria, especially with the rising of P. aeruginosa resistant strains, the investigation of TA systems is critical as it may account for potential new targets against the resistant strains.}, } @article {pmid35575383, year = {2022}, author = {Peng, J and Xie, S and Huang, K and Ran, P and Wei, J and Zhang, Z and Li, X}, title = {Nitric oxide-propelled nanomotors for bacterial biofilm elimination and endotoxin removal to treat infected burn wounds.}, journal = {Journal of materials chemistry. B}, volume = {10}, number = {22}, pages = {4189-4202}, doi = {10.1039/d2tb00555g}, pmid = {35575383}, issn = {2050-7518}, mesh = {Animals ; Bacteria ; Biofilms ; *Burns/drug therapy ; Endotoxins/pharmacology ; Lipopolysaccharides ; Mice ; Nitric Oxide/pharmacology ; Pseudomonas aeruginosa ; *Wound Infection/drug therapy/microbiology ; }, abstract = {Biofilm infection is regarded as a major contributing factor to the failure of burn treatment and a persistent inflammatory state delays healing and leads to the formation of chronic wounds. Herein, self-propelled nanomotors (NMs) are proposed to enhance biofilm infiltration, bacterial destruction, and endotoxin clearance to accelerate the healing of infected burn wounds. Janus nanoparticles (NPs) were prepared through partially coating Fe3O4 NPs with polydopamine (PDA) layers, and then polymyxin B (PMB) and thiolated nitric oxide (SNO) donors were separately grafted onto the Janus NPs to obtain IO@PMB-SNO NMs. In response to elevated glutathione (GSH) levels in biofilms, NO generation from one side of the Janus NPs leads to self-propelled motion and deep infiltration into biofilms. The local release of NO could destroy bacteria inside the biofilm, which provides a non-antibiotic antibiofilm approach without the development of drug resistance. In addition to intrinsic antibacterial effects, the PMB grafts preferentially bind with bacteria and the active motion enhances lipopolysaccharide (LPS) clearance and then significantly attenuates the production of inflammatory cytokines and reactive oxide species by macrophages. Partial-thickness burn wounds were established on mice and infected with P. aeruginosa, and NM treatment almost fully destroyed the bacteria in the wounds. IO@PMB-SNO NMs absorb LPS and remove it from the wounds under a magnetic field, which downregulates the interleukin-6 and tumor necrosis factor-α levels in tissues. The infected wounds were completely healed with the deposition and arrangement of collagen fibers and the generation of skin features similar to those of normal skin. Thus, IO@PMB-SNO NMs achieved multiple-mode effects, including GSH-triggered NO release and self-propelled motion, the NO-induced non-antibiotic elimination of biofilms and bacteria, and PMB-induced endotoxin removal. This study offers a feasible strategy, with integrated antibiofilm and anti-inflammatory effects, for accelerating the healing of infected burn wounds.}, } @article {pmid35575359, year = {2022}, author = {Xue, R and Chu, X and Yang, F and Liu, Z and Yin, L and Tang, H}, title = {Imidazolium-Based Polypeptide Coating with a Synergistic Antibacterial Effect and a Biofilm-Responsive Property.}, journal = {ACS macro letters}, volume = {11}, number = {3}, pages = {387-393}, doi = {10.1021/acsmacrolett.2c00017}, pmid = {35575359}, issn = {2161-1653}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Coated Materials, Biocompatible/chemistry ; *Fosfomycin/pharmacology ; Mammals ; Peptides/pharmacology ; }, abstract = {Surface modification with cationic polymer coatings represented an important strategy to address the medical device-related infection issues. However, limited antibacterial activities and high cytotoxicity have hampered their development. Herein, we report a facile method to enhance the surface antibacterial activity by construction of an imidazolium-based polypeptide with fosfomycin counteranions (i.e., S4-PIL-FS). The polypeptide coating displayed a synergistic antibacterial effect from the combination of membrane disruption and inhibition of initial cell wall synthesis, leading to higher in vitro and in vivo surface antibacterial activities than cationic polypeptide or fosfomycin sodium alone. S4-PIL-FS also showed a decrease in the hemolytic ratio and cytotoxicity toward different mammalian cells. Moreover, we observed an interesting biofilm-responsive property of S4-PIL-FS originating from the esterase-induced cleavages of side-chain ester bonds that enabled an antibiofilm property of the cationic polypeptide coating.}, } @article {pmid35574689, year = {2022}, author = {Almeida, JCR and Bega, JMM and Leite, LS and de Oliveira, JN and Albertin, LL and Matsumoto, T}, title = {Membrane aerated biofilm reactor in recirculating aquaculture system for effluent treatment.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-13}, doi = {10.1080/09593330.2022.2078674}, pmid = {35574689}, issn = {1479-487X}, abstract = {The implementation of fish farming has been increasing worldwide over the last decades, as well the search for alternative production systems and the treatment of their generated effluent. Recirculating Aquaculture System (RAS) is a compact solution for future intensive fish farming. However, few configurations of treatment technologies were tested in RAS, such as systems with a Membrane Aerated Biofilm Reactor (MABR). In this scene, this study aimed to evaluate the RAS effluent treatment efficiency device for intensive Nile tilapia (Oreochromis niloticus) production, the fish species most cultivated worldwide. The novel RAS configuration was composed of a cultivation tank (CT), a Column Settler, and a MABR. The RAS performance was evaluated by pH, temperature, turbidity, dissolved oxygen (DO), total nitrogen (TN), ammonia, nitrite, nitrate, total solids (TS), and chemical oxygen demand (COD). The obtained results in average values for temperature, pH, and DO inside the CT were 25.22 ± 1.88°C, 7.61 ± 0.33, and 3.80 ± 1.30 mg L[-1], respectively, as ideal for tilapias survival. Average removal efficiencies found in the RAS for turbidity, COD, TN, nitrite, nitrate, ammonia, and TS were 50.0, 40.5, 11.7, 40.2, 13.1, 35.0, and 11.4%, respectively. Overall, we observed removals for all parameters studied, with good results, particularly, for COD, turbidity, nitrite, and ammonia. The evaluated system proved an effective alternative for water reuse in RAS capable of maintaining water quality characteristics within the recommended values for fish farming.}, } @article {pmid35573801, year = {2022}, author = {Cho, JY and Liu, R and Hsiao, A}, title = {Microbiota-Associated Biofilm Regulation Leads to Vibrio cholerae Resistance Against Intestinal Environmental Stress.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {861677}, pmid = {35573801}, issn = {2235-2988}, support = {R01 AI157106/AI/NIAID NIH HHS/United States ; R35 GM124724/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biofilms ; *Cholera ; Disease Susceptibility ; Gene Expression Regulation, Bacterial ; Intestines ; Mice ; *Microbiota ; *Vibrio cholerae/genetics/metabolism ; }, abstract = {The commensal microbes of the gut microbiota make important contributions to host defense against gastrointestinal pathogens, including Vibrio cholerae, the etiologic agent of cholera. As interindividual microbiota variation drives individual differences in infection susceptibility, we examined both host and V. cholerae gene expression during infection of suckling mice transplanted with different model human commensal communities, including an infection-susceptible configuration representing communities damaged by recurrent diarrhea and malnutrition in cholera endemic areas and a representative infection-resistant microbiota characteristic of healthy individuals. In comparison to colonization of animals with resistant microbiota, animals bearing susceptible microbiota challenged with V. cholerae downregulate genes associated with generation of reactive oxygen/nitrogen stress, while V. cholerae in these animals upregulates biofilm-associated genes. We show that V. cholerae in susceptible microbe infection contexts are more resistant to oxidative stress and inhibitory bile metabolites generated by the action of commensal microbes and that both phenotypes are dependent on biofilm-associated genes, including vpsL. We also show that susceptible and infection-resistant microbes drive different bile acid compositions in vivo by the action of bile salt hydrolase enzymes. Taken together, these findings provide a better understanding of how the microbiota uses multiple mechanisms to modulate the infection-associated host environment encountered by V. cholerae, leading to commensal-dependent differences in infection susceptibility.}, } @article {pmid35573794, year = {2022}, author = {Ommen, P and Hansen, L and Hansen, BK and Vu-Quang, H and Kjems, J and Meyer, RL}, title = {Aptamer-Targeted Drug Delivery for Staphylococcus aureus Biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {814340}, pmid = {35573794}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Drug Delivery Systems ; Humans ; Liposomes ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; *Staphylococcus aureus/genetics ; }, abstract = {Treatment of Staphylococcus aureus biofilm infections using conventional antibiotic therapy is challenging as only doses that are sublethal to the biofilm can be administered safely to patients. A potential solution to this challenge is targeted drug delivery. In this study, we tailored an aptamer-targeted liposomal drug delivery system for accumulation and delivery of antibiotics locally in S. aureus biofilm. In our search for a suitable targeting ligand, we identified six DNA aptamers that bound to S. aureus cells in biofilms, and we demonstrated that one of these aptamers could facilitate accumulation of liposomes around S. aureus cells inside the biofilm. Aptamer-targeted liposomes encapsulating a combination of vancomycin and rifampicin were able to eradicate S. aureus biofilm upon 24 h of treatment in vitro. Our results point to that aptamer-targeted drug delivery of antibiotics is a potential new strategy for treatment of S. aureus biofilm infections.}, } @article {pmid35572854, year = {2022}, author = {Sun, H and Chan, Y and Li, X and Xu, R and Zhang, Z and Hu, X and Wu, F and Deng, F and Yu, X}, title = {Multi-omics analysis of oral bacterial biofilm on titanium oxide nanostructure modified implant surface: In vivo sequencing-based pilot study in beagle dogs.}, journal = {Materials today. Bio}, volume = {15}, number = {}, pages = {100275}, pmid = {35572854}, issn = {2590-0064}, abstract = {Peri-implantitis, the major cause of implant failure, is an inflammatory destructive disease due to the dysbiotic polymicrobial communities at the peri-implant sites. Therefore, it is highly warranted to develop the implant materials with antimicrobial properties and investigate their effects on oral microbiota. However, most of the relevant studies were performed in vitro, and insufficient to provide the comprehensive assessment of the antimicrobial capacity of the implant materials in vivo. Herein, we introduce an innovative approach to evaluate the in vivo antibacterial properties of the most commonly used implant materials, titanium with different nanostructured surfaces, and investigate their antibacterial mechanism via the next-generation sequencing (NGS) technology. We firstly prepared the titanium implants with three different surfaces, i) mechanical polishing (MP), ii) TiO2 nanotubes (NT) and iii) nanophase calcium phosphate embedded to TiO2 nanotubes (NTN), and then characterized them using scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM) and surface hydrophilicity analysis. Afterwards, the implants were placed in the beagle dogs' mouths to replace the pre-extracted premolar and molar teeth for eight weeks through implant surgery. The supra- and sub-mucosal plaques were collected and subjected to 16S rRNA gene/RNA sequencing and data analysis. It was found that the nanostructured surfaces in NT and NTN groups showed significantly increased roughness and decreased water contact angles compared to the MP group, while the XPS data further confirmed the successful modifications of TiO2 nanotubes and the subsequent deposition of nanophase calcium phosphate. Notably, the nanostructured surfaces in NT and NTN groups had limited impact on the diversity and community structure of oral microbiota according to the 16S rRNA sequencing results, and the nanostructures in NTN group could down-regulate the genes associated with localization and locomotion based on Gene Ontology (GO) terms enrichment analysis. Moreover, the differentially expressed genes (DEGs) were associated with microbial metabolism, protein synthesis and bacterial invasion of epithelial cells. Taken together, this study provides a new strategy to evaluate the antibacterial properties of the biomedical materials in vivo via the high-throughput sequencing and bioinformatic approaches, revealing the differences of the composition and functional gene expressions in the supra- and sub-mucosal microbiome.}, } @article {pmid35572695, year = {2022}, author = {Li, RJ and Qin, C and Huang, GR and Liao, LJ and Mo, XQ and Huang, YQ}, title = {Phillygenin Inhibits Helicobacter pylori by Preventing Biofilm Formation and Inducing ATP Leakage.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {863624}, pmid = {35572695}, issn = {1664-302X}, abstract = {With the widespread use and abuse of antibiotics, Helicobacter pylori (H. pylori) has become seriously drug resistant. The development of new antibiotics is an important way to solve H. pylori's drug resistance. Screening antibacterial ingredients from natural products is a convenient way to develop new antibiotics. Phillygenin, an effective antibacterial component, was selected from the natural product, forsythia, in this study. Its minimal inhibitory concentration (MIC) for 18 H. pylori strains was 16-32 μg/ml. The minimum bactericidal concentration (MBC) of H. pylori G27 was 128 μg/ml; the higher the drug concentration and the longer the time, the better the sterilization effect. It was non-toxic to gastric epithelial cell (GES)-1 and BGC823 cells at the concentration of 100 μg/ml. It presented a better antibacterial effect on H. pylori in an acidic environment, and after 24 days of induction on H. pylori with 1/4 MIC of phillygenin, no change was found in the MIC of H. pylori. In the mechanism of action, phillygenin could cause ATP leakage and inhibit the biofilm formation; the latter was associated with the regulation of spoT and Hp1174 genes. In addition, phillygenin could regulate the genes of Nhac, caggamma, MATE, MdoB, flagellinA, and lptB, leading to the weakening of H. pylori's acid resistance and virulence, the diminishing of H. pylori's capacity for drug efflux, H. pylori's DNA methylation, the initiation of human immune response, and the ATP leakage of H. pylori, thus accelerating the death of H. pylori. In conclusion, phillygenin was a main ingredient inhibiting H. pylori in Forsythia suspensa, with a good antibacterial activity, high safety, strong specificity, better antibacterial effect under acidic conditions, and low risk of resistance development by H. pylori. Its mechanism of action was mainly associated with inhibiting the biofilm formation and resulting in ATP leakage. In addition, phillygenin was shown to be able to reduce the acid resistance and virulence of H. pylori.}, } @article {pmid35572468, year = {2022}, author = {Demir, B and Taylor, A and Broughton, RM and Huang, TS and Bozack, MJ and Worley, SD}, title = {N-halamine surface coating for mitigation of biofilm and microbial contamination in water systems for space travel.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100076}, pmid = {35572468}, issn = {2590-2075}, abstract = {A copolymer termed HASL produced from monomeric units of 2-acrylamido-2-methyl-1-(5-methylhydantoinyl)propane (HA) and of 3-(trimethoxysilyl)propyl methacrylate (SL) has been coated onto stainless steel and Inconel™ substrates, which upon halogenation with either aqueous oxidative chlorine or bromine, became antimicrobial. It has been demonstrated that the halogenated stainless steel and Inconel™ substrates were effective in producing 6 to 7 log inactivations of Staphylococcus aureus and Escherichia coli O157:H7 within about 10 min, and in prevention of Pseudomonas aeruginosa biofilm formation over a period of at least 72 h on the stainless steel substrates. Upon loss of halogen, the HASL coating could be re-charged with aqueous halogen. The HASL coating was easily applied to the substrates via a simple dip-coating method and was reasonably stable to contact with water. Both chlorinated substrates could be loaded with at least 6 × 10[16] oxidative Cl atoms per cm[2] and maintained a loading of greater than 1 × 10[16] chlorine atoms per cm[2] for a period of 3-7 days while agitated in aqueous solution. After loss of chlorine to a level below 1 × 10[16] atoms per cm[2], the substrates could be recharged to the 6 × 10[16] Cl atoms per cm[2] level for at least 5 times over a 28 day period. The new antimicrobial coating technology has potential for use in a variety of important applications, particularly for water treatment and storage on spacecraft.}, } @article {pmid35570462, year = {2022}, author = {Fortune, GT and Oliveira, NM and Goldstein, RE}, title = {Biofilm Growth under Elastic Confinement.}, journal = {Physical review letters}, volume = {128}, number = {17}, pages = {178102}, doi = {10.1103/PhysRevLett.128.178102}, pmid = {35570462}, issn = {1079-7114}, mesh = {*Bacillus subtilis ; *Biofilms ; Extracellular Matrix ; }, abstract = {Bacteria often form surface-bound communities, embedded in a self-produced extracellular matrix, called biofilms. Quantitative studies of bioflim growth have typically focused on unconfined expansion above solid or semisolid surfaces, leading to exponential radial growth. This geometry does not accurately reflect the natural or biomedical contexts in which biofilms grow in confined spaces. Here, we consider one of the simplest confined geometries: a biofilm growing laterally in the space between a solid surface and an overlying elastic sheet. A poroelastic framework is utilized to derive the radial growth rate of the biofilm; it reveals an additional self-similar expansion regime, governed by the Poisson's ratio of the matrix, leading to a finite maximum radius, consistent with our experimental observations of growing Bacillus subtilis biofilms confined by polydimethylsiloxane.}, } @article {pmid35569716, year = {2022}, author = {Rana, MS and Prajapati, SK}, title = {Mixotrophic microalgal-biofilm reactor augmenting biomass and biofuel productivity.}, journal = {Bioresource technology}, volume = {356}, number = {}, pages = {127306}, doi = {10.1016/j.biortech.2022.127306}, pmid = {35569716}, issn = {1873-2976}, mesh = {Biofilms ; Biofuels ; Biomass ; *Chlorella ; Glycerol ; *Microalgae ; }, abstract = {The present work aimed to evaluate the mixotrophic growth of Chlorella pyrenoidosa in a microalgal-biofilm reactor (MBR) using waste glycerol as an organic carbon source. The biomass productivity of C. pyrenoidosa (10.14 g m[-2] d[-1]) under the mixotrophic mode was remarkably higher than that observed during the phototrophic mode (4.16 g m[-2] d[-1]), under similar incubation conditions. The hydraulic retention time (HRT) of 6 d was found optimal for the higher productivity of microalgae in the MBR. Notably, based on biofuel quality, mixotrophically grown microalgal biomass was noted to have better suitability for biomethane production compared to biodiesel. Besides, up to 98.09, 75.74, and 55.86% removal of phosphate, nitrate, and COD, respectively, was recorded within 6 d under mixotrophic growth. Overall, the present findings magnificently demonstrate the efficient recycling of waste glycerol for higher biomass production coupled with phycoremediation using mixotrophic MBR.}, } @article {pmid35567892, year = {2022}, author = {Martinez-Malaxetxebarria, I and Girbau, C and Salazar-Sánchez, A and Baztarrika, I and Martínez-Ballesteros, I and Laorden, L and Alonso, R and Fernández-Astorga, A}, title = {Genetic characterization and biofilm formation of potentially pathogenic foodborne Arcobacter isolates.}, journal = {International journal of food microbiology}, volume = {373}, number = {}, pages = {109712}, doi = {10.1016/j.ijfoodmicro.2022.109712}, pmid = {35567892}, issn = {1879-3460}, mesh = {*Arcobacter ; Biofilms ; Food Microbiology ; Humans ; Meat ; Multilocus Sequence Typing ; }, abstract = {Various species of the genus Arcobacter are regarded as emerging food pathogens and can be cause of human gastroenteric illness, among others. In order to gain knowledge on the risk associated with the presence of arcobacters in retail foods, this study aimed to determine their presence in a variety of products; to evaluate the genetic diversity and the occurrence of virulence and biofilm-associated genes in the isolated strains; and to assess their biofilm activity on polystyrene, borosilicate and stainless steel. Arcobacters were detected in the 22.3% of the analysed samples and the 83 recovered isolates were identified as A. butzleri (n = 53), A. cryaerophilus (n = 24), A. skirrowii (n = 2), A. thereius (n = 3) and A. vitoriensis (n = 1). They were isolated from virtually all tested food types, but mostly from squids and turkey meat (contamination levels of 60% and 40%, respectively). MLST differentiated 68 STs, most of which were novel (89.7%) and represented by a single strain (86.9%). Five novel STs were detected in various isolates derived from seafood, and the statistical analysis revealed their potential association with that type of food product (p < 0,001). All the isolates except one harboured virulence-associated genes and the highest incidence was noted for A. butzleri. Nineteen isolates (23.5%) were able to form biofilms on the different surfaces tested and, of note; glass enhanced the adhesion ability of the majority of them (84.2%). The results highlight the role that common food products can have in the transmission of Arcobacter spp., the pathogenic potential of the different species, and the survival and growth ability of several of them on different food contact surfaces. Therefore, the study provides interesting information regarding the risk arcobacters may pose to human health and the food industry.}, } @article {pmid35567269, year = {2022}, author = {Gamal El-Din, MI and Youssef, FS and Altyar, AE and Ashour, ML}, title = {GC/MS Analyses of the Essential Oils Obtained from Different Jatropha Species, Their Discrimination Using Chemometric Analysis and Assessment of Their Antibacterial and Anti-Biofilm Activities.}, journal = {Plants (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {35567269}, issn = {2223-7747}, support = {RG-25-166-43//The Deanship of Scientific Research (DSR) at King Abdulaziz University (KAU), Jeddah, Saudi Arabia,/ ; }, abstract = {The essential oils of Jatropha intigrimma, J. roseae and J. gossypifolia (Euphorbiaceae) were analyzed employing GC/MS (Gas Chromatography coupled with Mass Spectrometry) analyses. A total of 95 volatile constituents were identified from J. intigrimma, J. gossypifolia and J. roseae essential oils, accounting for 91.61, 90.12, and 86.24%, respectively. Chemometric analysis using principal component analysis (PCA) based on the obtained GC data revealed the formation of three discriminant clusters due to the placement of the three Jatropha species in three different quadrants, highlighting the dissimilarity between them. Heneicosane, phytol, nonacosane, silphiperfol-6-ene, copaborneol, hexatriacontane, octadecamethyl-cyclononasiloxane, 9,12,15-Octadecatrienoic acid, methyl ester and methyl linoleate constitute the key markers for their differentiation. In vitro antibacterial activities of the essential oils were investigated at doses of 10 mg/mL against the Gram-negative anaerobe Escherichia coli using the agar well diffusion method and broth microdilution test. J. gossypifolia essential oil showed the most potent antimicrobial activity, demonstrating the largest inhibition zone (11.90 mm) and the least minimum inhibitory concentration (2.50 mg/mL), followed by the essential oil of J. intigrimma. The essential oils were evaluated for their anti-adhesion properties against the Gram-negative E. coli biofilm using a modified method of biofilm inhibition spectrophotometric assay. J. intigrimma essential oil showed the most potent biofilm inhibitory activity, demonstrating the least minimum biofilm inhibitory concentration (MBIC) of 31.25 µg/mL. In silico molecular docking performed within the active center of E. coli adhesion protein FimH showed that heneicosane, followed by cubebol and methyl linoleate, displayed the best fitting score. Thus, it can be concluded that the essential oils of J. gossypifolia and J. intigrimma leaves represent promising sources for antibacterial drugs with antibiofilm potential.}, } @article {pmid35565586, year = {2022}, author = {Xue, M and Fu, D and Hu, J and Shao, Y and Tu, J and Song, X and Qi, K}, title = {The Transcription Regulator YgeK Affects Biofilm Formation and Environmental Stress Resistance in Avian Pathogenic Escherichia coli.}, journal = {Animals : an open access journal from MDPI}, volume = {12}, number = {9}, pages = {}, pmid = {35565586}, issn = {2076-2615}, support = {jit-b-202154//Jinling Institute of Technology Scientific research start-up fund for high-end talents/ ; 31772707//National Natural Science Foundation of China/ ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is one of the most common pathogens in poultry and a potential gene source of human extraintestinal pathogenic E. coli (ExPEC), leading to serious economic losses in the poultry industry and public health concerns. Exploring the pathogenic mechanisms underpinning APEC and the identification of new targets for disease prevention and treatment are warranted. YgeK is a transcriptional regulator in APEC and is localized to the type III secretion system 2 of E. coli. In our previous work, the transcription factor ygeK significantly affected APEC flagella formation, bacterial motility, serum sensitivity, adhesion, and virulence. To further explore ygeK functions, we evaluated its influence on APEC biofilm formation and resistance to environmental stress. Our results showed that ygeK inactivation decreased biofilm formation and reduced bacterial resistance to environmental stresses, including acid and oxidative stress. In addition, the multi-level regulation of ygeK in APEC was analyzed using proteomics, and associations between differentially expressed proteins and the key targets of ygeK were investigated. Overall, we identified ygeK's new function in APEC. These have led us to better understand the transcriptional regulatory ygeK and provide new clues about the pathogenicity of APEC.}, } @article {pmid35564028, year = {2022}, author = {Li, Y and Dong, R and Ma, L and Qian, Y and Liu, Z}, title = {Combined Anti-Biofilm Enzymes Strengthen the Eradicate Effect of Vibrio parahaemolyticus Biofilm: Mechanism on cpsA-J Expression and Application on Different Carriers.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {35564028}, issn = {2304-8158}, support = {31972141//National Natural Science Foundation of China/ ; 2021YFD2100504//National Key Research and Development Program/ ; }, abstract = {Vibrio parahaemolyticus is a human foodborne pathogen, and it can form a mature biofilm on food and food contact surfaces to enhance their resistance to antibacterial agents. In this study, the effect of anti-biofilm enzymes (combined lipase, cellulase and proteinase K) on the inhibition and eradication of pathogen biofilm was evaluated. The biofilm content of V. parahaemolyticus showed the highest level at the incubation time of 24 h, and the combined enzymes significantly inhibited the biofilm's development. The biofilm's inhibition and eradication rate at an incubation time of 24 h was 89.7% and 66.9%, respectively. The confocal laser scanning microscopic images confirmed that the microcolonies' aggregation and the adhesion of biofilm were inhibited with the combined enzyme treatment. Furthermore, combined enzymes also decreased the concentration of exopolysaccharide (EPS) and disrupted the EPS matrix network, wherein the expression of the EPS-related gene, cpsA-J, was likewise suppressed. The combined enzymes showed an excellent inhibition effect of V. parahaemolyticus biofilm on different carriers, with the highest inhibition rate of 59.35% on nonrust steel plate. This study demonstrates that the combined enzyme of lipase, cellulase and proteinase K could be a novel candidate to overcome biofilm's problem of foodborne pathogens in the food industry.}, } @article {pmid35563985, year = {2022}, author = {Yi, Z and Xie, J}, title = {Genomic Analysis of Two Representative Strains of Shewanella putrefaciens Isolated from Bigeye Tuna: Biofilm and Spoilage-Associated Behavior.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {35563985}, issn = {2304-8158}, support = {31972142//National Natural Science Foundation of China/ ; 19DZ1207503//key project of Science and Technology Commission of Shanghai Municipality/ ; CARS-47//China Agriculture Research System of MOF and MARA/ ; 19DZ2284000//Shanghai Municipal Science and Technology Project to enhance the capabilities of the platform/ ; }, abstract = {Shewanella putrefaciens can cause the spoilage of seafood and shorten its shelf life. In this study, both strains of S. putrefaciens (YZ08 and YZ-J) isolated from spoiled bigeye tuna were subjected to in-depth phenotypic and genotypic characterization to better understand their roles in seafood spoilage. The complete genome sequences of strains YZ08 and YZ-J were reported. Unique genes of the two S. putrefaciens strains were identified by pan-genomic analysis. In vitro experiments revealed that YZ08 and YZ-J could adapt to various environmental stresses, including cold-shock temperature, pH, NaCl, and nutrient stresses. YZ08 was better at adapting to NaCl stress, and its genome possessed more NaCl stress-related genes compared with the YZ-J strain. YZ-J was a higher biofilm and exopolysaccharide producer than YZ08 at 4 and 30 °C, while YZ08 showed greater motility and enhanced capacity for biogenic amine metabolism, trimethylamine metabolism, and sulfur metabolism compared with YZ-J at both temperatures. That YZ08 produced low biofilm and exopolysaccharide contents and displayed high motility may be associated with the presence of more a greater number of genes encoding chemotaxis-related proteins (cheX) and low expression of the bpfA operon. This study provided novel molecular targets for the development of new antiseptic antisepsis strategies.}, } @article {pmid35563925, year = {2022}, author = {Shi, J and Li, SF and Feng, K and Han, SY and Hu, TG and Wu, H}, title = {Improving the Viability of Probiotics under Harsh Conditions by the Formation of Biofilm on Electrospun Nanofiber Mat.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {35563925}, issn = {2304-8158}, support = {No. 2020B0301030005//Guangdong Major Project of Basic and Applied Basic Research/ ; No. 2021A1515010765//Natural Science Foundation of Guangdong Province/ ; No. 2020B020226007//Key-Area Research and Development Program of Guangdong Province/ ; No. 2019B110210004//Collaborative Innovation Center for Sports of Guangdong Province/ ; }, abstract = {For improving probiotics' survivability under harsh conditions, this study used Lactiplantibacillus plantarum GIM1.648 as a model microorganism to investigate its ability to produce biofilms on electrospun ethyl cellulose nanofiber mats. SEM observations confirmed that biofilm was successfully formed on the nanofibers, with the latter being an excellent scaffold material. The optimal cultivation conditions for biofilm formation were MRS medium without Tween 80, a culture time of 36 h, a temperature of 30 °C, a pH of 6.5, and an inoculum concentration of 1% (v/v). The sessile cells in the biofilm exhibited improved gastrointestinal and thermal tolerance compared to the planktonic cells. Additionally, the RT-qPCR assay indicated that the luxS gene played a crucial role in biofilm formation, with its relative expression level being 8.7-fold higher compared to the planktonic cells. In conclusion, biofilm formation on electrospun nanofiber mat has great potential for improving the viability of probiotic cells under harsh conditions.}, } @article {pmid35563384, year = {2022}, author = {Gómez-Alonso, IS and Martínez-García, S and Betanzos-Cabrera, G and Juárez, E and Sarabia-León, MC and Herrera, MT and Gómez-Chávez, F and Sanchez-Torres, L and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino, J and Cancino-Diaz, JC}, title = {Low Concentration of the Neutrophil Proteases Cathepsin G, Cathepsin B, Proteinase-3 and Metalloproteinase-9 Induce Biofilm Formation in Non-Biofilm-Forming Staphylococcus epidermidis Isolates.}, journal = {International journal of molecular sciences}, volume = {23}, number = {9}, pages = {}, pmid = {35563384}, issn = {1422-0067}, support = {20221352SIP//Instituto Politécnico Nacional/ ; 20221193SIP//Instituto Politécnico Nacional/ ; }, mesh = {Animals ; Biofilms ; Cathepsin B ; Cathepsin G ; Metalloproteases ; Mice ; Myeloblastin ; *Neutrophils/metabolism ; *Peptide Hydrolases/metabolism ; *Staphylococcal Infections/microbiology ; *Staphylococcus epidermidis ; }, abstract = {Neutrophils play a crucial role in eliminating bacteria that invade the human body; however, cathepsin G can induce biofilm formation in a non-biofilm-forming Staphylococcus epidermidis 1457 strain, suggesting that neutrophil proteases may be involved in biofilm formation. Cathepsin G, cathepsin B, proteinase-3, and metalloproteinase-9 (MMP-9) from neutrophils were tested on the biofilm induction in commensal (skin isolated) and clinical non-biofilm-forming S. epidermidis isolates. From 81 isolates, 53 (74%) were aap+, icaA−, icaD− genotype, and without the capacity of biofilm formation under conditions of 1% glucose, 4% ethanol or 4% NaCl, but these 53 non-biofilm-forming isolates induced biofilm by the use of different neutrophil proteases. Of these, 62.3% induced biofilm with proteinase-3, 15% with cathepsin G, 10% with cathepsin B and 5% with MMP -9, where most of the protease-induced biofilm isolates were commensal strains (skin). In the biofilm formation kinetics analysis, the addition of phenylmethylsulfonyl fluoride (PMSF; a proteinase-3 inhibitor) showed that proteinase-3 participates in the cell aggregation stage of biofilm formation. A biofilm induced with proteinase-3 and DNAse-treated significantly reduced biofilm formation at an early time (initial adhesion stage of biofilm formation) compared to untreated proteinase-3-induced biofilm (p < 0.05). A catheter inoculated with a commensal (skin) non-biofilm-forming S. epidermidis isolate treated with proteinase-3 and another one without the enzyme were inserted into the back of a mouse. After 7 days of incubation period, the catheters were recovered and the number of grown bacteria was quantified, finding a higher amount of adhered proteinase-3-treated bacteria in the catheter than non-proteinase-3-treated bacteria (p < 0.05). Commensal non-biofilm-forming S. epidermidis in the presence of neutrophil cells significantly induced the biofilm formation when multiplicity of infection (MOI) 1:0.01 (neutrophil:bacteria) was used, but the addition of a cocktail of protease inhibitors impeded biofilm formation. A neutrophil:bacteria assay did not induce neutrophil extracellular traps (NETs). Our results suggest that neutrophils, in the presence of commensal non-biofilm-forming S. epidermidis, do not generate NETs formation. The effect of neutrophils is the production of proteases, and proteinase-3 releases bacterial DNA at the initial adhesion, favoring cell aggregation and subsequently leading to biofilm formation.}, } @article {pmid35562687, year = {2022}, author = {Yehia, FAA and Yousef, N and Askoura, M}, title = {Correction: Celastrol mitigates staphyloxanthin biosynthesis and biofilm formation in Staphylococcus aureus via targeting key regulators of virulence; in vitro and in vivo approach.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {130}, pmid = {35562687}, issn = {1471-2180}, } @article {pmid35561981, year = {2022}, author = {Li, A and Shi, C and Qian, S and Wang, Z and Zhao, S and Liu, Y and Xue, Z}, title = {Evaluation of antibiotic combination of Litsea cubeba essential oil on Vibrio parahaemolyticus inhibition mechanism and anti-biofilm ability.}, journal = {Microbial pathogenesis}, volume = {168}, number = {}, pages = {105574}, doi = {10.1016/j.micpath.2022.105574}, pmid = {35561981}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Litsea/chemistry ; *Oils, Volatile/pharmacology ; *Vibrio parahaemolyticus ; }, abstract = {Vibrio parahaemolyticus (V. parahaemolyticus) is a common pathogen in seafood. The use of antibiotics is a primary tool to prevent and control V. parahaemolyticus in the aquaculture industry. However, V. parahaemolyticus combats the damage caused by antibiotics by forming biofilms under certain conditions. In this study, we analyzed the antibacterial effect and the characteristics of V. parahaemolyticus by experimentally determining the minimum inhibitory concentration (MIC) and the fractional inhibitory concentration index (FICI) values of a combination of the Litsea cubeba essential oil (LCEO) and several commonly used V. parahaemolyticus antibiotics. The bactericidal effect of the essential oil alone and essential oil in combination with the antibiotics were evaluated with time-kill curves. The damage to cell membranes and cell walls were assessed by measuring the content of macromolecules and alkaline phosphatase (AKP) released into the supernatant using V. parahaemolyticus ATCC17802 as the experimental strain. The membrane structure was observed by transmission electron microscopy. The results showed that the MIC value of the LCEO was 1,024 μg/mL, and the LCEO FICI values in combination with tetracycline or oxytetracycline hydrochloride was 0.3125 and 0.75, respectively, indicating synergistic and additive effects. Moreover, LCEO inhibited the growth and promoted the removal of biofilms by reducing the content of hydrophobic and extracellular polysaccharides on the cell surface. This study provides a reference for studying the antibacterial activity of LCEO and the combination of antibiotics to prevent and control the formation of biofilms by V. parahaemolyticus.}, } @article {pmid35561821, year = {2022}, author = {Wang, YR and Li, KW and Wang, YX and Liu, XL and Mu, Y}, title = {Nutrient limitation regulates the properties of extracellular electron transfer and hydraulic shear resistance of electroactive biofilm.}, journal = {Environmental research}, volume = {212}, number = {Pt C}, pages = {113408}, doi = {10.1016/j.envres.2022.113408}, pmid = {35561821}, issn = {1096-0953}, mesh = {*Biofilms ; Electrons ; *Extracellular Polymeric Substance Matrix/metabolism ; *Geobacter/physiology ; }, abstract = {Understanding the roles of nutrient restriction in extracellular electron transfer (EET) and stability of mixed electroactive biofilm is essential in pollutant degradation and bioenergy production. However, the relevant studies are still limited so far. Herein, the effect of nutrient restriction on the EET pathways and stability of mixed electroactive biofilm was explored. It was found that the electroactive Pseudomonas and Geobacter genera were selectively enriched in the biofilms cultured under total nutrient and P-constrained conditions, and two EET pathways including direct and indirect were found, while Rhodopseudomonas genus was enriched in the N-constrained biofilm, which only had the direct EET pathway. Moreover, multiple analyses including 2D confocal Raman spectra revealed that P-constrained biofilm was rich in extracellular polymeric substances (EPS) especially for polysaccharide, presented a dense and uniform layered distribution, and had better stability than N-constrained biofilm with lower EPS and biofilm with heterostructures cultured under total nutrient conditions.}, } @article {pmid35561462, year = {2022}, author = {Zulkifli, M and Abu Hasan, H and Sheikh Abdullah, SR and Muhamad, MH}, title = {A review of ammonia removal using a biofilm-based reactor and its challenges.}, journal = {Journal of environmental management}, volume = {315}, number = {}, pages = {115162}, doi = {10.1016/j.jenvman.2022.115162}, pmid = {35561462}, issn = {1095-8630}, mesh = {*Ammonia/metabolism ; Bacteria/metabolism ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Humans ; Nitrates/metabolism ; Nitrification ; Nitrites ; Nitrogen/metabolism ; Wastewater/microbiology ; }, abstract = {Extensive growth of industries leads to uncontrolled ammonia releases to environment. This can result in significant degradation of the aquatic ecology as well as significant health concerns for humans. Knowing the mechanism of ammonia elimination is the simplest approach to comprehending it. Ammonia has been commonly converted to less hazardous substances either in the form of nitrate or nitrogen gas. Ammonia has been converted into nitrite by ammonia-oxidizing bacteria and further reduced to nitrate by nitrite-oxidizing bacteria in aerobic conditions. Denitrification takes place in an anoxic phase and nitrate is converted into nitrogen gas. It is challenging to remove ammonia by employing technologies that do not incur particularly high costs. Thus, this review paper is focused on biofilm reactors that utilize the nitrification process. Many research publications and patents on biofilm wastewater treatment have been published. However, only a tiny percentage of these projects are for full-scale applications, and the majority of the work was completed within the last few decades. The physicochemical approaches such as ammonia adsorption, coagulation-flocculation, and membrane separation, as well as conventional biological treatments including activated sludge, microalgae, and bacteria biofilm, are briefly addressed in this review paper. The effectiveness of biofilm reactors in removing ammonia was compared, and the microbes that effectively remove ammonia were thoroughly discussed. Overall, biofilm reactors can remove up to 99.7% ammonia from streams with a concentration in range of 16-900 mg/L. As many challenges were identified for ammonia removal using biofilm at a commercial scale, this study offers future perspectives on how to address the most pressing biofilm issues. This review may also improve our understanding of biofilm technologies for the removal of ammonia as well as polishing unit in wastewater treatment plants for the water reuse and recycling, supporting the circular economy concept.}, } @article {pmid35557687, year = {2022}, author = {Ganesh, PS and Veena, K and Senthil, R and Iswamy, K and Ponmalar, EM and Mariappan, V and Girija, ASS and Vadivelu, J and Nagarajan, S and Challabathula, D and Shankar, EM}, title = {Biofilm-Associated Agr and Sar Quorum Sensing Systems of Staphylococcus aureus Are Inhibited by 3-Hydroxybenzoic Acid Derived from Illicium verum.}, journal = {ACS omega}, volume = {7}, number = {17}, pages = {14653-14665}, pmid = {35557687}, issn = {2470-1343}, abstract = {Biofilm-producing Staphylococcus aureus (S. aureus) is less sensitive to conventional antibiotics than free-living planktonic cells. Here, we evaluated the antibiofilm activity of Illicium verum (I. verum) and one of its constituent compounds 3-hydroxybenzoic acid (3-HBA) against multi-drug-resistant S. aureus. We performed gas chromatography-mass spectroscopy (GC-MS) to identify the major constituents in the methanolic extract of I. verum. Ligand-receptor interactions were studied by molecular docking, and in vitro investigations were performed using crystal violet assay, spreading assay, hemolysis, proteolytic activity, and growth curve analysis. The methanolic extract of I. verum inhibited S. aureus at 4.8 mg/mL, and GC-MS analysis revealed anethole, m-methoxybenzaldehyde, and 3-HBA as the major constituents. Molecular docking attributed the antibiofilm activity to an active ligand present in 3-HBA, which strongly interacted with the active site residues of AgrA and SarA of S. aureus. At a subinhibitory concentration of 2.4 mg/mL, the extract showed biofilm inhibition. Similarly, 3-HBA inhibited biofilm activity at 25 μg/mL (90.34%), 12.5 μg/mL (77.21%), and 6.25 μg/mL (62.69%) concentrations. Marked attrition in bacterial spreading was observed at 2.4 mg/mL (crude extract) and 25 μg/mL (3-HBA) concentrations. The methanol extract of I. verum and 3-HBA markedly inhibited β-hemolytic and proteolytic activities of S. aureus. At the lowest concentration, the I. verum extract (2.4 mg/mL) and 3-HBA (25 μg/mL) did not inhibit bacterial growth. Optical microscopy and SEM analysis confirmed that I. verum and 3-HBA significantly reduced biofilm dispersion without disturbing bacterial growth. Together, we found that the antibiofilm activity of I. verum and 3-HBA strongly targeted the Agr and Sar systems of S. aureus.}, } @article {pmid35554762, year = {2022}, author = {Saptami, K and Arokia Balaya Rex, D and Chandrasekaran, J and Rekha, PD}, title = {Competitive interaction of thymol with cviR inhibits quorum sensing and associated biofilm formation in Chromobacterium violaceum.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {3}, pages = {629-638}, pmid = {35554762}, issn = {1618-1905}, support = {2019-5152/CMB/BMS//Indian Council of Medical Research/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; Chromobacterium ; Gram-Negative Bacteria ; Plant Extracts/chemistry ; *Quorum Sensing ; *Thymol/pharmacology ; }, abstract = {Biofilm formation associated with quorum sensing (QS) is a community behaviour displayed by many gram-negative pathogenic bacteria that provide survival advantages in hostile conditions. The inhibitors of QS interrupt bacterial communication and coordinated cell signalling for community aggregation in the biofilm. Thymol, a natural monoterpenoid, was tested against QS in Chromobacterium violaceum. As the first step, the interaction of thymol with cviR protein was investigated using in silico approach followed by validation using detailed in vitro experiments. The QS and biofilm studies were performed using the wild type of strain C. violaceum ATCC 12,472 and a mini-Tn5 mutant CV026. The MIC of thymol was established by the broth micro-dilution method, and IC50 value for violacein inhibition was quantified spectrophotometrically by extracting the violacein from the treated cells. Inhibitory effect of thymol on the biofilm was quantified by the crystal violet staining method, and scanning electron microscopy (SEM) was employed for biofilm visualization. The expression of biofilm associated genes (hmsH, hmsR, pilB, and pilT) was evaluated by qRT-PCR analysis. The in silico molecular interactions of thymol with cviR exhibited a G-score of - 5.847 kcal/mol, binding with TYR-80 and SER-155 by Pi-Pi stacking and H-bond, respectively. The MIC of thymol was 160 µg/mL, and the IC50 for violacein inhibition was estimated to be 28 µg/mL. The thymol treatment significantly reduced the biofilm viability and biomass by > 80% along with disruption of the well-organized biofilm architecture. QS inhibitory activity of thymol resulted in the reduction of exopolysaccharide production, swarming motility, and downregulation of biofilm-associated hmsH, hmsR, pilB, and pilT genes. This data establishes the QS inhibitory role of thymol in the biofilm formation in C. violaceum.}, } @article {pmid35550403, year = {2022}, author = {Song, Y and Wang, Z and Long, Y and Mao, Y and Jiang, F and Lu, Y}, title = {2-Alkyl-anthraquinones inhibit Candida albicans biofilm via inhibiting the formation of matrix and hyphae.}, journal = {Research in microbiology}, volume = {173}, number = {6-7}, pages = {103955}, doi = {10.1016/j.resmic.2022.103955}, pmid = {35550403}, issn = {1769-7123}, mesh = {Anthraquinones/pharmacology ; Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans/genetics ; Gene Expression Profiling ; *Hyphae/genetics ; }, abstract = {Candida albicans can form biofilm on biotic and abiotic surfaces of medical implants to cause superficial and systemic infections under specific condition. The formation of hyphae and matrix of C. albicans are considered as probable virulence factors. We assessed the inhibitory activities of 26 anthraquinones against C. albicans biofilm formation, which were substituted by different functional groups including hydroxyl groups, amino groups, carboxyl groups, alkyl groups, and glycoside groups at C1- or C2-position. Among them, anthraquinones without substituents at other positions but only an alkyl group attached to C2-position, namely 2-alkyl-anthraquinones were determined to have significant anti-biofilm activities. Furthermore, 2-ethylanthraquinone can significantly affect genes related to extracellular matrix (PMT6 and IFD6), and hyphal formation (HWP1, ECE1 and EFG1), leading to the disrupted formation of biofilm, by detail transcriptomics analysis. We believed that 2-ethylanthraquinone could inspire more discoveries of anti-biofilm agents against C. albicans.}, } @article {pmid35549350, year = {2022}, author = {Giedraitiene, A and Pereckaite, L and Bredelyte-Gruodiene, E and Virgailis, M and Ciapiene, I and Tatarunas, V}, title = {CTX-M-producing Escherichia coli strains: resistance to temocillin, fosfomycin, nitrofurantoin and biofilm formation.}, journal = {Future microbiology}, volume = {17}, number = {}, pages = {789-802}, doi = {10.2217/fmb-2021-0202}, pmid = {35549350}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli/genetics ; *Escherichia coli Infections/microbiology ; *Fosfomycin/pharmacology ; Humans ; Microbial Sensitivity Tests ; Nitrofurantoin/pharmacology ; Penicillins ; beta-Lactamases/genetics ; }, abstract = {Aim: ESBL-producing and bacterial biofilms-forming Escherichia coli are associated with antimicrobial treatment failure. This study aimed to investigate the phenotypic resistance mechanisms of CTX-M E. coli against old antibiotics - cell wall synthesis inhibitors temocillin, nitrofurantoin and fosfomycin. Materials & Methods: Susceptibility to old antibiotics testing was performed using disk diffusion method, biofilm formation was evaluated spectrophotometrically, and PCR was used for the determination of CTX-M type. Results & conclusion: Temocillin was active against nearly 93%, nitrofurantoin and fosfomycin, respectively, 91.7% and 98.6% of tested E. coli. Thus, it demonstrated to be a good alternative therapeutic option against ESBL infections. Bacteria resistant to old antibiotics had CTX-M-15 or CTX-M-15, TEM-1 and OXA-1 combinations. No significant association was found between CTX-M E. coli resistance to temocillin, nitrofurantoin and fosfomycin; however, the level of biofilm formation was found as not affected by the type of CTX-M β-lactamases.}, } @article {pmid35547150, year = {2022}, author = {Yang, R and Lai, B and Liao, K and Liu, B and Huang, L and Li, S and Gu, J and Lin, Z and Chen, Y and Wang, S and Qiu, Y and Deng, J and Chen, S and Zhuo, C and Zhou, Y}, title = {Overexpression of BIT33_RS14560 Enhances the Biofilm Formation and Virulence of Acinetobacter baumannii.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {867770}, pmid = {35547150}, issn = {1664-302X}, abstract = {Acinetobacter baumannii, a strictly aerobic, non-lactose fermented Gram-negative bacteria, is one of the important pathogens of nosocomial infection. Major facilitator superfamily (MFS) transporter membrane proteins are a class of proteins that widely exists in microbial genomes and have been revealed to be related to biofilm formation in a variety of microorganisms. However, as one of the MFS transporter membrane proteins, little is known about the role of BIT33_RS14560 in A. baumannii. To explore the effects of BIT33_RS14560 on biofilm formation of A. baumannii, the biofilm formation abilities of 62 isolates were firstly investigated and compared with their transcript levels of BIT33_RS14560. Then, this specific gene was over-expressed in a standard A. baumannii strain (ATCC 19606) and two isolates of extensively drug-resistant A. baumannii (XDR-Ab). Bacterial virulence was observed using a Galleria mellonella infection model. High-throughput transcriptome sequencing (RNA seq) was performed on ATCC 19606 over-expressed strain and its corresponding empty plasmid control strain. Spearman's correlation analysis indicated a significant negative correlation (R = -0.569, p = 0.000) between the △CT levels of BIT33_RS1456 and biofilm grading of A. baumannii isolates. The amount of A. baumannii biofilm was relatively high within 12-48 h. Regardless of standard or clinical strains; the biofilm biomass in the BIT33_RS14560 overexpression group was significantly higher than that in the control group (p < 0.0001). Kaplan-Meier survival curve analysis showed that the mortality of G. mellonella was significantly higher when infected with the BIT33_RS14560 overexpression strain (χ[2] = 8.462, p = 0.004). RNA-Seq showed that the mRNA expression levels of three genes annotated as OprD family outer membrane porin, glycosyltransferase family 39 protein, and glycosyltransferase family 2 protein, which were related to bacterial adhesion, biofilm formation, and virulence, were significantly upregulated when BIT33_RS14560 was over-expressed. Our findings provided new insights in identifying potential drug targets for the inhibition of biofilm formation. We also developed a practical method to construct an over-expressed vector that can stably replicate in XDR-Ab isolates.}, } @article {pmid35546969, year = {2021}, author = {Mohammadi Mollaahmadi, C and Anzabi, Y and Shayegh, J}, title = {Comparison of the Frequency of Biofilm-Forming Genes (icaABCD) in Methicillin-Resistant S. aureus Strains Isolated from Human and Livestock.}, journal = {Archives of Razi Institute}, volume = {76}, number = {6}, pages = {1655-1663}, pmid = {35546969}, issn = {2008-9872}, mesh = {Animals ; Humans ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Livestock ; Methicillin Resistance ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Rifampin ; Staphylococcus aureus ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) can cause infections in both human and animal groups, which is a serious threat to public health worldwide. Attachment and colonization are the first steps for S. aureus pathogenesis, and biofilm-mediated infections have a significant negative impact on human and animal health. The MRSA can adapt to different environments and give rise to different strains of human and animal MRSA, causing transmissions of the disease between humans and animals. This study aimed to investigate biofilm production in vitro, and the presence of icaABCD genes in MRSA isolates in both human as well as the disease transmission between human and animal strains. In total, 39 human and 35 livestock isolates were evaluated by the Congo Red Agar method. The presence of mecA and icaABCDR genes were assessed by polymerase chain reaction (PCR), and finally, the PCR products were examined by agarose gel electrophoresis. The results showed that the mecA gene frequency in human and animal isolates was 64.1% and 36.1%, respectively, and there was a significant relationship between mecA and icaAD in human isolates. In addition, significant relationships were found between icaA and Rifampicin and also between icaC and Chloramphenicol and Penicillin in human isolates. In animal isolates, there was a significant relationship between mecA and Trimethoprim as well as between icaR and Rifampicin. It was concluded that all operon ica genes were involved in biofilm production, but icaA and icaD genes in MRSA were more closely associated with mecA. Both animal and human strains can be involved in disease transmission, but this conclusion should be made cautiously.}, } @article {pmid35546788, year = {2022}, author = {Yılmaz Öztürk, B and Yenice Gürsu, B and Dağ, İ}, title = {In vitro effect of farnesol on planktonic cells and dual biofilm formed by Candida albicans and Escherichia coli.}, journal = {Biofouling}, volume = {38}, number = {4}, pages = {355-366}, doi = {10.1080/08927014.2022.2066530}, pmid = {35546788}, issn = {1029-2454}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; Escherichia coli ; *Farnesol/pharmacology ; Microbial Sensitivity Tests ; Plankton ; }, abstract = {Many biofilm studies have focused on axial biofilms, however biofilms in nature and in vivo environment are multi-species. Farnesol is a sesquiterpene alcohol found in many essential oils. This study investigated the in vitro effects of farnesol on planktonic cells and biofilms of Candida albicans and Escherichia coli. The ultrastructural morphology of farnesol treated cells was evaluated by TEM. According to the XTT results, farnesol caused a significant decrease in metabolic activity and scanning electron microscope images confirmed a reduction in the preformed biofilm as a result of farnesol treatment for single species C. albicans and E. coli biofilms. Although farnesol has less effect on dual species biofilm compared to the single species biofilms, its effect on the dual biofilm was found to be stronger than amphotericin B or ampicillin. Further studies are needed to clarify the role of farnesol on fungal-bacterial biofilms.}, } @article {pmid35543448, year = {2022}, author = {Vidal, JM and Ruiz, P and Carrasco, C and Barros, J and Sepúlveda, D and Ruiz-Tagle, N and Romero, A and Urrutia, H and Oliver, C}, title = {Piscirickettsia salmonis forms a biofilm on nylon surface using a CDC Biofilm Reactor.}, journal = {Journal of fish diseases}, volume = {45}, number = {8}, pages = {1099-1107}, doi = {10.1111/jfd.13632}, pmid = {35543448}, issn = {1365-2761}, support = {//Agencia Nacional de Investigación y Desarrollo (ANID)/ ; 11180994//The Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)/ ; 15110027//Fondo de Financiamiento de Centros de Investigación (FONDAP) Interdisciplinary Center for Aquaculture Research (INCAR)/ ; //Vicerrectoría de Investigación, Desarrollo y Creación Artística of the Universidad Austral de Chile (VIDCA-UACh)/ ; }, mesh = {Animals ; Biofilms ; Centers for Disease Control and Prevention, U.S. ; *Fish Diseases/microbiology ; Nylons ; *Piscirickettsia ; *Piscirickettsiaceae Infections/microbiology ; Polyethylene ; Stainless Steel ; United States ; }, abstract = {Research into Piscirickettsia salmonis biofilms on materials commonly used in salmon farming is crucial for understanding its persistence and virulence. We used the CDC Biofilm Reactor to investigate P. salmonis (LF-89 and EM-90) biofilm formation on Nylon, Stainless steel (316L), Polycarbonate and High-Density Polyethylene (HDPE) surfaces. After 144 h of biofilm visualization by scanning confocal laser microscopy under batch growth conditions, Nylon coupons generated the greatest biofilm formation and coverage compared to Stainless steel (316L), Polycarbonate and HDPE. Additionally, P. salmonis biofilm formation on Nylon was significantly greater (p ≤ .01) than Stainless steel (316L), Polycarbonate and HDPE at 288 h. We used Nylon coupons to determine the kinetic parameters of the planktonic and biofilm phases of P. salmonis. The two strains had similar latencies in the planktonic phase; however, LF-89 maximum growth was 2.5 orders of magnitude higher (Log cell ml[-1]). Additionally, LF-89 had a specified growth rate (µmax) of 0.0177 ± 0.006 h[-1] and a generation time of 39.2 h. This study contributes to a deeper understanding of the biofilm formation by P. salmonis and elucidates the impact of the biofilm on aquaculture systems.}, } @article {pmid35538403, year = {2022}, author = {Pourhajibagher, M and Alaeddini, M and Etemad-Moghadam, S and Rahimi Esboei, B and Bahrami, R and Miri Mousavi, RS and Bahador, A}, title = {Quorum quenching of Streptococcus mutans via the nano-quercetin-based antimicrobial photodynamic therapy as a potential target for cariogenic biofilm.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {125}, pmid = {35538403}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; *Photochemotherapy/methods ; Quercetin/pharmacology ; Quorum Sensing ; Reactive Oxygen Species/pharmacology ; Streptococcus mutans ; }, abstract = {BACKGROUND: Quorum sensing (QS) system can regulate the expression of virulence factors and biofilm formation in Streptococcus mutans. Antimicrobial photodynamic therapy (aPDT) inhibits quorum quenching (QQ), and can be used to prevent microbial biofilm. We thereby aimed to evaluate the anti-biofilm potency and anti-metabolic activity of nano-quercetin (N-QCT)-mediated aPDT against S. mutans. Also, in silico evaluation of the inhibitory effect of N-QCT on the competence-stimulating peptide (CSP) of S. mutans was performed to elucidate the impact of aPDT on various QS-regulated genes.

METHODS: Cytotoxicity and intracellular reactive oxygen species (ROS) generation were assessed following synthesis and confirmation of N-QCT. Subsequently, the minimum biofilm inhibitory concentration (MBIC) of N-QCT against S. mutans and anti-biofilm effects of aPDT were assessed using colorimetric assay and plate counting. Molecular modeling and docking analysis were performed to confirm the connection of QCT to CSP. The metabolic activity of S. mutans and the expression level of various genes involved in QS were evaluated by flow cytometry and reverse transcription quantitative real-time PCR, respectively.

RESULTS: Successful synthesis of non-toxic N-QCT was confirmed through several characterization tests. The MBIC value of N-QCT against S. mutans was 128 μg/mL. Similar to the crystal violet staining, the results log10 CFU/mL showed a significant degradation of preformed biofilms in the group treated with aPDT compared to the control group (P < 0.05). Following aPDT, metabolic activity of S. mutans also decreased by 85.7% (1/2 × MBIC of N-QCT) and 77.3% (1/4 × MBIC of N-QCT), as compared to the control values (P < 0.05). In silico analysis showed that the QCT molecule was located in the site formed by polypeptide helices of CSP. The relative expression levels of the virulence genes were significantly decreased in the presence of N-QCT-mediated aPDT (P < 0.05).

CONCLUSIONS: The combination of N-QCT with blue laser as a QQ-strategy leads to maximum ROS generation, disrupts the microbial biofilm of S. mutans, reduces metabolic activity, and downregulates the expression of genes involved in the QS pathway by targeting genes of the QS signaling system of S. mutans.}, } @article {pmid35537700, year = {2022}, author = {He, Y and Pang, J and Yang, Z and Zheng, M and Yu, Y and Liu, Z and Zhao, B and Hu, G and Yin, R}, title = {Toluidine blue O-induced photoinactivation inhibit the biofilm formation of methicillin-resistant Staphylococcus aureus.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {39}, number = {}, pages = {102902}, doi = {10.1016/j.pdpdt.2022.102902}, pmid = {35537700}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Hemolysis ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Tolonium Chloride/pharmacology ; }, abstract = {BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to conventional antimicrobial therapies, allowing for high morbidity and mortality. Photodynamic antimicrobial chemotherapy (PACT) is one method that combines visible harmless light with the optimum wavelength with photosensitizers or dyes, producing singlet oxygen ([1]O2) and reactive oxygen strains (ROS), making permanent damages to the target cells. The purpose of this research is to evaluate the suppression efficacy of toluidine blue O (TBO)-mediated PACT on mature MRSA biofilm in vitro.

METHODS: In this study, the 48 h mature biofilm of the multidrug-resistant Staphylococcus aureus strain MRSA252 was used. The photodynamic therapy (PDT) group was treated with different concentrations of TBO (0.5, 0.75, 1.0 or 1.25 µM) and different doses of red light (635 ± 5 nm wavelength; 30 or 50 J/cm[2]). The biofilms viability after PDT were evaluated by crystal violet (CV) staining assay and {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetra-zolium hydroxide} (XTT) assay; meanwhile, the morphological changes were detected by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), separately. Moreover, the biofilms virulence was evaluated by red blood cell (RBC) hemolysis assay and staphylococcal virulence factor enterotoxins A (SEA) detected by enzyme linked immunosorbent assay (ELISA). After PDT, the biofilm was re-cultured for extra 48 h. Its formation viability and virulence were detected again. All data were analyzed by ANOVAs followed by the Games Howell post hoc test (α = 0.05).

RESULTS: The biofilm was inactivated about 2.3 log10 at 1.25 µM with 30 J/cm[2] illumination, and 3.5 log10 with 50 J/cm[2] after PDT (P<0.05). XTT assays demonstrated the viability of mature MRSA biofilms was reduced after PACT. PDT group shows a distinct reduction in RBC hemolysis rate and the concentration of SEA compared to the control groups. The morphological features of the biofilms showed great changes, such as shrinkage, fissure, fragmentation, and rarefaction after being treated by TBO-PDT and observed by SEM. The recovery of the structure and virulence of biofilm were suppressed after PDT.

CONCLUSION: TBO-mediated PDT could destroy the biofilm structure, reduce its virulence and depress its self-recovery.}, } @article {pmid35537631, year = {2022}, author = {Jiang, M and Zhang, Y and Zheng, J and Li, H and Ma, J and Zhang, X and Wei, Q and Wang, X and Zhang, X and Wang, Z}, title = {Mechanistic insights into CO2 pressure regulating microbial competition in a hydrogen-based membrane biofilm reactor for denitrification.}, journal = {Chemosphere}, volume = {303}, number = {Pt 1}, pages = {134875}, doi = {10.1016/j.chemosphere.2022.134875}, pmid = {35537631}, issn = {1879-1298}, mesh = {Bacteria ; Biofilms ; Bioreactors/microbiology ; Carbon ; Carbon Dioxide ; *Denitrification ; *Hydrogen/chemistry ; }, abstract = {CO2 is a proven pH regulator in hydrogen-based membrane biofilm reactor (H2-MBfR) but how its pressure regulates microbial competition in this system remains unclear. This work evaluates the CO2 pressure dependent system performance, CO2 allocation, microbial structure and activity of CO2 source H2-MBfR. The optimum system performance was reached at the CO2 pressure of 0.008 MPa, and this pressure enabled 0.18 g C/(m[2]·d) of dissolved inorganic carbon (DIC) allocated to denitrifying bacteria (DNB) for carbon source anabolism and denitrification-related proton compensation, while inducing a bulk liquid pH (pH 7.4) in favor of DNB activity by remaining 0.21 g C/(m[2]·d) of DIC as pH buffer. Increasing CO2 pressure from 0.008 to 0.016 MPa caused the markedly changed DNB composition, and the diminished DNB population was accompanied by the enrichment of sulfate-reducing bacteria (SRB). A high CO2 pressure of 0.016 MPa was estimated to induce the enhanced SRB activity and weakened DNB activity.}, } @article {pmid35536751, year = {2022}, author = {Yang, M and Özdemir, Z and Kim, H and Nah, S and Andris, E and Li, X and Wimmer, Z and Yoon, J}, title = {Acid-Responsive Nanoporphyrin Evolution for Near-Infrared Fluorescence-Guided Photo-Ablation of Biofilm.}, journal = {Advanced healthcare materials}, volume = {11}, number = {14}, pages = {e2200529}, doi = {10.1002/adhm.202200529}, pmid = {35536751}, issn = {2192-2659}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Phototherapy/methods ; *Porphyrins/pharmacology ; }, abstract = {Combating biofilm infections remains a challenge due to the shield and acidic conditions. Herein, an acid-responsive nanoporphyrin (PN3-NP) based on the self-assembly of a water-soluble porphyrin derivative (PN3) is constructed. Additional kinetic control sites formed by the conjugation of the spermine molecules to a porphyrin macrocycle make PN3 self-assemble into stable nanoparticles (PN3-NP) in the physiological environment. Noteworthily, near-infrared (NIR) fluorescence monitoring and synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) effects of PN3-NP can be triggered by the acidity in biofilms, accompanied by intelligent transformation into dot-like nanospheres. Thus, damage to normal tissue is effectively avoided and accurate diagnosis and treatment of biofilms is achieved successfully. The good results of fluorescence imaging-guided photo-ablation of antibiotic-resistant strains methicillin-resistant Staphylococcus aureus (MRSA) biofilms verify that PN3-NP is a promising alternative to antibiotics. Meanwhile, this strategy also opens new horizons to engineer smart nano-photosensitizer for accurate diagnosis and treatment of biofilms.}, } @article {pmid35535650, year = {2022}, author = {Savorana, G and Słomka, J and Stocker, R and Rusconi, R and Secchi, E}, title = {A microfluidic platform for characterizing the structure and rheology of biofilm streamers.}, journal = {Soft matter}, volume = {18}, number = {20}, pages = {3878-3890}, pmid = {35535650}, issn = {1744-6848}, mesh = {Bacteria ; *Biofilms ; Hydrodynamics ; *Microfluidics ; Reproducibility of Results ; Rheology ; }, abstract = {Biofilm formation is the most successful survival strategy for bacterial communities. In the biofilm lifestyle, bacteria embed themselves in a self-secreted matrix of extracellular polymeric substances (EPS), which acts as a shield against mechanical and chemical insults. When ambient flow is present, this viscoelastic scaffold can take a streamlined shape, forming biofilm filaments suspended in flow, called streamers. Streamers significantly disrupt the fluid flow by causing rapid clogging and affect transport in aquatic environments. Despite their relevance, the structural and rheological characterization of biofilm streamers is still at an early stage. In this work, we present a microfluidic platform that allows the reproducible growth of biofilm streamers in controlled physico-chemical conditions and the characterization of their biochemical composition, morphology, and rheology in situ. We employed isolated micropillars as nucleation sites for the growth of single biofilm streamers under the continuous flow of a diluted bacterial suspension. By combining fluorescent staining of the EPS components and epifluorescence microscopy, we were able to characterize the biochemical composition and morphology of the streamers. Additionally, we optimized a protocol to perform hydrodynamic stress tests in situ, by inducing controlled variations of the fluid shear stress exerted on the streamers by the flow. Thus, the reproducibility of the formation process and the testing protocol make it possible to perform several consistent experimental replicates that provide statistically significant information. By allowing the systematic investigation of the role of biochemical composition on the structure and rheology of streamers, this platform will advance our understanding of biofilm formation.}, } @article {pmid35534609, year = {2022}, author = {Momenijavid, M and Salimizand, H and Korani, A and Dianat, O and Nouri, B and Ramazanzadeh, R and Ahmadi, A and Rostamipour, J and Khosravi, MR}, title = {Effect of calcium hydroxide on morphology and physicochemical properties of Enterococcus faecalis biofilm.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {7595}, pmid = {35534609}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Calcium Hydroxide/pharmacology ; *Enterococcus faecalis ; Root Canal Irrigants/pharmacology ; Root Canal Therapy ; }, abstract = {Calcium hydroxide Ca(OH)2 has been used as an intracanal medicament to targets microbial biofilms and avert secondary infection in the root canal system. This study evaluated the effects of this material on the morphology and physicochemical properties of an established in-vitro biofilm of Enterococcus faecalis. A biofilm of E. faecalis was grown in multichannel plates. The chemicals including Ca[2+], OH[-], and saturated Ca(OH)2 (ie 21.6 mM) were prepared in order to evaluate which component eradicated or amplified biofilm structure. Various biochemical and microscopic methods were used to investigate the properties of the biofilm. Biofilms treated with Ca(OH)2 absorbed more Ca[2+] because of the alkaline pH of the environment and the ions affected the physicochemical properties of the E. faecalis biofilm. A denser biofilm with more cavities and a granular surface was observed in the presence of Ca[2+] ions. This resulted in a decrease in the surface-to-biofilm ratio with increases in its biomass, thickness, colony size, and volume. Calcium hydroxide did not destroy E. faecalis biofilms but rather contributed to the biofilm structure. This in-vitro study sheds light on a missing link in the formation of E. faecalis biofilm in which the Ca[2+] in Ca(OH)2.}, } @article {pmid35532279, year = {2022}, author = {Doucet, AN and Slipski, CJ and Golding, GR and Mulvey, MR and Bay, DC}, title = {Generation of Greater Bacterial Biofilm Biomass using PCR-Plate Deep Well Microplate Devices.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {182}, pages = {}, doi = {10.3791/63069}, pmid = {35532279}, issn = {1940-087X}, mesh = {Anti-Bacterial Agents ; Bacteria ; Biofilms ; Biomass ; *Escherichia coli ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Polypropylenes ; *Polystyrenes ; Pseudomonas aeruginosa ; }, abstract = {Bacterial biofilms are difficult to eradicate from surfaces using conventional antimicrobial interventions. High-throughput 96-well microplate methods are frequently used to cultivate bacterial biofilms for rapid antimicrobial susceptibility testing to calculate minimal biofilm eradication concentration (MBEC) values. Standard biofilm devices consist of polystyrene pegged-lids fitted to 96-well microplates and are ideal for measuring biofilm biomass and MBEC values, but these devices are limited by available peg surface area for biomass accumulation and cost. Here, we outline a protocol to use self-assembled polypropylene 96-well deep well PCR-plate pegged-lid device to grow Escherichia coli BW25113 and Pseudomonas aeruginosa PAO1 biofilms. A comparison of 24-hour biofilms formed on standard and deep well devices by each species using crystal violet biomass staining and MBEC determination assays are described. The larger surface area of deep well devices expectedly increased overall biofilm formation by both species 2-4-fold. P. aeruginosa formed significantly greater biomass/mm[2] on deep well pegs as compared to the standard device. E. coli had greater biomass/mm[2] on standard polystyrene devices as compared the deep well device. Biofilm eradication assays with disinfectants such as sodium hypochlorite (bleach) or benzalkonium chloride (BZK) showed that both compounds could eliminate E. coli and P. aeruginosa biofilms from both devices but at different MBEC values. BZK biofilm eradication resulted in variable E. coli MBEC values between devices, however, bleach demonstrated reproducible MBEC values for both species and devices. This study provides a high throughput deep well method for growing larger quantities of biofilms on polypropylene devices for downstream studies requiring higher amounts of static biofilm.}, } @article {pmid35532264, year = {2022}, author = {Buckingham-Meyer, K and Miller, LA and Parker, AE and Walker, DK and Sturman, P and Novak, I and Goeres, DM}, title = {Harvesting and Disaggregation: An Overlooked Step in Biofilm Methods Research.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {182}, pages = {}, doi = {10.3791/62390}, pmid = {35532264}, issn = {1940-087X}, mesh = {*Biofilms ; *Sonication ; }, abstract = {Biofilm methods consist of four distinct steps: growing the biofilm in a relevant model, treating the mature biofilm, harvesting the biofilm from the surface and disaggregating the clumps, and analyzing the sample. Of the four steps, harvesting and disaggregation are the least studied but nonetheless critical when considering the potential for test bias. This article demonstrates commonly used harvesting and disaggregation techniques for biofilm grown on three different surfaces. The three biofilm harvesting and disaggregation techniques, gleaned from an extensive literature review, include vortexing and sonication, scraping and homogenization, and scraping, vortexing and sonication. Two surface types are considered: hard non-porous (polycarbonate and borosilicate glass) and porous (silicone). Additionally, we provide recommendations for the minimum information that should be included when reporting the harvesting technique followed and an accompanying method to check for bias.}, } @article {pmid35531251, year = {2022}, author = {Mekky, AF and Hassanein, WA and Reda, FM and Elsayed, HM}, title = {Anti-biofilm potential of Lactobacillus plantarum Y3 culture and its cell-free supernatant against multidrug-resistant uropathogen Escherichia coli U12.}, journal = {Saudi journal of biological sciences}, volume = {29}, number = {4}, pages = {2989-2997}, pmid = {35531251}, issn = {1319-562X}, abstract = {Uropathogens develop biofilms on urinary catheters, resulting in persistent and chronic infections that are associated with resistance to antimicrobial therapy. Therefore, the current study was performed to control biofilm-associated urinary tract infections through assaying the anti-biofilm ability of lactic acid bacteria (LAB) against multidrug-resistant (MDR) uropathogens. Twenty LAB were obtained from pickles and fermented dairy products, and screened for their anti-biofilm and antimicrobial effects against MDR Escherichia coli U12 (ECU12). Lactobacillus plantarum Y3 (LPY3) (MT498405), showed the highest inhibitory effect and biofilm production. Pre-coating of a microtitre plate with LPY3 culture was more potent than co-incubation. Pre-coating with LPY3 culture generated a higher anti-biofilm effect with an adherence of 14.5% than cell free supernatant (CFS) (31.2%). Anti-biofilm effect of CFS was heat stable up to 100 °C with higher effect at pH 4-6. Pre-coating urinary catheter with LPY3 culture reduced the CFU/cm[2] of ECU12 attached to the catheter for up to seven days. Meanwhile, CFS reduced the ECU12 CFU/cm[2] for up to four days. Scanning electron microscope confirmed the reduction of ECU12 adherence to catheters after treatment with CFS. Therefore, Lactobacillus plantarum can be applied in medical devices as prophylactic agent and as a natural biointervention to treat urinary tract infections.}, } @article {pmid35527134, year = {2022}, author = {Joshi, KM and Shelar, A and Kasabe, U and Nikam, LK and Pawar, RA and Sangshetti, J and Kale, BB and Singh, AV and Patil, R and Chaskar, MG}, title = {Biofilm inhibition in Candida albicans with biogenic hierarchical zinc-oxide nanoparticles.}, journal = {Biomaterials advances}, volume = {134}, number = {}, pages = {112592}, doi = {10.1016/j.msec.2021.112592}, pmid = {35527134}, issn = {2772-9508}, mesh = {Animals ; *Biofilms/drug effects ; *Candida albicans/metabolism ; Lignin ; Mice ; *Nanoparticles/chemistry ; Rats ; *Zinc Oxide/pharmacology ; }, abstract = {The present study demonstrates lignin (L), fragments of lignin (FL), and oxidized fragmented lignin (OFL) as templates for the synthesis of zinc oxide nanoparticles (ZnO NPs) viz., lignin-ZnO (L-ZnO), hierarchical FL-ZnO, and OFL-ZnO NPs. The X-ray diffraction patterns confirmed the formation of phase pure ZnO NPs with a hexagonal wurtzite structure. Electron microscopy confirmed the hierarchical structures with one-dimensional arrays of ZnO NPs with an average particle diameter of 40 nm. The as-synthesized L-ZnO, FL-ZnO, and OFL-ZnO NPs were tested in-vitro for growth and virulence inhibition (morphogenesis and biofilm) in Candida albicans. L-ZnO, FL-ZnO, and OFL-ZnO NPs all inhibited growth and virulence. Growth and virulence inhibitions were highest (more than 90%, respectively at 125, 31.2, and 62.5 μg/mL) in presence of FL-ZnO NPs, indicating that the hierarchical FL-ZnO NPs were potent growth and virulence inhibiting agent than non-hierarchical ZnO NPs. Furthermore, the real-time polymerase chain (RT-PCR) was used to study the virulence inhibition molecular mechanisms of L-ZnO, FL-ZnO, and OFL-ZnO NPs. RT-PCR results showed that the downregulation of phr1, phr2, efg1, hwp1, ras1, als3 and als4, and the upregulation of bcy1, nrg1, and tup1 genes inhibited the virulence in C. albicans. Lastly, we also performed in-vitro test cell cytotoxicity on the cell line, mouse embryo 3T3L1, and in-vivo toxicity on Rats, which showed that FL-ZnO NPs were biocompatible and nontoxic.}, } @article {pmid35526753, year = {2022}, author = {Choi, JH and Jung, EH and Lee, ES and Jung, HI and Kim, BI}, title = {Anti-biofilm activity of chlorhexidine-releasing elastomerics against dental microcosm biofilms.}, journal = {Journal of dentistry}, volume = {122}, number = {}, pages = {104153}, doi = {10.1016/j.jdent.2022.104153}, pmid = {35526753}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cattle ; *Chlorhexidine/pharmacology ; Dental Enamel ; Humans ; Saliva/microbiology ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVE: To evaluate the anti-biofilm activity of chlorhexidine-releasing elastomerics (CRE) developed to prevent biofilm-related diseases in orthodontic patients, using dental microcosm biofilms.

METHODS: Elastomerics coated with one of two solutions (CRE 1 and 2) were attached to bovine enamel specimens. Uncoated elastomerics were used for negative (distilled water [DW]) and positive (0.1% chlorhexidine [CHX]) control groups. After saliva inoculation on the surface of the specimen for biofilm formation, DW and CRE groups were treated with DW, and the positive control group was treated with CHX twice a day for 5 min. After 7 days of biofilm formation, colony-forming units (CFUs, total and aciduric bacteria), red/green (R/G) ratio, biofilm thickness, live/dead cell ratio, and bacterial morphology in the biofilms were evaluated. Enamel demineralization was evaluated by fluorescence loss (ΔF).

RESULTS: The CFUs of total and aciduric bacteria and R/G ratios in the CRE groups were significantly lower than those in the DW group with a reduction by 13%, 13%, and 19%, respectively (p < 0.05). The CFUs of total bacteria was significantly lower in the CRE groups than in the 0.1% CHX group (p < 0.05). Among the CRE groups, only CRE 1 exhibited a significantly reduced biofilm thickness of 54% compared to the DW group (p < 0.05) and apparent changes in bacterial morphology. ΔF in the CRE groups was significantly higher by 36% compared to that in the DW group (p < 0.05).

CONCLUSIONS: CREs exhibited anti-biofilm and demineralization-inhibiting effect. Particularly, CRE 1 using dichloromethane as the solvent was most effective against biofilms.

CLINICAL SIGNIFICANCE: Chlorhexidine-releasing elastomerics exhibited increased anti-biofilm and demineralization-inhibiting effect compared to 0.1% chlorhexidine mouthwash. Therefore, it is possible to prevent biofilm-related diseases simply and effectively by applying chlorhexidine-releasing elastomerics to orthodontic patients.}, } @article {pmid35526677, year = {2022}, author = {Ball, AL and Augenstein, ED and Wienclaw, TM and Richmond, BC and Freestone, CA and Lewis, JM and Thompson, JS and Pickett, BE and Berges, BK}, title = {Characterization of Staphylococcus aureus biofilms via crystal violet binding and biochemical composition assays of isolates from hospitals, raw meat, and biofilm-associated gene mutants.}, journal = {Microbial pathogenesis}, volume = {167}, number = {}, pages = {105554}, doi = {10.1016/j.micpath.2022.105554}, pmid = {35526677}, issn = {1096-1208}, mesh = {Biofilms ; Deoxyribonucleases/pharmacology ; Endopeptidase K/pharmacology ; Gentian Violet ; Hospitals ; Humans ; Meat ; Phenols/pharmacology ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {Staphylococcus aureus (SA) is a gram-positive coccus and an opportunistic pathogen of humans. The ability of SA to form biofilms is an important virulence mechanism because biofilms are protected from host immune responses and antibiotic treatment. This study examines the relative biofilm strength of a variety of hospital and meat-associated strains of SA, using a crystal violet (CV) staining assay. Biofilms were treated with either DNase or proteinase K prior to CV staining, and compared to mock-treated results, to better understand the biochemical composition. Biofilm polysaccharide concentration was also measured using the phenol sulfuric-acid assay which was normalized to base biofilm strength. We found that hospital-associated isolates have biofilms that bind significantly more CV than for meat isolates and are significantly more protein and polysaccharide-based while meat isolates have significantly more DNA-based biofilms. This study also investigates the effects that biofilm-related genes have on biofilm formation and composition by analyzing specific transposon mutants of genes previously shown to play a role in biofilm development. agrA, atl, clfA, fnbA, purH, and sarA mutants produce significantly weaker biofilms (bind less CV) as compared to a wild-type control, whereas the acnA mutant produces a significantly stronger biofilm. Biofilms formed from these mutant strains were treated (or mock-treated) with DNase or proteinase K and tested with phenol and sulfuric acid to determine what role these genes play in biofilm composition. The acnA, clfA, fnbA, and purH mutants showed significant reduction in biofilm staining after either proteinase K or DNase treatment, agrA and sarA mutants showed significant biofilm reduction after only proteinase K treatment, and an atl mutant did not show significant biofilm reduction after either proteinase K or DNase treatment. These data suggest that biofilms that form without acnA, clfA, fnbA, and purH are DNA- and protein-based, that biofilms lacking agrA and sarA are mainly protein-based, and biofilms lacking atl are mainly polysaccharide-based. These results help to elucidate how these genes affect biofilm formation and demonstrate how mutating biofilm-related genes in SA can cause a change in biofilm composition.}, } @article {pmid35526143, year = {2023}, author = {Sorensen, HH and Magnussen, RA and DiBartola, AC and Mallory, NT and Litsky, AS and Stoodley, P and Swinehart, SD and Duerr, RA and Kaeding, CC and Flanigan, DC}, title = {Influence of Staphylococcus epidermidis biofilm on the mechanical strength of soft tissue allograft.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {41}, number = {2}, pages = {466-472}, pmid = {35526143}, issn = {1554-527X}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R01 GM124436/NH/NIH HHS/United States ; }, mesh = {Humans ; *Staphylococcus epidermidis ; *Tendons ; Biofilms ; Tensile Strength ; Biomechanical Phenomena ; Allografts ; Cadaver ; Stress, Mechanical ; }, abstract = {We sought to determine the impact of bacterial inoculation and length of exposure on the mechanical integrity of soft tissue tendon grafts. Cultures of Staphylococcus epidermidis were inoculated on human tibialis posterior cadaveric tendon to grow biofilms. A low inoculum in 10% growth medium was incubated for 30 min to replicate conditions of clinical infection. Growth conditions assessed included inoculum concentrations of 100, 1000, 10,000 colony-forming units (CFUs). Tests using the MTS Bionix system were performed to assess the influence of bacterial biofilms on tendon strength. Load-to-failure testing was performed on the tendons, and the ultimate tensile strength was obtained from the maximal force and the cross-sectional area. Displacements of tendon origin to maximal displacement were normalized to tendon length to obtain strain values. Tendon force-displacement and stress-strain relationships were calculated, and Young's modulus was determined. Elastic modulus and ultimate tensile strength decreased with increasing bioburden. Young's modulus was greater in uninoculated controls compared to tendons inoculated at 10,000 CFU (p = 0.0011) but unaffected by bacterial concentrations of 100 and 1000 CFU (p = 0.054, p = 0.078). Increasing bioburden was associated with decreased peak load to failure (p = 0.043) but was most significant compared to the control under the 10,000 and 1000 CFU growth conditions (p = 0.0005, p = 0.049). The presence of S. epidermidis increased elasticity and decreased ultimate tensile stress of human cadaveric tendons, with increasing effect noted with increasing bioburden.}, } @article {pmid35525944, year = {2022}, author = {Bakht, M and Alizadeh, SA and Rahimi, S and Kazemzadeh Anari, R and Rostamani, M and Javadi, A and Peymani, A and Marashi, SMA and Nikkhahi, F}, title = {Phenotype and genetic determination of resistance to common disinfectants among biofilm-producing and non-producing Pseudomonas aeruginosa strains from clinical specimens in Iran.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {124}, pmid = {35525944}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Disinfectants/pharmacology ; Edetic Acid/pharmacology ; Humans ; Iran ; Microbial Sensitivity Tests ; Phenotype ; *Pseudomonas aeruginosa ; Sodium Hypochlorite/pharmacology ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is a common pathogen in Hospitalized patients, and its various resistance mechanisms contribute to patient morbidity and mortality. The main aims of the present study were to assess the susceptibility of biofilm-producing and non-producing P. aeruginosa isolates to the five commonly used Hospital disinfectants, to evaluate the synergistic effect of selected disinfectants and Ethylene-diamine-tetra acetic acid (EDTA), and the effect of exposure to sub-inhibitory concentrations of Sodium hypochlorite on antimicrobial susceptibility test.

RESULTS: The results showed that sodium hypochlorite 5% and Ethanol 70% were the most and least effective disinfectants against P. aeruginosa, respectively. The addition of EDTA significantly increased the effectiveness of the selected disinfectants. The changes in the antibiotic-resistance profiles after exposure to sub-inhibitory concentrations of disinfectants were observed for different classes of antibiotics (Carbapenems, Aminoglycosides, Cephalosporins, Fluoroquinolones). As well as near the all isolates harbored efflux pump genes and 117 (97.5%) of isolates produced biofilm.

CONCLUSION: In the current study, the mixture of disinfectant and EDTA were the most suitable selection to disinfect Hospital surfaces and instruments. Also, it was clear that exposure to sub-inhibitory concentrations of Sodium hypochlorite results in resistance to some antibiotics in P. aeruginosa species. Strong and intermediate biofilm formers belonged to MDR/XDR strains. Future studies should include more complex microbial communities residing in the Hospitals, and more disinfectants use in Hospitals.}, } @article {pmid35525433, year = {2022}, author = {Yu, Y and Zhao, Y and He, Y and Pang, J and Yang, Z and Zheng, M and Yin, R}, title = {Inhibition of efflux pump encoding genes and biofilm formation by sub-lethal photodynamic therapy in methicillin susceptible and resistant Staphylococcus aureus.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {39}, number = {}, pages = {102900}, doi = {10.1016/j.pdpdt.2022.102900}, pmid = {35525433}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; Methicillin/pharmacology/therapeutic use ; *Methicillin-Resistant Staphylococcus aureus ; *Photochemotherapy/methods ; *Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus ; Tolonium Chloride ; }, abstract = {BACKGROUND: Photodynamic therapy (PDT) is an effective method to inactivate microorganisms which is based on reactive oxygen species (ROS) generated by photosensitizer and light at certain wavelength. Exposure to sub-lethal dose of PDT (sPDT) could activate the regulatory systems in the surviving bacteria in response to oxidative stress. This study aimed to evaluate the effect of sPDT on efflux pump and biofilm formation in Staphylococcus aureus (S. aureus), which are two important virulence related factors.

METHODS: Different light irradiation time and toluidine blue O (TBO) concentrations were tested to select a sPDT in methicillin-susceptible and methicillin-resistant S. aureus (MSSA and MRSA). Efflux function was evaluated with EtBr efflux experiment. Biofilm formation was evaluated by crystal violet staining. Gene expressions of norA, norB, sepA, mepA and mdeA following sPDT were analyzed with real-time PCR.

RESULTS: Sub-lethal PDT was set at 40 J/cm[2] associated with 0.5 μM TBO. Efflux function was significantly inhibited in both strains. The average expression levels of mdeA and mepA in MSSA and MRSA were increased by (3.09, 1.77, 1.57) and (3,44, 1.59, 6.29) fold change respectively, norB and sepA were decreased by (3.77, 6.14) and (3.02, 3.47) fold change respectively. Expression level of norA was decreased by 5.44-fold change in MSSA but increased by 2.80-fold change in MRSA. Biofilm formation in both strains was impeded.

CONCLUSIONS: TBO-mediated sPDT could inhibit efflux pump function, alter efflux pump encoding gene expression levels and retard biofilm formation in MSSA and MRSA. Therefore, sPDT is proposed as a potential adjuvant therapy for infections.}, } @article {pmid35525370, year = {2022}, author = {Chen, B and Zhou, S and Zhang, N and Liang, H and Sun, L and Zhao, X and Guo, J and Lu, H}, title = {Micro and nano bubbles promoted biofilm formation with strengthen of COD and TN removal synchronously in a blackened and odorous water.}, journal = {The Science of the total environment}, volume = {837}, number = {}, pages = {155578}, doi = {10.1016/j.scitotenv.2022.155578}, pmid = {35525370}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors/microbiology ; Denitrification ; Humans ; Nitrification ; Nitrogen ; Oxygen ; RNA, Ribosomal, 16S ; *Sewage ; Wastewater ; *Water ; }, abstract = {Blackening and odorization of rivers (BOR) distributed widely in urban cities with high density of human beings. Amounts of pollution control methods have been developed for treatment of these contaminated rivers. Among them, artificial aeration is an effective method for BOR treatment. As a novel developed aeration approach, Micro and nano bubbles (MNBs) takes advances of high specific surface area, high oxygen transfer, long retain time and interface effect. Thus, MNBs aeration was used in an anoxic-oxic (AO) process with traditional activated sludge methods to treat water of BOR in this study. A special designed reactor was made to allow both MNBs and macro bubbles aeration of which mode could be altered easily. The results revealed that MNBs improved removal of COD, NH4[+]-N and TN distinctly in water of BOR. MNBs provided high dissolved oxygen and promoted the transformation from floc sludge to biofilm. Significant difference between the microbial community of MNBs and macro bubbles sludges was revealed by 16S rRNA amplicon sequencing. Function predictions of MNBs and macro bubbles sludges indicated MNBs enhanced nitrification and aerobic ammonia oxidation without negative impact on denitrification. Moreover, biofilm formed bacteria were enriched by MNBs aeration. This study demonstrated MNBs would be a great potential for the combination of activated sludge and biofilm to treat BOR.}, } @article {pmid35525049, year = {2022}, author = {Zhai, S and Cheng, H and Wang, Q and Zhao, Y and Wang, A and Ji, M}, title = {Reinforcement of denitrification in a biofilm electrode reactor with immobilized polypyrrole/anthraquinone-2,6-disulfonate composite cathode.}, journal = {Journal of environmental management}, volume = {315}, number = {}, pages = {115203}, doi = {10.1016/j.jenvman.2022.115203}, pmid = {35525049}, issn = {1095-8630}, mesh = {Anthraquinones/chemistry ; Biofilms ; Bioreactors ; *Denitrification ; Electrodes ; *Graphite ; Hydrogen ; Nitrates ; Nitrogen ; Polymers/chemistry ; Pyrroles/chemistry ; }, abstract = {In biofilm electrode reactors (BER), good nitrate removal performance can be achieved through cooperation of heterotrophic and hydrogen autotrophic denitrification under low carbon/nitrogen conditions. In this study, we proposed a more multifunctional composite cathode, which combine immobilized anthraquinone-2,6-disulphonic disodium salt (AQDS) with polypyrrole (PPy) by electrochemical polymerization-doping method. The nitrate removal performance in BER with PPy/AQDS composite cathode was obviously improved, the nitrate removal rate (4.96 mg/L·h) was almost 2.0 times higher than the control BER system, and relatively stabled nitrate removal efficiency (≥90.0%) was also achieved even as the COD/N of 2.50. Compared with the bare graphite felt, PPy/AQDS coating cathode showed much better electrocatalytic activities, which was more advantageous for in situ production of H2 to support hydrogen autotrophic denitrification process. The PPy-bound AQDS could also act as electron intermediaries, which is beneficial to greatly promote indirect electron process between the denitrifiers and nitrate. Moreover, the PPy/AQDS composite layer formed many particles for improving the specific surface area and bio-attachment site for bacterial attachment, which was conducive for the proliferation of microorganisms and denitrification efficiency. The ratio of biofilm and electrode of PPy/AQDS biocathode was 0.32 ± 0.08, which was 2.46 times than bare electrode (0.13 ± 0.06). Furthermore, enrichment of specific denitrifiers and enhancement of denitrifying enzyme activity was obtained using PPy/AQDS treated electrode, the much higher relative abundance of Thauera of PPy/AQDS biocathode was 1.58 times to the application of bare graphite felt.}, } @article {pmid35524635, year = {2022}, author = {Gu, M and Jiang, S and Xu, X and Wu, MY and Chen, C and Yuan, Y and Chen, Q and Sun, Y and Chen, L and Shen, C and Guo, P and Liu, S and Zhao, E and Chen, S and Chen, S}, title = {Simultaneous Photodynamic Eradication of Tooth Biofilm and Tooth Whitening with an Aggregation-Induced Emission Luminogen.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {9}, number = {20}, pages = {e2106071}, pmid = {35524635}, issn = {2198-3844}, support = {22005050//National Natural Science Foundation of China/ ; 31925002//National Natural Science Foundation of China/ ; 2019YFA0904300//National Key Research and Development Program of China/ ; WHU2021-YXY00566//Wuhan University/ ; //Karolinska Institutet/ ; }, mesh = {Animals ; Biofilms ; *Dental Caries ; Extracellular Polymeric Substance Matrix ; Mammals ; Mice ; Streptococcus mutans/metabolism ; *Tooth Bleaching ; *Tooth Discoloration/drug therapy ; }, abstract = {Dental caries is among the most prevalent dental diseases globally, which arises from the formation of microbial biofilm on teeth. Besides, tooth whitening represents one of the fastest-growing areas of cosmetic dentistry. It will thus be great if tooth biofilm eradication can be combined with tooth whitening. Herein, a highly efficient photodynamic dental therapy strategy is reported for tooth biofilm eradication and tooth discoloration by employing a photosensitizer (DTTPB) with aggregation-induced emission characteristics. DTTPB can efficiently inactivate S. mutans, and inhibit biofilm formation by suppressing the expression of genes associated with extracellular polymeric substance synthesis, bacterial adhesion, and superoxide reduction. Its inhibition performance can be further enhanced through combined treatment with chlorhexidine. Besides, DTTPB exhibits an excellent tooth-discoloration effect on both colored saliva-coated hydroxyapatite and clinical teeth, with short treatment time (less than 1 h), better tooth-whitening performance than 30% hydrogen peroxide, and almost no damage to the teeth. DTTPB also demonstrates excellent biocompatibility with neglectable hemolysis effect on mouse red blood cells and almost no killing effect on mammalian cells, which enables its potential applications for simultaneous tooth biofilm eradication and tooth whitening in clinical dentistry.}, } @article {pmid35524324, year = {2022}, author = {Matthes, R and Jablonowski, L and Pitchika, V and Holtfreter, B and Eberhard, C and Seifert, L and Gerling, T and Vilardell Scholten, L and Schlüter, R and Kocher, T}, title = {Efficiency of biofilm removal by combination of water jet and cold plasma: an in-vitro study.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {157}, pmid = {35524324}, issn = {1472-6831}, mesh = {Biofilms ; *Dental Implants/microbiology ; Humans ; Microscopy, Electron, Scanning ; Pilot Projects ; *Plasma Gases/chemistry ; Surface Properties ; Titanium/chemistry ; Water ; }, abstract = {BACKGROUND: Peri-implantitis therapy is a major problem in implantology. Because of challenging rough implant surface and implant geometry, microorganisms can hide and survive in implant microstructures and impede debridement. We developed a new water jet (WJ) device and a new cold atmospheric pressure plasma (CAP) device to overcome these problems and investigated aspects of efficacy in vitro and safety with the aim to create the prerequisites for a clinical pilot study with these medical devices.

METHODS: We compared the efficiency of a single treatment with a WJ or curette and cotton swab (CC) without or with adjunctive use of CAP (WJ + CAP, CC + CAP) to remove biofilm in vitro from rough titanium discs. Treatment efficacy was evaluated by measuring turbidity up to 72 h for bacterial re-growth or spreading of osteoblast-like cells (MG-63) after 5 days with scanning electron microscopy. With respect to application safety, the WJ and CAP instruments were examined according to basic regulations for medical devices.

RESULTS: After 96 h of incubation all WJ and CC treated disks were turbid but 67% of WJ + CAP and 46% CC + CAP treated specimens were still clear. The increase in turbidity after WJ treatment was delayed by about 20 h compared to CC treatment. In combination with CAP the cell coverage significantly increased to 82% (WJ + CAP) or 72% (CC + CAP), compared to single treatment 11% (WJ) or 10% (CC).

CONCLUSION: The newly developed water jet device effectively removes biofilm from rough titanium surfaces in vitro and, in combination with the new CAP device, biologically acceptable surfaces allow osteoblasts to grow. WJ in combination with CAP leads to cleaner surfaces than the usage of curette and cotton swabs with or without subsequent plasma treatment. Our next step will be a clinical pilot study with these new devices to assess the clinical healing process.}, } @article {pmid35523645, year = {2022}, author = {Ma, CJ and He, Y and Jin, X and Zhang, Y and Zhang, X and Li, Y and Xu, M and Liu, K and Yao, Y and Lu, F}, title = {Light-regulated nitric oxide release from hydrogel-forming microneedles integrated with graphene oxide for biofilm-infected-wound healing.}, journal = {Biomaterials advances}, volume = {134}, number = {}, pages = {112555}, doi = {10.1016/j.msec.2021.112555}, pmid = {35523645}, issn = {2772-9508}, mesh = {Biofilms ; Graphite ; Humans ; *Hydrogels/pharmacology ; Nitric Oxide/chemistry ; Wound Healing ; *Wound Infection/drug therapy ; }, abstract = {Nitric oxide (NO) is an antimicrobial agent that possesses tissue-regenerating ability. However, it also has a short half-life and storage difficulties as disadvantages to its application. To overcome these limitations, a new type of hydrogel-forming microneedle (HFMN) is proposed that can be fabricated by integrating polyvinyl alcohol (PVA) hydrogels (a highly biocompatible drug carrier) with S-nitrosoglutathione (GSNO, a NO releasing agent), and graphene oxide (GO) at freezing temperatures (GO-GNSO-HFMNs). Results show that GSNO-GO-HFMNs release NO gradually with increasing temperature and, more importantly, can be warmed up by mild infrared irradiation to accelerate subcutaneous release of NO from the heat-sensitive GSNO. Biofilm-infected wounds often present obstacles to drug delivery, whereas the microneedle (MN) structure disrupts the biofilm and directly releases NO into the wound. This inhibits bacterial growth and increases tissue regeneration while shortening the healing time of biofilm-infected wounds. Therefore, this type of patch can be regarded as a novel, heat-sensitive, light-regulated, NO-releasing MN patch.}, } @article {pmid35521519, year = {2022}, author = {Cohen-Cymberknoh, M and Kolodkin-Gal, D and Keren-Paz, A and Peretz, S and Brumfeld, V and Kapishnikov, S and Suissa, R and Shteinberg, M and McLeod, D and Maan, H and Patrauchan, M and Zamir, G and Kerem, E and Kolodkin-Gal, I}, title = {Calcium carbonate mineralization is essential for biofilm formation and lung colonization.}, journal = {iScience}, volume = {25}, number = {5}, pages = {104234}, pmid = {35521519}, issn = {2589-0042}, abstract = {Biofilms are differentiated microbial communities held together by an extracellular matrix. μCT X-ray revealed structured mineralized areas within biofilms of lung pathogens belonging to two distant phyla - the proteobacteria Pseudomonas aeruginosa and the actinobacteria Mycobacterium abscessus. Furthermore, calcium chelation inhibited the assembly of complex bacterial structures for both organisms with little to no effect on cell growth. The molecular mechanisms promoting calcite scaffold formation were surprisingly conserved between the two pathogens as biofilm development was similarly impaired by genetic and biochemical inhibition of calcium uptake and carbonate accumulation. Moreover, chemical inhibition and mutations targeting mineralization significantly reduced the attachment of P. aeruginosa to the lung, as well as the subsequent damage inflicted by biofilms to lung tissues, and restored their sensitivity to antibiotics. This work offers underexplored druggable targets for antibiotics to combat otherwise untreatable biofilm infections.}, } @article {pmid35520625, year = {2022}, author = {Mashamba, TG and Adeosun, IJ and Baloyi, IT and Tshikalange, ET and Cosa, S}, title = {Quorum sensing modulation and inhibition in biofilm forming foot ulcer pathogens by selected medicinal plants.}, journal = {Heliyon}, volume = {8}, number = {4}, pages = {e09303}, pmid = {35520625}, issn = {2405-8440}, abstract = {The crisis of antibiotic resistance necessitates the search of phytochemicals as potential antibacterial, anti-quorum sensing and antibiofilm forming agents. For the present study, fifteen (15) selected medicinal plants were evaluated to inhibit the biological activities of multi-drug resistant (MDR) pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis) associated with diabetic foot ulcer. Antibacterial activities revealed noteworthy minimum inhibitory concentration (MIC) values ≤1 mg/mL for thirteen (13) out of the sixty (60) plant extracts screened. The potent extracts included Euclea natalensis ethyl acetate (0.25 mg/mL), Aloe ferox methanol (0.5 mg/ml) and Warburgia salutaris aqueous (0.5 mg/mL) extracts. Chemical profiling of the active extracts using gas chromatography-mass spectrometry (GC-MS) identified neophytadiene, guanosine, squalene, cis megastigma-5,8-diene-4-one and sorbitol as prevalent compounds among the active extracts. Anti-quorum sensing activities of E. natalensis (ethyl acetate), A. ferox (methanol) and W. salutaris (aqueous) extracts ranged from 4.81 - 58.34% with E. natalensis (ethyl-acetate) showing the highest activity. Molecular docking against CviR protein showed selected compounds having high docking scores with sorbitol showing the highest score of -7.04 kcal/mol. Warburgia salutaris aqueous extract exhibited the highest biofilm inhibition (73%) against E. coli. Euclea natalensis, Aloe ferox and Warburgia salutaris compounds act as antagonist of N-acyl homoserine lactone (AHL) signaling, thus may serve as candidates in antipathogenic and antibiofilm phytomedicine development for MDR foot ulcer bacterial pathogens.}, } @article {pmid35515126, year = {2022}, author = {Huang, J and Wu, Z and Xu, J}, title = {Effects of Biofilm Nano-Composite Drugs OMVs-MSN-5-FU on Cervical Lymph Node Metastases From Oral Squamous Cell Carcinoma.}, journal = {Frontiers in oncology}, volume = {12}, number = {}, pages = {881910}, pmid = {35515126}, issn = {2234-943X}, abstract = {This work was developed to the effects of biofilm composite nano-drug delivery system (OMVs-MSN-5-FU) on lymph node metastasis from oral squamous cell carcinoma. Mesoporous silica nanoparticles loaded with 5-FU (MSN-5-FU) were prepared first. Subsequently, the outer membrane vesicles (OMV) of Escherichia coli were collected to wrap MSN-5-FU, and then OMVs-MSN-5-FU was prepared. It was then immersed in artificial gastric juice and artificial intestinal juice to explore the drug release rate. Next, the effects of different concentrations of the nano-drug delivery systems on the proliferation activity of oral squamous carcinoma cell line KOSC-2 cl3-43 were analyzed. Tumor-bearing nude mice models were prepared by injecting human tongue squamous cell carcinoma cells Tca8113 into BALB/c-nu nude mice. They were injected with the OMVs-MSN-5-FU nano drug carrier system, and peri-carcinoma tissue and cervical lymph node tissue were harvested to observe morphological changes by Hematoxylin - eosin (HE) staining. The scanning electron microscope (SEM) results showed that all MSN, MSN-5-FU, OMV, and OMV-MSN-5-FU were spherical and uniformly distributed, with particle sizes of about 60nm, 80nm, 90nm, and 140nm, respectively. Among them, OMV had a directional core-shell structure. The cumulative drug release rates of artificial gastric juice in 48 hours were 61.2 ± 2.3% and 26.5 ± 3.1%, respectively. The 48 hours cumulative drug release rates of artificial intestinal juice were 70.5 ± 6.3% and 32.1 ± 3.8%, respectively. The cumulative release of MSN-5-FU was always higher than OMV-MSN-5-FU. The cumulative release of MSN-5-FU was always higher than OMV-MSN-5-FU. After injection of OMVS-MSN-5-FU, the number of cancer cells was significantly reduced and cervical lymph node metastasis was significantly controlled. HE staining results showed that OMVS-MSN-5-FU injection reduced the number of stained cells. Dense lymphocytes were clearly observed in the cortex of neck lymphocytes. The OMVs-MSN-5-FU drug delivery system can slow down the drug release rate, significantly inhibit the proliferation activity of oral squamous cancer cells, and control the metastasis of cancer cells to cervical lymph nodes.}, } @article {pmid35513339, year = {2022}, author = {Dietrich, PM and Kjærvik, M and Willneff, EA and Unger, WES}, title = {In-depth analysis of iodine in artificial biofilm model layers by variable excitation energy XPS and argon gas cluster ion sputtering XPS.}, journal = {Biointerphases}, volume = {17}, number = {3}, pages = {031002}, doi = {10.1116/6.0001812}, pmid = {35513339}, issn = {1559-4106}, mesh = {Argon/chemistry ; Biofilms ; Iodides ; *Iodine ; Photoelectron Spectroscopy ; Povidone ; *Povidone-Iodine ; Sepharose ; }, abstract = {Here, we present a study on agarose thin-film samples that represent a model system for the exopolysaccharide matrix of biofilms. Povidone-iodide (PVP-I) was selected as an antibacterial agent to evaluate our x-ray photoelectron spectroscopy (XPS)-based methodology to trace specific marker elements, here iodine, commonly found in organic matrices of antibiotics. The in-depth distribution of iodine was determined by XPS analyses with variable excitation energies and in combination with argon gas cluster ion beam sputter cycles. On mixed agarose/PVP-I nanometer-thin films, both methods were found to solve the analytical task and deliver independently comparable results. In the mixed agarose/PVP-I thin film, we found the outermost surface layer depleted in iodine, whereas the iodine is homogeneously distributed in the depth region between this outermost surface layer and the interface between the thin film and the substrate. Depletion of iodine from the uppermost surface in the thin-film samples is assumed to be caused by ultrahigh vacuum exposure resulting in a loss of molecular iodine (I2) as reported earlier for other iodine-doped polymers.}, } @article {pmid35512440, year = {2022}, author = {Li, Y and Sun, W and Wang, Q and Yu, Y and Wan, Y and Zhou, K and Guo, R and Han, X and Chen, Z and Fang, W and Jiang, W}, title = {The GntR-like transcriptional regulator HutC involved in motility, biofilm-forming ability, and virulence in Vibrio parahaemolyticus.}, journal = {Microbial pathogenesis}, volume = {167}, number = {}, pages = {105546}, doi = {10.1016/j.micpath.2022.105546}, pmid = {35512440}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Transcription Factors/genetics/metabolism ; *Vibrio parahaemolyticus/genetics ; Virulence/genetics ; }, abstract = {As a halophilic food-borne pathogen, Vibrio parahaemolyticus continueo be a major health issue worldwide. The pathogenic mechanisms of V. parahaemolyticus are still not fully understood. One of the most abundant and widely distributed groups of helix-turn-helix transcription factors is the GntR family of regulators, which are involved in the regulation of various biological processes in bacteria, but little is known about their functions in V. parahaemolyticus. Here, we identified a gene designated as hutC in V. parahaemolyticus SH112 that encodes a member belongs to the HutC subfamily of the large GntR transcriptional regulator family. Compared to the wild type, the hutC mutant strain was significantly more sensitive to acid, bile salt, Triton X-100, and sodium dodecyl sulfate stresses. Our results showed that HutC is required for optimal swimming motility but not necessary for the swarming of V. parahaemolyticus. In addition, inactivation of hutC in V. parahaemolyticus SH112 led to decreased biofilm formation, reduced cytotoxicity in Coca-2 cells, and defective virulence in vivo compared to the wild-type strain. Furthermore, transcriptome sequencing (RNA-Seq) analysis and real-time PCR indicated 4 upregulated and 14 downregulated genes in the hutC mutant strain. Functional analysis revealed that 4 upregulated genes were related to the histidine metabolism pathway. The 14 downregulated genes were mostly related to the cellular metabolic process, binding, and membrane part. This study presents evidence that HutC is involved in bacterial survival under conditions of stress, swimming motility, biofilm formation, cytotoxicity, virulence, and gene regulation of V. parahaemolyticus during infection.}, } @article {pmid35512342, year = {2022}, author = {Boncompagni, SR and Micieli, M and Di Maggio, T and Aiezza, N and Antonelli, A and Giani, T and Padoani, G and Vailati, S and Pallecchi, L and Rossolini, GM}, title = {Activity of fosfomycin/colistin combinations against planktonic and biofilm Gram-negative pathogens.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {8}, pages = {2199-2208}, doi = {10.1093/jac/dkac142}, pmid = {35512342}, issn = {1460-2091}, support = {//Zambon S.p.A./ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Colistin/pharmacology ; Drug Resistance, Multiple, Bacterial ; Drug Synergism ; *Fosfomycin/pharmacology ; Klebsiella pneumoniae ; Microbial Sensitivity Tests ; Plankton ; }, abstract = {OBJECTIVES: To investigate the in vitro activity of fosfomycin, colistin and combinations thereof against planktonic and biofilm cultures of Gram-negative pathogens, mostly showing MDR phenotypes, at concentrations achievable via inhalation of aerosolized drugs.

METHODS: Activity against planktonic cultures was tested by the chequerboard assay with 130 strains, including 52 Pseudomonas aeruginosa, 47 Klebsiella pneumoniae, 19 Escherichia coli, 7 Stenotrophomonas maltophilia and 5 Acinetobacter baumannii. Activity against biofilm cultures was tested by biofilm chequerboard and quantitative antibiofilm assays with a subset of 20 strains. In addition, 10 of these strains were tested in mutant prevention concentration (MPC) assays.

RESULTS: Against planktonic cultures, synergism between fosfomycin and colistin was detected with a minority (10%) of strains (eight K. pneumoniae and five P. aeruginosa), while antagonism was never observed. Synergism between fosfomycin and colistin against biofilms was observed with the majority of tested strains (16/20 in biofilm chequerboard assays, and 18/20 in the quantitative antibiofilm assays), including representatives of each species and regardless of their resistance genotype or phenotype. Furthermore, combination of fosfomycin and colistin was found to significantly reduce the MPC of individual drugs.

CONCLUSIONS: Fosfomycin and colistin in combination, at concentrations achievable via inhalation of nebulized drugs, showed notable synergy against MDR Gram-negative pathogens grown in biofilm, and were able to reduce the emergence of fosfomycin- and colistin-resistant subpopulations.}, } @article {pmid35511298, year = {2022}, author = {Jia, X and Liu, X and Zhu, K and Zheng, X and Yang, Z and Yang, X and Hou, Y and Yang, Q}, title = {Lysozyme regulates the extracellular polymer of activated sludge and promotes the formation of electroactive biofilm.}, journal = {Bioprocess and biosystems engineering}, volume = {45}, number = {6}, pages = {1065-1074}, pmid = {35511298}, issn = {1615-7605}, support = {No. 202017//Foundation of Qilu University of Technology of Cultivating Subject for Biology and Biochemistry/ ; No. S202010431030//National Innovation and Entrepreneurship Training Program for Local College Student/ ; No. S202010431046//National Innovation and Entrepreneurship Training Program for Local College Student/ ; }, mesh = {Biofilms ; *Extracellular Polymeric Substance Matrix ; Muramidase ; Polymers ; *Sewage/microbiology ; }, abstract = {The formation of electroactive biofilm from activated sludge on electrode surface is a key step to construct a bio-electrochemical system, yet it is greatly limited by the poor affinity between the bacteria and the electrode interface. Herein, we report a new method to promote the formation of electroactive biofilm by regulating the extracellular polymeric substance (EPS) content in activated sludge with lysozyme. The investigation of the effect of lysozyme treatment on the content of extracellular polymers and the biofilm formation of electroactive bacteria suggests that lysozyme can improve the permeability of the positive bacterial cell membrane and thus increase the EPS content in the activated sludge. The characterizations of electrochemical activity, surface morphology and community structure of the anode biofilm indicate that increasing EPS content promotes the adhesion of the mixed bacteria in the activated sludge on the electrode and results in denser biofilms with better conductivities. The microbial fuel cell (MFC) inoculated with the sludge of high EPS content exhibits the power density up to 2.195 W/m[2], much higher than that inoculated with the untreated sludge (1.545 W/m[2]). The strategy of adjusting EPS content in activated sludge with a biological enzyme can effectively enhance the ability of the bacterial community to form biofilms and exhibits great application potentials in the construction of high efficiency bio-electrochemical systems.}, } @article {pmid35511205, year = {2022}, author = {Patil, JS and D'souza, S}, title = {Dark survival in biofilm-forming microalgae: potential for colonizing benthic ecosystems.}, journal = {FEMS microbiology ecology}, volume = {98}, number = {6}, pages = {}, doi = {10.1093/femsec/fiac053}, pmid = {35511205}, issn = {1574-6941}, mesh = {Biofilms ; *Diatoms ; Ecosystem ; *Microalgae ; Seawater ; }, abstract = {The biofilm-forming microalgae are known to experience periods of continuous darkness (upto several days), in addition to the natural day-night cycle, especially in the intertidal sediment regions (when transported to deeper sediments) and the ships' ballast water tanks (during voyages). However, the information on community and physiological responses to different periods of darkness is limited. Here, the survival capability of biofilm-forming microalgae to varying periods of darkness (7-35 days) and the growth patterns upon resumption of normal 12 h light:dark photocycle has been addressed through simulation experiments. Diatoms dominated the seawater biofilms, but the dark survival period varied and was species-specific. Of the 25 diatoms, only Amphora, potential toxin producer, followed by Navicula remained viable and photosynthetically healthy under darkness without undergoing asexual reproduction. Both diatoms are essential contributors to fouling and microphytobenthic community. Upon re-exposure of dark-adapted biofilms to 12 h light:dark photocycle, the improvement in photosynthetic efficiency and resumption of growth via asexual-reproduction was observed. However, the lag-phase duration increased with a long dark history. Nevertheless, eurytolerant nature and high dark survival capability (with its quick response to light) of Amphora and Navicula indicated that they have the potential to colonize benthic-ecosystems thus impacting the benthic and fouling community.}, } @article {pmid35510054, year = {2022}, author = {Li, G and Wei, Y and Guo, Y and Gong, H and Lian, J and Xu, G and Bai, B and Yu, Z and Deng, Q}, title = {Omadacycline Efficacy against Streptococcus Agalactiae Isolated in China: Correlation between Resistance and Virulence Gene and Biofilm Formation.}, journal = {Computational intelligence and neuroscience}, volume = {2022}, number = {}, pages = {7636983}, pmid = {35510054}, issn = {1687-5273}, mesh = {*Biofilms ; China ; Multilocus Sequence Typing ; Retrospective Studies ; *Streptococcus agalactiae/genetics ; Tetracyclines ; Virulence/genetics ; }, abstract = {This study aimed to evaluate the activity, resistance, clonality of MIC distribution, and the correlation between virulence and resistance genes and biofilm formation of omadacycline (OMC) in clinics for Streptococcus agalactiae isolates from China. 162 isolates were collected retrospectively in China. The S. agalactiae were collected from the body's cervical secretions, wound secretions, ear swabs, secretions, semen, venous blood, cerebrospinal fluid, pee, etc. The MIC of OMC against S. agalactiae was determined by broth microdilution. The inhibition zone diameters of OMC and other common antibiotics were measured using filter paper. D-test was performed to determine the phenotype of cross resistance between erythromycin and clindamycin. In Multilocus sequence typing (MLST), some commonly-detected resistance genes and virulence gene of these S. agalactiae isolates were investigated using polymerase chain reaction (PCR). Biofilms were detected by crystal violet staining. Our data demonstrated the correalation of the biofilm formation and OMA antimicrobial susceptibility of S.agalactiae clinical isolates with the carrier of virulence gene scpB. Conclusively, OMC exhibits the robust antimcirobial activity against clinical S. agalactiae isolates from China compared with DOX or MIN, and the carrier of the virulence gene scpB might correlate with the biofilm formation in OMC-resistant S. agalactiae.}, } @article {pmid35508743, year = {2022}, author = {ElBaradei, A and Yakout, MA}, title = {Stenotrophomonas maltophilia: Genotypic Characterization of Virulence Genes and The Effect of Ascorbic Acid on Biofilm Formation.}, journal = {Current microbiology}, volume = {79}, number = {6}, pages = {180}, pmid = {35508743}, issn = {1432-0991}, mesh = {Ascorbic Acid/pharmacology ; Biofilms ; *Gram-Negative Bacterial Infections/microbiology ; Humans ; *Stenotrophomonas maltophilia/genetics ; Virulence/genetics ; }, abstract = {Stenotrophomonas maltophilia is an environmental bacterium that has gained a lot of attention, as a nosocomial pathogen associated with significant mortality rates. Biofilm formation is considered the corner stone for establishing infections in many bacteria including S. maltophilia. The aim of this study was the genotypic characterization of the different virulence-associated genes and the investigation of the effect of ascorbic acid on S. maltophilia biofilm formation. A total of 20 S. maltophilia isolates from different sources were included in this study. Genes encoding different virulence factors were investigated genotypically. These included stmPr1, stmPr2, smlt3773 locus, smf-1, rpfF, rmlA and spgM. Biofilm formation was investigated phenotypically. The effect of ascorbic acid on biofilm formation was investigated using MIC as well as sub-inhibitory concentrations. Many of the isolates harbored both serine proteases genes stmPr-1 and stmPr-2. Fourteen (70%) of the 20 isolates carried stmPr-1 and 15 (75%) had stmPr-2. Most of the isolates (95%) possessed smlt-3773 locus. Genes linked to biofilm formation such as smf-1, rpfF, rmlA and spgM, were found in (90%), (45%), (85%) and (30%) of the isolates, respectively. Phenotypically, all S. maltophilia isolates (100%) were biofilm producers. Fifteen (75%) were strong biofilm producers and 5 (25%) were moderate biofilm producers. In attempts to seek a non-chemotherapeutic alternative that can hinder biofilm formation without provoking antimicrobial resistance, the results, herein, showed that ascorbic acid inhibits biofilm formation in a dose-dependent manner.}, } @article {pmid35508567, year = {2022}, author = {Keymaram, M and Falahati, M and Farahyar, S and Lotfali, E and Abolghasemi, S and Mahmoudi, S and Sadeghi, F and Khalandi, H and Ghasemi, R and Shamsaei, S and Raiesi, O}, title = {Anti-biofilm properties of eucalyptol in combination with antifungals against Candida albicans isolates in patients with hematological malignancy.}, journal = {Archives of microbiology}, volume = {204}, number = {6}, pages = {295}, pmid = {35508567}, issn = {1432-072X}, support = {IR.IUMS.FMD.REC.1399.393.//Iran University of Medical Sciences/ ; }, mesh = {Adult ; Amphotericin B/pharmacology/therapeutic use ; Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; Candida ; Candida albicans ; *Candidiasis, Oral/drug therapy ; Eucalyptol ; Female ; *Hematologic Neoplasms/complications/drug therapy ; Humans ; Itraconazole/pharmacology ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Nystatin/pharmacology ; }, abstract = {Oral candidiasis is a fungal infection caused mainly by Candida albicans and it is a major problem among hematologic malignancy patients. Biofilm formation is an attributable factor to both virulence and drug resistance of Candida species. The aim of the study was to evaluate the biofilm-producing ability of oral C. albicans isolates and to evaluate the inhibitory activity of eucalyptol on Candida biofilm, alone and in combination with antifungal agents. Samples were collected from the oral cavity of 106 patients with hematologic malignancy. The isolated yeasts were identified by PCR-sequencing. Then C. albicans isolates were analyzed for their biofilm-producing ability by crystal violet staining and MTT assay. The minimum biofilm inhibition concentrations (MBIC) of eucalyptol, amphotericin B, itraconazole, and nystatin and the in vitro interaction of eucalyptol with these drugs were tested according to CLSI-M-27-A3 protocol and checkerboard methods, respectively. From 106 patients, 50 (47.2%) were confirmed for oral candidiasis [mean ± SD age 39 ± 14 years; female 31 (62%) and male 19 (38%)]. C. albicans was isolated from 40 of 50 (80%) patients. From 40 C. albicans isolates, 24 (60%) and 16 (40%) were moderate and weak biofilm producer, respectively. The geometric mean MBIC of amphotericin B, itraconazole, nystatin and eucalyptol were 3.93 µg/mL, 12.55 µg/mL, 0.75 µg/mL and 798 µg/mL, respectively. Eucalyptol interacted synergistically with amphotericin B, itraconazole and nystatin against 12.5, 10, and 22.5% of isolates, respectively. Eucalyptol demonstrated promising activity against biofilm of C. albicans when tested alone or combined with antifungal drugs.}, } @article {pmid35508261, year = {2022}, author = {Cao, X and Yuan, Y and Khodseewong, S and Nishimura, O and Wang, H and Li, X}, title = {Efficient use of electrons in a double-anode microbial fuel cell-biofilm electrode reactor self-powered coupled system for degradation of azo dyes.}, journal = {Chemosphere}, volume = {302}, number = {}, pages = {134760}, doi = {10.1016/j.chemosphere.2022.134760}, pmid = {35508261}, issn = {1879-1298}, mesh = {Azo Compounds/chemistry ; *Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Electrons ; }, abstract = {A coupled system consisting of a double-anode microbial fuel cell (MFC) unit and a biofilm electrode reactor (BER) has been applied to degrade the azo dye reactive brilliant red X-3B. In this system, the MFC effluent was used as the input of the BER. The MFC preliminarily degraded X-3B while generating electricity, and the BER obtained electrons from the MFC through the external circuit to continue degrading pollutants without the need for an external power supply. The X-3B removal efficiency was 41.93% higher in the coupled system than the control when the X-3B concentration was 3000 mg/L. The analysis of intermediate products showed that the azo bond of X-3B broke in the MFC, generating a large number of complex intermediates such as anthraquinones, which were further degraded into simple organic compounds in the BER. Meanwhile, the abundance of microbial taxa related to the degradation of refractory organics in the MFC was high, as was that of microbial taxa related to the degradation of simple organics in the BER. Furthermore, the abundance of microorganisms related to power generation in the MFC increased. These results provided an efficient strategy for improving electron utilization efficiency in the coupling system of bioelectrochemical system.}, } @article {pmid35507795, year = {2022}, author = {Khan, F}, title = {Strategies for Controlling Biofilm-forming Microbial Pathogens on Biotic and Abiotic Surfaces.}, journal = {Current drug targets}, volume = {23}, number = {10}, pages = {956-959}, doi = {10.2174/1389450123666220429115255}, pmid = {35507795}, issn = {1873-5592}, mesh = {*Biofilms ; Humans ; }, } @article {pmid35507525, year = {2022}, author = {Mayorga-Martinez, CC and Zelenka, J and Klima, K and Mayorga-Burrezo, P and Hoang, L and Ruml, T and Pumera, M}, title = {Swarming Magnetic Photoactive Microrobots for Dental Implant Biofilm Eradication.}, journal = {ACS nano}, volume = {16}, number = {6}, pages = {8694-8703}, doi = {10.1021/acsnano.2c02516}, pmid = {35507525}, issn = {1936-086X}, mesh = {*Titanium ; *Dental Implants ; Surface Properties ; Biofilms ; Magnetic Phenomena ; }, abstract = {Titanium dental implants are a multibillion dollar market in the United States alone. The growth of a bacterial biofilm on a dental implant can cause gingivitis, implant loss, and expensive subsequent care. Herein, we demonstrate the efficient eradication of dental biofilm on titanium dental implants via swarming magnetic microrobots based on ferromagnetic (Fe3O4) and photoactive (BiVO4) materials through polyethylenimine micelles. The ferromagnetic component serves as a propulsion force using a transversal rotating magnetic field while BiVO4 is the photoactive generator of reactive oxygen species to eradicate the biofilm colonies. Such photoactive magnetically powered, precisely navigated microrobots are able to destroy biofilm colonies on titanium implants, demonstrating their use in precision medicine.}, } @article {pmid35507414, year = {2022}, author = {Cui, S and Qiao, J and Xiong, MP}, title = {Antibacterial and Biofilm-Eradicating Activities of pH-Responsive Vesicles against Pseudomonas aeruginosa.}, journal = {Molecular pharmaceutics}, volume = {19}, number = {7}, pages = {2406-2417}, doi = {10.1021/acs.molpharmaceut.2c00165}, pmid = {35507414}, issn = {1543-8392}, support = {R01 DK099596/DK/NIDDK NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests ; Polymers/chemistry ; *Pseudomonas aeruginosa ; }, abstract = {The formation of biofilms by a microcolony of bacteria is a significant burden on the healthcare industry due to difficulty eradicating it. In this study, pH-responsive vesicles capable of releasing apramycin (APR), a model aminoglycoside antibiotic, in response to the low pH typical of establishedPseudomonas aeruginosa biofilms resulted in improved eradication of existing biofilms in comparison to the free drug. The amphiphilic polymeric vesicle (PV) comprised of block polymer poly (ethylene glycol)-block-poly 2-(dimethylamino) ethyl methacrylate (mPEG-b-pDEAEMA) averaged 128 nm. The drug encapsulation content of APR in PV/APR was confirmed to be 28.2%, and the drug encapsulation efficiency was confirmed to be 51.2%. At pH 5.5, PV/APR released >90% APR after 24 h compared to <20% at pH 7.4. At pH 5.5, protonation of the pDEAEMA block results in a zeta potential of +23 mV compared to a neutral zeta potential of +2.2 mV at pH 7.4. Confocal microscopy, flow cytometry, and scanning electron microscopy reveal that the positively charged vesicles can compromise the integrity of the planktonic bacterial membrane in a pH-dependent manner. In addition, PV/APR is able to diffuse into mature biofilms to release APR in the acidic milieu of biofilm bacteria, and PV/APR was more efficient at eliminating preexisting biofilms compared to free APR at 128 and 256 μg/mL. This study reveals that dynamic charge density in response to pH can lead to differential levels of interactions with the biofilm and bacterial membrane. This effectively results in enhanced antibacterial and antibiofilm properties against both planktonic and difficult-to-treat biofilm bacteria at concentrations significantly lower than those of the free drug. Overall, this pH-responsive vesicle could be especially promising for treating biofilm-associated infectious diseases.}, } @article {pmid35507240, year = {2022}, author = {Shukla, SK and Manobala, T and Rao, TS}, title = {The role of S-layer protein (SlpA) in biofilm-formation of Deinococcus radiodurans.}, journal = {Journal of applied microbiology}, volume = {133}, number = {2}, pages = {796-807}, doi = {10.1111/jam.15613}, pmid = {35507240}, issn = {1365-2672}, mesh = {Bacterial Proteins/metabolism ; Biofilms ; *Deinococcus/genetics/metabolism ; Plasmids/genetics ; }, abstract = {AIMS: To investigate the molecular basis of biofilm formation in a recombinant lab strain of Deinococcus radiodurans with a plasmid harbouring gfp and kan[R] that acquired the biofilm-forming ability.

METHODS AND RESULTS: Deinococcus radiodurans R1 is known as a nonbiofilm former bacterium and so far there are no reports on its biofilm-producing capabilities. In this study, we investigated the molecular basis of biofilm formation in a recombinant strain of D. radiodurans using classical biofilm assays, confocal laser scanning microscopy and real-time PCR. Biochemical analysis of D. radiodurans biofilm matrix revealed that it consisted predominantly of protein and carbohydrate complexes with a little amount of extracellular DNA (eDNA). Furthermore, studies showed that D. radiodurans biofilm formation was enhanced in the presence of 25 mM Ca[2+] , which enhanced the exopolysaccharide and protein content in the biofilm matrix. Enzymatic treatments with proteinase K, alginate lyase and DNase I indicated the involvement of some proteinaceous components to be critical in the biofilm formation. RT-PCR studies showed that increased expression of a surface layer protein SlpA conferred the biofilm ability to D. radiodurans.

CONCLUSION: Overexpression of SlpA in D. radiodurans conferred the biofilm formation ability to the bacterium, in which a partial role was also played by the recombinant plasmid pKG. It was also shown that the presence of Ca[2+] in the growth medium enhanced SlpA production, thus improving biofilm stability and biofilm maturation of D. radiodurans.

SIGNIFICANCE AND IMPACT: This study shows how biofilm formation can be augmented in D. radiodurans. The finding has implications for the development of D. radiodurans biofilm-based biotechnological applications.}, } @article {pmid35506966, year = {2022}, author = {Abdul Azees, PA and Wang, H and Chen, XD and Yeh, CK and Garcia-Godoy, F}, title = {In vitro effect of an oral spray and mouthrinses on dual species cariogenic bacteria biofilm.}, journal = {American journal of dentistry}, volume = {35}, number = {2}, pages = {103-108}, pmid = {35506966}, issn = {0894-8275}, mesh = {*Biofilms ; Dental Enamel ; Humans ; Mouthwashes/pharmacology ; Oral Sprays ; *Streptococcus mutans ; }, abstract = {PURPOSE: To determine the efficacy of an oral spray and oral rinses to inhibit oral cariogenic dual species biofilm formation on hydroxyapatite (HA) discs.

METHODS: The Streptococcus mutans (NCTC 10449, ATCC), Lactobacilli casei (NCIB 8820, ATCC) dual species biofilm formation and inhibition on HA disc was tested using five antimicrobial products, i.e., oral spray (Oral Shield), Mouthrinse (Listerine Ultra Clean, Listerine Cool Mint, Crest Pro-Health, ACT Restoring). An untreated group served as control. The established biofilm on the surface of each disc was treated or untreated with oral spray and mouthrinse for 2 minutes after 24 or 48 hours. The dual species biofilm formation and inhibition on HA discs was determined using the spread plate method and colonies were counted and expressed as colony forming units (CFU/mL). Further, the HA disc was subjected to confocal laser scanning microscope (CLSM) examination to determine the viability of cells using live-dead staining and a scanning electron microscope (SEM) to examine the effect on bacteria biofilm and morphology. The cytotoxic effect of test spray and mouthrinse was tested on OKF6/TERT-2 cells using the MTT method.

RESULTS: At each time point, 24- or 48-hours, S. mutans and L. casei mixed biofilm on HA discs had a significantly (P> 0.001) fewer number of bacteria in the treated groups than the untreated one. The oral spray and mouthrinses had a detrimental effect on bacteria biofilm, morphology and cell wall, whereas no significant changes were observed in the untreated group. Cytotoxic assay revealed that the oral spray was safe for human oral keratinocyte cells.

CLINICAL SIGNIFICANCE: The tested oral spray could offer potential to inhibit the cariogenic bacteria and protect the tooth enamel from cariogenic bacterial biofilm.}, } @article {pmid35505905, year = {2022}, author = {Visperas, A and Santana, D and Ju, M and Milbrandt, NB and Tsai, YH and Wickramasinghe, S and Klika, AK and Piuzzi, NS and Samia, ACS and Higuera-Rueda, CA}, title = {Standardized quantification of biofilm in a novel rabbit model of periprosthetic joint infection.}, journal = {Journal of bone and joint infection}, volume = {7}, number = {2}, pages = {91-99}, pmid = {35505905}, issn = {2206-3552}, abstract = {Periprosthetic joint infection (PJI) is one of the most devastating complications of total joint arthroplasty. The underlying pathogenesis involves the formation of bacterial biofilm that protects the pathogen from the host immune response and antibiotics, making eradication difficult. The aim of this study was to develop a rabbit model of knee PJI that would allow reliable biofilm quantification and permit the study of treatments for PJI. In this work, New Zealand white rabbits (n = 19) underwent knee joint arthrotomy, titanium tibial implant insertion, and inoculation with Xen36 (bioluminescent Staphylococcus aureus) or a saline control after capsule closure. Biofilm was quantified via scanning electron microscopy (SEM) of the tibial explant 14 d after inoculation (n = 3 noninfected, n = 2 infected). Rabbits underwent debridement, antibiotics, and implant retention (DAIR) (n = 6) or sham surgery (n = 2 noninfected, n = 6 infected) 14 d after inoculation, and they were sacrificed 14 d post-treatment. Tibial explant and periprosthetic tissues were examined for infection. Laboratory assays supported bacterial infection in infected animals. No differences in weight or C-reactive protein (CRP) were detected after DAIR compared to sham treatment. Biofilm coverage was significantly decreased with DAIR treatment when compared with sham treatment (61.4 % vs. 90.1 %, p < 0 .0011) and was absent in noninfected control explants. In summary, we have developed an experimental rabbit hemiarthroplasty knee PJI model with bacterial infection that reliably produces quantifiable biofilm and provides an opportunity to introduce treatments at 14 d. This model may be used to better understand the pathogenesis of this condition and to measure treatment strategies for PJI.}, } @article {pmid35503968, year = {2022}, author = {Ramidan, JC and de Mendonça E Bertolini, M and Júnior, MRM and Portela, MB and Lourenço, EJV and de Moraes Telles, D}, title = {Filling Materials Efficacy on Preventing Biofilm Formation Inside Screw Access Channels of Implant Abutments.}, journal = {The Journal of oral implantology}, volume = {48}, number = {6}, pages = {573-577}, doi = {10.1563/aaid-joi-D-20-00191}, pmid = {35503968}, issn = {0160-6972}, mesh = {*Gutta-Percha ; *Dental Implants/microbiology ; Bone Screws ; Polytetrafluoroethylene ; Biofilms ; }, abstract = {The choice of the material used to fill screw access channels in implant-supported prostheses depends, in most cases, on operator's preference, without considering the susceptibility of biofilm colonization. Therefore, the aim of this study was to determine and compare the total amount of biofilm formed on different materials used to fill screw access channels in implant abutments. For this propose, titanium implant analogs were attached on abutments and divided into 5 groups: positive control (no filling material); negative control (closed with resin); and filled with cotton, gutta-percha, or polytetrafluoroethylene (PTFE). The analogs with attached abutments were then immersed in a brain heart infusion medium containing Candida albicans (strain 10231 from American Type Culture Collection [ATCC]) and incubated aerobically at 37°C with gentle agitation. After 15 days, materials were removed, and total viable biofilm on each material was quantified by methyl tetrazolium reduction assay at 490 nm. All experiments were performed in triplicate. Data were processed by IBM SPSS Statistic software using 1-way analysis of variance and Bonferroni post hoc tests to analyze differences between groups, with an overall significance level of P < .001. A significant difference was observed between cotton and gutta-percha (P < .017) and between cotton and PTFE (P < .025). However, there was no statistical difference between gutta-percha and PTFE (P > .050). Thus, this in vitro experiment showed that gutta-percha and PTFE presented lower biofilm formation compared with cotton when used to fill screw access channels. These results can provide a basis for future clinical studies that can be a guide to decreasing the occurrence of gaps and bacterial growth inside the implant/abutment attachment site. In addition, controlled in vivo studies are necessary to confirm the clinical viability of findings of this study.}, } @article {pmid35503533, year = {2022}, author = {Leshem, T and Schnall, BS and Azrad, M and Baum, M and Rokney, A and Peretz, A}, title = {Incidence of biofilm formation among MRSA and MSSA clinical isolates from hospitalized patients in Israel.}, journal = {Journal of applied microbiology}, volume = {133}, number = {2}, pages = {922-929}, pmid = {35503533}, issn = {1365-2672}, mesh = {Biofilms ; Humans ; Incidence ; Israel ; *Methicillin-Resistant Staphylococcus aureus/genetics ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics ; }, abstract = {AIM: To assess the biofilm-producing capacities of Staphylococcus aureus strains isolated from hospitalized patients in Israel.

METHODS AND RESULTS: A total of 16 S. aureus (80 MRSA and 83 MSSA) from screening (nasal swab) and clinical samples (blood and wounds) were characterized. Biofilm-producing capacities were determined using two different biofilm detection assays: Congo Red agar (CRA) and microtiter plate (MtP). In addition, a real-time PCR analysis was performed to detect the presence of biofilm-associated genes (icaA and icaD) and mecA gene. The two assays showed similar biofilm production pattern (28.2% agreement). MRSA strains tended to be greater biofilm-producers than MSSA strains. The presence of mecA was associated with biofilm production (p = 0.030). Additionally, bacteria isolated from blood samples produced less biofilm compared to those from other sources. Finally, no association was found between icaA and icaD presence and biofilm production.

CONCLUSION: This study supports earlier assumptions that biofilm formation depends strongly on environmental conditions.

This study significantly improved our knowledge on the biofilm production capacity of S. aureus strains in Israel. Moreover, it revealed an association between the mecA gene and biofilm production. Finally, this study underscores the importance of further research to evaluate risk factors for biofilm production.}, } @article {pmid35500834, year = {2022}, author = {Fu, HM and Wang, J and Ren, H and Ding, L}, title = {Acceleration of start-up of moving bed biofilm reactor at low temperature by adding specialized quorum sensing bacteria.}, journal = {Bioresource technology}, volume = {358}, number = {}, pages = {127249}, doi = {10.1016/j.biortech.2022.127249}, pmid = {35500834}, issn = {1873-2976}, mesh = {Acceleration ; Bacteria/genetics ; *Biofilms ; Bioreactors/microbiology ; *Nitrification ; Quorum Sensing ; Temperature ; Waste Disposal, Fluid/methods ; }, abstract = {This study aims to accelerate biofilm formation and operational performance of moving bed biofilm reactor (MBBR) at 5 ℃ by adding specialized Quorum Sensing bacteria (sphingomonas rubra BH3[T]). Results showed that bio augmented MBBR (RS) achieved a higher chemical oxygen demand and NH4[+]-N removal rate (93% and 75%), which in accordance with its increased biofilm thickness, higher biofilm activity, and nitrifying bacteria abundance (Nitrospira). The increased biofilm thickness (60.23 %) during the whole operating time, accompanied by more potent adhesion force (61.59 %), was related to increased polysaccharides and proteins in the biofilm. Pyrosequencing analysis indicated that BH3[T] contributed to higher species richness and triggered the rapid growth of precursor microorganisms (Nakamurella, Micropruina, and Zoogloea) and the enrichment of multifunctional microorganisms (Pseudomonas, Aeromonas, Arcobacter, Dechloromonas, and Flavobacterium) at low temperatures. This study provides an economical and practical new insight into accelerating start-up of MBBR system at low temperature.}, } @article {pmid35499217, year = {2022}, author = {Shahroodian, S and Mirshekar, M and Talebi, M and Torki, A and Amirmozafari, N}, title = {Association between virulence factors and biofilm formation in Enterococcus faecalis isolated from semen of infertile men.}, journal = {American journal of reproductive immunology (New York, N.Y. : 1989)}, volume = {88}, number = {1}, pages = {e13561}, doi = {10.1111/aji.13561}, pmid = {35499217}, issn = {1600-0897}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Enterococcus faecalis/genetics ; Humans ; *Infertility ; Male ; Microbial Sensitivity Tests ; Semen ; Virulence Factors/genetics ; }, abstract = {PROBLEM: Enterococcus faecalis is a common microbial semen contaminant. Although virulence factors and biofilm formation have often been analyzed in Enterococcus spp., there is little information about these features in isolates obtained from the genitourinary tract. This study was intended to characterize and determine the relationship between biofilm-forming ability and the presence of E. faecalis virulence factors isolated from human semen.

METHOD OF STUDY: A total of 32 patients diagnosed with primary infertility and 28 healthy men were included in the study. Semen analyses were performed according to the WHO guidelines. PCR reactions were applied for the detection of ace, esp, efeA, gelE, asa1, and cylA genes. Microtiter plate assay, via measurement of OD560, was used to measure the biofilm-forming ability of the isolates.

RESULTS: Sixty E. faecalis isolates from semen of infertile and fertile men were characterized by phenotypic and genotypic methods. The prevalence of ace, esp, efeA, gelE, asa1 and cylA were reported to be 81.3%/100.0%, 81.3%/89.3%, 81.3%/85.7%, 71.9%/53.6%, 8.8%/75.0%, and 62.5%/67.9% in infertile/fertile groups; respectively. Strong, weak, and non-biofilm reactions were reported to be 50.0%/21.4%, 40.6%/64.3%, and 9.4%/14.3% in infertile and fertile groups; respectively.

CONCLUSIONS: There was a significant relationship between fertility and weak biofilm reaction and also between biofilm formation and possession of the esp gene (P < .05). It could be speculated that colonization with E. faecalis with a strong ability for biofilm formation could become a potential threat to men's fertility.}, } @article {pmid35495696, year = {2022}, author = {Li, M and Wang, Z and Zhou, M and Zhang, C and Zhi, K and Liu, S and Sun, X and Wang, Z and Liu, J and Liu, D}, title = {Continuous Production of Human Epidermal Growth Factor Using Escherichia coli Biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {855059}, pmid = {35495696}, issn = {1664-302X}, abstract = {Increasing demand for recombinant proteins necessitates efficient protein production processes. In this study, a continuous process for human epidermal growth factor (hEGF) secretion by Escherichia coli was developed by taking advantage of biofilm formation. Genes bcsB, fimH, and csgAcsgB that have proved to facilitate biofilm formation and some genes moaE, yceA, ychJ, and gshB potentially involved in biofilm formation were examined for their effects on hEGF secretion as well as biofilm formation. Finally, biofilm-based fermentation processes were established, which demonstrated the feasibility of continuous production of hEGF with improved efficiency. The best result was obtained from ychJ-disruption that showed a 28% increase in hEGF secretion over the BL21(DE3) wild strain, from 24 to 32 mg/L. Overexpression of bcsB also showed great potential in continuous immobilized fermentation. Overall, the biofilm engineering here represents an effective strategy to improve hEGF production and can be adapted to produce more recombinant proteins in future.}, } @article {pmid35495689, year = {2022}, author = {Chang, C and Yu, X and Guo, W and Guo, C and Guo, X and Li, Q and Zhu, Y}, title = {Bacteriophage-Mediated Control of Biofilm: A Promising New Dawn for the Future.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {825828}, pmid = {35495689}, issn = {1664-302X}, abstract = {Biofilms are complex microbial microcolonies consisting of planktonic and dormant bacteria bound to a surface. The bacterial cells within the biofilm are embedded within the extracellular polymeric substance (EPS) consisting mainly of exopolysaccharides, secreted proteins, lipids, and extracellular DNA. This structural matrix poses a major challenge against common treatment options due to its extensive antibiotic-resistant properties. Because biofilms are so recalcitrant to antibiotics, they pose a unique challenge to patients in a nosocomial setting, mainly linked to lower respiratory, urinary tract, and surgical wound infections as well as the medical devices used during treatment. Another unique property of biofilm is its ability to adhere to both biological and man-made surfaces, allowing growth on human tissues and organs, hospital tools, and medical devices, etc. Based on prior understanding of bacteriophage structure, mechanisms, and its effects on bacteria eradication, leading research has been conducted on the effects of phages and its individual proteins on biofilm and its role in overall biofilm removal while also revealing the obstacles this form of treatment currently have. The expansion in the phage host-species range is one that urges for improvement and is the focus for future studies. This review aims to demonstrate the advantages and challenges of bacteriophage and its components on biofilm removal, as well as potential usage of phage cocktail, combination therapy, and genetically modified phages in a clinical setting.}, } @article {pmid35493738, year = {2022}, author = {Sass, G and Marsh, JJ and Shrestha, P and Sabino, R and Stevens, DA}, title = {Synergy Between Pseudomonas aeruginosa Filtrates And Voriconazole Against Aspergillus fumigatus Biofilm Is Less for Mucoid Isolates From Persons With Cystic Fibrosis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {817315}, pmid = {35493738}, issn = {2235-2988}, mesh = {Aspergillus fumigatus/metabolism ; Biofilms ; *Coinfection ; *Cystic Fibrosis/complications/microbiology ; Humans ; Pseudomonas aeruginosa/metabolism ; Voriconazole/pharmacology ; }, abstract = {Persons with cystic fibrosis (CF) frequently suffer from Pseudomonas aeruginosa and Aspergillus fumigatus co-infections. There is evidence that co-infections with these interacting pathogens cause airway inflammation and aggravate deterioration of lung function. We recently showed that P. aeruginosa laboratory isolates synergistically interact with the anti-fungal azole voriconazole (VCZ), inhibiting biofilm metabolism of several A. fumigatus laboratory strains. Interaction was usually mediated via pyoverdine, but also via pyocyanin or pyochelin. Here we used planktonic filtrates of 7 mucoid and 9 non-mucoid P. aeruginosa isolates from CF patients, as well as 8 isolates without CF origin, and found that all of these isolates interacted with VCZ synergistically at their IC50 as well as higher dilutions. CF mucoid isolates showed the weakest interactive effects. Four non-mucoid P. aeruginosa CF isolates produced no or very low levels of pyoverdine and did not reach an IC50 against forming A. fumigatus biofilm; interaction with VCZ still was synergistic. A VCZ-resistant A. fumigatus strain showed the same level of susceptibility for P. aeruginosa anti-fungal activity as a VCZ-susceptible reference strain. Filtrates of most Pseudomonas isolates were able to increase anti-fungal activity of VCZ on a susceptible A. fumigatus strain. This was also possible for the VCZ-resistant strain. In summary these data show that clinical P. aeruginosa isolates, at varying degrees, synergistically interact with VCZ, and that pyoverdine is not the only molecule responsible. These data also strengthen the idea that during co-infections of A. fumigatus and P. aeruginosa lower concentrations of VCZ might be sufficient to control fungal growth.}, } @article {pmid35491280, year = {2022}, author = {Taşkın Kafa, AH and Hasbek, M}, title = {Synergistic efficacy of meropenem, ciprofloxacin and colistin antibiotics against planktonic and biofilm forms of Myroides odoratimimus bacterial isolates.}, journal = {Indian journal of medical microbiology}, volume = {40}, number = {3}, pages = {399-403}, doi = {10.1016/j.ijmmb.2022.04.004}, pmid = {35491280}, issn = {1998-3646}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; *Ciprofloxacin/pharmacology ; Colistin/pharmacology ; *Flavobacteriaceae/drug effects ; Humans ; Meropenem/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {PURPOSE: In this study, it was aimed to investigate the combined synergistic efficacy of colistin (CT), meropenem (MEM), and ciprofloxacin (CIP) antibiotics on planktonic and biofilm forms in Myroidesodoratimimus strains isolated from various clinical specimens.

METHODS: Antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method. In addition, minimum inhibitory concentrations (MIC) of CIP, MEM, and CT were studied using the standardized broth microdilution method. In vitro synergistic activity of antibiotics against M. odoratimimus planktonic bacteria strains was studied by the Micro Broth Checkerboard method. The microtiter plate (MtP) method was used to determine the effectiveness of antibiotics on M. odoratimimus biofilm formation.

RESULTS: A zone of inhibition was not observed against other antibiotics used except amikacin and linezolid in all strains. While CT/MEM and CT/CIP combinations have a synergistic effect on all strains, the combination CIP/MEM has an additive effect. According to the biofilm inhibition results, all three antibiotics inhibited biofilm formation. However, the efficacy of MEM (60.3-76.5%) and CIP (60.2-77.8%) was approximately two times higher than that of CT (25.4-34.5%). In addition, the effectiveness of combinations of antibiotics on biofilm formation was examined and the percentage of inhibition was 30.8% when CT was used alone, while the biofilm inhibition rates of CT/MEM and CT/CIP were 92.4% and 91.7%, respectively. MEM/CIP combination was inhibited biofilm formation by 75.7%.

CONCLUSIONS: This study is the first report showing the efficacy of CT, MEM and CIP antibiotics, which are frequently used in clinical practice, in combination on M. odoratimimus planktonic and biofilm forms. The findings of our study are particularly guiding for combined antibiotic treatment options in immunosuppressed patients admitted to an intensive care unit (ICU). The CT/MEM combination is currently used frequently. In addition, these results are important in terms of supporting in vitro that CT/CIP and MEM/CIP combinations can also be used as a treatment option in M. odoratimimus related infections.}, } @article {pmid35489461, year = {2022}, author = {Xia, Y and Lu, D and Qi, Y and Chen, H and Zhao, Y and Bai, Y and Zhu, L and Geng, N and Xu, C and Hua, E}, title = {Removal of nitrate from agricultural runoff in biochar electrode based biofilm reactor: Performance and enhancement mechanisms.}, journal = {Chemosphere}, volume = {301}, number = {}, pages = {134744}, doi = {10.1016/j.chemosphere.2022.134744}, pmid = {35489461}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Charcoal ; *Denitrification ; Electrodes ; *Nitrates ; Nitrogen/chemistry ; Nitrogen Oxides ; }, abstract = {A biochar electrode based biofilm reactor was developed for advanced removal of nitrate from agricultural runoff. The corn-straw (Zea mays L.) biochar formed at 500 °C has an adsorption capacity of NO3[-]-N up to 2.659 mg g[-1]. After 45-day start-up phase, the removal efficiency of nitrate reached 93.4% when impressed current was 20 mA, hydraulic retention time was 12 h and chemical oxygen demand/total nitrogen (C/N) ratio was 0.56 without additional carbon source. In comparison, neither electrochemical reduction alone nor microbial denitrification alone could obtain the ideal nitrate removal efficiency. The results implied that bio-electrochemical reduction was the main way of nitrate removal in the biofilm electrode reactor (BER). The denitrification efficiency of 88.9% could still be obtained when C/N = 0. It is because biochar can significantly promote the utilization efficiency of cathode electrons by microorganisms. Thus, biochar is a promising electrode material, which provides a new idea for the optimization of BER.}, } @article {pmid35487949, year = {2022}, author = {Tsagkari, E and Connelly, S and Liu, Z and McBride, A and Sloan, WT}, title = {The role of shear dynamics in biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {33}, pmid = {35487949}, issn = {2055-5008}, mesh = {Bacteria ; *Biofilms ; *Drinking Water ; Stress, Mechanical ; }, abstract = {There is growing evidence that individual bacteria sense and respond to changes in mechanical loading. However, the subtle responses of multispecies biofilms to dynamic fluid shear stress are not well documented because experiments often fail to disentangle any beneficial effects of shear stress from those delivered by convective transport of vital nutrients. We observed the development of biofilms with lognormally distributed microcolony sizes in drinking water on the walls of flow channels underflow regimes of increasing complexity. First, where regular vortices induced oscillating wall shear and simultaneously enhanced mass transport, which produced the thickest most extensive biofilms. Second, where unsteady uniform flow imposed an oscillating wall shear, with no enhanced transport, and where the biomass and coverage were only 20% smaller. Finally, for uniform steady flows with constant wall shear where the extent, thickness, and density of the biofilms were on average 60% smaller. Thus, the dynamics of shear stress played a significant role in promoting biofilm development, over and above its magnitude or mass transfer effects, and therefore, mechanosensing may prevail in complex multispecies biofilms which could open up new ways of controlling biofilm structure.}, } @article {pmid35487006, year = {2022}, author = {Pan, T and Chen, H and Gao, X and Wu, Z and Ye, Y and Shen, Y}, title = {Engineering efficient artificial nanozyme based on chitosan grafted Fe-doped-carbon dots for bacteria biofilm eradication.}, journal = {Journal of hazardous materials}, volume = {435}, number = {}, pages = {128996}, doi = {10.1016/j.jhazmat.2022.128996}, pmid = {35487006}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Carbon ; *Chitosan/pharmacology ; Hydrogen Peroxide/pharmacology ; Peroxidases ; Pseudomonas aeruginosa ; Staphylococcus aureus/physiology ; }, abstract = {Bacterial biofilms have evoked worldwide attention owing to their serious threats to public health, but how to effectively eliminate bacterial biofilms still remains great challenges. Here, we rationally designed a novel and vigorous chitosan grafted Fe-doped-carbon dots (CS@Fe/CDs) as an efficient artificial nanozyme to combat rigid bacterial biofilms through the selective activation of Fenton-like reaction-triggered peroxidase-like catalytic activity and the synergistic antibacterial activity of CS. On the one hand, the peroxidase-like catalytic activity made CS@Fe/CDs catalyze H2O2 for producing hydroxyl radicals (•OH), resulting in efficient cleavage of extracellular DNA (eDNA). On the other hand, CS was capable of binding with the negatively charged cell membrane through electrostatic interaction, changing the cell membrane permeability and causing cell death within bacterial biofilms. Based on their synergistic effects, the fragments of bacterial biofilm and exposed bacteria were persistently eradicated. Remarkably, CS@Fe/CDs-based nanozyme not only enabled the effective destroying of gram-positive Staphylococcus aureus (S. aureus) biofilms, but also completely eliminated gram-negative Pseudomonas aeruginosa (P. aeruginosa) biofilms, showing great potential as a promising anti-biofilm agent against bacteria biofilms. This proposed synergistic strategy for bacterial biofilm eradication might offer a powerful modality to manage of bacterial biofilm fouling in food safety and environmental protection.}, } @article {pmid35486299, year = {2022}, author = {Alviz-Gazitua, P and González, A and Lee, MR and Aranda, CP}, title = {Molecular Relationships in Biofilm Formation and the Biosynthesis of Exoproducts in Pseudoalteromonas spp.}, journal = {Marine biotechnology (New York, N.Y.)}, volume = {24}, number = {3}, pages = {431-447}, pmid = {35486299}, issn = {1436-2236}, support = {ID20I10127//Fondo de Fomento al Desarrollo Científico y Tecnológico/ ; }, mesh = {Biofilms ; *Pseudoalteromonas/genetics ; }, abstract = {Most members of the Pseudoalteromonas genus have been isolated from living surfaces as members of epiphytic and epizooic microbiomes on marine macroorganisms. Commonly Pseudoalteromonas isolates are reported as a source of bioactive exoproducts, i.e., secondary metabolites, such as exopolymeric substances and extracellular enzymes. The experimental conditions for the production of these agents are commonly associated with sessile metabolic states such as biofilms or liquid cultures in the stationary growth phase. Despite this, the molecular mechanisms that connect biofilm formation and the biosynthesis of exoproducts in Pseudoalteromonas isolates have rarely been mentioned in the literature. This review compiles empirical evidence about exoproduct biosynthesis conditions and molecular mechanisms that regulate sessile metabolic states in Pseudoalteromonas species, to provide a comprehensive perspective on the regulatory convergences that generate the recurrent coexistence of both phenomena in this bacterial genus. This synthesis aims to provide perspectives on the extent of this phenomenon for the optimization of bioprospection studies and biotechnology processes based on these bacteria.}, } @article {pmid35483462, year = {2022}, author = {Zhou, L and Lai, Y and Zeng, R and Zhao, B and Jian, Y and Ou, P and Zhang, W and Ng, HY and Zhuang, WQ}, title = {Core carbon fixation pathways associated with cake layer development in an anoxic-oxic biofilm-membrane bioreactor treating textile wastewater.}, journal = {The Science of the total environment}, volume = {835}, number = {}, pages = {155483}, doi = {10.1016/j.scitotenv.2022.155483}, pmid = {35483462}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; *Bioreactors ; Carbon Cycle ; Membranes, Artificial ; Sulfur ; Textiles ; *Wastewater ; }, abstract = {Microbial carbon fixation pathways have not yet been adequately understood for their role in membrane case layer formation processes. Carbon fixation bacteria can play critical roles in either causing or enhancing cake layer formation in some autotrophic-prone anoxic conditions, such as sulfur-cycling conditions. Understanding the microbes capable of carbon fixation can potentially guide the design of membrane biofouling mitigation strategies in scientific ways. Thus, we used meta-omics methods to query carbon fixation pathways in the cake layers of a full-scale anoxic-oxic biofilm-MBR system treating textile wastewater in this study. Based on the wastewater constituents and other properties, such as anoxic conditions, sulfide-reducing and sulfur-oxidizing bacteria could co-exist in the membrane unit. In addition, low-light radiation conditions could also happen to the membrane unit. However, we could not quantify the light intensity or total energy input accurately because the whole experimental setup was a full-scale system. Potentially complete carbon fixation pathways in the cake layer included the Calvin-Benson-Bassham cycle, Wood-Ljungdahl pathway, and the 3-hydroxypropionate bicycle. We discovered that using aeration could effectively inhibit carbon fixation, which resulted in mitigating membrane cake layer development. However, the aeration resulted in the 3-hydroxypropionate bicycle pathway, presumably used by aerobic sulfur-oxidizing prokaryotes, to become a more abundant carbon fixation pathway in the cake layer under aerobic conditions.}, } @article {pmid35483311, year = {2022}, author = {Law, SKK and Tan, HS}, title = {The role of quorum sensing, biofilm formation, and iron acquisition as key virulence mechanisms in Acinetobacter baumannii and the corresponding anti-virulence strategies.}, journal = {Microbiological research}, volume = {260}, number = {}, pages = {127032}, doi = {10.1016/j.micres.2022.127032}, pmid = {35483311}, issn = {1618-0623}, mesh = {*Acinetobacter Infections/drug therapy/microbiology ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Iron ; Quorum Sensing ; Virulence ; Virulence Factors ; }, abstract = {Acinetobacter baumannii is a nosocomial pathogen responsible for several serious infections, including pneumonia, sepsis, and meningitis. The propensity of this bacterium to rapidly acquire antibiotic resistance leads to the emergence and spread of multidrug-resistant A. baumannii strains. As a result, antibiotics are becoming less effective in treating infections caused by this pathogen. In recent years, increasing efforts have focused on developing therapeutic compounds that could reduce the ability of A. baumannii to establish infection by inhibiting the virulence factors and pathogenesis of this pathogen without interfering with the bacterial viability. These alternative therapeutic options may impose milder selective pressure, reducing the likelihood of anti-virulence resistance development. To develop novel anti-virulence therapies, an in-depth understanding of the bacterial virulence mechanisms is crucial to identifying potential drug targets. This review summarises the latest discoveries about the virulence of A. baumannii, focusing on quorum sensing, biofilm formation, and iron acquisition, along with the corresponding anti-virulence strategies. This article also elaborates on the practical challenges involved in developing anti-virulence drugs. Therapeutic agents that target bacterial virulence factors may play a crucial role in controlling infection in the human host. Combining anti-virulence agents with existing antibiotics could enhance the therapeutic potential of these antibiotics against A. baumannii. Although anti-virulence therapy has been envisioned as an attractive alternative to overcome antimicrobial resistance, additional research on the possibility of developing resistance against anti-virulence drugs is encouraged to evaluate the sustainability of these strategies. Moreover, future studies on the efficacy of anti-virulence therapy against a diverse panel of clinical isolates and in polymicrobial A. baumannii infections are required to provide more valuable information about its clinical application.}, } @article {pmid35481976, year = {2021}, author = {Kiran, GS and Priyadharshini, S and Anitha, K and Gnanamani, E and Selvin, J}, title = {Correction: Characterization of an exopolysaccharide from probiont Enterobacter faecalis MSI12 and its effect on the disruption of Candida albicans biofilm.}, journal = {RSC advances}, volume = {11}, number = {33}, pages = {20003-20005}, doi = {10.1039/d1ra90123k}, pmid = {35481976}, issn = {2046-2069}, abstract = {[This corrects the article DOI: 10.1039/C5RA10302A.].}, } @article {pmid35481543, year = {2022}, author = {Kulshrestha, A and Gupta, P}, title = {Polymicrobial interaction in biofilm: mechanistic insights.}, journal = {Pathogens and disease}, volume = {80}, number = {1}, pages = {}, doi = {10.1093/femspd/ftac010}, pmid = {35481543}, issn = {2049-632X}, mesh = {Anti-Bacterial Agents ; *Bacterial Infections ; Biofilms ; *Cystic Fibrosis/microbiology ; *Dental Caries ; Humans ; }, abstract = {Polymicrobial biofilm (PMBF) formation during multispecies infection is a serious threat growing worldwide. According to CDC, microbial biofilm infection covers more than 65% of total infection. In many diseases, their natural habitat does not have one causative agent because most of the species exist in coaggregation (such as in cystic fibrosis, otitis media, and dental caries) leading to PMBF. PMBF is a big problem in bacterio-fungal and interspecies bacterial diseases that developed during chronic illness and created a major health burden globally. This review focused on various aspects of PMBFs such as why they are forming PMBF arrangements, the significance of studying these biofilms, and the interaction between causative microbes. Also, we reviewed how these interactions and polymicrobial formations make biofilms more recalcitrant toward treatment. Understanding the mechanistic process behind these biofilm formations gives an insight into specific molecules, proteins responsible for their polymicrobial nature, which is likely to be very helpful in antimicrobial research.}, } @article {pmid35480673, year = {2021}, author = {Hou, Y and Liu, M and Tan, X and Hou, S and Yang, P}, title = {Study on COD and nitrogen removal efficiency of domestic sewage by hybrid carrier biofilm reactor.}, journal = {RSC advances}, volume = {11}, number = {44}, pages = {27322-27332}, pmid = {35480673}, issn = {2046-2069}, abstract = {A moving bed biofilm reactor (MBBR) is a kind of commonly used biological sewage treatment process. A carrier, the core of MBBR, could directly affect the treatment efficiency of MBBR. In this experiment, a hybrid carrier composed of an MBBR carrier and fluidized bed porous carrier was innovatively utilized to treat low-concentration simulated domestic sewage through an MBBR reactor to investigate the effects of different hydraulic retention times (HRT) and different carrier dose ratios on the reactor performance. The results indicated that when the volume ratio of the carrier dosage was 5% : 20% when the reactor HRT was 5 h, the removal rates of ammonia nitrogen, total nitrogen (TN) and chemical oxygen demand (CODCr) were optimal, which were 96.5%, 60.9% and 91.5%, respectively. The ammonia nitrogen, total nitrogen and CODCr concentrations of the effluent were 1.04 mg L[-1], 12.20 mg L[-1] and 29.02 mg L[-1], respectively. Furthermore, the total biomass concentration in the hybrid carrier biofilm reactor (HCBR) was 3790.35 mg L[-1], which also reached the highest value. As the experiment progressed, the concentrations of protein, polysaccharide and soluble microbial products (SMP) were reduced to 7.68 mg L[-1], 11.10 mg L[-1] and 18.08 mg L[-1], respectively. This was basically consistent with the results of the three-dimensional fluorescence spectrum. The results showed that the combined-carrier biofilm reactor could reduce the volumetric filling rate, improving the removal capability of organic matter and the denitrification efficiency. This study provided technical support for the composite carrier biofilm wastewater treatment technology, and also had a good prospect of application.}, } @article {pmid35480051, year = {2022}, author = {Zhang, L and Shen, Y and Qiu, L and Yu, F and Hu, X and Wang, M and Sun, Y and Pan, Y and Zhang, K}, title = {The suppression effect of SCH-79797 on Streptococcus mutans biofilm formation.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {2061113}, pmid = {35480051}, issn = {2000-2297}, abstract = {BACKGROUND: SCH-79797 was recently shown to be a broad-spectrum antibacterial agent with a dual-bactericidal mechanism. However, its anti-biofilm effect remains unknown.

PURPOSE: To investigate the effect of SCH-79797 on the biofilm formation of the cariogenic Streptococcus mutans.

METHODS AND RESULTS: Crystal violet staining, colony forming units count and MTT assays (for cell metabolic activity) revealed that S. mutans biofilm formation was significantly suppressed. In addition, virulence factors, including extracellular polysaccharides (investigated by bacterial/exopolysaccharide staining and the anthrone method) and acid production (investigated by lactic acid and supernatant pH detection) were also inhibited significantly. Moreover, the biofilm inhibitory effect of SCH-79797 was mediated through its repression of bacterial growth and not by a bactericidal effect, which was verified by growth curve and bacterial live/ dead staining, respectively. Quantitative real-time PCR results disclosed that SCH-79797 affected bacterial acid production and tolerance, polysaccharide synthesis and remodeling, biofilm formation and quorum sensing-related gene expression. In addition, SCH-79797 showed good biocompatibility as determined by cytotoxicity assays.

CONCLUSION: SCH-79797 had an anti-biofilm effect and showed application prospects in the control of dental caries.}, } @article {pmid35479755, year = {2022}, author = {Ghosh, S and Nag, M and Lahiri, D and Sarkar, T and Pati, S and Kari, ZA and Nirmal, NP and Edinur, HA and Ray, RR}, title = {Engineered Biofilm: Innovative Nextgen Strategy for Quality Enhancement of Fermented Foods.}, journal = {Frontiers in nutrition}, volume = {9}, number = {}, pages = {808630}, pmid = {35479755}, issn = {2296-861X}, abstract = {Microbial communities within fermented food (beers, wines, distillates, meats, fishes, cheeses, breads) products remain within biofilm and are embedded in a complex extracellular polymeric matrix that provides favorable growth conditions to the indwelling species. Biofilm acts as the best ecological niche for the residing microbes by providing food ingredients that interact with the fermenting microorganisms' metabolites to boost their growth. This leads to the alterations in the biochemical and nutritional quality of the fermented food ingredients compared to the initial ingredients in terms of antioxidants, peptides, organoleptic and probiotic properties, and antimicrobial activity. Microbes within the biofilm have altered genetic expression that may lead to novel biochemical pathways influencing their chemical and organoleptic properties related to consumer acceptability. Although microbial biofilms have always been linked to pathogenicity owing to its enhanced antimicrobial resistance, biofilm could be favorable for the production of amino acids like l-proline and L-threonine by engineered bacteria. The unique characteristics of many traditional fermented foods are attributed by the biofilm formed by lactic acid bacteria and yeast and often, multispecies biofilm can be successfully used for repeated-batch fermentation. The present review will shed light on current research related to the role of biofilm in the fermentation process with special reference to the recent applications of NGS/WGS/omics for the improved biofilm forming ability of the genetically engineered and biotechnologically modified microorganisms to bring about the amelioration of the quality of fermented food.}, } @article {pmid35479228, year = {2021}, author = {Cortés, I and Cordisco, E and Kaufman, TS and Sortino, MA and Svetaz, LA and Bracca, ABJ}, title = {First total synthesis of chromanone A, preparation of related compounds and evaluation of their antifungal activity against Candida albicans, a biofilm forming agent.}, journal = {RSC advances}, volume = {11}, number = {32}, pages = {19587-19597}, pmid = {35479228}, issn = {2046-2069}, abstract = {A straightforward and convenient approach for the first total syntheses of chromanone A and a related 7-OMe substituted natural product is reported. These unique C-3 substituted 2-hydroxymethyl chromones were recently isolated as fungal metabolites. Chromanone A was synthesized in 25.3% overall yield from the readily available pyrocatechol, whereas the second natural product was prepared in 39.7% global yield. A small library of chromones, including both natural products and some of their synthetic heterocyclic precursors, was evaluated against Candida albicans ATCC 10231, a biofilm forming agent. It was found that 8-methoxy-3-methyl-4-oxo-4H-chromene-2-carbaldehyde, a partially oxidized form of chromanone A, exhibited a minimum inhibitory concentration of 7.8 μg mL[-1] and significantly inhibited the yeast's virulence factors, including the adherence to buccal epithelial cells and the secretion of phospholipases, as well as the formation of germ tubes and the generation of the hyphal pseudomycelium. In addition, despite the heterocycle exhibiting non-significant inhibition of the formation of the Candida biofilm, it completely inhibited the growth of C. albicans in preformed biofilms at 62.5 μg mL[-1].}, } @article {pmid35479152, year = {2021}, author = {O'Reilly, C and Blasco, S and Parekh, B and Collins, H and Cooke, G and Gunnlaugsson, T and Byrne, JP}, title = {Ruthenium-centred btp glycoclusters as inhibitors for Pseudomonas aeruginosa biofilm formation.}, journal = {RSC advances}, volume = {11}, number = {27}, pages = {16318-16325}, pmid = {35479152}, issn = {2046-2069}, abstract = {Carbohydrate-decorated clusters (glycoclusters) centred on a Ru(ii) ion were synthesised and tested for their activity against Pseudomonas aeruginosa biofilm formation. These clusters were designed by conjugating a range of carbohydrate motifs (galactose, glucose, mannose and lactose, as well as galactose with a triethylene glycol spacer) to a btp (2,6-bis(1,2,3-triazol-4-yl)pyridine) scaffold. This scaffold, which possesses a C 2 symmetry, is an excellent ligand for d-metal ions, and thus the formation of the Ru(ii)-centred glycoclusters 7 and 8Gal was achieved from 5 and 6Gal; each possessing four deprotected carbohydrates. Glycocluster 8Gal, which has a flexible spacer between the btp and galactose moieties, showed significant inhibition of P. aeruginosa bacterial biofilm formation. By contrast, glycocluster 7, which lacked the flexible linker, didn't show significant antimicrobial effects and neither does the ligand 6Gal alone. These results are proposed to arise from carbohydrate-lectin interactions with LecA, which are possible for the flexible metal-centred multivalent glycocluster. Metal-centred glycoclusters present a structurally versatile class of antimicrobial agent for P. aeruginosa, of which this is, to the best of our knowledge, the first example.}, } @article {pmid35477339, year = {2022}, author = {Ceccarelli, F and Saccucci, M and Natalucci, F and Olivieri, G and Bruni, E and Iacono, R and Colasanti, T and Di Carlo, G and Alessandri, C and Uccelletti, D and Russo, P and Pilloni, A and Conti, F and Polimeni, A}, title = {Porphyromonas gingivalis amount in the tongue biofilm is associated with erosive arthritis in systemic lupus erythematosus.}, journal = {Lupus}, volume = {31}, number = {8}, pages = {921-926}, doi = {10.1177/09612033221098528}, pmid = {35477339}, issn = {1477-0962}, mesh = {*Arthritis, Rheumatoid ; Autoantibodies ; Biofilms ; Humans ; *Lupus Erythematosus, Systemic ; Porphyromonas gingivalis ; Tongue/pathology ; }, abstract = {BACKGROUND: Several data have demonstrated the occurrence of erosive arthritis in Systemic Lupus Erythematosus (SLE) patients. However, a few studies have focused on the pathogenic mechanisms involved in this feature. The implication of oral pathogens has been proved in Rheumatoid Arthritis: in particular, Porphyromonas gingivalis (Pg), by inducing citrullination, could trigger autoimmune response. Here, we evaluated amount of Pg on the tongue in a cohort of SLE patients with arthritis, focusing on the association with the erosive phenotype.

METHODS: SLE patients with arthritis were enrolled. DAS28 was applied to assess activity. Erosive damage was evaluated by ultrasound at level of MCP (metacarpophalangeal) and PIP (proximal interphalangeals) joints. All subjects underwent a tongue cytologic swab in order to quantify the amount of Pg (real-time PCR). The bacterium expression was obtained from the ratio between the patient's DNA amount and that obtained from healthy subjects.

RESULTS: 33 patients were enrolled (M/F 3/30; median age 47 years, IQR 17; median disease duration 216 months, IQR 180): 12 of them (36.4%) showed erosive damage, significantly associated with ACPA positivity (p = 0.03) and higher values of DAS28 (p = 0.01). A mean ratio of 19.7 ± 31.1 was found for Pg amount. Therefore, we used Pg mean values as threshold, identifying two groups of patients, namely, highPg and lowPg. Erosive damage was significantly more frequent in highPg patients in comparison with lowPg (60.0% vs 26.0%, p = 0.001). Furthermore, highPg patients showed higher prevalence of skin manifestations, serositis, and neurological involvement (p = 0.005, p = 0.03, p = 0.0001, respectively).

CONCLUSION: The possible contribution of oral microbiota in SLE erosive arthritis was here evaluated for the first time, finding a significant association between erosive damage and higher expression of Pg at tongue level.}, } @article {pmid35477070, year = {2022}, author = {de Oliveira Pinto Ribeiro, A and Carolina da Silva, A and de Camargo Ribeiro, F and Sabino, CF and Junqueira, JC and de Paula Ramos, L and Dias de Oliveira, L and Bastos Campos, TM and Marques de Melo Marinho, R}, title = {Biofilm formation and cell viability on monolithic zirconia with silver-doped sodalime glass.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {131}, number = {}, pages = {105222}, doi = {10.1016/j.jmbbm.2022.105222}, pmid = {35477070}, issn = {1878-0180}, mesh = {Biofilms ; Candida albicans ; Cell Survival ; Materials Testing ; *Silver/pharmacology ; Surface Properties ; *Zirconium/chemistry ; }, abstract = {The present study evaluated the effect of glass application with and without silver-doped soda-lime glass on roughness, biofilm formation, cell viability and flexural strength of a zirconia. Samples of 3-YTZP (3 mol% yttria stabilized tetragonal zirconia polycrystals) were divided into: polished (P); glaze (G); glass infiltration (INF); 4% silver-doped soda-lime glass (Ag4); glass infiltration + 4% silver-doped soda-lime glass (INF-Ag4); 5% silver-doped soda-lime glass (Ag5); glass infiltration + 5% silver-doped soda-lime glass (INF-Ag5). Samples were submitted to the following analyses: roughness (Ra); free surface energy (FSE); colony-forming units count (log CFU/mL); scanning electron microscopy (SEM); cytotoxicity (MTT assay) and flexural strength. Ag5 had greater roughness and FSE, but less biofilm adherence. In the CFU, silver-doped soda-lime glass groups inhibited the growth of Candida albicans, while the Ag5 inhibited Streptococcus mutans and none of the groups was effective against Streptococcus sanguinis. In the qualitative evaluation, lower number of colonies in the Ag5 grew up, compared to the control groups (P; G and INF) for both C. albicans and S. mutans. Regarding the MTT assay, the Ag4, INF-Ag4 and INF-Ag5 obtained percentage of cell viability greater than 50%. Ag5 showed lower flexural strength when compared to the control groups, while the application of glass infiltration increased the flexural strength by formation of a graded region between zirconia-glass. In conclusion, Ag5 had the greatest antimicrobial effect, Ag4 and INF-Ag4 were the less cytotoxic and the INF was the most resistant to fracture. Therefore, INF-Ag4 conciliates the best performance in terms of antimicrobial and mechanical properties for a 3-YTZP.}, } @article {pmid35476392, year = {2022}, author = {Dang, J and Zhu, M and Dong, F and Zhong, R and Liu, Z and Fang, J and Zhang, J and Pan, J}, title = {Ultrasound-Activated Nanodroplet Disruption of the Enterococcus faecalis Biofilm in Dental Root Canal.}, journal = {ACS applied bio materials}, volume = {5}, number = {5}, pages = {2135-2142}, doi = {10.1021/acsabm.1c01031}, pmid = {35476392}, issn = {2576-6422}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Chlorhexidine/pharmacology ; Dental Pulp Cavity ; *Enterococcus faecalis ; Humans ; *Root Canal Irrigants/pharmacology ; }, abstract = {Conventional methods used to control bacterial biofilm infection in root canals have poor efficacy, causing repeated and chronic infections, which pose a great challenge to clinical treatment. Microbubbles, due to their small size and ultrasound (US)-enhanced cavitation effects, have attracted considerable clinical attention. They possess the potential for therapeutic application in restricted spaces. We address the above problem with a strategy for the restricted space of root canals. Herein, phase-change nanodroplets (P-NDs) exposed to US are combined with common antibacterial drugs to disrupt a 7 day Enterococcus faecalis biofilm in an in vitro human tooth model. Specifically, the preparation of P-NDs is based on secondary cavitation. Their average particle size is ∼144 nm, and the stability is favorable. The clearance effect for the biofilm is notable (the disruption rate of P-NDs + US is 63.1%, P < 0.01), while the effect of an antibacterial in conjunction with 2% chlorhexidine (Chx) is significant (the antibiofilm rate of P-NDs@2% Chx + US is 96.2%, P < 0.001). Furthermore, biocompatibility testing on human periodontal ligament fibroblasts demonstrated that P-NDs are safe. In summary, the strategy that we have proposed is suitable for the removal of biofilms in root canals. Notably, it also has great potential for application in the treatment of bacterial infections in restricted spaces.}, } @article {pmid35475640, year = {2022}, author = {Trampari, E and Zhang, C and Gotts, K and Savva, GM and Bavro, VN and Webber, M}, title = {Cefotaxime Exposure Selects Mutations within the CA-Domain of envZ Which Promote Antibiotic Resistance but Repress Biofilm Formation in Salmonella.}, journal = {Microbiology spectrum}, volume = {10}, number = {3}, pages = {e0214521}, pmid = {35475640}, issn = {2165-0497}, support = {MR/L015080/1/MRC_/Medical Research Council/United Kingdom ; BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/CCG1860/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacterial Outer Membrane Proteins/metabolism ; Biofilms ; *Cefotaxime/pharmacology ; Drug Resistance, Microbial ; Mutation ; Porins/genetics ; Salmonella ; }, abstract = {Cephalosporins are important beta lactam antibiotics, but resistance can be mediated by various mechanisms including production of beta lactamase enzymes, changes in membrane permeability or active efflux. We used an evolution model to study how Salmonella adapts to subinhibitory concentrations of cefotaxime in planktonic and biofilm conditions and characterized the mechanisms underpinning this adaptation. We found that Salmonella rapidly adapts to subinhibitory concentrations of cefotaxime via selection of multiple mutations within the CA-domain region of EnvZ. We showed that changes in this domain affect the ATPase activity of the enzyme and in turn impact OmpC, OmpF porin expression and hence membrane permeability leading to increased tolerance to cefotaxime and low-level resistance to different classes of antibiotics. Adaptation to cefotaxime through EnvZ also resulted in a significant cost to biofilm formation due to downregulation of curli. We assessed the role of the mutations identified on the activity of EnvZ by genetic characterization, biochemistry and in silico analysis and confirmed that they are responsible for the observed phenotypes. We observed that sublethal cefotaxime exposure selected for heterogeneity in populations with only a subpopulation carrying mutations within EnvZ and being resistant to cefotaxime. Population structure and composition dynamically changed depending on the presence of the selection pressure, once selected, resistant subpopulations were maintained even in extended passage without drug. IMPORTANCE Understanding mechanisms of antibiotic resistance is crucial to guide how best to use antibiotics to minimize emergence of resistance. We used a laboratory evolution system to study how Salmonella responds to cefotaxime in both planktonic and biofilm conditions. In both contexts, we observed rapid selection of mutants within a single hot spot within envZ. The mutations selected altered EnvZ which in turn triggers changes in porin production at the outer membrane. Emergence of mutations within this region was repeatedly observed in parallel lineages in different conditions. We used a combination of genetics, biochemistry, phenotyping and structural analysis to understand the mechanisms. This data show that the changes we observe provide resistance to cefotaxime but come at a cost to biofilm formation and the fitness of mutants changes greatly depending on the presence or absence of a selective drug. Studying how resistance emerges can inform selective outcomes in the real world.}, } @article {pmid35474246, year = {2022}, author = {Sun, M and Chan, KF and Zhang, Z and Wang, L and Wang, Q and Yang, S and Chan, SM and Chiu, PWY and Sung, JJY and Zhang, L}, title = {Magnetic Microswarm and Fluoroscopy-Guided Platform for Biofilm Eradication in Biliary Stents.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {34}, number = {34}, pages = {e2201888}, doi = {10.1002/adma.202201888}, pmid = {35474246}, issn = {1521-4095}, support = {E-CUHK401/20//Hong Kong Research Grants Council (RGC)/ ; GRF14300621//Hong Kong Research Grants Council (RGC)/ ; MRP/036/18X//HKSAR Innovation and Technology Commission (ITC)/ ; CAS20403//Croucher Foundation Grant/ ; //CUHK internal grants/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacterial Infections/drug therapy ; *Biofilms ; Fluoroscopy ; Humans ; Magnetic Phenomena ; Stents/microbiology ; }, abstract = {Biofilm eradication from medical implants is of fundamental importance, and the treatment of biofilm-associated pathogen infections on inaccessible biliary stents remains challenging. Magnetically driven microrobots with controlled motility, accessibility to the tiny lumen, and swarm enhancement effects can physically disrupt the deleterious biostructures while not developing drug resistance. Magnetic urchin-like capsule robots (MUCRs) loaded with magnetic liquid metal droplets (MLMDs, antibacterial agents) are designed using natural sunflower pollen, and the therapeutic effect of swarming MUCR@MLMDs is explored for eradicating complex mixtures of bacterial biofilm within biliary stents collected from patients. The external magnetic field triggers the emergence of the microswarm and induces MLMDs to transform their shape into spheroids and rods with sharp edges. The inherent natural microspikes of MUCRs and the obtained sharp edges of MLMDs actively rupture the dense biological matrix and multiple species of embedded bacterial cells by exerting mechanical force, finally achieving synergistic biofilm eradication. The microswarm is precisely and rapidly deployed into the biliary stent via endoscopy in 10 min. Notably, fluoroscopy imaging is used to track and navigate the locomotion of microswarm in biliary stents in real-time. The microswarm has great potential for treating bacterial biofilm infections associated with medical implants.}, } @article {pmid35473968, year = {2022}, author = {Sun, Y and Ma, Y and Guan, H and Liang, H and Zhao, X and Wang, D}, title = {Adhesion mechanism and biofilm formation of Escherichia coli O157:H7 in infected cucumber (Cucumis sativus L.).}, journal = {Food microbiology}, volume = {105}, number = {}, pages = {103885}, doi = {10.1016/j.fm.2021.103885}, pmid = {35473968}, issn = {1095-9998}, mesh = {Biofilms ; *Cucumis sativus/metabolism ; *Escherichia coli O157 ; *Escherichia coli Proteins/genetics ; Fruit/metabolism ; }, abstract = {Cucumber is usually eaten as a raw vegetable and easily contaminated by pathogenic microorganisms; the contamination process includes colonization, proliferation, and biofilm formation. In this study, plate counting was used to determine the stage of E. coli O157:H7 colonization/proliferation in cucumber epidermis and fruit. Expression of E. coli genes associated with adhesion, movement and oxidative stress response during colonization and proliferation in cucumber was evaluated with fluorescence real-time quantitative PCR. Scanning electron microscopy imaging was used to observe biofilm formation over time in different cucumber tissues at 4 °C and 25 °C. During colonization (at 0-45 and 0-30 min in epidermis and fruit, respectively), escV, fliC, espA, escN, espF, espG, espZ, nleA, tir, and ycbR genes were upregulated. The escC was downregulated, while map and espH expression did not vary. During proliferation (after 45 and 30 min in epidermis and fruit, respectively), fliC was downregulated, whereas the outer membrane protein intimin gene and oxidative stress genes rpoS and sodB were upregulated. During storage, 25 °C was more favorable for biofilm formation than 4 °C. The ability of biofilm formation on the vascular system was the strongest, and the biofilm on epidermis sloughed off earlier than that on other tissues. Clarifying the process of E. coli O157:H7 contaminating cucumbers provided useful information for the development of prevention and control methods of fresh-cut cucumber.}, } @article {pmid35470982, year = {2022}, author = {Secker, TJ and Harling, CC and Hand, C and Voegeli, D and Keevil, CW and Leighton, TG}, title = {A proof-of-concept study of the removal of early and late phase biofilm from skin wound models using a liquid acoustic stream.}, journal = {International wound journal}, volume = {19}, number = {8}, pages = {2124-2135}, pmid = {35470982}, issn = {1742-481X}, support = {EP/M027260/1//NAMRIP Pump priming supported by EPSRC/ ; }, mesh = {Swine ; Animals ; Humans ; *Wound Infection/drug therapy ; Biofilms ; Pseudomonas aeruginosa ; *Soft Tissue Injuries/microbiology ; Acoustics ; }, abstract = {Chronic wounds fail to progress through the normal stages of healing, with the largest remediable cause of chronicity being presence of a multi-species biofilm. Removal of biofilm from the wound environment is central to wound care. A device for mechanically removing biofilms from wounds has been devised. The removal is caused by small-scale liquid currents and shear, generated by acoustically activated microscopic air bubbles. These bubbles and acoustic waves are delivered onto the wound by a gentle liquid stream, allowing cleaning in situ and removal of debris in the run-off liquid. We have investigated if this liquid acoustic wound stream (LAWS) can remove bacterial biofilm from soft biological wound models and studied the effect of LAWS on the cellular tissues of the substrate. LAWS will efficiently remove early Pseudomonas aeruginosa biofilm from an artificial wound in a pig's trotter, 24 hours-mature biofilm of P. aeruginosa from a pre-wounded human full thickness skin model (EpiDerm FT), and 3-day mature biofilm of P. aeruginosa or Staphylococcus aureus from a porcine skin explant. Histological examinations of uninfected EpiDerm models that had been treated by LAWS and then stained with Haematoxylin and Eosin, demonstrated no damage to the human tissue, and wound diameter was smaller in the treated skin models compared with untreated samples. Immunofluorescence staining for cytokeratin 14 showed that keratinocytes had migrated further across the wound in the uninfected samples treated by LAWS. We discuss the implications for wound healing and propose further laboratory and clinical studies to demonstrate the removal of biofilm from patients with chronic leg ulcers and the impact on healing.}, } @article {pmid35470896, year = {2022}, author = {Zhang, YM and Jiang, YH and Li, HW and Li, XZ and Zhang, QL}, title = {Purification and characterization of Lactobacillus plantarum-derived bacteriocin with activity against Staphylococcus argenteus planktonic cells and biofilm.}, journal = {Journal of food science}, volume = {87}, number = {6}, pages = {2718-2731}, doi = {10.1111/1750-3841.16148}, pmid = {35470896}, issn = {1750-3841}, support = {202101BE070001-046//Applied Basic Research Foundation of Yunnan Province/ ; 2021-SF-A4//Major Science and Technology Projects of Qinghai Province/ ; 2019-ZJ-967Q//Natural Science Foundation of Qinghai Province/ ; }, mesh = {Anti-Bacterial Agents/chemistry ; *Bacteriocins/chemistry ; Biofilms ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; *Lactobacillus plantarum/chemistry ; Staphylococcus ; }, abstract = {Bacteriocins inhibit various foodborne bacteria in planktonic and biofilm forms. However, bacteriocins with antibacterial and antibiofilm activity against Staphylococcus argenteus, a pathogen that can cause food poisoning, are still poorly known. Here, the novel bacteriocin LSB1 derived from Lactobacillus plantarum CGMCC 1.12934 was purified and characterized extensively. LSB1 had a molecular weight of 1425.78 Da and an amino acid sequence of YIFVTGGVVSSLGK. Moreover, LSB1 exhibited excellent stability under heat and acid-base stress and presented sensitivity to pepsin and proteinase K. LSB1 exhibited an extensive antimicrobial spectrum against both Gram-positive and Gram-negative bacteria. Minimum inhibitory concentration of LSB1 against S. argenteus_70917 was 10.36 µg/ml, which was lower than that of most of the previously found bacteriocins against Staphylococcus strains. Furthermore, LSB1 significantly inhibited S. argenteus_70917 planktonic cells (p < 0.01) and decreased their viability. Scanning electron microscopy analysis revealed that cell membrane permeability of S. argenteus_70917 upon exposure to LSB1 showed leakage of cytoplasmic contents and rupture, leading to cell death. In addition, biofilm formation ability of S. argenteus_70917 was significantly (p < 0.01) impaired by LSB1, with the percent inhibition of 35% at 10 µg/ml and 80% at 20 µg/ml. Overall, this study indicates that LSB1 can be considered a potential antibacterial agent in the control of S. argenteus in both planktonic and biofilm states. PRACTICAL APPLICATION: Foodborne pathogenic bacteria, such as Staphylococcus argenteus, and their biofilms represent potential risks for food safety. In recent years, customers' demand for "natural" products has increased food control. This study describes the novel bacteriocin LSB1 produced by the lactic acid bacterium species Lactobacillus plantarum. LSB1 showed strong antibacterial and antibiofilm activity against S. argenteus as well as thermal and acid-alkaline stability. Furthermore, the mechanisms of action of LSB1 on S. argenteus were preliminarily explored. These results indicate that LSB1 might be potentially used as an effective and natural food preservative.}, } @article {pmid35470434, year = {2022}, author = {Borges, MMB and Dijkstra, RJB and de Andrade, FB and Duarte, MAH and Versluis, M and van der Sluis, LWM and Petridis, X}, title = {The response of dual-species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: A laboratory real-time evaluation using optical coherence tomography.}, journal = {International endodontic journal}, volume = {55}, number = {7}, pages = {758-771}, pmid = {35470434}, issn = {1365-2591}, support = {88887.371170/2019-00//Capes scholarship/ ; }, mesh = {Biofilms ; *Etidronic Acid ; Humans ; *Root Canal Irrigants/pharmacology ; Sodium Hypochlorite/pharmacology ; Tomography, Optical Coherence ; }, abstract = {AIM: The addition of etidronic acid (HEDP) to sodium hypochlorite (NaOCl) could increase the antibiofilm potency of the irrigant, whilst maintaining the benefits of continuous chelation. Studies conducted so far have shown that mixing HEDP with NaOCl solutions of relatively low concentration does not compromise the antibiofilm efficacy of the irrigant. However, the working lifespan of NaOCl may decrease resulting in a reduction of its antibiofilm efficacy over time (efficiency). In this regard, continuous irrigant replenishment needs to be examined. This study investigated the response of a dual-species biofilm when challenged with 2% and 5% NaOCl mixed with HEDP for a prolonged timespan and under steady laminar flow.

METHODOLOGY: Dual-species biofilms comprised of Streptococcus oralis J22 and Actinomyces naeslundii T14V-J1 were grown on human dentine discs in a constant depth film fermenter (CDFF) for 96 h. Biofilms were treated with 2% and 5% NaOCl, alone or mixed with HEDP. Irrigants were applied under steady laminar flow for 8 min. Biofilm response was evaluated by means of optical coherence tomography (OCT). Biofilm removal, biofilm disruption, rate of biofilm loss and disruption as well as bubble formation were assessed. One-way anova, Wilcoxon's signed-rank test and Kruskal-Wallis H test were performed for statistical analysis of the data. The level of significance was set at a ≤.05.

RESULTS: Increasing NaOCl concentration resulted in increased biofilm removal and disruption, higher rate of biofilm loss and disruption and increased bubble formation. Mixing HEDP with NaOCl caused a delay in the antibiofilm action of the latter, without compromising its antibiofilm efficacy.

CONCLUSIONS: NaOCl concentration dictates the biofilm response irrespective of the presence of HEDP. The addition of HEDP resulted in a delay in the antibiofilm action of NaOCl. This delay affects the efficiency, but not the efficacy of the irrigant over time.}, } @article {pmid35469882, year = {2022}, author = {Vincent, AES and Chaudhary, A and Kelly, JJ and Hoellein, TJ}, title = {Biofilm assemblage and activity on plastic in urban streams at a continental scale: Site characteristics are more important than substrate type.}, journal = {The Science of the total environment}, volume = {835}, number = {}, pages = {155398}, doi = {10.1016/j.scitotenv.2022.155398}, pmid = {35469882}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; Chlorophyll A ; Ecosystem ; *Plastics ; Polystyrenes ; *Rivers ; }, abstract = {The fate of plastics in rivers is a key component of the global plastic cycle. Plastics entering freshwater ecosystems are colonized by microbial biofilms, and microbe-plastic interactions can influence ecosystem processes and plastic fate. While literature examining the role of geographic region on plastic biofilms is quickly expanding, research which covers large (i.e., continental) spatial scales and includes freshwater ecosystems is warranted. In addition, most research focuses on bacterial communities, while biofilm eukaryotes are less commonly studied. We assessed biofilm metabolism and community structure on plastic (foamed polystyrene and polyvinyl chloride; PVC) and natural substrates (unglazed ceramic tile) in urban streams spanning a nested geographic gradient in the continental United States. We measured biofilm biomass, community respiration, and chlorophyll a, in addition to assessing marker gene-based community diversity of bacterial, fungal, and algal assemblages. Results demonstrated some substrate-specific trends in biofilm characteristics, including higher biofilm biomass on polystyrene across sites, and lower diversity of bacterial assemblages on both types of plastic litter versus tile. However, there were no differences among substrates for chlorophyll, respiration, and the abundance and diversity of algal and fungal assemblages. Thus, we concluded that the primary driver of biofilm metabolism and community composition were site characteristics, rather than substrate type. Additional studies are needed to quantify which site-specific characteristics drive biofilm dynamics on plastic litter in streams (e.g., water chemistry, light, seasonality, hydrology). These results add to the growing literature on the biofilm 'plastisphere' in aquatic ecosystems, demonstrating that the factors which control the assembly and activity of biofilm communities on plastic substrates (including bacteria, algal, and fungal assemblages together) in urban streams are similar to those driving biofilm dynamics on natural substrates.}, } @article {pmid35469529, year = {2022}, author = {Anju, VT and Busi, S and Kumar, S and Suchiang, K and Kumavath, R and Ranganathan, S and Ampasala, DR and Dyavaiah, M}, title = {Alantolactone modulates the production of quorum sensing mediated virulence factors and biofilm formation in Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {38}, number = {4}, pages = {331-347}, doi = {10.1080/08927014.2022.2064747}, pmid = {35469529}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Caenorhabditis elegans/microbiology ; Humans ; Lactones ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Sesquiterpenes, Eudesmane ; Virulence ; Virulence Factors/metabolism ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen in immunocompromised patients and accounts for mortality worldwide. Quorum sensing (QS) and QS mediated biofilm formation of P. aeruginosa increase the severity of infection in the host. New and effective therapeutics are in high demand to eliminate Pseudomonas infections. The current study investigated the quorum quenching and biofilm inhibition properties of alantolactone (ATL) against P. aeruginosa PAO1. The production of key virulence factors and biofilm components were affected in bacteria when treated with sub-MIC of ATL and further validated by qRT-PCR studies. The anti-infective potential of ATL was corroborated in an in vivo model with improved survival of infected Caenorhabditis elegans and reduced bacterial colonization. In silico studies suggested the molecular interactions of ATL to QS proteins as stable. Finally, ATL was explored in the present study to inhibit QS pathways and holds the potential to develop into an effective anti-infective agent against P. aeruginosa.}, } @article {pmid35468355, year = {2022}, author = {Santore, MM}, title = {Interplay of physico-chemical and mechanical bacteria-surface interactions with transport processes controls early biofilm growth: A review.}, journal = {Advances in colloid and interface science}, volume = {304}, number = {}, pages = {102665}, doi = {10.1016/j.cis.2022.102665}, pmid = {35468355}, issn = {1873-3727}, mesh = {*Bacteria ; Bacterial Adhesion/physiology ; *Biofilms ; Cell Membrane ; Hydrodynamics ; }, abstract = {Biofilms initiate when bacteria encounter and are retained on surfaces. The surface orchestrates biofilm growth through direct physico-chemical and mechanical interactions with different structures on bacterial cells and, in turn, through its influence on cell-cell interactions. Individual cells respond directly to a surface through mechanical or chemical means, initiating "surface sensing" pathways that regulate gene expression, for instance producing extra cellular matrix or altering phenotypes. The surface can also physically direct the evolving colony morphology as cells divide and grow. In either case, the physico-chemistry of the surface influences cells and cell communities through mechanisms that involve additional factors. For instance the numbers of cells arriving on a surface from solution relative to the generation of new cells by division depends on adhesion and transport kinetics, affecting early colony density and composition. Separately, the forces experienced by adhering cells depend on hydrodynamics, gravity, and the relative stiffnesses and viscoelasticity of the cells and substrate materials, affecting mechanosensing pathways. Physical chemistry and surface functionality, along with interfacial mechanics also influence cell-surface friction and control colony morphology, in particular 2D and 3D shape. This review focuses on the current understanding of the mechanisms in which physico-chemical interactions, deriving from surface functionality, impact individual cells and cell community behavior through their coupling with other interfacial processes.}, } @article {pmid35467829, year = {2022}, author = {Mudenur, C and Boruah, P and Kumar, A and Katiyar, V}, title = {Prodigiosin-Loaded Poly(lactic acid) to Combat the Biofilm-Associated Infections.}, journal = {ACS applied bio materials}, volume = {5}, number = {5}, pages = {2143-2151}, doi = {10.1021/acsabm.1c01187}, pmid = {35467829}, issn = {2576-6422}, mesh = {Biofilms ; *Polyesters/chemistry ; *Prodigiosin/pharmacology ; Staphylococcus aureus ; }, abstract = {Poly(lactic acid) (PLA) is an emerging biobased implant material. Despite its biocompatibility and the aseptic procedures followed during orthopedic surgery, bacterial infection remains an obstacle to implementing PLA-based implants. To tackle this issue, prodigiosin-incorporated PLA has been developed, which possesses improved hydrophobicity with a contact angle of 111 ± 1.5°. The degradation temperature of the prodigiosin is 215 °C, which is more than the melting temperature of PLA, which supports the processability and sterilization of the PLA-based implants without any toxic gases. Further, prodigiosin improves the transparency of PLA and acts as a nucleation site. The spherulite density increases three times compared to that of neat PLA. The inherent methoxy group of prodigiosin is an active site responsible for the inhibition of bacterial attack and biofilm formation. The in vitro study on biofilm formation shows excellent inhibition activity against implant-associated pathogens such as Klebsiella aerogenes and Staphylococcus aureus.}, } @article {pmid35467419, year = {2022}, author = {Klementiev, AD and Jin, Z and Whiteley, M}, title = {Erratum for Klementiev et al., "Micron Scale Spatial Measurement of the O2 Gradient Surrounding a Bacterial Biofilm in Real Time".}, journal = {mBio}, volume = {13}, number = {3}, pages = {e0080322}, doi = {10.1128/mbio.00803-22}, pmid = {35467419}, issn = {2150-7511}, } @article {pmid35467317, year = {2022}, author = {Sharma, RP and Raut, SD and Jadhav, VV and Mulani, RM and Kadam, AS and Mane, RS}, title = {Assessment of antibacterial and anti-biofilm effects of zinc ferrite nanoparticles against Klebsiella pneumoniae.}, journal = {Folia microbiologica}, volume = {67}, number = {5}, pages = {747-755}, pmid = {35467317}, issn = {1874-9356}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology ; Bacteria/metabolism ; Biofilms ; Ferric Compounds ; Klebsiella pneumoniae ; Microbial Sensitivity Tests ; *Nanoparticles ; Reactive Oxygen Species/metabolism ; Sugars/pharmacology ; Zinc/pharmacology ; }, abstract = {In response to the emergence of drug resistance and limited therapeutic options, researchers are in action to look for more effective and sustainable antimicrobial practices. Over few years, novel nanoparticles are proving to be potent and promising for effectively dealing with ever- evolving microbial pathogens and diseases. In the present investigation, antibacterial and anti-biofilm efficiencies of zinc ferrite nanoparticles (ZnFe2O4 NPs) are explored against opportunistic pathogens Klebsiella pneumoniae (K. pneumoniae). Results of the present study demonstrate that the ZnFe2O4 NPs endow an excellent antibacterial efficiency with a maximum zone of inhibition i.e.16 mm. The reactive oxygen species (ROS)-induced bacterial damage is caused by the ZnFe2O4 NPs. Subsequently, intracellular cytoplasmic leakage of sugar and protein confirms their ability to disturb the membrane integrity of bacteria. This study also demonstrates the prominent efficiency of ZnFe2O4 NPs in an anti-biofilm study by inhibiting biofilm formation up to 81.76% and reducing mature biofilm up to 56.22% at 75 μg/mL the minimum inhibitory concentration value. Therapeutic possibilities of the ZnFe2O4 NPs in antimicrobial applications are discussed which are helpful to overcome the challenges associated with biofilm infectivity.}, } @article {pmid35466520, year = {2022}, author = {Gautam, A and Lear, G and Lewis, GD}, title = {Time after time: detecting annual patterns in stream bacterial biofilm communities.}, journal = {Environmental microbiology}, volume = {24}, number = {5}, pages = {2502-2515}, pmid = {35466520}, issn = {1462-2920}, mesh = {*Bacteria/genetics ; Biofilms ; RNA, Ribosomal, 16S/genetics ; *Rivers/microbiology ; Seasons ; }, abstract = {To quantify the major environmental drivers of stream bacterial population dynamics, we modelled temporal differences in stream bacterial communities to quantify community shifts, including those relating to cyclical seasonal variation and more sporadic bloom events. We applied Illumina MiSeq 16S rRNA bacterial gene sequencing of 892 stream biofilm samples, collected monthly for 36-months from six streams. The streams were located a maximum of 118 km apart and drained three different catchment types (forest, urban and rural land uses). We identified repeatable seasonal patterns among bacterial taxa, allowing their separation into three ecological groupings, those following linear, bloom/trough and repeated, seasonal trends. Various physicochemical parameters (light, water and air temperature, pH, dissolved oxygen, nutrients) were linked to temporal community changes. Our models indicate that bloom events and seasonal episodes modify biofilm bacterial populations, suggesting that distinct microbial taxa thrive during these events including non-cyanobacterial community members. These models could aid in determining how temporal environmental changes affect community assembly and guide the selection of appropriate statistical models to capture future community responses to environmental change.}, } @article {pmid35464993, year = {2022}, author = {Liu, S and Chen, L and Wang, L and Zhou, B and Ye, D and Zheng, X and Lin, Y and Zeng, W and Zhou, T and Ye, J}, title = {Cluster Differences in Antibiotic Resistance, Biofilm Formation, Mobility, and Virulence of Clinical Enterobacter cloacae Complex.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {814831}, pmid = {35464993}, issn = {1664-302X}, abstract = {Due to the lack of research on the characteristics of different clusters of Enterobacter cloacae complex (ECC), this study aimed to characterize and explore the differences among species of the ECC. An analysis based on hsp60 showed that Enterobacter hormaechei was predominant in ECC. Interestingly, the antibiotic resistance rates of clusters were different, among which E. hormaechei subsp. steigerwaltii (cluster VIII) and Enterobacter cloacae IX (cluster IX) possessed high resistant rates to ciprofloxacin and levofloxacin, but cluster II (Enterobacter kobei) had low resistant rates. Cluster II exhibited a strong biofilm formation ability. Different motility and protease production ability were shown for distinct clusters. A PCR analysis showed that clusters I, III, VI, VIII, and IX carried more virulence genes, while cluster II had fewer. Clusters I, VIII, and IX with high pathogenicity were evaluated using the Galleria mellonella infection model. Thus, the characteristics of resistance, biofilm-forming ability, mobility, and virulence differed among the clusters. The strains were divided into 12 subgroups based on hsp60. The main clusters of ECC clinical strains were I, II, III, VI, VIII, and IX, among which IX, VIII, and I were predominant with high resistance and pathogenicity, and cluster II (E. kobei) was a special taxon with a strong biofilm formation ability under nutrient deficiency, but was associated with low resistance, virulence, and pathogenicity. Hence, clinical classification methods to identify ECC subgroups are an urgent requirement to guide the treatment of clinical infections.}, } @article {pmid35464992, year = {2022}, author = {Pouget, C and Dunyach-Remy, C and Bernardi, T and Provot, C and Tasse, J and Sotto, A and Lavigne, JP}, title = {A Relevant Wound-Like in vitro Media to Study Bacterial Cooperation and Biofilm in Chronic Wounds.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {705479}, pmid = {35464992}, issn = {1664-302X}, abstract = {Biofilm on the skin surface of chronic wounds is an important factor in the pathology, inhibiting wound healing. The polymicrobial nature of these infected wounds and bacterial interactions inside this pathogenic biofilm are the keys for understanding chronic infection. The aim of our work was to develop an innovative in vitro medium that closely mimics the chronic wound emphasizing the microbiological, cellular, and inflammatory environment of chronic wounds but also focusing on the pH found at the wound level. This new medium, called chronic wound medium (CWM), will thus facilitate the study of pathogenic biofilm organization. Clinical Staphylococcus aureus and Pseudomonas aeruginosa strains coisolated from diabetic foot infection were collected and cultivated in this new medium for 24 h in monoculture and coculture. Bacterial growth (growth curves), presence of small colony variant (SCV), biofilm formation (BioFilm Ring Test[®] assay, biofilm biomass quantification), and virulence (survival curve in a Caenorhabditis elegans model) were evaluated. After 24 h in the in vitro conditions, we observed that P. aeruginosa growth was not affected, compared with a control bacterial medium, whereas for S. aureus, the stationary phase was reduced by two logs. Interestingly, S. aureus growth increased when cocultured with P. aeruginosa in CWM. In coculture with P. aeruginosa, SCV forms of S. aureus were detected. Biofilm studies showed that bacteria, alone and in combination, formed biofilm faster (as soon as 3 h) than the bacteria exposed in a control medium (as soon as 5 h). The virulence of all strains decreased in the nematode model when cultivated in our new in vitro medium. Taken together, our data confirmed the impact of the chronic wound environment on biofilm formation and bacteria virulence. They indicated that P. aeruginosa and S. aureus cooperated in coinfected wounds. Therefore, this in vitro model provides a new tool for bacterial cooperation investigation and polymicrobial biofilm formation.}, } @article {pmid35464966, year = {2022}, author = {Lv, J and Zhu, J and Wang, T and Xie, X and Wang, T and Zhu, Z and Chen, L and Zhong, F and Du, H}, title = {The Role of the Two-Component QseBC Signaling System in Biofilm Formation and Virulence of Hypervirulent Klebsiella pneumoniae ATCC43816.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {817494}, pmid = {35464966}, issn = {1664-302X}, abstract = {Hypervirulent Klebsiella pneumoniae (hvKP) is an evolving infectious pathogen associated with high mortality. The convergence of hypervirulence and multidrug resistance further challenges the clinical treatment options for K. pneumoniae infections. The QseBC two-component system (TCS) is a component of quorum-sensing regulatory cascade and functions as a global regulator of biofilm growth, bacterial motility, and virulence in Escherichia coli. However, the functional mechanisms of QseBC in hvKP have not been reported, and we aim to examine the role of QseBC in regulating virulence in hvKP strain ATCC43816. The CRISPR-Cas9 system was used to construct qseB, qseC, and qseBC knockout in ATCC43816. No significant alterations in the growth and antibiotic susceptibility were detected between wild-type and mutants. The deletion of qseC led to an increase of biofilm formation, resistance to serum killing, and high mortality in the G. mellonella model. RNAseq differential gene expression analysis exhibited that gene-associated biofilm formation (glgC, glgP, glgA, gcvA, bcsA, ydaM, paaF, ptsG), bacterial type VI secretion system (virB4, virB6, virB10, vgrG, hcp), and biosynthesis of siderophore (entC, entD, entE) were significantly upregulated in comparison with the wild-type control. In addition, qseB, ygiW (encode OB-family protein), and AraC family transcriptional regulator IT767_23090 genes showed highest expressions in the absence of QseC, which might be related to increased virulence. The study provided new insights into the functional importance of QseBC in regulating the virulence of hvKP.}, } @article {pmid35464965, year = {2022}, author = {Petrin, S and Mancin, M and Losasso, C and Deotto, S and Olsen, JE and Barco, L}, title = {Effect of pH and Salinity on the Ability of Salmonella Serotypes to Form Biofilm.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {821679}, pmid = {35464965}, issn = {1664-302X}, abstract = {Salmonella is a major cause of food-borne infections in Europe, and the majority of human infections are caused by only a few serotypes, among them are Salmonella enterica subsp. enterica serotype Enteritidis (hereafter Salmonella Enteritidis), Salmonella Typhimurium, and the monophasic variant of S. Typhimurium. The reason for this is not fully understood, but could include virulence factors as well as increased ability to transfer via the external environment. Formation of biofilm is considered an adaptation strategy used by bacteria to overcome environmental stresses. In order to assess the capability of different Salmonella serotypes to produce biofilm and establish whether this is affected by pH and salinity, 88 Salmonella isolates collected from animal, food, and human sources and belonging to 15 serotypes, including those most frequently responsible for human infections, were tested. Strains were grown in tryptic soy broth (TSB), TSB with 4% NaCl pH 4.5, TSB with 10% NaCl pH 4.5, TSB with 4% NaCl pH 7, or TSB with 10% NaCl pH 7, and biofilm production was assessed after 24 h at 37°C using crystal violet staining. A linear mixed effect model was applied to compare results from the different experimental conditions. Among the tested serotypes, S. Dublin showed the greatest ability to form biofilm even at pH 4.5, which inhibited biofilm production in the other tested serotypes. Salmonella Senftenberg and the monophasic variant of S. Typhimurium showed the highest biofilm production in TSB with 10% NaCl pH 7. In general, pH had a high influence on the ability to form biofilm, and most of the tested strains were not able to produce biofilm at pH 4.5. In contrast, salinity only had a limited influence on biofilm production. In general, serotypes causing the highest number of human infections showed a limited ability to produce biofilm in the tested conditions, indicating that biofilm formation is not a crucial factor in the success of these clones.}, } @article {pmid35464913, year = {2022}, author = {Mettler, MK and Parker, CW and Venkateswaran, K and Peyton, BM}, title = {Antimicrobial Coating Efficacy for Prevention of Pseudomonas aeruginosa Biofilm Growth on ISS Water System Materials.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {874236}, pmid = {35464913}, issn = {1664-302X}, abstract = {Biofilms can lead to biofouling, microbially induced corrosion, physical impediment and eventual loss in function of water systems, and other engineered systems. The remoteness and closed environment of the International Space Station (ISS) make it vulnerable to unchecked biofilm growth; thus, biofilm mitigation strategies are crucial for current ISS operation and future long duration and deep-space crewed missions. In this study, a space flown bacterial strain of Pseudomonas aeruginosa (PA14) was used as a model organism for its ability to form biofilms. Additionally, a novel antimicrobial coating's ability to reduce biofilm accumulation on stainless steel, Teflon, titanium, and Inconel (all used in the ISS water treatment and handling systems) was analyzed. Coated materials demonstrated reductions of P. aeruginosa biofilm across all materials when tested in a continuous flow system with tryptic soy broth medium. However, the coating lost efficacy in potato dextrose broth medium. These findings were corroborated via scanning electron microscopy. This study illustrates the fundamental importance of using multiple approaches to test antibiofilm strategies, as well as the specificity in which conditions such strategies can be implemented.}, } @article {pmid35460772, year = {2022}, author = {Wang, J and He, M and Li, Y and Ma, F and Zheng, P and Hu, B}, title = {Rapid enrichment of denitrifying methanotrophs in a series hollow-fiber membrane biofilm reactor.}, journal = {The Science of the total environment}, volume = {834}, number = {}, pages = {155375}, doi = {10.1016/j.scitotenv.2022.155375}, pmid = {35460772}, issn = {1879-1026}, mesh = {Anaerobiosis ; Archaea ; Bacteria ; Biofilms ; *Bioreactors/microbiology ; *Denitrification ; Methane ; Oxidation-Reduction ; }, abstract = {Denitrifying anaerobic methane oxidation (DAMO) process uses methane as electron donor to reduce nitrate/nitrite to dinitrogen, which is a potentially efficient, low-cost and clean biological nitrogen removal technology. However, slow microbial growth rate severely limits the application of this promising process. In this study, a series hollow-fiber membrane biofilm reactor (HfMBR) was operated for 90 days to achieve rapid enrichment of these denitrifying methanotrophs. Finally, the highest relative abundance of denitrifying methanotrophic archaea and bacteria (DAMO archaea and bacteria) reached 47.5% and 11.3%, respectively. And the average abundance of DAMO archaea and bacteria increased 92.9 and 136.6 times respectively during the 90-day enrichment. High growth rate of DAMO archaea with a doubling time of 11.6 days was achieved in the second HfMBR according to quantitative PCR results. The results implied that dissolved oxygen would inhibit the growth of DAMO archaea, but the series HfMBR could effectively counteract this unfavorable factor. This work provided theoretical guidance for the rapid enrichment of denitrifying methanotrophs and contributed to the application of methane-dependent denitrification process.}, } @article {pmid35458369, year = {2022}, author = {Alfuraydi, RT and Alminderej, FM and Mohamed, NA}, title = {Evaluation of Antimicrobial and Anti-Biofilm Formation Activities of Novel Poly(vinyl alcohol) Hydrogels Reinforced with Crosslinked Chitosan and Silver Nano-Particles.}, journal = {Polymers}, volume = {14}, number = {8}, pages = {}, pmid = {35458369}, issn = {2073-4360}, abstract = {Novel hydrogels were prepared by blending chitosan and poly(vinyl alcohol), PVA, then crosslinking the resulting blends using trimellitic anhydride isothiocyanate at a concentration based on chitosan content in the blends. The weight ratios of chitosan: PVA in the blends were 1:3, 1:1, and 3:1 to produce three hydrogels symbolized as H13, H11, and H31, respectively. For a comparison, H10 was also prepared by crosslinking pure chitosan with trimellitic anhydride isothiocyanate. For further modification, three H31/silver nanocomposites (AgNPs) were synthesized using three different concentrations of silver nitrate to obtain H31/AgNPs1%, H31/AgNPs3% and H31/AgNPs5%. The structures of the prepared samples were emphasized using various analytical techniques. PVA has no inhibition activity against the tested microbes and biofilms. The antimicrobial and anti-biofilm formation activities of the investigated samples was arranged as: H31/AgNPs5% ≥ H31/AgNPs3% > H31/AgNPs1% > H10 > H31 > H11 > H13 > chitosan. H31/AgNPs5% and H31/AgNPs3% were more potent than Vancomycin and Amphotericin B against most of the tested microbes. Interestingly, H31 and H31/AgNPs3% were safe on the normal human cells. Consequently, hydrogels resulting from crosslinked blends of chitosan and PVA loaded with AgNPs in the same structure have significantly reinforced the antimicrobial and inhibition activity against the biofilms of PVA.}, } @article {pmid35457654, year = {2022}, author = {Al-Bayati, M and Samarasinghe, S}, title = {Biofilm and Gene Expression Characteristics of the Carbapenem-Resistant Enterobacterales, Escherichia coli IMP, and Klebsiella pneumoniae NDM-1 Associated with Common Bacterial Infections.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {8}, pages = {}, pmid = {35457654}, issn = {1660-4601}, support = {Ministry of Higher Education and Scientific Research Baghdad / Iraq and Mustansiriyah University (https://uomustansiriyah.edu.iq),//This work is supported by the funding received by the Ministry of Higher Education and Scientific Research Baghdad / Iraq and Mustansiriyah University (https://uomustansiriyah.edu.iq), for a PhD scholarship grant to MA under SS supervision/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacterial Proteins/genetics ; *Biofilms ; Carbapenems/pharmacology ; *Drug Resistance, Bacterial/genetics ; *Enterobacteriaceae Infections/drug therapy ; Escherichia coli/genetics ; *Escherichia coli Infections ; Gene Expression ; Humans ; *Klebsiella Infections/genetics ; Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; beta-Lactamases/genetics/metabolism ; }, abstract = {In light of the limited therapeutic options with Carbapenem-Resistant Enterobacterales (CRE) infections, understanding the bacterial risk factors, such as biofilm formation and related gene expression of CRE, is vital. This study investigates the biofilm formation and biofilm-related gene expression of two enteric Enterobacterales with major CR determinants Escherichia coli IMP and Klebsiella pneumoniae NDM-1, which were seen in high prevalence in most common bacterial infections over the past few years. To our knowledge, this is the first study that demonstrated the relationship between biofilm formation and the related gene expression, to understand the potential molecular mechanisms during the biofilm formation in CRE. Biofilms were quantified by tissue culture plate assay at the stages of the biofilm development: initial attachment (6 h), microcolony formation (12 h), maturation (24 h), and dispersion (48 h). In a dispersion, event bacteria detach without any mechanical means and colonise another area. To investigate the influence of different growth conditions on biofilm formation, biofilms were quantified under different growth conditions. In parallel, quantitative real-time PCR (qPCR) assessed the biofilm-related gene expression of a cluster of genes, including biofilm maturation, quorum sensing, stress survival, and antibiotic resistance. Structural changes during biofilm development were assessed via confocal laser scanning microscopy (CLSM). We observed that the biofilm formation of CRE is correlated with the biofilm development stages, with maximum biofilm observed at 24 h at the maturation stage. Our data also showed that biofilm growth, under the condition tested, is the major factor influencing the variability of biofilm gene expression quantification assays. qPCR analyses have demonstrated that the expression of biofilm-related genes is highly correlated with phenotypic biofilm development, and these findings can be further expanded to understand the variation in regulation of such genes in these significant CRE pathogens. Our study demonstrated that both CRE strains, E. coli IMP and K. pneumoniae NDM-1, are high biofilm formers, and genes involved in biofilm development are upregulated during biofilm growth. The characteristic of the increased biofilm formation with the upregulation of antibiotic-resistant and biofilm-related genes indicates the successful pathogenic role of biofilms of these selected CRE and is attributed to their multi-drug resistance ability and successful dissemination of CRE in common bacterial infections.}, } @article {pmid35457494, year = {2022}, author = {Haghighi, F and Andriasian, L and Tran, NC and Lux, R}, title = {Effect of Cigarette and E-Cigarette Smoke Condensates on Candida albicans Biofilm Formation and Gene Expression.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {8}, pages = {}, pmid = {35457494}, issn = {1660-4601}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; *Cigarette Smoking ; *Electronic Nicotine Delivery Systems ; Gene Expression ; Nicotine/pharmacology ; Tobacco ; *Tobacco Products ; }, abstract = {Smoking triggers environmental changes in the oral cavity and increases the risk of mucosal infections caused by Candida albicans such as oral candidiasis. While cigarette smoke has a significant impact on C. albicans, how e-cigarettes affect this oral pathogen is less clear. Here, we investigated the effect of cigarette and e-cigarette smoke condensates (CSC and ECSC) on C. albicans growth, biofilm formation, and gene expression. Whereas pure nicotine (N) at the minimum inhibitory concentration (MIC, 4 mg/mL) prevented C. albicans growth, enhanced biofilm formation was observed at 0.1 mg/mL. In contrast, at this nicotine sub-MIC (0.1 mg/mL) concentration, CSC and ECSC had no significant effect on C. albicans biofilm formation. Additionally, N, CSC, and ECSC increased the expression of HWP1 and SAP2 genes. The ECSC group exhibited elevated expression levels of the EAP1 and ALS3 genes, compared to the nicotine-free ECSC (-) control. Moreover, our in vitro study illustrated that the antifungal drugs, fluconazole and amphotericin B, alleviated the effect of nicotine on C. albicans gene expression. Overall, the results of the study indicated nicotine from different sources may affect the pathogenic characteristics of C. albicans, including hyphal growth, biofilm formation, and particularly the expression of virulence-related genes.}, } @article {pmid35457206, year = {2022}, author = {Scribani Rossi, C and Barrientos-Moreno, L and Paone, A and Cutruzzolà, F and Paiardini, A and Espinosa-Urgel, M and Rinaldo, S}, title = {Nutrient Sensing and Biofilm Modulation: The Example of L-arginine in Pseudomonas.}, journal = {International journal of molecular sciences}, volume = {23}, number = {8}, pages = {}, pmid = {35457206}, issn = {1422-0067}, support = {RM120172A7AD98EB to SR and AR12117A63EE6037 to CSR//Sapienza University of Rome/ ; PID2019-109372GB-I00//MCIN/AEI/10.13039/501100011033/ ; ERDF A way of making Europe//European Union/ ; Sensing arginine through the Venus Fly Trap domain to control c-di-GMP levels in Pseudomonas aeruginosa: molecular mechanism and metabolic effects of signal transduction.//Istituto Pasteur Italia - Fondazione Cenci Bolognetti/ ; }, mesh = {Arginine/metabolism/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Carbon/metabolism/pharmacology ; *Cyclic GMP/metabolism ; Nitrogen/metabolism/pharmacology ; Nutrients ; Pseudomonas/metabolism ; *Pseudomonas aeruginosa/physiology ; }, abstract = {Bacterial biofilm represents a multicellular community embedded within an extracellular matrix attached to a surface. This lifestyle confers to bacterial cells protection against hostile environments, such as antibiotic treatment and host immune response in case of infections. The Pseudomonas genus is characterised by species producing strong biofilms difficult to be eradicated and by an extraordinary metabolic versatility which may support energy and carbon/nitrogen assimilation under multiple environmental conditions. Nutrient availability can be perceived by a Pseudomonas biofilm which, in turn, readapts its metabolism to finally tune its own formation and dispersion. A growing number of papers is now focusing on the mechanism of nutrient perception as a possible strategy to weaken the biofilm barrier by environmental cues. One of the most important nutrients is amino acid L-arginine, a crucial metabolite sustaining bacterial growth both as a carbon and a nitrogen source. Under low-oxygen conditions, L-arginine may also serve for ATP production, thus allowing bacteria to survive in anaerobic environments. L-arginine has been associated with biofilms, virulence, and antibiotic resistance. L-arginine is also a key precursor of regulatory molecules such as polyamines, whose involvement in biofilm homeostasis is reported. Given the biomedical and biotechnological relevance of biofilm control, the state of the art on the effects mediated by the L-arginine nutrient on biofilm modulation is presented, with a special focus on the Pseudomonas biofilm. Possible biotechnological and biomedical applications are also discussed.}, } @article {pmid35457049, year = {2022}, author = {Wang, S and Liu, XQ and Kang, OH and Kwon, DY}, title = {Combination of Sanguisorbigenin and Conventional Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus: Inhibition of Biofilm Formation and Alteration of Cell Membrane Permeability.}, journal = {International journal of molecular sciences}, volume = {23}, number = {8}, pages = {}, pmid = {35457049}, issn = {1422-0067}, support = {2022//Wonkwang University/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Membrane Permeability ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) infection is challenging to eradicate because of antibiotic resistance and biofilm formation. Novel antimicrobial agents and alternative therapies are urgently needed. This study aimed to evaluate the synergy of sanguisorbigenin (SGB) isolated from Sanguisorba officinalis L. with six conventional antibiotics to achieve broad-spectrum antibacterial action and prevent the development of resistance. A checkerboard dilution test and time-to-kill curve assay were used to determine the synergistic effect of SGB combined with antibiotics against MRSA. SGB showed significant synergy with antibiotics and reduced the minimum inhibitory concentration of antibiotics by 2-16-fold. Biofilm inhibition assay, quantitative RT-PCR, crystal violet absorption, and transmission electron microscopy were performed to evaluate the synergy mechanism. The results indicated that SGB could inhibit biofilm formation and alter cell membrane permeability in MRSA. In addition, SGB was found to exhibit quite low cytotoxicity and hemolysis. The discovery of the superiority of SGB suggests that SGB may be an antibiotic adjuvant for use in combination therapy and as a plant-derived antibacterial agent targeting biofilms.}, } @article {pmid35456851, year = {2022}, author = {Kruppa, O and Czermak, P}, title = {Screening for Biofilm-Stimulating Factors in the Freshwater Planctomycete Planctopirus limnophila to Improve Sessile Growth in a Chemically Defined Medium.}, journal = {Microorganisms}, volume = {10}, number = {4}, pages = {}, pmid = {35456851}, issn = {2076-2607}, support = {LOEWE ZIB//Hessen State Ministry of Higher Education, Research, and the Arts/ ; }, abstract = {Planctomycetes such as Planctopirus limnophila offer a promising source of bioactive molecules, particularly when they switch from planktonic to sessile growth, but little is known about the corresponding biosynthetic gene clusters and how they are activated. We therefore screened for factors that promote sessile growth and biofilm formation to enable the cultivation of P. limnophila in a fixed-bed reactor. We carried out screening in microtiter plates focusing on biofilm formation and changes in optical density in response to various C:N ratios, metal ions, and oxidative stress. We used MTT assays and crystal violet staining to quantify biofilm formation. Positive factors were then validated in a fixed-bed bioreactor. The initial screen showed that D1ASO medium supplemented with NH4Cl to achieve a C:N ratio of 5.7:1, as well as 50 µM FeSO4 or CuSO4, increased the biofilm formation relative to the control medium. Exposure to H2O2 did not affect cell viability but stimulated biofilm formation. However, the same results were not replicated in the fixed-bed bioreactor, probably reflecting conditions that are unique to this environment such as the controlled pH and more vigorous aeration. Although we were able to cultivate P. limnophila in a fixed-bed bioreactor using a chemically defined medium, the factors that stimulate biofilm formation and inhibit planktonic growth were only identified in microtiter plates and further evaluation is required to establish optimal growth conditions in the bioreactor system.}, } @article {pmid35456825, year = {2022}, author = {Thaarup, IC and Iversen, AKS and Lichtenberg, M and Bjarnsholt, T and Jakobsen, TH}, title = {Biofilm Survival Strategies in Chronic Wounds.}, journal = {Microorganisms}, volume = {10}, number = {4}, pages = {}, pmid = {35456825}, issn = {2076-2607}, abstract = {Bacterial biofilms residing in chronic wounds are thought to have numerous survival strategies, making them extremely difficult to eradicate and resulting in long-term infections. However, much of our knowledge regarding biofilm persistence stems from in vitro models and experiments performed in vivo in animal models. While the knowledge obtained from such experiments is highly valuable, its direct translation to the human clinical setting should be undertaken with caution. In this review, we highlight knowledge obtained from human clinical samples in different aspects of biofilm survival strategies. These strategies have been divided into segments of the following attributes: altered transcriptomic profiles, spatial distribution, the production of extracellular polymeric substances, an altered microenvironment, inter-and intra-species interactions, and heterogeneity in the bacterial population. While all these attributes are speculated to contribute to the enhanced persistence of biofilms in chronic wounds, only some of them have been demonstrated to exist in human wounds. Some of the attributes have been observed in other clinical diseases while others have only been observed in vitro. Here, we have strived to clarify the limitations of the current knowledge in regard to this specific topic, without ignoring important in vitro and in vivo observations.}, } @article {pmid35456808, year = {2022}, author = {Kay, W and Hunt, C and Nehring, L and Barnum, B and Ashton, N and Williams, D}, title = {Biofilm Growth on Simulated Fracture Fixation Plates Using a Customized CDC Biofilm Reactor for a Sheep Model of Biofilm-Related Infection.}, journal = {Microorganisms}, volume = {10}, number = {4}, pages = {}, pmid = {35456808}, issn = {2076-2607}, support = {W81XWH-20-1-0384//United States Department of Defense/ ; }, abstract = {Most animal models of infection utilize planktonic bacteria as initial inocula. However, this may not accurately mimic scenarios where bacteria in the biofilm phenotype contaminate a site at the point of injury. We developed a modified CDC biofilm reactor in which biofilms can be grown on the surface of simulated fracture fixation plates. Multiple reactor runs were performed and demonstrated that monomicrobial biofilms of a clinical strain of methicillin-resistant Staphylococcus aureus, S. aureus ATCC 6538, and Pseudomonas aeruginosa ATCC 27853 consistently developed on fixation plates. We also identified a method by which to successfully grow polymicrobial biofilms of S. aureus ATCC 6538 and P. aeruginosa ATCC 27853 on fixation plates. This customized reactor can be used to grow biofilms on simulated fracture fixation plates that can be inoculated in animal models of biofilm implant-related infection that, for example, mimic open fracture scenarios. The reactor provides a method for growing biofilms that can be used as initial inocula and potentially improve the testing and development of antibiofilm technologies.}, } @article {pmid35456793, year = {2022}, author = {Marin, LM and Xiao, Y and Cury, JA and Siqueira, WL}, title = {Engineered Salivary Peptides Reduce Enamel Demineralization Provoked by Cariogenic S. mutans Biofilm.}, journal = {Microorganisms}, volume = {10}, number = {4}, pages = {}, pmid = {35456793}, issn = {2076-2607}, support = {106657/CAPMC/CIHR/Canada ; 400347/CAPMC/CIHR/Canada ; 25116//Canada Foundation for Innovation/ ; 2014/27034-5//São Paulo Research Foundation/ ; 2017/02692-8//São Paulo Research Foundation/ ; }, abstract = {Engineering of the acquired enamel pellicle using salivary peptides has been shown to be a promising anticaries strategy. However, the mechanisms by which these peptides protect teeth against tooth decay are not fully understood. In this study, we evaluated the effect of the engineered salivary peptides DR9-DR9 and DR9-RR14 on enamel demineralization in two experimental conditions: (1) adsorbed onto the enamel surface forming the AEP, and (2) forming the AEP combined with their use to treat the biofilms 2×/day, using a validated cariogenic Streptococcus mutans in vitro biofilm model. Biofilms were grown for 144 h on enamel slabs and then collected to determine the bacterial viability (CFU/biofilm) and biofilm mass (mg protein/biofilm), and to extract cellular/extracellular proteins, which were characterized by mass spectrometry. The culture medium was changed 2×/day to fresh medium, and pH (indicator of biofilm acidogenicity) and calcium concentration (indicator of demineralization) was determined in used medium. DR9-RR14 peptide significantly reduced enamel demineralization (p < 0.0001) in both experimental conditions. However, this peptide did not have a significant effect on biofilm biomass (p > 0.05) nor did it modulate the expression of cellular and extracellular bacterial proteins involved in biofilm cariogenicity. These findings suggest that DR9-RR14 may control caries development mainly by a physicochemical mechanism.}, } @article {pmid35456532, year = {2022}, author = {de Lima, LF and Andrade-Pinheiro, JC and Freitas, MA and da Silva, AI and Fonseca, VJA and da Silva, TG and da Silva, JCP and de Lima, RH and Sales, DL and Neves, RP and de Brito, ES and Ribeiro, PRV and Canuto, KM and Coutinho, HDM and Siyadatpanah, A and Kim, B and Morais-Braga, MFB}, title = {Anti-Candida Properties of Gossypium hirsutum L.: Enhancement of Fungal Growth, Biofilm Production and Antifungal Resistance.}, journal = {Pharmaceutics}, volume = {14}, number = {4}, pages = {}, pmid = {35456532}, issn = {1999-4923}, abstract = {(1) Background: Candida is a genus of yeasts with notable pathogenicity and significant ability to develop antimicrobial resistance. Gossypium hirsutum L., a medicinal plant that is traditionally used due to its antimicrobial properties, has demonstrated significant antifungal activity. Therefore, this study investigated the chemical composition and anti-Candida effects of aqueous (AELG) and hydroethanolic (HELG) extracts obtained from the leaves of this plant. (2) Methods: The extracts were chemically characterized by UPLC-QTOF-MS/MS, and their anti-Candida activities were investigated by analyzing cell viability, biofilm production, morphological transition, and enhancement of antifungal resistance. (3) Results: The UPLC-QTOF-MS/MS analysis revealed the presence of twenty-one compounds in both AELG and HELG, highlighting the predominance of flavonoids. The combination of the extracts with fluconazole significantly reduced its IC50 values against Candida albicans INCQS 40006, Candida tropicalis INCQS 40042, and C. tropicalis URM 4262 strains, indicating enhanced antifungal activity. About biofilm production, significant inhibition was observed only for the AELG-treated C. tropicalis URM 4262 strain in comparison with the untreated control. Accordingly, this extract showed more significant inhibitory effects on the morphological transition of the INCQS 40006 and URM 4387 strains of C. albicans (4) Conclusions: Gossypium hirsutum L. presents promising antifungal effects, that may be potentially linked to the combined activity of chemical constituents identified in its extracts.}, } @article {pmid35456146, year = {2022}, author = {Donadu, MG and Ferrari, M and Mazzarello, V and Zanetti, S and Kushkevych, I and Rittmann, SKR and Stájer, A and Baráth, Z and Szabó, D and Urbán, E and Gajdács, M}, title = {No Correlation between Biofilm-Forming Capacity and Antibiotic Resistance in Environmental Staphylococcus spp.: In Vitro Results.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, pmid = {35456146}, issn = {2076-0817}, abstract = {The production of biofilms is a critical factor in facilitating the survival of Staphylococcus spp. in vivo and in protecting against various environmental noxa. The possible relationship between the antibiotic-resistant phenotype and biofilm-forming capacity has raised considerable interest. The purpose of the study was to assess the interdependence between biofilm-forming capacity and the antibiotic-resistant phenotype in 299 Staphylococcus spp. (S. aureus n = 143, non-aureus staphylococci [NAS] n = 156) of environmental origin. Antimicrobial susceptibility testing and detection of methicillin resistance (MR) was performed. The capacity of isolates to produce biofilms was assessed using Congo red agar (CRA) plates and a crystal violet microtiter-plate-based (CV-MTP) method. MR was identified in 46.9% of S. aureus and 53.8% of NAS isolates (p > 0.05), with resistance to most commonly used drugs being significantly higher in MR isolates compared to methicillin-susceptible isolates. Resistance rates were highest for clindamycin (57.9%), erythromycin (52.2%) and trimethoprim-sulfamethoxazole (51.1%), while susceptibility was retained for most last-resort drugs. Based on the CRA plates, biofilm was produced by 30.8% of S. aureus and 44.9% of NAS (p = 0.014), while based on the CV-MTP method, 51.7% of S. aureus and 62.8% of NAS were identified as strong biofilm producers, respectively (mean OD570 values: S. aureus: 0.779±0.471 vs. NAS: 1.053±0.551; p < 0.001). No significant differences in biofilm formation were observed based on MR (susceptible: 0.824 ± 0.325 vs. resistant: 0.896 ± 0.367; p = 0.101). However, pronounced differences in biofilm formation were identified based on rifampicin susceptibility (S: 0.784 ± 0.281 vs. R: 1.239 ± 0.286; p = 0.011). The mechanistic understanding of the mechanisms Staphylococcus spp. use to withstand harsh environmental and in vivo conditions is crucial to appropriately address the therapy and eradication of these pathogens.}, } @article {pmid35456063, year = {2022}, author = {Sedarat, Z and Taylor-Robinson, AW}, title = {Biofilm Formation by Pathogenic Bacteria: Applying a Staphylococcus aureus Model to Appraise Potential Targets for Therapeutic Intervention.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, pmid = {35456063}, issn = {2076-0817}, abstract = {Carried in the nasal passages by up to 30% of humans, Staphylococcus aureus is recognized to be a successful opportunistic pathogen. It is a frequent cause of infections of the upper respiratory tract, including sinusitis, and of the skin, typically abscesses, as well as of food poisoning and medical device contamination. The antimicrobial resistance of such, often chronic, health conditions is underpinned by the unique structure of bacterial biofilm, which is the focus of increasing research to try to overcome this serious public health challenge. Due to the protective barrier of an exopolysaccharide matrix, bacteria that are embedded within biofilm are highly resistant both to an infected individual's immune response and to any treating antibiotics. An in-depth appraisal of the stepwise progression of biofilm formation by S. aureus, used as a model infection for all cases of bacterial antibiotic resistance, has enhanced understanding of this complicated microscopic structure and served to highlight possible intervention targets for both patient cure and community infection control. While antibiotic therapy offers a practical means of treatment and prevention, the most favorable results are achieved in combination with other methods. This review provides an overview of S. aureus biofilm development, outlines the current range of anti-biofilm agents that are used against each stage and summarizes their relative merits.}, } @article {pmid35455414, year = {2022}, author = {Trognon, J and Vera, G and Rima, M and Stigliani, JL and Amielet, L and El Hage, S and Lajoie, B and Roques, C and El Garah, F}, title = {Investigation of Direct and Retro Chromone-2-Carboxamides Based Analogs of Pseudomonas aeruginosa Quorum Sensing Signal as New Anti-Biofilm Agents.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {15}, number = {4}, pages = {}, pmid = {35455414}, issn = {1424-8247}, support = {Pre-maturation 2020//Regional Council of Occitanie/ ; }, abstract = {Biofilm formation is considered a major cause of therapeutic failure because bacteria in biofilms have higher protection against antimicrobials. Thus, biofilm-related infections are extremely challenging to treat and pose major concerns for public health, along with huge economic impacts. Pseudomonas aeruginosa, in particular, is a “critical priority” pathogen, responsible for severe infections, especially in cystic fibrosis patients because of its capacity to form resistant biofilms. Therefore, new therapeutic approaches are needed to complete the pipeline of molecules offering new targets and modes of action. Biofilm formation is mainly controlled by Quorum Sensing (QS), a communication system based on signaling molecules. In the present study, we employed a molecular docking approach (Autodock Vina) to assess two series of chromones-based compounds as possible ligands for PqsR, a LuxR-type receptor. Most compounds showed good predicted affinities for PqsR, higher than the PQS native ligand. Encouraged by these docking results, we synthesized a library of 34 direct and 25 retro chromone carboxamides using two optimized routes from 2-chromone carboxylic acid as starting material for both series. We evaluated the synthesized carboxamides for their ability to inhibit the biofilm formation of P. aeruginosa in vitro. Overall, results showed several chromone 2-carboxamides of the retro series are potent inhibitors of the formation of P. aeruginosa biofilms (16/25 compound with % inhibition ≥ 50% at 50 μM), without cytotoxicity on Vero cells (IC50 > 1.0 mM). The 2,4-dinitro-N-(4-oxo-4H-chromen-2-yl) benzamide (6n) was the most promising antibiofilm compound, with potential for hit to lead optimization.}, } @article {pmid35455029, year = {2022}, author = {Catovic, C and Abbes, I and Barreau, M and Sauvage, C and Follet, J and Duclairoir-Poc, C and Groboillot, A and Leblanc, S and Svinareff, P and Chevalier, S and Feuilloley, MGJ}, title = {Cotton and Flax Textiles Leachables Impact Differently Cutaneous Staphylococcus aureus and Staphylococcus epidermidis Biofilm Formation and Cytotoxicity.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {35455029}, issn = {2075-1729}, abstract = {Bacteria can bind on clothes, but the impacts of textiles leachables on cutaneous bacteria remain unknown. Here, we studied for the first time the effects of cotton and flax obtained through classical and soft ecological agriculture on the representatives S. aureus and S. epidermidis bacteria of the cutaneous microbiota. Crude flax showed an inhibitory potential on S. epidermidis bacterial lawns whereas cotton had no effect. Textile fiber leachables were produced in bacterial culture media, and these extracts were tested on S. aureus and S. epidermidis. Bacterial growth was not impacted, but investigation by the crystal violet technique and confocal microscopy showed that all extracts affected biofilm formation by the two staphylococci species. An influence of cotton and flax culture conditions was clearly observed. Flax extracts had strong inhibitory impacts and induced the formation of mushroom-like defense structures by S. aureus. Conversely, production of biosurfactant by bacteria and their surface properties were not modified. Resistance to antibiotics also remained unchanged. All textile extracts, and particularly soft organic flax, showed strong inhibitory effects on S. aureus and S. epidermidis cytotoxicity on HaCaT keratinocytes. Analysis of flax leachables showed the presence of benzyl alcohol that could partly explain the effects of flax extracts.}, } @article {pmid35454508, year = {2022}, author = {Zhao, N and Cai, R and Zhang, Y and Wang, X and Zhou, N}, title = {A pH-Gated Functionalized Hollow Mesoporous Silica Delivery System for Photodynamic Sterilization in Staphylococcus aureus Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {8}, pages = {}, pmid = {35454508}, issn = {1996-1944}, support = {42177212 and 21877054//National Natural Science Foundation of China/ ; }, abstract = {Multidrug-resistant bacteria are increasing, particularly those embedded in microbial biofilm. These bacteria account for most microbial infections in humans. Traditional antibiotic treatment has low efficiency in sterilization of biofilm-associated pathogens, and thus the development of new approaches is highly desired. In this study, amino-modified hollow mesoporous silica nanoparticles (AHMSN) were synthesized and used as the carrier to load natural photosensitizer curcumin (Cur). Then glutaraldehyde (GA) and polyethyleneimine (PEI) were used to seal the porous structure of AHMSN by the Schiff base reaction, forming positively charged AHMSN@GA@PEI@Cur. The Cur delivery system can smoothly diffuse into the negatively charged biofilm of Staphylococcus aureus (S. aureus). Then Cur can be released to the biofilm after the pH-gated cleavage of the Schiff base bond in the slightly acidic environment of the biofilm. After the release of the photosensitizer, the biofilm was irradiated by the blue LED light at a wavelength of 450 nm and a power of 37.4 mV/cm[2] for 5 min. Compared with the control group, the number of viable bacteria in the biofilm was reduced by 98.20%. Therefore, the constructed pH-gated photosensitizer delivery system can efficiently target biofilm-associated pathogens and be used for photodynamic sterilization, without the production of antibiotic resistance.}, } @article {pmid35454375, year = {2022}, author = {Grassi, R and Nardi, GM and Mazur, M and Di Giorgio, R and Ottolenghi, L and Guerra, F}, title = {The Dental-BIOfilm Detection TECHnique (D-BioTECH): A Proof of Concept of a Patient-Based Oral Hygiene.}, journal = {Medicina (Kaunas, Lithuania)}, volume = {58}, number = {4}, pages = {}, pmid = {35454375}, issn = {1648-9144}, mesh = {Biofilms ; Biotechnology ; *Health Status ; Humans ; *Oral Hygiene ; Treatment Outcome ; }, abstract = {To date, no strong long-term data have been reported about new innovative clinical protocols to manage oral hygiene. An improper management of oral hygiene may lead to an increase in dental implant failure, and to an increase in infective complications in prosthetic rehabilitation. Personalized techniques are strongly required in dentistry and dental hygiene. A customized and personalized approach to oral hygiene is crucial in ensuring not only effective treatment, but also a careful analysis of the general health status of the patient involved in the therapeutic process. D-BioTECH is an acronym for Dental BIOfilm Detection Technique: it is based on a tailored approach to patients, ensuring that the operator actively interacts with the patient and their specific needs, especially during the domiciliary therapy. D-BioTECH is an approach to preventive care: in D-BioTECH, both dental hygienists and dentists play a central role. The use of a personalized approach to oral hygiene is the first step towards increasing implant and prosthesis survival rate; moreover, personalized medicine is strategic for managing and preventing the biological complications associated with several dental risk factors.}, } @article {pmid35453246, year = {2022}, author = {Goda, RM and El-Baz, AM and Khalaf, EM and Alharbi, NK and Elkhooly, TA and Shohayeb, MM}, title = {Combating Bacterial Biofilm Formation in Urinary Catheter by Green Silver Nanoparticle.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, pmid = {35453246}, issn = {2079-6382}, abstract = {Urinary catheters are commonly associated with urinary tract infections. This study aims to inhibit bacterial colonisation and biofilm of urinary tract catheters. Silicon catheter pieces were varnished with green silver nanoparticles (AgNPs) using Pistacia lentiscus mastic to prevent bacterial colonisation. Pomegranate rind extract was used to synthesize AgNPs. AgNPs were characterized by UV-Vis spectroscopy, X-ray crystallography, and transmission electron microscopy (TEM). Results obtained revealed that the size of most AgNPs ranged between 15-25 nm and they took crystallised metal and oxidised forms. The amounts of released silver ions from 1 cm pieces of catheters coated with AgNPs were estimated for five days and ranged between 10.82 and 4.8 µg. AgNPs coated catheters significantly inhibited the colonisation of catheters by antibiotic-resistant clinical Gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa) bacteria. AgNPs-varnish was more active against Gram-negative bacteria than Gram-positive bacteria. The significant inhibitory effect of coated catheters lasted for 72 h for both Gram-positive and Gram-negative bacteria. Varnishing catheters with AgNPs may help to prevent bacterial colonisation and infections.}, } @article {pmid35453227, year = {2022}, author = {Pandey, RP and Mukherjee, R and Chang, CM}, title = {Emerging Concern with Imminent Therapeutic Strategies for Treating Resistance in Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, pmid = {35453227}, issn = {2079-6382}, abstract = {Biofilm production by bacteria is presumed to be a survival strategy in natural environments. The production of biofilms is known to be influenced by a number of factors. This paper has precisely elaborated on the different factors that directly influence the formation of biofilm. Biofilm has serious consequences for human health, and a variety of infections linked to biofilm have emerged, rapidly increasing the statistics of antimicrobial resistance, which is a global threat. Additionally, to combat resistance in biofilm, various approaches have been developed. Surface modifications, physical removal, and the use of nanoparticles are the recent advances that have enabled drug discovery for treating various biofilm-associated infections. Progress in nanoparticle production has led to the development of a variety of biofilm-fighting strategies. We focus on the present and future therapeutic options that target the critical structural and functional characteristics of microbial biofilms, as well as drug tolerance mechanisms, such as the extracellular matrix, in this review.}, } @article {pmid35451837, year = {2022}, author = {Ernst, S and Volkov, AN and Stark, M and Hölscher, L and Steinert, K and Fetzner, S and Hennecke, U and Drees, SL}, title = {Azetidomonamide and Diazetidomonapyridone Metabolites Control Biofilm Formation and Pigment Synthesis in Pseudomonas aeruginosa.}, journal = {Journal of the American Chemical Society}, volume = {144}, number = {17}, pages = {7676-7685}, doi = {10.1021/jacs.1c13653}, pmid = {35451837}, issn = {1520-5126}, mesh = {*Azetidines ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Pseudomonas aeruginosa/metabolism ; Quorum Sensing/genetics ; Virulence Factors ; }, abstract = {Synthesis of azetidine-derived natural products by the opportunistic pathogen Pseudomonas aeruginosa is controlled by quorum sensing, a process involving the production and sensing of diffusible signal molecules that is decisive for virulence regulation. In this study, we engineered P. aeruginosa for the titratable expression of the biosynthetic aze gene cluster, which allowed the purification and identification of two new products, azetidomonamide C and diazetidomonapyridone. Diazetidomonapyridone was shown to have a highly unusual structure with two azetidine rings and an open-chain diimide moiety. Expression of aze genes strongly increased biofilm formation and production of phenazine and alkyl quinolone virulence factors. Further physiological studies revealed that all effects were mainly mediated by azetidomonamide A and diazetidomonapyridone, whereas azetidomonamides B and C had little or no phenotypic impact. The P450 monooxygenase AzeF which catalyzes a challenging, stereoselective hydroxylation of the azetidine ring converting azetidomonamide C into azetidomonamide A is therefore crucial for biological activity. Based on our findings, we propose this group of metabolites to constitute a new class of diffusible regulatory molecules with community-related effects in P. aeruginosa.}, } @article {pmid35450484, year = {2022}, author = {Babeer, A and Oh, MJ and Ren, Z and Liu, Y and Marques, F and Poly, A and Karabucak, B and Steager, E and Koo, H}, title = {Microrobotics for Precision Biofilm Diagnostics and Treatment.}, journal = {Journal of dental research}, volume = {101}, number = {9}, pages = {1009-1014}, pmid = {35450484}, issn = {1544-0591}, support = {R01 DE025848/DE/NIDCR NIH HHS/United States ; R56 DE029985/DE/NIDCR NIH HHS/United States ; R90 DE031532/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; }, abstract = {Advances in small-scale robotics and nanotechnology are providing previously unimagined opportunities for new diagnostic and therapeutic approaches with high precision, control, and efficiency. We designed microrobots for tetherless biofilm treatment and retrieval using iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality as building blocks. We show 2 distinct microrobotic platforms. The first system is formed from NPs that assemble into aggregated microswarms under magnetic fields that can be controlled to disrupt and retrieve biofilm samples for microbial analysis. The second platform is composed of 3-dimensional (3D) micromolded opacifier-infused soft helicoids with embedded catalytic-magnetic NPs that can be visualized via existing radiographic imaging techniques and controlled magnetically inside the root canal, uninterrupted by the soft and hard tissues surrounding the teeth in an ex vivo model. These microrobots placed inside the root canal can remove biofilms and be efficiently guided with microscale precision. The proof-of-concept paradigm described here can be adapted to target difficult-to-reach anatomical spaces in other natural and implanted surfaces in an automated and tether-free manner.}, } @article {pmid35449342, year = {2022}, author = {Gómez-Alonso, IS and Estrada-Alemán, ID and Martínez-García, S and Peralta, H and Quintana, ET and Guerrero-Barajas, C and Chávez-Cabrera, C and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {The expression of glycosyltransferases sdgA and sdgB in Staphylococcus epidermidis depends on the conditions of biofilm formation.}, journal = {Archives of microbiology}, volume = {204}, number = {5}, pages = {274}, pmid = {35449342}, issn = {1432-072X}, support = {20210987//Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional/ ; }, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Cathepsin G ; Glycosyltransferases/genetics ; Mice ; *Staphylococcal Infections/microbiology ; *Staphylococcus epidermidis/genetics/metabolism ; }, abstract = {The Staphylococcus aureus SdrG protein is glycosylated by SdgA and SdgB for protection against its degradation by the neutrophil cathepsin G. So far, there is no information about the role of Staphylococcus epidermidis SdgA or SdgB in biofilm-forming; therefore, the focus of this work was to determine the distribution and expression of the sdrG, sdgA and sdgB genes in S. epidermidis under in vitro and in vivo biofilm conditions. The frequencies of the sdrG, sdgA and sdgB genes were evaluated by PCR in a collection of 75 isolates. Isolates were grown in dynamic (non-biofilm-forming) or static (biofilm-forming) conditions. The expression of sdrG, sdgA and sdgB was determined by RT-qPCR in cells grown under dynamic conditions (CGDC), as well as in planktonic and sessile cells from a biofilm and cells adhered to a catheter implanted in Balb/c mice. The sdrG and sdgB genes were detected in 100% of isolates, while the sdgA gene was detected in 71% of the sample (p < 0.001). CGDC did not express sdrG, sdgA and sdgB mRNAs. Planktonic and sessile cells expressed sdrG and sdgB, and the same was observed in cells adhered to the catheter. In particular, one isolate, capable of inducing a biofilm under treatment with cathepsin G, expressed sdrG and sdgB in planktonic and sessile cells and cells adhering to the catheter. This suggests that bacteria require biofilm conditions as an important factor for the transcription of the sdgA, sdgB and sdrG genes.}, } @article {pmid35448567, year = {2022}, author = {Ostapska, H and Le Mauff, F and Gravelat, FN and Snarr, BD and Bamford, NC and Van Loon, JC and McKay, G and Nguyen, D and Howell, PL and Sheppard, DC}, title = {Co-Operative Biofilm Interactions between Aspergillus fumigatus and Pseudomonas aeruginosa through Secreted Galactosaminogalactan Exopolysaccharide.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {35448567}, issn = {2309-608X}, support = {558692//Cystic Fibrosis Canada/ ; AM-15//Canadian Glycomics Network (GlycoNet)/ ; W81XWH-15-PRMRP-IIRA//United States Army Medical Command/ ; 81361/CAPMC/CIHR/Canada ; }, abstract = {The mold Aspergillus fumigatus and bacterium Pseudomonas aeruginosa form biofilms in the airways of individuals with cystic fibrosis. Biofilm formation by A. fumigatus depends on the self-produced cationic exopolysaccharide galactosaminogalactan (GAG), while P. aeruginosa biofilms can contain the cationic exopolysaccharide Pel. GAG and Pel are rendered cationic by deacetylation mediated by either the secreted deacetylase Agd3 (A. fumigatus) or the periplasmic deacetylase PelA (P. aeruginosa). Given the similarities between these polymers, the potential for biofilm interactions between these organisms were investigated. P. aeruginosa were observed to adhere to A. fumigatus hyphae in a GAG-dependent manner and to GAG-coated coverslips of A. fumigatus biofilms. In biofilm adherence assays, incubation of P. aeruginosa with A. fumigatus culture supernatants containing de-N-acetylated GAG augmented the formation of adherent P. aeruginosa biofilms, increasing protection against killing by the antibiotic colistin. Fluorescence microscopy demonstrated incorporation of GAG within P. aeruginosa biofilms, suggesting that GAG can serve as an alternate biofilm exopolysaccharide for this bacterium. In contrast, Pel-containing bacterial culture supernatants only augmented the formation of adherent A. fumigatus biofilms when antifungal inhibitory molecules were removed. This study demonstrates biofilm interaction via exopolysaccharides as a potential mechanism of co-operation between these organisms in chronic lung disease.}, } @article {pmid35448388, year = {2022}, author = {Lu, D and Bai, H and Liao, B}, title = {Comparison between Thermophilic and Mesophilic Membrane-Aerated Biofilm Reactors-A Modeling Study.}, journal = {Membranes}, volume = {12}, number = {4}, pages = {}, pmid = {35448388}, issn = {2077-0375}, support = {RGPIN-2014-03727//Natural Sciences and Engineering Research Council/ ; }, abstract = {The concept of thermophilic membrane-aerated biofilm reactor (ThMABR) is studied by modeling. This concept combines the advantages and overcomes the disadvantages of conventional MABR and thermophilic aerobic biological treatment and has great potential to develop a new type of ultra-compact, highly efficient bioreactor for high-strength wastewater and waste gas treatments. Mathematical modeling was conducted to investigate the impact of temperature (mesophilic vs. thermophilic) and oxygen partial pressure on oxygen and substrate concentration profiles, membrane-biofilm interfacial oxygen concentration, oxygen penetration distance, and oxygen and substrate fluxes into biofilms. The general trend of oxygen transfer and substrate flux into biofilm between ThAnMBR and MMABR was verified by the experimental results in the literature. The results from modeling studies indicate that the ThMABR has significant advantages over the conventional mesophilic MABR in terms of improved oxygen and pollutant flux into biofilms and biodegradation rates, and an optimal biofilm thickness exists for maximum oxygen and substrate fluxes into the biofilm.}, } @article {pmid35447572, year = {2022}, author = {Qian, Y and Guo, Y and Shen, J and Qin, Y and Li, YY}, title = {Biofilm growth characterization and treatment performance in a single stage partial nitritation/anammox process with a biofilm carrier.}, journal = {Water research}, volume = {217}, number = {}, pages = {118437}, doi = {10.1016/j.watres.2022.118437}, pmid = {35447572}, issn = {1879-2448}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; Oxidation-Reduction ; Phosphorus ; *Sewage ; Wastewater ; }, abstract = {Biofilm carriers can avoid microorganism washout while maintaining a high amount of biomass, but are also associated with a long biofilm formation period and biofilm aging. A single stage partial nitritation/anammox process (single stage PN/A) reactor was setup to study the biofilm growth characterization and treatment performance under an NLR of 0.53 to 0.90 gN/L/d over one year. Biofilm growth was divided into three stages: the formation stage, maturation stage and aging stage. The initial biofilm was observed at day 84. A nitrogen removal efficiency of 83.4% was achieved at an NLR of 0.90 gN/L/d during the mature biofilm stage. Starvation, nitrogen gas accumulation and hydroxyapatite formation resulted in biofilm aging. After mechanical stirring treatment, biofilm reactivation was achieved by biofilm re-formation within one month. There is clear potential for phosphorus recovery, as indicated by the 5.24% - 6.29% phosphorus content in the biofilm (similar to the 5%-7% phosphorus content in enhanced biological phosphate removal sludge). The AnAOB genera abundance in the biofilm maintained at a high level of 18.25%-32.31%, while the abundance of AnAOB increased from the initial 4.10% to 13.78% after mechanical stirring treatment in the suspended sludge ensured biofilm reactivation. The results of this study clearly show that mechanical stirring treatment can be used to achieve the biofilm reactivation as the biofilm fills with the hollow cylindrical carrier. This study has potential as a useful reference for the realization of the wide application of the biofilm single stage PN/A process in the future.}, } @article {pmid35447397, year = {2022}, author = {Chung, TH and Zakaria, BS and Meshref, MNA and Dhar, BR}, title = {Enhancing quorum sensing in biofilm anode to improve biosensing of naphthenic acids.}, journal = {Biosensors & bioelectronics}, volume = {210}, number = {}, pages = {114275}, doi = {10.1016/j.bios.2022.114275}, pmid = {35447397}, issn = {1873-4235}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Biosensing Techniques ; Carboxylic Acids ; Electrodes ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/metabolism ; *Quorum Sensing/genetics ; }, abstract = {The feasibility of enhancing quorum sensing (QS) in anode biofilm to improve the quantifications of commercial naphthenic acid concentrations (9.4-94 mg/L) in a microbial electrochemical cell (MXC) based biosensor was demonstrated in this study. First, three calibration methods were systematically compared, and the charging-discharging operation was selected for further experiments due to its 71-227 folds higher electrical signal outputs than the continuous closed-circuit operation and cyclic voltammetry modes. Then, the addition of acylase (5 μg/L) as an exogenous QS autoinducer (acylase) was investigated, which further improved the biosensor's electrical signal output by ∼70%, as compared to the control (without acylase). The addition of acylase increased the relative expression of QS-associated genes (lasR, lasI, rhlR, rhlI, lasA, and luxR) by 7-100%, along with increased abundances of known electroactive bacterial genera, such as Geobacter (from 42% to 47%) and Desulfovibrio (from 6% to 11%). Furthermore, toxicities of different NAs concentrations measured with the Microtox bioassay test were correlated with corresponding electrical signals, indicating that MXC-biosensor can provide a dual platform for rapid assessment of both NA concentrations and NA-associated toxicity.}, } @article {pmid35447190, year = {2022}, author = {Wang, T and Zhang, T and Dai, X and Wang, W and Wang, J}, title = {Control strategies for biofilm control in reclaimed water distribution systems from the perspective of microbial antagonism and electrochemistry.}, journal = {The Science of the total environment}, volume = {834}, number = {}, pages = {155289}, doi = {10.1016/j.scitotenv.2022.155289}, pmid = {35447190}, issn = {1879-1026}, mesh = {Antibiosis ; Biofilms ; Electrochemistry ; *Extracellular Polymeric Substance Matrix ; *Water ; }, abstract = {Biofilm formation in reclaimed water (RW) distribution systems presents significant technical challenges to RW utilization. Two main technologies to control biofilm formation, microbial antagonism (MA) and electrochemical oxidation (EO), are not yet widely used in drip irrigation systems (DIS) and their mechanisms of action need further clarification. In this study, we first showed that the MA and EO treatments reduced biofilm formation by about 62% and 68%, respectively, and extracellular polymeric substance (EPS) content by 14% and 49%, respectively, in biofilms compared with raw RW type 1 (R-RW1) in unused pipes, thus effectively improving the performance of DIS. When MA-RW and EO-RW were applied to already clogged systems, the degree of clogging alleviation varied depending on the severity of the original clogging. We recommend adding the antagonist, Bacillus subtilis, to RW at 25% clogging for the maximum effect and to slow the microbial adaptation process. Compared to MA, the recovery effect of EO was slower initially but lasted longer and had a significantly better alleviating effect on severely clogged pipelines. Illumina Mi-SEQ high-throughput sequencing data showed that both MA and EO resulted in a significant decrease in microbial diversity, dynamic changes in bacterial community structure, and disruption of network interaction and network modularity. Meanwhile, both treatments promoted the growth of specific microorganisms, enhanced the interaction between certain microbial components, and improved the efficiency of information, matter, and energy exchange within the modules. In summary, we verified the dredging effect of two strategies on DIS under different water conditions, revealed the differences in their mechanisms of action, and proposed their application scenarios. Our results will help improve the efficiency of RW in agricultural drip irrigation systems and effectively reduce maintenance costs.}, } @article {pmid35445489, year = {2022}, author = {Mahmoudi, M and Sadeghifard, N and Maleki, A and Yeo, CC and Ghafourian, S}, title = {relBE toxin-antitoxin system as a reliable anti-biofilm target in Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {133}, number = {2}, pages = {683-695}, doi = {10.1111/jam.15585}, pmid = {35445489}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; *Antitoxins/genetics/metabolism ; Biofilms ; Humans ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/metabolism ; *Toxin-Antitoxin Systems/genetics ; }, abstract = {AIMS: The ability of the pathogenic bacterium Pseudomonas aeruginosa to produce biofilms has made it more difficult to treat its infections with current antibiotics. Several genes are involved in biofilm production, and toxin-antitoxin (TA) loci have been reported to be responsible for the regulation of biofilm-associated genes. This study was aimed at evaluating various TA loci in P. aeruginosa to find a reliable target in order to disrupt biofilm formation.

METHODS AND RESULTS: Thirty clinical isolates of P. aeruginosa were assessed for biofilm production as well as the presence of various TA loci in their genomes. The relBETA locus was present in all 30 P. aeruginosa isolates but its expression was not detectable in isolates that did not show biofilm production. Quantitative real-time -PCR (q-PCR) also demonstrated that the expression of relBE was higher in isolates with stronger biofilm-producing capability. Knocking out the relBE locus in one biofilm-producing P. aeruginosa isolate led to the cessation of biofilm-producing capacity in that isolate and eliminated the expression of ndvB, which is among the genes involved in biofilm production.

CONCLUSIONS: These results inferred the involvement of relBE TA locus in the regulation of biofilm production in P. aeruginosa and indicated the possibility of relBE as an anti-biofilm target for this pathogen.}, } @article {pmid35443798, year = {2022}, author = {Tuncer, G and Aktas, Z and Basaran, S and Cagatay, A and Eraksoy, H}, title = {Biofilm formation of panresistant Klebsiella pneumoniae.}, journal = {Future microbiology}, volume = {17}, number = {}, pages = {723-735}, doi = {10.2217/fmb-2021-0108}, pmid = {35443798}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Klebsiella Infections ; *Klebsiella pneumoniae ; }, abstract = {Introduction: The authors aimed to investigate the biofilm-forming features of panresistant Klebsiella pneumoniae (PRKp). Material & methods: The biofilm formations were shown under light microscope and laser scanning confocal microscopy. The optical densities of the wells were measured and classified according to biofilm-forming capacities. Results: The ratio of biofilm-forming K. pneumoniae was established to be 100%. All isolates were found to form high-level biofilms in classification compared with positive and negative controls. No significant difference was detected in the biofilm-forming capacities of K. pneumoniae strains isolated from different sample types. Conclusion: No previous study associated with PRKp isolates was identified in the literature search. There is a need for different approaches characterizing the biofilm-forming features of PRKp.}, } @article {pmid35443583, year = {2022}, author = {Bayatipour, Z and Sadeghifard, N and Ghafourian, S and Kalani, BS and Asadollahi, P and Azizi-Jalilian, F and Pakzad, I}, title = {Effect of Chlorhexidine (CHX) and Hydrogen Peroxide (H2O2) on the Biofilm Formation of Enterococcus faecalis.}, journal = {Clinical laboratory}, volume = {68}, number = {4}, pages = {}, doi = {10.7754/Clin.Lab.2021.210458}, pmid = {35443583}, issn = {1433-6510}, mesh = {Biofilms ; *Chlorhexidine/pharmacology ; *Enterococcus faecalis/genetics ; Humans ; Hydrogen Peroxide/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Biofilm makes bacteria resistant to antimicrobial agents and facilitates the transmission of infectious diseases in hospitals. Disinfectant compounds are frequently used to control surface contamination. This study was designed to investigate the effect of chlorhexidine (CHX) and hydrogen peroxide (H2O2) on biofilm formation of Enterococcus faecalis.

METHODS: This study was performed on 40 E. faecalis clinical isolates. After the determination of MIC, the effect of different concentrations of CHX and H2O2 on the biofilm formation was evaluated. Also, the relative expression level of the studied biofilm genes, following exposure to sublethal concentration of CHX and H2O2, was assessed using quantitative reverse transcription PCR (qRT-PCR).

RESULTS: The frequency of the asa1, efaA, epaI, and esp biofilm genes were 80%, 92.5%, 100%, and 75%, respectively. Various concentrations of CHX increased the biofilm mass in E. faecalis. Also, the combination of CHX and H2O2 at sub-minimal inhibitory concentrations, significantly elevated the expression of asa1, epaI, and esp genes.

CONCLUSIONS: The results of this study showed that the improper use of disinfectants can increase the ability of biofilm formation in E. faecalis and may cause selective pressure leading to the emergence of biocide-resistant microorganisms.}, } @article {pmid35441624, year = {2022}, author = {Wang, Y and Shukla, A}, title = {Bacteria-responsive biopolymer-coated nanoparticles for biofilm penetration and eradication.}, journal = {Biomaterials science}, volume = {10}, number = {11}, pages = {2831-2843}, doi = {10.1039/d2bm00361a}, pmid = {35441624}, issn = {2047-4849}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Biopolymers/pharmacology ; *Chitosan/pharmacology ; *Nanoparticles ; }, abstract = {Biofilm infections are common and can be extremely difficult to treat. Nanoparticles that respond to multiple bacterial stimuli have the potential to successfully prevent and eradicate biofilms. Here, we developed a hyaluronic acid and chitosan coated, antibiotic loaded gelatin nanoparticle, which can undergo hyaluronidase- and gelatinase-mediated degradation regulated by chitosan protonation and swelling in the acidic biofilm microenvironment. We examined the antibiofilm properties of these nanoparticles using a Gram-negative biofilm forming pathogenic bacteria, Vibrio vulnificus. Non-drug loaded responsive nanoparticle formulations exhibited excellent biofilm penetration and retention in preformed V. vulnificus biofilms. Drug loaded formulations were found to exhibit excellent biofilm eradication efficacy, eliminating the biofilm matrix and effectively causing bacterial cell death, which was not observed for treatment with free drug at equivalent concentrations. Overall, these multi-stimuli-responsive nanoparticles have the potential to provide effective and efficient antibiofilm treatment.}, } @article {pmid35439517, year = {2022}, author = {Hua, ZL and Wang, YF and Zhang, JY and Li, XQ and Yu, L}, title = {Removal of perfluoroalkyl acids and dynamic succession of biofilm microbial communities in the decomposition process of emergent macrophytes in wetlands.}, journal = {The Science of the total environment}, volume = {834}, number = {}, pages = {155295}, doi = {10.1016/j.scitotenv.2022.155295}, pmid = {35439517}, issn = {1879-1026}, mesh = {Biofilms ; *Fluorocarbons/analysis ; *Microbiota ; *Water Pollutants, Chemical/analysis ; Wetlands ; }, abstract = {Perfluoroalkyl acids (PFAAs) are emerging contaminants that pose significant environmental and health concerns. Water-sediment-macrophyte residue systems were established to clarify the removal efficiency of PFAAs, explore possible removal pathways, and profile the dynamic succession of biofilm microbial communities in the decomposition process. These systems were fortified with 12 PFAAs at three concentration levels. Iris pseudacorus and Alisma orientale were selected as the decomposing emergent macrophytes. The removal rates in the treatments with residues of I. pseudacorus (IP) and A. orientale (AO) were 34.4% to 88.9% and 36.5% to 89.9%, respectively, which were higher than those in the control groups (CG) (30.3% to 86.9%), suggesting that decomposition could alter the removal of PFAAs. Sediment made the greatest contributions (preloaded 14.5% to 77.8% of PFAAs in IP, 14.3% to 78.2% in AO, and 27.4% to 71.9% in CG). PFAAs could also be removed by macrophyte residue sorption (0.0190% to 13.0% in IP and 0.016% to 15.6% in AO) and bioaccumulation of residual biofilm (the contributions of biofilm microbes and their extracellular polymeric substances were 0.0110% to 3.93% and 0.918% to 34.4%, respectively, in IP and 0.0141% to 4.65% and 1.49% to 34.1%, respectively, in AO). Significant correlations were observed between sediment/residue adsorption and bioaccumulation of biofilm microbes, and were significantly correlated with perfluoroalkyl chain length (p < 0.05). The dynamic succession of residual biofilm microbial communities was investigated. The largest difference was found at the preliminary stage. The most similar communities were found in AO on day 70 (with specific genera Macellibacteroides and WCHB1-32) and in IP on day 35 (with specific genera Aeromonas and Flavobacterium). This study is useful to understand the removal of PFAAs during the decomposition process, providing further assistance in removing PFAAs during the life cycle of macrophytes in wetlands.}, } @article {pmid35438974, year = {2022}, author = {Gu, X and Huang, D and Chen, J and Li, X and Zhou, Y and Huang, M and Liu, Y and Yu, P}, title = {Bacterial Inactivation and Biofilm Disruption through Indigenous Prophage Activation Using Low-Intensity Cold Atmospheric Plasma.}, journal = {Environmental science & technology}, volume = {56}, number = {12}, pages = {8920-8931}, doi = {10.1021/acs.est.2c01516}, pmid = {35438974}, issn = {1520-5851}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; *Bacteriophages ; Biofilms ; Escherichia coli ; *Escherichia coli K12 ; *Plasma Gases/pharmacology ; Prophages/physiology ; Reactive Oxygen Species ; }, abstract = {Biofilms can be pervasive and problematic in water treatment and distribution systems but are difficult to eradicate due to hindered penetration of antimicrobial chemicals. Here, we demonstrate that indigenous prophages activated by low-intensity plasma have the potential for efficient bacterial inactivation and biofilm disruption. Specifically, low-intensity plasma treatment (i.e., 35.20 W) elevated the intracellular oxidative reactive species (ROS) levels by 184%, resulting in the activation of prophage lambda (λ) within antibiotic-resistant Escherichia coli K-12 (lambda+) [E. coli (λ+)]. The phage activation efficiency was 6.50-fold higher than the conventional mitomycin C induction. Following a cascading effect, the activated phages were released upon the lysis of E. coli (λ+), which propagated further and lysed phage-susceptible E. coli K-12 (lambda-) [E. coli (λ-)] within the biofilm. Bacterial intracellular ROS analysis and ROS scavenger tests revealed the importance of plasma-generated ROS (e.g., [•]OH, [1]O2, and [•]O2[-]) and associated intracellular oxidative stress on prophage activation. In a mixed-species biofilm on a permeable membrane surface, our "inside-out" strategy could inactivate total bacteria by 49% and increase the membrane flux by 4.33-fold. Furthermore, the metagenomic analysis revealed that the decrease in bacterial abundance was closely associated with the increase in phage levels. As a proof-of-concept, this is the first demonstration of indigenous prophage activations by low-intensity plasma for antibiotic-resistant bacterial inactivation and biofilm eradication, which opens up a new avenue for managing associated microbial problems.}, } @article {pmid35438787, year = {2022}, author = {Hsieh, ML and Kiel, N and Jenkins, LMM and Ng, WL and Knipling, L and Waters, CM and Hinton, DM}, title = {The Vibrio cholerae master regulator for the activation of biofilm biogenesis genes, VpsR, senses both cyclic di-GMP and phosphate.}, journal = {Nucleic acids research}, volume = {50}, number = {8}, pages = {4484-4499}, pmid = {35438787}, issn = {1362-4962}, support = {R01 GM109259/GM/NIGMS NIH HHS/United States ; R01 AI121337/AI/NIAID NIH HHS/United States ; R35 GM139537/GM/NIGMS NIH HHS/United States ; R01 AI158433/AI/NIAID NIH HHS/United States ; F30 GM123632/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; DNA-Binding Proteins/genetics ; DNA-Directed RNA Polymerases/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Phosphates/metabolism ; Sigma Factor/genetics/metabolism ; *Vibrio cholerae/metabolism ; }, abstract = {Vibrio cholerae biofilm formation/maintenance is controlled by myriad factors; chief among these are the regulator VpsR and cyclic di-guanosine monophosphate (c-di-GMP). VpsR has strong sequence similarity to enhancer binding proteins (EBPs) that activate RNA polymerase containing sigma factor σ54. However, we have previously shown that transcription from promoters within the biofilm biogenesis/maintenance pathways uses VpsR, c-di-GMP and RNA polymerase containing the primary sigma factor (σ70). Previous work suggested that phosphorylation of VpsR at a highly conserved aspartate, which is phosphorylated in other EBPs, might also contribute to activation. Using the biofilm biogenesis promoter PvpsL, we show that in the presence of c-di-GMP, either wild type or the phospho-mimic VpsR D59E activates PvpsL transcription, while the phospho-defective D59A variant does not. Furthermore, when c-di-GMP levels are low, acetyl phosphate (Ac∼P) is required for significant VpsR activity in vivo and in vitro. Although these findings argue that VpsR phosphorylation is needed for activation, we show that VpsR is not phosphorylated or acetylated by Ac∼P and either sodium phosphate or potassium phosphate, which are not phosphate donors, fully substitutes for Ac∼P. We conclude that VpsR is an unusual regulator that senses phosphate directly, rather than through phosphorylation, to aid in the decision to form/maintain biofilm.}, } @article {pmid35438634, year = {2022}, author = {Zhang, J and Wu, H and Wang, D and Wang, L and Cui, Y and Zhang, C and Zhao, K and Ma, L}, title = {Intracellular glycosyl hydrolase PslG shapes bacterial cell fate, signaling, and the biofilm development of Pseudomonas aeruginosa.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {35438634}, issn = {2050-084X}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cyclic GMP ; Gene Expression Regulation, Bacterial ; Glycoside Hydrolases/genetics/metabolism ; Polysaccharides ; *Pseudomonas aeruginosa/physiology ; }, abstract = {Biofilm formation is one of most important causes leading to persistent infections. Exopolysaccharides are usually a main component of biofilm matrix. Genes encoding glycosyl hydrolases are often found in gene clusters that are involved in the exopolysaccharide synthesis. It remains elusive about the functions of intracellular glycosyl hydrolase and why a polysaccharide synthesis gene cluster requires a glycosyl hydrolase-encoding gene. Here, we systematically studied the physiologically relevant role of intracellular PslG, a glycosyl hydrolase whose encoding gene is co-transcribed with 15 psl genes, which is responsible for the synthesis of exopolysaccharide PSL, a key biofilm matrix polysaccharide in opportunistic pathogen Pseudomonas aeruginosa. We showed that lack of PslG or its hydrolytic activity in this opportunistic pathogen enhances the signaling function of PSL, changes the relative level of cyclic-di-GMP within daughter cells during cell division and shapes the localization of PSL on bacterial periphery, thus results in long chains of bacterial cells, fast-forming biofilm microcolonies. Our results reveal the important roles of intracellular PslG on the cell fate and biofilm development.}, } @article {pmid35437846, year = {2022}, author = {Visperas, A and Santana, D and Klika, AK and Higuera-Rueda, CA and Piuzzi, NS}, title = {Current treatments for biofilm-associated periprosthetic joint infection and new potential strategies.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {40}, number = {7}, pages = {1477-1491}, pmid = {35437846}, issn = {1554-527X}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Arthritis, Infectious/drug therapy ; Bacteria ; Biofilms ; Debridement ; Humans ; *Prosthesis-Related Infections/drug therapy/microbiology ; }, abstract = {Periprosthetic joint infection (PJI) remains a devastating complication after total joint arthroplasty. Bacteria involved in these infections are notorious for adhering to foreign implanted surfaces and generating a biofilm matrix. These biofilms protect the bacteria from antibiotic treatment and the immune system making eradication difficult. Current treatment strategies including debridement, antibiotics, and implant retention, and one- and two-stage revisions still present a relatively high overall failure rate. One of the main shortcomings that has been associated with this high failure rate is the lack of a robust approach to treating bacterial biofilm. Therefore, in this review, we will highlight new strategies that have the potential to combat PJI by targeting biofilm integrity, therefore giving antibiotics and the immune system access to the internal network of the biofilm structure. This combination antibiofilm/antibiotic therapy may be a new strategy for PJI treatment while promoting implant retention.}, } @article {pmid35436977, year = {2022}, author = {Yin, L and Cheng, B and Tu, J and Shao, Y and Song, X and Pan, X and Qi, K}, title = {YqeH contributes to avian pathogenic Escherichia coli pathogenicity by regulating motility, biofilm formation, and virulence.}, journal = {Veterinary research}, volume = {53}, number = {1}, pages = {30}, pmid = {35436977}, issn = {1297-9716}, support = {31772707//Natural Science Foundation of China/ ; 31972644//Natural Science Foundation of China/ ; 2108085QC137//Natural Science Foundation of Anhui Province/ ; }, mesh = {Animals ; Biofilms ; Chick Embryo ; Chickens ; Escherichia coli/physiology ; *Escherichia coli Infections/veterinary ; *Escherichia coli Proteins/genetics ; *Poultry Diseases ; Virulence ; Virulence Factors/genetics ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is a pathotype of extraintestinal pathogenic E. coli and one of the most serious infectious diseases of poultry. It not only causes great economic losses to the poultry industry, but also poses a serious threat to public health worldwide. Here, we examined the role of YqeH, a transcriptional regulator located at E. coli type III secretion system 2 (ETT2), in APEC pathogenesis. To investigate the effects of YqeH on APEC phenotype and virulence, we constructed a yqeH deletion mutant (APEC40-ΔyqeH) and a complemented strain (APEC40-CΔyqeH) of APEC40. Compared with the wild type (WT), the motility and biofilm formation of APEC40-ΔyqeH were significantly reduced. The yqeH mutant was highly attenuated in a chick infection model compared with WT, and showed severe defects in its adherence to and invasion of chicken embryo fibroblast DF-1 cells. However, the mechanisms underlying these phenomena were unclear. Therefore, we analyzed the transcriptional effects of the yqeH deletion to clarify the regulatory mechanisms of YqeH, and the role of YqeH in APEC virulence. The deletion of yqeH downregulated the transcript levels of several flagellum-, biofilm-, and virulence-related genes. Our results demonstrate that YqeH is involved in APEC pathogenesis, and the reduced virulence of APEC40-ΔyqeH may be related to its reduced motility and biofilm formation.}, } @article {pmid35432252, year = {2022}, author = {Winkelströter, LK and Bezirtzoglou, E and Tulini, FL}, title = {Editorial: Natural Compounds and Novel Sources of Antimicrobial Agents for Food Preservation and Biofilm Control.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {856858}, pmid = {35432252}, issn = {1664-302X}, } @article {pmid35430267, year = {2022}, author = {Chen, X and Tyagi, A and Vijayalakshmi, S and Chelliah, R and Shabbir, U and Oh, DH}, title = {Anti-adhesion and anti-biofilm activity of slightly acidic electrolyzed water combined with sodium benzoate against Streptococcus mutans: A novel ecofriendly oral sanitizer to prevent cariogenesis.}, journal = {Microbial pathogenesis}, volume = {166}, number = {}, pages = {105535}, doi = {10.1016/j.micpath.2022.105535}, pmid = {35430267}, issn = {1096-1208}, mesh = {Biofilms ; *Dental Caries/prevention & control ; Humans ; Sodium Benzoate/pharmacology ; *Streptococcus mutans ; Water ; }, abstract = {Streptococcus mutans (S. mutans) can promote the establishment of high acidic biofilms and therefore have contribution to the development of dental caries. Alleviating the acidic environment and/or disrupting the structure of S. mutans biofilm are effective approaches against dental caries, rather than killing the microorganisms. The anti-biofilm effect of slightly acidic electrolyzed water (SAEW) is entirely based on the hypochlorous acid and ROS generation. In this study, sodium benzoate (NaB) acts as a pH adjuster and enhances SAEW's anti-biofilm activity. The results showed that the SAEW combined with NaB (SAEW + NaB) is highly effective in controlling biofilm. The adhesive strength of biofilm was significantly reduced by SAEW, and NaB was found to have a synergy effect with SAEW. Biofilm treated by SAEW + NaB was entirely removed by 60 s of ultrasonic wave, whereas the untreated biofilm can only be removed to a lesser extent. Atomic force microscope (AFM) analysis revealed that SAEW and NaB reduced the height of S. mutans biofilm. The metabolites derived from biofilm positively changed during the periodic 1-min treat, the production of lactic acid was hindered by the treatment. Altogether, these findings suggested a novel therapeutic intervention against S. mutans biofilm by targeting the cariogenic action.}, } @article {pmid35429876, year = {2022}, author = {Ma, B and Seyedi, S and Wells, E and McCarthy, D and Crosbie, N and Linden, KG}, title = {Inactivation of biofilm-bound bacterial cells using irradiation across UVC wavelengths.}, journal = {Water research}, volume = {217}, number = {}, pages = {118379}, doi = {10.1016/j.watres.2022.118379}, pmid = {35429876}, issn = {1879-2448}, mesh = {Biofilms ; Chlorine ; Disinfection/methods ; *Drinking Water ; Ultraviolet Rays ; *Water Purification/methods ; }, abstract = {Opportunistic pathogens (OPs), such as Pseudomonas spp., Legionella spp., and mycobacteria, have been detected in biofilms in drinking water distribution systems and water storage tanks and pose potential risks to finished drinking water quality and safety. Emerging UV technologies, such as UV light emitting diodes (LEDs) and krypton chloride (KrCl*) excimers, could provide an alternative to chemical-based secondary disinfection (i.e., chlorine or chloramines) for controlling biofilm-bound OPs. UV systems offer long lifetimes, ability to select wavelength, small size with high power density, and limited-to-no disinfection by-product formation. In this study, inactivation of biofilm-bound Pseudomonas aeruginosa cells across different maturities was investigated using five UVC devices with different peak emission wavelengths, including a KrCl* excimer (222 nm), a low pressure mercury vapor lamp (254 nm), and three UV LEDs (260 nm, 270 nm, and 282 nm). The UV transmittance and absorbance through the biofilm structure was also documented for the first time using a unique approach. Our results show all UVC devices can inactivate biofilm-bound P. aeruginosa cells up to a point, among which the UV LED with peak emission at 270 nm provided the best disinfection performance. UV sensitivities of biofilm-bound cells decreased with biofilm maturity and while initial rates of inactivation were high, no more than 1.5-2.5 log reduction was possible. Re-suspended biofilm bacteria in aqueous solution were highly sensitive to UV, reaching greater than 6 log reduction. UV shielding by biofilm constituents was observed and was likely one of the reasons for UV resistance but did not fully explain the difference in UV sensitivity between biofilm-bound cells versus planktonic cells. This study improves upon fundamental knowledge and provides guidance for innovative designs using emerging UV technologies for biofilm and pathogen control in water distribution systems.}, } @article {pmid35429565, year = {2022}, author = {Li, Y and Wang, X and Wang, Y and Sun, Y and Xia, S and Zhao, J}, title = {Effect of biofilm colonization on Pb(II) adsorption onto poly(butylene succinate) microplastic during its biodegradation.}, journal = {The Science of the total environment}, volume = {833}, number = {}, pages = {155251}, doi = {10.1016/j.scitotenv.2022.155251}, pmid = {35429565}, issn = {1879-1026}, mesh = {Adsorption ; Biofilms ; Butylene Glycols ; Ecosystem ; *Metals, Heavy ; Microplastics ; Plastics ; Polymers ; *Water Pollutants, Chemical/analysis ; }, abstract = {Few studies have mentioned the enrichment of heavy metal pollutants on microplastics derived from degradable plastics. This study investigated the adsorption behavior of Pb(II) onto biodegradable poly(butylene succinate) (PBS) microplastics during its biodegradation. The results indicated that Pb(II) adsorbed by biofilm-colonized biodegraded-PBS microplastics (B-PBS) was about 10-folds higher than that of virgin PBS (647.09 μg·g[-1] versus 64.13 μg·g[-1]) due to the biofilm colonization and the degradation of PBS. After removing the biofilm, the biodegraded PBS still had high Pb(II) adsorption capacity, which was attributed to the complexation of Pb(II) and the stably adhered extracellular polymeric substances (EPS). Pb(II) adsorption onto both virgin PBS and B-PBS was highly pH-dependent, its adsorption on virgin PBS was dominated by electrostatic interaction, while as for B-PBS, the adsorption mechanisms mainly involved the coordination/complexation of Pb(II) and the EPS components on the colonized biofilm, surface complexation, and electrostatic interaction. This study suggested that the enrichment of heavy metal pollutants onto the biodegradable microplastics may pose risks to the aquatic ecosystem.}, } @article {pmid35429560, year = {2022}, author = {Suzhen, H and Xuhui, H and Hongkuan, C and Qixuan, S and Xingzhang, L and Zheng, Z}, title = {Role of phosphorus in Vallisneria natans and biofilm exposure to Pb[2+] and Cd[2+] stress.}, journal = {The Science of the total environment}, volume = {835}, number = {}, pages = {155235}, doi = {10.1016/j.scitotenv.2022.155235}, pmid = {35429560}, issn = {1879-1026}, mesh = {Biofilms ; Cadmium/toxicity ; *Hydrocharitaceae/physiology ; Lead/toxicity ; *Phosphorus ; }, abstract = {Phosphorus (P) could improve the stress resistance and adaptability of submerged macrophytes. This study investigated the physiological and biochemical responses of plants exposed to different P and Pb, Cd concentrations. Alterations of protein synthesis, the DNA methylation (5-mC) level, and the microbial community of biofilm were also evaluated. Results indicated that lower P (0.5 mg·L[-1]) could promote plant growth and metal enrichment while mitigating the toxicity of metals. Higher P (5.0 mg·L[-1]) induced a degree of oxidative stress, as confirmed by increased activity of superoxide dismutase, peroxidase, and acid phosphatase, as well as increased malondialdehyde contents. While the variation of metallothionein synthesis and DNA methylation level of the plant was dependent on the level of P and metals in the water. These responses indicated potential mechanisms of P detoxification and intoxication. In addition, more abundant microbial communities were observed in biofilms exposed to P and metals. These findings provide theoretical support for the metal detoxification of P in submerged plants.}, } @article {pmid35429103, year = {2022}, author = {Garakouei, SR and Issazadeh, K and Zamani, H and Rakhshaee, R and Shahriarinour, M}, title = {Characterization of oxaliplatin removal by multispecies bacterial populations in moving bed biofilm and suspended-biomass reactors.}, journal = {Journal of applied microbiology}, volume = {133}, number = {2}, pages = {630-645}, doi = {10.1111/jam.15579}, pmid = {35429103}, issn = {1365-2672}, support = {//University of Guilan/ ; }, mesh = {Bacteria ; Biofilms ; Biomass ; Bioreactors/microbiology ; Oxaliplatin ; Pharmaceutical Preparations ; *Waste Disposal, Fluid/methods ; *Wastewater/microbiology ; }, abstract = {AIMS: This work aimed to characterize the oxaliplatin removal potential of multispecies microbial populations using the suspended-biomass (SB) and moving bed biofilm (MBB) reactors.

METHODS AND RESULTS: Bacterial strains were isolated from pharmaceutical wastewater, their oxaliplatin degrading potential was screened and oxaliplatin removal efficacy in multispecies bacterial populations was investigated using HPLC. Five bacterial strains able to degrade oxaliplatin with an oxaliplatin removal efficacy of 21%-52% were isolated. The synthetic consortium including Xenorhabdus spp., Pantoea agglomerans and Bacillus licheniformis showed the highest potential with an oxaliplatin removal efficacy of 88.6% and 94.0% using the SB and MBB reactors, respectively. Also, the consortium reduced the chemical oxygen demand (COD) by 91.6 and 33% in MBB and SB reactors, respectively. A kinetic study showed a faster oxaliplatin removal in MBB (0.134 kg[-1]) than in the SB reactor (0.101 kg[-1]). Based on the GS/MS analysis, the overall biochemical pathway of oxaliplatin degradation was hypothesized to be initiated through the oxygenation of diamino-dicyclohexan-platinium complex and the cleavage of the aromatic ring.

CONCLUSION: Microbial removal of oxaliplatin using MBB and SB reactors seems to be an efficient and promising approach for oxaliplatin removal in pharmaceutical and hospital wastewater treatment plants.

Employing bacterial populations using the MBB reactor is a promising way to treat pharmaceutical wastewater to reduce the discharge of anticancer drugs into the environment.}, } @article {pmid35428495, year = {2022}, author = {Tran, P and Kopel, J and Ray, C and Reed, J and Reid, TW}, title = {Organo-selenium containing dental sealant inhibits biofilm formation by oral bacteria.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {38}, number = {5}, pages = {848-857}, doi = {10.1016/j.dental.2022.04.006}, pmid = {35428495}, issn = {1879-0097}, mesh = {Biofilms ; *Dental Caries/microbiology/prevention & control ; Humans ; Pit and Fissure Sealants/pharmacology ; *Selenium/pharmacology ; Streptococcus mutans ; }, abstract = {OBJECTIVE: Dental plaque is a complex structure (called a biofilm) that is produced by a community of oral bacteria. As microorganisms accumulate in the oral cavity, bacteria can assemble into biofilms that protect them from antibiotics and disinfectants, which contribute to dental cavities and oral infections that acts as the seed for further infections throughout the body. Therefore, there is great interest in developing dental sealants that can effectively eliminate biofilms formed from an assortment of oral bacteria species.

METHODS: In previous papers, it was shown that both in vivo and in vitro use of organo-selenium dental sealants have the potential to be an effective method for preventing dental caries and plaque formation. However, our previous in vitro study only examined the effect of the organo-selenium sealants on Streptococcus mutans and salivarius. Since that time, this organo-selenium sealant has been changed to improve its curing time.

RESULTS: We showed a selenium containing sealant (SeLECT-DefenseTM) can completely eliminate biofilm formation on the sealant at selenium concentrations of 0.25% and higher, by S. salivarius, S. sanguinis, or S. mutans, individually or in combination. This selenium containing sealant can also completely inhibit the same bacteria from growing under the sealant, while control sealant cannot. The selenium containing sealant was tested for stability and it was found to still kill these same bacteria after soaking for the equivalent of one year in PBS (pH 7.4). It was also found that the combination of the three bacteria were also killed by the selenium sealant, thus ruling out potential synergism of the bacteria in forming resistance.

SIGNIFICANCE: The following study showed that this modified selenium dental sealant effectively eliminates species of bacteria both on and under the dental sealant.}, } @article {pmid35425831, year = {2022}, author = {Zhu, C and Zhao, Y and Zhao, X and Liu, S and Xia, X and Zhang, S and Wang, Y and Zhang, H and Xu, Y and Chen, S and Jiang, J and Wu, Y and Wu, X and Zhang, G and Bai, Y and Hu, J and Fotina, H and Wang, L and Zhang, X}, title = {The Antimicrobial Peptide MPX Can Kill Staphylococcus aureus, Reduce Biofilm Formation, and Effectively Treat Bacterial Skin Infections in Mice.}, journal = {Frontiers in veterinary science}, volume = {9}, number = {}, pages = {819921}, pmid = {35425831}, issn = {2297-1769}, abstract = {Staphylococcus aureus is a common pathogen that can cause pneumonia and a variety of skin diseases. Skin injuries have a high risk of colonization by S. aureus, which increases morbidity and mortality. Due to the emergence of multidrug-resistant strains, antimicrobial peptides are considered to be among the best alternatives to antibiotics due to their unique mechanism of action and other characteristics. MPX is an antibacterial peptide extracted from wasp venom that has antibacterial activity against a variety of bacteria. This study revealed that MPX has good bactericidal activity against S. aureus and that its minimum inhibitory concentration (MIC) is 0.08 μM. MPX (4×MIC) can kill 99.9% of bacteria within 1 h, and MPX has good stability. The research on the bactericidal mechanism found that MPX could destroy the membrane integrity, increase the membrane permeability, change the membrane electromotive force, and cause cellular content leakage, resulting in bactericidal activity. Results from a mouse scratch model experiment results show that MPX can inhibit colonization by S. aureus, which reduces the wound size, decreases inflammation, and promotes wound healing. This study reports the activity of MPX against S. aureus and its mechanism and reveals the ability of MPX to treat S. aureus infection in mice, laying the foundation for the development of new drugs for bacterial infections.}, } @article {pmid35425202, year = {2022}, author = {Zhang, Y and Ma, R and Chu, H and Zhou, X and Yao, T and Zhang, Y}, title = {Evaluation of the performance of different membrane materials for microalgae cultivation on attached biofilm reactors.}, journal = {RSC advances}, volume = {12}, number = {3}, pages = {1451-1459}, pmid = {35425202}, issn = {2046-2069}, abstract = {Attached microalgae production in wastewater is a promising method to further develop biofilm reactors by reducing economic costs associated with biomass separation and harvesting. However, the reliability of materials to support such adherence needs further investigation. Five common microfiltration membranes were evaluated in this study to assess their influence on the efficacy of harvesting Chlorella pyrenoidosa. The material-to-material, algae-to-algae, and algae-to-material interactions were studied based on the Extended Derjaguin, Landau, Verwey, Overbeek (XDLVO) theory. The results showed that Chlorella pyrenoidosa was hydrophobic and that the algae particles derived from this algae type tended to agglomerate. Furthermore, the algae-membrane adhesion free energy further validated the accumulation of biomass in the experiments - the cellulose acetate nitrate (CACN) membrane and the cellulose acetate (CA) membrane obtained an optical biomass production of 59.93 and 51.27 g m[-2]. The presence of these interactions promoted the adhesion of more microalgae particles to the membrane. Moreover, the relationship between the algae-membrane and the distance at which the microalgae approached the membrane surface was simulated. The study indicated that the XDLVO theory could be successfully applied to the mechanism for the adhesion of the attached culture of Chlorella pyrenoidosa to the membrane material.}, } @article {pmid35423457, year = {2021}, author = {Dargahi, A and Shokoohi, R and Asgari, G and Ansari, A and Nematollahi, D and Samarghandi, MR}, title = {Moving-bed biofilm reactor combined with three-dimensional electrochemical pretreatment (MBBR-3DE) for 2,4-D herbicide treatment: application for real wastewater, improvement of biodegradability.}, journal = {RSC advances}, volume = {11}, number = {16}, pages = {9608-9620}, pmid = {35423457}, issn = {2046-2069}, abstract = {2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide that is considered as a carcinogenic and highly toxic contaminant, and due to its biological and chemical stability, its degradation is very difficult. Therefore, this study aimed to investigate a hybrid system's efficiency of three-dimensional electrochemical (3DE) process and a moving bed biofilm reactor (MBBR) in removing 2,4-D herbicides from aqueous solutions. In this experimental study, the electrochemical degradation of 2,4-D herbicide in a 3DE process with a G/β-PbO2 anode was first investigated as a pretreatment process. Then, in the post-treatment stage, MBBR with continuous flow was used. The amount of aeration in the MBBR reactor was 4 L min[-1], and the amount of dissolved oxygen (DO) was in the range of 3-5 mg L[-1]. The effect of various parameters such as hydraulic retention time (HRT) and filling ratio were investigated. The amount of sewage injection was set between 0.001-0.004 L min[-1]. Routine microbiological biochemical tests were used to detect bacteria. BOD5/COD, COD/TOC, AOS, and COS ratio parameters were used to determine the biodegradability of 2.4-D due to the effluent of the 3DE process. The results showed that with increasing current density, decreasing pH, decreasing herbicide concentration and increasing electrolysis time, the herbicide degradation efficiency increased by 3DE pretreatment process. Based on the results of MBBR post-treatment process efficiency, with increasing HRT and filling ratio, the herbicide removal efficiency increased. According to the results, the highest removal efficiencies of 2,4-D and COD herbicides were obtained during HRT of 24 h, and the filling ratio of 70% were 97.33% and 88.95%, respectively. The consortium of 2,4-D degrading bacteria identified in this study included E. coli, Enterobacter spp., Bacillus spp., Alcaligenes spp., Proteus spp., Acinetobacter spp., Pseudomonas spp., Arthrobacter, and Brevundimonas vesicularis. In the MBBR biological process, the reaction kinetics followed the Grau second-order model (R [2] = 0.98). In general, the results showed that the combined process of 3DE with G/β-PbO2 anode and MBBR biological process has relatively high efficiency in 2,4-D herbicide degradation and can be used as a suitable complementary treatment method in wastewater containing non-degradable compounds such as phenoxy herbicides, e.g., 2,4-D should be used.}, } @article {pmid35422789, year = {2022}, author = {Yin, WL and Xie, ZY and Zeng, YH and Zhang, J and Long, H and Ren, W and Zhang, X and Cai, XN and Huang, AY}, title = {Two (p)ppGpp Synthetase Genes, relA and spoT, Are Involved in Regulating Cell Motility, Exopolysaccharides Production, and Biofilm Formation of Vibrio alginolyticus.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {858559}, pmid = {35422789}, issn = {1664-302X}, abstract = {The stringent response mediated by the signal molecule (p)ppGpp is involved in response to multiple environmental stresses and control of various physiological processes. Studies have revealed that (p)ppGpp strongly affects the formation and maintenance of several bacterial biofilms. However, the specific regulatory roles of (p)ppGpp in biofilms, especially in the expression of genes related to cell motility and exopolysaccharides (EPSs) production, remain poorly understood. We recently reported two (p)ppGpp synthetase genes relA and spoT from the epizootic pathogen Vibrio alginolyticus. Herein, we found that the (p)ppGpp synthetase genes of V. alginolyticus contributed to biofilm formation at low cell density and biofilm detachment at high cell density, respectively, in polystyrene microtiter plates. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed that the expression levels of both EPSs and motility associated genes were consistent with the development of biofilms. Besides, the (p)ppGpp synthetase gene spoT was found to be closely involved in the regulation of flagellum, smooth/translucent colony morphology and spotty pellicle at the air-liquid interface. Interestingly, pleiotropic phenotypes of ΔrelAΔspoT were similar to that of the rpoN (σ[54]) deletion mutant. Meanwhile, the absence of (p)ppGpp synthetase genes significantly reduced the expression levels of rpoN at low cell density, suggesting that (p)ppGpp may mediate the formation via positively affecting the alternative sigma factor RpoN. These findings allow us to propose (p)ppGpp as a crucial regulator for biofilm development in V. alginolyticus, in view of the regulatory roles of relA and spoT in cell motility and EPSs production.}, } @article {pmid35421933, year = {2022}, author = {Yehia, FAA and Yousef, N and Askoura, M}, title = {Celastrol mitigates staphyloxanthin biosynthesis and biofilm formation in Staphylococcus aureus via targeting key regulators of virulence; in vitro and in vivo approach.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {106}, pmid = {35421933}, issn = {1471-2180}, mesh = {Animals ; Anti-Bacterial Agents/chemistry ; Biofilms ; Mice ; Molecular Docking Simulation ; Pentacyclic Triterpenes ; *Staphylococcal Infections/drug therapy/microbiology ; *Staphylococcus aureus ; Virulence ; Xanthophylls ; }, abstract = {BACKGROUND: Staphylococcus aureus is a leading cause of human infections. The spread of antibiotic-resistant staphylococci has driven the search for novel strategies to supersede antibiotics use. Thus, targeting bacterial virulence rather than viability could be a possible alternative.

RESULTS: The influence of celastrol on staphyloxanthin (STX) biosynthesis, biofilm formation, antibiotic susceptibility and host pathogenesis in S. aureus has been investigated. Celastrol efficiently reduced STX biosynthesis in S. aureus. Liquid chromatography-mass spectrometry (LC-MS) and molecular docking revealed that celastrol inhibits STX biosynthesis through its effect on CrtM. Quantitative measurement of STX intermediates showed a significant pigment inhibition via interference of celastrol with CrtM and accumulation of its substrate, farnesyl diphosphate. Importantly, celastrol-treated S. aureus was more sensitive to environmental stresses and human blood killing than untreated bacteria. Similarly, inhibition of STX upon celastrol treatment rendered S. aureus more susceptible to membrane targeting antibiotics. In addition to its anti-pigment capability, celastrol exhibits significant anti-biofilm activity against S. aureus as indicated by crystal violet assay and microscopy. Celastrol-treated cells showed deficient exopolysaccharide production and cell hydrophobicity. Moreover, celastrol markedly synergized the action of conventional antibiotics against S. aureus and reduced bacterial pathogenesis in vivo using mice infection model. These findings were further validated using qRT-PCR, demonstrating that celastrol could alter the expression of STX biosynthesis genes as well as biofilm formation related genes and bacterial virulence.

CONCLUSIONS: Celastrol is a novel anti-virulent agent against S. aureus suggesting, a prospective therapeutic role for celastrol as a multi-targeted anti-pathogenic agent.}, } @article {pmid35421561, year = {2022}, author = {Kong, F and Ren, HY and Liu, D and Wang, Z and Nan, J and Ren, NQ and Fu, Q}, title = {Improved decolorization and mineralization of azo dye in an integrated system of anaerobic bioelectrochemical modules and aerobic moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {353}, number = {}, pages = {127147}, doi = {10.1016/j.biortech.2022.127147}, pmid = {35421561}, issn = {1873-2976}, mesh = {Anaerobiosis ; *Azo Compounds/chemistry ; *Biofilms ; Bioreactors ; Coloring Agents/chemistry ; Waste Disposal, Fluid ; }, abstract = {In this study, a stacked integrated system with anaerobic bioelectrochemical system (BES) and aerobic moving bed biofilm reactor (MBBR) was developed to improve the decolorization and mineralization of azo dye. This stacked BES-MBBR exhibited better performance with acid orange (AO7) decolorization of 96.4 ± 0.6% and chemical oxygen demand (COD) removal of 87.7 ± 4.4%. Contribution of each module in the BES and MBBR stages indicated that BES modules enhanced the pretreatment process in AO7 decolorization, and MBBR played an important role in further removal of COD. The mechanism analysis indicated that the azo bond was cleaved with reductive decolorization at biocathode in the anaerobic BES stages, and then the intermediate products can be further oxidized with COD removal in the aerobic MBBR stage. This work demonstrated that the integrated system with stacked anaerobic BES and aerobic MBBR could provide a promising way for the pretreatment and post-treatment of refractory wastewater.}, } @article {pmid35420476, year = {2022}, author = {Honorato, L and de Araujo, JFD and Ellis, CC and Piffer, AC and Pereira, Y and Frases, S and de Sousa Araújo, GR and Pontes, B and Mendes, MT and Pereira, MD and Guimarães, AJ and da Silva, NM and Vargas, G and Joffe, L and Del Poeta, M and Nosanchuk, JD and Zamith-Miranda, D and Dos Reis, FCG and de Oliveira, HC and Rodrigues, ML and de Toledo Martins, S and Alves, LR and Almeida, IC and Nimrichter, L}, title = {Extracellular Vesicles Regulate Biofilm Formation and Yeast-to-Hypha Differentiation in Candida albicans.}, journal = {mBio}, volume = {13}, number = {3}, pages = {e0030122}, pmid = {35420476}, issn = {2150-7511}, support = {I01 BX002624/BX/BLRD VA/United States ; IK6 BX005386/BX/BLRD VA/United States ; R01 AI136934/AI/NIAID NIH HHS/United States ; R01 AI116420/AI/NIAID NIH HHS/United States ; R01 AI125770/AI/NIAID NIH HHS/United States ; U54 MD007592/MD/NIMHD NIH HHS/United States ; R21 AI124797/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; *Candida albicans ; *Extracellular Vesicles ; Fatty Acids/pharmacology ; Hyphae ; Saccharomyces cerevisiae ; }, abstract = {In this study, we investigated the influence of fungal extracellular vesicles (EVs) during biofilm formation and morphogenesis in Candida albicans. Using crystal violet staining and scanning electron microscopy (SEM), we demonstrated that C. albicans EVs inhibited biofilm formation in vitro. By time-lapse microscopy and SEM, we showed that C. albicans EV treatment stopped filamentation and promoted pseudohyphae formation with multiple budding sites. The ability of C. albicans EVs to regulate dimorphism was further compared to EVs isolated from different C. albicans strains, Saccharomyces cerevisiae, and Histoplasma capsulatum. C. albicans EVs from distinct strains inhibited yeast-to-hyphae differentiation with morphological changes occurring in less than 4 h. EVs from S. cerevisiae and H. capsulatum modestly reduced morphogenesis, and the effect was evident after 24 h of incubation. The inhibitory activity of C. albicans EVs on phase transition was promoted by a combination of lipid compounds, which were identified by gas chromatography-tandem mass spectrometry analysis as sesquiterpenes, diterpenes, and fatty acids. Remarkably, C. albicans EVs were also able to reverse filamentation. Finally, C. albicans cells treated with C. albicans EVs for 24 h lost their capacity to penetrate agar and were avirulent when inoculated into Galleria mellonella. Our results indicate that fungal EVs can regulate yeast-to-hypha differentiation, thereby inhibiting biofilm formation and attenuating virulence. IMPORTANCE The ability to undergo morphological changes during adaptation to distinct environments is exploited by Candida albicans and has a direct impact on biofilm formation and virulence. Morphogenesis is controlled by a diversity of stimuli, including osmotic stress, pH, starvation, presence of serum, and microbial components, among others. Apart from external inducers, C. albicans also produces autoregulatory substances. Farnesol and tyrosol are examples of quorum-sensing molecules (QSM) released by C. albicans to regulate yeast-to-hypha conversion. Here, we demonstrate that fungal EVs are messengers impacting biofilm formation, morphogenesis, and virulence in C. albicans. The major players exported in C. albicans EVs included sesquiterpenes, diterpenes, and fatty acids. The understanding of how C. albicans cells communicate to regulate physiology and pathogenesis can lead to novel therapeutic tools to combat candidiasis.}, } @article {pmid35420115, year = {2022}, author = {Huang, Y and Liu, D and Guo, R and Wang, B and Liu, Z and Guo, Y and Dong, J and Lu, Y}, title = {Magnetic-controlled dandelion-like nanocatalytic swarm for targeted biofilm elimination.}, journal = {Nanoscale}, volume = {14}, number = {17}, pages = {6497-6506}, doi = {10.1039/d2nr00765g}, pmid = {35420115}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria ; Biofilms ; Humans ; *Hydrogen Peroxide/pharmacology ; Magnetic Fields ; *Silicon Dioxide/pharmacology ; }, abstract = {Infections caused by drug-resistant strains pose a serious threat to human health. Most bacterial infections are related to biofilms. The generation of a bacterial biofilm greatly reduces the antibacterial efficiency of antibiotics and some traditional antibacterial drugs, and it is very important to develop antibacterial drugs to replace antibiotics. Here, encouraged by the promising magnetic control technology of micro/nanorobots, the synergistic antibacterial strategy of a dandelion-like magnetically-controlled multifunctional hierarchical magnetic biomimetic nanozyme, Fe3O4@SiO2@dendritic mesoporous silica@small-Fe3O4 nanoparticles (FSDMSsF NPs), was developed to be effective against bacterial biofilms. FSDMSsF NPs showed great magnetic properties and peroxidase-like activities, and could act as catalytic carriers for the production of hydroxyl radicals that are highly toxic to bacteria in a low-concentration H2O2 environment, killing planktonic bacteria. The antibacterial rate of FSDMSsF NPs reached 99.5% at a concentration of 200 μg mL[-1]. The synergistic antibacterial mechanisms of the mechanical factor and the chemical factor are further discussed. Under time-varying magnetic swarm control, the antibacterial performance of FSDMSsF NPs against bacteria was significantly improved. On this basis, the elimination effect of FSDMSsF NPs on bacterial biofilms is further discussed. The results showed that FSDMSsF NPs could target and eliminate biofilms through complex channels under the control of magnetic fields. In addition, the system could remove biofilms in occlusions by changing the morphology and movement mode of an FSDMSsF NP swarm under magnetic field control. The current work proposes a facile and physical-chemical synergistic strategy for effective antibacterial therapy. FSDMSsF NPs could effectively kill planktonic bacteria and remove stubborn biofilms through magnetic field guidance, achieving thorough antibacterial efficacy, which has great potential in the treatment of drug-resistant bacterial infections.}, } @article {pmid35419182, year = {2022}, author = {Waikhom, N and Agarwal, N and Jabin, Z and Anand, A}, title = {Antimicrobial effectiveness of Nano Silver Fluoride Varnish in reducing Streptococcus mutans in saliva and plaque biofilm when compared with Chlorhexidine and Sodium Fluoride Varnishes.}, journal = {Journal of clinical and experimental dentistry}, volume = {14}, number = {4}, pages = {e321-e328}, pmid = {35419182}, issn = {1989-5488}, abstract = {BACKGROUND: This in vivo study was done to investigate the antimicrobial effectiveness of Nano Silver fluoride, Sodium fluoride and Chlorhexidine when used as a varnish on Streptococcus mutans (S.mutans) in saliva and plaque biofilm.

MATERIAL AND METHODS: 120 caries free subjects, aged 8-10 years were randomly assigned to four different groups (n=30) - group I: Control, group II: Chlorhexidine varnish (CHX), group III: Sodium fluoride varnish (NaF), group IV: Nano Silver fluoride varnish (NSF). Varnish application was done once at baseline. Saliva and plaque samples were collected at baseline (T0), at the end of 1 month (T1) and 3 months (T3) to evaluate S.mutans levels by culture method, optical density and PCR. OHI-S Index was also recorded for clinical evaluation.

RESULTS: NSF, CHX and NaF were effective against S.mutans activity. The intragroup comparision of CFU/ml and OD/ml count showed a highly significant reduction from baseline to 3 months for all the 3 varnish groups (p=0.001). PCR result revealed that maximum reduction was seen in NSF and CHX followed by NaF group.

CONCLUSIONS: NSF reduces S.mutans level in both saliva and plaque biofilm and it is more advantageous than CHX and NaF as it has dual properties of acting as an antibacterial as well as a remineralizing agent. Key words:Chlorhexidine, Nano Silver fluoride, Sodium fluoride, S. mutans, varnish.}, } @article {pmid35418275, year = {2022}, author = {Vale, GC and Carvalho, GAO and Hoogenkamp, M and Exterkate, R and Crielaard, W and Ten Cate, J}, title = {Effect of high-fluoride dentifrice on root dentine and bacterial composition in a multispecies biofilm model.}, journal = {Biofouling}, volume = {38}, number = {4}, pages = {348-354}, doi = {10.1080/08927014.2022.2065199}, pmid = {35418275}, issn = {1029-2454}, mesh = {Animals ; Bacteria ; Biofilms ; Cariostatic Agents/pharmacology ; Cattle ; *Dentifrices/chemistry/pharmacology/therapeutic use ; Dentin/microbiology ; Fluorides/pharmacology ; *Tooth Demineralization/drug therapy/microbiology/prevention & control ; }, abstract = {The present study evaluated the effect of high-fluoride dentifrice on dentine demineralization and bacterial composition in a multispecies biofilm model in vitro. A seven-organism bacterial consortium was grown on bovine dentine discs in a high-throughput active attachment model. The biofilms were submitted twice per day to the following dentifrices treatments: 5,000 ppm F, 1,100 ppm F, with placebo as a negative control. After 5 days of biofilm growth, dentine samples were assessed by transversal microradiography, the biofilm was collected for bacterial counts and the pH of the media was determined. Lower integrated mineral loss values were observed when 5,000 ppm F-treatment was used compared to the other treatments. Overall microbiological counts decreased with increasing F-concentration as well the pH of the media throughout the experiment. The 5,000 ppm F-treatment caused a shift in microbial composition and reduced dentine demineralization in the in-vitro experimental model.}, } @article {pmid35418164, year = {2022}, author = {Lin, Y and Xu, X and Maróti, G and Strube, ML and Kovács, ÁT}, title = {Adaptation and phenotypic diversification of Bacillus thuringiensis biofilm are accompanied by fuzzy spreader morphotypes.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {27}, pmid = {35418164}, issn = {2055-5008}, mesh = {Bacillus cereus ; *Bacillus thuringiensis/genetics ; Biofilms ; DNA Transposable Elements ; }, abstract = {Bacillus cereus group (Bacillus cereus sensu lato) has a diverse ecology, including various species that produce biofilms on abiotic and biotic surfaces. While genetic and morphological diversification enables the adaptation of multicellular communities, this area remains largely unknown in the Bacillus cereus group. In this work, we dissected the experimental evolution of Bacillus thuringiensis 407 Cry- during continuous recolonization of plastic beads. We observed the evolution of a distinct colony morphotype that we named fuzzy spreader (FS) variant. Most multicellular traits of the FS variant displayed higher competitive ability versus the ancestral strain, suggesting an important role for diversification in the adaptation of B. thuringiensis to the biofilm lifestyle. Further genetic characterization of FS variant revealed the disruption of a guanylyltransferase gene by an insertion sequence (IS) element, which could be similarly observed in the genome of a natural isolate. The evolved FS and the deletion mutant in the guanylyltransferase gene (Bt407ΔrfbM) displayed similarly altered aggregation and hydrophobicity compared to the ancestor strain, suggesting that the adaptation process highly depends on the physical adhesive forces.}, } @article {pmid35417624, year = {2022}, author = {Tlais, AZA and Polo, A and Filannino, P and Cantatore, V and Gobbetti, M and Di Cagno, R}, title = {Biofilm formation as an extra gear for Apilactobacillus kunkeei to counter the threat of agrochemicals in honeybee crop.}, journal = {Microbial biotechnology}, volume = {15}, number = {8}, pages = {2160-2175}, pmid = {35417624}, issn = {1751-7915}, mesh = {*Agrochemicals/metabolism/pharmacology ; Animals ; Bees ; Biofilms ; Lactobacillus/metabolism ; *Nicotine/metabolism/pharmacology ; }, abstract = {The alteration of a eubiosis status in honeybees' gut microbiota is directly linked to the occurrence of diseases, and likely to the honeybees decline. Since fructophilic lactobacilli were suggested as symbionts for honeybees, we mechanistically investigated their behaviour under the exposure to agrochemicals (Roundup, Mediator and Reldan containing glyphosate, imidacloprid and chlorpyrifos-methyl as active ingredients respectively) and plant secondary metabolites (nicotine and p-coumaric acid) ingested by honeybees as part of their diet. The effects of exposure to agrochemicals and plant secondary metabolites were assessed both on planktonic cells and sessile communities of three biofilm-forming strains of Apilactobacillus kunkeei. We identified the high sensitivity of A. kunkeei planktonic cells to Roundup and Reldan, while cells embedded in mature biofilms had increased resistance to the same agrochemicals. However, agrochemicals still exerted a substantial inhibitory/control effect if the exposure was during the preliminary steps of biofilm formation. The level of susceptibility resulted to be strain-specific. Exopolysaccharides resulted in the main component of extracellular polymeric matrix (ECM) in biofilm, but the exposure to Roundup caused a change in ECM production and composition. Nicotine and p-coumaric acid had a growth-promoting effect in sessile communities, although no effect was found on planktonic growth.}, } @article {pmid35416708, year = {2022}, author = {Landlinger, C and Oberbauer, V and Podpera Tisakova, L and Schwebs, T and Berdaguer, R and Van Simaey, L and Vaneechoutte, M and Corsini, L}, title = {Preclinical Data on the Gardnerella-Specific Endolysin PM-477 Indicate Its Potential to Improve the Treatment of Bacterial Vaginosis through Enhanced Biofilm Removal and Avoidance of Resistance.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {5}, pages = {e0231921}, pmid = {35416708}, issn = {1098-6596}, mesh = {Biofilms ; Clindamycin/pharmacology/therapeutic use ; Endopeptidases ; Female ; Gardnerella ; Gardnerella vaginalis ; Humans ; Metronidazole/therapeutic use ; *Vaginosis, Bacterial/drug therapy/microbiology ; }, abstract = {Antibiotics are the mainstay of therapy for bacterial vaginosis (BV). However, the rate of treatment failure in patients with recurrent BV is about 50%. Herein, we investigated potential mechanisms of therapy failure, including the propensity of resistance formation and biofilm activity of metronidazole (MDZ), clindamycin (CLI), and PM-477, a novel investigational candidate that is a genetically engineered endolysin with specificity for bacteria of the genus Gardnerella. Determination of the MIC indicated that 60% of a panel of 22 Gardnerella isolates of four different species were resistant to MDZ, while all strains were highly susceptible to CLI and to the endolysin PM-477. Six strains, all of which were initially susceptible to MDZ, were passaged with MDZ or its more potent hydroxy metabolite. All of them generated full resistance after 5 to 10 passages, resulting in MICs of >512 μg/mL. In contrast, only a mild increase in MIC was found for PM-477. There was also no cross-resistance formation, as MDZ-resistant Gardnerella strains remained highly susceptible to PM-477, both in suspension and in preformed biofilms. Strains that were resistant to MDZ in suspension were also tolerant to MDZ at >2,048 μg/mL when growing as biofilm. All strains were susceptible to PM-477 when grown as preformed biofilms, at minimum biofilm eradication concentrations (MBECs) in the range of 1 to 4 μg/mL. Surprisingly, the MBEC of CLI was >512 μg/mL for 7 out of 9 tested Gardnerella strains, all of which were susceptible to CLI when growing in suspension. The observed challenges of MDZ and CLI due to resistance formation and ineffectiveness on biofilm, respectively, could be one explanation for the frequent treatment failures in uncomplicated or recurrent BV. Therefore, the high efficacy of PM-477 in eliminating Gardnerella in in vitro biofilms, as well as its high resilience to resistance formation, makes PM-477 a promising potential alternative for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.}, } @article {pmid35416687, year = {2022}, author = {Sass, A and Vandenbussche, I and Bellich, B and Cescutti, P and Coenye, T}, title = {Pellicle Biofilm Formation in Burkholderia cenocepacia J2315 is Epigenetically Regulated through WspH, a Hybrid Two-Component System Kinase-Response Regulator.}, journal = {Journal of bacteriology}, volume = {204}, number = {5}, pages = {e0001722}, pmid = {35416687}, issn = {1098-5530}, support = {BOFDOC2016001301//UGent | Bijzonder Onderzoeksfonds UGent (BOF)/ ; }, mesh = {Anti-Bacterial Agents/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Burkholderia cenocepacia/metabolism ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial ; Histidine Kinase/genetics/metabolism ; Humans ; Oxygen/metabolism ; }, abstract = {The chemosensory signal transduction system Wsp regulates biofilm formation and related phenotypes by influencing cyclic-di-GMP (c-di-GMP) levels in bacterial cells. This is typically achieved by activation of the diguanylate cyclase WspR, through phosphorylation of its phosphoreceiver domain. The Wsp system of Burkholderia cenocepacia J2315 is in one operon with the hybrid response regulator/histidine kinase wspH, but lacks the diguanylate cyclase wspR which is located in a different operon. The expression of wspH, the first gene in the B. cenocepacia Wsp operon as well as pellicle biofilm formation are epigenetically regulated in B. cenocepacia J2315. To investigate whether WspH regulates pellicle biofilm formation, several mutants with altered expression of wspH were constructed. Mutants with increased expression of wspH showed accelerated pellicle biofilm formation, reduced swimming motility and increased c-di-GMP levels. This was independent of WspR phosphorylation, showing that WspR is not the cognate response receiver for histidine kinase WspH. IMPORTANCE Biofilms are surface-attached or suspended aggregates of cells, that are problematic in the context of bacterial infections, as they provide protection from antibiotic treatment. Burkholderia cenocepacia can colonize the lung of immunocompromised patients and forms biofilms that increase its recalcitrance to antibiotic treatment. Pellicles are biofilms which form at an air-liquid interface to take advantage of the higher oxygen concentrations in this environment. How quickly pellicles are formed is crucial for the fitness of obligate aerobic bacteria such as B. cenocepacia. Cyclic-di-GMP (c-di-GMP) levels determine the transition between planktonic and biofilm lifestyle, and WspH controls c-di-GMP production. WspH is therefore important for the fitness of B. cenocepacia in environments with gradients in oxygen concentration, such as the human lung.}, } @article {pmid35416682, year = {2022}, author = {Wu, J and Jiang, X and Yang, Q and Zhang, Y and Wang, C and Huang, R}, title = {Inhibition of Streptococcus mutans Biofilm Formation by the Joint Action of Oxyresveratrol and Lactobacillus casei.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {9}, pages = {e0243621}, pmid = {35416682}, issn = {1098-5336}, mesh = {Biofilms ; *Dental Caries ; *Dental Plaque ; Glucans ; Humans ; *Lacticaseibacillus casei ; Plant Extracts ; Polyphenols/pharmacology ; Stilbenes ; Streptococcus mutans/genetics ; Water/pharmacology ; }, abstract = {Microbial dysbiosis in dental plaque contributes to the occurrence of dental caries, to which Streptococcus mutans is a major contributor. Lactobacillus casei can be used as probiotic therapy to treat caries by replacing S. mutans within the dental plaque. However, the effects of probiotic treatment are not always stable. Oxyresveratrol (ORV), a plant-derived polyphenol, displays opposite effects in that it inhibits cariogenic and promotes commensal bacteria. Thus, the objectives of this study are to investigate the effects of ORV on bacterial proportions in S. mutans-L. casei biofilm and to elucidate how ORV weakens the competitiveness of S. mutans. Quantitative real-time PCR confirms a decreased S. mutans-L. casei ratio in dual-species biofilm by action of ORV. The culture supernatant of L. casei after being incubated with ORV (ORVLC) is prepared to explore the joint action of ORV and L. casei. ORVLC displays the strongest anti-biofilm effect against S. mutans when compared with the effects of L. casei supernatant or ORV alone. As a result of this treatment, both exopolysaccharides and bacteria contents in the biofilm are greatly reduced. The biofilm is transformed from water-insoluble glucan-dominant to water-soluble glucan-dominant by ORVLC through the modulation of the glycometabolism-related genes of S. mutans. As for the interactions between ORV and L. casei, ORV promotes L. casei to produce acetic acid, which provides L. casei with a competitive advantage against S. mutans. Taken together, ORV may be very suitable as an adjuvant medicine for probiotic therapy in the control of dental caries. IMPORTANCE The homeostatic imbalance in dental plaque associated with a sharp increase in the number of cariogenic bacteria such as Streptococcus mutans is critical for the occurrence and development of caries. Probiotic therapy can restore ecological balance by replacing cariogenic pathogens with probiotics. The current study innovatively finds that oxyresveratrol, a natural polyphenol, can provide probiotic Lactobacillus casei with competitive dominance in its dual-species biofilm with S. mutans. The joint action of oxyresveratrol and L. casei strongly inhibits the biofilm formation of S. mutans. Additionally, oxyresveratrol promotes L. casei to produce acetic acid, which facilitates L. casei to compete with S. mutans. Through the effects of these two mechanisms, oxyresveratrol leads to a significantly decreased S. mutans-L. casei ratio in their dual-species biofilm. Thus, oxyresveratrol is speculated to be an ideal medicine for the prevention and treatment of caries by regulating oral flora balance.}, } @article {pmid35414993, year = {2022}, author = {Choi, H and Zaki, FR and Monroy, GL and Won, J and Boppart, SA}, title = {Imaging and characterization of transitions in biofilm morphology via anomalous diffusion following environmental perturbation.}, journal = {Biomedical optics express}, volume = {13}, number = {3}, pages = {1654-1670}, pmid = {35414993}, issn = {2156-7085}, support = {R01 EB013723/EB/NIBIB NIH HHS/United States ; R01 EB028615/EB/NIBIB NIH HHS/United States ; }, abstract = {Microorganisms form macroscopic structures for the purpose of environmental adaptation. Sudden environmental perturbations induce dynamics that cause bacterial biofilm morphology to transit to another equilibrium state, thought to be related to anomalous diffusion processes. Here, detecting the super-diffusion characteristics would offer a long-sought goal for a rapid detection method of biofilm phenotypes based on their dynamics, such as growth or dispersal. In this paper, phase-sensitive Doppler optical coherence tomography (OCT) and dynamic light scattering (DLS) are combined to demonstrate wide field-of-view and label-free internal dynamic imaging of biofilms. The probability density functions (PDFs) of phase displacement of the backscattered light and the dynamic characteristics of the PDFs are estimated by a simplified mixed Cauchy and Gaussian model. This model can quantify the super-diffusion state and estimate the dynamic characteristics and macroscopic responses in biofilms that may further describe dispersion and growth in biofilm models.}, } @article {pmid35414488, year = {2022}, author = {Narasimman, M and Ory, J and Bartra, SS and Plano, GV and Ramasamy, R}, title = {Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis.}, journal = {The journal of sexual medicine}, volume = {19}, number = {6}, pages = {1024-1031}, doi = {10.1016/j.jsxm.2022.03.602}, pmid = {35414488}, issn = {1743-6109}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Gentamicins/pharmacology ; Gentian Violet ; Humans ; *Penile Prosthesis ; Rifampin/therapeutic use ; Staphylococcus aureus ; }, abstract = {BACKGROUND: Delayed infection, thought to be due to gradual biofilm formation, remains a feared complication after inflatable penile prosthesis (IPP) insertion. Understanding and preventing biofilm formation is necessary to prevent infections.

AIM: To develop an in vitro model and compare growth of biofilm by different bacteria on IPPs and evaluate the anti-infective efficacy of the Coloplast Titan and AMS 700 InhibiZone.

METHODS: Sterile IPPs (Coloplast) were cut into rings and incubated with S. epidermidis, S. aureus, P. aeruginosa, A. baumannii, or K. pneumoniae cultures in tryptic soy broth (TSB) (4 hour) to ensure adequate bacteria attachment, and then in only TSB (120 hours) to allow for biofilm formation. Rings were fixed with ethanol and biofilm measured by spectrophotometer (OD570) after crystal violet staining. This methodology was repeated for S. epidermidis and P. aeruginosa with Coloplast rings dipped in 10 ml of a 10 mg/ml Rifampin, 1 mg/ml Gentamicin, and deionized water solution and undipped AMS InhibiZone rings. Crystal violet assay (OD570) was repeated after incubation within bacteria (2 hour), and then only TSB (120 hours).

OUTCOMES: The primary outcome of the study was OD570 readings, indirectly measuring biofilm mass on implant rings.

RESULTS: S. epidermidis, S. aureus, A. baumannii, P. aeruginosa, and K. pneumoniae all formed significant biofilm. P. aeruginosa showed the strongest predilection to grow biofilm on IPPs. P. aeruginosa also formed significant biofilm on antibiotic-treated Coloplast and AMS rings, while S. epidermidis was inhibited. No significant difference was found in biofilm inhibition between the implants.

CLINICAL TRANSLATION: Our findings suggest gram-negative bacteria may form biofilm more proficiently and quickly on IPPs than gram-positive organisms. Commonly used antibiotic treatments on IPPs may be effective against S. epidermidis but not against P. aeruginosa biofilm formation.

STRENGTHS & LIMITATIONS: This is the first study comparing biofilm formation by different bacteria organisms on IPPs and the inhibitive ability of Coloplast and AMS implants against biofilm formation. Clinical data on organisms responsible for infected IPPs is needed to determine the clinical relevance of our findings.

CONCLUSION: Our novel in vitro model of biofilm formation of IPPs evaluated the effect of a gentamicin/rifampin antibiotic dip on Coloplast Titan implants and the anti-infective capacity of the minocycline/rifampin precoated AMS 700 InhibiZone against S. epidermidis and P. aeruginosa. P. aeruginosa was able to grow on both antibiotic-treated implants, with no significant difference, and should continue to be a specific target of investigation to reduce delayed post-operative IPP infections. Narasimman M, Ory J, Bartra SS, et al. Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis. J Sex Med 2022;19:1024-1031.}, } @article {pmid35411160, year = {2022}, author = {Hou, C and Yin, F and Wang, S and Zhao, A and Li, Y and Liu, Y}, title = {Helicobacter pylori Biofilm-Related Drug Resistance and New Developments in Its Anti-Biofilm Agents.}, journal = {Infection and drug resistance}, volume = {15}, number = {}, pages = {1561-1571}, pmid = {35411160}, issn = {1178-6973}, abstract = {Helicobacter pylori is one of the most common pathogenic bacterium worldwide, infecting about 50% of the world's population. It is a major cause of several upper gastrointestinal diseases, including peptic ulcers and gastric cancer. The emergence of H. pylori resistance to antibiotics has been a major clinical challenge in the field of gastroenterology. In the course of H. pylori infection, some bacteria invade the gastric epithelium and are encapsulated into a self-produced matrix to form biofilms that protect the bacteria from external threats. Bacteria with biofilm structures can be up to 1000 times more resistant to antibiotics than planktonic bacteria. This implies that targeting biofilms might be an effective strategy to alleviate H. pylori drug resistance. Therefore, it is important to develop drugs that can eliminate or disperse biofilms. In recent years, anti-biofilm agents have been investigated as alternative or complementary therapies to antibiotics to reduce the rate of drug resistance. This article discusses the formation of H. pylori biofilms, the relationship between biofilms and drug resistance in H. pylori, and the recent developments in the research of anti-biofilm agents targeting H. pylori drug resistance.}, } @article {pmid35410595, year = {2022}, author = {Bharti, S and Zakir, F and Mirza, MA and Aggarwal, G}, title = {Antifungal Biofilm Strategies: A Less Explored Area in Wound Management.}, journal = {Current pharmaceutical biotechnology}, volume = {23}, number = {12}, pages = {1497-1513}, doi = {10.2174/1389201023666220411100214}, pmid = {35410595}, issn = {1873-4316}, mesh = {*Anti-Infective Agents ; *Antifungal Agents/pharmacology/therapeutic use ; Bacteria ; Biofilms ; Drug Resistance, Fungal ; }, abstract = {BACKGROUND: The treatment of wound-associated infections has always remained a challenge for clinicians, with the major deterring factor being microbial biofilms, majorly bacterial or fungal. Biofilm infections are becoming a global concern owing to resistance to antimicrobials. Various fungal pathogens form fungal biofilms, namely Candida sp., Aspergillus fumigates, Trichosporon sp., Saccharomyces cerevisiae, Cryptococcus neoformans, among others. The rising cases of fungal biofilm resistance add to the burden of wound care. Additionally, with an increase in the number of surgical procedures, transplantation, and the exponential use of medical devices, the fungal bioburden is rising.

OBJECTIVES: The review discusses the methods of biofilm formation and the resistance mechanisms against conventional treatments. The potential of novel delivery strategies and the mechanisms involved therein are also highlighted. Further, the prospects of nanotechnology-based medical devices to combat fungal biofilm resistance have been explored. Some clinical trials and up-to-date patent technologies to eradicate biofilms are also mentioned.

CONCLUSION: Due to the many challenges faced in preventing/eradicating biofilms, only a handful of approaches have made it to the market. Eradication of fungal biofilms are a fragmentary area that needs further exploration.}, } @article {pmid35410114, year = {2022}, author = {Liu, K and Tan, S and Ye, W and Hou, L and Fang, B}, title = {Low-concentration iron promotes Klebsiella pneumoniae biofilm formation by suppressing succinic acid.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {95}, pmid = {35410114}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Iron/pharmacology ; *Klebsiella pneumoniae ; *Succinic Acid/pharmacology ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is widely distributed in water and plays a major role in both human and poultry infections. Many K. pneumoniae strains form biofilms on various surfaces, enhancing their pathogenicity and resistance to antibiotics. The water supply pipeline of chicken farms has become a hotbed for the growth of K pneumoniae biofilm because of its humid environment, and because the chicken drinking water pipeline is thin, it is easily blocked by the biofilm, and the diffused cells can cause repeated and persistent infections. Iron is vital to the growth of microorganisms and the formation of biofilms. Therefore, the aim of this study was to examine the effects of iron on K. pneumoniae biofilm formation and any associated metabolic changes to provide a rationale for reducing the formation of biofilms.

RESULTS: Biofilm formation was enhanced to the greatest extent by the presence of 0.16 mM FeCl2, producing a denser structure under electron microscopy. The number of biofilm-forming and planktonic bacteria did not change, but protein and polysaccharide concentrations in the bacterial extracellular polymeric substances (EPS) were significantly increased by iron supplementation. To clarify this mechanism, intracellular metabolomic analysis was carried out, showing that the differential, down-regulated metabolites included succinic acid. The addition of 1.7 mM succinic acid counteracted the biofilm-forming effect of iron, with no bactericidal side effects.

CONCLUSION: This study demonstrates the importance of succinic acid and iron in K. pneumoniae biofilms, and provides insight into the formation of K. pneumoniae biofilms and direction for the development of new antibacterial agents.}, } @article {pmid35409199, year = {2022}, author = {Li, QC and Wang, B and Zeng, YH and Cai, ZH and Zhou, J}, title = {The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment.}, journal = {International journal of molecular sciences}, volume = {23}, number = {7}, pages = {}, pmid = {35409199}, issn = {1422-0067}, support = {41976126//National Natural Science Foundation of China/ ; 2020B1515120012//Guangdong Basic and Applied Basic Research Foundation/ ; }, mesh = {*Biofilms ; *Biofouling/prevention & control ; Oxidants/pharmacology ; Pollen ; Seawater/microbiology ; }, abstract = {Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose−lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.}, } @article {pmid35408683, year = {2022}, author = {Neumann, N and Honke, M and Povydysh, M and Guenther, S and Schulze, C}, title = {Evaluating Tannins and Flavonoids from Traditionally Used Medicinal Plants with Biofilm Inhibitory Effects against MRGN E. coli.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {7}, pages = {}, pmid = {35408683}, issn = {1420-3049}, support = {393148499//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Escherichia coli ; Flavonoids/pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; *Plants, Medicinal ; Tannins/analysis/pharmacology ; }, abstract = {In the search for alternative treatment options for infections with multi-resistant germs, traditionally used medicinal plants are currently being examined more intensively. In this study, the antimicrobial and anti-biofilm activities of 14 herbal drugs were investigated. Nine of the tested drugs were traditionally used in Europe for treatment of local infections. For comparison, another five drugs monographed in the European Pharmacopoeia were used. Additionally, the total tannin and flavonoid contents of all tested drugs were analyzed. HPLC fingerprints were recorded to obtain further insights into the components of the extracts. The aim of the study was to identify herbal drugs that might be useable for treatment of infectious diseases, even with multidrug resistant E. coli, and to correlate the antimicrobial activity with the total content of tannins and flavonoids. The agar diffusion test and anti-biofilm assay were used to evaluate the antimicrobial potential of different extracts from the plants. Colorimetric methods (from European Pharmacopeia) were used for determination of total tannins and flavonoids. The direct antimicrobial activity of most of the tested extracts was low to moderate. The anti-biofilm activity was found to be down to 10 µg mL−1 for some extracts. Tannin contents between 2.2% and 10.4% of dry weight and total flavonoid contents between 0.1% and 1.6% were found. Correlation analysis indicates that the antimicrobial and the anti-biofilm activity is significantly (p < 0.05) dependent on tannin content, but not on flavonoid content. The data analysis revealed that tannin-rich herbal drugs inhibit pathogens in different ways. Thus, some of the tested herbal drugs might be useable for local infections with multi-resistant biofilm-forming pathogens. For some of the tested drugs, this is the first report about anti-biofilm activity, as well as total tannin and flavonoid content.}, } @article {pmid35407064, year = {2022}, author = {Roy, PK and Song, MG and Park, SY}, title = {Impact of Quercetin against Salmonella Typhimurium Biofilm Formation on Food-Contact Surfaces and Molecular Mechanism Pattern.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35407064}, issn = {2304-8158}, support = {2021R1I1A3A04037468//National Research Foundation of Korea/ ; }, abstract = {Quercetin is an active nutraceutical element that is found in a variety of foods, vegetables, fruits, and other products. Due to its antioxidant properties, quercetin is a flexible functional food that has broad protective effects against a wide range of infectious and degenerative disorders. As a result, research is required on food-contact surfaces (rubber (R) and hand gloves (HG)) that can lead to cross-contamination. In this investigation, the inhibitory effects of quercetin, an antioxidant and antibacterial molecule, were investigated at sub-MIC (125; 1/2, 62.5; 1/4, and 31.25; 1/8 MIC, μg/mL) against Salmonella Typhimurium on surfaces. When quercetin (0−125 μg/mL) was observed on R and HG surfaces, the inhibitory effects were 0.09−2.49 and 0.20−2.43 log CFU/cm2, respectively (p < 0.05). The results were confirmed by field emission scanning electron microscopy (FE-SEM), because quercetin inhibited the biofilms by disturbing cell-to-cell connections and inducing cell lysis, resulting in the loss of normal cell morphology, and the motility (swimming and swarming) was significantly different at 1/4 and 1/2 MIC compared to the control. Quercetin significantly (p < 0.05) suppressed the expression levels of virulence and stress response (rpoS, avrA, and hilA) and quorum-sensing (luxS) genes. Our findings imply that plant-derived quercetin could be used as an antibiofilm agent in the food industry to prevent S. Typhimurium biofilm formation.}, } @article {pmid35407047, year = {2022}, author = {Madani, A and Esfandiari, Z and Shoaei, P and Ataei, B}, title = {Evaluation of Virulence Factors, Antibiotic Resistance, and Biofilm Formation of Escherichia coli Isolated from Milk and Dairy Products in Isfahan, Iran.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35407047}, issn = {2304-8158}, abstract = {Diarrheagenic E. coli (DEC) strains are important causes of gastrointestinal diseases worldwide, especially in developing countries. This study aimed to investigate the presence, antibiotic resistance, and potential biofilm formation in dairy products in Isfahan, Iran. A total of 200 samples, including traditional and pasteurized dairy products, were analyzed. In 200 samples, 54 E. coli isolates, including (48/110) and (6/90) positive samples of traditional and pasteurized dairy products, were detected. Furthermore, pathogenic strains were isolated from 30% of traditional dairy products and 5.55% of pasteurized dairy products. Most isolates were classified as enteropathogenic E. coli (EPEC). Moreover, antibiotic resistance was evaluated using the disk diffusion method for pathogenic E. coli. Overall, 73.68% of contaminated samples by pathogenic strains were resistant to at least one antibiotic. The highest resistance was observed against streptomycin (57.9%), followed by tetracycline (50%). Additionally, all isolates were sensitive to amikacin. For evaluating biofilm formation, the violet crystal assay was applied on a polystyrene microplate well for pathogenic isolates. In total, 68.42% of isolates were able to form biofilms. The presence of E. coli in dairy products indicates potential health risks for Iranian consumers. Serious measures are needed to control and prevent the spread of this pathogen.}, } @article {pmid35406987, year = {2022}, author = {Ibacache-Quiroga, C and González-Pizarro, K and Charifeh, M and Canales, C and Díaz-Viciedo, R and Schmachtenberg, O and Dinamarca, MA}, title = {Metagenomic and Functional Characterization of Two Chilean Kefir Beverages Reveals a Dairy Beverage Containing Active Enzymes, Short-Chain Fatty Acids, Microbial β-Amyloids, and Bio-Film Inhibitors.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {35406987}, issn = {2304-8158}, support = {PAI79140114//Agencia Nacional de Investigación y Desarrollo/ ; FONDEF VIUE170112//Agencia Nacional de Investigación y Desarrollo/ ; DIUV-CIDI 4/2016//Universidad de Valparaíso/ ; }, abstract = {Kefir beverage is a probiotic food associated with health benefits, containing probiotic microorganisms and biomolecules produced during fermentation. The microbial composition of these beverages varies among countries, geographical regions, and the substrates, therefore, the characterization of kefir beverages is of great relevance in understanding their potential health-promoting and biotechnological applications. Therefore, this study presents the metagenomic and functional characterization of two Chilean kefir beverages, K02 and K03, through shotgun and amplicon-based metagenomic, microbiological, chemical, and biochemical studies. Results show that both beverages’ microbiota were mainly formed by Bacteria (>98%), while Eukarya represented less than 2%. Regarding Bacteria, the most abundant genera were Acetobacter (93.43% in K02 and 80.99% in K03) and Lactobacillus (5.72% in K02 and 16.75% in K03), while Kazachstania was the most abundant genus from Eukarya (42.55% and 36.08% in K02 and K03). Metagenomic analyses revealed metabolic pathways for lactose and casein assimilation, biosynthesis of health-promoting biomolecules, and clusters for antibiotic resistance, quorum sensing communication, and biofilm formation. Enzymatic activities, microbial β-amyloids, and short-chain fatty acids (acetic acid and propionic acid) were also detected in these beverages. Likewise, both kefir beverages inhibited biofilm formation of the opportunistic pathogen Pseudomonas aeruginosa.}, } @article {pmid35406207, year = {2022}, author = {Josic, U and Mazzitelli, C and Maravic, T and Fidler, A and Breschi, L and Mazzoni, A}, title = {Biofilm in Endodontics: In Vitro Cultivation Possibilities, Sonic-, Ultrasonic- and Laser-Assisted Removal Techniques and Evaluation of the Cleaning Efficacy.}, journal = {Polymers}, volume = {14}, number = {7}, pages = {}, pmid = {35406207}, issn = {2073-4360}, abstract = {Incomplete and inadequate removal of endodontic biofilm during root canal treatment often leads to the clinical failure. Over the past decade, biofilm eradication techniques, such as sonication of irrigant solutions, ultrasonic and laser devices have been investigated in laboratory settings. This review aimed to give an overview of endodontic biofilm cultivation methods described in papers which investigated sonic-, ultrasonic- and Er:Yag laser-assisted biofilm removal techniques. Furthermore, the effectiveness of these removal techniques was discussed, as well as methods used for the evaluation of the cleaning efficacy. In general, laser assisted agitation, as well as ultrasonic and sonic activation of the irrigants provide a more efficient biofilm removal compared to conventional irrigation conducted by syringe/needle. The choice of irrigant is an important factor for reducing the bacterial contamination inside the root canal, with water and saline being the least effective. Due to heterogeneity in methods among the reviewed studies, it is difficult to compare sonic-, ultrasonic- and Er:Yag laser-assisted techniques among each other and give recommendations for the most efficient method in biofilm removal. Future studies should standardize the methodology regarding biofilm cultivation and cleaning methods, root canals with complex morphology should be introduced in research, with the aim of simulating the clinical scenario more closely.}, } @article {pmid35405293, year = {2022}, author = {de Melo Costa, D and Castillo, R and Vickery, K and Ferreira Veiga Tipple, A and de Oliveira Lopes, LK and Hu, H}, title = {Hinged surgical instruments: efficacy of double manual cleaning versus automated cleaning on biofilm removal.}, journal = {The Journal of hospital infection}, volume = {124}, number = {}, pages = {67-71}, doi = {10.1016/j.jhin.2022.03.011}, pmid = {35405293}, issn = {1532-2939}, mesh = {Biofilms ; *Decontamination ; *Detergents ; Humans ; Surgical Instruments/microbiology ; }, abstract = {The efficacy of double manual cleaning (DMC) with enzymatic detergent followed by alkaline detergent on biofilm removal on hinged surgical instruments was compared to automated cleaning. Biofilm-covered haemostatic forceps were divided into four groups: positive control (soaked in sterile water); DMC; DMC plus extra brushing of the inner hinge; and automated cleaning. All DMC, DMC plus brushing the hinge, and automated cleaning significantly (P < 0.001) reduced 94.8%, 99.8%, and 100% viable bacteria and 82.3%, 93.8%, and 95.1% residual protein, respectively, compared to positive control. DMC instruments had significantly more viable bacteria (P < 0.05) and residual protein (P < 0.01) than those in instruments subjected to DMC with hinge brushing and automated cleaning. However, there was no significant difference in residual protein between DMC with hinge brushing and automated cleaning. In sterilizing service units with no access to automated cleaning equipment, it is important to brush the inner hinge during manual cleaning, and DMC plus brushing the inner hinge could be considered a viable alternative for cleaning hinged surgical instruments.}, } @article {pmid35405192, year = {2022}, author = {Chyoshi, B and Gomes Coelho, LH and García, J and Subtil, EL}, title = {Fate and removal of emerging contaminants in anaerobic fluidized membrane bioreactor filled with thermoplastic gel as biofilm support.}, journal = {Chemosphere}, volume = {300}, number = {}, pages = {134557}, doi = {10.1016/j.chemosphere.2022.134557}, pmid = {35405192}, issn = {1879-1298}, mesh = {Amoxicillin ; Anaerobiosis ; Biofilms ; Bioreactors ; *Diclofenac ; Estradiol/analysis ; Sewage ; Waste Disposal, Fluid/methods ; *Water Pollutants, Chemical/analysis ; }, abstract = {The Anaerobic Fluidized Membrane Bioreactor (AnFMBR) is a membrane-based hybrid technology that can overcome the limitations of conventional anaerobic sewage treatment. Although previous studies have demonstrated excellent performance in the removal of conventional organic pollutants, further research into the removal paths of emerging contaminants (ECs) under various operating conditions is required for proper design and development of the AnFMBR technology. Regarding this, the fate of four ECs in a lab-scale AnFMBR filled with thermoplastic gel for biofilm growth was investigated under various Hydraulic Retention Time (HRT) conditions. When the HRT was 13 h, diclofenac and 17β-estradiol were efficiently removed at 93% and 72% respectively. Even after an HRT reduction to 6.5 h, the system was still able to maintain high ECs removals (74% for diclofenac and 69% for 17β-estradiol). However, irrespective of HRT operational condition, smaller removals of 17a-ethinylestradiol (37-52%) were observed, while only marginal removals of amoxicillin were achieved (5-29%). Biotransformation was attributed as the main route for ECs removal. The results obtained in this study indicate that the membrane-based hybrid AnFMBR can be used to treat the target ECs without influence on anaerobic process. The technology had better removal efficiency for diclofenac and 17β-estradiol. However, the AnFMBR system exhibits high variability in EC removal and low capacity for amoxicillin removal, implying that a combination of other processes is still required to properly avoid the release of these contaminants into the environment.}, } @article {pmid35402433, year = {2022}, author = {Roy, S and Chowdhury, G and Mukhopadhyay, AK and Dutta, S and Basu, S}, title = {Convergence of Biofilm Formation and Antibiotic Resistance in Acinetobacter baumannii Infection.}, journal = {Frontiers in medicine}, volume = {9}, number = {}, pages = {793615}, pmid = {35402433}, issn = {2296-858X}, abstract = {Acinetobacter baumannii (A. baumannii) is a leading cause of nosocomial infections as this pathogen has certain attributes that facilitate the subversion of natural defenses of the human body. A. baumannii acquires antibiotic resistance determinants easily and can thrive on both biotic and abiotic surfaces. Different resistance mechanisms or determinants, both transmissible and non-transmissible, have aided in this victory over antibiotics. In addition, the propensity to form biofilms (communities of organism attached to a surface) allows the organism to persist in hospitals on various medical surfaces (cardiac valves, artificial joints, catheters, endotracheal tubes, and ventilators) and also evade antibiotics simply by shielding the bacteria and increasing its ability to acquire foreign genetic material through lateral gene transfer. The biofilm formation rate in A. baumannii is higher than in other species. Recent research has shown how A. baumannii biofilm-forming capacity exerts its effect on resistance phenotypes, development of resistome, and dissemination of resistance genes within biofilms by conjugation or transformation, thereby making biofilm a hotspot for genetic exchange. Various genes control the formation of A. baumannii biofilms and a beneficial relationship between biofilm formation and "antimicrobial resistance" (AMR) exists in the organism. This review discusses these various attributes of the organism that act independently or synergistically to cause hospital infections. Evolution of AMR in A. baumannii, resistance mechanisms including both transmissible (hydrolyzing enzymes) and non-transmissible (efflux pumps and chromosomal mutations) are presented. Intrinsic factors [biofilm-associated protein, outer membrane protein A, chaperon-usher pilus, iron uptake mechanism, poly-β-(1, 6)-N-acetyl glucosamine, BfmS/BfmR two-component system, PER-1, quorum sensing] involved in biofilm production, extrinsic factors (surface property, growth temperature, growth medium) associated with the process, the impact of biofilms on high antimicrobial tolerance and regulation of the process, gene transfer within the biofilm, are elaborated. The infections associated with colonization of A. baumannii on medical devices are discussed. Each important device-related infection is dealt with and both adult and pediatric studies are separately mentioned. Furthermore, the strategies of preventing A. baumannii biofilms with antibiotic combinations, quorum sensing quenchers, natural products, efflux pump inhibitors, antimicrobial peptides, nanoparticles, and phage therapy are enumerated.}, } @article {pmid35402304, year = {2022}, author = {Krzyżek, P and Migdał, P and Grande, R and Gościniak, G}, title = {Biofilm Formation of Helicobacter pylori in Both Static and Microfluidic Conditions Is Associated With Resistance to Clarithromycin.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {868905}, pmid = {35402304}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Clarithromycin/pharmacology ; Drug Resistance, Bacterial ; *Helicobacter Infections/drug therapy ; *Helicobacter pylori/genetics ; Humans ; Levofloxacin/pharmacology ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; Microfluidics ; }, abstract = {It is widely accepted that production of biofilm is a protective mechanism against various type of stressors, including exposure to antibiotics. However, the impact of this structure on the spread of antibiotic resistance in Helicobacter pylori is still poorly understood. Therefore, the aim of the current research was to determine the relationship between biofilm formation and antibiotic resistance of H. pylori. The study was carried out on 24 clinical strains with different resistance profiles (antibiotic-sensitive, mono-resistant, double-resistant and multidrug-resistant) against clarithromycin (CLR), metronidazole (MTZ) and levofloxacin (LEV). Using static conditions and a crystal violet staining method, a strong correlation was observed between biofilm formation and resistance to CLR but not MTZ or LEV. Based on the obtained results, three the strongest and three the weakest biofilm producers were selected and directed for a set of microfluidic experiments performed in the Bioflux system combined with fluorescence microscopy. Under continuous flow conditions, it was observed that strong biofilm producers formed twice as much of biofilm and created significantly more eDNA and in particular proteins within the biofilm matrix when compared to weak biofilm producers. Additionally, it was noticed that strong biofilm producers had higher tendency for autoaggregation and presented morphostructural differences (a greater cellular packing, shorter cells and a higher amount of both OMVs and flagella) in relation to weak biofilm counterparts. In conclusion, resistance to CLR in clinical H. pylori strains was associated with a broad array of phenotypical features translating to the ability of strong biofilm formation.}, } @article {pmid35400968, year = {2022}, author = {Mitsuwan, W and Sornsenee, P and Romyasamit, C}, title = {Lacticaseibacillus spp.; Probiotic candidates from Palmyra palm sugar possesses antimicrobial and anti-biofilm activities against methicillin-resistant Staphylococcus aureus.}, journal = {Veterinary world}, volume = {15}, number = {2}, pages = {299-308}, pmid = {35400968}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Probiotics are beneficial microorganisms that play important roles by adhering to the gut and producing antimicrobial substances to inhibit pathogens. The objective of this study was to isolate and characterize the probiotic lactic acid bacteria (LAB) from Palmyra palm sugar, which can produce antimicrobial compounds against methicillin-resistant Staphylococcus aureus (MRSA), a new zoonotic and food-borne pathogens.

MATERIALS AND METHODS: Twenty-six LAB isolates were isolated from 30 Palmyra palm sugar samples. Three selected LAB were further characterized as probiotics. In addition, the antibacterial and anti-biofilm-forming activities of the probiotics' culture supernatants against MRSA and food-borne pathogens were investigated. Finally, the selected probiotics were identified by aligning 16S rRNA sequences.

RESULTS: The three confirmed probiotics, WU 0904, WU 2302, and WU 2503, showed strong antibacterial activities against S. aureus, MRSA, Escherichia coli O157:H7, and Listeria monocytogenes, as measured by a broth microdilution assay. Among the LAB isolates, 82.22-86.58%, 91.83-96.06%, and 64.35-74.93% exhibited resistance to low pH, pancreatin treatment, and bile salts, respectively. It was found that 59.46% and 83.33% auto-aggregation was observed in 2 and 24 h, respectively. Moreover, 50.25-57.24% adhesion was detected after the incubation of the bacterial cells to Caco-2 cells.. Biofilm inhibition (82.81-87.24%) was detected after the treatment of MRSA with the culture supernatants, when compared with that to the control. By the alignment of 16S rRNA sequences, the isolate WU 2302 was identified as Lacticaseibacillus spp. with 98.82% homology when compared to the GenBank database.

CONCLUSION: This study indicates that isolated probiotics can produce antimicrobial compounds against MRSA and food-borne pathogens. The obtained results strongly suggest that these probiotics are promising candidates for pharmaceutical products.}, } @article {pmid35400420, year = {2022}, author = {Sun, J and Huang, L and Sun, Z and Wang, D and Liu, F and Du, L and Wang, D}, title = {Combination of ultrasound and chlorogenic acid for inactivation of planktonic and biofilm cells of Pseudomonas fluorescens.}, journal = {Food research international (Ottawa, Ont.)}, volume = {155}, number = {}, pages = {111009}, doi = {10.1016/j.foodres.2022.111009}, pmid = {35400420}, issn = {1873-7145}, mesh = {Biofilms ; Chlorogenic Acid/pharmacology ; Microscopy, Electron, Scanning ; Plankton ; *Pseudomonas fluorescens ; }, abstract = {This study investigated the synergistic efficacy of ultrasound (US, 50 kHz, 400 W) in combination with chlorogenic acid (CA; 0, 0.5, 1, and 2%) to inactivate Pseudomonas fluorescens planktonic and biofilm cells. The P. fluorescens planktonic and biofilm cells were treated with CA with and without US for 5, 10, 20, 30, or 60 min. Results showed that US enhanced the efficacy of CA for inactivation of both P. fluorescens planktonic and biofilm cells. Treatment with 2% CA and US could completely inactivate P. fluorescens planktonic cells within 10 min and the biofilm cells within 30 min. Confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), ATP, and nucleic acid release assays indicated that the combination of US and CA could quickly damage the integrity of P. fluorescens planktonic and biofilm cell membranes. The combined treatment effectively inactivates P. fluorescens planktonic and biofilm cells via the synergetic destruction of the biofilm structure and bacterial cell integrity.}, } @article {pmid35399651, year = {2022}, author = {Prabu, R and Mohanty, A and Balakrishnan, SS and Jayalakshmi, G and Sundar, K}, title = {Molecular docking and simulation of IcaC protein as O-succinyltransferase function in staphylococcus epidermidis biofilm formation.}, journal = {Current research in structural biology}, volume = {4}, number = {}, pages = {78-86}, pmid = {35399651}, issn = {2665-928X}, abstract = {Intercellular adhesion (IcaADBC) operon is necessary for PNAG (Polyβ-1,6-N-acetyl-D-glucosamine) biosynthesis of biofilm formation in Staphylococcus epidermidis. IcaC protein has a wide range of functions in terms of growth phase variation, migration, transposon insertion, PNAG modification, biofilm formation. Unusual TTTA signature motifs were identified from nucleotide sequence. Asparagine-linked glycosylation consensus motifs were identified at position 169 and 240. S. epidermidis was a close evolutionary association with S. haemolyticus and other Staphylococcus spp. Due to the non-availability of crystal structure, protein threading procedure was selected for constructing a full length IcaC three-dimensional structure. QMEANBrane structure quality assessment with model scores -100000 range within predicted integral membrane structure. IcaC motif constitutes 18 transmembrane helix, 37 helix-helix interaction, 8 beta turn, 2 gamma turn. Binding free energy was calculated with their succinate ligand docking form hydrogen bond with critical amino acids showed ΔG score -2.574 kJ/mol using Schrödinger. Serine (Ser96), Glutamic acid (Glu99), Tryptophan (Trp191) were active site amino acids form the catalytic core required for O-succinyltransferase function. Molecular dynamics simulation (MDS) was performed to evaluate the stability of IcaC protein and IcaC-Succinate binding complexes with the active site amino acids throughout trajectories captured with time scale 100 ns simulation period using GROMACS 4.5.}, } @article {pmid35398923, year = {2022}, author = {Rodrigues, DS and Lannes-Costa, PS and Santos, GS and Ribeiro, RL and Langoni, H and Teixeira, LM and Nagao, PE}, title = {Antimicrobial resistance, biofilm production and invasion of mammary epithelial cells by Enterococcus faecalis and Enterococcus mundtii strains isolated from bovine subclinical mastitis in Brazil.}, journal = {Letters in applied microbiology}, volume = {75}, number = {2}, pages = {184-194}, doi = {10.1111/lam.13718}, pmid = {35398923}, issn = {1472-765X}, support = {//Sub-Reitoria de Pós-Graduação e Pesquisa da Universidade do Estado do Rio de Janeiro (SR-2/UERJ)/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Brazil/epidemiology ; Cattle ; Drug Resistance, Bacterial ; Enterococcus ; Enterococcus faecalis ; Epithelial Cells ; Female ; Humans ; *Mastitis, Bovine/microbiology ; Microbial Sensitivity Tests ; }, abstract = {Members of the genus Enterococcus are among the most relevant etiologic agents of bovine clinical and subclinical mastitis, a major problem for the dairy industry. In Brazil, clonal diversity, and multidrug resistance profiles related to bovine infections need further investigation. In this study, 11 bacterial strains recovered from mastitis subclinical cases detected in different farms of São Paulo, Brazil, were identified as Enterococcus faecalis (n = 8) and Enterococcus mundtii (n = 3) by biochemical testing and MALDI-TOF mass spectrometry. Pulsed-field gel electrophoresis categorized the enterococcal isolates into two main clusters (A and B) with similarity ranging from 85 to 100%. The isolates were shown to be resistant tetracycline (73%), erythromycin (73%), quinupristin-dalphopristin (64%), norfloxacin (9%), fosfomycin (9%) and linezolid (9%). Moreover, seven strains (64%) were considered multidrug-resistant. All the isolates were able to produce biofilms when grown in milk for 24 h: 54·54% were classified as moderate producers and 45·45% were weak producers. Interestingly, only two strains (Ef17 and Em42) remained as moderate biofilm producers after 48 h incubation. Moreover, all isolates showed no ability to form biofilm in tryptic soy broth (TSB) after 24 and 48 h incubation. In addition, cytoskeleton components were partially involved in E. faecalis and E. mundtii entry to epithelial cells as demonstrated by induction of actin stress fibre. In conclusion, enterococci isolates recovered from bovine subclinical mastitis were resistant to several classes of antibiotics, showing the ability to form biofilms in milk and invade mammary epithelial cells, suggesting an advantageous feature in mammary gland colonization during mastitis development. In addition, they can spread along the food chain by different routes and eventually constitute a possible threat for public health, including E. mundtii specie.}, } @article {pmid35398730, year = {2022}, author = {Huan, X and Wang, Y and Peng, X and Xie, S and He, Q and Zhang, X and Lan, L and Yang, C}, title = {Design, synthesis, and biological evaluations of substituted pyrazoles as pyrrolomycin analogues against staphylococcal biofilm.}, journal = {European journal of medicinal chemistry}, volume = {236}, number = {}, pages = {114309}, doi = {10.1016/j.ejmech.2022.114309}, pmid = {35398730}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Pyrazoles/pharmacology ; *Staphylococcal Infections ; Staphylococcus ; Staphylococcus aureus ; }, abstract = {The formation of biofilm enables Staphylococcus aureus to resist antibiotics and causes chronic infections. Several compounds of pyrrolomycins are potent antibacterial agents which display inhibition upon staphylococcal biofilms. We designed and synthesized two series of substituted pyrazoles as pyrrolomycin analogues. Compounds 17a, 17d and 17h displayed potent antibacterial activity against various vancomycin-resistant Enterococcus faecalis (VRE) and methicillin-resistant Staphylococcus aureus (MRSA), and 17d showed the most potent activity against MRSA (MIC = 0.0625 μg/mL), vancomycin-intermediate Staphylococcus aureus (VISA) (MIC = 0.0313 μg/mL). Further study indicated that compound 17h could significantly reduce the biofilm formation of MRSA and exhibited promising selectivity. In vitro liver microsomal stability was also evaluated and the results manifested that 17h was metabolically stable in human liver microsomes.}, } @article {pmid35398435, year = {2022}, author = {Hou, J and Shao, G and Adyel, TM and Li, C and Liu, Z and Liu, S and Miao, L}, title = {Can the carbon metabolic activity of biofilm be regulated by the hydrodynamic conditions in urban rivers?.}, journal = {The Science of the total environment}, volume = {832}, number = {}, pages = {155082}, doi = {10.1016/j.scitotenv.2022.155082}, pmid = {35398435}, issn = {1879-1026}, mesh = {Biofilms ; Carbon ; *Hydrodynamics ; *Rivers ; Stress, Mechanical ; }, abstract = {Hydrodynamic regulation is widely used to improve the water quality of urban rivers. However, it is yet to explore substantially whether hydrodynamics could regulate the metabolic activity of biofilm in such aquatic systems. Herein, the pilot experiment of hydrodynamics in the rotation tanks was designed, including two experiment phases, namely constant flow and adjusting flow for 21 days and 14 days, respectively. In constant flow phase, biofilms grew in five shear stress gradients (R1-R5, 0.0044- 0.12 Pa). The carbon metabolic rate (k) of mature biofilms evaluated by BIOLOG ECO microplates showed a hump-shaped relationship with increasing shear stress, with R3 (0.049 Pa) the highest, while R5 (0.12 Pa) the lowest. To verify whether the metabolic activity of biofilm cultured at constant flow phase can be regulated by shear stress, we initiated the adjusting flow phase, and shear stress in reactors was reset uniformly at 0.049 Pa (with the highest k). Results showed the carbon metabolic activity of biofilm in reactor R4 and R5 increased rapidly by day 3, and there was no significant difference between the carbon metabolic rates among the five treatments by day 14. Meanwhile, the utilization levels of polymers and carbohydrates by biofilms were significantly different among the five treatments after hydrodynamic regulations. These results suggested that the total carbon metabolic activity of biofilm can be regulated by hydrodynamics, while the divergent changes of the specific carbon source category might affect the biofilm-mediated carbon biogeochemical processes, which should be considered for the application of hydrodynamic regulation in river ecological restoration projects.}, } @article {pmid35398128, year = {2022}, author = {Lu, B and Jiang, C and Chen, Z and Li, A and Wang, W and Zhang, S and Luo, G}, title = {Fate of polylactic acid microplastics during anaerobic digestion of kitchen waste: Insights on property changes, released dissolved organic matters, and biofilm formation.}, journal = {The Science of the total environment}, volume = {834}, number = {}, pages = {155108}, doi = {10.1016/j.scitotenv.2022.155108}, pmid = {35398128}, issn = {1879-1026}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Dissolved Organic Matter ; Methane/metabolism ; Microplastics ; *Plastics/metabolism ; Polyesters/metabolism ; Sewage ; }, abstract = {Polylactic acid (PLA), an alternative to petroleum-based plastics, has been widely used in food packaging and disposable tableware for biodegradable properties. As a result, PLA fragments were often mixed with kitchen waste (KW) and disposed of together. This study aimed to assess the fate of polylactic acid microplastics (PMP) when co-digested with KW. The spiked PMP did not increase the methane yield of KW but had deformation and fragmentation at mesophilic and thermophilic conditions, respectively. Identification of physicochemical properties and leachates showed that the anaerobic digestion of the KW process caused the aging and fragmentation of PMP, including the generation of irregular cracking and tiny daughter particles, the increase of oxygen-containing functional groups, and the releasing of dissolved organic matters (DOM). The thermophilic anaerobic digestion with KW enhanced the aging and fragmentation of PMP to the highest degree, which was attributed to the high temperature and enriched microorganisms (Peptococcaceae, Tepidimicrobium, and Clostridium_sensu_stricto_7) in the biofilm. Clostridium_sensu_stricto_7 was only found in the anaerobic digestion with KW, which meant the KW anaerobic digestion could contribute to the enrichment of microorganisms that promoted the PMP degradation.}, } @article {pmid35397438, year = {2022}, author = {Li, Z and Huang, L and Hao, W and Yang, J and Qian, H and Zhang, D}, title = {Accelerating effect of pyocyanin on microbiologically influenced corrosion of 304 stainless steel by the Pseudomonas aeruginosa biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {146}, number = {}, pages = {108130}, doi = {10.1016/j.bioelechem.2022.108130}, pmid = {35397438}, issn = {1878-562X}, mesh = {Biofilms ; Corrosion ; *Pseudomonas aeruginosa/metabolism ; Pyocyanine/metabolism ; *Stainless Steel/chemistry ; Steel ; }, abstract = {In this study, the influence of exogenous pyocyanin (PYO) on the microbiologically influenced corrosion (MIC) of 304 stainless steel by Pseudomonas aeruginosa was investigated. Under sterile condition, the additional PYO in the culture medium had no effect on the corrosion of 304 stainless steel. In contrast, P. aeruginosa biofilm inoculated in the media with additional PYO resulted in more severe pitting corrosion. EIS and cyclic potentiodynamic polarization results indicated that exogenous PYO promoted the electron transfer efficiency between the P. aeruginosa biofilm and the stainless steel surface. X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) results further demonstrated that the P. aeruginosa led the breakdown of passive film predominantly by accelerating the bioreductive dissolution of iron oxides.}, } @article {pmid35396841, year = {2022}, author = {Zaidi, A}, title = {Correction to: Biofilm development in L. fermentum under shear flow & sequential GIT digestion.}, journal = {FEMS microbiology letters}, volume = {369}, number = {1}, pages = {}, doi = {10.1093/femsle/fnac027}, pmid = {35396841}, issn = {1574-6968}, } @article {pmid35396139, year = {2022}, author = {Barnier, C and Clerissi, C and Lami, R and Intertaglia, L and Lebaron, P and Grimaud, R and Urios, L}, title = {Corrigendum to "Description of Palleronia rufa sp. nov., a biofilm-forming and AHL-producing Rhodobacteraceae, reclassification of Hwanghaeicola aestuarii as Palleronia aestuarii comb. nov., Maribius pontilimi as Palleronia pontilimi comb. nov., Maribius salinus as Palleronia salina comb. nov., Maribius pelagius as Palleronia pelagia comb. nov. and emended description of the genus Palleronia" [Syst. Appl. Microbiol. 43 (1) (2020) 126018].}, journal = {Systematic and applied microbiology}, volume = {45}, number = {5}, pages = {126321}, doi = {10.1016/j.syapm.2022.126321}, pmid = {35396139}, issn = {1618-0984}, } @article {pmid35395437, year = {2022}, author = {Karbysheva, S and Cabric, S and Koliszak, A and Bervar, M and Kirschbaum, S and Hardt, S and Perka, C and Trampuz, A}, title = {Clinical evaluation of dithiothreitol in comparison with sonication for biofilm dislodgement in the microbiological diagnosis of periprosthetic joint infection.}, journal = {Diagnostic microbiology and infectious disease}, volume = {103}, number = {2}, pages = {115679}, doi = {10.1016/j.diagmicrobio.2022.115679}, pmid = {35395437}, issn = {1879-0070}, mesh = {*Arthritis, Infectious/diagnosis ; Biofilms ; Dithiothreitol ; Humans ; Prospective Studies ; *Prosthesis-Related Infections/diagnosis/microbiology ; Sensitivity and Specificity ; Sonication ; }, abstract = {Sonication of explanted devices is well investigated method and was shown to improve the microbiological diagnosis of impant-associated infections by physical removal of bacterial biofilms. Recently, novel approach with chemical agents have been investigated for biofilm dislodgement such as dithiothreitol (DTT). We compared the biofilm dislodgement efficacy of chemical method (dithiothreitol, DTT) compared to the sonication procedure in the diagnosis of prosthetic joint infections (PJI). In a prospective cohort, 187 patients undergoing hip and knee prostheses explantation were included, of whom 94 were assigned for sonication and 93 for DTT group. Sonication showed better sensitivity (73.8%) than DTT (43.2%) for the diagnosis of PJI and comparable specificity (98% and 94.6%, respectively). We concluded that sonication provides a more reliable diagnosis of PJI and detects about 30% more pathogens compared to DTT system. The study was registered at ClinicalTrials.gov (NCT02530229).}, } @article {pmid35395366, year = {2022}, author = {Gao, D and Li, Y and Liang, H}, title = {Biofilm carriers for anaerobic ammonium oxidation: Mechanisms, applications, and roles in mainstream systems.}, journal = {Bioresource technology}, volume = {353}, number = {}, pages = {127115}, doi = {10.1016/j.biortech.2022.127115}, pmid = {35395366}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Nitrogen ; Oxidation-Reduction ; Sewage/microbiology ; }, abstract = {The anaerobic ammonium oxidation (ANAMMOX) process was proposed as the most promising nitrogen removal process. Biofilm carriers were demonstrated to effectively enhance the anaerobic ammonium oxidating bacteria (AnAOB) retention. This paper reviews the effect of carrier properties on the AnAOB biofilm development according to the biofilm development process and the application state-of-art of three major kinds of conventional carriers, organic-based, inorganic-based carriers, and gel carriers, from the view of system performance and functional microorganisms. The carrier modification methods and purpose are thoroughly summarized and classified into three categories corresponding to various carrier defects. Four important aspects of the desirable carrier for the mainstream ANAMMOX process were proposed, including providing spatial configuration, enhancing the biomass retention, reinforcing the activity, and improving the growth environment, which needs to combine the advantages of organic and inorganic materials. Eventually, the future application directions of novel carriers for the ANAMMOX-based process were also highlighted.}, } @article {pmid35395308, year = {2022}, author = {Zhou, Y and Anwar, MN and Guo, B and Huang, W and Liu, Y}, title = {Response of antibiotic resistance genes and microbial niches to dissolved oxygen in an oxygen-based membrane biofilm reactor during greywater treatment.}, journal = {The Science of the total environment}, volume = {833}, number = {}, pages = {155062}, doi = {10.1016/j.scitotenv.2022.155062}, pmid = {35395308}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Bioreactors/microbiology ; Drug Resistance, Microbial/genetics ; Nitrogen/analysis ; *Oxygen ; *Waste Disposal, Fluid ; }, abstract = {Linear alkylbenzene sulfonates (LAS) in greywater (GW) will simulate antibiotic resistance genes (ARGs) production in the biofilm-based system. Our study emphasizes the dissolved oxygen (DO)-dependent ARGs accumulation and microbial niches succession in an oxygen-based membrane biofilm reactor (O2-MBfR) treating GW, as well as revealing the key roles of EPS. Changing DO concentrations led to significant differences in ARGs production, EPS secretion and microbial communities, as well as the organics and nitrogen removal efficiency. Increasing DO concentration from 0.2 to 0.4 mg/L led to improved organics (> 90%) and nitrogen removal, as well as less EPS (especially for proteins and carbohydrates) and ARGs accumulation (e.g., intI-1, korB and sul-2) in the biofilm; the high-DO-concentration accumulated microbial niches, including Flavobacteriaceae and Cyanobacteria that revealed by LEfSe analysis, contributed to both nitrogen reduction and organics biodegradation. While, the inefficient electron acceptor at low DO conditions (0.2 mg/L) reduced the organics and nitrogen removal efficiency, as well as the improved accumulation of EPS in biofilm; high EPS enabled the capture of residual LAS from the liquid phase, which stimulated the production of ARGs by the distinct microbial community compositions. These findings suggested the DO-based ARGs reduction regulation strategy in the O2-MBfR treating GW.}, } @article {pmid35394280, year = {2022}, author = {Chen, H and Cheng, J and Cai, X and Han, J and Chen, X and You, L and Xiong, C and Wang, S}, title = {pH-Switchable Antimicrobial Supramolecular Hydrogels for Synergistically Eliminating Biofilm and Promoting Wound Healing.}, journal = {ACS applied materials & interfaces}, volume = {14}, number = {16}, pages = {18120-18132}, doi = {10.1021/acsami.2c00580}, pmid = {35394280}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Humans ; Hydrogels/chemistry/pharmacology ; Hydrogen-Ion Concentration ; Wound Healing ; *Wound Infection/drug therapy ; }, abstract = {Biofilm infection will cause chronic inflammation and hinder the normal healing process of wound. Here, based on the self-assembly of three designed amphiphilic pentapeptides named EK, GG, and DR, pH-switchable antibacterial hydrogels with amphiphilic fiber network are used for the eradication of biofilms and the rescue of delayed healing in infected wounds. These pentapeptides-based hydrogels exhibit an acidic pH-switchable antimicrobial effect and are biocompatible at neutral pH. Additionally, supramolecular nanofiber networks with physical cross-linking with thermosensitive polymers (PNIPAm) and loaded antibacterial oregano oil are further developed. In vitro experiments indicate that the antimicrobial activity of hydrogels comes from the disassembly of acidic pH-dependent nanofiber network and activated release of pentapeptides and oregano oil, which achieves synergistic biofilm eradication. Remarkably, DR-based supramolecular hydrogel improves the healing efficiency of the full-thickness wound of skin in vivo, which is manifested by increased wound closure rate, reduced inflammatory response, faster angiogenesis, and collagen deposition in the wound, exhibiting great potential as wound dressing. The proposed synergistic strategy of inhibiting biofilm formation and activating healing may provide an efficient method for the treatment of clinically infected wounds.}, } @article {pmid35393828, year = {2022}, author = {Zheng, XW and Qin, JF and Wang, XJ and Chen, HC and Zhu, ZJ and Chen, ZG}, title = {[Promoting Nitrogen Removal in ANAMMOX Biofilm Reactor by Fe[2+] Under Low Nitrogen Concentration].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {43}, number = {4}, pages = {2047-2054}, doi = {10.13227/j.hjkx.202107071}, pmid = {35393828}, issn = {0250-3301}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Extracellular Polymeric Substance Matrix/chemistry ; *Nitrogen/analysis ; Oxidation-Reduction ; Sewage ; Wastewater ; }, abstract = {The feasibility for nitrogen removal in a two-stage ANAMMOX biofilm reactor promoted by Fe[2+] under low nitrogen concentration was investigated. The results showed that the ANAMMOX reaction could be effectively promoted by a ρ(Fe[2+]) of 5, 10, and 15 mg·L[-1]. A ρ(Fe[2+]) of 10 mg·L[-1] presented the highest promotion for the ANAMMOX reaction, with the highest nitrogen removal efficiency (NRE) of 81.71% under a ρ(TN) of 150 mg·L[-1]and a nitrogen loading rate (NLR) of 0.62 kg·(m[3]·d)[-1]. Fe[2+] promoted the secretion of extracellular polymeric substance (EPS) and the synthesis of heme c in the ANAMMOX system. Batch test results further verified the positive effects by Fe[2+]on the activity of anaerobic ammonium oxidizing bacteria (AnAOB). The specific ANAMMOX activity (SAA) of 10 mg·L[-1] ρ(Fe[2+]) was 3.6 times as high as that of the control group[ρ(Fe[2+])=0 mg·L[-1]], whereas the activity of AnAOB was significantly inhibited with ρ(Fe[2+]) increased to 20 mg·L[-1]. High-throughput sequencing results showed that the addition of Fe[2+] increased the abundance of Candidatus_Kuenenia. When ρ(Fe[2+]) was 10 mg·L[-1], the relative abundance of Candidatus_Kuenenia in reactor 1 and reactor 2 increased to 16.18% and 4.22%, respectively. The stable operation of the two-stage ANAMMOX biofilm process promoted by Fe[2+]provides an alternative technology for low-strength nitrogen wastewater.}, } @article {pmid35393459, year = {2022}, author = {Belleville, P and Merlin, G and Ramousse, J and Deseure, J}, title = {Characterization of spatiotemporal electroactive anodic biofilm activity distribution using 1D simulations.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {5849}, pmid = {35393459}, issn = {2045-2322}, mesh = {Acetates ; *Biofilms ; Biomass ; Electrodes ; *Extracellular Polymeric Substance Matrix ; }, abstract = {Activity distribution limitation in electroactive biofilm remains an unclear phenomenon. Some observations using confocal microscopy have shown notable difference between activity close to the anode and activity at the liquid interface. A numerical model is developed in this work to describe biofilm growth and local biomass segregation in electroactive biofilm. Under our model hypothesis, metabolic activity distribution in the biofilm results from the competition between two limiting factors: acetate diffusion and electronic conduction in the biofilm. Influence of inactive biomass fraction (i.e. non-growing biomass fraction) properties (such as conductivity and density) is simulated to show variation in local biomass distribution. Introducing a dependence of effective diffusion to local density leads to a drastic biomass fraction segregation. Increasing density of inactive fraction reduces significantly acetate diffusion in biofilm, enhances biomass activity on the outer layer (liquid/biofilm interface) and maintains inner core largely inactive. High inactive fraction conductivity enhances biomass activity in the outer layer and enhances current production. Hence, investment in extracellular polymer substance (EPS), anchoring redox components, is benefit for biofilm electroactivity. However, under our model hypothesis it means that conductivity should be two order lower than biofilm conductivity reported in order to observe inner core active biomass segregation.}, } @article {pmid35390615, year = {2022}, author = {Luo, X and Yang, Y and Xie, S and Wang, W and Li, N and Wen, C and Zhu, S and Chen, L}, title = {Drying and rewetting induce changes in biofilm characteristics and the subsequent release of metal ions.}, journal = {Journal of hazardous materials}, volume = {433}, number = {}, pages = {128832}, doi = {10.1016/j.jhazmat.2022.128832}, pmid = {35390615}, issn = {1873-3336}, mesh = {Bacteria/genetics ; Biofilms ; *Cadmium ; Desiccation ; Ions ; *Metals, Heavy ; }, abstract = {Drying and rewetting can markedly influence the microbial structure and function of river biofilm communities and potentially result in the release of metal ions from biofilms containing metals. However, little information is available on the response of metal-enriched biofilms to drying and rewetting over time. In this study, natural biofilms were allowed to develop in four rotating annular bioreactors for 2-11 weeks, followed by drying for 5 days and rewetting for another 5 days. Subsequently, we assessed Zn, Cd, and As desorption from the biofilms and other related parameters (microbial community structure, biofilm morphology, enzyme activity, and surface components as well as characteristics). High-throughput sequencing of the 16 S rRNA gene and confocal laser scanning microscopy revealed that the biofilm architecture and bacterial communities were distinct in different growth phases and under drying and rewetting conditions (permutational multivariate analysis of variance; p = 0.001). Proteobacteria was the dominant bacterial phylum, accounting for 69.7-90.1% of the total content. Kinetic experiments revealed that the drying and rewetting process increased metal desorption from the biofilm matrix. The desorption of heavy metals was affected by the age of the biofilm, with the maximum amount of metal ions released from 2-week-old biofilms (one-way ANOVA, Zn: p < 0.001; Cd: p = 0.008; As: p < 0.001). The modifications in biofilm properties and decreased diversity of the bacterial community (paired t-test, p < 0.05) after drying and rewetting decreased the number of specific binding sites for metal ions. In addition, negatively charged arsenate and other anions in the liquid phase could compete with As ions for adsorption sites to promote the release of As(V) and/or reductive desorption of As(III). The results of this study and their interpretation are expected to help refine the behaviors of heavy metals in the aquatic environment.}, } @article {pmid35390370, year = {2022}, author = {Li, J and Ma, J and Liao, H and Li, X and Shen, L and Lin, H and Sun, L and Ou, R and He, D}, title = {Hot-pressed membrane assemblies enhancing the biofilm formation and nitrogen removal in a membrane-aerated biofilm reactor.}, journal = {The Science of the total environment}, volume = {833}, number = {}, pages = {155003}, doi = {10.1016/j.scitotenv.2022.155003}, pmid = {35390370}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors/microbiology ; *Denitrification ; *Nitrogen ; Oxygen ; Waste Disposal, Fluid/methods ; Wastewater/chemistry ; }, abstract = {Membrane-aerated biofilm reactor (MABR) is gaining popularity in wastewater treatment as a result of the low-energy delivery of oxygen from the carrier side and reduced sludge waste production, although its wider application suffers from the difficulty in microbial colonization on the smooth, hydrophobic membrane surface. In this study, a newly designed membrane/non-woven fabric assembly, prepared via a facile hot-pressing method, is demonstrated to be efficient in promoting the biofilm formation and nitrogen removal in MABR. The assembly achieved rough surface structure to retain biomass whilst sustained the surface hydrophobicity for a high oxygen transfer ability, which is crucial to support a resilient biofilm. Compared with the slower biomass growth and severe detachment of biofilm in the control, a thicker biofilm was quickly developed on the hot-pressed membrane assembly. High loading rates of organic matter, ammonia nitrogen and total nitrogen (TN) in the MABR using the hot-pressed membrane were 154.9 ± 5.4 g COD/(m[2]·d), 25.5 ± 0.6 g N/(m[2]·d) and 22.6 ± 0.7 g N/(m[2]·d), respectively. Particularly, the removal efficiency of TN was up to 82.8%, which was 2.5 times higher than the control. Furthermore, the biofilm grown on the hot-pressed membrane assembly organized a stable microbial community structure with a steady evolution to achieve a synergistic denitrifying function. Among the bacterial phylotypes, OLB8 might be crucial in denitrification. This study highlighted the significance of this facile membrane modification method to improve the process performance of MABR in wastewater treatment.}, } @article {pmid35390153, year = {2022}, author = {Hayer, JJ and Heinemann, C and Schulze-Dieckhoff, BG and Steinhoff-Wagner, J}, title = {A risk-oriented evaluation of biofilm and other influencing factors on biological quality of drinking water for dairy cows.}, journal = {Journal of animal science}, volume = {100}, number = {5}, pages = {}, pmid = {35390153}, issn = {1525-3163}, mesh = {Animals ; Anti-Bacterial Agents ; Bacteria ; Biofilms ; Cattle ; Dairying/methods ; *Drinking Water ; Escherichia coli ; Farms ; Female ; Lactation ; Livestock ; *Methicillin-Resistant Staphylococcus aureus ; Milk/microbiology ; }, abstract = {Despite the importance of livestock drinking water quality on animal physiology, welfare, and performance, influences such as biofilm formation on trough surfaces on microbial water quality are rarely researched. The objective of this study was to assess the microbial quality of water offered to lactating dairy cows and identify risk factors for poor water quality. We further aimed to determine the impact of biofilm formation on water quality and evaluate rapid test systems to score the hygiene status of dairy troughs on the farm. A total of 105 troughs located on 24 typical Western German dairy farms were sampled. Samples of livestock drinking water and biofilm were analyzed for aerobic total viable count (TVC), coliform count (CC), Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and other bacteria resistant to 3rd generation cephalosporins (CRB). Surface protein- and adenosine triphosphate (ATP)-rapid tests were evaluated to detect biofilm formation. The influence of 22 selected fixed and variable trough characteristics on impaired livestock drinking water quality was evaluated by calculating odds ratios. The average TVC, CC, and E. coli counts were 4.4 ± 0.06 (mean ± SD), 1.7 ± 0.1, and 0.6 ± 0.1 log10 cfu per mL, respectively. CC was detectable in 94.3% of all water samples and E. coli in 48.6%. MRSA was found in pooled livestock drinking water samples of a single farm and CRB on three farms, suggesting that troughs might function as a reservoir of antibiotic-resistant bacteria, thereby contributing to an exchange of antibiotic-resistant bacteria between animals. Risk factors for the impairment of at least one microbial quality criteria (TVC, CC, or E. coli) increased significantly (P < 0.05) when using high-volume troughs, other trough materials than stainless steel, a lower distance to the milking parlor, heavy visible soiling, biofilm formation, and high ambient and high water temperatures. CC (r = 0.46; P < 0.001) and E. coli (r = 0.31; P < 0.01) of water samples correlated with their equivalent in biofilm and with the results of rapid tests on trough surfaces (0.31 > r > 0.19; P < 0.05). Addressing the identified risk factors could be an approach to ensure sufficient biological quality of livestock drinking water.}, } @article {pmid35387914, year = {2022}, author = {Kaga, H and Nakamura, A and Orita, M and Endo, K and Akamatsu, M and Sakai, K and Sakai, H}, title = {Removal of a Model Biofilm by Sophorolipid Solutions: A QCM-D Study.}, journal = {Journal of oleo science}, volume = {71}, number = {5}, pages = {663-670}, doi = {10.5650/jos.ess21360}, pmid = {35387914}, issn = {1347-3352}, mesh = {Biofilms ; Oleic Acids ; *Quartz Crystal Microbalance Techniques ; Viscosity ; *beta-Glucans ; }, abstract = {Biofilms are communities of microorganisms that have been widely studied because they can cause hospital-acquired infections and skin disorders. Polysaccharides secreted by microorganisms are constituents of biofilms, contributing to their adhesion and mechanical stability. Sophorolipids are biosurfactants with the ability to disrupt and remove biofilms. Biosurfactants have been targeted as potential substitutes for classical petrochemical-based surfactants in cosmetics. In this study, we fabricate a β-glucan film as a model biofilm, and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements are used to assess the biofilm removal. The viscoelasticity of the β-glucan films is monitored while sophorolipid solutions are introduced into the system, and we found that the film removal performance increases with the sophorolipid concentration. In addition, Δf (change in frequency)-ΔD (change in energy dissipation) plot analyses reveal that two processes are involved in the removal mechanism. The first process involves the adsorption of water (hydration) on the β-glucan film. The second process involves the removal of the β-glucan film from the sensor surface. Furthermore, it is suggested that sophorolipids interfere with the hydration of the β-glucan film and suppress increases in its viscosity. This is expected to be an essential factor for the removal of the β-glucan film. Sophorolipids, therefore, show potential for use in cosmetics as an eco-friendly agent for biofilm removal.}, } @article {pmid35387171, year = {2022}, author = {Hu, J and Ding, Y and Tao, B and Yuan, Z and Yang, Y and Xu, K and Li, X and Liu, P and Cai, K}, title = {Surface modification of titanium substrate via combining photothermal therapy and quorum-sensing-inhibition strategy for improving osseointegration and treating biofilm-associated bacterial infection.}, journal = {Bioactive materials}, volume = {18}, number = {}, pages = {228-241}, pmid = {35387171}, issn = {2452-199X}, abstract = {Insufficient osseointegration and biofilm-associated bacterial infection are important challenges for clinical application of titanium (Ti)-based implants. Here, we constructed mesoporous polydopamine (MPDA) nanoparticles (NPs) loaded with luteolin (LUT, a quorum sensing inhibitor), which were further coated with the shell of calcium phosphate (CaP) to construct MPDA-LUT@CaP nanosystem. Then, MPDA-LUT@CaP NPs were immobilized on the surface of Ti implants. Under acidic environment of bacterial biofilm-infection, the CaP shell of MPDA-LUT@CaP NPs was rapidly degraded and released LUT, Ca[2+] and PO4 [3-] from the surface of Ti implant. LUT could effectively inhibit and disperse biofilm. Furthermore, under near-infrared irradiation (NIR), the thermotherapy induced by the photothermal conversion effect of MPDA destroyed the integrity of the bacterial membrane, and synergistically led to protein leakage and a decrease in ATP levels. Combined with photothermal therapy (PTT) and quorum-sensing-inhibition strategy, the surface-functionalized Ti substrate had an antibacterial rate of over 95.59% against Staphylococcus aureus and the elimination rate of the formed biofilm was as high as 90.3%, so as to achieve low temperature and efficient treatment of bacterial biofilm infection. More importantly, the modified Ti implant accelerated the growth of cell and the healing process of bone tissue due to the released Ca[2+] and PO4 [3-]. In summary, this work combined PTT with quorum-sensing-inhibition strategy provides a new idea for surface functionalization of implant for achieving effective antibacterial and osseointegration capabilities.}, } @article {pmid35386819, year = {2022}, author = {Yang, G and Wang, DY and Liu, Y and Huang, F and Tian, S and Ren, Y and Liu, J and An, Y and van der Mei, HC and Busscher, HJ and Shi, L}, title = {In-biofilm generation of nitric oxide using a magnetically-targetable cascade-reaction container for eradication of infectious biofilms.}, journal = {Bioactive materials}, volume = {14}, number = {}, pages = {321-334}, pmid = {35386819}, issn = {2452-199X}, abstract = {Cascade-reaction chemistry can generate reactive-oxygen-species that can be used for the eradication of infectious biofilms. However, suitable and sufficient oxygen sources are not always available near an infection site, while the reactive-oxygen-species generated are short-lived. Therefore, we developed a magnetic cascade-reaction container composed of mesoporous Fe3O4@SiO2 nanoparticles containing glucose-oxidase and l-arginine for generation of reactive-oxygen-species. Glucose-oxidase was conjugated with APTES facilitating coupling to Fe3O4@SiO2 nanoparticles and generation of H2O2 from glucose. l-arginine was loaded into the nanoparticles to generate NO from the H2O2 generated. Using an externally-applied magnetic field, cascade-reaction containers could be homogeneously distributed across the depth of an infectious biofilm. Cascade-reaction containers with coupled glucose-oxidase were effective in killing planktonic, Gram-positive and Gram-negative bacteria. Additional efficacy of the l-arginine based second cascade-reaction was only observed when H2O2 as well as NO were generated in-biofilm. In vivo accumulation of cascade-reaction containers inside abdominal Staphylococcus aureus biofilms upon magnetic targeting was observed real-time in living mice through an implanted, intra-vital window. Moreover, vancomycin-resistant, abdominal S. aureus biofilms could be eradicated consuming solely endogenous glucose, without any glucose addition. Herewith, a new, non-antibiotic-based infection-control strategy has been provided, constituting a welcome addendum to the shrinking clinical armamentarium to control antibiotic-resistant bacterial infections.}, } @article {pmid35384988, year = {2022}, author = {Levy, FM and Braga, AS and Pelá, VT and Lavender, S and Zhang, D and Pilch, S and Malheiros, Z and Stewart, B and Magalhães, AC and Buzalaf, MAR}, title = {Characterization of white spot lesions formed on human enamel under microcosm biofilm for different experimental periods.}, journal = {Journal of applied oral science : revista FOB}, volume = {30}, number = {}, pages = {e20210560}, pmid = {35384988}, issn = {1678-7765}, mesh = {Biofilms ; *Dental Caries ; Dental Enamel ; Humans ; Microradiography ; Saliva ; *Tooth Demineralization ; Tooth Remineralization ; }, abstract = {UNLABELLED: The initial characteristics of white spot lesion (WSLs), such as the degree of integrated mineral loss (ΔZ), depth and pattern of mineral distribution, have an impact on further demineralization and remineralization. However, these lesion parameters have not been evaluated in WSLs produced from microcosm biofilms.

OBJECTIVE: This study characterized artificial white spot lesions produced on human enamel under microcosm biofilm for different experimental periods.

METHODOLOGY: In total, 100 human enamel specimens (4x4mm) were assigned to 5 distinct groups (n=20/group) differing according to the period of biofilm formation (2, 4, 6, 8 or 10 days). Microcosm biofilm was produced on the specimens from a mixture of human and McBain saliva at the first 8h. Enamel samples were then exposed to McBain saliva containing 0.2% sucrose. WSLs formed were characterized by quantitative light-induced fluorescence (QLF) and transverse microradiography (TMR). Data were analyzed by ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p<0.05).

RESULTS: A clear time-response pattern was observed for both analyses, but TMR was able to better discriminate among the lesions. Regarding QLF analysis, median (95%CI; %) changes in fluorescence ∆Z were -7.74(-7.74:-6.45)a, -8.52(-8.75:-8.00)ab, -9.17(-10.00:-8.71)bc, -9.58(-10.53:-8.99)bc and -10.01(-11.44:-9.72)c for 2, 4, 6, 8, and 10 days, respectively. For TMR, median (95%CI; vol%.µm) ∆Z were 1410(1299-1479)a, 2420(2327-2604)ab, 2775(2573-2899)bc, 3305(3192-3406)cd and 4330(3972-4465)d, whereas mean (SD; µm) lesion depth were 53.7(12.3)a, 71.4(12.0)a, 103.8(24.8)b, 130.5(27.2)bc, 167.2(39.3)c for 2, 4, 6, 8 and 10 days, respectively.

CONCLUSION: The progression of WSLs formed on human enamel under microcosm biofilm can be characterized over 2-10 days, both by QLF and TMR analyses, although the latter provides better discrimination among the lesions.}, } @article {pmid35384183, year = {2022}, author = {Benny, AT and Rathinam, P and Dev, S and Mathew, B and Radhakrishnan, EK}, title = {Perillaldehyde mitigates virulence factors and biofilm formation of Pseudomonas aeruginosa clinical isolates, by acting on the quorum sensing mechanism in vitro.}, journal = {Journal of applied microbiology}, volume = {133}, number = {2}, pages = {385-399}, doi = {10.1111/jam.15565}, pmid = {35384183}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Flavoring Agents/metabolism ; Molecular Docking Simulation ; Monoterpenes ; *Pseudomonas aeruginosa/physiology ; *Quorum Sensing ; Virulence Factors/genetics/metabolism ; }, abstract = {AIM: The incidence of biofilm linked catheter-associated urinary tract infections is increasing worldwide and Pseudomonas aeruginosa is one of the major causes. Perillaldehyde (PLD): as a natural, widely used flavouring agent, has been reported to possess various pharmacological properties. We hypothesized that PLD can inhibit biofilm formation and virulence factor (VF) production by P. aeruginosa by hampering the quorum sensing (QS) system(s).

METHODS AND RESULTS: Minimum inhibitory concentration (MIC) of PLD was assessed for standard strain and two multi-drug resistant catheter isolates of P. aeruginosa utilizing the microdilution method. Microtiter plate assay, crystal violet staining and scanning electron microscopy were used to evaluate the biofilm inhibition property. CFU was utilized to assess the antifouling property of PLD. Detection of VFs and expression analysis of virulence determinants were applied to investigate the anti-virulence activity. Gene expression and molecular docking studies were also executed to explore the QS inhibition and binding of PLD with QS receptors. In the present study, PLD has significantly inhibited biofilm formation and antivirulence activity at sub-MIC levels (2.5 and 3.5 mM) in all the tested strains. In addition, molecular docking studies revealed a significant affinity towards QS receptors.

DISCUSSIONS: Perillaldehyde, being a non-toxic food flavouring agent, significantly inhibited biofilm formation and exhibited antifouling property. PLD exhibited significantly reduced levels of VFs (p < 0.001) and their respective genetic determinants (p < 0.001). Gene expression analysis and molecular docking studies confirmed the interactions of PLD to the QS receptors, indicating the plausible mechanism for the anti-virulence property.

This study identified the anti-virulence potential of PLD and provided mechanistic insights. PLD can be a suitable, non-toxic candidate for countering biofilms and associated pathogens, contributing to the prevention of biofilm-associated nosocomial infections.}, } @article {pmid35384170, year = {2022}, author = {Ahmed, HA and Ibrahim, EHS and Abdelhaliem, E and Elariny, EYT}, title = {Biotyping, virulotyping and biofilm formation ability of ESBL-Klebsiella pneumoniae isolates from nosocomial infections.}, journal = {Journal of applied microbiology}, volume = {132}, number = {6}, pages = {4555-4568}, doi = {10.1111/jam.15563}, pmid = {35384170}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Cross Infection/drug therapy ; Humans ; *Klebsiella Infections/drug therapy ; Klebsiella pneumoniae ; Microbial Sensitivity Tests ; beta-Lactamases/genetics ; }, abstract = {The aim of this study was to investigate the frequency, molecular characterization, virulence genes, resistance genes and antimicrobial profile of nosocomial extended spectrum beta lactamase producing Klebsiella species. A total of 22 (12.2%) K. pneumoniae strains were isolated from 180 clinical samples collected from hospitalized patients in Egypt. K. pneumoniae biotypes were B1 (72.8%), B3 (13.6%) and B4 (13.6%). The isolates were classified for the capsular serotypes, 86.4% (20/22) were of K1 serotype, while only two isolates (13.64%) were of K2 serotype. Hypermucoviscous K. pneumoniae isolates accounted for 68.2%. Biofilm formation ability of K. pneumoniae was determined by microtitre plate method. The majority of the isolates (40.9%) were moderate biofilm producers, while 27.3% were strong biofilm producers. All K. pneumoniae strains were positive for fimH and traT genes, while magA was identified in only 63.6% of the isolates. The antibiotic susceptibility profile of the isolates (n = 22) was determined by the disc diffusion technique using 23 different antibiotics. Streptomycin and imipenem are the most effective antibiotics against 22 tested K. pneumoniae isolates with sensitivity rates of 63.64% and 54.54% respectively. All tested K. pneumoniae isolates showed high resistance to amoxicillin∕clavulanate (100%), cefuroxime (100%) and ceftazidime (95.45%). Extended spectrum beta lactamases (ESBL) production and the presence of ESBL-related genes were tested in the isolates. All the isolates tested positive for blaVIM, NDM1 and blaTEM, while only 81.8 %tested positive for the blaSHV gene. Increasing antimicrobial resistance in K. pneumoniae causing nosocomial infections limits the use of antimicrobial agents for treatment. Furthermore, the spread of biofilm, multiple drug resistant and ESBL-producing K. pneumoniae isolates is a public threat for hospitalized patients.}, } @article {pmid35383959, year = {2022}, author = {Saavedra, FM and Pelepenko, LE and Boyle, WS and Zhang, A and Staley, C and Herzberg, MC and Marciano, MA and Lima, BP}, title = {In vitro physicochemical characterization of five root canal sealers and their influence on an ex vivo oral multi-species biofilm community.}, journal = {International endodontic journal}, volume = {55}, number = {7}, pages = {772-783}, pmid = {35383959}, issn = {1365-2591}, support = {R90 DE023058/DE/NIDCR NIH HHS/United States ; K08 DE027705/DE/NIDCR NIH HHS/United States ; K08DE027705/DE/NIDCR NIH HHS/United States ; R01DE025618/DE/NIDCR NIH HHS/United States ; R90DE023058/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; Calcium Compounds/chemistry ; *Dental Plaque ; Dental Pulp Cavity ; Epoxy Resins/chemistry ; Humans ; Materials Testing ; RNA, Ribosomal, 16S ; *Root Canal Filling Materials/chemistry/pharmacology ; Silicates/chemistry ; }, abstract = {AIM: To evaluate the physicochemical properties of five root canal sealers and assess their effect on an ex vivo dental plaque-derived polymicrobial community.

METHODOLOGY: Dental plaque-derived microbial communities were exposed to the sealers (AH Plus [AHP], GuttaFlow Bioseal [GFB], Endoseal MTA [ESM], Bio-C sealer [BCS] and BioRoot RCS [BRR]) for 3, 6 and 18 h. The sealers' effect on the biofilm biomass and metabolic activity was quantified using crystal violet (CV) staining and MTT assay, respectively. Biofilm community composition and morphology were assessed by denaturing gradient gel electrophoresis (DGGE), 16S rRNA sequencing and scanning electron microscopy. The ISO6876:2012 specifications were followed to determine the setting time, radiopacity, flowability and solubility. Obturated acrylic teeth were used to assess the sealers' effect on pH. Surface chemical characterization was performed using SEM with coupled energy-dispersive spectroscopy. Data normality was assessed using the Shapiro-Wilk test. One-way anova and Tukey's tests were used to analyze data from setting time, radiopacity, flowability and solubility. Two-way anova and Dunnett's tests were used for the data analysis from CV, MTT and pH. 16S rRNA sequencing data were analyzed for alpha (Shannon index and Chao analysis) and beta diversity (Bray-Curtis dissimilarities). Differences in community composition were evaluated by analysis of similarity (p < .05).

RESULTS: The sealers significantly influenced microbial community composition and morphology. All sealers complied with ISO6876:2012 requirements for setting time, radiopacity and flowability. Although only AHP effectively reduced the biofilm biomass, all sealers, except BRR, reduced biofilm metabolic activity.

CONCLUSION: Despite adequate physical properties, none of the sealers tested prevented biofilm growth. Significant changes in community composition were observed. If observed in vivo, these changes could affect intracanal microbial survival, pathogenicity and treatment outcomes.}, } @article {pmid35381282, year = {2022}, author = {Wang, B and Wei, PW and Yao, Y and Song, CR and Wang, X and Yang, YX and Long, YH and Yang, SW and Hu, Y and Gai, ZC and Wu, JW and Liu, HM}, title = {Functional and expression characteristics identification of Phormicins, novel AMPs from Musca domestica with anti-MRSA biofilm activity, in response to different stimuli.}, journal = {International journal of biological macromolecules}, volume = {209}, number = {Pt A}, pages = {299-314}, doi = {10.1016/j.ijbiomac.2022.03.204}, pmid = {35381282}, issn = {1879-0003}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Antimicrobial Peptides ; Biofilms ; *Houseflies/genetics ; Microbial Sensitivity Tests ; }, abstract = {Antibiotic-resistant bacteria (including MRSA) in the clinic pose a growing threat to public health, and antimicrobial peptides (AMPs) have great potential as efficient treatment alternatives. Houseflies have evolved over long periods in complex, dirty environments, developing a special immune system to overcome challenges in harmful environments. AMPs are key innate immune molecules. Herein, two differentially expressed AMPs, Phormicins A and B, were identified by screening transcriptomic changes in response to microbial stimulation. Structural mimic assays indicated that these AMPs exhibited functional divergence due to their C-terminal features. Expression analysis showed that they had different expression patterns. Phormicin B had higher constitutive expression than Phormicin A. However, Phormicin B was sharply downregulated, whereas Phormicin A was highly upregulated, after microbial stimulation. The MIC, MBC and time-growth curves showed the antibacterial spectrum of these peptides. Crystal violet staining and SEM showed that Phormicin D inhibited MRSA biofilm formation. TEM suggested that Phormicin D disrupted the MRSA cell membrane. Furthermore, Phormicin D inhibited biofilm formation by downregulating the expression of biofilm-related genes, including altE and embp. Therefore, housefly Phormicins were functionally characterized as having differential expression patterns and antibacterial & antibiofilm activities. This study provides a new potential peptide for clinical MRSA therapy.}, } @article {pmid35381253, year = {2022}, author = {Liu, M and Meng, P and Chen, G and Guan, Y and Liu, G}, title = {Correlation of structural extracellular polymeric substances in the mesh biofilms with solids retention time and biofilm hydraulic resistance in dynamic membrane bioreactors.}, journal = {The Science of the total environment}, volume = {832}, number = {}, pages = {155000}, doi = {10.1016/j.scitotenv.2022.155000}, pmid = {35381253}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; *Extracellular Polymeric Substance Matrix ; *Membranes, Artificial ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Dynamic membrane bioreactor (DMBR), which mainly relied on the in-situ formed biofilms on support materials with large aperture (e.g., nylon mesh) to separate fine particles in wastewater, has attracted a lot of attentions due to low cost. The filtration performance of DMBR is mainly determined by the structure and hydraulic resistance of biofilms formed on the mesh. Therefore, understanding the correlation of operation conditions with mesh biofilm compositions and permeability are critically important for optimizing DMBR operation. In present study, how structural extracellular polymeric substances, including alginate-like extracellular polysaccharide (ALE) and amyloid-like protein (AP), in mesh biofilms correlate to solids retention time (SRT) and biofilm structures was explored in DMBRs. At 5d-SRT, compact and gel-like mesh biofilms were formed with a high specific filtration resistance (SFR) of 459 × 10[9] m/g, while at 40d-SRT porous mesh biofilms were developed with a low SFR of 24 × 10[9] m/g. Consequently, the 5d-SRT MBR experienced more rapid rise in transmembrane pressure. Further studies found that the 5d-SRT mesh biofilms had a higher AP content, which was positively correlated to biofilm hydraulic resistance. On the contrary, the 40d-SRT mesh biofilms contained a higher content of ALE, suggesting that ALE was negatively correlated to biofilm hydraulic resistance. Therefore, AP instead of ALE likely played a more important role in the formation of compact and gel-like mesh biofilms.}, } @article {pmid35380298, year = {2022}, author = {Henagamage, AP and Peries, CM and Seneviratne, G}, title = {Fungal-bacterial biofilm mediated heavy metal rhizo-remediation.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {5}, pages = {85}, pmid = {35380298}, issn = {1573-0972}, mesh = {Bacteria ; Biodegradation, Environmental ; Biofilms ; Fungi ; *Metals, Heavy/toxicity ; Soil ; *Soil Pollutants/analysis ; }, abstract = {Heavy metal pollution due to excessive use of chemical fertilizers (CF) causes major damage to the environment. Microbial biofilms, closely associated with the rhizosphere can remediate heavy metal-contaminated soil by reducing plant toxicity. Thus, this study was undertaken to examine the remedial effects of microbial biofilms against contaminated heavy metals. Fungi and bacteria isolated from soil were screened for their tolerance against Cd[2+], Pb[2+], and Zn[2+]. Three bacterial and two fungal isolates were selected upon the tolerance index (TI) percentage. Fungal-bacterial biofilms (FBBs) were developed with the most tolerant isolates and were further screened for their bioremediation capabilities against heavy metals. The best biofilm was evaluated for its rhizoremediation capability with different CF combinations using a pot experiment conducted under greenhouse conditions with potatoes. Significantly (P < 0.05), the highest metal removal percentage was observed in Trichoderma harzianum and Bacillus subtilis biofilm under in situ conditions. When compared to the 100% recommended CF, the biofilm with 50% of the recommended CF (50CB) significantly (P < 0.05) reduced soil available Pb[2+] by 77%, Cd[2+] by 78% and Zn[2+] by 62%. In comparison to initial soil, it was 73%, 76%, and 57% lower of Pb[2+], Cd[2+], and Zn[2+], respectively. In addition, 50CB treatment significantly (P < 0.05) reduced the metal penetration into the tuber tissues in comparison with 100 C. Thus, the function of the developed FBB with T. harzianum-B. subtilis can be used as a potential solution to remediate soil polluted with Pb[2+] Cd[2+] and Zn[2+] metal contaminants.}, } @article {pmid35379908, year = {2022}, author = {Haque, MM and Biswas, MS and Mosharaf, MK and Haque, MA and Islam, MS and Nahar, K and Islam, MM and Shozib, HB and Islam, MM and Ferdous-E-Elahi, }, title = {Halotolerant biofilm-producing rhizobacteria mitigate seawater-induced salt stress and promote growth of tomato.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {5599}, pmid = {35379908}, issn = {2045-2322}, mesh = {*Alphaproteobacteria ; Biofilms ; *Solanum lycopersicum/microbiology ; Salt Stress ; Seawater ; }, abstract = {Biofilm-producing rhizobacteria (BPR) enhance productivity and mitigate abiotic stresses in plants. This study showed that 21 out of 65 halotolerant rhizobacteria could build biofilms. The components of the biofilm matrices i.e., extracellular polymeric substances (EPS) are proteins, curli, nanocelloluse, nucleic acids, lipids, and peptidoglycans. Various functional groups including carbonyl, carboxyl, amino, hydroxyl, and phosphate were identified. Positions of these groups were shifted by application of 5% NaCl, suggesting Na[+] biosorption. By sequencing, Glutamicibacter arilaitensis (ESK1, ESM4 and ESM7), G. nicotianae (ESK19, ESM8 and ESM16), Enterobacter ludwigii (ESK15, ESK17, ESM2 and ESM17), E. cloacae (ESM5 and ESM12), Exiguobacterium acetylicum (ESM24 and ESM25), Staphylococcus saprophyticus ESK6, Leclercia adecarboxylata ESK12, Pseudomonas poae ESK16, Bacillus subtilis ESM14, and P. putida ESM17 were identified. These rhizobacteria exhibited numerous plant growth-promoting (PGP) activities including producing IAA, ACC deaminase, and siderophores, and solubilizing phosphate. Under non-stress, bacterized plants increased biomass accumulation (8-23.2% roots and 23-49.4% shoots), while under seawater-induced salt stress only ESK12, ESM4, ESM12, and ESM14 enhanced biomass production (5.8-52.9% roots and 8.8-33.4% shoots). Bacterized plants induced antioxidant defense system (19.5-142% catalase and 12.3-24.2% DPPH radical scavenging activity), retained a greater relative water content (17-124%), showed lesser membrane injuries (19.9-26.5%), and a reduced Na[+] (6-24% in roots) and increased K[+]/Na[+] ratio (78.8 and 103% in roots by ESK12 and ESM24, respectively) than the non-bacterized plants in saline conditions. Thus, native halotolerant BPR can be utilized as ameliorators of salt stress.}, } @article {pmid35379855, year = {2022}, author = {Karched, M and Bhardwaj, RG and Qudeimat, M and Al-Khabbaz, A and Ellepola, A}, title = {Proteomic analysis of the periodontal pathogen Prevotella intermedia secretomes in biofilm and planktonic lifestyles.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {5636}, pmid = {35379855}, issn = {2045-2322}, mesh = {Biofilms ; *Plankton/genetics ; Prevotella intermedia ; *Proteomics ; Secretome ; }, abstract = {Prevotella intermedia is an important species associated with periodontitis. Despite the remarkable clinical significance, little is known about the molecular basis for its virulence. The aim of this study was to characterize the secretome of P. intermedia in biofilm and planktonic life mode. The biofilm secretome showed 109 proteins while the planktonic secretome showed 136 proteins. The biofilm and the planktonic secretomes contained 17 and 33 signal-peptide bearing proteins, 13 and 18 lipoproteins, respectively. Superoxide reductase, sensor histidine kinase, C40 family peptidase, elongation factor Tu, threonine synthase etc. were unique to biofilm. Of the ~ 30 proteins with predicted virulence potential from biofilm and planktonic secretomes, only 6 were common between the two groups, implying large differences between biofilm and planktonic modes of P. intermedia. From Gene Ontology biofilm secretome displayed a markedly higher percent proteins compared to planktonic secretome in terms of cellular amino acid metabolic process, nitrogen compound metabolic process etc. Inflammatory cytokine profile analysis revealed that only the biofilm secretome, not the planktonic one, induced important cytokines such as MIP-1α/MIP-1β, IL-1β, and IL-8. In conclusion, the revealed differences in the protein profiles of P. intermedia biofilm and planktonic secretomes may trigger further questions about molecular mechanisms how this species exerts its virulence potential in the oral cavity.}, } @article {pmid35379438, year = {2022}, author = {McCaughey, CS and Trebino, MA and Yildiz, FH and Sanchez, LM}, title = {Utilizing imaging mass spectrometry to analyze microbial biofilm chemical responses to exogenous compounds.}, journal = {Methods in enzymology}, volume = {665}, number = {}, pages = {281-304}, pmid = {35379438}, issn = {1557-7988}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R01 CA240423/CA/NCI NIH HHS/United States ; R01 GM125943/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods ; }, abstract = {Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) is an appealing label-free method for imaging biological samples which focuses on the spatial distribution of chemical signals. This approach has been used to study the chemical ecology of microbes and can be applied to study the chemical responses of microbes to treatment with exogenous compounds. Specific conjugated cholic acids such as taurocholic acid (TCA), have been shown to inhibit biofilm formation in the enteric pathogen Vibrio cholerae and MALDI-IMS can be used to directly observe the chemical responses of V. cholerae biofilm colonies to treatment with TCA. A major challenge of MALDI-IMS is optimizing the sample preparation and drying for a particular growth condition and microbial strain. Here we demonstrate how V. cholerae is cultured and prepared for MALDI-IMS analysis and highlight critical steps to ensure proper sample adherence to a MALDI target plate and maintain spatial distributions when applying this technique to any microbial strain. We additionally show how to use both manual interrogation and statistical analyses of MALDI-IMS data to establish the adequacy of the sample preparation protocol. This protocol can serve as a guideline for the development of sample preparation techniques and the acquisition of high quality MALDI-IMS data.}, } @article {pmid35379435, year = {2022}, author = {Eddenden, A and Nitz, M}, title = {Applications of an inactive Dispersin B probe to monitor biofilm polysaccharide production.}, journal = {Methods in enzymology}, volume = {665}, number = {}, pages = {209-231}, doi = {10.1016/bs.mie.2021.11.006}, pmid = {35379435}, issn = {1557-7988}, mesh = {Acetylglucosamine ; *Bacterial Proteins/genetics/metabolism ; *Biofilms ; Catalytic Domain ; Polysaccharides ; }, abstract = {Bacterial biofilms consist of surface-attached communities that secrete polymeric substances to form a biofilm matrix, generating a local microenvironment which helps protect from external factors. One such matrix component produced by a diverse list of microorganisms is the polysaccharide poly-β-1,6-N-acetylglucosamine (PNAG). Dispersin B is a PNAG-specific glycosyl hydrolase, which by leveraging its unique specificity, can be used to design a macromolecular fluorescent PNAG binding probe. An active site mutant of Dispersin B was fused to a fluorescent protein, to generate a probe that bound PNAG but did not hydrolyze its polysaccharide target. The ease and versatility of this strategy has made it possible to study PNAG in the context of maturing biofilms, as the probe tends to sequester in regions of high PNAG density. In this chapter, typical workflows from probe construction to cell-binding and imaging experiments are described.}, } @article {pmid35378281, year = {2022}, author = {Maurya, A and Kumar, R and Yadav, P and Singh, A and Yadav, A and Chowdhary, P and Raj, A}, title = {Biofilm formation and extracellular polymeric substance (EPS) production by Bacillus haynesii and influence of hexavalent chromium.}, journal = {Bioresource technology}, volume = {352}, number = {}, pages = {127109}, doi = {10.1016/j.biortech.2022.127109}, pmid = {35378281}, issn = {1873-2976}, mesh = {Bacillus ; Biofilms ; *Chromium ; *Extracellular Polymeric Substance Matrix ; }, abstract = {Biofilm-forming bacteria play a key role in the removal of heavy metals including hexavalent chromium [Cr(VI)] from contaminated sites. In this study, biofilm-forming B. haynesii was examined for extracellular polymeric substances (EPS) production and hexavalent chromium [Cr(VI)] reduction potential. Exposure of B. haynesii with Cr(VI) (12.5-100 mg L[-1]) for 48 h enhanced pellicle dry weight (20-24%), cell-size (5.1-23.2%) and cell granularity (8.5-19.2%). Also, EPS production was increased by 10-35% by promoting the synthesis of protein (94-119%) and polysaccharide (2-33%) components in EPS. Further, the reduction (27.7 %) and distribution (15.87%) of Cr(VI) were mainly mediated by EPS than the other cellular fractions. Findings of the study suggest that the EPS from B. haynesii was efficiently reduced to Cr(VI) present in aqueous medium and the potential of the organism can be further explored for the mitigation of Cr(VI) contamination.}, } @article {pmid35378158, year = {2022}, author = {Xu, D and Xiao, J and Jiang, D and Liu, Y and Gou, Z and Li, J and Shi, M and Wang, X and Guo, Y and Ma, L and Yin, H and Guo, L and Zhu, C and Zhang, Y and Guo, H}, title = {Inhibitory effects of a water-soluble jujube polysaccharide against biofilm-forming oral pathogenic bacteria.}, journal = {International journal of biological macromolecules}, volume = {208}, number = {}, pages = {1046-1062}, doi = {10.1016/j.ijbiomac.2022.03.196}, pmid = {35378158}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Dental Caries ; *Microbiota ; Polysaccharides/chemistry/pharmacology ; Spectroscopy, Fourier Transform Infrared ; Streptococcus mutans ; Water/pharmacology ; *Ziziphus/chemistry ; }, abstract = {Oral diseases caused by infectious pathogens raises significant concerns in public health. In the light of side effects of current antibiotics therapy and growing drug resistance of pathogenic bacteria, natural products have become attractive alternatives for antibiotics agents in dental practice. This current study investigated the effects of polysaccharides extracted from Zizyphus jujuba Mill. on three major oral biofilm-forming pathogenic bacteria including caries-inducing Streptococcus mutans, lesions-causing MRSA, and periodontitis-related Porphyromonas gingivalis, as well as general oral microbiota. Our results demonstrated that jujube polysaccharide prepared in this study was mainly composed by galacturonic acid with an average molecular weight 242 kDa, which were further characterized for structural features by FT-IR spectra and NMR spectroscopy analysis. This jujube polysaccharide was shown to exhibit remarkable inhibitory effects against all the tested oral bacterial pathogens through various mechanisms including growth inhibition, biofilm prevention and disruption, intervention of bacterial infection (adhesion and invasion), attenuation of cytotoxicity, modulation of excessive inflammatory response of LPS-stimulated and MRSA-infected macrophages as well as positive regulation of oral microbiota. The present study paves the way to explore jujube polysaccharides for the prevention and treatment of oral infectious diseases. Graphic Abstract.}, } @article {pmid35377868, year = {2022}, author = {Polizzi, B and Fanesi, A and Lopes, F and Ribot, M and Bernard, O}, title = {Understanding photosynthetic biofilm productivity and structure through 2D simulation.}, journal = {PLoS computational biology}, volume = {18}, number = {4}, pages = {e1009904}, pmid = {35377868}, issn = {1553-7358}, mesh = {Biofilms ; Carbon ; Computer Simulation ; *Microalgae ; *Photosynthesis ; }, abstract = {We present a spatial model describing the growth of a photosynthetic microalgae biofilm. In this 2D-model we consider photosynthesis, cell carbon accumulation, extracellular matrix excretion, and mortality. The rate of each of these mechanisms is given by kinetic laws regulated by light, nitrate, oxygen and inorganic carbon. The model is based on mixture theory and the behaviour of each component is defined on one hand by mass conservation, which takes into account biological features of the system, and on the other hand by conservation of momentum, which expresses the physical properties of the components. The model simulates the biofilm structural dynamics following an initial colonization phase. It shows that a 75 μm thick active region drives the biofilm development. We then determine the optimal harvesting period and biofilm height which maximize productivity. Finally, different harvesting patterns are tested and their effect on biofilm structure are discussed. The optimal strategy differs whether the objective is to recover the total biofilm or just the algal biomass.}, } @article {pmid35373364, year = {2022}, author = {Ghosh, S and Nag, M and Lahiri, D and Sarkar, T and Pati, S and Joshi, S and Ray, RR}, title = {New holistic approach for the management of biofilm-associated infections by myco-metabolites.}, journal = {Journal of basic microbiology}, volume = {62}, number = {11}, pages = {1291-1306}, doi = {10.1002/jobm.202200047}, pmid = {35373364}, issn = {1521-4028}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Biofilm-associated infections have increased excessively over the recent years due to the increased population having impaired immune systems or as a result of certain medical conditions like transplantation, cancer, and any other chronic ailments. The abrupt enhancement of antibiotic resistance and enhanced utilization of biomedical devices offer new opportunities for microbial colonization leading to the development of microbial biofilms. Total eradication of recalcitrant microbial biofilms demands the adoption of a holistic approach and since the fungal metabolites enriched with bioactive compounds show efficacy in inhibiting the multiple factors behind biofilm formation, the anti-biofilm activities of fungal metabolites need to be appraised. Being effective in preventing various steps of biofilm formation, including inhibition of surface adhesion and cell-to-cell communication through quorum quenching, blocking of quorum sensing receptors, and enzymes involved in microbial cell wall biosynthesis, targeting the virulence factors and finally killing of biofilm bound individual cells; myco-metabolites are found effective as a potent holistic anti-biofilm agent. The wide spectrum of bioactive substances of fungi and their anti-biofilm activities against different pathogens and their multitarget characteristics are very promising in the field of treating biofilm infections.}, } @article {pmid35371582, year = {2022}, author = {Sagar, PK and Sharma, P and Singh, R}, title = {Inhibition of Quorum Sensing Regulated Virulence Factors and Biofilm Formation by Eucalyptus globulus against Multidrug-Resistant Pseudomonas aeruginosa.}, journal = {Journal of pharmacopuncture}, volume = {25}, number = {1}, pages = {37-45}, pmid = {35371582}, issn = {2093-6966}, abstract = {OBJECTIVES: The quorum-sensing-inhibitory and anti-biofilm activities of the methanol extract of E. globulus leaves were determined against clinically isolated multidrug-resistant Pseudomonas aeruginosa.

METHODS: The preliminary anti-quorum-sensing (AQS) activity of eucalyptus was investigated against a biosensor strain Chromobacterium violaceum ATCC 12472 (CV12472) by using the agar well diffusion method. The effect of sub-minimum inhibitory concentrations (sub-MICs) of the methanol extract of eucalyptus on different quorum-sensing-regulated virulence factors, such as swarming motility, pyocyanin pigment, exopolysaccharide (EPS), and biofilm formation, against clinical isolates (CIs 2, 3, and 4) and reference PA01 of Pseudomonas aeruginosa were determined using the swarm diameter (mm)-measurement method, chloroform extraction method, phenol (5%)-sulphuric acid (concentrated) method, and the microtiter plate assay respectively, and the inhibition (%) in formation were calculated.

RESULTS: The preliminary AQS activity (violacein pigment inhibition) of eucalyptus was confirmed against Chromobacterium violaceum ATCC 12472 (CV12472). The eucalyptus extract also showed concentration-dependent inhibition (%) of swarming motility, pyocyanin pigment, EPS, and biofilm formation in different CIs and PA01 of P. aeruginosa.

CONCLUSION: Our results revealed the effectiveness of the E. globulus extract for the regulation of quorum-sensing-dependent virulence factors and biofilm formation at a reduced dose (sub-MICs) and suggest that E. globulus may be a therapeutic agent for curing and controlling bacterial infection and thereby reducing the possibility of resistance development in pathogenic strains.}, } @article {pmid35370181, year = {2022}, author = {Koike, M and Mitchell, RJ and Horie, T and Hummel, SK and Okabe, T}, title = {Biofilm accumulation on additive manufactured Ti-6Al-4V alloy surfaces.}, journal = {Journal of oral science}, volume = {64}, number = {2}, pages = {139-144}, doi = {10.2334/josnusd.21-0521}, pmid = {35370181}, issn = {1880-4926}, mesh = {*Alloys ; Biofilms ; Dental Alloys ; *Titanium ; }, abstract = {PURPOSE: This study investigated whether additive manufactured (AM) surfaces inhibit accumulation of bacterial biofilm on the surfaces of Ti-6Al-4V alloy dental implants. Bacterial biofilms are thought to cause peri-implant disease, which develops in mucosa surrounding titanium (Ti) and Ti alloy dental implants and can lead to bone loss and implant failure.

METHODS: Accumulation of a Streptococcus mutans (ATCC 25175) biofilm on Ti-6Al-4V alloy was compared in relation to fabrication method, ie, AM using electron beam melting (EBM) or laser beam melting (LBM). Conventional lost-wax casting was used as positive control, and Teflon was used as negative control. Biofilm accumulation on the alloys and negative control (each n = 10) was conducted at 37°C under anaerobic conditions. After 4 h, the number of metabolically active S. mutans bacteria adhering to the alloy was determined with a bioluminescence assay.

RESULTS: The quantitative roughness values of the specimens, before exposure to bacteria, ranked EBM > LBM > cast > Teflon.

CONCLUSION: The amount of biofilm accumulation on the investigated AM metals and cast metal controls did not significantly differ.}, } @article {pmid35369599, year = {2022}, author = {Ibrahim, ES and Arafa, AA and Dorgam, SM and Eid, RH and Atta, NS and El-Dabae, WH and Gaber Sadek, E}, title = {Molecular characterization of genes responsible for biofilm formation in Staphylococcus aureus isolated from mastitic cows.}, journal = {Veterinary world}, volume = {15}, number = {1}, pages = {205-212}, pmid = {35369599}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Mastitis is considered a significant disease of lactating animals. There are new attitudes for recognizing genes responsible for causing this disease to overcome and change the manipulation of this problem. This study aimed to isolate and identify Staphylococcus aureus strains from mastitic bovine animals and detect some specific biofilm-forming genes (icaA, icaD, and biofilm-associated protein [bap] genes clfA, fnbA, agrI, agrII, agrIII, agrIV, and cna).

MATERIALS AND METHODS: A total of 121 mastitic milk samples were analyzed using biochemical tests (catalase test, oxidative-fermentative test, and coagulase test) and Gram stain. Multiplex polymerase chain reaction was applied to characterize biofilm genes (icaA, icaD, bap, clfA, and fnbA) in addition to (agrI, agrII, agrIII, agrIV, and cna).

RESULTS: Among the 121 milk samples, 35 staphylococci isolates were derived with an incidence of 28.92% (35/121); among them, 19 are coagulase positive. Ninety percent of the isolates had ica genes (icaA and icaD) while bap gene was not recognized in any isolate. In addition, the incidence of fnbA, can, and clfA was 89.5% each. The prevalence of agr specific groups (agrI, agrII, agrIII, and agrIV) was 78.9%, 52.6%, 10.5%, and 15.8%, respectively.

CONCLUSION: This study concluded that S. aureus has variant mechanisms of pathogenicity to form biofilm devoid of carrying a specific gene.}, } @article {pmid35369527, year = {2022}, author = {Wang, B and Song, CR and Zhang, QY and Wei, PW and Wang, X and Long, YH and Yang, YX and Liao, SG and Liu, HM and Xu, GB}, title = {The Fusaric Acid Derivative qy17 Inhibits Staphylococcus haemolyticus by Disrupting Biofilm Formation and the Stress Response via Altered Gene Expression.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {822148}, pmid = {35369527}, issn = {1664-302X}, abstract = {Staphylococcus haemolyticus (S. haemolyticus) is the second most commonly isolated coagulase-negative staphylococcus (CoNS) in patients with hospital-acquired infections. It can produce phenol-soluble modulin (PSM) toxins and form biofilms. Compared with the wealth of information on Staphylococcus aureus and Staphylococcus epidermidis, very little is known about S. haemolyticus. There is an urgent need to find an effective preparation to combat the harm caused by S. haemolyticus infection. Chinese herbs have been utilized to cure inflammation and infectious diseases and have a long history of anticancer function in China. Here, we modified fusaric acid characterized from the metabolites of Gibberella intermedia, an endophyte previously isolated from Polygonum capitatum. This study shows that fusaric acid analogs (qy17 and qy20) have strong antibacterial activity against S. haemolyticus. In addition, crystal violet analyses and scanning electron microscopy observations demonstrated that qy17 inhibited biofilm formation and disrupted mature biofilms of S. haemolyticus in a dose-dependent manner. Additionally, it reduced the number of live bacteria inside the biofilm. Furthermore, the antibiofilm function of qy17 was achieved by downregulating transcription factors (sigB), transpeptidase genes (srtA), and bacterial surface proteins (ebp, fbp) and upregulating biofilm-related genes and the density-sensing system (agrB). To further elucidate the bacteriostatic mechanism, transcriptomic analysis was carried out. The following antibacterial mechanisms were uncovered: (i) the inhibition of heat shock (clpB, groES, groL, grpE, dnaK, dnaJ)-, oxidative stress (aphC)- and biotin response (bioB)-related gene expression, which resulted in S. haemolyticus being unable to compensate for various stress conditions, thereby affecting bacterial growth; and (ii) a reduction in the expression of PSM-beta (PSMβ1, PSMβ2, PSMβ3) toxin- and Clp protease (clpP, clpX)-related genes. These findings could have major implications for the treatment of diseases caused by S. haemolyticus infections. Our research reveals for the first time that fusaric acid derivatives inhibit the expression of biofilm formation-related effector and virulence genes of S. haemolyticus. These findings provide new potential drug candidates for hospital-acquired infections caused by S. haemolyticus.}, } @article {pmid35369456, year = {2022}, author = {Chen, K and Gao, Y and Li, L and Zhang, W and Li, J and Zhou, Z and He, H and Chen, Z and Liao, M and Zhang, J}, title = {Increased Drug Resistance and Biofilm Formation Ability in ST34-Type Salmonella Typhimurium Exhibiting Multicellular Behavior in China.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {876500}, pmid = {35369456}, issn = {1664-302X}, abstract = {Salmonella Typhimurium is an important food-borne pathogen. In this paper, multicellular behavior and associated characteristics of S. Typhimurium isolated from human and animal source food were studied. All the S. Typhimurium strains exhibiting multicellular behavior (100%) belonged to the ST34 type. In addition, most of the ST34-type multicellular behavior S. Typhimurium strains had a human origin (69.11%) and 98% of the ST34-type multicellular behavior strains exhibited strong biofilm formation capacity, which was much higher than that of non-multicellular behavior strains (7%, P < 0.01). Antibiotic resistance in ST34-type multicellular behavior strains was significantly higher than in strains with non-multicellular behavior for most conventional drugs (P < 0.05); notably, Polymyxin B (8%) and Imipenem (1%) resistances were also observed in the ST34-type strains. Furthermore, all the ST34-type multicellular behavior strains (100%) exhibited Multiple Drug Resistance (resistance to ≥3antibiotics), which was much higher than that of the non-multicellular behavior strains (P < 0.05). Consistent with the drug-resistant phenotype, the carrying rates of most drug-resistant genes in ST34-type multicellular behavior strains were higher than that those in non-multicellular behavior strains (P < 0.05). Therefore, this study revealed the emergence of a prevalent ST34-type multicellular behavior S. Typhimurium strains with increased biofilm formation ability and drug resistance rate, which poses a threat to public health safety, and highlights the need for comprehensive monitoring of the strains.}, } @article {pmid35369450, year = {2022}, author = {Zhao, D and Wang, H and Li, Z and Han, S and Han, C and Liu, A}, title = {LC_Glucose-Inhibited Division Protein Is Required for Motility, Biofilm Formation, and Stress Response in Lysobacter capsici X2-3.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {840792}, pmid = {35369450}, issn = {1664-302X}, abstract = {Glucose-inhibited division protein (GidA) plays a critical role in the growth, stress response, and virulence of bacteria. However, how gidA may affect plant growth-promoting bacteria (PGPB) is still not clear. Our study aimed to describe the regulatory function of the gidA gene in Lysobacter capsici, which produces a variety of lytic enzymes and novel antibiotics. Here, we generated an LC_GidA mutant, MT16, and an LC_GidA complemented strain, Com-16, by plasmid integration. The deletion of LC_GidA resulted in an attenuation of the bacterial growth rate, motility, and biofilm formation of L. capsici. Root colonization assays demonstrated that the LC_GidA mutant showed reduced colonization of wheat roots. In addition, disruption of LC_GidA showed a clear diminution of survival in the presence of high temperature, high salt, and different pH conditions. The downregulated expression of genes related to DNA replication, cell division, motility, and biofilm formation was further validated by real-time quantitative PCR (RT-qPCR). Together, understanding the regulatory function of GidA is helpful for improving the biocontrol of crop diseases and has strong potential for biological applications.}, } @article {pmid35368854, year = {2022}, author = {He, Z and Jiang, W and Jiang, Y and Dong, J and Song, Z and Xu, J and Zhou, W}, title = {Anti-biofilm activities of coumarin as quorum sensing inhibitor for Porphyromonas gingivalis.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {2055523}, pmid = {35368854}, issn = {2000-2297}, abstract = {Porphyromonas gingivalis is a keystone pathogen in periodontitis, a biofilm-mediated infection disease. This research aimed to investigate the effect of coumarin on P. gingivalis biofilm formation. We detected the antimicrobial effect on P. gingivalis planktonic growth, observed membrane structure and morphological change by TEM, and quantified membrane permeability by calcein-AM staining. The cell surface hydrophobicity, aggregation, and attachment were assessed. We also investigated different sub-MIC concentrations of coumarin on biofilm formation, and observed biofilm structureby confocal laser scanning microscopy. The biofilm-related gene expression was evaluated using real-time PCR. The results showed that coumarin inhibited P. gingivalis growth and damaged the cell morphology above 400 μM concentration. Coumarin did not affect cell surface hydrophobicity, aggregation, attachment, and the early stage of biofilm formation at sub-MIC concentrations. Still, it exhibited anti-biofilm effects for the late-stage and pre-formed biofilms dispersion. The biofilms after coumarin treatment became interspersed, and biofilm-related gene expression was downregulated. Coumarin also inhibited AI-2 activity and interacted with the HmuY protein by molecular docking analysis. Our research demonstrated that coumarin inhibited P. gingivalis biofilm formation through a quorum sensing system.}, } @article {pmid35368312, year = {2022}, author = {Muchova, M and Balacco, DL and Grant, MM and Chapple, ILC and Kuehne, SA and Hirschfeld, J}, title = {Fusobacterium nucleatum Subspecies Differ in Biofilm Forming Ability in vitro.}, journal = {Frontiers in oral health}, volume = {3}, number = {}, pages = {853618}, pmid = {35368312}, issn = {2673-4842}, abstract = {Development of dysbiosis in complex multispecies bacterial biofilms forming on teeth, known as dental plaque, is one of the factors causing periodontitis. Fusobacterium nucleatum (F. nucleatum) is recognised as a key microorganism in subgingival dental plaque, and is linked to periodontitis as well as colorectal cancer and systemic diseases. Five subspecies of F. nucleatum have been identified: animalis, fusiforme, nucleatum, polymorphum, and vincentii. Differential integration of subspecies into multispecies biofilm models has been reported, however, biofilm forming ability of individual F. nucleatum subspecies is largely unknown. The aim of this study was to determine the single-subspecies biofilm forming abilities of F. nucleatum ATCC type strains. Static single subspecies F. nucleatum biofilms were grown anaerobically for 3 days on untreated or surface-modified (sandblasting, artificial saliva, fibronectin, gelatin, or poly-L-lysine coating) plastic and glass coverslips. Biofilm mass was quantified using crystal violet (CV) staining. Biofilm architecture and thickness were analysed by scanning electron microscopy and confocal laser scanning microscopy. Bioinformatic analysis was performed to identify orthologues of known adhesion proteins in F. nucleatum subspecies. Surface type and treatment significantly influenced single-subspecies biofilm formation. Biofilm formation was overall highest on poly-L-lysine coated surfaces and sandblasted glass surfaces. Biofilm thickness and stability, as well as architecture, varied amongst the subspecies. Interestingly, F. nucleatum ssp. polymorphum did not form a detectable, continuous layer of biofilm on any of the tested substrates. Consistent with limited biofilm forming ability in vitro, F. nucleatum ssp. polymorphum showed the least conservation of the adhesion proteins CmpA and Fap2 in silico. Here, we show that biofilm formation by F. nucleatum in vitro is subspecies- and substrate-specific. Additionally, F. nucleatum ssp. polymorphum does not appear to form stable single-subspecies continuous layers of biofilm in vitro. Understanding the differences in F. nucleatum single-subspecies biofilm formation may shed light on multi-species biofilm formation mechanisms and may reveal new virulence factors as novel therapeutic targets for prevention and treatment of F. nucleatum-mediated infections and diseases.}, } @article {pmid35368183, year = {2022}, author = {Lee, JW and Lee, SS and Yang, SH and Choe, HS}, title = {Assessment of Bacterial Communities Within the Biofilm of Bladder Calculi in the Neurogenic Bladder Rat Model Following Spinal Cord Injury.}, journal = {International neurourology journal}, volume = {26}, number = {1}, pages = {26-30}, pmid = {35368183}, issn = {2093-4777}, abstract = {PURPOSE: To develop a rat model of bladder calculi in the neurogenic bladder following spinal cord injury (SCI) and assess bacterial communities within the biofilm of bladder calculi using denaturing gradient gel electrophoresis (DGGE).

METHODS: The silk tied to a small segment of the Teflon IV catheter was implanted through the urethra into the bladder of rats with SCI induced by T9 laminectomy. After 6 months, the rats were sacrificed and their bladder calculi were collected by opening the bladders through the low-midline incision. Genomic DNA was extracted from the biofilm of bladder calculi followed by DGGE to obtain bacterial DNA. The DNA sequences were compared and analyzed using BLAST (Basic Local Alignment Search Tool) to identify bacteria.

RESULTS: After placing silk nidus in the bladder for 6 months, all 6 rats developed bladder calculi. According to DGGE analysis, Pseudomonas aeruginosa was the most dominant strain, while Clostridium sp. and Lactobacillus sp. were relatively dominant strains within the biofilm of bladder calculi in the rats with SCI.

CONCLUSION: DGGE analysis showed various microorganisms in the biofilm of calculi arising from a neurogenic bladder rat model. This research design can be the basis for clinical studies and may be applied to calculi in patients with neurogenic bladder following SCI.}, } @article {pmid35368079, year = {2022}, author = {Chaiben, V and Yamada, CH and Telles, JP and de Andrade, AP and Arend, LNVS and Ribeiro, VST and Dantas, LR and Suss, PH and Tuon, FF}, title = {A carbapenem-resistant Acinetobacter baumannii outbreak associated with a polymyxin shortage during the COVID pandemic: an in vitro and biofilm analysis of synergy between meropenem, gentamicin and sulbactam.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {6}, pages = {1676-1684}, doi = {10.1093/jac/dkac102}, pmid = {35368079}, issn = {1460-2091}, mesh = {*Acinetobacter Infections/microbiology ; *Acinetobacter baumannii ; Ampicillin ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *COVID-19 ; Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Gentamicins/pharmacology ; Humans ; Meropenem/pharmacology ; Microbial Sensitivity Tests ; Pandemics ; Polymyxins ; Sulbactam/pharmacology ; }, abstract = {BACKGROUND: During the COVID-19 pandemic, the burden of nosocomial infections caused by MDR pathogens has caused a shortage of polymyxins. Thus, we evaluated the in vitro synergism and antibiofilm activity of antimicrobial combinations and propose a test kit for synergism against carbapenem-resistant Acinetobacter baumannii (CRAB).

METHODS: Fifty-six CRAB isolates were tested for synergy between meropenem, gentamicin and ampicillin/sulbactam. MICs were determined by broth microdilution. Synergism was tested using chequerboard analysis, followed by a time-kill curve. Additionally, minimum biofilm eradication concentration was determined and the antibiofilm activity of the combinations was evaluated by MTT assay and biomass reduction. A test kit was developed for routine laboratory testing to detect synergism.

RESULTS: All CRAB isolates were resistant to gentamicin and ampicillin/sulbactam. Chequerboard synergism occurred against 75% of the isolates. Meropenem + ampicillin/sulbactam was the most frequent combination with synergism (69%), followed by ampicillin/sulbactam + gentamicin (64%) and meropenem + gentamicin (51%). All combinations presented only bacteriostatic activity and no bactericidal or antibiofilm effects. The routine laboratory test showed 100% accuracy compared with other in vitro assays.

CONCLUSIONS: Our study demonstrates the potential role of antibiotic combinations against planktonic bacteria. In vitro synergism is possible and can be an alternative treatment for patients with CRAB infection during a polymyxin shortage.}, } @article {pmid35367853, year = {2022}, author = {Melian, C and Bentencourt, E and Castellano, P and Ploper, D and Vignolo, G and Mendoza, LM}, title = {Biofilm genes expression of Listeria monocytogenes exposed to Latilactobacillus curvatus bacteriocins at 10 °C.}, journal = {International journal of food microbiology}, volume = {370}, number = {}, pages = {109648}, doi = {10.1016/j.ijfoodmicro.2022.109648}, pmid = {35367853}, issn = {1879-3460}, mesh = {*Bacteriocins/metabolism ; Biofilms ; Lactobacillus/metabolism ; *Listeria monocytogenes/genetics ; }, } @article {pmid35367555, year = {2022}, author = {Lan, J and Ren, Y and Luo, H and Wang, X and Liu, G and Zhang, R}, title = {High current density with spatial distribution of Geobacter in anodic biofilm of the microbial electrolysis desalination and chemical-production cell with enlarged volumetric anode.}, journal = {The Science of the total environment}, volume = {831}, number = {}, pages = {154798}, doi = {10.1016/j.scitotenv.2022.154798}, pmid = {35367555}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources/microbiology ; Biofilms ; Electrodes ; Electrolysis ; *Geobacter ; RNA, Ribosomal, 16S ; }, abstract = {The aim of this study was to establish the relationship between spatial distribution of Geobacter and electric intensity in the microbial electrolysis desalination and chemical-production cell (MEDCC) and to investigate the effect of enlarged volumetric anode on the performance of MEDCC. The MEDCC was constructed with nine carbon brush anodes (length × diameter = 11 cm × 3 cm) as enlarged volumetric anode, and operated by feeding with 1 g/L acetate as substrate and 35 g/L NaCl as artificial seawater under the applied voltages of 1.2-4.5 V. Spatial distribution of Geobacter in the anodic biofilm was determined according to the bacterial community analysis on 27 biofilm samples from the top, middle and bottom layers of anodes (i.e., with distance of 4.5, 10, and 15.5 cm to the cathode, respectively). Results showed that the enlarged volumetric anode significantly improved the performance of MEDCC. The maximum desalination rate and current density reached 338.5 ± 21.8 mg/L∙h and 55.7 ± 3.7 A/m[2] in the MEDCC, respectively. The electric intensity values decreased with the distance from the anode to the cathode and formed an uneven distribution in the anode chamber. The samples in the top layer of anodes had the highest average 16S rRNA gene copy number of Geobacter of 1.55 × 10[7] copies/μL, which was 18 times higher than that in the bottom layer of anodes. A linear relation was established between the spatial distribution of Geobacter and electric intensity (R[2] = 0.994-0.999). The electric intensity gradient created the uneven spatial distribution of Geobacter in the biofilms of volumetric anode. Results from this study could be useful to enrich Geobacter in the anodic biofilm thus to improve the performance of MEDCC.}, } @article {pmid35367266, year = {2022}, author = {Learbuch, KLG and Smidt, H and van der Wielen, PWJJ}, title = {Water and biofilm in drinking water distribution systems in the Netherlands.}, journal = {The Science of the total environment}, volume = {831}, number = {}, pages = {154940}, doi = {10.1016/j.scitotenv.2022.154940}, pmid = {35367266}, issn = {1879-1026}, mesh = {Adenosine Triphosphate ; Bacteria ; Biofilms ; *Drinking Water ; Netherlands ; Water Microbiology ; Water Quality ; *Water Supply ; }, abstract = {To keep the high quality of drinking water in the future for non-chlorinated drinking water systems, knowledge about the variables that most strongly affect this quality is necessary in order to know where to focus on and possibly even change aspects of drinking water production and distribution. Therefore, the aim of this study was to investigate which variables (source of drinking water, growth potential and pipe material type) have the biggest influence on bacterial community composition and biomass concentration of drinking water and biofilm in distribution systems. Ten different distribution systems were sampled for water and biofilm, obtained from four different pipe materials, throughout the Netherlands. The distribution systems are supplied either with drinking water produced from groundwater or surface water, and differ in drinking water quality parameters such as the growth potential. We found a significant relationship for growth potential and ATP concentration in water, but for the ATP in the biofilm none of the parameters showed a significant effect. Furthermore, the source of the drinking water and the pipe material did not significantly affect the ATP concentration in water and biofilm. The bacterial composition of in both water and biofilm was significantly different between distribution systems delivering water with low and high growth potential and between drinking water produced from groundwater or surface water. In contrast, the different pipe materials did not significantly affect composition of biofilm-associated communities. We conclude from these results that the growth potential of the treated water best explains the variation in biomass and bacterial composition in water and biofilm of non-chlorinated drinking water distribution systems followed by the drinking water source, whereas pipe materials seem to be of lesser importance.}, } @article {pmid35366684, year = {2023}, author = {Bashir, A and Ahmad, T and Farooq, S and Lone, WI and Manzoor, MM and Nalli, Y and Sultan, P and Chaubey, A and Ali, A and Riyaz-Ul-Hassan, S}, title = {A Secondary Metabolite of Cercospora sp., Associated with Rosa damascena Mill., Inhibits Proliferation, Biofilm Production, Ergosterol Synthesis and Other Virulence Factors in Candida albicans.}, journal = {Microbial ecology}, volume = {85}, number = {4}, pages = {1276-1287}, pmid = {35366684}, issn = {1432-184X}, mesh = {*Candida albicans/metabolism ; Virulence Factors/metabolism ; *Rosa/metabolism ; Cercospora/metabolism ; Molecular Docking Simulation ; Phylogeny ; Biofilms ; Ergosterol/metabolism ; Cell Proliferation ; Antifungal Agents/pharmacology/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Here we describe the antimicrobial potential of secondary metabolites, fulvic acid (F.A.) and anhydrofulvic acid (AFA), produced by RDE147, an endophyte of Rosa damascena Mill. The endophyte was identified as Cercospora piaropi by ITS and β-tubulin-based phylogenetic analyses, while chemoprofiling of the endophyte by column chromatography and spectroscopy yielded two pure compounds, F.A. and AFA. The compounds demonstrated different antimicrobial profiles, with AFA suppressing the growth of C. albicans at 7.3 µg ml[-1] IC50. Further studies revealed that AFA strongly restricted the biofilm production and hyphae formation in C. albicans by down-regulating several biofilm and morphogenesis-related genes. The time-kill assays confirmed the fungicidal activity of AFA against C. albicans, killing 83.6% of the pathogen cells in 24 h at the MIC concentration, and the post-antibiotic effect (PAE) experiments established the suppression of C. albicans growth for extended time periods. The compound acted synergistically with amphotericin B and nystatin and reduced ergosterol biosynthesis by the pathogen, confirmed by ergosterol estimation and comparative expression profiling of selected genes and molecular docking of AFA with C. albicans squalene epoxidase. AFA also suppressed the expression of several other virulence genes of the fungal pathogen. The study determines the anti-C. albicans potential of AFA and its impact on the biology of the pathogen. It also indicates that Cercospora species may yield potential bioactive molecules, especially fulvic acid derivatives. However, it is imperative to conduct in vivo studies to explore this molecule's therapeutic potential further.}, } @article {pmid35365607, year = {2022}, author = {Krause, S and Gfrerer, S and von Kügelgen, A and Reuse, C and Dombrowski, N and Villanueva, L and Bunk, B and Spröer, C and Neu, TR and Kuhlicke, U and Schmidt-Hohagen, K and Hiller, K and Bharat, TAM and Rachel, R and Spang, A and Gescher, J}, title = {The importance of biofilm formation for cultivation of a Micrarchaeon and its interactions with its Thermoplasmatales host.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {1735}, pmid = {35365607}, issn = {2041-1723}, support = {/WT_/Wellcome Trust/United Kingdom ; 202231/Z/16/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Archaea/genetics ; Biofilms ; Genome, Archaeal ; Phylogeny ; *Thermoplasmales/genetics/metabolism ; }, abstract = {Micrarchaeota is a distinctive lineage assigned to the DPANN archaea, which includes poorly characterised microorganisms with reduced genomes that likely depend on interactions with hosts for growth and survival. Here, we report the enrichment of a stable co-culture of a member of the Micrarchaeota (Ca. Micrarchaeum harzensis) together with its Thermoplasmatales host (Ca. Scheffleriplasma hospitalis), as well as the isolation of the latter. We show that symbiont-host interactions depend on biofilm formation as evidenced by growth experiments, comparative transcriptomic analyses and electron microscopy. In addition, genomic, metabolomic, extracellular polymeric substances and lipid content analyses indicate that the Micrarchaeon symbiont relies on the acquisition of metabolites from its host. Our study of the cell biology and physiology of a Micrarchaeon and its host adds to our limited knowledge of archaeal symbioses.}, } @article {pmid35364199, year = {2022}, author = {Vinotha, V and Yazhiniprabha, M and Jeyavani, J and Vaseeharan, B}, title = {Synthesis and characterization of cry protein coated zinc oxide nanocomposites and its assessment against bacterial biofilm and mosquito vectors.}, journal = {International journal of biological macromolecules}, volume = {208}, number = {}, pages = {935-947}, doi = {10.1016/j.ijbiomac.2022.03.165}, pmid = {35364199}, issn = {1879-0003}, mesh = {Animals ; Anti-Bacterial Agents/chemistry ; Biofilms ; *Insecticides/chemistry ; *Metal Nanoparticles/chemistry ; Mosquito Vectors ; *Nanocomposites ; Plant Extracts/chemistry ; Plant Leaves/chemistry ; Pseudomonas aeruginosa ; Staphylococcus aureus ; *Zinc Oxide/chemistry/pharmacology ; }, abstract = {Mosquitoes need to be eradicated as they can spread deadly diseases. Cry toxic proteins from Bacillus and zinc oxide nanoparticles also can tremendously control pest and bacterial pathogens. With this reference, the Ac-ZnO NPs was effectively synthesized using Acorus calamus rhizomes extract where after incorporated with bacterial cry toxic protein (Btp) to produce Btp-Ac-ZnO nanocomposites. The XRD and FTIR, disclose the crystalline form with an average size of 17.47 nm and the possible biomolecules of Btp-Ac-ZnO NCs. SEM and TEM make known the well agglomerated and cone shape of Btp-Ac-ZnO NCs. The NCs show concentration-dependent antioxidant activity. Btp-Ac-ZnO NCs drastically arrest the formation of biofilm by the pathogenic bacteria such as E. faecalis, S. aureus, P. aeruginosa, and P. vulgaris at 100 μg/mL. All the above, the Btp-Ac-ZnO NCs exhibits superior larvicidal activity against three mosquito vectors namely Ae. aegypti, An. stephensi and Cx. quinquefasciatus with LC50 values of 43.76, 39.60 and 37.13 μg/mL respectively. Besides, the biological enzymes are significantly reduced in the treated larvae than that of untreated one, which indicates the effect of Btp-Ac-ZnO NCs. Since, the Btp-Ac-ZnO NCs could be utilized against the pathogenic bacteria, and its biofilm structure, and also in the vector control sectors.}, } @article {pmid35357222, year = {2022}, author = {Lacasse, M and Valentin, AS and Corvec, S and Bémer, P and Jolivet-Gougeon, A and Plouzeau, C and Tandé, D and Mereghetti, L and Bernard, L and Lartigue, MF and , }, title = {Genotypic Characterization and Biofilm Production of Group B Streptococcus Strains Isolated from Bone and Joint Infections.}, journal = {Microbiology spectrum}, volume = {10}, number = {2}, pages = {e0232921}, pmid = {35357222}, issn = {2165-0497}, mesh = {Adhesins, Bacterial/genetics ; Biofilms ; Female ; Genotype ; Humans ; Multilocus Sequence Typing ; Phylogeny ; *Streptococcal Infections ; *Streptococcus agalactiae/genetics ; }, abstract = {Bone and joint infections (BJI) represent the second cause of invasive Group B Streptococcus (GBS) infections. Biofilm formation plays a major role in BJI. This study's aim was to analyze the genetic features and biofilm production of GBS strains. In six French laboratories, 77 GBS strains isolated from BJI and 57 strains from vaginal human colonization (Hcol) were characterized and compared by Multi-Locus Sequence Typing (MLST). PCR was used to search for the adhesins (bsaB, lmb, scpB, fbsA, fbsB, hvgA, bibA, bca, srr-1, and srr-2) and Pilus Islands (PI) related genes (PI-1, PI-2a, PI-2b). Biofilm production was studied by crystal violet assay. Strains were categorized into three groups, based on Specific Biofilm Formation (SBF) values defined as: weak, moderate, or strong producers. Molecular study revealed three major clonal complexes (CC) in BJI strains: CC1 (42%), CC23 (22%) and CC10 (14%). Several associations between CC and adhesin/pili were identified: CC1 with srr2, PI-1 + 2a; CC10 with srr-1, bca, PI-1 + 2a; CC17 with fbsB, hvgA, srr-2, PI-1+PI-2b; CC19 with bibA, srr-1, PI-1 + 2a; CC23 with fbsB, bibA, srr-1, PI-2a. The biofilm production was significantly different according to CC, adhesins and pili gene detection. CC10, CC23 and strains harboring fbsB produce more biofilm than CC1, PI-1 + 2a (independently). Finally, SBF values were significantly stronger for Hcol strains rather than for BJI strains (76% versus 40%). This study revealed that Hcol strains appeared to produce stronger biofilm than BJI strains, though they belonged to similar CCs and had the same adhesin and pili content. IMPORTANCE Bone and joint infections (BJI) are pathologies that can be life-threatening and result in compromised functional prognosis for patients. Relapses are common and often related to biofilm formation. Group B streptococci (GBS) BJI increased since the last decade. However, few data are available on this subject in the literature. Our study aims to highlight genotype and biofilm production of GBS isolates from BJI. Seventy-seven GBS strains isolated from BJI and 57 from asymptomatic human vaginal colonization were characterized by multilocus sequence typing (MLST), adhesins content, nature of the pili and the ability to form biofilm. Our results revealed that vaginal human colonization strains produced stronger biofilm than BJI strains, despite belonging to the same phylogenetic lineage and having the same adhesin and pili content.}, } @article {pmid35357191, year = {2022}, author = {Borlee, GI and Mangalea, MR and Martin, KH and Plumley, BA and Golon, SJ and Borlee, BR}, title = {Disruption of c-di-GMP Signaling Networks Unlocks Cryptic Expression of Secondary Metabolites during Biofilm Growth in Burkholderia pseudomallei.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {8}, pages = {e0243121}, pmid = {35357191}, issn = {1098-5336}, mesh = {Bacillus subtilis/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Burkholderia pseudomallei/genetics ; Cyclic GMP/analogs & derivatives ; }, abstract = {The regulation and production of secondary metabolites during biofilm growth of Burkholderia spp. is not well understood. To learn more about the crucial role and regulatory control of cryptic molecules produced during biofilm growth, we disrupted c-di-GMP signaling in Burkholderia pseudomallei, a soilborne bacterial saprophyte and the etiologic agent of melioidosis. Our approach to these studies combined transcriptional profiling with genetic deletions that targeted key c-di-GMP regulatory components to characterize responses to changes in temperature. Mutational analyses and conditional expression studies of c-di-GMP genes demonstrates their contribution to phenotypes such as biofilm formation, colony morphology, motility, and expression of secondary metabolite biosynthesis when grown as a biofilm at different temperatures. RNA-seq analysis was performed at various temperatures in a ΔII2523 mutant background that is responsive to temperature alterations resulting in hypobiofilm- and hyperbiofilm-forming phenotypes. Differential regulation of genes was observed for polysaccharide biosynthesis, secretion systems, and nonribosomal peptide and polyketide synthase (NRPS/PKS) clusters in response to temperature changes. Deletion mutations of biosynthetic gene clusters (BGCs) 2, 11, 14 (syrbactin), and 15 (malleipeptin) in parental and ΔII2523 backgrounds also reveal the contribution of these BGCs to biofilm formation and colony morphology in addition to inhibition of Bacillus subtilis and Rhizoctonia solani. Our findings suggest that II2523 impacts the regulation of genes that contribute to biofilm formation and competition. Characterization of cryptic BGCs under different environmental conditions will allow for a better understanding of the role of secondary metabolites in the context of biofilm formation and microbe-microbe interactions. IMPORTANCE Burkholderia pseudomallei is a saprophytic bacterium residing in the environment that switches to a pathogenic lifestyle during infection of a wide range of hosts. The environmental cues that serve as the stimulus to trigger this change are largely unknown. However, it is well established that the cellular level of c-di-GMP, a secondary signal messenger, controls the switch from growth as planktonic cells to growth as a biofilm. Disrupting the signaling mediated by c-di-GMP allows for a better understanding of the regulation and the contribution of the surface associated and secreted molecules that contribute to the various lifestyles of this organism. The genome of B. pseudomallei also encodes cryptic biosynthetic gene clusters predicted to encode small molecules that potentially contribute to growth as a biofilm, adaptation, and interactions with other organisms. A better understanding of the regulation of these molecules is crucial to understanding how this versatile pathogen alters its lifestyle.}, } @article {pmid35353911, year = {2022}, author = {Wang, H and Zou, H and Wang, Y and Jin, J and Wang, H and Zhou, M}, title = {Inhibition effect of epigallocatechin gallate on the growth and biofilm formation of Vibrio parahaemolyticus.}, journal = {Letters in applied microbiology}, volume = {75}, number = {1}, pages = {81-88}, doi = {10.1111/lam.13712}, pmid = {35353911}, issn = {1472-765X}, support = {2017YFC1600100//National Key R&D Program of China/ ; 31471660//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Catechin/analogs & derivatives/pharmacology ; *Vibrio parahaemolyticus ; }, abstract = {Vibrio parahaemolyticus is a common marine foodborne pathogen that causes gastroenteritis. With the long-term use of antibiotics, many bacteria become resistant; therefore, developing antibiotic-free antimicrobial strategies is urgent. Epigallocatechin gallate (EGCG), a constituent of polyphenols present abundantly in tea extract, has broad-spectrum antibacterial activity and is non-toxic. Here, we take advantage of these properties of EGCG to evaluate its inhibition effect on the growth and biofilm formation of V. parahaemolyticus 17802, and explore its antibacterial mechanism. It was found that EGCG showed antibacterial activity against V. parahaemolyticus 17802, and the minimum inhibitory concentration (MIC) was estimated to be 128 μg ml[-1] . Results of crystal violet staining and confocal laser scanning microscope (CLSM) evidenced that EGCG hindered its biofilm formation. Moreover, the swimming motility and extracellular polysaccharides were also notably inhibited. The antibacterial mechanism was further confirmed by several assays, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and live/dead staining assay, together with membrane permeability assay, which all suggested that EGCG caused damage to cell membrane and made it lose integrity, eventually resulting in the death of V. parahaemolyticus 17802. The bactericidal activity of EGCG verified its potential as a promising candidate to combat foodborne pathogen.}, } @article {pmid35351893, year = {2022}, author = {Gahlot, DK and Wai, SN and Erickson, DL and Francis, MS}, title = {Cpx-signalling facilitates Hms-dependent biofilm formation by Yersinia pseudotuberculosis.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {13}, pmid = {35351893}, issn = {2055-5008}, mesh = {Animals ; Biofilms ; Caenorhabditis elegans/microbiology ; Signal Transduction ; *Yersinia pseudotuberculosis/genetics/metabolism ; }, abstract = {Bacteria often reside in sessile communities called biofilms, where they adhere to a variety of surfaces and exist as aggregates in a viscous polymeric matrix. Biofilms are resistant to antimicrobial treatments, and are a major contributor to the persistence and chronicity of many bacterial infections. Herein, we determined that the CpxA-CpxR two-component system influenced the ability of enteropathogenic Yersinia pseudotuberculosis to develop biofilms. Mutant bacteria that accumulated the active CpxR~P isoform failed to form biofilms on plastic or on the surface of the Caenorhabditis elegans nematode. A failure to form biofilms on the worm surface prompted their survival when grown on the lawns of Y. pseudotuberculosis. Exopolysaccharide production by the hms loci is the major driver of biofilms formed by Yersinia. We used a number of molecular genetic approaches to demonstrate that active CpxR~P binds directly to the promoter regulatory elements of the hms loci to activate the repressors of hms expression and to repress the activators of hms expression. Consequently, active Cpx-signalling culminated in a loss of exopolysaccharide production. Hence, the development of Y. pseudotuberculosis biofilms on multiple surfaces is controlled by the Cpx-signalling, and at least in part this occurs through repressive effects on the Hms-dependent exopolysaccharide production.}, } @article {pmid35350627, year = {2022}, author = {Billaud, M and Seneca, F and Tambutté, E and Czerucka, D}, title = {An Increase of Seawater Temperature Upregulates the Expression of Vibrio parahaemolyticus Virulence Factors Implicated in Adhesion and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {840628}, pmid = {35350627}, issn = {1664-302X}, abstract = {Climate change driven seawater temperature (SWT) increases results in greater abundance and geographical expansion of marine pathogens, among which Vibrio parahaemolyticus (Vp) causes serious economic and health issues. In addition, plastic pollution in the ocean constitutes a vector for harmful pathogens dissemination. We investigate the effect of elevated SWT on the expression of genes implicated in adhesion and biofilm formation on abiotic surfaces in the clinical Vp strain RIMD2210633, which expresses hemolysins. Among the genes studied, the multivalent adhesion molecule-7 and the GlcNAc-binding protein A were involved in the adhesion of Vp to abiotic and biotic surfaces, whereas the type IV pili, the mannose-sensitive hemagglutinin, and the chitin-regulated pilins facilitate attachment and biofilm formation. Data presented here show that at 21°C, Vp is still viable but does not either proliferate or express the virulence factors studied. Interestingly, at 27°C and as early as 1 h of incubation, all factors are transiently expressed in free-living bacteria only and even more upregulated at 31°C. These results clearly show that increased SWT has an important impact on the adhesion properties of free-living Vp to plastic support and thus emphasize the role of climate change in the spread of this pathogenic bacteria.}, } @article {pmid35350439, year = {2022}, author = {Rashid, S and Correia-Mesquita, TO and Godoy, P and Omran, RP and Whiteway, M}, title = {SAGA Complex Subunits in Candida albicans Differentially Regulate Filamentation, Invasiveness, and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {764711}, pmid = {35350439}, issn = {2235-2988}, support = {MOP42516//CIHR/Canada ; }, mesh = {Biofilms ; *Candida albicans/genetics/metabolism ; Fungal Proteins/genetics/metabolism ; Histone Acetyltransferases/genetics/metabolism ; *Transcription Factors/metabolism ; }, abstract = {SAGA (Spt-Ada-Gcn5-acetyltransferase) is a highly conserved, multiprotein co-activator complex that consists of five distinct modules. It has two enzymatic functions, a histone acetyltransferase (HAT) and a deubiquitinase (DUB) and plays a central role in processes such as transcription initiation, elongation, protein stability, and telomere maintenance. We analyzed conditional and null mutants of the SAGA complex module components in the fungal pathogen Candida albicans; Ngg1, (the HAT module); Ubp8, (the DUB module); Tra1, (the recruitment module), Spt7, (the architecture module) and Spt8, (the TBP interaction unit), and assessed their roles in a variety of cellular processes. We observed that spt7Δ/Δ and spt8Δ/Δ strains have a filamentous phenotype, and both are highly invasive in yeast growing conditions as compared to the wild type, while ngg1Δ/Δ and ubp8Δ/Δ are in yeast-locked state and non-invasive in both YPD media and filamentous induced conditions compared to wild type. RNA-sequencing-based transcriptional profiling of SAGA mutants reveals upregulation of hyphal specific genes in spt7Δ/Δ and spt8Δ/Δ strains and downregulation of ergosterol metabolism pathway. As well, spt7Δ/Δ and spt8Δ/Δ confer susceptibility to antifungal drugs, to acidic and alkaline pH, to high temperature, and to osmotic, oxidative, cell wall, and DNA damage stresses, indicating that these proteins are important for genotoxic and cellular stress responses. Despite having similar morphological phenotypes (constitutively filamentous and invasive) spt7 and spt8 mutants displayed variation in nuclear distribution where spt7Δ/Δ cells were frequently binucleate and spt8Δ/Δ cells were consistently mononucleate. We also observed that spt7Δ/Δ and spt8Δ/Δ mutants were quickly engulfed by macrophages compared to ngg1Δ/Δ and ubp8Δ/Δ strains. All these findings suggest that the SAGA complex modules can have contrasting functions where loss of Spt7 or Spt8 enhances filamentation and invasiveness while loss of Ngg1 or Ubp8 blocks these processes.}, } @article {pmid35349844, year = {2022}, author = {Sanchez-Huerta, C and Fortunato, L and Leiknes, T and Hong, PY}, title = {Influence of biofilm thickness on the removal of thirteen different organic micropollutants via a Membrane Aerated Biofilm Reactor (MABR).}, journal = {Journal of hazardous materials}, volume = {432}, number = {}, pages = {128698}, doi = {10.1016/j.jhazmat.2022.128698}, pmid = {35349844}, issn = {1873-3336}, mesh = {Bacteria ; Biofilms ; *Bioreactors/microbiology ; Humans ; Nitrification ; Waste Disposal, Fluid/methods ; *Wastewater/chemistry ; Water ; }, abstract = {The presence of organic micropollutants (OMPs) in natural water bodies has become an emerging concern due to their fast dissemination into natural water sources, high persistence, ubiquitous nature, and detrimental impact on the environment and human health. This study evaluated the Membrane Aerated Biofilm Reactor (MABR) efficiency in the removal of 13 OMPs commonly reported in water. Results demonstrated that OMPs removal is dependent on biofilm thickness and bacterial cell density, microbial community composition and physicochemical properties of OMPs. Effective removals of ammonium and organic carbon (COD, >50%), acetaminophen (70%) and triclosan (99%) were obtained even at early stages of biofilm development (thickness < 0.33 mm, 2.9 ×10[5] cell mL[-1]). An increase in biofilm thickness and cell density (1.02 mm, 2.2 ×10[6] cell mL[-1]) enhanced the system performance. MABR achieved over 90% removal of nonpolar, hydrophobic and hydrophilic OMPs and 22-69% removal of negatively charged and acidic OMPs. Relative abundances of Zoogloea, Aquabacterium, Leucobacter, Runella, and Paludilbaculum bacteria correlated with the removal of certain OMPs. In addition, MABR achieved up to 96% nitrification and 80% overall COD removal by the end of the experiment. The findings from this study demonstrated MABRs to be a feasible option to treat municipal wastewater polluted by OMPs.}, } @article {pmid35348927, year = {2022}, author = {Song, Y and Sun, Q and Luo, J and Kong, Y and Pan, B and Zhao, J and Wang, Y and Yu, C}, title = {Cationic and Anionic Antimicrobial Agents Co-Templated Mesostructured Silica Nanocomposites with a Spiky Nanotopology and Enhanced Biofilm Inhibition Performance.}, journal = {Nano-micro letters}, volume = {14}, number = {1}, pages = {83}, pmid = {35348927}, issn = {2150-5551}, abstract = {HIGHLIGHTS: A ‘dual active templating’ strategy is firstly reported, using cationic and anionic bactericidal agents as co-templates for the preparation of antibacterial silica nanocomposite with spiky nanotopography. The spiky nanocomposite exhibited enhanced antibacterial and biofilm inhibition performance, compared to pure antimicrobial cationic agent templated smooth silica nanocomposite.

ABSTRACT: Silica-based materials are usually used as delivery systems for antibacterial applications. In rare cases, bactericidal cationic surfactant templated silica composites have been reported as antimicrobial agents. However, their antibacterial efficacy is limited due to limited control in content and structure. Herein, we report a “dual active templating” strategy in the design of nanostructured silica composites with intrinsic antibacterial performance. This strategy uses cationic and anionic structural directing agents as dual templates, both with active antibacterial property. The cationic-anionic dual active templating strategy further contributes to antibacterial nanocomposites with a spiky surface. With controllable release of dual active antibacterial agents, the spiky nanocomposite displays enhanced anti-microbial and anti-biofilm properties toward Staphylococcus epidermidis. These findings pave a new avenue toward the designed synthesis of novel antibacterial nanocomposites with improved performance for diverse antibacterial applications. [Image: see text]

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40820-022-00826-4.}, } @article {pmid35348904, year = {2022}, author = {Sallami, I and Turki, Y and Werheni Ammeri, R and Khelifi, N and Hassen, A}, title = {Effects of heavy metals on growth and biofilm-producing abilities of Salmonella enterica isolated from Tunisia.}, journal = {Archives of microbiology}, volume = {204}, number = {4}, pages = {225}, pmid = {35348904}, issn = {1432-072X}, mesh = {Biofilms ; *Metals, Heavy/toxicity ; *Salmonella enterica/genetics ; Tunisia ; Zinc ; }, abstract = {This study aims to test the toxicity of some metallic elements on Salmonella enterica strains and their power to grow and to develop a biofilm to overcome this environmental stress. From 50 selected strains of Salmonella, 70% belong to the Kentucky serotypes that is the most frequent one, followed by the other serotypes such as Amsterdam 6%, anatum 4%, derby 4% Enteritidis 4%, Zanzibar 4%, typhyrimium 2%, gallinaruim 2%, inbondaka 2% and Newport 2%. All the strains have presented the invA invasion gene involved in the virulence and Salmonella infection. Genotypic BOX-PCR analysis of these strains showed 18 profiles, with a discrimination index of 0.93. The Salmonella growth has mainly revealed that the variation of the rates of different metallic elements showed a significant influence on the Salmonella growth. The qualitative, quantitative study and biofilm tubes showed that 40% of the strains have a strong capacity to form biofilm, and the wild-type phenotypes (RDAR; rigid film; Strong), This phenotype varies according to the nature and the concentration of the metal (0.1 mM-1 mM) considered. In the presence of copper, zinc, cobalt, and chromium, the Salmonella strains showed a potent capacity to form a biofilm with a slight variation in the wild-type phenotype. However, when chromium rates increased, Salmonella loses the RDAR morphotype. Addition of mercury and cadmium in the growth medium reduced the production of Salmonella biofilm by around 14 and 15%, respectively, if compared with the control free of metals.}, } @article {pmid35348424, year = {2022}, author = {Silva, BG and Perez-Calleja, P and Foresti, E and Nerenberg, R}, title = {Unique biofilm structure and mass transfer mechanisms in the foam aerated biofilm reactor (FABR).}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/09593330.2022.2058422}, pmid = {35348424}, issn = {1479-487X}, abstract = {The foam-aerated biofilm reactor (FABR) is a novel biofilm process that can simultaneously remove carbon and nitrogen from wastewater. A porous polyurethane foam sheet forms an interface between wastewater and aerated water, making it a counter-diffusional biofilm process similar to the membrane-aerated biofilm reactor (MABR). However, it is not clear how biofilm develops the foam interior, and how this impacts mass transfer and performance. This research explored biofilm development within the foam sheet and determined whether advective transport within the sheet played a significant role. Foam sheets with 2-, 4.5- and 9-mm thicknesses were explored. Oxygen, nitrate, nitrite and ammonia profiles in the sheet were measured using microsensors, and biofilm imaging studies were carried out using optical coherence tomography (OCT). On the foam's aerated side, a dense nitrifying biofilm formed. Beyond the aerobic zone, much less biomass was observed, with a high porosity foam-biofilm layer. The higher effective diffusivity within the foam for the 4- and 9-mm sheets suggested advective transport within the foam channel structures. Using an effective diffusivity factor in conventional 1-D biofilm models reproduced the measured substrate concentration profiles within the foam. Four different practical conditions were modelled. The maximum TN removal efficiency was about 70% and a nitrogen removal flux of 1.25 gN.m[-2].d[-1]. We conclude that mass transfer resistance occurred primarily in the dense, nitrifying layer near the aerated side. The rest of the foam sheet was porous, allowing the advective mass transfer.}, } @article {pmid35348366, year = {2022}, author = {Kebriaei, R and Lev, KL and Shah, RM and Stamper, KC and Holger, DJ and Morrisette, T and Kunz Coyne, AJ and Lehman, SM and Rybak, MJ}, title = {Eradication of Biofilm-Mediated Methicillin-Resistant Staphylococcus aureus Infections In Vitro: Bacteriophage-Antibiotic Combination.}, journal = {Microbiology spectrum}, volume = {10}, number = {2}, pages = {e0041122}, pmid = {35348366}, issn = {2165-0497}, support = {R21 AI163726/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacteriophages ; Biofilms ; *Daptomycin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; }, abstract = {Bacterial biofilms are difficult to eradicate and can complicate many infections by forming on tissues and medical devices. Phage+antibiotic combinations (PAC) may be more active on biofilms than either type of agent alone, but it is difficult to predict which PAC regimens will be reliably effective. To establish a method for screening PAC combinations against Staphylococcus aureus biofilms, we conducted biofilm time-kill analyses (TKA) using various combinations of phage Sb-1 with clinically relevant antibiotics. We determined the activity of PAC against biofilm versus planktonic bacteria and investigated the emergence of resistance during (24 h) exposure to PAC. As expected, fewer treatment regimens were effective against biofilm than planktonic bacteria. In experiments with isogenic strain pairs, we also saw less activity of PACs against DNS-VISA mutants versus their respective parentals. The most effective treatment against both biofilm and planktonic bacteria was the phage+daptomycin+ceftaroline regimen, which met our stringent definition of bactericidal activity (>3 log10 CFU/mL reduction). With the VISA-DNS strain 8015 and DNS strain 684, we detected anti-biofilm synergy between Sb-1 and DAP in the phage+daptomycin regimen (>2 log10 CFU/mL reduction versus best single agent). We did not observe any bacterial resensitization to antibiotics following treatment, but phage resistance was avoided after exposure to PAC regimens for all tested strains. The release of bacterial membrane vesicles tended to be either unaffected or reduced by the various treatment regimens. Interestingly, phage yields from certain biofilm experiments were greater than from similar planktonic experiments, suggesting that Sb-1 might be more efficiently propagated on biofilm. IMPORTANCE Biofilm-associated multidrug-resistant infections pose significant challenges for antibiotic therapy. The extracellular polymeric matrix of biofilms presents an impediment for antibiotic diffusion, facilitating the emergence of multidrug-resistant populations. Some bacteriophages (phages) can move across the biofilm matrix, degrade it, and support antibiotic penetration. However, little is known about how phages and their hosts interact in the biofilm environment or how different phage+antibiotic combinations (PACs) impact biofilms in comparison to the planktonic state of bacteria, though scattered data suggest that phage+antibiotic synergy occurs more readily under biofilm-like conditions. Our results demonstrated that phage Sb-1 can infect MRSA strains both in biofilm and planktonic states and suggested PAC regimens worthy of further investigation as adjuncts to antibiotics.}, } @article {pmid35345952, year = {2022}, author = {Patel, H and Gajjar, D}, title = {Cell adhesion and twitching motility influence strong biofilm formation in Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {38}, number = {3}, pages = {235-249}, doi = {10.1080/08927014.2022.2054703}, pmid = {35345952}, issn = {1029-2454}, mesh = {*Biofilms ; Cell Adhesion ; *Pseudomonas aeruginosa/genetics ; Silicones ; }, abstract = {In the present study, biofilm formation was quantified in UTI isolates of Pseudomonas aeruginosa (n = 22) using the crystal violet assay and was categorized into; strong (n = 16), weak (n = 4), and moderate (n = 2) biofilm producers. Further experiments were done using strong (n = 4) and weak (n = 4) biofilm producers. Biofilm formation was greater in Luria broth followed by natural urine and artificial urine on silicone and silicone-coated latex. Cell adhesion and twitching motility were greater in strong biofilm producers. The presence of thick biofilm with an increased number of dead and total number of cells of strong biofilm producers was observed using CLSM. The concentrations of exopolymeric substances (eDNA, protein, and pel polysaccharide) were high in strong biofilm producers. FEG-SEM visualization of biofilm produced by strong biofilm producers showed more cells encased in thick biofilm matrix than weak ones. Overall results provide evidence for increased cell adhesion and twitching motility in strong biofilm producers.}, } @article {pmid35345543, year = {2021}, author = {Drago, L and Romanò, CL}, title = {Commentary: Dithiothreitol (DTT), When Used as Biofilm Detaching Method to Diagnose Implant-Associated Infections, Does Not Affect Microorganisms' Viability, According to the Current Literature.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {814945}, pmid = {35345543}, issn = {1664-302X}, } @article {pmid35343774, year = {2022}, author = {Iqbal, J and Malviya, N and Gaddy, JA and Zhang, C and Seier, AJ and Haley, KP and Doster, RS and Farfán-García, AE and Gómez-Duarte, OG}, title = {Enteroinvasive Escherichia coli O96:H19 is an Emergent Biofilm-Forming Pathogen.}, journal = {Journal of bacteriology}, volume = {204}, number = {4}, pages = {e0056221}, pmid = {35343774}, issn = {1098-5530}, support = {R01 HD090061/HD/NICHD NIH HHS/United States ; R01 AI134036/AI/NIAID NIH HHS/United States ; K08 AI151100/AI/NIAID NIH HHS/United States ; R01 AI095346/AI/NIAID NIH HHS/United States ; IK2 BX001701/BX/BLRD VA/United States ; }, mesh = {Biofilms ; Child, Preschool ; Escherichia coli/genetics ; *Escherichia coli Infections/microbiology ; *Gastroenteritis/microbiology ; Humans ; Phylogeny ; *Shigella/genetics ; Type III Secretion Systems ; }, abstract = {Enteroinvasive Escherichia coli (EIEC) is a diarrheagenic E. coli pathotype carrying a virulence plasmid that encodes a type III secretion system (TTSS) directly implicated in bacterial cell invasion. Since 2012, EIEC serotype O96:H19 has been recognized in Europe, Colombia, and most recently Uruguay. In addition to the invasion phenotype, the strains isolated from Colombian children with moderate-to-severe gastroenteritis had a strong biofilm formation phenotype, and as a result, they are referred to as biofilm-forming enteroinvasive E. coli (BF-EIEC). The objective of this study was to characterize the biofilm formation phenotype of the BF-EIEC O96:H19 strain 52.1 isolated from a child with moderate-to-severe gastroenteritis in Colombia. Random mutagenesis using Tn5 transposons identified 100 mutants unable to form biofilm; 20 of those had mutations within the pgaABCD operon. Site-directed mutagenesis of pgaB and pgaC confirmed the importance of these genes in N-acetylglucosamine-mediated biofilm formation. Both biofilm formation and TTSS-mediated host cell invasion were associated with host cell damage on the basis of cytotoxic assays comparing the wild type, invasion gene mutants, and biofilm formation mutants. Multilocus sequence typing-based phylogenetic analysis showed that BF-EIEC strain 52.1 does not cluster with classic EIEC serotype strains. Instead, BF-EIEC strain 52.1 clusters with EIEC serotype O96:H19 strains described in Europe and Uruguay. In conclusion, BF-EIEC O96:H19, an emerging pathogen associated with moderate-to-severe acute gastroenteritis in children under 5 years of age in Colombia, invades cells and has a strong biofilm formation capability. Both phenotypes are independently associated with in vitro cell cytotoxicity, and they may explain, at least in part, the higher disease severity reported in Europe and Latin America. IMPORTANCE Enteroinvasive Escherichia coli (EIEC), a close relative of Shigella, is implicated in dysenteric diarrhea. EIEC pathogenicity involves cell invasion mediated by effector proteins delivered by a type III secretion system (TTSS) that disrupt the cell cytoskeleton. These proteins and the VirF global regulator are encoded by a large (>200 kb) invasion plasmid (pINV). This study reports an emergent EIEC possessing a cell invasion phenotype and a strong polysaccharide matrix-mediated biofilm formation phenotype. Both phenotypes contribute to host cell cytotoxicity in vitro and may contribute to the severe disease reported among children and adults in Europe and Latin America.}, } @article {pmid35343438, year = {2022}, author = {Barrasso, K and Chac, D and Debela, MD and Geigel, C and Steenhaut, A and Rivera Seda, A and Dunmire, CN and Harris, JB and Larocque, RC and Midani, FS and Qadri, F and Yan, J and Weil, AA and Ng, WL}, title = {Impact of a human gut microbe on Vibrio cholerae host colonization through biofilm enhancement.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {35343438}, issn = {2050-084X}, support = {DP2 GM146253/GM/NIGMS NIH HHS/United States ; R25 GM066567/GM/NIGMS NIH HHS/United States ; R01 AI137164/AI/NIAID NIH HHS/United States ; T32 DK007664/DK/NIDDK NIH HHS/United States ; R01 AI121337/AI/NIAID NIH HHS/United States ; K08 AI123494/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms ; *Cholera/microbiology ; *Gastrointestinal Microbiome ; Humans ; Mice ; *Vibrio cholerae ; Virulence ; }, abstract = {Recent studies indicate that the human intestinal microbiota could impact the outcome of infection by Vibrio cholerae, the etiological agent of the diarrheal disease cholera. A commensal bacterium, Paracoccus aminovorans, was previously identified in high abundance in stool collected from individuals infected with V. cholerae when compared to stool from uninfected persons. However, if and how P. aminovorans interacts with V. cholerae has not been experimentally determined; moreover, whether any association between this bacterium alters the behaviors of V. cholerae to affect the disease outcome is unclear. Here, we show that P. aminovorans and V. cholerae together form dual-species biofilm structure at the air-liquid interface, with previously uncharacterized novel features. Importantly, the presence of P. aminovorans within the murine small intestine enhances V. cholerae colonization in the same niche that is dependent on the Vibrio exopolysaccharide and other major components of mature V. cholerae biofilm. These studies illustrate that multispecies biofilm formation is a plausible mechanism used by a gut microbe to increase the virulence of the pathogen, and this interaction may alter outcomes in enteric infections.}, } @article {pmid35343028, year = {2022}, author = {Hu, J and Lv, X and Niu, X and Yu, F and Zuo, J and Bao, Y and Yin, H and Huang, C and Nawaz, S and Zhou, W and Jiang, W and Chen, Z and Tu, J and Qi, K and Han, X}, title = {Effect of nutritional and environmental conditions on biofilm formation of avian pathogenic Escherichia coli.}, journal = {Journal of applied microbiology}, volume = {132}, number = {6}, pages = {4236-4251}, doi = {10.1111/jam.15543}, pmid = {35343028}, issn = {1365-2672}, support = {31872483//National Natural Science Foundation of China/ ; 31772707//National Natural Science Foundation of China/ ; 32072829//National Natural Science Foundation of China/ ; 22ZR1475800//The Shanghai Natural Science Foundation of China/ ; 2021J011099//Natural Science Foundation of Fujian Province of China/ ; 2021ZN001//The Research Foundation for Advanced Talents of Longyan University/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Culture Media/pharmacology ; Escherichia coli ; *Escherichia coli Infections/microbiology ; *Escherichia coli Proteins ; Humans ; }, abstract = {AIMS: To study the effects of environmental stress and nutrient conditions on biofilm formation of avian pathogenic Escherichia coli (APEC).

METHODS AND RESULTS: The APEC strain DE17 was used to study biofilm formation under various conditions of environmental stress (including different temperatures, pH, metal ions, and antibiotics) and nutrient conditions (Luria-Bertani [LB] and M9 media, with the addition of different carbohydrates, if necessary). The DE17 biofilm formation ability was strongest at 25°C in LB medium. Compared to incubation at 37°C, three biofilm-related genes (csgD, dgcC, and pfs) were significantly upregulated and two genes (flhC and flhD) were downregulated at 25°C, which resulted in decreased motility. However, biofilm formation was strongest in M9 medium supplemented with glucose at 37°C, and the number of live bacteria was the highest as determined by confocal laser scanning microscopy. The bacteria in the biofilm were surrounded by a thick extracellular matrix, and honeycomb-like or rough surfaces were observed by scanning electron microscopy. Moreover, biofilm formation of the DE17 strain was remarkably inhibited under acidic conditions, whereas neutral and alkaline conditions were more suitable for biofilm formation. Biofilm formation was also inhibited at specific concentrations of cations (Na[+] , K[+] , Ca[2+] , and Mg[2+]) and antibiotics (ampicillin, chloramphenicol, kanamycin, and spectinomycin). The real-time quantitative reverse transcription PCR showed that the transcription levels of biofilm-related genes change under different environmental conditions.

CONCLUSIONS: Nutritional and environmental factors played an important role in DE17 biofilm development. The transcription levels of biofilm-related genes changed under different environmental and nutrient conditions.

The findings suggest that nutritional and environmental factors play an important role in APEC biofilm development. Depending on the different conditions involved in this study, it can serve as a guide to treating biofilm-related infections and to eliminating biofilms from the environment.}, } @article {pmid35341211, year = {2022}, author = {Cai, JN and Choi, HM and Song, KY and Jeon, JG}, title = {The reciprocal interaction between fluoride release of glass ionomers and acid production of Streptococcus mutans biofilm.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {2055267}, pmid = {35341211}, issn = {2000-2297}, abstract = {OBJECTIVES: The aim of this study was to demonstrate the mode of action of glass ionomers (G-Is) against cariogenic biofilms in the slow fluoride release phase by analyzing the reciprocal interaction between fluoride release from G-Is and acid production of Streptococcus mutans biofilm.

METHODS: G-Is discs in the slow fluoride release phase were prepared and 51 h-old S. mutans biofilms were formed on these discs. The interrelationship between the acid production of the biofilm and the fluoride release of the G-Is discs was investigated by analyzing both factors simultaneously during the biofilm formation period. The composition of the 51 h-old biofilms was then examined using microbiological, biochemical, and confocal laser scanning microscopic methods.

RESULTS: Acid production by the cariogenic biofilm, particularly at < pH 5, promotes G-Is fluoride release. Conversely, G-Is fluoride release inhibits the acid production of the cariogenic biofilm. This reciprocal interaction results in the reduction of virulence such as extracellular polysaccharides formation and cariogenic biofilm bio-mass, which may reduce the potential of secondary caries development around G-Is.

CONCLUSIONS: These results suggest that G-Is may play a role in preventing the development of secondary caries during the slow fluoride release phase.}, } @article {pmid35340841, year = {2022}, author = {Schwarz, A and Gaete, M and Nancucheo, I and Villa-Gomez, D and Aybar, M and Sbárbaro, D}, title = {High-Rate Sulfate Removal Coupled to Elemental Sulfur Production in Mining Process Waters Based on Membrane-Biofilm Technology.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {10}, number = {}, pages = {805712}, pmid = {35340841}, issn = {2296-4185}, abstract = {It is anticipated that copper mining output will significantly increase over the next 20 years because of the more intensive use of copper in electricity-related technologies such as for transport and clean power generation, leading to a significant increase in the impacts on water resources if stricter regulations and as a result cleaner mining and processing technologies are not implemented. A key concern of discarded copper production process water is sulfate. In this study we aim to transform sulfate into sulfur in real mining process water. For that, we operate a sequential 2-step membrane biofilm reactor (MBfR) system. We coupled a hydrogenotrophic MBfR (H2-MBfR) for sulfate reduction to an oxidizing MBfR (O2-MBfR) for oxidation of sulfide to elemental sulfur. A key process improvement of the H2-MBfR was online pH control, which led to stable high-rate sulfate removal not limited by biomass accumulation and with H2 supply that was on demand. The H2-MBfR easily adapted to increasing sulfate loads, but the O2-MBfR was difficult to adjust to the varying H2-MBfR outputs, requiring better coupling control. The H2-MBfR achieved high average volumetric sulfate reduction performances of 1.7-3.74 g S/m[3]-d at 92-97% efficiencies, comparable to current high-rate technologies, but without requiring gas recycling and recompression and by minimizing the H2 off-gassing risk. On the other hand, the O2-MBfR reached average volumetric sulfur production rates of 0.7-2.66 g S/m[3]-d at efficiencies of 48-78%. The O2-MBfR needs further optimization by automatizing the gas feed, evaluating the controlled removal of excess biomass and S[0] particles accumulating in the biofilm, and achieving better coupling control between both reactors. Finally, an economic/sustainability evaluation shows that MBfR technology can benefit from the green production of H2 and O2 at operating costs which compare favorably with membrane filtration, without generating residual streams, and with the recovery of valuable elemental sulfur.}, } @article {pmid35340824, year = {2022}, author = {Tian, Y and Zhang, Y and Zhang, M and Chen, X and Lei, L and Hu, T}, title = {Antisense vicR-Loaded Dendritic Mesoporous Silica Nanoparticles Regulate the Biofilm Organization and Cariogenicity of Streptococcus mutans.}, journal = {International journal of nanomedicine}, volume = {17}, number = {}, pages = {1255-1272}, pmid = {35340824}, issn = {1178-2013}, mesh = {Biofilms ; *Dental Caries/prevention & control ; Humans ; *Nanoparticles ; Silicon Dioxide/pharmacology ; Streptococcus mutans/genetics ; }, abstract = {PURPOSE: VicR is the essential response regulator related to the synthesis of exopolysaccharide (EPS) - one of the main cariogenic factors of S. mutans. An antisense vicR RNA (ASvicR) could bind to vicR mRNA, hindering the transcription and translation of the vicR gene. We had constructed a recombinant plasmid containing the ASvicR sequence (plasmid-ASvicR) and proved that it could reduce EPS synthesis, biofilm formation, and cariogenicity. However, the recombinant plasmids are supposed to be protected from enzymatic degradation and possess higher transformation efficiency. The principal objective of the present research was to construct an appropriate vector that can carry and protect the plasmid-ASvicR and investigate the effects of the carried plasmids on the cariogenicity of the S. mutans.

METHODS: Aminated dendritic mesoporous silica nanoparticles (DMSNs-NH2) were synthesized and characterized. The ability of DMSNs-NH2 to carry and preserve the plasmid-ASvicR (DMSNs-NH2-ASvicR) was proved by the loading curve, agarose electrophoresis, DNase I digestion assays, and energy-dispersive spectrometry (EDS) mapping. Transformation assays demonstrated whether the plasmid could enter S. mutans. The effect of DMSNs-NH2-ASvicR on the 12-hour and 24-hour biofilms of S. mutans was evaluated by biofilm formation experiments and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The cytotoxicity of DMSNs-NH2-ASvicR was assessed by CCK-8 and live/dead staining assays. The regulation of DMSNs-NH2-ASvicR on the cariogenicity of S. mutans was also evaluated in vivo.

RESULTS: DMSNs-NH2 could load approximately 92% of plasmid-ASvicR at a mass ratio of 80 and protect most of plasmid-ASvicR from degradation by DNase I. The plasmid-ASvicR loaded on DMSNs-NH2 could be transformed into S. mutans, which down-regulated the expression of the vicR gene, reducing EPS synthesis and biofilm organization of S. mutans. DMSNs-NH2-ASvicR exhibited favorable biocompatibility, laying a foundation for its subsequent biomedical application. In addition, DMSNs-NH2-ASvicR led to decreased caries in vivo.

CONCLUSION: DMSNs-NH2 is a suitable vector of plasmid-ASvicR, and DMSNs-NH2-ASvicR can inhibit biofilm formation, reducing the cariogenicity of S. mutans. These findings reveal that DMSNs-NH2-ASvicR is a promising agent for preventing and treating dental caries.}, } @article {pmid35339968, year = {2022}, author = {Hu, J and Qu, J and Deng, L and Dong, H and Jiang, L and Yu, J and Yue, S and Qian, H and Dai, Q and Qiang, Z}, title = {Metabonomic and transcriptomic modulations of HepG2 cells induced by the CuO-catalyzed formation of disinfection byproducts from biofilm extracellular polymeric substances in copper pipes.}, journal = {Water research}, volume = {216}, number = {}, pages = {118318}, doi = {10.1016/j.watres.2022.118318}, pmid = {35339968}, issn = {1879-2448}, mesh = {Biofilms ; Catalysis ; Chlorine/analysis ; Copper/analysis ; *Disinfectants/analysis ; Disinfection ; Extracellular Polymeric Substance Matrix/chemistry ; Glycerol ; Glycerophospholipids ; Halogenation ; Halogens ; Hep G2 Cells ; Humans ; Transcriptome ; *Water Pollutants, Chemical/analysis ; *Water Purification ; }, abstract = {Cupric oxide (CuO) is able to catalyze the reactions among disinfectant, extracellular polymeric substances (EPS) and bromide (Br[-]) in copper pipes, which may deteriorate the water quality. This study aimed to investigate the metabonomic and transcriptomic modulations of HepG2 cells caused by the CuO-catalyzed formation of disinfection byproducts (DBPs) from EPS. The presence of CuO favored the substitution reactions of chlorine and bromine with EPS, inducing a higher content of total organic halogen (TOX). In addition, DBPs were shifted from chlorinated species to brominated species. A total of 182 differential metabolites (DMs) and 437 differentially expressed genes (DEGs) were identified, which were jointly involved in 38 KEGG pathways. Topology analysis indicates that glycerophospholipid and purine metabolism were disturbed most obviously. During glycerophospholipid metabolism, the differential expression of genes GPATs, AGPATs, LPINs and DGKs impacted the conversion of glycerol-3-phosphate to 2-diacyl-sn-glycerol, which further affected the conversion among phosphatidylcholine, phosphatidylserine and phosphocholines. During purine metabolism, it was mainly the differential expression of genes POLRs, RPAs, RPBs, RPCs, ENTPDs and CDs that impacted the transformation of RNA into guanine-, xanthosine-, inosine- and adenosine monophosphate, which were further successively transformed into their corresponding nucleosides and purines. The study provides an omics perspective to assess the potential adverse effects of overall DBPs formed in copper pipes on human.}, } @article {pmid35337993, year = {2022}, author = {Su, J and Zhang, Q and Huang, W and Song, J and Peng, H and Feng, J and He, J and Zhang, Y and Wei, H}, title = {Transfer of functional microorganism: Regulation of N-acyl-homoserine lactones on the microbial community in aniline-degrading sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {351}, number = {}, pages = {127052}, doi = {10.1016/j.biortech.2022.127052}, pmid = {35337993}, issn = {1873-2976}, mesh = {*Acyl-Butyrolactones ; Aniline Compounds ; Biofilms ; Bioreactors ; Denitrification ; *Microbiota ; Nitrification ; Nitrogen ; Sewage ; Wastewater ; }, abstract = {Due to the inhibition of nitrification from aniline toxicity, exogenous N-acyl-homoserine lactones (AHLs) addition was attempted to enhance nitrogen removal in this work. Two sequencing batch biofilm reactors (SBBRs): S1 (the control) and S2 (C6-HSL and 3-oxo-C8-HSL dosing) were used to treat aniline wastewater. The NH4[+]-N and TN removal rates of S2 were 42.50% and 26.99% higher than S1 in the aerobic phase, respectively. It revealed the nitrogen removal performance of S2 much better than S1. High-throughput sequencing results indicated that many nitrifiers and denitrifiers of S2, such as Nitrosomonas and Thauera, transferred from sludge to biofilm significantly and built closer relationships each other. Overall, main nitrogen removal was contributed by biofilm rather than sludge with the regulation of AHLs. A mild and collaborative environment of biofilms for microorganisms enhanced nitrogen removal. The work provided a new idea for reconciling the contradiction between nitrification and denitrification in aniline wastewater treatment.}, } @article {pmid35337850, year = {2022}, author = {Liu, Z and Li, H and Li, L and Ma, Q and Fang, Z and Wang, H and Lee, Y and Zhao, J and Zhang, H and Chen, W and Lu, W}, title = {Gene-trait matching analysis reveals putative genes involved in Bifidobacterium spp. biofilm formation.}, journal = {Gene}, volume = {826}, number = {}, pages = {146449}, doi = {10.1016/j.gene.2022.146449}, pmid = {35337850}, issn = {1879-0038}, mesh = {Bacteria ; *Bifidobacterium/genetics/metabolism ; Biofilms ; Phenotype ; *Quorum Sensing/genetics ; }, abstract = {Biofilm formation by bacteria represents an adaptation strategy to the environment, and some special genes may lead to a strong biofilm phenotype. In this study, we attempted to find functional genes associated with bifidobacterial biofilm formation. Firstly, we evaluated the biofilm formation ability of bifidobacterial strains from six species, which showed that Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium animalis, Bifidobacterium adolescentis, and Bifidobacterium pseudocatenulatum had biofilm-forming and non-biofilm-forming strains, while all Bifidobacterium bifidum strains could form strong biofilms. Then 48 strains were selected for genome sequencing and comparative analysis. The gene-trait matching analysis revealed that B. bifidum biofilm formation phenotype may associate with their unique genes, involving in stress response, quorum sensing, two components, and peptide synthesis. B. pseudocatenulatum biofilm formation was positively correlated with the eps cluster (rfbX). While no genotype related to the biofilm phenotype was found in B. longum using this analysis, but all contain autoinducer-2 (AI-2) receptor genes. Moreover, luxS, rbsB, rfbX were selected for real-time qPCR analysis, suggesting that their expression are important to biofilm formation. These results indicated that strains carrying certain genes tend to form stronger biofilms than those formed by strains without these genes.}, } @article {pmid35337697, year = {2022}, author = {Trubenová, B and Roizman, D and Moter, A and Rolff, J and Regoes, RR}, title = {Population genetics, biofilm recalcitrance, and antibiotic resistance evolution.}, journal = {Trends in microbiology}, volume = {30}, number = {9}, pages = {841-852}, doi = {10.1016/j.tim.2022.02.005}, pmid = {35337697}, issn = {1878-4380}, mesh = {*Anti-Bacterial Agents/pharmacology ; Bacteria ; *Biofilms ; Drug Resistance, Microbial/genetics ; Genetics, Population ; Microbial Sensitivity Tests ; Plankton ; }, abstract = {Biofilms are communities of bacteria forming high-density sessile colonies. Such a lifestyle comes associated with costs and benefits: while the growth rate of biofilms is often lower than that of their free-living counterparts, this cost is readily repaid once the colony is subjected to antibiotics. Biofilms can grow in antibiotic concentrations a thousand times higher than planktonic bacteria. While numerous mechanisms have been proposed to explain biofilm recalcitrance towards antibiotics, little is yet known about their effect on the evolution of resistance. We synthesize the current understanding of biofilm recalcitrance from a pharmacodynamic and a population genetics perspective. Using the pharmacodynamic framework, we discuss the effects of various mechanisms and show that biofilms can either promote or impede resistance evolution.}, } @article {pmid35336191, year = {2022}, author = {Puhm, M and Ainelo, H and Kivisaar, M and Teras, R}, title = {Tryptone in Growth Media Enhances Pseudomonas putida Biofilm.}, journal = {Microorganisms}, volume = {10}, number = {3}, pages = {}, pmid = {35336191}, issn = {2076-2607}, support = {PRG707//Estonian Research Council/ ; }, abstract = {Extracellular factors and growth conditions can affect the formation and development of bacterial biofilms. The biofilm of Pseudomonas putida has been studied for decades, but so far, little attention has been paid to the components of the medium that may affect the biofilm development in a closed system. It is known that Fis strongly enhances biofilm in complete LB medium. However, this is not the case in the defined M9 medium, which led us to question why the bacterium behaves differently in these two media. Detailed analysis of the individual medium components revealed that tryptone as the LB proteinaceous component maintains biofilm in its older stages. Although the growth parameters of planktonic cells were similar in the media containing tryptone or an equivalent concentration of amino acids, only the tryptone had a positive effect on the mature biofilm of the wild type strain of P. putida. Thus, the peptides in the environment may influence mature biofilm as a structural factor and not only as an energy source. Testing the effect of other biopolymers on biofilm formation showed variable results even for polymers with a similar charge, indicating that biopolymers can affect P. putida biofilm through a number of bacterial factors.}, } @article {pmid35336161, year = {2022}, author = {Moore, K and Gupta, N and Gupta, TT and Patel, K and Brooks, JR and Sullivan, A and Litsky, AS and Stoodley, P}, title = {Mapping Bacterial Biofilm on Features of Orthopedic Implants In Vitro.}, journal = {Microorganisms}, volume = {10}, number = {3}, pages = {}, pmid = {35336161}, issn = {2076-2607}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R01GM124436/NH/NIH HHS/United States ; }, abstract = {Implant-associated infection is a major complication of orthopedic surgery. One of the most common organisms identified in periprosthetic joint infections is Staphylococcus aureus, a biofilm-forming pathogen. Orthopedic implants are composed of a variety of materials, such as titanium, polyethylene and stainless steel, which are at risk for colonization by bacterial biofilms. Little is known about how larger surface features of orthopedic hardware (such as ridges, holes, edges, etc.) influence biofilm formation and attachment. To study how biofilms might form on actual components, we submerged multiple orthopedic implants of various shapes, sizes, roughness and material type in brain heart infusion broth inoculated with Staphylococcus aureus SAP231, a bioluminescent USA300 strain. Implants were incubated for 72 h with daily media exchanges. After incubation, implants were imaged using an in vitro imaging system (IVIS) and the metabolic signal produced by biofilms was quantified by image analysis. Scanning electron microscopy was then used to image different areas of the implants to complement the IVIS imaging. Rough surfaces had the greatest luminescence compared to edges or smooth surfaces on a single implant and across all implants when the images were merged. The luminescence of edges was also significantly greater than smooth surfaces. These data suggest implant roughness, as well as large-scale surface features, may be at greater risk of biofilm colonization.}, } @article {pmid35336113, year = {2022}, author = {Rossi, E and Leccese, G and Baldelli, V and Bibi, A and Scalone, E and Camilloni, C and Paroni, M and Landini, P}, title = {Inactivation of the Pyrimidine Biosynthesis pyrD Gene Negatively Affects Biofilm Formation and Virulence Determinants in the Crohn's Disease-Associated Adherent Invasive Escherichia coli LF82 Strain.}, journal = {Microorganisms}, volume = {10}, number = {3}, pages = {}, pmid = {35336113}, issn = {2076-2607}, support = {2017-0816//Fondazione Cariplo/ ; }, abstract = {In Crohn's disease (CD) patients, the adherent-invasive Escherichia coli (AIEC) pathovar contributes to the chronic inflammation typical of the disease via its ability to invade gut epithelial cells and to survive in macrophages. We show that, in the AIEC strain LF82, inactivation of the pyrD gene, encoding dihydroorotate dehydrogenase (DHOD), an enzyme of the de novo pyrimidine biosynthetic pathway, completely abolished its ability of to grow in a macrophage environment-mimicking culture medium. In addition, pyrD inactivation reduced flagellar motility and strongly affected biofilm formation by downregulating transcription of both type 1 fimbriae and curli subunit genes. Thus, the pyrD gene appears to be essential for several cellular processes involved in AIEC virulence. Interestingly, vidofludimus (VF), a DHOD inhibitor, has been proposed as an effective drug in CD treatment. Despite displaying a potentially similar binding mode for both human and E. coli DHOD in computational molecular docking experiments, VF showed no activity on either growth or virulence-related processes in LF82. Altogether, our results suggest that the crucial role played by the pyrD gene in AIEC virulence, and the presence of structural differences between E. coli and human DHOD allowing for the design of specific inhibitors, make E. coli DHOD a promising target for therapeutical strategies aiming at counteracting chronic inflammation in CD by acting selectively on its bacterial triggers.}, } @article {pmid35335670, year = {2022}, author = {Chitlapilly Dass, S and Wang, R}, title = {Biofilm through the Looking Glass: A Microbial Food Safety Perspective.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35335670}, issn = {2076-0817}, support = {USDA-NIFA 2020-67017-30776.//United States Department of Agriculture/ ; }, abstract = {Food-processing facilities harbor a wide diversity of microorganisms that persist and interact in multispecies biofilms, which could provide an ecological niche for pathogens to better colonize and gain tolerance against sanitization. Biofilm formation by foodborne pathogens is a serious threat to food safety and public health. Biofilms are formed in an environment through synergistic interactions within the microbial community through mutual adaptive response to their long-term coexistence. Mixed-species biofilms are more tolerant to sanitizers than single-species biofilms or their planktonic equivalents. Hence, there is a need to explore how multispecies biofilms help in protecting the foodborne pathogen from common sanitizers and disseminate biofilm cells from hotspots and contaminate food products. This knowledge will help in designing microbial interventions to mitigate foodborne pathogens in the processing environment. As the global need for safe, high-quality, and nutritious food increases, it is vital to study foodborne pathogen behavior and engineer new interventions that safeguard food from contamination with pathogens. This review focuses on the potential food safety issues associated with biofilms in the food-processing environment.}, } @article {pmid35335647, year = {2022}, author = {Zhang, L and Ma, L and Yang, Q and Liu, Y and Ai, X and Dong, J}, title = {Sanguinarine Protects Channel Catfish against Aeromonas hydrophila Infection by Inhibiting Aerolysin and Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35335647}, issn = {2076-0817}, support = {31702368//National Natural Science Foundation of China/ ; }, abstract = {Aeromonas hydrophila is a pathogenic bacterium that can cause serious infections both in humans and aquatic animals. Antibiotics are the main approach for fighting against the pathogen. However, the emergence of antibiotic resistance has resulted in treatment failure. Therefore, drugs with novel strategies need to be developed. Quorum sensing has been recognized as a promising method for identifying anti-virulence drugs against bacterial infections. The aim of this study was to identify novel drugs targeting quorum sensing of A. hydrophila as alternatives of antibiotics in aquaculture. Thus, hemolytic activity, biofilm formation, qPCR and experimental therapeutics assays were conducted. The results showed that sanguinarine inhibited the growth of A. hydrophila at concentrations higher than 16 μg/mL, but the production of aerolysin and biofilm formation was significantly inhibited at sub-inhibitory concentrations by disrupting the quorum sensing system. Cell viability results showed that sanguinarine could provide protection for A549 cells from aerolysin-induced cell injury. In addition, the mortality of channel catfish administered with sanguinarine at a dosage of 20 mg/kg decreased to 40%, which showed a significant decrease compared with fish in positive group. Taken together, these findings demonstrated that anti-virulence strategies can be a powerful weapon for fighting against bacterial pathogens and sanguinarine appears to be a promising candidate in the treatment of A. hydrophila infections.}, } @article {pmid35335624, year = {2022}, author = {Tuon, FF and Dantas, LR and Suss, PH and Tasca Ribeiro, VS}, title = {Pathogenesis of the Pseudomonas aeruginosa Biofilm: A Review.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35335624}, issn = {2076-0817}, abstract = {Pseudomonas aeruginosa is associated with several human infections, mainly related to healthcare services. In the hospital, it is associated with resistance to several antibiotics, which poses a great challenge to therapy. However, one of the biggest challenges in treating P. aeruginosa infections is that related to biofilms. The complex structure of the P. aeruginosa biofilm contributes an additional factor to the pathogenicity of this microorganism, leading to therapeutic failure, in addition to escape from the immune system, and generating chronic infections that are difficult to eradicate. In this review, we address several molecular aspects of the pathogenicity of P. aeruginosa biofilms.}, } @article {pmid35334296, year = {2022}, author = {Hernández-Eligio, A and Huerta-Miranda, GA and Martínez-Bahena, S and Castrejón-López, D and Miranda-Hernández, M and Juárez, K}, title = {GSU1771 regulates extracellular electron transfer and electroactive biofilm formation in Geobacter sulfurreducens: Genetic and electrochemical characterization.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {145}, number = {}, pages = {108101}, doi = {10.1016/j.bioelechem.2022.108101}, pmid = {35334296}, issn = {1878-562X}, mesh = {Bacterial Proteins/*metabolism ; Biofilms ; Cytochromes ; Electron Transport ; Electrons ; *Ferric Compounds/metabolism ; *Geobacter/metabolism ; Oxidation-Reduction ; Oxides ; }, abstract = {Type IV pili and the >100c-type cytochromes in Geobacter sulfurreducens are essential for extracellular electron transfer (EET) towards metal oxides and electrodes. A previous report about a mutation in the gsu1771 gene indicated an enhanced reduction of insoluble Fe(III) oxides coupled with increased pilA expression. Herein, a marker-free gsu1771-deficient mutant was constructed and characterized to assess the role of this regulator in EET and the formation of electroactive biofilms. Deleting this gene delayed microbial growth in the acetate/fumarate media (electron donor and acceptor, respectively). However, this mutant reduced soluble and insoluble Fe(III) oxides more efficiently. Heme staining, western blot, and RT-qPCR analyses demonstrated that GSU1771 regulates the transcription of several genes (including pilA) and many c-type cytochromes involved in EET, suggesting the broad regulatory role of this protein. DNA-protein binding assays indicated that GSU1771 directly regulates the transcription of pilA, omcE, omcS, and omcZ. Additionally, gsu1771-deficient mutant biofilms are thicker than wild-type strains. Electrochemical studies revealed that the current produced by this biofilm was markedly higher than the wild-type strains (approximately 100-fold). Thus, demonstrating the role of GSU1771 in the EET pathway and establishing a methodology to develop highly electroactive G. sulfurreducens mutants.}, } @article {pmid35332728, year = {2022}, author = {Lin, YW and Jing, ML and Li, YQ and Zhou, XD}, title = {[Inhibitory Effects of Nicotinamide on Streptococcus mutans Growth and Biofilm Formation].}, journal = {Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition}, volume = {53}, number = {2}, pages = {268-273}, doi = {10.12182/20220360205}, pmid = {35332728}, issn = {1672-173X}, mesh = {Biofilms ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; *Niacinamide/pharmacology ; *Streptococcus mutans ; }, abstract = {OBJECTIVE: To explore the effects of nicotinamide (NAM) on the growth, biofilm formation and exopolysaccharides (EPS) production of Streptococcus mutans.

METHODS: The minimum inhibitory concentration (MIC) of NAM on S. mutanswas determined by the planktonic bacterial susceptibility assay. The NAM mass concentrations were set as 1/2 MIC, 1/4 MIC and 1/8 MIC for hree separate treatment groups. Culture medium without NAM was used in the negative control group and culture medium containing 0.1 mg/mL NaF was used for the positive control group (except for the scanning electron microscopy). The growth curves of S. mutans under different NAM concentrations were drawn. Crystal violet assay and anthrone-sulfuric acid method were used to explore the effects of NAM on S. mutans biofilm formation and water-insoluble EPS production, respectively. The morphology and structure of S. mutansplanktons and biofilms after NAM treatment were observed by scanning electron microscopy.

RESULTS: The MIC of NAM on S. mutans was 32 μg/μL. After 16 μg/μL (1/2 MIC), 8 μg/μL (1/4 MIC) and 4 μg/μL (1/8 MIC) NAM treatments, S. mutans growth and biofilm formation were inhibited, with the 16 μg/μL NAM group displaying the most significant inhibitory effects. The synthesis of EPS decreased significantly in the 16 μg/μL and 8 μg/μL NAM groups in comparison with that of the negative control group (P<0.05). Under scanning electron microscope, the cell length of S. mutans was shortened, the cell width was extended, and the length/width ratio was decreased, showing significant difference when comparing the 16 μg/μL and 8 μg/μL NAM groups with the negative control group (P<0.05).

CONCLUSION: Under the influence of NAM at certain concenrations, the growth, biofilm formation, and EPS synthesis of S. mutanswere inhibited.}, } @article {pmid35332241, year = {2022}, author = {Piri-Gharaghie, T and Jegargoshe-Shirin, N and Saremi-Nouri, S and Khademhosseini, SH and Hoseinnezhad-Lazarjani, E and Mousavi, A and Kabiri, H and Rajaei, N and Riahi, A and Farhadi-Biregani, A and Fatehi-Ghahfarokhi, S}, title = {Effects of Imipenem-containing Niosome nanoparticles against high prevalence methicillin-resistant Staphylococcus Epidermidis biofilm formed.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {5140}, pmid = {35332241}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Imipenem/pharmacology ; Liposomes/pharmacology ; Methicillin Resistance ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Nanoparticles ; Prevalence ; Staphylococcus epidermidis ; }, abstract = {We aim to assess the antibacterial and anti-biofilm properties of Niosome-encapsulated Imipenem. After isolating Staphylococcus epidermidis isolates and determining their microbial sensitivity, their ability to form biofilms was examined using plate microtiter assay. Various formulations of Niosome-encapsulated Imipenem were prepared using the thin-film hydration method, Minimum Biofilm Inhibitory Concentration (MBIC) and Minimum Inhibitory Concentration (MIC) were determined, and biofilm genes expression was examined. Drug formulations' toxicity effect on HDF cells were determined using MTT assay. Out of the 162 separated S. epidermidis, 106 were resistant to methicillin. 87 MRSE isolates were vancomycin-resistant, all of which could form biofilms. The F1 formulation of niosomal Imipenem with a size of 192.3 ± 5.84 and an encapsulation index of 79.36 ± 1.14 was detected, which prevented biofilm growth with a BGI index of 69% and reduced icaD, FnbA, EbpS biofilms' expression with P ≤ 0.001 in addition to reducing MBIC and MIC by 4-6 times. Interestingly, F1 formulation of niosomal Imipenem indicated cell viability over 90% at all tested concentrations. The results of the present study indicate that Niosome-encapsulated Imipenem reduces the resistance of MRSE to antibiotics in addition to increasing its anti-biofilm and antibiotic activity, and could prove useful as a new strategy for drug delivery.}, } @article {pmid35330242, year = {2022}, author = {Sass, G and Scherpe, L and Martinez, M and Marsh, JJ and Stevens, DA}, title = {Metrics of Antifungal Effects of Ciprofloxacin on Aspergillus fumigatus Planktonic Growth and Biofilm Metabolism; Effects of Iron and Siderophores.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {3}, pages = {}, pmid = {35330242}, issn = {2309-608X}, support = {8201//Foundation for Research in Infectious Diseases/ ; }, abstract = {Pseudomonas aeruginosa and Aspergillus fumigatus frequently coexist in the airways of immunocompromised patients or individuals with cystic fibrosis. Ciprofloxacin (CIP) is a synthetic quinolone antibiotic commonly used to treat bacterial infections, such as those produced by Pseudomonas aeruginosa. CIP binds iron, and it is unclear what effect this complex would have on the mycobiome. The effects of CIP on Aspergillus were dependent on the iron levels present, and on the presence of Aspergillus siderophores. We found that CIP alone stimulated wildtype planktonic growth, but not biofilm metabolism. At high concentrations, CIP antagonized a profungal effect of iron on wildtype Aspergillus metabolism, presumably owing to iron chelation. CIP interfered with the metabolism and growth of an Aspergillus siderophore mutant, with the effect on metabolism being antagonized by iron. CIP acted synergistically with iron on the growth of the mutant, and, to a lesser extent, the wildtype. In summary, CIP can increase fungal growth or affect fungal metabolism, depending on the local iron concentration and available siderophores. Therefore, high local CIP concentrations during treatment of Pseudomonas-Aspergillus co-infections may increase the fungal burden.}, } @article {pmid35329724, year = {2022}, author = {Hirai, N and Horii, M and Kogo, T and Ogawa, A and Kuroda, D and Kanematsu, H and Nakata, J and Katsuyama, S}, title = {Simple Methods for Evaluating Acid Permeation and Biofilm Formation Behaviors on Polysiloxane Films.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {6}, pages = {}, pmid = {35329724}, issn = {1996-1944}, abstract = {The sulfuric acid permeation and biofilm formation behaviors of polysiloxane films have been investigated, and simple methods for evaluating the sulfuric acid permeation and biofilm formation behaviors have been proposed in this paper. The polysiloxane films used in these experiments were practically impermeable to the aqueous sulfuric acid solution, and the amount of biofilm formation varied depending on the composition of the films. Further, the amount of sulfuric acid permeation can be estimated by measuring the polarization curves of polysiloxane films with different thicknesses formed on iron electrodes. By measuring the adhesion work of pure water and simulated biofilm droplets on polysiloxane films of different compositions, we can estimate the resistance of biofilm formation on the polysiloxane films.}, } @article {pmid35329591, year = {2022}, author = {Hu, H and Clothier, N and Jacombs, A and Mckay, K and Deva, AK and Vickery, K}, title = {Biofilm on Toothbrushes of Children with Cystic Fibrosis: A Potential Source of Lung Re-Infection after Antibiotic Treatment?.}, journal = {Materials (Basel, Switzerland)}, volume = {15}, number = {6}, pages = {}, pmid = {35329591}, issn = {1996-1944}, abstract = {Frequent recurrent lung infections result in irreversible lung damage in children with cystic fibrosis (CF). This study aimed to determine if toothbrushes contain biofilms of pathogens, and act as potential reservoirs for lung re-infection following antibiotic treatment of acute exacerbations. Toothbrushes were collected from children with CF of lung infection before, during and after antibiotic treatment. Toothbrushes were rinsed with sterile saline and cultured. Bacterial isolates from toothbrushes were identified by 16s rRNA gene sequencing and compared with isolates from a sputum sample of the same patient. Scanning electron microscopy (SEM) was used to visually confirm the presence of bacterial biofilms and confocal laser scanning microscopy (CLSM) combined with Live/Dead stain to confirm bacterial viability. Large numbers of bacteria and biofilms were present on all toothbrushes. SEM confirmed the presence of biofilms and CLSM confirmed bacterial viability on all toothbrushes. Pathogens identified on toothbrushes from children before and during antibiotics treatment were in concordance with the species found in sputum samples. Pseudomonas aeruginosa and Staphylococcus aureus was able to be cultured from children's toothbrushes despite antibiotic treatment. Toothbrushes were shown to be contaminated with viable pathogens and biofilms before and during antibiotic treatment and could be a potential source of lung re-infections.}, } @article {pmid35329426, year = {2022}, author = {Gambino, E and Maione, A and Guida, M and Albarano, L and Carraturo, F and Galdiero, E and Di Onofrio, V}, title = {Evaluation of the Pathogenic-Mixed Biofilm Formation of Pseudomonas aeruginosa/Staphylococcus aureus and Treatment with Limonene on Three Different Materials by a Dynamic Model.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {6}, pages = {}, pmid = {35329426}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Limonene/pharmacology ; Microbial Sensitivity Tests ; *Pseudomonas aeruginosa/genetics ; Stainless Steel/pharmacology ; *Staphylococcus aureus/genetics ; }, abstract = {BACKGROUND: Biofilms have been found growing on implantable medical devices. This can lead to persistent clinical infections. The highly antibiotic-resistant property of biofilms necessitates the search for both potent antimicrobial agents and novel antibiofilm strategies. Natural product-based anti-biofilm agents were found to be as efficient as chemically synthesized counterparts with fewer side effects. In the present study, the effects of limonene as an antibiofilm agent were evaluated on Pseudomonas aeruginosa and Staphylococcus aureus biofilm formed on different surfaces using the CDC model system in continuous flow. The flgK gene and the pilA gene expression in P. aeruginosa, and the icaA gene and eno gene in S. aureus, which could be considered as efficient resistance markers, were studied.

METHODS: Mono- and dual-species biofilms were grown on polycarbonate, polypropylene, and stainless-steel coupons in a CDC biofilm reactor (Biosurface Technologies, Bozeman, MT, USA). To evaluate the ability of limonene to inhibit and eradicate biofilm, a sub-MIC concentration (10 mL/L) was tested. The gene expression of P. aeruginosa and S. aureus was detected by SYBR Green quantitative Real-Time PCR assay (Meridiana Bioline, Brisbane, Australia).

RESULTS: The limonene added during the formation of biofilms at sub-MIC concentrations works very well in inhibiting biofilms on all three materials, reducing their growth by about 2 logs. Of the same order of magnitude is the ability of limonene to eradicate both mono- and polymicrobial mature biofilms on all three materials. Greater efficacy was observed in the polymicrobial biofilm on steel coupons. The expression of some genes related to the virulence of the two microorganisms was differently detected in mono- and polymicrobial biofilm.

CONCLUSIONS: These data showed that the limonene treatment expressed different levels of biofilm-forming genes, especially when both types of strains alone and together grew on different surfaces. Our findings showed that limonene treatment is also very efficient when biofilm has been grown under shear stress causing significant and irreversible damage to the biofilm structure. The effectiveness of the sanitation procedures can be optimized by applying antimicrobial combinations with natural compounds (e.g., limonene).}, } @article {pmid35328711, year = {2022}, author = {Loke, MF and Yadav, I and Lim, TK and van der Maarel, JRC and Sham, LT and Chow, VT}, title = {SARS-CoV-2 Spike Protein and Mouse Coronavirus Inhibit Biofilm Formation by Streptococcus pneumoniae and Staphylococcus aureus.}, journal = {International journal of molecular sciences}, volume = {23}, number = {6}, pages = {}, pmid = {35328711}, issn = {1422-0067}, support = {N571000016001//National University of Singapore/ ; }, mesh = {Animals ; *Antibiosis ; *Biofilms ; Coinfection ; Coronavirus/*physiology ; Gene Expression Regulation, Bacterial ; Humans ; Mice ; Microbial Interactions ; SARS-CoV-2/*physiology ; Serogroup ; Spike Glycoprotein, Coronavirus/*metabolism ; Staphylococcus aureus/classification/*physiology ; Streptococcus pneumoniae/classification/*physiology ; }, abstract = {The presence of co-infections or superinfections with bacterial pathogens in COVID-19 patients is associated with poor outcomes, including increased morbidity and mortality. We hypothesized that SARS-CoV-2 and its components interact with the biofilms generated by commensal bacteria, which may contribute to co-infections. This study employed crystal violet staining and particle-tracking microrheology to characterize the formation of biofilms by Streptococcus pneumoniae and Staphylococcus aureus that commonly cause secondary bacterial pneumonia. Microrheology analyses suggested that these biofilms were inhomogeneous soft solids, consistent with their dynamic characteristics. Biofilm formation by both bacteria was significantly inhibited by co-incubation with recombinant SARS-CoV-2 spike S1 subunit and both S1 + S2 subunits, but not with S2 extracellular domain nor nucleocapsid protein. Addition of spike S1 and S2 antibodies to spike protein could partially restore bacterial biofilm production. Furthermore, biofilm formation in vitro was also compromised by live murine hepatitis virus, a related beta-coronavirus. Supporting data from LC-MS-based proteomics of spike-biofilm interactions revealed differential expression of proteins involved in quorum sensing and biofilm maturation, such as the AI-2E family transporter and LuxS, a key enzyme for AI-2 biosynthesis. Our findings suggest that these opportunistic pathogens may egress from biofilms to resume a more virulent planktonic lifestyle during coronavirus infections. The dispersion of pathogens from biofilms may culminate in potentially severe secondary infections with poor prognosis. Further detailed investigations are warranted to establish bacterial biofilms as risk factors for secondary pneumonia in COVID-19 patients.}, } @article {pmid35328675, year = {2022}, author = {Benthien, H and Fresenborg, B and Pätzold, L and Elhawy, MI and Huc-Brandt, S and Beisswenger, C and Krasteva-Christ, G and Becker, SL and Molle, V and Knobloch, JK and Bischoff, M}, title = {The Transcription Factor SpoVG Is of Major Importance for Biofilm Formation of Staphylococcus epidermidis under In Vitro Conditions, but Dispensable for In Vivo Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {23}, number = {6}, pages = {}, pmid = {35328675}, issn = {1422-0067}, support = {German Egyptian Research Long-Term Scholarship Program//Egyptian Ministry of Higher Education and Scientific Research (MHESR) and the German Academic Exchange Service (DAAD)/ ; Open Access Publishing//DFG and Saarland University/ ; }, mesh = {Animals ; Bacterial Proteins/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Iron-Dextran Complex ; Mice ; Polysaccharides, Bacterial/metabolism ; *Staphylococcus epidermidis/metabolism ; *Transcription Factors/metabolism ; }, abstract = {Staphylococcus epidermidis is a common cause of device related infections on which pathogens form biofilms (i.e., multilayered cell populations embedded in an extracellular matrix). Here, we report that the transcription factor SpoVG is essential for the capacity of S. epidermidis to form such biofilms on artificial surfaces under in vitro conditions. Inactivation of spoVG in the polysaccharide intercellular adhesin (PIA) producing S. epidermidis strain 1457 yielded a mutant that, unlike its parental strain, failed to produce a clear biofilm in a microtiter plate-based static biofilm assay. A decreased biofilm formation capacity was also observed when 1457 ΔspoVG cells were co-cultured with polyurethane-based peripheral venous catheter fragments under dynamic conditions, while the cis-complemented 1457 ΔspoVG::spoVG derivative formed biofilms comparable to the levels seen with the wild-type. Transcriptional studies demonstrated that the deletion of spoVG significantly altered the expression of the intercellular adhesion (ica) locus by upregulating the transcription of the ica operon repressor icaR and down-regulating the transcription of icaADBC. Electrophoretic mobility shift assays (EMSA) revealed an interaction between SpoVG and the icaA-icaR intergenic region, suggesting SpoVG to promote biofilm formation of S. epidermidis by modulating ica expression. However, when mice were challenged with the 1457 ΔspoVG mutant in a foreign body infection model, only marginal differences in biomasses produced on the infected catheter fragments between the mutant and the parental strain were observed. These findings suggest that SpoVG is critical for the PIA-dependent biofilm formation of S. epidermis under in vitro conditions, but is largely dispensable for biofilm formation of this skin commensal under in vivo conditions.}, } @article {pmid35328451, year = {2022}, author = {Shin, SH and Ye, MK and Lee, DW and Chae, MH}, title = {Asian Sand Dust Particles Enhance the Development of Aspergillus fumigatus Biofilm on Nasal Epithelial Cells.}, journal = {International journal of molecular sciences}, volume = {23}, number = {6}, pages = {}, pmid = {35328451}, issn = {1422-0067}, support = {2019R1F1A1047757//National Research Foundation of Korea/ ; }, mesh = {*Aspergillus fumigatus/metabolism ; Biofilms ; Concanavalin A/pharmacology ; Dust ; Epithelial Cells/metabolism ; Gentian Violet/metabolism/pharmacology ; Inflammation Mediators/metabolism ; Interleukin-6/metabolism ; Interleukin-8/metabolism ; Nasal Mucosa/metabolism ; *Sand ; }, abstract = {BACKGROUND: Asian sand dust (ASD) and Aspergillus fumigatus are known risk factors for airway mucosal inflammatory diseases. Bacterial and fungal biofilms commonly coexist in chronic rhinosinusitis and fungus balls. We evaluated the effects of ASD on the development of A. fumigatus biofilm formation on nasal epithelial cells.

METHODS: Primary nasal epithelial cells were cultured with A. fumigatus conidia with or without ASD for 72 h. The production of interleukin (IL)-6, IL-8, and transforming growth factor (TGF)-β1 from nasal epithelial cells was determined by the enzyme-linked immunosorbent assay. The effects of ASD on A. fumigatus biofilm formation were determined using crystal violet, concanavalin A, safranin staining, and confocal scanning laser microscopy.

RESULTS: ASD and A. fumigatus significantly enhanced the production of IL-6 and IL-8 from nasal epithelial cells. By coculturing A. fumigatus with ASD, the dry weight and safranin staining of the fungal biofilms significantly increased in a time-dependent manner. However, the increased level of crystal violet and concanavalin A stain decreased after 72 h of incubation.

CONCLUSIONS: ASD and A. fumigatus induced the production of inflammatory chemical mediators from nasal epithelial cells. The exposure of A. fumigatus to ASD enhanced the formation of biofilms. The coexistence of ASD and A. fumigatus may increase the development of fungal biofilms and fungal inflammatory diseases in the sinonasal mucosa.}, } @article {pmid35326877, year = {2022}, author = {Braga, AS and Abdelbary, MMH and Kim, RR and Melo, FPSR and Saldanha, LL and Dokkedal, AL and Conrads, G and Esteves-Oliveira, M and Magalhães, AC}, title = {The Effect of Toothpastes Containing Natural Extracts on Bacterial Species of a Microcosm Biofilm and on Enamel Caries Development.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35326877}, issn = {2079-6382}, support = {2017/00556-0//São Paulo Research Foundation/ ; 2017/17249-2//São Paulo Research Foundation/ ; 2018/26506-1//São Paulo Research Foundation/ ; 2019/21797-0//The São Paulo Research Foundation/ ; }, abstract = {This study investigated the effects of herbal toothpaste on bacterial counts and enamel demineralization. Thirty-six bovine enamel samples were exposed to a microcosm biofilm using human saliva and McBain saliva (0.2% sucrose) for 5 days at 37 °C and first incubated anaerobically, then aerobically-capnophilically. The following experimental toothpaste slurries (2 × 2 min/day) were applied: (1) Vochysia tucanorum (10 mg/g); (2) Myrcia bella (5 mg/g); (3) Matricaria chamomilla (80 mg/g); (4) Myrrha and propolis toothpaste (commercial); (5) fluoride (F) and triclosan (1450 ppm F), 0.3% triclosan and sorbitol (Colgate[®], positive control); (6) placebo (negative control). The pH of the medium was measured, bacteria were analyzed using quantitative polymerase chain reaction, and enamel demineralization was quantified using transverse microradiography. The total bacterial count was reduced by toothpaste containing Myrcia bella, Matricaria chamomilla, fluoride, and triclosan (commercial) compared to the placebo. As far as assessable, Myrcia bella, Matricaria chamomilla, and Myrrha and propolis (commercial) inhibited the outgrowth of S. mutans, while Lactobacillus spp. were reduced/eliminated by all toothpastes except Vochysia tucanorum. Mineral loss and lesion depth were significantly reduced by all toothpastes (total: 1423.6 ± 115.2 vol% × μm; 57.3 ± 9.8 μm) compared to the placebo (2420.0 ± 626.0 vol% × μm; 108.9 ± 21.17 μm). Herbal toothpastes were able to reduce enamel demineralization.}, } @article {pmid35326855, year = {2022}, author = {Lev, K and Kunz Coyne, AJ and Kebriaei, R and Morrisette, T and Stamper, K and Holger, DJ and Canfield, GS and Duerkop, BA and Arias, CA and Rybak, MJ}, title = {Evaluation of Bacteriophage-Antibiotic Combination Therapy for Biofilm-Embedded MDR Enterococcus faecium.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35326855}, issn = {2079-6382}, support = {P01 AI152999/AI/NIAID NIH HHS/United States ; R01 AI121400/AI/NIAID NIH HHS/United States ; R01 AI141479/AI/NIAID NIH HHS/United States ; R01 AI148342/AI/NIAID NIH HHS/United States ; }, abstract = {Multidrug-resistant (MDR) Enterococcus faecium is a challenging pathogen known to cause biofilm-mediated infections with limited effective therapeutic options. Lytic bacteriophages target, infect, and lyse specific bacterial cells and have anti-biofilm activity, making them a possible treatment option. Here, we examine two biofilm-producing clinical E. faecium strains, daptomycin (DAP)-resistant R497 and DAP-susceptible dose-dependent (SDD) HOU503, with initial susceptibility to E. faecium bacteriophage 113 (ATCC 19950-B1). An initial synergy screening was performed with modified checkerboard MIC assays developed by our laboratory to efficiently screen for antibiotic and phage synergy, including at very low phage multiplicity of infection (MOI). The data were compared by one-way ANOVA and Tukey (HSD) tests. In 24 h time kill analyses (TKA), combinations with phage-DAP-ampicillin (AMP), phage-DAP-ceftaroline (CPT), and phage-DAP-ertapenem (ERT) were synergistic and bactericidal compared to any single agent (ANOVA range of mean differences 3.34 to 3.84 log10 CFU/mL; p < 0.001). Furthermore, phage-DAP-AMP and phage-DAP-CPT prevented the emergence of DAP and phage resistance. With HOU503, the combination of phage-DAP-AMP showed the best killing effect, followed closely by phage-DAP-CPT; both showed bactericidal and synergistic effects compared to any single agent (ANOVA range of mean differences 3.99 to 4.08 log10 CFU/mL; p < 0.001).}, } @article {pmid35326851, year = {2022}, author = {Abdel-Shafi, S and El-Serwy, H and El-Zawahry, Y and Zaki, M and Sitohy, B and Sitohy, M}, title = {The Association between icaA and icaB Genes, Antibiotic Resistance and Biofilm Formation in Clinical Isolates of Staphylococci spp.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35326851}, issn = {2079-6382}, abstract = {Sixty-six (66) Staphylococcus bacterial isolates were withdrawn from separate clinical samples of hospitalized patients with various clinical infections. Conventional bacteriological tests identified the species of all isolates, and standard microbiological techniques differentiated them into CoPS or CoNS. Their biofilm development was followed by an analysis via the MTP (microtiter tissue culture plates) technique, and we then investigated the presence/absence of icaA and icaB, which were qualified in the top-30 potent biofilm-forming isolates. Thirteen isolates (46.7%) showed the presence of one gene, six (20%) isolates exhibited the two genes, while ten (33.3%) had neither of them. The formation of staphylococci biofilms in the absence of ica genes may be related to the presence of other biofilm formation ica-independent mechanisms. CoPS was the most abundant species among the total population. S. aureus was the sole representative of CoPS, while S. epidermidis was the most abundant form of CoNS. Antibiotic resistance was developing against the most frequently used antimicrobial drugs, while vancomycin was the least-resisted drug. The totality of the strong and medium-strength film-forming isolates represented the majority proportion (80%) of the total investigated clinical samples. The biochemical pattern CoPS is associated with antibiotic resistance and biofilm formation and can be an alarming indicator of potential antibiotic resistance.}, } @article {pmid35326843, year = {2022}, author = {Alzahrani, OM and Fayez, M and Alswat, AS and Alkafafy, M and Mahmoud, SF and Al-Marri, T and Almuslem, A and Ashfaq, H and Yusuf, S}, title = {Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {3}, pages = {}, pmid = {35326843}, issn = {2079-6382}, support = {Taif University Researchers Supporting Project number (TURSP-2020/262), Taif University, PO Box 11099, Taif 21944, Saudi Arabia//Taif University/ ; }, abstract = {Backyard birds are small flocks that are more common in developing countries. They are used for poultry meat and egg production. However, they are also implicated in the maintenance and transmission of several zoonotic diseases, including multidrug-resistant bacteria. Enterococci are one of the most common zoonotic bacteria. They colonize numerous body sites and cause a wide range of serious nosocomial infections in humans. Therefore, the objective of the present study was to investigate the diversity in Enterococcus spp. in healthy birds and to determine the occurrence of multidrug resistance (MDR), multi-locus sequence types, and virulence genes and biofilm formation. From March 2019 to December 2020, cloacal swabs were collected from 15 healthy backyard broiler flocks. A total of 90 enterococci strains were recovered and classified according to the 16S rRNA sequence into Enterococcus faecalis (50%); Enterococcus faecium (33.33%), Enterococcus hirae (13.33%), and Enterococcus avium (3.33%). The isolates exhibited high resistance to tetracycline (55.6%), erythromycin (31.1%), and ampicillin (30%). However, all of the isolates were susceptible to linezolid. Multidrug resistance (MDR) was identified in 30 (33.3%) isolates. The enterococci AMR-associated genes ermB, ermA, tetM, tetL, vanA, cat, and pbp5 were identified in 24 (26.6%), 11 (12.2%), 39 (43.3%), 34 (37.7%), 1 (1.1%), 4 (4.4%), and 23 (25.5%) isolates, respectively. Of the 90 enterococci, 21 (23.3%), 27 (30%), and 36 (40%) isolates showed the presence of cylA, gelE, and agg virulence-associated genes, respectively. Seventy-three (81.1%) isolates exhibited biofilm formation. A statistically significant correlation was obtained for biofilm formation versus the MAR index and MDR. Multi-locus sequence typing (MLST) identified eleven and eight different STs for E. faecalis and E. faecium, respectively. Seven different rep-family plasmid genes (rep1-2, rep3, rep5-6, rep9, and rep11) were detected in the MDR enterococci. Two-thirds (20/30; 66.6%) of the enterococci were positive for one or two rep-families. In conclusion, the results show that healthy backyard chickens could act as a reservoir for MDR and virulent Enterococcus spp. Thus, an effective antimicrobial stewardship program and further studies using a One Health approach are required to investigate the role of backyard chickens as vectors for AMR transmission to humans.}, } @article {pmid35325969, year = {2022}, author = {Liu, J and Wu, BL and Zhu, WZ and Liu, J and Wang, T and Geng, MM and Bai, L and Liu, Y}, title = {[Effect of hypochloric acid on Escherichia coli biofilm and the clinical efficacy of hypochloric acid for wounds with Escherichia coli infection].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {38}, number = {3}, pages = {242-250}, doi = {10.3760/cma.j.cn501120-20201112-00471}, pmid = {35325969}, issn = {1009-2587}, mesh = {Adult ; Aged ; Biofilms ; *Escherichia coli ; *Escherichia coli Infections/drug therapy ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Surgical Wound Infection ; Treatment Outcome ; }, abstract = {Objective: To investigate the effect of hypochloric acid on Escherichia coli biofilm and the clinical efficacy of hypochloric acid for wounds with Escherichia coli infection. Methods: One strain of Escherichia coli with the strongest bacterial biofilm forming ability among the strains isolated from specimens in 25 patients (16 males and 9 females, aged 32-67 years) from five clinical departments of the 940[th] Hospital of the Joint Logistic Support Force was collected for the experimental study from September to December 2019. The Escherichia coli was cultured with hypochloric acid at 162.96, 81.48, 40.74, 20.37, 10.18, 5.09, 2.55, 1.27, 0.64, and 0.32 μg/mL respectively to screen the minimum bactericidal concentration (MBC) of hypochloric acid. The Escherichia coli was cultured with hypochloric acid at the screened MBC for 2, 5, 10, 20, 30, and 60 min respectively to screen the shortest bactericidal time of hypochloric acid. The biofilm formation of Escherichia coli was observed by scanning electron microscopy at 6, 12, 24, 48, 72, and 96 h of incubation, respectively. After 72 h of culture, hypochloric acid at 1, 2, 4, 8, and 16 times of MBC was respectively added to Escherichia coli to screen the minimum biofilm eradicate concentration (MBEC) of hypochloric acid against Escherichia coli. After hypochloric acid at 1, 2, 4, and 8 times of MBEC and sterile saline were respectively added to Escherichia coli for 10 min, the live/dead bacterial staining kit was used to detect the number of live and dead cells, with the rate of dead bacteria calculated (the number of samples was 5). From January to December 2020, 41 patients with infectious wounds meeting the inclusion criteria and admitted to the Department of Burns and Plastic Surgery of the 940[th] Hospital of Joint Logistic Support Force of PLA were included into the prospective randomized controlled trial. The patients were divided into hypochloric acid group with 21 patients (13 males and 8 females, aged (46±14) years) and povidone iodine group with 20 patients (14 males and 6 females, aged (45±19) years) according to the random number table. Patients in the 2 groups were respectively dressed with sterile gauze soaked with hypochloric acid of 100 μg/mL and povidone iodine solution of 50 mg/mL with the dressings changed daily. Before the first dressing change and on the 10[th] day of dressing change, tissue was taken from the wound and margin of the wound for culturing bacteria by agar culture method and quantifying the number of bacteria. The amount of wound exudate and granulation tissue growth were observed visually and scored before the first dressing change and on the 3[rd], 7[th], and 10[th] days of dressing change. Data were statistically analyzed with one-way analysis of variance, Dunnett-t test, independent sample t test, Mann-Whitney U test, Wilcoxon signed-rank test, chi-square test, or Fisher's exact probability test. Results: The MBC of hypochloric acid against Escherichia coli was 10.18 μg/mL, and the shortest bactericidal time of hypochloric acid with MBC against Escherichia coli was 2 min. Escherichia coli was in a completely free state after 6 and 12 h of culture and gradually aggregated and adhered with the extension of culture time, forming a mature biofilm at 72 h of culture. The MBEC of hypochloric acid against Escherichia coli was 20.36 μg/mL. The Escherichia coli mortality rates after incubation with hypochloric acid at 1, 2, 4, and 8 times of MBEC for 10 min were significantly higher than that after incubation with sterile saline (with t values of 6.11, 25.04, 28.90, and 40.74, respectively, P<0.01). The amount of bacteria in the wound tissue of patients in hypochloric acid group on the 10[th] day of dressing change was 2.61 (2.20, 3.30)×10[4] colony forming unit (CFU)/g, significantly less than 4.77 (2.18, 12.48)×10[4] CFU/g in povidone iodine group (Z=2.06, P<0.05). The amounts of bacteria in the wound tissue of patients in hypochloric acid group and povidone iodine group on the 10[th] day of dressing change were significantly less than 2.97 (2.90, 3.04)×10[6] and 2.97 (1.90, 7.95)×10[6] CFU/g before the first dressing change (with Z values of 4.02 and 3.92, respectively, P<0.01). The score of wound exudate amount of patients in hypochloric acid group on the 10[th] day of dressing change was significantly lower than that in povidone iodine group (Z=2.07, P<0.05). Compared with those before the first dressing change, the scores of wound exudate amount of patients in hypochloric acid group on the 7[th] and 10[th] days of dressing change were significantly decreased (with Z values of -3.99 and -4.12, respectively, P<0.01), and the scores of wound exudate amount of patients in povidone iodine group on the 7[th] and 10[th] days of dressing change were significantly decreased (with Z values of -3.54 and -3.93, respectively, P<0.01). The score of wound granulation tissue growth of patients in hypochloric acid group on the 10[th] day of dressing change was significantly higher than that in povidone iodine group (Z=2.02, P<0.05). Compared with those before the first dressing change, the scores of wound granulation tissue growth of patients in hypochloric acid group on the 7[th] and 10[th] days of dressing change were significantly increased (with Z values of -3.13 and -3.67, respectively, P<0.01), and the scores of wound granulation tissue growth of patients in povidone iodine group on the 7[th] and 10[th] days of dressing change were significantly increased (with Z values of -3.12 and -3.50, respectively, P<0.01). Conclusions: Hypochloric acid can kill Escherichia coli both in free and biofilm status. Hypochloric acid at a low concentration shows a rapid bactericidal effect on mature Escherichia coli biofilm, and the higher the concentration of hypochloric acid, the better the bactericidal effect. The hypochloric acid of 100 μg/mL is effective in reducing the bacterial load on wounds with Escherichia coli infection in patients, as evidenced by a reduction in wound exudate and indirect promotion of granulation tissue growth, which is more effective than povidone iodine, the traditional topical antimicrobial agent.}, } @article {pmid35325859, year = {2022}, author = {Zhu, J and Wang, J and Chen, YP and Qing, T and Zhang, P and Feng, B}, title = {Quantitative proteomics and phosphoproteomics elucidate the molecular mechanism of nanostructured TiO2-stimulated biofilm formation.}, journal = {Journal of hazardous materials}, volume = {432}, number = {}, pages = {128709}, doi = {10.1016/j.jhazmat.2022.128709}, pmid = {35325859}, issn = {1873-3336}, mesh = {Biofilms ; *Escherichia coli ; *Nanostructures ; Proteomics ; Titanium/pharmacology ; }, abstract = {With the increasing concerns regarding bacterial adaption to nanomaterials, it is critical to explore the main mechanism behind the adaptive morphogenesis of microorganisms. In this work, the biofilms formed from activated sludge exposed to 5 and 50 mg/L nTiO2 in the dark had increased biomass and selectively enriched pathogens. To further elaborate adaptive mechanism of biofilm formation induced by nTiO2, the protein response and protein phosphorylation modification of Escherichia coli K12 were determined using integrative systems biology analyses of proteomics and phosphoproteomics. Results identified that E. coli cultivated with nTiO2 considerably upregulated iron acquisition, and regulated protein phosphorylation states associated with of transcription and translation and biofilm formation relative to unexposed controls. Accordingly, bacteria increased siderophores and exopolysaccharide content (increased by about 57% and 231%, respectively), and enhanced resistance to transcriptional inhibitory antibiotics. Moreover, a dose of an iron chelator, i.e., deferoxamine mesylate salt, effectively retarded the biofilm development of bacteria exposed to 50 mg/L nTiO2. Overall, this work will provide a new insight for biofouling control, and contribute to an improved understanding of microbial adaption to nanomaterials.}, } @article {pmid35325574, year = {2022}, author = {Müller, AR and Leite, BR and Corção, G}, title = {Analysis of Antibiotic Resistance and Biofilm-Forming Capacity in Tetracycline-Resistant Bacteria from a Coastal Lagoon.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {28}, number = {6}, pages = {654-659}, doi = {10.1089/mdr.2021.0255}, pmid = {35325574}, issn = {1931-8448}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial ; *Enterococcus faecium/genetics ; Escherichia coli ; Microbial Sensitivity Tests ; Tetracycline/pharmacology ; }, abstract = {Concerns have been raised regarding co-selection for antibiotic resistance among bacteria exposed to antibiotics used as growth promoters for some livestock and poultry species. Tetracycline had been commonly used for this purpose worldwide, and its residue has been associated with selection of resistant bacteria in aquatic biofilms. This study aimed to determine the resistance profile, the existence of some beta-lactamases genes and the capacity to form biofilm of bacteria isolated from water samples previously exposed to tetracycline (20 mg/L). Thirty-seven tetracycline-resistant bacterial strains were identified as Serratia marcescens, Escherichia coli, Morganella morganii, Pseudomonas aeruginosa, Citrobacter freundii, Providencia alcalifaciens, and Enterococcus faecium. The highest percentage of resistance was for ampicillin (75.75%) and amoxicillin/clavulanic acid (66.66%) in the Gram-negative bacteria and an E. faecium strain showed high resistance to vancomycin (minimum inhibitory concentration 250 μg/mL). Among the strains analyzed, 81.09% had multidrug resistance and eight Gram-negatives carried the blaOXA-48 gene. All strains were able to form biofilm and 43.23% were strong biofilm formers. This study suggests that resistant bacteria can be selected under selection pressure of tetracycline, and that these bacteria could contribute to the maintenance and spread of antimicrobial resistance in this environment.}, } @article {pmid35325386, year = {2022}, author = {Wang, J and Li, X and Kong, R and Wu, J and Wang, X}, title = {Fractal morphology facilitates Bacillus subtilis biofilm growth.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {37}, pages = {56168-56177}, pmid = {35325386}, issn = {1614-7499}, support = {11972074//National Natural Science Foundation of China/ ; 11772047//National Natural Science Foundation of China/ ; 11620101001//National Natural Science Foundation of China/ ; }, mesh = {Adaptation, Physiological ; *Bacillus subtilis ; Bacterial Proteins ; Biofilms ; Environment ; *Fractals ; }, abstract = {In the late stage of Bacillus subtilis biofilm growth, to adapt the extremely nutrient-lacking environment, the biofilm edge grows into a complex branching structure, which allows the biofilm to expand outward at a faster speed, comparing to the expansion speed of the biofilm edge without branching structure. The fractal analysis shows that the fractal dimension (Fd) decreases along the radius in the biofilm branching structure, as shown in Figs. 1d and 3a. The variation of Fd along the radius is not monotonic, which is because of the texture evolution induced by the bacterial clusters' movement. By using the wide field stereomicroscope and image analysis, we find that the ridges in the mature branching structure are composed of inactive substances, and most of the bacterial clusters move through the valleys. Further analysis shows that bacterial clusters move to the area with the high Succolarity (Suc) value.}, } @article {pmid35325333, year = {2022}, author = {Li, J and Zhang, Q and Zhao, J and Zhang, H and Chen, W}, title = {Streptococcus mutans and Candida albicans Biofilm Inhibitors Produced by Lactiplantibacillus plantarum CCFM8724.}, journal = {Current microbiology}, volume = {79}, number = {5}, pages = {143}, pmid = {35325333}, issn = {1432-0991}, support = {32072197//National Natural Science Foundation of China/ ; 32021005//National Natural Science Foundation of China/ ; }, mesh = {Biofilms ; Candida albicans ; *Probiotics ; *Streptococcus mutans ; }, abstract = {Lactiplantibacillus plantarum CCFM8724 inhibits the growth of Streptococcus mutans and Candida albicans in mixed-species biofilm formation. In this study, bioactive compound including cyclo (leu-pro), cyclo (phe-pro), and some organic acids, such as 3-phenyllactic acid, hydrocinnamic acid, and palmitic acid, were identified through GC-MS analysis. At 50 μg·mL[-1], cyclo (leu-pro) reduced biofilm mass (OD600) from 3.00 to 2.00, and hydrocinnamic acid at 25 μg·mL[-1] reduced biofilm mass (OD600) from 3.00 to 1.00. The expression of ALS3 and HWP1 was downregulated by cyclo (leu-pro). Furthermore, a mixture of cyclo (leu-pro), cyclo (phe-pro), 3-phenyllactic acid, hydrocinnamic acid, and palmitic acid, had anti-biofilm activity. Overall, the results provide promising baseline information for the potential use of this probiotic and its components in preventing biofilm formation.}, } @article {pmid35325273, year = {2022}, author = {Bourguignon, N and Kamat, V and Perez, M and Mathee, K and Lerner, B and Bhansali, S}, title = {New dynamic microreactor system to mimic biofilm formation and test anti-biofilm activity of nanoparticles.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {7}, pages = {2729-2738}, pmid = {35325273}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; *Chitosan/chemistry/pharmacology ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Silver/pharmacology ; }, abstract = {Microbial biofilms are composed of surface-adhered microorganisms enclosed in extracellular polymeric substances. The biofilm lifestyle is the intrinsic drug resistance imparted to bacterial cells protected by the matrix. So far, conventional drug susceptibility tests for biofilm are reagent and time-consuming, and most of them are in static conditions. Rapid and easy-to-use methods for biofilm formation and antibiotic activity testing need to be developed to accelerate the discovery of new antibiofilm strategies. Herein, a Lab-On-Chip (LOC) device is presented that provides optimal microenvironmental conditions closely mimicking real-life clinical biofilm status. This new device allows homogeneous attachment and immobilization of Pseudomonas aeruginosa PA01-EGFP cells, and the biofilms grown can be monitored by fluorescence microscopy. P. aeruginosa is an opportunistic pathogen known as a model for drug screening biofilm studies. The influence of flow rates on biofilms growth was analyzed by flow simulations using COMSOL® 5.2. Significant cell adhesion to the substrate and biofilm formation inside the microchannels were observed at higher flow rates > 100 µL/h. After biofilm formation, the effectiveness of silver nanoparticles (SNP), chitosan nanoparticles (CNP), and a complex of chitosan-coated silver nanoparticles (CSNP) to eradicate the biofilm under a continuous flow was explored. The most significant loss of biofilm was seen with CSNP with a 65.5% decrease in average live/dead cell signal in biofilm compared to the negative controls. Our results demonstrate that this system is a user-friendly tool for antibiofilm drug screening that could be simply applied in clinical laboratories.Key Points• A continuous-flow microreactor that mimics real-life clinical biofilm infections was developed.• The antibiofilm activity of three nano drugs was evaluated in dynamic conditions.• The highest biofilm reduction was observed with chitosan-silver nanoparticles.}, } @article {pmid35325152, year = {2022}, author = {Pormohammad, A and Greening, D and Turner, RJ}, title = {Synergism inhibition and eradication activity of silver nitrate/potassium tellurite combination against Pseudomonas aeruginosa biofilm.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {6}, pages = {1635-1644}, doi = {10.1093/jac/dkac094}, pmid = {35325152}, issn = {1460-2091}, support = {//NSERC/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections/drug therapy ; *Pseudomonas aeruginosa ; Silver Nitrate/pharmacology ; Tellurium ; }, abstract = {OBJECTIVES: Antibiotic resistance, biofilm and persistent infection of Pseudomonas aeruginosa is a perilous challenge in the healthcare system. Hence, a vast number of novel antipseudomonas approaches are currently being pursued. Our group focuses on exploring the efficacy of metal(loid)-based antimicrobials (MBAs) towards novel infection control solutions.

METHODS: Initially, nine MBAs were tested for biofilm prevention and eradication efficacy. Synergistic potentials were then screened systematically in a total of 1920 combinatorial MBA concentrations, in laboratory media [CAMHB and LB] and infection-related simulated wound fluid (SWF). The antibiofilm efficacy of the silver nitrate (AgNO3; 'Ag') with potassium tellurite (K2TeO3; 'Te') combination was examined against clinical antibiotic-resistant isolates and compared with the most used antibiotics. The in vitro resistance acquisition test, for exploring the chance of getting future resistance, and meta-analysis, for estimating Ag/Te human cell cytotoxicity, were carried out.

RESULTS: The Ag/Te combination was identified as the most effective agent against P. aeruginosa biofilm. The application of the Ag/Te combination was quite effective against all clinical isolates. Comparison of clinical isolates with indicator strains showed clinical isolates are gaining resistance against the antibiotics (especially gentamicin) and Ag, while they are susceptible to Te and particularly the Ag/Te combination. The chance of getting future resistance against Ag/Te as a mixture was remarkably lower than the individual application of each metal. Te has significantly lower human cell cytotoxicity in comparison with Ag.

CONCLUSIONS: Te could be an appropriate alternative against P. aeruginosa biofilms (existing or prevention thereof), especially in combination with Ag.}, } @article {pmid35324837, year = {2022}, author = {Ahmed, HA and El Bayomi, RM and Hamed, RI and Mohsen, RA and El-Gohary, FA and Hefny, AA and Elkhawaga, E and Tolba, HMN}, title = {Genetic Relatedness, Antibiotic Resistance, and Effect of Silver Nanoparticle on Biofilm Formation by Clostridium perfringens Isolated from Chickens, Pigeons, Camels, and Human Consumers.}, journal = {Veterinary sciences}, volume = {9}, number = {3}, pages = {}, pmid = {35324837}, issn = {2306-7381}, abstract = {In this study, we determined the prevalence and toxin types of antibiotic-resistant Clostridium perfringens in chicken, pigeons, camels, and humans. We investigated the inhibitory effects of AgNPs on biofilm formation ability of the isolates and the genetic relatedness of the isolates from various sources determined using RAPD-PCR. Fifty isolates were identified using PCR, and all the isolates were of type A. The cpe and cpb2 genes were detected in 12% and 56% of the isolates, respectively. The effect of AgNPs on biofilm production of six representative isolates indicated that at the highest concentration of AgNPs (100 µg/mL), the inhibition percentages were 80.8-82.8%. The RAPD-PCR patterns of the 50 C. perfringens isolates from various sources revealed 33 profiles and four clusters, and the discriminatory power of RAPD-PCR was high. Multidrug-resistant C. perfringens isolates are predominant in the study area. The inhibition of biofilm formation by C. perfringens isolates was dose-dependent, and RAPD-PCR is a promising method for studying the genetic relatedness between the isolates from various sources. This is the first report of AgNPs' anti-biofilm activity against C. perfringens from chickens, pigeons, camels, and humans, to the best of our knowledge.}, } @article {pmid35324063, year = {2022}, author = {Discepoli, N and Mirra, R and Vesentin, C and Marruganti, C and Ferrari, M}, title = {Artificial biofilm removal in a peri-implant mucositis model: Efficacy of air polishing technology as adjunct to ultrasonic debridement alone and impact of the site and the depth of mucosal tunnel-An in vitro study.}, journal = {Clinical implant dentistry and related research}, volume = {24}, number = {2}, pages = {242-250}, doi = {10.1111/cid.13077}, pmid = {35324063}, issn = {1708-8208}, mesh = {Biofilms ; Debridement ; *Dental Implants ; Dental Polishing ; Glycine ; Humans ; *Mucositis ; *Peri-Implantitis/therapy ; Powders ; Technology ; Ultrasonics ; }, abstract = {AIM: The current in vitro model aims to evaluate the adjunctive effect on artificial biofilm removal determined by the use of a glycine-powder air-polishing procedure (GPAP) over the ultrasonic debridement (USD) alone when the removal of artificial biofilm on abutment surface is performed. The procedures were carried out also evaluating the impact of the site (mesial, distal, vestibular, and oral) and three different mucosal tunnel depths (2 mm, 4 mm, and 6 mm).

MATERIALS AND METHODS: Single tooth implant replacement was simulated. Three different abutment heights together with a prosthetic contour were investigated (2 mm, 4 mm, and 6 mm); custom-made gingival masks were created to mimic peri-implant soft tissue. Biofilm was simulated with an indelible ink. The protocol consisted in two intervention stages for each abutment: (a) USD with PEEK tip plus (b) GPAP. At the end of each intervention, abutments were unscrewed, and standardized photographs were taken. Statistical analysis was carried out to compare residual stain percentage between the two intervention stages and among different sites and mucosal tunnels.

RESULTS: A total of 30 abutments were instrumented. A significant reduction of the percentage of residual staining (PRS) after the combination of GPAP + USD over USD alone was demonstrated (16% vs. 32%; p < 0.05). Moreover, the better performance of the GPAP + USD protocol was observed regardless of the different mucosal tunnel heights and the sites analyzed. Intragroup analysis unveils that the smaller PRS was observed for shallow mucosal tunnels (2 mm) and vestibular sites for both protocols.

CONCLUSION: GPAP + USD provided adjunctive effect on artificial biofilm removal in comparison to the USD alone. Furthermore, proximal surfaces and deeper mucosal tunnels (4 and 6 mm) showed a reduced instrumentation efficacy for both protocols.}, } @article {pmid35323810, year = {2022}, author = {Javier, L and Pulido-Beltran, L and Vrouwenvelder, JS and Farhat, NM}, title = {Permeation Increases Biofilm Development in Nanofiltration Membranes Operated with Varying Feed Water Phosphorous Concentrations.}, journal = {Membranes}, volume = {12}, number = {3}, pages = {}, pmid = {35323810}, issn = {2077-0375}, support = {BAS/1/1024-01-01//King Abdullah University of Science and Technology/ ; }, abstract = {Nutrient limitation has been proposed as a biofouling control strategy for membrane systems. However, the impact of permeation on biofilm development under phosphorus-limited and enriched conditions is poorly understood. This study analyzed biofilm development in membrane fouling simulators (MFSs) with and without permeation supplied with water varying dosed phosphorus concentrations (0 and 25 μg P·L[-1]). The MFSs operated under permeation conditions were run at a constant flux of 15.6 L·m[2]·h[-1] for 4.7 days. Feed channel pressure drop, transmembrane pressure, and flux were used as performance indicators. Optical coherence tomography (OCT) images and biomass quantification were used to analyze the developed biofilms. The total phosphorus concentration that accumulated on the membrane and spacer was quantified by using microwave digestion and inductively coupled plasma atomic emission spectroscopy (ICP-OES). Results show that permeation impacts biofilm development depending on nutrient condition with a stronger impact at low P concentration (pressure drop increase: 282%; flux decline: 11%) compared to a higher P condition (pressure drop increase: 206%; flux decline: 2%). The biofilm that developed at 0 μg P·L[-1] under permeation conditions resulted in a higher performance decline due to biofilm localization and spread in the MFS. A thicker biofilm developed on the membrane for biofilms grown at 0 μg P·L[-1] under permeation conditions, causing a stronger effect on flux decline (11%) compared to non-permeation conditions (5%). The difference in the biofilm thickness on the membrane was attributed to a higher phosphorus concentration in the membrane biofilm under permeation conditions. Permeation has an impact on biofilm development and, therefore, should not be excluded in biofouling studies.}, } @article {pmid35323235, year = {2022}, author = {Marashdeh, MQ and Lévesque, C and Friedman, S and Stewart, CA and Finer, Y}, title = {Interfacial Biomaterial-Dentin Bacterial Biofilm Proliferation and Viability Is Affected by the Material, Aging Media and Period.}, journal = {Dentistry journal}, volume = {10}, number = {3}, pages = {}, pmid = {35323235}, issn = {2304-6767}, support = {R01DE021385-0/NH/NIH HHS/United States ; MOP 115113/CAPMC/CIHR/Canada ; PJT-165957/CAPMC/CIHR/Canada ; John R. Evans Leaders Fund (CFI_JELF) [project #35378]//Canada Foundation for Innovation/ ; Ontario Research fund (ORF) [ORF-35378]//Ministry of Research and Innovation (MRI)/ ; Connaught Innovation Award//University of Toronto/ ; }, abstract = {Biomaterial−dentin interfaces undergo degradation over time, allowing salivary, tissue fluid, and bacterial movement between the root filling or restoration and dentin. This study aims to investigate the effect of aging in simulated human salivary/bacterial/blood esterases (SHSE) on proliferation and viability of Enterococcus faecalis biofilm within the dentin interface with four materials used to fill/restore the endodontic space. Root canals of human anterior teeth were prepared and filled with gutta-percha and one of the following: self-cured resin composite (BisfilTM 2B, Bisco, Schaumburg, IL, USA) with either self-etch (SE) (EasyBond) or total-etch (TE) (ScotchbondTM, 3M, Saint Paul, MN, USA) methacrylate-based adhesives, epoxy-resin sealer (AH Plus®, Dentsply Sirona, York, PA, USA), or bioceramic sealer (EndoSequence® BC Sealer™, Brasseler USA, Savannah, GA, USA). Specimens were aged in SHSE or phosphate-buffered saline (PBS) for up to 360 days, followed by cultivation of steady-state E. faecalis biofilm. Depth and viability of interfacial bacterial biofilm proliferation were assessed by confocal laser scanning microscopy and live/dead staining. Data were analyzed using three-way ANOVA and Scheffe’s post hoc analyses. Initial depths of biofilm proliferation were similar among material groups (p > 0.05). All groups showed significantly deeper biofilm proliferation with increased aging period (p < 0.05). SHSE aging increased interfacial biofilm depth for TE, SE and BC (p < 0.05) but not AH. For unaged interfaces, BC exhibited the lowest ratio of live bacteria, followed by AH, TE, and SE (p < 0.05). Interfacial bacterial biofilm proliferation and viability were dependent on the biomaterial, aging media, and period.}, } @article {pmid35323023, year = {2022}, author = {Wang, Z and Xie, X and Shang, D and Xie, L and Hua, Y and Song, L and Yang, Y and Wang, Y and Shen, X and Zhang, L}, title = {A c-di-GMP Signaling Cascade Controls Motility, Biofilm Formation, and Virulence in Burkholderia thailandensis.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {7}, pages = {e0252921}, pmid = {35323023}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Burkholderia ; Cyclic GMP/analogs & derivatives/metabolism ; *Escherichia coli Proteins/genetics ; *Gene Expression Regulation, Bacterial ; Phosphoric Diester Hydrolases/metabolism ; Phosphorus-Oxygen Lyases/genetics/metabolism ; Virulence ; }, abstract = {As a key bacterial second messenger, cyclic di-GMP (c-di-GMP) regulates various physiological processes, such as motility, biofilm formation, and virulence. Cellular c-di-GMP levels are regulated by the opposing activities of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs). Beyond that, the enzymatic activities of c-di-GMP metabolizing proteins are controlled by a variety of extracellular signals and intracellular physiological conditions. Here, we report that pdcA (BTH_II2363), pdcB (BTH_II2364), and pdcC (BTH_II2365) are cotranscribed in the same operon and are involved in a regulatory cascade controlling the cellular level of c-di-GMP in Burkholderia thailandensis. The GGDEF domain-containing protein PdcA was found to be a DGC that modulates biofilm formation, motility, and virulence in B. thailandensis. Moreover, the DGC activity of PdcA was inhibited by phosphorylated PdcC, a single-domain response regulator composed of only the phosphoryl-accepting REC domain. The phosphatase PdcB affects the function of PdcA by dephosphorylating PdcC. The observation that homologous operons of pdcABC are widespread among betaproteobacteria and gammaproteobacteria suggests a general mechanism by which the intracellular concentration of c-di-GMP is modulated to coordinate bacterial behavior and virulence. IMPORTANCE The transition from planktonic cells to biofilm cells is a successful strategy adopted by bacteria to survive in diverse environments, while the second messenger c-di-GMP plays an important role in this process. Cellular c-di-GMP levels are mainly controlled by modulating the activity of c-di-GMP-metabolizing proteins via the sensory domains adjacent to their enzymatic domains. However, in most cases how c-di-GMP-metabolizing enzymes are modulated by their sensory domains remains unclear. Here, we reveal a new c-di-GMP signaling cascade that regulates motility, biofilm formation, and virulence in B. thailandensis. While pdcA, pdcB, and pdcC constitute an operon, the phosphorylated PdcC binds the PAS sensory domain of PdcA to inhibit its DGC activity, with PdcB dephosphorylating PdcC to derepress the activity of PdcA. We also show this c-di-GMP regulatory model is widespread in the phylum Proteobacteria. Our study expands the current knowledge of how bacteria regulate intracellular c-di-GMP levels.}, } @article {pmid35321964, year = {2022}, author = {Kaypetch, R and Rudrakanjana, P and Churnjitapirom, P and Tua-Ngam, P and Tonput, P and Tantivitayakul, P}, title = {Geraniol and thymoquinone inhibit Candida spp. biofilm formation on acrylic denture resin without affecting surface roughness or color.}, journal = {Journal of oral science}, volume = {64}, number = {2}, pages = {161-166}, doi = {10.2334/josnusd.21-0435}, pmid = {35321964}, issn = {1880-4926}, mesh = {*Acrylic Resins/pharmacology ; Acyclic Monoterpenes ; Antifungal Agents/pharmacology ; Benzoquinones ; Biofilms ; *Candida ; Dentures/microbiology ; }, abstract = {PURPOSE: This study was designed to investigate the in vitro effects of geraniol (GE) and thymoquinone (TQ) on Candida biofilms on denture acrylic and any accompanying changes in acrylic surface roughness or color.

METHODS: The susceptibility of Candida species to GE and TQ was determined using the broth microdilution method and time-kill assay. A minimum biofilm eradication concentration (MBEC) assay was performed using 7-day Candida biofilms grown on denture acrylic.

RESULTS: The minimum inhibitory concentration (MIC) of GE and TQ for Candida spp. was 256 and 32 µg/mL, respectively. The Candida strain complete kill rates for GE and TQ at 5-fold MIC were determined after 1 h of incubation. At 5-fold MIC, GE and TQ inhibited the preformed biofilm activity (MBEC80) of all Candida strains on denture acrylic by more than 80% after treatment for 3 h. At sub-MIC levels, GE and TQ prevented the development of C. albicans and C. tropicalis hyphae. SEM images demonstrated that GE and TQ damaged the fungal cell membrane and induced cell lysis. On the other hand, GE and TQ at 10-fold MIC did not alter the surface roughness or color of the denture acrylic.

CONCLUSION: GE and TQ are interesting natural substances that could be developed as promising disinfectants for removable dentures.}, } @article {pmid35320632, year = {2022}, author = {Chervinets, VM and Chervinets, YV and Chichanovskaja, LV and Ganzja, DV and Grigoryants, EO and Belyaev, VS and Mironov, AY}, title = {The microbiome of oral cavity patients with periodontitis, adhesive and biofilm forming properties.}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {67}, number = {3}, pages = {163-169}, doi = {10.51620/0869-2084-2022-67-3-163-169}, pmid = {35320632}, issn = {0869-2084}, mesh = {Adhesives ; Biofilms ; Humans ; *Microbiota ; *Periodontitis ; }, abstract = {The work characterizes the intestinal microbiota of patients with ischemic stroke, including the spectrum, frequency and number of microorganisms, as well as the spectrum and amount of gas signaling molecules secreted by lactobacilli. It was found that in patients with ischemic stroke, the frequency of the main representatives of normal microflora, Bifidobacterium spp., Lactobacillus spp., Escherichia coli, decreased in 2-3 times, and the same time the prevalence of Clostridia spp., Bacillus spp., Peptostreptococcus spp., Klebsiella spp. increased in 2-3 times; yeast like fungi C. albicans was isolated in 25% of cases. Lactobacilli isolated from the intestinal microbiota of patients with ischemic stroke were represented by a wide variety of species: L. rhamnosus, L. fermentum, L. plantarum, L. brevis, L. pentosus, L. curvatus, L. salivarius. In most cases, they did not produce NO, they released CO 2 times less compared to healthy people. The most active NO producers - L. plantarum, CO - L. rhamnosus.}, } @article {pmid35318418, year = {2022}, author = {Nagahashi, T and Yahata, Y and Handa, K and Nakano, M and Suzuki, S and Kakiuchi, Y and Tanaka, T and Kanehira, M and Suresh Venkataiah, V and Saito, M}, title = {Er:YAG laser-induced cavitation can activate irrigation for the removal of intraradicular biofilm.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {4897}, pmid = {35318418}, issn = {2045-2322}, mesh = {Animals ; Biofilms ; *Lasers, Solid-State/therapeutic use ; Root Canal Irrigants ; Root Canal Preparation ; Root Canal Therapy ; Sodium Hypochlorite/pharmacology ; Swine ; *Tooth ; }, abstract = {We investigated the biofilm removal effects of laser activated irrigation (LAI) using a pig model, focusing on the impact of the fiber tip position, and used a high-speed camera to observe the occurrence and positioning of the cavitation associated with laser irradiation. A total of 16 roots of deciduous mandibular second premolars from 4 pigs were used. After a pulpectomy, the canals were left open for 2 weeks and sealed for 4 weeks to induce intraradicular biofilm. Root canal irrigation was then performed with Er:YAG laser activation. The fiber tip was inserted at two different positions, i.e., into the root canal in the intracanal LAI group and into the pulp chamber in the coronal LAI group. Intracanal needle irrigation with saline or 5% NaOCl was utilized in the positive control and conventional needle irrigation (CNI) groups. SEM and qPCR were carried out to evaluate treatment efficacy. Statistical analysis was performed using ANOVA and a Tukey-Kramer post-hoc test for qPCR and with a Steel-Dwass test to compare the SEM scores, with α = 0.05. A high-speed camera was used to observe the generation of cavitation bubbles and the movement of the induced bubbles after laser irradiation. The intracanal and coronal LAI groups showed significantly lower amounts of bacteria than either the positive control or CNI groups. There was no significant difference found between the intracanal and coronal LAI groups. SEM images revealed opened dentinal tubules with the destruction of biofilm in both LAI groups. High-speed camera images demonstrated cavitation bubble production inside the root canal after a single pulse irradiation pulse. The generated bubbles moved throughout the entire internal multi-rooted tooth space. Coronal LAI can generate cavitation in the root canal with a simply placed fiber inside the pulp chamber, leading to effective biofilm removal. This method could thus contribute to the future development of endodontic treatments for refractory apical periodontitis caused by intraradicular biofilm.}, } @article {pmid35318416, year = {2022}, author = {Wang, J and Zhang, Z and Li, J and Huang, B and Jiang, Z and Pan, Y and He, T and Hu, Y and Wang, L}, title = {Tranexamic acid protects against implant-associated infection by reducing biofilm formation.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {4840}, pmid = {35318416}, issn = {2045-2322}, mesh = {Animals ; *Antifibrinolytic Agents/pharmacology ; Biofilms ; Blood Loss, Surgical ; Humans ; Mice ; Postoperative Complications ; Postoperative Period ; *Tranexamic Acid/pharmacology ; }, abstract = {Perioperative administration of tranexamic acid (TXA) is thought to be related to decreased postoperative implant-associated infection rates; however, the relationship remains unclear. We explored the inhibitory effect of TXA on infection both in vitro and in vivo. We investigated biofilm formation after TXA administration through different detection methods, all of which showed that TXA reduces biofilm formation in vitro and was further proven to be associated with decreased protein and polysaccharide contents in biofilms. We observed decreased biofilm on implants and decreased bacteria in the infection area with strengthened neutrophil accumulation in the mouse implant-associated infection model. Our results suggest that TXA protects against implant-associated infection by reducing biofilm formation in infected tissues.}, } @article {pmid35315431, year = {2022}, author = {Liu, C and Sun, D and Liu, J and Chen, Y and Zhou, X and Ru, Y and Zhu, J and Liu, W}, title = {cAMP and c-di-GMP synergistically support biofilm maintenance through the direct interaction of their effectors.}, journal = {Nature communications}, volume = {13}, number = {1}, pages = {1493}, pmid = {35315431}, issn = {2041-1723}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic AMP Receptor Protein/genetics ; Cyclic GMP/analogs & derivatives/metabolism ; *Gene Expression Regulation, Bacterial ; *Signal Transduction/genetics ; }, abstract = {Nucleotide second messengers, such as cAMP and c-di-GMP, regulate many physiological processes in bacteria, including biofilm formation. There is evidence of cross-talk between pathways mediated by c-di-GMP and those mediated by the cAMP receptor protein (CRP), but the mechanisms are often unclear. Here, we show that cAMP-CRP modulates biofilm maintenance in Shewanella putrefaciens not only via its known effects on gene transcription, but also through direct interaction with a putative c-di-GMP effector on the inner membrane, BpfD. Binding of cAMP-CRP to BpfD enhances the known interaction of BpfD with protease BpfG, which prevents proteolytic processing and release of a cell surface-associated adhesin, BpfA, thus contributing to biofilm maintenance. Our results provide evidence of cross-talk between cAMP and c-di-GMP pathways through direct interaction of their effectors, and indicate that cAMP-CRP can play regulatory roles at the post-translational level.}, } @article {pmid35314887, year = {2022}, author = {Gupta, L and Sen, P and Bhattacharya, AK and Vijayaraghavan, P}, title = {Isoeugenol affects expression pattern of conidial hydrophobin gene RodA and transcriptional regulators MedA and SomA responsible for adherence and biofilm formation in Aspergillus fumigatus.}, journal = {Archives of microbiology}, volume = {204}, number = {4}, pages = {214}, pmid = {35314887}, issn = {1432-072X}, support = {EMR/2016/005752//Science and Engineering Research Board/ ; }, mesh = {*Aspergillus fumigatus/genetics ; Biofilms ; Eugenol/analogs & derivatives ; *Fungal Proteins/genetics/metabolism ; Spores, Fungal/genetics/metabolism ; }, abstract = {Aspergillus fumigatus is one of the major pathogenic fungal species, causing life-threatening infections. Due to a limited spectrum of available antifungals, exploration of new drug targets as well as potential antifungal molecules has become pertinent. Rodlet layer plays an important role in adherence of fungal conidia to hydrophobic cell surfaces in host, which also leads to A. fumigatus biofilm formation, contributing factor to fungal pathogenicity. From decades, natural sources have been known for the development of new active molecules. The present study investigates effect of isoeugenol on genes responsible for hydrophobins (RodA), adhesion as well as biofilm formation (MedA and SomA) of A. fumigatus. Minimum inhibitory concentrations (MIC and IC50) of isoeugenol against A. fumigatus were determined using broth microdilution assay. The IC50 results showed reduced hydrophobicity and biofilm formation as well as eradication after treatment with the compound and electron micrograph data corroborated these findings. The qRT-PCR showed a significant downregulation of genes RodA, MedA, SomA and pksP involved in hydrophobicity and biofilm formation. SwissADME studies potentiated drug-like propensity for isoeugenol which formed four hydrogen bonds with low binding energy (- 4.54 kcal/mol) at the catalytic site of RodA protein studied via AutoDock4. Hence, the findings conclude that isoeugenol inhibits conidial hydrophobicity and biofilm formation of A. fumigatus and further investigations are warranted in this direction.}, } @article {pmid35314292, year = {2022}, author = {Retsas, A and Dijkstra, RJB and van der Sluis, L and Boutsioukis, C}, title = {The Effect of the Ultrasonic Irrigant Activation Protocol on the Removal of a Dual-species Biofilm from Artificial Lateral Canals.}, journal = {Journal of endodontics}, volume = {48}, number = {6}, pages = {775-780}, doi = {10.1016/j.joen.2022.03.005}, pmid = {35314292}, issn = {1878-3554}, mesh = {Biofilms ; *Dental Pulp Cavity ; *Root Canal Irrigants/pharmacology ; Root Canal Preparation/methods ; Sodium Hypochlorite/pharmacology ; Therapeutic Irrigation/methods ; Ultrasonics ; Water ; }, abstract = {INTRODUCTION: Lateral canals are particularly challenging to clean and disinfect. The aim of this study was to compare the removal efficacy of a dual-species biofilm from a lateral canal model by different ultrasonic irrigant activation protocols in vitro.

METHODS: Artificial root canal models with 270 simulated lateral canals were made of polydimethylsiloxane. A dual-species biofilm (Streptococcus oralis and Actinomyces naeslundi) was grown in vitro in the lateral canals using a constant depth film fermenter. Two percent NaOCl or demineralized water was delivered by a syringe and an open-ended needle for 30 seconds and subsequently activated by an ultrasonic file for a total activation time of 30, 60, or 90 seconds divided in 1 or 3 consecutive activation cycles. In the control groups, the irrigant was allowed to rest for 30, 60, or 90 seconds. The volume of the biofilm in the lateral canal was evaluated before and after the final irrigation protocol by optical coherence tomography. The results were analyzed by 3-way factorial analysis of variance (α = 0.05).

RESULTS: Irrigation with NaOCl rather than demineralized water resulted in more effective biofilm removal from the lateral canal (P < .001). Three cycles of intermittent ultrasonic activation were significantly more effective than no activation (P = .029). The total irrigant contact time did not affect biofilm removal (P = .403).

CONCLUSIONS: The type of the irrigant and the ultrasonic activation protocol affected biofilm removal from artificial lateral canals. None of the compared protocols was able to eradicate the biofilm.}, } @article {pmid35314116, year = {2022}, author = {Otsuka, Y and Sasaki, K and Suyotha, W and Furusawa, H and Miyazawa, K and Konno, H and Yano, S}, title = {Construction of a fusion protein consisting of α-1,3-glucan-binding domains and tetrameric red fluorescent protein, which is involved in the aggregation of α-1,3-glucan and inhibition of fungal biofilm formation.}, journal = {Journal of bioscience and bioengineering}, volume = {133}, number = {6}, pages = {524-532}, doi = {10.1016/j.jbiosc.2022.02.008}, pmid = {35314116}, issn = {1347-4421}, mesh = {Biofilms ; *Cell Wall/metabolism ; *Glucans/metabolism ; Luminescent Proteins ; }, abstract = {Agl-KA, an α-1,3-glucan-hydrolyzing enzyme from Bacillus circulans KA-304, has three α-1,3-glucan-binding domains DS1, CB6, and DS2 (DCD). While their individual binding activities toward insoluble α-1,3-glucan and fungal cell-wall are weak, the three domains in combination bind strongly to the α-1,3-glucan and the cell-wall. In this study, we constructed DCD-tetraRFP by fusing DCD with DsRed-Express2, a tetrameric red fluorescent protein. DCD-tetraRFP forms a tetramer in an aqueous solution and contains twelve substrate-binding domains in one complex. We also constructed DCD-monoGFP by fusing DCD with AcGFP1, a monomeric green fluorescent protein. The molecular weight of DCD-tetraRFP and DCD-monoGFP were compared. The results of gel filtration chromatography and dynamic light scattering indicated that DCD-tetraRFP was larger than DCD-monoGFP, suggesting that DCD-tetraRFP had a tetrameric structure. In addition, DCD-tetraRFP bound to insoluble α-1,3-glucan strongly, and the amount of DCD-tetraRFP binding to 0.01% α-1,3-glucan was about twice of DCD-monoGFP. The Kd values of DCD-tetraRFP (measurements per subunit) and DCD-monoGFP were 0.16 and 0.84 μM, respectively. Adding DCD-tetraRFP to a suspension of α-1,3-glucan caused glucan aggregation; however, adding DCD-monoGFP did not. These data suggested that DCD-tetraRFP had four DCDs sterically arranged in different directions so that DCD-tetraRFP cross-linked with the substrate, causing aggregation. Lastly, the aggregates of DCD-tetraRFP and α-1,3-glucan captured Aspergillus oryzae conidia and decreased their biofilm formation by 80% in a 24-well dish.}, } @article {pmid35313556, year = {2022}, author = {Alshanta, OA and Albashaireh, K and McKloud, E and Delaney, C and Kean, R and McLean, W and Ramage, G}, title = {Candida albicans and Enterococcus faecalis biofilm frenemies: When the relationship sours.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100072}, pmid = {35313556}, issn = {2590-2075}, abstract = {The opportunistic yeast Candida albicans and lactic acid bacteria Enterococcus faecalis are frequently co-isolated from various infection sites on the human body, suggesting a common interkingdom interaction. While some reports suggest an antagonism, the reason for their co-isolation therefore remains unclear. The purpose of this study was to undertake a detailed characterisation of this dual-species interaction. We used standard biofilm characterisation methodologies alongside an RNASeq analysis to assess the response of C. albicans to E. faecalis. We evaluated the relevance of pH to dual-species biofilm interactions and demonstrated that E. faecalis rapidly and significantly impacted C. albicans morphogenesis and biofilm formation, which was mirrored by levels of gene expression. These transcripts were enriched in amino acids biosynthesis and metabolism pathways in co-cultures, a finding that guided our investigation into pH related mechanism. We were able to demonstrate the direct role of E. faecalis induced low pH, which inhibited C. albicans hyphal morphogenesis and biofilm formation. The results suggest that the anti-candidal effect of E. faecalis is not based solely on a single mechanism, instead it may involve various mechanisms, which collectively reflects the complexity of interaction between C. albicans and E. faecalis and impacts treatment outcomes.}, } @article {pmid35312889, year = {2022}, author = {Hageskal, G and Heggeset, TMB and Nguyen, GS and Haugen, T and Jønsson, M and Egas, C and Hidalgo, A and Wentzel, A and Lewin, AS}, title = {Flow-based method for biofilm microbiota enrichment and exploration of metagenomes.}, journal = {AMB Express}, volume = {12}, number = {1}, pages = {36}, pmid = {35312889}, issn = {2191-0855}, support = {Grant Agreement No 685474//h2020 european research council/ ; }, abstract = {Most bacteria live in biofilms in their natural habitat rather than the planktonic cell stage that dominates during traditional laboratory cultivation and enrichment schemes. The present study describes the establishment of a flow-based enrichment method based on multispecies biofilm communities for directing biofilm functionality using an environmental inoculum. By controlling flow conditions and physio-chemical properties, the set-up aims to simulate natural conditions ex situ for biofilm formation. The functionality of the method was demonstrated by enrichment of biofilm microbiomes using consortia from a warm compost pile and industrial waste materials as growth substrate, and further exploring the metagenomes by biotechnological tools. The 16S rRNA gene sequencing results revealed a difference in consortium composition and especially in genus abundance, in flow experiments compared to traditional liquid-shake experiments after enrichment, indicating good biofilm development and increased abundance of biofilm-forming taxa. The shotgun sequence mining demonstrated that different enzymes classes can be targeted by enriching biofilms on different substrates such as oat husk, pine saw dust, and lignin. The flow-based biofilm method is effective in reducing bacterial consortia complexity and in selecting biofilm-forming bacteria, and it is possible to enrich the biofilm community in various directions based on the choice of sample material, environmental conditions, and nutritional preferences, targeting enzymes or enzyme classes of industrial interest.}, } @article {pmid35311557, year = {2022}, author = {Katharios-Lanwermeyer, S and O'Toole, GA}, title = {Biofilm Maintenance as an Active Process: Evidence that Biofilms Work Hard to Stay Put.}, journal = {Journal of bacteriology}, volume = {204}, number = {4}, pages = {e0058721}, pmid = {35311557}, issn = {1098-5530}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; R21 AI055424/AI/NIAID NIH HHS/United States ; R01 AI155424/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; *Cyclic GMP/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; *Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/metabolism ; }, abstract = {Biofilm formation represents a critical strategy whereby bacteria can tolerate otherwise damaging environmental stressors and antimicrobial insults. While the mechanisms bacteria use to establish a biofilm and disperse from these communities have been well-studied, we have only a limited understanding of the mechanisms required to maintain these multicellular communities. Indeed, until relatively recently, it was not clear that maintaining a mature biofilm could be considered an active, regulated process with dedicated machinery. Using Pseudomonas aeruginosa as a model system, we review evidence from recent studies that support the model that maintenance of these persistent, surface-attached communities is indeed an active process. Biofilm maintenance mechanisms include transcriptional regulation and second messenger signaling (including the production of extracellular polymeric substances). We also discuss energy-conserving pathways that play a key role in the maintenance of these communities. We hope to highlight the need for further investigation to uncover novel biofilm maintenance pathways and suggest the possibility that such pathways can serve as novel antibiofilm targets.}, } @article {pmid35310353, year = {2022}, author = {Kim, JY and Choi, W and Mangal, U and Seo, JY and Kang, TY and Lee, J and Kim, T and Cha, JY and Lee, KJ and Kim, KM and Kim, JM and Kim, D and Kwon, JS and Hong, J and Choi, SH}, title = {Multivalent network modifier upregulates bioactivity of multispecies biofilm-resistant polyalkenoate cement.}, journal = {Bioactive materials}, volume = {14}, number = {}, pages = {219-233}, pmid = {35310353}, issn = {2452-199X}, abstract = {Polyalkenoate cement (PAC) is a promising material for regenerative hard tissue therapy. The ionically rich glass component of PAC encourages bioactive interaction via. the release of essential ions. However, PAC bioactivity is restricted owing to (i) structurally inherent cationic network formers and (ii) surface bacterial biofilm formation. These two factors cause a deficiency in ion release, further complicated by secondary infections and premature therapeutic failure. Here, a multivalent zwitterionic network modifier (mZM) is presented for upregulation of ionic exchange and bioactivity enhancement. By introducing a non-zero charged mZM into PACs, an increase in the proportion of non-bridging oxygen occurs. The network modification promotes ion channel formation, causing a multiple-fold increase in ion release and surface deposition of hydroxy-carbonate apatite (ca. 74%). Experiments ex vivo and animal models also demonstrate the efficient remineralization ability of the mZM. Furthermore, divalent cationic interaction results in bacterial biofilm reduction (ca. 68%) while also influencing a shift in the biofilm species composition, which favors commensal growth. Therefore, PAC modification with mZM offers a promising solution for upregulation of bioactivity, even aiding in customization by targeting site-specific regenerative therapy in future applications.}, } @article {pmid35309977, year = {2022}, author = {Li, B and Cai, Q and Wang, Z and Qiao, S and Ou, Y and Ma, R and Luo, C and Meng, W}, title = {D-arginine Enhances the Effect of Alpha-Amylase on Disassembling Actinomyces viscosus Biofilm.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {10}, number = {}, pages = {864012}, pmid = {35309977}, issn = {2296-4185}, abstract = {Peri-implantitis is the leading cause of dental implant failure, initially raised by biofilm accumulation on the implant surface. During the development of biofilm, Actinomyces viscosus (A. viscosus) plays a pivotal role in initial attachment as well as the bacterial coaggregation of multispecies pathogens. Hence, eliminating the A. viscosus-associated biofilm is fundamental for the regeneration of the lost bone around implants. Whereas clinical evidence indicated that antimicrobials and debridement did not show significant effects on the decontamination of biofilm on the implant surface. In this study, alpha-amylase was investigated for its effects on disassembling A. viscosus biofilm. Then, in order to substantially disperse biofilm under biosafety concentration, D-arginine was employed to appraise its enhancing effects on alpha-amylase. In addition, molecular dynamics simulations and molecular docking were conducted to elucidate the mechanism of D-arginine enhancing alpha-amylase. 0.1-0.5% alpha-amylase showed significant effects on disassembling A. viscosus biofilm, with definite cytotoxicity toward MC3T3-E1 cells meanwhile. Intriguingly, 8 mM D-arginine drastically enhanced the eradication of A. viscosus biofilm biomass by 0.01% alpha-amylase with biosafety in 30 min. The exopolysaccharides of biofilm were also thoroughly hydrolyzed by 0.01% alpha-amylase with 8 mM D-arginine. The biofilm thickness and integrity were disrupted, and the exopolysaccharides among the extracellular matrix were elusive. Molecular dynamics simulations showed that with the hydrogen bonding of D-arginine to the catalytic triad and calcium-binding regions of alpha-amylase, the atom fluctuation of the structure was attenuated. The distances between catalytic triad were shortened, and the calcium-binding regions became more stable. Molecular docking scores revealed that D-arginine facilitated the maltotetraose binding process of alpha-amylase. In conclusion, these results demonstrate that D-arginine enhances the disassembly effects of alpha-amylase on A. viscosus biofilm through potentiating the catalytic triad and stabilizing the calcium-binding regions, thus providing a novel strategy for the decontamination of biofilm contaminated implant surface.}, } @article {pmid35309450, year = {2022}, author = {Nandy, P and Santra, RC and Lahiri, D and Nag, M and Das, S}, title = {In Situ Reactivity of Electrochemically Generated Nitro Radical Anion on Tinidazole and Its Monomeric and Dimeric Cu[II] Complexes on Model Biological Targets with Relative Manifestation of Preventing Bacterial Biofilm Formation.}, journal = {ACS omega}, volume = {7}, number = {10}, pages = {8268-8280}, pmid = {35309450}, issn = {2470-1343}, abstract = {Formation of nitro radical anion (-NO2 [•-]) and other reduction products of 5-nitroimidazoles, although important for antimicrobial activity, makes the drugs neurotoxic. Hence, an appropriate generation and their role in the free radical pathway needs proper realization. This was attempted by studying the action of tinidazole and its Cu[II] complexes on model targets (nucleic acid bases and calf thymus DNA). Results obtained were correlated with studies on biological species where prevention of biofilm formation on Staphylococcus aureus and Pseudomonas aeruginosa was followed. Tinidazole and its Cu[II] complexes subjected to electrochemical reduction in aqueous solution, under de-aerated conditions, interact with model nucleic acid bases and calf thymus DNA. These model targets were followed to realize what happens when such compounds undergo enzymatic reduction within cells of microorganisms that they eventually kill. Studies reveal that Cu[II] complexes were better in modifying nucleic acid bases and calf thymus DNA than tinidazole; damage caused to nucleic acid bases was correlated with that caused to DNA, indicating that compounds affect DNA rich in thymine and adenine. Minimum bactericidal concentrations on sessile S. aureus and P. aeruginosa for the monomeric Cu[II] complex were 12.5 and 20.25 μM respectively, while those for the dimeric complex were 40.0 and 45.0 μM, respectively. Biofilm formation by P. aeruginosa and S. aureus and viability count of sessile cells were also determined. Cu[II] complexes of tinidazole brought about substantial reduction in carbohydrate and protein content in S. aureus and P. aeruginosa. Downregulation of quorum sensing signaling mechanism viz. reduced production of pyocyanin and elastase during biofilm formation was also detected. Cu[II] complexes showed much higher tendency to prevent biofilm formation than tinidazole, almost comparable to amoxicillin, an established drug in this regard.}, } @article {pmid35309438, year = {2022}, author = {Liu, Y and Shi, Y and Cheng, H and Chen, J and Wang, Z and Meng, Q and Tang, Y and Yu, Z and Zheng, J and Shang, Y}, title = {Lapatinib Acts against Biofilm Formation and the Hemolytic Activity of Staphylococcus aureus.}, journal = {ACS omega}, volume = {7}, number = {10}, pages = {9004-9014}, pmid = {35309438}, issn = {2470-1343}, abstract = {Biofilm formation and hemolytic activity are closely related to the pathogenesis of Staphylococcus aureus infections. Herein, we show that lapatinib (12.5 μM) significantly inhibits biofilm formation and hemolytic activity of both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates. Using quantitative reverse transcription PCR, we found that the RNA levels of transcriptional regulatory genes (RNAIII, agrA, agrC, saeR, and saeS), biofilm-formation-related genes (atl, cidA, clfA, clfB, and icaA), and virulence-related genes (cap5A, hla, hld, hlg, lukDE, lukpvl-S, staphopain B, alpha-3 PSM, beta PSM, and delta PSM) of S. aureus decreased after 6 h treatment with lapatinib. Wild-type S. aureus isolates were continuously cultured in vitro in the presence of increasing concentrations of lapatinib for about 140 days. Subsequently, S. aureus isolates with reduced susceptibility to lapatinib (the inhibitory effect of lapatinib on the biofilm formation of these S. aureus isolates was significantly weakened) were selected. Mutations in the genomes of S. aureus isolates with reduced susceptibility to lapatinib were detected by whole-genome sequencing. We identified four genes with mutations: three genes with known functions (membrane protein, pyrrolidone-carboxylate peptidase, and sensor histidine kinase LytS, respectively) and one gene with unknown function (hypothetical protein). In conclusion, this study indicates that lapatinib significantly inhibits biofilm formation and the hemolytic activity of S. aureus.}, } @article {pmid35309435, year = {2022}, author = {Yadav, TC and Gupta, P and Saini, S and Mohiyuddin, S and Pruthi, V and Prasad, R}, title = {Plausible Mechanistic Insights in Biofilm Eradication Potential against Candida spp. Using In Situ-Synthesized Tyrosol-Functionalized Chitosan Gold Nanoparticles as a Versatile Antifouling Coating on Implant Surfaces.}, journal = {ACS omega}, volume = {7}, number = {10}, pages = {8350-8363}, pmid = {35309435}, issn = {2470-1343}, abstract = {In the present study, tyrosol-functionalized chitosan gold nanoparticles (Chi-TY-AuNPs) were prepared as an alternative treatment strategy to combat fungal infections. Various biophysical techniques were used to characterize the synthesized Chi-TY-AuNPs. The antifungal and antibiofilm activities of Chi-TY-AuNPs were evaluated against Candida albicans and C. glabrata, and efforts have been made to elucidate the possible mechanism of action. Chi-TY-AuNPs showed a high fungicidal effect against both sessile and planktonic cells of Candida spp. Additionally, Chi-TY-AuNPs completely eradicated (100%) the mature biofilms of both the Candida spp. FESEM analysis highlighted the morphological alterations in Chi-TY-AuNP-treated Candida biofilm cells. The effect of Chi-TY-AuNPs on the ECM components showed significant reduction in protein content in the C. glabrata biofilm and substantial decrease in extracellular DNA content of both the Candida spp. ROS generation analysis using DCFDA-PI staining showed high ROS levels in both the Candida spp., whereas pronounced ROS production was observed in the Chi-TY-AuNP-treated C. glabrata biofilm. Biochemical analysis revealed decreased ergosterol content in Chi-TY-AuNP-treated C. glabrata cells, while inconsequential changes were observed in C. albican s. Furthermore, the transcriptional expression of selected genes (ergosterol biosynthesis, efflux, sterol importer, and glucan biogenesis) was reduced in C. glabrata in response to Chi-TY-AuNPs except ERG11 and CDR1. Conclusively, the result showed the biofilm inhibition and biofilm eradication efficacy of Chi-TY-AuNPs in both the Candida spp. Findings of the present study manifest Chi-TY-AuNPs as a potential therapeutic solution to Candida biofilm-related chronic infections and overcome biofilm antifungal resistance.}, } @article {pmid35308453, year = {2022}, author = {Eskandarinezhad, M and Barhaghi, MHS and Allameh, K and Sadrhaghighi, A and Katebi, K}, title = {The comparison of calcium hydroxide, curcumin, and Aloe vera antibacterial effects on 6-week-old Enterococcus faecalis biofilm as an intracanal medicament: An in vitro study.}, journal = {Dental research journal}, volume = {19}, number = {}, pages = {14}, pmid = {35308453}, issn = {1735-3327}, abstract = {BACKGROUND: This study aimed to compare the antibacterial effects of calcium hydroxide, curcumin, and Aloe vera as an intracanal medicament on 6-week-old Enterococcus faecalis biofilm.

MATERIALS AND METHODS: In this in vitro study, the solution containing E. faecalis ATCC[®] 29212™ was inserted into the canals of 72 single-rooted teeth to produce biofilm. The samples were divided into four groups, and the antibacterial agent as an intracanal drug was used for 1 week. Calcium hydroxide, curcumin, and A. vera were used as intracanal medicaments in three groups, respectively, and the fourth group was irrigated with normal saline. The collected debris was cultured by spread plate method for the bacterial count by colony count machine, and the number of bacteria in each sample per ml was reported in colony-forming unit per ml (CFU/ml). The data were analyzed using SPSS software. KruskalWallis and MannWhitney U-tests were used for comparison of CFU/ml between the study groups. P <0.05 was considered significant.

RESULTS: The mean CFU/ml in the groups of calcium hydroxide, curcumin, and A. vera were 749.44, 630.55, and 1529.16, respectively. Compared with the control group, curcumin, calcium hydroxide, and A. vera showed 99.5%, 99.41%, and 98.79% antimicrobial effects, respectively. All three groups were significantly effective than the control group (P = 0.023, P = 0.023, and P = 0.024, respectively) but were not significantly different from each other (P = 0.057).

CONCLUSION: All three groups showed significant antibacterial activity compared to the control group, curcumin had the most significant effect, followed by calcium hydroxide and A. vera. Therefore, herbal materials can be considered safe alternatives to synthetic medicaments for intracanal usage.}, } @article {pmid35307548, year = {2022}, author = {Chang, RYK and Li, M and Chow, MYT and Ke, WR and Tai, W and Chan, HK}, title = {A dual action of D-amino acids on anti-biofilm activity and moisture-protection of inhalable ciprofloxacin powders.}, journal = {European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V}, volume = {173}, number = {}, pages = {132-140}, doi = {10.1016/j.ejpb.2022.03.003}, pmid = {35307548}, issn = {1873-3441}, mesh = {Administration, Inhalation ; Aerosols/chemistry ; *Amino Acids/chemistry ; Biofilms ; *Ciprofloxacin/pharmacology ; Dry Powder Inhalers ; Particle Size ; Powders/chemistry ; }, abstract = {Although inhalation powder aerosols of antibiotics have been used to treat respiratory infections caused by Pseudomonas aeruginosa, biofilms are difficult to clear. Ciprofloxacin and D-amino acids (D-Met, D-Trp and D-Phe) were shown to facilitate P. aeruginosa biofilm removal. Spray dried powders for inhalation tend to be amorphous, hence unstable to moisture which causes deterioration in the aerosol performance. Hydrophobic L-amino acids such as leucine can impart moisture protection. In this study, we hypothesized that co-spray dried formulations of ciprofloxacin and hydrophobic D-amino acids will offer the combined benefits of both anti-biofilm and moisture protection properties. Of the three D-amino acids tested, D-Met and D-Trp (at 5 mM) but not D-Phe reduced clinical isolate P. aeruginosa biofilm loads and the extent of biofilm clearance was further enhanced in the presence of ciprofloxacin. Subsequently, ciprofloxacin was spray dried alone or in combination with 30% (w/w) D-Met or D-Trp. The biological and physicochemical properties of the powders were assessed, including the minimum inhibitory concentration, anti-biofilm activity, particle size distribution and morphology, solid-state properties, water sorption, and aerosol performance. The spray dried combination powders were physically stable and inhalable with fine particle fraction (<5 µm) values of 50-57% when aerosolized. The powders exhibited enhanced anti-biofilm activity compared with ciprofloxacin alone. The presence of D-amino acids provided moisture protection, with the recrystallization event shifting from 50% RH to 80% RH in powders containing D-Trp. In conclusion, the use of D-amino acids (D-Met or D-Trp) is an attractive formulation strategy which offers dual benefits of anti-biofilm effect and moisture protection.}, } @article {pmid35307476, year = {2022}, author = {Bijle, MN and Ashraf, U and Abdalla, MM and Neelakantan, P and Yiu, CKY}, title = {Biofilm modulatory response of arginine-fluoride varnish on multi-species biofilm.}, journal = {Journal of dentistry}, volume = {122}, number = {}, pages = {104096}, doi = {10.1016/j.jdent.2022.104096}, pmid = {35307476}, issn = {1879-176X}, mesh = {Arginine/pharmacology ; Biofilms ; *Fluorides/pharmacology ; *Fluorides, Topical/pharmacology ; Humans ; Streptococcus mutans ; }, abstract = {OBJECTIVES: To examine the biofilm modulatory effect of arginine (Arg)-fluoride (F) varnish on multi-species biofilms.

METHODS: Experimental varnishes were prepared by incorporating L-Arg (1, 2, and 4%) in 5% NaF varnish, which served as the control. Multi-species biofilms comprising Streptococcus mutans, Streptococcus sanguinis and Streptococcus gordonii were grown on hydroxyapatite (HA) discs and treated with the Arg and F released from the experimental and control groups. The HA discs with treated biofilms were examined for biofilm composition. The biofilm thickness and live/dead counts were investigated using confocal microscopic imaging, while biofilm polysaccharides, proteins, and extracellular DNA (eDNA) were assessed spectrophotometrically. Bacterial composition in biofilms was analysed using viability real-time quantitative polymerase chain reaction (qPCR). The relative gene expression (RGE) was determined for gtfB, SMU.150, nlmD, arcA, and sagP.

RESULTS: Both the 2 and 4% Arg-NaF groups reduced biofilm thickness, with the 4% Arg-NaF group showing a significantly greater proportion of dead bacteria, followed by 1 and 2% Arg-NaF (p < 0.001). All Arg-NaF groups significantly reduced the carbohydrate content of the biofilm, while the 4% Arg-NaF-treated biofilms demonstrated higher concentration of eDNA and proteins compared to the control NaF (p < 0.001). Expression of gtfB, SMU.150, and nlmD were significantly downregulated in 4% Arg-NaF-treated biofilms; while 2% Arg-NaF enhanced the expression of arcA. Both 2% Arg-NaF and 4% Arg-NaF significantly increased the expression of sagP.

CONCLUSION: The incorporation of L-arginine (2%/4%) enhances the biofilm modulatory effect of 5% NaF varnish through released Arg and F.

CLINICAL SIGNIFICANCE: The study results indicate that Arg-F varnish (at 2%/4% w/v. Arg) has the potential to modulate cariogenic biofilms in high-risk individuals.}, } @article {pmid35307444, year = {2022}, author = {Xia, Y and Zhu, L and Geng, N and Lu, D and Xu, C and Withana, PA and Vithanage, M and Khan, E and Ok, YS}, title = {Nitrogen transformation in slightly polluted surface water by a novel biofilm reactor: Long-term performance and microbial population characteristics.}, journal = {The Science of the total environment}, volume = {829}, number = {}, pages = {154623}, doi = {10.1016/j.scitotenv.2022.154623}, pmid = {35307444}, issn = {1879-1026}, mesh = {Ammonia/chemistry ; Biofilms ; Bioreactors/microbiology ; *Denitrification ; Nitrification ; *Nitrogen ; Oxygen ; Waste Disposal, Fluid/methods ; Wastewater/chemistry ; Water ; }, abstract = {This study proposes a modular floating biofilm reactor (MFBR) for in situ nitrogen removal from slightly polluted water in rivers using enriched indigenous microorganisms. Its main structure is a 60 cm × 60 cm × 90 cm rectangular reactor filled with hackettens. After a 96-day startup, the removal efficiencies of ammonia-N and total N (TN) reached 80% and 25%, respectively, with a hydraulic retention time (HRT) of 10 h, whereas those in a control reactor (without biofilm) were only 4.9% and 0.2%, respectively. The influences of HRT and dissolved oxygen (DO) were also investigated. As a key factor, HRT significantly affected the removal efficiencies of ammonia-N and TN. When HRT was close to the actual value for a river studied (2.4 min), the removal efficiencies of ammonia-N and TN were only 8.7% and 3.1%, respectively. Aeration increased the concentration of DO in water, which enhanced nitrification but inhibited denitrification. When HRT was 2.4 min, aeration intensity was 20 L/min; the ammonia-N and TN removal rates were 9.5 g/(m[2]·d) and 11.3 g/(m[2]·d), respectively. The results of microbial community analysis indicated that the microorganisms forming the biofilm were indigenous bacteria. The findings demonstrated a concept-proof of MFBR, which may be evaluated in scaling up investigation for developing a new methodology for nitrogen removal from slightly polluted surface water in plain river networks.}, } @article {pmid35306745, year = {2022}, author = {Hu, J and Chen, S and Yang, Y and Li, L and Cheng, X and Cheng, Y and Huang, Q}, title = {A Smart Hydrogel with Anti-Biofilm and Anti-Virulence Activities to Treat Pseudomonas aeruginosa Infections.}, journal = {Advanced healthcare materials}, volume = {11}, number = {13}, pages = {e2200299}, doi = {10.1002/adhm.202200299}, pmid = {35306745}, issn = {2192-2659}, mesh = {Aminoglycosides/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria/metabolism ; Biofilms ; Hydrogels/pharmacology ; *Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/physiology ; Quorum Sensing ; Virulence ; Virulence Factors ; }, abstract = {Biofilm is the main culprit of refractory infections and seriously threaten to the human health. Here, a smart hydrogel consisted of norspermidine, aminoglycosides, and oxidized polysaccharide is prepared via the formation of acid-labile imine linkage to treat Pseudomonas aeruginosa biofilm infections in several animal models. The increased acidity caused by bacterial infection triggers the release of norspermidine and aminoglycosides covalently bound with the polymer scaffold. The released norspermidine inhibits biofilm formation and virulence production by regulating the quorum sensing of P. aeruginosa, while the aminoglycoside antibiotics effectively kill the released bacteria. The gel thoroughly inhibits biofilm formation on various medical devices and decreases bacteria pathogenicity. It efficiently inhibits implantation-associated biofilm infections and chronic wound infections, and shows great promise to prevent and treat biofilm-induced refractory infection in clinics.}, } @article {pmid35306457, year = {2022}, author = {Li, N and Quan, X and Zhuo, M and Zhang, X and Quan, Y and Liang, P}, title = {Enhancing methanogenesis of anaerobic granular sludge by incorporating Fe/Fe oxides nanoparticles aided with biofilm disassembly agents and mediating redox activity of extracellular polymer substances.}, journal = {Water research}, volume = {216}, number = {}, pages = {118293}, doi = {10.1016/j.watres.2022.118293}, pmid = {35306457}, issn = {1879-2448}, mesh = {Anaerobiosis ; Bioreactors ; Extracellular Polymeric Substance Matrix/metabolism ; Ferric Compounds ; Methane/metabolism ; *Nanoparticles ; Oxidation-Reduction ; Oxides ; Polymers ; *Sewage ; }, abstract = {Anaerobic granular sludge (AGS) is a promising technology for organic wastewater treatment and energy recovery. In this study, three different kinds of Fe and Fe oxides nanoparticles (Fe3O4, Fe2O3 and ZVI) were tried to be incorporated into AGS through direct loading or aided with biofilm disassembly agents of norspermidine and D-tyrosine, which was aimed to enhance methane production capacity of AGS via increasing redox activity of extracellular polymer substance (EPS) and interspecies electron transfer. Despite the loading methods, incorporation of Fe and Fe oxides nanoparticles into AGS increased methane production capacity remarkably, with an enhancement of 36.49-85.17%, 20.37-204.95% and 189.71-243.32%, respectively, for the Fe3O4, Fe2O3 and ZVI loaded AGS. Pretreatment of AGS using biofilm disassembly agents helped to incorporate more Fe and Fe oxides into the inner structure of AGS, which further enhanced methane production capacity by 48.68% and 184.58%, respectively, for the Fe3O4 and Fe2O3 loaded AGS. Loading Fe and Fe oxides into AGS not only introduced exogenous conductive substances and Fe(III)/Fe(II) redox couples into EPS matrix of AGS, but also stimulated the production of redox active components of flavins and c-Cyts. All these factors may contribute to the reduced resistance of EPS, enhanced interspecies electron transfer and methane production capacity of AGS. This study provides a novel strategy and facile method to accelerate interspecies electron transfer and enhance methane production for matured AGS.}, } @article {pmid35306411, year = {2022}, author = {Xin, K and Chen, X and Zhang, Z and Zhang, Z and Pang, H and Yang, J and Jiang, H and Lu, J}, title = {Trace antibiotics increase the risk of antibiotic resistance genes transmission by regulating the biofilm extracellular polymeric substances and microbial community in the sewer.}, journal = {Journal of hazardous materials}, volume = {432}, number = {}, pages = {128634}, doi = {10.1016/j.jhazmat.2022.128634}, pmid = {35306411}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial/genetics ; *Extracellular Polymeric Substance Matrix ; Genes, Bacterial ; *Microbiota ; Sulfamethoxazole ; Tetracycline/pharmacology ; Wastewater ; }, abstract = {Sewer is considered a potential hotspot for antibiotic resistance, but the occurrence and proliferation of antibiotic resistance genes (ARGs) under trace antibiotics exposure have received little attention. This work evaluated the effects of tetracycline (TC) and sulfamethoxazole (SMX) individually and in combination in the sewer system and revealed the related mechanisms of ARG proliferation. The relative abundance of tetA and sul1 increased the most under TC and SMX stress, respectively, whereas sul1 increased the most under combined stress. Intl1 was abundant in both the liquid phase and the biofilm, and redundancy analysis confirmed that horizontal gene transfer was the main reason for the proliferation of ARGs. The increase in extracellular polymeric substances (EPS) secretion and the enhancement of the main hydrophobic functional groups facilitated the accumulation of biofilms, which promoted the proliferation of ARGs in biofilms. The relative abundance of most ARGs in the liquid phase was significantly correlated with EPS, protein and tryptophan-like substances. Furthermore, the microbial community structure and diversity affected the proliferation and spread of ARGs in the sewer. These findings contribute to our further understanding of the proliferation and development of ARGs in the sewer and lay the foundation for the front-end control of ARGs.}, } @article {pmid35306408, year = {2022}, author = {Jia, T and Zhang, L and Zhao, Q and Peng, Y}, title = {The effect of biofilm growth on the sulfur oxidation pathway and the synergy of microorganisms in desulfurization reactors under different pH conditions.}, journal = {Journal of hazardous materials}, volume = {432}, number = {}, pages = {128638}, doi = {10.1016/j.jhazmat.2022.128638}, pmid = {35306408}, issn = {1873-3336}, mesh = {Bacteria/metabolism ; Biofilms ; *Bioreactors ; Filtration ; *Hydrogen Sulfide/metabolism ; Hydrogen-Ion Concentration ; Oxygen ; Sulfur ; }, abstract = {Biofilm growth affects the oxygen transfer in biofilm and thus the oxidation pathway of sulfur and the synergy of microorganisms. In this study, the effect of biofilm growth on the oxidation pathway of H2S and the synergy of microorganisms in desulfurization reactors under different pH conditions was first discussed to enhance the understanding of desulfurization process. A biotrickling filter (BTF) was operated for 168 days under acidic condition (pH<4.7) and 32 days under alkaline condition (7.0 89.0%). In alkaline period, the AGM raised to 0.97 g/L-BTF/d, and 77.0% of S-H2S was transferred to elemental sulfur (S[0]) and polysulfanes (R-Sx-R) accumulated in biofilm. The increase of biofilm and sulfur-oxidizing bacteria activity limited the oxygen transfer in alkaline biofilm, leading to the accumulation of S[0] and the emergence of an obligate anaerobe- Acetoanaerobium (8.1%). The formation of R-Sx-R may be due to the reaction of S[0] with thiols produced by a thiol-producing bacterium- Pseudomonas (6.7%). The uneven distribution of oxygen in biofilm caused by biofilm growth complicated the transfer pathway of sulfur and the synergy of microorganisms in desulfurization system.}, } @article {pmid35306153, year = {2022}, author = {Sun, J and Sun, Z and Wang, D and Liu, F and Wang, D}, title = {Contribution of ultrasound in combination with chlorogenic acid against Salmonella enteritidis under biofilm and planktonic condition.}, journal = {Microbial pathogenesis}, volume = {165}, number = {}, pages = {105489}, doi = {10.1016/j.micpath.2022.105489}, pmid = {35306153}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Chlorogenic Acid/pharmacology ; *Plankton ; *Salmonella enteritidis ; }, abstract = {The antibacterial and antibiofilm mechanisms of ultrasound combined with chlorogenic acid treatment for Salmonella enteritidis under biofilm and planktonic condition were investigated. S. enteritidis under biofilm and planktonic cells were treated with ultrasound, chlorogenic acid, and their combination for 5, 10, 20, 30, and 60 min. Results showed that the combined treatments exhibited synergistic effects that inactivated the S. enteritidis biofilm and planktonic cells. The nucleic acids and ATP leakage and CLSM imagines showed that the combining chlorogenic acid and ultrasound treatment significantly increased the permeability of the S. enteritidis cell membrane. SEM indicated that the combining chlorogenic acid and ultrasound treatment quickly destroyed the integrity of the S. enteritidis cell membrane, and the activity of respiratory chain dehydrogenase sharply decreased. Additionally, the amounts of polysaccharides in the S. enteritidis biofilms significantly decreased after the combined treatments. Hence, the combining chlorogenic acid and ultrasound treatment have potential applications in food preservation.}, } @article {pmid35306135, year = {2022}, author = {Gong, L and Tong, Y and Yang, H and Feng, S}, title = {Simultaneously pollutant removal and S[0] recovery from composite wastewater containing Cr(VI)-S[2-] based on biofilm enhancement.}, journal = {Bioresource technology}, volume = {351}, number = {}, pages = {127017}, doi = {10.1016/j.biortech.2022.127017}, pmid = {35306135}, issn = {1873-2976}, mesh = {Bacteria/genetics/metabolism ; Biofilms ; Bioreactors/microbiology ; Chromium ; Denitrification ; *Environmental Pollutants/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Nitrogen/metabolism ; *Wastewater/chemistry ; }, abstract = {Bioaugmentation of extracellular polymeric substances-producing bacteria was applied in pollutant removal and S[0] recovery from composite wastewater in a mixotrophic denitrification system. In the presence of 200 mg·L[-1] S[2-] and 50 mg·L[-1] Cr(VI), the removal efficiencies of chemical oxygen demand, NO3[-], S[2-] and Cr(VI) were 86.38%, 91.82%, 95.75%, and 100.00% respectively, while S[0] recovery efficiency reached 79.17%. Increased contents of protein and polysaccharide, especially the high ratio of protein/polysaccharide verified the structural stability of biofilm was promoted by biofilm enhancement. The widespread distribution of bacteria/extracellular polymeric substance (EPS) revealed the more obvious biofilms formation in biofilm-enhanced group. High-throughput sequencing analysis showed that EPS-producing bacteria (Flavobacterium, Thauera, Thiobacillus and Simplicispira) were dominant bacteria in the biofilm-enhanced group. Moreover, by comprehensive considering of redundancy analysis, the colonization of selected bacteria improved the robustness of the reactor and treatment performance to wastewater contained toxic pollutions.}, } @article {pmid35306051, year = {2022}, author = {Wang, L and Wu, Y and Ren, Y and Wang, Y and Wang, Y and Zhang, H}, title = {Transition of fouling characteristics after development of membrane wetting in membrane-aerated biofilm reactors (MABRs).}, journal = {Chemosphere}, volume = {299}, number = {}, pages = {134355}, doi = {10.1016/j.chemosphere.2022.134355}, pmid = {35306051}, issn = {1879-1298}, mesh = {Biofilms ; *Bioreactors ; Membranes, Artificial ; Waste Disposal, Fluid/methods ; *Water Purification ; }, abstract = {The practical applications of water treatment techniques based on hydrophobic aeration membrane are limited due to membrane pores blocking. Various studies have revealed that both biofilm and microbial secretion can exacerbate membrane fouling. Recently, we constructed a membrane-aerated biofilm reactor (MABR) system for treating micro-polluted surface water in order to identify the primary cause for oxygen transfer rate (OTR) decline. It was found that microbial secretion had a more prominent negative effect than that caused by biofilm, as manifested by the fact the effect of microbial secretion (66.49%) was greater than the resistance of biofilm (38.83%). Fouling decreased the total pore volume of all membrane. The peak location of adsorption capacity was more likely to occur at smaller pore sizes with longer running time. Notably, continuous fluorescence distribution between the separating layer and pores like finger in MABR system exhibited an increasing trend with the operation time, indicating a gradual increase of microbial viability. Core protein structure was revealed by different bond peaks (0-90 d). Specifically, for different organic components of EPS, the hydrophilic HIS was the main content, while the mass transfer resistance caused by the gel increased, which reduced the contact angle and increased the bubble point pressure. Therefore, effects of EPS content and composition should be considered during the application of water treatment techniques based on MABR.}, } @article {pmid35306018, year = {2022}, author = {Elmehbad, NY and Mohamed, NA and Abd El-Ghany, NA}, title = {Evaluation of the antimicrobial and anti-biofilm activity of novel salicylhydrazido chitosan derivatives impregnated with titanium dioxide nanoparticles.}, journal = {International journal of biological macromolecules}, volume = {205}, number = {}, pages = {719-730}, doi = {10.1016/j.ijbiomac.2022.03.076}, pmid = {35306018}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/chemistry/pharmacology ; Biofilms ; *Chitosan/chemistry/pharmacology ; Escherichia coli ; Humans ; Microbial Sensitivity Tests ; *Nanoparticles/chemistry ; Staphylococcus aureus ; Titanium/chemistry/pharmacology ; }, abstract = {Two novel chitosan derivatives were prepared by incorporating salicylhydrazide into chitosan Schiff base (SCsSB) and chitosan (SCs). Two nanocomposites, SCs/TiO2-1% and SCs/TiO2-3%, were also prepared. Their structures were confirmed using elemental analyses, FTIR, XRD, SEM, EDX and TEM. Their antimicrobial and anti-biofilm activities were arranged as: SCs/TiO2-3% > SCs/TiO2-1% > SCs > SCsSB > chitosan. SCs showed minimum inhibitory concentration (MIC) value of 1.95 μg/mL against A. niger which was comparable with that of Amphotericin B. SCs/TiO2-3% showed higher inhibition against S. epidermidis, S. aureus, S. pyogenes, P. aeruginosa and E. coli than Vancomycin. While, it showed comparable inhibition activity to that of Vancomycin against B. subtilis and P. mirabilis. SCs/TiO2-3% showed MIC values equal 0.48 and 0.98 μg/mL corresponded to 0.98 and 1.95 μg/mL of Amphotericin B against C. albicans, A. fumigatus and A. niger, respectively. SCs/TiO2-3% showed much lower minimum biofilm inhibitory concentration (MBIC) values, ranged between 1.95 and 7.81 μg/mL, than those of SCs, ranged from 62.5 to 125 μg/mL. SCs/TiO2-3% was safe on normal human cells. The modifiers and TiO2 nanoparticles incorporated into chitosan in one structure developed its performance. It is approach for attaining appropriate structures which are good competitors for antimicrobial agents.}, } @article {pmid35304937, year = {2022}, author = {Subramaniyan, SB and Ameen, F and Singaravelu, DK and Elumalai, P and Bhat, SA and Veerappan, A}, title = {Phytolectin conjugated positively charged fatty acid amide impairs virulence factors and inhibits cross-kingdom biofilm formation of Candida albicans and uropathogenic Escherichia coli.}, journal = {Journal of applied microbiology}, volume = {133}, number = {6}, pages = {3252-3264}, doi = {10.1111/jam.15535}, pmid = {35304937}, issn = {1365-2672}, support = {//King Saud University/ ; //SASTRA University/ ; CRG/2019/003462//Science and Engineering Research Board/ ; }, mesh = {*Uropathogenic Escherichia coli ; Candida albicans ; Virulence Factors ; Amides ; Fatty Acids ; Biofilms ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; }, abstract = {AIM: Polymicrobial biofilm encasing cross-kingdom micro-organisms are apparent in medicine, which imposes serious resistance to conventional antimicrobial treatment. The objective of the study was to explore Butea monosperma seed lectin (BMSL) conjugated antimicrobial lipid, 2-((N-[2-hydroxyethyl]palmitamido)methyl)-1-methylpyridin-1-ium iodide (cN16E) to inhibit mixed-species biofilm of uropathogenic Escherichia coli-Candida albicans.

METHODS AND RESULTS: Antimicrobial activity and antibiofilm of cN16E and cN16E-BMSL conjugate (BcN16E) were analysed against single- and mixed microbial cultures. The minimum inhibitory concentration (MIC) indicates that the MIC of cN16E-BMSL conjugate (BcN16E) against cohabiting UPEC-C. albicans was eightfold lower than the cN16E. BcN16E affects membrane integrity to elicit antimicrobial activity. BcN16E inhibits the dual-species biofilm even with 16 times lower MIC of cN16E. BcN16E impairs the biofilm-associated virulence factors which include extracellular polysaccharides, cell surface hydrophobicity, swimming, swarming motilities, hyphal filamentous morphology, curli formation and haemolysin activity. As a proof of concept, we demonstrated BcN16E ability to inhibit dual-species biofilm formation on a urinary catheter.

CONCLUSION: The study revealed that the BcN16E is better than cN16E in impairing biofilm-associated virulence factors and exerting antimicrobial activity.

The findings emphasize that phytolectin has the potential to enhance the anti-virulence strategies of antimicrobials against cross-kingdom biofilm-related infections.}, } @article {pmid35304533, year = {2022}, author = {Li, J and Zhang, C and Hu, X and Yoshida, A and Osatomi, K and Guo, X and Yang, JL and Liang, X}, title = {Impact of different enzymes on biofilm formation and mussel settlement.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {4685}, pmid = {35304533}, issn = {2045-2322}, mesh = {Animals ; Bacterial Proteins/pharmacology ; Biofilms ; *Mytilus/microbiology ; }, abstract = {Enzymes have been known to impact the biofilm forming capacity. However, how the enzymes mediate the biofilm formation and macrofouling remains little known. Here, we investigated the effects of the three kinds of proteases, four kinds of glycosidases and one kind of lipase on the detachment of biofilms of Shewanella marisflavi ECSMB14101, identified biofilm total proteins response to enzyme treatments, and then tested the effects of biofilms treated with enzymes on the settlement of the mussel Mytilus coruscus plantigrades. The results showed that the cell density of bacteria in biofilms formed at different initial bacterial density were noticeably reduced after treating with all tested enzymes, and Neutrase and α-Amylase exhibited best removing efficiency of > 90%. Bacterial total proteins in S. marisflavi biofilm noticeably reduced or disappeared after treated by Alcalase. For the settlements of the mussel M. coruscus plantigrades, inducing capacities of S. marisflavi biofilm were noticeably suppressed and downregulation was > 75% at the initial density of 5 × 10[6] cells/cm[2]. Thus, the tested enzymes could effectively remove the adhered bacterial cell, inhibit the biofilm formation and finally suppress the mussel settlement. Our findings extend novel knowledge to developing eco-friendly approach to control micro- and macro-fouling.}, } @article {pmid35304219, year = {2022}, author = {Chen, Y and Wang, J and Zhao, YG and Maqbool, F and Gao, M and Guo, L and Ji, J and Zhao, X and Zhang, M}, title = {Sulfamethoxazole removal from mariculture wastewater in moving bed biofilm reactor and insight into the changes of antibiotic and resistance genes.}, journal = {Chemosphere}, volume = {298}, number = {}, pages = {134327}, doi = {10.1016/j.chemosphere.2022.134327}, pmid = {35304219}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Bioreactors ; Genes, Bacterial ; *Sulfamethoxazole/pharmacology ; *Wastewater ; }, abstract = {Antibiotics are widely dosed in mariculture sector, resulting in substantial antibiotics residues. Hence, mariculture wastewater is urgent to be treated before discharging. In this study, the anoxic/oxic moving bed biofilm reactor (A/O-MBBR) was used to treat the wastewater containing sulfamethoxazole (SMX) from mariculture, SMX removal mechanism and the variation of antibiotic-resistant genes (ARGs) were investigated. The results showed that 22%-33% of SMX was removed by the bioreactor, where a small amount of SMX was adsorbed and stored by the extracellular polymers and most of SMX (>80%) was biodegraded in the anoxic tank. Occurrence of nitrate in anoxic condition was conducive to SMX degradation. Pseudomonas, Desulfuromusa, and Methanolobus species, as well as microbial catalase contributed to the SMX biotransformation. Quantitative PCR analysis of ARGs (sul1, sul2 and int1) and mRNA (sul1, sul2) showed that SMX enriched SMX-related ARGs and enhanced the expression of corresponding genes. Most of ARGs finally were discharged with effluent. Hence, the effluent from biologically based processes treating mariculture wastewater still contained antibiotics residue and resistance genes, which should be further controlled by suitable techniques.}, } @article {pmid35303638, year = {2022}, author = {Wang, Q and Qiu, W and Li, M and Li, N and Li, X and Qin, X and Wang, X and Yu, J and Li, F and Huang, L and Wu, D}, title = {Multifunctional hydrogel platform for biofilm scavenging and O2 generating with photothermal effect on diabetic chronic wound healing.}, journal = {Journal of colloid and interface science}, volume = {617}, number = {}, pages = {542-556}, doi = {10.1016/j.jcis.2022.03.040}, pmid = {35303638}, issn = {1095-7103}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Diabetes Mellitus ; Humans ; Hydrogels/pharmacology ; Hydrogen Peroxide ; Hypoxia ; *Manganese Compounds ; Oxides ; Oxygen ; Wound Healing ; }, abstract = {Diabetic wound treatment remains a major challenge due to the difficulties of eliminating bacterial biofilm and relieving wound hypoxia. To address these issues simultaneously, a multifunctional Dex-SA-AEMA/MnO2/PDA (DSAMP) hydrogel platform was developed with excellent biocompatibility and porous structure. The hydrogel could absorb the exudate, maintain humidity and permeate oxygen, which was prepared by encapsulating polydopamine (PDA) and manganese dioxide (MnO2) into Dex-SA-AEMA (DSA) hydrogel by UV irradiation. With the addition of PDA, the DSAMP hydrogel was proved to eliminate the biofilm after NIR photodynamic therapy (PTT, 808 nm) irradiation at 54 °C. Furthermore, in order to mitigate hypoxia wound microenvironment, MnO2 nanoparticles were added to convert the endogenous hydrogen peroxide (H2O2) into oxygen (O2, 16 mg L[-1]). The diabetic wound in vivo treated by DSAMP hydrogel was completely healed on 14 days. It was revealed that the DSAMP hydrogel possessed a great potential as dressing for diabetic chronic wound healing.}, } @article {pmid35302726, year = {2022}, author = {Singh, D and Singh, V and Bhushan Mishra, S and Sharma, D and Agarwal, V}, title = {Evaluation of anti-biofilm, anti-quorum, anti-dysenteric potential of designed polyherbal formulation: in vitro and in vivo study.}, journal = {Journal of applied biomedicine}, volume = {20}, number = {1}, pages = {7-14}, pmid = {35302726}, issn = {1214-0287}, mesh = {Animals ; Biofilms ; *Dysentery, Bacillary ; Escherichia coli ; Microbial Sensitivity Tests ; Quorum Sensing ; Rats ; }, abstract = {Bacillary dysentery (shigellosis) continues to cause havoc worldwide, with a high infectivity rate. It causes bloody diarrhea, and around 99% of bacillary dysentery cases occur in developing countries. The objective of this study is to develop a polyherbal formulation with the scientific rationale in treating infectious bacillary dysentery disease. The anti-bacterial activity, the minimum inhibitory concentration of the formulation against bacillary dysentery, causing microbes like Shigella flexneri (MTCC 1457), Escherichia coli (MTCC 1687), and Salmonella enterica (MTCC 98), was analysed by well-diffusion method and broth dilution method, respectively. The biofilm inhibition activity was determined on 96 well polystyrene plates and anti-quorum sensing activity by Chromobacterium violaceum CV026. The cytotoxicity was examined by acute oral toxicity. Excreta and organ bacterial load were analyzed by serial dilution method. The formulation efficacy was determined by analyzing the blood sample of rats. The antimicrobial efficacy of the developed formulation was calculated by measuring the zone of inhibition which was found to be 24 mm, 25 mm, and 25 mm, and the MIC values of 1.5 mg/ml, 1.5 mg/ml, and 2.0 mg/ml against S. flexneri, S. enterica, E. coli, respectively. The results show that the polyherbal formulation significantly reduced biofilm formation and has anti-quorum sensing activity. The formulation also effectively decreases the bacterial load and increases the K+, Na+, and Ca++ ions in animals treated with the formulation. The developed formulation was found to be non-toxic and effective against bacillary dysentery; thus, it can be used for treating bacillary dysentery and related complications.}, } @article {pmid35302222, year = {2022}, author = {Li, XF and Shi, HQ and Liang, Y and Li, J and Jiang, B and Song, GB}, title = {Interaction of biofilm and efflux pump in clinical isolates of carbapenem resistant P. aeruginosa.}, journal = {European review for medical and pharmacological sciences}, volume = {26}, number = {5}, pages = {1729-1737}, doi = {10.26355/eurrev_202203_28242}, pmid = {35302222}, issn = {2284-0729}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Outer Membrane Proteins/genetics/metabolism/pharmacology ; Biofilms ; *Carbapenems/pharmacology ; Membrane Transport Proteins/genetics/metabolism/pharmacology ; Microbial Sensitivity Tests ; *Pseudomonas aeruginosa/genetics ; }, abstract = {OBJECTIVE: Carbapenem-resistant P. aeruginosa (CRPA) is particularly worrisome because of its resistance against multiple antimicrobial agents which reduces treatment options. The efflux pump decreases antibiotic abundance, and biofilm impairs the penetration of antibiotics. The aim of the present study was to evaluate the role and relationship of efflux pump and biofilm formation in CRPA isolates obtained from different clinical samples.

PATIENTS AND METHODS: A total of 110 different clinical samples were collected from three tertiary medical hospitals. The samples were subjected to isolation and identification by standard operating procedures. Species level were identified using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system. Antibiotic susceptibility testing was done by broth microdilution method. Crystal violet (CV) staining for observing the biofilm forming ability and amplification of efflux pump mexA gene were also performed on clinical CRPA isolates. Three efflux pump MexAB-OprM regulatory genes were analyzed using sequencing methods. The expression of mexA gene both in biofilm and planktonic bacteria was observed by Quantitative real-time PCR (qRT-PCR).

RESULTS: The results showed that 110 samples were CRPA and among them 83 (75.5%) were MDR isolates. The CV staining showed 105 (95.5%) isolates as biofilm producers while 78 (74.3%) MDR isolates showed biofilm formation. mexA hyperexpression was detected in 27 (24.5%) CRPA isolates while 26 (96.3%) in biofilm forming isolates and 96.3% (26/27) in MDR P. aeruginosa. Multiple mutations in nalC, nalD, and mexR genes were detected. The distinct difference confirmed that the expression of mexA gene in P. aeruginosa biofilm producer was significantly higher than that of planktonic bacteria in vitro, and the efflux pump inhibitor PAβN significantly inhibited biofilms in CRPA isolated from clinical samples.

CONCLUSIONS: The biofilm and efflux pumps might be two intertwined processes involved in CRPA isolates. Their synergistic effect magnified the drug resistance characteristics of P. aeruginosa.}, } @article {pmid35301694, year = {2022}, author = {Arendse, M and Khan, S and Wani, MY and Aqlan, FM and Al-Bogami, AS and Ahmad, A}, title = {Quorum Sensing and Biofilm Disrupting Potential of Imidazole Derivatives in Chromobacterium violaceum Using Antimicrobial and Drug Discovery Approaches.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {2}, pages = {565-582}, pmid = {35301694}, issn = {1678-4405}, support = {RDYR180418322304//National Research Foundation/ ; AZMD019//University of the Witwatersrand, Johannesburg/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/pharmacology ; Antifungal Agents/pharmacology ; Biofilms ; Chromobacterium/genetics ; Drug Discovery ; Imidazoles/pharmacology ; Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {Population of drug-resistant bacteria have increased at an alarming rate in the past few decades. The major reason for increasing drug resistance is the lack of new antibiotics and limited drug targets. It has therefore been a vital task to develop new antibiotics with different drug targets. Two such targets are biofilm formation and quorum sensing. Quorum sensing is cell to cell communication used by bacteria that initiates many important survival processes and aids in establishing pathogenesis. Both biofilm and quorum sensing are inter-related processes and play a major role in physiological and pathogenesis processes. In this study, five novel imidazole derivatives (IMA-1-IMA-5) were synthesised and tested for their antibacterial and anti-quorum sensing activities against Chromobacterium violaceum using different in silico and in vitro techniques following the standard protocols. In silico results revealed that all compounds were able to effectively bind to and interact sufficiently with the target protein CviR. CviR is a protein to which autoinducers bind to initiate the quorum sensing process. In silico results also revealed that the compounds generated favourable structural dynamics implying that the compounds would be able to effectively bind to CviR and inhibit quorum sensing. Susceptibility results revealed that IMA-1 is the most active of all the derivatives against both planktonic cells and biofilms. Qualitative and quantitative evaluation of anti-quorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for IMA-1. Down-regulation of most of the quorum sensing genes when cells were treated with the test compounds affirmed the high anti-quorum sensing activities of these compounds. The results from this study are promising and urges on the use of anti-quorum sensing and biofilm disrupting molecules to combat multi-drug resistance problem.}, } @article {pmid35300800, year = {2022}, author = {Nguyen, AT and Goswami, S and Ferracane, J and Koley, D}, title = {Real-time monitoring of the pH microenvironment at the interface of multispecies biofilm and dental composites.}, journal = {Analytica chimica acta}, volume = {1201}, number = {}, pages = {339589}, pmid = {35300800}, issn = {1873-4324}, support = {R01 DE027999/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; *Composite Resins ; Glass ; Hydrogen-Ion Concentration ; Mouth ; }, abstract = {Bacterial-mediated local pH change plays an important role in altering the integrity of resin dental composite materials in a dynamic environment such as the oral cavity. To address this, we developed a 300-μm-diameter, flexible, solid-state potentiometric pH microsensor capable of detecting and quantifying the local pH microenvironment at the interface of multispecies biofilm and dental resin in real time over 10 days. We used fluorinated poly(3,4-ethylenedioxythiophene) as the back contact in our newly developed pH sensor, along with a PVC-based ion-selective membrane and PTFE-AF coating. The high temporal resolution pH data demonstrated pH changes from 7 to 6 and 7 to 5.8 for the first 2 days and then fluctuated between 6.5 to 6 and 6 to 5.5 for the remaining 8 days with the resin composite or glass slide substrate respectively. We could observe the fluctuations in pH mediated by lactic acid production within the biofilm and the re-establishment of pH back to 7. However, acid production started to overwhelm buffering capacity with the continuous feed of sucrose cycles and reduced the local pH nearer to 5.5. No such changes or fluctuations were observed above the biofilm, as the pH remained at 7.0 ± 0.2 for 10 days. The localized real-time monitoring of the pH within the biofilm showed that the pH shift underneath the biofilm could lead to damage to the underlying material and their interface but cannot be sensed external to the biofilm.}, } @article {pmid35300476, year = {2022}, author = {Yao, S and Hao, L and Zhou, R and Jin, Y and Huang, J and Wu, C}, title = {Formation of Biofilm by Tetragenococcus halophilus Benefited Stress Tolerance and Anti-biofilm Activity Against S. aureus and S. Typhimurium.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {819302}, pmid = {35300476}, issn = {1664-302X}, abstract = {Tetragenococcus halophilus, a halophilic lactic acid bacterium (LAB), plays an important role in the production of high-salt fermented foods. Generally, formation of biofilm benefits the fitness of cells when faced with competitive and increasingly hostile fermented environments. In this work, the biofilm-forming capacity of T. halophilus was investigated. The results showed that the optimal conditions for biofilm formation by T. halophilus were at 3-9% salt content, 0-6% ethanol content, pH 7.0, 30°C, and on the surface of stainless steel. Confocal laser scanning microscopy (CLSM) analysis presented a dense and flat biofilm with a thickness of about 24 μm, and higher amounts of live cells were located near the surface of biofilm and more dead cells located at the bottom. Proteins, polysaccharides, extracellular-DNA (eDNA), and humic-like substances were all proved to take part in biofilm formation. Higher basic surface charge, greater hydrophilicity, and lower intracellular lactate dehydrogenase (LDH) activities were detected in T. halophilus grown in biofilms. Atomic force microscopy (AFM) imaging revealed that biofilm cultures of T. halophilus had stronger surface adhesion forces than planktonic cells. Cells in biofilm exhibited higher cell viability under acid stress, ethanol stress, heat stress, and oxidative stress. In addition, T. halophilus biofilms exhibited aggregation activity and anti-biofilm activity against Staphylococcus aureus and Salmonella Typhimurium. Results presented in the study may contribute to enhancing stress tolerance of T. halophilus and utilize their antagonistic activities against foodborne pathogens during the production of fermented foods.}, } @article {pmid35300379, year = {2022}, author = {Paulitsch-Fuchs, AH and Bödendorfer, B and Wolrab, L and Eck, N and Dyer, NP and Lohberger, B}, title = {Effect of Cobalt-Chromium-Molybdenum Implant Surface Modifications on Biofilm Development of S. aureus and S. epidermidis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {837124}, pmid = {35300379}, issn = {2235-2988}, mesh = {Biofilms ; Chromium/pharmacology ; Cobalt/pharmacology ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Molybdenum/pharmacology ; *Staphylococcal Infections ; Staphylococcus aureus/genetics ; Staphylococcus epidermidis ; }, abstract = {Periprosthetic infections are an eminent factor in patient care and also having significant economic implications. The number of biofilm-infection related replacement surgeries is increasing and will continue to do so in the following decades. To reduce both the health burden of the patients and the costs to the healthcare sector, new solutions for implant materials resistant to such infections are necessary. This study researches different surface modifications of cobalt-chromium-molybdenum (CoCrMo) based implant materials and their influence on the development of biofilms. Three smooth surfaces (CoCrMo, CoCrMo TiN, and CoCrMo polished) and three rough surfaces (CoCrMo porous coated, CoCrMo cpTi, and CoCrMo TCP) are compared. The most common infectious agents in periprosthetic infections are Staphylococcus aureus and Coagulase-negative staphylococci (e.g., Staphylococcus epidermidis), therefore strains of these two species have been chosen as model organisms. Biofilms were grown on material disks for 48 h and cell number, polysaccharide content, and protein contend of the biofilms were measured. Additionally, regulation of genes involved in early biofilm development (S. aureus icaA, icaC, fnbA, fnbB, clfB, atl; S. epidermidis atlE, aap) was detected using RT-q-PCR. All results were compared to the base alloy without modifications. The results show a correlation between the surface roughness and the protein and polysaccharide content of biofilm structures and also the gene expression of the biofilms grown on the different surface modifications. This is supported by the significantly different protein and polysaccharide contents of the biofilms associated with rough and smooth surface types. Additionally, early phase biofilm genes (particularly icaA, icaC, and aap) are statistically significantly downregulated compared to the control at 48 h on rough surfaces. CoCrMo TiN and polished CoCrMo were the two smooth surface modifications which performed best on the basis of low biofilm content.}, } @article {pmid35298927, year = {2022}, author = {Talank, N and Morad, H and Barabadi, H and Mojab, F and Amidi, S and Kobarfard, F and Mahjoub, MA and Jounaki, K and Mohammadi, N and Salehi, G and Ashrafizadeh, M and Mostafavi, E}, title = {Bioengineering of green-synthesized silver nanoparticles: In vitro physicochemical, antibacterial, biofilm inhibitory, anticoagulant, and antioxidant performance.}, journal = {Talanta}, volume = {243}, number = {}, pages = {123374}, doi = {10.1016/j.talanta.2022.123374}, pmid = {35298927}, issn = {1873-3573}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Anticoagulants/pharmacology ; Antioxidants/chemistry/pharmacology ; Bioengineering ; Biofilms ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry ; *Silver/chemistry/pharmacology ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus ; }, abstract = {Green-synthesized nanobiomaterials can be engineered as smart nanomedicine platforms for diagnostic and therapeutic purposes in medicine. Herein, we investigated the bioengineering of silver nanoparticles (AgNPs) and evaluated their physicochemical, antibacterial, biofilm inhibitory, anticoagulant, and antioxidant performance. Characterization of the AgNPs was performed utilizing UV-visible, transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR). The spherical shaped AgNPs were proven by TEM and SEM techniques. Moreover, the XRD diffraction patterns demonstrated that the nanoparticles were in a crystalline state. The DLS represented the hydrodynamic particle size of the NPs at 49.62 nm at a pH of 9. The calculated minimum inhibitory concentration (MIC) of AgNPs toward Staphylococcus aureus (ATCC 25923) was 8 μg mL[-1], which was almost similar to tetracycline by the value of 4 μg mL[-1]. Moreover, the minimum bactericidal concentration (MBC) of AgNPs was 64 μg mL[-1], which was significantly less than the determined value of 256 μg mL[-1] for tetracycline. Considering the pathogenic and standard S. aureus, the evaluated concentrations of AgNPs and tetracycline showed significant biofilm inhibitory performance. Furthermore, the bioengineered AgNPs exhibited significant anticoagulant activity at 500 μg mL[-1] compared to saline (P < 0.001). In addition, the biogenic AgNPs inhibited 69.73 ± 0.56% of DPPH free radicals at 500 μg mL[-1], indicating considerable antioxidant potential.}, } @article {pmid35295756, year = {2022}, author = {Mateus, T and Seppanen, EJ and de Gier, C and Clark, S and Coates, H and Vijayasekaran, S and Prosser, K and Wiertsema, SP and Fuery, A and Kirkham, LS and Richmond, PC and Thornton, RB}, title = {Sleep Disordered Breathing and Recurrent Tonsillitis Are Associated With Polymicrobial Bacterial Biofilm Infections Suggesting a Role for Anti-Biofilm Therapies.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {831887}, pmid = {35295756}, issn = {2235-2988}, mesh = {Biofilms ; Child ; Humans ; RNA, Ribosomal, 16S ; *Sleep Apnea Syndromes ; Staphylococcus aureus/genetics ; *Tonsillitis/drug therapy/microbiology/surgery ; }, abstract = {BACKGROUND: The underlying pathogenesis of pediatric obstructive sleep disordered breathing (SDB) and recurrent tonsillitis (RT) are poorly understood but need to be elucidated to develop less invasive treatment and prevention strategies.

METHODS: Children aged between 1- and 16-years undergoing adenoidectomy, tonsillectomy or adenotonsillectomy for SDB (n=40), RT alone (n=18), or both SDB and RT (SDB+RT) (n=17) were recruited with age-matched healthy controls (n=33). Total bacterial load and species-specific densities of nontypeable Haemophilus influenzae (NTHi), Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae and Moraxella catarrhalis were measured by qPCR in nasopharyngeal swabs, oropharyngeal swabs, adenoid and tonsillar tissue from children with SDB, SDB+RT and RT, and in naso- and oro- pharyngeal swabs from healthy children. A subset of tonsil biopsies were examined for biofilms using 16S rRNA FISH (n=3/group).

RESULTS: The 5 bacterial species were detected in naso- and oro- pharyngeal samples from all children. These species were frequently detected in adenotonsillar tissue (except S. aureus, which was absent in adenoids) from children with SDB, SDB+RT and RT. NTHi and S. aureus were observed in tonsils from 66.7-88.2% and 33.3-58.8% of children respectively. Similar total and species-specific bacterial densities were observed in adenotonsillar tissue from children with SDB, SDB+RT or RT. Nasopharyngeal and oropharyngeal swabs were more likely to have multiple bacterial species co-detected than adenotonsillar tissue where one or two targeted species predominated. Polymicrobial biofilms and intracellular bacteria were observed in tonsils from children with adenotonsillar disease.

CONCLUSIONS: Antimicrobials, particularly anti-biofilm therapies, may be a strategy for managing children with SDB.}, } @article {pmid35295755, year = {2022}, author = {Thöming, JG and Häussler, S}, title = {Pseudomonas aeruginosa Is More Tolerant Under Biofilm Than Under Planktonic Growth Conditions: A Multi-Isolate Survey.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {851784}, pmid = {35295755}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; Microbial Sensitivity Tests ; Plankton ; *Pseudomonas Infections/microbiology ; *Pseudomonas aeruginosa/physiology ; Tobramycin/pharmacology ; }, abstract = {Biofilm-associated bacteria exhibit profound changes in bacterial physiology. They thrive in the environment but also in the human host in protected sessile communities. Antimicrobial therapy usually fails, despite the absence of genotypic resistance, and it is commonly accepted that biofilm-grown bacteria are up to 1,000-fold more resistant than planktonic cells. We are only at the beginning to understand the reasons for biofilm recalcitrance, and systematic approaches to describe biofilm-induced tolerance phenotypes are lacking. In this study, we investigated a large and highly diverse collection of 352 clinical Pseudomonas aeruginosa isolates for their antimicrobial susceptibility profiles under biofilm growth conditions towards the antibiotics ciprofloxacin, tobramycin, and colistin. We discovered characteristic patterns of drug-specific killing activity and detected conditional tolerance levels far lower (in the range of the minimal inhibitory concentration (MIC)), but also far higher (up to 16,000-fold increase compared to planktonic cells) than generally believed. This extremely broad distribution of biofilm-induced tolerance phenotypes across the clinical isolates was greatly influenced by the choice of the antibiotic. We furthermore describe cross-tolerance against ciprofloxacin and tobramycin, but not colistin, and observed an additive activity between biofilm-induced tolerance and genetically determined resistance. This became less evident when the biofilm-grown cells were exposed to very high antibiotic concentrations. Although much more remains to be learned on the molecular mechanisms underlying biofilm-induced tolerance, our data on intra-species variations in tolerance profiles provide valuable new insights. Furthermore, our observation that colistin appears to act independently of the tolerance mechanisms of individual clinical strains could make colistin a valuable therapeutic option in chronic biofilm-associated infections characterized by the presence of particularly tolerant strains.}, } @article {pmid35295305, year = {2022}, author = {Alves-Barroco, C and Rivas-García, L and Fernandes, AR and Baptista, PV}, title = {Light Triggered Enhancement of Antibiotic Efficacy in Biofilm Elimination Mediated by Gold-Silver Alloy Nanoparticles.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {841124}, pmid = {35295305}, issn = {1664-302X}, abstract = {Bacterial biofilm is a tri-dimensional complex community of cells at different metabolic stages involved in a matrix of self-produced extracellular polymeric substances. Biofilm formation is part of a defense mechanism that allows the bacteria to survive in hostile environments, such as increasing resistance or tolerance to antimicrobial agents, causing persistent infections hard to treat and impair disease eradication. One such example is bovine mastitis associated with Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), whose worldwide health and economic impact is on the surge. As such, non-conventional nanobased approaches have been proposed as an alternative to tackle biofilm formation and to which pathogenic bacteria fail to adapt. Among these, metallic nanoparticles have gained significant attention, particularly gold and silver nanoparticles, due to their ease of synthesis and impact against microorganism growth. This study provides a proof-of-concept investigation into the use of gold-silver alloy nanoparticles (AuAgNPs) toward eradication of bacterial biofilms. Upon visible light irradiation of AuAgNPs there was considerable disturbance of the biofilms' matrix. The hindering of structural integrity of the biofilm matrix resulted in an increased permeability for entry of antibiotics, which then cause the eradication of biofilm and inhibit subsequent biofilm formation. Additionally, our results that AuAgNPs inhibited the formation of SDSD biofilms via distinct stress pathways that lead to the downregulation of two genes critical for biofilm production, namely, brpA-like encoding biofilm regulatory protein and fbpA fibronectin-binding protein A. This study provides useful information to assist the development of nanoparticle-based strategies for the active treatment of biofilm-related infections triggered by photoirradiation in the visible.}, } @article {pmid35293508, year = {2022}, author = {Campos, FAT and Caldas, ATL and Santos, CAOD and Silva, SA and Vieira, APSB and Viana Filho, JMC and Buzalaf, MAR and Sampaio, FC and Cardoso, CAB}, title = {Effect of dentifrices with different pH and fluoride concentrations on fluoride levels in biofilm and nails: an RCT.}, journal = {Brazilian oral research}, volume = {36}, number = {}, pages = {e043}, doi = {10.1590/1807-3107bor-2022.vol36.0043}, pmid = {35293508}, issn = {1807-3107}, mesh = {Biofilms ; Child ; Child, Preschool ; *Dentifrices ; *Fluorides ; Humans ; Hydrogen-Ion Concentration ; Nails ; }, abstract = {PURPOSE: to evaluate the effect of dentifrice pH and fluoride concentration ([F]) on fluoride uptake on the biofilm and nails of children from a non-fluoridated area.

METHODS: two hundred and twenty-eight two- to four-year-old children were randomly allocated into 3 groups according to the type of dentifrice: G1: 1100 μg F/g, pH 4.5 (n = 76); G2: 750 μg F/g, pH 4.5 (n = 74); and G3: 1100 μg F/g, pH 7.0 (n = 78). Nails were collected at 4, 8, and 12 months after starting dentifrice use and biofilm was collected 5 and 60 minutes after toothbrushing. The concentrations of F in nails and biofilm were analyzed by HMDS facilitated diffusion. Data were analyzed by Kruskal-Wallis/Mann-Whitney's test and the comparison between biofilm collection times was done using Wilcoxon test (p £ 0.05).

RESULTS: a significant reduction of [F] in biofilm was observed 60 minutes after toothbrushing, regardless of the dentifrice used. However, 5 minutes after toothbrushing, G1 had a significantly higher [F] compared to G2 and G3, and 60 minutes after toothbrushing, [F] was significantly higher for G1 and G2 compared to G3. G1 and G3 had significantly higher [F] in the nails compared to G2.

CONCLUSION: a lower dentifrice concentration is a relevant factor for the reduction of excessive fluoride intake. The use of a low-F acidified dentifrice combines the reduction of fluoride uptake with caries prevention by leading to greater incorporation of F into the biofilm over time.}, } @article {pmid35293471, year = {2022}, author = {Santos, ALSD}, title = {Brazilian scientists: much to learn from the microbial biofilm lifestyle (a resistant, resilient, well-orchestrated, and dynamic organization).}, journal = {Ciencia & saude coletiva}, volume = {27}, number = {3}, pages = {947-950}, doi = {10.1590/1413-81232022273.22982021}, pmid = {35293471}, issn = {1678-4561}, mesh = {*Biofilms ; Brazil ; Humans ; *Life Style ; }, abstract = {In the present perspective, some parallels are drawn between a career as a scientist in Brazil and the ability of microorganisms to form a biofilm. Do these connections really exist? Definitely the answer is YES. Over billions of years, microbial biofilms have evolved in order to form a cohesive, well-structured, organized and dynamic community, which is characterized by its resistant/resilient profile to several environmental stressors. Adapting to constant change is a necessary attribute for survival and perpetuation of all live organisms, which are key signatures present in the hereditary molecule. Brazilian scientists are faced with many stressful situations along their journey in academia, which requires constant adaptability, reorganization and, above all, resilience. Can we take some lessons from what we know about the biofilm lifestyle developed by microorganisms? The answer is yes!}, } @article {pmid35290120, year = {2022}, author = {Secchi, E and Savorana, G and Vitale, A and Eberl, L and Stocker, R and Rusconi, R}, title = {The structural role of bacterial eDNA in the formation of biofilm streamers.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {12}, pages = {e2113723119}, pmid = {35290120}, issn = {1091-6490}, mesh = {Bacteria/genetics ; *Biofilms ; DNA, Bacterial/genetics ; Polysaccharides, Bacterial ; *Pseudomonas aeruginosa/genetics ; }, abstract = {Across diverse habitats, bacteria are mainly found as biofilms, surface-attached communities embedded in a self-secreted matrix of extracellular polymeric substances (EPS), which enhance bacterial recalcitrance to antimicrobial treatment and mechanical stresses. In the presence of flow and geometric constraints such as corners or constrictions, biofilms can take the form of long, suspended filaments (streamers), which bear important consequences in industrial and clinical settings by causing clogging and fouling. The formation of streamers is thought to be driven by the viscoelastic nature of the biofilm matrix. Yet, little is known about the structural composition of streamers and how it affects their mechanical properties. Here, using a microfluidic platform that allows growing and precisely examining biofilm streamers, we show that extracellular DNA (eDNA) constitutes the backbone and is essential for the mechanical stability of Pseudomonas aeruginosa streamers. This finding is supported by the observations that DNA-degrading enzymes prevent the formation of streamers and clear already formed ones and that the antibiotic ciprofloxacin promotes their formation by increasing the release of eDNA. Furthermore, using mutants for the production of the exopolysaccharide Pel, an important component of P. aeruginosa EPS, we reveal an concurring role of Pel in tuning the mechanical properties of the streamers. Taken together, these results highlight the importance of eDNA and of its interplay with Pel in determining the mechanical properties of P. aeruginosa streamers and suggest that targeting the composition of streamers can be an effective approach to control the formation of these biofilm structures.}, } @article {pmid35289951, year = {2022}, author = {Bremer, E and Hoffmann, T and Dempwolff, F and Bedrunka, P and Bange, G}, title = {The many faces of the unusual biofilm activator RemA.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {44}, number = {5}, pages = {e2200009}, doi = {10.1002/bies.202200009}, pmid = {35289951}, issn = {1521-1878}, mesh = {Animals ; Bacillus subtilis/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; *Gene Expression Regulation, Bacterial ; *Lepidoptera ; Transcription Factors/metabolism ; }, abstract = {Biofilms can be viewed as tissue-like structures in which microorganisms are organized in a spatial and functional sophisticated manner. Biofilm formation requires the orchestration of a highly integrated network of regulatory proteins to establish cell differentiation and production of a complex extracellular matrix. Here, we discuss the role of the essential Bacillus subtilis biofilm activator RemA. Despite intense research on biofilms, RemA is a largely underappreciated regulatory protein. RemA forms donut-shaped octamers with the potential to assemble into dimeric superstructures. The presumed DNA-binding mode suggests that RemA organizes its target DNA into nucleosome-like structures, which are the basis for its role as transcriptional activator. We discuss how RemA affects gene expression in the context of biofilm formation, and its regulatory interplay with established components of the biofilm regulatory network, such as SinR, SinI, SlrR, and SlrA. We emphasize the additional role of RemA played in nitrogen metabolism and osmotic-stress adjustment.}, } @article {pmid35289361, year = {2022}, author = {Kirchhoff, L and Dittmer, S and Furnica, DT and Buer, J and Steinmann, E and Rath, PM and Steinmann, J}, title = {Inhibition of azole-resistant Aspergillus fumigatus biofilm at various formation stages by antifungal drugs, including olorofim.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {6}, pages = {1645-1654}, doi = {10.1093/jac/dkac062}, pmid = {35289361}, issn = {1460-2091}, mesh = {Acetamides ; Amphotericin B/pharmacology ; *Antifungal Agents/therapeutic use ; *Aspergillus fumigatus ; Azoles/pharmacology ; Biofilms ; Drug Resistance, Fungal ; Fungal Proteins/metabolism ; Microbial Sensitivity Tests ; Piperazines ; Pyrimidines ; Pyrroles ; Voriconazole/metabolism/pharmacology ; }, abstract = {OBJECTIVES: Interest in aspergillosis has increased over the past decades. An increase in the incidence of azole-resistant Aspergillus fumigatus strains has been reported; therefore, the need for novel therapeutic approaches is urgent. The formation of biofilms contributes to pathogen resistance. We investigated the biofilm formation capabilities of azole-resistant A. fumigatus and analysed the susceptibility of biofilms at various developmental stages to three antifungal agents.

METHODS: Biofilm formation of 19 clinical A. fumigatus strains (3 azole-susceptible and 16 azole-resistant strains) was determined by crystal violet staining and by an XTT assay over a period of 48 h. We measured antibiofilm activity of voriconazole, amphotericin B and olorofim. These agents were added before adhesion, after adhesion, after germination and to mature fungal biofilm. Antibiofilm activity was assessed in an XTT assay and in confocal laser scan microscopy. Additionally, a growth-kinetic assay with planktonic A. fumigatus was performed.

RESULTS: Each of the antifungal agents inhibited the metabolic activity of A. fumigatus biofilms when applied at early stages of biofilm formation. The mature biofilms were more resistant. Olorofim and voriconazole showed promising effects against A. fumigatus adhesion and germination, whereas the mature biofilm was not affected by treatment. In contrast, the biofilm of A. fumigatus showed amphotericin B susceptibility throughout the entire developmental process. The planktonic cells were susceptible to all three antifungal drug classes with an inhibition peak at 12 h after incubation.

CONCLUSIONS: This is the first known study to demonstrate the antibiofilm activity of olorofim, voriconazole and amphotericin B against azole-resistant A. fumigatus.}, } @article {pmid35288676, year = {2022}, author = {Guo, J and Zhang, Y and Cheng, H and Li, D and Wang, Z and Chen, C and Yu, Z and Deng, Q and Wen, Z}, title = {Inhibition of Staphylococcus aureus and biofilm formation by the anthelminthic drug, triclabendazole.}, journal = {The Journal of antibiotics}, volume = {75}, number = {5}, pages = {287-295}, pmid = {35288676}, issn = {1881-1469}, support = {82172283//National Natural Science Foundation of China (National Science Foundation of China)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Proteomics ; *Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus ; Triclabendazole ; }, abstract = {Triclabendazole (TBD) has been widely used in the treatment of helminthic infection. The anti-biofilm activity and antibacterial mechanism of TBD against Staphylococcus aureus were not known. Here, the anti-biofilm activity of TBD against clinical S. aureus isolates from China was systematically evaluated. Under TBD pressure, TBD-induced tolerant S. aureus with elevated TBD minimum inhibitory concentration (MIC) was selected in vitro and the genetic mutations between the parental isolates and TBD-induced tolerant derivatives were determined by whole-genome sequencing. TBD could significantly inhibit biofilm formation at sub-inhibitory concentration and disperse mature biofilm of clinical S. aureus isolates. In addition, TBD displayed bactericidal activity against the bacterial cells embedded in the biofilm and showed anti-persisters activity. Proteomic analysis showed that KEGG pathways of ABC transporters and beta-lactam resistance were significantly changed after TBD exposure. Moreover, SAUSA300_RS08395 (molecular chaperone DnaK), SAUSA300_RS11200 (sensor histidine kinase KdpD), SAUSA300_RS06325 (DNA translocase FtsK) were identified as candidate targets of TBD in S. aureus. Overexpression experiments further demonstrated that the elevated transcriptional level of DnaK resulted in S. aureus growth delay after exposure to a sub-MIC concentration of 1/2× MIC TBD. In conclusion, TBD exhibits antibacterial and anti-biofilm activity against S. aureus possibly by targeting the DnaK chaperone system.}, } @article {pmid35288606, year = {2022}, author = {Ajish, C and Yang, S and Kumar, SD and Kim, EY and Min, HJ and Lee, CW and Shin, SH and Shin, SY}, title = {A novel hybrid peptide composed of LfcinB6 and KR-12-a4 with enhanced antimicrobial, anti-inflammatory and anti-biofilm activities.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {4365}, pmid = {35288606}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/pharmacology ; Anti-Inflammatory Agents/chemistry/pharmacology ; *Antimicrobial Cationic Peptides/chemistry/pharmacology ; Biofilms ; Mice ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Sheep ; }, abstract = {Hybridizing two known antimicrobial peptides (AMPs) is a simple and effective strategy for designing antimicrobial agents with enhanced cell selectivity against bacterial cells. Here, we generated a hybrid peptide Lf-KR in which LfcinB6 and KR-12-a4 were linked with a Pro hinge to obtain a novel AMP with potent antimicrobial, anti-inflammatory, and anti-biofilm activities. Lf-KR exerted superior cell selectivity for bacterial cells over sheep red blood cells. Lf-KR showed broad-spectrum antimicrobial activities (MIC: 4-8 μM) against tested 12 bacterial strains and retained its antimicrobial activity in the presence of salts at physiological concentrations. Membrane depolarization and dye leakage assays showed that the enhanced antimicrobial activity of Lf-KR was due to increased permeabilization and depolarization of microbial membranes. Lf-KR significantly inhibited the expression and production of pro-inflammatory cytokines (nitric oxide and tumor necrosis factor-α) in LPS-stimulated mouse macrophage RAW264.7 cells. In addition, Lf-KR showed a powerful eradication effect on preformed multidrug-resistant Pseudomonas aeruginosa (MDRPA) biofilms. We confirmed using confocal laser scanning microscopy that a large portion of the preformed MDRPA biofilm structure was perturbed by the addition of Lf-KR. Collectively, our results suggest that Lf-KR can be an antimicrobial, anti-inflammatory, and anti-biofilm candidate as a pharmaceutical agent.}, } @article {pmid35288132, year = {2022}, author = {Xie, T and Xi, Y and Liu, Y and Liu, H and Su, Z and Huang, Y and Xu, W and Wang, D and Zhang, C and Li, X}, title = {Long-term effects of Cu(II) on denitrification in hydrogen-based membrane biofilm reactor: Performance, extracellular polymeric substances and microbial communities.}, journal = {The Science of the total environment}, volume = {830}, number = {}, pages = {154526}, doi = {10.1016/j.scitotenv.2022.154526}, pmid = {35288132}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Copper ; Denitrification ; *Extracellular Polymeric Substance Matrix ; Hydrogen ; *Microbiota ; Nitrates ; Nitrogen ; Organic Chemicals ; }, abstract = {Divalent copper (Cu(II)) frequently coexists with nitrate (NO3[-]) in industrial wastewater and the effect of Cu(II) on the autotrophic denitrification system using H2 as the electron donor remains unknown. In this study, the hydrogen-based membrane biofilm reactor (H2-MBfR) was operated continuously over 150 days to explore the effect of Cu(II) on the performance of autotrophic denitrification system and understand the key roles of EPS and microbial community. More than 95% of 20 mg-N/L NO3[-] was removed at 1-5 mg/L Cu(II), and the removal rate of NO3[-]-N was stabilized to 82% at 10 mg/L Cu(II) after a short period, while NH4[+] and NO2[-] in effluent were hardly detected, indicated that high concentration of Cu(II) did not permanently inhibit the denitrification performance in H2-MBfR. Colorimetric determination showed that Cu(II) stimulated the secretion of EPS, in which the protein (PN) content was much higher than polysaccharide (PS). The PN/PS ratios increased from 0.93 to 1.99, and the PN was more sensitive to copper invasion. The results of three-dimensional excitation-emission matrix illustrated that tryptophan was the main component of EPS chelating Cu(II) to reduce toxicity. The results of Fourier-transform infrared demonstrated that hydroxyl, carboxyl, and protein amide groups bound and reduced Cu(II). Furthermore, Cu(II) was effectively removed (>80%), and the results of distribution and morphology analysis of Cu(II) show that the electron-dense deposits of monovalent copper (Cu(I)) were found in EPS and biofilms and the reduction of Cu(II) to Cu(I) was an obvious self-defense reaction of biofilm to copper stress. The microbial richness and diversity decreased with the long-term exposure to Cu(II), while the relative abundance of denitrifiers Azospira and Dechloromonas increased. This study provides a scientific basis for the optimal design of treatment system for removal of nitrate and recovery of heavy metals simultaneously.}, } @article {pmid35287925, year = {2022}, author = {Raj, V and Kim, Y and Kim, YG and Lee, JH and Lee, J}, title = {Chitosan-gum arabic embedded alizarin nanocarriers inhibit biofilm formation of multispecies microorganisms.}, journal = {Carbohydrate polymers}, volume = {284}, number = {}, pages = {118959}, doi = {10.1016/j.carbpol.2021.118959}, pmid = {35287925}, issn = {1879-1344}, mesh = {Anthraquinones ; Biofilms ; Candida albicans ; *Chitosan/pharmacology ; Gum Arabic/pharmacology ; }, abstract = {Biofilm formation by microorganisms is a serious clinical problem that leads to drug failure. Nanocarriers (NCs) have shown good potential for controlling drug-resistant biofilms, although the effective penetration and retention of NCs in biofilms is still a big task. The issue was overcome by selecting alizarin as a natural antibiofilm agent, but its low water solubility restricts its further use. Thus, in present study, chitosan-gum arabic-coated liposomes-alizarin nanocarriers (CGL-Alz NCs) were synthesized using an ionotropic gelation method to improve drug release and penetration of alizarin inside biofilm cells. CGL-Alz NCs acted against biofilms caused by Candida albicans or Staphylococcus aureus and improved penetration of alizarin inside biofilms exerting long-term antibiofilm effects caused by sustained release of alizarin from NCs. Furthermore, significant biofilm and hyphae reduction was observed at a 5 μg/mL concentration of NCs. This research work opens a new avenue of an innovative strategy to treat biofilm-associated multispecies infections.}, } @article {pmid35287816, year = {2022}, author = {Nahar, S and Jeong, HL and Cho, AJ and Park, JH and Han, S and Kim, Y and Park, SH and Ha, SD}, title = {Efficacy of ficin and peroxyacetic acid against Salmonella enterica serovar Thompson biofilm on plastic, eggshell, and chicken skin.}, journal = {Food microbiology}, volume = {104}, number = {}, pages = {103997}, doi = {10.1016/j.fm.2022.103997}, pmid = {35287816}, issn = {1095-9998}, mesh = {Animals ; Biofilms ; Chickens ; Egg Shell ; Ficain/pharmacology ; *Peracetic Acid/pharmacology ; Plastics/pharmacology ; Salmonella ; *Salmonella enterica ; Serogroup ; }, abstract = {Salmonella is the leading cause of zoonotic foodborne illnesses worldwide and a prevalent threat to the poultry industry. For controlling contamination, the use of chemical sanitizers in combination with biological compounds (e.g., enzymes) offers a solution to reduce the chemical residues. The current study investigated the biofilm reduction effects of a food-grade enzyme-ficin-and a common sanitizer-peroxyacetic acid (PAA)-against an emerging pathogen, Salmonella enterica ser. Thompson, on plastic, eggshell, and chicken skin surfaces. Results showed that PAA could kill S. Thompson, but ficin cannot. Maximum biofilm reduction was 3.7 log CFU/cm[2] from plastic after individual treatment with PAA. However, sequential treatment of ficin and PAA led to biofilm reductions of 3.2, 5.0, and 6.5 log CFU/cm[2] from chicken skin, eggshell, and plastic, respectively. Fourier-transform infrared spectroscopy and microscopic analysis confirmed that ficin increased PAA action, causing biofilm matrix destruction. Moreover, the quality of the food surfaces was only altered by 12.5 U/mL ficin and was not altered by PAA. This combined use of enzyme and sanitizer solved major safety issues and proved promising against S. Thompson-associated contaminations in poultry and poultry processing lines.}, } @article {pmid35286605, year = {2022}, author = {Lee, KT and Lee, DG and Choi, JW and Park, JH and Park, KD and Lee, JS and Bahn, YS}, title = {The novel antifungal agent AB-22 displays in vitro activity against hyphal growth and biofilm formation in Candida albicans and potency for treating systemic candidiasis.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {60}, number = {4}, pages = {438-443}, pmid = {35286605}, issn = {1976-3794}, mesh = {Animals ; Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; *Candida albicans ; *Candidiasis/drug therapy/microbiology ; Hyphae ; Mice ; }, abstract = {Systemic candidiasis, which is mainly caused by Candida albicans, is a serious acute fungal infection in the clinical setting. In a previous study, we reported that compound 22h (designated as AB-22 in this study), a vinyl sulfate compound, is a fast-acting fungicidal agent against a broad spectrum of fungal pathogens. In this study, we aimed to further analyze the in vitro and in vivo efficacy of AB-22 against filamentation, biofilm formation, and virulence of C. albicans. Under in vitro hyphal growth-inducing condition, AB-22 effectively inhibited germ tube formation and hyphal growth, which are required for the initiation of biofilm formation. Indeed, AB-22 significantly suppressed C. albicans biofilm formation in a dose-dependent manner. Moreover, AB-22 treatment inhibited the normal induction of ALS3, HWP1, and ECE1, which are all required for hyphal transition in C. albicans. Furthermore, AB-22 treatment increased the survival of mice systemically infected with C. albicans. In conclusion, in addition to its fungicidal activity, AB-22 inhibits filamentation and biofilm formation in C. albicans, which could collectively contribute to its potent in vivo efficacy against systemic candidiasis.}, } @article {pmid35285005, year = {2022}, author = {Palanichamy, E and Repally, A and Jha, N and Venkatesan, A}, title = {Haloalkaline Lipase from Bacillus flexus PU2 Efficiently Inhibits Biofilm Formation of Aquatic Pathogen Vibrio parahaemolyticus.}, journal = {Probiotics and antimicrobial proteins}, volume = {14}, number = {4}, pages = {664-674}, pmid = {35285005}, issn = {1867-1314}, mesh = {Bacillus ; Biofilms ; Escherichia coli/metabolism ; Lipase/genetics/metabolism ; *Vibrio parahaemolyticus ; }, abstract = {A gene encoding lipase enzyme from Bacillus flexus PU2 was cloned and expressed in E. coli BL21 (DE3) pLysS and purified protein having the molecular weight of 34 kDa. This lipase was found to be alkaline (pH 9) and slightly thermophilic. This lipase was observed to retain its activity in the presence of methanol, ethanol, DMSO, and acetone. Ferrous sulfate, copper sulfate, and manganese sulfate highly enhanced the lipase activity. All the surfactants and detergents were found to inhibit the enzyme activity, whereas the bleaching agent hydrogen peroxide was found to increase the activity. This lipase was observed as a metalloenzyme, and its activity was highly inhibited by EDTA. Also, it is moderately halophilic and can retain the activity between 0.2 and 0.8 M NaCl. Biofilm inhibitory potential of purified lipase was tested against pathogenic Vibrio parahaemolyticus, and the minimal inhibitory concentration observed was 350 U. Different concentration of this enzyme significantly changed the morphology and biofilm density of V. parahaemolyticus and was evinced by SEM and CLSM imaging. The transcriptome levels of genes responsible for biofilm formation, motility, and virulence such as, motX, fliG, and trh were significantly downregulated with lipase treatment.}, } @article {pmid35284607, year = {2022}, author = {Berlec, A and Janež, N and Sterniša, M and Klančnik, A and Sabotič, J}, title = {Listeria innocua Biofilm Assay Using NanoLuc Luciferase.}, journal = {Bio-protocol}, volume = {12}, number = {3}, pages = {e4308}, pmid = {35284607}, issn = {2331-8325}, abstract = {Biofilms serve as a bacterial survival strategy, allowing bacteria to persist under adverse environmental conditions. The non-pathogenic Listeria innocua is used as a surrogate organism for the foodborne pathogen Listeria monocytogenes, because they share genetic and physiological similarities and can be used in a Biosafety Level 1 laboratory. Several methods are used to evaluate biofilms, including different approaches to determine biofilm biomass or culturability, viability, metabolic activity, or other microbial community properties. Routinely used methods for biofilm assay include the classical culture-based plate counting method, biomass staining methods (e.g., crystal violet and safranin red), DNA staining methods (e.g., Syto 9), methods that use metabolic substrates to detect live bacteria (e.g., tetrazolium salts or resazurin), and PCR-based methods to quantify bacterial DNA. The NanoLuc (Nluc) luciferase biofilm assay is a viable alternative or complement to existing methods. Functional Nluc was expressed in L. innocua using the nisin-inducible expression system and bacterial detection was performed using furimazine as substrate. Concentration dependent bioluminescence signals were obtained over a concentration range greater than three log units. The Nluc bioluminescence method allows absolute quantification of bacterial cells, has high sensitivity, broad range, good day-to-day repeatability, and good precision with acceptable accuracy. The advantages of Nluc bioluminescence also include direct detection, absolute cell quantification, and rapid execution. Graphic abstract: Engineering Listeria innocua to express NanoLuc and its application in bioluminescence assay.}, } @article {pmid35284338, year = {2022}, author = {Pedonese, F and Longo, E and Torracca, B and Najar, B and Fratini, F and Nuvoloni, R}, title = {Antimicrobial and anti-biofilm activity of manuka essential oil against Listeria monocytogenes and Staphylococcus aureus of food origin.}, journal = {Italian journal of food safety}, volume = {11}, number = {1}, pages = {10039}, pmid = {35284338}, issn = {2239-7132}, abstract = {The activity of manuka (Leptospermum scoparium) essential oil (EO) on biofilms of foodborne Listeria monocytogenes and Staphylococcus aureus has been studied. Seven strains of L. monocytogenes and 7 of S. aureus (5 methicillin-resistant) were tested. EO minimal inhibitory concentration (MIC), EO minimal bactericidal concentration (MBC) and biofilm production quantification were determined for each strain by microtiter methods. Moreover, EO Minimum Biofilm Inhibitory Concentration (MBIC) and Minimum Biofilm Eradicating Concentration (MBEC) were determined on 2 L. monocytogenes and 3 S. aureus that showed the best biofilm production. Finally, on 4 strains out of 5 (2 L. monocytogenes and 2 S. aureus) EO Biofilm Reduction Percentage (BRP) vs. untreated controls was assessed after a treatment with EO subinhibitory concentrations. The chemical composition of manuka essential oil was determined by Gas Chromatography- Electron Impact Mass Spectrometry (GCEIMS). The manuka EO demonstrated good antimicrobial activity: L. monocytogenes MIC and MBC were 0.466 mg/ml and 0.933 mg/ml, respectively, whereas S. aureus MIC and MBC were 0.233 mg/ml and 0.466 mg/ml, respectively. Furthermore, L. monocytogenes showed a MBIC of 0.933 mg/ml and a MBEC in the range of 0.933-1.865 mg/ml, whereas S. aureus had a MBIC in the range of 7.461-14.922 mg/ml and a MBEC of 14.922 mg/ml. L. monocytogenes revealed no significant BRP after the treatment with manuka EO, whereas S. aureus showed a BRP higher than 50% with MIC/2 and MIC/4 EO concentrations. These results provide information for feasible manuka EO applications in food production systems.}, } @article {pmid35283841, year = {2022}, author = {Jiang, X and Jiang, C and Yu, T and Jiang, X and Ren, S and Kang, R and Qiu, S}, title = {Benzalkonium Chloride Adaptation Increases Expression of the Agr System, Biofilm Formation, and Virulence in Listeria monocytogenes.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {856274}, pmid = {35283841}, issn = {1664-302X}, abstract = {Benzalkonium chloride (BC) is widely used for disinfection in food industry. However, prolonged exposure to BC may lead to the emergence of BC adapted strains of Listeria monocytogenes, an important foodborne pathogen. Until now, two communication systems, the LuxS/AI-2 system and the Agr system, have been identified in L. monocytogenes. This study aimed to investigate the role of communication systems in BC adaptation and the effect of BC adaptation on two communication systems and the communication-controlled behaviors in L. monocytogenes. Results demonstrated that the Agr system rather than the LuxS system plays an important role in BC adaptation of L. monocytogenes. Neither luxS expression nor AI-2 production was affected by BC adaptation. On the other hand, the expression of the agr operon and the activity of the agr promoter were significantly increased after BC adaptation. BC adaptation enhanced biofilm formation of L. monocytogenes. However, swarming motility was reduced by BC adaptation. Data from qRT-PCR showed that flagella-mediated motility-related genes (flaA, motA, and motB) were downregulated in BC adapted strains. BC adaptation increased the ability of L. monocytogenes to adhere to and invade Caco-2 cells but did not affect the hemolytic activity. Compared with the wild-type strains, the expression levels of virulence genes prfA, plcA, mpl, actA, and plcB increased more than 2-fold in BC adapted strains; however, lower than 2-fold changes in the expression of hemolysis-associated gene hly were observed. Our study suggests that BC adaptation could increase the expression of the Agr system and enhance biofilm formation, invasion, and virulence of L. monocytogenes, which brings about threats to food safety and public health. Therefore, effective measures should be taken to avoid the emergence of BC adapted strains of L. monocytogenes.}, } @article {pmid35283053, year = {2022}, author = {Noly, PE and Pagani, FD}, title = {Bacteriophage therapy and the biofilm: An old solution for a persistent and desperate problem?.}, journal = {The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation}, volume = {41}, number = {5}, pages = {556-557}, doi = {10.1016/j.healun.2022.02.007}, pmid = {35283053}, issn = {1557-3117}, mesh = {Biofilms ; Humans ; *Phage Therapy ; }, } @article {pmid35281594, year = {2022}, author = {Yang, H and Xu, F and Zheng, X and Yang, S and Ren, Z and Yang, J}, title = {Human Umbilical Cord Mesenchymal Stem Cells Prevent Bacterial Biofilm Formation.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {1530525}, pmid = {35281594}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/metabolism ; Biofilms ; Humans ; Infant, Newborn ; Infant, Premature ; *Mesenchymal Stem Cells/metabolism ; *Umbilical Cord ; }, abstract = {Biofilm formation is easily found in patients suffered from ventilator-associated pneumonia (VAP) in neonatal intensive care unit (NICU) and makes the VAP infections not only harder to be treated but easier to relapse. In order to find some novel ways to inhibit biofilm formation, this study describe a previously unrecognized role for the human umbilical cord mesenchymal stem cells (hUCMSCs). In addition to multiple differentiation, hUCMSCs have the ability to prevent the biofilms formation in vitro by secreting antibacterial peptides (LL-37 and hBD-2). This occurred while P. aeruginosa PA27853 and hUCMSCs were cocultured, and the filtrated medium, which was the supernatant containing antibacterial peptides (5.9 ng/ml of LL-37, 1.77 ng/ml of hBD-2), and inhibited the growth of the bacterial biofilm on the surface of tracheal tube (2.5#, for preterm infant). Using microarrays, we were able to demonstrate that the antibacterial peptides from hUCMSC affected biofilm formation by downregulating the gene-encoded polysaccharide biosynthesis protein. In addition, in order to find out the most suitable concentration of hUCMSCs, P. aeruginosa was cocultured with eight-level concentrations of hUCMSCs, and we found that the concentration of LL-37 was positively correlated with the concentration of hUCMSCs. Meanwhile, the concentration of LL-37 became stable while the hUCMSC concentration reaches higher than 5 × 10[6] cells/ml. But the concentration of hBD-2 had no significant correlation with hUCMSCs. The collection of these stem cells is not only limited by ethics but also reduces host rejection. This makes it possible to use autologous hUCMSCs to treat neonatal VAP.}, } @article {pmid35281447, year = {2022}, author = {Hawas, S and Verderosa, AD and Totsika, M}, title = {Combination Therapies for Biofilm Inhibition and Eradication: A Comparative Review of Laboratory and Preclinical Studies.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {850030}, pmid = {35281447}, issn = {2235-2988}, mesh = {*Anti-Bacterial Agents/pharmacology/therapeutic use ; *Biofilms ; Microbial Sensitivity Tests ; Quorum Sensing ; }, abstract = {Microbial biofilms are becoming increasingly difficult to treat in the medical setting due to their intrinsic resistance to antibiotics. To combat this, several biofilm dispersal agents are currently being developed as treatments for biofilm infections. Combining biofilm dispersal agents with antibiotics is emerging as a promising strategy to simultaneously disperse and eradicate biofilms or, in some cases, even inhibit biofilm formation. Here we review studies that have investigated the anti-biofilm activity of some well-studied biofilm dispersal agents (e.g., quorum sensing inhibitors, nitric oxide/nitroxides, antimicrobial peptides/amino acids) in combination with antibiotics from various classes. This review aims to directly compare the efficacy of different combination strategies against microbial biofilms and highlight synergistic treatments that warrant further investigation. By comparing across studies that use different measures of efficacy, we can conclude that treating biofilms in vitro and, in some limited cases in vivo, with a combination of an anti-biofilm agent and an antibiotic, appears overall more effective than treating with either compound alone. The review identifies the most promising combination therapies currently under development as biofilm inhibition and eradication therapies.}, } @article {pmid35281445, year = {2022}, author = {Pan, P and Wang, X and Chen, Y and Chen, Q and Yang, Y and Wei, C and Cheng, T and Wan, H and Yu, D}, title = {Effect of Hcp Iron Ion Regulation on the Interaction Between Acinetobacter baumannii With Human Pulmonary Alveolar Epithelial Cells and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {761604}, pmid = {35281445}, issn = {2235-2988}, mesh = {*Acinetobacter baumannii/pathogenicity ; *Alveolar Epithelial Cells/microbiology ; Bacterial Adhesion ; *Bacterial Proteins/metabolism ; Biofilms ; *Hemolysin Proteins/metabolism ; Humans ; Ions/metabolism ; Iron/metabolism ; }, abstract = {Acinetobacter baumannii is a type of bacterial nosocomial infection with severe drug resistance. Hemolysin co-regulated protein (Hcp) is a marker of activated type VI secretion system (T6SS), a key secretory system that promotes Gram-negative bacteria colonization, adhesion, and invasion of host cells. Hcp is also regulated by iron ions (Fe). In this study, an ATCC17978 hcp deletion strain (ATCC17978Δhcp), an hcp complement strain (ATCC17978Δhcp[+]), and an A. baumannii-green fluorescent protein (GFP) strain were constructed and used to investigate the role of hcp in bacterial adhesion to cells (human pulmonary alveolar epithelial cells (HPAEpiC)) and biofilm formation. Our results indicate that the inhibitory concentrations of the three A. baumannii strains (ATCC17978 wild type, ATCC17978Δhcp, and ATCC17978Δhcp[+]) were drug-sensitive strains. A. baumannii hcp gene and iron ions might be involved in promoting the formation of a biofilm and host-bacteria interaction. Iron ions affected the ability of A. baumannii to adhere to cells, as there was no significant difference in the bacterial numbers when assessing the adhesion of the three strains to HPAEpiC in the presence of iron ion concentrations of 0 μM (F = 3.1800, p = 0.1144), 25 μM (F = 2.067, p = 0.2075), 100 μM (F = 30.52, p = 0.0007), and 400 μM (F = 17.57, p = 0.0031). The three strains showed significant differences in their ability to adhere to HPAEpiC. The numbers of bacteria adhesion to HPAEpiC were ATCC17978Δhcp>ATCC17978Δhcp[+]>ATCC17978 in descending order. Hcp gene was positively regulated by iron ions in the bacteria-cells' co-culture. It is speculated that the effect of iron ions on the interaction between A. baumannii and HPAEpiC might be related to the transport function of hcp and bacterial immune escape mechanisms.}, } @article {pmid35280972, year = {2022}, author = {Subbiahdoss, G and Osmen, S and Reimhult, E}, title = {Cellulosic biofilm formation of Komagataeibacter in kombucha at oil-water interfaces.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100071}, pmid = {35280972}, issn = {2590-2075}, abstract = {Bacteria forming biofilms at oil-water interfaces have diverse metabolism, they use hydrocarbons as a carbon and energy source. Kombucha is a fermented drink obtained from a complex symbiotic culture of bacteria and yeast, where acetic acid bacteria present in kombucha use sugars as a carbon source to produce cellulosic biofilms. We hypothesize that Komagataeibacteraceae in kombucha can adsorb to and use hydrocarbons as the sole energy source to produce cellulosic biofilms. Hence we characterized a kombucha culture, studied bacterial adsorption and cellulosic biofilm formation of kombucha at the n-decane or mineral oil-kombucha suspension interface. The cellulosic biofilms were imaged using fluorescence microscopy and cryo-scanning electron microscopy, and their time-dependent rheology was measured. Komagataeibacter, the dominant bacterial genus in the kombucha culture, produced cellulosic biofilms with reduced cellulose biomass yield at the oil-kombucha suspension interfaces compared to at the air-kombucha suspension interface. The presence of biosurfactants in the supernatant secreted by the kombucha microbes led to a larger and faster decrease in the interfacial tension on both oil types, leading to the formation of stable and elastic biofilm membranes. The difference in interfacial tension reduction was insignificant already after 2 h of biofilm formation at the mineral oil-kombucha suspension interface compared to kombucha microbes resuspended without biosurfactants but persisted for longer than 24 h in contact with n-decane. We also demonstrate that Komagataeibacter in kombucha can produce elastic cellulosic biofilms using hydrocarbons from the oil interface as the sole source of carbon and energy. Thus Komagataeibacter and kombucha shows the potential of this system for producing valued bacterial cellulose through remediation of hydrocarbon waste.}, } @article {pmid35280554, year = {2022}, author = {Khalid, SJ and Ain, Q and Khan, SJ and Jalil, A and Siddiqui, MF and Ahmad, T and Badshah, M and Adnan, F}, title = {Targeting Acyl Homoserine Lactones (AHLs) by the quorum quenching bacterial strains to control biofilm formation in Pseudomonas aeruginosa.}, journal = {Saudi journal of biological sciences}, volume = {29}, number = {3}, pages = {1673-1682}, pmid = {35280554}, issn = {1319-562X}, abstract = {Navigating novel biological strategies to mitigate bacterial biofilms have great worth to combat bacterial infections. Bacterial infections caused by the biofilm forming bacteria are 1000 times more resistant to antibiotics than the planktonic bacteria. Among the known bacterial infections, more than 70% involve biofilms which severely complicates treatment options. Biofilm formation is mainly regulated by the Quorum sensing (QS) mechanism. Interference with the QS system by the quorum quenching (QQ) enzyme is a potent strategy to mitigate biofilm. In this study, bacterial strains with QQ activity were identified and their anti-biofilm potential was investigated against the Multidrug Resistant (MDR) Pseudomonas aeruginosa. A Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136-based bioassays were used to confirm the degradation of different Acyl Homoserine Lactones (AHLs) by QQ isolates. The 16S rRNA gene sequencing of the isolated strains identified them as Bacillus cereus strain QSP03, B. subtilis strain QSP10, Pseudomonas putida strain QQ3 and P. aeruginosa strain QSP01. Biofilm mitigation potential of QQ isolates was tested against MDR P. aeruginosa and the results suggested that 50% biofilm reduction was observed by QQ3 and QSP01 strains, and around 60% reduction by QSP10 and QSP03 bacterial isolates. The presence of AHL degrading enzymes, lactonases and acylases, was confirmed by PCR based screening and sequencing of the already annotated genes aiiA, pvdQ and quiP. Altogether, these results exhibit that QQ bacterial strains or their products could be useful to control biofilm formation in P.aeruginosa.}, } @article {pmid35280335, year = {2022}, author = {Zhao, D and Zhang, R and Liu, X and Li, X and Xu, M and Huang, X and Xiao, X}, title = {Screening of Chitosan Derivatives-Carbon Dots Based on Antibacterial Activity and Application in Anti-Staphylococcus aureus Biofilm.}, journal = {International journal of nanomedicine}, volume = {17}, number = {}, pages = {937-952}, pmid = {35280335}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; Carbon/chemistry/pharmacology ; *Chitosan/chemistry/pharmacology ; Humans ; *Staphylococcus aureus ; }, abstract = {INTRODUCTION: Pathogenic bacteria, especially the ones with highly organized, systematic aggregating bacteria biofilm, would cause great harm to human health. The development of highly efficient antibacterial and antibiofilm functional fluorescent nanomaterial would be of great significance.

METHODS: This paper reports the preparation of a series of antibacterial functional carbon dots (CDs) with chitosan (CS) and its derivatives as raw materials through one-step route, and the impact of various experiment parameters upon the optical properties and the antibacterial abilities have been explored, including the structures of the raw materials, excipients, and solvents.

RESULTS: The CDs prepared by quaternary ammonium salt of chitosan (QCS) and ethylenediamine (EDA) exhibit multiple antibacterial effects through membrane breaking, DNA and protein destroying, and the production of singlet oxygen. The CDs showed excellent broad-spectrum inhibitory activity against a variety of bacteria (Gram-positive and negative bacteria), in particular, to the biofilm of Staphylococcus aureus with minimum inhibitory concentration at 10 µg/mL, showing great potential in killing bacteria and biofilms. The biocompatibility experiments proved that QCS-EDA-CDs are non-toxic to human normal hepatocytes and have low haemolytic effect. Furthermore, the prepared QCS-EDA-CDs have been successfully used in bacterial and biofilm imaging thanks to their excellent optical properties.

CONCLUSION: This paper explored the preparation and application of functional CDs, which can be used as the visual probe and therapeutic agents in the treatment of infections caused by bacteria and biofilm.}, } @article {pmid35279139, year = {2022}, author = {Vajrabhaya, LO and Korsuwannawong, S and Ruangsawasdi, N and Phruksaniyom, C and Srichan, R}, title = {The efficiency of natural wound healing and bacterial biofilm inhibition of Aloe vera and Sodium Chloride toothpaste preparation.}, journal = {BMC complementary medicine and therapies}, volume = {22}, number = {1}, pages = {66}, pmid = {35279139}, issn = {2662-7671}, mesh = {*Aloe ; Biofilms ; Humans ; Sodium Chloride/pharmacology ; *Toothpastes/pharmacology ; Wound Healing ; }, abstract = {BACKGROUND: Prevention is a preliminary focus of periodontitis treatment. Rather than giving complicated treatment to a periodontitis patient, a variety of toothpastes have been suggested to prevent periodontal disease progression. Herbal toothpastes containing natural plant components for maintaining or increasing healing might be a treatment modality for improving oral hygiene. Aloe vera is a medicinal plant with active ingredients that have antioxidant and anti-inflammatory effects. Additionally, increased sodium in the environment inhibits microorganism growth. A toothpaste containing salt and aloe vera may be an option to provide good oral hygiene.

AIM: To assess the in vitro cell migration of human gingival fibroblasts and antimicrobial effects of an herbal toothpaste containing A. vera and Sodium chloride.

METHODS: The cytotoxicity of 0.02% or 0.2% toothpaste solution on human gingival fibroblast cell line was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The cell migration after treatment with 0.2% (v/v) toothpaste was determined using a Boyden Chamber assay. The effect of the toothpaste on inhibiting Porphylomonas gingivalis planktonic and biofilm growth was compared with Chlohexidine (CHX) using a Disk Diffusion and Biofilm susceptibility test, respectively. The results of the cytotoxicity assay, inhibition zone and percentage of live cells in the biofilm were statistically analyzed with One-way analysis of variance. Cell migration and biofilm inhibition were evaluated using the independent sample t-test and multiple t-test, respectively (p = 0.05).

RESULTS: Neither test concentration of the toothpaste solution was toxic to the target cells. The 0.2% concentration was selected for the cell migration experiment. The herbal toothpaste formulation significantly increased cell migration compared with the control group (culture medium) (p = .02) The antimicrobial effect of this formulation on the P. gingivalis planktonic form was lower compared with 0.12% CHX (positive control group), however, it demonstrated greater P. gingivalis biofilm formation inhibition compared with the 0.12% CHX group.

CONCLUSIONS: The alternative use of an herbal toothpaste instead of a non-herbal toothpaste formulation should be considered for promoting oral health care. However, further clinical studies are necessary before it can be considered for patient use.}, } @article {pmid35278448, year = {2022}, author = {Khan, NA and Khan, AH and Ahmed, S and Farooqi, IH and Alam, SS and Ali, I and Bokhari, A and Mubashir, M}, title = {Efficient removal of ibuprofen and ofloxacin pharmaceuticals using biofilm reactors for hospital wastewater treatment.}, journal = {Chemosphere}, volume = {298}, number = {}, pages = {134243}, doi = {10.1016/j.chemosphere.2022.134243}, pmid = {35278448}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Hospitals ; Humans ; Ibuprofen ; Ofloxacin ; Pharmaceutical Preparations ; Waste Disposal, Fluid/methods ; Wastewater/chemistry ; *Water Pollutants, Chemical/analysis ; *Water Purification ; }, abstract = {Hospital wastewater is harmful to the environment and human health due to its complex chemical composition and high potency towards becoming a source of disease outbreaks. Due to these complexities, its treatment is neither efficient nor cost-effective. It is a challenging issue that requires immediate attention. This effort focuses on the treatment of hospital wastewater (HWW) by removing two selected drugs, namely ibuprofen (IBU) and ofloxacin (OFX) using individual biological treatment methods, such as moving bed biofilm reactors (MBBR) and physicochemical treatment, such as ozonation and peroxane process. The both methods are compared to find the best method overall based on effectiveness and removal efficiency. The optimal removal for ozone dosing range was nitrate (9.00% and 62.00%), biological oxygen demand (BOD) (92.00% and 64.00%), and chemical oxygen demand (COD) (96.00% and 92.00%) that required at least 10 min to reach considerable degradation. The MBBR process assured a better performance for ibuprofen removal, overall. The IBU and OFX removal was found to be 14.32-96.00% at a higher COD value and 11.33-94.00% at a lower COD value due to its biodegradation. This work strives to pave the way forward to build an HWW treatment technology using integrated MBBR processes for better efficiency and cost-effectiveness.}, } @article {pmid35276175, year = {2022}, author = {de Bruin, S and Vasquez-Cardenas, D and Sarbu, SM and Meysman, FJR and Sousa, DZ and van Loosdrecht, MCM and Lin, Y}, title = {Sulfated glycosaminoglycan-like polymers are present in an acidophilic biofilm from a sulfidic cave.}, journal = {The Science of the total environment}, volume = {829}, number = {}, pages = {154472}, doi = {10.1016/j.scitotenv.2022.154472}, pmid = {35276175}, issn = {1879-1026}, mesh = {*Biofilms ; Glycosaminoglycans ; *Polymers/chemistry ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Sulfated glycosaminoglycans (sGAG) are negatively charged extracellular polymeric substances that occur in biofilms from various environments. Yet, it remains unclear whether these polymers are acquired from the external environment or produced by microbes in the biofilm. To resolve this, we analyzed the presence of sGAGs in samples of an acidophilic biofilm collected from Sulfur Cave in Puturosu Mountain (Romania), an environment that is largely inaccessible to contamination. A maximum of 55.16 ± 2.06 μg sGAG-like polymers were recovered per mg of EPS. Enzymatic treatment with chondroitinase ABC resulted in a decrease of the mass of these polymers, suggesting the structure of the recovered sGAG is similar to chondroitin. Subsequent FT-IR analysis of these polymers revealed absorbance bands at 1230 cm[-1], 1167 cm[-1] and 900 cm[-1], indicating a possible presence of polysaccharides and sulfate. Analysis of genomic sequences closely related to those predominant in the acidophilic biofilm, contained genes coding for sulfotransferase (an enzyme needed for the production of sGAG), which supports the hypothesis of microbial synthesis of sGAGs within the biofilm.}, } @article {pmid35276160, year = {2022}, author = {Zhang, Z and Ni, BJ and Zhang, L and Liu, Z and Fu, W and Dai, X and Sun, J}, title = {Medium-chain fatty acids production from carbohydrates-rich wastewater through two-stage yeast biofilm processes without external electron donor addition: Biofilm development and pH impact.}, journal = {The Science of the total environment}, volume = {828}, number = {}, pages = {154428}, doi = {10.1016/j.scitotenv.2022.154428}, pmid = {35276160}, issn = {1879-1026}, mesh = {Biofilms ; Carbohydrates ; Carbon ; Electrons ; Ethanol ; Fatty Acids ; Fermentation ; Hydrogen-Ion Concentration ; *Saccharomyces cerevisiae ; *Wastewater ; }, abstract = {The production of medium-chain fatty acids (MCFAs) is considered promising for carbon resource recovery from waste streams. However, a large quantity of external electron donors are often required, causing great cost and environmental impact. Therefore, in this study, a two-stage technology was developed to produce MCFAs from carbohydrate-rich wastewater without external electron donor addition, with the biofilm development and pH impact being explored. Stage I aimed at converting organics into ethanol and a yeast biofilm reactor is innovatively applied. The results showed that the yeast biofilm could quickly form on carriers with steady-state thickness reaching 50-200 μm. However, the attachment of yeast biofilm was weak at the initial stage so that the violent turbulence should be avoided during operation. The polyurethane foam was the most suitable for yeast biofilm development among the tested carriers, as evidenced by the highest ethanol production, accounting for 74.2% of soluble organics. The Nakaseomyces was the main fungal genus in the steady-state biofilm, while lactic acid bacteria were also developed, resulting in lactate and acetate production. In Stage II, the yeast biofilm reactor effluent was applied for MCFA production at different pH (5-8). However, the MCFA production selectivity was significantly affected by pH, with 65.2% at pH of 5 but decreasing substantially to 3.0% at pH of 8. Both the microbial and electron transfer efficiency analysis suggested that mildly acidic pH can promote the electron transfer from ethanol toward the chain elongation process instead of its excessive oxidation. Thus, if conditions of online extraction or microbial tolerance permit, a lower pH should be recommended for Stage II in the developed technology as well as other ethanol-based MCFA production process. This is a conceptual study that eliminated external electron donor addition in MCFAs production and provide a sustainable and reliable way in carbon resources recovery.}, } @article {pmid35274866, year = {2022}, author = {Aitsev, AV and Vasilyev, AO and Shiryaev, AA and Kim, YA and Arefieva, OA and Govorov, AV and Pushkar, DY}, title = {[Biofilm control in urological practice].}, journal = {Urologiia (Moscow, Russia : 1999)}, volume = {}, number = {1}, pages = {81-88}, pmid = {35274866}, issn = {1728-2985}, mesh = {Biofilms ; *Cross Infection/drug therapy ; Humans ; Urinary Catheterization ; Urinary Catheters ; *Urinary Tract Infections/microbiology ; }, abstract = {Urinary tract infections (UTIs) have long been among the most common diseases. In the structure of the general infectious morbidity, UTIs rank second after acute respiratory viral infection. Every year, researchers note an increasing number of mutations in the genomes of bacteria that cause infectious diseases, which leads to the formation of more and more aggressive forms of pathogens. Patients with infectious diseases of the urinary system have the highest risk of biofilm formation, the frequency of which is directly proportional to the length of time the urethral catheter is located and accounts for more than half of all nosocomial infections. The presence of resistant strains of pathogenic bacteria and the development of bacterial biofilms are major problems in the treatment of urinary tract infections. The increasing number of nosocomial bacterial strains in the hospital increases the postoperative bed-day, the frequency of readmission and the number of antibacterial drugs used. In light of increasing antibacterial resistance, the use of medical resources is dramatically increasing, which ultimately leads to an increase in the cost of treatment. Along with this, the selection of resistant strains brings to the fore both the rational use of antibacterial drugs and the search for alternative methods of therapy. This review of publications on the problem of bacterial biofilm formation in urological practice demonstrates updated information on the role of enzymes, probiotics, and bacteriophages in preventing biofilm formation on various medical biomaterials, such as urethral catheters.}, } @article {pmid35274289, year = {2022}, author = {Zhang, Y and Silva, DM and Young, P and Traini, D and Li, M and Ong, HX and Cheng, S}, title = {Understanding the effects of aerodynamic and hydrodynamic shear forces on Pseudomonas aeruginosa biofilm growth.}, journal = {Biotechnology and bioengineering}, volume = {119}, number = {6}, pages = {1483-1497}, pmid = {35274289}, issn = {1097-0290}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Hydrodynamics ; *Pseudomonas aeruginosa ; Stress, Mechanical ; }, abstract = {Biofilms are communities of bacterial cells encased in a self-produced polymeric matrix and exhibit high tolerance towards environmental stress. Despite the plethora of research on biofilms, most biofilm models are produced using mono-interface culture in static flow conditions, and knowledge of the effects of interfaces and mechanical forces on biofilm development remains fragmentary. This study elucidated the effects of air-liquid (ALI) or liquid-liquid (LLI) interfaces and mechanical shear forces induced by airflow and hydrodynamic flow on biofilm growing using a custom-designed dual-channel microfluidic platform. Results from this study showed that comparing biofilms developed under continuous nutrient supply and shear stresses free condition to those developed with limited nutrient supply, ALI biofilms were four times thicker, 60% less permeable, and 100 times more resistant to antibiotics, while LLI biofilms were two times thicker, 20% less permeable, and 100 times more resistant to antibiotics. Subjecting the biofilms to mechanical shear stresses affected the biofilm structure across the biofilm thickness significantly, resulting in generally thinner and denser biofilm compared to their controlled biofilm cultured in the absence of shear stresses, and the ALI and LLI biofilm's morphology was vastly different. Biofilms developed under hydrodynamic shear stress also showed increased antibiotic resistance. These findings highlight the importance of investigating biofilm growth and its mechanisms in realistic environmental conditions and demonstrate a feasible approach to undertake this study using a novel platform.}, } @article {pmid35273262, year = {2022}, author = {Tarawneh, O and Abu Mahfouz, H and Hamadneh, L and Deeb, AA and Al-Sheikh, I and Alwahsh, W and Fadhil Abed, A}, title = {Assessment of persistent antimicrobial and anti-biofilm activity of p-HEMA hydrogel loaded with rifampicin and cefixime.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {3900}, pmid = {35273262}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cefixime/pharmacology ; Female ; HEK293 Cells ; Humans ; Hydrogels/pharmacology ; Male ; Methacrylates ; *Rifampin/pharmacology ; *Urinary Tract Infections/drug therapy ; }, abstract = {Catheter-associated urinary tract infections (CAUTIs) are nosocomial infections causing more than one million hospital cases annually. The progress of CAUTIs leads to severe health complications. Infections result in blockage of the medical device due to biofilm formation, which necessitates the replacement of the device. The objective of this study is to improve urological biomaterials to minimize microbial growth and reduce the incidence of CAUTIs. Challenges from mixed biofilm are crucial and need to be addressed in the development of new coating materials. Herein, an investigation highlighted the reduction of mixed biofilm overgrowth and attachment tendency on poly-2-hydroxyethyl methacrylate (p-HEMA) surface by loading the hydrogel with rifampicin (RIF), cefixime trihydrate (CFX), and combined ratios of RIF and CFX. Mixed biofilm-formation ability in (3:1) RIF: CFX-loading p-HEMA (F6) surface showed best tendency to resist form biofilm. Persistent antimicrobial activity increased in p-HEMA loaded with combined ratios of RIF and CFX surface compared to p-HEMA alone, antimicrobial activity lasted for 8 days. All fabricated films exhibited %cell viability higher than 75% on HEK 293 cells. The addition of RIF and CFX may improve the duration of urological device employment before replacement.}, } @article {pmid35272045, year = {2022}, author = {Shokouhfard, M and Kermanshahi, RK and Feizabadi, MM and Teimourian, S and Safari, F}, title = {Lactobacillus spp. derived biosurfactants effect on expression of genes involved in Proteus mirabilis biofilm formation.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {100}, number = {}, pages = {105264}, doi = {10.1016/j.meegid.2022.105264}, pmid = {35272045}, issn = {1567-7257}, mesh = {Biofilms ; *Cross Infection ; Female ; Humans ; Lactobacillus ; Male ; Proteus mirabilis ; *Urinary Tract Infections ; }, abstract = {Nosocomial infections (NIs) have been defined as infections ocuurring shortly after hospitalization or discharging from the hospital. It is associated with increased morbidities and mortalities. Proteus mirabilis considered as the hospital-acquired pathogen. The purpose of this study was to investigate the effect of Lactobacillus acidophilus-derived biosurfactant on P. mirabilis biofilm formation and flhDC/rsmA expression level (P. mirabilis standard strain ATCC 7002 and urinary infection isolated P. mirabilis strains). One of the potential strategies for the prevention of nosocomial infections is the use of probiotics. L. acidophilus was selected as a probiotic strain to produce biosurfactants. A biosurfactant reduces the adhesion of strains to microtiter plate and glass slide surfaces due to the reduction of surface tension. By using Real time PCR quantitation method we showed that biosurfactant significantly reduced rsmA expression whereas increased flhDC expression in P. mirabilis isolates. Several properties of P. mirabilis cells (biofilm formation, adhesion, and gene expression) were changed after L. acidophilus- derived biosurfactant treatment. In this study we showed that biosurfacant treatment can pave the way for a possible control of biofilm development. Based on our findings, we suggest that the prepared biosurfactant may interfere with adhesion of P. mirabilis to catheters and other devices.}, } @article {pmid35271716, year = {2022}, author = {Huang, X and Tian, S and Chen, X and Han, B and Xue, Y}, title = {Planktonic Growth and Biofilm Formation by Providencia rettgeri and Subsequent Effect of Tannic Acid Treatment under Food-Related Environmental Stress Conditions.}, journal = {Journal of food protection}, volume = {85}, number = {5}, pages = {849-858}, doi = {10.4315/JFP-21-289}, pmid = {35271716}, issn = {1944-9097}, mesh = {Biofilms ; *Plankton ; Providencia ; Sodium Chloride/pharmacology ; *Tannins/pharmacology ; }, abstract = {ABSTRACT: Providencia rettgeri is an opportunistic foodborne pathogen with a strong biofilm-forming ability in low-nutrition environments. However, information regarding the impact of simulated food processing conditions on P. rettgeri planktonic growth and biofilm formation is limited. Using response surface methodology (RSM), the combined effects of temperature (19 to 37°C), pH (5 to 9), and sodium chloride (NaCl) concentration (0.50 to 2.0%, w/v) were applied to construct planktonic growth and biofilm formation models for P. rettgeri. For both RSM models, an increase in NaCl concentration restricted P. rettgeri growth. Planktonic growth and biofilm formation were maximum at 27.83 and 25.41°C, respectively. Tannic acid (TA) is a highly effective antibacterial agent that inhibited planktonic and biofilm P. rettgeri under optimal growth conditions. The viability of P. rettgeri cells was decreased by TA treatment, which caused destruction of the cell membrane and production of endogenous reactive oxygen species. TA significantly inactivated P. rettgeri biofilms, as verified by observation. The obtained models in this study may be useful for describing the impact of temperature, pH, and NaCl concentration on the growth by P. rettgeri in the food processing environment and better understanding the impacts of food-related conditions on bacterial planktonic growth and biofilm formation. These results obtained for P. rettgeri planktonic cells and biofilms can provide a framework for removal strategies for other foodborne pathogens.}, } @article {pmid35268822, year = {2022}, author = {Oluwabusola, ET and Katermeran, NP and Poh, WH and Goh, TMB and Tan, LT and Diyaolu, O and Tabudravu, J and Ebel, R and Rice, SA and Jaspars, M}, title = {Inhibition of the Quorum Sensing System, Elastase Production and Biofilm Formation in Pseudomonas aeruginosa by Psammaplin A and Bisaprasin.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {5}, pages = {}, pmid = {35268822}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Disulfides ; Pancreatic Elastase ; *Pseudomonas aeruginosa/physiology ; *Quorum Sensing ; Tyrosine/analogs & derivatives ; Virulence Factors/metabolism ; }, abstract = {Natural products derived from marine sponges have exhibited bioactivity and, in some cases, serve as potent quorum sensing inhibitory agents that prevent biofilm formation and attenuate virulence factor expression by pathogenic microorganisms. In this study, the inhibitory activity of the psammaplin-type compounds, psammaplin A (1) and bisaprasin (2), isolated from the marine sponge, Aplysinellarhax, are evaluated in quorum sensing inhibitory assays based on the Pseudomonas aeruginosa PAO1 lasB-gfp(ASV) and rhlA-gfp(ASV) biosensor strains. The results indicate that psammaplin A (1) showed moderate inhibition on lasB-gfp expression, but significantly inhibited the QS-gene promoter, rhlA-gfp, with IC50 values at 14.02 μM and 4.99 μM, respectively. In contrast, bisaprasin (2) displayed significant florescence inhibition in both biosensors, PAO1 lasB-gfp and rhlA-gfp, with IC50 values at 3.53 μM and 2.41 μM, respectively. Preliminary analysis suggested the importance of the bromotyrosine and oxime functionalities for QSI activity in these molecules. In addition, psammaplin A and bisaprasin downregulated elastase expression as determined by the standard enzymatic elastase assay, although greater reduction in elastase production was observed with 1 at 50 μM and 100 μM. Furthermore, the study revealed that bisaprasin (2) reduced biofilm formation in P. aeruginosa.}, } @article {pmid35268586, year = {2022}, author = {Gao, K and Su, B and Dai, J and Li, P and Wang, R and Yang, X}, title = {Anti-Biofilm and Anti-Hemolysis Activities of 10-Hydroxy-2-decenoic Acid against Staphylococcus aureus.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {5}, pages = {}, pmid = {35268586}, issn = {1420-3049}, support = {ZR2020MC049//Shandong Provincial Natural Science Foundation/ ; }, mesh = {*Staphylococcus aureus ; }, abstract = {Persistent infections caused by Staphylococcus aureus biofilms pose a major threat to global public health. 10-Hydroxy-2-decenoic acid (10-HDA), a main fatty acid in royal jelly, has been shown to possess various biological activities. The purpose of this study was to explore the effects of 10-HDA on the biofilms and virulence of S. aureus and its potential molecular mechanism. Quantitative crystal violet staining indicated that 10-HDA significantly reduced the biofilm biomass at sub-minimum inhibitory concentration (MIC) levels (1/32MIC to 1/2MIC). Scanning electron microscope (SEM) observations demonstrated that 10-HDA inhibited the secretion of extracellular polymeric substances, decreased bacterial adhesion and aggregation, and disrupted biofilm architecture. Moreover, 10-HDA could significantly decrease the biofilm viability and effectively eradicated the mature biofilms. It was also found that the hemolytic activity of S. aureus was significantly inhibited by 10-HDA. qRT-PCR analyses revealed that the expressions of global regulators sarA, agrA, and α-hemolysin gene hla were downregulated by 10-HDA. These results indicate that 10-HDA could be used as a potential natural antimicrobial agent to control the biofilm formation and virulence of S. aureus.}, } @article {pmid35268559, year = {2022}, author = {Santra, HK and Maity, S and Banerjee, D}, title = {Production of Bioactive Compounds with Broad Spectrum Bactericidal Action, Bio-Film Inhibition and Antilarval Potential by the Secondary Metabolites of the Endophytic Fungus Cochliobolus sp. APS1 Isolated from the Indian Medicinal Herb Andrographis paniculata.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {5}, pages = {}, pmid = {35268559}, issn = {1420-3049}, mesh = {*Andrographis paniculata ; }, abstract = {Endophytes, being the co-evolution partners of green host plants, are factories of pharmaceutically valuable novel natural products. Cochliobolus sp. APS1, an endophyte of Andrographis paniculata (Green Chiretta), produces a plethora of natural bioactive compounds and the multipotent alkaloid Aziridine, 1-(2-aminoethyl)-, is the prime one among them. The isolate exhibited antibacterial, anti-biofilm, and antilarval potency. The MIC and MBC values of the ethyl-acetate culture extract ranged from 15.62 to 250 µg/mL against ten pathogenic microorganisms (including MRSA and VRSA). Killing kinetics data along with the leakage of macromolecules into the extracellular environment supports the cidal activity of the antibacterial principles. The broad spectrum antibacterial activity of Aziridine, 1-(2-aminoethyl)-, was optimized by a one-variable-at-a-time system coupled with response surface methodology, which led to a 45% enhancement of the antibacterial activity. The maximum response (22.81 ± 0.16 mm of zone of inhibition against MRSA) was marked in 250 mL Erlenmeyer flask containing 90 mL potato dextrose broth supplemented with (g%/L) glucose, 9.7; urea concentration, 0.74; with medium pH 6.48; after 8.76 days of incubation at 26 °C. APS1 strongly inhibited biofilm formation in the tested pathogenic microorganisms and acts as a larvicidal agent against the Dengue-vector Aedes aegypti. This is probably the first report of Aziridine, 1-(2-aminoethyl)-, from any endophytic source. Cochliobolus sp. APS1 possesses industrial importance for the production of bioactive alkaloids.}, } @article {pmid35268099, year = {2022}, author = {Babina, K and Salikhova, D and Polyakova, M and Svitich, O and Samoylikov, R and Ahmad El-Abed, S and Zaytsev, A and Novozhilova, N}, title = {The Effect of Oral Probiotics (Streptococcus Salivarius k12) on the Salivary Level of Secretory Immunoglobulin A, Salivation Rate, and Oral Biofilm: A Pilot Randomized Clinical Trial.}, journal = {Nutrients}, volume = {14}, number = {5}, pages = {}, pmid = {35268099}, issn = {2072-6643}, mesh = {Biofilms ; Humans ; Immunoglobulin A, Secretory ; Pilot Projects ; *Probiotics ; Saliva ; Salivation ; *Streptococcus salivarius ; }, abstract = {We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.}, } @article {pmid35266829, year = {2022}, author = {Stewart, PS and Williamson, KS and Boegli, L and Hamerly, T and White, B and Scott, L and Hu, X and Mumey, BM and Franklin, MJ and Bothner, B and Vital-Lopez, FG and Wallqvist, A and James, GA}, title = {Search for a Shared Genetic or Biochemical Basis for Biofilm Tolerance to Antibiotics across Bacterial Species.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {4}, pages = {e0002122}, pmid = {35266829}, issn = {1098-6596}, support = {P20 GM103474/GM/NIGMS NIH HHS/United States ; S10 OD028650/OD/NIH HHS/United States ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Carbon ; Plankton/genetics ; Pseudomonas aeruginosa/genetics ; Staphylococcus aureus/genetics ; }, abstract = {Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for 3 days and then challenged with respective antibiotics (ciprofloxacin, daptomycin, and tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells, and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of individual microorganisms in biofilms and contribute to antibiotic tolerance.}, } @article {pmid35266490, year = {2022}, author = {Wu, B and You, W and Wang, HL and Zhang, Z and Nie, X and Wang, F and You, YZ}, title = {Cyclic topology enhances the killing activity of polycations against planktonic and biofilm bacteria.}, journal = {Journal of materials chemistry. B}, volume = {10}, number = {25}, pages = {4823-4831}, doi = {10.1039/d2tb00194b}, pmid = {35266490}, issn = {2050-7518}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Bacteria ; Biofilms ; Mice ; *Plankton ; Polyelectrolytes ; }, abstract = {Bacterial biofilms, as a fortress to protect bacteria, enhance resistance to antibiotics because of their limited penetration, which has become a major threat to current anti-infective therapy. Antimicrobial polycations have received wide attention to kill planktonic bacteria because of their unique antimicrobial mechanism without drug resistance but it is still hard to kill the bacteria in the deep of the biofilm. Unlike linear polymers, the cyclic topology has been demonstrated with enhanced penetration in tissues, which is attributed to the lack of end groups, constrained conformation and a smaller hydrodynamic volume, opening a new sight of polycations in the antibacterial application against biofilms. Here, polycations with different topologies including linear and cyclic polycations were synthesized and their killing activity against planktonic and biofilm bacteria was studied. The experimental results showed the enhanced antibacterial activity of cyclic polycations for planktonic bacteria, which is presumably attributed to their smaller hydrodynamic volume, higher local density of positive charge and more interactions between cation units and the bacterial membrane than their linear analogues. Besides, cyclic polycations exhibit enhanced killing effect for biofilm bacteria and inhibition effect for biofilms with 5-7 times and 2-3 times enhancements than the linear polycations, respectively. Furthermore, an Escherichia coli infection model on mice was established and the therapeutic effects of cyclic and linear polycations were evaluated. Compared with the linear polycations, the cyclic polycations exhibited enhanced antibacterial activity with an ∼4 times increase, promoting the healing of the infected wounds. This work provides a new perspective in the development of antimicrobial polycations, which are promising therapeutic agents to kill planktonic and biofilm bacteria without drug resistance.}, } @article {pmid35265216, year = {2022}, author = {Sahli, C and Moya, SE and Lomas, JS and Gravier-Pelletier, C and Briandet, R and Hémadi, M}, title = {Recent advances in nanotechnology for eradicating bacterial biofilm.}, journal = {Theranostics}, volume = {12}, number = {5}, pages = {2383-2405}, pmid = {35265216}, issn = {1838-7640}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; Bacteria ; *Bacterial Infections/drug therapy/microbiology ; Biofilms ; *Nanoparticles ; Nanotechnology ; }, abstract = {Microorganisms grouped together into spatially-organized communities called biofilms, are the cause of dramatic chronic infections in plants, animals and humans. In this review, the characteristics of biofilms and their interactions with antimicrobials are first described. Limitations of antibiotic treatments are discussed, and state-of-the-art alternative approaches based on the use of polymer, lipid, organic, inorganic and hybrid nanoparticles are presented, highlighting recent achievements in the application of nanomaterials to the field of theranostics for the eradication of biofilm. The aim of this review is to present a complete vision of nanobiotechnology-based approaches for eradicating bacterial biofilms and fighting antimicrobial tolerance.}, } @article {pmid35264654, year = {2022}, author = {Swidan, NS and Hashem, YA and Elkhatib, WF and Yassien, MA}, title = {Antibiofilm activity of green synthesized silver nanoparticles against biofilm associated enterococcal urinary pathogens.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {3869}, pmid = {35264654}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/chemistry ; Biofilms ; Cinnamomum zeylanicum ; Enterococcus ; *Ginger ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry ; Silver/chemistry/pharmacology ; }, abstract = {Biofilm-formed enterococcal urinary tract clinical isolates (n = 92) were used for studying the antibiofilm activity of cinnamon, ginger, and chemical AgNPs. The average particle sizes of cinnamon, ginger, and chemical AgNPs were 8.7, 41.98, and 55.7 nm, respectively. The results of Fourier transform infrared analysis revealed that phytocompounds, such as cinnamaldehyde and gingerol, were the main compounds incorporated in the synthesis of cinnamon and ginger AgNPs, respectively. The purity and crystalline nature of the AgNPs have been confirmed by energy dispersive X-ray and X-ray Diffraction analysis. The results of antimicrobial activity showed that MIC of ginger, cinnamon, and chemical AgNPs were 37.64, 725.7, and 61.08 μg/ml, respectively. On studying the antibiofilm activity of AgNPs at sub-MIC values (1/2, 1/4, and 1/8 MIC), the results revealed that it was concentration dependent. Therefore, further studies were carried out to evaluate the antibiofilm activity of AgNPs at a concentration of 18 μg/ml. The results showed that ginger and chemical AgNPs reduced the formed biofilm to 39.14% and 65.32% and the number of adherent cells on the urinary catheter surface to 42.73% and 69.84%, respectively, as compared to that of the control, while cinnamon AgNPs showed no significant activity. Accordingly, ginger AgNPs had the most potent antibacterial and antiadherent activity against biofilm-associated enterococcal isolates.}, } @article {pmid35263182, year = {2022}, author = {Alvim, DCSS and Oliveira, LMA and Simões, LC and Costa, NS and Fracalanzza, SEL and Teixeira, LM and Ferreira, RBR and Pinto, TCA}, title = {Influence of Penicillin on Biofilm Formation by Streptococcus agalactiae Serotype Ia/CC23.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {28}, number = {5}, pages = {517-524}, doi = {10.1089/mdr.2021.0238}, pmid = {35263182}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Female ; Humans ; Microbial Sensitivity Tests ; Penicillins/pharmacology ; Pregnancy ; Serogroup ; *Streptococcal Infections/drug therapy/microbiology ; *Streptococcus agalactiae ; }, abstract = {Streptococcus agalactiae (Group B Streptococcus , GBS) is a major agent of perinatal infections. Biofilms have been associated with GBS colonization and disease, as well as with infection persistence and recurrence. Although GBS remains susceptible to beta-lactams, it is still unknown how sessile cells respond to these antibiotics. Here, we evaluated the effect of different concentrations of penicillin (3-48 mg/L) on in vitro biofilm formation by four GBS strains belonging to serotype Ia/clonal complexes23 that were recovered from the oropharynx or urine of pregnant women and were previously characterized as strong biofilm producers. All four GBS strains were fully susceptible to penicillin (minimum inhibitory concentration = 0.023 mg/L), but penicillin was not able to fully prevent biofilm formation by these GBS strains. Biofilms formed in the presence of penicillin had reduced biomasses and thickness, but they were still classified as strong. Penicillin significantly reduced the density of live cells, but higher penicillin concentrations did not lead to improved prevention of biofilm formation. Biofilms formed in the presence of penicillin had no channels or long cocci chains observed in penicillin-free biofilms. Overall, results highlight the concerning possible impacts of biofilm formation in penicillin-based treatment and preventive strategies of GBS infections, even when the bacterial strain involved is fully antibiotic-susceptible.}, } @article {pmid35258316, year = {2022}, author = {Phillips, ZN and Garai, P and Tram, G and Martin, G and Van Den Bergh, A and Husna, AU and Staples, M and Grimwood, K and Jennison, AV and Guillon, P and von Itzstein, M and Jennings, MP and Brockman, KL and Atack, JM}, title = {Characterization of the Phase-Variable Autotransporter Lav Reveals a Role in Host Cell Adherence and Biofilm Formation in Nontypeable Haemophilus influenzae.}, journal = {Infection and immunity}, volume = {90}, number = {4}, pages = {e0056521}, pmid = {35258316}, issn = {1098-5522}, support = {R21 DC016709/DC/NIDCD NIH HHS/United States ; }, mesh = {Biofilms ; *Haemophilus Infections ; *Haemophilus influenzae/genetics/metabolism ; Humans ; Type V Secretion Systems/genetics/metabolism ; }, abstract = {Lav is an autotransporter protein found in pathogenic Haemophilus and Neisseria species. Lav in nontypeable Haemophilus influenzae (NTHi) is phase-variable: the gene reversibly switches ON-OFF via changes in length of a locus-located GCAA(n) simple DNA sequence repeat tract. The expression status of lav was examined in carriage and invasive collections of NTHi, where it was predominantly not expressed (OFF). Phenotypic study showed lav expression (ON) results in increased adherence to human lung cells and denser biofilm formation. A survey of Haemophilus species genome sequences showed lav is present in ∼60% of NTHi strains, but lav is not present in most typeable H. influenzae strains. Sequence analysis revealed a total of five distinct variants of the Lav passenger domain present in Haemophilus spp., with these five variants showing a distinct lineage distribution. Determining the role of Lav in NTHi will help understand the role of this protein during distinct pathologies.}, } @article {pmid35258209, year = {2022}, author = {Tao, H and Qi, YT and Yu, D and Yang, L and Gu, Y and Li, YH}, title = {[Influence of Microplastics on the Development of Proteus Biofilm].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {43}, number = {3}, pages = {1455-1462}, doi = {10.13227/j.hjkx.202107084}, pmid = {35258209}, issn = {0250-3301}, mesh = {Biofilms ; *Microplastics/toxicity ; Plastics ; Polystyrenes ; Proteus ; *Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {Currently, research on the effects of microplastics (MPs) in biofilms has mainly been focused on the mature biofilm communities, with a lack of sufficient details on the influence on different development stages of biofilms. Proteus and 1 μm polystyrene microplastics (PS-MPs), which are widely found in the environment, were selected as the research objects to explore the effects of microplastics on biofilms at different developmental stages. In our study, the effects of PS-MPs on biofilm biomass, extracellular polymer composition(EPS), and extracellular enzyme activity were investigated using an exposure test. Our results showed that the effect of PS-MPs on biofilms at different stages was similar, but the effect was significantly reduced with the development of biofilms. Biofilms at different development stages had different sensitivities to microplastics. In the reversible attachment stage, the no observed effect concentration (NOEC) of EPS composition, reactive oxygen species (ROS) production, and extracellular enzyme activity were significantly lower than those in other stages; however, the NOEC of total antioxidant capacity (T-AOC) and lactate dehydrogenase (LDH) activity were similar. This may be the result of ROS-mediated protein oxidation, which can be reduced but not completely eliminated by EPS in other stages of biofilm. This indicates that PS-MPs has a low toxic effect on biofilm.}, } @article {pmid35258152, year = {2022}, author = {Jiang, Z and Yang, L and Yu, H and Hou, L and Shen, J}, title = {Synergistic denitrification and phosphorus removal performance of a biofilm-microflocculation system and its microbial community variations: A pilot-scale study for a wastewater treatment plant.}, journal = {Journal of applied microbiology}, volume = {132}, number = {5}, pages = {4007-4017}, doi = {10.1111/jam.15513}, pmid = {35258152}, issn = {1365-2672}, support = {51878171//National Natural Science Foundation of China/ ; }, mesh = {Bacteria/genetics ; Biofilms ; Bioreactors/microbiology ; Denitrification ; *Microbiota ; Nitrogen/analysis ; Phosphorus ; Sewage/microbiology ; Waste Disposal, Fluid/methods ; Wastewater/chemistry ; *Water Purification/methods ; }, abstract = {AIMS: For upgrading and reconstructing a municipal wastewater treatment plant, a biofilm-microflocculation filter system was designed and established towards synergistic improvement of denitrification and phosphorus removal from the secondary effluent.

METHODS AND RESULTS: The establishment of the biofilm-microflocculation filter system underwent several processes, including sludge inoculation, biofilm formation and polyaluminum chloride (PAC) addition as flocculating agent. Microbial community analysis indicated that the dominant denitrification bacteria of the biofilm filter were in the phylum Proteobacteria and the genera Hydrogenophaga and Dechloromonas. On the basis of the initiation of filter system under optimal parameters such as C/N ratio of 5.3, hydraulic retention time of 1.06 h and PAC of 5 mg L[-1] , approximately 75% COD, 80% TN and 75% TP could be effectively removed to satisfy discharge standards. Comparing the variations of microbial community structure at the genus level during the operating period of the filter system, it was found that the relative abundance of denitrification bacteria merely shifted from 53.14% to 48.76%, demonstrating that the effect of PAC addition on the main micro-organisms is marginal.

CONCLUSIONS: From the above results, it can be verified that the established biofilm-microflocculation filter system has practical and reliable performance for simultaneous biological denitrification and phosphorus removal.

This study provides a reference method for improving the advanced treatment of wastewater plant secondary effluent.}, } @article {pmid35257940, year = {2022}, author = {Schestakow, A and Pütz, N and Guth, MS and Eisenmenger, TA and Dudek, J and Hannig, M}, title = {Influence of a hydroxyapatite suspension on 48-h dental biofilm formation in-situ.}, journal = {Archives of oral biology}, volume = {136}, number = {}, pages = {105388}, doi = {10.1016/j.archoralbio.2022.105388}, pmid = {35257940}, issn = {1879-1506}, mesh = {Animals ; Biofilms ; Cattle ; *Chlorhexidine/pharmacology ; Dental Enamel ; *Durapatite/pharmacology ; Humans ; Saliva ; }, abstract = {OBJECTIVE: The aim of the present in-situ study was to investigate anti-adherent properties of mouthrinses containing hydroxyapatite (HAP) nanoparticles on oral biofilm formation.

DESIGN: Biofilm was formed for 48 h on bovine enamel or dentine specimens that were fixed to maxillary splints and worn intraoral by six volunteers. During biofilm formation, rinsing was performed with sterile water, HAP (5%) or chlorhexidine (0.2%) according to two different rinsing protocols in order to assess substantivity. Scanning electron microscopy was used to investigate biofilm coverage of specimens, biofilm thickness and morphology. In addition, saliva samples were collected and analysed with transmission electron microscopy.

RESULTS: Rinsing with sterile water or HAP resulted in 2.1 or 2.3 µm thick biofilms, respectively, covering more than half of specimen' surfaces. Despite single deposits of nanoparticles in saliva and biofilm, HAP did not inhibit biofilm formation. Chlorhexidine on the other hand significantly reduced biofilm thickness and coverage.

CONCLUSIONS: Mouthrinses containing HAP nanoparticles showed no anti-adherent effects during 48 h of biofilm formation in-situ.}, } @article {pmid35257684, year = {2022}, author = {Salem, AS and Tompkins, GR and Cathro, PR}, title = {Alkaline Tolerance and Biofilm Formation of Root Canal Isolates of Enterococcus faecalis: An In Vitro Study.}, journal = {Journal of endodontics}, volume = {48}, number = {4}, pages = {542-547.e4}, doi = {10.1016/j.joen.2022.01.006}, pmid = {35257684}, issn = {1878-3554}, mesh = {Biofilms ; *Dental Pulp Cavity ; *Enterococcus faecalis ; Root Canal Therapy ; }, abstract = {INTRODUCTION: The aim of this study was to compare the effects of glucose and glycerol (provided as principal fermentable supplements) on alkaline tolerance and biofilm-forming capabilities of root canal-derived strains of Enterococcus faecalis and those from other environments.

METHODS: The planktonic growth kinetics and the biofilm-forming capabilities of E. faecalis isolates (identified by 16S ribosomal DNA sequencing) were compared when supplied with glucose and glycerol at pH levels of 8 and 11 in a microtiter plate. The metabolic activity of the biofilms plate that formed at a neutral pH level (supplied with either glucose or glycerol) was measured after subsequent adjustment to a pH level of 11.

RESULTS: Ten isolates (7 from root canals and 3 from other sources) were examined. The lag phase and the doubling time increased under elevated alkalinity irrespective of either the fermentable supplement (glucose or glycerol) or the origin of the isolate. Biofilm formation and metabolic activity varied among strains, but neither was related to the source of isolation. In general, biofilm formation was enhanced when grown in glucose compared with glycerol and at a pH of 8 compared with a pH of 11 (irrespective of the fermentable supplement). The provision of glycerol did not increase either the planktonic growth rate or biofilm development compared with glucose but significantly increased the metabolic activity of biofilms, especially at a pH of 11 compared with a pH of 8.

CONCLUSIONS: In the nutrient-deprived environment of a necrotic or root-filled root canal, glycerol may be an alternative energy source that can promote increased metabolic activity of E. faecalis under alkaline treatment conditions.}, } @article {pmid35257605, year = {2022}, author = {Scherl, DS and Coffman, L and Mansoor, A and Rajwa, B and Patsekin, V and Robinson, JP}, title = {A Semi-Automated Method for Measuring Biofilm Accumulation on the Teeth Using Quantitative Light-Induced Fluorescence in Dogs and Cats.}, journal = {Journal of veterinary dentistry}, volume = {39}, number = {2}, pages = {122-132}, doi = {10.1177/08987564221081991}, pmid = {35257605}, issn = {2470-4083}, mesh = {Animals ; Biofilms ; *Cat Diseases/diagnosis ; Cats ; *Dental Caries/veterinary ; *Dog Diseases/diagnosis ; Dogs ; Fluorescence ; Humans ; Light ; *Quantitative Light-Induced Fluorescence/veterinary ; Reproducibility of Results ; }, abstract = {Oral health conditions (eg, plaque, calculus, gingivitis) cause morbidity and pain in companion animals. Thus, developing technologies that can ameliorate the accumulation of oral biofilm, a critical factor in the progression of these conditions, is vital. Quantitative light-induced fluorescence (QLF) is a method to quantify oral substrate accumulation, and therefore, it can assess biofilm attenuation of different products. New software has recently been developed that automates aspects of the procedure. However, few QLF studies in companion animals have been performed. QLF was used to collect digital images of oral substrate accumulation on the teeth of dogs and cats to demonstrate the ability of QLF to discriminate between foods known to differentially inhibit oral substrate accumulation. Images were taken as a function of time and diet. Software developed by the Cytometry Laboratory, Purdue University quantified biofilm coverage. Intra- and intergrader reproducibility was also assessed, as was a comparison of the results of the QLF software with those of an experienced grader using undisclosed coverage-only metrics similar to those used for the Logan and Boyce index. Quantification of oral substrate accumulation using QLF-derived images demonstrated the ability to distinguish between dental diets known to differentially inhibit oral biofilm accumulation. Little variance in intra- and intergrader reproducibility was observed, and the comparison between the experienced Logan and Boyce grader and the QLF software yielded a concordance correlation coefficient of 0.89 (95% CI = 0.84, 0.92). These results show that QLF is a useful tool that allows the semi-automated quantification of the accumulation of oral biofilm in companion animals.}, } @article {pmid35255424, year = {2022}, author = {Hou, C and Jiang, X and Chen, D and Zhang, X and Liu, X and Mu, Y and Shen, J}, title = {Ag-TiO2/biofilm/nitrate interface enhanced visible light-assisted biodegradation of tetracycline: The key role of nitrate as the electron accepter.}, journal = {Water research}, volume = {215}, number = {}, pages = {118212}, doi = {10.1016/j.watres.2022.118212}, pmid = {35255424}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Electrons ; Light ; *Nitrates ; Tetracycline ; Titanium ; }, abstract = {Due to the pivotal role of Ag-TiO2/biofilm/nitrate interface, enhanced visible light-assisted biodegradation of tetracycline (TC) in anoxic system was realized through both batch experiment and long-term operation in this study. The results of the batch experiment elucidated that 50 mg L[-1] TC could be completely removed within 10 h in Ag-TiO2/biofilm/nitrate system. The continuous flow experiment was operated for 75 d to evaluate the performance and stability of Ag-TiO2/biofilm/nitrate system. TC removal efficiency in Ag-TiO2/biofilm/nitrate system was as high as 92.4 ± 1.6% at influent TC concentration of 50 mg L[-1] TC and hydraulic retention time (HRT) of 10 h, which would be attributed to the promoted separation of photoholes and photoelectrons at the presence of nitrate as electron acceptor. Facilitated electron transfer between semiconductor and biofilm was beneficial for enhancing TC biodegradation, thus lowering toxicity of intermediate products and promoting microbial activity. Moreover, the species related to TC biodegradation (Rhodopseudomonas, Phreatobacter and Stenotrophomonas), denitrification (Thauera) and electron transfer (Delftia) were enriched at Ag-TiO2/biofilm/nitrate interface. Besides, a possible mechanism involved in enhanced TC degradation and nitrogen removal at Ag-TiO2/biofilm/nitrate interface was proposed. This study provided a novel and promising strategy to enhance recalcitrant TC removal from industrial wastewater.}, } @article {pmid35255215, year = {2022}, author = {Thorn, CR and Wignall, A and Kopecki, Z and Kral, A and Prestidge, CA and Thomas, N}, title = {Liquid Crystal Nanoparticles Enhance Tobramycin Efficacy in a Murine Model of Pseudomonas aeruginosa Biofilm Wound Infection.}, journal = {ACS infectious diseases}, volume = {8}, number = {4}, pages = {841-854}, doi = {10.1021/acsinfecdis.1c00606}, pmid = {35255215}, issn = {2373-8227}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Disease Models, Animal ; *Liquid Crystals ; Mice ; *Nanoparticles ; *Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa ; Tobramycin/pharmacology ; *Wound Infection/drug therapy ; }, abstract = {Chronic Pseudomonas aeruginosa wound infections are highly prevalent and often untreatable due to biofilm formation, resulting in high antimicrobial tolerance. Standard antibiotic therapy for P. aeruginosa infections involves tobramycin, yet it is highly ineffective as monotherapy as tobramycin cannot penetrate the biofilm to elicit its antimicrobial effect. Lipid liquid crystal nanoparticles (LCNPs) have previously been shown to increase the antimicrobial efficacy and penetration of tobramycin against P. aeruginosa biofilms in vitro and ex vivo. Here, for the first time, we have developed a chronic P. aeruginosa biofilm infection in full-thickness wounds in mice to examine the potential of LCNPs to improve the effect of tobramycin, preclinically. After three doses, administered once a day, tobramycin-LCNPs significantly reduced the P. aeruginosa bacterial load in murine wounds 1000-fold more than unformulated tobramycin, which in turn showed no significant difference to the saline control treatment. Consistent with the improved P. aeruginosa eradication, the tobramycin-LCNPs promoted wound healing. In comparison to previous in vitro and ex vivo data, we show a strong in vitro-in vivo correlation between P. aeruginosa biofilm infection models. The enhanced activity of tobramycin-LCNPs in vivo in the preclinical murine model demonstrates the strong potential of LCNPs as a next-generation formulation approach to improve the efficacy of tobramycin against P. aeruginosa biofilm wound infections.}, } @article {pmid35254131, year = {2022}, author = {Kerkaert, JD and Le Mauff, F and Wucher, BR and Beattie, SR and Vesely, EM and Sheppard, DC and Nadell, CD and Cramer, RA}, title = {An Alanine Aminotransferase Is Required for Biofilm-Specific Resistance of Aspergillus fumigatus to Echinocandin Treatment.}, journal = {mBio}, volume = {13}, number = {2}, pages = {e0293321}, pmid = {35254131}, issn = {2150-7511}, support = {R01 AI130128/AI/NIAID NIH HHS/United States ; P20 GM113132/GM/NIGMS NIH HHS/United States ; R01AI146121//HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; T32AI007519//HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; R01AI130128//HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; STANTO15R0//Cystic Fibrosis Foundation (CFF)/ ; R01 AI146121/AI/NIAID NIH HHS/United States ; CRAMER1GO19//Cystic Fibrosis Foundation (CFF)/ ; P20GM113132//HHS | NIH | National Institute of General Medical Sciences (NIGMS)/ ; }, mesh = {Alanine/metabolism/pharmacology/therapeutic use ; Alanine Transaminase/metabolism/pharmacology ; Animals ; Antifungal Agents/metabolism/pharmacology/therapeutic use ; *Aspergillus fumigatus ; Biofilms ; Disease Models, Animal ; Echinocandins/metabolism/pharmacology/therapeutic use ; *Invasive Pulmonary Aspergillosis ; Mammals ; Mice ; Oxygen/metabolism ; }, abstract = {Alanine metabolism has been suggested as an adaptation strategy to oxygen limitation in organisms ranging from plants to mammals. Within the pulmonary infection microenvironment, Aspergillus fumigatus forms biofilms with steep oxygen gradients defined by regions of oxygen limitation. An alanine aminotransferase, AlaA, was observed to function in alanine catabolism and is required for several aspects of A. fumigatus biofilm physiology. Loss of alaA, or its catalytic activity, results in decreased adherence of biofilms through a defect in the maturation of the extracellular matrix polysaccharide galactosaminogalactan (GAG). Additionally, exposure of cell wall polysaccharides is also impacted by loss of alaA, and loss of AlaA catalytic activity confers increased biofilm susceptibility to echinocandin treatment, which is correlated with enhanced fungicidal activity. The increase in echinocandin susceptibility is specific to biofilms, and chemical inhibition of alaA by the alanine aminotransferase inhibitor β-chloro-l-alanine is sufficient to sensitize A. fumigatus biofilms to echinocandin treatment. Finally, loss of alaA increases susceptibility of A. fumigatus to in vivo echinocandin treatment in a murine model of invasive pulmonary aspergillosis. Our results provide insight into the interplay of metabolism, biofilm formation, and antifungal drug resistance in A. fumigatus and describe a mechanism of increasing susceptibility of A. fumigatus biofilms to the echinocandin class of antifungal drugs. IMPORTANCE Aspergillus fumigatus is a ubiquitous filamentous fungus that causes an array of diseases depending on the immune status of an individual, collectively termed aspergillosis. Antifungal therapy for invasive pulmonary aspergillosis (IPA) or chronic pulmonary aspergillosis (CPA) is limited and too often ineffective. This is in part due to A. fumigatus biofilm formation within the infection environment and the resulting emergent properties, particularly increased antifungal resistance. Thus, insights into biofilm formation and mechanisms driving increased antifungal drug resistance are critical for improving existing therapeutic strategies and development of novel antifungals. In this work, we describe an unexpected observation where alanine metabolism, via the alanine aminotransferase AlaA, is required for several aspects of A. fumigatus biofilm physiology, including resistance of A. fumigatus biofilms to the echinocandin class of antifungal drugs. Importantly, we observed that chemical inhibition of alanine aminotransferases is sufficient to increase echinocandin susceptibility and that loss of alaA increases susceptibility to echinocandin treatment in a murine model of IPA. AlaA is the first gene discovered in A. fumigatus that confers resistance to an antifungal drug specifically in a biofilm context.}, } @article {pmid35254124, year = {2022}, author = {Trinetta, V and Mendez, EA and Hoffmann, M and Zheng, J}, title = {Whole-Genome Sequences of Two Listeria monocytogenes Biofilm Formers.}, journal = {Microbiology resource announcements}, volume = {11}, number = {4}, pages = {e0106221}, pmid = {35254124}, issn = {2576-098X}, abstract = {Listeria monocytogenes strains from different lineages show different biofilm-forming abilities. In this study, two strains of L. monocytogenes were whole genome sequenced using single-molecule real-time (SMRT) technology and characterized.}, } @article {pmid35254120, year = {2022}, author = {Fleeman, RM and Davies, BW}, title = {Polyproline Peptide Aggregation with Klebsiella pneumoniae Extracellular Polysaccharides Exposes Biofilm Associated Bacteria.}, journal = {Microbiology spectrum}, volume = {10}, number = {2}, pages = {e0202721}, pmid = {35254120}, issn = {2165-0497}, support = {K99 AI163295/AI/NIAID NIH HHS/United States ; R01 AI125337/AI/NIAID NIH HHS/United States ; R01 AI148419/AI/NIAID NIH HHS/United States ; R21 AI159203/AI/NIAID NIH HHS/United States ; }, mesh = {Antimicrobial Cationic Peptides ; Bacterial Capsules ; Biofilms ; Humans ; *Klebsiella Infections/microbiology ; *Klebsiella pneumoniae ; Peptides ; Polysaccharides ; Polysaccharides, Bacterial ; }, abstract = {Klebsiella pneumoniae produces a thick capsule layer composed of extracellular polysaccharides protecting the bacterial cells from clearance by innate host immunity during infection. Here we characterize the interactions of a structurally diverse set of host defense peptides with K. pneumoniae extracellular polysaccharides. Remarkably, we found that all host defense peptides were active against a diverse set of K. pneumoniae strains, including hypermucoviscous strains with extensive capsule production, and aggregated with extracted capsule. Interestingly, the polyproline peptide bac7 (1-35), was the most potent antimicrobial and induced the most capsule aggregation. In addition to capsule aggregation, we found that bac7 (1-35) could also disrupt pre-formed hypermucoviscous K. pneumoniae biofilm. Further analysis using scanning electron microscopy revealed the biofilm matrix of a hypermucoviscous strain is removed by bac7 (1-35) exposing associated bacterial cells. This is the first description of a host defense peptide interacting with capsular and biofilm extracellular polysaccharides to expose cells from a K. pneumoniae biofilm matrix and suggests that features of polyproline peptides may be uniquely suited for extracellular polysaccharide interactions. IMPORTANCE Klebsiella pneumoniae bacterial infections are a major threat to human health as mortality rates are steadily on the rise. A defining characteristic of K. pneumoniae is the robust polysaccharide capsule that aids in resistance to the human immune system. We have previously discovered that a synthetic peptide could aggregate with capsule polysaccharides and disrupt the capsule of K. pneumoniae. Here we describe that host defense peptides also aggregate with capsule produced from hypermucoviscous K. pneumoniae, revealing this mechanism is shared by natural peptides. We found the polyproline peptide bac7 (1-35) had the greatest antimicrobial activity and caused the most capsule aggregation. Interestingly, bac7 (1-35) also removed the biofilm matrix of hypermucoviscous K. pneumoniae exposing the associated bacterial cells. This is the first description of a polyproline peptide interacting with capsular and biofilm polysaccharides to expose cells from a K. pneumoniae biofilm matrix.}, } @article {pmid35253195, year = {2022}, author = {Alghofaili, F}, title = {Use of bacterial culture supernatants as anti-biofilm agents against Pseudomonas aeruginosa and Klebsiella pneumoniae.}, journal = {European review for medical and pharmacological sciences}, volume = {26}, number = {4}, pages = {1388-1397}, doi = {10.26355/eurrev_202202_28132}, pmid = {35253195}, issn = {2284-0729}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cross Infection ; Humans ; Klebsiella pneumoniae ; *Pseudomonas aeruginosa ; Salmonella ; Salmonella typhimurium/physiology ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa and Klebsiella pneumoniae are the most pervasive and challenging agents of bacterial nosocomial infections. Previous studies indicated that the microbial biofilms formed by these bacteria may play important roles in their pathogenesis and resistance to phagocytosis and antibiotics. The aim of this study was to explore the anti-biofilm activity of culture supernatants of Salmonella enterica subsp. enteric serovar Typhimurium SL1344 and P. aeruginosa PA01 against biofilms formed by P. aeruginosa PA01 and K. pneumoniae KR3167, respectively.

MATERIALS AND METHODS: Biofilm formation was quantified by crystal violet staining. A modified method was applied to separate planktonic and biofilm-forming cells. The viable cells in the planktonic and biofilm phases were quantitated by viable plate count. Dual-species interactions between P. aeruginosa PAO1 and Salmonella enterica subsp. enterica serovar Typhimurium SL1344 were investigated using different cell density ratios.

RESULTS: Biofilm formation of P. aeruginosa PA01 was significantly inhibited by the heat resistant components from the culture supernatants of Salmonella enterica subsp. enterica serovar Typhimurium. Biofilm formed by K. pneumoniae KR3167 was also inhibited by the culture supernatants of P. aeruginosa PA01. The supernatants obtained from planktonic cell caused greater biofilm reduction than those extracted from biofilm-forming cells.

CONCLUSIONS: This study is the first to report that sterile crude supernatants extracted from the cultures of Salmonella enterica and P. aeruginosa significantly inhibited biofilm formation of P. aeruginosa and K. pneumoniae, respectively. The active agents in the culture supernatants responsible for biofilm inhibition have not been determined yet. The culture supernatants of Salmonella enterica and P. aeruginosa should be further studied for their therapeutic potential to reduce biofilm formation produced by bacteria causing nosocomial infections.}, } @article {pmid35250938, year = {2022}, author = {Skutlaberg, DH and Wiker, HG and Mylvaganam, H and , and Norrby-Teglund, A and Skrede, S}, title = {Consistent Biofilm Formation by Streptococcus pyogenes emm 1 Isolated From Patients With Necrotizing Soft Tissue Infections.}, journal = {Frontiers in microbiology}, volume = {13}, number = {}, pages = {822243}, pmid = {35250938}, issn = {1664-302X}, abstract = {OBJECTIVES: Biofilm formation has been demonstrated in muscle and soft tissue samples from patients with necrotizing soft tissue infection (NSTI) caused by Streptococcus pyogenes, but the clinical importance of this observation is not clear. Although M-protein has been shown to be important for in vitro biofilm formation in S. pyogenes, the evidence for an association between emm type and biofilm forming capacity is conflicting. Here we characterize the biofilm forming capacity in a collection of S. pyogenes isolates causing NSTI, and relate this to emm type of the isolates and clinical characteristics of the patients.

METHODS: Bacterial isolates and clinical data were obtained from NSTI patients enrolled in a multicenter prospective observational study. Biofilm forming capacity was determined using a microtiter plate assay.

RESULTS: Among 57 cases, the three most frequently encountered emm types were emm1 (n = 22), emm3 (n = 13), and emm28 (n = 7). The distribution of biofilm forming capacity in emm1 was qualitatively (narrow-ranged normal distribution) and quantitatively (21/22 isolates in the intermediate range) different from other emm types (wide ranged, multimodal distribution with 5/35 isolates in the same range as emm1). There were no significant associations between biofilm forming capacity and clinical characteristics of the patients.

CONCLUSIONS: The biofilm forming capacity of emm1 isolates was uniform and differed significantly from other emm types. The impact of biofilm formation in NSTI caused by S. pyogenes on clinical outcomes remains uncertain.}, } @article {pmid35249674, year = {2022}, author = {Latorre, MC and Alonso, B and Cruces, R and Sanz, A and Muñoz, P and Guembe, M}, title = {The classification of Staphylococcus aureus strains by biofilm production differs depending on the method used.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {40}, number = {3}, pages = {134-137}, doi = {10.1016/j.eimce.2020.11.021}, pmid = {35249674}, issn = {2529-993X}, mesh = {Biofilms ; Humans ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {INTRODUCTION: Strains can be classified in terms of biofilm production from quantitative absorbance values collectively by dividing strains into tertile ranks or individually by calculating the optical density for the negative control. However, these methods have not been compared in a large sample of Staphylococcus aureus strains. Therefore, our objective was to analyze the agreement between both methods in terms of biomass production and metabolic activity of their biofilm.

METHODS: We classified 233 S. aureus strains by biomass production and metabolic activity using the crystal violet and XTT assays, respectively. Strains were classified as low, moderate, or high biofilm producers according to tertile or optical density.

RESULTS: We found no agreement between both methods (p<0.001 and p=0.028, respectively).

CONCLUSIONS: We consider strains' biofilm classification by optical density to be a more reliable method, as it depends on the individual absorbance of each strain.}, } @article {pmid35248909, year = {2022}, author = {Zhang, Y and Qv, Z and Wang, J and Yang, Y and Chen, X and Wang, J and Zhang, Y and Zhu, L}, title = {Natural biofilm as a potential integrative sample for evaluating the contamination and impacts of PFAS on aquatic ecosystems.}, journal = {Water research}, volume = {215}, number = {}, pages = {118233}, doi = {10.1016/j.watres.2022.118233}, pmid = {35248909}, issn = {1879-2448}, mesh = {Biofilms ; Ecosystem ; Environmental Monitoring ; *Fluorocarbons/analysis ; *Water Pollutants, Chemical/analysis ; }, abstract = {Natural biofilm can be a suitable medium for the monitoring of pollutants. Limited information is currently available regarding the occurrence of per- and polyfluoroalkyl substances (PFAS) in periphytic biofilm and low-trophic level organisms of freshwater ecosystems. In this study, surface water, biofilm, phytoplankton, and freshwater snails were collected from Taihu Lake, China, and characterized for 16 PFAS, including legacy compounds (PFSAs/PFCAs) and PFAS of emerging concern (fluorotelomer sulfonates and F-53B). The colonized biofilms effectively bioaccumulated PFAS from water, with the total concentration (∑PFAS) in the range of 1.96-20.1 ng/g wet weight, and the bioaccumulation factor increased with the PFAS log Kow values. As compared with phytoplankton, the ∑PFAS in biofilms displayed a stronger correlation with those in water. PFAS distinctly biomagnified from the biofilm to freshwater snail, with the biomagnification factor in the range of 3.09 ± 2.03 - 17.8 ± 10.2, implying the important role of biofilm in PFAS transfer in aquatic environment. Extracellular proteins production in biofilm increased with the water PFAS concentrations. The total extracellular polymeric substances (EPS) content increased with the water PFAS concentration firstly and then declined to a steady level, while the algal chlorophyll level exhibited a similar relationship with the PFAS in biofilm. High PFAS levels were also associated with depressed alpha diversity of fungal community in biofilms. Biofilm appears as a relevant indicator to characterize the occurrence of PFAS in aquatic ecosystems.}, } @article {pmid35247736, year = {2022}, author = {Cui, F and Li, T and Wang, D and Yi, S and Li, J and Li, X}, title = {Recent advances in carbon-based nanomaterials for combating bacterial biofilm-associated infections.}, journal = {Journal of hazardous materials}, volume = {431}, number = {}, pages = {128597}, doi = {10.1016/j.jhazmat.2022.128597}, pmid = {35247736}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/chemistry ; *Bacterial Infections/drug therapy/microbiology ; Biofilms ; Carbon/pharmacology ; Humans ; *Nanostructures ; Quorum Sensing ; }, abstract = {The prevalence of bacterial pathogens among humans has increased rapidly and poses a great threat to health. Two-thirds of bacterial infections are associated with biofilms. Recently, nanomaterials have emerged as anti-biofilm agents due to their enormous potential for combating biofilm-associated infections and infectious disease management. Among these, relatively high biocompatibility and unique physicochemical properties of carbon-based nanomaterials (CBNs) have attracted wide attention. This review presented the current advances in anti-biofilm CBNs. Different kinds of CBNs and their physicochemical characteristics were introduced first. Then, the various potential mechanisms underlying the action of anti-biofilm CBNs during different stages were discussed, including anti-biofouling activity, inhibition of quorum sensing, photothermal/photocatalytic inactivation, oxidative stress, and electrostatic and hydrophobic interactions. In particular, the review focused on the pivotal role played by CBNs as anti-biofilm agents and delivery vehicles. Finally, it described the challenges and outlook for the development of more efficient and bio-safer anti-biofilm CBNs.}, } @article {pmid35247153, year = {2022}, author = {Chakrabarty, S and Mishra, MP and Bhattacharyay, D}, title = {Targeting Microbial Bio-film: an Update on MDR Gram-Negative Bio-film Producers Causing Catheter-Associated Urinary Tract Infections.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {6}, pages = {2796-2830}, pmid = {35247153}, issn = {1559-0291}, mesh = {*Anti-Bacterial Agents/pharmacology ; Bacteria ; Catheters/adverse effects ; Gram-Negative Bacteria ; Humans ; Microbial Sensitivity Tests ; *Urinary Tract Infections/drug therapy/prevention & control ; }, abstract = {In every age group, urinary tract infection (UTI) is found as a major recurrence infectious disorder. Bio-films produced by bacteria perform a vital role in causing infection in the tract of the urinary system, leading to recurrences and relapses. The purpose of this review is to present the role and mechanism of bio-film producing MDR Gram-negative bacteria causing UTI, their significance, additionally the challenges for remedy and prevention of catheter-associated UTI. This work appreciates a new understanding of bio-film producers which are having multi-drug resistance capability and focuses on the effect and control of bio-film producing uropathogenic bacteria related to catheterization. We have tried to analyze approaches to target bio-film and reported phytochemicals with anti-bio-film activity also updated on anti-bio-film therapy.}, } @article {pmid35246599, year = {2022}, author = {Jaago, M and Pupina, N and Rähni, A and Pihlak, A and Sadam, H and Vrana, NE and Sinisalo, J and Pussinen, P and Palm, K}, title = {Antibody response to oral biofilm is a biomarker for acute coronary syndrome in periodontal disease.}, journal = {Communications biology}, volume = {5}, number = {1}, pages = {205}, pmid = {35246599}, issn = {2399-3642}, support = {PRG573//Eesti Teadusagentuur (Estonian Research Council)/ ; }, mesh = {*Acute Coronary Syndrome/diagnosis ; Antibody Formation ; Biofilms ; Biomarkers ; *Coronary Artery Disease ; Epitopes ; Humans ; *Periodontitis/diagnosis ; }, abstract = {Cumulative evidence over the last decades have supported the role of gum infections as a risk for future major cardiovascular events. The precise mechanism connecting coronary artery disease (CAD) with periodontal findings has remained elusive. Here, we employ next generation phage display mimotope-variation analysis (MVA) to identify the features of dysfunctional immune system that associate CAD with periodontitis. We identify a fine molecular description of the antigenic epitope repertoires of CAD and its most severe form - acute coronary syndrome (ACS) by profiling the antibody reactivity in a patient cohort with invasive heart examination and complete clinical oral assessment. Specifically, we identify a strong immune response to an EBV VP26 epitope mimicking multiple antigens of oral biofilm as a biomarker for the no-CAD group. With a 2-step biomarker test, we stratify subjects with periodontitis from healthy controls (balanced accuracy 84%), and then assess the risk for ACS with sensitivity 71-89% and specificity 67-100%, depending on the oral health status. Our findings highlight the importance of resolving the immune mechanisms related to severe heart conditions such as ACS in the background of oral health. Prospective validation of these findings will support incorporation of these non-invasive biomarkers into clinical practice.}, } @article {pmid35246302, year = {2022}, author = {Sushmitha, TJ and Rajeev, M and Toleti, SR and Pandian, SK}, title = {Complete genome sequence of Halomonas boliviensis strain kknpp38, a chlorine-resistant bacterium isolated from the early-stage marine biofilm.}, journal = {Marine genomics}, volume = {62}, number = {}, pages = {100890}, doi = {10.1016/j.margen.2021.100890}, pmid = {35246302}, issn = {1876-7478}, mesh = {Biofilms ; *Chlorine/metabolism ; Genes, Bacterial ; Genome, Bacterial ; *Halomonas/genetics ; }, abstract = {H. boliviensis strain kknpp38 is a dense exopolysaccharide (EPS) producing bacterium, isolated from the early-stage (72-h-old) of marine biofilm. Laboratory experiments demonstrated that this isolate forms a potent biofilm on various artificial substrata viz. polystyrene, stainless steel as well as titanium and possesses high tolerance to chlorine disinfection. To determine the genes and biosynthetic pathways involved in the EPS production, whole-genome sequencing was performed using high-throughput Illumina tag sequencing. The high-quality reads were first de novo assembled using Unicycler genome assembler (version 0.4.9b) and then annotated using Prokka (version 1.13). The complete genome comes from one circular chromosome containing 4.96 Mbp DNA with G + C content of 55%, and encompasses genes encoding 4476 proteins, 2 rRNAs, and 57 tRNAs. Intriguingly, genomic analysis revealed the existence of genes involved in ATP-binding cassette (ABC) transporter-dependent EPS biosynthesis pathways (ugd, ugd2, galU). In addition, we identified genes involved in ectoine (ectA, ectB, ectC, ectD) and polyhydroxyalkanoates (PHAs; fabA, fabB, fabD, fabF, fabH, fabV, fabZ, phaC, phaD, phaG, phaR, phaZ1) production, which are known to involve in bacterial adaptation in saline environment. The outcomes of this study expand scientific understanding on the genes and pathways involved in EPS biosynthesis by marine bacteria.}, } @article {pmid35246026, year = {2022}, author = {Pourhajibagher, M and Keshavarz Valian, N and Bahador, A}, title = {Theranostic nanoplatforms of emodin-chitosan with blue laser light on enhancing the anti-biofilm activity of photodynamic therapy against Streptococcus mutans biofilms on the enamel surface.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {68}, pmid = {35246026}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; *Chitosan/pharmacology ; *Dental Caries/drug therapy ; Dental Enamel ; *Emodin/pharmacology ; Humans ; Lactic Acid/pharmacology ; Lasers ; *Photochemotherapy ; Photosensitizing Agents/pharmacology ; Precision Medicine ; Reactive Oxygen Species/pharmacology ; Streptococcus mutans ; }, abstract = {BACKGROUND: Combining photosensitizer and light irradiation, named antimicrobial photodynamic therapy (aPDT) is an adjuvant therapy for eliminating microbial biofilms. This ex vivo study evaluates the effect of anti-biofilm activity of aPDT based on emodin-chitosan nanoparticles (Emo-CS-NPs) plus blue laser light against Streptococcus mutans biofilm on the enamel surface.

MATERIALS: After determination of the fractional inhibitory concentration index of Emo and CS by checkerboard array assay, Emo-CS-NPs were synthesized and characterized. Following treatment of pre-formed S. mutans biofilms on the enamel slabs, cellular uptake of Emo-CS-NPs and intracellular reactive oxygen species (ROS) production were determined. The anti-biofilm and anti-metabolic activities of aPDT were investigated. Eventually, lactic acid production capacity, concentrations of S. mutans extracellular DNA (eDNA) levels, and expression of the gene involved in the biofilm formation (gtfB) were evaluated.

RESULTS: The maximum uptake of Emo-CS-NPs occurs in an incubation time of 5 min. When irradiated, Emo-CS-NPs were photoactivated, generating ROS, and led to a decrease in the cell viability and metabolic activity of S. mutans significantly (P < 0.05). S. mutans eDNA and lactic acid production outcomes indicated that Emo-CS-NPs-mediated aPDT led to a significant reduction of eDNA levels (48%) and lactic acid production (72.4%) compared to the control group (P < 0.05). In addition, gtfB mRNA expression in S. mutans was downregulated (7.8-fold) after aPDT in comparison with the control group (P < 0.05).

CONCLUSIONS: Our data support that, aPDT using Emo-CS-NPs revealed the highest cellular uptake and ROS generation. Emo-CS-NPs based aPDT could inhibit significantly biofilm formation and reduce effectively virulence potency of S. mutans; thus, it could be an adjuvant therapy against dental caries.}, } @article {pmid35244796, year = {2022}, author = {Kang, D and Liu, W and Kakahi, FB and Delvigne, F}, title = {Combined utilization of metabolic inhibitors to prevent synergistic multi-species biofilm formation.}, journal = {AMB Express}, volume = {12}, number = {1}, pages = {32}, pmid = {35244796}, issn = {2191-0855}, support = {7988//Walloon Region/ ; }, abstract = {Biofilm is ubiquitous in industrial water systems, causing biofouling and leading to heat transfer efficiency decreases. In particular, multi-species living in biofilms could boost biomass production and enhance treatment resistance. In this study, a total of 37 bacterial strains were isolated from a cooling tower biofilm where acetic acid and propionic acid were detected as the main carbon sources. These isolates mainly belonged to Proteobacteria and Firmicutes, which occupied more than 80% of the total strains according to the 16S rRNA gene amplicon sequencing. Four species (Acinetobacter sp. CTS3, Corynebacterium sp. CTS5, Providencia sp. CTS12, and Pseudomonas sp. CTS17) were observed co-existing in the synthetic medium. Quantitative comparison of biofilm biomass from mono- and multi-species showed a synergistic effect towards biofilm formation among these four species. Three metabolic inhibitors (sulfathiazole, 3-bromopyruvic acid, and 3-nitropropionic acid) were employed to prevent biofilm formation based on their inhibitory effect on corresponding metabolic pathways. All of them displayed evident inhibition profiles to biofilm formation. Notably, combining these three inhibitors possessed a remarkable ability to block the multi-species biofilm development with lower concentrations, suggesting an enhanced effect appeared in simultaneous use. This study demonstrates that combined utilization of metabolic inhibitors is an alternative strategy to prevent multi-species biofilm formation.}, } @article {pmid35243332, year = {2022}, author = {Lin, Y and Briandet, R and Kovács, ÁT}, title = {Bacillus cereus sensu lato biofilm formation and its ecological importance.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100070}, pmid = {35243332}, issn = {2590-2075}, abstract = {Biofilm formation is a ubiquitous process of bacterial communities that enables them to survive and persist in various environmental niches. The Bacillus cereus group includes phenotypically diversified species that are widely distributed in the environment. Often, B. cereus is considered a soil inhabitant, but it is also commonly isolated from plant roots, nematodes, and food products. Biofilms differ in their architecture and developmental processes, reflecting adaptations to specific niches. Importantly, some B. cereus strains are foodborne pathogens responsible for two types of gastrointestinal diseases, diarrhea and emesis, caused by distinct toxins. Thus, the persistency of biofilms is of particular concern for the food industry, and understanding the underlying mechanisms of biofilm formation contributes to cleaning procedures. This review focuses on the genetic background underpinning the regulation of biofilm development, as well as the matrix components associated with biofilms. We also reflect on the correlation between biofilm formation and the development of highly resistant spores. Finally, advances in our understanding of the ecological importance and evolution of biofilm formation in the B. cereus group are discussed.}, } @article {pmid35243252, year = {2022}, author = {Xu, C and Dong, N and Chen, K and Yang, X and Zeng, P and Hou, C and Chi Chan, EW and Yao, X and Chen, S}, title = {Bactericidal, anti-biofilm, and anti-virulence activity of vitamin C against carbapenem-resistant hypervirulent Klebsiella pneumoniae.}, journal = {iScience}, volume = {25}, number = {3}, pages = {103894}, pmid = {35243252}, issn = {2589-0042}, abstract = {The emergence of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) causing high mortality in clinical patients infers the urgent need for developing therapeutic agents. Here, we demonstrated vitamin C (VC) exhibited strong bactericidal, anti-biofilm, and virulence-suppressing effects on CR-hvKP. Our results showed such a bactericidal effect is dose-dependent both in vitro and in the mouse infection model and is associated with induction of reactive oxygen species (ROS) generation. In addition, VC inhibited biofilm formation of CR-hvKP through suppressing the production of exopolysaccharide (EPS). In addition, VC acted as an efflux pump inhibitor at subminimum inhibitory concentration (sub-MIC) to disrupt transportation of EPS and capsular polysaccharide to bacterial cell surface, thereby further inhibiting biofilm and capsule formation. Furthermore, virulence-associated genes in CR-hvKP exposed to sub-MIC of VC were downregulated. Our findings indicated VC could be an effective and safe therapeutic agent to treat CR-hvKP infections in urgent cases when all current treatment options fail.}, } @article {pmid35240893, year = {2022}, author = {Schwarze, J and Koc, J and Koschitzki, F and Gardner, H and Hunsucker, KZ and Swain, GW and Rosenhahn, A}, title = {Reduction of biofilm accumulation by constant and alternating potentials in static and dynamic field experiments.}, journal = {Biofouling}, volume = {38}, number = {2}, pages = {119-130}, doi = {10.1080/08927014.2022.2027923}, pmid = {35240893}, issn = {1029-2454}, mesh = {*Biofilms ; Electric Conductivity ; *Gold ; }, abstract = {The application of electric fields to conductive coatings is an environmentally friendly way to reduce biofilm formation. In particular alternating potentials (APs) have received increasing attention in recent studies. Here, an electrochemical rotating disk setup for dynamic field exposure experiments was developed to study how APs alter the attachment of fouling organisms in a multispecies ocean environment. A specific focus of the device design was proper integration of the potentiostat in the strongly corroding saltwater environment. The effect of APs on the accumulation of fouling organisms in short term field exposures was studied. Potentials on conductive gold surfaces were periodically switched between -0.3 V and 0.3 V or between -0.8 V and 0.6 V at a frequency of 0.5 Hz. APs were capable of significantly reducing the attachment of marine fouling organisms compared with the conductive samples immersed at open circuit potentials.}, } @article {pmid35240424, year = {2022}, author = {Pires, DP and Meneses, L and Brandão, AC and Azeredo, J}, title = {An overview of the current state of phage therapy for the treatment of biofilm-related infections.}, journal = {Current opinion in virology}, volume = {53}, number = {}, pages = {101209}, doi = {10.1016/j.coviro.2022.101209}, pmid = {35240424}, issn = {1879-6265}, mesh = {Bacteria ; *Bacteriophages ; Biofilms ; *Phage Therapy ; }, abstract = {Bacterial biofilms are involved in many chronic and difficult-to-treat infections. Phage therapy against infectious biofilms is becoming a promising strategy, as suggested by the increasing number of publications demonstrating the efficacy of phages against in vitro formed biofilms. However, the translation between in vitro results to in vivo phage therapy outcome is not straightforward due to the complexity of phage-biofilm interactions in clinical contexts. Here, we provide a critical overview of the in vitro studies of phages for biofilm control of clinical pathogens, followed by the major outcomes and lessons learned from the recently reported case studies (between 2018 and 2021) of phage therapy against biofilm-related infections.}, } @article {pmid35240275, year = {2022}, author = {Swain, G and Lal Maurya, K and Kumar Sonwani, R and Sharan Singh, R and Prakash Jaiswal, R and Rai, BN}, title = {Effect of mixing intensity on biodegradation of phenol in a moving bed biofilm reactor: Process optimization and external mass transfer study.}, journal = {Bioresource technology}, volume = {351}, number = {}, pages = {126921}, doi = {10.1016/j.biortech.2022.126921}, pmid = {35240275}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; *Biofilms ; Bioreactors ; Phenol ; *Waste Disposal, Fluid/methods ; }, abstract = {In this work, an effort has been made to design the process variables and to analyse the impact of mixing intensity on mass transfer diffusion in a moving bed biofilm reactor (MBBR). A lab-scale MBBR, filled with Bacillus cereus GS2 IIT (BHU) immobilized-polyethylene biocarriers, was employed to optimize the process variables, including mixing intensity (60-140 rpm), phenol concentration (50-200 mg/L), and hydraulic retention time (HRT) (4-24 h) using response surface methodology. The optimum phenol removal of 87.64 % was found at 100 rpm of mixing intensity, 200 mg/L of phenol concentration, and 24 h of HRT. The higher mixing intensity improved the substrate diffusion between the liquid phase and the surface of the biofilm. The external mass transfer coefficients were found in the range of 1.431 × 10[-5]-1.845 × 10[-5] m/s. Moreover, the detection of catechol and 2-hydroxymuconic semialdehyde revealed that the Bacillus sp. followed the meta-cleavage pathway during the biodegradation of phenol.}, } @article {pmid35239017, year = {2022}, author = {Choudhary, M and Kaushik, S and Kapil, A and Shrivastava, R and Vashistt, J}, title = {Decoding Acinetobacter baumannii biofilm dynamics and associated protein markers: proteomic and bioinformatics approach.}, journal = {Archives of microbiology}, volume = {204}, number = {4}, pages = {200}, pmid = {35239017}, issn = {1432-072X}, support = {YSS/2014/000548//Science and Engineering Research Board/ ; }, mesh = {*Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Computational Biology ; Drug Resistance, Multiple, Bacterial ; Plankton ; Proteomics ; }, abstract = {Biofilm formation by Acinetobacter baumannii is one of the major cause of its persistence in hospital environment. Biofilm phenotypes are more resistant to physical as well as chemical stresses than their planktonic counterparts. The present study was carried in quest of biofilm-associated protein markers and their association with various biological pathways of A. baumannii. The study was designed with an aim to highlight the crucial common factor present in the majority of the A. baumannii strains irrespective of its resistance nature. A label-free proteome comparison of biofilm and planktonic phenotypes of A. baumannii was done using QExactive tandem mass spectrometry. Our investigation suggests key elevation of adhesion factors, acetate metabolism, nutrient transporters, and secretion system proteins are required for biofilm formation in A. baumannii. Elevation of biofilm-associated proteins revealed that biofilm is the unique phenotype with the potential to form robust matrix-embedded colonies and defeat stress condition. Further, core protein markers of biofilm phenotypes could be used as targets for new clinical interventions to combat biofilm-associated infections.}, } @article {pmid35237533, year = {2022}, author = {Leggett, A and Li, DW and Sindeldecker, D and Staats, A and Rigel, N and Bruschweiler-Li, L and Brüschweiler, R and Stoodley, P}, title = {Cadaverine Is a Switch in the Lysine Degradation Pathway in Pseudomonas aeruginosa Biofilm Identified by Untargeted Metabolomics.}, journal = {Frontiers in cellular and infection microbiology}, volume = {12}, number = {}, pages = {833269}, pmid = {35237533}, issn = {2235-2988}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R35 GM139482/GM/NIGMS NIH HHS/United States ; R01 GM066041/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/metabolism ; Biofilms ; Cadaverine ; Humans ; Lysine/metabolism ; Metabolomics ; *Pseudomonas Infections/microbiology ; *Pseudomonas aeruginosa/metabolism ; }, abstract = {There is a critical need to accurately diagnose, prevent, and treat biofilms in humans. The biofilm forming P. aeruginosa bacteria can cause acute and chronic infections, which are difficult to treat due to their ability to evade host defenses along with an inherent antibiotic-tolerance. Using an untargeted NMR-based metabolomics approach, we identified statistically significant differences in 52 metabolites between P. aeruginosa grown in the planktonic and lawn biofilm states. Among them, the metabolites of the cadaverine branch of the lysine degradation pathway were systematically decreased in biofilm. Exogenous supplementation of cadaverine caused significantly increased planktonic growth, decreased biofilm accumulation by 49% and led to altered biofilm morphology, converting to a pellicle biofilm at the air-liquid interface. Our findings show how metabolic pathway differences directly affect the growth mode in P. aeruginosa and could support interventional strategies to control biofilm formation.}, } @article {pmid35234502, year = {2022}, author = {Shang, Y and Guo, J and Zhao, Y and Chen, J and Meng, Q and Qu, D and Zheng, J and Yu, Z and Wu, Y and Deng, Q}, title = {Clemastine Inhibits the Biofilm and Hemolytic of Staphylococcus aureus through the GdpP Protein.}, journal = {Microbiology spectrum}, volume = {10}, number = {2}, pages = {e0054121}, pmid = {35234502}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Clemastine/pharmacology/therapeutic use ; Hemolysis ; Humans ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Oxacillin/pharmacology/therapeutic use ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus ; }, abstract = {Staphylococcus aureus poses a significant threat to human health due to its virulence and multidrug resistance. In addition, recalcitrant biofilm formation of S. aureus often results in chronic infection and the treatment tolerance toward the traditional antibiotics. Thus, the development of novel antimicrobial agents capable to inhibit or eradicate S. aureus biofilm formation does matter. Here, we demonstrated that clemastine showed slight bacteriostatic activity and enhanced the antibacterial activity of oxacillin against S. aureus. Moreover, the dramatic inhibition of biofilm formation was found in clinical S. aureus strains by clemastine. Clemastine inhibited the release of eDNA during the biofilm formation and decreased the S. aureus hemolytic activity. Moreover, the S. aureus SA113 treated with clemastine displayed the decreased transcriptional level of the biofilm formation relevant genes (fnbB, icaA, and icaB), virulence genes (hlg, hld, lukde, lukpvl, beta-PSM, delta-PSM, and cap5A), and the regulatory genes agrA. The proteomics analysis of SA113 treated with clemastine demonstrated the significant changes in levels of biofilm-related proteins (stress response regulators ClpB and GroS, ATP-binding proteins, and urease metabolism), virulence-related proteins (SspA, superantigen, and VWbp), and methicillin resistance-related proteins (glutamine metabolism). The genetic mutations on gdpP (cyclic di-AMP phosphodiesterase) were found in the clemastine-induced tolerant derivative isolate by whole-genome sequencing. Furthermore, the interaction between clemastine and GdpP protein was demonstrated by the molecular docking, gdpP overexpression experiment, and thermal stability assay. Conclusively, clemastine might exert its inhibitory effects against the biofilm formation and hemolysis in S. aureus through targeting GdpP protein. IMPORTANCE The biofilm formation, which protects bacteria from stresses, including antibiotics and host immune responses, can be commonly found in clinical S. aureus isolates worldwide. Treatment failure of traditional antibiotics in biofilm-associated S. aureus infections remains a serious challenge. The novel anti-biofilm drug is urgently needed to address the looming crisis. In this study, clemastine, which is a histamine receptor H1 (HRH1) antagonist, was found to have a novel role of the significant inhibition against the biofilm formation and hemolytic activity of S. aureus and enhanced antibacterial activity against S. aureus when used in combination with oxacillin by targeting the GdpP protein. The discovery of this study identified novel use and mechanism of action of clemastine as a potential anti-biofilm drug for clinical application for S. aureus infectious.}, } @article {pmid35234364, year = {2023}, author = {Condinho, M and Carvalho, B and Cruz, A and Pinto, SN and Arraiano, CM and Pobre, V}, title = {The role of RNA regulators, quorum sensing and c-di-GMP in bacterial biofilm formation.}, journal = {FEBS open bio}, volume = {13}, number = {6}, pages = {975-991}, pmid = {35234364}, issn = {2211-5463}, mesh = {Humans ; *Quorum Sensing/genetics ; *RNA ; Bacterial Proteins/metabolism ; Biofilms ; Bacteria/genetics/metabolism ; }, abstract = {Biofilms provide an ecological advantage against many environmental stressors, such as pH and temperature, making it the most common life-cycle stage for many bacteria. These protective characteristics make eradication of bacterial biofilms challenging. This is especially true in the health sector where biofilm formation on hospital or patient equipment, such as respirators, or catheters, can quickly become a source of anti-microbial resistant strains. Biofilms are complex structures encased in a self-produced polymeric matrix containing numerous components such as polysaccharides, proteins, signalling molecules, extracellular DNA and extracellular RNA. Biofilm formation is tightly controlled by several regulators, including quorum sensing (QS), cyclic diguanylate (c-di-GMP) and small non-coding RNAs (sRNAs). These three regulators in particular are fundamental in all stages of biofilm formation; in addition, their pathways overlap, and the significance of their role is strain-dependent. Currently, ribonucleases are also of interest for their potential role as biofilm regulators, and their relationships with QS, c-di-GMP and sRNAs have been investigated. This review article will focus on these four biofilm regulators (ribonucleases, QS, c-di-GMP and sRNAs) and the relationships between them.}, } @article {pmid35234019, year = {2022}, author = {Hemeg, HA}, title = {Combatting persisted and biofilm antimicrobial resistant bacterial by using nanoparticles.}, journal = {Zeitschrift fur Naturforschung. C, Journal of biosciences}, volume = {77}, number = {9-10}, pages = {365-378}, doi = {10.1515/znc-2021-0296}, pmid = {35234019}, issn = {1865-7125}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Bacteria ; *Biofilms ; *Nanoparticles ; }, abstract = {Some bacteria can withstand the existence of an antibiotic without undergoing any genetic changes. They are neither cysts nor spores and are one of the causes of disease recurrence, accounting for about 1% of the biofilm. There are numerous approaches to eradication and combating biofilm-forming organisms. Nanotechnology is one of them, and it has shown promising results against persister cells. In the review, we go over the persister cell and biofilm in extensive detail. This includes the biofilm formation cycle, antibiotic resistance, and treatment with various nanoparticles. Furthermore, the gene-level mechanism of persister cell formation and its therapeutic interventions with nanoparticles were discussed.}, } @article {pmid35229647, year = {2022}, author = {Liu, M and Nie, H and Luo, X and Yang, S and Chen, H and Cai, P}, title = {A Polysaccharide Biosynthesis Locus in Vibrio parahaemolyticus Important for Biofilm Formation Has Homologs Widely Distributed in Aquatic Bacteria Mainly from Gammaproteobacteria.}, journal = {mSystems}, volume = {7}, number = {2}, pages = {e0122621}, pmid = {35229647}, issn = {2379-5077}, mesh = {*Vibrio parahaemolyticus/genetics ; *Gammaproteobacteria ; Biofilms ; Quorum Sensing ; }, abstract = {Vibrio parahaemolyticus is a seafood-borne pathogen that poses a great threat to public health worldwide. It is found in either a planktonic cell or a biofilm form in the natural environment. The cps locus has been the only extensively studied polysaccharide biosynthesis gene cluster involved in biofilm formation for this bacterium. In this study, we found that an additional polysaccharide biosynthesis locus, scv, is also necessary for biofilm maturation. The scv locus is composed of two operons, and a loss of their expression leads to a defective biofilm phenotype. The transcription of the scv locus is under the control of a sigma 54-dependent response regulator, ScvE. In contrast, the quorum-sensing regulator AphA stimulates the expression of the cps locus and the scvABCD operon found in the scv locus. Bioinformatic analyses demonstrated that scv loci are divergent and widely distributed among 28 genera, including 26 belonging to the Gammaproteobacteria and 2 within the Alphaproteobacteria. We also determined that all scv locus-positive species are water-dwelling. Some strains of Aeromonas, Aliivibrio salmonicida, Pseudomonas anguilliseptica, Vibrio breoganii, and Vibrio scophthalmi probably acquired scv loci through insertion sequences and/or integrase-mediated horizontal gene transfer. Gene duplication and fusion were also detected in some scv homologs. Together, our results suggest that the genome of V. parahaemolyticus harbors two distinct polysaccharide biosynthesis loci, which may play a role in fine-tuning biofilm development, and that scv loci likely evolved by horizontal gene transfer, gene loss, gene duplication, and fragment fusion. IMPORTANCE Polysaccharides are the major component of biofilms, which provide survival advantages for bacteria in aquatic environments. The seafood-borne pathogen V. parahaemolyticus possesses a functionally uncharacterized polysaccharide biosynthesis locus, scv. We demonstrated that the scv locus is important for biofilm maturation and that scv expression is positively regulated by ScvE. Strains from 148 aquatic bacterial species possess scv homolog loci. These bacterial species belong to 28 genera, most of which belong to the Gammaproteobacteria class. The evolution and diversification of scv loci are likely driven by horizontal gene transfer, gene loss, gene duplication, and fragment fusion. Our results provide new insights into the function and evolution of this widespread polysaccharide biosynthesis locus.}, } @article {pmid35227677, year = {2022}, author = {Anh-Vu, N and Yun-Je, L and Masumi, K and Visvanathan, C}, title = {Effects of membrane relaxation rate on performance of pilot-scale membrane aerated biofilm reactors treating domestic wastewater.}, journal = {Environmental research}, volume = {211}, number = {}, pages = {113003}, doi = {10.1016/j.envres.2022.113003}, pmid = {35227677}, issn = {1096-0953}, mesh = {Biofilms ; Bioreactors/microbiology ; Nitrogen ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The membranes of a Membrane Aerated Biofilm Reactor (MABR) function as bubble-less air diffusers and bio-carriers. Recent bench-scale experiments reported that the shape of membranes influenced the oxygen transfer and utilization rates, which in turn affected the pollutant removal performance of the MABR. In this study, two pilot-scale MABRs using multi-layer hollow fiber membranes with the relaxation rates of 0.1-1.8% (MABR 1) and 1.0-2.8% (MABR 2) were used for the treatment of organics and nitrogen in real medium-strength domestic wastewater. Higher-relaxation-rate membranes have loose and more curved fiber bunch that may allow biofilm to grow more easily and let air diffuse more efficiently. MABR 2 had achieved better performance than MABR 1 at 12- and 6-h Hydraulic Retention Time (HRT), with respectively 0.7-4.3%, 17.7-18.1%, and 5.5-9.0% higher removal efficiencies for Chemical Oxygen Demand (COD), Ammonia Nitrogen (NH4[+]), and Total Nitrogen (TN). The highest COD, NH4[+], and TN removal efficiencies were 94.7%, 81.1%, and 57.1%, respectively, at 12 h HRT in MABR 2. The addition of Polyvinyl Alcohol (PVA) gel beads carrying denitrifying bacteria had enhanced the denitrification in both the reactors. Increments of 5.0-9.0% and 6.6-12.3% were reported for TN removal efficiencies of MABR 1 and 2 combined with PVA gel, sequentially.}, } @article {pmid35227378, year = {2022}, author = {Tajani, AS and Soheili, V and Moosavi, F and Ghodsi, R and Alizadeh, T and Fazly Bazzaz, BS}, title = {Ultra selective and high-capacity dummy template molecular imprinted polymer to control quorum sensing and biofilm formation of Pseudomonas aeruginosa.}, journal = {Analytica chimica acta}, volume = {1199}, number = {}, pages = {339574}, doi = {10.1016/j.aca.2022.339574}, pmid = {35227378}, issn = {1873-4324}, mesh = {Biofilms ; *Molecular Imprinting/methods ; Polymers/chemistry ; Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {Here a highly selective molecular imprinting polymer was developed to attenuate biofilm formation of the multidrug-resistant pathogen Pseudomonas aeruginosa by disrupting the intermolecular signaling system. Firstly, a dummy template molecular imprinting polymer (MIP) was rationally designed through molecular modeling to capture 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas quinolone signal). This multifunctional signaling molecule interferes with the pathogenicity of P. aeruginosa as an auto-inducer. Then, the synthesized MIP and the non-imprinted polymer (NIP) as reference polymer were evaluated for their binding capacity and biofilm inhibition. The results indicated a significant difference in biofilm inhibition (∼56%) between imprinted (∼67%) and non-imprinted (∼11%) polymer, which is an impressive level, especially for the treatment of various surfaces affected by P. aeruginosa. These results open a new window in the special biological application of MIPs as a promising candidate to reduce concerns in clinical or industrial issues by preventing microbial infections.}, } @article {pmid35227160, year = {2022}, author = {Chattopadhyay, I and J, RB and Usman, TMM and Varjani, S}, title = {Exploring the role of microbial biofilm for industrial effluents treatment.}, journal = {Bioengineered}, volume = {13}, number = {3}, pages = {6420-6440}, pmid = {35227160}, issn = {2165-5987}, mesh = {*Biodegradation, Environmental ; *Biofilms ; CRISPR-Cas Systems ; Gene Editing ; Genome, Bacterial/genetics ; *Industrial Waste ; *Quorum Sensing ; *Wastewater ; }, abstract = {Biofilm formation on biotic or abiotic surfaces is caused by microbial cells of a single or heterogeneous species. Biofilm protects microbes from stressful environmental conditions, toxic action of chemicals, and antimicrobial substances. Quorum sensing (QS) is the generation of autoinducers (AIs) by bacteria in a biofilm to communicate with one other. QS is responsible for the growth of biofilm, synthesis of exopolysaccharides (EPS), and bioremediation of environmental pollutants. EPS is used for wastewater treatment due to its three-dimensional matrix which is composed of proteins, polysaccharides, humic-like substances, and nucleic acids. Autoinducers mediate significantly the degradation of environmental pollutants. Acyl-homoserine lactone (AHL) producing bacteria as well as quorum quenching enzyme or bacteria can effectively improve the performance of wastewater treatment. Biofilms-based reactors due to their economic and ecofriendly nature are used for the treatment of industrial wastewaters. Electrodes coated with electro-active biofilm (EAB) which are obtained from sewage sludge, activated sludge, or industrial and domestic effluents are getting popularity in bioremediation. Microbial fuel cells are involved in wastewater treatment and production of energy from wastewater. Synthetic biological systems such as genome editing by CRISPR-Cas can be used for the advanced bioremediation process through modification of metabolic pathways in quorum sensing within microbial communities. This narrative review discusses the impacts of QS regulatory approaches on biofilm formation, extracellular polymeric substance synthesis, and role of microbial community in bioremediation of pollutants from industrial effluents.}, } @article {pmid35224441, year = {2021}, author = {Ivory, JD and Vellinga, A and O'Gara, J and Gethin, G}, title = {A scoping review protocol to identify clinical signs, symptoms and biomarkers indicative of biofilm presence in chronic wounds.}, journal = {HRB open research}, volume = {4}, number = {}, pages = {71}, pmid = {35224441}, issn = {2515-4826}, abstract = {Introduction: Wound healing is characterised by haemostatic, inflammatory, proliferative and remodelling phases. In the presence of comorbidities such as diabetes, healing can stall and chronic wounds may result. Infection is detrimental to these wounds and associated with poor outcomes. Wounds are contaminated with microbes and debris, and factors such as host resistance, bacterial virulence, species synergy and bioburden determine whether a wound will deteriorate to critically colonised/infected states. Biofilms are sessile microbial communities, exhibiting high-level antibiotic tolerance and resistance to host defences. Biofilm in critically colonised wounds can contribute to delayed healing. Little is known about clinical presentation and diagnosis of wound biofilms. Objective: To identify from the literature clinical signs, symptoms and biomarkers that may indicate biofilm presence in chronic wounds. Methods: This review will be guided by the Preferred Reporting Items for Systematic Reviews extension for Scoping Reviews (PRISMA-ScR), and the Joanna Briggs Institute Manual for Evidence Synthesis. Studies of any design in any language recruiting adult patients with venous, diabetic, pressure or mixed arterial-venous ulcers and reporting data on clinical signs/symptoms of biofilm are eligible. Searches of Medline, Embase, CINAHL, Cochrane Central and BASE will be conducted from inception to present. Reference scanning and contact with content experts will be employed. Title/abstract screening and full text selection will be executed by two reviewers independently. Discrepancies will be resolved by discussion between reviewers or through third party intervention. Data will be extracted by a single reviewer and verified by a second. Clinical signs and symptoms data will be presented in terms of study design, setting and participant demographic data. Discussion: Understanding biofilm impact on chronic wounds is inconsistent and based largely on in vitro research. This work will consolidate clinical signs, symptoms and biomarkers of biofilm in chronic wounds reported in the literature.}, } @article {pmid35224308, year = {2022}, author = {Yu, Y and Zhang, Y and Cheng, Y and Wang, Y and Chen, Z and Sun, H and Wei, X and Ma, Z and Li, J and Bai, Y and Wu, Z and Zhang, X}, title = {NIR-activated nanosystems with self-modulated bacteria targeting for enhanced biofilm eradication and caries prevention.}, journal = {Bioactive materials}, volume = {13}, number = {}, pages = {269-285}, pmid = {35224308}, issn = {2452-199X}, abstract = {The efficacious delivery of antimicrobial drugs to intractable oral biofilms remains a challenge due to inadequate biofilm penetration and lack of pathogen targeting. Herein, we have developed a microenvironment-activated poly(ethylene glycol) (PEG)-sheddable nanoplatform to mediate targeted delivery of drugs into oral biofilms for the efficient prevention of dental caries. The PEGylated nanoplatform with enhanced biofilm penetration is capable of deshielding the PEG layer under slightly acidic conditions in a PEG chain length-dependent manner to re-expose the bacteria-targeting ligands, thereby facilitating targeted codelivery of ciprofloxacin (CIP) and IR780 to the bacteria after accumulation within biofilms. The nanoplatform tends to induce bacterial agglomeration and suffers from degradation in the acidic oral biofilm microenvironment, triggering rapid drug release on demand around bacterial cells. The self-modulating nanoplatform under near-infrared (NIR) irradiation accordingly displays greatly augmented potency in oral biofilm penetration and disruption compared with drugs alone. Topical oral treatment with nanoplatforms involving synergetic pharmacological and photothermal/photodynamic trinary therapy results in robust biofilm dispersion and efficacious suppression of severe tooth decay in rats. This versatile nanoplatform can promote local accumulation and specific drug transport into biofilms and represents a new paradigm for targeted drug delivery for the management of oral biofilm-associated infections.}, } @article {pmid35222868, year = {2021}, author = {Scheeren Brum, R and Apaza-Bedoya, K and Labes, LG and Volpato, CÂM and Pimenta, AL and Benfatti, CAM}, title = {Early Biofilm Formation on Rough and Smooth Titanium Specimens: a Systematic Review of Clinical Studies.}, journal = {Journal of oral & maxillofacial research}, volume = {12}, number = {4}, pages = {e1}, pmid = {35222868}, issn = {2029-283X}, abstract = {OBJECTIVES: There is a concern whether the enhancement on implant surface roughness is responsible for higher biofilm formation, which acts as an aetiological factor for peri-implant diseases. The aim of the present systematic review was to answer the following question: "Are rough surfaces more susceptible to early biofilm formation when compared to smoother surfaces on titanium specimens?".

MATERIAL AND METHODS: The research was performed on PubMed, Web of Science and Scopus, up to August 2021. Eligibility criteria included studies that analysed human biofilm formation on titanium specimens with distinct surface roughness (smooth vs minimally, moderate, or rough) over the experimental times of 1 or 3 days. Roughness average (Ra) and biofilm analysis parameters were extracted from selected articles. Risk of bias was evaluated using the Checklist for Quasi-Experimental Studies.

RESULTS: Of 5286 papers, 5 were included and analysed. Smooth titanium surfaces included machined and anodized titanium/Ti-6Al-4V; machined and acid etched TiZr. Minimally, moderately, or rough surfaces comprised titanium and titanium alloys (TiZr, Ti-6Al-4V), that received surface treatments (anodization, acid-etching, blasting, hydroxyapatite-coating). No statistically significant difference on biofilm formation on rough and smooth titanium surfaces was reported by 3 studies, while more contamination on rough titanium surfaces was stated by 2 investigations. An isolated smooth surface has also been associated to higher contamination. Moderate to high quality methodological assessment of studies were identified.

CONCLUSIONS: It is not possible to assume that rough surfaces are more susceptible to early biofilm formation than smooth titanium surfaces. Additional studies are required to study this multifarious interaction.}, } @article {pmid35222859, year = {2021}, author = {Davarzani, F and Yousefpour, Z and Saidi, N and Owlia, P}, title = {Different effects of sub-minimum inhibitory concentrations of gentamicin on the expression of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa.}, journal = {Iranian journal of microbiology}, volume = {13}, number = {6}, pages = {808-816}, pmid = {35222859}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Antibiotics at sub-minimum inhibitory concentrations (sub-MIC) may alter bacterial virulence factors. The objective of this study was to investigate the effect of gentamicin at sub-MIC concentrations on the expression of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa.

MATERIALS AND METHODS: The broth microdilution method was used to determine the MIC of gentamicin for three P. aeruginosa clinical isolates (P1-P3) and standard strains (PAO1 and 8821M). Alginate production and biofilm formation of the bacteria in the presence and absence of sub-MIC concentrations of gentamicin were measured using microtiter plate and carbazole assay, respectively. The real-time PCR method was used to determine the effect of gentamicin at sub-MIC concentrations on the expression level of genes involved in biofilm formation (pelA and pslA) and alginate production (algD and algU).

RESULTS: Gentamicin at sub-MIC concentrations significantly reduced alginate production, biofilm formation, and the expression of alginate and biofilm-encoding genes in clinical isolate P1. This inhibitory effect was also observed on the alginate production of 8821M strain and biofilm formation of PAO1strain. In clinical isolates, P2 and P3, alginate production, biofilm formation, and the expression of alginate and biofilm-encoding genes were significantly increased in exposure to sub-MIC concentrations of gentamicin.

CONCLUSION: This study showed that different phenotypic changes in clinical isolates and standard strains of P. aeruginosa in exposure to sub-MIC concentrations of gentamicin are associated with changes in the expression of virulence genes. Further researches are required to understand the mechanisms involved in regulating the expression of virulence genes after exposure to sub-MIC concentrations of antibiotics.}, } @article {pmid35222316, year = {2021}, author = {Carbonero-Pacheco, J and Moreno-García, J and Moreno, J and García-Martínez, T and Mauricio, JC}, title = {Revealing the Yeast Diversity of the Flor Biofilm Microbiota in Sherry Wines Through Internal Transcribed Spacer-Metabarcoding and Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {825756}, pmid = {35222316}, issn = {1664-302X}, abstract = {Flor yeast velum is a biofilm formed by certain yeast strains that distinguishes biologically aged wines such as Sherry wine from southern Spain from others. Although Saccharomyces cerevisiae is the most common species, 5.8 S-internal transcribed spacer (ITS) restriction fragment length polymorphism analyses have revealed the existence of non-Saccharomyces species. In order to uncover the flor microbiota diversity at a species level, we used ITS (internal transcribed spacer 1)-metabarcoding and matrix-assisted laser desorption/Ionization time of flight mass spectrometry techniques. Further, to enhance identification effectiveness, we performed an additional incubation stage in 1:1 wine:yeast extract peptone dextrose (YPD) before identification. Six species were identified: S. cerevisiae, Pichia manshurica, Pichia membranifaciens, Wickerhamomyces anomalus, Candida guillermondii, and Trichosporon asahii, two of which were discovered for the first time (C. guillermondii and Trichosporon ashaii) in Sherry wines. We analyzed wines where non-Saccharomyces yeasts were present or absent to see any potential link between the microbiota and the chemical profile. Only 2 significant volatile chemicals (out of 13 quantified), ethanol and ethyl lactate, and 2 enological parameters (out of 6 quantified), such as pH and titratable acidity, were found to differ in long-aged wines. Although results show a low impact where the non-Saccharomyces yeasts are present, these yeasts isolated from harsh environments (high ethanol and low nutrient availability) could have a potential industrial interest in fields such as food microbiology and biofuel production.}, } @article {pmid35220101, year = {2022}, author = {Borges, ADV and Fuess, LT and Takeda, PY and Alves, I and Dias, MES and Damianovic, MHRZ}, title = {Co-digestion of biofuel by-products: Enhanced biofilm formation maintains high organic matter removal when methanogenesis fails.}, journal = {Journal of environmental management}, volume = {310}, number = {}, pages = {114768}, doi = {10.1016/j.jenvman.2022.114768}, pmid = {35220101}, issn = {1095-8630}, mesh = {Anaerobiosis ; Biofilms ; *Biofuels ; *Bioreactors ; Digestion ; Methane ; }, abstract = {Ethanol and biodiesel industries generate large volumes of by-products, such as vinasse and glycerol, which are suitable for biogas exploitation. This paper assessed the applicability and process performance of the anaerobic structured-bed reactor (AnSTBR) for the mesophilic (30 °C) continuous (105 days) anaerobic co-digestion of sugarcane vinasse and distilled glycerol under increasing organic loading rates (OLR) (0.5-5.0 kgCOD m[-3]d[-1]). The highest methane yield (211 NmL g[-1]CODrem.) and volumetric production (668 NmL L[-1]d[-1]) occurred at an OLR of 3.5 kgCOD m[-3]d[-1]. The performance of the AnSTBR showed high removal efficiencies of total COD (77.1%), carbohydrates (81.9%), and glycerol content (99.7%). Biofilm growth enhancement within the reactor offset the impairment of methanogenesis activity at high organic loads. The prompt biodegradability of glycerol reinforced the importance of gradually increase the organic load to prevent the buildup of volatile acids and maintain a stable long-term co-digestion system.}, } @article {pmid35219669, year = {2022}, author = {de Celis, M and Belda, I and Marquina, D and Santos, A}, title = {Phenotypic and transcriptional study of the antimicrobial activity of silver and zinc oxide nanoparticles on a wastewater biofilm-forming Pseudomonas aeruginosa strain.}, journal = {The Science of the total environment}, volume = {826}, number = {}, pages = {153915}, doi = {10.1016/j.scitotenv.2022.153915}, pmid = {35219669}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents/pharmacology/toxicity ; Biofilms/drug effects ; Iron ; Metal Nanoparticles/toxicity ; *Nanoparticles/toxicity ; Pseudomonas aeruginosa/drug effects ; Reactive Oxygen Species ; *Silver/toxicity ; Wastewater/toxicity ; *Zinc Oxide/toxicity ; }, abstract = {The extensive use of nanoparticles (NPs) in industrial processes makes their potential release into the environment an issue of concern. Ag and ZnO NPs are among the most frequently used NPs, potentially reaching concentrations of 1-4 and 64 mg/kg, respectively, in Wastewater Treatment Plants (WWTPs), with unknown effects over microbial populations. Thus, we examined, in depth, the effect of such NPs on a P. aeruginosa strain isolated from a WWTP. We evaluated the growth, ROS production and biofilm formation, in addition to the transcriptomic response in presence of Ag and ZnO NPs at concentrations potentially found in sewage sludge. The transcriptomic and phenotypic patterns of P. aeruginosa in presence of Ag NPs were, in general, similar to the control treatment, with some specific transcriptional impacts affecting processes involved in biofilm formation and iron homeostasis. The biofilms formed under Ag NPs treatment were, on average, thinner and more homogeneous. ZnO NPs also alters the biofilm formation and iron homeostasis in P. aeruginosa, however, the higher and more toxic concentrations utilized caused an increase in cell death and eDNA release. Thus, the biofilm development was characterized by EPS production, via eDNA release. The number of differentially expressed genes in presence of ZnO NPs was higher compared to Ag NPs treatment. Even though the responses of P. aeruginosa to the presence of the studied metallic NPs was at some extent similar, the higher and more toxic concentrations of ZnO NPs produced greater changes concerning cell viability and ROS production, causing disruption in biofilm development.}, } @article {pmid35217675, year = {2022}, author = {Corsini, PM and Wang, S and Rehman, S and Fenn, K and Sagar, A and Sirovica, S and Cleaver, L and Edwards-Gayle, CJC and Mastroianni, G and Dorgan, B and Sewell, LM and Lynham, S and Iuga, D and Franks, WT and Jarvis, J and Carpenter, GH and Curtis, MA and Bernadó, P and Darbari, VC and Garnett, JA}, title = {Molecular and cellular insight into Escherichia coli SslE and its role during biofilm maturation.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {9}, pmid = {35217675}, issn = {2055-5008}, support = {SBF002/1150/WT_/Wellcome Trust/United Kingdom ; 202767/Z/16/Z//Wellcome Trust (Wellcome)/ ; FC001029/WT_/Wellcome Trust/United Kingdom ; MR/R017662/1/MRC_/Medical Research Council/United Kingdom ; FC001029/CRUK_/Cancer Research UK/United Kingdom ; MC_U117533887/MRC_/Medical Research Council/United Kingdom ; FC001029/ARC_/Arthritis Research UK/United Kingdom ; IG/16/2/32273//British Heart Foundation (BHF)/ ; /WT_/Wellcome Trust/United Kingdom ; IG/16/2/32273/BHF_/British Heart Foundation/United Kingdom ; }, mesh = {Biofilms ; Escherichia coli/physiology ; *Escherichia coli Infections/microbiology ; *Escherichia coli Proteins/genetics/metabolism ; Humans ; Intestines ; }, abstract = {Escherichia coli is a Gram-negative bacterium that colonises the human intestine and virulent strains can cause severe diarrhoeal and extraintestinal diseases. The protein SslE is secreted by a range of pathogenic and commensal E. coli strains. It can degrade mucins in the intestine, promotes biofilm maturation and it is a major determinant of infection in virulent strains, although how it carries out these functions is not well understood. Here, we examine SslE from the commensal E. coli Waksman and BL21 (DE3) strains and the enterotoxigenic H10407 and enteropathogenic E2348/69 strains. We reveal that SslE has a unique and dynamic structure in solution and in response to acidification within mature biofilms it can form a unique aggregate with amyloid-like properties. Furthermore, we show that both SslE monomers and aggregates bind DNA in vitro and co-localise with extracellular DNA (eDNA) in mature biofilms, and SslE aggregates may also associate with cellulose under certain conditions. Our results suggest that interactions between SslE and eDNA are important for biofilm maturation in many E. coli strains and SslE may also be a factor that drives biofilm formation in other SslE-secreting bacteria.}, } @article {pmid35216986, year = {2022}, author = {Fan, Y and Zhang, M and Cheng, J and Yong, D and Ji, J and Wu, Q and He, C}, title = {Elucidating nitrifying performance, nitrite accumulation and microbial community in a three-stage plug flow moving bed biofilm reactor (PF - MBBR).}, journal = {Chemosphere}, volume = {297}, number = {}, pages = {134087}, doi = {10.1016/j.chemosphere.2022.134087}, pmid = {35216986}, issn = {1879-1298}, mesh = {Ammonia ; Bacteria ; Biofilms ; Bioreactors/microbiology ; *Microbiota ; Nitrification ; *Nitrites ; Nitrogen ; Wastewater ; }, abstract = {A three-stage plug flow moving bed biofilm reactor (PF - MBBR, consisting of three identical chambers of N1, N2 and N3) was proposed for nitrifier enrichment using synthetic wastewater. During the stable operation, the average NH4[+]-N effluent was 0.67 mg/L and NH4[+]-N removal was as high as 97.19% with the nitrite accumulation ratio (NAR) of 54.23%, although the biofilm thickness and biomass both presented downward trends from N1 (296 μm, 2280 mg/L), N2 (248 μm, 1850 mg/L) to N3 (198 μm, 1545 mg/L). Particularly, the comparative results of three stages revealed that N2 showed the optimum NH4[+]-N removal (77.27%) and NAR (75.21%) in the continuous-flow, while NAR of N3 unexpectedly maintained a high level of 65.83% in the batch test, suggesting that ammonia oxidizing bacteria (AOB) accounted for absolute advantage over nitrite oxidizing bacteria (NOB). High-throughput sequencing initially verified different distribution of bacterial community structure, where N2 was far away from N1 and N3 with the lowest community richness and community diversity (operational taxonomic units (OTUs): 454(N2)<527(N3)<621(N1)). Proteobacteria (77.60%-83.09%), Bacteroidetes (1.66%-3.66%), Acidobacteria (2.28%-4.67%), and Planctomycetes (1.19%-6.63%) were the major phyla. At the genus level, AOB (mainly Nitrosomonas) accounted for 5.08% (N1), 20.74% (N2) and 14.24% (N3) while NOB (mainly Nitrospira) increased from 0.14% (N1), 7.06% (N2) to 4.91% (N3) with the total percentages of 5.22%, 27.80% and 19.15%. Finally, the application feasibility of MBBR optimization linked with nitrite (NO2[-]-N) accumulation for deep-level nutrient removal was discussed.}, } @article {pmid35216827, year = {2022}, author = {Kong, X and Li, C and Sun, X and Niu, B and Guo, D and Jiang, Y and Yang, J and Chen, Q}, title = {The maltose transporter subunit IICB of the phosphotransferase system: An important factor for biofilm formation of Cronobacter.}, journal = {International journal of food microbiology}, volume = {370}, number = {}, pages = {109517}, doi = {10.1016/j.ijfoodmicro.2021.109517}, pmid = {35216827}, issn = {1879-3460}, mesh = {Biofilms ; *Cronobacter/genetics ; *Cronobacter sakazakii/genetics ; Maltose/metabolism ; Phosphotransferases/metabolism ; }, abstract = {Cronobacter is a common food-borne opportunistic pathogen, which is easily to form biofilm and difficult to remove. The regulation mechanism on the biofilm formation of Cronobacter has drawn more and more attention. In here, transcriptomic sequencing of free and biofilm states of Cronobacter was performed, and analyzed to identify the differential gene expression through Gene Ontology (GO) function, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Based on sequencing analysis of the results, the malX gene encoding maltose transporter subunit IICB in the phosphotransferase system (PTS) might be involved in the formation of Cronobacter biofilm and thus selected for gene knockout. Hereafter, the changes in biofilm formation ability, extracellular polymer and biofilm-related gene expression of malX gene knockout strains were detected to explore the potential mechanism of malX gene on biofilm formation of Cronobacter. From the result, weaken biofilm formation ability of Cronobacter, decreased extracellular polysaccharide content and down-regulated expression of cellulose-related genes were obtained after knockout of malX gene, which verified our deduction. This study is the first to elucidates the regulation mechanism of the PTS on the biofilm formation of Cronobacter, which lays a foundation for the further prevention and control of food contamination caused by Cronobacter.}, } @article {pmid35215592, year = {2022}, author = {Marín-Sanhueza, C and Echeverría-Vega, A and Gómez, A and Cabrera-Barjas, G and Romero, R and Banerjee, A}, title = {Stress Dependent Biofilm Formation and Bioactive Melanin Pigment Production by a Thermophilic Bacillus Species from Chilean Hot Spring.}, journal = {Polymers}, volume = {14}, number = {4}, pages = {}, pmid = {35215592}, issn = {2073-4360}, abstract = {Thermophilic bacteria able to survive extreme temperature stress are of great biotechnological interest due to their extracellular production of bioactive molecules as a part of a survival strategy, or by intracellular modifications. In the present study, thermophilic Bacillus haynesii CamB6, isolated from a Chilean hot spring, was studied for the formation of different stress response molecules. The polymeric pigment produced by the bacterial strain was characterized by different physicochemical techniques. On exposure to ranges of temperature (50-60 °C), pH (5.0-7.0), and sources of nitrogen and carbon (1-5 g·L[-1]), the bacteria responded with a biofilm network formation in a hydrophobic polystyrene surface. Biofilm formation under fed-batch conditions was also statistically validated. The bacteria showed a planktonic pellicle network formation in the presence of induced hypoxia and salinity stress (19.45 g·L[-1]) under static conditions. Salinity stress also resulted in the intracellular response of brown pigment production. The pigment was structurally and functionally characterized by UV-Vis absorbance and the presence of different characteristic peaks via FTIR analysis (bacterial pyomelanin fingerprints) were assessed. A high thermal stability and TGA profile indicated the brown pigment was a probable pyomelanin candidate. Micropyrolysis (Py-GC/MS) showed that isoprene, pyrrole, benzene, pyridine, and their derivatives were the major components detected. In addition, acetic acid, indole, phenol, and its derivatives were observed. The absence of sulfocompounds in the pyrolyzed products agreed with those reported in the literature for pyomelanin. The pigment surface morphology was analyzed via SEM, and the elemental composition via EDS also demonstrated the similarity of the brown pigment to that of the melanin family. The pyomelanin pigment was observed to be bioactive with promising antioxidant capacity (H2O2, Fe[2+]) compared to the standard antioxidant molecules. In conclusion, B. haynesii CamB6 demonstrated the formation of several biomolecules as a stress response mechanism that is bioactive, showing its probable biotechnological applications in future.}, } @article {pmid35215373, year = {2022}, author = {Bosso, A and Gaglione, R and Di Girolamo, R and Veldhuizen, EJA and García-Vello, P and Fusco, S and Cafaro, V and Monticelli, M and Culurciello, R and Notomista, E and Arciello, A and Pizzo, E}, title = {Human Cryptic Host Defence Peptide GVF27 Exhibits Anti-Infective Properties against Biofilm Forming Members of the Burkholderia cepacia Complex.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {15}, number = {2}, pages = {}, pmid = {35215373}, issn = {1424-8247}, support = {FFC 16/2017; FFC 18/2018//Italian Cystic Fibrosis Foundation/ ; }, abstract = {Therapeutic solutions to counter Burkholderia cepacia complex (Bcc) bacteria are challenging due to their intrinsically high level of antibiotic resistance. Bcc organisms display a variety of potential virulence factors, have a distinct lipopolysaccharide naturally implicated in antimicrobial resistance. and are able to form biofilms, which may further protect them from both host defence peptides (HDPs) and antibiotics. Here, we report the promising anti-biofilm and immunomodulatory activities of human HDP GVF27 on two of the most clinically relevant Bcc members, Burkholderia multivorans and Burkholderia cenocepacia. The effects of synthetic and labelled GVF27 were tested on B. cenocepacia and B. multivorans biofilms, at three different stages of formation, by confocal laser scanning microscopy (CLSM). Assays on bacterial cultures and on human monocytes challenged with B. cenocepacia LPS were also performed. GVF27 exerts, at different stages of formation, anti-biofilm effects towards both Bcc strains, a significant propensity to function in combination with ciprofloxacin, a relevant affinity for LPSs isolated from B. cenocepacia as well as a good propensity to mitigate the release of pro-inflammatory cytokines in human cells pre-treated with the same endotoxin. Overall, all these findings contribute to the elucidation of the main features that a good therapeutic agent directed against these extremely leathery biofilm-forming bacteria should possess.}, } @article {pmid35215091, year = {2022}, author = {Dawan, J and Li, Y and Lu, F and He, X and Ahn, J}, title = {Role of Efflux Pump-Mediated Antibiotic Resistance in Quorum Sensing-Regulated Biofilm Formation by Salmonella Typhimurium.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {2}, pages = {}, pmid = {35215091}, issn = {2076-0817}, support = {NRF-2016R1D1A3B01008304//National Research Foundation of Korea/ ; }, abstract = {This study was designed to assess the influence of efflux pump activity on the biofilm formation in Salmonella Typhimurium. Salmonella enterica subsp. enterica serovar Typhimurium ATCC 19585 (ST[WT]) and clinically isolated S. Typhimurium CCARM 8009 (ST[CI]) were treated with ceftriaxone (CEF), chloramphenicol (CHL), ciprofloxacin (CIP), erythromycin (ERY), norfloxacin (NOR), and tetracycline (TET) in autoinducer-containing media in the absence and presence of phenylalanine-arginine β-naphthylamide (PAβN) to compare efflux pump activity with biofilm-forming ability. The susceptibilities of ST[WT] and ST[CI] were increased in the presence of PAβN. ERY+PAβN showed the highest decrease in the minimum inhibitory concentration (MIC) of ERY from 256 to 2 μg/mL against ST[WT] and ST[CI]. The antimicrobial activity of NOR against planktonic cells was significantly increased in the presence of PAβN, showing the lowest numbers of ST[WT] (3.2 log CFU/cm[2]), and the TET+PAβN effectively inhibited the growth of ST[CI] (5.2 log CFU/cm[2]). The lowest biofilm-forming abilities were observed at NOR+PAβN against ST[WT] (biofilm-forming index, BFI < 0.41) and CEF+PAβN against ST[CI] (BFI = 0.32). The bacteria swimming motility and relative fitness varied depending on the antibiotic and PAβN treatments. The motility diameters of ST[WT] were significantly decreased by NOR+PAβN (6 mm) and TET+PAβN (15 mm), while the lowest motility of ST[CI] was observed at CIP+PAβN (8 mm). The significant decrease in the relative fitness levels of ST[WT] and ST[CI] was observed at CIP+PAβN and NOR+PAβN. The PAβN as an efflux pump inhibitor (EPI) can improve the antimicrobial and anti-biofilm efficacy of antibiotics against S. Typhimurium. This study provides useful information for understanding the role of efflux pump activity in quorum sensing-regulated biofilm formation and also emphasizes the necessity of the discovery of novel EPIs for controlling biofilm formation by antibiotic-resistant pathogens.}, } @article {pmid35214928, year = {2022}, author = {Abdal, S and Siddique, I and Afzal, S and Sharifi, S and Salimi, M and Ahmadian, A}, title = {An Analysis for Variable Physical Properties Involved in the Nano-Biofilm Transportation of Sutterby Fluid across Shrinking/Stretching Surface.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {12}, number = {4}, pages = {}, pmid = {35214928}, issn = {2079-4991}, abstract = {In this article, we explore how activation energy and varied transit parameters influence the two-dimensional stagnation point motion of nano-biofilm of Sutterby fluids incorporating gyrotactic microbes across a porous straining/shrinking sheet. Prior investigations implied that fluid viscosity as well as thermal conductance are temperature based. This research proposes that fluid viscosity, heat capacity and nanofluid attributes are all modified by solute concentration. According to some empirical research, the viscosity as well as heat conductivity of nanoparticles are highly based on the concentration of nanoparticles instead of only the temperature. The shooting approach with the RK-4 technique is applied to acquire analytical results. We contrast our outcomes with those in the existing research and examine their consistency and reliability. The graphic performance of relevant factors on heat, velocity, density and motile concentration domains are depicted and discussed. The skin friction factor, Nusselt number, Sherwood number and the motile density are determined. As the concentration-dependent properties are updated, the speed, temperature, concentration and motile density profiles are enhanced, but for all concentration-varying factors, other physical quantities deteriorate.}, } @article {pmid35214666, year = {2022}, author = {Su, FJ and Chen, MM}, title = {Protective Efficacy of Novel Oral Biofilm Vaccines against Photobacterium damselae subsp. damselae Infection in Giant Grouper, Epinephelus lanceolatus.}, journal = {Vaccines}, volume = {10}, number = {2}, pages = {}, pmid = {35214666}, issn = {2076-393X}, support = {108MG-8.3.2-B1(2)//Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture, Executive Yuan, R.O.C./ ; }, abstract = {Photobacterium damselae subsp. damselae is a pathogen that mainly infects a variety of fish species. There are many antibiotic-resistant strains of Photobacterium damselae subsp. damselae. In a previously published article, we described the production method for a novel oral biofilm vaccine. In the study reported herein, we confirmed the protective effect of the oral biofilm vaccine against Photobacterium damselae subsp. damselae. Twenty-eight days after vaccination, phagocytosis increased by 256% relative to the control group. The mean albumin-globulin ratios of the vaccine groups were significantly lower than the mean albumin-globulin ratios of the control group. There were no significant intergroup differences in lysozyme activity. Mean IgM titers were significantly higher in the vaccine group than in the control group. There was a significant upregulation of the TLR 3, IL-1β, and IL-8 genes in the spleen 28 days after vaccination. The cumulative mortality of the control fish was 84% after challenging fish with the Photobacterium damselae subsp. damselae, while the cumulative mortality of the oral biofilm vaccine (PBV) group was 32%, which was significantly higher than those of the whole-cell vaccine (PWV) and chitosan particle (CP) groups. There is minimal published research on the prevention and treatment of Photobacterium damselae subsp. damselae infection; therefore, this oral biofilm vaccine may represent a new method to fill this gap.}, } @article {pmid35214158, year = {2022}, author = {Liu, S and Lu, H and Zhang, S and Shi, Y and Chen, Q}, title = {Phages against Pathogenic Bacterial Biofilms and Biofilm-Based Infections: A Review.}, journal = {Pharmaceutics}, volume = {14}, number = {2}, pages = {}, pmid = {35214158}, issn = {1999-4923}, support = {LGF18C200003//Science and Technology Department of Zhejiang Province/ ; }, abstract = {Bacterial biofilms formed by pathogens are known to be hundreds of times more resistant to antimicrobial agents than planktonic cells, making it extremely difficult to cure biofilm-based infections despite the use of antibiotics, which poses a serious threat to human health. Therefore, there is an urgent need to develop promising alternative antimicrobial therapies to reduce the burden of drug-resistant bacterial infections caused by biofilms. As natural enemies of bacteria, bacteriophages (phages) have the advantages of high specificity, safety and non-toxicity, and possess great potential in the defense and removal of pathogenic bacterial biofilms, which are considered to be alternatives to treat bacterial diseases. This work mainly reviews the composition, structure and formation process of bacterial biofilms, briefly discusses the interaction between phages and biofilms, and summarizes several strategies based on phages and their derivatives against biofilms and drug-resistant bacterial infections caused by biofilms, serving the purpose of developing novel, safe and effective treatment methods against biofilm-based infections and promoting the application of phages in maintaining human health.}, } @article {pmid35212897, year = {2022}, author = {Chen, PF and Zhang, RJ and Du, ZL and Wang, GH and Dong, HT and Cui, B and Fan, RP and Li, LX and Wang, QB and Liu, YS and Sun, ZM}, title = {Microbial composition and nitrogen removal pathways in a novel sequencing batch reactor integrated with semi-fixed biofilm carrier: evidence from a pilot study for low- and high-strength sewage treatment.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {32}, pages = {49105-49115}, pmid = {35212897}, issn = {1614-7499}, support = {51778164//Major Research Plan/ ; 51608140//Young Scientists Fund/ ; 2021A1515010499//Basic and Applied Basic Research Program of Guangdong/ ; }, mesh = {Biofilms ; Bioreactors ; Denitrification ; Nitrification ; *Nitrogen ; Oxidation-Reduction ; Pilot Projects ; RNA, Ribosomal, 16S ; *Sewage ; }, abstract = {The sequencing batch reactor (SBR) activated sludge process is a well-established technology for sewage treatment. One of the drawbacks of SBRs, however, total nitrogen (TN) removals is insufficient. By means of introducing four improvements, including semi-fixed biofilm carrier, sludge elevation mixing and change for the mode of influent and effluent, compliant standard for TN discharge was obtained in this novel SBR configuration during low- and high-strength sewage load. To illustrate the microbial compositions and functions of the attached biofilm on semi-fixed carrier and the suspended aggregates, as well as the nitrogen removal pathway, high throughput 16S rRNA gene amplicon sequencing, PICRUSt2 algorithm, and KEGG database were applied. The results revealed that (i) the microbial communities from suspended aggregates and biofilm samples were significantly different from each other; (ii) during low-strength sewage loads, TN removal was mainly by nitrification-denitrification. The suspended aggregates was responsible for denitrification, while the biofilm was focused on ammonium oxidation; (iii) during high-strength sewage loads, function of nitrate reductase from suspended aggregates was faded, and anammox and N assimilation by biofilm became dominant. Meanwhile, TN removal referring to the formation of L-glutamine via assimilation was the main pathway.}, } @article {pmid35212481, year = {2022}, author = {Mariita, RM and Davis, JH and Lottridge, MM and Randive, RV}, title = {Shining light on multi-drug resistant Candida auris: Ultraviolet-C disinfection, wavelength sensitivity, and prevention of biofilm formation of an emerging yeast pathogen.}, journal = {MicrobiologyOpen}, volume = {11}, number = {1}, pages = {e1261}, pmid = {35212481}, issn = {2045-8827}, mesh = {Biofilms/*growth & development/radiation effects ; Candida auris/*drug effects/pathogenicity/physiology/*radiation effects ; Drug Resistance, Multiple/radiation effects ; *Ultraviolet Rays/classification ; }, abstract = {Candida auris is an emerging fungal superbug of worldwide interest. It is associated with high mortality rates and exhibits increased resistance to antifungals. Ultraviolet subtype C (UVC) light can be used to disinfect surfaces to mitigate its spread. The objectives of this study were (1) To investigate UVC disinfection performances and wavelength sensitivity of C. auris. (2) To evaluate the UVC dose required for the prevention of biofilm formation on stainless-steel, plastic (polystyrene), and poly-cotton fabric surfaces. C. auris was grown following standard procedures. The study utilized six different UVC LED arrays with wavelengths between 252 and 280 nm. Arrays were set at similar intensities, to obtain doses of 5-40 mJ cm[-2] and similar irradiation time. Disinfection performance for each array was determined using log reduction value (LRV) and percentage reduction by comparing the controls against the irradiated treatments. Evaluation of the ability of 267 nm UVC LEDs to prevent C. auris biofilm formation was investigated using stainless-steel, plastic coupons, and poly-cotton fabric. Peak sensitivity to UVC disinfection was between 267 and 270 nm. With 20 mJ cm[-2] , the study obtained ≥LRV3. On stainless-steel coupons, 30 mJ cm[-2] was sufficient to prevent biofilm formation, while on plastic, this required 10 mJ cm[-2] . A dose of 60 mJ cm[-2] reduced biofilms on poly-cotton fabric significantly (R[2] = 0.9750, p = 0.0002). The study may allow for the design and implementation of disinfection systems.}, } @article {pmid35211098, year = {2021}, author = {Saber, T and Samir, M and El-Mekkawy, RM and Ariny, E and El-Sayed, SR and Enan, G and Abdelatif, SH and Askora, A and Merwad, AMA and Tartor, YH}, title = {Methicillin- and Vancomycin-Resistant Staphylococcus aureus From Humans and Ready-To-Eat Meat: Characterization of Antimicrobial Resistance and Biofilm Formation Ability.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {735494}, pmid = {35211098}, issn = {1664-302X}, abstract = {Methicillin-resistant and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) are zoonotic life-threatening pathogens, and their presence in food raises a public health concern. Yet, scarce data are available regarding MRSA and VRSA in both ready-to-eat (RTE) meat and food handlers. This study was undertaken to determine the frequency, antimicrobial resistance, and biofilm-forming ability of MRSA and VRSA isolated from RTE meat (shawarma and burger) and humans (food handlers, and hospitalized patients) in Zagazig city, Sharkia Governorate, Egypt. We analyzed 176 samples (112 human samples: 72 from hospitalized patients and 40 from food handlers, 64 RTE meat samples: 38 from shawarma and 26 from burger). Using phenotypic, PCR-based identification of nuc gene and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), 60 coagulase-positive S. aureus (COPS) isolates were identified in the samples as follow: RTE meat (15/64, 23.4%), hospitalized patients (33/72, 45.8%) and food handlers (12/40, 30%). All the COPS isolates were mecA positive (and thus were classified as MRSA) and multidrug resistant with multiple antibiotic resistance indices ranging from 0.25 to 0.92. Overall, resistance to cefepime (96.7%), penicillin (88.3%), were common, followed by ampicillin-sulbactam (65%), ciprofloxacin (55%), nitrofurontoin (51.7%), and gentamicin (43.3%). VRSA was detected in 30.3% of COPS hospitalized patient's isolates, 26.7% of COPS RTE meat isolates and 25% of COPS food handler's isolates. VanA, vanB, or both genes were detected in 64.7, 5.9, and 29.4% of all VAN-resistant isolates, respectively. The majority of the COPS isolates (50/60, 83.3%) have biofilm formation ability and harbored icaA (76%), icaD (74%), icaC (50%), and icaB (46%) biofilm-forming genes. The bap gene was not detected in any of the isolates. The ability of MRSA and VRSA isolates to produce biofilms in addition to being resistant to antimicrobials highlight the danger posed by these potentially virulent microorganisms persisting in RTE meat, food handlers, and patients. Taken together, good hygiene practices and antimicrobial surveillance plans should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA and VRSA biofilm-producing strains.}, } @article {pmid35210150, year = {2022}, author = {Bashyal, RK and Mathew, M and Bowen, E and James, GA and Stulberg, SD}, title = {A Novel Irrigant to Eliminate Planktonic Bacteria and Eradicate Biofilm Superstructure With Persistent Effect During Total Hip Arthroplasty.}, journal = {The Journal of arthroplasty}, volume = {37}, number = {7S}, pages = {S647-S652}, doi = {10.1016/j.arth.2022.01.045}, pmid = {35210150}, issn = {1532-8406}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Arthroplasty, Replacement, Hip ; Bacteria ; Biofilms ; Humans ; Plankton ; *Prosthesis-Related Infections/microbiology ; }, abstract = {BACKGROUND: Numerous studies have examined the use of topical and irrigation-related adjuvants to decrease the risk of periprosthetic joint infection (PJI) after total hip arthroplasty. Many issues related to their use remain to be investigated. These include cost, antibiotic stewardship, bactericidal effect on planktonic bacteria, host cytotoxicity, necessity to irrigate/dilute potentially cytotoxic agents after their application, and impact on biofilm.

METHODS: Bacterial strains of microorganisms were grown in optimal medium. After the growth phase, the organisms were exposed to the novel irrigation solution (XPerience) or phosphate buffer solution (PBS) for 5 minutes before a neutralizing broth was added. The colony-forming units per milliliter and the log reduction in colony-forming units in the treated sample vs the control were then determined. Subsequently, biofilms of microorganisms were grown on hydroxyapatite-coated glass slides. Each slide was then exposed to irrigation solutions for various contact times. Biofilm quantification was performed and the log10 density of each organism was obtained.

RESULTS: In vitro testing of the irrigant demonstrated 6-log reductions in planktonic bacteria in 5 minutes, and 4-log to 8-log reductions in biofilms. Laboratory tissue testing has demonstrated minimal cytotoxic effects to host tissue allowing for solution to remain in contact with the host without need for subsequent irrigation, creating a barrier to biofilm for up to 5 hours after its application.

CONCLUSION: This novel irrigant demonstrates high efficacy against both planktonic bacteria and bacterial biofilms in laboratory testing. Large series in vivo data are necessary to further establish its efficacy in reducing primary and recurrent surgical site infections.}, } @article {pmid35209935, year = {2022}, author = {Shahmoradi, S and Shariati, A and Amini, SM and Zargar, N and Yadegari, Z and Darban-Sarokhalil, D}, title = {The application of selenium nanoparticles for enhancing the efficacy of photodynamic inactivation of planktonic communities and the biofilm of Streptococcus mutans.}, journal = {BMC research notes}, volume = {15}, number = {1}, pages = {84}, pmid = {35209935}, issn = {1756-0500}, support = {97-4-4-13561//Iran University of Medical Sciences/ ; }, mesh = {Biofilms ; *Dental Caries/drug therapy ; Humans ; *Nanoparticles ; Photosensitizing Agents/pharmacology ; Plankton ; *Selenium/pharmacology ; Streptococcus mutans/physiology ; }, abstract = {OBJECTIVE: Streptococcus mutans is one of the principal causative agents of dental caries (tooth decay) found in the oral cavity. Therefore, this study investigates whether selenium nanoparticles (SeNPs) enhance the efficacy of photodynamic therapy (PDT) against both planktonic communities and the one-day-old biofilm of S. mutans. In this study, the planktonic and 24-h biofilm of S. mutans have been prepared in 96-cell microplates. These forms were treated by methylene blue (MB) and SeNPs and then were exposed to light-emitting diode (LED) lighting. Finally, the results have been reported as CFU/ml.

RESULTS: The outcomes demonstrated that MB-induced PDT and SeNPs significantly reduced the number of planktonic bacteria (P-value < 0.001). The comparison between the treated and untreated groups showed that combining therapy with SeNPs and PDT remarkably decreased colony-forming units of one-day-old S. mutans biofilm (P-value < 0.05). The findings revealed that PDT modified by SeNPs had a high potential to destroy S. mutans biofilm. This combination therapy showed promising results to overcome oral infection in dental science.}, } @article {pmid35209759, year = {2022}, author = {Villard, D and Saltnes, T and Sørensen, G and Angell, IL and Eikås, S and Johansen, W and Rudi, K}, title = {Spatial fractionation of phosphorus accumulating biofilm: stratification of polyphosphate accumulation and dissimilatory nitrogen metabolism.}, journal = {Biofouling}, volume = {38}, number = {2}, pages = {162-172}, doi = {10.1080/08927014.2022.2044475}, pmid = {35209759}, issn = {1029-2454}, mesh = {Biofilms ; Nitrogen ; *Phosphorus ; *Polyphosphates ; Wastewater ; }, abstract = {The spatial distribution of microorganisms represents a critical issue in understanding biofilm function. The aim of the current work was to develop a method for biofilm fractionation, facilitating the analysis of individual spatial biofilm layers using metagenomic approaches. Phosphorus accumulating biofilm applied in an enhanced biological phosphorus removal wastewater treatment plant, were fractionated, and analyzed. The fractionated biofilm revealed a surprising spatial distribution of bacteria and genes, where potential polyphosphate accumulating organisms account for ∼ 47% of the inner layer microbiome. A spatial distribution of genes involved in dissimilatory nitrogen reduction was observed, indicating that different layers of the biofilm were metabolically active during the anoxic and aerobic zones of the phosphorus removal process. The physical biofilm separation into individual fractions unveiled functional layers of the biofilm, which will be important for future understanding of the phosphorus removal wastewater process.}, } @article {pmid35209243, year = {2022}, author = {Atta, L and Khalil, R and Khan, KM and Zehra, M and Saleem, F and Nur-E-Alam, M and Ul-Haq, Z}, title = {Virtual Screening, Synthesis and Biological Evaluation of Streptococcus mutans Mediated Biofilm Inhibitors.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {4}, pages = {}, pmid = {35209243}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; *Models, Molecular ; Molecular Conformation ; Molecular Structure ; Quantitative Structure-Activity Relationship ; Streptococcus mutans/*drug effects ; }, abstract = {Dental caries, a global oral health concern, is a biofilm-mediated disease. Streptococcus mutans, the most prevalent oral microbiota, produces extracellular enzymes, including glycosyltransferases responsible for sucrose polymerization. In bacterial communities, the biofilm matrix confers resistance to host immune responses and antibiotics. Thus, in cases of chronic dental caries, inhibiting bacterial biofilm assembly should prevent demineralization of tooth enamel, thereby preventing tooth decay. A high throughput screening was performed in the present study to identify small molecule inhibitors of S. mutans glycosyltransferases. Multiple pharmacophore models were developed, validated with multiple datasets, and used for virtual screening against large chemical databases. Over 3000 drug-like hits were obtained that were analyzed to explore their binding mode. Finally, six compounds that showed good binding affinities were further analyzed for ADME (absorption, distribution, metabolism, and excretion) properties. The obtained in silico hits were evaluated for in vitro biofilm formation. The compounds displayed excellent antibiofilm activities with minimum inhibitory concentration (MIC) values of 15.26-250 µg/mL.}, } @article {pmid35209008, year = {2022}, author = {Das, B and Kar, A and Bhowmik, R and Karmakar, S and Tripathy, S and Matsabisa, MG and Mukherjee, PK}, title = {Quality Related Safety Evaluation of a South African Traditional Formulation (PHELA[®]) as Novel Anti-Biofilm Candidate.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {4}, pages = {}, pmid = {35209008}, issn = {1420-3049}, support = {DST/INT/South Africa/P-17/2016//Department of Science and Technology/ ; 104775//DST-NRF/ ; }, mesh = {Anti-Infective Agents/*chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Chromatography, High Pressure Liquid ; Dose-Response Relationship, Drug ; Humans ; Mass Spectrometry ; *Medicine, African Traditional ; Microbial Sensitivity Tests ; Plant Extracts/*chemistry/isolation & purification/*pharmacology ; }, abstract = {A South African traditional formulation, PHELA[®], is consumed by the traditional people for severe chest problems with coughing, diarrhea, oral ulcers etc. The present study focused on establishing the anti-infective properties of a safe and standardized poly-herbal formulation through a series of criteria and specifications.}, } @article {pmid35208922, year = {2022}, author = {Goodman, SD and Bakaletz, LO}, title = {Bacterial Biofilms Utilize an Underlying Extracellular DNA Matrix Structure That Can Be Targeted for Biofilm Resolution.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208922}, issn = {2076-2607}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC011818/NH/NIH HHS/United States ; R01 AI155501/AI/NIAID NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 DC003915/NH/NIH HHS/United States ; R01 AI155501/NH/NIH HHS/United States ; }, abstract = {Bacterial biofilms contribute significantly to the antibiotic resistance, pathogenesis, chronicity and recurrence of bacterial infections. Critical to the stability and survival of extant biofilms is the extracellular DNA (eDNA)-dependent matrix which shields the resident bacteria from hostile environments, allows a sessile metabolic state, but also encourages productive interactions with biofilm-inclusive bacteria. Given the importance of the eDNA, approaches to this area of research have been to target not just the eDNA, but also the additional constituent structural components which appear to be widespread. Chief among these is a ubiquitous two-member family of bacterial nucleoid associated proteins (the DNABII proteins) responsible for providing structural integrity to the eDNA and thereby the biofilm. Moreover, this resultant novel eDNA-rich secondary structure can also be targeted for disruption. Here, we provide an overview of both what is known about the eDNA-dependent matrix, as well as the resultant means that have resulted in biofilm resolution. Results obtained to date have been highly supportive of continued development of DNABII-targeted approaches, which is encouraging given the great global need for improved methods to medically manage, or ideally prevent biofilm-dependent infections, which remains a highly prevalent burden worldwide.}, } @article {pmid35208893, year = {2022}, author = {Kiel, A and Kaltschmidt, BP and Asghari, E and Hütten, A and Kaltschmidt, B and Kaltschmidt, C}, title = {Bacterial Biofilm Formation on Nano-Copper Added PLA Suited for 3D Printed Face Masks.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208893}, issn = {2076-2607}, abstract = {The COVID-19 Pandemic leads to an increased worldwide demand for personal protection equipment in the medical field, such as face masks. New approaches to satisfy this demand have been developed, and one example is the use of 3D printing face masks. The reusable 3D printed mask may also have a positive effect on the environment due to decreased littering. However, the microbial load on the 3D printed objects is often disregarded. Here we analyze the biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli on suspected antimicrobial Plactive™ PLA 3D printing filaments and non-antimicrobial Giantarm™ PLA. To characterize the biofilm-forming potential scanning electron microscopy (SEM), Confocal scanning electron microscopy (CLSM) and colony-forming unit assays (CFU) were performed. Attached cells could be observed on all tested 3D printing materials. Gram-negative strains P. aeruginosa and E. coli reveal a strong uniform growth independent of the tested 3D filament (for P. aeruginosa even with stressed induced growth reaction by Plactive™). Only Gram-positive S. aureus shows strong growth reduction on Plactive™. These results suggest that the postulated antimicrobial Plactive™ PLA does not affect Gram-negative bacteria species. These results indicate that reusable masks, while better for our environment, may pose another health risk.}, } @article {pmid35208842, year = {2022}, author = {Wollanke, B and Gerhards, H and Ackermann, K}, title = {Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208842}, issn = {2076-2607}, abstract = {Uveitis is a sight-threatening eye disease in equids known worldwide that leads to considerable pain and suffering. By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses. Other infectious causes are extremely rare and are usually clinically distinguishable from ERU. ERU can be treated very effectively by vitreous cavity lavage (vitrectomy). For proper indications of this demanding surgery, it is necessary to differentiate ERU from other types of uveitis in which vitrectomy is not helpful. This can be conducted on the basis of anamnesis in combination with ophthalmologic findings and by aqueous humor examination. During vitrectomy, vitreous material is obtained. These vitreous samples have historically been used for numerous etiologic studies. In this way, a chronic intraocular leptospiral infection has been shown to be the cause of typical ERU and, among other findings, ERU has also been recognized as a biofilm infection, providing new insights into the pathogenesis of ERU and explaining some thus far unexplainable phenomena of ERU. ERU may not only have transmissible aspects to some types of uveitis in humans but may also serve as a model for a spontaneously occurring biofilm infection. Vitreous material obtained during therapeutically indicated vitrectomy can be used for further studies on in vivo biofilm formation, biofilm composition and possible therapeutic approaches.}, } @article {pmid35208812, year = {2022}, author = {Wang, Y and Huang, Z and Zhou, N and Liu, C and Jiang, C and Li, D and Liu, S}, title = {The Response Regulator FlmD Regulates Biofilm Formation in Comamonas testosteroni through the Transcriptional Activator SoxR.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208812}, issn = {2076-2607}, support = {2019YFA0905500//Ministry of Science and Technology of the People's Republic of China/ ; }, abstract = {Biofilm formation is a survival strategy by which microorganisms adapt to environmental challenges. It is regulated by various signals, such as the second messenger c-di-GMP. We previously found that the Flm chemosensory pathway could respond to chemical signals and regulate biofilm formation. This regulation is independent of c-di-GMP. A previous study revealed that the response regulator FlmD is involved in biofilm formation; however, how chemical signals are transmitted downstream of FlmD remained unclear. In the present study, transcriptome analysis and gel shift assay reveal that SoxR, a transcriptional activator of the efflux transporter acrAB-tolC operon, mediates the downstream signaling of FlmD. Phosphorylated FlmD interacts with SoxR and disrupts the interaction between SoxR and the acrAB-tolC operon. It causes a decrease in the expression of acrAB-tolC operon. The downregulation of acrA, acrB, or tolC gene expression results in making less biofilm formation. In conclusion, we identified that the transcription regulator SoxR plays a role in the c-di-GMP independent regulation of biofilm formation in Comamonas testosteroni.}, } @article {pmid35208802, year = {2022}, author = {Jimi, S and Yoshimura, M and Mashima, K and Ueda, Y and Miyazaki, M and Saparov, A}, title = {Intracellular Survival of Biofilm-Forming MRSA OJ-1 by Escaping from the Lysosome and Autophagosome in J774A Cells Cultured in Overdosed Vancomycin.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208802}, issn = {2076-2607}, abstract = {We investigated the drug-resistant mechanisms of intracellular survival of methicillin-resistant S. aureus (MRSA). Our established MRSA clinical strain, OJ-1, with high biofilm-forming ability, and a macrophage cell line, J774A, were used. After ingestion of OJ-1 by J774A, the cells were incubated for ten days with vancomycin at doses 30 times higher than the minimum inhibitory concentration. The number of phagocytosed intracellular OJ-1 gradually decreased during the study but plateaued after day 7. In J774A cells with intracellular OJ-1, the expression of LysoTracker-positive lysosomes increased until day 5 and then declined from day 7. In contrast, LysoTracker-negative and OJ-1-retaining J774A cells became prominent from day 7, and intracellular OJ-1 also escaped from the autophagosome. Electron microscopy also demonstrated that OJ-1 escaped the phagosomes and was localized in the J774A cytoplasm. At the end of incubation, when vancomycin was withdrawn, OJ-1 started to grow vigorously. The present results indicate that intracellular phagocytosed biofilm-forming MRSA could survive for more than ten days by escaping the lysosomes and autophagosomes in macrophages. Intracellular MRSA may survive in macrophages, and accordingly, they could be resistant to antimicrobial drug treatments. However, the mechanisms their escape from the lysosomes are still unknown. Additional studies will be performed to clarify the lysosome-escaping mechanisms of biofilm-forming MRSA.}, } @article {pmid35208707, year = {2022}, author = {Sornchuer, P and Saninjuk, K and Prathaphan, P and Tiengtip, R and Wattanaphansak, S}, title = {Antimicrobial Susceptibility Profile and Whole-Genome Analysis of a Strong Biofilm-Forming Bacillus Sp. B87 Strain Isolated from Food.}, journal = {Microorganisms}, volume = {10}, number = {2}, pages = {}, pmid = {35208707}, issn = {2076-2607}, support = {2-16/2563//Faculty of Medicine, Thammasat University, Thailand/ ; //Research Group in Multidrug resistant bacteria and the antimicrobial herbal extracts, Faculty of Medicine, Thammasat University/ ; //Thammasat University Research Unit in Neutraceuticals and Food Safety/ ; }, abstract = {Members of the Bacillus cereus group are considered to be foodborne pathogens commonly associated with diarrheal and emetic gastrointestinal syndromes. Biofilm formation is a major virulence determinant of various pathogenic bacteria, including the B. cereus strains, since it can protect the bacteria against antimicrobial agents and the host immune response. Moreover, a biofilm allows the exchange of genetic material, such as antimicrobial resistance genes, among the different bacterial strains inside the matrix. The aim of the current study was to genotypically and phenotypically characterize Bacillus sp. B87, a strain that was isolated from food and which exhibited strong biofilm-forming capacity. Based on the analysis of the phylogenetic relationship, the isolate was phylogenetically mapped close to Bacillus pacificus. Antimicrobial susceptibility testing revealed that the isolate was resistant to tetracycline and β-lactam antimicrobial agents, which corresponded with the genotypic characterization using the whole-genome analysis. The genome of Bacillus sp. B87 carried the three-component non-hemolytic enterotoxin (NHE), which is a type of enterotoxin that causes diarrheal symptoms. In addition, the genome also contained several genes that participate in biofilm formation, including the pelDEADAFG operon. These findings expand our understanding of antimicrobial resistance and virulence in Bacillus species based on the link between genotypic and phenotypic characterization.}, } @article {pmid35207524, year = {2022}, author = {Becerikli, M and Wallner, C and Dadras, M and Wagner, JM and Dittfeld, S and Jettkant, B and Gestmann, F and Mehlhorn, H and Mehlhorn-Diehl, T and Lehnhardt, M and Behr, B}, title = {Maggot Extract Interrupts Bacterial Biofilm Formation and Maturation in Combination with Antibiotics by Reducing the Expression of Virulence Genes.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {35207524}, issn = {2075-1729}, support = {ZF4048804NK7//Federal Ministry for Economic Affairs and Energy/ ; }, abstract = {Biofilms are aggregates of bacteria encased in an extracellular polymer matrix that acts as a diffusion barrier protecting the microbial community. Bacterial communication occurs by small signaling molecules called quorum sensing (QS) factors, which are involved in the activation of virulence genes and formation of biofilms. Larvae of the green bottle blowfly Lucilia sericata remove necrotic tissue by mechanical action (debridement) and proteolytic digestion. We produced a freeze-dried storable powder from larval extract and investigated its therapeutic effect on biofilms. Larval extract in concentrations of 6 and 12 mg/mL in combination with 0.5% antibiotics (≙50 U/mL penicillin and 50 μg/mL streptomycin) diminished free-floating (planktonic) Pseudomonas aeruginosa maintenance, while it showed no effect on Staphylococcus aureus and was not toxic to dermal cells. We established an ex vivo human dermal wound model. Larval extract in concentrations of 24 and 75 mg/mL in the presence of antibiotics (0.5%) significantly destroyed the biofilm stability of both P. aeruginosa and S. aureus biofilms. Furthermore, SEM analyses revealed crack and gap formations on P. aeruginosa. biofilm surface and decreased expression of P. aeruginosa biofilm maturation and virulence genes (lasR, rhlR and rhlA) was observed after treatment by larval extract in combination with antibiotics.}, } @article {pmid35206183, year = {2022}, author = {Wang, L and Wang, Y and Li, Y and Zhang, W and Zhang, H and Niu, L and Habibul, N}, title = {Benthic Biofilm Bacterial Communities and Their Linkage with Water-Soluble Organic Matter in Effluent Receivers.}, journal = {International journal of environmental research and public health}, volume = {19}, number = {4}, pages = {}, pmid = {35206183}, issn = {1660-4601}, mesh = {Bacteria ; Biofilms ; Rivers/chemistry ; *Wastewater/chemistry ; *Water ; }, abstract = {Benthic biofilms are pioneering microbial aggregates responding to effluent discharge from wastewater treatment plants (WWTPs). However, knowledge of the characteristics and linkage of bacterial communities and water-soluble organic matter (WSOM) of benthic biofilms in effluent-receiving rivers remains unknown. Here, we investigated the quality of WSOM and the evolution of bacterial communities in benthic biofilm to evaluate the ecological impacts of effluent discharge on a representative receiving water. Tryptophan-like proteins showed an increased proportion in biofilms collected from the discharge area and downstream from the WWTP, especially in summer. Biofilm WSOM showed weak humic character and strong autochthonous components, and species turnover was proven to be the main factor governing biofilm bacteria community diversity patterns. The bacterial community alpha diversity, interspecies interaction, biological index, and humification index were signally altered in the biofilms from the discharge area, while the values were more similar in biofilms collected upstream and downstream from the WWTP, indicating that both biofilm bacterial communities and WSOM characters have resilience capacities. Although effluent discharge simplified the network pattern of the biofilm bacterial community, its metabolic functional abundance was basically stable. The functional abundance of carbohydrate metabolism and amino acid metabolism in the discharge area increased, and the key modules in the non-random co-occurrence network also verified the important ecological role of carbon metabolism in the effluent-receiving river. The study sheds light on how benthic biofilms respond to effluent discharge from both ecological and material points of view, providing new insights on the feasibility of utilizing benthic biofilms as robust indicators reflecting river ecological health.}, } @article {pmid35204726, year = {2022}, author = {Marin, C and Kumova, OK and Ninio, S}, title = {Characterization of a Novel Regulator of Biofilm Formation in the Pathogen Legionella pneumophila.}, journal = {Biomolecules}, volume = {12}, number = {2}, pages = {}, pmid = {35204726}, issn = {2218-273X}, mesh = {*Amoeba ; Biofilms ; Humans ; *Legionella pneumophila/genetics ; *Legionnaires' Disease/metabolism/microbiology ; Virulence/genetics ; }, abstract = {Legionella pneumophila is a Gram-negative, facultative intracellular pathogen that causes severe pneumonia known as Legionnaires' disease. The bacterium causes disease when contaminated water is aerosolized and subsequently inhaled by individuals, which allows the bacteria to gain access to the lungs, where they infect alveolar macrophages. L. pneumophila is ubiquitous in the environment, where it survives by growing in biofilms, intracellularly within protozoa, and planktonically. Biofilms are a major concern for public health because they provide a protective niche that allows for the continuous leaching of bacteria into the water supply. In addition, biofilms enhance the survival of the bacteria by increasing resistance to temperature fluctuations and antimicrobial agents. Currently, there is little known about biofilm formation and regulation by L. pneumophila. Here, we present evidence of a specific gene, bffA, which appears to be involved in the regulation of motility, biofilm formation, cellular replication, and virulence of L. pneumophila. A strain lacking bffA has an enhanced biofilm formation phenotype, forming biofilms that are both faster and thicker than wild type. Additionally, the knockout strain has significantly reduced motility, enhanced uptake into amoebae, and altered growth kinetics on solid media. Our data suggest a potential role for bffA in signaling pathways that govern changes in growth rate and motility in response to environmental conditions.}, } @article {pmid35203863, year = {2022}, author = {Jin, F and Yang, H}, title = {Transcriptome Analysis of the Response of Mature Helicobacter pylori Biofilm to Different Doses of Lactobacillus salivarius LN12 with Amoxicillin and Clarithromycin.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {2}, pages = {}, pmid = {35203863}, issn = {2079-6382}, support = {HUCXY-2016-010//Shanghai Industry-University Joint Research Program/ ; }, abstract = {Helicobacter pylori is a gastrointestinal pathogen with a high infection rate. Probiotics are clinically used as an adjuvant to improve the cure rate and reduce the side effects of antibiotic treatment for H. pylori. This study is the first to explore the effects of a cell-free supernatant of high- or low-dose Lactobacillus salivarius LN12 combined with amoxicillin (AMX) and clarithromycin (CLR) on H. pylori 3192 biofilms in terms of the biofilm biomass, survival rates, biofilm structure, and transcriptome. The results showed that the combination of the CFS of high-dose LN12 with AMX and CLR had stronger effects on the biofilm biomass, survival rate, and structure of H. pylori 3192 biofilms. H. pylori 3192 biofilms may increase the expression of NADH-related genes and downregulate flagellar assembly and quorum sensing-related receptor genes to deal with the stronger stress effects of high-dose LN12 with AMX and CLR. In conclusion, the biofilm biomass, survival rate, structure, and transcriptome results showed that the combination of LN12 CFS with AMX and CLR had dose effects. We recommend that compared with low doses, high doses of L. salivarus LN12 combined with AMX and CLR may be more effective for H. pylori biofilm than low doses.}, } @article {pmid35203751, year = {2022}, author = {Kwiatkowski, P and Sienkiewicz, M and Pruss, A and Łopusiewicz, Ł and Arszyńska, N and Wojciechowska-Koszko, I and Kilanowicz, A and Kot, B and Dołęgowska, B}, title = {Antibacterial and Anti-Biofilm Activities of Essential Oil Compounds against New Delhi Metallo-β-Lactamase-1-Producing Uropathogenic Klebsiella pneumoniae Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {2}, pages = {}, pmid = {35203751}, issn = {2079-6382}, abstract = {The World Health Organization points out that the opportunistic pathogen Klebsiella pneumoniae that causes various infections among others, urinary tract infections (UTIs), is one of the high-priority species due to a global problem of antimicrobial resistance. The aim of this study was to investigate antibacterial and anti-biofilm activities of chosen constituents of essential oils against NDM-1-producing, uropathogenic K. pneumoniae strains. The genes encoding lipopolysaccharide (uge, wabG), adhesin gene fimH (type I fimbriae) and gene encoding carbapenemase (blaNDM-1) for all tested strains were detected by PCR amplification. The K. pneumoniae ATCC BAA-2473 reference strain was uge- and blaNDM-1-positive. The effectiveness of fifteen essential oil compounds (EOCs) (linalool, β-citronellol, linalyl acetate, menthone, (-)-menthol, (+)-menthol, geraniol, eugenol, thymol, trans-anethole, farnesol, β-caryophyllene, (R)-(+)-limonene, 1,8-cineole, and carvacrol) was assessed by determining the MIC, MBC, MBC/MIC ratio against K. pneumoniae strains by the microdilution method. Anti-biofilm properties of these compounds were also investigated. Thymol, carvacrol and geraniol exhibited the best antibacterial and anti-biofilm activities against uropathogenic NDM-1-producing K. pneumoniae isolates. Results of our investigations provide a basis for more detailed studies of these phytochemicals on their application against uropathogenic K. pneumoniae.}, } @article {pmid35203130, year = {2022}, author = {Płókarz, D and Czopowicz, M and Bierowiec, K and Rypuła, K}, title = {Virulence Genes as Markers for Pseudomonas aeruginosa Biofilm Formation in Dogs and Cats.}, journal = {Animals : an open access journal from MDPI}, volume = {12}, number = {4}, pages = {}, pmid = {35203130}, issn = {2076-2615}, abstract = {Pseudomonas aeruginosa is an ubiquitous bacterium and opportunistic pathogen that plays an important role in nosocomial infections. The presence of virulence factors and the biofilm-forming ability of this species contributes to a high risk of treatment complications. In this study, we examined the biofilm-forming ability and the prevalence of five virulence factor genes (pslA, pelA, ppyR, fliC, and nan1) in 271 P. aeruginosa isolates (212 from dogs and 59 from cats). Biofilm-forming ability was detected in 90.6% of isolates in dogs and 86.4% of isolates in cats. In P. aeruginosa isolates from both species, the most prevalent virulence factor gene was ppyR (97.2% in dogs and 98.3% in cats), followed by pslA (60.8% and 57.6%), fliC (60.4% and 69.5%), nan1 (45.3% and 44.1%), and pelA (40.1% and 33.9%, respectively). In dogs, a significantly higher proportion of biofilm-forming P. aeruginosa strains possessed the fliC gene compared to non-biofilm-forming strains (p = 0.015). In cats, a significantly lower proportion of biofilm-forming strains had the nan1 gene compared to non-biofilm-forming strains (p = 0.017). In conclusion, the presence of fliC gene and the absence of nan1 gene could be indicators of biofilm-forming ability of P. aeruginosa.}, } @article {pmid35202839, year = {2022}, author = {Thorn, CR and Kopecki, Z and Wignall, A and Kral, A and Prestidge, CA and Thomas, N}, title = {Liquid crystal nanoparticle platform for increased efficacy of cationic antimicrobials against biofilm infections.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {42}, number = {}, pages = {102536}, doi = {10.1016/j.nano.2022.102536}, pmid = {35202839}, issn = {1549-9642}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; Biofilms ; Caenorhabditis elegans ; Cations ; *Liquid Crystals ; Mice ; *Nanoparticles ; Pseudomonas aeruginosa ; Swine ; Tobramycin/pharmacology ; }, abstract = {Bacterial biofilm infections tolerate high concentrations of antibiotics and are insidiously challenging to treat. Liquid crystal nanoparticles (LCNPs) advance the efficacy of tobramycin in biofilm-related infections by increasing the penetration of antibiotics across the biofilm matrix. Herewith, we develop the LCNPs as a platform technology, demonstrating that the LCNPs can increase the efficacy of two antibiotic classes (i.e. aminoglycosides and colistin) in P. aeruginosa biofilm infections. In C. elegans, the LCNPs potentiated the antimicrobial effect and significantly improved the survival of the nematodes. In mice with a full-thickness excisional wound, LCNPs were non-toxic and did not impair wound repair. Compared to the unformulated antibiotic treatment, tobramycin-LCNPs reduced the chronic bacterial load by 100-fold in the wound. This was also emulated in an ex vivo P. aeruginosa porcine wound infection model. The LCNPs represent a versatile platform technology that improves the efficacy of cationic antibiotics against biofilm infections utilizing multiple administration routes.}, } @article {pmid35202827, year = {2022}, author = {Yang, S and Peng, Y and Zhang, Q and Li, J and Zhang, L}, title = {Biofilm phenotypes and internal community succession determines distinct growth of anammox bacteria in functional anammox biofilms.}, journal = {Bioresource technology}, volume = {349}, number = {}, pages = {126893}, doi = {10.1016/j.biortech.2022.126893}, pmid = {35202827}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Bacteria/genetics ; Biofilms ; *Bioreactors/microbiology ; Nitrogen ; Oxidation-Reduction ; Phenotype ; RNA, Ribosomal, 16S/genetics ; }, abstract = {In this study, time-series anammox functional biofilms were obtained in a lab-scale simultaneous partial nitritation/anammox process for treating high-strength ammonium. The variations in the biofilm phenotypes, community succession, and anammox bacteria abundance over time were evaluated using optical microscopy, 16S rRNA gene sequencing, and qPCR. The result revealed that biofilm has three distinct stages of the community development trajectory across a 182-day temporal scale. Anammox bacteria growth rates were 0.035 d[-1], 0.0015 d[-1], and 0.011 d[-1], respectively. The diversity and network analysis suggested that the positive priority effect of ammonia oxidizing bacteria was the primary factor for the rapid proliferation of anammox bacteria, and the species replacement triggering priority effect forfeiture and substituted functional recruitment were reasons for the slow proliferation and stable proliferation of anammox bacteria, respectively. Taken together, the higher microbial diversity and stable community composite were key prerequisites for the proliferation of the anammox bacteria.}, } @article {pmid35202826, year = {2022}, author = {He, X and Xie, X and Xu, H and Liu, J and Li, B and Zhang, Q}, title = {Promoted removal of phosphate by layered double hydroxides combined with bacteria: Application of novel carriers in biofilm reactor.}, journal = {Bioresource technology}, volume = {349}, number = {}, pages = {126879}, doi = {10.1016/j.biortech.2022.126879}, pmid = {35202826}, issn = {1873-2976}, mesh = {Adsorption ; Bacteria ; Biofilms ; Bioreactors ; Hydroxides/pharmacology ; *Phosphates ; *Water Pollutants, Chemical ; }, abstract = {Layered double hydroxides (LDHs) were used as carriers for the microbial consortium in sequencing biofilm batch reactor (SBBR) without inoculation to promote the removal of phosphate. The adsorption capacity of [Zn-Al]-LDH was significantly better than that of [Mg-Al]-LDH. The pollutants removal performance and behavior of microorganisms in LDH-SBBRs were also investigated. LDH-SBBRs showed improved removal efficiencies of COD, phosphate and TP with a low C/N ratio. Microscopic images show that biofilm formed rapidly in LDH-SBBRs. SEM-EDS detected abundant carbon and phosphorus, implying that biomass and phosphorus accumulate on LDH carriers. The microbial compositions of the three SBBRs indicate that the LDHs carriers improved the biodiversity of biofilm in the bioreactors. Synergistic effects of adsorption and biodegradation between well-structured LDHs and microorganisms led to an improved phosphate removal performance of LDH-SBBR. The results also demonstrate that [Zn-Al]-LDH carrier is the best for improving SBBR phosphate removal.}, } @article {pmid35201606, year = {2022}, author = {Mannala, GK and Rupp, M and Walter, N and Brunotte, M and Alagboso, F and Docheva, D and Brochhausen, C and Alt, V}, title = {Microbiological and ultrastructural evaluation of bacteriophage 191219 against planktonic, intracellular and biofilm infection with Staphylococcus aureus.}, journal = {European cells & materials}, volume = {43}, number = {}, pages = {66-78}, doi = {10.22203/eCM.v043a07}, pmid = {35201606}, issn = {1473-2262}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriophages ; Biofilms ; Gentamicins/pharmacology ; Humans ; Plankton ; Rifampin/pharmacology ; *Staphylococcal Infections/therapy ; Staphylococcus aureus ; }, abstract = {Infections of orthopaedic implants, such as fracture fixation devices and total-joint prostheses, are devastating complications. Staphylococcus aureus (S. aureus) is a predominant pathogen causing orthopaedic-implant biofilm infections that can also internalise and persist in osteoblasts, thus resisting antibiotic therapy. Bacteriophages are a promising alternative treatment approach. However, data on the activity of bacteriophages against S. aureus, especially during intracellular growth, and against in vivo biofilm formation on metals are scarce. Therefore, the present study evaluated the in vitro efficacy of S. aureus bacteriophage 191219, alone as well as in combination with gentamicin and rifampicin, to eradicate S. aureus strains in their planktonic stage, during biofilm formation and after internalisation into osteoblasts. Further, the invertebrate model organism Galleria mellonella was used to assess the activity of the bacteriophage against S. aureus biofilm on metal implants with and without antibiotics. Results demonstrated the in vitro efficacy of bacteriophage 191219 against planktonic S. aureus. The phage was also effective against in vitro S. aureus biofilm formation in a dose-dependent manner and against S. aureus internalised in an osteoblastic cell line. Transmission electron microscopy (TEM) analysis showed bacteriophages on S. aureus inside the osteoblasts, with the destruction of the intracellular bacteria and formation of new bacteriophages. For the Galleria mellonella infection model, single administration of phage 191219 failed to show an improvement in survival rate but appeared to show a not statistically significant enhanced effect with gentamicin or rifampicin. In summary, bacteriophages could be a potential adjuvant treatment strategy for patients with implant-associated biofilm infections.}, } @article {pmid35201371, year = {2022}, author = {Jaekel, C and Windolf, CD and Sager, M and Wollschläger, LM and Hoffmanns, M and Grassmann, JP}, title = {Plate-associated localized osteitis in mini-pig by biofilm-forming Methicillin-resistant Staphylococcus aureus (MRSA): establishment of a novel experimental model.}, journal = {European journal of trauma and emergency surgery : official publication of the European Trauma Society}, volume = {48}, number = {4}, pages = {3279-3285}, pmid = {35201371}, issn = {1863-9941}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Models, Theoretical ; *Osteitis/drug therapy/etiology ; *Staphylococcal Infections/drug therapy ; Swine ; Swine, Miniature ; Titanium/therapeutic use ; }, abstract = {PURPOSE: The increasing number of implant-associated infections during trauma and orthopedic surgery caused by biofilm-forming Staphylococcus aureus in combination with an increasing resistance of conventional antibiotics requires new therapeutic strategies. One possibility could be testing for different therapeutic strategies with differently coated plates. Therefore, a clinically realistic model is required. The pig offers the best comparability to the human situation, thus it was chosen for this model. The present study characterizes a novel model of a standardized low-grade acute osteitis with bone defect in the femur in mini-pigs, which is stabilized by a titanium locking plate to enable further studies with various coatings.

METHODS: A bone defect was performed on the femur of 7 Aachen mini-pigs and infected with Methicillin-resistant S. aureus (MRSA ATCC 33592). The defect zone was stabilized with a titanium plate. After 14 days, a plate change, wound debridement and lavage were performed. Finally, after 42 days, the animals were lavaged and debrided again, followed by euthanasia. The fracture healing was evaluated radiologically and histologically.

RESULTS: A local osteitis with radiologically visible lysis of the bone could be established. The unchanged high Colony-forming Units (CFU) in lavage, the significant differences in Interleukin (IL)-6 in blood compared to lavage and the lack of increase in Alkaline Phosphates (ALP) in serum over the entire observation period show the constant local infection.

CONCLUSION: The study shows the successful induction of local osteitis with lysis of the bone and the lack of enzymatic activity to mineralize the bone. Therefore, this standardized mini-pig model can be used in further clinical studies, to investigate various coated implants, bone healing, biofilm formation and immune response in implant-associated osteitis.}, } @article {pmid35200620, year = {2022}, author = {Wang, KL and Dou, ZR and Gong, GF and Li, HF and Jiang, B and Xu, Y}, title = {Anti-Larval and Anti-Algal Natural Products from Marine Microorganisms as Sources of Anti-Biofilm Agents.}, journal = {Marine drugs}, volume = {20}, number = {2}, pages = {}, pmid = {35200620}, issn = {1660-3397}, support = {32060032//the National Natural Science Foundations of China/ ; 41706155//the National Natural Science Foundations of China/ ; JCYJ20210324093409025//the Shenzhen Science and Technology Program/ ; 202001AT070022//the Natural Science Foundation of Yunnan Province of China/ ; ZKLX2019106//the Development and Utilization of Characteristic Medicinal Plants in Western Yunnan & Bai Nationality Medicines/ ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/isolation & purification/pharmacology ; Aquatic Organisms/*metabolism ; Bacteria/drug effects ; Biofilms/*drug effects ; Biofouling/prevention & control ; Biological Products/chemistry/isolation & purification/*pharmacology ; Humans ; Larva/drug effects ; Structure-Activity Relationship ; }, abstract = {Bacteria growing inside biofilms are more resistant to hostile environments, conventional antibiotics, and mechanical stresses than their planktonic counterparts. It is estimated that more than 80% of microbial infections in human patients are biofilm-based, and biofouling induced by the biofilms of some bacteria causes serious ecological and economic problems throughout the world. Therefore, exploring highly effective anti-biofilm compounds has become an urgent demand for the medical and marine industries. Marine microorganisms, a well-documented and prolific source of natural products, provide an array of structurally distinct secondary metabolites with diverse biological activities. However, up to date, only a handful of anti-biofilm natural products derived from marine microorganisms have been reported. Meanwhile, it is worth noting that some promising antifouling (AF) compounds from marine microbes, particularly those that inhibit settlement of fouling invertebrate larvae and algal spores, can be considered as potential anti-biofilm agents owing to the well-known knowledge of the correlations between biofilm formation and the biofouling process of fouling organisms. In this review, a total of 112 anti-biofilm, anti-larval, and anti-algal natural products from marine microbes and 26 of their synthetic analogues are highlighted from 2000 to 2021. These compounds are introduced based on their microbial origins, and then categorized into the following different structural groups: fatty acids, butenolides, terpenoids, steroids, phenols, phenyl ethers, polyketides, alkaloids, flavonoids, amines, nucleosides, and peptides. The preliminary structure-activity relationships (SAR) of some important compounds are also briefly discussed. Finally, current challenges and future research perspectives are proposed based on opinions from many previous reviews.}, } @article {pmid35199816, year = {2022}, author = {Shi, T and Ruan, Z and Wang, X and Lian, X and Chen, Y}, title = {Erythrocyte membrane-enveloped molybdenum disulfide nanodots for biofilm elimination on implants via toxin neutralization and immune modulation.}, journal = {Journal of materials chemistry. B}, volume = {10}, number = {11}, pages = {1805-1820}, doi = {10.1039/d1tb02615a}, pmid = {35199816}, issn = {2050-7518}, mesh = {Biofilms ; Disulfides ; *Erythrocyte Membrane ; *Molybdenum/pharmacology ; *Nanotubes ; Reactive Oxygen Species ; }, abstract = {Implant-related infections (IRIs) caused by bacterial biofilms remain a prevalent but tricky clinical issue, and are characterized by drug resistance, toxin impairment and immunosuppression. Recently, reactive oxygen species (ROS)- and hyperthermia-based antimicrobial therapies have been developed to effectively destroy biofilms. However, almost all of them have failed to simultaneously focus on the immunosuppressive biofilm microenvironment and bacterial toxin-induced tissue damage. Herein, we proposed a one-arrow-three-hawks strategy to orchestrate hyperthermia/ROS antibiofilm therapy, toxin neutralization and immunomodulatory therapy through engineering a bioinspired erythrocyte membrane-enveloped molybdenum disulfide nanodot (EM@MoS2) nanoplatform. In the biofilm microenvironment, pore-forming toxins actively attack the erythrocyte membranes on the nanodots and are detained, thus staying away from their targets and mitigating tissue damage. Under near-infrared (NIR) laser irradiation, MoS2 nanodots, with superb photothermal and peroxidase (POD)-like properties, exert a powerful synergistic antibiofilm effect. More intriguingly, we initially identified that they possessed the ability to reverse the immunosuppressive microenvironment by skewing the macrophages from an anti-inflammatory phenotype to a proinflammatory phenotype, which would promote the elimination of biofilm debris and prevent infection relapse. Systematic in vitro and in vivo evaluations have demonstrated that EM@MoS2 achieves a remarkable antibiofilm effect. The current study integrated the functions of hyperthermia/ROS therapy, virulence clearance and immune regulation, which could provide an effective paradigm for IRIs therapy.}, } @article {pmid35198213, year = {2022}, author = {Hobson, KA and Kuwae, T and Drever, MC and Easton, WE and Elner, RW}, title = {Biofilm and invertebrate consumption by western sandpipers (Calidris mauri) and dunlin (Calidris alpina) during spring migratory stopover: insights from tissue and breath CO2 isotopic (δ [13]C, δ [15]N) analyses.}, journal = {Conservation physiology}, volume = {10}, number = {1}, pages = {coac006}, pmid = {35198213}, issn = {2051-1434}, abstract = {Shorebirds use key migratory stopover habitats in spring and fall where body proteins are replenished and lipids stored as fuel for the remaining journey. The Fraser River estuary, British Columbia, Canada, is a critical spring stopover site for hundreds of thousands of migrating western sandpiper, Calidris mauri, and dunlin, Calidris alpina. Intertidal biofilm in spring is an important nutritional source for western sandpiper, with previous isotopic research predicting 45-59% of total diet and 50% of total energy needs. However, these studies relied on isotopic mixing models that did not consider metabolic routing of key dietary macromolecules. Complexity arises due to the mixed macromolecular composition of biofilm that is difficult to characterize isotopically. We expanded on these earlier findings by considering a protein pathway from diet to the body protein pool represented by liver tissue, using a Bayesian mixing model based on δ [13]C and δ [15]N. We used δ [13]C measurements of adipose tissue and breath CO2 to provide an estimate of the carbohydrate and protein δ [13]C values of microphytobenthos and used these derived values to better inform the isotopic mixing models. Our results reinforce earlier estimates of the importance of biofilm to staging shorebirds in predicting that assimilated nutrients from biofilm contribute ~35% of the protein budgets for staging western sandpipers (n = 13) and dunlin (n = 11) and at least 41% of the energy budget of western sandpiper (n = 69). Dunlin's ingestion of biofilm appeared higher than anticipated given their expected reliance on invertebrate prey compared to western sandpiper, a biofilm specialist. Isotopic analyses of bulk tissues that consider metabolic routing and that make use of breath CO2 and adipose lipid assays can provide new insights into avian physiology. We advocate further isotopic research to better understand biofilm use by migratory shorebirds in general and as a critical requirement for more effective conservation.}, } @article {pmid35196921, year = {2022}, author = {Zeng, Q and Fu, Y and Yang, M and Wang, T and Wang, Y and Lv, S and Qian, W}, title = {Effect of paeonol against bacterial growth, biofilm formation and dispersal of Staphylococcus aureus and Listeria monocytogenes in vitro.}, journal = {Biofouling}, volume = {38}, number = {2}, pages = {173-185}, doi = {10.1080/08927014.2022.2045014}, pmid = {35196921}, issn = {1029-2454}, mesh = {Acetophenones ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Listeria monocytogenes ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Previous studies have demonstrated the antibacterial activity of paeonol against bacterial pathogens, but its anti-biofilm activities against Staphylococcus aureus and Listeria monocytogenes remain largely unexplored. Here, the antibacterial and anti-biofilm activities of paeonol against S. aureus and L. monocytogenes were examined using the crystal violet staining assay (CVSA), field emission scanning electron microscopy (FESEM), and confocal laser scanning microscopy (CLSM) analysis. Paeonol effectively inhibited the growth of S. aureus and L. monocytogenes with a minimum inhibitory concentration (MIC) of 500 and 125 μg ml[-1], respectively, and disrupted the integrity of cell membranes. Moreover, sub-MIC paeonol exhibited an inhibitory effect on the attachment of S. aureus and L. monocytogenes to the abiotic surface and biofilm formation. Further, paeonol effectively destroyed cell membranes within biofilms, and dispersed mature biofilms of both strains. The results indicate that paeonol might be a promising antibacterial and anti-biofilm agent for combating infections caused by S. aureus and L. monocytogenes.}, } @article {pmid35196798, year = {2022}, author = {Bispo, M and Santos, SB and Melo, LDR and Azeredo, J and van Dijl, JM}, title = {Targeted Antimicrobial Photodynamic Therapy of Biofilm-Embedded and Intracellular Staphylococci with a Phage Endolysin's Cell Binding Domain.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0146621}, pmid = {35196798}, issn = {2165-0497}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Drug Resistance, Multiple, Bacterial ; Endopeptidases/chemistry/metabolism/*pharmacology ; Humans ; Indoles/chemistry ; Light ; Organosilicon Compounds/chemistry ; *Photochemotherapy ; Photosensitizing Agents/chemistry ; Reactive Oxygen Species/metabolism ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus/*drug effects/*physiology/virology ; Staphylococcus Phages/*chemistry/metabolism ; }, abstract = {Bacterial pathogens are progressively adapting to current antimicrobial therapies with severe consequences for patients and global health care systems. This is critically underscored by the rise of methicillin resistant Staphylococcus aureus (MRSA) and other biofilm-forming staphylococci. Accordingly, alternative strategies have been explored to fight such highly multidrug resistant microorganisms, including antimicrobial photodynamic therapy (aPDT) and phage therapy. aPDT has the great advantage that it does not elicit resistance, while phage therapy allows targeting of specific pathogens. In the present study, we aimed to merge these benefits by conjugating the cell-binding domain (CBD3) of a Staphylococcus aureus phage endolysin to a photoactivatable silicon phthalocyanine (IRDye 700DX) for the development of a Staphylococcus-targeted aPDT approach. We show that, upon red-light activation, the resulting CBD3-700DX conjugate generates reactive oxygen species that effectively kill high loads of planktonic and biofilm-resident staphylococci, including MRSA. Furthermore, CBD3-700DX is readily internalized by mammalian cells, where it allows the targeted killing of intracellular MRSA upon photoactivation. Intriguingly, aPDT with CBD3-700DX also affects mammalian cells with internalized MRSA, but it has no detectable side effects on uninfected cells. Altogether, we conclude that CBD3 represents an attractive targeting agent for Staphylococcus-specific aPDT, irrespective of planktonic, biofilm-embedded, or intracellular states of the bacterium. IMPORTANCE Antimicrobial resistance is among the biggest threats to mankind today. There are two alternative antimicrobial therapies that may help to control multidrug-resistant bacteria. In phage therapy, natural antagonists of bacteria, lytic phages, are harnessed to fight pathogens. In antimicrobial photodynamic therapy (aPDT), a photosensitizer, molecular oxygen, and light are used to produce reactive oxygen species (ROS) that inflict lethal damage on pathogens. Since aPDT destroys multiple essential components in targeted pathogens, aPDT resistance is unlikely. However, the challenge in aPDT is to maximize target specificity and minimize collateral oxidative damage to host cells. We now present an antimicrobial approach that combines the best features of both alternative therapies, namely, the high target specificity of phages and the efficacy of aPDT. This is achieved by conjugating the specific cell-binding domain from a phage protein to a near-infrared photosensitizer. aPDT with the resulting conjugate shows high target specificity toward MRSA with minimal side effects.}, } @article {pmid35196793, year = {2022}, author = {Ruiz-Sorribas, A and Poilvache, H and Kamarudin, NHN and Braem, A and Van Bambeke, F}, title = {Hydrolytic Enzymes as Potentiators of Antimicrobials against an Inter-Kingdom Biofilm Model.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0258921}, pmid = {35196793}, issn = {2165-0497}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Bacterial Infections/microbiology ; Biocatalysis ; Biofilms/*drug effects ; Candida albicans/chemistry/*drug effects/physiology ; Candidiasis/microbiology ; Cell Wall/chemistry/drug effects ; Drug Synergism ; Enzymes/chemistry/*pharmacology ; Escherichia coli/chemistry/*drug effects/physiology ; Glucan Endo-1,3-beta-D-Glucosidase/chemistry/pharmacology ; Humans ; Microbial Sensitivity Tests ; Multienzyme Complexes/chemistry/pharmacology ; Peptide Hydrolases/chemistry/pharmacology ; Staphylococcus aureus/chemistry/*drug effects/physiology ; Subtilisins/chemistry/pharmacology ; }, abstract = {Biofilms are recalcitrant to antimicrobials, partly due to the barrier effect of their matrix. The use of hydrolytic enzymes capable to degrade matrix constituents has been proposed as an alternative strategy against biofilm-related infections. This study aimed to determine whether hydrolytic enzymes could potentiate the activity of antimicrobials against hard-to-treat interkingdom biofilms comprising two bacteria and one fungus. We studied the activity of a series of enzymes alone or in combination, followed or not by antimicrobial treatment, against single-, dual- or three-species biofilms of Staphylococcus aureus, Escherichia coli, and Candida albicans, by measuring their residual biomass or culturable cells. Two hydrolytic enzymes, subtilisin A and lyticase, were identified as the most effective to reduce the biomass of C. albicans biofilm. When targeting interkingdom biofilms, subtilisin A alone was the most effective enzyme to reduce biomass of all biofilms, followed by lyticase combined with an enzymatic cocktail composed of cellulase, denarase, and dispersin B that proved previously active against bacterial biofilms. The subsequent incubation with antimicrobials further reduced the biomass. Enzymes alone did not reduce culturable cells in most cases and did not interfere with the cidal effects of antimicrobials. Therefore, this work highlights the potential interest of pre-exposing interkingdom biofilms to hydrolytic enzymes to reduce their biomass besides the number of culturable cells, which was not achieved when using antimicrobials alone. IMPORTANCE Biofilms are recalcitrant to antimicrobial treatments. This problem is even more critical when dealing with polymicrobial, interkingdom biofilms, including both bacteria and fungi, as these microorganisms cooperate to strengthen the biofilm and produce a complex matrix. Here, we demonstrate that the protease subtilisin A used alone, or a cocktail containing lyticase, cellulase, denarase, and dispersin B markedly reduce the biomass of interkingdom biofilms and cooperate with antimicrobials to act upon these recalcitrant forms of infection. This work may open perspectives for the development of novel adjuvant therapies against biofilm-related infections.}, } @article {pmid35196792, year = {2022}, author = {Li, Y and Wang, B and Lu, F and Ahn, J and Zhang, W and Cai, L and Xu, J and Yin, Y and Cao, Q and Ren, Z and He, X}, title = {Synergistic Inhibitory Effect of Polymyxin B in Combination with Ceftazidime against Robust Biofilm Formed by Acinetobacter baumannii with Genetic Deficiency in AbaI/AbaR Quorum Sensing.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0176821}, pmid = {35196792}, issn = {2165-0497}, mesh = {Acinetobacter Infections/drug therapy ; Acinetobacter baumannii/*drug effects/*genetics/growth & development ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Ceftazidime/pharmacology/*therapeutic use ; Drug Resistance, Multiple, Bacterial/drug effects/genetics ; Drug Therapy, Combination/methods ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Polymyxin B/pharmacology/*therapeutic use ; Quorum Sensing/drug effects/*genetics ; beta-Lactamases/genetics ; }, abstract = {Carbapenem resistance of Acinetobacter baumannii poses challenges to public health. Biofilm contributes to the persistence of A. baumannii cells. This study was designed to investigate the genetic relationships among carbapenem resistance, polymyxin resistance, multidrug resistance, biofilm formation, and surface-associated motility and evaluate the antibiofilm effect of polymyxin in combination with other antibiotics. A total of 103 clinical A. baumannii strains were used to determine antibiotic susceptibility, biofilm formation capacity, and motility. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting was used to determine the genetic variation among strains. The distribution of 17 genes related to the resistance-nodulation-cell division (RND)-type efflux, autoinducer-receptor (AbaI/AbaR) quorum sensing, oxacillinases (OXA)-23, and insertion sequence of ISAba1 element was investigated. The representative strains were chosen to evaluate the gene transcription and the antibiofilm activity by polymyxin B (PB) in combination with merapenem, levofloxacin, and ceftazidime, respectively. ERIC-PCR-dependent fingerprints were found to be associated with carbapenem resistance and multidrug resistance. The presence of blaOXA-23 was found to correlate with genes involved in ISAba1 insertion, AbaI/AbaR quorum sensing, and AdeABC efflux. Carbapenem resistance was observed to be negatively correlated with biofilm formation and positively correlated with motility. PB in combination with ceftazidime displayed a synergistic antibiofilm effect against robust biofilm formed by an A. baumannii strain with deficiency in AbaI/AbaR quorum sensing. Our results not only clarify the genetic correlation among carbapenem resistance, biofilm formation, and pathogenicity in a certain level but also provide a theoretical basis for clinical applications of polymyxin-based combination of antibiotics in antibiofilm therapy. IMPORTANCE Deeper explorations of molecular correlation among antibiotic resistance, biofilm formation, and pathogenicity could provide novel insights that would facilitate the development of therapeutics and prevention against A. baumannii biofilm-related infections. The major finding that polymyxin B in combination with ceftazidime displayed a synergistic antibiofilm effect against robust biofilm formed by an A. baumannii strain with genetic deficiency in AbaI/AbaR quorum sensing further provides a theoretical basis for clinical applications of antibiotics in combination with quorum quenching in antibiofilm therapy.}, } @article {pmid35196619, year = {2022}, author = {Wu, C and Zhou, L and Zhou, C and Zhou, Y and Zhou, J and Xia, S and Rittmann, BE}, title = {A kinetic model for 2,4-dichlorophenol adsorption and hydrodechlorination over a palladized biofilm.}, journal = {Water research}, volume = {214}, number = {}, pages = {118201}, doi = {10.1016/j.watres.2022.118201}, pmid = {35196619}, issn = {1879-2448}, abstract = {Adsorption and catalytic hydrodechlorination (HDC) of aqueous 2,4-DCP by palladium nanoparticles (Pd[0]NPs) associated with a biofilm (i.e., a Pd[0]-biofilm) was investigated in terms of the removal efficiency of 2,4-DCP, dechlorinated product selectivity, and reduction kinetics. Experiments were executed with Pd[0]-biofilm and with abiotic Pd[0]NPs-film alone. The 2,4-DCP-adsorption capacity of Pd[0]-biofilm was 2- to 5-fold greater than that of abiotic Pd[0]NPs-film, and the adsorption accelerated dechlorination by Pd[0]-biofilm, including selectivity to phenol instead of mono-chlorophenols. A mechanistic kinetic model was developed to represent the sequential adsorption and reduction processes. Modeling results represented well the removal of 2,4-DCP and quantified that Pd[0]-biofilm had a strong affinity for adsorbing 2,4-DCP. The strong adsorption increased the volume-averaged concentration of 2,4-DCP concentration inside the Pd[0]-biofilm, compared to the concentration in the bulk liquid. This increase in the local concentration of 2,4-DCP led to a 2- to 4-fold increase in the reduction rate of 2,4-DCP in Pd[0]-biofilm, compared to abiotic Pd[0]NPs-film. Thus, coupling Pd[0]NPs with the biofilm promoted 2,4-DCP removal and full dechlorination despite its low concentration in bulk water.}, } @article {pmid35196222, year = {2022}, author = {Sharma, M and Lee, LK and Carson, MD and Park, DS and An, SW and Bovenkamp, MG and Cayetano, JJ and Berude, IA and Nelson, LY and Xu, Z and Sadr, A and Patel, SN and Seibel, EJ}, title = {O-pH: Optical pH Monitor to Measure Dental Biofilm Acidity and Assist in Enamel Health Monitoring.}, journal = {IEEE transactions on bio-medical engineering}, volume = {69}, number = {9}, pages = {2776-2786}, pmid = {35196222}, issn = {1558-2531}, support = {UL1 TR000423/TR/NCATS NIH HHS/United States ; UL1 TR002319/TR/NCATS NIH HHS/United States ; }, mesh = {*Biofilms ; Calibration ; Child ; *Dental Enamel/diagnostic imaging ; Humans ; Hydrogen-Ion Concentration ; }, abstract = {OBJECTIVE: Bacteria in the dental biofilm produceacid after consumption of carbohydrates which if left unmonitored leads to caries formation. We present O-pH, a device that can measure dental biofilm acidity and provide quantitative feedback to assist in oral health monitoring.

METHOD: O-pH utilizes a ratiometric pH sensing method by capturing fluorescence of Sodium Fluorescein, an FDA approved chemical dye. The device was calibrated to a lab pH meter using buffered fluorescein solution with a correlation coefficient of 0.97. The calibration was further verified in vitro on additional buffered solution, artificial, and extracted teeth. An in vivo study on 30 pediatric subjects was performed to measure pH before (rest pH) and after (drop pH) a sugar rinse, and the resultant difference in pH (diff pH) was calculated. The study enrolled subjects with low (Post-Cleaning) and heavy (Pre-Cleaning) biofilm load, having both unhealthy/healthy surfaces. Further, we modified point-based O-pH to an image-based device using a multimode-scanning fiber endoscope (mm-SFE) and tested in vivo on one subject.

RESULTS AND CONCLUSION: We found significant difference between Post-Cleaning and Pre-Cleaning group using drop pH and diff pH. Additionally, in Pre-Cleaning group, the rest and drop pH is lower at the caries surfaces compared to healthy surfaces. Similar trend was not noticed in the Post-Cleaning group. mm-SFE pH scope recorded image-based pH heatmap of a subject with an average diff pH of 1.5.

SIGNIFICANCE: This work builds an optical pH prototype and presents a pioneering study for non-invasively measuring pH of dental biofilm clinically.}, } @article {pmid35195016, year = {2022}, author = {Garcia, CR and Ueda, TY and da Silva, RA and Cano, IP and Saldanha, LL and Dokkedal, AL and Porto, VC and Urban, VM and Neppelenbroek, KH}, title = {Effect of denture liners surface modification with Equisetum giganteum and Punica granatum on Candida albicans biofilm inhibition.}, journal = {Therapeutic delivery}, volume = {13}, number = {3}, pages = {157-166}, doi = {10.4155/tde-2021-0074}, pmid = {35195016}, issn = {2041-6008}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; *Denture Liners ; *Equisetum ; Humans ; Nystatin/pharmacology ; *Pomegranate ; *Stomatitis, Denture/drug therapy ; }, abstract = {Aim: This study investigated the effect of denture liners surface modification with Equisetum giganteum (EG) and Punica granatum (PG) on Candida albicans biofilm inhibition supposing its usage as a sustained-release therapeutical delivery system for Candida-associated denture stomatitis. Materials & methods:C. albicans biofilm (SC5314 or ATCC 90028) was formed on soft liners superficially modified by a primer mixed to drugs at minimum inhibitory concentrations (0.100 g for EG and PG or 0.016 g for nystatin per ml of primer). After 24 h, 7 or 14 days, antibiofilm activity was evaluated by colony-forming unit counts. Results: Not all groups were equi-efficient to nystatin after 24 h and 7 days. After 14 days, EG and PG efficacies were not different from nystatin (almost 100% inhibition). Conclusion: The proposed protocol presents a promising option to allopathic drugs for Candida-associated denture stomatitis treatment.}, } @article {pmid35193209, year = {2022}, author = {Tam, AKY and Harding, B and Green, JEF and Balasuriya, S and Binder, BJ}, title = {Thin-film lubrication model for biofilm expansion under strong adhesion.}, journal = {Physical review. E}, volume = {105}, number = {1-1}, pages = {014408}, doi = {10.1103/PhysRevE.105.014408}, pmid = {35193209}, issn = {2470-0053}, abstract = {Understanding microbial biofilm growth is important to public health because biofilms are a leading cause of persistent clinical infections. In this paper, we develop a thin-film model for microbial biofilm growth on a solid substratum to which it adheres strongly. We model biofilms as two-phase viscous fluid mixtures of living cells and extracellular fluid. The model explicitly tracks the movement, depletion, and uptake of nutrients and incorporates cell proliferation via a nutrient-dependent source term. Notably, our thin-film reduction is two dimensional and includes the vertical dependence of cell volume fraction. Numerical solutions show that this vertical dependence is weak for biologically feasible parameters, reinforcing results from previous models in which this dependence was neglected. We exploit this weak dependence by writing and solving a simplified one-dimensional model that is computationally more efficient than the full model. We use both the one- and two-dimensional models to predict how model parameters affect expansion speed and biofilm thickness. This analysis reveals that expansion speed depends on cell proliferation, nutrient availability, cell-cell adhesion on the upper surface, and slip on the biofilm-substratum interface. Our numerical solutions provide a means to qualitatively distinguish between the extensional flow and lubrication regimes, and quantitative predictions that can be tested in future experiments.}, } @article {pmid35192804, year = {2022}, author = {Wu, H and Li, A and Wang, J and Li, X and Cui, M and Yang, N and Liu, Y and Zhang, L and Wang, X and Zhan, G}, title = {A novel electrochemical sensor based on autotropic and heterotrophic nitrifying biofilm for trichloroacetic acid toxicity monitoring.}, journal = {Environmental research}, volume = {210}, number = {}, pages = {112985}, doi = {10.1016/j.envres.2022.112985}, pmid = {35192804}, issn = {1096-0953}, mesh = {Biofilms ; Bioreactors ; *Nitrification ; Nitrogen/metabolism ; Oxygen ; *Trichloroacetic Acid ; Water ; }, abstract = {Trichloroacetic acid (TCA), a toxic substance produced in the disinfection process of wastewater treatment plants, will accumulate in the receiving water. The detection of TCA in the water can achieve the purpose of early warning. However, currently there are few reports on microbial sensors used for TCA detection, and the characteristics of their microbial communities are still unclear. In this work, a toxicity monitoring microbial system (TMMS) with nitrifying biofilm as a sensing element and cathode oxygen reduction as a current signal was successfully constructed for TCA detection. The current and nitrification rate showed a linear relationship with low TCA concentration from 0 to 50 μg/L (R[2]current = 0.9892, R[2]nitrification = 0.9860), and high concentration range from 50 to 5000 μg/L (R[2]current = 0.9883, R[2]nitrification = 0.9721). High-throughput sequencing revealed that the TMMS was composed of autotrophic/heterotrophic nitrifying and denitrifying microorganisms. Further analysis via symbiotic relationship network demonstrated that Arenimonas and Hyphomicrobium were the core nodes for maintaining interaction between autotropic and heterotrophic nitrifying bacteria. Kyoto Encyclopedia of Genes and Genomes analysis showed that after adding TCA to TMMS, the carbon metabolism and the abundance of the tricarboxylic acid cycle pathway were reduced, and the activity of microorganisms was inhibited. TCA stress caused a low abundance of nitrifying and denitrifying functional enzymes, resulting in low oxygen consumption in the nitrification process, but more oxygen supply for cathode oxygen reduction. This work explored a novel sensor combined with electrochemistry and autotrophic/heterotrophic nitrification, which provided a new insight into the development of microbial monitoring of toxic substances.}, } @article {pmid35192095, year = {2022}, author = {Vo, LK and Tran, NT and Kubo, Y and Sahashi, D and Komatsu, M and Shiozaki, K}, title = {Enhancement of Edwardsiella piscicida infection, biofilm formation, and motility caused by N-acetylneuraminate lyase.}, journal = {Glycoconjugate journal}, volume = {39}, number = {3}, pages = {429-442}, pmid = {35192095}, issn = {1573-4986}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Edwardsiella ; *N-Acetylneuraminic Acid/metabolism ; Oxo-Acid-Lyases ; *Zebrafish ; }, abstract = {Sialic acid and its catabolism are involved in bacterial pathogenicity. N-acetylneuraminate lyase (NAL), which catalyzes the reversible aldol cleavage of sialic acid to form N-acetyl-D-mannosamine in the first step of sialic acid degradation, has been recently investigated to elucidate whether NAL enhances bacterial virulence; however, the role of NAL in bacterial pathogenicity remains unclear. In the present study, we demonstrated that the existence of two enzymes in Edwardsiella piscicida, referred to as dihydrodipicolinate synthase (DHDPS) and NAL, induced the cleavage/condensation activity toward sialic acids such as N-acetylneuraminic acid, N-glycolylneuraminic acid and 3-deoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid. NAL enhanced cellular infection in vitro and suppressed the survival rate in zebrafish larvae in bath-infection in vivo, whereas DHDPS did not. Furthermore, NAL strongly activated the expression of E. piscicida phenotypes such as biofilm formation and motility, whereas DHDPS did not. Besides, the gene expression level of nanK, nanE, and glmU were up-regulated in the NAL-overexpressing strain, along with an increase in the total amount of N-acetylglucosamine.}, } @article {pmid35191778, year = {2022}, author = {Schulze, S and Schiller, H and Solomonic, J and Telhan, O and Costa, K and Pohlschroder, M}, title = {Advanced Understanding of Prokaryotic Biofilm Formation through Use of a Cost-Effective and Versatile Multipanel Adhesion (mPAD) Mount.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {4}, pages = {e0228321}, pmid = {35191778}, issn = {1098-5336}, mesh = {*Biofilms ; Cost-Benefit Analysis ; Haloferax volcanii ; *Microbiological Techniques/methods ; *Prokaryotic Cells/physiology ; Pseudomonas aeruginosa ; }, abstract = {Most microorganisms exist in biofilms, which comprise aggregates of cells surrounded by an extracellular matrix that provides protection from external stresses. Based on the conditions under which they form, biofilm structures vary in significant ways. For instance, biofilms that develop when microbes are incubated under static conditions differ from those formed when microbes encounter the shear forces of a flowing liquid. Moreover, biofilms develop dynamically over time. Here, we describe a cost-effective coverslip holder, printed with a three-dimensional (3D) printer, that facilitates surface adhesion assays under a broad range of standing and shaking culture conditions. This multipanel adhesion (mPAD) mount further allows cultures to be sampled at multiple time points, ensuring consistency and comparability between samples and enabling analyses of the dynamics of biofilm formation. As a proof of principle, using the mPAD mount for shaking, oxic cultures, we confirm previous flow chamber experiments showing that the Pseudomonas aeruginosa wild-type strain and a phenazine deletion mutant (Δphz) strain form biofilms with similar structure but reduced density in the mutant strain. Extending this analysis to anoxic conditions, we reveal that microcolony formation and biofilm formation can only be observed under shaking conditions and are decreased in the Δphz mutant compared to wild-type cultures, indicating that phenazines are crucial for the formation of biofilms if oxygen as an electron acceptor is unavailable. Furthermore, while the model archaeon Haloferax volcanii does not require archaella for surface attachment under static conditions, we demonstrate that an H. volcanii mutant that lacks archaella is impaired in early stages of biofilm formation under shaking conditions. IMPORTANCE Due to the versatility of the mPAD mount, we anticipate that it will aid the analysis of biofilm formation in a broad range of bacteria and archaea. Thereby, it contributes to answering critical biological questions about the regulatory and structural components of biofilm formation and understanding this process in a wide array of environmental, biotechnological, and medical contexts.}, } @article {pmid35190278, year = {2022}, author = {Latorre, MC and Alcalá, L and Castellano, M and Lasso, J and Pérez-Cano, R and Bouza, E and Muñoz, P and Guembe, M}, title = {The role of biofilm production in Cutibacterium acnes strains isolated from breast implants.}, journal = {Journal of plastic, reconstructive & aesthetic surgery : JPRAS}, volume = {75}, number = {5}, pages = {1765-1779}, doi = {10.1016/j.bjps.2021.08.014}, pmid = {35190278}, issn = {1878-0539}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; Humans ; Propionibacterium acnes ; }, abstract = {The role of C. acnes biofilm production in the pathogenesis of breast implants infections has not been deeply assessed. We analyze biofilm production (in terms of biomass and metabolic activity) between 40 Cutibacterium acnes strains isolated from breast implants and 32 from other sites. C. acnes strains isolated from breast implants showed higher metabolic activity than those isolated from other-locations and, especially, those from patients with capsular contracture .}, } @article {pmid35189700, year = {2022}, author = {Simon-Soro, A and Ren, Z and Krom, BP and Hoogenkamp, MA and Cabello-Yeves, PJ and Daniel, SG and Bittinger, K and Tomas, I and Koo, H and Mira, A}, title = {Polymicrobial Aggregates in Human Saliva Build the Oral Biofilm.}, journal = {mBio}, volume = {13}, number = {1}, pages = {e0013122}, pmid = {35189700}, issn = {2150-7511}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; 834.13.006//NWO Earth and Life Sciences (ALW)/ ; BIO2015-68711-R//Spanish Ministry of Economy and Competitiveness/ ; }, mesh = {Bacteria ; Biofilms ; *Ecosystem ; Humans ; Phylogeny ; *Saliva/microbiology ; }, abstract = {Biofilm community development has been established as a sequential process starting from the attachment of single cells on a surface. However, microorganisms are often found as aggregates in the environment and in biological fluids. Here, we conduct a comprehensive analysis of the native structure and composition of aggregated microbial assemblages in human saliva and investigate their spatiotemporal attachment and biofilm community development. Using multiscale imaging, cell sorting, and computational approaches combined with sequencing analysis, a diverse mixture of aggregates varying in size, structure, and microbial composition, including bacteria associated with host epithelial cells, can be found in saliva in addition to a few single-cell forms. Phylogenetic analysis reveals a mixture of complex consortia of aerobes and anaerobes in which bacteria traditionally considered early and late colonizers are found mixed together. When individually tracked during colonization and biofilm initiation, aggregates rapidly proliferate and expand tridimensionally, modulating population growth, spatial organization, and community scaffolding. In contrast, most single cells remain static or are incorporated by actively growing aggregates. These results suggest an alternative biofilm development process whereby aggregates containing different species or associated with human cells collectively adhere to the surface as "growth nuclei" to build the biofilm and shape polymicrobial communities at various spatial and taxonomic scales. IMPORTANCE Microbes in biological fluids can be found as aggregates. How these multicellular structures bind to surfaces and initiate the biofilm life cycle remains understudied. Here, we investigate the structural organization of microbial aggregates in human saliva and their role in biofilm formation. We found diverse mixtures of aggregates with different sizes, structures, and compositions in addition to free-living cells. When individually tracked during binding and growth on tooth-like surfaces, most aggregates developed into structured biofilm communities, whereas most single cells remained static or were engulfed by the growing aggregates. Our results reveal that preformed microbial consortia adhere as "buds of growth," governing biofilm initiation without specific taxonomic order or cell-by-cell succession, which provide new insights into spatial and population heterogeneity development in complex ecosystems.}, } @article {pmid35186780, year = {2021}, author = {Zaborskytė, G and Wistrand-Yuen, E and Hjort, K and Andersson, DI and Sandegren, L}, title = {Modular 3D-Printed Peg Biofilm Device for Flexible Setup of Surface-Related Biofilm Studies.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {802303}, pmid = {35186780}, issn = {2235-2988}, mesh = {*Biofilms ; *Escherichia coli ; Klebsiella pneumoniae ; Microscopy, Electron, Scanning ; Printing, Three-Dimensional ; }, abstract = {Medical device-related biofilms are a major cause of hospital-acquired infections, especially chronic infections. Numerous diverse models to study surface-associated biofilms have been developed; however, their usability varies. Often, a simple method is desired without sacrificing throughput and biological relevance. Here, we present an in-house developed 3D-printed device (FlexiPeg) for biofilm growth, conceptually similar to the Calgary Biofilm device but aimed at increasing ease of use and versatility. Our device is modular with the lid and pegs as separate units, enabling flexible assembly with up- or down-scaling depending on the aims of the study. It also allows easy handling of individual pegs, especially when disruption of biofilm populations is needed for downstream analysis. The pegs can be printed in, or coated with, different materials to create surfaces relevant to the study of interest. We experimentally validated the use of the device by exploring the biofilms formed by clinical strains of Escherichia coli and Klebsiella pneumoniae, commonly associated with device-related infections. The biofilms were characterized by viable cell counts, biomass staining, and scanning electron microscopy (SEM) imaging. We evaluated the effects of different additive manufacturing technologies, 3D printing resins, and coatings with, for example, silicone, to mimic a medical device surface. The biofilms formed on our custom-made pegs could be clearly distinguished based on species or strain across all performed assays, and they corresponded well with observations made in other models and clinical settings, for example, on urinary catheters. Overall, our biofilm device is a robust, easy-to-use, and relevant assay, suitable for a wide range of applications in surface-associated biofilm studies, including materials testing, screening for biofilm formation capacity, and antibiotic susceptibility testing.}, } @article {pmid35185832, year = {2021}, author = {Song, Y and Ma, F and Sun, M and Mu, G and Tuo, Y}, title = {The Chemical Structure Properties and Promoting Biofilm Activity of Exopolysaccharide Produced by Shigella flexneri.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {807397}, pmid = {35185832}, issn = {1664-302X}, abstract = {Shigella flexneri is a waterborne and foodborne pathogen that can damage human health. The exopolysaccharides (S-EPS) produced by S. flexneri CMCC51574 were found to promote biofilm formation and virulence. In this research, the crude S-EPS produced by S. flexneri CMCC51574 were separated into three main different fractions, S-EPS 1-1, S-EPS 2-1, and S-EPS 3-1. The structure of the S-ESP 2-1 was identified by FT-IR, ion chromatography analysis, methylation analysis, and NMR analysis. The main chain of S-EPS 2-1 was α-Manp-(1 → 3)-α-Manp-[(1 → 2,6)-α-Manp]15-[(1 → 2)-Manf-(1→]8; there were two branched-chain R1 and R2 with a ratio of 4:1, R1: α-Manp-(1 → 6)- and R2: α-Manp-(1 → 6)- Glc-(1 → 6)- were linked with (1 → 2,6)-α-Manp. It was found that S-EPS 2-1 exhibited the highest promoting effect on biofilm formation of S. flexneri. The S-EPS 2-1 was identified to interact with extracellular DNA (eDNA) of S. flexneri, indicating that the S-EPS 2-1 was the specific polysaccharide in the spatial structure of biofilm formation. Our research found the important role of S-EPS in S. flexneri biofilm formation, which will help us to understand the underlining mechanisms of the biofilm formation and find effective ways to prevent S. flexneri biofilm infection.}, } @article {pmid35185813, year = {2021}, author = {Peng, Z and Tang, J}, title = {Intestinal Infection of Candida albicans: Preventing the Formation of Biofilm by C. albicans and Protecting the Intestinal Epithelial Barrier.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {783010}, pmid = {35185813}, issn = {1664-302X}, abstract = {The large mortality and morbidity rate of C. albicans infections is a crucial problem in medical mycology. Because the generation of biofilms and drug resistance are growing concerns, the growth of novel antifungal agents and the looking for newer objectives are necessary. In this review, inhibitors of C. albicans biofilm generation and molecular mechanisms of intestinal epithelial barrier protection are elucidated. Recent studies on various transcription elements; quorum-sensing molecules; host responses to adherence; and changes in efflux pumps, enzymes, bud to hyphal transition, and lipid profiles have increased the knowledge of the intricate mechanisms underlying biofilm resistance. In addition, the growth of novel biomaterials with anti-adhesive nature, natural products, drugs, bioactive compounds, proteins, lipids, and carbohydrates are being researched. Recently, more and more attention has been given to various metal nanoparticles that have also appeared as antibiofilm agents in C. albicans. The intestinal epithelial obstacle exerts an crucial effect on keeping intestinal homeostasis and is increasingly associated with various disorders associated with the intestine such as inflammatory bowel disease (IBD), irritable bowel syndrome, metabolic syndrome, allergies, hepatic inflammation, septic shock, etc. However, whether their involvement in the prevention of other intestinal disorders like IBD are useful in C. albicans remains unknown. Further studies must be carried out in order to validate their inhibition functions in intestinal C. albicans. This provides innovates ideas for intestinal C. albicans treatment.}, } @article {pmid35184449, year = {2022}, author = {She, PF and Xu, LL and Liu, YQ and Li, ZH and Liu, SS and Li, YM and Zhou, LY and Wu, Y}, title = {[Perifosine inhibits biofilm formation of Pseudomonas aeruginosa by interacting with PqsE protein].}, journal = {Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]}, volume = {56}, number = {2}, pages = {192-196}, doi = {10.3760/cma.j.cn112150-20211020-00970}, pmid = {35184449}, issn = {0253-9624}, support = {82072350//National Natural Science Foundation of China/ ; 2021JJ40944//Natural Science Foundation of Hunan Province/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Molecular Docking Simulation ; Phosphorylcholine/analogs & derivatives ; *Pseudomonas aeruginosa/metabolism ; *Quorum Sensing ; }, abstract = {To explore the biofilm inhibitory efficacy of perifosine against Pseudomonas aeruginosa (P. aeruginos) and its mechanisms. Twenty-fourwell plate was used to form biofilms at the bottom and crystal violet staining was used to determine the biofilm inhibitory effects of perifosine against P. aeruginosa, the wells without perifosine was set as control group. Glass tubes combined with crystal violet staining was used to detect the gas-liqud interface related bioiflm inhibitory effects of perifosine, the wells without perifosine was set as control group. Time-growth curved was used to detect the effects of perifosine on the bacteial planktonic cells growth of P. aeruginosa, the wells without perifosine was set as control group. The interaction model between perifosine and PqsE was assessed by molecular docking assay. The inhibitory effects of perifosine on the catalytic activity of PqsE was determined by detection the production of thiols, the wells without perifosine was set as control group. Binding affinity between perifosine and PqsE was detected by plasma surface resonance. The biofims at the bottom of the microplates and air-liquid interface were effectively inhibited by perifosine at the concentration of 4-8 μg/ml. There was no influence of perifosine on the cells growth of P. aeruginosa. The resuts of molecular docking assay indicates that perifosine could interacted with PqsE with the docking score of -10.67 kcal/mol. Perifosine could inhibit the catalytic activity of PqsE in a dose-dependent manner. The binding affinity between perifosine and PqsE was comfirmed by plasma surface resonance with KD of 6.65×10[-5]mol/L. Perifosine could inhibited the biofilm formation of P. aeruginosa by interacting with PqsE.}, } @article {pmid35183018, year = {2022}, author = {Tian, L and Yan, X and Wang, D and Du, Q and Wan, Y and Zhou, L and Li, T and Liao, C and Li, N and Wang, X}, title = {Two key Geobacter species of wastewater-enriched electroactive biofilm respond differently to electric field.}, journal = {Water research}, volume = {213}, number = {}, pages = {118185}, doi = {10.1016/j.watres.2022.118185}, pmid = {35183018}, issn = {1879-2448}, abstract = {Electroactive biofilms have attracted increasing attention due to their unique ability to exchange electrons with electrodes. Geobacter spp. are widely found to be dominant in biofilms in acetate-rich environments when an appropriate voltage is applied, but it is still largely unknown how these bacteria are selectively enriched. Herein, two key Geobacter spp. that have been demonstrated predominant in wastewater-enriched electroactive biofilm after long-term operation, G. sulfurreducens and G. anodireducens, responded to electric field (EF) differently, leading to a higher abundance of EF-sensitive G. anodireducens in the strong EF region after cocultivation with G. sulfurreducens. Transcriptome analysis indicated that two-component systems containing sensor histidine kinases and response regulators were the key for EF sensing in G. anodireducens rather than in G. sulfurreducens, which are closely connected to chemotaxis, c-di-GMP, fatty acid metabolism, pilus, oxidative phosphorylation and transcription, resulting in an increase in extracellular polymeric substance secretion and rapid cell proliferation. Our data reveal the mechanism by which EF select specific Geobacter spp. over time, providing new insights into Geobacter biofilm formation regulated by electricity.}, } @article {pmid35182778, year = {2022}, author = {Shim, SH and Lee, SY and Lee, JB and Chang, BS and Lee, JK and Um, HS}, title = {Antimicrobial photothermal therapy using diode laser with indocyanine green on Streptococcus gordonii biofilm attached to zirconia surface.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {38}, number = {}, pages = {102767}, doi = {10.1016/j.pdpdt.2022.102767}, pmid = {35182778}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Indocyanine Green/pharmacology ; Lasers, Semiconductor ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Photothermal Therapy ; Streptococcus gordonii ; Zirconium ; }, abstract = {PURPOSE: The purpose of this study was to evaluate the antimicrobial effects of photothermal therapy using indocyanine green (ICG) and an 810-nm infrared diode laser on Streptococcus gordonii biofilm attached to zirconia surfaces in vitro.

METHODS: A biofilm was formed using the static method on zirconia disks placed in a 24-well plate. The biofilms were subdivided into the following six treatment groups: control, commercial photodynamic therapy (PDT), chlorhexidine gluconate (CHX), laser only (L, 810-nm infrared diode), ICG, and laser with ICG (PTT). After treatment, each disk was agitated and the solution with detached bacteria was spread directly on a blood agar plate. Cells were cultured under anaerobic conditions and colony-forming units were counted. Confocal laser-scanning microscopy was used to assess the survival according to the height of the biofilm.

RESULTS: The PTT, PDT, and CHX groups showed a significant reduction in S. gordonii viability (p<0.05), while the L and ICG groups showed no significant difference compared to the control group (p = 0.32, p = 0.97; respectively). In confocal laser-scanning microscopy images, the PTT, PDT, and CHX groups presented most of the dead bacteria in both the upper and lower levels of biofilm.

CONCLUSION: Within the limitations of this in vitro study, PTT with ICG was effective in significantly reducing the viability of S. gordonii bacteria on zirconia. Further studies are needed to establish a standardized PTT protocol to treat peri‑implant diseases.}, } @article {pmid35181829, year = {2022}, author = {Ford, N and Fisher, G and Prindle, A and Chopp, D}, title = {Correction to: A Two-Dimensional Model of Potassium Signaling and Oscillatory Growth in a Biofilm.}, journal = {Bulletin of mathematical biology}, volume = {84}, number = {4}, pages = {45}, doi = {10.1007/s11538-022-01003-9}, pmid = {35181829}, issn = {1522-9602}, } @article {pmid35181739, year = {2022}, author = {Liew, KJ and Liang, CH and Lau, YT and Yaakop, AS and Chan, KG and Shahar, S and Shamsir, MS and Goh, KM}, title = {Thermophiles and carbohydrate-active enzymes (CAZymes) in biofilm microbial consortia that decompose lignocellulosic plant litters at high temperatures.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {2850}, pmid = {35181739}, issn = {2045-2322}, mesh = {Archaea/enzymology/genetics ; Bacteria/chemistry/genetics ; Biodiversity ; *Biofilms ; Carbohydrates/*chemistry ; Glycoside Hydrolases/chemistry ; Hot Temperature ; Lignin/*chemistry ; Metagenome/genetics ; Microbial Consortia/*genetics ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The SKY hot spring is a unique site filled with a thick layer of plant litter. With the advancement of next-generation sequencing, it is now possible to mine many new biocatalyst sequences. In this study, we aimed to (i) identify the metataxonomic of prokaryotes and eukaryotes in microbial mats using 16S and 18S rRNA markers, (ii) and explore carbohydrate degrading enzymes (CAZymes) that have a high potential for future applications. Green microbial mat, predominantly photosynthetic bacteria, was attached to submerged or floating leaves litter. At the spring head, the sediment mixture consisted of plant debris, predominantly brownish-reddish gelatinous microbial mat, pale tan biofilm, and grey-white filament biofilm. The population in the spring head had a higher percentage of archaea and hyperthermophiles than the green mat. Concurrently, we cataloged nearly 10,000 sequences of CAZymes in both green and brown biofilms using the shotgun metagenomic sequencing approach. These sequences include β-glucosidase, cellulase, xylanase, α-N-arabinofuranosidase, α-L-arabinofuranosidase, and other CAZymes. In conclusion, this work elucidated that SKY is a unique hot spring due to its rich lignocellulosic material, often absent in other hot springs. The data collected from this study serves as a repository of new thermostable macromolecules, in particular families of glycoside hydrolases.}, } @article {pmid35181526, year = {2022}, author = {Vaze, N and Demokritou, P}, title = {Using engineered water nanostructures (EWNS) for wound disinfection: Case study of Acinetobacter baumannii inactivation on skin and the inhibition of biofilm formation.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {42}, number = {}, pages = {102537}, doi = {10.1016/j.nano.2022.102537}, pmid = {35181526}, issn = {1549-9642}, mesh = {*Acinetobacter baumannii ; Animals ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Disinfection ; *Nanostructures/chemistry ; Stainless Steel/pharmacology ; Swine ; Water ; }, abstract = {Engineered water nanostructures (EWNS) were utilized to deliver a cocktail of nature derived antimicrobials, to assess their efficacy as a solution to the problem of wound infections. The wound related microorganism Acinetobacter baumannii was inoculated on stainless steel and porcine skin and treated with EWNS. EWNS were able to reduce A. baumannii on stainless steel by 4.79 logs in 15 min, and 2 logs in 30 min on porcine skin. The EWNS were able to reduce the strength of A. baumannii biofilm on stainless steel by 87.31% as measured with the XTT assay (P < .001) and 86.27% in cellular counts (P < .001), after two EWNS interventions of 30 min each. Total antimicrobial dose delivered to the surface was 1.42 ng. SEM of biofilms after EWNS treatment showed reduced biomass. These results indicate that the EWNS technology has potential for application in field of wound disinfection and healing.}, } @article {pmid35181486, year = {2022}, author = {Wang, T and Song, Y and Xu, H and Liu, Y and He, H and Zhou, M and Jin, C and Yang, M and Ai, Z and Su, D}, title = {Study on the mechanism of reducing biofilm toxicity and increasing antioxidant activity in vinegar processing phytomedicines containing pentacyclic triterpenoid saponins.}, journal = {Journal of ethnopharmacology}, volume = {290}, number = {}, pages = {115112}, doi = {10.1016/j.jep.2022.115112}, pmid = {35181486}, issn = {1872-7573}, mesh = {Acetic Acid/*chemistry ; Antioxidants/pharmacology ; Bupleurum/chemistry ; Pentacyclic Triterpenes/*chemistry ; Pulsatilla/chemistry ; Saponins/*chemistry ; Tandem Mass Spectrometry ; }, abstract = {Pentacyclic triterpenoid saponin (PTS) is a kind of particular chemicals with various pharmacological activities, as well as surface activity, mucosal irritation and hemolysis. PTS is closely related to the exertion of efficacy or adverse reactions in plant medicines rich in this component. For the better clinical application of natural resources, how to reduce toxicity and enhance curative efficacy is an important problem which needs to be solved at present. Till now, there has been few studies directly investigating the problem.

AIM OF STUDY: Through comparison study of Radix Bupleuri (Chai hu) and Pulsatilla chinensis (Bai tou weng), which are typical traditional Chinese medicines containing PTS, explore the potential change rule of material basis and the mechanism of detoxification and synergistic effect of vinegar processing.

MATERIALS AND METHODS: Composition change rule after vinegar processing was applied by UPLC-QTOF-MS/MS coupled with principal component analysis (PCA). Based on our previous research, this paper expounded the action mechanism from the perspective of reducing biofilm toxicity and increasing antioxidant activity. Direct toxicity reducing information was obtained at the cellular level including cellular morphology, MTT assays, western blots and RT-PCR in L02 cells with overload sphingomyelin (SM). The synergistic effect was investigated through histological examinations, mesenteric hemorheology, ELISA, flow cytometry and confocal microscopy.

RESULTS: It was found that the structure of PTS take place a series of chemical reactions in the process of vinegar processing which enabled the more toxic components transformed into less toxic components and components with clear efficacy, so as to achieve the purpose of detoxification and synergistic effect. The results indicated that the mechanism of detoxification in vinegar processing was that vinegar processing could act on SM, cause less balance disturbance to sphingomyelin/ceramide (SM/Cer), inhibit apoptosis and then alleviate toxicity. In addition, the pharmacodynamic results showed that the vinegar processing could have an obvious synergistic effect through anti-oxidant stress.

CONCLUSIONS: By changing the structures of the PTS, the SM/Cer disrupt was reduced and the antioxidant activity was enhanced, so as to decrease toxicity and increase efficiency in vinegar processing phytomedicines containing PTS.}, } @article {pmid35181104, year = {2022}, author = {Fernández-Gómez, P and Muro-Fraguas, I and Múgica-Vidal, R and Sainz-García, A and Sainz-García, E and González-Raurich, M and Álvarez-Ordóñez, A and Prieto, M and López, M and López, M and Toledano, P and Sáenz, Y and González-Marcos, A and Alba-Elías, F}, title = {Development and characterization of anti-biofilm coatings applied by Non-Equilibrium Atmospheric Plasma on stainless steel.}, journal = {Food research international (Ottawa, Ont.)}, volume = {152}, number = {}, pages = {109891}, doi = {10.1016/j.foodres.2020.109891}, pmid = {35181104}, issn = {1873-7145}, mesh = {Biofilms ; Food Microbiology ; Food-Processing Industry ; *Listeria monocytogenes ; *Stainless Steel ; }, abstract = {Biofilm-mediated microbial persistence of pathogenic and spoilage bacteria is a serious problem in food industries. Due to the difficulty of removing mature biofilms, great efforts are being made to find new strategies to prevent bacterial adherence to surfaces, the first step for biofilm development. In this study, coatings of (3-aminopropyl)triethoxysilane (APTES), tetraethyl orthosilicate (TEOS) and acrylic acid (AA) were applied by Non-Equilibrium Atmospheric Plasma on stainless steel (SS) AISI 316, the SS most commonly used in food industry equipment. Their anti-biofilm activity was assessed against Listeria monocytogenes CECT911 and Escherichia coli CECT515 after incubation at 37 °C. The best results were obtained for L. monocytogenes, with coatings consisting of a base coating of APTES and a functional coating of TEOS (AP10 + TE6) or AA (AP10 + AA6) that reduced biofilm production by 45% and 74%, respectively, when compared with the uncoated SS. These coatings were further characterized, together with a variation of the best one that replaced the acrylic acid with succinic acid (AP10 + SA6). Their anti-biofilm activity was assessed under different incubation conditions, including two strains of L. monocytogenes isolated from processing environments of a meat industry. The coating AP10 + AA6 reduced the biofilm formation by 90% after incubation at 12 °C, a temperature more representative of those commonly found in food processing environments. The morphological and physico-chemical characterization of the selected coatings showed that the coating with the highest anti-biofilm activity (i.e., AP10 + AA6) had lower surface roughness and higher hydrophilicity. This suggests that the formation of a hydration layer prevents the adherence of L. monocytogenes, an effect that seems to be enhanced by low temperature conditions, when the wettability of the strains is increased.}, } @article {pmid35181092, year = {2022}, author = {Fernandes, S and Gomes, IB and Simões, M}, title = {Antibiofilm activity of glycolic acid and glyoxal and their diffusion-reaction interactions with biofilm components.}, journal = {Food research international (Ottawa, Ont.)}, volume = {152}, number = {}, pages = {110921}, doi = {10.1016/j.foodres.2021.110921}, pmid = {35181092}, issn = {1873-7145}, mesh = {Biofilms ; *Disinfectants/pharmacology ; Glycolates ; *Glyoxal/pharmacology ; Peracetic Acid/pharmacology ; }, abstract = {Biofilms on food-contact surfaces act as potential reservoirs of microbial pathogens and can cause operational problems. The search for effective biofilm control agents is a significant research need. In this study, glycolic acid (GA) and glyoxal (GO) were tested in the control of biofilms formed by Bacilluscereus and Pseudomonasfluorescens. Benzalkonium chloride (BAC) and peracetic acid (PAA) were used as reference biocides for industrial surface disinfection. The action of the selected biocides was assessed in bacterial motility, culturability, biofilm removal and inactivation, interference with biofilm components and limitation of biocide penetration through the biofilms (reaction-diffusion interactions). Bacterial motility was not affected by the exposure to sub-inhibitory biocide concentrations. In terms of antibiofilm activity, B.cereus biofilms were tolerant to the action of BAC, GA, and GO, with reductions of circa 2-log CFU/cm[2]. Even 10000 µg/mL of PAA had modest effects against B. cereus biofilms (5-log CFU/cm[2]). On the other hand, P.fluorescens biofilms were more susceptible to the biocides, except BAC which was not effective. The minimum concentrations to cause 3-log CFU/cm[2] reduction in P. fluorescens biofilms were 10000 µg/mL of PAA and GA, and 20000 µg/mL of GO. GO and BAC were the most actives for biofilm removal, while high biofilm inactivation was caused by GA and PAA. In general, biofilm components affected the antimicrobial activity of all the biocides. The activity of GA and GO was not notably diffusion-reaction limited in contrast to PAA. Overall, this study demonstrated that GA and GO had potential antibiofilm activity, being limited at a low level by physicochemical interactions with biofilm components.}, } @article {pmid35181068, year = {2022}, author = {von Hertwig, AM and Prestes, FS and Nascimento, MS}, title = {Biofilm formation and resistance to sanitizers by Salmonella spp. Isolated from the peanut supply chain.}, journal = {Food research international (Ottawa, Ont.)}, volume = {152}, number = {}, pages = {110882}, doi = {10.1016/j.foodres.2021.110882}, pmid = {35181068}, issn = {1873-7145}, mesh = {*Arachis ; Biofilms ; Colony Count, Microbial ; *Disinfectants/pharmacology ; Salmonella ; }, abstract = {Pathogens such as Salmonella can be difficult to control in low-moisture food (LMF) processing plants and because of this its presence especially in biofilm mode should be prevented in such an environment. This study evaluated the capacity of Salmonellastrains isolated from the peanut supply chain (S. Muenster, S. Miami, S. Glostrup, S. Javiana, S. Oranienburg and S. Yoruba) to form biofilm as well as their resistance to sanitizers (sodium hypochlorite, peracetic acid, quaternary ammonium, alkaline chlorinated solution and biguanide). Regarding biofilm formation, there was no significant difference (p > 0.05) among the strains tested singly on AISI 304 stainless steel (SS) and polypropylene (PP) coupons at the same temperature. However, a difference (p < 0.05) between the temperatures was noted in the first hours of incubation. The sessile cells reached counts between 3 and 4 log CFU/cm[2] at 25 °C whereas>5 log CFU/cm[2] was observed at 37 °C after 8 h. From 24 h the counts were above 6 log CFU/cm[2] for both temperatures. Nevertheless, the SEM images of the 6-strain pool showed the highest density of adhered cells after 48 h at 25 °C and 24 h at 37 °C on PP, and after 48 h at both temperatures on SS. Peracetic acid (300 mg/L) had the shortest action time against 24-h biofilm on SS and PP, with sessile cell counts below the limit of detection (0.59 log CFU/cm[2]) after 3 min. For 48-h and 96-h biofilm, sodium hypochlorite (200 mg/L) decreased>4 log CFU/cm[2] within 5 min. Quaternary ammonium (350 mg/L) and chlorinated alkaline detergent (200 mg/L) showed intermediate performances. Only biguanide (800 mg/L) did not reduce the biofilm counts to below the limit of detection in any of the conditions evaluated. The results indicated high biofilm formation ability of the Salmonella strains isolated from the peanut supply chain. Nevertheless, in general the biofilms were sensitive to most sanitizers within 15 min of treatment. This was the first study which evaluated biofilm formation by Salmonella isolated from the peanut supply chain. Data obtained here will contribute to optimize the hygiene practices in LMF manufacturing plants.}, } @article {pmid35180519, year = {2022}, author = {Luo, H and Liu, C and He, D and Xu, J and Sun, J and Li, J and Pan, X}, title = {Response to the comments on "Environmental behaviors of microplastics in aquatic systems: A systematic review on degradation, adsorption, toxicity and biofilm under aging conditions".}, journal = {Journal of hazardous materials}, volume = {430}, number = {}, pages = {128344}, doi = {10.1016/j.jhazmat.2022.128344}, pmid = {35180519}, issn = {1873-3336}, mesh = {Adsorption ; Biofilms ; *Microplastics/toxicity ; Plastics/toxicity ; *Water Pollutants, Chemical/analysis/toxicity ; }, } @article {pmid35178858, year = {2022}, author = {Nie, H and Xiao, Y and Song, M and Wu, N and Peng, Q and Duan, W and Chen, W and Huang, Q}, title = {Wsp system oppositely modulates antibacterial activity and biofilm formation via FleQ-FleN complex in Pseudomonas putida.}, journal = {Environmental microbiology}, volume = {24}, number = {3}, pages = {1543-1559}, doi = {10.1111/1462-2920.15905}, pmid = {35178858}, issn = {1462-2920}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial ; *Pseudomonas putida/metabolism ; Trans-Activators/genetics ; }, abstract = {Type VI secretion systems (T6SS) are specific antibacterial weapons employed by diverse bacteria to protect themselves from competitors. Pseudomonas putida KT2440 possesses a functional T6SS (K1-T6SS) and exhibits antibacterial activity towards a broad range of bacteria. Here we found that the Wsp signal transduction system regulated K1-T6SS expression via synthesizing the second messenger cyclic di-GMP (c-di-GMP), thus mediating antibacterial activity in P. putida. High-level c-di-GMP produced by Wsp system repressed the transcription of K1-T6SS genes in structural operon and vgrG1 operon. Transcriptional regulator FleQ and ATPase FleN functioned as repressors in the Wsp system-modulated K1-T6SS transcription. However, FleQ and FleN functioned as activators in biofilm formation, and Wsp system promoted biofilm formation largely in a FleQ/FleN-dependent manner. Furthermore, FleQ-FleN complex bound directly to the promoter of K1-T6SS structural operon in vitro, and c-di-GMP promoted the binding. Besides, P. putida biofilm cells showed higher c-di-GMP levels and lower antibacterial activity than planktonic cells. Overall, our findings reveal a mechanism by which Wsp system oppositely modulates antibacterial activity and biofilm formation via FleQ-FleN, and demonstrate the relationship between plankton/biofilm lifestyles and antibacterial activity in P. putida.}, } @article {pmid35175739, year = {2022}, author = {Wang, B and Liu, H and Sun, L and Jin, Y and Ding, X and Li, L and Ji, J and Chen, H}, title = {Correction to "Construction of High Drug Loading and Enzymatic Degradable Multilayer Films for Self-Defense Drug Release and Long-Term Biofilm Inhibition".}, journal = {Biomacromolecules}, volume = {23}, number = {3}, pages = {1473}, doi = {10.1021/acs.biomac.2c00123}, pmid = {35175739}, issn = {1526-4602}, } @article {pmid35172601, year = {2022}, author = {Piotrowski, M and Wultańska, D and Pituch, H}, title = {Effect of prebiotics on Bacteroides sp. adhesion and biofilm formation and synbiotic effect on Clostridioides difficile.}, journal = {Future microbiology}, volume = {17}, number = {}, pages = {363-375}, doi = {10.2217/fmb-2021-0206}, pmid = {35172601}, issn = {1746-0921}, mesh = {Bacteroides ; Biofilms ; Clostridioides ; *Clostridioides difficile ; Humans ; Prebiotics ; *Synbiotics ; }, abstract = {Aim: The objective of this study was to determine the effect of standard and candidate prebiotics on the adhesion and biofilm formation of Bacteroides sp. in monoculture and co-culture with Clostridioides difficile. Materials & methods: The effect of seven prebiotics on the adhesion and biofilm formation of Bacteroides sp. to three human cell lines was determined. The effect of Bacteroides sp. and fructooligosaccharides (FOS) on the adhesion and biofilm formation of C. difficile was tested by the co-incubation assay. Results: Inulin, mannose and raffinose presented the best anti-adhesion properties against Bacteroides sp. Combination of Bacteroides sp. with FOS decreased the adhesion of C. difficile. Conclusion: The study shows the potential role of prebiotics and synbiotics in decreasing the burden of C. difficile infections.}, } @article {pmid35172394, year = {2022}, author = {Suban, S and Sendersky, E and Golden, SS and Schwarz, R}, title = {Impairment of a cyanobacterial glycosyltransferase that modifies a pilin results in biofilm development.}, journal = {Environmental microbiology reports}, volume = {14}, number = {2}, pages = {218-229}, pmid = {35172394}, issn = {1758-2229}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Fimbriae Proteins/genetics ; Fimbriae, Bacterial/genetics ; *Glycosyltransferases/genetics ; Mutation ; }, abstract = {A biofilm inhibiting mechanism operates in the cyanobacterium Synechococcus elongatus. Here, we demonstrate that the glycosyltransferase homologue, Ogt, participates in the inhibitory process - inactivation of ogt results in robust biofilm formation. Furthermore, a mutational approach shows requirement of the glycosyltransferase activity for biofilm inhibition. This enzyme is necessary for glycosylation of the pilus subunit and for adequate pilus formation. In contrast to wild-type culture in which most cells exhibit several pili, only 25% of the mutant cells are piliated, half of which possess a single pilus. In spite of this poor piliation, natural DNA competence was similar to that of wild-type; therefore, we propose that the unglycosylated pili facilitate DNA transformation. Additionally, conditioned medium from wild-type culture, which contains a biofilm inhibiting substance(s), only partially blocks biofilm development by the ogt-mutant. Thus, we suggest that inactivation of ogt affects multiple processes including production or secretion of the inhibitor as well as the ability to sense or respond to it.}, } @article {pmid35171906, year = {2022}, author = {Sultan, AR and Tavakol, M and Lemmens-den Toom, NA and Croughs, PD and Verkaik, NJ and Verbon, A and van Wamel, WJB}, title = {Real time monitoring of Staphylococcus aureus biofilm sensitivity towards antibiotics with isothermal microcalorimetry.}, journal = {PloS one}, volume = {17}, number = {2}, pages = {e0260272}, pmid = {35171906}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Calorimetry/*methods ; Floxacillin/pharmacology ; Genetic Linkage ; Methicillin-Resistant Staphylococcus aureus/genetics/physiology ; Microbial Sensitivity Tests ; Rifampin/pharmacology ; Staphylococcus aureus/genetics/*physiology ; Vancomycin/pharmacology ; }, abstract = {Biofilm-associated infections with Staphylococcus aureus are difficult to treat even after administration of antibiotics that according to the standard susceptibility assays are effective. Currently, the assays used in the clinical laboratories to determine the sensitivity of S. aureus towards antibiotics are not representing the behaviour of biofilm-associated S. aureus, since these assays are performed on planktonic bacteria. In research settings, microcalorimetry has been used for antibiotic susceptibility studies. Therefore, in this study we investigated if we can use isothermal microcalorimetry to monitor the response of biofilm towards antibiotic treatment in real-time. We developed a reproducible method to generate biofilm in an isothermal microcalorimeter setup. Using this system, the sensitivity of 5 methicillin-sensitive S. aureus (MSSA) and 5 methicillin-resistant S. aureus (MRSA) strains from different genetic lineages were determined towards: flucloxacillin, cefuroxime, cefotaxime, gentamicin, rifampicin, vancomycin, levofloxacin, clindamycin, erythromycin, linezolid, fusidic acid, co-trimoxazole, and doxycycline. In contrast to conventional assays, our calorimetry-based biofilm susceptibility assay showed that S. aureus biofilms, regardless MSSA or MRSA, can survive the exposure to the maximum serum concentration of all tested antibiotics. The only treatment with a single antibiotic showing a significant reduction in biofilm survival was rifampicin, yet in 20% of the strains, emerging antibiotic resistance was observed. Furthermore, the combination of rifampicin with flucloxacillin, vancomycin or levofloxacin was able to prevent S. aureus biofilm from becoming resistant to rifampicin. Isothermal microcalorimetry allows real-time monitoring of the sensitivity of S. aureus biofilms towards antibiotics in a fast and reliable way.}, } @article {pmid35171575, year = {2022}, author = {Funari, R and Shen, AQ}, title = {Detection and Characterization of Bacterial Biofilms and Biofilm-Based Sensors.}, journal = {ACS sensors}, volume = {7}, number = {2}, pages = {347-357}, doi = {10.1021/acssensors.1c02722}, pmid = {35171575}, issn = {2379-3694}, mesh = {Anti-Bacterial Agents ; Bacteria ; *Biofilms ; *Biosensing Techniques ; }, abstract = {Microbial biofilms have caused serious concerns in healthcare, medical, and food industries because of their intrinsic resistance against conventional antibiotics and cleaning procedures and their capability to firmly adhere on surfaces for persistent contamination. These global issues strongly motivate researchers to develop novel methodologies to investigate the kinetics underlying biofilm formation, to understand the response of the biofilm with different chemical and physical treatments, and to identify biofilm-specific drugs with high-throughput screenings. Meanwhile microbial biofilms can also be utilized positively as sensing elements in cell-based sensors due to their strong adhesion on surfaces. In this perspective, we provide an overview on the connections between sensing and microbial biofilms, focusing on tools used to investigate biofilm properties, kinetics, and their response to chemicals or physical agents, and biofilm-based sensors, a type of biosensor using the bacterial biofilm as a biorecognition element to capture the presence of the target of interest by measuring the metabolic activity of the immobilized microbial cells. Finally we discuss possible new research directions for the development of robust and rapid biofilm related sensors with high temporal and spatial resolutions, pertinent to a wide range of applications.}, } @article {pmid35171340, year = {2022}, author = {Liu, L and Ji, Z and Zhao, K and Zhao, Y and Zhang, Y and Huang, S}, title = {Validation of housekeeping genes as internal controls for gene expression studies on biofilm formation in Bacillus velezensis.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {5-6}, pages = {2079-2089}, pmid = {35171340}, issn = {1432-0614}, support = {LY21C140001//Natural Science Foundation of Zhejiang Province/ ; 2022C02014//Technology Research Program of Zhejiang Province/ ; 2019C02018//Key Research and Development Program of Zhejiang Province/ ; }, mesh = {*Bacillus/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression ; Gene Expression Regulation, Bacterial ; *Genes, Essential ; }, abstract = {Bacillus velezensis is an important bacterium widely applied in agriculture and industry, and biofilms play critical roles in its environmental tolerance. The appropriate choice of reference genes is essential for key gene expression studies. Multiple internal control genes were selected and validated from the 21 housekeeping genes of B. velezensis by expression stability evaluation during biofilm formation and were used to study the expression of key genes involved in the process. The results showed that pyk, gyrA, recA, and gyrB were stably expressed, and the expression of pyk was the most stable during biofilm formation. A pair of two genes, pyk and gyrA, provided high-quality data when used as internal controls, and the combination of three genes, pyk, gyrA, and recA, was even better. The expression levels of pyk, gyrA, and recA approximated those of five key genes, abrB, epsD, kinC, sinR, and tasA, in biofilm formation, meeting the requirements of ideal internal control genes. The expression patterns of 5 key genes were studied with 16S, pyk, the pair of 2 genes, pyk and gyrA, and the combination of 3 genes, pyk, gyrA, and recA, as internal controls during the biofilm formation process. The results proved that pyk was a suitable internal control, as were the pair of 2 genes, pyk and gyrA, and the combination of 3 genes, pyk, gyrA, and recA. This study provided genes and gene combinations which were validated as suitable internal controls for gene expression studies, especially those on the mechanism of biofilm formation in B. velezensis or even other Bacillus spp. KEY POINTS: • Reference genes is necessary for gene expression study in biofilm formation of Bacillus velezensis • Pyk and 2 gene combinations were selected and validated from 21 common used genes • Expression of key genes in biofilm formation was normalized with the selected internal controls.}, } @article {pmid35169997, year = {2022}, author = {Heidari, R and Farajzadeh Sheikh, A and Hashemzadeh, M and Farshadzadeh, Z and Salmanzadeh, S and Saki, M}, title = {Antibiotic resistance, biofilm production ability and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa strains isolated from nosocomial infections in southwestern Iran.}, journal = {Molecular biology reports}, volume = {49}, number = {5}, pages = {3811-3822}, pmid = {35169997}, issn = {1573-4978}, support = {OG-9940//Ahvaz Jundishapur University of Medical Sciences/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Carbapenems/pharmacology ; Colistin/pharmacology ; *Cross Infection/epidemiology ; Drug Resistance, Microbial ; Genetic Variation ; Humans ; Iran/epidemiology ; Microbial Sensitivity Tests ; *Pseudomonas Infections/epidemiology ; Pseudomonas aeruginosa ; }, abstract = {BACKGROUND: This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains isolated from four types of nosocomial infections (NIs) including urinary tract infection (UTI), ventilator-associated pneumonia (VAP), surgical site infection (SSI), and bloodstream infection (BSI).

METHODS AND RESULTS: In total, 115 isolates of NIs-causing P. aeruginosa were collected from NIs. Antibiotic susceptibility testing (AST) was performed using disk diffusion method and minimum inhibitory concentrations. Biofilm formation was tested on 96-well polystyrene microtiter plates (MTP). CRPA isolates were genotyped using multiple-locus variable number of tandem repeat analysis (MLVA). The most resistance and susceptibility rates were observed to amikacin (70.6%) and colistin (96.1%), respectively. Colistin and meropenem were the most active antimicrobial agents in VAP, SSI, and BSI. While, colistin and cefepime were the most active in UTIs. In total, 52.2% (n = 60/115) of P. aeruginosa isolates were carbapenem resistant, of which 95.0%, 55.0%, and 5.0% were multidrug-resistant, extensively drug-resistant, and pandrug-resistant, respectively. There was a significant association between resistance to carbapenem and resistance to other antibiotics except for piperacillin/tazobactam. The biofilm production of CRPA isolates was 95.0%, of which 23.3% were strong biofilm producers. Based on MLVA, there were 34 different types of CRPA isolates classified into three main clusters and 5 sub clusters.

CONCLUSION: The association of CRPA with other antibiotic resistance, the high rates of biofilm production, and the high genetic diversity of the isolates may be a warning of the need for a careful surveillance program.}, } @article {pmid35167954, year = {2022}, author = {Luan, C and Jiang, N and Zhou, X and Zhang, C and Zhao, Y and Li, Z and Li, C}, title = {Antibacterial and anti-biofilm activities of probiotic Lactobacillus curvatus BSF206 and Pediococcus pentosaceus AC1-2 against Streptococcus mutans.}, journal = {Microbial pathogenesis}, volume = {164}, number = {}, pages = {105446}, doi = {10.1016/j.micpath.2022.105446}, pmid = {35167954}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Dental Caries/prevention & control ; Humans ; Lactobacillus/physiology ; Pediococcus pentosaceus ; *Probiotics/pharmacology ; Streptococcus mutans ; }, abstract = {Streptococcus mutans (S. mutans) is the most important oral pathogenic bacterial cause of dental caries. Here we investigated the abilities of probiotic lactobacillus strains of Lactobacillus curvatus (L. curvatus) BSF206 and Pediococcus pentosaceus (P. pentosaceus) AC1-2 to control S. mutans. Both probiotic strains are acid and bile salt tolerant and are resistant to hydrogen peroxide and lysozyme to promote their survival within the oral environment. In addition, both strains are highly hydrophobic and are also capable of engaging in electrostatic interactions. These properties enhance abilities of both strains to adhere to gingival epithelial cells and HT-29 for improved colonization of oral tissues, while also enabling these probiotics auto-aggregate and to form aggregates with S. mutans that both may prevent S. mutans from colonizing oral tissues and facilitate the clearance of the cariogenic bacteria from the mouth during swallowing of food and saliva. Furthermore, results presented herein revealed that L. curvatus BSF206 and P. pentosaceus AC1-2 effectively inhibited S. mutans activities (biofilm formation, secretion of extracellular matrix components, synthesis of water-insoluble glucans) and led to downregulation of expression of key S. mutans genes involved in biofilm production (gtfA, gtfB, ftf, brpA). Taken together, these results indicate that L. curvatus BSF206 and P. pentosaceus AC1-2 can inhibit S. mutans biofilm formation as a new strategy for preventing dental caries.}, } @article {pmid35166997, year = {2022}, author = {Gao, K and Zhang, B and Zhao, F}, title = {Antibiofilm Effect of Curcumin Against Staphylococcus aureus Surface Wound Biofilm-Associated Infection: In Vitro and In Silico.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35166997}, issn = {1559-0291}, abstract = {Biofilm is the consortia of the sessile group of microbial species that are adhered to the biotic and abiotic surfaces with the help of extracellular polymeric substances (EPS) and glycocalyx. A wound is a lesion on the epidermal surface that exposes the underlying tissues to the external environment and thus forms a region of proliferation for several species of Staphylococcus aureus. S. aureus is the most commonly observed nosocomial biofilm-forming organism that is responsible for the development of wound-associated infections. The biofilm prevents the penetration of the drug molecules thereby resulting in the development of antibiotic and multi-drug resistance among the organism. Thus, the use of alternative therapeutics has paved the path in the treatment of biofilm-associated infections. Curcumin has been used for the purpose of treating various illnesses from time immemorial. In this study, we observed that curcumin was able to bring about a reduction in the biofilm formed by S. aureus in the wound infection among the patients. The in silico studies revealed that curcumin possessed the ability to bring about interaction with the biofilm-forming proteins of S. aureus effectively.}, } @article {pmid35166712, year = {2022}, author = {Wagner, BM and Daigger, GT and Love, NG}, title = {Assessing membrane aerated biofilm reactor configurations in mainstream anammox applications.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {85}, number = {3}, pages = {943-960}, doi = {10.2166/wst.2022.013}, pmid = {35166712}, issn = {0273-1223}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Biofilms ; *Bioreactors ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater ; }, abstract = {Partial nitritation anammox (PNA) membrane aerated biofilm reactors (MABRs) have the potential to be employed in mainstream wastewater treatment and can drastically decrease the energy and carbon requirements for nitrogen removal. Previous PNA MABR studies have looked at 1-stage systems, but no study has holistically compared the performance of different MABR configurations. In this study, a PNA MABR was mechanistically modelled to determine the impact of the reactor configuration (1-stage, hybrid, or 2-stage system) on the location of the preferred niche for anammox bacteria and the overall nitrogen removal performance. Results from this study show that the 2-stage configuration, which used an MABR with a thin biofilm for nitritation and a moving bed biofilm reactor for anammox, had a 20% larger nitrogen removal rate than the 1-stage or hybrid configurations. This suggests that an MABR should focus on maximizing nitrite production with anammox implemented in a second-stage biofilm reactor to achieve the most cost-effective nitrogen removal. However, the optimal configuration will likely be facility specific, as each facility differs in operating costs, construction costs, footprint, and effluent limits. Additional experimentation is required to confirm these results, but this work narrows the number of viable configurations that need to be tested. The results of this study will inform researchers and engineers how to best implement PNA MABRs in mainstream nitrogen removal at larger scales.}, } @article {pmid35166016, year = {2022}, author = {Salisbury, AM and Mullin, M and Foulkes, L and Chen, R and Percival, SL}, title = {Controlled-release iodine foam dressings demonstrate broad-spectrum biofilm management in several in vitro models.}, journal = {International wound journal}, volume = {19}, number = {7}, pages = {1717-1728}, pmid = {35166016}, issn = {1742-481X}, mesh = {Humans ; Staphylococcus aureus ; *Wound Infection/drug therapy/microbiology ; Silver/therapeutic use ; *Iodine/therapeutic use ; Delayed-Action Preparations/therapeutic use ; Bandages ; Biofilms ; Pseudomonas aeruginosa ; *Staphylococcal Infections ; }, abstract = {Multiple in vitro models were utilised to evaluate the biofilm management capabilities of seven commercially-available wound dressings, varying in composition and antibacterial ingredients, to reduce common aerobic, anaerobic, and multispecies biofilms. The Center for Disease Control bioreactor was used to evaluate single species Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) 24 and 48 hours biofilms, as well as a multispecies biofilm consisting of these two organisms in addition to Enterococcus faecalis (E. faecalis). As wound biofilms often exist in hypoxic wound environments, a direct contact anaerobic model system was used to evaluate efficacy on Bacteroides fragilis (B. fragilis). Biofilm control was evaluated against P. aeruginosa in the drip flow bioreactor model, where a constant flow of proteinaceous media is used to create a more challenging and wound-like model. The results demonstrated that biofilm management capabilities varied amongst wound dressings. Two dressings, a controlled-release iodine foam dressing and a silver nanocrystalline dressing, showed potent >4 log reductions in recovered organisms compared with untreated controls in all biofilm models evaluated. The effectiveness of other dressings to manage bioburden varied between dressing, test organism, and model system. A silver foam dressing showed moderate biofilm control in some models. However, biofilm exposure to methylene blue and gentian violet-containing foam dressings showed negligible log reductions in all in vitro biofilm methods examined. The data outlined in this in vitro study support the use of the iodine foam dressing for wounds with infection and biofilm.}, } @article {pmid35165789, year = {2022}, author = {Kakoti, M and Dullah, S and Hazarika, DJ and Barooah, M and Boro, RC}, title = {Cinnabarinic acid from Trametes coccinea fruiting bodies exhibits antibacterial activity through inhibiting the biofilm formation.}, journal = {Archives of microbiology}, volume = {204}, number = {3}, pages = {173}, pmid = {35165789}, issn = {1432-072X}, support = {EEQ/2016/000631//Science and Engineering Research Board/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacillus cereus ; Biofilms ; Fruiting Bodies, Fungal ; Microbial Sensitivity Tests ; Oxazines ; *Plant Extracts ; Polyporaceae ; *Trametes ; }, abstract = {Wild mushrooms are rich sources of natural compounds with potent bioactive properties. Several important metabolites have been reported from mushrooms, which possess clinically important bioactive properties like antibacterial, anticancer, antidiabetic, and neuroprotective activity. In this study, we have evaluated the antimicrobial activity of Trametes coccinea fruiting body extracts against different bacterial isolates, viz., Bacillus subtilis, Bacillus cereus, and Escherichia coli. Fruiting bodies of three T. coccinea samples, of which two were collected from Santipur, Arunachal Pradesh and one collected from Jorhat, Assam, were used for extraction using methanol. The extracts showed significant antimicrobial activity against all the test bacteria. Minimum Inhibitory Concentration (MIC) of the extracts against Bacillus subtilis, Bacillus cereus, and Escherichia coli was recorded as 400 µg/ml, 400 µg/ml, and 300 µg/ml, respectively. Furthermore, the bioactive compounds of the extract were separated and detected using Thin Layer Chromatography (TLC). Presence of cinnabarinic acid (CBA)-a potent antimicrobial compound- was detected in TLC, which was further confirmed through High Performance Liquid Chromatography (HPLC) and Electrospray Ionization-Mass Spectrometry (ESI-MS). Cinnabarinic acid was able to inhibit the formation of biofilms in Bacillus subtilis and B. cereus, suggesting that the compound can be beneficial in the management of biofilm-based antimicrobial resistance.}, } @article {pmid35165270, year = {2022}, author = {Jeske, A and Arce-Rodriguez, A and Thöming, JG and Tomasch, J and Häussler, S}, title = {Evolution of biofilm-adapted gene expression profiles in lasR-deficient clinical Pseudomonas aeruginosa isolates.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {6}, pmid = {35165270}, issn = {2055-5008}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cross-Sectional Studies ; Humans ; *Pseudomonas aeruginosa/metabolism ; Trans-Activators/genetics/metabolism ; *Transcriptome ; }, abstract = {The overall success of a pathogenic microbe depends on its ability to efficiently adapt to challenging conditions in the human host. Long-term evolution experiments track and predict adaptive trajectories and have contributed significantly to our understanding of the driving forces of bacterial adaptation. In this study, we conducted a cross-sectional study instead of long-term longitudinal evolution experiments. We analyzed the transcriptional profiles as well as genomic sequence variations of a large number of clinical Pseudomonas aeruginosa isolates that have been recovered from different infected human sites. Convergent changes in gene expression patterns were found in different groups of clinical isolates. The majority of repeatedly observed expression patterns could be attributed to a defective lasR gene, which encodes the major quorum-sensing regulator LasR. Strikingly, the gene expression pattern of the lasR-defective strains appeared to reflect a transcriptional response that evolves in a direction consistent with growth within a biofilm. In a process of genetic assimilation, lasR-deficient P. aeruginosa isolates appear to constitutively express a biofilm-adapted transcriptional profile and no longer require a respective environmental trigger. Our results demonstrate that profiling the functional consequences of pathoadaptive mutations in clinical isolates reveals long-term evolutionary pathways and may explain the success of lasR mutants in the opportunistic pathogen P. aeruginosa in a clinical context.}, } @article {pmid35164021, year = {2022}, author = {Olar, R and Badea, M and Chifiriuc, MC}, title = {Metal Complexes-A Promising Approach to Target Biofilm Associated Infections.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {3}, pages = {}, pmid = {35164021}, issn = {1420-3049}, mesh = {Animals ; Anti-Infective Agents/chemistry/pharmacology/therapeutic use ; Biocompatible Materials ; Biofilms/*drug effects ; Coordination Complexes/chemistry/pharmacology/*therapeutic use ; Extracellular Polymeric Substance Matrix/drug effects/metabolism ; Humans ; Infections/*drug therapy ; Schiff Bases ; }, abstract = {Microbial biofilms are represented by sessile microbial communities with modified gene expression and phenotype, adhered to a surface and embedded in a matrix of self-produced extracellular polymeric substances (EPS). Microbial biofilms can develop on both prosthetic devices and tissues, generating chronic and persistent infections that cannot be eradicated with classical organic-based antimicrobials, because of their increased tolerance to antimicrobials and the host immune system. Several complexes based mostly on 3D ions have shown promising potential for fighting biofilm-associated infections, due to their large spectrum antimicrobial and anti-biofilm activity. The literature usually reports species containing Mn(II), Ni(II), Co(II), Cu(II) or Zn(II) and a large variety of multidentate ligands with chelating properties such as antibiotics, Schiff bases, biguanides, N-based macrocyclic and fused rings derivatives. This review presents the progress in the development of such species and their anti-biofilm activity, as well as the contribution of biomaterials science to incorporate these complexes in composite platforms for reducing the negative impact of medical biofilms.}, } @article {pmid35163933, year = {2022}, author = {Poh, WH and Rice, SA}, title = {Recent Developments in Nitric Oxide Donors and Delivery for Antimicrobial and Anti-Biofilm Applications.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {3}, pages = {}, pmid = {35163933}, issn = {1420-3049}, support = {MOE2019-T2-1-050//Ministry of Education/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/metabolism ; Biofilms/drug effects/*growth & development ; Nitric Oxide Donors/*pharmacology ; }, abstract = {The use of nitric oxide (NO) is emerging as a promising, novel approach for the treatment of antibiotic resistant bacteria and biofilm infections. Depending on the concentration, NO can induce biofilm dispersal, increase bacteria susceptibility to antibiotic treatment, and induce cell damage or cell death via the formation of reactive oxygen or reactive nitrogen species. The use of NO is, however, limited by its reactivity, which can affect NO delivery to its target site and result in off-target effects. To overcome these issues, and enable spatial or temporal control over NO release, various strategies for the design of NO-releasing materials, including the incorporation of photo-activable, charge-switchable, or bacteria-targeting groups, have been developed. Other strategies have focused on increased NO storage and delivery by encapsulation or conjugation of NO donors within a single polymeric framework. This review compiles recent developments in NO drugs and NO-releasing materials designed for applications in antimicrobial or anti-biofilm treatment and discusses limitations and variability in biological responses in response to the use of NO for bacterial eradiation.}, } @article {pmid35163165, year = {2022}, author = {Guo, H and Tong, Y and Cheng, J and Abbas, Z and Li, Z and Wang, J and Zhou, Y and Si, D and Zhang, R}, title = {Biofilm and Small Colony Variants-An Update on Staphylococcus aureus Strategies toward Drug Resistance.}, journal = {International journal of molecular sciences}, volume = {23}, number = {3}, pages = {}, pmid = {35163165}, issn = {1422-0067}, support = {NSFC, 31572442//National Natural Science Foundation of China/ ; 2018YFD0500600//National Key Research and Development Program of China/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial/*genetics ; Gene Expression Regulation, Bacterial ; Humans ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/drug effects/*genetics/pathogenicity ; }, abstract = {Recently, the drawbacks arising from the overuse of antibiotics have drawn growing public attention. Among them, drug-resistance (DR) and even multidrug-resistance (MDR) pose significant challenges in clinical practice. As a representative of a DR or MDR pathogen, Staphylococcus aureus can cause diversity of infections related to different organs, and can survive or adapt to the diverse hostile environments by switching into other phenotypes, including biofilm and small colony variants (SCVs), with altered physiologic or metabolic characteristics. In this review, we briefly describe the development of the DR/MDR as well as the classical mechanisms (accumulation of the resistant genes). Moreover, we use multidimensional scaling analysis to evaluate the MDR relevant hotspots in the recent published reports. Furthermore, we mainly focus on the possible non-classical resistance mechanisms triggered by the two important alternative phenotypes of the S. aureus, biofilm and SCVs, which are fundamentally caused by the different global regulation of the S. aureus population, such as the main quorum-sensing (QS) and agr system and its coordinated regulated factors, such as the SarA family proteins and the alternative sigma factor σB (SigB). Both the biofilm and the SCVs are able to escape from the host immune response, and resist the therapeutic effects of antibiotics through the physical or the biological barriers, and become less sensitive to some antibiotics by the dormant state with the limited metabolisms.}, } @article {pmid35162866, year = {2022}, author = {Janka, E and Pathak, S and Rasti, A and Gyawali, S and Wang, S}, title = {Simultaneous Heterotrophic Nitrification and Aerobic Denitrification of Water after Sludge Dewatering in Two Sequential Moving Bed Biofilm Reactors (MBBR).}, journal = {International journal of environmental research and public health}, volume = {19}, number = {3}, pages = {}, pmid = {35162866}, issn = {1660-4601}, mesh = {Biofilms ; Bioreactors/microbiology ; Denitrification ; Humans ; *Nitrification ; Nitrogen/analysis ; *Sewage ; Waste Disposal, Fluid/methods ; Wastewater ; Water ; }, abstract = {Water after sludge dewatering, also known as reject water from anaerobic digestion, is recycled back to the main wastewater treatment inlet in the wastewater treatment plant Porsgrunn, Norway, causing periodic process disturbance due to high ammonium of 568 (±76.7) mg/L and total chemical oxygen demand (tCOD) of 2825 (±526) mg/L. The main aim of this study was the simultaneous treatment of reject water ammonium and COD using two pilot-scale sequential moving bed biofilm reactors (MBBR) implemented in the main wastewater treatment stream. The two pilot MBBRs each had a working volume of 67.4 L. The biofilm carriers used had a protected surface area of 650 m[2]/m[3] with a 60% filling ratio. The results indicate that the combined ammonia removal efficiency (ARE) in both reactors was 65.9%, while the nitrite accumulation rate (NAR) and nitrate production rate (NPR) were 80.2 and 19.8%, respectively. Over 28% of the reject water's tCOD was removed in both reactors. The heterotrophic nitrification and oxygen tolerant aerobic denitrification were the key biological mechanisms found for the ammonium removal in both reactors. The dominant bacterial family in both reactors was Alcaligenaceae, capable of simultaneous heterotrophic nitrification and denitrification. Moreover, microbial families that were found with equal potential for application of simultaneous heterotrophic nitrification and aerobic denitrification including Cloacamonaceae, Alcaligenaceae, Comamonadaceae, Microbacteriaceae, and Anaerolinaceae.}, } @article {pmid35160348, year = {2022}, author = {Bueno, J and Virto, L and Toledano-Osorio, M and Figuero, E and Toledano, M and Medina-Castillo, AL and Osorio, R and Sanz, M and Herrera, D}, title = {Antibacterial Effect of Functionalized Polymeric Nanoparticles on Titanium Surfaces Using an In Vitro Subgingival Biofilm Model.}, journal = {Polymers}, volume = {14}, number = {3}, pages = {}, pmid = {35160348}, issn = {2073-4360}, abstract = {This investigation aimed to evaluate the antibacterial effect of polymeric nanoparticles (NPs), functionalized with calcium, zinc, or doxycycline, using a subgingival biofilm model of six bacterial species (Streptococcus oralis,Actinomyces naeslundii, Veillonela parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans) on sandblasted, large grit, acid-etched titanium discs (TiDs). Undoped NPs (Un-NPs) or doped NPs with calcium (Ca-NPs), zinc (Zn-NPs), or doxycycline (Dox-NPs) were applied onto the TiD surfaces. Uncovered TiDs were used as negative controls. Discs were incubated under anaerobic conditions for 12, 24, 48, and 72 h. The obtained biofilm structure was studied by scanning electron microscopy (SEM) and its vitality and thickness by confocal laser scanning microscopy (CLSM). Quantitative polymerase chain reaction of samples was used to evaluate the bacterial load. Data were evaluated by analysis of variance (p < 0.05) and post hoc comparisons with Bonferroni adjustments (p < 0.01). As compared with uncovered TiDs, Dox-NPs induced higher biofilm mortality (47.21% and 85.87%, respectively) and reduced the bacterial load of the tested species, after 72 h. With SEM, scarce biofilm formation was observed in Dox-NPs TiDs. In summary, Dox-NPs on TiD reduced biofilm vitality, bacterial load, and altered biofilm formation dynamics.}, } @article {pmid35160347, year = {2022}, author = {Ratka, C and Weigl, P and Henrich, D and Koch, F and Schlee, M and Zipprich, H}, title = {Correction: Ratka et al. The Effect of In Vitro Electrolytic Cleaning on Biofilm-Contaminated Implant Surfaces. J. Clin. Med. 2019, 8, 1397.}, journal = {Journal of clinical medicine}, volume = {11}, number = {3}, pages = {}, pmid = {35160347}, issn = {2077-0383}, abstract = {There was an error in the original article [...].}, } @article {pmid35160174, year = {2022}, author = {Pauter, K and Railean-Plugaru, V and Złoch, M and Pomastowski, P and Szultka-Młyńska, M and Buszewski, B}, title = {Identification, Structure and Characterization of Bacillus tequilensis Biofilm with the Use of Electrophoresis and Complementary Approaches.}, journal = {Journal of clinical medicine}, volume = {11}, number = {3}, pages = {}, pmid = {35160174}, issn = {2077-0383}, support = {2020/37/B/ST4/02136//National Science Center/ ; }, abstract = {Biofilm is a complex structure formed as a result of the accumulation of bacterial cell clusters on a surface, surrounded by extracellular polysaccharide substances (EPSs). Biofilm-related bacterial infections are a significant challenge for clinical treatment. Therefore, the main goal of our study was to design a complementary approach in biofilm characterization before and after the antibiotic treatment. The 16S rRNA gene sequencing allowed for the identification of Bacillus tequilensis, as a microbial model of the biofilm formation. Capillary electrophoresis demonstrates the capability to characterize and show the differences of the electrophoretic mobility between biofilms untreated and treated with antibiotics: amoxicillin, gentamicin and metronidazole. Electrophoretic results show the clumping phenomenon (amoxicillin and gentamicin) as a result of a significant change on the surface electric charge of the cells. The stability of the dispersion study, the molecular profile analysis, the viability of bacterial cells and the scanning morphology imaging were also investigated. The microscopic and spectrometry study pointed out the degradation/remodeling of the EPSs matrix, the inhibition of the cell wall synthesis and blocking the ribosomal protein synthesis by amoxicillin and gentamicin. However, untreated and treated bacterial cells show a high stability for the biofilm formation system. Moreover, on the basis of the type of the antibiotic treatment, the mechanism of used antibiotics in cell clumping and degradation were proposed.}, } @article {pmid35157876, year = {2022}, author = {Yang, W and Ali, A and Su, J and Liu, J and Wang, Z and Zhang, L}, title = {Microbial induced calcium precipitation based anaerobic immobilized biofilm reactor for fluoride, calcium, and nitrate removal from groundwater.}, journal = {Chemosphere}, volume = {295}, number = {}, pages = {133955}, doi = {10.1016/j.chemosphere.2022.133955}, pmid = {35157876}, issn = {1879-1298}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Calcium ; Calcium Fluoride ; *Cupriavidus ; Denitrification ; Fluorides ; *Groundwater ; Nitrates ; }, abstract = {In this study, the anaerobic quartz sand fixed biofilm reactor containing Cupriavidus sp. W12 was established to simultaneously remove calcium (Ca[2+]), fluoride (F[-]) and nitrate (NO3[-]N) from groundwater. After 84 days of continuous operation, the optimum operating parameters and defluoridation mechanism were explored, and the microbial community structure under different pH environments were compared and analyzed. Under the optimal operation conditions (HRT of 6 h, initial Ca[2+] concentration of 180 mg L[-1], and pH of 7.0), the removal efficiencies of Ca[2+], F[-], and NO3[-]N were 58.97%, 91.93%, and 100%, respectively. Gas chromatography (GC) results indicate that N2 is the main gas produced by the bioreactor. Three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) showed that extracellular polymers (EPS) are produced during bacterial growth and metabolism. The results of Scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR) demonstrated that the defluoridation mechanism is attributed to the synergetic effects of ion exchange, co-precipitation, and chemisorption. The comparative analysis of the microbial community structure under different pH conditions show that Cupriavidus is the dominant bacteria in the bioreactor throughout the experiment, and it shows a prominent advantage at pH of 7.0. This research provides an application foundation for anaerobic microbial induced calcium precipitation (MICP) bioremediation of Ca[2+], F[-], and NO3[-]N from groundwater.}, } @article {pmid35155655, year = {2021}, author = {Zhou, Y and Yu, F and Chen, M and Zhang, Y and Qu, Q and Wei, Y and Xie, C and Wu, T and Liu, Y and Zhang, Z and Chen, X and Dong, C and Che, R and Li, Y}, title = {Tylosin Inhibits Streptococcus suis Biofilm Formation by Interacting With the O-acetylserine (thiol)-lyase B CysM.}, journal = {Frontiers in veterinary science}, volume = {8}, number = {}, pages = {829899}, pmid = {35155655}, issn = {2297-1769}, abstract = {Streptococcus suis (S. suis) can decrease its virulence or modify local conditions through biofilm formation, which promotes infection persistence in vivo. Biofilm formation is an important cause of chronic drug-resistant S. suis infection. The aim of this study was to evaluate whether tylosin effectively inhibits S. suis biofilm formation by interacting with O-acetylserine (thiol)-lyase B (CysM), a key enzymatic regulator of cysteine synthesis. Biofilm formation of the mutant (ΔcysM) strain was significantly lower compared to the wild-type ATCC 700794 strain. Tylosin inhibited cysM gene expression, decreased extracellular matrix contents, and reduced cysteine, homocysteine, and S-adenosylmethionine levels, indicating its potential value as an effective inhibitor of S. suis biofilm formation. Furthermore, using biolayer interferometry technology and fourier-transform infrared spectroscopy, we found that tylosin and CysM could be combined directly. Overall, these results provide evidence that tylosin inhibits S. suis biofilm formation by interacting with CysM.}, } @article {pmid35155575, year = {2022}, author = {Corrêa-Almeida, C and Borba-Santos, LP and Rollin-Pinheiro, R and Barreto-Bergter, E and Rozental, S and Kurtenbach, E}, title = {Characterization of Aspergillus nidulans Biofilm Formation and Structure and Their Inhibition by Pea Defensin Psd2.}, journal = {Frontiers in molecular biosciences}, volume = {9}, number = {}, pages = {795255}, pmid = {35155575}, issn = {2296-889X}, abstract = {Approximately four million people contract fungal infections every year in Brazil, primarily caused by Aspergillus spp. The ability of these fungi to form biofilms in tissues and medical devices complicates treatment and contributes to high rates of morbidity and mortality in immunocompromised patients. Psd2 is a pea defensin of 5.4 kDa that possesses good antifungal activity against planktonic cells of representative pathogenic fungi. Its function depends on interactions with membrane and cell wall lipid components such as glucosylceramide and ergosterol. In the present study, we characterized Aspergillus nidulans biofilm formation and determined the effect of Psd2 on A. nidulans biofilms. After 4 hours, A. nidulans conidia adhered to polystyrene surfaces and formed a robust extracellular matrix-producing biofilm at 24 h, increasing thickness until 48 h Psd2 inhibited A. nidulans biofilm formation in a dose-dependent manner. Most notably, at 10 μM Psd2 inhibited 50% of biofilm viability and biomass and 40% of extracellular matrix production. Psd2 significantly decreased the colonized surface area by the biofilm and changed its level of organization, causing a shortening of length and diameter of hyphae and inhibition of conidiophore formation. This activity against A. nidulans biofilm suggests a potential use of Psd2 as a prototype to design new antifungal agents to prevent biofilm formation by A. nidulans and related species.}, } @article {pmid35155271, year = {2021}, author = {Bronnec, V and Eilers, H and Jahns, AC and Omer, H and Alexeyev, OA}, title = {Propionibacterium (Cutibacterium) granulosum Extracellular DNase BmdE Targeting Propionibacterium (Cutibacterium) acnes Biofilm Matrix, a Novel Inter-Species Competition Mechanism.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {809792}, pmid = {35155271}, issn = {2235-2988}, mesh = {*Acne Vulgaris/microbiology ; *Biofilms ; *Deoxyribonucleases ; Extracellular Polymeric Substance Matrix ; Humans ; *Propionibacterium acnes/enzymology ; }, abstract = {Acne vulgaris is the most common dermatological disorder worldwide affecting more than 80% of adolescents and young adults with a global prevalence of 231 million cases in 2019. The involvement of the skin microbiome disbalance in the pathophysiology of acne is recognized, especially regarding the relative abundance and diversity of Propionibacterium acnes a well-known dominant human skin commensal. Biofilms, where bacteria are embedded into a protective polymeric extracellular matrix, are the most prevalent life style for microorganisms. P. acnes and its biofilm-forming ability is believed to be a contributing factor in the development of acne vulgaris, the persistence of the opportunistic pathogen and antibiotic therapy failures. Degradation of the extracellular matrix is one of the strategies used by bacteria to disperse the biofilm of competitors. In this study, we report the identification of an endogenous extracellular nuclease, BmdE, secreted by Propionibacterium granulosum able to degrade P. acnes biofilm both in vivo and in vitro. This, to our knowledge, may represent a novel competitive mechanism between two closely related species in the skin. Antibiotics targeting P. acnes have been the mainstay in acne treatment. Extensive and long-term use of antibiotics has led to the selection and spread of resistant bacteria. The extracellular DNase BmdE may represent a new bio-therapeutical strategy to combat P. acnes biofilm in acne vulgaris.}, } @article {pmid35153795, year = {2022}, author = {Kang, X and Ma, Q and Wang, G and Li, N and Mao, Y and Wang, X and Wang, Y and Wang, G}, title = {Potential Mechanisms of Quercetin Influence the ClfB Protein During Biofilm Formation of Staphylococcus aureus.}, journal = {Frontiers in pharmacology}, volume = {13}, number = {}, pages = {825489}, pmid = {35153795}, issn = {1663-9812}, abstract = {This study aimed to establish the mode of binding between Quercetin (QEN) and an essential protein called ClfB in forming biofilm in Staphylococcus aureus (S. aureus). In this study, the raw data of GSE163153 were analyzed for quality control, alignment, and gene counts, and the differential analysis detected the key differentially expressed genes (DEGs) assisting in the formation of the S. aureus biofilm. Then, the protein-protein interaction (PPI) and gene function enrichment analyses of the target genes, identified a gene called clfB to be closely related to biofilm formation. ClfB was structurally characterized, molecularly docked, and kinetically simulated to unravel the mode of binding of QEN to ClfB. Meanwhile, the growth curve and transmission electron microscopy methods examined the effect of QEN on the S. aureus growth. Results indicated that the clfB gene was increasingly expressed during biofilm formation and was involved in cell adhesion, pathogenicity, and infection. We identified 5 amino acid sites of ClfB (D272, R331, I379, K391, E490) as potential sites for binding QEN, which would indirectly influence the changes in the functional sites N234, D270, Y273, F328, inhibiting the formation of biofilm. Meanwhile, 128 μg/ml of QEN could significantly inhibit the S. aureus biofilm formation. This manuscript serves as a molecular foundation for QEN as an antibacterial drug providing a new perspective for developing antibacterial drugs.}, } @article {pmid35153244, year = {2022}, author = {Liaqat, I and Gulab, B and Hanif, U and Sultan, A and Sadiqa, A and Zafar, U and Afzaal, M and Naseem, S and Akram, S and Saleem, G}, title = {Honey Potential as Antibiofilm, Antiquorum Sensing and Dispersal Agent against Multispecies Bacterial Biofilm.}, journal = {Journal of oleo science}, volume = {71}, number = {3}, pages = {425-434}, doi = {10.5650/jos.ess21199}, pmid = {35153244}, issn = {1347-3352}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria ; Biofilms ; *Escherichia coli ; Humans ; Pseudomonas aeruginosa ; Quorum Sensing ; *Staphylococcus aureus ; }, abstract = {This study is first to test Pakistani honey bees, Apis dorsata and A. cerana honey samples as anti biofilm, anti quorum sensing (QS) and biofilm dispersal agents honey against multispecies biofilm of bacteria (obtained from obese patients). Briefly, five previously identified isolates Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Morganella morganii and Klebsiella pneumoniae (MT448672-MT448676) were selected. Antibiogram study of all five isolates was tested against three antibiotics viz., erythromycin (20 µg/mL), lincomycin (100 µg/mL) and rifampicin (100 µg/mL). In order to form multispecies biofilm, identified bacteria were grown in batch culture by mixing equal volumes (OD590nm = 0.1) of 2, 3 and 5 bacterial isolates. In total 11 groups (g1-g11) were made. Crystal violet (CV) staining method was used to evaluate the antibiofilm potential and biofilm dispersal potential of both honey samples. QS inhibition in P. aeruginosa was measured following culture supernatant method. Antibiogram study showed significant (p < 0.05) resistance by P. aeruginosa against tested antibiotics. E. coli, M. morganii and K. pneumoniae were significantly susceptible to erythromycin and S. aureus to lincomycin. Both honey samples at 2% and 5% concentrations showed significant (p < 0.05) inhibition potential of multispecies biofilm by all test groups (g1-g11). Though A. dorsata honey significantly inhibited biofilm formation at 2 and 5% against all groups but 2% concentration was highly significant against g2-g4 groups. Regarding A. cerana honey, 2% concentration was significantly effective against g1, g4-g7 and g9-g11 groups. Both honey samples significantly inhibited QS at 2 and 5%. The 5% concentration of A. dorsata honey significantly dispersed biofilm by all groups compared to 2% which showed dispersal potential only by g2 and g3 groups. Accordingly, honey samples showed significant antibiofilm, anti-QS and biofilm dispersal potentials thus can be considered as good alternative to antibiotics.}, } @article {pmid35152462, year = {2022}, author = {Sharifi, A and Nayeri Fasaei, B}, title = {Selected plant essential oils inhibit biofilm formation and luxS- and pfs-mediated quorum sensing by Escherichia coli O157:H7.}, journal = {Letters in applied microbiology}, volume = {74}, number = {6}, pages = {916-923}, doi = {10.1111/lam.13673}, pmid = {35152462}, issn = {1472-765X}, support = {//University of Tehran/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; *Escherichia coli O157/genetics ; *Oils, Volatile/chemistry/pharmacology ; Plant Extracts/pharmacology ; Quorum Sensing ; }, abstract = {Enterohemorrhagic Escherichia coli O157:H7 (EHEC) causes food-borne outbreaks worldwide and the bacteria form antimicrobial-tolerant biofilm. We investigated the abilities of Thymus daenensis and Satureja hortensis essential oils (EOs) to inhibit bacterial growth, biofilm formation and quorum sensing (QS) by E. coli O157:H7. The tested EOs were isolated from plant material by hydrodistillation and analysed under chromatography-mass spectrometry. The antibacterial and anti-biofilm activities of the EOs were determined by microdilution broth and microtitre-plate (MtP) tests, respectively. The QS inhibitory (QSI) potential was examined by inhibition of swimming and swarming motility at sub-MIC levels. Real-time quantitative reverse transcription PCR (RT-qPCR) was used to determine the expression of QS-system-related genes. The MICs for T. daenensis and S. hortensis EOs against EHEC were 3·12 and 6·25 μg ml[-1] , respectively and the MBCs were 6·25 and 12·5 μg ml[-1] , respectively. The MtP test showed a significant (P < 0·05) inhibitory and disruptive effect on both EOs for EHEC biofilm formation at MIC/2 (1·56 μg ml[-1] for T. daenensis; 3·12 μg ml[-1] for S. hortensis) and MIC/4 (0·78 μg ml[-1] for T. daenensis; 1·56 μg ml[-1] for S. hortensis) concentrations. Gene expression analysis revealed significant down-regulation of luxS and pfs following treatment with MIC/2 concentrations. The results of the present research point to the promising antibacterial, anti-biofilm and anti-QS potential of T. daenensis and S. hortensis EOs against E. coli O157:H7.}, } @article {pmid35152445, year = {2022}, author = {Ordinola-Zapata, R and Mansour, D and Saavedra, F and Staley, C and Chen, R and Fok, AS}, title = {In vitro efficacy of a non-instrumentation technique to remove intracanal multispecies biofilm.}, journal = {International endodontic journal}, volume = {55}, number = {5}, pages = {495-504}, pmid = {35152445}, issn = {1365-2591}, support = {UL1 TR002494/TR/NCATS NIH HHS/United States ; UL1-TR002494//NIH-National Center for Advancing Translational Sciences/ ; }, mesh = {Biofilms ; *Dental Plaque ; Dental Pulp Cavity ; Humans ; RNA, Ribosomal, 16S ; *Root Canal Irrigants ; Root Canal Preparation ; }, abstract = {AIM: The aim of this study was to assess the efficacy of a non-instrumentation technique to disinfect root canals infected by a human dental plaque-derived multispecies biofilm.

METHODOLOGY: Twenty-two mandibular incisors were accessed, autoclaved and inoculated with dental plaque. The Center for Disease Control biofilm reactor was used to promote contamination of the root canal space. In the conventional technique (control), the specimens were instrumented until size 35/04 and irrigated with 6% NaOCl. In the non-instrumentation technique, a glide path was established using K-files size 10-20 and specimens were immediately cleaned with the GentleWave System. Samples were obtained for culture and 16S rRNA gene sequencing. Differences in abundances of genera were evaluated using Kruskal-Wallis test, and differences in alpha diversity were compared using anova. Alpha and beta diversity indices were calculated using mothur. The Shannon and Chao1 indices were used to measure alpha diversity. The Bray-Curtis dissimilarity was used to measure beta diversity. Differences in community composition were evaluated using analysis of similarity with Bonferroni correction for multiple comparisons.

RESULTS: The total numbers of reads in biological samples ranged from 126 to 45 286. Significantly fewer reads were obtained from samples following cleaning by either method (p < .0001), and significantly fewer reads were obtained in post-cleaning samples following conventional versus non-instrumentation cleaning regiment (p = .002). Communities in pre-treatment samples were similar in both groups; however, significantly greater relative abundances of Streptococcus, Veillonella and Campylobacter were observed following cleaning using non-instrumentation technique (Kruskal-Wallis p = .009, .033, and .001, respectively). Whilst no significant differences were observed in Shannon alpha diversity, the Chao1 index was significantly lower in post-cleaning samples.

CONCLUSIONS: Significant shifts in composition were observed following cleaning by using both regimens, but the impact of this change was greater following a conventional cleaning technique.}, } @article {pmid35151101, year = {2022}, author = {Iafisco, M and Carella, F and Degli Esposti, L and Adamiano, A and Catalucci, D and Modica, J and Bragonzi, A and Vitali, A and Torelli, R and Sanguinetti, M and Bugli, F}, title = {Biocompatible antimicrobial colistin loaded calcium phosphate nanoparticles for the counteraction of biofilm formation in cystic fibrosis related infections.}, journal = {Journal of inorganic biochemistry}, volume = {230}, number = {}, pages = {111751}, doi = {10.1016/j.jinorgbio.2022.111751}, pmid = {35151101}, issn = {1873-3344}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Calcium Phosphates/pharmacology ; Colistin/pharmacology/therapeutic use ; *Cystic Fibrosis/drug therapy ; Humans ; *Nanoparticles ; Pseudomonas aeruginosa ; }, abstract = {The use of inhalable nanoparticles (NPs) for cystic fibrosis (CF) has been advocated as a promising tool to improve the efficacy of antimicrobials taking advantage of their ability to penetrate airway mucus and pathogen biofilm and to release the drug in or in proximity to the enclosed bacteria. Here, inhalable calcium phosphate (CaP) NPs were functionalized with colistin (Col) which is one of the most active antimicrobials against Gram-negative bacteria. The adsorption kinetic and isotherm of Col on CaP-NPs were investigated and fitted according to different mathematical models and revealed an electrostatic interaction between positively charged amine groups of Col and negatively charged surface of CaP-NPs. The maximum Col payload was of about 50 mg g[-1] of CaP-NPs. After functionalization, despite an increase of size (213 vs 95 nm), in citrate solution, CaP-NPs maintained a dimension and surface charge considered suitable for crossing mucus barrier. CaP-NPs do not interact with mucin and are able to permeate a layer of artificial mucus. In vitro tests on pulmonary cells demonstrated that CaP-NPs are not cytotoxic up to a concentration of 125 μg mL[-1]. The antimicrobial and antibiofilm activity of Col loaded CaP-NPs tested on Pseudomonas aeruginosa RP73, a clinical strain isolated from a CF patient, was similar to that of free Col demonstrating that the therapeutic effect of Col adsorbed on CaP-NPs was retained. This work represents the first attempt to use CaP-NPs as delivery system for the CF treatment. The encouraging results open the way to further studies.}, } @article {pmid35150713, year = {2022}, author = {Sun, Q and Zhu, G}, title = {Simultaneous denitrification and antibiotic degradation of low-C/N-ratio wastewater by a three-dimensional biofilm-electrode reactor: Performance and microbial response.}, journal = {Environmental research}, volume = {210}, number = {}, pages = {112856}, doi = {10.1016/j.envres.2022.112856}, pmid = {35150713}, issn = {1096-0953}, mesh = {Anti-Bacterial Agents ; Biofilms ; Bioreactors ; *Denitrification ; Electrodes ; Nitrates/analysis ; Nitrogen/analysis ; *Wastewater/chemistry ; }, abstract = {Three-dimensional biofilm-electrode reactors (3D-BERs) were fabricated and used to simultaneously remove nitrate and metronidazole (MNZ) from low-C/N-ratio wastewater. The results showed that 1 mg/L MNZ significantly promoted nitrate removal. After MNZ was added to the reactor, the removal efficiencies of total nitrogen (TN) and NO3[-]-N increased significantly from 18.97% and 52.09% to 71.63% and 99.98% within 6 h, respectively. The MNZ-removal kinetics conformed to a pseudo-first-order model, and the removal rate constant reached a maximum value of 0.853 h[-1], which was 4.1 and 2.8 times higher than that of pure microorganisms and pure electrochemical reactors, respectively. This indicated that the 3D-BERs constructed in this study were capable of simultaneous MNZ degradation and denitrification. In the presence of nitrate, six MNZ-degradation intermediates were identified, and four MNZ transformation pathways were proposed, including cleavage of hydroxyethyl groups, reduction of nitro groups, N-denitration, and deprotonation of side-chain hydroxyl groups. High-throughput sequencing revealed that the reactor was rich in various MNZ-degraders and denitrifiers, such as Hydrogenophaga, Methylomonas, Crenohrix, Dechloromonas, and Methylophilus. A function prediction analysis of nitrogen metabolism showed that the 3D-BER reactor with MNZ had higher denitrification activity than the other reactors tested. It was speculated that the intermediates produced by MNZ could act as carbon sources allowing denitrifying bacteria to perform denitrification, which made a nonnegligible contribution to the removal of nitrogen.}, } @article {pmid35150429, year = {2022}, author = {He, S and Song, N and Yao, Z and Jiang, H}, title = {An assessment of the purification performance and resilience of sponge-based aerobic biofilm reactors for treating polluted urban surface waters.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {30}, pages = {45919-45932}, pmid = {35150429}, issn = {1614-7499}, support = {2017ZX07204005//China National Critical Project for Science and Technology on Water Pollution Prevention and Control/ ; }, mesh = {Biofilms ; Bioreactors ; *Nitrogen/analysis ; *Nitrogen Dioxide ; Water Pollution ; }, abstract = {Pollutants are continuously released into surface waters, which decrease the dissolved oxygen (DO) concentration and leads to the formation of black-odorous water, especially in slow-flowing urban lakes and enclosed small ponds. In situ treatment by artificial aeration or water cycling, coupled with biofilm, can address this problem without occupying large amounts of land. In this study, we designed a novel sponge-based aerobic biofilm reactor (SABR) and evaluated its performance in purifying urban surface water under different conditions. In the urban lake water treatment, the continuous inflow results revealed that the NH4[+]-N and NO2[-]-N concentrations in the effluent were stable and remained lower than 0.10 mg/L and 0.05 mg/L, respectively. Abrupt increases in the NH4[+]-N and NO2[-]-N concentrations in the influent and sudden increases in the NH4[+]-N and NO2[-]-N concentrations in the effluent were observed, and only 4 to 8 days were required for the concentrations to decline below 0.10 mg/L and 0.05 mg/L, respectively. Increases in the polyurethane sponge filling ratios in the SABRs can reduce the DO concentration but do not affect NH4[+]-N removal. When no biodegradable organic matter was present in the enclosed surface water, the degradation time of NH4[+]-N from 14.22 to 0.10 mg/L was only 9 days when SABRs were combined with water cycling, which was shorter than the time needed by water cycling alone (16 days), and most of the NH4[+]-N was converted to NO3[-]-N. When massive amounts of biodegradable organic matter were present in the enclosed surface water, 22 days were required to remove the NH4[+]-N when SABRs were combined with water cycling. Our results indicated that organic matter could be used as a carbon source to eliminate the produced NO3[-]-N in SABRs. Therefore, the newly developed bioreactor provides an effective approach for treating N-polluted urban surface waters.}, } @article {pmid35148684, year = {2022}, author = {Padgett-Pagliai, KA and Pagliai, FA and da Silva, DR and Gardner, CL and Lorca, GL and Gonzalez, CF}, title = {Osmotic stress induces long-term biofilm survival in Liberibacter crescens.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {52}, pmid = {35148684}, issn = {1471-2180}, mesh = {Biofilms/*growth & development ; Citrus/*microbiology ; Liberibacter/pathogenicity/physiology ; *Microbial Viability ; *Osmotic Pressure ; Plant Diseases/*microbiology ; Time Factors ; }, abstract = {Citrus greening, also known as Huanglongbing (HLB), is a devastating citrus plant disease caused predominantly by Liberibacter asiaticus. While nearly all Liberibacter species remain uncultured, here we used the culturable L. crescens BT-1 as a model to examine physiological changes in response to the variable osmotic conditions and nutrient availability encountered within the citrus host. Similarly, physiological responses to changes in growth temperature and dimethyl sulfoxide concentrations were also examined, due to their use in many of the currently employed therapies to control the spread of HLB. Sublethal heat stress was found to induce the expression of genes related to tryptophan biosynthesis, while repressing the expression of ribosomal proteins. Osmotic stress induces expression of transcriptional regulators involved in expression of extracellular structures, while repressing the biosynthesis of fatty acids and aromatic amino acids. The effects of osmotic stress were further evaluated by quantifying biofilm formation of L. crescens in presence of increasing sucrose concentrations at different stages of biofilm formation, where sucrose-induced osmotic stress delayed initial cell attachment while enhancing long-term biofilm viability. Our findings revealed that exposure to osmotic stress is a significant contributing factor to the long term survival of L. crescens and, possibly, to the pathogenicity of other Liberibacter species.}, } @article {pmid35148641, year = {2022}, author = {Davis, SC and Li, J and Gil, J and Valdes, J and Solis, M and Higa, A}, title = {A novel dressing with silver to treat meticillin-resistant Staphylococcus aureus biofilm infection in a pig model.}, journal = {Journal of wound care}, volume = {31}, number = {Sup2}, pages = {S42-S48}, doi = {10.12968/jowc.2022.31.Sup2.S42}, pmid = {35148641}, issn = {0969-0700}, mesh = {Animals ; Bandages ; Biofilms ; Methicillin ; *Methicillin-Resistant Staphylococcus aureus ; Silver/pharmacology/therapeutic use ; Swine ; *Wound Infection/drug therapy ; }, abstract = {OBJECTIVE: The purpose of this study was to use an in vivo biofilm porcine model to examine a new polyvinyl alcohol-based gelling fibre dressing with silver and compare it to other commercial dressings containing: polyvinyl alcohol-based gelling fibre without silver; carboxymethyl cellulose-based fibre with silver, benzethonium chloride and ethylenediaminetetraacetic acid; and untreated control.

METHODS: A total of 52 deep partial-thickness wounds (10x7x0.5mm) were created on each of three animals and inoculated with 25µl of meticillin-resistant Staphylococcus aureus (MRSA) (10[6] colony forming units (CFU)/ml). Wounds were covered for 24 hours to allow biofilm formation and were randomly designated to one of the four treatments. Samples were recovered for microbiological and histological analysis on days 3, 5 and 7 post-treatment.

RESULTS: Polyvinyl alcohol-based gelling fibre dressing with silver was able to significantly reduce biofilm more effectively than the other treatment groups. By day 7, wounds treated with the dressing had a 2.72±0.01 log CFU/g reduction in MRSA count versus untreated control wounds and a 2.59±0.01 log CFU/g reduction versus baseline counts. For histology analysis, all wounds reached 100% re-epithelialisation by day 5.

CONCLUSION: The results of this study indicated that polyvinyl alcohol-based gelling fibre dressing with silver was effective against biofilm of antibiotic-resistant staphylococcal strains without inhibiting the wound healing process, and may have important clinical implications when treating acute and/or hard-to-heal wounds.}, } @article {pmid35146783, year = {2022}, author = {Yadav, MK and Yadav, P and Dhiman, M and Tewari, S and Tiwari, SK}, title = {Plantaricin LD1 purified from Lactobacillus plantarum LD1 inhibits biofilm formation of Enterococcus faecalis ATCC 29212 in tooth model.}, journal = {Letters in applied microbiology}, volume = {75}, number = {3}, pages = {623-631}, doi = {10.1111/lam.13668}, pmid = {35146783}, issn = {1472-765X}, support = {5/9/1117/2013-NUT//Indian Council of Medical Research/ ; BT/PR8911/NDB/39/423/2013//Department of Biotechnology, Ministry of Science and Technology, India/ ; }, mesh = {*Anti-Infective Agents ; *Bacteriocins/chemistry/pharmacology ; Biofilms ; Enterococcus faecalis ; *Lactobacillus plantarum ; Microbial Sensitivity Tests ; }, abstract = {Plantaricin LD1 was purified to homogeneity using activity-guided chromatography. Enterococcus faecalis ATCC 29212 was found to be sensitive to plantaricin LD1 showing 13 ± 0·21 mm zone of growth inhibition. The minimum inhibitory concentration (MIC) was found to be 50 µg ml[-1] against Ent. faecalis ATCC 29212. The in vitro biofilm formation by Ent. faecalis ATCC 29212 was observed, which was completely inhibited in the presence of bacteriocin. Similarly, biofilm formation was also observed on the teeth surface showing purple colour, whereas treated-teeth were clean and indicated no biofilm formation. Further, untreated cells of Ent. faecalis ATCC 29212 were found normal and plantaricin LD1-treated cells were ruptured when seen under light microscope, suggesting killing of target cells. These findings have proven the initial leads for antimicrobial and anti-biofilm activity of plantaricin LD1 against Ent. faecalis and its possible application for the treatment of endodontic diseases.}, } @article {pmid35146352, year = {2021}, author = {Tiseo, G and Fais, R and Forniti, A and Melandro, F and Tavanti, A and Ghelardi, E and De Simone, P and Falcone, M and Lupetti, A}, title = {Fatal fungemia by biofilm-producing Trichosporon asahii in a liver transplant candidate.}, journal = {Le infezioni in medicina}, volume = {29}, number = {3}, pages = {464-468}, pmid = {35146352}, issn = {2532-8689}, abstract = {Acute-on-chronic liver failure (ACLF) is often associated with a dismal outcome. Infections might preclude access to liver transplantation (LT) for these patients, further reducing their chance of survival. We report the case of a patient with ACLF who died before LT for biofilm-producing Trichosporon asahii fungemia. The patient early started antifungal therapy with anidulafungin, but T. asahii was not susceptible to echinocandins, delaying the start of active antifungal therapy. Although rare, invasive infections by Trichosporon spp. are associated with high mortality rates due to low antimicrobial susceptibility and production of biofilms on indwelling devices. Early diagnosis and treatment are crucial to reduce mortality and enhance patient survival.}, } @article {pmid35145849, year = {2022}, author = {Hill, T and Jain, VK and Iyengar, KP}, title = {Antimicrobial peptides (AMP) in biofilm induced orthopaedic device-related infections.}, journal = {Journal of clinical orthopaedics and trauma}, volume = {25}, number = {}, pages = {101780}, pmid = {35145849}, issn = {0976-5662}, abstract = {Orthopaedic device-related infection (ODRI) represent is one of the most challenging complications to manage in orthopaedic and trauma surgery. Biofilm formation is one of the crucial steps in the development of implant related orthopaedic infections due to the surface-adherent bacteria. Bacterial biofilms have several innate antimicrobial resistance mechanisms and hence difficult to eliminate with conventional antibiotics. Chronic, indolent, unresponsive infection can lead to clinical disability affecting quality of life with socio-economic consequences and compromised patient related health care outcomes. Although there is a basic understanding of the mechanism of biofilm associated antimicrobial resistance, enhanced knowledge, innovative treatment strategies and new therapeutic modalities is the need of the hour to manage biofilm associated Orthopaedic device-related infection (ODRI). Antimicrobial peptides (AMPs) represent an exciting opportunity to treat biofilm infections due to their diverse mechanisms of action. This article highlights the current role and mechanism of Antimicrobial peptides (AMPs) in preventing and eradicating Orthopaedic device-related infection (ODRI).}, } @article {pmid35145026, year = {2022}, author = {Béchon, N and Mihajlovic, J and Lopes, AA and Vendrell-Fernández, S and Deschamps, J and Briandet, R and Sismeiro, O and Martin-Verstraete, I and Dupuy, B and Ghigo, JM}, title = {Bacteroides thetaiotaomicron uses a widespread extracellular DNase to promote bile-dependent biofilm formation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {7}, pages = {}, pmid = {35145026}, issn = {1091-6490}, mesh = {Bacterial Proteins/genetics/*metabolism ; Bacteroides thetaiotaomicron/*enzymology/genetics/physiology ; Bile/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/genetics/metabolism ; Deoxyribonucleases/genetics/*metabolism ; Gene Expression Regulation, Bacterial/*physiology ; Gene Expression Regulation, Enzymologic/physiology ; }, abstract = {Bacteroides thetaiotaomicron is a gut symbiont that inhabits the mucus layer and adheres to and metabolizes food particles, contributing to gut physiology and maturation. Although adhesion and biofilm formation could be key features for B. thetaiotaomicron stress resistance and gut colonization, little is known about the determinants of B. thetaiotaomicron biofilm formation. We previously showed that the B. thetaiotaomicron reference strain VPI-5482 is a poor in vitro biofilm former. Here, we demonstrated that bile, a gut-relevant environmental cue, triggers the formation of biofilm in many B. thetaiotaomicron isolates and common gut Bacteroidales species. We determined that bile-dependent biofilm formation involves the production of the DNase BT3563 or its homologs, degrading extracellular DNA (eDNA) in several B. thetaiotaomicron strains. Our study therefore shows that, although biofilm matrix eDNA provides a biofilm-promoting scaffold in many studied Firmicutes and Proteobacteria, BT3563-mediated eDNA degradation is required to form B. thetaiotaomicron biofilm in the presence of bile.}, } @article {pmid35143955, year = {2022}, author = {An, SJ and Namkung, JU and Ha, KW and Jun, HK and Kim, HY and Choi, BK}, title = {Inhibitory effect of d-arabinose on oral bacteria biofilm formation on titanium discs.}, journal = {Anaerobe}, volume = {75}, number = {}, pages = {102533}, doi = {10.1016/j.anaerobe.2022.102533}, pmid = {35143955}, issn = {1095-8274}, mesh = {Arabinose/pharmacology ; Biofilms ; Fusobacterium nucleatum ; Humans ; *Peri-Implantitis ; Porphyromonas gingivalis ; *Titanium/pharmacology ; }, abstract = {OBJECTIVES: Biofilm formation on dental implant surfaces can cause peri-implant mucositis and peri-implantitis. Lectins are involved in interactions between bacteria or between bacteria and their hosts. Disrupting these interactions via specific sugars can result in reduced adhesion and biofilm formation. The purpose of this study was to identify sugars that function as antiadhesion or antibiofilm agents on titanium discs.

METHODS: Of the sugars tested, the sugars that did not affect the planktonic growth of Streptococcus oralis, Fusobacterium nucleatum, and Porphyromonas gingivalis were selected. The selected sugars were assessed for their ability to inhibit biofilm formation of bacteria in single and consortium species by crystal violet staining, confocal laser scanning microscopy after live/dead staining, and scanning electron microscopy. The sugars were evaluated for their ability to inhibit activity of the quorum sensing molecule autoinducer 2 (AI-2) by bioluminescence assay.

RESULTS: Biofilm formation of single bacteria or consortia of S. oralis, F. nucleatum, and P. gingivalis on titanium discs was significantly inhibited in the presence of d-arabinose. Pretreating titanium discs with d-arabinose for 3 min inhibited biofilm formation at a level comparable to that observed when d-arabinose was present over the entire period, suggesting that d-arabinose had initial anti-adhesive activity. In addition, d-arabinose inhibited the activity of AI-2.

CONCLUSIONS: d-Arabinose may be a good candidate for application as an antibiofilm agent and AI-2 inhibitor.}, } @article {pmid35142967, year = {2022}, author = {Zhang, H and Li, S and Cheng, Y}, title = {Antibiofilm Activity of Allicin and Quercetin in Treating Biofilm-Associated Orthopaedics Infection.}, journal = {Applied biochemistry and biotechnology}, volume = {}, number = {}, pages = {}, pmid = {35142967}, issn = {1559-0291}, abstract = {Biofilms formed by bacteria are the group of sessile microbial cells that remain encompassed by self-secreted polymeric substances and have resulted in great health-care concern. The extracellular polymeric substances (EPS) prevent the penetration of antibiotics and other drugs, thereby resulting in the development of multi-drug resistance or antibiotic resistance. The biofilm-associated prosthetics being places at the joins of bone injury are the common sites for the development of biofilm-associated infection. This often spreads and results in the development of orthopaedic infections. Most of the infections are associated with musculoskeletal system and originate from non-living surfaces. The biofilm prevents the penetration of drugs, thereby resulting in the development of antibiotic resistance or multi-drug resistance. The minimum inhibitory concentration (MIC) for allicin and quercetin was found to be 80 µg/mL for quercetin and 100 µg/mL for amoxicillin against the sessile communities of Pseudomonas aeruginosa associated with the orthopaedic infection. The role of quercetin and allicin in reduction of protein, carbohydrate and eDNA content of the exopolysaccharides (EPS) was tested. The anti-quorum sensing activity of quercetin and allicin was confirmed both by biochemical and by photomicrographic studies. The antibiofilm and antimicrobial activities of quercetin and allicin were determined both by in vitro and in silico studies on P. aeruginosa bacterial strain from biofilm-associated orthopaedic infection.}, } @article {pmid35138170, year = {2022}, author = {Aubourg, M and Pottier, M and Léon, A and Bernay, B and Dhalluin, A and Cacaci, M and Torelli, R and Ledormand, P and Martini, C and Sanguinetti, M and Auzou, M and Gravey, F and Giard, JC}, title = {Inactivation of the Response Regulator AgrA Has a Pleiotropic Effect on Biofilm Formation, Pathogenesis and Stress Response in Staphylococcus lugdunensis.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0159821}, pmid = {35138170}, issn = {2165-0497}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Humans ; Hydrogen Peroxide/pharmacology ; Male ; Mice ; Mice, Inbred BALB C ; Staphylococcal Infections/*microbiology ; Staphylococcus lugdunensis/drug effects/genetics/*pathogenicity/*physiology ; Virulence ; }, abstract = {Staphylococcus lugdunensis is a coagulase-negative Staphylococcus that emerges as an important opportunistic pathogen. However, little is known about the regulation underlying the transition from commensal to virulent state. Based on knowledge of S. aureus virulence, we suspected that the agr quorum sensing system may be an important determinant for the pathogenicity of S. lugdunensis. We investigated the functions of the transcriptional regulator AgrA using the agrA deletion mutant. AgrA played a role in cell pigmentation: ΔargA mutant colonies were white while the parental strains were slightly yellow. Compared with the wild-type strain, the ΔargA mutant was affected in its ability to form biofilm and was less able to survive in mice macrophages. Moreover, the growth of ΔagrA was significantly reduced by the addition of 10% NaCl or 0.4 mM H2O2 and its survival after 2 h in the presence of 1 mM H2O2 was more than 10-fold reduced. To explore the mechanisms involved beyond these phenotypes, the ΔagrA proteome and transcriptome were characterized by mass spectrometry and RNA-Seq. We found that AgrA controlled several virulence factors as well as stress-response factors, which are well correlated with the reduced resistance of the ΔagrA mutant to osmotic and oxidative stresses. These results were not the consequence of the deregulation of RNAIII of the agr system, since no phenotype or alteration of the proteomic profile has been observed for the ΔRNAIII mutant. Altogether, our results highlighted that the AgrA regulator of S. lugdunensis played a key role in its ability to become pathogenic. IMPORTANCE Although belonging to the natural human skin flora, Staphylococcus lugdunensis is recognized as a particularly aggressive and destructive pathogen. This study aimed to characterize the role of the response regulator AgrA, which is a component of the quorum-sensing agr system and known to be a major element in the regulation of pathogenicity and biofilm formation in Staphylococcus aureus. In the present study, we showed that, contrary to S. aureus, the agrA deletion mutant produced less biofilm. Inactivation of agrA conferred a white colony phenotype and impacted S. lugdunensis in its ability to survive in mice macrophages and to cope with osmotic and oxidative stresses. By global proteomic and transcriptomic approaches, we identified the AgrA regulon, bringing molecular bases underlying the observed phenotypes. Together, our data showed the importance of AgrA in the opportunistic pathogenic behavior of S. lugdunensis allowing it to be considered as an interesting therapeutic target.}, } @article {pmid35138127, year = {2022}, author = {Takeuchi, K and Takeuchi, M and Kakino, W and Uyeno, Y}, title = {Biofilm Bacterial Dynamics and Changes in Inorganic Nitrogen Density Due to the Presence of Freshwater Pearl Mussels.}, journal = {mSphere}, volume = {7}, number = {1}, pages = {e0083421}, pmid = {35138127}, issn = {2379-5042}, mesh = {Animals ; Biofilms ; *Bivalvia/physiology ; Chlorophyll A ; *Cyanobacteria ; Ecosystem ; Fresh Water/chemistry ; Nitrogen ; RNA, Ribosomal, 16S/genetics ; Water ; }, abstract = {The freshwater pearl mussel (genus Margaritifera) has shown severe declines, while the mussels play important roles in the translocation of nutrients and materials in river water ecosystems. We hypothesized that the biofilm bacterial composition and nutrient flow may reflect the differences in the existence of mussels. We analyzed water from 14 rivers from in multiple regions of Japan, including eight rivers, where the two species of freshwater pearl mussels (Margaritifera laevis and Margaritifera togakushiensis) are predominantly found, to analyze the microbial and nutritional nature of the biofilm artificially formed in the river. Field-produced biofilms, including the bacterial community structure, were examined, using next-generation sequencing of bacterial 16S rRNA gene amplicons followed by analyzing the genomic DNA extracted from the samples, inorganic nitrogen compounds, and chlorophyll a concentration. Compared to those in the control river without freshwater pearl mussels, biofilms of the existing river contained less inorganic nitrogen (ammonia and nitrate), suggesting the involvement of mussels in regulating the river water nutrient flow. Distinct changes were found in biofilms, depending on mussel existence, particularly in biofilms containing fewer photosynthetic bacterial groups, such as Betaproteobacteria and Cyanobacteria. Conversely, bacteria belonging to Bacteroidales in Bacteroidetes and Clostridiales in Firmicutes were predominantly found in biofilm samples where the mussels existed. Mussels alleviated strict nitrogen limitation in streams and possibly caused a concomitant change in the bacterial communities, where populations of bacterial groups exchanging inorganic nitrogen were low. We demonstrate the profound influence of freshwater mussel species on ecosystem processes and community dynamics across rivers. IMPORTANCE The abundance of freshwater unioid mussels exhibited more diverse patterns of inorganic nitrogen flow and bacterial communities than the areas without mussels. This study demonstrates the effect of mussels on different freshwater ecosystem processes with variable organismal densities and biogeochemical factors. Freshwater unionid mussels significantly affect the ecosystem and community dynamics by modulating the relationships, altering nutrient availability, and indirectly manipulating the downstream ecological members, eventually expanding their role in the river ecosystems.}, } @article {pmid35137461, year = {2022}, author = {Jaeggi, M and Gyr, S and Astasov-Frauenhoffer, M and Zitzmann, NU and Fischer, J and Rohr, N}, title = {Influence of different zirconia surface treatments on biofilm formation in vitro and in situ.}, journal = {Clinical oral implants research}, volume = {33}, number = {4}, pages = {424-432}, pmid = {35137461}, issn = {1600-0501}, support = {2019-01004//PROSEC GmbH/ ; }, mesh = {Biofilms ; *Dental Implants ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Surface Properties ; Titanium ; Zirconium ; }, abstract = {OBJECTIVES: To determine whether the surface treatment of zirconia affects biofilm formation in an in vitro three-species biofilm model and in situ.

MATERIAL AND METHODS: Zirconia surfaces considered for the transmucosal portion of a zirconia implant were compared with polished pure titanium grade 4 (Tp). Disks 13 mm in diameter of either polished (Zp), polished and heat-treated (Zpt), machined (Zm), machined and heat-treated (Zmt) and sandblasted, etched and heat-treated (Z14) zirconia were fabricated. Surface roughness and wettability of specimens was measured. Biofilm formation was evaluated by safranin staining and scanning electron microscopy (SEM) using a three-species model, and intraorally with 16 volunteers carrying oral splints in two independent experiments. Relative biofilm formation was compared with Kruskal-Wallis followed by Bonferroni post hoc test (α = 0.05).

RESULTS: In vitro biofilm formation with optical density values on Zp (0.14 ± 0.01), Zpt (0.14 ± 0.02), Zm (0.13 ± 0.01) and Zmt (0.13 ± 0.01) was significantly lower than on Tp (0.21 ± 0.05) and Z14 (0.20 ± 0.04) (p < .05). In situ biofilm formation was significantly higher on Z14 (0.56 ± 0.45) (p < .05), while no significant differences in optical density were observed among Zp (0.25 ± 0.20), Zm (0.36 ± 0.34) and Tp (0.28 ± 0.22). SEM analysis supported quantitative findings.

CONCLUSIONS: In the in vitro, three-species biofilm model differences in material and surface roughness affected biofilm formation. In situ biofilm formation was mainly affected by the surface roughness of the specimens. Polishing of zirconia is recommended to reduce biofilm formation, while heat treatment has no significant effect.}, } @article {pmid35134521, year = {2022}, author = {Zhang, H and Wu, J and Li, R and Kim, DH and Bi, X and Zhang, G and Jiang, B and Yong Ng, H and Shi, X}, title = {Novel intertidal wetland sediment-inoculated moving bed biofilm reactor treating high-salinity wastewater: Metagenomic sequencing revealing key functional microorganisms.}, journal = {Bioresource technology}, volume = {348}, number = {}, pages = {126817}, doi = {10.1016/j.biortech.2022.126817}, pmid = {35134521}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Nitrogen/analysis ; Salinity ; Waste Disposal, Fluid ; *Wastewater ; *Wetlands ; }, abstract = {In this study, two lab-scale moving bed biofilm reactors (MBBR), seeded with intertidal wetland sediment (IWS) and activated sludge (AS), were constructed to compare their performances in treating high-salinity (3%) wastewater. Under a wide range of influent TOC (178-620 mg/L) and NH4[+]-N (25-100 mg/L), both the MBBRs (Riws and Ras) exhibited excellent TOC removal efficiencies of >95%. Regarding nitrogen reduction, Riws exhibited a significantly superior TN removal efficiency of 90.2 ± 1.8% than that of Ras (76.8 ± 2.9%). A correlation analysis was innovatively conducted comparing the results between metagenomic sequencing and DNA pyrosequencing, and positive linear relationships were found with R[2] values of 0.763-0.945. Meanwhile, for illustration of different TN removal performance, nitrogen metabolic pathways were also assessed. Moreover, a list of functional oxidases (EC: 1.13.11.1, EC: 1.13.11.2, EC: 1.13.11.24, EC: 1.13.12.16, EC: 1.4.3.4, EC: 1.16.3.3, EC: 1.14.14.28) was found in IWS, revealing its potential in degradation of recalcitrant organics.}, } @article {pmid35133506, year = {2022}, author = {Özdemir, FN and Buzrul, S and Özdemir, C and Akçelik, N and Akçelik, M}, title = {Determination of an effective agent combination using nisin against Salmonella biofilm.}, journal = {Archives of microbiology}, volume = {204}, number = {3}, pages = {167}, pmid = {35133506}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Nisin/pharmacology ; Salmonella ; }, abstract = {This present study aims to determine the lowest concentration effects of the assayed different antibiotics; antimicrobial agents alone and their combinations with nisin were investigated to prevent the biofilm formation and break down the biofilm structure of Salmonella. While the combination of nisin and EDTA showed a synergistic effect against Salmonella strain, chlorhexidine digluconate and streptomycin with nisin showed a partial synergetic effect; citric acid and sulfonamides with nisin showed an indifferent effect. The use of citric acid and chlorhexidine digluconate alone was very effective in Salmonella inhibition. While the citric acid combined with other agents had not much effect, the use of chlorhexidine digluconate combined with nisin and EDTA inactivated the total initial count within 24 h. Significantly, when citric acid and sulfonamides are used alone, they reduce by 64% and 44%, respectively. When they used nisin + EDTA, this ratio increased to 83% and 84%, respectively. For the prevention of biofilm, the most suitable conditions were determined as 97% biofilm inhibition. The results of this study can be used as a guide for the emergence of new approaches to ensure the food safety and quality of the food industry.}, } @article {pmid35133020, year = {2022}, author = {Medina Lopez, AI and Fregoso, DR and Gallegos, A and Yoon, DJ and Fuentes, JJ and Crawford, R and Kaba, H and Yang, HY and Isseroff, RR}, title = {Beta adrenergic receptor antagonist can modify Pseudomonas aeruginosa biofilm formation in vitro: Implications for chronic wounds.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {36}, number = {3}, pages = {e22057}, doi = {10.1096/fj.202100717RR}, pmid = {35133020}, issn = {1530-6860}, support = {UL1 TR001860/TR/NCATS NIH HHS/United States ; }, mesh = {Adrenergic Antagonists/*pharmacology/therapeutic use ; *Biofilms ; Epinephrine/*pharmacology/therapeutic use ; Humans ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Skin Diseases, Bacterial/drug therapy/microbiology ; Timolol/*pharmacology/therapeutic use ; *Wound Healing ; }, abstract = {Non-healing wounds are a major medical challenge, affecting over 6.5 million people in the US alone, with associated healthcare costs of about $16 billion annually. They can result in prolonged hospitalizations, work loss, disability, poor quality of life, and in diabetic patients with foot ulcers, amputation of the affected limb in 25% of patients. Though chronic ulcers may arise from different underlying diseases, the unifying feature is chronic infection, driving persistent inflammation that prolongs the healing process. One of the most frequently cultured or genetically identified pathogens in skin wounds is Pseudomonas aeruginosa. This species avidly forms biofilms in the wound that impede bacterial eradication by the host's immune mechanisms and limit efficacy of systemic antibiotics. Thus, non-antibiotic approaches to limit the growth and biofilm formation of this wound pathogen would be an advance in the treatment of chronic wounds. Prior work has demonstrated that the growth of other microbial species can be modulated by catecholamine agonists and antagonists of the adrenergic receptors (ARs). Here, we demonstrate that not only can the growth of this common wound pathogen be modulated by catecholamines, but also that the beta-AR antagonists can significantly decrease their growth, and importantly, limit their ability to form biofilms. These findings suggest that beta adrenergic antagonists may have a therapeutic role in the treatment of chronic skin wounds.}, } @article {pmid35131456, year = {2022}, author = {Jiang, L and Ji, F and Liao, Y and Mao, Y and Shen, Q and Zhuo, Y and Zhang, Q}, title = {Denitrification performance and mechanism of denitrification biofilm reactor based on carbon-nitrate counter-diffusional.}, journal = {Bioresource technology}, volume = {348}, number = {}, pages = {126804}, doi = {10.1016/j.biortech.2022.126804}, pmid = {35131456}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; *Nitrates/metabolism ; Nitrogen ; }, abstract = {This study researched denitrification performance and mechanism of denitrification biofilm reactor with different HRTs and carbon sources dosages. Experimental group (EG) had better nitrate and COD removal performance than control group (CG) with different HRTs or carbon doses, and the maximum nitrate-to-nitrite transformation ratio (NTR) of them reached 7.91 ± 1.60% and 17.50 ± 1.92%, respectively. Because organic carbon sources were added to the carrier's interior in EG, forming high local concentrations in biofilms and counter-diffusional with nitrate. By contrast, carbon sources and nitrate were provided from the aqueous phase in CG. Thus, the EG system has more active regions of the biofilm than CG. In addition, EG had higher proportions of microorganisms and enzymes related to denitrification and carbon metabolism. The most dominant phylum, genus, and species were Proteobacteria, Thaurea, and Thauera_sp._27, respectively. The transcript of acetyl-CoA synthetase (K01895) and denitrification (M00529) was mainly originated from unclassified_g__Pseudomonas and unclassified_g__Thauera, respectively.}, } @article {pmid35130730, year = {2021}, author = {Miller, AL and Nicastro, LK and Bessho, S and Grando, K and White, AP and Zhang, Y and Queisser, G and Buttaro, BA and Tükel, Ç}, title = {Nitrate Is an Environmental Cue in the Gut for Salmonella enterica Serovar Typhimurium Biofilm Dispersal through Curli Repression and Flagellum Activation via Cyclic-di-GMP Signaling.}, journal = {mBio}, volume = {13}, number = {1}, pages = {e0288621}, pmid = {35130730}, issn = {2150-7511}, support = {R01 AI153325/AI/NIAID NIH HHS/United States ; R21 AI148770/AI/NIAID NIH HHS/United States ; R21 AI151893/AI/NIAID NIH HHS/United States ; }, mesh = {Humans ; *Salmonella typhimurium/metabolism ; *Salmonella enterica/metabolism ; Nitrates ; Bacterial Proteins/metabolism ; Serogroup ; Cues ; Biofilms ; Cyclic GMP ; Flagella/physiology ; Inflammation ; Gene Expression Regulation, Bacterial ; }, abstract = {Curli, a major component of the bacterial biofilms in the intestinal tract, activates pattern recognition receptors and triggers joint inflammation after infection with Salmonella enterica serovar Typhimurium. The factors that allow S. Typhimurium to disperse from biofilms and invade the epithelium to establish a successful infection during acute inflammation remain unknown. Here, we studied S. Typhimurium biofilms in vitro and in vivo to understand how the inflammatory environment regulates the switch between multicellular and motile S. Typhimurium in the gut. We discovered that nitrate generated by the host is an environmental cue that induces S. Typhimurium to disperse from the biofilm. Nitrate represses production of an important biofilm component, curli, and activates flagella via the modulation of intracellular cyclic-di-GMP levels. We conclude that nitrate plays a central role in pathogen fitness by regulating the sessile-to-motile lifestyle switch during infection. IMPORTANCE Recent studies provided important insight into our understanding of the role of c-di-GMP signaling and the regulation of enteric biofilms. Despite an improved understanding of how c-di-GMP signaling regulates S. Typhimurium biofilms, the processes that affect the intracellular c-di-GMP levels and the formation of multicellular communities in vivo during infections remain unknown. Here, we show that nitrate generated in the intestinal lumen during infection with S. Typhimurium is an important regulator of biofilm formation in vivo.}, } @article {pmid35129864, year = {2022}, author = {Sánchez, MC and Velapatiño, A and Llama-Palacios, A and Valdés, A and Cifuentes, A and Ciudad, MJ and Collado, L}, title = {Metataxonomic and metabolomic evidence of biofilm homeostasis disruption related to caries: An in vitro study.}, journal = {Molecular oral microbiology}, volume = {37}, number = {2}, pages = {81-96}, pmid = {35129864}, issn = {2041-1014}, mesh = {Biofilms ; *Dental Caries/microbiology ; *Dental Caries Susceptibility ; Homeostasis ; Humans ; Metabolomics ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The ecological dysbiosis of a biofilm includes not only bacterial changes but also changes in their metabolism. Related to oral biofilms, changes in metabolic activity are crucial endpoint, linked directly to the pathogenicity of oral diseases. Despite the advances in caries research, detailed microbial and metabolomic etiology is yet to be fully clarified. To advance this knowledge, a meta-taxonomic approach based on 16S rRNA gene sequencing and an untargeted metabolomic approach based on an ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis (UHPLC/Q-TOF-MS) were conducted. To this end, an in vitro biofilm model derived from the saliva of healthy participants were developed, under commensal and cariogenic conditions by adding sucrose as the disease trigger. The cariogenic biofilms showed a significant increase of Firmicutes phyla (p = 0.019), due to the significant increase in the genus Streptococcus (p = 0.010), and Fusobacter (p < 0.001), by increase Fusobacterium (p < 0.001) and Sphingomonas (p = 0.024), while suffered a decrease in Actinobacteria (p < 0.001). As a consequence of the shift in microbiota composition, significant extracellular metabolomics changes were detected, showed 59 metabolites of the 120 identified significantly different in terms of relative abundance between the cariogenic/commensal biofilms (Rate of change > 2 and FDR < 0.05). Forty-two metabolites were significantly higher in abundance in the cariogenic biofilms, whereas 17 metabolites were associated significantly with the commensal biofilms, principally related protein metabolism, with peptides and amino acids as protagonists, latter represented by histidine, arginine, l-methionine, glutamic acid, and phenylalanine derivatives.}, } @article {pmid35129699, year = {2022}, author = {Letieri, AS and Freitas-Fernandes, LB and Souza, IPR and Valente, AP and Fidalgo, TKS}, title = {Metabolomic Signatures of In Vitro Biofilm Maturation of Streptococcus mutans.}, journal = {Current microbiology}, volume = {79}, number = {3}, pages = {86}, pmid = {35129699}, issn = {1432-0991}, mesh = {Biofilms ; *Dental Caries ; Humans ; Metabolomics ; *Streptococcus mutans ; Sucrose ; }, abstract = {The Streptococcus mutans is commonly find in oral environment in both symbiont and dysbiotic conditions, where for the last one it causes the break in homeostatic balance and, in association with other microorganisms' community, results in dental caries process. Additionally, it is important to determine the low molecular weight metabolites profile from Streptococcus mutans to distinguish the endogenous and exogenous compounds from patient subjected to salivary metabolomic studies. Thus, the objective of the present study was to characterize the in vitro metabolomic profile of the maturation of a single-species Streptococcus mutans biofilm using metabolomic approach by [1]H-nuclear magnetic resonance (NMR) spectroscopy. A distinct metabolomic profile was observed after 2 days of biofilm maturation, independently of the presence of enamel substrate. Sucrose, lactate, and fructose were the main metabolites responsible for the distinction. The sucrose was consumed by S. mutans in higher levels in the initial experimental periods than at 6 days of biofilm growth. Lactate and fructose were the main compounds secreted, regardless of the type of growth, but it was also observed production of propionate, iso-butyrate, and pyruvate. Pyruvate metabolism and glycolysis/gluconeogenesis were the main pathways related to biofilm growth. The results contribute to the determination of compounds that are resulted from oral microbial activity and help to guide further metabolomics studies.}, } @article {pmid35129518, year = {2023}, author = {Sinha, M and Ghosh, N and Wijesinghe, DS and Mathew-Steiner, SS and Das, A and Singh, K and El Masry, M and Khanna, S and Inoue, H and Yamazaki, K and Kawada, M and Gordillo, GM and Roy, S and Sen, CK}, title = {Pseudomonas Aeruginosa Theft Biofilm Require Host Lipids of Cutaneous Wound.}, journal = {Annals of surgery}, volume = {277}, number = {3}, pages = {e634-e647}, pmid = {35129518}, issn = {1528-1140}, support = {R01 NS085272/NS/NINDS NIH HHS/United States ; R01 NS042617/NS/NINDS NIH HHS/United States ; R01 GM108014/GM/NIGMS NIH HHS/United States ; R01 NR015676/NR/NINR NIH HHS/United States ; R01 DK114718/DK/NIDDK NIH HHS/United States ; U01 DK119099/DK/NIDDK NIH HHS/United States ; R01 DK125835/DK/NIDDK NIH HHS/United States ; R01 DK128845/DK/NIDDK NIH HHS/United States ; U24 DK122927/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Ceramidases ; Lower Extremity ; *PPAR delta ; *Pseudomonas aeruginosa ; Swine ; }, abstract = {OBJECTIVE: This work addressing complexities in wound infection, seeks to test the reliance of bacterial pathogen Pseudomonas aeruginosa (PA) on host skin lipids to form biofilm with pathological consequences.

BACKGROUND: PA biofilm causes wound chronicity. Both CDC as well as NIH recognizes biofilm infection as a threat leading to wound chronicity. Chronic wounds on lower extremities often lead to surgical limb amputation.

METHODS: An established preclinical porcine chronic wound biofilm model, infected with PA or Pseudomonas aeruginosa ceramidase mutant (PA ∆Cer), was used.

RESULTS: We observed that bacteria drew resource from host lipids to induce PA ceramidase expression by three orders of magnitude. PA utilized product of host ceramide catabolism to augment transcription of PA ceramidase. Biofilm formation was more robust in PA compared to PA ∆Cer . Downstream products of such metabolism such as sphingosine and sphingosine-1-phosphate were both directly implicated in the induction of ceramidase and inhibition of peroxisome proliferator-activated receptor (PPAR)δ, respectively. PA biofilm, in a ceram-idastin-sensitive manner, also silenced PPARδ via induction of miR-106b. Low PPARδ limited ABCA12 expression resulting in disruption of skin lipid homeostasis. Barrier function of the wound-site was thus compromised.

CONCLUSIONS: This work demonstrates that microbial pathogens must co-opt host skin lipids to unleash biofilm pathogenicity. Anti-biofilm strategies must not necessarily always target the microbe and targeting host lipids at risk of infection could be productive. This work may be viewed as a first step, laying fundamental mechanistic groundwork, toward a paradigm change in biofilm management.}, } @article {pmid35128791, year = {2022}, author = {Xu, LC and Siedlecki, CA}, title = {Submicron topography design for controlling staphylococcal bacterial adhesion and biofilm formation.}, journal = {Journal of biomedical materials research. Part A}, volume = {110}, number = {6}, pages = {1238-1250}, pmid = {35128791}, issn = {1552-4965}, support = {R21 AI139706/AI/NIAID NIH HHS/United States ; R01 HL153231/HL/NHLBI NIH HHS/United States ; }, mesh = {*Bacterial Adhesion ; *Biofilms ; Staphylococcus ; Staphylococcus epidermidis/physiology ; Surface Properties ; }, abstract = {Surface topography modification with nano- or micro-textured structures has been an efficient approach to inhibit microbial adhesion and biofilm formation and thereby to prevent biomaterial-associated infection without modification of surface chemistry/bulk properties of materials and without causing antibiotic resistance. This manuscript focuses on submicron-textured patterns with ordered arrays of pillars on polyurethane (PU) biomaterial surfaces in an effort to understand the effects of surface pillar features and surface properties on adhesion and colonization responses of two staphylococcal strains. Five submicron patterns with a variety of pillar dimensions were designed and fabricated on PU film surfaces and bacterial adhesion and biofilm formation of Staphylococcal strains (Staphylococcus epidermidis RP62A and Staphylococcus aureus Newman D2C) were characterized. Results show that all submicron textured surface significantly reduced bacterial adhesion and inhibited biofilm formation, and bacterial adhesion linearly decreased with the reduction in top surface area fraction. Surface wettability did not show a linear correlation with bacterial adhesion, suggesting that surface contact area dominates bacterial adhesion. From this, it appears that the design of textured patterns should minimize surface area fraction to reduce the bacterial interaction with surfaces but in a way that ensures the mechanical strength of pillars in order to avoid collapse. These findings may provide a rationale for design of polymer surfaces for antifouling medical devices.}, } @article {pmid35127553, year = {2021}, author = {Priya, A and Nivetha, S and Pandian, SK}, title = {Synergistic Interaction of Piperine and Thymol on Attenuation of the Biofilm Formation, Hyphal Morphogenesis and Phenotypic Switching in Candida albicans.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {780545}, pmid = {35127553}, issn = {2235-2988}, mesh = {Alkaloids ; Antifungal Agents/pharmacology ; Benzodioxoles ; Biofilms ; *Candida albicans ; Hyphae ; Morphogenesis ; Piperidines ; Polyunsaturated Alkamides ; *Thymol/pharmacology ; }, abstract = {The incidence of fungal infections has significantly increased in recent years due to the emergence of antifungal resistance. Biofilm formation is considered to be a major contributor to both the infectious diseases and to antimicrobial resistance. Consequently, biofilm-associated infections are often problematic to treat with existing therapeutics. Adhesion of C. albicans to the host surface or implanted materials followed by hyphal invasion and biofilm formation enhances C. albicans pathogenicity and virulence. Thus, developing a therapeutic agent that inhibits candidal adherence, biofilm development and morphological switching could improve clinical management of infections. The present investigation studied two emerging and alternatives strategies, namely antibiofilm and combinatorial approach, to attenuate biofilm formation and the expression of Candida virulence factors. Piperine and thymol are major bioactive components of pepper and thyme, respectively. These phytochemicals are known to possess numerous biological activities, including recently reported antibiofilm effects against C. albicans. The minimum biofilm inhibitory concentration (MBIC) of both phytochemicals was determined to be 32 µg/ml. The phytochemical treatment of Candida biofilms using piperine and thymol revealed synergistic effects at four different combinations of concentrations, i.e. 8 and 8, 8 and 4, 8 and 2 and 4 and 8 µg/ml. These synergistic combinations resulted in the significant reduction in adherence of Candida, hyphal extension and morphological transformation. Moreover, limited exposure of synergistic combinations controlled the hyphal elongation. Results were validated through the gene expression analysis. Results from the present investigation suggest that piperine and thymol can be synergistically employed for the treatment of biofilm-associated C. albicans infection.}, } @article {pmid35126986, year = {2022}, author = {Nagaraj, M and Najarzadeh, Z and Pansieri, J and Biverstål, H and Musteikyte, G and Smirnovas, V and Matthews, S and Emanuelsson, C and Johansson, J and Buxbaum, JN and Morozova-Roche, L and Otzen, DE}, title = {Chaperones mainly suppress primary nucleation during formation of functional amyloid required for bacterial biofilm formation.}, journal = {Chemical science}, volume = {13}, number = {2}, pages = {536-553}, pmid = {35126986}, issn = {2041-6520}, abstract = {Unlike misfolding in neurodegenerative diseases, aggregation of functional amyloids involved in bacterial biofilm, e.g. CsgA (E. coli) and FapC (Pseudomonas), is carefully regulated. However, it is unclear whether functional aggregation is inhibited by chaperones targeting pathological misfolding and if so by what mechanism. Here we analyze how four entirely different human chaperones or protein modulators (transthyretin, S100A9, Bri2 BRICHOS and DNAJB6) and bacterial CsgC affect CsgA and FapC fibrillation. CsgA is more susceptible to inhibition than FapC and the chaperones vary considerably in the efficiency of their inhibition. However, mechanistic analysis reveals that all predominantly target primary nucleation rather than elongation or secondary nucleation, while stoichiometric considerations suggest that DNAJB6 and CsgC target nuclei rather than monomers. Inhibition efficiency broadly scales with the chaperones' affinity for monomeric CsgA and FapC. The chaperones tend to target the most aggregation-prone regions of CsgA, but do not display such tendencies towards the more complex FapC sequence. Importantly, the most efficient inhibitors (Bri2 BRICHOS and DNAJB6) significantly reduce bacterial biofilm formation. This commonality of chaperone action may reflect the simplicity of functional amyloid formation, driven largely by primary nucleation, as well as the ability of non-bacterial chaperones to deploy their proteostatic capacities across biological kingdoms.}, } @article {pmid35123230, year = {2022}, author = {Mirzaei, R and Alikhani, MY and Arciola, CR and Sedighi, I and Yousefimashouf, R and Bagheri, KP}, title = {Prevention, inhibition, and degradation effects of melittin alone and in combination with vancomycin and rifampin against strong biofilm producer strains of methicillin-resistant Staphylococcus epidermidis.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {147}, number = {}, pages = {112670}, doi = {10.1016/j.biopha.2022.112670}, pmid = {35123230}, issn = {1950-6007}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Drug Therapy, Combination ; Genes, Bacterial ; HEK293 Cells ; Humans ; Melitten/administration & dosage/*pharmacology ; *Methicillin Resistance ; Microbial Sensitivity Tests ; Rifampin/administration & dosage/pharmacology ; Staphylococcus epidermidis/*drug effects ; Vancomycin/administration & dosage/pharmacology ; }, abstract = {Methicillin-resistant Staphylococcus epidermidis (MRSE) bacteria are being recognized as true pathogens as they are able to resist methicillin and commonly form biofilms. Recent studies have shown that antimicrobial peptides (AMPs) are promising agents against biofilm-associated bacterial infections. In this study, we aimed to explore the antibiofilm activity of melittin, either alone or in combination with vancomycin and rifampin, against biofilm-producing MRSE strains. Minimum biofilm preventive concentration (MBPC), minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC), as well as fractional biofilm preventive-, inhibitory-, and eradication concentrations (FBPCi, FBICi, and FBECi), were determined for the antimicrobial agents tested. Cytotoxicity and hemolytic activity of melittin at its synergistic concentration were examined on human embryonic kidney cells (HEK-293) and Red Blood Cells (RBCs), respectively. The effect of melittin on the downregulation of biofilm-associated genes was explored using Real-Time PCR. MBPC, MBIC, and MBEC values for melittin were in the range of 0.625-20, 0.625-20, and 10-40 μg/μL, respectively. Melittin showed high synergy (FBPCi, FBICi and FBECi < 0.5). The synergism resulted in a 64-512-fold, 2-16 and 2-8-fold reduction in melittin, rifampicin and vancomycin concentrations, respectively. The synergistic melittin concentration found to be effective did not manifest either cytotoxicity on HEK-293 or hemolytic activity on RBCs. Results showed that melittin downregulated the expression of biofilm-associated icaA, aap, and psm genes in all isolates tested, ranging from 0.04-folds to 2.11-folds for icaA and from 0.05 to 3.76-folds for aap and psm. The preventive and therapeutic indexes of melittin were improved 8-fold when combined with vancomycin and rifampin. Based on these findings, the combination of melittin with conventional antibiotics could be proposed for treating or preventing biofilm-associated MRSE infections.}, } @article {pmid35122818, year = {2022}, author = {Du, B and Wang, S and Chen, G and Wang, G and Liu, L}, title = {Nutrient starvation intensifies chlorine disinfection-stressed biofilm formation.}, journal = {Chemosphere}, volume = {295}, number = {}, pages = {133827}, doi = {10.1016/j.chemosphere.2022.133827}, pmid = {35122818}, issn = {1879-1298}, mesh = {Biofilms ; *Chlorine/pharmacology ; *Disinfection ; Ecosystem ; Nutrients ; }, abstract = {Bacterial surface attachment and subsequent biofilm expansion represent an essential adaptation to environmental signals and stresses, which are of great concern for many natural and engineered ecosystems. Yet the underlying mechanisms and driving forces of biofilm formation in a chlorinated and nutrient-restricted system remain sketchy. In this study, we coupled an experimental investigation and modeling simulation to understand how chlorination and nutrient limitation conspire to form biofilm using Pseudomonas aeruginosa as a model bacterium. Experimental results showed that moderate chlorination at 1.0 mg/L led to biofilm development amplified to 2.6 times of those without chlorine, while additional nutrient limitation (of 1/50-diluted or 0.4 g/L LB broth culture) achieved 4.6 times increment as compared to those of undiluted scenarios (of 20 g/L LB broth culture) with absence of chlorination after 24 h exposure. Meanwhile, intermediate chlorination stimulated instant flagellar motility and subsequently extracellular polymeric substances (EPS) secretion, particularly under limited nutrient condition (of 1/50-diluted or 0.4 g/L LB broth culture) that retarded chlorine consumption and provoked bacterial nutrient-limitation response. From our simulations, chlorine and resource levels along with associated spatio-temporal variations collectively drove bacterial cell movement and EPS excretion. Our results demonstrated that restraining nutrient intensified chlorination-excited cell movement and EPS production that reinforced biological and cell-surface interactions, thereby encouraging bacterial surface attachment and subsequent biofilm development. The findings provide the insights into the linkage of disinfectant and nutrient-regulated bacterial functional responses with consequent micro-habitats and biofilm dynamics.}, } @article {pmid35122470, year = {2022}, author = {Villa, K and Sopha, H and Zelenka, J and Motola, M and Dekanovsky, L and Beketova, DC and Macak, JM and Ruml, T and Pumera, M}, title = {Enzyme-Photocatalyst Tandem Microrobot Powered by Urea for Escherichia coli Biofilm Eradication.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {18}, number = {36}, pages = {e2106612}, doi = {10.1002/smll.202106612}, pmid = {35122470}, issn = {1613-6829}, mesh = {*Biofilms ; Catalysis ; *Escherichia coli ; Humans ; *Robotics ; *Titanium/pharmacology ; Urea/pharmacology ; Urease/pharmacology ; }, abstract = {Urinary-based infections affect millions of people worldwide. Such bacterial infections are mainly caused by Escherichia coli (E. coli) biofilm formation in the bladder and/or urinary catheters. Herein, the authors present a hybrid enzyme/photocatalytic microrobot, based on urease-immobilized TiO2 /CdS nanotube bundles, that can swim in urea as a biocompatible fuel and respond to visible light. Upon illumination for 2 h, these microrobots are able to remove almost 90% of bacterial biofilm, due to the generation of reactive radicals, while bare TiO2 /CdS photocatalysts (non-motile) or urease-coated microrobots in the dark do not show any toxic effect. These results indicate a synergistic effect between the self-propulsion provided by the enzyme and the photocatalytic activity induced under light stimuli. This work provides a photo-biocatalytic approach for the design of efficient light-driven microrobots with promising applications in microbiology and biomedicine.}, } @article {pmid35122191, year = {2022}, author = {Dakheel, KH and Abdul Rahim, R and Al-Obaidi, JR and Neela, VK and Hun, TG and Mat Isa, MN and Razali, N and Yusoff, K}, title = {Proteomic analysis revealed the biofilm-degradation abilities of the bacteriophage UPMK_1 and UPMK_2 against Methicillin-resistant Staphylococcus aureus.}, journal = {Biotechnology letters}, volume = {44}, number = {3}, pages = {513-522}, pmid = {35122191}, issn = {1573-6776}, support = {FRGS/1/2015/SGOS/UPM/01/2//Ministry of Higher Education, Malaysia/ ; }, mesh = {Anti-Bacterial Agents ; *Bacteriophages/genetics ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Proteomics ; }, abstract = {OBJECTIVE: The degradation activity of two bacteriophages UPMK_1 and UPMK_2 against methicillin-resistant Staphylococcus aureus phages were examined using gel zymography.

METHODS: The analysis was done using BLASTP to detect peptides catalytic domains. Many peptides that are related to several phage proteins were revealed.

RESULTS: UPMK_1 and UPMK_2 custom sequence database were used for peptide identification. The biofilm-degrading proteins in the bacteriophage UPMK_2 revealed the same lytic activity towards polysaccharide intercellular adhesin-dependent and independent of Methicillin-resistant Staphylococcus aureus (MRSA) biofilm producers in comparison to UPMK_1, which had lytic activity restricted solely to its host.

CONCLUSION: Both bacteriophage enzymes were involved in MRSA biofilm degradation during phage infection and they have promising enzybiotics properties against MRSA biofilm formation.}, } @article {pmid35121293, year = {2022}, author = {Nagliate, PC and Meili, L}, title = {Comments on "Environmental behaviors of microplastics in aquatic systems: A systematic review on degradation, adsorption, toxicity and biofilm under aging conditions" [J. Hazard. Mater. 423 (2022) 126915].}, journal = {Journal of hazardous materials}, volume = {429}, number = {}, pages = {128307}, doi = {10.1016/j.jhazmat.2022.128307}, pmid = {35121293}, issn = {1873-3336}, mesh = {Adsorption ; Biofilms ; *Microplastics/toxicity ; Plastics/toxicity ; *Water Pollutants, Chemical/analysis/toxicity ; }, } @article {pmid35119531, year = {2022}, author = {Awdhesh Kumar Mishra, R and Kodiveri Muthukaliannan, G}, title = {Role of microalgal metabolites in controlling quorum-sensing-regulated biofilm.}, journal = {Archives of microbiology}, volume = {204}, number = {3}, pages = {163}, pmid = {35119531}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; *Microalgae ; Quorum Sensing ; Virulence ; }, abstract = {Bacterial infections are primarily caused due to the formation of biofilms on the surfaces. The formation of bacterial biofilms results in 60-70% of nosocomial infections in hospital-acquired infections for multidrug-resistant bacteria. Quorum-sensing (QS) is the process of cell-cell communications among bacterial cells. The formation and regulation of biofilm-producing signaling molecules, competence for DNA uptake and factors responsible for virulence occur. When the bacterial cell population density increases, auto-inducers bind with QS receptors and induce gene expression. To suppress the expression of the virulence genes, certain antibiotics and small molecules are used against the pathogenic bacteria. Since the microorganisms are becoming resistant to antibiotics, there is a need of new compounds or molecules which can suppress or inhibit the expression or regulation of virulence genes. Microalgae are an important and rich source of bioactive compounds which have the antimicrobial property. Microalgae have various antibacterial metabolites, such as Portoamides (peptides), flavonoids, eicosapentaenoic acid, alkaloids, peptides and many other secondary metabolites. This review focuses on the signaling molecule-regulated QS mechanism, biofilm formation, and microalgae compounds' effects against pathogenic bacteria. Consequently, most of the compounds have made it to the different levels of clinical trials, even some of the compounds are used therapeutically. Despite the promising applications of antibacterial peptides and the importance of searching for new natural sources of antibiotics, limitations persist for their pharmaceutical applications. However, given due research impetus, these marine metabolites might emerge as a new wave of promising drugs.}, } @article {pmid35119288, year = {2022}, author = {Sinha, SD and Choudhuri, M and Basu, T and Gupta, D and Datta, A}, title = {Decisive Role of Polymer-Bovine Serum Albumin Interactions in Biofilm Substrates on "Philicity" and Extracellular Polymeric Substances Composition.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {38}, number = {6}, pages = {1966-1976}, doi = {10.1021/acs.langmuir.1c00187}, pmid = {35119288}, issn = {1520-5827}, mesh = {Biofilms ; Escherichia coli ; *Extracellular Polymeric Substance Matrix ; Polymers/chemistry ; *Serum Albumin, Bovine ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Formation of extracellular polymeric substances (EPS) is a crucial step for bacterial biofilm growth. The dependence of EPS composition on growth substrate and conditioning of the latter is thus of primary importance. We present results of studies on the growth of biofilms of two different strains each, of the Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, on four polymers used commonly in indwelling medical devices ─polyethene, polypropylene, polycarbonate, and polytetrafluoroethylene─immersed in bovine serum albumin (BSA) for 24 h. The polymer substrates are studied before and after immersing in BSA for 9 and 24 h, using contact angle measurement (CAM) and field emission scanning electron microscopy (FE-SEM) to extract, respectively, the "philicity" φ (defined as -cos θ, where θ is the contact angle of the liquid on the solid at a particular temperature and ambient pressure) and spatial Hirsch parameter H (defined from the relation F(r) ∼ r[2H], where F(r) is the mean squared density fluctuation at the sample surface). H = 0.5, <0.5, or >0.5 signifies no correlation, anticorrelation, and correlation, respectively. The substrates are seen to transform from large hydrophobicity to near amphiphilicity with the formation of a BSA conditioning surface layer, and the H-values distinguish the length scales of 100, 500, and 2000 nm, with the anticorrelation increasing with length scale. Biofilms of E. coli did not grow on bare PTFE and HDPE substrates. Biofilms grown on BSA-covered surfaces are studied with CAM, FE-SEM, Fourier transform infrared (FTIR), and surface-enhanced Raman spectroscopy (SERS). Both spectra and φ-values were independent of bacterial species but dependent on the polymer, while H-values show some bacterial variation. Thus, EPS composition and wetting properties of the corresponding bacterial biofilms seem to be decided by the interaction of the conditioning BSA layer with the specific polymer substrate.}, } @article {pmid35115555, year = {2022}, author = {Depetris, A and Tagliavini, G and Peter, H and Kühl, M and Holzner, M and Battin, TJ}, title = {Biophysical properties at patch scale shape the metabolism of biofilm landscapes.}, journal = {NPJ biofilms and microbiomes}, volume = {8}, number = {1}, pages = {5}, pmid = {35115555}, issn = {2055-5008}, mesh = {*Biofilms ; Ecosystem ; *Rivers ; }, abstract = {Phototrophic biofilms form complex spatial patterns in streams and rivers, yet, how community patchiness, structure and function are coupled and contribute to larger-scale metabolism remains unkown. Here, we combined optical coherence tomography with automated O2 microprofiling and amplicon sequencing in a flume experiment to show how distinct community patches interact with the hydraulic environment and how this affects the internal distribution of oxygen. We used numerical simulations to derive rates of community photosynthetic activity and respiration at the patch scale and use the obtained parameter to upscale from individual patches to the larger biofilm landscape. Our biofilm landscape approach revealed evidence of parallels in the structure-function coupling between phototrophic biofilms and their streambed habitat.}, } @article {pmid35115240, year = {2022}, author = {Koshikawa, T and Abe, M and Nagi, M and Miyazaki, Y and Takemura, H}, title = {Biofilm-formation capability depends on environmental oxygen concentrations in Candida species.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {28}, number = {5}, pages = {643-650}, doi = {10.1016/j.jiac.2022.01.010}, pmid = {35115240}, issn = {1437-7780}, mesh = {Biofilms ; *Candida/genetics ; *Candida albicans/genetics ; Candida tropicalis/genetics ; Humans ; Oxygen ; }, abstract = {BACKGROUND: Although oxygen concentrations inside of the human body vary depending on organs or tissues, few reports describe the relationships between biofilm formation of Candida species and oxygen concentrations. In this study, we investigated the biofilm-forming capabilities of Candida species under various oxygen conditions.

METHODS: We evaluated the adhesion and biofilm formation of Candida albicans and C. tropicalis under aerobic, microaerobic (oxygen concentration 5%), or anaerobic conditions. We also examined how oxygen concentration affects adhesion/maturation by changing adhesion/maturation phase conditions. We used crystal violet assay to estimate the approximate biofilm size, performed microscopic observation of biofilm morphology, and evaluated adhesion-associated gene expression.

RESULTS: The adhered amount was relatively small except for a clinical strain of C. tropicalis. Our biofilm-formation analysis showed that C. albicans formed a higher-size biofilm under aerobic conditions, while C. tropicalis favored microaerobic conditions to form mature biofilms. Our microscopic observations were consistent with these biofilm-formation analysis results. In particular, C. tropicalis exhibited more hyphal formation under microaerobic conditions. By changing the adhesion/maturation phase conditions, we represented that C. albicans had favorable biofilm-formation capability under aerobic conditions, while C. tropicalis showed enhanced biofilm formation under microaerobic adhesion conditions. In good agreement with these results, the C. tropicalis adhesion-associated gene expression tended to be higher under microaerobic or anaerobic conditions.

CONCLUSIONS: C. albicans favored aerobic conditions to form biofilms, whereas C. tropicalis showed higher biofilm-formation ability and promoted hyphal growth under microaerobic conditions. These results indicate that favorable oxygen conditions significantly differ for each Candida species.}, } @article {pmid35114554, year = {2022}, author = {Su, Y and Jiang, L and Chen, D and Yu, H and Yang, F and Guo, Y and Xie, Y and Yao, W}, title = {In vitro and in silico approaches to investigate antimicrobial and biofilm removal efficacies of combined ultrasonic and mild thermal treatment against Pseudomonas fluorescens.}, journal = {Ultrasonics sonochemistry}, volume = {83}, number = {}, pages = {105930}, pmid = {35114554}, issn = {1873-2828}, mesh = {Anti-Bacterial Agents ; Biofilms ; Bioreactors ; *Pseudomonas fluorescens/physiology ; Ultrasonics ; }, abstract = {A combined ultrasonic and thermal (US-TM) treatment was developed in this study to achieve a high efficacy of P. fluorescens biofilm control. The present study demonstrated that combined a moderate ultrasound treatment (power ≥ 80 W) and a mild heat (up to 50 °C) largely destroyed biofilm structure in 15 min and removed>65.63% of biofilm from a glass slide where cultivated the P. fluorescens biofilm. Meanwhile, the viable cell count was decreased from 10.72 to 6.48 log10CUF/mL. Differences in biofilm removal and lethal modes of US-TM treatment were confirmed through microscopies analysis in vitro. The ultrasound first contributed to releasing the bacteria in the biofilm to the environment and simultaneously exposing inner bacteria at the deep layer of biofilm depending on shear force, shock waves, acoustic streaming, etc. When the biofilm structure was destroyed, US-TM treatment would synergistically inactivate P. fluorescens cells. In silico studies adopted COMSOL to simulate acoustic pressure and temperature distribution in the bioreactor; both of them were significantly influenced by various factors, such as input power, sonotrode position, materials and volume of container, etc. Facing the biofilm issue existing on the surface of container, boundary conditions were exported and thereby pointing out potential "dead ends" where the ultrasound may not be effectively transduced. Both in vitro and in silico results may inspire the food industry to adopt US-TM treatment to achieve biofilm control.}, } @article {pmid35112272, year = {2022}, author = {Grakh, K and Mittal, D and Prakash, A and Jindal, N}, title = {Characterization and antimicrobial susceptibility of biofilm-producing Avian Pathogenic Escherichia coli from broiler chickens and their environment in India.}, journal = {Veterinary research communications}, volume = {46}, number = {2}, pages = {537-548}, pmid = {35112272}, issn = {1573-7446}, support = {F. No. AS/1/1/2017-ASR-IV//indian council of agricultural research/ ; }, mesh = {Agar ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Chickens/microbiology ; Escherichia coli/genetics ; *Escherichia coli Infections/microbiology/veterinary ; Poultry ; *Poultry Diseases/epidemiology ; Water ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is responsible for colibacillosis in poultry. APEC remains a constant problem for the poultry industry, despite the use of antimicrobials and disinfectants in farms. The endemicity of APEC in poultry farms is associated with its biofilm-forming ability, which is further aggravated by various virulence factors and resistance to multiple drugs that help bacteria to thrive under different environmental conditions. To characterize APEC from affected broiler chickens and their environments, samples (n=114) from dead birds (heart, liver, lungs, and cloacal swab) and surrounding environments such as feeder, drinker, litter, PVC pipe, water tank wall, feed, and water were collected. The collected samples were subjected to microbial isolation using MacConkey Lactose agar (MLA) and Eosin Methylene Blue agar (EMB), which led to the isolation of 62 E. coli isolates. This was confirmed by uspA gene amplification and Vitek 2 Compact. These isolates were characterized using a set of five virulence genes (hlyF, ompT, iroN, iss, iutA), which yielded 47 (75.80%) isolates as APEC and the remaining as non-APEC. Furthermore, all the 62 isolates were subjected to microtiter plate assay for biofilm detection and the result showed that 36 (58.06%) isolates were able to form moderate to strong biofilms in Trypticase soy broth (TSB) at 72h of incubation. Of the 36 biofilm-producing isolates, 30 were APEC. Biofilm-related genes (crl, csgA, fimH, luxS, and papC) were also detected with higher prevalence among APEC isolates. Antimicrobial susceptibility test using Vitek 2 Compact revealed 43 (91.48%) of 47 APEC isolates as multiple drug resistant (MDR) and 8 (17.02%) as ESBL positive. This study reveals that APEC with biofilm formation ability is present in poultry farms. Further studies are needed to understand the role of biofilms in the pathogenesis and antimicrobial resistance of APEC.}, } @article {pmid35111699, year = {2021}, author = {Sabino, HAC and Valera, FCP and Santos, DV and Fantucci, MZ and Titoneli, CC and Martinez, R and Anselmo-Lima, WT and Tamashiro, E}, title = {Biofilm and Planktonic Antibiotic Resistance in Patients With Acute Exacerbation of Chronic Rhinosinusitis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {813076}, pmid = {35111699}, issn = {2235-2988}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; Microbial Sensitivity Tests ; *Plankton ; Staphylococcus aureus ; }, abstract = {INTRODUCTION: The recalcitrant nature of patients with acute exacerbation of chronic rhinosinusitis (AECRS) potentially involves persisting colonization of the sinonasal mucosa by bacterial biofilms. Biofilms are known to be highly resistant to antibiotics, which may trigger or maintain chronic inflammation in the sinonasal mucosa. However, little is known about the relationship between the minimum inhibitory concentration (MIC) and antibiofilm concentrations of bacteria obtained from AECRS patients.

MATERIAL AND METHODS: Thirty bacterial strains from 25 patients with AECRS were identified and underwent MIC determination (VITEK[®] 2). The planktonic isolates were submitted to an in vitro formation of biofilms (Modified Calgary Biofilm Device) and determination of minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) for amoxicillin, amoxicillin/clavulanic acid, clarithromycin, and levofloxacin. MIC of the planktonic forms was compared with MBIC and MBEC levels, according to the breakpoints established by the Clinical Laboratory Standards Institute guidelines.

RESULTS: The main bacteria retrieved was S. aureus (60%), followed by other Gram-positive and Gram-negative bacteria in lower frequencies. 76.7% of strains formed biofilm in vitro (n=23/30). The planktonic isolates presented high rates of resistance for amoxicillin (82.6%) and clarithromycin (39.1%), and lower rates for amoxicillin/clavulanic acid (17.4%). The biofilm-forming bacteria counterparts presented higher levels of MBIC and MBEC compared to the MIC levels for amoxicillin, amoxicillin/clavulanic acid, and clarithromycin. Levofloxacin was highly effective against both planktonic and biofilm forms. Planktonic resistant forms were associated with levels of antibiofilm concentrations (MBIC and MBEC).

CONCLUSIONS: Biofilm-forming bacteria from AECRS patients are prevalent, and biofilm forms are highly resistant to antibiotics compared to their planktonic counterparts. Antibiotic resistance observed in planktonic forms is a good indicator of biofilm resistance, although near 20% of susceptible planktonic bacteria can produce antibiotic tolerant biofilms.}, } @article {pmid35111695, year = {2021}, author = {Forson, AM and Rosman, CWK and van Kooten, TG and van der Mei, HC and Sjollema, J}, title = {Micrococcal Nuclease stimulates Staphylococcus aureus Biofilm Formation in a Murine Implant Infection Model.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {799845}, pmid = {35111695}, issn = {2235-2988}, mesh = {Animals ; Biofilms ; *Extracellular Traps ; Mice ; Micrococcal Nuclease/genetics ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics ; }, abstract = {Advancements in contemporary medicine have led to an increasing life expectancy which has broadened the application of biomaterial implants. As each implant procedure has an innate risk of infection, the number of biomaterial-associated infections keeps rising. Staphylococcus aureus causes 34% of such infections and is known as a potent biofilm producer. By secreting micrococcal nuclease S. aureus is able to escape neutrophil extracellular traps by cleaving their DNA-backbone. Also, micrococcal nuclease potentially limits biofilm growth and adhesion by cleaving extracellular DNA, an important constituent of biofilms. This study aimed to evaluate the impact of micrococcal nuclease on infection persistence and biofilm formation in a murine biomaterial-associated infection-model with polyvinylidene-fluoride mesh implants inoculated with bioluminescent S. aureus or its isogenic micrococcal nuclease deficient mutant. Supported by results based on in-vivo bioluminescence imaging, ex-vivo colony forming unit counts, and histological analysis it was found that production of micrococcal nuclease enables S. aureus bacteria to evade the immune response around an implant resulting in a persistent infection. As a novel finding, histological analysis provided clear indications that the production of micrococcal nuclease stimulates S. aureus to form biofilms, the presence of which extended neutrophil extracellular trap formation up to 13 days after mesh implantation. Since micrococcal nuclease production appeared vital for the persistence of S. aureus biomaterial-associated infection, targeting its production could be a novel strategy in preventing biomaterial-associated infection.}, } @article {pmid35108083, year = {2022}, author = {Zhong, X and Lu, Z and Wang, F and Yao, N and Shi, M and Yang, M}, title = {Characterization of GefA, a GGEEF Domain-Containing Protein That Modulates Vibrio parahaemolyticus Motility, Biofilm Formation, and Virulence.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {6}, pages = {e0223921}, pmid = {35108083}, issn = {1098-5336}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial ; *Vibrio parahaemolyticus/physiology ; Virulence ; Zebrafish ; }, abstract = {Vibrio parahaemolyticus is a significant foodborne pathogen that causes economic and public health problems worldwide and has a high capacity to adapt to diverse environments and hosts. The second messenger cyclic diguanylate monophosphate (c-di-GMP) allows bacteria to shift from a planktonic form to a communal multicellular lifestyle and plays an important role in bacterial survival and transmission. Here, we characterized single-domain c-di-GMP synthetases in V. parahaemolyticus and identified a novel GGEEF domain-containing protein designated GefA that modulates bacterial swarming motility, biofilm formation, and virulence. GefA inhibits swarming motility by regulating the expression of lateral flagella, while it enhances biofilm formation by controlling exopolysaccharide biosynthesis. Under high-c-di-GMP conditions caused by scrABC knockout, we found that GefA is bifunctional, as it has no effect on swarming motility, but retains the ability to regulate biofilm formation. Subsequent studies suggested that GefA regulates the expression of type III secretion system 1 (T3SS1), which is an important virulence factor in V. parahaemolyticus. Here, we also revealed that the flagella participate in the infection of V. parahaemolyticus. We found that both the T3SS1 and flagella contribute to the GefA-mediated virulence of V. parahaemolyticus in the zebrafish model. Our results expand the knowledge of the V. parahaemolyticus c-di-GMP synthetases and their roles in social behaviors and pathogenicity. IMPORTANCE The c-di-GMP metabolic enzymes constitute one of the largest clusters of potential orthologues in Vibrio parahaemolyticus. However, the specific roles that these individual c-di-GMP metabolic enzymes play are largely unknown. Here, we identified a GGEEF domain-containing protein designated GefA that regulates bacterial behaviors and virulence. We also demonstrated that flagella participate in the infection of this bacterium, through which GefA regulates bacterial virulence. To our knowledge, the roles that c-di-GMP and flagella play in V. parahaemolyticus virulence have never been revealed. Our findings contribute to a better understanding of the function of c-di-GMP and its synthetases in V. parahaemolyticus.}, } @article {pmid35107481, year = {2022}, author = {Hu, H and Kang, X and Shan, Z and Yang, X and Bing, W and Wu, L and Ge, H and Ji, H}, title = {A DNase-mimetic artificial enzyme for the eradication of drug-resistant bacterial biofilm infections.}, journal = {Nanoscale}, volume = {14}, number = {7}, pages = {2676-2685}, doi = {10.1039/d1nr07629a}, pmid = {35107481}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Bacterial Infections/drug therapy ; Biofilms ; DNA, Bacterial ; Deoxyribonucleases/pharmacology ; Humans ; *Pharmaceutical Preparations ; }, abstract = {The construction of multifunctional nano-enzymes is a feasible strategy for fighting multi-drug resistant (MDR) bacterial biofilm-associated infections. Extracellular DNA (eDNA) is an important functional part of biofilm formation, including the initial adherence of bacteria to subsequent development and eventual maturation. A nano-enzyme platform of graphene oxide-based nitrilotriacetic acid-cerium(IV) composite (GO-NTA-Ce) against bacterial biofilm infection has been developed. When located at the site of bacteria-associated infection, GO-NTA-Ce could inhibit the biofilm formation and effectively disperse the formed biofilm by degrading the eDNA. In addition to Ce-mediated deoxyribonuclease (DNase)-like activity, near-infrared laser irradiation of GO-NTA-Ce could produce local hyperthermia to kill the bacteria that lost the protection by the biofilm matrix. In addition, graphene is also a new green broad-spectrum antimicrobial material that can exert its antimicrobial effects through physical damage and chemical damage. In short, our GO-NTA-Ce nano-enzyme platform is capable of effectively eradicating drug-resistant bacterial biofilm infections through the triple action of DNase-like enzyme properties, photothermal therapy, and graphene-based antimicrobial activity, and the nano-composite has excellent potential for the treatment of MDR bacterial biofilm infections.}, } @article {pmid35107361, year = {2022}, author = {Kim, YG and Lee, JH and Park, S and Lee, J}, title = {The Anticancer Agent 3,3'-Diindolylmethane Inhibits Multispecies Biofilm Formation by Acne-Causing Bacteria and Candida albicans.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0205621}, pmid = {35107361}, issn = {2165-0497}, mesh = {Acne Vulgaris/*microbiology ; Anti-Bacterial Agents/pharmacology ; Antineoplastic Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/growth & development ; Humans ; Indoles/*pharmacology ; Microbial Sensitivity Tests ; Phylogeny ; Propionibacteriaceae/drug effects ; Staphylococcus aureus/drug effects ; Virulence ; }, abstract = {The Gram-positive anaerobic bacterium Cutibacterium acnes is a major inhabitant of human skin and has been implicated in acne vulgaris formation and in the formation of multispecies biofilms with other skin-inhabiting organisms like Staphylococcus aureus and Candida albicans. Indoles are widespread in nature (even in human skin) and function as important signaling molecules in diverse prokaryotes and eukaryotes. In the present study, we investigated the antibacterial and antibiofilm activities of 20 indoles against C. acnes. Of the indoles tested, indole-3-carbinol at 0.1 mM significantly inhibited biofilm formation by C. acnes without affecting planktonic cell growth, and the anticancer drug 3,3'-diindolylmethane (DIM) at 0.1 mM (32 μg/mL) also significantly inhibited planktonic cell growth and biofilm formation by C. acnes, whereas the other indoles and indole itself were less effective. Also, DIM at 0.1 mM successfully inhibited multispecies biofilm formation by C. acnes, S. aureus, and C. albicans. Transcriptional analyses showed that DIM inhibited the expressions of several biofilm-related genes in C. acnes, and at 0.05 mM, DIM inhibited hyphal formation and cell aggregation by C. albicans. These results suggest that DIM and other indoles inhibit biofilm formation by C. acnes and have potential use for treating C. acnes associated diseases. IMPORTANCE Since indoles are widespread in nature (even in human skin), we hypothesized that indole and its derivatives might control biofilm formation of acne-causing bacteria (Cutibacterium acnes and Staphylococcus aureus) and fungal Candida albicans. The present study reports for the first time the antibiofilm and antimicrobial activities of several indoles on C. acnes. Of the indoles tested, two anticancer agents, indole-3-carbinol and 3,3'-diindolylmethane found in cruciferous vegetables, significantly inhibited biofilm formation by C. acnes. Furthermore, the most active 3,3'-diindolylmethane successfully inhibited multispecies biofilm formation by C. acnes, S. aureus, and C. albicans. Transcriptional analyses showed that 3,3'-diindolylmethane inhibited the expressions of several biofilm-related genes including lipase, hyaluronate lyase, and virulence-related genes in C. acnes, and 3,3'-diindolylmethane inhibited hyphal formation and cell aggregation by C. albicans. Our findings show that 3,3'-diindolylmethane offers a potential means of controlling acne vulgaris and multispecies biofilm-associated infections due to its antibiofilm and antibiotic properties.}, } @article {pmid35107257, year = {2022}, author = {Green, RM and Bicker, KL}, title = {Development of an Anti-Biofilm Screening Technique Leads to the Discovery of a Peptoid with Efficacy against Candida albicans.}, journal = {ACS infectious diseases}, volume = {8}, number = {2}, pages = {310-320}, pmid = {35107257}, issn = {2373-8227}, support = {R03 AI146393/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Biofilms ; Candida ; Candida albicans ; Mammals ; *Peptoids/pharmacology ; }, abstract = {Bacteria and fungi can secrete and reside within a complex polysaccharide matrix, forming a biofilm that protects these pathogens from the immune response and conventional antibiotics. Because many microbial pathogens grow within biofilms in clinical settings, there is a need for antimicrobial agents effective against biofilm-protected infections. We report the adaptation of a phenotypic high-throughput assay for discovering antimicrobial peptoids toward the screening of combinatorial libraries against established biofilms. This method, termed the Inverted Peptoid Library Agar Diffusion (iPLAD) assay, required optimization of growth media, reducing reagent, and fungal viability reporter. Once optimized, iPLAD was used to screen a combinatorial peptoid library against Candida albicans, a biofilm-forming fungal pathogen responsible for most hospital-acquired infections. This screening resulted in a lipopeptoid termed RMG9-11 with excellent activity against several species of Candida, including drug-resistant strains of C. albicans and the emerging and dangerous C. auris. Additionally, the cytotoxicity of RMG9-11 against several mammalian cell lines was minimal. This work provides a new method for the identification of compounds effective against biofilm-protected pathogens and demonstrates its utility by identifying a promising anti-Candida peptoid.}, } @article {pmid35106661, year = {2022}, author = {Azami, S and Arefian, E and Kashef, N}, title = {Postbiotics of Lactobacillus casei target virulence and biofilm formation of Pseudomonas aeruginosa by modulating quorum sensing.}, journal = {Archives of microbiology}, volume = {204}, number = {2}, pages = {157}, pmid = {35106661}, issn = {1432-072X}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms ; *Lacticaseibacillus casei/genetics ; Mice ; Pseudomonas aeruginosa/genetics ; *Quorum Sensing ; Virulence ; Virulence Factors ; }, abstract = {Among various anti-virulence aspects, the efficacy of the bioactive constituents of probiotics, referred to as postbiotics, to affect quorum sensing (QS)-modulated signaling of pathogens, is considered as a safe natural approach. The present study investigated the potential QS-inhibitory activity of lyophilized postbiotics from Lactobacillus casei sub sp. casei PTCC 1608 on virulence phenotypes and biofilm of two strains and three clinical isolates of Pseudomonas aeruginosa. The effect of L. casei postbiotics (LCP) at sub-minimum inhibitory concentration on the expression of QS genes including lasR/I, rhlR/I, pqsA, pqsR and virulence genes including pelF (pellicle/biofilm glycosyltransferase PelF), lasB (elastase LasB) and toxA (exotoxin A) was evaluated. The viability of mouse fibroblastic NIH/3T3 cell line treated with sub-MICS of LCP was also investigated. Postbiotics were characterized using mass spectrometry-based analyses. The QS-attenuation effect of pure lactic acid as the major constituent of LCP was determined on P. aeruginosa strains. Neutralized postbiotics and crude bacteriocin did not exhibit any antibacterial activity. It was found that sub-MICS of LCP could more drastically attenuate the tested virulence phenotypes and biofilm formation than lactic acid. Biofilm inhibition was confirmed using scanning electron microscopy. The rhlI, rhlR, and pelF genes were down-regulated after treatment with LCP. No cytotoxicity effect was observed on NIH/3T3 cell line. The findings demonstrated that postbiotics of L. casei could reduce the virulence and biofilm development of P. aeruginosa and suggested a novel safe natural source for the expansion of anti-virulence treatments.}, } @article {pmid35105823, year = {2022}, author = {Singh, A and Amod, A and Pandey, P and Bose, P and Pingali, MS and Shivalkar, S and Varadwaj, PK and Sahoo, AK and Samanta, SK}, title = {Bacterial biofilm infections, their resistance to antibiotics therapy and current treatment strategies.}, journal = {Biomedical materials (Bristol, England)}, volume = {17}, number = {2}, pages = {}, doi = {10.1088/1748-605X/ac50f6}, pmid = {35105823}, issn = {1748-605X}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria ; *Bacterial Infections/drug therapy/microbiology ; *Biofilms ; Drug Resistance, Microbial ; Humans ; }, abstract = {Nearly 80% of human chronic infections are caused due to bacterial biofilm formation. This is the most leading cause for failure of medical implants resulting in high morbidity and mortality. In addition, biofilms are also known to cause serious problems in food industry. Biofilm impart enhanced antibiotic resistance and become recalcitrant to host immune responses leading to persistent and recurrent infections. It makes the clinical treatment for biofilm infections very difficult. Reduced penetration of antibiotic molecules through EPS, mutation of the target site, accumulation of antibiotic degrading enzymes, enhanced expression of efflux pump genes are the probable causes for antibiotics resistance. Accordingly, strategies like administration of topical antibiotics and combined therapy of antibiotics with antimicrobial peptides are considered for alternate options to overcome the antibiotics resistance. A number of other remediation strategies for both biofilm inhibition and dispersion of established biofilm have been developed. The metallic nanoparticles (NPs) and their oxides have recently gained a tremendous thrust as antibiofilm therapy for their unique features. This present comprehensive review gives the understanding of antibiotic resistance mechanisms of biofilm and provides an overview of various currently available biofilm remediation strategies, focusing primarily on the applications of metallic NPs and their oxides.}, } @article {pmid35104274, year = {2021}, author = {Camacho-Ortiz, A and Lara-Medrano, R and Martínez-Reséndez, MF and Mendoza-Olazarán, S and Flores-Treviño, S and Garza-González, E}, title = {Azithromycin effect on multidrug resistant Acinetobacter baumannii biofilm production and composition.}, journal = {Gaceta medica de Mexico}, volume = {157}, number = {5}, pages = {478-483}, doi = {10.24875/GMM.M21000602}, pmid = {35104274}, issn = {0016-3813}, mesh = {*Acinetobacter Infections/drug therapy ; *Acinetobacter baumannii/genetics ; Azithromycin/pharmacology ; Biofilms ; Carbapenems ; Humans ; }, abstract = {OBJECTIVES: To evaluate the effect of azithromycin (AZM) on biofilm formation and composition in multidrug resistant (MDR) Acinetobacter baumannii.

MATERIAL AND METHODS: Ninety-six A. baumannii isolates were studied. Antimicrobial susceptibility and sub-minimum inhibitory concentration (sub-MIC) were determined by the broth microdilution method. Carbapenemase genes were detected by polymerase chain reaction and clonal diversity by pulsed-field gel electrophoresis (PFGE). Biofilm formation without AZM and AZM sub-MIC were determined by crystal violet staining. AZM-free biofilm composition and AZM sub-MIC were determined by detachment assays.

RESULTS: The selected A. baumannii were MDR; 93.8% were carbapenem-resistant and 24 were OXA-24-positive. PFGE showed predominance of clones A (53%), B (34.7%) and C (12.5%). Biofilm production at AZM sub-MICs decreased in 53.1%, increased in 34.7% and showed no differences in 12.5% of isolates, in comparison with biofilm production without AZM.

CONCLUSION: AZM sub-MIC can reduce biofilm production in A. baumannii MDR isolates with decreased protein and DNA in the biofilm. Our results may be useful in synergy studies for new therapeutic alternatives.}, } @article {pmid35101567, year = {2022}, author = {Liu, X and Cao, B and Yang, L and Gu, JD}, title = {Biofilm control by interfering with c-di-GMP metabolism and signaling.}, journal = {Biotechnology advances}, volume = {56}, number = {}, pages = {107915}, doi = {10.1016/j.biotechadv.2022.107915}, pmid = {35101567}, issn = {1873-1899}, mesh = {*Bacterial Proteins/genetics ; Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; *Gene Expression Regulation, Bacterial ; }, abstract = {Biofilm formation and biofilm-induced biodeterioration of surfaces have deeply affected the life of our community. Cyclic dimeric guanosine monophosphate (c-di-GMP) is a small nucleotide-based signaling molecule in bacteria, which functions as a second messenger mediating a wide range of bacterial processes, such as cell motility, biofilm formation, virulence expression, and cell cycle progression. C-di-GMP regulated phenotypes are triggered by a variety of determinants, such as metabolic cues and stress factors that affect c-di-GMP synthesis, the transduction and conducting of signals by specific effectors, and their actions on terminal targets. Therefore, understanding of the regulatory mechanisms of c-di-GMP would greatly benefit the control of the relevant bacterial processes, particularly for the development of anti-biofilm technologies. Here, we discuss the regulatory determinants of c-di-GMP signaling, identify the corresponding chemical inhibitors as anti-biofilm agents, and shed light on further perspectives in the metabolic regulation of c-di-GMP through chemical and biological approaches. This review will advance the development of anti-biofilm policies applied in the industries of medicine, environment and engineering.}, } @article {pmid35101486, year = {2022}, author = {Li, P and Wang, C and Liu, G and Luo, X and Rauan, A and Zhang, C and Li, T and Yu, H and Dong, S and Gao, Q}, title = {A hydroponic plants and biofilm combined treatment system efficiently purified wastewater from cold flowing water aquaculture.}, journal = {The Science of the total environment}, volume = {821}, number = {}, pages = {153534}, doi = {10.1016/j.scitotenv.2022.153534}, pmid = {35101486}, issn = {1879-1026}, mesh = {Aquaculture ; Biofilms ; Bioreactors ; *Denitrification ; Hydroponics ; Nitrogen/analysis ; *Wastewater/analysis ; }, abstract = {Recently, more and more cold flowing water aquaculture has been adopted, but its wastewater treatment is always ignored, which causes great pressure on the environment. In this study, a compound in-situ treatment system that applied hydroponic plants and biofilm was constructed to treat the wastewater produced by cold flowing water culture of sturgeon. The removal efficiency of the nutrients from culture and the microbial composition in water and biofilm were tested, the correlation between the water quality indexes and bacterium was analyzed, and the abundance of nitrogen and phosphorus cycling genes was quantified. The results show that the system respectively achieved 90%, 100%, 100%, 100% and 48% removal efficiency of NH4[+]-N, NO3[-]-N, TN, TP and COD which were produced by experimental sturgeon culture. Chinese cabbage (Brassica rapa var. chinensis) and water dropwort (Oenanthe javanica) showed obvious growth in the four plants, which contributed to the removal of nutrients from wastewater. Besides, in the biofilm, Proteobacteria, Bacteroidetes and Verrucomicrobia became the top three dominant flora at the phylum level, and Flavobacterium, Rhodoferax, Sphaerotilus and Chitinimonas became the top four dominant flora at the genus level, which promoted the removal of nitrogen in the wastewater. The FAPROTAX analysis result shows that the highest functions within the carbon and nitrogen metabolisms were significantly identified in the biofilm, such as chemoheterotrophy, aerobic chemoheterotrophy and nitrate reduction. Further, the abundance of denitrifying genes (narG and napA) was higher than the nitrifying related genes (nxrB and amoA), indicating the more active denitrifying process. In summary, the compound in-situ treatment system efficiently removed nutrients from cold flowing water aquaculture. And the combined purification of hydroponic plants and biofilm which is rich in denitrifying bacterium plays an essential role in this process.}, } @article {pmid35100443, year = {2022}, author = {Zhang, L and Shahin, K and Soleimani-Delfan, A and Ding, H and Wang, H and Sun, L and Wang, R}, title = {Phage JS02, a putative temperate phage, a novel biofilm-degrading agent for Staphylococcus aureus.}, journal = {Letters in applied microbiology}, volume = {75}, number = {3}, pages = {643-654}, doi = {10.1111/lam.13663}, pmid = {35100443}, issn = {1472-765X}, support = {31602078//National Natural Science Foundation of China/ ; 31802221//National Natural Science Foundation of China/ ; 31950410562//National Natural Science Foundation of China/ ; BK20180054//National Natural Science Foundation of Jiangsu Province/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Ceftazidime ; Genome, Viral ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Plankton ; *Siphoviridae ; *Staphylococcal Infections/genetics ; Staphylococcus Phages/genetics ; Staphylococcus aureus ; Wastewater ; }, abstract = {Staphylococcus aureus is a biofilm-producing organism that is frequently isolated from various environments worldwide. Because of the natural resistance of S. aureus biofilm to antibiotics, bacteriophages are considered as a promising alternative for its removal. The bacteriophage vB_SauS_JS02 was isolated from livestock wastewater and showed activity against multidrug-resistant S. aureus. The phage vB_SauS_JS02 exhibited a broad host range and possessed a large burst size (52 PFU/CFU) as well as moderate pH stability (4-11) and appropriate thermal tolerance (40-50°C). Electron microscopy and genome sequence revealed that vB_SauS_JS02 belonged to Triavirus genus in Siphoviridae family. Genetic analysis of the 46 kb sequence of vB_SauS_JS02 revealed 66 ORFs. The predicted protein products of the ORFs were clustered functionally into five groups as follows: replication/regulation, DNA packaging, structure/morphogenesis, lysis and lysogeny. Although the phage vB_SauS_JS02 was a temperate phage, it exhibited a higher inhibiting and degrading activity against planktonic cells (80~90% reduction), even to S. aureus biofilm (~68% reduction in biofilm formation). Moreover, the removal activity of the phage vB_SauS_JS02 against both planktonic cells and S. aureus biofilms was even better than that of the antibiotic (ceftazidime). In summary, the present study introduced the phage vB_SauS_JS02 as a potential biocontrol agent against biofilm-producing S. aureus after making it virulent. It may be applicable for phage therapy.}, } @article {pmid35100165, year = {2022}, author = {Divyashree, M and Mani, MK and Karunasagar, I}, title = {Association of exopolysaccharide genes in biofilm developing antibiotic-resistant Pseudomonas aeruginosa from hospital wastewater.}, journal = {Journal of water and health}, volume = {20}, number = {1}, pages = {176-184}, doi = {10.2166/wh.2021.223}, pmid = {35100165}, issn = {1477-8920}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Hospitals ; *Pseudomonas aeruginosa/genetics ; Wastewater ; }, abstract = {The study aimed to examine the relationship between antibiotic resistance, biofilm formation and genes responsible for biofilm formation. Sixty-six Pseudomonas aeruginosa isolates were obtained from hospital wastewater and analyzed for their antibiotic resistance. Biofilm production among the isolates was tested by indirect quantification method crystal violet assay. Biofilm-associated genes among these isolates psl, alg, and pel were also checked. The maximum resistance was observed for ampicillins (88.24%) followed by nalidixic (83.82%), and nitrofurantoin (64.71%), respectively. Biofilm phenotypes are distributed in the following categories: high 39.39% (n = 26); moderate 57.57% (n = 38), and weak 3.0% (n = 2). Among the total isolates, biofilm-associated genes were detected in 84.84% (n = 56) of isolates and the remaining isolates 15.15% (n = 10) did not harbor any genes. In this study, pslB was the most predominant gene observed (71.21%, n = 47) followed by pslA (57.57%, n = 38), pelA (45.45%, n = 30), algD (43.93%, n = 29), and pelD (27.27%, n = 18), respectively. The present study reveals that the majority of the isolates are multidrug resistant being moderate and high biofilm formers. The study implies that biofilm acts as a machinery for bacteria to survive in the hospital effluent which is an antibiotic stress environment.}, } @article {pmid35100043, year = {2022}, author = {Zhang, J and Dong, F and Liu, S and Zhang, D and Wang, X}, title = {Biofilm streamer growth dynamics in various microfluidic channels.}, journal = {Canadian journal of microbiology}, volume = {68}, number = {5}, pages = {367-375}, doi = {10.1139/cjm-2021-0346}, pmid = {35100043}, issn = {1480-3275}, mesh = {Bacillus subtilis ; Bacteria ; *Biofilms ; *Microfluidics ; }, abstract = {Biofilms are microbial colonies that are encapsulated in extracellular polymers secreted by cells through their proliferation and differentiation. Biofilms exist on solid surfaces, liquid surfaces, or in liquid media, where the growth of the bacterial biofilm is closely related to the velocity of the secondary flow, main flow, and geometry of the channel, which are difficult to measure in a natural fluid environment, making the study of the biofilm streamer growth process difficult. In this study, we used microfluidic channels made of polydimethylsiloxane to study the growth dynamics of Bacillus subtilis biofilm streamers. We observed that the biofilm streamer growth undergoes three stages with different growth characteristics. First, we found that the initial growth of the streamer is located at the position with the maximum value of P = secondary flow velocity × main flow velocity. Second, the biofilm underwent floating growth around the microcolumn obstacle. After the transition stage, the last growth stage includes two types because of the different attachment strengths and mechanical properties of the biofilm. Our research provides new insights into the formation and shedding of biofilm streamers in natural and industrial environments and helps us to better understand biofilm growth in fluid flow.}, } @article {pmid35099707, year = {2022}, author = {Taghizadeh, SM and Ebrahiminezhad, A and Raee, MJ and Ramezani, H and Berenjian, A and Ghasemi, Y}, title = {A Study of L-Lysine-Stabilized Iron Oxide Nanoparticles (IONPs) on Microalgae Biofilm Formation of Chlorella vulgaris.}, journal = {Molecular biotechnology}, volume = {64}, number = {6}, pages = {702-710}, pmid = {35099707}, issn = {1559-0305}, mesh = {Biofilms ; *Chlorella vulgaris ; Lysine ; Magnetic Iron Oxide Nanoparticles ; *Microalgae ; *Nanoparticles/chemistry ; }, abstract = {Despite iron-based nanoparticles gaining huge attraction in various field of sciences and technology, their application rises ecological concerns due to lack of studies on their interaction with microbial cells populations and communities, such as biofilms. In this study, Chlorella vulgaris cells were employed as a model of aquatic microalgae to investigate the impacts of L-lysine-coated iron oxide nanoparticles (lys@IONPs) on microalgal growth and biofilm formation. In this regard, C. vulgaris cells were exposed to different concentrations of lys@IONPs and the growth of cells was evaluated by OD600 and biofilm formation was analyzed using crystal violet staining throughout 12 days. It was revealed that low concentration of nanoparticles (< 400 µg/mL) can promote cell growth and biofilm formation. However, higher concentrations have an adverse effect on microalgal communities. It is interesting that microalgal growth and biofilm are concentration- and exposure time-dependent to lys@IONPs. Over long period (~ 12 days) exposure to high concentrations of nanoparticles, cells can adapt with the condition, so growth was raised and biofilm started to develop. Results of the present study could be considered in ecological issues and also bioprocesses using microalgal cells.}, } @article {pmid35099174, year = {2022}, author = {Wang, J and Jiang, Z and Wei, Y and Wang, W and Wang, F and Yang, Y and Song, H and Yuan, Q}, title = {Multiplexed Identification of Bacterial Biofilm Infections Based on Machine-Learning-Aided Lanthanide Encoding.}, journal = {ACS nano}, volume = {16}, number = {2}, pages = {3300-3310}, doi = {10.1021/acsnano.1c11333}, pmid = {35099174}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/chemistry ; *Bacterial Infections ; Biofilms ; Humans ; *Lanthanoid Series Elements ; Machine Learning ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; }, abstract = {Pathogenic biofilms are up to 1000-fold more drug-resistant than planktonic pathogens and cause about 80% of all chronic infections worldwide. The lack of prompt and reliable biofilm identification methods seriously prohibits the diagnosis and treatment of biofilm infections. Here, we developed a machine-learning-aided cocktail assay for prompt and reliable biofilm detection. Lanthanide nanoparticles with different emissions, surface charges, and hydrophilicity are formulated into the cocktail kits. The lanthanide nanoparticles in the cocktail kits can offer competitive interactions with the biofilm and further maximize the charge and hydrophilicity differences between biofilms. The physicochemical heterogeneities of biofilms were transformed into luminescence intensity at different wavelengths by the cocktail kits. The luminescence signals were used as learning data to train the random forest algorithm, and the algorithm could identify the unknown biofilms within minutes after training. Electrostatic attractions and hydrophobic-hydrophobic interactions were demonstrated to dominate the binding of the cocktail kits to the biofilms. By rationally designing the charge and hydrophilicity of the cocktail kit, unknown biofilms of pathogenic clinical isolates were identified with an overall accuracy of over 80% based on the random forest algorithm. Moreover, the antibiotic-loaded cocktail nanoprobes efficiently eradicated biofilms since the nanoprobes could penetrate deep into the biofilms. This work can serve as a reliable technique for the diagnosis of biofilm infections and it can also provide instructions for the design of multiplex assays for detecting biochemical compounds beyond biofilms.}, } @article {pmid35098894, year = {2023}, author = {Verma, N and Srivastava, S and Malik, R and Goyal, P and Pandey, J}, title = {Inhibition and disintegration of Bacillus subtilis biofilm with small molecule inhibitors identified through virtual screening for targeting TasA(28-261), the major protein component of ECM.}, journal = {Journal of biomolecular structure & dynamics}, volume = {41}, number = {6}, pages = {2431-2447}, doi = {10.1080/07391102.2022.2033135}, pmid = {35098894}, issn = {1538-0254}, mesh = {Humans ; *Bacillus subtilis/physiology ; Molecular Docking Simulation ; *Biofilms ; Lovastatin/metabolism ; Simvastatin ; Bacterial Proteins/metabolism ; }, abstract = {Microbial biofilms have been recognized for a vital role in antibiotic resistance and chronic microbial infections for 2-3 decades; still, there are no 'anti-biofilm drugs' available for human applications. There is an urgent need to develop novel 'anti-biofilms' therapeutics to manage biofilm-associated infectious diseases. Several reports have suggested that targeting molecules involved in quorum sensing or biofilm-specific transcription may inhibit biofilm formation. However, the possibility of targeting other vital components of microbial biofilms, especially the extracellular matrix (ECM) components, has remained largely unexplored. Here we report targeting TasA(28-261), the major proteinaceous component of Bacillus subtilis ECM with two small molecule inhibitors (lovastatin and simvastatin) identified through virtual screening and drug repurposing, resulted in complete inhibition of biofilm. In molecular docking and dynamics simulation studies, lovastatin was observed to make stable interactions with TasA(28-261), whereas the simvastatin - TasA(28-261) interactions were relatively less stable. However, in subsequent in vitro studies, both lovastatin and simvastatin successfully inhibited B. subtilis biofilm formation at MIC values of < 10 µg/ml. Besides, these potential inhibitors also caused the disintegration of pre-formed biofilms. Results presented here provide 'proof of concept' for the hypothesis that targeting the extracellular matrix's vital component(s) could be one of the most efficient approaches for inhibiting microbial biofilms and disintegrating the pre-formed biofilms. We propose that a similar approach targeting ECM-associated proteins with FDA-approved drugs could be implemented to develop novel anti-biofilm therapeutic strategies against biofilm-forming chronic microbial pathogens.Communicated by Ramaswamy H. Sarma.}, } @article {pmid35098100, year = {2022}, author = {Zheng, J and Shang, Y and Wu, Y and Zhao, Y and Chen, Z and Lin, Z and Li, P and Sun, X and Xu, G and Wen, Z and Chen, J and Wang, Y and Wang, Z and Xiong, Y and Deng, Q and Qu, D and Yu, Z}, title = {Loratadine inhibits Staphylococcus aureus virulence and biofilm formation.}, journal = {iScience}, volume = {25}, number = {2}, pages = {103731}, pmid = {35098100}, issn = {2589-0042}, abstract = {There are no anti-virulence and anti-biofilm treatments for Staphylococcus aureus infection. We found that 25 μM loratadine inhibits S. aureus biofilm formation under static or flow-based conditions. Testing of loratadine effects on 255 clinical S. aureus strains with varying biofilm robustness showed inhibition of biofilm formation in medium and strong, but not weak, biofilm-producing strains. At 25 μM, loratadine reduced pigmentation and hemolysis of the bacteria without affecting growth. Loratadine (5 mg/kg) reduced mortality in S. aureus pulmonary infection model mice and acted synergistically with vancomycin to reduce pulmonary bacterial load and levels of inflammatory cytokines in bronchoalveolar lavage fluid. Loratadine analogues (side-chain carbamate moiety changed) inhibited biofilm formation, pigmentation, and hemolysis of S. aureus. Regarding mechanism, loratadine exposure reduced RNA levels of virulence-related S. aureus genes, and loratadine-induced mutations in MgrA reduced loratadine-MgrA binding. Overexpression of mutated mgrA in wild-type S. aureus decreased the biofilm formation inhibition effect of loratadine.}, } @article {pmid35097137, year = {2021}, author = {Dolatshah, L and Tabatabaei, M}, title = {A phenotypic and molecular investigation of biofilm formation in clinical samples of Pseudomonas aeruginosa.}, journal = {Molecular biology research communications}, volume = {10}, number = {4}, pages = {157-163}, pmid = {35097137}, issn = {2345-2005}, abstract = {Pseudomonas aeruginosa is identified as a versatile opportunistic microorganism with metabolic diversity contributing to a wide range of health burdens, especially in immunocompromised patients. This bacterium is the cause of 10 to 20% of nosocomial infections. In this study, we evaluated the phenotypic characterizations of biofilm formation in P. aeruginosa clinical isolates using micro-titer plate assay. Indeed, we estimated the prevalence of QS (rhlI, rhlR, rhlAB, lasB, lasI, lasR, aprA) and virulence genes (pslA and cupA) by PCR. The results showed that among 69% of the isolates forming biofilm, 9% were strong biofilm producers, whereas 13% and 47% of isolates produced moderate and low amounts of biofilm, respectively. All isolates possessed cupA and seven QS genes (rhlI, rhlR, rhlAB, lasB, lasI, lasR, aprA), while 92% of the isolates possessed the pslA gene. Identification of these genes and their association with biofilm formation can be advantageous in adopting therapeutic methods.}, } @article {pmid35096655, year = {2021}, author = {Mlynek, KD and Lopez, CT and Fetterer, DP and Williams, JA and Bozue, JA}, title = {Phase Variation of LPS and Capsule Is Responsible for Stochastic Biofilm Formation in Francisella tularensis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {808550}, pmid = {35096655}, issn = {2235-2988}, mesh = {Biofilms ; *Francisella ; *Francisella tularensis ; Humans ; Lipopolysaccharides ; Phase Variation ; *Tularemia/microbiology ; }, abstract = {Biofilms have been established as an important lifestyle for bacteria in nature as these structured communities often enable survivability and persistence in a multitude of environments. Francisella tularensis is a facultative intracellular Gram-negative bacterium found throughout much of the northern hemisphere. However, biofilm formation remains understudied and poorly understood in F. tularensis as non-substantial biofilms are typically observed in vitro by the clinically relevant subspecies F. tularensis subsp. tularensis and F. tularensis subsp. holarctica (Type A and B, respectively). Herein, we report conditions under which robust biofilm development was observed in a stochastic, but reproducible manner in Type A and B isolates. The frequency at which biofilm was observed increased temporally and appeared switch-like as progeny from the initial biofilm quickly formed biofilm in a predictable manner regardless of time or propagation with fresh media. The Type B isolates used for this study were found to more readily switch on biofilm formation than Type A isolates. Additionally, pH was found to function as an environmental checkpoint for biofilm initiation independently of the heritable cellular switch. Multiple colony morphologies were observed in biofilm positive cultures leading to the identification of a particular subset of grey variants that constitutively produce biofilm. Further, we found that constitutive biofilm forming isolates delay the onset of a viable non-culturable state. In this study, we demonstrate that a robust biofilm can be developed by clinically relevant F. tularensis isolates, provide a mechanism for biofilm initiation and examine the potential role of biofilm formation.}, } @article {pmid35095970, year = {2021}, author = {Nazari, M and Bickel, S and Benard, P and Mason-Jones, K and Carminati, A and Dippold, MA}, title = {Biogels in Soils: Plant Mucilage as a Biofilm Matrix That Shapes the Rhizosphere Microbial Habitat.}, journal = {Frontiers in plant science}, volume = {12}, number = {}, pages = {798992}, pmid = {35095970}, issn = {1664-462X}, abstract = {Mucilage is a gelatinous high-molecular-weight substance produced by almost all plants, serving numerous functions for plant and soil. To date, research has mainly focused on hydraulic and physical functions of mucilage in the rhizosphere. Studies on the relevance of mucilage as a microbial habitat are scarce. Extracellular polymeric substances (EPS) are similarly gelatinous high-molecular-weight substances produced by microorganisms. EPS support the establishment of microbial assemblages in soils, mainly through providing a moist environment, a protective barrier, and serving as carbon and nutrient sources. We propose that mucilage shares physical and chemical properties with EPS, functioning similarly as a biofilm matrix covering a large extent of the rhizosphere. Our analyses found no evidence of consistent differences in viscosity and surface tension between EPS and mucilage, these being important physical properties. With regard to chemical composition, polysaccharide, protein, neutral monosaccharide, and uronic acid composition also showed no consistent differences between these biogels. Our analyses and literature review suggest that all major functions known for EPS and required for biofilm formation are also provided by mucilage, offering a protected habitat optimized for nutrient mobilization. Mucilage enables high rhizo-microbial abundance and activity by functioning as carbon and nutrient source. We suggest that the role of mucilage as a biofilm matrix has been underestimated, and should be considered in conceptual models of the rhizosphere.}, } @article {pmid35095817, year = {2021}, author = {Li, S and Chan, KK and Hua, MZ and Gölz, G and Lu, X}, title = {Inhibition of AI-2 Quorum Sensing and Biofilm Formation in Campylobacter jejuni by Decanoic and Lauric Acids.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {811506}, pmid = {35095817}, issn = {1664-302X}, abstract = {Campylobacter jejuni is a major bacterial cause of human diarrheal diseases worldwide. Despite its sensitivity to environmental stresses, C. jejuni ubiquitously distributes throughout poultry production chains. Biofilm formation mediated by quorum sensing is suggested to be critical to the survival of C. jejuni in agroecosystem. C. jejuni possesses LuxS, the enzyme involved in the production of autoinducer-2 (AI-2) signaling molecules. In this study, two fatty acids, namely decanoic acid and lauric acid, were identified to be effective in inhibiting AI-2 activity of C. jejuni. Both decanoic acid and lauric acid at 100 ppm inhibited ∼90% AI-2 activity (P < 0.05) of C. jejuni without bacterial inactivation. The biofilm biomass of two C. jejuni strains was reduced by 10-50% (P < 0.05) after treatment by both fatty acids, while increased biofilm formation was observed for one C. jejuni strain. In addition, both fatty acids effectively reduced the motility of all tested C. jejuni strains. These findings can aid in developing alternative C. jejuni control strategies in agri-food and clinical settings.}, } @article {pmid35095797, year = {2021}, author = {Robin, B and Nicol, M and Le, H and Tahrioui, A and Schaumann, A and Vuillemenot, JB and Vergoz, D and Lesouhaitier, O and Jouenne, T and Hardouin, J and Potron, A and Perrot, V and Dé, E}, title = {MacAB-TolC Contributes to the Development of Acinetobacter baumannii Biofilm at the Solid-Liquid Interface.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {785161}, pmid = {35095797}, issn = {1664-302X}, abstract = {Acinetobacter baumannii has emerged as one of the most problematic bacterial pathogens responsible for hospital-acquired and community infections worldwide. Besides its high capacity to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development. This lifestyle confers additional protection against various treatments and allows it to persist for long periods in various hospital niches. Due to their remarkable antimicrobial tolerance, A. baumannii biofilms are difficult to control and ultimately eradicate. Further insights into the mechanism of biofilm development will help to overcome this challenge and to develop novel antibiofilm strategies. To unravel critical determinants of this sessile lifestyle, the proteomic profiles of two A. baumannii strains (ATTC17978 and SDF) grown in planktonic stationary phase or in mature solid-liquid (S-L) biofilm were compared using a semiquantitative proteomic study. Of interest, among the 69 common proteins determinants accumulated in the two strains at the S-L interface, we sorted out the MacAB-TolC system. This tripartite efflux pump played a role in A. baumannii biofilm formation as demonstrated by using ΔmacAB-tolC deletion mutant. Complementary approaches allowed us to get an overview of the impact of macAB-tolC deletion in A. baumannii physiology. Indeed, this efflux pump appeared to be involved in the envelope stress response occurring in mature biofilm. It contributes to maintain wild type (WT) membrane rigidity and provides tolerance to high osmolarity conditions. In addition, this system is probably involved in the maintenance of iron and sulfur homeostasis. MacAB-TolC might help this pathogen face and adapt to deleterious conditions occurring in mature biofilms. Increasing our knowledge of A. baumannii biofilm formation will undoubtedly help us develop new therapeutic strategies to tackle this emerging threat to human health.}, } @article {pmid35093618, year = {2022}, author = {Xu, L and Guan, F and Ma, Y and Zhang, R and Zhang, Y and Zhai, X and Dong, X and Wang, Y and Duan, J and Hou, B}, title = {Inadequate dosing of THPS treatment increases microbially influenced corrosion of pipeline steel by inducing biofilm growth of Desulfovibrio hontreensis SY-21.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {145}, number = {}, pages = {108048}, doi = {10.1016/j.bioelechem.2021.108048}, pmid = {35093618}, issn = {1878-562X}, mesh = {Biofilms ; Corrosion ; *Desulfovibrio ; *Disinfectants/pharmacology ; Flavonoids ; Steel/chemistry ; }, abstract = {Biocides are often used to mitigate the microbially influenced corrosion (MIC) of construction materials in many fields. To study the effect of inadequate dosing of non-oxidizing biocide tetrakis (hydroxymethyl) phosphonium sulfate (THPS) on corrosion of pipeline steel caused by microorganisms, a novel marine isolate Desulfovibrio hontreensis SY-21 was selected as a test microorganism. Weight loss rate determination, morphological analyses, and corrosion product analyses combined with electrochemical measurements were performed to investigate the influence of THPS on the MIC of X70 pipeline steel. The responses of sessile and planktonic cells of D. hontreensis to THPS were also studied. Results showed that D. hontreensis cells could significantly promote steel corrosion and induce local corrosion pits. With a THPS addition within the tolerance range of D. hontreensis for the biocide, MIC of the steel was further promoted by 65%. The growth of planktonic cells was inhibited by the biocide, but the number of biofilm cells was significantly increased. This study revealed that THPS concentrations within a specific range increased the corrosive effect of the presence of D. hontreensis by promoting the growth of sessile cells and biofilm formation. Therefore, the use of the biocide in practical applications needs to be properly considered and managed.}, } @article {pmid35093525, year = {2022}, author = {Pan, D and Shao, S and Zhong, J and Wang, M and Wu, X}, title = {Performance and mechanism of simultaneous nitrification-denitrification and denitrifying phosphorus removal in long-term moving bed biofilm reactor (MBBR).}, journal = {Bioresource technology}, volume = {348}, number = {}, pages = {126726}, doi = {10.1016/j.biortech.2022.126726}, pmid = {35093525}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Nitrification ; Nitrogen/analysis ; *Phosphorus ; Sewage ; Waste Disposal, Fluid ; Wastewater/analysis ; }, abstract = {The long-term moving bed biofilm reactor (MBBR) with carrier-attached biofilm was successfully operated for simultaneous removal of nitrogen, phosphorus, and COD at various C/N ratios. Results indicated that 99.60%, 63.58%, 78.94%, and 59.64% of NH4[+]-N, NO3[-]-N, TN, and TP were removed at C/N ratio, hydraulic retention time (HRT), and carrier film amount of 5, 40 h, and 1.2 mg·g[-1]. Nitrogen balance analysis showed that more than 89% of nitrogen (C/N = 20, 15, 10, 5) was converted to gas products. Extracellular polymeric substances (EPS), electron transport system activity (ETSA), and enzyme activity of biofilm were evaluated. Protein (PN)/polysaccharose (PS) values and ETSA decreased with the decrease of C/N ratios. Metagenomics sequencing further revealed that the prominent phyla for nitrogen and phosphorus removal were identified including Proteobacteria, Acidobacteria, Nitrospirae, and Chloroflexi. Proteobacteriaand Gammaproteobacteria were identified as the dominant denitrifying phosphate accumulating organisms (PAO) at the phylum and class level, respectively.}, } @article {pmid35093368, year = {2022}, author = {Qi, Z and Huang, Z and Liu, C}, title = {Metabolism differences of biofilm and planktonic Pseudomonas aeruginosa in viable but nonculturable state induced by chlorine stress.}, journal = {The Science of the total environment}, volume = {821}, number = {}, pages = {153374}, doi = {10.1016/j.scitotenv.2022.153374}, pmid = {35093368}, issn = {1879-1026}, mesh = {Biofilms ; *Chlorine/pharmacology ; Plankton ; *Pseudomonas aeruginosa ; Tandem Mass Spectrometry ; }, abstract = {More than 95% of the bacteria in environment are viable but nonculturable (VBNC). However, it is difficult to elucidate directly the metabolic characteristics of these VBNC bacteria and the differences between biofilm-VBNC bacteria and planktonic-VBNC bacteria. In this study, VBNC P. aeruginosa induced by chlorine was used to clarify the metabolism characteristics and mechanism of differential metabolism between biofilm-VBNC bacteria and planktonic-VBNC bacteria. Results showed that P. aeruginosa in biofilm state was more likely to enter VBNC state. The mechanisms of differential metabolism were involved in the difference of reactive oxygen species production owing to the protection of extracellular polymers. [15]N and [2]H labeled single-cell Raman spectra directly proved that VBNC state bacteria still maintained low material and energy metabolism, and the metabolic activity of biofilm-VBNC P. aeruginosa was lower than that of planktonic-VBNC P. aeruginosa. GC-MS/MS analysis showed 51 metabolites with significant differences. KEGG analysis showed that the types and contents of extracellular metabolites from P. aeruginosa in VBNC states were significantly lower than those in the culturable state (p < 0.05), mainly involving in citrate cycle, glutathione metabolism, phenylalanine metabolism, tyrosine metabolism and fatty acid degradation. Also, the contents of most extracellular metabolites from P. aeruginosa in biofilm-VBNC state were lower than those in VBNC planktonic state. The significant differences (p < 0.05) were mainly involved in alanine, aspartate and glutamate metabolism, glycolysis/gluconeogenesis, D-Alanine metabolism and glycerophospholipid metabolism. The result of this research was favorable to the accurate identification of VBNC bacteria, the health risk assessment and scientific control of harmful VBNC bacteria.}, } @article {pmid35093033, year = {2022}, author = {Mirzaei, R and Sabokroo, N and Ahmadyousefi, Y and Motamedi, H and Karampoor, S}, title = {Immunometabolism in biofilm infection: lessons from cancer.}, journal = {Molecular medicine (Cambridge, Mass.)}, volume = {28}, number = {1}, pages = {10}, pmid = {35093033}, issn = {1528-3658}, mesh = {Animals ; *Biofilms/growth & development ; Biomarkers ; Disease Management ; Disease Susceptibility/*immunology/*metabolism ; Energy Metabolism ; *Host-Pathogen Interactions ; Humans ; Immune System/immunology/metabolism ; Infections/diagnosis/*etiology/*metabolism/therapy ; Neoplasms/*complications/etiology/metabolism/therapy ; Organ Specificity ; }, abstract = {BACKGROUND: Biofilm is a community of bacteria embedded in an extracellular matrix, which can colonize different human cells and tissues and subvert the host immune reactions by preventing immune detection and polarizing the immune reactions towards an anti-inflammatory state, promoting the persistence of biofilm-embedded bacteria in the host.

MAIN BODY OF THE MANUSCRIPT: It is now well established that the function of immune cells is ultimately mediated by cellular metabolism. The immune cells are stimulated to regulate their immune functions upon sensing danger signals. Recent studies have determined that immune cells often display distinct metabolic alterations that impair their immune responses when triggered. Such metabolic reprogramming and its physiological implications are well established in cancer situations. In bacterial infections, immuno-metabolic evaluations have primarily focused on macrophages and neutrophils in the planktonic growth mode.

CONCLUSION: Based on differences in inflammatory reactions of macrophages and neutrophils in planktonic- versus biofilm-associated bacterial infections, studies must also consider the metabolic functions of immune cells against biofilm infections. The profound characterization of the metabolic and immune cell reactions could offer exciting novel targets for antibiofilm therapy.}, } @article {pmid35092835, year = {2022}, author = {OmerOglou, E and Karaca, B and Kibar, H and Haliscelik, O and Kiran, F}, title = {The role of microbiota-derived postbiotic mediators on biofilm formation and quorum sensing-mediated virulence of Streptococcus mutans: A perspective on preventing dental caries.}, journal = {Microbial pathogenesis}, volume = {164}, number = {}, pages = {105390}, doi = {10.1016/j.micpath.2022.105390}, pmid = {35092835}, issn = {1096-1208}, mesh = {Biofilms ; *Dental Caries/prevention & control ; Humans ; *Microbiota ; Quorum Sensing ; Streptococcus mutans ; Virulence ; }, abstract = {Dental caries is not only one of the most prevalent diseases worldwide, but also a public health problem, undoubtedly. Among the various species of cariogenic bacteria, Streptococcus mutans is considered to be the major etiological pathogen of dental caries. The present study aimed to assess the influence of microbiota-derived postbiotic mediators (PMs) on the pathogenesis of dental caries. Within this aim, the antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of PMs derived from Lactiplantibacillus plantarum EIR/IF-1, Lactiplantibacillus curvatus EIR/DG-1, and Lactiplantibacillus curvatus EIR/BG-2 were analyzed against S. mutans (ATCC 25175). According to the results, PMs of the strain EIR/IF-1, isolated from infant feces showed the highest inhibitory effect (pH-dependent). Besides, sub-MIC doses of all PMs eliminated the biofilm formation following the co-treatment and pre-treatment assays. The reduction of cell viability and notable changes in biofilm formation were also confirmed both on glass coverslips and ex vivo human tooth surfaces by confocal laser scanning microscopy and scanning electron microscopy. Moreover, sub-MIC values of PMs down-regulated the expression of gtfC, comA, and comX, without any significant growth inhibition. Organic acids, fatty acids, and vitamins in PMs were also reported. Overall, these findings indicated the possible preventive role of microbiota-derived PMs in the pathogenesis of dental caries.}, } @article {pmid35091832, year = {2022}, author = {Zuberi, A and Azam, MW and Khan, AU}, title = {CRISPR Interference (CRISPRi) Mediated Suppression of OmpR Gene in E. coli: An Alternative Approach to Inhibit Biofilm.}, journal = {Current microbiology}, volume = {79}, number = {3}, pages = {78}, pmid = {35091832}, issn = {1432-0991}, mesh = {Bacterial Proteins/genetics ; Biofilms ; Clustered Regularly Interspaced Short Palindromic Repeats ; *Escherichia coli/genetics ; *Escherichia coli Proteins/genetics ; }, abstract = {Biofilm plays an important role in the community and hospital-acquired infections. Especially E. coli biofilm that contributes towards the significant part of medical devices associated with microbial infections. OmpR/EnvZ, a two-component system, is one of the regulatory mechanisms involved in transcription regulation in response to environmental osmolarity changes. The main objective of this study was to elucidate the role of the OmpR/EnvZ two-component system in regulating the biofilm through curli and fimbriae (FimH gene), a contrary approach towards biofilm inhibition. In this study, the CRISPRi technique was used to suppress the expression of the OmpR gene. The RT-PCR assay was performed to quantify mRNA gene expression of curli and biofilm producing genes, and the data were further confirmed by different microscopic, spectroscopic and biofilm quantification assay (Crystal Violet). It is the first time we have shown downregulation of the OmpR gene in biofilm causing clinical isolates of E. coli, which further suppressed the FimH gene, leading to biofilm reduction. The crystal violet assay and microscopic studies also confirmed the biofilm reduction. We conclude that the OmpR gene of the OmpR/EnvZ two-component system could be one of the targets for biofilm mediated infection intervention. Our findings open new vistas to explore the pathways and targets to control biofilm mediated infections.}, } @article {pmid35091030, year = {2022}, author = {Carrera-Salinas, A and González-Díaz, A and Vázquez-Sánchez, DA and Camoez, M and Niubó, J and Càmara, J and Ardanuy, C and Martí, S and Domínguez, MÁ and , }, title = {Staphylococcus aureus surface protein G (sasG) allelic variants: correlation between biofilm formation and their prevalence in methicillin-resistant S. aureus (MRSA) clones.}, journal = {Research in microbiology}, volume = {173}, number = {3}, pages = {103921}, doi = {10.1016/j.resmic.2022.103921}, pmid = {35091030}, issn = {1769-7123}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Clone Cells ; Humans ; Membrane Proteins ; Methicillin Resistance ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Prevalence ; *Staphylococcal Infections/epidemiology ; Staphylococcus aureus ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) may persist for long periods due to biofilm formation. The objective of this study was to describe biofilm formation in association with the presence of S. aureus surface protein G (sasG) and its allelic variants in MRSA bacteraemia isolates from endemic (CC5, CC8, CC22) and sporadic clones in Spain (2008-2015). Crystal violet staining was used to assess biofilm formation; DNA microarray, RT-qPCR, and long-read whole genome sequencing were applied to determine the presence, expression and structure of sasG, respectively. The endemic CC5 and CC8 clones produced more biofilm than the sporadic clones; these endemic clones carried sasG allelic variant 1. Otherwise, sporadic clones, with less biofilm formation, showed either an absence of sasG (65%) or the presence of allelic variant 2 (35%). Variants 1 and 2 differed in the expression of sasG (1.56 ± 1.20 and 0.37 ± 0.32, respectively). The analysis of a large cohort of closed S. aureus genomes available on the NCBI database confirmed the distribution of the two allelic variants with low amino acid identity (68.1%) among endemic and sporadic clones. SasG variant 1 present in the major CC5 and CC8 clones was correlated with increased biofilm formation and may represent an important virulence determinant.}, } @article {pmid35087504, year = {2021}, author = {Ballén, V and Gabasa, Y and Ratia, C and Sánchez, M and Soto, S}, title = {Correlation Between Antimicrobial Resistance, Virulence Determinants and Biofilm Formation Ability Among Extraintestinal Pathogenic Escherichia coli Strains Isolated in Catalonia, Spain.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {803862}, pmid = {35087504}, issn = {1664-302X}, abstract = {Escherichia coli is a well-characterized bacterium highly prevalent in the human intestinal tract and the cause of many important infections. The aim of this study was to characterize 376 extraintestinal pathogenic E. coli strains collected from four hospitals in Catalonia (Spain) between 2016 and 2017 in terms of antimicrobial resistance, siderophore production, phylogroup classification, and the presence of selected virulence and antimicrobial resistance genes. In addition, the association between these characteristics and the ability to form biofilms was also analyzed. The strains studied were classified into four groups according to their biofilm formation ability: non-biofilm formers (15.7%), weak (23.1%), moderate (35.6%), and strong biofilm formers (25.6%). The strains were highly resistant to ciprofloxacin (48.7%), trimethoprim-sulfamethoxazole (47.9%), and ampicillin (38%), showing a correlation between higher resistance to ciprofloxacin and lower biofilm production. Seventy-three strains (19.4%) were ESBL-producers. However, no relationship between the presence of ESBL and biofilm formation was found. The virulence factor genes fimH (92%), pgaA (84.6%), and irp1 (77.1%) were the most prevalent in all the studied strains. A statistically significant correlation was found between biofilm formation and the presence of iroN, papA, fimH, sfa, cnf, hlyA, iutA, and colibactin-encoding genes clbA, clbB, clbN, and clbQ. Interestingly, a high prevalence of colibactin-encoding genes (19.9%) was observed. Colibactin is a virulence factor, which interferes with the eukaryotic cell cycle and has been associated with colorectal cancer in humans. Most colibactin-encoding E. coli isolates belonged to phylogroup B2, exhibited low antimicrobial resistance but moderate or high biofilm-forming ability, and were significantly associated with most of the virulence factor genes tested. Additionally, the analysis of their clonal relatedness by PFGE showed 48 different clusters, indicating a high clonal diversity among the colibactin-positive strains. Several studies have correlated the pathogenicity of E. coli and the presence of virulence factor genes; however, colibactin and its relationship to biofilm formation have been scarcely investigated. The increasing prevalence of colibactin in E. coli and other Enterobacteriaceae and the recently described correlation with biofilm formation, makes colibactin a promising therapeutic target to prevent biofilm formation and its associated adverse effects.}, } @article {pmid35086381, year = {2022}, author = {Lan, Y and Yang, J and Liu, X and Zhao, H and Zhang, X and Yin, X and Yang, C and Yang, K and Liu, Y}, title = {Inhibition efficiency of 304-Cu stainless steel against oral bacterial biofilm.}, journal = {Journal of applied biomaterials & functional materials}, volume = {20}, number = {}, pages = {22808000211065259}, doi = {10.1177/22808000211065259}, pmid = {35086381}, issn = {2280-8000}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Mice ; NIH 3T3 Cells ; *Stainless Steel ; Streptococcus mutans ; }, abstract = {PURPOSE: This study aims to evaluate the antibacterial properties of 304 Cu-bearing stainless steel (SS) with different Cu contents (0, 2.5, 4.5 wt.%) against oral biofilms of Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and their mixture.

METHODS: Bacterial biofilms on the surface of 304-Cu SS were characterized by plate counting, 4', 6-diamidino-2-phenylindole (DAPI) staining with aid of sanning electron microscopy (SEM) and 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT). In addition, the inhibition zone method was also employed to evaluate the antibacterial properties of 304-Cu SS. Cell Counting Kit-8 (CCK-8) and flow cytometry were used to assess the cytotoxicity and apoptosis rate of 304-Cu SS, respectively.

RESULTS: 304-4.5Cu SS could effectively inhibit the attachment, formation, activity, and metabolism of bacterial biofilm, possessing the best antibacterial properties exceeding 99.9% of antibacterial rate against S. mutans, S. sanguinis, and their mixture. The diameters of inhibition zones to S. mutans and S. sanguinis on the surface of 304-4.5Cu SS were 21.7 and 14.7 mm, respectively. The results of cell experiments in vitro showed that both 304-2.5Cu SS and 304-4.5Cu SS had no evident cytotoxicity with an identical grade 1. The apoptosis rate exhibited a gradually increased tendency with increase of the Cu content in 304 SS.

CONCLUSIONS: 304-4.5Cu SS without cytotoxic effect on NIH3T3 cells has obvious antibacterial activity against S. mutans, S. sanguinis and their mixture.

CLINICAL SIGNIFICANCE: The Cu-bearing stainless steel provides a new solution to be used as oral orthodontic devices for inhibiting oral microflora imbalance and enamel demineralization.}, } @article {pmid35086219, year = {2022}, author = {Lodha, D and Karolia, R and Sharma, S and Joseph, J and Das, T and Dave, VP}, title = {Biofilm formation and its effect on the management of culture-positive bacterial endophthalmitis.}, journal = {Indian journal of ophthalmology}, volume = {70}, number = {2}, pages = {472-476}, pmid = {35086219}, issn = {1998-3689}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Endophthalmitis/diagnosis/drug therapy/etiology ; *Eye Infections, Bacterial/complications/diagnosis/drug therapy ; Humans ; Prospective Studies ; Retrospective Studies ; Visual Acuity ; Vitrectomy/adverse effects ; }, abstract = {PURPOSE: To compare the clinicomicrobiological features and outcomes in patients with infectious endophthalmitis caused by biofilm-positive (BP) and biofilm-negative (BN) bacteria.

METHODS: This was a prospective, interventional, comparative, nonrandomized, consecutive case series. Culture-positive bacterial endophthalmitis cases from August 1, 2018 to July 31[st] 31, 2019 were included. All vitreous samples were tested for biofilm using crystal violet plate and XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) methods and classified as BN and BP. The antibiotic susceptibility of all organisms was determined. Anatomic and functional success was defined as intraocular pressure >5 mm Hg and final best-corrected vision ≥20/400, respectively, at last visit.

RESULTS: There were 50 eyes in the BN group and 33 eyes in the BP group. BN group eyes required 2.86 ± 1.45 surgical interventions, and BP group eyes needed surgical 6.36 ± 2.89 interventions, P < 0.0001, 95% Confidence Interval, CI: 2-4. Median follow-up was 6 and 5 months, respectively (P = 0.33). Final logMAR vision was a median of 1.2 and 1.9 respectively; P = 0.0005, 95% C.I.: 0.4-1.7. Functional success was achieved in 44% and 21.2% (P = 0.03, 95% C.I.: 1.86%-40.08%) and anatomic success was achieved in 68% and 42.42%, respectively (P = 0.02, 95% C.I.: 3.85%-45.47%). The antimicrobial resistance patterns between the two groups were comparable.

CONCLUSION: Endophthalmitis caused by the biofilm-forming bacteria needs a greater number of surgical interventions. The anatomic and functional outcomes are poorer than non-biofilm-forming bacterial endophthalmitis. The increased virulence and poorer outcomes can be hypothesized to be due to the physical barrier effect of the biofilm on the antibiotics.}, } @article {pmid35085920, year = {2022}, author = {Zhao, T and Chen, J and Liu, S and Yang, J and Wu, J and Miao, L and Sun, W}, title = {Transcriptome analysis of Fusobacterium nucleatum reveals differential gene expression patterns in the biofilm versus planktonic cells.}, journal = {Biochemical and biophysical research communications}, volume = {593}, number = {}, pages = {151-157}, doi = {10.1016/j.bbrc.2021.11.075}, pmid = {35085920}, issn = {1090-2104}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Fusobacterium nucleatum/genetics/*metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Humans ; Plankton/genetics/growth & development/*metabolism ; *Transcriptome ; Virulence ; }, abstract = {As a chronic infectious disease, periodontitis can cause gum recession, loss of alveolar bone, loosening of teeth, and even loss of teeth. Dental plaque biofilm is the initiating factor for the occurrence and development of periodontitis. Fusobacterium nucleatum (F. nucleatum) plays a vital role in the structure and ecology of dental plaque biofilms. It is a bridge between early and late colonization bacteria in dental plaque. Understanding the molecular mechanism of F. nucleatum during biofilm development is essential to control periodontitis. This study aimed to determine gene expression profiles of the F. nucleatum strain, ATCC 25586, in the planktonic and biofilm phase through RNA-sequencing approach. The results were confirmed by quantitative reverse transcriptase PCR (RT-qPCR). The results clearly illustrate the difference in gene expression of F. nucleatum under planktonic and biofilms. A total of 110 genes were differentially expressed by F. nucleatum in the biofilm state compared with the planktonic state. The 25 upregulated genes in the biofilm state were mainly related to carbohydrate and amino acid metabolism, while the 85 downregulated genes were primarily associated with cell growth, division, and oxidative stress; most of the upregulated genes of F. nucleatum involved in virulence and oral malodor. Furthermore, the transcriptome analysis and antibacterial activity test also identified Lysine might exhibit the antibacterial and antibiofilm activity of F. nucleatum for the first time. These new findings could provide caveats for future studies on the regulation and maintenance of plaque biofilm and the development of biomarkers for periodontitis.}, } @article {pmid35085729, year = {2022}, author = {Zhang, L and Bera, H and Wang, H and Wang, J and Guo, Y and Shi, C and Cun, D and Moser, C and Høiby, N and Yang, M}, title = {Combination and nanotechnology based pharmaceutical strategies for combating respiratory bacterial biofilm infections.}, journal = {International journal of pharmaceutics}, volume = {616}, number = {}, pages = {121507}, doi = {10.1016/j.ijpharm.2022.121507}, pmid = {35085729}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacterial Infections/drug therapy/microbiology ; Biofilms ; Extracellular Polymeric Substance Matrix ; Humans ; Nanotechnology ; Pharmaceutical Preparations ; *Respiratory Tract Infections/drug therapy/microbiology ; }, abstract = {Respiratory infections are one of the major global health problems. Among them, chronic respiratory infections caused by biofilm formation are difficult to treat because of both drug tolerance and poor drug penetration into the complex biofilm structure. A major part of the current research on combating respiratory biofilm infections have been focused on destroying the matrix of extracellular polymeric substance and eDNA of the biofilm or promoting the penetration of antibiotics through the extracellular polymeric substance via delivery technologies in order to kill the bacteria inside. There are also experimental data showing that certain inhaled antibiotics with simple formulations can effectively penetrate EPS to kill surficially located bacteria and centrally located dormant bacteria or persisters. This article aims to review recent advances in the pharmaceutical strategies for combating respiratory biofilm infections with a focus on nanotechnology-based drug delivery approaches. The formation and characteristics of bacterial biofilm infections in the airway mucus are presented, which is followed by a brief review on the current clinical approaches to treat respiratory biofilm infections by surgical removal and antimicrobial therapy, and also the emerging clinical treatment approaches. The current combination of antibiotics and non-antibiotic adjuvants to combat respiratory biofilm infections are also discussed.}, } @article {pmid35084583, year = {2022}, author = {Ashwath, P and Deekshit, VK and Rohit, A and Dhinakaran, I and Karunasagar, I and Karunasagar, I and Akhila, DS}, title = {Biofilm Formation and Associated Gene Expression in Multidrug-Resistant Klebsiella pneumoniae Isolated from Clinical Specimens.}, journal = {Current microbiology}, volume = {79}, number = {3}, pages = {73}, pmid = {35084583}, issn = {1432-0991}, support = {NUFR1/2018/10/17//nitte (deemed to be) university/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Gene Expression ; Humans ; *Klebsiella Infections ; *Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; beta-Lactamases/genetics ; }, abstract = {Biofilms reduce the bacterial growth rate, inhibit antibiotic penetration, lead to the development of persister cells and facilitate genetic exchange. The biofilm-associated Klebsiella pneumoniae infections have not been well studied, and their implications in overcoming the effects of antimicrobial therapy are yet to be fully understood. Hence this study evaluated the antibiotic resistance pattern, antibiotic resistance determinants of extended-spectrum beta-lactamase (ESBL) family. Biofilm-forming ability of seventy multidrug-resistant clinical isolates of K. pneumoniae and the biofilm-associated genes of representative biofilm formers from a tertiary care hospital were also assessed. The K. pneumoniae isolated from urine exhibited resistance towards ceftazidime, nalidixic acid and meropenem. Isolates from blood were resistant to cefuroxime. Higher rates of resistance were observed towards cefuroxime, nalidixic acid, and meropenem for the isolates from the endotracheal aspirate. Extended spectrum beta-lactamase production by CLSI's disc diffusion-based confirmation test revealed all the K. pneumoniae to be as ESBL producers. Most of the isolates harboured the bla gene variants, blaSHV and blaTEM. Majority of the isolates were colistin sensitive. 97.1% of the K. pneumoniae produced biofilm. K. pneumoniae isolated from pus and blood produced fully established biofilms. Strong biofilm formers were sensitive to co-trimoxazole and ciprofloxacin. Moderate biofilm formers exhibited sensitivity towards meropenem and imipenem. Expression of the fimH gene was increased, while mrkD showed reduced expression among the strong biofilm formers. Moderate biofilm formers showed variable expression of the genes associated with the biofilm formation. The weak and non-biofilm formers showed reduced expression of both the fimbrial genes. Multidrug-resistant isolates produced ESBLs and formed well-established biofilms.}, } @article {pmid35084224, year = {2022}, author = {Guéneau, V and Piard, JC and Frayssinet, B and Loux, V and Chiapello, H and Plateau-Gonthier, J and Castex, M and Briandet, R}, title = {Genome Sequence of Bacillus velezensis P1, a Strain Isolated from a Biofilm Captured on a Pig Farm Building.}, journal = {Microbiology resource announcements}, volume = {11}, number = {2}, pages = {e0121921}, pmid = {35084224}, issn = {2576-098X}, abstract = {The genome of the Bacillus velezensis P1 strain isolated from a biofilm on the wall of a pig farm was sequenced. The strain harbors many surface colonization genes involved in surfactant, matrix, and antibacterial synthesis.}, } @article {pmid35084053, year = {2022}, author = {Sreckovic, S and Ladjevic, N and Jokanovic, M and Vracevic, D and Milovanovic, D and Simic, M and Korica, S and Kadija, M}, title = {Rifampicin-induced fever during treatment against staphylococcal biofilm in a patient with periprosthetic joint infection.}, journal = {British journal of clinical pharmacology}, volume = {88}, number = {8}, pages = {3887-3890}, doi = {10.1111/bcp.15248}, pmid = {35084053}, issn = {1365-2125}, mesh = {Aged ; Anti-Bacterial Agents/adverse effects ; Biofilms ; Ciprofloxacin/adverse effects ; Humans ; Male ; *Prosthesis-Related Infections/drug therapy ; Retrospective Studies ; Rifampin/adverse effects ; }, abstract = {Periprosthetic joint infection (PJI) after total knee arthroplasty remains a challenging complication. The treatment options for PJI include different procedures; however, regardless of the strategy, antibiotics are required. The combination of different antibiotics increased the rates of PJI eradication. For almost 3 decades, rifampicin has been used as part of antibiotic therapy for PJI. Drug fever, a febrile response that coincides with the onset of drug administration and disappears after drug discontinuation in the absence of other underlying conditions that could cause fever, is frequently misdiagnosed. We present the case of a 72-year-old man with PJI 6 months after total knee arthroplasty. Two-stage revision surgery was followed by culture-directed antibiotic treatment (ciprofloxacin and rifampicin) against Staphylococcus aureus isolated from the periprosthetic tissue. On the fifth day of antibiotic treatment, the patient became febrile and, in the next 5 days, he had an intermittent fever of up to 40°C, although he showed clinical improvement. The patient was normotensive without a maculopapular rash, urticaria or clotting abnormalities. A drug fever was suspected, and rifampicin was discontinued. A re-challenge test was performed, and the fever recurred. Antibiotic treatment with ciprofloxacin was continued and, after 12 months of follow-up, the patient was doing well. Clinicians should be aware that fever could be a clinical presentation of drug fever. If it occurs during an infection, drug fever could necessitate additional diagnostic procedures for further evaluation, inadequate antibiotic therapy and prolonged hospitalisation.}, } @article {pmid35081225, year = {2022}, author = {Silva, RVDR and Jarros, IC and Del Bel Cury, AA and Sidhu, SK and Silva, S and Negri, MFN and Pascotto, RC}, title = {Evaluation of biofilm formation on acrylic resin surfaces coated with silicon dioxide: an in situ study.}, journal = {Brazilian oral research}, volume = {36}, number = {}, pages = {e007}, doi = {10.1590/1807-3107bor-2022.vol36.0007}, pmid = {35081225}, issn = {1807-3107}, mesh = {*Acrylic Resins ; Biofilms ; Candida albicans ; *Denture Bases ; Humans ; Silicon Dioxide ; Surface Properties ; }, abstract = {Biofilm on acrylic resin dental prostheses may cause gingival inflammation. This study evaluated the influence of a silicon dioxide coating layer applied onto acrylic resin on the adhesion of microorganisms. Blocks (5 x 5 x 3 mm) of acrylic resin were evaluated for surface roughness and divided into two groups: control (CG) and coated with silicon dioxide (LG group). The specimens were evaluated by scanning electron microscopy (n = 1) and by contact angle analysis (n = 3). For the in situ study, 20 volunteers wore acrylic palatal devices containing three samples from each group (n = 60) for 2 days. The biofilm formed was quantified by metabolic activity and total biomass using the crystal violet assay. The results were subjected to Bartlett's normality test and Gamma model with random effect for the response variable (α = 5%). The mean contact angle of the coated group was significantly lower than that of the uncoated group (p < 0.05). The metabolic activity of microorganisms in the biofilm on the blocks treated with coating was significantly lower than that of control blocks (p = 0.02). Regarding the amount of extracellular matrix produced by the microorganisms, there was no difference between the CG and LG group (p = 0.05). The application of a silicon dioxide coating on acrylic resin reduced the activity of the polymicrobial biofilm formed in situ. This coating may be advantageous for patients with conventional complete dentures or implants made of acrylic resin and who have motor difficulties that prevent them from cleaning their prostheses properly.}, } @article {pmid35077639, year = {2022}, author = {Wang, B and Jin, T and Xu, Q and Liu, H and Ye, Z and Chen, H}, title = {Correction to "Direct Loading and Tunable Release of Antibiotics from Polyelectrolyte Multilayers To Reduce Bacterial Adhesion and Biofilm Formation".}, journal = {Bioconjugate chemistry}, volume = {33}, number = {2}, pages = {427}, doi = {10.1021/acs.bioconjchem.2c00026}, pmid = {35077639}, issn = {1520-4812}, } @article {pmid35075919, year = {2023}, author = {Webber, B and Pottker, ES and Rizzo, NN and Núncio, AS and Peixoto, CS and Mistura, E and Dos Santos, LR and Rodrigues, LB and do Nascimento, VP}, title = {Surface conditioning with bacteriophages reduces biofilm formation of Salmonella Heidelberg.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {29}, number = {3}, pages = {275-283}, doi = {10.1177/10820132221074783}, pmid = {35075919}, issn = {1532-1738}, mesh = {*Bacteriophages ; Polystyrenes ; Salmonella ; Biofilms ; }, abstract = {Salmonella remains one of the most common foodborne pathogens worldwide, and its resistance to antimicrobials has increased considerably over the years. In this context, was evaluated the action of three bacteriophages isolated or combined in inhibiting the adhesion and removal of Salmonella Heidelberg biofilm on a polystyrene surface. The bacteriophages UPF_BP1, UPF_BP2, UPF_BP3 and a pool of them were used for biocontrol of Salmonella Heidelberg biofilms on polystyrene surface in the action times of 3, 6 and 9 h. Individual and combined phages exhibited reductions in Salmonella Heidelberg adhesion of up to 83.4% and up to 64.0% in removal of preformed biofilm. The use of synergistic combinations between the phages is the most indicated option due to its potential to reduce biofilms. The use of the bacteriophage pool in surface conditioning is an alternative in the control of Salmonella Heidelberg biofilms.}, } @article {pmid35075429, year = {2022}, author = {Zamani, S and Mohammadi, A and Hajikhani, B and Abiri, P and Fazeli, M and Nasiri, MJ and Dadashi, M and Goudarzi, M and Haghighi, M}, title = {Mupirocin-Resistant Staphylococcus aureus in Iran: A Biofilm Production and Genetic Characteristics.}, journal = {BioMed research international}, volume = {2022}, number = {}, pages = {7408029}, pmid = {35075429}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; Iran ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Mupirocin/pharmacology ; *Staphylococcal Infections/drug therapy/epidemiology/genetics ; Staphylococcus aureus/genetics ; }, abstract = {The spread of mupirocin-resistant Staphylococcus aureus strains in hospitals and communities is a universal challenge. Limited data is available on the genetic features of high-level mupirocin resistant- (HLMUPR-) S. aureus isolates in Tehran. In the present research, we investigated 48 high-level mupirocin resistance S. aureus by antimicrobial activity, virulence analysis, biofilm formation, multilocus sequence typing (MLST), and staphylocoagulase (SC) typing. All the HLMUPR strains were positive for mupA gene. The frequency of multidrug resistance was 97.9%. Twenty-one (43.8%) were toxinogenic with 14 producing pvl (29.2%), 5 tst (10.4%), and two eta (4.2%). Among the HLMUPR isolates, biofilm production was detected in 45 (89.6%) isolates with complete dominance clfB, clfA genes, and a noticeably high frequency fnbA (95.8%), followed by fnbB (93.8%), eno and icaD (each 83.3%), sdrC (81.3%), ebps (79.2%), icaA (75%), sdrD (66.7%), fib (60.4%), sdrE (50%), cna (41.7%), and bap (4.2%). Coagulase typing distinguished isolates into four genotypic patterns including III (50%), II (27.1%), and type IVa (22.9%). A total of three clonal complexes (CCs) and 4 sequence types (STs) including CC/ST22 as the most prevalent (52.1%), CC8/ST239 (20.8%), CC/ST8 (16.7%), and CC/ST5 (10.4%) were identified in current work. According to our analysis, nonbiofilm producer isolates belonged to CC8/ST239 (6.3%) and CC/ST8 (4.2%). Fusidic acid-resistant isolates belonged to CC/ST45 (n = 3) and CC8/ST239 (n = 1). Observations highlighted the circulation of the CC/ST22 HLMUPR S. aureus strains with strong biofilm-production ability in our hospitals, indicating the possibility of transmission of this type between community and hospital.}, } @article {pmid35075262, year = {2022}, author = {Jordan, SC and Hall, PR and Daly, SM}, title = {Nonconformity of biofilm formation in vivo and in vitro based on Staphylococcus aureus accessory gene regulator status.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {1251}, pmid = {35075262}, issn = {2045-2322}, support = {R01 AI145324/AI/NIAID NIH HHS/United States ; P20 GM121176/GM/NIGMS NIH HHS/United States ; AI45324/NH/NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*physiology ; Biofilms/*growth & development ; Culture Techniques ; Female ; Mice, Inbred BALB C ; Quorum Sensing ; Staphylococcus aureus/*physiology ; Trans-Activators/*physiology ; }, abstract = {Staphylococcus aureus is an opportunistic, pathogenic bacteria that causes significant morbidity and mortality. As antibiotic resistance by S. aureus continues to be a serious concern, developing novel drug therapies to combat these infections is vital. Quorum sensing inhibitors (QSI) dampen S. aureus virulence and facilitate clearance by the host immune system by blocking quorum sensing signaling that promotes upregulation of virulence genes controlled by the accessory gene regulator (agr) operon. While QSIs have shown therapeutic promise in mouse models of S. aureus skin infection, their further development has been hampered by the suggestion that agr inhibition promotes biofilm formation. In these studies, we investigated the relationship between agr function and biofilm growth across various S. aureus strains and experimental conditions, including in a mouse model of implant-associated infection. We found that agr deletion was associated with the presence of increased biofilm only under narrow in vitro conditions and, crucially, was not associated with enhanced biofilm development or enhanced morbidity in vivo.}, } @article {pmid35074731, year = {2022}, author = {Anguita, J and Pizarro, G and Vargas, IT}, title = {Mathematical modelling of microbial corrosion in carbon steel due to early-biofilm formation of sulfate-reducing bacteria via extracellular electron transfer.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {145}, number = {}, pages = {108058}, doi = {10.1016/j.bioelechem.2022.108058}, pmid = {35074731}, issn = {1878-562X}, mesh = {Biofilms ; Carbon ; Corrosion ; *Desulfovibrio/metabolism ; Electrons ; Models, Theoretical ; *Steel ; Sulfates/metabolism ; }, abstract = {Sulfate-reducing bacteria (SRB) are the most studied microorganisms related to severe episodes of microbially influenced corrosion (MIC). A mechanism used by SRB to corrode steel alloys is the extracellular electron transfer (EET), which was described by the biocatalytic cathodic sulfate reduction (BCSR) theory. This theory was supported by several experimental research and some mathematical approaches. However, mathematical modelling that represents the effect of the EET on pit development and the subsequent changes in surface topography has not been reported. In this study, a mechanistic mathematical model of microbial corrosion induced by SRB through EET was developed and implemented. The developed model used data from previously reported experiments to describe the phenomenon and define stoichiometric and kinetic parameters. Results of biofilm development and growth-associated corrosion (i.e. weight loss and maximum pit depths) obtained by simulations were similar to experimental evidence reported in the literature. These simulations reveal that the main parameters that control MIC are the maintenance coefficient of SRB, the initial planktonic cell concentration, and the probability of surface colonization.}, } @article {pmid35074638, year = {2022}, author = {Rahimi, E and Offoiach, R and Lekka, M and Fedrizzi, L}, title = {Electronic properties and surface potential evaluations at the protein nano-biofilm/oxide interface: Impact on corrosion and biodegradation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {212}, number = {}, pages = {112346}, doi = {10.1016/j.colsurfb.2022.112346}, pmid = {35074638}, issn = {1873-4367}, mesh = {Biofilms ; Corrosion ; Electronics ; *Metals/chemistry ; *Oxides ; Surface Properties ; }, abstract = {The formation of a protein nano-biofilm, which exhibits a special electronic behavior, on the surface of metals or oxide biomaterials considerably influences the crucial subsequent interactions, particularly the corrosion and biodegradation processes. This study discusses the impact of electrical surface potential (ESP) of a single or nano-biofilm of albumin protein on the electrochemical interactions and electronic property evolutions (e.g., charge carriers, space charge capacitance (SCC), and band bending) occurring on the surface oxide of CoCrMo implants. Scanning Kelvin probe force microscopy (SKPFM) results indicated that ESP or surface charge distribution on a single or nano-biofilm of the albumin protein is lower than that of a CoCrMo complex oxide layer, which hinders the charge transfer at the protein/electrolyte interface. Using a complementary approach, which involved performing Mott-Schottky analysis at the electrolyte/protein/oxide interface, it was revealed that the albumin protein significantly increases the SCC magnitude and number of n-type charge carrier owing to increased band bending at the SCC/protein interface; this facilitated the acceleration of metal ion release and metal-protein complex formation. The nanoscale SKPFM and electrochemical analyses performed in this study provide a better understanding of the role of protein molecules in corrosion/biodegradation of metallic biomaterials at the protein nano-biofilm/oxide interface.}, } @article {pmid35073796, year = {2022}, author = {Lima, WG and Batista Filho, FL and Lima, IP and Simião, DC and Brito, JCM and da Cruz Nizer, WS and Cardoso, VN and Fernandes, SOA}, title = {Antibacterial, anti-biofilm, and anti-adhesive activities of melittin, a honeybee venom-derived peptide, against quinolone-resistant uropathogenic Escherichia coli (UPEC).}, journal = {Natural product research}, volume = {36}, number = {24}, pages = {6381-6388}, doi = {10.1080/14786419.2022.2032047}, pmid = {35073796}, issn = {1478-6427}, mesh = {Humans ; *Uropathogenic Escherichia coli ; Melitten/pharmacology ; *Quinolones/pharmacology ; *Bee Venoms/pharmacology ; Adhesives ; Biofilms ; Anti-Bacterial Agents/pharmacology ; Microbial Sensitivity Tests ; *Urinary Tract Infections/drug therapy/microbiology ; }, abstract = {Here, we demonstrated the in vitro and in vivo antibacterial and anti-biofilm activities of melittin, a peptide derived from honeybee venom, against uropathogenic Escherichia coli (UPEC) resistant to quinolones. The minimum inhibitory concentration (MIC) of melittin varied from 0.5 to 8 μM. The bactericidal effect was considered rapid and potent (ranging from 3.0 to 6.0 h after incubation) against a quinolone-resistant and Extended Spectrum Beta-lactamase (ESBL)-producing UPEC strain. Prior exposure to melittin did not reduce the MIC of the quinolones tested, but it decreased the MIC of ceftizoxime by 8-fold due to its ability to form pores in the membrane. Furthermore, melittin disrupted mature biofilms (39.58% at 32 μM) and inhibited the adhesion of this uropathogen to the surfaces of urethral catheter. These results show that melittin is a promising molecule that can be incorporated into invasive urethral medical devices to prevent urinary infections caused by multidrug-resistant UPECs.}, } @article {pmid35073789, year = {2022}, author = {Burgos-Edwards, A and Franco, S and Salinas, C and Florentín, M and García, L and Guillén, R and Alvarenga, N}, title = {In vitro antibacterial activity, biofilm formation inhibition and chromatographic profile of methanolic extracts of two Pterocaulon species against MRSA.}, journal = {Natural product research}, volume = {36}, number = {24}, pages = {6364-6368}, doi = {10.1080/14786419.2022.2031185}, pmid = {35073789}, issn = {1478-6427}, mesh = {Child ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Methanol ; *Asteraceae/chemistry ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/pharmacology/chemistry ; Plant Extracts/pharmacology ; Biofilms ; }, abstract = {The methanolic extracts of Pterocaulon alopecuroides and Pterocaulon angustifolium were assayed for antibacterial activity and biofilm formation inhibition of four community-acquired-MRSA isolates representative of ST30 t975, ST30 t021, ST5 t311, and ST4335 t008 clones that are responsible for invasive infections in Paraguayan children. Both Pterocaulon extracts showed significant antibacterial activity with a minimum inhibitory concentration of 200 µg/mL against the four isolates. P. angustifolium showed inhibition of biofilm formation for the four isolates, whereas P. alopecuroides showed inhibition for three of them. The chemical constituents were identified by liquid chromatography coupled to tandem mass spectrometry. Phenolic compounds were detected in the two species as well as coumarins. These results showed that these plants are sources of compounds with activity against MRSA.}, } @article {pmid35072960, year = {2022}, author = {Schiffer, CJ and Schaudinn, C and Ehrmann, MA and Vogel, RF}, title = {SxsA, a novel surface protein mediating cell aggregation and adhesive biofilm formation of Staphylococcus xylosus.}, journal = {Molecular microbiology}, volume = {117}, number = {5}, pages = {986-1001}, doi = {10.1111/mmi.14884}, pmid = {35072960}, issn = {1365-2958}, mesh = {*Adhesives/metabolism ; Biofilms ; *Membrane Proteins/metabolism ; Staphylococcus/genetics/metabolism ; }, abstract = {Biofilm formation of staphylococci has been an emerging field of research for many years. However, the underlying molecular mechanisms are still not fully understood and vary widely between species and strains. The aim of this study was to identify new effectors impacting biofilm formation of two Staphylococcus xylosus strains. We identified a novel surface protein conferring cell aggregation, adherence to abiotic surfaces, and biofilm formation. The S. xylosus surface protein A (SxsA) is a large protein occurring in variable sizes. It lacks sequence similarity to other staphylococcal surface proteins but shows similar structural domain organization and functional features. Upon deletion of sxsA, adherence of S. xylosus strain TMW 2.1523 to abiotic surfaces was completely abolished and significantly reduced in TMW 2.1023. Macro- and microscopic aggregation assays further showed that TMW 2.1523 sxsA mutants exhibit reduced cell aggregation compared with the wildtype. Comparative genomic analysis revealed that sxsA is part of the core genome of S. xylosus, Staphylococcus paraxylosus, and Staphylococcus nepalensis and additionally encoded in a small group of Staphylococcus cohnii and Staphylococcus saprophyticus strains. This study provides insights into protein-mediated biofilm formation of S. xylosus and identifies a new cell wall-associated protein influencing cell aggregation and biofilm formation.}, } @article {pmid35072796, year = {2022}, author = {Liu, S and Dong, F and Zhang, D and Zhang, J and Wang, X}, title = {Effect of microfluidic channel geometry on Bacillus subtilis biofilm formation.}, journal = {Biomedical microdevices}, volume = {24}, number = {1}, pages = {11}, pmid = {35072796}, issn = {1572-8781}, mesh = {*Bacillus subtilis ; Biofilms ; Extracellular Matrix ; *Microfluidics ; Stress, Mechanical ; }, abstract = {Biofilms are microbial colonies encased in an extracellular polymer matrix self-secreted through bacterial proliferation and differentiation. Biofilms exist almost everywhere such as sewers, rivers and oceans. In the fluid environment, the formation of biofilms is closely related to the relevant parameters of the flow field, such as the shear stress, the secondary flow, and the Reynolds number. In this paper, we use microfluidic channels made of polydimethylsiloxane to study the channel-geometry effect on Bacillus subtilis biofilms formation, such as the biofilm adhesion and structure. Our study shows that both the shear stress and the secondary flow play roles in the biofilm adhesion at the initial stage, the shear stress decides whether the biofilm adheres, if yes, then the secondary flow determines the adhesion rate. Our study further shows that after the biofilm forms, its structure evolves from loose to dense, with a concomitant 20-times rise in adhesion. Our study provides new insights into the adhesion of biofilms in natural and industrial fluid environments and helps understand the growth of biofilms.}, } @article {pmid35069493, year = {2021}, author = {Jarzynka, S and Spott, R and Tchatchiashvili, T and Ueberschaar, N and Martinet, MG and Strom, K and Kryczka, T and Wesołowska, A and Pletz, MW and Olędzka, G and Makarewicz, O}, title = {Human Milk Oligosaccharides Exhibit Biofilm Eradication Activity Against Matured Biofilms Formed by Different Pathogen Species.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {794441}, pmid = {35069493}, issn = {1664-302X}, abstract = {Human milk oligosaccharides (HMOs) have been shown to exhibit plenty of benefits for infants, such as prebiotic activity shaping the gut microbiota and immunomodulatory and anti-inflammatory activity. For some pathogenic bacteria, antimicrobial activity has been proved, but most studies focus on group B streptococci. In the present study, we investigated the antimicrobial and antibiofilm activities of the total and fractionated HMOs from pooled human milk against four common human pathogenic Gram-negative species (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Burkholderia cenocepacia) and three Gram-positive species (Staphylococcus aureus, Enterococcus faecium, and Enterococcus faecalis). The activity of HMOs against enterococci and B. cenocepacia are addressed here for the first time. We showed that HMOs exhibit a predominant activity against the Gram-positive species, with E. faecalis being the most sensitive to the HMOs, both in planktonic bacteria and in biofilms. In further tests, we could exclude fucosyllactose as the antibacterial component. The biological significance of these findings may lie in the prevention of skin infections of the mother's breast as a consequence of breastfeeding-induced skin laceration and/or protection of the infants' nasopharynx and lung from respiratory pathogens such as staphylococci.}, } @article {pmid35069474, year = {2021}, author = {Rao, L and Sheng, Y and Zhang, J and Xu, Y and Yu, J and Wang, B and Zhao, H and Wang, X and Guo, Y and Wu, X and Song, Z and Yu, F and Zhan, L}, title = {Small-Molecule Compound SYG-180-2-2 to Effectively Prevent the Biofilm Formation of Methicillin-Resistant Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {770657}, pmid = {35069474}, issn = {1664-302X}, abstract = {The resistance of methicillin-resistant Staphylococcus aureus (MRSA) has augmented due to the abuse of antibiotics, bringing about difficulties in the treatment of infection especially with the formation of biofilm. Thus, it is essential to develop antimicrobials. Here we synthesized a novel small-molecule compound, which we termed SYG-180-2-2 (C21H16N2OSe), that had antibiofilm activity. The aim of this study was to demonstrate the antibiofilm effect of SYG-180-2-2 against clinical MRSA isolates at a subinhibitory concentration (4 μg/ml). In this study, it was showed that significant suppression in biofilm formation occurred with SYG-180-2-2 treatment, the inhibition ranged between 65.0 and 85.2%. Subsequently, confocal laser scanning microscopy and a bacterial biofilm metabolism activity assay further demonstrated that SYG-180-2-2 could suppress biofilm. Additionally, SYG-180-2-2 reduced bacterial adhesion and polysaccharide intercellular adhesin (PIA) production. It was found that the expression of icaA and other biofilm-related genes were downregulated as evaluated by RT-qPCR. At the same time, icaR and codY were upregulated when biofilms were treated with SYG-180-2-2. Based on the above results, we speculate that SYG-180-2-2 inhibits the formation of biofilm by affecting cell adhesion and the expression of genes related to PIA production. Above all, SYG-180-2-2 had no toxic effects on human normal alveolar epithelial cells BEAS-2B. Collectively, the small-molecule compound SYG-180-2-2 is a safe and effective antibacterial agent for inhibiting MRSA biofilm.}, } @article {pmid35068839, year = {2021}, author = {Beegam, KS and Joseph, A and Singh, VPP}, title = {Evaluation of the Antimicrobial Efficacy of Elettaria cardamomum Oil, Trachyspermum ammi Oil and 5% Sodium Hypochlorite Against Enterococcus faecalis Biofilm Formed on Tooth Substrate.}, journal = {Contemporary clinical dentistry}, volume = {12}, number = {4}, pages = {396-400}, pmid = {35068839}, issn = {0976-237X}, abstract = {CONTEXT: The usual cause of nonfulfillment of endodontic therapy is the persistence of microorganisms in the root canal system due to ineffective disinfection. Enterococcus faecalis is one of the most prevalently isolated microorganisms following a failure in root canal treatments. Sodium hypochlorite is among the most effectively used irrigant solutions but has many shortcomings. Herbal alternatives for sodium hypochlorite might prove to be superior due to their high antimicrobial activity, biocompatibility, and their antioxidant and anti-inflammatory properties.

AIMS: This study is aimed to evaluate the antimicrobial efficacy of Trachyspermum ammi oil and Elettaria cardamomum oil against 2-week-old and 4-week-old E. faecalis biofilms formed on tooth substrate.

SETTINGS AND DESIGN: A pure culture of E. faecalis was grown on brain heart infusion agar, inoculated into brain heart infusion broth, and incubated at 37°C overnight. Single rooted human mandibular premolars were sectioned below cementoenamel junction, enlarged, and vertically sectioned along the midsagittal plane. The samples were then placed in tissue culture wells inoculated with 2 ml of the bacterial solution and incubated at 37°C.

MATERIALS AND METHODS: Group 1 E. cardamomum oil (cardamom), Group 2 T. ammi oil (ajwain), Group 3 5% sodium hypochlorite, and Group 4 Saline (control) (n = 10). At the end of the 2[nd] and 4[th] weeks, all groups were treated for 10 min with 3 ml of the respective solutions. Quantitative analysis was performed by serial dilution.

RESULTS: T. ammi oil and sodium hypochlorite treated teeth showed complete elimination of both the 2-week-old and 4-week-old E. faecalis biofilm. Meanwhile, saline and E. cardamomum oil-treated teeth still showed the presence of E. faecalis.

CONCLUSIONS: The use of T. ammi oil as a root canal irrigant solution can be considered as an alternative to sodium hypochlorite.}, } @article {pmid35068601, year = {2022}, author = {Kaari, M and Joseph, J and Manikkam, R and Sreenivasan, A and Venugopal, G and Alexander, B and Krishnan, S}, title = {Anti-Biofilm Activity and Biocontrol Potential of Streptomyces Cultures Against Ralstonia solanacearum on Tomato Plants.}, journal = {Indian journal of microbiology}, volume = {62}, number = {1}, pages = {32-39}, pmid = {35068601}, issn = {0046-8991}, abstract = {Biological control of phytopathogen is a promising approach when compared to the use of chemical agents. In the present study, seven Streptomyces cultures showing promising anti biofilm activity against Ralstonia solanacearum was mixed individually with farmyard manure. All the Streptomyces fortified farmyard manure (SFYM) were screened for plant growth promotion and control of bacterial wilt caused by R. solanacearum on tomato. Further, the ability of SFYM on stimulating the production of defense-related enzymes in R. solanacearum-inoculated tomato plants was investigated. When compared to the control tomato plants, the SFYM-treated plants had longer shoot and root length along with higher fresh and dry weight. The maximum level of chlorophyll was observed in the plants treated with strain UP1A-1 (2.21 ± 0.18 mg g[-1]). Strain UP1A-1 also showed maximum of 96.8 ± 1.4% biocontrol efficacy in tomato plants challenged with R. solanacearum. In addition, the UP1A-1 treated tomato plants showed maximum accumulation of total phenolics (3.02 ± 0.09 mg g[-1]) after 6 days of pathogen inoculation (DPI). Similarly, tomato plants treated with UP1A-1 showed highest level of peroxides, polyphenol oxidase and phenylalanine ammonia lyase during 1-9 DPI. Findings of present study revealed that the Streptomyces culture UP1A-1 fortified farm yard manure could be applied as an eco-friendly alternative to synthetic agents for controlling bacterial wilt in tomato plants.}, } @article {pmid35067121, year = {2022}, author = {Aflakian, F and Rad, M and Hashemitabar, G and Lagzian, M and Ramezani, M}, title = {Design and assessment of novel synthetic peptides to inhibit quorum sensing-dependent biofilm formation in Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {38}, number = {2}, pages = {131-146}, doi = {10.1080/08927014.2022.2028280}, pmid = {35067121}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Peptides/pharmacology ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Pseudomonas aeruginosa is one of the most common biofilm-producing bacteria, often leading to long-term and chronic infections. The LasR regulator protein acts as the central regulator of the quorum sensing (QS) system and coordinates the expression of some virulence and biofilm genes. In this study, novel peptides (WSF, FASK, YDVD) were designed for binding to the domain of the transcriptional activator of the LasR protein and interfere with LasR in the QS system of P. aeruginosa. The effects of these peptides on biofilm production, expression of biofilm-related genes (AlgC, PslA, PelA), and growth of planktonic P. aeruginosa were investigated. All three peptides inhibited the growth of P. aeruginosa planktonic cells at 1600 µg ml[-1] and exhibited anti-biofilm effects at sub-inhibitory concentrations (800 µg ml[-1]). Measurements of the mRNA levels of biofilm-related genes at sub-inhibitory concentrations of the designed peptides showed a significant decrease.}, } @article {pmid35066687, year = {2022}, author = {Ardizzoni, A and Boaretto, G and Pericolini, E and Pinetti, D and Capezzone de Joannon, A and Durando, L and Ragni, L and Blasi, E}, title = {Effects of benzydamine and mouthwashes containing benzydamine on Candida albicans adhesion, biofilm formation, regrowth, and persistence.}, journal = {Clinical oral investigations}, volume = {26}, number = {4}, pages = {3613-3625}, pmid = {35066687}, issn = {1436-3771}, mesh = {*Benzydamine/pharmacology ; Biofilms ; *Candida albicans ; Mouthwashes/pharmacology ; Streptococcus mutans ; }, abstract = {OBJECTIVES: To assess the effects of benzydamine and mouthwashes (MoWs) containing benzydamine on different stages of Candida albicans biofilm: adhesion, formation, persistence, and regrowth (if perturbed).

MATERIALS AND METHODS: C. albicans CA1398, carrying the bioluminescence ACT1p-gLUC59 fusion product, was employed. Fungal cells were exposed for 1', 5', or 15' to 4 different benzydamine concentrations (0.075 to 0.6%) to 2 mouthwashes (MoWs) containing benzydamine and to a placebo MoW (without benzydamine). Treated cells were tested for adhesion (90 min) and biofilm formation (24-h assay). Next, 24- and 48-h-old biofilms were exposed to benzydamine and MoWs to assess regrowth and persistence, respectively. The effects of benzydamine, MoWs containing benzydamine, and placebo on different biofilm stages were quantified by bioluminescence assay and by the production of quorum sensing (QS) molecules.

RESULTS: Benzydamine and MoWs containing benzydamine impaired C. albicans ability to adhere and form biofilm, counteracted C. albicans persistence and regrowth, and impaired a 48-h-old biofilm. Some of these effects paralleled with alterations in QS molecule secretion.

CONCLUSIONS: Our results show for the first time that benzydamine and MoWs containing benzydamine impair C. albicans capacity to form biofilm and counteract biofilm persistence and regrowth.

CLINICAL RELEVANCE: Benzydamine and MoWs containing benzydamine capacity to affect C. albicans biofilm provides an interesting tool to prevent and treat oral candidiasis. Likely, restraining C. albicans colonization through daily oral hygiene may counteract colonization and persistence by other critical oral pathogens, such as Streptococcus mutans, whose increased virulence has been linked to the presence of C. albicans biofilm.}, } @article {pmid35066679, year = {2022}, author = {Liang, Y and Pan, Y and Li, Q and Wu, B and Hu, M}, title = {RNA-seq-based transcriptomic analysis of AHL-induced biofilm and pyocyanin inhibition in Pseudomonas aeruginosa by Lactobacillus brevis.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {3}, pages = {447-456}, pmid = {35066679}, issn = {1618-1905}, support = {42077395//national natural science foundation of china/ ; Y03019023601008022//university of electronic science and technology of china/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; *Levilactobacillus brevis/genetics/metabolism ; *Pseudomonas aeruginosa ; Pyocyanine/metabolism/pharmacology ; Quorum Sensing/genetics ; RNA-Seq ; Transcriptome ; }, abstract = {Quorum sensing (QS) regulates hundreds of genes in Pseudomonas aeruginosa, and many of which encode extracellular virulence factors. Lactobacillus as a probiotic has been verified to inhibit pathogenesis in P. aeruginosa via quenching QS. The objective of this study was to investigate mechanism of the QS quenching function of Lactobacillus via analyzing the gene expression by transcriptome. We previously isolated a Lactobacillus brevis strain 3M004 from an aquafeed and identified the strain has the function of degrading QS molecular AHL (OC12-HSL). The result showed that 3M004 cells/lysate inhibited biofilm and pyocyanin production of P. aeruginosa PA002. The biofilm inhibition rates were 16.92% and 33.0% after treatment by 1 and 2 mg/mL 3M004 lysate, respectively, and the rates for pyocyanin inhibition were 25.16% and 30.75%, respectively. Transcriptomic analysis showed that down-regulation of genes of LasA and LasB in PA002 was essential in regulating the QS system. The biofilm decrease of PA002 seems not only resulted from gene biosynthesizing of polysaccharides but also from other genes regulating components biosynthesis. Pyocyanin biosynthesis appears to be inhibited by down-regulating the key gene of PhzAB on the nonreversing action from chorismite to pyocyanin.}, } @article {pmid35065252, year = {2022}, author = {Garousi, M and Monazami Tabar, S and Mirazi, H and Asgari, P and Sabeghi, P and Salehi, A and Khaledi, A and Ghenaat Pisheh Sanani, M and Mirzahosseini, HK}, title = {A global systematic review and meta-analysis on correlation between biofilm producers and non-biofilm producers with antibiotic resistance in Uropathogenic Escherichiacoli.}, journal = {Microbial pathogenesis}, volume = {164}, number = {}, pages = {105412}, doi = {10.1016/j.micpath.2022.105412}, pmid = {35065252}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Drug Resistance, Microbial ; *Escherichia coli Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; *Urinary Tract Infections/microbiology ; *Uropathogenic Escherichia coli ; }, abstract = {Escherichia coli accounts for nearly 80% of community-acquired and 50% of hospital-acquired urinary tract infections (UTI). This study aimed to evaluate the correlation between biofilm producers and Non-biofilm producers with antibiotic resistance in Uropathogenic Escherichia coli (UPEC) isolated from patients with UTI globally. The search was conducted between 1st 2000 to 30[th] October 2021 in various databases (PubMed, Scopus, Web of sciences, and Google Scholar) with suitable MeSH terms, and text words. Then, after applying the appropriate inclusion and exclusion criteria on the studies for their selection, the data were analyzed by CMA software. Thirty-seven studies met the eligibility criteria to include. The pooled prevalence of ESBL and MDR isolates were reported 37.9%, and 65.8%, respectively. Biofilm formation varied between 13.3% and 99% all over the world. A total of 74.4% of all isolates were biofilm producers, out of which 28.6%, 35.2%, and 38.6% showed strong, moderate, and weak biofilm. The highest and lowest resistance was against Amoxicillin and Meropenem with the prevalence of 80.8%, and 13%, respectively. Fourteen out of 17(82.35%) studies reported a positive correlation between biofilm and antibiotic resistance. Findings showed high numbers of isolates were able to form biofilm, which is one of the factors of antibiotic resistance, and this has been confirmed by the positive significant correlation between biofilm formation and antibiotic resistance that has been reported by studies included. Therefore, due to the importance of biofilm in the etiology of UTI caused by UPEC, it should be prevented; consequently, bacterial resistance can be reduced and controlled.}, } @article {pmid35065112, year = {2022}, author = {Wu, C and Tanaka, K and Tani, Y and Bi, X and Liu, J and Yu, Q}, title = {Effect of particle size on the colonization of biofilms and the potential of biofilm-covered microplastics as metal carriers.}, journal = {The Science of the total environment}, volume = {821}, number = {}, pages = {153265}, doi = {10.1016/j.scitotenv.2022.153265}, pmid = {35065112}, issn = {1879-1026}, mesh = {Biofilms ; *Metals, Heavy ; *Microplastics/toxicity ; Particle Size ; Plastics/chemistry ; }, abstract = {Upon release into the aquatic environment, the surface of microplastics (MPs) can be readily colonized by biofilms, which may enhance the adsorption of contaminants. In this study, industrial-grade polystyrene (PS) of about 4 mm in size (MP4000-1), food-grade PS of about 4 mm in size (MP4000-2), and Powder PS of about 75 μm in size (MP75) were co-cultured with a model freshwater fungus, namely Acremonium strictum strain KR21-2, for seven days to form biofilms on their surface. We also determined the changes in surface physicochemical properties of the biofilm-covered MPs (BMPs) and the heavy metal adsorption capacity of the original MPs and BMPs. The results revealed that the biofilms improve the adsorption of heavy metals on MPs, and the particle size of MPs plays a crucial role in biofilm colonization and adsorption of heavy metals by BMPs. MP75 can carry more biofilm on its surface than that of the two MP4000s and form heteroaggregates with biofilms. In addition, there were more functional groups on the surface of BMP75 than on the surface of the two BMP4000s, which could promote the electrostatic interaction and chemical association of heavy metals. Moreover, BMP75 exhibited a higher capacity to adsorb Cu and reduce Cr (VI), which may be related to the functional groups in its biofilm. Overall, this study showed that after biofilms colonization, BMPs of smaller size have more significant potential as a metal vector, and the particle size deserves more scientific attention during the risk assessment.}, } @article {pmid35064842, year = {2022}, author = {Vijayakumar, K and Muhilvannan, S and Arun Vignesh, M}, title = {Hesperidin inhibits biofilm formation, virulence and staphyloxanthin synthesis in methicillin resistant Staphylococcus aureus by targeting SarA and CrtM: an in vitro and in silico approach.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {3}, pages = {44}, pmid = {35064842}, issn = {1573-0972}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/chemistry/*metabolism ; Biofilms/*drug effects ; Farnesyl-Diphosphate Farnesyltransferase/chemistry/*metabolism ; Gene Expression Regulation, Bacterial ; Hesperidin/chemistry/*pharmacology ; Humans ; Methicillin-Resistant Staphylococcus aureus/chemistry/*drug effects/*physiology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Staphylococcal Infections/drug therapy/microbiology ; Trans-Activators/chemistry/*metabolism ; Virulence/drug effects ; Virulence Factors/metabolism ; Xanthophylls/*metabolism ; }, abstract = {Methicillin resistant Staphylococcus aureus is considered multidrug resistant bacterium due to developing biofilm formation associated with antimicrobial resistance mechanisms. Therefore, inhibition of biofilm formation is an alternative therapeutic action to control MRSA infections. The present study revealed the non-antibacterial biofilm inhibitory potential of hesperidin against ATCC strain and clinical isolates of S. aureus. Hesperidin is a flavanone glycoside commonly found in citrus fruit. Hesperidin has been shown to exhibits numerous pharmacological activities. The present study aimed to evaluate the antibiofilm and antivirulence potential of hesperidin against MRSA. Results showed that hesperidin treatment significantly impedes lipase, hemolysin, autolysin, autoaggregation and staphyloxanthin production. Reductions of staphyloxanthin production possibly increase the MRSA susceptibility rate to H2O2 oxidative stress condition. In gene expression study revealed that hesperidin treatment downregulated the biofilm-associated gene (sarA), polysaccharide intracellular adhesion gene (icaA and icaD), autolysin (altA), fibronectin-binding protein (fnbA and fnbB) and staphyloxanthin production (crtM). Molecular docking analysis predicted the ability of hesperidin to interact with SarA and CrtM proteins involved in biofilm formation and staphyloxanthin production in MRSA.}, } @article {pmid35064407, year = {2022}, author = {Tabandeh, M and Kaboosi, H and Taghizadeh Armaki, M and Pournajaf, A and Peyravii Ghadikolaii, F}, title = {New update on molecular diversity of clinical Staphylococcus aureus isolates in Iran: antimicrobial resistance, adhesion and virulence factors, biofilm formation and SCCmec typing.}, journal = {Molecular biology reports}, volume = {49}, number = {4}, pages = {3099-3111}, pmid = {35064407}, issn = {1573-4978}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cross-Sectional Studies ; Drug Resistance, Bacterial/genetics ; Humans ; Iran/epidemiology ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Molecular Typing ; *Staphylococcal Infections/epidemiology/microbiology ; Staphylococcus aureus/genetics ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Staphylococcus aureus is often considered as a potential pathogen and resistant to a wide range of antibiotics. The pathogenicity of this bacterium is due to the presence of multiple virulence factors and the ability to form biofilm. SCCmec types I, II and III are mainly attributed to HA-MRSA, while SCCmec types IV and V have usually been reported in CA-MRSA infections.

METHODS AND RESULTS: In this study, we performed a cross-sectional study to determine the antimicrobial resistance, adhesion and virulence factors, biofilm formation and SCCmec typing of clinical S. aureus isolates in Iran. S. aureus isolates were identified using microbiological standard methods and antibiotic susceptibility tests were performed as described by the Clinical and Laboratory Standards Institute (CLSI) guidelines. Inducible resistance phenotype and biofilm formation were determined using D-test and tissue culture plate methods, respectively. Multiplex-PCRs were performed to detect adhesion and virulence factors, antibiotic resistance genes, biofilm formation and SCCmec typing by specific primers. Among 143 clinical samples, 67.8% were identified as MRSA. All isolates were susceptible to vancomycin. The prevalence of cMLSB, iMLSB and MS phenotypes were 61.1%, 22.2% and 14.8%, respectively. The TCP method revealed that 71.3% of isolates were able to form biofilm. The predominant virulence and inducible resistance genes in both MRSA and MSSA isolates were related to sea and ermC respectively. SCCmec type III was the predominant type.

CONCLUSIONS: Data show the high prevalence rates of virulence elements among S. aureus isolates, especially MRSA strains. This result might be attributed to antibiotic pressure, facilitating clonal selection.}, } @article {pmid35063652, year = {2022}, author = {Weiler, AJ and Spitz, O and Gudzuhn, M and Schott-Verdugo, SN and Kamel, M and Thiele, B and Streit, WR and Kedrov, A and Schmitt, L and Gohlke, H and Kovacic, F}, title = {A phospholipase B from Pseudomonas aeruginosa with activity towards endogenous phospholipids affects biofilm assembly.}, journal = {Biochimica et biophysica acta. Molecular and cell biology of lipids}, volume = {1867}, number = {4}, pages = {159101}, doi = {10.1016/j.bbalip.2021.159101}, pmid = {35063652}, issn = {1879-2618}, mesh = {Biofilms ; Detergents/pharmacology ; Escherichia coli/genetics/metabolism ; *Lysophospholipase/metabolism ; Phospholipases/genetics/metabolism ; Phospholipids/metabolism ; *Pseudomonas aeruginosa ; Virulence Factors/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa is a severe threat to immunocompromised patients due to its numerous virulence factors and biofilm-mediated multidrug resistance. It produces and secretes various toxins with hydrolytic activities including phospholipases. However, the function of intracellular phospholipases for bacterial virulence has still not been established. Here, we demonstrate that the hypothetical gene pa2927 of P. aeruginosa encodes a novel phospholipase B named PaPlaB. At reaction equilibrium, PaPlaB purified from detergent-solubilized membranes of E. coli released fatty acids (FAs) from sn-1 and sn-2 positions of phospholipids at the molar ratio of 51:49. PaPlaB in vitro hydrolyzed P. aeruginosa phospholipids reconstituted in detergent micelles and phospholipids reconstituted in vesicles. Cellular localization studies indicate that PaPlaB is a cell-bound PLA of P. aeruginosa and that it is peripherally bound to both membranes in E. coli, yet the active form was predominantly associated with the cytoplasmic membrane of E. coli. Decreasing the concentration of purified and detergent-stabilized PaPlaB leads to increased enzymatic activity, and at the same time triggers oligomer dissociation. We showed that the free FA profile, biofilm amount and architecture of the wild type and ΔplaB differ. However, it remains to be established how the PLB activity of PaPlaB is regulated by homooligomerisation and how it relates to the phenotype of the P. aeruginosa ΔplaB. This novel putative virulence factor contributes to our understanding of phospholipid degrading enzymes and might provide a target for new therapeutics against P. aeruginosa biofilms.}, } @article {pmid35063624, year = {2022}, author = {Zhang, W and Yu, D and Zhang, J and Miao, Y and Zhao, X and Ma, G and Li, J and Zhang, Y}, title = {Start-up of mainstream anammox process through inoculating nitrification sludge and anammox biofilm: Shift in nitrogen transformation and microorganisms.}, journal = {Bioresource technology}, volume = {347}, number = {}, pages = {126728}, doi = {10.1016/j.biortech.2022.126728}, pmid = {35063624}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Denitrification ; *Nitrification ; Nitrogen ; Oxidation-Reduction ; Sewage ; Wastewater ; }, abstract = {The feasibility of starting up mainstream single-stage partial nitrification-anammox (SPNA) system by inoculating nitrification sludge and anammox biofilm was investigated. The SPNA system treating low-strength synthetic wastewater was rapidly started up with TN removal efficiency of 88.5 ± 1.8% and effluent nitrate concentration of 7.2 ± 1.2 mg/L. Both the abundance and maximum activity of nitrite oxidizing bacteria (NOB) in flocs decreased obviously. Interestingly, the abundance of anaerobic ammonium oxidizing bacteria (AnAOB) in flocs increased from 0.213% to 0.346% despite the sludge retention time (SRT) of flocs decreased to 60 days, the AnAOB in biofilm was 0.434%. That meant AnAOB gradually enriched in flocs and accounted for a fairly high proportion. The inhibition of NOB, partial denitrification and increased aerobic_chemoheterotrophy function in flocs might be the main reasons for AnAOB enrichment. The possibility of simultaneous fermentation, partial denitrification and anammox reaction was predicted in biofilm, further improving the stability of the system.}, } @article {pmid35061929, year = {2022}, author = {Cheah, YT and Chan, DJC}, title = {A methodological review on the characterization of microalgal biofilm and its extracellular polymeric substances.}, journal = {Journal of applied microbiology}, volume = {132}, number = {5}, pages = {3490-3514}, doi = {10.1111/jam.15455}, pmid = {35061929}, issn = {1365-2672}, support = {//Ministry of Higher Education/ ; }, mesh = {Biofilms ; *Extracellular Polymeric Substance Matrix/metabolism ; *Microalgae/metabolism ; }, abstract = {Biofilm secreted by microalgae are extracellular polymeric substances (EPSs) composed mainly of polysaccharides, proteins, nucleic acids and lipids. These EPSs immobilize the cells and stabilize biofilm, mediating adhesion towards solid surfaces. The EPSs valorization through industrial exploitations and scientific works is becoming more popular, but the bottleneck of such studies is the lack of consensus among researchers on the selection of detection techniques to be used, especially for novice researchers. It is a daunting task for any inexperienced researcher when they fail to identify the right tools needed for microalgal biofilm studies. In this review, a well-refined analysis protocol about microalgal biofilm and EPSs were prepared including its extraction and characterization. Pros and cons of various detection techniques were addressed and cutting-edge methods to study biofilm EPSs were highlighted. Future perspectives were also presented at the end of this review to bridge research gaps in studying biofilm adhesion via EPSs production. Ultimately, this review aims to assist novice researchers in making the right choices in their research studies on microalgal biofilms in accordance to the available technologies and needs.}, } @article {pmid35058896, year = {2021}, author = {Wang, Y and Wang, M and Xu, W and Wang, Y and Zhang, Y and Wang, J}, title = {Estimating the Postmortem Interval of Carcasses in the Water Using the Carrion Insect, Brain Tissue RNA, Bacterial Biofilm, and Algae.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {774276}, pmid = {35058896}, issn = {1664-302X}, abstract = {The accurate estimation of postmortem interval (PMI) is crucial in the investigation of homicide cases. Unlike carcasses on land, various biological and abiotic factors affect the decomposition of carcasses in water. In addition, the insect evidence (e.g., blow flies) that is commonly used to estimate the PMI are unavailable before the carcasses float on water. Therefore, it is difficult to estimate the PMI of a carcass in water. This study aimed to explore an effective way of estimating the PMI of a carcass in water. Carrion insects, brain tissue RNA, bacterial biofilm on the skin surface, and algae in water with PMI were studied using 45 rat carcasses in a small river. The results showed that carrion insects might not be suitable for the estimation of PMI of a carcass in water since they do not have a regular succession pattern as a carcass on land, and the flies only colonized six of the carcasses. The target genes (β-actin, GAPDH, and 18S) in the brain tissue were associated with the PMI in a time-dependent manner within 1 week after death. A polynomial regression analysis was used to assess the relationship between the gene expression profiles and PMI. The correlation coefficient R [2] of each regression equation was ≥ 0.924. A third-generation sequencing analysis showed that the bacteria on the skin surface of the carcass and the algae in the water samples around the carcass had a regular succession pattern, where Cryptomonas and Placoneis incased and decreased, respectively, within first 9 days. The results of this study provide a promising way to use the brain tissue RNA, bacterial biofilm, and algae to estimate the PMI of a carcass in water.}, } @article {pmid35057785, year = {2022}, author = {Seguya, A and Mowafy, M and Gaballah, A and Zaher, A}, title = {Chlorhexidine versus organoselenium for inhibition of S. mutans biofilm, an in vitro study.}, journal = {BMC oral health}, volume = {22}, number = {1}, pages = {14}, pmid = {35057785}, issn = {1472-6831}, mesh = {*Anti-Infective Agents, Local/pharmacology ; Biofilms ; Chlorhexidine/pharmacology ; Colony Count, Microbial ; *Dental Caries/prevention & control ; *Dental Plaque/prevention & control ; Humans ; Streptococcus mutans ; }, abstract = {BACKGROUND: Chemical Plaque control by antimicrobial agent application can defend the teeth against caries. S. mutans is considered the main etiologic factor for caries. This was an in vitro study to compare between the efficacy of chlorhexidine diaceteate varnish, and an organoselenium sealant, to prevent S. mutans biofilm formation on human teeth.

METHODS: Fourty five premolars extracted for orthodontic purposes were randomly divided into 3 groups of 15 teeth each. One control group and two test groups, chlorhexidine diaceteate varnish and an organoselenium sealant. The teeth were autoclaved before S. mutans biofilm was induced on to each in their respective groups. The reading T1 was taken for each tooth to assess the number of S. mutans attached in order to compare for differences in surface area among the 3 groups. The respective test materials were applied onto the teeth and biofilm induced onto them in their respective groups. The reading T2 was taken for the 2 test groups. The 3 groups were then subjected to aging for a period equivalent to 5 months before the biofilm was induced to take the reading T3 for the number of S. mutans. We used vortexing of the teeth to disrupt the biofilm at time points T1, T2 and T3. S. mutans count was then done using PCR.

RESULTS: There were significantly lower S. mutans counts in the control group as compared to the chlorhexidine diacetate group at T3.There were no other statistically significant differences found.

CONCLUSION: Both organoselenium and Chlorhexidine diacetate do not inhibit S. mutans biofilm attachment onto the teeth.}, } @article {pmid35056612, year = {2022}, author = {Panebianco, F and Rubiola, S and Di Ciccio, PA}, title = {The Use of Ozone as an Eco-Friendly Strategy against Microbial Biofilm in Dairy Manufacturing Plants: A Review.}, journal = {Microorganisms}, volume = {10}, number = {1}, pages = {}, pmid = {35056612}, issn = {2076-2607}, abstract = {Managing spoilage and pathogenic bacteria contaminations represents a major challenge for the food industry, especially for the dairy sector. Biofilms formed by these microorganisms in food processing environment continue to pose concerns to food manufacturers as they may impact both the safety and quality of processed foods. Bacteria inside biofilm can survive in harsh environmental conditions and represent a source of repeated food contamination in dairy manufacturing plants. Among the novel approaches proposed to control biofilm in food processing plants, the ozone treatment, in aqueous or gaseous form, may represent one of the most promising techniques due to its antimicrobial action and low environmental impact. The antimicrobial effectiveness of ozone has been well documented on a wide variety of microorganisms in planktonic forms, whereas little data on the efficacy of ozone treatment against microbial biofilms are available. In addition, ozone is recognized as an eco-friendly technology since it does not leave harmful residuals in food products or on contact surfaces. Thus, this review intends to present an overview of the current state of knowledge on the possible use of ozone as an antimicrobial agent against the most common spoilage and pathogenic microorganisms, usually organized in biofilm, in dairy manufacturing plants.}, } @article {pmid35056610, year = {2022}, author = {Fernandes, S and Gomes, IB and Sousa, SF and Simões, M}, title = {Antimicrobial Susceptibility of Persister Biofilm Cells of Bacillus cereus and Pseudomonas fluorescens.}, journal = {Microorganisms}, volume = {10}, number = {1}, pages = {}, pmid = {35056610}, issn = {2076-2607}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219//Fundação para a Ciência e Tecnologia/ ; }, abstract = {The present study evaluates the antimicrobial susceptibility of persister cells of Bacillus cereus and Pseudomonas fluorescens after their regrowth in suspension and as biofilms. Two conventional (benzalkonium chloride-BAC and peracetic acid-PAA) and two emerging biocides (glycolic acid-GA and glyoxal-GO) were selected for this study. Persister cells resulted from biofilms subjected to a critical treatment using the selected biocides. All biocide treatments developed B. cereus persister cells, except PAA that effectively reduced the levels of vegetative cells and endospores. P. fluorescens persister cells comprise viable and viable but non-culturable cells. Afterwards, persister cells were regrown in suspension and in biofilms and were subjected to a second biocide treatment. In general, planktonic cultures of regrown persister cells in suspension lost their antimicrobial tolerance, for both bacteria. Regrown biofilms of persister cells had antimicrobial susceptibility close to those regrown biofilms of biocide-untreated cells, except for regrown biofilms of persister P. fluorescens after BAC treatment, which demonstrated increased antimicrobial tolerance. The most active biocide against persister cells was PAA, which did not promote changes in susceptibility after their regrowth. In conclusion, persister cells are ubiquitous within biofilms and survive after critical biocide treatment. The descendant planktonic and biofilms populations showed similar properties as the original ones.}, } @article {pmid35056128, year = {2022}, author = {Al-Ani, E and Heaselgrave, W}, title = {The Investigation of Thymol Formulations Containing Poloxamer 407 and Hydroxypropyl Methylcellulose to Inhibit Candida Biofilm Formation and Demonstrate Improved Bio-Compatibility.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {15}, number = {1}, pages = {}, pmid = {35056128}, issn = {1424-8247}, abstract = {The aim of this study was to investigate the potential of thymol to inhibit Candida biofilm formation and improve thymol biocompatibility in the presence of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), as possible drug carriers. Thymol with and without polymers were tested for its ability to inhibit biofilm formation, its effect on the viability of biofilm and biocompatibility studies were performed on HEK 293 (human embryonic kidney) cells. Thymol showed a concentration dependent biofilm inhibition; this effect was slightly improved when it was combined with HPMC. The Thymol-P407 combination completely inhibited the formation of biofilm and the antibiofilm effect of thymol decreased as the maturation of Candida biofilms increased. The effect of thymol on HEK 293 cells was a loss of nearly 100% in their viability at a concentration of 250 mg/L. However, in the presence of P407, the viability was 25% and 85% using neutral red uptake and sulforhodamine B assays, respectively. While, HPMC had less effect on thymol activity the thymol-P407 combination showed a superior inhibitory effect on biofilm formation and better biocompatibility with human cell lines. The combination demonstrates a potential medical use for the prevention of Candida biofilm formation.}, } @article {pmid35055990, year = {2021}, author = {Oleksy-Wawrzyniak, M and Junka, A and Brożyna, M and Paweł, M and Kwiek, B and Nowak, M and Mączyńska, B and Bartoszewicz, M}, title = {The In Vitro Ability of Klebsiella pneumoniae to Form Biofilm and the Potential of Various Compounds to Eradicate It from Urinary Catheters.}, journal = {Pathogens (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35055990}, issn = {2076-0817}, support = {STM.D230.16.038//Wroclaw Medical University/ ; SUB.D230.21.102//Wroclaw Medical University/ ; }, abstract = {Urinary infections related to the presence of bacterial biofilm on catheters are responsible for loss of patients' health and, due to their high frequency of occurrence, generate a significant economic burden for hospitals. Klebsiella pneumoniae is a pathogen frequently isolated from this type of infection. In this study, using a cohesive set of techniques performed under stationary and flow conditions, we assessed the ability of 120 K. pneumoniae strains to form biofilm on various surfaces, including catheters, and evaluated the usefulness of clinically applied and experimental compounds to remove biofilm. The results of our study indicate the high impact of intraspecies variability with respect to K. pneumoniae biofilm formation and its susceptibility to antimicrobials and revealed the crucial role of mechanical flushing out of the biofilm from the catheter's surface with use of locally active antimicrobials. Therefore, our work, although of in vitro character, may be considered an important step in the direction of efficient reduction of K. pneumoniae biofilm-related hospital infections associated with the presence of urine catheters.}, } @article {pmid35054915, year = {2022}, author = {Moshynets, OV and Baranovskyi, TP and Iungin, OS and Kysil, NP and Metelytsia, LO and Pokholenko, I and Potochilova, VV and Potters, G and Rudnieva, KL and Rymar, SY and Semenyuta, IV and Spiers, AJ and Tarasyuk, OP and Rogalsky, SP}, title = {eDNA Inactivation and Biofilm Inhibition by the PolymericBiocide Polyhexamethylene Guanidine Hydrochloride (PHMG-Cl).}, journal = {International journal of molecular sciences}, volume = {23}, number = {2}, pages = {}, pmid = {35054915}, issn = {1422-0067}, mesh = {Anti-Infective Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; DNA, Bacterial/chemistry/*drug effects ; Disinfectants/chemistry/*pharmacology ; Guanidines/chemical synthesis/chemistry/*pharmacology ; Nucleic Acid Conformation/drug effects ; Pseudomonas aeruginosa/drug effects/genetics ; Staphylococcus aureus/drug effects/genetics ; Structure-Activity Relationship ; }, abstract = {The choice of effective biocides used for routine hospital practice should consider the role of disinfectants in the maintenance and development of local resistome and how they might affect antibiotic resistance gene transfer within the hospital microbial population. Currently, there is little understanding of how different biocides contribute to eDNA release that may contribute to gene transfer and subsequent environmental retention. Here, we investigated how different biocides affect the release of eDNA from mature biofilms of two opportunistic model strains Pseudomonas aeruginosa ATCC 27853 (PA) and Staphylococcus aureus ATCC 25923 (SA) and contribute to the hospital resistome in the form of surface and water contaminants and dust particles. The effect of four groups of biocides, alcohols, hydrogen peroxide, quaternary ammonium compounds, and the polymeric biocide polyhexamethylene guanidine hydrochloride (PHMG-Cl), was evaluated using PA and SA biofilms. Most biocides, except for PHMG-Cl and 70% ethanol, caused substantial eDNA release, and PHMG-Cl was found to block biofilm development when used at concentrations of 0.5% and 0.1%. This might be associated with the formation of DNA-PHMG-Cl complexes as PHMG-Cl is predicted to bind to AT base pairs by molecular docking assays. PHMG-Cl was found to bind high-molecular DNA and plasmid DNA and continued to inactivate DNA on surfaces even after 4 weeks. PHMG-Cl also effectively inactivated biofilm-associated antibiotic resistance gene eDNA released by a pan-drug-resistant Klebsiella strain, which demonstrates the potential of a polymeric biocide as a new surface-active agent to combat the spread of antibiotic resistance in hospital settings.}, } @article {pmid35054522, year = {2022}, author = {Morozova, Y and Voborná, I and Žižka, R and Bogdanová, K and Večeřová, R and Rejman, D and Kolář, M and Do Pham, DD and Holík, P and Moštěk, R and Rosa, M and Pospíšilová, L}, title = {Ex Vivo Effect of Novel Lipophosphonoxins on Root Canal Biofilm Produced by Enterococcus faecalis: Pilot Study.}, journal = {Life (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {35054522}, issn = {2075-1729}, abstract = {(1) Background: The root canal system has complex anatomical and histological features that make it impossible to completely remove all bacteria by mechanical means only; they must be supplemented with disinfectant irrigation. Current disinfectants are unable to eliminate certain microorganisms that persist in the root canal, resulting in treatment failure. At the Institute of Organic Chemistry and Biochemistry, Prague, novel substances with the bactericidal effect, termed lipophosphonoxins (LPPOs), have been discovered. The aim of this pilot study was to investigate the ex vivo effects of second- and third-generation LPPOs on Enterococcus faecalis and compare them with 5% sodium hypochlorite (NaOCl), 0.12% chlorhexidine digluconate, and 17% ethylenediaminetetraacetic acid (EDTA). (2) Methods: The root canal's dentin was used as a carrier for biofilm formation in the extracted human mature mandibular premolars. The samples were filled with cultivation broth and 0.25% glucose with tested solutions. In control samples, only fresh cultivation broth (negative control) and cultivation broth with bacterial suspension (growth control) were used. Each sample was inoculated with E. faecalis CCM4224 except for the negative control, and cultivation was performed. To determine the number of planktonic cells, the sample content was inoculated on blood agar. To evaluate biofilm formation inhibition, samples were placed in tubes with BHI. (3) Results: LPPOs exhibited a reduction in biofilm growth and bacteria comparable to NaOCl, and they were superior to other tested disinfectants. (4) Conclusions: The study results suggest the effect of lipophosphonoxins on E. faecalis CCM 4224 reduces planktonic bacterial cells and inhibits formation of biofilm in root canal samples.}, } @article {pmid35053246, year = {2022}, author = {Sycz, Z and Tichaczek-Goska, D and Wojnicz, D}, title = {Anti-Planktonic and Anti-Biofilm Properties of Pentacyclic Triterpenes-Asiatic Acid and Ursolic Acid as Promising Antibacterial Future Pharmaceuticals.}, journal = {Biomolecules}, volume = {12}, number = {1}, pages = {}, pmid = {35053246}, issn = {2218-273X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Humans ; Pentacyclic Triterpenes/chemistry/pharmacology ; Pharmaceutical Preparations ; *Plankton ; Triterpenes ; }, abstract = {Due to the ever-increasing number of multidrug-resistant bacteria, research concerning plant-derived compounds with antimicrobial mechanisms of action has been conducted. Pentacyclic triterpenes, which have a broad spectrum of medicinal properties, are one of such groups. Asiatic acid (AA) and ursolic acid (UA), which belong to this group, exhibit diverse biological activities that include antioxidant, anti-inflammatory, diuretic, and immunostimulatory. Some of these articles usually contain only a short section describing the antibacterial effects of AA or UA. Therefore, our review article aims to provide the reader with a broader understanding of the activity of these acids against pathogenic bacteria. The bacteria in the human body can live in the planktonic form and create a biofilm structure. Therefore, we found it valuable to present the action of AA and UA on both planktonic and biofilm cultures. The article also presents mechanisms of the biological activity of these substances against microorganisms.}, } @article {pmid35052990, year = {2022}, author = {Brown, JL and Young, T and McKloud, E and Butcher, MC and Bradshaw, D and Pratten, JR and Ramage, G}, title = {An In Vitro Evaluation of Denture Cleansing Regimens against a Polymicrobial Denture Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052990}, issn = {2079-6382}, support = {0//GlaxoSmithKline/ ; BB/V509541/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Denture stomatitis (DS) is an inflammatory disease resulting from a polymicrobial biofilm perturbation at the denture surface-palatal mucosa interface. Recommendations made by dental health care professionals often lack clarity for appropriate denture cleaning. This study investigated the efficacy of brushing with off-the-shelf denture cleanser (DC) tablets (Poligrip[®]) vs. two toothpastes (Colgate[®] and Crest[®]) in alleviating the viable microorganisms (bacteria and fungi) in an in vitro denture biofilm model. Biofilms were grown on poly(methyl)methacrylate (PMMA) discs, then treated daily for 7 days with mechanical disruption (brushing), plus Poligrip[®] DC, Colgate[®] or Crest[®] toothpastes. Weekly treatment with Poligrip[®] DC on day 7 only was compared to daily modalities. All treatment parameters were processed to determine viable colony forming units for bacteria and fungi using the Miles and Misra technique, and imaged by confocal laser scanning microscopy (CLSM). Brushing with daily DC therapy was the most effective treatment in reducing the viable biofilm over 7 days of treatment. Brushing only was ineffective in controlling the viable bioburden, which was confirmed by CLSM imaging. This data indicates that regular cleansing of PMMA with DC was best for polymicrobial biofilms.}, } @article {pmid35052964, year = {2022}, author = {Švarcová, K and Pejchalová, M and Šilha, D}, title = {The Effect of Antibiotics on Planktonic Cells and Biofilm Formation Ability of Collected Arcobacter-like Strains and Strains Isolated within the Czech Republic.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052964}, issn = {2079-6382}, abstract = {The purpose of this study was to test the in vitro effects of ampicillin, ciprofloxacin, clindamycin, erythromycin, gentamicin, and tetracycline on planktonic cells of Arcobacter-like microorganisms and on their biofilm formation ability. The minimum inhibitory concentrations (MICs) were determined by the microdilution method. Further, biofilm formation ability in the presence of various concentrations of antibiotics was evaluated by a modified Christensen method. Most of the 60 strains exhibited high susceptibility to gentamicin (98.3%), ciprofloxacin (95.0%), and erythromycin (100.0%). High level of resistance was observed to clindamycin and tetracycline with MIC50 and MIC90 in range of 4-32 mg/L and 32-128 mg/L, respectively. Combined resistance to both clindamycin and tetracycline was found in 38.3% of tested strains. In general, higher biofilm formation was observed especially at lower concentrations of antibiotics (0.13-2 mg/L). However, a significant decrease in biofilm formation ability of Pseudarcobacter defluvii LMG 25694 was exhibited with ampicillin and clindamycin at concentrations above 32 or 8 mg/L, respectively. Biofilm formation represents a potential danger of infection and also a risk to human health, in particular due to antimicrobial-resistant strains and the ability to form a biofilm structure at a concentration that is approximately the MIC determined for planktonic cells.}, } @article {pmid35052956, year = {2022}, author = {Qureshi, KA and Imtiaz, M and Parvez, A and Rai, PK and Jaremko, M and Emwas, AH and Bholay, AD and Fatmi, MQ}, title = {In Vitro and In Silico Approaches for the Evaluation of Antimicrobial Activity, Time-Kill Kinetics, and Anti-Biofilm Potential of Thymoquinone (2-Methyl-5-propan-2-ylcyclohexa-2,5-diene-1,4-dione) against Selected Human Pathogens.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052956}, issn = {2079-6382}, support = {PHUC-2021-FTF-078//Qassim University/ ; }, abstract = {Thymoquinone (2-methyl-5-propan-2-ylcyclohexa-2,5-diene-1,4-dione; TQ), a principal bioactive phytoconstituent of Nigella sativa essential oil, has been reported to have high antimicrobial potential. Thus, the current study evaluated TQ's antimicrobial potential against a range of selected human pathogens using in vitro assays, including time-kill kinetics and anti-biofilm activity. In silico molecular docking of TQ against several antimicrobial target proteins and a detailed intermolecular interaction analysis was performed, including binding energies and docking feasibility. Of the tested bacteria and fungi, S. epidermidis ATCC 12228 and Candida albicans ATCC 10231 were the most susceptible to TQ, with 50.3 ± 0.3 mm and 21.1 ± 0.1 mm zones of inhibition, respectively. Minimum inhibitory concentration (MIC) values of TQ are in the range of 12.5-50 µg/mL, while minimum biocidal concentration (MBC) values are in the range of 25-100 µg/mL against the tested organisms. Time-kill kinetics of TQ revealed that the killing time for the tested bacteria is in the range of 1-6 h with the MBC of TQ. Anti-biofilm activity results demonstrate that the minimum biofilm inhibitory concentration (MBIC) values of TQ are in the range of 25-50 µg/mL, while the minimum biofilm eradication concentration (MBEC) values are in the range of 25-100 µg/mL, for the tested bacteria. In silico molecular docking studies revealed four preferred antibacterial and antifungal target proteins for TQ: D-alanyl-D-alanine synthetase (Ddl) from Thermus thermophilus, transcriptional regulator qacR from Staphylococcus aureus, N-myristoyltransferase from Candida albicans, and NADPH-dependent D-xylose reductase from Candida tenuis. In contrast, the nitroreductase family protein from Bacillus cereus and spore coat polysaccharide biosynthesis protein from Bacillus subtilis and UDP-N-acetylglucosamine pyrophosphorylase from Aspergillus fumigatus are the least preferred antibacterial and antifungal target proteins for TQ, respectively. Molecular dynamics (MD) simulations revealed that TQ could bind to all four target proteins, with Ddl and NADPH-dependent D-xylose reductase being the most efficient. Our findings corroborate TQ's high antimicrobial potential, suggesting it may be a promising drug candidate for multi-drug resistant (MDR) pathogens, notably Gram-positive bacteria and Candida albicans.}, } @article {pmid35052954, year = {2022}, author = {Hahne, F and Jensch, S and Hamscher, G and Meißner, J and Kietzmann, M and Kemper, N and Schulz, J and Mateus-Vargas, RH}, title = {Innovative Perspectives on Biofilm Interactions in Poultry Drinking Water Systems and Veterinary Antibiotics Used Worldwide.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052954}, issn = {2079-6382}, support = {32732/01//Deutsche Bundesstiftung Umwelt/ ; }, abstract = {Prudent use of antibiotics in livestock is widely considered to be important to prevent antibiotic resistance. This study aimed to evaluate the interactions between biofilms and veterinary antibiotics in therapeutic concentrations administrated via drinking water through a standardized experimental setup. In this context, two biofilms formed by pseudomonads (Pseudomonas (P.) aeruginosa or P. fluorescens) and a susceptible Escherichia (E.) coli strain were developed in a nutrient-poor medium on the inner surface of polyvinyl chloride pipe pieces. Subsequently, developing biofilms were exposed to sulfadiazine/trimethoprim (SDZ/TMP) or tylosin A (TYL A) in dosages recommended for application in drinking water for 5 or 7 days, respectively. Various interactions were detected between biofilms and antibiotics. Microbiological examinations revealed that only TYL A reduced the number of bacteria on the surface of the pipes. Additionally, susceptible E. coli survived both antibiotic treatments without observable changes in the minimum inhibitory concentration to 13 relevant antibiotics. Furthermore, as demonstrated by HPLC-UV, the dynamics of SDZ/TMP and TYL A in liquid media differed between the biofilms of both pseudomonads over the exposure period. We conclude that this approach represents an innovative step toward the effective evaluation of safe veterinary antibiotic use.}, } @article {pmid35052903, year = {2021}, author = {de Alteriis, E and Maione, A and Falanga, A and Bellavita, R and Galdiero, S and Albarano, L and Salvatore, MM and Galdiero, E and Guida, M}, title = {Activity of Free and Liposome-Encapsulated Essential Oil from Lavandula angustifolia against Persister-Derived Biofilm of Candida auris.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052903}, issn = {2079-6382}, abstract = {The high virulence of Candida auris, a pathogen fungus considered as a global threat for public health, is due to its peculiar traits such as its intrinsic resistance to conventional antifungals. Its biofilm lifestyle certainly promotes the prolonged survival of C. auris after disinfection or antifungal treatments. In this work, for the first time, we detected persister cells in a biofilm of C. auris in a microwell plate model, following caspofungin treatment. Furthermore, we showed how persisters can progressively develop a new biofilm in situ, mimicking the re-colonization of a surface which may be responsible for recalcitrant infections. Plant-derived compounds, such as essential oils, may represent a valid alternative to combat fungal infections. Here, Lavandula angustifolia essential oil, as free or encapsulated in liposomes, was used to eradicate primary and persister-derived biofilms of C. auris, confirming the great potential of alternative compounds against emergent fungal pathogens. As in other Candida species, the action of essential oils against C. auris involves ROS production and affects the expression of some biofilm-related genes.}, } @article {pmid35052891, year = {2021}, author = {Nicolas, M and Beito, B and Oliveira, M and Tudela Martins, M and Gallas, B and Salmain, M and Boujday, S and Humblot, V}, title = {Strategies for Antimicrobial Peptides Immobilization on Surfaces to Prevent Biofilm Growth on Biomedical Devices.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052891}, issn = {2079-6382}, abstract = {Nosocomial and medical device-induced biofilm infections affect millions of lives and urgently require innovative preventive approaches. These pathologies have led to the development of numerous antimicrobial strategies, an emergent topic involving both natural and synthetic routes, among which some are currently under testing for clinical approval and use. Antimicrobial peptides (AMPs) are ideal candidates for this fight. Therefore, the strategies involving surface functionalization with AMPs to prevent bacterial attachment/biofilms formation have experienced a tremendous development over the last decade. In this review, we describe the different mechanisms of action by which AMPs prevent bacterial adhesion and/or biofilm formation to better address their potential as anti-infective agents. We additionally analyze AMP immobilization techniques on a variety of materials, with a focus on biomedical applications. Furthermore, we summarize the advances made to date regarding the immobilization strategies of AMPs on various surfaces and their ability to prevent the adhesion of various microorganisms. Progress toward the clinical approval of AMPs in antibiotherapy is also reviewed.}, } @article {pmid35052887, year = {2021}, author = {Abdulkareem, A and Abdulbaqi, H and Gul, S and Milward, M and Chasib, N and Alhashimi, R}, title = {Classic vs. Novel Antibacterial Approaches for Eradicating Dental Biofilm as Adjunct to Periodontal Debridement: An Evidence-Based Overview.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052887}, issn = {2079-6382}, abstract = {Periodontitis is a multifactorial chronic inflammatory disease that affects tooth-supporting soft/hard tissues of the dentition. The dental plaque biofilm is considered as a primary etiological factor in susceptible patients; however, other factors contribute to progression, such as diabetes and smoking. Current management utilizes mechanical biofilm removal as the gold standard of treatment. Antibacterial agents might be indicated in certain conditions as an adjunct to this mechanical approach. However, in view of the growing concern about bacterial resistance, alternative approaches have been investigated. Currently, a range of antimicrobial agents and protocols have been used in clinical management, but these remain largely non-validated. This review aimed to evaluate the efficacy of adjunctive antibiotic use in periodontal management and to compare them to recently suggested alternatives. Evidence from in vitro, observational and clinical trial studies suggests efficacy in the use of adjunctive antimicrobials in patients with grade C periodontitis of young age or where the associated risk factors are inconsistent with the amount of bone loss present. Meanwhile, alternative approaches such as photodynamic therapy, bacteriophage therapy and probiotics showed limited supportive evidence, and more studies are warranted to validate their efficiency.}, } @article {pmid35052881, year = {2021}, author = {Albuquerque, VQ and Soares, MJC and Matos, MNC and Cavalcante, RMB and Guerrero, JAP and Soares Rodrigues, TH and Gomes, GA and de Medeiros Guedes, RF and Castelo-Branco, DSCM and Goes da Silva, IN and Carneiro, VA}, title = {Anti-Staphylococcal Activity of Cinnamomum zeylanicum Essential Oil against Planktonic and Biofilm Cells Isolated from Canine Otological Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35052881}, issn = {2079-6382}, abstract = {The aim of this study was to evaluate the phytochemical profile of Cinnamomum zeylanicum essential oil (CZEO) and their antimicrobial and antibiofilm activity against Staphylococcus strains isolated from canine otitis. First, the CZEO chemical composition was determined by gas chromatography-mass spectrometry (CG-MS). External otitis samples collected from dogs were submitted to staphylococcal isolation, followed by MALDI-TOF mass spectrometry identification. The antimicrobial action was tested against the isolates using the disk-diffusion and microdilution methods. The antibiofilm activity was evaluated by CZEO-based concentrations, subMIC for biofilm formation and supraMIC against preformed biofilm, quantified by crystal violet (CV) staining and CFU counting. The chemical analysis revealed that (E)-cinnamaldehyde, eugenol and (E)-cinnamyl acetate were the main compounds in the CZEO, representing 77.42, 8.17 and 4.50%, respectively. Two strains of three different species, S. saprophyticus, S. schleiferi and S. pseudintermedius, were identified. The disk-diffusion test showed an inhibitory zone diameter, ranging from 34.0 to 49.5 mm, while the MIC and MBC values were around 500 and 1000 µg/mL. SubMIC demonstrated an inhibition on biofilm formation against 4 out the 6 strains tested. On mature biofilm, the CZEO-based supraMIC groups had slightly change on biomass, however, the biofilm cell viability decreased the CFU in 3 magnitude orders.}, } @article {pmid35051561, year = {2022}, author = {Pani, A and Lucini, V and Dugnani, S and Scaglione, F}, title = {Erdosteine enhances antibiotic activity against bacteria within biofilm.}, journal = {International journal of antimicrobial agents}, volume = {59}, number = {3}, pages = {106529}, doi = {10.1016/j.ijantimicag.2022.106529}, pmid = {35051561}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Thioglycolates ; Thiophenes ; }, abstract = {Bacterial biofilms form on inert and living surfaces and display high levels of resistance to antibiotics, making it difficult to eradicate biofilm-related infections. Erdosteine, a thiol-based drug used in the treatment of acute and chronic respiratory diseases, has multiple pharmacodynamic properties (mucolytic, anti-inflammatory, antioxidant), suggesting that it may have potential in controlling biofilm-related infections. This in vitro study aimed to evaluate the effects of erdosteine in combination with different antibiotics against methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) biofilms. Biofilm production/mass and bacterial viability were measured using crystal violet absorbance and resorufin resonance, respectively, in young (6 h) and mature (24 h) biofilms incubated with antibiotics [at concentrations from 0 to 200 times the minimum inhibitory concentration (MIC)] for 24 h in the absence or presence of erdosteine (2, 5 and 10 mg/L). In 6-h MRSA biofilms, vancomycin and linezolid displayed concentration-dependent reductions in biofilm mass and viability, which was enhanced in the presence of increasing concentrations of erdosteine. Similar results were seen for amoxicillin/clavulanate and levofloxacin against 6-h MSSA biofilms. Antibiotics alone had reduced efficacy against 24-h biofilms, while the effect of the erdosteine-antibiotic combination was significantly greater against 24-h biofilms (MRSA and MSSA). These results suggest that erdosteine enhances the activity of the antibiotic by facilitating its penetration into biofilms and by disrupting the extracellular polymeric substance matrix, which should be confirmed with further studies. The potential clinical value of erdosteine in treating biofilm-related infections warrants further investigation.}, } @article {pmid35051518, year = {2022}, author = {Mishra, S and Huang, Y and Li, J and Wu, X and Zhou, Z and Lei, Q and Bhatt, P and Chen, S}, title = {Biofilm-mediated bioremediation is a powerful tool for the removal of environmental pollutants.}, journal = {Chemosphere}, volume = {294}, number = {}, pages = {133609}, doi = {10.1016/j.chemosphere.2022.133609}, pmid = {35051518}, issn = {1879-1298}, mesh = {Biodegradation, Environmental ; Biofilms ; *Environmental Pollutants/metabolism ; *Metals, Heavy/metabolism ; Quorum Sensing ; }, abstract = {Biofilm-mediated bioremediation is an attractive approach for the elimination of environmental pollutants, because of its wide adaptability, biomass, and excellent capacity to absorb, immobilize, or degrade contaminants. Biofilms are assemblages of individual or mixed microbial cells adhering to a living or non-living surface in an aqueous environment. Biofilm-forming microorganisms have excellent survival under exposure to harsh environmental stressors, can compete for nutrients, exhibit greater tolerance to pollutants compared to free-floating planktonic cells, and provide a protective environment for cells. Biofilm communities are thus capable of sorption and metabolization of organic pollutants and heavy metals through a well-controlled expression pattern of genes governed by quorum sensing. The involvement of quorum sensing and chemotaxis in biofilms can enhance the bioremediation kinetics with the help of signaling molecules, the transfer of genetic material, and metabolites. This review provides in-depth knowledge of the process of biofilm formation in microorganisms, their regulatory mechanisms of interaction, and their importance and application as powerful bioremediation agents in the biodegradation of environmental pollutants, including hydrocarbons, pesticides, and heavy metals.}, } @article {pmid35050870, year = {2022}, author = {Su, X and Cheng, X and Wang, Y and Luo, J}, title = {Effect of different D-amino acids on biofilm formation of mixed microorganisms.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {85}, number = {1}, pages = {116-124}, doi = {10.2166/wst.2021.623}, pmid = {35050870}, issn = {0273-1223}, mesh = {*Amino Acids ; Biofilms ; *Extracellular Polymeric Substance Matrix ; Tyrosine ; }, abstract = {This study aimed to determine the effects of D-tyrosine, D-aspartic acid, D-tryptophan and D-leucine on biofilm formation of mixed microorganisms. Results showed that, in the attachment stage, D-amino acids caused significant reduction in adhesion efficiency of mixed microorganisms to the membrane surface. Moreover, D-amino acids have a promoting effect on the reversible adhesion of mixed microorganisms. The addition of D-amino acid generally inhibited the biofilm biomass, of which D-tyrosine has the best inhibition effect. With the effect of D-tyrosine, D-aspartic acid, D-tryptophan and D-leucine, the protein in extracellular polymeric substance (EPS) decreased by 8.21%, 7.65%, 3.51% and 11.31%, respectively. The carbohydrates in EPS decreased by 29.53%, 21.44%, 14.60% and 10.54%, respectively. The results of excitation-emission matrix spectra (EEMs) suggested that the structural properties of the tyrosine-like proteins, tryptophan-like protein and humic-like acid might have changed by the D-amino acids.}, } @article {pmid35050006, year = {2022}, author = {Parker, CW and Teixeira, MM and Singh, NK and Raja, HA and Cank, KB and Spigolon, G and Oberlies, NH and Barker, BM and Stajich, JE and Mason, CE and Venkateswaran, K}, title = {Genomic Characterization of Parengyodontium torokii sp. nov., a Biofilm-Forming Fungus Isolated from Mars 2020 Assembly Facility.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {8}, number = {1}, pages = {}, pmid = {35050006}, issn = {2309-608X}, abstract = {A fungal strain (FJII-L10-SW-P1) was isolated from the Mars 2020 spacecraft assembly facility and exhibited biofilm formation on spacecraft-qualified Teflon surfaces. The reconstruction of a six-loci gene tree (ITS, LSU, SSU, RPB1 and RPB2, and TEF1) using multi-locus sequence typing (MLST) analyses of the strain FJII-L10-SW-P1 supported a close relationship to other known Parengyodontium album subclade 3 isolates while being phylogenetically distinct from subclade 1 strains. The zig-zag rachides morphology of the conidiogenous cells and spindle-shaped conidia were the distinct morphological characteristics of the P. album subclade 3 strains. The MLST data and morphological analysis supported the conclusion that the P. album subclade 3 strains could be classified as a new species of the genus Parengyodontium and placed in the family Cordycipitaceae. The name Parengyodontium torokii sp. nov. is proposed to accommodate the strain, with FJII-L10-SW-P1 as the holotype. The genome of the FJII-L10-SW-P1 strain was sequenced, annotated, and the secondary metabolite clusters were identified. Genes predicted to be responsible for biofilm formation and adhesion to surfaces were identified. Homology-based assignment of gene ontologies to the predicted proteome of P. torokii revealed the presence of gene clusters responsible for synthesizing several metabolic compounds, including a cytochalasin that was also verified using traditional metabolomic analysis.}, } @article {pmid35049646, year = {2021}, author = {Netsch, A and Horn, H and Wagner, M}, title = {On-Line Monitoring of Biofilm Accumulation on Graphite-Polypropylene Electrode Material Using a Heat Transfer Sensor.}, journal = {Biosensors}, volume = {12}, number = {1}, pages = {}, pmid = {35049646}, issn = {2079-6374}, support = {02WER1531//Federal Ministry of Education and Research/ ; }, mesh = {*Bioelectric Energy Sources ; Biofilms/growth & development ; Electrodes ; *Graphite ; Hot Temperature ; Polypropylenes/chemistry ; Stainless Steel ; }, abstract = {Biofilms growing on electrodes are the heart piece of bioelectrochemical systems (BES). Moreover, the biofilm morphology is key for the efficient performance of BES and must be monitored and controlled for a stable operation. For the industrial use of BES (i.e., microbial fuel cells for energy production), monitoring of the biofilm accumulation directly on the electrodes during operation is desirable. In this study a commercially available on-line heat transfer biofilm sensor is applied to a graphite-polypropylene (C-PP) pipe and compared to its standard version where the sensor is applied to a stainless-steel pipe. The aim was to investigate the transferability of the sensor to a carbonaceous material (C-PP), that are preferably used as electrode materials for bioelectrochemical systems, thereby enabling biofilm monitoring directly on the electrode surface. The sensor signal was correlated to the gravimetrically determined biofilm thickness in order to identify the sensitivity of the sensor for the detection and quantification of biofilm on both materials. Results confirmed the transferability of the sensor to the C-PP material, despite the sensor sensitivity being decreased by a factor of approx. 5 compared to the default biofilm sensor applied to a stainless-steel pipe.}, } @article {pmid35048191, year = {2022}, author = {Lang, KN and Sculean, A and Eick, S and Stähli, A}, title = {A novel in vitro periodontal pocket model to evaluate the effect of root surface instrumentation on biofilm-epithelial cell interactions.}, journal = {Clinical oral investigations}, volume = {26}, number = {5}, pages = {4021-4029}, pmid = {35048191}, issn = {1436-3771}, mesh = {*Biofilms ; Cell Communication ; Dental Scaling ; Humans ; *Interleukin-8 ; Periodontal Pocket/microbiology ; Surface Properties ; }, abstract = {OBJECTIVE: To develop a novel in vitro periodontal pocket model for evaluating the effect of two different root surface instrumentation modalities on biofilm-epithelial cell interactions.

MATERIALS AND METHODS: An artificial periodontal pocket model was created using an impression material. Dentin discs were prepared and incubated for 3.5 days with a biofilm consisting of 12 bacterial strains. Then, the discs were inserted into the pocket model and instrumented for 10 s or 10 strokes either with ultrasonics (US) or hand instruments (HI). Subsequently, a glass slide coated with epithelial cells was placed in close vicinity to the discs. After incubation of the pocket model in a 5% CO2 atmosphere for 6 h, residual bacteria of the biofilm as well as bacteria adhering to or invaded into epithelial cells were determined using colony-forming unit (cfu) counts and real-time PCR. Further, as a parameter of the pro-inflammatory cell response, interleukin (IL)-8 expression was determined by ELISA.

RESULTS: Compared to untreated control, HI reduced the cfu counts by 0.63 log10 (not significant) and US by 1.78 log10 (p = 0.005) with a significant difference between the treatment modalities favoring US (p = 0.048). By trend, lower detection levels of Tannerella forsythia were detected in the US group compared to HI. Concerning the interaction with epithelial cells, half of the control and the HI samples showed epithelial cells with attaching or invading bacteria, while US displayed bacteria only in two out of eight samples. In addition, US resulted in significantly lower IL-8 secretion by epithelial cells compared to the untreated control. Between HI and controls, no statistically significant difference in IL-8 secretion was found.

CONCLUSION: This newly developed in vitro model revealed in terms of biofilm-epithelial cell interaction after root surface instrumentation that compared to hand curettes, ultrasonic instrumentation appeared to be more effective in removing bacterial biofilm and in decreasing the inflammatory response of epithelium to biofilm.

CLINICAL RELEVANCE: Ultrasonic instrumentation might be more advantageous to reduce cellular inflammatory response than hand instruments.}, } @article {pmid35048077, year = {2021}, author = {Uranga, C and Nelson, KE and Edlund, A and Baker, JL}, title = {Tetramic Acids Mutanocyclin and Reutericyclin A, Produced by Streptococcus mutans Strain B04Sm5 Modulate the Ecology of an in vitro Oral Biofilm.}, journal = {Frontiers in oral health}, volume = {2}, number = {}, pages = {796140}, pmid = {35048077}, issn = {2673-4842}, support = {F32 DE026947/DE/NIDCR NIH HHS/United States ; K99 DE029228/DE/NIDCR NIH HHS/United States ; R00 DE024543/DE/NIDCR NIH HHS/United States ; R21 DE028609/DE/NIDCR NIH HHS/United States ; }, abstract = {The human oral microbiome consists of diverse microbes actively communicating and interacting through a variety of biochemical mechanisms. Dental caries is a major public health issue caused by fermentable carbohydrate consumption that leads to dysbiosis of the oral microbiome. Streptococcus mutans is a known major contributor to caries pathogenesis, due to its exceptional ability to form biofilms in the presence of sucrose, as well as to its acidophilic lifestyle. S. mutans can also kill competing bacteria, which are typically health associated, through the production of bacteriocins and other small molecules. A subset of S. mutans strains encode the muc biosynthetic gene cluster (BGC), which was recently shown to produce the tetramic acids, mutanocyclin and reutericyclins A, B, and C. Reutericyclin A displayed strong antimicrobial activity and mutanocyclin appeared to be anti-inflammatory; however the effect of these compounds, and the carriage of muc by S. mutans, on the ecology of the oral microbiota is not known, and was examined here using a previously developed in vitro biofilm model derived from human saliva. While reutericyclin significantly inhibited in vitro biofilm formation and acid production at sub-nanomolar concentrations, mutanocyclin did not present any activity until the high micromolar range. 16S rRNA gene sequencing revealed that reutericyclin drastically altered the biofilm community composition, while mutanocyclin showed a more specific effect, reducing the relative abundance of cariogenic Limosilactobacillus fermentum. Mutanocyclin or reutericyclin produced by the S. mutans strains amended to the community did not appear to affect the community in the same way as the purified compounds, although the results were somewhat confounded by the differing growth rates of the S. mutans strains. Regardless of the strain added, the addition of S. mutans to the in vitro community significantly increased the abundance of S. mutans and Veillonella infantium, only. Overall, this study illustrates that reutericyclin A and mutanocyclin do impact the ecology of a complex in vitro oral biofilm; however, further research is needed to determine the extent to which the production of these compounds affects the virulence of S. mutans.}, } @article {pmid35048073, year = {2021}, author = {Zhou, P and Manoil, D and Belibasakis, GN and Kotsakis, GA}, title = {Veillonellae: Beyond Bridging Species in Oral Biofilm Ecology.}, journal = {Frontiers in oral health}, volume = {2}, number = {}, pages = {774115}, pmid = {35048073}, issn = {2673-4842}, abstract = {The genus Veillonella comprises 16 characterized species, among which eight are commonly found in the human oral cavity. The high abundance of Veillonella species in the microbiome of both supra- and sub-gingival biofilms, and their interdependent relationship with a multitude of other bacterial species, suggest veillonellae to play an important role in oral biofilm ecology. Development of oral biofilms relies on an incremental coaggregation process between early, bridging and later bacterial colonizers, ultimately forming multispecies communities. As early colonizer and bridging species, veillonellae are critical in guiding the development of multispecies communities in the human oral microenvironment. Their ability to establish mutualistic relationships with other members of the oral microbiome has emerged as a crucial factor that may contribute to health equilibrium. Here, we review the general characteristics, taxonomy, physiology, genomic and genetics of veillonellae, as well as their bridging role in the development of oral biofilms. We further discuss the role of Veillonella spp. as potential "accessory pathogens" in the human oral cavity, capable of supporting colonization by other, more pathogenic species. The relationship between Veillonella spp. and dental caries, periodontitis, and peri-implantitis is also recapitulated in this review. We finally highlight areas of future research required to better understand the intergeneric signaling employed by veillonellae during their bridging activities and interspecies mutualism. With the recent discoveries of large species and strain-specific variation within the genus in biological and virulence characteristics, the study of Veillonella as an example of highly adaptive microorganisms that indirectly participates in dysbiosis holds great promise for broadening our understanding of polymicrobial disease pathogenesis.}, } @article {pmid35048065, year = {2021}, author = {Wagenknecht, DR and Gregory, RL}, title = {Analyses of the Effects of Arginine, Nicotine, Serotype and Collagen-Binding Proteins on Biofilm Development by 33 Strains of Streptococcus mutans.}, journal = {Frontiers in oral health}, volume = {2}, number = {}, pages = {764784}, pmid = {35048065}, issn = {2673-4842}, abstract = {Streptococcus mutans serotype k strains comprise <3% of oral isolates of S. mutans but are prominent in diseased cardiovascular (CV) tissue. Collagen binding protein (CBP) genes, cbm and cnm, are prevalent in serotype k strains and are associated with endothelial cell invasion. Nicotine increases biofilm formation by serotype c strains of S. mutans, but its effects on serotype k strains and strains with CBP are unknown. Saliva contains arginine which alters certain properties of the extracellular polysaccharides (EPS) in S. mutans biofilm. We examined whether nicotine and arginine affect sucrose-induced biofilm of S. mutans serotypes k (n = 23) and c (n = 10) strains with and without CBP genes. Biofilm mass, metabolism, bacterial proliferation, and EPS production were assessed. Nicotine increased biomass and metabolic activity (p < 0.0001); arginine alone had no effect. The presence of a CBP gene (either cbm or cnm) had a significant effect on biofilm production, but serotype did not. Nicotine increased bacterial proliferation and the effect was greater in CBP + strains compared to strains lacking CBP genes. Addition of arginine with nicotine decreased both bacterial mass and EPS compared to biofilm grown in nicotine alone. EPS production was greater in cnm + than cbm + strains (p < 0.0001). Given the findings of S. mutans in diseased CV tissue, a nicotine induced increase in biofilm production by CBP + strains may be a key link between tobacco use and CV diseases.}, } @article {pmid35048053, year = {2021}, author = {Taylor, ES and Gomez, GF and Moser, EAS and Sanders, BJ and Gregory, RL}, title = {Effect of a Tea Polyphenol on Different Levels of Exposure of Nicotine and Tobacco Extract on Streptococcus mutans Biofilm Formation.}, journal = {Frontiers in oral health}, volume = {2}, number = {}, pages = {737378}, pmid = {35048053}, issn = {2673-4842}, abstract = {Objective: The purpose of this study was to compare the effects of different levels of nicotine and tobacco extract exposure on Streptococcus mutans biofilm formation and the inhibitory effect of the polyphenol epigallocatechin-3 gallate (EGCG) found in green tea. This study addressed the results of biofilm assays with EGCG and varying relative concentrations of nicotine and tobacco extract consistent with primary, secondary and tertiary levels of smoking exposure. Primary smoking exposure to nicotine has been demonstrated to significantly increase biofilm formation, while EGCG has been demonstrated to reduce S. mutans biofilm formation. Methods: S. mutans was treated with varying levels of nicotine or cigarette smoke condensate (CSC) concentrations (0-32 mg/ml and 0-2 mg/ml, respectively) in Tryptic Soy broth supplemented with 1% sucrose for different lengths of time simulating primary, secondary and tertiary smoking exposure with and without 0.25 mg/ml EGCG. The amount of total growth and biofilm formed was determined using a spectrophotometric crystal violet dye staining assay. Results: For both nicotine and CSC, primary exposure displayed overall significantly less growth compared to secondary exposure. For nicotine, secondary exposure demonstrated significantly greater growth than tertiary exposure levels. Overall, significantly greater total bacterial growth and biofilm formation in the presence of nicotine and CSC was observed in the absence of EGCG than in the presence of EGCG. However, biofilm growth was not significantly different among different concentrations of CSC. Conclusion: The results of this study help illustrate that nicotine-induced S. mutans biofilm formation is reduced by the presence of EGCG. This provides further evidence of the potential beneficial properties of polyphenols.}, } @article {pmid35048047, year = {2021}, author = {Albaghdadi, SZ and Altaher, JB and Drobiova, H and Bhardwaj, RG and Karched, M}, title = {In vitro Characterization of Biofilm Formation in Prevotella Species.}, journal = {Frontiers in oral health}, volume = {2}, number = {}, pages = {724194}, pmid = {35048047}, issn = {2673-4842}, abstract = {Background: Periodontitis, a chronic inflammatory oral infection is the outcome of disturbances in the homeostasis of the oral biofilm microbiota. A number of studies have found the occurrence of Prevotella species in elevated levels in periodontitis compared to healthy subjects. Even though different aspects of Prevotella as part of oral biofilm have been studied, in vitro biofilms formed by these species have not been characterized systematically. The objective of this study was to characterize biofilms formed by several Prevotella species and further to assess biofilm inhibition and detachment of preformed biofilms. Methods: Biofilms were grown in 24-well plates containing brucella broth in anaerobic conditions for 3 days, and were quantified using crystal violet staining. Images of SYTO 9 Green fluorescent stained biofilms were captured using confocal microscopy. Biofilm inhibition and detachment by proteinase and DNase I was tested. The biochemical characterization included quantification of proteins and DNA in the biofilms and biofilm-supernatants. Results: Prevotella loescheii, Prevotella oralis and Prevotella nigrescens showed highest biofilm formation. P. nigrescens formed significantly higher amounts of biofilms than P. loescheii (P = 0.005) and P. oralis (P = 0.0013). Inhibition of biofilm formation was significant only in the case of P. oralis when treated with proteinase (P = 0.037), whereas with DNase I treatment, the inhibition was not significant (P = 0.531). Overall, proteinase was more effective in biofilm detachment than DNase I. Protein and DNA content were higher in biofilm than the supernatant with the highest amounts found in P. nigrescens biofilm and supernatants. P. oralis biofilms appeared to secrete large amounts of proteins extracellularly into the biofilm-supernatants. Conclusion: Significant differences among Prevotella species to form biofilms may imply their variable abilities to get integrated into oral biofilm communities. Of the species that were able to grow as biofilms, DNase I and proteinase inhibited the biofilm growth or were able to cause biofilm detachment.}, } @article {pmid35047965, year = {2021}, author = {Giordani, B and Parolin, C and Vitali, B}, title = {Lactobacilli as Anti-biofilm Strategy in Oral Infectious Diseases: A Mini-Review.}, journal = {Frontiers in medical technology}, volume = {3}, number = {}, pages = {769172}, pmid = {35047965}, issn = {2673-3129}, abstract = {The spread of biofilm-related diseases in developed countries has led to increased mortality rates and high health care costs. A biofilm is a community of microorganisms that is irreversibly attached to a surface, behaving very differently from planktonic cells and providing resistance to antimicrobials and immune response. Oral diseases are an excellent example of infection associated with the formation of highly pathogenic biofilms. It is generally accepted that, when the oral homeostasis is broken, the overgrowth of pathogens is facilitated. Among them, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are the main etiological agents of periodontitis, while Streptococcus mutans is strongly associated with the onset of dental caries. Other microorganisms, such as the fungus Candida albicans, may also be present and contribute to the severity of infections. Since the common antibiotic therapies usually fail to completely eradicate biofilm-related oral diseases, alternative approaches are highly required. In this regard, the topical administration of probiotics has recently gained interest in treating oral diseases. Thus, the present mini-review focuses on the possibility of using Lactobacillus spp. as probiotics to counteract biofilm-mediated oral infections. Many evidence highlight that Lactobacillus living cells can impede the biofilm formation and eradicate mature biofilms of different oral pathogens, by acting through different mechanisms. Even more interestingly, lactobacilli derivatives, namely postbiotics (soluble secreted products) and paraprobiotics (cell structural components) are able to trigger anti-biofilm effects too, suggesting that they can represent a novel and safer alternative to the use of viable cells in the management of biofilm-related oral diseases.}, } @article {pmid35046911, year = {2021}, author = {Bao, J and Xie, L and Ma, Y and An, R and Gu, B and Wang, C}, title = {Proteomic and Transcriptomic Analyses Indicate Reduced Biofilm-Forming Abilities in Cefiderocol-Resistant Klebsiella pneumoniae.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {778190}, pmid = {35046911}, issn = {1664-302X}, abstract = {The advent of cefiderocol provides hope for the clinical treatment of multi-drug resistant gram-negative bacteria (GNB), especially those with carbapenem resistance. Resistance of Klebsiella pneumoniae to cefiderocol can be enhanced by acclimatization. In the present study, we collected cefiderocol resistant K. pneumoniae isolates during a 36-day acclimatization procedure while increasing the cefiderocol concentration in the culture medium. Strains were studied for changes in their biological characteristics using proteomics and transcriptomics. A decrease in biofilm formation ability was the main change observed among the induced isolates. Downregulation of genes involved in biofilm formation including hdeB, stpA, yhjQ, fba, bcsZ, uvrY, bcsE, bcsC, and ibpB were the main factors that reduced the biofilm formation ability. Moreover, downregulation of siderophore transporter proteins including the iron uptake system component efeO, the tonB-dependent receptor fecA, and ferric iron ABC transporter fbpA may be among the determining factors leading to cefiderocol resistance and promoting the reduction of biofilm formation ability of K. pneumoniae. This is the first study to investigate cefiderocol resistance based on comprehensive proteomic and transcriptomic analyses.}, } @article {pmid35046807, year = {2021}, author = {Zhang, L and Yang, W and Chu, Y and Wen, B and Cheng, Y and Mahmood, T and Bao, M and Ge, F and Li, L and Yi, J and Du, C and Lu, C and Tan, Y}, title = {The Inhibition Effect of Linezolid With Reyanning Mixture on MRSA and its Biofilm is More Significant than That of Linezolid Alone.}, journal = {Frontiers in pharmacology}, volume = {12}, number = {}, pages = {766309}, pmid = {35046807}, issn = {1663-9812}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a superbacterium, and when it forms biofilms, it is difficult to treat even with the first-line of antibiotic linezolid (LNZ). Reyanning mixture (RYN), a compound-based Chinese medicine formula, has been found to have inhibitory effects on biofilms. This study aims to explore the synergistic inhibitory effect and corresponding mechanisms of their (LNZ&RYN) combination on the planktonic as well as biofilm cells of MRSA. Broth microdilution and chessboard methods were employed for the determination of minimum inhibitory concentrations (MICs) and synergistic concentration of LNZ&RYN, respectively. The effect of the combined medication on biofilm and mature biofilm of MRSA were observed by biofilm morphology and permeability experiments, respectively. To unveil the molecular mechanism of action of the synergistic combination of LNZ and RYN, RT-PCR based biofilm-related gene expression analysis and ultra-high pressure liquid chromatography-time-of-flight mass spectrometry based endogenous metabonomic analysis were deployed. The results indicated that 1/16RYN as the best combined dose reduced LNZ (4 μg/ml) to 2 μg/ml. The combined treatment inhibited living MRSA before and after biofilm formation, removed the residual structure of dead bacteria in MRSA biofilms and affected the shape and size of bacteria, resulting in the improvement of biofilm permeability. The mechanism was that biofilm-related genes such as agrC, atlA, and sarA, as well as amino acid uptake associated with the metabolism of 3-dehydrocarnitine, kynurenine, L-leucine, L-lysine and sebacic acid were inhibited. This study provides evidence for the treatment of MRSA and its biofilms with LNZ combined with RYN.}, } @article {pmid35045178, year = {2022}, author = {Pant, N and Wallis, SC and Roberts, JA and Eisen, DP}, title = {In vitro effect of synovial fluid from patients undergoing arthroplasty surgery on MRSA biofilm formation.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {77}, number = {4}, pages = {1041-1044}, doi = {10.1093/jac/dkab497}, pmid = {35045178}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Arthroplasty/adverse effects ; Biofilms ; Cefazolin/pharmacology ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections/microbiology ; Synovial Fluid ; }, abstract = {BACKGROUND: Bacterial biofilm is a key component in the pathogenesis of prosthetic joint infection (PJI). Synovial fluid has been shown to have inhibitory activity against planktonic bacteria. However, the contribution of synovial fluid in prevention of Staphylococcus aureus (including MRSA) planktonic and biofilm forms is unknown.

OBJECTIVES: To test the antibacterial and antibiofilm activities of synovial fluid, including that containing cefazolin, against MSSA and MRSA.

MATERIALS AND METHODS: We determined the antiplanktonic and antibiofilm activities of synovial fluid collected from patients given preoperative cefazolin while undergoing elective arthroplasty surgery. MICs of cefazolin were determined for planktonic and biofilm cultures of biofilm-forming strains of MSSA and MRSA.

RESULTS: Synovial fluid inhibited planktonic and biofilm cultures of MSSA and MRSA. Cefazolin-containing synovial fluid had greater antibacterial and antibiofilm activities than the same cefazolin concentration in glucose LB (GLB) broth. MSSA and MRSA MICs of cefazolin suspended in synovial fluid were 0.7 mg/L. The MICs of cefazolin diluted in GLB broth were higher, measuring 1.4 mg/L for MSSA and 23 mg/L for MRSA.

CONCLUSIONS: Synovial fluid containing cefazolin inhibited biofilm- and planktonic-state MRSA cultures. This may explain the apparent effect of cefazolin in the prevention of MRSA PJI.}, } @article {pmid35044804, year = {2022}, author = {Chen, MY and Alexiev, A and McKenzie, VJ}, title = {Bacterial Biofilm Thickness and Fungal Inhibitory Bacterial Richness Both Prevent Establishment of the Amphibian Fungal Pathogen Batrachochytrium dendrobatidis.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {5}, pages = {e0160421}, pmid = {35044804}, issn = {1098-5336}, mesh = {Amphibians/genetics/microbiology ; Animals ; Bacteria ; Batrachochytrium ; Biofilms ; *Chytridiomycota/genetics ; Humans ; *Microbiota/genetics ; RNA, Ribosomal, 16S/genetics ; Skin/microbiology ; }, abstract = {Host-associated microbial biofilms can provide protection against pathogen establishment. In many host-microbe symbioses (including, but not limited to humans, plants, insects, and amphibians), there is a correlation between host-associated microbial diversity and pathogen infection risk. Diversity may prevent infection by pathogens through sampling effects and niche complementarity, but an alternative hypothesis may be that microbial biomass is confounded with diversity and that host-associated biofilms are deterring pathogen establishment through space preemption. In this study, we use the amphibian system as a model for host-microbe-pathogen interactions to ask two questions: (i) is bacterial richness confounded with biofilm thickness or cell density, and (ii) to what extent do biofilm thickness, cell density, and bacterial richness each deter the establishment of the amphibian fungal pathogen Batrachochytrium dendrobatidis? To answer these questions, we built a custom biofilm microcosm that mimics the host-environment interface by allowing nutrients to diffuse out of a fine-pore biofilm scaffolding. This created a competitive environment in which bacteria and the fungal pathogen compete for colonization space. We then challenged bacterial biofilms ranging in community richness, biofilm thickness, bacterial cell density, and B. dendrobatidis (also known as Bd)-inhibitory metabolite production with live B. dendrobatidis zoospores to determine how B. dendrobatidis establishment success on membranes varies. We found that biofilm thickness and B. dendrobatidis-inhibitory isolate richness work in complement to reduce B. dendrobatidis establishment success. This work underscores that physical aspects of biofilm communities can play a large role in pathogen inhibition, and in many studies, these traits are not studied. IMPORTANCE Our finding highlights the fact that diversity, as measured through 16S rRNA gene sequencing, may obscure the true mechanisms behind microbe-mediated pathogen defense and that physical space occupation by biofilm-forming symbionts may significantly contribute to pathogen protection. These findings have implications across a wide range of host-microbe systems since 16S rRNA gene sequencing is a standard tool used across many microbial systems. Further, our results are potentially relevant to many host-pathogen systems since host-associated bacterial biofilms are ubiquitous.}, } @article {pmid35041982, year = {2022}, author = {Ribeiro, IP and Pinto, JG and Souza, BMN and Miñán, AG and Ferreira-Strixino, J}, title = {Antimicrobial photodynamic therapy with curcumin on methicillin-resistant Staphylococcus aureus biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {37}, number = {}, pages = {102729}, doi = {10.1016/j.pdpdt.2022.102729}, pmid = {35041982}, issn = {1873-1597}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; *Curcumin/pharmacology ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Staphylococcus aureus ; }, abstract = {Healthcare-Associated Infections (HAI) effect approximately 1.5 million individuals worldwide. Among the causes of HAIs in Latin America, Staphylococcus aureus presents a severe danger due to its rapid spread and ease of developing antibiotic resistance. Upon acquiring methicillin resistance, it receives the classification Methicillin-Resistant Staphylococcus aureus (MRSA), responsible for 40 to 60% of HAIs. The increase in resistant microorganisms led to the search for alternative methods, such as antimicrobial Photodynamic Therapy (aPDT), forming Reactive Oxygen Species (ROS), leading bacterial cells to death. The objective of this work was to evaluate in vitro the antimicrobial action of PDT with curcumin in MRSA biofilm. The strains were induced to form biofilm and incubated with curcumin for 20 min, irradiated with LED (Light Emitting Diode) 450 nm, at 110 mW/cm2, 50 J/cm2 for 455 s, subsequently counting the Colony Forming Units, Scanning Electron Microscopy (SEM) micrographs, Confocal Microscopy images, Resazurin dye test, ROS quantification to assess the effect of PDT on biofilm. The results show that PDT with curcumin reduced the biofilm growth of the MRSA strain. In addition, confocal microscopy showed that curcumin was internalized by S. aureus in the cells at the concentration used, and when isolated, curcumin and the irradiation parameter did not show cytotoxicity. The study demonstrated that the PDT in the established parameters reduced the growth of the MRSA strain biofilm, making it a relevant alternative possibility for the inactivation of this strain.}, } @article {pmid35041509, year = {2022}, author = {Bilal, H and Tait, JR and Lang, Y and Zhou, J and Bergen, PJ and Peleg, AY and Bulitta, JB and Oliver, A and Nation, RL and Landersdorfer, CB}, title = {Simulated Intravenous versus Inhaled Tobramycin with or without Intravenous Ceftazidime Evaluated against Hypermutable Pseudomonas aeruginosa via a Dynamic Biofilm Model and Mechanism-Based Modeling.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {3}, pages = {e0220321}, pmid = {35041509}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Ceftazidime/pharmacology/therapeutic use ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections/drug therapy/microbiology ; *Pseudomonas aeruginosa ; Tobramycin/pharmacology/therapeutic use ; }, abstract = {Acute exacerbations of chronic respiratory infections in patients with cystic fibrosis are highly challenging due to hypermutable Pseudomonas aeruginosa, biofilm formation and resistance emergence. We aimed to systematically evaluate the effects of intravenous versus inhaled tobramycin (TOB) with and without intravenous ceftazidime (CAZ). Two hypermutable P. aeruginosa isolates, CW30 (MICCAZ, 0.5 mg/liter; MICTOB, 2 mg/liter) and CW8 (MICCAZ, 2 mg/liter; MICTOB, 8 mg/liter), were investigated for 120 h in dynamic in vitro biofilm studies. Treatments were intravenous ceftazidime, 9 g/day (33% lung fluid penetration); intravenous tobramycin, 10 mg/kg of body every 24 h (50% lung fluid penetration); inhaled tobramycin, 300 mg every 12 h; and both ceftazidime-tobramycin combinations. Total and less susceptible planktonic and biofilm bacteria were quantified over 120 h. Mechanism-based modeling was performed. All monotherapies were ineffective for both isolates, with regrowth of planktonic (≥4.7 log10 CFU/ml) and biofilm (>3.8 log10 CFU/cm[2]) bacteria and resistance amplification by 120 h. Both combination treatments demonstrated synergistic or enhanced bacterial killing of planktonic and biofilm bacteria. With the combination simulating tobramycin inhalation, planktonic bacterial counts of the two isolates at 120 h were 0.47% and 36% of those for the combination with intravenous tobramycin; for biofilm bacteria the corresponding values were 8.2% and 13%. Combination regimens achieved substantial suppression of resistance of planktonic and biofilm bacteria compared to each antibiotic in monotherapy for both isolates. Mechanism-based modeling well described all planktonic and biofilm counts and indicated synergy of the combination regimens despite reduced activity of tobramycin in biofilm. Combination regimens of inhaled tobramycin with ceftazidime hold promise to treat acute exacerbations caused by hypermutable P. aeruginosa strains and warrant further investigation.}, } @article {pmid35041503, year = {2022}, author = {Blasco, L and Bleriot, I and González de Aledo, M and Fernández-García, L and Pacios, O and Oliveira, H and López, M and Ortiz-Cartagena, C and Fernández-Cuenca, F and Pascual, Á and Martínez-Martínez, L and Pachón, J and Azeredo, J and Tomás, M}, title = {Development of an Anti-Acinetobacter baumannii Biofilm Phage Cocktail: Genomic Adaptation to the Host.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {3}, pages = {e0192321}, pmid = {35041503}, issn = {1098-6596}, mesh = {*Acinetobacter Infections/microbiology ; *Acinetobacter baumannii/genetics ; *Bacteriophages/genetics ; Biofilms ; Genome, Viral ; Genomics ; Humans ; }, abstract = {The need for alternatives to antibiotic therapy due to the emergence of multidrug resistant bacteria (MDR), such as the nosocomial pathogen Acinetobacter baumannii, has led to the recovery of phage therapy. In addition, phages can be combined in cocktails to increase the host range. In this study, the evolutionary mechanism of adaptation was utilized in order to develop a phage adapted to A. baumannii, named phage Ab105-2phiΔCI404ad, from a mutant lytic phage, Ab105-2phiΔCI, previously developed by our group. The whole genome sequence of phage Ab105-2phiΔCI404ad was determined, showing that four genomic rearrangements events occurred in the tail morphogenesis module affecting the ORFs encoding the host receptor binding sites. As a consequence of the genomic rearrangements, 10 ORFs were lost and four new ORFs were obtained, all encoding tail proteins; two inverted regions were also derived from these events. The adaptation process increased the host range of the adapted phage by almost 3-fold. In addition, a depolymerase-expressing phenotype, indicated by formation of a halo, which was not observed in the ancestral phage, was obtained in 81% of the infected strains. A phage cocktail was formed by combining this phage with the A. baumannii phage vB_AbaP_B3, known to express a depolymerase. Both the individual phages and the phage cocktail showed strong antimicrobial activity against 5 clinical strains and 1 reference strain of A. baumannii tested. However, in all cases resistance to the bacterial strains was also observed. The antibiofilm activity of the individual phages and the cocktail was assayed. The phage cocktail displayed strong antibiofilm activity.}, } @article {pmid35038547, year = {2022}, author = {Tan, Q and Ai, Q and He, Y and Li, F and Yu, J}, title = {P. aeruginosa biofilm activates the NLRP3 inflammasomes in vitro.}, journal = {Microbial pathogenesis}, volume = {164}, number = {}, pages = {105379}, doi = {10.1016/j.micpath.2021.105379}, pmid = {35038547}, issn = {1096-1208}, mesh = {Biofilms ; Caspase 1/metabolism ; Humans ; *Inflammasomes/metabolism ; Interleukin-18/genetics/*metabolism ; Interleukin-1beta/*metabolism ; NLR Family, Pyrin Domain-Containing 3 Protein/*genetics/metabolism ; Pseudomonas aeruginosa/metabolism ; THP-1 Cells ; }, abstract = {The ability of P.aeruginosa to form biofilms renders common treatments inefficient, thereby promoting chronic infection. Inflammasomes activate caspase-1, which is important for the maturation of IL-1β and IL-18 and evoke an inflammatory response. We aimed to investigate the activation of inflammasomes induced by P.aeruginosa biofilm. THP-1 cells were mock-infected or infected with PAO1 biofilms. Protein levels of caspase-1 p20, pro-caspase-1, caspase-4 p20, and pro-caspase-4 in THP-1 macrophages were determined by Western blotting. The expression of NLRC4 and NLRP3 was measured by RT-PCR. The production of IL-1β and IL-18 was monitored using ELISA. P. aeruginosa biofilm significantly elevated caspase-1 levels, and decreased NLRC4 levels. Additionally, caspase-4 and NLRP3 levels were significantly increased. P.aeruginosa biofilm significantly enhanced IL-1β and IL-18 production. We concluded that P. aeruginosa biofilm induced the production of IL-1β and IL-18, possibly via NLRP3 inflammasomes, rather than NLRC4 inflammasomes.}, } @article {pmid35038509, year = {2022}, author = {Wen, L and Huang, L and Wang, Y and Yuan, Y and Zhou, L}, title = {Facet-engineered hematite boosts microbial electrogenesis by synergy of promoting electroactive biofilm formation and extracellular electron transfer.}, journal = {The Science of the total environment}, volume = {819}, number = {}, pages = {153154}, doi = {10.1016/j.scitotenv.2022.153154}, pmid = {35038509}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Electron Transport ; *Electrons ; Ferric Compounds ; }, abstract = {Hematite has been proven to be an excellent material for enhancing extracellular electron transfer (EET) in microbial bioelectrochemical systems (BESs). However, the effect of hematite with different exposed facets on microbial EET remains unclear. Here, we synthesized two types of hematite nanoparticles with high {100} and {001} facet exposure (Hem_{100} and Hem_{001} ), respectively, which were coated on ITO electrode to stimulate the microbial EET in the BESs. The results showed that the maximum biocurrent density of commercial hematite nanoparticles (Hem_NPs), Hem_{100} and Hem_{001} electrodes reached 73.33 ± 5.68, 129.33 ± 9.12 and 287.00 ± 19.89 μA cm[-2] from three replicates of each treatment, respectively. The current generation achieved from the Hem_{001} electrode was nearly 199-times higher than that of the blank ITO electrode (1.44 ± 0.10 μA cm[-2]). The electrochemical measurements showed that the lowest charge transfer resistance (Rct) was observed for the Hem_{001}, and the promoted biofilm formation and EPS secretion on the Hem_{001} electrode were also revealed, which could contribute the high performance of this electrode. Moreover, metagenomic analysis revealed that Hem_{001} might facilitate the microbial EET by stimulating the expression of genes related to cytochrome c and conductive nanowires. This study not only provides a new strategy to enhance microbial electrogenesis but also expands the knowledge of the effect of facet on microbial EET, helping to develop more efficient electrode materials in the future.}, } @article {pmid35037424, year = {2022}, author = {Xie, J and Meng, Z and Han, X and Li, S and Ma, X and Chen, X and Liang, Y and Deng, X and Xia, K and Zhang, Y and Zhu, H and Fu, T}, title = {Cholesterol Microdomain Enhances the Biofilm Eradication of Antibiotic Liposomes.}, journal = {Advanced healthcare materials}, volume = {11}, number = {8}, pages = {e2101745}, doi = {10.1002/adhm.202101745}, pmid = {35037424}, issn = {2192-2659}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Cholesterol ; Drug Carriers/pharmacology ; *Liposomes/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {Resistance and tolerance of biofilms to antibiotics is the greatest challenge in the treatment of bacterial infections. Therefore, developing an effective strategy against biofilms is a top priority. Liposomes are widely used as antibiotic drug carriers; however, common liposomes lack affinity for biofilms. Herein, biofilm-targeted antibiotic liposomes are created by simply adjusting their cholesterol content. The tailored liposomes exhibit significantly enhanced bacterial inhibition and biofilm eradication effects that are positively correlated with the cholesterol content of liposomes. The experiments further demonstrate that this enhanced effect can be ascribed to the effective drug release through the pores, which are formed by the combination of cholesterol microdomains in liposomal lipid bilayers with membrane-damaged toxins in biofilms. Consequently, liposome encapsulation with a high cholesterol concentration improves noticeably the pharmacodynamics and biocompatibility of antibiotics after pulmonary administration. This work may provide a new direction for the development of antibiofilm formulations that can be widely used for the treatment of infections caused by bacterial biofilms.}, } @article {pmid35037233, year = {2022}, author = {Alarcón-Vivero, M and Moena, NR and Gonzalez, F and Jopia-Contreras, P and Aspé, E and Briones, HU and Fernandez, KS}, title = {Anaerobic biofilm enriched with an ammonia tolerant methanogenic consortium to improve wastewater treatment in the fishing industry.}, journal = {Biotechnology letters}, volume = {44}, number = {2}, pages = {239-251}, pmid = {35037233}, issn = {1573-6776}, support = {203.031.095-1.0//dic udec/ ; }, mesh = {*Ammonia/analysis/metabolism ; Anaerobiosis ; Animals ; Biofilms ; *Bioreactors/microbiology ; Fishes ; *Food-Processing Industry ; Methane/metabolism ; *Water Purification ; }, abstract = {The digestion efficiency of liquid industrial wastes increases when using bioreactors colonized by microbial biofilms. High concentrations of proteins derived from the fish processing industry lead to the production of ammonia, which inhibits methane production. Two bioreactors were constructed to compare methanogenic activity: one enriched with mMPA (methylaminotrofic methane production archaea) consortia (control bioreactor), and the second with NH3 tolerant consortia (treatment bioreactor). Ammonia tolerant activity was assessed by applying an ammonia shock (755 mg NH3/L). Methane production, consumption of total organic carbon (TOC) and the taxonomic composition of bacteria and archaea was evaluated using 16S rDNA in the acclimatization, ammonia shock, and recovery phases.The ammonia shock significantly affected both methane production and the consumption of TOC in the control reactor (p < 0.05) and taxonomical composition of the microbial consortia (OTU). These values remained constant in the treatment reactor. The analysis of biofilm composition showed a predominance of Methanosarcinaceae (Methanomethylovorans sp., and probably two different species of Methanosarcina sp.) in bioreactors. These results demonstrate that using acclimated biofilms enriched with ammonia tolerant methanogens control the inhibitory effect of ammonia on methanogenesis.}, } @article {pmid35036275, year = {2022}, author = {Wang, X and He, Y and Deng, Y and Zuo, Z and Li, D and Chen, F and Qu, C and Miao, J}, title = {A diguanylate cyclase regulates biofilm formation in Rhodococcus sp. NJ-530 from Antarctica.}, journal = {3 Biotech}, volume = {12}, number = {1}, pages = {27}, pmid = {35036275}, issn = {2190-572X}, abstract = {UNLABELLED: Biofilms represent a protective survival mode in which bacteria adapt themselves to the natural environment for survival purposes. Biofilm formation is regulated by 3,5-cyclic diguanylic acid (c-di-GMP), which is a universal second messenger molecule in bacteria. Diguanylate cyclase (DGC) catalyses c-di-GMP intracellular synthesis, which plays important roles in bacterial adaptation to the natural environment. In this study, the DGC gene was first cloned from Antarctic Rhodococcus sp. NJ-530. DGC contained 948 nucleotides and encoded 315 amino acids with a molecular weight of 34.6 KDa and an isoelectric point of 5.58. qRT-PCR demonstrated that the DGC expression level was significantly affected by lower salinity and temperature. Consistently, more biofilm formation occurred under the same stress. It has been shown that Rhodococcus sp. NJ-530 can adapt to the extreme environment in Antarctica, which is closely related to biofilm formation. These results provide an important reference for studying the adaptive mechanism of Antarctic microorganisms to this extreme environment.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-03093-z.}, } @article {pmid35034106, year = {2022}, author = {Li, S and Liu, SY and Chan, SY and Chua, SL}, title = {Biofilm matrix cloaks bacterial quorum sensing chemoattractants from predator detection.}, journal = {The ISME journal}, volume = {16}, number = {5}, pages = {1388-1396}, pmid = {35034106}, issn = {1751-7370}, support = {BE2B//Hong Kong Polytechnic University (Hong Kong PolyU)/ ; }, mesh = {Animals ; Bacteria/genetics ; Biofilms ; Caenorhabditis elegans ; Chemotactic Factors ; *Extracellular Polymeric Substance Matrix ; *Quorum Sensing ; }, abstract = {Microbes often secrete high levels of quorum sensing (QS) autoinducers into the environment to coordinate gene expression and biofilm formation, but risk detection and subsequent predation by bacterivorous predators. With such prominent signaling molecules acting as chemoattractants that diffuse into the environment at alarmingly high concentrations, it is unclear if bacterial cells can mask their chemical trails from predator detection. Here, we describe a microbial-based anti-detection adaptation, termed as "biofilm cloak", where the biofilm prey produced biofilm matrix exopolysaccharides that "locked" and reduced the leaching of autoinducers into the milieu, thereby concealing their trails to the detection by the bacterivorous Caenorhabditis elegans nematode. The exopolysaccharides act as common good for the non-producers to hide their autoinducers from predator detection. Deficiency in chemosensory gene odr-10 in mutant animals abrogated their ability to detect autoinducers and migrate toward their prey in a directed manner, which led to lower population growth rate of animals. Hence, restriction of bacterial communication activities to the confinements of biofilms is a novel approach for predator evasion, which plays a fundamental role in shaping ecological dynamics of microbial communities and predator-prey interactions.}, } @article {pmid35033903, year = {2022}, author = {He, Y and Luckett, J and Begines, B and Dubern, JF and Hook, AL and Prina, E and Rose, FRAJ and Tuck, CJ and Hague, RJM and Irvine, DJ and Williams, P and Alexander, MR and Wildman, RD}, title = {Ink-jet 3D printing as a strategy for developing bespoke non-eluting biofilm resistant medical devices.}, journal = {Biomaterials}, volume = {281}, number = {}, pages = {121350}, pmid = {35033903}, issn = {1878-5905}, support = {103882/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; 103884/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; MC_G0802525/MRC_/Medical Research Council/United Kingdom ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Animals ; Bacteria ; Biocompatible Materials/chemistry ; *Biofilms ; *Ink ; Mammals ; Mice ; Printing, Three-Dimensional ; Pseudomonas aeruginosa ; Reproducibility of Results ; Staphylococcus aureus ; }, abstract = {Chronic infection as a result of bacterial biofilm formation on implanted medical devices is a major global healthcare problem requiring new biocompatible, biofilm-resistant materials. Here we demonstrate how bespoke devices can be manufactured through ink-jet-based 3D printing using bacterial biofilm inhibiting formulations without the need for eluting antibiotics or coatings. Candidate monomers were formulated and their processability and reliability demonstrated. Formulations for in vivo evaluation of the 3D printed structures were selected on the basis of their in vitro bacterial biofilm inhibitory properties and lack of mammalian cell cytotoxicity. In vivo in a mouse implant infection model, Pseudomonas aeruginosa biofilm formation on poly-TCDMDA was reduced by ∼99% when compared with medical grade silicone. Whole mouse bioluminescence imaging and tissue immunohistochemistry revealed the ability of the printed device to modulate host immune responses as well as preventing biofilm formation on the device and infection of the surrounding tissues. Since 3D printing can be used to manufacture devices for both prototyping and clinical use, the versatility of ink-jet based 3D-printing to create personalised functional medical devices is demonstrated by the biofilm resistance of both a finger joint prosthetic and a prostatic stent printed in poly-TCDMDA towards P. aeruginosa and Staphylococcus aureus.}, } @article {pmid35033514, year = {2022}, author = {Cao, L and Zhu, G and Tao, J and Zhang, Y}, title = {Iron carriers promote biofilm formation and p-nitrophenol degradation.}, journal = {Chemosphere}, volume = {293}, number = {}, pages = {133601}, doi = {10.1016/j.chemosphere.2022.133601}, pmid = {35033514}, issn = {1879-1298}, mesh = {Biofilms ; *Iron ; Nitrophenols/metabolism ; *Water Pollutants, Chemical/analysis ; }, abstract = {Vertical baffled biofilm reactors (VBBR) equipped with Plastic-carriers and Fe-carriers were employed to explore the effect of biofilm carriers on biofilm formation and p-nitrophenol (PNP) degradation. The results showed that Fe-carriers enhanced biofilm formation and PNP degradation. The maximum thickness of biofilm grown on the Fe-carriers was 1.5-fold higher than that on the Plastic-carriers. The Fe-VBBR reached a maximum rate of PNP removal at 13.02 μM L[-1] h[-1] with less sodium acetate addition (3 mM), while the maximum rate of PNP removal was 11.53 μM L[-1] h[-1] with more sodium acetate addition (6 mM) in the Plastic-based VBBR. High-throughput sequencing suggested that the Fe-VBBR had a higher biodiversity of the bacterial community in evenness, and the Achromobacter genus and Xanthobacteraceae family were as main PNP degraders. Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology analysis suggested more abundances of iron uptake genes were expressed to transport iron into the cytoplasm under an iron-limited condition in two VBBRs, and the metabolic pathway of PNP degradation went through 4-nitrocatechol and 1,2,4-benzenetriol. Our results provide a new insight for iron enhancing biofilm formation and PNP degradation.}, } @article {pmid35032606, year = {2022}, author = {Tatta, ER and Kumavath, R}, title = {Attenuation of Enterococcus faecalis biofilm formation by Rhodethrin: A combinatorial study with an antibiotic.}, journal = {Microbial pathogenesis}, volume = {163}, number = {}, pages = {105401}, doi = {10.1016/j.micpath.2022.105401}, pmid = {35032606}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins ; Biofilms ; *Enterococcus faecalis ; *Vancomycin-Resistant Enterococci ; }, abstract = {The nosocomial pathogen Enterococcus faecalis critically implicated in the hospital environment. Its major virulence attributes biofilm formation and antibiotic resistance. The novel therapeutics are required to inhibit E. faecalis biofilm formation and virulence. Thus combinatorial and drug repurposing has been promising approaches to tackling biofilm-associated infections. Here, we have used a bacterium that produced indole terpenoid Rhodethrin (Rdn) with a combination of known antibiotic chloramphenicol (Chpl) against E. faecalis (ATCC 19433). The fractional inhibitory concentration index (FICI) values showed between 0.25 and 0.33 synergistic activities. The exopolysaccharides (EPSs) production significant decrease with Rdn (34.6 ± 4.6%), Chpl (31.0 ± 5.2%), and combination (Rdn-Chpl) (76.0 ± 4.5%) (p > 0.05). However, the biofilm interruption can attenuate of total biofilm was shown with Rdn (39.7 ± 5.1%), Chpl (32.6 ± 4.7%), and Rdn-Chpl (69.0 ± 5.3%), (p > 0.05). The microscopic observations reveal that the gradually unstructured biofilm architecture in E. faecalis. Furthermore, in silico, studies on biofilm-associated proteins (GelE, LuxS), virulence regulating (SprE), and cell division (FtsZ) have resulted in high and reasonable binding affinity, respectively. Thus, our results suggested that the synergism of Rdn-Chpl has the potential to function as a combinatorial antibiotic accelerates in treating vancomycin-resistant Enterococcus faecalis infections.}, } @article {pmid35032513, year = {2022}, author = {Ahmed, B and Jailani, A and Lee, JH and Lee, J}, title = {Effect of halogenated indoles on biofilm formation, virulence, and root surface colonization by Agrobacterium tumefaciens.}, journal = {Chemosphere}, volume = {293}, number = {}, pages = {133603}, doi = {10.1016/j.chemosphere.2022.133603}, pmid = {35032513}, issn = {1879-1298}, mesh = {*Agrobacterium tumefaciens/genetics/metabolism ; Bacterial Proteins/genetics ; *Biofilms ; Indoles/pharmacology ; Virulence/genetics ; }, abstract = {Agrobacterium tumefaciens is a plant pathogen that causes crown gall disease in several plant species by transferring its T-DNA to the host genome. Its chemotactic response to a range of chemical compounds released by hosts facilitates its colonization to host surfaces, and thus, novel anti-agrobacterium compounds are needed to prevent its biofilm formation. Here, we investigated 83 indole derivatives against A. tumefaciens, and based on the screening, 4-chloroindole, 6-iodoindole, and 5-chloro-2-methyl indole were selected as candidates that at 50 μg mL[-1] significantly inhibited the adherence and biofilm formation of A. tumefaciens to abiotic (nitrocellulose and polystyrene) and biotic (roots of Brassica juncea) surfaces. Furthermore, they reduced bacterial growth in a time and concentration-dependent manner and significantly reduced log CFU mL[-1] and survival (%). Changes in biofilm morphologies and biomasses, thicknesses, and substratum coverages were determined, and 2-D and 3-D analyses were performed using a crystal violet assay and bright field, CLSM, and SEM microscopies. Virulence factors such as swimming motility, exopolysaccharide, and exo-protease production, and cell surface hydrophobicity were markedly inhibited by the three compounds. Transcriptional analysis showed multi-fold downregulation of biofilm, virulence, motility, and stress-related genes; however, the degrees of these downregulations were variably affected. B. juncea seed germination was only severely affected by 4-chloroindole. This study demonstrates the promising antibiofilm and antivirulence activities of the three indole derivatives tested and their potentials for targeting and curbing A. tumefaciens infections.}, } @article {pmid35032186, year = {2022}, author = {Klein, E and Weiler, J and Wagner, M and Čelikić, M and Niemeyer, CM and Horn, H and Gescher, J}, title = {Enrichment of phosphate-accumulating organisms (PAOs) in a microfluidic model biofilm system by mimicking a typical aerobic granular sludge feast/famine regime.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {3}, pages = {1313-1324}, pmid = {35032186}, issn = {1432-0614}, mesh = {Biofilms ; Bioreactors ; In Situ Hybridization, Fluorescence ; *Microfluidics ; Phosphorus ; Polyphosphates ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {Wastewater treatment using aerobic granular sludge has gained increasing interest due to its advantages compared to conventional activated sludge. The technology allows simultaneous removal of organic carbon, nitrogen, and phosphorus in a single reactor system and is independent of space-intensive settling tanks. However, due to the microscale, an analysis of processes and microbial population along the radius of granules is challenging. Here, we introduce a model system for aerobic granular sludge on a small scale by using a machine-assisted microfluidic cultivation platform. With an implemented logic module that controls solenoid valves, we realized alternating oxic hunger and anoxic feeding phases for the biofilms growing within. Sampling during ongoing anoxic cultivation directly from the cultivation channel was achieved with a robotic sampling device. Analysis of the biofilms was conducted using optical coherence tomography, fluorescence in situ hybridization, and amplicon sequencing. Using this setup, it was possible to significantly enrich the percentage of polyphosphate-accumulating organisms (PAO) belonging to the family Rhodocyclaceae in the community compared to the starting inoculum. With the aid of this miniature model system, it is now possible to investigate the influence of a multitude of process parameters in a highly parallel way to understand and efficiently optimize aerobic granular sludge-based wastewater treatment systems.Key points• Development of a microfluidic model to study EBPR.• Feast-famine regime enriches polyphosphate-accumulating organisms (PAOs).• Microfluidics replace sequencing batch reactors for aerobic granular sludge research.}, } @article {pmid35032112, year = {2022}, author = {Louis, M and Clamens, T and Tahrioui, A and Desriac, F and Rodrigues, S and Rosay, T and Harmer, N and Diaz, S and Barreau, M and Racine, PJ and Kipnis, E and Grandjean, T and Vieillard, J and Bouffartigues, E and Cornelis, P and Chevalier, S and Feuilloley, MGJ and Lesouhaitier, O}, title = {Pseudomonas aeruginosa Biofilm Dispersion by the Human Atrial Natriuretic Peptide.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {9}, number = {7}, pages = {e2103262}, pmid = {35032112}, issn = {2198-3844}, support = {//Region Normandy, the InterReg IVA PeReNE project and from the Normandy Valorisation cluster/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Atrial Natriuretic Factor/metabolism/pharmacology ; Biofilms ; Humans ; *Pseudomonas aeruginosa/metabolism ; Virulence ; }, abstract = {Pseudomonas aeruginosa biofilms cause chronic, antibiotic tolerant infections in wounds and lungs. Numerous recent studies demonstrate that bacteria can detect human communication compounds through specific sensor/receptor tools that modulate bacterial physiology. Consequently, interfering with these mechanisms offers an exciting opportunity to directly affect the infection process. It is shown that the human hormone Atrial Natriuretic Peptide (hANP) both prevents the formation of P. aeruginosa biofilms and strongly disperses established P. aeruginosa biofilms. This hANP action is dose-dependent with a strong effect at low nanomolar concentrations and takes effect in 30-120 min. Furthermore, although hANP has no antimicrobial effect, it acts as an antibiotic adjuvant. hANP enhances the antibiofilm action of antibiotics with diverse modes of action, allowing almost full biofilm eradication. The hANP effect requires the presence of the P. aeruginosa sensor AmiC and the AmiR antiterminator regulator, indicating a specific mode of action. These data establish the activation of the ami pathway as a potential mechanism for P. aeruginosa biofilm dispersion. hANP appears to be devoid of toxicity, does not enhance bacterial pathogenicity, and acts synergistically with antibiotics. These data show that hANP is a promising powerful antibiofilm weapon against established P. aeruginosa biofilms in chronic infections.}, } @article {pmid35031974, year = {2022}, author = {Kütük, D and Temiz, A}, title = {Biofilm formation potential of Bacillus toyonensis and Pseudomonas aeruginosa on the stainless steel test surfaces in a model dairy batch system.}, journal = {Folia microbiologica}, volume = {67}, number = {3}, pages = {405-417}, pmid = {35031974}, issn = {1874-9356}, mesh = {Bacillus ; Bacterial Adhesion ; Biofilms ; *Pseudomonas aeruginosa ; *Stainless Steel ; }, abstract = {Bacillus toyonensis (a Gram-positive bacterium) and Pseudomonas aeruginosa (a Gram-negative bacterium) isolated from the different surfaces of a dairy plant in our previous study were selected as the test bacteria for the present study. These two test bacteria were investigated in terms of their attachment on the stainless steel test surfaces in a model dairy batch system. After incubation at 5 °C and 20 °C for 6 h, 12 h, and 24 h, stainless steel plates were examined using cultural counts, profilometer, scanning electron microscopy (SEM), and fluorescent microscopy. Also, the test plates were subjected to a cleaning/disinfection procedure used in the dairy plant. Tests were employed before and after the cleaning/disinfection procedures. Cell wall characteristics and holding temperature were found to be significant for the attachment of the test bacteria to stainless steel test surfaces. In the study, the effect of the holding temperature varied depending on the type and characteristics of the bacteria. The adhesion ability of P. aeruginosa was higher than that of B. toyonensis. Increases in the holding temperature may increase the adhesion ability of the bacteria. Milk growth medium was found to be more successful in preventing the attachment ability of P. aeruginosa compared to B. toyonensis. This indicates that the chemical characteristic of the contact material may affect adhesion. The adhered bacterial cells were entirely removed by means of the cleaning/disinfection treatment. Therefore, the adhesion of bacterial cells could be explained as "initial phase of biofilm formation." It can be concluded that the microorganism cell adhesion on the surface is followed by biofilm formation, and this situation lasts for many years. These results reveal the importance of controlling biofilm formation in dairy plants from the beginning.}, } @article {pmid35030488, year = {2022}, author = {Zhang, R and Ali, A and Su, J and Liu, J and Wang, Z and Li, J and Liu, Y}, title = {Synergistic removal of fluoride, calcium, and nitrate in a biofilm reactor based on anaerobic microbially induced calcium precipitation.}, journal = {Journal of hazardous materials}, volume = {428}, number = {}, pages = {128102}, doi = {10.1016/j.jhazmat.2021.128102}, pmid = {35030488}, issn = {1873-3336}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Calcium ; Calcium Fluoride ; Denitrification ; *Fluorides ; *Nitrates ; }, abstract = {Fluoride (F[-]) and calcium (Ca[2+]) are primary causes of skeleton fluorosis and scaling, posing a grievous threat to aquatic lives and public health. Therefore, a novel strategy for polluted groundwater in immobilized biofilm reactor based on the anaerobic microbial induced calcium precipitation (MICP) was proposed, in which loofah was used as a multifunctional strain Cupriavidus sp. W12 growth carrier. Effects of different hydraulic retention time (HRT), initial F[-]concentration, and pH on the synchronous removal of pollutants were examined. Under stable operation conditions, the highest efficiencies for Ca[2+], F[-], and nitrate (NO3[-]-N) reached 76.73%, 94.92%, and 100%, respectively. Furthermore, gas chromatography (GC), Fluorescence excitation-emission matrix (EEM), X-ray diffraction (XRD), Scanning electron microscope-energy dispersive spectroscope (SEM-EDS), and Fourier transform infrared spectrometer (FTIR) comprehensively clarified the mechanism of pollutants removal. The results elucidated that the removal of various pollutants was achieved through a combination of anaerobic MICP, adsorption, and co-precipitation. Besides, high-throughput sequencing analysis showed that Cupriavidus had a predominant proportion of 42.36% in the reactor and had stability against pH impact. As the first application of a biofilm reactor based on anaerobic MICP, it put forward a new insight for efficient defluorination and decalcification.}, } @article {pmid35030360, year = {2022}, author = {Wang, S and Xu, M and Jin, B and Wünsch, UJ and Su, Y and Zhang, Y}, title = {Electrochemical and microbiological response of exoelectrogenic biofilm to polyethylene microplastics in water.}, journal = {Water research}, volume = {211}, number = {}, pages = {118046}, doi = {10.1016/j.watres.2022.118046}, pmid = {35030360}, issn = {1879-2448}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Microplastics ; Plastics ; Polyethylene ; }, abstract = {Exoelectrogenic biofilm and the associated microbial electrochemical processes have recently been intensively studied for water treatment, but their response to and interaction with polyethylene (PE) microplastics which are widespread in various aquatic environments has never been reported. Here, we investigated how and to what extent PE microplastics would affect the electrochemistry and microbiology of exoelectrogenic biofilm in both microbial fuel cells (MFCs) and microbial electrolysis cells (MECs). When the PE microplastics concentration was increased from 0 to 75 mg/L in the MECs, an apparent decline in the maximum current density (from 1.99 to 0.74 A/m[2]) and abundance of electroactive bacteria (EAB) in the exoelectrogenic biofilm was noticed. While in the MFCs, the current output was not significantly influenced and the abundance of EAB lightly increased at 25 mg/L microplastics. In addition, PE microplastics restrained the viability of the exoelectrogenic biofilms in both systems, leading to a higher system electrode resistance. Moreover, the microbial community richness and the microplastics-related operational taxonomic units decreased with PE microplastics. Furthermore, the electron transfer-related genes (e.g., pilA and mtrC) and cytochrome c concentration decreased after adding microplastics. This study provides the first glimpse into the influence of PE microplastics on the exoelectrogenic biofilm with the potential mechanisms revealed at the gene level, laying a methodological foundation for the future development of efficient water treatment technologies.}, } @article {pmid35028576, year = {2022}, author = {You, R and Kwon, OY and Woo, HJ and Lee, SH}, title = {Hovenia Monofloral Honey can Attenuate Enterococcus faecalis Mediated Biofilm Formation and Inflammation.}, journal = {Food science of animal resources}, volume = {42}, number = {1}, pages = {84-97}, pmid = {35028576}, issn = {2636-0780}, abstract = {We evaluated the anti-biofilm formation and anti-inflammatory activity of Hovenia monofloral honey (HMH) against Enterococcus faecalis. Co-culture of HMH with E. faecalis attenuated the biofilm formation of E. faecalis on a polystyrene surface. In addition, HMH effectively eradicated the established E. faecalis biofilm. HMH significantly attenuated E. faecalis growth but did not affect the production of extracellular polymeric substances on E. faecalis, indicating that reduction of E. faecalis biofilm is a result of HMH-mediated killing of E. faecalis. Furthermore, we found that HMH can effectively attenuate E. faecalis-induced expression of a proinflammatory interleukin-8 (IL-8) in HT-29 cells. Interestingly, treatment of HMH significantly attenuated the E. faecalis-mediated expression of Toll-like receptor-2 (TLR-2) and its adaptor molecules, myeloid differentiation primary response 88 (MyD88), in HT-29 cells. In addition, E. faecalis-induced mitogen-activated protein kinases (MAPKs) phosphorylation was significantly attenuated by HMH administration. Furthermore, HMH-mediated anti-inflammatory efficacy (0.2 mg/mL of HMHs) had an equal extent of inhibitory efficacy as 5 μM of MyD88 inhibitor to attenuate E. faecalis-mediated IL-8 expression in HT-29 cells. These results suggest that HMH could effectively inhibit E. faecalis-mediated gastrointestinal inflammation through regulating the TLR-2/MyD88/MAPKs signaling pathways. Collectively, our data suggest that HMH could be developed as a potential natural agent to control E. faecalis-mediated biofilm formation and inflammation.}, } @article {pmid35028283, year = {2022}, author = {El-Telbany, M and El-Sharaki, A}, title = {Antibacterial and anti-biofilm activity of silver nanoparticles on multi-drug resistance pseudomonas aeruginosa isolated from dental-implant.}, journal = {Journal of oral biology and craniofacial research}, volume = {12}, number = {1}, pages = {199-203}, pmid = {35028283}, issn = {2212-4268}, abstract = {AIM: The aim of this study was to isolate multi-drug-resistant p. aeruginosa from dental implant, and control the growth and biofilm of isolated p. aeruginosa by silver nanoparticles.

MATERIALS AND METHODS: Thirty specimens from patients with Peri-implantitis were taken for isolation of p. aeruginosa. Bacterial samples were obtained from the infected peri-implant pocket with sterile paper points (size 30-45 mm). Samples were cultured for isolation of Multi-drug resistance P. aeruginosa. Phenotypical identification was done by the VITEK 2 system. DNA was extracted from the isolates and 16S rDNA-based PCR assay was used to confirm the identification. Susceptibility of isolated p. aeruginosa to 16 antibiotics was evaluated using the VITEK 2 system. The growth inhibition of isolated bacteria by AgNPs was tested by disk-diffusion method. The microtiter plate assay was used to estimate the capacity of P. aeruginosa to from biofilms. Antibiofilm activity of AgNPs was determined by microtiter plate assay.

RESULTS: Three P. aeruginosa were successfully isolated from 30 clinical specimens. P. aeruginoas isolates were resistance to most of used antibiotics. Silver nanoparticles exerted an inhibitory effect on all isolated bacteria. All tested concentration of AgNPS exhibited a greatest anti-biofilm activity against multi-drug resistance (MDR) p. aeruginosa.

CONCLUSION: Current findings highlight the role of AgNPS in growth inhibition of P. aeruginosa and reveal a potential application of AgNPS in eradication of p. aeruginosa biofilms.}, } @article {pmid35424252, year = {2021}, author = {Dostert, M and Trimble, MJ and Hancock, REW}, title = {Antibiofilm peptides: overcoming biofilm-related treatment failure.}, journal = {RSC advances}, volume = {11}, number = {5}, pages = {2718-2728}, pmid = {35424252}, issn = {2046-2069}, abstract = {Health leaders and scientists worldwide consider antibiotic resistance among the world's most dangerous pathogens as one of the biggest threats to global health. Antibiotic resistance has largely been attributed to genetic changes, but the role and recalcitrance of biofilms, largely due to growth state dependent adaptive resistance, is becoming increasingly appreciated. Biofilms are mono- and multi-species microbial communities embedded in an extracellular, protective matrix. In this growth state, bacteria are transcriptionally primed to survive extracellular stresses. Adaptations, affecting metabolism, regulation, surface charge, immune recognition and clearance, allow bacteria to thrive in the human body and withstand antibiotics and the host immune system. Biofilms resist clearance by multiple antibiotics and have a major role in chronic infections, causing more than 65% of all infections. No specific antibiofilm agents have been developed. Thus, there is a pressing need for alternatives to traditional antibiotics that directly inhibit and/or eradicate biofilms. Host defence peptides (HDPs) are small cationic peptides that are part of the innate immune system to both directly kill microbes but also function to modulate the immune response. Specific HDPs and their derivatives demonstrate broad-spectrum activity against biofilms. In vivo biofilm assays show efficacy in abscess, respiratory, in-dwelling device, contact lens and skin infection models. Further progress has been made through the study of ex vivo organoid and air-liquid interface models to better understand human infections and treatment while relieving the burden and complex nature of animal models. These avenues pave the way for a better understanding and treatment of the underlying cause of chronic infections that challenge the healthcare system.}, } @article {pmid35424119, year = {2021}, author = {Manoharadas, S and Altaf, M and Alrefaei, AF and Devasia, RM and Badjah Hadj, AYM and Abuhasil, MSA}, title = {Concerted dispersion of Staphylococcus aureus biofilm by bacteriophage and 'green synthesized' silver nanoparticles.}, journal = {RSC advances}, volume = {11}, number = {3}, pages = {1420-1429}, pmid = {35424119}, issn = {2046-2069}, abstract = {Staphylococcal biofilms predominantly cause persistent nosocomial infections. The widespread antibiotic resistance followed by its ability to form biofilm in biological and inert surfaces often contributes to major complications in patients and veterinary animals. Strategic importance of bacteriophage therapy against critical staphylococcal infections had been predicted ever since the advent of antibiotic resistant staphylococcal strains. The significance of metal nanoparticles in quenching biofilm associated bacteria was previously reported. In this study, we demonstrate a concerted action of 'green synthesized' silver nanoparticles and bacteriophages in removing pre-formed Staphylococcus aureus biofilms from an inert glass surface in a time dependent manner. Our results demonstrate, for the first time, the rapid co-operative dispersion of the bacterial biofilm. In addition, the synergistic activity of the nanoparticles and bacteriophages causes the loss of viability of the biofilm entrapped bacterial cells thus preventing establishment of a new infection and subsequent colonization. This work further opens up a platform for the combinational therapeutic approach with a variety of nanoparticles and bacteriophages against mono or poly bacterial biofilm in environmental, industrial or clinical settings.}, } @article {pmid35559767, year = {2021}, author = {Hou, Y and Yang, M and Li, J and Bi, X and Li, G and Xu, J and Xie, S and Dong, Y and Li, D and Du, Y}, title = {The enhancing antifungal effect of AD1 aptamer-functionalized amphotericin B-loaded PLGA-PEG nanoparticles with a low-frequency and low-intensity ultrasound exposure on C.albicans biofilm through targeted effect.}, journal = {NanoImpact}, volume = {21}, number = {}, pages = {100275}, doi = {10.1016/j.impact.2020.100275}, pmid = {35559767}, issn = {2452-0748}, mesh = {*Amphotericin B/pharmacology ; Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; *Nanoparticles/therapeutic use ; Polylactic Acid-Polyglycolic Acid Copolymer/pharmacology ; }, abstract = {The prevalence and fatality rates with fungal biofilm-associated infections urgently need to develop targeted therapeutic approaches to augment the action of antifungal drugs. This study developed amphotericin B-loaded PLGA-PEG nanoparticles (AmB-NPs) with AD1 aptamer conjugation on its surface via an EDC/NHS technique. Their high nuclease resistance of the conjugation was confirmed by PAGE gel electrophoresis. The targeting and toxicity of AD1-AmB-NPs in the subcutaneous C. albicans infection model were evaluated. AD1-AmB-NPs can bind to different morphological forms(including yeast cells, germ tubes, hyphae) of C. albicans biofilms and extracellular matrix material. Low-frequency and low-intensity ultrasound (LFU, with a fixed frequency of 42 kHz, at the intensity of 0.30 W/cm[2] for 15 min) significantly promoted permeability of the biofilm and allowed AD1-AmB-NPs into the deepest layers of the biofilm. After 7 days of treatment, the combination treatment of AD1-AmB-NPs and LFU, kills at least 99% of the biofilm fungal population in vivo comparison with ultrasound alone or AD1-AmB-NPs alone, and returned to normal subcutaneously. Our data suggest that the combined strategy of AD1-AmB-NPs and ultrasound treatment selective delivered of therapeutic drugs to the infection site and exhibited significant synergistic antifungal effects.}, } @article {pmid35520668, year = {2020}, author = {Eduok, U and Szpunar, J}, title = {In vitro corrosion studies of stainless-steel dental substrates during Porphyromonas gingivalis biofilm growth in artificial saliva solutions: providing insights into the role of resident oral bacterium.}, journal = {RSC advances}, volume = {10}, number = {52}, pages = {31280-31294}, pmid = {35520668}, issn = {2046-2069}, abstract = {Stainless-steel AISI 321 is an effective material for fabricating dental crowns and other implants utilized dental restorative protocols for elderly and pediatric populations. This unique clinical application is possible through the mechanical stability and corrosion-resistance properties of this metallic material. However, stainless-steel dental implants eventually fail, leading to the creation of surface cavities and cracks within their microstructures during persistent mechanical stresses and biocorrosion. In this study, the in vitro corrosion behaviour of a medical-grade stainless-steel dental substrate was investigated during Porphyromonas gingivalis biofilm growth process in artificial saliva culture suspension (ASCS). Among the causative bioagents of corrosion, P. gingivalis was chosen for this study since it is also responsible for oral periodontitis and a major contributing factor to corrosion in most dental implants. Increased P. gingivalis growth was observed within the incubation period under study as compact cellular clusters fouled the metal surfaces in ASCS media. This led to the corrosion of steel substrates after bacterial growth maturity within 90 days. Corrosion rate increased with higher CFU and bacterial incubation period for all test substrates due to biocorrosion incited by the volatile sulphide products of P. gingivalis metabolism. The presence of some of these volatile compounds has been observed from experimental evidences. Significant anodic degradation in the forms of localized pitting were also recorded by surface analytical techniques. Residual fluorinated ions within the ASCS media also increased the rate of anodic dissolution due to media acidity. This study has provided extensive insights into the fate of stainless-steel dental crown in oral environments infected by a resident oral bacterium. Influences of oral conditions similar to fluoride-enriched mouthwashes were reflected in a view to understanding the corrosion patterns of stainless-steel dental substrates.}, } @article {pmid35520667, year = {2020}, author = {Zhu, Z and Shan, L and Hu, F and Li, Z and Zhong, D and Yuan, Y and Zhang, J}, title = {Biofilm formation potential and chlorine resistance of typical bacteria isolated from drinking water distribution systems.}, journal = {RSC advances}, volume = {10}, number = {52}, pages = {31295-31304}, pmid = {35520667}, issn = {2046-2069}, abstract = {Biofilms are the main carrier of microbial communities throughout drinking water distribution systems (DWDSs), and strongly affect the safety of drinking water. Understanding biofilm formation potential and chlorine resistance is necessary for exploring future disinfection strategies and preventing water-borne diseases. This study investigated biofilm formation of five bacterial strains isolated from a simulated DWDS at different incubation times (24 h, 48 h, and 72 h), then evaluated chlorine resistance of 72 h incubated biofilms under chlorine concentrations of 0.3, 0.6, 1, 2, 4, and 10 mg L[-1]. All five bacterial strains had biofilm formation potential when incubated for 72 h. The biofilm formation potential of Acinetobacter sp. was stronger than that of Bacillus cereus, Microbacterium sp. and Sphingomonas sp. were moderate, and that of Acidovorax sp. was weak. In contrast, the order of chlorine resistance was Bacillus sp. > Sphingomonas sp. > Microbacterium sp. > Acidovorax sp. > Acinetobacter sp. Thus, the chlorine resistance of a single-species biofilm has little relation with the biofilm formation potential. The biofilm biomass is not a major factor affecting chlorine resistance. Moreover, the chlorine resistance of a single-species biofilm is highly related to the physiological state of bacterial cells, such as their ability to form spores or secrete extracellular polymeric substances, which could reduce the sensitivity of the single-species biofilm to a disinfectant or otherwise protect the biofilm.}, } @article {pmid35520069, year = {2020}, author = {Sun, Z and Li, M and Wang, G and Yan, X and Li, Y and Lan, M and Liu, R and Li, B}, title = {Enhanced carbon and nitrogen removal in an integrated anaerobic/anoxic/aerobic-membrane aerated biofilm reactor system.}, journal = {RSC advances}, volume = {10}, number = {48}, pages = {28838-28847}, pmid = {35520069}, issn = {2046-2069}, abstract = {A pilot-scale anaerobic/anoxic/aerobic-membrane aerated biofilm reactor (A[2]/O-MABR) system was constructed to enhance carbon and nitrogen removal. The effects of major operating parameters including the nitrate recycling ratio (R), sludge recycling ratio (r), and aerobic tank dissolved oxygen (DO) concentration on the system performance were investigated. The average removal efficiencies of the chemical oxygen demand (COD), ammonium nitrogen (NH4 [+]-N), and total nitrogen (TN) were 89.0 ± 3.2%, 98.8 ± 1.3%, and 68.5 ± 4.2%, respectively, and their effluent concentrations were averagely 22.6 ± 7.3, 0.32 ± 0.2, and 13.3 ± 1.2 mg L[-1]. The suspended sludge and biofilm in aerobic tank facilitated the simultaneous nitrification and denitrification (SND) processes. Indeed, unique biofilm layered structure and abundant microbial community in the biofilm on MABR would enhance nitrogen removal. Compared with the A[2]/O system, the A[2]/O-MABR system exhibited higher nitrifying bacteria oxygen uptake rate (OUR) of 58.1 and 54.5 mgO2 per gMLSS per h in suspended sludge and biofilm, respectively, and the lower mixed liquor suspended solid (MLSS) concentration of 1800 mg L[-1]. Moreover, high-throughput sequencing indicated that putative nitrogen removal bacteria such as Thauera and Paracoccus could be effectively enriched in the biofilm. Since the volume proportions of the anaerobic, anoxic, aerobic and settling tank in the existing A[2]/O system of the WWTP was not changed, the A[2]/O-MABR system was simple and practical for the upgrading of A[2]/O system.}, } @article {pmid35517329, year = {2020}, author = {Khatoon, Z and Guzmán-Soto, I and McTiernan, CD and Lazurko, C and Simpson, F and Zhang, L and Cortes, D and Mah, TF and Griffith, M and Alarcon, EI}, title = {Nanoengineering the surface of corneal implants: towards functional anti-microbial and biofilm materials.}, journal = {RSC advances}, volume = {10}, number = {40}, pages = {23675-23681}, pmid = {35517329}, issn = {2046-2069}, abstract = {We report the development and use of a light-mediated in situ grafting technology for the surface modification of biosynthetic corneal implants with peptide-capped nanoparticles (15-65 nm). The resulting materials have antimicrobial properties in bacterial suspension and also reduced the extent of biofilm formation. Our in situ grafting technology offers a rapid route for the introduction of antimicrobial properties to premoulded corneal implants, and potentially other soft implant targets.}, } @article {pmid35515581, year = {2020}, author = {Lu, X and Zhang, Z and Xu, Y and Lu, J and Tang, W and Zhang, J}, title = {Effect of new carbonyl cyanide aromatic hydrazones on biofilm inhibition against methicillin resistant Staphylococcus aureus.}, journal = {RSC advances}, volume = {10}, number = {30}, pages = {17854-17861}, pmid = {35515581}, issn = {2046-2069}, abstract = {Carbonyl cyanide m-chlorophenylhydrazone (CCCP), as a protonophore, in combination with antibiotics exhibited potentiating antibacterial activity. To improve CCCP's potency and toxicity, a series of aromatic hydrazones were synthesized and their antimicrobial activity was evaluated; amongst them, compounds 2e and 2j with a strong para-electron-withdrawing substituent (-NO2 and -CF3) at the phenyl ring had the lowest MICs against both S. aureus and methicillin resistant Staphylococcus aureus (1.56 and 1.56 μM, respectively). Some compounds in combination with antibiotics exhibited potentiate Gram-positive antibacterial activity; compound 2e was found to display unaided or synergistic efficacy against MRSA. In particular, when compound 2e is combined with ofloxacin, it has a good synergistic effect against MRSA. Moreover, electron microscopy revealed that compound 2e inhibits biofilm formation and effectively eradicates preformed biofilm. MTT assay showed that compound 2e displays as low toxicity as CCCP. Overall, our data showed that the aromatic hydrazone is a promising scaffold for anti-staphylococcal drug development.}, } @article {pmid35492176, year = {2020}, author = {Liu, B and Zhan, H and Lu, X and Liu, Y and Huang, L and Wei, Z}, title = {Biodegradation of carbon tetrachloride from groundwater in an upflow solid-phase biofilm system.}, journal = {RSC advances}, volume = {10}, number = {13}, pages = {7500-7508}, pmid = {35492176}, issn = {2046-2069}, abstract = {In the present study, an upflow solid-phase denitrification biofilm reactor (US-DBR) was applied for simultaneous carbon tetrachloride (CT) and nitrate removal from groundwater by using poly(butylene succinate) (PBS) as carbon source and biocarrier. After 80 days continuous operation, the nitrate and CT removal efficiencies in the biofilm reactor were high of 98% and 94.3%, respectively. After PBS-biofilm formation, protein (PN) content in loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) significantly increased 2.6 and 4.0 times higher in the presence of CT than those of absence of CT, while PS increased 1.9 and 2.0 times higher. According to excitation-emission matrix (EEM), CT exposure contributed to the increased fluorescent intensities of the aromatic PN-like and tryptophan PN-like substances. Along with the height of US-DBR, the denitrification activity was inhibited by the CT exposure, and most of CT was significant transformed accompanied by nitrate removal. Two components of soluble microbial products (SMP) were identified, including humic-like substances for component 1 and PN-like substances for component 2, respectively. It was found from high-throughput 16S rRNA gene sequencing analysis that significant differences were observed at genus level by taxonomic assignments to CT exposure. Thiobacillus, Thauera, Candidatus_Competibacter and Hydrogenophaga were the main genus in the presence of CT at the proportion of 6.77%, 5.47%, 3.59% and 3.17%, respectively.}, } @article {pmid35492196, year = {2020}, author = {Michl, TD and Tran, DTT and Kuckling, HF and Zhalgasbaikyzy, A and Ivanovská, B and González García, LE and Visalakshan, RM and Vasilev, K}, title = {It takes two for chronic wounds to heal: dispersing bacterial biofilm and modulating inflammation with dual action plasma coatings.}, journal = {RSC advances}, volume = {10}, number = {13}, pages = {7368-7376}, pmid = {35492196}, issn = {2046-2069}, abstract = {Chronic wounds are affecting increasingly larger portions of the general population and their treatment has essentially remained unchanged for the past century. This lack of progress is due to the complex problem that chronic wounds are simultaneously infected and inflamed. Both aspects need to be addressed together to achieve a better healing outcome. Hence, we hereby demonstrate that the stable nitroxide radical (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) can be plasma polymerized into smooth coatings (TEMPOpp), as seen via atomic force microscopy, X-ray photoelectron spectroscopy and ellipsometry. Upon contact with water, these coatings leach nitroxides into aqueous supernatant, as measured via EPR. We then exploited the known cell-signalling qualities of TEMPO to change the cellular behaviour of bacteria and human cells that come into contact with the surfaces. Specifically, the TEMPOpp coatings not only suppressed biofilm formation of the opportunistic bacterium Staphylococcus epidermidis but also dispersed already formed biofilm in a dose-dependent manner; a crucial aspect in treating chronic wounds that contain bacterial biofilm. Thus the coatings' microbiological efficacy correlated with their thickness and the thickest coating was the most efficient. Furthermore, this dose-dependent effect was mirrored in significant cytokine reduction of activated THP-1 macrophages for the four cytokines TNF-α, IL-1β, IL-6 and IP-10. At the same time, the THP-1 cells retained their ability to adhere and colonize the surfaces, as verified via SEM imaging. Thus, summarily, we have exploited the unique qualities of plasma polymerized TEMPO coatings in targeting both infection and inflammation simultaneously; demonstrating a novel alternative to how chronic wounds could be treated in the future.}, } @article {pmid35496022, year = {2020}, author = {Zhang, Q and Zhang, F and Gong, C and Tan, X and Ren, Y and Yao, K and Zhang, Q and Chi, Y}, title = {Physicochemical, microbial, and aroma characteristics of Chinese pickled red peppers (Capsicum annuum) with and without biofilm.}, journal = {RSC advances}, volume = {10}, number = {11}, pages = {6609-6617}, pmid = {35496022}, issn = {2046-2069}, abstract = {Biofilm formation in the production of fermented vegetable might impact its quality and safety. In this study, physicochemical and microbial properties, volatile and aroma-active compounds between PRPs without biofilm (NPRP) and with biofilm (FPRP) were investigated by gas chromatography-mass spectrometry, gas chromatography-olfactometry, aroma extract dilution analysis, and spiking tests. The pH and titratable acidity were 3.66 ± 0.00 and 0.47 ± 0.08 g/100 g lactic acid in NPRP and 3.48 ± 0.01 and 0.87 ± 0.10 g/100 g lactic acid in FPRP, respectively. The nitrite level of the two PRPs was 1.87-1.92 mg kg[-1], which was below the limited value (20 mg kg[-1]) of fermented vegetables regulated by the GB2760-2017. FPRP had relatively higher microbial and yeast numbers than NPRP, three common pathogens, namely, Salmonella spp., Staphylococcus aureus, and Shigella spp. were not detected. A total of 70 and 151 aroma compounds were detected in NPRP and FPRP, respectively, including 13 classes of compounds. The dominant aroma attributes of FPRP were sour, floral, mushroom-like, green, and smoky, while NPRP exhibits a mushroom-like flavor. Acetic acid, ethanol, α-terpineol, (E)-2-nonenal, 2-heptanol, phenylethyl alcohol, and linalool were potent key aroma-active compounds in NPRP and FPRP. Results of spiking tests showed that the addition of each substance not only increased its own odour, but also had significant effects on other smells. FPRP displayed richer varieties and contents of aroma profile than NPRP. However, some compounds, such as 4-ethylguaiacol and 4-vinylguaiacol, which were only detected in FPRP, had negative roles on the aroma attributes.}, } @article {pmid35529525, year = {2020}, author = {Budge, MD and Koch, JA and Mandell, JB and Cappellini, AJ and Orr, S and Patel, S and Ma, D and Nourie, O and Brothers, KM and Urish, KL}, title = {The In Vitro Efficacy of Doxycycline over Vancomycin and Penicillin in the Elimination of Cutibacterium Acnes Biofilm.}, journal = {Antimicrobial combination devices}, volume = {STP1630}, number = {}, pages = {53-64}, pmid = {35529525}, support = {K08 AR071494/AR/NIAMS NIH HHS/United States ; }, abstract = {Cutibacterium acnes (formerly Propionibacterium acnes) is a significant pathogen in periprosthetic joint infections (PJIs) in total shoulder arthroplasty. Poor outcomes seen in PJIs are due to the established C. acnes bacterial biofilms. The prolonged nature of C. acnes infections makes them difficult to treat with antibiotics. The goal of this study was to determine the relative efficacy of vancomycin compared with penicillin and doxycycline against planktonic and mature biofilms. Clinical isolates from PJI patients as well as a laboratory strain of C. acnes were tested. Planktonic minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were obtained using modified clinical laboratory standard index assays. Biofilm MICs and MBCs were also obtained. The MIC was determined for both using the PrestoBlue viability stain. The MBC was determined using differential reinforced clostridial medium agar plates for colony-forming unit analysis. Using the PrestoBlue viability reagent, the planktonic MIC values for vancomycin were significantly higher than doxycycline. Across 10 strains of C. acnes, all three antibiotics had decreased efficacy when comparing planktonic and biofilm cultures. Although effective antibiotic doses ranged from 1 to 1,000 μg/mL, only doxycycline achieved inhibitory and bactericidal concentrations in all tested strains. Penicillin failed to achieve the minimum biofilm inhibitory concentration (MBIC) in 60% of tested strains, whereas vancomycin failed in 80% of tested strains. Penicillin, doxycycline, and vancomycin have similar abilities in inhibiting C. acnes growth planktonically. The MBIC for doxycycline was within the clinical dosing range, suggesting C. acnes biofilm offers minimal tolerance to these antibiotics. The MBIC for penicillin was within clinical dosing ranges in only 60% of trials, suggesting the relative tolerance of C. acnes to penicillin. The minimum biofilm bactericidal concentration (MBBC) of doxycycline showed efficacy in 90% of trials, whereas penicillin and vancomycin achieved MBBC in 15% of samples.}, } @article {pmid35493534, year = {2020}, author = {Anderson, TM and Shammami, MA and Taddei, SM and Finkel, JS}, title = {How to Use a Mutant Library to Identify Genes Required for Biofilm Formation in the Pathogenic Fungus Candida albicans.}, journal = {UJEMI+}, volume = {2}, number = {}, pages = {1-13}, pmid = {35493534}, support = {RL5 GM118981/GM/NIGMS NIH HHS/United States ; TL4 GM118983/GM/NIGMS NIH HHS/United States ; UL1 GM118982/GM/NIGMS NIH HHS/United States ; }, abstract = {With over 1 billion infections and the causative agents showing critical diseases such as pancreatic cancer, the study of pathogenic fungi has never been more critical. In 2017, the United States spent $7.2 billion on fungal diseases. $4.5 billion was allocated to 75,055 hospitalizations, while $2.6 billion went to 8,993,230 outpatient visits. For Candida infections specifically, the cost was $1.4 billion. Currently, there are few classes of antifungals available, and resistance is growing. The identification of genes required for biofilm formation is essential for new antifungal development. This review details how to identify, verify, and characterize defective biofilm formation mutants in C. albicans. This includes how to run an in vitro biofilm formation assay, how to create clean deletions using the modified CRISPR-Cas9 system, how to assay to identify the potential causes of the defect, and how to create complementation strains to confirm the mutant defect.}, } @article {pmid35540619, year = {2019}, author = {Chen, XR and Liu, YY and Zhou, YH and Xing, XX and Qu, QW and Chen, XY and Ding, WY and Cheng, GL and Wei, AJ and Feng, XW and God'spower, BO and Eliphaz, N and Li, YH}, title = {Process optimization of Syringa oblata Lindl. by response surface methodology and its effect on Staphylococcus xylosus biofilm.}, journal = {RSC advances}, volume = {9}, number = {62}, pages = {36088-36096}, pmid = {35540619}, issn = {2046-2069}, abstract = {Syringa oblata Lindl. (S. oblata) is a medicinal plant with effective broad-spectrum antibacterial activity, which can also inhibit Streptococcus suis biofilm formation. The processing of herbal medicine can purify medicinal materials, provide acceptable taste, reduce toxicity, enhance efficacy, influence performance and facilitate preparation. Thus, the aim of this study was to enhance the biofilm inhibition activity of S. oblata toward Staphylococcus xylosus (S. xylosus) using the best processing method. The content of rutin and flavonoids and the ability to inhibit the biofilm formation by S. oblata were examined using four processing methods. One of the best methods, the process of stir-frying S. oblata with vinegar, was optimized based on the best rutin content by response surface methodology. The histidine content and hisB gene expression of S. xylosus biofilm in vitro, resulting from stir-frying S. oblata with vinegar, were evaluated and were found to be significantly decreased and down-regulated, respectively. The results show that S. oblata stir-fried with vinegar can be used to effectively treat diseases resulting from S. xylosus infection. This is because it significantly inhibited S. xylosus biofilm formation by interfering with the biosynthesis of histidine; thus, its mechanism of action is decreasing histidine synthesis.}, } @article {pmid35529766, year = {2019}, author = {Wu, YP and Liu, XY and Bai, JR and Xie, HC and Ye, SL and Zhong, K and Huang, YN and Gao, H}, title = {Inhibitory effect of a natural phenolic compound, 3-p-trans-coumaroyl-2-hydroxyquinic acid against the attachment phase of biofilm formation of Staphylococcus aureus through targeting sortase A.}, journal = {RSC advances}, volume = {9}, number = {56}, pages = {32453-32461}, pmid = {35529766}, issn = {2046-2069}, abstract = {The antibiofilm activity and molecular mechanism of a natural phenolic compound, 3-p-trans-coumaroyl-2-hydroxyquinic acid (CHQA) against Staphylococcus aureus were investigated in this study. Crystal violet staining and XTT reduction assay demonstrated that CHQA could prominently prevent the biofilm formation of S. aureus accompanied with decrease in metabolic activity of biofilm cells. Meanwhile, microscopic observations revealed that CHQA caused a huge collapse on the architecture of S. aureus biofilm. Moreover, CHQA specifically inhibited the initial attachment phase of biofilm development and reduced S. aureus adhesion to fibrinogen. Fluorescence resonance energy transfer assay and molecular simulation showed that CHQA inhibited the activity of S. aureus sortase A (SrtA) through binding to the active region via non-covalent interactions. Additionally, CHQA efficiently reduced S. aureus attachment to stainless steel. Hence, these results suggested CHQA as a potential bacterial biofilm inhibitor which achieved antibiofilm activity through affecting the attachment phase of biofilm formation by targeting SrtA.}, } @article {pmid35530774, year = {2019}, author = {Gomes, IB and Simões, LC and Simões, M}, title = {The role of surface copper content on biofilm formation by drinking water bacteria.}, journal = {RSC advances}, volume = {9}, number = {55}, pages = {32184-32196}, pmid = {35530774}, issn = {2046-2069}, abstract = {Copper pipes are conventionally used to supply tap water. Their role in biofilm prevention remains to be understood. This study evaluates the ability of selected surface materials with different copper contents (0, 57, 79, 87, 96, 100% of copper) to control biofilm formation and regrowth. Further experiments were performed to assess copper leaching and corrosion under conditions mimicking real plumbing systems. Acinetobacter calcoaceticus and Stenotrophomonas maltophilia isolated from a drinking water distribution system were used as model bacteria. All the copper materials showed positive results on the control of single and dual species biofilms presenting high reductions of bacterial culturability > 4 log CFU per cm[2]. The antimicrobial action of the selected materials seem not to be related to copper leaching or to the formation of reactive oxygen species. However, bacterial-copper contact demonstrated damage to bacterial membranes. The alloy containing 96% copper was the most promising surface in reducing biofilm culturability and viability, and was the only surface able to avoid the regrowth of single species biofilms when in contact with high nutrient concentrations. The alloy with 87% copper was shown to be unsuitable for use in chlorinated systems due to the high copper leaching observed when exposed to free chlorine. The presence of viable but non-culturable bacteria was remarkable, particularly in dual species biofilms. The overall results provide novel data on the role of copper alloys for use under chlorinated and unchlorinated conditions. Copper alloys demonstrated comparable or even higher biofilm control effects than elemental copper surfaces.}, } @article {pmid35528391, year = {2019}, author = {Bai, JW and Chen, XR and Tang, Y and Cui, WQ and Li, DL and God'spower, BO and Yang, Y}, title = {Study on microwave assisted extraction of chrysophanol and its intervention in biofilm formation of Streptococcus suis.}, journal = {RSC advances}, volume = {9}, number = {50}, pages = {28996-29004}, pmid = {35528391}, issn = {2046-2069}, abstract = {A microwave assisted extraction technology was used to extract chrysophanol from rhubarb. The present study will focus on the optimum extraction conditions of chrysophanol and discuss the inhibitory effect of chrysophanol on the biofilm formation of Streptococcus suis (S. suis). A Box-Behnken design based on single-factor experiments was applied to optimize the microwave assisted extraction process and to study the factors' relationships with each other. The results showed that a microwave temperature of 56 °C, ethanol concentration of 70%, microwave power of 540 W and liquid to raw material ratio of 55 mL g[-1] were the optimal conditions for the microwave method. The yield of chrysophanol was 2.54 ± 0.07% under the optimal conditions, which was in agreement with the predicted value (2.64%). Then, the chemical structure of the extracted chrysophanol was identified by LC-MS. In addition, in vitro experiments showed that chrysophanol has an inhibitory effect on S. suis (minimum inhibitory concentration was 1.98 μg mL[-1]) and was shown to significantly inhibit the capability of S. suis to form a biofilm using crystal violet staining. Finally, scanning electron microscopy analysis showed that the three-dimensional structure of the biofilm deposited by the S. suis community was destroyed by chrysophanol.}, } @article {pmid35529628, year = {2019}, author = {Sharma, S and Gopu, V and Sivasankar, C and Shetty, PH}, title = {Hydrocinnamic acid produced by Enterobacter xiangfangensis impairs AHL-based quorum sensing and biofilm formation in Pseudomonas aeruginosa.}, journal = {RSC advances}, volume = {9}, number = {49}, pages = {28678-28687}, pmid = {35529628}, issn = {2046-2069}, abstract = {Many of the Gram-negative bacteria regulate their virulence through an AHL-mediated quorum sensing (QS) mechanism. Disruption of this signaling mechanism might be a novel strategy to suppress bacterial virulence. In this report, foodborne bacterial isolates were tested for their QS-inhibitory properties using biosensor strain Chromobacterium violaceum CV026 and the extracted potential active components were evaluated for anti-QS and antibiofilm activity against pathogenic bacteria. The cell-free supernatant of Enterobacter xiangfangensis PUFSTI26 inhibited violacein production in the reporter strain and exhibited a significant reduction in extracellular virulence factors like biofilm formation, pyocyanin production, and motility of Pseudomonas aeruginosa. Characterization of the purified active component by gas chromatography-mass spectrometry (GC-MS) flaunted the resemblance of hydrocinnamic acid (HCA). Treatment of HCA exhibited pronounced attenuation of virulence factors. Further, the biofilm inhibitory activity was evidenced by means of confocal laser microscopy, that evidenced the repression of biofilm biomass. In addition, gene quantification analysis revealed that HCA repressed the expression of major QS-regulated genes. In silico studies showed that HCA competitively interacts with LasR receptor protein. These results clearly indicate the anti-virulence properties of HCA extracted from E. xiangfangensis of food origin. This is also the first report of the QS inhibitor activity of HCA.}, } @article {pmid35528677, year = {2019}, author = {Liu, Z and Xiang, P and Duan, Z and Fu, Z and Zhang, L and Zhang, Z}, title = {Electricity generation, salinity, COD removal and anodic biofilm microbial community vary with different anode CODs in a microbial desalination cell for high-salinity mustard tuber wastewater treatment.}, journal = {RSC advances}, volume = {9}, number = {43}, pages = {25189-25198}, pmid = {35528677}, issn = {2046-2069}, abstract = {A three-chamber microbial desalination cell (MDC) was constructed for high-salinity mustard tuber wastewater (MTWW) treatment. The effect of anode COD on electricity generation, salinity, COD removal and the anodic biofilm microbial community in MDC for the MTWW treatment was investigated. The results showed that electricity generation was better when the anode COD was 900 mg L[-1] versus when it was 400 or 1400 mg L[-1]. The ionic strength and conductivity of the anolyte were higher than those at 400 mg L[-1]; thus, the ohmic internal resistance was lower. In addition, the mass transfer internal resistance was lower than that at 1400 mg L[-1], which made the system internal resistance the lowest; consequently, the voltage and power density were the highest. The output voltage, power density and coulombic efficiency of the 1000 Ω external resistors were 555 mV, 3.03 W m[-3] and 26.5% ± 0.4%, respectively. Desalination was the highest when the anode COD was 400 mg L[-1]. The lowest ionic strength and osmotic pressure of the anolyte resulted in the strongest osmosis, thereby producing the highest desalination rate; the desalination rate was 5.33 mg h[-1]. When MDC was coupled with the dual-chamber microbial fuel cell (MFC), the desalinated MTWW could be used as the anode substrate of the MFC; its high COD could be removed continuously, and the COD removal values were 86.2% ± 2.5%, 83.0% ± 2.0% and 84.3% ± 2.4%. High-throughput sequencing analysis indicated that hydrolytic and fermentative bacteria were the core anode bacteria of MDC. The abundances of electrochemically active bacteria in the anode biofilms of the three groups were 11.78% (400 mg L[-1] COD), 14.06% (900 mg L[-1] COD) and 13.68% (1400 mg L[-1] COD). Therefore, the differences in anode CODs impacted the abundance of electrochemically active bacteria, which led to differences in electricity generation performances.}, } @article {pmid35030792, year = {2019}, author = {Fenati, RA and Locock, K and Qu, Y and Ellis, AV}, title = {Oxacillin Coupled G-Quadruplexes as a Novel Biofilm-Specific Antibiotic for Staphylococcus aureus Biofilms.}, journal = {ACS applied bio materials}, volume = {2}, number = {7}, pages = {3002-3008}, doi = {10.1021/acsabm.9b00336}, pmid = {35030792}, issn = {2576-6422}, abstract = {One of the most important traits of pathogenic microbial biofilms is their high tolerance to conventional antimicrobial agents, which is partially due to the presence of metabolically inactive and transiently resistant persister cells. Here, we use guanine-rich DNA structures known as G-quadruplexes (G4s) coupled with the β-lactam antibiotic, oxacillin (OX), and loaded with an iron-containing protoporphyrin IX (hemin), as OXG4/hemin complex biofilm-specific antibiotic agents. By coupling the OX to the G4, to form an OXG4/hemin complex, the diffusion of the OX was facilitated into the biofilm. Further, by utilizing the known oxidizing behavior (peroxidase-mimicking) of the G4/hemin complex, the entire system was found to be highly effectively against Staphylococcus aureus biofilms. By using G4 structures to penetrate biofilms, this work paves the way for an entirely new DNA-based therapy for biofilm eradication.}, } @article {pmid35030785, year = {2019}, author = {Chen, L and Yang, Y and Zhang, P and Wang, S and Xu, JF and Zhang, X}, title = {Degradable Supramolecular Photodynamic Polymer Materials for Biofilm Elimination.}, journal = {ACS applied bio materials}, volume = {2}, number = {7}, pages = {2920-2926}, doi = {10.1021/acsabm.9b00284}, pmid = {35030785}, issn = {2576-6422}, abstract = {In this work, we fabricated a degradable supramolecular photodynamic polymer (SPP) with an enhanced efficiency of biofilm elimination. The small-molecule photosensitizer, a cationic porphyrin derivative, was grafted to a block polymer backbone (BPB) through a host-guest interaction and metal coordination. The locally enriched cationic photosensitizer in SPP endows a high efficiency to disrupt biofilms due to the generated reactive oxygen species (ROS) around the bacteria under white light illumination, while reducing the cytotoxicity to mammalian cells. After cucurbit[7]uril was added as a competitive agent, the photosensitizer could be disassociated from the BPB and the antibacterial ability was reduced; also the SPP could be further degraded. As a consequence, the supramolecular photodynamic polymer may become a very promising material for biofilm elimination with an enhanced antibacterial efficacy and degradability to fight against drug-resistant bacteria.}, } @article {pmid35619519, year = {2019}, author = {Cao, J and Zhao, Y and Liu, Y and Tian, S and Zheng, C and Liu, C and Zhai, Y and An, Y and Busscher, HJ and Shi, L and Liu, Y}, title = {Phosphorylcholine-Based Polymer Encapsulated Chitosan Nanoparticles Enhance the Penetration of Antimicrobials in a Staphylococcal Biofilm.}, journal = {ACS macro letters}, volume = {8}, number = {6}, pages = {651-657}, doi = {10.1021/acsmacrolett.9b00142}, pmid = {35619519}, issn = {2161-1653}, abstract = {Biofilms that contribute to the persistent bacterial infections pose serious threats to human health, due in part to the extracellular polymeric substances (EPS) matrix of biofilm block the diffusion of intact antimicrobials. The poor penetration of antimicrobials into biofilm greatly reduces their bacterial killing efficacy. Here, we have demonstrated a nanocapsule PMPC-CS synthesized by encapsulating a chitosan nanoparticle with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). Such PMPC-based surface exhibited low EPS-adsorption, allowing enhanced penetration of PMPC-CS. Additionally, PMPC-CS showed effective targeting toward negatively charged bacterial cell surfaces and pH-responsive drug release mediated by the swelling of chitosan core under the acidic environment of biofilm. These unique features ensured targeted delivery of antimicrobials throughout the depth of a biofilm. Delivery of triclosan with PMPC-CS outperformed direct application of free triclosan in inhibiting the growth of bacteria in biofilm, suggesting the potential of PMPC-CS as an effective delivery system for the treatment of bacterial infections.}, } @article {pmid35519311, year = {2019}, author = {Anjum, A and Chung, PY and Ng, SF}, title = {PLGA/xylitol nanoparticles enhance antibiofilm activity via penetration into biofilm extracellular polymeric substances.}, journal = {RSC advances}, volume = {9}, number = {25}, pages = {14198-14208}, pmid = {35519311}, issn = {2046-2069}, abstract = {Biofilms are gelatinous masses of microorganisms attached to wound surfaces. Previous studies suggest that biofilms generate resistance towards antibiotic treatments. It was reported that hydrogels containing xylitol and antibiotic combinations produced additive antibiofilm inhibition. However, hydrogel formulations lack specificity, due to which xylitol cannot penetrate into the biofilm matrix and gets easily degraded by bacterial beta lactamase enzymes. It was hypothesized that the incorporation of xylitol in PLGA (polylactic-co-glycolic acid) nanoparticles will enhance penetration into the EPS (extra polymeric substance) component of the biofilm matrix and potentially overcome the antibiotic resistance associated with the biofilms. The purpose of this study was to develop PLGA nanoparticles loaded with xylitol, which will enhance bacterial biofilm penetration. The nanoparticles were loaded with different amounts of xylitol (0.5-5% w/w) and characterized for physiochemical and drug release properties. The metabolic antibiofilm activity of the PLGA nanoparticles containing xylitol was demonstrated by an XTT assay using as references the cultures of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) and the polymicrobial biofilms of both bacterial strains. Live/dead viability staining was also performed to investigate the viability ratio of bacterial cells present in the biofilms. The biofilm penetration study of the PLGA nanoparticles was assessed by combining the nanoparticles with conjugated concanavalin A (Con A)-fluorescein isothiocyanate (FITC) and by viewing using confocal laser scanning electron microscopy (CLSM). In conclusion, the PLGA nanoparticles loaded with xylitol were successfully developed and were found to promote the antibiofilm activity of xylitol in infected wounds.}, } @article {pmid35520264, year = {2019}, author = {Klotz, M and Kretschmer, M and Goetz, A and Ezendam, S and Lieleg, O and Opitz, M}, title = {Importance of the biofilm matrix for the erosion stability of Bacillus subtilis NCIB 3610 biofilms.}, journal = {RSC advances}, volume = {9}, number = {20}, pages = {11521-11529}, pmid = {35520264}, issn = {2046-2069}, abstract = {Production and secretion of biomolecules can provide new emergent functionalities to the synthesizing organism. In particular, the secretion of extracellular polymeric substances (EPS) by biofilm forming bacteria creates a biofilm matrix that protects the individual bacteria within the biofilm from external stressors such as antibiotics, chemicals and shear flow. Although the main matrix components of biofilms formed by Bacillus subtilis are known, it remains unclear how these matrix components contribute to the erosion stability of B. subtilis biofilms. Here, we combine different biophysical techniques to assess this relation. In particular, we quantify the importance of specific biofilm matrix components on the erosion behavior of biofilms formed by the well-studied Bacillus subtilis NCIB 3610. We find that the absence of biofilm matrix components decreases the erosion stability of NCIB 3610 biofilms in water, largely by abolishing the hydrophobic surface properties of the biofilm and by reducing the biofilm stiffness. However, the erosion resistance of NCIB 3610 biofilms is strongly increased in the presence of metal ions or the antibiotic ciprofloxacin. In the first case, unspecific ionic cross-linking of biofilm components or individual bacteria seems to be responsible for the observed effect, and in the second case there seems to be an unspecific interaction between the antibiotic and the biofilm matrix. Taken together, our results emphasize the importance of the biofilm matrix to reduce biofilm erosion and give insights into how the specific biomolecules interact with certain chemicals to fulfill this task.}, } @article {pmid35515281, year = {2019}, author = {Ishchuk, OP and Sterner, O and Strevens, H and Ellervik, U and Manner, S}, title = {The use of polyhydroxylated carboxylic acids and lactones to diminish biofilm formation of the pathogenic yeast Candida albicans.}, journal = {RSC advances}, volume = {9}, number = {19}, pages = {10983-10989}, pmid = {35515281}, issn = {2046-2069}, abstract = {The vaginal microbiome of healthy women is a diverse and dynamic system of various microorganisms. Any sudden change in microbe composition can increase the vaginal pH and thus lead to vaginal infections, conditions that affect a large percentage of women each year. The most common fungal strains involved in infections belong to the yeast species Candida albicans. The main virulence factor of C. albicans is the ability to transform from planktonic yeast-form cells into a filamentous form (hyphae or pseudohyphae), with the subsequent formation of biofilm. The hyphal form, constituted by filamentous cells, has the ability to invade tissue and induce inflammation. Our hypothesis is that certain polyhydroxylated carboxylic acids, that may serve as an alternative carbohydrate source and at the same time lower the pH, function as an indicator of a nutrient-rich environment for C. albicans, which favors planktonic cells over hyphae, and thus diminish the formation of biofilm. We have shown that the biofilm formation in C. albicans and other Candida species can be significantly reduced by the addition of glucono-δ-lactone (GDL).}, } @article {pmid35519961, year = {2019}, author = {Dong, H and Jiang, X and Sun, S and Fang, L and Wang, W and Cui, K and Yao, T and Wang, H and Zhang, Z and Zhang, Y and Zhang, Z and Fu, P}, title = {A cascade of a denitrification bioreactor and an aerobic biofilm reactor for heavy oil refinery wastewater treatment.}, journal = {RSC advances}, volume = {9}, number = {13}, pages = {7495-7504}, pmid = {35519961}, issn = {2046-2069}, abstract = {The performance of an efficient denitrification bioreactor-aerobic biofilm reactor cascade for heavy oil refinery wastewater treatment was investigated. Optimum operation parameters for denitrification were found as follows: (1) hydraulic retention time of 8 h; (2) C/NO3 [-]-N molar ratio of 3.75 with acetate as the carbon source; (3) 20% (v/v) carrier filling ratio in the denitrification bioreactor. Under such optimal conditions, a volumetric removal of 0.82 kg N m[-3] d[-1] was obtained. As an alternative low-cost carbon source to acetate, secondary DAF effluent (COD/NO3 [-]-N mass ratio of 5.4) was also detected and a stable activity of denitrification was achieved with adding 25% volume fraction of secondary DAF effluent. Effluent COD of the subsequent aerobic biofilm reactor further decreased satisfying the requirements of the current discharge standards. High-throughput sequencing results exhibited that Rhodocyclaceae and Comamonadaceae were the dominant denitrifiers in the denitrification reactor and Pseudomonas was the dominant microbe in the aerobic biofilm reactor.}, } @article {pmid35518066, year = {2019}, author = {Bai, JR and Wu, YP and Elena, G and Zhong, K and Gao, H}, title = {Insight into the effect of quinic acid on biofilm formed by Staphylococcus aureus.}, journal = {RSC advances}, volume = {9}, number = {7}, pages = {3938-3945}, pmid = {35518066}, issn = {2046-2069}, abstract = {The biofilm formation of Staphylococcus aureus on food contact surfaces is the main risk of food contamination. In the present study, we firstly investigated the inhibitory effect of quinic acid (QA) on biofilm formed by S. aureus. Crystal violet staining assay and microscopy analysis clearly showed that QA at sub-MIC concentrations was able to significantly reduce the biofilm biomass and cause a collapse on biofilm architecture. Meanwhile, fibrinogen binding assay showed that QA had obviously effect on the S. aureus bacteria adhesion. XTT reduction assay and confocal laser scanning microscopic images revealed that QA significantly decreased metabolic activity and viability of biofilm cells. In addition, qRT-PCR analysis explored the potential inhibitory mechanism of QA against biofilm formation, which indicated that QA significantly repressed the gene sarA and activated the gene agrA. Moreover, QA exhibited a highly ability to reduce the number of sessile S. aureus cells adhered on the stainless steel. So, it was suggested that QA could be used as a promising antibiofilm agent to control biofilm formation of S. aureus.}, } @article {pmid35619411, year = {2019}, author = {Park, HH and Sun, K and Seong, M and Kang, M and Park, S and Hong, S and Jung, H and Jang, J and Kim, J and Jeong, HE}, title = {Lipid-Hydrogel-Nanostructure Hybrids as Robust Biofilm-Resistant Polymeric Materials.}, journal = {ACS macro letters}, volume = {8}, number = {1}, pages = {64-69}, doi = {10.1021/acsmacrolett.8b00888}, pmid = {35619411}, issn = {2161-1653}, abstract = {Despite extensive efforts toward developing antibiofilm materials, efficient prevention of biofilm formation remains challenging. Approaches based on a single strategy using either bactericidal material, antifouling coatings, or nanopatterning have shown limited performance in the prevention of biofilm formation. This study presents a hybrid strategy based on a lipid-hydrogel-nanotopography hybrid for the development of a highly efficient and durable biofilm-resistant material. The hybrid material consists of nanostructured antifouling, biocompatible polyethylene glycol-based polymer grafted with an antifouling zwitterionic polymer of 2-methacryloyloxyethyl phosphorylcholine. Based on the unique composite nanostructures, the lipid-hydrogel-nanostructure hybrid exhibits superior dual functionalities of antifouling and bactericidal activities against Gram-negative and Gram-positive bacteria, compared with those of surfaces with simple nanostructures or antifouling coatings. Additionally, it preserves the robust antibiofilm activity even when the material is damaged under external mechanical stimuli thanks to the polymeric composite nanostructure.}, } @article {pmid35532521, year = {2018}, author = {Singh, AK and Yadav, S and Sharma, K and Firdaus, Z and Aditi, P and Neogi, K and Bansal, M and Gupta, MK and Shanker, A and Singh, RK and Prakash, P}, title = {Correction: Quantum curcumin mediated inhibition of gingipains and mixed-biofilm of Porphyromonas gingivalis causing chronic periodontitis.}, journal = {RSC advances}, volume = {9}, number = {1}, pages = {91}, doi = {10.1039/c8ra90104j}, pmid = {35532521}, issn = {2046-2069}, abstract = {[This corrects the article DOI: 10.1039/C8RA08435A.].}, } @article {pmid35558401, year = {2018}, author = {Yin, W and Wang, K and Xu, J and Wu, D and Zhao, C}, title = {The performance and associated mechanisms of carbon transformation (PHAs, polyhydroxyalkanoates) and nitrogen removal for landfill leachate treatment in a sequencing batch biofilm reactor (SBBR).}, journal = {RSC advances}, volume = {8}, number = {74}, pages = {42329-42336}, pmid = {35558401}, issn = {2046-2069}, abstract = {A modified sequencing batch biofilm reactor (SBBR, adding a pre-anoxic phase before the aeration phase) was used to treat landfill leachate. The overall SBBR operation period was divided into a load-increasing period I (69 days) and a steady operation period II (41 days). In period I, the influent total nitrogen (TN) and chemical oxygen demand (COD) concentrations increased from approximately 60 and 400 mg L[-1] to 1000 and 6500 mg L[-1], respectively, and these were kept for period II. In period II, the COD and TN removal rates were 83-88% and 95-98%, with effluent COD and TN concentrations of less than 500-600 and 10-20 mg L[-1], respectively. The end of pre-anoxic phase PHA (polyhydroxyalkanoate) content increased from 0.11 Cmol (start of period I) to 0.22 Cmol (end of period II). The contributions from simultaneous nitrification and denitrification (SND) and endogenous denitrification to the TN removal rate were approximately 60% and 40%, respectively. The mechanisms of carbon transformation and nitrogen removal were: (1) the synthesis of PHAs in the pre-anoxic phase; (2) short-range nitrification; (3) simultaneous nitrification and denitrification (SND); and (4) endogenous denitrification. Microbial diversity analysis revealed that Proteobacteria and Bacteroidetes accounted for 89.66% of the total bacteria. Ammonia-oxidizing bacteria (AOB, Nitrosomonas) and denitrifying bacteria with the ability to transform organic matter into PHAs (Paracoccus and Thauera) are the dominant bacterial communities.}, } @article {pmid35558224, year = {2018}, author = {Singh, AK and Yadav, S and Sharma, K and Firdaus, Z and Aditi, P and Neogi, K and Bansal, M and Gupta, MK and Shanker, A and Singh, RK and Prakash, P}, title = {Quantum curcumin mediated inhibition of gingipains and mixed-biofilm of Porphyromonas gingivalis causing chronic periodontitis.}, journal = {RSC advances}, volume = {8}, number = {70}, pages = {40426-40445}, pmid = {35558224}, issn = {2046-2069}, abstract = {Periodontitis is a biofilm-associated irreversible inflammation of the periodontal tissues. Reports suggest the role of Porphyromonas gingivalis specific Arg- and Lys-specific proteinases in the orchestration of the initiation and progression of periodontal diseases. These proteinases are precisely termed as gingipains R and K. Curcumin is an active polyphenol that is extracted from the rhizomes of Curcuma longa. However, the molecule curcumin owing to its high hydropathy index and poor stability has not been able to justify its role as frontline drug modality in the treatment of infectious and non-infectious diseases as claimed by several investigators. In the present study, at first, we synthesized and characterized quantum curcumin, and investigated its biocompatibility. This was subsequently followed by the evaluation of the role of quantum curcumin as an antimicrobial, anti-gingipains and antibiofilm agent against Porphyromonas gingivalis and select reference strains. We have successfully synthesized the quantum curcumin utilizing a top-down approach with the average size of 3.5 nm. Apart from its potent antimicrobial as well as antibiofilm properties, it also significantly inhibited the gingipains in a dose-dependent manner. At the minimal concentration of 17.826 μM, inhibition up to 98.7% and 89.4% was noted for gingipain R and K respectively. The data was also supported by the in silico docking experiments which revealed high exothermic enthalpies (-7.01 and -7.02 cal mol[-1]). Besides, the inhibition constant was found to be 7.24 μM and 7.1 μM against gingipains R and K respectively. The results suggest that quantum curcumin is a potential drug candidate which needs further clinical validation.}, } @article {pmid35558609, year = {2018}, author = {Chauhan, D and Agrawal, G and Deshmukh, S and Roy, SS and Priyadarshini, R}, title = {Biofilm formation by Exiguobacterium sp. DR11 and DR14 alter polystyrene surface properties and initiate biodegradation.}, journal = {RSC advances}, volume = {8}, number = {66}, pages = {37590-37599}, pmid = {35558609}, issn = {2046-2069}, abstract = {Polystyrene is a chemically inert synthetic aromatic polymer. This widely used form of plastic is recalcitrant to biodegradation. The exponential production and consumption of polystyrene in various sectors has presented a great environment risk and raised the problem of waste management. Biodegradation by bacteria has previously shown great potential against various xenobiotics but there are only a few reports concerning polyolefins. By screening wetland microbes, we found two bacterial species - Exiguobacterium sibiricum strain DR11 and Exiguobacterium undae strain DR14 which showed promising biodegradation potential against polystyrene. In this study, we report the degradation of non-irradiated solid polystyrene material after incubation with these isolates. Growth studies suggested that the Exiguobacterium strains utilize polystyrene as a carbon source. Moreover, our data suggest that polymer degradation was initiated by biofilm formation over the PS surface leading to alteration in the physical properties of the material. Surface property analysis by AFM revealed significantly enhanced roughness resulting in reduced surface hydrophobicity of polystyrene. Fourier-transfer infrared (FT-IR) spectroscopic analysis showed breakdown of polystyrene backbone by oxidation. The extent of deterioration was further determined by percent weight reduction of polystyrene after incubation with bacteria. Our data support the fact that strains of extremophile bacterium Exiguobacterium are capable of degrading polystyrene and can be further used to mitigate the environmental pollution caused by plastics.}, } @article {pmid35557833, year = {2018}, author = {Zhang, R and Wang, L and Chen, P and Pu, Y}, title = {Shifts in microbial community structure and diversity in a novel waterfall biofilm reactor combined with MBBR under light and dark conditions.}, journal = {RSC advances}, volume = {8}, number = {65}, pages = {37462-37471}, pmid = {35557833}, issn = {2046-2069}, abstract = {In this study, a novel, low-cost, easy-maintenance and effective waterfall aeration biofilm reactor (WFBR) was designed to treat wastewater with MBBR. The chemical oxygen demand (COD), nitrogen removal efficiency, and the microbial community structure in this novel system were evaluated for 70 days under light and dark conditions. The COD and ammonium nitrogen (NH3-N) removal efficiency remained at approximately 90% and 100% respectively after 25 days, even if the influent substrate concentration and illumination condition changes. High-throughput sequencing was used to investigate the composition and function of the microbial community in different fillers in the treatment system. Dark padding, illuminate carrier and fabric play the good performance in nitrogen nitrification, denitrification and fixation respectively. The major classes present were Betaproteobacteria (30.2% on average), Cytophagia (19.8%), Gammaproteobacteria (11.7%), Alphaproteobacteria (11.2%), Sphingobacteriia (5.1%), Flavobacteriia (2.6%), Deltaproteobacteria (2.4%), Verrucomicrobiae (0.7%), Chloroplast (0.6%) and Clostridia (0.5%). These results could provide important guidance for the improvement of MBBR or other tradition wastewater treatment process, and could also enrich our theoretical understanding of microbial ecology.}, } @article {pmid35558480, year = {2018}, author = {Aswathanarayan, JB and Vittal, RR}, title = {Inhibition of biofilm formation and quorum sensing mediated phenotypes by berberine in Pseudomonas aeruginosa and Salmonella typhimurium.}, journal = {RSC advances}, volume = {8}, number = {63}, pages = {36133-36141}, pmid = {35558480}, issn = {2046-2069}, abstract = {Quorum sensing is involved in biofilm formation and modulates virulence factor production in pathogenic bacteria. Quorum sensing inhibitors can be used as novel intervention strategies for attenuating bacterial pathogenicity. Berberine is an isoquinoline alkaloid with pharmacological properties. The present study investigated the sub-inhibitory concentrations of berberine for inhibiting biofilm formation and quorum sensing regulated phenotypes in the bacterial pathogens Pseudomonas aeruginosa PA01 and Salmonella enterica serovar Typhimurium. Berberine inhibited quorum sensing regulated violacein production in C. violaceum. It reduced the pigment production in the wild type strain at 1.6 mg mL[-1] by 62.67%. In the opportunistic pathogen, P. aeruginosa PA01, at sub-MIC, it showed significant antibiofilm activity in by reducing biomass by 71.70% (p < 0.05). It prevented biofilm formation and inactivated biofilm maturation in bacterial pathogens at the concentration ranging from 0.019 to 1.25 mg mL[-1]. In silico studies showed that berberine interacted with the quorum sensing signal receptors, LasR and RhlR. Furthermore, its anti-infective properties in S. Typhimurium were studied. At sub-inhibitory concentrations of 0.019 mg mL[-1], it reduced biofilm formation in S. Typhimurium by 31.20%. It significantly prevented invasion and adhesion of Salmonella invasion in the colonic cell, HT 29 by 55.37% and 54.68%, respectively. It was capable of reducing in vivo virulence in Caenorhabditis elegans infected with Salmonella at 0.038 mg mL[-1] by 65.38%. Our results suggest that berberine, previously recognised for its antimicrobial activity, could find potential application as an anti-biofilm and anti-infective agent based on its quorum sensing inhibitory activity.}, } @article {pmid35547056, year = {2018}, author = {Yu, L and Tran, DNH and Forward, P and Lambert, MF and Losic, D}, title = {The hydrothermal processing of iron oxides from bacterial biofilm waste as new nanomaterials for broad applications.}, journal = {RSC advances}, volume = {8}, number = {61}, pages = {34848-34852}, pmid = {35547056}, issn = {2046-2069}, abstract = {Iron oxides and their hydroxides have been studied and analysed with properties of their mutual transformations under different hydrothermal conditions being indicated. Amorphous bacteria nanowires produced from biofilm waste were investigated under the influence of pH at a fixed duration (20 h) and reaction temperature (200 °C). The morphology, structure, and particle size of the transformation of hematite (α-Fe2O3) was obtained and characterised with SEM, XRD, FTIR, and particle sizer. The optimal conditions for the complete conversion of amorphous iron oxide nanowires to crystalline α-Fe2O3 is under acidic conditions where the pH is 1. The flower-like α-Fe2O3 structures have photocatalytic activity and adsorbent properties for heavy metal ions. This one-pot synthesis approach to produce α-Fe2O3 at a low cost would be greatly applicable to the recycling process of biofilm waste in order to benefit the environment.}, } @article {pmid35547717, year = {2018}, author = {Bordeleau, E and Mazinani, SA and Nguyen, D and Betancourt, F and Yan, H}, title = {Abrasive treatment of microtiter plates improves the reproducibility of bacterial biofilm assays.}, journal = {RSC advances}, volume = {8}, number = {57}, pages = {32434-32439}, pmid = {35547717}, issn = {2046-2069}, abstract = {Microtiter plate-based bacterial biofilm assay is frequently used to study bacterial biofilm development and growth. While this assay is simple and relatively high-throughput, it frequently shows difficulty in establishing robust biofilm attachment in the wells. We report that the consistency of bacterial biofilm assays carried out in microtiter plates subjected to abrasive treatment, by sandblasting or drill press grinding, is significantly improved in a Pseudomonas fluorescens Pf0-1 model. Scanning electron microscopy imaging suggests that the treated surfaces could provide points of attachment to facilitate the recruitment of bacteria in the initial phase of biofilm colony establishment. The sandblast treated polypropylene, but not polystyrene, plates were found suitable in studying the impact of flavonoid quercetin on the biofilm formation in Bacillus subtilis FB17. Further investigation revealed that due to the hydrophobicity of the polystyrene surfaces, a greater amount of quercetin was adsorbed on the plate surface, effectively lowering the concentration of the flavonoid in solution.}, } @article {pmid35548734, year = {2018}, author = {Wang, X and Wang, W and Li, Y and Zhang, J and Zhang, Y and Li, J}, title = {Biofilm activity, ammonia removal and cell growth of the heterotrophic nitrifier, Acinetobacter sp., facilitated by exogenous N-acyl-homoserine lactones.}, journal = {RSC advances}, volume = {8}, number = {54}, pages = {30783-30793}, pmid = {35548734}, issn = {2046-2069}, abstract = {In the present study, the heterotrophic nitrification-aerobic denitrification strain, Acinetobacter sp. JQ1004, was treated with three typical N-acyl-homoserine lactone (AHL) molecules (C6-HSL, C8-HSL, and 3-oxo-C10-HSL) during the nitrogen removal process. The effects of AHLs on biofilm formation, flocculation, extracellular polymeric substance characteristics, and nitrogen removal were investigated. Findings revealed that low concentrations of these three AHLs could promote ammonia removal and cell growth as follows: C8-HSL > C6-HSL > 3-oxo-C10-HSL, whereas high concentrations suppressed nitrogen removal. Transcript levels of the amoA gene in the heterotrophic nitrification process were detected by real-time PCR, indicating that the addition of each AHL with 10 nmol L[-1] could stimulate expression of amoA. Notably, the addition of C6-HSL at relative lowly concentrations significantly accelerated biofilm formation and self-aggregation of strain JQ1004. Many microbial-flocs were observed between cells using scanning electron microscopy when strains were dosed with 10 nmol L[-1] C6-HSL. Excitation emission matrix spectra revealed that the addition of C6-HSL and C8-HSL at 10 nmol L[-1] did not change the components and structures of the extracellular polymeric substance (EPS), but the fluorescence intensity of various components increased substantially. However, the addition of 3-oxo-C10-HSL reduced the fluorescence strength of EPS, which had no remarkable effect on biofilm formation, self-aggregation, and nitrogen removal of the strain.}, } @article {pmid35632937, year = {2018}, author = {Namivandi-Zangeneh, R and Sadrearhami, Z and Bagheri, A and Sauvage-Nguyen, M and Ho, KKK and Kumar, N and Wong, EHH and Boyer, C}, title = {Nitric Oxide-Loaded Antimicrobial Polymer for the Synergistic Eradication of Bacterial Biofilm.}, journal = {ACS macro letters}, volume = {7}, number = {5}, pages = {592-597}, doi = {10.1021/acsmacrolett.8b00190}, pmid = {35632937}, issn = {2161-1653}, abstract = {Bacterial biofilms are often difficult to treat and represent the main cause of chronic and recurrent infections. In this study, we report the synthesis of a novel antimicrobial/antibiofilm polymer that consists of biocompatible oligoethylene glycol, hydrophobic ethylhexyl, cationic primary amine, and nitric oxide (NO)-releasing functional groups. The NO-loaded polymer has dual-action capability as it can release NO which triggers the dispersion of biofilm, whereas the polymer can induce bacteria cell death via membrane wall disruption. By functionalizing the polymers with NO, we observed a synergistic effect in biofilm dispersal, planktonic and biofilm killing activities against Pseudomonas aeruginosa. The NO-loaded polymer results in 80% reduction in biofilm biomass and kills >99.999% of planktonic and biofilm P. aeruginosa cells within 1 h of treatment at a polymer concentration of 64 μg mL[-1]. To achieve this synergistic effect, it is imperative that the NO donors and antimicrobial polymer exist as a single chemical entity, instead of a cocktail physical mixture of two individual components. The excellent antimicrobial/antibiofilm activity of this dual-action polymer suggests the advantages of combination therapy in combating bacterial biofilms.}, } @article {pmid35542191, year = {2018}, author = {Feng, XC and Guo, WQ and Zheng, HS and Wu, QL and Luo, HC and Ren, NQ}, title = {Effect of metabolic uncoupler, 3,3',4',5-tetrachlorosalicylanilide (TCS) on Bacillus subtilis: biofilm formation, flocculability and surface characteristics.}, journal = {RSC advances}, volume = {8}, number = {29}, pages = {16178-16186}, pmid = {35542191}, issn = {2046-2069}, abstract = {In order to understand the inhibitory mechanism of metabolic uncoupler in biofilm, this study investigated the effect of TCS on B. subtilis biofilm formation, flocculability, surface characteristics and thermodynamic properties. An optimal concentration of TCS, a metabolic uncoupler, was observed to substantially inhibit biofilm formation and the secretion of extracellular polymeric substances (EPS). The effect of TCS on the zeta potential and flocculability of bacterial suspension implied the addition of 100 μg L[-1] TCS increased the net negative charge of cell surface which induced the reduction of B. subtilis flocculability. Meanwhile, the effects of TCS on bacterial surfacial thermodynamic properties were analyzed by the Derjaguin-Landau-Verwey-Overbeek (DLVO) and extend DLVO (XDLVO) theories. As DLVO and XDLVO predicted, the primary energy barrier between bacterial cells incubated with 100 μg L[-1] TCS were increased compared to that of control, indicating that B. subtilis incubated with 100 μg L[-1] TCS must consume more energy to aggregate or form biofilm.}, } @article {pmid35542417, year = {2018}, author = {Rakesh, KP and Vivek, HK and Manukumar, HM and Shantharam, CS and Bukhari, SNA and Qin, HL and Sridhara, MB}, title = {Promising bactericidal approach of dihydrazone analogues against bio-film forming Gram-negative bacteria and molecular mechanistic studies.}, journal = {RSC advances}, volume = {8}, number = {10}, pages = {5473-5483}, pmid = {35542417}, issn = {2046-2069}, abstract = {Gram-negative members of the ESCAPE family are more difficult to treat, due to the presence of an additional barrier in the form of a lipopolysaccharide layer and the efficiency of efflux pumps to pump out the drugs from the cytoplasm. The development of alternative therapeutic strategies to tackle ESCAPE Gram-negative members is of extreme necessity to provide a solution to the cause of life-threatening infections. The present investigations demonstrated that compounds 17, 20, 25 and 26 possessing the presence of electron donating (OH and OCH3) groups on the phenyl rings are highly potent; whereas compounds 9, 10, 15, 16, 18, 33 and 36 showed moderate activity against Gram-negative bacteria. An excellent dose-dependent antibacterial activity was established compared to that of the standard antibiotic ampicillin. Significant anti-biofilm properties were measured quantitatively, showing optical density (O.D) values of 0.51 ± 015, 0.63 ± 0.20, 0.38 ± 0.07 and 0.62 ± 0.11 at 492 nm and the leakage of cellular components by the compounds, such as 17, 20, 25 and 26, increased the O.D. of respective treated samples compared to the control. In addition, the implication of experimental results is discussed in the light of the lack of survivability of planktonic bacteria and biofilm destruction in vitro. These results revealed the great significance of the development of a new generation of synthetic materials with greater efficacy in anti-biofilm properties by targeting to lock the bio-film associated protein Bap in Gram-negative bacteria.}, } @article {pmid34853678, year = {2021}, author = {Millones Gómez, PA and Tay Chu Jon, LY and Maurtua Torres, DJ and Bacilio Amaranto, RE and Collantes Díaz, IE and Minchón Medina, CA and Calla Choque, JS}, title = {Antibacterial, antibiofilm, and cytotoxic activities and chemical compositions of Peruvian propolis in an in vitro oral biofilm.}, journal = {F1000Research}, volume = {10}, number = {}, pages = {1093}, pmid = {34853678}, issn = {2046-1402}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Ecosystem ; Humans ; Peru ; *Propolis ; }, abstract = {Background: Natural products with antibacterial potential have begun to be tested on biofilm models, bringing us closer to understanding the response generated by the complex microbial ecosystems of the oral cavity. The objective of this study was to evaluate the antibacterial, antibiofilm, and cytotoxic activities and chemical compositions of Peruvian propolis in an in vitro biofilm of Streptococcus gordonii and Fusobacterium nucleatum. Methods: The experimental work involved a consecutive, in vitro, longitudinal, and double-blinded study design. Propolis samples were collected from 13 different regions of the Peruvian Andes. The disk diffusion method was used for the antimicrobial susceptibility test. The cytotoxic effect of propolis on human gingival fibroblasts was determined by cell viability method using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay, and the effect of propolis on the biofilm was evaluated by confocal microscopy and polymerase chain reaction (PCR). Results: The 0.78 mg/mL and 1.563 mg/mL concentrations of the methanolic fraction of the chloroform residue of Oxapampa propolis showed effects on biofilm thickness and the copy numbers of the srtA gene of S. gordonii and the radD gene of F. nucleatum at 48 and 120 hours, and chromatography (UV, λ 280 nm) identified rhamnocitrin, isorhamnetin, apigenin, kaempferol, diosmetin, acacetin, glycerol, and chrysoeriol. Conclusions: Of the 13 propolis evaluated, it was found that only the methanolic fraction of Oxapampa propolis showed antibacterial and antibiofilm effects without causing damage to human gingival fibroblasts. Likewise, when evaluating the chemical composition of this fraction, eight flavonoids were identified.}, } @article {pmid35028071, year = {2022}, author = {Zou, P and Cao, P and Liu, J and Li, P and Luan, Q}, title = {Comparisons of the killing effect of direct current partially mediated by reactive oxygen species on Porphyromonas gingivalis and Prevotella intermedia in planktonic state and biofilm state - an in vitro study.}, journal = {Journal of dental sciences}, volume = {17}, number = {1}, pages = {459-467}, pmid = {35028071}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: Bacterial biofilms formed on the surface of tissues and biomaterials are major causes of chronic infections in humans. Among them, Porphyromonas gingivalis (P. gingivalis) and Prevotella intermedia (P. intermedia) are anaerobic pathogens causing dental infections associated with periodontitis. In this study, we evaluated the killing effect and underlying mechanisms of direct current (DC) as an antimicrobial method in vitro.

MATERIALS AND METHODS: We chose P. gingivalis and P. intermedia in different states to make comparisons of the killing effect of DC. By viable bacteria counting, fluorescent live/dead staining, reactive oxygen species (ROS) assay, addition of ROS scavenger DMTU and mRNA expression assay of ROS scavenging genes, the role of ROS in the killing effect was explored.

RESULTS: The planktonic and biofilm states of two bacteria could be effectively killed by low-intensity DC. For the killing effect of 1000 μA DC, there were significant differences whether on planktonic P. gingivalis and P. intermedia (mean killing values: 2.40 vs 2.62 log10 CFU/mL) or on biofilm state of those (mean killing values: 0.63 vs 0.98 log10 CFU/mL). 1000 μA DC greatly induced ROS production and the mRNA expression of ROS scavenging genes. DMTU could partially decrease the killing values of DC and downregulate corresponding gene's expression.

CONCLUSION: 1000 μA DC can kill P. gingivalis and P. intermedia in two states by promoting overproduction of ROS, and P. intermedia is more sensitive to DC than P. gingivalis. These findings indicate low-intensity DC may be a promising approach in treating periodontal infections.}, } @article {pmid35028062, year = {2022}, author = {Komalsingsakul, A and Srisatjaluk, RL and Senawongse, P}, title = {Effect of brushing on surface roughness, fluoride release, and biofilm formation with different tooth-colored materials.}, journal = {Journal of dental sciences}, volume = {17}, number = {1}, pages = {389-398}, pmid = {35028062}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: Tooth brushing, material mechanical ageing procedure, is the most effective way in removing biofilm. The purpose of this study was to investigate the surface roughness, fluoride-release, and S. mutans biofilm formation on various tooth-colored restorative materials before and after brushing.

MATERIALS AND METHODS: Discs of materials, a nanocomposite (Filtek Z350XT; CO), a giomer (Beautifil II; GIOMER), a resin-modified glass-ionomer material (Fuji II LC; RMGI), and a conventional glass-ionomer material (Fuji IX GP Extra; GI), were prepared, polished with abrasive discs (SofLex), and divided into brushed and not brushed groups. The surface roughness of specimens was observed using a contact profilometer, fluoride-release was measured using a fluoride-specific ion electrode, and S. mutans biofilm formation, biovolume and live/dead cells, was observed under a confocal laser scanning microscope.

RESULTS: Higher roughness was observed on GI and RMGI than on CO and GIOMER. Brushing had no effect on the roughness. The fluoride-release of GI and RMGI was higher than that of GIOMER. The fluoride-release decreased after brushing in all materials. The biovolume of S. mutans was not significantly different between GIOMER, RMGI and GI, while CO showed the highest. Brushing resulted in a higher biovolume for all materials, except CO, which showed no change. After brushing, all the tested materials demonstrated identical biovolumes. There were no significant differences in live/dead cells among all groups.

CONCLUSION: Brushing demonstrated a negative effect on the fluoride-release and biovolume of S. mutans biofilms for all tested materials except nanocomposites.}, } @article {pmid35028040, year = {2022}, author = {Holguin-Loya, B and Soto-Barreras, U and Martinez-Martinez, R and Martinez-Mata, G and Sanin, L and Nevarez-Rascon, M and Dominguez-Perez, R}, title = {Relationship between fluoride exposure and count of Streptococcus mutans in supragingival biofilm of mexican scholar children.}, journal = {Journal of dental sciences}, volume = {17}, number = {1}, pages = {211-216}, pmid = {35028040}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: The use of fluoride is known to reduce the risk of dental caries. There is limited information on the relationship between Streptococcus mutans (S. mutans) and fluoride exposure. This study investigated the association between the count of S. mutans on supragingival biofilm and fluoride exposure of scholar children.

MATERIALS AND METHODS: In this cross-sectional study, 56 children from 9 to 11 years of age were selected. Fluoride concentration in drinking water, urine and saliva of each participant were assessed. The count of S. mutans was estimated by calculating the DNA copy number through a quantitative real time polymerase chain reaction (qPCR) assay. Also, sociodemographic data, oral and general health information and variables related to caries risk were evaluated. A stepwise multiple linear regression was performed in all caries related predictor variables with the count of S. mutans as the dependent variable.

RESULTS: The multiple linear regression analysis showed that the concentration of fluoride in saliva (β = -3.029, p < 0.001) and urine (β = -2.057, p = 0.017), time of last visit to the dentist (β = 1.968, p = 0.001), plaque index (β = 1.637, p = 0.006) and number of surfaces with codes 3-6 (D3-6MFS) of ICDAS II criteria (β = 0.283, p = 0.076) were significantly associated with the count of S. mutans (Adjusted R square = 0.427, p < 0.001).

CONCLUSION: Fluoride levels in urine and saliva were negatively associated with the count of S. mutans in supragingival biofilm. Plaque index, D3-6MFS and time of last visit to the dentist showed a positive association.}, } @article {pmid35026999, year = {2022}, author = {Farshadzadeh, Z and Pourhajibagher, M and Taheri, B and Ekrami, A and Modarressi, MH and Azimzadeh, M and Bahador, A}, title = {Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1L against Acinetobacter baumannii: an in vivo wound healing model.}, journal = {BMC microbiology}, volume = {22}, number = {1}, pages = {25}, pmid = {35026999}, issn = {1471-2180}, mesh = {Acinetobacter Infections/complications/*drug therapy ; Acinetobacter baumannii/*drug effects ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Disease Models, Animal ; Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Peptides/*pharmacology ; Wound Healing/*drug effects ; Wound Infection/drug therapy/microbiology ; }, abstract = {BACKGROUND: The global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii.

METHODS: After determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed.

RESULTS: The bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L.

CONCLUSIONS: Results of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.}, } @article {pmid35026447, year = {2022}, author = {Sterniša, M and Sabotič, J and Klančnik, A}, title = {A novel approach using growth curve analysis to distinguish between antimicrobial and anti-biofilm activities against Salmonella.}, journal = {International journal of food microbiology}, volume = {364}, number = {}, pages = {109520}, doi = {10.1016/j.ijfoodmicro.2021.109520}, pmid = {35026447}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; *Foodborne Diseases ; Humans ; Microbial Sensitivity Tests ; Plant Extracts ; Salmonella ; }, abstract = {Salmonella spp. are a commonly identified cause of outbreaks of food-borne diseases. Despite much research, there remains the need to find new antimicrobial and anti-biofilm agents against Salmonella. For this, it is necessary to distinguish between these two aspects. Agents that influence biofilm formation should not affect bacterial growth, to thus avoid further promotion of the development of resistance. In this study, we present the use of growth curves of Salmonella Infantis to simultaneously determine antimicrobial and anti-biofilm activities, for the screening for anti-Salmonella activities of 42 aqueous fungal extracts. The extract from Pseudohydnum gelatinosum showed good antimicrobial activity, and that from Pleurotus ostreatus showed good anti-biofilm activity. In extracts from Infundibulicybe geotropa and Infundibulicybe gibba, both activities were determined after fractionation. The antimicrobial activity was associated with protein-rich fractions and mediated by l-amino acid oxidase activity. The fractionation did not allow determination of the anti-biofilm active fraction, so further studies are needed to define these compounds. Growth curve analysis of S. Infantis is shown here to provide a fast and simple approach to distinguish between antimicrobial and anti-biofilm activities in a high-throughput setting, such that it can be easily implemented in screening and further bioassay-based purification of novel alternatives to antibiotics.}, } @article {pmid35025506, year = {2022}, author = {Bhowmik, P and Rajagopal, S and Hmar, RV and Singh, P and Saxena, P and Amar, P and Thomas, T and Ravishankar, R and Nagaraj, S and Katagihallimath, N and Sarangapani, RK and Ramachandran, V and Datta, S}, title = {Validated In Silico Model for Biofilm Formation in Escherichia coli.}, journal = {ACS synthetic biology}, volume = {11}, number = {2}, pages = {713-731}, doi = {10.1021/acssynbio.1c00445}, pmid = {35025506}, issn = {2161-5063}, mesh = {Bacteria ; Biofilms ; Computer Simulation ; *Escherichia coli/genetics ; *Escherichia coli Infections/microbiology ; Humans ; }, abstract = {Using Escherichia coli as the representative biofilm former, we report here the development of an in silico model built by simulating events that transform a free-living bacterial entity into self-encased multicellular biofilms. Published literature on ∼300 genes associated with pathways involved in biofilm formation was curated, static maps were created, and suitably interconnected with their respective metabolites using ordinary differential equations. Precise interplay of genetic networks that regulate the transitory switching of bacterial growth pattern in response to environmental changes and the resultant multicomponent synthesis of the extracellular matrix were appropriately represented. Subsequently, the in silico model was analyzed by simulating time-dependent changes in the concentration of components by using the R and python environment. The model was validated by simulating and verifying the impact of key gene knockouts (KOs) and systematic knockdowns on biofilm formation, thus ensuring the outcomes were comparable with the reported literature. Similarly, specific gene KOs in laboratory and pathogenic E. coli were constructed and assessed. MiaA, YdeO, and YgiV were found to be crucial in biofilm development. Furthermore, qRT-PCR confirmed the elevation of expression in biofilm-forming clinical isolates. Findings reported in this study offer opportunities for identifying biofilm inhibitors with applications in multiple industries. The application of this model can be extended to the health care sector specifically to develop novel adjunct therapies that prevent biofilms in medical implants and reduce emergence of biofilm-associated resistant polymicrobial-chronic infections. The in silico framework reported here is open source and accessible for further enhancements.}, } @article {pmid35024736, year = {2021}, author = {Bugari, RA and Başchir, AS and Turcin, LA and Chioreanu, A and Mihali, CV and Ilie, AC and Jompan, A and Bălăşoiu, M}, title = {Adenoidal bacterial biofilm in pediatric rhinosinusitis.}, journal = {Romanian journal of morphology and embryology = Revue roumaine de morphologie et embryologie}, volume = {62}, number = {2}, pages = {481-489}, pmid = {35024736}, issn = {2066-8279}, mesh = {Adenoidectomy ; *Adenoids ; Biofilms ; Child ; Humans ; *Sinusitis ; *Sleep Apnea, Obstructive ; }, abstract = {The aim of the study was to observe, using scanning electron microscopy (SEM), the ratio of bacterial biofilm coverage of adenoidal tissue in children diagnosed with chronic rhinosinusitis (CR), compared to the ratio of adenoid bacterial biofilm coverage in children diagnosed with obstructive sleep apnea (OSA). We also performed histopathological and immunohistochemical tests to correlate the results with the images obtained from SEM. We estimated, using an image analysis program, the coverage ratio with bacterial biofilm on the surface of the lymphatic tissue. Adenoid vegetation extracted from children with CR had a higher percentage of bacterial biofilm coverage compared to the group diagnosed with OSA. In the nasopharynx of children with CR, the bacterial biofilm had a constant role of infection generator, and adenoidectomy was the only effective therapeutic procedure to relieve the symptoms. Allergy tests were performed in all children to establish a link between CR, OSA and allergic rhinitis.}, } @article {pmid35024609, year = {2022}, author = {Sanchez-Vizuete, P and Dergham, Y and Bridier, A and Deschamps, J and Dervyn, E and Hamze, K and Aymerich, S and Le Coq, D and Briandet, R}, title = {The coordinated population redistribution between Bacillus subtilis submerged biofilm and liquid-air pellicle.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100065}, pmid = {35024609}, issn = {2590-2075}, abstract = {Bacillus subtilis is a widely used bacterial model to decipher biofilm formation, genetic determinants and their regulation. For several years, studies were conducted on colonies or pellicles formed at the interface with air, but more recent works showed that non-domesticated strains were able to form thick and structured biofilms on submerged surfaces. Taking advantage of time-lapse confocal laser scanning microscopy, we monitored bacterial colonization on the surface and observed an unexpected biphasic submerged biofilm development. Cells adhering to the surface firstly form elongated chains before being suddenly fragmented and released as free motile cells in the medium. This switching coincided with an oxygen depletion in the well which preceded the formation of the pellicle at the liquid-air interface. Residual bacteria still associated with the solid surface at the bottom of the well started to express matrix genes under anaerobic metabolism to build the typical biofilm protruding structures.}, } @article {pmid35024198, year = {2022}, author = {Palencia, SL and García, A and Palencia, M}, title = {Multiple surface interaction mechanisms direct the anchoring, co-aggregation and formation of dual-species biofilm between Candida albicans and Helicobacter pylori.}, journal = {Journal of advanced research}, volume = {35}, number = {}, pages = {169-185}, pmid = {35024198}, issn = {2090-1224}, mesh = {Biofilms ; *Candida albicans ; *Helicobacter pylori/genetics ; Humans ; }, abstract = {INTRODUCTION: Polymicrobial biofilms have a significant impact on pathogenesis of infectious microorganisms. Many human diseases are affected by colonization of multi-species communities affecting negatively the treatments and increase the risks for the health. In particular, in the epithelium of the stomach co-existence between C. albicans and H. pylori has been described, which has been associated to a synergistic effect on ulcer pathogenesis.

OBJECTIVE: The objective of this work was to advance in the understanding of surface interaction between H. pylori and C. albicans for the formation of polymicrobial biofilms.

METHODS: Studies of microbial surfaces both bacterium, yeast and co-cultures of them were carried out by infrared spectroscopy, deconvolution analysis, transmission and scanning electron microscopies, and optic microscopy. Additional methods were used to contrast the results as dynamic light scattering, contact angle, agarose gel electrophoresis and gene amplification.

RESULTS: Several surface interaction mechanisms promote the anchoring of H. pylori on C. albicans, cell co-aggregation, and polymicrobial biofilm formation, main identified interactions were: (i) hydrophobic interactions between non-polar peptide chains and lipid structures, characterized by θw among 84.9 ± 1.6 (γ = 22.78 mJ/m[2] with 95.3 of dispersive contribution) and 76.6 ± 3.8 (γ = 17.34 mJ/m[2], 40.2 of dispersive contribution) for C. albicans and H. pylori, respectively, (ii) hydrogen bonds between surface components of yeast and bacterium (e.g., -S-H⋅⋅⋅NH2- or -S-H⋅⋅⋅O[bond, double bond]CO-) and (iii) thiol-mediated surface interactions identified by displacements to lower wavenumbers (Δv = 5 cm[-1]). Evidence of internalization and electrostatic interactions were not evidenced. All observations were congruent with the biofilm formation, including the identification of small-size biostructures (i.e., 122-459 nm) associated with extracellular proteins, extracellular DNA, or outer membrane vesicles were observed characteristic of biofilm formation.

CONCLUSION: It is concluded that biofilm is formed by co-aggregation after anchoring of H. pylori on C. albicans. Several surface interactions were associated with the prevalence of H. pylori, the possibility to find C. albicans in the stomach epithelium infected by H. pylori, but also, strength interactions could be interfering in experimental observations associated with bacterial-DNA detection in culture mixtures.}, } @article {pmid35023082, year = {2022}, author = {da Conceição Aquino de Sá, M and Filho, JTRR and Alcantara, ME and da Costa Silva, M and Dos Santos, MM and Dos Santos, AS and da Costa, MM and Meyer, R}, title = {Analysis of Gtpases Rab 5 and Rab 7 expression from macrophages infected with biofilm-producing and non biofilm-producing strains of Corynebacterium pseudotuberculosis.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {1}, pages = {447-453}, pmid = {35023082}, issn = {1678-4405}, mesh = {Animals ; Biofilms ; *Corynebacterium Infections/microbiology ; *Corynebacterium pseudotuberculosis/genetics ; Macrophages ; Phagocytosis ; rab GTP-Binding Proteins/genetics/metabolism ; }, abstract = {Corynebacterium pseudotuberculosis is a facultative intracellular pathogen that uses various mechanisms to survive within macrophages. In phagocytosis, this survival can be attributed to the ability to inhibit phagosome-lysosome fusion. In this fusion, some proteins, including Rabs GTPases, are involved in the maturation process and are responsible for regulating membrane vesicle trafficking. Thus, to better understand these mechanisms, the capacity of biofilm-producing and non biofilm-producing strains of Corynebacterium pseudotuberculosis for modulating the expression of endosomal proteins GTPases Rab 5 and Rab 7 was evaluated in an in vitro study of infection of goat macrophages. Blood was collected from ten Canindé goats, infected with biofilm-producing and non biofilm-producing strains of C. pseudotuberculosis. Blood cells were separated in colloidal silica-polyvinylpyrrolidone gradients (GE Healthcare®). These cells were maintained at 37 °C, with 5% of CO2. After differentiation, macrophages were infected with the mentioned strains. The bacterial pellets were marked with Rab 5 and Rab 7 antibodies, and their expression was observed by flow cytometry. Both strains of C. pseudotuberculosis (biofilm-producing and non biofilm-producing) were observed to be capable of altering the expression of Rab proteins in macrophages cultivated in vitro. Macrophages from the animals infected with the biofilm-producing strain had an increase in the expression of Rab 5 protein, mainly when these macrophages were treated with the non biofilm-producing strain. The same mechanism was shown to function with Rab 7 protein, however at a lower intensity of expression when compared with Rab 5.}, } @article {pmid35020448, year = {2022}, author = {Nair, S and Li, C and Mou, S and Zhang, Z and Zhang, Y}, title = {A Novel Phage Indirectly Regulates Diatom Growth by Infecting a Diatom-Associated Biofilm-Forming Bacterium.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {5}, pages = {e0213821}, pmid = {35020448}, issn = {1098-5336}, mesh = {Bacteria/genetics ; *Bacteriophages/genetics ; Biofilms ; *Diatoms ; Genome, Viral ; Phylogeny ; }, abstract = {Algae and heterotrophic bacteria have close and intricate interactions, which are regulated by multiple factors in the natural environment. Phages are the major factor determining bacterial mortality rates. However, their impacts on the alga-associated bacteria and thus on the alga-bacterium interactions are poorly understood. Here, we obtained a diatom-associated bacterium, Stappia indica SNL01, that could form a biofilm and had an inhibitory effect on the growth of the diatom Thalassiosira pseudonana. Meanwhile, phage SI01, with a double-stranded circular DNA genome (44,247 bp), infecting S. indica SNL01 was isolated. Phylogenetic analysis revealed that phage SI01 represents a novel member of the Podoviridae family. The phage contained multiple lysis genes encoding cell wall-lysing muramidase and spore cortex-lysing SleB, as well as depolymerase-like tail spike protein. By lysing the host bacterium and inhibiting the formation of biofilm, this phage could indirectly promote the growth of the diatom. Our results provide new insights into how phages indirectly regulate algal growth by infecting bacteria that are closely associated with algae or in the phycosphere. IMPORTANCE The impact of phage infection on the alga-bacterium relationship in the ocean is poorly understood. Here, a novel phage infecting the diatom-associated bacterium Stappia indica SNL01 was isolated. This bacterium could form a biofilm and had a negative effect on diatom growth. We revealed that this phage contained multiple lysis genes and could inhibit the formation of the bacterial biofilm, thus indirectly promoting diatom growth. This study suggests that phages not only are important regulators of bacteria but also have substantial indirect effects on algae and the alga-bacterium relationship.}, } @article {pmid35019768, year = {2022}, author = {Oliveira, F and Lima, T and Correia, A and Silva, AM and Soares, C and Morais, S and Weißelberg, S and Vilanova, M and Rohde, H and Cerca, N}, title = {Involvement of the Iron-Regulated Loci hts and fhuC in Biofilm Formation and Survival of Staphylococcus epidermidis within the Host.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0216821}, pmid = {35019768}, issn = {2165-0497}, mesh = {Animals ; Bacteremia/*microbiology ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cation Transport Proteins/genetics/*metabolism ; Humans ; Iron/*metabolism ; Macrophages/microbiology ; Mice ; Mice, Inbred BALB C ; Multigene Family ; RAW 264.7 Cells ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/genetics/growth & development/*physiology ; }, abstract = {Staphylococcus epidermidis is a major nosocomial pathogen with a remarkable ability to persist on indwelling medical devices through biofilm formation. Nevertheless, it remains intriguing how this process is efficiently achieved under the host's harsh conditions, where the availability of nutrients, such as essential metals, is scarce. Following our previous identification of two iron-regulated loci putatively involved in iron transport, hts and fhuC, we assessed here their individual contribution to both bacterial physiology and interaction with host immune cells. Single deletions of the hts and fhuC loci led to marked changes in the cell iron content, which were partly detrimental for planktonic growth and strongly affected biofilm formation under iron-restricted conditions. Deletion of each of these two loci did not lead to major changes in S. epidermidis survival within human macrophages or in an ex vivo human blood model of bloodstream infection. However, the lack of either hts or fhuC loci significantly impaired bacterial survival in vivo in a murine model of bacteremia. Collectively, this study establishes, for the first time, the pivotal role of the iron-regulated loci hts and fhuC in S. epidermidis biofilm formation and survival within the host, providing relevant information for the development of new targeted therapeutics against this pathogen. IMPORTANCE Staphylococcus epidermidis is one of the most important nosocomial pathogens and a major cause of central line-associated bloodstream infections. Once in the bloodstream, this bacterium must surpass severe iron restriction in order to survive and establish infection. Surprisingly, very little is known about the iron acquisition mechanisms in this species. This study represents the first report on the involvement of the S. epidermidis iron-regulated loci hts and fhuC in biofilm formation under host relevant conditions and, most importantly, in survival within the host. Ultimately, these findings highlight iron acquisition and these loci in particular, as potential targets for future therapeutic strategies against biofilm-associated S. epidermidis infections.}, } @article {pmid35019684, year = {2022}, author = {Hwang, HJ and Li, XH and Kim, SK and Lee, JH}, title = {Anthranilate Acts as a Signal to Modulate Biofilm Formation, Virulence, and Antibiotic Tolerance of Pseudomonas aeruginosa and Surrounding Bacteria.}, journal = {Microbiology spectrum}, volume = {10}, number = {1}, pages = {e0146321}, pmid = {35019684}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms/drug effects ; Humans ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/pathogenicity/*physiology ; Salmonella enterica/drug effects/genetics/metabolism ; Staphylococcus aureus/drug effects/genetics/metabolism ; Virulence ; ortho-Aminobenzoates/*metabolism ; }, abstract = {Anthranilate is a diffusible molecule produced by Pseudomonas aeruginosa and accumulates as P. aeruginosa grows. Anthranilate is an important intermediate for the synthesis of tryptophan and the Pseudomonas quinolone signal (PQS), as well as metabolized by the anthranilate dioxygenase complex (antABC operon products). Here we demonstrate that anthranilate is a key factor that modulates the pathogenicity-related phenotypes of P. aeruginosa and other surrounding bacteria in the environment, such as biofilm formation, antibiotic tolerance, and virulence. We found that the anthranilate levels in P. aeruginosa cultures rapidly increased in the stationary phase and then decreased again, forming an anthranilate peak. Biofilm formation, antibiotic susceptibility, and virulence of P. aeruginosa were significantly altered before and after this anthranilate peak. In addition, these phenotypes were all modified by the mutation of antABC and exogenous addition of anthranilate. Anthranilate also increased the antibiotic susceptibility of other species of bacteria, such as Escherichia coli, Salmonella enterica, Bacillus subtilis, and Staphylococcus aureus. Before the anthranilate peak, the low intracellular anthranilate level was maintained through degradation from the antABC function, in which induction of antABC was also limited to a small extent. The premature degradation of anthranilate, due to its high levels, and antABC expression early in the growth phase, appears to be toxic to the cells. From these results, we propose that by generating an anthranilate peak as a signal, P. aeruginosa may induce some sort of physiological change in surrounding cells. IMPORTANCE Pseudomonas aeruginosa is a notorious pathogen with high antibiotic resistance, strong virulence, and ability to cause biofilm-mediated chronic infection. We found that these characteristics change profoundly before and after the time when anthranilate is produced as an "anthranilate peak". This peak acts as a signal that induces physiological changes in surrounding cells, decreasing their antibiotic tolerance and biofilm formation. This study is important in that it provides a new insight into how microbial signaling substances can induce changes in the pathogenicity-related phenotypes of cells in the environment. In addition, this study shows that anthranilate can be used as an adjuvant to antibiotics.}, } @article {pmid35018500, year = {2022}, author = {Difloe-Geisert, JC and Fiedler, S and Kulik, EM and Schlueter, N and Ganss, C and Walter, C}, title = {Interdental biofilm reduction and composition after use of an activated and inactivated side-to-side toothbrush - a proof-of-principle clinical study.}, journal = {Clinical oral investigations}, volume = {26}, number = {3}, pages = {2909-2919}, pmid = {35018500}, issn = {1436-3771}, support = {304-18//Schweizerische Zahnärzte-Gesellschaft/ ; }, mesh = {Adult ; *Biofilms ; Dental Plaque Index ; Equipment Design ; Humans ; RNA, Ribosomal, 16S ; *Toothbrushing ; Young Adult ; }, abstract = {OBJECTIVES: To evaluate interdental biofilm reduction and composition after powered toothbrushing with a side-to-side (sonic) toothbrush compared to manual toothbrushing following single brushing exercises in periodontally healthy young adults.

MATERIALS AND METHODS: All participants brushed with a side-to-side toothbrush without toothpaste in four different modes: toothbrush (a) inactivated without instruction (OFF-NI), (b) activated without instruction (ON-NI), (c) inactivated with instruction (OFF-I), and (d) activated with instruction (ON-I) at consecutive visits (single brushing exercises). Before and after brushing, the Approximal Plaque Index (API) was assessed at three interdental spaces and plaque samples were taken from two interdental sites. Biofilm reduction and composition were analyzed microbiologically by total bacterial load and 16S rRNA sequencing.

RESULTS: Thirty participants (age: 22.9 ± 2.5 years) completed the study. Most participants showed no or incomplete plaque removal assessed by API following single brushing exercises, while the frequency of API reduction was higher after ON-NI compared to OFF-I (p = 0.023). Irrespective of the brushing mode, a significant reduction of total bacterial load was detected with lower bacterial counts after OFF-NI compared to ON-NI (p = 0.008) and ON-I (p = 0.007). Biofilm composition showed slight changes in the relative abundances of bacterial taxa, regardless of the brushing mode.

CONCLUSIONS: Manual and powered toothbrushing with a side-to-side toothbrush, with and without instruction, showed incomplete interdental biofilm removal in periodontally healthy young adults following single brushing exercises.

CLINICAL RELEVANCE: Data has to be validated in further studies on other groups, however, in periodontally healthy young adults, additional devices seem to be necessary for sufficient interdental cleaning.}, } @article {pmid35018025, year = {2021}, author = {Shreya, and Jain, G and Srinkhala, and Singh, P and Agarwal, K}, title = {Comparative Evaluation of Antimicrobial Efficacy of Calcium Hydroxide, Triple Antibiotic Paste, and 2% Chlorhexidine Combined with 0.5% Cetrimide against Enterococcus faecalis Biofilm-Infected Dentin Model: An In vitro Study.}, journal = {Journal of pharmacy & bioallied sciences}, volume = {13}, number = {Suppl 2}, pages = {S1538-S1543}, pmid = {35018025}, issn = {0976-4879}, abstract = {BACKGROUND: Enterococcus faecalis is the most common and important microorganism found in infected root canals associated with persistent periapical periodontitis and failing endodontically treated tooth. Intracanal medicaments used after chemomechanical preparation of an infected root canal play a vital in eradication of this microorganism and pave the way for long-term success of endodontic therapy. Hence, the present in vitro study was conducted to assess the antimicrobial efficacy of calcium hydroxide (Ca(OH)2), triple antibiotic paste (metronidazole 400 mg + minocycline 100 mg + ciprofloxacin 500 mg), and 2% chlorhexidine (CHX) combined with 0.5% cetrimide on eradication of E. faecalis biofilm.

MATERIALS AND METHODS: Eighty dentin specimens were taken and infected extraorally with E. faecalis to induce microbial colonization. The specimens were then divided into four groups of twenty each based on medicaments used and further subdivided into two subgroups based on assessment of live cells done either immediately after the elimination of the medicament or after 24-h incubation in brain-heart infusion (BHI) medium: Group I specimens were treated with Ca(OH)2, Group II with triple antibiotic paste, Group III with 2% CHX combined with 0.5% cetrimide, and Group IV with saline (control) for 7 days at 37°C. Assessment of live cells was done using confocal microscope.

RESULTS: 2% CHX combined with 0.5% cetrimide (Group III) and triple antibiotic paste (Group II) showed a statistically significant result with high antimicrobial efficacy and lower percentage of live cells as compared to Ca(OH)2 (Group I). The mean percentage of live cells in Group I immediately after elimination of medicaments was 64.7%, in Group II was 1.52%, in Group III was 1.49%, and in Group IV was 83.4%. After 24 h of incubation in BHI medium, 2% CHX combined with 0.5% cetrimide (Group III) showed a statistically significant (p < 0.05) result of 1.27% mean live cells as compared to 84.2% in Ca(OH)2 (Group I), 1.82% in triple antibiotic paste (Group II), and 94.2% in saline (Group IV control).

CONCLUSION: 2% CHX combined with 0.5% cetrimide exhibited maximum antimicrobial efficacy with least number of mean live cells followed by triple antibiotic paste as compared to Ca(OH)2. Based on these findings, 2% CHX combined with 0.5% cetrimide was most effective in eradicating E. faecalis from the extraorally infected dentine biofilm.}, } @article {pmid35017833, year = {2021}, author = {Al-Marri, T and Al-Marri, A and Al-Zanbaqi, R and Ajmi, AA and Fayez, M}, title = {Multidrug resistance, biofilm formation, and virulence genes of Escherichia coli from backyard poultry farms.}, journal = {Veterinary world}, volume = {14}, number = {11}, pages = {2869-2877}, pmid = {35017833}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Backyard chicken flocks have traditionally been regarded as an essential food source in developed countries; however, they may act as reservoirs and spread various zoonotic bacterial pathogens. This study was designed to investigate the prevalence, phenotypic resistance, biofilm formation (BF), and pathotypes of Escherichia coli isolates from backyard poultry farms.

MATERIALS AND METHODS: Cloacal swabs (n=150) and internal organs (n=150) were collected from 30 backyard chicken flocks; 20 of them were experiencing systemic infection, and the other ten were apparently healthy. Samples were bacteriologically examined for E. coli isolation. Isolates were identified biochemically by the VITEK[®] 2 COMPACT system (BioMérieux, France). For molecular identification, 16S rRNA was amplified and sequenced. Ten antimicrobials were selected for E. coli antimicrobial susceptibility testing. The minimum inhibitory concentration for each antimicrobial was determined. The extended-spectrum β-lactamase activity in isolates was investigated using cephalosporin/clavulanate combination disks. The ability of isolates for BF was determined by the microtiter plate method. Thirteen virulence genes linked to different E. coli pathotypes and two serotype-related genes were investigated by real-time polymerase chain reaction.

RESULTS: Eighty-six E. coli strains were isolated from 30 backyard chicken flocks. The isolates were biochemically identified to the species level. Genetically, sequences of the 16S rRNA gene showed >98% identity with E. coli in the National Center for Biological Information database. The frequency of isolation from diseased flocks was significantly higher (p<0.05) than apparently healthy flocks; 63.9% of the isolates were recovered from cloacal swabs and 36.04% were recovered from internal organs. E. coli isolates showed high resistance to ampicillin (AMP; 75.6%), gentamicin (39.5%), and tetracycline (29.1%). However, none of the isolates were resistant to imipenem. A variable drug resistance profile for E. coli isolates was reported. Twenty-one (24.4%) isolates were sensitive to all ten antimicrobials. Seven (8.1%) isolates were resistant only to AMP, and 28 (32.6%) were resistant to two antimicrobials, whereas the remaining 30 (34.9%) isolates showed multidrug resistance (MDR). Of the 86 isolates, 8 (9.3%) were confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli by the combination disk diffusion method. All ESBL isolates were MDR with an MDR index of 0.5-0.6. Fifty-seven (66.3%) isolates were capable of forming biofilms; 22 (25.6%) of them were strong biofilm producers, 24 (27.9%) moderate producers, and 11 (12.8%) weak producers. A statistically significant pairwise correlation was obtained for MDR versus BF (r=0.512) and MDR index versus BF (r=0.556). Based on virulence gene profiles, five pathotypes were identified, including enteropathogenic E. coli (39.5%), avian pathogenic E. coli (32.53%), enterohemorrhagic E. coli (EHEC; 9.3%), enterotoxigenic E. coli (ETEC; 5.8%), and enteroaggregative E. coli (EAEC; 1.2%). The lower frequency of EAEC and ETEC was statistically significant than other pathotypes. Three isolates were identified as O157 based on the detection of the rbfO157 gene.

CONCLUSION: This study reported a high prevalence of MDR, suggesting the misuse of antimicrobials in backyard chicken farms. The emergence of ESBL and EHEC isolates in backyard chickens is a public health concern. Furthermore, the backyard flocks environment may harbor different pathogenic bacteria that may enhance the persistence of infection and the transmission to in-contact humans. Regular monitoring for the occurrence of MDR and the zoonotic pathotypes among E. coli in backyard chicken flocks is recommended, as these bacteria can transmit to humans through food products or contaminated environments.}, } @article {pmid35015140, year = {2022}, author = {Ye, Z and Silva, DM and Traini, D and Young, P and Cheng, S and Ong, HX}, title = {An adaptable microreactor to investigate the influence of interfaces on Pseudomonas aeruginosa biofilm growth.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {3}, pages = {1067-1077}, pmid = {35015140}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents ; Biofilms ; Ciprofloxacin/pharmacology ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections ; *Pseudomonas aeruginosa ; }, abstract = {Biofilms are ubiquitous and notoriously difficult to eradicate and control, complicating human infections and industrial and agricultural biofouling. However, most of the study had used the biofilm model that attached to solid surface and developed in liquid submerged environments which generally have neglected the impact of interfaces. In our study, a reusable dual-chamber microreactor with interchangeable porous membranes was developed to establish multiple growth interfaces for biofilm culture and test. Protocol for culturing Pseudomonas aeruginosa (PAO1) on the air-liquid interface (ALI) and liquid-liquid interface (LLI) under static environmental conditions for 48 h was optimized using this novel device. This study shows that LLI model biofilms are more susceptible to physical disruption compared to ALI model biofilm. SEM images revealed a unique "dome-shaped" microcolonies morphological feature, which is more distinct on ALI biofilms than LLI. Furthermore, the study showed that ALI and LLI biofilms produced a similar amount of extracellular polymeric substances (EPS). As differences in biofilm structure and properties may lead to different outcomes when using the same eradication approaches, the antimicrobial effect of an antibiotic, ciprofloxacin (CIP), was chosen to test the susceptibility of a 48-h-old P. aeruginosa biofilms grown on ALI and LLI. Our results show that the minimum biofilm eradication concentration (MBEC) of 6-h CIP exposure for ALI and LLI biofilms is significantly different, which are 400 μg/mL and 200 μg/mL, respectively. These results highlight the importance of growth interface when developing more targeted biofilm management strategies, and our novel device provides a promising tool that enables manipulation of realistic biofilm growth. KEY POINTS: • A novel dual-chamber microreactor device that enables the establishment of different interfaces for biofilm culture has been developed. • ALI model biofilms and LLI model biofilms show differences in resistance to physical disruption and antibiotic susceptibility.}, } @article {pmid35014948, year = {2022}, author = {Keefe, BF and Bermudez, LE}, title = {Environment in the lung of cystic fibrosis patients stimulates the expression of biofilm phenotype in Mycobacterium abscessus.}, journal = {Journal of medical microbiology}, volume = {71}, number = {1}, pages = {}, doi = {10.1099/jmm.0.001467}, pmid = {35014948}, issn = {1473-5644}, mesh = {*Biofilms ; *Cystic Fibrosis/complications ; Humans ; Lung/*microbiology ; Magnesium ; *Mycobacterium Infections, Nontuberculous ; *Mycobacterium abscessus/genetics ; Phenotype ; }, abstract = {Introduction. Pulmonary infections caused by organisms of the Mycobacterium abscessus complex are increasingly prevalent in populations at risk, such as patients with cystic fibrosis, bronchiectasis and emphysema.Hypothesis. M. abscessus infection of the lung is not observed in immunocompetent individuals, which raises the possibility that the compromised lung environment is a suitable niche for the pathogen to thrive in due to the overproduction of mucus and high amounts of host cell lysis.Aim. Evaluate the ability of M. abscessus to form biofilm and grow utilizing in vitro conditions as seen in immunocompromised lungs of patients.Methodology. We compared biofilm formation and protein composition in the presence and absence of synthetic cystic fibrosis medium (SCFM) and evaluated the bacterial growth when exposed to human DNA.Results. M. abscessus is capable of forming biofilm in SCFM. By eliminating single components found in the medium, it became clear that magnesium works as a signal for the biofilm formation, and chelation of the divalent cations resulted in the suppression of biofilm formation. Investigation of the specific proteins expressed in the presence of SCFM and in the presence of SCFM lacking magnesium revealed many different proteins between the conditions. M. abscessus also exhibited growth in SCFM and in the presence of host cell DNA, although the mechanism of DNA utilization remains unclear.Conclusions. In vitro conditions mimicking the airways of patients with cystic fibrosis appear to facilitate M. abscessus establishment of infection, and elimination of magnesium from the environment may affect the ability of the pathogen to establish infection.}, } @article {pmid35014421, year = {2021}, author = {Herzberg, M and Berglin, M and Eliahu, S and Bodin, L and Agrenius, K and Zlotkin, A and Svenson, J}, title = {Efficient Prevention of Marine Biofilm Formation Employing a Surface-Grafted Repellent Marine Peptide.}, journal = {ACS applied bio materials}, volume = {4}, number = {4}, pages = {3360-3373}, doi = {10.1021/acsabm.0c01672}, pmid = {35014421}, issn = {2576-6422}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/drug effects ; Cnidarian Venoms/chemistry/*pharmacology ; Materials Testing ; Microbial Sensitivity Tests ; Particle Size ; Peptides/chemistry/*pharmacology ; Protein Conformation ; Sea Anemones/chemistry ; Surface Properties ; }, abstract = {Creation of surfaces resistant to the formation of microbial biofilms via biomimicry has been heralded as a promising strategy to protect a range of different materials ranging from boat hulls to medical devices and surgical instruments. In our current study, we describe the successful transfer of a highly effective natural marine biofilm inhibitor to the 2D surface format. A series of cyclic peptides inspired by the natural equinatoxin II protein produced by Beadlet anemone (Actinia equine) have been evaluated for their ability to inhibit the formation of a mixed marine microbial consortium on polyamide reverse osmosis membranes. In solution, the peptides are shown to effectively inhibit settlement and biofilm formation in a nontoxic manner down to 1 nM concentrations. In addition, our study also illustrates how the peptides can be applied to disperse already established biofilms. Attachment of a hydrophobic palmitic acid tail generates a peptide suited for strong noncovalent surface interactions and allows the generation of stable noncovalent coatings. These adsorbed peptides remain attached to the surface at significant shear stress and also remain active, effectively preventing the biofilm formation over 24 h. Finally, the covalent attachment of the peptides to an acrylate surface was also evaluated and the prepared coatings display a remarkable ability to prevent surface colonization at surface loadings of 55 ng/cm[2] over 48 h. The ability to retain the nontoxic antibiofilm activity, documented in solution, in the covalent 2D-format is unprecedented, and this natural peptide motif displays high potential in several material application areas.}, } @article {pmid35014320, year = {2021}, author = {Dai, X and Ma, J and Chen, N and Cai, Y and He, Y and Li, X and Gao, F}, title = {MSNs-Based Nanocomposite for Biofilm Imaging and NIR-Activated Chem/Photothermal/Photodynamic Combination Therapy.}, journal = {ACS applied bio materials}, volume = {4}, number = {3}, pages = {2810-2820}, doi = {10.1021/acsabm.1c00034}, pmid = {35014320}, issn = {2576-6422}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/drug effects ; Copper/chemistry/pharmacology ; Fluorescein-5-isothiocyanate/chemistry/pharmacology ; Infrared Rays ; Male ; Materials Testing ; Microbial Sensitivity Tests ; Nanocomposites/chemistry ; Particle Size ; *Photochemotherapy ; Porosity ; Pseudomonas aeruginosa/*drug effects ; Rats ; Rats, Sprague-Dawley ; Silicon Dioxide/chemistry/pharmacology ; Staphylococcus aureus/*drug effects ; Sulfides/chemistry/pharmacology ; Surface Properties ; }, abstract = {Bacterial infections caused by biofilms are severe clinical problems, resulting in high drug resistance by limiting the penetration of antibiotics. Herein, a near-infrared (NIR)-activated chem/photodynamic/photothermal combined therapeutic agent is proposed by loading fluorescein isothiocyanate (FITC), ultrasmall copper sulfide nanoparticles (Cu2-xSNPs), and ε-polylysine (PLL) onto mesoporous silica nanoparticles (MSNs) through a layer-by-layer self-assembly approach. FITC-doped MSNs are prepared to monitor the permeability and accumulation of nanocomposites into biofilms. MSNs can also act as hosts for the synthesis of ultrasmall Cu2-xSNPs, which has effective photodynamic and photothermal ablation against bacteria under NIR light irradiation. Moreover, biodegradable PLL introduced can not only enhance adhesion toward the bacterial surface to increase the effectiveness of phototherapy but also damage bacteria through electrostatic interaction. As a result, the prepared nanocomposites could not only penetrate biofilms but also ablate biofilms through combined chem/photodynamic/photothermal effects under NIR light irradiation. Furthermore, the nanocomposites could treat bacterial infections in vivo with negligible tissue toxicity. Overall, the finely designed nanocomposites are anticipated to display promising applications in imaging-guided chem/photodynamic/photothermal combined therapy for bacterial infections.}, } @article {pmid35012345, year = {2022}, author = {Chen, Z and Srivastava, P and Zarazúa-Osorio, B and Marathe, A and Fujita, M and Igoshin, OA}, title = {Bacillus subtilis Histidine Kinase KinC Activates Biofilm Formation by Controlling Heterogeneity of Single-Cell Responses.}, journal = {mBio}, volume = {13}, number = {1}, pages = {e0169421}, pmid = {35012345}, issn = {2150-7511}, mesh = {Histidine Kinase/metabolism ; *Protein Kinases/genetics ; *Bacillus subtilis/genetics ; Transcription Factors/metabolism ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; Phosphorylation ; Biofilms ; Spores, Bacterial/genetics ; }, abstract = {In Bacillus subtilis, biofilm and sporulation pathways are both controlled by a master regulator, Spo0A, which is activated by phosphorylation via a phosphorelay-a cascade of phosphotransfer reactions commencing with autophosphorylation of histidine kinases KinA, KinB, KinC, KinD, and KinE. However, it is unclear how the kinases, despite acting via the same regulator, Spo0A, differentially regulate downstream pathways, i.e., how KinA mainly activates sporulation genes and KinC mainly activates biofilm genes. In this work, we found that KinC also downregulates sporulation genes, suggesting that KinC has a negative effect on Spo0A activity. To explain this effect, with a mathematical model of the phosphorelay, we revealed that unlike KinA, which always activates Spo0A, KinC has distinct effects on Spo0A at different growth stages: during fast growth, KinC acts as a phosphate source and activates Spo0A, whereas during slow growth, KinC becomes a phosphate sink and contributes to decreasing Spo0A activity. However, under these conditions, KinC can still increase the population-mean biofilm matrix production activity. In a population, individual cells grow at different rates, and KinC would increase the Spo0A activity in the fast-growing cells but reduce the Spo0A activity in the slow-growing cells. This mechanism reduces single-cell heterogeneity of Spo0A activity, thereby increasing the fraction of cells that activate biofilm matrix production. Thus, KinC activates biofilm formation by controlling the fraction of cells activating biofilm gene expression. IMPORTANCE In many bacterial and eukaryotic systems, multiple cell fate decisions are activated by a single master regulator. Typically, the activities of the regulators are controlled posttranslationally in response to different environmental stimuli. The mechanisms underlying the ability of these regulators to control multiple outcomes are not understood in many systems. By investigating the regulation of Bacillus subtilis master regulator Spo0A, we show that sensor kinases can use a novel mechanism to control cell fate decisions. By acting as a phosphate source or sink, kinases can interact with one another and provide accurate regulation of the phosphorylation level. Moreover, this mechanism affects the cell-to-cell heterogeneity of the transcription factor activity and eventually determines the fraction of different cell types in the population. These results demonstrate the importance of intercellular heterogeneity for understanding the effects of genetic perturbations on cell fate decisions. Such effects can be applicable to a wide range of cellular systems.}, } @article {pmid35011409, year = {2021}, author = {Suttasattakrit, K and Khamkeaw, A and Tangwongsan, C and Pavasant, P and Phisalaphong, M}, title = {Ionic Silver and Electrical Treatment for Susceptibility and Disinfection of Escherichia coli Biofilm-Contaminated Titanium Surface.}, journal = {Molecules (Basel, Switzerland)}, volume = {27}, number = {1}, pages = {}, pmid = {35011409}, issn = {1420-3049}, support = {the 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund)//Chulalongkorn University/ ; }, mesh = {Animals ; Biofilms/*drug effects ; Cell Line ; Disinfectants/*chemistry/*pharmacology ; Disinfection/*methods ; Electricity ; Electrodes ; Escherichia coli/*drug effects/ultrastructure ; Hydrogen-Ion Concentration ; Ions/*chemistry ; Mice ; Microscopy, Atomic Force ; Silver/*chemistry ; Surface Properties ; *Titanium ; }, abstract = {In this work, surface disinfection and biofilm susceptibility were investigated by applying ionic silver of 0.4-1.6 µg/mL and cathodic voltage-controlled electrical treatment of 1.8 V and a current of 30 mA to Escherichia coli (E. coli) ATCC 25922 biofilm-contaminated titanium substrates. Herein, it is evident that the treatment exhibited the potential use to enhance the susceptibility of bacterial biofilms for surface disinfection. In vitro studies have demonstrated that the ionic silver treatment of 60 min significantly increased the logarithmic reduction (LR) of bacterial populations on disinfectant-treated substrates and the electrical treatment enhanced the silver susceptibility of E. coli biofilms. The LR values after the ionic silver treatments and the electric-enhanced silver treatments were in the ranges of 1.94-2.25 and 2.10-2.73, respectively. The treatment was also associated with morphological changes in silver-treated E. coli cells and biofilm-contaminated titanium surfaces. Nevertheless, the treatments showed no cytotoxic effects on the L929 mouse skin fibroblast cell line and only a slight decrease in pH was observed during the electrical polarization of titanium substrate.}, } @article {pmid35010139, year = {2021}, author = {Wang, X and Li, W and Xu, M and Tian, J and Li, W}, title = {The Microbial Diversity and Biofilm-Forming Characteristic of Two Traditional Tibetan Kefir Grains.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35010139}, issn = {2304-8158}, support = {BK20201320//Natural Science Foundation of Jiangsu Province/ ; CX(20)3043//Jiangsu Agriculture Science and Technology Innovation Fund/ ; U1903108 and 31871771//National Natural Science Foundation of China/ ; BK2020305 and XZ-SZ202032//Jiangsu Provincial Key Research and Development Program/ ; QLGC//Qing Lan Project of Jiangsu Province/ ; PARD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; }, abstract = {In this study, a high-throughput sequencing technique was used to analyze bacterial and fungal diversity of two traditional Tibetan kefir grains from Linzhi (K1) and Naqu (K2) regions. Comparative bioinformatic analyses indicated that Lactobacillus kefiranofaciens, L. kefiri and Kluyveromyces marxianus were the main dominant strains in K1 and K2. In order to research the relationship of the growth of kefir grains, the biofilm and the extracellular polysaccharides (EPS) produced by microorganisms, the proliferation rate of kefir grains, the yield and chemical structure of EPS and the optimal days for biofilm formation were determined. The results showed that the growth rate, the yield of EPS and the biofilm formation ability of K1 were higher than K2, and the optimal day of their biofilm formation was the same in 10th day. Additionally, the live cells, dead cells and EPS in biofilm formation of K1 and K2 were observed by fluorescence microscope to clarify the formation process of kefir grains. To determine the influence of microbial interactions on biofilm and the formation of kefir grains, the essential role of microbial quorum sensing needs further attention.}, } @article {pmid35010130, year = {2021}, author = {Pleva, P and Bartošová, L and Máčalová, D and Zálešáková, L and Sedlaříková, J and Janalíková, M}, title = {Biofilm Formation Reduction by Eugenol and Thymol on Biodegradable Food Packaging Material.}, journal = {Foods (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {35010130}, issn = {2304-8158}, support = {CA19124//European Cooperation in Science and Technology/ ; IGA/FT/2022/006//Tomas Bata University in Zlín/ ; }, abstract = {Biofilm is a structured community of microorganisms adhering to surfaces of various polymeric materials used in food packaging. Microbes in the biofilm may affect food quality. However, the presence of biofilm can ensure biodegradation of discarded packaging. This work aims to evaluate a biofilm formation on the selected biodegradable polymer films: poly (lactic acid) (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and poly (butylene succinate) (PBS) by selected bacterial strains; collection strains of Escherichiacoli, Staphylococcusaureus; and Bacillus pumilus, Bacillussubtilis, Bacillustequilensis, and Stenotrophomonasmaltophilia isolated from dairy products. Three different methods for biofilm evaluation were performed: the Christensen method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and fluorescence microscopy. High biofilm formation was confirmed on the control PBS film, whereas low biofilm formation ability was observed on the PLA polymer sample. Furthermore, the films with incorporated antimicrobial compounds (thymol or eugenol) were also prepared. Antimicrobial activity and also reduction in biofilm formation on enriched polymer films were determined. Therefore, they were all proved to be antimicrobial and effective in reducing biofilm formation. These films can be used to prepare novel active food packaging for the dairy industry to prevent biofilm formation and enhance food quality and safety in the future.}, } @article {pmid35007308, year = {2022}, author = {Shu, Y and Liang, D}, title = {Effect of tetracycline on nitrogen removal in Moving Bed Biofilm Reactor (MBBR) System.}, journal = {PloS one}, volume = {17}, number = {1}, pages = {e0261306}, pmid = {35007308}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Bacteria/drug effects/genetics ; Denitrification ; Drug Resistance, Bacterial/genetics ; Kinetics ; Microbiota ; Nitrogen/isolation & purification/*metabolism ; Tetracycline/*chemistry/pharmacology ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry/microbiology ; }, abstract = {The effect of tetracycline (TC) on nitrogen removal in wastewater treatment plants has become a new problem. This study investigated the effects of TC on nitrogen removal using a Moving Bed Biofilm Reactor system. The results showed that there was no significant effect on nitrogen removal performance when the concentration of TC was 5 mg/L, and that the total nitrogen (TN) removal efficiency could reach 75-77%. However, when the concentration of TC increased to 10 mg/L, the denitrification performance was affected and the TN removal efficiency decreased to 58%. The abundance of denitrifying bacteria such as those in the genus Thauera decreased, and TC-resistant bacteria gradually became dominant. At a TC concentration of 10 mg/L, there were also increases and decreases, respectively, in the abundance of resistance and denitrification functional genes. The inhibitory effect of TC on denitrification was achieved mainly by the inhibition of nitrite-reducing bacteria.}, } @article {pmid35007176, year = {2021}, author = {Shadvar, P and Mirzaie, A and Yazdani, S}, title = {Fabrication and optimization of amoxicillin-loaded niosomes: an appropriate strategy to increase antimicrobial and anti-biofilm effects against multidrug-resistant Staphylococcus aureus strains.}, journal = {Drug development and industrial pharmacy}, volume = {47}, number = {10}, pages = {1568-1577}, doi = {10.1080/03639045.2022.2027958}, pmid = {35007176}, issn = {1520-5762}, mesh = {Amoxicillin/pharmacology ; Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents/pharmacology ; HEK293 Cells ; Humans ; Liposomes/chemistry ; *Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; }, abstract = {In this study, different formulations of amoxicillin-loaded niosomes were fabricated using the thin-film hydration method and their physicochemical properties were determined using scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR) spectroscopy. The optimum prepared niosomes had a spherical morphology with an average size of 170.6 ± 6.8 nm and encapsulation efficiency of 65.78 ± 1.45%. The drug release study showed that the release rate of amoxicillin from niosome containing amoxicillin was slow and 47 ± 1% of the drug was released within 8 h, while 97 ± 0.5% of the free drug was released. In addition, amoxicillin-loaded niosome increased the antimicrobial activity by 2-4 folds against multidrug-resistant (MDR) Staphylococcus aureus strains using broth microdilution assay. Moreover, at 1/2 minimum inhibitory concentrations, amoxicillin-loaded niosome significantly enhanced the anti-biofilm activity compared to free amoxicillin. Amoxicillin-loaded niosome had negligible cytotoxicity against HEK-293 normal cell line compared to free amoxicillin. The free niosomes exhibited no toxicity against HEK-293 cells and presented a biocompatible nanoscale delivery system. Based on the results, it can be concluded that amoxicillin-loaded niosome can be used as a promising candidate for enhancing antimicrobial and anti-biofilm effects against MDR strains of S. aureus.}, } @article {pmid35007137, year = {2022}, author = {Kurbatfinski, N and Goodman, SD and Bakaletz, LO}, title = {A Humanized Monoclonal Antibody Potentiates Killing of Diverse Biofilm-Forming Respiratory Tract Pathogens by Antibiotics.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {3}, pages = {e0187721}, pmid = {35007137}, issn = {1098-6596}, support = {/WT_/Wellcome Trust/United Kingdom ; R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; Antibodies, Monoclonal, Humanized/pharmacology ; *Bacterial Infections/microbiology ; Biofilms ; Humans ; Respiratory System ; }, abstract = {New strategies to treat diseases in which biofilms contribute significantly to pathogenesis are needed, as biofilm-resident bacteria are highly recalcitrant to antibiotics due to physical biofilm architecture and a canonically quiescent metabolism, among many additional attributes. We, and others, have shown that when biofilms are dispersed or disrupted, bacteria released from biofilm residence are in a distinct physiologic state that, in part, renders these bacteria highly sensitive to killing by specific antibiotics. We sought to demonstrate the breadth of the ability of a recently humanized monoclonal antibody against an essential biofilm structural element (DNABII protein) to disrupt biofilms formed by respiratory tract pathogens and potentiate antibiotic-mediated killing of bacteria released from biofilm residence. Biofilms formed by six respiratory tract pathogens were significantly disrupted by the humanized monoclonal antibody in a dose- and time-dependent manner, as corroborated by confocal laser scanning microscopy (CLSM) imaging. Bacteria newly released from the biofilms of 3 of 6 species were significantly more sensitive than their planktonic counterparts to killing by 2 of 3 antibiotics currently used clinically and were now also equally as sensitive to killing by the 3rd antibiotic. The remaining 3 pathogens were significantly more susceptible to killing by all 3 antibiotics. A humanized monoclonal antibody directed against protective epitopes of a DNABII protein effectively released six diverse respiratory tract pathogens from biofilm residence in a phenotypic state that was now as, or significantly more, sensitive to killing by three antibiotics currently indicated for use clinically. These data support this targeted, combinatorial, species-agnostic therapy to mitigate chronic bacterial diseases.}, } @article {pmid35007019, year = {2021}, author = {Sikder, A and Chaudhuri, A and Mondal, S and Singh, NDP}, title = {Recent Advances on Stimuli-Responsive Combination Therapy against Multidrug-Resistant Bacteria and Biofilm.}, journal = {ACS applied bio materials}, volume = {4}, number = {6}, pages = {4667-4683}, doi = {10.1021/acsabm.1c00150}, pmid = {35007019}, issn = {2576-6422}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; Bacterial Infections/*drug therapy ; Biofilms/drug effects ; Combined Modality Therapy ; *Drug Delivery Systems ; Drug Resistance, Multiple, Bacterial/drug effects ; Drug Therapy, Combination ; Humans ; }, abstract = {The widespread occurrence of infections from multidrug-resistant (MDR) bacteria is a global health problem. It has been amplified over the past few years due to the increase in adaptive traits in bacteria and lack of advanced treatment strategies. Because of the low bioavailability and limited penetration at infected sites, the existing antibiotics often fail to resist bacterial growth. Recently, developed stimuli-responsive drug delivery systems and combinatorial therapeutic systems based on nanoparticles, metal-organic frameworks, hydrogels, and organic chromophores offer the ability to improve the therapeutic efficacy of antibiotics by reducing drug resistance and other side effects. These therapeutic systems have been designed with the relevant chemical and physical properties that respond to specific triggers resulting in spatiotemporal controlled release and site-specific transportability. This review highlights the latest development of single and dual/multistimuli-responsive antibiotic delivery systems for combination therapies to treat MDR bacterial infections and biofilm eradication.}, } @article {pmid35006805, year = {2021}, author = {Zhang, K and Raju, C and Zhong, W and Pethe, K and Gründling, A and Chan-Park, MB}, title = {Cationic Glycosylated Block Co-β-peptide Acts on the Cell Wall of Gram-Positive Bacteria as Anti-biofilm Agents.}, journal = {ACS applied bio materials}, volume = {4}, number = {5}, pages = {3749-3761}, doi = {10.1021/acsabm.0c01241}, pmid = {35006805}, issn = {2576-6422}, support = {MR/P028225/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biocompatible Materials/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects/growth & development ; Cations/chemical synthesis/chemistry/pharmacology ; Glycosylation ; Gram-Positive Bacteria/*drug effects ; Materials Testing ; Microbial Sensitivity Tests ; Particle Size ; Peptides/chemical synthesis/chemistry/*pharmacology ; Teichoic Acids/chemistry/*pharmacology ; }, abstract = {Antimicrobial resistance is a global threat. In addition to the emergence of resistance to last resort drugs, bacteria escape antibiotics killing by forming complex biofilms. Strategies to tackle antibiotic resistance as well as biofilms are urgently needed. Wall teichoic acid (WTA), a generic anionic glycopolymer present on the cell surface of many Gram-positive bacteria, has been proposed as a possible therapeutic target, but its druggability remains to be demonstrated. Here we report a cationic glycosylated block co-β-peptide that binds to WTA. By doing so, the co-β-peptide not only inhibits biofilm formation, it also disperses preformed biofilms in several Gram-positive bacteria and resensitizes methicillin-resistant Staphylococcus aureus to oxacillin. The cationic block of the co-β-peptide physically interacts with the anionic WTA within the cell envelope, whereas the glycosylated block forms a nonfouling corona around the bacteria. This reduces physical interaction between bacteria-substrate and bacteria-biofilm matrix, leading to biofilm inhibition and dispersal. The WTA-targeting co-β-peptide is a promising lead for the future development of broad-spectrum anti-biofilm strategies against Gram-positive bacteria.}, } @article {pmid35006756, year = {2021}, author = {Woodhouse, I and Nejati, S and Selvamani, V and Jiang, H and Chittiboyina, S and Grant, J and Mutlu, Z and Waimin, J and Abutaleb, NS and Seleem, MN and Rahimi, R}, title = {Flexible Microneedle Array Patch for Chronic Wound Oxygenation and Biofilm Eradication.}, journal = {ACS applied bio materials}, volume = {4}, number = {7}, pages = {5405-5415}, doi = {10.1021/acsabm.1c00087}, pmid = {35006756}, issn = {2576-6422}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria ; *Biofilms ; Humans ; Oxygen/pharmacology ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Swine ; *Wound Infection/drug therapy ; }, abstract = {Chronic nonhealing wounds are a growing socioeconomic problem that affects more than 6 million people annually solely in the United States. These wounds are colonized by bacteria that often develop into biofilms that act as a physical and chemical barrier to therapeutics and tissue oxygenation leading to chronic inflammation and tissue hypoxia. Although wound debridement and vigorous mechanical abrasion techniques are often used by clinical professionals to manage and remove biofilms from wound surfaces, such methods are highly nonselective and painful. In this study, we have developed a flexible polymer composite microneedle array that can overcome the physicochemical barriers (i.e., bacterial biofilm) present in chronic nonhealing wounds and codeliver oxygen and bactericidal agents. The polymeric microneedles are made by using a facile UV polymerization process of polyvinylpyrrolidone and calcium peroxide onto a flexible polyethylene terephthalate substrate for conformable attachment onto different locations of the human body surface. The microneedles effectively elevate the oxygen levels from 8 to 12 ppm once dissolved over the course of 2 h while also providing strong bactericidal effects on both liquid and biofilm bacteria cultures of both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacterial strains commonly found in dermal wounds. Furthermore, the results from the ex vivo assay on a porcine wound model indicated successful insertion of the microneedles into the tissue while also providing effective bactericidal properties against both Gram-positive and Gram-negative within the complex tissue matrix. Additionally, the microneedles demonstrate high levels of cytocompatibility with less than 10% of apoptosis throughout 6 days of continuous exposure to human dermal fibroblast cells. The demonstrated flexible microneedle array can provide a better approach for increasing the effectiveness of topical tissue oxygenation as well as the treatment of infected wounds with intrinsically antibiotic resistant biofilms.}, } @article {pmid35006740, year = {2021}, author = {Fan, X and Zhu, SS and Zhang, XX and Ren, HQ and Huang, H}, title = {Revisiting the Microscopic Processes of Biofilm Formation on Organic Carriers: A Study under Variational Shear Stresses.}, journal = {ACS applied bio materials}, volume = {4}, number = {7}, pages = {5529-5541}, doi = {10.1021/acsabm.1c00344}, pmid = {35006740}, issn = {2576-6422}, mesh = {*Bacterial Adhesion ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Microbiota ; Plastics ; Stress, Mechanical ; }, abstract = {The microscopic process of biofilm development on carriers is critical for interfacial regulation of biofilms in attached-growth wastewater treatment. However, the process under shear stress has not been well understood. The study purposed to revisit the processes of biofilm formation on organic carriers under different shear stresses with special highlights on bacterial reversible adhesion and pioneers in the microbial community. Biofilm formation on high-density polyethylene, polyamide, acrylonitrile butadiene styrene plastic, polyvinyl chloride, and polycarbonate carriers under shear stresses ranging from 1.0 to 2.5 Pa was investigated using Couette-Taylor reactors. Employing extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the bacterial reversible adhesion regions ranging from 3.74 ± 0.20 to 5.51 ± 0.24 nm on an organic carrier were quantified for the first time, elucidating significant differences among different carriers (p < 0.01). The colonization of pioneers in the microbial community was significantly altered by shear stress rather than carrier properties (p < 0.01). In particular, the diversity of the biofilm microbial community was pronouncedly enhanced by a higher shear stress (p < 0.01). XDLVO analysis suggested that extracellular polymeric substances had a negative feedback on subsequent microbial adhesion and biofilm development, especially the transition from reversible to irreversible bacterial adhesion. This study contributed to a better understanding of the biofilm formation process at the microscopic scale and shed light on micro-interfacial manipulation for biofilm accumulation or renewal.}, } @article {pmid35006701, year = {2021}, author = {Gao, H and Wang, J and Wu, H and Xin, F and Zhang, W and Jiang, M and Fang, Y}, title = {Biofilm-Integrated Glycosylated Membrane for Biosuccinic Acid Production.}, journal = {ACS applied bio materials}, volume = {4}, number = {10}, pages = {7517-7523}, doi = {10.1021/acsabm.1c00764}, pmid = {35006701}, issn = {2576-6422}, mesh = {*Biofilms ; Biofuels ; Fermentation ; Glycosylation ; *Succinic Acid/metabolism ; }, abstract = {Biofilm-based cell-immobilized fermentation technology is regarded as the technique with the most potential for biobased product (chemicals, biofuelss materials, etc.) production in industry. Glycosylated membrane can mimic natural extracellular matrix (ECM) and improve cell adhesion and biofilm formation based on carbohydrate-microbial lectin interaction. Here, we applied glycosylated membrane with rhamnose modified surface for constructing Actinobacillus succinogenes biofilm and producing biosuccinic acid. Polymer hollow fiber (PHF) membrane surface was first modified by glycosylation based on physical adsorption approach. The approach is simple, green, and suitable for scale-amplification. Then, the microbial biofilm formed dramatically on the modified membrane surface. And for subsequent biosuccinic acid production, the maximum titer of succinic acid reached 67.3 g/L, and the yield was 0.82 g/g. Compared with free cell fermentation, the titer and yield increased by 18% and 9% in this biofilm-based cell-immobilized fermentation system, respectively. Importantly, the production efficiency of biosuccinic acid increased obviously for subsequent biofilm-based cell-immobilized fermentation. In addition, the biofilm-integrated glycosylated membrane showed high reusability for succinic acid production. This result is important for developing biofilms for a wide range of applications in bioproduct (chemicals, biofuels, materials, etc.) production.}, } @article {pmid35005954, year = {2021}, author = {Seferji, KA and Susapto, HH and Khan, BK and Rehman, ZU and Abbas, M and Emwas, AH and Hauser, CAE}, title = {Green Synthesis of Silver-Peptide Nanoparticles Generated by the Photoionization Process for Anti-Biofilm Application.}, journal = {ACS applied bio materials}, volume = {4}, number = {12}, pages = {8522-8535}, doi = {10.1021/acsabm.1c01013}, pmid = {35005954}, issn = {2576-6422}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/metabolism ; Biofilms ; Escherichia coli ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; *Metal Nanoparticles/chemistry ; Peptides/pharmacology ; *Silver/pharmacology ; }, abstract = {An alarming increase in antibiotic-resistant bacterial strains is driving clinical demand for new antibacterial agents. One of the oldest antimicrobial agents is elementary silver (Ag), which has been used for thousands of years. Even today, elementary Ag is used for medical purposes such as treating burns, wounds, and microbial infections. In consideration of the effectiveness of elementary Ag, the present researchers generated effective antibacterial/antibiofilm agents by combining elementary Ag with biocompatible ultrashort peptide compounds. The innovative antibacterial agents comprised a hybrid peptide bound to Ag nanoparticles (IVFK/Ag NPs). These were generated by photoionizing a biocompatible ultrashort peptide, thus reducing Ag ions to form Ag NPs with a diameter of 6 nm. The IVFK/Ag NPs demonstrated promising antibacterial/antibiofilm activity against reference Gram-positive and Gram-negative bacteria compared with commercial Ag NPs. Through morphological changes in Escherichia coli and Staphylococcus aureus, we proposed that the mechanism of action for IVFK/Ag NPs derives from their ability to disrupt bacterial membranes. In terms of safety, the IVFK/Ag NPs demonstrated biocompatibility in the presence of human dermal fibroblast cells, and concentrations within the minimal inhibitory concentration had no significant effect on cell viability. These results demonstrated that hybrid peptide/Ag NPs hold promise as a biocompatible material with strong antibacterial/antibiofilm properties, allowing them to be applied across a wide range of applications in tissue engineering and regenerative medicine.}, } @article {pmid35004774, year = {2021}, author = {Oliveira, F and Lima, T and Correia, A and Silva, AM and Soares, C and Morais, S and Weißelberg, S and Vilanova, M and Rohde, H and Cerca, N}, title = {Siderophore-Mediated Iron Acquisition Plays a Critical Role in Biofilm Formation and Survival of Staphylococcus epidermidis Within the Host.}, journal = {Frontiers in medicine}, volume = {8}, number = {}, pages = {799227}, pmid = {35004774}, issn = {2296-858X}, abstract = {Iron acquisition through siderophores, a class of small, potent iron-chelating organic molecules, is a widely spread strategy among pathogens to survive in the iron-restricted environment found in the host. Although these molecules have been implicated in the pathogenesis of several species, there is currently no comprehensive study addressing siderophore production in Staphylococcus epidermidis. Staphylococcus epidermidis is an innocuous skin commensal bacterium. The species, though, has emerged as a leading cause of implant-associated infections, significantly supported by an inherent ability to form biofilms. The process of adaptation from skin niche environments to the hostile conditions during invasion is yet not fully understood. Herein, we addressed the possible role of siderophore production in S. epidermidis virulence. We first identified and deleted a siderophore homolog locus, sfaABCD, and provided evidence for its involvement in iron acquisition. Our findings further suggested the involvement of siderophores in the protection against oxidative stress-induced damage and demonstrated the in vivo relevance of a siderophore-mediated iron acquisition during S. epidermidis infections. Conclusively, this study addressed, for the first time in this species, the underlying mechanisms of siderophore production, highlighting the importance of a siderophore-mediated iron acquisition under host relevant conditions and, most importantly, its contribution to survival within the host.}, } @article {pmid35003484, year = {2021}, author = {Hou, X and Yuan, K and Huang, Z and Ma, R}, title = {Effects of Bleaching Associated with Er:YAG and Nd:YAG Laser on Enamel Structure and Bacterial Biofilm Formation.}, journal = {Scanning}, volume = {2021}, number = {}, pages = {6400605}, pmid = {35003484}, issn = {1932-8745}, mesh = {Biofilms ; Dental Enamel ; *Lasers, Solid-State ; *Tooth Bleaching ; }, abstract = {OBJECTIVE: To compare the effects of bleaching associated with Er:YAG and Nd:YAG laser on enamel structure and mixed biofilm formation on teeth surfaces.

MATERIALS AND METHODS: Sixty-eight enamel samples were randomly divided into four groups (n = 17), control, Opalescence Boost only, Opalescence Boost plus Er: YAG laser, and Opalescence Boost plus Nd:YAG laser. The structure was observed using SEM after bleaching. Subsequently, the treated enamel samples were also cultured in suspensions of Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, and Fusobacterium nucleatum (Fn) for 24 and 48 h. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by confocal laser scanning microscopy. The data were analyzed using the Kruskal-Wallis method.

RESULTS: The enamel structure significantly changed after bleaching. There was no obvious difference in the biofilm formation after 24 h; however, after 48 hours, the amount of biofilm increased significantly. Remarkably, the amount was significantly higher on enamel bleached only, however, there was no significant difference between samples bleached with Er:YAG or Nd:YAG laser compared to the control.

CONCLUSIONS: Bleaching only appeared to markedly promote biofilm formation after 48 h, and the biofilms on samples bleached with Er:YAG or Nd:YAG laser did not change significantly, showing that bleaching with Er:YAG or Nd:YAG laser can be safely applied in clinical practice.}, } @article {pmid35003279, year = {2021}, author = {Ma, Z and Li, NA and Ning, C and Liu, Y and Guo, Y and Ji, C and Zhu, X and Meng, Q and Xia, X and Zhang, X and Cai, X and Cai, K and Jun, Q}, title = {A Novel LysR Family Factor STM0859 is Associated with The Responses of Salmonella Typhimurium to Environmental Stress and Biofilm Formation.}, journal = {Polish journal of microbiology}, volume = {70}, number = {4}, pages = {479-487}, pmid = {35003279}, issn = {2544-4646}, mesh = {Bacterial Proteins/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; *Salmonella typhimurium/genetics ; *Stress, Physiological ; Transcription Factors/genetics ; }, abstract = {Salmonella enterica subsp. enterica serovar Typhimurium (ST) is an intracellularly parasitic bacterium. This zoonotic pathogen causes food poisoning and thus imposes a severe threat to food safety. Here, to understand the regulatory roles of the novel transcription factor STM0859 on the response of ST to environmental stress and biofilm formation, the STM0859 gene-deficient strain and the complementation strain ΔSTM0859/STM0859 were generated, respectively. Then, its capacity of responding to environmental stresses and biofilm (BF) formation ability under different stresses, including acid, alkali, high salt, cholate, and oxidative stresses was tested. We further analyzed the interaction between the STM0859 protein and the promoter of the acid stress response-related gene rcsB by performing an electrophoresis mobility shift assay (EMSA). The results showed that acid resistance and BF formation capacities of ST-ΔSTM0859 strain were significantly weaker, as compared with those of Salmonella Typhimurium SL1344 (ST-SL1344) wild strain (p < 0.01). Quantitative qRT-PCR analysis showed that the expression levels of acid stress and BF formation-related genes, rcsB and rpoS, of ST-ΔSTM0859 strain were significantly reduced at the transcription levels, while the transcription levels of these genes were fully restored in complementation strain ST-ΔSTM0859/STM0859. The results of EMSA showed that STM0859 was capable of binding the promoter DNA fragments of the rcsB gene, suggesting that STM0859 can promote the transcription of the rcsB gene through interaction with its promoter, thereby exerting an indirectly regulatory role on the adaptive responses to acid stress and BF formation of ST. This study provided new insights into the regulatory mechanisms of the LysR family factors on the tolerances of ST under adverse environmental stresses.}, } @article {pmid35002990, year = {2021}, author = {Chen, F and Zhang, J and Ji, HJ and Kim, MK and Kim, KW and Choi, JI and Han, SH and Lim, S and Seo, HS and Ahn, KB}, title = {Deinococcus radiodurans Exopolysaccharide Inhibits Staphylococcus aureus Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {712086}, pmid = {35002990}, issn = {1664-302X}, abstract = {Deinococcus radiodurans is an extremely resistant bacterium against extracellular stress owing to on its unique physiological functions and the structure of its cellular constituents. Interestingly, it has been reported that the pattern of alteration in Deinococcus proportion on the skin is negatively correlated with skin inflammatory diseases, whereas the proportion of Staphylococcus aureus was increased in patients with chronic skin inflammatory diseases. However, the biological mechanisms of deinococcal interactions with other skin commensal bacteria have not been studied. In this study, we hypothesized that deinococcal cellular constituents play a pivotal role in preventing S. aureus colonization by inhibiting biofilm formation. To prove this, we first isolated cellular constituents, such as exopolysaccharide (DeinoPol), cell wall (DeinoWall), and cell membrane (DeinoMem), from D. radiodurans and investigated their inhibitory effects on S. aureus colonization and biofilm formation in vitro and in vivo. Among them, only DeinoPol exhibited an anti-biofilm effect without affecting bacterial growth and inhibiting staphylococcal colonization and inflammation in a mouse skin infection model. Moreover, the inhibitory effect was impaired in the Δdra0033 strain, a mutant that cannot produce DeinoPol. Remarkably, DeinoPol not only interfered with S. aureus biofilm formation at early and late stages but also disrupted a preexisting biofilm by inhibiting the production of poly-N-acetylglucosamine (PNAG), a key molecule required for S. aureus biofilm formation. Taken together, the present study suggests that DeinoPol is a key molecule in the negative regulation of S. aureus biofilm formation by D. radiodurans. Therefore, DeinoPol could be applied to prevent and/or treat infections or inflammatory diseases associated with S. aureus biofilms.}, } @article {pmid35002024, year = {2022}, author = {Joseph, B and Steier, L}, title = {Bioluminescence and ventilator-associated pneumonia caused by oral biofilm in ICU during COVID-19 -Is there a possible relationship?.}, journal = {Medical hypotheses}, volume = {159}, number = {}, pages = {110760}, pmid = {35002024}, issn = {1532-2777}, mesh = {Biofilms ; *COVID-19 ; Humans ; Intensive Care Units ; *Pneumonia, Ventilator-Associated ; Respiration, Artificial ; SARS-CoV-2 ; }, abstract = {Ventilator-associated pneumonia (VAP) has been claiming many lives in the intensive care unit (ICU) during COVID-19. Oral biofilm and bacterial contamination that can be passed on from the oral cavity to the lungs during endotracheal intubation has been found to be the main culprit. Bioluminescence-based assays are emerging as potential clinical diagnostics methods. Hence, we hypothesize that the bioluminescent imaging technique can be used in the ICU to determine the load of biofilm-associated with patients undergoing endotracheal intubation. Early detection of such infections and their management can effectively bring down mortality and influence the death rate in ICU caused due to VAP. Government agencies and policymakers should be made to take this issue of deaths in the ICU due to VAP more seriously and act judiciously to methods such as bioluminescence based on sound scientific evidence.}, } @article {pmid35001570, year = {2022}, author = {Astuti Febria, F and Aziza, R}, title = {Exopolysaccharides-Producing Biofilm Bacteria from Submerged Seawater Substrate for Bioremediation of Heavy Metal Contamination.}, journal = {Pakistan journal of biological sciences : PJBS}, volume = {25}, number = {1}, pages = {9-14}, doi = {10.3923/pjbs.2022.9.14}, pmid = {35001570}, issn = {1812-5735}, mesh = {*Biodegradation, Environmental ; Biofilms/*growth & development ; Gram-Negative Bacteria/*growth & development/isolation & purification ; Indonesia ; Metals, Heavy/*toxicity ; Seawater/analysis/*chemistry ; }, abstract = {Background and Objective: The coastal environment is often polluted by various toxic compounds such as heavy metals. Exposure to these toxic compounds causes coastal bacteria to adapt so that they can be used as bioremediation agents for heavy metals. This study aims for finding and screening the ability of bacteria to produce exopolysaccharide biofilms and then determine the characteristics of bacterial isolates as agents candidates for heavy metal bioremediation in the coastal environment. Materials and Methods: Samples were collected on submerged seawater substrate from Bungus Coastal, Padang and West Sumatra, on the wet area that was exposed by seawater (on the rocks, on the wood and the ship, the lower out part on the ship that exposed to seawater). Bacterial isolation process using Marine Agar Medium. The isolate discovered then observed and purified. Furthermore, Congo Red Agar was used for bacteria screening for detecting EPS produced by biofilm bacteria. Results: The results of the isolation, found 9 bacterial isolates attached to the substrate submerged seawater. The screening results showed that isolates K4, K5 and K7 were positive as biofilm-forming bacteria as indicated by the colour change of the bacterial colonies to black on Congo Red Media after 24 hrs incubation. The characteristics of the three bacterial isolates were gram-negative, with cocci and bacilli cells form. Conclusion: Three isolates of positive exopolysaccharide biofilm bacteria that 1 isolate gram-negative coccus (K4) and the other 2 isolates (K5 and K7) were bacillus. Then, the 3 isolates can be used for remediation of metal contamination research in aquatic.}, } @article {pmid35001503, year = {2022}, author = {Tagua, VG and Molina-Henares, MA and Travieso, ML and Nisa-Martínez, R and Quesada, JM and Espinosa-Urgel, M and Ramos-González, MI}, title = {C-di-GMP and biofilm are regulated in Pseudomonas putida by the CfcA/CfcR two-component system in response to salts.}, journal = {Environmental microbiology}, volume = {24}, number = {1}, pages = {158-178}, doi = {10.1111/1462-2920.15891}, pmid = {35001503}, issn = {1462-2920}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; *Escherichia coli Proteins/genetics ; Gene Expression Regulation, Bacterial ; Phosphorus-Oxygen Lyases/genetics/metabolism ; *Pseudomonas putida/genetics/metabolism ; Salts ; }, abstract = {In Pseudomonas putida KT2440, cfcR encodes an orphan multidomain response regulator with diguanylate cyclase activity, which is responsible for the synthesis of c-di-GMP, a second messenger key in the transition from planktonic to sessile bacterial lifestyles. When overexpressed, cfcR enhances biofilm formation and causes other phenotype alterations. The cfcA gene, encoding a membrane-anchored multisensory CHASE3/GAF hybrid histidine kinase (HK), is required to develop this pleiotropic phenotype. Here we show autophosphorylation of CfcA through HisKA/HATPase_c domains and then transfer of the phosphoryl group to an internal receiver (REC) domain. CfcA REC domains are nonessential for phosphotransfer from CfcA~P to the REC domain of CfcR. CfcA~P also phosphorylates the REC domain of CfcD, a second HK encoded in the same gene cluster as CfcA, which negatively regulates the CfcA/CfcR pathway. To evaluate the impact of CfcA domains on CfcR activity, a battery of mutants with in-frame domain deletions was generated, whose CfcA protein locations were also examined. CfcA membrane anchorage contributes to protein stability and CfcR activation. Salt enhances c-di-GMP levels through CfcR, a response which is hampered by alteration of a presumed ligand-binding motif in the CHASE3 sensor domain. Thus, in P. putida, c-di-GMP is salt-regulated through the CfcA/CfcR/CfcD system.}, } @article {pmid35001350, year = {2022}, author = {Vishakha, K and Das, S and Das, SK and Banerjee, S and Ganguli, A}, title = {Antibacterial, anti-biofilm, and anti-virulence potential of tea tree oil against leaf blight pathogen Xanthomonas oryzae pv. oryzae instigates disease suppression.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {1}, pages = {19-32}, pmid = {35001350}, issn = {1678-4405}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; Humans ; *Oryza/microbiology ; Plant Diseases/microbiology/prevention & control ; *Tea Tree Oil/pharmacology ; Virulence ; *Xanthomonas ; }, abstract = {Bacterial leaf blight (BLB) disease, caused by Xanthomonas oryzae pv. oryzae (Xoo), causes major annual economic losses around the world. Inorganic copper compounds and antibiotics are conventionally used to control BLB disease. They often cause environmental pollution, contributing to adverse effects on human health. Therefore, research is now leading to the search for alternative control methods. Tea tree oil (TTO) is obtained from a traditional medicinal plant, Melaleuca alternifolia, with antibacterial properties. In this study, we found that TTO showed antibacterial activity against Xoo with a minimum inhibitory concentration (MIC) of 18 mg/ml. These antagonistic activities were not limited only to planktonic cells, as further studies have shown that TTO effectively eradicated sessile cells of Xoo in both initial and mature biofilms. Furthermore, it was also observed that TTO reduced various key virulence properties of Xoo, such as swimming, swarming motility, and the production of extracellular polymeric substances, xanthomonadin, and exoenzymes. TTO triggered ROS generation with cell membrane damage as an antibacterial mode of action against Xoo. The in silico study revealed that 1,8-cineole of TTO was effectively bound to two essential proteins, phosphoglucomutase and peptide deformylase, responsible for the synthesis of EPS and bacterial survival, respectively. These antibacterial and anti-virulence activities of TTO against Xoo were further confirmed by an ex vivo virulence assay where TTO significantly reduced the lesion length caused by Xoo on rice leaves. All these data concluded that TTO could be a safe, environment-friendly alternative approach for the comprehensive management of BLB disease.}, } @article {pmid34999247, year = {2022}, author = {Zheng, Y and Lu, X and Liu, B and Li, B and Yang, C and Tang, W and Zhang, J}, title = {Novel FabI inhibitor disrupts the biofilm formation of MRSA through down-regulating the expression of quorum-sensing regulatory genes.}, journal = {Microbial pathogenesis}, volume = {163}, number = {}, pages = {105391}, doi = {10.1016/j.micpath.2022.105391}, pmid = {34999247}, issn = {1096-1208}, mesh = {*Aniline Compounds ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Enoyl-(Acyl-Carrier-Protein) Reductase (NADH)/antagonists & inhibitors ; Fatty Acid Synthase, Type II/antagonists & inhibitors ; Genes, Regulator ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Mice ; Microbial Sensitivity Tests ; Quorum Sensing ; Rabbits ; }, abstract = {OBJECTIVES: The aim of this study was to explore the antibiofilm and antivirulence efficacy of benzylaniline 4k against MRSA.

METHODS: The clinical MRSA strains were identified and used to evaluate their potential to form biofilm using crystal violet assay. The minimal inhibitory concentration (MIC) was determined using broth microdilution method. The expression of genes was detected using quantitative real-time PCR (qRT-PCR). Rabbit blood hemolytic assay was used to observe the inhibitory ability of alpha-hemolysin (Hla).

RESULTS: Compound 4k showed potent antibacterial activity against 16 clinical MRSA with an MIC50 of 1.25 mg/L and MIC90 of 2.25 mg/L. The value of minimum biofilm eradication concentration (MBEC) against MRSA2858 biofilm was of 1.5 mg/L, close to its MIC, superior to those of vancomycin and erythromycin. Compound 4k eradicated the formation of biofilm through inhibiting the gene expression of branched-chain fatty acid synthesis, down-regulating the expression of quorum-sensing (QS) regulatory genes (norA, agrA, icaA, hla), decreasing the level of hemolysis in a dose-dependent manner, and inhibiting rabbit blood hemolysis by 86.9% at a concentration of 1.25 mg/L. In a mouse model of abdominal infection, compound 4k was more effective than vancomycin in reducing bacterial load.

CONCLUSIONS: These results suggested that compound 4k could be developed as promising an anti-MRSA agent through affecting quorum-sensing system.}, } @article {pmid34999188, year = {2022}, author = {Zhang, X and Miao, Y and Yu, D and Qiu, Y and Zhao, J and Wang, X}, title = {Culturing partial denitrification biofilm in side stream incubator with ordinary activated sludge as inoculum: One step closer to mainstream Anammox upgrade.}, journal = {Bioresource technology}, volume = {347}, number = {}, pages = {126679}, doi = {10.1016/j.biortech.2022.126679}, pmid = {34999188}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; *Denitrification ; Incubators ; Nitrogen ; Oxidation-Reduction ; Rivers ; *Sewage ; Wastewater ; }, abstract = {Recently, adding carriers into anoxic zone is proposed for mainstream Anammox upgrade, which relied on the denitrifiers responsible for partial denitrification (PD) to generate essential nitrite for Anammox bacteria. Still, their low abundance in the naturally formed biofilm leads to insufficient nitrite supply. This study investigated the sequential culturing of PD biofilm. By inoculating ordinary activated sludge, the PD process was quickly established within 54-day. During that, decreasing carbon to nitrogen ratio and anoxic duration in order might be effective strategies. Adding carriers shifted the microbial community, especially the proliferation of Flavobacterium. When solely using the mature PD biofilm, high nitrate to nitrite transformation ratio (>70%) was obtained. Meanwhile, both nitrate-reducing and nitrite-generating processes slowed down and lasted ∼90 min. In addition, abundant Simplicispira candidate for PD was detected in biofilm. This study also suggests that regularly harvesting PD-related functional bacteria from a side-stream incubator promotes mainstream Anammox upgrade.}, } @article {pmid34998779, year = {2022}, author = {Dong, Y and Feng, D and Song, GL and Su, P and Zheng, D}, title = {The effect of a biofilm-forming bacterium Tenacibaculum mesophilum D-6 on the passive film of stainless steel in the marine environment.}, journal = {The Science of the total environment}, volume = {815}, number = {}, pages = {152909}, doi = {10.1016/j.scitotenv.2021.152909}, pmid = {34998779}, issn = {1879-1026}, mesh = {Biofilms ; Corrosion ; *Stainless Steel ; Surface Properties ; *Tenacibaculum ; }, abstract = {The microbiologically influenced corrosion of 304 stainless steel in the presence of a marine biofilm-forming bacterium Tenacibaculum mesophilum D-6 was systematically investigated by means of electrochemical techniques and surface analyses to reveal the effect of the selective attachment and adsorption of the biofilms on the passivity breakdown of the stainless steel. It was found that the T. mesophilum D-6 was electroactive and could oxidize low valent cations and metal, facilitating the local dissolution of the passive film and the substrate in the film defects, nearly doubling the surface roughness. The biofilms of T. mesophilum D-6 with mucopolysaccharide secreta and chloride ions tended to preferentially adsorb at the defects of the passive film on the steel, yielding non-homogeneous microbial aggregates and local Cl[-] enrichment there. The adsorption of the bacteria and chloride ions reduced the thickness of passive film by 23.9%, and generate more active sites for pitting corrosion on the passive film and more semiconducting carrier acceptors in the film. The maximum current density of the 304 SS in the presence of T. mesophilum D-6 was over one order of magnitude higher than that in the sterile medium, and the largest pit was deepened 3 times.}, } @article {pmid34998071, year = {2022}, author = {Desmond, P and Huisman, KT and Sanawar, H and Farhat, NM and Traber, J and Fridjonsson, EO and Johns, ML and Flemming, HC and Picioreanu, C and Vrouwenvelder, JS}, title = {Controlling the hydraulic resistance of membrane biofilms by engineering biofilm physical structure.}, journal = {Water research}, volume = {210}, number = {}, pages = {118031}, doi = {10.1016/j.watres.2021.118031}, pmid = {34998071}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Membranes, Artificial ; Ultrafiltration ; *Water Purification ; }, abstract = {The application of membrane technology for water treatment and reuse is hampered by the development of a microbial biofilm. Biofilm growth in micro-and ultrafiltration (MF/UF) membrane modules, on both the membrane surface and feed spacer, can form a secondary membrane and exert resistance to permeation and crossflow, increasing energy demand and decreasing permeate quantity and quality. In recent years, exhaustive efforts were made to understand the chemical, structural and hydraulic characteristics of membrane biofilms. In this review, we critically assess which specific structural features of membrane biofilms exert resistance to forced water passage in MF/UF membranes systems applied to water and wastewater treatment, and how biofilm physical structure can be engineered by process operation to impose less hydraulic resistance ("below-the-pain threshold"). Counter-intuitively, biofilms with greater thickness do not always cause a higher hydraulic resistance than thinner biofilms. Dense biofilms, however, had consistently higher hydraulic resistances compared to less dense biofilms. The mechanism by which density exerts hydraulic resistance is reported in the literature to be dependant on the biofilms' internal packing structure and EPS chemical composition (e.g., porosity, polymer concentration). Current reports of internal porosity in membrane biofilms are not supported by adequate experimental evidence or by a reliable methodology, limiting a unified understanding of biofilm internal structure. Identifying the dependency of hydraulic resistance on biofilm density invites efforts to control the hydraulic resistance of membrane biofilms by engineering internal biofilm structure. Regulation of biofilm internal structure is possible by alteration of key determinants such as feed water nutrient composition/concentration, hydraulic shear stress and resistance and can engineer biofilm structural development to decrease density and therein hydraulic resistance. Future efforts should seek to determine the extent to which the concept of "biofilm engineering" can be extended to other biofilm parameters such as mechanical stability and the implication for biofilm control/removal in engineered water systems (e.g., pipelines and/or, cooling towers) susceptible to biofouling.}, } @article {pmid34997847, year = {2022}, author = {Unsal, T and Wang, D and Kijkla, P and Kumseranee, S and Punpruk, S and Mohamed, ME and Saleh, MA and Gu, T}, title = {Food-grade D-limonene enhanced a green biocide in the mitigation of carbon steel biocorrosion by a mixed-culture biofilm consortium.}, journal = {Bioprocess and biosystems engineering}, volume = {45}, number = {4}, pages = {669-678}, pmid = {34997847}, issn = {1615-7605}, support = {MIC-JIP//Saudi Aramco/ ; MIC-JIP//PTTEP/ ; }, mesh = {Biofilms ; Carbon/pharmacology ; *Disinfectants/pharmacology ; Limonene/pharmacology ; *Steel/pharmacology ; }, abstract = {Microbiologically influenced corrosion (MIC), or microbial biocorrosion, is caused directly by microbial metabolic activities/products or induced by microbial biofilm's damage of a protective film that exposes a solid surface to a pre-existing corrosive environment. MIC causes billions of dollars of losses in various industrial processes, especially in oil and gas and water utilities. The mitigation of problematic industrial microbes typically relies on biocides whose discharges can cause environmental problems. Thus, more effective biocide applications are desired to minimize environmental impact. D-Limonene, a citrus peel oil, generally regarded as safe (GRAS), was used to enhance the popular biodegradable tetrakis hydroxymethyl phosphonium sulfate (THPS) biocide. An oilfield mixed-culture biofilm was grown anaerobically in enriched artificial seawater containing C1018 carbon steel coupons for 7 days at 37 °C. One hundred ppm (w/w) D-limonene reduced general heterotrophic bacteria (GHB) and acid-producing bacteria (APB) effectively, leading to 5.4-log and 6.0-log reductions in sessile GHB and APB cell counts, respectively, compared to no treatment control. The combination of 100 ppm D-limonene + 100 ppm THPS achieved extra 1.0-log SRB, 0.6-log GHB and 0.5-log APB reductions in sessile cell counts, which led to extra 58% reduction in microbial corrosion mass loss (1.2 vs. 0.5 mg/cm[2]) and extra 30% reductions in maximum pit depth (11.5 vs. 8.1 µm), compared to 100 ppm THPS-only treatment. Linear polarization resistance and potentiodynamic polarization (PDP) corrosion data supported mass loss and pitting data. Mixed-culture biofilms on carbon steel coupons after 7 day incubation at 37 °C showing enhanced biocide treatment outcome using D-limonene + THPS: A no treatment, B 100 ppm D-limonene, C 100 ppm THPS, D 100 ppm D-limonene + 100 ppm THPS.}, } @article {pmid34997845, year = {2022}, author = {Pang, Y and Wang, S and Tao, J and Wang, J and Xue, Z and Wang, R}, title = {Mechanism of berberine hydrochloride interfering with biofilm formation of Hafnia alvei.}, journal = {Archives of microbiology}, volume = {204}, number = {2}, pages = {126}, pmid = {34997845}, issn = {1432-072X}, support = {2018YFC1704506//National Key Clinical Specialty Discipline Construction Program of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Berberine/pharmacology ; Biofilms ; *Hafnia alvei ; Molecular Docking Simulation ; Quorum Sensing ; }, abstract = {The mechanism of berberine hydrochloride (BBH) inhibiting the biofilm formation of Hafnia alvei was investigated in this study. The antibiofilm potential of BBH was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) as well as crystal violet staining. The quorum-sensing (QS) inhibition was revealed by determination of QS-related genes expression and related signal molecules production using real-time quantitative PCR (RT-qPCR) and high performance liquid chromatography (HPLC). The binding of BBH to receptor proteins was simulated by molecular docking and molecular dynamics simulations. It was found that BBH at sub-minimum inhibitory concentrations (sub-MICs) significantly reduced the biofilm formation of H. alvei in a dose dependent manner. BBH inhibited the bacterial swimming motility, decreased the transcription of halI and halR genes, and reduced the production of signal molecule C14-HSL. It bound to HalR protein mainly through Van der Waals force and electrostatic interaction force. Based on these results, it was concluded that BBH inhibits the biofilm formation of H. alvei and the mechanism is related to its interference with QS through down-regulating the expression of halI and halR genes.}, } @article {pmid34997073, year = {2022}, author = {Mangalea, MR and Borlee, BR}, title = {The NarX-NarL two-component system regulates biofilm formation, natural product biosynthesis, and host-associated survival in Burkholderia pseudomallei.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {203}, pmid = {34997073}, issn = {2045-2322}, support = {1450032//National Science Foundation/ ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Benzopyrans/metabolism ; Biofilms/*growth & development ; Biological Products/*metabolism ; Burkholderia pseudomallei/genetics/growth & development/*metabolism ; Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions ; Lactones/metabolism ; Microbial Viability ; Mutation ; Nitrates/*metabolism ; Nitrites/*metabolism ; Transcription, Genetic ; }, abstract = {Burkholderia pseudomallei is a saprophytic bacterium endemic throughout the tropics causing severe disease in humans and animals. Environmental signals such as the accumulation of inorganic ions mediates the biofilm forming capabilities and survival of B. pseudomallei. We have previously shown that B. pseudomallei responds to nitrate and nitrite by inhibiting biofilm formation and altering cyclic di-GMP signaling. To better understand the roles of nitrate-sensing in the biofilm inhibitory phenotype of B. pseudomallei, we created in-frame deletions of narX (Bp1026b_I1014) and narL (Bp1026b_I1013), which are adjacent components of a conserved nitrate-sensing two-component system. We observed transcriptional downregulation in key components of the biofilm matrix in response to nitrate and nitrite. Some of the most differentially expressed genes were nonribosomal peptide synthases (NRPS) and/or polyketide synthases (PKS) encoding the proteins for the biosynthesis of bactobolin, malleilactone, and syrbactin, and an uncharacterized cryptic NRPS biosynthetic cluster. RNA expression patterns were reversed in ∆narX and ∆narL mutants, suggesting that nitrate sensing is an important checkpoint for regulating the diverse metabolic changes occurring in the biofilm inhibitory phenotype. Moreover, in a macrophage model of infection, ∆narX and ∆narL mutants were attenuated in intracellular replication, suggesting that nitrate sensing contributes to survival in the host.}, } @article {pmid34997051, year = {2022}, author = {Chandrasekharan, S and Chinnasamy, G and Bhatnagar, S}, title = {Sustainable phyto-fabrication of silver nanoparticles using Gmelina arborea exhibit antimicrobial and biofilm inhibition activity.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {156}, pmid = {34997051}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology/toxicity ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Cell Line ; Cell Movement/drug effects ; Cell Proliferation/drug effects ; Disk Diffusion Antimicrobial Tests ; Fibroblasts/drug effects/pathology ; *Green Chemistry Technology ; Humans ; *Lamiaceae ; Microbial Viability/drug effects ; Plant Extracts/*chemistry ; Silver Compounds/chemistry/*pharmacology/toxicity ; }, abstract = {Increase in bacterial resistance to commonly used antibiotics is a major public health concern generating interest in novel antibacterial treatments. Aim of this scientific endeavor was to find an alternative efficient antibacterial agent from non-conventional plant source for human health applications. We used an eco-friendly approach for phyto-fabrication of silver nanoparticles (AgNPs) by utilizing logging residue from timber trees Gmelina arborea (GA). GC-MS analysis of leaves, barks, flowers, fruits, and roots was conducted to determine the bioactive compounds. Biosynthesis, morphological and structural characterization of GA-AgNPs were undertaken by UV-Vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). GA-AgNPs were evaluated for antibacterial, antibiofilm, antioxidant, wound healing properties and their toxicity studies were carried out. Results identified the presence of terpenoids, sterols, aliphatic alcohols, aldehydes, and flavonoids in leaves, making leaf extract the ideal choice for phyto-fabrication of silver nanoparticles. The synthesis of GA-AgNPs was confirmed by dark brown colored colloidal solution and spectral absorption peak at 420 nm. Spherical, uniformly dispersed, crystalline GA-AgNPs were 34-40 nm in diameter and stable in solutions at room temperature. Functional groups attributed to the presence of flavonoids, terpenoids, and phenols that acted as reducing and capping agents. Antibacterial potency was confirmed against pathogenic bacteria Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus by disc diffusion assay, MIC and MBC assay, biofilm inhibition assay, electron-microscopy, cell staining and colony counting techniques. The results from zone of inhibition, number of ruptured cells and dead-cell-count analysis confirmed that GA-AgNPs were more effective than GA-extract and their bacteria inhibition activity level increased further when loaded on hydrogel as GA-AgNPs-PF127, making it a novel distinguishing feature. Antioxidant activity was confirmed by the free radical scavenging assays (DPPH and ABTS). Wound healing potential was confirmed by cell scratch assay in human dermal fibroblast cell lines. Cell-proliferation study in human chang liver cell lines and optical microscopic observations confirmed non-toxicity of GA-AgNPs at low doses. Our study concluded that biosynthesized GA-AgNPs had enhanced antibacterial, antibiofilm, antioxidant, and wound healing properties.}, } @article {pmid34996996, year = {2022}, author = {Elekhnawy, E and Negm, WA and El-Aasr, M and Kamer, AA and Alqarni, M and Batiha, GE and Obaidullah, AJ and Fawzy, HM}, title = {Histological assessment, anti-quorum sensing, and anti-biofilm activities of Dioon spinulosum extract: in vitro and in vivo approach.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {180}, pmid = {34996996}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Chromobacterium/*drug effects/growth & development/metabolism ; Disease Models, Animal ; Female ; Gene Expression Regulation, Bacterial ; Indoles/metabolism ; Microbial Sensitivity Tests ; Plant Extracts/isolation & purification/*pharmacology ; Pseudomonas Infections/microbiology/pathology/*prevention & control ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development/metabolism ; Quorum Sensing/*drug effects ; Rats ; Skin Diseases, Bacterial/microbiology/pathology/*prevention & control ; *Zamiaceae/chemistry ; }, abstract = {Pseudomonas aeruginosa is an opportunistic bacterium causing several health problems and having many virulence factors like biofilm formation on different surfaces. There is a significant need to develop new antimicrobials due to the spreading resistance to the commonly used antibiotics, partly attributed to biofilm formation. Consequently, this study aimed to investigate the anti-biofilm and anti-quorum sensing activities of Dioon spinulosum, Dyer Ex Eichler extract (DSE), against Pseudomonas aeruginosa clinical isolates. DSE exhibited a reduction in the biofilm formation by P. aeruginosa isolates both in vitro and in vivo rat models. It also resulted in a decrease in cell surface hydrophobicity and exopolysaccharide quantity of P. aeruginosa isolates. Both bright field and scanning electron microscopes provided evidence for the inhibiting ability of DSE on biofilm formation. Moreover, it reduced violacein production by Chromobacterium violaceum (ATCC 12,472). It decreased the relative expression of 4 quorum sensing genes (lasI, lasR, rhlI, rhlR) and the biofilm gene (ndvB) using qRT-PCR. Furthermore, DSE presented a cytotoxic activity with IC50 of 4.36 ± 0.52 µg/ml against human skin fibroblast cell lines. For the first time, this study reports that DSE is a promising resource of anti-biofilm and anti-quorum sensing agents.}, } @article {pmid34995513, year = {2022}, author = {Chou, KT and Lee, DD and Chiou, JG and Galera-Laporta, L and Ly, S and Garcia-Ojalvo, J and Süel, GM}, title = {A segmentation clock patterns cellular differentiation in a bacterial biofilm.}, journal = {Cell}, volume = {185}, number = {1}, pages = {145-157.e13}, pmid = {34995513}, issn = {1097-4172}, support = {R01 GM121888/GM/NIGMS NIH HHS/United States ; R35 GM139645/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacillus subtilis/*genetics/*growth & development/metabolism ; Biofilms/*growth & development ; Body Patterning/*genetics ; Gene Expression ; Gene Expression Regulation, Developmental ; Kinetics ; Models, Biological ; Nitrogen/metabolism ; Signal Transduction/genetics ; Somites/growth & development ; Spores, Bacterial/growth & development ; Stress, Physiological/genetics ; Time Factors ; }, abstract = {Contrary to multicellular organisms that display segmentation during development, communities of unicellular organisms are believed to be devoid of such sophisticated patterning. Unexpectedly, we find that the gene expression underlying the nitrogen stress response of a developing Bacillus subtilis biofilm becomes organized into a ring-like pattern. Mathematical modeling and genetic probing of the underlying circuit indicate that this patterning is generated by a clock and wavefront mechanism, similar to that driving vertebrate somitogenesis. We experimentally validated this hypothesis by showing that predicted nutrient conditions can even lead to multiple concentric rings, resembling segments. We additionally confirmed that this patterning mechanism is driven by cell-autonomous oscillations. Importantly, we show that the clock and wavefront process also spatially patterns sporulation within the biofilm. Together, these findings reveal a biofilm segmentation clock that organizes cellular differentiation in space and time, thereby challenging the paradigm that such patterning mechanisms are exclusive to plant and animal development.}, } @article {pmid34991317, year = {2022}, author = {Wang, H and Yu, P and Schwarz, C and Zhang, B and Huo, L and Shi, B and Alvarez, PJJ}, title = {Phthalate Esters Released from Plastics Promote Biofilm Formation and Chlorine Resistance.}, journal = {Environmental science & technology}, volume = {56}, number = {2}, pages = {1081-1090}, doi = {10.1021/acs.est.1c04857}, pmid = {34991317}, issn = {1520-5851}, mesh = {Biofilms ; China ; Chlorine/pharmacology ; Dibutyl Phthalate ; *Diethylhexyl Phthalate ; Esters ; *Phthalic Acids/pharmacology ; Plastics ; }, abstract = {Phthalate esters (PAEs) are commonly released from plastic pipes in some water distribution systems. Here, we show that exposure to a low concentration (1-10 μg/L) of three PAEs (dimethyl phthalate (DMP), di-n-hexyl phthalate (DnHP), and di-(2-ethylhexyl) phthalate (DEHP)) promotes Pseudomonas biofilm formation and resistance to free chlorine. At PAE concentrations ranging from 1 to 5 μg/L, genes coding for quorum sensing, extracellular polymeric substances excretion, and oxidative stress resistance were upregulated by 2.7- to 16.8-fold, 2.1- to 18.9-fold, and 1.6- to 9.9-fold, respectively. Accordingly, more biofilm matrix was produced and the polysaccharide and eDNA contents increased by 30.3-82.3 and 10.3-39.3%, respectively, relative to the unexposed controls. Confocal laser scanning microscopy showed that PAE exposure stimulated biofilm densification (volumetric fraction increased from 27.1 to 38.0-50.6%), which would hinder disinfectant diffusion. Biofilm densification was verified by atomic force microscopy, which measured an increase of elastic modulus by 2.0- to 3.2-fold. PAE exposure also stimulated the antioxidative system, with cell-normalized superoxide dismutase, catalase, and glutathione activities increasing by 1.8- to 3.0-fold, 1.0- to 2.0-fold, and 1.2- to 1.6-fold, respectively. This likely protected cells against oxidative damage by chlorine. Overall, we demonstrate that biofilm exposure to environmentally relevant levels of PAEs can upregulate molecular processes and physiologic changes that promote biofilm densification and antioxidative system expression, which enhance biofilm resistance to disinfectants.}, } @article {pmid34991045, year = {2022}, author = {Caliani, I and De Marco, G and Cappello, T and Giannetto, A and Mancini, G and Ancora, S and Maisano, M and Parrino, V and Cappello, S and Bianchi, N and Oliva, S and Luciano, A and Mauceri, A and Leonzio, C and Fasulo, S}, title = {Assessment of the effectiveness of a novel BioFilm-Membrane BioReactor oil-polluted wastewater treatment technology by applying biomarkers in the mussel Mytilus galloprovincialis.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {243}, number = {}, pages = {106059}, doi = {10.1016/j.aquatox.2021.106059}, pmid = {34991045}, issn = {1879-1514}, mesh = {Animals ; Biofilms ; Biomarkers ; Bioreactors ; *Mytilus ; Wastewater/analysis ; *Water Pollutants, Chemical/toxicity ; *Water Purification ; }, abstract = {Petrochemical industries and oil refineries are sources of hazardous chemicals into the aquatic environments, and often a leading cause of reduced oxygen availability, thus resulting in adverse effects in biota. This study is an expansion of our previous work on the assessment of the BioFilm-Membrane Bioreactor (BF-MBR) to mitigate the impact of oil-polluted wastewater on marine environments. Specifically, this study evaluated the reduction of selected chemical constituents (hydrocarbons and trace metals) and toxicity related to hypoxia and DNA damage to mussels Mytilus galloprovincialis, before and after treatment of oil-polluted wastewater with the BF-MBR. The application of a multidisciplinary approach provided evidence of the efficiency of BF-MBR to significantly reducing the pollutants load from oily contaminated seawaters. As result, the health status of mussels was preserved by a hypoxic condition due to oily pollutants, as evidenced by the modulation in the gene expression of HIF-1α and PHD and changes in the level of hypotaurine and taurine. Moreover, ameliorative effects in the energy metabolism were also found in mussel gills showing increased levels of glycogen, glucose and ATP, as well as a mitigated genotoxicity was revealed by the Micronucleus and Comet assays. Overall, findings from this study support the use of the BF-MBR as a promising treatment biotechnology to avoid or limiting the compromise of marine environments from oil pollution.}, } @article {pmid34990042, year = {2022}, author = {Conwell, M and Dooley, JSG and Naughton, PJ}, title = {Enterococcal biofilm-A nidus for antibiotic resistance transfer?.}, journal = {Journal of applied microbiology}, volume = {132}, number = {5}, pages = {3444-3460}, pmid = {34990042}, issn = {1365-2672}, support = {//Department for the Economy/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Drug Resistance, Multiple, Bacterial/genetics ; *Enterococcus/genetics ; Gene Transfer, Horizontal ; }, abstract = {Enterococci, which are on the WHO list of priority pathogens, are commonly encountered in hospital acquired infection and are becoming increasing significant due to the development of strains resistant to multiple antibiotics. Enterococci are also important microorganisms in the environment, and their presence is frequently used as an indicator of faecal pollution. Their success is related to their ability to survive within a broad range of habitats and the ease by which they acquire mobile genetic elements, including plasmids, from other bacteria. The enterococci are frequently present within a bacterial biofilm, which provides stability and protection to the bacterial population along with an opportunity for a variety of bacterial interactions. Enterococci can accept extrachromosomal DNA both from within its own species and from other bacterial species, and this is enhanced by the proximity of the donor and recipient strains. It is this exchange of genetic material that makes the role of biofilms such an important aspect of the success of enterococci. There remain many questions regarding the most suitable model systems to study enterococci in biofilms and regarding the transfer of genetic material including antibiotic resistance in these biofilms. This review focuses on some important aspects of biofilm in the context of horizontal gene transfer (HGT) in enterococci.}, } @article {pmid34990013, year = {2022}, author = {Gindl, A and Schötta, AM and Berent, S and Markowicz, M and Stockinger, H and Thalhammer, F and Stary, G and Strobl, J}, title = {Persistent Lyme disease with cutaneous Borrelia biofilm formation.}, journal = {The British journal of dermatology}, volume = {186}, number = {6}, pages = {1041-1043}, pmid = {34990013}, issn = {1365-2133}, mesh = {Administration, Cutaneous ; Biofilms ; *Borrelia ; *Borrelia burgdorferi ; Humans ; *Lyme Disease/diagnosis ; Skin ; }, } @article {pmid34989883, year = {2022}, author = {Tsukatani, T and Kuroda, R and Kawaguchi, T}, title = {Screening biofilm eradication activity of ethanol extracts from foodstuffs: potent biofilm eradication activity of glabridin, a major flavonoid from licorice (Glycyrrhiza glabra), alone and in combination with ɛ-poly-L-lysine.}, journal = {World journal of microbiology & biotechnology}, volume = {38}, number = {2}, pages = {24}, pmid = {34989883}, issn = {1573-0972}, support = {JP25450123//japan society for the promotion of science/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Ethanol ; Flavonoids/*pharmacology ; Food Additives ; Glycyrrhiza/*chemistry ; Isoflavones/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Phenols/*pharmacology ; Plant Extracts/*pharmacology ; Polylysine/*pharmacology ; Porphyromonas gingivalis/drug effects ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; Streptococcus mutans/drug effects ; }, abstract = {The ethanol extracts of 155 different foodstuffs containing medicinal plants were investigated for their biofilm eradication activities against pathogenic bacteria. A combined method of a colorimetric microbial viability assay based on reduction of a tetrazolium salt (WST-8) and a biofilm formation technique on the 96-pins of a microtiter plate lid was used to screen the biofilm eradication activities of foodstuffs. The ethanol extracts of licorice (Glycyrrhiza glabra) showed potent biofilm eradication activities against Streptococcus mutans, Staphylococcus aureus, and Porphyromonas gingivalis. Among the antimicrobial constituents in licorice, glabridin had the most potent eradication activities against microbial biofilms. The minimum biofilm eradication concentration of glabridin was 25-50 μg/ml. Furthermore, the combination of glabridin with ɛ-poly-L-lysine, a food additive, could result in broad biofilm eradication activities towards a wide variety of bacteria associated with infection, including Escherichia coli and Pseudomonas aeruginosa.}, } @article {pmid34989676, year = {2022}, author = {de Vor, L and van Dijk, B and van Kessel, K and Kavanaugh, JS and de Haas, C and Aerts, PC and Viveen, MC and Boel, EC and Fluit, AC and Kwiecinski, JM and Krijger, GC and Ramakers, RM and Beekman, FJ and Dadachova, E and Lam, MG and Vogely, HC and van der Wal, BC and van Strijp, JA and Horswill, AR and Weinans, H and Rooijakkers, SH}, title = {Human monoclonal antibodies against Staphylococcus aureus surface antigens recognize in vitro and in vivo biofilm.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {34989676}, issn = {2050-084X}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; I01 BX002711/BX/BLRD VA/United States ; }, mesh = {Animals ; Antibodies, Monoclonal/*immunology/*metabolism ; *Biofilms ; Catheter-Related Infections/immunology/microbiology/therapy ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*immunology ; Teichoic Acids/immunology/metabolism ; }, abstract = {Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and potential treatment of biofilm-related infections. Here, we show that mAbs targeting common surface components of S. aureus can recognize clinically relevant biofilm types. The mAbs were also shown to bind a collection of clinical isolates derived from different biofilm-associated infections (endocarditis, prosthetic joint, catheter). We identify two groups of antibodies: one group that uniquely binds S. aureus in biofilm state and one that recognizes S. aureus in both biofilm and planktonic state. Furthermore, we show that a mAb recognizing wall teichoic acid (clone 4497) specifically localizes to a subcutaneously implanted pre-colonized catheter in mice. In conclusion, we demonstrate the capacity of several human mAbs to detect S. aureus biofilms in vitro and in vivo.}, } @article {pmid34989526, year = {2022}, author = {Wu, S and Wang, SY and Wang, F and Ji, M}, title = {[Effect of Temperature on ANAMMOX Process in Sequencing Batch Biofilm Reactors: Nitrogen Removal Performance and Bacterial Community].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {43}, number = {1}, pages = {416-423}, doi = {10.13227/j.hjkx.202105280}, pmid = {34989526}, issn = {0250-3301}, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Temperature ; }, abstract = {For the ambient and low-temperature operation of the anaerobic ammonium oxidation (ANAMMOX) process, sequence batch biofilm reactors (SBBR) with non-woven fabric and modified polyurethane foam as carriers, respectively, were used to treat nitrogenous wastewater. Nitrogen removal performances of both reactors were investigated while the temperature decreased from 35℃ to 15℃. When the nitrogen loading rate (NLR) was 110 mg·(L·d)[-1], the average total nitrogen (TN) removal rate of the non-woven fabric reactor increased from 71.16% (35℃) to 76.19% (30℃) and then decreased to 61.11% (15℃). The average TN removal rate of the modified polyurethane foam reactor increased from 78.71% (35℃) to 81.75% (20℃) and then decreased to 75.68% (15℃). Compared with the non-woven fabric, the modified polyurethane foam provided a more stable nitrogen removal performance and could be used as the preferred carrier. High-throughput sequencing of the modified polyurethane foam biofilm indicated that Candidatus Kuenenia was the dominant ANAMMOX genus, with relative abundances of 8% (35℃), 5% (25℃), and 16% (15℃). Candidatus Kuenenia still grew and enriched at low temperatures. The decrease in temperature significantly affected the biofilm microbial community structure.}, } @article {pmid34989525, year = {2022}, author = {Deng, CL and Guo, L and Wang, XJ and Chen, ZG}, title = {[Nitritation Performance of Zeolite Moving Bed Biofilm Reactor for Ammonium Wastewater Treatment].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {43}, number = {1}, pages = {409-415}, doi = {10.13227/j.hjkx.202104151}, pmid = {34989525}, issn = {0250-3301}, mesh = {Ammonia ; *Ammonium Compounds ; Biofilms ; Bioreactors ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater ; *Water Purification ; *Zeolites ; }, abstract = {A new type of zeolite-suspended packing was developed by using zeolite as an important raw material, which was then used to start the zeolite moving bed biofilm reactor (ZMBBR). ZMBBR was compared with the ceramsite moving bed biofilm reactor (CMBBR) packed with ordinary ceramsite-suspended packing to investigate the different nitritation performance. The results showed that stable nitritation was successfully achieved in two reactors by the inhibitory effect of free ammonia (FA), and both of their nitrite accumulation rates (NAR) reached 90%; due to the adsorption of zeolite to ammonium, ZMBBR relieved the inhibition of FA on AOB faster than CMBBR and achieved nitritation earlier; CMBBR and ZMBBR could maintain long-term stable nitrosation when ρ(NH4[+]-N) was 350 mg·L[-1] and 1050 mg·L[-1] and NPRAVG was 0.43 kg·(m[3]·d)[-1] and 1.26 kg·(m[3]·d)[-1], respectively, and ARECMBBR=82.21% and AREZMBBR=88.85%. In the process of the influent ρ(NH4[+]-N) gradually increasing from 250 mg·L[-1] to 1250 mg·L[-1], the maximum nitrite production rate (NPR) of CMBBR was 0.5634 kg·(m[3]·d)[-1]; when ρ(FA) reached 166 mg·L[-1] at the influent ρ(NH4[+]-N) of 750 mg·L[-1], CMBBR broke down for the heavy inhibition of FA. The maximum NPR of ZMBBR was 1.800 kg·(m[3]·d)[-1], and the performance of ZMBBR was getting worse after the ρ(FNA) reached the peak value of 1.9611 mg·L[-1] at the influent ρ(NH4[+]-N) of 1250 mg·L[-1]. Subsequently, the ρ(FA) of ZMBBR reached 158 mg·L[-1] rapidly, the NPR dropped significantly to 0.9028 kg·(m[3]·d)[-1], and the performance of ZMBBR became significantly worse. It was demonstrated by high-throughput sequencing analysis that the dominant strain of ZMBBR and CMBBR was Nitrosomonas_europaea, and the relative abundances of N._europaea in ZMBBR and CMBBR were 11.15% and 10.92%, respectively.}, } @article {pmid34989513, year = {2022}, author = {Xu, JL and Xu, Y and Li, XM and Guo, M and Liu, CH}, title = {[Persistent Inhibition of Ammonium Released from Contaminated Sediments Through a Modified Zeolite and Biofilm System Enhanced by Signaling Molecules].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {43}, number = {1}, pages = {285-294}, doi = {10.13227/j.hjkx.202105046}, pmid = {34989513}, issn = {0250-3301}, mesh = {*Ammonium Compounds ; Biofilms ; Geologic Sediments ; *Water Pollutants, Chemical/analysis ; *Zeolites ; }, abstract = {This experiment used a modified zeolite and biofilm system to find a long-term effective way of repairing sediment. Four types of modified zeolites[AlCl3, Al(NO3)3, Al2(SO4)3, and KAl(SO4)2] and a biofilm system were investigated for the removal of ammonia nitrogen from overlaying water. The results showed that, of the modified zeolites, AlCl3 had the greatest effect on the zeolite and biofilm system, and the optimal modified concentration was 0.8 mol·L[-1]. The persistence was further studied after adding OHHL, including the inhibition of ammonium released from contaminated sediment by the AlCl3-modified zeolite and biofilm system, NaCl-modified zeolite and biofilm system, and natural zeolite and biofilm system. The results illuminated that the number of bacteria attached to the AlCl3-modified zeolite and biofilm system was the highest, and the proportion of denitrifying bacteria was also high (the initial proportion was 82.1%; 30 days later it was 61.1%). Therefore, the biological regeneration was high (64.9%), which caused the zeolite service life to be up to 8.5 months. Thus, ammonium released from contaminated sediment can be inhibited effectively and continuously by an AlCl3-modified zeolite and biofilm system.}, } @article {pmid34989129, year = {2022}, author = {Piri-Gharaghie, T and Beiranvand, S and Riahi, A and Shirin, NJ and Badmasti, F and Mirzaie, A and Elahianfar, Y and Ghahari, S and Ghahari, S and Pasban, K and Hajrasouliha, S}, title = {Fabrication and Characterization of Thymol-Loaded Chitosan Nanogels: Improved Antibacterial and Anti-Biofilm Activities with Negligible Cytotoxicity.}, journal = {Chemistry & biodiversity}, volume = {19}, number = {3}, pages = {e202100426}, doi = {10.1002/cbdv.202100426}, pmid = {34989129}, issn = {1612-1880}, support = {//Biotechnology Research Center/ ; //Islamic Azad University/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms ; *Chitosan/chemistry/pharmacology ; HEK293 Cells ; Humans ; Microbial Sensitivity Tests ; Nanogels ; *Thymol/chemistry/pharmacology ; }, abstract = {Thymol is a monoterpene phenolic derivative extracted from the Thymus vulgaris which has antimicrobial effects. In the present study, thymol-loaded chitosan nanogels were prepared and their physicochemical properties were characterized. The encapsulation efficiency of thymol into chitosan and its stability were determined. The in vitro antimicrobial and anti-biofilm activities of thymol-loaded chitosan nanogel (Ty-CsNG), free thymol (Ty), and free chitosan nanogel (CsNG) were evaluated against both Gram-negative and Gram-positive multidrug-resistant (MDR) bacteria including Staphylococcus aureus, Acinetobacter baumanii, and Pseudomonas aeruginosa strains using the broth microdilution and crystal violet assay, respectively. After treatment of MDR strains with sub-minimum inhibitory concentration (Sub-MIC) of Ty-CsNG, free Ty and CsNG, biofilm gene expression analysis was studied. Moreover, cytotoxicity of Ty-CsNG, free Ty, and CsNG against HEK-293 normal cell line was determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. The average size of Ty-CsNG was 82.71±9.6 nm, encapsulation efficiency was 76.54±0.62 % with stability up to 60 days at 4 °C. Antibacterial activity test revealed that Ty-CsNG reduced the MIC by 4-6 times in comparison to free thymol. In addition, the expression of biofilm-related genes including ompA, and pgaB were significantly down-regulated after treatment of strains with Ty-CsNG (P<0.05). In addition, free CsNG displayed negligible cytotoxicity against HEK-293 normal cell lines and presented a biocompatible nanoscale delivery system. Based on the results, it can be concluded that Ty-CsNG can be considered a promising candidate for enhancing antimicrobial and anti-biofilm activities.}, } @article {pmid34989075, year = {2022}, author = {Chaudhary, N and Mohan, B and Mavuduru, RS and Kumar, Y and Taneja, N}, title = {Characterization, genome analysis and in vitro activity of a novel phage vB_EcoA_RDN8.1 active against multi-drug resistant and extensively drug-resistant biofilm-forming uropathogenic Escherichia coli isolates, India.}, journal = {Journal of applied microbiology}, volume = {132}, number = {4}, pages = {3387-3404}, doi = {10.1111/jam.15439}, pmid = {34989075}, issn = {1365-2672}, support = {313690//University Grants Commission/ ; 102/IFD/SAN/2138/2019-2020//Department of Biotechnology , Ministry of Science and Technology/ ; }, mesh = {*Bacteriophages/genetics ; Biofilms ; Humans ; Myoviridae ; *Urinary Tract Infections ; *Uropathogenic Escherichia coli/genetics ; }, abstract = {AIM: We aimed to study host range, stability, genome and antibiofilm activity of a novel phage vB_EcoA_RDN8.1 active against multi-drug resistant (MDR) and extensively drug-resistant (XDR) biofilm-forming uropathogenic Escherichia coli isolates.

METHODS AND RESULTS: A novel lytic phage vB_EcoA_RDN8.1 active against UPEC strains resistant to third-generation cephalosporins, fluoroquinolones, aminoglycosides, imipenem, beta-lactamase inhibitor combination and polymyxins was isolated from community raw sewage water of Chandigarh. It exhibited a clear plaque morphology and a burst size of 250. In the time-kill assay, the maximum amount of killing was achieved at MOI 1.0. vB_EcoA_RDN8.1 belongs to the family Autographiviridae, has a genome size of 39.5 kb with a GC content of 51.6%. It was stable over a wide range of temperatures and pH. It was able to inhibit biofilm formation which may be related to an endolysin encoded by ORF 19.

CONCLUSIONS: The vB_EcoA_RDN8.1 is a novel lytic phage that has the potential for inclusion into phage cocktails being developed for the treatment of urinary tract infections (UTIs) caused by highly drug-resistant UPEC.

We provide a detailed characterization of a novel lytic Escherichia phage with antibiofilm activity having a potential application against MDR and XDR UPEC causing UTIs.}, } @article {pmid34988694, year = {2022}, author = {Kamionka, J and Matthes, R and Holtfreter, B and Pink, C and Schlüter, R and von Woedtke, T and Kocher, T and Jablonowski, L}, title = {Efficiency of cold atmospheric plasma, cleaning powders and their combination for biofilm removal on two different titanium implant surfaces.}, journal = {Clinical oral investigations}, volume = {26}, number = {3}, pages = {3179-3187}, pmid = {34988694}, issn = {1436-3771}, mesh = {Biofilms ; *Dental Implants/microbiology ; Humans ; *Peri-Implantitis/microbiology ; *Plasma Gases ; Powders ; Surface Properties ; Titanium/chemistry ; }, abstract = {OBJECTIVES: Biofilm removal is the decisive factor for the control of peri-implantitis. Cold atmospheric pressure plasma (CAP) can become an effective aid due to its ability to destroy and to inactivate bacterial biofilm residues. This study evaluated the cleaning efficiency of CAP, and air-polishing with glycine (APG) or erythritol (APE) containing powders alone or in combination with CAP (APG + CAP, APE + CAP) on sandblasted/acid etched, and anodised titanium implant surface.

MATERIALS AND METHODS: On respective titanium discs, a 7-day ex vivo human biofilm was grown. Afterwards, the samples were treated with CAP, APG, APE, APG + CAP, and APE + CAP. Sterile and untreated biofilm discs were used for verification. Directly after treatment and after 5 days of incubation in medium at 37 °C, samples were prepared for examination by fluorescence microscopy. The relative biofilm fluorescence was measured for quantitative analyses.

RESULTS: Air-polishing with or without CAP removed biofilms effectively. The combination of air-polishing with CAP showed the best cleaning results compared to single treatments, even on day 5. Immediately after treatment, APE + CAP showed insignificant higher cleansing efficiency than APG + CAP.

CONCLUSIONS: CAP supports mechanical cleansing and disinfection to remove and inactivate microbial biofilm on implant surfaces significantly. Here, the type of the powder was not important. The highest cleansing results were obtained on sandblasted/etched surfaces.

CLINICAL RELEVANCE: Microbial residuals impede wound healing and re-osseointegration after peri-implantitis treatment. Air-polishing treatment removes biofilms very effectively, but not completely. In combination with CAP, microbial free surfaces can be achieved. The tested treatment regime offers an advantage during treatment of peri-implantitis.}, } @article {pmid34987914, year = {2021}, author = {Kumar, A and Seenivasan, MK and Inbarajan, A}, title = {A Literature Review on Biofilm Formation on Silicone and Poymethyl Methacrylate Used for Maxillofacial Prostheses.}, journal = {Cureus}, volume = {13}, number = {11}, pages = {e20029}, pmid = {34987914}, issn = {2168-8184}, abstract = {Silicone elastomers are considered the most suitable maxillofacial materials for extraoral prostheses to date due to their superior physicochemical properties. The aim of this review was to describe the characteristics of biofilm formation on silicone and polymethyl methacrylate used for maxillofacial prostheses and review different strategies of biofilm management for silicone maxillofacial prosthesis. A structured literature search was conducted using the following databases - PubMed, Google Scholar, ScienceDirect, LILACS, IndeMED, OVID, EMBASE, NIH Clinical Trials - for reports related to the biofilms. English language articles were only included in the study. Biofilms induced various systemic infections if they are not treated at an early stage. Biofilms are formed due to various reasons like fungal, bacterial and mixed infections of the patient and also due to prosthetic appliances. The manual or mechanical pressure physically removes the biofilm and most biofilm molecules from surfaces. Treatment must be given with utmost caution and concern irrespective of the presence or absence of biofilm. With regards to the materials used for fabricating maxillofacial substitutes, it has been defined that both acrylic resin and silicone may harbour microorganisms, however, the larger porosities in silicone make it vulnerable to microbial adhesion. The major limitations of these materials are that they have numerous porosities on their surface and, along with the modification of the anatomy of the facial tissues as a result of the lesion, may compromise the natural balance of the microbial flora, favouring microbial colonization and formation of biofilms.}, } @article {pmid34986390, year = {2022}, author = {Huang, C and Tao, S and Yuan, J and Li, X}, title = {Effect of sodium hypochlorite on biofilm of Klebsiella pneumoniae with different drug resistance.}, journal = {American journal of infection control}, volume = {50}, number = {8}, pages = {922-928}, doi = {10.1016/j.ajic.2021.12.003}, pmid = {34986390}, issn = {1527-3296}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance ; Humans ; *Klebsiella pneumoniae ; Microbial Sensitivity Tests ; *Sodium Hypochlorite/pharmacology ; }, abstract = {BACKGROUND: Biofilm formation is a major factor in the resistance mechanism of Klebsiella pneumoniae. This study aimed to evaluate the effects of sodium hypochlorite on the biofilm of K. pneumoniae with different drug resistance.

METHODS: We collected 3 different types of K. pneumoniae respectively. The growth trend of biofilms of different drug-resistant K. pneumoniae was quantified by measuring the OD590 for 7 consecutive days using crystal violet staining. Scanning confocal fluorescence microscopy was used to observe biofilm morphology.

RESULTS: After adding sodium hypochlorite, there were significant differences between the OD590 value of the 200, 500, and 1,000 µg/mL groups and the positive control group (all P < .05) on the fifth day. Concentrations of 2,000 and 5,000 µg/mL sodium hypochlorite were added after the biofilm had matured. In the 5,000 µg/mL sodium hypochlorite group, the OD590 of K. pneumoniae biofilm in the 3 groups decreased significantly compared with the blank control group (all P < .05).

CONCLUSIONS: Sodium hypochlorite inhibited and cleared the biofilm of K. pneumoniae with different drug resistance, and the effect was enhanced with the increase of concentration in the range of bacteriostatic and bactericidal concentration.}, } @article {pmid34986264, year = {2022}, author = {Narciso, DAC and Pereira, A and Dias, NO and Melo, LF and Martins, FG}, title = {Characterization of biofilm structure and properties via processing of 2D optical coherence tomography images in BISCAP.}, journal = {Bioinformatics (Oxford, England)}, volume = {38}, number = {6}, pages = {1708-1715}, doi = {10.1093/bioinformatics/btac002}, pmid = {34986264}, issn = {1367-4811}, support = {Base-UIDB/00511/2020//Funding of the Laboratory for Process Engineering, Environment, Biotechnology and Energy-LEPABE-funded by national funds through the FCT/MCTES (PIDDAC)/ ; }, mesh = {Humans ; *Tomography, Optical Coherence/methods ; *Image Processing, Computer-Assisted/methods ; Microscopy, Confocal/methods ; Software ; Biofilms ; }, abstract = {MOTIVATION: Processing of Optical Coherence Tomography (OCT) biofilm images is currently restricted to a set of custom-made MATLAB scripts. None of the tools currently available for biofilm image processing (including those developed for Confocal Laser Scanning Microscopy-CLSM) enable a fully automatic processing of 2D OCT images.

RESULTS: A novel software tool entitled Biofilm Imaging and Structure Classification Automatic Processor (BISCAP) is presented. It was developed specifically for the automatic processing of 2D OCT biofilm images. The proposed approach makes use of some of the key principles used in CLSM image processing, and introduces a novel thresholding algorithm and substratum detection strategy. Two complementary pixel continuity checks are executed, enabling very detailed pixel characterizations. BISCAP delivers common structural biofilm parameters and a set of processed images for biofilm analysis. A novel biofilm 'compaction parameter' is suggested. The proposed strategy was tested on a set of 300 images with highly satisfactory results obtained. BISCAP is a Python-based standalone application, not requiring any programming knowledge or property licenses, and where all operations are managed via an intuitive Graphical User Interface. The automatic nature of this image processing strategy decreases biasing problems associated to human-perception and allows a reliable comparison of outputs.

BISCAP and a collection of biofilm images obtained from OCT scans can be found at: https://github.com/diogonarciso/BISCAP.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.}, } @article {pmid34984695, year = {2022}, author = {Farjami, A and Hatami, MS and Siahi-Shadbad, MR and Lotfipour, F}, title = {Peracetic acid activity on biofilm formed by Escherichia coli isolated from an industrial water system.}, journal = {Letters in applied microbiology}, volume = {74}, number = {4}, pages = {613-621}, doi = {10.1111/lam.13647}, pmid = {34984695}, issn = {1472-765X}, mesh = {Biofilms ; *Disinfectants ; Disinfection ; Escherichia coli ; *Peracetic Acid/pharmacology ; Phylogeny ; Water ; }, abstract = {One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96-well microtiter-based calorimetric method was applied in in vitro biofilm production using Escherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed that the isolated bacteria belong to strains of Escherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0·15-0·5% for a contact time of 5-15 min at 20-60°C. The maximum biofilm formation by MTP method using an Escherichia coli isolate was achieved in 96-h incubation in TSB containing wells at 37°C. Biofilm formation rate shown to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0·25%, the temperature of 40°C and a minimum of 10 min of contact time was effective in the eradication of biofilm in an MTP-based system.}, } @article {pmid34982818, year = {2022}, author = {Gemmell, CT and Parreira, VR and Farber, JM}, title = {Controlling Listeria monocytogenes Growth and Biofilm Formation Using Flavonoids.}, journal = {Journal of food protection}, volume = {85}, number = {4}, pages = {639-646}, doi = {10.4315/JFP-21-135}, pmid = {34982818}, issn = {1944-9097}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Flavonoids/pharmacology ; *Listeria monocytogenes ; Stainless Steel ; }, abstract = {ABSTRACT: The aim of this study was to investigate the ability of natural plant-derivate products (flavonoid compounds) to inhibit the growth and biofilm-forming ability of Listeria monocytogenes. A collection of 500 synthetic and natural flavonoids were tested individually on strains of L. monocytogenes for their antimicrobial and antibiofilm activity. The flavonoids were tested against a L. monocytogenes cocktail of five strains at a concentration of 100 μM to determine their effect on planktonic growth. The optical density was measured every hour for 24 h at 37°C, and every hour for 48 h at 22°C. A total of 17 flavonoids were chosen for further study because of their ability to significantly reduce the growth of L. monocytogenes up to 97%. An additional two flavonoids that increased planktonic growth were chosen as well to investigate whether they had the same effect on biofilm growth. A lower concentration of flavonoid compounds (50 μM) was selected to investigate the individual effects on L. monocytogenes biofilm formation using (i) stainless steel coupons to quantify biomass using crystal violet staining and (ii) glass slides using confocal laser scanning microscopic (CLSM) imaging to observe the biofilm architecture. The 19 flavonoids showed various levels of L. monocytogenes biofilm growth inhibition, ranging from 2 to 100% after 48 h of incubation at 22 or 10°C. This includes 18 of the 19 flavonoids significantly (P ≤ 0.05) inhibiting L. monocytogenes biofilm formation on stainless steel coupons under at least one of the testing conditions. However, only one flavonoid compound demonstrated significant biofilm inhibition (P ≤ 0.05) under all conditions tested. Furthermore, 8 of the selected 19 flavonoid compounds showed visible reductions through CLSM in L. monocytogenes biofilm formation. Overall, we identified five flavonoid compounds to be promising antibiofilm and antimicrobial agents against L. monocytogenes.}, } @article {pmid34982373, year = {2022}, author = {Gharaei, S and Ohadi, M and Hassanshahian, M and Porsheikhali, S and Forootanfar, H}, title = {Isolation, Optimization, and Structural Characterization of Glycolipid Biosurfactant Produced by Marine Isolate Shewanella algae B12 and Evaluation of Its Antimicrobial and Anti-biofilm Activity.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {4}, pages = {1755-1774}, pmid = {34982373}, issn = {1559-0291}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Glycolipids/chemistry/pharmacology ; *Petroleum ; *Shewanella/metabolism ; Surface-Active Agents/chemistry ; }, abstract = {Biosurfactants are microbial-derived compounds with surface and emulsifying activities. Environmental and industrial applications make glycolipid biosurfactants particularly interesting among the several categories of biosurfactants. A potential glycolipid biosurfactant resource, Shewanella algae, was isolated from marine samples at the Persian Gulf. The glycolipid biosurfactant caused a reduction in water surface tension from 72 to 43 mN/m with a 0.25 mg/mL critical micelle concentration (CMC). Two-level factorial design was then applied for optimization of biosurfactant production, where a maximal reduction of culture broth surface tension (31 mN/m) acquired in the presence of crude oil (0.5%, v/v), NaNO3 (0.2 g/L), NH4Cl (0.7 g/L), and peptone (0.5 g/L). GC-MS analysis of the culture broth showed when crude oil was used as the sole carbon source, S. algae was able to degrade most of its alkane components. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy revealed the glycolipid structure of biosurfactant. The glycolipid biosurfactant exhibited considerable growth inhibition of clinical bacterial pathogens and disrupted the preformed biofilms of Bacillus cereus (83%), Streptococcus pneumoniae (53%), Pseudomonas aeruginosa (92%), Escherichia coli (64%), Klebsiella pneumoniae (87%), and Acinetobacter sp. (72%). In conclusion, the glycolipid biosurfactant secreted by S. algae exhibited a wide range of functional properties and was evidenced as a promising candidate for biomedical application.}, } @article {pmid34980413, year = {2022}, author = {Cao, Y and Li, L and Zhang, Y and Liu, F and Xiao, X and Li, X and Yu, Y}, title = {Evaluation of Cronobacter sakazakii biofilm formation after sdiA knockout in different osmotic pressure conditions.}, journal = {Food research international (Ottawa, Ont.)}, volume = {151}, number = {}, pages = {110886}, doi = {10.1016/j.foodres.2021.110886}, pmid = {34980413}, issn = {1873-7145}, mesh = {Biofilms ; Cell Membrane ; *Cronobacter sakazakii/genetics ; Humans ; Osmotic Pressure ; }, abstract = {This study characterizes the impact of sdiA on biofilm formation under normal or osmotic stress conditions in Cronobacter sakazakii by constructing a sdiA deletion mutant (ΔsdiA). Here, the downregulation of flagellar assembly-related genes and upregulation of capsular, cellulose and lipopolysaccharide biosynthesis-associated genes in ΔsdiA were observed when compared to the wild type strain (WT) through transcriptomic analysis. Meanwhile, reduced ability of motility, enhanced cell surface hydrophobicity and stronger biofilms with extracellular matrix were observed in WT with deletion of sdiA. Both WT and ΔsdiA formed more biofilm in low osmotic stress medium, while in hyperosmolarity conditions, formation of biofilm was dramatically reduced. Our findings supported that sdiA might suppress biofilm formation of C. sakazakii by regulating biosynthesis of flagellar and extracellular polymeric substances. This study investigates the role of sdiA on biofilm formation in C. sakazakii, and provides the basis for the inhibition of C. sakazakii in food industry and infant-feeding.}, } @article {pmid34980334, year = {2021}, author = {Jia, W and Guo, RL}, title = {[Research Advance on the Factors Influencing Klebsiella Pneumoniae Biofilm Formation and the Regulation Mechanisms].}, journal = {Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae}, volume = {43}, number = {6}, pages = {936-944}, doi = {10.3881/j.issn.1000-503X.13957}, pmid = {34980334}, issn = {1000-503X}, mesh = {Anti-Bacterial Agents ; *Biofilms ; *Klebsiella pneumoniae ; }, abstract = {The biofilm formation is a dynamic process of bacterial growth,and the extracellular components can encase these microorganisms,making them more resistant to antibiotics and host immune attack.The formation of antibiotic-resistant bacterial biofilms will be a major challenge for the treatment and control of clinical infections.Klebsiella pneumoniae is a common clinical pathogen.Hypervirulent K.pneumoniae and carbapenem-resistant K.pneumoniae can cause serious infectious diseases,and the formation of its biofilm will aggravate this situation.In-depth research on the formation of K.pneumoniae biofilm and its regulatory mechanism can shed light on clinical anti-infection treatment and control.This article mainly reviews the latest research progress in the effects of fimbriae,polysaccharides,quorum sensing systems,and efflux pumps on the formation of K.pneumoniae biofilm and their regulatory mechanisms.}, } @article {pmid34979887, year = {2022}, author = {Pecoraro, C and Carbone, D and Deng, D and Cascioferro, SM and Diana, P and Giovannetti, E}, title = {Biofilm Formation as Valuable Target to Fight against Severe Chronic Infections.}, journal = {Current medicinal chemistry}, volume = {29}, number = {25}, pages = {4307-4310}, doi = {10.2174/0929867329666220103095551}, pmid = {34979887}, issn = {1875-533X}, support = {2017E84AA4//PRIN2017/ ; }, mesh = {Anti-Bacterial Agents ; *Biofilms ; Humans ; Microbial Sensitivity Tests ; *Persistent Infection ; }, } @article {pmid34979277, year = {2022}, author = {Li, Z and Feng, Y and Chang, L and Long, Y and Suo, N and Wang, Z and Yu, Y}, title = {Efficient degradation of naproxen in a three dimensional biofilm electrode magnetism reactor (3DBEMR): Removal performance and microbial community.}, journal = {Bioresource technology}, volume = {346}, number = {}, pages = {126653}, doi = {10.1016/j.biortech.2021.126653}, pmid = {34979277}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Electrodes ; *Microbiota ; *Naproxen ; }, abstract = {A three-dimensional biofilm electrode magnetism reactor (3DBEMR) was constructed to removal naproxen (NPX). This study evaluated 3DBEMR performance in removal of refractory NPX, while also discussing the effect of the electro-magnetic superposition on microbial community by high throughput sequencing. Results indicated that 3DBEMR's average removal rate for NPX stood at 88.36%, representing an increase by 75.24%, 65.03% and 12.36%, respectively, compared to 3DBR (Three-Dimensional Biofilm Reactor), 3DBMR (Three-Dimensional Biofilm Magnetism Reactor) and 3DBER (Three-Dimensional Biofilm Electrode Reactor). This was attributed to the influence of electro-magnetic adsorption, electro-oxidaton/catalysis, and electro-magnetic biodegradation. Another major contributing factor to NPX removal was the presence in 3DBEMR of high-abundance genera such as Rhodobacter, Porphyrobacter, Methyloversatilis, Sphingopyxis,Bosea, Singulisphaera, Sphingomonas. Therefore, the 3DBEMR was successfully demonstrated to be a flexible and effective technique in NPX degradation, which would help to better understand the effect of superposition of electric and magnetic fields on microbial community.}, } @article {pmid34979128, year = {2022}, author = {Wu, X and Zhang, L and Lv, Z and Xin, F and Dong, W and Liu, G and Li, Y and Jia, H}, title = {N-acyl-homoserine lactones in extracellular polymeric substances from sludge for enhanced chloramphenicol-degrading anode biofilm formation in microbial fuel cells.}, journal = {Environmental research}, volume = {207}, number = {}, pages = {112649}, doi = {10.1016/j.envres.2021.112649}, pmid = {34979128}, issn = {1096-0953}, mesh = {*Acyl-Butyrolactones/metabolism ; *Bioelectric Energy Sources ; Biofilms ; Chloramphenicol/metabolism ; Electrodes ; Extracellular Polymeric Substance Matrix/metabolism ; Sewage/microbiology ; }, abstract = {Exploring an efficient acclimation strategy to obtain robust bioanodes is of practical significance for antibiotic wastewater treatment by bioelectrochemical systems (BESs). This study investigated the effects of two acclimation conditions on chloramphenicol (CAP)-degrading anode biofilm formation in microbial fuel cells (MFCs). The one was continuously added the extracellular polymeric substances (EPS) extracted from anaerobic sludge and increasing concentrations of CAP after the first start-up phase, while the other was added the EPS-1 (N-acyl-homoserine lactones, namely AHLs were extracted from the EPS) at the same conditions. The results demonstrated that AHLs in the sludge EPS played a crucial role for enhanced CAP-degrading anode biofilm formation in MFCs. The AHL-regulation could not only maintain stable voltage outputs but also significantly accelerate CAP removal in the EPS MFC. The maximum voltage of 653.83 mV and CAP removal rate of 1.21 ± 0.05 mg/L·h were attained from the EPS MFC at 30 mg/L of CAP, which were 0.84 and 1.57 times higher than those from the EPS-1 MFC, respectively. These improvements were largely caused by the thick and 3D structured biofilm, strong and homogeneous cell viability throughout the biofilm, and high protein/polysaccharide ratio along with more conductive contents in the biofilm EPS. Additionally, AHLs facilitated the formation of a biofilm with rich biodiversity and balanced bacterial proportions, leading to more beneficial mutualism among different functional bacteria. More bi-functional bacteria (for electricity generation and antibiotic resistance/degradation) were specifically enriched by AHLs as well. These findings provide quorum sensing theoretical knowledge and practical instruction for rapid antibiotic-degrading electrode biofilm acclimation in BESs.}, } @article {pmid34978741, year = {2022}, author = {Yang, S and Sui, S and Qin, Y and Chen, H and Sha, S and Liu, X and Deng, G and Ma, Y}, title = {Protein O-mannosyltransferase Rv1002c contributes to low cell permeability, biofilm formation in vitro, and mycobacterial survival in mice.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {130}, number = {3}, pages = {181-192}, doi = {10.1111/apm.13204}, pmid = {34978741}, issn = {1600-0463}, mesh = {Animals ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Cell Membrane Permeability/*physiology ; Cytokines/metabolism ; Inflammation/metabolism/microbiology ; Mannosyltransferases/*metabolism ; Mice ; Mice, Inbred BALB C ; Mycobacterium smegmatis/metabolism ; Mycobacterium tuberculosis/metabolism/*pathogenicity ; Permeability ; Virulence/physiology ; }, abstract = {Mycobacterium tuberculosis (M. tuberculosis) Rv1002c encodes the protein O-mannosyltransferase (PMT), which catalyzes the transfer of mannose to serine or threonine residues of proteins. We explored the function of PMT in vitro and in vivo. Rv1002c protein was heterogeneously overexpressed in nonpathogenic Mycobacterium smegmatis (named as MS_Rv1002c). A series of trials including mass spectrometry, transmission electron microscope, biofilm formation and antibiotics susceptibility were performed to explore the function of PMT on bacterial survival in vitro. Mouse experiments were carried out to evaluate the virulence of PMT in vivo. PMT decreased the cell envelope permeability and promoted microbial biofilm formation. PMT enhanced the mycobacterial survival in vivo and inhibited the release of pro-inflammatory cytokines in serum. The function might be associated with an increased abundance of some mannoproteins in culture filtrate (CF). PMT is likely to be involved in mycobacterial survival both in vivo and in vitro due to increasing the mannoproteins abundance in CF.}, } @article {pmid34978461, year = {2022}, author = {Scribner, MR and Stephens, AC and Huong, JL and Richardson, AR and Cooper, VS}, title = {The Nutritional Environment Is Sufficient To Select Coexisting Biofilm and Quorum Sensing Mutants of Pseudomonas aeruginosa.}, journal = {Journal of bacteriology}, volume = {204}, number = {3}, pages = {e0044421}, pmid = {34978461}, issn = {1098-5530}, support = {T32 AI049820/AI/NIAID NIH HHS/United States ; U01 AI124302/AI/NIAID NIH HHS/United States ; U01AI124302/AI/NIAID NIH HHS/United States ; T32AI049820/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Cystic Fibrosis/microbiology ; Humans ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/metabolism ; Quorum Sensing/genetics ; }, abstract = {The evolution of bacterial populations during infections can be influenced by various factors including available nutrients, the immune system, and competing microbes, rendering it difficult to identify the specific forces that select on evolved traits. The genomes of Pseudomonas aeruginosa isolated from the airways of people with cystic fibrosis (CF), for example, have revealed commonly mutated genes, but which phenotypes led to their prevalence is often uncertain. Here, we focus on effects of nutritional components of the CF airway on genetic adaptations by P. aeruginosa grown in either well-mixed (planktonic) or biofilm-associated conditions. After only 80 generations of experimental evolution in a simple medium with glucose, lactate, and amino acids, all planktonic populations diversified into lineages with mutated genes common to CF infections: morA, encoding a regulator of biofilm formation, or lasR, encoding a quorum sensing regulator that modulates the expression of virulence factors. Although mutated quorum sensing is often thought to be selected in vivo due to altered virulence phenotypes or social cheating, isolates with lasR mutations demonstrated increased fitness when grown alone and outcompeted the ancestral PA14 strain. Nonsynonymous SNPs in morA increased fitness in a nutrient concentration-dependent manner during planktonic growth and surprisingly also increased biofilm production. Populations propagated in biofilm conditions also acquired mutations in loci associated with chronic infections, including lasR and cyclic di-GMP regulators roeA and wspF. These findings demonstrate that nutrient conditions and biofilm selection are sufficient to select mutants with problematic clinical phenotypes including increased biofilm and altered quorum sensing. IMPORTANCE Pseudomonas aeruginosa produces dangerous chronic infections that are known for their rapid diversification and recalcitrance to treatment. We performed evolution experiments to identify adaptations selected by two specific aspects of the CF respiratory environment: nutrient levels and surface attachment. Propagation of P. aeruginosa in nutrients present within the CF airway was sufficient to drive diversification into subpopulations with identical mutations in regulators of biofilm and quorum sensing to those arising during infection. Thus, the adaptation of opportunistic pathogens to nutrients found in the host may select mutants with phenotypes that complicate treatment and clearance of infection.}, } @article {pmid34976872, year = {2021}, author = {Mhade, S and Panse, S and Tendulkar, G and Awate, R and Narasimhan, Y and Kadam, S and Yennamalli, RM and Kaushik, KS}, title = {AMPing Up the Search: A Structural and Functional Repository of Antimicrobial Peptides for Biofilm Studies, and a Case Study of Its Application to Corynebacterium striatum, an Emerging Pathogen.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {803774}, pmid = {34976872}, issn = {2235-2988}, mesh = {*Antimicrobial Peptides/chemistry/pharmacology ; *Biofilms ; *Corynebacterium ; Molecular Docking Simulation ; }, abstract = {Antimicrobial peptides (AMPs) have been recognized for their ability to target processes important for biofilm formation. Given the vast array of AMPs, identifying potential anti-biofilm candidates remains a significant challenge, and prompts the need for preliminary in silico investigations prior to extensive in vitro and in vivo studies. We have developed Biofilm-AMP (B-AMP), a curated 3D structural and functional repository of AMPs relevant to biofilm studies. In its current version, B-AMP contains predicted 3D structural models of 5544 AMPs (from the DRAMP database) developed using a suite of molecular modeling tools. The repository supports a user-friendly search, using source, name, DRAMP ID, and PepID (unique to B-AMP). Further, AMPs are annotated to existing biofilm literature, consisting of a vast library of over 10,000 articles, enhancing the functional capabilities of B-AMP. To provide an example of the usability of B-AMP, we use the sortase C biofilm target of the emerging pathogen Corynebacterium striatum as a case study. For this, 100 structural AMP models from B-AMP were subject to in silico protein-peptide molecular docking against the catalytic site residues of the C. striatum sortase C protein. Based on docking scores and interacting residues, we suggest a preference scale using which candidate AMPs could be taken up for further in silico, in vitro and in vivo testing. The 3D protein-peptide interaction models and preference scale are available in B-AMP. B-AMP is a comprehensive structural and functional repository of AMPs, and will serve as a starting point for future studies exploring AMPs for biofilm studies. B-AMP is freely available to the community at https://b-amp.karishmakaushiklab.com and will be regularly updated with AMP structures, interaction models with potential biofilm targets, and annotations to biofilm literature.}, } @article {pmid34976858, year = {2021}, author = {Buck, LD and Paladino, MM and Nagashima, K and Brezel, ER and Holtzman, JS and Urso, SJ and Ryno, LM}, title = {Temperature-Dependent Influence of FliA Overexpression on PHL628 E. coli Biofilm Growth and Composition.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {775270}, pmid = {34976858}, issn = {2235-2988}, mesh = {Biofilms/*growth & development ; *Escherichia coli/genetics/growth & development ; *Extracellular Polymeric Substance Matrix ; Sigma Factor/*genetics ; Temperature ; }, abstract = {Biofilm growth and survival pose a problem in both medical and industrial fields. Bacteria in biofilms are more tolerant to antibiotic treatment due to the inability of antibiotics to permeate to the bottom layers of cells in a biofilm and the creation of altered microenvironments of bacteria deep within the biofilm. Despite the abundance of information we have about E. coli biofilm growth and maturation, we are still learning how manipulating different signaling pathways influences the formation and fitness of biofilm. Understanding the impact of signaling pathways on biofilm formation may narrow the search for novel small molecule inhibitors or activators that affect biofilm production and stability. Here, we study the influence of the minor sigma transcription factor FliA (RpoF, sigma-28), which controls late-stage flagellar assembly and chemotaxis, on biofilm production and composition at various temperatures in the E. coli strain PHL628, which abundantly produces the extracellular structural protein curli. We examined FliA's influence on external cellular structures like curli and flagella and the biomolecular composition of the biofilm's extracellular polymeric substance (EPS) using biochemical assays, immunoblotting, and confocal laser scanning microscopy (CLSM). At 37°C, FliA overexpression results in the dramatic growth of biofilm in polystyrene plates and more modest yet significant biofilm growth on silica slides. We observed no significant differences in curli concentration and carbohydrate concentration in the EPS with FliA overexpression. Still, we did see significant changes in the abundance of EPS protein using CLSM at higher growth temperatures. We also noticed increased flagellin concentration, a major structural protein in flagella, occurred with FliA overexpression, specifically in planktonic cultures. These experiments have aided in narrowing our focus to FliA's role in changing the protein composition of the EPS, which we will examine in future endeavors.}, } @article {pmid34975928, year = {2021}, author = {Fu, W and Liu, Y and Liu, F and Liu, C and Li, J and Niu, J and Han, P and Xu, D and Hou, J and Ma, Y and Feng, J and Li, Z and Mu, R and Yang, G}, title = {Corrigendum: A Novel Autoantibody Induced by Bacterial Biofilm Conserved Components Aggravates Lupus Nephritis.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {819846}, doi = {10.3389/fimmu.2021.819846}, pmid = {34975928}, issn = {1664-3224}, abstract = {[This corrects the article DOI: 10.3389/fimmu.2021.656090.].}, } @article {pmid34974103, year = {2022}, author = {Behera, B and Laavanya, D and Balasubramanian, P}, title = {Techno-economic feasibility assessment of bacterial cellulose biofilm production during the Kombucha fermentation process.}, journal = {Bioresource technology}, volume = {346}, number = {}, pages = {126659}, doi = {10.1016/j.biortech.2021.126659}, pmid = {34974103}, issn = {1873-2976}, mesh = {*Bacteria ; Biofilms ; *Cellulose ; Feasibility Studies ; Fermentation ; }, abstract = {Bacterial cellulose produced during Kombucha fermentation has recently received lots of attention owing to its desirable mechanical and physicochemical properties and is exploited for different food, textiles and environmental applications. However, lack of information on process feasibility often hinders large-scale manufacturing of Kombucha-based cellulose. Therefore, the current study assesses techno-economic feasibility of a 60-ton annual capacity Kombucha-based cellulose production facility using SuperPro designer. Economic feasibility analysis showed an estimation of 13.72 million US$ as total investment and 3.8 million US$ as operating costs with 89% expenses associated with facility dependent and labour costs. The process feasibility is revealed with a payback time of 4.23 years, 23.64% return on investment and 16.48% internal rate of return. Sensitivity analysis presented that increased volume of fermentation units and automating the process can significantly reduce input costs. Such research is necessary to aid policymakers in facilitating the commercialization of Kombucha-based cellulose at field scale.}, } @article {pmid34973549, year = {2022}, author = {Pawluk, AM and Kim, D and Jin, YH and Jeong, KC and Mah, JH}, title = {Biofilm-associated heat resistance of Bacillus cereus spores in vitro and in a food model, Cheonggukjang jjigae.}, journal = {International journal of food microbiology}, volume = {363}, number = {}, pages = {109505}, doi = {10.1016/j.ijfoodmicro.2021.109505}, pmid = {34973549}, issn = {1879-3460}, mesh = {*Bacillus cereus ; Biofilms ; Food Microbiology ; Food Safety ; Hot Temperature ; *Spores, Bacterial ; }, abstract = {Bacillus cereus, a foodborne pathogen, is capable of forming spores and biofilms as methods to withstand environmental stresses. These bacterial structures are an issue for food safety as they aid the bacteria survive heat sterilisation processes of foods and food contact surfaces. This study was conducted to investigate the role of the biofilm structure in providing an extra layer of protection to spores against heat treatments. For this, heat resistance of B. cereus spores in intact biofilms was compared to that of planktonic spores in vitro and in a Cheonggukjang jjigae food model. Using methods developed in this study to measure the wet and dry heat resistance of spores in intact biofilms, it was found that B. cereus spores have significantly higher heat resistances when present in biofilms rather than as planktonic spores, and that dry heat is less effective than wet heat at killing spores in biofilms. In further detail, for wet heat treatments, spores in biofilms of the strain isolated from Cheonggukjang (Korean fermented whole soybean), B. cereus CH3, had generally higher wet heat resistances than the reference strain, B. cereus ATCC 10987, both in vitro and in the Cheonggukjang jjigae food model. However, the spores in biofilms of the two strains showed similar heat resistance to dry heat, with some exceptions, when biofilms were formed in vitro or in Cheonggukjang jjigae broth. Meanwhile, B. cereus ATCC 10987 spores in biofilms had higher or similar wet heat resistances in vitro compared to in Cheonggukjang jjigae broth. Wet heat resistances of B. cereus CH3 spores in biofilms were all statistically similar regardless of biofilm formation media (brain heart infusion and Cheonggukjang jjigae broths). For dry heat, spores in biofilms of both B. cereus strains were more heat resistant when biofilms were formed in the Cheonggukjang jjigae food model rather than in vitro. Altogether, heat resistances of spores in biofilms formed in vitro and in the food environment were found to be different depending on the tested B. cereus strain, but higher than planktonic spores in any case. This is the first study examining the heat resistance of B. cereus spores in intact biofilms matrices attached to the surface, both in vitro and in a food model. Therefore, this research is valuable to understand the protective effects of biofilms formed in food environments and to reduce the food safety risks associated with B. cereus.}, } @article {pmid34973331, year = {2022}, author = {Ni, M and Chen, Y and Pan, Y and Huang, Y and Li, DP and Li, L and Huang, B and Song, Z}, title = {Study on community structure and metabolic mechanism of dominant polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in suspended biofilm based on phosphate recovery.}, journal = {The Science of the total environment}, volume = {815}, number = {}, pages = {152678}, doi = {10.1016/j.scitotenv.2021.152678}, pmid = {34973331}, issn = {1879-1026}, mesh = {Biofilms ; *Bioreactors ; *Glycogen ; Phosphorus ; Polyphosphates ; }, abstract = {Biofilm sequencing batch reactor (BSBR) can achieve efficient phosphate (P) removal and enrichment, but its process performance and metabolic mechanisms for P removal and enrichment of municipal wastewater remain largely unclear. In the present study, we assessed the P removal and enrichment of municipal wastewater at influent P concentrations of 2.5 mg/L and 10 mg/L. The efficiency of P removal and enzyme activity in polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) were compared, and the growth and metabolic characteristics of dominant PAOs and GAOs at different influent P concentrations were studied with the macro-sequencing technology. The results showed that the P recovery efficiencies were 70.03% and 76.19% when the influent P concentration was 2.5 mg/L and 10 mg/L in BSBR, respectively, and the maximum P concentration of recovery liquid was 81.29 mg/L and 173.12 mg/L, respectively. There were no phosphate kinase (PPK) and phosphate hydrolase (PPX) in extracellular polymeric substances (EPS). The dominant PAOs were Candidatus_Contendobacter, Dechloromonas, and Flavobacterium, and the dominant GAO was Candidatus_Competibacter. The abundance of Candidatus_Contendobacter was the highest with the most potential contribution to P removal. PAOs had competitive advantages in carbon (C) source uptake, glycogen metabolism, P metabolism, and adenosine triphosphate (ATP) metabolism. HMP was unique to PAOs, EMP had the highest abundance in glycogen metabolism, and ED was contained in PAOs of BSBR. These results indicated that BSBR provided sufficient reducing power and ATP for PAOs through different glycogen decomposition pathways to promote P uptake and obtained competitive advantages in P metabolism, C source uptake, and ATP utilization to achieve efficient P removal and enrichment. Collectively, our current findings provided valuable insights into the P removal and enrichment mechanism of BSBR in municipal sewage.}, } @article {pmid34972879, year = {2021}, author = {Heredia, M and Andes, D}, title = {Contributions of Extracellular Vesicles to Fungal Biofilm Pathogenesis.}, journal = {Current topics in microbiology and immunology}, volume = {432}, number = {}, pages = {67-79}, pmid = {34972879}, issn = {0070-217X}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; Candida albicans ; Cell Wall ; Drug Resistance, Fungal ; *Extracellular Vesicles ; }, abstract = {Extracellular vesicles (EVs) are produced by all kingdoms of life and have been increasingly recognized as a key aspect of microbial pathogenicity. These membrane-bound compartments serve as secretory vehicles for the delivery of macromolecules to the extracellular environment. Studies over the past several decades have revealed that microbial EVs are highly suited to the biology and environmental context of the organism secreting them. Fungal EVs have been described in at least 12 species and have diverse functions. These functions include, but are not limited to, molecular transport across the cell wall, immunomodulation, cell-cell communication, export of virulence factors and nucleic acids, extracellular matrix (ECM) production, and induction of drug resistance. This chapter will explore the contributions of EVs to fungal pathogenesis and virulence, with a detailed focus on the role of C. albicans biofilm EVs in matrix biogenesis and antifungal resistance. Brief commentary on EV function in bacterial biofilms will also be provided for comparison, and suggestions for areas of future investigation in this field will be discussed.}, } @article {pmid34969452, year = {2022}, author = {Zhang, X and Sun, J and Zhao, M}, title = {Enhanced metronidazole removal by binary-species photoelectrogenic biofilm of microaglae and anoxygenic phototrophic bacteria.}, journal = {Journal of environmental sciences (China)}, volume = {115}, number = {}, pages = {25-36}, doi = {10.1016/j.jes.2021.07.016}, pmid = {34969452}, issn = {1001-0742}, mesh = {Biofilms ; *Chlorella vulgaris ; Extracellular Polymeric Substance Matrix ; Metronidazole/analysis ; *Microalgae ; Wastewater ; *Water Purification ; }, abstract = {High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co-exist with nutriments in wastewater and resist biodegradation due to their strong biotoxicity and recalcitrance. In this study, we make a first attempt to enhance metronidazole (MNZ) removal from wastewater using electrochemistry-activated binary-species photosynthetic biofilm of Rhodopseudomonas Palustris (R. Palustris) and Chlorella vulgaris (C. vulgaris) by cultivating them under different applied potentials. The results showed that application of external potentials of -0.3, 0 and 0.2 V led to 11, 33 and 26-fold acceleration in MNZ removal, respectively, as compared to that of potential free. The extent of enhancement in MNZ removal was positively correlated to the intensities of photosynthetic current produced under different externally applied potentials. The binary-species photoelectrogenic biofilm exhibited 18 and 6-fold higher MNZ removal rate than that of single-species of C. vulgaris and R. Palustris, respectively, due to the enhanced metabolic interaction between them. Application of an external potential of 0V significantly promoted the accumulation of tryptophan and tyrosine-like compounds as well as humic acid in extracellular polymeric substance, whose concentrations were 7.4, 7.1 and 2.0-fold higher than those produced at potential free, contributing to accelerated adsorption and reductive and photosensitive degradation of MNZ.}, } @article {pmid34968430, year = {2022}, author = {Tong, CY and Derek, CJC}, title = {Membrane surface roughness promotes rapid initial cell adhesion and long term microalgal biofilm stability.}, journal = {Environmental research}, volume = {206}, number = {}, pages = {112602}, doi = {10.1016/j.envres.2021.112602}, pmid = {34968430}, issn = {1096-0953}, mesh = {Biofilms ; Cell Adhesion ; Extracellular Polymeric Substance Matrix/metabolism ; Membranes ; *Microalgae ; Surface Properties ; }, abstract = {In biofilm membrane photobioreactors development, conscientious works revolving around the effect of external environment factors on microalgal biofilm growth were assessed but more comparative research about the role of carrier surfaces properties such as surface roughness is necessary. Thus, commercial polyethersulfone (PES) membranes with two different molecular-weight-cut-offs (1 kDa and 30 kDa) were selected as the main representatives of surface roughness in a 20 days long-term biofilm cultivation experiment under dynamic flow condition for the biofilm evolvement of three benthic diatoms (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta). Results depicted that rougher 30 kDa PES enable higher cell attachment degree for C. fusiformis (25.85 ± 2.75 × 10[9] cells m[-2]), followed by A. coffeaeformis (11.86 ± 2.76 × 10[9] cells m[-2]) and N. incerta (10.10 ± 0.65 × 10[9] cells m[-2]). Bounded extracellular polymeric substances (bEPS) gathered were relatively higher than soluble EPS (sEPS) while bEPS accumulated at least 10% higher on smooth 1 kDa PES than rough 30 kDa PES for the purpose of enhancing the biofilm disruption resistivity under liquid flow. Moreover, cell adhesion mechanism was proposed via computational fluid dynamics in parallel with EPS analysis. Copious amount of asperities and stagnant zones present on rough 30 kDa surfaces accelerated biofilm development and the consistency of the results have a great valence for interpretation of microalgal biofilm lifestyle on porous surfaces.}, } @article {pmid34968154, year = {2022}, author = {Chen, Q and Xu, L and Wu, T and Li, J and Hua, L}, title = {Analysis of abnormal intestinal flora on risk of intestinal cancer and effect of heparin on formation of bacterial biofilm.}, journal = {Bioengineered}, volume = {13}, number = {1}, pages = {894-904}, pmid = {34968154}, issn = {2165-5987}, mesh = {Bacteria/*classification/growth & development/isolation & purification ; Biofilms/growth & development ; Case-Control Studies ; Endotoxins/*blood ; Feces/microbiology ; Female ; Gastrointestinal Microbiome ; Heparin/*metabolism ; Humans ; Intestinal Neoplasms/microbiology/*surgery ; Lactic Acid/*blood ; Male ; Phylogeny ; }, abstract = {To study the effect of abnormal intestinal flora on the risk of colorectal cancer and the effect of heparin on the formation of bacterial biofilm, 50 patients with colorectal cancer and 50 healthy subjects were selected. The distribution and quantity of bacteria in feces, the levels of D-lactic acid and endotoxin in serum of the two groups were detected. Intestinal flora strains and biofilm growth were also detected in patients with colorectal cancer cultured in different heparin concentrations (0 mg/mL, 5 mg /mL, 10 mg/mL, and 20 mg/mL). The results showed that there was significant difference in the number of major strains of intestinal flora between healthy subjects and colorectal cancer patients before and after operation (P < 0.05). The serum D-lactic acid levels (1.41 ± 0.39, 6.38 ± 1.42 μg/mL) and endotoxin levels (0.62 ± 0.09, 0.80 ± 0.15 EU/mL) in the experimental group were higher than those in the control group (0.91 ± 0.52 μg/mL) (0.05 ± 0.02 EU/mL) before and after operation (P < 0.05). The amount of biofilm formation increased significantly with the increase of heparin concentration (P < 0.05). In summary, there was a close relationship between the occurrence of colorectal cancer and abnormal intestinal flora. Heparin may have a positive effect on regulating intestinal flora in patients with colorectal cancer, which provided certain reference value for the treatment of colorectal cancer.}, } @article {pmid34966438, year = {2021}, author = {Neglo, D and Tettey, CO and Essuman, EK and Amenu, JD and Mills-Robertson, FC and Sedohia, D and Boakye, AA and Abaye, DA}, title = {Evaluation of the Modulatory Effect of Annona muricata Extracts on the Activity of Some Selected Antibiotics against Biofilm-Forming MRSA.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2021}, number = {}, pages = {9342110}, pmid = {34966438}, issn = {1741-427X}, abstract = {The study investigated the influence of Annona muricata extracts on the action of selected antibiotics against biofilm-forming MRSA. The various parts of the plant were processed into powder and extracted with ethanol or hot water and then screened for the presence of phytochemicals. The modulatory effect of the Annona muricata extract was also tested on some antibiotics against Methicillin-resistant Staphylococcus aureus (MRSA). The findings from this study revealed that the various parts of the Annona muricata extract (ethanolic and aqueous) contained different proportions of secondary metabolites. Varied antimicrobial activities were observed when the extract of the A. muricata was exposed to MRSA strain at a concentration of 100 mg/mL. The stem recorded the highest (17.00 and 18.00 mm) inhibitory activity against MRSA for both the aqueous and the ethanolic extract, respectively, and this was not different from the control, tetracycline. Again, the results on the modulatory action indicated that out of the 10 extracts of A. muricata, 4 of them antagonized the activity of ampicillin against the tested MRSA by a factor of 0.5 folds and the rest potentiated the drug within 1-4 folds, respectively. On the other hand, the various test extracts significantly potentiated the efficacy of streptomycin and tetracycline against the MRSA by a range of 1-32 folds with the aqueous root extract recording the highest synergistic effect and ethanol seed extract with the least effect. The findings of this study support the antibacterial activities of the A. muricata plant parts.}, } @article {pmid34964907, year = {2021}, author = {Haris, M and Chen, C and Wu, J and Ramzan, MN and Taj, A and Sha, S and Ullah, H and Ma, Y}, title = {Inducible knockdown of Mycobacterium smegmatis MSMEG_2975 (glyoxalase II) affected bacterial growth, antibiotic susceptibility, biofilm, and transcriptome.}, journal = {Archives of microbiology}, volume = {204}, number = {1}, pages = {97}, pmid = {34964907}, issn = {1432-072X}, support = {81573469//National Natural Science Foundation of China (CN)/ ; 81930112//National Natural Science Foundation of China (CN)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; *Mycobacterium smegmatis/genetics ; Thiolester Hydrolases ; *Transcriptome ; }, abstract = {Tuberculosis (TB) causes millions of deaths each year across the globe. Multiple drug-resistant (MDR) and extensively drug-resistant (XDR) mycobacterial strains have made the treatment extremely difficult. To overcome this hurdle, the development of new drug targets and an effective treatment strategy are desperately needed. This can be achieved by deciphering the role of essential genes and enzymes which are involved in cell survival. One such enzyme is glyoxalase II. The glyoxalase system (glyoxalase I and glyoxalase II) has a pivotal role in cellular survival and detoxification by converting methylglyoxal (MG) into lactate. Otherwise, the increased concentration of MG then modifies DNA, proteins, and lipids, resulting in abnormalities and cell death. Interestingly, the function and physiological role of glyoxalase II have remained undetermined in mycobacteria. In this study, the functional activity of MSMEG_2975 (putative glyoxalase II) after heterologous cloning and expression was determined. And the knockdown strain Mycobacterium smegmatis KD for MSMEG_2975 was constructed with tetracycline-inducible vector pMIND. The inducible knockdown of MSMEG_2975 affected bacterial growth, biofilm formation, transcriptome, and enhanced the susceptibility to antibiotics. This work represents mycobacterial glyoxalase II as a potential drug target against mycobacterial pathogens and indicates the crucial regulatory role of glyoxalase II in mycobacteria.}, } @article {pmid34964290, year = {2021}, author = {Baliarda, A and Winkler, M and Tournier, L and Tinsley, CR and Aymerich, S}, title = {Dynamic interspecies interactions and robustness in a four-species model biofilm.}, journal = {MicrobiologyOpen}, volume = {10}, number = {6}, pages = {e1254}, pmid = {34964290}, issn = {2045-8827}, mesh = {Bacillus cereus/physiology ; Biofilms/*growth & development ; Ecosystem ; *Microbial Interactions ; *Microbiota ; Micrococcaceae/physiology ; Peptides/metabolism ; Plankton/physiology ; Pseudomonas fluorescens/physiology ; Rhodocyclaceae/physiology ; }, abstract = {Interspecific interactions within biofilms determine relative species abundance, growth dynamics, community resilience, and success or failure of invasion by an extraneous organism. However, deciphering interspecific interactions and assessing their contribution to biofilm properties and function remain a challenge. Here, we describe the constitution of a model biofilm composed of four bacterial species belonging to four different genera (Rhodocyclus sp., Pseudomonas fluorescens, Kocuria varians, and Bacillus cereus), derived from a biofilm isolated from an industrial milk pasteurization unit. We demonstrate that the growth dynamics and equilibrium composition of this biofilm are highly reproducible. Based on its equilibrium composition, we show that the establishment of this four-species biofilm is highly robust against initial, transient perturbations but less so towards continuous perturbations. By comparing biofilms formed from different numbers and combinations of the constituent species and by fitting a growth model to the experimental data, we reveal a network of dynamic, positive, and negative interactions that determine the final composition of the biofilm. Furthermore, we reveal that the molecular determinant of one negative interaction is the thiocillin I synthesized by the B. cereus strain, and demonstrate its importance for species distribution and its impact on robustness by mutational analysis of the biofilm ecosystem.}, } @article {pmid34963419, year = {2023}, author = {Admane, N and Kothandan, R and Syed, S and Biswas, S}, title = {A quinoline alkaloid potentially modulates the amyloidogenic structural transitions of the biofilm scaffolding small basic protein.}, journal = {Journal of biomolecular structure & dynamics}, volume = {41}, number = {4}, pages = {1366-1377}, doi = {10.1080/07391102.2021.2020165}, pmid = {34963419}, issn = {1538-0254}, mesh = {Biofilms ; Amyloid/metabolism ; *Alkaloids/pharmacology ; Camptothecin/pharmacology ; *Quinolines/pharmacology ; }, abstract = {Bacterial biofilm formation by communities of opportunistic bacterial pathogens like Staphylococcus epidermidis is regarded as the primary virulence mechanism facilitating the spread of detrimental nosocomial and implant-associated infections. An 18-kDa small basic protein (Sbp) and its amyloid fibrils account for strengthening the biofilm architecture and scaffolding the S. epidermidis biofilm matrix. Our study reports systematic analysis of the amyloidogenic structural transitions of Sbp and predicts the amyloid core of the protein which may trigger misfolding and aggregation. Herein, we report the novel amyloid inhibitory potential of Camptothecin, a quinoline alkaloid which binds stably to Sbp monomers and redirects the formation of unstructured regions further destabilizing the protein. Molecular dynamics simulations reveal that Camptothecin averts β-sheet transitions, interrupts with electrostatic interactions and disrupts the intermolecular hydrophobic associations between the exposed hydrophobic amyloidogenic regions of Sbp. Collectively, our study puts forward the first report detailing the heteromolecular associations and amyloid modulatory effects of Camptothecin which may serve as a structural scaffold for the tailored designing of novel drugs targeting the S. epidermidis biofilm matrix.Communicated by Ramaswamy H. Sarma.}, } @article {pmid34962953, year = {2021}, author = {Harley, BK and Neglo, D and Tawiah, P and Pipim, MA and Mireku-Gyimah, NA and Tettey, CO and Amengor, CD and Fleischer, TC and Waikhom, SD}, title = {Bioactive triterpenoids from Solanum torvum fruits with antifungal, resistance modulatory and anti-biofilm formation activities against fluconazole-resistant candida albicans strains.}, journal = {PloS one}, volume = {16}, number = {12}, pages = {e0260956}, pmid = {34962953}, issn = {1932-6203}, mesh = {Antifungal Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*physiology ; *Drug Resistance, Fungal/drug effects ; Fluconazole/*pharmacology ; Fruit/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/isolation & purification/pharmacology ; Solanum/*chemistry ; Triterpenes/chemistry/isolation & purification/*pharmacology ; }, abstract = {Vulvovaginal candidiasis (VVC) is the second most common vaginal infection that affects women of reproductive age. Its increased occurrence and associated treatment cost coupled to the rise in resistance of the causative pathogen to current antifungal therapies has necessitated the need for the discovery and development of novel effective antifungal agents for the treatment of the disease. We report in this study the anti-Candida albicans activity of Solanum torvum 70% ethanol fruit extract (STF), fractions and some isolated compounds against four (4) fluconazole-resistant strains of C. albicans. We further report on the effect of the isolated compounds on the antifungal activity of fluconazole and voriconazole in the resistant isolates as well as their inhibitory effect on C. albicans biofilm formation. STF was fractionated using n-hexane, chloroform (CHCl3) and ethyl acetate (EtOAc) to obtain four respective major fractions, which were then evaluated for anti-C. albicans activity using the microbroth dilution method. The whole extract and fractions recorded MICs that ranged from 0.25 to 16.00 mg/mL. From the most active fraction, STF- CHCl3 (MIC = 0.25-1.00 mg/mL), four (4) known compounds were isolated as Betulinic acid, 3-oxo-friedelan-20α-oic acid, Sitosterol-3-β-D-glucopyranoside and Oleanolic acid. The compounds demonstrated considerably higher antifungal activity (0.016 to 0.512 mg/mL) than the extract and fractions and caused a concentration-dependent anti-biofilm formation activity. They also increased the sensitivity of the C. albicans isolates to fluconazole. This is the first report of 3-oxo-friedelan-20α-oic acid in the plant as well as the first report of betulinic acid, sitosterol-3-β-D-glucopyranoside and oleanolic acid from the fruits of S. torvum. The present study has demonstrated the anti-C. albicans activity of the constituents of S. torvum ethanol fruit extract and also shown that the constituents possess anti-biofilm formation and resistance modulatory activities against fluconazole-resistant clinical C. albicans isolates.}, } @article {pmid34961640, year = {2022}, author = {Giacomodonato, MN and Sarnacki, SH and Aya Castañeda, MDR and Garófalo, AN and Betancourt, DM and Cerquetti, MC and Noto Llana, M}, title = {Salmonella enterica serovar Enteritidis biofilm lifestyle induces lower pathogenicity and reduces inflammatory response in a murine model compared to planktonic bacteria.}, journal = {Revista Argentina de microbiologia}, volume = {54}, number = {3}, pages = {166-174}, doi = {10.1016/j.ram.2021.10.003}, pmid = {34961640}, issn = {0325-7541}, mesh = {Animals ; Biofilms ; Disease Models, Animal ; Humans ; Life Style ; Mice ; Mice, Inbred BALB C ; Plankton ; *Salmonella Infections, Animal/microbiology ; *Salmonella enteritidis/physiology ; Virulence ; }, abstract = {Salmonellaenterica serovar Enteritidis (S. Enteritidis) is the most frequent serovar involved in human salmonellosis. It has been demonstrated that about 80% of infections are related to biofilm formation. There is scant information about the pathogenicity of S. Enteritidis and its relationship to biofilm production. In this regard, this study aimed to investigate the differential host response induced by S. Enteritidis biofilm and planktonic lifestyle. To this purpose, biofilm and planktonic bacteria were inoculated to BALB/c mice and epithelial cell culture. Survival studies revealed that biofilm is less virulent than planktonic cells. Reduced signs of intestinal inflammation and lower bacterial translocation were observed in animals inoculated with Salmonella biofilm compared to the planktonic group. Results showed that Salmonella biofilm was impaired for invasion of non-phagocytic cells and induces a lower inflammatory response in vivo and in vitro compared to that of planktonic bacteria. Taken together, the outcome of Salmonella-host interaction varies depending on the bacterial lifestyle.}, } @article {pmid34961432, year = {2021}, author = {Lotfali, E and Fattahi, M and Ghasemi, R and Zakermashhadi, F and Shafiei, M and Borzouie, M and Rabiei, MM}, title = {Enhancement of the Anti-biofilm Activity of Gold Nanoparticles- Itraconazole Conjugates in Resistant Candida glabrata.}, journal = {Recent advances in anti-infective drug discovery}, volume = {16}, number = {2}, pages = {137-147}, doi = {10.2174/2772434416666210607144543}, pmid = {34961432}, issn = {2772-4352}, mesh = {Biofilms ; Candida glabrata ; Gold ; *Itraconazole/pharmacology ; *Metal Nanoparticles ; }, abstract = {INTRODUCTION: Onychomycosis, also called tinea unguium, is a common fungal infection affecting the nails. After dermatophytes, Candida species are recognized as second-line pathogens responsible for this infection. The treatment of onychomycosis requires a long time and is associated with high rates of recurrence. Antifungal medicines conjugated with gold (Au-NP) nanoparticle are the possible platforms for the reduction of drug resistance.

METHODS: In the present study, we reported the in-vitro antifungal activity of itraconazole (ITZ) - Au conjugates, time-kill studies, and biofilm-producing ability of six ITZ-resistant C. glabrata.

RESULTS: 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium bromide (MTT) quantitative results revealed that four out of six resistant isolates studied able to form biofilms in vitro. ITZ-Au conjugates were more effective than ITZ or Au nanoparticle alone, and the time-kill tests pointed to the suitable effect of ITZ-Au conjugate.

CONCLUSION: The present study concluded that ITZ-Au conjugates have an inhibitory effect on the biofilm of resistant C. glabrata isolates. Further studies are needed to compare the ex-vivo onychomycosis model.}, } @article {pmid34961388, year = {2022}, author = {Jothipandiyan, S and Suresh, D and Sankaran, SV and Thamotharan, S and Shanmugasundaram, K and Vincent, P and Sekaran, S and Gowrishankar, S and Pandian, SK and Paramasivam, N}, title = {Heteroleptic pincer palladium(II) complex coated orthopedic implants impede the AbaI/AbaR quorum sensing system and biofilm development by Acinetobacter baumannii.}, journal = {Biofouling}, volume = {38}, number = {1}, pages = {55-70}, doi = {10.1080/08927014.2021.2015336}, pmid = {34961388}, issn = {1029-2454}, mesh = {*Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Molecular Docking Simulation ; Palladium/pharmacology ; *Quorum Sensing ; }, abstract = {Implant-associated infections mediated by Acinetobacter baumannii biofilms have become a major concern in the healthcare sector. As biofilm formation by this important pathogen is mediated by quorum sensing, quorum sensing inhibitors (QSI) have gained much attention. The present study confirms that novel thiazolinyl-picolinamide based palladium(II) complexes had good biofilm disruptive and QSI properties against A. baumannii. Key QS-mediated virulence factors like pili mediated surface motility and polysaccharide production were inhibited by the best Pd(II) complex (E). This also showed potent inhibitory activity against both the standard and clinical strains of A. baumannii. Molecular docking analysis also proved the potent binding affinity of Pd(II)-E with the virulence targets. The Pd(II) complex also disrupted preformed biofilms and down-regulated the expression of QS mediated virulence genes in the biofilms established on implant material (titanium plates). As a whole, the present study showed that the novel thiazolinyl-picolinamide based Pd(II) complexes offer a promising anti-infective strategy to combat biofilm-mediated implant infections.}, } @article {pmid34959781, year = {2021}, author = {Amoah, YS and Rajasekharan, SK and Reifen, R and Shemesh, M}, title = {Chickpea-Derived Prebiotic Substances Trigger Biofilm Formation by Bacillus subtilis.}, journal = {Nutrients}, volume = {13}, number = {12}, pages = {}, pmid = {34959781}, issn = {2072-6643}, mesh = {Amino Acids, Sulfur/biosynthesis ; Bacillus subtilis/*growth & development ; Biofilms/*growth & development ; Cicer/*microbiology ; Feasibility Studies ; Functional Food/*microbiology ; Humans ; Piperidines ; Prebiotics/*microbiology ; Probiotics/analysis ; Synbiotics/analysis ; Tissue Scaffolds ; }, abstract = {Chickpea-based foods are known for their low allergenicity and rich nutritional package. As an essential dietary legume, chickpea is often processed into milk or hummus or as an industrial source of protein and starch. The current study explores the feasibility of using the chickpea-derived prebiotic substances as a scaffold for growing Bacillus subtilis (a prospective probiotic bacterium) to develop synbiotic chickpea-based functional food. We report that the chickpea-derived fibers enhance the formation of the B. subtilis biofilms and the production of the antimicrobial pigment pulcherrimin. Furthermore, electron micrograph imaging confirms the bacterial embedding onto the chickpea fibers, which may provide a survival tactic to shield and protect the bacterial population from environmental insults. Overall, it is believed that chickpea-derived prebiotic substances provide a staple basis for developing functional probiotics and synbiotic food.}, } @article {pmid34959736, year = {2021}, author = {Lagha, R and Abdallah, FB and Mezni, A and Alzahrani, OM}, title = {Effect of Plasmonic Gold Nanoprisms on Biofilm Formation and Heat Shock Proteins Expression in Human Pathogenic Bacteria.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {12}, pages = {}, pmid = {34959736}, issn = {1424-8247}, support = {TURSP-2020/262//Taif University/ ; }, abstract = {Gold nanoparticles have gained interest in biomedical sciences in the areas of nano-diagnostics, bio-labeling, drug delivery, and bacterial infection. In this study, we examined, for the first time, the antibacterial and antibiofilm properties of plasmonic gold nanoprisms against human pathogenic bacteria using MIC and crystal violet. In addition, the expression level of GroEL/GroES heat shock proteins was also investigated by western blot. Gold nanoparticles were characterized by TEM and EDX, which showed equilateral triangular prisms with an average edge length of 150 nm. Antibacterial activity testing showed a great effect of AuNPs against pathogenic bacteria with MICs values ranging from 50 μg/mL to 100 μg/mL. Nanoparticles demonstrated strong biofilm inhibition action with a percentage of inhibition ranging from 40.44 to 82.43%. Western blot analysis revealed that GroEL was an AuNPs-inducible protein with an increase of up to 66.04%, but GroES was down-regulated with a reduction of up to 46.81%. Accordingly, plasmonic gold nanoprisms, could be a good candidate for antibiotics substitution in order to treat bacterial infections.}, } @article {pmid34959528, year = {2021}, author = {Al-Dulaimi, M and Algburi, A and Abdelhameed, A and Mazanko, MS and Rudoy, DV and Ermakov, AM and Chikindas, ML}, title = {Antimicrobial and Anti-Biofilm Activity of Polymyxin E Alone and in Combination with Probiotic Strains of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 against Clinical Isolates of Selected Acinetobacter spp.: A Preliminary Study.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34959528}, issn = {2076-0817}, support = {MK-1700.2021.5, agreement № 075-15-2021-179//The Russian Federation President Grant for Young Scientists/ ; }, abstract = {Acinetobacter spp., the nosocomial pathogen, forms strong biofilms and is resistant to numerous antibiotics, causing persistent infections. This study investigates the antibacterial and anti-biofilm activity of polymyxin E alone and in combination with the cell-free supernatants (CFS) of the tested probiotic bacilli, Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 against the selected Acinetobacter spp. starins. Three isolates of Acinetobacter spp., designated as Acinetobacter spp. isolate 1; Acinetobacter spp. isolate 2, and Acinetobacter spp. isolate 3, were collected from patients with burns, wounds, and blood infections, respectively. Bacterial identification and antibiotic susceptibility testing were conducted using the VITEK2 system. Auto-aggregation and coaggregation of the tested bacilli strains with the selected Acinetobacter spp. isolates were evaluated. A disk diffusion assay was used to identify the microorganism's susceptibility to the selected antibiotics, alone and in combination with the CFS of the bacilli. The MIC and MBIC (minimum inhibitory and minimum biofilm inhibitory concentrations) of polymyxin E combined with bacilli CFS were determined. Acinetobacter spp. isolates were (i) sensitive to polymyxin E, (ii) able to form a strong biofilm, and (iii) resistant to the tested antibiotics and the CFS of tested bacilli. Significant inhibition of biofilm formation was noticed when CFS of the tested bacilli were combined with polymyxin E. The bacilli CFS showed synergy with polymyxin E against planktonic cells and biofilms of the isolated pathogens.}, } @article {pmid34959457, year = {2021}, author = {Faleye, OS and Sathiyamoorthi, E and Lee, JH and Lee, J}, title = {Inhibitory Effects of Cinnamaldehyde Derivatives on Biofilm Formation and Virulence Factors in Vibrio Species.}, journal = {Pharmaceutics}, volume = {13}, number = {12}, pages = {}, pmid = {34959457}, issn = {1999-4923}, support = {2021R1I1A3A04037486//National Research Foundation of Korea/ ; 2021R1A2C1008368//National Research Foundation of Korea/ ; 2014R1A6A1031189//National Research Foundation of Korea/ ; }, abstract = {Vibrio parahaemolyticus is considered one of the most relevant pathogenic marine bacteria with a range of virulence factors to establish food-related gastrointestinal infections in humans. Cinnamaldehyde (CNMA) and some of its derivatives have antimicrobial and antivirulence activities against several bacterial pathogens. This study examined the inhibitory effects of CNMA and its derivatives on biofilm formation and the virulence factors in Vibrio species, particularly V. parahaemolyticus. CNMA and ten of its derivatives were initially screened against V. parahaemolyticus biofilm formation, and their effects on the production of virulence factors and gene expression were studied. Among the CNMA derivatives tested, 4-nitrocinnamaldehyde, 4-chlorocinnamaldehyde, and 4-bromocinnamaldehyde displayed antibacterial and antivirulence activities, while the backbone CNMA had weak effects. The derivatives could prevent the adhesion of V. parahaemolyticus to surfaces by the dose-dependent inhibition of cell surface hydrophobicity, fimbriae production, and flagella-mediated swimming and swarming phenotypes. They also decreased the protease secretion required for virulence and indole production, which could act as an important signal molecule. The expression of QS and biofilm-related genes (aphA, cpsA, luxS, and opaR), virulence genes (fliA, tdh, and vopS), and membrane integrity genes (fadL, and nusA) were downregulated in V. parahaemolyticus by these three CNMA analogs. Interestingly, they eliminated V. parahaemolyticus and reduced the background flora from the squid surface. In addition, they exhibited similar antimicrobial and antibiofilm activities against Vibrio harveyi. This study identified CNMA derivatives as potential broad-spectrum antimicrobial agents to treat biofilm-mediated Vibrio infections and for surface disinfection in food processing facilities.}, } @article {pmid34959065, year = {2022}, author = {Liu, XY and Guo, S and Bocklitz, T and Rösch, P and Popp, J and Yu, HQ}, title = {Nondestructive 3D imaging and quantification of hydrated biofilm matrix by confocal Raman microscopy coupled with non-negative matrix factorization.}, journal = {Water research}, volume = {210}, number = {}, pages = {117973}, doi = {10.1016/j.watres.2021.117973}, pmid = {34959065}, issn = {1879-2448}, mesh = {Biofilms ; *Extracellular Polymeric Substance Matrix ; *Imaging, Three-Dimensional ; Microscopy, Confocal ; Pseudomonas aeruginosa ; }, abstract = {Biofilms are ubiquitous in natural and engineered environments and of great importance in drinking water distribution and biological wastewater treatment systems. Simultaneously acquiring the chemical and structural information of the hydrated biofilm matrix is essential for the cognition and regulation of biofilms in the environmental field. However, the complexity of samples and the limited approaches prevent a holistic understanding of the biofilm matrix. In this work, an approach based on the confocal Raman mapping technique integrated with non-negative matrix factorization (NMF) analysis was developed to probe the hydrated biofilm matrix in situ. The flexibility of the NMF analysis was utilized to subtract the undesired water background signal and resolve the meaningful biological components from Raman spectra of the hydrated biofilms. Diverse chemical components such as proteins, bacterial cells, glycolipids and polyhydroxyalkanoates (PHA) were unraveled within the distinct Pseudomonas spp. biofilm matrices, and the corresponding 3-dimensional spatial organization was visualized and quantified. Of these components, glycolipids and PHA were unique to the P. aeruginosa and P. putida biofilm matrix, respectively. Furthermore, their high abundances in the lower region of the biofilm matrix were found to be related to the specific physiological functions and surrounding microenvironments. Overall, the results demonstrate that our NMF Raman mapping method could serve as a powerful tool complementary to the conventional approaches for identifying and visualizing the chemical components in the biofilm matrix. This work may facilitate the online characterization of the biofilm matrix widely present in the environment and advance the fundamental understanding of biofilm.}, } @article {pmid34959064, year = {2022}, author = {Zhuang, JL and Sun, X and Zhao, WQ and Zhang, X and Zhou, JJ and Ni, BJ and Liu, YD and Shapleigh, JP and Li, W}, title = {The anammox coupled partial-denitrification process in an integrated granular sludge and fixed-biofilm reactor developed for mainstream wastewater treatment: Performance and community structure.}, journal = {Water research}, volume = {210}, number = {}, pages = {117964}, doi = {10.1016/j.watres.2021.117964}, pmid = {34959064}, issn = {1879-2448}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Denitrification ; Oxidation-Reduction ; Planctomycetes ; *Sewage ; *Wastewater ; }, abstract = {This study describes an integrated granular sludge and fixed-biofilm (iGB) reactor innovatively designed to carry out the anammox/partial-denitrification (A/PD) process for nitrogen removal with mainstream municipal wastewater. The iGB-A/PD reactor consists of anammox granules inoculated in the lower region of reactor and an acclimated fixed-biofilm positioned in the upper region. Compared to the other reported A/PD systems for mainstream wastewater treatment, this iGB-A/PD reactor is notable due to its higher quality effluent with a total inorganic nitrogen (TIN) of ∼3 mg•L[-1] and operation at a high nitrogen removal rate (NRR) of 0.8 ± 0.1 kg-N•m[-3]•d[-1]. Reads-based metatranscriptomic analysis found that the expression values of hzsA and hdh, key genes associated with anammox, were much higher than other functional genes on nitrogen conversion, confirming the major roles of the anammox bacteria in nitrogen bio-removal. In both regions of the reactor, the nitrate reduction genes (napA/narG) had expression values of 56-99 RPM, which were similar to that of the nitrite reduction genes (nirS/nirK). The expression reads from genes for dissimilatory nitrate reduction to ammonium (DNRA), nrfA and nirB, were unexpectedly high, and were over the half of the levels of reads from genes required for nitrate reduction. Kinetic assays confirmed that the granules had an anammox activity of 16.2 g-NH4[+]-N•kg[-1]-VSS•d[-1] and a nitrate reduction activity of 4.1 g-N•kg[-1]-VSS•d[-1]. While these values were changed to be 4.9 g- NH4[+]-N•kg[-1]-VSS•d[-1]and 4.3 g-N•kg[-1]-VSS•d[-1] respectively in the fixed-biofilm. Mass flux determination found that PD and DNRA was responsible for ∼50% and ∼25% of nitrate reduction, respectively, in the whole reactor, consistent with high effluent quality and treatment efficiency via a nitrite loop. Metagenomic binning analysis revealed that new and unidentified anammox species, affiliated with Candidatus Brocadia, were the dominant anammox organisms. Myxococcota and Planctomycetota were the principal organisms associated with the PD and DNRA processes, respectively.}, } @article {pmid34958948, year = {2022}, author = {Piotrowski, M and Wultańska, D and Pituch, H}, title = {The prebiotic effect of human milk oligosaccharides 3'- and 6'-sialyllactose on adhesion and biofilm formation by Clostridioides difficile - pilot study.}, journal = {Microbes and infection}, volume = {24}, number = {3}, pages = {104929}, doi = {10.1016/j.micinf.2021.104929}, pmid = {34958948}, issn = {1769-714X}, mesh = {*Bacterial Adhesion ; Biofilms ; *Clostridioides ; *Clostridioides difficile ; Humans ; Lactose/analogs & derivatives ; Milk, Human/chemistry ; Oligosaccharides/pharmacology ; Pilot Projects ; Prebiotics/analysis ; }, abstract = {Bacterial adhesion is the first stage of colonisation and biofilm formation by Clostridioides difficile. Cell wall proteins (Cwp) 84 and 66 play crucial roles in the pathophysiology of C. difficile and may affect bacterial adhesion. Sialylated human milk oligosaccharides (HMOs) have potential to inhibit bacterial adhesion in vitro. The aim of this study was to investigate how 3'-sialyllactose (SL) and 6'-SL affect adhesion and C. difficile biofilm formation. Also, the influence of these substances on cwp84 and cwp66 genes expression by C. difficile was assessed. An adhesion assay was performed using three human colon cells in vitro, and biofilm formation was evaluated using crystal violet staining and confocal laser scanning microscopy. The effect of 3'-SL and 6'SL on cwp expression was measured using real time-PCR. Both tested HMOs decreased expression of the cwp84 gene, adhesion of C. difficile to human colon cells in vitro and biofilm formation.}, } @article {pmid34957300, year = {2021}, author = {Ghanizadeh, A and Najafizade, M and Rashki, S and Marzhoseyni, Z and Motallebi, M}, title = {Genetic Diversity, Antimicrobial Resistance Pattern, and Biofilm Formation in Klebsiella pneumoniae Isolated from Patients with Coronavirus Disease 2019 (COVID-19) and Ventilator-Associated Pneumonia.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {2347872}, pmid = {34957300}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; COVID-19/*microbiology/virology ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial/*genetics ; Genetic Variation/*genetics ; Humans ; Intensive Care Units ; Iran ; Klebsiella Infections/drug therapy/*microbiology ; Klebsiella pneumoniae/drug effects/*genetics ; Microbial Sensitivity Tests/methods ; Pandemics/prevention & control ; Pneumonia, Ventilator-Associated/*microbiology/virology ; }, abstract = {INTRODUCTION: Patients with acute respiratory distress syndrome caused by coronavirus disease 2019 (COVID-19) are at risk for superadded infections, especially infections caused by multidrug resistant (MDR) pathogens. Before the COVID-19 pandemic, the prevalence of MDR infections, including infections caused by MDR Klebsiella pneumoniae (K. pneumoniae), was very high in Iran. This study is aimed at assessing the genetic diversity, antimicrobial resistance pattern, and biofilm formation in K. pneumoniae isolates obtained from patients with COVID-19 and ventilator-associated pneumonia (VAP) hospitalized in an intensive care unit (ICU) in Iran.

METHODS: In this cross-sectional study, seventy K. pneumoniae isolates were obtained from seventy patients with COVID-19 hospitalized in the ICU of Shahid Beheshti hospital, Kashan, Iran, from May to September, 2020. K. pneumoniae was detected through the ureD gene. Antimicrobial susceptibility testing was done using the Kirby-Bauer disc diffusion method, and biofilm was detected using the microtiter plate assay method. Genetic diversity was also analyzed through polymerase chain reaction based on enterobacterial repetitive intergenic consensus (ERIC-PCR). The BioNumerics software (v. 8.0, Applied Maths, Belgium) was used for analyzing the data and drawing dendrogram and minimum spanning tree. Findings. K. pneumoniae isolates had varying levels of resistance to antibiotics meropenem (80.4%), cefepime-aztreonam-piperacillin/tazobactam (70%), tobramycin (61.4%), ciprofloxacin (57.7%), gentamicin (55.7%), and imipenem (50%). Around 77.14% of isolates were MDR, and 42.8% of them formed biofilm. Genetic diversity analysis revealed 28 genotypes (E1-E28) and 74.28% of isolates were grouped into ten clusters (i.e., clusters A-J). Clusters were further categorized into three major clusters, i.e., clusters E, H, and J. Antimicrobial resistance to meropenem, tobramycin, gentamicin, and ciprofloxacin in cluster J was significantly higher than cluster H, denoting significant relationship between ERIC clusters and antimicrobial resistance. However, there was no significant difference among major clusters E, H, and J respecting biofilm formation.

CONCLUSION: K. pneumoniae isolates obtained from patients with COVID-19 have high antimicrobial resistance, and 44.2% of them have genetic similarity and can be clustered in three major clusters. There is a significant difference among clusters respecting antimicrobial resistance.}, } @article {pmid34956152, year = {2021}, author = {Lin, YC and Wu, CY and Huang, HT and Lu, MK and Hu, WS and Lee, KT}, title = {Bacillus subtilis natto Derivatives Inhibit Enterococcal Biofilm Formation via Restructuring of the Cell Envelope.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {785351}, pmid = {34956152}, issn = {1664-302X}, abstract = {Enterococcus faecalis is considered a leading cause of hospital-acquired infections. Treatment of these infections has become a major challenge for clinicians because some E. faecalis strains are resistant to multiple clinically used antibiotics. Moreover, the presence of E. faecalis biofilms can make infections with E. faecalis more difficult to eradicate with current antibiotic therapies. Thus, our aim in this study was to investigate the effects of probiotic derivatives against E. faecalis biofilm formation. Bacillus subtilis natto is a probiotic strain isolated from Japanese fermented soybean foods, and its culture fluid potently inhibited adherence to Caco-2 cell monolayers, aggregation, and biofilm production without inhibiting the growth of E. faecalis. An apparent decrease in the thickness of E. faecalis biofilms was observed through confocal laser scanning microscopy. In addition, exopolysaccharide synthesis in E. faecalis biofilms was reduced by B. subtilis natto culture fluid treatment. Carbohydrate composition analysis also showed that carbohydrates in the E. faecalis cell envelope were restructured. Furthermore, transcriptome sequencing revealed that the culture fluid of B. subtilis natto downregulated the transcription of genes involved in the WalK/WalR two-component system, peptidoglycan biosynthesis and membrane glycolipid biosynthesis, which are all crucial for E. faecalis cell envelope synthesis and biofilm formation. Collectively, our work shows that some derivatives present in the culture fluid of B. subtilis natto may be useful for controlling E. faecalis biofilms.}, } @article {pmid34956122, year = {2021}, author = {Kosina, SM and Rademacher, P and Wetmore, KM and de Raad, M and Zemla, M and Zane, GM and Zulovich, JJ and Chakraborty, R and Bowen, BP and Wall, JD and Auer, M and Arkin, AP and Deutschbauer, AM and Northen, TR}, title = {Biofilm Interaction Mapping and Analysis (BIMA) of Interspecific Interactions in Pseudomonas Co-culture Biofilms.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {757856}, pmid = {34956122}, issn = {1664-302X}, abstract = {Pseudomonas species are ubiquitous in nature and include numerous medically, agriculturally and technologically beneficial strains of which the interspecific interactions are of great interest for biotechnologies. Specifically, co-cultures containing Pseudomonas stutzeri have been used for bioremediation, biocontrol, aquaculture management and wastewater denitrification. Furthermore, the use of P. stutzeri biofilms, in combination with consortia-based approaches, may offer advantages for these processes. Understanding the interspecific interaction within biofilm co-cultures or consortia provides a means for improvement of current technologies. However, the investigation of biofilm-based consortia has been limited. We present an adaptable and scalable method for the analysis of macroscopic interactions (colony morphology, inhibition, and invasion) between colony-forming bacterial strains using an automated printing method followed by analysis of the genes and metabolites involved in the interactions. Using Biofilm Interaction Mapping and Analysis (BIMA), these interactions were investigated between P. stutzeri strain RCH2, a denitrifier isolated from chromium (VI) contaminated soil, and 13 other species of pseudomonas isolated from non-contaminated soil. One interaction partner, Pseudomonas fluorescens N1B4 was selected for mutant fitness profiling of a DNA-barcoded mutant library; with this approach four genes of importance were identified and the effects on interactions were evaluated with deletion mutants and mass spectrometry based metabolomics.}, } @article {pmid34955219, year = {2022}, author = {Yang, W and Shan, J and Pan, Y and Bi, Z and Huang, Y and Zhang, H and Ni, M}, title = {A new strategy for obtaining highly concentrated phosphorus recovery solution in biofilm phosphorus recovery process.}, journal = {Journal of environmental sciences (China)}, volume = {112}, number = {}, pages = {366-375}, doi = {10.1016/j.jes.2021.05.017}, pmid = {34955219}, issn = {1001-0742}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; *Phosphorus/analysis ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Recovery of phosphorus (P) from wastewater is of great significance for alleviating the shortage of P resources. At present, the P recovery process is faced with the problem of excessive organic carbon consumption when obtaining a P-concentrated recovery solution. This study proposed a new strategy to obtain a more highly concentrated P recovery solution with minimal carbon consumption by strengthening the P storage capacity of the biofilm. A biofilm sequencing batch reactor (BSBR) process was modified to treat synthetic wastewater. The effect of the dissolved oxygen (DO) concentration on the P storage capacity of the biofilm was investigated at DO concentrations of DO 3.5 mg/L (PL) and DO 6.5 mg/L (PH). The results showed a maximum P storage of 101.2 and 149.6 mg-P/g-mixed liquid suspended solids under the two conditions. Strengthening the P storage capacity of the biofilm resulted in a net increase in the P recovery rate, which was as high as 66.96% in a harvesting cycle, and total soluble P>220 mg/L in the P recovery solution was successfully achieved. Meanwhile, the carbon cost of P recovery in the BSBR was reduced to 41.57 g-chemical oxygen demand/g-P, and the carbon utilization efficiency was enhanced. To highlight the new strategy, the P recovery performance of the BSBR was given and the relationship between P content and anaerobic P release was discussed. In addition, the changes in the microbial communities under PL and PH conditions were analyzed.}, } @article {pmid34954434, year = {2022}, author = {Samak, NA and Selim, MS and Hao, Z and Xing, J}, title = {Immobilized arginine/tryptophan-rich cyclic dodecapeptide on reduced graphene oxide anchored with manganese dioxide for microbial biofilm eradication.}, journal = {Journal of hazardous materials}, volume = {426}, number = {}, pages = {128035}, doi = {10.1016/j.jhazmat.2021.128035}, pmid = {34954434}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Peptides ; Arginine ; Biofilms ; Graphite ; *Manganese Compounds ; Microbial Sensitivity Tests ; *Oxides ; Pseudomonas aeruginosa ; Tryptophan ; }, abstract = {To avoid the accumulation of bacterial biofilms in water pipelines, it is critical to develop potent antimicrobial agents with good ability to reduce extracellular polymeric substances (EPS). In this study, cyclic dodecapeptides were synthesized, and different mutations for increasing the ratio of arginine (Arg) and tryptophan (Trp) were introduced. Separately, the synthesized dodecapeptides were immobilized on a reduced graphene oxide nanocomposite anchored with a hierarchical β-MnO2 (RGO/β-MnO2) hybrid. With a minimum inhibitory concentration of 0.97 g/mL, the immobilized Arg-Trp rich antimicrobial peptides (AMP) on RGO/MnO2 nanocomposite, Cdp-4/RGO/MnO2, showed superior efficacy against multidrug-resistant Pseudomonas aeruginosa ATCC 15692 (P. aeruginosa) planktonic cells. The immobilized Cdp-4/RGO/β-MnO2 also eradicated the mature biofilm by 99% with a minimum inhibitory concentration value of 62.5 µg/mL with significant reduction of EPS. These characteristics allow the use of the immobilized Arg-Trp rich AMP as a promising antimicrobial agent against microbial biofilms, present in water distribution systems.}, } @article {pmid34954415, year = {2022}, author = {Laulund, AS and Schwartz, FA and Christophersen, L and Høiby, N and Svendsen, JSM and Stensen, W and Thomsen, K and Cavanagh, JP and Moser, C}, title = {Lactoferricin-inspired peptide AMC-109 augments the effect of ciprofloxacin against Pseudomonas aeruginosa biofilm in chronic murine wounds.}, journal = {Journal of global antimicrobial resistance}, volume = {29}, number = {}, pages = {185-193}, doi = {10.1016/j.jgar.2021.12.015}, pmid = {34954415}, issn = {2213-7173}, mesh = {Animals ; Biofilms ; Ciprofloxacin/pharmacology/therapeutic use ; Mice ; Mice, Inbred BALB C ; Peptides/pharmacology ; *Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa ; *Wound Infection/drug therapy/microbiology ; }, abstract = {OBJECTIVES: Chronic wounds are characterised by prolonged inflammation, low mitogenic activity, high protease/low inhibitor activity, microbiota changes and biofilm formation, combined with the aetiology of the original insult. One strategy to promote healing is to terminate the parasitism-like relationship between the biofilm-growing pathogen and host response. Antimicrobial peptide AMC-109 is a potential treatment with low resistance potential and broad-spectrum coverage with rapid bactericidal effect. We aimed to investigate whether adjunctive AMC-109 could augment the ciprofloxacin effect in a chronic Pseudomonas aeruginosa wound model.

METHODS: Third-degree burns were inflicted on 33 BALB/c mice. Pseudomonas aeruginosa embedded in seaweed alginate was injected sub-eschar to mimic biofilm. Mice were randomised to receive AMC-109, combined AMC-109 and ciprofloxacin, ciprofloxacin, or placebo for 5 days followed by sample collection.

RESULTS: A lower bacterial load was seen in the double-treated group compared with either monotherapy group (AMC-109, p = 0.0076; ciprofloxacin, p = 0.0266). To evaluate the innate host response, cytokines and growth factors were quantified. The pro-inflammatory response was dampened in the double-treated mice compared with the mono-ciprofloxacin-treated group (p = 0.0009). Lower mobilisation of neutrophils from the bone marrow was indicated by reduced G-CSF in all treatment groups compared with placebo. Improved tissue remodelling was indicated by the highest level of tissue inhibitor of metalloproteases and low metalloprotease level in the double-treated group.

CONCLUSION: AMC-109 showed adjunctive antipseudomonal abilities augmenting the antimicrobial effect of ciprofloxacin in this wound model. The study indicates a potential role for AMC-109 in treating chronic wounds with complicating biofilm infections.}, } @article {pmid34954264, year = {2022}, author = {Oliveira, AS and Rolo, J and Gaspar, C and Cavaleiro, C and Salgueiro, L and Palmeira-de-Oliveira, R and Ferraz, C and Coelho, S and Pastorinho, MR and Sousa, AC and Teixeira, JP and Martinez-de-Oliveira, J and Palmeira-de-Oliveira, A}, title = {Chemical characterization and bioactive potential of Thymus×citriodorus (Pers.) Schreb. preparations for anti-acne applications: Antimicrobial, anti-biofilm, anti-inflammatory and safety profiles.}, journal = {Journal of ethnopharmacology}, volume = {287}, number = {}, pages = {114935}, doi = {10.1016/j.jep.2021.114935}, pmid = {34954264}, issn = {1872-7573}, mesh = {Acne Vulgaris/drug therapy ; Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Anti-Inflammatory Agents/isolation & purification/*pharmacology ; Biofilms/drug effects ; Daphnia ; Mice ; Microbial Sensitivity Tests ; Nitric Oxide/metabolism ; Oils, Volatile/isolation & purification/pharmacology ; Plant Extracts/*pharmacology/toxicity ; Propionibacterium acnes/drug effects ; RAW 264.7 Cells ; Staphylococcus aureus/drug effects ; Staphylococcus epidermidis/drug effects ; Thymus Plant/*chemistry ; Toxicity Tests, Acute ; }, abstract = {Thymus × citriodorus (Pers.) Schreb. is an interspecific hybrid between Thymus pulegioides and Thymus vulgaris, known for its pharmacological activities as diaphoretic, deodorant, antiseptic and disinfectant, the last mostly related with its antimicrobial activity. The folk use of other extracts, as hydrolates, have also been disseminated, as regulators of oily skin with anti-acne effect.

AIM OF THE STUDY: We aimed to evaluate the anti-acne potential of two Thymus x citriodorus (TC) preparations, the essential oil (EO) and the hydrolate, to be used as active ingredients for skin applications. Specifically, we intend to validate their anti-acne potential by describing their activity on acne related bacteria, bacterial virulence, anti-oxidant and anti-inflammatory potential, and biocompatibility on inflammatory cells. Additionally, we aimed to report their ecotoxicity under the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), thus focusing not only on the consumer, but also on environmental safety assessment.

MATERIALS AND METHODS: Minimum inhibitory concentration (MIC) against C. acnes, S. aureus and S. epidermidis was evaluated. Minimum lethal concentration (MLC) was also determined. The effect on C. acnes biofilm formation and disruption was evaluated with crystal violet staining. Anti-inflammatory activity was investigated on LPS-stimulated mouse macrophages (RAW 264.7), by studying nitric oxide (NO) production (Griess reagent) and cellular biocompatibility through MTT assay. In-vitro NO and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging potential were also evaluated. The ecotoxicity was evaluated using Daphnia magna acute toxicity assays.

RESULTS: EO presented direct antimicrobial activity, with visual MICs ranging from 0.06% for S. epidermidis and C. acnes to 0.125% for S. aureus. MLCs were higher than the obtained MICs. Hydrolate revealed visual MIC only for C. acnes. TC essential oil was effective in preventing biofilm formation and disrupting preformed biofilms even at sub-inhibitory concentrations. Hydrolate showed a more modest anti-biofilm effect. Regarding anti-inflammatory activity, TC hydrolate has a higher cellular biocompatibility. Still, both plant preparations were able to inhibit at least 50% of NO production at non-cytotoxic concentrations. Both EO and hydrolate have poor anti-oxidant activities. Regarding the ecotoxicity, TC essential oil was classified under acute 3 category, while the hydrolate has proved to be nontoxic, in accordance to the GHS.

CONCLUSIONS: These results support the anti-acne value of different TC preparations for different applications. TC hydrolate by presenting higher biocompatibility, anti-inflammatory potential and the ability to modulate C. acnes virulence, can be advantageous in a product for everyday application. On the other hand, EO by presenting a marked antimicrobial, anti-biofilm and anti-inflammatory activities, still with some cytotoxicity, may be better suited for application in acute flare-ups, for short treatment periods.}, } @article {pmid34953626, year = {2022}, author = {Siddiqui, DA and Fidai, AB and Natarajan, SG and Rodrigues, DC}, title = {Succession of oral bacterial colonizers on dental implant materials: An in vitro biofilm model.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {38}, number = {2}, pages = {384-396}, pmid = {34953626}, issn = {1879-0097}, support = {R01 DE026736/DE/NIDCR NIH HHS/United States ; }, mesh = {Aggregatibacter actinomycetemcomitans ; Bacterial Adhesion ; Biofilms ; *Dental Implants/microbiology ; Fusobacterium nucleatum/genetics ; *Microbiota ; }, abstract = {OBJECTIVES: Oral bacterial adhesion on dental implant materials has been extensively studied using in vitro systems but has yielded results restricted to in vitro growth patterns due to limitations in species selection, sustained fastidious anaerobe growth, and mixed culture longevity. The aim of this study was to develop an oral bacterial biofilm model consisting of colonizers representative of the oral microbiome exhibiting temporal shifts characteristic of plaque development and maturation in vivo.

METHODS: Streptococcus oralis, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis were grown in monoculture prior to combination in mixed culture. Commercially pure titanium (cpTi) and yttria-stabilized zirconia (ZrO2) disks with polished, acid-etched, or sandblasted surfaces were prepared to evaluate oral bacterial adhesion. After 6 h, 1, 3, 7, 14 and 21 days, genomic DNA from planktonic and adherent bacteria was isolated. Quantitative polymerase chain reaction (qPCR) was used to enumerate the amount and proportion of each species.

RESULTS: Early-colonizing S. oralis and A. actinomycetemcomitans, dominated after 6 h prior to secondary colonization by F. nucleatum and V. parvula in planktonic (1 day) and sessile (3 days) form. A. naeslundii maintained relatively low but stable bacterial counts throughout testing. After 14 days, late-colonizing P. gingivalis became established in mixed culture and persisted, becoming the dominant species after 21 days. The composition of adherent bacteria across all substrates was statistically similar at all timepoints with notable exceptions including lower S. oralis bacterial counts on polished cpTi (3 days).

SIGNIFICANCE: Within the present model's limitations, multispecies oral bacterial attachment is similar on surface-treated cpTi and ZrO2.}, } @article {pmid34953143, year = {2022}, author = {Shi, DL and Shi, H}, title = {The synergistic antibacterial effect and inhibition of biofilm formation of nisin in combination with terpenes against Listeria monocytogenes.}, journal = {Letters in applied microbiology}, volume = {75}, number = {3}, pages = {632-642}, doi = {10.1111/lam.13636}, pmid = {34953143}, issn = {1472-765X}, support = {XDJK2020B043//Fundamental Research Funds for the Central Universities/ ; cx2019017//Venture & Innovation Support Program for Chongqing Overseas Returnees/ ; 32072322//National Natural Science Foundation of China/ ; }, mesh = {Acrolein/analogs & derivatives ; Acyclic Monoterpenes ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cymenes ; *Listeria monocytogenes ; Microbial Sensitivity Tests ; Monoterpenes/pharmacology ; *Nisin/pharmacology ; Stainless Steel ; Terpenes/pharmacology ; Thymol/pharmacology ; }, abstract = {This study was to investigate the synergistic antibacterial effect and inhibition of biofilm formation of nisin in combination with terpenes (carvacrol, cinnamaldehyde, citral and thymol) against Listeria monocytogenes. The bactericidal ranking of terpenes combined with nisin was carvacrol > cinnamaldehyde, citral > thymol. The minimum inhibitory concentration (MIC) of nisin and carvacrol when used together was determined to be 0·1563 mg ml[-1] + 0·0195 mg ml[-1] (nisin at MIC/2 + carvacrol at MIC/16). The addition of nisin at MIC/2 + carvacrol at MIC/2 caused more decrease in membrane potential than carvacrol or nisin at MIC individually. The decrease rates of hlyA and plcA gene expressions caused by nisin at MIC/2 + carvacrol at MIC/2 were significantly higher than those caused by carvacrol or nisin at MIC individually (P < 0·05). Nisin combined with carvacrol showed the highest inhibition activity to the formation of L. monocytogenes biofilm on stainless steel and lettuce. The inhibition effect of nisin at MIC/2 + carvacrol at MIC/16 was significantly higher than that of nisin at MIC/2 and carvacrol at MIC/16 (P < 0·05).}, } @article {pmid34952466, year = {2022}, author = {Mirzaei, R and Ranjbar, R}, title = {Hijacking host components for bacterial biofilm formation: An advanced mechanism.}, journal = {International immunopharmacology}, volume = {103}, number = {}, pages = {108471}, doi = {10.1016/j.intimp.2021.108471}, pmid = {34952466}, issn = {1878-1705}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteria/drug effects/pathogenicity ; *Bacterial Infections/microbiology ; Bacterial Proteins/genetics ; *Biofilms ; *Host Microbial Interactions ; Humans ; Virulence Factors/metabolism ; }, abstract = {Biofilm is a community of bacteria embedded in the extracellular matrix that accounts for 80% of bacterial infections. Biofilm enables bacterial cells to provide particular conditions and produce virulence determinants in response to the unavailability of micronutrients and local oxygen, resulting in their resistance to various antibacterial agents. Besides, the human immune reactions are not completely competent in the elimination of biofilm. Most importantly, the growing body of evidence shows that some bacterial spp. use a variety of mechanisms by which hijack the host components to form biofilm. In this regard, host components, such as DNA, hyaluronan, collagen, fibronectin, mucin, oligosaccharide moieties, filamentous polymers (F-actin), plasma, platelets, keratin, sialic acid, laminin, vitronectin, C3- and C4- binding proteins, antibody, proteases, factor I, factor H, and acidic proline-rich proteins have been reviewed. Hence, the characterization of interactions between bacterial biofilm and the host would be critical to effectively address biofilm-associated infections. In this paper, we review the latest information on the hijacking of host factors by bacteria to form biofilm.}, } @article {pmid34952287, year = {2022}, author = {Nguyen, HT and Hensel, A and Goycoolea, FM}, title = {Chitosan/cyclodextrin surface-adsorbed naringenin-loaded nanocapsules enhance bacterial quorum quenching and anti-biofilm activities.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {211}, number = {}, pages = {112281}, doi = {10.1016/j.colsurfb.2021.112281}, pmid = {34952287}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Caco-2 Cells ; *Chitosan/pharmacology ; *Cyclodextrins/pharmacology ; Escherichia coli ; *Flavanones/pharmacology ; Humans ; *Nanocapsules ; Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {Pathogenic bacteria use quorum sensing (QS), a cell-to-cell communication process that relies on small signaling molecules, to regulate the genetic expression that leads to several essential virulence factors such as bioluminescence, biofilm formation, bacterial motility, among other. Naringenin (NAR), a bitter and colorless flavanone ubiquitous in herbs and fruits, has been shown to inhibit QS activity in P. aeruginosa by decreasing the production of pyocyanin and elastase. In this study, to evaluate the anti-QS activity of naringenin against an E. coli Top 10 biosensor, we developed a novel core-corona nanocapsule formulation comprising surface co-adsorbed β-cyclodextrin (Captisol®) and chitosan loaded with NAR. The results showed that both the nanocapsule (NC) and nanoemulsion (NE) formulations, NAR payload associated with high efficiency , namely ~ 92.88 and ~ 67.98%, respectively. These formulations remained stable for 24 h and showed a biphasic controlled release profile in bacterial M9 medium. Captisol® was effectively immobilized on the NC's surface, resulting in a surface charge inversion from positive (~ + 42 mV) to negative (~ -32 mV) ζ-potential. The biosensor assay revealed that NC outperformed NE in quenching the QS response and the incorporation of naringenin at the NC's multifunctional surface enhanced this bioactivity. Cytotoxicity assays showed that when NAR was associated in NC (188 µM) it was not cytotoxic to Caco2 cells, by contrast with its free form, thus highlighting the cytoprotective effect of the developed formulation. Biofilm formation was inhibited up to ~ 60% in NAR-loaded NC (188 μM), indicating the synergistic effect of positively charged chitosan with the bioactivity of NAR while harnessing the NC's high surface area-to-volume ratio.}, } @article {pmid34952024, year = {2022}, author = {Chen, R and Cao, S and Zhang, L and Zhou, Y}, title = {NOB suppression strategies in a mainstream membrane aerated biofilm reactor under exceptionally low lumen pressure.}, journal = {Chemosphere}, volume = {290}, number = {}, pages = {133386}, doi = {10.1016/j.chemosphere.2021.133386}, pmid = {34952024}, issn = {1879-1298}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Bacteria ; Biofilms ; Bioreactors ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; Sewage ; }, abstract = {Integrating the aeration-efficient membrane aerated biofilm reactor (MABR) with anaerobic ammonium oxidation (anammox) could yield further reduction in energy in wastewater treatment facilities. However, nitrite oxidizing bacteria (NOB) suppression remained challenging due to the absence of intrinsic inhibition factors in mainstream conditions. This study investigated selective NOB suppression strategies in MABR under <5 kPa lumen pressure. Three MABRs were seeded from different seeding sludge, and operated under various ammonium loading rates, aeration pressure, and temporary inhibitory shock conditions. The three reactors were operated for 170-456 days depending on studied parameters. The results showed that higher ammonium loading could create a substrate-oxygen imbalance and quickly contain emergent NOB activity when aeration pressure was not excessive. In addition, lowering of aeration pressure reversed nitrite oxidizing activities without affecting ammonium oxidizing bacteria (AOB). Cultivating partial nitritation biofilm under zero positive aeration pressure slowed down the growth of NOB yet resulted in self-induced anammox activities. With the aid of temporary free ammonia (FA)/free nitrous acid (FNA) treatment, full-nitrifying biofilm could be transformed to stable partial nitritation biofilm. More than 84% nitrite accumulation ratio (NAR) was sustained during stable operation in each reactor together with an ammonium removal rate of more than 100 mg-N/L/d. Microbial analysis revealed that Nitrosomonas was the main AOB taxon in the three reactors while K-strategist Nitrospira showed presence despite low nitrite oxidizing activities. Under zero positive pressure, proliferation of Nitrospira was much slower while Candidatus Brocadia was self-induced. Furthermore, Nitrospira showed downturn after temporary inhibition treatment.}, } @article {pmid34950915, year = {2022}, author = {Wang, S and Sun, P and Zhang, G and Gray, N and Dolfing, J and Esquivel-Elizondo, S and Peñuelas, J and Wu, Y}, title = {Contribution of periphytic biofilm of paddy soils to carbon dioxide fixation and methane emissions.}, journal = {Innovation (Cambridge (Mass.))}, volume = {3}, number = {1}, pages = {100192}, pmid = {34950915}, issn = {2666-6758}, abstract = {Rice paddies are major contributors to anthropogenic greenhouse gas emissions via methane (CH4) flux. The accurate quantification of CH4 emissions from rice paddies remains problematic, in part due to uncertainties and omissions in the contribution of microbial aggregates on the soil surface to carbon fluxes. Herein, we comprehensively evaluated the contribution of one form of microbial aggregates, periphytic biofilm (PB), to carbon dioxide (CO2) and CH4 emissions from paddies distributed across three climatic zones, and quantified the pathways that drive net CH4 production as well as CO2 fixation. We found that PB accounted for 7.1%-38.5% of CH4 emissions and 7.2%-12.7% of CO2 fixation in the rice paddies. During their growth phase, PB fixed CO2 and increased the redox potential, which promoted aerobic CH4 oxidation. During the decay phase, PB degradation reduced redox potential and increased soil organic carbon availability, which promoted methanogenic microbial community growth and metabolism and increased CH4 emissions. Overall, PB acted as a biotic converter of atmospheric CO2 to CH4, and aggravated carbon emissions by up to 2,318 kg CO2 equiv ha[-1] season[-1]. Our results provide proof-of-concept evidence for the discrimination of the contributions of surface microbial aggregates (i.e., PB) from soil microbes, and a profound foundation for the estimation and simulation of carbon fluxes in a potential novel approach to the mitigation of CH4 emissions by manipulating PB growth.}, } @article {pmid34950868, year = {2022}, author = {Coenye, T and Spittaels, KJ and Achermann, Y}, title = {The role of biofilm formation in the pathogenesis and antimicrobial susceptibility of Cutibacterium acnes.}, journal = {Biofilm}, volume = {4}, number = {}, pages = {100063}, pmid = {34950868}, issn = {2590-2075}, abstract = {Cutibacterium acnes (previously known as Propionibacterium acnes) is frequently found on lipid-rich parts of the human skin. While C. acnes is most known for its role in the development and progression of the skin disease acne, it is also involved in many other types of infections, often involving implanted medical devices. C. acnes readily forms biofilms in vitro and there is growing evidence that biofilm formation by this Gram-positive, facultative anaerobic micro-organism plays an important role in vivo and is also involved in treatment failure. In this brief review we present an overview on what is known about C. acnes biofilms (including their role in pathogenesis and reduced susceptibility to antibiotics), discuss model systems that can be used to study these biofilms in vitro and in vivo and give an overview of interspecies interactions occurring in polymicrobial communities containing C. acnes.}, } @article {pmid34949461, year = {2022}, author = {Mazurek-Popczyk, J and Palka, L and Arkusz, K and Dalewski, B and Baldy-Chudzik, K}, title = {Personalized, 3D- printed fracture fixation plates versus commonly used orthopedic implant materials- biomaterials characteristics and bacterial biofilm formation.}, journal = {Injury}, volume = {53}, number = {3}, pages = {938-946}, doi = {10.1016/j.injury.2021.12.020}, pmid = {34949461}, issn = {1879-0267}, mesh = {*Alloys ; Bacteria ; *Biocompatible Materials/chemistry ; Biofilms ; Fracture Fixation ; Humans ; Printing, Three-Dimensional ; Surface Properties ; Titanium/chemistry ; }, abstract = {Additive manufacturing enabled the development of personalized, ideally fitting medical devices. The topography of the surface of the 3D-printed implant may not only facilitate its integration but also cause its rejection, as the surface may become a reservoir for different bacterial strains. In this study, the innovative, raw, 3D- printed fracture fixation plates, manufactured by using selective laser melting (SLM) from Ti-6Al-4V were compared with commercially available, surface-modified plates commonly used in orthopedic surgery. The topography surface of the plates was studied by atomic force microscopy. Susceptibility to the development of biofilm was tested for Staphylococcus epidermidis, Staphylococcus aureus and Streptococcus mutans by using crystal violet staining of biomass, confocal, and scanning electron microscopy (SEM). 3D- printed plates showed higher roughness (Sa=131.0 nm) than commercial plates (CP1 and CP2), Sa= 60.67 nm and Sa=55.48 nm, respectively. All strains of bacteria colonized 3D- printed raw plates more densely than commercial plates. The microscopic visualization showed biofilm mostly in irregular cavities of printed plates while on commercial plates it was mainly located along the edges. The research has indicated that there is need for further development of this technology to optimize its effectiveness and safety.}, } @article {pmid34948803, year = {2021}, author = {Thomas, RE and Thomas, BC}, title = {Reducing Biofilm Infections in Burn Patients' Wounds and Biofilms on Surfaces in Hospitals, Medical Facilities and Medical Equipment to Improve Burn Care: A Systematic Review.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {24}, pages = {}, pmid = {34948803}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents/therapeutic use ; Antimicrobial Peptides ; Biofilms ; *Burns/therapy ; Hospitals ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Pseudomonas aeruginosa ; }, abstract = {Biofilms in burns are major problems: bacterial communities rapidly develop antibiotic resistance, and 60% of burn mortality is attributed to biofilms. Key pathogens are Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and multidrug-resistant Acinetobacter baumanii. Purpose: identify current and novel interventions to reduce biofilms on patients' burns and hospital surfaces and equipment. Medline and Embase were searched without date or language limits, and 31 possible interventions were prioritised: phages, nano-silver, AgSD-NLs@Cur, Acticoat and Mepilex silver, acetic acid, graphene-metal combinations, CuCo2SO4 nanoparticles, Chlorhexidene acetate nanoemulsion, a hydrogel with moxifloxacin, carbomer, Chitosan and Boswellia, LED light therapy with nano-emodin or antimicrobial blue light + Carvacrol to release reactive oxygen species, mannosidase + trypsin, NCK-10 (a napthalene compound with a decyl chain), antimicrobial peptide PV3 (includes two snake venoms), and polypeptides P03 and PL2. Most interventions aimed to penetrate cell membranes and reported significant reductions in biofilms in cfu/mL or biofilm mass or antibiotic minimal inhibitory concentrations or bacterial expression of virulence or quorum sensing genes. Scanning electron microscopy identified important changes in bacterial surfaces. Patients with biofilms need isolating and treating before full admission to hospital. Cleaning and disinfecting needs to include identifying biofilms on keyboards, tablets, cell phones, medical equipment (especially endoscopes), sinks, drains, and kitchens.}, } @article {pmid34947179, year = {2021}, author = {Dadi, NCT and Bujdák, J and Medvecká, V and Pálková, H and Barlog, M and Bujdáková, H}, title = {Surface Characterization and Anti-Biofilm Effectiveness of Hybrid Films of Polyurethane Functionalized with Saponite and Phloxine B.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {24}, pages = {}, pmid = {34947179}, issn = {1996-1944}, support = {1/0227/20//VEGA/ ; 1/0537/19//VEGA/ ; 952398//EU Grant Call: H2020-WIDESPREAD-05-2020 - Twinning/ ; APVV-18-0075//Slovak Research and Development Agency/ ; APVV-19-0487//Slovak Research and Development Agency/ ; SK-PT-18-0006//Slovak Research and Development Agency/ ; }, abstract = {The main objective of this work was to synthesize composites of polyurethane (PU) with organoclays (OC) exhibiting antimicrobial properties. Layered silicate (saponite) was modified with octadecyltrimethylammonium cations (ODTMA) and functionalized with phloxine B (PhB) and used as a filler in the composites. A unique property of composite materials is the increased concentration of modifier particles on the surface of the composite membranes. Materials of different compositions were tested and investigated using physico-chemical methods, such as infrared spectroscopy, X-ray diffraction, contact angle measurements, absorption, and fluorescence spectroscopy in the visible region. The composition of an optimal material was as follows: nODTMA/mSap = 0.8 mmol g[-1] and nPhB/mSap = 0.1 mmol g[-1]. Only about 1.5% of present PhB was released in a cultivation medium for bacteria within 24 h, which proved good stability of the composite. Anti-biofilm properties of the composite membranes were proven in experiments with resistant Staphylococcus aureus. The composites without PhB reduced the biofilm growth 100-fold compared to the control sample (non-modified PU). The composite containing PhB in combination with the photodynamic inactivation (PDI) reduced cell growth by about 10,000-fold, thus proving the significant photosensitizing effect of the membranes. Cell damage was confirmed by scanning electron microscopy. A new method of the synthesis of composite materials presented in this work opens up new possibilities for targeted modification of polymers by focusing on their surfaces. Such composite materials retain the properties of the unmodified polymer inside the matrix and only the surface of the material is changed. Although these unique materials presented in this work are based on PU, the method of surface modification can also be applied to other polymers. Such modified polymers could be useful for various applications in which special surface properties are required, for example, for materials used in medical practice.}, } @article {pmid34946659, year = {2021}, author = {Han, Q and Feng, L and Zhang, Y and Zhang, R and Wang, G and Zhang, Y}, title = {Effect of Juglone against Pseudomonas syringae&nbsp;pv Actinidiae Planktonic Growth and Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {24}, pages = {}, pmid = {34946659}, issn = {1420-3049}, support = {2015NY007//This work was supported by Shaanxi Provincial Agricultural Special Fund Project, Shaanxi Provincial Science and Technology Key Research Project/ ; NC1405 (2).//Xi'an City Science and Technology Planning Project/ ; }, mesh = {Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Naphthoquinones/*pharmacokinetics ; Pseudomonas syringae/*physiology ; }, abstract = {Pseudomonas syringaepv Actinidiae (P. syringae) is a common pathogen causing plant diseases. Limoli proved that its strong pathogenicity is closely related to biofilm state. As a natural bacteriostatic agent with broad-spectrum bactericidal properties, juglone can be used as a substitute for synthetic bacteriostatic agents. To explore the antibacterial mechanism, this study was carried out to examine the inhibitory effect of juglone on cell membrane destruction, abnormal oxidative stress, DNA insertion and biofilm prevention of P. syringae. Results showed that juglone at 20 μg/mL can act against planktogenic P. syringae (10[7] CFU/mL). Specially, the application of juglone significantly damaged the permeability and integrity of the cell membrane of P. syringae. Additionally, juglone caused abnormal intracellular oxidative stress, and also embedded in genomic DNA, which affected the normal function of the DNA of P. syringae. In addition, environmental scanning electron microscope (ESEM) and other methods showed that juglone effectively restricted the production of extracellular polymers, and then affected the formation of the cell membrane. This study provided a possibility for the development and utilization of natural juglone in plants, especially P. syringae.}, } @article {pmid34946212, year = {2021}, author = {Schiffer, CJ and Abele, M and Ehrmann, MA and Vogel, RF}, title = {Bap-Independent Biofilm Formation in Staphylococcus xylosus.}, journal = {Microorganisms}, volume = {9}, number = {12}, pages = {}, pmid = {34946212}, issn = {2076-2607}, support = {AiF 19690N//German Federal Ministry for Economic Affairs and Energy via the German Federation of Industrial Research Associations (AiF) and the Forschungskreis der Ernährungsindustrie E.V. (FEI)/ ; Epic-XS//EU Horizon 2020/ ; }, abstract = {The biofilm associated protein (Bap) is recognised as the essential component for biofilm formation in Staphylococcus aureus V329 and has been predicted as important for other species as well. Although Bap orthologs are also present in most S. xylosus strains, their contribution to biofilm formation has not yet been demonstrated. In this study, different experimental approaches were used to elucidate the effect of Bap on biofilm formation in S. xylosus and the motif structure of two biofilm-forming S. xylosus strains TMW 2.1023 and TMW 2.1523 was compared to Bap of S. aureus V329. We found that despite an identical structural arrangement into four regions, Bap from S. xylosus differs in key factors to Bap of S. aureus, i.e., isoelectric point of aggregation prone Region B, protein homology and type of repeats. Disruption of bap had no effect on aggregation behavior of selected S. xylosus strains and biofilm formation was unaffected (TMW 2.1023) or at best slightly reduced under neutral conditions (TMW 2.1523). Further, we could not observe any typical characteristics of a S. aureus Bap-positive phenotype such as functional impairment by calcium addition and rough colony morphology on congo red agar (CRA). A dominating role of Bap in cell aggregation and biofilm formation as reported mainly for S. aureus V329 was not observed. In contrast, this work demonstrates that functions of S. aureus Bap cannot easily be extrapolated to S. xylosus Bap, which appears as non-essential for biofilm formation in this species. We therefore suggest that biofilm formation in S. xylosus follows different and multifactorial mechanisms.}, } @article {pmid34946178, year = {2021}, author = {Sabbatini, S and Visconti, S and Gentili, M and Lusenti, E and Nunzi, E and Ronchetti, S and Perito, S and Gaziano, R and Monari, C}, title = {Lactobacillus iners Cell-Free Supernatant Enhances Biofilm Formation and Hyphal/Pseudohyphal Growth by Candida albicans Vaginal Isolates.}, journal = {Microorganisms}, volume = {9}, number = {12}, pages = {}, pmid = {34946178}, issn = {2076-2607}, support = {2019-Monari//University of Perugia (Departmental funds for basic research-2019- Monari)/ ; }, abstract = {Candida albicans is a commensal fungus of the vaginal mucosa and the principal etiological agent of vaginal candidiasis. Vaginal dysbiosis has been reported during vulvovaginal candidiasis (VVC), with a progressive decrease in Lactobacillus crispatus population and an increase in L. iners population. To date, the role of L. iners in VVC pathogenesis remains scarcely explored. Herein we investigated the in vitro effect of L. iners cell-free supernatant (CFS) on the ability of C. albicans to form biofilms. Biomass and metabolic activity were measured by crystal violet and XTT assays. Further, light microscopy was performed to determine the effect of L. iners CFS on biofilm cellular morphology. We found that L. iners CFS induced a significant increase in biofilm formation by C. albicans clinical isolates which were categorized as moderate or weak biofilm producers. This effect was associated with an enhancement of hyphal/pseudohyphal growth, and the expression levels of HWP1 and ECE1, which are typical hyphae-associated genes, were upregulated. Overall, these results suggest that L. iners contributes to the pathogenesis of VVC and highlight the complexity of the interaction between C. albicans and vaginal lactobacilli. Understanding these interactions could prove essential for the development of new strategies for treating VVC.}, } @article {pmid34946112, year = {2021}, author = {Ma, Z and Tang, X and Stanford, K and Chen, X and McAllister, TA and Niu, YD}, title = {Single- and Dual-Species Biofilm Formation by Shiga Toxin-Producing Escherichia coli and Salmonella, and Their Susceptibility to an Engineered Peptide WK2.}, journal = {Microorganisms}, volume = {9}, number = {12}, pages = {}, pmid = {34946112}, issn = {2076-2607}, support = {2019C02088//the National Key Research and Development Program of Zhejiang Province/ ; RCP-19-003-MIF//Major Innovation Fund/ ; 32102099//National Natural Science Foundation of China/ ; LQ22C200016//Natural Science Foundation of Zhejiang Province/ ; }, abstract = {Shiga toxin-producing Escherichia coli (STEC) and Salmonella enterica are important foodborne pathogens capable of forming both single- and multi-species biofilms. In this study, the mono- and dual-species biofilms were formed by STEC O113:H21 and Salmonella enterica serovar Choleraesuis 10708 on stainless steel in the presence of beef juice over 5 d at 22 °C. The dual-species biofilm mass was substantially (p < 0.05) greater than that produced by STEC O113:H21 or S. Choleraesuis 10708 alone. However, numbers (CFU/mL) of S. Choleraesuis 10708 or STEC O113:H21 cells in the dual-species biofilm were (p < 0.05) lower than their respective counts in single-species biofilms. In multi-species biofilms, the sensitivity of S. Choleraesuis 10708 to the antimicrobial peptide WK2 was reduced, but it was increased for STEC O113:H21. Visualization of the temporal and spatial development of dual-species biofilms using florescent protein labeling confirmed that WK2 reduced cell numbers within biofilms. Collectively, our results highlight the potential risk of cross-contamination by multi-species biofilms to food safety and suggest that WK2 may be developed as a novel antimicrobial or sanitizer for the control of biofilms on stainless steel.}, } @article {pmid34946068, year = {2021}, author = {Zhang, Y and Lin, Y and Lv, X and Xu, A and Feng, C and Lin, J}, title = {Low-Field Nuclear Magnetic Resonance Characteristics of Biofilm Development Process.}, journal = {Microorganisms}, volume = {9}, number = {12}, pages = {}, pmid = {34946068}, issn = {2076-2607}, abstract = {To in situ and noninvasively monitor the biofilm development process by low-field nuclear magnetic resonance (NMR), experiments should be made to determine the mechanisms responsible for the T2 signals of biofilm growth. In this paper, biofilms were cultivated in both fluid media and saturated porous media. T2 relaxation for each sample was measured to investigate the contribution of the related processes to T2 relaxation signals. In addition, OD values of bacterial cell suspensions were measured to provide the relative number of bacterial cells. We also obtained SEM photos of the biofilms after vacuum freeze-drying the pure sand and the sand with biofilm formation to confirm the space within the biofilm matrix and identify the existence of biofilm formation. The T2 relaxation distribution is strongly dependent on the density of the bacterial cells suspended in the fluid and the stage of biofilm development. The peak time and the peak percentage can be used as indicators of the biofilm growth states.}, } @article {pmid34944398, year = {2021}, author = {Sycz, Z and Tichaczek-Goska, D and Jezierska-Domaradzka, A and Wojnicz, D}, title = {Are Uropathogenic Bacteria Living in Multispecies Biofilm Susceptible to Active Plant Ingredient-Asiatic Acid?.}, journal = {Biomolecules}, volume = {11}, number = {12}, pages = {}, pmid = {34944398}, issn = {2218-273X}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Enterobacter cloacae/drug effects/*growth & development ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Molecular Structure ; Pentacyclic Triterpenes/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/*growth & development ; Urinary Tract Infections/drug therapy/microbiology ; Uropathogenic Escherichia coli/drug effects/*growth & development ; }, abstract = {Urinary tract infections (UTIs) are a serious health problem in the human population due to their chronic and recurrent nature. Bacteria causing UTIs form multispecies biofilms being resistant to the activity of the conventionally used antibiotics. Therefore, compounds of plant origin are currently being searched for, which could constitute an alternative strategy to antibiotic therapy. Our study aimed to determine the activity of asiatic acid (AA) against biofilms formed by uropathogenic Escherichia coli, Enterobacter cloacae, and Pseudomonas aeruginosa. The influence of AA on the survival, biofilm mass formation by bacteria living in mono-, dual-, and triple-species consortia as well as the metabolic activity and bacterial cell morphology were determined. The spectrophotometric methods were used for biofilm mass synthesis and metabolic activity determination. The survival of bacteria was established using the serial dilution assay. The decrease in survival and a weakening of the ability to create biofilms, both single and multi-species, as well as changes in the morphology of bacterial cells were noticed. As AA works best against young biofilms, the use of AA-containing formulations, especially during the initial stages of infection, seems to be reasonable. However, there is a need for further research concerning AA especially regarding its antibacterial mechanisms of action.}, } @article {pmid34944212, year = {2021}, author = {Siddique, A and Azim, S and Ali, A and Adnan, F and Arif, M and Imran, M and Ganda, E and Rahman, A}, title = {Lactobacillus reuteri and Enterococcus faecium from Poultry Gut Reduce Mucin Adhesion and Biofilm Formation of Cephalosporin and Fluoroquinolone-Resistant Salmonella enterica.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {12}, pages = {}, pmid = {34944212}, issn = {2076-2615}, abstract = {Non-typhoidal Salmonella (NTS) can cause infection in poultry, livestock, and humans. Although the use of antimicrobials as feed additives is prohibited, the previous indiscriminate use and poor regulatory oversight in some parts of the world have resulted in increased bacterial resistance to antimicrobials, including cephalosporins and fluoroquinolones, which are among the limited treatment options available against NTS. This study aimed to isolate potential probiotic lactic acid bacteria (LAB) strains from the poultry gut to inhibit fluoroquinolone and cephalosporin resistant MDR Salmonella Typhimurium and S. Enteritidis. The safety profile of the LAB isolates was evaluated for the hemolytic activity, DNase activity, and antibiotic resistance. Based on the safety results, three possible probiotic LAB candidates for in vitro Salmonella control were chosen. Candidate LAB isolates were identified by 16S rDNA sequencing as Lactobacillus reuteri PFS4, Enterococcus faecium PFS13, and Enterococcus faecium PFS14. These strains demonstrated a good tolerance to gastrointestinal-related stresses, including gastric acid, bile, lysozyme, and phenol. In addition, the isolates that were able to auto aggregate had the ability to co-aggregate with MDR S. Typhimurium and S. Enteritidis. Furthermore, LAB strains competitively reduced the adhesion of pathogens to porcine mucin Type III in co-culture studies. The probiotic combination of the selected LAB isolates inhibited the biofilm formation of S. Typhimurium FML15 and S. Enteritidis FML18 by 90% and 92%, respectively. In addition, the cell-free supernatant (CFS) of the LAB culture significantly reduced the growth of Salmonella in vitro. Thus, L. reuteri PFS4, E. faecium PFS13, and E. faecium PFS 14 are potential probiotics that could be used to control MDR S. Typhimurium and S. Enteritidis in poultry. Future investigations are required to elucidate the in vivo potential of these probiotic candidates as Salmonella control agents in poultry and animal feed.}, } @article {pmid34943766, year = {2021}, author = {Wu, S and Zhang, J and Peng, Q and Liu, Y and Lei, L and Zhang, H}, title = {The Role of Staphylococcus aureus YycFG in Gene Regulation, Biofilm Organization and Drug Resistance.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943766}, issn = {2079-6382}, support = {2021YJ0455//Sichuan Provincial Natural Science Foundation of China/ ; 2019YFS0270//Sichuan Provincial Natural Science Foundation of China/ ; 2020HXBH134//Post-Doctor Research Project, West China Hospital, Sichuan University/ ; }, abstract = {Antibiotic resistance is a serious global health concern that may have significant social and financial consequences. Methicillin-resistant Staphylococcus aureus (MRSA) infection is responsible for substantial morbidity and leads to the death of 21.8% of infected patients annually. A lack of novel antibiotics has prompted the exploration of therapies targeting bacterial virulence mechanisms. The two-component signal transduction system (TCS) enables microbial cells to regulate gene expression and the subsequent metabolic processes that occur due to environmental changes. The YycFG TCS in S. aureus is essential for bacterial viability, the regulation of cell membrane metabolism, cell wall synthesis and biofilm formation. However, the role of YycFG-associated biofilm organization in S. aureus antimicrobial drug resistance and gene regulation has not been discussed in detail. We reviewed the main molecules involved in YycFG-associated cell wall biosynthesis, biofilm development and polysaccharide intercellular adhesin (PIA) accumulation. Two YycFG-associated regulatory mechanisms, accessory gene regulator (agr) and staphylococcal accessory regulator (SarA), were also discussed. We highlighted the importance of biofilm formation in the development of antimicrobial drug resistance in S. aureus infections. Data revealed that inhibition of the YycFG pathway reduced PIA production, biofilm formation and bacterial pathogenicity, which provides a potential target for the management of MRSA-induced infections.}, } @article {pmid34943693, year = {2021}, author = {Aguilera-Correa, JJ and Fernández-López, S and Cuñas-Figueroa, ID and Pérez-Rial, S and Alakomi, HL and Nohynek, L and Oksman-Caldentey, KM and Salminen, JP and Esteban, J and Cuadros, J and Puupponen-Pimiä, R and Perez-Tanoira, R and Kinnari, TJ}, title = {Sanguiin H-6 Fractionated from Cloudberry (Rubus chamaemorus) Seeds Can Prevent the Methicillin-Resistant Staphylococcus aureus Biofilm Development during Wound Infection.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943693}, issn = {2079-6382}, abstract = {Staphylococcus aureus is the most common cause of surgical site infections and its treatment is challenging due to the emergence of multi-drug resistant strains such as methicillin-resistant S. aureus (MRSA). Natural berry-derived compounds have shown antimicrobial potential, e.g., ellagitannins such as sanguiin H-6 and lambertianin C, the main phenolic compounds in Rubus seeds, have shown antimicrobial activity. The aim of this study was to evaluate the effect of sanguiin H-6 and lambertianin C fractionated from cloudberry seeds, on the MRSA growth, and as treatment of a MRSA biofilm development in different growth media in vitro and in vivo by using a murine wound infection model where sanguiin H-6 and lambertianin C were used to prevent the MRSA infection. Sanguiin H-6 and lambertianin C inhibited the in vitro biofilm development and growth of MRSA. Furthermore, sanguiin H-6 showed significant anti-MRSA effect in the in vivo wound model. Our study shows the possible use of sanguiin H-6 as a preventive measure in surgical sites to avoid postoperative infections, whilst lambertianin C showed no anti-MRSA activity.}, } @article {pmid34943686, year = {2021}, author = {Martínez, A and Manrique-Moreno, M and Klaiss-Luna, MC and Stashenko, E and Zafra, G and Ortiz, C}, title = {Effect of Essential Oils on Growth Inhibition, Biofilm Formation and Membrane Integrity of Escherichia coli and Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943686}, issn = {2079-6382}, support = {1102-777-57586//Colciencias/ ; 8742//Industrial University of Santander/ ; }, abstract = {Biofilm as a cellular conformation confers survival properties to microbial populations and favors microbial resistance. Here, we investigated the antimicrobial, antibiofilm, antimotility, antihemolytic activity, and the interaction with synthetic membranes of 15 essential oils (EOs) on E. coli ATCC 25922 and S. aureus ATCC 29213. Antimicrobial activity of EOs was determined through microdilution method; development of the biofilm was assessed using the crystal violet assay and SEM microscopy. Results indicate that Lippia origanoides thymol-carvacrol II chemotype (LTC II) and Thymus vulgaris (TV) exhibited a significant antibacterial activity, with MIC values of 0.45 and 0.75 mg/mL, respectively. The percentage of biofilm formation inhibition was greater than 70% at subinhibitory concentrations (MIC50) for LTC II EO. The results demonstrate that these two oils had significantly reduced the hemolytic effect of S. aureus by 54% and 32%, respectively, and the mobility capacity by swimming in E. coli with percentages of decrease of 55% and 47%, respectively. The results show that LTC II and TV EOs can interact with the hydrophobic core of lipid bilayers and alter the physicochemical properties of membranes. The findings suggest that LTC II and TV oils may potentially be used to aid in the treatment of S. aureus and E. coli infections.}, } @article {pmid34943682, year = {2021}, author = {Saeloh, D and Visutthi, M}, title = {Efficacy of Thai Plant Extracts for Antibacterial and Anti-Biofilm Activities against Pathogenic Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943682}, issn = {2079-6382}, abstract = {The emergence of drug-resistant bacteria has impacted the outcome of current therapeutics as a threat to global healthcare; novel medicines are urgently needed. Thirteen medicinal plants were collected in Northeastern Thailand, and their crude ethanolic extracts were evaluated for antibacterial activities against Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922 using the broth micro-dilution method. Piper betle leaf ethanolic extract showed optimal activity against both representative bacterial strains. Activity was also observed against clinical isolates of methicillin-resistant S. aureus (MRSA) and E. coli, with minimal inhibitory concentration (MIC) ranging from 0.31 mg/mL to 2.5 mg/mL and minimal bactericidal concentration (MBC) ranging from 0.62 mg/mL to 2.5 mg/mL. A time-kill study revealed that the extract activity was time- and dose-dependent, and also bactericidal on the tested bacteria. P. betle extract inhibited biofilm formation and promoted biofilm eradication in both S. aureus and E. coli. 4-Allyl-1,2-diacetoxybenzene and eugenol were identified as the most abundant compounds in the extract and may play major roles in the anti-bacterial and anti-biofilm activity. Results suggest that ethanolic P. betle leaf extract shows promise as an alternative method for the prevention of bacterial diseases.}, } @article {pmid34943676, year = {2021}, author = {Wenzler, JS and Krause, F and Böcher, S and Falk, W and Birkenmaier, A and Conrads, G and Braun, A}, title = {Antimicrobial Impact of Different Air-Polishing Powders in a Subgingival Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943676}, issn = {2079-6382}, abstract = {Subgingival air-polishing devices (SAPD) can reduce bacterial biofilms and thus support periodontal healing. The authors of this study evaluated the effectiveness of the glycine-based and trehalose-based air-polishing powders in removing pathogenic bacteria in a subgingival biofilm model. We treated 56 subgingival pockets in porcine jaws with SAPD. Subgingival air polishing was performed in three groups of 13 pockets each: I, glycine-based powder; II, trehalose-based powder; and III, water alone. Another group (IV) served as untreated controls. Prior to air polishing, inoculated titanium bars were inserted into the pockets containing periopathogenic bacteria such as Porphyromonas gingivalis and Tannerella forsythia. Remaining bacteria were evaluated using real-time PCR. The numbers of remaining bacteria depended on the treatment procedure, with the lowest number of total bacteria in group I (median: 1.96 × 10[6] CFU; min: 1.46 × 10[5]; max: 9.30 × 10[6]). Both polishing powders in groups I and II (median: 1.36 × 10[7] CFU; min: 5.22 × 10[5]; max: 7.50 × 10[7]) showed a statistically significantly lower total bacterial load in comparison to both group IV (median: 2.02 × 10[8] CFU; min: 5.14 × 10[7]; max: 4.51 × 10[8]; p < 0.05) and group III (median: 4.58 × 10[7] CFU; min: 2.00 × 10[6]; max: 3.06 × 10[8]; p < 0.05). Both subgingival air-polishing powders investigated can reduce periopathogenic bacteria and thus support antimicrobial therapy approaches in periodontal treatment regimens.}, } @article {pmid34943025, year = {2021}, author = {Cattò, C and Villa, F and Cappitelli, F}, title = {Understanding the Role of the Antioxidant Drug Erdosteine and Its Active Metabolite on Staphylococcus aureus Methicillin Resistant Biofilm Formation.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {34943025}, issn = {2076-3921}, abstract = {Increasing numbers of researches have suggested that some drugs with reactive oxygen species (ROS)-mediated mechanisms of action modulate biofilm formation of some pathogenic strains. However, the full contribution of ROS to biofilm development is still an open question. In this paper, the correlations between the antioxidant drug Erdosteine (Er) and its active Metabolite I (Met I), ROS and biofilm development of two strains of methicillin resistant Staphylococcus aureus are presented. Experiments revealed that Er and Met I at 2 and 5 mg/L increased up to three orders of magnitude the number of biofilm-dwelling cells, while the content of ROS within the biofilms was reduced above the 87%, with a major effect of Met I in comparison to Er. Comparative proteomics showed that, 5 mg/L Met I modified the expression of 30% and 65% of total proteins in the two strains respectively. Some proteins involved in cell replication were upregulated, and a nitric oxide-based mechanism is assumed to modulate the biofilm development by changing quorum sensitive pathways. Additionally, several proteins involved in virulence were downregulated in the presence of Met I, suggesting that treated cells, despite being greater in number, might have lost part of their virulence.}, } @article {pmid34942309, year = {2022}, author = {Demirci, M and Yigin, A and Demir, C}, title = {Efficacy of antimicrobial peptide LL-37 against biofilm forming Staphylococcus aureus strains obtained from chronic wound infections.}, journal = {Microbial pathogenesis}, volume = {162}, number = {}, pages = {105368}, doi = {10.1016/j.micpath.2021.105368}, pmid = {34942309}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Peptides ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections ; Staphylococcus aureus ; *Wound Infection ; }, abstract = {The antimicrobial peptide LL-37 showed inhibitory effects against Staphylococcus aureus strains, which often responsible for wound infections. Understanding the molecular mechanisms of biofilm-containing wound infections is important. Thus, this study aimed to investigate both the antimicrobial and biofilm efficacy of LL-37 against biofilm-positive methicillin-susceptible S. aureus (MSSA) strains and biofilm-positive methicillin-resistant S. aureus (MRSA) strains obtained from chronic wound infections and its effect on different quorum sensing and virulence genes at suboptimal concentrations. Fifteen biofilm-forming MRSA and 15 biofilm-forming MSSA strains were included in this study. The minimum inhibitory concentration (MIC) values and biofilm formation were tested by microdilution methods. Real-time PCR was performed to determine gene expression levels. MIC values for LL-37 were 89.6 mg/L and 132.3 mg/L for MSSA and MRSA strains, respectively. No statistically significant difference was found between MRSA and MSSA strains in terms of the effect of LL-37 on biofilm formation. A statistically significant difference was found between MRSA and MSSA strains for atlA, RNAIII, and agrA gene expression levels following exposure to a suboptimal concentration of LL-37. Ultimately, the required LL-37 antimicrobial concentration was quite high; however, LL-37 antibiofilm concentration may be acceptable for use in humans against biofilm-forming MRSA and MSSA strains. This is the first study to investigate to effect of a suboptimal LL-37 concentration on gene expression levels of biofilm-forming MSSA and MRSA strains. LL-37 affected quorum sensing and biofilm producing mechanisms, even at suboptimal MIC concentrations.}, } @article {pmid34940429, year = {2021}, author = {Javier, L and Pulido-Beltran, L and Kruithof, J and Vrouwenvelder, JS and Farhat, NM}, title = {Phosphorus Concentration in Water Affects the Biofilm Community and the Produced Amount of Extracellular Polymeric Substances in Reverse Osmosis Membrane Systems.}, journal = {Membranes}, volume = {11}, number = {12}, pages = {}, pmid = {34940429}, issn = {2077-0375}, support = {BAS/1/1024-01-01//King Abdullah University of Science and Technology/ ; }, abstract = {Biofouling is a problem that hinders sustainable membrane-based desalination and the stratification of bacterial populations over the biofilm's height is suggested to compromise the efficiency of cleaning strategies. Some studies reported a base biofilm layer attached to the membrane that is harder to remove. Previous research suggested limiting the concentration of phosphorus in the feed water as a biofouling control strategy. However, the existence of bacterial communities growing under phosphorus-limiting conditions and communities remaining after cleaning is unknown. This study analyzes the bacterial communities developed in biofilms grown in membrane fouling simulators (MFSs) supplied with water with three dosed phosphorus conditions at a constant biodegradable carbon concentration. After biofilm development, biofilm was removed using forward flushing (an easy-to-implement and environmentally friendly method) by increasing the crossflow velocity for one hour. We demonstrate that small changes in phosphorus concentration in the feed water led to (i) different microbial compositions and (ii) different bacterial-cells-to-EPS ratios, while (iii) similar bacterial biofilm populations remained after forward flushing, suggesting a homogenous bacterial community composition along the biofilm height. This study represents an exciting advance towards greener desalination by applying non-expensive physical cleaning methods while manipulating feed water nutrient conditions to prolong membrane system performance and enhance membrane cleanability.}, } @article {pmid34940405, year = {2021}, author = {Manandhar, S and Shrestha, R and Tuladhar, RS and Lekhak, S}, title = {Inducible Clindamycin Resistance and Biofilm Production among Staphylococci Isolated from Tertiary Care Hospitals in Nepal.}, journal = {Infectious disease reports}, volume = {13}, number = {4}, pages = {1043-1052}, pmid = {34940405}, issn = {2036-7430}, abstract = {Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLSB. This study aims to find the incidence of different phenotypes of MLSB resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect ica genes. Of the total staphylococci isolates, 161 (42.9%) were Staphylococcus aureus, with 131 (81.4%) methicillin-resistant strains, and 214 (57.1%) isolates were coagulase-negative staphylococci, with 143 (66.8%) methicillin-resistant strains. The overall prevalence of constitutive MLSB (cMLSB) and inducible MLSB (iMLSB) phenotypes was 77 (20.5%) and 87 (23.2%), respectively. Both iMLSB and cMLSB phenotypes predominated in methicillin-resistant isolates. The tissue culture plate method detected biofilm formation in 174 (46.4%) isolates and ica genes in 86 (22.9%) isolates. Among biofilm producing isolates, cMLSB and iMLSB phenotypes were 35 (20.1%) and 27 (15.5%), respectively. The cMLSB and iMLSB were 11 (12.8%) and 19 (22.1%), respectively, in isolates possessing ica genes. Clindamycin resistance in the form of cMLSB and iMLSB, especially among MRSA, emphasizes the need for routine D tests to be performed in the lab.}, } @article {pmid34939783, year = {2022}, author = {Agarwal, S and Kallmyer, NE and Vang, DX and Ramirez, AV and Islam, MM and Hillier, AC and Halverson, LJ and Reuel, NF}, title = {Single-Walled Carbon Nanotube Probes for the Characterization of Biofilm-Degrading Enzymes Demonstrated against Pseudomonas aeruginosa Extracellular Matrices.}, journal = {Analytical chemistry}, volume = {94}, number = {2}, pages = {856-865}, pmid = {34939783}, issn = {1520-6882}, support = {R35 GM138265/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/metabolism ; Biofilms ; Extracellular Matrix/metabolism ; *Nanotubes, Carbon ; *Pseudomonas aeruginosa/metabolism ; }, abstract = {Hydrolase co-therapies that degrade biofilm extracellular polymeric substances (EPS) allow for a better diffusion of antibiotics and more effective treatment; current methods for quantitatively measuring the enzymatic degradation of EPS are not amendable to high-throughput screening. Herein, we present biofilm EPS-functionalized single-walled carbon nanotube (SWCNT) probes for rapid screening of hydrolytic enzyme selectivity and activity on EPS. The extent of biofilm EPS degradation is quantified by monitoring the quenching of the SWCNT fluorescence. We used this platform to screen 16 hydrolases with varying bond breaking selectivity against a panel of wild-type Pseudomonas aeruginosa and mutants deficient or altered in one or more EPS. Next, we performed concentration-dependent studies of six enzymes on two common strains found in cystic fibrosis (CF) environments and, for each enzyme, extracted three first-order rate constants and their relative contributions by fitting a parallel, multi-site degradation model, with a good model fit (R[2] from 0.65 to 0.97). Reaction rates (turnover rates) are dependent on the enzyme concentration and range from 6.67 × 10[-11] to 2.80 × 10[-3] *s[-1] per mg/mL of enzymes. Lastly, we confirmed findings from this new assay using an established crystal-violet staining assay for a subset of hydrolase panels. In summary, our work shows that this modular sensor is amendable to the high-throughput screening of EPS degradation, thereby improving the rate of discovery and development of novel hydrolases.}, } @article {pmid34939033, year = {2021}, author = {Barnes, AMT}, title = {Erratum to "Enterococcus faecalis Colonizes and Forms Persistent Biofilm Microcolonies on Undamaged Endothelial Surfaces in a Rabbit Endovascular Infection Model".}, journal = {FEMS microbes}, volume = {2}, number = {}, pages = {xtab018}, doi = {10.1093/femsmc/xtab018}, pmid = {34939033}, issn = {2633-6685}, abstract = {[This corrects the article DOI: 10.1093/femsmc/xtab014.].}, } @article {pmid34938074, year = {2021}, author = {Fang, JY and Chou, WL and Lin, CF and Sung, CT and Alalaiwe, A and Yang, SC}, title = {Facile Biofilm Penetration of Cationic Liposomes Loaded with DNase I/Proteinase K to Eradicate Cutibacterium acnes for Treating Cutaneous and Catheter Infections.}, journal = {International journal of nanomedicine}, volume = {16}, number = {}, pages = {8121-8138}, pmid = {34938074}, issn = {1178-2013}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; *Biofilms/drug effects ; Catheter-Related Infections/*drug therapy ; Catheters ; Deoxyribonuclease I ; Drug Carriers ; Endopeptidase K ; Liposomes ; Mice ; Propionibacteriaceae/*drug effects ; Skin Diseases, Bacterial/*drug therapy ; Swine ; }, abstract = {BACKGROUND: The biofilm produced by Cutibacterium acnes is a major infection threat for skin and implanted catheters. Nanoparticles provide a new approach to eradicate biofilms. The present study evaluated the capability of cationic liposomes loaded with DNase I (DNS) and proteinase K (PK) to remove preformed C. acnes biofilms.

METHODS: DNS and PK were able to target and disassemble the biofilm by degrading extracellular polymer substances (EPS). Soyaethyl morpholinium ethosulfate (SME) was used to render a positive charge and enhance the antibacterial activity of the liposomes.

RESULTS: The cationic liposomes containing enzymes yielded monodisperse nanovesicles ranging between 95 and 150 nm. The entrapment efficiency of the enzymes in the liposomes achieved a value of 67-83%. All liposomal formulations suppressed planktonic C. acnes growth at a minimum inhibitory concentration (MIC) equal to the free SME in the solution. The enzyme in the liposomal form inhibited biofilm growth much better than that in the free form, with the dual enzyme-loaded liposomes demonstrating the greatest inhibition of 54% based on a crystal violet assay. The biofilm-related virulence genes PA380 and PA1035 were downregulated by the combined enzymes in the liposomes but not the individual DNS or PK. Scanning electron microscopy (SEM) and confocal microscopy displayed reduced C. acnes aggregates and biofilm thickness by the liposomal system. The liposomes could penetrate through about 85% of the biofilm thickness. The in vitro pig skin permeation also showed a facile delivery of liposomes into the epidermis, deeper skin strata, and hair follicles. The liposomes exhibited potent activity to eliminate C. acnes colonization in mouse skin and catheters in vivo. The colony-forming units (CFUs) in the catheter treated with the liposomes were reduced by 2 logs compared to the untreated control.

CONCLUSION: The data suggested a safe application of the enzyme-loaded cationic liposomes as antibacterial and antibiofilm agents.}, } @article {pmid34938036, year = {2021}, author = {Apip, C and Martínez, A and Meléndrez, M and Domínguez, M and Marzialetti, T and Báez, R and Sánchez-Sanhueza, G and Jaramillo, A and Catalán, A}, title = {An in vitro study on the inhibition and ultrastructural alterations of Candida albicans biofilm by zinc oxide nanowires in a PMMA matrix.}, journal = {The Saudi dental journal}, volume = {33}, number = {8}, pages = {944-953}, pmid = {34938036}, issn = {1013-9052}, abstract = {OBJECTIVES: The purpose of this study was (i) to investigate whether nanocomposite poly(methyl-methacrylate)-zinc oxide nanowires (PMMA-ZnO-NWs) have C. albicans antibiofilm activity; (ii) to evaluate the interaction between components of the nanocomposites based on PMMA-ZnO-NWs by Raman spectroscopy; and (iii) to assess ultrastructural alterations.

DESIGN: Sixty-eight rectangles (17 PMMA (control) and 51 PMMA-ZnO-NWs (250, 500, 1000 ppm ZnO nanowires) were fabricated. C. albicans ATCC 10231 and a C. albicans clinical strain were tested. Adherence, biofilm formation and ultrastructural alterations were assessed by transmission electron microscopy. Raman mapping images and spectra were analyzed using main component analysis.

RESULTS: Nanocomposite PMMA-ZnO-NWs inhibited the formation of C. albicans biofilms 94% at 1000 ppm and 80% at 500 ppm against both C. albicans strains. PMMA-ZnO-NWs induced ultrastructural alterations, including cell wall damage and disorganization of the cytoplasmic membrane, resulting in cell lysis. Raman spectroscopy showed new vibrational modes (300-365-485-600 cm[-1]) for PMMA and ZnO-NW interactions.

CONCLUSIONS: PMMA-ZnO-NWs inhibited C. albicans dose-dependent biofilm formation and led to changes in the structures and cell membrane. Raman spectroscopy showed chemical interactions between ZnO-NWs and PMMA, as suggested by the appearance of new bands at 301 and 485 cm[-1].}, } @article {pmid34937434, year = {2022}, author = {Mahto, KU and Kumari, S and Das, S}, title = {Unraveling the complex regulatory networks in biofilm formation in bacteria and relevance of biofilms in environmental remediation.}, journal = {Critical reviews in biochemistry and molecular biology}, volume = {57}, number = {3}, pages = {305-332}, doi = {10.1080/10409238.2021.2015747}, pmid = {34937434}, issn = {1549-7798}, mesh = {Adenosine/metabolism ; Bacteria/metabolism ; *Bacterial Proteins/metabolism ; Biodegradation, Environmental ; Biofilms ; *Environmental Pollutants/metabolism/toxicity ; Gene Expression Regulation, Bacterial ; }, abstract = {Biofilms are assemblages of bacteria embedded within a matrix of extracellular polymeric substances (EPS) attached to a substratum. The process of biofilm formation is a complex phenomenon regulated by the intracellular and intercellular signaling systems. Various secondary messenger molecules such as cyclic dimeric guanosine 3',5'-monophosphate (c-di-GMP), cyclic adenosine 3',5'-monophosphate (cAMP), and cyclic dimeric adenosine 3',5'-monophosphate (c-di-AMP) are involved in complex signaling networks to regulate biofilm development in several bacteria. Moreover, the cell to cell communication system known as Quorum Sensing (QS) also regulates biofilm formation via diverse mechanisms in various bacterial species. Bacteria often switch to the biofilm lifestyle in the presence of toxic pollutants to improve their survivability. Bacteria within a biofilm possess several advantages with regard to the degradation of harmful pollutants, such as increased protection within the biofilm to resist the toxic pollutants, synthesis of extracellular polymeric substances (EPS) that helps in the sequestration of pollutants, elevated catabolic gene expression within the biofilm microenvironment, higher cell density possessing a large pool of genetic resources, adhesion ability to a wide range of substrata, and metabolic heterogeneity. Therefore, a comprehensive account of the various factors regulating biofilm development would provide valuable insights to modulate biofilm formation for improved bioremediation practices. This review summarizes the complex regulatory networks that influence biofilm development in bacteria, with a major focus on the applications of bacterial biofilms for environmental restoration.}, } @article {pmid34936837, year = {2022}, author = {Naik, A and Smithers, M and Moisander, PH}, title = {Impacts of UV-C Irradiation on Marine Biofilm Community Succession.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {4}, pages = {e0229821}, pmid = {34936837}, issn = {1098-5336}, mesh = {Bacteria ; Biofilms ; *Biofouling/prevention & control ; Chlorophyll A ; Humans ; *Seawater/microbiology ; }, abstract = {Marine biofilms are diverse microbial communities and important ecological habitats forming on surfaces submerged in the ocean. Biofilm communities resist environmental disturbance, making them a nuisance to some human activities ("biofouling"). Antifouling solutions rarely address the underlying stability or compositional responses of these biofilms. Using bulk measurements and molecular analyses, we examined temporal and UV-C antifouling-based shifts in marine biofilms in the coastal western North Atlantic Ocean during early fall. Over a 24-day period, bacterial communities shifted from early dominance of Gammaproteobacteria to increased proportions of Alphaproteobacteria, Bacteroidia, and Acidimicrobiia. In a network analysis based on temporal covariance, Rhodobacteraceae (Alphaproteobacteria) nodes were abundant and densely connected with generally positive correlations. In the eukaryotic community, persistent algal, protistan, and invertebrate groups were observed, although consistent temporal succession was not detected. Biofilm UV-C treatment at 13 and 20 days resulted in losses of chlorophyll a and transparent exopolymer particles, indicating biomass disruption. Bacterial community shifts suggested that UV-C treatment decreased the biofilm maturation rate and was associated with proportional shifts among diverse bacterial taxa. UV-C treatment was also associated with increased proportions of protists potentially involved in detritivory and parasitism. Older biofilm communities had increased resistance to UV-C, suggesting that early biofilms are more susceptible to UV-C-based antifouling. The results suggest that UV-C irradiation is potentially an effective antifouling method in marine environments in terms of biomass removal and in slowing maturation. However, as they mature, biofilm communities may accumulate microbial members that are tolerant or resilient under UV treatment. IMPORTANCE Marine biofilms regulate processes ranging from organic matter and pollutant turnover to eukaryotic settlement and growth. Biofilm growth and eukaryotic settlement interfering with human activities via growth on ship hulls, aquaculture operations, or other marine infrastructure are called "biofouling." There is a need to develop sustainable antifouling techniques by minimizing impacts to surrounding biota. We use the biofouling-antifouling framework to test hypotheses about marine biofilm succession and stability in response to disturbance, using a novel UV-C light-emitting diode (LED) device. We demonstrate strong bacterial biofilm successional patterns and detect taxa potentially contributing to stability under UV-C stress. Despite UV-C-associated biomass losses and varying UV susceptibility of microbial taxa, the overall bacterial community composition remained relatively stable, suggesting decoupling of disruption in biomass and community composition following UV-C irradiation. We also report microbial covariance patterns over 24 days of biofilm growth, pointing to areas for study of microbial interactions and targeted antifouling.}, } @article {pmid34935943, year = {2022}, author = {Wang, R and King, DA and Kalchayanand, N}, title = {Evaluation of Salmonella Biofilm Cell Transfer from Common Food Contact Surfaces to Beef Products.}, journal = {Journal of food protection}, volume = {85}, number = {4}, pages = {632-638}, doi = {10.4315/JFP-21-334}, pmid = {34935943}, issn = {1944-9097}, mesh = {Animals ; Biofilms ; Cattle ; Food Microbiology ; Meat/microbiology ; *Salmonella/physiology ; *Salmonella enterica ; Stainless Steel ; }, abstract = {ABSTRACT: Meat contamination by Salmonella enterica is a serious public health concern. Available data have suggested that biofilm formation at processing plants and contaminated contact surfaces might contribute to meat contamination. Because transfer from contact surfaces to food products via direct contact has been deemed the most common bacteria transmission route that can lead to contamination, we evaluated the effect of Salmonella biofilm forming ability, contact surface material, and beef surface tissue type on Salmonella biofilm transfer from hard surfaces to beef products. Salmonella biofilms developed on the common contact surfaces stainless steel (SS) and polyvinylchloride (PVC) were transferred consecutively via 30 s of direct contact to either lean muscle or adipose tissue surfaces of 15 pieces of beef trim. The Salmonella biofilm cells could be effectively transferred multiple times from the contact surfaces to the beef trim as indicated by quantifiable Salmonella cells on most meat samples. Biofilm forming ability had the most significant impact (P < 0.05) on transfer efficiency. More cells of Salmonella strains that formed strong biofilms were transferred after each contact and contaminated more meat samples with quantifiable cells compared with strains that formed weak biofilms. Contact surface materials also affected transferability. Salmonella biofilms on SS transferred more efficiently than did those on PVC. In contrast, the two types of meat surface tissues were not significantly different (P > 0.05) in biofilm transfer efficiency. Beef trim samples that were in contact with biofilms but did not have quantifiable Salmonella cells were positive for Salmonella after enrichment culture. Our results indicate the high potential of Salmonella biofilms on common contact surfaces in meat processing plants to cause product cross-contamination.}, } @article {pmid34935415, year = {2021}, author = {Gélinas, M and Museau, L and Milot, A and Beauregard, PB}, title = {The de novo Purine Biosynthesis Pathway Is the Only Commonly Regulated Cellular Pathway during Biofilm Formation in TSB-Based Medium in Staphylococcus aureus and Enterococcus faecalis.}, journal = {Microbiology spectrum}, volume = {9}, number = {3}, pages = {e0080421}, pmid = {34935415}, issn = {2165-0497}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Biosynthetic Pathways ; Culture Media/chemistry/*metabolism ; Enterococcus faecalis/genetics/*physiology ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Purines/*biosynthesis ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics/*physiology ; }, abstract = {Bacterial biofilms are involved in chronic infections and confer 10 to 1,000 times more resistance to antibiotics compared with planktonic growth, leading to complications and treatment failure. When transitioning from a planktonic lifestyle to biofilms, some Gram-positive bacteria are likely to modulate several cellular pathways, including central carbon metabolism, biosynthesis pathways, and production of secondary metabolites. These metabolic adaptations might play a crucial role in biofilm formation by Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis. Here, we performed a transcriptomic approach to identify cellular pathways that might be similarly regulated during biofilm formation in these bacteria. Different strains and biofilm-inducing media were used to identify a set of regulated genes that are common and independent of the environment or accessory genomes analyzed. Our approach highlighted that the de novo purine biosynthesis pathway was upregulated in biofilms of both species when using a tryptone soy broth-based medium but not so when a brain heart infusion-based medium was used. We did not identify other pathways commonly regulated between both pathogens. Gene deletions and usage of a drug targeting a key enzyme showed the importance of this pathway in biofilm formation of S. aureus. The importance of the de novo purine biosynthesis pathway might reflect an important need for purine during biofilm establishment, and thus could constitute a promising drug target. IMPORTANCE Biofilms are often involved in nosocomial infections and can cause serious chronic infections if not treated properly. Current anti-biofilm strategies rely on antibiotic usage, but they have a limited impact because of the biofilm intrinsic tolerance to drugs. Metabolism remodeling likely plays a central role during biofilm formation. Using comparative transcriptomics of different strains of Staphylococcus aureus and Enterococcus faecalis, we determined that almost all cellular adaptations are not shared between strains and species. Interestingly, we observed that the de novo purine biosynthesis pathway was upregulated during biofilm formation by both species in a specific medium. The requirement for purine could constitute an interesting new anti-biofilm target with a wide spectrum that could also prevent resistance evolution. These results are also relevant to a better understanding of the physiology of biofilm formation.}, } @article {pmid34935196, year = {2022}, author = {Spake, CSL and Berns, EM and Sahakian, L and Turcu, A and Clayton, A and Glasser, J and Barrett, C and Barber, D and Antoci, V and Born, CT and Garcia, DR}, title = {In vitro visualization and quantitative characterization of Pseudomonas aeruginosa biofilm growth dynamics on polyether ether ketone.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {40}, number = {10}, pages = {2448-2456}, doi = {10.1002/jor.25252}, pmid = {34935196}, issn = {1554-527X}, mesh = {Benzophenones ; Biofilms ; Ethers ; *Fluorescent Dyes ; Formaldehyde ; Ketones/pharmacology ; Polymers ; *Pseudomonas aeruginosa ; }, abstract = {Prevention and treatment of orthopedic device-related infection (ODRI) is complicated by the formation of bacterial biofilms. Biofilm formation involves dynamic production of macromolecules that contribute to the structure of the biofilm over time. Limitations to clinically relevant and translational biofilm visualization and measurement hamper advances in this area of research. In this paper, we present a multimodal methodology for improved characterization of Pseudomonas aeruginosa grown on polyether ether ketone (PEEK) as a model for ODRI. PEEK discs were inoculated with P. aeruginosa, incubated for 4-48 h time intervals, and fixed with 10% neutral-buffered formalin. Samples were stained with fluorescent dyes to measure biofilm components, imaged with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and quantified. We were able to visualize and quantify P. aeruginosa biofilm growth on PEEK implants over 48 h. Based on imaging data, we propose a generalized growth cycle that can inform orthopedic diagnostic and treatment for this pathogen on PEEK. These results demonstrate the potential of using a combined CLSM and SEM approach for determining biofilm structure, composition, post-adherence development on orthopedic materials. This model may be used for quantitative biofilm analysis for other pathogens and other materials of orthopedic relevance for translational study of ODRI.}, } @article {pmid34933733, year = {2021}, author = {Ali, FA and Bakir, SH and Haji, SH and Hussen, BM}, title = {Evaluation of blaGES-5 and bla veb-1 genes with multidrug-resistant extend, pandrug resistance patterns (MDR, XDR, PDR), and biofilm formation in Pseudomonas aeruginosa isolates.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {67}, number = {3}, pages = {52-60}, doi = {10.14715/cmb/2021.67.3.7}, pmid = {34933733}, issn = {1165-158X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Base Sequence ; Biofilms/*drug effects/growth & development ; Burns/microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Genotype ; Humans ; Imipenem/pharmacology ; Meropenem/pharmacology ; Microbial Sensitivity Tests/methods ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Sequence Homology, Amino Acid ; beta-Lactamases/*genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous microorganism that is difficult to treat due to the increasing prevalence of multidrug resistance patterns. A total of 227 samples were taken from different clinical samples during the study period from January 2018 to December 2018. The isolates were identified with antibiotic sensitivity testing with ESBL by the Vitek-2 automated method. MDR, XDR, and PDR were determined. 40 (17.6%) isolates were positive for P. aeruginosa, maximum of ESBL and MBL. Positive isolates were detected in the burn, coexisting ESBL + MBL enzymes in 21 (52.5%) of our isolates. Imipenem followed by Meropenem were found to be effective against ESBL and MBL producers. Resistance was reached between 72-100% to 5 antibiotics. The frequency of PDR, MDR, and XDR were 5%, 50%, and 45%, respectively. The frequency of co-production between MDR, XDR, and PDR with MBL, ESBL, and Biofilm was 35%, 12.5% and 5%, respectively. Among the ESBLs, the frequency of distribution of bla VEB-1gene and blaGES-5 gene was 50% and 40 %, respectively. Bacterial isolates simultaneously carrying blaVEB-1 gene with multiple β-lactamases of different classes of biofilm, MDR, PDR, and XDR as same as a coexisting blaGES-5 gene. One isolate was detected as new isolates registered in global gene bank as locally P. aeruginosa isolates in Erbil city (LOCUS MN900953). The phylogenetic trees of the blaVEB gene isolates were demonstrated a genotype closely related to others, deposited in GenBank similar to the P. aeruginosa gene; gene sequencing revealed a 99% similarity with other isolates deposited in GenBank.}, } @article {pmid34933207, year = {2022}, author = {Tremblay, YD and Dupuy, B}, title = {The blueprint for building a biofilm the Clostridioides difficile way.}, journal = {Current opinion in microbiology}, volume = {66}, number = {}, pages = {39-45}, doi = {10.1016/j.mib.2021.12.002}, pmid = {34933207}, issn = {1879-0364}, mesh = {Biofilms ; Clostridioides ; *Clostridioides difficile/genetics ; *Clostridium Infections ; Humans ; }, abstract = {Clostridioides difficile is an opportunistic pathogen that causes by a high rate of recurrent infections. Persistence in the gastrointestinal tract is thought to be mediated by sporulation and/or biofilm formation. There is an increase interest in C. difficile biofilm formation and recent findings have provided a framework to model surface-attached biofilm formation. For in vitro biofilm formation, C. difficile must undergo a metabolic reprogramming as it enters stationary phase. This helps maintain long-term viability and increases responsiveness to signals leading to biofilm formation. Metabolic reprogramming and biofilm formation requires several regulatory factors and these overlap with the sporulation cascade. Despite recent advances, further research is needed to answer outstanding questions in the field.}, } @article {pmid34929524, year = {2022}, author = {Yang, L and Sui, Y and Zhong, L and Ma, T and Ma, Z and Liu, X}, title = {Carnosol inhibits the growth and biofilm of Candida albicans.}, journal = {Journal de mycologie medicale}, volume = {32}, number = {2}, pages = {101234}, doi = {10.1016/j.mycmed.2021.101234}, pmid = {34929524}, issn = {1773-0449}, mesh = {Abietanes ; Antifungal Agents/pharmacology ; *Biofilms ; *Candida albicans ; Hyphae ; Microbial Sensitivity Tests ; Plankton ; }, abstract = {OBJECTIVE: This study was to explore the inhibitory effects of carnosol on the growth and biofilm of Candida albicans.

RESULTS: Our results showed that carnosol inhibited the planktonic growth of C. albicans with a MIC of 100 μg/mL. Carnosol can also inhibit the biofilm formation and development of C. albicans. 25-100 μg/mL of carnosol can obviously inhibit the yeast-to-hyphal transition in four kinds of hyphal-inducing media and the adhesion of C. albicans to polystyrene surfaces. Results from PI staining indicated that carnosol may disrupt cell membrane of C. albicans.

CONCLUSION: Carnosol can inhibit the planktonic growth and virulence factors of C. albicans, such as biofilm formation, adhesion and hyphal growth. The antifungal mechanism may involve the increase in cell membrane permeability.}, } @article {pmid34929185, year = {2022}, author = {Ganesan, S and Ruendee, T and Kimura, SY and Chawengkijwanich, C and Janjaroen, D}, title = {Effect of biofilm formation on different types of plastic shopping bags: Structural and physicochemical properties.}, journal = {Environmental research}, volume = {206}, number = {}, pages = {112542}, doi = {10.1016/j.envres.2021.112542}, pmid = {34929185}, issn = {1096-0953}, mesh = {Bacterial Adhesion ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; *Plastics ; Polyethylene ; Surface Properties ; }, abstract = {Plastics and biofilms have a complicated relationship that has great interest. Bacterial cell attachment and biofilm formation is considered to cause health and environmental risks from plastic waste accumulation. In water, plastic waste could serve as a new substrate for bacteria. In our study, the attachment of Escherichia coli K12, to four types of plastic shopping bags (biodegradable polylactic acid and the non-biodegradable polypropylene, polyethylene and polyvinyl chloride) was investigated. The change in physicochemical phenomena of each plastic, such as reduced hydrophobicity and higher exopolysaccharide concentrations (total extractable protein and carbohydrate) resulted in increased biofilm content on the plastic surfaces. The bacterial colonization of different plastic surfaces controls the ionic strength of the nutrition sources. The adhesion of Escherichia coli K12 cells on the surfaces were revealed by SEM images. The finding shows that increases surface roughness, besides favor for adhesion of bacterial cells due to hydrophobicity leading to a rapid attachment of Escherichia coli K12 on the surfaces. In addition, we used Derjaguin-Landau-Verwey-Overbeek theory to predict the attachment of Escherichia coli K12, which gave result of adhesion due to the high energy barrier. This present study added to our knowledge of the possible consequences of plastics acting as a new habitat for microbes in different aquatic condition.}, } @article {pmid34927785, year = {2022}, author = {Nair, A and Vyawahare, R and Khairnar, K}, title = {Characterization of a novel, biofilm dispersing, lytic bacteriophage against drug-resistant Enterobacter cloacae.}, journal = {Journal of applied microbiology}, volume = {132}, number = {4}, pages = {2721-2732}, doi = {10.1111/jam.15420}, pmid = {34927785}, issn = {1365-2672}, support = {GAP-1-2066//Department of Science and Technology - Science and Engineering Research Board (DST-SERB)/ ; G-2103//National Mission for Clean Ganga-Namami Gange Project/ ; //Council of Scientific and Industrial Research (CSIR)/ ; //Academy of Science and Innovative Research (AcSIR)/ ; }, mesh = {*Bacteriophages/genetics ; Biofilms ; Enterobacter cloacae/genetics ; Genome, Viral ; Sewage ; }, abstract = {AIM: To characterize a novel bacteriophage, En5822, isolated from the environment against Enterobacter cloacae and exploring its application as an alternate antimicrobial.

METHODS AND RESULTS: Bacteriophage was isolated from sewage sample by membrane-filtration immobilization technique. It was purified and studied for its various physical properties like microscopic structure, thermal and pH stability, latent period and burst time, antimicrobial and anti-biofilm activity as well as molecular aspects by genome sequencing and analysis. En5822 is a myovirus with relative pH and thermal stability. En5822 shows a notable reduction of host bacterial biofilm as well as planktonic cultures. Whole genome sequence analysis revealed that the En5822 genome does not contain undesirable temperate lifestyle genes, antibiotic resistance genes and toxin-encoding genes.

CONCLUSIONS: En5822 displays high lytic activity, specificity and biofilm reduction capability. It has a short latent period and high burst size that aid faster activity. Its genomic and physical attributes offer possibilities for its as an alternative antimicrobial for the treatment of drug-resistant E. cloacae infections.

The study describes a novel, naturally virulent bacteriophage from environment capable of lysing multi-drug resistant E. cloacae effectively. The phage could potentially serve as an alternative strategy for treating antibiotic-resistant infections.}, } @article {pmid34926431, year = {2021}, author = {Hu, Y and Wang, Y and Han, X and Shan, Y and Li, F and Shi, L}, title = {Biofilm Biology and Engineering of Geobacter and Shewanella spp. for Energy Applications.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {786416}, pmid = {34926431}, issn = {2296-4185}, abstract = {Geobacter and Shewanella spp. were discovered in late 1980s as dissimilatory metal-reducing microorganisms that can transfer electrons from cytoplasmic respiratory oxidation reactions to external metal-containing minerals. In addition to mineral-based electron acceptors, Geobacter and Shewanella spp. also can transfer electrons to electrodes. The microorganisms that have abilities to transfer electrons to electrodes are known as exoelectrogens. Because of their remarkable abilities of electron transfer, Geobacter and Shewanella spp. have been the two most well studied groups of exoelectrogens. They are widely used in bioelectrochemical systems (BESs) for various biotechnological applications, such as bioelectricity generation via microbial fuel cells. These applications mostly associate with Geobacter and Shewanella biofilms grown on the surfaces of electrodes. Geobacter and Shewanella biofilms are electrically conductive, which is conferred by matrix-associated electroactive components such as c-type cytochromes and electrically conductive nanowires. The thickness and electroactivity of Geobacter and Shewanella biofilms have a significant impact on electron transfer efficiency in BESs. In this review, we first briefly discuss the roles of planktonic and biofilm-forming Geobacter and Shewanella cells in BESs, and then review biofilm biology with the focus on biofilm development, biofilm matrix, heterogeneity in biofilm and signaling regulatory systems mediating formation of Geobacter and Shewanella biofilms. Finally, we discuss strategies of Geobacter and Shewanella biofilm engineering for improving electron transfer efficiency to obtain enhanced BES performance.}, } @article {pmid34925248, year = {2021}, author = {Berini, F and Orlandi, VT and Gamberoni, F and Martegani, E and Armenia, I and Gornati, R and Bernardini, G and Marinelli, F}, title = {Antimicrobial Activity of Nanoconjugated Glycopeptide Antibiotics and Their Effect on Staphylococcus aureus Biofilm.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {657431}, pmid = {34925248}, issn = {1664-302X}, abstract = {In the era of antimicrobial resistance, the use of nanoconjugated antibiotics is regarded as a promising approach for preventing and fighting infections caused by resistant bacteria, including those exacerbated by the formation of difficult-to-treat bacterial biofilms. Thanks to their biocompatibility and magnetic properties, iron oxide nanoparticles (IONPs) are particularly attractive as antibiotic carriers for the targeting therapy. IONPs can direct conjugated antibiotics to infection sites by the use of an external magnet, facilitating tissue penetration and disturbing biofilm formation. As a consequence of antibiotic localization, a decrease in its administration dosage might be possible, reducing the side effects to non-targeted organs and the risk of antibiotic resistance spread in the commensal microbiota. Here, we prepared nanoformulations of the 'last-resort' glycopeptides teicoplanin and vancomycin by conjugating them to IONPs via surface functionalization with (3-aminopropyl) triethoxysilane (APTES). These superparamagnetic NP-TEICO and NP-VANCO were chemically stable and NP-TEICO (better than NP-VANCO) conserved the typical spectrum of antimicrobial activity of glycopeptide antibiotics, being effective against a panel of staphylococci and enterococci, including clinical isolates and resistant strains. By a combination of different methodological approaches, we proved that NP-TEICO and, although to a lesser extent, NP-VANCO were effective in reducing biofilm formation by three methicillin-sensitive or resistant Staphylococcus aureus strains. Moreover, when attracted and concentrated by the action of an external magnet, NP-TEICO exerted a localized inhibitory effect on S. aureus biofilm formation at low antibiotic concentration. Finally, we proved that the conjugation of glycopeptide antibiotics to IONPs reduced their intrinsic cytotoxicity toward a human cell line.}, } @article {pmid34924339, year = {2022}, author = {Horng, YT and Dewi Panjaitan, NS and Chang, HJ and Wei, YH and Chien, CC and Yang, HC and Chang, HY and Soo, PC}, title = {A protein containing the DUF1471 domain regulates biofilm formation and capsule production in Klebsiella pneumoniae.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {55}, number = {6 Pt 2}, pages = {1246-1254}, doi = {10.1016/j.jmii.2021.11.005}, pmid = {34924339}, issn = {1995-9133}, mesh = {Humans ; *Klebsiella pneumoniae/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Biofilms ; Fimbriae, Bacterial/genetics/metabolism ; *Klebsiella Infections/microbiology ; }, abstract = {BACKGROUND/PURPOSE: Biofilms formed by Klebsiella pneumoniae on medical devices increase infection risk. Fimbriae and capsule polysaccharides (CPSs) are important factors involved in biofilm formation. KP1_4563 in K. pneumoniae NTUH-K2044, a small protein containing the DUF1471 domain, was reported to inhibit type 3 fimbriae function. In this study, we aimed to determine whether the KP1_4563 homolog is conserved in each K. pneumoniae isolate and what role it has in Klebsiella biofilms.

METHODS: The genomes of K. pneumoniae NTUH-K2044, CG43, MGH78578, KPPR1 and STU1 were compared. The KP1_4563 homolog in K. pneumoniae STU1 was named orfX. Biofilms of wild-type and orfX mutant strains from K. pneumoniae STU1 and one clinical isolate, 83535, were quantified. Transcription levels of the type 3 fimbrial genes, mrkA and mrkH, were investigated by RT-qPCR. MrkA of the wild-type and orfX mutant were observed by Western blotting. The morphology of bacterial cells was observed by transmission electron microscopy (TEM). Bacterial CPSs were quantified.

RESULTS: The gene and upstream region of orfX were conserved among the five K. pneumoniae isolates. Deletion of orfX enhanced Klebsiella biofilm formation. However, the amount of mRNA from mrkA and mrkH and the level of MrkA protein were not different between the wild type and orfX mutant. In contrast, the amount of CPS in orfX mutants was increased, compared to their parental strains, STU1 and 83535.

CONCLUSION: The role of orfX is speculated to be conserved in most K. pneumoniae isolates. OrfX negatively controlled biofilm formation by reducing CPS, not type 3 fimbriae, production.}, } @article {pmid34923916, year = {2021}, author = {Li, J and Fan, Q and Jin, M and Mao, C and Zhang, H and Zhang, X and Sun, L and Grenier, D and Yi, L and Hou, X and Wang, Y}, title = {Paeoniflorin reduce luxS/AI-2 system-controlled biofilm formation and virulence in Streptococcus suis.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {3062-3073}, pmid = {34923916}, issn = {2150-5608}, mesh = {Animals ; Bacterial Proteins/genetics/pharmacology ; Biofilms ; Carbon-Sulfur Lyases/genetics/pharmacology ; Glucosides ; Homoserine ; Lactones/pharmacology ; Mice ; Molecular Docking Simulation ; Monoterpenes/pharmacology ; Quorum Sensing ; *Streptococcus suis ; Swine ; Virulence ; }, abstract = {Streptococcus suis (S. suis), more specifically serotype 2, is a bacterial pathogen that threatens the lives of pigs and humans. Like many other pathogens, S. suis exhibits quorum sensing (QS) system-controlled virulence factors, such as biofilm formation that complicates treatment. Therefore, impairing the QS involving LuxS/AI-2 cycle in S. suis, may be a promising alternative strategy for overcoming S. suis infections. In this study, we investigated paeoniflorin (PF), a monoterpenoid glycoside compound extracted from peony, as an inhibitor of S. suis LuxS/AI-2 system. At a sub-minimal inhibitory concentration (MIC) (1/16 MIC; 25 μg/ml), PF significantly reduced biofilm formation by S. suis through inhibition of extracellular polysaccharide (EPS) production, without affecting bacterial growth. Moreover, evidence was brought that PF reduces AI-2 activity in S. suis biofilm. Molecular docking indicated that LuxS may be the target of PF. Monitoring LuxS enzymatic activity confirmed that PF had a partial inhibitory effect. Finally, we showed that the use of PF in a mouse model can relieve S. suis infections. This study highlighted the anti-biofilm potential of PF against S. suis, and brought evidence that it may as an inhibitor of the LuxS/AI-2 system to prevent S. suis biofilm-related infections. PF can thus be used as a new type of natural biofilm inhibitor for clinical application.}, } @article {pmid34922103, year = {2021}, author = {Perez, LJ and Parashar, R and Plymale, A and Scheibe, TD}, title = {Contributions of biofilm-induced flow heterogeneities to solute retention and anomalous transport features in porous media.}, journal = {Water research}, volume = {209}, number = {}, pages = {117896}, doi = {10.1016/j.watres.2021.117896}, pmid = {34922103}, issn = {1879-2448}, abstract = {Microbial biofilms are ubiquitous within porous media and the dynamics of their growth influence surface and subsurface flow patterns which impacts the physical properties of porous media and large-scale transport of solutes. A two-dimensional pore-scale numerical model was used to evaluate the impact of biofilm-induced flow heterogeneities on conservative transport. Our study integrates experimental biofilm images of Paenibacillus 300A strain in a microfluidic device packed with cylindrical grains in a hexagonal distribution, with mathematical modeling. Biofilm is represented as a synthetic porous structure with locally varying physical properties that honors the impact of biofilm on the porous medium. We find that biofilm plays a major role in shaping the observed conservative transport dynamics by enhancing anomalous characteristics. More specifically, when biofilm is present, the pore structure in our geometry becomes more spatially correlated. We observe intermittent behavior in the Lagrangian velocities that switches between fast transport periods and long trapping events. Our results suggest that intermittency enhances solute spreading in breakthrough curves which exhibit extreme anomalous slope at intermediate times and very marked late solute arrival due to solute retention. The efficiency of solute retention by the biofilm is controlled by a transport regime which can extend the tailing in the concentration breakthrough curves. These results indicate that solute retention by the biofilm exerts a strong control on conservative solute transport at pore-scale, a role that to date has not received enough attention.}, } @article {pmid34922056, year = {2022}, author = {Zadeh, RG and Kalani, BS and Ari, MM and Talebi, M and Razavi, S and Jazi, FM}, title = {Isolation of persister cells within the biofilm and relative gene expression analysis of type II toxin/antitoxin system in Pseudomonas aeruginosa isolates in exponential and stationary phases.}, journal = {Journal of global antimicrobial resistance}, volume = {28}, number = {}, pages = {30-37}, doi = {10.1016/j.jgar.2021.11.009}, pmid = {34922056}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Antitoxins/genetics/metabolism ; Biofilms ; Ciprofloxacin/pharmacology ; Colistin/pharmacology ; Gene Expression ; Humans ; *Pseudomonas aeruginosa ; }, abstract = {OBJECTIVES: Chronic infections and treatment failure are concerning issues in patients with Pseudomonas aeruginosa infections. Persister cell formation in biofilm is considered a key reason for antibiotic resistance and treatment failure. In this study, expression of type II toxin/antitoxin (TA) system genes (relBE, Xre-COG5654, vapBC and Xre-GNAT) in persister cells of biofilm was evaluated in the presence of the antibiotics ciprofloxacin and colistin during exponential and stationary phases.

METHODS: The impact of antibiotics on biofilm persister cell formation during exponential and stationary phases of P. aeruginosa strains was examined by colony count at different time intervals in the presence of 5-fold minimum inhibitory concentration (MIC) of ciprofloxacin and colistin. Furthermore, expression of relBE, Xre-COG5654, vapBC and Xre-GNAT genes in P. aeruginosa strains undergoing antibiotic treatment for 3.5 h during exponential and stationary phases was examined by RT-qPCR.

RESULTS: Formation of persister cells was observed in biofilms formed by P. aeruginosa strains in the presence of 5 × MIC of ciprofloxacin and colistin compared with the control group after 3.5 h of incubation both during exponential and stationary phases. The number of biofilm persister cells was higher in stationary phase than in exponential phase. According to the findings of RT-qPCR, ciprofloxacin and colistin may induce persister cell formation by enhancing the expression of type II TA systems during stationary and exponential phases.

CONCLUSION: The result of this study indicate that ciprofloxacin and colistin have the potential to increase persister cells formation in biofilms by influencing the expression of type II TA systems.}, } @article {pmid34921987, year = {2022}, author = {Li, Y and Du, J and Huang, S and Wang, S and Wang, Y and Cai, Z and Lei, L and Huang, X}, title = {Hydrogen peroxide potentiates antimicrobial photodynamic therapy in eliminating Candida albicans and Streptococcus mutans dual-species biofilm from denture base.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {37}, number = {}, pages = {102691}, doi = {10.1016/j.pdpdt.2021.102691}, pmid = {34921987}, issn = {1873-1597}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; Candida albicans ; Denture Bases ; Hydrogen Peroxide/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Streptococcus mutans ; }, abstract = {BACKGROUND: Candida albicans (C.albicans) is the primary pathogen of denture biofilm. Moreover, it could establish a cross-kingdom relationship with bacteria to enhance its virulence and resistance to antifungal drugs. This study aimed to investigate the efficacy of antimicrobial photodynamic therapy (aPDT) in combination with hydrogen peroxide (H2O2) against C.albicans and Streptococcus mutans (S.mutans) dual-species biofilm formed on polymethyl methacrylate (PMMA) disk, and explore its involved mechanisms.

METHODS: C.albicans and S.mutans were grown on PMMA disk for 48 h to form biofilm and received different treatments. The treatments included:1) phosphate-buffered saline (PBS) group,2) 100 mM H2O2 group,3) aPDT group,4) aPDT+ H2O2 and 5) H2O2+aPDT group. Colony forming units (CFU), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and scanning electron microscope (SEM) were used to evaluate the antimicrobial effects. Extracellular polysaccharide substance (EPS) production and observation, cell permeability of biofilm, and uptake of toluidine blue O (TBO) by biofilm were assessed to investigate the involved mechanism.

RESULTS: There was no significant difference between PBS group and H2O2 group in viable microorganisms and metabolic activity of biofilm. The treatment protocols containing aPDT group reduced microorganism numbers and metabolic activity when compared to PBS group or H2O2 group (P<0.05). H2O2+aPDT treatment showed the highest antimicrobial efficacy in comparison with other treatments (P<0.05). Pretreatment with H2O2 could decrease EPS production and enhance cell permeability, leading to increased TBO uptake in biofilm.

CONCLUSION: Pretreatment with H2O2 improved aPDT efficiency in eliminating dual-species biofilm from PMMA disk by reducing EPS amount, enhancing cell permeability, and increasing TBO uptake.}, } @article {pmid34921957, year = {2022}, author = {Dawan, J and Ahn, J}, title = {Assessment of phage-mediated control of antibiotic-resistant Salmonella Typhimurium during the transition from planktonic to biofilm cells.}, journal = {Microbial pathogenesis}, volume = {162}, number = {}, pages = {105365}, doi = {10.1016/j.micpath.2021.105365}, pmid = {34921957}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriophages ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Microbial Sensitivity Tests ; Plankton ; *Salmonella typhimurium ; }, abstract = {This study was designed to evaluate the abilities of phage P22 to lyse, eradiate, and disperse the biofilm cells of Salmonella enterica serovar Typhimurium ATCC 19585 (ST[WT]), ciprofloxacin-induced Typhimurium ATCC 19585 (ST[CIP]), S. Typhimurium KCCM 40253 (ST[KCCM]), and multidrug-resistant S. Typhimurium CCARM 8009 (ST[CCARM]) in association with hydrophobicity, auto-aggregation, motility, protein content, extracellular DNA, and depolymerase activity. The affinity to hexadecane was significantly increased in ST[WT], ST[KCCM], and ST[CCARM] cells after P22 infection. All strains tested showed relatively higher auto-aggregation abilities in the presence of P22 than the absence of P22. ST[KCCM] showed the greatest auto-aggregative ability (23%) in the presence of P22, while ST[WT] showed the least auto-aggregative ability (9%) in the absence of P22. The bacterial swimming motility affected the bacterial attachment at the early stage of biofilm formation. The red, dry and rough morphotype was observed for all strains tested. The numbers of ST[WT], ST[CIP], and ST[KCCM] planktonic cells were considerably reduced by 7.2, 5.0, and 5.0 log CFU/ml, respectively, and ST[WT], ST[CIP], and ST[KCCM] biofilm-forming cells were reduced by 5.8, 4.5, and 4.9 log, respectively, after 24 h of phage infection. The depolymerase produced by phages were confirmed by the presence of outer rim of plaques. Phages could be considered as promising alternatives for the control of biofilms due to their advantages including enzymatic degradation of extracellular biofilm matrix. The study would provide useful information for understanding the dynamic interactions between phages and biofilms and also designing the effective phage-based control system as an alterative strategy against biofilms.}, } @article {pmid34921922, year = {2022}, author = {Yang, S and Song, P and Zhuang, B and Zhang, S and Han, X and Peng, Y and Li, J and Zhang, L}, title = {Distinct granulation pathways of anammox granular sludge under biofilm enhancement.}, journal = {Bioresource technology}, volume = {345}, number = {}, pages = {126569}, doi = {10.1016/j.biortech.2021.126569}, pmid = {34921922}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; Nitrogen ; Oxidation-Reduction ; *Sewage ; }, abstract = {The simultaneous partial nitrification and anammox (PN/A) granular sludge process in a plug-flow reactor has been difficult to achieve. This study provides a novel way to enhance granulation using biofilm detachment. In a plug-flow reactor, a fixed carrier was added to the activated sludge, and a PN/A biofilm gradually formed during the operation. Mature biofilm detachment appeared and caused the emergence of micro-granule. Then the fixed carriers were removed from the reactor, but the nitrogen removal rate (NRR) of the reactor was barely affected. This result suggests granular sludge is a feasible replacement for biofilm. Moreover, the particle size of the granule increased from 212 to 425 μm, and the NRR was 1.63 kg N/(m[3]·d), with a maximum nitrogen removal efficiency of 86.5%. Overall, this study implies that it is feasible to maintain granular sludge in a plug-flow PN/A reactor, and biofilm detachment significantly favors the granulation process.}, } @article {pmid34921854, year = {2022}, author = {di Biase, A and Flores-Orozco, D and Patidar, R and Kowalski, MS and Jabari, P and Kumar, A and Devlin, TR and Oleszkiewicz, JA}, title = {Performance and recovery of nitrifying biofilm after exposure to prolonged starvation.}, journal = {Chemosphere}, volume = {290}, number = {}, pages = {133323}, doi = {10.1016/j.chemosphere.2021.133323}, pmid = {34921854}, issn = {1879-1298}, mesh = {Ammonia ; *Biofilms ; *Bioreactors ; Nitrification ; Nitrites ; }, abstract = {Achieving consistent ammonia removal in post-lagoon processes faces two major challenges impacting nitrifiers due to the unique seasonal variation of lagoon-based systems: summer to winter temperature drop and summer to fall ammonia starvation period while lagoon is removing ammonia. The objective of this study was to follow microbial diversity and define conditions that could overcome these challenges in a post-lagoon moving bed biofilm reactor (MBBR) operated at an initial surface area loading rate (SALR) of 0.3 g-NH4-N m[-2]d[-1] from mesophilic (20 °C) to psychrophilic (4 °C). Initially the temperature was maintained at 20 °C and decreased to 10 °C until steady state was achieved. During starvation conditions (i.e., continuous, intermittent and no aeration without inflow; decanted media; and intermittent and continuous ammonia supplement) the temperature was decreased by 2 °C per week until 4 °C. The results indicated that operational procedures, such as intermittent ammonia supplement with SALR of 0.15 g-NH4-N m[-2]d[-1] could improve performance with 80% ammonia removal achieved immediately after starvation period. Intermittent ammonia supplement had produced the greatest biofilm preservation comparable to the initial load with the highest specific and surface area removal rates. In the recovery phase (initial load restoration) 10 days were required to reestablish performance above 95% ammonia removal. When temperature was decreased from mesophilic to psychrophilic, the microbial diversity was found higher when starving biofilm compared to the control operated at the initial load while it converged to a similar population over recovery. The main actors associated to nitrification enriched at psychrophilic conditions were Proteobacteria and Bacteriodotes at phyla level. Ammonia oxidation to nitrite was mainly driven by the order Burkholderiales and nitrite oxidation to nitrate by Pseudomonadales. This procedure should be considered in the implementation of full-scale post-lagoon MBBR technologies to ensure reliable, robust, and consistent performance despite the inherent seasonal variability of lagoon-based processes.}, } @article {pmid34920154, year = {2022}, author = {Domingues, PCA and Oliveira, VC and Bim, FL and Aires, CP and Santos, APD and Castro, DT and Silva-Lovato, CH and Andrade, D and Watanabe, E}, title = {Influence of glucose supplementation on biofilm formation of Candida albicans and Candida glabrata isolated from diabetic and non-diabetic individuals.}, journal = {Archives of oral biology}, volume = {134}, number = {}, pages = {105339}, doi = {10.1016/j.archoralbio.2021.105339}, pmid = {34920154}, issn = {1879-1506}, mesh = {Antifungal Agents ; Biofilms ; *Candida albicans ; Candida glabrata ; *Diabetes Mellitus ; Dietary Supplements ; Glucose ; Humans ; }, abstract = {OBJECTIVE: This study evaluated the effect of different glucose concentration on biofilm formation of Candida albicans and Candida glabrata strains isolated from diabetic and non-diabetic individuals.

METHODS: The study was divided into two stages: (I) selection and identification of 48 C. albicans and C. glabrata strains by polymerase chain reaction followed by restriction fragment length polymorphism analysis (PCR/RFLP); (II) evaluation of biofilm formation by means of viability rates (colony-forming units), biofilm dry matter (mg) and biofilm-covered areas (μm[2]). Statistical comparisons were performed through nonparametric analysis of longitudinal data in factorial experiments with pairwise comparisons using Friedman Conover's test (α = 0.05).

RESULTS: All the Candida spp. had their identifications confirmed by PCR/RFLP. C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed higher viability rates than strains from non-diabetic individuals. No difference was observed on viability of C. glabrata biofilm. Regarding biofilm dry matter, C. albicans biofilm of strains from diabetic individuals cultivated in different glucose concentration showed lower amount in weight than strains from non-diabetic individuals. In C. glabrata strains, this result was only observed in biofilms cultivated with no glucose supplementation. With regard to biofilm-covered areas, only glucose supplementation and non-diabetic condition showed a positive effect on C. albicans biofilm development, and no condition affected C. glabrata biofilm formation.

CONCLUSION: The strain type (C. albicans and C. glabrata) isolated from diabetic and non-diabetic individuals influenced on biofilm formation, but glucose supplementation did not.}, } @article {pmid34919191, year = {2021}, author = {Chen, Y and Cui, G and Cui, Y and Chen, D and Lin, H}, title = {Small molecule targeting amyloid fibrils inhibits Streptococcus mutans biofilm formation.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {171}, pmid = {34919191}, issn = {2191-0855}, support = {No. 81970928//National Natural Science Foundation of China/ ; }, abstract = {Amyloid fibrils are important scaffold in bacterial biofilms. Streptococcus mutans is an established cariogenic bacteria dwelling within biofilms, and C123 segment of P1 protein is known to form amyloid fibrils in S. mutans biofilms, among which C3 segment could serve as a promising anti-amyloid target due to its critical role in C123-P1 interactions. Recently, small molecules have been found to successfully inhibit biofilms by targeting amyloid fibrils. Thus, our study aimed to screen small molecules targeting C3 segment with the capacity to influence amyloid fibrils and S. mutans biofilms. In silico screening was utilized to discover promising small molecules, which were evaluated for their effects on bacterial cells and amyloid fibrils. We selected 99 small molecules and enrolled 55 small molecules named D1-D55 for crystal violet staining. Notably, D25 selectively inhibit S. mutans biofilms but had no significant influence on biofilms formed by Streptococcus gordonii and Streptococcus sanguinis, and D25 showed no bactericidal effects and low cytotoxicity. In addition, amyloid fibrils in free-floating bacteria, biofilms and purified C123 were quantified with ThT assays, and the differences were not statistically significant in the presence or absence of D25. Morphological changes of amyloid fibrils were visualized with TEM images, where amorphous aggregates were obvious coupled with long and atypical amyloid fibrils. Moreover, amyloid-related genes were upregulated in response to D25. In conclusion, D25 is a promising antimicrobial agent with the capacity to influence amyloid fibrils and inhibit S. mutans biofilms.}, } @article {pmid34917520, year = {2021}, author = {Oliveira, F and Rohde, H and Vilanova, M and Cerca, N}, title = {Fighting Staphylococcus epidermidis Biofilm-Associated Infections: Can Iron Be the Key to Success?.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {798563}, pmid = {34917520}, issn = {2235-2988}, mesh = {Biofilms ; Genes, Bacterial ; Humans ; Iron ; *Staphylococcal Infections ; *Staphylococcus epidermidis/genetics ; }, abstract = {Staphylococcus epidermidis is one of the most important commensal microorganisms of human skin and mucosae. However, this bacterial species is also the cause of severe infections in immunocompromised patients, specially associated with the utilization of indwelling medical devices, that often serve as a scaffold for biofilm formation. S. epidermidis strains are often multidrug resistant and its association with biofilm formation makes these infections hard to treat. Their remarkable ability to form biofilms is widely regarded as its major pathogenic determinant. Although a significant amount of knowledge on its biofilm formation mechanisms has been achieved, we still do not understand how the species survives when exposed to the host harsh environment during invasion. A previous RNA-seq study highlighted that iron-metabolism associated genes were the most up-regulated bacterial genes upon contact with human blood, which suggested that iron acquisition plays an important role in S. epidermidis biofilm development and escape from the host innate immune system. In this perspective article, we review the available literature on the role of iron metabolism on S. epidermidis pathogenesis and propose that exploiting its dependence on iron could be pursued as a viable therapeutic alternative.}, } @article {pmid34917252, year = {2021}, author = {Shchelik, IS and Gademann, K}, title = {Thiol- and Disulfide-Containing Vancomycin Derivatives Against Bacterial Resistance and Biofilm Formation.}, journal = {ACS medicinal chemistry letters}, volume = {12}, number = {12}, pages = {1898-1904}, pmid = {34917252}, issn = {1948-5875}, abstract = {Antibiotic-resistant and biofilm-associated infections constitute a rapidly growing issue. Use of the last-resort antibiotic vancomycin is under threat due to the increasing appearance of vancomycin-resistant bacteria as well as the formation of biofilms. Herein, we report a series of novel vancomycin derivatives carrying thiol- and disulfide-containing moieties. The new compounds exhibited enhanced antibacterial activity against a broad range of bacterial strains, including vancomycin-resistant microbes and Gram-negative bacteria. Moreover, all obtained derivatives demonstrated improved antibiofilm formation activity against VanB-resistant Enterococcus compared to vancomycin. This work establishes a promising strategy for combating drug-resistant bacterial infections or disrupting biofilm formation and advances the knowledge on the structural optimization of antibiotics with sulfur-containing modifications.}, } @article {pmid34917062, year = {2021}, author = {Hong, W and Nyaruaba, R and Li, X and Liu, H and Yang, H and Wei, H}, title = {In-situ and Real-Time Monitoring of the Interaction Between Lysins and Staphylococcus aureus Biofilm by Surface Plasmon Resonance.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {783472}, pmid = {34917062}, issn = {1664-302X}, abstract = {Staphylococcus aureus can produce a multilayered biofilm embedded in extracellular polymeric matrix. This biofilm is difficult to remove, insensitive to antibiotics, easy to develop drug-resistant strains and causes enormous problems to environments and health. Phage lysin which commonly consists of a catalytic domain (CD) and a cell-wall binding domain (CBD) is a powerful weapon against bacterial biofilm. However, the real-time interaction between lysin and S. aureus biofilm is still not fully understood. In this study, we monitored the interactions of three lysins (ClyF, ClyC, PlySs2) against culture-on-chip S. aureus biofilm, in real-time, based on surface plasmon resonance (SPR). A typical SPR response curve showed that the lysins bound to the biofilm rapidly and the biofilm destruction started at a longer time. By using 1:1 binding model analysis, affinity constants (K D) for ClyF, ClyC, and PlySs2 were found to be 3.18 ± 0.127 μM, 1.12 ± 0.026 μM, and 15.5 ± 0.514 μM, respectively. The fact that ClyF and PlySs2 shared the same CBD but showed different affinity to S. aureus biofilm suggested that, not only CBD, but also CD affects the binding activity of the entire lysin. The SPR platform can be applied to improve our understanding on the complex interactions between lysins and bacterial biofilm including association (adsorption) and disassociation (destruction).}, } @article {pmid34916809, year = {2021}, author = {Zeng, K and Zhang, JM and Li, XB and Peng, SX and Zhang, SC and Xie, WX and Xi, CF and Cao, CJ}, title = {Analysis of Bacterial Biofilm Formation in Patients with Malignancy Undergoing Double J Stent Indwelling and Its Influencing Factors.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {5209-5217}, pmid = {34916809}, issn = {1178-6973}, abstract = {OBJECTIVE: To analyze the bacterial biofilm (BF) formation in patients with malignancy undergoing double J stent indwelling and its influencing factors.

METHODS: A total of 167 patients with malignant tumors who received double J stent indwelling in the hospital from January 2018 to January 2021 were included in the study. The urine and double J stent samples were collected for bacterial identification and observed for BF formation on the surface of the urinary catheter under a scanning electron microscope (SEM). Univariate and multivariate logistic regression analyses were used to analyze the influencing factors of BF.

RESULTS: The BF formation rate was 34.73% (58/167). The BF formation rate of positive specimens cultured in urine and double J stent was significantly higher than that of negative ones (P<0.05). Staphylococcus was the main BF bacteria in double J stent and urine culture specimens, followed by Enterococcus, Pseudomonas, Enterobacter, and Acinetobacter. Compared with the non-BF group, the number of viable bacteria in the double J stent and urine and the catheterization time in the BF group rose markedly (P<0.05). Advanced age, chemotherapy, anemia, indwelling time ≥90d, and urinary tract infection were risk factors for BF formation in patients with malignancy undergoing double J stent indwelling (P<0.05).

CONCLUSION: There is a high rate of BF formation in patients with malignancy undergoing double J stent indwelling, with Staphylococcus as the dominant species. Treatment requires enhanced urinary catheter management and nutritional status to inhibit BF formation and lower the rate of urinary catheter-related infections.}, } @article {pmid34916515, year = {2021}, author = {McCall, AD and Pathirana, RU and Prabhakar, A and Cullen, PJ and Edgerton, M}, title = {Author Correction: Candida albicans biofilm development is governed by cooperative attachment and adhesion maintenance proteins.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {91}, pmid = {34916515}, issn = {2055-5008}, } @article {pmid34915291, year = {2022}, author = {Wang, Y and Lai, CY and Wu, M and Lu, X and Hu, S and Yuan, Z and Guo, J}, title = {Copper stimulation on methane-supported perchlorate reduction in a membrane biofilm reactor.}, journal = {Journal of hazardous materials}, volume = {425}, number = {}, pages = {127917}, doi = {10.1016/j.jhazmat.2021.127917}, pmid = {34915291}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors ; Copper ; *Methane ; Oxidation-Reduction ; Oxygenases ; *Perchlorates ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The present study demonstrated that the perchlorate reduction rate in a methane-based membrane biofilm reactor was significantly enhanced from 14.4 to 25.6 mg-Cl/L/d by increasing copper concentration in the feeding medium from 1 to 10 μM, indicating a stimulatory effect of copper on the methane-supported perchlorate reduction process. Batch tests further confirmed that the increased copper concentration enhanced both methane oxidation and perchlorate reduction rates, which was supported by an increasing trend of functional genes (pmoA for methanotrophs and pcrA for specific perchlorate reducers) abundances through quantitative polymerase chain reaction (qPCR). Both 16S rRNA gene sequencing and functional genes (pmoA and pcrA) sequencing jointly revealed that the biofilm supplied with a higher copper concentration exhibited a more diverse microbial community. The methane-supported perchlorate reduction was accomplished through a synergistic association of methanotrophs (Methylocystis, Methylomonas, and Methylocystaceae) and perchlorate reducers (Dechloromonas, Azospira, Magnetospirillum, and Denitratisoma). Acetate may function as the key syntrophic linkage between methanotrophs and perchlorate reducers. It was proposed that the increased copper concentration improved the activity of particulate methane monooxygenase (pMMO) for methane oxidation or promoted the biosynthesis of intracellular carbon storage compounds polyhydroxybutyrate (PHB) in methanotrophs for generating more acetate available for perchlorate reduction.}, } @article {pmid34914997, year = {2022}, author = {Stoffel, D and Rigo, E and Derlon, N and Staaks, C and Heijnen, M and Morgenroth, E and Jacquin, C}, title = {Low maintenance gravity-driven membrane filtration using hollow fibers: Effect of reducing space for biofilm growth and control strategies on permeate flux.}, journal = {The Science of the total environment}, volume = {811}, number = {}, pages = {152307}, doi = {10.1016/j.scitotenv.2021.152307}, pmid = {34914997}, issn = {1879-1026}, mesh = {Biofilms ; *Filtration ; Membranes, Artificial ; Renal Dialysis ; Ultrafiltration ; *Water Purification ; }, abstract = {The implementation of centralized drinking water treatment systems necessitates lower operational costs and improved biopolymer removal during ultrafiltration (UF), which can be afforded by gravity-driven membrane (GDM) filtration. However, prior to implementing GDM filtration in centralized systems, biofilm growth in compacted membrane configurations, such as inside-out hollow fiber (HF), and its impact on permeate flux need to be investigated. To this end, we operated modules with distinct limits on available space for biofilm growth: (1) outside-in 1.5 mm 7-capillary HF (non-limited), (2) inside-out 1.5 mm 7-capillary HF (limited), and (3) inside-out 0.9 mm 7-capillary HF (very limited). Here, we observed that the lower the space available for biofilm growth, the lower the permeate flux. To improve GDM performance with inside-out HF, we applied daily shear stress to the biofilm surface with forward flush (FF) or combined relaxation and forward flush (R+FF). We showed that applying shear stress to the biofilm surface was insufficient for controlling flux loss due to low available space for biofilm growth. At the experimental endpoint, we backwashed with a stepwise transmembrane pressure (TMP) increase or a single TMP on all inside-out HF modules, which removed the biofilm from its base. Afterwards, higher fluxes were yielded. We also showed that all modules exhibited a gradual increase in biopolymer removal followed by stabilization between 70 and 90%. Additionally, control of biofilm growth with surface shear stress did not affect biopolymer removal. In summary, the implementation of inside-out HF with GDM filtration is challenged by low available space for biofilm growth, but may be remedied with a regular backwash to remove biofilm from its base. We showed that a wider range of GDM applications are available; making GDM potentially compatible with implementation in centralized systems, if space limitation is taken into consideration for operation optimization.}, } @article {pmid34914360, year = {2022}, author = {Obuobi, S and Ngoc Phung, A and Julin, K and Johannessen, M and Škalko-Basnet, N}, title = {Biofilm Responsive Zwitterionic Antimicrobial Nanoparticles to Treat Cutaneous Infection.}, journal = {Biomacromolecules}, volume = {23}, number = {1}, pages = {303-315}, pmid = {34914360}, issn = {1526-4602}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Anti-Infective Agents ; Biofilms ; Microbial Sensitivity Tests ; *Nanoparticles/chemistry ; Staphylococcus aureus ; }, abstract = {To avert the poor bioavailability of antibiotics during S. aureus biofilm infections, a series of zwitterionic nanoparticles containing nucleic acid nanostructures were fabricated for the delivery of vancomycin. The nanoparticles were prepared with three main lipids: (i) neutral (soy phosphatidylcholine; P), (ii) positively charged ionizable (1,2-dioleyloxy-3-dimethylaminopropane; D), and (iii) anionic (1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1',2',3'-triazole) triethylene glycolmannose; M) or (cholesteryl hemisuccinate; C) lipids. The ratio of the anionic lipid was tuned between 0 and 10 mol %, and its impact on surface charge, size, stability, toxicity, and biofilm sensitivity was evaluated. Under biofilm mimicking conditions, the enzyme degradability (via dynamic light scattering (DLS)), antitoxin (via DLS and spectrophotometry), and antibiotic release profile was assessed. Additionally, biofilm penetration, prevention (in vitro), and eradication (ex vivo) of the vancomycin loaded formulation was investigated. Compared with the unmodified nanoparticles which exhibited the smallest size (188 nm), all three surface modified formulations showed significantly larger sizes (i.e., 222-277 nm). Under simulations of biofilm pH conditions, the mannose modified nanoparticle (PDM 90/5/5) displayed ideal charge reversal from a neutral (+1.69 ± 1.83 mV) to a cationic surface potential (+17.18 ± 2.16 mV) to improve bacteria binding and biofilm penetration. In the presence of relevant bacterial enzymes, the carrier rapidly released the DNA nanoparticles to function as an antitoxin against α-hemolysin. Controlled release of vancomycin prevented biofilm attachment and significantly reduced early stage biofilm formations within 24 h. Enhanced biocompatibility and significant ex vivo potency of the PDM 90/5/5 formulation was also observed. Taken together, these results emphasize the benefit of these nanocarriers as potential therapies against biofilm infections and fills the gap for multifunctional nanocarriers that prevent biofilm infections.}, } @article {pmid34913388, year = {2022}, author = {Oluyori, AP and Rode, HB}, title = {Mycobacterium tuberculosis biofilm inhibitors.}, journal = {Future medicinal chemistry}, volume = {14}, number = {4}, pages = {203-205}, doi = {10.4155/fmc-2021-0281}, pmid = {34913388}, issn = {1756-8927}, mesh = {Antitubercular Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Coordination Complexes/chemical synthesis/chemistry/pharmacology ; Gold/chemistry ; Microbial Sensitivity Tests ; Mycobacterium/drug effects ; Mycobacterium tuberculosis/*physiology ; }, } @article {pmid34910559, year = {2022}, author = {Goetz, C and Larouche, J and Velez Aristizabal, M and Niboucha, N and Jean, J}, title = {Efficacy of Organic Peroxyacids for Eliminating Biofilm Preformed by Microorganisms Isolated from Dairy Processing Plants.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {4}, pages = {e0188921}, pmid = {34910559}, issn = {1098-5336}, mesh = {Bacteria ; *Biofilms ; Dairying ; *Disinfectants/pharmacology ; Food-Processing Industry ; }, abstract = {The aim of this study was to evaluate the ability of microorganisms isolated from the dairy industry to form biofilms and to investigate the efficacy of organic peroxyacids (peracetic, perpropionic, and perlactic acids and BioDestroy) to eradicate those biofilms. Eighteen microorganisms were isolated from Quebec dairy processing plants that have issues associated with biofilm formation and were presumptively identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The single-species biofilm-producing ability of the isolates was then evaluated using 96-well microplates. Eight out of 18 of these isolates were identified as moderate or strong biofilm producers, and 10 out of 18 were negative or weak biofilm producers. The efficacy of the above-mentioned disinfectants was tested on the stronger biofilm-producing bacteria using the MBEC (minimum biofilm eradication concentration) assay. After 5 min, all disinfectants tested successfully eradicated both the single and mixed biofilms when applied following the recommended concentration. However, the efficacy of organic peroxyacids was significantly variable at lower concentrations. For example, 25 ppm of BioDestroy was sufficient to eradicate all the biofilms, except for Pseudomonas azotoformans PFl1A. Unfortunately, microscopic observations highlighted those dead cells were still attached to the surfaces. In conclusion, our results suggest that some microorganisms found in dairy plants can produce tenacious biofilms that are still susceptible to disinfectants, including organic peroxyacids. Further studies would be needed to confirm these observations using a dynamic method to mimic in vivo conditions. IMPORTANCE Biofilm-forming microorganisms are a major issue in the food industry, including the dairy industry, because of their negative impact on product quality. Biofilms are difficult to remove by clean-in-place (CIP) procedures commonly used in processing plants and may be less sensitive to sanitizers. Therefore, it is important to identify these microorganisms to develop biofilm control strategies. The results gathered in the present study could contribute to this aim, even though it was carried out using only static methods.}, } @article {pmid34908459, year = {2021}, author = {Archambault, L and Koshy-Chenthittayil, S and Thompson, A and Dongari-Bagtzoglou, A and Laubenbacher, R and Mendes, P}, title = {Understanding Lactobacillus paracasei and Streptococcus oralis Biofilm Interactions through Agent-Based Modeling.}, journal = {mSphere}, volume = {6}, number = {6}, pages = {e0087521}, pmid = {34908459}, issn = {2379-5042}, support = {R01 GM127909/GM/NIGMS NIH HHS/United States ; R01 DE013986/DE/NIDCR NIH HHS/United States ; R01 AI135128/AI/NIAID NIH HHS/United States ; U01 EB024501/EB/NIBIB NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Lacticaseibacillus paracasei/*growth & development ; Streptococcus oralis/*growth & development ; *Systems Analysis ; Virulence ; }, abstract = {As common commensals residing on mucosal tissues, Lactobacillus species are known to promote health, while some Streptococcus species act to enhance the pathogenicity of other organisms in those environments. In this study, we used a combination of in vitro imaging of live biofilms and computational modeling to explore biofilm interactions between Streptococcus oralis, an accessory pathogen in oral candidiasis, and Lactobacillus paracasei, an organism with known probiotic properties. A computational agent-based model was created where the two species interact only by competing for space, oxygen and glucose. Quantification of bacterial growth in live biofilms indicated that S. oralis biomass and cell numbers were much lower than predicted by the model. Two subsequent models were then created to examine more complex interactions between these species, one where L. paracasei secretes a surfactant, and another where L. paracasei secretes an inhibitor of S. oralis growth. We observed that the growth of S. oralis could be affected by both mechanisms. Further biofilm experiments support the hypothesis that L. paracasei may secrete an inhibitor of S. oralis growth, although they do not exclude that a surfactant could also be involved. This contribution shows how agent-based modeling and experiments can be used in synergy to address multiple species biofilm interactions, with important roles in mucosal health and disease. IMPORTANCE We previously discovered a role of the oral commensal Streptococcus oralis as an accessory pathogen. S. oralis increases the virulence of Candida albicans infections in murine oral candidiasis and epithelial cell models through mechanisms which promote the formation of tissue-damaging biofilms. Lactobacillus species have known inhibitory effects on biofilm formation of many microbes, including Streptococcus species. Agent-based modeling has great advantages as a means of exploring multifaceted relationships between organisms in complex environments such as biofilms. Here, we used an iterative collaborative process between experimentation and modeling to reveal aspects of the mostly unexplored relationship between S. oralis and L. paracasei in biofilm growth. The inhibitory nature of L. paracasei on S. oralis in biofilms may be exploited as a means of preventing or alleviating mucosal fungal infections.}, } @article {pmid34907763, year = {2020}, author = {Alves Coelho Trevisan, D and Aline Zanetti Campanerut-Sa, P and da Silva, AF and Farias Pereira Batista, A and Seixas, FAV and Peralta, RM and de Sa-Nakanishi, AB and de Abreu Filho, BA and Machinski Junior, M and Graton Mikcha, JM}, title = {Action of carvacrol in Salmonella Typhimurium biofilm: A proteomic study.}, journal = {Journal of applied biomedicine}, volume = {18}, number = {4}, pages = {106-114}, pmid = {34907763}, issn = {1214-0287}, mesh = {Biofilms ; Cymenes/pharmacology ; *Proteomics ; *Salmonella typhimurium/genetics ; }, abstract = {Carvacrol presents action in Salmonella Typhimurium biofilms, however the antibiofilm mechanism of this compound has not been fully established yet. In the present study, the aim was to evaluate protein profile changes in S. Typhimurium biofilm treated with carvacrol. Proteomic analysis of treated versus untreated biofilm showed several changes in proteins involved with S. Typhimurium biofilm and antioxidant activity. The proteins DsbA (thiol: disulfide interchange protein DsbA), LuxS (S-ribosylhomocysteine lyase), DksA (RNA polymerase binding transcription factor DksA), and SODs (superoxide dismutases) A, B and C had their synthesis decreased after treatment with carvacrol. These proteins play a key role in S. Typhimurium biofilm formation, demonstrating the dynamic antibiofilm action of carvacrol. The differentially expressed proteins identified provide possible action targets for future studies in order to gain more insight into the mechanism of action of carvacrol on S. Typhimurium biofilm.}, } @article {pmid34907618, year = {2021}, author = {Bhattacharyya, D and Banerjee, J and Habib, M and Thapa, G and Samanta, I and Nanda, PK and Dutt, T and Sarkar, K and Bandyopadhyay, S}, title = {Elucidating the resistance repertoire, biofilm production, and phylogenetic characteristics of multidrug-resistant Escherichia coli isolated from community ponds: A study from West Bengal, India.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {94}, number = {1}, pages = {e1678}, doi = {10.1002/wer.1678}, pmid = {34907618}, issn = {1554-7531}, support = {//CAAST-Advanced Centre for Livestock Health (ACLH)/ ; //ICAR-World Bank/ ; //National Agricultural Higher Education Project (NAHEP)/ ; }, abstract = {This study details about the phenotypic and molecular characteristics of multidrug-resistant (MDR) Escherichia coli in the fresh community pond water (n = 257) collected from three districts of West Bengal, India. In total, 57 isolates were MDR of which 38 emerged as extended spectrum and 7 as AmpC-type β-lactamase producers in phenotypic assay. Among β-lactamase genes, blaCTXM-1was predominant (87.71%) followed by blaAmpC (77.2%) and blaTEM-1 (22.8%). Six MDR strains carried metallo-β-lactamase (MBL, blaNDM-1) gene. Tissue culture plate assay confirmed strong biofilm (SP) production in four MDR and one non-MDR isolates. In PCR-based replicon typing (PBRT), multiple plasmids of diverse replicon types (Frep, FIB, I1, FIA, K/B, HI1, and Y) were identified. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR)-based phylogenetic analysis revealed a high degree of genetic divergence among the MDR isolates. Multiplex PCR-based phylogrouping categorized 11 isolates as virulent (B2/D/F), which carried blaCTXM-1 gene and three had blaNDM-1 gene. Relative transcriptional activity of AcrAB efflux pump was significantly elevated among the SP and MBL producers. The presence of MDR E. coli isolates, particularly those resistant to carbapenem, in pond water used for daily domestic and household work, is a cause of concern as these pathogens may sneak into human food chain causing life-threatening infections. PRACTITIONER POINTS: Multidrug-resistant biofilm producing E. coli isolated from community pond water. A few of them were carbapenem-resistant and belonged to virulent (B2/D) types. Expression of AcrAB efflux pumps was found significantly elevated among biofilm producers and carbapenem-resistant population.}, } @article {pmid34906789, year = {2022}, author = {Qi, M and Liu, Q and Liu, Y and Yan, H and Zhang, Y and Yuan, Y}, title = {Staphylococcus aureus biofilm inhibition by high voltage prick electrostatic field (HVPEF) and the mechanism investigation.}, journal = {International journal of food microbiology}, volume = {362}, number = {}, pages = {109499}, doi = {10.1016/j.ijfoodmicro.2021.109499}, pmid = {34906789}, issn = {1879-3460}, mesh = {*Bacterial Adhesion ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Staphylococcus aureus ; Static Electricity ; }, abstract = {The study was to investigate the inhibitory effect and mechanism of high voltage prick electrostatic field (HVPEF) on Staphylococcus aureus biofilms. Results showed that HVPEF effectively inactivated 24-h and 48-h established S. aureus biofilms, and the effect was verified on different food-contact materials. Confocal laser scanning microscopy and scanning electron microscopy analysis suggested that HVPEF disintegrated the established biofilms by killing the embedded bacteria, but it hardly reduced the bacteria adhesion. HVPEF also effectively inhibit the formation of S. aureus biofilms, the effects varied with electric voltage, treatment time and biofilm culture conditions. The direct effect of HVPEF on planktonic S. aureus was a possible mode of biofilm formation inhibition. HVPEF also suppressed biofilm formation by reducing the release of key compositions of extracellular polymeric substance, including extracellular DNA (eDNA), protein and polysaccharide intercellular adhesion (PIA), and regulating the expression of biofilm formation related genes (icaA, ebh, cidA, sarA, icaR and sigB). We propose HVPEF as a novel method to inhibit bacteria biofilm, based on the results, HVPEF has positive effects to prevent biofilm-associated contamination of S. aureus.}, } @article {pmid34906703, year = {2022}, author = {Ahmar Siddiqui, M and Kumar Biswal, B and Siriweera, B and Chen, G and Wu, D}, title = {Integrated self-forming dynamic membrane (SFDM) and membrane-aerated biofilm reactor (MABR) system enhanced single-stage autotrophic nitrogen removal.}, journal = {Bioresource technology}, volume = {345}, number = {}, pages = {126554}, doi = {10.1016/j.biortech.2021.126554}, pmid = {34906703}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; *Denitrification ; *Nitrogen ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid ; }, abstract = {The membrane aerated biofilm reactor (MABR) is a novel bioreactor technology, facilitating single-stage autotrophic nitrogen removal. Two laboratory-scale MABRs equipped with non-woven fabrics were operated simultaneously without and with a self-forming dynamic membrane (SFDM) filtration module. After 87 days of operation (system start-up), the reactor incorporated with SFDM filtration showed better performance in terms of total nitrogen removal (>80%) and effluent suspended solid (less than1 mg/L) than the MABR in the up flow anaerobic sludge blanket (UASB) configuration (i.e., without SFDM). The incorporation of SFDM has the ability to retain more slow growing biomass (anammox) inside the reactor. Microbial characterization by 16S rRNA-based amplicon sequencing shows that the abundance and composition of microbial communities in two MABR systems were different, i.e., the genusRhodanobacterwas abundant in UASB-MABR, while Calorithrixwas dominant in SFDM-MABR. PCA-based statistical analysis demonstrated a positive association between reactor performance, membrane characteristics and microbial communities.}, } @article {pmid34905101, year = {2021}, author = {Li, X and Sun, J and Zhang, M and Xue, X and Wu, Q and Yang, W and Yin, Z and Zhou, D and Lu, R and Zhang, Y}, title = {The Effect of Salinity on Biofilm Formation and c-di-GMP Production in Vibrio parahaemolyticus.}, journal = {Current microbiology}, volume = {79}, number = {1}, pages = {25}, pmid = {34905101}, issn = {1432-0991}, support = {82072239//national natural science foundation of china/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Cyclic GMP/analogs & derivatives ; Gene Expression Regulation, Bacterial ; Salinity ; *Vibrio parahaemolyticus/genetics/metabolism ; }, abstract = {Vibrio parahaemolyticus is a moderately halophilic, salt-requiring organism that exhibits optimal growth at approximately 3% salt. Thus, salinity stress is one of the most important stimuli during its lifecycle. The bacterium possesses a strong ability to form biofilms on surfaces, which are thought to be involved in protecting it from adverse environmental conditions. In the present study, salinity-dependent biofilm formation by V. parahaemolyticus was investigated by combining crystal violet staining, colony morphology, intracellular c-di-GMP quantification and quantitative PCR. The results showed that biofilm formation by V. parahaemolyticus was significantly enhanced in low salinity growth conditions and was affected by incubation time. In addition, low salinity reduced intracellular c-di-GMP degradation in V. parahaemolyticus. Transcription of genes encoding ScrABC and ScrG proteins, which are involved in intracellular c-di-GMP metabolism, was inhibited by low salinity growth conditions. Thus, reduced intracellular c-di-GMP degradation in V. parahaemolyticus in low salinity growth conditions may be mediated by repression of scrG and scrABC transcription. Taken together, these results demonstrated for the first time that salinity regulates biofilm formation and c-di-GMP production in V. parahaemolyticus.}, } @article {pmid34905099, year = {2021}, author = {Jha, S and Bhadani, NK and Kumar, A and Sengupta, TK}, title = {Glucose-Induced Biofilm Formation in Bacillus thuringiensis KPWP1 is Associated with Increased Cell Surface Hydrophobicity and Increased Production of Exopolymeric Substances.}, journal = {Current microbiology}, volume = {79}, number = {1}, pages = {24}, pmid = {34905099}, issn = {1432-0991}, mesh = {*Bacillus thuringiensis ; Biofilms ; Extracellular Polymeric Substance Matrix ; Glucose ; Hydrophobic and Hydrophilic Interactions ; }, abstract = {Bacillus thuringiensis is an agriculturally and medically important bacteria as it produces insecticidal Cry proteins and can form biofilm on different plant surfaces. Previous studies reported that the ubiquitous carbon source glucose could induce restricted motility and fractal pattern formation in the growing colonies of pH, salt and arsenate tolerant Bacillus thuringiensis KPWP1. As bacteria are evolved with the ability to exhibit multicellular behavior and biofilm formation under limiting conditions for survival, the present study was focused on exploring the effect of glucose in biofilm formation by Bacillus thuringiensis KPWP1. A significant rise in biofilm loads was observed with increased glucose concentrations in growth media. Compared to control, six times more biofilm load was marked in presence of 2% of glucose. Interestingly, it was observed that the effect was glucose specific and also not due to any change in the sugar-induced physicochemical property of the growth media as the addition of galactose or arabinose could not induce any significant increase in KPWP1 biofilm load. Scanning electron-, confocal laser scanning-microscopic studies and biochemical tests revealed that increased concentrations of glucose could induce increased production of exopolymeric substances, increased number of densely-packed micro-colonies in KPWP1 biofilm and increased hydrophobicity and adherence properties in KPWP1cells.}, } @article {pmid34905092, year = {2021}, author = {She, P and Li, S and Liu, Y and Xu, L and Zhou, L and Zeng, X and Li, Y and Liu, S and Li, Z and Hussain, Z and Wu, Y}, title = {Repurposing Sitafloxacin, Prulifloxacin, Tosufloxacin, and Sisomicin as Antimicrobials Against Biofilm and Persister Cells of Pseudomonas aeruginosa.}, journal = {Current microbiology}, volume = {79}, number = {1}, pages = {12}, pmid = {34905092}, issn = {1432-0991}, support = {82072350//national natural science foundation of china/ ; 2019JJ80029//natural science foundation of hunan province/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Dioxolanes ; Drug Repositioning ; Fluoroquinolones/pharmacology ; Microbial Sensitivity Tests ; Naphthyridines ; Piperazines ; *Pseudomonas aeruginosa ; Sisomicin ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous bacterium found in hospitals and the surrounding environment. The ability of P. aeruginosa to form biofilms confers high-level resistance to antibiotics, and the persister cells formed in the presence of high antibacterial drug concentrations make P. aeruginosa-related infections more refractory. Further, there rarely is an effective antimicrobial alternative when biofilm- and persister cell-targeting treatment fails. Using a high-throughput screening assay, we previously identified fluoroquinolones sitafloxacin, prulifloxacin, and tosufloxacin as well as aminoglycoside sisomicin among FDA-approved drugs with significant bactericidal activity against P. aeruginosa. In addition, in our current study, these antibiotics exhibited an effective time- and dose-dependent eradication effects against the preformed biofilms of P. aeruginosa at the concentrations of 2-4 μM. These agents also exhibited bactericidal efficacy against CCCP-induced P. aeruginosa persister cells with the viable cell count decreased from 9.14 log10 CFU/mL to 6.15 (sitafloxacin), 7.59 (prulifloxacin), 4.27 (tosufloxacin), and 6.17 (sisomicin) log10 CFU/mL, respectively, following 4 h of treatment. Furthermore, sisomicin was also effective against conventional antibiotics induced persister cells in a time-dependent manner within 24 h. In addition, we confirmed the in vivo anti-biofilm efficacy of the identified antibiotics in a subcutaneous implantation biofilm-related infection model. Tosufloxacin exhibited the greatest in vivo bactericidal activity against P. aeruginosa biofilms with a reduction of 4.54 ΔLog10 CFU/mL compared to the vehicle group, followed by prulifloxacin, sitafloxacin, and sisomicin. Taken together, our results indicate that sitafloxacin, prulifloxacin, tosufloxacin, and sisomicin have great potential as alternatives for the treatment of refractory infections caused by P. aeruginosa biofilms and persister cells.}, } @article {pmid34904540, year = {2022}, author = {Qasemi, A and Rahimi, F and Katouli, M}, title = {Clonal groups of extended-spectrum β-lactamase and biofilm producing uropathogenic Escherichia coli in Iran.}, journal = {Pathogens and global health}, volume = {116}, number = {8}, pages = {485-497}, pmid = {34904540}, issn = {2047-7732}, mesh = {Humans ; Anti-Bacterial Agents/pharmacology/therapeutic use ; beta-Lactamases/genetics ; Biofilms ; *Escherichia coli Infections/epidemiology/microbiology ; Iran/epidemiology ; Microbial Sensitivity Tests ; *Urinary Tract Infections/epidemiology ; *Uropathogenic Escherichia coli/genetics ; }, abstract = {Pathogenicity of a bacterium is affected by the social characteristics of the population and environmental factors. The ability of biofilm formation among β-lactamase-producing uropathogenic Escherichia coli (UPEC) could facilitate the exchange of antibiotic-resistance genes, which resulted in widespread dissemination of antibacterial drug resistance. We investigated the prevalence of biofilm and β-lactamase producing UPECs among patients with urinary tract infection (UTI) in two cities with different demographics and climates in Iran. A total of 265 E. coli was isolated from patients with UTIs from two referral hospitals (n = 191) and two outpatient clinics (n = 74) in Isfahan and Zahedan, Iran. Production of curli and cellulose, and, biofilm formation was investigated using Congo red agar and microtiter plate methods, respectively. Biofilm producing (BFP) isolates (n = 107) were further characterized using rep-PCR, antimicrobial susceptibility testing and extended-spectrum β-lactamase (ESBL)/AmpC phenotypic production. Isolates were also screened for the presence of carbapenemase, ESBL and AmpC genes using multiplex PCR. High diversity was found among BFP strains in both cities, with 58% strains producing ESBL and 21% producing AmpC. ESBL (98%), AmpC (50%) and carbapenemase genes (40%) were identified in BFP strains with ESBL-positive phenotype, respectively. The prevalence of BFP strains, antibiotic resistance and β-lactamase genes in Zahedan, a low socioeconomic city with a warm climate, was significantly higher than that of Isfahan. High prevalence of biofilm and β-lactamase producing UPEC strains among strains from Zahedan suggests that socioeconomic status and environmental factors might have a role in pathogenicity of the strains.}, } @article {pmid34903146, year = {2021}, author = {Arenas, J and Szabo, Z and van der Wal, J and Maas, C and Riaz, T and Tønjum, T and Tommassen, J}, title = {Serum proteases prevent bacterial biofilm formation: role of kallikrein and plasmin.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {2902-2917}, pmid = {34903146}, issn = {2150-5608}, mesh = {Adhesins, Bacterial/genetics ; Biofilms ; *Fibrinolysin/metabolism ; Kallikreins/metabolism ; *Neisseria meningitidis/genetics ; }, abstract = {Biofilm formation is a general strategy for bacterial pathogens to withstand host defense mechanisms. In this study, we found that serum proteases inhibit biofilm formation by Neisseria meningitidis, Neisseria gonorrhoeae, Haemophilus influenzae, and Bordetella pertussis. Confocal laser-scanning microscopy analysis revealed that these proteins reduce the biomass and alter the architecture of meningococcal biofilms. To understand the underlying mechanism, the serum was fractionated through size-exclusion chromatography and anion-exchange chromatography, and the composition of the fractions that retained anti-biofilm activity against N. meningitidis was analyzed by intensity-based absolute quantification mass spectrometry. Among the identified serum proteins, plasma kallikrein (PKLK), FXIIa, and plasmin were found to cleave neisserial heparin-binding antigen and the α-peptide of IgA protease on the meningococcal cell surface, resulting in the release of positively charged polypeptides implicated in biofilm formation by binding extracellular DNA. Further experiments also revealed that plasmin and PKLK inhibited biofilm formation of B. pertussis by cleaving filamentous hemagglutinin. We conclude that the proteolytic activity of serum proteases toward bacterial adhesins involved in biofilm formation could constitute a defense mechanism for the clearance of pathogens.}, } @article {pmid34902482, year = {2022}, author = {Yang, S and Huang, Q and Feng, Y and Ren, X and Wang, J and Yu, Y}, title = {The anode is more beneficial to the advanced treatment of wastewater containing antibiotics by three-dimensional electro-biofilm reactor: Degradation, mechanism and optimization.}, journal = {Bioresource technology}, volume = {345}, number = {}, pages = {126473}, doi = {10.1016/j.biortech.2021.126473}, pmid = {34902482}, issn = {1873-2976}, mesh = {Anti-Bacterial Agents ; Biofilms ; Bioreactors ; Electrodes ; Waste Disposal, Fluid ; *Wastewater ; *Water Purification ; }, abstract = {The three-dimensional electrode biological aerated filter (3DE-BAF) has the potential to overcome inherent limitations of conventional electrochemical and biofilm methods. Electrochemical means could enhance the performance and sustainability of biofilm technologies and stimulate the spread of new applications in (waste) water treatment. This paper describes the construction and performance of 3DE-BAF in the treatment of simulated wastewater represented by tetracycline (TC). This is followed by a discussion of electrode performance, the electron transport mechanism and the electrode's effect on the biological community of 3D-EBAF. Given the gap between experimental studies and practical applications, the enlarged anode 3DE-BAF named 3DEAE-BAF reactor was applied with good results to duck farm wastewater. This study could provide guidance as to developing new methods to construct a highly stable 3DE-BAF. The paper concludes that improved 3DE-BAF technology is promising for advanced treatment of livestock wastewater containing antibiotics.}, } @article {pmid34902408, year = {2022}, author = {Djaoudi, K and Onrubia, JAT and Boukra, A and Guesnay, L and Portas, A and Barry-Martinet, R and Angeletti, B and Mounier, S and Lenoble, V and Briand, JF}, title = {Seawater copper content controls biofilm bioaccumulation and microbial community on microplastics.}, journal = {The Science of the total environment}, volume = {814}, number = {}, pages = {152278}, doi = {10.1016/j.scitotenv.2021.152278}, pmid = {34902408}, issn = {1879-1026}, mesh = {Bioaccumulation ; Biofilms ; Copper/toxicity ; *Microbiota ; Microplastics ; Plastics ; Seawater ; *Water Pollutants, Chemical/analysis ; }, abstract = {The adsorption of trace metals on microplastics (MPs) is affected by the presence of surficial biofilms but their interactions are poorly understood. Here, we present the influence of Cu levels in real seawater (Toulon Bay, NW Mediterranean Sea) on microbial communities and Cu content of the resulting biofilms grown during incubation experiments on high density polyethylene. Two sets of incubation experiments were run with seawater supplied with MPs, sampled in two sites with contrasting Cu levels: Pt12 (most contaminated site) and Pt41P (less contaminated site). For each incubation experiment, 5 treatments were considered differing in Cu concentrations, ranging between 30 and 400 nM and between 6 and 60 nM, for Pt12 and Pt41p, respectively. A control experiment (filtered at 0.2 μm) was run in parallel for each incubation experiment. We observed that, at the time scale of the incubation period, both prokaryotic and eukaryotic richness and diversity were higher in the biofilms formed from the most contaminated site. In addition, we showed that Cu levels are shaping biofilm communities, evidencing co-occurrence patterns between prokaryotes and eukaryotes with diatoms playing a central role. These differences in biofilm formation were reflected in the amount of bioaccumulated Cu per dry weight of MPs, exhibiting higher values in the most contaminated site. Within this site, the increase of Cu seawater content enhanced its bioaccumulation onto MPs until reaching saturation. This study strongly suggests a striking link between seawater copper content, biofilm community shaping and the resulting Cu bioaccumulation onto MPs.}, } @article {pmid34900167, year = {2021}, author = {Goodarzi, F and Hallajzadeh, M and Sholeh, M and Talebi, M and Mahabadi, VP and Amirmozafari, N}, title = {Biological characteristics and anti-biofilm activity of a lytic phage against vancomycin-resistant Enterococcus faecium.}, journal = {Iranian journal of microbiology}, volume = {13}, number = {5}, pages = {691-702}, pmid = {34900167}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: An important leading cause of the emergence of vancomycin-resistant enterococci, especially Enterococcus faecium, is the inefficiency of antibiotics in the elimination of drug-resistant pathogens. Consequently, the need for alternative treatments is more necessary than ever.

MATERIALS AND METHODS: A highly effective bacteriophage against vancomycin-resistant E. faecium called vB-EfmS-S2 was isolated from hospital sewage. The biological properties of phage S2 and its effect on biofilm structures were determined.

RESULTS: Phage S2 was specifically capable of lysing a wide range of clinical E. faecium isolates. According to Electron microscopy observations, the phage S2 belonged to the Siphoviridea family. Suitable pH spectra for phage survival was 5-11, at which the phage showed 100% activity. The optimal temperature for phage growth was 30-45°C, with the highest growth at 37°C. Based on one-step growth curve results, the latent period of phage S2 was 14 min with a burst size of 200 PFU/ml. The phage S2 was also able to tolerate bile at concentrations of 1 and 2% and required Mg2+ for an effective infection cycle. Biofilms were significantly inhibited and disrupted in the presence of the phage.

CONCLUSION: According to the results, phage S2 could potentially be an alternative for the elimination and control of vancomycin-resistant E. faecium biofilm.}, } @article {pmid34898472, year = {2021}, author = {Suneel Kumar, A and Smiline Girija, AS and Naga Srilatha, B}, title = {Characterization of biofilm producing methicillin resistant coagulase negative Staphylococci from India.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {}, number = {}, pages = {}, doi = {10.1556/030.2021.01538}, pmid = {34898472}, issn = {1588-2640}, abstract = {Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) cause infectious diseases due to their potential to form biofilm and further colonization in hospital materials. This study evaluated the antibiotic susceptible phenotypes, biofilm-producing ability, and biofilm-associated genes (mecA, icaAD, bap, cna, and fnbA). Biofilm formation was detected through Congo red agar (CRA) method and MTP method. The presence of biofilm and associated genes in MR-CoNS were detected by PCR. A total of 310 (55.95%) isolates produced the biofilm. Among these isolates, Staphylococcus haemolyticus (34.83%), Staphylococcus epidermis (31.93%), Staphylococcus capitis (16.77%), Staphylococcus cohnii (10.96%), and Staphylococcus hominis (5.48%) were identified. The antimicrobial susceptibility pattern of CoNS isolates indicated resistance to cefoxitin (100%), erythromycin (94.8%), ciprofloxacin (66.7%), sulfamethoxazole/trimethoprim (66.7%), gentamicin (66.12%), and clindamycin (62.9%). Resistance rate to mupirocin was 48.5% in S. epidermidis and 38.9% in S. haemolyticus isolates. All isolates were sensitive to vancomycin and linezolid. The prevalence rates of icaAD, bap, fnbA, and cna were 18.06%, 12.5%, 47.4%, and 27.4%, respectively. icaAD and bap genes were detected in 18.06% and 12.5% of MR-CoNS isolates. fnbA and cna genes were detected in 47.41% and 27.41% of MRCoNS isolates. icaAD positive strains exhibited a significant increase in the biofilm formation compared with those that lacked icaAD (0.86 (0.42, 1.39) versus 0.36 (0.14, 0.75), respectively; P < 0.001). In conclusion, the majority of MR-CoNS isolates were biofilm producers, and S. capitis, which possessed icaAD genes, ranked as the great biofilm producer than other Staphylococcus. The study's findings are important to form a strategy to control biofilm formation as an alternative strategy to counter the spread of MR-CoNS in healthcare settings.}, } @article {pmid34897974, year = {2022}, author = {Ichioka, Y and Derks, J and Dahlén, G and Berglundh, T and Larsson, L}, title = {Mechanical removal of biofilm on titanium discs: An in vitro study.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {110}, number = {5}, pages = {1044-1055}, doi = {10.1002/jbm.b.34978}, pmid = {34897974}, issn = {1552-4981}, mesh = {Bacteria ; Biofilms ; *Dental Implants ; Microscopy, Electron, Scanning ; Osteoblasts ; Surface Properties ; *Titanium/pharmacology ; }, abstract = {The objective of this in vitro study was to evaluate surface cleanness and cytocompatibility following mechanical instrumentation of biofilm-contaminated titanium surfaces. Titanium discs (non-modified [Ti(s)] and shot-blasted surfaces [Ti(r)]) contaminated with Streptococcus gordonii were instrumented using four different techniques: (i) gauze soaked in saline (GS), (ii) ultra-sonic device (US), (iii) rotating nickel-titanium brush (TiB), or (iv) air-polishing device (AP). Non-contaminated, untreated titanium disks were used as controls (C). Residual deposits and cytocompatibility for osteoblast-like cells were evaluated using scanning electron microscopy, immunofluorescence, and reverse transcriptase polymerase chain reaction. While the number of residual bacteria on Ti(s) discs was close to 0 in all treatment groups, significantly higher mean numbers of residual bacteria were observed on Ti(r) discs for GS (152.7 ± 75.7) and TiB (33.5 ± 22.2) than for US (0) and AP (0). Instrumentation with US resulted in deposition of foreign material (mean area% of foreign material: 3.0 ± 3.6% and 10.8 ± 9.6% for Ti(s) and Ti(r) discs, respectively). AP was the most effective decontamination procedure in reducing bacteria without depositing residual foreign material on Ti(r) discs. TiB and AP were superior methods in restoring cytocompatibility, although no method of mechanical decontamination resulted in pristine levels of cytocompatibility.}, } @article {pmid34896965, year = {2022}, author = {Araújo, PM and Batista, E and Fernandes, MH and Fernandes, MJ and Gama, LT and Fraqueza, MJ}, title = {Assessment of biofilm formation by Campylobacter spp. isolates mimicking poultry slaughterhouse conditions.}, journal = {Poultry science}, volume = {101}, number = {2}, pages = {101586}, pmid = {34896965}, issn = {1525-3171}, mesh = {Abattoirs ; Animals ; Biofilms ; *Campylobacter/genetics ; *Campylobacter Infections/veterinary ; *Campylobacter jejuni ; Chickens ; Poultry ; }, abstract = {This research aimed to assess the biofilm formation ability of Campylobacter strains under temperature and oxygen stress conditions, similar to those found in the industrial environment, to explain the persistence of this pathogen on the poultry slaughter line. A collection of C. jejuni and C. coli isolates (n = 143) obtained from poultry samples (cecal content and neck skin), collected at slaughterhouse level, from diverse flocks, on different working days, was genotyped by flaA-restriction fragment length polymorphism (RFLP) typing method. A clustering analysis resulted in the assignment of 10 main clusters, from which 15 strains with different flaA-RFLP genotypes were selected for the assessment of biofilm formation ability and antimicrobial susceptibility. Biofilm assays, performed by crystal violet staining method, were conducted with the goal of mimicking some conditions present at the slaughterhouse environment, based on temperature, atmosphere, and contamination levels. Results indicated that many C. jejuni strains with similar flaA-RFLP profiles were present at the slaughterhouse on different processing days. All the strains tested (n = 15) were multidrug-resistant except for one. Biofilm formation ability was strain-dependent, and it appeared to have been affected by inoculum concentration, temperature, and tolerance to oxygen levels. At 10°C, adherence levels were significantly lower than at 42°C. Under microaerobic and aerobic atmospheres, at 42°C, 3 strains (C. jejuni 46E, C. jejuni 61C, and C. coli 65B) stood out, exhibiting significant levels of biofilm formation. C. jejuni strains 46E and 61C were inserted in clusters with evidence of persistence at the slaughterhouse for a long period of time. This study demonstrated that Campylobacter strains from broilers are capable of forming biofilms under conditions resembling the slaughterhouse environment. These results should be seen as a cue to improve the programs of hygiene implemented, particularly in those zones that can promote biofilm formation.}, } @article {pmid34896547, year = {2022}, author = {Puah, SM and Fong, SP and Kee, BP and Puthucheary, SD and Chua, KH}, title = {Molecular identification and biofilm-forming ability of Elizabethkingia species.}, journal = {Microbial pathogenesis}, volume = {162}, number = {}, pages = {105345}, doi = {10.1016/j.micpath.2021.105345}, pmid = {34896547}, issn = {1096-1208}, mesh = {Biofilms ; *Flavobacteriaceae/genetics ; *Flavobacteriaceae Infections ; Humans ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {Recently, Elizabethkingia species have gained attention as a cause of life-threatening infections. The identification via phenotypic methods of three important species- Elizabethkingia meningoseptica, E. anophelis and E. miricola is difficult. Our objectives were to re-assess 30 archived Flavobacterium meningosepticum isolates using 16S rRNA gene sequencing, ERIC-PCR, and biofilm formation assay. Twenty-four isolates were re-identified as E. anophelis and 6 as E. miricola. All of them had the ability to form biofilm as shown in microtiter plate assay based on crystal violet staining. Overall, E. anophelis had a higher specific biofilm formation index compared to E. miricola. A total of 42% (10 out of 24) of E. anophelis were classified as strong, 29% (7 out of 24) as moderate and 29% (7 out of 24) as weak biofilm producers. E. miricola, 17% (1 out of 6) isolates were strong biofilm producers, 50% (3 out of 6) moderate and 33% (2 out of 6) were weak producers. E. anophelis from tracheal secretions were significantly associated with (p = 0.0361) strong biofilm formation. In summary, this study showed that the isolates originally identified as F. meningosepticum were re-classified using the 16S rRNA gene as one of two Elizabethkingia species. The ability of E. anophelis to form strong biofilm in endotracheal tubes indicates their probable role in the pathogenesis of Elizabethkingia infections.}, } @article {pmid34896486, year = {2022}, author = {Zhang, H and Zhang, SS and Zhu, L and Li, YP and Chen, L}, title = {Phosphorus recovery in the alternating aerobic/anaerobic biofilm system: Performance and mechanism.}, journal = {The Science of the total environment}, volume = {810}, number = {}, pages = {152297}, doi = {10.1016/j.scitotenv.2021.152297}, pmid = {34896486}, issn = {1879-1026}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; *Phosphorus ; Polyphosphates ; Sewage ; }, abstract = {To balance the high phosphorus concentration in recirculated solution and the stability of biofilm system, this study explored the performance and mechanism of phosphorus uptake/release for recovering phosphorus from sewage when the phosphorus content in biofilm (Pbiofilm) changed. The results showed that the maximum phosphorus concentration in the concentrated solution reached 171.2 ± 2.5 mg·L[-1] in harvest 1st-5th stages. Polyphosphate accumulating organisms (PAOs) performed a metabolic shift from glycogen accumulation metabolism (GAM) to polyphosphate accumulation metabolism (PAM) when Pbiofilm increased at each phosphorus enrichment stage, and more phosphorus was absorbed/released by PAOs. Nevertheless, the release of poly-phosphate from PAOs was inhibited after phosphorus concentration stabilized, and PAOs were unable to absorb phosphorus from wastewater as it reached the phosphorus saturation stage. To maintain the stability of the system, phosphorus had to be harvested so that the saturated phosphorus in PAOs was easily released in a new recirculated solution, resulting in adequate storage space for PAOs to absorb phosphorus. Meanwhile, the [31]P NMR analysis demonstrated that phosphorus was stored in EPS and cell of PAOs, whereas EPS played a significant role than cell at the anaerobic phase. Particularly, ortho-phosphate was the major component of phosphorus release by EPS and poly-phosphate was the major part of phosphorus release by cell. Furthermore, the change of Pbiofilm had no impact on biofilm characteristics and microbial communities, whereas some PAOs would be enriched, and others that were not suitable for this process would be inhibited with repeated cycles of alternating aerobic/anaerobic operation.}, } @article {pmid34896477, year = {2022}, author = {Moreira, TA and Antolínez, IV and Valença, WO and Roy, S and Ramirez, I and Barbosa, LCA and Ren, D}, title = {Cadiolide analogues and their precursors as new inhibitors of bacterial quorum sensing and biofilm formation.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {57}, number = {}, pages = {128498}, doi = {10.1016/j.bmcl.2021.128498}, pmid = {34896477}, issn = {1464-3405}, mesh = {4-Butyrolactone/chemical synthesis/*pharmacology ; Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects/physiology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/physiology ; Quorum Sensing/*drug effects ; Stereoisomerism ; }, abstract = {Bacterial quorum sensing (QS) and biofilm formation are promising targets for developing new therapies to treat chronic infections. Herein, we report the stereoselective synthesis of 18 new analogs of natural cadiolides. Among the new compounds, substances 8b, 8f, 8i, 9a, 9b and 9e completely inhibited the biofilm formation of Escherichia coli RP347 in vitro. In addition, compound 8b interfered acyl-homoserine lactone (AHL) mediated QS, while 9e interrupted the QS via autoinducer-2 (AI-2). Biological assays also revealed that synthetic intermediates alkynones are potent inhibitors of AI-2 and AHL-mediated QS. These results indicate that cadiolides and alkynones are good candidates for further structural modification for a new generation of more potent antimicrobial agents.}, } @article {pmid34894599, year = {2022}, author = {Costa, NL and Olorounto, G and Lebègue, E and Barrière, F}, title = {Electrografted anthraquinone to monitor pH at the biofilm-anode interface in a wastewater microbial fuel cell.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {210}, number = {}, pages = {112274}, doi = {10.1016/j.colsurfb.2021.112274}, pmid = {34894599}, issn = {1873-4367}, mesh = {Anthraquinones ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; Hydrogen-Ion Concentration ; Wastewater ; }, abstract = {Electrografted anthraquinone on graphite was used as a probe to monitor the pH change at the biofilm-electrode interface at the anode of a microbial fuel cell inoculated with wastewater. The grafting procedure was optimized so that the pH-dependent electrochemical response of the grafted quinone did not overlay with that of the electroactive biofilm. The variation of the formal potential of the grafted quinone as a function of pH was linear over the pH range 1-10 with a slope of - 64 mV. This allowed to monitor the interfacial pH change over three weeks of biofilm colonization of the electrode. During that time the interfacial pH decreased from neutrality to 5.3 while the anolyte only acidified down to pH 6.2. This finding is relevant as local pH change usually leads to alterations of the bioenergetics process of microbial communities and hence on the performance of bioelectrochemical devices.}, } @article {pmid34893687, year = {2021}, author = {Nima, G and Harth-Chu, E and Hiers, RD and Pecorari, VGA and Dyer, DW and Khajotia, SS and Giannini, M and Florez, FLE}, title = {Antibacterial efficacy of non-thermal atmospheric plasma against Streptococcus mutans biofilm grown on the surfaces of restorative resin composites.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {23800}, pmid = {34893687}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Composite Resins ; Luminescent Measurements/methods ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Plasma Gases/*pharmacology ; Streptococcus mutans/*drug effects/ultrastructure ; Surface Properties ; Time Factors ; }, abstract = {The aim of this study was to evaluate the antimicrobial efficacy of non-thermal atmospheric plasma (NTAP) against Streptococcus mutans biofilms. Resin discs were fabricated, wet-polished, UV sterilized, and immersed in water for monomer extraction (37 °C, 24 h). Biofilms of bioluminescent S. mutans strain JM10 was grown on resin discs in anaerobic conditions for (37 °C, 24 h). Discs were divided into seven groups: control (CON), 2% chlorhexidine (CHX), only argon gas 150 s (ARG) and four NTAP treatments (30 s, 90 s, 120 s, 150 s). NTAP was applied using a plasma jet device. After treatment, biofilms were analyzed through the counting of viable colonies (CFU), bioluminescence assay (BL), scanning electron microscopy (SEM), and polymerase chain reaction (PCR). All NTAP-treated biofilm yielded a significant CFU reduction when compared to ARG and CON. BL values showed that NTAP treatment for 90 s, 120 s or 150 s resulted in statistically significantly lower metabolic activity when compared to the other groups. CHX displayed the lowest means of CFU and BL. SEM showed significant morphological changes in NTAP-treated biofilm. PCR indicated damage to the DNA structure after NTAP treatment. NTAP treatment was effective in lowering the viability and metabolism of S. mutans in a time-dependent manner, suggesting its use as an intraoral surface-decontamination strategy.}, } @article {pmid34893285, year = {2022}, author = {Phuangkaew, T and Booranabunyat, N and Kiatkamjornwong, S and Thanyasrisung, P and Hoven, VP}, title = {Amphiphilic quaternized chitosan: Synthesis, characterization, and anti-cariogenic biofilm property.}, journal = {Carbohydrate polymers}, volume = {277}, number = {}, pages = {118882}, doi = {10.1016/j.carbpol.2021.118882}, pmid = {34893285}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Carbohydrate Conformation ; Chitosan/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Particle Size ; Streptococcus mutans/*drug effects ; Surface-Active Agents/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Hydrophobized chitosan derivatives, hexyl chitosan (HCS), dodecyl chitosan (DCS), and phthaloyl chitosan (PhCS) of approximately 30 and 50% degree of substitution (%DS) reacted with glycidyltrimethylammonium chloride (GTMAC) to incorporate hydrophilic positively charged groups of N-[(2-hydroxyl-3-trimethylammonium)propyl] and yielded amphiphilic quaternized chitosan derivatives. They can assemble into spherical nanoparticles with a hydrodynamic diameter of ~100-300 nm and positive ζ-potential values (+15 to +56). Their anti-biofilm efficacy was evaluated against the dental caries pathogen, Streptococcus mutans. Among all derivatives, the one having 30%DS of hexyl group and prepared by reacting with 1 mol equivalent of GTMAC (H30CS-GTMAC) showed the best performance in terms of its aqueous solubility, the lowest minimum inhibitory concentration (138 μg/mL) and the minimum bactericidal concentration (275 μg/mL) which are superior to the unmodified chitosan. Its equivalent anti-biofilm efficacy to that of chlorhexidine suggests that it can be a greener antibacterial agent for oral care formulations.}, } @article {pmid34890712, year = {2022}, author = {Alcaraz, E and Ghiglione, B and Pineda, MV and Mangano, A and Di Conza, J and Passerini de Rossi, B}, title = {AmpR is a dual regulator in Stenotrophomonas maltophilia with a positive role in β-lactam resistance and a negative role in virulence, biofilm and DSF production.}, journal = {Research in microbiology}, volume = {173}, number = {3}, pages = {103917}, doi = {10.1016/j.resmic.2021.103917}, pmid = {34890712}, issn = {1769-7123}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Stenotrophomonas maltophilia/genetics ; Virulence ; beta-Lactam Resistance/genetics ; beta-Lactamases/genetics ; }, abstract = {Stenotrophomonas maltophilia intrinsic resistance to β-lactams is mediated by two chromosomal β-lactamases, L1 and L2, whose induction depends on AmpR. Its quorum sensing (QS) signal, the diffusible signal factor (DSF), has a positive role in biofilm production, virulence and induction of β-lactamases. We hypothesized that AmpR has a role in virulence, biofilm production and QS system. Studies were done on S. maltophilia K279a, K279a ampR[FS] (ampR deficient mutant) and K279aM11 (constitutively active AmpR mutant). K279a ampR[FS] showed the highest biofilm biomass, thickness and 3D organization. Conversely, K279aM11 was the least efficient biofilm former strain. qRT-PCR showed that spgM, related to biofilm formation and virulence, was upregulated in K279a ampR[FS] and downregulated in K279aM11. A constitutively active AmpR led to a reduction of DSF production, while K279a ampR[FS] was the highest producer. Consequently, qRT-PCR showed that AmpR negatively regulated rpfF expression. K279a ampR[FS] presented the highest oxidative stress resistance, overexpressed sodA gene and showed the highest virulence in the Galleria mellonella killing assay. This is the first evidence of the function of AmpR as a dual regulator in S. maltophilia with a positive role in β-lactam resistance and a negative role in DSF production, biofilm formation, oxidative stress resistance and virulence.}, } @article {pmid34890609, year = {2022}, author = {Zhang, X and Lin, T and Jiang, F and Zhang, X and Wang, S and Zhang, S}, title = {Impact of pipe material and chlorination on the biofilm structure and microbial communities.}, journal = {Chemosphere}, volume = {289}, number = {}, pages = {133218}, doi = {10.1016/j.chemosphere.2021.133218}, pmid = {34890609}, issn = {1879-1298}, mesh = {Biofilms ; Chlorine ; *Disinfectants ; *Drinking Water ; Halogenation ; *Microbiota ; Water Microbiology ; Water Supply ; }, abstract = {Pipe material and residual chlorine are key factors for the drinking water distribution system, and understanding the biofilm ecosystem is vital for water quality safeguard. The aim of our study was to determine the influence of pipe materials (ductile iron, steel, polyethylene) and chlorination on the biofilm structure and microbial community, as shown by the physicochemical properties, extracellular polymeric substances (EPS) structural characteristics, bacterial community composition, and functional traits. EPS spatial properties were studied based on a semi-quantitative confocal laser scanning microscope (CLSM) description. Regarding the impact of chlorination, residule chlorine (1.0 ± 0.3 mg L[-1] free chlorine) could inhibit the bacteria colonization, and initiate a potential response to external disinfectants revealed by the EPS spatial distribution changes and communities variation compared to unchlorinated system. Regarding the impact of pipe material, polyethylene (PE) biofilms displayed lower biomass, loose zoogloea structure, lower proteins and polysaccharides content, and poor microbial diversity in contrast to ductile iron and steel biofilms. Pipe material was the more possible driving factor of the biofilm community composition compared to the chlorination based on principal coordinates analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA). Actinobacteria was dominant in the PE biofilms (45.57%-83.32%), while Alphaproteobacteria (34.30%-73.22%) and Gammaproteobacteria (6.46%-36.82%) were the major classes in the steel and ductile iron biofilms. The genus Rhodococcus was predominant in the PE biofilms. Rhodococcus, Pseudomonas, and Sphingomonas seemed to have a better growth advantage in the chlorinated system and display a stronger disinfectant resistance. Functional sketch prediction indicated the potential impact of pipe material and chlorination on functional pathway abundnce, possible functional pathways associated with infectious disease included. This study provides insights into the impact of pipe material and chlorination on biofilm structure and microbial community and might help to develop monitoring or maintenance strategies to protect the biosafety of the drinking water.}, } @article {pmid34889984, year = {2022}, author = {Hage, M and Khelissa, S and Akoum, H and Chihib, NE and Jama, C}, title = {Cold plasma surface treatments to prevent biofilm formation in food industries and medical sectors.}, journal = {Applied microbiology and biotechnology}, volume = {106}, number = {1}, pages = {81-100}, pmid = {34889984}, issn = {1432-0614}, mesh = {Bacteria ; Bacterial Adhesion ; Biofilms ; Food Industry ; *Plasma Gases/pharmacology ; }, abstract = {Environmental conditions in food and medical fields enable the bacteria to attach and grow on surfaces leading to resistant bacterial biofilm formation. Indeed, the first step in biofilm formation is the bacterial irreversible adhesion. Controlling and inhibiting this adhesion is a passive approach to fight against biofilm development. This strategy is an interesting path in the inhibition of biofilm formation since it targets the first step of biofilm development. Those pathogenic structures are responsible for several foodborne diseases and nosocomial infections. Therefore, to face this public health threat, researchers employed cold plasma technologies in coating development. In this review, the different factors influencing the bacterial adhesion to a substrate are outlined. The goal is to present the passive coating strategies aiming to prevent biofilm formation via cold plasma treatments, highlighting antiadhesive elaborated surfaces. General aspects of surface treatment, including physico-chemical modification and application of cold plasma technologies, were also presented. KEY POINTS: • Factors surrounding pathogenic bacteria influence biofilm development. • Controlling bacterial adhesion prevents biofilm formation. • Materials can be coated via cold plasma to inhibit bacterial adhesion.}, } @article {pmid34888483, year = {2021}, author = {Hayashi, M and Kaneko, H and Yamada, T and Ikoshi, H and Noguchi, N and Nakaminami, H}, title = {Chinese herbal medicines and nutraceuticals inhibit Pseudomonas aeruginosa biofilm formation.}, journal = {Access microbiology}, volume = {3}, number = {8}, pages = {000254}, pmid = {34888483}, issn = {2516-8290}, abstract = {Pseudomonas aeruginosa is a major biofilm-forming, opportunistic pathogen. Tolerance to antimicrobial agents due to biofilm formation may lead to the emergence of antimicrobial-resistant bacterial strains. Thus, adjunctive agents that can inhibit biofilm formation are necessary to enhance the therapeutic efficacy of antimicrobial agents. In this study, we evaluated the anti-biofilm formation activity of selected Chinese herbal medicines and nutraceuticals, which are commercially available in Japan. Among the eight agents evaluated for their potential to inhibit biofilm formation, Eiekikaryu S, Iribakuga and Hyakujunro significantly reduced P. aeruginosa biofilm formation (P <0.05) without inhibiting bacterial growth. Additionally, the expression of biofilm-associated genes (rhlR, rhlA and lasB) in P. aeruginosa was significantly suppressed by Eiekikaryu S, Iribakuga and Hyakujunro (P <0.001). Our findings indicate that some Chinese herbal medicines and nutraceuticals can be potential adjunctive agents for antimicrobial therapy against P. aeruginosa .}, } @article {pmid34888261, year = {2021}, author = {Short, B and Delaney, C and McKloud, E and Brown, JL and Kean, R and Litherland, GJ and Williams, C and Martin, SL and MacKay, WG and Ramage, G}, title = {Investigating the Transcriptome of Candida albicans in a Dual-Species Staphylococcus aureus Biofilm Model.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {791523}, pmid = {34888261}, issn = {2235-2988}, support = {BB/P504567/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms ; *Candida albicans/genetics ; Hyphae ; *Staphylococcus aureus/genetics ; Transcriptome ; }, abstract = {Candida albicans is an opportunistic pathogen found throughout multiple body sites and is frequently co-isolated from infections of the respiratory tract and oral cavity with Staphylococcus aureus. Herein we present the first report of the effects that S. aureus elicits on the C. albicans transcriptome. Dual-species biofilms containing S. aureus and C. albicans mutants defective in ALS3 or ECE1 were optimised and characterised, followed by transcriptional profiling of C. albicans by RNA-sequencing (RNA-seq). Altered phenotypes in C. albicans mutants revealed specific interaction profiles between fungus and bacteria. The major adhesion and virulence proteins Als3 and Ece1, respectively, were found to have substantial effects on the Candida transcriptome in early and mature biofilms. Despite this, deletion of ECE1 did not adversely affect biofilm formation or the ability of S. aureus to interact with C. albicans hyphae. Upregulated genes in dual-species biofilms corresponded to multiple gene ontology terms, including those attributed to virulence, biofilm formation and protein binding such as ACE2 and multiple heat-shock protein genes. This shows that S. aureus pushes C. albicans towards a more virulent genotype, helping us to understand the driving forces behind the increased severity of C. albicans-S. aureus infections.}, } @article {pmid34888215, year = {2021}, author = {Gerayelou, G and Khameneh, B and Malaekeh-Nikouei, B and Mahmoudi, A and Fazly Bazzaz, BS}, title = {Dual Antibiotic and Diffusible Signal Factor Combination Nanoliposomes for Combating Staphylococcus epidermidis Biofilm.}, journal = {Advanced pharmaceutical bulletin}, volume = {11}, number = {4}, pages = {684-692}, pmid = {34888215}, issn = {2228-5881}, abstract = {Purpose: Microbial biofilms are one of the main causes of persistent human infections. Encapsulation of an antibiotic and a biofilm dispersal agent within a nano-carrier has been recognized as a novel approach to combat the problem of biofilm-related infections. Here, we develop the nanoliposomal formulation for delivery of vancomycin in combination with cis-2- decenoic acid (C2DA), to Staphylococcus epidermidis biofilm. The effects of the formulations were studied at two stages: biofilm growth inhabitation and biofilm eradication. Methods: Liposomal formulations were prepared by the solvent evaporation dehydration-rehydration method and were evaluated for size, zeta potential, and encapsulation efficacy. The ability of different agents in free and encapsulated forms were assessed to evaluate the anti-biofilm activities. Results: Vancomycin and C2DA were successfully co-encapsulated in the same nanoliposome (liposomal combination). The zeta potential values of the liposomal formulations of vancomycin, C2DA, and the liposomal combination were 37.2, 40.2, 51.5 mV, and the mean sizes of these liposomal formulations were 167.8±1.5, 215.5±8.8, 235.5±0.01, respectively. Encapsulation efficacy of C2DA was 65% and about 40% for vancomycin. The results indicated that liposomal combination exerted strong anti-biofilm activities, slightly exceeding those observed by the free form of a combination of vancomycin and C2DA, but higher than either agent used alone in their free forms. The anti-biofilm activity of formulations followed concentration and time-dependent manner. Conclusion: The combination of vancomycin and C2DA could inhibit biofilm formation. Employing the liposomal combination is a considerable method to remove bacterial biofilm.}, } @article {pmid34886838, year = {2021}, author = {Mazloomirad, F and Hasanzadeh, S and Sharifi, A and Nikbakht, G and Roustaei, N and Khoramrooz, SS}, title = {Identification and detection of pathogenic bacteria from patients with hospital-acquired pneumonia in southwestern Iran; evaluation of biofilm production and molecular typing of bacterial isolates.}, journal = {BMC pulmonary medicine}, volume = {21}, number = {1}, pages = {408}, pmid = {34886838}, issn = {1471-2466}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biofilms ; Cross-Sectional Studies ; Female ; Gram-Negative Bacteria/genetics/isolation & purification ; Gram-Negative Bacterial Infections/*epidemiology ; Gram-Positive Bacteria/genetics/isolation & purification ; Gram-Positive Bacterial Infections/*epidemiology ; Healthcare-Associated Pneumonia/*epidemiology/*microbiology ; Humans ; Iran/epidemiology ; Male ; Middle Aged ; Polymerase Chain Reaction ; Young Adult ; }, abstract = {BACKGROUND: Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in intensive care units (ICUs). The present study aims to determine the prevalence of pathogenic bacteria, their biofilm formation, and molecular typing from patients with HAP in southwestern Iran.

METHODS: Fifty-eight patients with HAP participated in this cross-sectional study. Sputum and endotracheal aspirate were collected from each patient for isolation and detection of bacteria. Biofilm formation was evaluated using Congo red agar or Microtiter plate assay. The antimicrobial susceptibility patterns of the isolates were investigated. The multiplex polymerase chain reaction (M-PCR) technique was used to determine the Staphylococcal Cassette Chromosome mec (SCCmec) types of methicillin-resistant Staphylococcus aureus (MRSA) strains. All S. aureus isolates were typed using the agr typing method. A repetitive element sequence-based PCR (rep-PCR) typing method was used for typing of Gram-negative bacteria. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 15 and the chi-square test.

RESULTS: Bacteria were isolated in 52 (89.7%) of patients. Acinetobacter baumannii (A. baumannii) was the most prevalent organism (37%), followed by S. aureus, Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). Using the PCR method, 56 bacteria were detected. A. baumannii was the most prevalent (35.7%) organism. A. baumannii and P. aeruginosa were biofilm-producing. All Gram-negative isolates were colistin-sensitive, and most of the A. baumannii isolates were multidrug-resistant (MDR). MRSA was identified in 12 (80%) S. aureus isolates, and 91.6% of MRSA were SCCmec type III. The agr type III was the most predominant. The rep-PCR analysis showed seven different patterns in 20 A. baumannii, six patterns in 13 P. aeruginosa, and four patterns in 6 E. coli.

CONCLUSION: A. baumannii was more prevalent than S. aureus in ventilator-associated pneumonia (VAP), while S. aureus is a major pathogen in non-ventilator hospital-acquired pneumonia (NV-HAP), possibly due to the tendency of the former to aquatic environments. Based on the rep-PCR typing method, it was concluded that bacteria were transmitted from patients or healthcare workers among different wards. Colistin can be used as a treatment in Gram-negative MDR isolates.}, } @article {pmid34885775, year = {2021}, author = {Corbu, VM and Gheorghe, I and Marinaș, IC and Geană, EI and Moza, MI and Csutak, O and Chifiriuc, MC}, title = {Demonstration of Allium sativum Extract Inhibitory Effect on Biodeteriogenic Microbial Strain Growth, Biofilm Development, and Enzymatic and Organic Acid Production.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {23}, pages = {}, pmid = {34885775}, issn = {1420-3049}, support = {CNFIS-FDI-2021-0405//Fondul de Dezvoltare Instituţională/ ; }, mesh = {Antioxidants/pharmacology ; Bacteria/drug effects/*growth & development ; Biofilms/drug effects/*growth & development ; Carboxylic Acids/*metabolism ; Enzymes/*metabolism ; Fungi/drug effects/*growth & development ; Garlic/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Polyphenols/pharmacology ; Solubility ; }, abstract = {To the best of our knowledge, this is the first study demonstrating the efficiency of Allium sativum hydro-alcoholic extract (ASE) againstFigure growth, biofilm development, and soluble factor production of more than 200 biodeteriogenic microbial strains isolated from cultural heritage objects and buildings. The plant extract composition and antioxidant activities were determined spectrophotometrically and by HPLC-MS. The bioevaluation consisted of the qualitative (adapted diffusion method) and the quantitative evaluation of the inhibitory effect on planktonic growth (microdilution method), biofilm formation (violet crystal microtiter method), and production of microbial enzymes and organic acids. The garlic extract efficiency was correlated with microbial strain taxonomy and isolation source (the fungal strains isolated from paintings and paper and bacteria from wood, paper, and textiles were the most susceptible). The garlic extract contained thiosulfinate (307.66 ± 0.043 µM/g), flavonoids (64.33 ± 7.69 µg QE/g), and polyphenols (0.95 ± 0.011 mg GAE/g) as major compounds and demonstrated the highest efficiency against the Aspergillus versicolor (MIC 3.12-6.25 mg/mL), A. ochraceus (MIC: 3.12 mg/mL), Penicillium expansum (MIC 6.25-12.5 mg/mL), and A. niger (MIC 3.12-50 mg/mL) strains. The extract inhibited the adherence capacity (IIBG% 95.08-44.62%) and the production of cellulase, organic acids, and esterase. This eco-friendly solution shows promising potential for the conservation and safeguarding of tangible cultural heritage, successfully combating the biodeteriogenic microorganisms without undesirable side effects for the natural ecosystems.}, } @article {pmid34885675, year = {2021}, author = {Konieczny, M and Rhein, P and Czaczyk, K and Białas, W and Juzwa, W}, title = {Imaging Flow Cytometry to Study Biofilm-Associated Microbial Aggregates.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {23}, pages = {}, pmid = {34885675}, issn = {1420-3049}, mesh = {Bacteria/*chemistry/genetics ; Biofilms/*growth & development ; Flow Cytometry ; Food Handling ; *Food Microbiology ; High-Throughput Screening Assays ; }, abstract = {The aim of the research was to design an advanced analytical tool for the precise characterization of microbial aggregates from biofilms formed on food-processing surfaces. The approach combined imaging flow cytometry with a machine learning-based interpretation protocol. Biofilm samples were collected from three diagnostic points of the food-processing lines at two independent time points. The samples were investigated for the complexity of microbial aggregates and cellular metabolic activity. Thus, aggregates and singlets of biofilm-associated microbes were simultaneously examined for the percentages of active, mid-active, and nonactive (dead) cells to evaluate the physiology of the microbial cells forming the biofilm structures. The tested diagnostic points demonstrated significant differences in the complexity of microbial aggregates. The significant percentages of the bacterial aggregates were associated with the dominance of active microbial cells, e.g., 75.3% revealed for a mushroom crate. This confirmed the protective role of cellular aggregates for the survival of active microbial cells. Moreover, the approach enabled discriminating small and large aggregates of microbial cells. The developed tool provided more detailed characteristics of bacterial aggregates within a biofilm structure combined with high-throughput screening potential. The designed methodology showed the prospect of facilitating the detection of invasive biofilm forms in the food industry environment.}, } @article {pmid34884908, year = {2021}, author = {Zarif, ME and Yehia, SA and Biță, B and Sătulu, V and Vizireanu, S and Dinescu, G and Holban, AM and Marinescu, F and Andronescu, E and Grumezescu, AM and Bîrcă, AC and Farcașiu, AT}, title = {Atmospheric Pressure Plasma Activation of Hydroxyapatite to Improve Fluoride Incorporation and Modulate Bacterial Biofilm.}, journal = {International journal of molecular sciences}, volume = {22}, number = {23}, pages = {}, pmid = {34884908}, issn = {1422-0067}, mesh = {Atmospheric Pressure ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/drug effects ; Durapatite/*chemistry ; Escherichia coli/drug effects/physiology ; Fluorides/chemistry/*pharmacology ; Hydrogen-Ion Concentration ; Microbial Viability/drug effects ; Plasma Gases/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/physiology ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Despite the technological progress of the last decade, dental caries is still the most frequent oral health threat in children and adults alike. Such a condition has multiple triggers and is caused mainly by enamel degradation under the acidic attack of microbial cells, which compose the biofilm of the dental plaque. The biofilm of the dental plaque is a multispecific microbial consortium that periodically develops on mammalian teeth. It can be partially removed through mechanical forces by individual brushing or in specialized oral care facilities. Inhibition of microbial attachment and biofilm formation, as well as methods to strengthen dental enamel to microbial attack, represent the key factors in caries prevention. The purpose of this study was to elaborate a cold plasma-based method in order to modulate microbial attachment and biofilm formation and to improve the retention of fluoride (F[-]) in an enamel-like hydroxyapatite (HAP) model sample. Our results showed improved F retention in the HAP model, which correlated with an increased antimicrobial and antibiofilm effect. The obtained cold plasma with a dual effect exhibited through biofilm modulation and enamel strengthening through fluoridation is intended for dental application, such as preventing and treating dental caries and enamel deterioration.}, } @article {pmid34884499, year = {2021}, author = {Wang, S and Feng, Y and Han, X and Cai, X and Yang, L and Liu, C and Shen, L}, title = {Inhibition of Virulence Factors and Biofilm Formation by Wogonin Attenuates Pathogenicity of Pseudomonas aeruginosa PAO1 via Targeting pqs Quorum-Sensing System.}, journal = {International journal of molecular sciences}, volume = {22}, number = {23}, pages = {}, pmid = {34884499}, issn = {1422-0067}, support = {31770152//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics/metabolism ; Biofilms/drug effects/growth & development ; Brassica/drug effects/microbiology ; Caenorhabditis elegans/*drug effects/microbiology ; Drosophila melanogaster/*drug effects/microbiology ; Flavanones/*pharmacology ; Gene Expression Regulation, Bacterial ; Pseudomonas Infections/microbiology/pathology/*prevention & control ; Pseudomonas aeruginosa/*pathogenicity ; *Quorum Sensing ; Virulence Factors/*antagonists & inhibitors/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa, an important opportunistic pathogen, is capable of producing various virulence factors and forming biofilm that are regulated by quorum sensing (QS). It is known that targeting virulence factor production and biofilm formation instead of exerting selective pressure on growth such as conventional antibiotics can reduce multidrug resistance in bacteria. Therefore, many quorum-sensing inhibitors (QSIs) have been developed to prevent or treat this bacterial infection. In this study, wogonin, as an active ingredient from Agrimonia pilosa, was found to be able to inhibit QS system of P. aeruginosa PAO1. Wogonin downregulated the expression of QS-related genes and reduced the production of many virulence factors, such as elastase, pyocyanin, and proteolytic enzyme. In addition, wogonin decreased the extracellular polysaccharide synthesis and inhibited twitching, swimming, and swarming motilities and biofilm formation. The attenuation of pathogenicity in P. aeruginosa PAO1 by wogonin application was further validated in vivo by cabbage infection and fruit fly and nematode survival experiments. Further molecular docking analysis, pathogenicity examination of various QS-related mutants, and PQS signal molecule detection revealed that wogonin could interfere with PQS signal molecular synthesis by affecting pqsA and pqsR. Taken together, the results indicated that wogonin might be used as an anti-QS candidate drug to attenuate the infection caused by P. aeruginosa.}, } @article {pmid34884339, year = {2021}, author = {Kozak, U and Lasota, A and Chałas, R}, title = {Changes in Distribution of Dental Biofilm after Insertion of Fixed Orthodontic Appliances.}, journal = {Journal of clinical medicine}, volume = {10}, number = {23}, pages = {}, pmid = {34884339}, issn = {2077-0383}, abstract = {Good oral hygiene is an important factor in oral and general health, especially in orthodontic patients, because fixed appliances might impede effective oral hygiene and thus increase the risks of tooth decay, periodontal disease and general health complications. This study investigated the impact of fixed orthodontic appliances on the distribution of dental biofilm in teenagers. Supragingival plaque was assessed at T0, T1 and T2. The distribution of the biofilm was analyzed. Approximal Plaque Index (API) and Bonded Bracket Index (BBI) were used to measure the presence of dental plaque. After insertion of the fixed appliance, the dental plaque indices values in the orthodontically treated group were significantly higher (p < 0.05) than in the control group. Fixed orthodontic appliances caused significant changes in the distribution of the biofilm. This was characterized by the change of location of the dental plaque. In the orthodontic group, we observed an increase in the amount of the supragingival plaque on the vestibular surface of the teeth.}, } @article {pmid34882220, year = {2022}, author = {Tao, H and Liao, Q and Xu, YI and Wang, HL}, title = {Efficacy of Slightly Acidic Electrolyzed Water for Inactivation of Cronobacter sakazakii and Biofilm Cells.}, journal = {Journal of food protection}, volume = {85}, number = {3}, pages = {511-517}, doi = {10.4315/JFP-21-263}, pmid = {34882220}, issn = {1944-9097}, mesh = {Biofilms ; *Cronobacter sakazakii ; Disinfection/methods ; Electrolysis ; Water/pharmacology ; }, abstract = {ABSTRACT: The disinfection efficacy and mechanism of activity of slightly acidic electrolyzed water (SAEW) were investigated against Cronobacter sakazakii. Treatment with three concentrations of SAEW decreased C. sakazakii by 23 to 55% after 2 min. Propidium iodide uptake and scanning electron micrographs indicated that SAEW treatment damaged cell integrity and changed membrane permeability resulting in leakage of nucleic acids (109.7%), intercellular proteins (692.3%), and potassium ions (53.6%). The ability to form biofilms was also reduced. SAEW treatment reduced the activity of superoxide dismutase and catalase from 100.73 and 114.18 U/mg protein to 50.03 and 50.13 U/mg protein, respectively. Expression of C. sakazakii response regulator genes (katG, rpoS, phoP, glpK, dacC, and CSK29544_RS05515) was reduced, which blocked repair of osmotic stress-induced damage and inhibited biofilm formation. These findings provide insight into the effects of SAEW on bacterial genotype and phenotype.}, } @article {pmid34879520, year = {2022}, author = {Zhang, G and Yang, Z and Zhou, Y and Zhu, DZ and Zhang, Y and Yu, T and Shypanski, A}, title = {Combination of nitrate and sodium nitroprusside dosing for sulfide control with low carbon source loss in sewer biofilm reactors.}, journal = {Journal of hazardous materials}, volume = {424}, number = {Pt B}, pages = {127527}, doi = {10.1016/j.jhazmat.2021.127527}, pmid = {34879520}, issn = {1873-3336}, mesh = {Biofilms ; *Carbon ; *Nitrates ; Nitroprusside ; Oxidation-Reduction ; Sulfides ; }, abstract = {Nitrate has been widely used in sewer systems for sulfide control. However, significant chemical consumption and the loss of carbon source were observed in previous studies. To find a feasible and cost-effective control strategy of the sulfide control, the effect of nitrate combined with sodium nitroprusside (SNP) dosage strategy was tested in lab-scale sewer biofilm reactors. Results showed that nitrate and SNP were strongly synergistic, with 30 mg N/L nitrate and 20 mg/L SNP being sufficient for sulfide control in this study. While large amount of nitrate alone (100 mg N/L) is required to achieve the same sulfide control effectiveness. Meanwhile, the nitrate combined with SNP could reduce the organic carbon source loss by 80%. Additionally, the high-throughput sequencing results showed that the relative abundance of autotrophic, nitrate reducing-sulfide oxidizing bacteria genera (a-NR-SOB) such as Arcobacter and Sulfurimonas was increased by around 18%, while the heterotrophic, nitrate-reducing bacteria (hNRB) such as Thauera was substantially reduced. It demonstrated that the sulfide control was mainly due to the a-NR-SOB activity under the nitrate and SNP dosing strategy. The microbial functional prediction further revealed that nitrate and SNP promoted the dissimilatory nitrate reduction process which utilizes sulfide as an effective electron donor. Moreover, economic assessment indicated that using the combination of nitrate and SNP for sulfide control in sewers would lower the chemical costs by approximately 35% compared with only nitrate addition.}, } @article {pmid34879504, year = {2022}, author = {He, S and Jia, M and Xiang, Y and Song, B and Xiong, W and Cao, J and Peng, H and Yang, Y and Wang, W and Yang, Z and Zeng, G}, title = {Biofilm on microplastics in aqueous environment: Physicochemical properties and environmental implications.}, journal = {Journal of hazardous materials}, volume = {424}, number = {Pt B}, pages = {127286}, doi = {10.1016/j.jhazmat.2021.127286}, pmid = {34879504}, issn = {1873-3336}, mesh = {Biofilms ; Environmental Monitoring ; *Microplastics ; Plastics/toxicity ; *Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {The excellent properties of plastics make them widely used all over the world. However, when plastics enter the environmental medium, microplastics will inevitably be produced due to physical, chemical and biological factors. Studies have shown that microplastics have been detected in terrestrial, aquatic and atmospheric environments. In addition, the presence of microplastics will provide a new artificial adhesion substrate for biofilms. It has been proved that the formation of biofilms could significantly change some properties of microplastics. Some studies have found that microplastics attached with biofilms have higher environmental risks and eco-toxicity. Therefore, considering the widespread existence of microplastics and the ecological risks of microplastic biofilms, the physical and chemical properties of biofilms on microplastics and their impact on microplastics in aqueous environment are worth reviewing. In this paper, we comprehensively reviewed representative studies in this area. Firstly, this study reviews that the existence of biofilms could change the transport and deposition of microplastics. Subsequently, the presence of biofilms would enhance the ability of microplastics to accumulate pollutant, such as persistent organic pollutants, heavy metals and antibiotics. Moreover, the effect of biofilms on microplastics enrichment of harmful microorganisms is summarized. Finally, some future research needs and strategies are proposed to better understand the problem of biofilms on microplastics.}, } @article {pmid34878811, year = {2022}, author = {Harrington, NE and Littler, JL and Harrison, F}, title = {Transcriptome Analysis of Pseudomonas aeruginosa Biofilm Infection in an Ex Vivo Pig Model of the Cystic Fibrosis Lung.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {3}, pages = {e0178921}, pmid = {34878811}, issn = {1098-5336}, support = {MR/R001898/1/MRC_/Medical Research Council/United Kingdom ; BB/M01116X/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Cystic Fibrosis ; Gene Expression Profiling ; Humans ; Lung ; *Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/genetics ; Quality of Life ; Swine ; }, abstract = {Pseudomonas aeruginosa is the predominant cause of chronic biofilm infections that form in the lungs of people with cystic fibrosis (CF). These infections are highly resistant to antibiotics and persist for years in the respiratory tract. One of the main research challenges is that current laboratory models do not accurately replicate key aspects of a P. aeruginosa biofilm infection, highlighted by previous RNA-sequencing studies. We compared the P. aeruginosa PA14 transcriptome in an ex vivo pig lung (EVPL) model of CF and a well-studied synthetic cystic fibrosis sputum medium (SCFM). P. aeruginosa was grown in the EVPL model for 1, 2, and 7 days, and in vitro in SCFM for 1 and 2 days. The RNA was extracted and sequenced at each time point. Our findings demonstrate that expression of antimicrobial resistance genes was cued by growth in the EVPL model, highlighting the importance of growth environment in determining accurate resistance profiles. The EVPL model created two distinct growth environments: tissue-associated biofilm and the SCFM surrounding tissue, each cuing a transcriptome distinct from that seen in SCFM in vitro. The expression of quorum sensing associated genes in the EVPL tissue-associated biofilm at 48 h relative to in vitro SCFM was similar to CF sputum versus in vitro conditions. Hence, the EVPL model can replicate key aspects of in vivo biofilm infection that are missing from other current models. It provides a more accurate P. aeruginosa growth environment for determining antimicrobial resistance that quickly drives P. aeruginosa into a chronic-like infection phenotype. IMPORTANCE Pseudomonas aeruginosa lung infections that affect people with cystic fibrosis are resistant to most available antimicrobial treatments. The lack of a laboratory model that captures all key aspects of these infections hinders not only research progression but also clinical diagnostics. We used transcriptome analysis to demonstrate how a model using pig lungs can more accurately replicate key characteristics of P. aeruginosa lung infection, including mechanisms of antibiotic resistance and infection establishment. Therefore, this model may be used in the future to further understand infection dynamics to develop novel treatments and more accurate treatment plans. This could improve clinical outcomes as well as quality of life for individuals affected by these infections.}, } @article {pmid34876576, year = {2021}, author = {Anbumani, S and da Silva, AM and Carvalho, IGB and Fischer, ER and de Souza E Silva, M and von Zuben, AAG and Carvalho, HF and de Souza, AA and Janissen, R and Cotta, MA}, title = {Controlled spatial organization of bacterial growth reveals key role of cell filamentation preceding Xylella fastidiosa biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {86}, pmid = {34876576}, issn = {2055-5008}, mesh = {Biofilms ; Humans ; Quorum Sensing ; *Silicon Dioxide ; *Xylella ; }, abstract = {The morphological plasticity of bacteria to form filamentous cells commonly represents an adaptive strategy induced by stresses. In contrast, for diverse human and plant pathogens, filamentous cells have been recently observed during biofilm formation, but their functions and triggering mechanisms remain unclear. To experimentally identify the underlying function and hypothesized cell communication triggers of such cell morphogenesis, spatially controlled cell patterning is pivotal. Here, we demonstrate highly selective cell adhesion of the biofilm-forming phytopathogen Xylella fastidiosa to gold-patterned SiO2 substrates with well-defined geometries and dimensions. The consequent control of both cell density and distances between cell clusters demonstrated that filamentous cell formation depends on cell cluster density, and their ability to interconnect neighboring cell clusters is distance-dependent. This process allows the creation of large interconnected cell clusters that form the structural framework for macroscale biofilms. The addition of diffusible signaling molecules from supernatant extracts provides evidence that cell filamentation is induced by quorum sensing. These findings and our innovative platform could facilitate therapeutic developments targeting biofilm formation mechanisms of X. fastidiosa and other pathogens.}, } @article {pmid34874074, year = {2022}, author = {Gutiérrez, DM and Castillo, Y and Ibarra-Avila, H and López, M and Orozco, JC and Lafaurie, GI and Castillo, DM}, title = {A new model for the formation of an Enterococcus faecalis endodontic biofilm with nutritional restriction.}, journal = {Journal of basic microbiology}, volume = {62}, number = {1}, pages = {13-21}, doi = {10.1002/jobm.202100533}, pmid = {34874074}, issn = {1521-4028}, support = {PCI-2017- 9443//Universidad El Bosque/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Biofilms ; *Enterococcus faecalis ; Microbial Viability ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; }, abstract = {An in vitro model for the formation of an Enterococcus faecalis endodontic biofilm under nutritional restriction was established, simulating clinical conditions for the evaluation of antimicrobial substances. Biofilm formation in dentin was standardized using root quarters incubated with E. faecalis ATCC 29212 at 37°C without nutritional changes. Biofilms were evaluated at 7, 14, and 30 days, counting bacterial colony-forming units using conventional culture and verified scanning electron microscopy. Bacterial viability and biovolume were determined with confocal laser microscopy. Colonization of E. faecalis and biofilm formation on the dentinal surface was confirmed after 7 and 14 days, respectively. Microorganism colonization was homogeneous over the entire root surface at each time point, without significant differences in the viability percentage and biovolume. On the contrary, a decrease in viability and an increase in biovolume were observed when the time was increased. Compared with other incubation times, 14 days was found to be the best time for the establishment of the biofilm in terms of biovolume and bacterial viability. This in vitro model for the formation of endodontic biofilm will allow future evaluation of the efficacy of antimicrobial substances with a more adequate clinical approach.}, } @article {pmid34873186, year = {2021}, author = {Jacob, B and Makarewicz, O and Hartung, A and Brodt, S and Roehner, E and Matziolis, G}, title = {In vitro additive effects of dalbavancin and rifampicin against biofilm of Staphylococcus aureus.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {23425}, pmid = {34873186}, issn = {2045-2322}, mesh = {Agar/chemistry ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; *Drug Synergism ; Glycopeptides/pharmacology ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; Polyethylene/chemistry ; Rifampin/*administration & dosage ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects ; Stem Cells ; Teicoplanin/administration & dosage/*analogs & derivatives ; Vancomycin/administration & dosage ; }, abstract = {Dalbavancin is a novel glycopeptide antibiotic approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). It is characterized by a potent activity against numerous Gram-positive pathogens, a long elimination half-life and a favorable safety profile. Most recently, its application for the treatment of periprosthetic joint infections (PJIs) was introduced. The aim of this study was to proof our hypothesis, that dalbavancin shows superior efficacy against staphylococcal biofilms on polyethylene (PE) disk devices compared with vancomycin and additive behavior in combination with rifampicin. Staphylococcus aureus biofilms were formed on PE disk devices for 96 h and subsequently treated with dalbavancin, vancomycin, rifampicin and dalbavancin-rifampicin combination at different concentrations. Quantification of antibacterial activity was determined by counting colony forming units (CFU/ml) after sonification of the PE, serial dilution of the bacterial suspension and plating on agar-plates. Biofilms were additionally life/dead-stained and visualized using fluorescence microscopy. Dalbavancin presented superior anti-biofilm activity compared to vancomycin. Additive effects of the combination dalbavancin and rifampicin were registered. Dalbavancin combined with rifampicin presents promising anti-biofilm activity characteristics in vitro. Further in vivo studies are necessary to establish recommendations for the general use of dalbavancin in the treatment of PJIs.}, } @article {pmid34872738, year = {2022}, author = {Nair, AR and Saratchandran, S and Gladstone, S and Ravindran, A}, title = {Letter to the editor in regard to the article "Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine".}, journal = {The Journal of prosthetic dentistry}, volume = {127}, number = {2}, pages = {373}, doi = {10.1016/j.prosdent.2021.08.016}, pmid = {34872738}, issn = {1097-6841}, mesh = {*Acrylic Resins ; Biofilms ; Caffeine ; *Candida albicans ; Denture Bases ; Nicotine ; }, } @article {pmid34871644, year = {2022}, author = {Amariei, G and Rosal, R and Fernández-Piñas, F and Koelmans, AA}, title = {Negative food dilution and positive biofilm carrier effects of microplastic ingestion by D. magna cause tipping points at the population level.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {294}, number = {}, pages = {118622}, doi = {10.1016/j.envpol.2021.118622}, pmid = {34871644}, issn = {1873-6424}, mesh = {Animals ; *Biofilms ; *Daphnia ; Eating ; *Microplastics/analysis ; *Water Pollutants, Chemical/analysis ; }, abstract = {Ingestion of microplastics by aquatic organisms is often harmful due to the dilution of their regular food with low-calorie microplastic particles, but can also be beneficial if nutritious biofilms are present on the microplastic surface. This begs the question: is ingestion of microplastic harmful or beneficial and can the net effect of the two mechanisms be quantified? Here, we quantified these harmful and beneficial effects on Daphnia magna, using dose-response tests with clean and biofouled microplastic respectively, and determined the trade-off between these counteracting effects. A population model was developed to calculate the isoclines for zero population growth, separating the regime where adverse food dilution dominated from that where the beneficial biofilm vector mechanism dominated. Our results show that the organisms grew better when exposed to biofouled microplastic compared to pristine microplastic. Very good model predictions (R[2] = 0.868-0.991) of the effects of biofouled microplastic were obtained based on literature parameter values, with optimization required only for the two sub-model parameters driving the dose-effect relationships for pristine microplastic. These results contradict previous sudies were only pristine microplastic were used and demonstrate that the ruling paradigm of unambiguously adverse microplastic effects is not ecologically justifiable.}, } @article {pmid34871207, year = {2021}, author = {Wei, J and Cao, X and Qian, J and Liu, Z and Wang, X and Su, Q and Wang, Y and Xie, R and Li, X}, title = {Evaluation of antimicrobial peptide LL-37 for treatment of Staphylococcus aureus biofilm on titanium plate.}, journal = {Medicine}, volume = {100}, number = {44}, pages = {e27426}, pmid = {34871207}, issn = {1536-5964}, mesh = {Alloys ; Antimicrobial Cationic Peptides/*pharmacology ; Antimicrobial Peptides/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Humans ; Microbial Sensitivity Tests ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects ; Titanium/*chemistry ; Cathelicidins ; }, abstract = {The antimicrobial peptide LL-37 belongs to the cathelicidin family and is one of the few human bactericidal peptides with potent antistaphylococcal activity. Staphylococcus aureus is one of the main infection bacteria in orthopedic implant therapy. Biofilm formation after bacterial infection brings more and more severe test for clinical antiinfection treatment.However, there are few studies on LL-37 in S. aureus infection of prosthesis. In this work, addition to research the antibacterial activity and the inhibitory effect on bacterial adhesion of LL-37, an in vitro model of S. aureus biofilm formation on titanium alloy surface was established to observe the inhibitory effect of LL-37.The results showed that LL-37 has a strong antibacterial effect on S. aureus in vitro, and the minimum inhibitory concentration (MIC) is about 0.62 μΜ. Moreover, LL-37 has significant impact on the adhesion of S. aureus when the concentration ≥0.16 μM and significant anti-staphylococcal biofilm effects on static biofilm models at the concentration of 0.31 to 10 μM. Additionally, LL-37 at 5 μM had a significant destructive effect on S. aureus biofilm (P < .05) that formed on the titanium alloy surface.This study further confirmed the role of LL-37 in the process of S. aureus infection, including antimicrobial activities, inhibition of bacterial adhesion, and inhibition of mature biofilm. LL-37 can significantly destroy the stable biofilm structure on the titanium alloy surface in vitro, which may provide a new way for refractory infection caused by S. aureus in titanium alloy prosthesis infection.}, } @article {pmid34870816, year = {2022}, author = {Liberti, A and Leigh, BA and Graham, Z and Natarajan, O and Dishaw, LJ}, title = {A Role for Secreted Immune Effectors in Microbial Biofilm Formation Revealed by Simple In Vitro Assays.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2421}, number = {}, pages = {127-140}, pmid = {34870816}, issn = {1940-6029}, mesh = {Animals ; Bacteria/metabolism ; *Biofilms ; Carrier Proteins ; Chitin/metabolism ; Fungi/metabolism ; *Microbiota ; Proteins ; Saccharomyces cerevisiae/metabolism ; }, abstract = {The formation of biofilms is critical for the successful and stable colonization of mucosal surfaces by microbes, which often build three-dimensional environments by exuding exopolysaccharides and other macromolecules such as proteins, lipids, and even DNA. It is not just bacteria, but fungi such as yeast, that form these adherent interacting communities. Historically, biofilms have been studied in the context of pathogenesis, but only recently it has been recognized that important relationships among members of host-associated microbiomes are maintained within the context of biofilms. Host immune responses impact biofilm formation in various ways; for example, it is likely that formation of stable biofilms by non-pathogens improves barrier defenses by not just filling available niche spaces but also by helping to ward off pathogens directly. Recently, it was found that soluble immune effector molecules such as immunoglobulin A (IgA) in mammals serve essential roles in modulating complex biofilm communities in ways that benefit the host. Additional lines of evidence from other secreted immune effectors, such as the variable region-containing chitin-binding proteins (VCBPs) in protochordates, now suggest that this phenomenon is much more widespread than previously recognized. The activity of these immune molecules also likely serves roles beyond those of simple defense strategies; rather, they may be improving the outcome of symbiotic interactions benefiting the host. Thus, traditional immune assays that are aimed at studying the function of secreted immune effectors, such as agglutination assays, should take into account the possibility that the first observation may not be the last if the microbes under study are not directly killed. Here, we describe a series of simple approaches to characterize biofilm formation when bacteria (or yeast) are cultured in the presence of a secreted immune effector. To model this approach, we use microbes isolated from the gut of Ciona robusta, each grown in the presence or absence of VCBPs. The approaches defined here are amenable to diverse model systems and their microbes.}, } @article {pmid34869542, year = {2021}, author = {Fratianni, F and d'Acierno, A and Ombra, MN and Amato, G and De Feo, V and Ayala-Zavala, JF and Coppola, R and Nazzaro, F}, title = {Fatty Acid Composition, Antioxidant, and in vitro Anti-inflammatory Activity of Five Cold-Pressed Prunus Seed Oils, and Their Anti-biofilm Effect Against Pathogenic Bacteria.}, journal = {Frontiers in nutrition}, volume = {8}, number = {}, pages = {775751}, pmid = {34869542}, issn = {2296-861X}, abstract = {Background/Aim: Sweet almond (Prunus amygdalus dulcis) oil is one of the most famous cold-pressed seed oils. However, other species of Prunus can provide oils with healthy properties. We analyzed the fatty acid (FA) composition, as well as the antioxidant, the in vitro anti-inflammatory properties, and the antibiofilm activity of five commercial vegetable cold-pressed seed oils of apricot, peach, plum, cherry, and black cherry. Methods: Gas Chromatography-Mass Spectrometry was performed for the analysis of FAs The antioxidant property of the oils was carried using different tests [2, 2-diphenyl-1-picrylhydrazyl (DPPH assay)], Ferric Reducing Antioxidant Power (FRAP), and the 2, 20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+). The denaturation assay performed on bovine serum albumin (BSA) was used to evaluate the in vitro anti-inflammatory activity. The anti-biofilm activity was assessed using five pathogenic strains, namely, Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, through the crystal violet test and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), used to evaluate the metabolism of the microbial cells present within the biofilm. Results: Oleic acid and linoleic acids were the most abundant FAs. Black cherry seed oil exhibited the best antioxidant activity, but in general, the amount of oil needed to inhibit the activity of 1 ml of DPPH assay at 50% did not exceed 10 μg. The extract concentration for the 50% inhibition of the denaturation of the protein (IC50) did not exceed 4.4 μg. Linoleic and stearic acids affected the antioxidant activity of the oils; oleic acid, linolenic, and palmitoleic acids exhibited beneficial effects in preserving the BSA denaturation, as shown by the correlation data. The oils were able to inhibit the biofilm formation of the pathogens (up to 71.40% of inhibition) as well as act against their mature biofilm, although with different strengths, with values up to 61.54%. Concurrently, they also acted on the pathogen metabolism. Conclusion: The oils represent a valuable source of some healthy FAs. They showed potential antioxidant and anti-inflammatory in vitro activity, in addition, their potential effect on the biofilm can offer important ideas for research and reflection on their use as functional foods and/or ingredients.}, } @article {pmid34869296, year = {2021}, author = {Dong, X and Overton, CM and Tang, Y and Darby, JP and Sun, YP and Yang, L}, title = {Visible Light-Activated Carbon Dots for Inhibiting Biofilm Formation and Inactivating Biofilm-Associated Bacterial Cells.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {786077}, pmid = {34869296}, issn = {2296-4185}, abstract = {This study aimed to address the significant problems of bacterial biofilms found in medical fields and many industries. It explores the potential of classic photoactive carbon dots (CDots), with 2,2'-(ethylenedioxy)bis (ethylamine) (EDA) for dot surface functionalization (thus, EDA-CDots) for their inhibitory effect on B. subtilis biofilm formation and the inactivation of B. subtilis cells within established biofilm. The EDA-CDots were synthesized by chemical functionalization of selected small carbon nanoparticles with EDA molecules in amidation reactions. The inhibitory efficacy of CDots with visible light against biofilm formation was dependent significantly on the time point when CDots were added; the earlier the CDots were added, the better the inhibitory effect on the biofilm formation. The evaluation of antibacterial action of light-activated EDA-CDots against planktonic B. subtilis cells versus the cells in biofilm indicate that CDots are highly effective for inactivating planktonic cells but barely inactivate cells in established biofilms. However, when coupling with chelating agents (e.g., EDTA) to target the biofilm architecture by breaking or weakening the EPS protection, much enhanced photoinactivation of biofilm-associated cells by CDots was achieved. The study demonstrates the potential of CDots to prevent the initiation of biofilm formation and to inhibit biofilm growth at an early stage. Strategic combination treatment could enhance the effectiveness of photoinactivation by CDots to biofilm-associated cells.}, } @article {pmid34869084, year = {2021}, author = {Fernández-Pereira, J and Alvarado, M and Gómez-Molero, E and Dekker, HL and Blázquez-Muñoz, MT and Eraso, E and Bader, O and de Groot, PWJ}, title = {Characterization of Awp14, A Novel Cluster III Adhesin Identified in a High Biofilm-Forming Candida glabrata Isolate.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {790465}, pmid = {34869084}, issn = {2235-2988}, mesh = {Biofilms ; Candida albicans ; *Candida glabrata/genetics ; *Candidiasis ; Fungal Proteins/genetics ; Humans ; }, abstract = {Candida glabrata is among the most prevalent causes of candidiasis. Unlike Candida albicans, it is not capable of changing morphology between yeast and hyphal forms but instead has developed other virulence factors. An important feature is its unprecedented large repertoire of predicted cell wall adhesins, which are thought to enable adherence to a variety of surfaces under different conditions. Here, we analyzed the wall proteome of PEU1221, a high biofilm-forming clinical strain isolated from an infected central venous catheter, under biofilm-forming conditions. This isolate shows increased incorporation of putative adhesins, including eight proteins that were not detected in walls of reference strain ATCC 2001, and of which Epa22, Awp14, and Awp2e were identified for the first time. The proteomics data suggest that cluster III adhesin Awp14 is relatively abundant in PEU1221. Phenotypic studies with awp14Δ deletion mutants showed that Awp14 is not responsible for the high biofilm formation of PEU1221 onto polystyrene. However, awp14Δ mutant cells in PEU1221 background showed a slightly diminished binding to chitin and seemed to sediment slightly slower than the parental strain suggesting implication in fungal cell-cell interactions. By structural modeling, we further demonstrate similarity between the ligand-binding domains of cluster III adhesin Awp14 and those of cluster V and VI adhesins. In conclusion, our work confirms the increased incorporation of putative adhesins, such as Awp14, in high biofilm-forming isolates, and contributes to decipher the precise role of these proteins in the establishment of C. glabrata infections.}, } @article {pmid34869073, year = {2021}, author = {Gaio, V and Lopes, N and Cerca, N and França, A}, title = {codY and pdhA Expression Is Induced in Staphylococcus epidermidis Biofilm and Planktonic Populations With Higher Proportions of Viable but Non-Culturable Cells.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {771666}, pmid = {34869073}, issn = {2235-2988}, mesh = {Biofilms ; Culture Media ; *Plankton ; *Staphylococcus epidermidis/genetics ; }, abstract = {Staphylococcus epidermidis biofilm cells can enter a physiological state known as viable but non-culturable (VBNC), where, despite being alive, they do not grow in conventional laboratory media. As such, the presence of VBNC cells impacts the diagnosis of S. epidermidis biofilm-associated infections. Previous transcriptomics analysis of S. epidermidis strain 9142 biofilms with higher proportions of VBNC cells suggested that the genes pdhA, codY and mazEF could be involved in the induction of the VBNC state. However, it was previously demonstrated that VBNC induction is strain-dependent. To properly assess the role of these genes in VBNC induction, the construction of mutant strains is necessary. Thus, herein, we assessed if VBNC cells could be induced in strain 1457, a strain amenable to genetic manipulation, and if the previously identified genes were involved in the modulation of the VBNC state in this strain. Furthermore, we evaluated the formation of VBNC cells on planktonic cultures. Our results showed that despite being commonly associated with biofilms, the proportion of VBNC cells can be modulated in both biofilm and planktonic cultures and that the expression of codY and pdhA was upregulated under VBNC inducing conditions in both phenotypes. Overall, our study revealed that the formation of VBNC cells in S. epidermidis is independent of the mode of growth and that the genes codY and pdhA seem to be relevant for the regulation of this physiological condition.}, } @article {pmid34868474, year = {2022}, author = {Roncari Rocha, G and Sims, KR and Xiao, B and Klein, MI and Benoit, DSW}, title = {Nanoparticle carrier co-delivery of complementary antibiofilm drugs abrogates dual species cariogenic biofilm formation in vitro.}, journal = {Journal of oral microbiology}, volume = {14}, number = {1}, pages = {1997230}, pmid = {34868474}, issn = {2000-2297}, support = {F31 DE026944/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; }, abstract = {BACKGROUND: Dental caries is a multifactorial disease caused by pathogenic biofilm. In particular, Streptococcus mutans synthesizes biofilm exopolysaccharides, while Candida albicans is associated with the development of severe carious lesions.

AIM: This study aimed to prevent the formation of S. mutans and C. albicans biofilms by exploiting pH-sensitive nanoparticle carriers (NPCs) with high affinity to exopolysaccharides to increase the substantivity of multi-targeted antibiofilm drugs introduced topically in vitro.

METHODS: Dual-species biofilms were grown on saliva-coated hydroxyapatite discs with sucrose. Twice-daily, 1.5 min topical treatment regimens of unloaded and drug-loaded NPC were used. Drugs included combinations of two or three compounds with distinct, complementary antibiofilm targets: tt-farnesol (terpenoid; bacterial acid tolerance, fungal quorum sensing), myricetin (flavonoid; exopolysaccharides inhibitor), and 1771 (lipoteichoic acid inhibitor; bacterial adhesion and co-aggregation). Biofilms were evaluated for biomass, microbial population, and architecture.

RESULTS: NPC delivering tt-farnesol and 1771 with or without myricetin completely prevented biofilm formation by impeding biomass accumulation, bacterial and fungal population growth, and exopolysaccharide matrix deposition (vs. control unloaded NPC). Both formulations hindered acid production, maintaining the pH of spent media above the threshold for enamel demineralization. However, treatments had no effect on pre-established dual-species biofilms.

CONCLUSION: Complementary antibiofilm drug-NPC treatments prevented biofilm formation by targeting critical virulence factors of acidogenicity and exopolysaccharides synthesis.}, } @article {pmid34867928, year = {2021}, author = {Thees, AV and Pietrosimone, KM and Melchiorre, CK and Marden, JN and Graf, J and Lynes, MA and Maltz-Matyschsyk, M}, title = {PmtA Regulates Pyocyanin Expression and Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {789765}, pmid = {34867928}, issn = {1664-302X}, abstract = {The opportunistic pathogen Pseudomonas aeruginosa expresses a small molecular weight, cysteine-rich protein (PmtA), identified as a metallothionein (MT) protein family member. The MT family proteins have been well-characterized in eukaryotes as essential for zinc and copper homeostasis, protection against oxidative stress, and the ability to modify a variety of immune activities. Bacterial MTs share sequence homology, antioxidant chemistry, and heavy metal-binding capacity with eukaryotic MTs, however, the impact of bacterial MTs on virulence and infection have not been well-studied. In the present study, we investigated the role of PmtA in P. aeruginosa PAO1 using a PmtA-deficient strain (ΔpmtA). Here we demonstrated the virulence factor, pyocyanin, relies on the expression of PmtA. We showed that PmtA may be protective against oxidative stress, as an alternative antioxidant, glutathione, can rescue pyocyanin expression. Furthermore, the expression of phzM, which encodes a pyocyanin precursor enzyme, was decreased in the ΔpmtA mutant during early stationary phase. Upregulated pmtA expression was previously detected in confluent biofilms, which are essential for chronic infection, and we observed that the ΔpmtA mutant was disrupted for biofilm formation. As biofilms also modulate antibiotic susceptibility, we examined the ΔpmtA mutant susceptibility to antibiotics and found that the ΔpmtA mutant is more susceptible to cefepime and ciprofloxacin than the wild-type strain. Finally, we observed that the deletion of pmtA results in decreased virulence in a waxworm model. Taken together, our results support the conclusion that PmtA is necessary for the full virulence of P. aeruginosa and may represent a potential target for therapeutic intervention.}, } @article {pmid34867886, year = {2021}, author = {Zhang, Z and Liang, Y and Yu, L and Chen, M and Guo, Y and Kang, Z and Qu, C and Tian, C and Zhang, D and Liu, M}, title = {TatD DNases Contribute to Biofilm Formation and Virulence in Trueperella pyogenes.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {758465}, pmid = {34867886}, issn = {1664-302X}, abstract = {TatD DNases are conserved proteins in a variety of organisms and are considered potential virulence factors in Plasmodium falciparum and Streptococcus pneumoniae. However, the function of TatD DNases has not yet been determined in Trueperella pyogenes, which causes various infections in animals and leads to economic losses. In this study, we describe the roles of TatD DNases in T. pyogenes (TpTatDs). A bioinformatics analysis was performed to investigate the sequence characteristics of TpTatDs, and then the ability of recombinant TatD proteins to hydrolyze DNA was determined in the presence of divalent cations. Moreover, we constructed tatD-deficient mutants. The biofilms formed by the wild-type and mutant strains were observed under a microscope. The mortality and bacterial load in the spleen of mice infected with the wild-type strain and tatD-deficient mutants were determined to obtain insights into the role of TatDs in the virulence of T. pyogenes. Two TatD DNases were identified in T. pyogenes. They were Mg[2+]-dependent DNases and exhibited DNA endonuclease activity. Compared with those formed by the parental strain, biofilms formed by mutants showed a significantly reduced thickness and biomass. Moreover, mutants produced a lower bacterial load in the spleen of mice and compromised virulence. Our data indicated that TatD DNases in T. pyogenes are involved in biofilm formation and required for virulence during infections.}, } @article {pmid34867884, year = {2021}, author = {Lee, D and Im, J and Park, DH and Jeong, S and Park, M and Yoon, S and Park, J and Han, SH}, title = {Lactobacillus plantarum Lipoteichoic Acids Possess Strain-Specific Regulatory Effects on the Biofilm Formation of Dental Pathogenic Bacteria.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {758161}, pmid = {34867884}, issn = {1664-302X}, abstract = {Bacterial biofilm residing in the oral cavity is closely related to the initiation and persistence of various dental diseases. Previously, we reported the anti-biofilm activity of Lactobacillus plantarum lipoteichoic acid (Lp.LTA) on a representative dental cariogenic pathogen, Streptococcus mutans. Since LTA structure varies in a bacterial strain-specific manner, LTAs from various L. plantarum strains may have differential anti-biofilm activity due to their distinct molecular structures. In the present study, we isolated Lp.LTAs from four different strains of L. plantarum (LRCC 5193, 5194, 5195, and 5310) and compared their anti-biofilm effects on the dental pathogens, including S. mutans, Enterococcus faecalis, and Streptococcus gordonii. All Lp.LTAs similarly inhibited E. faecalis biofilm formation in a dose-dependent manner. However, their effects on S. gordonii and S. mutans biofilm formation were different: LRCC 5310 Lp.LTA most effectively suppressed the biofilm formation of all strains of dental pathogens, while Lp.LTAs from LRCC 5193 and 5194 hardly inhibited or even enhanced the biofilm formation. Furthermore, LRCC 5310 Lp.LTA dramatically reduced the biofilm formation of the dental pathogens on the human dentin slice infection model. Collectively, these results suggest that Lp.LTAs have strain-specific regulatory effects on biofilm formation of dental pathogens and LRCC 5310 Lp.LTA can be used as an effective anti-biofilm agent for the prevention of dental infectious diseases.}, } @article {pmid34867864, year = {2021}, author = {Lin, Q and Pilewski, JM and Di, YP}, title = {Acidic Microenvironment Determines Antibiotic Susceptibility and Biofilm Formation of Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {747834}, pmid = {34867864}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is the most prevalent bacterial species that contribute to cystic fibrosis (CF) respiratory failure. The impaired function of CF transmembrane conductance regulator leads to abnormal epithelial Cl[-/]HCO3 [-] transport and acidification of airway surface liquid. However, it remains unclear why the CF lung is most commonly infected by Pseudomonas aeruginosa versus other pathogens. We carried out studies to investigate if lower pH helps Pseudomonas aeruginosa adapt and thrive in the CF-like acidic lung environment. Our results revealed that Pseudomonas aeruginosa generally forms more biofilm, induces antibiotic resistance faster in acidic conditions, and can be reversed by returning the acidic environment to physiologically neutral conditions. Pseudomonas aeruginosa appears to be highly adaptive to the CF-like acidic pH environment. By studying the effects of an acidic environment on bacterial response, we may provide a new therapeutic option in preventing chronic Pseudomonas aeruginosa infection and colonization.}, } @article {pmid34867063, year = {2021}, author = {Narenkumar, J and Devanesan, S and AlSalhi, MS and Kokilaramani, S and Ting, YP and Rahman, PKSM and Rajasekar, A}, title = {Biofilm formation on copper and its control by inhibitor/biocide in cooling water environment.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {12}, pages = {7588-7594}, pmid = {34867063}, issn = {1319-562X}, abstract = {The present study has successfully identified the nitrate reducing bacteria present in the cooling water system and also investigated the performance of industrially applied biocide and inhibitor on the bacterial inhibition. In order to carry out the objective of this study, facilities and methods such as 16S rRNA gene sequencing, Lowry assay, SEM, EIS, ICP-MS and weight loss analysis were being utilized. In this study, two out of the five morphologically dis- similar colonies identified through 16S rRNA gene sequencing, namely the Massilia timonae and the Pseudomonas, were being utilized in the biocorrosion study on copper metal. From the surface analysis using SEM demonstrated the phenomenon of biofilm formation on the copper surface. 2-methylbenzimidazole has the addition of methyl group in the diazole ring position of benzimidazole it has create basicity environment and inhibit the metal deterioration. Meanwhile, it is also deducible from the EIS and protein analysis that com- bination of biocide with either of the inhibitors gives rise to better biocorrosion suppression (0.00178 mpy and 0.00171mpy) as compared to the sole effect of either biocide or inhibitor (0.00219 mpy, 0.00162 and 0.00143). Biocorrosion system biocide with MBM was found to exhibit 65% corrosion inhibition efficiency. Moreover, adoption of 2-Methylbenzimidazole seems to display better performance as compared to Multionic 8151, which is adopted in cooling water system.}, } @article {pmid34867042, year = {2021}, author = {AlEraky, DM and Madi, M and El Tantawi, M and AlHumaid, J and Fita, S and AbdulAzeez, S and Borgio, JF and Al-Harbi, FA and Alagl, AS}, title = {Predominance of non-Streptococcus mutans bacteria in dental biofilm and its relation to caries progression.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {12}, pages = {7390-7395}, pmid = {34867042}, issn = {1319-562X}, abstract = {This study aims to assess differences in biofilm bacterial composition between patients with low and high caries. Patients without a medical problem and with no history of antibiotic use, mouth wash or fluoride application in the previous 3 months were recruited. Caries was recorded at cavitation level; score was calculated by a national mean (dmft of 4.8 and DMFT of 2.7). Pooled biofilm samples were collected from mesial, distal, buccal, lingual, and occlusal surfaces. Based on caries experience, individuals were classified into low and high caries and both groups were compared regarding bacteria identified using 16S rRNA gene sequencing, and molecular phylogenetic analysis of the isolates was performed. A total of twenty seven randomly selected samples with low (n = 13) and high (n = 14) caries. Identification of oral bacteria was performed using 16S rRNA sequence, Rothia mucilaginosa and R. aeria were identified in low caries individuals, while R. dentocariosa was detected in high caries individuals. Two Streptococcus spp. were identified only in low caries S. salivarius and S. gordonii whereas S. sanguinis, S. mitis, S. sinensis, S. rubneri, S. vestibularis, S. cristatus and S. massiliensis were identified only in individuals with high caries. This study revealed the absence of R. mucilaginosa in the high caries subjects and its coexistence with the low caries subjects. Streptococcus mutans was insignificant contributor of caries among samples, while, Streptococcus sanguinis was the main constituent of high caries Saudi patients.}, } @article {pmid34866993, year = {2021}, author = {Acharjee, M and Hoque, R and Shreya, SS and Tabassum, N and Acharjee, MR and Rezanujjaman, M and Rahman, M and Amin, A and Mahmud, MR}, title = {Antibiotic susceptibility pattern of fish pathogens: A new approach of emerging the bacterial resistance through biofilm formation in in-vitro condition.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {12}, pages = {6933-6938}, pmid = {34866993}, issn = {1319-562X}, abstract = {BACKGROUND: The ability of many bacteria to adhere on the host surfaces and forming biofilms has major implications in a wide variety of industries including the food industry, where biofilms may create a persistent source of contamination. In the same environmental condition, the multiple bacterial species can closely interact with each other and may easily enhance their drug resistance capability, which finally increases the multi-drug resistant (MDR) attribute of the species.

OBJECTIVE: The present study examined whether the mixed-species biofilm possesses any impact on the enhancement of the antibiotic resistance of the planktonic or single-cell bacterial isolates present in the fish samples.

METHODS: In this regard, Cyprinus rubrofuscus (Koi), Heteropneustes fossilis (Shing) and Mystus vittatus (Tengra) fishes were collected and subjected to form an in vitro biofilm by shaking condition into the wise bath. The drug-resistant pattern was determined by the Kirby Bauer technique.

RESULTS: All the samples exhibited a huge array (up to 10[7] cfu/ml or g) of bacteria such as E. coli, Klebsiella spp., Vibrio spp., Salmonella spp., Proteus spp. and Staphylococcus spp. The isolates from both the bulk samples and their corresponding biofilms were subjected to antibiogram assay using antibiotics such as Ampicillin (10 µg), Erythromycin (15 μg), Streptomycin (STP 10 μg), Oxacillin (10 µg), Nalidixic acid (30 µg). Before biofilm formation, few of the isolates were found to be sensitive and few were resistant against the antibiotics. But when the species were isolated from the biofilm the sensitive one acquired drug resistance and resistant strain unveiled more resistance towards the same antibiotics. The present study revealed extensive bacterial contamination in fish samples among those some were resistant against the supplied drugs.

CONCLUSION: After the formation of multi-species biofilm, the isolates became more resistant against the same drugs that is alarming for consumers and major obstacles to maintain sustainable health.}, } @article {pmid34866484, year = {2022}, author = {Kling, KE and Maddox, CW and Manfra Marretta, S and Nowicki, C and Schaeffer, DJ}, title = {Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog.}, journal = {Journal of veterinary dentistry}, volume = {39}, number = {1}, pages = {9-20}, doi = {10.1177/08987564211058496}, pmid = {34866484}, issn = {2470-4083}, mesh = {Actinomycetaceae ; Animals ; Biofilms ; Chlorhexidine/pharmacology ; *Dental Plaque/microbiology/therapy/veterinary ; *Dog Diseases/drug therapy ; Dogs ; Neisseria ; Porphyromonas ; }, abstract = {This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.}, } @article {pmid34866248, year = {2022}, author = {Virto, L and Simões-Martins, D and Sánchez, MC and Encinas, A and Sanz, M and Herrera, D}, title = {Antimicrobial effects of a new brushing solution concept on a multispecies in vitro biofilm model growing on titanium surfaces.}, journal = {Clinical oral implants research}, volume = {33}, number = {2}, pages = {209-220}, doi = {10.1111/clr.13884}, pmid = {34866248}, issn = {1600-0501}, support = {381/2019//Universidad Complutense de Madrid and bonyf AG (Vaduz, Liechtenstein), research contract/ ; }, mesh = {Aggregatibacter actinomycetemcomitans ; *Anti-Infective Agents ; Biofilms ; Fusobacterium nucleatum ; *Titanium/pharmacology ; }, abstract = {OBJECTIVES: To evaluate the antibiofilm and antibacterial effects of a new brushing solution concept, in a validated peri-implant biofilm model.

MATERIALS AND METHODS: A multispecies in vitro biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum, was used. To evaluate the antibiofilm capacity, titanium discs (Ti-SLA) were immersed in 1 ml of the tested solution (one tablet dissolved in warm water) for 2 min, prior and every 24 h during a 3-day biofilm development. Negative (water) and positive (0.12% chlorhexidine/0.05% cetylpyridinium chloride mouth rinse) controls treated discs were run in parallel. To evaluate the antibacterial effects, planktonic cells and 72-h biofilms on sterile Ti-SLA discs were exposed (2 min) to the mentioned treatments. Biofilm structure was analysed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Bacterial load was measured by quantitative polymerase chain reaction and by culture in planktonic cells.

RESULTS: The tested product showed antibiofilm effects, impacting on the 48-h and 72-h biofilm thickness and significantly reducing viability of all bacterial species, except A. actinomycetemcomitans. Antibacterial effects were observed against the six bacterial species in planktonic state and in 72-h biofilms, especially for F. nucleatum and A. actinomycetemcomitans.

CONCLUSION: The tested brushing solution demonstrated antibacterial and antibiofilm properties, mainly against the peri-implant pathogens included in the validated in vitro biofilm model used.}, } @article {pmid34866130, year = {2022}, author = {Kim, GS and Park, CR and Kim, JE and Kim, HK and Kim, BS}, title = {Anti-Biofilm Effects of Torilis japonica Ethanol Extracts against Staphylococcus aureus.}, journal = {Journal of microbiology and biotechnology}, volume = {32}, number = {2}, pages = {220-227}, pmid = {34866130}, issn = {1738-8872}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Ethanol/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Sheep ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; }, abstract = {The spread of antibiotic-resistant strains of Staphylococcus aureus, a gram-positive opportunistic pathogen, has increased due to the frequent use of antibiotics. Inhibition of the quorum-sensing systems of biofilm-producing strains using plant extracts represents an efficient approach for controlling infections. Torilis japonica is a medicinal herb showing various bioactivities; however, no studies have reported the anti-biofilm effects of T. japonica extracts against drug-resistant S. aureus. In this study, we evaluated the inhibitory effects of T. japonica ethanol extract (TJE) on biofilm production in methicillin-sensitive S. aureus (MSSA) KCTC 1927, methicillin-resistant S. aureus (MRSA) KCCM 40510, and MRSA KCCM 40511. Biofilm assays showed that TJE could inhibit biofilm formation in all strains. Furthermore, the hemolysis of sheep blood was found to be reduced when the strains were treated with TJE. The mRNA expression of agrA, sarA, icaA, hla, and RNAIII was evaluated using reverse transcription-polymerase chain reaction to determine the effect of TJE on the regulation of genes encoding quorum sensing-related virulence factors in MSSA and MRSA. The expression of hla reduced in a concentration-dependent manner upon treatment with TJE. Moreover, the expression levels of other genes were significantly reduced compared to those in the control group. In conclusion, TJE can suppress biofilm formation and virulence factor-related gene expression in MSSA and MRSA strains. The extract may therefore be used to develop treatments for infections caused by antibiotic-resistant S. aureus.}, } @article {pmid34865925, year = {2022}, author = {Ma, T and Wang, Q and Wei, P and Zhu, K and Feng, A and He, Y and Wang, J and Shen, X and Cao, J and Li, C}, title = {EGCG-gelatin biofilm improved the protein degradation, flavor and micromolecule metabolites of tilapia fillets during chilled storage.}, journal = {Food chemistry}, volume = {375}, number = {}, pages = {131662}, doi = {10.1016/j.foodchem.2021.131662}, pmid = {34865925}, issn = {1873-7072}, mesh = {Animals ; Biofilms ; Catechin/analogs & derivatives ; *Gelatin ; Proteolysis ; Seafood/analysis ; *Tilapia ; }, abstract = {The protein degradation, flavor and micromolecule metabolites changes of (-)-epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on chilled tilapia fillets in 21 days were investigated. Morphology observations revealed EGT protected good connective myofibrillar protein. It maintained protein secondary structure by significantly increasing the proportion of α-helix (15.20%) and decreasing the ratio of random coils (22.02%) in the EGT group compared to the control (CON) group (P < 0.05). Metabolomics with UHPLC-Q-TOF/MS analysis indicated a distinct separation between the CON and treatment groups at the end of storage. Small peptides analysis demonstrated that the EGT group increased the level of sweet peptides. Additionally, the EGT group significantly reduced the formation of amino acid derivatives and esters and off-flavor development. Overall, EGT effectively improved flavor, inhibited fish protein oxidation/degradation, and verified metabolomics results. This study unveiled the potential of metabolomics to analyze metabolites determined by tilapia and monitor the changes during storage.}, } @article {pmid34865772, year = {2021}, author = {Wang, N and Jin, Y and He, G and Yuan, L}, title = {Development of multi-species biofilm formed by thermophilic bacteria on stainless steel immerged in skimmed milk.}, journal = {Food research international (Ottawa, Ont.)}, volume = {150}, number = {Pt A}, pages = {110754}, doi = {10.1016/j.foodres.2021.110754}, pmid = {34865772}, issn = {1873-7145}, mesh = {Animals ; Biofilms ; Geobacillus stearothermophilus ; *Milk ; *Stainless Steel ; }, abstract = {Thermophilic bacteria, such as Bacillus licheniformis, Geobacillus stearothermophilus, Bacillus Subtilis and Anoxybacillus flavithermus, are detected frequently in milk powder products. Biofilms of those strains act as a major contamination to milk powder manufactures and pose potential risks in food safety. In this study, we explored the developing process of multi-species biofilm formed by the four thermophilic bacteria on stainless steel immerged in skimmed milk. The results showed that the thermophilic strains possessed strong capacities to decompose proteins and lactose in skimmed milk, and the spoilage effects were superimposed from multiple strains. B. licheniformis was the most predominant species in the mixed-species biofilm after 12-h incubation. From 24 h to 48 h, G. stearothermophilus occupied the highest proportion. Within the multi-species biofilm, competitive relation existed between B. licheniformis and G. stearothermophilus, while synergistic impacts were observed between B. licheniformis and A. flavithermus. The interspecies mutual influences on biofilm development provided important evidences for understanding colonization of the predominant thermophilic bacteria during milk powder processing.}, } @article {pmid34865199, year = {2021}, author = {Park, T and Im, J and Kim, AR and Lee, D and Jeong, S and Yun, CH and Han, SH}, title = {Short-chain fatty acids inhibit the biofilm formation of Streptococcus gordonii through negative regulation of competence-stimulating peptide signaling pathway.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {59}, number = {12}, pages = {1142-1149}, pmid = {34865199}, issn = {1976-3794}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/drug effects/*growth & development ; DNA-Binding Proteins/*metabolism ; Fatty Acids, Volatile/*pharmacology ; Peptides/metabolism ; Quorum Sensing ; *Signal Transduction ; Streptococcus gordonii/drug effects/genetics/*physiology ; }, abstract = {Streptococcus gordonii, a Gram-positive commensal bacterium, is an opportunistic pathogen closely related to initiation and progression of various oral diseases, such as periodontitis and dental caries. Its biofilm formation is linked with the development of such diseases by enhanced resistance against antimicrobial treatment or host immunity. In the present study, we investigated the effect of short-chain fatty acids (SCFAs) on the biofilm formation of S. gordonii. SCFAs, including sodium acetate (NaA), sodium propionate (NaP), and sodium butyrate (NaB), showed an effective inhibitory activity on the biofilm formation of S. gordonii without reduction in bacterial growth. SCFAs suppressed S. gordonii biofilm formation at early time points whereas SCFAs did not affect its preformed biofilm. A quorum-sensing system mediated by competence-stimulating peptide (CSP) is known to regulate biofilm formation of streptococci. Interestingly, SCFAs substantially decreased mRNA expression of comD and comE, which are CSP-sensor and its response regulator responsible for CSP pathway, respectively. Although S. gordonii biofilm formation was enhanced by exogenous synthetic CSP treatment, such effect was not observed in the presence of SCFAs. Collectively, these results suggest that SCFAs have an anti-biofilm activity on S. gordonii through inhibiting comD and comE expression which results in negative regulation of CSP quorum-sensing system. SCFAs could be an effective anti-biofilm agent against S. gordonii for the prevention of oral diseases.}, } @article {pmid34864413, year = {2022}, author = {Santos, JCD and Lopes, DRG and Silva, LCF and Ramos, JLL and Dias, RS and Lima, HS and Sousa, MP and Waldow, VA and Paula, SO and Ferreira, SO and Silva, CCD}, title = {Characterization of the biofilm structure and microbial diversity of sulfate-reducing bacteria from petroleum produced water supplemented by different carbon sources.}, journal = {Journal of environmental management}, volume = {304}, number = {}, pages = {114189}, doi = {10.1016/j.jenvman.2021.114189}, pmid = {34864413}, issn = {1095-8630}, mesh = {Bacteria ; Biofilms ; Carbon ; Corrosion ; Dietary Supplements ; *Petroleum ; Sulfates ; Water ; }, abstract = {Colonization by sulfate-reducing bacteria (SRB) in environments associated with oil is mainly dependent on the availability of sulfate and carbon sources. The formation of biofilms by SRB increases the corrosion of pipelines and oil storage tanks, representing great occupational and operational risks and respective economic losses for the oil industry. The aim of this study was to evaluate the influence of the addition of acetate, butyrate, lactate, propionate and oil on the structure of biofilm formed in carbon steel coupons, as well as on the diversity of total bacteria and SRB in the planktonic and sessile communities from petroleum produced water. The biofilm morphology, chemical composition, average roughness and the microbial diversity was analyzed. In all carbon sources, formation of dense biofilm without morphological and/or microbial density differences was detected, with the most of cells observed in the form of individual rods. The diversity and richness indices of bacterial species in the planktonic community was greater than in the biofilm. Geotoga was the most abundant genus, and more than 85% of SRB species were common to all treatments. The functional predicted profile shown that the observed genres in planktonic communities were related to the reduction of sulfate, sulfite, elementary sulfur and other sulfur compounds, but the abundance varied between treatments. For the biofilm, the functions predicted profile for the oil treatment was the one that most varied in relation to the control, while for the planktonic community, the addition of all carbon sources interfered in the predicted functional profile. Thus, although it does not cause changes in the structure and morphology biofilm, the supplementation of produced water with different carbon sources is associated with changes in the SRB taxonomic composition and functional profiles of the biofilm and the planktonic bacterial communities.}, } @article {pmid34864174, year = {2022}, author = {Mahto, KU and Das, S}, title = {Bacterial biofilm and extracellular polymeric substances in the moving bed biofilm reactor for wastewater treatment: A review.}, journal = {Bioresource technology}, volume = {345}, number = {}, pages = {126476}, doi = {10.1016/j.biortech.2021.126476}, pmid = {34864174}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; *Bioreactors ; Denitrification ; Extracellular Polymeric Substance Matrix/chemistry ; Nitrification ; Nitrogen/analysis ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Among the several biofilm-based bioreactors, moving bed biofilm reactors (MBBR) have been extensively used for wastewater treatment due to low operational costs, technical feasibility, and stability. Biofilm forming strains, e.g., Stenotrophomonas maltophila DQ01, achieved 94.21% simultaneous nitrification and denitrification (SND) and 94.43% removal of total nitrogen (TN) at a cycle time of 7 h, and a biofilm consortium consisting of Chryseobacteriumsp. andRhodobactersp. achieved 86.8% removal of total organic carbon (TOC) at hydraulic retention time (HRT) of 24 h using lab-scale MBBR. Modifications in the surface properties of the biocarrier materials achieved 99.5 ± 1.1% chemical oxygen demand (COD) and 93.6 ± 2.3% NH4[+]-N removal, significantly higher than the conventional commercial carrier. This review article summarizes the application of MBBR technology for wastewater treatment. The importance of bacterial biofilm and extracellular polymeric substances (EPS), anammox-n-DAMO coupled processes, and carrier surface modifications in MBBR technology have also been discussed.}, } @article {pmid34863559, year = {2022}, author = {Wang, G and Hambly, AC and Dou, Y and Wang, G and Tang, K and Andersen, HR}, title = {Polishing micropollutants in municipal wastewater, using biogenic manganese oxides in a moving bed biofilm reactor (BioMn-MBBR).}, journal = {Journal of hazardous materials}, volume = {427}, number = {}, pages = {127889}, doi = {10.1016/j.jhazmat.2021.127889}, pmid = {34863559}, issn = {1873-3336}, mesh = {*Biofilms ; Bioreactors ; Manganese ; Oxides ; Poland ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Conventional wastewater treatment plants (WWTPs) cannot remove organic micropollutants efficiently, and thus various polishing processes are increasingly being studied. One such potential process is utilising biogenic manganese oxides (BioMnOx). The present study operated two moving bed biofilm reactors (MBBRs) with synthetic sewage as feed, one reactor feed was spiked with Mn(II) which allowed the continuous formation of BioMnOx by Mn-oxidising bacteria in the suspended biofilms (i.e. BioMn-MBBR). Spiking experiments with 14 micropollutants were conducted to investigate if BioMnOx combined with MBBR could be utilised to polish micropollutants in wastewater treatment. Results show enhanced removal by BioMn-MBBR over control MBBR (without BioMnOx) for specific micropollutants, such as diclofenac (36% vs. 5%) and sulfamethoxazole (80% vs. 24%). However, diclofenac removal was significantly inhibited when municipal wastewater was fed, and a further batch experiment demonstrates the reduced removal of diclofenac could be due to (unusual) higher pH in municipal wastewater compared to synthetic sewage. A shift in bacterial community was also observe in BioMn-MBBR over long-term operation. Overall, BioMn-MBBR in this study shows great potential for practical application in removing a larger range of micropollutants, which could be applied as an efficient polishing step for typical municipal wastewater.}, } @article {pmid34863036, year = {2022}, author = {Rivera, SF and Rimet, F and Vasselon, V and Vautier, M and Domaizon, I and Bouchez, A}, title = {Fish eDNA metabarcoding from aquatic biofilm samples: Methodological aspects.}, journal = {Molecular ecology resources}, volume = {22}, number = {4}, pages = {1440-1453}, doi = {10.1111/1755-0998.13568}, pmid = {34863036}, issn = {1755-0998}, mesh = {Animals ; Biodiversity ; Biofilms ; *DNA Barcoding, Taxonomic/methods ; *Ecosystem ; Environmental Monitoring/methods ; Fishes/genetics ; Lakes ; }, abstract = {Fish eDNA metabarcoding is usually performed from filtered water samples. The volume of filtered water depends on the study scope and can rapidly become time consuming according to the number of samples that have to be processed. To avoid time allocated to filtration, passive DNA samplers have been used to recover fish eDNA from marine environments faster. In freshwater ecosystems, aquatic biofilms were used to catch eDNA from macroinvertebrates. Here, we test the capacity of aquatic biofilms to entrap fish eDNA in a large lake and, therefore, the possibility to perform fish eDNA metabarcoding from this matrix compared to the traditional fish eDNA approach from filtered water samples. Methodological aspects of the use of aquatic biofilms for fish eDNA metabarcoding (e.g. PCR replicates, biological replicates, bioinformatics pipeline, reference database and taxonomic assignment) were validated against a mock community. When using biofilms from habitats sheltered from wind and waves, biofilm and water approach provided similar inventories. Richness and diversity were comparable between both approaches. Approaches differed only for rare taxa. Our results illustrate the capacity of aquatic biofilms to act as passive eDNA samplers of fish eDNA and, therefore, the possibility to use biofilms to monitor fish communities efficiently from biofilms. Furthermore, our results open up avenues of research to study a diversity of biological groups (among which bioindicators as diatoms, macroinvertebrates and fish) from eDNA isolated from a single environmental matrix reducing sampling efforts, analysis time and costs.}, } @article {pmid34863013, year = {2022}, author = {Sadanandan, B and Vaniyamparambath, V and Lokesh, KN and Shetty, K and Joglekar, AP and Ashrit, P and Hemanth, B}, title = {Candida albicans biofilm formation and growth optimization for functional studies using response surface methodology.}, journal = {Journal of applied microbiology}, volume = {132}, number = {4}, pages = {3277-3292}, doi = {10.1111/jam.15402}, pmid = {34863013}, issn = {1365-2672}, support = {SR/FT/LS-124/2012//Department of Science and Technology, Government of India/ ; }, mesh = {*Biofilms ; *Candida albicans ; Culture Media ; Polystyrenes ; }, abstract = {AIM: Optimization of Candida albicans growth and biofilm formation is essential for understanding the recalcitrance of this pathogen to advance functional analysis on hospital tools and material surfaces. Optimization and quantification of biofilm have always been a challenge using the conventional one variable at a time (OVAT) method. The present study uses central composite design-based response surface methodology for optimization of conditions to induce growth and biofilm formation in Candida albicans on polystyrene microtiter plates.

METHODS AND RESULTS: Statistical software package, Stat Soft®, STASTICA version 12.6 was used for data analysis. The variables considered in the design matrix were media pH, temperature, incubation period, shaker speed and inoculum size. A four-pronged quantification approach with XTT assay (cell viability), crystal violet assay (biofilm), calcofluor white assay and wet/dry weight measurements (cell mass) was used to understand different aspects of biofilm formation. Cell viability and cell mass were inversely related; however, biofilm was independent of these two factors. The study also highlighted the fact that foetal bovine serum does not significantly contribute to cell adhesion and in turn in vitro biofilm formation in some of the cultures.

CONCLUSIONS: A high-throughput optimization of C. albicans growth and biofilm formation on polystyrene microplate has been developed and validated.

This is a first time approach to optimize the interaction of parameters for C. albicans biofilm formation using RSM. Heterogeneity in growth conditions for local strains of C. albicans clinical isolates was observed. This microtiter plate-based method can be used for future screening of therapeutics for the control of C. albicans.}, } @article {pmid34862865, year = {2022}, author = {Catanoze, IA and de Souza, HS and Araújo, RC and Limírio, JPJDO and Duque, C and Dos Santos, PH and Pesqueira, AA and Guiotti, AM}, title = {Analysis of Biofilm Adhesion on CAD/CAM Lithium Disilicates Under Different Types of Intraoral Polishing.}, journal = {The European journal of prosthodontics and restorative dentistry}, volume = {30}, number = {2}, pages = {87-95}, doi = {10.1922/EJPRD_2275Catanoze09}, pmid = {34862865}, issn = {0965-7452}, mesh = {Biofilms ; Ceramics ; *Dental Polishing/methods ; Dental Porcelain ; *Lithium ; Materials Testing ; Streptococcus mutans ; Surface Properties ; }, abstract = {PURPOSE: To evaluate the adhesion of Streptococcus mutans (S. mutans) on lithium disilicate ceramics, submitted to different intraoral polishing protocols, and the degree of surface smoothness obtained.

MATERIALS AND METHODS: Fifty lithium disilicate specimens were divided into 5 groups (n=10): G1-Glaze Group (positive control); G2-Glaze Group + Wear + Glaze; G3-Wear Group (negative control); G4-Ceramisté Wear Group; G5-Optrafine Wear Group. Surface roughness (Ra - μm) was evaluated and the surface characteristics were assessed using a scanning electron microscope (SEM); to assess S. mutans biofilm, the number of cultured cells was evaluated by counting colony-forming units (CFU/mL). The data underwent one-way ANOVA followed by Tukey's test (P⟨.05).

RESULTS: There was a significant difference in the surface roughness of all groups compared with G3. There was no significant difference between the G4 and G5 groups that received polishing. G1 group had the lowest mean roughness values. There was a difference in Log values (CFU/mL) between the G3 group and the groups that received glaze (G1 and G2). The G3 group had the highest adhesion of S. mutans (4.53 Log).

CONCLUSION: The most effective polishing protocol after wear is glazing, presenting the lowest roughness and CFU/mL values.}, } @article {pmid34862746, year = {2022}, author = {Ali, IAA and Lévesque, CM and Neelakantan, P}, title = {Fsr quorum sensing system modulates the temporal development of Enterococcus faecalis biofilm matrix.}, journal = {Molecular oral microbiology}, volume = {37}, number = {1}, pages = {22-30}, doi = {10.1111/omi.12357}, pmid = {34862746}, issn = {2041-1014}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; *Enterococcus faecalis/genetics ; Extracellular Polymeric Substance Matrix/metabolism ; Gelatinases/genetics/metabolism ; Gene Expression Regulation, Bacterial ; *Quorum Sensing ; }, abstract = {Quorum sensing (QS) is a cell-to-cell communication process that regulates major pathogenic attributes in bacteria including biofilm formation, secretion of virulence factors, and antimicrobial resistance. The two-component Fsr-QS system of the nosocomial pathogen Enterococcus faecalis controls the production of extracellular gelatinase that contributes to biofilm development by enhancing the release of nucleic acids into the biofilm matrix. However, the contribution of this system to the deposition of other biofilm matrix components such as polysaccharides and proteins remains unknown. Using wild type and mutant strains, we discovered that biofilm formation was attenuated by inactivation of the Fsr system or its downstream gelatinase production. Inactivation of the Fsr system caused a modest, yet significant reduction in biofilm metabolic activity without affecting cell counts. Inactivation of the QS-signal sensor FsrC and response regulator FsrA resulted in decreased extracellular polysaccharides and proteins in biofilms in a temporal manner. Irrespective of biofilm age, eDNA levels were reduced in the gelatinase mutant strain. Our results collectively suggest that the Fsr system contributes to the temporal deposition of polysaccharides and proteins into the extracellular polymeric matrix (EPS) of E. faecalis biofilm, without affecting bacterial viability. This understanding of the role of the Fsr-QS system in biofilm development may reveal a novel target to develop effective antibiofilm agents to tackle E. faecalis-mediated infections such as in dental root canals, heart valves, and surgical sites.}, } @article {pmid34862649, year = {2022}, author = {Ronin, D and Boyer, J and Alban, N and Natoli, RM and Johnson, A and Kjellerup, BV}, title = {Current and novel diagnostics for orthopedic implant biofilm infections: a review.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {130}, number = {2}, pages = {59-81}, doi = {10.1111/apm.13197}, pmid = {34862649}, issn = {1600-0463}, mesh = {Animals ; Bacteria/classification/genetics ; Bacterial Physiological Phenomena ; *Biofilms ; Hip/surgery ; Humans ; Knee/surgery ; Orthopedics ; Prostheses and Implants/*adverse effects ; Prosthesis-Related Infections/*diagnosis/microbiology ; }, abstract = {Biofilm infections involving orthopedic implants are a global problem. They contribute to severe complications and mortality, as well as increased use of antibiotic treatments and development of antibiotic-resistant microorganisms. More than 1 million hip and knee arthroplasties are performed each year in the United States. These hard-to-treat infections lead to patient distress, increased morbidity, and high financial costs to both patients and healthcare systems. There is a need to improve the diagnosis of such biofilm infections to allow for earlier detection and treatment. Current diagnostics rely on clinical signs for infections such as loss of function, fever, rubor, patient history of the predisposing condition, persisting infection, failure of antibiotic treatment, and documentation of antibiotic failure. Below, we present a framework which outlines the data gaps in the conventional laboratory techniques used in clinical diagnostics; we also discuss promising novel diagnostic methods which are currently used solely in research. It is critical to assess these novel infection diagnostic techniques and address the data gaps and clinical hesitance preventing application in a clinical setting. Additionally, the combination of conventional and novel diagnostic technologies would streamline the diagnostic process of biofilm infections associated with orthopedic implants.}, } @article {pmid34862085, year = {2022}, author = {Mysore, AR and Aras, MA and Chitre, V}, title = {Letter to the Editor regarding "Effect of daily use of an enzymatic denture cleanser on Candida albicans biofilms formed on polyamide and poly(methyl methacrylate) resins: An in vitro study." J Prosthet Dent 2014;112:1349-55 and "Efficacy of denture cleansers on Candida spp. biofilm formed on polyamide and polymethyl methacrylate resins." J Prosthet Dent 2011;105:51-8.}, journal = {The Journal of prosthetic dentistry}, volume = {127}, number = {5}, pages = {819}, doi = {10.1016/j.prosdent.2021.11.004}, pmid = {34862085}, issn = {1097-6841}, mesh = {Biofilms ; Candida ; *Candida albicans ; Denture Bases ; *Denture Cleansers/pharmacology/therapeutic use ; Nylons ; Polymethyl Methacrylate ; Surface Properties ; }, } @article {pmid34860858, year = {2021}, author = {Ma, Q and Pan, Y and Chen, Y and Yu, S and Huang, J and Liu, Y and Gong, T and Zou, J and Li, Y}, title = {Acetylation of glucosyltransferases regulates Streptococcus mutans biofilm formation and virulence.}, journal = {PLoS pathogens}, volume = {17}, number = {12}, pages = {e1010134}, pmid = {34860858}, issn = {1553-7374}, mesh = {Acetylation ; Acetyltransferases/*metabolism ; Animals ; *Biofilms ; Female ; Glucosyltransferases/*metabolism ; Lysine/metabolism ; Rats ; Rats, Sprague-Dawley ; Streptococcus mutans/*pathogenicity/physiology ; Virulence/*physiology ; }, abstract = {Lysine acetylation is a frequently occurring post-translational modification (PTM), emerging as an important metabolic regulatory mechanism in prokaryotes. This process is achieved enzymatically by the protein acetyltransferase (KAT) to specifically transfer the acetyl group, or non-enzymatically by direct intermediates (acetyl phosphate or acetyl-CoA). Although lysine acetylation modification of glucosyltransferases (Gtfs), the important virulence factor in Streptococcus mutans, was reported in our previous study, the KAT has not been identified. Here, we believe that the KAT ActG can acetylate Gtfs in the enzymatic mechanism. By overexpressing 15 KATs in S. mutans, the synthesized water-insoluble extracellular polysaccharides (EPS) and biofilm biomass were measured, and KAT (actG) was identified. The in-frame deletion mutant of actG was constructed to validate the function of actG. The results showed that actG could negatively regulate the water-insoluble EPS synthesis and biofilm formation. We used mass spectrometry (MS) to identify GtfB and GtfC as the possible substrates of ActG. This was also demonstrated by in vitro acetylation assays, indicating that ActG could increase the acetylation levels of GtfB and GtfC enzymatically and decrease their activities. We further found that the expression level of actG in part explained the virulence differences in clinically isolated strains. Moreover, overexpression of actG in S. mutans attenuated its cariogenicity in the rat caries model. Taken together, our study demonstrated that the KAT ActG could induce the acetylation of GtfB and GtfC enzymatically in S. mutans, providing insights into the function of lysine acetylation in bacterial virulence and pathogenicity.}, } @article {pmid34860440, year = {2022}, author = {Mohamed, AM and Cifuente, DA and Satorres, SE and Mattana, CM}, title = {Biological activity of roots and aerial parts of Zinnia peruviana on pathogenic micro-organisms in planktonic state and biofilm forming.}, journal = {Letters in applied microbiology}, volume = {74}, number = {3}, pages = {419-428}, doi = {10.1111/lam.13622}, pmid = {34860440}, issn = {1472-765X}, support = {PROICO 02-0218//Universidad Nacional de San Luis/ ; 02-2516//Universidad Nacional de San Luis/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; *Plankton ; *Plant Extracts/pharmacology ; Plant Leaves ; }, abstract = {Microbial resistance to antibiotics affects the control of clinical infections and is a growing concern in global public health. One important mechanism whereby micro-organisms acquire resistance is biofilm formation. This context has led to the investigation of new antimicrobial substances from plants popularly used in folk medicine. In this work, we studied the antimicrobial and antibiofilm activity of Zinnia peruviana roots, ziniolide (major root metabolite) and aerial parts against Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The minimum inhibitory and minimum microbicidal concentration and inhibition of biofilm production was determined. All Z. peruviana extracts showed antimicrobial activity, but that corresponding to the roots was the most active one. The best inhibitory and microbicidal activity was detected against Gram-positive bacteria (0·039-0·078 mg ml[-1]). The acetonic extract from Z. peruviana leaves showed moderate activity against Gram-positive bacteria (0·625 mg ml[-1]). Acetonic extract of Z. peruviana flowers showed weak activity (1·25-5 mg ml[-1]). All the extracts tested showed inhibition of biofilm formation, as well as the ziniolide, however, roots and flowers extracts showed higher antibiofilm activity particularly against Staphylococcus, Listeria and Candida. The extracts tested may be a promising natural alternative for the control of microbial infections.}, } @article {pmid34860214, year = {2022}, author = {Yi, SY and Lin, HY and Yang, LC and Tseng, SC and Sun, AY and Chen, C and Wan, D}, title = {Substrate-independent adsorption of nanoparticles as anti-biofilm coatings.}, journal = {Biomaterials science}, volume = {10}, number = {2}, pages = {410-422}, doi = {10.1039/d1bm01580j}, pmid = {34860214}, issn = {2047-4849}, mesh = {Adsorption ; Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Metal Nanoparticles ; Mice ; NIH 3T3 Cells ; Staphylococcus aureus ; }, abstract = {Healthcare-associated infections are common causes of morbidity and mortality. Advanced nanotechnology provides a means of overcoming this problem, but it remains challenging to develop universal coating strategies for decorating antimicrobial nanomaterials onto various clinical devices. In this paper, we propose a general silane-based method for immobilizing monolayer metal nanoparticle (NP) arrays onto any type of substrate surface-especially for a diverse range of clinical implantable devices. The surface silanization was achieved simply through the adsorption of N[1]-(3-trimethoxysilylpropyl)diethylenetriamine (TMS), regardless of the material (polymer, metal, oxide) or morphology (flat, curved, textured) of the substrate, with no need for pretreatment or expensive instrumentation. Monolayers of various nanostructures (Ag, Au, and hollow Au NPs) were then decorated rapidly onto the TMS-treated substrates, thereby further functionalizing their surfaces. In particular, immobilization of the Ag NPs resulted in excellent anti-biofilm efficacy against three clinically life-threatening pathogens: Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. Sustained release of Ag[+] ions led to durable inhibition of bacterial attachment for up to 28 days. Studies with NIH3T3 fibroblasts revealed that the Ag NP arrays displayed no cytotoxicity toward mammalian cells. Overall, this universal coating process appears to be an innovative method for the surface-functionalization of diverse materials and devices employed in the fields of energy, sensing, and medicine-especially to prevent healthcare-associated infections arising from the use of clinical implantable devices in hospitals.}, } @article {pmid34859164, year = {2021}, author = {Staats, A and Li, D and Sullivan, AC and Stoodley, P}, title = {Biofilm formation in periprosthetic joint infections.}, journal = {Annals of joint}, volume = {6}, number = {}, pages = {}, pmid = {34859164}, issn = {2415-6809}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; }, abstract = {Formation of microbial biofilms has long been implicated in the occurrence of periprosthetic joint infections (PJIs). Despite the widespread acknowledgment of the severity of these infections, much is still unknown regarding the underlying mechanisms of biofilm establishment and proliferation in the joint space. The presence of these resilient, complex communities poses many clinical challenges with respect to prevention, diagnosis, and treatment practices. Mature biofilms are known to be highly recalcitrant to antibiotic therapeutics as well as host immune system mediated clearance. A comprehensive understanding of biofilms in the unique joint environment at the molecular level will provide clinicians valuable insight into how best to combat them. As each stage in the process of biofilm establishment has the potential for clinical intervention, this review will provide a sequential analysis of the existing literature, following each step in the formation cycle. New insights into bacterial survival mechanisms from antimicrobial challenge and host immune defenses will be discussed. These new observations in the field may shed light on the early protection conferred upon entry into the joint space ultimately leading to the establishment of a mature biofilm. Additionally, standards of clinical diagnosis as well as current measures of prevention and treatment will be briefly discussed.}, } @article {pmid34857315, year = {2021}, author = {Sonnleitner, D and Sommer, C and Scheibel, T and Lang, G}, title = {Approaches to inhibit biofilm formation applying natural and artificial silk-based materials.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {131}, number = {}, pages = {112458}, doi = {10.1016/j.msec.2021.112458}, pmid = {34857315}, issn = {1873-0191}, mesh = {Animals ; Anti-Bacterial Agents ; *Anti-Infective Agents/pharmacology ; Biocompatible Materials/pharmacology ; Biofilms ; Silk ; *Spiders ; }, abstract = {The discovery of penicillin started a new era of health care since it allowed the effective treatment of formerly deadly infections. As a drawback, its overuse led to a growing number of multi-drug resistant pathogens. Challenging this arising threat, material research focuses on the development of microbe-killing or microbe repellent agents implementing such functions directly into materials. Due to their biocompatibility, non-immunogenicity and mechanical strength, silk-based materials are attractive candidates for applications in the biomedical field. Furthermore, it has been observed that silks display high persistency in their natural environment giving reason to suspect that they might be attractive candidates to prevent microbial infestation. The current review describes the process of biofilm formation on medical devices and the most common strategies to prevent it, divided into effects of surface topography, material modification and integrated additives. In this context, recent state of the art developments in the field of natural and artificial silk-based materials with microbe-repellant or antimicrobial properties are addressed. These silk properties are controversially discussed and conclusions are drawn as to which parameters will be decisive for the successful design of new bio-functional materials based on the blueprint of silk proteins.}, } @article {pmid34857279, year = {2021}, author = {Yang, Z and Ren, X and Liu, Y}, title = {Multifunctional 3D printed porous GelMA/xanthan gum based dressing with biofilm control and wound healing activity.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {131}, number = {}, pages = {112493}, doi = {10.1016/j.msec.2021.112493}, pmid = {34857279}, issn = {1873-0191}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Bandages ; Biofilms ; Mice ; Polysaccharides, Bacterial ; Porosity ; Printing, Three-Dimensional ; *Wound Healing ; }, abstract = {Bacterial infections are the major challenges of wound treatment in current clinical applications. In this study, Three-dimensional (3D) antibacterial wound dressing has been fabricated via introducing N-halamine/TiO2 to gelatin methacrylate and xanthan gum. The prepared 3D printed dressings showed ideal swelling ratio and excellent water uptake efficiency. TiO2 nanoparticles were introduced by in-situ to improve the ultraviolet stability of N-halamines. The 3D printed GX2-TiO2-PSPH-Cl prepared dressings containing titanium dioxide retained 0.19% active chlorine after ultraviolet irradiation for 20 min, which was much higher than that of N-halamine dressings without the addition of TiO2. The 3D printed dressings showed good antibacterial activity, and 100% of Escherichia coli O157:H7 and Staphylococcus aureus were inactivated after 60 min of contact. Furthermore, the biofilm test indicated that the 3D antibacterial dressings were able to inhibit the formation of bacterial biofilm. The 3D printed dressings possess outstanding biocompatibility. Moreover, in vivo data demonstrated that the 3D printed dressings could significantly accelerate wound healing in a mouse model, indicating that the developed 3D printed dressings are ideal candidates for wound treatment.}, } @article {pmid34856247, year = {2022}, author = {Gu, M and Fang, W and Li, X and Yang, W and Waigi, MG and Kengara, FO and Wu, S and Han, C and Zhang, Y}, title = {Up-regulation of ribosomal and carbon metabolism proteins enhanced pyrene biodegradation in fulvic acid-induced biofilm system.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {294}, number = {}, pages = {118602}, doi = {10.1016/j.envpol.2021.118602}, pmid = {34856247}, issn = {1873-6424}, mesh = {Benzopyrans ; Biodegradation, Environmental ; Biofilms ; *Carbon ; *Polycyclic Aromatic Hydrocarbons ; Pyrenes ; Up-Regulation ; }, abstract = {The polycyclic aromatic hydrocarbons (PAHs) that enter the aqueous phase usually coexist with fulvic acid (FA). Therefore, we initiated this investigation to explore the influences of FA on bacterial biofilm formation and its potential to biodegrade pyrene (PYR), using electron microscopic techniques and isobaric tags for relative and absolute quantification (iTRAQ). Our results revealed that FA stimulated biofilm formation and enhanced the biodegradation of PYR. First, FA favored the three-dimensional proliferation of bacteria, with an OD590/OD600 value of up to 14.78, and the extracellular surfaces covered by a layer of biomaterials. Distinctive intracellular morphologies of texture and organization were accompanied by reduced inter-bacterial distances of less than 0.31 μm. The biofilms formed displayed interactions between FA and surficial proteins, as noted by band shifts for the C-O and CO groups. Strikingly, FA triggered the upregulation of 130 proteins that were either operational in biofilm formation or in metabolic adjustments; with the changes supported by the increasing intensity of free amino acids and the newly generated N-O bonds. The results above revealed that the enhanced biodegradation was related to the up-regulation of the proteins functioned for ribosomal and carbon metabolism, and the ultra-structural changes in FA-induced biofilm system.}, } @article {pmid34856045, year = {2022}, author = {Shariati, A and Vesal, S and Khoshbayan, A and Goudarzi, P and Darban-Sarokhalil, D and Razavi, S and Didehdar, M and Chegini, Z}, title = {Novel strategies for inhibition of bacterial biofilm in chronic rhinosinusitis.}, journal = {Journal of applied microbiology}, volume = {132}, number = {4}, pages = {2531-2546}, doi = {10.1111/jam.15398}, pmid = {34856045}, issn = {1365-2672}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria/genetics ; Biofilms ; Chronic Disease ; Humans ; *Rhinitis/drug therapy/microbiology ; *Sinusitis/drug therapy/microbiology ; }, abstract = {An important role has been recently reported for bacterial biofilm in the pathophysiology of chronic diseases, such as chronic rhinosinusitis (CRS). CRS, affecting sinonasal mucosa, is a persistent inflammatory condition with a high prevalence around the world. Although the exact pathological mechanism of this disease has not been elicited yet, biofilm formation is known to lead to a more significant symptom burden and major objective clinical indicators. The high prevalence of multidrug-resistant bacteria has severely restricted the application of antibiotics in recent years. Furthermore, systemic antibiotic therapy, on top of its insufficient concentration to eradicate bacteria in the sinonasal biofilm, often causes toxicity, antibiotic resistance, and an effect on the natural microbiota, in patients. Thus, coming up with alternative therapeutic options instead of systemic antibiotic therapy is emphasized in the treatment of bacterial biofilm in CRS patients. The use of topical antibiotic therapy and antibiotic eluting sinus stents that induce higher antibiotic concentration, and decrease side effects could be helpful. Besides, recent research recognized that various natural products, nitric oxide, and bacteriophage therapy, in addition to the hindered biofilm formation, could degrade the established bacterial biofilm. However, despite these improvements, new antibacterial agents and CRS biofilm interactions are complicated and need extensive research. Finally, most studies were performed in vitro, and more preclinical animal models and human studies are required to confirm the collected data. The present review is specifically discussing potential therapeutic strategies for the treatment of bacterial biofilm in CRS patients.}, } @article {pmid34855103, year = {2022}, author = {Jarros, IC and Barros, ILE and Prado, A and Corrêa, JL and Malacrida, AM and Negri, M and Svidzinski, TIE}, title = {Rhodotorula sp. and Trichosporon sp. are more Virulent After a Mixed Biofilm.}, journal = {Mycopathologia}, volume = {187}, number = {1}, pages = {85-93}, pmid = {34855103}, issn = {1573-0832}, support = {001//coordenação de aperfeiçoamento de pessoal de nível superior/ ; }, mesh = {Antifungal Agents ; Biofilms ; *Coinfection ; Humans ; *Rhodotorula ; *Trichosporon ; }, abstract = {Rhodotorula spp. and Trichosporon spp. are opportunistic pathogens, and although an association between these two species in the same infection appears to be uncommon, it has been reported. This is the first study that aimed to evaluate the pathogenesis of a co-infection by R. mucilaginosa and T. asahii, using a new in vivo model, the Zophobas morio larvae. Suspensions from planktonic and biofilm-recovered cells were injected in the larvae as in monospecies as mixed (a ratio of 1:1 for both agents of a of 10[5] inoculum). Individual and mixed biofilms of R. mucilaginosa and T. asahii were produced for 24 and 48 h, and they were partially characterized by crystal violet and reduction of tetrazolium salt. When evaluating the impact of the planktonic suspension in vivo we verified that the fungi in monoculture were more able to kill the larvae than those from planktonic mixed suspension. On the other hand, regarding biofilm-recovered cells, there was an increase in the death of larvae infected for mixed suspensions. Moreover, the death rate was more pronounced when the larvae were infected with 48 h biofilm-recovered cells than the 24 h ones. T. asahii was the best producer of total biomass, mainly in 48 h. The metabolic activity for both yeasts organized in biofilm maintained the same pattern between 24 and 48 h. The present study proves a synergistic interaction between R. mucilaginosa and T. asahii after an experience in a mixed biofilm. Our results suggest that both species were benefited from this interaction, acquiring a greater potential for virulence after passing through the biofilm and this ability was acquired by the cells released from the biofilm.}, } @article {pmid34853964, year = {2021}, author = {Babushkina, IV and Mamonova, IА and Ulyanov, VY and Gladkova, ЕV and Shpinyak, SP}, title = {Resistance to Antibiotics in Plankton and Biofilm Cultures of Pseudomonas aeruginosa Clinical Strains.}, journal = {Bulletin of experimental biology and medicine}, volume = {172}, number = {2}, pages = {155-157}, pmid = {34853964}, issn = {1573-8221}, mesh = {Anti-Bacterial Agents/*pharmacology ; Arthroplasty, Replacement/adverse effects ; Biofilms/*drug effects/growth & development ; *Drug Resistance, Microbial ; Humans ; Microbial Sensitivity Tests ; Plankton/*drug effects/physiology ; Postoperative Complications/microbiology ; Prosthesis-Related Infections/microbiology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {Biofilms formed by Pseudomonas aeruginosa strains isolated from biomaterial of patients with implant-associated infection are characterized by much higher resistance to antibiotics of various classes than plankton cultures of these strains. The concentrations of antibiotics causing the death of 90% of P. aeruginosa biofilm (MIC90) was 2-6 μg/ml for fluoroquinolones, 267-356 μg/ml for cephalosporins, and 92-215 μg/ml for amikacin, which significantly (p<0.05) differed from MIC90 for plankton cultures that did not exceed 0.8 μg/ml for fluoroquinolones, 19 μg/ml for cephalosporins, and 3 μg/ml for amikacin. The degree of the microbial biofilm maturity also affected antibiotic resistance.}, } @article {pmid34853316, year = {2021}, author = {Remple, KL and Silbiger, NJ and Quinlan, ZA and Fox, MD and Kelly, LW and Donahue, MJ and Nelson, CE}, title = {Coral reef biofilm bacterial diversity and successional trajectories are structured by reef benthic organisms and shift under chronic nutrient enrichment.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {84}, pmid = {34853316}, issn = {2055-5008}, support = {NA18OAR4170076//NOAAA/ ; }, mesh = {Animals ; *Anthozoa ; Bacteria/genetics ; Biofilms ; *Coral Reefs ; Nutrients ; }, abstract = {Work on marine biofilms has primarily focused on host-associated habitats for their roles in larval recruitment and disease dynamics; little is known about the factors regulating the composition of reef environmental biofilms. To contrast the roles of succession, benthic communities and nutrients in structuring marine biofilms, we surveyed bacteria communities in biofilms through a six-week succession in aquaria containing macroalgae, coral, or reef sand factorially crossed with three levels of continuous nutrient enrichment. Our findings demonstrate how biofilm successional trajectories diverge from temporal dynamics of the bacterioplankton and how biofilms are structured by the surrounding benthic organisms and nutrient enrichment. We identify a suite of biofilm-associated bacteria linked with the orthogonal influences of corals, algae and nutrients and distinct from the overlying water. Our results provide a comprehensive characterization of marine biofilm successional dynamics and contextualize the impact of widespread changes in reef community composition and nutrient pollution on biofilm community structure.}, } @article {pmid34852445, year = {2021}, author = {Jiang, L and Zhang, Y and Shen, Q and Mao, Y and Zhang, Q and Ji, F}, title = {The metabolic patterns of the complete nitrates removal in the biofilm denitrification systems supported by polymer and water-soluble carbon sources as the electron donors.}, journal = {Bioresource technology}, volume = {342}, number = {}, pages = {126002}, doi = {10.1016/j.biortech.2021.126002}, pmid = {34852445}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; Electrons ; *Nitrates ; Polymers ; Water ; }, abstract = {In this study, two denitrification bio-filters adopted polycaprolactone (PCL) and sodium acetate (NaAc) as polymer and water-soluble carbon sources respectively. With the increasing influent nitrate concentrations, NaAc bio-filter always had shorter HRT to achieve complete nitrate removal. Furthermore, the optimal volumetric denitrification rate in NaAc bio-filter was 0.728 g N/(L·d), which was higher than 0.561 g N/(L·d) in PCL bio-filter. For nitrates removal, the costs of bio-filters supported by NaAc and PCL were 24.93 and 120.25 CNY/kg N respectively. Although Proteobacteria in PCL bio-filter was abundant with 83.98%, NaAc bio-filter had better denitrification performance, due to the appropriate ratio of nitrate removal microorganisms and organic matters degradation organisms. The total abundance value of the denitrification genera is NaAc (16.06%) < PCL (41.19%). However, PCL bio-filter had poor denitrification performance, due to the lower adequacy of PCL depolymerization enzymes and the low expression of the key genes for denitrification.}, } @article {pmid34851721, year = {2022}, author = {Mukhi, M and Vishwanathan, AS}, title = {Beneficial Biofilms: a Minireview of Strategies To Enhance Biofilm Formation for Biotechnological Applications.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {3}, pages = {e0199421}, pmid = {34851721}, issn = {1098-5336}, mesh = {Animals ; Bacteria/genetics ; *Biofilms ; *Ecosystem ; Extracellular Polymeric Substance Matrix ; Quorum Sensing/genetics ; Wastewater ; }, abstract = {The capacity of bacteria to form biofilms is an important trait for their survival and persistence. Biofilms occur naturally in soil and aquatic environments, are associated with animals ranging from insects to humans, and are also found in built environments. They are typically encountered as a challenge in health care, food industry, and water supply ecosystems. In contrast, they are known to play a key role in the industrial production of commercially valuable products, environmental remediation processes, and microbe-catalyzed electrochemical systems for energy and resource recovery from wastewater. While there are many recent articles on biofilm control and removal, review articles on promoting biofilm growth for biotechnological applications are unavailable. Biofilm formation is a tightly regulated response to perturbations in the external environment. The multistage process, mediated by an assortment of proteins and signaling systems, involves the attachment of bacterial cells to a surface followed by their aggregation in a matrix of extracellular polymeric substances. Biofilms can be promoted by altering the external environment in a controlled manner, supplying molecules that trigger the aggregation of cells and engineering genes associated with biofilm development. This minireview synthesizes findings from studies that have described such strategies and highlights areas needing research attention.}, } @article {pmid34850749, year = {2021}, author = {Usman, Y and Bakari, AG and Abdullahi, IN and Ahmad, AE and Sani-Bello, F and Sagay, AS and Olayinka, AT}, title = {Phenotypic profile and antibiogram of biofilm-producing bacteria isolates from diabetic foot ulcers in Zaria, Nigeria.}, journal = {The Nigerian postgraduate medical journal}, volume = {28}, number = {4}, pages = {233-239}, doi = {10.4103/npmj.npmj_552_21}, pmid = {34850749}, issn = {1117-1936}, support = {D43 TW010130/TW/FIC NIH HHS/United States ; }, mesh = {Adult ; Aged ; Anti-Bacterial Agents/therapeutic use ; Bacteria ; Biofilms ; Cross-Sectional Studies ; *Diabetes Mellitus ; *Diabetic Foot/drug therapy/epidemiology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Nigeria ; Quality of Life ; }, abstract = {BACKGROUND: Diabetic foot ulcers (DFUs) present with high morbidity and reduce patient's quality of life. There is a gross paucity of data on biofilm-producing bacteria in DFU Infection in North-Western Nigeria. The study sought to determine the biofilm-forming ability of bacteria isolates from DFUs and determine their antimicrobial susceptibility pattern in Zaria, North-Western Nigeria.

MATERIALS AND METHODS: This hospital-based cross-sectional study of patients with DFUs was conducted from June 2018 to February 2020. Consecutive biopsies were aseptically collected. Bacteria were isolated and identified using a Microgen kit. Biofilm forming ability and antibiogram of isolates were determined using microtitre plate and disk diffusion methods, respectively.

RESULTS: Of the 225 participants enrolled, males constituted the majority, 144 (64.0%) with 88 (36.0%) females, the median age of participants was 54 (48-60) years, and the age range was 36-77 years. A total of 172 bacteria were isolated, and 123 (71.5%) were biofilm producers. Staphylococcus aureus (26.7%) was the highest biofilm producer, while Citrobacter freundii and Stenotrophomonas maltophilia were the least biofilm producers, 1 (0.6%) each. A disproportionate resistance pattern was demonstrated among the biofilm and non-biofilm producers against the cephalosporins tested, ceftazidime (68% vs. 18%), ceftriaxone (50% vs. 8.0%) and cefotaxime (21% vs. 0.0%). About 46% and 68% of the biofilm producers were resistant to gentamycin and ciprofloxacin, respectively. While only 2% of the non-biofilm producers were resistant to imipenem, 11% of the biofilm producers were resistant to it.

CONCLUSION: These findings revealed a high proportion of biofilm-producing bacteria and were more resistant than non-biofilm producers.}, } @article {pmid34849798, year = {2022}, author = {Béchon, N and Ghigo, JM}, title = {Gut biofilms: Bacteroides as model symbionts to study biofilm formation by intestinal anaerobes.}, journal = {FEMS microbiology reviews}, volume = {46}, number = {2}, pages = {}, doi = {10.1093/femsre/fuab054}, pmid = {34849798}, issn = {1574-6976}, mesh = {Animals ; Anti-Bacterial Agents ; Bacteria ; *Bacteroides/physiology ; Biofilms ; *Gastrointestinal Microbiome/physiology ; Humans ; Mammals ; }, abstract = {Bacterial biofilms are communities of adhering bacteria that express distinct properties compared to their free-living counterparts, including increased antibiotic tolerance and original metabolic capabilities. Despite the potential impact of the biofilm lifestyle on the stability and function of the dense community of micro-organisms constituting the mammalian gut microbiota, the overwhelming majority of studies performed on biofilm formation by gut bacteria focused either on minor and often aerobic members of the community or on pathogenic bacteria. In this review, we discuss the reported evidence for biofilm-like structures formed by gut bacteria, the importance of considering the anaerobic nature of gut biofilms and we present the most recent advances on biofilm formation by Bacteroides, one of the most abundant genera of the human gut microbiota. Bacteroides species can be found attached to food particles and colonizing the mucus layer and we propose that Bacteroides symbionts are relevant models to probe the physiology of gut microbiota biofilms.}, } @article {pmid34848194, year = {2022}, author = {Marin, LM and Cury, JA and Siqueira, WL}, title = {Validation of a cariogenic biofilm model by evaluating the effect of fluoride on enamel demineralization.}, journal = {Journal of microbiological methods}, volume = {192}, number = {}, pages = {106386}, doi = {10.1016/j.mimet.2021.106386}, pmid = {34848194}, issn = {1872-8359}, support = {106657//CIHR/Canada ; 400347//CIHR/Canada ; }, mesh = {Animals ; Biofilms/*growth & development ; Cariostatic Agents/*pharmacology ; Cattle ; Dental Caries/microbiology/prevention & control ; Dental Enamel/drug effects/*metabolism ; Fluorides/*pharmacology ; Saliva/microbiology ; Streptococcus mutans/*growth & development ; Sucrose/pharmacology ; Tooth Demineralization/drug therapy/*microbiology/prevention & control ; }, abstract = {In vitro biofilm models have been extensively used, but only few of the models available to date had been validated in terms of the dose-response effect of anti-caries and/or antimicrobial substances. Additionally, none of the validated models allow the use of microliter volumes of the treatment solutions, needed mainly to test (screen) novel but expensive substances under development. This study aimed at modifying an in vitro cariogenic Streptococcus mutans biofilm model and validating it by assessing the dose-response effect of fluoride on enamel demineralization. S. mutans cariogenic biofilms were developed on saliva-coated enamel slabs previously bonded to acrylic holders fixed to a lid of a culture plate. Biofilms were incubated 8 h/day in culture medium supplemented with 1% sucrose and then overnight in culture medium with glucose 0.1 mM. Biofilms were also treated 2×/day with 2.0 mL of solutions containing 0, 125, 275 and 1250 μg F/mL (n = 10/group). The replaced culture medium was used to: determine the biofilm acidogenicity; estimate the demineralization of enamel; and monitor the fluoride concentration. At 144 h, biofilms were collected for fluoride concentration analyses, and the fluoride uptake by enamel was determined in each slab. The model showed a dose-response effect of fluoride (R[2] = 0.96, p < 0.001) between enamel demineralization and the fluoride concentration of the treatments. Water-soluble and bound biofilm fluoride concentrations (p < 0.007), as well as the firmly-bound fluoride concentration found in enamel (p < 0.0001), increased in a dose-dependent manner. Our model constitutes a validated approach that would allow the assessment of the anticaries potential of novel biotechnological strategies, as in the case of expensive salivary peptides, because it would allow to test the treatment solutions using smaller volumes.}, } @article {pmid34847498, year = {2022}, author = {Tran, VN and Park, S and Khan, F and Truong, VG and Jeong, S and Lee, DH and Kim, YM and Kang, HW}, title = {Collective bacterial disinfection by opto-chemical treatment on mature biofilm in clinical endoscope.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {226}, number = {}, pages = {112367}, doi = {10.1016/j.jphotobiol.2021.112367}, pmid = {34847498}, issn = {1873-2682}, mesh = {*Biofilms ; }, abstract = {The present study proposes an innovative opto-chemical treatment using a basket-integrated optical device (BIOD) to disinfect mature bacterial biofilm on endoscope channels. A BIOD was designed to position an optical diffuser on the central axis of an endoscope channel and to distribute laser light concentrically to the bacterial biofilm on the channel surface. To apply thermal damage and oxidative stress to the bacterial biofilm, a low concentration of a crosslinking agent (glutaraldehyde ~0.5%) was combined with 808 nm infrared (IR) and 405 nm blue (BL) laser lights. The applied irradiances of IR and BL were 10 W/cm[2] and 1.6 W/cm[2] for Teflon channel model and 20 W/cm[2] and 3.2 W/cm[2] for a clinical model, respectively. Individual irradiation of either IR or BL for 180 s induced the maximum temperatures of 62 ± 2 °C and 53 ± 3 °C on the biofilm, respectively. The simultaneous opto-chemical treatment reduced a significant population of the bacterial biofilms (7.5-log10 for Staphylococcus aureus and 7.1-log10 for Pseudomonas aeruginosa), which were 2.9-fold and 3.9-fold higher than that of the standard treatment with 2% glutaraldehyde (GA) solution, respectively. The proposed opto-chemical disinfection method can help reduce multi-drug resistant bacteria and prevent cross-infection during the clinical usage of a flexible endoscope.}, } @article {pmid34847463, year = {2021}, author = {Ohadi, E and Bakhshi, B and Kalani, BS and Talebi, M and Irajian, G}, title = {Transcriptome analysis of biofilm formation under aerobic and microaerobic conditions in clinical isolates of Campylobacter spp.}, journal = {Research in veterinary science}, volume = {142}, number = {}, pages = {24-30}, doi = {10.1016/j.rvsc.2021.11.009}, pmid = {34847463}, issn = {1532-2661}, abstract = {It has been well documented that Campylobacter is the leading cause of foodborne infections and bacterial enteritis in high-income countries. The gastrointestinal tract of most warm-blooded animals, such as mammals and poultry, is prone to this pathogen. Infections caused by this bacterium in humans have usually been associated with the consumption of contaminated poultry meat. The important point about Campylobacter is that this bacterium has adapted to harsh environmental conditions along the food chain (poultry digestive tract to the consumer's plate) and developed an adapted mechanism to those conditions. This study aimed to compare the ability of Campylobacter jejuni and Campylobacter coli strains to form biofilms under aerobic and microaerobic conditions. The presence and expression of flab, FliS, DnaK, luxs, CsrA, Cj0688, and cosR genes involved in biofilm formation were investigated. Finally, the correlation between the biofilm forming ability of Campylobacter isolates and the presence/expression of selected genes has been explored. A significant correlation was observed between the presence and expression of some genes and the degree of biofilm formation in C. jejuni and C. coli isolates. A strong biofilm production was detected in strains harboring all selected genes with greater expression levels. The ability of C. jejuni and C. coli strains in biofilm formation is associated with the coordinated function and convergent expression of the selected genes. Seemingly, stress response- and motility-related genes have the most involvement in biofilm formation of C. jejuni and C. coli strains, while other genes have an accessory role in this phenomenon.}, } @article {pmid34846850, year = {2021}, author = {Qiang, L and Cheng, J and Mirzoyan, S and Kerkhof, LJ and Häggblom, MM}, title = {Characterization of Microplastic-Associated Biofilm Development along a Freshwater-Estuarine Gradient.}, journal = {Environmental science & technology}, volume = {55}, number = {24}, pages = {16402-16412}, doi = {10.1021/acs.est.1c04108}, pmid = {34846850}, issn = {1520-5851}, mesh = {Biofilms ; Environmental Monitoring ; *Microbiota ; Microplastics ; Phylogeny ; Plastics ; Rivers ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microplastic contamination is an increasing concern worldwide. Biofilms rapidly develop on surfaces in aquatic habitats, but the processes of biofilm formation and variation in bacterial community succession on different microplastics introduced into freshwater and estuarine environments are not well understood. In this study, the biofilm bacterial communities that developed on three different types of microplastics that are prevalent in the environment, high-density polyethylene (HDPE), polyethylene terephthalate (PET), and polystyrene (PS), was investigated. Virgin microplastics were incubated in microcosms over a period of 31 days with water collected along a freshwater-estuarine gradient of the Raritan River in New Jersey. Through long-read MinION sequencing of bacterial ribosomal operons, we were able to examine biofilm bacterial communities at a species- and strain-level resolution. Results indicated that both salinity level and microplastic type impacted biofilm formation and promoted colonization by distinct microbial communities. Limnobacter thiooxidans was found to be one of the most abundant microplastics colonizing-bacteria, and it is hypothesized that different types of microplastics could select for different strains. Our findings indicate that multiple groups of highly similar L. thiooxidans rRNA operons could be discerned within the community profiles. Phylogenetic reconstruction further established that various Linmobacter species uniquely colonized the different microplastics from the different sampling sites. Our findings indicate that microplastics support abundant and diverse bacterial communities and that the various types of microplastics can influence how different bacterial biofilms develop, which may have ecological impacts on aquatic ecosystems.}, } @article {pmid34846510, year = {2021}, author = {He, W and Zheng, Z and Bai, H and Xiong, LH and Wang, L and Li, Y and Kwok, RTK and Lam, JWY and Hu, Q and Cheng, J and Tang, BZ}, title = {A biocompatible dual-AIEgen system without spectral overlap for quantitation of microbial viability and monitoring of biofilm formation.}, journal = {Materials horizons}, volume = {8}, number = {6}, pages = {1816-1824}, doi = {10.1039/d1mh00149c}, pmid = {34846510}, issn = {2051-6355}, mesh = {Biofilms ; *Boronic Acids ; Fluorescence ; *Fluorescent Dyes ; Humans ; Microbial Viability ; }, abstract = {The lack of rapid and reliable microbial detection and sensing platforms and insufficient understanding of microbial behavior may delay precautions that could be made, which is a great threat to human life and increases the heavy financial burden on society. In this contribution, a dual-aggregation-induced emission luminogen (AIEgen) system is successfully developed for microbial imaging and metabolic status sensing. This system consists of two AIEgens (DCQA and TPE-2BA) that bear positively charged groups or boronic acid groups, providing universal microbial staining ability and specific affinity for dead microbes, respectively. Based on the distinctive fluorescence response produced by the diverse interaction of AIEgens with live or dead microbes, this dual-AIEgen system can detect all the microbes and identify their viabilities. Furthermore, the morphology and metabolic status of a sessile biofilm can also be imaged and monitored. The system exhibits rapid labelling properties that suitable for various microbes, and good biocompatibilities.}, } @article {pmid34844745, year = {2022}, author = {Feizi, S and Cooksley, CM and Nepal, R and Psaltis, AJ and Wormald, PJ and Vreugde, S}, title = {Silver nanoparticles as a bioadjuvant of antibiotics against biofilm-mediated infections with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in chronic rhinosinusitis patients.}, journal = {Pathology}, volume = {54}, number = {4}, pages = {453-459}, doi = {10.1016/j.pathol.2021.08.014}, pmid = {34844745}, issn = {1465-3931}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Ciprofloxacin ; Clindamycin/pharmacology ; Doxycycline ; Gentamicins/pharmacology ; Humans ; *Metal Nanoparticles ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Silver/pharmacology ; Staphylococcus aureus ; Tobramycin/pharmacology ; }, abstract = {Infectious diseases caused by antibiotic-resistant bacteria in planktonic and biofilm form are difficult to treat with conventional antibiotics. Silver nanoparticles (Ag NPs) can be used as alternatives to antibiotics and can alter the susceptibility of bacteria to antibiotics. Here, the antibacterial properties of 16 different antibiotics and Ag NPs, alone and in combination, were tested against clinical isolates of Pseudomonas aeruginosa (n=3), Staphylococcus aureus (n=3) and methicillin-resistant Staphylococcus aureus (MRSA) (n=2) isolated from chronic rhinosinusitis (CRS) patients. The microdilution method and resazurin assay were used to determine the minimum inhibitory concentration and minimum biofilm eradication concentration for planktonic and biofilm forms, respectively. Results showed that Ag NPs and gentamicin combinations had synergistic antibacterial activity against P. aeruginosa planktonic and biofilm forms and MRSA biofilms. Furthermore, additive effects against biofilms were seen for combinations of Ag NPs with tobramycin or ciprofloxacin against P. aeruginosa; with mupirocin against MRSA; and with augmentin, doxycycline, azithromycin and clindamycin against S. aureus. Moreover, additive effects against planktonic forms were observed for combinations of Ag NPs with tobramycin, ciprofloxacin, imipenem, ceftazidime and aztreonam against P. aeruginosa; with gentamicin or linezolid against MRSA; and with doxycycline or clindamycin against S. aureus. In conclusion, Ag NP-antibiotic combinations can result in enhanced antimicrobial action against P. aeruginosa, MRSA and S. aureus clinical isolates in planktonic and biofilm forms and can be used in the context of CRS with confirmed infection.}, } @article {pmid34844301, year = {2022}, author = {Cui, X and Ren, Q and Zhang, J and Zhou, Y}, title = {Removal kinetics of linear alkylbenzene sulfonate in a batch-operated oxygen based membrane biofilm reactor treating greywater: Quantitative differentiation of adsorption and biodegradation.}, journal = {The Science of the total environment}, volume = {806}, number = {Pt 1}, pages = {150523}, doi = {10.1016/j.scitotenv.2021.150523}, pmid = {34844301}, issn = {1879-1026}, mesh = {Adsorption ; *Alkanesulfonic Acids ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; Cell Differentiation ; Kinetics ; Oxygen ; Sewage ; *Waste Disposal, Fluid ; }, abstract = {Oxygen-based membrane biofilm reactor (O2-MBfR) is a unique technique for high linear alkylbenzene sulfonate (LAS)-containing greywater (GW) treatment. Despite the efficient removal of LAS, the dynamics of how it is taken up and the quantitative differentiation of adsorption and biodegradation are largely undefined. In this study, we tracked the fate of LAS, chemical oxygen demand and nitrogen in various systems: GW, GW with inactivated sludge (InAS) and GW with activated sludge (AS). We determined the distribution of biodegraded-, free-, and extracellular polymeric substances (EPS)-attached LAS, and we also developed a model to simulate all the steps. Results showed that AS exhibited high live cells proportion and microbial activity, but the opposite trend for GW and InAS. Both of nitrogen and organics could be simultaneously and efficiently removed in the AS inoculated system. The two-step model for LAS uptake and biodegradation represented the experimental results well. EPS adsorption led to the fast LAS accumulation in biofilm, and biodegradation led to the continuous removal of LAS in the system. After operated for 24 h, biodegradation and EPS accumulation of LAS were 94% and 4%, respectively, and the residual soluble LAS was lower than 1%. This work lays the foundation for using O2-MBfR to treat GW and other types of wastewater, and understanding the key roles of EPS and the mathematical model of LAS removal in the system.}, } @article {pmid34843159, year = {2022}, author = {Chadha, J and Harjai, K and Chhibber, S}, title = {Repurposing phytochemicals as anti-virulent agents to attenuate quorum sensing-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbial biotechnology}, volume = {15}, number = {6}, pages = {1695-1718}, pmid = {34843159}, issn = {1751-7915}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Repositioning ; Phytochemicals/pharmacology ; *Pseudomonas aeruginosa/metabolism ; *Quorum Sensing ; Virulence Factors/genetics ; }, abstract = {Unregulated consumption and overexploitation of antibiotics have paved the way for emergence of antibiotic-resistant strains and 'superbugs'. Pseudomonas aeruginosa is among the opportunistic nosocomial pathogens causing devastating infections in clinical set-ups globally. Its artillery equipped with diversified virulence elements, extensive antibiotic resistance and biofilms has made it a 'hard-to-treat' pathogen. The pathogenicity of P. aeruginosa is modulated by an intricate cell density-dependent mechanism called quorum sensing (QS). The virulence artillery of P. aeruginosa is firmly controlled by QS genes, and their expression drives the aggressiveness of the infection. Attempts to identify and develop novel antimicrobials have seen a sharp rise in the past decade. Among different proposed mechanisms, a novel anti-virulence approach to target pseudomonal infections by virtue of anti-QS and anti-biofilm drugs appears to occupy the centre stage. In this respect, bioactive phytochemicals have gained prominence among the scientific community owing to their significant quorum quenching (QQ) properties. Recent studies have shed light on the QQ activities of various phytochemicals and other drugs in perturbing the QS-dependent virulence in P. aeruginosa. This review highlights the recent evidences that reinforce the application of plant bioactives for combating pseudomonal infections, their advantages and shortcomings in anti-virulence therapy.}, } @article {pmid34842640, year = {2021}, author = {Gaire, U and Thapa Shrestha, U and Adhikari, S and Adhikari, N and Bastola, A and Rijal, KR and Ghimire, P and Banjara, MR}, title = {Antibiotic Susceptibility, Biofilm Production, and Detection of mecA Gene among Staphylococcus aureus Isolates from Different Clinical Specimens.}, journal = {Diseases (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {34842640}, issn = {2079-9721}, abstract = {The increasing incidence of methicillin-resistant and biofilm-forming S. aureus isolates in hospital settings is a gruesome concern today. The main objectives of this study were to determine the burden of S. aureus in clinical samples, assess their antibiotic susceptibility pattern and detect biofilm formation and mecA gene in them. A total of 1968 different clinical specimens were processed to isolate S. aureus following standard microbiological procedures. Antibiotic susceptibility test of the isolates was performed by Kirby-Bauer disc-diffusion method following CLSI guidelines. Biofilm was detected through tissue culture plate method. Methicillin-resistant S. aureus (MRSA) isolates were screened using cefoxitin (30 µg) discs and mecA gene was amplified by conventional polymerase chain reaction (PCR). Of 177 bacterial growth, the prevalence of S. aureus was 15.3% (n = 27). MRSA were 55.6% (15/27) and 44% (12/27) exhibited multidrug resistance (MDR). There was no significant association between methicillin resistance and MDR (p > 0.05). Both MRSA and MSSA were least sensitive to penicillin (100%, 75%) followed by erythromycin (86.6%, 66.6%). Most of the MRSA (93.4%) were susceptible to tetracycline. All S. aureus isolates were biofilm producers-19 (70%) were weak and only one (4%) was a strong biofilm producer. The strong biofilm-producing MSSA was resistant to most of the antibiotics except cefoxitin and clindamycin. None of the MSSA possessed mecA gene while 8 (53.3%) MRSA had it. More than half of S. aureus isolated were MRSA. High incidence of multidrug resistance along with capacity to form biofilm among clinical isolates of S.aureus is a matter of apprehension and prompt adoption of biosafety measures is suggested to curb their dissemination in the hospital environments.}, } @article {pmid34841350, year = {2021}, author = {Iribarnegaray, V and González, MJ and Caetano, AL and Platero, R and Zunino, P and Scavone, P}, title = {Relevance of iron metabolic genes in biofilm and infection in uropathogenic Proteus mirabilis.}, journal = {Current research in microbial sciences}, volume = {2}, number = {}, pages = {100060}, pmid = {34841350}, issn = {2666-5174}, abstract = {The microorganisms are found in the environment, forming sessile communities embedded in an extracellular matrix of their own production, called biofilm. These communities have a great relevance in the clinical context, since they are associated with infections caused by biofilm in medical implants, such as urinary catheters. The development of biofilms is a complex process where a great diversity of genes participate. The present work is based on the study of genes related to iron metabolism and its implication in the development of P. mirabilis biofilms and pathogenicity. For this study, two mutant strains defective in biofilm formation were selected, generated by the interruption of genes that encoded non-heme ferritin and TonB-dependent receptor. The mutations influence on the development of the biofilm was evaluated by different approaches. The complexity of the biofilm was analyzed using Confocal Laser Microscopy and image analysis. The mutants infectivity potential was assessed in two experimental mice models of urinary tract infection. The results obtained in the present work show us the role of the ferritin and a TonB-associated porin protein over the initial and later stages of biofilm development. Moreover, in the ascending UTI mouse model, both mutants failed to colonize the urinary tract. In CAUTI models, ferritin mutant damaged the bladder similarly to wild type but the Ton-B mutant was unable to generate infection in the urinary tract. The results obtained in the present work confirm the relevant role that iron metabolism genes have in P. mirabilis biofilm development and for infection in the urinary tract.}, } @article {pmid34839774, year = {2021}, author = {Du, Q and Yuan, S and Zhao, S and Fu, D and Chen, Y and Zhou, Y and Cao, Y and Gao, Y and Xu, X and Zhou, X and He, J}, title = {Coexistence of Candida albicans and Enterococcus faecalis increases biofilm virulence and periapical lesions in rats.}, journal = {Biofouling}, volume = {37}, number = {9-10}, pages = {964-974}, doi = {10.1080/08927014.2021.1993836}, pmid = {34839774}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; *Candida albicans ; *Enterococcus faecalis ; Rats ; Virulence ; }, abstract = {The present study utilized an in vitro dual-species biofilm model and an in vivo rat post-treatment endodontic disease (PTED) model to investigate whether co-infection of Candida albicans and Enterococcus faecalis would aggravate periapical lesions. The results showed that co-culturing yielded a thicker and denser biofilm more tolerant to detrimental stresses compared with the mono-species biofilm, such as a starvation-alkalinity environment, mechanical shear force and bactericidal chemicals. Consistently, co-inoculation of E. faecalis and C. albicans significantly increased the extent of in vivo periapical lesions compared with mono-species infection. Specifically, coexistence of both microorganisms increased osteoclastic bone resorption and suppressed osteoblastic bone formation. The synergistic effects also up-regulated inflammatory cytokines including TNF-α and IL-6. In summary, coexistence of C. albicans and E. faecalis increased periapical lesions by enhanced biofilm virulence.}, } @article {pmid34838838, year = {2022}, author = {Song, X and Jo, C and Zhou, M}, title = {Enhanced electricity generation and tetracycline removal of bioelectro-Fenton with electroactive biofilm induced by multi external resistance.}, journal = {Chemosphere}, volume = {289}, number = {}, pages = {133070}, doi = {10.1016/j.chemosphere.2021.133070}, pmid = {34838838}, issn = {1879-1298}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Hydrogen Peroxide ; Tetracycline ; }, abstract = {A simple multi electric resistance mode is used to regulate electroactive anode film, which improves the electricity generation, H2O2 production and pollutants removal. This external electron transport path (double cathode with different resistance) exhibits higher H2O2 production (571.9 ± 0.1 mg m[-2] h[-1]), tetracycline removal (71.4 ± 0.4% to 50 mg L[-1]), and power (615.3 ± 9.9 mW m[-2] plus 680.6 ± 10.3 mW m[-2]), which is 75.4%, 23.1% and 1.25 times higher than that of single cathode mode. The double cathode improves the relative abundance of Geobacter (exoelectrogens), which is 9.45 times higher than that of single cathode mode. The anodic capacitance of double cathode mode is more than 10 times higher than that of single cathode mode. Electrons (generate by exoelectrogens) participate in two- (cathodic chamber) and four- (anodic chamber) electron reaction at cathode surface, and facilitates electricity generation of bioelectro-Fenton. The removal rate of double cathode mode is 342.7 mg L[-1] d[-1] (50 mg L[-1] tetracycline) and 170.1 mg L[-1] d[-1] (20 mg L[-1] tetracycline), which is much higher than that of reported. These results indicate that external electron transport path enhances the electrochemical activity of anode film and performance of bioelectro-Fenton. This paper provides a new power supply method for the future practical application and field experiment of bioelectrio-Fenton.}, } @article {pmid34838558, year = {2022}, author = {Zhu, L and Yuan, H and Shi, Z and Deng, L and Yu, Z and Li, Y and He, Q}, title = {Metagenomic insights into the effects of various biocarriers on moving bed biofilm reactors for municipal wastewater treatment.}, journal = {The Science of the total environment}, volume = {813}, number = {}, pages = {151904}, doi = {10.1016/j.scitotenv.2021.151904}, pmid = {34838558}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors ; Denitrification ; Nitrification ; Nitrogen/analysis ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid ; Wastewater/analysis ; *Water Purification ; }, abstract = {Preferable biocarrier is vital for start-up and operation of moving bed biofilm reactor (MBBR). Effects of three separate biocarriers - PPC, PU, and PP on MBBRs were systematically investigated including nutrients removal performances, biomass attachment, microbial community, and relevant functional genes. Results showed that three biocarriers achieved similar removal efficiencies for chemical oxygen demand (COD) and total phosphorus (TP), though much higher biomasses were found attached onto PPC and PU carriers. PPC and PU performed better than PP for ammonia nitrogen (NH4[+]-N) removal. However, PPC exhibited the greatest and most reliable denitrifying efficiency, mainly due to stronger simultaneous nitrification and denitrification during better micro-anoxic-environment created within PPC carriers than others. Further studies by 16S rRNA gene and metagenomic sequencing analysis uncovered the bacterial diversity and structures, and relevant functional genes for nitrogen-transformation and pathways of nitrogen metabolisms, which laid the biological basis for the best performances via biocarrier PPC. This study inspired a feasible approach for municipal wastewater treatment through PPC filled MBBR.}, } @article {pmid34838388, year = {2022}, author = {Li, N and Li, X and Fan, XY}, title = {Storage tank as a pretreatment unit for rainwater cleaner production: Role of biofilm bacterial communities and functional genera in water quality improvement.}, journal = {Journal of environmental management}, volume = {303}, number = {}, pages = {114118}, doi = {10.1016/j.jenvman.2021.114118}, pmid = {34838388}, issn = {1095-8630}, mesh = {Ammonia ; *Bacteria/genetics ; Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; *Quality Improvement ; Water Quality ; }, abstract = {This study investigated the water purification function and mechanism of biofilm in storage tank, with a view to using it as a pretreatment unit for rainwater cleaner production. Shortening the hydraulic retention time (HRT) of storage tank from 12 to 4 h improved the pollutants removal performance and reduced the suspended bacteria counts. The accumulation of abundant taxa and succession of rare taxa were observed with biofilm development. Positive correlations within and across different bacterial taxa were dominant in the network, and some rare genera (Ralstonia and Micropruina) were identified as hub bacteria. Candidatus Nitrospira nitrosa and Nitrospira sp. ENR4 were two identified complete ammonia oxidizers. Denitrifying bacteria tended to enrich and formed more complex interactions over time. The main nitrogen metabolism pathways may be ammonia assimilatory, complete denitrification and dissimilatory/assimilatory nitrate reduction. HRT was negatively correlated with most dominant genera, and contributed 20.35% to the variation of functional taxa. This study highlights the self-purification function and micro-ecology of storage tank, and provides a new insight for its role in rainwater cleaner production process.}, } @article {pmid34837552, year = {2021}, author = {Tan, X and Cheng, X and Hu, M and Zhang, Y and Jia, A and Zhou, J and Zhu, G}, title = {Transcriptional analysis and target genes discovery of Pseudomonas aeruginosa biofilm developed ex vivo chronic wound model.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {157}, pmid = {34837552}, issn = {2191-0855}, support = {2108085QC92//Natural Science Foundation of Anhui Province/ ; KJ2019A0505//University Natural Science Research Project of Anhui Province/ ; fzmx202005//opening object of Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases/ ; 202010370211//Innovation Training Program for University Students/ ; 32000091//Young Scientists Fund/ ; 20KJB180019//General Projects of Natural Science Research in Universities of Jiangsu Province/ ; }, abstract = {Bacterial biofilms formation is one of the major reasons for treatment failure in chronic wound infections. Therefore, diagnostic biomarkers remain the best option for prevention and treatment of chronic wound infections by biofilms. Herein, Pseudomonas aeruginosa PAO1 was used to mimic biofilm development in porcine skin explants wells as ex vivo wound model. The microscopic imaging showed that PAO1 in porcine skin explants wells formed micro-colonies at 24 h, developed mushroom-like structure at 48 h, and at 72 h mushroom-like structure disappeared, remaining a thin bacterial lawn. RNA-seq data analysis revealed that the expression levels of genes involved in the type II hxc secretion system were significantly higher in biofilms than in planktonic cells, especially the expression of lapA encoding alkaline phosphatase. However, the expression levels of genes associated with denitrification pathway were markedly decreased in biofilms, especially the transcription of nirS encoding nitrite reductase to produce nitric oxide (NO). Therefore, their expressions and products were further detected using RT-qPCR and biochemical assays, respectively. The results found that the expression of lapA and alkaline phosphatase activity were induced, but the expression of nirS and intracellular NO were reduced at the whole biofilms cycle. The study indicates that LapA and NO would play an important role for P. aeruginosa biofilm formation in chronic wound infections. LapA would serve as potential target to monitor chronic wound infections by P. aeruginosa biofilms. Inducing NO would be used to treat chronic wound infections due to P. aeruginosa biofilms.}, } @article {pmid34836818, year = {2022}, author = {Souza, BDO and Arcos, JJE and Nakamura, CV and Nagashima, LA and Sano, A and Ono, MA and Itano, EN}, title = {In vitro Arthrographis kalrae biofilm formation: Scanning electron microscopy and cytotoxic analysis.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {55}, number = {5}, pages = {973-976}, doi = {10.1016/j.jmii.2021.11.002}, pmid = {34836818}, issn = {1995-9133}, mesh = {Humans ; Microscopy, Electron, Scanning ; *Ascomycota ; Biofilms ; Plant Extracts ; }, abstract = {To our knowledge, this study represents the first demonstration of Arthrographis kalrae biofilm formation in vitro by scanning electron microscopy and the distinct cytotoxic activity between planktonic and biofilm extracts on RAW 264.7 cell line. Higher activity was observed with biofilm. It could impact host immune response, that require furthers study.}, } @article {pmid34836285, year = {2021}, author = {Kurz, H and Karygianni, L and Argyropoulou, A and Hellwig, E and Skaltsounis, AL and Wittmer, A and Vach, K and Al-Ahmad, A}, title = {Antimicrobial Effects of Inula viscosa Extract on the In Situ Initial Oral Biofilm.}, journal = {Nutrients}, volume = {13}, number = {11}, pages = {}, pmid = {34836285}, issn = {2072-6643}, support = {AL 1179/4-1//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Bacteria/drug effects ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Colony Count, Microbial ; Inula/*chemistry ; Microbial Viability/drug effects ; Microscopy, Fluorescence ; Mouth/microbiology ; Mouthwashes ; Plant Extracts/*pharmacology ; }, abstract = {Given the undesirable side effects of commercially used mouth rinses that include chemically synthesized antimicrobial compounds such as chlorhexidine, it is essential to discover novel antimicrobial substances based on plant extracts. The aim of this study was to examine the antimicrobial effect of Inula viscosa extract on the initial microbial adhesion in the oral cavity. Individual test splints were manufactured for the participants, on which disinfected bovine enamel samples were attached. After the initial microbial adhesion, the biofilm-covered oral samples were removed and treated with different concentrations (10, 20, and 30 mg/mL) of an I. viscosa extract for 10 min. Positive and negative controls were also sampled. Regarding the microbiological parameters, the colony-forming units (CFU) and vitality testing (live/dead staining) were examined in combination with fluorescence microscopy. An I. viscosa extract with a concentration of 30 mg/mL killed the bacteria of the initial adhesion at a rate of 99.99% (log10 CFU value of 1.837 ± 1.54). Compared to the negative control, no killing effects were determined after treatment with I. viscosa extract at concentrations of 10 mg/mL (log10 CFU value 3.776 ± 0.831; median 3.776) and 20 mg/mL (log10 CFU value 3.725 ± 0.300; median 3.711). The live/dead staining revealed a significant reduction (p < 0.0001) of vital adherent bacteria after treatment with 10 mg/mL of I. viscosa extract. After treatment with an I. viscosa extract with a concentration of 30 mg/mL, no vital bacteria could be detected. For the first time, significant antimicrobial effects on the initial microbial adhesion in in situ oral biofilms were reported for an I. viscosa extract.}, } @article {pmid34835911, year = {2021}, author = {Ivanova, A and Ivanova, K and Tzanov, T}, title = {Simultaneous Ultrasound-Assisted Hybrid Polyzwitterion/Antimicrobial Peptide Nanoparticles Synthesis and Deposition on Silicone Urinary Catheters for Prevention of Biofilm-Associated Infections.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {34835911}, issn = {2079-4991}, support = {PID2019-104111RB-I00//Spanish Ministry of Economy and Competitiveness Projects (MINECO)/ ; PCI2021-121926//Ministerio de Economía y Competitividad (MINECO), under the three Joint Programming Initiatives (JPIs) on Water, Oceans and Antimicrobial Resistance (AMR) - JPIAMR/ ; }, abstract = {Nosocomial infections caused by antibiotic-resistant bacteria are constantly growing healthcare threats, as they are the reason for the increased mortality, morbidity, and considerable financial burden due to the poor infection outcomes. Indwelling medical devices, such as urinary catheters, are frequently colonized by bacteria in the form of biofilms that cause dysfunction of the device and severe chronic infections. The current treatment strategies of such device-associated infections are impaired by the resistant pathogens but also by a risk of prompting the appearance of new antibiotic-resistant bacterial mechanisms. Herein, the one-step sonochemical synthesis of hybrid poly(sulfobetaine) methacrylate/Polymyxin B nanoparticles (pSBMA@PM NPs) coating was employed to engineer novel nanoenabled silicone catheters with improved antifouling, antibacterial, and antibiofilm efficiencies. The synergistic mode of action of nanohybridized zwitterionic polymer and antimicrobial peptide led to complete inhibition of the nonspecific protein adsorption and up to 97% reduction in Pseudomonas aeruginosa biofilm formation, in comparison with the pristine silicone. Additionally, the bactericidal activity in the hybrid coating reduced the free-floating and surface-attached bacterial growth by 8 logs, minimizing the probability for further P. aeruginosa spreading and host invasion. This coating was stable for up to 7 days under conditions simulating the real scenario of catheter usage and inhibited by 80% P. aeruginosa biofilms. For the same time of use, the pSBMA@PM NPs coating did not affect the metabolic activity and morphology of mammalian cells, demonstrating their capacity to control antibiotic-resistant biofilm-associated bacterial infections.}, } @article {pmid34835692, year = {2021}, author = {Wang, L and Liu, L and Zhou, X}, title = {Bacitracin-Ag Nanoclusters as a Novel Antibacterial Agent Combats Shigella flexneri by Disrupting Cell Membrane and Inhibiting Biofilm Formation.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {34835692}, issn = {2079-4991}, support = {2021QFY07-04//Shaanxi Province Technology Innovation Guidance Special Plan/ ; }, abstract = {A novel nanomaterial Bacitracin-Ag Nanoclusters (Bacitracin-AgNCs) was formed to achieve a better antibacterial effect on Shigella flexneri which poses a serious threat to human health. In the current study, X-ray photoelectron spectrometer (XPS), Fourier transform infrared (FTIR), field-emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HR-TEM) and thermal gravimetric analysis (TGA) were used to characterize the properties of composited Bacitracin-AgNCs. Furthermore, the inhibitory effects of Bacitracin-AgNCs against S. flexneri were explored, and the inhibition mechanism was discussed in terms of its aspects of cell membrane ravage, ATPase activity decline and biofilm inhibition. The results reveal that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Bacitracin-AgNCs against S. flexneri were 0.03 mg/mL and 4 mg/mL. Bacitracin-AgNCs may cause irreversible impairment to cells and greatly change the cell morphology. The cell membrane integrity of S. flexneri was destroyed with changes in the characteristics of membrane permeability and intracellular substances leakage. Moreover, our study further proved that Bacitracin-AgNCs significantly inhibited the formation of S. flexneri biofilms and reduced the number of viable bacteria in biofilm. These findings provide a potential method for the exploitation of organic composite nanomaterials as a novel antimicrobial agent and its application in the food industry.}, } @article {pmid34835563, year = {2021}, author = {Alali, AQ and Abdal-Hay, A and Gulati, K and Ivanovski, S and Fournier, BPJ and Lee, RSB}, title = {Influence of Bioinspired Lithium-Doped Titanium Implants on Gingival Fibroblast Bioactivity and Biofilm Adhesion.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {34835563}, issn = {2079-4991}, support = {2804-2020//Australian Dental research foundation/ ; }, abstract = {Soft tissue integration (STI) at the transmucosal level around dental implants is crucial for the long-term success of dental implants. Surface modification of titanium dental implants could be an effective way to enhance peri-implant STI. The present study aimed to investigate the effect of bioinspired lithium (Li)-doped Ti surface on the behaviour of human gingival fibroblasts (HGFs) and oral biofilm in vitro. HGFs were cultured on various Ti surfaces-Li-doped Ti (Li_Ti), NaOH_Ti and micro-rough Ti (Control_Ti)-and were evaluated for viability, adhesion, extracellular matrix protein expression and cytokine secretion. Furthermore, single species bacteria (Staphylococcus aureus) and multi-species oral biofilms from saliva were cultured on each surface and assessed for viability and metabolic activity. The results show that both Li_Ti and NaOH_Ti significantly increased the proliferation of HGFs compared to the control. Fibroblast growth factor-2 (FGF-2) mRNA levels were significantly increased on Li_Ti and NaOH_Ti at day 7. Moreover, Li_Ti upregulated COL-I and fibronectin gene expression compared to the NaOH_Ti. A significant decrease in bacterial metabolic activity was detected for both the Li_Ti and NaOH_Ti surfaces. Together, these results suggest that bioinspired Li-doped Ti promotes HGF bioactivity while suppressing bacterial adhesion and growth. This is of clinical importance regarding STI improvement during the maintenance phase of the dental implant treatment.}, } @article {pmid34835515, year = {2021}, author = {Kodeš, Z and Vrublevskaya, M and Kulišová, M and Jaroš, P and Paldrychová, M and Pádrová, K and Lokočová, K and Palyzová, A and Maťátková, O and Kolouchová, I}, title = {Composition and Biological Activity of Vitis vinifera Winter Cane Extract on Candida Biofilm.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835515}, issn = {2076-2607}, support = {18-26463S//Czech Science Foundation/ ; }, abstract = {Vitis vinifera canes are waste material of grapevine pruning and thus represent cheap source of high-value polyphenols. In view of the fact that resistance of many pathogenic microorganisms to antibiotics is a growing problem, the antimicrobial activity of plant polyphenols is studied as one of the possible approaches. We have investigated the total phenolic content, composition, antioxidant activity, and antifungal activity against Candida biofilm of an extract from winter canes and a commercially available extract from blue grapes. Light microscopy and confocal microscopy imaging as well as crystal violet staining were used to quantify and visualize the biofilm. We found a decrease in cell adhesion to the surface depending on the concentration of resveratrol in the cane extract. The biofilm formation was observed as metabolic activity of Candida albicans, Candida parapsilosis and Candida krusei biofilm cells and the minimum biofilm inhibitory concentrations were determined. The highest inhibition of metabolic activity was observed in Candida albicans biofilm after treatment with the cane extract (30 mg/L) and blue grape extract (50 mg/L). The composition of cane extract was analyzed and found to be comparatively different from blue grape extract. In addition, the content of total phenolic groups in cane extract was three-times higher (12.75 gGA/L). The results showed that cane extract was more effective in preventing biofilm formation than blue grape extract and winter canes have proven to be a potential source of polyphenols for antimicrobial and antibiofilm treatment.}, } @article {pmid34835509, year = {2021}, author = {Donadu, MG and Mazzarello, V and Cappuccinelli, P and Zanetti, S and Madléna, M and Nagy, ÁL and Stájer, A and Burián, K and Gajdács, M}, title = {Relationship between the Biofilm-Forming Capacity and Antimicrobial Resistance in Clinical Acinetobacter baumannii Isolates: Results from a Laboratory-Based In Vitro Study.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835509}, issn = {2076-2607}, abstract = {The relationship between the multidrug-resistant (MDR) phenotype and biofilm-forming capacity has been a topic of extensive interest among biomedical scientists, as these two factors may have significant influence on the outcomes of infections. The aim of the present study was to establish a possible relationship between biofilm-forming capacity and the antibiotic-resistant phenotype in clinical Acinetobacter baumannii (A. baumannii) isolates. A total of n = 309 isolates were included in this study. Antimicrobial susceptibility testing and the phenotypic detection of resistance determinants were carried out. The capacity of isolates to produce biofilms was assessed using a crystal violet microtiter-plate-based method. Resistance rates were highest for ciprofloxacin (71.19%; n = 220), levofloxacin (n = 68.61%; n = 212), and trimethoprim-sulfamethoxazole (n = 66.02%; n = 209); 42.72% (n = 132) of isolates were classified as MDR; 22.65% (n = 70) of tested isolates were positive in the modified Hodge-test; the overexpression of efflux pumps had significant effects on the susceptibilities of meropenem, gentamicin, and ciprofloxacin in 14.24% (n = 44), 6.05% (n = 19), and 27.51% (n = 85), respectively; 9.39% (n = 29), 12.29% (n = 38), 22.97% (n = 71), and 55.35% (n = 170) of isolates were non-biofilm-producing and weak, moderate, and strong biofilm producers, respectively. A numerical, but statistically not significant, difference was identified between the MDR and non-MDR isolates regarding their biofilm-forming capacity (MDR: 0.495 ± 0.309 vs. non-MDR: 0.545 ± 0.283; p = 0.072), and no association was seen between resistance to individual antibiotics and biofilm formation. Based on numerical trends, MER-resistant isolates were the strongest biofilm producers (p = 0.067). Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of A. baumannii infections.}, } @article {pmid34835490, year = {2021}, author = {Khalil, MAF and Ahmed, FA and Elkhateeb, AF and Mahmoud, EE and Ahmed, MI and Ahmed, RI and Hosni, A and Alghamdi, S and Kabrah, A and Dablool, AS and Hetta, HF and Moawad, SS and Hefzy, EM}, title = {Virulence Characteristics of Biofilm-Forming Acinetobacter baumannii in Clinical Isolates Using a Galleria mellonella Model.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835490}, issn = {2076-2607}, abstract = {Acinetobacter baumannii is a Gram-negative coccobacillus responsible for severe hospital-acquired infections, particularly in intensive care units (ICUs). The current study was designed to characterize the virulence traits of biofilm-forming carbapenem-resistant A. baumannii causing pneumonia in ICU patients using a Galleria mellonella model. Two hundred and thirty patients with hospital-acquired or ventilator-associated pneumonia were included in our study. Among the total isolates, A. baumannii was the most frequently isolated etiological agent in ICU patients with pneumonia (54/165, 32.7%). All A. baumannii isolates were subjected to antimicrobial susceptibility testing by the Kirby-Bauer disk diffusion method, while the minimum inhibitory concentrations of imipenem and colistin were estimated using the broth microdilution technique. The biofilm formation activity of the isolates was tested using the microtiter plate technique. Biofilm quantification showed that 61.1% (33/54) of the isolates were strong biofilm producers, while 27.7% (15/54) and 11.1% (6/54) showed moderate or weak biofilm production. By studying the prevalence of carbapenemases-encoding genes among isolates, blaOXA-23-like was positive in 88.9% of the isolates (48/54). The BlaNDM gene was found in 27.7% of the isolates (15/54 isolates). BlaOXA-23-like and blaNDM genes coexisted in 25.9% (14/54 isolates). Bap and blaPER-1 genes, the biofilm-associated genes, coexisted in 5.6% (3/54) of the isolates. For in vivo assessment of A. baumannii pathogenicity, a Galleria mellonella survival assay was used. G. mellonella survival was statistically different between moderate and poor biofilm producers (p < 0.0001). The killing effect of the strong biofilm-producing group was significantly higher than that of the moderate and poor biofilm producers (p < 0.0001 for each comparison). These findings highlight the role of biofilm formation as a powerful virulence factor for carbapenem-resistant A. baumannii that causes pneumonia in the ICU.}, } @article {pmid34835474, year = {2021}, author = {Tazi, N and Pigeon, X and Mbuyi-Boisvert, JM and Giret, S and Béland, F and Rouabhia, M}, title = {Effect of Cannabis Smoke Condensate on C. albicans Growth and Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835474}, issn = {2076-2607}, abstract = {The most common use of cannabis is smoking. The oral ecosystem, among other constituents, can be deregulated by the presence of cannabis smoke in the oral cavity. We evaluated the effect of cannabis smoke condensate (CSC) on the behavior of Candida albicans, a common yeast found in the oral cavity. The yeast was first cultured with different concentrations of CSC, and its growth was evaluated. The transition from the blastospore to the hyphal form and the hyphae size were assessed after 3 and 6 h, along with biofilm formation after 72 h of contact with CSC. The response of C. albicans to oxidative (H2O2) stress was also examined. Our results show that CSC contained high amounts of THC (about 1055 ppm), CBN (63 ppm), and CBG (about 47 ppm). The presence of various concentrations of CSC in the culture medium increased C. albicans growth. CSC also contributed to increases in both the hyphal length and biofilm mass. Following oxidative stress (H2O2 at either 100 or 500 μM), CSC prevented the damaging effect of H2O2 on both C. albicans shape and growth. These findings support clinical observations demonstrating that cannabis may promote C.&nbsp;albicans growth and oral candidiasis.}, } @article {pmid34835462, year = {2021}, author = {Gao, J and Han, Z and Li, P and Zhang, H and Du, X and Wang, S}, title = {Outer Membrane Protein F Is Involved in Biofilm Formation, Virulence and Antibiotic Resistance in Cronobacter sakazakii.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835462}, issn = {2076-2607}, support = {31972167//National Natural Science Foundation of China/ ; }, abstract = {In some Gram-negative bacteria, ompF encodes outer membrane protein F (OmpF), which is a cation-selective porin and is responsible for the passive transport of small molecules across the outer membrane. However, there are few reports about the functions of this gene in Cronobacter sakazakii. To investigate the role of ompF in detail, an ompF disruption strain (ΔompF) and a complementation strain (cpompF) were successfully obtained. We find that OmpF can affect the ability of biofilm formation in C. sakazakii. In addition, the variations in biofilm composition of C. sakazakii were examined using Raman spectroscopy analyses caused by knocking out ompF, and the result indicated that the levels of certain biofilm components, including lipopolysaccharide (LPS), were significantly decreased in the mutant (ΔompF). Then, SDS-PAGE was used to further analyze the LPS content, and the result showed that the LPS levels were significantly reduced in the absence of ompF. Therefore, we conclude that OmpF affects biofilm formation in C. sakazakii by reducing the amount of LPS. Furthermore, the ΔompF mutant showed decreased (2.7-fold) adhesion to and invasion of HCT-8 cells. In an antibiotic susceptibility analysis, the ΔompF mutant showed significantly smaller inhibition zones than the WT, indicating that OmpF had a positive effect on the influx of antibiotics into the cells. In summary, ompF plays a positive regulatory role in the biofilm formation and adhesion/invasion, which is achieved by regulating the amount of LPS, but is a negative regulator of antibiotic resistance in C. sakazakii.}, } @article {pmid34835400, year = {2021}, author = {Soto-Aguilera, S and Modak, B and Aldabaldetrecu, M and Lozano, CP and Guerrero, J and Lefimil, C and Parra, M}, title = {In Vitro Effect of Copper (I) Complex [Cu(NN1)2](ClO4) on Vibrio harveyi BB170 Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835400}, issn = {2076-2607}, abstract = {Biofilm formation in pathogenic bacteria is an important factor of resistance to antimicrobial treatments, allowing them to survive for a long time in their hosts. In the search for new antibiofilm agents, in this work we report the activity of a copper (I) complex, [Cu(NN1)2]ClO4, synthesized with Cu (I) and NN1, an imine ligand 6-((quinolin-2-ylmethylene)amino)-2H-chromen-2-one, a derivate of natural compound coumarin. The antibacterial and antibiofilm capacity was evaluated in Vibrio harveyi BB170 used as model bacteria. Antibacterial activity was measured in vitro by minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and half-maximal inhibitory concentration (IC50) determination. Antibiofilm capacity of copper (I) complex was analyzed by different concentrations of IC50 values. The results showed that the sub-IC50 concentration, 12.6 µg/mL of the copper (I) complex, was able to reduce biofilm formation by more than 75%, and bacterial viability was reduced by 50%. Inverted and confocal laser scanning microscopy showed that the [Cu(NN1)2]ClO4 complex affected the biofilm structure. Therefore, the copper (I) complex is effective as an antibiofilm compound in V. harveyi BB170.}, } @article {pmid34835399, year = {2021}, author = {Abd El Rahman, A and El Kholy, Y and Shash, RY}, title = {Correlation between mazEF Toxin-Antitoxin System Expression and Methicillin Susceptibility in Staphylococcus aureus and Its Relation to Biofilm-Formation.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835399}, issn = {2076-2607}, support = {PCR kits//Cairo University hospitals/ ; PCR kits//Cairo University hospitals/ ; }, abstract = {Methicillin resistance in Staphylococcus aureus has become prevalent globally. Moreover, biofilm-formation makes it more difficult to eradicate bacteria by antibiotics. The mazEF toxin-antitoxin system encodes for mazF, which acts as an endoribonuclease that cleaves cellular mRNAs at specific sequence motifs (ACA), and mazE, which opposes the mazF action. Our goal was to detect mazEF expression in methicillin-resistant S. aureus (MRSA) isolates compared with methicillin-sensitive S. aureus (MSSA) isolates and determine its relation to methicillin susceptibility as well as biofilm-formation. According to their susceptibility to cefoxitin disks, 100 S. aureus isolates obtained from patients admitted to Cairo University Hospitals were categorized into 50 MSSA and 50 MRSA according to their susceptibility to cefoxitin disks (30 µg). Antimicrobial susceptibility and biofilm-formation were investigated using the disk diffusion method and tissue culture plate method, respectively. Finally, using real-time PCR, mazEF expression was estimated and correlated to methicillin susceptibility and biofilm formation. Both MRSA and MSSA isolates showed the best sensitivity results with linezolid and gentamicin, where about 88% of MRSA isolates and 96% of MSSA isolates were sensitive to linezolid while 76% of MRSA isolates and 84% of MSSA isolates were sensitive to gentamicin. MRSA isolates were significantly more able to form biofilm than MSSA isolates (p-value = 0.037). The mazEF expression was significantly correlated to methicillin resistance in S. aureus (p-value < 0.001), but not to biofilm-formation.}, } @article {pmid34835375, year = {2021}, author = {Stoll, A and Salvatierra-Martínez, R and González, M and Araya, M}, title = {The Role of Surfactin Production by Bacillus velezensis on Colonization, Biofilm Formation on Tomato Root and Leaf Surfaces and Subsequent Protection (ISR) against Botrytis cinerea.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835375}, issn = {2076-2607}, support = {BIP 30403034//Regional Fund of Innovation for Competitiveness Coquimbo Region FIC-R, Chile/ ; BIP 30127532//Regional Fund of Innovation for Competitiveness Coquimbo Region FIC-R, Chile/ ; 21140504//Agencia Nacional de Investigación y Desarrollo/ ; }, abstract = {Many aspects regarding the role of lipopeptides (LPs) in bacterial interaction with plants are not clear yet. Of particular interest is the LP family of surfactin, immunogenic molecules involved in induced systemic resistance (ISR) and the bacterial colonization of plant surfaces. We hypothesize that the concentration of surfactin produced by a strain correlates directly with its ability to colonize and persist on different plant surfaces, which conditions its capacity to trigger ISR. We used two Bacillus velezensis strains (BBC023 and BBC047), whose antagonistic potential in vitro is practically identical, but not on plant surfaces. The surfactin production of BBC047 is 1/3 higher than that of BBC023. Population density and SEM images revealed stable biofilms of BBC047 on leaves and roots, activating ISR on both plant surfaces. Despite its lower surfactin production, strain BBC023 assembled stable biofilms on roots and activated ISR. However, on leaves only isolated, unstructured populations were observed, which could not activate ISR. Thus, the ability of a strain to effectively colonize a plant surface is not only determined through its production of surfactin. Multiple aspects, such as environmental stressors or compensation mechanisms may influence the process. Finally, the importance of surfactin lies in its impacts on biofilm formation and stable colonization, which finally enables its activity as an elicitor of ISR.}, } @article {pmid34835318, year = {2021}, author = {Leroy, S and Lebert, I and Andant, C and Micheau, P and Talon, R}, title = {Investigating Extracellular DNA Release in Staphylococcus xylosus Biofilm In Vitro.}, journal = {Microorganisms}, volume = {9}, number = {11}, pages = {}, pmid = {34835318}, issn = {2076-2607}, abstract = {Staphylococcus xylosus forms biofilm embedded in an extracellular polymeric matrix. As extracellular DNA (eDNA) resulting from cell lysis has been found in several staphylococcal biofilms, we investigated S. xylosus biofilm in vitro by a microscopic approach and identified the mechanisms involved in cell lysis by a transcriptomic approach. Confocal laser scanning microscopy (CLSM) analyses of the biofilms, together with DNA staining and DNase treatment, revealed that eDNA constituted an important component of the matrix. This eDNA resulted from cell lysis by two mechanisms, overexpression of phage-related genes and of cidABC encoding a holin protein that is an effector of murein hydrolase activity. This lysis might furnish nutrients for the remaining cells as highlighted by genes overexpressed in nucleotide salvage, in amino sugar catabolism and in inorganic ion transports. Several genes involved in DNA/RNA repair and genes encoding proteases and chaperones involved in protein turnover were up-regulated. Furthermore, S. xylosus perceived osmotic and oxidative stresses and responded by up-regulating genes involved in osmoprotectant synthesis and in detoxification. This study provides new insight into the physiology of S. xylosus in biofilm.}, } @article {pmid34834197, year = {2021}, author = {Cataldo Russomando, A and Vogt Sionov, R and Friedman, M and Gati, I and Eliashar, R and Steinberg, D and Gross, M}, title = {Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study.}, journal = {Pharmaceutics}, volume = {13}, number = {11}, pages = {}, pmid = {34834197}, issn = {1999-4923}, abstract = {The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureussubsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureussubsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureussubsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureussubsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.}, } @article {pmid34834158, year = {2021}, author = {Kamli, MR and Malik, MA and Srivastava, V and Sabir, JSM and Mattar, EH and Ahmad, A}, title = {Biogenic ZnO Nanoparticles Synthesized from Origanum vulgare Abrogates Quorum Sensing and Biofilm Formation in Opportunistic Pathogen Chromobacterium violaceum.}, journal = {Pharmaceutics}, volume = {13}, number = {11}, pages = {}, pmid = {34834158}, issn = {1999-4923}, support = {IFPHI-127-130-2020//King Abdulaziz University/ ; }, abstract = {This study presents an inexpensive, eco-friendly, and simple green synthesis of ZnO nanoparticles using Origanum vulgare extract. These nanoparticles are non-hazardous, environmentally friendly, and cheaper than other methods of biosynthesis. Ongoing research determines the role of phytochemicals in the fabrication and biosynthesis of ZnO NPs and their role in antibacterial activity and biomedical applications. Characterizations by fourier transform infrared spectroscopy (FTIR), diffuse reflectance UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) determine the successful biosynthesis of ZnO NPs. Meanwhile, TEM and X-ray diffraction studies approximated the spherical morphology and crystalline nature of biosynthesized ZnO NPs of nano size in the range of 20-30 nm. The global increase in drug resistance necessitates the search for new drugs with different mechanisms of action. Quorum sensing (QS), a cell-to-cell communication, has gained attention as an emerging drug target. It controls numerous biochemical processes in bacteria, which are essential for their survival and pathogenicity. The potential of nanomedicines has also been tested to synthesize new antibiotics to tackle drug resistance. ZnO NPs were explored for their antibacterial, antiquorum sensing, and antibiofilm activities with a bioreporter strain of Chromobacterium violaceum. Susceptibility testing results indicated the potential antibacterial activity of ZnO NPs with a minimum inhibitory concentration (MIC) of 4 µg/mL and minimum bactericidal concentration (MBC) of 16 µg/mL. Antiquorum-sensing assays revealed that these nanoparticles inhibit quorum sensing with minimum antiquorum sensing activity (MQSIC) of 1 µg/mL, without causing any bacterial growth inhibition. In addition, ZnO NPs inhibit biofilm formation at inhibitory and higher concentrations. RT-qPCR results supported the downregulation of the quorum sensing genes when C. violaceum was treated with ZnO NPs. The outcomes of this study are promising with regard to the biofilm and quorum sensing, emphasizing the potential applications of ZnO NPs against bacterial communication and biofilm formation.}, } @article {pmid34834156, year = {2021}, author = {Trizna, E and Baidamshina, D and Gorshkova, A and Drucker, V and Bogachev, M and Tikhonov, A and Kayumov, A}, title = {Improving the Efficacy of Antimicrobials against Biofilm-Embedded Bacteria Using Bovine Hyaluronidase Azoximer (Longidaza[®]).}, journal = {Pharmaceutics}, volume = {13}, number = {11}, pages = {}, pmid = {34834156}, issn = {1999-4923}, support = {МК-3052.2021.1.4//Council for Grants of the President of the Russian Federation/ ; 20-04-00247//Russian Foundation for Basic Research/ ; 0279-2021-0015//The Ministry of Education and Science of the Russian Federation/ ; }, abstract = {While in a biofilm, bacteria are extremely resistant to both antimicrobials and the immune system, leading to the development of chronic infection. Here, we show that bovine hyaluronidase fused with a copolymer of 1,4-ethylenepiperazine N-oxide and (N-carboxymethyl) -1,4-ethylenepiperazinium bromide (Longidaza[®]) destroys both mono- and dual-species biofilms formed by various bacteria. After 4 h of treatment with 750 units of the enzyme, the residual biofilms of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae preserved about 50-70% of their initial mass. Biomasses of dual-species biofilms formed by S. aureus and the four latter species were reduced 1.5-fold after 24 h treatment, while the significant destruction of S. aureus-P. aeruginosa and S. aureus-K. pneumoniae was also observed after 4 h of treatment with Longidaza[®]. Furthermore, when applied in combination, Longidaza[®] increased the efficacy of various antimicrobials against biofilm-embedded bacteria, although with various increase-factor values depending on both the bacterial species and antimicrobials chosen. Taken together, our data indicate that Longidaza[®] destroys the biofilm structure, facilitating the penetration of antimicrobials through the biofilm, and in this way improving their efficacy, lowering the required dose and thus also potentially reducing the associated side effects.}, } @article {pmid34833075, year = {2021}, author = {Glasl, B and Haskell, JB and Aires, T and Serrão, EA and Bourne, DG and Webster, NS and Frade, PR}, title = {Microbial Surface Biofilm Responds to the Growth-Reproduction-Senescence Cycle of the Dominant Coral Reef Macroalgae Sargassum spp.}, journal = {Life (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {34833075}, issn = {2075-1729}, support = {SFRH/BDP/110285/2015//Fundação para a Ciência e Tecnologia/ ; SFRH/BSAB/150485/2019//Fundação para a Ciência e Tecnologia/ ; SFRH/BPD/116774/2016//Fundação para a Ciência e Tecnologia/ ; UID/Multi/04326/2019//Fundação para a Ciência e Tecnologia/ ; Australian Microbiome Initiative//Bioplatforms Australia & Australian Government National Collaborative Research Infrastructure Strategy/ ; PhD Scholarship BG//Advance Queensland/ ; T 1218//FWF Austrian Science Fund/ ; }, abstract = {Macroalgae play an intricate role in microbial-mediated coral reef degradation processes due to the release of dissolved nutrients. However, temporal variabilities of macroalgal surface biofilms and their implication on the wider reef system remain poorly characterized. Here, we study the microbial biofilm of the dominant reef macroalgae Sargassum over a period of one year at an inshore Great Barrier Reef site (Magnetic Island, Australia). Monthly sampling of the Sargassum biofilm links the temporal taxonomic and putative functional metabolic microbiome changes, examined using 16S rRNA gene amplicon and metagenomic sequencing, to the pronounced growth-reproduction-senescence cycle of the host. Overall, the macroalgal biofilm was dominated by the heterotrophic phyla Firmicutes (35% ± 5.9% SD) and Bacteroidetes (12% ± 0.6% SD); their relative abundance ratio shifted significantly along the annual growth-reproduction-senescence cycle of Sargassum. For example, Firmicutes were 1.7 to 3.9 times more abundant during host growth and reproduction cycles than Bacteroidetes. Both phyla varied in their carbohydrate degradation capabilities; hence, temporal fluctuations in the carbohydrate availability are potentially linked to the observed shift. Dominant heterotrophic macroalgal biofilm members, such as Firmicutes and Bacteroidetes, are implicated in exacerbating or ameliorating the release of dissolved nutrients into the ambient environment, though their contribution to microbial-mediated reef degradation processes remains to be determined.}, } @article {pmid34833021, year = {2021}, author = {Buchbender, M and Lugenbühl, A and Fehlhofer, J and Kirschneck, C and Ries, J and Lutz, R and Sticherling, M and Kesting, MR}, title = {Investigation of the Expression of Inflammatory Markers in Oral Biofilm Samples in Patients with Systemic Scleroderma and the Association with Clinical Periodontal Parameters-A Preliminary Study.}, journal = {Life (Basel, Switzerland)}, volume = {11}, number = {11}, pages = {}, pmid = {34833021}, issn = {2075-1729}, abstract = {BACKGROUND: Systemic scleroderma (SSc) has multiple orofacial effects. The aim of this study was to analyze the expression of inflammatory mediators in biofilm samples. It was hypothesized that different expression levels and clinical associations might be drawn.

METHODS: A total of 39 biofilm samples from group 1 = SSc and group 2 = healthy control were examined for the expression levels of interleukin (IL)-2,-6, and -10; matrix metalloprotease (MMP)-9; and surface antigens CD90 and CD34 by quantitative real-time PCR and clinical parameters. Relative quantitative (RQ) gene expression was determined using the ∆∆CT method.

RESULTS: The mean bleeding on probing values (p = 0.006), clinical attachment loss (CAL) (p = 0.009), gingival recession (p = 0.020), limited mouth opening (p = 0.001) and cervical tooth defects (p = 0.011) were significantly higher in group 1. RQ expressions of IL-2 and CD34 were significantly lower, IL-6, MMP-9, and CD90 were significantly higher. There was a significant positive correlation of IL-6/MMP-9 and negative correlation of mouth opening/CAL and IL-6/CAL.

CONCLUSION: Different expression levels of IL-2, IL-6, MMP-9, CD34 and CD90 were detected in biofilm samples from patients with SSc compared to control. An immunological correlation to the clinical parameters of mouth opening and CAL was shown; thus, we conclude that SSc might have an impact on periodontal tissues.}, } @article {pmid34832681, year = {2021}, author = {Park, NH and Lee, SJ and Lee, EB and Birhanu, BT and Park, SC}, title = {Colistin Induces Resistance through Biofilm Formation, via Increased phoQ Expression, in Avian Pathogenic Escherichia coli.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34832681}, issn = {2076-0817}, support = {2019R1A2C2006277//National Research Foundation of Korea/ ; }, abstract = {This study aimed to optimize the colistin-based antibacterial therapy to prevent antimicrobial resistance related to biofilm formation in avian pathogenic Escherichia coli (APEC) in chicken. Of all the bacterial isolates (n = 136), 69 were identified as APEC by polymerase chain reaction (PCR). Through a series of antibiotic susceptibility tests, susceptibility to colistin (<2 μg/mL) was confirmed in all isolates. Hence, a mutant selection window (MSW) was determined to obtain colistin-induced resistant bacteria. The minimum inhibitory concentration (MIC) of colistin against the colistin-induced resistant APEC strains ranged from 8 to 16 μg/mL. To identify the inhibitory activity of colistin against the resistant strains, the mutant prevention concentration (MPC) was investigated for 72 h, and the single and multi-dose colistin activities were determined through the time-kill curve against APEC strains. Bacterial regrowth occurred after 12 h at a double MIC50 concentration (1.00 μg/mL), and regrowth was not inhibited even during multiple exposures. However, upon exposure to 8 μg/mL-a concentration that was close to the MPC-the growth of APEC was inhibited, including in the resistant strains. Additionally, colistin-induced resistant strains showed a slower growth compared with the susceptible ones. Colistin-induced resistant APEC strains did not show colistin resistance gene (mcr-1). However, the expression of higher mgrB and phoQ levels was observed in the resistant strains. Furthermore, these strains showed increased formation of biofilm. Hence, the present study indicated that colistin could induce resistance through the increased formation of biofilm in APEC strains by enhancing the expression of phoQ.}, } @article {pmid34832641, year = {2021}, author = {Albutti, A and Gul, MS and Siddiqui, MF and Maqbool, F and Adnan, F and Ullah, I and Rahman, Z and Qayyum, S and Shah, MA and Salman, M}, title = {Combating Biofilm by Targeting Its Formation and Dispersal Using Gallic Acid against Single and Multispecies Bacteria Causing Dental Plaque.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34832641}, issn = {2076-0817}, support = {NA//Deanship of Scientific Research, Qassim University, Saudi Arabia/ ; }, abstract = {Exploring biological agents to control biofilm is a vital alternative in combating pathogenic bacteria that cause dental plaque. This study was focused on antimicrobial, biofilm formation and biofilm dispersal efficacy of Gallic acid (GA) against bacteria, including Proteus spp., Escherichia coli, Pseudomonas spp., Salmonella spp., Streptococcus mutans, and Staphylococcus aureus and multispecies bacteria. Biofilm was qualitatively and quantitatively assessed by crystal violet assay, florescence microscopy (bacterial biomass (µm[2]), surface coverage (%)) and extracellular polymeric substances (EPS). It was exhibited that GA (1-200 mg/L) can reduce bacterial growth. However, higher concentrations (100-200 mg/L) markedly reduced (86%) bacterial growth and biofilm formation (85.5%), while GA did not exhibit any substantial dispersal effects on pre-formed biofilm. Further, GA (20-200 mg/L) exhibited 93.43% biomass reduction and 88.6% (p < 0.05) EPS (polysaccharide) reduction. Microscopic images were processed with BioImageL software. It was revealed that biomass surface coverage was reduced to 2% at 200 mg/L of GA and that 13,612 (µm[2]) biomass was present for control, while it was reduced to 894 (µm[2]) at 200 mg/L of GA. Thus, this data suggest that GA have antimicrobial and biofilm control potential against single and multispecies bacteria causing dental plaque.}, } @article {pmid34832540, year = {2021}, author = {Paleczny, J and Junka, A and Brożyna, M and Dydak, K and Oleksy-Wawrzyniak, M and Ciecholewska-Juśko, D and Dziedzic, E and Bartoszewicz, M}, title = {The High Impact of Staphylococcus aureus Biofilm Culture Medium on In Vitro Outcomes of Antimicrobial Activity of Wound Antiseptics and Antibiotic.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34832540}, issn = {2076-0817}, support = {STM.D.230.20.127//Wroclaw Medical University/ ; }, abstract = {The staphylococcal biofilm-based infections of wounds still pose a significant therapeutical challenge. Treated improperly, they increase the risk of limb amputation or even death of the patient. The present algorithms of infected wound treatment include, among others, the application of antiseptic substances. In vitro wound biofilm models are applied in order to scrutinize their activity. In the present work, using a spectrum of techniques, we showed how the change of a single variable (medium composition) in the standard in vitro model translates not only to shift in staphylococcal biofilm features but also to the change of efficacy of clinically applied wound antimicrobials such as octenidine, polyhexamethylene biguanide, chlorhexidine, hypochlorite solutions, and locally applied gentamycin. The data presented in this study may be of a pivotal nature, taking into consideration the fact that results of in vitro analyses are frequently used to propagate application of specific antimicrobials in hospitals and ambulatory care units.}, } @article {pmid34832527, year = {2021}, author = {Spałek, J and Daniluk, T and Godlewski, A and Deptuła, P and Wnorowska, U and Ziembicka, D and Cieśluk, M and Fiedoruk, K and Ciborowski, M and Krętowski, A and Góźdź, S and Durnaś, B and Savage, PB and Okła, S and Bucki, R}, title = {Assessment of Ceragenins in Prevention of Damage to Voice Prostheses Caused by Candida Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34832527}, issn = {2076-0817}, support = {024/RID/2018/19//National Science Centre, Poland (UMO-2018/31/B/NZ6/02476 to RB) Medical University of Bialystok (SUB/1/DN/20/001/1122 to MC)/ ; UDA- RPPD.01.01.00-20-001/15-00 dated 26.06.2015//Part of the study was conducted with the use of equipment purchased by the Medical University of Białystok as part of the RPOWP 2007-2013 funding, Priority I, Axis 1.1/ ; }, abstract = {This study aimed to investigate the potential application of ceragenins (CSAs) as new candidacidal agents to prevent biofilm formation on voice prostheses (VPs). The deterioration of the silicone material of VPs is caused by biofilm growth on the device which leads to frequent replacement procedures and sometimes serious complications. A significant proportion of these failures is caused by Candida species. We found that CSAs have significant candidacidal activities in vitro (MIC; MFC; MBIC), and they effectively eradicate species of yeast responsible for VP failure. Additionally, in our in vitro experimental setting, when different Candida species were subjected to CSA-13 and CSA-131 during 25 passages, no tested Candida strain showed the significant development of resistance. Using liquid chromatography-mass spectrometry (LC-MS), we found that VP immersion in an ethanol solution containing CSA-131 results in silicon impregnation with CSA-131 molecules, and in vitro testing revealed that fungal biofilm formation on such VP surfaces was inhibited by embedded ceragenins. Future in vivo studies will validate the use of ceragenin-coated VP for improvement in the life quality and safety of patients after a total laryngectomy.}, } @article {pmid34832519, year = {2021}, author = {Liu, Y and Yang, J and Ji, M and Phillips, J and Wylam, M and Ji, Y}, title = {Identification of cbiO Gene Critical for Biofilm Formation by MRSA CFSa36 Strain Isolated from Pediatric Patient with Cystic Fibrosis.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34832519}, issn = {2076-0817}, support = {MIN-63-113//TThe College of Veterinary Medicine at the University of Minnesota USDA Agricultural General Research fund/ ; }, abstract = {The colonization of Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has a detrimental effect on the respiratory care of pediatric patients with cystic fibrosis (CF). In addition to being resistant to multiple antibiotics, S. aureus also has the ability to form biofilms, which makes the infection more difficult to treat and eradicate. In this study, we examined the ability of S. aureus strains isolated from pediatric patients with CF to form biofilms. We screened a transposon mutant library of MRSA and identified a putative cobalt transporter ATP binding domain (cbiO) that is required for biofilm formation. We discovered that deleting cbiO creating a cbiO null mutant in CFSa36 (an MRSA strain isolated from a patient with cystic fibrosis) significantly hinders the ability of CFSa36 to form biofilm. The complementation of cbiO restored the ability of the cbiO deletion mutant to generate biofilm. Interestingly, we revealed that incorporating extra copper ions to the chemically defined medium (CDM) complemented the function of cbiO for biofilm formation in a dose-dependent manner, while the addition of extra iron ions in CDM enhanced the effect of cbiO null mutation on biofilm formation. In addition, neither the addition of certain extra amounts of copper ions nor iron ions in CDM had an impact on bacterial growth. Taken together, our findings suggest that cbiO mediates biofilm formation by affecting the transportation of copper ions in the MRSA CFSa36 strain. This study provides new insights into the molecular basis of biofilm formation by S. aureus.}, } @article {pmid34830415, year = {2021}, author = {Kim, D and Kim, KY}, title = {Adenophora triphylla var. japonica Inhibits Candida Biofilm Formation, Increases Susceptibility to Antifungal Agents and Reduces Infection.}, journal = {International journal of molecular sciences}, volume = {22}, number = {22}, pages = {}, pmid = {34830415}, issn = {1422-0067}, support = {GRRC-KyungHee2020(B04)//Kyung Hee University/ ; }, mesh = {Antifungal Agents/pharmacology ; Biofilms/drug effects ; Campanulaceae/*chemistry ; Candida albicans/*drug effects/pathogenicity ; Cell Aggregation/drug effects ; Humans ; Hyphae/drug effects ; Mycoses/*drug therapy/microbiology ; Plant Extracts/chemistry/*pharmacology ; }, abstract = {(1) Background: Candida is the most common cause of fungal infections worldwide, but due to the limited option of antifungal therapies, alternative strategies are required. (2) Methods: Adenophora triphylla var. japonica extract was used for the biofilm formation assay using RPMI1640. The combinatorial antifungal assay, the dimorphic transition assay, and the adherence assay were done to see the influence of inhibition of biofilm formation. qRT-PCR analysis were performed to check the gene expression. (3) Results: Adenophora triphylla var. japonica extract inhibited the Candida biofilm formation. Treatment of extract increased the antifungal susceptibility of miconazole from a 37% reduction in fungal growth to 99.05%, and also dose-dependently reduced the dimorphic transition of Candida and the attachment of Candida to HaCaT cells. The extract blocked the expression of hyphal-related genes, extracellular matrix genes, Ras1-cAMP-PKA pathway genes, Cph2-Tec1 pathway gene, and MAP kinase pathway gene. (4) Conclusions: In this study, the treatment of Adenophora triphylla var. japonica extract showed inhibition of fungal biofilm formation, activation of antifungal susceptibility, and reduction of infection. These results suggest that fungal biofilm formation is a good target for the development of antifungal adjuvants, and Adenophora triphylla var. japonica extract should be a good candidate for biofilm-associated fungal infections.}, } @article {pmid34829908, year = {2021}, author = {Wong, PC and Wang, RY and Lu, LS and Wang, WR and Jang, JS and Wu, JL and Su, TY and Chang, LH}, title = {Two-Step Approach Using Degradable Magnesium to Inhibit Surface Biofilm and Subsequently Kill Planktonic Bacteria.}, journal = {Biomedicines}, volume = {9}, number = {11}, pages = {}, pmid = {34829908}, issn = {2227-9059}, support = {MOST 109-2314-B-038-149//Ministry of Science and technology of Taiwan/ ; MOST 110-2221-E-155 -043 -MY3//Ministry of Science and technology of Taiwan/ ; MOST 109-2221-E-155-035-MY3//Ministry of Science and technology of Taiwan/ ; }, abstract = {Bacterial infection remains a great risk in medical implantation surgery. In this paper, we found that degradable metals may be a feasible alternative option of antibacterial implantation materials. It is known that the spalling mechanism of magnesium (Mg) during degradation leads to Mg ions-induced alkaline environment, which is harmful to planktonic bacteria. In this study, we showed that alkaline pH environment is almost harmless to those adhesive bacteria protected in well-formed biofilms. Moreover, experimental results demonstrated that the biofilm formed in the place where Mg spalls are destroyed, releasing the covered bacteria to be planktonic in the alkaline environment. As a result, the colonization of biofilms continues to shrink during the degradation of Mg. It implies that if degradable metal is employed as implantation material, even if bacterial infection occurs, it may be possibly cured without second surgery.}, } @article {pmid34829129, year = {2021}, author = {Muro-Fraguas, I and Fernández-Gómez, P and Múgica-Vidal, R and Sainz-García, A and Sainz-García, E and Oliveira, M and González-Raurich, M and López, M and Rojo-Bezares, B and López, M and Alba-Elías, F}, title = {Durability Assessment of a Plasma-Polymerized Coating with Anti-Biofilm Activity against L. monocytogenes Subjected to Repeated Sanitization.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34829129}, issn = {2304-8158}, support = {PID2020-113658RB-C2//Ministerio de Ciencia e Innovación/ ; }, abstract = {Biofilm formation on food-contact surfaces is a matter of major concern causing food safety and spoilage issues to this sector. The aim of this study was to assess the durability of the anti-biofilm capacity of a plasma-polymerized coating composed of a base coating of (3-aminopropyl)triethoxysilane (APTES) and a functional coating of acrylic acid (AcAc). Coated and uncoated AISI 316 stainless steel (SS) plates were subjected to five sanitization cycles with sodium hypochlorite (0.05%) and peracetic acid (0.5%). The effectiveness of the coating for the inhibition of multi-strain Listeria monocytogenes biofilm formation was confirmed using a three-strain cocktail, which was grown on the SS plates at 12 °C for 6 days. Compared to the uncoated SS, relative biofilm productions of 14.6% on the non-sanitized coating, 27.9% on the coating after sanitization with sodium hypochlorite, and 82.3% on the coating after sanitization with peracetic acid were obtained. Morphological and physicochemical characterization of the coatings suggested that the greater anti-biofilm effectiveness after sanitization with sodium hypochlorite was due to the high pH of this solution, which caused a deprotonation of the carboxylic acid groups of the functional coating. This fact conferred it a strong hydrophilicity and negatively charged its surface, which was favorable for preventing bacterial attachment and biofilm formation.}, } @article {pmid34828898, year = {2021}, author = {Wen, QH and Wang, R and Zhao, SQ and Chen, BR and Zeng, XA}, title = {Inhibition of Biofilm Formation of Foodborne Staphylococcus aureus by the Citrus Flavonoid Naringenin.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34828898}, issn = {2304-8158}, support = {21576099//National Natural Science Foundation of China/ ; 2017YFD0400502//National "Thirteenth Five" Key Research Project/ ; }, abstract = {Taking into consideration the importance of biofilms in food deterioration and the potential risks of antiseptic compounds, antimicrobial agents that naturally occurring are a more acceptable choice for preventing biofilm formation and in attempts to improve antibacterial effects and efficacy. Citrus flavonoids possess a variety of biological activities, including antimicrobial properties. Therefore, the anti-biofilm formation properties of the citrus flavonoid naringenin on the Staphylococcus aureus ATCC 6538 (S. aureus) were investigated using subminimum inhibitory concentrations (sub-MICs) of 5~60 mg/L. The results were confirmed using laser and scanning electron microscopy techniques, which revealed that the thick coating of S. aureus biofilms became thinner and finally separated into individual colonies when exposed to naringenin. The decreased biofilm formation of S. aureus cells may be due to a decrease in cell surface hydrophobicity and exopolysaccharide production, which is involved in the adherence or maturation of biofilms. Moreover, transcriptional results show that there was a downregulation in the expression of biofilm-related genes and alternative sigma factor sigB induced by naringenin. This work provides insight into the anti-biofilm mechanism of naringenin in S. aureus and suggests the possibility of naringenin being used in the industrial food industry for the prevention of biofilm formation.}, } @article {pmid34827779, year = {2021}, author = {Gogoi-Tiwari, J and Dorji, D and Tiwari, HK and Shirolkar, G and Aleri, JW and Mukkur, T}, title = {Phenotypic PIA-Dependent Biofilm Production by Clinical Non-Typeable Staphylococcus aureus Is Not Associated with the Intensity of Inflammation in Mammary Gland: A Pilot Study Using Mouse Mastitis Model.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {11}, pages = {}, pmid = {34827779}, issn = {2076-2615}, support = {BF040038//Australia India Strategic Research Fund/ ; BF040038//Department of Industry, Innovation, Science, Research and Tertiary Education, Australian Government/ ; }, abstract = {Non-typeable (NT) Staphylococcus aureus strains are associated with chronic bovine mastitis. This study investigates the impact of biofilm formation by clinical NT S. aureus on cytokine production and mammary tissue damage by using a mouse mastitis model. Mice infected with two different NT S. aureus strains with strong and weak biofilm forming potential demonstrated identical clinical symptoms (moderate), minimal inflammatory infiltrates, and tissue damage (level 1 histopathological changes) in the mammary glands. However, the S. aureus load in the mammary glands of mice and the level of pro-inflammatory cytokines (IL-1β, IL-6, IL-12, IL-17 and IFN-γ) in serum were significantly higher (p ≤ 0.05) in those infected with the strong biofilm forming NT S. aureus strain. The level of IL-6 in sera samples of these mice was extremely high (15,479.9 ± 532 Pg/mL). Furthermore, these mice died in 24h of post infection compared to 30 h in the weak biofilm forming NT S. aureus infected group. The study demonstrates no association between the strength of PIA (polysaccharide intercellular adhesion)-dependent biofilm production by clinical NT S. aureus and mammary gland pathology in a mouse mastitis model. However, the role of biofilm in the virulence of S. aureus advancing the time of mortality in mice warrants further investigation.}, } @article {pmid34827725, year = {2021}, author = {Maťátková, O and Kolouchová, I and Lokočová, K and Michailidu, J and Jaroš, P and Kulišová, M and Řezanka, T and Masák, J}, title = {Rhamnolipids as a Tool for Eradication of Trichosporon cutaneum Biofilm.}, journal = {Biomolecules}, volume = {11}, number = {11}, pages = {}, pmid = {34827725}, issn = {2218-273X}, mesh = {*Basidiomycota ; Biofilms ; *Glycolipids ; }, abstract = {Microbial biofilms formed by pathogenic and antibiotic-resistant microorganisms represent a serious threat for public health in medicine and many industrial branches. Biofilms are involved in many persistent and chronic infections, the biofouling of water and food contamination. Therefore, current research is involved in the development of new treatment strategies. Biofilm is a complex system, and thus all aspects of the measurement and monitoring of its growth and eradication in various conditions, including static and dynamic flow, are issues of great importance. The antibiofilm character of rhamnolipid mixtures produced by four Pseudomonas aeruginosa strains was studied under different conditions. For this purpose, the biofilm of opportunistic pathogen Trichosporon cutaneum was used and treated under static conditions (microscope glass coverslip in a Petri dish) and under dynamic conditions (a single-channel flow cell). The results show that the biological activity of rhamnolipids depends both on their properties and on the conditions of the biofilm formation. Therefore, this aspect must be taken into account when planning the experimental or application design.}, } @article {pmid34827361, year = {2021}, author = {Mangieri, N and Foschino, R and Picozzi, C}, title = {Application of Bacteriophages on Shiga Toxin-Producing Escherichia coli (STEC) Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827361}, issn = {2079-6382}, abstract = {Shiga toxin-producing Escherichia coli are pathogenic bacteria able to form biofilms both on abiotic surfaces and on food, thus increasing risks for food consumers. Moreover, biofilms are difficult to remove and more resistant to antimicrobial agents compared to planktonic cells. Bacteriophages, natural predators of bacteria, can be used as an alternative to prevent biofilm formation or to remove pre-formed biofilm. In this work, four STEC able to produce biofilm were selected among 31 different strains and tested against single bacteriophages and two-phage cocktails. Results showed that our phages were able to reduce biofilm formation by 43.46% both when used as single phage preparation and as a cocktail formulation. Since one of the two cocktails had a slightly better performance, it was used to remove pre-existing biofilms. In this case, the phages were unable to destroy the biofilms and reduce the number of bacterial cells. Our data confirm that preventing biofilm formation in a food plant is better than trying to remove a preformed biofilm and the continuous presence of bacteriophages in the process environment could reduce the number of bacteria able to form biofilms and therefore improve the food safety.}, } @article {pmid34827318, year = {2021}, author = {Elsayed, R and El-Awady, A and Cutler, C and Kurago, Z and Elashiry, M and Sun, C and Bloomquist, R and Meghil, MM and Elsalanty, ME}, title = {Matrix-Bound Zolzoledronate Enhances the Biofilm Colonization of Hydroxyapatite: Effects on Osteonecrosis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827318}, issn = {2079-6382}, support = {2R15DE025134-02/DE/NIDCR NIH HHS/United States ; R01DE02946801/DE/NIDCR NIH HHS/United States ; S10OD025177//National Institute of Health/ ; 001//Carlos and Marguerite Mason Trust/ ; }, abstract = {(1) Background: The aim of this study was to test whether matrix-bound zoledronate (zol) molecules enhanced the oral biofilm colonization of a mineralized matrix, rendering the alveolar bone more susceptible to medication-related osteonecrosis of the jaw (MRONJ) following invasive dental procedures. (2) Methods: We tested the effect of matrix-bound zol on the growth and attachment of Porphyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn) and Actinomyces israelii (Ai), and whether the nitrogen-containing component of zol contributed to such effect. The role of oral bacteria in the induction of osteonecrosis was then tested using an extra-oral bone defect model. (3) Results: The attachment of biofilm to hydroxyapatite discs increased when the discs were pre-treated with zol. Bacterial proliferation was not affected. Matrix-bound zol was more potent than non-nitrogen-containing etidronate in enhancing the colonization. Stimulation was dampened by pre-treating the bacteria with histidine. The delivery of oral biofilm to a tibial defect caused osteonecrosis in zol-treated rats. (4) Conclusions: We conclude that matrix-bound zol enhances the oral biofilm colonization of hydroxyapatite. This enhancement depended on the presence of the nitrogen-containing group. The oral biofilm rendered the extra-oral bone susceptible to medication-related osteonecrosis, suggesting that it has an important role in the induction of MRONJ.}, } @article {pmid34827315, year = {2021}, author = {Simonetti, O and Rizzetto, G and Radi, G and Molinelli, E and Cirioni, O and Giacometti, A and Offidani, A}, title = {New Perspectives on Old and New Therapies of Staphylococcal Skin Infections: The Role of Biofilm Targeting in Wound Healing.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827315}, issn = {2079-6382}, abstract = {Among the most common complications of both chronic wound and surgical sites are staphylococcal skin infections, which slow down the wound healing process due to various virulence factors, including the ability to produce biofilms. Furthermore, staphylococcal skin infections are often caused by methicillin-resistant Staphylococcus aureus (MRSA) and become a therapeutic challenge. The aim of this narrative review is to collect the latest evidence on old and new anti-staphylococcal therapies, assessing their anti-biofilm properties and their effect on skin wound healing. We considered antibiotics, quorum sensing inhibitors, antimicrobial peptides, topical dressings, and antimicrobial photo-dynamic therapy. According to our review of the literature, targeting of biofilm is an important therapeutic choice in acute and chronic infected skin wounds both to overcome antibiotic resistance and to achieve better wound healing.}, } @article {pmid34827310, year = {2021}, author = {Adnan, M and Siddiqui, AJ and Hamadou, WS and Ashraf, SA and Hassan, MI and Snoussi, M and Badraoui, R and Jamal, A and Bardakci, F and Awadelkareem, AM and Sachidanandan, M and Patel, M}, title = {Functional and Structural Characterization of Pediococcus pentosaceus-Derived Biosurfactant and Its Biomedical Potential against Bacterial Adhesion, Quorum Sensing, and Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827310}, issn = {2079-6382}, support = {RG-20094//University of Hail/ ; }, abstract = {Biosurfactants are surface-active molecules of microbial origin and alternatives to synthetic surfactants with various applications. Due to their environmental-friendliness, biocompatibility, biodegradability, effectiveness to work under various environmental conditions, and non-toxic nature, they have been recently recognized as potential agents with therapeutic and commercial importance. The biosurfactant produced by various probiotic lactic acid bacteria (LAB) has enormous applications in different fields. Thus, in vitro assessment of biofilm development prevention or disruption by natural biosurfactants derived from probiotic LAB is a plausible approach that can lead to the discovery of novel antimicrobials. Primarily, this study aims to isolate, screen, and characterize the functional and biomedical potential of biosurfactant synthesized by probiotic LAB Pediococcus pentosaceus (P. pentosaceus). Characterization consists of the assessment of critical micelle concentration (CMC), reduction in surface tension, and emulsification index (% EI24). Evaluation of antibacterial, antibiofilm, anti-QS, and anti-adhesive activities of cell-bound biosurfactants were carried out against different human pathogenic bacteria (B. subtilis, P. aeruginosa, S. aureus, and E. coli). Moreover, bacterial cell damage, viability of cells within the biofilm, and exopolysaccharide (EPS) production were also evaluated. As a result, P. pentosaceus was found to produce 4.75 ± 0.17 g/L biosurfactant, which displayed a CMC of 2.4 ± 0.68 g/L and reduced the surface tension from 71.11 ± 1.12 mN/m to 38.18 ± 0.58 mN/m. P. pentosaceus cells bound to the crude biosurfactant were found to be effective against all tested bacterial pathogens. It exhibited an anti-adhesion ability and impeded the architecture of the biofilm matrix by affecting the viability and integrity of bacterial cells within biofilms and reducing the total EPS content. Furthermore, the crude biosurfactant derived from P. pentosaceus was structurally characterized as a lipoprotein by GC-MS analysis, which confirms the presence of lipids and proteins. Thus, our findings represent the potent anti-adhesion and antibiofilm potential of P. pentosaceus crude biosurfactant for the first time, which may be explored further as an alternative to antibiotics or chemically synthesized toxic antibiofilm agents.}, } @article {pmid34827297, year = {2021}, author = {Alfarrayeh, I and Pollák, E and Czéh, Á and Vida, A and Das, S and Papp, G}, title = {Antifungal and Anti-Biofilm Effects of Caffeic Acid Phenethyl Ester on Different Candida Species.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827297}, issn = {2079-6382}, abstract = {This study investigated the effect of CAPE on planktonic growth, biofilm-forming abilities, mature biofilms, and cell death of C. albicans, C. tropicalis, C. glabrata, and C. parapsilosis strains. Our results showed a strain- and dose-dependent effect of CAPE on Candida, and the MIC values were between 12.5 and 100 µg/mL. Similarly, the MBIC values of CAPE ranging between 50 and 100 µg/mL highlighted the inhibition of the biofilm-forming abilities in a dose-dependent manner, as well. However, CAPE showed a weak to moderate biofilm eradication ability (19-49%) on different Candida strains mature biofilms. Both caspase-dependent and caspase-independent apoptosis after CAPE treatment were observed in certain tested Candida strains. Our study has displayed typical apoptotic hallmarks of CAPE-induced chromatin margination, nuclear blebs, nuclear condensation, plasma membrane detachment, enlarged lysosomes, cytoplasm fragmentation, cell wall distortion, whole-cell shrinkage, and necrosis. In conclusion, CAPE has a concentration and strain-dependent inhibitory activity on viability, biofilm formation ability, and cell death response in the different Candida species.}, } @article {pmid34827287, year = {2021}, author = {Patel, N and Curtis, JC and Plotkin, BJ}, title = {Insulin Regulation of Escherichia coli Abiotic Biofilm Formation: Effect of Nutrients and Growth Conditions.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827287}, issn = {2079-6382}, abstract = {Escherichia coli plays an important role in biofilm formation across a wide array of disease and ecological settings. Insulin can function as an adjuvant in the regulation of biofilm levels. The modulation of insulin-regulated biofilm formation by environmental conditions has not been previously described. In the present study, the effects that various environmental growth conditions and nutrients have on insulin-modulated levels of biofilm production were measured. Micropipette tips were incubated with E. coli ATCC[®] 25922™ in a Mueller Hinton broth (MH), or a yeast nitrogen base with 1% peptone (YNBP), which was supplemented with glucose, lactose, galactose and/or insulin (Humulin[®]-R). The incubation conditions included a shaking or static culture, at 23 °C or 37 °C. After incubation, the biofilm production was calculated per CFU. At 23 °C, the presence of insulin increased biofilm formation. The amount of biofilm formation was highest in glucose > galactose >> lactose, while the biofilm levels decreased in shaking cultures, except for galactose (3-fold increase; 0.1% galactose and 20 μU insulin). At 37 °C, regardless of condition, there was more biofilm formation/CFU under static conditions in YNBP than in MH, except for the MH containing galactose. E. coli biofilm formation is influenced by aeration, temperature, and insulin concentration in combination with the available sugars.}, } @article {pmid34827276, year = {2021}, author = {Thambirajoo, M and Maarof, M and Lokanathan, Y and Katas, H and Ghazalli, NF and Tabata, Y and Fauzi, MB}, title = {Potential of Nanoparticles Integrated with Antibacterial Properties in Preventing Biofilm and Antibiotic Resistance.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827276}, issn = {2079-6382}, support = {TRGS/1/2019/UKM/02/1/3//Ministry of Higher Education Malaysia via Transdisciplinary Research Grant Scheme/ ; }, abstract = {Nanotechnology has become an emerging technology in the medical field and is widely applicable for various clinical applications. The potential use of nanoparticles as antimicrobial agents is greatly explored and taken into consideration as alternative methods to overcome the challenges faced by healthcare workers and patients in preventing infections caused by pathogenic microorganisms. Among microorganisms, bacterial infections remain a major hurdle and are responsible for high morbidity and mortality globally, especially involving those with medical conditions and elderly populations. Over time, these groups are more vulnerable to developing resistance to antibiotics, as bacterial biofilms are difficult to destroy or eliminate via antibiotics; thus, treatment becomes unsuccessful or ineffective. Mostly, bacterial biofilms and other microbes can be found on medical devices and wounds where they disperse their contents which cause infections. To inhibit biofilm formations and overcome antibiotic resistance, antimicrobial-loaded nanoparticles alone or combined with other substances could enhance the bactericidal activity of nanomaterials. This includes killing the pathogens effectively without harming other cells or causing any adverse effects to living cells. This review summarises the mechanisms of actions employed by the different types of nanoparticles which counteract infectious agents in reducing biofilm formation and improve antibiotic therapy for clinical usage.}, } @article {pmid34827255, year = {2021}, author = {Abusrewil, S and Brown, JL and Delaney, C and Butcher, MC and Tiba, M and Scott, JA and Ramage, G and McLean, W}, title = {Chitosan Enhances the Anti-Biofilm Activity of Biodentine against an Interkingdom Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {11}, pages = {}, pmid = {34827255}, issn = {2079-6382}, support = {BB/P504567/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/V509541/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Endodontic infection is a biofilm disease that is difficult to irradicate with current treatment protocols, and as such, persistent micro-organisms may lead to ongoing or recurrent disease. The potential for the use of enhanced filling materials to modify biofilm regrowth is a promising strategy. This current study aimed to evaluate the anti-biofilm efficacy of calcium silicate cements modified with chitosan. The development of mono-species and multi-species biofilms on ProRoot MTA, Biodentine and bovine dentine discs were explored using quantitative microbiology analysis. The effect on regrowth of biofilms was assessed following the addition of chitosan to each cement. In comparison to a dentine substrate, both materials did not show the ability to inhibit biofilm regrowth. Biodentine incorporated with chitosan displayed a dose-dependent reduction in multi-species biofilm regrowth, unlike MTA. Notably, interkingdom biofilms were shown to enhance bacterial tolerance in the presence of chitosan. This study demonstrates the potential to enhance the antimicrobial properties of Biodentine. The findings highlight the need for appropriate model systems when exploring antimicrobial properties of materials in vitro so that interspecies and interkingdom interactions that modify tolerance are not overlooked while still supporting the development of innovative materials.}, } @article {pmid34826739, year = {2022}, author = {Zhang, J and Peng, Y and Li, X and Du, R}, title = {Feasibility of partial-denitrification/ anammox for pharmaceutical wastewater treatment in a hybrid biofilm reactor.}, journal = {Water research}, volume = {208}, number = {}, pages = {117856}, doi = {10.1016/j.watres.2021.117856}, pmid = {34826739}, issn = {1879-2448}, mesh = {Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Denitrification ; Feasibility Studies ; Nitrogen/analysis ; Oxidation-Reduction ; *Pharmaceutical Preparations ; Sewage ; Wastewater ; *Water Purification ; }, abstract = {Biological nitrogen removal from pharmaceutical wastewater has drawn increasing attention due to biotoxicity and inhibition. In this study, for the first time, a novel approach integrating partial-denitrification with anaerobic ammonia oxidation (PD/A) in a sequencing biofilm batch reactor (SBBR) was proposed and demonstrated to be efficient to treat the bismuth nitrate and bismuth potassium citrate manufacturing wastewater, containing ammonia (NH4[+]-N) and nitrate (NO3[-]-N) of 6300±50 mg L [-] [1] and 15,300±50 mg L [-] [1]. The maximum anammox activity was found at the shock effect of influent total nitrogen (TN) of 100 mg L [-] [1] with NO3[-]-N/NH4[+]-N of 1.0. Long-term operation demonstrated that the PD/A biofilm was developed rapidly after 30 days using synthetic influent, with TN removal efficiency increasing from 40.9% to 80.8%. Significantly, the key bacteria for PD/A had high tolerance and adapted rapidly to pharmaceutical wastewater, achieving a relatively stable TN removal efficiency of 81.2% with influent NH4[+]-N and NO3[-]-N was 77.9 ± 2.6 and 104.1 ± 4.4 mg L [-] [1] at a relatively low COD/NO3[-]-N of 2.6. Anammox pathway contributed to TN removal reached 83.6%. Significant increase of loosely-bound extracellular polymeric substances was obtained with increasing protein of 3-turn helices structure as response to the inhibitory condition. High-throughput sequencing analysis revealed that the functional genus Thauera was highly enriched in both biofilms (9.5%→43.6%) and suspended biomass (15.5%→57.5%), which played a key role in high NO2[-]-N accumulation. While the anammox bacteria decreasing from 7.8% to 1.6% in biofilm, and from 1.8% decreased to 0.1% in the suspended sludge. Overall, this study provides a new method of high-strength pharmaceutical wastewater treatment with low energy consumption and operation cost, as well as a satisfactory efficiency.}, } @article {pmid34826143, year = {2022}, author = {An, SQ and Hull, R and Metris, A and Barrett, P and Webb, JS and Stoodley, P}, title = {An in vitro biofilm model system to facilitate study of microbial communities of the human oral cavity.}, journal = {Letters in applied microbiology}, volume = {74}, number = {3}, pages = {302-310}, doi = {10.1111/lam.13618}, pmid = {34826143}, issn = {1472-765X}, support = {BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; NBIC 01POC18035/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms ; Humans ; *Microbiota ; Mouth ; RNA, Ribosomal, 16S/genetics ; Reproducibility of Results ; }, abstract = {The human oral cavity is host to a diverse microbiota. Much of what is known about the behaviour of oral microbes derives from studies of individual or several cultivated species, situations which do not totally reflect the function of organisms within more complex microbiota or multispecies biofilms. The number of validated models that allow examination of the role that biofilms play during oral cavity colonization is also limited. The CDC biofilm reactor is a standard method that has been deployed to study interactions between members of human microbiotas allowing studies to be completed during an extended period under conditions where nutrient availability, and washout of waste products are controlled. The objective of this work was to develop a robust in vitro biofilm-model system from a pooled saliva inoculum to study the development, reproducibility and stability of the oral microbiota. By employing deep sequencing of the variable regions of the 16S rRNA gene, we found that the CDC biofilm reactor could be used to efficiently cultivate microbiota containing all six major phyla previously identified as the core saliva microbiota. After an acclimatisation period, communities in each reactor stabilised. Replicate reactors were predominately populated by a shared core microbiota; variation between replicate reactors was primarily driven by shifts in abundance of shared operational taxonomic units. We conclude that the CDC biofilm reactor can be used to cultivate communities that replicate key features of the human oral cavity and is a useful tool to facilitate studies of the dynamics of these communities.}, } @article {pmid34825290, year = {2021}, author = {Rezaei, Z and Khanzadi, S and Salari, A}, title = {Biofilm formation and antagonistic activity of Lacticaseibacillus rhamnosus (PTCC1712) and Lactiplantibacillus plantarum (PTCC1745).}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {156}, pmid = {34825290}, issn = {2191-0855}, support = {Ferdowsi University of Mashhad//Ferdowsi University of Mashhad/ ; }, abstract = {Currently, the health benefits of probiotic bacteria are well known, and this has taken up a great deal of space in food science and health, both research and operational. On the other hand, anti-biofilm properties on food pathogens in the food and pharmaceutical industries have created an attractive challenge. This study aimed to describe the inhibitory activity of cell-free supernatants (CFS), planktonic cells, and biofilm form of lactobacilus strains (L. rhamnosus and L. plantarum) against food pathogens such as Pseudomonas aeruginosa and Listeria monocytogenes. Anti-bacterial activities of the CFS of lactobacillus strains were assessed by the microplate method and via violet staining. Evaluation of the antagonistic activity of planktonic cells and biofilm of LAB were performed by the spread plate method. The results showed the incubation time of 48 h was the best time to produce biofilm. Although the planktonic states reduce the pathogens bacterial about 1 -1.5 log, but in biofilm forms, decreased L. monocytogenes about 4.5 log compared to the control, and in the case of P. aeruginosa, a growth reduction of about 2.13 log was observed. Furthermore, biofilm formation of L. monocytogenes in the presence of L. rhamnosus cell-free supernatant was more weakly than L. plantarum CFS, but their CFS effect on reducing the bacterial population of P. aeruginosa was the same. According to the study, biofilm produced by probiotic strains can be considered a new approach for biological control. Also, cell-free supernatant can be used as postbiotic in the food and pharmaceutical industries.}, } @article {pmid34825176, year = {2021}, author = {Redman, WK and Welch, GS and Williams, AC and Damron, AJ and Northcut, WO and Rumbaugh, KP}, title = {Efficacy and safety of biofilm dispersal by glycoside hydrolases in wounds.}, journal = {Biofilm}, volume = {3}, number = {}, pages = {100061}, pmid = {34825176}, issn = {2590-2075}, support = {R21 AI137462/AI/NIAID NIH HHS/United States ; }, abstract = {Novel anti-biofilm and dispersal agents are currently being investigated in an attempt to combat biofilm-associated wound infections. Glycoside hydrolases (GHs) are enzymes that hydrolyze the glycosidic bonds between sugars, such as those found within the exopolysaccharides of the biofilm matrix. Previous studies have shown that GHs can weaken the matrix, inducing bacterial dispersal, and improving antibiotic clearance. Yet, the number of GH enzymes that have been examined for potential therapeutic effects is limited. In this study, we screened sixteen GHs for their ability to disperse mono-microbial and polymicrobial biofilms grown in different environments. Six GHs, α-amylase (source: A. oryzae), alginate lyase (source: various algae), pectinase (source: Rhizopus sp.), amyloglucosidase (source: A. niger), inulinase (source: A. niger), and xylanase (source: A. oryzae), exhibited the highest dispersal efficacy in vitro. Two GHs, α-amylase (source: Bacillus sp.) and cellulase (source: A. niger), used in conjunction with meropenem demonstrated infection clearing ability in a mouse wound model. GHs were also effective in improving antibiotic clearance in diabetic mice. To examine their safety, we screened the GHs for toxicity in cell culture. Overall, there was an inverse relationship between enzyme exposure time and cellular toxicity, with twelve out of sixteen GHs demonstrating some level of toxicity in cell culture. However, only one GH exhibited harmful effects in mice. These results further support the ability of GHs to improve antibiotic clearance of biofilm-associated infections and help lay a foundation for establishing GHs as therapeutic agents for chronic wound infections.}, } @article {pmid34824750, year = {2021}, author = {Nemati Shizari, L and Mohammadpour Dounighi, N and Bayat, M and Mosavari, N}, title = {A New Amphotericin B-loaded Trimethyl Chitosan Nanoparticles as a Drug Delivery System and Antifungal Activity on Candida albicans Biofilm.}, journal = {Archives of Razi Institute}, volume = {76}, number = {3}, pages = {571-586}, pmid = {34824750}, issn = {2008-9872}, mesh = {Amphotericin B ; Antifungal Agents ; Biofilms ; Candida albicans ; *Chitosan ; Drug Carriers ; Drug Delivery Systems ; *Nanoparticles ; }, abstract = {Amphotericin B (AmB) is an effective antifungal agent; however, the application of AmB is associated with a number of drawbacks. Application of nanoparticles (NPs) is known to improve the efficiency of drug delivery to the target tissues, compared to the traditional methods. In this study, a novel method of NPs preparation was developed. The trimethyl chitosan (TMC) was synthesized using low molecular weight chitosan and was used for the preparation of TMC-NPs through ionic gelation method. Afterward, AmB-loaded TMC-NPs (TMC-NPs/AmB) were prepared and their drug delivery potential was testes. The TMC-NPs and TMC-NPs/AmB were characterized for their structure, particle size, Zeta potential, polydispersity index, morphology, loading efficiency, loading capacity, in vitro release profile, release kinetic, and entrapped AmB potency. The cytotoxicity and antifungal activity of TMC-NPs/AmB against Candida albicans biofilm were evaluated. The quaternization of TMC was estimated to be 36.4%. The mean particle size of TMC-NPs and TMC NPs/AmB were 210±15 and 365±10 nm, respectively, with a PDI of 0.30 and 0.4, ZP of +34±0.5 and +28±0.5 mV, respectively. Electron microscopy analysis indicated uniform spherical shapes with smooth surfaces. The TMC-NPs/AmB indicated LE of 76% and LC of 74.04 % with a potency of 110%. The release profile of TMC-NPs/AmB was best explained by the Higuchi model. The initial release after 10 h was obtained at 38%, and the rates of release after 36 and 84 h were determined at 67% and 76% respectively, which was significantly different (P<0.05) from previous time points. The minimum inhibitory concentration (MIC) (50%) of NPs/AmB and AmB were 0.65 and 1.75 μg/mL, and the MIC 80% were determined at 1.95 and 7.75 μg/mL, respectively, demonstrating a significant improvement in antifungal activity. The half-maximal inhibitory concentration for TMC-NPs/AmB and AmB were estimated at 86 and 105 μg/mL, respectively, indicating a significant reduction in cytotoxicity and the adverse effect. This study could successfully introduce a practical method to synthesize TMC-NPs. The encapsulation process was efficient and significantly improved the antifungal activity of AmB. The developed method can be applied to improve the feasibility of oral delivery while reducing the adverse effects associated with traditional methods.}, } @article {pmid34824531, year = {2021}, author = {Mao, M and Zhang, W and Huang, Z and Huang, J and Wang, J and Li, W and Gu, S}, title = {Graphene Oxide-Copper Nanocomposites Suppress Cariogenic Streptococcus mutans Biofilm Formation.}, journal = {International journal of nanomedicine}, volume = {16}, number = {}, pages = {7727-7739}, pmid = {34824531}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cariostatic Agents ; Copper/pharmacology ; *Dental Caries ; *Graphite ; Humans ; *Nanocomposites ; Streptococcus mutans ; }, abstract = {INTRODUCTION: Dental caries is a biofilm-dependent disease that largely relies on the ability of Streptococcus mutans to synthesize exopolysaccharide matrix. Graphene oxide-based metal nanomaterials, as the derivatives of graphene, are potent agents against pathogens by their impressive antibacterial and anti-biofilm biofunctions. Previously, we fabricated the novel graphene oxide-copper nanocomposites (GO-Cu), maintaining a long-term release of copper nanoparticles. Here, the biofunctionalization of GO-Cu nanocomposites against cariogenic S. mutans is investigated.

METHODS: Growth curve observation and colony forming units counting were applied to detect the antibacterial effect of GO-Cu nanocomposites on S. mutans. Scanning electron microscopy and the crystal violet assay were used to detect nanocomposite effects on biofilm forming ability. The production and distribution of exopolysaccharides within biofilm was analyzed and the expression of genes required for biofilm formation was explored. Moreover, the regulatory landscape of GO-Cu nanocomposites on S. mutans pathogenicity was probed.

RESULTS: It has been found that GO-Gu nanocomposites were antibacterial to S. mutans and 10 μg/mL GO-Cu nanocomposites could inhibit the bacteria bioactivity instead of killing them. The biomass of S. mutans biofilm was significantly reduced when treated with 10 μg/mL GO-Cu nanocomposites. Also, 10 μg/mL GO-Cu nanocomposites could alter the biofilm architecture and impair exopolysaccharides production and distribution, and dysregulated the expression of exopolysaccharide-associated genes.

CONCLUSION: In all, we found low-dose GO-Cu nanocomposites could disrupt exopolysaccharide matrix assembly and further impair optimal biofilm development with minimal cytotoxicity. Therefore, GO-Cu nanocomposites can open up a new avenue for the development of alternative anti-caries biomaterials.}, } @article {pmid34823134, year = {2021}, author = {Yin, L and Li, Q and Wang, Z and Shen, X and Tu, J and Shao, Y and Song, X and Qi, K and Pan, X}, title = {The Escherichia coli type III secretion system 2 Is involved in the biofilm formation and virulence of avian Pathogenic Escherichia coli.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {79}, number = {}, pages = {101722}, doi = {10.1016/j.cimid.2021.101722}, pmid = {34823134}, issn = {1878-1667}, mesh = {Animals ; Biofilms ; Chickens ; Escherichia coli/genetics ; *Escherichia coli Infections/veterinary ; *Escherichia coli Proteins/genetics ; *Poultry Diseases ; Type III Secretion Systems ; Virulence ; Virulence Factors/genetics ; }, abstract = {The Escherichia coli type III secretion system 2 (ETT2) is found in most pathogenic E. coli strains. Although many ETT2 gene clusters carry multiple genetic mutations or deletions, ETT2 is known to be involved in bacterial virulence. To date, no studies have been conducted on the role of ETT2 in the virulence of avian pathogenic Escherichia coli (APEC), which harbours ETT2. Thus, we deleted the ETT2 of APEC strain and evaluated the phenotypes and pathogenicities of the mutant. The results showed that deletion of ETT2 had no effect on APEC growth, but significantly promoted biofilm formation. In addition, as compared to the wild-type （WT） strain, the ETT2 deletion significantly promoted adherence to and invasion of DF-1 chicken fibroblasts and facilitated survival in the sera of specific-pathogen-free chickens. Analysis of the role of ETT2 in animal infection models demonstrated that the distribution of viable bacteria in the blood and organs of chicks infected with the ΔETT2 was significantly higher than those infected with WT. The results of RNA sequencing indicated that multiple genes involved in biofilm formation, lipopolysaccharide components, fimbrial genes and virulence effector proteins are regulated by ETT2. Collectively, these results implicated ETT2 is involved in the biofilm formation and pathogenicity of APEC.}, } @article {pmid34822898, year = {2022}, author = {Ren, Q and Cui, X and Zuo, X and He, J and Zhou, Y}, title = {Assessment and optimization of the oxygen based membrane biofilm reactor as a novel technology for source-diverted greywater treatment.}, journal = {The Science of the total environment}, volume = {818}, number = {}, pages = {151763}, doi = {10.1016/j.scitotenv.2021.151763}, pmid = {34822898}, issn = {1879-1026}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Nitrogen/analysis ; Oxygen ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {The oxygen based membrane biofilm (O2-MBfR) has been proved to be a novel technology in treating greywater (GW) and response surface methodology (RSM) was used to model the removal of chemical oxygen demand (COD) and total nitrogen (TN) with operation parameters COD/TN ratio, system pH and lumen air pressure (LAP). Results indicated that the all target single factors affect GW treatment efficiency, and the regression model with central composite design (CCD) showed good agreement with the experimental results with high R[2] and R2 adj values (all >0.97) for all the target responses. Statistical evaluation revealed that system pH was the most significant parameter affecting COD and TN removal, followed by COD/TN ratio and LAP. The interaction between COD/TN ratio and system pH also played an important role on the GW treatment. The optimized maximum removal of COD (96.48%) and TN (133 g N/m[2]-day) were achieved with the COD/TN ratio 17.76 g COD/g TN, system pH 7.10 and LAP 1.00 psi. Thus, RSM combined with CCD could be used for predicting the organics and nitrogen removal during GW treatment in the O2-MBfR.}, } @article {pmid34822732, year = {2022}, author = {Zhang, Y and Deng, Y and Feng, J and Hu, J and Chen, H and Guo, Z and Gao, R and Su, Y}, title = {ToxR modulates biofilm formation in fish pathogen Vibrio harveyi.}, journal = {Letters in applied microbiology}, volume = {74}, number = {2}, pages = {288-299}, doi = {10.1111/lam.13606}, pmid = {34822732}, issn = {1472-765X}, support = {2019YFD0900105//National Key R&D Program of China/ ; 2019ZD0707//Central Public-interest Scientific Institution Basal Research Fund, CAFS/ ; 2019KZDXM043//Key Project of the Department of Education of Guangdong Province/ ; 31902415//National Natural Science Foundation of China/ ; 2019A1515011833//Natural Science Fund of Guangdong Province/ ; CARS-48//China Agriculture Research System/ ; }, mesh = {Animals ; *Bacterial Proteins/genetics ; *Biofilms/growth & development ; DNA-Binding Proteins ; Fishes ; Transcription Factors ; *Vibrio/genetics/growth & development ; Virulence ; }, abstract = {Vibrio harveyi is a common aquaculture pathogen causing diseases in a variety of aquatic animals. toxR, a conserved virulence-associated gene in vibrios, is identified in V. harveyi 345, a pathogenic strain isolated from diseased fish. In this study, to gain insight into function of ToxR in V. harveyi, an in-frame deletion of the toxR gene was constructed to reveal the role of ToxR in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, motility, extracellular protease secretion, antibiotic susceptibility, virulence by intraperitoneal injection and the ability of V. harveyi to colonize the spleen and liver tissues of the pearl gentian grouper between the wild-type (WT) and the toxR mutant. However, the deletion of toxR increased the biofilm formation. The structure of the V. harveyi biofilm was further analysed by using scanning electron microscopy (SEM) and confocal laser scanning microscopy, and the results showed that deletion of toxR increased the number and density of V. harveyi biofilm. Since biofilm production is flagella, exopolysaccharide (EPS) and lipopolysaccharide dependent, 16 of V. harveyi biofilm-related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR, the expression levels of these genes, including genes flrB, motY and mshA, flaE, flrA and gmhD, were significantly up-regulated in the ΔtoxR[+] strain as compared with the WT[+] and C-ΔtoxR strains during the early and mid-exponential, while epsG, flaA, flaE, flgD, flgE, flrB, flrC, lpxB, motY, mshA and scrG genes were inhibited because of deletion of the toxR gene in the stationary growth phase. Our results indicate that ToxR plays an important role in controlling the biofilm in V. harveyi.}, } @article {pmid34822588, year = {2021}, author = {Wang, S and Kang, OH and Kwon, DY}, title = {Bisdemethoxycurcumin Reduces Methicillin-Resistant Staphylococcus aureus Expression of Virulence-Related Exoproteins and Inhibits the Biofilm Formation.}, journal = {Toxins}, volume = {13}, number = {11}, pages = {}, pmid = {34822588}, issn = {2072-6651}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Diarylheptanoids/*pharmacology ; Enterotoxins/genetics ; Methicillin-Resistant Staphylococcus aureus/*drug effects/pathogenicity ; Staphylococcal Infections/drug therapy/microbiology ; Virulence/drug effects ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen of nosocomial infection, which is resistant to most antibiotics. Presently, anti-virulence therapy and anti-biofilm therapy are considered to be promising alternatives. In the current work, we investigated the influence of bisdemethoxycurcumin (BDMC) on the virulence-related exoproteins and the biofilm formation using a reference strain and clinic isolated strains. Western blotting, quantitative RT-PCR, and tumor necrosis factor (TNF) release assay were performed to assess the efficacy of BDMC in reducing the expression of Staphylococcus enterotoxin-related exoproteins (enterotoxin A, enterotoxin B) and α-toxin in MRSA. The anti-biofilm activity of BDMC was evaluated through a biofilm inhibition assay. The study suggests that sub-inhibitory concentrations of BDMC significantly inhibited the expression of sea, seb, and hla at the mRNA level in MRSA. Moreover, the expression of virulence-related exoproteins was significantly decreased by down-regulating accessory gene regulator agr, and the inhibition of biofilms formation was demonstrated by BDMC at sub-inhibitory concentrations. Consequently, the study suggests that BDMC may be a potential natural antibacterial agent to release the pressure brought by antibiotic resistance.}, } @article {pmid34822194, year = {2022}, author = {Reginatto, P and Joaquim, AR and Rocha, DA and Berlitz, SJ and Külkamp-Guerreiro, IC and De Andrade, SF and Fuentefria, AM}, title = {8-hydroxyquinoline and quinazoline derivatives as potential new alternatives to combat Candida spp. biofilm.}, journal = {Letters in applied microbiology}, volume = {74}, number = {3}, pages = {395-404}, doi = {10.1111/lam.13607}, pmid = {34822194}, issn = {1472-765X}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; *Candida ; Microbial Sensitivity Tests ; *Oxyquinoline ; Quinazolines ; }, abstract = {Often associated to the colonization by Candida spp. biofilm, the catheter-related infections are a serious health problem since the absence of a specific therapy. Hence, the main objective of this work was to evaluate the activity of 8-hydroxyquinoline and quinazoline derivatives on Candida spp. biofilms. A quinazoline derivative (PH100) and an 8-hydroxyquinoline derivative (PH157) were tested against nine strains of C. albicans, C. tropicalis and C. parapsilosis, and their biofilms in polystyrene microtitre plates and on polyurethane central venous catheter. The PH157 compound was incorporated into a film-forming system-type formulation and its capacity to inhibit biofilm formation on catheters was evaluated. The compounds were active against planktonic and sessile cells, as well as against the tested biofilms. PH157 compound performed better than the PH100 compound. The formulation containing PH157 presented results very similar to those of the compound in solution, which indicates that its activity was preserved. Both compounds showed activity against Candida spp. strains and their biofilm, with better PH157 activity. The formulation preserved the action of the PH157 compound, in addition, it facilitates its application on the catheter. The structural modifications that these compounds allow can generate compounds that are even more active, both against planktonic cells and biofilms.}, } @article {pmid34822058, year = {2022}, author = {Panichikkal, J and Jose, A and Sreekumaran, S and Ashokan, AK and Baby, CS and Krishnankutty, RE}, title = {Biofilm and Biocontrol Modulation of Paenibacillus sp. CCB36 by Supplementation with Zinc Oxide Nanoparticles and Chitosan Nanoparticles.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {4}, pages = {1606-1620}, pmid = {34822058}, issn = {1559-0291}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Chitosan/pharmacology ; Dietary Supplements ; *Metal Nanoparticles/chemistry ; *Nanoparticles/chemistry ; *Paenibacillus ; Spectroscopy, Fourier Transform Infrared ; *Zinc Oxide/chemistry/pharmacology ; }, abstract = {Endophytic bacteria with multi-trait plant beneficial features have applications to enhance agricultural productivity by supporting the plant growth, yield, and disease resistance. In this study, Paenibacillus sp. CCB36 was isolated from the rhizome of Curcuma caesia Roxb., and its biofilm formation and antifungal properties have been evaluated in the presence of nanoparticles. Chitosan nanoparticles (CNPs) were synthesized and characterized by UV-visible spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, high-resolution-transmission electron microscopic (HR-TEM) analysis, scanning electron microscopic (SEM) analysis, and dynamic light scattering (DLS). The effect of zinc oxide nanoparticles (ZnONPs) and CNPs on biofilm formation of Paenibacillus sp. CCB36 was evaluated by tissue culture plate assay. ZnONPs reduced its biofilm formation and was found to get modulated in the presence of CNPs as revealed by atomic force microscopy (AFM). Hence, CNPs were selected for further studies. Interestingly, biocontrol property of Paenibacillus sp. CCB36 against Rhizoctonia solani was also found to get enhanced when supplemented with chitosan nanoparticles. The results of the study indicate application of nanoparticles to improve colonization and active functioning of endophytic bacteria which can have significant application in agriculture.}, } @article {pmid34821919, year = {2021}, author = {Li, Y and Xiu, W and Yang, K and Wen, Q and Yuwen, L and Luo, Z and Liu, X and Yang, D and Xie, X and Wang, L}, title = {A multifunctional Fenton nanoagent for microenvironment-selective anti-biofilm and anti-inflammatory therapy.}, journal = {Materials horizons}, volume = {8}, number = {4}, pages = {1264-1271}, doi = {10.1039/d0mh01921f}, pmid = {34821919}, issn = {2051-6355}, mesh = {*Anti-Inflammatory Agents/pharmacology ; *Biofilms ; Hydrogen-Ion Concentration ; Reactive Oxygen Species ; }, abstract = {Bacterial biofilm infections are intractable to traditional antibiotic treatment and usually cause persistent inflammation. Chemodynamic therapy (CDT) based on the Fenton reaction has recently emerged as a promising anti-biofilm strategy. However, the therapeutic efficacy of current Fenton agents often suffers from inefficient Fenton activity and lacks anti-inflammatory capability. Herein, FePS3 nanosheets (NSs) are explored for the first time as novel microenvironment-selective therapeutic nanoagents for bacterial biofilm infections with both self-enhanced Fenton activity for an anti-biofilm effect and reactive oxygen species (ROS) scavenging properties for an anti-inflammatory effect. In biofilms with acidic microenvironments, FePS3 NSs release Fe[2+] to generate toxic ROS by Fenton reaction and reductive [P2S6][4-] to enhance the Fenton activity by reducing Fe[3+] to Fe[2+]. In the surrounding normal tissues with neutral pH, FePS3 NSs scavenge ROS by reductive [P2S6][4-] with an anti-inflammatory effect. This work demonstrates multifunctional Fenton nanoagents with microenvironment-selective ROS generation and elimination properties for effective treatment of bacterial biofilm infections with both anti-biofilm and anti-inflammatory effects.}, } @article {pmid34821433, year = {2022}, author = {Obe, T and Richards, AK and Shariat, NW}, title = {Differences in biofilm formation of Salmonella serovars on two surfaces under two temperature conditions.}, journal = {Journal of applied microbiology}, volume = {132}, number = {3}, pages = {2410-2420}, doi = {10.1111/jam.15381}, pmid = {34821433}, issn = {1365-2672}, support = {//University of Georgia/ ; }, mesh = {*Bacterial Adhesion ; Biofilms ; *Salmonella/genetics ; Serogroup ; Stainless Steel ; Temperature ; }, abstract = {AIMS: Salmonella is extremely diverse, with >2500 serovars that are genetically and phenotypically diverse. The aim of this study was to build a collection of Salmonella isolates that are genetically diverse and to evaluate their ability to form biofilm under different conditions relevant to a processing environment.

METHODS AND RESULTS: Twenty Salmonella isolates representative of 10 serovars were subtyped using Clustered regularly interspaced short palindromic repeats (CRISPR)-typing to assess the genetic diversity between isolates of each serovar. Biofilm formation of the isolates on both plastic and stainless-steel surfaces at 25 and 15°C was assessed. At 25°C, 8/20 isolates each produced strong and moderate biofilm on plastic surface compared to stainless-steel (3/20 and 13/20 respectively). At 15°C, 5/20 produced strong biofilm on plastic surface and none on stainless-steel. Several isolates produced weak biofilm on plastic (11/20) and stainless-steel (16/20) surfaces. Serovar Schwarzengrund consistently produced strong biofilm while serovars Heidelberg and Newport produced weak biofilm.

CONCLUSION: These results suggest that Salmonellae differ in their attachment depending on the surface and temperature conditions encountered, which may influence persistence in the processing environment.

These differences in biofilm formation could provide useful information for mitigation of Salmonella in processing environments.}, } @article {pmid34818957, year = {2022}, author = {Simões, LC and Gomes, IB and Sousa, H and Borges, A and Simões, M}, title = {Biofilm formation under high shear stress increases resilience to chemical and mechanical challenges.}, journal = {Biofouling}, volume = {38}, number = {1}, pages = {1-12}, doi = {10.1080/08927014.2021.2006189}, pmid = {34818957}, issn = {1029-2454}, mesh = {Biofilms ; *Disinfectants/pharmacology ; *Pseudomonas fluorescens ; Stainless Steel ; Stress, Mechanical ; }, abstract = {The effect that the hydrodynamic conditions under which biofilms are formed has on their persistence is still unknown. This study assessed the behaviour of Pseudomonas fluorescens biofilms, formed on stainless steel under different shear stress (τw) conditions (1, 2 and 4 Pa), to chemical (benzalkonium chloride - BAC, glutaraldehyde - GLUT and sodium hypochlorite - SHC) and mechanical (20 Pa) treatments (alone and combined). The biofilms formed under different τw showed different structural characteristics. Those formed under a higher τw were invariably more tolerant to chemical and mechanical stresses. SHC was the biocide which caused the highest biofilm killing and removal, followed by BAC. The sequential exposure to biocides and mechanical stress was found to be insufficient for effective biofilm control. A basal layer containing biofilm cells mostly in a viable state remained on the surface of the cylinders, particularly for the 2 and 4 Pa-generated biofilms.}, } @article {pmid34817373, year = {2021}, author = {Suwal, N and Subba, RK and Paudyal, P and Khanal, DP and Panthi, M and Suwal, N and Nassan, MA and Alqarni, M and Batiha, GE and Koirala, N}, title = {Antimicrobial and antibiofilm potential of Curcuma longa Linn. Rhizome extract against biofilm producing Staphylococcus aureus and Pseudomonas aeruginosa isolates.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {67}, number = {1}, pages = {17-23}, doi = {10.14715/cmb/2021.67.1.3}, pmid = {34817373}, issn = {1165-158X}, mesh = {Alkaloids/pharmacology ; Anti-Bacterial Agents/chemistry/pharmacology ; Anti-Infective Agents/chemistry/*pharmacology ; Bacterial Infections/microbiology/prevention & control ; Biofilms/*drug effects/growth & development ; Curcuma/*chemistry ; Flavonoids/pharmacology ; Humans ; Microbial Sensitivity Tests/methods ; Phenols/pharmacology ; Plant Extracts/chemistry/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Rhizome/*chemistry ; Staphylococcus aureus/*drug effects/physiology ; Terpenes/pharmacology ; }, abstract = {More than 65% of all human bacterial infection are associated with biofilm. Bacteria in such biofilms are 10 to 1000-fold more resistant to antibiotics than free living bacteria cells. Organisms such as S. aureus and P. aeruginosa are responsible for a significant number of biofilm related infections. In this study, we investigated the antimicrobial and anti-biofilm activity of C. longa L. rhizome extract against biofilm producing S. aureus and P. aeruginosa isolates. The results of MIC and MBC demonstrated promising antibacterial activity of the rhizome extract. TLC and column chromatography detected various curcuminoids while phytochemical analysis also reveals presence of number of bioactive compounds such as alkaloids, flavonoids, phenolics, terpenoids, etc. Micro titer plate assay indicated significant inhibition of biofilm formation in clinical isolates treated with turmeric extract. Thus, on basis of our results turmeric extracts can be considered as natural antibiofilm and antibacterial agent.}, } @article {pmid34813807, year = {2022}, author = {Li, B and Zhang, Y and Guo, Q and He, S and Fan, J and Xu, L and Zhang, Z and Wu, W and Chu, H}, title = {Antibacterial peptide RP557 increases the antibiotic sensitivity of Mycobacterium abscessus by inhibiting biofilm formation.}, journal = {The Science of the total environment}, volume = {807}, number = {Pt 3}, pages = {151855}, doi = {10.1016/j.scitotenv.2021.151855}, pmid = {34813807}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Mycobacterium abscessus ; Peptides ; }, abstract = {Biofilm formation is an important factor for Mycobacterium abscessus to resist harsh environment and produce drug resistance. The anti-biofilm activity of a newly designed antibacterial peptide, RP557, was investigated. The effect of RP557 alone or in combination with several clinically effective antibiotics, including clarithromycin, amikacin, cefoxitin and imipenem, on M. abscessus growth in biofilms was determined. Microstructural changes in biofilms after RP557 treatment were observed by scanning electron microscope. The effect of RP557 on the viability of bacteria was determined by Syto9/PI staining and fluorescence microscopy. Finally, the potential mechanism of RP557 action on biofilm development was explored by transcriptome analysis. M. abscessus growing in biofilms showed increased resistance to antimicrobial drugs. RP557 alone exhibited only moderate anti-M. abscessus activity in vitro, but significantly increased the antibiotic sensitivity of M. abscessus in biofilms. The inhibitory effect of RP557 on biofilm formation was visualized by the scanning electron microscope; fluorescence staining demonstrated increased bacterial death in response to RP557 treatment. Furthermore, comparative analysis of transcriptomic data suggested RP557 may inhibit biofilm formation by down-regulating nitrogen and fatty acid metabolism, as well as peptidoglycan biosynthesis. As such, RP557 is a potential candidate to include in novel strategies to treat M. abscessus infections.}, } @article {pmid34812971, year = {2022}, author = {Cavalcante, LLR and Tedesco, AC and Souza-Gabriel, AE and Borges, HS and Curylofo-Zotti, FA and Corona, SAM}, title = {Photoinactivation of multispecies cariogenic biofilm mediated by aluminum phthalocyanine chloride encapsulated in chitosan nanoparticles.}, journal = {Lasers in medical science}, volume = {37}, number = {3}, pages = {2033-2043}, pmid = {34812971}, issn = {1435-604X}, support = {2019/05965-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; #2013/50181-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 130399/2021-3//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Biofilms ; *Chitosan/pharmacology ; Indoles ; *Nanoparticles ; Organometallic Compounds ; *Photochemotherapy ; Photosensitizing Agents/pharmacology ; Streptococcus mutans/physiology ; }, abstract = {This study aimed to characterize the aluminum phthalocyanine chloride (AlClPc) encapsulated in chitosan nanoparticles (CN) and apply it in antimicrobial photodynamic therapy (aPDT) on multispecies biofilm composed of Streptococcus mutans, Lactobacillus casei, and Candida albicans to analyze the antimicrobial activity and lactate production after treatment. Biofilms were formed in 24-well polystyrene plates at 37 °C for 48 h under microaerophilia. The following groups were evaluated (n = 9): as a positive control, 0.12% chlorhexidine gluconate (CHX); phosphate-buffered saline (PBS) as a negative control; 2.5% CN as release vehicle control; the dark toxicity control of the formulations used (AlClPc and AlClPc + CN) was verified in the absence of light; for aPDT, after 30 min incubation time, the photosensitizers at a final concentration of 5.8 × 10[-3] mg/mL were photoirradiated for 1 min by visible light using a LED device (AlClPc + L and AlClPc + CN + L) with 660 nm at the energy density of 100 J/cm[2]. An in vitro kit was used to measure lactate. The biofilm composition and morphology were observed by scanning electron microscopy (SEM). The antimicrobial activity was analyzed by quantifying colony forming units per mL (CFU/mL) of each microorganism. Bacterial load between groups was analyzed by ANOVA and Tukey HSD tests (α = 0.05). A lower lactate dosage was observed in the aPDT AlClPc + CN + L and CHX groups compared to the CN and AlClPc groups. The aPDT mediated by the nanoconjugate AlClPc + CN + L showed a significant reduction in the viability of S. mutans (3.18 log10 CFU/mL), L. casei (4.91 log10 CFU/mL), and C. albicans (2.09 log10 CFU/mL) compared to the negative control PBS (p < 0.05). aPDT using isolated AlClPc was similar to PBS to the three microorganisms (p > 0.05). The aPDT mediated by the nanoconjugate AlClPc + CN + L was efficient against the biofilm of S. mutans, L. casei, and C. albicans.}, } @article {pmid34810302, year = {2021}, author = {He, H and Wagner, BM and Carlson, AL and Yang, C and Daigger, GT}, title = {Recent progress using membrane aerated biofilm reactors for wastewater treatment.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {84}, number = {9}, pages = {2131-2157}, doi = {10.2166/wst.2021.443}, pmid = {34810302}, issn = {0273-1223}, mesh = {Biofilms ; *Bioreactors ; Membranes, Artificial ; Nitrogen ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {The membrane biofilm reactor (MBfR), which is based on the counter diffusion of the electron donors and acceptors into the biofilm, represents a novel technology for wastewater treatment. When process air or oxygen is supplied, the MBfR is known as the membrane aerated biofilm reactor (MABR), which has high oxygen transfer rate and efficiency, promoting microbial growth and activity within the biofilm. Over the past few decades, laboratory-scale studies have helped researchers and practitioners understand the relevance of influencing factors and biological transformations in MABRs. In recent years, pilot- to full-scale installations are increasing along with process modeling. The resulting accumulated knowledge has greatly improved understanding of the counter-diffusional biological process, with new challenges and opportunities arising. Therefore, it is crucial to provide new insights by conducting this review. This paper reviews wastewater treatment advancements using MABR technology, including design and operational considerations, microbial community ecology, and process modeling. Treatment performance of pilot- to full-scale MABRs for process intensification in existing facilities is assessed. This paper also reviews other emerging applications of MABRs, including sulfur recovery, industrial wastewater, and xenobiotics bioremediation, space-based wastewater treatment, and autotrophic nitrogen removal. In conclusion, commercial applications demonstrate that MABR technology is beneficial for pollutants (COD, N, P, xenobiotics) removal, resource recovery (e.g., sulfur), and N2O mitigation. Further research is needed to increase packing density while retaining efficient external mass transfer, understand the microbial interactions occurring, address existing assumptions to improve process modeling and control, and optimize the operational conditions with site-specific considerations.}, } @article {pmid34810036, year = {2022}, author = {Damiati, LA and Tsimbouri, MP and Hernandez, VL and Jayawarna, V and Ginty, M and Childs, P and Xiao, Y and Burgess, K and Wells, J and Sprott, MR and Meek, RMD and Li, P and Oreffo, ROC and Nobbs, A and Ramage, G and Su, B and Salmeron-Sanchez, M and Dalby, MJ}, title = {Materials-driven fibronectin assembly on nanoscale topography enhances mesenchymal stem cell adhesion, protecting cells from bacterial virulence factors and preventing biofilm formation.}, journal = {Biomaterials}, volume = {280}, number = {}, pages = {121263}, doi = {10.1016/j.biomaterials.2021.121263}, pmid = {34810036}, issn = {1878-5905}, support = {MR/R015651/1/MRC_/Medical Research Council/United Kingdom ; MR/S010343/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Bacterial Adhesion ; Biofilms ; Cell Adhesion ; Cell Differentiation ; *Fibronectins/metabolism ; Humans ; *Mesenchymal Stem Cells ; Osteogenesis ; Virulence Factors/metabolism ; }, abstract = {Post-operative infection is a major complication in patients recovering from orthopaedic surgery. As such, there is a clinical need to develop biomaterials for use in regenerative surgery that can promote mesenchymal stem cell (MSC) osteospecific differentiation and that can prevent infection caused by biofilm-forming pathogens. Nanotopographical approaches to pathogen control are being identified, including in orthopaedic materials such as titanium and its alloys. These topographies use high aspect ratio nanospikes or nanowires to prevent bacterial adhesion but these features also significantly reduce MSC adhesion and activity. Here, we use a poly (ethyl acrylate) (PEA) polymer coating on titanium nanowires to spontaneously organise fibronectin (FN) and to deliver bone morphogenetic protein 2 (BMP2) to enhance MSC adhesion and osteospecific signalling. Using a novel MSC-Pseudomonas aeruginosa co-culture, we show that the coated nanotopographies protect MSCs from cytotoxic quorum sensing and signalling molecules, enhance MSC adhesion and osteoblast differentiation and reduce biofilm formation. We conclude that the PEA polymer-coated nanotopography can both support MSCs and prevent pathogens from adhering to a biomaterial surface, thus protecting from biofilm formation and bacterial infection, and supporting osteogenic repair.}, } @article {pmid34809940, year = {2022}, author = {Kwok, TY and Ma, Y and Chua, SL}, title = {Biofilm dispersal induced by mechanical cutting leads to heightened foodborne pathogen dissemination.}, journal = {Food microbiology}, volume = {102}, number = {}, pages = {103914}, doi = {10.1016/j.fm.2021.103914}, pmid = {34809940}, issn = {1095-9998}, mesh = {*Bacteria/isolation & purification ; *Biofilms ; *Food Contamination ; Food Handling/instrumentation/*methods ; }, abstract = {The biofilm life cycle where bacteria alternate between biofilm and planktonic lifestyles poses major implications in food spoilage and gastrointestinal infections. Recent studies had shown that freshly biofilm-dispersed cells have a unique physiology from planktonic cells, raising the fundamental question if biofilm-dispersed cells and planktonic cells disseminate differently across food surfaces. Mechanical dislodging via cutting can cause biofilm dispersal and eventual food cross-contamination. Here, we showed that biofilm-dispersed bacteria from various foodborne pathogens were transferred from freshly cut surface at a higher rate to the cutting material than that of planktonic bacteria. When the cutting tool was used to cut a fresh surface, more biofilm-dispersed bacteria were disseminated from the cutting tool to the newly cut surface than planktonic bacteria. Our observations were applicable to cutting tools of various materials and cut surfaces, where polystyrene and surfaces with high water content were most susceptible to biofilm transfer, respectively. Simple washing with detergent and mechanical wiping could aid bacterial removal from cutting tools. Our work revealed that biofilm-dispersed cells were transferred at a higher rate than planktonic cells and cutting tool was an important medium for pathogen cross-contamination, thus providing insights in maintaining their cleanliness in food processing industries.}, } @article {pmid34809934, year = {2022}, author = {Fang, Y and Visvalingam, J and Zhang, P and Yang, X}, title = {Biofilm formation by Non-O157 Shiga toxin-producing Escherichia coli in monocultures and co-cultures with meat processing surface bacteria.}, journal = {Food microbiology}, volume = {102}, number = {}, pages = {103902}, doi = {10.1016/j.fm.2021.103902}, pmid = {34809934}, issn = {1095-9998}, mesh = {Biofilms/*growth & development ; Cellulose ; Coculture Techniques ; Genes, Bacterial ; Meat/*microbiology ; *Shiga-Toxigenic Escherichia coli/growth & development ; }, abstract = {This study investigated the impact of meat processing surface bacteria (MPB) on biofilm formation by non-O157 Shiga toxin-producing Escherichia coli (STEC), and potential links between biofilm formation by STEC and biofilm-related genes in their genomes. Biofilm development by 50 MPB and 6 STEC strains in mono- and co-cultures was assessed by the crystal violet staining method, and their expression of curli and cellulose was determined using the Congo red agar method. Genes (n = 141) associated with biofilm formation in the STEC strains were profiled. Biofilm formation in general correlated with cellulose and curli expression in both mono- and co-cultures. Most MPB strains had antagonistic effects on the biofilm formation of the STEC strains. Of the genes investigated, 81% were common among the STEC strains and there seems to be a gene-redundancy in biofilm formation. The inability of the O26 strain to form biofilms could be due to mutations in the rpoS gene. Truncation in the mlrA gene in the O145 strain seems not affecting its biofilm formation alone or with MPB. The O45 strain, despite having the greatest number of biofilm-related genes, did not form measurable biofilms. Overall, biofilm formation of STEC was affected by curli-cellulose expression and companion strains.}, } @article {pmid34808308, year = {2022}, author = {Li, L and He, Z and Liang, T and Sheng, T and Zhang, F and Wu, D and Ma, F}, title = {Colonization of biofilm in wastewater treatment: A review.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {293}, number = {}, pages = {118514}, doi = {10.1016/j.envpol.2021.118514}, pmid = {34808308}, issn = {1873-6424}, mesh = {Biofilms ; *Microbiota ; *Wastewater ; }, abstract = {The attachment and colonization process of microorganisms on a carrier is an interdisciplinary research field. Through a series of physical, chemical, and biological actions, the microorganisms can eventually reproduce on the carrier. This article introduces biofilm start-up and its applications, and explores the current issues to look forward to future development directions. Firstly, the mechanism of microbial film formation is analyzed from the microbial community colonization and reproduction process. Secondly, when analyzing the factors influencing microbial membrane formation, the effect of microbial properties (e.g., genes, proteins, lipids) and external conditions (i.e., carrier, operating environment, and regulation mechanism among microbial communities) were discussed in depth. Aimed at exploring the mechanisms and influencing factors of biofilm start-up, this article proposes the application measures to strengthen this process. Finally, the problems encountered and the future development direction of the technology are analyzed and prospected.}, } @article {pmid34808175, year = {2022}, author = {Manirakiza, B and Zhang, S and Addo, FG and Isabwe, A and Nsabimana, A}, title = {Exploring microbial diversity and ecological function of epiphytic and surface sediment biofilm communities in a shallow tropical lake.}, journal = {The Science of the total environment}, volume = {808}, number = {}, pages = {151821}, doi = {10.1016/j.scitotenv.2021.151821}, pmid = {34808175}, issn = {1879-1026}, mesh = {Bacteria/genetics ; Biofilms ; Eukaryota ; Geologic Sediments ; *Lakes ; *Microbiota ; }, abstract = {Microbial communities in epiphytic biofilms and surface sediments play a vital role in the biogeochemical cycles of the major chemical elements in freshwater. However, little is known about the diversity, composition, and ecological functions of microbial communities in shallow tropical lakes dominated by aquatic macrophytes. In this study, epiphytic bacterial and eukaryotic biofilm communities on submerged and floating macrophytes and surface sediments were investigated in Lake Rumira, Rwanda in August and November 2019. High-throughput sequencing data revealed that members of the phyla, including Firmicutes, Proteobacteria, Cyanobacteria, Actinobacteria, Chloroflexi, Bacteriodetes, Verrumicrobia, and Myxomycota, dominated bacterial communities, while the microeukaryotic communities were dominated by Unclassified (uncl) SAR(Stramenopiles, Alveolata, Rhizaria), Rotifers, Ascomycota, Gastrotricha, Platyhelminthes, Chloroplastida, and Arthropoda. Interestingly, the eukaryotic OTUs (operational taxonomic units) number and Shannon indices were significantly higher in sediments and epiphytic biofilms on Eicchornia crassipes than Ceratophyllum demersum (p < 0.05), while no differences were observed in bacterial OTUs number and Shannon values among substrates. Redundancy analysis (RDA) showed that water temperature, pH, dissolved oxygen (DO), total nitrogen (TN), and electrical conductivity (EC) were the most important abiotic factors closely related to the microbial community on C. demersum and E. crassipes. Furthermore, co-occurrence networks analysis (|r| > 0.7, p < 0.05) and functional prediction revealed more complex interactions among microbes on C. demersum than on E. crassipes and sediments, and those interactions include cross-feeding, parasitism, symbiosis, and predatism among organisms in biofilms. These results suggested that substrate-type and environmental factors were the strong driving forces of microbial diversity in epiphytic biofilms and surface sediments, thus shedding new insights into microbial community diversity in epiphytic biofilms and surface sediments and its ecological role in tropical lacustrine ecosystems.}, } @article {pmid34805002, year = {2021}, author = {Gloag, ES and Wozniak, DJ and Wolf, KL and Masters, JG and Daep, CA and Stoodley, P}, title = {Arginine Induced Streptococcus gordonii Biofilm Detachment Using a Novel Rotating-Disc Rheometry Method.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {784388}, pmid = {34805002}, issn = {2235-2988}, support = {R01 AI134895/AI/NIAID NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Arginine ; Biofilms ; Humans ; *Microbiota ; *Streptococcus gordonii ; }, abstract = {Oral diseases are one of the most common pathologies affecting human health. These diseases are typically associated with dental plaque-biofilms, through either build-up of the biofilm or dysbiosis of the microbial community. Arginine can disrupt dental plaque-biofilms, and maintain plaque homeostasis, making it an ideal therapeutic to combat the development of oral disease. Despite our understanding of the actions of arginine towards dental plaque-biofilms, it is still unclear how or if arginine effects the mechanical integrity of the dental plaque-biofilm. Here we adapted a rotating-disc rheometry assay, a method used to quantify marine biofilm fouling, to study how arginine treatment of Streptococcus gordonii biofilms influences biofilm detachment from surfaces. We demonstrate that the assay is highly sensitive at quantifying the presence of biofilm and the detachment or rearrangement of the biofilm structure as a function of shear stress. We demonstrate that arginine treatment leads to earlier detachment of the biofilm, indicating that arginine treatment weakens the biofilm, making it more susceptible to removal by shear stresses. Finally, we demonstrate that the biofilm disrupting affect is specific to arginine, and not a general property of amino acids, as S. gordonii biofilms treated with either glycine or lysine had mechanical properties similar to untreated biofilms. Our results add to the understanding that arginine targets biofilms by multifaceted mechanisms, both metabolic and physical, further promoting the potential of arginine as an active compound in dentifrices to maintain oral health.}, } @article {pmid34804427, year = {2021}, author = {Mohammad Zadeh, F and Zarei, H and Honarmand Jahromy, S}, title = {Type1 and 3 fimbriae phenotype and genotype as suitable markers for uropathogenic bacterial pathogenesis via attachment, cell surface hydrophobicity, and biofilm formation in catheter-associated urinary tract infections (CAUTIs).}, journal = {Iranian journal of basic medical sciences}, volume = {24}, number = {8}, pages = {1098-1106}, pmid = {34804427}, issn = {2008-3866}, abstract = {OBJECTIVES: Catheters are one of the factors for complicated urinary tract infections. Uropathogenic bacteria can attach to the catheter via cell surface hydrophobicity (CSH), form biofilms, and remain in urinary tract. The study was evaluated phenotypic and genotypic characteristics of fimbriae in Klebsiella pneumoniae and uropathogenic Escherichia coli (UPEC) isolates from patients with catheter-associated urinary tract infections (CAUTIs) and their association with biofilm formation.

MATERIALS AND METHODS: Urine specimens were collected through catheters in patients with CAUTIs. Sixty bacterial isolates were identified by biochemical tests. For determination of biofilm formation a tissue culture plate was used. Microbial adhesion to hydrocarbons (MATH) was conducted for CSH determination. The mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) were determined for type 1 and type 3 fimbriae. Finally, the presence of genes encoding fimbriae was determined by PCR.

RESULTS: All isolates showed strong CSH, biofilm capacity and MRHA phenotype. The results showed that 20% of UPEC and 23% of K. pneumoniae isolates contained MSHA phenotypes. There was a significant association between biofilm formation and MSHA phenotype in UPEC isolates. The frequency of fimA (80%) and fimH (96.6%) in K. pneumoniae isolates was higher than UPEC isolates. Both types of bacterial isolates with MSHA phenotypes harbored the fimH gene.

CONCLUSION: The phenotypic and genotypic characteristics of two bacterial species were highly similar. Also, the type of fimbriae affected bacterial biofilm formation through catheterization. It seems that fimH and mrk gene cluster subunits are suitable markers for identifying bacterial pathogenesis.}, } @article {pmid34802975, year = {2021}, author = {Govindan Nadar, R and Chackaravarthy, G and Ramachandran, G and Manoharan, N and Muhammad Zubair, S and Alharbi, NS and Alobaidi, AS and Li, WJ}, title = {Isolation and molecular identification of biofilm producing P. aeruginosa and K. pneumoniae from urinary tract infections patient urine sample.}, journal = {Journal of infection and public health}, volume = {14}, number = {12}, pages = {1875-1880}, doi = {10.1016/j.jiph.2021.11.004}, pmid = {34802975}, issn = {1876-035X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/genetics ; *Urinary Tract Infections ; }, abstract = {BACKGROUND: Recent years, multi drug resistant pathogens and their pathogenicity were increased worldwide due to unauthorized consumption of antibiotics. In addition, correlation between multi drug resistant bacteria and biofilm formation is heightened due to the production of more virulence behavior. There is no better identification methods are available for detection of biofilm producing gram negative bacteria.

MATERIALS AND METHODS: In this research work, multi drug resistant strains of Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were identified based on the specific antibiotics and third generation cephalosporin discs by disc diffusion assay. Subsequently, biofilm forming ability of selected pathogens were identified tissue culture plate and tube test. Based on the multi-drug resistant ability and biofilm production, the molecular identification of P. aeruginosa and K. pneumoniae were confirmed by PCR using universal primers.

RESULTS AND CONCLUSIONS: No zone of inhibition present around the discs of muller hinton agar plates were confirm, selected P. aeruginosa and K. pneumoniae strains were multi drug resistant pathogens. Performed third generation cephalosporin antibiotics were also highly sensitive to selected pathogens of P. aeruginosa and K. pneumoniae. Further, biofilm forming ability of selected P. aeruginosa and K. pneumoniae was confirmed by tissue culture plate and tube methods. Finally, molecular identification of P. aeruginosa and K. pneumoniae was named as P. aeruginosa and K. pneumoniae. Our result was conclude, selected P. aeruginosa and K. pneumoniae as biofilm producing pathogens and also highly resistant to current antibiotics.}, } @article {pmid34802350, year = {2021}, author = {Böllmann, J and Martienssen, M}, title = {Impact of pH conditions and the characteristics of two electrodialysis membranes on biofilm development under semi-realistic conditions.}, journal = {Biofouling}, volume = {37}, number = {9-10}, pages = {998-1005}, doi = {10.1080/08927014.2021.1999424}, pmid = {34802350}, issn = {1029-2454}, mesh = {*Biofilms ; Cations ; Hydrogen-Ion Concentration ; *Membranes, Artificial ; Wastewater ; }, abstract = {The reuse of treated wastewater for irrigation is of increasing importance. The Ecosave farming project developed a new photocatalytic electrodialysis process for desalination and hygienization. However, membrane scaling significantly reduces filtration efficiency. This study investigated biofilm development on anion and cation exchange membranes at a wide pH range in pre-treated wastewater. Epifluorescence microscopic quantification of the biofilm by cell counts and surface coverage together with 16S rDNA gene copy numbers showed stronger biofilm development on the anion exchange membrane (AEM) compared with the cation exchange membrane (CEM) with up to 10[5] cells mm[-2] and 20% surface coverage after three weeks. As the AEM biofilm developed best in neutral and a slightly alkaline pH, the CEM was colonized preferably at alkaline conditions. Extreme pH conditions strongly inhibited biofilm growth, which might help to minimize the maintenance effort by creating those conditions during the operation of the dialysis cell itself.}, } @article {pmid34802078, year = {2022}, author = {Pellegrini, MC and Okada, E and González Pasayo, RA and Ponce, AG}, title = {Prevalence of Escherichia coli strains in horticultural farms from Argentina: antibiotic resistance, biofilm formation, and phylogenetic affiliation.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {16}, pages = {23225-23236}, pmid = {34802078}, issn = {1614-7499}, mesh = {Anti-Bacterial Agents/pharmacology ; Argentina ; Biofilms ; *Drug Resistance, Bacterial ; *Escherichia coli ; Farms ; Humans ; Phylogeny ; Prevalence ; }, abstract = {Escherichia coli is the bacteria most commonly used as an indicator of fecal contamination in agricultural environments. Moreover, E. coli is categorized as a priority pathogen due to its widespread antibiotic resistance. This study aimed to characterize E. coli strains isolated from 10 horticultural farms. Isolates were obtained from samples of vegetable crops (n = 62), the surrounding soil (n = 62), poultry litter (n = 8), and groundwater (n = 6). Phyllo-grouping assignment was performed on the total of E. coli isolates. Antibiograms and quantification of the minimal inhibitory concentration (MIC) were performed with antibiotics commonly used in humans. Biofilm formation capacity was studied by quantifying cells attached to culture tubes. Overall, 21 E. coli isolates were obtained. Three phylogenetic groups (A, B1, and C) and two Escherichia clade IV and IV-V were identified in the collection by polymerase chain reaction. Sixty-seven percent of the E. coli isolates were resistant to amoxicillin-clavulanic acid and/or ampicillin. Amoxicillin MIC values ranged from 11.9 to >190.5 µg/mL and ampicillin MIC values ranged from 3 to >190.5 µg/mL. All the E. coli isolates, resistant and non-resistant, had biofilm forming capacity. The presence of phenotypic resistance on fresh produce and environmental matrices could present significant opportunities for contamination that result in health risks for consumers. To the authors' best knowledge, this is the first environmental assessment of resistant E. coli occurrence in horticultural farms in South America.}, } @article {pmid34801505, year = {2022}, author = {Chen, R and Zhou, Y}, title = {Mainstream nitrogen removal in membrane aerated biofilm reactor at minimal lumen pressure.}, journal = {The Science of the total environment}, volume = {818}, number = {}, pages = {151758}, doi = {10.1016/j.scitotenv.2021.151758}, pmid = {34801505}, issn = {1879-1026}, mesh = {*Ammonium Compounds ; Biofilms ; Bioreactors/microbiology ; Denitrification ; *Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S/genetics ; Sewage ; Wastewater ; }, abstract = {Nitrogen removal via anammox is a promising and sustainable solution in mainstream wastewater treatment. To maintain stable anammox process, competitors of anammox bacteria should be suppressed while cooperators need to be favoured. This study demonstrated a synchronous aerobic and anaerobic ammonium removal process in a membrane aerated biofilm reactor (MABR) under minimal lumen pressure. By adjusting the lumen pressure, aerobic and anaerobic ammonium oxidation rate can be synchronized to minimize interference of nitrite oxidizing bacteria (NOB) by limiting NOB's access to both oxygen and nitrite. Long-term performance indicated that PN/A in MABR could be achieved at zero positive aeration pressure. Furthermore, by connecting two MABRs in series, high total nitrogen (TN) removal efficiency of 71.1% ± 5.3% was attained with a TN removal rate of 30.1 ± 3.2 mg-N/L/d. The organic carbon present in the wastewater reduced the nitrate concentration in the effluent while not affecting the overall nitrogen removal efficiency and rate. Real-time qPCR analysis suggested that the abundance of amoA gene was relatively stable while K-strategist Nitrospira 16S rRNA gene did not surge in the long-term operation. High throughput sequencing showed that Candidatus Brocadia and uncultured anaerobic ammonium oxidizing bacteria from Chloroflexi were the most abundant anammox taxa. Denitrifiers, such as Denitratisoma may be responsible to reduce the nitrate in the effluent.}, } @article {pmid34800863, year = {2022}, author = {Zhang, Y and Qi, J and Wang, Y and Wen, J and Zhao, X and Qi, G}, title = {Comparative study of the role of surfactin-triggered signalling in biofilm formation among different Bacillus species.}, journal = {Microbiological research}, volume = {254}, number = {}, pages = {126920}, doi = {10.1016/j.micres.2021.126920}, pmid = {34800863}, issn = {1618-0623}, mesh = {*Bacillus/genetics ; *Biofilms ; Lipopeptides/metabolism ; Peptides, Cyclic/metabolism ; *Signal Transduction ; Species Specificity ; }, abstract = {The signal molecule surfactin in biofilm formation has been extensively studied in B. subtilis, but there is rare reports in other Bacillus species. In this study, we compared the surfactin-Spo0A-SinI-SinR/SlrR signalling in regulating biofilm formation amongst four Bacillus species including B. subtilis, B. amyloliquefaciens, B. velezensis, and B. licheniformis. The role of surfactin in biofilm formation was dependent on Bacillus species and strains, and the importance of surfactin was as following: B. velezensis R9 = B. amyloliquefaciens WH1 > B. licheniformis 285-3 > B. subtilis CYY. The global regulator Spo0A was essential and very conservative for biofilm formation in all four Bacillus species. The regulators SinI and SinR played different roles to regulate biofilm formation in different Bacillus species. SinI had no obvious roles in B. velezensis, B. amyloliquefaciens and B. subtilis but had a positive role in B. licheniformis. SinR had no obvious roles in B. subtilis, but played a positive role in B. velezensis, B. amyloliquefaciens and B. licheniformis. The regulator SlrR played a positive role in the biofilm formation of all four Bacillus species. Collectively, surfactin, Spo0A and SlrR are essential for the biofilm formation in all four Bacillus species, and SinR and SinI plays different roles in different Bacillus species.}, } @article {pmid34800320, year = {2022}, author = {Moliva, MV and Campra, N and Ibañez, M and Cristofolini, AL and Merkis, CI and Reinoso, EB}, title = {Capacity of adherence, invasion and intracellular survival of Streptococcus uberis biofilm-forming strains.}, journal = {Journal of applied microbiology}, volume = {132}, number = {3}, pages = {1751-1759}, doi = {10.1111/jam.15362}, pmid = {34800320}, issn = {1365-2672}, support = {PIP CONICET 2014//Research Career of CONICET/ ; PPI UNRC 2018//Research Career of CONICET/ ; }, mesh = {Animals ; Biofilms ; Cattle ; Female ; *Mastitis, Bovine ; *Streptococcal Infections ; Streptococcus/genetics ; }, abstract = {AIM: Nine Streptococcus uberis strains with different biofilm-forming profiles in relation to their capacity of adherence and invasion to MAC-T cell lines were examined. Additionally, virulence genes were also linked to adherence and invasion.

METHODS AND RESULTS: All S. uberis were able to adhere and invade the cells at different levels. UB56 strain showed the highest percentage of internalization (3.65%) and presented a moderate level of adhesion (4.6 × 10[6]). In contrast, UB152, the most adherent strain (8.7 × 10[6]) showed a low capacity to internalize (0.65%). Eight strains were able to persist intracellularly over 96 h regardless of their adherence or invasion level. Statistical analysis between biofilm-forming ability and the adhesion capacity showed no significant differences. Presence of virulence genes involved in the adhesion process (gapC, hasABC, lbp, pauA and sua) showed that the strains harboured different genes and seven patterns could be observed.

CONCLUSION: Statistical analysis showed no correlation between the virulence gene patterns and the adhesion capacity or the percentage of internalization. Biofilm-forming ability did not influence the invasion capacity. Likewise, adherence and invasion capacity may be strain dependent.

Findings from this study provide new insights on biofilm and invasion capacity of S. uberis strains. Results could help to design adequate control strategies.}, } @article {pmid34798360, year = {2021}, author = {Chen, Q and Zhang, X and Xie, Q and Lee, YH and Lee, JS and Shi, H}, title = {Microplastics habituated with biofilm change decabrominated diphenyl ether degradation products and thyroid endocrine toxicity.}, journal = {Ecotoxicology and environmental safety}, volume = {228}, number = {}, pages = {112991}, doi = {10.1016/j.ecoenv.2021.112991}, pmid = {34798360}, issn = {1090-2414}, abstract = {Microplastics (MPs) are rapidly colonized by microbial biofilms in a natural aquatic environment, and the nature of the microbial community and type of MP can result in different degradation products of organic pollutants. Here, we quantified the degradation products of a ubiquitously detected pollutant, decabrominated diphenyl ether (BDE-209), under both light-only and biota conditions and in the absence or presence of three kinds of MPs, styrofoam polystyrene, hard polyamide, and polypropylene film. The results showed that the BDE-209 concentration increased by 0.7-2.8 fold in the presence of MPs, probably due to the "sustained release" desorption effect. Under light-only conditions, the penta- and hexa-BDE concentrations in the presence of styrofoam or hard MPs were significantly reduced, which can be deemed a beneficial effect. However, when biota were present, the debromination products increased with the addition of MPs, particularly in the presence of styrofoam MPs. These products caused a 1.7-fold upregulation in triiodothyronine content and a 5.9-fold upregulation of thyroid stimulating hormone β expression in zebrafish larvae. The increase in debromination products could be attributed to the distinct high abundance of the bacteria Chloroflexi, Proteobacteria, and Basidiomycotina on styrofoam MPs that can participate in pollutant degradation. Collectively, our results indicate that MPs can alter the degradation pathways of BDE-209 and increase the toxicity to the endocrine system and the thyroid in aquatic organisms.}, } @article {pmid34798247, year = {2022}, author = {Cayetano, RDA and Kim, GB and Park, J and Yang, YH and Jeon, BH and Jang, M and Kim, SH}, title = {Biofilm formation as a method of improved treatment during anaerobic digestion of organic matter for biogas recovery.}, journal = {Bioresource technology}, volume = {344}, number = {Pt B}, pages = {126309}, doi = {10.1016/j.biortech.2021.126309}, pmid = {34798247}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; *Biofuels ; *Bioreactors ; Methane ; }, abstract = {The efficiency of anaerobic digestion could be increased by promoting microbial retention through biofilm development. The inclusion of certain types of biofilm carriers has differentiated existing AD biofilm reactors through their respective mode of biofilm growth. Bacteria and archaea engaged in methanogenesis during anaerobic processes potentially build biofilms by adhering or attaching to biofilm carriers. Meta-analyzed results depicted varying degrees of biogas enhancement within AD biofilm reactors. Furthermore, different carrier materials highly induced the dynamicity of the dominant microbial population in each system. It is suggested that the promotion of surface contact and improvement of interspecies electron transport have greatly impacted the treatment results. Modern spectroscopy techniques have been and will continue to give essential information regarding biofilm's composition and structural organization which can be useful in elucidating the added function of this special layer of microbial cells.}, } @article {pmid34795110, year = {2021}, author = {Ciesla, S and Lawnicka, A and Bak, M and Pluta, P and Davì, A and Veroux, M and Murawa, D}, title = {Operating room environment assessment and biofilm risk for breast implants. A case series.}, journal = {Annali italiani di chirurgia}, volume = {92}, number = {}, pages = {505-508}, pmid = {34795110}, issn = {2239-253X}, mesh = {Biofilms ; *Breast Implantation ; *Breast Implants/adverse effects ; *Breast Neoplasms/etiology/surgery ; Female ; Humans ; *Lymphoma, Large-Cell, Anaplastic/epidemiology/etiology/surgery ; Operating Rooms ; }, abstract = {AIM: Breast implant-associated anaplastic large cell lymphoma, is a rare cancer. Several theories are speculated that may constitute its etiological factors. None of them has been clearly proven. The case report we present is intended to indicate the leading cause of this disease entity.

CASE PRESENTATION: Air samples taken in varying conditions at appropriate intervals by the MicroFlow Alfa 90 device in the operating room during five breast implant surgery were analyzed. Samples were taken four times during each operation. After the air was taken and delivered to the laboratory, the plates were immediately incubated under aerobic conditions. The incubation was carried out for up to 7 days. It has been shown that there is a significant difference between the total number of microorganisms during air intake carried out without and with the supply of air to purify the area in a given area by air recirculation of the operating block and cleaning it from bacteria and particles. No air colony-forming units were grown from air samples taken in the supply. However, from air samples taken without blowing, they were raised in various quantities.

CONCLUSION: Laminar free airflow used in operating room conditions significantly reduces the risk of infection of the surgical site, and thus may reduce the risk of developing breast implant-associated anaplastic large cell lymphoma.

KEY WORDS: BIA-ALCL ethiological factors, Biofilm, Breast implants, Laminar air flow, Surgical site infections.}, } @article {pmid34792719, year = {2021}, author = {Babushkina, IV and Mamonova, IA and Ulyanov, VY and Gladkova, EV and Shpinyak, SP}, title = {Antibiotic Susceptibility of Staphylococcus aureus Plankton and Biofilm Forms Isolated in Implant-Associated Infection.}, journal = {Bulletin of experimental biology and medicine}, volume = {172}, number = {1}, pages = {46-48}, pmid = {34792719}, issn = {1573-8221}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/pharmacology ; Drug Resistance, Multiple, Bacterial/physiology ; Fluoroquinolones/pharmacology ; Microbial Sensitivity Tests ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/*drug therapy/microbiology ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects/growth & development/isolation & purification ; Vancomycin/pharmacology ; }, abstract = {Comparison of activity of antibiotics against Staphylococcus aureus strains in their plankton form and in biofilms of varying maturity showed that the concentrations of antibiotics causing death of 90% S. aureus strains (MIC90) in their plankton form was 0.07-2.80 μg/ml and significantly (p<0.05) differed from MIC90 concentrations (3-245 μg/ml) for the strains in 24 and 48 h biofilms. MIC90 value was affected by the degree of biofilm maturity: microbial resistance in 48-h biofilms for all analyzed antibiotics was significantly (p<0.05) higher than in 24-h biofilms.}, } @article {pmid34790584, year = {2021}, author = {Medina-Alarcón, KP and Tobias da Silva, IP and Ferin, GG and Pereira-da-Silva, MA and Marcos, CM and Dos Santos, MB and Regasini, LO and Chorilli, M and Mendes-Giannini, MJS and Pavan, FR and Fusco-Almeida, AM}, title = {Mycobacterium tuberculosis and Paracoccidioides brasiliensis Formation and Treatment of Mixed Biofilm In Vitro.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {681131}, pmid = {34790584}, issn = {2235-2988}, mesh = {Biofilms ; Humans ; Microbial Sensitivity Tests ; *Mycobacterium tuberculosis ; *Paracoccidioides ; }, abstract = {Co-infection of Mycobacterium tuberculosis and Paracoccidioides brasiliensis, present in 20% in Latin America, is a public health problem due to a lack of adequate diagnosis. These microorganisms are capable of forming biofilms, mainly in immunocompromised patients, which can lead to death due to the lack of effective treatment for both diseases. The present research aims to show for the first time the formation of mixed biofilms of M. tuberculosis and P. brasiliensis (Pb18) in vitro, as well as to evaluate the action of 3'hydroxychalcone (3'chalc) -loaded nanoemulsion (NE) (NE3'chalc) against monospecies and mixed biofilms, the formation of mixed biofilms of M. tuberculosis H37Rv (ATCC 27294), 40Rv (clinical strains) and P. brasiliensis (Pb18) (ATCC 32069), and the first condition of formation (H37Rv +Pb18) and (40Rv + Pb18) and second condition of formation (Pb18 + H37Rv) with 45 days of total formation time under both conditions. The results of mixed biofilms (H37Rv + Pb18) and (40Rv + Pb18), showed an organized network of M. tuberculosis bacilli in which P. brasiliensis yeasts are connected with a highly extracellular polysaccharide matrix. The (Pb18 + H37Rv) showed a dense biofilm with an apparent predominance of P. brasiliensis and fragments of M. tuberculosis. PCR assays confirmed the presence of the microorganisms involved in this formation. The characterization of NE and NE3'chalc displayed sizes from 145.00 ± 1.05 and 151.25 ± 0.60, a polydispersity index (PDI) from 0.20± 0.01 to 0.16± 0.01, and zeta potential -58.20 ± 0.92 mV and -56.10 ± 0.71 mV, respectively. The atomic force microscopy (AFM) results showed lamellar structures characteristic of NE. The minimum inhibitory concentration (MIC) values of 3'hidroxychalcone (3'chalc) range from 0.97- 7.8 µg/mL and NE3'chalc from 0.24 - 3.9 µg/mL improved the antibacterial activity when compared with 3'chalc-free, no cytotoxicity. Antibiofilm assays proved the efficacy of 3'chalc-free incorporation in NE. These findings contribute to a greater understanding of the formation of M. tuberculosis and P. brasiliensis in the mixed biofilm. In addition, the findings present a new possible NE3'chalc treatment alternative for the mixed biofilms of these microorganisms, with a high degree of relevance due to the lack of other treatments for these comorbidities.}, } @article {pmid34790509, year = {2021}, author = {Chatterjee, S and Paul, P and Chakraborty, P and Das, S and Sarker, RK and Sarkar, S and Das, A and Tribedi, P}, title = {Cuminaldehyde exhibits potential antibiofilm activity against Pseudomonas aeruginosa involving reactive oxygen species (ROS) accumulation: a way forward towards sustainable biofilm management.}, journal = {3 Biotech}, volume = {11}, number = {11}, pages = {485}, pmid = {34790509}, issn = {2190-572X}, abstract = {Pseudomonas aeruginosa often causes various acute and chronic infections in humans exploiting biofilm. Molecules interfering with microbial biofilm formation could be explored for the sustainable management of infections linked to biofilm. Towards this direction, the antimicrobial and antibiofilm activity of cuminaldehyde, an active ingredient of the essential oil of Cuminum cyminum was tested against Pseudomonas aeruginosa. In this regard, the minimum inhibitory concentration (MIC) of cuminaldehyde was found to be 150 μg/mL against the test organism. Experiments such as crystal violet assay, estimation of total biofilm protein, fluorescence microscopy and measurement of extracellular polymeric substances (EPS) indicated that the sub-MIC doses (up to 60 µg/mL) of cuminaldehyde demonstrated considerable antibiofilm activity without showing any antimicrobial activity to the test organism. Moreover, cuminaldehyde treatment resulted in substantial accumulation of cellular reactive oxygen species (ROS) that led to the inhibition of microbial biofilm formation. To this end, the exposure of ascorbic acid was found to restore the biofilm-forming ability of the cuminaldehyde-treated cells. Besides, a noticeable reduction in proteolytic activity was also observed when the organism was treated with cuminaldehyde. Taken together, the results demonstrated that cuminaldehyde could be used as a promising molecule to inhibit the biofilm formation of Pseudomonas aeruginosa.}, } @article {pmid34789754, year = {2021}, author = {Nijjer, J and Li, C and Zhang, Q and Lu, H and Zhang, S and Yan, J}, title = {Mechanical forces drive a reorientation cascade leading to biofilm self-patterning.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {6632}, pmid = {34789754}, issn = {2041-1723}, support = {DP2 GM146253/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion/genetics/physiology ; Biofilms/*growth & development ; Biomechanical Phenomena ; Models, Biological ; Mutation ; Vibrio cholerae/cytology/physiology ; }, abstract = {In growing active matter systems, a large collection of engineered or living autonomous units metabolize free energy and create order at different length scales as they proliferate and migrate collectively. One such example is bacterial biofilms, surface-attached aggregates of bacterial cells embedded in an extracellular matrix that can exhibit community-scale orientational order. However, how bacterial growth coordinates with cell-surface interactions to create distinctive, long-range order during biofilm development remains elusive. Here we report a collective cell reorientation cascade in growing Vibrio cholerae biofilms that leads to a differentially ordered, spatiotemporally coupled core-rim structure reminiscent of a blooming aster. Cell verticalization in the core leads to a pattern of differential growth that drives radial alignment of the cells in the rim, while the growing rim generates compressive stresses that expand the verticalized core. Such self-patterning disappears in nonadherent mutants but can be restored through opto-manipulation of growth. Agent-based simulations and two-phase active nematic modeling jointly reveal the strong interdependence of the driving forces underlying the differential ordering. Our findings offer insight into the developmental processes that shape bacterial communities and provide ways to engineer phenotypes and functions in living active matter.}, } @article {pmid34788062, year = {2022}, author = {Uhlich, GA and Koppenhöfer, HS and Gunther, NW and Ream, AR}, title = {Control of Escherichia coli Serotype O157:H7 Motility and Biofilm Formation by Salicylate and Decanoate: MarA/SoxS/Rob and pchE Interactions.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {2}, pages = {e0189121}, pmid = {34788062}, issn = {1098-5336}, mesh = {*Biofilms/drug effects ; DNA-Binding Proteins/genetics ; *Decanoates/pharmacology ; *Escherichia coli O157/drug effects/physiology ; *Escherichia coli Proteins/genetics ; Gene Expression Regulation, Bacterial ; Humans ; *Salicylates/pharmacology ; Serogroup ; Trans-Activators/genetics ; }, abstract = {Prophage-encoded Escherichia coli O157:H7 transcription factor (TF), PchE, inhibits biofilm formation and attachment to cultured epithelial cells by reducing curli fimbriae expression and increasing flagella expression. To identify pchE regulators that might be used in intervention strategies to reduce environmental persistence or host infections, we performed a computational search of O157:H7 strain PA20 pchE promoter sequences for binding sites used by known TFs. A common site shared by MarA/SoxS/Rob TFs was identified and the typical MarA/Rob inducers, salicylate and decanoate, were tested for biofilm and motility effects. Sodium salicylate, a proven biofilm inhibitor, but not sodium decanoate, strongly reduced O157:H7 biofilms by a pchE-independent mechanism. Both salicylate and decanoate enhanced O157:H7 motility dependent on pchE using media and incubation temperatures optimum for culturing human epithelial cells. However, induction of pchE by salicylate did not activate the SOS response. MarA/SoxS/Rob inducers provide new potential agents for controlling O157:H7 interactions with the host and its persistence in the environment. IMPORTANCE There is a need to develop E. coli serotype O157:H7 nonantibiotic interventions that do not precipitate the release and activation of virulence factor-encoded prophage and transferrable genetic elements. One method is to stimulate existing regulatory pathways that repress bacterial persistence and virulence genes. Here we show that certain inducers of MarA and Rob have that ability, working through both pchE-dependent and pschE-independent pathways.}, } @article {pmid34787954, year = {2022}, author = {Xia, L and Tian, J and Yue, T and Cao, H and Chu, J and Cai, H and Zhang, W}, title = {Pillar[5]arene-Based Acid-Triggered Supramolecular Porphyrin Photosensitizer for Combating Bacterial Infections and Biofilm Dispersion.}, journal = {Advanced healthcare materials}, volume = {11}, number = {4}, pages = {e2102015}, doi = {10.1002/adhm.202102015}, pmid = {34787954}, issn = {2192-2659}, mesh = {*Bacterial Infections/drug therapy ; Biofilms ; Calixarenes ; Humans ; *Photochemotherapy ; Photosensitizing Agents/pharmacology ; *Porphyrins/pharmacology ; Quaternary Ammonium Compounds ; }, abstract = {The treatment of pathogenic bacterial infection has long been the most serious threat to human life and attracted widespread attention. Herein, a supramolecular photosensitizer platform based on carboxylatopillar[5]arene (CP5) and tetrafluorophenyl porphyrin functionalized with a quaternary ammonium group (TFPP-QA) for combating bacteria and dispersing biofilm via photodynamic treatment is constructed. By introducing the host macrocycle CP5 and host-guest interaction, the supramolecular photosensitizer has great biocompatibility and acid responsiveness. On the one hand, the acid-triggered dissociation of TFPP-QA/CP5 could induce the porphyrin photosensitizer to target bacterial cells and disrupt the charge balance of bacterial membranes, enhance the permeability of the bacterial membrane. On the other hand, the TFPP-QA/CP5 antibacterial platform possesses superb reactive oxygen species (ROS) generation capability under light irradiation, leading to enhanced photodynamic antibacterial efficacy. The in vitro and in vivo studies show that the supramolecular photosensitizers exhibit high antibacterial efficiency and biofilm dissipation effect under 660 nm light irradiation. Therefore, it is anticipated that the rational design and integration of photosensitizers and quaternary ammonium compounds through the supramolecular strategy would provide a promising prospect for clinical photodynamic antimicrobial therapy.}, } @article {pmid34787464, year = {2021}, author = {Colombari, B and Alfano, G and Gamberini, C and Cappelli, G and Blasi, E}, title = {EDTA and Taurolidine Affect Pseudomonas aeruginosa Virulence In Vitro-Impairment of Secretory Profile and Biofilm Production onto Peritoneal Dialysis Catheters.}, journal = {Microbiology spectrum}, volume = {9}, number = {3}, pages = {e0104721}, pmid = {34787464}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Load/drug effects ; Biofilms/drug effects/growth & development ; Catheter-Related Infections/*drug therapy/microbiology/prevention & control ; Catheters, Indwelling/microbiology ; Drug Therapy, Combination ; Edetic Acid/*pharmacology ; Humans ; Peritoneal Dialysis/adverse effects ; Peritonitis/drug therapy/microbiology ; Pseudomonas Infections/*drug therapy/prevention & control ; Pseudomonas aeruginosa/*drug effects/growth & development/pathogenicity ; Taurine/*analogs & derivatives/pharmacology ; Thiadiazines/*pharmacology ; Virulence/drug effects ; }, abstract = {Peritoneal catheter-associated biofilm infection is reported to be the main cause of refractory peritonitis in peritoneal dialysis patients. The application of antimicrobial lock therapy, based on results on central venous catheters, may be a promising option for treatment of biofilm-harboring peritoneal catheters. This study investigated the effects of two lock solutions, EDTA and taurolidine, on an in vitro model of Pseudomonas aeruginosa biofilm-related peritoneal catheter infection. Silicone peritoneal catheters were incubated for 24 h with a bioluminescent strain of P. aeruginosa. Then, serial dilutions of taurolidine and/or EDTA were applied (for 24 h) once or twice onto the contaminated catheters, and P. aeruginosa viability/persistence were evaluated in real time up to 120 h using a Fluoroskan reader. On selected supernatants, high-performance liquid chromatography mass spectrometry (HPLC-MS) analysis was performed to measure the production of autoinducers (AI), phenazines, and pyocyianines. Taurolidine alone or in combination with EDTA caused a significant decrease of bacterial load and biofilm persistence on the contaminated catheters. The treatment did not lead to the sterilization of the devices, yet it resulted in a substantial destructuration of the catheter-associated P. aeruginosa biofilm. HPLC-MS analysis showed that the treatment of biofilm-harboring catheters with taurolidine and EDTA also affected the secretory activity of the pathogen. EDTA and taurolidine affect P. aeruginosa biofilm produced on peritoneal catheters and profoundly compromise the microbial secretory profile. Future studies are needed to establish whether such lock solutions can be used to render peritoneal catheter-related infections more susceptible to antibiotic treatment. IMPORTANCE An in vitro model allows studies on the mechanisms by which the lock solutions exert their antimicrobial effects on catheter-associated biofilm, thus providing a better understanding of the management of devise-associated infections.}, } @article {pmid34783647, year = {2021}, author = {Holden, ER and Yasir, M and Turner, AK and Wain, J and Charles, IG and Webber, MA}, title = {Massively parallel transposon mutagenesis identifies temporally essential genes for biofilm formation in Escherichia coli.}, journal = {Microbial genomics}, volume = {7}, number = {11}, pages = {}, pmid = {34783647}, issn = {2057-5858}, support = {BB/R012504/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms ; Escherichia coli/genetics ; *Escherichia coli Infections/genetics ; *Escherichia coli Proteins/genetics ; Genes, Essential ; Humans ; Mutagenesis ; }, abstract = {Biofilms complete a life cycle where cells aggregate, grow and produce a structured community before dispersing to colonize new environments. Progression through this life cycle requires temporally controlled gene expression to maximize fitness at each stage. Previous studies have largely focused on identifying genes essential for the formation of a mature biofilm; here, we present an insight into the genes involved at different stages of biofilm formation. We used TraDIS-Xpress, a massively parallel transposon mutagenesis approach using transposon-located promoters to assay the impact of disruption or altered expression of all genes in the genome on biofilm formation. We identified 48 genes that affected the fitness of cells growing in a biofilm, including genes with known roles and those not previously implicated in biofilm formation. Regulation of type 1 fimbriae and motility were important at all time points, adhesion and motility were important for the early biofilm, whereas matrix production and purine biosynthesis were only important as the biofilm matured. We found strong temporal contributions to biofilm fitness for some genes, including some where expression changed between being beneficial or detrimental depending on the stage at which they are expressed, including dksA and dsbA. Novel genes implicated in biofilm formation included zapE and truA involved in cell division, maoP in chromosome organization, and yigZ and ykgJ of unknown function. This work provides new insights into the requirements for successful biofilm formation through the biofilm life cycle and demonstrates the importance of understanding expression and fitness through time.}, } @article {pmid34780837, year = {2022}, author = {Dong, Y and Sui, M and Jiang, Y and Wu, J and Wang, X}, title = {Dibutyl phthalate weakens the role of electroactive biofilm as an efficient wastewater handler and related mechanism.}, journal = {The Science of the total environment}, volume = {807}, number = {Pt 2}, pages = {151612}, doi = {10.1016/j.scitotenv.2021.151612}, pmid = {34780837}, issn = {1879-1026}, mesh = {Biofilms ; *Dibutyl Phthalate/toxicity ; Electrons ; Extracellular Polymeric Substance Matrix ; *Wastewater ; }, abstract = {Plasticizer plays an imperceptible role in interfering with the structure and function of wastewater biofilms, but the inherent influence mechanism still remains unknown. Here, the responses in electrochemical, structural, microbial properties of electroactive biofilm (EAB) to plasticizer (dibutyl phthalate, DBP) were comprehensively elucidated, especially for the property variation of extracellular polymeric substances (EPS). The biofilm-0 in DBP-absent environment contributed to 22.9% and 63.9% higher current, compared to those in 1 mg/L and 10 mg/L DBP environment (biofilm-1 and biofilm-10). Chronic exposure to high-concentration DBP significantly boosted the content and distribution width of polysaccharide in EPS, but the electron exchange capacity of EPS decreased 76.6% to 0.146 μmol e[-]/mg EPS for biofilm-10. The bacteria were subjected to metabolic function loss, in terms of esterase activity and membrane integrity, by using flow cytometry. The DBP exposure also imposed selective pressure on enrich EPS-secretion-related bacteria, while the Geobacter species decreased from 71.2% (biofilm-0) to 55.8% (biofilm-10). Consequently, the DBP exposure suppressed the pollutant degradation rate, which provided new insights into the EAB role as a promising core for wastewater treatment in plasticizer-existing environments.}, } @article {pmid34780540, year = {2021}, author = {El-Zamkan, MA and Mohamed, HMA}, title = {Antimicrobial resistance, virulence genes and biofilm formation in Enterococcus species isolated from milk of sheep and goat with subclinical mastitis.}, journal = {PloS one}, volume = {16}, number = {11}, pages = {e0259584}, pmid = {34780540}, issn = {1932-6203}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Enterococcus/*drug effects/*genetics ; Female ; Goats ; Mastitis/*microbiology ; Milk/microbiology ; Sheep ; Virulence/genetics ; }, abstract = {This study is designed to discuss the antimicrobial resistance, virulence determinants and biofilm formation capacity of Enterococcus spp. isolated from milk of sheep and goat with subclinical mastitis in Qena, Egypt. The obtained isolates were identified by the VITEK2 system and 16S rDNA sequencing as E. faecalis, E. faecium, E. casseliflavus and E. hirae. Overall, E. faecalis and E. faecium were the dominant species recovered from mastitic milk samples. The antimicrobial susceptibility test evidenced multidrug resistance of the isolates against the following antimicrobials: oxacillin (89.2.%), followed by vancomycin (75.7%) and linezolid (70.3%). Also, most of these isolates (73%) could form biofilms. For example, 18.9% of Enterococcus strains formed strong biofilm, whereas 32.4% of isolates formed moderate biofilm and 21.6% of isolates formed weak biofilm. The most prevalent resistance genes found in our isolates were blaZ (54%), vanA (40%), ermB (51.4%), tetM (13.5%) and optrA (10.8%). Moreover, asa1 (37.8%), cylA (42.3%), gelE (78.4%), esp (32.4%), EF3314(48.6%) and ace (75.5%) were the most common virulence genes. A significant correlation was found between biofilm formation, multidrug resistance and virulence genes of the isolates. This study highlights several aspects of virulence and harmfulness of Enterococcus strains isolated from subclinical mastitic milk, which necessitates continuous inspection and monitoring of dairy animals.}, } @article {pmid34779756, year = {2021}, author = {Stallbaum, LR and Pruski, BB and Amaral, SC and de Freitas, SB and Wozeak, DR and Hartwig, DD}, title = {Phenotypic and molecular evaluation of biofilm formation in Klebsiella pneumoniae carbapenemase (KPC) isolates obtained from a hospital of Pelotas, RS, Brazil.}, journal = {Journal of medical microbiology}, volume = {70}, number = {11}, pages = {}, doi = {10.1099/jmm.0.001451}, pmid = {34779756}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; *Biofilms ; Brazil ; Gentian Violet ; Hospitals ; Humans ; *Klebsiella Infections/microbiology ; *Klebsiella pneumoniae/drug effects/genetics ; Microbial Sensitivity Tests ; Phenotype ; *beta-Lactamases/genetics ; }, abstract = {Introduction. A significant cause of mortality in the intensive care unit (ICU) is multidrug-resistant (MDR) Gram-negative bacteria, such as Klebsiella pneumoniae carbapenemase (KPC). Biofilm production is a key factor in KPC colonization and persistence in the host, making the treatment difficult.Gap Statement. The aim of this study was to evaluate the antibiotic resistance, molecular and phenotypic biofilm profiles of 12 KPC isolates associated with nosocomial infection in a hospital in Pelotas, Rio Grande do Sul, Brazil.Methodology. Clinical isolates were obtained from different sources, identified and characterized by antibiotic resistance and carbapenemase synthesis following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Polymerase chain reaction (PCR) was used to evaluate the presence of carbapenemase (blaKPC) and biofilm formation-associated genes (fimA, fimH, rmpA, ecpA, mrkD and wabG). Additionally, phenotypic evaluation of in vitro biofilm formation capacity was evaluated by Congo red agar (CRA) assay and the crystal violet staining method.Results. The 12 isolates evaluated in this study presented the blaKPC gene and were positive for synthesizing carbapenemases in vitro. In the carbapenem class, 83.3 % isolates were resistant and 16.7 % intermediately resistant to imipenem and meropenem. Molecular analyses found that the fimA and wabG genes were detected in 75 % of isolates, while fimH and ecpA were detected in 42 % and mrkD were detected in 8.3 % (1). The CRA assay demonstrated that all isolates were slime producers and 91.7 % (11) of isolates were classified as strong and 8.3 % (1) as moderate biofilm producers by the crystal violet staining method. The optical density (OD540nm) for strong biofilm formers ranged from 0.80±0.05 to 2.47±0.28 and was 0.55±0.12 for moderate biofilm formers.Conclusion. Our study revealed a high level of antibiotic resistance and biofilm formation in KPC isolates obtained from a hospital in Pelotas, RS, Brazil.}, } @article {pmid34778603, year = {2021}, author = {Keating, T and Lethbridge, S and Allnutt, JC and Hendon-Dunn, CL and Thomas, SR and Alderwick, LJ and Taylor, SC and Bacon, J}, title = {Mycobacterium tuberculosis modifies cell wall carbohydrates during biofilm growth with a concomitant reduction in complement activation.}, journal = {Cell surface (Amsterdam, Netherlands)}, volume = {7}, number = {}, pages = {100065}, pmid = {34778603}, issn = {2468-2330}, abstract = {The development of new vaccines for TB needs to be underpinned by an understanding of both the molecular and cellular mechanisms of host-pathogen interactions and how the immune response can be modulated to achieve protection from disease. Complement orchestrates many aspects of the innate and adaptive immune responses. However, little is known about the contribution of the complement pathways during TB disease, particularly with respect to mycobacterial phenotype. Extracellular communities (biofilms) of M. tuberculosis are found in the acellular rim of granulomas, during disease, and these are likely to be present in post-primary TB episodes, in necrotic lesions. Our study aimed to determine which mycobacterial cell wall components were altered during biofilm growth and how these cell wall alterations modified the complement response. We have shown that M. tuberculosis biofilms modified their cell wall carbohydrates and elicited reduced classical and lectin pathway activation. Consistent with this finding was the reduction of C3b/iC3b deposition on biofilm cell wall carbohydrate extracts. Here, we have highlighted the role of cell wall carbohydrate alterations during biofilm growth of M. tuberculosis and subsequent modulation of complement activation.}, } @article {pmid34778226, year = {2021}, author = {Mansouri, M and Khayam, N and Jamshidifar, E and Pourseif, T and Kianian, S and Mirzaie, A and Akbarzadeh, I and Ren, Q}, title = {Streptomycin Sulfate-Loaded Niosomes Enables Increased Antimicrobial and Anti-Biofilm Activities.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {745099}, pmid = {34778226}, issn = {2296-4185}, abstract = {One of the antibiotics used to treat infections is streptomycin sulfate that inhibits both Gram-negative and -positive bacteria. Nanoparticles are suitable carriers for the direct delivery and release of drug agents to infected locations. Niosomes are one of the new drug delivery systems that have received much attention today due to their excellent biofilm penetration property and controlled release. In this study, niosomes containing streptomycin sulfate were prepared by using the thin layer hydration method and optimized based on the size, polydispersity index (PDI), and encapsulation efficiency (EE%) characteristics. It was found that the Span 60-to-Tween 60 ratio of 1.5 and the surfactant-to-cholesterol ratio of 1.02 led to an optimum formulation with a minimum of size, low PDI, and maximum of EE of 97.8 nm, 0.27, and 86.7%, respectively. The drug release investigation showed that 50.0 ± 1.2% of streptomycin sulfate was released from the niosome in 24 h and reached 66.4 ± 1.3% by the end of 72 h. Two-month stability studies at 25° and 4°C showed more acceptable stability of samples kept at 4°C. Consequently, antimicrobial and anti-biofilm activities of streptomycin sulfate-loaded niosomes against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were found significantly higher than those of free drug, and the minimum inhibitory concentration values decreased 4- to 8-fold. Furthermore, niosome-encapsulated streptomycin up to 1,500 μg/ml exhibited negligible cytotoxicity against the human foreskin fibroblasts cell line, whereas the free drug exhibited slight cytotoxicity at this concentration. Desired physical characteristics and low toxicity of niosomal nano-carriers containing streptomycin sulfate made them a demanded candidate for the treatment of current bacterial infections and biofilms.}, } @article {pmid34777309, year = {2021}, author = {Tripathi, AK and Thakur, P and Saxena, P and Rauniyar, S and Gopalakrishnan, V and Singh, RN and Gadhamshetty, V and Gnimpieba, EZ and Jasthi, BK and Sani, RK}, title = {Gene Sets and Mechanisms of Sulfate-Reducing Bacteria Biofilm Formation and Quorum Sensing With Impact on Corrosion.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {754140}, pmid = {34777309}, issn = {1664-302X}, support = {P20 GM103443/GM/NIGMS NIH HHS/United States ; }, abstract = {Sulfate-reducing bacteria (SRB) have a unique ability to respire under anaerobic conditions using sulfate as a terminal electron acceptor, reducing it to hydrogen sulfide. SRB thrives in many natural environments (freshwater sediments and salty marshes), deep subsurface environments (oil wells and hydrothermal vents), and processing facilities in an industrial setting. Owing to their ability to alter the physicochemical properties of underlying metals, SRB can induce fouling, corrosion, and pipeline clogging challenges. Indigenous SRB causes oil souring and associated product loss and, subsequently, the abandonment of impacted oil wells. The sessile cells in biofilms are 1,000 times more resistant to biocides and induce 100-fold greater corrosion than their planktonic counterparts. To effectively combat the challenges posed by SRB, it is essential to understand their molecular mechanisms of biofilm formation and corrosion. Here, we examine the critical genes involved in biofilm formation and microbiologically influenced corrosion and categorize them into various functional categories. The current effort also discusses chemical and biological methods for controlling the SRB biofilms. Finally, we highlight the importance of surface engineering approaches for controlling biofilm formation on underlying metal surfaces.}, } @article {pmid34775379, year = {2022}, author = {Lamprokostopoulou, A and Römling, U}, title = {Yin and Yang of Biofilm Formation and Cyclic di-GMP Signaling of the Gastrointestinal Pathogen Salmonella enterica Serovar Typhimurium.}, journal = {Journal of innate immunity}, volume = {14}, number = {4}, pages = {275-292}, pmid = {34775379}, issn = {1662-8128}, mesh = {Bacterial Proteins/metabolism ; Biofilms ; Cell Communication ; *Gene Expression Regulation, Bacterial ; *Salmonella typhimurium ; Serogroup ; }, abstract = {Within the last 60 years, microbiological research has challenged many dogmas such as bacteria being unicellular microorganisms directed by nutrient sources; these investigations produced new dogmas such as cyclic diguanylate monophosphate (cyclic di-GMP) second messenger signaling as a ubiquitous regulator of the fundamental sessility/motility lifestyle switch on the single-cell level. Successive investigations have not yet challenged this view; however, the complexity of cyclic di-GMP as an intracellular bacterial signal, and, less explored, as an extracellular signaling molecule in combination with the conformational flexibility of the molecule, provides endless opportunities for cross-kingdom interactions. Cyclic di-GMP-directed microbial biofilms commonly stimulate the immune system on a lower level, whereas host-sensed cyclic di-GMP broadly stimulates the innate and adaptive immune responses. Furthermore, while the intracellular second messenger cyclic di-GMP signaling promotes bacterial biofilm formation and chronic infections, oppositely, Salmonella Typhimurium cellulose biofilm inside immune cells is not endorsed. These observations only touch on the complexity of the interaction of biofilm microbial cells with its host. In this review, we describe the Yin and Yang interactive concepts of biofilm formation and cyclic di-GMP signaling using S. Typhimurium as an example.}, } @article {pmid34775269, year = {2022}, author = {Leelapornpisid, W}, title = {Efficacy of alpha-mangostin for antimicrobial activity against endodontopathogenic microorganisms in a multi-species bacterial-fungal biofilm model.}, journal = {Archives of oral biology}, volume = {133}, number = {}, pages = {105304}, doi = {10.1016/j.archoralbio.2021.105304}, pmid = {34775269}, issn = {1879-1506}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; Enterococcus faecalis ; *Xanthones/pharmacology ; }, abstract = {OBJECTIVE: To determine the activity of alpha-mangostin on preformed bacterial-fungal multi-species biofilms in vitro, and to ascertain the impact on metabolic activity, biofilm structure and viability.

DESIGN: Inhibitory concentrations (ICs) for alpha-mangostin against planktonic cultures of Candida albicans, Enterococcus faecalis, Lactobacillus rhamnosus, and Streptococcus gordonii were determined using a standard broth microdilution method. Single and multi-species (all species 1:1:1:1) biofilms were grown on polystyrene coverslips in Roswell Park Memorial Institute Medium for 48 h. The biofilms were then exposed to 0.2% (w/v) alpha-mangostin for 24 h. These concentrations were selected based on pilot experiments and the solubility of these compounds. 2% (v/v) chlorhexidine was used as a positive control and Roswell Park Memorial Institute Medium as a negative control. The metabolic activity of the biofilms after exposure was measured using metabolic (XTT) assays. Biofilms were visualised and quantified using fluorescent BacLight™ LIVE/DEAD staining. The biofilms were assessed for cell viability by culture and colony counting (CFU/mL).

RESULTS: 8 mg/L of alpha-mangostin was cidal against planktonic bacteria and 1000 mg/L for Candida. Alpha-mangostin was most active against L. rhamonosus biofilms and least active against C. albicans biofilm (metabolism inhibited by 99% and 78%, respectively). Alpha-mangostin exposure reduced the number of viable cells in the biofilms.

CONCLUSION: Alpha-mangostin inhibited the metabolic activity of bacterial-fungal biofilms effectively. The anti-biofilm activity of alpha-mangostin was comparable to chlorhexidine and thus has potential as a novel agent for endodontic therapy.}, } @article {pmid34775066, year = {2022}, author = {Benine-Warlet, J and Brenes-Alvarado, A and Steiner-Oliveira, C}, title = {Potassium iodide enhances inactivation of Streptococcus mutans biofilm in antimicrobial photodynamic therapy with red laser.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {37}, number = {}, pages = {102622}, doi = {10.1016/j.pdpdt.2021.102622}, pmid = {34775066}, issn = {1873-1597}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; Lasers ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Potassium Iodide/pharmacology ; Streptococcus mutans ; }, abstract = {OBJECTIVE: To evaluate the effect of potassium iodide (KI) addition on antimicrobial photodynamic therapy (aPDT) mediated by red laser (λ = 660 nm) and methylene blue in Streptococcus mutans biofilm model.

METHODS: S. mutans biofilms were cultured in 96-well plates containing BHI broth with 1% sucrose for 18 h, 10% CO2 and 37 °C and divided in groups (n = 3, in triplicate): C (NaCl 0.9%); CX (0.2% chlorhexidine); P (photosensitizer); KI (10, 25 and 50 mM); PKI (10, 25 and 50 mM); L (L1: 100 J/cm[2], 9 J; L2: 200 J/cm[2], 18 J); PL (photosensitizer + L1 or L2); KIL (KI at 10, 25 and 50 mM + L1 or L2); and PKIL (photosensitizer + 10, 25 and 50 mM KI + L1 or L2). Biofilms were submitted to three pre-irradiation (PI) times (5, 10, and 15 min). After the treatments, microbial counting's reduction was analyzed by Kruskal-Wallis and post-hoc Dunn's tests, respectively, and the interaction between light parameters and the PI times by two-way ANOVA (p < 0.05).

RESULTS: The S. mutans viability significantly reduced in all aPDT groups, in the presence or absence of KI (p < 0.05). For all PI times, PKIL groups (10, 25, and 50 mM) significantly differed from PL groups (p < 0.05) with a reduction of 9.0 logs reached at 50 mM of KI with 15 min of PI, irradiated at 18 J. We found no significant interaction between PI time and irradiation (p > 0.05).

CONCLUSION: The addition of KI to PDT mediated by methylene blue and red laser promoted an additional effect in reducing the microbial viability of S. mutans biofilm.}, } @article {pmid34775052, year = {2022}, author = {Li, J and Zheng, L and Ye, C and Zhou, Z and Ni, B and Zhang, X and Liu, H}, title = {Unveiling organic loading shock-resistant mechanism in a pilot-scale moving bed biofilm reactor-assisted dual-anaerobic-anoxic/oxic system for effective municipal wastewater treatment.}, journal = {Bioresource technology}, volume = {347}, number = {}, pages = {126339}, doi = {10.1016/j.biortech.2021.126339}, pmid = {34775052}, issn = {1873-2976}, mesh = {Anaerobiosis ; *Biofilms ; Bioreactors ; Denitrification ; Nitrogen/analysis ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid ; Wastewater/analysis ; *Water Purification ; }, abstract = {Microbial biomass and activity are frequently subjected to organic loading shock (OLS) from decentralized municipal wastewater. A hybrid moving bed biofilm reactor-assisted dual-anaerobic-anoxic/oxic system (D-A[2]MBBR) was established by integrating dual-anaerobic-anoxic/oxic with moving bed biofilm reactor to resist OLS for stable nutrients removal. The D-A[2]MBBR achieved 91.57% of chemical oxygen demand, 93.33% of ammonia-nitrogen, 80.20% of total nitrogen and 92.68% of total phosphorus removal, respectively, under the fluctuation of organic loading rate from 417.9 to 812.0 g COD m[-3] d[-1]. The 16S rRNA gene sequencing revealed that Gemmobacter (7.28%) was identified as dominating anoxic denitrifying genus in oxic chamber, confirming the coexistence of aerobic and anaerobic/anoxic micro-environments. This circumstance boosted simultaneous nitrification-denitrification and phosphorus removal and the microbial community evolution inside the multilayer biocarrier-attached biofilms. In general, the D-A[2]MBBR was able to provide unique, cooperative and robust bacterial consortia to form a buffer against OLS, and ensuring effluent stability.}, } @article {pmid34774351, year = {2022}, author = {Pagsuyoin, SA and Luo, J and Chain, FJ}, title = {Effects of sewer biofilm on the degradation of drugs in sewage: A microcosm study.}, journal = {Journal of hazardous materials}, volume = {424}, number = {Pt D}, pages = {127666}, doi = {10.1016/j.jhazmat.2021.127666}, pmid = {34774351}, issn = {1873-3336}, mesh = {Biofilms ; *Illicit Drugs ; Sewage ; Wastewater ; *Water Pollutants, Chemical/analysis ; }, abstract = {A thorough understanding of the in-sewer stability of chemical biomarkers is critical in applying wastewater-based surveillance of community drug use. In this study, we examined the effects of sewer biofilm on the degradation of commonly abused drugs, namely, morphine, fentanyl, cocaine, and amphetamine, in wastewater using 48-h batch degradation tests. The experiments were designed to distinguish among abiotic, biochemical, and physical degradation processes, and used mature biofilm obtained from an actual sewer line. Parallel microcosm tests were conducted using wastewater with and without suspended biofilm. Results indicate that first order kinetics describe the degradation of the drugs in both wastewater and wastewater-biofilm microcosms. Amphetamine was most stable in all microcosms, with a maximum removal of only 34% after 48 h. Abiotic chemical transformation played a major role in the degradation of morphine (kab = 0.018 h[-1]), fentanyl (kab = 0.022 h[-1]) and cocaine (kab = 0.049 h[-1]) in wastewater. Fentanyl removal from wastewater was also influenced by the presence of biofilm (kf = 0.015 h[-1]). This study is the first to report on the effect of sewer biofilm on fentanyl degradation, and highlights the need to account for in-sewer drug stability in wastewater-based drug use estimation, particularly for chemicals with high affinity for organics.}, } @article {pmid34772585, year = {2021}, author = {Singh, D and Sharma, D and Agarwal, V}, title = {Screening of anti-microbial, anti-biofilm activity, and cytotoxicity analysis of a designed polyherbal formulation against shigellosis.}, journal = {Journal of Ayurveda and integrative medicine}, volume = {12}, number = {4}, pages = {601-606}, pmid = {34772585}, issn = {0975-9476}, abstract = {BACKGROUND: Shigellosis is an infectious intestinal disease common in rural communities. In developing countries, shigellosis is caused predominantly by Shigella flexneri and has been determined as a major cause of morbidity and mortality.

OBJECTIVE: The study investigates the anti-biofilm, anti-microbial, and anti-shigellosis activity of a designed formulation.

MATERIALS AND METHODS: The potential of the formulation against S. flexneri (MTCC 1457) was investigated using a well-diffusion assay. Further, the effect of the designed formulation on bacterial growth and biofilm formation was analyzed by the spectrophotometry method. Anti-quorum sensing activity was analyzed using Chromobacterium violaceum CV026, a bacterial strain. Finally, the cytotoxicity of the formulation was examined by using cell line and brine shrimp lethality assay.

RESULTS: The MIC value of the aqueous extract of the formulation was 2.4 mg ml[-1] and an inhibitory zone of 23 mm was observed. On the other side, the formulation significantly inhibited the bacterial growth, biofilm formation (23.78%), violacein inhibition (27.68%) at 0.6 mg ml[-1] concentration (did not significantly affect the growth curves) and was found non-toxic in cell assay and brine shrimp lethality assay.

CONCLUSION: According to the result obtained, the designed formulation was found effective and non-toxic, so it can be used to treat shigellosis and Shigella-related infections.}, } @article {pmid34769015, year = {2021}, author = {Grande, R and Carradori, S and Puca, V and Vitale, I and Angeli, A and Nocentini, A and Bonardi, A and Gratteri, P and Lanuti, P and Bologna, G and Simeone, P and Capasso, C and De Luca, V and Supuran, CT}, title = {Selective Inhibition of Helicobacter pylori Carbonic Anhydrases by Carvacrol and Thymol Could Impair Biofilm Production and the Release of Outer Membrane Vesicles.}, journal = {International journal of molecular sciences}, volume = {22}, number = {21}, pages = {}, pmid = {34769015}, issn = {1422-0067}, mesh = {Amoxicillin/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Outer Membrane Proteins/*metabolism ; Biofilms/*drug effects ; Carbonic Anhydrase Inhibitors/*pharmacology ; Carbonic Anhydrases/*metabolism ; Cymenes/*pharmacology ; Helicobacter Infections/drug therapy/metabolism ; Helicobacter pylori/*drug effects/*metabolism ; Humans ; Peptic Ulcer/metabolism/microbiology ; Stomach Neoplasms/etiology/metabolism/microbiology ; Thymol/*pharmacology ; }, abstract = {Helicobacter pylori, a Gram-negative neutrophilic pathogen, is the cause of chronic gastritis, peptic ulcers, and gastric cancer in humans. Current therapeutic regimens suffer from an emerging bacterial resistance rate and poor patience compliance. To improve the discovery of compounds targeting bacterial alternative enzymes or essential pathways such as carbonic anhydrases (CAs), we assessed the anti-H. pylori activity of thymol and carvacrol in terms of CA inhibition, isoform selectivity, growth impairment, biofilm production, and release of associated outer membrane vesicles-eDNA. The microbiological results were correlated by the evaluation in vitro of H. pylori CA inhibition, in silico analysis of the structural requirements to display such isoform selectivity, and the assessment of their limited toxicity against three probiotic species with respect to amoxicillin. Carvacrol and thymol could thus be considered as new lead compounds as alternative H. pylori CA inhibitors or to be used in association with current drugs for the management of H. pylori infection and limiting the spread of antibiotic resistance.}, } @article {pmid34768258, year = {2022}, author = {Falk, KN and Satola, SW and Chassagne, F and Northington, GM and Quave, CL}, title = {Biofilm Production by Uropathogens in Postmenopausal Women with Recurrent and Isolated Urinary Tract Infection.}, journal = {Female pelvic medicine & reconstructive surgery}, volume = {28}, number = {4}, pages = {e127-e132}, pmid = {34768258}, issn = {2154-4212}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacteria ; Biofilms ; Cross-Sectional Studies ; Female ; Humans ; Male ; *Postmenopause ; *Urinary Tract Infections/diagnosis ; }, abstract = {OBJECTIVES: The aims of this study were to assess the in vitro biofilm-producing capabilities of uropathogens grown from a postmenopausal urogynecologic population with isolated and recurrent urinary tract infection (UTI) and to determine whether the biofilm-producing bacterial phenotype was associated with recurrent infection.

METHODS: This was an institutional review board-approved cross-sectional analysis within a large academic referral center. Uropathogens were cultured from postmenopausal women with either isolated or recurrent acute UTI and then screened for in vitro biofilm formation using crystal violet microtiter assays. Demographic and clinical variables, including pelvic floor symptoms and surgical history were collected and analyzed. A multivariate model was developed to determine whether recurrent UTI was independently associated with biofilm production.

RESULTS: Eighty-nine women were included: 67.4% White, 25.8% Black, 3.4% Asian, and 1.1% Hispanic with a mean age of 72 ± 10.5 years. Ninety-five uropathogen strains were isolated. Most uropathogens produced biofilm (n = 53, 55.8%). Uropathogens from women with recurrent UTI were significantly more likely to produce biofilm (70%) than uropathogens collected from women with isolated UTI (38.6%, P = 0.0033). Adjusting for age, prior pelvic reconstructive surgery, and body mass index, recurrent UTI bacteria were more likely to produce biofilm, compared with isolated UTI (odds ratio, 5.37; 95% confidence interval, 2.0-14.4; P = 0.001).

CONCLUSIONS: In this cohort of postmenopausal urogynecology patients, in vitro biofilm formation was more frequently observed in uropathogens isolated from women with recurrent UTI compared with women with isolated UTI. Further study is needed to assess the role of biofilms in recurrent UTIs in postmenopausal women.}, } @article {pmid34764658, year = {2021}, author = {Wang, L and Zhang, Y and Liu, S and Huang, N and Zeng, W and Xu, W and Zhou, T and Shen, M}, title = {Comparison of Anti-Microbic and Anti-Biofilm Activity Among Tedizolid and Radezolid Against Linezolid-Resistant Enterococcus faecalis Isolates.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {4619-4627}, pmid = {34764658}, issn = {1178-6973}, abstract = {BACKGROUND: The emergence and spread of linezolid-resistant Enterococcus faecalis (E. faecalis) have emerged as a serious threat to human health globally. Therefore, this study aims to compare the anti-microbic as well as the anti-biofilm activity of linezolid, tedizolid, and radezolid against linezolid-resistant E. faecalis.

METHODS: A total of 2128 E. faecalis isolates were assessed from the First Affiliated Hospital of Wenzhou Medical University from 2011 to 2019. Antibiotic sensitivity was evaluated using the micro broth dilution method. Oxazolidinone-resistant chromosomal and plasmid-borne genes such as cfr, cfr(A), cfr(B), cfr(C), cfr(D), optrA, and poxtA were detected by PCR and then sequenced to detect the presence of mutations in the domain V of the 23S rRNA and the ribosomal proteins L3, L4, and L22. Conjugation experiments were conducted using the broth method. The inhibition and eradication of biofilm were evaluated through crystal violet staining, whereas the efflux pump activities were detected by agar dilution.

RESULTS: Out of 2128 isolated E. faecalis, 71 (3.34%) were linezolid-resistant isolates in which the MICs of tedizolid and radezolid ranged from 1 to 4 μg/mL and 0.5-1 μg/mL, respectively. The MIC50/MIC90 of tedizolid and radezolid were 4 and 8-fold lower than the linezolid, respectively. Out of 71 resistant isolates, 57 (80.28%) carried optrA, 1 (1.41%) carried cfr, 4 (5.63%) carried optrA and cfr, and 6 (8.45%) carried optrA and cfr(D), with no mutations of 23S rRNA gene and ribosomal proteins L3, L4, and L22. Besides, the transfer rate of the optrA, cfr, and cfr(D) was 17.91%, 0% and 0%, respectively. Radezolid showed more effectiveness in eradicating biofilm (8 × MIC). However, tedizolid was more effective than radezolid and linezolid in inhibiting the biofilm formation (1/4 MIC, 1/8MIC, and 1/16MIC). Additionally, in combination with CCCP, the MICs of radezolid in all linezolid-resistant isolates decreased ≥4-fold.

CONCLUSION: Radezolid showed greater antimicrobial activity than tedizolid and linezolid against linezolid-resistant E. faecalis. However, both tedizolid and radezolid showed differential activity on biofilm inhibition, eradication, and efflux pump compared to linezolid. Thus, our study might bring important clinical value in the application of these drugs for resistant pathogenic strains.}, } @article {pmid34763655, year = {2021}, author = {Sutipornpalangkul, W and Nishitani, K and Schwarz, EM}, title = {Quantitative flow chamber system for evaluating in vitro biofilms and the kinetics of S. aureus biofilm formation in human plasma media.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {314}, pmid = {34763655}, issn = {1471-2180}, support = {P30 AR061307/AR/NIAMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Culture Media/analysis/*metabolism ; Humans ; Kinetics ; Plasma/metabolism/*microbiology ; Stainless Steel/analysis ; Staphylococcal Infections/blood/*microbiology ; Staphylococcus aureus/chemistry/genetics/growth & development/*physiology ; }, abstract = {BACKGROUND: It has been well established that biofilm formation on orthopaedic implants is a critical event in the pathogenesis of orthopaedic infections, yet the natural history of this process with respect to bacterial adhesion, proliferation, and glycocalyx matrix production remains poorly understood. Moreover, there are no quantitative methods yet available to assess the differences in biofilm formation between different bacterial strains or implant materials. Consequently, this study aimed to investigate the natural history of S. aureus in in vitro biofilm formation in human plasma media using a flow chamber system. Bioluminescent S. aureus strains were used to better understand the bacterial growth and biofilm formation on orthopaedic materials. Also, the effects of human plasma media were assessed by loading the chamber with Tryptic Soy Broth with 10% human plasma (TSB + HP).

RESULTS: Scanning electron microscopy (SEM) was utilized to assess the morphological appearance of the biofilms, revealing that S. aureus inoculation was required for biofilm formation, and that the phenotypes of biofilm production after 24 h inoculation with three tested strains (SH1000, UAMS-1, and USA300) were markedly different depending on the culture medium. Time course study of the bioluminescence intensity (BLI) and biofilm production on the implants due to the UAMS-1 and USA300 strains revealed different characteristics, whereby UAMS-1 showed increasing BLI and biofilm growth until peaking at 9 h, while USA300 showed a rapid increase in BLI and biofilm formation at 6 h. The kinetics of biofilm formation for both UAMS-1 and USA300 were also supported and confirmed by qRT-PCR analysis of the 16S rRNA gene. Biofilms grown in our flow chamber in the plasma media were also demonstrated to involve an upregulation of the biofilm-forming-related genes icaA, fnbA, and alt. The BLI and SEM results from K-wire experiments revealed that the in vitro growth and biofilm formation by UAMS-1 and USA300 on stainless-steel and titanium surfaces were virtually identical.

CONCLUSION: We demonstrated a novel in vitro model for S. aureus biofilm formation with quantitative BLI and SEM outcome measures, and then used this model to demonstrate the presence of strain-specific phenotypes and its potential use to evaluate anti-microbial surfaces.}, } @article {pmid34763140, year = {2022}, author = {Li, H and Du, X and Chen, C and Qi, J and Wang, Y}, title = {Integrating transcriptomics and metabolomics analysis on kojic acid combating Acinetobacter baumannii biofilm and its potential roles.}, journal = {Microbiological research}, volume = {254}, number = {}, pages = {126911}, doi = {10.1016/j.micres.2021.126911}, pmid = {34763140}, issn = {1618-0623}, mesh = {*Acinetobacter baumannii/drug effects/genetics ; *Biofilms/drug effects ; *Metabolome/drug effects ; Metabolomics ; *Pyrones/pharmacology ; *Transcriptome/drug effects ; }, abstract = {As a major secondary metabolite derived from a dominant marine filamentous fungus A7, kojic acid might confer the strain a competitive advantage in natural colonization. The bioactivities of kojic acid against bacterial growth and biofilm formation were investigated against Acinetobacter baumannii (A. baumannii) ATCC 19606. Then, transcriptomics and metabolomics were integrated to characterize the underlying mechanisms. It turned out that kojic acid exhibited a significantly suppressive impact against biofilm but a weak bacteriostatic activity. Meanwhile, a variety of transcriptional and metabolomic profiles were altered within biofilm formation as a result of kojic acid exposure. The alterations highlighted the mechanisms underlying biofilm formation, comprising of quorum sensing, fimbria assembly, bacterial virulence and metabolic plasticity, which could somewhat be hampered by kojic acid. The present study comprehensively elucidated multifactorial schemes for kojic acid combating biofilm formation of A. baumannii, which might provide mechanistic insights into the development of therapeutic strategies against this notorious pathogen. Meanwhile, our observations might shed new light on the ecological roles of kojic acid, e.g., serving as chemical deterrents for host adaptation to marine niches, which, however, awaits further validation.}, } @article {pmid34762795, year = {2021}, author = {Anderson, AC and Burnett, AJN and Constable, S and Hiscock, L and Maly, KE and Weadge, JT}, title = {A Mechanistic Basis for Phosphoethanolamine Modification of the Cellulose Biofilm Matrix in Escherichia coli.}, journal = {Biochemistry}, volume = {60}, number = {47}, pages = {3659-3669}, doi = {10.1021/acs.biochem.1c00605}, pmid = {34762795}, issn = {1520-4995}, mesh = {Biofilms ; Cellulose/chemistry/*metabolism ; Escherichia coli/chemistry/*enzymology ; Escherichia coli Proteins/chemistry/*metabolism ; Ethanolamines/chemistry/*metabolism ; Membrane Proteins/chemistry/*metabolism ; Polysaccharides, Bacterial/metabolism ; Transferases (Other Substituted Phosphate Groups)/chemistry/*metabolism ; }, abstract = {Biofilms are communities of self-enmeshed bacteria in a matrix of exopolysaccharides. The widely distributed human pathogen and commensal Escherichia coli produces a biofilm matrix composed of phosphoethanolamine (pEtN)-modified cellulose and amyloid protein fibers, termed curli. The addition of pEtN to the cellulose exopolysaccharide is accomplished by the action of the pEtN transferase, BcsG, and is essential for the overall integrity of the biofilm. Here, using the synthetic co-substrates p-nitrophenyl phosphoethanolamine and β-d-cellopentaose, we demonstrate using an in vitro pEtN transferase assay that full activity of the pEtN transferase domain of BcsG from E. coli (EcBcsG[ΔN]) requires Zn[2+] binding, a catalytic nucleophile/acid-base arrangement (Ser[278]/Cys[243]/His[396]), disulfide bond formation, and other newly uncovered essential residues. We further confirm that EcBcsG[ΔN] catalysis proceeds by a ping-pong bisubstrate-biproduct reaction mechanism and displays inefficient kinetic behavior (kcat/KM = 1.81 × 10[-4] ± 2.81 × 10[-5] M[-1] s[-1]), which is typical of exopolysaccharide-modifying enzymes in bacteria. Thus, the results presented, especially with respect to donor binding (as reflected by KM), have importantly broadened our understanding of the substrate profile and catalytic mechanism of this class of enzymes, which may aid in the development of inhibitors targeting BcsG or other characterized members of the pEtN transferase family, including the intrinsic and mobile colistin resistance factors.}, } @article {pmid34761536, year = {2022}, author = {Zheng, T and Jing, M and Gong, T and Yan, J and Zeng, J and Li, Y}, title = {Deletion of the yqeK gene leads to the accumulation of Ap4A and reduced biofilm formation in Streptococcus mutans.}, journal = {Molecular oral microbiology}, volume = {37}, number = {1}, pages = {9-21}, doi = {10.1111/omi.12356}, pmid = {34761536}, issn = {2041-1014}, mesh = {Biofilms ; *Dental Caries/microbiology ; Dinucleoside Phosphates/pharmacology ; Humans ; *Streptococcus mutans/physiology ; }, abstract = {Diadenosine-5',5'''-P1, P4-tetraphosphate (Ap4A) is a second messenger playing a crucial role in various life activities of bacteria. The increase of Ap4A expression is pleiotropic, resulting in an impairment in the formation of biofilm and other physiological functions in some bacteria. However, Ap4A function in Streptococcus mutans, an important pathogen related to dental caries, remains unknown. In this work, the Ap4A hydrolase, YqeK, was identified and characterized in S. mutans. Then, the effects of yqeK deletion on the growth, biofilm formation, and exopolysaccharide (EPS) quantification in S. mutans were determined by the assessment of the growth curve, crystal violet, and anthrone-sulfuric acid, respectively, and visualized by microscopy. The results showed that the in-frame deletion of the yqeK gene in S. mutans UA159 led to an increase in Ap4A levels, lag phase in the early growth, as well as decrease in biofilm formation and water-insoluble exopolysaccharide production. Global gene expression profile showed that the expression of 88 genes was changed in the yqeK mutant, and among these, 42 were upregulated and 46 were downregulated when compared with the wild-type S. mutans UA159. Upregulated genes were mainly involved in post-translational modification, protein turnover, and chaperones, while downregulated genes were mainly involved in carbohydrate transport and metabolism. Important virulence genes related to biofilms, such as gtfB, gtfC, and gbpC, were also significantly downregulated. In conclusion, these results indicated that YqeK affected the formation of biofilms and the expression of biofilm-related genes in S. mutans.}, } @article {pmid34760796, year = {2021}, author = {Mat-Rani, S and Chotprasert, N and Srimaneekarn, N and Choonharuangdej, S}, title = {Fungicidal Effect of Lemongrass Essential Oil on Candida albicans Biofilm Pre-established on Maxillofacial Silicone Specimens.}, journal = {Journal of International Society of Preventive & Community Dentistry}, volume = {11}, number = {5}, pages = {525-530}, pmid = {34760796}, issn = {2231-0762}, abstract = {AIMS: This in-vitro study aimed to evaluate the efficacy of lemongrass (Cymbopogon citratus) essential oil in eradicating Candida albicans biofilm pre-established on the maxillofacial silicone specimens.

MATERIALS AND METHODS: Two maxillofacial silicones, namely, MDX4-4210 and Multisil Epithetik, were used for the fabrication of 6 mm diameter disks (n = 21 for each brand of silicone). A 48-h mature C. albicans ATCC 10231 biofilm was pre-established on sterile silicone specimen. These disks were then exposed to various concentrations of lemongrass essential oil ranging from 0.31% to 5% (v/v), 20% (v/v) nystatin, and RPMI-1640 medium for 18-20 h. After exposure, the remaining viable fungal biofilm was examined by the XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide]-reduction assay. All data were analyzed by using a regression coefficient and a post hoc Tukey HSD multiple comparisons test (α = 0.05).

RESULTS: Different brands of silicone used for fabrication did not significantly affect the formation of mature C. albicans biofilm (P =0.302). A 5% (v/v) lemongrass essential oil significantly eliminated fungal biofilm by approximately 95% (P =0.031). However, less than 50% of the fungal biofilm was eliminated by the tested oil at a concentration as low as 0.31% (v/v). Furthermore, the fungicidal efficacy against C. albicans biofilm of lemongrass essential oil at 2.5% (v/v) was as potent as that of 20% (v/v) nystatin suspension (P = 0.99).

CONCLUSION: Lemongrass essential oil expressed fungicidal effect on C. albicans biofilm pre-established on the disks fabricated from different brands of silicone. Additionally, the fungicidal effectiveness of the oil against the mature fungal biofilm was dose-dependent.}, } @article {pmid34757102, year = {2022}, author = {Tian, X and Schopf, A and Amaral-Stewart, B and Christensson, M and Morgan-Sagastume, F and St-Pierre, JP and Vincent, S and Mercier, É and Zhang, X and Delatolla, R}, title = {Carrier surface modification for enhanced attachment and growth of anammox biofilm.}, journal = {The Science of the total environment}, volume = {811}, number = {}, pages = {151317}, doi = {10.1016/j.scitotenv.2021.151317}, pmid = {34757102}, issn = {1879-1026}, mesh = {Ammonia ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; *Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; Sewage ; }, abstract = {This study investigates and compares the ammonia removal kinetics, attachment, biofilm development and anammox bacteria enrichment on various surface modified carriers throughout the 163 days of start-up of an MBBR system: virgin, dextran-functionalized carriers, silica-functionalized and pre-seeded denitrifying carriers. Silica-functionalized carriers along with pre-seeded denitrifying carriers induced significant higher kinetics, faster biofilm growth and greater anammox bacteria enrichment during the 64 days of operation compared to non-modified virgin and dextran-functionalized carriers. The elevated anammox bacteria counts along with the elevated kinetics of all carriers measured at day 106 indicated that the completed biofilm growth and biofilm maturation are achieved prior to or at day 106 of start-up. The NH4[+]-N removal rate for virgin, dextran-functionalized, silica-functionalized and pre-seeded denitrifying carriers were achieved 0.684 ± 0.019, 0.608 ± 0.016, 0.634 ± 0.017 and 0.665 ± 0.018 g NH4[+]-N/m[2]/d, respectively, at day 106. The results demonstrate that the silica-functionalized and pre-seeded denitrifying carriers offer advantages during the early stage of start-up while the dextran-functionalized carriers did not reduce the start-up period for anammox biofilm.}, } @article {pmid34756979, year = {2022}, author = {Liu, L and Wang, F and Xu, S and Yan, Z and Ji, M}, title = {Long-term effect of fulvic acid amendment on the anammox biofilm system at 15 ℃: performance, microbial community and metagenomics analysis.}, journal = {Bioresource technology}, volume = {344}, number = {Pt B}, pages = {126234}, doi = {10.1016/j.biortech.2021.126234}, pmid = {34756979}, issn = {1873-2976}, mesh = {Anaerobic Ammonia Oxidation ; Anaerobiosis ; Benzopyrans ; Biofilms ; Bioreactors ; *Metagenomics ; *Microbiota ; Nitrogen ; Oxidation-Reduction ; }, abstract = {The role of fulvic acid (FA) on the anammox system at 15 ℃ was investigated. After operation for 113 days, total inorganic nitrogen removal efficiency in FA amendment reactor achieved to 58.6% on average, higher than that of control group (42.1%). Anammox-related functional genes, i.e., hzo and hzs, also demonstrated higher expression level after introduction of FA. It was observed that Candidatus Kuenenia became more competitive than Candidatus Brocadia with the existence of FA at 15 ℃. Also, co-occurrence analysis showed that FA stimulated the complexity and interactive relationship of microbial communities in the anammox system. Metagenomics analysis revealed that FA introduction stimulated relative abundances of genes in central pathway of tricarboxylic acid cycle such as ACO, IDH, OGDH, SCS, FUM, and MDH. Meanwhile, metabolomics analysis revealed that metabolites related to amino sugar metabolic pathways (glucose 1-phosphate, UDP-D-glucuronate, UDP) and redox reactions (NAD[+] and NADH) improved in the FA amendment reactor.}, } @article {pmid34756515, year = {2021}, author = {Al-Tamimi, A and Alfarhan, A and Rajagopal, R}, title = {Antimicrobial and anti-biofilm activities of polyphenols extracted from different Saudi Arabian date cultivars against human pathogens.}, journal = {Journal of infection and public health}, volume = {14}, number = {12}, pages = {1783-1787}, doi = {10.1016/j.jiph.2021.10.006}, pmid = {34756515}, issn = {1876-035X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; Humans ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; *Polyphenols/pharmacology ; Saudi Arabia ; }, abstract = {BACKGROUND: Microbial diseases have emerged as a serious threat to the healthcare system globally and also in Saudi Arabia; various diseases are associated with higher mortality and increased spreading rates. Dietary sources are often entertained to improve the immune system of the body to fight against these infections. The date fruit (Phoenix dactylifera L) is one such functional food that is less explored for its actual potentials.

METHODS: The polyphenols isolated from the different cultivars of dates in Saudi Arabia (Ajwa, Safawi, Khalas, and Sukkary) was evaluated for their antibacterial, anti-fungal and anti-biofilm forming abilities. The anti-radical properties of the phenolic extract were conducted in terms of the scavenging of diphenyl-1-picrylhydrazyl radical, hydrogen peroxide radicals and ABTS radicals. The anti-inflammatory potential was analyzed in terms of lipoxygenase activity inhibition.

RESULTS: The phenolic compounds of different dates were spectrophotometrically estimated and cultivars such as Ajwa and Sukkary had the highest polyphenol content. It was also noteworthy that they exerted potent antibacterial activities against Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa as estimated by the least minimal inhibitory concentration (MIC) or minimal bactericidal concentration (MBC) values. Besides, these polyphenols reduced the biofilm formation by these bacterial pathogens; it is thus possible that the polyphenols from dates can be a promising antimicrobial agent against various pathogenic strains. Corroborating with these, the polyphenol extracts from different Saudi Arabian dates were found to inhibit the growth of mycelium in strains of Candida albicans and Aspergillus niger. Apart from these, the polyphenol isolates also exhibited significant anti-radical properties against different reactive radical systems.

CONCLUSION: Overall, the efficacy of phenolic compounds extracted from the dried date fruits are not only restricted to the functional food features; instead, these molecules are capable of preventing the growth of microbial pathogens of humans. Hence, it may emerge as potent antibacterial, anti-fungal and anti-biofilm forming candidates.}, } @article {pmid34756121, year = {2022}, author = {Goudarztalejerdi, A and Mohammadzadeh, A and Niazi, K and Mohammad Mirzaei, M}, title = {High Prevalence of Multidrug Resistance and Biofilm-Formation Ability Among Avian Escherichia coli Isolated from Broilers in Iran.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {28}, number = {2}, pages = {244-254}, doi = {10.1089/mdr.2021.0091}, pmid = {34756121}, issn = {1931-8448}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Chickens/*microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/drug effects/*genetics ; Genes, Bacterial ; Iran ; Microbial Sensitivity Tests ; Poultry Diseases/*microbiology ; }, abstract = {The present study was conducted to determine the antimicrobial resistance pattern and biofilm-formation ability in 100 Avian-Pathogenic Escherichia coli (APEC) isolated from colibacillosis-suspected broilers and 100 Avian Fecal E. coli (AFEC) isolates from healthy broilers in Hamedan, Iran. All isolates were screened by polymerase chain reaction for antimicrobial resistance genes, class 1 and 2 integrons, and biofilm-associated genes. Besides, we assessed the possible relationship between biofilm-formation ability antibiotic resistance patterns, genetic background, and the pathogenicity of APEC strains. 81% of APEC and 73% of AFEC isolates showed multidrug resistance (MDR) phenotype; in addition, 45% of the APEC and 21% of the AFEC strains showed biofilm-formation ability. This is the first report of the biofilm formation ability in E. coli isolated from broilers in Iran. The most prevalent antibiotic resistance gene in APEC strains was tetA (68%), followed by sul1 (63%), dfrA1-like (51%), and blaTEM (30%), whereas in AFEC strains, the frequencies of the antibiotic resistance genes were tetA (63%), sul1 (58%), dfrA1-like (49%), and blaTEM (22%). Out of 81 MDR APEC isolates, 53 (65.4%) and 38 (46.91%) isolates were positive for intI1 and intI2 genes, respectively. In the AFEC strains intI1 and intI2 genes were presented in 57 and 33 isolates, respectively. All APEC isolates belonging to phylogenetic groups B1, B2, and C were MDR. The results of the present study indicate that isolates with biofilm-forming ability show more MDR properties and probably have more pathogenicity to broilers.}, } @article {pmid34755784, year = {2021}, author = {Zancan, RF and Ponce, JB and Dionisio, TJ and Oliveira, RC and Silva, RAD and Duque, JA and Duarte, MAH}, title = {Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode.}, journal = {Brazilian dental journal}, volume = {32}, number = {3}, pages = {10-20}, doi = {10.1590/0103-6440202104503}, pmid = {34755784}, issn = {1806-4760}, mesh = {Anti-Bacterial Agents ; Bacteria ; *Biofilms ; Calcium Hydroxide ; Chlorhexidine ; Enterococcus faecalis ; Humans ; *Plankton ; Root Canal Irrigants ; }, abstract = {The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1β, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 β, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.}, } @article {pmid34754505, year = {2021}, author = {He, W and Zhang, Z and Chen, J and Zheng, Y and Xie, Y and Liu, W and Wu, J and Mosselhy, DA}, title = {Evaluation of the anti-biofilm activities of bacterial cellulose-tannic acid-magnesium chloride composites using an in vitro multispecies biofilm model.}, journal = {Regenerative biomaterials}, volume = {8}, number = {6}, pages = {rbab054}, pmid = {34754505}, issn = {2056-3418}, abstract = {Chronic wounds are a serious worldwide problem, which are often accompanied by wound infections. In this study, bacterial cellulose (BC)-based composites introduced with tannic acid (TA) and magnesium chloride (BC-TA-Mg) were fabricated for anti-biofilm activities. The prepared composites' surface properties, mechanical capacity, thermal stability, water absorption and retention property, releasing behavior, anti-biofilm activities and potential cytotoxicity were tested. Results showed that TA and MgCl2 particles closely adhered to the nanofibers of BC membranes, thus increasing surface roughness and hydrophobicity of the membranes. While the introduction of TA and MgCl2 did not influence the transparency of the membranes, making it beneficial for wound inspection. BC-TA and BC-TA-Mg composites displayed increased tensile strength and elongation at break compared to pure BC. Moreover, BC-TA-Mg exhibited higher water absorption and retention capacity than BC and BC-TA, suitable for the absorption of wound exudates. BC-TA-Mg demonstrated controlled release of TA and good inhibitory effect on both singly cultured Staphylococcus aureus and Pseudomonas aeruginosa biofilm and co-cultured biofilm of S. aureus and P. aeruginosa. Furthermore, the cytotoxicity grade of BC-TA-6Mg membrane was eligible based on standard toxicity classifications. These indicated that BC-TA-Mg is potential to be used as wound dressings combating biofilms in chronic wounds.}, } @article {pmid34751916, year = {2022}, author = {Kaviar, VH and Khoshnood, S and Asadollahi, P and Kalani, BS and Maleki, A and Yarahmadi, S and Pakzad, I}, title = {Survey on phenotypic resistance in Enterococcus faecalis: comparison between the expression of biofilm-associated genes in Enterococcus faecalis persister and non-persister cells.}, journal = {Molecular biology reports}, volume = {49}, number = {2}, pages = {971-979}, pmid = {34751916}, issn = {1573-4978}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Biological Variation, Population/genetics ; Enterococcus faecalis/*genetics/*growth & development/metabolism ; Genes, Bacterial/genetics ; Microbial Sensitivity Tests ; Vancomycin/pharmacology ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Phenotypic resistance is considered as a serious therapeutic challenge for which a definitive remedy has not been discovered yet. Biofilm and persister cell formation are two well-studied phenotypic resistance phenomena, leading to the recalcitrance and relapse of different types of chronic infections. The presence of persister cells in biofilm structures seems to be one of the main factors contributing to the relapse of infections and treatment failure. Given the dormant and inert nature of persister cells, they can be easy targets for the immune system factors. Biofilm formation can be a survival strategy for the defenseless persister cells. Thus, this study was aimed to evaluate the expression of biofilm-associated genes in Enterococcus faecalis persister and non-persister cells.

METHODS: Vancomycin susceptibility and biofilm formation ability were investigated among 95 E. faecalis clinical isolates using microtiter broth dilution and microtiter plate assays, respectively. PCR was used to determine the presence of biofilm-related genes (gelE, esp, and agg) among the vancomycin-susceptible, biofilm producer E. faecalis isolates (91 isolates). Minimum bactericidal concentration for biofilms (MBCB) were determined for vancomycin using the MTP assay. Bacterial persister assay was performed using an enzymatic lysis assay. Finally, the expression of biofilm-related genes was compared between the persister and non-persister isolates of E. faecalis using real-time qPCR.

RESULTS: E. faecalis isolates showed a high level of susceptibility (95.8%) to vancomycin (MIC < 1 µg/mL). The gelE, esp, and agg genes were found in 91 (100%), 72 (79.12), and 74 (81.32) of the isolates, respectively. All the E. faecalis isolates were tolerant to vancomycin in the biofilm condition, showing a MBCB of > 2500 µg/mL. Based on the enzymatic lysis assay, only 3 isolates, out of the 91, had the ability to form persister cells. The expression of biofilm-associated genes was higher among the persister compared to non-persister E. faecalis isolates.

CONCLUSIONS: Biofilm-associated persister cells indicated a high vancomycin tolerance compared to non-persister cells. Moreover, persister isolates showed a higher tendency for biofilm formation and a higher expression level of the biofilm-associated genes, compared to non-persister isolates.}, } @article {pmid34751825, year = {2021}, author = {Velmurugan, K and Bhuvanesh, N and Prakash, AF and Maheskumar, V and Vidhya, B and Murugan, S and Kumar, RS and Almansour, AI and Perumal, K and Nandhakumar, R}, title = {Graphene oxide-rhodamine nanocomposite for picomolar detection of chromium(III) by fluorimetry and its biofilm inhibition.}, journal = {Mikrochimica acta}, volume = {188}, number = {12}, pages = {414}, pmid = {34751825}, issn = {1436-5073}, mesh = {Acinetobacter baumannii/drug effects ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Chromium/*chemistry ; Environmental Pollutants/chemistry ; Fluorescence ; Fluorometry/*methods ; Graphite/*chemistry ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Nanocomposites/*chemistry ; Rhodamines/*chemistry ; }, abstract = {Graphene oxide-rhodamine B hydrazide (GO-RhB) nanocomposite was prepared by a simple chemical method and characterized by various spectroscopic and analytical techniques. GO-RhB nanocomposite potentially detects Cr[3+] ion (excitation/emission = 550 nm/572 nm) via fluorescence turn "on-off" approach. This composite showed high binding affinity (10[6] M[-1]) with Cr[3+] and a+ limit of detection (LOD) down to picomolar concentration (LOD = 85.6 pM). As far as we know, this is the first report for the sensing of Cr[3+] ion at picomolar concentration. GO-RhB selectively senses Cr[3+] ion without any interference of other coexisting metal ions. In addition, this composite exhibited the dynamic nature of quenching in the presence of Cr[3+] ion, which is confirmed by the Stern-Volmer plot, fluorescence temperature profiles, and decay time experiments. The GO-RhB nanocomposite-based fluorescent probe was successfully applied to the quantitative detection of Cr[3+] ion in milk sample (linear range = 2 to 10 nM) with better performance than other existing methods. Besides, this GO-RhB composite showed better antibiofilm activity against Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) by using the Congo red agar and tube method.}, } @article {pmid34750645, year = {2021}, author = {Bajire, SK and Jain, S and Johnson, RP and Shastry, RP}, title = {6-Methylcoumarin attenuates quorum sensing and biofilm formation in Pseudomonas aeruginosa PAO1 and its applications on solid surface coatings with polyurethane.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {23}, pages = {8647-8661}, pmid = {34750645}, issn = {1432-0614}, support = {YU/Seed grant/080-2019//Yenepoya (Deemed to be University)/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Caenorhabditis elegans ; Coumarins ; Polyurethanes ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors ; }, abstract = {Quorum sensing mediated biofilm formation has a major role in modern therapeutics due to adherence of cells on the solid surface. Here, we have developed a stable polyurethane blend with a 6-methylcoumarin (6-MC) composite that showed significant antibiofilm activity. The 6-MC was found to prominently inhibit P. aeruginosa PAO1 biofilm formation at 125 μg/ml and was able to inhibit various virulence factors such as pyocyanin, siderophore, exopolysaccharide, elastase and proteases, including motility of the bacteria. In addition, 6-MC was found functionally active in saving the C. elegans from P. aeruginosa PAO1 infection. Moreover, docking studies of different activator proteins correlate well with in vitro and in vivo results. To enhance this biological activity, 6-MC was blended with polyurethane, which also revealed superior antibiofilm activity on plastic and glass surfaces compared to a polyurethane coating. Therefore, the 6-MC could be used to combat P. aeruginosa infection for effective treatment and antibiofilm applications on solid surfaces through polyurethane blending and subsequent film fabrication strategies. KEY POINTS: • 6-Methylcoumarin significantly inhibits P. aeruginosa PAO1 biofilm • 6-MC was found functionally active in saving the C. elegans from PAO1 infection • 6-MC and polyurethane blend showed superior antibiofilm activity.}, } @article {pmid34750463, year = {2021}, author = {Hutchins, C and Sayavedra, L and Diaz, M and Gupta, P and Tissingh, E and Elumogo, C and Nolan, J and Charles, I and Elumogo, N and Narbad, A}, title = {Genomic analysis of a rare recurrent Listeria monocytogenes prosthetic joint infection indicates a protected niche within biofilm on prosthetic materials.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {21864}, pmid = {34750463}, issn = {2045-2322}, support = {BBS/E/F/00044453/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10348/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012490/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/OS/NW/000006/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10355/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; Food Innovation and Health BB/R012512/1 (BBS/E/ F/000PR10346), Newton Fund Joint Centre Award, and BBSRC Institute Strategic Programme Gut Microbes and Health BB/R012490/1 (BBS/E/F/000PR10355 and BBS/E/F/000PR10356)/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10356/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Aged, 80 and over ; Biofilms/growth & development ; Disease Reservoirs/microbiology ; Genome, Bacterial ; Hip Prosthesis/adverse effects/*microbiology ; Host Microbial Interactions/genetics ; Humans ; Listeria monocytogenes/*genetics/isolation & purification/physiology ; Listeriosis/*microbiology ; Mutation Rate ; Polymorphism, Single Nucleotide ; Prosthesis-Related Infections/*microbiology ; Recurrence ; Time Factors ; }, abstract = {Listeria monocytogenes is a rare cause of prosthetic joint infections (PJI). In this study, we describe a case of recurrent L. monocytogenes infections, 39 months apart, following debridement and retention of a prosthetic hip. Despite numerous studies reporting persistent L. monocytogenes in human infections, the genomic and phenotypic changes that clinically relevant strains undergo in the host are poorly understood. Improved knowledge of how PJI occurs is needed to improve the management of prosthetic infections. We used a combination of long- and short-read sequencing to identify any potential genomic differences between two L. monocytogenes isolates that occurred over 39-month incubation in the host. The isolates, QI0054 and QI0055, showed three single nucleotide polymorphisms and three insertions or deletions, suggesting that the recurrent infection was caused by the same strain. To identify potential differences in the capacity for persistence of these isolates, their biofilm-forming ability and potential to colonize prosthesis-relevant materials was investigated both in microtitre plates and on prosthetic material titanium, stainless steel 316 and ultra-high molecular weight polyethylene. Whilst the L. monocytogenes isolate from the most recent infection (QI0055) was able to form higher biofilm in microtitre plates, this did not lead to an increase in biomass on prosthetic joint materials compared to the initial isolate (QI0054). Both clinical isolates were able to form significantly more biofilm on the two metal prosthetic materials than on the ultra-high molecular weight polyethylene, in contrast to reference strain Scott A. Transcriptomics revealed 41 genes overexpressed in biofilm state and 643 in planktonic state. Moreover, genes with mutations were actively expressed in both isolates. We conclude the isolates are derived from the same strain and hypothesize that L. monocytogenes formed biofilm on the prosthetic joint materials, with minimal exposure to stresses, which permitted their survival and growth.}, } @article {pmid34749532, year = {2021}, author = {Tischler, AH and Vanek, ME and Peterson, N and Visick, KL}, title = {Calcium-Responsive Diguanylate Cyclase CasA Drives Cellulose-Dependent Biofilm Formation and Inhibits Motility in Vibrio fischeri.}, journal = {mBio}, volume = {12}, number = {6}, pages = {e0257321}, pmid = {34749532}, issn = {2150-7511}, support = {R35 GM130355/GM/NIGMS NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/enzymology/*metabolism ; Bacterial Proteins/metabolism ; *Biofilms ; Calcium/*metabolism ; Calcium Signaling ; Cellulose/*metabolism ; Cyclic GMP/analogs & derivatives ; Escherichia coli Proteins ; Gene Expression Regulation, Bacterial ; Hawaii ; Phosphorus-Oxygen Lyases/*metabolism ; Transcription Factors/metabolism ; Vibrio cholerae/genetics ; }, abstract = {The marine bacterium Vibrio fischeri colonizes its host, the Hawaiian bobtail squid, in a manner requiring both bacterial biofilm formation and motility. The decision to switch between sessile and motile states is often triggered by environmental signals and regulated by the widespread signaling molecule c-di-GMP. Calcium is an environmental signal previously shown to affect both biofilm formation and motility by V. fischeri. In this study, we investigated the link between calcium and c-di-GMP, determining that calcium increases intracellular c-di-GMP dependent on a specific diguanylate cyclase, calcium-sensing protein A (CasA). CasA is activated by calcium, dependent on residues in an N-terminal sensory domain, and synthesizes c-di-GMP through an enzymatic C-terminal domain. CasA is responsible for calcium-dependent inhibition of motility and activation of cellulose-dependent biofilm formation. Calcium regulates cellulose biofilms at the level of transcription, which also requires the transcription factor VpsR. Finally, the Vibrio cholerae CasA homolog, CdgK, is unable to complement CasA and may be inhibited by calcium. Collectively, these results identify CasA as a calcium-responsive regulator, linking an external signal to internal decisions governing behavior, and shed light on divergence between Vibrio spp. IMPORTANCE Biofilm formation and motility are often critical behaviors for bacteria to colonize a host organism. Vibrio fischeri is the exclusive colonizer of its host's symbiotic organ and requires both biofilm formation and motility to initiate successful colonization, providing a relatively simple model to explore complex behaviors. In this study, we determined how the environmental signal calcium alters bacterial behavior through production of the signaling molecule c-di-GMP. Calcium activates the diguanylate cyclase CasA to synthesize c-di-GMP, resulting in inhibition of motility and activation of cellulose production. These activities depend on residues in CasA's N-terminal sensory domain and C-terminal enzymatic domain. These findings thus identify calcium as a signal recognized by a specific diguanylate cyclase to control key bacterial phenotypes. Of note, CasA activity is seemingly inverse to that of the homologous V. cholerae protein, CdgK, providing insight into evolutionary divergence between closely related species.}, } @article {pmid34749282, year = {2021}, author = {Yi, L and Fan, Q and Wang, Y and Mao, C and Li, J and Jin, M and Zhang, X and Ding, K and Wang, Y}, title = {Evaluation of immune effect of Streptococcus suis biofilm-associated protein PDH.}, journal = {Veterinary microbiology}, volume = {263}, number = {}, pages = {109270}, doi = {10.1016/j.vetmic.2021.109270}, pmid = {34749282}, issn = {1873-2542}, mesh = {Animals ; *Bacterial Proteins/genetics/immunology ; *Biofilms ; Escherichia coli/genetics ; Immunization/veterinary ; Mice ; *Oxidoreductases/genetics/immunology ; *Recombinant Proteins/genetics/immunology ; *Streptococcal Infections/prevention & control/veterinary ; *Streptococcus suis/genetics ; Swine ; Swine Diseases/prevention & control ; Vaccine Development ; }, abstract = {As a zoonotic pathogen, Streptococcus suis(S. suis) takes pigs as the main host and is mainly colonizes in the upper respiratory tract and tonsil of pigs, causing septicemia, endocarditis and meningitis in pigs. Pyruvate dehydrogenase (PDH) is an enzyme that catalyzes the conversion of pyruvate to acetyl-CoA. As an immunogenic membrane-associated protein in S. suis, it has been found to be closely related to the formation of biofilm. In this study, the recombinant PDH (rPDH) of S. suis ZY05719 (serotype 2) was expressed and purified in E. coli by His affinity chromatography. Western blotting analysis showed that there was a strong specific reaction between PDH protein and PDH antiserum. Mice were immunized with recombinant PDH and inactivated bacteria, and the relative survival rates were 70 % and 60 %, respectively. In addition, mice immunized with PDH caused high levels of antibodies and high expression of immune-related genes in the spleen, which significantly protected the liver, brain and spleen from pathological damage. In addition, PDH antiserum could significantly inhibit the growth of S. suis and the formation of S. suis biofilm in vitro. These results further suggest that PDH is a promising candidate for S. suis biofilm-related subunit vaccine.}, } @article {pmid34748523, year = {2021}, author = {Irwin, S and Mackenzie, BW and Matthews, BG and Williams, DL and Cornish, J and Swift, S}, title = {Improve Integration of In Vitro Biofilm Body of Knowledge to Support Clinical Breakthroughs in Surgical Site Infection.}, journal = {Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews}, volume = {5}, number = {11}, pages = {}, pmid = {34748523}, issn = {2474-7661}, mesh = {Animals ; Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Prosthesis-Related Infections/drug therapy ; Surgical Wound Infection/therapy ; }, abstract = {Prosthetics increase the risk of deep surgical site infections in procedures intended to restore function. In orthopaedics, prosthetic joint infections can lead to repetitive surgeries, amputation, or worse. Biofilm formation both in vitro and in vivo involves stages of attachment, accumulation, and maturation. The level of maturation affects susceptibility to antibiotics, the immune system, and the success of surgical interventions. A review of the literature indicates that orthopedic publications are less likely to mention biofilm. We have reviewed animal models of infection to assess in vivo models of prosthetic infection. Although most prosthetic infections seem to originate from local skin microbiota, clinically representative biofilm inocula are unusual. Biofilm-related end points are more widely adopted, but studies rarely include both quantification of adherent microbial burden and imaging of the in vivo biofilm. Failure to differentiate between planktonic and biofilm infections can skew research away from needed chronic disease models. In this review, we address prosthetic joint infections as an important model for chronic biofilm infection research, identify critical requirements for in vivo models of chronic infection, and propose that resistance to the terminology of biofilm research exists within both research and regulation, which could limit progress toward important orthopaedic targets.}, } @article {pmid34746032, year = {2021}, author = {Phuengmaung, P and Panpetch, W and Singkham-In, U and Chatsuwan, T and Chirathaworn, C and Leelahavanichkul, A}, title = {Presence of Candida tropicalis on Staphylococcus epidermidis Biofilms Facilitated Biofilm Production and Candida Dissemination: An Impact of Fungi on Bacterial Biofilms.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {763239}, pmid = {34746032}, issn = {2235-2988}, mesh = {Animals ; Biofilms ; Candida ; Candida albicans ; *Candida tropicalis ; Humans ; Mice ; *Staphylococcus epidermidis ; }, abstract = {While Staphylococcus epidermidis (SE) is a common cause of infections in implanted prostheses and other indwelling devices, partly due to the biofilm formation, Candida tropicalis (CT) is an emerging Candida spp. with a potent biofilm-producing property. Due to the possible coexistence between SE and CT infection in the same patient, characteristics of the polymicrobial biofilms from both organisms might be different from those of the biofilms of each organism. Then, the exploration on biofilms, from SE with or without CT, and an evaluation on l-cysteine (an antibiofilm against both bacteria and fungi) were performed. As such, Candida incubation in preformed SE biofilms (SE > CT) produced higher biofilms than the single- (SE or CT) or mixed-organism (SE + CT) biofilms as determined by crystal violet staining and fluorescent confocal images with z-stack thickness analysis. In parallel, SE > CT biofilms demonstrated higher expression of icaB and icaC than other groups at 20 and 24 h of incubation, suggesting an enhanced matrix polymerization and transportation, respectively. Although organism burdens (culture method) from single-microbial biofilms (SE or CT) were higher than multi-organism biofilms (SE + CT and SE > CT), macrophage cytokine responses (TNF-α and IL-6) against SE > CT biofilms were higher than those in other groups in parallel to the profound biofilms in SE > CT. Additionally, sepsis severity in mice with subcutaneously implanted SE > CT catheters was more severe than in other groups as indicated by mortality rate, fungemia, serum cytokines (TNF-α and IL-6), and kidney and liver injury. Although CT grows upon preformed SE-biofilm production, the biofilm structures interfered during CT morphogenesis leading to the frailty of biofilm structure and resulting in the prominent candidemia. However, l-cysteine incubation together with the organisms in catheters reduced biofilms, microbial burdens, macrophage responses, and sepsis severity. In conclusion, SE > CT biofilms prominently induced biofilm matrix, fungemia, macrophage responses, and sepsis severity, whereas the microbial burdens were lower than in the single-organism biofilms. All biofilms were attenuated by l-cysteine.}, } @article {pmid34745072, year = {2021}, author = {Bobadilla-Fazzini, RA and Poblete-Castro, I}, title = {Biofilm Formation Is Crucial for Efficient Copper Bioleaching From Bornite Under Mesophilic Conditions: Unveiling the Lifestyle and Catalytic Role of Sulfur-Oxidizing Bacteria.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {761997}, pmid = {34745072}, issn = {1664-302X}, abstract = {Biofilm formation within the process of bioleaching of copper sulfides is a relevant aspect of iron- and sulfur-oxidizing acidophilic microorganisms as it represents their lifestyle in the actual heap/dump mining industry. Here, we used biofilm flow cell chambers to establish laminar regimes and compare them with turbulent conditions to evaluate biofilm formation and mineralogic dynamics through QEMSCAN and SEM-EDS during bioleaching of primary copper sulfide minerals at 30°C. We found that laminar regimes triggered the buildup of biofilm using Leptospirillum spp. and Acidithiobacillus thiooxidans (inoculation ratio 3:1) at a cell concentration of 10[6] cells/g mineral on bornite (Cu5FeS4) but not for chalcopyrite (CuFeS2). Conversely, biofilm did not occur on any of the tested minerals under turbulent conditions. Inoculating the bacterial community with ferric iron (Fe[3+]) under shaking conditions resulted in rapid copper recovery from bornite, leaching 40% of the Cu content after 10 days of cultivation. The addition of ferrous iron (Fe[2+]) instead promoted Cu recovery of 30% at day 48, clearly delaying the leaching process. More efficiently, the biofilm-forming laminar regime almost doubled the leached copper amount (54%) after 32 days. In-depth inspection of the microbiologic dynamics showed that bacteria developing biofilm on the surface of bornite corresponded mainly to At. Thiooxidans, while Leptospirillum spp. were detected in planktonic form, highlighting the role of biofilm buildup as a means for the bioleaching of primary sulfides. We finally propose a mechanism for bornite bioleaching during biofilm formation where sulfur regeneration to sulfuric acid by the sulfur-oxidizing microorganisms is crucial to prevent iron precipitation for efficient copper recovery.}, } @article {pmid34745053, year = {2021}, author = {Oliva, A and Stefani, S and Venditti, M and Di Domenico, EG}, title = {Biofilm-Related Infections in Gram-Positive Bacteria and the Potential Role of the Long-Acting Agent Dalbavancin.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {749685}, pmid = {34745053}, issn = {1664-302X}, abstract = {Infections caused by Gram-positive bacteria are a major public health problem due to their increasing resistance to antibiotics. Staphylococcus and Enterococcus species' resistance and pathogenicity are enhanced by their ability to form biofilm. The biofilm lifestyle represents a significant obstacle to treatment because bacterial cells become highly tolerant to a wide range of antimicrobial compounds normally effective against their planktonic forms. Thus, novel therapeutic strategies targeting biofilms are urgently needed. The lipoglycopeptide dalbavancin is a long-acting agent for treating acute bacterial skin and skin structure infections caused by a broad range of Gram-positive pathogens. Recent studies have shown promising activity of dalbavancin against Gram-positive biofilms, including methicillin-resistant S. aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and vancomycin-susceptible enterococci. This review outlines the mechanisms regulating biofilm development in Staphylococcus and Enterococcus species and the clinical impact of biofilm-related infections. In addition, it discusses the clinical implications and potential therapeutic perspectives of the long-acting drug dalbavancin against biofilm-forming Gram-positive pathogens.}, } @article {pmid34743877, year = {2022}, author = {Liu, Y and Zhu, T and Ren, S and Zhao, T and Chai, H and Xu, Y and Peng, L and Liu, Y}, title = {Contribution of nitrification and denitrification to nitrous oxide turnovers in membrane-aerated biofilm reactors (MABR): A model-based evaluation.}, journal = {The Science of the total environment}, volume = {806}, number = {Pt 3}, pages = {151321}, doi = {10.1016/j.scitotenv.2021.151321}, pmid = {34743877}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Nitrification ; *Nitrous Oxide ; }, abstract = {As a novel and sustainable technology, membrane-aerated biofilm reactors (MABR) performing simultaneous nitrification and denitrification face the challenge of undesirable nitrous oxide (N2O) emission. Thereby, a comprehensive analysis of N2O turnover pathways and the affecting parameters in MABR are demanded for N2O mitigation strategies. In this work, a mathematical model describing three N2O turnovers pathways was studied to uncover the underlying mechanisms and the impacts of operational conditions on N2O turnovers in MABR system performing simultaneous nitrification and denitrification. The modeling results demonstrate that higher oxygen surface loading, longer hydraulic retention time (HRT) and lower influent chemical oxygen demand (COD) significantly induce higher N2O production factor (0.18%-3.3%). N2O turnovers are mainly regulated by the hydroxylamine (NH2OH) pathway and heterotrophic bacteria (HB) denitrification, accounting for 76%-87% and 10%-21%, respectively. In contrast, the thicker biofilm (i.e., 400-600 μm) causes lower N2O production factor (<0.13%), due to the shift of N2O turnover pathways to the ammonium oxidizing bacteria (AOB) denitrification pathway (7.1%-9.3%) and HB denitrification (90.7%-92.9%). Meanwhile, the result of in-biofilm N2O conversion rates shows that the NH2OH pathway and HB denitrification become the predominant N2O production pathway at the inner zone (0-160 μm) and the outer zone (290-350 μm) of the biofilm in MABR, respectively. The biofilm thickness at 160-280 μm can thus be regarded as an optimal zone to reduce N2O production in MABR, due to more electrons preferentially used for N2O reduction. The relatively low N2O production factor (<0.5%) together with >80% total nitrogen (TN) removal in MABR can be achieved by controlling the oxygen surface loading (1.821-3.641 g/m[2]/d) and influent COD concentrations (285-500 mg/L) within a certain range.}, } @article {pmid34743650, year = {2021}, author = {Bajaj, JS and Shamsaddini, A and Acharya, C and Fagan, A and Sikaroodi, M and Gavis, E and McGeorge, S and Khoruts, A and Fuchs, M and Sterling, RK and Lee, H and Gillevet, PM}, title = {Multiple bacterial virulence factors focused on adherence and biofilm formation associate with outcomes in cirrhosis.}, journal = {Gut microbes}, volume = {13}, number = {1}, pages = {1993584}, pmid = {34743650}, issn = {1949-0984}, support = {I01 CX001076/CX/CSRD VA/United States ; R01 HS025412/HS/AHRQ HHS/United States ; R21 TR003095/TR/NCATS NIH HHS/United States ; }, mesh = {Adult ; Aged ; Bacteria/genetics ; *Bacterial Adhesion ; Bacterial Physiological Phenomena ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cohort Studies ; Fecal Microbiota Transplantation ; Feces/microbiology ; Female ; Gastrointestinal Microbiome ; Humans ; Liver Cirrhosis/*microbiology/therapy ; Male ; Middle Aged ; Virulence Factors/genetics/*metabolism ; Young Adult ; }, abstract = {BACKGROUND & AIMS: Altered gut microbiota is associated with poor outcomes in cirrhosis, including infections and hepatic encephalopathy (HE). However, the role of bacterial virulence factors (VFs) is unclear. Aim: Define association of VFs with cirrhosis severity and infections, their linkage with outcomes, and impact of fecal microbiota transplant (FMT).

METHODS: VF abundances were determined using metagenomic analysis in stools from controls and cirrhosis patients (compensated, HE-only, ascites-only, both and infected). Patients were followed for 90-day hospitalizations and 1-year death. Stool samples collected before/after a placebo-controlled FMT trial were also analyzed. Bacterial species and VFs for all species and selected pathogens (Escherichia, Klebsiella, Pseudomonas, Staphylococcus, Streptococcus, and Enterococcus spp) were compared between groups. Multi-variable analyses were performed for clinical biomarkers and VFs for outcome prediction. Changes in VFs pre/post-FMT and post-FMT/placebo were analyzed. Results: We included 233 subjects (40 controls, 43 compensated, 30 HE-only, 20 ascites-only, 70 both, and 30 infected). Decompensated patients, especially those with infections, had higher VFs coding for siderophores, biofilms, and adhesion factors versus the rest. Biofilm and adhesion VFs from Enterobacteriaceae and Enterococcus spp associated with death and hospitalizations independent of clinical factors regardless of when all VFs or selected pathogens were analyzed. FMT was associated with reduced VF post-FMT versus pre-FMT and post-placebo groups.

CONCLUSIONS: Virulence factors from multiple species focused on adhesion and biofilms increased with decompensation and infections, associated with death and hospitalizations independent of clinical factors, and were attenuated with FMT. Strategies focused on targeting multiple virulence factors could potentially impact outcomes in cirrhosis.

PRESENTATIONS: Portions of this manuscript were an oral presentation in the virtual International Liver Congress 2021.

ABBREVIATIONS: VF: virulence factors, HE: hepatic encephalopathy, FMT: Fecal microbiota transplant, PPI: proton pump inhibitors, LPS: lipopolysaccharides, VFDB: Virulence factor database, OTU: operational taxonomic units, SBP: spontaneous bacterial peritonitis, UTI: urinary tract infections, MRSA: methicillin resistant Staphylococcus aureus, VRE: vancomycin-resistant Enterococcus, MAAsLin2: Microbiome Multivariable Associations with Linear Models, LPS: lipopolysaccharides, AKI: acute kidney injury.}, } @article {pmid34742981, year = {2022}, author = {Yang, Y and Zhuang, LL and Yang, T and Zhang, J}, title = {Recognition of key factors on attached microalgae growth from the internal sight of biofilm.}, journal = {The Science of the total environment}, volume = {811}, number = {}, pages = {151417}, doi = {10.1016/j.scitotenv.2021.151417}, pmid = {34742981}, issn = {1879-1026}, mesh = {Biofilms ; Biomass ; *Microalgae ; Nitrogen/analysis ; Wastewater ; }, abstract = {Microalgae cultivation with wastewater could realize the advanced water treatment and pollutant conversion to biomass. Attached microalgae cultivation mode, that can avoid the high-cost and energy-extensive consumption process of biomass recovery from water in suspended cultivation mode, is getting increasing attention. During the attached cultivation, light and nutrient concentration in the internal biofilm, play a direct and crucial role in regulating the growth of microalgae. Hence, the distribution of light and nutrients at different depths of biofilm were first explored in this study together with the change rules of its internal distribution under different external nutrient levels. It demonstrated that the gross growth rate was enhanced by increasing the external nutrient level. Seen from the internal sight of biofilm, the internal nutrient level had a positive response to the external nutrient change. Nutrients (especially nitrogen) distributed homogeneously through the biofilm, and no serious nutrient starvation occurred at the surface layer of biofilm. Photosynthesis rate linearly decreased along the depth of microalgae biofilm (10-120 μm). In conclusion, light, rather than nutrient, would be the key influencing factor on attached microalgae growth. How to optimize the internal light distribution would determine the wastewater purification efficiency based on attached microalgae cultivation.}, } @article {pmid34742959, year = {2022}, author = {Li, Y and Xiang, T and Liang, H and Wang, P and Gao, D}, title = {Achieving rapid mainstream deammonification through inoculating long-term refrigerated sidestream sludge in plug-flow fixed-bed biofilm reactor.}, journal = {The Science of the total environment}, volume = {806}, number = {Pt 4}, pages = {151415}, doi = {10.1016/j.scitotenv.2021.151415}, pmid = {34742959}, issn = {1879-1026}, mesh = {*Ammonium Compounds ; Biofilms ; Bioreactors ; Nitrogen ; Oxidation-Reduction ; *Sewage ; }, abstract = {The start-up of a stable mainstream deammonification requires sufficient anaerobic ammonia-oxidizing bacteria (AnAOB). This study used a plug-flow fixed-bed reactor (PFBR) to verify the feasibility of establishing the mainstream deammonification system by inoculating the sidestream sludge after long-term refrigeration. A rapid resuscitation of the mainstream deammonification system was accomplished by controlling the front-end aeration rate of the PFBR. Results showed that the system was rapidly resuscitated in 44 days eventually with the nitrogen removal rate and nitrogen removal efficiency of 0.1 kg N·(m[3]·d)[-1] and 79.1%, respectively. Also, the efficient performance was secured by the proportionate approaching equilibrium of AnAOB and ammonia-oxidizing bacteria (AOB) activity of 2.35 ± 0.40 and 2.60 ± 0.29 mg N·(g VSS·h)[-1], respectively. In addition, Pearson correlation analysis revealed that AnAOB abundance (detected Candidatus Kuenenia) negatively correlated with the AOB (mainly Nitrosomonas)/AnAOB abundance ratio, while correlated positively with the residual ammonium concentration of a region. Furthermore, long-term refrigeration probably reduced the cross-feed relationship between AnAOB and other symbiotic organisms (Armatimonadetes and Chloroflexi) to maintain the basic metabolism. Meanwhile, extracellular polymeric substances produced by other genera (order Xanthomonadales and Pseudomonadales) decreased the mass transfer, protecting AnAOB from unfavorable conditions, thereby facilitating high AnAOB abundance during refrigeration. Thus, this study provides a promising perspective towards the practical applications of mainstream process.}, } @article {pmid34742000, year = {2022}, author = {Gong, M and Zhang, R and Qi, J and Wang, J and Liu, Q and Zhou, H and Song, Y and Song, X and Mei, Y}, title = {In vitro evaluation of the antibacterial effect of colloidal bismuth subcitrate on Porphyromonas gingivalis and its biofilm.}, journal = {Archives of oral biology}, volume = {133}, number = {}, pages = {105300}, doi = {10.1016/j.archoralbio.2021.105300}, pmid = {34742000}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Microbial Sensitivity Tests ; Organometallic Compounds ; *Porphyromonas gingivalis ; }, abstract = {OBJECTIVE: To investigate the antibacterial and anti-biofilm effects of colloidal bismuth subcitrate (CBS) on Porphyromonas gingivalis (P. gingivalis) in its planktonic and biofilm forms and also compare it with that of 0.2% chlorhexidine (CHX).

DESIGN: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CBS were determined by the microdilution method; the bacteriostatic rate of CBS was determined by the MTT assay; the effect of CBS on the membrane integrity of P. gingivalis was investigated by the flow cytometric methods. The effects of CBS on the biomass and bacterial activity of biofilm were investigated. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to investigate the activity and structure of biofilms.

RESULTS: The MIC and MBC values were 18.75 µg/mL and 37.5 µg/mL. CBS could damage the cell membrane of P. gingivalis. CBS effectively inhibited biofilm formation and promoted dissociation at higher concentrations of 37.5 µg/mL and 75 µg/mL, respectively. The results also indicated an altered biofilm structure and reduced biofilm thickness and bacterial aggregation.

CONCLUSIONS: CBS affected the metabolic and physiological processes of P. gingivalis, inhibited the formation of biofilm, and disrupted the mature biofilm.}, } @article {pmid34741647, year = {2022}, author = {Rosca, AS and Castro, J and França, Â and Vaneechoutte, M and Cerca, N}, title = {Gardnerella Vaginalis Dominates Multi-Species Biofilms in both Pre-Conditioned and Competitive In Vitro Biofilm Formation Models.}, journal = {Microbial ecology}, volume = {84}, number = {4}, pages = {1278-1287}, pmid = {34741647}, issn = {1432-184X}, mesh = {Humans ; Female ; *Gardnerella vaginalis/genetics ; In Situ Hybridization, Fluorescence ; *Vaginosis, Bacterial/microbiology ; Biofilms ; Vagina/microbiology ; Bacteria ; }, abstract = {Bacterial vaginosis (BV) is one of the most common bacterial vaginal infections worldwide. Despite its high prevalence, BV etiology is still unknown. Nevertheless, a hallmark of BV is the presence of a highly structured polymicrobial biofilm on the vaginal epithelium, formed primarily by Gardnerella spp. and other anaerobic species, of which co-colonization with Fannyhessea vaginae is considered an important diagnostic marker. We previously developed an in vitro biofilm model wherein Gardnerella was first allowed to establish an early biofilm that served as a scaffold for other species to adhere to. To better understand ecological interactions between BV-associated bacteria, we compared triple-species biofilms formed using two distinct models: a pre-conditioned (wherein Gardnerella vaginalis formed the early biofilm) model and a competitive (wherein all three bacteria were co-incubated together) model. Interestingly, synergistic growth interactions were more significant in the competitive model. Furthermore, the biofilm structure and species-specific distribution, as assessed by confocal laser scanning microscopy and using peptide nucleic acid fluorescence in situ hybridization method, revealed two very different triple-species morphotypes, suggesting that different interactions occur in the different models. Interestingly, independent of the model or triple-species consortium tested, we observed that G. vaginalis represented most of the biofilm bacterial composition, further highlighting the relevance of this taxon in BV.}, } @article {pmid34741571, year = {2022}, author = {Jerez-Olate, C and Araya, N and Alcántara, R and Luengo, L and Bello-Toledo, H and González-Rocha, G and Sánchez-Sanhueza, G}, title = {In vitro antibacterial activity of endodontic bioceramic materials against dual and multispecies aerobic-anaerobic biofilm models.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {48}, number = {3}, pages = {465-472}, doi = {10.1111/aej.12587}, pmid = {34741571}, issn = {1747-4477}, mesh = {Materials Testing ; *Silicates/pharmacology ; Calcium Compounds/pharmacology ; *Root Canal Filling Materials/pharmacology ; Silicate Cement ; Anti-Bacterial Agents/pharmacology ; Plankton ; }, abstract = {The aim of this in vitro study was to evaluate the antibacterial activity of calcium silicate repair cements and sealers against a dual-species planktonic aerobic model with different aging times and the ability to inhibit the formation of a mature 21-day-old multispecies anaerobic biofilm. The antibacterial activity of ProRoot MTA, MTA Angelus, Biodentine, BioRoot RCS and TotalFill BC sealer against a dual-species aerobic planktonic model, as well as measuring how materials were affected by aging, was evaluated using the Modified Direct Contact Test. Subsequently, the ability to inhibit the formation of a mature multispecies anaerobic biofilm was evaluated using scanning electron microscopy complemented with confocal laser scanning microscopy. Biodentine and BioRoot RCS had higher antibacterial action, and Biodentine was able to maintain its antibacterial action after a prolonged aging period in vitro. Calcium silicate repair cement MTA ProRoot and Biodentine had higher antibiofilm action.}, } @article {pmid34741374, year = {2022}, author = {El Aichar, F and Muras, A and Parga, A and Otero, A and Nateche, F}, title = {Quorum quenching and anti-biofilm activities of halotolerant Bacillus strains isolated in different environments in Algeria.}, journal = {Journal of applied microbiology}, volume = {132}, number = {3}, pages = {1825-1839}, doi = {10.1111/jam.15355}, pmid = {34741374}, issn = {1365-2672}, support = {PRFU 2018-2022 grant no. D01N01UN160420180012//Direction Générale de la Recherche Scientifique et du Développement Technologique/ ; //General Direction of Higher Education and Training (DGEFS)/ ; //Ministry of Higher Education and Scientific Research (MHESR)/ ; //Universidade de Santiago de Compostela/ ; }, mesh = {Algeria ; *Bacillus ; *Bacillus thuringiensis ; Biofilms ; Quorum Sensing ; }, abstract = {AIMS: The current study aimed to screen Bacillus strains with wide-spectrum quorum quenching (QQ) activity against N-acyl-l-homoserine lactones (AHLs), helpful in controlling virulence traits in Gram-negatives, including biofilm formation and also with anti-biofilm activity against Gram-positives.

METHODS AND RESULTS: A total of 94 halotolerant strains of Bacillus isolated from soil and salt-lake sediment samples in Algeria were examined for the presence of QQ activity against AHLs, the presence of the aiiA gene, encoding an AHL lactonase enzyme typical of Bacillus spp., antimicrobial and anti-biofilm activities against Pseudomonas aeruginosa and Streptococcus mutans. Of all strains of Bacillus spp. isolated, 48.9% showed antibacterial activity. In addition, 40% of these isolates showed a positive QQ activity against long-chain AHLs, of which seven strains presented the aiiA gene. Among the species with broad-spectrum QQ activity, the cell extract of Bacillus thuringiensis DZ16 showed antibiofilm activity against P. aeruginosa PAO1, reducing 60% using the Amsterdam active attachment (AAA) biofilm cultivation model. In addition, the cell extract of B. subtilis DZ17, also presenting a broad-spectrum QQ activity, significantly reduced Strep. mutans ATCC 25175 biofilm formations by 63% and 53% in the xCELLigence and the AAA model, respectively, without affecting growth. Strain DZ17 is of particular interest due to its explicit halophilic nature because it can thrive at salinities in the range of 6%-30%.

CONCLUSIONS: B. thuringiensis DZ16 and B. subtilis DZ17 strains have interesting antibacterial, QQ, and anti-biofilm activities. The high range of salinities accepted by these strains increases their biotechnological potential. This may open up their use as probiotics, the treatment and prevention of conventional and emerging infectious diseases.

The use of safe, economical and effective probiotics is limited to control the infections related to multi-resistant bacteria. In our study, we provide two promising agents with QQ, anti-biofilm and antibacterial activities.}, } @article {pmid34740650, year = {2022}, author = {Sturm, MT and Schuhen, K and Horn, H}, title = {Method for rapid biofilm cultivation on microplastics and investigation of its effect on the agglomeration and removal of microplastics using organosilanes.}, journal = {The Science of the total environment}, volume = {806}, number = {Pt 4}, pages = {151388}, doi = {10.1016/j.scitotenv.2021.151388}, pmid = {34740650}, issn = {1879-1026}, mesh = {Biofilms ; Environmental Monitoring ; Microplastics ; *Organosilicon Compounds ; Plastics ; Spectroscopy, Fourier Transform Infrared ; *Water Pollutants, Chemical/analysis ; }, abstract = {Since microplastics were recognized as a global environmental problem in the early 2000s, research began on possible solutions such as the removal of microplastics from waters. A novel and promising approach for this purpose is microplastics agglomeration-fixation using organosilanes. In this study, it is investigated how biofilm coverage of microplastics affects this process. The biofilm was grown on the microplastics by cultivating it for one week in a packed bed column operated with biologically treated municipal wastewater enriched with glucose. The biofilm was characterized using confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and Fourier-Transform infrared spectroscopy (FT-IR). The results show a partial coverage of the microplastics with attached bacteria and extracellular polymeric substances (EPS) after 7 days of incubation. Comparing five polymer types (polyethylene, polypropylene, polyamide, polyester, and polyvinyl chloride) and three organosilanes, the biofilm coverage caused a reduced removal efficiency for all combinations tested as it changes the surface chemistry of the microplastics and therefore the interaction with the organosilanes tested in this study. Treatment of biofilm covered microplastic with ultrasound partly recovers the removal. However, the results underline the importance of simulated environmental exposure when performing experiments for microplastic removal.}, } @article {pmid34740626, year = {2022}, author = {Al-Khattaf, FS and Al-Ansari, MM and Maruthamuthu, MK and Dyona, L and Agastian, P}, title = {Polyhydroxybutyrate degradation by biocatalyst of municipal sludge water and degradation efficacy in sequencing batch biofilm reactor.}, journal = {Environmental research}, volume = {204}, number = {Pt C}, pages = {112336}, doi = {10.1016/j.envres.2021.112336}, pmid = {34740626}, issn = {1096-0953}, mesh = {Biodegradation, Environmental ; Biofilms ; Carboxylic Ester Hydrolases/metabolism ; *Sewage ; *Water ; }, abstract = {The main aim of the study was to degrade poly-β-hydroxybutyrate (P(3HB)) in the sequencing batch biofilm reactor (SBBR) using biocatalyst. Enrichment method was used for the isolation of P(3HB) degrading bacteria. These bacterial strains were isolated from the wastewater sludge sample treated with P(3HB) sheets. A total of 75 bacteria were isolated after 60 days of incubation. The zone of clearance varied between 12 ± 1 mm and 19 ± 2 mm. Two bacterial strains (Nitrobacter vulgaris SW1 and Pseudomonas aeruginosa KS10) showed rapid PHB degradation activity on agar plates. Plate screening experiments confirmed PHB degrading ability of P. aeruginosa KS10 and N. vulgaris SW1. Biodegrading potential improved after 72 h fermentation period. The bacteria produced depolymerase and enzyme activity was maximum after 72 h. The sequencing batch biofilm reactor (SBBR) co-cultured with N. vulgaris SW1 and P. aeruginosa KS10 was operated to remove PHB from the wastewater. Biofilm in the reactor degraded PHB and the production of polyhydroxybutyrate depolymerase influenced on PHB degradation. Polyhydroxybutyrate degradation improved continuously and maximum degradation (95.6%) was achieved after 8 days. The degradation of biopolymers help to reduce environmental pollution associated with the petroleum based polymers.}, } @article {pmid34739965, year = {2021}, author = {Pan, Y and Subhadra, B and Sandal, I and Dickerman, A and Inzana, TJ}, title = {The role of uspE in virulence and biofilm formation by Histophilus somni.}, journal = {Veterinary microbiology}, volume = {263}, number = {}, pages = {109267}, doi = {10.1016/j.vetmic.2021.109267}, pmid = {34739965}, issn = {1873-2542}, mesh = {Animals ; *Biofilms ; *Haemophilus Infections/microbiology ; *Haemophilus somnus/genetics/pathogenicity ; Heat-Shock Proteins/genetics/metabolism ; Mice ; Mutation ; *Virulence/genetics ; }, abstract = {UspE is a global regulator in Escherichia coli. To study the function of Histophilus somni uspE, strain 2336::TnuspE was identified from a bank of mutants generated with EZ::Tn5™ Tnp Transposome™ that were biofilm deficient. The 2336::TnuspE mutant was highly attenuated in mice, the electrophoretic profile of its lipooligosaccharide (LOS) indicated the LOS was truncated, and the mutant was significantly more serum-sensitive compared to the wildtype strain. In addition to forming a deficient biofilm, exopolysaccharide (EPS) production was also compromised, but the electrophoretic profile of outer membrane proteins was not altered. RNA sequence analysis revealed that the transcription levels of some stress response chaperones, transport proteins, and a large number of ribosomal protein genes in 2336::TnuspE were significantly differentially regulated compared to strain 2336. Therefore, uspE may differentially function in direct and indirect expression of H. somni genes, but its attenuation may be linked to poor biofilm formation and rapid clearance of the bacteria resulting from a compromised LOS structure. Our results support that uspE is a global stress regulatory gene in H. somni.}, } @article {pmid34737774, year = {2021}, author = {Martin, C and Purevdorj-Gage, L and Li, W and Shary, TJ and Yang, B and Murphy, RJ and Wu, CD}, title = {In Vitro Biofilm Formation on Aryl Ketone Polymer (AKP), A New Denture Material, Compared with That on Three Traditional Dental Denture Materials.}, journal = {International journal of dentistry}, volume = {2021}, number = {}, pages = {4713510}, pmid = {34737774}, issn = {1687-8728}, abstract = {Control of denture plaque biofilms is a practical approach to preventing persistent oral infections such as denture stomatitis. Objectives. This study compared in vitro biofilm attachment and growth on a new denture material, Ultaire® AKP, with that on traditional denture materials including cobalt chrome (CoCr), polymethyl methacrylate (PMMA), and polyoxymethylene (POM). Methods. Microbial biofilms were grown with cultures of Candida albicans, Streptococcus mutans UA159, or a mixed Streptococcus spp. (S. mutans 700610/Streptococcus sanguinis BAA-1455) for 6 hours in a static protocol or 24 hours in a dynamic protocol for each material. Adherent biofilm cells were removed, and viable colony-forming units (CFUs) were enumerated. Confocal microscopy of the 24-hour Streptococcus spp. biofilms was used to determine biofilm mass and roughness coefficients. Results. The rank order of C. albicans attachment after 6 hours was CoCr > PMMA [∗] > Ultaire® AKP [∗] ([∗] vs CoCr, p ≤ 0.05), and that for 24-hour biofilm growth was CoCr > Ultaire® AKP [∗] > PMMA [∗] ([∗] vs CoCr, p ≤ 0.05). The rank order of S. mutans biofilm attachment was CoCr > POM > Ultaire® AKP [∗] > PMMA [∗] ([∗] vs CoCr, p ≤ 0.05), and that for the 24-hour Streptococcus spp. biofilm growth was POM > Ultaire® AKP > PMMA > CoCr [∗] ([∗] vs POM, p ≤ 0.05). Confocal images revealed structural differences in Streptococcus spp. biofilms on CoCr compared with the other test materials. Significantly lower roughness coefficients of Streptococcus spp. biofilms on Ultaire® AKP were noted, suggesting that these biofilms were less differentiated. Ultaire® AKP promoted significantly less C. albicans and S. mutans biofilm attachment than CoCr at 6 hours and C. albicans growth at 24 hours. Streptococcus spp. biofilms on Ultaire® AKP were less differentiated than those on other test materials. Conclusion. In addition to its material strength, Ultaire® AKP represents an attractive option for denture material in removable partial dentures.}, } @article {pmid34737361, year = {2021}, author = {Shein, AMS and Wannigama, DL and Higgins, PG and Hurst, C and Abe, S and Hongsing, P and Chantaravisoot, N and Saethang, T and Luk-In, S and Liao, T and Nilgate, S and Rirerm, U and Kueakulpattana, N and Laowansiri, M and Srisakul, S and Muhummudaree, N and Techawiwattanaboon, T and Gan, L and Xu, C and Kupwiwat, R and Phattharapornjaroen, P and Rojanathanes, R and Leelahavanichkul, A and Chatsuwan, T}, title = {Novel colistin-EDTA combination for successful eradication of colistin-resistant Klebsiella pneumoniae catheter-related biofilm infections.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {21676}, pmid = {34737361}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/therapeutic use ; Biofilms/drug effects ; Catheter-Related Infections/drug therapy ; Catheters/microbiology ; Colistin/metabolism/*therapeutic use ; Drug Combinations ; Drug Resistance, Bacterial/drug effects ; Edetic Acid/*therapeutic use ; Female ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/*drug effects/pathogenicity ; Mice ; Mice, Inbred C57BL ; Microbial Sensitivity Tests ; Virulence ; }, abstract = {Development of an effective therapy to overcome colistin resistance in Klebsiella pneumoniae, a common pathogen causing catheter-related biofilm infections in vascular catheters, has become a serious therapeutic challenge that must be addressed urgently. Although colistin and EDTA have successful roles for eradicating biofilms, no in vitro and in vivo studies have investigated their efficacy in catheter-related biofilm infections of colistin-resistant K. pneumoniae. In this study, colistin resistance was significantly reversed in both planktonic and mature biofilms of colistin-resistant K. pneumoniae by a combination of colistin (0.25-1 µg/ml) with EDTA (12 mg/ml). This novel colistin-EDTA combination was also demonstrated to have potent efficacy in eradicating colistin-resistant K. pneumoniae catheter-related biofilm infections, and eliminating the risk of recurrence in vivo. Furthermore, this study revealed significant therapeutic efficacy of colistin-EDTA combination in reducing bacterial load in internal organs, lowering serum creatinine, and protecting treated mice from mortality. Altered in vivo expression of different virulence genes indicate bacterial adaptive responses to survive in hostile environments under different treatments. According to these data discovered in this study, a novel colistin-EDTA combination provides favorable efficacy and safety for successful eradication of colistin-resistant K. pneumonia catheter-related biofilm infections.}, } @article {pmid34737054, year = {2022}, author = {Wu, ZY and Xu, J and Wu, L and Ni, BJ}, title = {Three-dimensional biofilm electrode reactors (3D-BERs) for wastewater treatment.}, journal = {Bioresource technology}, volume = {344}, number = {Pt B}, pages = {126274}, doi = {10.1016/j.biortech.2021.126274}, pmid = {34737054}, issn = {1873-2976}, mesh = {Biofilms ; Electrodes ; Wastewater ; *Water Purification ; }, abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) are highly efficient in refractory wastewater treatment. In comparison to conventional bio-electrochemical systems, the filled particle electrodes act as both electrodes and microbial carriers in 3D-BERs. This article reviews the conception and basic mechanisms of 3D-BERs, as well as their current development. The advantages of 3D-BERs are illustrated with an emphasis on the synergy of electricity and microorganisms. Electrode materials utilized in 3D-BERs are systematically summarized, especially the critical particle electrodes. The configurations of 3D-BERs and their integration with wastewater treatment reactors are introduced. Operational parameters and the adaptation of 3D-BERs to varieties of wastewater are discussed. The prospects and challenges of 3D-BERs for wastewater treatment are then presented, and the future research directions are proposed. We believe that this timely review will help to attract more attentions on 3D-BERs investigation, thus promoting the potential application of 3D-BERs in wastewater treatment.}, } @article {pmid34737049, year = {2022}, author = {Liu, W and Hao, S and Ma, B and Zhang, S and Li, J}, title = {In-situ fermentation coupling with partial-denitrification/anammox process for enhanced nitrogen removal in an integrated three-stage anoxic/oxic (A/O) biofilm reactor treating low COD/N real wastewater.}, journal = {Bioresource technology}, volume = {344}, number = {Pt B}, pages = {126267}, doi = {10.1016/j.biortech.2021.126267}, pmid = {34737049}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Biofilms ; Bioreactors ; Denitrification ; Fermentation ; Nitrogen ; Oxidation-Reduction ; Sewage ; *Wastewater ; }, abstract = {Mainstream partial-denitrification with anammox (PD-anammox) process faced the challenge of complex organics involved in real sewage. Herein, PD-anammox coupled with in-situ fermentation was successfully achieved in a full biofilm system formed by three-stage anoxic/oxic reactor to treat real wastewater with low COD/N of 3.6. The total nitrogen (TN) removal efficiency was enhanced to 78.4% ± 3.6% with average TN and ammonium concentrations in effluent of 10.6 and 0.5 mg N/L, respectively. Batch tests confirmed that partial-denitrification was the major nitrite provider for anammox in the anoxic biofilm, while in-situ fermentation could decompose the complex organics to readily-biodegradable organics for full- or partial-denitrification. Additionally, a significant anammox bacteria (Candidatus Brocadia) population was detected in the second (3.53%) and third (4.46%) anoxic zones, while denitrifiers and fermentative bacteria were mainly enriched in the first anoxic zone. This study presents a feasible approach for PD-anammox process in practical application under mainstream condition.}, } @article {pmid34736409, year = {2021}, author = {Alves, JA and Previato-Mello, M and Barroso, KCM and Koide, T and da Silva Neto, JF}, title = {The MarR family regulator OsbR controls oxidative stress response, anaerobic nitrate respiration, and biofilm formation in Chromobacterium violaceum.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {304}, pmid = {34736409}, issn = {1471-2180}, mesh = {Anaerobiosis ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Chromobacterium/genetics/growth & development/*metabolism ; *Gene Expression Regulation, Bacterial ; Nitrates/*metabolism ; Nitrites/metabolism ; *Oxidative Stress ; Transcription Factors/genetics/*metabolism ; }, abstract = {BACKGROUND: Chromobacterium violaceum is an environmental opportunistic pathogen that causes rare but deadly infections in humans. The transcriptional regulators that C. violaceum uses to sense and respond to environmental cues remain largely unknown.

RESULTS: Here, we described a novel transcriptional regulator in C. violaceum belonging to the MarR family that we named OsbR (oxidative stress response and biofilm formation regulator). Transcriptome profiling by DNA microarray using strains with deletion or overexpression of osbR showed that OsbR exerts a global regulatory role in C. violaceum, regulating genes involved in oxidative stress response, nitrate reduction, biofilm formation, and several metabolic pathways. EMSA assays showed that OsbR binds to the promoter regions of several OsbR-regulated genes, and the in vitro DNA binding activity was inhibited by oxidants. We demonstrated that the overexpression of osbR caused activation of ohrA even in the presence of the repressor OhrR, which resulted in improved growth under organic hydroperoxide treatment, as seem by growth curve assays. We showed that the proper regulation of the nar genes by OsbR ensures optimal growth of C. violaceum under anaerobic conditions by tuning the reduction of nitrate to nitrite. Finally, the osbR overexpressing strain showed a reduction in biofilm formation, and this phenotype correlated with the OsbR-mediated repression of two gene clusters encoding putative adhesins.

CONCLUSIONS: Together, our data indicated that OsbR is a MarR-type regulator that controls the expression of a large number of genes in C. violaceum, thereby contributing to oxidative stress defense (ohrA/ohrR), anaerobic respiration (narK1K2 and narGHJI), and biofilm formation (putative RTX adhesins).}, } @article {pmid34735796, year = {2021}, author = {Buzzo, JR and Devaraj, A and Gloag, ES and Jurcisek, JA and Robledo-Avila, F and Kesler, T and Wilbanks, K and Mashburn-Warren, L and Balu, S and Wickham, J and Novotny, LA and Stoodley, P and Bakaletz, LO and Goodman, SD}, title = {Z-form extracellular DNA is a structural component of the bacterial biofilm matrix.}, journal = {Cell}, volume = {184}, number = {23}, pages = {5740-5758.e17}, pmid = {34735796}, issn = {1097-4172}, support = {R01 AI155501/AI/NIAID NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Antibody Specificity ; Bacteria/*genetics ; Bacterial Proteins/metabolism ; *Biofilms ; Cell Line ; Chinchilla ; DNA, Bacterial/*chemistry ; DNA, Cruciform ; Deoxyribonucleases/metabolism ; Extracellular Matrix/*metabolism ; Extracellular Space/*chemistry ; Extracellular Traps/metabolism ; Humans ; Tetradecanoylphorbol Acetate/pharmacology ; }, abstract = {Biofilms are community architectures adopted by bacteria inclusive of a self-formed extracellular matrix that protects resident bacteria from diverse environmental stresses and, in many species, incorporates extracellular DNA (eDNA) and DNABII proteins for structural integrity throughout biofilm development. Here, we present evidence that this eDNA-based architecture relies on the rare Z-form. Z-form DNA accumulates as biofilms mature and, through stabilization by the DNABII proteins, confers structural integrity to the biofilm matrix. Indeed, substances known to drive B-DNA into Z-DNA promoted biofilm formation whereas those that drive Z-DNA into B-DNA disrupted extant biofilms. Importantly, we demonstrated that the universal bacterial DNABII family of proteins stabilizes both bacterial- and host-eDNA in the Z-form in situ. A model is proposed that incorporates the role of Z-DNA in biofilm pathogenesis, innate immune response, and immune evasion.}, } @article {pmid34735709, year = {2022}, author = {do Canto Canabarro, M and Meneghetti, KL and Geimba, MP and Corção, G}, title = {Biofilm formation and antibiotic susceptibility of Staphylococcus and Bacillus species isolated from human allogeneic skin.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {53}, number = {1}, pages = {153-160}, pmid = {34735709}, issn = {1678-4405}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacillus ; Biofilms ; *Hematopoietic Stem Cell Transplantation ; Humans ; Microbial Sensitivity Tests ; Staphylococcus ; }, abstract = {Human skin banks around the world face a serious problem with the high number of allogeneic skins that are discarded and cannot be used for grafting due to persistent bacterial contamination even after antibiotic treatment. The biofilm formation capacity of these microorganisms may contribute to the antibiotic tolerance; however, this is not yet widely discussed in the literature. Thisstudy analyzed bacterial strains isolated from allogeneic human skin samples,which were obtained from a hospital skin bank that had already been discardeddue to microbial contamination. Biofilm formation and susceptibility topenicillin, tetracycline, and gentamicin were evaluated by crystal violetbiomass quantification and determination of the minimum inhibitoryconcentration (MIC), minimum biofilm inhibitory concentration (MBIC), andminimum biofilm eradication concentration (MBEC) by the broth microdilutionmethod with resazurin dye. A total of 216 bacterial strains were evaluated, and204 (94.45%) of them were classified as biofilm formers with varying degrees ofadhesion. MBICs were at least 512 times higher than MICs, and MBECs were atleast 512 times higher than MBICs. Thus, the presence of biofilm in allogeneicskin likely contributes to the inefficiency of the applied treatments as antibiotictolerance is known to be much higher when bacteria are in the biofilmconformation. Thus, antibiotic treatment protocols in skin banks shouldconsider biofilm formation and should include compounds with antibiofilmaction.}, } @article {pmid34734624, year = {2021}, author = {Nain, A and Huang, HH and Chevrier, DM and Tseng, YT and Sangili, A and Lin, YF and Huang, YF and Chang, L and Chang, FC and Huang, CC and Tseng, FG and Chang, HT}, title = {Catalytic and photoresponsive BiZ/CuxS heterojunctions with surface vacancies for the treatment of multidrug-resistant clinical biofilm-associated infections.}, journal = {Nanoscale}, volume = {13}, number = {44}, pages = {18632-18646}, doi = {10.1039/d1nr06358h}, pmid = {34734624}, issn = {2040-3372}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Catalysis ; *Diabetes Mellitus, Experimental ; Mice ; Microbial Sensitivity Tests ; }, abstract = {We report a one-pot facile synthesis of highly photoresponsive bovine serum albumin (BSA) templated bismuth-copper sulfide nanocomposites (BSA-BiZ/CuxS NCs, where BiZ represents in situ formed Bi2S3 and bismuth oxysulfides (BOS)). As-formed surface vacancies and BiZ/CuxS heterojunctions impart superior catalytic, photodynamic and photothermal properties. Upon near-infrared (NIR) irradiation, the BSA-BiZ/CuxS NCs exhibit broad-spectrum antibacterial activity, not only against standard multidrug-resistant (MDR) bacterial strains but also against clinically isolated MDR bacteria and their associated biofilms. The minimum inhibitory concentration of BSA-BiZ/CuxS NCs is 14-fold lower than that of BSA-CuxS NCs because their multiple heterojunctions and vacancies facilitated an amplified phototherapeutic response. As-prepared BSA-BiZ/CuxS NCs exhibited substantial biofilm inhibition (90%) and eradication (>75%) efficiency under NIR irradiation. Furthermore, MRSA-infected diabetic mice were immensely treated with BSA-BiZ/CuxS NCs coupled with NIR irradiation by destroying the mature biofilm on the wound site, which accelerated the wound healing process via collagen synthesis and epithelialization. We demonstrate that BSA-BiZ/CuxS NCs with superior antimicrobial activity and high biocompatibility hold great potential as an effective photosensitive agent for the treatment of biofilm-associated infections.}, } @article {pmid34734186, year = {2021}, author = {Barnes, AMT and Frank, KL and Dale, JL and Manias, DA and Powers, JL and Dunny, GM}, title = {Enterococcus faecalis colonizes and forms persistent biofilm microcolonies on undamaged endothelial surfaces in a rabbit endovascular infection model.}, journal = {FEMS microbes}, volume = {2}, number = {}, pages = {xtab014}, pmid = {34734186}, issn = {2633-6685}, support = {R01 AI141961/AI/NIAID NIH HHS/United States ; T32 AI055433/AI/NIAID NIH HHS/United States ; }, abstract = {Infectious endocarditis (IE) is an uncommon disease with significant morbidity and mortality. The pathogenesis of IE has historically been described as a cascade of host-specific events beginning with endothelial damage and thrombus formation and followed by bacterial colonization of the nascent thrombus. Enterococcus faecalis is a Gram-positive commensal bacterial member of the gastrointestinal tract microbiota in most terrestrial animals and a leading cause of opportunistic biofilm-associated infections, including endocarditis. Here, we provide evidence that E. faecalis can colonize the endocardial surface without pre-existing damage and in the absence of thrombus formation in a rabbit endovascular infection model. Using previously described light and scanning electron microscopy techniques, we show that inoculation of a well-characterized E. faecalis lab strain in the marginal ear vein of New Zealand White rabbits resulted in rapid colonization of the endocardium throughout the heart within 4 days of administration. Unexpectedly, ultrastructural imaging revealed that the microcolonies were firmly attached directly to the endocardium in areas without morphological evidence of gross tissue damage. Further, the attached bacterial aggregates were not associated with significant cellular components of coagulation or host extracellular matrix damage repair (i.e. platelets). These results suggest that the canonical model of mechanical surface damage as a prerequisite for bacterial attachment to host sub-endothelial components is not required. Furthermore, these findings are consistent with a model of initial establishment of stable, endocarditis-associated E. faecalis biofilm microcolonies that may provide a reservoir for the eventual valvular infection characteristic of clinical endocarditis. The similarities between the E. faecalis colonization and biofilm morphologies seen in this rabbit endovascular infection model and our previously published murine gastrointestinal colonization model indicate that biofilm production and common host cell attachment factors are conserved in disparate mammalian hosts under both commensal and pathogenic contexts.}, } @article {pmid34733266, year = {2021}, author = {Zhang, M and Yu, Z and Lo, ECM}, title = {A New pH-Responsive Nano Micelle for Enhancing the Effect of a Hydrophobic Bactericidal Agent on Mature Streptococcus mutans Biofilm.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {761583}, pmid = {34733266}, issn = {1664-302X}, abstract = {The bactericidal effect on biofilm is the main challenge currently faced by antibacterial agents. Nanoscale drug-delivery materials can enhance biofilm penetrability and drug bioavailability, and have significant applications in the biomedical field. Dental caries is a typical biofilm-related disease, and the acidification of biofilm pH is closely related to the development of dental caries. In this study, a pH-responsive core-shell nano micelle (mPEG-b-PDPA) capable of loading hydrophobic antibacterial agents was synthesized and characterized, including its ability to deliver antibacterial agents within an acidic biofilm. The molecular structure of this diblock copolymer was determined by hydrogen-1 nuclear magnetic resonance ([1]H-NMR) and gel permeation chromatography (GPC). The characters of the micelles were studied by dynamic light scattering (DLS), TEM, pH titration, and drug release detection. It was found that the hydrophilic micelles could deliver bedaquiline, a hydrophobic antibacterial agent on S. mutans, in acidic environments and in mature biofilm. No cytotoxic effect on the periodontal cells was detected within 48 h. This pH-responsive micelle, being able to load hydrophobic antibacterial agent, has good clinical application potential in preventing dental caries.}, } @article {pmid34732760, year = {2021}, author = {Iannino, A and Fink, P and Weitere, M}, title = {Feedback between bottom-up and top-down control of stream biofilm mediated through eutrophication effects on grazer growth.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {21621}, pmid = {34732760}, issn = {2045-2322}, support = {FI 1548/7-1//Deutsche Forschungsgemeinschaft/ ; WE 3545/9-1//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Animals ; Biofilms/*growth & development ; Chlorella vulgaris/*growth & development ; *Ecosystem ; *Eutrophication ; Light ; Microalgae/*growth & development ; Nitrogen/metabolism ; Phosphorus/metabolism ; Rivers/*chemistry ; Snails/*physiology ; }, abstract = {Algal biofilms in streams are simultaneously controlled by light and nutrient availability (bottom-up control) and by grazing activity (top-down control). In addition to promoting algal growth, light and nutrients also determine the nutritional quality of algae for grazers. While short-term experiments have shown that grazers increase consumption rates of nutrient-poor algae due to compensatory feeding, nutrient limitation in the long run can constrain grazer growth and hence limit the strength of grazing activity. In this study, we tested the effects of light and phosphorus availability on grazer growth and thus on the long-term control of algal biomass. At the end of the experiment, algal biomass was significantly affected by light, phosphorus and grazing, but the interactive effects of the three factors significantly changed over time. At both high light and phosphorus supply, grazing did not initially reduce algal biomass, but the effect of grazing became stronger in the final three weeks of the experiment. Snail growth was enhanced by light, rather than phosphorus, suggesting that algal quantity rather than quality was the main limiting factor for grazer growth. Our results highlight the role of feedback effects and the importance of long-term experiments in the study of foodweb interactions.}, } @article {pmid34731576, year = {2021}, author = {Hagras, SAA and Hosny, AEMS and Helmy, OM and Salem-Bekhit, MM and Shakeel, F and Farrag, HA}, title = {Effect of sub-inhibitory concentrations of cefepime on biofilm formation by Pseudomonas aeruginosa.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {12}, pages = {894-901}, doi = {10.1139/cjm-2021-0229}, pmid = {34731576}, issn = {1480-3275}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cefepime ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; }, abstract = {This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½-[1]/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.}, } @article {pmid34729470, year = {2021}, author = {Park, S and Sauer, K}, title = {SagS and its unorthodox contributions to Pseudomonas aeruginosa biofilm development.}, journal = {Biofilm}, volume = {3}, number = {}, pages = {100059}, pmid = {34729470}, issn = {2590-2075}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; }, abstract = {The Pseudomonas aeruginosa orphan sensor SagS (PA2824) was initially reported as one of three orphan sensor kinases capable of activating HptB, a component of the HptB signaling pathway that intersects with the Gac/Rsm signaling pathway and fine-tunes P. aeruginosa motility and pathogenesis. Since then, this orphan sensor has been reported to be involved in other, unorthodox signaling pathways serving additional functions. The present review is aimed at summarizing the various functions of SagS, with an emphasis on its toggle or dual switch functions, and highlighting the role of SagS as a hub at which the various signaling pathways intersect, to regulate the transition from the planktonic to the sessile mode of growth, as well as the transition of surface-associated cells to a drug tolerant state.}, } @article {pmid34729469, year = {2021}, author = {Gannesen, AV and Schelkunov, MI and Geras'kina, OV and Makarova, NE and Sukhacheva, MV and Danilova, ND and Ovcharova, MA and Mart'yanov, SV and Pankratov, TA and Muzychenko, DS and Zhurina, MV and Feofanov, AV and Botchkova, EA and Plakunov, VK}, title = {Epinephrine affects gene expression levels and has a complex effect on biofilm formation in M icrococcus luteus strain C01 isolated from human skin.}, journal = {Biofilm}, volume = {3}, number = {}, pages = {100058}, pmid = {34729469}, issn = {2590-2075}, abstract = {In this study, the effect of epinephrine on the biofilm formation of Micrococcus luteus C01 isolated from human skin was investigated in depth for the first time. This hormone has a complex effect on biofilms in various systems. In a system with polytetrafluoroethylene (PTFE) cubes, treatment with epinephrine at a physiological concentration of 4.9 × 10[-9] M increased the total amount of 72-h biofilm biomass stained with crystal violet and increased the metabolic activity of biofilms, but at higher and lower concentrations, the treatment had no significant effect. On glass fiber filters, treatment with the hormone decreased the number of colony forming units (CFUs) and changed the aggregation but did not affect the metabolic activity of biofilm cells. In glass bottom plates examined by confocal microscopy, epinephrine notably inhibited the growth of biofilms. RNA-seq analysis and RT-PCR demonstrated reproducible upregulation of genes encoding Fe-S cluster assembly factors and cyanide detoxification sulfurtransferase, whereas genes encoding the co-chaperone GroES, the LysE superfamily of lysine exporters, short-chain alcohol dehydrogenase and the potential c-di-GMP phosphotransferase were downregulated. Our results suggest that epinephrine may stimulate matrix synthesis in M. luteus biofilms, thereby increasing the activity of NAD(H) oxidoreductases. Potential c-di-GMP pathway proteins are essential in these processes.}, } @article {pmid34727717, year = {2021}, author = {McMahon, S and Matthews, JJ and Brasier, A and Still, J}, title = {Late Ediacaran life on land: desiccated microbial mats and large biofilm streamers.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1962}, pages = {20211875}, pmid = {34727717}, issn = {1471-2954}, mesh = {Biofilms ; *Biological Evolution ; *Ecosystem ; Fossils ; Geologic Sediments/chemistry ; }, abstract = {The Ediacaran period witnessed transformational change across the Earth-life system, but life on land during this interval is poorly understood. Non-marine/transitional Ediacaran sediments preserve a variety of probable microbially induced sedimentary structures and fossil matgrounds, and the ecology, biogeochemistry and sedimentological impacts of the organisms responsible are now ripe for investigation. Here, we report well-preserved fossils from emergent siliciclastic depositional environments in the Ediacaran of Newfoundland, Canada. These include exquisite, mouldically preserved microbial mats with desiccation cracks and flip-overs, abundant Arumberia-type fossils and, most notably, assemblages of centimetre-to-metre-scale, subparallel, branching, overlapping, gently curving ribbon-like features preserved by aluminosilicate and phosphate minerals, with associated filamentous microfossils. We present morphological, petrographic and taphonomic evidence that the ribbons are best interpreted as fossilized current-induced biofilm streamers, the earliest record of an important mode of life (macroscopic streamer formation) for terrestrial microbial ecosystems today. Their presence shows that late Ediacaran terrestrial environments could produce substantial biomass, and supports recent interpretations of Arumberia as a current-influenced microbial mat fossil, which we here suggest existed on a 'streamer-arumberiamorph spectrum'. Finally, the absence of classic Ediacaran macrobiota from these rocks despite evidently favourable conditions for soft tissue preservation upholds the consensus that those organisms were exclusively marine.}, } @article {pmid34727414, year = {2022}, author = {Lin, Y and Zhou, X and Li, Y}, title = {Strategies for Streptococcus mutans biofilm dispersal through extracellular polymeric substances disruption.}, journal = {Molecular oral microbiology}, volume = {37}, number = {1}, pages = {1-8}, doi = {10.1111/omi.12355}, pmid = {34727414}, issn = {2041-1014}, mesh = {Biofilms ; *Dental Caries/microbiology/prevention & control ; *Dental Plaque/microbiology ; Extracellular Polymeric Substance Matrix/metabolism ; Humans ; Streptococcus mutans/genetics ; }, abstract = {Dental caries is one of the most prevalent and costly biofilm-dependent oral infectious diseases affecting most of the world's population. Streptococcus mutans, a major extracellular polymeric substance (EPS) producing bacteria in dental plaque, plays a vital role in human dental caries. EPS acts as the framework of dental plaque and promotes bacterial adhesion, cohesion, and environmental stress resistance and hinders the diffusion of nutrients and metabolic products. Since EPS is critical for biofilm lifestyle and virulence of cariogenic bacteria, EPS disruption could be a potential strategy to prevent caries. This review sought to summarize potential strategies to inhibit S. mutans biofilms through EPS disruption. The signal network intervention has a positive effect on S. mutans biofilm disruption, which could be achieved by using cyclic dimeric G/AMP inhibitors, quorum sensing inhibitors, and diffusible signal factors. Besides the enzyme degradation of exopolysaccharides, extracellular DNA, and proteins, other novel strategies, such as nanoparticles and phage therapy, could also promote EPS matrix disruption.}, } @article {pmid34727386, year = {2022}, author = {Paz, HES and Monteiro, MF and Stolf, CS and Altabtbaei, K and Casati, MZ and Casarin, RCV and Kumar, PS}, title = {Predicted functional and taxonomic analysis of subgingival biofilm of Grade C periodontitis in young patients under maintenance therapy.}, journal = {Journal of periodontology}, volume = {93}, number = {8}, pages = {1119-1130}, doi = {10.1002/JPER.21-0411}, pmid = {34727386}, issn = {1943-3670}, mesh = {Biofilms ; High-Throughput Nucleotide Sequencing ; Humans ; *Microbiota/genetics ; *Periodontitis/microbiology ; RNA, Ribosomal, 16S/genetics ; }, abstract = {BACKGROUND: In Grade C periodontitis in young patients (PerioC-Y), the functional roles of the subgingival community after years of periodontal treatment are still underexplored. This study evaluated the taxonomic and predicted functional content of the subgingival microbiome of PerioC-Y patients under supportive periodontal therapy (SPT).

METHODS: Clinical and microbiological data from subgingival biofilm were assessed from 10 PerioC-Y patients at two time points: at baseline and after 5.7 ± 1.3 years of SPT. This was compared with 15 patients without a history of periodontitis. The V1-V3 and V4-V5 regions of the 16S rRNA were sequenced using the Illumina Miseq. Microbial composition was evaluated by the core microbiome, and alpha- and beta-diversity. The microbiome functional content was predicted using Picrust2, and the gene differential abundance was analyzed with DESeq2.

RESULTS: Clinical improvements were seen in PerioC-Y-SPT. Differences in β-diversity between PerioC-Y and health were observed (health x PerioC-Y-baseline, P = 0.02; health x PerioC-Y-SPT, P = 0.05). Moreover, although β-diversity did not statistically change between baseline and SPT in PerioC-Y, the microbial correlation evidenced increased Streptococcus and decreased Treponema network contributions during SPT. Based on predicted functional data, treatment induced a reduction in genes related to flagellar protein and signal transduction in PerioC-Y. However, compared with healthy individuals, some genes remained more highly abundant in PerioC-Y-SPT, such as quorum sensing and efflux pump transporters.

CONCLUSION: Despite clinical improvements and a shift in taxonomic composition, the PerioC-Y patients' periodontal treatment was not enough to reach a similar microbiome to patients without disease experience. Some functional content in this biofilm remained altered in PerioC-Y regardless of disease control.}, } @article {pmid34727381, year = {2022}, author = {Morco, SR and Williams, DL and Jensen, BD and Bowden, AE}, title = {Structural biofilm resistance of carbon-infiltrated carbon nanotube coatings.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {40}, number = {8}, pages = {1953-1960}, doi = {10.1002/jor.25206}, pmid = {34727381}, issn = {1554-527X}, mesh = {Animals ; Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Nanotubes, Carbon ; *Odonata ; }, abstract = {Periprosthetic joint infection (PJI) is a devastating complication of orthopedic implant surgeries, such as total knee and hip arthroplasties. Treatment requires additional surgeries because antibiotics have limited efficacy due to biofilm formation and resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA). A non-pharmaceutical approach is needed, and examples of this are found in nature; dragonfly and cicada wings are antibacterial because of their nanopillar surface structure rather than their chemistry. Carbon-infiltrated carbon nanotube (CICNT) surfaces exhibit a similar nanopillar structure, and have been shown to facilitate osseointegration, and it is postulated that they might provide a structurally-derived resistance to bacterial proliferation and biofilm formation. The objective of this study was to test the biofilm resistance of CICNT coatings. Two types of CICNT were produced: a vertically aligned CNT forest on a silicon substrate using a layer of iron as the catalyst (CICNT-Si) and a random-oriented CNT forest on stainless steel (SS) substrate using the substrate as the catalyst (CICNT-SS). These were tested against SS and carbon controls. After 48 h in an MRSA biofilm reactor, samples demonstrated that both types of CICNT coatings significantly (p < 0.0001) reduced MRSA biofilm formation by 60%-80%. Morphologically, biofilm presence on both types of CICNT was also significantly reduced. Clinical Significance: Results suggest that a CICNT surface modification could be suitable and advantageous for medical devices susceptible to MRSA cell attachment and biofilm proliferation, particularly orthopedic implants.}, } @article {pmid34724823, year = {2021}, author = {Li, L and Li, Y and Zhu, F and Cheung, AL and Wang, G and Bai, G and Proctor, RA and Yeaman, MR and Bayer, AS and Xiong, YQ}, title = {New Mechanistic Insights into Purine Biosynthesis with Second Messenger c-di-AMP in Relation to Biofilm-Related Persistent Methicillin-Resistant Staphylococcus aureus Infections.}, journal = {mBio}, volume = {12}, number = {6}, pages = {e0208121}, pmid = {34724823}, issn = {2150-7511}, support = {R01 AI139244/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects ; Biosynthetic Pathways ; Cyclic AMP/*metabolism ; Daptomycin/pharmacology ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*metabolism ; Persistent Infection/*microbiology ; Purines/*biosynthesis ; Second Messenger Systems ; Staphylococcal Infections/*microbiology ; }, abstract = {Persistent methicillin-resistant Staphylococcus aureus (MRSA) endovascular infections represent a significant clinically challenging subset of invasive, life-threatening S. aureus infections. We have recently demonstrated that purine biosynthesis plays an important role in such persistent infections. Cyclic di-AMP (c-di-AMP) is an essential and ubiquitous second messenger that regulates many cellular pathways in bacteria. However, whether there is a regulatory connection between the purine biosynthesis pathway and c-di-AMP impacting persistent outcomes was not known. Here, we demonstrated that the purine biosynthesis mutant MRSA strain, the ΔpurF strain (compared to its isogenic parental strain), exhibited the following significant differences in vitro: (i) lower ADP, ATP, and c-di-AMP levels; (ii) less biofilm formation with decreased extracellular DNA (eDNA) levels and Triton X-100-induced autolysis paralleling enhanced expressions of the biofilm formation-related two-component regulatory system lytSR and its downstream gene lrgB; (iii) increased vancomycin (VAN)-binding and VAN-induced lysis; and (iv) decreased wall teichoic acid (WTA) levels and expression of the WTA biosynthesis-related gene, tarH. Substantiating these data, the dacA (encoding diadenylate cyclase enzyme required for c-di-AMP synthesis) mutant strain (dacAG206S strain versus its isogenic wild-type MRSA and dacA-complemented strains) showed significantly decreased c-di-AMP levels, similar in vitro effects as seen above for the purF mutant and hypersusceptible to VAN treatment in an experimental biofilm-related MRSA endovascular infection model. These results reveal an important intersection between purine biosynthesis and c-di-AMP that contributes to biofilm-associated persistence in MRSA endovascular infections. This signaling pathway represents a logical therapeutic target against persistent MRSA infections. IMPORTANCE Persistent endovascular infections caused by MRSA, including vascular graft infection syndromes and infective endocarditis, are significant and growing public health threats. A particularly worrisome trend is that most MRSA isolates from these patients are "susceptible" in vitro to conventional anti-MRSA antibiotics, such as VAN and daptomycin (DAP), based on Clinical and Laboratory Standards Institute breakpoints. Yet, these antibiotics frequently fail to eliminate these infections in vivo. Therefore, the persistent outcomes in MRSA infections represent a unique and important variant of classic "antibiotic resistance" that is only disclosed during in vivo antibiotic treatment. Given the high morbidity and mortality associated with the persistent infection, there is an urgent need to understand the specific mechanism(s) of this syndrome. In the current study, we demonstrate that a functional intersection between purine biosynthesis and the second messenger c-di-AMP plays an important role in VAN persistence in experimental MRSA endocarditis. Targeting this pathway may represent a potentially novel and effective strategy for treating these life-threatening infections.}, } @article {pmid34724237, year = {2022}, author = {Ejaz, S and Zubair, M and Rasool, N and Ahmed, F and Bilal, M and Ahmad, G and Altaf, AA and Shah, SAA and Rizwan, K}, title = {N-([1,1'-biaryl]-4-yl)-1-naphthamide-based scaffolds synthesis, their cheminformatics analyses, and screening as bacterial biofilm inhibitor.}, journal = {Journal of basic microbiology}, volume = {62}, number = {9}, pages = {1143-1155}, doi = {10.1002/jobm.202100288}, pmid = {34724237}, issn = {1521-4028}, support = {//Higher Education Commission, Pakistan/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; *Biofilms ; *Cheminformatics ; Escherichia coli ; Gram-Positive Bacteria ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; }, abstract = {Naphthamides have pharmacological potential as they express strong activities against microorganisms. The commercially available naphthoyl chloride and 4-bromoaniline were condensed in dry dichloromethane (DCM) in the presence of Et3 N to form N-(4-bromophenyl)-1-naphthamide (86%) (3). Using a Pd(0) catalyzed Suzuki-Miyaura Cross-Coupling reaction of (3) and various boronic acids, a series of N-([1,1'-biaryl]-4-yl)-1-naphthamide derivatives (4a-h) were synthesized in moderate to good yields. The synthesized derivatives were evaluated for cytotoxicity haemolytic assay and biofilm inhibition activity through in silico and in vitro studies. Molecular docking, ADME (absorption, distribution, metabolism, and excretion), toxicity risk, and other cheminformatics predict synthesized molecules as biologically active moieties, further validated through in vitro studies in which compounds (4c) and (4f) showed significant haemolytic activity whereas (4e) exhibited an efficient biofilm inhibition activity against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. When forming biofilms, bacteria become resistant to various antimicrobial treatments. Currently, research is focused on the development of agents that inhibit biofilm formation, thus the present work is valuable for preventing future drug resistance.}, } @article {pmid34723682, year = {2022}, author = {Li, Y and Wang, S and Li, S and Fei, J}, title = {Clindamycin-loaded titanium prevents implant-related infection through blocking biofilm formation.}, journal = {Journal of biomaterials applications}, volume = {36}, number = {7}, pages = {1231-1242}, doi = {10.1177/08853282211051183}, pmid = {34723682}, issn = {1530-8022}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology/therapeutic use ; Biofilms ; *Clindamycin/pharmacology/therapeutic use ; Coated Materials, Biocompatible/chemistry ; Rats ; Staphylococcus aureus ; *Titanium/chemistry ; }, abstract = {Implant-related infection is a disastrous complication. Surface modification of titanium is considered as an important strategy to prevent implant-related infection. However, there is no recognized surface modification strategy that can be applied in clinic so far. We explored a new strategy of coating. The clindamycin-loaded titanium was constructed by layer-by-layer self-assembly. The release of clindamycin from titanium was detected through high performance liquid chromatography. Different titanium was co-cultured with Staphylococcus aureus for 24 h in vitro, then the effect of different titanium on bacterial colonization and biofilm formation was determined by spread plate method and scanning electron microscopy. Cytotoxicity and cytocompatibility of clindamycin-loaded titanium on MC3T3-E1 cells were measured by CCK8. The antibacterial ability of clindamycin-loaded titanium in vivo was also evaluated using a rat model of osteomyelitis. The number of osteoclasts in bone defect was observed by tartrate-resistant acid phosphatase staining. Bacterial burden of surrounding tissues around the site of infection was calculated by tissue homogenate and colony count. Clindamycin-loaded titanium could release clindamycin slowly within 160 h. It reduced bacterial colonization by three orders of magnitude compare to control (p < .05) and inhibits biofilm formation in vitro. Cells proliferation and adhesion were similar on three titanium surfaces (p > .05). In vivo, clindamycin-loaded titanium improved bone healing, reduced microbial burden, and decreased the number of osteoclasts compared control titanium in the rat model of osteomyelitis. This study demonstrated that clindamycin-loaded titanium exhibited good biocompatibility, and showed antibacterial activity both in vivo and in vitro. It is promising and might have potential for clinical application.}, } @article {pmid34723645, year = {2022}, author = {Liu, Z and Hossain, SS and Morales Moreira, Z and Haney, CH}, title = {Putrescine and Its Metabolic Precursor Arginine Promote Biofilm and c-di-GMP Synthesis in Pseudomonas aeruginosa.}, journal = {Journal of bacteriology}, volume = {204}, number = {1}, pages = {e0029721}, pmid = {34723645}, issn = {1098-5530}, support = {PJT - 169051//CIHR/Canada ; }, mesh = {Arginine/*pharmacology ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/biosynthesis ; Gene Expression Regulation, Bacterial/*drug effects/physiology ; Pseudomonas aeruginosa/drug effects/*physiology ; Putrescine/*pharmacology ; Up-Regulation ; }, abstract = {Pseudomonas aeruginosa, an opportunistic bacterial pathogen, can synthesize and catabolize several small cationic molecules known as polyamines. In several clades of bacteria, polyamines regulate biofilm formation, a lifestyle-switching process that confers resistance to environmental stress. The polyamine putrescine and its biosynthetic precursors, l-arginine and agmatine, promote biofilm formation in Pseudomonas spp. However, it remains unclear whether the effect is a direct effect of polyamines or occurs through a metabolic derivative. Here, we used a genetic approach to demonstrate that putrescine accumulation, either through disruption of the spermidine biosynthesis pathway or the catabolic putrescine aminotransferase pathway, promoted biofilm formation in P. aeruginosa. Consistent with this observation, exogenous putrescine robustly induced biofilm formation in P. aeruginosa that was dependent on putrescine uptake and biosynthesis pathways. Additionally, we show that l-arginine, the biosynthetic precursor of putrescine, also promoted biofilm formation but did so by a mechanism independent of putrescine or agmatine conversion. We found that both putrescine and l-arginine induced a significant increase in the intracellular level of bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) (c-di-GMP), a bacterial second messenger widely found in Proteobacteria that upregulates biofilm formation. Collectively these data show that putrescine and its metabolic precursor, arginine, promote biofilm and c-di-GMP synthesis in P. aeruginosa. IMPORTANCE Biofilm formation allows bacteria to physically attach to a surface, confer tolerance to antimicrobial agents, and promote resistance to host immune responses. As a result, the regulation of biofilm formation is often crucial for bacterial pathogens to establish chronic infections. A primary mechanism of biofilm promotion in bacteria is the molecule c-di-GMP, which promotes biofilm formation. The level of c-di-GMP is tightly regulated by bacterial enzymes. In this study, we found that putrescine, a small molecule ubiquitously found in eukaryotic cells, robustly enhances P. aeruginosa biofilm and c-di-GMP. We propose that P. aeruginosa may sense putrescine as a host-associated signal that triggers a lifestyle switch that favors chronic infection.}, } @article {pmid34722367, year = {2021}, author = {Jayaweera, JAAS and Kothalawala, M}, title = {Use of high-dose ciprofloxacin for recurrent biofilm-forming multidrug-resistant Klebsiella pneumoniae bacteremia.}, journal = {Germs}, volume = {11}, number = {3}, pages = {449-453}, pmid = {34722367}, issn = {2248-2997}, abstract = {INTRODUCTION: Klebsiella pneumoniae is a significant nosocomial pathogen. We aimed to assess the clinical success following high-dose ciprofloxacin for recurrent bacteremia from biofilm-forming multidrug resistant Klebsiella pneumoniae in a liver transplanted patient.

CASE REPORT: A 55-year-old male had undergone liver transplantation and at day 10 he developed fever and dysuria. Two blood cultures became positive and were identified by Vitek2 (BioMérieux, USA) as K. pneumoniae. From his urine K. pneumoniae was isolated. Based on antimicrobial susceptibility (AST) panel (Vitek2), i.v. meropenem 1 g 8 hourly and i.v. amikacin 15 mg/kg/ daily (5 days) were started (the isolate was ciprofloxacin-resistant). Following 14 days of meropenem he was discharged and 3 days later he was readmitted with fever and dysuria. Since the blood and urine isolate was K. pneumoniae, based on AST 21 days of meropenem were given, the patient was discharged and 3 days later he was readmitted with fever and dysuria. Since this was the 3[rd] episode with K. pneumoniae bacteremia, to exclude the focus of infection contrast-enhanced computed tomography and [18]F-fluorodeoxyglucose-positron emission tomography were done but both were normal.Based on multilocus sequence typing (MLST) and microtiter plate assay, biofilm forming magA(K1)-positive (+) K. pneumoniae CC23 was found. The patient was having continuous asymptomatic bacteriuria with similar (magA(K1)-positive (+) K. pneumoniae CC23) isolate; we opted for high dose oral ciprofloxacin (800 mg, 8 hourly) for 7 days.

CONCLUSIONS: Following a high dose of oral ciprofloxacin, we were able to achieve urinary microbial clearance and a permanent cure following (magA(K1)-positive (+) K. pneumoniae CC23) bacteremia. This could be a promising therapy to achieve microbial clearance from biofilm-forming multidrug-resistant K. pneumoniae.}, } @article {pmid34722331, year = {2021}, author = {Rodríguez Sánchez, F and Verspecht, T and Castro, AB and Pauwels, M and Andrés, CR and Quirynen, M and Teughels, W}, title = {Antimicrobial Mechanisms of Leucocyte- and Platelet Rich Fibrin Exudate Against Planktonic Porphyromonas gingivalis and Within Multi-Species Biofilm: A Pilot Study.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {722499}, pmid = {34722331}, issn = {2235-2988}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; Exudates and Transudates ; Pilot Projects ; Plankton ; *Platelet-Rich Fibrin ; Porphyromonas gingivalis ; }, abstract = {Leucocyte- and platelet rich fibrin (L-PRF) is an autologous biomaterial used in regenerative procedures. It has an antimicrobial activity against P. gingivalis although the mechanism is not fully understood. It was hypothesized that L-PRF exudate releases hydrogen peroxide and antimicrobial peptides that inhibit P. gingivalis growth. Agar plate and planktonic culture experiments showed that the antimicrobial effect of L-PRF exudate against P. gingivalis was supressed by peroxidase or pepsin exposure. In developing multi-species biofilms, the antimicrobial effect of L-PRF exudate was blocked only by peroxidase, increasing P. gingivalis growth with 1.3 log genome equivalents. However, no effect was shown on other bacteria. Pre-formed multi-species biofilm trials showed no antimicrobial effect of L-PRF exudate against P. gingivalis or other species. Our findings showed that L-PRF exudate may release peroxide and peptides, which may be responsible for its antimicrobial effect against P. gingivalis. In addition, L-PRF exudate had an antimicrobial effect against P. gingivalis in an in vitro developing multi-species biofilm.}, } @article {pmid34721354, year = {2021}, author = {Boudet, A and Sorlin, P and Pouget, C and Chiron, R and Lavigne, JP and Dunyach-Remy, C and Marchandin, H}, title = {Biofilm Formation in Methicillin-Resistant Staphylococcus aureus Isolated in Cystic Fibrosis Patients Is Strain-Dependent and Differentially Influenced by Antibiotics.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {750489}, pmid = {34721354}, issn = {1664-302X}, abstract = {Cystic fibrosis (CF) is a genetic disease with lung abnormalities making patients particularly predisposed to pulmonary infections. Staphylococcus aureus is the most frequently identified pathogen, and multidrug-resistant strains (MRSA, methicillin-resistant S. aureus) have been associated with more severe lung dysfunction leading to eradication recommendations. Diverse bacterial traits and adaptive skills, including biofilm formation, may, however, make antimicrobial therapy challenging. In this context, we compared the ability of a collection of genotyped MRSA isolates from CF patients to form biofilm with and without antibiotics (ceftaroline, ceftobiprole, linezolid, trimethoprim, and rifampicin). Our study used standardized approaches not previously applied to CF MRSA, the BioFilm Ring test® (BRT®), the Antibiofilmogram®, and the BioFlux™ 200 system which were adapted for use with the artificial sputum medium (ASM) mimicking conditions more relevant to the CF lung. We included 63 strains of 10 multilocus sequence types (STs) isolated from 35 CF patients, 16 of whom had chronic colonization. The BRT® showed that 27% of the strains isolated in 37% of the patients were strong biofilm producers. The Antibiofilmogram® performed on these strains showed that broad-spectrum cephalosporins had the lowest minimum biofilm inhibitory concentrations (bMIC) on a majority of strains. A focus on four chronically colonized patients with inclusion of successively isolated strains showed that ceftaroline, ceftobiprole, and/or linezolid bMICs may remain below the resistance thresholds over time. Studying the dynamics of biofilm formation by strains isolated 3years apart in one of these patients using BioFlux™ 200 showed that inhibition of biofilm formation was observed for up to 36h of exposure to bMIC and ceftaroline and ceftobiprole had a significantly greater effect than linezolid. This study has brought new insights into the behavior of CF MRSA which has been little studied for its ability to form biofilm. Biofilm formation is a common characteristic of prevalent MRSA clones in CF. Early biofilm formation was strain-dependent, even within a sample, and not only observed during chronic colonization. Ceftaroline and ceftobiprole showed a remarkable activity with a long-lasting inhibitory effect on biofilm formation and a conserved activity on certain strains adapted to the CF lung environment after years of colonization.}, } @article {pmid34719734, year = {2021}, author = {Zhao, L and Liu, Q and Huang, Q and Liu, F and Liu, H and Wang, G}, title = {Isocitrate dehydrogenase of Bacillus cereus is involved in biofilm formation.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {12}, pages = {207}, pmid = {34719734}, issn = {1573-0972}, support = {212300410331//Science & Technology Research and Development Project of Henan Province/ ; }, mesh = {Bacillus cereus/*enzymology/genetics/*metabolism ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Citric Acid/metabolism ; Citric Acid Cycle ; Gene Expression Regulation, Bacterial ; Hydrogen-Ion Concentration ; Isocitrate Dehydrogenase/*metabolism ; Isocitrates ; Protein Serine-Threonine Kinases/genetics ; Staphylococcus aureus/metabolism ; }, abstract = {Isocitrate dehydrogenase (IDH), a key enzyme in the TCA cycle, participates in the formation of biofilms in Staphylococcus aureus, but it remains to be clarified whether it is involved in the formation of Bacillus cereus biofilms. In this study, we scanned the genome of B. cereus 0-9 and found a gene encoding isocitrate dehydrogenase (FRY47_22620) named icdH. The IcdH protein was expressed and purified. The enzyme activity assay showed that the protein had IDH activity dependent on NADP[+], indicating that this gene encoded an IDH. The ΔicdH mutant and its complemented strains were obtained by a homologous recombination strategy, and crystal violet data and CLSM were measured. The results showed that the biofilm yield of the mutant ΔicdH decreased, and the biofilm morphology also changed, while the growth of ΔicdH was not affected. The extracellular pH and citric acid content results showed that the ΔicdH mutant exhibited citric acid accumulation and acidification of the extracellular matrix. In addition, the addition of excess Fe[3+] restored the biofilm formation of the ΔicdH mutant. It is speculated that IDH in B. cereus may regulate biofilm formation by modulating intracellular redox homeostasis. In addition, we found that the icdH deletion of B. cereus 0-9 could result in a reduced sporulation rate, which was significantly different from sporulation in B. subtilis caused by interruption of the stage I sporulation process due to icdH loss. All the above results provide us with new insights for further research on IDH.}, } @article {pmid34718136, year = {2021}, author = {Xu, A and Zhang, X and Wang, T and Xin, F and Ma, LZ and Zhou, J and Dong, W and Jiang, M}, title = {Rugose small colony variant and its hyper-biofilm in Pseudomonas aeruginosa: Adaption, evolution, and biotechnological potential.}, journal = {Biotechnology advances}, volume = {53}, number = {}, pages = {107862}, doi = {10.1016/j.biotechadv.2021.107862}, pmid = {34718136}, issn = {1873-1899}, mesh = {Biofilms ; Ecosystem ; Humans ; Persistent Infection ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; }, abstract = {One of the hallmarks of the environmental bacterium Pseudomonas aeruginosa is its excellent ecological flexibility, which can thrive in diverse ecological niches. In different ecosystems, P. aeruginosa may use different strategies to survive, such as forming biofilms in crude oil environment, converting to mucoid phenotype in the cystic fibrosis (CF) lung, or becoming persisters when treated with antibiotics. Rugose small colony variants (RSCVs) are the adaptive mutants of P. aeruginosa, which can be frequently isolated from chronic infections. During the past years, there has been a renewed interest in using P. aeruginosa as a model organism to investigate the RSCVs formation, persistence and pathogenesis, as RSCVs represent a hyper-biofilm formation, high adaptability, high-tolerance sub-population in biofilms. This review will briefly summarize recent advances regarding the phenotypic, genetic and host interaction associated with RSCVs, with an emphasis on P. aeruginosa. Meanwhile, some non-pathogenic bacteria such as Pseudomonas fluorescence, Pseudomonas putida and Bacillus subtilis will be also included. Remarkable emphasis is given on intrinsic functions of such hyper-biofilm formation characteristic as well as its potential applications in several biocatalytic transformations including wastewater treatment, microbial fermentation, and plastic degradation. Hopefully, this review will attract the interest of researchers in various fields and shape future research focused not only on evolutionary biology but also on biotechnological applications related to RSCVs.}, } @article {pmid34717138, year = {2022}, author = {Perez-Palacios, P and Gual-de-Torrella, A and Delgado-Valverde, M and Oteo-Iglesias, J and Hidalgo-Díaz, C and Pascual, Á and Fernández-Cuenca, F}, title = {Transfer of plasmids harbouring blaOXA-48-like carbapenemase genes in biofilm-growing Klebsiella pneumoniae: Effect of biocide exposure.}, journal = {Microbiological research}, volume = {254}, number = {}, pages = {126894}, doi = {10.1016/j.micres.2021.126894}, pmid = {34717138}, issn = {1618-0623}, mesh = {*Bacterial Proteins/genetics ; Biofilms ; *Disinfectants/pharmacology ; Escherichia coli/drug effects/genetics ; *Klebsiella pneumoniae/drug effects/enzymology/genetics ; *Plasmids/genetics ; *beta-Lactamases/genetics ; }, abstract = {The spread of OXA-48-encoding plasmids from Klebsiella pneumoniae (OXA-48-Kpn), especially successful high-risk (HR) clones, is a growing concern. Biofilm formation can contribute to the dissemination of OXA-48-Kpn. It is not known whether biocides can affect the transfer of OXA-48-Kpn in biofilm. The aim of this study was to evaluate the effect of biocides on the conjugation frequency (CF) of OXA-48-Kpn in both biofilm and planktonic cultures. For that, seven OXA-48-Kpn isolates (4 belonging to HR clones and 3 to non-HR clones) were selected as donors. Each isolate was mixed (1:1) with Escherichia coli J53 (recipient) and grown on polystyrene microplates without biocides (control) and with 0.25x MIC of triclosan (TRI), chlorhexidine digluconate (CHX), povidone-iodine (POV), sodium hypochlorite (SOD) or ethanol (ETH). The CF was calculated as the number of transconjugants/number of E. coli J53. The results showed that for isolates growing in the absence of biocide, the mean fold change in the CF in biofilm with respect to that determined in planktonic cells (CF-BF/CF-PK) was 0.2 in non-HR isolates and ranged from 2.0 to 14.7 in HR isolates. In HR isolates grown in the presence of biocide, especially CHX, TRI, and ETH, the fold changes in CF-BF/CF-PK decreased, whereas in non-HR isolates the fold changes were similar or increased slightly with CHX, ETH, SOD and POV. In conclusion, the fold changes in the CF-BF/CF-PK are higher in HR isolates comparing to non-HR isolates in abscence of biocides. The fold changes in CF-BF/CF-PK of the HR isolates in the presence of biocides varied with the type of biocides, whereas in non-HR isolates, biocides have no significant effect, or produce only a slight increase in the fold change of CF-BF/CF-PK.}, } @article {pmid34717106, year = {2022}, author = {Xiong, Z and Zheng, J and Sun, H and Hu, J and Sheng, X and He, L}, title = {Biofilm-overproducing Bacillus amyloliquefaciens P29ΔsinR decreases Pb availability and uptake in lettuce in Pb-polluted soil.}, journal = {Journal of environmental management}, volume = {302}, number = {Pt A}, pages = {114016}, doi = {10.1016/j.jenvman.2021.114016}, pmid = {34717106}, issn = {1095-8630}, mesh = {*Bacillus amyloliquefaciens/genetics ; Biofilms ; Cadmium/analysis ; Lead ; Lettuce ; Plant Roots/chemistry ; Soil ; *Soil Pollutants/analysis ; }, abstract = {In this study, one mutant strain P29ΔsinR with increased biofilm production was constructed from a biofilm-producing Bacillus amyloliquefaciens strain P29. Then, the effect of strain P29 and its biofilm-overproducing mutant strain P29ΔsinR on Pb availability and accumulation in lettuce and the associated mechanisms were characterized in the Pb-contaminated soil. The live strains P29 and P29ΔsinR increased the dry masses of roots and edible tissues by 31-74% compared to the controls. The live strains P29 and P29ΔsinR reduced the Pb uptake in the roots by 36-52% and edible tissues by 24-43%, Pb bioconcentration factor by 36-52%, and rhizosphere soil available Pb content by 12-25%, respectively, compared to the controls. The live strains P29 and P29ΔsinR increased the pH, proportion of biofilm-producing bacteria by 46-154%, contents of polysaccharides by 99-139% and proteins by 32-57%, and gene relative abundances of epsC by 7.1-10.2-fold, tasA by 10.3-10.8-fold, and sipW by 6.5-26.1-fold, which were associated with biofilm formation and Pb adsorption in the rhizosphere soils, respectively, compared to the controls. Furthermore, the mutant strain P29ΔsinR showed higher ability to reduce Pb availability and uptake in lettuce and increase the pH, proportion of biofilm-producing bacteria, polysaccharide and protein contents, and relative abundances of these genes. These results showed that the biofilm-overproducing strain P29ΔsinR induced lower Pb availability and accumulation in the vegetable and more biofilm-producing bacteria, polysaccharide and protein production, and Pb-immobilizing related gene abundances in the Pb-contaminated soil.}, } @article {pmid34716343, year = {2021}, author = {Zarnowski, R and Noll, A and Chevrette, MG and Sanchez, H and Jones, R and Anhalt, H and Fossen, J and Jaromin, A and Currie, C and Nett, JE and Mitchell, A and Andes, DR}, title = {Coordination of fungal biofilm development by extracellular vesicle cargo.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {6235}, pmid = {34716343}, issn = {2041-1723}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Candida albicans/cytology/drug effects/pathogenicity/*physiology ; Candidiasis/microbiology ; Cell Adhesion/drug effects ; Central Venous Catheters/microbiology ; Drug Resistance, Fungal/drug effects/*physiology ; Endosomal Sorting Complexes Required for Transport/metabolism ; Extracellular Matrix/chemistry ; Extracellular Vesicles/chemistry/*metabolism ; Female ; Fungal Proteins/genetics/*metabolism ; Mutation ; Rats ; }, abstract = {The fungal pathogen Candida albicans can form biofilms that protect it from drugs and the immune system. The biofilm cells release extracellular vesicles (EVs) that promote extracellular matrix formation and resistance to antifungal drugs. Here, we define functions for numerous EV cargo proteins in biofilm matrix assembly and drug resistance, as well as in fungal cell adhesion and dissemination. We use a machine-learning analysis of cargo proteomic data from mutants with EV production defects to identify 63 candidate gene products for which we construct mutant and complemented strains for study. Among these, 17 mutants display reduced biofilm matrix accumulation and antifungal drug resistance. An additional subset of 8 cargo mutants exhibit defects in adhesion and/or dispersion. Representative cargo proteins are shown to function as EV cargo through the ability of exogenous wild-type EVs to complement mutant phenotypic defects. Most functionally assigned cargo proteins have roles in two or more of the biofilm phases. Our results support that EVs provide community coordination throughout biofilm development in C. albicans.}, } @article {pmid34715367, year = {2022}, author = {Wang, Z and Peng, Y and Zhou, Y and Zhang, S and Tan, J and Li, H and He, D and Deng, L}, title = {Pd-Cu nanoalloy for dual stimuli-responsive chemo-photothermal therapy against pathogenic biofilm bacteria.}, journal = {Acta biomaterialia}, volume = {137}, number = {}, pages = {276-289}, doi = {10.1016/j.actbio.2021.10.028}, pmid = {34715367}, issn = {1878-7568}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Drug Liberation ; Phototherapy ; *Photothermal Therapy ; Staphylococcus aureus ; }, abstract = {Photothermal therapy (PTT) is a promising strategy for antimicrobial therapy. However, the application of PTT to treat bacterial infections remains a challenge as the high temperature required for bacterial elimination can partly damage healthy tissues. Selecting the appropriate treatment temperature is therefore a key factor for PTT. In this work, we designed a near-infrared/pH dual stimuli-responsive activated procedural antibacterial system based on zeolitic imidazolate framework-8 (ZIF-8), which was bottom-up synthesized and utilized to encapsulate both Pd-Cu nanoalloy (PC) and the antibiotic amoxicillin (AMO). This procedural antibacterial therapy comprises chemotherapy (CT) and PTT. The former disrupts the bacterial cell wall by releasing AMO in an acidic environment, which depends on the sensitive response of ZIF-8 to pH value change. With the progression in time, the AMO release rate decreased gradually. The latter can then significantly stimulate drug release and further complete the antibacterial effect. This impactful attack consisted of two waves that constitute the procedural therapy for bacterial infection. Accordingly, the treatment temperature required for antibacterial therapy can be significantly lowered under this mode of treatment. This antibacterial system has a significant therapeutic effect on planktonic bacteria (G[+]/G[-]) and their biofilms and also has good biocompatibility; thus, it provides a promising strategy to develop an effective and safe treatment against bacterial infections. STATEMENT OF SIGNIFICANCE: We have developed a near infrared/pH dual stimuli-responsive activated procedural antibacterial system that combines enhanced antibiotic delivery with photothermal therapy and has highly efficient antimicrobial activity. The antibacterial effect of this therapy was based on two mechanisms of action: chemotherapy, in which the bacterial cell wall was first destroyed, followed by photothermal therapy. After exposure to irradiation with an 808 nm laser, the inhibition rates were 99.8% and 99.1% for Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and the clearance rates for their established biofilms were 75.3% and 74.8%, respectively. Thus, this procedural antibacterial therapy has shown great potentiality for use in the photothermal therapy of bacterial infectious diseases, including biofilm elimination.}, } @article {pmid34715100, year = {2022}, author = {Pan, QR and Jiang, PY and Lai, BL and Qian, YB and Huang, LJ and Liu, XX and Li, N and Liu, ZQ}, title = {Co, N co-doped hierarchical porous carbon as efficient cathode electrocatalyst and its impact on microbial community of anode biofilm in microbial fuel cell.}, journal = {Chemosphere}, volume = {291}, number = {Pt 1}, pages = {132701}, doi = {10.1016/j.chemosphere.2021.132701}, pmid = {34715100}, issn = {1879-1298}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Carbon ; Electrodes ; *Microbiota ; Porosity ; Silicon Dioxide ; }, abstract = {The exploration of low-cost, long-term stable, and highly electrochemically active cathode catalysts is important for the practical application of microbial fuel cell (MFC). In this work, a series of the 3D hierarchical porous Co-N-C (3DHP Co-N-C) materials are designed and synthesized by a metal-organic framework ZIF-67 as a precursor and SiO2 sphere of different sizes as the hard template. The 3DHP Co-N-C-2 with 129 nm macropore exhibits excellent ORR performance in 0.1 M KOH solution with a half-wave potential of 0.80 V vs. RHE and superior durability than Pt/C (20%) due to the specific macropore-mesopore-micropore structure that exposes a large number of active sites and accelerates the electrolyte transport and oxygen diffusion. The MFC with 3DHP Co-N-C-2 as the cathode catalysts shows excellent performance with a maximum power density of 426.9±7.87 mW m[-2] and favorable durability after 50 d of operation. In addition, 16s rDNA results reveal the presence of different dominant electrogenic bacteria and different abundance of important non-electrogenic bacteria in the anode biofilm in MFCs using cathode catalysts with different ORR activity. And 3DHP Co-N-C-2 was found to be beneficial to the synergistic effect of electrogenic and non-electrogenic bacteria. This study explores electrocatalysts in terms of both electrocatalytic activity and anode microorganisms, providing new and comprehensive insights into the power generation of MFC.}, } @article {pmid34714647, year = {2021}, author = {Zhang, J and Zhang, M and Wang, Y and Donarski, E and Gahlmann, A}, title = {Optically Accessible Microfluidic Flow Channels for Noninvasive High-Resolution Biofilm Imaging Using Lattice Light Sheet Microscopy.}, journal = {The journal of physical chemistry. B}, volume = {125}, number = {44}, pages = {12187-12196}, pmid = {34714647}, issn = {1520-5207}, support = {R01 GM139002/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacteria ; Biofilms ; *Microfluidics ; *Microscopy ; Refractometry ; }, abstract = {Imaging platforms that enable long-term, high-resolution imaging of biofilms are required to study cellular level dynamics within bacterial biofilms. By combining high spatial and temporal resolution and low phototoxicity, lattice light sheet microscopy (LLSM) has made critical contributions to the study of cellular dynamics. However, the power of LLSM has not yet been leveraged for biofilm research because the open-on-top imaging geometry using water-immersion objective lenses is not compatible with living bacterial specimens; bacterial growth on the microscope's objective lenses makes long-term time-lapse imaging impossible and raises considerable safety concerns for microscope users. To make LLSM compatible with pathogenic bacterial specimens, we developed hermetically sealed, but optically accessible, microfluidic flow channels that can sustain bacterial biofilm growth for multiple days under precisely controllable physical and chemical conditions. To generate a liquid- and gas-tight seal, we glued a thin polymer film across a 3D-printed channel, where the top wall had been omitted. We achieved negligible optical aberrations by using polymer films that precisely match the refractive index of water. Bacteria do not adhere to the polymer film itself, so that the polymer window provides unobstructed optical access to the channel interior. Inside the flow channels, biofilms can be grown on arbitrary, even nontransparent, surfaces. By integrating this flow channel with LLSM, we were able to record the growth of S. oneidensis MR-1 biofilms over several days at cellular resolution without any observable phototoxicity or photodamage.}, } @article {pmid34710612, year = {2022}, author = {Xu, B and Ng, TCA and Huang, S and He, M and Varjani, S and Ng, HY}, title = {Quorum quenching affects biofilm development in an anaerobic membrane bioreactor (AnMBR): from macro to micro perspective.}, journal = {Bioresource technology}, volume = {344}, number = {Pt B}, pages = {126183}, doi = {10.1016/j.biortech.2021.126183}, pmid = {34710612}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; *Extracellular Polymeric Substance Matrix ; *Quorum Sensing ; }, abstract = {The first experimental study on the influence of acyl homoserine lactones (AHLs) degrading quorum quenching (QQ) consortium on the dynamics of biofilm bio-communities (i.e., from suspended biomass to initial biofilm and mature biofilm) in an anaerobic membrane bioreactor (AnMBR) at a microscopic scale (denoted as QQAnMBR) was reported. QQ did not change the overall bacterial community of the suspended biomass, inclusive of the key functional bacteria. Moreover, the retarded initial biofilm formation was attributed to not only the lower extracellular polymeric substance content of suspended biomass, but also the decelerated colonization of the AHL-regulated low-abundance in suspended biomass but pioneering keystone taxa Rhodocyclaceae;g- on membrane surface. However, pioneering fouling-related taxa such as Sulfurovum and Rhodocyclaceae;g- still played paramount roles in the delayed initial biofilm formation in the QQAnMBR. Furthermore, the microbial assemblies of the mature biofilm were changed in the QQAnMBR, probably attributable to the abiotic microbial floc attachment.}, } @article {pmid34710604, year = {2022}, author = {Lin, Z and Zhou, J and He, L and He, X and Pan, Z and Wang, Y and He, Q}, title = {High-temperature biofilm system based on heterotrophic nitrification and aerobic denitrification treating high-strength ammonia wastewater: Nitrogen removal performances and temperature-regulated metabolic pathways.}, journal = {Bioresource technology}, volume = {344}, number = {Pt A}, pages = {126184}, doi = {10.1016/j.biortech.2021.126184}, pmid = {34710604}, issn = {1873-2976}, mesh = {Aerobiosis ; Ammonia ; Biofilms ; Denitrification ; Heterotrophic Processes ; Metabolic Networks and Pathways ; *Nitrification ; Nitrogen ; Temperature ; *Wastewater ; }, abstract = {Conventional autotrophic nitrification process is difficult to treat high-temperature wastewater with high-strength ammonia. In this study, a high-temperature (50 °C) biofilm system based on heterotrophic nitrification and aerobic denitrification (HNAD) was established. The results showed that the HNAD process was high temperature resistant, and the nitrogen removal performance, pathway and microbial mechanism varied remarkably at different temperatures. The high-temperature system showed excellent nitrogen and COD removal capacities at 50 °C. Ammonia oxidation was mainly undertaken by heterotrophic nitrification, while anoxic and aerobic pathways worked in concert for denitrification. High-throughput sequencing indicated that heterotrophic nitrifying bacteria (8.58%) and denitrifying bacteria (52.88%) were dominant at 50 °C. Metagenomic analysis further suggested that the carbon metabolism was up-regulated in response to the increasing temperature, so more energy was generated, thereby promoting the HNAD-related nitrogen removal pathways. The study revealed the microbial mechanism of HNAD at high temperature and provided new insights into high-temperature biological nitrogen removal.}, } @article {pmid34710593, year = {2022}, author = {Liu, X and Tang, P and Liu, Y and Xie, W and Chen, C and Li, T and He, Q and Bao, J and Tiraferri, A and Liu, B}, title = {Efficient removal of organic compounds from shale gas wastewater by coupled ozonation and moving-bed-biofilm submerged membrane bioreactor.}, journal = {Bioresource technology}, volume = {344}, number = {Pt A}, pages = {126191}, doi = {10.1016/j.biortech.2021.126191}, pmid = {34710593}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Dissolved Organic Matter ; Membranes, Artificial ; Natural Gas ; *Ozone ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Shale gas wastewater (SGW) with complex composition and high salinity needs an economical and efficient method of treatment with the main goal to remove organics. In this study, a coupled system consisting of ozonation and moving-bed-biofilm submerged membrane bioreactor (MBBF-SMBR) was comprehensively evaluated for SGW treatment and compared with a similar train comprising ozonation and submerged membrane bioreactor (SMBR) without addition of carriers attaching biofilm. The average removal rates of MBBF-SMBR were 77.8% for dissolved organic carbon (DOC) and 37.0% for total nitrogen (TN), higher than those observed in SMBR, namely, 73.9% for DOC and 18.6% for TN. The final total membrane resistance in SMBR was 40.1% higher than that in MBBF-SMBR. Some genera that specifically contribute to organic removal were identified. Enhanced gene allocation for membrane transport and nitrogen metabolism was found in MBBF-SMBR biofilm, implying that this system has significant industrial application potential for organics removal from SGW.}, } @article {pmid34709974, year = {2022}, author = {Xu, Z and Huang, T and Min, D and Soteyome, T and Lan, H and Hong, W and Peng, F and Fu, X and Peng, G and Liu, J and Kjellerup, BV}, title = {Regulatory network controls microbial biofilm development, with Candida albicans as a representative: from adhesion to dispersal.}, journal = {Bioengineered}, volume = {13}, number = {1}, pages = {253-267}, pmid = {34709974}, issn = {2165-5987}, mesh = {Antifungal Agents/*therapeutic use ; *Biofilms/drug effects/growth & development ; Candida albicans/*physiology ; *Candidiasis/drug therapy/metabolism/mortality ; Fungal Proteins/metabolism ; Humans ; }, abstract = {Microorganisms mainly exist in the form of biofilm in nature. Biofilm can contaminate food and drinking water system, as well as cause chronic wound infections, thereby posing a potential threat to public health safety. In the last two decades, researchers have made efforts to investigate the genetic contributors control different stages of biofilm development (adherence, initiation, maturation, and dispersal). As an opportunistic pathogen, C. albicans causes severe superficial or systemic infections with high morbidity and mortality under conditions of immune dysfunction. It has been reported that 80% of C. albicans infections are directly or indirectly associated with biofilm formation on host or abiotic surfaces including indwelling medical devices, resulting in high morbidity and mortality. Significantly, the outcome of C. albicans biofilm development includes enhanced invasion, exacerbated inflammatory responses and intrinsic resistance to antimicrobial chemotherapy. Thus, this review aimed at providing a comprehensive overview of the regulatory network controls microbial biofilm development, with C. albicans as a representative, served as reference for therapeutic targets.}, } @article {pmid34708004, year = {2021}, author = {Islam, MM and Kim, K and Lee, JC and Shin, M}, title = {LeuO, a LysR-Type Transcriptional Regulator, Is Involved in Biofilm Formation and Virulence of Acinetobacter baumannii.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {738706}, pmid = {34708004}, issn = {2235-2988}, mesh = {*Acinetobacter baumannii/genetics ; Animals ; Biofilms ; Virulence/genetics ; }, abstract = {Acinetobacter baumannii is an important nosocomial pathogen that can survive in different environmental conditions and poses a severe threat to public health due to its multidrug resistance properties. Research on transcriptional regulators, which play an essential role in adjusting to new environments, could provide new insights into A. baumannii pathogenesis. LysR-type transcriptional regulators (LTTRs) are structurally conserved among bacterial species and regulate virulence in many pathogens. We identified a novel LTTR, designated as LeuO encoded in the A. baumannii genome. After construction of LeuO mutant strain, transcriptome analysis showed that LeuO regulates the expression of 194 upregulated genes and 108 downregulated genes responsible for various functions and our qPCR validation of several differentially expressed genes support transcriptome data. Our results demonstrated that disruption of LeuO led to increased biofilm formation and increased pathogenicity in an animal model. However, the adherence and surface motility of the LeuO mutant were reduced compared with those of the wild-type strain. We observed some mutations on amino acids sequence of LeuO in clinical isolates. These mutations in the A. baumannii biofilm regulator LeuO may cause hyper-biofilm in the tested clinical isolates. This study is the first to demonstrate the association between the LTTR member LeuO and virulence traits of A. baumannii.}, } @article {pmid34707212, year = {2021}, author = {Kohno, T and Kitagawa, H and Tsuboi, R and Nishimura, Y and Imazato, S}, title = {Establishment of novel in vitro culture system with the ability to reproduce oral biofilm formation on dental materials.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {21188}, pmid = {34707212}, issn = {2045-2322}, mesh = {Adult ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; *Bioreactors ; Female ; Glass Ionomer Cements/chemistry/*pharmacology ; Humans ; Male ; Microbiological Techniques/instrumentation/methods ; Saliva/microbiology ; Zinc/chemistry/pharmacology ; }, abstract = {Intensive research has been conducted with the aim of developing dental restorative/prosthetic materials with antibacterial and anti-biofilm effects that contribute to controlling bacterial infection in the oral cavity. In situ evaluations were performed to assess the clinical efficacy of these materials by exposing them to oral environments. However, it is difficult to recruit many participants to collect sufficient amount of data for scientific analysis. This study aimed to assemble an original flow-cell type bioreactor equipped with two flow routes and assess its usefulness by evaluating the ability to reproduce in situ oral biofilms formed on restorative materials. A drop of bacterial suspension collected from human saliva and 0.2% sucrose solution was introduced into the assembled bioreactor while maintaining the incubation conditions. The bioreactor was able to mimic the number of bacterial cells, live/dead bacterial volume, and volume fraction of live bacteria in the in situ oral biofilm formed on the surface of restorative materials. The usefulness of the established culture system was further validated by a clear demonstration of the anti-biofilm effects of a glass-ionomer cement incorporating zinc-releasing glasses when evaluated by this system.}, } @article {pmid34707003, year = {2021}, author = {She, P and Zhou, L and Li, S and Zeng, X and Wu, Y}, title = {Inhibitory effects of 1,3-diaminopropane on the biofilm formation of Pseudomonas aeruginosa via interaction with quorum sensing system.}, journal = {Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences}, volume = {46}, number = {9}, pages = {942-948}, doi = {10.11817/j.issn.1672-7347.2021.200810}, pmid = {34707003}, issn = {1672-7347}, support = {82072350//the National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/pharmacology ; Biofilms ; Diamines ; Molecular Docking Simulation ; *Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {OBJECTIVES: To study the inhibitory effects of 1,3-diaminopropane on the biofilm formation of Pseudomonas aeruginosa and the underlying mechanisms.

METHODS: The experiment was divided into an experimental group and a control group. Crystal violet staining was used to examine the inhibitory effects of 1,3-diaminopropane on the biofilm formation of Pseudomonas aeruginosa, and the biofilm formation was compared between the 2 groups.Initial adherence inhibition assay and swimming plate assay were used to determine the inhibitory effects of 1,3-diaminopropane on the initial adherence and swimming motility of Pseudomonas aeruginosa,and the quantification of adhered cells and swimming diameter were compared between the 2 groups. Meanwhile, Western blotting was used to detect the Flagellin production of Pseudomonas aeruginosa; real-time RT-PCR was used to detect the quorum sensing system relative genes and flagellum regulative related genes expression in the 2 groups. Finally, molecular docking assay was used to calculate the interaction between 1,3-diaminopropane and LasI.

RESULTS: Compared with the control group, the biofilm formation of Pseudomonas aeruginosa was significantly inhibited in the experimental group in a dose-dependent manner (t=6.07, P<0.01).Compared with the control group, the initial adherence of Pseudomonas aeruginosa could significantly inhibit from (0.890±0.389)×10[6] to (0.245±0.076)×10[6] CFU/mL (t=3.257, P<0.05) in the experimental group (2.0 mmol/L).Compared with the control group, the swimming motility of Pseudomonas aeruginosa flagellar mediation could also inhibit in the experimental group (2.0 mmol/L). The swimming motility diameter was from (1.840±0.144) to (0.756±0.222) cm (t=7.099, P<0.01). Compared with the control group, the Flagellin production was inhibited in the experimental group. Finally, the molecular docking assay showed that the potential target of 1,3-diaminopropane was LasI.

CONCLUSIONS: 1,3-diaminopropane can significantly inhibit the biofilm formation of Pseudomonas aeruginosa, which potentially targets LasI protein.}, } @article {pmid34706512, year = {2021}, author = {Cheng, YG and Xin, PJ and Su, J}, title = {[Study on the effect of slightly acid hypochlorous water on dental unit waterlines biofilm model].}, journal = {Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]}, volume = {55}, number = {10}, pages = {1245-1249}, doi = {10.3760/cma.j.cn112150-20210329-00310}, pmid = {34706512}, issn = {0253-9624}, support = {TG‑2015‑009//Beijing health science and technology achievement and suitable technology promotion project-The application and promotion of water infection control technology in dental units with independent water supply/ ; }, mesh = {Biofilms ; Colony Count, Microbial ; *Equipment Contamination ; Humans ; *Water ; Water Microbiology ; }, abstract = {Pseudomonas aeruginosa biofilm was established on PU and PVC's surface by Center of Disease Control (CDC) Biofilm Reactor, to evaluate the effectiveness of Slightly Acidic Hypochlorous water (SAHW) for removing Pseudomonas aeruginosa biofilm on Polyurethane (PU) or Polyvinyl Chloride (PVC), which are commonly used in dental unit waterlines (DUWL). The biofilms were treated with 10 mg/L SAHW, 40 mg/L SAHW and sterile distilled water (control group) by the continuous immersion method for 3, 7, and 10 days. The total viable count (TVC) and Confocal laser scanning microscopy (CLSM) were selected to evaluate the biofilm removal effect and calculate the biofilm reduction rate. The results of TVC showed that 99%-100% biofilm reduction could be achieved in 10 mg/L SAHW group and 40 mg/L SAHW group. The results of CLSM showed that 10 mg/L SAHW group and 40 mg/L SAHW group could reach 89%-100% biofilm reduction after 10 days of treatment.}, } @article {pmid34705248, year = {2022}, author = {Ni, K and Cai, D and Lu, J and Tian, J}, title = {Eugenol-Mediated Inhibition of Biofilm Formed by S. aureus: a Potent Organism for Pediatric Digestive System Diseases.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {3}, pages = {1340-1358}, pmid = {34705248}, issn = {1559-0291}, mesh = {*Staphylococcus aureus ; }, abstract = {Ocimum tenuiflorum (KT) is a common ethnobotanical plant of Southeast Asia. The ethnic communities of these regions use the various parts of the plants, especially the leaves, for the treatment of various ailments like cold and flu, chronic infections, and surface ailments. The leaves of these plants are consumed to act as immune boosters in the body. With this ethnical background, we performed the antimicrobial and antibiofilm potential of the methanolic extract of Ocimum tenuiflorum against biofilm formed by S. aureus biofilm. The biofilm formed by S. aureus is a potent cause for the development of gastrointestinal (GI)-associated chronic infection. The extract from the KT leaf was analyzed using UV spectroscopy and HPLC to confirm the presence of the active ingredients present within the extract. The HPLC and GC-MS studies revealed the presence of eugenol and linalool in a greater proportion having the maximum drug-like properties. It was observed that KT showed maximum inhibition of biofilms, proteins, and carbohydrates being present with the extracellular polymeric substance (EPS). Interestingly, the maximum inhibition to the quorum sensing (QS) and the genomic DNA, RNA content was reduced by eugenol and linalool in comparison to the plant extract. The studies were supported by in silico interaction between eugenol and linalool with the QS proteins of S. aureus. The studies were further confirmed with microscopic studies SEM and FCM. The IR studies also confirmed much reduction in biofilm when treated with eugenol, linalool, and KT with respect to the untreated sample.}, } @article {pmid34705178, year = {2021}, author = {Grigorova, EV and Nemchenko, UM and Voropaeva, NM and Belkova, NL and Noskova, OA and Savilov, ED}, title = {Effect of Disinfectants with Different Active Ingredients on Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Bulletin of experimental biology and medicine}, volume = {171}, number = {6}, pages = {745-749}, pmid = {34705178}, issn = {1573-8221}, mesh = {Adolescent ; Bacterial Load ; Biofilms/*drug effects/growth & development ; Child ; Child, Preschool ; Culture Media/chemistry/pharmacology ; Disinfectants/*pharmacology ; Dose-Response Relationship, Drug ; Female ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Oxidants/*pharmacology ; Pseudomonas Infections/microbiology/pathology ; Pseudomonas aeruginosa/*drug effects/enzymology/growth & development/isolation & purification ; Quaternary Ammonium Compounds/*pharmacology ; Sepsis/microbiology/pathology ; }, abstract = {We compared the effects of disinfectants on biofilms of 10 Pseudomonas aeruginosa strains isolated from different loci of patients with purulent-septic infections. Identification was carried out by standard bacteriological methods. To substantiate the prospects of using in hospitals and to assess the effect of disinfectants on P. aeruginosa biofilms, the following disinfectants were used in various concentrations: Sekusept Aktiv, A-DEZ, and Monitor Oxy. All clinical strains of P. aeruginosa showed the ability to form biofilms. Both oxygen-containing and quaternary ammonium compounds effectively inhibited the formation of biofilms. In more than 50% cases, disinfectants with different active ingredients did not destroy pre-formed of P. aeruginosa biofilms.}, } @article {pmid34705176, year = {2021}, author = {Cherepushkina, VS and Mironova, TE and Afonyushkin, VN and Koptev, VY and Nefedova, EV and Donchenko, NA and Dimova, AS}, title = {Study of the Dynamics of Biofilm Formation and Elastase Activity of Pseudomonas aeruginosa in the Presence of Dodecanoyl-Homoserine Lactone.}, journal = {Bulletin of experimental biology and medicine}, volume = {171}, number = {6}, pages = {741-744}, pmid = {34705176}, issn = {1573-8221}, mesh = {4-Butyrolactone/*analogs & derivatives/biosynthesis/pharmacology ; Bacterial Load ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects/growth & development ; Culture Media/chemistry/pharmacology ; Dose-Response Relationship, Drug ; Homoserine/*analogs & derivatives/biosynthesis/pharmacology ; Pancreatic Elastase/*metabolism ; Pseudomonas aeruginosa/*drug effects/enzymology/growth & development ; Quorum Sensing/physiology ; }, abstract = {We studied the effect of early accumulation of N-3-oxo-dodecanoyl-homoserine lactone on the suppression of Pseudomonas aeruginosa reproduction, biofilm formation, and elastase activity. N-3-oxo-dodecanoyl-homoserine lactone in various concentrations was added to the P. aeruginosa culture, and changes in the concentration of bacteria and the formation of biofilms were studied in dynamics. N-3-oxo-dodecanoyl-homoserine lactone in a concentration of 25 μM, decelerated proliferation of bacterial cells during the first 6 h of culturing (p<0.05) and stimulated biofilm formation after 18 h of culturing. Elastase activity of P. aeruginosa increased significantly after addition of N-3-oxo-dodecanoyl-homoserine lactone in a concentration of 0.75 μM.}, } @article {pmid34705131, year = {2022}, author = {Qasemi, A and Rahimi, F and Katouli, M}, title = {Genetic diversity and virulence characteristics of biofilm-producing uropathogenic Escherichia coli.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {2}, pages = {297-307}, pmid = {34705131}, issn = {1618-1905}, support = {97014845//iran national science foundation, tehran, iran/ ; }, mesh = {Biofilms ; *Escherichia coli Infections/epidemiology ; Genetic Variation ; Humans ; Phylogeny ; *Urinary Tract Infections/microbiology ; *Uropathogenic Escherichia coli/genetics ; Virulence/genetics ; }, abstract = {Uropathogenic E. coli (UPEC) strains exhibit different levels of biofilm formation that help adhesion of the bacteria to uroepithelial cells. We investigated the genetic diversity and virulence-associated genes (VAGs) of biofilm-producing UPEC. A collection of 107 biofilm-producing (BFP) UPEC strains isolated from patients with UTI in Iran were divided into three groups of strong, moderate, and weak BFPs after a quantitative microtiter plate assay, and the involvement of curli and cellulose in adhesion of the strains to T24 cell line was confirmed by the construction of csgD and yedQ mutants of two representative UPEC strains. BFP strains were tested for their genetic diversity, phylogenetic groups, and the presence of 15 VAGs. A significant decrease in adhesion of csgD and yedQ mutant strains confirmed the role of biofilm production in adhesion to uroepithelial cells. A high diversity was found among all three groups of strong (Di = 0.998), moderate (Di = 0.998), and weak (Di = 0.988) BFPs with majority of the strains belonging to phylogroups B2 (44.9%) and A (24.3%). Strong BFP strains carried significantly higher level papEF, hlyA, and iutA than other BFP groups. In contrast, the presence of fimH, focG, sfaS, set-1, and cvaC was more pronounced among weak BFP strains. There exists a high genetic diversity among the BFP strains with different VGA profiles. However, the high prevalence of phylogroup A among BFP strains suggests the fitness of commensal E. coli strains to cause UTI in this country.}, } @article {pmid34704807, year = {2021}, author = {Gomes Von Borowski, R and Chat, S and Schneider, R and Nonin-Lecomte, S and Bouaziz, S and Giudice, E and Rigon Zimmer, A and Baggio Gnoatto, SC and Macedo, AJ and Gillet, R}, title = {Capsicumicine, a New Bioinspired Peptide from Red Peppers Prevents Staphylococcal Biofilm In Vitro and In Vivo via a Matrix Anti-Assembly Mechanism of Action.}, journal = {Microbiology spectrum}, volume = {9}, number = {2}, pages = {e0047121}, pmid = {34704807}, issn = {2165-0497}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Capsicum/*chemistry ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/physiology ; Microbial Sensitivity Tests ; Peptides/chemistry/*pharmacology ; Staphylococcal Infections/microbiology ; }, abstract = {Staphylococci are pathogenic biofilm-forming bacteria and a source of multidrug resistance and/or tolerance causing a broad spectrum of infections. These bacteria are enclosed in a matrix that allows them to colonize medical devices, such as catheters and tissues, and that protects against antibiotics and immune systems. Advances in antibiofilm strategies for targeting this matrix are therefore extremely relevant. Here, we describe the development of the Capsicum pepper bioinspired peptide "capsicumicine." By using microbiological, microscopic, and nuclear magnetic resonance (NMR) approaches, we demonstrate that capsicumicine strongly prevents methicillin-resistant Staphylococcus epidermidis biofilm via an extracellular "matrix anti-assembly" mechanism of action. The results were confirmed in vivo in a translational preclinical model that mimics medical device-related infection. Since capsicumicine is not cytotoxic, it is a promising candidate for complementary treatment of infectious diseases. IMPORTANCE Pathogenic biofilms are a global health care concern, as they can cause extensive antibiotic resistance, morbidity, mortality, and thereby substantial economic loss. So far, no effective treatments targeting the bacteria in biofilms have been developed. Plants are constantly attacked by a wide range of pathogens and have protective factors, such as peptides, to defend themselves. These peptides are common components in Capsicum baccatum (red pepper). Here, we provide insights into an antibiofilm strategy based on the development of capsicumicine, a natural peptide that strongly controls biofilm formation by Staphylococcus epidermidis, the most prevalent pathogen in device-related infections.}, } @article {pmid34704380, year = {2022}, author = {Leung, K and Bi, J and Giannelis, G and Owen, G and Larjava, H}, title = {Decontamination of multispecies oral biofilm from rough implant surface by airflow with glycine.}, journal = {Clinical and experimental dental research}, volume = {8}, number = {1}, pages = {322-328}, pmid = {34704380}, issn = {2057-4347}, support = {//University of British Columbia/ ; }, mesh = {Biofilms ; Decontamination ; *Dental Implants/microbiology ; Glycine/pharmacology ; Surface Properties ; }, abstract = {OBJECTIVES: Decontamination of biofilm-colonized rough implant surfaces remains challenging. We investigated the effect of airflow with glycine powder (AFG) on decontamination of mature oral multispecies biofilm from a sandblasted and acid etched (SLA) titanium surface.

MATERIALS AND METHODS: Subgingival dental plaque was cultured on SLA disks anaerobically for 21 days. AFG with various settings and distances was applied directly on the disks with or without previous rinse of 0.9% NaCl. The specimens were then analyzed through scanning electron microscope and remaining bacteria on the implant surface were quantified and statistically compared.

RESULTS: Mature oral biofilm with cocci and rods as major morphotypes, as well as spiral- and filamentous-shaped organisms, was formed on the untreated disks. Saline rinsing removed the thick biofilm layer but left numerous of coccoid bacteria in rough surface pits. AFG effectively removed most of the bacteria from the pits. Both 25% and 50% power settings were equally effective at 3-mm distance. With 50% power, AFG successfully removed bacteria at both 3- and 6-mm distance. When AFG was applied on native biofilm without prior rinsing with saline, it effectively removed the biofilm including bacteria in the pits.

CONCLUSION: Application of AFG appears effective in removing bacteria from rough implant surfaces.}, } @article {pmid34699600, year = {2021}, author = {Knapp, PW and Chen, Z and Scuderi, GR and Mont, MA}, title = {Protocols for the Use of a Novel Biofilm-Disrupting Wound Irrigation Solution for Prevention of Surgical-Site Infections After Total Joint Arthroplasty.}, journal = {Surgical technology international}, volume = {39}, number = {}, pages = {405-411}, doi = {10.52198/21.STI.39.OS1514}, pmid = {34699600}, issn = {1090-3941}, mesh = {Arthroplasty ; *Biofilms ; Humans ; *Surgical Wound Infection/prevention & control ; Therapeutic Irrigation ; }, abstract = {Surgical-site infections are potential complications of total joint arthroplasties. Many strategies, ranging from preoperative to postoperative, have been developed in an attempt to mitigate this morbidity. Biofilms have been implicated in difficulties of treatment. Therefore, antimicrobials have been increasingly used to combat these problems. In this report, we will summarize different protocols which utilize a new antimicrobial solution. Providing surgeons with an effective prevention option for these infections is crucial for positive outcomes and the continued advancement in the practice of total joint arthroplasty.}, } @article {pmid34699306, year = {2021}, author = {Wang, H and Bu, L and Shu, F and Bai, Y and Xue, F and Shi, S and Sun, D}, title = {Molecular Mechanism of Biofilm Locator Protein Kinase Dbf2p-related kinase 1 in Regulating Innate Immune Response to Interleukin 17-induced Viral Pneumonia.}, journal = {Bioengineered}, volume = {12}, number = {2}, pages = {10335-10344}, pmid = {34699306}, issn = {2165-5987}, mesh = {Animals ; Biofilms/*growth & development ; Cell Proliferation ; Chemokines/metabolism ; *Immunity, Innate ; Inflammation/pathology ; Interleukin-17/*metabolism ; Mice ; Pneumonia, Viral/*enzymology/*immunology ; Protein Serine-Threonine Kinases ; RAW 264.7 Cells ; Respiratory Syncytial Virus Infections/immunology/virology ; Respiratory Syncytial Viruses/physiology ; Signal Transduction ; }, abstract = {It focused on the antiviral immune regulation of biofilm-localized protein kinase Dbf2p-related kinase 1 (NDR1) in viral pneumonia. Mouse alveolar monocyte RAW264.7 was used as blank control, and viral pneumonia cell model was prepared by infecting cells with respiratory syncytial virus (RSV). NDR1 overexpression vector and siRNA interference sequences were synthesized, and overexpression/silence NDR1 cell model was fabricated. About 50 ng/mL interleukin 17 (IL-17) was given to stimulate. Enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcription PCR (RT-qRCR), and Western blot were performed to detect cytokines and chemokines, mRNA of inflammatory factors, and signal molecule protein expression. Notably, RSV infection increased RSV-F mRNA in RAW264.7 cells and reduced NDR1 mRNA and protein. Secretion levels of IL-6, interferon β (IFN-β), chemokine (C-X-C motif) ligand 2 (CXCL2), and chemokine (C-C motif) ligand 2 (CCL20) increased in the model group versus blank control (P< 0.05). IL-6, IFN-β, tumor necrosis factor α (TNF-α), and toll-like receptor 3 (TLR3) mRNA were up-regulated (P < 0.05). Extracellular signal-regulated kinase (ERK1/2), p38 protein phosphorylation, human recombinant 1 (TBK1), and nuclear factor kappa-B (NF-κB) protein levels increased (P < 0.05). After overexpression of NDR1, the secretion levels of cytokines and chemokines, inflammatory factors mRNA, and signal molecule protein increased significantly. After NDR1 was silenced, cytokines and chemokines, inflammatory factors mRNA, and signal molecule protein were not significantly different versus blank control group (P > 0.05). In short, NDR1 regulated innate immune response to viral pneumonia induced by IL-17, which can be used as a new target for the treatment of IL-17-induced inflammatory response and autoimmune diseases.}, } @article {pmid34699244, year = {2021}, author = {Zhang, Z and Lu, T and Yang, D and Lu, S and Cai, R and Tan, W}, title = {A High-Wet-Strength Biofilm for Readable and Highly Sensitive Humidity Sensors.}, journal = {Nano letters}, volume = {21}, number = {21}, pages = {9030-9037}, doi = {10.1021/acs.nanolett.1c02452}, pmid = {34699244}, issn = {1530-6992}, mesh = {Biofilms ; *Cellulose/chemistry ; Humidity ; *Water/chemistry ; }, abstract = {Low-cost and flexible biofilm humidity sensors with good wet strength are crucial for humidity detection. However, it remains a great challenge to integrate good reversibility, rapid humidity response, and robust humid mechanical strength in one sensor. In this respect, we report a facile method to prepare a sustainable biofilm (named MC film) from sisal cellulose microcrystals (MSF-g-COOH) and citric acid (CA). After cross-linking with CA, the MC film exhibits excellent wet strength and rapid humidity response. More importantly, MC film can be used over a wide temperature range with excellent durability and reversibility for humidity detection. A highly sensitive humidity sensor fabricated from the MC film exhibits high reversibility and excellent water resistance and can be applied in humidity and personalized breath health monitoring. Our work fills the gap between biomaterial design and high-performance sensing devices.}, } @article {pmid34699005, year = {2022}, author = {Li, X and Zhao, J and Zhang, Y and He, J and Ma, K and Liu, C}, title = {Role of organic/sulfide ratios on competition of DNRA and denitrification in a co-driven sequencing biofilm batch reactor.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {13}, pages = {18793-18804}, pmid = {34699005}, issn = {1614-7499}, support = {51808045//Natural Science Foundation of China/ ; 51178007//Natural Science Foundation of China/ ; 2019JQ-686//Shannxi Provincial Science and Technology Planning Project/ ; 212300410179//Henan Natural Science Foundation/ ; }, mesh = {*Ammonium Compounds/metabolism ; Biofilms ; Denitrification ; Humans ; *Nitrates/metabolism ; Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S/metabolism ; Sulfides ; }, abstract = {Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two competing pathways in nitrate-reducing process. In this study, a series of C/S ratios from 8:1 to 2:4 were investigated in a sequencing biofilm batch reactor (SBBR) to determine the role of reducers (sulfide and acetate) on their competition. The results showed that the proportion of DNRA increased in high electron system, either in organic-rich system or in sulfide-rich system. The highest DNRA ratio increased to 16.4% at the C/S ratio of 2:3. Excess electron donors, particularly sulfide, were favorable for DNRA in a limited nitrate environment. Moreover, a higher reductive environment could facilitate DNRA, especially, when ORP was lower than - 400 mV in this system. 16S rRNA gene sequencing analysis demonstrated that Geobacter might be the important participant involved in DNRA process in organic-rich system, while Desulfomicrobium might be the dominant DNRA bacteria in sulfide-rich system. DNRA cultivation could enrich nitrogen conversion pathways in conventional denitrification systems and deepen the insight into nitrogen removal at low C/N.}, } @article {pmid34698719, year = {2021}, author = {D'Ercole, S and Di Campli, E and Pilato, S and Iezzi, G and Cellini, L and Piattelli, A and Petrini, M}, title = {Streptococcus oralis Biofilm Formation on Titanium Surfaces.}, journal = {The International journal of oral & maxillofacial implants}, volume = {36}, number = {5}, pages = {929-936}, doi = {10.11607/jomi.8739}, pmid = {34698719}, issn = {1942-4434}, mesh = {Biofilms ; *Dental Implants ; Microscopy, Electron, Scanning ; *Streptococcus oralis ; Surface Properties ; Titanium ; }, abstract = {PURPOSE: The aim of this study was to compare the Streptococcus oralis biofilm formation on titanium machined turned surfaces and sandblasted surfaces that were previously characterized for their superficial topographies.

MATERIALS AND METHODS: Two commercially pure titanium surfaces were analyzed and compared: machined (turned surfaces subjected to a process of decontamination that also included a double acid attack) and sandblasted (sandblasted surfaces, cleaned with purified water, enzymatic detergent, acetone, and alcohol). The characterization of the samples at the nanolevel was performed using atomic force microscopy, which permitted calculation of the superficial nanoroughness (Ra). The sessile drop method was used to measure the water contact angle in both groups and allowed information to be gained about their wetting properties. Scanning electron microscope and energy-dispersive x-ray spectroscopy analysis allowed comparison of the microtopographic geometry and the chemical composition of the samples. Then, the disks were pre-incubated with saliva in order to form an acquired pellicle. Streptococcus oralis was put on the disks, and both groups were tested at 24 and 48 hours for biofilm biomass evaluation, colony-forming units (CFUs), and live/dead staining for cell viability.

RESULTS: The sandblasted samples were characterized by a significantly higher level of superficial oxides, superficial roughness, and hydrophilicity, compared with the machined turned samples. Although there were topographic differences, the Streptococcus oralis biofilm formation, quantified in CFUs, and biomass formation at 24 and 48 hours were similar in both groups. With the live/dead staining, the sandblasted disks were characterized by an increased percentage of dead cells compared with the machined disks.

CONCLUSION: Although significant topographic differences were present between machined and sandblasted disks, the Streptococcus oralis biofilm formation seems to not be significantly affected.}, } @article {pmid34698369, year = {2022}, author = {Zhao, W and Gao, Y and Zhao, Y and Deng, X and Shao, J and Chen, S}, title = {Impact of anodophilic biofilm bioelectroactivity on the denitrification behavior of air-cathode microbial fuel cells.}, journal = {Biotechnology and bioengineering}, volume = {119}, number = {1}, pages = {268-276}, doi = {10.1002/bit.27972}, pmid = {34698369}, issn = {1097-0290}, mesh = {Air ; Bioelectric Energy Sources/*microbiology ; *Biofilms ; Denitrification/*physiology ; Electrodes/microbiology ; }, abstract = {Generally, high bioelectroactivity of anodophilic biofilm favors high power generation of microbial fuel cell (MFC); however, it is not clear whether it can promote denitrification of MFC synchronously. In this study, we studied the impact of anodophilic biofilm bioelectroactivity on the denitrification behavior of air-cathode MFC (AC-MFC) in steady state and found that high bioelectroactivity of anodophilic biofilm not only favored high power generation of the AC-MFC, but also promoted the growth of denitrifers at the anodes and strengthened denitrification. Anodophilic biofilms of AC-MFC with various bioelectroactivity were acclimated at conditions of open circuit (OC), Rext of 1000 Ω and 20 Ω (denoted as AC-MFC-OC, AC-MFC-1000Ω, and AC-MFC-20Ω, respectively) and performed for over 100 days. Electrochemical tests and microbial analysis results showed that the anode of the AC-MFC-20Ω delivered higher current response of both oxidation and denitrification and had higher abundance of electroactive bacteria than the AC-MFC-OC, AC-MFC-1000Ω, demonstrating a higher bioelectroactivity of the anodophilic biofilms. Moreover, these electroactive bacteria favored the accumulation of denitrifers, like Thauera and Alicycliphilus, probably by consuming trace oxygen through catalyzing oxygen reduction. The AC-MFC-20Ω not only delivered a 61.7% higher power than the AC-MFC-1000Ω, but also achieved a stable and high denitrification rate constant (kDN) of 1.9 h[-1] , which was 50% and 40% higher than that of the AC-MFC-OC and AC-MFC-1000Ω, respectively. It could be concluded that the high bioelectroactivity of the anodophilic biofilms not only favored high power generation of the AC-MFC, but also promoted the enrichment of denitrifers at the anodes and strengthened denitrification. This study provided an effective method for enhancing power generation and denitrification performance of the AC-MFC synchronously.}, } @article {pmid34696328, year = {2021}, author = {Van Nieuwenhuyse, B and Galant, C and Brichard, B and Docquier, PL and Djebara, S and Pirnay, JP and Van der Linden, D and Merabishvili, M and Chatzis, O}, title = {A Case of In Situ Phage Therapy against Staphylococcus aureus in a Bone Allograft Polymicrobial Biofilm Infection: Outcomes and Phage-Antibiotic Interactions.}, journal = {Viruses}, volume = {13}, number = {10}, pages = {}, pmid = {34696328}, issn = {1999-4915}, mesh = {Allografts/drug effects/*microbiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms ; Bone and Bones/drug effects/*microbiology/pathology ; Child ; Coinfection/*therapy ; Drug Interactions ; Female ; Humans ; Phage Therapy/*methods ; Sarcoma, Ewing/drug therapy ; Staphylococcal Infections/diagnosis/*therapy ; Staphylococcus Phages/*physiology ; Staphylococcus aureus/*drug effects ; }, abstract = {Phage therapy (PT) shows promising potential in managing biofilm infections, which include refractory orthopedic infections. We report the case of a 13-year-old girl who developed chronic polymicrobial biofilm infection of a pelvic bone allograft after Ewing's sarcoma resection surgery. Chronic infection by Clostridium hathewayi, Proteus mirabilis and Finegoldia magna was worsened by methicillin-susceptible Staphylococcus aureus exhibiting an inducible Macrolides-Lincosamides-Streptogramin B resistance phenotype (iMLSB). After failure of conventional conservative treatment, combination of in situ anti-S. aureus PT with surgical debridement and intravenous antibiotic therapy led to marked clinical and microbiological improvement, yet failed to prevent a recurrence of infection on the midterm. This eventually led to surgical graft replacement. Multiple factors can explain this midterm failure, among which incomplete coverage of the polymicrobial infection by PT. Indeed, no phage therapy against C. hathewayi, P. mirabilis or F. magna could be administered. Phage-antibiotic interactions were investigated using OmniLog[®] technology. Our results suggest that phage-antibiotic interactions should not be considered "unconditionally synergistic", and should be assessed on a case-by-case basis. Specific pharmacodynamics of phages and antibiotics might explain these differences. More than two years after final graft replacement, the patient remains cured of her sarcoma and no further infections occurred.}, } @article {pmid34695514, year = {2022}, author = {Engloner, AI and Németh, K and Óvári, M}, title = {Significant impact of seasonality, verticality and biofilm on element accumulation of aquatic macrophytes.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {292}, number = {Pt B}, pages = {118402}, doi = {10.1016/j.envpol.2021.118402}, pmid = {34695514}, issn = {1873-6424}, mesh = {Biodegradation, Environmental ; Biofilms ; Plants ; *Trace Elements/analysis ; *Water Pollutants, Chemical/analysis ; }, abstract = {Submersed macrophytes accumulate large amounts of macro- and trace elements from the environment and, therefore, are frequently used as indicators of water pollution and tools to remove pollutants from contaminated waters. This study provides evidences that the quantity of macro- and trace elements accumulated in the macrophyte Ceratophyllum demersum depends strongly on the seasonality, on the vertical position of the plant material and on the biofilm cover. Element contents of macrophytes with and without biofilm cover and that of vertical plant sections were investigated by an ICP-MS technique in three different habitats, at the beginning and at the end of the vegetation period. Results demonstrated that the element concentrations of Ceratophyllum demersum dropped to one-half and one-eighth by the end of the summer; and the amount of certain elements in the lower part of plants were up to six times higher than in the upper and in plants with well-developed epiphytic microbial community 2-5-fold higher than in plants without biofilm. These results help in phytoremediation practice and in setting up future biomonitoring studies. When it is necessary to calculate the exact amount of elements which can be accumulated by plants in a polluted environment or should be removed from a contaminated water by harvesting macrophytes, it is of high importance to consider the month of the study, the plant parts harvested and the biofilm cover.}, } @article {pmid34694901, year = {2022}, author = {Katharios-Lanwermeyer, S and Koval, SA and Barrack, KE and O'Toole, GA}, title = {The Diguanylate Cyclase YfiN of Pseudomonas aeruginosa Regulates Biofilm Maintenance in Response to Peroxide.}, journal = {Journal of bacteriology}, volume = {204}, number = {1}, pages = {e0039621}, pmid = {34694901}, issn = {1098-5530}, support = {R01 GM123609/GM/NIGMS NIH HHS/United States ; R37 AI083256/AI/NIAID NIH HHS/United States ; R37 AI83256/NH/NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/growth & development ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/*drug effects ; Gene Expression Regulation, Enzymologic/*drug effects ; Hydrogen Peroxide/*pharmacology ; Microbial Viability/drug effects ; Mutation ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; Pseudomonas aeruginosa/drug effects/*enzymology ; }, abstract = {Pseudomonas aeruginosa forms surface-attached communities that persist in the face of antimicrobial agents and environmental perturbation. Published work has found that extracellular polysaccharide (EPS) production, regulation of motility, and induction of stress response pathways contribute to biofilm tolerance during such insults. However, little is known regarding the mechanism(s) whereby biofilm maintenance is regulated when exposed to such environmental challenges. Here, we provide evidence that the diguanylate cyclase YfiN is important for the regulation of biofilm maintenance when exposed to peroxide. We find that compared to the wild type (WT), static biofilms of the ΔyfiN mutant exhibit a maintenance defect, which can be further exacerbated by exposure to peroxide (H2O2); this defect can be rescued through genetic complementation. Additionally, we found that the ΔyfiN mutant biofilms produce less c-di-GMP than WT and that H2O2 treatment enhanced motility of surface-associated bacteria and increased cell death for the ΔyfiN mutant grown as a biofilm compared to WT biofilms. These data provide evidence that YfiN is required for biofilm maintenance by P. aeruginosa, via c-di-GMP signaling, to limit motility and protect viability in response to peroxide stress. These findings add to the growing recognition that biofilm maintenance by P. aeruginosa is an actively regulated process that is controlled, at least in part, by the wide array of c-di-GMP metabolizing enzymes found in this microbe. IMPORTANCE We build on previous findings that suggest that Pseudomonas aeruginosa utilizes c-di-GMP metabolizing enzymes to actively maintain a mature biofilm. Here, we explore how the diguanylate cyclase YfiN contributes to the regulation of biofilm maintenance during peroxide exposure. We find that mature P. aeruginosa biofilms require YfiN to synthesize c-di-GMP, regulate motility, and ensure viability during peroxide stress. These findings provide further evidence that the modulation of c-di-GMP in response to environmental signals is an important mechanism by which biofilms are maintained.}, } @article {pmid34694882, year = {2022}, author = {Sindeldecker, D and Prakash, S and Stoodley, P}, title = {Exploration of the Pharmacodynamics for Pseudomonas aeruginosa Biofilm Eradication by Tobramycin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {1}, pages = {e0137121}, pmid = {34694882}, issn = {1098-6596}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R01 HL141941/HL/NHLBI NIH HHS/United States ; }, mesh = {Aminoglycosides ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; *Tobramycin/pharmacology ; }, abstract = {Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen which is involved in numerous infections. It is of growing concern within the field of antibiotic resistance and tolerance and often exhibits multidrug resistance. Previous studies have shown the emergence of antibiotic-resistant and -tolerant variants within the zone of clearance of a biofilm lawn after exposure to aminoglycosides. As concerning as the tolerant variant emergence is, there was also a zone of killing (ZOK) immediately surrounding the antibiotic source from which no detectable bacteria emerged or were cultured. In this study, the ZOK was analyzed using both in vitro and in silico methods to determine if there was a consistent antibiotic concentration versus time constraint (area under the curve [AUC]) which is able to completely kill all bacteria in the lawn biofilms in our in vitro model. Our studies revealed that by achieving an average AUC of 4,372.5 µg·h/mL, complete eradication of biofilms grown on both agar and hydroxyapatite was possible. These findings show that appropriate antibiotic concentrations and treatment duration may be able to treat antibiotic-resistant and -tolerant biofilm infections.}, } @article {pmid34694768, year = {2021}, author = {Franklin, T and Wu, Y and Lang, J and Li, S and Yang, R}, title = {Design of Polymeric Thin Films to Direct Microbial Biofilm Growth, Virulence, and Metabolism.}, journal = {Biomacromolecules}, volume = {22}, number = {12}, pages = {4933-4944}, pmid = {34694768}, issn = {1526-4602}, support = {R21 DC019206/DC/NIDCD NIH HHS/United States ; }, mesh = {*Biofilms ; Polymers/metabolism ; *Pseudomonas aeruginosa/genetics ; Virulence ; Virulence Factors/metabolism ; }, abstract = {Biofilms are ubiquitous in nature, yet strategies to direct biofilm behavior without genetic manipulation are limited. Due to the small selection of materials that have been used to successfully grow biofilms, the availability of functional materials that are able to support growth and program microbial functions remains a critical bottleneck in the design and deployment of functional yet safe microbes. Here, we report the design of insoluble pyridine-rich polymer surfaces synthesized using initiated chemical vapor deposition, which led to modulated biofilm growth and virulence in Pseudomonas aeruginosa (PAO1). A variety of extracellular virulence factors exhibited decreased production in response to the functional polymer, most significantly biomolecules also associated with iron acquisition, validating the material design strategy reported here. This report signifies a rich potential for materials-based strategies to direct the behavior of naturally occurring biofilms, which complement the existing genetic engineering toolkits in advancing microbiology, translational medicine, and biomanufacturing.}, } @article {pmid34694672, year = {2021}, author = {Nsayef Muslim, S and Mohammed Ali, AN and Auda, IG}, title = {Anti-biofilm and anti-virulence effects of silica oxide nanoparticle-conjugation of lectin purified from Pseudomonas aeruginosa.}, journal = {IET nanobiotechnology}, volume = {15}, number = {3}, pages = {318-328}, pmid = {34694672}, issn = {1751-875X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Lectins/pharmacology ; *Nanoparticles ; Oxides ; *Pseudomonas aeruginosa ; Silicon Dioxide ; Virulence ; }, abstract = {Pseudomonas aeruginosa lectin is purified and nanoparticle-conjugated in an attempt to inhibit biofilm formation. Thirteen (23.6%) P. aeruginosa isolates are obtained from chicken meat samples, of which 30.8% are biofilm producers and 69.2% are lectin producers. Lectin is purified 36.8-fold to final specific activity of 506.9 U/mg. Four nanoparticle types are prepared via laser ablation: platinum (Pt), gold (Au), silica oxide (SiO2), and tin oxide (SnO2). The four types are characterised, and pulse feeding is used to conjugate the lectin and nanoparticles. Pt, Au, SiO2, and SnO2 nanoparticles inhibit biofilm formation, especially SiO2 nanoparticles, which have higher effectiveness when conjugated with purified lectin. SiO2 -conjugated lectin significantly (p < 0.05) inhibits biofilm formation more effectively than control and other nanoparticle-conjugated lectins. Au-, Pt nanoparticle-, and SnO2 -conjugated lectins inhibit biofilm significantly compared with control (p < 0.05), and rhlR gene expression is decreased in the presence of SiO2 -conjugated lectin. Furthermore, lectin and Pt, Au, SiO2 and SnO2 nanoparticles separately, and their conjugated lectins, are effective biofilm inhibitors. Of these, SiO2 -conjugated lectin was most significant as an anti-biofilm. Moreover, virulence factors regulon and RhlR were reduced by SiO2 -conjugated lectin, indicating that this conjugation may also decrease the virulence of P. aeruginosa.}, } @article {pmid34694502, year = {2022}, author = {Lavaee, F and Motamedifar, M and Rafiee, G}, title = {The effect of photodynamic therapy by gold nanoparticles on Streptococcus mutans and biofilm formation: an in vitro study.}, journal = {Lasers in medical science}, volume = {37}, number = {3}, pages = {1717-1725}, pmid = {34694502}, issn = {1435-604X}, support = {11909//Vice-Chancellor for Research, Shiraz University of Medical Sciences/ ; }, mesh = {Biofilms ; Gold/pharmacology ; *Metal Nanoparticles ; Methylene Blue/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Streptococcus mutans ; }, abstract = {In this experimental study, we aimed to evaluate the antibacterial and anti-biofilm effects of photodynamic therapy with a photosensitizer in conjunction with Gold nanoparticles against Streptococcus mutans as an important cariogenic bacterial agent. This experimental in vitro study evaluated the antibacterial and anti-biofilm effect of five groups as followed against S. mutans: methylene blue (MB), Gold nanoparticles (AuNPs), methylene blue conjugated with Gold nanoparticles (MB-AuNPs), MB mediated photodynamic therapy (MB mediated PDT) and methylene blue conjugated with Gold nanoparticles mediated photodynamic therapy (MB-AuNPs mediated PDT). InGaAlP laser (Azor-2 K) with 25 mW total output, 660 nm wavelength and laser probe cross-section of 0.78 cm[2] was used for methylene blue activation. Total dose of 19.23 J/cm[2] for 10 min was irradiated to each group. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and colony forming unit (CFU) were determined. Bacterial biofilm formation inhibition was assessed by crystal violet staining (The microtiter plate biofilm assay). The viability of S. mutans cells was assessed by MTT assay. MB mediated PDT and MB-AuNP mediated PDT were the most effective method for S. mutans biofilm inhibition (P < 0.05). MB alone, MB-AuNP alone and MB mediated PDT and MB-AuNP mediated PDT had the same effect against the planktonic phase of S. mutans (P > 0.05). Also they had similar pattern for bacterial growth inhibition and bactericidal effect (P > 0.05). Gold nano particle mediated photodynamic therapy represented antibacterial and antibiofilm activity against S. mutans; but this modality was not more effective than routine PDT.}, } @article {pmid34692562, year = {2021}, author = {Dhaliwal, JS and Abd Rahman, NA and Ming, LC and Dhaliwal, SKS and Knights, J and Albuquerque Junior, RF}, title = {Microbial Biofilm Decontamination on Dental Implant Surfaces: A Mini Review.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {736186}, pmid = {34692562}, issn = {2235-2988}, mesh = {*Anti-Infective Agents ; Biofilms ; Decontamination ; *Dental Implants ; Humans ; *Peri-Implantitis/prevention & control ; }, abstract = {INTRODUCTION: After insertion into the bone, implants osseointegrate, which is required for their long-term success. However, inflammation and infection around the implants may lead to implant failure leading to peri-implantitis and loss of supporting bone, which may eventually lead to failure of implant. Surface chemistry of the implant and lack of cleanliness on the part of the patient are related to peri-implantitis. The only way to get rid of this infection is decontamination of dental implants.

OBJECTIVE: This systematic review intended to study decontamination of microbial biofilm methods on titanium implant surfaces used in dentistry.

METHODS: The electronic databases Springer Link, Science Direct, and PubMed were explored from their inception until December 2020 to identify relevant studies. Studies included had to evaluate the efficiency of new strategies either to prevent formation of biofilm or to treat matured biofilm on dental implant surfaces.

RESULTS AND DISCUSSION: In this systematic review, 17 different groups of decontamination methods were summarized from 116 studies. The decontamination methods included coating materials, mechanical cleaning, laser treatment, photodynamic therapy, air polishing, anodizing treatment, radiation, sonication, thermal treatment, ultrasound treatment, chemical treatment, electrochemical treatment, antimicrobial drugs, argon treatment, and probiotics.

CONCLUSION: The findings suggest that most of the decontamination methods were effective in preventing the formation of biofilm and in decontaminating established biofilm on dental implants. This narrative review provides a summary of methods for future research in the development of new dental implants and decontamination techniques.}, } @article {pmid34692461, year = {2021}, author = {Suri, N and Yadav, C and Sandilya, S and Bhalodia, N}, title = {Salvaging Cochlear Implant After Suspected Biofilm Infection: Our Experience.}, journal = {Indian journal of otolaryngology and head and neck surgery : official publication of the Association of Otolaryngologists of India}, volume = {73}, number = {4}, pages = {499-503}, pmid = {34692461}, issn = {2231-3796}, abstract = {We describe a novel procedure using betaine surfactant and polyhexanide for biofilm in cochlear implants. Early intervention along with wound debridement, double layer vascularized flap and rifampicin helps in salvaging the implant. Leaving the array in cochlea avoids fibrosis and can be considered for cochlear implantation at a later stage. This novel procedure significantly limits morbidity and repeated surgeries.}, } @article {pmid34692212, year = {2021}, author = {Tran, VN and Saravana, PS and Park, S and Truong, VG and Chun, BS and Kang, HW}, title = {Opto-chemical treatment for enhanced high-level disinfection of mature bacterial biofilm in a Teflon-based endoscope model.}, journal = {Biomedical optics express}, volume = {12}, number = {9}, pages = {5736-5750}, pmid = {34692212}, issn = {2156-7085}, abstract = {Medical societies and public health agencies rigorously emphasize the importance of adequate disinfection of flexible endoscopes. The aim of this work was to propose a novel opto-chemical disinfection treatment against Staphylococcus aureus grown in mature biofilm on Teflon-based endoscope channel models. Laser irradiation using near-infrared and blue wavelengths combined with a low concentration of chemical disinfectant induced both irreversible thermal denaturation and intercellular oxidative stress as a combined mechanism for an augmented antimicrobial effect. The opto-chemical method yielded a 6.7-log10 reduction of the mature Staphylococcus aureus biofilms (i.e., approximately 1.0-log10 higher than current requirement of standard treatment). The proposed technique may be a feasible disinfection method for mitigating the risk associated with infection transmission.}, } @article {pmid34690995, year = {2021}, author = {Afroj, S and Brannen, AD and Nasrin, S and Al Mouslem, A and Hathcock, T and Maxwell, H and Rasmussen-Ivey, CR and Sandage, MJ and Davis, EW and Panizzi, P and Wang, C and Liles, MR}, title = {Bacillus velezensis AP183 Inhibits Staphylococcus aureus Biofilm Formation and Proliferation in Murine and Bovine Disease Models.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {746410}, pmid = {34690995}, issn = {1664-302X}, abstract = {The increasing frequency of S. aureus antimicrobial resistance has spurred interest in identifying alternative therapeutants. We investigated the S. aureus-inhibitory capacity of B. velezensis strains in mouse and bovine models. Among multiple B. velezensis strains that inhibited S. aureus growth in vitro, B. velezensis AP183 provided the most potent inhibition of S. aureus proliferation and bioluminescence in a mouse cutaneous wound (P = 0.02). Histology revealed abundant Gram-positive cocci in control wounds that were reduced in B. velezensis AP183-treated tissues. Experiments were then conducted to evaluate the ability of B. velezensis AP183 to prevent S. aureus biofilm formation on a tracheostomy tube substrate. B. velezensis AP183 could form a biofilm on a tracheostomy tube inner cannula substrate, and that this biofilm was antagonistic to S. aureus colonization. B. velezensis AP183 was also observed to inhibit the growth of S. aureus isolates originated from bovine mastitis cases. To evaluate the inflammatory response of mammary tissue to intramammary inoculation with B. velezensis AP183, we used high dose and low dose inocula in dairy cows. At the high dose, a significant increase in somatic cell count (SCC) and clinical mastitis was observed at all post-inoculation time points (P < 0.01), which resolved quickly compared to S. aureus-induced mastitis; in contrast, the lower dose of B. velezensis AP183 resulted in a slight increase of SCC and no clinical mastitis. In a subsequent experiment, all mammary quarters in four cows were induced to have grade 1 clinical mastitis by intramammary inoculation of a S. aureus mastitis isolate; following mastitis induction, eight quarters were treated with B. velezensis AP183 and milk samples were collected from pretreatment and post-treatment samples for 9 days. In groups treated with B. velezensis AP183, SCC and abundance of S. aureus decreased with significant reductions in S. aureus after 3 days post-inoculation with AP183 (P = 0.04). A milk microbiome analysis revealed significant reductions in S. aureus relative abundance in the AP183-treated group by 8 days post-inoculation (P = 0.02). These data indicate that B. velezensis AP183 can inhibit S. aureus biofilm formation and its proliferation in murine and bovine disease models.}, } @article {pmid34690617, year = {2021}, author = {Shahid, M and Naureen, I and Riaz, M and Anjum, F and Fatima, H and Rafiq, MA}, title = {Biofilm Inhibition and Antibacterial Potential of Different Varieties of Garlic (Allium sativum) Against Sinusitis Isolates.}, journal = {Dose-response : a publication of International Hormesis Society}, volume = {19}, number = {4}, pages = {15593258211050491}, pmid = {34690617}, issn = {1559-3258}, abstract = {Sinusitis or rhinosinusitis is inflammation of the paranasal sinuses which can be due to autoimmune, allergy, and infection problems. Current study was aimed to evaluate the antibiofilm and antibacterial potential of different varieties of A sativum. Four different varieties (China white, China pink, Desi white, and Desi pink) were used and extracted with methanol and water. Results of antioxidant analysis of A sativum extracts showed that all varieties of garlic have considerable quantity of flavonoids with significant DPPH inhibition and reductive potential. Antibacterial activity of A sativum extracts was tested against different Gram negative and Gram-positive sinusitis isolates. All the sinusitis isolates were susceptible to both methanolic and aqueous extracts of different varieties of A sativum with least MIC values. Antibiofilm potential of extracts against sinusitis isolates was evaluated through crystal violet assay, and all extracts of A sativum were significantly effective against destruction of microbial biofilm. In summary, A sativum extracts possess effective antibacterial and antibiofilm activity against sinusitis isolates and can be utilized for prevention of drug resistance against sinusitis infections and further evaluation is necessary.}, } @article {pmid34689231, year = {2022}, author = {Yang, J and Cheng, S}, title = {External resistance acclimation regulates bio-anode: new perspective from biofilm structure and its correlation with anode performance.}, journal = {Bioprocess and biosystems engineering}, volume = {45}, number = {2}, pages = {269-277}, pmid = {34689231}, issn = {1615-7605}, support = {no. 52070162//National Natural Science Foundation of China/ ; 51778562//National Natural Science Foundation of China/ ; 2018YFA0901300//National Key Research and Development Program of China/ ; }, mesh = {Acclimatization ; *Bioelectric Energy Sources ; Biofilms ; Biomass ; Electrodes ; }, abstract = {External resistance is important for the anode and cell performance. However, little attentions were paid on the effect of external resistance on the variation of biofilm structure. Here, we used external resistance ranged from 4000 to 500 Ω for anodic acclimation to investigate the correlation between anode performance and biofilm structure. With the reduce of external resistance, the maximum current density of anode increased from 1.0 to 3.4 A/m[2], which was resulted from a comprehensive effect of reduced charge transfer resistance and increased diffusion resistance. Biological analysis showed that with the reduce of external resistance, biomass and extracellular polymeric substances content increased by 109 and 286%, cell viability increased by 22.7%, which contributed to the reduced charge transfer resistance. But the porosity of anodic biofilm decreased by 27.8%, which led to an increased diffusion resistance of H[+]. This work provided a clear correlation between the electrochemical performance and biofilm structure.}, } @article {pmid34688976, year = {2022}, author = {Li, M and Li, N and Qiu, W and Wang, Q and Jia, J and Wang, X and Yu, J and Li, X and Li, F and Wu, D}, title = {Phenylalanine-based poly(ester urea)s composite films with nitric oxide-releasing capability for anti-biofilm and infected wound healing applications.}, journal = {Journal of colloid and interface science}, volume = {607}, number = {Pt 2}, pages = {1849-1863}, doi = {10.1016/j.jcis.2021.10.016}, pmid = {34688976}, issn = {1095-7103}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Esters ; Humans ; *Nitric Oxide ; Phenylalanine ; Urea ; Wound Healing ; }, abstract = {Infected wounds show delayed and incomplete healing processes and even render patients at a high risk of death due to the formed bacterial biofilms in the wound site, which protect bacteria against antimicrobial treatments and immune response. Nitric oxide based therapy is considered a promising strategy for eliminating biofilms and enhancing wound healing, which encounters a significant challenge of controlling the NO release behavior at the wound site. Herein, a kind of phenylalanine based poly(ester urea)s with high thermal stability are synthesized and fabricated to electrospun films as NO loading vehicle for infected wound treatment. The resultant films can continuously and stably release nitric oxide for 360 h with a total concentration of 1.15 μmol L[-1], which presents obvious advantages in killing the bacteria and removing biofilms. The results exhibit the films have no cytotoxicity and may accelerate the wound repair without causing inflammation, hemolysis, or cytotoxic reactions as well as stimulate the proliferation of fibroblasts and increase the synthesis of collagen. Therefore, the films may be a suitable NO releasing dressing for removing biofilms and repairing infected wounds.}, } @article {pmid34688141, year = {2021}, author = {Sun, J and Wang, D and Sun, Z and Liu, F and Du, L and Wang, D}, title = {The combination of ultrasound and chlorogenic acid to inactivate Staphylococcus aureus under planktonic, biofilm, and food systems.}, journal = {Ultrasonics sonochemistry}, volume = {80}, number = {}, pages = {105801}, pmid = {34688141}, issn = {1873-2828}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Chlorogenic Acid/pharmacology ; Microbial Sensitivity Tests ; *Plankton ; *Staphylococcus aureus ; }, abstract = {This study aimed to investigate the mechanism of different treatments, namely, ultrasound (US), chlorogenic acid (CA), and ultrasound combined with chlorogenic acid (US plus CA) on the inactivation of Staphylococcus aureus planktonic and biofilm cells. Results showed that the combined treatment of US and CA exhibited remarkable synergistic antibacterial and antibiofilm effects. Scanning electron microscopy images indicated that the combined treatment of US and CA caused the most serious damage to the cell morphology. Confocal laser scanning microscopy images revealed that the combined treatment led to sharp increase and severe damage to the permeability of the cell membrane, causing the release of ATP and nucleic acids and decreasing the exopolysaccharide contents in S. aureus biofilm. Finally, the combined treatment of US plus 1% CA for 60 min inactivated S. aureus cells by 1.13 lg CFU/g on mutton. Thus, the combined treatment of US and CA had synergistic effect against S. aureus under planktonic, biofilm, and food systems.}, } @article {pmid34687814, year = {2021}, author = {da Silva Filho, PM and Andrade, AL and Lopes, JBAC and Pinheiro, AA and de Vasconcelos, MA and Fonseca, SGDC and Lopes, LGF and Sousa, EHS and Teixeira, EH and Longhinotti, E}, title = {The biofilm inhibition activity of a NO donor nanosilica with enhanced antibiotics action.}, journal = {International journal of pharmaceutics}, volume = {610}, number = {}, pages = {121220}, doi = {10.1016/j.ijpharm.2021.121220}, pmid = {34687814}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Nitric Oxide Donors/pharmacology ; Renal Dialysis ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Nitric oxide (NO) has emerged as a promising antibacterial agent, where NO donor compounds have been explored. Here, we investigated the role of a silica nanoparticle containing nitroprusside (MPSi-NP) as a NO donor agent against methicillin-sensitive (ATCC 25,923 and ATCC 12228) and methicillin-resistant (ATCC 700,698 and ATCC 35984) Staphylococcus strains. Biofilm inhibition was studied along with antibiotic activity in combination with standard antibiotics (ampicillin and tetracycline). MPSi-NP exhibited thermal release of 63% of NO within 24 h, while free nitroprusside released only 18% during a dialysis assay, indicating an assisted release of NO mediated by the nanoparticles. This nanomaterial showed only a moderate activity in blocking biofilm production, but exhibited a significant decrease in the number of viable bacterial cells (over 600-fold for Staphylococcus aureus ATCC 700,698 and Staphylococcus epidermidis ATCC 35984). Remarkably, even using MPSi-NP at concentrations below any antibacterial action, its combination with ampicillin promoted a significant decrease in MIC for resistant strains of S. aureus ATCC 700,698 (2-fold) and S. epidermidis ATCC 35,984 (4-fold). A carbopol-based gel formulation with MPSi-NP (0.5% w/w) was prepared and showed a zone of inhibition of 7.7 ± 0.6 mm for S. epidermidis ATCC 35984. Topical use of MPSi-NP in combination with antibiotics might be a manageable strategy to prevent and eventually treat complicated resistant bacterial infections.}, } @article {pmid34687564, year = {2022}, author = {Haines, RR and Putsathit, P and Tai, AS and Hammer, KA}, title = {Antimicrobial effects of Melaleuca alternifolia (tea tree) essential oil against biofilm-forming multidrug-resistant cystic fibrosis-associated Pseudomonas aeruginosa as a single agent and in combination with commonly nebulized antibiotics.}, journal = {Letters in applied microbiology}, volume = {75}, number = {3}, pages = {578-587}, doi = {10.1111/lam.13589}, pmid = {34687564}, issn = {1472-765X}, support = {Conquer Cystic Fibrosis Research Grant//Conquer Cystic Fibrosis/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Aztreonam/pharmacology ; Biofilms ; Colistin/pharmacology ; *Cystic Fibrosis ; *Melaleuca ; Microbial Sensitivity Tests ; *Oils, Volatile/pharmacology ; Pseudomonas aeruginosa ; Tea ; *Tea Tree Oil/pharmacology ; Tobramycin/pharmacology ; Trees ; }, abstract = {Broth microdilution assays were used to determine minimum inhibitory concentrations (MICs) and fractional inhibitory concentration indices (FICIs) of tea tree oil (TTO), tobramycin, colistin and aztreonam (ATM) against clinical cystic fibrosis-associated Pseudomonas aeruginosa (CFPA) isolates (n = 20). The minimum biofilm eradication concentration (MBEC) and fractional biofilm eradication concentration index (FBECI) were also determined using a similar microbroth dilution checkerboard assay, with biofilms formed using the MBEC device[®] . TTO was effective at lower concentrations against multidrug-resistant (MDR) CFPA isolates (n = 3) in a biofilm compared to in a planktonic state (MBEC 18·7-fold lower than MIC). CFPA within biofilm was less susceptible to ATM, colistin and tobramycin compared to planktonic cells (MBEC 6·3-fold, 9·3-fold, and 2·1-fold higher than MIC respectively). All combinations of essential oil and antibiotic showed indifferent relationships (FICI 0·52-1·72) when tested against planktonic MDR CFPA isolates (n = 5). Against CFPA isolates (n = 3) in biofilm, combinations of TTO/aztreonam and TTO/colistin showed indifferent relationships (mean FBECI 0·85 and 0·60 respectively), whereas TTO/tobramycin showed a synergistic relationship (mean FBECI 0·42). The antibiofilm properties of TTO and the synergistic relationship seen between TTO and tobramycin against CFPA in vitro make inhaled TTO a promising candidate as a potential therapeutic agent.}, } @article {pmid34685006, year = {2021}, author = {Spirescu, VA and Șuhan, R and Niculescu, AG and Grumezescu, V and Negut, I and Holban, AM and Oprea, OC and Bîrcă, AC and Vasile, BȘ and Grumezescu, AM and Bejenaru, LE and Mogoşanu, GD and Bejenaru, C and Balaure, PC and Andronescu, E and Mogoantă, L}, title = {Biofilm-Resistant Nanocoatings Based on ZnO Nanoparticles and Linalool.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {34685006}, issn = {2079-4991}, abstract = {Biofilms represent an increasing challenge in the medical practice worldwide, imposing a serious threat to public health. As bacterial strains have developed antibiotic resistance, researcher's attention has been extensively focused on developing more efficient antimicrobial strategies. In this context, the present study reports the synthesis, physicochemical characterization, ex vivo biodistribution, and in vitro evaluation of the capacity of nanostructured surfaces based on zinc oxide (ZnO) and biologically active molecules to modulate clinically relevant microbial biofilms. ZnO nanoparticles (NPs) were synthesized through a co-precipitation method without thermal treatment. The matrix-assisted pulsed laser evaporation (MAPLE) was applied for preparing nanostructured coatings based on ZnO NPs surface modified with linalool that were further characterized by X-ray diffraction (XRD), thermogravimetric analysis with differential scanning calorimetry (TGA-DSC), scanning electron microscopy (SEM), transmission electron microscopy with selected area electron diffraction (TEM-SAED), Fourier-transform infrared spectroscopy (FT-IR), and infrared microscopy (IRM). Histological analyses carried out at 7 days and 14 days after the intraperitoneal administration of linalool modified ZnO NPs revealed the absence of the latter from the brain, kidney, liver, lung, myocardium, and pancreas. Through in vitro assays on prokaryotic cells, it was proven that ZnO coatings hinder microbial biofilm formation of both Gram-positive and Gram-negative bacteria strains.}, } @article {pmid34684294, year = {2021}, author = {Ochońska, D and Ścibik, Ł and Brzychczy-Włoch, M}, title = {Biofilm Formation of Clinical Klebsiella pneumoniae Strains Isolated from Tracheostomy Tubes and Their Association with Antimicrobial Resistance, Virulence and Genetic Diversity.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34684294}, issn = {2076-0817}, support = {N41/DBS/000456//Jagiellonian University Medical College/ ; }, abstract = {(1) Background: Due to the commonness of tracheotomy procedures and the wide use of biomaterials in the form of tracheostomy tubes (TTs), the problem of biomaterial-associated infections (BAIs) is growing. Bacterial colonization of TTs results in the development of biofilms on the surface of biomaterials, which may contribute to the development of invasive infections in tracheostomized patients. (2) Methods: Clinical strains of K. pneumoniae, isolated from TTs, were characterized according to their ability to form biofilms, as well as their resistance to antibiotics, whether they harbored ESβL genes, the presence of selected virulence factors and genetic diversity. (3) Results: From 53 patients, K. pneumoniae were detected in 18 of the TTs examined, which constituted 34% of all analyzed biomaterials. Three of the strains (11%) were ESβL producers and all had genes encoding CTX-M-1, SHV and TEM enzymes. 44.4% of isolates were biofilm formers, SEM demonstrating that K. pneumoniae formed differential biofilms on the surface of polyethylene (PE) and polyvinyl chloride (PVC) TTs in vitro. A large range of variation in the share of fimbrial genes was observed. PFGE revealed sixteen genetically distinct profiles. (4) Conclusions: Proven susceptibility of TT biomaterials to colonization by K. pneumoniae means that the attention of research groups should be focused on achieving a better understanding of the bacterial pathogens that form biofilms on the surfaces of TTs. In addition, research efforts should be directed at the development of new biomaterials or the modification of existing materials, in order to prevent bacterial adhesion to their surfaces.}, } @article {pmid34683490, year = {2021}, author = {Yu, EM and Li, ZC and Li, ZF and Wang, GJ and Xia, Y and Zhang, K and Tian, JJ and Gong, WB and Xie, J}, title = {New Insights into the Relationships between Bacterial Dynamics and Water Quality of Aquaculture Systems Supplemented with Carbon Source and Biofilm Substratum.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683490}, issn = {2076-2607}, support = {2019YFD09003//National Key R&D Program of China/ ; CARS-45-21//Modern Agro-industry Technology Research System/ ; 201804010163//Guangzhou Science and Technology Program/ ; }, abstract = {Aquaculture is crucial for achieving the FAO's goal of a world without hunger and malnutrition. Recently, biofilm substratum has been proposed as an effective means to control waste pollution caused by excessive nutrient inputs from aquaculture, but key bacterial communities involved in the remediation remain unclear. Here we reported a freshwater mesocosm study where the addition of biofilm substrata with external carbon effectively controlled the total ammonia nitrogen and improved fish growth. 16S rRNA study and Weighted UniFrac analysis revealed that bacterial compositions were significantly different (999 permutations, p-value < 0.01) between the biofilm-substrata-added and biofilm-substrata-free systems. Planctomycetes were found, as key bacteria benefited from the biofilm substrata addition and exerted the major function of ammonia nitrogen control. Our study demonstrated that the addition of biofilm substrata and an external carbon source favored fish growth and improved the aquaculture environment by the formation of a unique bacteria community.}, } @article {pmid34683474, year = {2021}, author = {Fais, LMG and de Sales Leite, L and Reis, BAD and Ribeiro, ALR and Vaz, LG and Klein, MI}, title = {Microbial Adhesion and Biofilm Formation on Bioactive Surfaces of Ti-35Nb-7Zr-5Ta Alloy Created by Anodization.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683474}, issn = {2076-2607}, support = {2016/08021-5 and 2017/08192-7//São Paulo Research Foundation/ ; PNPD//Coordenação de Aperfeicoamento de Pessoal de Nível Superior/ ; }, abstract = {This study evaluated the microbial colonization (adhesion and biofilm) on modified surfaces of a titanium alloy, Ti-35Nb-7Zr-5Ta, anodized with Ca and P or F ions, with and without silver deposition. The chemical composition, surface topography, roughness (Ra), and surface free energy were evaluated before and after the surface modifications (anodizing). Adhesion and biofilm formation on saliva-coated discs by primary colonizing species (Streptococcus sanguinis, Streptococcus gordonii, Actinomyces naeslundii) and a periodontal pathogen (Porphyromonasgingivalis) were assessed. The surfaces of titanium alloys were modified after anodizing with volcano-shaped micropores with Ca and P or nanosized with F, both with further silver deposition. There was an increase in the Ra values after micropores formation; CaP surfaces became more hydrophilic than other surfaces, showing the highest polar component. For adhesion, no difference was detected for S. gordonii on all surfaces, and some differences were observed for the other three species. No differences were found for biofilm formation per species on all surfaces. However, S. gordonii biofilm counts on distinct surfaces were lower than S. sanguinis, A. naeslundii, and P. gingivalis on some surfaces. Therefore, anodized Ti-35Nb-7Zr-5Ta affected microbial adhesion and subsequent biofilm, but silver deposition did not hinder the colonization of these microorganisms.}, } @article {pmid34683419, year = {2021}, author = {Norouzi, M and Saberi, R and Niyyati, M and Lorenzo-Morales, J and Mirjalali, H and Fatemi, M and Javanmard, E and Karamati, SA}, title = {Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683419}, issn = {2076-2607}, support = {PI18/01380//Instituto de Salud Carlos III, Spain and RICET [RD16/0027/0001 project, from Programa Redes Temáticas de Investigación Cooperativa, FIS (Ministerio Español de Salud, Madrid, Spain), FEDER./ ; 23422//Infectious Diseases and Tropical Medicine Research Center/ ; }, abstract = {Free-living amoeba (FLA) are ubiquitously distributed in the environment. However, they are also the causative agents of opportunistic infections in humans and other animals. A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. Moreover, FLA have been detected in various biofilms around the world. Therefore, the present study aimed to check for presence of FLA in samples from household biofilms in Iran and to characterize them at the molecular level. A total of 69 biofilm samples collected from showerheads, kitchen areas, and bathroom sinks were analyzed. Positive samples for FLA were characterized at the morphological and molecular levels. Furthermore, the results of morphology analysis indicated that 26.08% (18/69) of biofilm samples were positive for Acanthamoeba spp., Vermamoeba genus, and Vahlkampfiids. According to sequence analysis, five strains of Acanthamoeba isolates related to the T4 genotype and two strains belonged to the T2 genotype. In addition, the pathogenic potential of Acanthamoeba-positive isolates was conducted using the tolerance ability test. The results of BLASTn of Vermamoeba sequences were similar to what was expected for Vermamoeba vermiformis. The above-mentioned reasons revealed that the relative high contamination of household biofilm samples with FLA may pose a risk for people using soft contact lenses and for patients with traumatic cataract. Our finding proposes that filtration should be performed in shower heads and indicates the need to monitor people at increased risk of Acanthamoeba keratitis.}, } @article {pmid34683395, year = {2021}, author = {Li, Y and Wu, MX}, title = {Reversal of Polymicrobial Biofilm Tolerance to Ciprofloxacin by Blue Light plus Carvacrol.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683395}, issn = {2076-2607}, support = {FA9550-17-1-0277 and FA9550-20-1-0063//the Defense/Air Force Office of Scientific Research Military Photomedicine Program/ ; }, abstract = {Chronic wound infections are often caused by multi-species biofilms and these biofilm-embedded bacteria exhibit remarkable tolerance to existing antibiotics, which presents huge challenges to control such infections in the wounds. In this investigation, we established a polymicrobial biofilm composed of P. aeruginosa, S. aureus, K. pneumoniae, and A. baumannii. We tested a cocktail therapy comprising 405-nm blue light (BL), carvacrol (Ca), and antibiotics on the multispecies biofilm. Despite the fact that all strains used to form the biofilm were susceptible to ciprofloxacin (CIP) in planktonic cultures, the biofilm was found to withstand ciprofloxacin as well as BL-Ca dual treatment, mainly because K. pneumoniae outgrew and became dominant in the biofilm after each treatment. Strikingly, when ciprofloxacin was combined with BL-Ca, the multispecies biofilms succumbed substantially and were eradicated at an efficacy of 99.9%. Mechanistically, BL-Ca treatment increased membrane permeability and potentiated the anti-biofilm activity of ciprofloxacin, probably by facilitating ciprofloxacin's entrance of the bacteria, which is particularly significant for K. pneumoniae, a species that is refractory to either ciprofloxacin or BL-Ca dual treatment. The results suggest that bacterial membrane damage can be one of the pivotal strategies to subvert biofilm tolerance and combat the recalcitrant multispecies biofilms.}, } @article {pmid34683366, year = {2021}, author = {Pineda, MR and Byrd, JA and Genovese, KJ and Farnell, YZ and Zhao, D and Wang, X and Milby, AC and Farnell, MB}, title = {Evaluation of Sodium Bisulfate on Reducing Salmonella Heidelberg Biofilm and Colonization in Broiler Crops and Ceca.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683366}, issn = {2076-2607}, support = {not applicable//Jones-Hamilton Company/ ; }, abstract = {Salmonella Heidelberg (SH) on contaminated poultry causes economic and health risks to producers and consumers. We hypothesized that sodium bisulfate (SBS) would decrease SH biofilm on polyvinyl chloride (PVC) coupons and decrease the horizontal transfer of SH in broilers. Experiment 1: Salmonella Heidelberg biofilm was cultured with PVC coupons, which were treated with SBS at a pH of 3.5 for 10 min, 8 h, and 24 h. Experiment 2: Nine replicate pens per treatment were divided between two rooms. A seeder contact model was used to mimic a natural infection environment. Treatments consisted of tap water or sodium bisulfate in water at a pH of 3.5. Salmonella Heidelberg incidence and enumeration were measured in crops and ceca. Sodium bisulfate significantly reduced biofilm by 2.16 and 1.04 logs when treated for 8 and 24 h, respectively. Crop colonization was significantly decreased in trials 1 and 2 by 0.29 and 0.23 logs, respectively. Crop pH was significantly decreased in trial 2. Ceca colonization was significantly decreased in trial 1 by 0.39 logs. The results from the present study suggest that SBS may be administered to drinking water to decrease SH gut colonization and to reduce biofilm.}, } @article {pmid34683356, year = {2021}, author = {Varin-Simon, J and Lamret, F and Colin, M and Gangloff, SC and Mongaret, C and Reffuveille, F}, title = {Comparison of Two Cutibacterium acnes Biofilm Models.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683356}, issn = {2076-2607}, abstract = {The study of biofilms in vitro is complex and often limited by technical problems due to simplified models. Here, we compared C. acnes biofilm formation, from species involved in bone and prosthesis infection, in a static model with a dynamic model. Using similar parameters, the percentage of live bacteria within the biofilm was higher in dynamic than in static approach. In both models, bacterial internalization in osteoblast-like cells, playing the role of stress factor, affected this proportion but in opposite ways: increase of live bacteria proportion in the static model (×2.04 ± 0.53) and of dead bacteria proportion (×3.5 ± 1.03) in the dynamic model. This work highlights the huge importance in the selection of a relevant biofilm model in accordance with the environmental or clinical context to effectively improve the understanding of biofilms and the development of better antibiofilm strategies.}, } @article {pmid34683353, year = {2021}, author = {Aqawi, M and Sionov, RV and Gallily, R and Friedman, M and Steinberg, D}, title = {Anti-Biofilm Activity of Cannabigerol against Streptococcus mutans.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683353}, issn = {2076-2607}, support = {0000//STEP-GTP sisters fellowship (2019-2021)/ ; }, abstract = {Streptococcus mutans is a common cariogenic bacterium in the oral cavity involved in plaque formation. Previous studies showed that Cannabigerol (CBG) has bacteriostatic and bacteriocidic activity against S. mutans. The aim of the present study was to study its effect on S. mutans biofilm formation and dispersion. S. mutans was cultivated in the presence of CBG, and the resulting biofilms were examined by CV staining, MTT assay, qPCR, biofilm tracer, optical profilometry, and SEM. Gene expression was determined by real-time qPCR, extracellular polysaccharide (EPS) production was determined by Congo Red, and reactive oxygen species (ROS) were determined using DCFH-DA. CBG prevented the biofilm formation of S. mutans shown by reduced biofilm biomass, decreased biofilm thickness, less EPS production, reduced DNA content, diminished metabolic activity, and increased ROS levels. CBG altered the biofilm roughness profile, resulting in a smoother biofilm surface. When treating preformed biofilms, CBG reduced the metabolic activity of S. mutans with a transient effect on the biomass. CBG reduced the expression of various genes involved in essential metabolic pathways related to the cariogenic properties of S. mutans biofilms. Our data show that CBG has anti-biofilm activities against S. mutans and might be a potential drug for preventive treatment of dental caries.}, } @article {pmid34683338, year = {2021}, author = {Šilha, D and Sirotková, S and Švarcová, K and Hofmeisterová, L and Koryčanová, K and Šilhová, L}, title = {Biofilm Formation Ability of Arcobacter-like and Campylobacter Strains under Different Conditions and on Food Processing Materials.}, journal = {Microorganisms}, volume = {9}, number = {10}, pages = {}, pmid = {34683338}, issn = {2076-2607}, abstract = {Campylobacter&nbsp;jejuni is the most frequent cause of bacterial gastrointestinal food-borne infection worldwide. The transmission of Campylobacter and Arcobacter-like species is often made possible by their ability to adhere to various abiotic surfaces. This study is focused on monitoring the biofilm ability of 69 strains of Campylobacter spp. and lesser described species of the Arcobacteraceae family isolated from food, water, and clinical samples within the Czech Republic. Biofilm formation was monitored and evaluated under an aerobic/microaerophilic atmosphere after cultivation for 24 or 72 h depending on the surface material. An overall higher adhesion ability was observed in arcobacters. A chi-squared test showed no association between the origin of the strains and biofilm activity (p > 0.05). Arcobacter-like species are able to form biofilms under microaerophilic and aerobic conditions; however, they prefer microaerophilic environments. Biofilm formation has already been demonstrated at refrigerator temperatures (5 °C). Arcobacters also showed higher biofilm formation ability at the temperature of 30 °C. This is in contrast to Campylobacter&nbsp;jejuni NP 2896, which showed higher biofilm formation ability at temperatures of 5-30 °C. Overall, the results demonstrated the biofilm formation ability of many strains, which poses a considerable risk to the food industry, medical practice, and human health.}, } @article {pmid34681114, year = {2021}, author = {Lianou, DT and Petinaki, E and Cripps, PJ and Gougoulis, DA and Michael, CK and Tsilipounidaki, K and Skoulakis, A and Katsafadou, AI and Vasileiou, NGC and Giannoulis, T and Voidarou, C and Mavrogianni, VS and Caroprese, M and Fthenakis, GC}, title = {Antibiotic Resistance of Staphylococci from Bulk-Tank Milk of Sheep Flocks: Prevalence, Patterns, Association with Biofilm Formation, Effects on Milk Quality, and Risk Factors.}, journal = {Biology}, volume = {10}, number = {10}, pages = {}, pmid = {34681114}, issn = {2079-7737}, abstract = {The objectives of this work were to study prevalence and characteristics of resistance to antibiotics of staphylococcal isolates from the bulk-tank milk of sheep flocks across Greece, to assess possible associations of the presence of antibiotic resistance with the quality of milk in these flocks and to evaluate flock-related factors potentially associated with antibiotic resistance among these isolates. A cross-sectional study was performed in 325 sheep flocks in Greece. Bulk-tank milk samples were collected for bacteriological examination; staphylococcal isolates were evaluated for resistance to 20 antibiotics. Oxacillin-resistant staphylococcal isolates, isolates resistant to any antibiotic, and multi-resistant isolates were recovered from 8.0%, 30.5%, and 12.0% of flocks, respectively. Of 232 isolates, 11.6% were resistant to oxacillin, 46.1% were resistant to at least one antibiotic, and 16.4% were multi-resistant. Resistance was seen more frequently among coagulase-negative (50.6%) than among Staphylococcus aureus (31.5%) isolates. Resistance was more frequent against penicillin and ampicillin (34.1% of isolates), clindamycin (17.7%), and fosfomycin (14.2%). An association was found between biofilm formation by staphylococci and resistance to fosfomycin. For recovery of oxacillin-resistant isolates, the lack of experience by farmers emerged as a significant factor; respective factors for the isolation of staphylococci resistant to any antibiotic or multi-resistant isolates were the early stage of the lactation period (0th-1st month) and the intensive management system applied in the flocks, respectively.}, } @article {pmid34680849, year = {2021}, author = {Spirescu, VA and Niculescu, AG and Slave, Ș and Bîrcă, AC and Dorcioman, G and Grumezescu, V and Holban, AM and Oprea, OC and Vasile, BȘ and Grumezescu, AM and Nica, IC and Stan, MS and Andronescu, E}, title = {Anti-Biofilm Coatings Based on Chitosan and Lysozyme Functionalized Magnetite Nanoparticles.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680849}, issn = {2079-6382}, abstract = {Biofilms represent a common and increasingly challenging problem in healthcare practices worldwide, producing persistent and difficult to manage infections. Researchers have started developing antibiotic-free treatment alternatives in order to decrease the risk of resistant microbial strain selection and for the efficient management of antibiotic tolerant biofilm infections. The present study reports the fabrication and characterization of magnetite-based nanostructured coatings for producing biofilm-resistant surfaces. Specifically, magnetite nanoparticles (Fe3O4) were functionalized with chitosan (CS) and were blended with lysozyme (LyZ) and were deposited using the matrix-assisted pulsed laser evaporation (MAPLE) technique. A variety of characterization techniques were employed to investigate the physicochemical properties of both nanoparticles and nanocoatings. The biological characterization of the coatings assessed through cell viability and antimicrobial tests showed biocompatibility on osteoblasts as well as antiadhesive and antibiofilm activity against both Gram-negative and Gram-positive bacterial strains and no cytotoxic effect against human-cultured diploid cells.}, } @article {pmid34680832, year = {2021}, author = {Englerová, K and Bedlovičová, Z and Nemcová, R and Király, J and Maďar, M and Hajdučková, V and Styková, E and Mucha, R and Reiffová, K}, title = {Bacillus amyloliquefaciens-Derived Lipopeptide Biosurfactants Inhibit Biofilm Formation and Expression of Biofilm-Related Genes of Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680832}, issn = {2079-6382}, support = {APVV-15-0377 and APVV-16-0203//Slovak Research and Development Agency/ ; VEGA 1/0788/19//the Scientific Grant Agency of Ministry of Education of the Slovak Republic/ ; }, abstract = {Biosurfactants (BSs) are surface-active compounds produced by diverse microorganisms, including the genus Bacillus. These bioactive compounds possess biological activities such as antiadhesive, antimicrobial and antibiofilm effects that can lead to important applications in combating many infections. Based on these findings, we decided to investigate the antibiofilm activity of BSs from the marine Bacillus amyloliquefaciens against Staphylococcus aureus CCM 4223. Expression of biofilm-related genes was also evaluated using qRT-PCR. Isolated and partially purified BSs were identified and characterized by molecular tools and by UHPLC-DAD and MALDI-TOF/MS. Bacillus amyloliquefaciens 3/22, that exhibited surfactant activity evaluated by oil spreading assay, was characterized using the 16S rRNA sequencing method. Screening by PCR detected the presence of the sfp, srfAA, fenD and ituD genes, suggesting production of the lipopeptides (LPs) surfactin, fengycin and iturin. The above findings were further supported by the results of UHPLC-DAD and MALDI-TOF/MS. As quantified by the crystal violet method, the LPs significantly (p < 0.001) reduced biofilm formation of S. aureus in a dose-dependent manner and decreased expression of biofilm-related genes fnbA, fnbB, sortaseA and icaADBC operon. Data from our investigation indicate a promising therapeutic application for LPs isolated from B. amyloliquefaciens toward prevention of S. aureus biofilm infections.}, } @article {pmid34680806, year = {2021}, author = {Lianou, DT and Petinaki, E and Cripps, PJ and Gougoulis, DA and Michael, CK and Tsilipounidaki, K and Skoulakis, A and Katsafadou, AI and Vasileiou, NGC and Giannoulis, T and Katsarou, EI and Voidarou, C and Mavrogianni, VS and Caroprese, M and Fthenakis, GC}, title = {Prevalence, Patterns, Association with Biofilm Formation, Effects on Milk Quality and Risk Factors for Antibiotic Resistance of Staphylococci from Bulk-Tank Milk of Goat Herds.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680806}, issn = {2079-6382}, abstract = {The objectives of this work were to study the prevalence and the patterns of antibiotic resistance of staphylococcal isolates from bulk-tank milk of goat herds across Greece, to assess possible associations of the presence of antibiotic resistance with the quality of milk in these herds and to evaluate herd-related factors potentially associated with the presence of antibiotic resistance among these staphylococcal isolates. A cross-sectional study was performed on 119 goat herds in Greece. Bulk-tank milk samples were collected for bacteriological examination; staphylococcal isolates were evaluated for resistance to 20 antibiotics. Oxacillin-resistant, resistant to at least one antibiotic, and multi-resistant staphylococcal isolates were recovered from 5.0%, 30.3%, and 16.0% of herds, respectively. Of 80 isolates, 7.5% were resistant to oxacillin, 50.0% were resistant to at least one antibiotic and 27.5% were multi-resistant. Resistance was seen more frequently among coagulase-negative staphylococci (59.3%) than among Staphylococcus aureus (23.8%). Resistance was more frequent against penicillin and ampicillin (41.3% of isolates) and fosfomycin (27.5%). No association was found with biofilm formation by staphylococci. For recovery of oxacillin-resistant isolates, the presence of working staff in the herds emerged as a significant factor; respective factors for the isolation of staphylococci resistant to at least one antibiotic were part-time farming and high (>10) number of systemic disinfections in the farm annually. The same three factors concurrently were also identified to be significant for the recovery of multi-resistant isolates.}, } @article {pmid34680801, year = {2021}, author = {Mergoni, G and Manfredi, M and Bertani, P and Ciociola, T and Conti, S and Giovati, L}, title = {Activity of Two Antimicrobial Peptides against Enterococcus faecalis in a Model of Biofilm-Mediated Endodontic Infection.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680801}, issn = {2079-6382}, abstract = {Enterococcus faecalis is a common cause of biofilm-associated opportunistic infections, which are often difficult to treat. The formation of E. faecalis biofilms on the dentinal walls of the root canal is frequently the cause of endodontic treatment failure and secondary apical periodontitis. In a preliminary work, two recognized antifungal peptides, KP and L18R, showed antibacterial activity against planktonic E. faecalis cells at micromolar concentrations. Moreover, L18R proved to reduce the biomass in the early stage of E. faecalis biofilm development on polystyrene plates, while a qualitative biofilm inhibition was demonstrated on hydroxyapatite disks by confocal laser scanning microscopy (CLSM). The aim of this study was to better characterize the effect of both peptides on E. faecalis biofilm. A reduction in metabolic activity after peptide treatment was detected by Alamar Blue assay, while a remarkable impairment in the architecture of E. faecalis biofilms on hydroxyapatite disks, along with a significant reduction in viable bacteria, was caused mostly by L18R, as assessed by CLSM and scanning electron microscopy. The lack of cytotoxicity of the investigated peptides against L929 murine fibroblasts was also determined. Obtained results suggest L18R as a promising candidate for the development of new strategies for endodontic infection control.}, } @article {pmid34680772, year = {2021}, author = {Guillín, Y and Cáceres, M and Torres, R and Stashenko, E and Ortiz, C}, title = {Effect of Essential Oils on the Inhibition of Biofilm and Quorum Sensing in Salmonella enteritidis 13076 and Salmonella typhimurium 14028.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680772}, issn = {2079-6382}, support = {1102-777-57586//Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS)/ ; 270//Universidad Industrial de Santander/ ; }, abstract = {The emergence of multidrug-resistant microorganisms represents a global challenge that has led to a search for new antimicrobial compounds. Essential oils (EOs) from medicinal aromatic plants are a potential alternative for conventional antibiotics. In this study, the antimicrobial and anti-biofilm potential of 15 EOs was evaluated on planktonic and biofilm-associated cells of Salmonella enterica serovar Enteritidis ATCC 13076 (S. enteritidis) and Salmonella enterica serovar Typhimurium ATCC 14028 (S. typhimurium). In total, 4 out of 15 EOs showed antimicrobial activity and 6 EOs showed anti-biofilm activity against both strains. The EO from the Lippia origanoides chemotype thymol-carvacrol II (LTC II) presented the lowest minimum inhibitory concentration (MIC50 = 0.37 mg mL[-1]) and minimum bactericidal concentration (MBC = 0.75 mg mL[-1]) values. This EO also presented the highest percentage of biofilm inhibition (>65%) on both microorganisms, which could be confirmed by scanning electron microscopy (SEM) images. Transcriptional analysis showed significant changes in the expression of the genes related to quorum sensing and the formation of the biofilm. EOs could inhibit the expression of genes involved in the quorum sensing mechanism (luxR, luxS, qseB, sdiA) and biofilm formation (csgA, csgB,&nbsp;csgD, flhD, fliZ, and motB), indicating their potential use as anti-biofilm antimicrobial agents. However, further studies are needed to elucidate the action mechanisms of essential oils on the bacterial cells under study.}, } @article {pmid34680738, year = {2021}, author = {Benameur, Q and Gervasi, T and Giarratana, F and Vitale, M and Anzà, D and La Camera, E and Nostro, A and Cicero, N and Marino, A}, title = {Virulence, Antimicrobial Resistance and Biofilm Production of Escherichia coli Isolates from Healthy Broiler Chickens in Western Algeria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {10}, pages = {}, pmid = {34680738}, issn = {2079-6382}, abstract = {The aim of this study was to assess the virulence, antimicrobial resistance and biofilm production of Escherichia coli strains isolated from healthy broiler chickens in Western Algeria. E. coli strains (n = 18) were identified by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. Susceptibility to 10 antibiotics was determined by standard methods. Virulence and extended-spectrum β-lactamase (ESBL) genes were detected by PCR. The biofilm production was evaluated by microplate assay. All the isolates were negative for the major virulence/toxin genes tested (rfbE, fliC, eaeA, stx1), except one was stx2-positive. However, all were resistant to at least three antibiotics. Ten strains were ESBL-positive. Seven carried the β-lactamase blaTEM gene only and two co-harbored blaTEM and blaCTX-M-1 genes. One carried the blaSHV gene. Among the seven strains harboring blaTEM only, six had putative enteroaggregative genes. Two contained irp2, two contained both irp2 and astA, one contained astA and another contained aggR, astA and irp2 genes. All isolates carrying ESBL genes were non-biofilm producers, except one weak producer. The ESBL-negative isolates were moderate biofilm producers and, among them, two harbored astA, two irp2, and one aggR, astA and irp2 genes. This study highlights the spread of antimicrobial-resistant E. coli strains from healthy broiler chickens in Western Algeria.}, } @article {pmid34679846, year = {2021}, author = {Jørgensen, E and Bjarnsholt, T and Jacobsen, S}, title = {Biofilm and Equine Limb Wounds.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {10}, pages = {}, pmid = {34679846}, issn = {2076-2615}, abstract = {In chronic wounds in humans, biofilm formation and wound chronicity are linked, as biofilms contribute to chronic inflammation and delayed healing. Biofilms are aggregates of bacteria, and living as biofilms is the default mode of bacterial life; within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. In horses, delayed healing is more commonly seen in limb wounds than body wounds. Chronic inflammation and hypoxia are the main characteristics of delayed wound healing in equine limbs, and biofilms might also contribute to this healing pattern in horses. However, biofilm formation in equine wounds has been studied to a very limited degree. Biofilms have been detected in equine traumatic wounds, and recent experimental models have shown that biofilms protract the healing of equine limb wounds. Detection of biofilms within wounds necessitates advanced techniques that are not available in routine diagnostic yet. However, infections with biofilm should be suspected in equine limb wounds not healing as expected, as they are in human wounds. Treatment should be based on repeated debridement and application of topical antimicrobial therapy.}, } @article {pmid34679444, year = {2021}, author = {Pouget, C and Dunyach-Remy, C and Pantel, A and Schuldiner, S and Sotto, A and Lavigne, JP}, title = {New Adapted In Vitro Technology to Evaluate Biofilm Formation and Antibiotic Activity Using Live Imaging under Flow Conditions.}, journal = {Diagnostics (Basel, Switzerland)}, volume = {11}, number = {10}, pages = {}, pmid = {34679444}, issn = {2075-4418}, support = {Thématique Phare//CHU Nîmes/ ; PhD Grant Cifre//Biofilm Pharma/ ; }, abstract = {The polymicrobial nature of biofilms and bacterial interactions inside chronic wounds are keys for the understanding of bacterial cooperation. The aim of this present study was to develop a technique to study and visualize biofilm in live imaging under flow conditions (Bioflux™ 200, Fluxion Biosciences). The Bioflux[TM] system was adapted using an in vitro chronic wound-like medium (CWM) that mimics the environment encountered in ulcers. Two reference strains of Staphylococcus aureus (Newman) and Pseudomonas aeruginosa (PAO1) were injected in the Bioflux[TM] during 24 h to 72 h in mono and coculture (ratio 1:1, bacteria added simultaneously) in the CWM vs. a control medium (BHI). The quantification of biofilm formation at each time was evaluated by inverted microscopy. After 72 h, different antibiotics (ceftazidime, imipenem, linezolid, oxacillin and vancomycin) at 1x MIC, 10x MIC and 100x MIC were administrated to the system after an automatic increase of the flow that mimicked a debridement of the wound surface. Biofilm studies highlighted that the two species, alone or associated, constituted a faster and thicker biofilm in the CWM compared to the BHI medium. The effect of antibiotics on mature or "debrided" biofilm indicated that some of the most clinically used antibiotic such as vancomycin or imipenem were not able to disrupt and reduce the biofilm biomass. The use of a life cell imaging with an in vitro CWM represents a promising tool to study bacterial biofilm and investigate microbial cooperation in a chronic wound context.}, } @article {pmid34679146, year = {2021}, author = {Wu, T and Sun, J and Lei, J and Fan, Q and Tang, X and Zhu, G and Yan, Q and Feng, X and Shi, B}, title = {An efficient treatment of biofilm-induced periodontitis using Pt nanocluster catalysis.}, journal = {Nanoscale}, volume = {13}, number = {42}, pages = {17912-17919}, doi = {10.1039/d1nr05198a}, pmid = {34679146}, issn = {2040-3372}, mesh = {Animals ; Biofilms/drug effects ; Catalysis ; Escherichia coli ; Metal Nanoparticles/*therapeutic use ; *Periodontitis/drug therapy ; Platinum/*therapeutic use ; Rats ; Staphylococcus aureus ; }, abstract = {Periodontitis is a common chronic inflammatory disease associated with biofilm formation, gingival recession, and supporting bone loss that can lead to the formation of periodontal pockets and, ultimately, tooth loss. Clinical treatment for periodontitis through scaling and antibiotics still faces the problems of unavoidable bleeding, injury to periodontal tissue, drug resistance, and insufficient treatment. Herein we prepared an injectable anti-periodontitis ointment with catalytic activity that consists of Pt nanocluster (PtNC) modified g-C3N4 (CN), and PEG400/PEG4000, which efficiently treated biofilm-infected periodontitis. PtNCs (<2 nm) with ultralow content (0.07%) were formed on the surface of CN using mild ultraviolet (UV) irradiation. Due to the strong O2 adsorption and activation ability of CN-PtNCs and their mutual electron transfer, they show both oxidase-like and peroxidase-like activities and produce reactive oxygen species (ROS) in the dark. CN-PtNCs showed strong biofilm elimination ability towards Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, benefiting from the good biocompatibility of CN-PtNCs and the injectable property of the PEG400/PEG4000 ointment, the CN-PtNC ointment with high bioavailability successfully treated periodontitis in rats, alleviating inflammation and reducing bone loss, and showed better performance than periocline. Therefore, this catalytic system is promising for an efficient, non-invasive, and antibiotic-free treatment of periodontitis.}, } @article {pmid34679069, year = {2021}, author = {Kita, M and Kanai, K and Ono, HK and Otaka, Y and Okada, D and Nagai, N and Kudo, R and Yamashita, Y and Hino, S and Matsunaga, T and Tajima, K}, title = {Retention, Bacterial Adhesion, and Biofilm Formation between Anionic and Zwitterionic Bandage Contact Lenses in Healthy Dogs: A Pilot Study.}, journal = {Veterinary sciences}, volume = {8}, number = {10}, pages = {}, pmid = {34679069}, issn = {2306-7381}, support = {2019- 201-0038//SEED Co., Ltd. Grant/ ; }, abstract = {This study aimed to compare the in vitro and in vivo retention, bacterial adhesion, and biofilm formation between anionic and zwitterionic bandage contact lenses (BCLs) in healthy canines. BCL retention and tolerance were evaluated in 10 healthy canines via a single-masked, crossover study for 7 days. To compare in vitro bacterial adhesion and biofilm formation, four Staphylococcus strains were incubated with the BCLs at 37 °C for 2 or 24 h, and the bacterial colony forming units (CFUs) adhering to the BCLs were counted. Next, to compare in vivo bacterial adhesion, the CFUs of bacteria adhering to the BCLs worn by canines for 24 h were counted. Anionic lenses significantly retained and reduced in vitro bacterial adhesion than in the zwitterionic lenses. However, the amount of in vitro biofilm formation was more likely to be higher on anionic lenses than on zwitterionic lenses. In vivo bacterial adhesion was not significantly different between the two types of BCLs. Nevertheless, both BCLs were well-tolerated by the canines; thus, their short-term use in dogs can be recommended as safe.}, } @article {pmid34678363, year = {2022}, author = {Tamminen, M and Spaak, J and Tlili, A and Eggen, R and Stamm, C and Räsänen, K}, title = {Wastewater constituents impact biofilm microbial community in receiving streams.}, journal = {The Science of the total environment}, volume = {807}, number = {Pt 3}, pages = {151080}, doi = {10.1016/j.scitotenv.2021.151080}, pmid = {34678363}, issn = {1879-1026}, mesh = {Anthropogenic Effects ; Biofilms ; *Microbiota ; *Wastewater ; }, abstract = {Microbial life in natural biofilms is dominated by prokaryotes and microscopic eukaryotes living in dense association. In stream ecosystems, microbial biofilms influence primary production, elemental cycles, food web interactions as well as water quality. Understanding how biofilm communities respond to anthropogenic impacts, such as wastewater treatment plant (WWTP) effluent, is important given the key role of biofilms in stream ecosystem function. Here, we implemented 16S and 18S rRNA gene sequencing of stream biofilms upstream (US) and downstream (DS) of WWTP effluents in four Swiss streams to test how bacterial and eukaryotic communities respond to wastewater constituents. Stream biofilm composition was strongly affected by geographic location - particularly for bacteria. However, the abundance of certain microbial community members was related to micropollutants in the wastewater - among bacteria, micropollutant-associated members were found e.g. in Alphaproteobacteria, and among eukaryotes e.g. in Bacillariophyta (algal diatoms). This study corroborates several previously characterized responses (e.g. as seen in diatoms), but also reveals previously unknown community responses - such as seen in Alphaproteobacteria. This study advances our understanding of the ecological impact of the current wastewater treatment practices and provides information about potential new marker organisms to assess ecological change in stream biofilms.}, } @article {pmid34678351, year = {2022}, author = {Al-Wrafy, FA and Al-Gheethi, AA and Ponnusamy, SK and Noman, EA and Fattah, SA}, title = {Nanoparticles approach to eradicate bacterial biofilm-related infections: A critical review.}, journal = {Chemosphere}, volume = {288}, number = {Pt 2}, pages = {132603}, doi = {10.1016/j.chemosphere.2021.132603}, pmid = {34678351}, issn = {1879-1298}, mesh = {*Bacterial Infections ; Biofilms ; Drug Carriers ; Humans ; *Nanoparticles ; Nanotechnology ; }, abstract = {Biofilm represents one of the crucial factors for the emergence of multi-drug resistance bacterial infections. The high mortality, morbidity and medical device-related infections are associated with biofilm formation, which requires primarily seek alternative treatment strategies. Recently, nanotechnology has emerged as a promising method for eradicating bacterial biofilm-related infection. The efficacy of nanoparticles (NPs) against bacterial infections interest great attention, and the researches on the subject are rapidly increasing. However, the majority of studies continue to focus on the antimicrobial effects of NPs in vitro, while only a few achieved in vivo and very few registered as clinical trials. The present review aimed to organize the scattered available information regarding NPs approach to eradicate bacterial biofilm-related infections. The current review highlighted the advantages and disadvantages associated with this approach, in addition to the challenges that prevent reaching the clinical applications. It was appeared that the production of NPs either as antimicrobials or as drug carriers requires further investigations to overcome the obstacles associated with their kinetic and biocompatibility.}, } @article {pmid34677317, year = {2021}, author = {Brunetti, G and Conteduca, D and Armenise, MN and Ciminelli, C}, title = {Novel Micro-Nano Optoelectronic Biosensor for Label-Free Real-Time Biofilm Monitoring.}, journal = {Biosensors}, volume = {11}, number = {10}, pages = {}, pmid = {34677317}, issn = {2079-6374}, support = {POR Puglia FESR FSR 2014-2020 - Action 10.4 - "Research for Innovation" (REFIN) Initiative//Regione Puglia/ ; }, mesh = {Anti-Bacterial Agents ; Bacteria ; *Biofilms ; *Biosensing Techniques ; Electricity ; *Environmental Monitoring ; Humans ; Nanostructures ; }, abstract = {According to the World Health Organization forecasts, AntiMicrobial Resistance (AMR) is expected to become one of the leading causes of death worldwide in the following decades. The rising danger of AMR is caused by the overuse of antibiotics, which are becoming ineffective against many pathogens, particularly in the presence of bacterial biofilms. In this context, non-destructive label-free techniques for the real-time study of the biofilm generation and maturation, together with the analysis of the efficiency of antibiotics, are in high demand. Here, we propose the design of a novel optoelectronic device based on a dual array of interdigitated micro- and nanoelectrodes in parallel, aiming at monitoring the bacterial biofilm evolution by using optical and electrical measurements. The optical response given by the nanostructure, based on the Guided Mode Resonance effect with a Q-factor of about 400 and normalized resonance amplitude of about 0.8, allows high spatial resolution for the analysis of the interaction between planktonic bacteria distributed in small colonies and their role in the biofilm generation, calculating a resonance wavelength shift variation of 0.9 nm in the presence of bacteria on the surface, while the electrical response with both micro- and nanoelectrodes is necessary for the study of the metabolic state of the bacteria to reveal the efficacy of antibiotics for the destruction of the biofilm, measuring a current change of 330 nA when a 15 µm thick biofilm is destroyed with respect to the absence of biofilm.}, } @article {pmid34675902, year = {2021}, author = {Kriem, LS and Wright, K and Ccahuana-Vasquez, RA and Rupp, S}, title = {Mapping of a Subgingival Dual-Species Biofilm Model Using Confocal Raman Microscopy.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {729720}, pmid = {34675902}, issn = {1664-302X}, abstract = {Techniques for continuously monitoring the formation of subgingival biofilm, in relation to the determination of species and their accumulation over time in gingivitis and periodontitis, are limited. In recent years, advancements in the field of optical spectroscopic techniques have provided an alternative for analyzing three-dimensional microbiological structures, replacing the traditional destructive or biofilm staining techniques. In this work, we have demonstrated that the use of confocal Raman spectroscopy coupled with multivariate analysis provides an approach to spatially differentiate bacteria in an in vitro model simulating a subgingival dual-species biofilm. The present study establishes a workflow to evaluate and differentiate bacterial species in a dual-species in vitro biofilm model, using confocal Raman microscopy (CRM). Biofilm models of Actinomyces denticolens and Streptococcus oralis were cultured using the "Zürich in vitro model" and were analyzed using CRM. Cluster analysis was used to spatially differentiate and map the biofilm model over a specified area. To confirm the clustering of species in the cultured biofilm, confocal laser scanning microscopy (CLSM) was coupled with fluorescent in vitro hybridization (FISH). Additionally, dense bacteria interface area (DBIA) samples, as an imitation of the clusters in a biofilm, were used to test the developed multivariate differentiation model. This confirmed model was successfully used to differentiate species in a dual-species biofilm and is comparable to morphology. The results show that the developed workflow was able to identify main clusters of bacteria based on spectral "fingerprint region" information from CRM. Using this workflow, we have demonstrated that CRM can spatially analyze two-species in vitro biofilms, therefore providing an alternative technique to map oral multi-species biofilm models.}, } @article {pmid34672512, year = {2021}, author = {Ziege, R and Tsirigoni, AM and Large, B and Serra, DO and Blank, KG and Hengge, R and Fratzl, P and Bidan, CM}, title = {Adaptation of Escherichia coli Biofilm Growth, Morphology, and Mechanical Properties to Substrate Water Content.}, journal = {ACS biomaterials science & engineering}, volume = {7}, number = {11}, pages = {5315-5325}, pmid = {34672512}, issn = {2373-9878}, mesh = {Bacteria ; Biofilms ; *Escherichia coli ; *Water ; }, abstract = {Biofilms are complex living materials that form as bacteria become embedded in a matrix of self-produced protein and polysaccharide fibers. In addition to their traditional association with chronic infections or clogging of pipelines, biofilms currently gain interest as a potential source of functional material. On nutritive hydrogels, micron-sized Escherichia coli cells can build centimeter-large biofilms. During this process, bacterial proliferation, matrix production, and water uptake introduce mechanical stresses in the biofilm that are released through the formation of macroscopic delaminated buckles in the third dimension. To clarify how substrate water content could be used to tune biofilm material properties, we quantified E. coli biofilm growth, delamination dynamics, and rigidity as a function of water content of the nutritive substrates. Time-lapse microscopy and computational image analysis revealed that softer substrates with high water content promote biofilm spreading kinetics, while stiffer substrates with low water content promote biofilm delamination. The delaminated buckles observed on biofilm cross sections appeared more bent on substrates with high water content, while they tended to be more vertical on substrates with low water content. Both wet and dry biomass, accumulated over 4 days of culture, were larger in biofilms cultured on substrates with high water content, despite extra porosity within the matrix layer. Finally, microindentation analysis revealed that substrates with low water content supported the formation of stiffer biofilms. This study shows that E. coli biofilms respond to substrate water content, which might be used for tuning their material properties in view of further applications.}, } @article {pmid34672225, year = {2022}, author = {Kanekar, S and Fathima, F and Rekha, PD}, title = {Carvone - a quorum sensing inhibitor blocks biofilm formation in Chromobacterium violaceum.}, journal = {Natural product research}, volume = {36}, number = {17}, pages = {4546-4551}, doi = {10.1080/14786419.2021.1993214}, pmid = {34672225}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Chromobacterium ; Cyclohexane Monoterpenes ; Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {Carvone is a natural monoterpenoid and in this study it was tested for its role in attenuating quorum sensing (QS) controlled biofilm formation in Chromobacterium violaceum. It showed significant QS inhibition in terms of reduction in violacein at a concentration range of 60 to 70 µg/mL against C. violaceum ATCC 12472. At the same concentration, carvone also inhibited biofilm formation by more than 80%. The biofilm morphology of C. violaceum is unique with a well organised pattern of cell arrangement in a tight matrix. The same was evident in Scanning electron microscopy, however, carvone treatment not only showed reduction in biofilm density but also disruption of biofilm matrix. Interruption of biofilm formation was attributed to reduction in the exopolysaccharide production and swarming motility. Molecular investigations (RT-PCR) showed that the important genes involved in biofilm regulation such as pilS, pilR, pilB and pilT were downregulated significantly in the treatment groups.}, } @article {pmid34671824, year = {2021}, author = {Takahashi, C and Sato, M and Sato, C}, title = {Biofilm formation of Staphylococcus epidermidis imaged using atmospheric scanning electron microscopy.}, journal = {Analytical and bioanalytical chemistry}, volume = {413}, number = {30}, pages = {7549-7558}, pmid = {34671824}, issn = {1618-2650}, support = {JP15K18849//Japan Society for the Promotion of Science/ ; JP 17KK0178//Japan Society for the Promotion of Science/ ; JP18K18388//Japan Society for the Promotion of Science/ ; }, mesh = {*Biofilms ; Microscopy, Electron, Scanning/*methods ; Nanotubes ; Staining and Labeling ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*metabolism ; }, abstract = {Staphylococcus epidermidis are gram-positive bacteria that form a biofilm around implanted devices and develop an infection into a chronic state. Recently, it has been revealed that microvesicles have important roles in biofilm formation and intercellular communication among bacteria. However, biofilm formation of Staphylococcus epidermidis, and its relation to microvesicle secretion, is poorly understood because of the difficulty required to preserve the delicate water-rich morphology of biofilm for high-resolution observations. Here, we successfully imaged the microvesicles secreted from Staphylococcus epidermidis and the subsequent process of their integration into biofilm using liquid-phase imaging using atmospheric scanning electron microscopy (ASEM). In the biofilm, cells were connected by nanotube-like structures attached by microvesicles, and surrounded by extracellular polymeric substances. Cells cultured in the ASEM specimen holder were aldehyde-fixed and stained using positively charged nanogold labelling and/or using National Center for Microscopy and Imaging Research method. The samples immersed in aqueous radical scavenger glucose buffer were imaged by the inverted SEM of ASEM. Information regarding the morphologies of microvesicles, nanotube-like fibrils, and biofilm formed by Staphylococcus epidermidis is expected to be useful to elucidate the biological mechanism of biofilm formation and to develop a medicine against biofilms and their associated infections.}, } @article {pmid34669434, year = {2022}, author = {Chen, Y and Stewart, JIP and Liu, S and Sheppard, DC and Lu, L and Zhang, S}, title = {Spt20, a Structural Subunit of the SAGA Complex, Regulates Aspergillus fumigatus Biofilm Formation, Asexual Development, and Virulence.}, journal = {Applied and environmental microbiology}, volume = {88}, number = {1}, pages = {e0153521}, pmid = {34669434}, issn = {1098-5336}, support = {//FRQ | Fonds de Recherche du Québec - Santé (FRQS)/ ; 81361//Gouvernement du Canada | Canadian Institutes of Health Research (CIHR)/ ; 31770086//National Natural Science Foundation of China (NSF)/ ; 31470193//National Natural Science Foundation of China (NSF)/ ; //Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)/ ; 123306//CIHR/Canada ; FDN-159902//CIHR/Canada ; }, mesh = {*Aspergillus fumigatus/genetics ; *Biofilms ; *Fungal Proteins/genetics ; Virulence ; }, abstract = {The exopolysaccharide galactosaminogalactan (GAG) plays an important role in mediating adhesion, biofilm formation, and virulence in the pathogenic fungus Aspergillus fumigatus. Previous work showed that in A. fumigatus, the Lim domain-binding protein PtaB can form a complex with the sequence-specific transcription factor SomA for regulating GAG biosynthesis, biofilm formation, and asexual development. However, transcriptional coactivators required for biofilm formation in A. fumigatus remain uncharacterized. In this study, Spt20, an orthologue of the subunit of the Saccharomyces cerevisiae transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, was identified as a regulator of biofilm formation and asexual development in A. fumigatus. The loss of spt20 caused severe defects in the GAG biosynthesis, biofilm formation, conidiation, and virulence of A. fumigatus. RNA sequence data demonstrated that Spt20 positively regulates the expression of the GAG biosynthesis genes uge3 and agd3, the developmental regulator medA, and genes involved in the conidiation pathway. Moreover, more than 10 subunits of the SAGA complex (known from yeast) could be immunoprecipitated with Spt20, suggesting that Spt20 acts as a structural subunit of the SAGA complex. Furthermore, distinct modules of SAGA regulate GAG biosynthesis, biofilm formation, and asexual development in A. fumigatus to various degrees. In summary, the novel biofilm regulator Spt20 is reported, which plays a crucial role in the regulation of fungal asexual development, GAG biosynthesis, and virulence in A. fumigatus. These findings expand knowledge on the regulatory circuits of the SAGA complex relevant for the biofilm formation and asexual development of A. fumigatus. IMPORTANCE Eukaryotic transcription is regulated by a large number of proteins, ranging from sequence-specific DNA-binding factors to transcriptional coactivators (chromatin regulators and the general transcription machinery) and their regulators. Previous research indicated that the sequence-specific complex SomA/PtaB regulates the biofilm formation and asexual development of Aspergillus fumigatus. However, transcriptional coactivators working with sequence-specific transcription factors to regulate A. fumigatus biofilm formation remain uncharacterized. In this study, Spt20, an orthologue of the subunit of the Saccharomyces cerevisiae Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, was identified as a novel regulator of biofilm formation and asexual development in A. fumigatus. The loss of spt20 caused severe defects in galactosaminogalactan (GAG) production, conidiation, and virulence. Moreover, nearly all modules of the SAGA complex were required for the biofilm formation and asexual development of A. fumigatus. These results establish the SAGA complex as a transcriptional coactivator required for the biofilm formation and asexual development of A. fumigatus.}, } @article {pmid34669372, year = {2021}, author = {Tang, Y and Wang, T and Feng, J and Rong, F and Wang, K and Li, P and Huang, W}, title = {Photoactivatable Nitric Oxide-Releasing Gold Nanocages for Enhanced Hyperthermia Treatment of Biofilm-Associated Infections.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {43}, pages = {50668-50681}, doi = {10.1021/acsami.1c12483}, pmid = {34669372}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Female ; Gold/chemistry/*pharmacology ; Hyperthermia/*drug therapy ; Metal Nanoparticles/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Mice, Inbred Strains ; Microbial Sensitivity Tests ; Molecular Structure ; Nitric Oxide/chemistry/*pharmacology ; Particle Size ; Photochemical Processes ; Photothermal Therapy ; Surface Properties ; }, abstract = {With the increasing clinical use of invasive medical devices, various healthcare-associated infections (HAIs) caused by bacterial biofilm colonization of biomedical devices have posed serious threats to patients. The formation of biofilms makes it much more difficult and costly to treat infections. Here, we report a nitric oxide (NO)-releasing gold nanocage (AuNC@NO) that is stimulated by near-infrared (NIR) irradiation to deliver NO and generate hyperthermia for biofilm elimination. AuNC@NO was prepared by immobilizing a temperature-responsive NO donor onto gold nanocages (AuNCs) through thiol-gold interactions. AuNC@NO possesses stable and excellent photothermal conversion efficiency, as well as the characteristics of slow NO release at physiological temperature and on-demand quick NO release under NIR irradiation. Based on these features, AuNC@NO exhibits enhanced in vitro bactericidal and antibiofilm efficacy compared with AuNCs, which could achieve 4 orders of magnitude bacterial reduction and 85.4% biofilm elimination under NIR irradiation. In addition, we constructed an implant biofilm infection model and a subcutaneous biofilm infection model to evaluate the anti-infective effect of AuNC@NO. The in vivo results indicated that after 5 min of 0.5 W cm[-2] NIR irradiation, NO release from AuNC@NO was significantly accelerated, which induced the dispersal of methicillin-resistant Staphylococcus aureus (MRSA) biofilms and synergized with photothermal therapy (PTT) to kill planktonic MRSA that had lost its biofilm protection. Meanwhile, the surrounding tissues showed little damage because of controlled photothermal temperature and toxicity. In view of the above-mentioned results, the AuNC@NO nanocomposite developed in this work reveals potential application prospects as a useful antibiofilm agent in the field of biofilm-associated infection treatment.}, } @article {pmid34668851, year = {2021}, author = {Wang, H and Shi, Y and Chen, J and Wang, Y and Wang, Z and Yu, Z and Zheng, J and Shang, Y}, title = {The antiviral drug efavirenz reduces biofilm formation and hemolysis by Staphylococcus aureus.}, journal = {Journal of medical microbiology}, volume = {70}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001433}, pmid = {34668851}, issn = {1473-5644}, mesh = {Alkynes/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Benzoxazines/*pharmacology ; Biofilms/*drug effects ; Cyclopropanes/*pharmacology ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects ; Virulence/*drug effects ; }, abstract = {Introduction. Biofilm formation and hemolysis are closely related to the pathogenicity of Staphylococcus aureus.Hypothesis/Gap Statement. Strategies that reduce the mortality of S. aureus infections may involve novel antimicrobials and/or drugs that decrease S. aureus virulence, such as biofilm formation. The antiviral drug efavirenz is a non-nucleoside reverse transcriptase inhibitor, which also has shown antibacterial effect on Bacillus subtilis and Escherichia coli. Its effect on pathogen virulence has not yet been explored.Aim. This study investigates the antimicrobial and anti-virulence effect of efavirenz on S. aureus.Methodology. Biofilm biomasses were detected by crystal violet staining. Hemolysis activities of S. aureus were determined by rabbit erythrocytes lysis assay. RNA levels of transcriptional regulatory genes, biofilm-related genes, and virulence-related genes of S. aureus were determined by RT-qPCR.Results. Efavirenz showed an inhibitory effect on the growth of S. aureus, Enterococcus faecalis and Streptococcus agalactiae at 50 µM. Efavirenz significantly inhibited biofilm formation of both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) at 25 µM, but did not affect the growth of planktonic S. aureus cells. Moreover, hemolysis by S. aureus was inhibited by efavirenz at 25 µM. The expression levels of RNA transcriptional regulatory genes (agrA, agrC, sigB, saeR and saeS), biofilm-related genes (cidA, clfA, clfB, fnbA, fnbB), and virulence-related genes (hla, hld, staphopain B, alpha-3 PSM, beta PSM, delta PSM) of S. aureus decreased significantly at 25 µM efavirenz.Conclusion. Efavirenz inhibits S. aureus biofilm formation and virulence in vitro.}, } @article {pmid34668087, year = {2021}, author = {Vijayakumar, K and MuhilVannan, S}, title = {3, 5-Di-tert-butylphenol combat against Streptococcus mutans by impeding acidogenicity, acidurance and biofilm formation.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {12}, pages = {202}, pmid = {34668087}, issn = {1573-0972}, mesh = {Acids/*metabolism ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Down-Regulation/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/genetics ; Glucans ; Glucosyltransferases ; Humans ; Hydrogen Peroxide ; Hydrophobic and Hydrophilic Interactions ; Lactic Acid ; Phytochemicals/pharmacology ; Streptococcus mutans/*drug effects/genetics/*metabolism ; Virulence Factors/genetics/metabolism ; }, abstract = {Streptococcus mutans is a common pathogen present in the oral cavity and it causes dental caries for all aged groups of people, in particular, children. S. mutans have several virulence factors such as acidogenecity, aciduricity, adhesion and biofilm formation. These virulence factors are working together and lead to the development of caries in the tooth surface. The present study aimed to investigate the anticariogenic potential of 3, 5-di-tert-butylphenol (3, 5-DTBP) against S. mutans. 3, 5-DTBP biofilm inhibitory concentration (BIC) was found at 100 µg/ml concentration without any lethal effect on the growth. Moreover, 3, 5-DTBP significantly reduced water soluble and water insoluble glucans production, in concurrence with downregulation of gtfBC genes. Moreover, acidogenicity associated virulence factors such as lactate dehydrogenase and enolase enzymatic production was arrested upon 3, 5-DTBP treatment. In addition, 3, 5-DTBP greatly reduced acidtolerance ability through impedes of F1F0-ATPase. Gene expression analysis unveiled the downregulation of gtfB, gtfC, gtfD, vicRK, comDE, gbpB, smu0630 and relA upon 3, 5-DTBP treatment. The present study paves the way for exhibiting 3, 5-DTBP as a promising therapeutic agent to control S. mutans infections.}, } @article {pmid34667187, year = {2021}, author = {D'Arpa, P and Karna, SLR and Chen, T and Leung, KP}, title = {Pseudomonas aeruginosa transcriptome adaptations from colonization to biofilm infection of skin wounds.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {20632}, pmid = {34667187}, issn = {2045-2322}, mesh = {Animals ; Biofilms/growth & development ; Pseudomonas Infections/*genetics ; Pseudomonas aeruginosa/*genetics ; Rabbits ; Soft Tissue Injuries/microbiology ; Transcriptome/genetics ; Wound Healing/*genetics ; Wound Infection/microbiology ; }, abstract = {In burn patients Pseudomonas aeruginosa infection is a major cause of morbidity. Analysis of the pathogen's gene expression as it transitions from colonization to acute and then biofilm wound infection may provide strategies for infection control. Toward this goal, we seeded log-phase P. aeruginosa (PAO1) into 3-day-old, full-thickness excision wounds (rabbit ear) and harvested the bacteria during colonization (Hrs 2 and 6), acute infection (Hr 24), and biofilm infection (Days 5 and 9) for transcriptome analysis (RNA-Seq). After 2-6 h in the wound, genes for metabolism and cell replication were down-regulated while wound-adaptation genes were up-regulated (vs. expression in log-phase culture). As the infection progressed from acute to biofilm infection, more genes became up-regulated than down-regulated, but the down-regulated genes enriched in more pathways, likely because the genes and pathways that bacteria already colonizing wounds up-regulate to establish biofilm infection are less known. Across the stages of infection, carbon-utilization pathways shifted. During acute infection, itaconate produced by myeloid cells appears to have been a carbon source because myeloid cell infiltration and the expression of the host gene, ACOD1, for itaconate production peaked coincidently with the expression of the PAO1 genes for itaconate transport and catabolism. Additionally, branched-chain amino acids are suggested to be a carbon source in acute infection and in biofilm infection. In biofilm infection, fatty acid degradation was also up-regulated. These carbon sources feed into the glyoxylate cycle that was coincidently up-regulated, suggesting it provided the precursors for P. aeruginosa to synthesize macromolecules in establishing wound infection.}, } @article {pmid34666263, year = {2021}, author = {Torkzadeh, H and Cates, EL}, title = {Biofilm growth under continuous UVC irradiation: Quantitative effects of growth conditions and growth time on intensity response parameters.}, journal = {Water research}, volume = {206}, number = {}, pages = {117747}, doi = {10.1016/j.watres.2021.117747}, pmid = {34666263}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; *Disinfection ; Sanitary Engineering ; *Ultraviolet Rays ; }, abstract = {Biofilms can harbor a wide range of microorganisms, including opportunistic respiratory pathogens, and their establishment on engineered surfaces poses a risk to public health and industry. The emergence of compact germicidal ultraviolet light-emitting diodes (UV LEDs) may enable their incorporation into confined spaces to inhibit bacterial surface colonization on inaccessible surfaces, such as those in premise plumbing. Such applications necessitate knowledge of the quantitative response of biofilm growth rates to UV exposure on continuously irradiated surfaces. Herein, we performed experiments at varying flow cell temperatures in order to control baseline biofilm growth rates in the absence of UV; then, biofilm growth was compared under the same conditions but with simultaneous UVC irradiation. The inhibiting effect of UV irradiation on biofilm growth kinetics was diminished by more favorable growth conditions (higher temperature). Increasing the temperature by 10 °C resulted in an increase in biovolume by 193% under a UVC (254 nm) intensity of ∼60 µW/cm[2]. We further fitted an existing intensity response model to the biofilm growth data and analyzed the effects of temperature on model parameters, which were consistent with a hypothesized shielding effect arising from the deposition of extracellular colloidal materials. The shielding effect was found to result in breakthrough behavior of irradiated biofilms after 48 h, wherein accumulation of shielding substances eventually enabled biofilm establishment at even relatively high irradiation intensities (102.3 µW/cm[2]). With respect to applications of UVC irradiation for biofilm prevention, these results imply that surfaces more prone to bacterial colonization require disproportionately higher-intensity UVC irradiation for prevention of biofilm establishment, and continuous surface irradiation may be inadequate as a sole intervention for biofilm prevention in many scenarios.}, } @article {pmid34666180, year = {2022}, author = {Garcia, DR and Berns, EM and Spake, CSL and Mayfield, C and Dockery, DM and Vishwanath, N and Leong, J and Glasser, J and Barrett, C and Green, A and Antoci, V and Daniels, AH and Born, CT}, title = {Silver carboxylate-doped titanium dioxide-polydimethylsiloxane coating decreases Cutibacterium acnes adherence and biofilm formation on polyether ether ketone.}, journal = {The spine journal : official journal of the North American Spine Society}, volume = {22}, number = {3}, pages = {495-503}, doi = {10.1016/j.spinee.2021.09.011}, pmid = {34666180}, issn = {1878-1632}, mesh = {Benzophenones ; Biofilms ; Coated Materials, Biocompatible ; Dimethylpolysiloxanes ; Ethers ; Humans ; Ketones ; Polymers ; *Silver ; *Titanium ; }, abstract = {BACKGROUND CONTEXT: Cutibacterium acnes (C. acnes) is a gram-positive facultative anaerobe found in the deep sebaceous follicles of the skin on the shoulder and back. C. acnes has been increasingly recognized as a pathogen in spinal surgical site infection (SSI) especially in the presence of instrumentation.

PURPOSE: This study assesses whether a silver carboxylate-doped titanium dioxide-polydimethylsiloxane (TiO2-PDMS) coating can decrease C. acnes adherence and biofilm formation on PEEK and four other commonly used spinal implant materials, stainless steel, cobalt chromium, titanium, and titanium alloy.

STUDY DESIGN: We compared the adherence of C. acnes over 24 hours between uncoated, 95:5 TiO2 to PDMS ratio with 10× silver carboxylate coating and a 100% silver carboxylate coating on each implant material, which were uniformly saw cut and sterilized. Implants were then subjected to scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM).

METHODS: Samples were coated using 95:5 TiO2-PDMS 10× silver carboxylate, 100% silver carboxylate, or left uncoated. C. acnes was applied onto the samples and allowed to adhere for periods of 4, 8, 12, 16, or 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total of 24 hours. SEM and confocal laser scanning microscope were used to visualize all samples for the presence of biofilm and quantification of C. acnes adherence at each time point.

RESULTS: The 95:5 TiO2-PDMS 10× silver carboxylate coating was able to significantly decrease C. acnes adherence on PEEK after 8, 12, 16, and 20 hours of adherence. No statistical difference was found between the 95:5 TiO2-PDMS 10× silver carboxylate coating and the 100% silver carboxylate positive control. We previously observed extensive C. acnes biofilm formation on uncoated PEEK, but none on PEEK coated with either the 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating . Furthermore, no biofilm formation was observed on stainless steel, cobalt chromium, titanium, and titanium alloy coated with 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating.

CONCLUSION: A 95:5 TiO2-PDMS 10× silver carboxylate coating decreases C. acnes adhesion and prevents biofilm formation on PEEK and other common orthopedic implant materials.

CLINICAL SIGNIFICANCE: A 95:5 TiO2-PDMS 10× silver carboxylate coating may help decrease spinal SSI due to C. acnes, especially in procedures with instrumentation.}, } @article {pmid34665766, year = {2021}, author = {Anversa, L and Lara, BR and Romani, CD and Saeki, EK and Nogueira Nascentes, GA and Bonfietti, LX and Melhem, MSC and da Silva Ruiz, L and Camargo, CH and Pereira, VBR}, title = {Fungi in dialysis water and dialysate: occurrence, susceptibility to antifungal agents and biofilm production capacity.}, journal = {Journal of water and health}, volume = {19}, number = {5}, pages = {724-735}, doi = {10.2166/wh.2021.204}, pmid = {34665766}, issn = {1477-8920}, mesh = {*Antifungal Agents/pharmacology ; Biofilms ; Dialysis ; *Dialysis Solutions ; Fungi ; Microbial Sensitivity Tests ; Renal Dialysis ; Water ; }, abstract = {The aim of this study was to investigate the occurrence of fungi in dialysis water and dialysate, in addition to evaluating the susceptibility to antifungals and the biofilm production capacity of isolated microorganisms. The samples were collected in three hemodialysis units in Bauru (Brazil), every 15 days (July 2017-June 2018) at post-reverse osmosis, reuse, and dialysate points. The fungi were isolated by spread plate on Sabouraud dextrose agar. Filamentous fungi were phenotypically identified and yeasts were subjected to molecular evaluation of the ITS region. Susceptibility test to antifungals was carried out by the broth microdilution method and biofilm production capacity was evaluated in microtiter plates using crystal violet staining. Fungi were isolated in 52/216 (24.1%) samples, with an average count of 16.3 (10-40) CFU/mL. Overall, 61 microorganisms were identified, with 54 (88.5%) filamentous fungi and 7 (11.5%) yeasts. The main genera included were Penicillium, Cladosporium, Scedosporium, Rhinocladiella, Fusarium, and Emmonsia. Most isolates showed high values of minimum inhibitory concentration for 5-flucytosine and fluconazole and 35/45 (77.8%) isolates were classified as strong producers of biofilm. In order to increase the safety of the dialysis process, the adoption of control measures and monitoring of fungi in hemodialysis fluids is suggested.}, } @article {pmid34665259, year = {2021}, author = {Carvalho, SM and Freitas, CS and Oliveira, AS and Saraiva, LM}, title = {Staphylococcus aureus flavohaemoglobin contributes to early stage biofilm development under nitrosative stress.}, journal = {FEMS microbiology letters}, volume = {368}, number = {18}, pages = {}, doi = {10.1093/femsle/fnab131}, pmid = {34665259}, issn = {1574-6968}, mesh = {Humans ; Staphylococcus aureus/genetics ; Nitrosative Stress ; *Methicillin-Resistant Staphylococcus aureus ; Nitric Oxide ; Biofilms ; *Staphylococcal Infections ; }, abstract = {Staphylococcus aureus is a Gram-positive bacterium with capacity to form biofilms, which constitute an important resistance mechanism and virulence factor. Flavohaemoglobin (Hmp) is a major nitric oxide (NO) detoxifier of several bacteria, including S. aureus. Although Hmp has a well-known physiological role linked to response of planktonic cells to nitrosative stress, its contribution to biofilm formation remains unaddressed. Hence, in this work, we investigated the role of Hmp in biofilm development of a methicillin-resistant S. aureus strain. For this purpose, we exposed the hmp mutant to nitrosative stress and examined its behaviour along biofilm development. We observed that cells inactivated in hmp and grown under nitrosative stress conditions have significantly impaired capacity to develop early stage biofilms. Furthermore, the wild-type biofilm phenotype was fully restored by trans-complementation of hmp in the hmp mutant. Coculture studies of NO-producing macrophages with S. aureus revealed that the hmp mutant has significantly lower capacity to develop biofilm biomass when compared with the wild type. Thus, we concluded that the pathogen S. aureus relies on Hmp to establish viable biofilms in the presence of cells of the host innate immune system.}, } @article {pmid34665117, year = {2021}, author = {Shi, M and Zheng, Y and Wang, X and Wang, Z and Yang, M}, title = {Two regulatory factors of Vibrio cholerae activating the mannose-sensitive haemagglutinin pilus expression is important for biofilm formation and colonization in mice.}, journal = {Microbiology (Reading, England)}, volume = {167}, number = {10}, pages = {}, doi = {10.1099/mic.0.001098}, pmid = {34665117}, issn = {1465-2080}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cell Membrane/metabolism ; Cholera/microbiology ; Fimbriae Proteins/*genetics/metabolism ; Gene Expression Regulation, Bacterial ; Mannose-Binding Lectin/genetics/metabolism ; Mice ; Mutation ; Operon ; Promoter Regions, Genetic ; Vibrio cholerae/genetics/metabolism/*pathogenicity ; Virulence/genetics ; }, abstract = {Vibrio cholerae the causative agent of cholera, uses a large number of coordinated transcriptional regulatory events to transition from its environmental reservoir to the host intestine, which is its preferred colonization site. Transcription of the mannose-sensitive haemagglutinin pilus (MSHA), which aids the persistence of V. cholerae in aquatic environments, but causes its clearance by host immune defenses, was found to be regulated by a yet unknown mechanism during the infection cycle of V. cholerae. In this study, genomic expression library screening revealed that two regulators, VC1371 and VcRfaH, are able to positively activate the transcription of MSHA operon. VC1371 is localized and active in the cell membrane. Deletion of vc1371 or VcrfaH genes in V. cholerae resulted in less MshA protein production and less efficiency of biofilm formation compared to that in the wild-type strain. An adult mouse model showed that the mutants with vc1371 or VcrfaH deletion colonized less efficiently than the wild-type; the VcrfaH deletion mutant showed less colonization efficiency in the infant mouse model. The findings strongly suggested that the two regulators, namely VC1371 and VcRfaH, which are involved in the regulation of MSHA expression, play an important role in V. cholerae biofilm formation and colonization in mice.}, } @article {pmid34665111, year = {2021}, author = {Sultan, AM and Amer, GF and Nabiel, Y}, title = {Quinolone-resistant uropathogenic E. coli: is there a relation between qnr genes, gyrA gene target site mutation and biofilm formation?.}, journal = {Journal of medical microbiology}, volume = {70}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001432}, pmid = {34665111}, issn = {1473-5644}, mesh = {Biofilms/*growth & development ; Drug Resistance, Bacterial/*genetics ; Escherichia coli Infections/*microbiology ; Escherichia coli Proteins/*genetics ; Humans ; Urinary Tract Infections/*microbiology ; *Uropathogenic Escherichia coli/genetics/growth & development ; }, abstract = {Introduction. The resistance to quinolone reported in uropathogenic Escherichia coli (UPEC) is commonly caused by mutations in the target site encoding genes such as the gyrA gene. Bacterial plasmids carrying resistance genes such as qnr genes can also transfer resistance. Biofilms produced by UPEC can further aid the development of resistant urinary tract infections (UTIs).Hypothesis. Biofilm production is associated with higher prevalence of quinolones resistance genetic determinants.Aim. To detect the prevalence of qnr genes and gyrA gene mutation among quinolone-resistant UPEC and to investigate the relation between these genetic resistance determinants and biofilm production.Methodology. Catheterized urine samples were collected from 420 patients with evidence of UTIs and processed using standard techniques. Isolated UPEC were screened for quinolone resistance using an antimicrobial susceptibility test. Biofilm production among quinolone-resistant isolates was detected using the tissue culture plate method. All quinolone-resistant isolates were screened for qnr genes (qnrA, qnrB and qnrS) by multiplex PCR and for gyrA gene mutation by PCR-RFLP.Results. Two hundred and sixty-four UPEC isolates were detected from 420 processed urine samples. Out of the identified 264 UPEC, 123 (46.6 %) isolates were found to be quinolone-resistant, showing resistance to 1 or more of the tested quinolones. Of the 123 quinolone-resistant UPEC detected, 71(57.7 %) were biofilm producers. The qnr genes were detected among 62.6 % of the quinolone-resistant UPEC, with an estimated prevalence of 22.8, 32.5 and 37.4 % for qnrA, qnrB and qnrS genes, respectively. Additionally, the gyrA gene mutation was identified among 53.7 % of the quinolone-resistant isolates. We reported a significant association between biofilm production and the presence of qnrA, qnrB and qnrS genes. Furthermore, the gyrA gene mutation was significantly associated with biofilm-producing isolates. The coexistence of qnr genes, gyrA gene mutation and biofilm production was demonstrated in almost 40 % of the quinolone-resistant isolates.Conclusions. A significantly higher prevalence of qnr genes (qnrA, qnrB and qnrS) as well as the gyrA gene mutation was found among biofilm-forming UPEC. The reported coexistence of these different resistance mechanisms could aggravate quinolone resistance. Therefore, monitoring of resistance mechanisms and a proper stewardship programme are necessary.}, } @article {pmid34664132, year = {2022}, author = {Dos Santos, DDL and Besegato, JF and de Melo, PBG and Junior, JAO and Chorilli, M and Deng, D and Bagnato, VS and de Souza Rastelli, AN}, title = {Effect of curcumin-encapsulated Pluronic[®] F-127 over duo-species biofilm of Streptococcus mutans and Candida albicans.}, journal = {Lasers in medical science}, volume = {37}, number = {3}, pages = {1775-1786}, pmid = {34664132}, issn = {1435-604X}, mesh = {Biofilms ; Candida albicans ; *Curcumin/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Poloxamer/pharmacology ; Streptococcus mutans ; }, abstract = {To assess the effect of curcumin-encapsulated Pluronic[®] F-127 (Cur-Plu) during antimicrobial photodynamic therapy (aPDT) over duo-species biofilm of Streptococcus mutans and Candida albicans. Thermal analysis, optical absorption, and fluorescence spectroscopy were evaluated. Minimum inhibitory concentration (MIC) and minimum bactericidal/fungal concentration were obtained. The biofilms were cultured for 48 h at 37 °C and treated according to the groups: P + M + L + (photosensitizer encapsulated with Pluronic[®] F-127 + light); P + D + L + (photosensitizer incorporated in 1% DMSO + light); P - M + L + (no Pluronic[®] F-127 + light); P - D + L + (1% DMSO + light); P - L + (Milli-Q water + light); P + M + L - (photosensitizer encapsulated with Pluronic[®] F-127 no light); P + D + L - (photosensitizer in 1% DMSO, no light); P - M + L - (Pluronic[®] F-127 no light); P - D + L - (1% DMSO, no light); P - L - (Milli-Q water, no light; negative control group); CHX (0.2% chlorhexidine, positive control group); and NYS (Nystatin). Dark incubation of 5 min was used. The groups that received aPDT were irradiated by blue LED (460 nm, 15 J/cm[2]). Cell viability of the biofilms was performed by colony-forming units (CFU/mL) and confocal microscopy. Two-way ANOVA followed by Tukey's post hoc test was used at a significance level of 5%. P + D + L + and P + M + L + groups exhibited better log-reduction for both Candida albicans and Streptococcus mutans biofilms than P - M + L + , P - L + , and P - D + L + experimental groups. Furthermore, P + M + L + and P + D + L + showed greater reduction for Candida albicans than for Streptococcus mutans. aPDT mediated by Cur-Plu can be a potential strategy for biofilm control against duo-species biofilm of Streptococcus mutans and Candida albicans.}, } @article {pmid34663186, year = {2021}, author = {Žiemytė, M and Carda-Diéguez, M and Rodríguez-Díaz, JC and Ventero, MP and Mira, A and Ferrer, MD}, title = {Real-time monitoring of Pseudomonas aeruginosa biofilm growth dynamics and persister cells' eradication.}, journal = {Emerging microbes & infections}, volume = {10}, number = {1}, pages = {2062-2075}, pmid = {34663186}, issn = {2222-1751}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/growth & development ; Ciprofloxacin/pharmacology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Mutation ; Polymorphism, Single Nucleotide ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/genetics/growth & development/*physiology ; Staining and Labeling ; }, abstract = {Biofilm formation and the appearance of persister cells with low metabolic rates are key factors affecting conventional treatment failure and antibiotic resistance. Using impedance-based measurements, crystal violet staining and traditional culture we have studied the biofilm growth dynamics of 13 Pseudomonas aeruginosa strains under the effect of seven conventional antibiotics. Real-time growth quantifications revealed that the exposure of established P. aeruginosa biofilms to certain concentrations of ciprofloxacin, ceftazidime and tobramycin induced the emergence of persister cells, that showed different morphology and pigmentation, as well increased antibiotic resistance. Whole-genome sequencing of wildtype and persister cells identified several SNPs, a genomic inversion and a genomic duplication in one of the strains. However, these mutations were not uniquely associated with persisters, suggesting that the persistent phenotype may be related to metabolic and transcriptional changes. Given that mannitol has been proposed to activate bacterial metabolism, the synergistic combination of mannitol and ciprofloxacin was evaluated on clinical 48 h P. aeruginosa biofilms. When administered at doses ≥320 mg/L, mannitol was capable of preventing persister cell formation by efficiently activating dormant bacteria and making them susceptible to the antibiotic. These results were confirmed using viable colony counting. As the tested ciprofloxacin-mannitol combination appeared to fully eradicate mature biofilms, we conclude that impedance-based biofilm diagnostics, which permits antibiotic susceptibility testing and the identification of persister cells, is of great potential for the clinical practice and could aid in establishing treatment breakpoints for emerging biofilm-related infections.}, } @article {pmid34663068, year = {2021}, author = {Beyer, CD and Thavalingam, S and Guseva, T and Schardt, L and Zimmermann, R and Werner, C and Dietze, P and Bandow, JE and Metzler-Nolte, N and Rosenhahn, A}, title = {Zwitterionic Peptides Reduce Accumulation of Marine and Freshwater Biofilm Formers.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {42}, pages = {49682-49691}, doi = {10.1021/acsami.1c13459}, pmid = {34663068}, issn = {1944-8252}, mesh = {Biofouling/*prevention & control ; Diatoms/*drug effects ; Fresh Water/microbiology ; Materials Testing ; Molecular Conformation ; Peptides/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Zwitterionic peptides are facile low-fouling compounds for environmental applications as they are biocompatible and fully biodegradable as their degradation products are just amino acids. Here, a set of histidine (H) and glutamic acid (E), as well as lysine (K) and glutamic acid (E) based peptide sequences with zwitterionic properties were synthesized. Both oligopeptides (KE)4K and (HE)4H were synthesized in d and l configurations to test their ability to resist the nonspecific adsorption of the proteins lysozyme and fibrinogen. The coatings were additionally tested against the attachment of the marine organisms Navicula perminuta and Cobetia marina as well as the freshwater bacterium Pseudomonas fluorescens on the developed coatings. While the peptides containing lysine performed better in protein resistance assays and against freshwater bacteria, the sequences containing histidine were generally more resistant against marine organisms. The contribution of amino acid-intrinsic properties such as side chain pKa values and hydrophobicity, as well as external parameters such as pH and salinity of fresh water and seawater on the resistance of the coatings is discussed. In this way, a detailed picture emerges as to which zwitterionic sequences show advantages in future generations of biocompatible, sustainable, and nontoxic fouling release coatings.}, } @article {pmid34662738, year = {2022}, author = {Li, Z and Ren, L and Qiao, Y and Li, X and Zheng, J and Ma, J and Wang, Z}, title = {Recent advances in membrane biofilm reactor for micropollutants removal: Fundamentals, performance and microbial communities.}, journal = {Bioresource technology}, volume = {343}, number = {}, pages = {126139}, doi = {10.1016/j.biortech.2021.126139}, pmid = {34662738}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Humans ; Membranes, Artificial ; *Microbiota ; Waste Disposal, Fluid ; Wastewater ; *Water Pollutants, Chemical/analysis ; }, abstract = {The occurrence of micropollutants (MPs) in water and wastewater imposes potential risks on ecological security and human health. Membrane biofilm reactor (MBfR), as an emerging technology, has attracted much attention for MPs removal from water and wastewater. The review aims to consolidate the recent advances in membrane biofilm reactor for MPs removal from the standpoint of fundamentals, removal performance and microbial communities. First, the configuration and working principles of MBfRs are reviewed prior to the discussion of the current status of the system. Thereafter, a comprehensive review of the MBfR performance for MPs elimination based on literature database is presented. Key information on the microbial communities that are of great significance for the removal performance is then synthesized. Perspectives on the future research needs are also provided in this review to ensure the development of MBfRs for more cost-effective elimination of MPs from water and wastewater.}, } @article {pmid34662191, year = {2022}, author = {Totten, KMC and Patel, R}, title = {Phage Activity against Planktonic and Biofilm Staphylococcus aureus Periprosthetic Joint Infection Isolates.}, journal = {Antimicrobial agents and chemotherapy}, volume = {66}, number = {1}, pages = {e0187921}, pmid = {34662191}, issn = {1098-6596}, support = {UM1 AI104681/AI/NIAID NIH HHS/United States ; T32 AR056950/AR/NIAMS NIH HHS/United States ; UL1 TR002377/TR/NCATS NIH HHS/United States ; R01 AR056647/AR/NIAMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Bacteriophages ; Biofilms ; Humans ; Plankton ; *Prosthesis-Related Infections/drug therapy/microbiology ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus ; }, abstract = {We recently reported the successful treatment of a case of periprosthetic joint infection (PJI) with phage. Phage activity against bacteria causing PJI has not been systematically evaluated. Here, we examined the in vitro activity of seven phages against 122 clinical isolates of Staphylococcus aureus recovered between April 1999 and February 2018 from subjects with PJI. Phages were assessed against planktonic and biofilm phenotypes. Activity of individual phages was demonstrated against up to 73% of bacterial isolates in the planktonic state and up to 100% of biofilms formed by isolates that were planktonically phage susceptible. Susceptibility to phage was not correlated with small-colony-variant phenotype for planktonic or biofilm bacteria; correlation between antibiotic susceptibility and planktonic phage susceptibility and between biofilm phage susceptibility and strength of biofilm formation were noted under select conditions. These results demonstrate that phages can infect S. aureus causing PJI in both planktonic and biofilm phenotypes, and thus are worthy of investigation as an alternative or addition to antibiotics in this setting.}, } @article {pmid34657737, year = {2022}, author = {Shelby, RD and Mar, P and Janzow, GE and Mashburn-Warren, L and Tengberg, N and Navarro, JB and Allen, JM and Wickham, J and Wang, Y and Bailey, MT and Goodman, SD and Besner, GE}, title = {Antibacterial and anti-inflammatory effects of Lactobacillus reuteri in its biofilm state contribute to its beneficial effects in a rat model of experimental necrotizing enterocolitis.}, journal = {Journal of pediatric surgery}, volume = {57}, number = {7}, pages = {1382-1390}, doi = {10.1016/j.jpedsurg.2021.09.001}, pmid = {34657737}, issn = {1531-5037}, support = {R01 GM123482/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Animals, Newborn ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Anti-Inflammatory Agents ; Biofilms ; Disease Models, Animal ; *Enterocolitis, Necrotizing/microbiology/prevention & control ; Histamine ; Humans ; Infant, Newborn ; *Infant, Newborn, Diseases ; *Limosilactobacillus reuteri ; *Probiotics/pharmacology/therapeutic use ; Rats ; }, abstract = {INTRODUCTION: Necrotizing enterocolitis (NEC) remains a significant surgical emergency in neonates. We have demonstrated the efficacy of Lactobacillus reuteri (Lr) in protecting against experimental NEC when administered as a biofilm by incubation with maltose loaded dextranomer microspheres. Lr possesses antimicrobial and anti-inflammatory properties. We developed mutant strains of Lr to examine the importance of its antimicrobial and anti-inflammatory properties in protecting the intestines from NEC.

METHODS: Premature rat pups were exposed to hypoxia/hypothermia/hypertonic feeds to induce NEC. To examine the importance of antimicrobial reuterin and anti-inflammatory histamine, pups received either native or mutant forms of Lr, in either its planktonic or biofilm states, prior to induction of NEC. Intestinal histology was examined upon sacrifice.

RESULTS: Compared to no treatment, administration of a single dose of Lr in its biofilm state significantly decreased the incidence of NEC (67% vs. 18%, p < 0.0001), whereas Lr in its planktonic state had no significant effect. Administration of reuterin-deficient or histamine-deficient forms of Lr, in either planktonic or biofilm states, resulted in significant loss of efficacy.

CONCLUSION: Antimicrobial and anti-inflammatory effects of Lr contribute to its beneficial effects against NEC. This suggests that both infectious and inflammatory components contribute to the etiology of NEC.}, } @article {pmid34657423, year = {2021}, author = {Chen, Z and Song, K and Shang, Y and Xiong, Y and Lyu, Z and Chen, J and Zheng, J and Li, P and Wu, Y and Gu, C and Xie, Y and Deng, Q and Yu, Z and Zhang, J and Qu, D}, title = {Selection and Identification of Novel Antibacterial Agents against Planktonic Growth and Biofilm Formation of Enterococcus faecalis.}, journal = {Journal of medicinal chemistry}, volume = {64}, number = {20}, pages = {15037-15052}, doi = {10.1021/acs.jmedchem.1c00939}, pmid = {34657423}, issn = {1520-4804}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Chlorocebus aethiops ; Dose-Response Relationship, Drug ; Enterococcus faecalis/*drug effects/growth & development ; Erythrocytes/drug effects ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; Vero Cells ; }, abstract = {YycFG, one of the two-component systems involved in the regulation of biofilm formation, has attracted increasing interest as a potential target of antibacterial and antibiofilm agents. YycG inhibitors for Staphylococcus aureus and Staphylococcus epidermidis have been developed, but Enterococcus faecalis remains underexplored. Herein, we selected and identified novel candidate molecules against E. faecalis targeting histidine kinase YycG using high-throughput virtual screening; six molecules (compound-16, -30, -42, -46, -59, and -62) with low cytotoxicity toward mammalian cells were verified as potential YycG inhibitors through an autophosphorylation test and binding kinetics. Compound-16 inhibited planktonic cells of E. faecalis, including the vancomycin- or linezolid-resistant strains. In contrast, compound-62 did not affect planktonic growth but significantly inhibited biofilm formation in static and dynamic conditions. Compound-62 combined with ampicillin could synergistically eradicate the biofilm-embedded viable bacteria. The study demonstrates that YycG inhibitors may be valuable approaches for the development of novel antimicrobial agents for difficult-to-treat bacterial infections.}, } @article {pmid34655354, year = {2021}, author = {Koibuchi, H and Fujii, Y and Sato'o, Y and Mochizuki, T and Yamada, T and Cui, L and Taniguchi, N}, title = {Correction to: Inhibitory effects of ultrasound irradiation on Staphylococcus epidermidis biofilm.}, journal = {Journal of medical ultrasonics (2001)}, volume = {48}, number = {4}, pages = {449-450}, doi = {10.1007/s10396-021-01146-7}, pmid = {34655354}, issn = {1613-2254}, } @article {pmid34653590, year = {2022}, author = {Zhang, H and Qian, Y and Fan, D and Tian, Y and Huang, X}, title = {Biofilm formed by Hansschlegelia zhihuaiae S113 on root surface mitigates the toxicity of bensulfuron-methyl residues to maize.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {292}, number = {Pt A}, pages = {118366}, doi = {10.1016/j.envpol.2021.118366}, pmid = {34653590}, issn = {1873-6424}, mesh = {Biofilms ; *Methylocystaceae ; Plant Roots ; Rhizosphere ; Soil Microbiology ; *Zea mays ; }, abstract = {Bensulfuron-methyl (BSM) residues in soil threaten the rotation of BSM-sensitive crops. Microbial biofilms formed on crop roots could improve the ability of microbes to survive and protect crop roots. However, the research on biofilms with the purpose of mitigating or even eliminating BSM damage to sensitive crops is very limited. In this study, one BSM-degrading bacterium, Hansschlegelia zhihuaiae S113, colonized maize roots by forming a biofilm. Root exudates were associated with increased BSM degradation efficiency with strain S113 in rhizosphere soil relative to bulk soil, so the interactions among BSM degradation, root exudates, and biofilms may provide a new approach for the BSM-contaminated soil bioremediation. Root exudates and their constituent organic acids, including fumaric acid, tartaric acid, and l-malic acid, enhanced biofilm formation with 13.0-22.2% increases, owing to the regulation of genes encoding proteins responsible for cell motility/chemotaxis (fla/che cluster) and materials metabolism, thus promoting S113 population increases. Additionally, root exudates were also able to induce exopolysaccharide production to promote mature biofilm formation. Complete BSM degradation and healthy maize growth were found in BSM-contaminated rhizosphere soil treated with wild strain S113, compared to that treated with loss-of-function mutants ΔcheA-S113 (89.3%, without biofilm formation ability) and ΔsulE-S113 (22.1%, without degradation ability) or sterile water (10.7%, control). Furthermore, the biofilm mediated by organic acids, such as l-malic acid, exhibited a more favorable effect on BSM degradation and maize growth. These results showed that root exudates and their components (such as organic acids) can induce the biosynthesis of the biofilm to promote BSM degradation, emphasizing the contribution of root biofilm in reducing BSM damage to maize.}, } @article {pmid34653536, year = {2021}, author = {Augustinho do Nascimento, C and Kim, RR and Ferrari, CR and de Souza, BM and Braga, AS and Magalhães, AC}, title = {Effect of sweetener containing Stevia on the development of dental caries in enamel and dentin under a microcosm biofilm model.}, journal = {Journal of dentistry}, volume = {115}, number = {}, pages = {103835}, doi = {10.1016/j.jdent.2021.103835}, pmid = {34653536}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cattle ; *Dental Caries/prevention & control ; Dental Enamel ; Dentin ; Humans ; *Stevia ; Streptococcus mutans ; Sweetening Agents/pharmacology ; *Tooth Demineralization/chemically induced ; }, abstract = {OBJECTIVE: This study compared the effect of commercial and pure sweetener containing stevia to that of aspartame, to sucrose and xylitol on the development of dental caries.

METHODS: 228 bovine enamel and root dentin were exposed to microcosm biofilm model using human saliva. From the 2[nd] to the 5[th] day, the samples were exposed daily to McBain saliva supplemented with 0.2% of the respective sweeteners/sugar, under 5% CO2 and 37 °C. The lactic acid and the colony-forming units (CFU) were quantified. The demineralization was analyzed by TMR. The data were compared statistically (Kruskal-Wallis/ Dunn, p<0.05).

RESULTS: Pure stevia, pure aspartame, xylitol and control were able to significantly reduce 92% of lactate production compared to sucrose. Stevia finn, aspartame finn and sucrose showed similar production of lactic acid (around 0.45±0.12 g/L and 0.67±0.18 g/L, for enamel and dentin, p<0.0001). With respect to total lactobacilli and S. mutans/S. sobrinus CFU, xylitol and control did not show growth on enamel, while CFU numbers were found in stevia finn, aspartame finn and sucrose groups for both tissues. Enamel and dentin demineralization was significantly reduced for xylitol, control, pure stevia and pure aspartame (85% and 83% reduction, respectively) compared to stevia finn, aspartame finn and sucrose, which in turn did not differ from each other (sucrose ΔZ: 2913.7 ± 646.7 vol%.µm for enamel and 3543.3 ± 432.5 vol%.µm for dentin).

CONCLUSIONS: Commercial sweeteners containing stevia and aspartame proved to be as cariogenic as sucrose, which may be due to the other components, since the pure forms were not cariogenic.

CLINICAL RELEVANCE: Our study showed that some commercial sweeteners (aspartame and stevia) are as cariogenic as sucrose, which may be due to the presence of lactose. The population should be advice about the presence of lactose in such brand names, to avoid their consume.}, } @article {pmid34651489, year = {2021}, author = {Zhang, G and Wan, Z and Wang, X and Huang, Y and Zhou, Y and Chen, Y and Lei, Y and Qiao, L}, title = {[In vivo study on the effects of intercellular adhesion operon of Staphylococcus epidermidis on the inflammation associated with bacteria-fungal mixed biofilm].}, journal = {Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery}, volume = {35}, number = {10}, pages = {1328-1335}, pmid = {34651489}, issn = {1002-1892}, mesh = {Animals ; *Biofilms ; Candida albicans ; Inflammation ; Operon ; Rabbits ; *Staphylococcus epidermidis/genetics ; }, abstract = {OBJECTIVE: To study the effect of intercellular adhesion (ica) operon of Staphylococcus epidermidis on the inflammation associated with mixed biofilm of Staphylococcus epidermidis and Candida albicans on endotracheal tube material in rabbits.

METHODS: The standard strains of Staphylococcus epidermidis RP62A (ica operon positive, positive group) and ATCC12228 (ica operon negative, negative group) were taken to prepare a bacterial solution with a concentration of 1×10 [6] CFU/mL, respectively. Then, the two bacterial solutions were mixed with the standard strain of Candida albicans ATCC10231 of the same concentration to prepare a mixed culture solution at a ratio of 1∶1, respectively. The mixed culture solution was incubated with endotracheal tube material for 24 hours. The formation of mixed biofilm on the surface of the material was observed by scanning electron microscope. Thirty New Zealand rabbits, aged 4-6 months, were divided into two groups (n=15), and the endotracheal tube materials of the positive group and the negative group that were incubated for 24 hours were implanted beside the trachea. The body mass of rabbits in the two groups was measured before operation and at 1, 3, and 7 days after operation. At 1, 3, and 7 days after operation, the levels of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), and monocytechemotactic protein 1 (MCP-1) were detected by using an ELISA test kit. At 7 days after operation, the formation of mixed biofilm on the surface of the endotracheal tube materials was observed by scanning electron microscope, the inflammation and infiltration of tissues around the materials were observed by HE staining, and the bacterial infections in heart, lung, liver, and kidney were observed by plate colony counting method.

RESULTS: Scanning electron microscope observation showed that the mixed biofilm structure was obvious in the positive group after 24 hours in vitro incubation, but no mixed biofilm formation was observed in the negative group. In vivo studies showed that there was no significant difference in body mass between the two groups before operation and at 1, 3, and 7 days after operation (P>0.05). Compared with the negative group, the levels of MCP-1 and IL-1β at 1 day, and the levels of IL-1β, MCP-1, IL-6, and TNF-α at 3 and 7 days in the positive group all increased, with significant differences (P<0.05). Scanning electron microscope observation showed that a large amount of Staphylococcus epidermis and mixed biofilm structure were observed in the positive group, and a very small amount of bacteria was observed in the negative group with no mixed biofilm structure. HE staining of surrounding tissue showed inflammatory cell infiltration in both groups, and neutrophils and lymphocytes were more in the positive group than in the negative group. There was no significant difference in the number of bacterial infections in heart and liver between the two groups (P>0.05). The number of bacterial infections in lung and kidney in the positive group was higher than that in negative group (P<0.05).

CONCLUSION: In the mixed infection of Staphylococcus epidermidis and Candida albicans, the ica operon may strengthen the structure of the biofilm and the spread of the biofilm in vivo, leading to increased inflammatory factors, and the bacteria are difficult to remove and persist.}, } @article {pmid34650538, year = {2021}, author = {Liu, N and Li, X and Wang, M and Zhang, F and Wang, C and Zhang, K and Wang, H and Xu, S and Hu, W and Gu, L}, title = {DexA70, the Truncated Form of a Self-Produced Dextranase, Effectively Disrupts Streptococcus mutans Biofilm.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {737458}, pmid = {34650538}, issn = {1664-302X}, abstract = {Billions of people suffer from dental caries every year in spite of the effort to reduce the prevalence over the past few decades. Streptococcus mutans is the leading member of a specific group of cariogenic bacteria that cause dental caries. S. mutans forms biofilm, which is highly resistant to harsh environment, host immunity, and antimicrobial treatments. In this study, we found that S. mutans biofilm is highly resistant to both antimicrobial agents and lysozyme. DexA70, the truncated form of DexA (amino acids 100-732), a dextranase in S. mutans, prevents S. mutans biofilm formation and disassembles existing biofilms within minutes at nanomolar concentrations when supplied exogenously. DexA70 treatment markedly enhances biofilm sensitivity to antimicrobial agents and lysozyme, indicating its great potential in combating biofilm-related dental caries.}, } @article {pmid34650438, year = {2021}, author = {Dong, J and Zhang, D and Li, J and Liu, Y and Zhou, S and Yang, Y and Xu, N and Yang, Q and Ai, X}, title = {Genistein Inhibits the Pathogenesis of Aeromonas hydrophila by Disrupting Quorum Sensing Mediated Biofilm Formation and Aerolysin Production.}, journal = {Frontiers in pharmacology}, volume = {12}, number = {}, pages = {753581}, pmid = {34650438}, issn = {1663-9812}, abstract = {Aeromonas hydrophila is an opportunistic pathogen that is responsible for a variety of infectious diseases both in human and animals, particularly aquatic animals. Moreover, the pathogen has become a foodborne pathogen by transmitting from seafood to human. The abuse of antibiotics in aquaculture results in the emergence of antibiotic resistance and treatment failure. Therefore, novel approaches are urgently needed for managing resistant A. hydrophila associated infections. Aerolysin, an essential virulence factor of pathogenic A. hydrophila strain, has been identified as target developing novel drugs against pathogenesis of A. hydrophila. In the present study, genistein, without anti-A. hydrophila activity, was identified that could decrease the production of aerolysin and biofilm formation at a dose-dependent manner. Transcription of aerolysin encoding gene aerA and quorum sensing related genes ahyI and ahyR was significantly down-regulated when co-cultured with genistein. Cell viability studies demonstrated that genistein could significantly improve aerolysin mediated A549 cell injury. Furthermore, genistein could provide a remarkable protection to channel catfish infected with A. hydrophila. These findings indicate that targeting quorum sensing and virulence can be a useful approach developing drugs against A. hydrophila infections in aquaculture. Moreover, genistein can be chosen as a promising candidate in developing drugs against A. hydrophila.}, } @article {pmid34649133, year = {2021}, author = {Nakase, K and Koizumi, J and Midorikawa, R and Yamasaki, K and Tsutsui, M and Aoki, S and Nasu, Y and Hirai, Y and Nakaminami, H and Noguchi, N}, title = {Cutibacterium acnes phylogenetic type IC and II isolated from patients with non-acne diseases exhibit high-level biofilm formation.}, journal = {International journal of medical microbiology : IJMM}, volume = {311}, number = {7}, pages = {151538}, doi = {10.1016/j.ijmm.2021.151538}, pmid = {34649133}, issn = {1618-0607}, mesh = {*Acne Vulgaris ; Biofilms ; Humans ; Phylogeny ; *Propionibacteriaceae ; Propionibacterium acnes/genetics ; }, abstract = {Cutibacterium (formerly Propionibacterium) acnes is an important for not only exacerbating factor of acne vulgaris but also pathogen of surgical site infections (SSIs) in orthopedics and plastic surgery. Although biofilm-forming (BF) C. acnes are associated with intractable SSI, characteristics of these strains were still unknown. Here, we explored detailed molecular epidemiological features of BF C. acnes isolated as causative pathogen of infectious diseases. Phylogenetic types of 205 C. acnes strains isolated between 2013 and 2018 from 18 clinical departments of a university hospital in Japan were determined by single-locus sequence type (SLST). Clade H (traditional type IC) and K (type II) which are less relevant with healthy skin and acne vulgaris, were detected in 26.8% (55/205) and 16.1% (33/205) of the strains, respectively. The incidence of them was significantly higher than that of acne patients (H and K, each 2.9%, P < 0.05). In addition, SLST distribution of C. acnes strains differed by each department and isolation site. When biofilm formation was quantified, 51 strains (24.9%) were defined as high-BF strains. Notably, most high-BF strains were classified into the strains of clade H (56.4%, 31/55) and clade K (54.4%, 18/33), and these strains were frequently found in the strains isolated from patients of medical emergency center and plastic surgery. Similarly, high-BF strains were frequently found among the isolates from blood (35.7%) and catheters (30.0%), with a high proportion belonging to clades H and K. Compared to C. acnes strains isolated from acne patients, antimicrobial-resistant strains were less identified in non-acne patients. Our findings showed that pathogenicity of C. acnes strains differs by their phylogenetic types. Furthermore, we showed clade H and K have the ability of high biofilm formation and suggest that these strains have potential to become a risk factor for SSI.}, } @article {pmid34649060, year = {2022}, author = {Chen, L and Wang, XD and Lee, DJ}, title = {Biofilm with highly heterogeneous interior structure for pollutant removal: Cell distribution and manipulated mass transport.}, journal = {Bioresource technology}, volume = {343}, number = {}, pages = {125913}, doi = {10.1016/j.biortech.2021.125913}, pmid = {34649060}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Diffusion ; *Environmental Pollutants ; Extracellular Polymeric Substance Matrix ; }, abstract = {Biofilm wastewater treatment had been applied in practice. Conventionally the biofilm was modeled as a uniform structure to simplify the analysis. This study for the first time established a three-dimensional biofilm model with distributions separating living cells, Extracellular polymeric substances (EPS) and pores, based on which the local fluid flow velocity and pollutant diffusion and reaction fluxes inside the biofilm were numerically evaluated. Both the uniform structured and previously proposed heterogeneous models had been confirmed to overestimate the performances of a biofilm for wastewater treatment. The survival strategies of living cells in biofilm were discussed. Besides exposing to fresh pollutants for maximizing pollutant uptake, the tendency to form small aggregates of cells for shortening diffusion length so furnishing the pollutant with reduced diffusional resistance to living cells was also for the first time noted. This communication advanced the knowledge to comprehend the detailed processes in biofilm.}, } @article {pmid34649049, year = {2022}, author = {Xiao, R and Zhu, W and Xu, S and Chai, W and Tong, Y and Zheng, P and Lu, H}, title = {Low strength wastewater anammox start-up by stepwise decrement in influent nitrogen: Biofilm formation mechanism and mathematical modelling.}, journal = {Environment international}, volume = {158}, number = {}, pages = {106929}, doi = {10.1016/j.envint.2021.106929}, pmid = {34649049}, issn = {1873-6750}, mesh = {Anaerobic Ammonia Oxidation ; Anaerobiosis ; Biofilms ; Bioreactors ; *Nitrogen ; Oxidation-Reduction ; Sewage ; *Wastewater ; }, abstract = {The application of mainstream anammox process is hampered by its overlong start-up and instability under disturbance. A lab-scale mainstream anammox moving bed biofilm reactor (MBBR) was successfully started in 120 days with stepwise decrement in influent nitrogen concentration from sidestream to mainstream condition. The initial colonization by Candidatus Jettenia and filamentous fermenter Anaerolineaceae were potentially mediated by hydrophobic interaction and type IV pilus. Ca. Kuenenia with higher substrate affinity outcompeted Ca. Jettenia, and the predominant fermenters shifted to fermentative Ignavibacteriaceae in the mature biofilm. A novel mainstream anammox biofilm development (MABD) model was constructed to describe biofilm growth, population dynamics, and nitrogen removal performance. The simulation results suggested that higher inocula biomass (460-690 mgVSS·L[-1]), relative abundance of low-affinity AnAOB in the inocula (e.g., Ca. Jettenia, 1.3-2%), and the early-stage solids retention time (45-68 days) were desired to form thicker biofilm and improve effluent quality during 120-day mainstream anammox MBBR start-up. The mechanistic insights into biofilm formation and predictive power of the newly developed MABD model are of importance to the design and operation of mainstream anammox processes towards more biofilm biomass and higher nitrogen removal efficiency.}, } @article {pmid34648180, year = {2022}, author = {Bowen, SH}, title = {Digestion and assimilation of benthic biofilm by the Sábalo, Prochilodus lineatus.}, journal = {Journal of fish biology}, volume = {100}, number = {1}, pages = {107-116}, doi = {10.1111/jfb.14924}, pmid = {34648180}, issn = {1095-8649}, mesh = {Animals ; Biofilms ; *Characiformes ; Diet ; Digestion ; Food ; }, abstract = {The Sábalo, Prochilodus lineatus (Valenciennes, 1837), is one of 270 fish species in the Rio Paraná system, and it comprises >50% of the fish biomass. Its diet is flocculant benthic biofilm comprised of algae, bacteria and non-living organic matter: a food resource apparently of little value to other fishes. Digestion and assimilation of key nutrients from its biofilm diet by P. lineatus were described and quantified in an attempt to discover how this species is so successful. The fish begin a feeding period with empty digestive tracts, accumulate food during the feeding period and then void the gut content at the end of the feeding period. Early in a feeding period, sand accumulates in the gizzard-like pyloric stomach where it serves as both a grinding medium and a sieve. After sufficient sand has been acquired, food particles passed from the pyloric stomach to the intestine are dramatically reduced in size to <20 μ maximum dimension, whereas larger particles including mineral matter and plant fibres are retained. Total ash, hydrolysis-resistant-ash and hydrolysis-resistant-organic-matter were tested as reference materials against which to measure assimilation and hydrolysis-resistant-organic matter best met the assumptions of the technique. Comparison of the first food ingested to food ingested later in the feeding period shows that grinding of food and selective retention of larger particles results in a three-fold increase in the assimilation of ash-free-dry-mass (to 56%) and hydrolysis-labile-organic-matter (to 67%), and a six-fold increase in the assimilation of amino acids (AAs; to 74%). When food quality is assessed in terms of g AA assimilated · kJ[-1] energy assimilated, the quality of food ingested by P. lineatus ranges from a maintenance level of 5 to 12 mg AA · kJ[-1] , a level expected to produce near maximum growth. Thus, the processing of food in the pyloric stomach is integral to the success of P. lineatus in establishing large populations on a diet of flocculent benthic biofilm.}, } @article {pmid34647135, year = {2021}, author = {Meng, KL and Lv, XC and Che, HY and Li, Y and Chen, XL and Hu, MX and Yan, M}, title = {Joint protection strategies for Saccharomyces boulardii: exogenous encapsulation and endogenous biofilm structure.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {21-22}, pages = {8469-8479}, pmid = {34647135}, issn = {1432-0614}, support = {LGN20C170002//Natural Science Foundation of Zhejiang Province/ ; 81700936//National Natural Science Foundation of China/ ; }, mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; *Probiotics ; *Saccharomyces boulardii ; Saccharomyces cerevisiae ; }, abstract = {Biofilms are heterogeneous structures composed of microorganisms and the surrounding extracellular polymeric substances (EPS) that protect the microbial cells from harsh environments. Saccharomyces boulardii is the first yeast classified as a probiotic strain with unique properties. However, tolerance of S. boulardii biofilms to harsh environments especially during production and in the gastrointestine remains unknown. In this study, S. boulardii cells were encapsulated in alginate microcapsules and subsequently cultured to form biofilms, and their survival and tolerance were evaluated. Microencapsulation provided S. boulardii a confined space that enhanced biofilm formation. The thick alginate shell and the mature biofilm improved the ability of S. boulardii to survive under harsh conditions. The exogenous encapsulation and the endogenous biofilm structure together enhanced the gastrointestinal tolerance and thermotolerance of S. boulardii. Besides, as the alginate shell became thinner with an increase in the subsequent culture duration, the EPS of S. boulardii biofilms exerted an important protective effect in resisting high temperatures. The encapsulated biofilm of S. boulardii after 24-h culture exhibited 60 × higher thermotolerance at 60 °C (10 min), while those after 6-h and 24-h culture showed 1000 × to 550,000 × higher thermotolerance at 120 °C (1 min) compared with the planktonic cells without encapsulation. The present study's findings suggest that a combination of encapsulation and biofilm mode efficiently enhanced gastrointestinal tolerance and thermotolerance of S. boulardii. KEY POINTS: • Encapsulated S. boulardii in biofilm mode showed enhanced tolerance. • Exogenous shell and endogenous biofilm provided dual protection to S. boulardii.}, } @article {pmid34646258, year = {2021}, author = {Liu, Y and Huang, Y and Fan, C and Chi, Z and Bai, M and Sun, L and Yang, L and Yu, C and Song, Z and Yang, X and Yi, J and Wang, S and Liu, L and Wang, G and Zheng, L}, title = {Ursolic Acid Targets Glucosyltransferase and Inhibits Its Activity to Prevent Streptococcus mutans Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {743305}, pmid = {34646258}, issn = {1664-302X}, abstract = {Streptococcus mutans (S. mutans), the prime pathogen of dental caries, can secrete glucosyltransferases (GTFs) to synthesize extracellular polysaccharides (EPSs), which are the virulence determinants of cariogenic biofilms. Ursolic acid, a type of pentacyclic triterpene natural compound, has shown potential antibiofilm effects on S. mutans. To investigate the mechanisms of ursolic acid-mediated inhibition of S. mutans biofilm formation, we first demonstrated that ursolic acid could decrease the viability and structural integrity of biofilms, as evidenced by XTT, crystal violet, and live/dead staining assays. Then, we further revealed that ursolic acid could compete with the inherent substrate to occupy the catalytic center of GTFs to inhibit EPS formation, and this was confirmed by GTF activity assays, computer simulations, site-directed mutagenesis, and capillary electrophoresis (CE). In conclusion, ursolic acid can decrease bacterial viability and prevent S. mutans biofilm formation by binding and inhibiting the activity of GTFs.}, } @article {pmid34643189, year = {2021}, author = {Zhang, J and Yang, J and Li, Q and Ding, J and Liu, L and Sun, T and Li, H}, title = {Preparation of WPU-based super-amphiphobic coatings functionalized by in situ modified SiOx particles and their anti-biofilm mechanism.}, journal = {Biomaterials science}, volume = {9}, number = {22}, pages = {7504-7521}, doi = {10.1039/d1bm01285a}, pmid = {34643189}, issn = {2047-4849}, mesh = {Bacterial Adhesion ; Biofilms ; *Biofouling ; Hydrophobic and Hydrophilic Interactions ; *Polyurethanes ; }, abstract = {Fabrication of anti-wetting coatings with anti-biofouling and anti-biofilm properties has become a hot spot of attention in recent years. However, the anti-biofilm mechanism of anti-bacterial adhesion coatings with different wet resistance properties has not been explored in detail. In this work, SiOx micro-nano particles were prepared by the Stöber method and were in situ modified. The SiOx/waterborne polyurethane (WPU) coatings were prepared by the drop coating method, and the coatings with different hydrophobic and oleophobic properties were constructed by modifying the process conditions using SiOx micro-nano particles as the roughness construction factor. Taking the dominant spoilage bacteria of aquatic products, Shewanella putrefaciens as the object, the anti-bacterial adhesion properties and anti-biofilm mechanism of the SiOx/WPU coatings were investigated. The results show that, with the unmodified SiOx particles increasing from 1.2% (w/V) to 4.0% (w/V), the hydrophobicity and thermal stability of the SiOx/WPU coatings are significantly enhanced, but the oil repellency becomes worse due to the mesoporous structure. After SiOx micro-nano particles are modified with 1H,1H,2H,2H-perfluorooctyl trichlorosilane (PFOTS), the surface energy of the SiOx/WPU coatings is decreased, the liquid repellency is improved, and the surfaces are rough with the appearance of fluorocarbon compounds, but the thermal stabilities are slightly reduced. Among them, after the secondary modification of SiOx micro-nano particles, the SiOx/WPU coatings showed excellent oil repellency, lower surface energies and higher fluorocarbon content on the surface. Particularly, SiOx/WPU coatings exhibited super-amphiphobicity after adjusting the amount of concentrated ammonia added during the secondary modification process. Meanwhile, we found that for the hydrophobic SiOx/WPU coatings, the stronger the oleophobic property, the greater the anti-bacterial adhesion ability is, while the anti-bacterial adhesion ability of hydrophobic and selectively oleophobic or superhydrophobic and oleophobic SiOx/WPU coatings is poor than that of amphiphilic SiOx/WPU coatings. However, because the super-amphiphobic SiOx/WPU coatings can be in the Cassie state with the bacterial solution for a long time, it can "capture" enough air to inhibit the irreversible adhesion of the bacteria. More importantly, the coatings can also inhibit the metabolic activity, secretion of extracellular polysaccharides, and activities of ATPase and AKP of the adherent bacteria, so it has a better anti-biofilm property. The anti-biofilm coatings can be used as food packaging materials or coated on the inner surface of packaging boxes to prevent the microbial infection.}, } @article {pmid34641398, year = {2021}, author = {Han, Q and Yan, X and Zhang, R and Wang, G and Zhang, Y}, title = {Juglone Inactivates Pseudomonas aeruginosa through Cell Membrane Damage, Biofilm Blockage, and Inhibition of Gene Expression.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {19}, pages = {}, pmid = {34641398}, issn = {1420-3049}, support = {NC1405 (2).//Xi'an City Science and Technology Planning Project/ ; 2015NY007//Shaanxi Provincial Agricultural Special Fund Project, Shaanxi Provincial Science and Technology Key Research Project/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Cell Membrane/*drug effects/pathology ; Cytotoxins/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Naphthoquinones/*pharmacology ; Polymers/metabolism ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism ; Quorum Sensing ; Virulence ; }, abstract = {Due to the strong drug resistance of Pseudomonas aeruginosa (P. aeruginosa), the inhibition effects of conventional disinfectants and antibiotics are not obvious. Juglone extracted from discarded walnut husk, as a kind of plant-derived antimicrobial agent, has the advantages of naturalness, high efficiency, and low residue, with a potential role in the inhibition of P. aeruginosa. This study elucidated the inhibitory effect of juglone on the growth of plankton and the formation of P. aeruginosa biofilm. The results showed that juglone (35 μg/mL) had an irreversible inhibitory effect on P. aeruginosa colony formation (about 10[7] CFU/mL). The integrity and permeability of the cell membrane were effectively destroyed, accompanied by disorder of the membrane permeability, mass leakage of the cytoplasm, and ATP consumption. Further studies manifested that juglone could induce the abnormal accumulation of ROS in cells and block the formation of the cell membrane. In addition, RT-qPCR showed that juglone could effectively block the expression of five virulence genes and two genes involved in the production of extracellular polymers, thereby reducing the toxicity and infection of P. aeruginosa and preventing the production of extracellular polymers. This study can provide support for the innovation of antibacterial technology toward P. aeruginosa in food.}, } @article {pmid34641178, year = {2021}, author = {Xu, X and Pang, J}, title = {Fabrication and Characterization of Composite Biofilm of Konjac Glucomannan/Sodium Lignosulfonate/ε-Polylysine with Reinforced Mechanical Strength and Antibacterial Ability.}, journal = {Polymers}, volume = {13}, number = {19}, pages = {}, pmid = {34641178}, issn = {2073-4360}, abstract = {In order to enforce the mechanical strength and antibacterial ability of biofilm and explore the underlying mechanism, sodium lignosulfonate (SL) and ε-polylysine (ε-PL) were introduced to fabricate the composite film of konjac glucomannan (KGM)/SL/ε-PL in the present study. According to our previous method, 1% (w/v) of KGM was the optimal concentration for the film preparation method, on the basis of which the amount of SL and ε-PL were screened by mechanical properties enforcement of film. The structure, mechanical performance and thermal stability of the film were characterized by SEM, FTIR, TGA and tensile strength tests. The optimized composite film was comprised of KGM 1% (w/v), SL 0.2% (w/v), and ε-PL 0.375% (w/v). The tensile strength (105.97 ± 4.58 MPa, p < 0.05) and elongation at break (95.71 ± 5.02%, p < 0.05) of the KGM/SL/ε-PL composite film was greatly improved compared with that of KGM. Meanwhile, the thermal stability and antibacterial property of film were also enhanced by the presence of SL and ε-PL. In co-culturation mode, the KGM/SL/ε-PL composite film showed good inhibitory effect on Escherichia coli (22.50 ± 0.31 mm, p < 0.05) and Staphylococcus aureus (19.69 ± 0.36 mm, p < 0.05) by determining the inhibition zone diameter. It was revealed that KGM/SL/ε-PL composite film shows enhanced mechanical strength and reliable antibacterial activities and it could be a potential candidate in the field of food packaging.}, } @article {pmid34638591, year = {2021}, author = {Rodríguez-Merchán, EC and Davidson, DJ and Liddle, AD}, title = {Recent Strategies to Combat Infections from Biofilm-Forming Bacteria on Orthopaedic Implants.}, journal = {International journal of molecular sciences}, volume = {22}, number = {19}, pages = {}, pmid = {34638591}, issn = {1422-0067}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Bacteria/*drug effects ; Biofilms/*drug effects ; Humans ; Orthopedic Procedures/*adverse effects ; Orthopedics/methods ; Postoperative Complications/*microbiology ; Prostheses and Implants/*microbiology ; }, abstract = {Biofilm-related implant infections (BRII) are a disastrous complication of both elective and trauma orthopaedic surgery and occur when an implant becomes colonised by bacteria. The definitive treatment to eradicate the infections once a biofilm has established is surgical excision of the implant and thorough local debridement, but this carries a significant socioeconomic cost, the outcomes for the patient are often poor, and there is a significant risk of recurrence. Due to the large volumes of surgical procedures performed annually involving medical device implantation, both in orthopaedic surgery and healthcare in general, and with the incidence of implant-related infection being as high as 5%, interventions to prevent and treat BRII are a major focus of research. As such, innovation is progressing at a very fast pace; the aim of this study is to review the latest interventions for the prevention and treatment of BRII, with a particular focus on implant-related approaches.}, } @article {pmid34637911, year = {2022}, author = {Li, W and Zhen, Y and Li, N and Wang, H and Lin, M and Sui, X and Zhao, W and Guo, P and Lin, J}, title = {Sulfur transformation and bacterial community dynamics in both desulfurization-denitrification biofilm and suspended activated sludge.}, journal = {Bioresource technology}, volume = {343}, number = {}, pages = {126108}, doi = {10.1016/j.biortech.2021.126108}, pmid = {34637911}, issn = {1873-2976}, mesh = {Bacteria/genetics ; Biofilms ; Bioreactors ; *Denitrification ; Nitrogen ; *Sewage ; Sulfur ; }, abstract = {Types of microbial aggregates have essential effects on bacterial communities' characteristics, thus affecting the pollutants removal. An up-flow biofilm reactor was used to study the different performances of S[2-]/NO2[-] removal and functional genes in suspended sludge and biofilms. The metabolic pathways of sulfurous and nitrogenous pollutants in the desulfurization-denitrification process were proposed. The results showed that S[0] formation dominated the reactor with a high S[2-] concentration. Autotrophic Sulfurovum responsible for S[2-]/S[0] oxidation was the only dominant bacteria in suspended sludge. Heterotrophic Desulfocapsa responsible for SO4[2-] reduction coexisted with Sulfurovum and dominated in biofilms. S[2-] oxidation to S[0] was catalyzed via fccA/B and sqr genes in suspended sludge. S3[2-]/S[0] oxidation to SO4[2-] was catalyzed via dsrA/B gene in biofilms. SO4[2-] and NO2[-] were removed via the dissimilatory sulfate reduction and denitrification pathway, respectively. This work provides a fundamental and practical basis for optimizing suspended sludge/biofilm systems for S[2-]/NO2[-] removal.}, } @article {pmid34637696, year = {2021}, author = {Dai, W and Zhang, Y and Zhang, J and Xue, C and Yan, J and Li, X and Zheng, X and Dong, R and Bai, J and Su, Y and Xie, P and Zhong, W and Zhang, H and Yan, Z and Zhong, W and Song, Y}, title = {Analysis of antibiotic-induced drug resistance of Salmonella enteritidis and its biofilm formation mechanism.}, journal = {Bioengineered}, volume = {12}, number = {2}, pages = {10254-10263}, pmid = {34637696}, issn = {2165-5987}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; *Drug Resistance, Bacterial/drug effects/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Plankton/drug effects/genetics ; Salmonella enteritidis/drug effects/genetics/*physiology ; }, abstract = {This research was to explore antibiotic-induced drug resistance of Salmonella enteritidis and its biofilm formation mechanism. Kirby-Bauer (K-B) disk method recommended by Clinical and Laboratory Standards Institute (CLSI) was used to test drug sensitivity of Salmonella enteritidis to 16 kinds of antibiotics including ß-lactams, aminoglycosides, quinolones, sulfonamides, chloramphenicols, and tetracyclines. Polymerase chain reaction (PCR) was performed to detect carrying of drug resistance genes of 29 kinds of antibiotics including ß-lactams, aminoglycosides, quinolones, sulfonamides, chloramphenicols, and tetracyclines of Salmonella enteritidis. The expressions of esp, ebpA, ge1E, and fsrB genes in biofilm group and plankton group were detected when Salmonella was induced, and difference of gene expression was detected by FQ-PCR. The drug resistance rates of Salmonella enteritidis to nalidixic acid, ampicillin, streptomyces, and cefoperazone were high, which were 94.5%, 75%, 67%, and 52%, respectively. 94 strains of Salmonella enteritidis formed 22 kinds of drug resistance spectrum, the strains were generally resistant to 4-5 antibiotics, and some strains formed fixed drug resistance spectrum as follows: AMP-CFP-STR-NA-TE (22.6,21.7%), AMP-STR-NA-TE (17,16%), and AMP-CFP-STR-NA (11.1,10.6%). During biofilm formation, fsr can increase expression of ge1E and decrease expression of esp and ebpA. Consequently, Salmonella enteritidis was generally resistant to nalidixic acid, ampicillin, and streptomycin, and the multidrug resistance was severe. The drug resistance genes sul2, sul3, blaTEM-1-like, tet(A), and tet(G) were highly carried in Salmonella enteritidis. Esp, ebpA, ge1E, and fsrB genes were closely related to biofilm formation of Salmonella enteritidis.}, } @article {pmid34635886, year = {2021}, author = {Peng, D and Liu, G and He, Y and Gao, P and Gou, S and Wu, J and Yu, J and Liu, P and Cai, K}, title = {Fabrication of a pH-responsive core-shell nanosystem with a low-temperature photothermal therapy effect for treating bacterial biofilm infection.}, journal = {Biomaterials science}, volume = {9}, number = {22}, pages = {7483-7491}, doi = {10.1039/d1bm01329g}, pmid = {34635886}, issn = {2047-4849}, mesh = {*Bacterial Infections ; Biofilms ; Humans ; Hydrogen-Ion Concentration ; *Hyperthermia, Induced ; *Nanoparticles ; Photothermal Therapy ; Temperature ; }, abstract = {Recently, photothermal therapy (PTT) has been recognized as a viable alternative strategy against bacterial biofilm infection. However, the hyperthermia required for PTT to ablate a biofilm usually induces damage in normal tissues/organs nearby. Herein, we developed zeolite-based imidazole framework (ZIF-8)-coated mesoporous polydopamine (MPDA) core-shell nanoparticles and then loaded Pifithrin-μ (PES), a natural inhibitor of heat-shock protein (HSP) that plays an essential role in bacteria resisting heating-induced damage. The ZIF-8 shell of the MPDA@ZIF-8/PES nanoplatform enabled a rapid degradation in response to the acidic environment in bacterial biofilm infection, which triggered the controlled release of PES and Zn ions. As a result, HSP was remarkably suppressed for enhancing PTT efficacy upon mild near-infrared light irradiation. In addition, the release of Zn[2+] also had an antibacterial/antibiofilm effect. Thus, the fabricated nanosystem was able to induce the effective elimination of the bacterial biofilm, realizing low-temperature PTT (∼45 °C) with excellent antibacterial efficacy. This work presented here not only provides a facile approach to fabricate the MPDA@ZIF-8/PES nanosystem with the responsiveness of the bacterial infection environment, but also proposes a promising low-temperature PTT strategy to treat bacterial biofilm-infection effectively.}, } @article {pmid34635023, year = {2023}, author = {Chan, WL and Luo, L and Wu, H}, title = {The role of hygrodynamic resistance compared to biofilm formation in helping pathogenic bacteria dominate air-conditioning units recovered from odour problems.}, journal = {Environmental technology}, volume = {44}, number = {7}, pages = {1018-1026}, doi = {10.1080/09593330.2021.1992510}, pmid = {34635023}, issn = {1479-487X}, mesh = {*Biofilms ; *Odorants ; }, abstract = {We previsouly found that installing filters in odourous air-conditioning units (ACUs) to block the entry of skin squames could well tackle the odour problems. In this study, we revisited and sampled the ACUs installed with filters earlier to study the bacterial communities inside the ACUs using 16S amplicon sequencing. We identified 26 genera and found that the skin bacteria isolated in the previous work were absent in this study. Two pathogenic bacteria, Methylobacterium and Sphingomonas, dominated ACUs instead. Afterwards, these two bacteria were identified to species level (Methylobacterium organophilum and Sphingomonas paucimobilis, respectively), and examined in terms of their biofilm formation ability and resistance to changing moisture conditions together with another prevalent species isolated in our previous study, namely Micrococcus luteus, in order to understand the mechanisms of the survival of bacteria in ACUs. In general, M. organophilum and M. luteus showed good biofilm formation ability at all tested temperature levels, but S. paucimobilis only displayed limited biofilm formation. Whereas, all these three bacteria well maintained their survival after wet-dry cycles. These results suggest that compared to biofilm formation, ability to survive under hygrodynamics tends to play a more important role in helping bacteria dominate ACUs. Further, this study implies that the absence of odour problem does not guarantee a healthy environment, more attentions should be given to limit the abundance of hydrodynamic-resistant pathogenic bacteria.}, } @article {pmid34635010, year = {2023}, author = {Abdulgader, M and Yu, QJ and Zinatizadeh, AA and Williams, P and Rahimi, Z}, title = {Treatment capacity of a novel flexible fibre biofilm bioreactor treating high-strength milk processing wastewater.}, journal = {Environmental technology}, volume = {44}, number = {7}, pages = {1001-1017}, doi = {10.1080/09593330.2021.1992509}, pmid = {34635010}, issn = {1479-487X}, mesh = {Animals ; *Wastewater ; *Waste Disposal, Fluid ; Milk ; Kinetics ; Bioreactors ; Biofilms ; }, abstract = {This study was focused on the capacity investigation of a novel multistage flexible fibre biofilm reactor (MS-FFBR) to treat milk processing wastewater (MPW) with high organic loading (OLR). The MS-FFBR performance was evaluated at four intermediate stages separately, and also the final effluent quality of the overall system with an influent chemical oxygen demand (CODin) ranged from 1500 ± 20 to 6000 ± 50 mg/L and hydraulic retention times (HRTs) of 8, 12, and 16 h. By comparting the bioreactors into the four stages effectively enhanced the bioreactor's performance. The maximum TCOD removal efficiency was achieved at the first stage, which was about 89 ± 20, 82 ± 20, and 78 ± 20% at HRTs of 16, 12, 8 h, and low CODin of 1600 ± 20, 1590 ± 20, and 1673 ± 20 mg/L, respectively. However, the first stage had less contribution to TCOD removal at high CODin concentrations, reported to be about 42 ± 4%, 46 ± 4%, and 25 ± 4% at CODin of 5960 ± 40, 5830 ± 40, and 5870 ± 40 mg/L, respectively. Furthermore, the MS-FFBR was effective in removing total suspended solids (TSS) and turbidity. The bioreactor has reduced the effluent turbidity to 9.0 ± 0.2, 20.0 ± 0.6, and 16.1 ± 0.5 NTU at low CODin concentrations of 1600 ± 20, 1590 ± 20, and 1670 ± 20 mg/L and HRTs of 16, 12, and 8 h, respectively. The bioreactor revealed a high COD removal rate increased from 2.3 ± 0.1 to 12.2 ± 0.4 kg TCOD/m[3]d by increasing the OLR from 2.4 ± 0.1 to 17.6 ± 0.4 kg TCOD/m[3]d, confirming high reactor capacity for treatment of high-strength wastewater. Kinetic studies confirmed that the biomass yield was low at various HRTs ranging from 0.1 to 0.2 gVSS/gCOD.}, } @article {pmid34633868, year = {2022}, author = {Isom, CM and Fort, B and Anderson, GG}, title = {Evaluating Metabolic Pathways and Biofilm Formation in Stenotrophomonas maltophilia.}, journal = {Journal of bacteriology}, volume = {204}, number = {1}, pages = {e0039821}, pmid = {34633868}, issn = {1098-5530}, support = {R25 GM109432/GM/NIGMS NIH HHS/United States ; 5R25GM109432-06/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acids/metabolism/pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Culture Media ; Gene Expression Regulation, Bacterial/*physiology ; Metabolic Networks and Pathways/*physiology ; Ribose/metabolism/pharmacology ; Stenotrophomonas maltophilia/genetics/*physiology ; }, abstract = {Stenotrophomonas maltophilia has recently arisen as a prominent nosocomial pathogen because of its high antimicrobial resistance and ability to cause chronic respiratory infections. Often the infections are worsened by biofilm formation which enhances antibiotic tolerance. We have previously found that mutation of the gpmA gene, encoding the glycolytic enzyme phosphoglycerate mutase, impacts the formation of this biofilm on biotic and abiotic surfaces at early time points. This finding, indicating an association between carbon source and biofilm formation, led us to hypothesize that metabolism would influence S. maltophilia biofilm formation and planktonic growth. In the present study, we tested the impact of various growth substrates on biofilm levels and growth kinetics to determine metabolic requirements for these processes. We found that S. maltophilia wild type preferred amino acids versus glucose for planktonic and biofilm growth and that gpmA deletion inhibited growth in amino acids. Furthermore, supplementation of the ΔgpmA strain by glucose or ribose phenotypically complemented growth defects. These results suggest that S. maltophilia shuttles amino acid carbon through gluconeogenesis to an undefined metabolic pathway supporting planktonic and biofilm growth. Further evaluation of these metabolic pathways might reveal novel metabolic activities of this pathogen. IMPORTANCE Stenotrophomonas maltophilia is a prominent opportunistic pathogen that often forms biofilms during infection. However, the molecular mechanisms of virulence and biofilm formation are poorly understood. The glycolytic enzyme phosphoglycerate mutase appears to play a role in biofilm formation, and we used a mutant in its gene (gpmA) to probe the metabolic circuitry potentially involved in biofilm development. The results of our study indicate that S. maltophilia displays unique metabolic activities, which could be exploited for inhibiting growth and biofilm formation of this pathogen.}, } @article {pmid34633113, year = {2022}, author = {Guimarães Silva Vasconcelos, P and Medeiros de Almeida Maia, C and Mendes de Vasconcelos, V and Paolla Raimundo E Silva, J and Fechine Tavares, J and Vieira Pereira, J and Wanderley Cavalcanti, Y and Maria Melo de Brito Costa, E}, title = {In vitro inhibition of a multispecies oral cavity biofilm by Syzygium aromaticum essential oil.}, journal = {Gerodontology}, volume = {39}, number = {4}, pages = {366-373}, doi = {10.1111/ger.12594}, pmid = {34633113}, issn = {1741-2358}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Humans ; *Syzygium/chemistry ; *Candidiasis, Oral ; Antifungal Agents/pharmacology ; Candida albicans ; Biofilms ; Candida ; *Oils, Volatile/pharmacology ; }, abstract = {OBJECTIVE: To evaluate the anti-fungal activity of Syzygium aromaticum essential oil and its inhibition of a multispecies biofilm in patients with oral candidiasis.

BACKGROUND: Inhibiting biofilm formation on the denture surface is an important practice for preventing denture stomatitis.

MATERIALS AND METHODS: The anti-fungal activity against Candida albicans and non-albicans Candida species was evaluated through the microdilution method to define Minimal Inhibitory (MIC) and Fungicidal (MFC) Concentrations. Time-kill assay assessed growth kinetics of C. albicans based on pre-determined time points (0, 1, 2, 4, 6 and 24 hours). A multi-species biofilm was formed using human saliva from patients with oral candidiasis and anti-biofilm activity determined by Colony Forming Units per milliliter (CFU/mL) count, fluorescence microscopy with calcofluor white to observe yeast presence and structure, and metabolic activity by XTT (2,3-Bis-(2Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-carboxanilide) reduction assay.

RESULTS: The essential oil showed an anti-fungal activity against all Candida species (MIC 500-1000 µg/mL, MFC 1000-2000 µg/mL), and the time-kill assay showed that 2000 µg/mL (from 2 hours onward) and 1000 µg/mL (from 4 hours onward) concentrations had substantially lower yeast growth than the negative control. In the biofilm analysis, the essential oil had a lower CFU/mL count and a biofilm metabolic activity (91.4%) than seen with its negative control, and in both analyses, the essential oil was not significantly different from the positive control (chlorhexidine). Morphological analysis showed amorphous and fragmented cellular structures after treatment with the essential oil.

CONCLUSION: Syzygium aromaticum essential oil had anti-fungal activities, reduced the Candida growth kinetics substantially and inhibited the multi-species biofilm formation.}, } @article {pmid34630956, year = {2021}, author = {Wijesinghe, GK and de Oliveira, TR and Maia, FC and de Feiria, SB and Barbosa, JP and Joia, F and Boni, GC and Höfling, JF}, title = {Efficacy of true cinnamon (Cinnamomum verum) leaf essential oil as a therapeutic alternative for Candida biofilm infections.}, journal = {Iranian journal of basic medical sciences}, volume = {24}, number = {6}, pages = {787-795}, pmid = {34630956}, issn = {2008-3866}, abstract = {OBJECTIVES: The essential oil (EO) extracted from Cinnamomum verum leaves has been used as an antimicrobial agent for centuries. But its antifungal and antibiofilm efficacy is still not clearly studied. The objective of this research was to evaluate the in vitro antifungal and antibiofilm efficacy of C. verum leaf EO against C. albicans, C. tropicalis, and C. dubliniensis and the toxicity of EO using an in vitro model.

MATERIALS AND METHODS: The effect of EO vapor was evaluated using a microatmosphere technique. CLSI microdilution assay was employed in determining the Minimum Inhibitory (MIC) and Fungicidal Concentrations (MFC). Killing time was determined using a standard protocol. The effect of EO on established biofilms was quantified and visualized using XTT and Scanning Electron Microscopy (SEM), respectively. Post-exposure intracellular changes were visualized using Transmission Electron Microscopy (TEM). The toxicological assessment was carried out with the Human Keratinocyte cell line. The chemical composition of EO was evaluated using Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS: All test strains were susceptible to cinnamon oil vapor. EO exhibited MIC value 1.0 mg/ml and MFC value 2.0 mg/ml against test strains. The killing time of cinnamon oil was 6 hr. Minimum Biofilm Inhibitory Concentration (MBIC50) for established biofilms was <0.2 mg/ml for all test strains. SEM images exhibited cell wall damages, cellular shrinkages, and decreased hyphal formation of Candida. TEM indicated intracellular vacuolation, granulation, and cell wall damages. Cinnamon leaf oil caused no inhibition of HaCaT cells at any concentration tested. Eugenol was the abundant compound in cinnamon oil.

CONCLUSION: C. verum EO is a potential alternative anti-Candida agent with minimal toxicity on the human host.}, } @article {pmid34630951, year = {2021}, author = {Fahmide, F and Ehsani, P and Atyabi, SM}, title = {Time-dependent behavior of the Staphylococcus aureus biofilm following exposure to cold atmospheric pressure plasma.}, journal = {Iranian journal of basic medical sciences}, volume = {24}, number = {6}, pages = {744-751}, pmid = {34630951}, issn = {2008-3866}, abstract = {OBJECTIVES: Formation of Staphylococcus aureus biofilm leads to persistent infection in tissue or on exter-nal and indwelling devices in patients. Cold atmospheric plasma (CAP) is used for eradication of bacterial biofilms and it has diverse applications in the healthcare system. However, there is not sufficient information on the behavior of biofilms during the CAP exposure period.

MATERIALS AND METHODS: Pre-established S. aureus biofilms were exposed to CAP for 0 to 360 sec, then subjected to washing steps and sonication. Subsequently, biomass, number of colonies, vitality of bacteria, structure of colonies, size of produced particles, and viability of bacteria were evaluated by different assays including crystal violet, colony-forming unit, MTT, scanning electron mi-croscopy, confocal laser scanning microscopy, and dynamic light scattering assays.

RESULTS: The results showed that the strength of biomass increased in the first 60 sec, then decreased to less than no-CAP treated controls. Moreover, short CAP exposure (≤60 sec) ehances the fusion of the biofilm extracellular matrix and other components, which results in preservation of bacteria during ultra-sonication and washing steps compared with control biofilms. The S. aureus biofilm structure only breaks down following more CAP exposure (> 90 sec) and demolition. Interestingly, the 60 sec CAP exposure could cause the fusion of biofilm compo-nents, and large particles are detectable.

CONCLUSION: According to this study, an inadequate CAP exposure period prevents absolute eradication of biofilm and enhances the preservation of bacteria in stronger biofilm compartments.}, } @article {pmid34630364, year = {2021}, author = {Sun, B and Luo, H and Jiang, H and Wang, Z and Jia, A}, title = {Inhibition of Quorum Sensing and Biofilm Formation of Esculetin on Aeromonas Hydrophila.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {737626}, pmid = {34630364}, issn = {1664-302X}, abstract = {Quorum sensing (QS) and biofilm formation inhibition activity of esculetin on Aeromonas hydrophila SHAe 115 were evaluated. Exposure to esculetin at 25, 50, and 100μg/ml significantly inhibited the production of protease and hemolysin, the formation of biofilms and attenuated the swarming motility of A. hydrophila SHAe 115. Biofilm forming inhibition was also observed through confocal laser scanning microscopy and scanning electron microscope. Quantitative real-time PCR analysis indicated that genes positively related to QS and biofilm formation were downregulated to varying degrees, while gene (litR) negatively related to biofilm formation was significantly upregulated. The phenotypic results were in good agreement with gene expression levels. These results indicated that esculetin would be a potential QS inhibitor for A. hydrophila.}, } @article {pmid34628997, year = {2021}, author = {Curtin, AM and Thibodeau, MC and Buckley, HL}, title = {Anti-biofouling efficacy of three home and personal care product preservatives: Pseudomonas aeruginosa biofilm inhibition and prevention.}, journal = {Biofouling}, volume = {37}, number = {8}, pages = {879-893}, doi = {10.1080/08927014.2021.1978988}, pmid = {34628997}, issn = {1029-2454}, mesh = {Biofilms ; *Biofouling/prevention & control ; *Cosmetics ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, abstract = {Due to increasing water scarcity, it is essential to determine cost-effective and efficient methods of producing potable water, especially ones that utilize non-traditional sources. Although reverse osmosis (RO) shows promise as a key-player in mitigating water scarcity, it is limited by biofouling. It is therefore integral to identify effective antifoulants that also do not damage the membrane, cause resistance, or negatively impact human health and the environment. Potential antifoulants include preservatives used in home and personal care products. It is hypothesized that safer preservatives can be applied to RO systems to remove or prevent biofouling. Three preservatives including methylisothiazolinone (MIT), phenoxyethanol (PE), and sodium benzoate (SB) were tested via antimicrobial susceptibility tests against P. aeruginosa biofilms grown in 96-well plates to investigate both biofilm prevention and biofilm removal. Data were collected in the form of minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC), respectively. MIT was the most effective of the three preservatives but also poses the highest hazard to human health and the environment. Due to efficacy and safety concerns, MIT, PE, and SB are not the final solution; however, a process was demonstrated for determining the efficacy of novel, safer antifoulants. Ultimately, further investigations into safer antifoulants, paired with a greater understanding of biofilm removal and prevention doses will help make RO a better solution for water scarcity.}, } @article {pmid34628253, year = {2022}, author = {Wang, Z and Chen, X and Zhao, HP}, title = {Model-based analyses of chromate, selenate and sulfate reduction in a methane-based membrane biofilm reactor.}, journal = {Environment international}, volume = {158}, number = {}, pages = {106925}, doi = {10.1016/j.envint.2021.106925}, pmid = {34628253}, issn = {1873-6750}, mesh = {Biofilms ; *Bioreactors ; *Chromates ; Methane ; Oxidation-Reduction ; Selenic Acid ; Sulfates ; }, abstract = {Selenate (SeO4[2-]) and sulfate (SO4[2-]) are frequently present together with chromate (CrO4[2-]) in certain industrial wastewaters. SeO4[2-] and CrO4[2-] are required to be reduced while SO4[2-] reduction should be minimized to avoid the production of toxic sulfide. In this study, a modified biofilm model was employed to investigate the interactions between CrO4[2-], SeO4[2-] and SO4[2-] bioreduction in a methane (CH4)-based membrane biofilm reactor (MBfR). The model was calibrated using steady-state experimental data of two reported CH4-based MBfRs reducing these oxyanions. The modeling results suggested that the majority of methanotrophs (>80%) were located in the outer layer of the biofilm, while the oxyanions-reducing bacteria preferred to grow close to the membrane. The introduction of SeO4[2-] or SO4[2-] enriched selenate/sulfate-reducing bacteria (SeRB/SRB) but decreased the abundance of chromate-reducing bacteria (CRB). A biofilm thickness of >300 μm, an HRT of higher than 4 h and an influent dissolved oxygen concentration of 0.3 mg /L were favorable for simultaneous high-level CrO4[2-] and SeO4[2-] removal. A two-stage MBfR system with optimized operational conditions showed promise in retaining high-purity (>98%) selenium nanoparticles when treating both CrO4[2-] and SeO4[2-] impacted wastewaters. Moreover, the model indicated that efficient CrO4[2-] removal (>90%) along with minor SO4[2-] reduction (<10%) could be realized via maintaining appropriate biofilm thickness (200-250 μm) and influent dissolved oxygen (0.7-0.8 mg /L) in a single MBfR. These findings offer insights for the design and operation of CH4-based technology for remediating CrO4[2-] contaminated industrial wastewaters.}, } @article {pmid34627549, year = {2021}, author = {Riccardi, C and D'Angelo, C and Calvanese, M and Ricciardelli, A and Sellitto, A and Giurato, G and Tutino, ML and Weisz, A and Parrilli, E and Fondi, M}, title = {Whole-genome sequencing of Pseudomonas sp. TAE6080, a strain capable of inhibiting Staphylococcus epidermidis biofilm.}, journal = {Marine genomics}, volume = {60}, number = {}, pages = {100887}, doi = {10.1016/j.margen.2021.100887}, pmid = {34627549}, issn = {1876-7478}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Pseudomonas/genetics ; *Staphylococcus epidermidis/genetics ; Whole Genome Sequencing ; }, abstract = {Antarctic bacteria are able to survive under extreme environmental conditions and have adapted to exploit some of the most ephemeral nutrient pockets. Importantly, such strains have been often shown to be capable of synthesizing compounds of valuable biotechnological importance. Here we show that Pseudomonas sp. TAE6080, a possibly new bacterium isolated in 1994 during water column samplings near the French Antarctic station Dumont d'Urville, is capable of inhibiting the formation of Staphylococcus epidermidis biofilm, known to be an important opportunistic pathogen in infections associated to medical devices. A better understanding of this bacterium can therefore provide useful insight on new bioactive molecules that could play a role against chronic infections. To this end, the anti-biofilm effect of cell-free supernatant of Pseudomonas sp. TAE6080 was evaluated on S. epidermidis RP62A biofilm formation, demonstrating that it significantly reduced its aggregation. Furthermore, genome sequencing, assembly and mining revealed a plethora of putative biosynthetic gene clusters that might be involved in biofilm disruption. The experimental and genomic data presented here open the venue to further investigations on the molecular basis underlying biofilm inhibition.}, } @article {pmid34627321, year = {2021}, author = {Wu, S and Weir, MD and Lei, L and Liu, J and Xu, HHK}, title = {Novel nanographene oxide-calcium phosphate cement inhibits Enterococcus faecalis biofilm and supports dental pulp stem cells.}, journal = {Journal of orthopaedic surgery and research}, volume = {16}, number = {1}, pages = {580}, pmid = {34627321}, issn = {1749-799X}, support = {81870743//National Natural Science Foundation of China/ ; 81800964//National Natural Science Foundation of China/ ; 2021YJ0455//Department of Science and Technology of Sichuan Province/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Bone Cements/pharmacology ; Calcium Phosphates/pharmacology ; *Chitosan/pharmacology ; Dental Pulp ; *Enterococcus faecalis ; Humans ; Oxides ; Stem Cells ; }, abstract = {BACKGROUND: Enterococcus faecalis (E. faecalis) is the most recovered species from the root canals after failed root canal treatment. Calcium phosphate bone cement (CPC) scaffold is promising for applications in endodontic treatment as a kind of root canal sealer. Graphene oxide (GO) has been extensively considered as a kind of promising nano-materials for antibacterial applications. In the present study, an injectable CPC-chitosan paste containing GO was developed for promising endodontic therapy. The antibacterial properties of this paste against E. faecalis biofilms as well as the support for human dental pulp stem cells (hDPSCs) were investigated.

METHODS: CPC-chitosan composite with or without GO injectable scaffold was fabricated. The hDPSC growth and viability on scaffolds were investigated by live/dead assay. Antibacterial effects against E. faecalis biofilms were determined in clinical detin block samples.

RESULTS: The antibacterial CPC-chitosan-GO disks had excellent hDPSC support with the percentages of live cells at around 90%. CPC-chitosan-GO also had greater antibacterial activity on E. faecalis than that of CPC-chitosan control using detin block models (p < 0.05).

CONCLUSIONS: The injectable CPC-chitosan-GO paste had strong effects on inhibition E. faecalis and hDPSC support, which could fill the void of adjusting paste to the defect and shaping in situ for promising endodontic therapy.}, } @article {pmid34626764, year = {2022}, author = {Singh, S and Rinta-Kanto, JM and Lens, PNL and Kokko, M and Rintala, J and O'Flaherty, V and Ijaz, UZ and Collins, G}, title = {Microbial community assembly and dynamics in Granular, Fixed-Biofilm and planktonic microbiomes valorizing Long-Chain fatty acids at 20 °C.}, journal = {Bioresource technology}, volume = {343}, number = {}, pages = {126098}, doi = {10.1016/j.biortech.2021.126098}, pmid = {34626764}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Fatty Acids ; Methane ; *Microbiota ; *Plankton ; Sewage ; }, abstract = {Distinct microbial assemblages evolve in anaerobic digestion (AD) reactors to drive sequential conversions of organics to methane. The spatio-temporal development of three such assemblages (granules, biofilms, planktonic) derived from the same inoculum was studied in replicated bioreactors treating long-chain fatty acids (LCFA)-rich wastewater at 20 °C at hydraulic retention times (HRTs) of 12-72 h. We found granular, biofilm and planktonic assemblages differentiated by diversity, structure, and assembly mechanisms; demonstrating a spatial compartmentalisation of the microbiomes from the initial community reservoir. Our analysis linked abundant Methanosaeta and Syntrophaceae-affiliated taxa (Syntrophus and uncultured) to their putative, active roles in syntrophic LCFA bioconversion. LCFA loading rates (stearate, palmitate), and HRT, were significant drivers shaping microbial community dynamics and assembly. This study of the archaea and syntrophic bacteria actively valorising LCFAs at short HRTs and 20 °C will help uncover the microbiology underpinning anaerobic bioconversions of fats, oil and grease.}, } @article {pmid34626152, year = {2021}, author = {Mevo, SIU and Ashrafudoulla, M and Furkanur Rahaman Mizan, M and Park, SH and Ha, SD}, title = {Promising strategies to control persistent enemies: Some new technologies to combat biofilm in the food industry-A review.}, journal = {Comprehensive reviews in food science and food safety}, volume = {20}, number = {6}, pages = {5938-5964}, doi = {10.1111/1541-4337.12852}, pmid = {34626152}, issn = {1541-4337}, support = {2020R1F1A1067519//National Research Foundation of Korea/ ; }, mesh = {*Biofilms ; Food Handling ; Food Industry ; *Food Microbiology ; Food-Processing Industry ; }, abstract = {Biofilm is an advanced form of protection that allows bacterial cells to withstand adverse environmental conditions. The complex structure of biofilm results from genetic-related mechanisms besides other factors such as bacterial morphology or substratum properties. Inhibition of biofilm formation of harmful bacteria (spoilage and pathogenic bacteria) is a critical task in the food industry because of the enhanced resistance of biofilm bacteria to stress, such as cleaning and disinfection methods traditionally used in food processing plants, and the increased food safety risks threatening consumer health caused by recurrent contamination and rapid deterioration of food by biofilm cells. Therefore, it is urgent to find methods and strategies for effectively combating bacterial biofilm formation and eradicating mature biofilms. Innovative and promising approaches to control bacteria and their biofilms are emerging. These new approaches range from methods based on natural ingredients to the use of nanoparticles. This literature review aims to describe the efficacy of these strategies and provide an overview of recent promising biofilm control technologies in the food processing sector.}, } @article {pmid34624726, year = {2022}, author = {Rivalland, C and Radouani, F and Gonzalez-Rizzo, S and Robert, F and Salvin, P}, title = {Enrichment of Clostridia enhances Geobacter population and electron harvesting in a complex electroactive biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {143}, number = {}, pages = {107954}, doi = {10.1016/j.bioelechem.2021.107954}, pmid = {34624726}, issn = {1878-562X}, mesh = {*Geobacter ; }, abstract = {Current research on microbial fuel cell or microbial electrolysis cell dealt with finding new electroactive bacteria and understanding the mechanisms of electronic exchange. Complex consortia allowed to obtain better performances than pure cultures in part thanks to inter-species cooperation. However, the role of each bacterium in a complex biofilm in the electron harvest on an electrode remains unclear. Thus, we combined electrochemical monitoring of electron exchange and high throughput sequencing analysis in order to describe the bacterial composition and the electroactive performance of mangrove mud biofilms. In this study, secondary electroactive biofilms were formed on carbon electrodes from Desulfuromonas-dominated inoculum of pre-formed bioanodes. The performances and the Desulfuromonas-dominated profile were the same as those of primary bioanodes when the planktonic community was conserved. However, a Clostridium enrichment allowed to restore the performance in maximal current densities promoting an increase of Geobacter population, becoming the most dominant group among the Deltaproteobacteria, replacing Desulfuromonas. These results highlight a positive collaboration between Clostridium and Geobacter spp. helping a bacterial population to achieve with the depletion of their environment. Our study provides new insight into relationships between dominant electroactive bacteria and other bacteria species living in an organic matter-rich environment as mangrove sediments.}, } @article {pmid34624343, year = {2022}, author = {Wang, YC and Wang, C and Han, MF and Tong, Z and Hu, XR and Lin, YT and Zhao, X}, title = {Reduction of biofilm adhesion strength by adjusting the characteristics of biofilms through enzymatic quorum quenching.}, journal = {Chemosphere}, volume = {288}, number = {Pt 1}, pages = {132465}, doi = {10.1016/j.chemosphere.2021.132465}, pmid = {34624343}, issn = {1879-1298}, mesh = {Bacteria ; Biofilms ; *Biofouling/prevention & control ; Bioreactors ; *Quorum Sensing ; }, abstract = {Biofilm adhesion to the surface of a carrier plays an essential role during biofilm formation. Quorum quenching (QQ) has been shown to have great potential for delaying biofouling. However, little is known about whether QQ reduces the adhesion strength of biofilms during the formation process to inhibit biomass accumulation. In this study, we explored the effect of enzymatic QQ on the adhesion strength during biofilm development. In addition, a quantitative method was used to measure the adhesion strength of biofilms based on the shear force of water flow. Experimental results showed that QQ enzyme could reduce the adhesion strength of biofilms by at least 37% compared with the control. Furthermore, the biofilm accumulation rates were 0.05673 and 0.08762 h[-1] with and without the QQ enzyme, illustrating a negative effect of QQ enzyme on biofilm accumulation. Specifically, QQ was confirmed to reduce extracellular polymeric substances, decrease the relative hydrophobicity, change the zeta potential by degrading signal molecules, and weaken the adhesion strength of biofilms. The successful reduction of the adhesion strength of the biofilm through QQ could provide a new strategy for the management and regulation of biofilm adhesion in the bioreactor.}, } @article {pmid34623230, year = {2021}, author = {Moraes, GS and Cachoeira, VS and Alves, FMC and Kiratcz, F and Albach, T and Bueno, MG and Neppelenbroek, KH and Urban, VM}, title = {Is there an optimal method to detach Candida albicans biofilm from dental materials?.}, journal = {Journal of medical microbiology}, volume = {70}, number = {10}, pages = {}, doi = {10.1099/jmm.0.001436}, pmid = {34623230}, issn = {1473-5644}, mesh = {Acrylic Resins/pharmacology ; Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*physiology ; Colony Count, Microbial ; Decontamination/*methods ; *Dental Materials/pharmacology ; Dentures/microbiology ; Humans ; Polymethacrylic Acids/pharmacology ; }, abstract = {Introduction. Candida albicans can produce a complex, dynamic and resistant biofilm on the surface of dental materials, especially denture base acrylic resins and temporary soft liners. This biofilm is the main aetiological factor for denture stomatitis, an oral inflammatory condition characterized by chronic and diffuse erythema and oedema of the denture bearing mucosa.Gap Statement. There is no consensus in the literature regarding the best method to detach biofilms from dental materials. In order to assess the antifungal efficacy of new materials and treatments, the biofilm needs to be properly detached and quantified.Aim. This study compared different methods of detaching C. albicans biofilm from denture base acrylic resin (Vipi Cril) and temporary soft liner (Softone) specimens.Methodology. Specimens of each material were immersed in an inoculum of C. albicans SC5314 and remained for 90 min in orbital agitation at 75 r.p.m. and 37 °C. After the removal of non-adherent cells, the specimens were immersed in RPMI-1640 medium for 48 h. Biofilm formation was evaluated with confocal laser scanning microscopy (n=5). Then, other specimens (n=7) were fabricated, contaminated and immersed in 3 ml of sterile phosphate-buffered saline (PBS) and vortexed or sonicated for 1, 2, 5, or 10 min to detach the biofilm. The quantification of detached biofilm was performed by colony-forming unit (c.f.u.) ml[-1] count. Results were submitted to one-way analysis of variance (ANOVA)/Tukey HSD test (α=0.05).Results. A mature and viable biofilm was observed on the surfaces of both materials. For both materials, there was no significant difference (P>0.05) among detachment methods.Conclusion. Any of the tested methods could be used to detach C. albicans biofilm from hard and soft acrylic materials.}, } @article {pmid34622624, year = {2021}, author = {Li, M and Yan, S and Li, D and Liu, Q}, title = {[Advances on the mechanisms regulating the formation of the biofilm of Listeria monocytogenes].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {37}, number = {9}, pages = {3151-3161}, doi = {10.13345/j.cjb.200734}, pmid = {34622624}, issn = {1872-2075}, mesh = {Biofilms ; Food Contamination ; Food Safety ; *Listeria monocytogenes ; }, abstract = {Listeria monocytogenes is an important food-borne pathogen. The distribution and survival of L. monocytogenes are related to its ability to form biofilms. Biofilms are resistant to adverse environments, and bacteria separated from the biofilms may lead to persistent food contaminations. The formation, maturation and structure of biofilms depend on a variety of external and internal factors, among which a variety of regulatory mechanisms play important roles. This review summarizes the regulatory mechanisms (including intracellular, intercellular and interspecific interactions) involved in the biofilm formation of L. monocytogenes in order to control the biofilm formation in food processing environments, thus providing new intervention strategy for food safety.}, } @article {pmid34622266, year = {2021}, author = {Li, B and Shi, L and Liu, R and Li, Z and Cao, S and Li, J}, title = {A lingering mouthwash with sustained antibiotic release and biofilm eradication for periodontitis.}, journal = {Journal of materials chemistry. B}, volume = {9}, number = {41}, pages = {8694-8707}, doi = {10.1039/d1tb01742j}, pmid = {34622266}, issn = {2050-7518}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Chitosan/chemical synthesis/chemistry/*pharmacology ; Cyclodextrins/chemical synthesis/chemistry/*pharmacology ; Dental Plaque/drug therapy/microbiology/pathology ; Male ; Microbial Sensitivity Tests ; Mouthwashes/chemical synthesis/chemistry/*pharmacology ; Periodontitis/*drug therapy/microbiology/pathology ; Porphyromonas gingivalis/*drug effects ; Rats ; Rats, Sprague-Dawley ; }, abstract = {Dental plaque biofilms are believed to be one of the principal virulence factors in periodontitis resulting in tooth loss. Traditional mouthwashes are limited due to the continuous flow of saliva and poor drug penetration ability in the biofilm. Herein, we fabricated an antibiotic delivery platform based on natural polysaccharides (chitosan and cyclodextrin) as a novel mouthwash for the topical cavity delivery of minocycline. The penetration and residence mechanisms demonstrate that the platform can prolong the residence time up to 12 h on biofilms. Furthermore, sustained release can enhance the penetration of drugs into biofilms. In vitro antibiofilm experimental results indicated that the mouthwash effectively kills bacteria and eradicate biofilms. Effective treatment in vivo was confirmed by the significantly reduced dental plaque and alleviated inflammation observed in a rat periodontitis model. In summary, this novel platform can improve antibiofilm efficiency and prevent drugs from being washed away by saliva, which may provide benefits for many oral infectious diseases.}, } @article {pmid34621728, year = {2021}, author = {Opdensteinen, P and Dietz, SJ and Gengenbach, BB and Buyel, JF}, title = {Expression of Biofilm-Degrading Enzymes in Plants and Automated High-Throughput Activity Screening Using Experimental Bacillus subtilis Biofilms.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {708150}, pmid = {34621728}, issn = {2296-4185}, abstract = {Biofilm-forming bacteria are sources of infections because they are often resistant to antibiotics and chemical removal. Recombinant biofilm-degrading enzymes have the potential to remove biofilms gently, but they can be toxic toward microbial hosts and are therefore difficult to produce in bacteria. Here, we investigated Nicotiana species for the production of such enzymes using the dispersin B-like enzyme Lysobacter gummosus glyco 2 (Lg2) as a model. We first optimized transient Lg2 expression in plant cell packs using different subcellular targeting methods. We found that expression levels were transferable to differentiated plants, facilitating the scale-up of production. Our process yielded 20 mg kg[-1] Lg2 in extracts but 0.3 mg kg[-1] after purification, limited by losses during depth filtration. Next, we established an experimental biofilm assay to screen enzymes for degrading activity using different Bacillus subtilis strains. We then tested complex and chemically defined growth media for reproducible biofilm formation before converting the assay to an automated high-throughput screening format. Finally, we quantified the biofilm-degrading activity of Lg2 in comparison with commercial enzymes against our experimental biofilms, indicating that crude extracts can be screened directly. This ability will allow us to combine high-throughput expression in plant cell packs with automated activity screening.}, } @article {pmid34621691, year = {2021}, author = {Li, D and Zhang, L and Liang, J and Deng, W and Wei, Q and Wang, K}, title = {Biofilm Formation by Pseudomonas aeruginosa in a Novel Septic Arthritis Model.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {724113}, pmid = {34621691}, issn = {2235-2988}, mesh = {Animals ; *Arthritis, Infectious ; Bacterial Proteins/genetics ; Biofilms ; In Situ Hybridization, Fluorescence ; *Pseudomonas aeruginosa/genetics ; Rabbits ; }, abstract = {BACKGROUND: Bacterial biofilms generally contribute to chronic infections and complicate effective treatment outcomes. To date, there have been no reports describing biofilm formation in animal models of septic arthritis caused by Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa is an opportunistic pathogenic bacterium which can lead to septic arthritis. The purpose of this study was to establish a rabbit model of septic arthritis caused by P. aeruginosa to determine whether it leads to biofilm formation in the knee joint cavity. In addition, we explored the role of cyclic di-GMP (c-di-GMP) concentrations in biofilm formation in rabbit models.

METHODS: Twenty rabbits were randomly assigned to five groups: PAO1 (n = 4), PAO1ΔwspF (n = 4), PAO1/plac-yhjH (n = 4) infection group, Luria-Bertani (LB) broth (n = 4), and magnesium tetrasilicate (talc) (n = 4) control groups. Inoculation in the rabbit knee of P. aeruginosa or with the same volume of sterile LB or talc in suspension (control group) was used to induce septic arthritis in the animal model. In the infection groups, septic arthritis was caused by PAO1, PAO1ΔwspF, and PAO1/plac-yhjH strains, respectively. Rabbits were euthanized after 7 days, and pathological examination of synovial membrane was performed. The biofilms on the surface of the synovial membrane were observed by scanning electron microscopy, while the biofilms' fiber deposition was discriminated using peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH).

RESULTS: A rabbit model for knee septic arthritis induced by P. aeruginosa was successfully established. Scanning electron microscopy revealed that PAO1 strains were surrounded in a self-produced extracellular matrix on the surface of synovial membrane and showed biofilm structures. The biofilms in the fibrous deposition were also observed by PNA-FISH. The PNA-FISH assay revealed that the red fluorescence size in the PAO1ΔwspF group was greater than in PAO1 and PAO1/plac-yhjH groups.

CONCLUSIONS: This is the first study to provide evidence that P. aeruginosa forms biofilms in a rabbit model for septic knee arthritis. The rabbit model can be used to investigate new approaches to treatment of biofilms in septic arthritis. Furthermore, c-di-GMP is a key signaling molecule which impacts on biofilm formation in rabbit models of knee septic arthritis.}, } @article {pmid34621249, year = {2021}, author = {Martini, CL and Coronado, AZ and Melo, MCN and Gobbi, CN and Lopez, ÚS and de Mattos, MC and Amorim, TT and Botelho, AMN and Vasconcelos, ATR and Almeida, LGP and Planet, PJ and Zingali, RB and Figueiredo, AMS and Ferreira-Carvalho, BT}, title = {Cellular Growth Arrest and Efflux Pumps Are Associated With Antibiotic Persisters in Streptococcus pyogenes Induced in Biofilm-Like Environments.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {716628}, pmid = {34621249}, issn = {1664-302X}, abstract = {Streptococcus pyogenes (group A Streptococcus-GAS) is an important pathogen for humans. GAS has been associated with severe and invasive diseases. Despite the fact that these bacteria remain universally susceptible to penicillin, therapeutic failures have been reported in some GAS infections. Many hypotheses have been proposed to explain these antibiotic-unresponsive infections; however, none of them have fully elucidated this phenomenon. In this study, we show that GAS strains have the ability to form antimicrobial persisters when inoculated on abiotic surfaces to form a film of bacterial agglomerates (biofilm-like environment). Our data suggest that efflux pumps were possibly involved in this phenomenon. In fact, gene expression assays by real-time qRT-PCR showed upregulation of some genes associated with efflux pumps in persisters arising in the presence of penicillin. Phenotypic reversion assay and whole-genome sequencing indicated that this event was due to non-inherited resistance mechanisms. The persister cells showed downregulation of genes associated with protein biosynthesis and cell growth, as demonstrated by gene expression assays. Moreover, the proteomic analysis revealed that susceptible cells express higher levels of ribosome proteins. It is remarkable that previous studies have reported the recovery of S. pyogenes viable cells from tissue biopsies of patients presented with GAS invasive infections and submitted to therapy with antibiotics. The persistence phenomenon described herein brings new insights into the origin of therapeutic failures in S. pyogenes infections. Multifactorial mechanisms involving protein synthesis inhibition, cell growth impairment and efflux pumps seem to play roles in the formation of antimicrobial persisters in S. pyogenes.}, } @article {pmid34619414, year = {2021}, author = {Vertuan, M and da Silva, JF and Braga, AS and de Souza, BM and Magalhães, AC}, title = {Effect of TiF4/NaF and chitosan solutions on biofilm formation and prevention of dentin demineralization.}, journal = {Archives of oral biology}, volume = {132}, number = {}, pages = {105275}, doi = {10.1016/j.archoralbio.2021.105275}, pmid = {34619414}, issn = {1879-1506}, mesh = {Animals ; *Biofilms ; Cariostatic Agents/pharmacology ; Cattle ; *Chitosan/pharmacology ; *Dental Caries/prevention & control ; Dentin ; Fluorides/pharmacology ; Humans ; Sodium Fluoride/pharmacology ; Titanium ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVE: This study evaluated the effect of experimental solutions containing TiF4/NaF and chitosan on bacterial species of microcosm biofilm and on dentin demineralization.

DESIGN: Microcosm biofilm was produced from human saliva mixed with McBain medium (0.2% sucrose) on bovine dentin for 5 days, under 5% CO2 and 37 °C. From the 2nd day to 5th day, the treatments were applied (1×60s/day) as following: (1) NaF (500 ppm F[-], positive control); (2) TiF4 and NaF (TiF4: 190 ppm Ti[4+] and 300 ppm F[-]; NaF: 190 ppm F[-]); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation). CFU counting was performed for total microorganism, total streptococci, total lactobacilli and mutans streptococci. Dentin demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < 0.05).

RESULTS: No differences were found between the treatments with respect to CFU counting (p > 0.05). Dentin treated with TiF4/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF4/NaF solution, being both able to significantly reduce mineral loss.

CONCLUSION: TiF4/NaF plus chitosan solution, at suitable pH to be clinically applicable, had no antimicrobial effect, but it was able to reduce dentin caries development under this model.}, } @article {pmid34619359, year = {2021}, author = {Bronnec, V and Alexeyev, OA}, title = {In vivo model of Propionibacterium (Cutibacterium) spp. biofilm in Drosophila melanogaster.}, journal = {Anaerobe}, volume = {72}, number = {}, pages = {102450}, doi = {10.1016/j.anaerobe.2021.102450}, pmid = {34619359}, issn = {1095-8274}, mesh = {Animals ; *Biofilms/growth & development ; Drosophila melanogaster/*microbiology ; Fluorescent Antibody Technique ; *Host Microbial Interactions ; Propionibacterium/*physiology/ultrastructure ; }, abstract = {OBJECTIVES: Acne vulgaris is a common inflammatory disorder of the pilosebaceous unit and Propionibacterium acnes biofilm-forming ability is believed to be a contributing factor to the disease development. In vivo models mimicking hair follicle environment are lacking. The aim of this study was to develop an in vivo Propionibacterium spp. biofilm model in Drosophila melanogaster (fruit fly).

METHODS: We created a sterile line of D. melanogaster able to sustain Propionibacterium spp. biofilms in the gut. In order to mimic the lipid-rich, anaerobic environment of the hair follicle, fruit flies were maintained on lipid-rich diet. Propionibacterium spp. biofilms were visualized by immunofluorescence and scanning electron microscopy. We further tested if the biofilm-dispersal activity of DNase I can be demonstrated in the developed model.

RESULTS: We have demonstrated the feasibility of our in vivo model for development and study of P. acnes, P. granulosum and P. avidum biofilms. The model is suitable to evaluate dispersal as well as other agents against P. acnes biofilm.

CONCLUSIONS: We report a novel in vivo model for studying Propionibacterium spp. biofilms. The model can be suitable for both mechanistic as well as interventional studies.}, } @article {pmid34619138, year = {2021}, author = {Amador, CI and Stannius, RO and Røder, HL and Burmølle, M}, title = {High-throughput screening alternative to crystal violet biofilm assay combining fluorescence quantification and imaging.}, journal = {Journal of microbiological methods}, volume = {190}, number = {}, pages = {106343}, doi = {10.1016/j.mimet.2021.106343}, pmid = {34619138}, issn = {1872-8359}, mesh = {Bacteria/*growth & development ; Biofilms/*growth & development ; Fluorescence ; Gentian Violet ; High-Throughput Screening Assays/*methods ; Microbacterium/growth & development ; Optical Imaging/*methods ; Paenibacillus/growth & development ; Pseudomonas putida/growth & development ; Stenotrophomonas/growth & development ; Xanthomonas/growth & development ; }, abstract = {The crystal violet assay is widely used for biofilm quantitation despite its toxicity and variability. Here, we instead combine fluorescence labelling with the Cytation 5 multi-mode plate reader, to enable simultaneous acquisition of both quantitative and imaging biofilm data. This high-throughput method produces more robust data and provides information about morphology and spatial species organization within the biofilm.}, } @article {pmid34618338, year = {2022}, author = {Ranjani, S and Kathun, UR and Hemalatha, S}, title = {Silver Decorated Myconanoparticles Control Growth and Biofilm Formation in Uropathogenic E. coli.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {1}, pages = {504-516}, pmid = {34618338}, issn = {1559-0291}, support = {DST/WOS-B/2018/1583-HFN (G))//department of science and technology, ministry of science and technology/ ; SN042/MI.KU/2020//(aun)/ (seed)/ (jica) sprac/ ; }, mesh = {Biofilms/*drug effects/growth & development ; Nanoparticles/*chemistry ; Penicillium/*chemistry ; *Silver/chemistry/pharmacology ; Uropathogenic Escherichia coli/*physiology ; }, abstract = {Nanotechnology involves the synthesis of nanoparticles that have been used in the therapeutic application for treating diseases. In this present study, we have adopted the synthesis of myconanoparticles from the extracellular extract of endophytic fungi Penicillium sclerotiorum (PsNps) and validated its antibacterial potential against antibiotic-resistant uropathogenic E. coli and ATCC (25,922) strain of Escherichia coli. Endophytic fungi were isolated from the healthy leaves of Tamarindus indica. The genomic DNA from endophytic fungi was isolated and the ITS region was amplified by polymerase chain reaction (PCR) using universal fungal primers ITS1 and ITS4 and sequenced for the identification of endophytic fungal isolates. Penicillium sclerotiorum extract was used for the synthesis of silver nanoparticles (PsNps) and was characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), zeta potential, FE-SEM, and Energy dispersive X-ray analysis (EDAX). Antibacterial activity of PsNps was tested against the antibiotic-resistant uropathogenic E. coli and ATCC (25,922) strain of E. coli. Further experiments were carried out to explore the potential of PsNps in regulating the CTX-M-15 gene. The antimicrobial activity showed that the PsNps inhibited growth, biofilm formation in both the strains of E. coli. The expression of the gene encoding CTX-M-15 was downregulated in a resistant strain of uropathogenic E. coli. Our results suggest that the PsNps could be used as an alternative source for antibiotics. Thus, further studies can be conducted to prove the in vivo potential of PsNps and can be formulated for commercialization.}, } @article {pmid34617410, year = {2021}, author = {Xu, Q and Hua, Y and Zhang, Y and Lv, M and Wang, H and Pi, Y and Xie, J and Wang, C and Yong, Y}, title = {A Biofilm Microenvironment-Activated Single-Atom Iron Nanozyme with NIR-Controllable Nanocatalytic Activities for Synergetic Bacteria-Infected Wound Therapy.}, journal = {Advanced healthcare materials}, volume = {10}, number = {22}, pages = {e2101374}, doi = {10.1002/adhm.202101374}, pmid = {34617410}, issn = {2192-2659}, mesh = {Bacteria ; *Biofilms ; Catalysis ; Combined Modality Therapy ; *Iron ; }, abstract = {Biofilm microenvironment (BME)-activated antimicrobial agents display great potential for improved biofilm-related infection therapy because of their superior specificities and sensitivities, effective eliminations, and minimal side effects. Herein, BME-activated Fe-doped polydiaminopyridine nanofusiform-mediated single-atom nanozyme (FePN SAzyme) is presented for photothermal/chemodynamic synergetic bacteria-infected wound therapy. The photothermal therapy (PTT) function of SAzyme can be specifically initiated by the high level of H2 O2 and further accelerated through mild acid within the inflammatory environment through "two-step rocket launching-like" process. Additionally, the enhanced chemodynamic therapy (CDT) for the FePN SAzyme can also be endowed by producing hydroxyl radicals through reacting with H2 O2 and consuming glutathione (GSH) of the BME, thereby contributing to more efficient synergistic therapeutic effect. Meanwhile, FePN SAzyme could catalyze biofilm-overexpressed H2 O2 decomposing into O2 and overcome the hypoxia of biofilm, which significantly enhances the susceptibility of biofilm and increases the synergistic efficacy. Most importantly, the synergistic therapy of bacterial-induced infection diseases can be switched on by the internal and external stimuli simultaneously, resulting in minimal nonspecific damage to healthy tissue. These remarkable characteristics of FePN SAzyme not only develop an innovative strategy for the BME-activated combination therapy but also open a new avenue to explore other nanozyme-involved nanoplatforms for bacterial biofilm infections.}, } @article {pmid34616691, year = {2021}, author = {Lu, J and Guevara, MA and Francis, JD and Spicer, SK and Moore, RE and Chambers, SA and Craft, KM and Manning, SD and Townsend, SD and Gaddy, JA}, title = {Analysis of Susceptibility to the Antimicrobial and Anti-Biofilm Activity of Human Milk Lactoferrin in Clinical Strains of Streptococcus agalactiae With Diverse Capsular and Sequence Types.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {740872}, pmid = {34616691}, issn = {2235-2988}, support = {T32 HL007411/HL/NHLBI NIH HHS/United States ; T32 AI112541/AI/NIAID NIH HHS/United States ; UL1 RR024975/RR/NCRR NIH HHS/United States ; UL1 TR000445/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Female ; Humans ; Infant, Newborn ; Lactoferrin/pharmacology ; Milk, Human ; Pregnancy ; *Streptococcal Infections ; *Streptococcus agalactiae ; }, abstract = {Group B Streptococcus (GBS) is one of the leading infection-related causes of adverse maternal and neonatal outcomes. This includes chorioamnionitis, which leads to preterm ruptures of membranes and can ultimately result in preterm or stillbirth. Infection can also lead to maternal and neonatal sepsis that may contribute to mortality. Currently, treatment for GBS infection include a bolus of intrapartum antibiotic prophylaxis to mothers testing positive for GBS colonization during late pregnancy. Lactoferrin is an antimicrobial peptide expressed in human breast milk, mucosal epithelia, and secondary granules of neutrophils. We previously demonstrated that lactoferrin possesses antimicrobial and antibiofilm properties against several strains of GBS. This is largely due to the ability of lactoferrin to bind and sequester iron. We expanded upon that study by assessing the effects of purified human breast milk lactoferrin against a panel of phenotypically and genetically diverse isolates of GBS. Of the 25 GBS isolates screened, lactoferrin reduced bacterial growth in 14 and biofilm formation in 21 strains. Stratifying the data, we observed that colonizing strains were more susceptible to the growth inhibition activity of lactoferrin than invasive isolates at lactoferrin concentrations between 250-750 µg/mL. Treatment with 750 µg/mL of lactoferrin resulted in differences in bacterial growth and biofilm formation between discrete sequence types. Differences in bacterial growth were also observed between capsular serotypes 1a and III. Maternally isolated strains were more susceptible to lactoferrin with respect to bacterial growth, but not biofilm formation, compared to neonatal sepsis isolates. Finally, high biofilm forming GBS strains were more impacted by lactoferrin across all isolates tested. Taken together, this study demonstrates that lactoferrin possesses antimicrobial and antibiofilm properties against a wide range of GBS isolates, with maternally isolated colonizing strains being the most susceptible.}, } @article {pmid34614005, year = {2021}, author = {Kim, D and Kim, KY}, title = {Hedera rhombea inhibits the biofilm formation of Candida, thereby increases the susceptibility to antifungal agent, and reduces infection.}, journal = {PloS one}, volume = {16}, number = {10}, pages = {e0258108}, pmid = {34614005}, issn = {1932-6203}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Candida/*drug effects/genetics/pathogenicity ; Candidiasis/*drug therapy/genetics/microbiology ; Drug Resistance, Fungal/drug effects ; Fungal Proteins/genetics ; Gene Expression Regulation, Fungal/drug effects ; Hedera/*chemistry ; Humans ; Hyphae/chemistry ; Microbial Sensitivity Tests ; }, abstract = {Candida is an opportunistic pathogen and a common cause of fungal infections worldwide. Anti-fungal use against Candida infections has resulted in the appearance of resistant strains. The limited choice of anti-fungal therapy means alternative strategies are needed to control fungal infectious diseases. The aim of this study was to evaluate the inhibition of Candida biofilm formation by Hedera rhombea (Korean name: songak) extract. Biofilm formation was assessed using the crystal violet assay which showed a dose dependent reduction in the presence of extract with the biofilm formation inhibitory concentration of C. albicans (IC50 = 12.5μg/ml), C. tropicalis var. tropicalis (IC50 = 25μg/ml), C. parapsilosis var. parapsilosis (IC50 = 6.25μg/ml), C. glabrata (IC50 = 6.25μg/ml), C. tropicalis (IC50 = 12.5μg/ml), and C. parapsilosis (IC50 = 12.5μg/ml) without directly reducing Candida growth. Treatment with 6.25μg/mL of extract increased the antifungal susceptibility to miconazole from 32% decreasing of fungal growth to 98.8% of that based on the fungal growth assay. Treatment of extract dose-dependently reduced the dimorphic transition of Candida based on the dimorphic transition assay and treatment of 3.125μg/mL of extract completely blocked the adherence of Candida to the HaCaT cells. To know the molecular mechanisms of biofilm formation inhibition by extract, qRT-PCR analysis was done, and the extract was found to dose dependently reduce the expression of hyphal-associated genes (ALS3, ECE1, HWP1, PGA50, and PBR1), extracellular matrix genes (GSC1, ZAP1, ADH5, and CSH1), Ras1-cAMP-PKA pathway genes (CYR1, EFG1, and RAS1), Cph2-Tec1 pathway gene (TEC1) and MAP kinases pathway gene (HST7). In this study, Hedera rhombea extract showed inhibition of fungal biofilm formation, activation of antifungal susceptibility, and reduction of infection. These results suggest that fungal biofilm formation is good screen for developing the antifungal adjuvant and Hedera rhombea extract should be a good candidate against biofilm-related fungal infection.}, } @article {pmid34613607, year = {2021}, author = {Park, DW and Park, JH}, title = {Characterization of a novel phage depolymerase specific to Escherichia coli O157:H7 and biofilm control on abiotic surfaces.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {59}, number = {11}, pages = {1002-1009}, pmid = {34613607}, issn = {1976-3794}, mesh = {*Biofilms ; Coliphages/chemistry/*enzymology/genetics ; Escherichia coli O157/physiology/*virology ; Lyases/chemistry/genetics/*metabolism ; Stainless Steel/analysis ; Viral Proteins/chemistry/genetics/metabolism ; }, abstract = {The increasing prevalence of foodborne diseases caused by Escherichia coli O157:H7 as well as its ability to form biofilms poses major threats to public health worldwide. With increasing concerns about the limitations of current disinfectant treatments, phage-derived depolymerases may be used as promising biocontrol agents. Therefore, in this study, the characterization, purification, and application of a novel phage depolymerase, Dpo10, specifically targeting the lipopolysaccharides of E. coli O157, was performed. Dpo10, with a molecular mass of 98 kDa, was predicted to possess pectate lyase activity via genome analysis and considered to act as a receptor-binding protein of the phage. We confirmed that the purified Dpo10 showed O-polysaccharide degrading activity only for the E. coli O157 strains by observing its opaque halo. Dpo10 maintained stable enzymatic activities across a wide range of temperature conditions under 55°C and mild basic pH. Notably, Dpo10 did not inhibit bacterial growth but significantly increased the complement-mediated serum lysis of E. coli O157 by degrading its O-polysaccharides. Moreover, Dpo10 inhibited the biofilm formation against E. coli O157 on abiotic polystyrene by 8-fold and stainless steel by 2.56 log CFU/coupon. This inhibition was visually confirmed via fieldemission scanning electron microscopy. Therefore, the novel depolymerase from E. coli siphophage exhibits specific binding and lytic activities on the lipopolysaccharide of E. coli O157 and may be used as a promising anti-biofilm agent against the E. coli O157:H7 strain.}, } @article {pmid34612670, year = {2021}, author = {Pan, I}, title = {Exploration for Thermostable β-Amylase of a Bacillus sp. Isolated from Compost Soil to Degrade Bacterial Biofilm.}, journal = {Microbiology spectrum}, volume = {9}, number = {2}, pages = {e0064721}, pmid = {34612670}, issn = {2165-0497}, mesh = {Bacillus/*enzymology/isolation & purification ; Bacteria ; *Biofilms/drug effects ; *Composting ; Fermentation ; Hydrogen-Ion Concentration ; Metals/pharmacology ; Pseudomonas aeruginosa/drug effects ; Soil ; *Soil Microbiology ; Staphylococcus aureus/drug effects ; Temperature ; beta-Amylase/genetics/*metabolism/pharmacology ; }, abstract = {In an attempt to explore biofilm degradation using extracellular amylase, a potent amylase-producing bacterium of compost origin, B. subtilis B1U/1, was found to grow suitably in a simple medium of pH 7.5 for 48 h at 37°C under agitation of 140 rpm. This bacillary amylase was recovered by ammonium sulfate precipitation and purified to near homogeneity by membrane filtration and DEAE cellulose column chromatography. The amylase was purified to 4.5-fold with almost 50% yield and 26 kDa of molecular weight. Stable enzyme activity was found in a pH range of 5.2 to 9.0, while 90% residual activity was recorded at 90°C, indicating its thermostable nature. In the presence of 1 mM Fe[++] and Ca[++], the activity of amylase improved; however, it is inhibited by 1 mM Cu[++]. In the presence of 5% NaCl concentration, amylase showed 50% residual activity. The end product analysis identified the enzyme as β-amylase, and a crystal violet assay ensured that it can degrade Pseudomonas aeruginosa (78%) and Staphylococcus aureus biofilm efficiently (75%). The experiments carried out with the compost soil isolate were promising not only for biotechnological exploitation due to its pH flexibility during growth but also for high efficiency in the degradation of biofilms, which makes the organism a potent candidate in the fields of food industries and biomedical engineering, where it can be used as a prosthetic and hip joint cleaner. The β-amylase is highly thermostable since it withstands an elevated temperature for a prolonged period with a minimum loss of activity and is also moderately salt and metal tolerant. IMPORTANCE More than 85% of nosocomial infections are due to the development of bacterial biofilms. Recent research proposed that biofilm-like structures are not only visible in autopsies, biopsies, patients with chronic wounds, and exudates in animal models but are also present in biomedical devices, implants, prosthetic valves, urinary catheters, etc. Because complete eradication of biofilm is highly challenging, alternative methods, such as enzymatic damage of extracellular matrix and mechanical removal, are being implemented due to their easy availability, low cost, and high yield. Organisms from compost piles are rich sources of diverse extracellular enzymes with a high level of stability, which makes them able to withstand the different conditions of their environments. Under diverse environmental conditions, the enzymes are active to continue degradation processes, making them potential candidates in waste management, medicine, and the food and agriculture industries.}, } @article {pmid34610742, year = {2021}, author = {Wang, Y and Zou, Y and Wu, Y and Wei, T and Lu, K and Li, L and Lin, Y and Wu, Y and Huang, C and Zhang, Y and Chen, H and Yu, Q}, title = {Universal Antifouling and Photothermal Antibacterial Surfaces Based on Multifunctional Metal-Phenolic Networks for Prevention of Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {41}, pages = {48403-48413}, doi = {10.1021/acsami.1c14979}, pmid = {34610742}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/radiation effects/*therapeutic use/toxicity ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Biofouling/*prevention & control ; Cell Line ; Coated Materials, Biocompatible/chemistry/radiation effects/*therapeutic use/toxicity ; Copper/chemistry/radiation effects/*therapeutic use/toxicity ; Escherichia coli/drug effects ; Infrared Rays ; Male ; Mice ; Microbial Sensitivity Tests ; Photothermal Therapy ; Polyethylene Glycols/chemistry/toxicity ; Rats, Sprague-Dawley ; Skin/pathology ; Staphylococcal Skin Infections/drug therapy/pathology ; Staphylococcus aureus/drug effects ; Tannins/chemistry/radiation effects/*therapeutic use/toxicity ; }, abstract = {Biofilms formed from the pathogenic bacteria that attach to the surfaces of biomedical devices and implantable materials result in various persistent and chronic bacterial infections, posing serious threats to human health. Compared to the elimination of matured biofilms, prevention of the formation of biofilms is expected to be a more effective way for the treatment of biofilm-associated infections. Herein, we develop a facile method for endowing diverse substrates with long-term antibiofilm property by deposition of a hybrid film composed of tannic acid/Cu ion (TA/Cu) complex and poly(ethylene glycol) (PEG). In this system, the TA/Cu complex acts as a multifunctional building block with three different roles: (i) as a versatile "glue" with universal adherent property for substrate modification, (ii) as a photothermal biocidal agent for bacterial elimination under irradiation of near-infrared (NIR) laser, and (iii) as a potent linker for immobilization of PEG with inherent antifouling property to inhibit adhesion and accumulation of bacteria. The resulted hybrid film shows negligible cytotoxicity and good histocompatibility and could prevent biofilm formation for at least 15 days in vitro and suppress bacterial infection in vivo, showing great potential for practical applications to solve the biofilm-associated problems of biomedical materials and devices.}, } @article {pmid34610107, year = {2021}, author = {Gao, L and Tang, Z and Li, T and Wang, J}, title = {Combination of kaempferol and azithromycin attenuates Staphylococcus aureus-induced osteomyelitis via anti-biofilm effects and by inhibiting the phosphorylation of ERK1/2 and SAPK.}, journal = {Pathogens and disease}, volume = {79}, number = {8}, pages = {}, doi = {10.1093/femspd/ftab048}, pmid = {34610107}, issn = {2049-632X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Azithromycin/*pharmacology ; Biofilms/drug effects ; Cytokines/metabolism ; Disease Management ; Disease Models, Animal ; Disease Susceptibility ; Drug Therapy, Combination ; Kaempferols/*pharmacology ; MAP Kinase Signaling System/*drug effects ; Osteomyelitis/drug therapy/*metabolism/*microbiology ; Phosphorylation/drug effects ; Rats ; Staphylococcal Infections/drug therapy/*metabolism/*microbiology ; Staphylococcus aureus/*drug effects ; Treatment Outcome ; }, abstract = {Osteomyelitis is bacterial infection of bone, commonly caused by Staphylococcus aureus. This work aims to study the potential of azithromycin and kaempferol against chronic osteomyelitis induced by azithromycin-resistant Staphylococcus aureus (ARSA). It was noticed that rats tolerated the treatments with no diarrhoea or weight loss; also, no deaths were observed in rats. The treatment by azithromycin alone failed to inhibit bacterial growth and also had no effect on the infection condition of bone, although the treatment decreased the levels of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α), but did not improve the oxidative stress levels. Kaempferol monotherapy slightly inhibited bacterial growth and bone infection; the treatment also inhibited the levels of IL-6 and (TNF-α). The treatment also improved the antioxidant status. However, the combined treatment of azithromycin and kaempferol significantly suppressed bacterial growth and bone infection and modulated oxidative stress. In vitro, the combined treatment inhibited the levels of IL-6 and TNF-α, and also suppressed the phosphorylation of ERK1/2 and stress-activated protein kinase (SAPK). The combined treatment also showed anti-biofilm activity in ARSA. The combination attenuates ARSA-induced osteomyelitis in rats compared with their treatments alone by reducing oxidative stress, inhibiting the phosphorylation of ERK1/2 and SAPK and inhibiting biofilm formation.}, } @article {pmid34607564, year = {2021}, author = {Yan, J and Li, Y and Guo, X and Wang, X and Liu, F and Li, A and Cao, B}, title = {The effect of ArcA on the growth, motility, biofilm formation, and virulence of Plesiomonas shigelloides.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {266}, pmid = {34607564}, issn = {1471-2180}, mesh = {Bacterial Proteins/*genetics/*metabolism ; *Biofilms ; Plesiomonas/*genetics/*pathogenicity ; Transcription Factors/*genetics/*metabolism ; Virulence/*genetics ; }, abstract = {BACKGROUND: The anoxic redox control binary system plays an important role in the response to oxygen as a signal in the environment. In particular, phosphorylated ArcA, as a global transcription factor, binds to the promoter regions of its target genes to regulate the expression of aerobic and anaerobic metabolism genes. However, the function of ArcA in Plesiomonas shigelloides is unknown.

RESULTS: In the present study, P. shigelloides was used as the research object. The differences in growth, motility, biofilm formation, and virulence between the WT strain and the ΔarcA isogenic deletion mutant strain were compared. The data showed that the absence of arcA not only caused growth retardation of P. shigelloides in the log phase, but also greatly reduced the glucose utilization in M9 medium before the stationary phase. The motility of the ΔarcA mutant strain was either greatly reduced when grown in swim agar, or basically lost when grown in swarm agar. The electrophoretic mobility shift assay results showed that ArcA bound to the promoter regions of the flaK, rpoN, and cheV genes, indicating that ArcA directly regulates the expression of these three motility-related genes in P. shigelloides. Meanwhile, the ability of the ΔarcA strain to infect Caco-2 cells was reduced by 40%; on the contrary, its biofilm formation was enhanced. Furthermore, the complementation of the WT arcA gene from pBAD33-arcA[+] was constructed and all of the above features of the pBAD33-arcA[+] complemented strain were restored to the WT level.

CONCLUSIONS: We showed the effect of ArcA on the growth, motility, biofilm formation, and virulence of Plesiomonas shigelloides, and demonstrated that ArcA functions as a positive regulator controls the motility of P. shigelloides by directly regulating the expression of flaK, rpoN and cheV genes.}, } @article {pmid34607035, year = {2021}, author = {Xu, ZS and Yang, X and Gänzle, MG}, title = {Resistance of biofilm- and pellicle-embedded strains of Escherichia coli encoding the transmissible locus of stress tolerance (tLST) to oxidative sanitation chemicals.}, journal = {International journal of food microbiology}, volume = {359}, number = {}, pages = {109425}, doi = {10.1016/j.ijfoodmicro.2021.109425}, pmid = {34607035}, issn = {1879-3460}, mesh = {Biofilms ; Carnobacterium ; Disinfectants/*pharmacology ; Drug Resistance, Bacterial ; *Escherichia coli/drug effects/genetics ; Oxidative Stress ; *Sanitation ; }, abstract = {Biofilm formation in food processing plants reduces the efficacy of sanitation. The presence of transmissible locus of stress tolerance (tLST) also enhances resistance of planktonic cells of Escherichia coli to sanitation chemicals but the role of tLST in resistance of biofilm-embedded cells remains unclear. This study investigated the link of tLST to biofilm formation and its contribution to resistance of biofilm-embedded E. coli to sanitation. Biofilms were formed as single-strain and as dual-strain biofilms in association with E. coli, Aeromonas australensis or Carnobacterium maltaromaticum. Biofilms on stainless steel were compared to floating biofilms formed at the air-liquid interface (pellicles). The resistance of biofilm-embedded tLST positive strains of E. coli to chlorine, hydrogen peroxide, and peroxyacetic acid was higher than the resistance of tLST negative strains. Higher biofilm density as measured by crystal violet staining was observed in tLST-positive strains of E. coli when compared to tLST negative strains. Biofilm density positively correlated to resistance to disinfectants. The use of confocal laser scanning microscopy detected more compact structure of pellicles compared to solid surface-attached biofilms, resulting in higher chlorine resistance despite the absence of tLST in strains of E. coli. Collectively, the findings of this study elucidated the impact of tLST in strains of E. coli on biofilm formation and sanitizer resistance. These findings may inform the development of improved sanitization protocols for food facilities.}, } @article {pmid34607028, year = {2022}, author = {Qiongjie, W and Yong, Z and Yangyang, Z and Zhouqi, L and Jinxiaoxue, W and Huijuan, C}, title = {Effects of biofilm on metal adsorption behavior and microbial community of microplastics.}, journal = {Journal of hazardous materials}, volume = {424}, number = {Pt A}, pages = {127340}, doi = {10.1016/j.jhazmat.2021.127340}, pmid = {34607028}, issn = {1873-3336}, mesh = {Adsorption ; Biofilms ; *Metals, Heavy ; *Microbiota ; Microplastics ; Plastics ; RNA, Ribosomal, 16S ; *Water Pollutants, Chemical/analysis ; }, abstract = {In this study, the adsorption behavior of Cu(II) and Pb(II) on the biofilm-developed polystyrene (PS) microplastics (MPs) was compared with the virgin PS (V-PS) and UV-aged PS (UV-PS). The results demonstrated that the biofilm could enhance the adsorption abilities onto MPs more than UV radiation. The intra-particle diffusion model suggested that the adsorption on V-PS was dominated by intra-particle diffusion, while the adsorption rate was controlled by the binding diffusion on UV-PS and biofilm-developed PS (Bio-PS). Compared with the V-PS and UV-PS, the Bio-PS showed the largest adsorption capacity based on the Freundlich isotherm model, which indicated that the adsorption of heavy metals onto Bio-PS was multilayer and heterogeneous. The adsorption mechanism of Bio-PS contained physical adsorption, chemisorption, and biosorption. These Bio-PS adsorption types participated in both oxygen and nitrogen groups. Based on the 16S rRNA analysis, the diversity of the microbial community with biofilm changed to a certain extent after the adsorption of heavy metals. Furthermore, the stress of lead (Pb) adsorption had a higher impact on the microbial community distribution and the PS biofilm. This study illustrated how the formation of biofilms can highly affect the adsorption behavior of MPs as well as the microbial community of MPs.}, } @article {pmid34606863, year = {2022}, author = {Zhuang, Z and Yang, G and Zhuang, L}, title = {Exopolysaccharides matrix affects the process of extracellular electron transfer in electroactive biofilm.}, journal = {The Science of the total environment}, volume = {806}, number = {Pt 3}, pages = {150713}, doi = {10.1016/j.scitotenv.2021.150713}, pmid = {34606863}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Electron Transport ; *Electrons ; Extracellular Polymeric Substance Matrix ; }, abstract = {The applications of bioelectrochemical systems (BESs) in the field of environment and energy are achieved through the bioelectrocatalytic process of electroactive biofilms. As a primary component of biofilm, the role of exopolysaccharides in electroactive biofilm in BESs is poorly understood. This study constructed an exopolysaccharides-deficient Geobacter sulfurreducens-based BES to explore the role of exopolysaccharides in electroactive biofilm. Compared with the wild type, the mutant biofilm expressing less exopolysaccharides decreased the capacity of current generation. In the mutant biofilm, the content of exopolysaccharides decreased significantly, resulting in a thinner biofilm and lower cell viability compared with the wild-type biofilm. However, the mutant with overexpressed pili developed a mature biofilm with extended time, which indicating the importance of exopolysaccharides for early biofilm formation and the compensatory role of pili in biofilm formation. The mutant biofilm had less content of c-type cytochromes (c-Cyts) and lower electrochemical activity of extracellular polymeric substances than the wild-type biofilm, suggesting a function of exopolysaccharides anchoring extracellular c-Cyts that essential to extracellular electron transfer (EET) in electroactive biofilms. Our findings demonstrated the essential role of exopolysaccharides in the process of EET in electroactive biofilm, which contributed to a better understanding and optimization of the performance of BESs.}, } @article {pmid34605363, year = {2022}, author = {Sadeghi Mohammadi, S and Vaezi, Z and Naderi-Manesh, H}, title = {Improvement of anti-biofilm activities via co-delivery of curcumin and gentamicin in lipid-polymer hybrid nanoparticle.}, journal = {Journal of biomaterials science. Polymer edition}, volume = {33}, number = {2}, pages = {174-196}, doi = {10.1080/09205063.2021.1982159}, pmid = {34605363}, issn = {1568-5624}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Curcumin/pharmacology ; Gentamicins/pharmacology ; Humans ; Lipids ; Liposomes ; Microbial Sensitivity Tests ; *Nanoparticles ; Persistent Infection ; Polymers ; Pseudomonas aeruginosa ; }, abstract = {Pseudomonas aeruginosa is the most common pathogen that causes chronic lung infections and recurrence of the disease in cystic fibrosis patients by hiding inside cells and biofilm matrix. Herein, we developed gentamicin and curcumin-loaded lipid-polymer hybrid nanoparticle- (termed CG-HNPs) to evaluate in vitro activities against biofilm-embedded P. aeruginosa and compared with lipid nanoparticles containing the same drugs (CG-Lip). The nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), fluorescence spectroscopy, and ultraviolet-visible (UV-vis) spectroscopy, which demonstrated that HNPs with a diameter of approximately 340 nm were uniform. The optimal CG-HNPs formulation illustrated high encapsulation (∼70%) and controlled release characteristics (gradually released in 72 h). The antibacterial activities of generated nanoparticles are maintained against planktonic and biofilm bacteria and it is effective in damage established biofilms. Besides, HNPs were biocompatible and nontoxic to J774 and HFF cell lines and uptake by the macrophages (J774), which facilitated the killing of intracellular bacteria in macrophages. These results introduced CG-HNPs as a promising antibacterial agent for the treatment of chronic infections and intracellular bacteria due to excellent antibacterial activity.}, } @article {pmid34605338, year = {2021}, author = {Cheah, YT and Chan, DJC}, title = {Physiology of microalgal biofilm: a review on prediction of adhesion on substrates.}, journal = {Bioengineered}, volume = {12}, number = {1}, pages = {7577-7599}, pmid = {34605338}, issn = {2165-5987}, mesh = {*Biofilms ; Biomass ; Biotechnology ; *Cell Adhesion ; *Extracellular Polymeric Substance Matrix ; *Microalgae ; Surface Properties ; }, abstract = {In view of high energy cost and water consumption in microalgae cultivation, microalgal-biofilm-based cultivation system has been advocated as a solution toward a more sustainable and resource friendlier system for microalgal biomass production. Algal-derived extracellular polymeric substances (EPS) form cohesive network to interconnect the cells and substrates; however, their interactions within the biofilm are poorly understood. This scenario impedes the biofilm process development toward resource recovery. Herein, this review elucidates on various biofilm cultivation modes and contribution of EPS toward biofilm adhesion. Immobilized microalgae can be envisioned by the colloid interactions in terms of a balance of both dispersive and polar interactions among three interfaces (cells, mediums and substrates). Last portion of this review is dedicated to the future perspectives and challenges on the EPS; with regard to the biopolymers extraction, biopolymers' functional description and cross-referencing between model biofilms and full-scale biofilm systems are evaluated. This review will serve as an informative reference for readers having interest in microalgal biofilm phenomenon by incorporating the three main players in attached cultivation systems: microalgae, EPS and supporting materials. The ability to mass produce these miniature cellular biochemical factories via immobilized biofilm technology will lay the groundwork for a more sustainable and feasible production.}, } @article {pmid34604686, year = {2021}, author = {Syed, A and Zeyad, MT and Shahid, M and Elgorban, AM and Alkhulaifi, MM and Ansari, IA}, title = {Heavy Metals Induced Modulations in Growth, Physiology, Cellular Viability, and Biofilm Formation of an Identified Bacterial Isolate.}, journal = {ACS omega}, volume = {6}, number = {38}, pages = {25076-25088}, pmid = {34604686}, issn = {2470-1343}, abstract = {The release of untreated tannery effluents comprising biotoxic heavy metal (HM) compounds into the ecosystem is one of our society's most serious environmental and health issues. After discharge, HM-containing industrial effluents reach agricultural soils and thus negatively affect the soil microbial diversity. Considering these, we assessed the effect of HMs on identified soil beneficial bacteria. Here, the effects of four heavy metals (HMs), viz., chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb), on cellular growth, physiology, cell permeability, and biofilm formation of Enterobacter cloacae MC9 (accession no.: MT672587) were evaluated. HMs in a concentration range of 25-200 μg mL[-1] were used throughout the study. Among HMs, Cd in general had the maximum detrimental effect on bacterial physiology. With increasing concentrations of HMs, bacterial activities consistently decreased. For instance, 200 μgCr mL[-1] concentration greatly and significantly (p ≤ 0.05) reduced the synthesis of indole-3-acetic acid (IAA) by 70% over control. Furthermore, 200 μg mL[-1] Cd maximally and significantly (p ≤ 0.05) reduced the synthesis of 2,3-dihydroxybenzoic acid (2,3-DHBA), salicylic acid (SA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, and extra polymeric substances (EPSs) of E. cloacae MC9 by 80, 81, 77, and 59%, respectively, over control. While assessing the toxic effect of HMs on the P-solubilizing activity of E. cloacae, the toxicity pattern followed the order Cr (mean value = 94.6 μg mL[-1]) > Cd (mean value = 127.2 μg mL[-1]) > Pb (mean value = 132.4 μg mL[-1]) > Ni (mean value = 140.4 μg mL[-1]). Furthermore, the colony-forming unit (CFU) count (Log10) of strain MC9 was completely inhibited at 150, 175, and 200 μg mL[-1] concentrations of Cr and Cd. The confocal laser scanning microscopic (CLSM) analysis of HM-treated bacterial cells showed an increased number of red-colored dead cells as the concentration of HMs increased from 25 to 200 μg mL[-1]. Likewise, the biofilm formation ability of strain MC9 was maximally (p ≤ 0.05) inhibited at higher concentrations of Cd. In summary, the present investigation undoubtedly suggests that E. cloacae strain MC9 recovered from the HM-contaminated rhizosphere endowed with multiple activities could play an important role in agricultural practices to augment crop productivity in soils contaminated with HMs. Also, there is an urgent need to control the direct discharge of industrial waste into running water to minimize heavy metal pollution. Furthermore, before the application of HMs in agricultural fields, their appropriate field dosages must be carefully monitored.}, } @article {pmid34604306, year = {2021}, author = {Nepravishta, R and Monaco, S and Distefano, M and Rizzo, R and Cescutti, P and Angulo, J}, title = {Multifrequency STD NMR Unveils the Interactions of Antibiotics With Burkholderia multivorans Biofilm Exopolysaccharide.}, journal = {Frontiers in molecular biosciences}, volume = {8}, number = {}, pages = {727980}, pmid = {34604306}, issn = {2296-889X}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; }, abstract = {Biofilms confine bacterial cells within self-produced matrices, offering advantages such as protection from antibiotics and entrapment of nutrients. Polysaccharides are major components in these macromolecular assemblies, and their interactions with other chemicals are of high relevance for the benefits provided by the biofilm 3D molecular matrix. NMR is a powerful technique for the study and characterization of the interactions between molecules of biological relevance. In this study, we have applied multifrequency saturation transfer difference (STD) NMR and DOSY NMR approaches to elucidate the interactions between the exopolysaccharide produced by Burkholderia multivorans C1576 (EpolC1576) and the antibiotics kanamycin and ceftadizime. The NMR strategies presented here allowed for an extensive characterization at an atomic level of the mechanisms behind the implication of the EpolC1576 in the recalcitrance phenomena, which is the ability of bacteria in biofilms to survive in the presence of antibiotics. Our results suggest an active role for EpolC1576 in the recalcitrance mechanisms toward kanamycin and ceftadizime, though through two different mechanisms.}, } @article {pmid34604120, year = {2021}, author = {Holá, V and Opazo-Capurro, A and Scavone, P}, title = {Editorial: The Biofilm Lifestyle of Uropathogens.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {763415}, pmid = {34604120}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Humans ; Life Style ; *Urinary Tract Infections ; }, } @article {pmid34603919, year = {2021}, author = {Al-Joufi, FA and Aljarallah, KM and Hagras, SA and Al Hosiny, IM and Salem-Bekhit, MM and Youssof, AME and Shakeel, F}, title = {Correction to: Microbial spectrum, antibiotic susceptibility profile, and biofilm formation of diabetic foot infections (2014-18): a retrospective multicenter analysis.}, journal = {3 Biotech}, volume = {11}, number = {9}, pages = {419}, doi = {10.1007/s13205-021-02965-8}, pmid = {34603919}, issn = {2190-572X}, abstract = {[This corrects the article DOI: 10.1007/s13205-020-02318-x.].}, } @article {pmid34603306, year = {2021}, author = {Carriquiriborde, F and Martin Aispuro, P and Ambrosis, N and Zurita, E and Bottero, D and Gaillard, ME and Castuma, C and Rudi, E and Lodeiro, A and Hozbor, DF}, title = {Pertussis Vaccine Candidate Based on Outer Membrane Vesicles Derived From Biofilm Culture.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {730434}, pmid = {34603306}, issn = {1664-3224}, mesh = {Animals ; Bacterial Outer Membrane/immunology/*metabolism ; Bacterial Outer Membrane Proteins/genetics/metabolism ; *Biofilms/growth & development ; Bordetella pertussis/genetics/growth & development/immunology/*metabolism ; Disease Models, Animal ; Extracellular Vesicles/immunology/*metabolism ; Female ; Immunization ; Immunogenicity, Vaccine ; Mice, Inbred BALB C ; Pertussis Vaccine/*administration & dosage/immunology/metabolism ; Vaccine Development ; Virulence Factors, Bordetella/genetics/metabolism ; Whooping Cough/immunology/metabolism/microbiology/*prevention & control ; }, abstract = {Outer membrane vesicles (OMV) derived from Bordetella pertussis-the etiologic agent of the resurgent disease called pertussis-are safe and effective in preventing bacterial colonization in the lungs of immunized mice. Vaccine formulations containing those OMV are capable of inducing a mixed Th1/Th2/Th17 profile, but even more interestingly, they may induce a tissue-resident memory immune response. This immune response is recommended for the new generation of pertussis-vaccines that must be developed to overcome the weaknesses of current commercial acellular vaccines (second-generation of pertussis vaccine). The third-generation of pertussis vaccine should also deal with infections caused by bacteria that currently circulate in the population and are phenotypically and genotypically different [in particular those deficient in the expression of pertactin antigen, PRN(-)] from those that circulated in the past. Here we evaluated the protective capacity of OMV derived from bacteria grown in biofilm, since it was observed that, by difference with older culture collection vaccine strains, circulating clinical B. pertussis isolates possess higher capacity for this lifestyle. Therefore, we performed studies with a clinical isolate with good biofilm-forming capacity. Biofilm lifestyle was confirmed by both scanning electron microscopy and proteomics. While scanning electron microscopy revealed typical biofilm structures in these cultures, BipA, fimbria, and other adhesins described as typical of the biofilm lifestyle were overexpressed in the biofilm culture in comparison with planktonic culture. OMV derived from biofilm (OMVbiof) or planktonic lifestyle (OMVplank) were used to formulate vaccines to compare their immunogenicity and protective capacities against infection with PRN(+) or PRN(-) B. pertussis clinical isolates. Using the mouse protection model, we detected that OMVbiof-vaccine was more immunogenic than OMVplank-vaccine in terms of both specific antibody titers and quality, since OMVbiof-vaccine induced antibodies with higher avidity. Moreover, when OMV were administered at suboptimal quantity for protection, OMVbiof-vaccine exhibited a significantly adequate and higher protective capacity against PRN(+) or PRN(-) than OMVplank-vaccine. Our findings indicate that the vaccine based on B. pertussis biofilm-derived OMV induces high protection also against pertactin-deficient strains, with a robust immune response.}, } @article {pmid34601447, year = {2021}, author = {Yu, H and Liu, Y and Yang, F and Xie, Y and Guo, Y and Cheng, Y and Yao, W}, title = {Combined an acoustic pressure simulation of ultrasonic radiation and experimental studies to evaluate control efficacy of high-intensity ultrasound against Staphylococcus aureus biofilm.}, journal = {Ultrasonics sonochemistry}, volume = {79}, number = {}, pages = {105764}, pmid = {34601447}, issn = {1873-2828}, mesh = {Acoustics ; Biofilms ; Glass ; *Staphylococcus aureus ; Ultrasonic Waves ; *Ultrasonics ; }, abstract = {This study evaluated efficacy of high-intensity ultrasound (HIU) on controlling or stimulating Staphylococcus aureus biofilm. Acoustic pressure distribution on the surface of glass slide cultivated S. aureus biofilm was first simulated as a standardized parameter to reflect sono-effect. When the power of HIU was 240 W with acoustic pressure of -1.38×10[5] Pa, a reasonably high clearance rate of S. aureus biofilm was achieved (96.02%). As an all-or-nothing technique, the HIU did not cause sublethal or injury of S. aureus but inactivate the cell directly. A further evaluation of HIU-induced stimulation of biofilm was conducted at a low power level (i.e. 60 W with acoustic pressure of -6.91×10[4] Pa). The low-power-long-duration HIU treatment promoted the formation of S. aureus biofilm and enhanced its resistance as proved by transcriptional changes of genes in S. aureus, including up-regulations of rbf, sigB, lrgA, icaA, icaD, and down-regulation of icaR. These results indicate that the choose of input power is determined during the HIU-based cleaning and processing. Otherwise, the growth of S. aureus and biofilm formation are stimulated when treats by an insufficiently high power of HIU.}, } @article {pmid34601262, year = {2022}, author = {Lv, M and Du, M and Li, Z}, title = {Investigation of mixed species biofilm on corrosion of X65 steel in seawater environment.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {143}, number = {}, pages = {107951}, doi = {10.1016/j.bioelechem.2021.107951}, pmid = {34601262}, issn = {1878-562X}, mesh = {*Steel ; }, abstract = {Microbiologically influenced corrosion (MIC) is a complex process involving the cooperative effect of different bacterial species that coexist in the biofilm. Early studies focused on the MIC of single bacterial communities. However, in natural and industrial fields, biofilms are mostly composed of a variety of species. In this work, the effect of interspecific interaction on corrosion of X65 steel was investigated through the mixed culture of sulfate reducing bacteria (SRB) and iron oxidizing bacteria (IOB). Results demonstrated that the mixed microbial consortia created a cooperative effect to aggravate the local corrosion of X65 steel. Compared with the single species, the presence of IOB increased the growth activity of SRB cells and promoted the role of SRB in steel corrosion. The corrosion form on the surface of X65 steel gradually changed to annular pits induced by anaerobic SRB. The succession of dominant bacteria and the development of mixed species biofilm led to an increase in corrosion rate and local corrosion. The corrosion mechanism of X65 steel by mixed species biofilm at different stages was carefully elucidated.}, } @article {pmid34600674, year = {2021}, author = {Shen, J and Wang, H and Zhu, C and Zhang, M and Shang, F and Xue, T}, title = {Effect of biofilm on the survival of Staphylococcus aureus isolated from raw milk in high temperature and drying environment.}, journal = {Food research international (Ottawa, Ont.)}, volume = {149}, number = {}, pages = {110672}, doi = {10.1016/j.foodres.2021.110672}, pmid = {34600674}, issn = {1873-7145}, mesh = {Animals ; Biofilms ; Humans ; Milk ; *Staphylococcal Infections ; *Staphylococcus aureus/genetics ; Temperature ; }, abstract = {Microbial contamination in dairy products is a momentous factor affecting food safety. Studies have shown that Staphylococcus aureus, which is an important causative agent of a range of infectious and foodborne diseases, may remain in raw milk after a series of complex processing processes. Although most S. aureus possess biofilm formation capacity, there are few studies concerning the role of biofilm formation of this bacterium in stress tolerance and longtime survival in the dairy products. In this study, we selected 5 S. aureus (RMSA1, RMSA2, RMSA3, RMSA4 and RMSA5) isolates from raw milk and investigated their virulence and biofilm characteristics. Results from biofilm assays showed that all 6 S. aureus strains (5 dairy isolates and 1 human-derived model strain NCTC8325) could form complete biofilms in vitro. The reverse transcription-PCR experiments confirmed that multiple genes related to virulence factors and biofilm formation were expressed in the 6 strains. Furthermore, we simulated the high temperature (at 60 °C for 30 min) and drying pressure (at 37 °C for 24 h) during dairy processing to detect the survival rate of strains culturedunderbiofilm or planktonic condition. The data showed that under high temperature and dry conditions, the survival rates of strains cultured under biofilm conditions were much higher than that of strains cultured under planktonic conditions. In addition, the adversity resistance associated with biofilm formation was more obvious in the milk-isolated strains compared with strain NCTC8325. This study provides evidence regarding the mechanisms of stress resistance of S. aureus strains isolated from raw milk and contribute to prevention of dairy product contamination caused by this bacterium.}, } @article {pmid34600386, year = {2022}, author = {Luo, H and Jiang, YZ and Tan, L}, title = {Positively-charged microcrystalline cellulose microparticles: Rapid killing effect on bacteria, trapping behavior and excellent elimination efficiency of biofilm matrix from water environment.}, journal = {Journal of hazardous materials}, volume = {424}, number = {Pt A}, pages = {127299}, doi = {10.1016/j.jhazmat.2021.127299}, pmid = {34600386}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Cellulose ; *Escherichia coli ; Extracellular Polymeric Substance Matrix ; Homicide ; Humans ; *Staphylococcus aureus ; Water ; }, abstract = {Pathogen and biofilm contamination in aqueous systems leave millions of people at risk of waterborne diseases. Herein, to address this issue, a green and highly efficient strategy is developed to concurrently trap and kill bacteria, eliminate the debris and the existing biofilm matrix in water environment via magnetic microparticles. The particles (TPFPs) were prepared from the in-situ deposition of Fe3O4 nanoparticles onto the surface of antibacterial functionalized microcrystalline cellulose (MCC). Noticeably, TPFPs can completely inactivate both S. aureus and E. coli once contacting for 30 min by disrupting the bacterial membrane. Meanwhile, the MCC-based magnetic particles retained 100% biocidal efficiency against E. coli (5 * 10[4]E. coli/mg particles) during ten recycling procedures without any treatment. More importantly, according to the results of trapping behavior and antibiofilm assays, not only bacteria could be captured by the particles (trapping rate was over 85%), but also the residual debris from dead bacteria and fragmented biofilm was together removed based on the special structure and functions of the antibacterial particles (~ 80%), including extremely rough surfaces, surficial positive charge and magneto-responsive property. This study presents an efficient approach for microorganism management in water system which can be expectantly applied to improve the water safety.}, } @article {pmid34598074, year = {2021}, author = {Van Tendeloo, M and Xie, Y and Van Beeck, W and Zhu, W and Lebeer, S and Vlaeminck, SE}, title = {Oxygen control and stressor treatments for complete and long-term suppression of nitrite-oxidizing bacteria in biofilm-based partial nitritation/anammox.}, journal = {Bioresource technology}, volume = {342}, number = {}, pages = {125996}, doi = {10.1016/j.biortech.2021.125996}, pmid = {34598074}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Bacteria ; Biofilms ; Bioreactors ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; Oxygen ; Sewage ; }, abstract = {Mainstream nitrogen removal by partial nitritation/anammox (PN/A) can realize energy and cost savings for sewage treatment. Selective suppression of nitrite oxidizing bacteria (NOB) remains a key bottleneck for PN/A implementation. A rotating biological contactor was studied with an overhead cover and controlled air/N2 inflow to regulate oxygen availability at 20 °C. Biofilm exposure to dissolved oxygen concentrations < 0.51 ± 0.04 mg O2 L[-1] when submerged in the water and < 1.41 ± 0.31 mg O2 L[-1] when emerged in the headspace (estimated), resulted in complete and long-term NOB suppression with a low relative nitrate production ratio of 10 ± 4%. Additionally, weekly biofilm stressor treatments with free ammonia (FA) (29 ± 1 mg NH3-N L[-1] for 3 h) could improve the NOB suppression while free nitrous acid treatments had insufficient effect. This study demonstrated the potential of managing NOB suppression in biofilm-based systems by oxygen control and recurrent FA exposure, opening opportunities for resource efficient nitrogen removal.}, } @article {pmid34597830, year = {2021}, author = {Akhtar, F and Khan, AU}, title = {Antimicrobial photodynamic therapy (aPDT) against vancomycin resistant Staphylococcus aureus (VRSA) biofilm disruption: A putative role of phagocytosis in infection control.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {36}, number = {}, pages = {102552}, doi = {10.1016/j.pdpdt.2021.102552}, pmid = {34597830}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Humans ; Infection Control ; *Methicillin-Resistant Staphylococcus aureus ; Phagocytosis ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Vancomycin-Resistant Staphylococcus aureus ; }, abstract = {Biofilm mediated infections have major clinical impact. Staphylococcus aureus is a pathogen that frequently causes biofilm forming infections, such as those associated with medical devices and persistent wounds. Microorganisms embedded in biofilm are impervious to antibiotics and other antimicrobial agents, thus they are difficult to eliminate. The upsurge of multi-drug resistant strains makes treating such illnesses even more difficult. Therefore, new strategies are required to combat such type of infections. In this work, we have proposed an alternative therapeutic option to eradicate preformed biofilm of vancomycin resistant Staphylococcus aureus (VRSA) and enhanced phagocytosis by neutrophils in fresh human blood using curcumin mediated antimicrobial photodynamic therapy (aPDT).At sub-MIC of curcumin, different anti-biofilm assays and microscopic examinations were performed, followed by 20 J/cm[2] of blue laser light irradiation which corresponds to 52 s only. The result showed significant disruption of VRSA biofilm. Moreover, when curcumin-aPDT treated VRSA biofilm was exposed to whole blood from healthy donors, it was nearly completely eradicated. The present study suggests that curcumin-aPDT enhanced phagocytosis may be a useful strategy for inactivating VRSA biofilms adhering to medical implant surfaces.}, } @article {pmid34597570, year = {2022}, author = {Sun, Z and Xi, J and Yeung, M and Lu, L}, title = {Two quorum sensing enhancement methods optimized the biofilm of biofilters treating gaseous chlorobenzene.}, journal = {The Science of the total environment}, volume = {807}, number = {Pt 1}, pages = {150589}, doi = {10.1016/j.scitotenv.2021.150589}, pmid = {34597570}, issn = {1879-1026}, mesh = {Acyl-Butyrolactones ; Biofilms ; Chlorobenzenes ; *Gases ; *Quorum Sensing ; }, abstract = {In this study, effects of two quorum sensing (QS) enhancement methods on the performance and biofilm of biofilters treating chlorobenzene were investigated. Three biofilters were set up with BF1 as a control, BF2 added exogenous N-acyl-homoserine lactones (AHLs) and BF3 inoculated AHLs-producing bacterium identified as Acinetobacter. The average chlorobenzene elimination capacities were 73 and 77 g/m[3]/h for BF2 and BF3 respectively, which were significantly higher than 50 g/m[3]/h for BF1. The wet biomass of BF2 and BF3 with QS enhancement eventually increased to 60 and 39 kg/m[3] respectively, and it was 29 kg/m[3] for BF1. Analysis on biofilms in three biofilters showed that distribution uniformity, extracellular polymeric substances production, adhesive strengths, viability, and metabolic capacity of biofilms were all prompted by the two QS enhancement methods. Comparisons between the two QS enhancement methods showed that adding exogenous AHLs had more significant enhancing effect on biofilm due to its higher AHLs level in start-up period, while AHLs-producing bacteria had an advantage in enhancing bacterial community diversity. These results demonstrate that QS enhancement methods have the potential to optimize the biofilm and thus improve the performance of biofilters treating recalcitrant VOCs.}, } @article {pmid34594564, year = {2021}, author = {Li, CH and Landis, RF and Makabenta, JM and Nabawy, A and Tronchet, T and Archambault, D and Liu, Y and Huang, R and Golan, M and Cui, W and Mager, J and Gupta, A and Schmidt-Malan, S and Patel, R and Rotello, VM}, title = {Nanotherapeutics using all-natural materials. Effective treatment of wound biofilm infections using crosslinked nanoemulsions.}, journal = {Materials horizons}, volume = {8}, number = {6}, pages = {1776-1782}, pmid = {34594564}, issn = {2051-6355}, support = {R01 AI134770/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; *Bacterial Infections/drug therapy ; Biofilms ; Mice ; *Wound Infection/drug therapy ; }, abstract = {Bacterial wound infections are a threat to public health. Although antibiotics currently provide front-line treatments for bacterial infections, the development of drug resistance coupled with the defenses provided through biofilm formation render these infections difficult, if not impossible, to cure. Antimicrobials from natural resources provide unique antimicrobial mechanisms and are generally recognized as safe and sustainable. Herein, an all-natural antimicrobial platform is reported. It is active against bacterial biofilms and accelerates healing of wound biofilm infections in vivo. This antimicrobial platform uses gelatin stabilized by photocrosslinking using riboflavin (vitamin B2) as a photocatalyst, and carvacrol (the primary constituent of oregano oil) as the active antimicrobial. The engineered nanoemulsions demonstrate broad-spectrum antimicrobial activity towards drug-resistant bacterial biofilms and significantly expedite wound healing in an in vivo murine wound biofilm model. The antimicrobial activity, wound healing promotion, and biosafety of these nanoemulsions provide a readily translatable and sustainable strategy for managing wound infections.}, } @article {pmid34592273, year = {2022}, author = {Hossain, MI and Cheng, L and Cord-Ruwisch, R}, title = {Sustained and enhanced anaerobic removal of COD and nitrogen in a zeolite amended glycogen accumulating organism dominated biofilm process.}, journal = {The Science of the total environment}, volume = {807}, number = {Pt 1}, pages = {150602}, doi = {10.1016/j.scitotenv.2021.150602}, pmid = {34592273}, issn = {1879-1026}, mesh = {Anaerobiosis ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Denitrification ; Glycogen ; Nitrification ; *Nitrogen ; Sewage ; Waste Disposal, Fluid ; Wastewater ; *Zeolites ; }, abstract = {Activated sludge, the most widely used biological wastewater treatment process is known to be expensive to operate, largely due to energy expense for oxygen transfer into the bulk wastewater solution. The alternative of using passive aeration facilitates oxygen supply directly from the air resulting in aeration energy savings. The current study demonstrated sustained and improved removal of chemical oxygen demand (COD) and nitrogen in a zeolite modified glycogen accumulating organisms (GAOs) dominated biofilm reactor, which achieved anaerobic removal of COD and ammonium by the activity of GAOs and zeolite, respectively. Draining of the batch-operated reactor enabled the biofilm to directly uptake oxygen from air (passive aeration) to carry out simultaneous nitrification and denitrification due to the activity of GAO (Candidatus competibacter) and nitrifying bacteria (Nitrosomonas and Nitrospira). Under stable long-term (4-months) operation, the process achieved COD and nitrogen removal at rates of 1354 and 79.1 g m[-3] d[-1], respectively. The biofilm process demonstrated >90% nitrogen removal efficiency in multi-cycle (4/8 cycles) strategy with a short treatment time of 8 h. Due to the passive aeration scheme, the energy consumption of the proposed wastewater treatment process is calculated to be about 13-times less than that of traditional activated sludge process. Therefore, the Passive Aeration Simultaneous Nitrification and Denitrification (PASND) biofilm process is a promising low-energy treatment step for efficient removal of COD and nitrogen from wastewater.}, } @article {pmid34589470, year = {2021}, author = {Hong, Q and Huo, S and Tang, H and Qu, X and Yue, B}, title = {Smart Nanomaterials for Treatment of Biofilm in Orthopedic Implants.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {694635}, pmid = {34589470}, issn = {2296-4185}, abstract = {Biofilms refer to complex bacterial communities that are attached to the surface of animate or inanimate objects, which highly resist the antibiotics or the host immune defense mechanisms. Pathogenic biofilms in medicine are general, chronic, and even costly, especially on medical devices and orthopedic implants. Bacteria within biofilms are the cause of many persistent infections, which are almost impossible to eradicate. Though some progress has been made in comprehending the mechanisms of biofilm formation and persistence, novel alternative compounds or strategies and effective anti-biofilm antibiotics are still lacking. Smart materials of nano size which are able to respond to an external stimulus or internal environment have a great range of applications in clinic. Recently, smart nanomaterials with or without carriage of antibiotics, targeting specific bacteria and biofilm under some stimuli, have shown great potential for pathogenic biofilm and resident bacteria eradication. First, this review briefly summarizes and describes the significance of biofilms and the process of biofilm formation. Then, we focus on some of the latest research studies involving biofilm elimination, which probably could be applied in orthopedic implants. Finally, some outstanding challenges and limitations that need to be settled urgently in order to make smart nanomaterials effectively target and treat implant biofilms are also discussed. It is hoped that there will be more novel anti-biofilm strategies for biofilm infection in the prospective future.}, } @article {pmid34589444, year = {2021}, author = {Wilson, RM and Walker, JM and Yin, K}, title = {Different Concentrations of Lactobacillus acidophilus Cell Free Filtrate Have Differing Anti-Biofilm and Immunomodulatory Effects.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {737392}, pmid = {34589444}, issn = {2235-2988}, support = {R01 AI128202/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; *Lactobacillus acidophilus ; Lipopolysaccharides ; Monocytes ; NF-kappa B ; *Probiotics ; Tumor Necrosis Factor-alpha ; }, abstract = {Probiotics such as various strains of Lactobacillaceae have been shown to have antimicrobial and immunomodulatory activity. In vitro studies have shown that Lactobacilli can decrease bacterial biofilm formation. Effects on immune cells have been unclear with most studies showing anti-inflammatory activity. The mechanism of effects has not been clearly elucidated. In these studies, we used different concentrations of live Lactobacillus acidophilus as well as cell free filtrate (CFF) derived from different concentrations of bacteria. Use of CFF is advantageous as a therapeutic because in vivo it can directly contact immune cells and its concentration is fixed. Both live cells and CFF inhibited Pseudomonas aeruginosa biofilm formation. Importantly, we show that high concentration CFF destroyed mature biofilm. This activity was not due to a lowered pH per se, as pH matched HCl did not remove mature biofilm. High concentration CFF totally inhibited P. aeruginosa growth and was bactericidal (>99.99%), but low concentration CFF was not bactericidal. To examine the immunomodulatory effects of L. acidophilus, we incubated THP-1 monocytes and derived macrophages with CFF and measured TNFα production. CFF did not significantly increase TNFα production in THP-1 monocytes. When cells were prestimulated with LPS, high concentration CFF increased TNFα production even further. In macrophages, high concentration CFF alone increased TNFα production but did not affect LPS prestimulated cells. In contrast, low concentration CFF decreased TNFα production in LPS prestimulated cells. To elucidate the possible mechanisms for these effects, we repeated the experiments using a NF-κB reporter THP-1 cell line. High concentration CFF increased NF-κB activity in monocytes and macrophages. In LPS prestimulated macrophages, only low concentration CFF reduced NF-κB activity. These results suggest that high concentration CFF alone induced NF-κB expression which could account partially for an increase in TNFα production. On the other hand, in macrophages, the lower non-bactericidal concentration of CFF reduced NF-κB expression and decreased TNFα production after LPS prestimulation. Taken together, the results provide evidence that different concentrations of L. acidophilus CFF possess varying bactericidal, anti-biofilm and immunomodulatory effects. This is important in vivo to evaluate the possible use of L. acidophilus CFF in different conditions.}, } @article {pmid34589415, year = {2021}, author = {Abu-Sree, YH and Abdel-Fattah, SM and Abdel-Razek, AG and Badr, AN}, title = {Neoteric approach for peanuts biofilm using the merits of Moringa extracts to control aflatoxin contamination.}, journal = {Toxicology reports}, volume = {8}, number = {}, pages = {1685-1692}, pmid = {34589415}, issn = {2214-7500}, abstract = {Aflatoxigenic fungi and aflatoxins are still a principal challenge that threatened peanut production, marketing, and handling. This study aimed to face the problem using bioactive materials, which reduce fungi and mycotoxin contamination, Moringa extracts may be suitable for solving this challenge. Also, the study was compared the extracts of leaves and oil-free seeds. Fresh leaves and seeds were collected, dried, and milled, while oil was collected by cold pressing. The extracts were evaluated for total phenols, flavonoids, and antioxidants, the oil contents of fatty acids, tocopherol, and sterols were determined. An emulsion for protecting peanuts compositing of leaves extract carried by Moringa oil, and commercial emulsifier. Leaves extract evaluation reflected distinct properties of its fibers, total phenols, and flavonoids. It was recorded a microbial inhibition of bacteria and fungi. The values for both minimal inhibition and fungicidal concentrations were recorded at 3.2 mg/mL and 490 μg/L, respectively. For oil, it showed a unique content, as oleic acid was the main fatty acid, with an affinity between palmitic and behenic in their ratios. Also, oil was recorded by high contents of alpha-tocopherol and Δ7-Campesterol, with 1.166 mg/kg oil as total sterols content. The leaves extract has also a unique capacity to inhibit toxigenic fungi. By applying the composite emulsion for peanut coating, results expressed a high CFU-count inhibition when it was inoculated by A. flavus strain compared to the control.}, } @article {pmid34588455, year = {2021}, author = {Hoffmann, T and Mrusek, D and Bedrunka, P and Burchert, F and Mais, CN and Kearns, DB and Altegoer, F and Bremer, E and Bange, G}, title = {Structural and functional characterization of the bacterial biofilm activator RemA.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {5707}, pmid = {34588455}, issn = {2041-1723}, mesh = {Bacillus subtilis/physiology ; Bacterial Proteins/genetics/isolation & purification/*metabolism/ultrastructure ; Biofilms/*growth & development ; Crystallography, X-Ray ; DNA, Bacterial/*metabolism ; Gene Expression Regulation, Bacterial ; Geobacillus/*physiology ; Models, Genetic ; Mutagenesis, Site-Directed ; Protein Interaction Domains and Motifs/genetics ; Protein Multimerization/genetics ; Recombinant Proteins/genetics/isolation & purification/metabolism/ultrastructure ; Regulatory Sequences, Nucleic Acid ; Transcription Factors/genetics/isolation & purification/*metabolism/ultrastructure ; }, abstract = {Bacillus subtilis can form structurally complex biofilms on solid or liquid surfaces, which requires expression of genes for matrix production. The transcription of these genes is activated by regulatory protein RemA, which binds to poorly conserved, repetitive DNA regions but lacks obvious DNA-binding motifs or domains. Here, we present the structure of the RemA homologue from Geobacillus thermodenitrificans, showing a unique octameric ring with the potential to form a 16-meric superstructure. These results, together with further biochemical and in vivo characterization of B. subtilis RemA, suggests that the protein can wrap DNA around its ring-like structure through a LytTR-related domain.}, } @article {pmid34588437, year = {2021}, author = {Li, C and Hurley, A and Hu, W and Warrick, JW and Lozano, GL and Ayuso, JM and Pan, W and Handelsman, J and Beebe, DJ}, title = {Social motility of biofilm-like microcolonies in a gliding bacterium.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {5700}, pmid = {34588437}, issn = {2041-1723}, support = {R01 CA185251/CA/NCI NIH HHS/United States ; R01 CA186134/CA/NCI NIH HHS/United States ; R01 CA181648/CA/NCI NIH HHS/United States ; R01 EB010039/EB/NIBIB NIH HHS/United States ; }, mesh = {*Biofilms ; Computer Simulation ; Flavobacterium/*physiology ; Intravital Microscopy ; *Locomotion ; Microfluidic Analytical Techniques ; Plant Roots/microbiology ; Soil Microbiology ; Time-Lapse Imaging ; }, abstract = {Bacterial biofilms are aggregates of surface-associated cells embedded in an extracellular polysaccharide (EPS) matrix, and are typically stationary. Studies of bacterial collective movement have largely focused on swarming motility mediated by flagella or pili, in the absence of a biofilm. Here, we describe a unique mode of collective movement by a self-propelled, surface-associated biofilm-like multicellular structure. Flavobacterium johnsoniae cells, which move by gliding motility, self-assemble into spherical microcolonies with EPS cores when observed by an under-oil open microfluidic system. Small microcolonies merge, creating larger ones. Microscopic analysis and computer simulation indicate that microcolonies move by cells at the base of the structure, attached to the surface by one pole of the cell. Biochemical and mutant analyses show that an active process drives microcolony self-assembly and motility, which depend on the bacterial gliding apparatus. We hypothesize that this mode of collective bacterial movement on solid surfaces may play potential roles in biofilm dynamics, bacterial cargo transport, or microbial adaptation. However, whether this collective motility occurs on plant roots or soil particles, the native environment for F. johnsoniae, is unknown.}, } @article {pmid34588414, year = {2021}, author = {Zhang, Q and Ma, Q and Wang, Y and Wu, H and Zou, J}, title = {Molecular mechanisms of inhibiting glucosyltransferases for biofilm formation in Streptococcus mutans.}, journal = {International journal of oral science}, volume = {13}, number = {1}, pages = {30}, pmid = {34588414}, issn = {2049-3169}, mesh = {*Biofilms ; *Dental Caries/microbiology/prevention & control ; Glucosyltransferases/*antagonists & inhibitors ; Humans ; *Streptococcus mutans/enzymology ; }, abstract = {Glucosyltransferases (Gtfs) play critical roles in the etiology and pathogenesis of Streptococcus mutans (S. mutans)- mediated dental caries including early childhood caries. Gtfs enhance the biofilm formation and promotes colonization of cariogenic bacteria by generating biofilm extracellular polysaccharides (EPSs), the key virulence property in the cariogenic process. Therefore, Gtfs have become an appealing target for effective therapeutic interventions that inhibit cariogenic biofilms. Importantly, targeting Gtfs selectively impairs the S. mutans virulence without affecting S. mutans existence or the existence of other species in the oral cavity. Over the past decade, numerous Gtfs inhibitory molecules have been identified, mainly including natural and synthetic compounds and their derivatives, antibodies, and metal ions. These therapeutic agents exert their inhibitory role in inhibiting the expression gtf genes and the activities and secretion of Gtfs enzymes with a wide range of sensitivity and effectiveness. Understanding molecular mechanisms of inhibiting Gtfs will contribute to instructing drug combination strategies, which is more effective for inhibiting Gtfs than one drug or class of drugs. This review highlights our current understanding of Gtfs activities and their potential utility, and discusses challenges and opportunities for future exploration of Gtfs as a therapeutic target.}, } @article {pmid34586634, year = {2021}, author = {Shangguan, W and Xie, T and Zhang, R and Lu, C and Han, X and Zhong, Q}, title = {Anti-biofilm potential of kefir-derived Lactobacillus paracasei L10 against Vibrio parahaemolyticus.}, journal = {Letters in applied microbiology}, volume = {73}, number = {6}, pages = {750-758}, doi = {10.1111/lam.13568}, pmid = {34586634}, issn = {1472-765X}, support = {2020B1212060059//Science and Technology Projects of Guangdong Province/ ; 2021A1515011083//Natural Science Foundation of Guangdong Province/ ; 2017YFC1601203//National Key R&D Program of China/ ; 31972046//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Kefir ; *Lacticaseibacillus paracasei ; *Vibrio parahaemolyticus ; }, abstract = {Vibrio parahaemolyticus, a kind of biofilm-forming foodborne bacterium, presents formidable challenges to the effectiveness of antimicrobial agents. Increasingly, the safety of chemical antimicrobials has aroused the widespread attention of the public. The development of the novel nature antimicrobial agents has become critical for controlling biofilm-related pollution and infections. In this paper, we investigated the antibacterial activity of Lactobacillus paracasei L10, and evaluated the inhibition and eradication effects of the cell-free supernatant (CFS) of the strain on V. parahaemolyticus biofilms in detail. We found that the CFS exhibited marked antibacterial activity against all tested pathogenic bacteria. In co-cultural assay, L. paracasei L10 could notably reduce cell viability in both plankton and biofilm of V. parahaemolyticus and this antagonism effect in biofilm was greater than that in planktonic state. Meanwhile, the growth of V. parahaemolyticus was completely inhibited when 6% (v/v) of the CFS was added, and the supernatant also showed a concentration-dependent manner to inhibit and eradicate the biofilms of V. parahaemolyticus while decreased the metabolic activity of the biofilm in the same way. Moreover, the fluorescence microscopic and confocal laser scanning microscopy images confirmed the anti-biofilm activity of the CFS. This study elucidates that L. paracasei L10 displays a significant anti-biofilm effect on V. parahaemolyticus and the mechanism of its antagonism merits further study, which provides theoretical support for further development and application of L. paracasei L10 as anti-biofilm agents.}, } @article {pmid34586468, year = {2021}, author = {Rana, K and Nayak, SR and Bihary, A and Sahoo, AK and Mohanty, KC and Palo, SK and Sahoo, D and Pati, S and Dash, P}, title = {Association of quorum sensing and biofilm formation with Salmonella virulence: story beyond gathering and cross-talk.}, journal = {Archives of microbiology}, volume = {203}, number = {10}, pages = {5887-5897}, pmid = {34586468}, issn = {1432-072X}, mesh = {Biofilms ; Humans ; *Quorum Sensing ; Salmonella ; *Typhoid Fever ; Virulence ; }, abstract = {Enteric fever (typhoid and paratyphoid fever) is a public health concern which contributes to mortality and morbidity all around the globe. It is caused mainly due to ingestion of contaminated food and water with a gram negative, rod-shaped, flagellated bacterium known as Salmonella enterica serotype typhi (typhoid fever) or paratyphi (paratyphoid fever). Clinical problems associated with Salmonellosis are mainly bacteraemia, gastroenteritis and enteric fever. The bacteria undergo various mechanisms to escape itself from immune reaction of the host, modulating immune response at the site of infection leading to virulence factor production and anti-microbial resistance. Biofilm is one of the adaptation mechanisms through which Salmonella survives in unfavourable conditions and thus is considered as a major threat to public health. Another property of the bacteria is "Quorum Sensing", which is a cell-cell communication and most of the pathogenic bacteria use it to coordinate the production of several virulence factors and other behaviours such as swarming and biofilm formation. Earlier, quorum sensing was believed to be just a medium for communication but, later on, its role in virulence has been studied. However, there are negligible information relating to interaction between quorum sensing and biofilm formation and how these events play crucial role in Salmonella pathogenesis. The review is a summary of updated information regarding how Salmonella uses these properties to spread more and survive better, making a challenge for clinicians and public health experts. Therefore, this review would help bring an insight regarding how biofilm formation and quorum sensing are inter-related and their role in pathogenesis and virulence of Salmonella.}, } @article {pmid34586234, year = {2022}, author = {Fritsch, LN and Dias, ALT and Silva, NC and Fernandes, GJM and Ribeiro, FBAO}, title = {Comparative analysis of biofilm formation by Candida albicans and Candida krusei in different types of contact lenses.}, journal = {Arquivos brasileiros de oftalmologia}, volume = {85}, number = {3}, pages = {235-239}, doi = {10.5935/0004-2749.20220033}, pmid = {34586234}, issn = {1678-2925}, mesh = {Antifungal Agents ; Biofilms ; Candida ; *Candida albicans ; *Contact Lenses, Hydrophilic ; Humans ; Pichia ; }, abstract = {OBJECTIVE: To evaluate the Candida krusei and Candida albicans biofilm formation abilities on 5 different types of contact lenses and compare their metabolic activities and biomass.

METHODS: After biofilm formation by both the test species, their metabolic activity was assessed by the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide reduction assay with menadione, while the biomass was determined by staining with 0.4% crystal violet dye for further statistical analysis.

RESULTS: Both the Candida species could form biofilms on different types of contact lenses, with greater metabolic activities and lower biomass formation in rigid gas permeable lenses.

CONCLUSION: Biofilm formation with greater metabolic activity and greater biomass were expected on soft contact lenses considering their surface hydrophobicity. However, the results demonstrated a greater metabolic activity on rigid contact lenses. This result has a great significance with regards to the increasing risk of microbial keratitis, although further studies are warranted to better elucidate the formation of biofilms on different types of contact lens materials in the future.}, } @article {pmid34585548, year = {2021}, author = {Fayez Hassan, N and Khaled Ibrahim, M and Yousef El Tablawy, S and Abd Allah Farrag, H}, title = {Characterization of Biofilm Producer Nanobacteria Isolated from Kidney Stones of Some Egyptian Patients.}, journal = {Pakistan journal of biological sciences : PJBS}, volume = {24}, number = {9}, pages = {953-970}, doi = {10.3923/pjbs.2021.953.970}, pmid = {34585548}, issn = {1812-5735}, mesh = {Biofilms/*growth & development ; Calcifying Nanoparticles/*analysis/biosynthesis ; Egypt ; Humans ; Kidney Calculi/*microbiology ; }, abstract = {Background and Objective: Nanobacteria (NB) appear to contribute to many calcifying diseases including kidney stones which represent a common problem with inadequate prevention exist. NB framing itself with a mineral coat that assists as a primary defence shield against the immune system, antibiotics. This study aims to collect and detect nanobes from different kidney stones from patients with active urolithiasis then investigated the anti-nano-bacterial activity of some antibiotics alone or in combination with extracts of irradiated herbs of certain medicinal plants which will represent a new approach to therapy for patients with kidney stones. Materials and Methods: Total of 32 nanobes were isolated from 54 kidney stones. Fourier Transforms Infrared Spectroscopy (FTIR) revealed that calcium and phosphate are the main components of stones. Scanning Electron Microscopy (SEM) with Energy-dispersive X-ray spectroscopy (EDX) and Transmission Electron Microscope (TEM), showed that nanobes were Gram-ve cocci with size ranged from (375:600 nm). The biofilm production ability of nanobes was estimated qualitatively and quantitatively. Results: The results revealed that all were strong biofilm producers. Further, the antibiotic susceptibility test indicates their resistance towards most of the tested antibiotics. Molecular identification of the strong biofilm producer isolates by ribosomal ribonucleic acid (rRNA) revealed that it is indicated by 85.37% to Bartonella apis strain PEB0122. Conclusion: The findings of the current study evidenced that combination treatment between Doxycycline (DO) and water extract of khella exhibited a significant reduction in biofilm formation ability of the strongest producers nanobes. Therefore, this treatment can play a role in enhancing public health, especially with patients who suffer from recurrent kidney stone formation.}, } @article {pmid34585267, year = {2022}, author = {Zhang, Y and Chen, Y and Hong, W and Zeng, L and Luo, S}, title = {Invited Response on: "Letter to the Editor: Proper Skin Management in Breast Augmentation with a Periareolar Incision Prevents Implant Contamination and Biofilm-Related Capsular Contracture".}, journal = {Aesthetic plastic surgery}, volume = {46}, number = {Suppl 1}, pages = {11-12}, pmid = {34585267}, issn = {1432-5241}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; *Contracture/surgery ; Humans ; Implant Capsular Contracture/prevention & control/surgery ; *Mammaplasty ; }, } @article {pmid34585132, year = {2021}, author = {Sanawar, H and Kim, LH and Farhat, NM and van Loosdrecht, MCM and Vrouwenvelder, JS}, title = {Periodic chemical cleaning with urea: disintegration of biofilms and reduction of key biofilm-forming bacteria from reverse osmosis membranes.}, journal = {Water research X}, volume = {13}, number = {}, pages = {100117}, pmid = {34585132}, issn = {2589-9147}, abstract = {Biofouling is one of the major factors causing decline in membrane performance in reverse osmosis (RO) plants, and perhaps the biggest hurdle of membrane technology. Chemical cleaning is periodically carried out at RO membrane installations aiming to restore membrane performance. Typical cleaning agents used in the water treatment industry include sodium hydroxide (NaOH) and hydrochloric acid (HCl) in sequence. Rapid biofilm regrowth and related membrane performance decline after conventional chemical cleaning is a routinely observed phenomenon due to the inefficient removal of biomass from membrane modules. Since extracellular polymeric substances (EPS) make up the strongest and predominant structural framework of biofilms, disintegration of the EPS matrix should be the main target for enhanced biomass removal. Previously, we demonstrated at lab-scale the use of concentrated urea as a chemical cleaning agent for RO membrane systems. The protein denaturation property of urea was exploited to solubilize the proteinaceous foulants, weakening the EPS layer, resulting in enhanced biomass solubilization and removal from RO membrane systems. In this work, we investigated the impact of repeated chemical cleaning cycles with urea/HCl as well as NaOH/HCl on biomass removal and the potential adaptation of the biofilm microbial community. Chemical cleaning with urea/HCl was consistently more effective than NaOH/HCl cleaning over 6 cleaning and regrowth cycles. At the end of the 6 cleaning cycles, the percent reduction was 35% and 41% in feed channel pressure drop, 50% and 70% in total organic carbon, 30% and 40% in EPS proteins, and 40% and 66% in the peak intensities of protein-like matter, after NaOH/HCl cleaning and Urea/HCl cleaning, respectively. 16S ribosomal RNA (rRNA) gene sequencing of the biofilm microbial community revealed that urea cleaning does not select for key biofouling families such as Sphingomonadaceae and Xanthomonadaceae that are known to survive conventional chemical cleaning and produce adhesive EPS. This study reaffirmed that urea possesses all the desirable properties of a chemical cleaning agent, i.e., it dissolves the existing fouling layer, delays fresh fouling accumulation by inhibiting the production of a more viscous EPS, does not cause damage to the membranes, is chemically stable, and environmentally friendly as it can be recycled for cleaning.}, } @article {pmid34580787, year = {2021}, author = {Daca, A and Gołębiewska, J and Bronk, M and Jarzembowski, T}, title = {Changes of urine isolates of Escherichia coli and Klebsiella pneumoniae biofilm affect monocytes' response.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {11}, pages = {181}, pmid = {34580787}, issn = {1573-0972}, support = {INKUBATOR INNOWACYJNOŚCI+ MNiSW/2017/DIR/68/II+//European Regional Development Fund under the Intelligent Development Operational Program 2014-2020, Ministry of Science and Higher Education of Poland/ ; }, mesh = {Adolescent ; Adult ; Aged ; Bacterial Adhesion ; *Biofilms ; Escherichia coli/*isolation & purification ; Escherichia coli Infections/diagnosis/microbiology/urine ; Female ; Gram-Negative Bacteria/isolation & purification ; Humans ; Immunosuppression Therapy ; Kidney Diseases/diagnosis/microbiology ; Klebsiella Infections/diagnosis/microbiology/urine ; Klebsiella pneumoniae/*isolation & purification ; Male ; Middle Aged ; *Monocytes ; Urinary Tract Infections/*diagnosis/*microbiology ; Young Adult ; }, abstract = {The Gram negative rods as Escherichia coli and Klebsiella pneumoniae belong to the most common etiology agents of urinary tract infections. The aim of our study was to assess the diversity of biofilm formed in different urinary tract diseases and their impact on monocytes' adherence and activation. The bacteria were obtained from patients with different kidney problems. Some of the patients were after renal transplantation, some of them were not. Changes in the size and granularity of monocytes, as well as their adherence to biofilm, were assessed using FACSVerse flow cytometer after 1 h co-incubation of monocytes and bacterial biofilm in 37 °C. The obtained results were validated against monocytes incubated without bacteria. The isolates from patients with chronic kidney disease formed the most adherent biofilm regardless the presence or absence of inflammatory reaction. Adherence of monocytes also increased during therapy with immunosuppressive agents, but monocytes' response was different when cyclosporine or tacrolimus were used. Additionally the presence of inflammatory reaction in patients with kidney disease modified the monocytes response when the immunosuppressive drugs were used. Considering the obtained results, we conclude that the changes of monocytes' morphology in response to biofilm formed by Gram negative rods could become a tool to detect urinary tract infection, especially in those groups of patients, where the knowledge of ongoing inflammation is important and the standard tools fail to detect it.}, } @article {pmid34579731, year = {2021}, author = {Mann, R and Holmes, A and McNeilly, O and Cavaliere, R and Sotiriou, GA and Rice, SA and Gunawan, C}, title = {Evolution of biofilm-forming pathogenic bacteria in the presence of nanoparticles and antibiotic: adaptation phenomena and cross-resistance.}, journal = {Journal of nanobiotechnology}, volume = {19}, number = {1}, pages = {291}, pmid = {34579731}, issn = {1477-3155}, support = {ARC DP180100474//Australian Research Council Discovery Project/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Metal Nanoparticles/*therapeutic use ; Microbial Sensitivity Tests ; Nanoparticles ; Pseudomonas Infections ; Pseudomonas aeruginosa/drug effects ; Silver ; }, abstract = {BACKGROUND: Treatment of bacterial biofilms are difficult and in many cases, expensive. Bacterial biofilms are naturally more resilient to antimicrobial agents than their free-living planktonic counterparts, rendering the community growth harder to control. The present work described the risks of long-term use of an important alternative antimicrobial, silver nanoparticles (NAg), for the first time, on the dominant mode of bacterial growth.

RESULTS: NAg could inhibit the formation as well as eradicating an already grown biofilm of Pseudomonas aeruginosa, a pathogen notorious for its resilience to antibiotics. The biofilm-forming bacterium however, evolved a reduced sensitivity to the nanoparticle. Evidence suggests that survival is linked to the development of persister cells within the population. A similar adaptation was also seen upon prolonged exposures to ionic silver (Ag[+]). The persister population resumed normal growth after subsequent passage in the absence of silver, highlighting the potential risks of recurrent infections with long-term NAg (and Ag[+]) treatments of biofilm growth. The present study further observed a potential silver/antibiotic cross-resistance, whereby NAg (as well as Ag[+]) could not eradicate an already growing gentamicin-resistant P. aeruginosa biofilm. The phenomena is thought to result from the hindered biofilm penetration of the silver species. In contrast, both silver formulations inhibited biofilm formation of the resistant strain, presenting a promising avenue for the control of biofilm-forming antibiotic-resistant bacteria.

CONCLUSION: The findings signify the importance to study the nanoparticle adaptation phenomena in the biofilm mode of bacterial growth, which are apparently unique to those already reported with the planktonic growth counterparts. This work sets the foundation for future studies in other globally significant bacterial pathogens when present as biofilms. Scientifically based strategies for management of pathogenic growth is necessary, particularly in this era of increasing antibiotic resistance.}, } @article {pmid34578769, year = {2021}, author = {Nobre, CMG and König, B and Pütz, N and Hannig, M}, title = {Hydroxyapatite-Based Solution as Adjunct Treatment for Biofilm Management: An In Situ Study.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {34578769}, issn = {2079-4991}, support = {SFB 1027//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Synthetic hydroxyapatite-based solution is a bioinspired material that may present anti-adhesive properties, restraining the dental biofilm formation without causing adverse effects. This in situ study aims to evaluate the effects of three different hydroxyapatite (HAP) watery solutions as a mouthwash against biofilm adhesion on different dental material surfaces under oral conditions. Hence, four volunteers carried maxillary splints containing enamel, titanium, ceramics, and polymethyl-methacrylate resin (PMMA) samples. Three HAP watery solutions (5%) were prepared with HAP particles presenting different shapes and sizes (HAP I, HAP II, HAP III). During 24 h, the volunteers rinsed two times with one of the following selected tested solution: HAP I, HAP II, HAP III, water, or chlorhexidine 0.2% (CHX). The first rinse was performed 3 min after pellicle formation; the second rinse occurred after a 12 h interval. The surface analysis was performed by scanning electron microscopy (SEM), fluorescence microscopy (FM), and transmission electron microscopy (TEM). Statistical and microscopic analysis showed that most samples treated with any HAP solution revealed reduced biofilm coverage presenting comparable results to CHX treated samples, however without altering the microorganisms' viability. In conclusion, the results of this investigation showed that a pure hydroxyapatite-based mouthrinse could be a promising bioinspired adjunct solution for biofilm management.}, } @article {pmid34578571, year = {2021}, author = {Rojas, B and Soto, N and Villalba, M and Bello-Toledo, H and Meléndrez-Castro, M and Sánchez-Sanhueza, G}, title = {Antibacterial Activity of Copper Nanoparticles (CuNPs) against a Resistant Calcium Hydroxide Multispecies Endodontic Biofilm.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {34578571}, issn = {2079-4991}, support = {11201236//AGENCIA NACIONAL DE INVESTIGACION Y DESARROLLO ANID FONDECYT IN 2020/ ; }, abstract = {Endodontic treatment reduces the amount of bacteria by using antimicrobial agents to favor healing. However, disinfecting all of the canal system is difficult due to its anatomical complexity and may result in endodontic failure. Copper nanoparticles have antimicrobial activity against diverse microorganisms, especially to resistant strains, and offer a potential alternative for disinfection during endodontic therapy. This study evaluated the antibacterial action of copper nanoparticles (CuNPs) on an ex vivo multispecies biofilm using plaque count compared to the antibacterial activity of calcium hydroxide Ca(OH)2. There were significant differences between the Ca(OH)2 and CuNPs groups as an intracanal dressing compared with the CuNPs groups as an irrigation solution (p < 0.0001). An increase in the count of the group exposed to 7 days of Ca(OH)2 was observed compared to the group exposed to Ca(OH)2 for 1 day. These findings differ from what was observed with CuNPs in the same period of time. Antibacterial activity of CuNPs was observed on a multispecies biofilm, detecting an immediate action and over-time effect, gradually reaching their highest efficacy on day 7 after application. The latter raises the possibility of the emergence of Ca(OH)2-resistant strains and supports the use of CuNPs as alternative intracanal medication.}, } @article {pmid34578244, year = {2021}, author = {Pieranski, MK and Rychlowski, M and Grinholc, M}, title = {Optimization of Streptococcus agalactiae Biofilm Culture in a Continuous Flow System for Photoinactivation Studies.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34578244}, issn = {2076-0817}, support = {2016/23/B/NZ7/03236//Narodowe Centrum Nauki/ ; }, abstract = {Streptococcus agalactiae is a relevant cause of neonatal mortality. It can be transferred to infants via the vaginal tract and cause meningitis, pneumonia, arthritis, or sepsis, among other diseases. The cause of therapy ineffectiveness and infection recurrence is the growth of bacteria as biofilms. To date, several research teams have attempted to find a suitable medium for the cultivation of S. agalactiae biofilms. Among others, simulated vaginal fluid has been used; however, biofilm production in this medium has been found to be lower than that in tryptic soy broth. We have previously shown that S. agalactiae can be successfully eradicated by photoinactivation in planktonic culture, but there have been no studies on biofilms. The aim of this study was to optimize S. agalactiae biofilm culture conditions to be used in photoinactivation studies. We compared biofilm production by four strains representing the most common serotypes in four different broth media with crystal violet staining. Then, we evaluated stationary biofilm culture in microtiter plates and biofilm growth in a CDC Biofilm Reactor[®] (BioSurface Technologies, Bozeman, MT, USA) under continuous flow conditions. Subsequently, we applied Rose Bengal-mediated photoinactivation to both biofilm models. We have shown that photoinactivation is efficient in biofilm eradication and is not cyto/phototoxic to human keratinocytes. We found conditions allowing for stable and repetitive S. agalactiae biofilm growth in continuous flow conditions, which can be successfully utilized in photoinactivation assays and potentially in all other antibacterial studies.}, } @article {pmid34577132, year = {2021}, author = {Elnagdy, S and Raptopoulos, M and Kormas, I and Pedercini, A and Wolff, LF}, title = {Local Oral Delivery Agents with Anti-Biofilm Properties for the Treatment of Periodontitis and Peri-Implantitis. A Narrative Review.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {18}, pages = {}, pmid = {34577132}, issn = {1420-3049}, support = {Non applicable//This study was supported by a Division of Periodontal Research Grant (Wolff, L)/ ; }, mesh = {Biofilms ; Humans ; Peri-Implantitis ; *Periodontitis ; }, abstract = {Despite many discoveries over the past 20 years regarding the etiopathogenesis of periodontal and peri-implant diseases, as well as significant advances in our understanding of microbial biofilms, the incidence of these pathologies continues to rise. For this reason, it was clear that other strategies were needed to eliminate biofilms. In this review, the literature database was searched for studies on locally delivered synthetic agents that exhibit anti-biofilm properties and their potential use in the treatment of two important oral diseases: periodontitis and peri-implantitis.}, } @article {pmid34576888, year = {2021}, author = {Gomes, LC and Mergulhão, FJM}, title = {A Selection of Platforms to Evaluate Surface Adhesion and Biofilm Formation in Controlled Hydrodynamic Conditions.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576888}, issn = {2076-2607}, support = {PTDC/CTM-COM/4844/2020//Fundação para a Ciência e a Tecnologia/ ; Base Funding - UIDB/ 00511/2020 of the Laboratory for Process Engineering, Environment, Bio-technology and Energy - LEPABE//FCT/MCTES (PID-DAC)/ ; HealthyWaters (NORTE-01-0145- FEDER-000069) and 2SMART (NORTE-01-0145- FEDER-000054)//Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)/ ; CEECIND/01700/2017//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {The early colonization of surfaces and subsequent biofilm development have severe impacts in environmental, industrial, and biomedical settings since they entail high costs and health risks. To develop more effective biofilm control strategies, there is a need to obtain laboratory biofilms that resemble those found in natural or man-made settings. Since microbial adhesion and biofilm formation are strongly affected by hydrodynamics, the knowledge of flow characteristics in different marine, food processing, and medical device locations is essential. Once the hydrodynamic conditions are known, platforms for cell adhesion and biofilm formation should be selected and operated, in order to obtain reproducible biofilms that mimic those found in target scenarios. This review focuses on the most widely used platforms that enable the study of initial microbial adhesion and biofilm formation under controlled hydrodynamic conditions-modified Robbins devices, flow chambers, rotating biofilm devices, microplates, and microfluidic devices-and where numerical simulations have been used to define relevant flow characteristics, namely the shear stress and shear rate.}, } @article {pmid34576863, year = {2021}, author = {Shrivastava, D and Natoli, V and Srivastava, KC and Alzoubi, IA and Nagy, AI and Hamza, MO and Al-Johani, K and Alam, MK and Khurshid, Z}, title = {Novel Approach to Dental Biofilm Management through Guided Biofilm Therapy (GBT): A Review.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576863}, issn = {2076-2607}, abstract = {Dental biofilm plays a very crucial role in the etiopathogenesis of periodontal andperi-implant diseases. Over the past decade, tremendous research has been carried outto know the structure of biofilm and the mechanism by which it causes the destruction of supporting tissues of tooth or implant. Periodontal or peri-implant therapy usually begins with primarily removing thebiofilm and is considered as non-surgical mechanical debridement. Although scaling and root planing (SRP) is regarded as a gold standard for mechanical plaque debridement, various other means of biofilm removal have constantly been evolving. These may vary from different scaling systems such as vector systems to decontamination of pockets with LASER therapy. Nowadays, a new concept has emerged known as "guided biofilm therapy" (GBT). It is beneficial in removing the biofilm around the tooth and implant structures, resulting in better or comparable clinical outcomes than SRP. These results were substantiated with the reduction in the microbial load as well as the reduction in the inflammatory cytokines. This review will highlight the various aspects of GBT used in periodontal and peri-implant disease.}, } @article {pmid34576818, year = {2021}, author = {Meza-Torres, J and Auria, E and Dupuy, B and Tremblay, YDN}, title = {Wolf in Sheep's Clothing: Clostridioides difficile Biofilm as a Reservoir for Recurrent Infections.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576818}, issn = {2076-2607}, abstract = {The microbiota inhabiting the intestinal tract provide several critical functions to its host. Microorganisms found at the mucosal layer form organized three-dimensional structures which are considered to be biofilms. Their development and functions are influenced by host factors, host-microbe interactions, and microbe-microbe interactions. These structures can dictate the health of their host by strengthening the natural defenses of the gut epithelium or cause disease by exacerbating underlying conditions. Biofilm communities can also block the establishment of pathogens and prevent infectious diseases. Although these biofilms are important for colonization resistance, new data provide evidence that gut biofilms can act as a reservoir for pathogens such as Clostridioides difficile. In this review, we will look at the biofilms of the intestinal tract, their contribution to health and disease, and the factors influencing their formation. We will then focus on the factors contributing to biofilm formation in C. difficile, how these biofilms are formed, and their properties. In the last section, we will look at how the gut microbiota and the gut biofilm influence C. difficile biofilm formation, persistence, and transmission.}, } @article {pmid34576809, year = {2021}, author = {Ackermann, K and Kenngott, R and Settles, M and Gerhards, H and Maierl, J and Wollanke, B}, title = {In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576809}, issn = {2076-2607}, abstract = {Equine recurrent uveitis (ERU) causes painful inflammatory attacks and oftentimes blindness in the affected eyes. The disease is considered a late sequela of systemic leptospirosis. The most effective therapy is the surgical removal of the vitreous (vitrectomy), which is not only therapeutic, but provides vitreous material that can be assessed diagnostically. For example, the lipL32 gene, culturable Leptospira spp., and anti-Leptospira antibodies have all been detected in vitreous samples obtained from eyes with chronic ERU. Despite this clear evidence of leptospiral involvement, the systemic administration of antibiotics in infected horses is ineffective at resolving ERU. This syndrome of chronic recurrent inflammation, which is unresponsive to antibiotic therapy, combined with apparent bacteria evading the immune response, is consistent with a biofilm-associated infection. The purpose of this study, therefore, was to detect the in vivo biofilm formation of Leptospira spp. in vitreous samples collected during vitrectomy and examined using a Warthin-Starry silver stain and immunohistochemistry. All known steps of biofilm formation were visualized in these samples, including individual Leptospira spp., leptospiral microcolonies and dense roundish accumulations of Leptospira spp. In many instances spirochetes were surrounded by an extracellular substance. Taken together, data from the present study show that ERU is a biofilm-associated intraocular leptospiral infection, which best explains the typical clinical course.}, } @article {pmid34576751, year = {2021}, author = {Plota, M and Sazakli, E and Giormezis, N and Gkartziou, F and Kolonitsiou, F and Leotsinidis, M and Antimisiaris, SG and Spiliopoulou, I}, title = {In Vitro Anti-Biofilm Activity of Bacteriophage K (ATCC 19685-B1) and Daptomycin against Staphylococci.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576751}, issn = {2076-2607}, support = {39540000//University of Patras/ ; MIS 5049223//European Social Fund-ESF/ ; }, abstract = {The purpose of the present study was to investigate anti-staphylococcal activity of daptomycin and bacteriophage K, alone or in combination, against biofilm-producers and non-producers S. aureus and S. epidermidis strains, under biofilm forming and cells' proliferation conditions. Daptomycin and bacteriophage K (ATCC 19685B1), in different concentrations, were tested against 10 Staphylococcus aureus and 10 S. epidermidis, characterized by phenotypes and genotypes. The quantitative microtiter plate (crystal violet, CV), methylthiazoltetrazolium (MTT), and growth curve (GC) assays were performed. No statistically significant difference was found between species, whereas daptomycin alone performed better using medium and high concentrations of the drug and bacteriophage K was more active against strains with higher susceptibility, by CV and MTT assays. Best results were achieved using both agents combined in high concentrations. Bacteriophage K was effective within 3.8 and 2.4 h, depending on the concentration used, by the GC assay. Combination of daptomycin with bacteriophage K was more effective against staphylococci, depending on the concentrations used and strains' susceptibility. Further studies are needed to evaluate if this approach might be a choice for prevention or therapy of biofilm-associated infections.}, } @article {pmid34576742, year = {2021}, author = {Kaya, E and Batoni, G and Di Luca, M and Apolloni, E and Mazzoni, A and Maisetta, G and Esin, S}, title = {Planktonic and Biofilm-Associated Pseudomonas aeruginosa and Staphylococcus epidermidis Elicit Differential Human Peripheral Blood Cell Responses.}, journal = {Microorganisms}, volume = {9}, number = {9}, pages = {}, pmid = {34576742}, issn = {2076-2607}, support = {Fondi di Ateneo//Università di Pisa/ ; PhD Programme Clinical and Translational Science//Università di Pisa/ ; }, abstract = {Despite the considerable progress made in recent years, our understanding of the human immune response to microbial biofilms is still poor. The aim of the present study was to compare the in vitro response of human peripheral blood mononuclear cells (PBMC) to biofilms and planktonic cells of Pseudomonas aeruginosa and Staphylococcus epidermidis, two bacterial species particularly relevant in patients with cystic fibrosis or undergoing endovascular catheterization, respectively. PBMC isolated from healthy donors were co-cultured with 24 h-old biofilms or with exponentially growing cells of both species. Following 24 h of co-culture, the expression of early activation markers and the levels of cytokines in the culture supernatants were assessed by flow cytometry, while biofilm biomass and architecture were evaluated by crystal violet staining, CFU count, and confocal microscopy. Around 20% of PBMC was activated in response to both biofilms and planktonic cells of P. aeruginosa. In contrast, planktonic cells of S. epidermidis induced a statistically higher degree of activation than their biofilm counterpart (25% versus 15%; p < 0.01). P. aeruginosa biofilms stimulated pro-inflammatory (TNF-α, IL-1β, IFN-γ, and IL-6) and anti-inflammatory (IL-10) cytokine production at statistically significant levels higher than its planktonic counterpart, while an opposite trend was observed with S. epidermidis. Differences in the architecture of the biofilms and in the number of PBMC infiltrating the biofilms between the two bacterial species may at least partially explain these findings. Collectively, the results obtained highlighted marked differences in the host-cell response depending on the species and the mode of growth (biofilms versus planktonic cultures), allowing speculations on the different strategies adopted by P. aeruginosa and S. epidermidis to persist in the host during the course of chronic infections.}, } @article {pmid34576276, year = {2021}, author = {Jabłońska-Wawrzycka, A and Rogala, P and Czerwonka, G and Gałczyńska, K and Drabik, M and Dańczuk, M}, title = {Ruthenium Complexes with 2-Pyridin-2-yl-1H-benzimidazole as Potential Antimicrobial Agents: Correlation between Chemical Properties and Anti-Biofilm Effects.}, journal = {International journal of molecular sciences}, volume = {22}, number = {18}, pages = {}, pmid = {34576276}, issn = {1422-0067}, support = {Project miniGrant UJK No. SUPB.RN .21.171//Polish Ministry of Science and Higher Education/ ; }, mesh = {Anti-Infective Agents/*pharmacology ; Benzimidazoles/*chemistry/metabolism/pharmacology ; Biofilms/*drug effects ; Cell Line ; Cell Survival ; Coordination Complexes/chemistry ; *Drug Design ; Drug Evaluation, Preclinical ; Electrochemistry/methods ; Escherichia coli/drug effects ; Humans ; Hydrogen-Ion Concentration ; Kinetics ; Ligands ; Microbial Sensitivity Tests ; Oxygen/chemistry ; Pseudomonas aeruginosa/drug effects ; Pyridines/metabolism/*pharmacology ; Ruthenium/*chemistry ; Staphylococcus aureus/drug effects ; Surface Properties ; }, abstract = {Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2'-PyBIm): [(η[6]-p-cymene)Ru[II]ClL1]PF6 (Ru(II) complex), mer-[Ru[III]Cl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[Ru[III]Cl4(CH3CN)2]2[Ru[IV]Cl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.}, } @article {pmid34574207, year = {2021}, author = {Avila-Novoa, MG and Navarrete-Sahagún, V and González-Gómez, JP and Novoa-Valdovinos, C and Guerrero-Medina, PJ and García-Frutos, R and Martínez-Chávez, L and Martínez-Gonzáles, NE and Gutiérrez-Lomelí, M}, title = {Conditions of In Vitro Biofilm Formation by Serogroups of Listeria monocytogenes Isolated from Hass Avocados Sold at Markets in Mexico.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34574207}, issn = {2304-8158}, abstract = {Listeria monocytogenes is an important pathogen that has been implicated in foodborne illnesses and the recall of products such as fruit and vegetables. This study determines the prevalence of virulence-associated genes and serogroups and evaluates the effects of different growth media and environmental conditions on biofilm formation by L. monocytogenes. Eighteen L. monocytogenes isolates from Hass avocados sold at markets in Guadalajara, Mexico, were characterized by virulence-associated genes and serogroup detection with PCR. All isolates harbored 88.8% actA, 88.8% plcA, 83.3% mpl, 77.7% inlB, 77.7% hly, 66.6% prfA, 55.5% plcB, and 33.3% inlA. The results showed that 38.8% of isolates harbored virulence genes belonging to Listeria pathogenicity island 1 (LIPI-1). PCR revealed that the most prevalent serogroup was serogroup III (1/2b, 3b, and 7 (n = 18, 66.65%)), followed by serogroup IV (4b, 4d-4e (n = 5, 27.7%)) and serogroup I (1/2a-3a (n = 1, 5.5%)). The assessment of the ability to develop biofilms using a crystal violet staining method revealed that L. monocytogenes responded to supplement medium TSBA, 1/10 diluted TSBA, and TSB in comparison with 1/10 diluted TSB (p < 0.05) on polystyrene at 240 h (p < 0.05). In particular, the biofilm formation by L. monocytogenes (7.78 ± 0.03-8.82 ± 0.03 log10 CFU/cm[2]) was significantly different in terms of TSBA on polypropylene type B (PP) (p < 0.05). In addition, visualization by epifluorescence microscopy, scanning electron microscopy (SEM), and treatment (DNase I and proteinase K) revealed the metabolically active cells and extracellular polymeric substances of biofilms on PP. L. monocytogenes has the ability to develop biofilms that harbor virulence-associated genes, which represent a serious threat to human health and food safety.}, } @article {pmid34572723, year = {2021}, author = {Pinheiro, ET and Karygianni, L and Attin, T and Thurnheer, T}, title = {Antibacterial Effect of Sodium Hypochlorite and EDTA in Combination with High-Purity Nisin on an Endodontic-like Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34572723}, issn = {2079-6382}, support = {2019/12908-3//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {Antimicrobial peptides have been proposed as antibiofilm agents. Therefore, we evaluated the effect of endodontic irrigants combined or not with the antimicrobial peptide nisin against an endodontic biofilm model composed of eleven bacterial species. Biofilms were grown on hydroxyapatite discs for 3, 15 and 21 days and treated with 1.5% sodium hypochlorite (NaOCl) or 17% EDTA followed by high-purity nisin (nisin ZP) or saline for 5 min each. Differences between groups were tested by two-way ANOVA and Tukey's multiple comparisons test (p < 0.05). Treatment with 1.5% NaOCl completely eliminated 3-d and 15-d biofilms but did not eradicate 21-d biofilms. Treatment with 1.5% NaOCl and 17% EDTA was equally effective against 21-d biofilms, showing 5-log and 4-log cell reduction, respectively, compared to the untreated control (9 log10, p < 0.05). No significant difference was found between 1.5% NaOCl + nisin ZP and 1.5% NaOCl in 21-d biofilms (p > 0.05). Likewise, no significant difference was found between 17% EDTA + nisin ZP and 17% EDTA treatments (p > 0.05). In conclusion, 1.5% NaOCl or 17% EDTA were effective strategies to combat mature biofilms. The additional use of nisin did not improve the activity of conventional irrigants against multispecies biofilms.}, } @article {pmid34572716, year = {2021}, author = {Gajdács, M and Baráth, Z and Kárpáti, K and Szabó, D and Usai, D and Zanetti, S and Donadu, MG}, title = {No Correlation between Biofilm Formation, Virulence Factors, and Antibiotic Resistance in Pseudomonas aeruginosa: Results from a Laboratory-Based In Vitro Study.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34572716}, issn = {2079-6382}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) possesses a plethora of virulence determinants, including the production of biofilm, pigments, exotoxins, proteases, flagella, and secretion systems. The aim of our present study was to establish the relationship between biofilm-forming capacity, the expression of some important virulence factors, and the multidrug-resistant (MDR) phenotype in P. aeruginosa. A total of three hundred and two (n = 302) isolates were included in this study. Antimicrobial susceptibility testing and phenotypic detection of resistance determinants were carried out; based on these results, isolates were grouped into distinct resistotypes and multiple antibiotic resistance (MAR) indices were calculated. The capacity of isolates to produce biofilm was assessed using a crystal violet microtiter-plate based method. Motility (swimming, swarming, and twitching) and pigment-production (pyoverdine and pyocyanin) were also measured. Pearson correlation coefficients (r) were calculated to determine for antimicrobial resistance, biofilm-formation, and expression of other virulence factors. Resistance rates were the highest for ceftazidime (56.95%; n = 172), levofloxacin (54.97%; n = 166), and ciprofloxacin (54.64%; n = 159), while lowest for colistin (1.66%; n = 5); 44.04% (n = 133) of isolates were classified as MDR. 19.87% (n = 60), 20.86% (n = 63) and 59.27% (n = 179) were classified as weak, moderate, and strong biofilm producers, respectively. With the exception of pyocyanin production (0.371 ± 0.193 vs. non-MDR: 0.319 ± 0.191; p = 0.018), MDR and non-MDR isolates did not show significant differences in expression of virulence factors. Additionally, no relevant correlations were seen between the rate of biofilm formation, pigment production, or motility. Data on interplay between the presence and mechanisms of drug resistance with those of biofilm formation and virulence is crucial to address chronic bacterial infections and to provide strategies for their management.}, } @article {pmid34572697, year = {2021}, author = {Lin, HL and Chiang, CE and Lin, MC and Kau, ML and Lin, YT and Chen, CS}, title = {Aerosolized Hypertonic Saline Hinders Biofilm Formation to Enhance Antibiotic Susceptibility of Multidrug-Resistant Acinetobacter baumannii.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34572697}, issn = {2079-6382}, support = {CMRPD1K0181//Chang Gung Medical Foundation/ ; 109-2314-B-182-067; 109-2314-B-182-067-003//Ministry of Science and Technology, Taiwan/ ; }, abstract = {Limited therapeutic options are available for multidrug-resistant Acinetobacter baumannii (MDR-AB), and the development of effective treatments is urgently needed. The efficacy of four aerosolized antibiotics (gentamicin, amikacin, imipenem, and meropenem) on three different MDR-AB strains was evaluated using hypertonic saline (HS, 7 g/100 mL) as the aerosol carrier. HS aerosol effectively hindered biofilm formation by specific MDR-AB strains. It could also interrupt the swarming dynamics of MDR-AB and the production of extracellular polymeric substances, which are essential for biofilm progression. Biofilms protect the microorganisms from antibiotics. The use of HS aerosol as a carrier resulted in a decreased tolerance to gentamicin and amikacin in the biofilm-rich MDR-AB. Moreover, we tested the aerosol characteristics of antibiotics mixed with HS and saline, and results showed that HS enhanced the inhaled delivery dose with a smaller particle size distribution of the four antibiotics. Our findings demonstrate the potential of using "old" antibiotics with our "new" aerosol carrier, and potentiate an alternative therapeutic strategy to eliminate MDR-AB infections from a biofilm-disruption perspective.}, } @article {pmid34572664, year = {2021}, author = {Sengupta, M and Sarkar, S and SenGupta, M and Ghosh, S and Sarkar, R and Banerjee, P}, title = {Biofilm Producing Enterococcus Isolates from Vaginal Microbiota.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34572664}, issn = {2079-6382}, abstract = {BACKGROUND: Enterococcus is an important cause of infection in the hospital as well as in the community.

METHODS: A prospective study was done in Medical College, Kolkata for a period of 2 years (from January 2018 to December 2019). After obtaining clearance from the Institutional Ethics Committee, Enterococcus isolates from cases of vaginitis were included in the study. Identification of Enterococcus species was done by Gram stain and conventional biochemical tests along with automated identification by VITEK 2 Compact. These isolates were tested for antimicrobial susceptibility to different antibiotics by Kirby Bauer disc diffusion method and minimum inhibitory concentration (MIC) by VITEK 2 Compact. Interpretation of susceptibility was done according to the Clinical and Laboratory Standards Institute (CLSI) 2017 guidelines. Biofilm detection for Enterococcus species was done.

RESULTS: During the period of 2 years, 39 isolates of Enterococcus spp. were obtained from vaginitis cases. Among these, 27 were Enterococcus faecalis and 12 Enterococcus faecium. All isolates were highly susceptible to vancomycin, teicoplanin, and linezolid. Biofilm was detected in eight isolates of which five were strong biofilm producer and three moderate biofilm producers.

CONCLUSION: Biofilm production is an important virulence factor in Enterococcus isolates from vaginitis.}, } @article {pmid34572641, year = {2021}, author = {Pant, N and Eisen, DP}, title = {Non-Antimicrobial Adjuvant Strategies to Tackle Biofilm-Related Staphylococcus aureus Prosthetic Joint Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {9}, pages = {}, pmid = {34572641}, issn = {2079-6382}, abstract = {Staphylococcus aureus frequently causes community- and hospital-acquired infections. S. aureus attachment followed by biofilm formation on tissues and medical devices plays a significant role in the establishment of chronic infections. Staphylococcal biofilms encase bacteria in a matrix and protect the cells from antimicrobials and the immune system, resulting in infections that are highly resistant to treatment. The biology of biofilms is complex and varies between organisms. In this review, we focus our discussion on S. aureus biofilms and describe the stages of their formation. We particularly emphasize genetic and biochemical processes that may be vulnerable to novel treatment approaches. Against this background, we discuss treatment strategies that have been successful in animal models of S. aureus biofilm-related infection and consider their possible use for the prevention and eradication of biofilm-related S. aureus prosthetic joint infection.}, } @article {pmid34570460, year = {2021}, author = {Tan, GR and Hsu, CS and Zhang, Y}, title = {pH-Responsive Hybrid Nanoparticles for Imaging Spatiotemporal pH Changes in Biofilm-Dentin Microenvironments.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {39}, pages = {46247-46259}, doi = {10.1021/acsami.1c11162}, pmid = {34570460}, issn = {1944-8252}, mesh = {Beverages/adverse effects ; Biofilms ; Cellular Microenvironment/*physiology ; Dental Caries/*metabolism ; Dentin/diagnostic imaging/*metabolism ; Fluorescent Dyes/*chemistry ; Humans ; Hydrogen-Ion Concentration ; Methylene Blue/chemistry ; Nanoparticles/*chemistry ; Protein Corona/chemistry ; Silicon Dioxide/chemistry ; Streptococcus mutans/metabolism/physiology ; Tooth/metabolism ; }, abstract = {Engineering highly sensitive nanomaterials to monitor spatiotemporal pH changes has rather broad applications in studying various biological systems. Intraoral/biofilm-tooth pH is the single parameter that has demonstrated accurate assessment of dental caries risk, reflecting the summative integrated outcome of the complicated interactions between three etiological factors, namely, microorganisms/biofilm, diet/carbohydrates, and tooth/saliva/host. However, there is little to no technology/system capable of accurately probing simultaneously both the micro-pH profiles in dentin tissues and acidogenic oral biofilms and examining the pathophysiologic acid attacks with high spatial/temporal resolution. Therefore, a highly sensitive pH-responsive hybrid nanoparticle (pH-NP) is developed and coupled with an ex vivo tooth-biofilm caries model to simulate and study the key cariogenic determinants/steps. The pH-NP emits two distinct fluorescences with mutually inversely proportional intensities that vary accordingly to the proximity pH and with a ratiometric output sensitivity of 13.4-fold across a broad clinically relevant pH range of 3.0-8.0. Using [H[+]], in addition to pH, to calculate the "area-under-curve" corroborates the "minimum-pH" in semiquantifying the demineralizing potential in each biofilm-dentin zones/depth. The data mechanistically elucidates a two-pronged cariogenic effect of a popular-acidic-sweet-drink, in inundating the biofilm/tooth-system with H[+] ions from both the drink and the metabolic byproducts of the biofilm.}, } @article {pmid34569158, year = {2022}, author = {Javadiyan, S and Cooksley, CM and Bouras, GS and Kao, SS and Bennett, CA and Wormald, PJ and Vreugde, S and Psaltis, AJ}, title = {Investigation of Kappa Carrageenan's muco-adhesive, antibacterial, and anti-biofilm properties.}, journal = {International forum of allergy & rhinology}, volume = {12}, number = {3}, pages = {302-305}, doi = {10.1002/alr.22899}, pmid = {34569158}, issn = {2042-6984}, mesh = {*Adhesives ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Carrageenan ; Humans ; }, } @article {pmid34567189, year = {2021}, author = {Yousefpour, Z and Davarzani, F and Owlia, P}, title = {Evaluating of the Effects of Sub-MIC Concentrations of Gentamicin on Biofilm Formation in Clinical Isolates of Pseudomonas aeruginosa.}, journal = {Iranian journal of pathology}, volume = {16}, number = {4}, pages = {403-410}, pmid = {34567189}, issn = {1735-5303}, abstract = {BACKGROUND & OBJECTIVE: The ability of Pseudomonas aeruginosa to form biofilm has an important role in establishment of chronic phase of infections. Biofilm formation can be affected by antibiotics sub-MIC concentrations. The principal aim of the present study was to evaluate the effect of gentamicin at sub-MIC concentrations on biofilm formation in 100 Pseudomonas aeruginosa clinical isolates.

METHODS: Determination of minimal inhibitory concentration of gentamicin for clinical isolates was done using micro broth dilution method. The amount of biofilm formation in the treated and untreated isolates with gentamicin sub-MIC (1/2&1/4MIC) concentrations was evaluated using microtitre plate assay. pelA and pslA genes were detected in clinical isolates by PCR method.

RESULTS: 99% of clinical isolates were biofilm producer. Different changes in amount of biofilm formation were observed in the treated clinical isolates with sub-MIC concentrations of gentamicin. Two dominant changes were observed in 80% of clinical isolates. These concentrations had inhibitory effect on biofilm formation in 46.4% of isolates and caused a significant decrease in its amount. While in 31.3% of the isolates, the biofilm formation was significantly increased. The frequency of pelA and pslA genes among clinical isolates was 100%.

CONCLUSION: gentamicin sub-MIC concentrations cause different changes on biofilm formation of Pseudomonas aeruginosa clinical isolates. Therefore, further studies are needed for discovering new treatment strategies and using sub-MIC concentrations of the antibiotic in prevention and treatment of Pseudomonas aeruginosa infections.}, } @article {pmid34567162, year = {2021}, author = {Memar, MY and Adibkia, K and Farajnia, S and Samadi Kafil, H and Khalili, Y and Azargun, R and Ghotaslou, R}, title = {In-vitro Effect of Imipenem, Fosfomycin, Colistin, and Gentamicin Combination against Carbapenem-resistant and Biofilm-forming Pseudomonas aeruginosa Isolated from Burn Patients.}, journal = {Iranian journal of pharmaceutical research : IJPR}, volume = {20}, number = {2}, pages = {286-296}, pmid = {34567162}, issn = {1735-0328}, abstract = {The aim of this study was to investigate in-vitro antibacterial and antibiofilm effect of colistin, imipenem, gentamicin, and fosfomycin alone and the various combinations against carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa). Eight carbapenem-resistant and biofilm-forming P. aeruginosa isolates from burn patients were collected. The mechanisms of resistance to carbapenem were determined by the phenotypic, PCR, and Real-Time PCR assays. The minimum inhibitory concentration (MIC) of antimicrobial agents was determined by the broth micro dilution. To detect any inhibitory effect of antibiotics against the biofilm, the biofilm inhibitory concentration was determined. To detect synergetic effects of the combinations of antibiotics, the checkerboard assay and the fractional inhibitory concentration (FIC) were used. The highest synergic effect was observed in colistin/fosfomycin and gentamicin/fosfomycin (5 of 8 isolates), and the lowest synergic effect was found in gentamicin/imipenem and colistin/gentamicin (1 of 8 isolates). Colistin/fosfomycin, imipenem/fosfomycin, colistin/imipenem, gentamicin/fosfomycin, and gentamicin/imipenem were shown synergic effect for 3, 2, 2, 2 and 1 isolates, respectively. The combination of antibiotics had different effects on biofilm and planktonic forms of P. aeruginosa. Therefore, a separate determination of inhibitory effects of the antibiotic in the combination is necessary. Fosfomycin/colistin and fosfomycin/gentamicin were more effective against planktonic form and fosfomycin/colistin against biofilm forms.}, } @article {pmid34566936, year = {2021}, author = {Poulin, MB and Kuperman, LL}, title = {Regulation of Biofilm Exopolysaccharide Production by Cyclic Di-Guanosine Monophosphate.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {730980}, pmid = {34566936}, issn = {1664-302X}, abstract = {Many bacterial species in nature possess the ability to transition into a sessile lifestyle and aggregate into cohesive colonies, known as biofilms. Within a biofilm, bacterial cells are encapsulated within an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, nucleic acids, lipids, and other small molecules. The transition from planktonic growth to the biofilm lifecycle provides numerous benefits to bacteria, such as facilitating adherence to abiotic surfaces, evasion of a host immune system, and resistance to common antibiotics. As a result, biofilm-forming bacteria contribute to 65% of infections in humans, and substantially increase the energy and time required for treatment and recovery. Several biofilm specific exopolysaccharides, including cellulose, alginate, Pel polysaccharide, and poly-N-acetylglucosamine (PNAG), have been shown to play an important role in bacterial biofilm formation and their production is strongly correlated with pathogenicity and virulence. In many bacteria the biosynthetic machineries required for assembly of these exopolysaccharides are regulated by common signaling molecules, with the second messenger cyclic di-guanosine monophosphate (c-di-GMP) playing an especially important role in the post-translational activation of exopolysaccharide biosynthesis. Research on treatments of antibiotic-resistant and biofilm-forming bacteria through direct targeting of c-di-GMP signaling has shown promise, including peptide-based treatments that sequester intracellular c-di-GMP. In this review, we will examine the direct role c-di-GMP plays in the biosynthesis and export of biofilm exopolysaccharides with a focus on the mechanism of post-translational activation of these pathways, as well as describe novel approaches to inhibit biofilm formation through direct targeting of c-di-GMP.}, } @article {pmid34566913, year = {2021}, author = {Matar, GK and Ali, M and Bagchi, S and Nunes, S and Liu, WT and Saikaly, PE}, title = {Relative Importance of Stochastic Assembly Process of Membrane Biofilm Increased as Biofilm Aged.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {708531}, pmid = {34566913}, issn = {1664-302X}, abstract = {The relative importance of different ecological processes controlling biofilm community assembly over time on membranes with different surface characteristics has never been investigated in membrane bioreactors (MBRs). In this study, five ultrafiltration hollow-fiber membranes - having identical nominal pore size (0.1μm) but different hydrophobic or hydrophilic surface characteristics - were operated simultaneously in the same MBR tank with a constant flux of 10 liters per square meter per hour (LMH). In parallel, membrane modules operated without permeate flux (0 LMH) were submerged in the same MBR tank, to investigate the passive microbial adsorption onto different hydrophobic or hydrophilic membranes. Samples from the membrane biofilm were collected after 1, 10, 20, and 30days of continuous filtration. The membrane biofilm microbiome were investigated using 16S rRNA gene amplicon sequencing from DNA and cDNA samples. Similar beta diversity trends were observed for both DNA- and cDNA-based analyses. Beta diversity analyses revealed that the nature of the membrane surface (i.e., hydrophobic vs. hydrophilic) did not seem to have an effect in shaping the bacterial community, and a similar biofilm microbiome evolved for all types of membranes. Similarly, membrane modules operated with and without permeate flux did not significantly influence alpha and beta diversity of the membrane biofilm. Nevertheless, different-aged membrane biofilm samples exhibited significant differences. Proteobacteria was the most dominant phylum in early-stage membrane biofilm after 1 and 10days of filtration. Subsequently, the relative reads abundance of the phyla Bacteroidetes and Firmicutes increased within the membrane biofilm communities after 20 and 30days of filtration, possibly due to successional steps that lead to the formation of a relatively aged biofilm. Our findings indicate distinct membrane biofilm assembly patterns with different-aged biofilm. Ecological null model analyses revealed that the assembly of early-stage biofilm community developed after 1 and 10days of filtration was mainly governed by homogenous selection. As the biofilm aged (days 20 and 30), stochastic processes (e.g., ecological drift) started to become important in shaping the assembly of biofilm community.}, } @article {pmid34563667, year = {2021}, author = {Galdiero, E and Ricciardelli, A and D'Angelo, C and de Alteriis, E and Maione, A and Albarano, L and Casillo, A and Corsaro, MM and Tutino, ML and Parrilli, E}, title = {Pentadecanoic acid against Candida albicans-Klebsiella pneumoniae biofilm: towards the development of an anti-biofilm coating to prevent polymicrobial infections.}, journal = {Research in microbiology}, volume = {172}, number = {7-8}, pages = {103880}, doi = {10.1016/j.resmic.2021.103880}, pmid = {34563667}, issn = {1769-7123}, mesh = {Aldehydes/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/genetics/physiology ; Dimethylpolysiloxanes ; Fatty Acids/*pharmacology ; Gene Expression ; Genes, Bacterial ; Genes, Fungal ; Klebsiella pneumoniae/*drug effects/genetics/physiology ; Microbial Sensitivity Tests ; }, abstract = {The ability to form biofilms is a common feature of microorganisms, which can colonize a variety of surfaces, such as host tissues and medical devices, resulting in infections highly resistant to conventional drugs. This aspect is particularly critical in polymicrobial biofilms involving both fungi and bacteria, therefore, to eradicate such severe infections, new and effective anti-biofilm strategies are needed. The efficacy of pentadecanal and pentadecanoic acid as anti-biofilm agents has been recently reported against different bacterial strains. Their chemical similarity with diffusible signal factors (DSFs), plus the already known ability of fatty acids to act as anti-biofilm agents, suggested to explore their use against Candida albicans and Klebsiella pneumoniae mixed biofilm. In this work, we demonstrated the ability of both molecules to prevent the formation and destabilize the structure of the dual-species biofilm. Moreover, the pentadecanoic acid anti-biofilm coating, previously developed through the adsorption of the fatty acid on polydimethylsiloxane (PDMS), was proved to prevent the polymicrobial biofilm formation in dynamic conditions by confocal laser scanning microscopy analysis. Finally, the evaluation of the expression levels of some biofilm-related genes of C. albicans and K. pneumoniae treated with pentadecanoic acid provided some insights into the molecular mechanisms underpinning its anti-biofilm effect.}, } @article {pmid34563350, year = {2022}, author = {Lin, WS and Alfaifi, AA and Gregory, RL}, title = {Response to Letter to the Editor regarding the article "Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine".}, journal = {The Journal of prosthetic dentistry}, volume = {127}, number = {2}, pages = {373-374}, doi = {10.1016/j.prosdent.2021.08.017}, pmid = {34563350}, issn = {1097-6841}, mesh = {*Acrylic Resins ; Biofilms ; Caffeine ; *Candida albicans/physiology ; Denture Bases ; Nicotine ; }, } @article {pmid34562786, year = {2021}, author = {Wang, J and Zhu, J and Meng, J and Qiu, T and Wang, W and Wang, R and Liu, J}, title = {Baicalin inhibits biofilm formation by influencing primary adhesion and aggregation phases in Staphylococcus saprophyticus.}, journal = {Veterinary microbiology}, volume = {262}, number = {}, pages = {109242}, doi = {10.1016/j.vetmic.2021.109242}, pmid = {34562786}, issn = {1873-2542}, mesh = {Animals ; *Azithromycin ; *Bacterial Adhesion/drug effects ; Biofilms ; *Flavonoids/pharmacology ; Membrane Proteins/metabolism ; Mice ; *Staphylococcus saprophyticus/drug effects ; }, abstract = {The ability to form biofilms on surfaces makes Staphylococcus saprophyticus (S. saprophyticus) becomes the main pathogenic factor in nosocomial infections. Previously, we demonstrated that baicalin (Bac) inhibited azithromycin-resistant S. saprophyticus (ARSS) biofilm formation. This investigation aims to explore the influence of baicalin on primary adhesion and aggregation phases of biofilm formation, and the treatment effect of baicalin and azithromycin on ARSS biofilm-associated infection. Crystal violet (CV) staining and scanning electron microscope (SEM) observations clearly showed that sub-inhibitory concentration baicalin inhibited ARSS biofilm formation when baicalin was added before the adhesion and aggregation phases. Baicalin significantly increased the relative adhesion inhibition rate and decreased the rate of bacteria aggregation in a dose-dependent manner. Moreover, CLSM and cell lysis assays revealed that baicalin inhibited the production of surface proteins and cell autolysis in bacteria adhesion and aggregation phases of biofilm formation. Meanwhile, the relative expressions of adhesion-related and autolysis-related genes were down-regulated by baicalin. In vivo, the combination of baicalin and azithromycin succeeded in eradicating ARSS from the mouse cutaneous infection model and decreasing the pathological injuries, the expressions of cytokines in infected tissue, and the number of inflammatory cells in the blood. Simultaneously, baicalin decreased the bacterial burdens in tubes, the level of TNF-α, and the number of monocytes and neutrophils compared with that of the SS and azithromycin groups. Based on these results, baicalin inhibited the adhesion and aggregation phases of biofilm formation by influenced the production of surface proteins and cell autolysis. Baicalin and azithromycin synergetically treated ARSS biofilm-associated infection.}, } @article {pmid34562533, year = {2021}, author = {Zmejkoski, DZ and Zdravković, NM and Trišić, DD and Budimir, MD and Marković, ZM and Kozyrovska, NO and Todorović Marković, BM}, title = {Chronic wound dressings - Pathogenic bacteria anti-biofilm treatment with bacterial cellulose-chitosan polymer or bacterial cellulose-chitosan dots composite hydrogels.}, journal = {International journal of biological macromolecules}, volume = {191}, number = {}, pages = {315-323}, doi = {10.1016/j.ijbiomac.2021.09.118}, pmid = {34562533}, issn = {1879-0003}, mesh = {Adult ; Anti-Bacterial Agents/*chemistry/pharmacology ; *Bandages, Hydrocolloid ; Biofilms/drug effects ; Cells, Cultured ; Cellulose/*chemistry ; Chitosan/*chemistry ; Humans ; Nanogels/*chemistry ; }, abstract = {Since the pathogenic bacteria biofilms are involved in 70% of chronic infections and their resistance to antibiotics is increased, the research in this field requires new healing agents. New composite hydrogels were designed as potential chronic wound dressings composed of bacterial cellulose (BC) with chitosan polymer (Chi) - BC-Chi and chitosan nanoparticles (nChiD) - BC-nChiD. nChiD were obtained by gamma irradiation at doses: 20, 40 and 60 kGy. Physical and chemical analyses showed incorporation of Chi and encapsulation of nChiD into BC. The BC-Chi has the highest average surface roughness. BC-nChiD hydrogels show an irradiated dose-dependent increase of average surface roughness. New composite hydrogels are biocompatible with excellent anti-biofilm potential with up to 90% reduction of viable biofilm and up to 65% reduction of biofilm height. The BC-nChiD showed better dressing characteristics: higher porosity, higher wound fluid absorption and faster migration of cells (in vitro healing). All obtained results confirmed both composite hydrogels as promising chronic wound healing agents.}, } @article {pmid34558030, year = {2021}, author = {Wang, D and Bai, P and Zhang, B and Su, X and Jiang, X and Fang, T and Wang, J and Liu, C}, title = {Decreased biofilm formation in Proteus mirabilis after short-term exposure to a simulated microgravity environment.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {4}, pages = {2021-2030}, pmid = {34558030}, issn = {1678-4405}, mesh = {*Biofilms ; *Environmental Microbiology ; Extraterrestrial Environment ; Humans ; Proteus mirabilis/*physiology ; *Weightlessness ; }, abstract = {BACKGROUND: Microbes threaten human health in space exploration. Studies have shown that Proteus mirabilis has been found in human space habitats. In addition, the biological characteristics of P. mirabilis in space have been studied unconditionally. The simulated microgravity environment provides a platform for understanding the changes in the biological characteristics of P. mirabilis.

OBJECTIVE: This study intends to explore the effect of simulated microgravity on P. mirabilis, the formation of P. mirabilis biofilm, and its related mechanism.

METHODS: The strange deformable rods were cultured continuously for 14 days under microgravity simulated in high-aspect rotating vessels (HARVs). The morphology, growth rate, metabolism, and biofilm formation of the strain were measured, and the phenotypic changes of P. mirabilis were evaluated. Transcriptome sequencing was used to detect differentially expressed genes under simulated microgravity and compared with phenotype.

RESULTS: The growth rate, metabolic ability, and biofilm forming ability of P. mirabilis were lower than those of normal gravity culture under the condition of simulated microgravity. Further analysis showed that the decrease of growth rate, metabolic ability, and biofilm forming ability may be caused by the downregulation of related genes (pstS, sodB, and fumC).

CONCLUSION: The simulated microgravity condition enables us to explore the potential relationship between bacterial phenotype and molecular biology, thus opening up a suitable and constructive method for medical fields that have not been explored before. It provides a certain strategy for the treatment of P. mirabilis infectious diseases in space environment by exploring the microgravity of P. mirabilis.}, } @article {pmid34558029, year = {2021}, author = {Rather, MA and Gupta, K and Mandal, M}, title = {Microbial biofilm: formation, architecture, antibiotic resistance, and control strategies.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {4}, pages = {1701-1718}, pmid = {34558029}, issn = {1678-4405}, support = {BT/PR16149/NER/95/85/ 2015//Department of Biotechnology , Ministry of Science and Technology/ ; TU/Fin/R/18-19/339//Tezpur University/ ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; *Bacterial Physiological Phenomena/drug effects ; *Biofilms/drug effects ; *Drug Resistance, Microbial/drug effects/genetics ; *Quorum Sensing/drug effects ; }, abstract = {The assembly of microorganisms over a surface and their ability to develop resistance against available antibiotics are major concerns of interest. To survive against harsh environmental conditions including known antibiotics, the microorganisms form a unique structure, referred to as biofilm. The mechanism of biofilm formation is triggered and regulated by quorum sensing, hostile environmental conditions, nutrient availability, hydrodynamic conditions, cell-to-cell communication, signaling cascades, and secondary messengers. Antibiotic resistance, escape of microbes from the body's immune system, recalcitrant infections, biofilm-associated deaths, and food spoilage are some of the problems associated with microbial biofilms which pose a threat to humans, veterinary, and food processing sectors. In this review, we focus in detail on biofilm formation, its architecture, composition, genes and signaling cascades involved, and multifold antibiotic resistance exhibited by microorganisms dwelling within biofilms. We also highlight different physical, chemical, and biological biofilm control strategies including those based on plant products. So, this review aims at providing researchers the knowledge regarding recent advances on the mechanisms involved in biofilm formation at the molecular level as well as the emergent method used to get rid of antibiotic-resistant and life-threatening biofilms.}, } @article {pmid34557273, year = {2021}, author = {Ghaioumy, R and Tabatabaeifar, F and Mozafarinia, K and Mianroodi, AA and Isaei, E and Morones-Ramírez, JR and Afshari, SAK and Kalantar-Neyestanaki, D}, title = {Biofilm formation and molecular analysis of intercellular adhesion gene cluster (icaABCD) among Staphylococcus aureus strains isolated from children with adenoiditis.}, journal = {Iranian journal of microbiology}, volume = {13}, number = {4}, pages = {458-463}, pmid = {34557273}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: It is well known that Staphylococcus aureus biofilm plays an important role in adenoiditis and biofilm resistance frequently results in failure of therapy. The goal of this study was to evaluate the biofilm production of S. aureus isolates obtained from adenoid specimens and assess the relationship between biofilm formation ability and ica operon genes.

MATERIALS AND METHODS: A total of 112 adenoid samples were obtained from patients under 15 years old with adenoid hypertrophy. All S. aureus isolates were initially identified by standard microbiological tests and amplification of nuc by polymerase chain reaction (PCR) technique. Biofilm formation of S. aureus isolates was evaluated and icaADBC genes were detected by PCR technique.

RESULTS: There were 46 isolates (41%) identified as S. aureus. The ability to produce biofilm was detected among total S. aureus isolates. Molecular study of ica operon revealed that 2 (6.3%) and 19 (59.4%) isolates carried icaA and icaD, respectively. The prevalence of icaA + icaD was seen among 11 (34.4%) S. aureus isolates, while icaC and icaB were not detected.

CONCLUSION: Our findings indicated that icaABCD operon are associated with biofilm formation in S. aureus isolates, however the absence of these genes may not necessarily exclude this property.}, } @article {pmid34557173, year = {2021}, author = {Franklin-Alming, FV and Kaspersen, H and Hetland, MAK and Bakksjø, RJ and Nesse, LL and Leangapichart, T and Löhr, IH and Telke, AA and Sunde, M}, title = {Exploring Klebsiella pneumoniae in Healthy Poultry Reveals High Genetic Diversity, Good Biofilm-Forming Abilities and Higher Prevalence in Turkeys Than Broilers.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {725414}, pmid = {34557173}, issn = {1664-302X}, abstract = {Klebsiella pneumoniae is a well-studied human pathogen for which antimicrobial resistant and hypervirulent clones have emerged globally. K. pneumoniae is also present in a variety of environmental niches, but currently there is a lack of knowledge on the occurrence and characteristics of K. pneumoniae from non-human sources. Certain environmental niches, e.g., animals, may be associated with high K. pneumoniae abundance, and these can constitute a reservoir for further transmission of strains and genetic elements. The aim of this study was to explore and characterize K. pneumoniae from healthy broilers and turkeys. A total of 511 cecal samples (broiler n = 356, turkey n = 155), included in the Norwegian monitoring program for antimicrobial resistance (AMR) in the veterinary sector (NORM-VET) in 2018, were screened for K. pneumoniae by culturing on SCAI agar. K. pneumoniae was detected in 207 (40.5%) samples. Among the broiler samples, 25.8% were positive for K. pneumoniae, in contrast to turkey with 74.2% positive samples (p < 0.01). Antibiotic susceptibility testing was performed, in addition to investigating biofilm production. Whole genome sequencing was performed on 203 K. pneumoniae isolates, and analysis was performed utilizing comparative genomics tools. The genomes grouped into 66 sequence types (STs), with ST35, ST4710 and ST37 being the most prevalent at 13.8%, 7.4%, and 5.4%, respectively. The overall AMR occurrence was low, with only 11.3% of the isolates showing both pheno- and genotypic resistance. Genes encoding aerobactin, salmochelin or yersiniabactin were detected in 47 (23.2%) genomes. Fifteen hypervirulent genomes belonging to ST4710 and isolated from turkey were identified. These all encoded the siderophore virulence loci iuc5 and iro5 on an IncF plasmid. Isolates from both poultry species displayed good biofilm-forming abilities with an average of OD595 0.69 and 0.64. To conclude, the occurrence of K. pneumoniae in turkey was significantly higher than in broiler, indicating that turkey might be an important zoonotic reservoir for K. pneumoniae compared to broilers. Furthermore, our results show a highly diverse K. pneumoniae population in poultry, low levels of antimicrobial resistance, good biofilm-forming abilities and a novel hypervirulent ST4710 clone circulating in the turkey population.}, } @article {pmid34557170, year = {2021}, author = {Lamret, F and Varin-Simon, J and Velard, F and Terryn, C and Mongaret, C and Colin, M and Gangloff, SC and Reffuveille, F}, title = {Staphylococcus aureus Strain-Dependent Biofilm Formation in Bone-Like Environment.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {714994}, pmid = {34557170}, issn = {1664-302X}, abstract = {Staphylococcus aureus species is an important threat for hospital healthcare because of frequent colonization of indwelling medical devices such as bone and joint prostheses through biofilm formations, leading to therapeutic failure. Furthermore, bacteria within biofilm are less sensitive to the host immune system responses and to potential antibiotic treatments. We suggested that the periprosthetic bone environment is stressful for bacteria, influencing biofilm development. To provide insights into S. aureus biofilm properties of three strains [including one methicillin-resistant S. aureus (MRSA)] under this specific environment, we assessed several parameters related to bone conditions and expected to affect biofilm characteristics. We reported that the three strains harbored different behaviors in response to the lack of oxygen, casamino acids and glucose starvation, and high concentration of magnesium. Each strain presented different biofilm biomass and live adherent cells proportion, or matrix production and composition. However, the three strains shared common responses in a bone-like environment: a similar production of extracellular DNA and engagement of the SOS response. This study is a step toward a better understanding of periprosthetic joint infections and highlights targets, which could be common among S. aureus strains and for future antibiofilm strategies.}, } @article {pmid34556107, year = {2021}, author = {Poornima, P and Krithikadatta, J and Ponraj, RR and Velmurugan, N and Kishen, A}, title = {Biofilm formation following chitosan-based varnish or chlorhexidine-fluoride varnish application in patients undergoing fixed orthodontic treatment: a double blinded randomised controlled trial.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {465}, pmid = {34556107}, issn = {1472-6831}, mesh = {Biofilms ; Cariostatic Agents ; *Chitosan ; Chlorhexidine ; *Dental Caries/prevention & control ; Female ; Fluorides ; Fluorides, Topical ; Humans ; Male ; *Orthodontic Brackets/adverse effects ; }, abstract = {BACKGROUND: Orthodontic treatment poses an increased risk of plaque accumulation and demineralisation of enamel leading to white spot lesion around the brackets. This parallel arm trial aims to assess the degree of bacterial plaque formation adjacent to orthodontic brackets, following the application of a chitosan-based varnish or chlorhexidene-fluoride varnish.

METHODS: A total of 200 teeth from 20 patients undergoing fixed orthodontic therapy were assessed and biofilm formation around the brackets were recorded using the Bonded Bracket Index (Plaque index) at baseline and weekly for 6 weeks. The bacterial count and plaque pH at corresponding weekly intervals were also recorded. Following bracket bonding, the patients were cluster randomised to receive chitosan-based varnish-CHS (UNO Gel Bioschell, Germiphene corp., Brantford, Canada) or chlorhexidine-fluoride varnish-CFV (Cervitec F, Ivoclar Vivadent, Schaan, Liechtenstein) every week on the representative teeth respectively. BBI proportions were compared between groups at all time intervals using Chi square test. Mean plaque bacterial count and plaque pH were compared using Mann Whitney U test and Tukey's HSD test respectively.

RESULTS: Baseline characteristics were similar between the groups: Mean age was CHS = 23 and CFV = 21; male to female ratio was CHS = 5/5, CFV = 7/3. At the end of 6 weeks, chitosan-based varnish performed equal to chlorhexidine-fluoride varnish (P > 0.05) with 98% and 95% of teeth with acceptable scores respectively. The plaque bacterial count significantly reduced at 6 weeks for both varnish compared to the baseline; The value for CHS was 0.43 ± 0.4 × 10[4] and CFV was 0.77 ± 0.64 × 10[4] CFU (P < 0.05), with no difference between both the varnishes. Both varnishes had no effect on the plaque pH that remained neutral.

CONCLUSION: This trial showed that both chitosan-based varnish and chlorhexidine-fluoride varnish reduced bacterial count, while the plaque pH remained neutral over a period of six weeks in patients undergoing fixed orthodontic therapy. The anti-plaque effects of the natural biopolymeric chitosan-based varnish was similar to that of chlorhexidine-fluoride varnish, a known chemotherapeutic agent. Registration: This trial protocol was registered with https://www.ctri.nic.in (CTRI/2019/05/018896). (Date of registration 02/05/2019).

PROTOCOL: The protocol was not published before trial commencement.}, } @article {pmid34554005, year = {2021}, author = {Martinez, JN and Nishihara, A and Haruta, S}, title = {Metagenome-Assembled Genome Sequences Recovered from Epilithic River Biofilm in the Tama River, Japan.}, journal = {Microbiology resource announcements}, volume = {10}, number = {38}, pages = {e0066421}, pmid = {34554005}, issn = {2576-098X}, support = {//Tokyu Foundation for a Better Environment/ ; }, abstract = {Draft genome sequences of putatively novel bacteria were assembled from the metagenome of epilithic biofilm samples collected from the Tama River (Tokyo, Japan). The metagenome contains 44,630,724 sequences, 44,792 contigs, and 48% G+C content. Binning resulted in 31 metagenome-assembled genomes (MAGs) with ≥50% completeness.}, } @article {pmid34554002, year = {2021}, author = {Rajeev, M and Sushmitha, TJ and Toleti, SR and Pandian, SK}, title = {Draft Genome Sequencing of Pseudoalteromonas tetraodonis Strain kknpp56, a Potent Biofilm-Forming Bacterium Isolated from Early-Stage Marine Biofilm.}, journal = {Microbiology resource announcements}, volume = {10}, number = {38}, pages = {e0060521}, pmid = {34554002}, issn = {2576-098X}, support = {51/14/06/2019-BRNS//DAE | Board of Research in Nuclear Sciences (BRNS)/ ; 51/14/06/2019-BRNS//DAE | Board of Research in Nuclear Sciences (BRNS)/ ; 51/14/06/2019-BRNS//DAE | Board of Research in Nuclear Sciences (BRNS)/ ; 51/14/06/2019-BRNS//DAE | Board of Research in Nuclear Sciences (BRNS)/ ; }, abstract = {Pseudoalteromonas tetraodonis strain kknpp56 is an exopolysaccharide (EPS)-producing marine bacterium that forms potent biofilm. To determine the biosynthesis pathways involved in the EPS production of this bacterium, whole-genome sequencing was performed. The complete genome comes from one chromosome containing 3.72 Mbp of DNA with a G+C content of 41%.}, } @article {pmid34553907, year = {2021}, author = {Wang, J and Guo, X and Xue, J}, title = {Biofilm-Developed Microplastics As Vectors of Pollutants in Aquatic Environments.}, journal = {Environmental science & technology}, volume = {55}, number = {19}, pages = {12780-12790}, doi = {10.1021/acs.est.1c04466}, pmid = {34553907}, issn = {1520-5851}, mesh = {Aquatic Organisms ; Biofilms ; Environmental Monitoring ; *Environmental Pollutants ; Microplastics ; Plastics ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microplastics are a big and growing part of global pollution, which has aroused increasing concern in recent years because of their large amount, wide distribution, and adverse effects. Microplastics can sorb various pollutants from aquatic environments and act as vectors of pollutants. Most studies mainly focused on the virgin microplastics. However, microplastics in environments can be easily colonized by microorganisms, and form biofilm, which will influence the behaviors and potential risks of microplastics. The formation of biofilm on microplastics and its effects on their properties have been studied before, but their sorption and transport behaviors, and potential risks for pollutants' transfer have not been reviewed. In this paper, the role of biofilm-developed microplastics as vectors of pollutants was thoroughly analyzed and summarized. First, the formation of biofilm on microplastics, the compositions of microorganisms in biofilm, the influencing factors, and the property changes of microplastics after biofilm attachment are thoroughly reviewed. Second, the sorption of pollutants onto biofilm-developed microplastics is discussed. Third, the role of biofilm-developed microplastics as vector of pollutants are analyzed. We concluded that microplastics could provide unique substrates for microorganisms. Biofilm-developed microplastics can sorb more pollutants than the virgin ones, then act as vectors to introduce pollutants and attached microorganisms to aquatic environments and to organisms.}, } @article {pmid34550756, year = {2021}, author = {Stanford, K and Tran, F and Zhang, P and Yang, X}, title = {Biofilm-Forming Capacity of Escherichia coli Isolated from Cattle and Beef Packing Plants: Relation to Virulence Attributes, Stage of Processing, Antimicrobial Interventions, and Heat Tolerance.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {23}, pages = {e0112621}, pmid = {34550756}, issn = {1098-5336}, support = {2021r014R//Results Driven Agriculture/ ; FOS 01.17//Beef Cattle Research Council (BCRC)/ ; }, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Biofilms/*growth & development ; Cattle ; Cellulose ; Escherichia coli/*growth & development/pathogenicity ; Food Contamination ; Food Industry ; Red Meat/*microbiology ; *Thermotolerance ; Virulence ; }, abstract = {Despite the importance of biofilm formation in the contamination of meat by pathogenic Escherichia coli at slaughter plants, drivers for biofilm remain unclear. To identify selection pressures for biofilm, we evaluated 745 isolates from cattle and 700 generic E. coli isolates from two beef slaughter plants for motility, the expression of curli and cellulose, and biofilm-forming potential. Cattle isolates were also screened for serogroup, stx1, stx2, eae, and rpoS. Generic E. coli isolates were compared by source (hide of carcass, hide-off carcass, and processing equipment) before and after the implementation of antimicrobial hurdles. The proportion of E. coli isolates capable of forming biofilms was lowest (7.1%; P < 0.05) for cattle isolates and highest (87.3%; P < 0.05) from equipment. Only one enterohemorrhagic E. coli (EHEC) isolate was an extremely strong biofilm former, in contrast to 73.4% of E. coli isolates from equipment. Isolates from equipment after sanitation had a greater biofilm-forming capacity (P < 0.001) than those before sanitation. Most cattle isolates were motile and expressed curli, although these traits along with the expression of cellulose and the detection of rpoS were not necessary for biofilm formation. In contrast, isolates capable of forming biofilms on equipment were almost exclusively motile and able to express curli. The results of the present study indicate that cattle rarely carry EHEC capable of making strong biofilms in slaughter plants. However, if biofilm-forming EHEC contaminates equipment, current sanitation procedures may not eliminate the most robust biofilm-forming strains. Accordingly, new and effective antibiofilm hurdles for meat-processing equipment are required to reduce future instances of foodborne disease. IMPORTANCE As the majority of enterohemorrhagic E. coli (EHEC) isolates are not capable of forming biofilms, sources were undetermined for biofilm-forming EHEC isolated from "high-event periods" in beef slaughter plants. This study demonstrated that sanitation procedures used on beef-processing equipment may inadvertently lead to the survival of robust biofilm-forming strains of E. coli. Cattle only rarely carry EHEC capable of forming strong biofilms (1/745 isolates evaluated), but isolates with greater biofilm-forming capacity were more likely (P < 0.001) to survive equipment sanitation. In contrast, chilling carcasses for 3 days at 0°C reduced (P < 0.05) the proportion of biofilm-forming E. coli. Consequently, an additional antibiofilm hurdle for meat-processing equipment, perhaps involving cold exposure, is necessary to further reduce the risk of foodborne disease.}, } @article {pmid34550209, year = {2021}, author = {Silva, AMCMD and Costa Júnior, SD and Lima, JLC and Farias Filho, JLB and Cavalcanti, IMF and Maciel, MAV}, title = {Investigation of the association of virulence genes and biofilm production with infection and bacterial colonization processes in multidrug-resistant Acinetobacter spp.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {93}, number = {suppl 3}, pages = {e20210245}, doi = {10.1590/0001-3765202120210245}, pmid = {34550209}, issn = {1678-2690}, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; Virulence/genetics ; }, abstract = {The aim of this study was to evaluate the phenotypic and molecular patterns of biofilm formation in infection and colonization isolates of Acinetobacter spp. from patients who were admitted in a public hospital of Recife-PE-Brazil in 2018-2019. For the biofilm phenotypic analysis, Acinetobacter spp. isolates were evaluated by the crystal violet staining method; the search of virulence genes (bap, ompA, epsA, csuE and bfmS) was performed by PCR; and the ERIC-PCR was performed for molecular typing. Amongst the 38 Acinetobacter spp. isolates, 20 were isolated from infections and 18 from colonization. The resistance profile pointed that 86.85% (33/38) of the isolates were multidrug-resistant, being three infection isolates, and two colonization isolates resistant to polymyxin B. All the isolates were able to produce biofilm and they had at least one of the investigated virulence genes on their molecular profile, but the bap gene was found in 100% of them. No clones were detected by ERIC-PCR. There was no correlation between biofilm formation and the resistance profile of the bacteria, neither to the molecular profile of the virulence genes. Thus, the ability of Acinetobacter spp. to form biofilm is probably related to the high frequency of virulence genes.}, } @article {pmid34550006, year = {2021}, author = {Wu, Y and Meng, Y and Qian, L and Ding, B and Han, H and Chen, H and Bai, L and Qu, D and Wu, Y}, title = {The Vancomycin Resistance-Associated Regulatory System VraSR Modulates Biofilm Formation of Staphylococcus epidermidis in an ica-Dependent Manner.}, journal = {mSphere}, volume = {6}, number = {5}, pages = {e0064121}, pmid = {34550006}, issn = {2379-5042}, mesh = {Animals ; Bacterial Proteins/genetics ; *Biofilms ; Female ; Gene Deletion ; *Gene Expression Profiling ; Microbial Sensitivity Tests ; *Operon ; Polysaccharides, Bacterial ; Rabbits ; Real-Time Polymerase Chain Reaction ; Staphylococcus epidermidis/*drug effects/*genetics ; *Vancomycin Resistance ; }, abstract = {The two-component system VraSR responds to the cell wall-active antibiotic stress in Staphylococcus epidermidis. To study its regulatory function in biofilm formation, a vraSR deletion mutant (ΔvraSR) was constructed using S. epidermidis strain 1457 (SE1457) as the parent strain. Compared to SE1457, the ΔvraSR mutant showed impaired biofilm formation both in vitro and in vivo with a higher ratio of dead cells within the biofilm. Consistently, the ΔvraSR mutant produced much less polysaccharide intercellular adhesin (PIA). The ΔvraSR mutant also showed increased susceptibility to the cell wall inhibitor and SDS, and its cell wall observed under a transmission electron microscope (TEM) appeared to be thinner and interrupted, which is in accordance with higher susceptibility to the stress. Complementation of vraSR in the ΔvraSR mutant restored the biofilm formation and the cell wall thickness to wild-type levels. Transcriptome sequencing (RNA-Seq) showed that the vraSR deletion affected the transcription levels of 73 genes, including genes involved in biofilm formation, bacterial programmed cell death (CidA-LrgAB system), glycolysis/gluconeogenesis, the pentose phosphate pathway (PPP), and the tricarboxylic acid (TCA) cycle, etc. The results of RNA-Seq were confirmed by quantitative real-time reverse transcription-PCR (qRT-PCR). In the ΔvraSR mutant, the expression of icaA and lrgAB was downregulated and the expression of icaR and cidA was upregulated, in comparison to that of SE1457. The transcriptional levels of antibiotic-resistant genes (pbp2, serp1412, murAA, etc.) had no significant changes. An electrophoretic mobility shift assay further revealed that phosphorylated VraR bound to the promoter regions of the ica operon, as well as its own promoter region. This study demonstrates that in S. epidermidis, VraSR is an autoregulator and directly regulates biofilm formation in an ica-dependent manner. Upon cell wall stress, it indirectly regulates cell death and drug resistance in association with alterations to multiple metabolism pathways. IMPORTANCE S. epidermidis is a leading cause of hospital-acquired catheter-related infections, and its pathogenicity depends mostly on its ability to form biofilms on implants. The biofilm formation is a complex procedure that involves multiple regulating factors. Here, we show that a vancomycin resistance-associated two-component regulatory system, VraSR, plays an important role in modulating S. epidermidis biofilm formation and tolerance to stress. We demonstrate that S. epidermidis VraSR is an autoregulated system that selectively responds to stress targeting cell wall synthesis. Besides, phosphorylated VraR can bind to the promoter region of the ica operon and directly regulates polysaccharide intercellular adhesin production and biofilm formation in S. epidermidis. Furthermore, VraSR may indirectly modulate bacterial cell death and extracellular DNA (eDNA) release in biofilms through the CidA-LrgAB system. This work provides a new molecular insight into the mechanisms of VraSR-mediated modulation of the biofilm formation and cell death of S. epidermidis.}, } @article {pmid34548785, year = {2021}, author = {Amankwah, S and Abdella, K and Kassa, T}, title = {Bacterial Biofilm Destruction: A Focused Review On The Recent Use of Phage-Based Strategies With Other Antibiofilm Agents.}, journal = {Nanotechnology, science and applications}, volume = {14}, number = {}, pages = {161-177}, pmid = {34548785}, issn = {1177-8903}, abstract = {Biofilms are bacterial communities that live in association with biotic or abiotic surfaces and enclosed in an extracellular polymeric substance. Their formation on both biotic and abiotic surfaces, including human tissue and medical device surfaces, pose a major threat causing chronic infections. In addition, current antibiotics and antiseptic agents have shown limited ability to completely remove biofilms. In this review, the authors provide an overview on the formation of bacterial biofilms and its characteristics, burden and evolution with phages. Moreover, the most recent possible use of phages and phage-derived enzymes to combat bacteria in biofilm structures is elucidated. From the emerging results, it can be concluded that despite successful use of phages and phage-derived products in destroying biofilms, they are mostly not adequate to eradicate all bacterial cells. Nevertheless, a combined therapy with the use of phages and/or phage-derived products with other antimicrobial agents including antibiotics, nanoparticles, and antimicrobial peptides may be effective approaches to remove biofilms from medical device surfaces and to treat their associated infections in humans.}, } @article {pmid34546549, year = {2022}, author = {Mukhi, M and Vishwanathan, AS}, title = {Identifying potential inhibitors of biofilm-antagonistic proteins to promote biofilm formation: a virtual screening and molecular dynamics simulations approach.}, journal = {Molecular diversity}, volume = {26}, number = {4}, pages = {2135-2147}, pmid = {34546549}, issn = {1573-501X}, mesh = {Biofilms ; Ligands ; Molecular Docking Simulation ; *Molecular Dynamics Simulation ; *Proteins/chemistry ; }, abstract = {Microbial biofilms play a critical role in environmental biotechnology and associated applications. Biofilm production can be enhanced by inhibiting the function of proteins that negatively regulate their formation. With this objective, an in silico approach was adopted to identify competitive inhibitors of eight biofilm-antagonistic proteins, namely AbrB and SinR (from Bacillus subtilis) and AmrZ, PDE (EAL), PslG, RetS, ShrA and TpbA (from Pseudomonas aeruginosa). Fifteen inhibitors that structurally resembled the natural ligand of each protein were shortlisted using ligand-based and structure-based virtual screening. The top four inhibitors obtained from molecular docking using Autodock Vina were further docked using SwissDock and DOCK 6.9 to obtain a consensus hit for each protein based on different scoring functions. Further analysis of the protein-ligand complexes revealed that these top inhibitors formed significant non-covalent interactions with their respective protein binding sites. The eight protein-ligand complexes were then subjected to molecular dynamics simulations for 30 ns using GROMACS. RMSD and radius of gyration values of 0.1-0.4 nm and 1.0-3.5 nm, respectively, along with hydrogen bond formation throughout the trajectory indicated that all the complexes remained stable, compact and intact during the simulation period. Binding energy values between -20 and -77 kJ/mol obtained from MM-PBSA calculations further confirmed the high affinities of the eight inhibitors for their respective receptors. The outcome of this study holds great promise to enhance biofilms that are central to biotechnological processes associated with microbial electrochemical technologies, wastewater treatment, bioremediation and the industrial production of value-added products.}, } @article {pmid34543761, year = {2021}, author = {Ali Mohammed, MM and Pettersen, VK and Nerland, AH and Wiker, HG and Bakken, V}, title = {Label-free quantitative proteomic analysis of the oral bacteria Fusobacterium nucleatum and Porphyromonas gingivalis to identify protein features relevant in biofilm formation.}, journal = {Anaerobe}, volume = {72}, number = {}, pages = {102449}, doi = {10.1016/j.anaerobe.2021.102449}, pmid = {34543761}, issn = {1095-8274}, mesh = {Bacterial Proteins/*metabolism ; Bacteroidaceae Infections/*microbiology ; *Biofilms ; Chromatography, Liquid ; Computational Biology/methods ; Data Analysis ; Fusobacterium Infections/*microbiology ; Fusobacterium nucleatum/*metabolism ; Humans ; Mass Spectrometry ; Microbiota ; Mouth/microbiology ; Porphyromonas gingivalis/*metabolism ; *Proteome ; Proteomics/*methods ; Virulence Factors ; }, abstract = {BACKGROUND: The opportunistic pathogens Fusobacterium nucleatum and Porphyromonas gingivalis are Gram-negative bacteria associated with oral biofilm and periodontal disease. This study investigated interactions between F. nucleatum and P. gingivalis proteomes with the objective to identify proteins relevant in biofilm formation.

METHODS: We applied liquid chromatography-tandem mass spectrometry to determine the expressed proteome of F. nucleatum and P. gingivalis cells grown in biofilm or planktonic culture, and as mono- and dual-species models. The detected proteins were classified into functional categories and their label-free quantitative (LFQ) intensities statistically compared.

RESULTS: The proteomic analyses detected 1,322 F. nucleatum and 966 P. gingivalis proteins, including abundant virulence factors. Using univariate statistics, we identified significant changes between biofilm and planktonic culture (p-value ≤0.05) in 0,4% F. nucleatum, 7% P. gingivalis, and 14% of all proteins in the dual-species model. For both species, proteins involved in vitamin B2 (riboflavin) metabolism had significantly increased levels in biofilm. In both mono- and dual-species biofilms, P. gingivalis increased the production of proteins for translation, oxidation-reduction, and amino acid metabolism compared to planktonic cultures. However, when we compared LFQ intensities between mono- and dual-species, over 90% of the significantly changed P. gingivalis proteins had their levels reduced in biofilm and planktonic settings of the dual-species model.

CONCLUSIONS: The findings suggest that P. gingivalis reduces the production of multiple proteins because of the F. nucleatum presence. The results highlight the complex interactions of bacteria contributing to oral biofilms, which need to be considered in the design of prevention strategies.}, } @article {pmid34543106, year = {2021}, author = {Thai, SN and Lum, MR and Naegle, J and Onofre, M and Abdulla, H and Garcia, A and Fiterz, A and Arnell, A and Lwin, TT and Kavanaugh, A and Hikmat, Z and Garabedian, N and Ngo, RT and Dimaya, B and Escamilla, A and Barseghyan, L and Shibatsuji, M and Soltani, S and Butcher, L and Hikmat, F and Amirian, D and Bazikyan, A and Brandt, N and Sarkisian, M and Munoz, X and Ovakimyan, A and Burnett, E and Pham, JN and Shirvanian, A and Hernandez, R and Vardapetyan, M and Wada, M and Ramirez, C and Zakarian, M and Billi, F}, title = {Multiple Copies of flhDC in Paraburkholderia unamae Regulate Flagellar Gene Expression, Motility, and Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {203}, number = {23}, pages = {e0029321}, pmid = {34543106}, issn = {1098-5530}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/growth & development ; Burkholderiaceae/genetics/*metabolism ; Flagella/genetics/*metabolism ; Gene Dosage ; Gene Expression Regulation, Bacterial/*physiology ; Movement/*physiology ; Trans-Activators/genetics/*metabolism ; }, abstract = {FlhDC is a heterohexameric complex that acts as a master regulator of flagellar biosynthesis genes in numerous bacteria. Previous studies have identified a single flhDC operon encoding this complex. However, we found that two flhDC loci are present throughout Paraburkholderia, and two additional flhC copies are also present in Paraburkholderia unamae. Systematic deletion analysis in P. unamae of the different flhDC copies showed that one of the operons, flhDC1, plays the predominant role, with deletion of its genes resulting in a severe inhibition of motility and biofilm formation. Expression analysis using promoter-lacZ fusions and real-time quantitative PCR support the primary role of flhDC1 in flagellar gene regulation, with flhDC2 a secondary contributor. Phylogenetic analysis shows the presence of the flhDC1 and flhDC2 operons throughout Paraburkholderia. In contrast, Burkholderia and other bacteria only carry the copy syntenous with flhDC2. The variations in impact each copy of flhDC has on downstream processes indicate that regulation of FlhDC in P. unamae, and likely other Paraburkholderia species, is regulated at least in part by the presence of multiple copies of these genes. IMPORTANCE Motility is important in the colonization of plant roots by beneficial and pathogenic bacteria, with flagella playing essential roles in host cell adhesion, entrance, and biofilm formation. Flagellar biosynthesis is energetically expensive. Its complex regulation by the FlhDC master regulator is well studied in peritrichous flagella expressing enterics. We report the unique presence throughout Paraburkholderia of multiple copies of flhDC. In P. unamae, the flhDC1 copy showed higher expression and a greater effect on swim motility, flagellar development, and regulation of downstream genes, than the flhDC2 copy that is syntenous to flhDC in Escherichia coli and pathogenic Burkholderia spp. The flhDC genes have evolved differently in these plant-growth-promoting bacteria, giving an additional layer of complexity in gene regulation by FlhDC.}, } @article {pmid34540932, year = {2021}, author = {Santos, LM and Rodrigues, DM and Kalil, MA and Azevedo, V and Meyer, R and Umsza-Guez, MA and Machado, BA and Seyffert, N and Portela, RW}, title = {Activity of Ethanolic and Supercritical Propolis Extracts in Corynebacterium pseudotuberculosis and Its Associated Biofilm.}, journal = {Frontiers in veterinary science}, volume = {8}, number = {}, pages = {700030}, pmid = {34540932}, issn = {2297-1769}, abstract = {Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis in small ruminants, a chronic disease characterized by the development of granulomas in superficial and visceral lymph nodes as well as in several organs. An important characteristic of the infection with this bacterium is the formation of a biofilm and the absence of effective antibiotic therapy against the disease. From this scenario, the objective of this study was to evaluate the susceptibility of C. pseudotuberculosis to conventional antibiotics and to red, green, and brown propolis extracts obtained by the supercritical and ethanolic extraction methods as well as its activity in the bacterial biofilm. The results of the sensitivity test using antibiotics indicated a sensitivity of C. pseudotuberculosis strains to the antimicrobial agents. The ethanolic extract of green propolis and the supercritical red propolis extract showed the best antibacterial activities against planktonic C. pseudotuberculosis. A lower antimicrobial activity of the brown propolis extract was identified. Propolis extracts were effective in interfering with the formation of the C. pseudotuberculosis biofilm but had little activity on the consolidated biofilm. In conclusion, propolis extracts are more effective against C. pseudotuberculosis in the planktonic stage, being able to interfere with the formation of bacterial biofilm. However, the action of propolis extracts in a sessile and structured microbial biofilm is reduced.}, } @article {pmid34539591, year = {2021}, author = {Eckroat, TJ and Greguske, C and Hunnicutt, DW}, title = {The Type 9 Secretion System Is Required for Flavobacterium johnsoniae Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {660887}, pmid = {34539591}, issn = {1664-302X}, abstract = {Flavobacterium johnsoniae forms biofilms in low nutrient conditions. Protein secretion and cell motility may have roles in biofilm formation. The F. johnsoniae type IX secretion system (T9SS) is important for both secretion and motility. To determine the roles of each process in biofilm formation, mutants defective in secretion, in motility, or in both processes were tested for their effects on biofilm production using a crystal violet microplate assay. All mutants that lacked both motility and T9SS-mediated secretion failed to produce biofilms. A porV deletion mutant, which was severely defective for secretion, but was competent for motility, also produced negligible biofilm. In contrast, mutants that retained secretion but had defects in gliding formed biofilms. An sprB mutant that is severely but incompletely defective in gliding motility but retains a fully functional T9SS was similar to the wild type in biofilm formation. Mutants with truncations of the gldJ gene that compromise motility but not secretion showed partial reduction in biofilm formation compared to wild type. Unlike the sprB mutant, these gldJ truncation mutants were essentially nonmotile. The results show that a functional T9SS is required for biofilm formation. Gliding motility, while not required for biofilm formation, also appears to contribute to formation of a robust biofilm.}, } @article {pmid34537868, year = {2021}, author = {Ishvaria, S and Dharshini, RS and Manickam, R and Pooja, KR and Ramya, M}, title = {Draft genome sequencing and functional annotation and characterization of biofilm-producing bacterium Bacillus novalis PD1 isolated from rhizospheric soil.}, journal = {Antonie van Leeuwenhoek}, volume = {114}, number = {12}, pages = {1977-1989}, pmid = {34537868}, issn = {1572-9699}, mesh = {*Bacillus/genetics ; Biofilms ; DNA, Bacterial ; Phylogeny ; RNA, Ribosomal, 16S ; *Soil ; }, abstract = {Biofilm forming bacterium Bacillus novalis PD1 was isolated from the rhizospheric soil of a paddy field. B. novalis PD1 is a Gram-positive, facultatively anaerobic, motile, slightly curved, round-ended, and spore-forming bacteria. The isolate B. novalis PD1 shares 98.45% similarity with B. novalis KB27B. B. vireti LMG21834 and B. drentensis NBRC 102,427 are the closest phylogenetic neighbours for B. novalis PD1. The draft genome RAST annotation showed a linear chromosome with 4,569,088 bp, encoding 6139 coding sequences, 70 transfer RNA (tRNA), and 11 ribosomal RNA (rRNA) genes. The genomic annotation of biofilm forming B. novalis PD1(> 3.6@OD595nm) showed the presence of exopolysaccharide-forming genes (ALG, PSL, and PEL) as well as other biofilm-related genes (comER, Spo0A, codY, sinR, TasA, sipW, degS, and degU). Antibiotic inactivation gene clusters (ANT (6)-I, APH (3')-I, CatA15/A16 family), efflux pumps conferring antibiotic resistance genes (BceA, BceB, MdtABC-OMF, MdtABC-TolC, and MexCD-OprJ), and secondary metabolites linked to phenazine, terpene, and beta lactone gene clusters are part of the genome.}, } @article {pmid34534802, year = {2022}, author = {Miao, L and Guo, S and Wu, J and Adyel, TM and Liu, Z and Liu, S and Hou, J}, title = {Polystyrene nanoplastics change the functional traits of biofilm communities in freshwater environment revealed by GeoChip 5.0.}, journal = {Journal of hazardous materials}, volume = {423}, number = {Pt B}, pages = {127117}, doi = {10.1016/j.jhazmat.2021.127117}, pmid = {34534802}, issn = {1873-3336}, mesh = {Biofilms ; Ecosystem ; Fresh Water ; Microplastics ; *Nanoparticles ; Polystyrenes ; *Water Pollutants, Chemical/toxicity ; }, abstract = {There is an increasing concern regarding the potential effects of nanoplastics (NPs) on freshwater ecosystems. Considering the functional values of biofilms in freshwater, knowledge on whether and to what extent NPs can influence the ecosystem processes of biofilms were still limited. Herein, the freshwater biofilms cultured in lab were exposed to 100 nm polystyrene NPs (PS-NPs) of different dosages (1 and 10 mg/L) for 14 days. Confocal laser scanning microscope observation indicated that biofilms were dominated by filamentous, and spiral algae species and the intensity of extracellular polymeric substances increased under PS-NPs exposure. GeoChip 5.0 analysis revealed that PS-NPs exposure triggered a significant increase in functional genes α diversity (p < 0.05) and altered biofilms' functional structure. Furthermore, the abundance of genes involved in the total carbon and nitrogen cycling were increased under PS-NPs exposure. The abundance of nitrogen fixation genes experienced the most pronounced increase (24.4%) under 1 mg/L PS-NPs treatment, consistent with the increase of ammonium in overlying water. Whereas antibiotic resistance genes and those related to photosynthetic pigments production were suppressed. These results provided direct evidence for PS-NPs' effects on the biofilm functions in terms of biogeochemical cycling, improving our understanding of the potentials of NPs on freshwater ecosystems.}, } @article {pmid34531666, year = {2021}, author = {Gedefie, A and Demsis, W and Ashagrie, M and Kassa, Y and Tesfaye, M and Tilahun, M and Bisetegn, H and Sahle, Z}, title = {Acinetobacter baumannii Biofilm Formation and Its Role in Disease Pathogenesis: A Review.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {3711-3719}, pmid = {34531666}, issn = {1178-6973}, abstract = {Acinetobacter species, particularly Acinetobacter baumannii, is the first pathogen on the critical priority list of pathogens for novel antibiotics to become a "red-alert" human pathogen. Acinetobacter baumannii is an emerging global antibiotic-resistant gram-negative bacteria that most typically causes biofilm-associated infections such as ventilator-associated pneumonia and catheter-related infection, both of which are resistant to antibiotic therapy. A. baumannii's capacity to develop antibiotic resistance mechanisms allows the organism to thrive in hospital settings, facilitating the global spread of multidrug-resistant strains. Although Acinetobacter infections are quickly expanding throughout hospital environments around the world, the highest concentration of infections occurs in intensive care units (ICUs). Biofilms are populations of bacteria on biotic or abiotic surfaces that are encased in the extracellular matrix and play a crucial role in pathogenesis, making treatment options more difficult. Even though a variety of biological and environmental elements are involved in the production of A. baumannii biofilms, glucose is the most important component. Biofilm-mediated A. baumannii infections are the most common type of A. baumannii infection associated with medical equipment, and they are extremely difficult to treat. As a result, health care workers (HCWs) should focus on infection prevention and safety actions to avoid A. baumannii biofilm-related infections caused by medical devices, and they should be very selective when using treatments in combination with anti-biofilms. Therefore, this review discusses biofilm formation in A. baumannii, its role in disease pathogenesis, and its antimicrobial resistance mechanism.}, } @article {pmid34530240, year = {2021}, author = {Liu, C and Yan, H and Sun, Y and Chen, B}, title = {Contribution of enrofloxacin and Cu[2+] to the antibiotic resistance of bacterial community in a river biofilm.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {291}, number = {}, pages = {118156}, doi = {10.1016/j.envpol.2021.118156}, pmid = {34530240}, issn = {1873-6424}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial/genetics ; Enrofloxacin ; Genes, Bacterial ; *Metals, Heavy ; *Rivers ; }, abstract = {Pollutants discharged from wastewater are the main cause of the spread of antibiotic resistance in river biofilms. There is controversy regarding the primary contribution of environmental selectors such as antibiotics and heavy metals to the development of antibiotic resistance in bacterial communities. Here, this study compared the effect of environmental safety concentration Cu[2+] and enrofloxacin (ENR) on the evolution of antibiotic resistance by examining phenotypic characteristics and genotypic profiles of bacterial communities in a river biofilm, and then distinguished the major determinants from a comprehensive perspective. The pollution induced community tolerance in ENR-treated group was significantly higher than that in Cu[2+]-treated group (at concentration levels of 100 and 1000 μg/L). Metagenomic sequencing results showed that ENR significantly increased the number and total abundance of antibiotic resistance genes (ARGs), but there was no significant change in the Cu[2+]- treated group. Compared with Cu[2+], ENR was the major selective agent in driving the change of taxonomic composition because the taxonomic composition in ENR was the most different from the original biofilm. Comparing and analyzing the prokaryotic composition, the phylum of Proteobacteria was enriched in both ENR and Cu[2+] treated groups. Among them, Acidovorax and Bosea showed resistance to both pollutants. Linking taxonomic composition to ARGs revealed that the main potential hosts of fluoroquinolone resistance genes were Comamonas, Sphingopyxis, Bradyrhizobium, Afipia, Rhodopseudomonas, Luteimonas and Hoeflea. The co-occurrence of ARGs and metal resistance genes (MRGs) showed that the multidrug efflux pump was the key mechanism connecting MRGs and ARGs. Network analysis also revealed that the reason of Cu[2+] selected for fluoroquinolones resistant bacterial communities was the coexistence of multidrug efflux gene and MRGs. Our research emphasizes the importance of antibiotics in promoting the development of antibiotic resistant bacterial communities from the perspective of changes in community structure and resistome in river biofilms.}, } @article {pmid34530014, year = {2021}, author = {Kasza, K and Gurnani, P and Hardie, KR and Cámara, M and Alexander, C}, title = {Challenges and solutions in polymer drug delivery for bacterial biofilm treatment: A tissue-by-tissue account.}, journal = {Advanced drug delivery reviews}, volume = {178}, number = {}, pages = {113973}, doi = {10.1016/j.addr.2021.113973}, pmid = {34530014}, issn = {1872-8294}, support = {BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; /DH_/Department of Health/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy/microbiology ; Biofilms/drug effects ; *Drug Delivery Systems ; Humans ; Polymers/chemistry/*pharmacology ; }, abstract = {To tackle the emerging antibiotic resistance crisis, novel antimicrobial approaches are urgently needed. Bacterial communities (biofilms) are a particular concern in this context. Biofilms are responsible for most human infections and are inherently less susceptible to antibiotic treatments. Biofilms have been linked with several challenging chronic diseases, including implant-associated osteomyelitis and chronic wounds. The specific local environments present in the infected tissues further contribute to the rise in antibiotic resistance by limiting the efficacy of systemic antibiotic therapies and reducing drug concentrations at the infection site, which can lead to reoccurring infections. To overcome the shortcomings of systemic drug delivery, encapsulation within polymeric carriers has been shown to enhance antimicrobial efficacy, permeation and retention at the infection site. In this Review, we present an overview of current strategies for antimicrobial encapsulation within polymeric carriers, comparing challenges and solutions on a tissue-by-tissue basis. We compare challenges and proposed drug delivery solutions from the perspective of the local environments for biofilms found in oral, wound, gastric, urinary tract, bone, pulmonary, vaginal, ocular and middle/inner ear tissues. We will also discuss future challenges and barriers to clinical translation for these therapeutics. The following Review demonstrates there is a significant imbalance between the research focus being placed on different tissue types, with some targets (oral and wound biofims) being extensively more studied than others (vaginal and otitis media biofilms and endocarditis). Furthermore, the importance of the local tissue environment when selecting target therapies is demonstrated, with some materials being optimal choices for certain sites of bacterial infection, while having limited applicability in others.}, } @article {pmid34529974, year = {2021}, author = {Ryan Kaler, KM and Nix, JC and Schubot, FD}, title = {RetS inhibits Pseudomonas aeruginosa biofilm formation by disrupting the canonical histidine kinase dimerization interface of GacS.}, journal = {The Journal of biological chemistry}, volume = {297}, number = {4}, pages = {101193}, pmid = {34529974}, issn = {1083-351X}, support = {P30 GM124169/GM/NIGMS NIH HHS/United States ; R21 AI128255/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Histidine Kinase/genetics/*metabolism ; Phosphorylation ; *Protein Multimerization ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Bacterial signaling histidine kinases (HKs) have long been postulated to function exclusively through linear signal transduction chains. However, several HKs have recently been shown to form complex multikinase networks (MKNs). The most prominent MKN, involving the enzymes RetS and GacS, controls the switch between the motile and biofilm lifestyles in the pathogenic bacterium Pseudomonas aeruginosa. While GacS promotes biofilm formation, RetS counteracts GacS using three distinct mechanisms. Two are dephosphorylating mechanisms. The third, a direct binding between the RetS and GacS HK regions, blocks GacS autophosphorylation. Focusing on the third mechanism, we determined the crystal structure of a cocomplex between the HK region of RetS and the dimerization and histidine phosphotransfer (DHp) domain of GacS. This is the first reported structure of a complex between two distinct bacterial signaling HKs. In the complex, the canonical HK homodimerization interface is replaced by a strikingly similar heterodimeric interface between RetS and GacS. We further demonstrate that GacS autophosphorylates in trans, thus explaining why the formation of a RetS-GacS complex inhibits GacS autophosphorylation. Using mutational analysis in conjunction with bacterial two-hybrid and biofilm assays, we not only corroborate the biological role of the observed RetS-GacS interactions, but also identify a residue critical for the equilibrium between the RetS-GacS complex and the respective RetS and GacS homodimers. Collectively, our findings suggest that RetS and GacS form a domain-swapped hetero-oligomer during the planktonic growth phase of P. aeruginosa before unknown signals cause its dissociation and a relief of GacS inhibition to promote biofilm formation.}, } @article {pmid34529734, year = {2021}, author = {Yu, Y and Kim, YH and Cho, WH and Son, BS and Yeo, HJ}, title = {Biofilm microbiome in extracorporeal membrane oxygenator catheters.}, journal = {PloS one}, volume = {16}, number = {9}, pages = {e0257449}, pmid = {34529734}, issn = {1932-6203}, mesh = {Arthrobacter/genetics/isolation & purification/physiology ; Bacteremia/*microbiology/pathology ; Bacteria/genetics/isolation & purification ; Biofilms ; Catheter-Related Infections/*microbiology/pathology ; Extracorporeal Membrane Oxygenation/*instrumentation ; Female ; Humans ; Male ; *Microbiota ; Middle Aged ; Neisseria/genetics/isolation & purification/physiology ; RNA, Ribosomal, 16S/analysis/genetics/metabolism ; Retrospective Studies ; }, abstract = {Despite the formation of biofilms on catheters for extracorporeal membrane oxygenation (ECMO), some patients do not show bacteremia. To elucidate the specific linkage between biofilms and bacteremia in patients with ECMO, an improved understanding of the microbial community within catheter biofilms is necessary. Hence, we aimed to evaluate the biofilm microbiome of ECMO catheters from adults with (n = 6) and without (n = 15) bacteremia. The microbiomes of the catheter biofilms were evaluated by profiling the V3 and V4 regions of bacterial 16s rRNA genes using the Illumina MiSeq sequencing platform. In total, 2,548,172 reads, with an average of 121,341 reads per sample, were generated. Although alpha diversity was slightly higher in the non-bacteremic group, the difference was not statistically significant. In addition, there was no difference in beta diversity between the two groups. We found 367 different genera, of which 8 were present in all samples regardless of group; Limnohabitans, Flavobacterium, Delftia, Massilia, Bacillus, Candidatus, Xiphinematobacter, and CL0-1 showed an abundance of more than 1% in the sample. In particular, Arthrobacter, SMB53, Neisseria, Ortrobactrum, Candidatus Rhabdochlamydia, Deefgae, Dyella, Paracoccus, and Pedobacter were highly abundant in the bacteremic group. Network analysis indicated that the microbiome of the bacteremic group was more complex than that of the non-bacteremic group. Flavobacterium and CL0.1, which were abundant in the bacteremic group, were considered important genera because they connected different subnetworks. Biofilm characteristics in ECMO catheters varied according to the presence or absence of bacteremia. There were no significant differences in diversity between the two groups, but there were significant differences in the community composition of the biofilms. The biofilm-associated community was dynamic, with the bacteremic group showing very complex network connections within the microbiome.}, } @article {pmid34529329, year = {2022}, author = {Moradi, M and Fazlyab, M and Pourhajibagher, M and Chiniforush, N}, title = {Antimicrobial action of photodynamic therapy on Enterococcus faecalis biofilm using curing light, curcumin and riboflavin.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {48}, number = {2}, pages = {274-282}, doi = {10.1111/aej.12565}, pmid = {34529329}, issn = {1747-4477}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; *Curcumin/pharmacology/therapeutic use ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; *Photochemotherapy/methods ; Riboflavin/pharmacology ; Root Canal Irrigants/pharmacology/therapeutic use ; Sodium Hypochlorite/pharmacology ; }, abstract = {The aim of this study was to assess the effect of antimicrobial photodynamic therapy (aPDT) with curcumin and riboflavin on three-week Enterococcus faecalis biofilm. At first the 15-mm root canals of 65 single rooted extracted human teeth (including maxillary incisors, mandibular and maxillary canines and mandibular premolars) were separated from the crown and were prepared with ProTaper instruments. After autoclave sterilisation, samples were inoculated with E. faecalis suspension, and incubated for three weeks. After ensuring biofilm formation by scanning electron microscopy (SEM) in two teeth, the remaining 63 teeth were randomly divided into seven groups (n = 9): aPDT + curcumin, aPDT + riboflavin, LED, curcumin, riboflavin, 5.25% NaOCl (positive control) and no intervention (negative control). For light source a LED unit with 390-480 nm wavelength (peak of 460 nm), power density of 1000 ± 100 mW cm[-2] and mean energy density of 60 J cm[-2] was used. The roots were horizontally sectioned into coronal, middle and apical thirds each with 5 mm thicknesses. Dentin chips with equal weight (1 ± 0.005 g) were collected from the root canal walls with Gates Glidden drills and were transferred into microtubes containing 1 mL of sterile saline and vortexed for 30 s. Next, 10 µL of the contents of each tube was serially diluted and eventually, 10 µL of each solution was cultured on BHI agar. The number of colony-forming units was determined. Data were analysed using the Kruskal-Wallis and Friedman tests. The colony reduction was not significantly different between NaOCl and either riboflavin + LED or Curcumin + LED. The 5.25% NaOCl group showed maximum reduction in colony count, compared with the negative control (P = 0.00). Groups with aPDT with Curcumin + LED (P = 0.005), and with riboflavin + LED (P = 0.011) showed significant reduction in colony count in all three canal thirds (P < 0.05) without any difference with one another. With significant reduction of E. faecalis colony count, aPDT with Curcumin and riboflavin can serve as an adjunct to routine root canal disinfection method.}, } @article {pmid34528354, year = {2021}, author = {Urvoy, M and Lami, R and Dreanno, C and Daudé, D and Rodrigues, AMS and Gourmelon, M and L'Helguen, S and Labry, C}, title = {Quorum sensing disruption regulates hydrolytic enzyme and biofilm production in estuarine bacteria.}, journal = {Environmental microbiology}, volume = {23}, number = {11}, pages = {7183-7200}, doi = {10.1111/1462-2920.15775}, pmid = {34528354}, issn = {1462-2920}, mesh = {Acyl-Butyrolactones ; Biofilms ; Ecosystem ; *Quorum Sensing/genetics ; *Vibrio ; }, abstract = {Biofilms of heterotrophic bacteria cover organic matter aggregates and constitute hotspots of mineralization, primarily acting through extracellular hydrolytic enzyme production. Nevertheless, regulation of both biofilm and hydrolytic enzyme synthesis remains poorly investigated, especially in estuarine ecosystems. In this study, various bioassays, mass spectrometry and genomics approaches were combined to test the possible involvement of quorum sensing (QS) in these mechanisms. QS is a bacterial cell-cell communication system that relies notably on the emission of N-acylhomoserine lactones (AHLs). In our estuarine bacterial collection, we found that 28 strains (9%), mainly Vibrio, Pseudomonas and Acinetobacter isolates, produced at least 14 different types of AHLs encoded by various luxI genes. We then inhibited the AHL QS circuits of those 28 strains using a broad-spectrum lactonase preparation and tested whether biofilm production as well as β-glucosidase and leucine-aminopeptidase activities were impacted. Interestingly, we recorded contrasted responses, as biofilm production, dissolved and cell-bound β-glucosidase and leucine-aminopeptidase activities significantly increased in 4%-68% of strains but decreased in 0%-21% of strains. These findings highlight the key role of AHL-based QS in estuarine bacterial physiology and ultimately on biogeochemical cycles. They also point out the complexity of QS regulations within natural microbial assemblages.}, } @article {pmid34526981, year = {2021}, author = {Abdul Hamid, AI and Cara, A and Diot, A and Laurent, F and Josse, J and Gueirard, P}, title = {Differential Early in vivo Dynamics and Functionality of Recruited Polymorphonuclear Neutrophils After Infection by Planktonic or Biofilm Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {728429}, pmid = {34526981}, issn = {1664-302X}, abstract = {Staphylococcus aureus is a human pathogen known for its capacity to shift between the planktonic and biofilm lifestyles. In vivo, the antimicrobial immune response is characterized by the recruitment of inflammatory phagocytes, namely polymorphonuclear neutrophils (PMNs) and monocytes/macrophages. Immune responses to planktonic bacteria have been extensively studied, but many questions remain about how biofilms can modulate inflammatory responses and cause recurrent infections in live vertebrates. Thus, the use of biologically sound experimental models is essential to study the specific immune signatures elicited by biofilms. Here, a mouse ear pinna model of infection was used to compare early innate immune responses toward S. aureus planktonic or biofilm bacteria. Flow cytometry and cytokine assays were carried out to study the inflammatory responses in infected tissues. These data were complemented with intravital confocal imaging analyses, allowing the real-time observation of the dynamic interactions between EGFP + phagocytes and bacteria in the ear pinna tissue of LysM-EGFP transgenic mice. Both bacterial forms induced an early and considerable recruitment of phagocytes in the ear tissue, associated with a predominantly pro-inflammatory cytokine profile. The inflammatory response was mostly composed of PMNs in the skin and the auricular lymph node. However, the kinetics of PMN recruitment were different between the 2 forms in the first 2 days post-infection (pi). Two hours pi, biofilm inocula recruited more PMNs than planktonic bacteria, but with decreased motility parameters and capacity to emit pseudopods. Inversely, biofilm inocula recruited less PMNs 2 days pi, but with an "over-activated" status, illustrated by an increased phagocytic activity, CD11b level of expression and ROS production. Thus, the mouse ear pinna model allowed us to reveal specific differences in the dynamics of recruitment and functional properties of phagocytes against biofilms. These differences would influence the specific adaptive immune responses to biofilms elicited in the lymphoid tissues.}, } @article {pmid34526980, year = {2021}, author = {Prados, MB and Lescano, M and Porzionato, N and Curutchet, G}, title = {Wiring Up Along Electrodes for Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {726251}, pmid = {34526980}, issn = {1664-302X}, abstract = {Millimeter-length cables of bacteria were discovered growing along a graphite-rod electrode serving as an anode of a microbial electrolysis cell (MEC). The MEC had been inoculated with a culture of Fe-reducing microorganisms enriched from a polluted river sediment (Reconquista river, Argentina) and was operated at laboratory controlled conditions for 18 days at an anode poised potential of 240 mV (vs. Ag/AgCl), followed by 23 days at 480 mV (vs. Ag/AgCl). Anode samples were collected for scanning electron microscopy, phylogenetic and electrochemical analyses. The cables were composed of a succession of bacteria covered by a membranous sheath and were distinct from the known "cable-bacteria" (family Desulfobulbaceae). Apparently, the formation of the cables began with the interaction of the cells via nanotubes mostly located at the cell poles. The cables seemed to be further widened by the fusion between them. 16S rRNA gene sequence analysis confirmed the presence of a microbial community composed of six genera, including Shewanella, a well-characterized electrogenic bacteria. The formation of the cables might be a way of colonizing a polarized surface, as determined by the observation of electrodes extracted at different times of MEC operation. Since the cables of bacteria were distinct from any previously described, the results suggest that bacteria capable of forming cables are more diverse in nature than already thought. This diversity might render different electrical properties that could be exploited for various applications.}, } @article {pmid34525984, year = {2021}, author = {Schneider-Rayman, M and Steinberg, D and Sionov, RV and Friedman, M and Shalish, M}, title = {Effect of epigallocatechin gallate on dental biofilm of Streptococcus mutans: An in vitro study.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {447}, pmid = {34525984}, issn = {1472-6831}, mesh = {Biofilms ; *Catechin/analogs & derivatives/pharmacology ; *Dental Caries ; Humans ; Streptococcus mutans/genetics ; }, abstract = {BACKGROUND: Streptococcus mutans (S. mutans) plays a major role in the formation of dental caries. The aim of this study was to examine the effect of the green tea polyphenol, epigallocatechin gallate (EGCG), on biofilm formation of S. mutans.

METHODS: Following exposure to increasing concentrations of EGCG, the planktonic growth was measured by optical density and the biofilm biomass was quantified by crystal violet staining. Exopolysaccharides (EPS) production was visualized by confocal scanning laser microscopy, and the bacterial DNA content was determined by quantitative polymerase chain reaction (qPCR). Gene expression of selected genes was analyzed by real time (RT)-qPCR and membrane potential was examined by flow cytometry.

RESULTS: We observed that EGCG inhibited in a dose-dependent manner both the planktonic growth and the biofilm formation of S. mutans. Significant reduction of S. mutans biofilm formation, DNA content, and EPS production was observed at 2.2-4.4 mg/ml EGCG. EGCG reduced the expression of gtfB, gtfC and ftf genes involved in EPS production, and the nox and sodA genes involved in the protection against oxidative stress. Moreover, EGCG caused an immediate change in membrane potential.

CONCLUSIONS: EGCG, a natural polyphenol, has a significant inhibitory effect on S. mutans dental biofilm formation and EPS production, and thus might be a potential drug in preventing dental caries.}, } @article {pmid34525167, year = {2021}, author = {Rivas, DP and Hedgecock, ND and Stebe, KJ and Leheny, RL}, title = {Dynamic and mechanical evolution of an oil-water interface during bacterial biofilm formation.}, journal = {Soft matter}, volume = {17}, number = {35}, pages = {8195-8210}, doi = {10.1039/d1sm00795e}, pmid = {34525167}, issn = {1744-6848}, mesh = {Bacteria ; *Biofilms ; Pseudomonas aeruginosa ; Rheology ; *Water ; }, abstract = {We present an experimental study combining particle tracking, active microrheology, and differential dynamic microscopy (DDM) to investigate the dynamics and rheology of an oil-water interface during biofilm formation by the bacteria Pseudomonas Aeruginosa PA14. The interface transitions from an active fluid dominated by the swimming motion of adsorbed bacteria at early age to an active viscoelastic system at late ages when the biofilm is established. The microrheology measurements using microscale magnetic rods indicate that the biofilm behaves as a viscoelastic solid at late age. The bacteria motility at the interface during the biofilm formation, which is characterized in the DDM measurements, evolves from diffusive motion at early age to constrained, quasi-localized motion at later age. Similarly, the mobility of passively moving colloidal spheres at the interface decreases significantly with increasing interface age and shows a dependence on sphere size after biofilm formation that is orders-of-magnitude larger than that expected in a homogeneous system in equilibrium. We attribute this anomalous size dependence to either length-scale-dependent rheology of the biofilm or widely differing effects of the bacteria activity on the motion of spheres of different sizes.}, } @article {pmid34524972, year = {2021}, author = {Gajdács, M and Kárpáti, K and Nagy, ÁL and Gugolya, M and Stájer, A and Burián, K}, title = {Association between biofilm-production and antibiotic resistance in Escherichia coli isolates: A laboratory-based case study and a literature review.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {}, number = {}, pages = {}, doi = {10.1556/030.2021.01487}, pmid = {34524972}, issn = {1588-2640}, abstract = {Bacteria can enhance their survival by attaching to inanimate surfaces or tissues, and presenting as multicellular communities encased in a protective extracellular matrix called biofilm. There has been pronounced interest in assessing the relationship between the antibiotic resistant phenotype and biofilm-production in clinically-relevant pathogens. The aim of the present paper was to provide additional experimental results on the topic, testing the biofilm-forming capacity of Escherichia coli isolates using in vitro methods in the context of their antibiotic resistance in the form of a laboratory case study, in addition to provide a comprehensive review of the subject. In our case study, a total of two hundred and fifty (n = 250) E. coli isolates, originating from either clean-catch urine samples (n = 125) or invasive samples (n = 125) were included. The colony morphology of isolates were recorded after 24h, while antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Biofilm-formation of the isolates was assessed with the crystal violet tube-adherence method. Altogether 57 isolates (22.8%) isolates were multidrug resistant (MDR), 89 isolates (35.6%) produced large colonies (>3 mm), mucoid variant colonies were produced in 131 cases (52.4%), and 108 (43.2%) were positive for biofilm formation. Biofilm-producers were less common among isolates resistant to third-generation cephalosporins and trimethoprim-sulfamethoxazole (P = 0.043 and P = 0.023, respectively). Biofilms facilitate a protective growth strategy in bacteria, ensuring safety against environmental stressors, components of the immune system and noxious chemical agents. Being an integral part of bacterial physiology, biofilm-formation is interdependent with the expression of other virulence factors (especially adhesins) and quorum sensing signal molecules. More research is required to allow for the full understanding of the interplay between the MDR phenotype and biofilm-production, which will facilitate the development of novel therapeutic strategies.}, } @article {pmid34524634, year = {2022}, author = {Liu, Z and Zhao, Z and Zeng, K and Xia, Y and Xu, W and Wang, R and Guo, J and Xie, H}, title = {Functional Immobilization of a Biofilm-Releasing Glycoside Hydrolase Dispersin B on Magnetic Nanoparticles.}, journal = {Applied biochemistry and biotechnology}, volume = {194}, number = {2}, pages = {737-747}, pmid = {34524634}, issn = {1559-0291}, support = {31771032//National Natural Science Foundation of China/ ; 51911530153//National Natural Science Foundation of China/ ; }, mesh = {*Silicon Dioxide ; }, abstract = {Dispersin B (DspB) is a member of glycoside hydrolase family 20 (GH20) and catalyzes degradation of biofilms forming by pathogenic bacteria such as Staphylococcus aureus. Magnetoreceptor (MagR) is a magnetic protein that can be used as a fusion partner for functionally immobilizing proteins on magnetic surfaces. In the present study, a recombinant protein DspB-MagR was constructed by fusing MagR to the C-terminus of DspB and expressed in Escherichia coli. Magnetic immobilization of purified DspB-MagR on magnetic core-shell structured Fe3O4@SiO2 nanoparticles was achieved and characterized by means of various techniques including SDS-PAGE, Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential measurement, and scanning electron microscopy. It was evaluated the influence of temperature, pH, and storage time on the performance of immobilized DspB-MagR on Fe3O4@SiO2 nanoparticles. Removal of biofilms forming by Staphylococcus aureus and other medical sourced bacterial species was achieved by using Fe3O4@SiO2 nanoparticles loading with DspB-MagR. This work promoted potential applications of DspB and similar enzymes for medical purposes.}, } @article {pmid34523997, year = {2021}, author = {Staats, A and Burback, PW and Eltobgy, M and Parker, DM and Amer, AO and Wozniak, DJ and Wang, SH and Stevenson, KB and Urish, KL and Stoodley, P}, title = {Synovial Fluid-Induced Aggregation Occurs across Staphylococcus aureus Clinical Isolates and is Mechanistically Independent of Attached Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {9}, number = {2}, pages = {e0026721}, pmid = {34523997}, issn = {2165-0497}, support = {K08 AR071494/AR/NIAMS NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; R03 AR077602/AR/NIAMS NIH HHS/United States ; R01 HL127651/HL/NHLBI NIH HHS/United States ; R01 AI124121/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Cattle ; Hip Prosthesis/microbiology ; Humans ; Knee Prosthesis/microbiology ; Prosthesis-Related Infections/*microbiology ; Serum/microbiology ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects/*growth & development/isolation & purification ; Synovial Fluid/*microbiology ; Synovial Membrane/microbiology ; }, abstract = {Rapid synovial fluid-induced aggregation of Staphylococcus aureus is currently being investigated as an important factor in the establishment of periprosthetic joint infections (PJIs). Pathogenic advantages of aggregate formation have been well documented in vitro, including recalcitrance to antibiotics and protection from host immune defenses. The objective of the present work was to determine the strain dependency of synovial fluid-induced aggregation by measuring the degree of aggregation of 21 clinical S. aureus isolates cultured from either PJI or bloodstream infections using imaging and flow cytometry. Furthermore, by measuring attached bacterial biomass using a conventional crystal violet assay, we assessed whether there is a correlation between the aggregative phenotype and surface-associated biofilm formation. While all of the isolates were stimulated to aggregate upon exposure to bovine synovial fluid (BSF) and human serum (HS), the extent of aggregation was highly variable between individual strains. Interestingly, the PJI isolates aggregated significantly more upon BSF exposure than those isolated from bloodstream infections. While we were able to stimulate biofilm formation with all of the isolates in growth medium, supplementation with either synovial fluid or human serum inhibited bacterial surface attachment over a 24 h incubation. Surprisingly, there was no correlation between the degree of synovial fluid-induced aggregation and quantity of surface-associated biofilm as measured by a conventional biofilm assay without host fluid supplementation. Taken together, our findings suggest that synovial fluid-induced aggregation appears to be widespread among S. aureus strains and mechanistically independent of biofilm formation. IMPORTANCE Bacterial infections of hip and knee implants are rare but devastating complications of orthopedic surgery. Despite a widespread appreciation of the considerable financial, physical, and emotional burden associated with the development of a prosthetic joint infection, the establishment of bacteria in the synovial joint remains poorly understood. It has been shown that immediately upon exposure to synovial fluid, the viscous fluid in the joint, Staphylococcus aureus rapidly forms aggregates which are resistant to antibiotics and host immune cell clearance. The bacterial virulence associated with aggregate formation is likely a step in the establishment of prosthetic joint infection, and as such, it has the potential to be a potent target of prevention. We hope that this work contributes to the future development of therapeutics targeting synovial fluid-induced aggregation to better prevent and treat these infections.}, } @article {pmid34523579, year = {2021}, author = {Fung, AHY and Rao, S and Ngan, WY and Sekoai, PT and Touyon, L and Ho, TM and Wong, KP and Habimana, O}, title = {Exploring the optimization of aerobic food waste digestion efficiency through the engineering of functional biofilm Bio-carriers.}, journal = {Bioresource technology}, volume = {341}, number = {}, pages = {125869}, doi = {10.1016/j.biortech.2021.125869}, pmid = {34523579}, issn = {1873-2976}, mesh = {Biofilms ; Digestion ; *Food ; Microbial Consortia ; *Refuse Disposal ; }, abstract = {The possibility of breaking down cellulose-rich food waste through biofilm engineering was investigated. Six previously isolated strains from naturally degrading fruits and vegetables, screened for biofilm-forming ability and cellulolytic activity, were selected to enrich a biocarrier seeding microbial consortium. The food waste model used in this study was cabbage which was aerobically digested under repeated water rinsing and regular effluent drainage. The engineered biocarrier biofilm's functionality was evaluated by tracing microbial succession following metagenomic sequencing, quantitative PCR, scanning electron microscopy, and cellulolytic activity before and after the digestion processes. The engineered microbial consortium demonstrated superior biofilm-forming ability on biocarriers than the original microbial consortium and generally displayed a higher cellulolytic activity. The presented study provides one of the few studies of food waste aerobic digestion using engineered biofilms. Insights presented in this study could help further optimize aerobic food waste digestion.}, } @article {pmid34523551, year = {2021}, author = {Song, Z and Su, X and Li, P and Sun, F and Dong, W and Zhao, Z and Wen, Z and Liao, R}, title = {Facial fabricated biocompatible homogeneous biocarriers involving biochar to enhance denitrification performance in an anoxic moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {341}, number = {}, pages = {125866}, doi = {10.1016/j.biortech.2021.125866}, pmid = {34523551}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Charcoal ; *Denitrification ; Nitrogen/analysis ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Biochar prepared from pineapple peel was facially combined with polyurethane sponges for the first time to form homogeneous biocompatible biocarriers, which can enhance denitrification performance in an anoxic MBBR. The experiments showed that a higher NO3[-]-N removal efficiency (96.24 ± 1.3%) and kinetic constant (0.26 h[-1]) were obtained in the MBBR employing these new biocarriers (B-MBBR), compared with a control MBBR with polyurethane sponges (C-MBBR). The attached and suspended biomass of the B-MBBR was increased by 47% and 26%, respectively. Biochar significantly enhanced the abundance of functional bacteria in terms of promoting biofilm (i.e., Leptonema), denitrifying bacteria (i.e., Thauera, Enterobacter and Pseudomonas) and electroactive bacteria (i.e., Geobacter) in the B-MBBR. Meanwhile, based on the content of coenzyme I (NADH) and denitrifying enzymes, biochar would also enhance electron transport activity for denitrification. Consequently, these facial prepared biocarriers are effective to enhance denitrification performance in MBBR with application significance.}, } @article {pmid34523549, year = {2021}, author = {Huang, T and Zhao, J and Hu, B and Zhao, J and Yuan, C}, title = {Effective restoration of partial nitritation and anammox biofilm process by short-term hydroxylamine dosing: Mechanism and microbial interaction.}, journal = {Bioresource technology}, volume = {341}, number = {}, pages = {125910}, doi = {10.1016/j.biortech.2021.125910}, pmid = {34523549}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Biofilms ; *Bioreactors ; Hydroxylamine ; Hydroxylamines ; Microbial Interactions ; Nitrogen ; Oxidation-Reduction ; Wastewater ; }, abstract = {The one-stage partial nitritation and anammox (PN-A) process frequently experiences deterioration from ammonium accumulation and nitrate build-up. In this study, hydroxylamine was dosed to restore the process from deterioration in a continuously aerated PN-A sequencing biofilm batch reactor, and the impact of hydroxylamine on the metabolism of PN-A process was studied. PN-A process was totally restored in 5 days via 10 mg N·L[-1] hydroxylamine dosing, reducing nitrate-produced/ammonium-removed ratio from 28.5% to less than 11.0%. hydroxylamine dosing promoted biological production of nitric oxide and nitrous oxide and reduced the production of nitrate in the PN-A process. This study advanced the understanding of the metabolism versatility of hydroxylamine and nitric oxide as well as their function in interaction between aerobic ammonium oxidation bacteria and anaerobic ammonium oxidation bacteria, and proposed the potential application of hydroxylamine dosing in ammonium-contained wastewater treatment.}, } @article {pmid34522977, year = {2021}, author = {Sun, X and Xiang, J}, title = {Mechanism Underlying the Role of LuxR Family Transcriptional Regulator abaR in Biofilm Formation by Acinetobacter baumannii.}, journal = {Current microbiology}, volume = {78}, number = {11}, pages = {3936-3944}, pmid = {34522977}, issn = {1432-0991}, support = {16ZR1420800//Natural Science Foundation of Shanghai Municipal Science and Technology Commission/ ; }, mesh = {*Acinetobacter baumannii/genetics ; Biofilms ; Repressor Proteins/genetics/*physiology ; Trans-Activators/genetics/*physiology ; }, abstract = {Our study attempted to explore the mechanism underlying the role of LuxR family transcriptional regulator abaR in biofilm formation by Acinetobacter baumannii. The abaR gene was knocked out in ATCC 17978 strain using homologous recombination method. The growth curve and biofilm formation were measured in the wild type and abaR gene knockdown strains. Transcriptome sequencing was performed in the wild type and abaR gene knockdown strains following 8 h of culture. The growth curve in the abaR gene knockdown strain was similar to that of the wild-type strain. Biofilm formation significantly declined in the abaR gene knockdown strain at 8 and 48 h after culture. A total of 137 differentially expressed genes (DEGs) were obtained including 20 downregulated DEGs and 117 upregulated DEGs. Genes with differential expression were closely related to viral procapsid maturation (GO:0046797), acetoin catabolism (GO:0045150), carbon metabolism (ko01200), and the glycolysis/gluconeogenesis (ko00010)-related pathways. The results of the eight verified expression DEGs were consistent with the results predicted by bioinformatics. AbaR gene knockdown significantly affected biofilm formation by A. baumannii ATCC 17978 strain. The glycolysis/gluconeogenesis pathways were significantly dysregulated and induced by abaR gene knockdown in A. baumannii.}, } @article {pmid34522106, year = {2021}, author = {Yang, F and Liu, C and Ji, J and Cao, W and Ding, B and Xu, X}, title = {Molecular Characteristics, Antimicrobial Resistance, and Biofilm Formation of Pseudomonas aeruginosa Isolated from Patients with Aural Infections in Shanghai, China.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {3637-3645}, pmid = {34522106}, issn = {1178-6973}, abstract = {PURPOSE: To investigate molecular characteristics, antimicrobial resistance, and biofilm formation ability of Pseudomonas aeruginosa strains isolated from patients with aural infections.

METHODS: Isolates (n = 199) were collected from ear discharges of patients with aural infections from January 2019 to December 2020. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute guidelines. All isolates were subjected to multilocus sequence typing (MLST) with amplification and sequencing of seven housekeeping genes. Biofilm formation and eradication were quantitatively assessed in microtiter plates. Genes associated with biofilm formation and the quinolone-resistance-determining region (QRDR) of genes gyrA and parC were investigated using polymerase chain reaction amplification and sequencing.

RESULTS: Of the 199 P. aeruginosa strains isolated, 109 (54.77%) were from females and 90 (45.23%) were from males. The isolates exhibited very low rates of resistance to most antibiotics tested, including piperacillin (1.51%), ceftazidime (0.50%), and imipenem (3.52%); however, the quinolones ciprofloxacin (80.40%) and levofloxacin (82.91%) were notable exceptions. The QRDR sequence results of the quinolone-resistant P. aeruginosa isolates showed Thr83Ile (n = 155) was the most common amino acid mutation in gyrA (n = 165), while Ser87Leu (n = 157) was widely detected in parC (n = 165). MLST analysis identified 34 sequence types (STs) with most isolates belonging to ST316 (73.87%). Almost all of the P. aeruginosa isolates (96.98%) produced biofilms and biofilm-forming genes algD (98.49%), pslD (96.98%), and pelF (96.48%) were highly prevalent.

CONCLUSION: The P. aeruginosa strains isolated from aural discharges in this study exhibited very low rates of resistance to most antibiotics tested, except for the resistance rates to quinolones, which were relatively high. The isolates also exhibited a strong biofilm formation ability and low susceptibility to eradication, indicating that more effective drugs and treatment methods are needed to combat these infections.}, } @article {pmid34521475, year = {2021}, author = {Du, C and Huo, X and Gu, H and Wu, D and Hu, Y}, title = {Acid resistance system CadBA is implicated in acid tolerance and biofilm formation and is identified as a new virulence factor of Edwardsiella tarda.}, journal = {Veterinary research}, volume = {52}, number = {1}, pages = {117}, pmid = {34521475}, issn = {1297-9716}, support = {2019CXTD413//Natural Science Foundation of Hunan Province/ ; }, mesh = {Acids/metabolism ; *Biofilms ; Edwardsiella tarda/genetics/*pathogenicity/*physiology ; Virulence Factors/*genetics ; }, abstract = {Edwardsiella tarda is a facultative intracellular pathogen in humans and animals. The Gram-negative bacterium is widely considered a potentially important bacterial pathogen. Adaptation to acid stress is important for the transmission of intestinal microbes, so the acid-resistance (AR) system is essential. However, the AR systems of E. tarda are totally unknown. In this study, a lysine-dependent acid resistance (LDAR) system in E. tarda, CadBA, was characterized and identified. CadB is a membrane protein and shares high homology with the lysine/cadaverine antiporter. CadA contains a PLP-binding core domain and a pyridoxal phosphate-binding motif. It shares high homology with lysine decarboxylase. cadB and cadA are co-transcribed under one operon. To study the function of the cadBA operon, isogenic cadA, cadB and cadBA deletion mutant strains TX01ΔcadA, TX01ΔcadB and TX01ΔcadBA were constructed. When cultured under normal conditions, the wild type strain and three mutants exhibited the same growth performance. However, when cultured under acid conditions, the growth of three mutants, especially TX01ΔcadA, were obviously retarded, compared to the wild strain TX01, which indicates the important involvement of the cadBA operon in acid resistance. The deletion of cadB or cadA, especially cadBA, significantly attenuated bacterial activity of lysine decarboxylase, suggesting the vital participation of cadBA operon in lysine metabolism, which is closely related to acid resistance. The mutations of cadBA operon enhanced bacterial biofilm formation, especially under acid conditions. The deletions of the cadBA operon reduced bacterial adhesion and invasion to Hela cells. Consistently, the deficiency of cadBA operon abated bacterial survival and replication in macrophages, and decreased bacterial dissemination in fish tissues. Our results also show that the expression of cadBA operon and regulator cadC were up-regulated upon acid stress, and CadC rigorously regulated the expression of cadBA operon, especially under acid conditions. These findings demonstrate that the AR CadBA system was a requisite for the resistance of E. tarda against acid stress, and played a critical role in bacterial infection of host cells and in host tissues. This is the first study about the acid resistance system of E. tarda and provides new insights into the acid-resistance mechanism and pathogenesis of E. tarda.}, } @article {pmid34519903, year = {2021}, author = {Kijkla, P and Wang, D and Mohamed, ME and Saleh, MA and Kumseranee, S and Punpruk, S and Gu, T}, title = {Efficacy of glutaraldehyde enhancement by D-limonene in the mitigation of biocorrosion of carbon steel by an oilfield biofilm consortium.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {10}, pages = {174}, pmid = {34519903}, issn = {1573-0972}, mesh = {Bacteria/*drug effects/growth & development ; Biofilms/*drug effects ; Corrosion ; Disinfectants/*pharmacology ; Glutaral/*pharmacology ; Limonene/*pharmacology ; Oil and Gas Fields ; Seawater/microbiology ; Steel/*chemistry ; }, abstract = {Microbiologically influenced corrosion (MIC) is one of the major corrosion threats in the oil and gas industry. It is caused by environmental biofilms. Glutaraldehyde is a popular green biocide for mitigating biofilms and MIC. This work investigated the efficacy of glutaraldehyde enhancement by food-grade green chemical D-limonene in the biofilm prevention and MIC mitigation using a mixed-culture oilfield biofilm consortium. After 7 days of incubation at 37 °C in enriched artificial seawater in 125 mL anaerobic vials, the 100 ppm (w/w) glutaraldehyde + 200 ppm D-limonene combination treatment reduced the sessile cell counts on C1018 carbon steel coupons by 2.1-log, 1.7-log, and 2.3-log for sulfate reducing bacteria, acid producing bacteria, and general heterotrophic bacteria, respectively in comparison with the untreated control. The treatment achieved 68% weight loss reduction and 78% pit depth reduction. The 100 ppm glutaraldehyde + 200 ppm D-limonene combination treatment was found more effective in biofilm prevention and MIC mitigation than glutaraldehyde and D-limonene used individually. Electrochemical tests corroborated weight loss and pit depth data trends.}, } @article {pmid34519743, year = {2021}, author = {Fan, Q and Wang, C and Guo, R and Jiang, X and Li, W and Chen, X and Li, K and Hong, W}, title = {Step-by-step dual stimuli-responsive nanoparticles for efficient bacterial biofilm eradication.}, journal = {Biomaterials science}, volume = {9}, number = {20}, pages = {6889-6902}, doi = {10.1039/d1bm01038g}, pmid = {34519743}, issn = {2047-4849}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Azithromycin ; Bacteria ; *Biofilms ; Mice ; *Nanoparticles ; }, abstract = {Biofilm-related bacterial infections are extremely resistant to antibiotics, mainly due to the impermeability of the intensive matrices, which allow the bacteria to survive antibiotic treatment. Herein, step-by-step dual stimuli-responsive azithromycin-loaded nanoparticles (CM/AZM@Tyr) was constructed for efficient biofilm eradication. CM/AZM@Tyr was prepared by the self-assembly of poly(ε-caprolactone)-polyethylene glycol-polyethylenimine (PCL-PEG-PEI) into cationic micelles and simultaneously encapsulated AZM into the hydrophobic core, which is further bound with cis-aconityl-D-tyrosine (CA-Tyr) through electrostatic interaction. Upon initial penetration, CM/AZM@Tyr could show step-by-step dual-response to the microenvironment of biofilms. Firstly, the CA-Tyr shell rapidly responded to the acidic microenvironment and released D-Tyr to disassemble the biofilm mass. Then, the exposed cationic CM/AZM micelles could bind firmly to the negatively-charged bacteria cell membrane. With the enzymolysis of the PCL core, the rapidly releasing AZM could kill the bacteria over the depth of biofilms. Massive accumulation was observed in the infected lungs of biofilms-associated lung infection mice after the i.v. injection of CM/Cy5.5@Tyr under the 3D mode of the in vivo Imaging System. Reduced bacterial burden and alleviated fibrosis in the infected lungs were also obtained after treatment with CM/AZM@Tyr mainly due to its intensive penetration in the biofilm and the orderly release of the biofilm dispersant and antimicrobial agents. In summary, this research developed an effective strategy for the treatment of blood-accessible biofilm-induced infections.}, } @article {pmid34519474, year = {2021}, author = {Zou, Y and Lu, K and Lin, Y and Wu, Y and Wang, Y and Li, L and Huang, C and Zhang, Y and Brash, JL and Chen, H and Yu, Q}, title = {Dual-Functional Surfaces Based on an Antifouling Polymer and a Natural Antibiofilm Molecule: Prevention of Biofilm Formation without Using Biocides.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {38}, pages = {45191-45200}, doi = {10.1021/acsami.1c10747}, pmid = {34519474}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Biofouling/*prevention & control ; Boronic Acids/chemical synthesis/*chemistry ; Polyhydroxyethyl Methacrylate/chemical synthesis/*chemistry ; Pseudomonas aeruginosa/drug effects/physiology ; Quercetin/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/physiology ; Surface Properties ; }, abstract = {Pathogenic biofilms formed on the surfaces of implantable medical devices and materials pose an urgent global healthcare problem. Although conventional antibacterial surfaces based on bacteria-repelling or bacteria-killing strategies can delay biofilm formation to some extent, they usually fail in long-term applications, and it remains challenging to eradicate recalcitrant biofilms once they are established and mature. From the viewpoint of microbiology, a promising strategy may be to target the middle stage of biofilm formation including the main biological processes involved in biofilm development. In this work, a dual-functional antibiofilm surface is developed based on copolymer brushes of 2-hydroxyethyl methacrylate (HEMA) and 3-(acrylamido)phenylboronic acid (APBA), with quercetin (Qe, a natural antibiofilm molecule) incorporated via acid-responsive boronate ester bonds. Due to the antifouling properties of the hydrophilic poly(HEMA) component, the resulting surface is able to suppress bacterial adhesion and aggregation in the early stages of contact. A few bacteria are eventually able to break through the protection of the anti-adhesion layer leading to bacterial colonization. In response to the resulting decrease in the pH of the microenvironment, the surface could then release Qe to interfere with the microbiological processes related to biofilm formation. Compared to bactericidal and anti-adhesive surfaces, this dual-functional surface showed significantly improved antibiofilm performance to prevent biofilm formation involving both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus for up to 3 days. In addition, both the copolymer and Qe are negligibly cytotoxic, thereby avoiding possible harmful effects on adjacent normal cells and the risk of bacterial resistance. This dual-functional design approach addresses the different stages of biofilm formation, and (in accordance with the growth process of the biofilm) allows sequential activation of the functions without compromising the viability of adjacent normal cells. A simple and reliable solution may thus be provided to the problems associated with biofilms on surfaces in various biomedical applications.}, } @article {pmid34517785, year = {2021}, author = {Fu, R and Li, Z and Zhou, R and Li, C and Shao, S and Li, J}, title = {The mechanism of intestinal flora dysregulation mediated by intestinal bacterial biofilm to induce constipation.}, journal = {Bioengineered}, volume = {12}, number = {1}, pages = {6484-6498}, pmid = {34517785}, issn = {2165-5987}, mesh = {Animals ; Biofilms ; *Constipation/microbiology/physiopathology ; *Dysbiosis/microbiology/physiopathology ; Feces/microbiology ; Female ; Gastrointestinal Microbiome/*physiology ; Intestinal Mucosa/physiopathology ; Male ; Mice ; Serotonin Plasma Membrane Transport Proteins/metabolism ; }, abstract = {To explore mechanism of intestinal flora dysregulation promoting constipation, 60 specific pathogen-free (SPF) mice were used as research objects and were treated with constipation population fecal fluid gavage and distilled water gavage. Then, relationship between intestinal dysregulation and constipation in mice with biofilm-mediated intestinal flora was investigated in vitro. The results showed that recombinant serotonin transporter (SERT) messenger ribonucleic acid (mRNA) level of the constipation population fecal fluid gavage group and the relative expression level of SERT mRNA were 1.61 ± 0.08 and 1.49 ± 0.06, which were higher markedly than those of distilled water group (P < 0.05). The level of 5-hydroxytryptamine (5-HT) in colonic tissue of the constipation population fecal fluid gavage group was 145.36 ± 14.12 ng/mL, and the expression level of 5-HT on the surface of epithelial cells of biofilm-positive colonic tissue was 20.11 ± 2.03, which were significantly lower than those of the distilled water group, with statistical significance (P < 0.05). Besides, the microbial sequencing of fecal flora indicated that The Akk and bacteroidetes ofconstipation population fecal fluid gavage group were higher hugely than those of distilled water group (P < 0.05).In conclusion, after the occurrence of constipation, the diversity of intestinal microflora decreased, and the probiotics reduced. Iintestinal microflora dysregulation would lead to increase of SERT expression level in defecation function and intestinal motility in mice, and the decrease of 5-HT, thereby changing the intestinal movement resulting in mucosal protective barrier damage,thereby causing changes in intestinal movement and the destruction of the intestinal mucosal protective barrier, which eventually resulted in constipation. The occurrence of constipation could be improved by regulating balance of intestinal flora, increasing the diversity of flora, and reducing the genus of opportunistic pathogens.}, } @article {pmid34517574, year = {2021}, author = {T, AV and Paramanantham, P and Sb, SL and Sharan, A and Alsaedi, MH and Dawoud, TMS and Syed, A and Siddhardha, B}, title = {Corrigendum to "Antimicrobial photodynamic activity of rose bengal conjugated multi walled carbon nanotubes against planktonic cells and biofilm of Escherichia coli" [Photodiagn. Photodyn. Ther. 24 (2021) 300-310].}, journal = {Photodiagnosis and photodynamic therapy}, volume = {35}, number = {}, pages = {102363}, doi = {10.1016/j.pdpdt.2021.102363}, pmid = {34517574}, issn = {1873-1597}, } @article {pmid34517572, year = {2021}, author = {Gao, Y and Mai, B and Wang, A and Li, M and Wang, X and Zhang, K and Liu, Q and Wei, S and Wang, P}, title = {Corrigendum to "Antimicrobial properties of a new type of photosensitizer derived from phthalocyanine against planktonic and biofilm forms of Staphylococcus aureus" [Photodiagn. Photodyn. Ther. 21 (2018) 316-326].}, journal = {Photodiagnosis and photodynamic therapy}, volume = {35}, number = {}, pages = {102337}, doi = {10.1016/j.pdpdt.2021.102337}, pmid = {34517572}, issn = {1873-1597}, } @article {pmid34516283, year = {2021}, author = {Kasetty, S and Katharios-Lanwermeyer, S and O'Toole, GA and Nadell, CD}, title = {Differential Surface Competition and Biofilm Invasion Strategies of Pseudomonas aeruginosa PA14 and PAO1.}, journal = {Journal of bacteriology}, volume = {203}, number = {22}, pages = {e0026521}, pmid = {34516283}, issn = {1098-5530}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; P30-DK117469/NH/NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; R37-AI83256-06/NH/NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cell Death ; Lab-On-A-Chip Devices ; Pseudomonas aeruginosa/*classification/*physiology ; Surface Properties ; }, abstract = {Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best-characterized model organisms used to study the mechanisms of biofilm formation while also representing two distinct lineages of P. aeruginosa. Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, P. aeruginosa PA14 is better able to invade preformed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. IMPORTANCE Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naive surface, while PA14 is more effective in colonizing a preformed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.}, } @article {pmid34516241, year = {2021}, author = {Singulani, JL and Oliveira, LT and Ramos, MD and Fregonezi, NF and Gomes, PC and Galeane, MC and Palma, MS and Fusco Almeida, AM and Mendes Giannini, MJS}, title = {The Antimicrobial Peptide MK58911-NH2 Acts on Planktonic, Biofilm, and Intramacrophage Cells of Cryptococcus neoformans.}, journal = {Antimicrobial agents and chemotherapy}, volume = {65}, number = {12}, pages = {e0090421}, pmid = {34516241}, issn = {1098-6596}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)/ ; 2017/06658-9//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; //MCTI | Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)/ ; }, mesh = {Animals ; Antifungal Agents/*pharmacology ; Antimicrobial Peptides/*pharmacology ; Biofilms ; Cryptococcosis/drug therapy ; *Cryptococcus neoformans/drug effects ; Humans ; Macrophages/microbiology ; Microbial Sensitivity Tests ; Zebrafish ; }, abstract = {Cryptococcosis is associated with high rates of morbidity and mortality, especially in AIDS patients. Its treatment is carried out by combining amphotericin B and azoles or flucytosine, which causes unavoidable toxicity issues in the host. Thus, the urgency in obtaining new antifungals drives the search for antimicrobial peptides (AMPs). This study aimed to extend the understanding of the mechanism of action of an AMP analog from wasp peptide toxins, MK58911-NH2, on Cryptococcus neoformans. We also evaluated if MK58911-NH2 can act on cryptococcal cells in macrophages, biofilms, and an immersion zebrafish model of infection. Finally, we investigated the structure-antifungal action and the toxicity relationship of MK58911-NH2 fragments and a derivative of this peptide (MH58911-NH2). The results demonstrated that MK58911-NH2 did not alter the fluorescence intensity of the cell wall-binding dye calcofluor white or the capsule-binding dye 18b7 antibody-fluorescein isothiocyanate (FITC) in C. neoformans but rather reduced the number and size of fungal cells. This activity reduced the fungal burden of C. neoformans in both macrophages and zebrafish embryos as well as within biofilms. Three fragments of the MK58911-NH2 peptide showed no activity against Cryptococcus and not toxicity in lung cells. The derivative peptide MH58911-NH2, in which the lysine residues of MK58911-NH2 were replaced by histidines, reduced the activity against extracellular and intracellular C. neoformans. On the other hand, it was active against biofilms and showed reduced toxicity. In summary, these results showed that peptide MK58911-NH2 could be a promising agent against cryptococcosis. This work also opens a perspective for the verification of the antifungal activity of other derivatives.}, } @article {pmid34512560, year = {2021}, author = {Thieme, L and Hartung, A and Tramm, K and Graf, J and Spott, R and Makarewicz, O and Pletz, MW}, title = {Adaptation of the Start-Growth-Time Method for High-Throughput Biofilm Quantification.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {631248}, pmid = {34512560}, issn = {1664-302X}, abstract = {Colony forming unit (CFU) determination by agar plating is still regarded as the gold standard for biofilm quantification despite being time- and resource-consuming. Here, we propose an adaption of the high-throughput Start-Growth-Time (SGT) method from planktonic to biofilm analysis, which indirectly quantifies CFU/mL numbers by evaluating regrowth curves of detached biofilms. For validation, the effect of dalbavancin, rifampicin and gentamicin against mature biofilms of Staphylococcus aureus and Enterococcus faecium was measured by accessing different features of the viability status of the cell, i.e., the cultivability (conventional agar plating), growth behavior (SGT) and metabolic activity (resazurin assay). SGT correlated well with the resazurin assay for all tested antibiotics, but only for gentamicin and rifampicin with conventional agar plating. Dalbavancin treatment-derived growth curves showed a compared to untreated controls significantly slower increase with reduced cell doubling times and reduced metabolic rate, but no change in CFU numbers was observed by conventional agar plating. Here, unspecific binding of dalbavancin to the biofilm interfered with the SGT methodology since the renewed release of dalbavancin during detachment of the biofilms led to an unintended antimicrobial effect. The application of the SGT method for anti-biofilm testing is therefore not suited for antibiotics which stick to the biofilm and/or to the bacterial cell wall. Importantly, the same applies for the well-established resazurin method for anti-biofilm testing. However, for antibiotics which do not bind to the biofilm as seen for gentamicin and rifampicin, the SGT method presents a much less labor-intensive method suited for high-throughput screening of anti-biofilm compounds.}, } @article {pmid34511397, year = {2021}, author = {Segundo Zaragoza, C and López Ortiz, I and Contreras Caro Del Castillo, DA and Domínguez Hernández, YM and Rodríguez García, JA}, title = {Characterization, enzymatic activity and biofilm formation of Candida species isolated from goat milk.}, journal = {Revista iberoamericana de micologia}, volume = {38}, number = {4}, pages = {175-179}, doi = {10.1016/j.riam.2021.06.001}, pmid = {34511397}, issn = {2173-9188}, mesh = {Animals ; Biofilms ; *Candida ; Candida albicans ; Female ; Goats ; *Milk ; }, abstract = {BACKGROUND: Data regarding yeast microbiota in goat milk is scarce.

AIMS: To isolate and identify species of the genus Candida in milk samples from clinically healthy goats, and evaluate their enzymatic activity and biofilm formation.

METHODS: 1092 milk samples from clinically healthy goats were collected and processed. The yeast isolates were identified by phenotypic, methods and their enzymatic activity (phospholipase, hemolysin and protease) and biofilm formation evaluated.

RESULTS: We obtained 221 Candida isolates belonging to six species: Candida kefyr (35.7%), Candida guilliermondii (33%), Candida famata (23.5%), Candida glabrata (5.9%), Candida albicans (1.35%) and Candida parapsilosissensu lato (0.45%). Protease activity was detected in all Candida species while hemolysin activity was only present in C. kefyr, C. guilliermondii, C. famata and C. albicans. Only C. albicans showed phospholipase activity. With the exception of C. parapsilosis sensu lato, all Candida species formed biofilm, with 60.19% of the isolates being poor producers, 9.93% moderate producers, and 1.35% strong producers.

CONCLUSIONS: The milk of clinically healthy goats contains several species of the genus Candida that could play a role as opportunistic pathogens in mastitis.}, } @article {pmid34511035, year = {2021}, author = {Zhang, W and Li, H and Zhao, N and Luo, X and Liu, S and Bao, A and Chen, Y and Wang, H and Wang, J and Wang, J}, title = {Lactobacillus johnsonii BS15 combined with abdominal massage on intestinal permeability in rats with nonalcoholic fatty liver and cell biofilm repair.}, journal = {Bioengineered}, volume = {12}, number = {1}, pages = {6354-6363}, pmid = {34511035}, issn = {2165-5987}, mesh = {Animals ; Biofilms ; Diet, High-Fat ; Gastrointestinal Absorption/*physiology ; Intestinal Mucosa/metabolism ; *Lactobacillus johnsonii ; Liver/metabolism/pathology ; Male ; *Massage ; *Non-alcoholic Fatty Liver Disease/metabolism/pathology ; Rats ; Rats, Sprague-Dawley ; }, abstract = {This study aimed to analyze the effect of lactobacillus johnsonii BS15 (isolation of homemade yogurt from Ahu Hongyuan Grassland) combined with abdominal massage on intestinal permeability in rats with nonalcoholic fatty liver disease (NAFLD) and cell biofilm repair. Forty-five rats were divided randomly into five groups, four of which were fed with high-fat diet to establish NAFLD models. According to the treatment methods, they were grouped into group A (lactic acid bacteria feeding), group B (abdominal massage), group A + B (a combination of the two methods), model group (distilled water feeding), and normal group (distilled water feeding). Then, the pathological indexes of liver and intestinal permeability were observed. FITC-Dextran content of the model group elevated markedly compared with normal group (P < 0.01), indicating that the intestinal permeability of NAFLD rats fed with high-fat diet increased. The intestinal permeability of groups A, B, and A + B was lower sharply than that of model group (P < 0.01), and the effect of group A + B was the most obvious. HE staining of liver tissues showed that combined treatment could improve structural changes in liver cells caused by modeling and restore the normal structure of intestinal cells. Lactobacillus combined with abdominal massage was better than two treatments alone, further promoting the permeability of intestinal mucosa in NAFLD rats and repair biofilm of hepatocytes. The results initially verified the intervention effect of abdominal massage on intestinal mucosal permeability, and further revealed the mechanism of abdominal massage in treatment of NAFLD by improving intestinal mucosal barrier permeability.}, } @article {pmid34510307, year = {2021}, author = {Gomaa, OM and Abd El Kareem, H and Selim, N}, title = {Nitrate modulation of Bacillus sp. biofilm components: a proposed model for sustainable bioremediation.}, journal = {Biotechnology letters}, volume = {43}, number = {11}, pages = {2185-2197}, pmid = {34510307}, issn = {1573-6776}, mesh = {Azo Compounds/isolation & purification/metabolism ; *Bacillus/chemistry/genetics/metabolism ; *Biodegradation, Environmental ; *Biofilms ; Models, Biological ; Nitrates/*metabolism ; Wastewater/chemistry ; Water Purification ; }, abstract = {The presence of different pollutants in wastewater hinder microbial growth, compromise enzymatic activity or compete for electrons required for bioremediation pathway. Therefore, there is a need to use a single microorganism that is capable of tolerating different toxic compounds and can perform simultaneous bioremediation. In the present study, nitrate reducing bacteria capable of decolorizing azo dye was identified as Bacillus subtillis sp. DN using protein profiling, morphological and biochemical tests X-ray diffraction pattern, Raman spectroscopy and cyclic voltammetry confirm that the bacterium under study possesses membrane-bound nitrate reductase and that is capable of direct electron transfer. The addition of nitrate concentrations (0-50 mM) resulted in increased biofilm formation with variable exopolysaccharides, protein, and eDNA. Fourier Transform Infrared spectrum revealed the presence of a biopolymer at high nitrate concentrations. Effective capacitance and conductivity of the cells grown in different nitrate concentrations suggest changes in the relative position of polar groups, their relative orientation and permeability of cell membrane as detected by dielectric spectroscopy. The increase in biofilm shifted the removal of the azo dye from biodegradation to bioadsorption. Our results indicate that nitrate modulates biofilm components. Bacillus sp. DN granular biofilm can be used for simultaneous nitrate and azo dye removal from wastewater.}, } @article {pmid34509685, year = {2021}, author = {Garcia, BA and Panariello, BHD and Freitas-Pontes, KM and Duarte, S}, title = {Candida biofilm matrix as a resistance mechanism against photodynamic therapy.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {36}, number = {}, pages = {102525}, doi = {10.1016/j.pdpdt.2021.102525}, pmid = {34509685}, issn = {1873-1597}, mesh = {Candida ; Candida albicans ; Extracellular Polymeric Substance Matrix ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (aPDT) efficiency on Candida albicans is recognized in free-floating cultures. Though, the lack of aPDT effectiveness against C. albicans organized in biofilms is still unclear. This study aimed to explore the role of the extracellular matrix (ECM) in the protection against aPDT in C. albicans biofilms.

METHODS: C. albicans SN 425 wild-type and two mutant strains CNJ 2302; Δ/Δefg1 and CJN 2330; Δ/Δtec1 (ECM deficient) were used. Biofilms were grown on 24-well plates and exposed twice-daily to aPDT with 44 μM toluidine blue-O (TBO) for 5 min followed by red light (635 nm) for 1 min (87.6 J/cm²) or 2 min (175.2 J/cm[2]). Application of just TBO, light, 0.12% chlorhexidine, and ultrapure water were used as controls. After 48 h, biofilms were assessed for dry-weight (DW), colony forming units (CFU), extracellular DNA (eDNA), soluble and insoluble protein (SP/IP), water-insoluble (alkali-soluble) polysaccharide (ASP), water-soluble polysaccharides (WSP), and confocal scanning laser microscopy.

RESULTS: The strains with ECM deficient were affected by aPDT. For the mutant strain Δ/Δefg1, aPDT significantly reduced CFU, ASP, DW, eDNA, WSP and IP when compared to NC (p<0.001) and for the Δ/Δtec1, aPDT significantly reduced CFU, eDNA, IP and SP. Whereas CFU, DW, ASP of the wild-type strain biofilms were not reduced (p>0.05).

CONCLUSIONS: C. albicans strains with reduced ECM compounds were more sensitive to aPDT suggesting that the ECM may have a significant protection role from aPDT in C. albicans biofilms.}, } @article {pmid34507762, year = {2021}, author = {Fernández-Gómez, P and Figueredo, A and López, M and González-Raurich, M and Prieto, M and Alvarez-Ordóñez, A}, title = {Heterogeneity in biofilm formation and identification of biomarkers of strong biofilm formation among field isolates of Pseudomonas spp.}, journal = {Food research international (Ottawa, Ont.)}, volume = {148}, number = {}, pages = {110618}, doi = {10.1016/j.foodres.2021.110618}, pmid = {34507762}, issn = {1873-7145}, mesh = {Biofilms ; Biomarkers ; Food Handling ; *Pseudomonas ; *Stainless Steel ; }, abstract = {The biofilm formation ability of a collection of thirty-three Pseudomonas spp. isolates from food processing facilities was investigated in order to find biomarkers of strong biofilm production, a characteristic that can determine persistence in food processing environments. The strains were classified according to the colony pigmentation on solid media as green, brown or not pigmented. The biofilm production on stainless steel and polystyrene was assessed by spectrometric determination of the fixed crystal violet, and the biofilm formed on glass, through confocal laser scanning microscopy. Besides, pyoverdine production, catalase activity, RpoS status and cellular hydrophobicity were also monitored. A significantly higher biofilm production level on stainless steel and polystyrene was observed for green-pigmented strains as compared to brown or not pigmented strains. The influence of iron availability on biofilm formation on stainless steel was studied through the addition of the iron scavenger 2,2-bipyridine resulting in a decrease of 40 % in biofilm formation for the not pigmented strains. For most of the potential biomarkers studied (i.e., pyoverdine production, catalase activity, cellular hydrophobicity), the phenotypic heterogeneity observed among strains was mainly dependent on the Pseudomonas species and no strong associations with the biofilm formation capacity were detected. However, the green colony pigmentation on solid media showed good potential as a biomarker of strong biofilm formation on stainless steel and polystyrene both in P. aeruginosa and Pseudomonas spp.}, } @article {pmid34507740, year = {2021}, author = {Hossain, MI and Mizan, MFR and Roy, PK and Nahar, S and Toushik, SH and Ashrafudoulla, M and Jahid, IK and Lee, J and Ha, SD}, title = {Listeria monocytogenes biofilm inhibition on food contact surfaces by application of postbiotics from Lactobacillus curvatus B.67 and Lactobacillus plantarum M.2.}, journal = {Food research international (Ottawa, Ont.)}, volume = {148}, number = {}, pages = {110595}, doi = {10.1016/j.foodres.2021.110595}, pmid = {34507740}, issn = {1873-7145}, mesh = {Biofilms ; Lactobacillus ; *Lactobacillus plantarum ; *Listeria monocytogenes ; }, abstract = {Owing to their preservative and antimicrobial effects, postbiotics (metabolic byproducts of probiotics) are promising natural components for the food industry. Therefore, the present study aimed to investigate the efficacy of postbiotics collected from isolated Lactobacillus curvatus B.67 and Lactobacillus plantarum M.2 against Listeria monocytogenes pathogens in planktonic cells, motility, and biofilm states. The analysis of the metabolite composition of the postbiotics revealed various organic acids, along with a few well-known bacteriocin-encoding genes with potential antimicrobial effects. Postbiotics maintained their residual antimicrobial activity over the pH range 1-6 but lost all activity at neutral pH (pH 7). Full antimicrobial activity (100%) was observed during heat treatment, even under the autoclaving condition.Minimum inhibitory concentration (MICs) of L. curvatus B.67 and L. plantarum M.2 against L. monocytogenes were 80 and 70 mg/mL, respectively. However, four sub-MICs of the postbiotics (1/2, 1/4, 1/8, and 1/16 MIC) were tested for inhibition efficacy against L. monocytogenes during different experiment in this study. Swimming motility, biofilm formation, and expression levels of target genes related to biofilm formation, virulence, and quorum-sensing were significantly inhibited with increasing postbiotics concentration. Postbiotics from L. plantarum M.2 exhibited a higher inhibitory effect than the postbiotics from L. curvatus B.67. Nonetheless, both these postbiotics from Lactobacillus spp. could be used as effective bio-interventions for controlling L. monocytogenes biofilm in the food industry.}, } @article {pmid34506798, year = {2022}, author = {Oh, JH and Park, J and Park, Y}, title = {Anti-biofilm and anti-inflammatory effects of Lycosin-II isolated from spiders against multi-drug resistant bacteria.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1864}, number = {1}, pages = {183769}, doi = {10.1016/j.bbamem.2021.183769}, pmid = {34506798}, issn = {1879-2642}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Anti-Inflammatory Agents/pharmacology ; Antimicrobial Peptides/*chemistry/pharmacology ; Biofilms/*drug effects ; Cytokines/antagonists & inhibitors/genetics ; Drug Resistance, Multiple, Bacterial/*drug effects ; Erythrocytes/drug effects ; Fibroblasts/drug effects ; Gram-Negative Bacteria/drug effects/pathogenicity ; Gram-Positive Bacteria/drug effects/pathogenicity ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/pathogenicity ; Phagocytosis/drug effects ; Pseudomonas aeruginosa/drug effects/pathogenicity ; Sheep ; Spider Venoms/*chemistry/pharmacology ; Spiders/chemistry ; }, abstract = {Currently, multidrug-resistant bacteria are rapidly increasing worldwide because of the misuse or overuse of antibiotics. In particular, few options exist for treating infections caused by long-persisting oxacillin-resistant strains and recently proliferating carbapenem-resistant strains. Therefore, alternative treatments are urgently needed. The antimicrobial peptide (AMP) Lycosin-II is a peptide consisting of 21 amino acids isolated from the venom of the spider Lycosa singoriensis. Lycosin-II showed strong antibacterial activity and biofilm inhibition effects against gram-positive and gram-negative bacteria including oxacillin-resistant Staphylococcus aureus (S. aureus) and meropenem-resistant Pseudomonas aeruginosa (P. aeruginosa) isolated from patients. In addition, Lycosin-II was not cytotoxic against human foreskin fibroblast Hs27 or hemolytic against sheep red blood cells at the concentration of which exerted antibacterial activity. The mechanism of action of Lycosin-II involves binding to lipoteichoic acid and lipopolysaccharide of gram-positive and gram-negative bacterial membranes, respectively, to destroy the bacterial membrane. Moreover, Lycosin-II showed anti-inflammatory effects by inhibiting the expression of pro-inflammatory cytokines that are increased during bacterial infection in Hs27 cells. These results suggest that Lycosin-II can serve as a therapeutic agent against infections with multidrug-resistant strains.}, } @article {pmid34505216, year = {2022}, author = {Gross, M and Ashqar, F and Sionov, RV and Friedman, M and Eliashar, R and Zaks, B and Gati, I and Duanis-Assaf, D and Feldman, M and Steinberg, D}, title = {Sustained release varnish containing chlorhexidine for prevention of Streptococcus mutans biofilm formation on voice prosthesis surface: an in vitro study.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {25}, number = {1}, pages = {177-187}, pmid = {34505216}, issn = {1618-1905}, support = {20180025//The Israeli Cancer Association/ ; }, mesh = {Biofilms ; Chlorhexidine/pharmacology ; Delayed-Action Preparations ; *Larynx, Artificial ; *Streptococcus mutans ; }, abstract = {OBJECTIVES: In this study, we aimed to develop a novel, sustained release varnish (SRV) for voice prostheses (VP) releasing chlorhexidine (CHX), for the prevention of biofilm formation caused by the common oral bacteria Streptococcus mutans on VP surfaces.

METHODS: This study was performed in an in vitro model as a step towards future in vivo trials. VPs were coated with a SRV containing CHX (SRV-CHX) or SRV alone (placebo-SRV) that were daily exposed to S. mutans. The polymeric materials of SRV were composed of ethylcellulose and PEG-400. Biofilm formation was assessed by DNA quantification (qPCR), crystal violet staining, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and kinetics experiments.

RESULTS: The amount of DNA in the biofilms formed by S. mutans on VP surfaces coated once with SRV-CHX (1.024 ± 0.218 ng DNA/piece) was 58.5 ± 8.8% lower than that of placebo-SRV-coated VPs (2.465 ± 0.198 ng DNA/piece) after a 48-h exposure to S. mutans (p = 0.038). Reduced biofilm mass on SRV-CHX-coated VPs was visually confirmed by CLSM and SEM. CV staining of SRV-CHX single-coated VPs that have been exposed to S. mutans nine times showed a 98.1 ± 0.2% reduction in biofilm mass compared to placebo-SRV-coated VPs (p = 0.003). Kinetic experiments revealed that SRV-CHX triple-coated VPs could delay bacterial growth for 23 days.

CONCLUSIONS: Coating VPs with SRV-CHX has an inhibitory effect on biofilm formation and prevents bacterial growth in their vicinities. This study is a proof-of-principle that paves the way for developing new clinical means for reducing both VPs' bacterial biofilm formation and device failure.}, } @article {pmid34504987, year = {2021}, author = {Arias, SL and Brito, IL}, title = {Biophysical determinants of biofilm formation in the gut.}, journal = {Current opinion in biomedical engineering}, volume = {18}, number = {}, pages = {}, pmid = {34504987}, issn = {2468-4511}, support = {R33 CA235302/CA/NCI NIH HHS/United States ; }, abstract = {The gastrointestinal (GI) tract harbors the most complex microbial ecosystem in the human body. The mucosal layer that covers the GI tract serves as a polymer-based defensive barrier that prevents the microbiome from reaching the epithelium and disseminating inside the body. Colonization of the mucus may result in the formation of structured polymicrobial communities or biofilms, a hallmark in pathologies such as colorectal cancer, inflammatory bowel disease, and chronic gut wounds. However, the mechanisms by which multispecies biofilms establish on the gut mucosa is unknown. Whether mucus-associated biofilms exist as part of a healthy mucosal barrier is still debated. Here, we discuss the impact that diet and microbial-derived polymers has on mucus structure and microcolony formation and highlight relevant biophysical forces that further shape nascent biofilms.}, } @article {pmid34504737, year = {2021}, author = {Janssen, K and Low, SL and Wang, Y and Mu, QY and Bierbaum, G and Gee, CT}, title = {Elucidating biofilm diversity on water lily leaves through 16S rRNA amplicon analysis: Comparison of four DNA extraction kits.}, journal = {Applications in plant sciences}, volume = {9}, number = {8}, pages = {e11444}, pmid = {34504737}, issn = {2168-0450}, abstract = {PREMISE: Within a broader study on leaf fossilization in freshwater environments, a long-term study on the development and microbiome composition of biofilms on the foliage of aquatic plants has been initiated to understand how microbes and biofilms contribute to leaf decay and preservation. Here, water lily leaves are employed as a study model to investigate the relationship between bacterial microbiomes, biodegradation, and fossilization. We compare four DNA extraction kits to reduce biases in interpretation and to identify the most suitable kit for the extraction of DNA from bacteria associated with biofilms on decaying water lily leaves for 16S rRNA amplicon analysis.

METHODS: We extracted surface-associated DNA from Nymphaea leaves in early stages of decay at two water depth levels using four commercially available kits to identify the most suitable protocol for bacterial extraction, applying a mock microbial community standard to enable a reliable comparison of the kits.

RESULTS: Kit 4, the FastDNA Spin Kit for Soil, resulted in high DNA concentrations with better quality and yielded the most accurate depiction of the mock community. Comparison of the leaves at two water depths showed no significant differences in community composition.

DISCUSSION: The success of Kit 4 may be attributed to its use of bead beating with a homogenizer, which was more efficient in the lysis of Gram-positive bacteria than the manual vortexing protocols used by the other kits. Our results show that microbial composition on leaves during early decay remains comparable and may change only in later stages of decomposition.}, } @article {pmid34503352, year = {2021}, author = {Sharma, A and Vashistt, J and Shrivastava, R}, title = {Response surface modeling integrated microtiter plate assay for Mycobacterium fortuitum biofilm quantification.}, journal = {Biofouling}, volume = {37}, number = {8}, pages = {830-843}, doi = {10.1080/08927014.2021.1974846}, pmid = {34503352}, issn = {1029-2454}, mesh = {Biofilms ; *Mycobacterium fortuitum ; }, abstract = {In this study, the effects of agitation, temperature, and pH on biofilm formation by Mycobacterium fortuitum were studied and quantified through response surface modeling. The microtiter plate assay was optimized to achieve conditions favoring maximum mycobacterial biofilm quantification. Optical density (OD) measurement using a crystal violet assay was performed to estimate the amount of biofilm formed. Response surface methodology (RSM) results revealed an R[2] value of 96.18%, exhibiting a maximum OD of 2.119 (λ570 nm) at a temperature of 37 °C and pH 7.0, under a static environment. The conditions were experimentally validated. Statistically significant results showed that the maximum biofilm was produced 96 h after mycobacterial inoculation. Thus, the results provide a basis for using RSM as an efficient optimization method for M. fortuitum biofilm assays. This approach can also be incorporated into strategies for screening anti-biofilm compounds, synthetic chemicals, drugs, or inhibitors against pathogenic mycobacteria.}, } @article {pmid34502269, year = {2021}, author = {Pusparajah, P and Letchumanan, V and Law, JW and Ab Mutalib, NS and Ong, YS and Goh, BH and Tan, LT and Lee, LH}, title = {Streptomyces sp.-A Treasure Trove of Weapons to Combat Methicillin-Resistant Staphylococcus aureus Biofilm Associated with Biomedical Devices.}, journal = {International journal of molecular sciences}, volume = {22}, number = {17}, pages = {}, pmid = {34502269}, issn = {1422-0067}, support = {FRGS/1/2019/SKK08/MUSM/02/7//Ministry of Education - Fundamental Research Grant Scheme/ ; ECR-000014//JCSMHS Early Career Researcher Grant 2021/ ; }, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/therapeutic use ; Biofilms/*drug effects/growth & development ; Equipment and Supplies/*adverse effects/microbiology ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Prosthesis-Related Infections/*drug therapy ; Staphylococcal Infections/*drug therapy ; Streptomyces/*chemistry/isolation & purification/*metabolism ; }, abstract = {Biofilms formed by methicillin-resistant S. aureus (MRSA) are among the most frequent causes of biomedical device-related infection, which are difficult to treat and are often persistent and recurrent. Thus, new and effective antibiofilm agents are urgently needed. In this article, we review the most relevant literature of the recent years reporting on promising anti-MRSA biofilm agents derived from the genus Streptomyces bacteria, and discuss the potential contribution of these newly reported antibiofilm compounds to the current strategies in preventing biofilm formation and eradicating pre-existing biofilms of the clinically important pathogen MRSA. Many efforts are evidenced to address biofilm-related infections, and some novel strategies have been developed and demonstrated encouraging results in preclinical studies. Nevertheless, more in vivo studies with appropriate biofilm models and well-designed multicenter clinical trials are needed to assess the prospects of these strategies.}, } @article {pmid34499698, year = {2021}, author = {Taggart, MG and Snelling, WJ and Naughton, PJ and La Ragione, RM and Dooley, JSG and Ternan, NG}, title = {Biofilm regulation in Clostridioides difficile: Novel systems linked to hypervirulence.}, journal = {PLoS pathogens}, volume = {17}, number = {9}, pages = {e1009817}, pmid = {34499698}, issn = {1553-7374}, mesh = {Biofilms/*growth & development ; Clostridioides difficile/*growth & development/*pathogenicity ; Clostridium Infections/*pathology ; Humans ; Virulence ; }, abstract = {Clostridiodes difficile (C. difficile) was ranked an "urgent threat" by the Centers for Disease Control and Prevention (CDC) in 2019. C. difficile infection (CDI) is the most common healthcare-associated infection (HAI) in the United States of America as well as the leading cause of antibiotic-associated gastrointestinal disease. C. difficile is a gram-positive, rod-shaped, spore-forming, anaerobic bacterium that causes infection of the epithelial lining of the gut. CDI occurs most commonly after disruption of the human gut microflora following the prolonged use of broad-spectrum antibiotics. However, the recurrent nature of this disease has led to the hypothesis that biofilm formation may play a role in its pathogenesis. Biofilms are sessile communities of bacteria protected from extracellular stresses by a matrix of self-produced proteins, polysaccharides, and extracellular DNA. Biofilm regulation in C. difficile is still incompletely understood, and its role in disease recurrence has yet to be fully elucidated. However, many factors have been found to influence biofilm formation in C. difficile, including motility, adhesion, and hydrophobicity of the bacterial cells. Small changes in one of these systems can greatly influence biofilm formation. Therefore, the biofilm regulatory system would need to coordinate all these systems to create optimal biofilm-forming physiology under appropriate environmental conditions. The coordination of these systems is complex and multifactorial, and any analysis must take into consideration the influences of the stress response, quorum sensing (QS), and gene regulation by second messenger molecule cyclic diguanosine monophosphate (c-di-GMP). However, the differences in biofilm-forming ability between C. difficile strains such as 630 and the "hypervirulent" strain, R20291, make it difficult to assign a "one size fits all" mechanism to biofilm regulation in C. difficile. This review seeks to consolidate published data regarding the regulation of C. difficile biofilms in order to identify gaps in knowledge and propose directions for future study.}, } @article {pmid34497894, year = {2021}, author = {Fasiku, VO and Omolo, CA and Devnarain, N and Ibrahim, UH and Rambharose, S and Faya, M and Mocktar, C and Singh, SD and Govender, T}, title = {Chitosan-Based Hydrogel for the Dual Delivery of Antimicrobial Agents Against Bacterial Methicillin-Resistant Staphylococcus aureus Biofilm-Infected Wounds.}, journal = {ACS omega}, volume = {6}, number = {34}, pages = {21994-22010}, pmid = {34497894}, issn = {2470-1343}, abstract = {Chronic wound infections caused by antibiotic-resistant bacteria have become a global health concern. This is attributed to the biofilm-forming ability of bacteria on wound surfaces, thus enabling their persistent growth. In most cases, it leads to morbidity and in severe cases mortality. Current conventional approaches used in the treatment of biofilm wounds are proving to be ineffective due to limitations such as the inability to penetrate the biofilm matrix; hence, biofilm-related wounds remain a challenge. Therefore, there is a need for more efficient alternate therapeutic interventions. Hydrogen peroxide (HP) is a known antibacterial/antibiofilm agent; however, prolonged delivery has been challenging due to its short half-life. In this study, we developed a hydrogel for the codelivery of HP and antimicrobial peptides (Ps) against bacteria, biofilms, and wound infection associated with biofilms. The hydrogel was prepared via the Michael addition technique, and the physiochemical properties were characterized. The safety, in vitro, and in vivo antibacterial/antibiofilm activity of the hydrogel was also investigated. Results showed that the hydrogel is biosafe. A greater antibacterial effect was observed with HP-loaded hydrogels (CS-HP; hydrogel loaded with HP and CS-HP-P; hydrogel loaded with HP and peptide) when compared to HP as seen in an approximately twofold and threefold decrease in minimum inhibitory concentration values against methicillin-resistant Staphylococcus aureus (MRSA) bacteria, respectively. Similarly, both the HP-releasing hydrogels showed enhanced antibiofilm activity in the in vivo study in mice models as seen in greater wound closure and enhanced wound healing in histomorphological analysis. Interestingly, the results revealed a synergistic antibacterial/antibiofilm effect between HP and P in both in vitro and in vivo studies. The successfully prepared HP-releasing hydrogels showed the potential to combat bacterial biofilm-related infections and enhance wound healing in mice models. These results suggest that the HP-releasing hydrogels may be a superior platform for eliminating bacterial biofilms without using antibiotics in the treatment of chronic MRSA wound infections, thus improving the quality of human health.}, } @article {pmid34496717, year = {2021}, author = {Martins Antunes de Melo, WC and Celiešiūtė-Germanienė, R and Šimonis, P and Stirkė, A}, title = {Antimicrobial photodynamic therapy (aPDT) for biofilm treatments. Possible synergy between aPDT and pulsed electric fields.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {2247-2272}, pmid = {34496717}, issn = {2150-5608}, mesh = {*Anti-Infective Agents/pharmacology ; *Biofilms ; Electricity ; Extracellular Polymeric Substance Matrix ; Humans ; Oxygen ; *Photochemotherapy ; *Photosensitizing Agents/pharmacology ; Reactive Oxygen Species ; }, abstract = {Currently, microbial biofilms have been the cause of a wide variety of infections in the human body, reaching 80% of all bacterial and fungal infections. The biofilms present specific properties that increase the resistance to antimicrobial treatments. Thus, the development of new approaches is urgent, and antimicrobial photodynamic therapy (aPDT) has been shown as a promising candidate. aPDT involves a synergic association of a photosensitizer (PS), molecular oxygen and visible light, producing highly reactive oxygen species (ROS) that cause the oxidation of several cellular components. This therapy attacks many components of the biofilm, including proteins, lipids, and nucleic acids present within the biofilm matrix; causing inhibition even in the cells that are inside the extracellular polymeric substance (EPS). Recent advances in designing new PSs to increase the production of ROS and the combination of aPDT with other therapies, especially pulsed electric fields (PEF), have contributed to enhanced biofilm inhibition. The PEF has proven to have antimicrobial effect once it is known that extensive chemical reactions occur when electric fields are applied. This type of treatment kills microorganisms not only due to membrane rupture but also due to the formation of reactive compounds including free oxygen, hydrogen, hydroxyl and hydroperoxyl radicals. So, this review aims to show the progress of aPDT and PEF against the biofilms, suggesting that the association of both methods can potentiate their effects and overcome biofilm infections.}, } @article {pmid34495971, year = {2021}, author = {Santos, AAN and Ribeiro, PDS and da França, GV and Souza, FN and Ramos, EAG and Figueira, CP and Reis, MG and Costa, F and Ristow, P}, title = {Leptospira interrogans biofilm formation in Rattus norvegicus (Norway rats) natural reservoirs.}, journal = {PLoS neglected tropical diseases}, volume = {15}, number = {9}, pages = {e0009736}, pmid = {34495971}, issn = {1935-2735}, support = {/WT_/Wellcome Trust/United Kingdom ; R01 AI052473/AI/NIAID NIH HHS/United States ; R01 TW009504/TW/FIC NIH HHS/United States ; R25 TW009338/TW/FIC NIH HHS/United States ; 102330/Z/13/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Animals ; *Biofilms ; Disease Reservoirs/*microbiology ; Kidney/microbiology ; Leptospira interrogans/genetics/*physiology ; Leptospirosis/microbiology/*veterinary ; Male ; Rats ; Rodent Diseases/*microbiology ; }, abstract = {Rattus norvegicus (Norway rat) is the main reservoir host of pathogenic Leptospira, the causative agent of leptospirosis, in urban environments. Pathogenic Leptospira forms biofilms in the environment, possibly contributing for bacterial survival and maintenance. Nonetheless, biofilms have not yet been studied in natural animal reservoirs presenting leptospiral renal carriage. Here, we described biofilm formation by pathogenic Leptospira inside the renal tubules of R. norvegicus naturally infected and captured in an urban slum endemic for leptospirosis. From the 65 rats carrying Leptospira in their kidneys, 24 (37%) presented biofilms inside the renal tubules. The intensity of leptospiral colonization in the renal tubules (OR: 1.00; 95% CI 1.05-1.1) and the type of occlusion pattern of the colonized renal tubules (OR: 3.46; 95% CI 1.20-9.98) were independently associated with the presence of Leptospira biofilm. Our data showed that Leptospira interrogans produce biofilms during renal chronic colonization in rat reservoirs, suggesting a possible role for leptospiral biofilms in the pathogenesis of leptospirosis and bacterial carriage in host reservoirs.}, } @article {pmid34495103, year = {2021}, author = {Viana, CS and Maske, TT and Signori, C and VAN DE Sande, FH and Oliveira, EF and Cenci, MS}, title = {Influence of caries activity and number of saliva donors: mineral and microbiological responses in a microcosm biofilm model.}, journal = {Journal of applied oral science : revista FOB}, volume = {29}, number = {}, pages = {e20200778}, pmid = {34495103}, issn = {1678-7765}, mesh = {Biofilms ; *Dental Caries ; Dental Caries Susceptibility ; Humans ; Minerals ; *Saliva ; Streptococcus mutans ; }, abstract = {OBJECTIVE: this study evaluated the mineral and microbiological response of biofilms originating from different types of saliva inoculum with distinct levels of caries activity.

METHODOLOGY: the biofilms grown over enamel specimens originated from saliva collected from a single donor or five donors with two distinct levels of caries activity (caries-active and caries-free) or from pooling saliva from ten donors (five caries-active and five caries-free). The percentage surface hardness change (%SHC) and microbiological counts served as outcome variables.

RESULTS: the caries activity of donors did not affect the %SHC values. Inoculum from five donors compared to a single donor showed higher %SHC values (p=0.019). Higher lactobacilli counts were observed when saliva from caries-active donors was used as the inoculum (p=0.017). Pooled saliva from both caries activity levels showed higher mutans streptococci counts (p<0.017).

CONCLUSION: Overall, pooled saliva increased the mineral response of the derived biofilms, but all the inoculum conditions formed cariogenic biofilms and caries lesions independently of caries activity.}, } @article {pmid34494311, year = {2021}, author = {Togo, Y}, title = {Editorial Comment to Intraluminal diamond-like carbon coating with anti-adhesion and anti-biofilm effects for uropathogens: A novel technology applicable to urinary catheters.}, journal = {International journal of urology : official journal of the Japanese Urological Association}, volume = {28}, number = {12}, pages = {1289}, doi = {10.1111/iju.14691}, pmid = {34494311}, issn = {1442-2042}, mesh = {Biofilms ; *Carbon ; Escherichia coli ; Humans ; Technology ; *Urinary Catheters/adverse effects ; }, } @article {pmid34494127, year = {2022}, author = {Liu, Y and Luan, J}, title = {Letter to the Editor: Proper Skin Management in Breast Augmentation with a Periareolar Incision Prevents Implant Contamination and Biofilm-Related Capsular Contracture.}, journal = {Aesthetic plastic surgery}, volume = {46}, number = {Suppl 1}, pages = {9-10}, pmid = {34494127}, issn = {1432-5241}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; *Contracture/surgery ; Humans ; Implant Capsular Contracture/prevention & control/surgery ; *Mammaplasty ; }, } @article {pmid34492866, year = {2021}, author = {Zhou, B and Hou, P and Xiao, Y and Song, P and Xie, E and Li, Y}, title = {Visualizing, quantifying, and controlling local hydrodynamic effects on biofilm accumulation in complex flow paths.}, journal = {Journal of hazardous materials}, volume = {416}, number = {}, pages = {125937}, doi = {10.1016/j.jhazmat.2021.125937}, pmid = {34492866}, issn = {1873-3336}, mesh = {Biofilms ; Computer Simulation ; *Hydrodynamics ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Complex flow paths (CFPs) are commonly applied in precision equipment to accurately supply controllable fluids with designed structures. However, the presence of biofilms in CFPs causes quite a few unwanted issues, such as bio-erosion, clogging, or even health risks. To date, visualizing and quantifying the interaction between biofilm distribution and local hydrodynamics remains difficult, and the mechanism during the process is unclear. In this paper, the remodeling simulation method (3D industrial computed tomography scanning-inverse modeling-numerical simulation) and 16S rRNA high-throughput sequencing were integrated. The results indicated that local hydrodynamic characteristics significantly affected biofilm thicknesses on CFP surfaces (relative differences of 41.3-71.2%), which inversely influenced the local turbulence intensity. The average biofilm thicknesses exhibited a significant quadratic correlation with the near-wall hydraulic shear forces (r > 0.72, p < 0.05), and the biofilm reached a maximum thickness at 0.36-0.45 Pa. On the other hand, the near-wall hydraulic shear forces not only affected microbial community characteristics of biofilms, but they also influenced the number of microorganisms involved, which determined the biofilm accumulation thereafter. The PHYLUM Firmicutes and Proteobacteria were the dominant bacteria during the process. The results obtained in this paper could provide practical conceptions for the targeted control of biofilms and put forward more efficient controlling methods in commonly applied CFP systems.}, } @article {pmid34492791, year = {2021}, author = {Yang, T and Jiang, L and Cheng, L and Zheng, X and Bi, X and Wang, X and Zhou, X}, title = {Characteristics of size-segregated aerosols emitted from an aerobic moving bed biofilm reactor at a full-scale wastewater treatment plant.}, journal = {Journal of hazardous materials}, volume = {416}, number = {}, pages = {125833}, doi = {10.1016/j.jhazmat.2021.125833}, pmid = {34492791}, issn = {1873-3336}, mesh = {Aerosols/analysis ; *Biofilms ; Bioreactors ; Particulate Matter ; *Water Purification ; }, abstract = {Aerosol emissions from wastewater treatment plants (WWTPs) have been associated with health reverberation but studies about characteristics of size-segregated aerosol particulate matter (PM) are scarce. In this study, the measurement of particulate number size distribution in the range of < 10 µm, and the collection of PM10-2.5, PM2.5-1.0 and PM1.0, were conducted from an aerobic moving bed biofilm reactor (MBBR) at a full-scale WWTP. MBBR aerosols showed a unimodal number size distribution, with the majority of particles (>94%) in the ultrafine size range (<100 nm). For toxic metal(loid)s or potential pathogens, significant differences were found within MBBR aerosols (PM10-2.5, PM2.5-1.0, and PM1.0), and also between MBBR aerosols and wastewater. Both wastewater and ambient air had important source contributions for MBBR aerosols. The compositions of toxic metal(loid)s in PM1.0, and the populations of potential bacterial or fungal pathogens in PM10-2.5 and PM2.5-1.0, were dominated by that from wastewater. Compared to PM10-2.5 and PM2.5-1.0, PM1.0 had the highest aerosolization potential for the toxic metal(loid)s of As, Cd, Co, Cr, Li, Mn, Ni, U, and Zn, and the genera of Acinetobacter, Pseudomonas and Fusarium. Due to the size-segregated specialty, targeted measures should be employed to reduce the health risks. CAPSULE: The compositions of toxic metal(loid)s in PM1.0, and the populations of potential pathogens in PM10-2.5 and PM2.5-1.0, were dominated by that from wastewater.}, } @article {pmid34489569, year = {2021}, author = {Deng, X and Zhang, C and Chen, J and Shi, Y and Ma, X and Wang, Y and Wang, Z and Yu, Z and Zheng, J and Chen, Z}, title = {Antibacterial and anti-biofilm activities of histidine kinase YycG inhibitors against Streptococcus agalactiae.}, journal = {The Journal of antibiotics}, volume = {74}, number = {12}, pages = {874-883}, pmid = {34489569}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Daptomycin/pharmacology ; Histidine Kinase/*antagonists & inhibitors ; Inhibitory Concentration 50 ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Protein Kinase Inhibitors/chemistry/*pharmacology ; Streptococcus agalactiae/*drug effects/enzymology ; Thiazoles/chemistry/*pharmacology ; }, abstract = {This study aims to investigate the antibacterial and anti-biofilm activities of YycG inhibitors H2-60 and H2-81 against Streptococcus agalactiae. A total of 118 nonduplicate S. agalactiae clinical isolates were collected, and the minimal inhibitory concentrations (MICs) of H2-60 and H2-81 were determined. H2-60 and H2-81 inhibit biofilm formation of S. agalactiae were detected by crystal violet staining, and against established biofilms of S. agalactiae were observed by confocal laser scanning microscope. Inhibitory effect of H2-60 and H2-81 on the phosphorylation activity of the HisKA domain of YycG' protein was measured. The MIC50/MIC90 was 3.13/6.25 μM for H2-60 and 6.25/12.5 μM for H2-81 against S. agalactiae, respectively. S. agalactiae planktonic cells can be decreased by H2-60 or H2-81 for more than 3 × log10 CFU ml[-1] after 24 h treatment. Biofilm formation of 8 S. agalactiae strains (strong biofilm producers) was significantly reduced after treated with 1/4 × MIC of H2-60 or H2-81 for 24 h. H2-60 and H2-81 could reduce 45.79% and 29.56% of the adherent cells in the established biofilm of S. agalactiae after 72 h treatment, respectively. H2-60 combined with daptomycin reduced 83.63% of the adherent cells in the established biofilm of S. agalactiae, which was significantly better than that of H2-60 (45.79%) or daptomycin (55.07%) alone. The half maximal inhibitory concentrations (IC50) were 35.6 μM for H2-60 and 46.3 μM for H2-81 against the HisKA domain of YycG' protein. In conclusion, YycG inhibitors H2-60 and H2-81 exhibit excellent antibacterial and anti-biofilm activities against S. agalactiae.}, } @article {pmid34489479, year = {2021}, author = {Duraj-Thatte, AM and Praveschotinunt, P and Nash, TR and Ward, FR and Nguyen, PQ and Joshi, NS}, title = {Author Correction: Modulating bacterial and gut mucosal interactions with engineered biofilm matrix proteins.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {18033}, doi = {10.1038/s41598-021-96036-w}, pmid = {34489479}, issn = {2045-2322}, support = {R01 DK110770/DK/NIDDK NIH HHS/United States ; }, } @article {pmid34488149, year = {2021}, author = {Dong, X and Zhu, L and Jiang, P and Wang, X and Liu, K and Li, C and Li, D}, title = {Seasonal biofilm formation on floating microplastics in coastal waters of intensified marinculture area.}, journal = {Marine pollution bulletin}, volume = {171}, number = {}, pages = {112914}, doi = {10.1016/j.marpolbul.2021.112914}, pmid = {34488149}, issn = {1879-3363}, mesh = {Biofilms ; China ; Environmental Monitoring ; *Microplastics ; Plastics ; Seasons ; *Water Pollutants, Chemical/analysis ; }, abstract = {The environmental pollution caused by microplastics has received increasing attention recently. In this paper, we present the results of research into the bacterium attached to microplastics in four coastal mariculture zones in southeast China during winter and summer. Polyethene and polypropylene are the main microplastics in the surface water of mariculture area. The differences between the bacteria species composition found on the surface of microplastics in winter and summer were less than that found in the planktonic bacteria, indicating that biofilms protect the bacterium that live inside. Potentially pathogenic Vibrio and Pseudomonas spp. were more abundant in samples from ShanTou and QuanZhou during the summer. Bacteria related to the degradation of microplastics were found extensively on the surface of microplastics at all of the sampling sites. More attention should be paid to the risks resulting from the accumulation of harmful bacteria on microplastic surfaces during the summer.}, } @article {pmid34486975, year = {2021}, author = {Kalamara, M and Abbott, JC and MacPhee, CE and Stanley-Wall, NR}, title = {Biofilm hydrophobicity in environmental isolates of Bacillus subtilis.}, journal = {Microbiology (Reading, England)}, volume = {167}, number = {9}, pages = {}, doi = {10.1099/mic.0.001082}, pmid = {34486975}, issn = {1465-2080}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M010996/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Bacillus subtilis/genetics ; *Bacterial Proteins/genetics ; Biofilms ; Extracellular Matrix ; Hydrophobic and Hydrophilic Interactions ; }, abstract = {Biofilms are communities of bacteria that are attached to a surface and surrounded by an extracellular matrix. The extracellular matrix protects the community from stressors in the environment, making biofilms robust. The Gram-positive soil bacterium Bacillus subtilis, particularly the isolate NCIB 3610, is widely used as a model for studying biofilm formation. B. subtilis NCIB 3610 forms colony biofilms that are architecturally complex and highly hydrophobic. The hydrophobicity is linked, in part, to the localisation of the protein BslA at the surface of the biofilm, which provides the community with increased resistance to biocides. As most of our knowledge about B. subtilis biofilm formation comes from one isolate, it is unclear if biofilm hydrophobicity is a widely distributed feature of the species. To address this knowledge gap, we collated a library of B. subtilis soil isolates and acquired their whole genome sequences. We used our novel isolates to examine biofilm hydrophobicity and found that, although BslA is encoded and produced by all isolates in our collection, hydrophobicity is not a universal feature of B. subtilis colony biofilms. To test whether the matrix exopolymer poly γ-glutamic acid could be masking hydrophobicity in our hydrophilic isolates, we constructed deletion mutants and found, contrary to our hypothesis, that the presence of poly γ-glutamic acid was not the reason for the observed hydrophilicity. This study highlights the natural variation in the properties of biofilms formed by different isolates and the importance of using a more diverse range of isolates as representatives of a species.}, } @article {pmid34485498, year = {2021}, author = {Boswell, MT and Cockeran, R}, title = {Effect of antimicrobial peptides on planktonic growth, biofilm formation and biofilm-derived bacterial viability of Streptococcus pneumoniae.}, journal = {Southern African journal of infectious diseases}, volume = {36}, number = {1}, pages = {226}, pmid = {34485498}, issn = {2313-1810}, abstract = {Streptococcus pneumoniae is a leading cause of pneumonia mortality globally. Pneumococcal disease is often associated with prolonged colonisation of hosts and this process is facilitated by biofilm formation that is largely resistant to conventional antibiotics. We investigated the effects of antimicrobial peptides (AMPs) lysozyme, lactoferrin, LL37 and a combination of all three on planktonic growth, biofilm formation and biofilm-derived bacterial viability by S. pneumoniae, serotype 23F. Planktonic growth and biofilm-derived bacterial viability were determined using standard colony-forming techniques, while biofilm formation was measured using a crystal violet based spectrophotometric method. Relative to controls, lysozyme significantly reduced biofilm formation (0.08 OD vs. 0.10 OD at 570 nm, p = 0.01), while LL37 and the AMP combination increased biofilm formation (0.14 OD vs. 0.10 OD at 570 nm, p = 0.01). The combination of AMPs significantly decreased planktonic growth (1.10 × 10[8] colony-forming units per millilitres [CFU/mL] vs. 2.13 × 10[8] CFU/mL, p = 0.02). Biofilm-derived bacterial viability was greatly reduced by exposure to a combination of AMPs (1.05 × 10[5] CFU/mL vs. 1.12 × 10[6] CFU/mL, p = 3.60 × 10[-8]). Streptococcus pneumoniae displays marked resistance to the individual AMPs. A combination of lysozyme, lactoferrin and LL37 effectively inhibited planktonic growth and biofilm-derived bacterial viability; however, persister cell growth was still evident after exposure.}, } @article {pmid34485167, year = {2021}, author = {Ramírez-Granillo, A and Bautista-Hernández, LA and Bautista-De Lucío, VM and Magaña-Guerrero, FS and Domínguez-López, A and Córdova-Alcántara, IM and Pérez, NO and Martínez-Rivera, MLA and Rodríguez-Tovar, AV}, title = {Microbial Warfare on Three Fronts: Mixed Biofilm of Aspergillus fumigatus and Staphylococcus aureus on Primary Cultures of Human Limbo-Corneal Fibroblasts.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {646054}, pmid = {34485167}, issn = {2235-2988}, mesh = {*Aspergillus fumigatus ; Biofilms ; Cornea ; Fibroblasts ; Humans ; *Staphylococcus aureus ; }, abstract = {BACKGROUND: Coinfections with fungi and bacteria in ocular pathologies are increasing at an alarming rate. Two of the main etiologic agents of infections on the corneal surface, such as Aspergillus fumigatus and Staphylococcus aureus, can form a biofilm. However, mixed fungal-bacterial biofilms are rarely reported in ocular infections. The implementation of cell cultures as a study model related to biofilm microbial keratitis will allow understanding the pathogenesis in the cornea. The cornea maintains a pathogen-free ocular surface in which human limbo-corneal fibroblast cells are part of its cell regeneration process. There are no reports of biofilm formation assays on limbo-corneal fibroblasts, as well as their behavior with a polymicrobial infection.

OBJECTIVE: To determine the capacity of biofilm formation during this fungal-bacterial interaction on primary limbo-corneal fibroblast monolayers.

RESULTS: The biofilm on the limbo-corneal fibroblast culture was analyzed by assessing biomass production and determining metabolic activity. Furthermore, the mixed biofilm effect on this cell culture was observed with several microscopy techniques. The single and mixed biofilm was higher on the limbo-corneal fibroblast monolayer than on abiotic surfaces. The A. fumigatus biofilm on the human limbo-corneal fibroblast culture showed a considerable decrease compared to the S. aureus biofilm on the limbo-corneal fibroblast monolayer. Moreover, the mixed biofilm had a lower density than that of the single biofilm. Antibiosis between A. fumigatus and S. aureus persisted during the challenge to limbo-corneal fibroblasts, but it seems that the fungus was more effectively inhibited.

CONCLUSION: This is the first report of mixed fungal-bacterial biofilm production and morphological characterization on the limbo-corneal fibroblast monolayer. Three antibiosis behaviors were observed between fungi, bacteria, and limbo-corneal fibroblasts. The mycophagy effect over A. fumigatus by S. aureus was exacerbated on the limbo-corneal fibroblast monolayer. During fungal-bacterial interactions, it appears that limbo-corneal fibroblasts showed some phagocytic activity, demonstrating tripartite relationships during coinfection.}, } @article {pmid34485075, year = {2021}, author = {Svensson Malchau, K and Tillander, J and Zaborowska, M and Hoffman, M and Lasa, I and Thomsen, P and Malchau, H and Rolfson, O and Trobos, M}, title = {Biofilm properties in relation to treatment outcome in patients with first-time periprosthetic hip or knee joint infection.}, journal = {Journal of orthopaedic translation}, volume = {30}, number = {}, pages = {31-40}, pmid = {34485075}, issn = {2214-031X}, abstract = {BACKGROUND: Periprosthetic joint infections (PJI) are challenging complications following arthroplasty. Staphylococci are a frequent cause of PJI and known biofilm producers. Biofilm formation decreases antimicrobial susceptibility, thereby challenging favourable treatment outcomes. The aims of this study were to characterize the biofilm abilities and antimicrobial susceptibilities of staphylococci causing first-time PJI and correlate them to clinical outcome (infection resolution and recurrence).

METHODS: Reoperations for PJI of the hip or knee between 1st January 2012 to 30th June 2015 performed at the Sahlgrenska University Hospital were identified in a local database. Medical records were reviewed and clinical parameters recorded for patients whose intraoperative bacterial isolates had been stored at the clinical laboratory. Staphylococcal strains isolated from reoperations due to first-time PJI were characterised by their ability to form biofilms using the microtiter plate test. Antimicrobial susceptibility of the strains was determined by minimum inhibitory concentration (MIC) when grown planktonically, and by minimum biofilm eradication concentration (MBEC) when grown as biofilms. MBEC determination was conducted using the Calgary biofilm device (CBD) and a custom-made antimicrobial susceptibility plate containing eight clinically relevant antimicrobial agents.

RESULTS: The study group included 49 patients (70 bacterial strains) from first-time PJI, whereof 24 (49%) patients had recurrent infection. Strong biofilm production was significantly associated with recurrent infection. Patients infected with strong biofilm producers had a five-fold increased risk for recurrent infection. Strains grown as biofilms were over 8000 times more resistant to antimicrobial agents compared to planktonic cultures. Biofilms were more susceptible to rifampicin compared to other antimicrobials in the assay. Increased biofilm susceptibility (MBEC ​> ​MIC) was observed for the majority of the bacterial strains and antimicrobial agents.

CONCLUSIONS: Strong biofilm production was significantly associated with increased antimicrobial resistance and PJI recurrence. This underscores the importance of determining biofilm production and susceptibility as part of routine diagnostics in PJI. Strong staphylococcal biofilm production may have implications on therapeutic choices and suggest more extensive surgery. Furthermore, despite the increased biofilm resistance to rifampicin, results from this study support its use in staphylococcal PJI.

Like for many biomaterial-associated infections, staphylococci are a common cause of PJI. Their ability to adhere to surfaces and produce biofilms on medical devices is proposed to play a role. However, clinical studies where biofilm properties are directly linked to patient outcome are scarce. This study demonstrates that the majority of staphylococci isolated from first-time PJI were biofilm producers with increased antimicrobial resistance. Patients suffering an infection caused by a staphylococcal strain with strong biofilm production ability had a five-fold greater risk of recurrent infection. This novel finding suggests the importance of evaluating biofilm production as a diagnostic procedure for the guidance of treatment decisions in PJI.}, } @article {pmid34484613, year = {2021}, author = {Liao, MH and Wang, XR and Hsu, WL and Tzen, JTC}, title = {Pu'er tea rich in strictinin and catechins prevents biofilm formation of two cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus.}, journal = {Journal of dental sciences}, volume = {16}, number = {4}, pages = {1331-1334}, pmid = {34484613}, issn = {2213-8862}, abstract = {Cariogenic bacteria, such as Streptococcus mutans and Streptococcus sobrinus, are main pathogens responsible for human dental caries. Pu'er tea is empirically observed to prevent tooth decay. Besides caffeine and catechins commonly found in oolong tea, strictinin is also found as an abundant phenolic compound in Pu'er tea. Infusion of Pu'er tea as well as single compound, strictinin, caffeine or (-)-epigallocatechin gallate (EGCG) was examined for its inhibitory effects on S. mutans and S. sobrinus. Relatively weak inhibition of bacterial growth was observed for these Pu'er tea constituents. However, biofilm formation of S. mutans or S. sobrinus was strongly prevented by the infusion of Pu'er tea as well as by strictinin or EGCG, but not caffeine. Relatively, strictinin showed a higher potency than EGCG to prevent biofilm formation. Anti-caries effect of Pu'er tea seems to be resulted from the prevention of biofilm formation of cariogenic bacteria mainly by strictinin and catechins.}, } @article {pmid34482605, year = {2021}, author = {Huang, Z and Dai, H and Zhang, X and Wang, Q and Sun, J and Deng, Y and Shi, P}, title = {BSC2 induces multidrug resistance via contributing to the formation of biofilm in Saccharomyces cerevisiae.}, journal = {Cellular microbiology}, volume = {23}, number = {12}, pages = {e13391}, doi = {10.1111/cmi.13391}, pmid = {34482605}, issn = {1462-5822}, support = {2232021G-04//Fundamental Research Funds for the Central Universities/ ; 2021-ZJ-Y14//Qinghai Provincial Key Laboratory of Qinghai-Tibet Plateau Biological Resources/ ; }, mesh = {Biofilms ; Drug Resistance, Multiple ; Flocculation ; Membrane Glycoproteins ; *Saccharomyces cerevisiae/genetics ; *Saccharomyces cerevisiae Proteins/genetics ; }, abstract = {Biofilm plays an important role in fungal multidrug resistance (MDR). Our previous studies showed that BSC2 is involved in resistance to amphotericin B (AMB) through antioxidation in Saccharomyces cerevisiae. In this study, the overexpression of BSC2 and IRC23 induced strong MDR in S. cerevisiae. BSC2-overexpression affected cellular flocculation, cell surface hydrophobicity, biofilm formation and invasive growth. However, it failed to induce caspofungin (CAS) resistance and affect the invasive growth in FLO mutant strains (FLO11Δ, FLO1Δ, FLO8Δ and TUP1Δ). Furthermore, the overexpression of BSC2 compensated for chitin synthesis defects to maintain the cell wall integrity and significantly reduced the cell morphology abnormality induced by CAS. However, it could not repair the cell wall damage caused by CAS in the FLO mutant strains. Although BSC2 overexpression increased the level of mannose in the cell wall, DPM1 overexpression in both BY4741 and bsc2∆ could confer resistance to CAS and AMB. In addition, BSC2 overexpression significantly increased the mRNA expression of FLO11, FLO1, FLO8 and TUP1. BSC2 may function as a regulator of FLO genes and be involved in cell wall integrity in yeast. Taken together, our data demonstrate that BSC2 induces MDR in a FLO pathway-dependent manner via contributing to the formation of biofilms in S. cerevisiae. TAKE AWAYS: Overexpression of BSC2 induced strong MDR in S. cerevisiae. BSC2 affected cellular flocculation, CSH, biofilm formation and invasive growth. BSC2 could not repair the cell wall damage caused by CAS in the FLO mutants. BSC2 may function as a regulator of FLO genes to maintain cell wall integrity. BSC2 promotes biofilm formation in a FLO pathway-dependent manner to induce MDR.}, } @article {pmid34482564, year = {2021}, author = {Watari, S and Wada, K and Araki, M and Sadahira, T and Ousaka, D and Oozawa, S and Nakatani, T and Imai, Y and Kato, J and Kariyama, R and Watanabe, T and Nasu, Y}, title = {Intraluminal diamond-like carbon coating with anti-adhesion and anti-biofilm effects for uropathogens: A novel technology applicable to urinary catheters.}, journal = {International journal of urology : official journal of the Japanese Urological Association}, volume = {28}, number = {12}, pages = {1282-1289}, pmid = {34482564}, issn = {1442-2042}, support = {19K18585//Grant-in-Aid for Early Career Scientists/ ; //Ministry of Education, Culture, Sports, Science and Technology, Japan/ ; }, mesh = {Biofilms ; *Carbon ; Coated Materials, Biocompatible/pharmacology ; Technology ; *Urinary Catheters ; }, abstract = {OBJECTIVES: To examine anti-adhesion and anti-biofilm effects of a diamond-like carbon coating deposited via a novel technique on the inner surface of a thin silicon tube.

METHODS: Diamond-like carbon coatings were deposited into the lumen of a silicon tube with inner diameters of 2 mm. The surface of the diamond-like carbon was evaluated using physicochemical methods. We used three clinical isolates including green fluorescent protein-expressing Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. We employed a continuous flow system for evaluation of both bacterial adhesion and biofilm formation. Bacterial adhesion assays consisted of counting the number of colony-forming units and visualization of adhered bacterial cells by scanning electron microscope to evaluate the diamond-like carbon-coated/uncoated samples. The biofilm structure was analyzed by confocal laser scanning microscopy on days 3, 5, 7 and 14 for green fluorescent protein-expressing Pseudomonas aeruginosa.

RESULTS: The smooth and carbon-rich structure of the intraluminal diamond-like carbon film remained unchanged after the experiments. The numbers of colony-forming units suggested lower adherence of green fluorescent protein-expressing Pseudomonas aeruginosa and Escherichia coli in the diamond-like carbon-coated samples compared with the uncoated samples. The scanning electron microscope images showed adhered green fluorescent protein-expressing Pseudomonas aeruginosa cells without formation of microcolonies on the diamond-like carbon-coated samples. Finally, biofilm formation on the diamond-like carbon-coated samples was lower until at least day 14 compared with the uncoated samples.

CONCLUSIONS: Intraluminal diamond-like carbon coating on a silicone tube has anti-adhesion and anti-biofilm effects. This technology can be applied to urinary catheters made from various materials.}, } @article {pmid34481121, year = {2021}, author = {Eze, EC and El Zowalaty, ME and Pillay, M}, title = {Antibiotic resistance and biofilm formation of Acinetobacter baumannii isolated from high-risk effluent water in tertiary hospitals in South Africa.}, journal = {Journal of global antimicrobial resistance}, volume = {27}, number = {}, pages = {82-90}, doi = {10.1016/j.jgar.2021.08.004}, pmid = {34481121}, issn = {2213-7173}, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; South Africa ; Tertiary Care Centers ; Water/pharmacology ; }, abstract = {OBJECTIVES: Discharge of drug-resistant, biofilm-forming pathogens from hospital effluent water into municipal wastewater treatment plants poses a public health concern. This study examined the relationship between antibiotic resistance levels and biofilm formation of Acinetobacter baumannii strains isolated from hospital effluents.

METHODS: Antibiotic susceptibility of 71 A. baumannii isolates was evaluated by the Kirby-Bauer disk diffusion method. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method, while the minimum biofilm eradication concentration (MBEC) was determined by the broth dilution method. Genotyping was performed for plasmid DNA. Biofilm formation was evaluated by the microtitre plate method and was quantified using crystal violet. A P-value of <0.05 was regarded as statistically significant in all tests.

RESULTS: Extensively drug-resistant (XDR) strains made up 58% of the isolates, while multidrug-resistant (MDR) and pandrug-resistant (PDR) strains made up 50% of the isolates from final effluent. The MBEC of ciprofloxacin increased by 255-fold, while that of ceftazidime was as high as 63-1310-fold compared with their respective MICs. Isolates were classified into four plasmid pattern groups with no association between biofilm formation and plasmid type (P = 0.0921). The degree of biofilm formation was independent of the level of antibiotic resistance, although MDR, XDR and PDR isolates produced significant biofilm biomass (P = 0.2580).

CONCLUSION: These results suggest that hospital effluent is a potential source of MDR biofilm-forming A. baumannii strains. Appropriate treatment and disposal of effluents are essential to prevent the presence of drug-resistant pathogens in wastewater.}, } @article {pmid34480246, year = {2021}, author = {Joshi, K and Navalgund, L and Rathod, K and Shet, VB and Srinikethan, G and Shet, T and Rachitha, U and Anand, A}, title = {Biofilm characterization in removal of total chemical oxygen demand and nitrate from wastewater using draft tube spouted bed reactor.}, journal = {Biotechnology letters}, volume = {43}, number = {10}, pages = {2001-2009}, pmid = {34480246}, issn = {1573-6776}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; *Extracellular Polymeric Substance Matrix/chemistry/metabolism ; Nitrates/*isolation & purification/metabolism ; Oxygen/*metabolism ; Wastewater/*chemistry ; }, abstract = {The present paper investigates the effect of dilution rate on the removal of total chemical oxygen demand and nitrate in the draft tube spouted bed reactor and morphological characteristics of biofilms formed by microorganisms of mixed culture on granular activated carbon (GAC). The nitrate and total chemical oxygen demand (COD) decreased from 97 to 81% and 95% to 87% respectively with increase in dilution rate from 0.6/h to 1.5/h showing that residence time in the reactor governs the nitrate and total COD reduction efficiency. Lower dilution rates favor higher production of biomass and extracellular polymeric substances (EPS). It was observed that the nitrate and total COD reduction rate increased with time along with simultaneous increase in EPS production. Thus, the performance of a reactor in terms of dynamic and steady-state biofilm characteristics associated with nitrate and organic reduction is a strong function of dilution rate. Hence these findings indicate that a draft tube spouted bed reactor is capable of simultaneously reducing total organics and nitrogen in industrial/municipal wastewater, as this reactor possesses two distinct regions aerobic and anoxic conditions which can prevail in different parts of a reactor.}, } @article {pmid34479647, year = {2021}, author = {Toledo-Silva, B and de Souza, FN and Mertens, K and Piepers, S and Haesebrouck, F and De Vliegher, S}, title = {Bovine-associated non-aureus staphylococci suppress Staphylococcus aureus biofilm dispersal in vitro yet not through agr regulation.}, journal = {Veterinary research}, volume = {52}, number = {1}, pages = {114}, pmid = {34479647}, issn = {1297-9716}, support = {G0H2516N (AUGE/15/05)//fonds wetenschappelijk onderzoek/ ; }, mesh = {Animals ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Cattle ; Cattle Diseases/*microbiology ; *Quorum Sensing ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus/*physiology ; Staphylococcus aureus/physiology ; Trans-Activators/*metabolism ; }, abstract = {Biofilm formation is a significant virulence factor in Staphylococcus (S.) aureus strains causing subclinical mastitis in dairy cows. A role of environmental signals and communication systems in biofilm development, such as the agr system in S. aureus, is suggested. In the context of multispecies biofilm communities, the presence of non-aureus staphylococci (NAS) might influence S. aureus colonization of the bovine mammary gland, yet, such interspecies interactions have been poorly studied. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices (TA) were able to affect biofilm formation and dispersion of S. aureus, and if so, how isolate traits such as the capacity to regulate the S. aureus agr quorum sensing system are determinants in this process. The capacity of an agr-positive S. aureus strain to form biofilm was increased more in the presence of S. chromogenes than in the presence of S. simulans and S. epidermidis isolates and in the presence of NAS isolates that do not harbor biofilm related genes. On the other hand, biofilm dispersion of this particular S. aureus strain was suppressed by NAS as a group, an effect that was more pronounced by isolates from TA. Furthermore, the observed effects on biofilm formation and dispersion of the agr-positive S. aureus strain as well as of an agr-negative S. aureus strain did not depend on the capacity of NAS to repress the agr system.}, } @article {pmid34478899, year = {2021}, author = {Ghazi, M and Pourhajibagher, M and Bahador, A and Chiniforush, N and Dadpour, S and Dadpour, Y}, title = {Evaluation of adding nanosized natural zeolite to photodynamic therapy against P. gingivalis biofilm on titanium disks.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {36}, number = {}, pages = {102519}, doi = {10.1016/j.pdpdt.2021.102519}, pmid = {34478899}, issn = {1873-1597}, mesh = {Biofilms ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Titanium/pharmacology ; *Zeolites/pharmacology ; }, abstract = {BACKGROUND: Antibacterial photodynamic therapy (aPDT) can be used as an adjunctive therapy for eliminating bacterial biofilm. The application of nanotechnology in aPDT, which is a growing trend, has improved the delivery of photosensitizers (PSs) into microorganisms. Encapsulation of molecules and ions is considered an outstanding potential feature of zeolites. This study sought to enhance the effect of aPDT using a diode laser (810 nm) with a potential PS, indocyanine green (ICG), combined with nanosized natural zeolite (NZ), against biofilm of P. gingivalis on sandblasted, large-grit, and acid-etched (SLA) implant titanium disks surface.

METHODS: A bacterial suspension of standard P. gingivalis (™ATCC® 33277) strains was prepared. To prepare bacterial biofilm, the titanium disks were added to 48 microtubes containing bacterial suspension, and divided into eight groups, i.e., the control groups (positive and negative), and 6 test groups (ICG; NZ; Diod laser; NZ+ICG; aPDT; NZ+aPDT). After the treatments, the total number of colony-forming units per disk was calculated. Finally, the data was analyzed, and the eight groups were compared together.

RESULTS: The highest reduction in the number of P. gingivalis was seen in group 8 (NZ+aPDT) with 3.55 log10 CFU/ml and the antibacterial effect of 45.7% compared with the negative control group. Conversley, group 5 (Diode Laser solely) represented the highest mean of colony count with the lowest antibacterial effects per disk (6.42 log10 CFU/ml, 1.8%).

CONCLUSIONS: The antibacterial effect of NZ+aPDT against P. gingivalis biofilm was noticeable. Thus, adding NZ to ICG improved the result of aPDT in this study.}, } @article {pmid34475672, year = {2021}, author = {Garg, A and Mala, K and Kamath, PM}, title = {Biofilm models in endodontics-A narrative review.}, journal = {Journal of conservative dentistry : JCD}, volume = {24}, number = {1}, pages = {2-9}, pmid = {34475672}, issn = {0972-0707}, abstract = {The knowledge of biofilm and its eradication from the root canal system are of utmost importance in the clinical practice of an endodontist. Various treatment strategies and protocols have been demonstrated and discussed by numerous clinicians and researchers, on these models, that play an important role in the treatment outcome . Once a biofilm model is developed by considering various factors, several methods can be used to assess the biofilms formed on these models. This review discusses the importance of biofilm models in endodontics, types of biofilm models and factors associated with developing and the methods to evaluate these models.}, } @article {pmid34474869, year = {2021}, author = {Song, X and Liu, P and Liu, X and Wang, Y and Wei, H and Zhang, J and Yu, L and Yan, X and He, Z}, title = {Dealing with MDR bacteria and biofilm in the post-antibiotic era: Application of antimicrobial peptides-based nano-formulation.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {128}, number = {}, pages = {112318}, doi = {10.1016/j.msec.2021.112318}, pmid = {34474869}, issn = {1873-0191}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Antimicrobial Cationic Peptides/pharmacology ; Bacteria ; Biofilms ; Pore Forming Cytotoxic Proteins ; }, abstract = {The rapid development of multidrug-resistant (MDR) bacteria due to the improper and overuse of antibiotics and the ineffective performance of antibiotics against the difficult-to-treat biofilm-related infections (BRIs) have urgently called for alternative antimicrobial agents and strategies in combating bacterial infections. Antimicrobial peptides (AMPs), owing to their compelling antimicrobial activity against MDR bacteria and BRIs without causing bacteria resistance, have attracted extensive attention in the research field. With the development of nanomaterial-based drug delivery strategies, AMPs-based nano-formulations have significantly improved the therapeutic effects of AMPs by ameliorating their hydrolytic stability, half-life in vivo, and solubility as well as reducing the cytotoxicity and hemolysis, etc. This review has comprehensively summarized the application AMPs-based nano-formulation in various bacterial infections models, including bloodstream infections (specifically sepsis), pulmonary infections, chronic wound infections, gastrointestinal infections, among others. The design of the nanomaterial-based drug delivery systems and the therapeutic effects of the AMPs-based nano-formulations in literature have been categorized and in details discussed. Overall, this review provides insights into the advantages and disadvantages of the current developed AMPs-based nano-formulations in literature for the treatment of bacterial infections, bringing inspirations and suggestions for their future design in the way towards clinical translation.}, } @article {pmid34474857, year = {2021}, author = {Qiu, G and Wu, H and Huang, M and Ma, T and Schneider, A and Oates, TW and Weir, MD and Xu, HHK and Zhao, L}, title = {Novel calcium phosphate cement with biofilm-inhibition and platelet lysate delivery to enhance osteogenesis of encapsulated human periodontal ligament stem cells.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {128}, number = {}, pages = {112306}, pmid = {34474857}, issn = {1873-0191}, support = {R21 DE029611/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; Calcium Phosphates/pharmacology ; Cell Differentiation ; Cells, Cultured ; Humans ; *Osteogenesis ; *Periodontal Ligament ; Staphylococcus aureus ; Stem Cells ; }, abstract = {Osteomyelitis is caused by Staphylococcus aureus (S. aureus), with associated progressive bone loss. This study developed for the first time a calcium phosphate cement (CPC) for delivery of doxycycline (DOX) and human platelet lysate (hPL) to fight against S. aureus infection and enhance the osteogenesis of human periodontal ligament stem cells (hPDLSCs). Chitosan-containing CPC scaffolds were fabricated in the absence (CPCC) or presence of DOX (CPCC+DOX). In addition, hPL was encapsulated in alginate microbeads and incorporated into CPCC+DOX (CPCC+DOX+ hPL). Flexural strength of CPCC+DOX + hPL was (5.56 ± 0.55) MPa, lower than (8.26 ± 1.6) MPa of CPCC+DOX (p < 0.05), but exceeding the reported strength of cancellous bone. CPCC+DOX and CPCC+DOX + hPL exhibited strong antibacterial activity against S. aureus, reducing biofilm CFU by 4 orders of magnitude. The hPDLSCs encapsulated in microbeads were co-cultured with the CPCs. The hPDLSCs were able to be released from the microbeads and showed a high proliferation rate, increasing by about 8 folds at 14 days for all groups. The hPL was released from the scaffold and promoted the osteogenic differentiation of hPDLSCs. ALP activity was 28.07 ± 5.15 mU/mg for CPCC+DOX + hPL, higher than 17.36 ± 2.37 mU/mg and 1.34 ± 0.37 mU/mg of CPCC+DOX and CPCC, respectively (p < 0.05). At 7 days, osteogenic genes (ALP, RUNX2, COL-1, and OPN) in CPCC+DOX + hPL were 3-10 folds those of control. The amount of hPDLSC-synthesized bone mineral with CPCC+DOX + hPL was 3.8 folds that of CPCC (p < 0.05). In summary, the novel CPC + DOX + hPL-hPDLSCs scaffold exhibited strong antibacterial activity, excellent cytocompatibility and hPDLSC osteogenic differentiation, showing a promising approach for treatment and prevention of bone infection and enhancement of bone regeneration.}, } @article {pmid34474848, year = {2021}, author = {Mendhi, J and Ramachandra, SS and Prasadam, I and Ivanovski, S and Yang, Y and Xiao, Y}, title = {Endogenous nitric oxide-generating surfaces via polydopamine-copper coatings for preventing biofilm dispersal and promoting microbial killing.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {128}, number = {}, pages = {112297}, doi = {10.1016/j.msec.2021.112297}, pmid = {34474848}, issn = {1873-0191}, mesh = {Animals ; Biofilms ; Coated Materials, Biocompatible/pharmacology ; *Copper/pharmacology ; Indoles ; *Nitric Oxide ; Polymers ; Sheep ; Surface Properties ; Titanium/pharmacology ; }, abstract = {INTRODUCTION: Peri-implantitis is a bacterially induced inflammatory disease which affects the hard and soft tissues around a dental implant. Microbial biofilm formation is an important causative factor in peri-implantitis. The aim of this study is to develop an effective multifunctional surface coating for antimicrobial property and to counteract oral biofilm-associated infections via a single polydopamine copper coating (PDAM@Cu) on titanium implant surface to regulate endogenous nitric oxide (NO) generation.

METHODS: PDAM@Cu coatings were made with different concentrations of CuCl2 on titanium surfaces with a simple dip coating technique. Coatings were characterised to evaluate Cu concentrations as well as NO release rates from the coatings. Further, salivary biofilms were made on the coatings using Brain Heart Infusion (BHI) media in an anaerobic chamber. Biofilms were prepared with three different mixtures, one of which was saliva only, the second had an addition of sheep's blood, and the third was prepared with NO donors S-nitrosoglutathione (GSNO) and L-glutathione (GSH) in the mixture of saliva and blood to evaluate the effects of endogenously produced NO on biofilms. The effectiveness of coated surfaces on biofilms were assessed using four different methods, namely, crystal violet assay, scanning electron microscopy imaging, 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) metabolic assay, and live/dead staining.

RESULTS: NO release rates could be controlled with different Cu concentration in PDAM@Cu coatings. NO generated from the PDAM@Cu coatings effectively induced dispersal of biofilms shown by the reduction in biofilm biomass as well as reduced biofilm attachment in samples prepared with blood and NO donors. Cu ions released from the PDAM@Cu coatings resulted in killing of the dispersed bacteria, which was evidenced by the live/dead cell staining and reduced metabolic activity noted from the XTT assay. In contrast, samples prepared with saliva showed no significant reduction in biofilms, indicating the important effect of endogenously generated NO on biofilm dispersal.

CONCLUSION: In conclusion, PDAM@Cu coatings with NO generating surfaces have a dual anti-biofilm function, with a synergistic effect on biofilm dispersal from regulated NO generation and bactericidal effects from Cu ions from the coatings.}, } @article {pmid34473354, year = {2021}, author = {Leelapornpisid, W and Novak-Frazer, L and Qualtrough, A and Rautemaa-Richardson, R}, title = {Effectiveness of D,L-2-hydroxyisocaproic acid (HICA) and alpha-mangostin against endodontopathogenic microorganisms in a multispecies bacterial-fungal biofilm in an ex vivo tooth model.}, journal = {International endodontic journal}, volume = {54}, number = {12}, pages = {2243-2255}, doi = {10.1111/iej.13623}, pmid = {34473354}, issn = {1365-2591}, mesh = {*Biofilms ; Caproates ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; Root Canal Irrigants ; *Xanthones/pharmacology ; }, abstract = {AIM: To develop a defined multispecies root canal biofilm model ex vivo, and to perform viable compositional analysis following D,L-2-hydroxyisocaproic acid (HICA), alpha-mangostin, Calcicur[®] , and Odontopaste[®] exposure.

METHODOLOGY: Time-kill assays were conducted in vitro using HICA, alpha-mangostin, Calcicur[®] , Odontopaste[®] , and saline solution on the planktonic cultures of C. albicans, E. faecalis, L. rhamnosus, and S. gordonii. Human root dentine blocks were prepared (n = 100) ex vivo, and multispecies suspensions containing each of 1.5 × 10[8]  CFU/mL C. albicans, E. faecalis, L. rhamnosus, and S. gordonii in brain heart infusion (BHI) were incubated within the root canals for 21 days. Canals (n = 20/group) were then exposed to medicaments for 7 days. Samples taken from the inner (first 0.1 mm) and deeper (second 0.1 mm) dentine by drilling with Ash Steel Burs No. 5 and No. 6, and residual roots were cultured in broth for 24 h. Cell growth was detected by spectrophotometry and confirmed by culture on agar. The other set of inner dentine, deeper dentine, and residual root samples were sonicated, and then exposed with 50 μM PMA before DNA was extracted using the QIAamp DNA mini kit. Real-time quantitative PCR was performed to determine the biofilm composition as well as the number of live and total cells remaining in the biofilm following each treatment. The OD data were analysed with Kruskal-Wallis and Friedman with Wilcoxon signed-rank test between and within groups, respectively, agar culture and qPCR data with Pearson chi-square with Mann-Whitney and Cochran with McNemar tests, respectively (p < .0001).

RESULTS: Time-kill assays revealed that HICA and Calcicur[®] killed all planktonic organisms within 24 h, whilst alpha-mangostin killed the organisms within 72 h. However, Odontopaste[®] was a slow-killing agent: 10 cells of planktonic organisms survived after exposure to the agent for 7 days. The ex vivo tooth model demonstrated that HICA and alpha-mangostin significantly inhibited the cell growth in all sampling depths (p < .0001). All species-specific data revealed the effectiveness of each medicament on the biofilm composition.

CONCLUSIONS: D,L-2-hydroxyisocaproic acid and alpha-mangostin had antimicrobial activity against multispecies bacterial-fungal biofilms.}, } @article {pmid34469193, year = {2021}, author = {Hashidoko, Y and Kim, D}, title = {Bidirectional Cell-Cell Communication via Indole and Cyclo(Pro-Tyr) Modulates Interspecies Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {22}, pages = {e0127721}, pmid = {34469193}, issn = {1098-5336}, mesh = {Biofilms/*growth & development ; *Burkholderiaceae/genetics/physiology ; Dipeptides/*metabolism ; *Escherichia coli/genetics/physiology ; Indoles/*metabolism ; Microbial Interactions ; }, abstract = {The extracellular signaling molecule indole plays a pivotal role in biofilm formation by the enteric gammaproteobacterium Escherichia coli; this process is particularly correlated with the extracellular indole concentration. Using the indole-biodegrading betaproteobacterium Burkholderia unamae, we examined the mechanism by which these two bacteria modulate biofilm formation in an indole-dependent manner. We quantified the spatial organization of cocultured microbial communities at the micrometer scale through computational image analysis, ultimately identifying how bidirectional cell-to-cell communication modulated the physical relationships between them. Further analysis allowed us to determine the mechanism by which the B. unamae-derived signaling diketopiperazine cyclo(Pro-Tyr) considerably upregulated indole biosynthesis and enhanced E. coli biofilm formation. We also determined that the presence of unmetabolized indole enhanced the production of cyclo(Pro-Tyr). Thus, bidirectional cell-to-cell communication that occurred via interspecies signaling molecules modulated the formation of a mixed-species biofilm between indole-producing and indole-consuming species. IMPORTANCE Indole is a relatively stable N-heterocyclic aromatic compound that is widely found in nature. To date, the correlations between indole-related bidirectional cell-to-cell communications and interspecies communal organization remain poorly understood. In this study, we used an experimental model, which consisted of indole-producing and indole-degrading bacteria, to evaluate how bidirectional cell-to-cell communication modulated interspecies biofilm formation via intrinsic and environmental cues. We identified a unique spatial patterning of indole-producing and indole-degrading bacteria within mixed-species biofilms. This spatial patterning was an active process mediated by bidirectional physicochemical interactions. Our findings represent an important step in gaining a more thorough understanding of the process of polymicrobial biofilm formation and advance the possibility of using indole-degrading bacteria to address biofilm-related health and industry issues.}, } @article {pmid34469136, year = {2021}, author = {Liu, M and Han, P and Zhang, L and Zhong, C and You, C}, title = {Biofilm-Mediated Immobilization of a Multienzyme Complex for Accelerating Inositol Production from Starch.}, journal = {Bioconjugate chemistry}, volume = {32}, number = {9}, pages = {2032-2042}, doi = {10.1021/acs.bioconjchem.1c00338}, pmid = {34469136}, issn = {1520-4812}, mesh = {*Biofilms ; *Enzymes, Immobilized ; *Inositol ; Starch ; }, abstract = {Bacterial biofilm, as a natural and renewable material, is a promising architecture for enzyme immobilization. In this study, we have demonstrated the feasibility of an Escherichia coli biofilm to immobilize a self-assembly multienzyme complex by the covalent interaction between a peptide SpyTag and its protein partner SpyCatcher. The SpyTag-labeled biofilm is displayed on the surface of E. coli by overexpressing the recombinant CsgA-SpyTag, in which CsgA is capable of forming biofilms. This SpyTag bearing biofilm is used to bind with SpyCatcher bearing synthetic mini-scaffoldin, which also contains a carbohydrate-binding module 3 (CBM3), and four different cohesins from different microorganisms. CBM3 was used to bind with cellulose, while the four different cohesins were used to recruit four dockerin-containing cascade enzymes, which were subsequently applied to convert starch to myo-inositol. Compared to the free enzyme mixture, the biofilm-immobilized enzyme complex exhibited a 4.28 times increase in initial reaction rate in producing myo-inositol from 10 g/L maltodextrin (a derivative of starch). Additionally, this biofilm-immobilized enzyme complex showed much higher recycle ability than the enzyme complex which was immobilized on a regenerated amorphous cellulose (RAC) system. In conclusion, the biofilm-mediated immobilization of the enzymatic biosystem provides a promising strategy to increase the reaction rate and enhance the stability of an in vitro enzymatic biosystem, exhibiting high potential to improve the efficiency of an in vitro biosystem.}, } @article {pmid34466092, year = {2021}, author = {El-Tarabily, KA and El-Saadony, MT and Alagawany, M and Arif, M and Batiha, GE and Khafaga, AF and Elwan, HAM and Elnesr, SS and E Abd El-Hack, M}, title = {Using essential oils to overcome bacterial biofilm formation and their antimicrobial resistance.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {9}, pages = {5145-5156}, pmid = {34466092}, issn = {1319-562X}, abstract = {The increase of resistant bacteria puts a huge pressure on the antimicrobials in current use. Antimicrobial resistance (AMR) results from antibiotic misuse and abuse over many years and is a global financial burden. New polices must be developed for the use of antimicrobials and to continue research efforts to mitigate AMR. It is essential to target the most harmful bacteria and concentrate on their mechanisms of resistance to develop successful antimicrobials. Essential oils (EOs) are occur naturally in plants and have long been used as antimicrobials, but most have not been researched. This review explores EOs as alternative antimicrobials, investigating their ability to decrease or inhibit biofilm formation, and assess their ability to contribute to AMR control. Low concentrations of EOs can inhibit Gram-positive and Gram-negative pathogenic bacteria. Some EOs have demonstrated strong anti-biofilm activities. If EOs are successful against biofilm formation, particularly in bacteria developing AMR, they could be incorporated into new antimicrobials. Therefore, there is a need to investigate these EOs' potential, particularly for surface disinfection, and against bacteria from food, clinical and non-clinical environments.}, } @article {pmid34466074, year = {2021}, author = {Alarjani, KM and Almutairi, AM and Flanet Raj, SR and Rajaselvam, J and Chang, SW and Ravindran, B}, title = {Biofilm producing indigenous bacteria isolated from municipal sludge and their nutrient removal ability in moving bed biofilm reactor from the wastewater.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {9}, pages = {4994-5001}, pmid = {34466074}, issn = {1319-562X}, abstract = {In the present study, improved moving bed biofilm reactor (MBBR) was applied to enhance the nutrient removal ability of the municipal wastewater. A total of 18 indigenous bacterial isolates were screened from the sewage sludge sample and nitrate reductase, nitrite reductase and hydroxylamine oxidase was analyzed. The strains Pseudomonas aeruginosa NU1 and Acinetobacter calcoaceticus K12 produced 0.87 ± 0.05 U/mg and 0.52 ± 0.12 U/mg hydroxylamine oxidase, 1.023 ± 0.062 U/mg and 1.29 ± 0.07 U/mg nitrite reductase, and 0.789 ± 0.031 U/mg and 1.07 ± 0.13 U/mg nitrate reductase. Nitrogen and phosphate removal improved by the addition of nutrient sources and achieved > 80% removal rate. pH and temperature of the medium also affected nutrient removal and improved removal was achieved at optimum level (p < 0.05). MBBR was designed with R1 (aerobic), R2 and R3 (anoxic) reactors. MBBR reactors removed acceptable level phosphorus removal properties up to 7.2 ± 3.8%, 42.4 ± 4.6%, and 84.2 ± 13.1% in the R1, R2, R3 and R4 reactors, respectively. Denitrification rate showed linear relationship at increasing concentrations nitrogen content in the reactor and denitrification rate was 1.43 g NO2-N /m[2]/day at 1.5 g NO2-N /m[2]/day. Dehydrogenase activity was assayed in all reactors and maximum amount was detected in the aerobic biofilm reactor. Based on the present findings, MBBRs and the selected bacterial strains are useful for the degradation domestic wastewater with minimum working area.}, } @article {pmid34464080, year = {2021}, author = {Motealleh, A and Kart, D and Czieborowski, M and Kehr, NS}, title = {Functional Nanomaterials and 3D-Printable Nanocomposite Hydrogels for Enhanced Cell Proliferation and for the Reduction of Bacterial Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {36}, pages = {43755-43768}, doi = {10.1021/acsami.1c13392}, pmid = {34464080}, issn = {1944-8252}, mesh = {Alginates/chemistry ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Cell Line ; Cell Proliferation/drug effects ; Drug Carriers/chemical synthesis/*chemistry ; Drug Liberation ; Enterococcus faecalis/drug effects/physiology ; Humans ; Hydrogels/*chemistry ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests ; Multifunctional Nanoparticles/*chemistry ; Nanocomposites/chemistry ; Polylysine/chemistry ; Porosity ; Pseudomonas aeruginosa/drug effects/physiology ; Silicon Dioxide/chemistry ; Staphylococcus aureus/drug effects/physiology ; Tetracycline/chemistry/*pharmacology ; }, abstract = {Biomaterial-associated infections are a major cause of biomaterial implant failure. To prevent the initial attachment of bacteria to the implant surface, researchers have investigated various surface modification methods. However, most of these approaches also prevent the attachment, spread, and growth of mammalian cells, resulting in tissue integration failure. Therefore, the success of biomaterial implants requires an optimal balance between tissue integration (cell adhesion to biomaterial implants) and inhibition of bacterial colonization. In this regard, we synthesize bifunctional nanomaterials by functionalizing the pores and outer surfaces of periodic mesoporous organosilica (PMO) with antibacterial tetracycline (Tet) and antibacterial and cell-adhesive bipolymer poly-d-lysine (PDL), respectively. Then, the fabricated [Tet]PMO-PDL nanomaterials are incorporated into alginate-based hydrogels to create injectable and 3D-printable nanocomposite (NC) hydrogels (AlgL-[Tet]PMO-PDL). These bifunctional nanomaterial and 3D-printable NC hydrogel show pH-dependent release of Tet over 7 days. They also enhance the proliferation of eukaryotic cells (fibroblasts). [Tet]PMO-PDL is inactive in reducing Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis biofilms. However, AlgL-[Tet]PMO-PDL shows significant antibiofilm activity against P. aeruginosa. These results suggest that the incorporation of [Tet]PMO-PDL into AlgL may have a synergistic effect on the inhibition of the Gram-negative bacterial (P. aeruginosa) biofilm, while this has no effect on the reduction of the Gram-positive bacterial (S. aureus and E. faecalis) biofilm.}, } @article {pmid34462461, year = {2021}, author = {Pizauro, LJL and de Almeida, CC and Silva, SR and MacInnes, JI and Kropinski, AM and Zafalon, LF and de Avila, FA and de Mello Varani, A}, title = {Genomic comparisons and phylogenetic analysis of mastitis-related staphylococci with a focus on adhesion, biofilm, and related regulatory genes.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {17392}, pmid = {34462461}, issn = {2045-2322}, mesh = {Adhesins, Bacterial/*genetics ; Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cattle ; Female ; Mastitis, Bovine/microbiology/*pathology ; Phylogeny ; Staphylococcal Infections/microbiology/*pathology ; Staphylococcus/classification/*genetics/isolation & purification/physiology ; Transcription Factors/genetics/metabolism ; Virulence Factors/genetics ; }, abstract = {Mastitis is a common and costly disease on dairy farms, commonly caused by Staphylococcus spp. though the various species are associated with different clinical outcomes. In the current study, we performed genomic analyses to determine the prevalence of adhesion, biofilm, and related regulatory genes in 478 staphylococcal species isolated from clinical and subclinical mastitis cases deposited in public databases. The most prevalent adhesin genes (ebpS, atl, pls, sasH and sasF) were found in both clinical and subclinical isolates. However, the ebpS gene was absent in subclinical isolates of Staphylococcus arlettae, S. succinus, S. sciuri, S. equorun, S. galinarum, and S. saprophyticus. In contrast, the coa, eap, emp, efb, and vWbp genes were present more frequently in clinical (vs. subclincal) mastitis isolates and were highly correlated with the presence of the biofim operon (icaABCD) and its transcriptional regulator, icaR. Co-phylogenetic analyses suggested that many of these adhesins, biofilm, and associated regulatory genes could have been horizontally disseminated between clinical and subclinical isolates. Our results further suggest that several adhesins, biofilm, and related regulatory genes, which have been overlooked in previous studies, may be of use for virulence profiling of mastitis-related Staphylococcus strains or as potential targets for vaccine development.}, } @article {pmid34461541, year = {2022}, author = {Luo, H and Liu, C and He, D and Xu, J and Sun, J and Li, J and Pan, X}, title = {Environmental behaviors of microplastics in aquatic systems: A systematic review on degradation, adsorption, toxicity and biofilm under aging conditions.}, journal = {Journal of hazardous materials}, volume = {423}, number = {Pt A}, pages = {126915}, doi = {10.1016/j.jhazmat.2021.126915}, pmid = {34461541}, issn = {1873-3336}, mesh = {Adsorption ; Biofilms ; *Microplastics ; Plastics ; *Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {Microplastics (MPs, < 5 mm) in the environment have attracted worldwide attention due to their wide distribution and difficulty in handling. Aging processes such as UV irradiation, biodegradation, physical abrasion and chemical oxidation can affect the environmental behavior of MPs. This review article summarizes different aging processes of MPs and subsequent effects on the adsorption of pollutants, the leaching of additives, and the toxicity of MPs. In addition, the formation process of biofilm on the surface of MPs and the interactions between biofilm and aged MPs are revealed. MPs can accumulate different environmental pollutants (organic pollutants, heavy metals, microorganisms, etc.) through surface adsorption, pore filling and distribution. Moreover, the aging of MPs affects their adsorption performance toward these pollutants due to a series of changes in their specific surface area and oxygen-containing functional groups. The release of some toxic additives such as phthalates after aging can enhance the toxic effects of MPs. Aging also changes the shape and size of MPs, which can affect the eating habits of the organisms and further increase the potential toxicity of MPs. This article conducts a systematical analysis and summary of the environmental behavior and physicochemical properties of MPs as well as the changes due to MPs aging, which helps to better understand the impact of aging on MPs in the environment. Future research on MPs aging should reduce the knowledge gap between laboratory simulation and actual conditions and increase the environmental relevance.}, } @article {pmid34461310, year = {2021}, author = {Rohatgi, A and Gupta, P}, title = {Natural and synthetic plant compounds as anti-biofilm agents against Escherichia coli O157:H7 biofilm.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {95}, number = {}, pages = {105055}, doi = {10.1016/j.meegid.2021.105055}, pmid = {34461310}, issn = {1567-7257}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Escherichia coli Infections/*drug therapy ; Escherichia coli O157/*drug effects/physiology ; Humans ; Phytochemicals/chemistry/*pharmacology ; }, abstract = {Escherichia coli is a common gram-negative bacterium found in the gut and intestinal tract of warm-blooded animals including humans. An evolved seropathotype E. coli O157:H7 (STEC) came into existence in 1982, since then it has been evolved as a stronger and more robust drug-resistant pathotype of E. coli. This drug resistance is due to horizontal gene transfer, natural gene evolution for survival, and most of the cases due to the ability of STEC to switch to the biofilm growth mode from planktonic lifestyle. During the growth in biofilm mode, Escherichia coli O157:H7 opts more robust ability to grow in adverse environments i.e., in presence of antibiotics and other antimicrobial chemicals. Due to the biofilm matrix, the microbial community acquires drug resistance. This makes the treatment of diseases caused by E. coli O157:H7 a complex challenge. To address the illnesses caused by this biofilm-forming pathogen, there are several possible strategies such as antibiotic therapies, synthetic antimicrobial chemicals, adjunct therapy of synergistic effect of multiple drugs, and more importantly plant originated compounds as a new anti-biofilm candidate. The present review summarizes various phytochemicals and their derivatives reported in the last decade mostly to eliminate the biofilm of STEC. The review will progressively reveal the antibiofilm mechanism of the phytochemicals against STEC and to be a potential candidate for the development of the future antibacterial drugs to STEC induced infections.}, } @article {pmid34460871, year = {2021}, author = {Soh, EY and Smith, F and Gimenez, MR and Yang, L and Vejborg, RM and Fletcher, M and Halliday, N and Bleves, S and Heeb, S and Cámara, M and Givskov, M and Hardie, KR and Tolker-Nielsen, T and Ize, B and Williams, P}, title = {Disruption of the Pseudomonas aeruginosa Tat system perturbs PQS-dependent quorum sensing and biofilm maturation through lack of the Rieske cytochrome bc1 sub-unit.}, journal = {PLoS pathogens}, volume = {17}, number = {8}, pages = {e1009425}, pmid = {34460871}, issn = {1553-7374}, support = {BB/F014392/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 108876/Z/15/Z/WT_/Wellcome Trust/United Kingdom ; 103884/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; MR/N501852/1/MRC_/Medical Research Council/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; DNA, Bacterial/genetics ; Electron Transport Complex III/genetics/*metabolism ; Extracellular Vesicles/*genetics ; Gene Expression Regulation, Bacterial ; Glycolipids/metabolism ; Pseudomonas aeruginosa/drug effects/*growth & development/metabolism ; Pyocyanine/metabolism ; Quinolones/*metabolism ; *Quorum Sensing ; Twin-Arginine-Translocation System/genetics/*metabolism ; Virulence Factors/genetics/metabolism ; }, abstract = {Extracellular DNA (eDNA) is a major constituent of the extracellular matrix of Pseudomonas aeruginosa biofilms and its release is regulated via pseudomonas quinolone signal (PQS) dependent quorum sensing (QS). By screening a P. aeruginosa transposon library to identify factors required for DNA release, mutants with insertions in the twin-arginine translocation (Tat) pathway were identified as exhibiting reduced eDNA release, and defective biofilm architecture with enhanced susceptibility to tobramycin. P. aeruginosa tat mutants showed substantial reductions in pyocyanin, rhamnolipid and membrane vesicle (MV) production consistent with perturbation of PQS-dependent QS as demonstrated by changes in pqsA expression and 2-alkyl-4-quinolone (AQ) production. Provision of exogenous PQS to the tat mutants did not return pqsA, rhlA or phzA1 expression or pyocyanin production to wild type levels. However, transformation of the tat mutants with the AQ-independent pqs effector pqsE restored phzA1 expression and pyocyanin production. Since mutation or inhibition of Tat prevented PQS-driven auto-induction, we sought to identify the Tat substrate(s) responsible. A pqsA::lux fusion was introduced into each of 34 validated P. aeruginosa Tat substrate deletion mutants. Analysis of each mutant for reduced bioluminescence revealed that the primary signalling defect was associated with the Rieske iron-sulfur subunit of the cytochrome bc1 complex. In common with the parent strain, a Rieske mutant exhibited defective PQS signalling, AQ production, rhlA expression and eDNA release that could be restored by genetic complementation. This defect was also phenocopied by deletion of cytB or cytC1. Thus, either lack of the Rieske sub-unit or mutation of cytochrome bc1 genes results in the perturbation of PQS-dependent autoinduction resulting in eDNA deficient biofilms, reduced antibiotic tolerance and compromised virulence factor production.}, } @article {pmid34460313, year = {2021}, author = {Kalamara, M and Stanley-Wall, NR}, title = {The Intertwined Roles of Specialized Metabolites within the Bacillus subtilis Biofilm.}, journal = {Journal of bacteriology}, volume = {203}, number = {22}, pages = {e0043121}, pmid = {34460313}, issn = {1098-5530}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M010996/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Bacillus subtilis ; *Biofilms ; }, abstract = {Bacteria produce specialized metabolites with a range of functions. In this issue of the Journal of Bacteriology, Schoenborn et al. study the production and role of secondary metabolites during biofilm development and sporulation in Bacillus subtilis (A. A. Schoenborn, S. M. Yannarell, E. D. Wallace, H. Clapper, et al., J Bacteriol 203:e00337-21, 2021, https://doi.org/https://doi.org/10.1128/JB.00337-21). Most metabolites studied are produced during differentiation, and six are required for the development of biofilms and/or spores. The authors propose a model for the timing of production and role in differentiation exerted by each secondary metabolite.}, } @article {pmid34459556, year = {2021}, author = {Rørvik, GH and Naemi, AO and Edvardsen, PKT and Simm, R}, title = {The c-di-AMP signaling system influences stress tolerance and biofilm formation of Streptococcus mitis.}, journal = {MicrobiologyOpen}, volume = {10}, number = {4}, pages = {e1203}, pmid = {34459556}, issn = {2045-8827}, mesh = {Acetic Acid/pharmacology ; Adaptation, Physiological/*physiology ; Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Cell Line, Tumor ; Ciprofloxacin/pharmacology ; Cyclic AMP/*metabolism ; Cyclic Nucleotide Phosphodiesterases, Type 1/genetics/metabolism ; Cyclic Nucleotide Phosphodiesterases, Type 2/genetics/metabolism ; Gene Deletion ; Gene Expression Regulation, Bacterial/genetics ; Humans ; Keratinocytes/microbiology ; Mouth/microbiology ; Octoxynol/pharmacology ; Phosphorus-Oxygen Lyases/genetics/metabolism ; Second Messenger Systems/*physiology ; Streptococcus mitis/growth & development/*metabolism ; Stress, Physiological/physiology ; }, abstract = {Streptococcus mitis is a commensal bacterial species of the oral cavity, with the potential for opportunistic pathogenesis. For successful colonization, S. mitis must be able to adhere to surfaces of the oral cavity and survive and adapt to frequently changing environmental conditions. Cyclic-di-AMP (c-di-AMP) is a nucleotide second messenger, involved in the regulation of stress responses and biofilm formation in several bacterial species. Cyclic-di-AMP is produced by diadenylate cyclases and degraded by phosphodiesterases. We have previously shown that in S. mitis, one diadenylate cyclase (CdaA) and at least two phosphodiesterases (Pde1 and Pde2) regulate the intracellular concentration of c-di-AMP. In this study, we utilized S. mitis deletion mutants of cdaA, pde1, and pde2 to analyze the role of c-di-AMP signaling in various stress responses, biofilm formation, and adhesion to eukaryotic cells. Here, we demonstrate that the Δpde1 mutant displayed a tendency toward increased susceptibility to acetic acid at pH 4.0. Deletion of cdaA increases auto-aggregation of S. mitis but reduces biofilm formation on an abiotic surface. These phenotypes are more pronounced under acidic extracellular conditions. Inactivation of pde1 or pde2 reduced the tolerance to ciprofloxacin, and UV radiation and the Δpde1 mutant was more susceptible to Triton X-100, indicating a role for c-di-AMP signaling in responses to DNA damage and cell membrane perturbation. Finally, the Δpde2 mutant displayed a tendency toward a reduced ability to adhere to oral keratinocytes. Taken together, our results indicate an important role for c-di-AMP signaling in cellular processes important for colonization of the mouth.}, } @article {pmid34456739, year = {2021}, author = {Qu, Q and Cui, W and Xing, X and Zou, R and Huang, X and Wang, X and Wu, T and Bello-Onaghise, G and Yuan, S and Li, Y}, title = {Rutin, A Natural Inhibitor of IGPD Protein, Partially Inhibits Biofilm Formation in Staphylococcus xylosus ATCC700404 in vitro and in vivo.}, journal = {Frontiers in pharmacology}, volume = {12}, number = {}, pages = {728354}, pmid = {34456739}, issn = {1663-9812}, abstract = {Staphylococcus xylosus (S. xylosus) has become an emerging opportunistic pathogen due to its strong biofilm formation ability. Simultaneously, the biofilm of bacteria plays an important role in antibiotic resistance and chronic infection. Here, we confirmed that rutin can effectively inhibit biofilm formation in S. xylosus, of which the inhibition mechanism involves its ability to interact with imidazole glycerol phosphate dehydratase (IGPD), a key enzyme in the process of biofilm formation. We designed experiments to target IGPD and inhibited its activities against S. xylosus. Our results indicated that the activity of IGPD and the amount of histidine decreased significantly under the condition of 0.8 mg/ml rutin. Moreover, the expression of IGPD mRNA (hisB) and IGPD protein was significantly down-regulated. Meanwhile, the results from molecular dynamic simulation and Bio-layer interferometry (BLI) technique showed that rutin could bind to IGPD strongly. Additionally, in vivo studies demonstrated that rutin treatment reduced inflammation and protect mice from acute mastitis caused by S. xylosus. In summary, our findings provide new insights into the treatment of biofilm mediated persistent infections and chronic bacterial infections. It could be helpful to design next generation antibiotics to against resistant bacteria.}, } @article {pmid34456615, year = {2021}, author = {Dos Santos, EMP and Martins, CCB and de Oliveira Santos, JV and da Silva, WRC and Silva, SBC and Pelagio-Flores, MA and Galembeck, A and Cavalcanti, IMF}, title = {Silver nanoparticles-chitosan composites activity against resistant bacteria: tolerance and biofilm inhibition.}, journal = {Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology}, volume = {23}, number = {8}, pages = {196}, pmid = {34456615}, issn = {1388-0764}, abstract = {UNLABELLED: This study aimed to evaluate the effectiveness of silver nanoparticles-chitosan composites (AgNPs) with different morphologies and particle size distributions against resistant bacteria and biofilm formation. Four different samples were prepared by a two-step procedure using sodium borohydride and ascorbic acid as reducing agents and characterized by UV-Vis absorption spectra, scanning transmission electron microscopy. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the AgNPs were determined according to the Clinical and Laboratory Standards Institute (CLSI) against clinical isolates multidrug-resistant and strains of the American Type Culture Collection (ATCC). An assay was performed to determine the MICs during 20 successive bacteria exposures to AgNPs to investigate whether AgNPs induce tolerance in bacteria. The antibiofilm activities of AgNPs were also evaluated by determining the minimum biofilm inhibitory concentration (MBIC). The spherical AgNPs present diameters ranging from 9.3 to 62.4 nm, and some samples also have rod-, oval-, and triangle-shaped nanoparticles. The MIC and MBC values ranged from 0.8 to 25 μg/mL and 3.1 to 50 μg/mL, respectively. Smaller and spherical AgNPs exhibited the highest activity, but all the AgNPs developed in this study exhibit bactericidal activity. There was no significant MIC increase after 20 passages to the AgNPs. Regarding the antibiofilm activity, MBICs ranged from 12.5 to 50 μg/mL. Again, smaller and spherical nanoparticles presented the best results with phenotypic inhibition of production of slime or exopolysaccharide (EPS) matrix. Thus, it was concluded that AgNPs have a promising potential against resistant bacteria and bacteria that grow on biofilms without inducing tolerance.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11051-021-05314-1.}, } @article {pmid34455871, year = {2021}, author = {Gilbert-Girard, S and Reigada, I and Savijoki, K and Yli-Kauhaluoma, J and Fallarero, A}, title = {Screening of natural compounds identifies ferutinin as an antibacterial and anti-biofilm compound.}, journal = {Biofouling}, volume = {37}, number = {7}, pages = {791-807}, doi = {10.1080/08927014.2021.1971655}, pmid = {34455871}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Benzoates ; Biofilms ; Bridged Bicyclo Compounds ; Cycloheptanes ; Humans ; Microbial Sensitivity Tests ; Sesquiterpenes ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {Antibacterial screenings are most commonly targeted at planktonic bacteria but less effort is dedicated to the exploration of agents acting on biofilms. Here, a natural compounds library was screened against Staphylococcus aureus using a 384-well plate platform to identify compounds preventing biofilm formation. Five structurally diverse hits were selected for follow-up studies: honokiol, tschimganidin, ferutinin, oridonin and deoxyshikonin. The compounds were evaluated against different bacterial species for their capacity to prevent and disrupt biofilms. The development of resistance and cytotoxicity were also investigated. Ferutinin displayed the best antibacterial activity, with a minimum inhibitory, bactericidal and biofilm preventive concentration of 25 µM against S. aureus. It efficiently disrupted pre-formed biofilms (over 5-log reduction of viable cells) and reduced biofilm formation on a catheter in the presence of neutrophils. This work provides new information on the antibacterial activity of five natural compounds and identified ferutinin as a promising candidate against S. aureus biofilms.}, } @article {pmid34455869, year = {2021}, author = {Talluri, SNL and Winter, RM and Salem, DR}, title = {Nanoscale characteristics of conditioning film development on photobioreactor materials: influence on the initial adhesion and biofilm formation by a cyanobacterium.}, journal = {Biofouling}, volume = {37}, number = {7}, pages = {777-790}, doi = {10.1080/08927014.2021.1971201}, pmid = {34455869}, issn = {1029-2454}, mesh = {*Anabaena ; Bacterial Adhesion ; Biofilms ; *Biofouling/prevention & control ; Microscopy, Atomic Force ; Photobioreactors ; Surface Properties ; }, abstract = {Adsorption of conditioning films on a solid surface is the first step in the development of biofilms. With the goal of understanding the preliminary adhesion mechanisms of cyanobacteria on photobioreactor (PBR) materials to prevent biofouling, the physical changes occurring on PBR materials were investigated during the initial adhesion and biofilm formation by Anabaena sp. PCC 7120, a cyanobacterium that is genetically modified to produce linalool. Atomic force microscopy (AFM) revealed that the conditioning film deposition was in the form of spike-like structures on all the materials except PVC. The average heights (in the range 9 - 16 nm) of the conditioning films deposited on glass, PMMA, PC and HDPE were 11 to 20 times higher than on PVC at 96 h. The time dependent change in thickness of conditioning films correlated well with Anabaena cell attachment to the PBR materials. The rapid and significant colonization of Anabaena on glass within 48 h was consistent with the increase in thickness of the conditioning film within this time period. Lack of the conditioning film spike structures and no change in thickness of the conditioning films with time on the PVC together with comparatively delayed cell attachment and conditioning-film protein deposition on this material, indicated that the nanoscale spike structures on the other PBR materials may be accelerating the cell attachment process but are not a prerequisite for cell attachment. These results suggest that PVC should be explored further as an antifouling material for photobioreactors. The thickness of the conditioning films on glass measured by a scratch and scan method was in good agreement with the thickness values measured by an adhesive tape method, indicating that both these methods can be used for fast and reliable AFM thickness determination of bacterial conditioning films.}, } @article {pmid34455651, year = {2021}, author = {Saïdi, F and Jolivet, NY and Lemon, DJ and Nakamura, A and Belgrave, AM and Garza, AG and Veyrier, FJ and Islam, ST}, title = {Bacterial glycocalyx integrity drives multicellular swarm biofilm dynamism.}, journal = {Molecular microbiology}, volume = {116}, number = {4}, pages = {1151-1172}, doi = {10.1111/mmi.14803}, pmid = {34455651}, issn = {1365-2958}, mesh = {Bacterial Proteins/metabolism ; *Biofilms ; Cell Membrane/metabolism ; Fimbriae, Bacterial/*metabolism ; Glycocalyx/*metabolism ; Myxococcus xanthus/growth & development/*metabolism ; Polysaccharides, Bacterial/*metabolism ; }, abstract = {Exopolysaccharide (EPS) layers on the bacterial cell surface are key determinants of biofilm establishment and maintenance, leading to the formation of higher-order 3D structures that confer numerous survival benefits to a cell community. In addition to a specific cell-associated EPS glycocalyx, we recently revealed that the social δ-proteobacterium Myxococcus xanthus secretes a novel biosurfactant polysaccharide (BPS) to the extracellular milieu. Together, secretion of the two polymers (EPS and BPS) is required for type IV pilus (T4P)-dependent swarm expansion via spatio-specific biofilm expression profiles. Thus the synergy between EPS and BPS secretion somehow modulates the multicellular lifecycle of M. xanthus. Herein, we demonstrate that BPS secretion functionally alters the EPS glycocalyx via destabilization of the latter, fundamentally changing the characteristics of the cell surface. This impacts motility behaviors at the single-cell level and the aggregative capacity of cells in groups via cell-surface EPS fibril formation as well as T4P production, stability, and positioning. These changes modulate the structure of swarm biofilms via cell layering, likely contributing to the formation of internal swarm polysaccharide architecture. Together, these data reveal the manner by which the combined secretion of two distinct polymers induces single-cell changes that modulate swarm biofilm communities.}, } @article {pmid34455348, year = {2021}, author = {Kim, HJ and Park, JS and Lee, TK and Kang, D and Kang, JH and Shin, K and Jung, SW}, title = {Dynamics of marine bacterial biofouling communities after initial Alteromonas genovensis biofilm attachment to anti-fouling paint substrates.}, journal = {Marine pollution bulletin}, volume = {172}, number = {}, pages = {112895}, doi = {10.1016/j.marpolbul.2021.112895}, pmid = {34455348}, issn = {1879-3363}, mesh = {Alteromonas ; Bacteria ; Biofilms ; *Biofouling/prevention & control ; Paint ; }, abstract = {To determine how bacterial communities succeed after the initial attachment of the bacterial biofilm adhesion using 16S rDNA meta-barcoding in plates coated with copper-based anti-fouling (AF) and non-AF (control) coatings as well as ambient seawater, coated plates were submerged in a marine environment in situ. Alteromonas genovensis (Gammaproteobacteria) in AF coating and Pacificibacter sp. (Alphaproteobacteria) in the control plate were initially abundant. In the AF coating, the abundance of A. genovensis decreased rapidly, whereas that of genus Phaeobacter (Alphaproteobacteria), Serratia (Gammaproteobacteria) and Cupriavidus (Betaproteobacteria) increased. Bacterial community in the control plate had a strong connection to pathogenic Vibrio spp. associated with the growth of invertebrates. Therefore, in the in situ AF coating experiment, A. genovensis accumulation was initially and intensively increased, and the bacteria responded to chemical antagonism, induced the proliferation of specific biofilm bacteria and influenced the interactions and recruitment of additional bacterial communities.}, } @article {pmid34454228, year = {2022}, author = {Kostrytsia, A and Papirio, S and Khodzhaev, M and Morrison, L and Collins, G and Lens, PNL and Ijaz, UZ and Esposito, G}, title = {Biofilm carrier type affects biogenic sulfur-driven denitrification performance and microbial community dynamics in moving-bed biofilm reactors.}, journal = {Chemosphere}, volume = {287}, number = {Pt 1}, pages = {131975}, doi = {10.1016/j.chemosphere.2021.131975}, pmid = {34454228}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Microbiota ; Nitrogen ; Sulfur ; Waste Disposal, Fluid ; Wastewater/analysis ; }, abstract = {Autotrophic denitrification with biosulfur (ADBIOS) provides a sustainable technological solution for biological nitrogen removal from wastewater driven by biogenic S[0], derived from biogas desulfurization. In this study, the effect of different biofilm carriers (conventional AnoxK™ 1 and Z-200 with a pre-defined maximum biofilm thickness) on ADBIOS performance and microbiomics was investigated in duplicate moving bed-biofilm reactors (MBBRs). The MBBRs were operated parallelly in continuous mode for 309 days, whilst gradually decreasing the hydraulic retention time (HRT) from 72 to 21 h, and biosulfur was either pumped in suspension (days 92-223) or supplied in powder form. Highest nitrate removal rates were approximately 225 (±11) mg/L·d and 180 (±7) mg NO3[-]-N/L·d in the MBBRs operated with K1 and Z-200 carriers, respectively. Despite having the same protected surface area for biofilm development in each MBBR, the biomass attached onto the K1 carrier was 4.8-fold more than that on the Z-200 carrier, with part of the biogenic S[0] kept in the biofilm. The microbial communities of K1 and Z-200 biofilms could also be considered similar at cDNA level in terms of abundance (R = 0.953 with p = 0.042). A relatively stable microbial community was formed on K1 carriers, while the active portion of the microbial community varied significantly over time in the MBBRs using Z-200 carriers.}, } @article {pmid34452788, year = {2022}, author = {Panariello, BHD and Cavichioli, EAM and Sochacki, SF and Gandini Junior, LG and Duarte, S}, title = {Effect of blue light plus chlorhexidine therapy on Streptococcus mutans biofilm and its regrowth in an in vitro orthodontic model.}, journal = {American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics}, volume = {161}, number = {1}, pages = {103-114}, doi = {10.1016/j.ajodo.2020.06.050}, pmid = {34452788}, issn = {1097-6752}, mesh = {Animals ; Biofilms ; Cattle ; Chlorhexidine ; *Orthodontic Brackets ; Phototherapy ; *Streptococcus mutans ; }, abstract = {INTRODUCTION: Fixed orthodontic appliances create areas of stagnation for dental biofilms and make it difficult to clean the teeth; therefore, there is a risk of developing incipient caries lesions during the orthodontic treatment. The objective of this study is to determine if the combination of 2 different therapies, phototherapy by blue light (BL) and the antimicrobial 0.12% chlorhexidine (CHX) on enamel, orthodontic brackets, and elastics, would reduce or inhibit mature Streptococcus mutans biofilms and their regrowth on these substrates 24 hours after the application of the treatment; and if this treatment would interfere with bracket adhesion to the enamel.

METHODS: Biofilms of S. mutans UA159 were formed for 5-days over samples composed of a bovine enamel, orthodontic bracket, and orthodontic elastic. Then, the specimens were treated with 0.89% NaCl for 1 minute, BL for 12 minutes (72 J/cm[2]), 0.12% CHX for 1 minute, and BL for 12 minutes, followed by 0.12% CHX for 1 minute (BL+CHX). Biofilm was evaluated by colonies forming units and dry weight immediately after treatments and 24 hours after treatments (regrowth). The pH of the spent media was measured on the fifth and sixth days. Biofilm formation on the samples after the treatments and regrowth was visually evaluated by confocal laser scanning microscopy. Shear bond strength (SBS) between bracket and enamel was evaluated using a universal testing machine at a crosshead speed of 1 mm/min. After bonding, specimens were thermocycled (500× at 5-55°C), treated, and thermocycled again.

RESULTS: After 5 days of biofilm formation, BL+CHX significantly reduced the bacterial viability on enamel compared with NaCl (P = 0.004) and BL (P = 0.014). For bracket and elastic, all the treatments resulted in similar bacterial viability (P ≥0.081). In the regrowth, CHX and BL+CHX significantly reduced the bacterial viability in the enamel compared with the NaCl (P ≤0.015) and BL (P ≤0.013). For bracket, BL+CHX significantly reduced the bacterial viability compared with NaCl (P = 0.008) and BL (P = 0.009). For the elastic, BL+CHX eliminated the biofilms from the substrate. CHX and BL+CHX significantly reduced the bacterial viability 24 hours after treatment for all substrates (P ≤0.05). The media pH significantly increased when samples were treated with CHX and BL+CHX (P ≤0.001). Confocal laser scanning microscopy images visually showed an abundant quantity of red cells in the samples treated with BL+CHX. There was no difference in the SBS between the treatments (P ≥0.932).

CONCLUSIONS: The association between BL and CHX reduced S. mutans biofilm and its regrowth on an in vitro orthodontic model and did not influence the bonding strength between bracket and enamel.}, } @article {pmid34452132, year = {2021}, author = {Allegrone, G and Ceresa, C and Rinaldi, M and Fracchia, L}, title = {Diverse Effects of Natural and Synthetic Surfactants on the Inhibition of Staphylococcus aureus Biofilm.}, journal = {Pharmaceutics}, volume = {13}, number = {8}, pages = {}, pmid = {34452132}, issn = {1999-4923}, support = {FAR project 2019//Università degli Studi del Piemonte Orientale/ ; }, abstract = {A major challenge in the biomedical field is the creation of materials and coating strategies that effectively limit the onset of biofilm-associated infections on medical devices. Biosurfactants are well known and appreciated for their antimicrobial/anti-adhesive/anti-biofilm properties, low toxicity, and biocompatibility. In this study, the rhamnolipid produced by Pseudomonas aeruginosa 89 (R89BS) was characterized by HPLC-MS/MS and its ability to modify cell surface hydrophobicity and membrane permeability as well as its antimicrobial, anti-adhesive, and anti-biofilm activity against Staphylococcus aureus were compared to two commonly used surfactants of synthetic origin: Tween[®] 80 and Triton[TM] X-100. The R89BS crude extract showed a grade of purity of 91.4% and was composed by 70.6% of mono-rhamnolipids and 20.8% of di-rhamnolipids. The biological activities of R89BS towards S. aureus were higher than those of the two synthetic surfactants. In particular, the anti-adhesive and anti-biofilm properties of R89BS and of its purified mono- and di-congeners were similar. R89BS inhibition of S. aureus adhesion and biofilm formation was ~97% and 85%, respectively, and resulted in an increased inhibition of about 33% after 6 h and of about 39% after 72 h when compared to their chemical counterparts. These results suggest a possible applicability of R89BS as a protective coating agent to limit implant colonization.}, } @article {pmid34451969, year = {2021}, author = {Su, FJ and Chen, MM}, title = {Protective Efficacy of Novel Oral Biofilm Vaccines against Lactococcus garvieae Infection in Mullet, Mugil cephalus.}, journal = {Vaccines}, volume = {9}, number = {8}, pages = {}, pmid = {34451969}, issn = {2076-393X}, abstract = {Lactococcus garvieae (L. garvieae) is an important pathogen that causes enormous economic losses in both marine and freshwater aquaculture. At present, antibiotics are the only option for farmers to reduce the losses caused by L. garvieae. However, the usage of antibiotics leads to environmental pollution and the production of drug-resistant strains of bacteria. Therefore, vaccination is preferred as an alternative method to prevent infectious diseases. In this study, we describe an effective approach to the production of an oral biofilm vaccine, using bacteria grown on chitosan particles to form biofilms, and thus providing an inactive pathogen that enhances the immune response in fish. We observed the formation of a biofilm on chitosan particles and administered the novel oral biofilm vaccine to fish. We analyzed the immune responses, including antibody production, phagocytic ability, albumin/globulin ratio and immune-related genes, of vaccinated and control groups of black mullet. Our results show that the phagocytic ability of the biofilm vaccine group was 84%, which is significantly higher than that of the control group, and the antibody production in this group was significantly higher compared with the other group. The mRNA expression levels of immune-related genes (TLR2, IL-1β, TNF-α) were significantly upregulated in the spleen after vaccination. In challenge experiments, the relative percent survival (RPS) was 77% in the biofilm vaccine group, 18% in the whole-cell vaccine group, and 0% in the chitosan particle group at 32 days post-vaccination. In addition, we also found that the relative percent survival (RPS) at 1 day post-vaccination was 74% in the biofilm vaccine group, 42% in the whole-cell vaccine group, and 26% in the chitosan particle group. In both long-term and short-term challenge experiments, the viability of the biofilm vaccine group was significantly higher than that of the whole-cell, chitosan particle and PBS groups. We conclude that based on its protective effect, the L. garvieae biofilm vaccine is better than the whole-cell vaccine when challenged several weeks after vaccination. In addition, the biofilm vaccine also has a greater protective effect than the whole-cell vaccine when challenged immediately after vaccination. Therefore, the biofilm vaccine might represent a novel method for the prevention and treatment of L. garvieae infection.}, } @article {pmid34451434, year = {2021}, author = {Silva, V and Almeida, L and Gaio, V and Cerca, N and Manageiro, V and Caniça, M and Capelo, JL and Igrejas, G and Poeta, P}, title = {Biofilm Formation of Multidrug-Resistant MRSA Strains Isolated from Different Types of Human Infections.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {34451434}, issn = {2076-0817}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main pathogens causing chronic infections, mainly due to its capacity to form biofilms. However, the mechanisms underlying the biofilm formation of MRSA strains from different types of human infections are not fully understood. MRSA strains isolated from distinct human infections were characterized aiming to determine their biofilm-forming capacity, the biofilm resistance to conventional antibiotics and the prevalence of biofilm-related genes, including, icaA, icaB, icaC, icaD, fnbA, fnbB, clfA, clfB, cna, eno, ebpS, fib and bbp. Eighty-three clinical MRSA strains recovered from bacteremia episodes, osteomyelitis and diabetic foot ulcers were used. The biofilm-forming capacity was evaluated by the microtiter biofilm assay and the biofilm structure was analyzed via confocal scanning laser microscopy. The antimicrobial susceptibility of 24-h-old biofilms was assessed against three antibiotics and the biomass reduction was measured. The metabolic activity of biofilms was evaluated by the XTT assay. The presence of biofilm-related genes was investigated by whole-genome sequencing and by PCR. Despite different intensities, all strains showed the capacity to form biofilms. Most strains had also a large number of biofilm-related genes. However, strains isolated from osteomyelitis showed a lower capacity to form biofilms and also a lower prevalence of biofilm-associated genes. There was a significant reduction in the biofilm biomass of some strains tested against antibiotics. Our results provide important information on the biofilm-forming capacity of clinical MRSA strains, which may be essential to understand the influence of different types of infections on biofilm production and chronic infections.}, } @article {pmid34451352, year = {2021}, author = {Burgard, N and Kienitz, M and Jourdan, C and Rüttermann, S}, title = {The Influence of Modified Experimental Dental Resin Composites on the Initial In Situ Biofilm-A Triple-Blinded, Randomized, Controlled Split-Mouth Trial.}, journal = {Polymers}, volume = {13}, number = {16}, pages = {}, pmid = {34451352}, issn = {2073-4360}, support = {RU 825/3-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The purpose of the study was to investigate the bacterial viability of the initial biofilm on the surface of experimental modified dental resin composites. Twenty-five healthy individuals with good oral hygiene were included in this study. In a split-mouth design, they received acrylic splints with five experimental composite resin specimens. Four of them were modified with either a novel polymeric hollow-bead delivery system or methacrylated polymerizable Irgasan (Antibacterial B), while one specimen served as an unmodified control (ST). A delivery system based on Poly-Pore[®] was loaded with one of the active agents: Tego[®] Protect 5000 (Antiadhesive A), Dimethicone (Antiadhesive B), or Irgasan (Antibacterial A). All study subjects refrained from toothbrushing during the study period. Specimens were detached from the splints after 8 h and given a live/dead staining before fluorescence microscopy. A Friedman test and a post hoc Nemenyi test were applied with a significance level at p < 0.05. In summary, all materials but Antibacterial B showed a significant antibacterial effect compared to ST. The results suggested the role of the materials' chemistry in the dominance of cell adhesion. In conclusion, dental resin composites with Poly-Pore-loaded active agents showed antibacterial effectiveness in situ.}, } @article {pmid34450330, year = {2021}, author = {Ruan, X and Deng, X and Tan, M and Wang, Y and Hu, J and Sun, Y and Yu, C and Zhang, M and Jiang, N and Jiang, R}, title = {Effect of resveratrol on the biofilm formation and physiological properties of avian pathogenic Escherichia coli.}, journal = {Journal of proteomics}, volume = {249}, number = {}, pages = {104357}, doi = {10.1016/j.jprot.2021.104357}, pmid = {34450330}, issn = {1876-7737}, mesh = {Animals ; Biofilms ; Chickens ; Escherichia coli ; *Escherichia coli Infections/drug therapy/veterinary ; *Escherichia coli Proteins ; *Poultry Diseases/drug therapy ; Proteomics ; Resveratrol/pharmacology ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is widely distributed, causing great economic losses to the poultry industry. The formation of APEC biofilms causes chronic, persistent, and repeated infections in the clinic, making treatment difficult. Resveratrol is a natural product, which has good health benefits including antimicrobial, anti-inflammatory, and cardiovascular activities. Resveratrol shows efficient inhibition of bacterial biofilm formation. However, a comprehensive understanding of the proteomic properties of APEC treated resveratrol is still lacking. In this study, APEC cells treated by resveratrol were investigated using a label-free differential proteomic method. Several proteins, including those related to a two-component system and chemotaxis, were found to be implicated in APEC biofilm formation. In addition, the physiological properties were significantly changed in terms of purine, pyruvate, and glyoxylate and dicarboxylate metabolism in APEC. Data are available via ProteomeXchange with the identifier PXD025706. We speculated that pyruvate dehydrogenase might be a potential target to inhibit Escherichia coli biofilm formation. Overall, our results indicated that resveratrol inhibits APEC biofilm formation by regulating the levels of proteins in two-component systems, especially chemotaxis proteins. The results showed that resveratrol had a potential application in inhibiting the biofilm formation of APEC. SIGNIFICANCE: This study elucidated the mechanism of resveratrol inhibiting biofilm formation of avian pathogenic Escherichia coli (APEC) based on a label-free differential proteomics. It was indicated that resveratrol inhibits APEC biofilm formation by regulating the levels of proteins in two component systems, especially chemotaxis proteins. Meanwhile, we speculated that pyruvate dehydrogenase might be a potential target to inhibit Escherichia coli biofilm formation. It shows that resveratrol has a potential application prospect in inhibiting the biofilm formation of APEC.}, } @article {pmid34450163, year = {2021}, author = {Qi, J and Gong, M and Zhang, R and Song, Y and Liu, Q and Zhou, H and Wang, J and Mei, Y}, title = {Evaluation of the antibacterial effect of tea tree oil on Enterococcus faecalis and biofilm in vitro.}, journal = {Journal of ethnopharmacology}, volume = {281}, number = {}, pages = {114566}, doi = {10.1016/j.jep.2021.114566}, pmid = {34450163}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Enterococcus faecalis/*drug effects/physiology ; Microbial Sensitivity Tests ; Plant Leaves/chemistry ; Tea Tree Oil/*pharmacology ; }, abstract = {Tea tree essential oil (TTO) is extracted from the leaves of Melaleuca alternifolia by steam distillation. It is well known for its traditional medicinal uses, particularly for the treatment of bruises, insect bites, skin infections, vertigo, convulsions, toothache, and rheumatism. Earlier research has shown that TTO can effectively inhibit oral microorganisms in the root canals. Enterococcus faecalis (E. faecalis) has been considered to be associated with persistent root canal infections and root canal treatment failure. The biofilm of E. faecalis makes it more vigorous, toxic, and resistant to antibiotics.

AIM OF THE STUDY: In this study, our aim was to evaluate the antimicrobial effects of TTO on planktonic E. faecalis and biofilms compared with 0.2% CHX.

MATERIALS AND METHODS: We explored the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), the bacteriostatic rate by MTT assay, the antimicrobial time by time-kill assay, and the effects on cell integrity, the biomass, and bacterial activity of E. faecalis biofilms. Finally, we investigated the microstructure changes of E. faecalis biofilms using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).

RESULTS: The MIC and MBC values were 0.25% and 0.5%, the bacterial inhibition rate, time-kill was dosage dependent, and TTO can effectively destroy membrane integrity. SEM CLSM images revealed that TTO could reduce bacterial aggregation, biofilm thickness and inhibited biofilm formation. The effect of TTO was the same as that of 0.2% CHX at some specific concentrations. In summary, TTO has the potential to be effective against E. faecalis infections.

CONCLUSIONS: TTO was able to inhibit E. faecalis by destroying cell membrane, inhibiting the formation of E. faecalis biofilms, and eliminating mature formed biofilms. In this study, TTO has the potential to be further developed as a novel antibacterial drug.}, } @article {pmid34449059, year = {2021}, author = {Na, SH and Jeon, H and Oh, MH and Kim, YJ and Lee, JC}, title = {Screening of small molecules attenuating biofilm formation of Acinetobacter baumannii by inhibition of ompA promoter activity.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {59}, number = {9}, pages = {871-878}, pmid = {34449059}, issn = {1976-3794}, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/*drug effects/genetics/pathogenicity/physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/*drug effects ; Drug Evaluation, Preclinical ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Promoter Regions, Genetic/*drug effects ; Small Molecule Libraries/*pharmacology ; Virulence/drug effects ; }, abstract = {Anti-virulence therapeutic strategies are promising alternatives against drug-resistant pathogens. Outer membrane protein A (OmpA) plays a versatile role in the pathogenesis and antimicrobial resistance of Acinetobacter baumannii. Therefore, OmpA is an innovative target for anti-virulence therapy against A. baumannii. This study aimed to develop a high-throughput screening (HTS) system to discover small molecules inhibiting the ompA promoter activity of A. baumannii and screen chemical compounds using the bacterial growth-based HTS system. The ompA promoter and open reading frame of nptI fusion plasmids that controlled the expression of nptI encoding resistance to kanamycin by the ompA promoter were constructed and then transformed into A. baumannii ATCC 17978. This reporter strain was applied to screen small molecules inhibiting the ompA promoter activity in a chemical library. Of the 7,520 chemical compounds, 15 exhibited ≥ 70% growth inhibition of the report strain cultured in media containing kanamycin. Three compounds inhibited the expression of ompA and OmpA in the outer membrane of A. baumannii ATCC 17978, which subsequently reduced biofilm formation. In conclusion, our reporter strain is useful for large-scale screening of small molecules inhibiting the ompA expression in A. baumannii. Hit compounds identified by the HTS system are promising scaffolds to develop novel therapeutics against A. baumannii.}, } @article {pmid34448395, year = {2021}, author = {Tran, HA and Tran, PA}, title = {In Situ Coatings of Silver Nanoparticles for Biofilm Treatment in Implant-Retention Surgeries: Antimicrobial Activities in Monoculture and Coculture.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {35}, pages = {41435-41444}, doi = {10.1021/acsami.1c08239}, pmid = {34448395}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Coculture Techniques ; Indoles/chemistry ; Metal Nanoparticles/*chemistry ; Mice ; Microbial Sensitivity Tests ; Osteoblasts/physiology ; Polymers/chemistry ; Proof of Concept Study ; Silver/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/metabolism/physiology ; }, abstract = {Bacterial biofilms are indicated in most medical device-associated infections. Treating these biofilms is challenging yet critically important for applications such as in device-retention surgeries, which can have reinfection rates of up to 80%. This in vitro study centered around our new method of treating biofilm and preventing reinfection. Ionic silver (Ag, in the form of silver nitrate) combined with dopamine and a biofilm-lysing enzyme (α-amylase) were applied to model 4-day-old Staphylococcus aureus biofilms on titanium substrates to degrade the extracellular matrix of the biofilm and kill the biofilm bacteria. In this process, the oxidative self-polymerization of dopamine converted Ag ions into Ag nanoparticles that, together with the resultant self-adhering polydopamine (PDA), formed coatings that strongly bound to the treated substrates. Surprisingly, although these Ag/PDA coatings significantly reduced S. aureus growth in standard bacterial monoculture, they showed much lower antimicrobial activity in coculture of the bacteria and osteoblastic MC3T3-E1 cells in which the bacteria were also found attached to the osteoblasts. This S. aureus- osteoblast interaction was also linked to bacterial survival against gentamicin treatment observed in coculture. Our study thus provided clear evidence suggesting that bacteria's interactions with tissue cells surrounding implants may significantly contribute to their resistance to antimicrobial treatment.}, } @article {pmid34448102, year = {2022}, author = {Teren, M and Shagieva, E and Vondrakova, L and Viktorova, J and Svarcova, V and Demnerova, K and Michova, HT}, title = {Mutagenic strategies against luxS gene affect the early stage of biofilm formation of Campylobacter jejuni.}, journal = {Journal of applied genetics}, volume = {63}, number = {1}, pages = {145-157}, pmid = {34448102}, issn = {2190-3883}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Campylobacter jejuni/genetics ; Carbon-Sulfur Lyases/genetics ; Mutagens ; Quorum Sensing/genetics ; }, abstract = {Currently, it is clear that the luxS gene has an impact on the process of biofilm formation in Campylobacter jejuni. However, even within the species, naturally occurring strains of Campylobacter lacking the luxS gene exist, which can form biofilms. In order to better understand the genetic determinants and the role of quorum sensing through the LuxS/AI-2 pathway in biofilm formation, a set of mutant/complemented strains of C. jejuni 81-176 were prepared. Additionally, the impact of the mutagenic strategy used against the luxS gene was investigated. Biofilm formation was affected by both the presence and absence of the luxS gene, and by the mutagenic strategy used. Analysis by CLSM showed that all mutant strains formed significantly less biofilm mass when compared to the wild-type. Interestingly, the deletion mutant (∆luxS) showed a larger decrease in biofilm mass than the substitution (∙luxS) and insertional inactivated ([Formula: see text]luxS) mutants, even though all the mutant strains lost the ability to produce autoinducer-2 molecules. Moreover, the biofilm of the ∆luxS mutant lacked the characteristic microcolonies observed in all other strains. The complementation of all mutant strains resulted in restored ability to produce AI-2, to form a complex biofilm, and to develop microcolonies at the level of the wild-type.}, } @article {pmid34447490, year = {2021}, author = {Robertsson, C and Svensäter, G and Blum, Z and Jakobsson, ME and Wickström, C}, title = {Proteomic response in Streptococcus gordonii DL1 biofilm cells during attachment to salivary MUC5B.}, journal = {Journal of oral microbiology}, volume = {13}, number = {1}, pages = {1967636}, pmid = {34447490}, issn = {2000-2297}, abstract = {BACKGROUND: Salivary mucin MUC5B seems to promote biodiversity in dental biofilms, and thereby oral health, for example, by inducing synergistic 'mucolytic' activities in a variety of microbial species that need to cooperate for the release of nutrients from the complex glycoprotein. Knowledge of how early colonizers interact with host salivary proteins is integral to better understand the maturation of putatively harmful oral biofilms and could provide key insights into biofilm physiology.

METHODS: The early oral colonizer Streptococcus gordonii DL1 was grown planktonically and in biofilm flow cell systems with uncoated, MUC5B or low-density salivary protein (LDP) coated surfaces. Bacterial cell proteins were extracted and analyzed using a quantitative mass spectrometry-based workflow, and differentially expressed proteins were identified.

RESULTS AND CONCLUSIONS: Overall, the proteomic profiles of S. gordonii DL1 were similar across conditions. Six novel biofilm cell proteins and three planktonic proteins absent in all biofilm cultures were identified. These differences may provide insights into mechanisms for adaptation to biofilm growth in this species. Salivary MUC5B also elicited specific responses in the biofilm cell proteome. These regulations may represent mechanisms by which this mucin could promote colonization of the commensal S. gordonii in oral biofilms.}, } @article {pmid34445806, year = {2021}, author = {Campoccia, D and Montanaro, L and Arciola, CR}, title = {Extracellular DNA (eDNA). A Major Ubiquitous Element of the Bacterial Biofilm Architecture.}, journal = {International journal of molecular sciences}, volume = {22}, number = {16}, pages = {}, pmid = {34445806}, issn = {1422-0067}, support = {Theory-enhancing Project RF-2018-12368273//Ministry of Health for the IRCCS Rizzoli Orthopaedic Institute of Bologna, Italy/ ; }, mesh = {Animals ; Bacteria/*genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; DNA, Bacterial/*genetics ; Extracellular Polymeric Substance Matrix/*genetics ; Humans ; }, abstract = {After the first ancient studies on microbial slime (the name by which the biofilm matrix was initially indicated), multitudes of studies on the morphology, composition and physiology of biofilms have arisen. The emergence of the role that biofilms play in the pathogenesis of recalcitrant and persistent clinical infections, such as periprosthetic orthopedic infections, has reinforced scientific interest. Extracellular DNA (eDNA) is a recently uncovered component that is proving to be almost omnipresent in the extracellular polymeric substance (EPS) of biofilm. This macromolecule is eliciting unprecedented consideration for the critical impact on the pathogenesis of chronic clinical infections. After a systematic review of the literature, an updated description of eDNA in biofilms is presented, with a special focus on the latest findings regarding its fundamental structural role and the contribution it makes to the complex architecture of bacterial biofilms through interactions with a variety of other molecular components of the biofilm matrix.}, } @article {pmid34445798, year = {2021}, author = {Mušković, M and Ćavar, I and Lesar, A and Lončarić, M and Malatesti, N and Gobin, I}, title = {Photodynamic Inactivation of Legionella pneumophila Biofilm Formation by Cationic Tetra- and Tripyridylporphyrins in Waters of Different Hardness.}, journal = {International journal of molecular sciences}, volume = {22}, number = {16}, pages = {}, pmid = {34445798}, issn = {1422-0067}, support = {KK.01.1.1.01.0001//European Regional Development Fund/ ; uniri-biomed-18-171//University of Rijeka/ ; uniri-prirod-18-173//University of Rijeka/ ; }, mesh = {Amoeba/microbiology ; Biofilms/*drug effects ; Cations/*pharmacology ; Hardness/*drug effects ; Legionella pneumophila/*drug effects ; Photosensitizing Agents/*pharmacology ; Porphyrins/*pharmacology ; Singlet Oxygen/pharmacology ; Water/*chemistry ; Water Microbiology ; }, abstract = {The bacterium Legionella pneumophila is still one of the probable causes of waterborne diseases, causing serious respiratory illnesses. In the aquatic systems, L. pneumophila exists inside free-living amoebae or can form biofilms. Currently developed disinfection methods are not sufficient for complete eradication of L. pneumophila biofilms in water systems of interest. Photodynamic inactivation (PDI) is a method that results in an antimicrobial effect by using a combination of light and a photosensitizer (PS). In this work, the effect of PDI in waters of natural origin and of different hardness, as a treatment against L. pneumophila biofilm, was investigated. Three cationic tripyridylporphyrins, which were previously described as efficient agents against L. pneumophila alone, were used as PSs. We studied how differences in water hardness affect the PSs' stability, the production of singlet oxygen, and the PDI activity on L. pneumophila adhesion and biofilm formation and in biofilm destruction. Amphiphilic porphyrin showed a stronger tendency for aggregation in hard and soft water, but its production of singlet oxygen was higher in comparison to tri- and tetracationic hydrophilic porphyrins that were stable in all water samples. All three studied porphyrins were shown to be effective as PDI agents against the adhesion of the L. pneumophila to polystyrene, against biofilm formation, and in the destruction of the formed biofilm, in their micromolar concentrations. However, a higher number of dissolved ions, i.e., water hardness, generally reduced somewhat the PDI activity of all the porphyrins at all tested biofilm growth stages.}, } @article {pmid34445744, year = {2021}, author = {Salvatore, MM and Maione, A and Albarano, L and de Alteriis, E and Carraturo, F and Andolfi, A and Salvatore, F and Galdiero, E and Guida, M}, title = {An Integrated Analysis of Intracellular Metabolites and Virulence Gene Expression during Biofilm Development of a Clinical Isolate of Candida tropicalis on Distinct Surfaces.}, journal = {International journal of molecular sciences}, volume = {22}, number = {16}, pages = {}, pmid = {34445744}, issn = {1422-0067}, mesh = {Biofilms/*growth & development ; Candida tropicalis/genetics/*metabolism/pathogenicity ; Fungal Proteins/genetics/*metabolism ; Humans ; }, abstract = {Emergence of Candida tropicalis, which causes potential life-threatening invasive candidiasis, is often associated with colonization of medical devices as biofilm. Biofilm plays an important role in the virulence of the pathogen because of its complex structure, which provides resistance to conventional antimicrobials. In this study, the metabolic response of a clinical strain of C. tropicalis colonizing three distinct surfaces (polytetrafluoroethylene (PTFE), polystyrene, and polycarbonate) as well as the expression of virulence and stress related genes (ALS3, Hsp21, SAP1, SAP2, SAP3, and CYR1), were explored. Our results showed that lesser biofilm was developed on PTFE compared to polystyrene and polycarbonate. GS-MS metabolic analysis identified a total of 36 metabolites in the intracellular extract of cells grown on polystyrene, polycarbonate, and PTFE, essentially belonging to central carbon metabolism, amino acids, and lipids metabolism. The metabolic analysis showed that saturated and unsaturated fatty acids are preferentially produced during biofilm development on polycarbonate, whereas trehalose and vitamin B6, known as cellular protectors against a variety of stressors, were characteristic of biofilm on PTFE. The results of the transcriptomic analysis consider the different degrees of colonization of the three substrates, being CYR1, which encodes the component of signaling pathway of hyphal formation-cAMP-PKA, downregulated in PTFE biofilm compared to polycarbonate or polystyrene biofilms, while Hsp21 was upregulated in concomitance with the potential unfavorable conditions for biofilm formation on PTFE. Overall, this work provides new insights into the knowledge of C. tropicalis biofilm development on surfaces of medical relevance in the perspective of improving the management of Candida infections.}, } @article {pmid34443617, year = {2021}, author = {Rusakov, A and Kuz'mina, M and Frank-Kamenetskaya, O}, title = {Biofilm Medium Chemistry and Calcium Oxalate Morphogenesis.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {16}, pages = {}, pmid = {34443617}, issn = {1420-3049}, support = {19-17-00141//Russian Science Foundation/ ; }, mesh = {Biofilms/*growth & development ; Calcium Oxalate/*chemistry ; Crystallization ; Hydrogen-Ion Concentration ; }, abstract = {The present study is focused on the effect of biofilm medium chemistry on oxalate crystallization and contributes to the study of the patterns of microbial biomineralization and the development of nature-like technologies, using the metabolism of microscopic fungi. Calcium oxalates (weddellite and whewellite in different ratios) were synthesized by chemical precipitation in a weakly acidic environment (pH = 4-6), as is typical for the stationary phase of micromycetes growth, with a ratio of Ca[2+]/C2O4[2-] = 4.0-5.5, at room temperature. Additives, which are common for biofilms on the surface of stone in an urban environment (citric, malic, succinic and fumaric acids; and K[+], Mg[2+], Fe[3+], Sr[2+], SO4[2+], PO4[3+] and CO3[2+] ions), were added to the solutions. The resulting precipitates were studied via X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). It was revealed that organic acids, excreted by micromicetes, and some environmental ions, as well as their combinations, significantly affect the weddellite/whewellite ratio and the morphology of their phases (including the appearance of tetragonal prism faces of weddellite). The strongest unique effect leading to intensive crystallization of weddellite was only caused by the presence of citric acid additive in the medium. Minor changes in the composition of the additive components can lead to significant changes in the weddellite/whewellite ratio. The effect of the combination of additives on this ratio does not obey the law of additivity. The content of weddellite in the systems containing a representative set of both organic acids and environmental ions is ~20 wt%, which is in good agreement with natural systems.}, } @article {pmid34443457, year = {2021}, author = {Di Salle, A and Viscusi, G and Di Cristo, F and Valentino, A and Gorrasi, G and Lamberti, E and Vittoria, V and Calarco, A and Peluso, G}, title = {Antimicrobial and Antibiofilm Activity of Curcumin-Loaded Electrospun Nanofibers for the Prevention of the Biofilm-Associated Infections.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {16}, pages = {}, pmid = {34443457}, issn = {1420-3049}, support = {PON 03 PE_00110_1/ptd1_000410//Regione Campania/ ; }, mesh = {Anti-Infective Agents/*pharmacology ; *Biofilms/drug effects ; Biphenyl Compounds/chemistry ; Cell Death/drug effects ; Cell Line ; Curcumin/*pharmacology ; Drug Liberation ; Free Radical Scavengers/pharmacology ; Humans ; Infections/*microbiology ; Kinetics ; Microbial Sensitivity Tests ; Nanofibers/*chemistry ; Picrates/chemistry ; Polyesters/chemistry ; Quorum Sensing/drug effects ; Thermogravimetry ; *Tissue Engineering ; }, abstract = {Curcumin extracted from the rhizome of Curcuma Longa has been used in therapeutic preparations for centuries in different parts of the world. However, its bioactivity is limited by chemical instability, water insolubility, low bioavailability, and extensive metabolism. In this study, the coaxial electrospinning technique was used to produce both poly (ε-caprolactone) (PCL)-curcumin and core-shell nanofibers composed of PCL and curcumin in the core and poly (lactic acid) (PLA) in the shell. Morphology and physical properties, as well as the release of curcumin were studied and compared with neat PCL, showing the formation of randomly oriented, defect-free cylindrical fibers with a narrow distribution of the dimensions. The antibacterial and antibiofilm potential, including the capacity to interfere with the quorum-sensing mechanism, was evaluated on Pseudomonas aeruginosa PAO1, and Streptococcus mutans, two opportunistic pathogenic bacteria frequently associated with infections. The reported results demonstrated the ability of the Curcumin-loading membranes to inhibit both PAO1 and S. mutans biofilm growth and activity, thus representing a promising solution for the prevention of biofilm-associated infections. Moreover, the high biocompatibility and the ability to control the oxidative stress of damaged tissue, make the synthesized membranes useful as scaffolds in tissue engineering regeneration, helping to accelerate the healing process.}, } @article {pmid34443349, year = {2021}, author = {Fournière, M and Bedoux, G and Souak, D and Bourgougnon, N and Feuilloley, MGJ and Latire, T}, title = {Effects of Ulva sp. Extracts on the Growth, Biofilm Production, and Virulence of Skin Bacteria Microbiota: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes Strains.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {16}, pages = {}, pmid = {34443349}, issn = {1420-3049}, support = {643 [INR00089]//"Conseil départemental des Côtes d'Armor (CD22)" and "Guingamp Paimpol Agglomération (GPA)"/ ; }, mesh = {Bacteria/*drug effects/*growth & development/pathogenicity ; Dose-Response Relationship, Drug ; Microbiota/*drug effects ; Plant Extracts/*pharmacology ; Propionibacteriaceae/drug effects/growth & development/pathogenicity/physiology ; Skin/*microbiology ; Staphylococcus aureus/drug effects/growth & development/pathogenicity/physiology ; Staphylococcus epidermidis/drug effects/growth & development/pathogenicity/physiology ; Ulva/*chemistry ; Virulence/drug effects ; }, abstract = {Ulva sp. is known to be a source of bioactive compounds such as ulvans, but to date, their biological activity on skin commensal and/or opportunistic pathogen bacteria has not been reported. In this study, the effects of poly- and oligosaccharide fractions produced by enzyme-assisted extraction and depolymerization were investigated, for the first time in vitro, on cutaneous bacteria: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes. At 1000 μg/mL, poly- and oligosaccharide fractions did not affect the growth of the bacteria regarding their generation time. Polysaccharide Ulva sp. fractions at 1000 μg/mL did not alter the bacterial biofilm formation, while oligosaccharide fractions modified S. epidermidis and C. acnes biofilm structures. None of the fractions at 1000 μg/mL significantly modified the cytotoxic potential of S. epidermidis and S. aureus towards keratinocytes. However, poly- and oligosaccharide fractions at 1000 μg/mL induced a decrease in the inflammatory potential of both acneic and non-acneic C. acnes strains on keratinocytes of up to 39.8%; the strongest and most significant effect occurred when the bacteria were grown in the presence of polysaccharide fractions. Our research shows that poly- and oligosaccharide Ulva sp. fractions present notable biological activities on cutaneous bacteria, especially towards C. acnes acneic and non-acneic strains, which supports their potential use for dermo-cosmetic applications.}, } @article {pmid34443301, year = {2021}, author = {Yang, W and Wang, Z and Li, Q and Jia, Y and Song, S and Ma, Z and Liu, J and Wang, J}, title = {Photodynamic Inactivation Using Natural Bioactive Compound Prevents and Disrupts the Biofilm Produced by Staphylococcus saprophyticus.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {16}, pages = {}, pmid = {34443301}, issn = {1420-3049}, mesh = {Biofilms/drug effects/*growth & development ; Biological Products/*pharmacology ; Colony Count, Microbial ; Curcumin/pharmacology ; *Photochemotherapy ; Staphylococcus saprophyticus/cytology/drug effects/*physiology/ultrastructure ; }, abstract = {Staphylococcus saprophyticus, the food-borne bacteria present in dairy products, ready-to-eat food and environmental sources, has been reported with antibiotic resistance, raising concerns about food microbial safety. The antimicrobial resistance of S. saprophyticus requires the development of new strategies. Light- and photosensitizer-based antimicrobial photodynamic inactivation (PDI) is a promising approach to control microbial contamination, whereas there is limited information regarding the effectiveness of PDI on S. saprophyticus biofilm control. In this study, PDI mediated by natural bioactive compound (curcumin) associated with LED was evaluated for its potential to prevent and disrupt S. saprophyticus biofilms. Biofilms were treated with curcumin (50, 100, 200 µM) and LED fluence (4.32 J/cm[2], 8.64 J/cm[2], 17.28 J/cm[2]). Control groups included samples treated only with curcumin or light, and samples received neither curcumin nor light. The action was examined on biofilm mass, viability, cellular metabolic activity and cytoplasmic membrane integrity. PDI using curcumin associated with LED exhibited significant antibiofilm activities, inducing biofilm prevention and removal, metabolic inactivation, intracellular membrane damage and cell death. Likewise, scanning electronic microscopy observations demonstrated obvious structural injury and morphological alteration of S. saprophyticus biofilm after PDI application. In conclusion, curcumin is an effective photosensitizer for the photodynamic control of S. saprophyticus biofilm.}, } @article {pmid34443242, year = {2021}, author = {Ajdnik, U and Luxbacher, T and Vesel, A and Štern, A and Žegura, B and Trček, J and Fras Zemljič, L}, title = {Polysaccharide-Based Bilayer Coatings for Biofilm-Inhibiting Surfaces of Medical Devices.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {16}, pages = {}, pmid = {34443242}, issn = {1996-1944}, support = {J1 9169 and P2-0118//Javna Agencija za Raziskovalno Dejavnost RS/ ; }, abstract = {Chitosan (Chi) and 77KS, a lysine-derived surfactant, form polyelectrolyte complexes that reverse their charge from positive to negative at higher 77KS concentrations, forming aggregates that have been embedded with amoxicillin (AMOX). Dispersion of this complex was used to coat polydimethylsiloxane (PDMS) films, with an additional layer of anionic and hydrophilic hyaluronic acid (HA) as an outer adsorbate layer to enhance protein repulsion in addition to antimicrobial activity by forming a highly hydrated layer in combination with steric hindrance. The formed polysaccharide-based bilayer on PDMS was analyzed by water contact angle measurements, X-ray photoelectron spectroscopy (XPS), and surface zeta (ζ)-potential. All measurements show the existence and adhesion of the two layers on the PDMS surface. Part of this study was devoted to understanding the underlying protein adsorption phenomena and identifying the mechanisms associated with biofouling. Thus, the adsorption of a mixed-protein solution (bovine serum albumin, fibrinogen, γ-globulin) on PDMS surfaces was studied to test the antifouling properties. The adsorption experiments were performed using a quartz crystal microbalance with dissipation monitoring (QCM-D) and showed improved antifouling properties by these polysaccharide-based bilayer coatings compared to a reference or for only one layer, i.e., the complex. This proves the benefit of a second hyaluronic acid layer. Microbiological and biocompatibility tests were also performed on real samples, i.e., silicone discs, showing the perspective of the prepared bilayer coating for medical devices such as prostheses, catheters (balloon angioplasty, intravascular), delivery systems (sheaths, implants), and stents.}, } @article {pmid34443123, year = {2021}, author = {Pavlic, A and Begic, G and Tota, M and Abram, M and Spalj, S and Gobin, I}, title = {Bacterial Exposure to Nickel: Influence on Adhesion and Biofilm Formation on Orthodontic Archwires and Sensitivity to Antimicrobial Agents.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {16}, pages = {}, pmid = {34443123}, issn = {1996-1944}, support = {IP-2020-02-4027//Hrvatska Zaklada za Znanost/ ; IP-2014-09-7500//Hrvatska Zaklada za Znanost/ ; }, abstract = {The presence of nickel could modify bacterial behavior and susceptibility to antimicrobial agents. Adhesion and biofilm formation on orthodontic archwires can be a source of bacterial colonization and possible health hazards. Staphylococcus aureus was subjected to exposure and adaptation to various sub-inhibitory concentrations of nickel. Five strains of bacteria adapted to nickel in concentrations of 62.5-1000 μg/mL were tested for adhesion and biofilm formation on nickel-titanium archwires. Archwires were previously incubated in artificial saliva. Bacteria were incubated with orthodontic wire with stirring for 4 h (adhesion) and 24 h (biofilm formation). The number of adherent bacteria was determined after sonication and cultivation on the Muller-Hinton agar. Disk diffusion method was performed on all bacteria to assess the differences in antimicrobial susceptibility. Bacteria adapted to lower concentrations of nickel adhered better to nickel-titanium than strains adapted to higher concentrations of nickel (p < 0.05). Biofilm formation was highest in strains adapted to 250 and 500 μg/mL of nickel (p < 0.05). The highest biofilm biomass was measured for strains adapted to 250 μg/mL, followed by those adapted to 1000 μg/mL. Bacteria adapted to lower concentrations of nickel demonstrated lower inhibition zone diameters in the disk diffusion method (p < 0.05), indicating increased antimicrobial resistance. In conclusion, bacteria adapted to 250 μg/mL of nickel ions adhered better, demonstrated higher biofilm formation and often had higher antimicrobial resistance than other adapted and non-adapted strains.}, } @article {pmid34442858, year = {2021}, author = {Di Fermo, P and Ciociola, T and Di Lodovico, S and D'Ercole, S and Petrini, M and Giovati, L and Conti, S and Di Giulio, M and Cellini, L}, title = {Antimicrobial Peptide L18R Displays a Modulating Action against Inter-Kingdom Biofilms in the Lubbock Chronic Wound Biofilm Model.}, journal = {Microorganisms}, volume = {9}, number = {8}, pages = {}, pmid = {34442858}, issn = {2076-2607}, support = {Luigina Cellini and Mara Di Giulio FAR 2020//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; Research Grant PRIN 2017 SFBFER from MIUR, Italy.//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; }, abstract = {Chronic wound infections represent an important health problem due to the reduced response to antimicrobial treatment of the pathogens organized in structured biofilms. This study investigated the effects of the previously described antifungal peptide L18R against three representative wound pathogens: Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The antimicrobial activity of L18R was evaluated (i) against single planktonic microbial populations; (ii) on single, dual, and triadic species of biofilms in both the early stage and mature stage; and (iii) in the polymicrobial Lubbock chronic wound biofilm (LCWB) model, mimicking spatial microbial colonization. This study used the evaluation of CFUs, biofilm biomass detection, and confocal and scanning electron microscopy analysis. L18R showed a significant antimicrobial activity against planktonic microorganisms and was able to differentially reduce the biomass of monomicrobial biofilms. No reduction of biomass was observed against the polymicrobial biofilm. In mature LCWB, L18R caused a moderate reduction in total CFU number, with a variable effect on the different microorganisms. Microscopy images confirmed a predominant presence of P.aeruginosa and a lower percentage of C. albicans cells. These findings suggest a modulating action of L18R and recommend further studies on its potential role in chronic wound management in association with conventional antibiotics or alternative treatments.}, } @article {pmid34442788, year = {2021}, author = {Johnson, E and Petersen, T and Goeres, DM}, title = {Characterizing the Shearing Stresses within the CDC Biofilm Reactor Using Computational Fluid Dynamics.}, journal = {Microorganisms}, volume = {9}, number = {8}, pages = {}, pmid = {34442788}, issn = {2076-2607}, support = {NA//BioSurface Technologies Corporation/ ; }, abstract = {Shearing stresses are known to be a critical factor impacting the growth and physiology of biofilms, but the underlying fluid dynamics within biofilm reactors are rarely well characterized and not always considered when a researcher decides which biofilm reactor to use. The CDC biofilm reactor is referenced in validated Standard Test Methods and US EPA guidance documents. The driving fluid dynamics within the CDC biofilm reactor were investigated using computational fluid dynamics. An unsteady, three-dimensional model of the CDC reactor was simulated at a rotation rate of 125 RPM. The reactor showed turbulent structures, with shear stresses averaging near 0.365 ± 0.074 Pa across all 24 coupons. The pressure variation on the coupon surfaces was found to be larger, with a continuous 2-3 Pa amplitude, coinciding with the baffle passage. Computational fluid dynamics was shown to be a powerful tool for defining key fluid dynamic parameters at a high fidelity within the CDC biofilm reactor. The consistency of the shear stresses and pressures and the unsteadiness of the flow within the CDC reactor may help explain its reproducibility in laboratory studies. The computational model will enable researchers to make an informed decision whether the fluid dynamics present in the CDC biofilm reactor are appropriate for their research.}, } @article {pmid34442690, year = {2021}, author = {Jin, F and Yang, H}, title = {Effects of Lactobacillus salivarius LN12 in Combination with Amoxicillin and Clarithromycin on Helicobacter pylori Biofilm In Vitro.}, journal = {Microorganisms}, volume = {9}, number = {8}, pages = {}, pmid = {34442690}, issn = {2076-2607}, support = {HUCXY-2016-010//Shanghai Industry-University Joint Research Program/ ; }, abstract = {Helicobacter pylori is a highly prevalent and harmful gastrointestinal pathogen. Antibiotic resistance and biofilm complexity have led to a decrease in the cure rate. Probiotics are considered to be an adjuvant therapy for clinical Helicobacter pylori infections. However, there is no substantial explanation for the adjuvant role of probiotics on H. pylori biofilm. In this study, the effects of probiotics in combination with amoxicillin (AMX) and clarithromycin (CLR) on H. pylori biofilms were explored in vitro for the first time. The minimum inhibitory concentration (MIC) and the fractional inhibitory concentration (FIC) for H. pylori was determined by the microbroth dilution method, and the plate counting method was used to determine the minimum biofilm removal concentration (MBEC) and survival rate for H. pylori biofilm. The biofilm structure was observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), protein and polysaccharide contents in extracellular polymeric substances (EPS) were determined by the Bradford method and the phenol-sulfate method, respectively. The gene expression levels of cagA and vacA were evaluated by real-time qPCR. Among the ten H. pylori strains, the clinical strain 3192 showed the strongest film-forming ability, the 3192 biofilms significantly improved the resistance to AMX and CLR, and AMX and CLR showed antagonistic effects on planktonic 3192 cells. When the Lactobacillus salivarius LN12 cell-free supernatant (CFS) was in combination with AMX and CLR, the 3192 biofilm structure was destroyed to a greater extent than when separately; more biofilm biomass and protein in EPS was decreased; and the downregulation effect of the virulence gene vacA was also greater than that of single use. In this study, we suggest that the addition of LN12 to AMX and CLR may enhance the therapeutic effect of triple therapy, especially for the treatment of H. pylori biofilms.}, } @article {pmid34442682, year = {2021}, author = {Chamarande, J and Cunat, L and Caillet, C and Mathieu, L and Duval, JFL and Lozniewski, A and Frippiat, JP and Alauzet, C and Cailliez-Grimal, C}, title = {Surface Properties of Parabacteroides distasonis and Impacts of Stress-Induced Molecules on Its Surface Adhesion and Biofilm Formation Capacities.}, journal = {Microorganisms}, volume = {9}, number = {8}, pages = {}, pmid = {34442682}, issn = {2076-2607}, abstract = {The gut microbiota is a complex and dynamic ecosystem whose balance and homeostasis are essential to the host's well-being and whose composition can be critically affected by various factors, including host stress. Parabacteroides distasonis causes well-known beneficial roles for its host, but is negatively impacted by stress. However, the mechanisms explaining its maintenance in the gut have not yet been explored, in particular its capacities to adhere onto (bio)surfaces, form biofilms and the way its physicochemical surface properties are affected by stressing conditions. In this paper, we reported adhesion and biofilm formation capacities of 14 unrelated strains of P. distasonis using a steam-based washing procedure, and the electrokinetic features of its surface. Results evidenced an important inter-strain variability for all experiments including the response to stress hormones. In fact, stress-induced molecules significantly impact P. distasonis adhesion and biofilm formation capacities in 35% and 23% of assays, respectively. This study not only provides basic data on the adhesion and biofilm formation capacities of P. distasonis to abiotic substrates but also paves the way for further research on how stress-molecules could be implicated in P. distasonis maintenance within the gut microbiota, which is a prerequisite for designing efficient solutions to optimize its survival within gut environment.}, } @article {pmid34442645, year = {2021}, author = {Sharma, S and Compant, S and Franken, P and Ruppel, S and Ballhausen, MB}, title = {It Takes Two to Tango: A Bacterial Biofilm Provides Protection against a Fungus-Feeding Bacterial Predator.}, journal = {Microorganisms}, volume = {9}, number = {8}, pages = {}, pmid = {34442645}, issn = {2076-2607}, support = {No. 676480//Horizon 2020 Framework Programme/ ; }, abstract = {Fungus-bacterium interactions are widespread, encompass multiple interaction types from mutualism to parasitism, and have been frequent targets for microbial inoculant development. In this study, using in vitro systems combined with confocal laser scanning microscopy and real-time quantitative PCR, we test whether the nitrogen-fixing bacterium Kosakonia radicincitans can provide protection to the plant-beneficial fungus Serendipita indica, which inhabits the rhizosphere and colonizes plants as an endophyte, from the fungus-feeding bacterium Collimonas fungivorans. We show that K. radicincitans can protect fungal hyphae from bacterial feeding on solid agar medium, with probable mechanisms being quick hyphal colonization and biofilm formation. We furthermore find evidence for different feeding modes of K. radicincitans and C. fungivorans, namely "metabolite" and "hyphal feeding", respectively. Overall, we demonstrate, to our knowledge, the first evidence for a bacterial, biofilm-based protection of fungal hyphae against attack by a fungus-feeding, bacterial predator on solid agar medium. Besides highlighting the importance of tripartite microbial interactions, we discuss implications of our results for the development and application of microbial consortium-based bioprotectants and biostimulants.}, } @article {pmid34442548, year = {2021}, author = {Droumpali, A and Hübner, J and Gram, L and Taboryski, R}, title = {Fabrication of Microstructured Surface Topologies for the Promotion of Marine Bacteria Biofilm.}, journal = {Micromachines}, volume = {12}, number = {8}, pages = {}, pmid = {34442548}, issn = {2072-666X}, abstract = {Several marine bacteria of the Roseobacter group can inhibit other microorganisms and are especially antagonistic when growing in biofilms. This aptitude to naturally compete with other bacteria can reduce the need for antibiotics in large-scale aquaculture units, provided that their culture can be promoted and controlled. Micropatterned surfaces may facilitate and promote the biofilm formation of species from the Roseobacter group, due to the increased contact between the cells and the surface material. Our research goal is to fabricate biofilm-optimal micropatterned surfaces and investigate the relevant length scales for surface topographies that can promote the growth and biofilm formation of the Roseobacter group of bacteria. In a preliminary study, silicon surfaces comprising arrays of pillars and pits with different periodicities, diameters, and depths were produced by UV lithography and deep reactive ion etching (DRIE) on polished silicon wafers. The resulting surface microscale topologies were characterized via optical profilometry and scanning electron microscopy (SEM). Screening of the bacterial biofilm on the patterned surfaces was performed using green fluorescent staining (SYBR green I) and confocal laser scanning microscopy (CLSM). Our results indicate that there is a correlation between the surface morphology and the spatial organization of the bacterial biofilm.}, } @article {pmid34440572, year = {2021}, author = {Guo, L and Yang, L and Qi, Y and Niyazi, G and Zheng, J and Xu, R and Chen, X and Zhang, J and Xi, W and Liu, D and Wang, X and Chen, H and Kong, MG}, title = {Low-Temperature Gas Plasma Combined with Antibiotics for the Reduction of Methicillin-Resistant Staphylococcus aureus Biofilm Both In Vitro and In Vivo.}, journal = {Life (Basel, Switzerland)}, volume = {11}, number = {8}, pages = {}, pmid = {34440572}, issn = {2075-1729}, support = {51977174//National Natural Science Foundation of China/ ; EIPE19310//State Key Laboratory of Electrical Insulation and Power Equipment/ ; 2017M613106//Doctoral Fund of Ministry of Education of China/ ; }, abstract = {Biofilm infections in wounds seriously delay the healing process, and methicillin-resistant Staphylococcus aureus is a major cause of wound infections. In addition to inactivating micro-organisms, low-temperature gas plasma can restore the sensitivity of pathogenic microbes to antibiotics. However, the combined treatment has not been applied to infectious diseases. In this study, low-temperature gas plasma treatment promoted the effects of different antibiotics on the reduction of S. aureus biofilms in vitro. Low-temperature gas plasma combined with rifampicin also effectively reduced the S. aureus cells in biofilms in the murine wound infection model. The blood and histochemical analysis demonstrated the biosafety of the combined treatment. Our findings demonstrated that low-temperature gas plasma combined with antibiotics is a promising therapeutic strategy for wound infections.}, } @article {pmid34440229, year = {2021}, author = {Gheorghe, DC and Ilie, A and Niculescu, AG and Grumezescu, AM}, title = {Preventing Biofilm Formation and Development on Ear, Nose and Throat Medical Devices.}, journal = {Biomedicines}, volume = {9}, number = {8}, pages = {}, pmid = {34440229}, issn = {2227-9059}, abstract = {Otorhinolaryngology is a vast domain that requires the aid of many resources for optimal performance. The medical devices utilized in this branch share common problems, such as the formation of biofilms. These structured communities of microbes encased in a 3D matrix can develop antimicrobial resistance (AMR), thus making it a problem with challenging solutions. Therefore, it is of concern the introduction in the medical practice involving biomaterials for ear, nose and throat (ENT) devices, such as implants for the trachea (stents), ear (cochlear implants), and voice recovery (voice prosthetics). The surface of these materials must be biocompatible and limit the development of biofilm while still promoting regeneration. In this respect, several surface modification techniques and functionalization procedures can be utilized to facilitate the success of the implants and ensure a long time of use. On this note, this review provides information on the intricate underlying mechanisms of biofilm formation, the large specter of implants and prosthetics that are susceptible to microbial colonization and subsequently related infections. Specifically, the discussion is particularized on biofilm development on ENT devices, ways to reduce it, and recent approaches that have emerged in this field.}, } @article {pmid34439861, year = {2021}, author = {Mayer, M and Matiuhin, Y and Nawatha, M and Tabachnikov, O and Fish, I and Schutz, N and Dvir, H and Landau, M}, title = {Structural and Functional Insights into the Biofilm-Associated BceF Tyrosine Kinase Domain from Burkholderia cepacia.}, journal = {Biomolecules}, volume = {11}, number = {8}, pages = {}, pmid = {34439861}, issn = {2218-273X}, mesh = {Bacterial Proteins/*chemistry/*physiology ; Biofilms/*growth & development ; Burkholderia cepacia/*physiology ; Crystallography, X-Ray/methods ; Humans ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein-Tyrosine Kinases/*chemistry/*physiology ; Virulence/physiology ; }, abstract = {BceF is a bacterial tyrosine kinase (BY-kinase) from Burkholderia cepacia, a Gram-negative bacterium accountable for respiratory infections in immunocompromised and cystic fibrosis patients. BceF is involved in the production of exopolysaccharides secreted to the biofilm matrix and promotes resistant and aggressive infections. BY-kinases share no homology with mammalian kinases, and thereby offer a means to develop novel and specific antivirulence drugs. Here, we report the crystal structure of the BceF kinase domain at 1.85 Å resolution. The isolated BceF kinase domain is assembled as a dimer in solution and crystallized as a dimer in the asymmetric unit with endogenous adenosine-diphosphate bound at the active sites. The low enzymatic efficiency measured in solution may be explained by the partial obstruction of the active sites at the crystallographic dimer interface. This study provides insights into self-assembly and the specific activity of isolated catalytic domains. Several unique variations around the active site compared to other BY-kinases may allow for structure-based design of specific inhibitors to target Burkholderia cepacia virulence.}, } @article {pmid34439058, year = {2021}, author = {Grilo, ML and Pereira, A and Sousa-Santos, C and Robalo, JI and Oliveira, M}, title = {Climatic Alterations Influence Bacterial Growth, Biofilm Production and Antimicrobial Resistance Profiles in Aeromonas spp.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {34439058}, issn = {2079-6382}, support = {UIDB/00276/2020; MARE/UIDB/MAR/04292/2020; MARE/UIDP/MAR/04292/2020//Fundação para a Ciência e a Tecnologia/ ; C10571K//Universidade de Lisboa/ ; }, abstract = {Climate change is expected to create environmental disruptions that will impact a wide array of biota. Projections for freshwater ecosystems include severe alterations with gradients across geographical areas. Life traits in bacteria are modulated by environmental parameters, but there is still uncertainty regarding bacterial responses to changes caused by climatic alterations. In this study, we used a river water microcosm model to evaluate how Aeromonas spp., an important pathogenic and zoonotic genus ubiquitary in aquatic ecosystems, responds to environmental variations of temperature and pH as expected by future projections. Namely, we evaluated bacterial growth, biofilm production and antimicrobial resistance profiles of Aeromonas species in pure and mixed cultures. Biofilm production was significantly influenced by temperature and culture, while temperature and pH affected bacterial growth. Reversion of antimicrobial susceptibility status occurred in the majority of strains and tested antimicrobial compounds, with several combinations of temperature and pH contributing to this effect. Current results highlight the consequences that bacterial genus such as Aeromonas will experience with climatic alterations, specifically how their proliferation and virulence and phenotypic resistance expression will be modulated. Such information is fundamental to predict and prevent future outbreaks and deleterious effects that these bacterial species might have in human and animal populations.}, } @article {pmid34439027, year = {2021}, author = {Naksagoon, T and Takenaka, S and Nagata, R and Sotozono, M and Ohsumi, T and Ida, T and Edanami, N and Maeda, T and Noiri, Y}, title = {A Repeated State of Acidification Enhances the Anticariogenic Biofilm Activity of Glass Ionomer Cement Containing Fluoro-Zinc-Silicate Fillers.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {34439027}, issn = {2079-6382}, support = {30320//Mitsubishi Foundation/ ; }, abstract = {This study aimed to evaluate the anticariogenic biofilm activity of a novel zinc-containing glass ionomer cement, Caredyne Restore (CR), using a flow-cell system that reproduces Stephan responses. Streptococcus mutans biofilms were cultured on either CR or hydroxyapatite (HA) discs mounted on a modified Robbins device. The media were allowed to flow at a speed of 2 mL/min for 24 h while exposed to an acidic buffer twice for 30 min to mimic dietary uptake. Acid exposure enhanced biofilm inhibition in the CR group, which showed 2.6 log CFU/mm[2] in viable cells and a 2 log copies/mL reduction in total cells compared to the untreated group after 24 h of incubation, suggesting enhanced anticariogenic activity due to the release of fluoride and zinc ions. However, there was no difference in the number of viable and total cells between the two experimental groups after 24 h of incubation in the absence of an acidic environment. The anticariogenic biofilm activity of CR occurs in acidic oral environments, for example in the transient pH drop following dietary uptake. CR restorations are recommended in patients at high risk of caries due to hyposalivation, difficulty brushing, and frequent sugar intake.}, } @article {pmid34438991, year = {2021}, author = {Nowak, M and Barańska-Rybak, W}, title = {Nanomaterials as a Successor of Antibiotics in Antibiotic-Resistant, Biofilm Infected Wounds?.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {34438991}, issn = {2079-6382}, abstract = {Chronic wounds are a growing problem for both society and patients. They generate huge costs for treatment and reduce the quality of life of patients. The greatest challenge when treating a chronic wound is prolonged infection, which is commonly caused by biofilm. Biofilm makes bacteria resistant to individuals' immune systems and conventional treatment. As a result, new treatment options, including nanomaterials, are being tested and implemented. Nanomaterials are particles with at least one dimension between 1 and 100 nM. Lipids, liposomes, cellulose, silica and metal can be carriers of nanomaterials. This review's aim is to describe in detail the mode of action of those molecules that have been proven to have antimicrobial effects on biofilm and therefore help to eradicate bacteria from chronic wounds. Nanoparticles seem to be a promising treatment option for infection management, which is essential for the final stage of wound healing, which is complete wound closure.}, } @article {pmid34438947, year = {2021}, author = {Barber, KE and Shammout, Z and Smith, JR and Kebriaei, R and Morrisette, T and Rybak, MJ}, title = {Biofilm Time-Kill Curves to Assess the Bactericidal Activity of Daptomycin Combinations against Biofilm-Producing Vancomycin-Resistant Enterococcus faecium and faecalis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {34438947}, issn = {2079-6382}, abstract = {INTRODUCTION: E. faecium and E. faecalis are responsible for 13.9% of hospital-acquired infections with frequent resistance to vancomycin (82.6% of E. faecium, 9.5% of E. faecalis). Medical device infections secondary to enterococci often require combination therapy due to impaired activity against biofilm embedded cells. In vitro data demonstrate synergistic activity of daptomycin combinations. Using a novel, biofilm time-kill approach, we evaluated whether daptomycin combinations maintained synergy against biofilm-producing E. faecium and E. faecalis.

METHODS: Broth microdilution (BMD) and biofilm MIC (bMIC) values for daptomycin, ampicillin, ceftriaxone, fosfomycin, and rifampin were determined against biofilm-producing E. faecium and E. faecalis. Daptomycin combination bMIC values were determined in the presence of biologic concentrations of other antimicrobials. Synergy was evaluated against two E. faecalis (R6981, R7808) and two E. faecium (5938 and 8019) using a previously described biofilm time-kill method. Synergy was defined as ≥2 log10 CFU/cm[2] reduction over the most active agent alone. Bactericidal activity was defined as ≥3 log10 CFU/cm[2] reduction.

RESULTS: Daptomycin bMICs were 2-8-fold higher than BMD. In the presence of other antimicrobials, daptomycin bMICs were reduced ≥ two-fold in dilutions. Ceftriaxone and ampicillin demonstrated the most potent combinations with daptomycin, yielding synergy against three of four strains. Daptomycin plus rifampin was synergistic against E. faecium 5938 and E. faecalis 6981 and produced bactericidal kill. The combination of daptomycin plus fosfomycin displayed synergy solely against E. faecalis 6981.

CONCLUSIONS: Daptomycin combinations with beta-lactams demonstrated promising synergistic activity against both E. faecium and E. faecalis. While daptomycin plus rifampin yielded bactericidal results, the effect was not seen across all organisms. These combinations warrant further evaluation to determine the optimal dose and response.}, } @article {pmid34438488, year = {2021}, author = {Elumalai, P and Parthipan, P and AlSalhi, MS and Huang, M and Devanesan, S and Karthikeyan, OP and Kim, W and Rajasekar, A}, title = {Characterization of crude oil degrading bacterial communities and their impact on biofilm formation.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {286}, number = {}, pages = {117556}, doi = {10.1016/j.envpol.2021.117556}, pmid = {34438488}, issn = {1873-6424}, mesh = {Bacteria/genetics ; Biodegradation, Environmental ; Biofilms ; Corrosion ; *Petroleum ; }, abstract = {In the present study, produced water sample collected from the Indian crude oil reservoir is used to enrich the bacterial communities. The impact of these enriched bacterial communities on the biodegradation of crude oil, biofilm formation, and biocorrosion process are elucidated. A crude oil degradation study is carried out with the minimal salt medium and 94% of crude oil was utilized by enriched bacterial communities. During the crude oil degradation many enzymes including alkane hydroxylase, alcohol dehydrogenase, and lipase are playing a key role in the biodegradation processes. The role of enriched bacterial biofilm on biocorrosion reactions are monitored by weight loss studies and electrochemical analysis. Weight loss study revealed that the biotic system has vigorous corrosion attacks compared to the abiotic system. Both AC-Impedance and Tafel analysis confirmed that the nature of the corrosion reaction take place in the biotic system. Very less charge transfer resistance and higher corrosion current are observed in the biotic system than in the abiotic system. Scanning electron microscope confirms that the dense biofilm formation favoured the pitting type of corrosion. X-ray diffraction analysis confirms that the metal oxides formed in the corrosion systems (biotic). From the metagenomic analysis of the V3-V4 region revealed that presence of diverse bacterial communities in the biofilm, and most of them are uncultured/unknown. Among the known genus, Bacillus, Halomonas, etc are dominant in the enriched bacterial biofilm sample. From this study, we conclude that the uncultured bacterial strains are found to be playing a key role in the pitting type of corrosion and they can utilize crude oil hydrocarbons, which make them succeeded in extreme oil reservoir environments.}, } @article {pmid34436122, year = {2021}, author = {Lara-Juache, HR and Ávila-Hernández, JG and Rodríguez-Durán, LV and Michel, MR and Wong-Paz, JE and Muñiz-Márquez, DB and Veana, F and Aguilar-Zárate, M and Ascacio-Valdés, JA and Aguilar-Zárate, P}, title = {Characterization of a Biofilm Bioreactor Designed for the Single-Step Production of Aerial Conidia and Oosporein by Beauveria bassiana PQ2.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {8}, pages = {}, pmid = {34436122}, issn = {2309-608X}, support = {IT17A895//Tecnológico Nacional de México/ ; }, abstract = {Beauveria bassiana is an entomopathogenic fungus that is used for the biological control of different agricultural pest insects. B. bassiana is traditionally cultivated in submerged fermentation and solid-state fermentation systems to obtain secondary metabolites with antifungal activity and infective spores. This work presents the design and characterization of a new laboratory-scale biofilm bioreactor for the simultaneous production of oosporein and aerial conidia by B. bassiana PQ2. The reactor was built with materials available in a conventional laboratory. KLa was determined at different air flows (1.5-2.5 L/min) by two different methods in the liquid phase and in the exhaust gases. The obtained values showed that an air flow of 2.5 L/min is sufficient to ensure adequate aeration to produce aerial conidia and secondary metabolites by B. bassiana. Under the conditions studied, a concentration of 183 mg oosporein per liter and 1.24 × 10[9] spores per gram of support was obtained at 168 h of culture. These results indicate that the biofilm bioreactor represents a viable alternative for the production of products for biological control from B. bassiana.}, } @article {pmid34435995, year = {2021}, author = {Maktabi, H and Ibrahim, MS and Balhaddad, AA and Alkhubaizi, Q and Garcia, IM and Collares, FM and Strassler, H and Fugolin, APP and Pfeifer, CS and Melo, MAS}, title = {Improper Light Curing of Bulkfill Composite Drives Surface Changes and Increases S. mutans Biofilm Growth as a Pathway for Higher Risk of Recurrent Caries around Restorations.}, journal = {Dentistry journal}, volume = {9}, number = {8}, pages = {}, pmid = {34435995}, issn = {2304-6767}, abstract = {How dentists cure a resin-based material has deleterious effects on the material's properties and its interaction with surrounding dental tissues. Biofilm accumulation has been implicated in the pathogenesis of carious lesions around dental restorations, with its composition manifesting expressed dysbiosis in patients suffering from dental caries. To evaluate the influence of varying radiant exposure on the degree of conversion (DC%), Streptococcus mutans biofilm growth, and surface roughness of bulk-fill composites under different light-curing conditions. Two light-curing units (LCU) at 600 and 1000 mW/cm[2] were used to simulate curing conditions with different angulations (∢20° and ∢35°) or 2 mm-distance displacements of the LCU tip. The radiant exposure (RE) was assessed, and the composites were analyzed for DC%. Biofilm formation was induced over the bulk-fill composites and analyzed via colony-forming units counting and scanning electron microscopy (SEM). The surface roughness was analyzed via a profilometer and SEM after biofilm formation. Curing conditions with different angulation or displacement decreased RE compared to the "optimal condition". The moderately (∢35°) angulated LCU tip and low (600 mW/cm[2]) radiant emittance significantly reduced the DC% (p < 0.05). The difference in DC% between the top and bottom of the composites ranged from 8 to 11% for 600 mW/cm[2] and 10 to 20% for 1000 mW/cm[2]. Greater S. mutans biofilm and surface changes were found in composites with non-optimal RE delivery (e.g., tip displacement and angulation) (p < 0.05). Inadequate polymerization of bulk-fill composites was associated with more biofilm accumulation and surface topography changes. Overall, non-optimally performed curing procedures reduced the amount of delivered RE, which led to low DC%, more biofilm formation, and higher surface roughness. The improper light-curing of bulk-fill composites compromises their physicochemical and biological properties, which could lead to inferior clinical performance and reduced restorative treatments' longevity.}, } @article {pmid34435871, year = {2021}, author = {Alio, I and Gudzuhn, M and Pérez García, P and Danso, D and Schoelmerich, MC and Mamat, U and Schaible, UE and Steinmann, J and Yero, D and Gibert, I and Kohl, TA and Niemann, S and Gröschel, MI and Haerdter, J and Hackl, T and Vollstedt, C and Bömeke, M and Egelkamp, R and Daniel, R and Poehlein, A and Streit, WR}, title = {Erratum for Alio et al., "Phenotypic and Transcriptomic Analyses of Seven Clinical Stenotrophomonas maltophilia Isolates Identify a Small Set of Shared and Commonly Regulated Genes Involved in the Biofilm Lifestyle".}, journal = {Applied and environmental microbiology}, volume = {87}, number = {18}, pages = {e0130421}, doi = {10.1128/AEM.01304-21}, pmid = {34435871}, issn = {1098-5336}, } @article {pmid34435393, year = {2021}, author = {Jensen, PØ and Rumbaugh, K}, title = {Misleading mental models: Ceci n'est pas un biofilm.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {129}, number = {10}, pages = {577-578}, doi = {10.1111/apm.13172}, pmid = {34435393}, issn = {1600-0463}, mesh = {*Biofilms ; Humans ; }, } @article {pmid34432212, year = {2022}, author = {Gogoi, M and Mukherjee, I and Ray Chaudhuri, S}, title = {Characterization of ammonia remover Bacillus albus (ASSF01) in terms of biofilm-forming ability with application in aquaculture effluent treatment.}, journal = {Environmental science and pollution research international}, volume = {29}, number = {41}, pages = {61838-61855}, pmid = {34432212}, issn = {1614-7499}, support = {UGC-DAE-CSR-KC/CRS/19/TE07/1069/1085//UGC-DAE Consortium for Scientific Research, University Grants Commission/ ; UGC-DAE-CSR-KC/CRS/15/IOP/01/0626//UGC-DAE Consortium for Scientific Research, University Grants Commission/ ; F. No. 5-1/2014-T.S.VII dt 7th Aug 2014//Ministry of Human Resource Development/ ; BIRAC/KIIT0200/BIG-10/17//Biotechnology Industry Research Assistance Council/ ; }, mesh = {*Ammonia/analysis ; Aquaculture ; Bacillus ; Biofilms ; Bioreactors/microbiology ; Nitrogen/analysis ; Waste Disposal, Fluid/methods ; *Wastewater/analysis ; }, abstract = {Presence of higher concentration of ammonia (> 0.5 mg/L) as well as nitrite (> 0.2 mg/L) in aquaculture environment create difficulties for fish survival. The existing methods for removal of these pollutants are time-consuming. A stable biofilm-based system for ammonia removal from aquaculture wastewater was developed in the current study to overcome the limitations of conventional treatment processes. In order to do so, initially the bacterial candidate was well characterized and tested for rapid biofilm development. The ammonia bioremediating Bacillus albus (ASSF01), from the activated sludge of shrimp farm, with a generation time of 67 min 12 s in suspension culture, was a structured biofilm former. The staining based measurement showed biofilm initiation from the very first hour of incubation. This finding was further validated using scanning electron microscopy (SEM), profilometry, and ellipsometry with Brewster angular microscopy (BAM). Hurst exponent (H) calculation using the profilometer and ellipsometer data yielded a value of H of above 0.9 and 0.62, indicating positive correlation or persistence behavior, hence a stable biofilm former. Each method of biofilm measurement, in spite of variation in complexity and sensitivity, was equally effective for biofilm progression analysis. The generation time of ASSF01 upon immobilization was 15 min and 36 s, ensuring rapid development of stable system. Response surface methodology (RSM)-based optimization of aquaculture wastewater treatment by the isolate in a biofilm reactor at ambient temperature revealed the optimum influent concentration of ammonia (3.2 mg/L), nitrate (6.89 mg/L), and phosphate (1.17 mg/L) to be reduced to discharge level (as per aquaculture requirement) with 14 h of hydraulic retention time. This study demonstrates the potential of the isolate as an efficient bioremediant for treating ammonia-containing aquaculture wastewater in a single unit biofilm reactor, ensuring rapid stabilization, environmental protection, and aquaculture sustenance.}, } @article {pmid34431209, year = {2021}, author = {Pan, L and Gardner, CL and Beliakoff, R and da Silva, D and Zuo, R and Pagliai, FA and Padgett-Pagliai, KA and Merli, ML and Bahadiroglu, E and Gonzalez, CF and Lorca, GL}, title = {PrbP modulates biofilm formation in Liberibacter crescens.}, journal = {Environmental microbiology}, volume = {23}, number = {11}, pages = {7121-7138}, doi = {10.1111/1462-2920.15740}, pmid = {34431209}, issn = {1462-2920}, mesh = {Biofilms ; *Citrus/microbiology ; Liberibacter ; Plant Diseases/microbiology ; *Rhizobiaceae/genetics ; }, abstract = {In Liberibacter asiaticus, PrbP is a transcriptional regulatory protein involved in survival and persistence during host infection. Tolfenamic acid was previously found to inhibit interactions between PrbP and the promotor region of rplK, resulting in reduced survival of L. asiaticus in the citrus host. In this study, we performed transcriptome analyses to elucidate the PrbP regulon in L. crescens, as it is phylogenetically the closest related species to L. asiaticus that can be grown in laboratory conditions. Chemical inhibition of PrbP with tolfenamic acid revealed that PrbP is involved in the regulation of diverse cellular processes, including stress response, cell motility, cell cycle and biofilm formation. In vitro DNA binding and bacterial two-hybrid assays also suggested that PrbP is a global regulator of multiple transcription factors (RpoH, VisN, PleD, MucR, MocR and CtrA) at both transcriptional and/or post-transcriptional levels. Sub-lethal concentrations of tolfenamic acid significantly reduced the attachment of L. crescens during biofilm formation and decreased long-term persistence in biofilm structures. Overall, our findings show the importance of PrbP in regulating diverse biological processes through direct and indirect interactions with other transcriptional regulators in L. crescens.}, } @article {pmid34429815, year = {2021}, author = {Singh, S and Tan, CL and Ahmad, AR}, title = {Explaining Osteomyelitis and Prosthetic Joint Infections (PJI) in terms of Biofilm - A Review.}, journal = {Malaysian orthopaedic journal}, volume = {15}, number = {2}, pages = {1-8}, pmid = {34429815}, issn = {1985-2533}, abstract = {Osteomyelitis is a chronic infection of bones. Eradication of bone infection is usually with antibiotics and debridement, but it is slow and the infection can recur even after many years. It is now established that osteomyelitis is due to biofilm and a better understanding of the process is required. We review the development of biofilm and apply it to osteomyelitis management. The planktonic microbes' response to adverse conditions is the formation of biofilm. Bacterial infections in planktonic forms cause infections that can be controlled with antibiotics and immunisation, however the same microbe when its phenotype becomes biofilm is more resilient. The understanding of how planktonic bacteria convert to biofilm is one of the aims set out for this article.}, } @article {pmid34428505, year = {2021}, author = {Yui, S and Karia, K and Ali, S and Muzslay, M and Wilson, P}, title = {Thermal disinfection at suboptimal temperature of Pseudomonas aeruginosa biofilm on copper pipe and shower hose materials.}, journal = {The Journal of hospital infection}, volume = {117}, number = {}, pages = {103-110}, doi = {10.1016/j.jhin.2021.08.016}, pmid = {34428505}, issn = {1532-2939}, mesh = {Biofilms ; *Copper/pharmacology ; Disinfection ; Humans ; *Pseudomonas aeruginosa ; Temperature ; }, abstract = {BACKGROUND: Hospital-acquired infections caused by Pseudomonas aeruginosa have been linked to contaminated shower systems in health care. Thermal disinfection, whereby colonized outlets are flushed with existing hot water supplies, is a commonly used method to disinfect contaminated systems. Temperatures of 60°C are recommended for inactivation of P. aeruginosa; however, this is often not achievable at outlets.

AIM: To investigate whether thermal disinfection at a suboptimal temperature (58°C) can effectively eradicate planktonic P. aeruginosa and biofilm adherent on copper piping and shower hoses. Exposure times of up to 60 min and efficacy of repeated cycles were evaluated.

METHODS: A type culture and an environmental strain of P. aeruginosa isolated from a hospital shower were tested. Planktonic bacteria and biofilm adhered to sections of copper pipe and shower hoses were exposed to water at 58°C for up to 60 min. Biofilms were tested with static water, flushing water and repeated cycles of disinfection. Remaining viable bacteria after disinfection were enumerated.

FINDINGS: Planktonic P. aeruginosa remained viable after up to 60 min of thermal disinfection. With static water, biofilm was removed from copper piping after 15 min, but remained viable in shower hoses for up to 60 min. With thermal flushing, biofilm was fully eradicated from copper piping after 2 min, but remained viable on shower hoses. Repeated cycles did not shorten thermal disinfection exposure times.

CONCLUSION: Thermal disinfection at 58°C was effective at eliminating biofilm on copper; however, biofilm on shower hoses remained viable after 60 min of exposure.}, } @article {pmid34428502, year = {2021}, author = {Naziri, Z and Kilegolan, JA and Moezzi, MS and Derakhshandeh, A}, title = {Biofilm formation by uropathogenic Escherichia coli: a complicating factor for treatment and recurrence of urinary tract infections.}, journal = {The Journal of hospital infection}, volume = {117}, number = {}, pages = {9-16}, doi = {10.1016/j.jhin.2021.08.017}, pmid = {34428502}, issn = {1532-2939}, mesh = {Biofilms ; *Escherichia coli Infections ; Humans ; *Urinary Tract Infections ; *Uropathogenic Escherichia coli/genetics ; Virulence Factors ; }, abstract = {BACKGROUND: Uropathogenic Escherichia coli (UPEC) are the principal cause of urinary tract infections (UTIs) which can be either hospital- or community-acquired. The most crucial factor in the persistence and recurrence of UTIs is the biofilm formation ability of UPEC, which protects them against antimicrobial treatment.

AIM: To investigate the genetic relatedness, biofilm formation ability, and biofilm-related genes in UPEC isolated from hospital- and community-acquired UTI patients.

METHODS: In vitro biofilm formation ability of 100 UPEC isolates, collected from the urine samples of 49 inpatients and 51 outpatients with UTIs, was assessed by the microtitre plate method. The association between the presence of fimH, papC, sfa/focDE, csgA, crl, afa, flu, and bcsA genes and biofilm formation ability of UPEC was statistically analysed. The genetic relatedness of UPEC isolates was evaluated by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR).

FINDINGS: Overall, 99% of the UPEC isolates showed in vitro biofilm formation ability, and 27% of the isolates were moderate to strong biofilm producers. Only the presence of sfa/focDE gene was significantly associated with moderate and strong biofilm formation by the UPEC isolates. Analysis of dendrograms revealed higher genetic similarities among UPEC isolates of inpatients compared with outpatients.

CONCLUSION: Based on the results, selection of effective therapeutic approaches, which can affect both biofilm formation and enclosed UPEC, is important for preventing recurrent UTIs. The common UPEC clones among inpatients in different hospital units emphasize the need for more rigid control measures to prevent the spread of UPEC in hospitalized patients and to reduce the occurrence of hospital-acquired UTIs.}, } @article {pmid34427509, year = {2021}, author = {Gong, T and He, X and Chen, J and Tang, B and Zheng, T and Jing, M and Lin, Y and Pan, Y and Ma, Q and Li, Y and Zhou, X}, title = {Transcriptional Profiling Reveals the Importance of RcrR in the Regulation of Multiple Sugar Transportation and Biofilm Formation in Streptococcus mutans.}, journal = {mSystems}, volume = {6}, number = {4}, pages = {e0078821}, pmid = {34427509}, issn = {2379-5077}, support = {81670978//National Natural Science Foundation of China (NSFC)/ ; 31870065//National Natural Science Foundation of China (NSFC)/ ; }, abstract = {The ability of Streptococcus mutans to survive and cause dental caries is dependent on its ability to metabolize various carbohydrates, accompanied by extracellular polysaccharide synthesis and biofilm formation. Here, the role of an rel competence-related regulator (RcrR) in the regulation of multiple sugar transportation and biofilm formation is reported. The deletion of the rcrR gene in S. mutans caused delayed growth, decreased biofilm formation ability, and affected the expression level of its multiple sugar transportation-related genes. Transcriptional profiling revealed 17 differentially expressed genes in the rcrR mutant. Five were downregulated and clustered with the sugar phosphotransferase (PTS) systems (mannitol- and trehalose-specific PTS systems). The conserved sites bound by the rcrR promoter were then determined by electrophoretic mobility shift assays (EMSAs) and DNase I footprinting assays. Furthermore, a potential binding motif in the promoters of the two PTS operons was predicted using MEME Suite 5.1.1. RcrR could bind to the promoter regions of the two operons in vitro, and the sugar transporter-related genes of the two operons were upregulated in an rcrR-overexpressing strain. In addition, when RcrR-binding sites were deleted, the growth rates and final yield of S. mutans were significantly decreased in tryptone-vitamin (TV) medium supplemented with different sugars, but not in absolute TV medium. These results revealed that RcrR acted as a transcription activator to regulate the two PTS systems, accompanied by multiple sugar transportation and biofilm formation. Collectively, these results indicate that RcrR is a critical transcription factor in S. mutans that regulates bacterial growth, biofilm formation, and multiple sugar transportation. IMPORTANCE The human oral cavity is a constantly changing environment. Tooth decay is a commonly prevalent chronic disease mainly caused by the cariogenic bacterium Streptococcus mutans. S. mutans is an oral pathogen that metabolizes various carbohydrates into extracellular polysaccharides (EPSs), biofilm, and tooth-destroying lactic acid. The host diet strongly influences the availability of multiple carbohydrates. Here, we showed that the RcrR transcription regulator plays a significant role in the regulation of biofilm formation and multiple sugar transportation. Further systematic evaluation of how RcrR regulates the transportation of various sugars and biofilm formation was also conducted. Notably, this study decrypts the physiological functions of RcrR as a potential target for the better prevention of dental caries.}, } @article {pmid34426740, year = {2021}, author = {Folliero, V and Franci, G and Dell'Annunziata, F and Giugliano, R and Foglia, F and Sperlongano, R and De Filippis, A and Finamore, E and Galdiero, M}, title = {Evaluation of Antibiotic Resistance and Biofilm Production among Clinical Strain Isolated from Medical Devices.}, journal = {International journal of microbiology}, volume = {2021}, number = {}, pages = {9033278}, pmid = {34426740}, issn = {1687-918X}, abstract = {Microbial biofilms pose a serious threat to patients requiring medical devices (MDs). Prolonged periods of implantation carry a high risk of device-related infections (DRIs). Patients with DRIs often have negative outcomes following the failure of antibiotic treatment. Resistant DRIs are mainly due to the MDs contamination by bacteria producing biofilm. The present study aimed to detect biofilm formation among MD bacterial isolates and to explore their antibiotic resistance profile. The study was conducted on 76 MDs, collected at University Hospital of Campania "Luigi Vanvitelli," between October 2019 and September 2020. Identification of isolates and antibiotic susceptibility testing were performed using Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and Phoenix Becton Dickinson, respectively. Biofilm-forming abilities were assessed using the tissue culture plate (TCP) method. Among the 94 MDs isolated strains, 42.7% were Gram-positive, 40.3% Gram-negative, and 17% Candida species. Among 78 bacterial strains, 43.6% were non-biofilm producers while 56.4% produced biofilms. All biofilm producing isolates were sensitive to a limited spectrum of antibiotic classes. All moderate and strong biofilm producers and 81% of weak biofilm producers were Multidrug Resistance (MDR) strains. In contrast, among non-biofilm producers, only 11.8% were classified as MDR strains. Our results highlighted that Sulfamides and Glycopeptides for the major Gram-positive strains and Fluoroquinolones, Carbapenems, and Aminoglycosides for the most represented Gram-negative isolates could be the most suitable therapeutic choice for most biofilm-DRIs.}, } @article {pmid34425729, year = {2021}, author = {Mokhtar, M and Rismayuddin, NAR and Mat Yassim, AS and Ahmad, H and Abdul Wahab, R and Dashper, S and Arzmi, MH}, title = {Streptococcus salivarius K12 inhibits Candida albicans aggregation, biofilm formation and dimorphism.}, journal = {Biofouling}, volume = {37}, number = {7}, pages = {767-776}, doi = {10.1080/08927014.2021.1967334}, pmid = {34425729}, issn = {1029-2454}, mesh = {Biofilms ; Candida albicans ; *Candidiasis ; Humans ; Sex Characteristics ; *Streptococcus salivarius ; }, abstract = {Candida albicans causes candidiasis, particularly in immunocompromised patients. Streptococcus salivarius K12 (K12) is a probiotic isolated from a healthy oral cavity. The study aimed to determine the effect of K12 on C. albicans aggregation, biofilm formation and dimorphism. C. albicans ATCC MYA-4901, acquired immunodeficiency syndrome (AIDS) isolate (ALC2), and oral cancer isolate (ALC3) and K12 were used in the study. All C. albicans strains and K12 were grown in yeast peptone dextrose agar and brain heart infusion agar, respectively, prior to aggregation, biofilm and dimorphism assays. Auto-aggregation of C. albicans MYA-4901 and ALC2 was categorised as high, while the co-aggregation of the strains was low in the presence of K12. C. albicans total cell count decreased significantly when co-cultured with K12 compared with monocultured C. albicans biofilm (p < 0.05). Inhibition of yeast-to-hyphae transition was also observed when co-cultured with K12. In conclusion, K12 inhibits C. albicans aggregation, biofilm formation and dimorphism.}, } @article {pmid34425432, year = {2022}, author = {Wu, C and Zhou, L and Zhou, C and Zhou, Y and Xia, S and Rittmann, BE}, title = {Co-removal of 2,4-dichlorophenol and nitrate using a palladized biofilm: Denitrification-promoted microbial mineralization following catalytic dechlorination.}, journal = {Journal of hazardous materials}, volume = {422}, number = {}, pages = {126916}, doi = {10.1016/j.jhazmat.2021.126916}, pmid = {34425432}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors ; Chlorophenols ; *Denitrification ; *Nitrates ; Phenols ; }, abstract = {The effects of nitrate on 2,4-dichlorophenol (2,4-DCP) dechlorination and biodegradation in a hydrogen (H2)-based palladized membrane biofilm reactor (Pd-MBfR) were studied. The Pd-MBfR was created by synthesizing palladium nanoparticle (Pd[0]NPs) that spontaneously associated with the biofilm to form a Pd[0]-biofilm. Without input of nitrate, the Pd-MBfR had rapid and stable catalytic hydrodechlorination: 93% of the 100-μM influent 2,4-DCP was continuously converted to phenol, part of which was then fermented via acetogenesis and methanogenesis. Introduction of nitrate enabled phenol mineralization via denitrification with only a minor decrease in catalytic hydrodechlorination. Phenol-degrading bacteria capable of nitrate respiration were enriched in the Pd[0]-biofilm, which was dominated by the heterotrophic genera Thauera and Azospira. Because the heterotrophic denitrifiers had greater yields than autotrophic denitrifiers, phenol was a more favorable electron donor than H2 for denitrification. This feature facilitated phenol mineralization and ameliorated denitrification inhibition of catalytic dechlorination through competition for H2. Increased nitrite loading eventually led to deterioration of the dechlorination flux and selectivity toward phenol. This study documents simultaneous removal of 2,4-DCP and nitrate in the Pd-MBfR and interactions between the two reductions.}, } @article {pmid34424754, year = {2021}, author = {Isaka, M and Okamoto, A and Miura, Y and Tatsuno, I and Maeyama, JI and Hasegawa, T}, title = {Streptococcus pyogenes TrxSR Two-Component System Regulates Biofilm Production in Acidic Environments.}, journal = {Infection and immunity}, volume = {89}, number = {11}, pages = {e0036021}, pmid = {34424754}, issn = {1098-5522}, mesh = {Antigens, Bacterial/biosynthesis ; Bacterial Outer Membrane Proteins/biosynthesis ; Bacterial Proteins/genetics/*physiology ; Biofilms/*growth & development ; Carrier Proteins/biosynthesis ; Exotoxins/physiology ; Histidine Kinase/physiology ; Hydrogen-Ion Concentration ; Phosphorylation ; Promoter Regions, Genetic ; Streptococcus pyogenes/*physiology ; }, abstract = {Bacteria form biofilms for their protection against environmental stress and produce virulence factors within the biofilm. Biofilm formation in acidified environments is regulated by a two-component system, as shown by studies on isogenic mutants of the sensor protein of the two-component regulatory system in Streptococcus pyogenes. In this study, we found that the LiaS histidine kinase sensor mediates biofilm production and pilus expression in an acidified environment through glucose fermentation. The liaS isogenic mutant produced biofilms in a culture acidified by hydrochloric acid but not glucose, suggesting that the acidified environment is sensed by another protein. In addition, the trxS isogenic mutant could not produce biofilms or activate the mga promoter in an acidified environment. Mass spectrometry analysis showed that TrxS regulates M protein, consistent with the transcriptional regulation of emm, which encodes M protein. Our results demonstrate that biofilm production during environmental acidification is directly under the control of TrxS.}, } @article {pmid34424745, year = {2021}, author = {Chiang, IL and Wang, Y and Fujii, S and Muegge, BD and Lu, Q and Tarr, PI and Stappenbeck, TS}, title = {Biofilm Formation and Virulence of Shigella flexneri Are Modulated by pH of Gastrointestinal Tract.}, journal = {Infection and immunity}, volume = {89}, number = {11}, pages = {e0038721}, pmid = {34424745}, issn = {1098-5522}, support = {IK2 BX004909/BX/BLRD VA/United States ; P30 CA091842/CA/NCI NIH HHS/United States ; UL1 RR024992/RR/NCRR NIH HHS/United States ; UL1 TR002345/TR/NCATS NIH HHS/United States ; }, mesh = {Base Sequence ; Biofilms/*growth & development ; Deoxycholic Acid/pharmacology ; Gastrointestinal Tract/*metabolism ; Hydrogen-Ion Concentration ; Shigella flexneri/pathogenicity/*physiology ; Transcriptome ; Virulence ; }, abstract = {Shigella infection remains a public health problem in much of the world. Classic models of Shigella pathogenesis suggest that microfold epithelial cells in the small intestine are the preferred initial site of invasion. However, recent evidence supports an alternative model in which Shigella primarily infects a much wider range of epithelial cells that reside primarily in the colon. Here, we investigated whether the luminal pH difference between the small intestine and the colon could provide evidence in support of either model of Shigella flexneri pathogenesis. Because virulence factors culminating in cellular invasion are linked to biofilms in S. flexneri, we examined the effect of pH on the ability of S. flexneri to form and maintain adherent biofilms induced by deoxycholate. We showed that a basic pH (as expected in the small intestine) inhibited formation of biofilms and dispersed preassembled mature biofilms, while an acidic pH (similar to the colonic environment) did not permit either of these effects. To further elucidate this phenomenon at the molecular level, we probed the transcriptomes of biofilms and S. flexneri grown under different pH conditions. We identified specific amino acid (cysteine and arginine) metabolic pathways that were enriched in the bacteria that formed the biofilms but decreased when the pH increased. We then utilized a type III secretion system reporter strain to show that increasing pH reduced deoxycholate-induced virulence of S. flexneri in a dose-dependent manner. Taken together, these experiments support a model in which Shigella infection is favored in the colon because of the local pH differences in these organs.}, } @article {pmid34424588, year = {2022}, author = {Wigley, K and Egbadon, E and Carere, CR and Weaver, L and Baronian, K and Burbery, L and Dupont, PY and Bury, SJ and Gostomski, PA}, title = {RNA stable isotope probing and high-throughput sequencing to identify active microbial community members in a methane-driven denitrifying biofilm.}, journal = {Journal of applied microbiology}, volume = {132}, number = {2}, pages = {1526-1542}, doi = {10.1111/jam.15264}, pmid = {34424588}, issn = {1365-2672}, support = {//Marsden Fund Council, managed by Royal Society Te Apārangi/ ; }, mesh = {Biofilms ; High-Throughput Nucleotide Sequencing ; Isotopes ; *Methane ; *Microbiota/genetics ; Oxidation-Reduction ; Phylogeny ; RNA ; RNA Probes ; RNA, Ribosomal, 16S ; }, abstract = {AIMS: Aerobic methane oxidation coupled to denitrification (AME-D) is a promising process for removing nitrate from groundwater and yet its microbial mechanism and ecological implications are not fully understood. This study used RNA stable isotope probing (RNA-SIP) and high-throughput sequencing to identify the micro-organisms that are actively involved in aerobic methane oxidation within a denitrifying biofilm.

METHODS AND RESULTS: Two RNA-SIP experiments were conducted to investigate labelling of RNA and methane monooxygenase (pmoA) transcripts when exposed to [13] C-labelled methane over a 96-hour time period and to determine active bacteria involved in methane oxidation in a denitrifying biofilm. A third experiment was performed to ascertain the extent of [13] C labelling of RNA using isotope ratio mass spectrometry (IRMS). All experiments used biofilm from an established packed bed reactor. IRMS confirmed [13] C enrichment of the RNA. The RNA-SIP experiments confirmed selective enrichment by the shift of pmoA transcripts into heavier fractions over time. Finally, high-throughput sequencing identified the active micro-organisms enriched with [13] C.

CONCLUSIONS: Methanotrophs (Methylovulum spp. and Methylocystis spp.), methylotrophs (Methylotenera spp.) and denitrifiers (Hyphomicrobium spp.) were actively involved in AME-D.

This is the first study to use RNA-SIP and high-throughput sequencing to determine the bacteria active within an AME-D community.}, } @article {pmid34424483, year = {2021}, author = {Suner, SS and Sahiner, M and Ayyala, RS and Bhethanabotla, VR and Sahiner, N}, title = {Versatile Fluorescent Carbon Dots from Citric Acid and Cysteine with Antimicrobial, Anti-biofilm, Antioxidant, and AChE Enzyme Inhibition Capabilities.}, journal = {Journal of fluorescence}, volume = {31}, number = {6}, pages = {1705-1717}, pmid = {34424483}, issn = {1573-4994}, mesh = {Acetylcholinesterase/metabolism ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antioxidants/chemical synthesis/chemistry/*pharmacology ; Benzothiazoles/antagonists & inhibitors ; Biofilms/drug effects ; Carbon/chemistry/pharmacology ; Cholinesterase Inhibitors/chemical synthesis/chemistry/*pharmacology ; Citric Acid/chemistry/*pharmacology ; Cysteine/chemistry/*pharmacology ; Fluorescent Dyes/chemical synthesis/chemistry/*pharmacology ; Humans ; Pseudomonas aeruginosa/drug effects ; Quantum Dots/chemistry ; Staphylococcus aureus/drug effects ; Sulfonic Acids/antagonists & inhibitors ; }, abstract = {Nanostructured fluorescent particles derived from natural molecules were prepared by a green synthesis technique employing a microwave method. The precursors citric acid (CA) and cysteine (Cys) were used in the preparation of S- and N-doped Cys carbon dots (Cys CDs). Synthesis was completed in 3 min. The graphitic structure revealed by XRD analysis of Cys CDs dots had good water dispersity, with diameters in the range of 2-20 nm determined by TEM analysis. The isoelectric point of the S, N-doped CDs was pH value for 5.2. The prepared Cys CDs displayed excellent fluorescence intensity with a high quantum yield of 75.6 ± 2.1%. Strong antimicrobial capability of Cys CDs was observed with 12.5 mg/mL minimum bactericidal concentration (MBC) against gram-positive and gram-negative bacteria with the highest antimicrobial activity obtained against Staphylococcus aureus. Furthermore, Cys CDs provided total biofilm eradication and inhibition abilities against Pseudomonas aeruginosa at 25 mg/mL concentration. Cys CDs are promising antioxidant materials with 1.3 ± 0.1 μmol Trolox equivalent/g antioxidant capacity. Finally, Cys CDs were also shown to inhibit the acetylcholinesterase (AChE) enzyme, which is used in the treatment of Alzheimer's disease, even at the low concentration of 100 μg/mL.}, } @article {pmid34424316, year = {2021}, author = {da Silva, GO and Farias, BCS and da Silva, RB and Teixeira, EH and Cordeiro, RA and Hissa, DC and Melo, VMM}, title = {Effects of lipopeptide biosurfactants on clinical strains of Malassezia furfur growth and biofilm formation.}, journal = {Medical mycology}, volume = {59}, number = {12}, pages = {1191-1201}, doi = {10.1093/mmy/myab051}, pmid = {34424316}, issn = {1460-2709}, support = {407754/2013-0//National Council for Scientific and Technological Development/ ; //FUNCAP/ ; }, mesh = {Animals ; Antifungal Agents/pharmacology ; Biofilms ; Lipopeptides/pharmacology ; *Malassezia ; Mice ; Microbial Sensitivity Tests/veterinary ; }, abstract = {Lipopeptide biosurfactants (LBs) are biological molecules with low toxicity that have aroused growing interest in the pharmaceutical industry. Their chemical structure confers antimicrobial and antibiofilm properties against different species. Despite their potential, few studies have demonstrated their capability against Malassezia spp., commensal yeasts which can cause dermatitis and serious infections. Thus, the aim of this study was to evaluate the antifungal activity of biosurfactants produced by new strains of Bacillus subtilis TIM10 and B. vallismortis TIM68 against M. furfur and their potential for removal and inhibition of yeast biofilms. Biosurfactants were classified as lipopeptides by FTIR, and their composition was characterized by ESI-Q-TOF/MS, showing ions for iturin, fengycin, and surfactin, with a greater abundance of surfactin. Through the broth microdilution method, both biosurfactants inhibited the growth of clinical M. furfur strains. Biosurfactant TIM10 showed greater capacity for growth inhibition, with no statistical difference compared to those obtained by the commercial antifungal fluconazole for M. furfur 153DR5 and 154DR8 strains. At minimal inhibitory concentrations (MIC-2), TIM10 and TIM68 were able to inhibit biofilm formation, especially TIM10, with an inhibition rate of approximately 90%. In addition, both biosurfactants were able to remove pre-formed biofilm. Both biosurfactants showed no toxicity against murine fibroblasts, even at concentrations above MIC-2. Our results show the effectiveness of LBs in controlling the growth and biofilm formation of M. furfur clinical strains and highlight the potential of these agents to compose new formulations for the treatment of these fungi.}, } @article {pmid34424229, year = {2021}, author = {Redman, WK and Welch, GS and Rumbaugh, KP}, title = {Assessing Biofilm Dispersal in Murine Wounds.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {174}, pages = {}, doi = {10.3791/62136}, pmid = {34424229}, issn = {1940-087X}, mesh = {Animals ; Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Extracellular Polymeric Substance Matrix ; Mice ; Pseudomonas aeruginosa ; *Wound Infection ; }, abstract = {Biofilm-related infections are implicated in a wide array of chronic conditions such as non-healing diabetic foot ulcers, chronic sinusitis, reoccurring otitis media, and many more. Microbial cells within these infections are protected by an extracellular polymeric substance (EPS), which can prevent antibiotics and host immune cells from clearing the infection. To overcome this obstacle, investigators have begun developing dispersal agents as potential therapeutics. These agents target various components within the biofilm EPS, weakening the structure, and initiating dispersal of the bacteria, which can theoretically improve antibiotic potency and immune clearance. To determine the efficacy of dispersal agents for wound infections, we have developed protocols that measure biofilm dispersal both ex vivo and in vivo. We use a mouse surgical excision model that has been well-described to create biofilm-associated chronic wound infections. To monitor dispersal in vivo, we infect the wounds with bacterial strains that express luciferase. Once mature infections have established, we irrigate the wounds with a solution containing enzymes that degrade components of the biofilm EPS. We then monitor the location and intensity of the luminescent signal in the wound and filtering organs to provide information about the level of dispersal achieved. For ex vivo analysis of biofilm dispersal, infected wound tissue is submerged in biofilm-degrading enzyme solution, after which the bacterial load remaining in the tissue, versus the bacterial load in solution, is assessed. Both protocols have strengths and weaknesses and can be optimized to help accurately determine the efficacy of dispersal treatments.}, } @article {pmid34422678, year = {2021}, author = {Rahmoun, LA and Azrad, M and Peretz, A}, title = {Antibiotic Resistance and Biofilm Production Capacity in Clostridioides difficile.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {683464}, pmid = {34422678}, issn = {2235-2988}, mesh = {Biofilms ; *Clostridioides ; *Clostridioides difficile ; Drug Resistance, Microbial ; Humans ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Clostridioides difficile (C. difficile) is one of the primary pathogens responsible for infectious diarrhea. Antibiotic treatment failure, occurring in about 30% of patients, and elevated rates of antibiotic resistance pose a major challenge for therapy. Reinfection often occurs by isolates that produce biofilm, a protective barrier impermeable to antibiotics. We explored the association between antibiotic resistance (in planktonic form) and biofilm-production in 123 C. difficile clinical isolates.

RESULTS: Overall, 66 (53.6%) out of 123 isolates produced a biofilm, with most of them being either a strong (44%) or moderate (34.8%) biofilm producers. When compared to susceptible isolates, a statistically higher percentage of isolates with reduced susceptibility to metronidazole or vancomycin were biofilm producers (p < 0.0001, for both antibiotics). Biofilm production intensity was higher among tolerant isolates; 53.1% of the metronidazole-susceptible isolates were not able to produce biofilms, and only 12.5% were strong biofilm-producers. In contrast, 63% of the isolates with reduced susceptibility had a strong biofilm-production capability, while 22.2% were non-producers. Among the vancomycin-susceptible isolates, 51% were unable to produce biofilms, while all the isolates with reduced vancomycin susceptibility were biofilm-producers. Additionally, strong biofilm production capacity was more common among the isolates with reduced vancomycin susceptibility, compared to susceptible isolates (72.7% vs. 18.8%, respectively). The distribution of biofilm capacity groups was statistically different between different Sequence-types (ST) strains (p =0.001). For example, while most of ST2 (66.7%), ST13 (60%), ST42 (80%) isolates were non-producers, most (75%) ST6 isolates were moderate producers and most of ST104 (57.1%) were strong producers.

CONCLUSIONS: Our results suggest an association between reduced antibiotic susceptibility and biofilm production capacity. This finding reinforces the importance of antibiotic susceptibility testing, mainly in recurrence infections that may be induced by a strain that is both antibiotic tolerant and biofilm producer. Better adjustment of treatment in such cases may reduce recurrences rates and complications. The link of biofilm production and ST should be further validated; if ST can indicate on isolate virulence, then in the future, when strain typing methods will be more available to laboratories, ST determination may aid in indecision between supportive vs. aggressive treatment.}, } @article {pmid34422235, year = {2021}, author = {Damiano, P and Salema, EJ and Silago, V}, title = {The susceptibility of multidrug resistant and biofilm forming Klebsiella pneumoniae and Escherichia coli to antiseptic agents used for preoperative skin preparations at zonal referral hospital in Mwanza, Tanzania.}, journal = {Malawi medical journal : the journal of Medical Association of Malawi}, volume = {33}, number = {1}, pages = {59-64}, pmid = {34422235}, issn = {1995-7270}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Anti-Infective Agents, Local/*pharmacology/therapeutic use ; Bacteria/classification/drug effects/genetics/isolation & purification ; Biofilms ; Cross-Sectional Studies ; Drug Resistance, Multiple/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Escherichia coli/*drug effects/isolation & purification ; Escherichia coli Infections/drug therapy/microbiology ; Gram-Negative Bacteria/drug effects/isolation & purification ; Humans ; Klebsiella Infections/drug therapy ; Klebsiella pneumoniae/*drug effects/isolation & purification ; Microbial Sensitivity Tests ; Tanzania ; }, abstract = {BACKGROUND: Non-susceptibility of bacteria to antiseptic agents used for preoperative skin preparations threaten the effectiveness of prevention of surgical site infections. Data concerning susceptibility of multidrug resistant bacteria strains to antiseptic agents was limited at our setting. This study presents the susceptibility of extended spectrum β-lactamases producing Klebsiella pneumoniae and Escherichia coli (with and without biofilm formation) to antiseptic agents used for preoperative skin preparations at zonal referral hospital in Mwanza, Tanzania.

METHODS: This cross-sectional descriptive study was conducted through July 2020. Presumptive extended spectrum beta-lactamase producing Klebsiella pneumoniae and Escherichia coli were recovered for this study. Disc combination method was used to confirm production of ESBL while tube method was used to detect biofilms formation. Then, isolates were tested for susceptibility towards 10% povidone iodine, 70% methylated spirit, 50% hydrogen peroxide (6% of industrial H2O2 diluted in equal volume with sterile distilled water) and 2% chlorhexidine. STATA software version 13.0 was used for data analysis.

RESULTS: A total of 31 presumptive ESBL producers were recovered and phenotypically confirmed, whereas 54.8% (n=17) were K. pneumoniae and 45.2% (n=14) were E. coli. Five (35.7%) E. coli and seven (41.2%) K. pneumoniae had positive biofilms test results. Four (12.9%) bacteria were non-susceptible to antiseptic agents used for preoperative skin preparations. However, none exhibited resistance towards 10% PVP-I.

CONCLUSION: In this study we highlight the existence of multidrug resistant Gram-negative bacteria with resistance to antiseptic agents used for preoperative skin preparation at a zonal referral hospital in Mwanza, Tanzania.}, } @article {pmid34421883, year = {2021}, author = {Tran, T and Grandvalet, C and Winckler, P and Verdier, F and Martin, A and Alexandre, H and Tourdot-Maréchal, R}, title = {Shedding Light on the Formation and Structure of Kombucha Biofilm Using Two-Photon Fluorescence Microscopy.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {725379}, pmid = {34421883}, issn = {1664-302X}, abstract = {Kombucha pellicles are often used as inoculum to produce this beverage and have become a signature feature. This cellulosic biofilm produced by acetic acid bacteria (AAB) involves yeasts, which are also part of the kombucha consortia. The role of microbial interactions in the de novo formation and structure of kombucha pellicles was investigated during the 3 days following inoculation, using two-photon microscopy coupled with fluorescent staining. Aggregated yeast cells appear to serve as scaffolding to which bacterial cellulose accumulates. This initial foundation leads to a layered structure characterized by a top cellulose-rich layer and a biomass-rich sublayer. This sublayer is expected to be the microbiologically active site for cellulose production and spatial optimization of yeast-AAB metabolic interactions. The pellicles then grow in thickness while expanding their layered organization. A comparison with pellicles grown from pure AAB cultures shows differences in consistency and structure that highlight the impact of yeasts on the structure and properties of kombucha pellicles.}, } @article {pmid34421879, year = {2021}, author = {Cron, B and Macalady, JL and Cosmidis, J}, title = {Organic Stabilization of Extracellular Elemental Sulfur in a Sulfurovum-Rich Biofilm: A New Role for Extracellular Polymeric Substances?.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {720101}, pmid = {34421879}, issn = {1664-302X}, abstract = {This work shines light on the role of extracellular polymeric substance (EPS) in the formation and preservation of elemental sulfur biominerals produced by sulfur-oxidizing bacteria. We characterized elemental sulfur particles produced within a Sulfurovum-rich biofilm in the Frasassi Cave System (Italy). The particles adopt spherical and bipyramidal morphologies, and display both stable (α-S8) and metastable (β-S8) crystal structures. Elemental sulfur is embedded within a dense matrix of EPS, and the particles are surrounded by organic envelopes rich in amide and carboxylic groups. Organic encapsulation and the presence of metastable crystal structures are consistent with elemental sulfur organomineralization, i.e., the formation and stabilization of elemental sulfur in the presence of organics, a mechanism that has previously been observed in laboratory studies. This research provides new evidence for the important role of microbial EPS in mineral formation in the environment. We hypothesize that the extracellular organics are used by sulfur-oxidizing bacteria for the stabilization of elemental sulfur minerals outside of the cell wall as a store of chemical energy. The stabilization of energy sources (in the form of a solid electron acceptor) in biofilms is a potential new role for microbial EPS that requires further investigation.}, } @article {pmid34421847, year = {2021}, author = {Yang, D and Hao, S and Zhao, L and Shi, F and Ye, G and Zou, Y and Song, X and Li, L and Yin, Z and He, X and Feng, S and Chen, H and Zhang, Y and Gao, Y and Li, Y and Tang, H}, title = {Paeonol Attenuates Quorum-Sensing Regulated Virulence and Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {692474}, pmid = {34421847}, issn = {1664-302X}, abstract = {With the prevalence of multidrug-resistant bacteria and clinical -acquired pathogenic infections, the development of quorum-sensing (QS) interfering agents is one of the most potential strategies to combat bacterial infections and antibiotic resistance. Chinese herbal medicines constitute a valuable bank of resources for the identification of QS inhibitors. Accordingly, in this research, some compounds were tested for QS inhibition using indicator strains. Paeonol is a phenolic compound, which can effectively reduce the production of violacein without affecting its growth in Chromobacterium violaceum ATCC 12472, indicating its excellent anti-QS activity. This study assessed the anti-biofilm activity of paeonol against Gram-negative pathogens and investigated the effect of paeonol on QS-regulated virulence factors in Pseudomonas aeruginosa. A Caenorhabditis elegans infection model was used to explore the anti-infection ability of paeonol in vivo. Paeonol exhibited an effective anti-biofilm activity against Gram-negative bacteria. The ability of paeonol to interfere with the AHL-mediated quorum sensing systems of P. aeruginosa was determined, found that it could attenuate biofilm formation, and synthesis of pyocyanin, protease, elastase, motility, and AHL signaling molecule in a concentration- and time-dependent manner. Moreover, paeonol could significantly downregulate the transcription level of the QS-related genes of P. aeruginosa including lasI/R, rhlI/R, pqs/mvfR, as well as mediated its virulence factors, lasA, lasB, rhlA, rhlC, phzA, phzM, phzH, and phzS. In vivo studies revealed that paeonol could reduce the pathogenicity of P. aeruginosa and enhance the survival rate of C. elegans, showing a moderate protective effect on C. elegans. Collectively, these findings suggest that paeonol attenuates bacterial virulence and infection of P. aeruginosa and that further research elucidating the anti-QS mechanism of this compound in vivo is warranted.}, } @article {pmid34419054, year = {2021}, author = {Abdelraheem, WM and Khairy, RMM and Zaki, AI and Zaki, SH}, title = {Effect of ZnO nanoparticles on methicillin, vancomycin, linezolid resistance and biofilm formation in Staphylococcus aureus isolates.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {20}, number = {1}, pages = {54}, pmid = {34419054}, issn = {1476-0711}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Anti-Infective Agents ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Linezolid/pharmacology ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Pseudomonas aeruginosa/drug effects ; Reverse Transcriptase Polymerase Chain Reaction ; Staphylococcus aureus/*drug effects/genetics/isolation & purification ; Vancomycin/pharmacology ; Vancomycin Resistance/*drug effects/genetics ; Zinc Oxide/*chemistry/pharmacology ; }, abstract = {BACKGROUND: Multidrug resistant (MDR) and biofilm producing Staphylococcus aureus strains are usually associated with serious infections. This study aimed to evaluate the antibacterial and antibiofilm-formation effects of zinc oxide nanoparticles (ZnO-NPs) against staphylococcus aureus (S. aureus) isolates.

METHODS: A total of 116 S. aureus isolates were recovered from 250 burn wound samples. The antimicrobial/antibiofilm effects of ZnO-NPs against methicillin, vancomycin and linezolid resistant S. aureus (MRSA, VRSA and LRSA) isolates were examined using phenotypic and genotypic methods. The minimum inhibitory concentration (MIC) of ZnO-NPs was determined by microdilution method. The effects of sub-MIC concentrations of ZnO-NPs on biofilm formation and drug resistance in S. aureus were determined by the microtiter plate method. The change in the expression levels of the biofilm encoding genes and resistance genes in S. aureus isolates after treatment with ZnO-NPs was assessed by real time reverse transcriptase PCR (rt-PCR).

RESULTS: MICs of ZnO-NPs in S. aureus isolates were (128-2048 µg/ml). The sub-MIC of ZnO-NPs significantly reduced biofilm formation rate (the highest inhibition rate was 76.47% at 1024  µg/ml) and the expression levels of biofilm genes (ica A, ica D and fnb A) with P < 0.001. Moreover, Sub-MIC of ZnO-NPs significantly reduced the rates of MRSA from 81.9 (95 isolates) to 13.30% (15 isolates), VRSA from 33.60 (39 isolates) to 0% and LARSA from 29.30 (34) to 0% as well as the expression levels of resistance genes (mec A, van A and cfr) with P value < 0.001.

CONCLUSION: ZnO-NPs can be used as antibiofilm and potent antimicrobial against MRSA, VRSA and LRSA isolates.}, } @article {pmid34418664, year = {2022}, author = {Barathi, S and Aruljothi, KN and Karthik, C and Padikasan, IA and Ashokkumar, V}, title = {Biofilm mediated decolorization and degradation of reactive red 170 dye by the bacterial consortium isolated from the dyeing industry wastewater sediments.}, journal = {Chemosphere}, volume = {286}, number = {Pt 3}, pages = {131914}, doi = {10.1016/j.chemosphere.2021.131914}, pmid = {34418664}, issn = {1879-1298}, mesh = {Azo Compounds ; Biodegradation, Environmental ; Biofilms ; *Brevibacillus ; *Coloring Agents ; Textile Industry ; Wastewater ; }, abstract = {Reactive dyes are extensively used in a plethora of industries, which in turn release toxic wastes into the environment. The textile dye waste remediation is crucial as it may contain several toxic elements. The utilization of bacterial consortium for bioremediation has acquired consideration, over the utilization of single strains. In this study, a microbial consortium containing three bacterial sp. (Bacillus subtilis, Brevibacillus borstelensis and Bacillus firmus) was tested for its degrading ability of the textile RR 170 dye. The bacterial consortium degraded the dye effectively at lower concentrations and the efficiency decreased as the dye concentration increased. SEM analysis revealed that, with dye treatment, the consortium appeared as tightly packed clumps with rough cell surface and were able to produce EPS and biofilms. EPS production was higher at 40 mg/l, 100 mg/l and 200 mg/l of the dye treatment conditions. Interestingly, the maximum biofilm formation was observed only at 40 μg/ml of the dye treatment, which indicates that RR 170 dye concentration affects the biofilm formation independent of EPS levels. The UV-vis spectroscopy, HPLC, FTIR and 2D-FTIR analyses confirmed the decolorization and biodegradation of RR 170 dye by the bacterial consortium. Toxicological studies performed with the dye and their degraded products in Allium cepa root cells revealed that, whereas the RR 170 dye induced genotoxic stress, the degraded dye products showed no significant genotoxic effects in root cells. Together, the investigated bacterial consortium decolorized and degraded the RR 170 dye resulting in metabolites that are non-toxic to the living cells.}, } @article {pmid34418114, year = {2021}, author = {Hoedke, D and Kaulika, N and Dommisch, H and Schlafer, S and Shemesh, H and Bitter, K}, title = {Reduction of dual-species biofilm after sonic- or ultrasonic-activated irrigation protocols: A laboratory study.}, journal = {International endodontic journal}, volume = {54}, number = {12}, pages = {2219-2228}, doi = {10.1111/iej.13618}, pmid = {34418114}, issn = {1365-2591}, support = {5-2015//Forschungsgemeinschaft Dental/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Humans ; Laboratories ; *Root Canal Irrigants ; Ultrasonics ; }, abstract = {AIM: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study.

METHODOLOGY: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.06 taper). Root canals were inoculated with Enterococcus faecalis and Streptococcus oralis. After 5 days, G1 received combined instrumentation (up to size 40, 0.06 taper) and irrigation/activation, whereas G2 received solely irrigation/activation protocols. In both groups, irrigation was performed with sodium hypochlorite (NaOCl 1%) or physiological saline (NaCl 0.9%), using nonactivated syringe irrigation, sonic activation (2 x 30 s) or ultrasonic activation (2 x 30 s). Logarithmic reduction factors (LRFs) of colony-forming units were analysed separately for dentine-adherent and planktonic bacteria immediately after irrigation/activation protocols (time-point 1) or after 5 days of further incubation (time-point 2) by analysis of variance (anova) and post hoc tests (Tukey's HSD, t-test). The significance level was set at 0.05.

RESULTS: In G1 subgroups (combined instrumentation with irrigation/activation), LRFs were significantly affected by the applied irrigation solution (p < .0001), but not by the activation method (p > .05; anova). In G2 subgroups (solely irrigation/activation), both, irrigant solution and activation, significantly affected LRFs (p < .0001, anova). Sonic activation resulted in significantly higher LRFs than ultrasonic activation (p < .0001) which had significantly greater reductions than nonactivated irrigation (p < .05; Tukey's HSD). At T2, strong bacterial regrowth was observed in all groups; however, a significant bacterial reduction was detected for factors instrumentation, irrigant solution and activation (p < .0001; anova). Similar LRFs were found for dentine-adherent and planktonic bacterial cells in all groups (r = 0.91 at T1, r = 0.8 at T2).

CONCLUSIONS: In this laboratory study on extracted maxillary anterior teeth high-frequency sonic activation resulted in a greater bacterial reduction compared to ultrasonic activation in groups receiving solely irrigation/activation protocols; however, irrigation using NaOCl and ultrasonic activation also contributed significantly to bacterial reduction compared to the control groups.}, } @article {pmid34416851, year = {2021}, author = {Zhang, Y and Fan, B and Luo, Y and Tao, Z and Nie, Y and Wang, Y and Ding, F and Li, Y and Gu, D}, title = {Comparative analysis of carbapenemases, RND family efflux pumps and biofilm formation potential among Acinetobacter baumannii strains with different carbapenem susceptibility.}, journal = {BMC infectious diseases}, volume = {21}, number = {1}, pages = {841}, pmid = {34416851}, issn = {1471-2334}, support = {No. JCYJ20190806164011195//Basic research project of Shenzhen Science and technology innovation Commission/ ; }, mesh = {*Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacterial Proteins/genetics ; Biofilms ; Carbapenems/pharmacology ; Cell Division ; Microbial Sensitivity Tests ; beta-Lactamases/genetics ; }, abstract = {AIM: This study has conducted a comparative analysis of common carbapenemases harboring, the expression of resistance-nodulation-cell division (RND) family efflux pumps, and biofilm formation potential associated with carbapenem resistance among Acinetobacter baumannii (A. baumannii) strains with different carbapenem susceptibility.

METHODS: A total of 90 isolates of A. baumannii from two tertiary hospitals of China were identified and grouped as carbapenem susceptible A. baumannii (CSAB) strains and carbapenem non-susceptible A. baumannii (CnSAB) strains based on the susceptibility to imipenem. Harboring of carbapenemase genes, relative expression of RND family efflux pumps and biofilm formation potential were compared between the two groups.

RESULT: Among these strains, 12 (13.3 %) strains were divided into the CSAB group, and 78 (86.7 %) strains into the CnSAB group. Compared with CSAB strains, CnSAB strains increased distribution of blaOXA-23 (p < 0.001) and ISAba1/blaOXA-51-like (p = 0.034) carbapenemase genes, and a 6.1-fold relative expression of adeB (p = 0.002), while CSAB strains led to biofilm formation by 1.3-fold than CnSAB strains (p = 0.021).

CONCLUSIONS: Clinically, harboring more blaOXA-23-like and ISAba1/blaOXA-51-like complex genes and overproduction of adeABC are relevant with carbapenem resistance, while carbapenem susceptible strains might survive the stress of antibiotic through their ability of higher biofilm formation.}, } @article {pmid34416689, year = {2022}, author = {Zhou, Y and Li, R and Guo, B and Xia, S and Liu, Y and Rittmann, BE}, title = {The influent COD/N ratio controlled the linear alkylbenzene sulfonate biodegradation and extracellular polymeric substances accumulation in an oxygen-based membrane biofilm reactor.}, journal = {Journal of hazardous materials}, volume = {422}, number = {}, pages = {126862}, doi = {10.1016/j.jhazmat.2021.126862}, pmid = {34416689}, issn = {1873-3336}, mesh = {Alkanesulfonic Acids ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; *Extracellular Polymeric Substance Matrix ; *Oxygen ; }, abstract = {This work evaluated the fates of linear alkylbenzene sulfonate (LAS), chemical oxygen demand (COD), ammonia nitrogen (NH4[+]-N), and total nitrogen (TN) when treating greywater (GW) in an oxygen-based membrane biofilm reactor (O2-MBfR). An influent ratio of chemical oxygen demand to total nitrogen (COD/TN) of 20 g COD/g N gave the best removals of LAS, COD, NH4[+]-N and TN, and it also had the greatest EPS accumulation in the biofilm. Higher EPS and improved performance were linked to increases in the relative abundances of bacteria able to biodegrade LAS (Zoogloea, Pseudomonas, Parvibaculum, Magnetospirillum and Mycobacterium) and to nitrify (Nitrosomonas and Nitrospira), as well as to ammonia oxidation related enzyme (ammonia monooxygenase). The EPS was dominated by protein, which played a key role in adsorbing LAS, achieving short-time protection from LAS toxicity and allowed LAS biodegradation. Continuous high-efficiency removal of LAS alleviated LAS toxicity to microbial physiological functions, including nitrification, nitrate respiration, the tricarboxylic acid (TCA) cycle, and adenosine triphosphate (ATP) production, achieving the stable high-efficient simultaneous removal of organics and nitrogen in the O2-MBfR.}, } @article {pmid34415760, year = {2021}, author = {Yuan, S and Xu, R and Wang, D and Lin, Q and Zhou, S and Lin, J and Xia, L and Fu, Y and Gan, Z and Meng, F}, title = {Ecological Linkages between a Biofilm Ecosystem and Reactor Performance: The Specificity of Biofilm Development Phases.}, journal = {Environmental science & technology}, volume = {55}, number = {17}, pages = {11948-11960}, doi = {10.1021/acs.est.1c02486}, pmid = {34415760}, issn = {1520-5851}, mesh = {Biofilms ; Bioreactors ; *Ecosystem ; *Extracellular Polymeric Substance Matrix ; Quorum Sensing ; RNA, Ribosomal, 16S/genetics ; }, abstract = {In biofilm-based engineered ecosystems, the reactor performance was closely linked to interspecies interactions within a biofilm ecosystem, whereas the ecological processes underpinning such linkage were still unenlightened. Herein, the principles of community succession and assembly were integrated to capture the ecological laws of biofilm development by molecular ecological networks and assembly model analysis based on the 16S rRNA sequencing analysis and metagenomics in a well-controlled moving bed biofilm reactor. At the initial colonization phase (days 0-2, driven by initial colonizers), interspecific cooperation (74.18%) facilitated initial biofilm formation, whereas some pioneers, and keystone species disappeared at later phases. At the accumulation phase (days 3-30, rapid biofilm development), interspecific cooperation (81.41 ± 5.07%) contributed to rapid biofilm development and keystone species were mainly involved in quorum sensing or positively correlated with extracellular polymeric substance production. At the maturation phase (days 31-106, a well-adapted quasi-equilibrium state), increased interspecific competition (32.74 ± 4.77%) and higher small-world property facilitated the rapid information transportation and pollutant treatment, and keystone species were positively correlated with the removal of COD and NH4[+]-N. Homogenizing dispersal diminished the contemporary community dissimilarities, while turnover but rather nestedness governed the temporal variations in the biofilm succession period. This study highlighted the specificity of ecological processes at distinct biofilm development phases, which would advance our understanding on the development-to-function linkages in biofilm-based treatment processes.}, } @article {pmid34414776, year = {2021}, author = {Warrier, A and Satyamoorthy, K and Murali, TS}, title = {Quorum-sensing regulation of virulence factors in bacterial biofilm.}, journal = {Future microbiology}, volume = {16}, number = {}, pages = {1003-1021}, doi = {10.2217/fmb-2020-0301}, pmid = {34414776}, issn = {1746-0921}, mesh = {*Bacterial Infections/microbiology ; Biofilms ; Humans ; Persistent Infection ; Pseudomonas aeruginosa ; *Quorum Sensing ; Staphylococcus aureus ; *Virulence Factors ; }, abstract = {Chronic polymicrobial wound infections are often characterized by the presence of bacterial biofilms. They show considerable structural and functional heterogeneity, which influences the choice of antimicrobial therapy and wound healing dynamics. The hallmarks of biofilm-associated bacterial infections include elevated antibiotic resistance and extreme pathogenicity. Biofilm helps bacteria to evade the host defense mechanisms and persist longer in the host. Quorum-sensing (QS)-mediated cell signaling primarily regulates biofilm formation in chronic infections and plays a major role in eliciting virulence. This review focuses on the QS mechanisms of two major bacterial pathogens, Staphylococcus aureus and Pseudomonas aeruginosa and explains how they interact in the wound microenvironment to regulate biofilm development and virulence. The review also provides an insight into the treatment modalities aimed at eradicating polymicrobial biofilms. This information will help us develop better diagnostic modalities and devise effective treatment regimens to successfully manage and overcome severe life-threatening bacterial infections.}, } @article {pmid34414738, year = {2021}, author = {Yu, LF and Zhang, XX and Zhang, Q and Wang, XY and Peng, DC and Zhang, RX}, title = {[Characteristics of Partial Denitrification in Biofilm System].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {42}, number = {9}, pages = {4390-4398}, doi = {10.13227/j.hjkx.202102063}, pmid = {34414738}, issn = {0250-3301}, mesh = {Biofilms ; *Bioreactors ; *Denitrification ; Nitrogen ; Oxidation-Reduction ; }, abstract = {As an intermediate form of microbial denitrification, nitrite serves as a key substrate for anaerobic ammonium oxidation (ANAMMOX). This study investigated the partial dentification (PD) characteristics and the coupling feasibility of PD+ANAMMOX in the biofilm system, using a moving bed biofilm reactor which was operated for 120 days. After 40 days of operation with a C/N ratio of 3.0 and filling fraction of 20%, the nitrate-to-nitrite transformation ratio (NTR) reached (69.38±3.53)%, and enzymatic assays indicated that the activities of nitrate reductase (NAR) had increased from 0.03 to 0.45 μmol·(min·mg)[-1] while the activities of nitrite reductase (NIR) had decreased from 0.18 to 0.02 μmol·(min·mg)[-1]. Illumina high-throughput sequencing analysis revealed that the proportion of genus of Thauera bacteria to total microorganism increased from 0.3% (d1) to 37.27% (d64). Finally, the effluent had a total nitrogen (TN) concentration of (6.41±1.50) mg·L[-1], indicating a total nitrogen removal ratio of (88.16±2.71)% and confirming the feasibility of PD+ANAMMOX in the biofilm system.}, } @article {pmid34412706, year = {2021}, author = {Perry, TW}, title = {Cutaneous microbial biofilm formation as an underlying cause of red scrotum syndrome.}, journal = {European journal of medical research}, volume = {26}, number = {1}, pages = {95}, pmid = {34412706}, issn = {2047-783X}, mesh = {Administration, Cutaneous ; Adult ; Antipruritics/administration & dosage/therapeutic use ; *Biofilms ; Erythema/drug therapy/microbiology/*pathology ; Hair Follicle/microbiology ; Humans ; Male ; Menthol/administration & dosage/therapeutic use ; Scrotum/microbiology/*pathology ; }, abstract = {BACKGROUND: Red scrotum syndrome is typically described as well-demarcated erythema of the anterior scrotum accompanied by persistent itching and burning. It is chronic and difficult to treat and contributes to significant psychological distress and reduction in quality of life. The medical literature surrounding the condition is sparse, with the prevalence likely under-recognized and the pathophysiology remaining poorly understood. Formation of a cutaneous microbial biofilm has not been proposed as an underlying etiology. Microbial biofilms can form whenever microorganisms are suspended in fluid on a surface for a prolonged time and are becoming increasingly recognized as important contributors to medical disease (e.g., chronic wounds).

CASE PRESENTATION: A 26-year-old man abruptly developed well-demarcated erythema of the bilateral scrotum after vaginal secretions were left covering the scrotum overnight. For 14 months, the patient experienced daily scrotal itching and burning while seeking care from multiple physicians and attempting numerous failed therapies. He eventually obtained complete symptomatic relief with the twice daily application of 0.8% menthol powder. Findings in support of a cutaneous microbial biofilm as the underlying etiology include: (1) the condition began following a typical scenario that would facilitate biofilm formation; (2) the demarcation of erythema precisely follows the scrotal hairline, suggesting that hair follicles acted as scaffolding during biofilm formation; (3) despite resolution of symptoms, the scrotal erythema has persisted, unchanged in boundary 15 years after the condition began; and (4) the erythematous skin demonstrates prolonged retention of gentian violet dye in comparison with adjacent unaffected skin, suggesting the presence of dye-avid material on the skin surface.

CONCLUSION: The probability that microorganisms, under proper conditions, can form biofilm on intact skin is poorly recognized. This case presents a compelling argument for a cutaneous microbial biofilm as the underlying cause of red scrotum syndrome in one patient, and a review of similarities with other reported cases suggests the same etiology is likely responsible for a significant portion of the total disease burden. This etiology may also be a significant contributor to the disease burden of vulvodynia, a condition with many similarities to red scrotum syndrome.}, } @article {pmid34411997, year = {2021}, author = {Maggio, F and Rossi, C and Chiaverini, A and Ruolo, A and Orsini, M and Centorame, P and Acciari, VA and Chaves López, C and Salini, R and Torresi, M and Serio, A and Pomilio, F and Paparella, A}, title = {Genetic relationships and biofilm formation of Listeria monocytogenes isolated from the smoked salmon industry.}, journal = {International journal of food microbiology}, volume = {356}, number = {}, pages = {109353}, doi = {10.1016/j.ijfoodmicro.2021.109353}, pmid = {34411997}, issn = {1879-3460}, mesh = {Animals ; *Biofilms ; Food Handling ; Food Industry ; *Food Microbiology ; *Listeria monocytogenes/classification/genetics ; Multilocus Sequence Typing ; Salmon/microbiology ; }, abstract = {Among pathogens, L. monocytogenes has the capability to persist on Food Processing Environment (FPE), first of all posing safety issues, then economic impact on productivity. The aim of this work was to determine the influence of biofilm forming-ability and molecular features on the persistence of 19 Listeria monocytogenes isolates obtained from FPE, raw and processed products of a cold-smoked salmon processing plant. To verify the phenotypic and genomic correlations among the isolates, different analyses were employed: serotyping, Clonal Complex (CC), core genome Multi-Locus Sequence Typing (cgMLST) and Single Nucleotide Polymorphisms (SNPs) clustering, and evaluation of the presence of virulence- and persistence-associated genes. From our results, the biofilm formation was significantly higher (*P < 0.05) at 37 °C, compared to 30 and 12 °C, suggesting a temperature-dependent behaviour. Moreover, the biofilm-forming ability showed a strain-specific trend, not correlated with CC or with strains persistence. Instead, the presence of internalin (inL), Stress Survival Islet (SSI) and resistance to erythromycin (ermC) genes was correlated with the ability to produce biofilms. Our data demonstrate that the genetic profile influences the adhesion capacity and persistence of L. monocytogenes in food processing plants and could be the result of environmental adaptation in response to the external selective pressure.}, } @article {pmid34411944, year = {2021}, author = {Feng, Q and Luo, L and Chen, X and Zhang, K and Fang, F and Xue, Z and Li, C and Cao, J and Luo, J}, title = {Facilitating biofilm formation of Pseudomonas aeruginosa via exogenous N-Acy-L-homoserine lactones stimulation: Regulation on the bacterial motility, adhesive ability and metabolic activity.}, journal = {Bioresource technology}, volume = {341}, number = {}, pages = {125727}, doi = {10.1016/j.biortech.2021.125727}, pmid = {34411944}, issn = {1873-2976}, mesh = {Adhesives ; Biofilms ; *Homoserine ; *Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {The N-Acy-L-homoserine lactones (AHLs) mediated quorum sensing (QS) system exhibited important ecological significance in bacterial biofilm formation. However, the previous studies mainly focused on indigenous AHLs while the role of exogenous AHLs has remained unclear. This study evaluated the roles of exogenous AHLs on the biofilm formation of Pseudomonas aeruginosa. Both the C6-HSL and C8-HSL promoted the biofilm formation of P. aeruginosa with an enhancement of 2.47 and 1.88 times, respectively. Further analysis showed that exogenous AHLs contributed greatly to the adhesive ability instead of growth rate. Also, the bacterial motility and metabolic activities were significantly improved by AHLs. Moreover, the microbial functional genes (i.e. lasI, lasR, rhlI and rhlR) involved in regulating the biofilm formation were highly expressed in AHLs reactors. These findings expanded the knowledge of AHLs functions in mediating biofilm formation, and provided insightful guidance on the biofilm regulation in the wastewater treatment via biofilm technology.}, } @article {pmid34411722, year = {2022}, author = {Hsu, JE and Harrison, D and Anderson, K and Huang, C and Whitson, AJ and Matsen, FA and Bumgarner, RE}, title = {Cutibacterium recovered from deep specimens at the time of revision shoulder arthroplasty samples has increased biofilm-forming capacity and hemolytic activity compared with Cutibacterium skin isolates from normal subjects.}, journal = {Journal of shoulder and elbow surgery}, volume = {31}, number = {2}, pages = {318-323}, doi = {10.1016/j.jse.2021.07.010}, pmid = {34411722}, issn = {1532-6500}, mesh = {*Arthroplasty, Replacement, Shoulder ; Biofilms ; Hemolysis ; Humans ; *Propionibacteriaceae ; Skin ; }, abstract = {BACKGROUND: Biofilm formation and hemolytic activity are factors that may correlate with the virulence of Cutibacterium. We sought to compare the prevalence of these potential markers of pathogenicity between Cutibacterium recovered from deep specimens obtained at the time of surgical revision for failed shoulder arthroplasty and Cutibacterium recovered from skin samples from normal subjects.

METHODS: We compared 42 deep-tissue or explant isolates with 43 control Cutibacterium samples obtained from skin isolates from normal subjects. Subtyping information was available for all isolates. Biofilm-forming capacity was measured by inoculating a normalized amount of each isolate onto a 96-well plate. Planktonic bacteria were removed, the remaining adherent bacteria were stained with crystal violet, the crystal violet was re-solubilized in ethyl alcohol, and biofilm-forming capacity was quantitated by optical density (OD). Hemolytic activity was measured by plating a normalized amount of isolate onto agar plates. The area of the colony and the surrounding area of blood lysis were measured and reported as minimal, moderate, or severe hemolysis.

RESULTS: Biofilm-forming capacity was significantly higher in the tissue and explant samples compared with the control skin samples (OD of 0.34 ± 0.30 for deep tissue vs. 0.20 ± 0.28 for skin, P = .002). Hemolytic activity was also significantly higher in the tissue and explant samples than in the control skin samples (P < .0001). Samples with hemolytic activity had significantly higher biofilm-forming capacity compared with samples without hemolytic activity (OD of 0.27 ± 0.29 vs. 0.12 ± 0.15, P = .015). No difference in biofilm-forming capacity or hemolytic activity was found between subtypes.

CONCLUSIONS: Cutibacterium obtained from deep specimens at the time of revision shoulder arthroplasty has higher biofilm-forming capacity and hemolytic activity than Cutibacterium recovered from the skin of normal subjects. These data add support for the view that Cutibacterium harvested from deep tissues may have clinically significant virulence characteristics. The lack of correlation between these clinically relevant phenotypes and subtypes indicates that additional study is needed to identify genotypic markers that better correlate with biofilm and hemolytic activity.}, } @article {pmid34410547, year = {2021}, author = {Koibuchi, H and Fujii, Y and Sato'o, Y and Mochizuki, T and Yamada, T and Cui, L and Taniguchi, N}, title = {Inhibitory effects of ultrasound irradiation on Staphylococcus epidermidis biofilm.}, journal = {Journal of medical ultrasonics (2001)}, volume = {48}, number = {4}, pages = {439-448}, pmid = {34410547}, issn = {1613-2254}, support = {18K18401//the Research and Development JSPS KAKENHI/ ; }, mesh = {Biofilms ; Humans ; *Staphylococcal Infections/prevention & control ; *Staphylococcus epidermidis ; Ultrasonic Waves ; }, abstract = {PURPOSE: We aimed to investigate whether low-intensity continuous and pulsed wave ultrasound (US) irradiation can inhibit the formation of Staphylococcus epidermidis biofilms, for potential application in the treatment of catheter-related bloodstream infections (CRBSI).

METHODS: S. epidermidis biofilms that formed on the bottom surfaces of 6-well plates were irradiated on the bottom surface using the sound cell incubator system for different intervals of time.

RESULTS: US irradiation with continuous waves for 24 h notably inhibited biofilm formation (p < 0.01), but the same US irradiation for 12 h had no remarkable effect. Further, double US irradiation with pulsed waves for 20 min inhibited biofilm formation by 33.6%, nearly two-fold more than single US irradiation, which reduced it by 17.9%.

CONCLUSION: US irradiation of a lower intensity (ISATA = 6-29 mW/cm[2]) than used in a previous study and lower than recommended by the Food and Drug Administration shows potential for preventing CRBSI caused by bacterial biofilms.}, } @article {pmid34409277, year = {2021}, author = {Liu, Y and Zhu, X and Zhao, Q and Yan, X and Du, Q and Li, N and Liao, C and Wang, X}, title = {Synthesis of silver nanoparticles using living electroactive biofilm protected by polydopamine.}, journal = {iScience}, volume = {24}, number = {8}, pages = {102933}, pmid = {34409277}, issn = {2589-0042}, abstract = {The biosynthesis of metal nanoparticles from precious metals has been of wide concern. Their antibacterial activity is a main bottleneck restricting the bacterial activity and reduction performance. Here, bio-electrochemical systems were used to harvest electroactive biofilms (EABs), where bacteria were naturally protected by extracellular polymeric substances to keep activity. The biofilm was further encapsulated with polydopamine (PDA) as additional shield. Silver nanoparticles (AgNPs) were biosynthesized on EABs, whose electroactivity could be fully recovered after Ag[+] reduction. The PDA increased bacterial viability by 90%-105%, confirmed as an effective protection against antibacterial activity of Ag[+]/AgNPs. The biosynthetic process changed the component and function of the microbial community, shifting from bacterial Fe reduction to archaeal methanogenesis. These results demonstrated that the electrochemical acclimation of EABs and encapsulation with PDA were effective protective measures during the biosynthesis of AgNPs. These approaches have a bright future in the green synthesis of nanomaterials, biotoxic wastewater treatment, and sustainable bio-catalysis.}, } @article {pmid34408988, year = {2021}, author = {de Barros, PP and Rossoni, RD and Garcia, MT and Kaminski, VL and Loures, FV and Fuchs, BB and Mylonakis, E and Junqueira, JC}, title = {The Anti-Biofilm Efficacy of Caffeic Acid Phenethyl Ester (CAPE) In Vitro and a Murine Model of Oral Candidiasis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {700305}, pmid = {34408988}, issn = {2235-2988}, mesh = {Animals ; Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; Caffeic Acids ; Candida albicans ; *Candidiasis, Oral/drug therapy ; Disease Models, Animal ; Mice ; Phenylethyl Alcohol/analogs & derivatives ; }, abstract = {Candida albicans is the main fungal species associated with the development of oral candidiasis. Currently, therapeutic options for these infections are limited by the adverse effects of antifungal drugs and by the emergence of drug resistant strains. Thus, the development of new antifungal agents is needed for the prevention and treatment of oral Candida infections. Caffeic acid phenethyl ester (CAPE) is a natural compound from propolis polyphenolic groups that exhibits many pharmacological properties. In this study, we investigated whether CAPE can have antifungal and immunomodulatory effects on oral candidiasis. Preliminary tests to assess the antifungal activity of CAPE were performed using the Minimum Inhibitory Concentration (MIC) assay that demonstrated inhibition in a range from 16 to 32 μg/mL, confirming its antifungal activity on several C. albicans strains isolated from the oral cavity. Subsequently, we analyzed Candida spp biofilms formed in vitro, in which CAPE treatment at 5 x MIC caused a reduction of 68.5% in the total biomass and ~2.60 Log in the viable cell count (CFU/mL) in relation to the untreated biofilm (p<0.0001). Next, RNA was extracted from untreated and CAPE-treated biofilms and analyzed by real-time qPCR. A series of genes analyzed (ALS1, ECE1, EPA1, HWP1, YWP1, BCR1, BGR1, CPH1, EFG1, NDT80, ROB1, TEC1, UME6, SAP2, SAP5, PBL2, and LIP9) were downregulated by CAPE compared to the untreated control group (p<0.0001). In in vivo studies using Galleria mellonella, the treatment with CAPE prolonged survival of larvae infected by C. albicans by 44.5% (p < 0.05) and accompanied by a 2.07-fold increase in the number of hemocytes. Flow cytometry revealed the most prominent increases were in types P2 and P3 hemocytes, granular cells, which phagocytize pathogens. In addition, CAPE treatment decreased the fungal load in the hemolymph and stimulated the expression of antifungal peptide genes such as galiomicin and gallerimycin. The antifungal and immunomodulatory activities observed in G. mellonella were extended to a murine model of oral candidiasis, in which CAPE decreased the levels of C. albicans colonization (~2 log CFU/mL) in relation to the untreated control group. In addition, CAPE treatment significantly reduced pseudomembranous lesions, invasion of hyphae on epithelium surfaces, tissue damage and inflammatory infiltrate (p < 0.05). CAPE was also able to increase the expression of β-defensin 3 compared to the infected and untreated group by 3.91-fold (p < 0.0001). Taken together, these results show that CAPE has both antifungal and immunomodulatory effects, making it a promising natural antifungal agent for the treatment and prevention of candidiasis and shows impact to oral candidiasis.}, } @article {pmid34402278, year = {2021}, author = {Han, F and Yuan, ZT and Liang, XL and Xiong, YK and Yang, M and Ma, GQ}, title = {[Research advances in drug resistance mechanisms of bacterial biofilm and natural drug intervention].}, journal = {Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica}, volume = {46}, number = {14}, pages = {3560-3565}, doi = {10.19540/j.cnki.cjcmm.20210318.601}, pmid = {34402278}, issn = {1001-5302}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/genetics ; *Biofilms ; Drug Resistance ; *Pharmaceutical Preparations ; }, abstract = {Drug resistance resulting from bacterial biofilms can invalidate antibacterial agents. Therefore,eradicating bacterial biofilms to reverse drug resistance is a hotspot in the pharmaceutical research. In recent years,numerous studies have revealed the complicated mechanism of bacterial biofilm formation and strong drug resistance with multiple influential factors involved. This paper gives a comprehensive review on the process of biofilm formation and intervention by natural drugs,which can provide some reference and evidence for the following studies.}, } @article {pmid34402255, year = {2021}, author = {Shui, J and Wang, H and Tao, X and Min, C and Li, J and Zou, M}, title = {Relationship of biofilm-forming ability of with swimming motility, twitching motility and virulence gene distribution.}, journal = {Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences}, volume = {50}, number = {3}, pages = {345-351}, pmid = {34402255}, issn = {1008-9292}, mesh = {*Biofilms ; Humans ; *Swimming ; Virulence/genetics ; }, abstract = {To investigate the relationship of biofilm-forming ability of (PA) with swimming motility, twitching motility and virulence gene distribution. A total of 192 clinical isolates of PA were collected consecutively. Microtiter plate method was used to evaluate the ability to form biofilm. The swimming and twitching motilities were detected by plate method. Polymerase chain reaction (PCR) was used to detect virulence genes. Of the 192 PA clinical isolates, 186 (96.9%) showed biofilm-forming ability. Among them, 36 isolates showed weak biofilm-forming ability, 84 exhibited moderate biofilm-forming ability and 66 showed strong biofilm-forming ability. The diameters of the swimming ring for PA with none biofilm-forming ability, weak biofilm-forming ability, moderate biofilm-forming ability, strong biofilm-forming ability were (9.12±6.76), (18.42±7.51), (19.10±4.77) and respectively. The diameters of the twitching ring for PA in above groups were (8.38±1.50), (17.21±7.42), (18.49±5.62) and respectively. The swimming motility and twitching motility of none biofilm-forming ability group were weaker than biofilm-forming ability groups (all <0.05). Among 192 PA strains, 163 were positive (84.9%), 40 were positive (20.8%), 183 were positive (95.3%), and 189 were positive (98.4%). The positive rate of PA virulence gene , and were different in strains with different biofilm-forming abilities (<0.05). The rate of in the strong biofilm-forming ability group was lower than that in the moderate biofilm-forming ability group (=9.293, <0.01) and the weak biofilm-forming ability group (=9.997, <0.01). The rate of in the strong biofilm-forming ability group was higher than that in the weak biofilm-forming ability group (=10.803, <0.01). Most clinical isolates of PA can form biofilm. Swimming and twitching motilities are related to the formation of biofilm, but not significantly related to strength of biofilm-forming ability. The virulence genes of type Ⅲ secretion system for PA may be related to the biofilm-forming ability.}, } @article {pmid34402021, year = {2021}, author = {Caiaffa, KS and Dos Santos, VR and Abuna, GF and Santos-Filho, NA and Cilli, EM and Sakai, VT and Cintra, LTA and Duque, C}, title = {Cytocompatibility and Synergy of EGCG and Cationic Peptides Against Bacteria Related to Endodontic Infections, in Planktonic and Biofilm Conditions.}, journal = {Probiotics and antimicrobial proteins}, volume = {13}, number = {6}, pages = {1808-1819}, pmid = {34402021}, issn = {1867-1314}, mesh = {Actinomyces/drug effects ; *Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Catechin/*analogs & derivatives/pharmacology ; Enterococcus faecalis/drug effects ; Fusobacterium nucleatum/drug effects ; Peptides/*pharmacology ; Streptococcus mutans/drug effects ; }, abstract = {This study evaluated the cytocompatibility and antimicrobial/antibiofilm effects of epigallocatechin-3-gallate (EGCG) associated with peptide LL-37 and its analogue KR-12-a5 against oral pathogens. The effect of the compounds on metabolism of fibroblasts was evaluated by methyltetrazolium assays. Antimicrobial activity of the compounds was evaluated on Streptococcus mutans, Enterococcus faecalis, Actinomyces israelii, and Fusobacterium nucleatum under planktonic conditions, on single- and dual-species biofilms and E. faecalis biofilms in dentinal tubules and analyzed by bacterial counts and confocal microscopy. Data were statistically analyzed considering p < 0.05. EGCG and peptide combinations were not toxic to fibroblasts. KR-12-a5 showed synergistic or addictive effects with EGCG and LL-37 against all bacteria tested. However, EGCG associated with KR-12-a5 demonstrated the highest bactericidal activity on all bacteria tested, at lower concentrations. In single-species biofilms, EGCG + KR-12-a5 eliminated S. mutans and A. israelii and reduced E. faecalis and F. nucleatum counts around 5 log CFU/mL. EGCG + KR-12-a5 reduced E. faecalis (-3.93 log CFU/mL) and eliminated S. mutans in dual-species biofilms. No growth of E. faecalis and significant reduction in A. israelii (-6.24 log CFU/mL) and F. nucleatum (-4.62 log CFU/mL) counts were detected in dual-species biofilms. The combination of EGCG and KR-12-a5 led to 88% of E. faecalis dead cells inside dentin tubules. The association of EGCG and KR-12-a5 was cytocompatible and promoted synergistic effect against biofilms of bacteria associated with endodontic infections.}, } @article {pmid34399526, year = {2021}, author = {Savary, O and Mounier, J and Thierry, A and Poirier, E and Jourdren, J and Maillard, MB and Penland, M and Decamps, C and Coton, E and Coton, M}, title = {Tailor-made microbial consortium for Kombucha fermentation: Microbiota-induced biochemical changes and biofilm formation.}, journal = {Food research international (Ottawa, Ont.)}, volume = {147}, number = {}, pages = {110549}, doi = {10.1016/j.foodres.2021.110549}, pmid = {34399526}, issn = {1873-7145}, mesh = {Acetobacter ; Biofilms ; Brettanomyces ; Fermentation ; Hanseniaspora ; *Microbial Consortia ; *Microbiota ; }, abstract = {Kombucha is a very distinct naturally fermented sweetened tea that has been produced for thousands of years. Fermentation relies on metabolic activities of the complex autochthonous symbiotic microbiota embedded in a floating biofilm and used as a backslop for successive fermentations. Here, we designed a tailor-made microbial consortium representative of the core Kombucha microbiota to drive this fermentation. Microbial (counts, metagenetics), physico-chemical (pH, density) and biochemical (organic acids, volatile compounds) parameters were monitored as well as biofilm formation by confocal laser scanning microscopy and scanning electron microscopy. While nine species were co-inoculated, four (Dekkera bruxellensis, Hanseniaspora uvarum, Acetobacter okinawensis and Liquorilactobacillus nagelii) largely dominated. Microbial activities led to acetic, lactic, succinic and oxalic acids being produced right from the start of fermentation while gluconic and glucuronic acids progressively increased. A distinct shift in volatile profile was also observed with mainly aldehydes identified early on, then high abundances of fatty acids, ketones and esters at the end. Correlation analyses, combining metabolomic and microbial data also showed a shift in species abundances during fermentation. We also determined distinct bacteria-yeast co-occurence patterns in biofilms by microscopy. Our study provides clear evidence that a tailor-made consortium can be successfully used to drive Kombucha fermentations.}, } @article {pmid34399461, year = {2021}, author = {Nahar, S and Jeong, HL and Kim, Y and Ha, AJ and Roy, PK and Park, SH and Ashrafudoulla, M and Mizan, MFR and Ha, SD}, title = {Inhibitory effects of Flavourzyme on biofilm formation, quorum sensing, and virulence genes of foodborne pathogens Salmonella Typhimurium and Escherichia coli.}, journal = {Food research international (Ottawa, Ont.)}, volume = {147}, number = {}, pages = {110461}, doi = {10.1016/j.foodres.2021.110461}, pmid = {34399461}, issn = {1873-7145}, mesh = {Biofilms ; Endopeptidases ; Quorum Sensing ; *Salmonella typhimurium/genetics ; *Shiga-Toxigenic Escherichia coli/genetics ; Virulence/genetics ; }, abstract = {Salmonella enterica and Shiga toxin-producing (or verotoxin-producing) Escherichia coli are major foodborne pathogens, posing substantial food safety risks. Due to the negative effects of chemical treatment against foodborne pathogens, the application of enzyme-based techniques is currently receiving great attention. Here, we evaluated the inhibitory properties of Flavourzyme, a commercial peptidase, against these two foodborne pathogens. We noticed 4.0 and 5.5 log inhibition of biofilm formation by S. Typhimurium and E. coli, respectively, while treated with sub-minimum inhibitory concentrations of Flavourzyme for 24 h. For both bacteria, the enzyme exhibited quorum-quenching activity, preventing autoinducer-2 production completely by E. coli. In addition, Flavourzyme significantly suppressed the relative expression levels of biofilm-forming, quorum sensing, and virulence regulatory genes as measured by qRT-PCR. Based on our results, we suggest the use of Flavourzyme as a preventive agent against foodborne pathogens that possibly acts by inhibiting bacterial self-defense mechanisms following disruption of cellular proteins. This finding may shed light on how enzymes can be applied as a novel weapon to control foodborne illnesses to ensure food safety and public health.}, } @article {pmid34398504, year = {2021}, author = {Schooling, SR and Klinger, K and Korenevski, A and Glasauer, S}, title = {Reduction of antibiotic-induced biofilm accumulation of Pseudomonas aeruginosa by quaternized phytoglycogen.}, journal = {Letters in applied microbiology}, volume = {73}, number = {5}, pages = {544-552}, doi = {10.1111/lam.13554}, pmid = {34398504}, issn = {1472-765X}, support = {485333-15//NSERC/ ; 494633-16//NSERC/ ; //Mirexus Biotechnologies Inc/ ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; *Pseudomonas aeruginosa ; }, abstract = {Biofilms are oft cited as a factor in the unwanted persistence and recalcitrance of microbial life and a strong research initiative exists to identify, understand, and target vulnerabilities. Phytoglycogen is a biodegradable nanoparticulate biomaterial that is purified from crop plants. Importantly, the highly branched glucan structure provides a scaffold on which to construct novel polymers. Functionalized phytoglycogen (FP) was synthesized using green chemistry principles. Screening of several molecules identified a form of quaternized phytoglycogen which reduced biofilm formation and accretion by Pseudomonas aeruginosa. Exposing P. aeruginosa to modified phytoglycogen and antibiotic in combination not only substantively reduced biofilms, but also prevented increased biofilm formation, a biological response to suboptimal antibiotic concentrations. Treatment of pregrown biofilms with sub-minimum inhibitory concentration antibiotic alone also led to increased proliferation, whereas FP-antibiotic combinations prevented or reduced the extent of this. Swimming, swarming and twitching motility, all critical for biofilm development, were negatively affected by FP. This work supports phytoglycogen as a promising foundational molecule for novel polymers, including those with anti-biofilm function. Critically, in addition to published reports on how suboptimal antibiotic concentrations promote biofilm formation, we demonstrated a similar effect upon pre-existing biofilms, indicating a further route for the failure of antibiotic therapies.}, } @article {pmid34398099, year = {2021}, author = {Sen, CK and Roy, S and Mathew-Steiner, SS and Gordillo, GM}, title = {Biofilm Management in Wound Care.}, journal = {Plastic and reconstructive surgery}, volume = {148}, number = {2}, pages = {275e-288e}, pmid = {34398099}, issn = {1529-4242}, support = {R01 AI097511/AI/NIAID NIH HHS/United States ; R01 DK125835/DK/NIDDK NIH HHS/United States ; R01 NR013898/NR/NINR NIH HHS/United States ; R01 NR015676/NR/NINR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bacteria/*isolation & purification ; Biofilms/*drug effects ; Debridement/*methods ; Humans ; Treatment Outcome ; Wound Healing/drug effects ; Wound Infection/diagnosis/microbiology/*therapy ; }, abstract = {LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the basics of biofilm infection and be able to distinguish between planktonic and biofilm modes of growth. 2. Have a working knowledge of conventional and emerging antibiofilm therapies and their modes of action as they pertain to wound care. 3. Understand the challenges associated with testing and marketing antibiofilm strategies and the context within which these strategies may have effective value.

SUMMARY: The Centers for Disease Control and Prevention estimate for human infectious diseases caused by bacteria with a biofilm phenotype is 65 percent and the National Institutes of Health estimate is closer to 80 percent. Biofilms are hostile microbial aggregates because, within their polymeric matrix cocoons, they are protected from antimicrobial therapy and attack from host defenses. Biofilm-infected wounds, even when closed, show functional deficits such as deficient extracellular matrix and impaired barrier function, which are likely to cause wound recidivism. The management of invasive wound infection often includes systemic antimicrobial therapy in combination with débridement of wounds to a healthy tissue bed as determined by the surgeon who has no way of visualizing the biofilm. The exceedingly high incidence of false-negative cultures for bacteria in a biofilm state leads to missed diagnoses of wound infection. The use of topical and parenteral antimicrobial therapy without wound débridement have had limited impact on decreasing biofilm infection, which remains a major problem in wound care. Current claims to manage wound biofilm infection rest on limited early-stage data. In most cases, such data originate from limited experimental systems that lack host immune defense. In making decisions on the choice of commercial products to manage wound biofilm infection, it is important to critically appreciate the mechanism of action and significance of the relevant experimental system. In this work, the authors critically review different categories of antibiofilm products, with emphasis on their strengths and limitations as evident from the published literature.}, } @article {pmid34396989, year = {2021}, author = {Devaraj, A and Novotny, LA and Robledo-Avila, FH and Buzzo, JR and Mashburn-Warren, L and Jurcisek, JA and Tjokro, NO and Partida-Sanchez, S and Bakaletz, LO and Goodman, SD}, title = {The extracellular innate-immune effector HMGB1 limits pathogenic bacterial biofilm proliferation.}, journal = {The Journal of clinical investigation}, volume = {131}, number = {16}, pages = {}, pmid = {34396989}, issn = {1558-8238}, support = {R01 AI155501/AI/NIAID NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/immunology ; Biofilms/*growth & development ; Chinchilla ; DNA, Bacterial/immunology ; Extracellular Matrix/immunology ; Extracellular Traps/immunology ; Female ; HMGB1 Protein/*immunology ; Host Microbial Interactions/*immunology ; Humans ; Immunity, Innate ; Male ; Mice ; Mice, Inbred C57BL ; Models, Immunological ; Neutrophils/immunology ; }, abstract = {Herein, we describe an extracellular function of the vertebrate high-mobility group box 1 protein (HMGB1) in the proliferation of bacterial biofilms. Within host cells, HMGB1 functions as a DNA architectural protein, similar to the ubiquitous DNABII family of bacterial proteins; despite that, these proteins share no amino acid sequence identity. Extracellularly, HMGB1 induces a proinflammatory immune response, whereas the DNABII proteins stabilize the extracellular DNA-dependent matrix that maintains bacterial biofilms. We showed that when both proteins converged on extracellular DNA within bacterial biofilms, HMGB1, unlike the DNABII proteins, disrupted biofilms both in vitro (including the high-priority ESKAPEE pathogens) and in vivo in 2 distinct animal models, albeit with induction of a strong inflammatory response that we attenuated by a single engineered amino acid change. We propose a model where extracellular HMGB1 balances the degree of induced inflammation and biofilm containment without excessive release of biofilm-resident bacteria.}, } @article {pmid34396846, year = {2021}, author = {Vivier, B and Claquin, P and Lelong, C and Lesage, Q and Peccate, M and Hamel, B and Georges, M and Bourguiba, A and Sebaibi, N and Boutouil, M and Goux, D and Dauvin, JC and Orvain, F}, title = {Influence of infrastructure material composition and microtopography on marine biofilm growth and photobiology.}, journal = {Biofouling}, volume = {37}, number = {7}, pages = {740-756}, doi = {10.1080/08927014.2021.1959918}, pmid = {34396846}, issn = {1029-2454}, mesh = {Biofilms ; Biomass ; *Microalgae ; *Photobiology ; Photosynthesis ; }, abstract = {The impact of concrete composition and roughness on the formation of microalgal biofilms and their photobiology were studied on marine infrastructures presenting four different compositions combined with two degrees of roughness (rough and smooth). The structures were first inoculated with a natural microphytobenthic biofilm and immersed in sterilised seawater with a controlled photoperiod for six days. Photosynthetic activity was assessed with an imaging PAM-(Pulse Amplitude Modulated) fluorometer and microtopography was monitored in parallel with a 3-D camera. The results indicated that roughness had an impact on the biofilm biomass, its physiological status and its photosynthetic efficiency and capacity. The assessment of surface roughness indicated that negative reliefs were preferably colonised by MPB (microphytobenthic) cells with better photosynthetic performances. Moreover, MPB biofilms showed better photoacclimation in these microhabitats than on the positive and smooth reliefs. This study confirms the importance of microhabitat for biofilm formation and their photobiology.}, } @article {pmid34394043, year = {2021}, author = {Zhao, X and Lv, Y and Adam, FEA and Xie, Q and Wang, B and Bai, X and Wang, X and Shan, H and Wang, X and Liu, H and Dang, R and Wang, J and Yang, Z}, title = {Comparison of Antimicrobial Resistance, Virulence Genes, Phylogroups, and Biofilm Formation of Escherichia coli Isolated From Intensive Farming and Free-Range Sheep.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {699927}, pmid = {34394043}, issn = {1664-302X}, abstract = {Pathogenic E. coli are among the most frequently isolated bacterial pathogens on large-scale sheep farms in China. Antibiotic use in wool sheep production is a risk factor for promoting the emergence of resistant E. coli. To reveal the differences of E. coli populations in sheep from different farming systems the antimicrobial resistance, virulence genes, biofilm formation, and phylogroups of 500 E. coli isolates obtained between September 2019 and December 2020 in northwest China from diarrheic infections of intensive farming and free-range sheep were analyzed. The antimicrobial susceptibility test for 12 classes of antimicrobial agents was determined using the broth microdilution susceptibility method, and PCR was used to detect the differences in virulence genes and phylogroups. Additionally, biofilm formation was determined using microtiter plate and slide agglutination methods. Among the 500 E. coli isolates, the majority of the isolates were multidrug resistant (75.4%) and carried at least one virulence gene (94.8%). We observed that 412 (82.4%), 360 (72.0%), and 266 (53.2%) are found to be resistant to sulfisoxazole, florfenicol, and tetracyclines, respectively. Resistance was also observed to mequindox (46.8%), ampicillin (43.6%), spectinomycin (38.6%), enrofloxacin (34.2%), ceftiofur (21.0%), gentamycin (20.4%), ceftazidime (17.8%), and polymyxin B (7.8%) but no resistance was found to meropenem. These results showed that strains from free-range subjects had fewer antibiotic resistance strains rather than sheep that were intensively farmed (P < 0.05). We observed fifteen virulence genes, of which etrA (n = 401, 80.2%) is the most common. In addition, EAEC (86.4%) is dominant among free-range sheep and EHEC (80.1%) is dominant among intensive farming. Among all virulence genes, the strongest correlation was found between etrA and papC gene (P < 0.001, OR = 455.68). Similarly, the strongest correlation was also found between eltA and sulfisoxazole (P < 0.001, OR = 877). Furthermore, the majority of the E. coli isolates belonged to phylogroup B1 (50.6%), followed by phylogroup C (20.6%), A (7.4%), E (7.4%), D (5.8%), B2 (1.6%), and F (1%). Interestingly, phylogroup B2 and D were all distributed in intensive farms. In addition, 33 (6.6%), 373 (74.6%), and 94 (18.8%) showed moderate, weak, and no connection biofilm formation ability, respectively. These data uncovered that wool sheep serve as a reservoir of pathogenic E. coli harboring multiple resistance phenotypes and virulence genes. The overlapping virulence-associated traits between IPEC and ExPEC indicated the zoonotic potential and safety threats of sheep food products. It is urgent to improve the proper use of antimicrobials in China as well as other countries.}, } @article {pmid34392098, year = {2021}, author = {Song, C and Zhao, C and Wang, Q and Lu, S and She, Z and Zhao, Y and Jin, C and Guo, L and Li, K and Gao, M}, title = {Impact of carbon/nitrogen ratio on the performance and microbial community of sequencing batch biofilm reactor treating synthetic mariculture wastewater.}, journal = {Journal of environmental management}, volume = {298}, number = {}, pages = {113528}, doi = {10.1016/j.jenvman.2021.113528}, pmid = {34392098}, issn = {1095-8630}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Microbiota ; Nitrogen ; *Wastewater ; }, abstract = {The differences of cultured organism species, aquaculture model and supervisor mode lead to different carbon/nitrogen ratios in mariculture wastewater. Therefore, the performance, microbial community and enzymatic activity of sequencing batch biofilm reactor were compared in treating synthetic mariculture wastewater at different chemical oxygen demand/nitrogen (COD/N) ratios. Compared with COD/N ratio of 6, the ammonia-oxidizing rate and nitrite-oxidizing rate at COD/N ratio of 5, 4 and 3 increased by 3.66 % and 3.08 %, 11.19 % and 14.95 %, and 24.50 % and 32.54 %, respectively. Similarly, the ammonia monooxygenase and nitrite oxidoreductase activities increased by 3.50 % and 6.76 %, 11.09 % and 16.22 %, and 25.43 % and 39.19 % at COD/N ratio at 5, 4 and 3, respectively. However, the denitrifying rate and denitrification enzymatic activity declined with the decrease of C/N ratio from 6 to 3. The production, protein content and polysaccharide content of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) reduced with the decrease of COD/N ratio from 6 to 3. The abundance of nitrifying genera increased with the decrease of COD/N ratio from 6 to 3, whereas most of denitrification genera displayed a decreasing trend. The microbial co-occurrence pattern, keystone taxa and significant difference were altered with the decrease of COD/N ratio. Among the keystone taxa, Thauera, Denitromonas, Nitrosomonas and Denitratisoma had a close link with nitrogen transformation. The present results can provide some theoretical basis for evaluating the effect of carbon/nitrogen ratio on the nitrogen removal of biological wastewater treatment systems.}, } @article {pmid34391562, year = {2021}, author = {Zafar, MS and Ullah, R}, title = {PHENOLIC COMPOUND-DERIVED NATURAL ANTIMICROBIALS ARE LESS EFFECTIVE IN DENTAL BIOFILM CONTROL COMPARED TO CHLORHEXIDINE.}, journal = {The journal of evidence-based dental practice}, volume = {21}, number = {2}, pages = {101576}, doi = {10.1016/j.jebdp.2021.101576}, pmid = {34391562}, issn = {1532-3390}, mesh = {Adolescent ; *Anti-Infective Agents ; Biofilms ; Brazil ; Child ; *Chlorhexidine ; Humans ; Phenols ; }, abstract = {Efficacy of natural antimicrobials derived from phenolic compounds in the control of biofilm in children and adolescents compared to synthetic antimicrobials: A systematic review and meta-analysis. Martins ML, Ribeiro-Lages MB, Masterson D, Magno MB, Cavalcanti YW, Maia LC, Fonseca-Gonçalves A. Arch Oral Biol 2020;118:104844.

SOURCE OF FUNDING: Government. This study was financially supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Brazil (CAPES) through the grant number 001.

TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data.}, } @article {pmid34389439, year = {2021}, author = {Bonvicini, F and Belluti, F and Bisi, A and Gobbi, S and Manet, I and Gentilomi, GA}, title = {Improved eradication efficacy of a combination of newly identified antimicrobial agents in C. albicans and S. aureus mixed-species biofilm.}, journal = {Research in microbiology}, volume = {172}, number = {6}, pages = {103873}, doi = {10.1016/j.resmic.2021.103873}, pmid = {34389439}, issn = {1769-7123}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Chalcones/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Candida albicans and Staphylococcus aureus are common human pathogens, frequently isolated independently or co-isolated from bloodstream infections, and able to form dense polymicrobial biofilms on various medical devices resulting in strong resistance to conventionally used antimicrobials. New and innovative approaches are therefore needed to ensure the successful management of biofilm related infections. In this study, a chalcone-based derivative and a polycyclic anthracene-maleimide adduct, previously ascertained by us as inhibitors of C. albicans and S. aureus growths, respectively, were reconsidered in a new perspective by evaluating the efficacy of a combined treatment against a polymicrobial biofilm. Both quantitative and qualitative analyses were carried out to delve into their inhibitory potential on the polymicrobial population. Our results indicate that these newly identified antimicrobials are effective in reducing the biomass of the mixed C. albicans-S. aureus biofilm and the viability of fungal-bacterial cells within the polymicrobial community; in addition, confocal laser scanning microscopy demonstrates that the combined treatment thoroughly modifies the architecture of the dual-species biofilm.}, } @article {pmid34389392, year = {2021}, author = {Pandian, M and Selvaprithviraj, V and Pradeep, A and Rangasamy, J}, title = {In-situ silver nanoparticles incorporated N, O-carboxymethyl chitosan based adhesive, self-healing, conductive, antibacterial and anti-biofilm hydrogel.}, journal = {International journal of biological macromolecules}, volume = {188}, number = {}, pages = {501-511}, doi = {10.1016/j.ijbiomac.2021.08.040}, pmid = {34389392}, issn = {1879-0003}, mesh = {Adhesives/chemical synthesis/*chemistry ; Anti-Bacterial Agents/chemical synthesis/chemistry ; Chitosan/*chemistry ; Hydrogels/chemical synthesis/*chemistry ; Nanoparticles/*chemistry ; Silver/chemistry ; }, abstract = {Hydrogels are excellent wound healing materials. However, due to the wear and tear at the wound site, hydrogels can lose their structural and functional integrity. To overcome this and to effectively seal the wound and control infection, an in-situ silver nanoparticles (AgNps) incorporated N, O-carboxymethyl chitosan (N, O-CMC) based self-healing hydrogel using ethylenediaminetetraacetic acid-ferric ion (EDTA: Fe[3+]) complex was developed. The prepared N, O-CMC/AgNps hydrogel was characterized using FTIR, SEM, and TEM. The developed N, O-CMC/AgNps hydrogel was found to be adhesive, injectable, conductive, bio-compatible, and showed antibacterial activity against ATCC and clinical strains of E. coli, K. pneumonia, P. aeruginosa, S. aureus and MRSA. N, O-CMC/AgNps hydrogel also showed anti-biofilm activity against S. aureus, E. coli, and P. aeruginosa (ATCC strains). This developed antibacterial and self-healing N, O-CMC/AgNps hydrogel can be used in the treatment of infected wounds.}, } @article {pmid34388918, year = {2022}, author = {Luo, X and Zhang, B and Lu, Y and Mei, Y and Shen, L}, title = {Advances in application of ultraviolet irradiation for biofilm control in water and wastewater infrastructure.}, journal = {Journal of hazardous materials}, volume = {421}, number = {}, pages = {126682}, doi = {10.1016/j.jhazmat.2021.126682}, pmid = {34388918}, issn = {1873-3336}, mesh = {Biofilms ; Disinfection ; Prospective Studies ; *Ultraviolet Rays ; Wastewater ; Water ; *Water Purification ; }, abstract = {Biofilms are ubiquitous in aquatic environment. While so far, most of the ultraviolet (UV) disinfection studies focus on planktonic bacteria, and only limited attention has been given to UV irradiation on biofilms. To enrich this knowledge, the present paper reviews the up-to-date studies about applying UV to control biofilms in water and wastewater infrastructure. The development of UV light sources from the conventional mercury lamp to the light emitting diode (LED), and the resistance mechanisms of biofilms to UV are summarized, respectively. Then the feasibility to control biofilms with UV is discussed in terms of three technical routes: causing biofilm slough, inhibiting biofilm formation, and inactivating bacteria in the established biofilm. A comprehensive evaluation of the biofilm-targeted UV technologies currently used or potentially useful in water industry is provided as well, after comparative analyses on single/combined wavelengths, continuous/pulsed irradiation, and instant/chronic disinfection effects. UV LEDs are emerging as competitive light sources because of advantages such as possible selection of wavelengths, adjustable emitting mode and the designable configuration. They still, however, face challenges arising from the low wall plug efficiency and power output. At last, the implementation of the UV-based advanced oxidation processes in controlling biofilms on artificial surfaces is overviewed and their synergistic mechanisms are proposed, which further enlightens the prospective of UV in dealing with the biofilm issue in water infrastructure.}, } @article {pmid34388660, year = {2021}, author = {Zhang, Z and Zhao, Y and Yang, J and Guo, J and Li, J}, title = {Talaromyces cellulolyticus as a promising candidate for biofilm construction and treatment of textile wastewater.}, journal = {Bioresource technology}, volume = {340}, number = {}, pages = {125718}, doi = {10.1016/j.biortech.2021.125718}, pmid = {34388660}, issn = {1873-2976}, mesh = {Biofilms ; *Talaromyces ; Textile Industry ; Textiles ; Wastewater ; }, abstract = {Screening of microorganisms with broad-spectrum adaptability to extreme acid-base conditions and highperformance is essential for the construction of high-efficient biochemical wastewater treatment system. Herein, an acid-tolerant fungus isolated from acid medium was successfully identified through micromorphological observation and molecular characterization. The isolated fungus matched well with the filamentous fungus and was eventually identified as Talaromyces cellulolyticus. Considering the wide-range adaptability to pH condition (2.0-9.0), high cellulase activity (11.25 U mL[-1]), ideal biofilm-forming property (17.87 mg cm[-3]) on the surface of ceramsites, high tolerance to metal ions, and potential adsorption performance for aniline dyes, T. cellulolyticus issuitable for the construction of biofilm treatment system and treatment of textile wastewater based on the investigation of the removal efficiency of chemical oxygen demand and chromaticity of the synthetic textile wastewater. A promising candidate filamentous fungus for the treatment of textile wastewater was provided.}, } @article {pmid34388603, year = {2021}, author = {Wang, D and Kijkla, P and Mohamed, ME and Saleh, MA and Kumseranee, S and Punpruk, S and Gu, T}, title = {Aggressive corrosion of carbon steel by Desulfovibrio ferrophilus IS5 biofilm was further accelerated by riboflavin.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {142}, number = {}, pages = {107920}, doi = {10.1016/j.bioelechem.2021.107920}, pmid = {34388603}, issn = {1878-562X}, mesh = {Biofilms/*growth & development ; Corrosion ; Desulfovibrio/*metabolism ; Electron Transport ; *Riboflavin/chemistry/metabolism ; Steel/chemistry ; }, abstract = {EET (extracellular electron transfer) is behind MIC (microbiologically influenced corrosion) of carbon steel by SRB (sulfate reducing bacteria). This work evaluated 20 ppm (w/w) riboflavin (an electron mediator) acceleration of C1018 carbon steel MIC by Desulfovibrio ferrophilus IS5 in enriched artificial seawater (EASW) after 7-d incubation in anaerobic vials at 28 °C. Twenty ppm riboflavin did not significantly change cell growth or alter the corrosion product varieties, but it led to 52% increase in weight loss and 105% increase in pit depth, compared to the control without 20 ppm riboflavin. With 20 ppm riboflavin supplement in EASW, D. ferrophilus yielded weight loss-based corrosion rate of 1.57 mm/y (61.8 mpy), and pit depth growth rate of 2.88 mm/y (113 mpy), highest reported for short-term pure-strain SRB MIC of carbon steel. Electrochemical tests in 450 mL glass cells indicated that the biofilm responded rather quickly to the riboflavin injection (20 ppm in broth) to the culture medium. Polarization resistance (Rp) began to decrease within minutes after injection. Within 2 h, the riboflavin injection led to 31% decrease in Rp and 35% decrease in Rct + Rf from electrochemical impedance spectroscopy (EIS). The Tafel corrosion current density increased 63% 2 h after the injection.}, } @article {pmid34388130, year = {2021}, author = {Fu, W and Zhu, R and Lin, H and Zheng, Y and Hu, Z}, title = {Effect of organic concentration on biological activity and nitrogen removal performance in an anammox biofilm system.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {84}, number = {3}, pages = {725-736}, doi = {10.2166/wst.2021.258}, pmid = {34388130}, issn = {0273-1223}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Wastewater ; }, abstract = {The effects of different concentrations of organic matter on the biological activity and nitrogen removal performance of the anaerobic ammonium oxidation (anammox) system was studied. The results showed that under the conditions of low influent total organic carbon (TOC ≤ 100 mg/L), the activity rate of anammox bacteria was basically unaffected, the anammox bacteria and denitrifying bacteria formed a good synergistic effect, and the maximum total nitrogen (TN) removal efficiency reached 95.77%. However, when the influent TOC concentration was up to 200 mg/L, the activity of anammox bacteria was seriously inhibited. At this time, denitrification becomes the main pathway of nitrogen removal, the effluent ammonia nitrogen content increases, and the TN removal efficiency decreases to 64.17%. High-throughput sequencing analysis showed that with the increase in organic matter concentration, the relative abundance of Proteobacteria and Planctomycetes changed significantly. In particular, the relative abundance proportion of Proteobacteria increased from 21.06% to 25.57%, the Planctomycetes dropped from 10.01% to 3.03% and the Candidatus Brocadia genus had the largest decrease. In conclusion, the concentration range of organic matter for collaborative denitrification was proposed in this study, which provided theoretical reference for the practical application of anammox biofilm process.}, } @article {pmid34385992, year = {2021}, author = {Paes Leme, RC and da Silva, RB}, title = {Antimicrobial Activity of Non-steroidal Anti-inflammatory Drugs on Biofilm: Current Evidence and Potential for Drug Repurposing.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {707629}, pmid = {34385992}, issn = {1664-302X}, abstract = {It has been demonstrated that some non-steroidal anti-inflammatory drugs (NSAIDs), like acetylsalicylic acid, diclofenac, and ibuprofen, have anti-biofilm activity in concentrations found in human pharmacokinetic studies, which could fuel an interest in repurposing these well tolerated drugs as adjunctive therapies for biofilm-related infections. Here we sought to review the currently available data on the anti-biofilm activity of NSAIDs and its relevance in a clinical context. We performed a systematic literature review to identify the most commonly tested NSAIDs drugs in the last 5 years, the bacterial species that have demonstrated to be responsive to their actions, and the emergence of resistance to these molecules. We found that most studies investigating NSAIDs' activity against biofilms were in vitro, and frequently tested non-clinical bacterial isolates, which may not adequately represent the bacterial populations that cause clinically-relevant biofilm-related infections. Furthermore, studies concerning NSAIDs and antibiotic resistance are scarce, with divergent outcomes. Although the potential to use NSAIDs to control biofilm-related infections seems to be an exciting avenue, there is a paucity of studies that tested these drugs using appropriate in vivo models of biofilm infections or in controlled human clinical trials to support their repurposing as anti-biofilm agents.}, } @article {pmid34385452, year = {2021}, author = {Wang, Q and Vachon, J and Prasad, B and Pybus, CA and Lapin, N and Chopra, R and Greenberg, DE}, title = {Alternating magnetic fields and antibiotics eradicate biofilm on metal in a synergistic fashion.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {68}, pmid = {34385452}, issn = {2055-5008}, support = {R44 AI155291/AI/NIAID NIH HHS/United States ; S10 OD021684/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/drug effects/radiation effects ; Biofilms/*drug effects/*radiation effects ; Ciprofloxacin/pharmacology ; Drug Resistance, Bacterial ; Humans ; *Magnetic Fields ; *Metals ; Microbial Sensitivity Tests ; Prostheses and Implants/microbiology ; Pseudomonas aeruginosa/drug effects/radiation effects ; Staphylococcus aureus/drug effects/radiation effects ; }, abstract = {Hundreds of thousands of human implant procedures require surgical revision each year due to infection. Infections are difficult to treat with conventional antibiotics due to the formation of biofilm on the implant surface. We have developed a noninvasive method to eliminate biofilm on metal implants using heat generated by intermittent alternating magnetic fields (iAMF). Here, we demonstrate that heat and antibiotics are synergistic in biofilm elimination. For Pseudomonas aeruginosa biofilm, bacterial burden was reduced >3 log with iAMF and ciprofloxacin after 24 h compared with either treatment alone (p < 0.0001). This effect was not limited by pathogen or antibiotic as similar biofilm reductions were seen with iAMF and either linezolid or ceftriaxone in Staphylococcus aureus. iAMF and antibiotic efficacy was seen across various iAMF settings, including different iAMF target temperatures, dose durations, and dosing intervals. Initial mechanistic studies revealed membrane disruption as one factor important for AMF enhanced antibacterial activity in the biofilm setting. This study demonstrates the potential of utilizing a noninvasive approach to reduce biofilm off of metallic implants.}, } @article {pmid34384900, year = {2021}, author = {Karimaei, S and Kazem Aghamir, SM and Foroushani, AR and Pourmand, MR}, title = {Antibiotic tolerance in biofilm persister cells of Staphylococcus aureus and expression of toxin-antitoxin system genes.}, journal = {Microbial pathogenesis}, volume = {159}, number = {}, pages = {105126}, doi = {10.1016/j.micpath.2021.105126}, pmid = {34384900}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus/genetics ; *Toxin-Antitoxin Systems/genetics ; }, abstract = {The ability of Staphylococcus aureus to form biofilm and persister cells is the main cause of recurrent infections. This study aimed to evaluate the expression of toxin-antitoxin (TA) systems in persister cells within S. aureus biofilms. Time-dependent variation in the persister population present in biofilms of S. aureus was examined after treatment with bactericidal antibiotics. Then, the relative expression level of type II TA system (mazF, relE1, and relE2), type I TA system (sprG), and clpP protease genes in S. aureus strains were assessed by Real _Time PCR. Among the sixteen isolates, two isolates were found to be the strongest biofilm producers. The established biofilm of these isolates showed a comparable biphasic pattern at the lethal dose of the antibiotics. The expression level of TA system genes was increased and strain-specific expression patterns were observed under antibiotics stress conditions. Persisters within a biofilm may establish a reservoir for relapsing infection and could contribute to treatment failures. Hence, the possible role of the TA systems should be considered in biofilm and persister cell formation.}, } @article {pmid34383142, year = {2022}, author = {Buchbender, M and Fehlhofer, J and Proff, P and Möst, T and Ries, J and Hannig, M and Neurath, MF and Gund, M and Atreya, R and Kesting, M}, title = {Expression of inflammatory mediators in biofilm samples and clinical association in inflammatory bowel disease patients-a preliminary study.}, journal = {Clinical oral investigations}, volume = {26}, number = {2}, pages = {1217-1228}, pmid = {34383142}, issn = {1436-3771}, support = {DFG-SFB/TRR241//Deutsche Forschungsgesellschaft DFG/ ; }, mesh = {Biofilms ; *Colitis, Ulcerative ; *Crohn Disease ; Humans ; Inflammation Mediators ; *Inflammatory Bowel Diseases ; }, abstract = {OBJECTIVES: Inflammatory bowel disease (IBD) has multiple impacts on soft and hard tissues in the oral cavity. The aim of this study was to analyze the expression of cytokines in biofilm samples from patients suffering from IBD and compare them to healthy patients. It was hypothesized that different cytokine expression levels and clinical associations might be drawn.

MATERIAL AND METHODS: A total of 56 biofilm samples from three different patient cohorts (group 0 = healthy, HC n = 30; group 1 = Crohn's disease, CD, n = 19; group 2 = ulcerative colitis, UC, n = 7) were examined for the expression levels of the cytokine interleukins IL-2, -6, and -10; matrix metalloproteinases 7 and 9; and surface antigens CD90/CD11a by quantitative real-time PCR and according to clinical parameters (plaque index, BOP, PD, DMFT, CAL). Relative gene expression was determined using the ∆∆CT method.

RESULTS: The mean BOP values (p = 0.001) and PD (p = 0.000) were significantly higher in the CD group compared to controls. Expression of IL-10 was significantly higher in the CD (p = 0.004) and UC groups (p = 0.022). Expression of MMP-7 was significantly higher in the CD group (p = 0.032). IBD patients treated with TNF inhibitors (p = 0.007) or other immunosuppressants (p = 0.014) showed significant overexpression of IL-10 compared to controls.

CONCLUSION: Different expression levels of IL-10 and MMP-7 were detected in plaque samples from IBD patients. As only BOP was significantly increased, we conclude that no clinical impairment of periodontal tissue occurred in IBD patients.

CLINICAL RELEVANCE: With the worldwide increasing incidence of IBD, it is important to obtain insights into the effects of the disease on the oral cavity. The study was registered (01.09.2020) at the German clinical trial registry (DRKS00022956).

CLINICAL TRIAL REGISTRATION: The study is registered at the German clinical trial registry (DRKS00022956).}, } @article {pmid34381427, year = {2021}, author = {Miao, L and Wang, C and Adyel, TM and Zhao, J and Yan, N and Wu, J and Hou, J}, title = {Periphytic Biofilm Formation on Natural and Artificial Substrates: Comparison of Microbial Compositions, Interactions, and Functions.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {684903}, pmid = {34381427}, issn = {1664-302X}, abstract = {Periphytic biofilms have been widely used in wastewater purification and water ecological restoration, and artificial substrates have been progressively used for periphyton immobilisation to substitute natural substrates. However, there is insufficient knowledge regarding the interaction network structure and microbial functions in biofilm communities on artificial substrates, which are essential attribute affecting their applications in biofilm immobilisation. This study compared the community structure, co-occurrence network, and metabolic functions of bacterial and microeukaryotic periphytic biofilms during a 35-day indoor cultivation on artificial substrates, such as artificial carbon fibre (ACF) and polyvinyl chloride (PVC), and natural substrates, such as pebble and wood. Results demonstrated that different types of artificial substrates could affect the community composition and functional diversity of bacterial and microeukaryotic biofilms. The bacterial and microeukaryotic community on ACF and PVC showed significantly higher Simpson index compared to those on wood. Bacterial networks on artificial substrates were more complex than those on natural substrates, while the keystone species on natural substrates were more abundant, indicating that the bacterial communities on artificial substrates had stronger stability and resistance to external interference. Furthermore, the functional metabolic profiles predicted showed the abilities of bacterial communities to metabolise nitrogen and carbon sources colonised on artificial substrates were stronger than those on natural substrates. These findings demonstrated that artificial substrates could be special niches for microbial colonisation, possibly altering microbial compositions, interactions, and functions. Therefore, this study provides a powerful theoretical basis for choosing suitable artificial substrates for microbial aggregation and immobilisation technology.}, } @article {pmid34381318, year = {2021}, author = {Abualsaud, R and Aleraky, DM and Akhtar, S and Khan, SQ and Gad, MM}, title = {Antifungal Activity of Denture Base Resin Containing Nanozirconia: In Vitro Assessment of Candida albicans Biofilm.}, journal = {TheScientificWorldJournal}, volume = {2021}, number = {}, pages = {5556413}, pmid = {34381318}, issn = {1537-744X}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects ; Denture Bases/*microbiology ; Microscopy, Electron, Scanning ; Nanoparticles ; Resins, Synthetic ; Zirconium/administration & dosage/*pharmacology ; }, abstract = {OBJECTIVE: To evaluate the antimicrobial effects of different concentrations of zirconium dioxide nanoparticles (nano-ZrO2) reinforcement of poly(methyl) methacrylate (PMMA) on surface roughness and C. albicans biofilm.

METHODS: 20 heat-polymerized acrylic resin discs were conventionally made and divided into 4 groups (n = 5) according to nano-ZrO2 concentration: control (0% filler) and 3 experimental groups (2.5% (Z2.5), 5.0% (Z5.0), and 7.5% (Z7.5)). An optical profilometer was used for surface roughness evaluation, followed by Candida adherence assay. Specimens were sterilized, then immersed in cultured yeast (C. albicans), and incubated at 37°C for 48 hours. After that, discs were rinsed before extracting the clustered pellets of Candida. The attached C. albicans was counted using the direct method after spreading on agar media and incubating for 48 hours. Statistical analysis was performed using one-way ANOVA and Tukey's post hoc test at α = 0.05.

RESULTS: Surface roughness was significantly increased with all modified groups compared with control (P < 0.01), which showed the lowest roughness value (0.027 ± 0.004 μm). There was no significant difference in the roughness value among reinforced groups (2.5, 5.0, and 7.5%) (P > 0.05), with Z7.5 showing the highest roughness value (0.042 ± 0.004 μm). Candida count was reduced as the nano-ZrO2 increased but not significantly (P=0.15).

CONCLUSIONS: The addition of different concentrations of nano-ZrO2 particles to PMMA increased the surface roughness compared with control; in contrast, insignificant reduction of C. albicans biofilm was detected.}, } @article {pmid34380227, year = {2021}, author = {Liu, Z and Adyel, TM and Miao, L and You, G and Liu, S and Hou, J}, title = {Biofilm influenced metal accumulation onto plastic debris in different freshwaters.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {285}, number = {}, pages = {117646}, doi = {10.1016/j.envpol.2021.117646}, pmid = {34380227}, issn = {1873-6424}, mesh = {Biofilms ; Environmental Monitoring ; Lakes ; Metals ; *Plastics ; Rivers ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microbial biofilms can rapidly colonize plastic debris in aquatic environments and subsequently, accumulate chemical pollutants from the surrounding water. Here, we studied the microbial colonization of different plastics, including polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE) exposed in three freshwater systems (the Qinhuai River, the Niushoushan River, and Donghu Lake) for 44 days. We also assessed the biofilm mass and associated metals attached to plastics. The plastics debris characteristics, such as contact angle and surface roughness, greatly affected the increased biofilm biomass. All types of metal accumulation onto the plastic substrate abundances significantly higher than the concentrations of heavy metal in the water column, such as Ba (267.75 μg/g vs. 42.12 μg/L, Donhu Lake), Zn (254 μg/g vs. 0.023 μg/L the Qinhuai River), and Cr (93.75 μg/g vs. 0.039 μg/L, the Niushoushan River). Compared with other metals, the heavy metal Ba, Cr and Zn accumulated easily on the plastic debris (PET, PP, PVC, and PE) at all incubation sites. Aquatic environmental factors (total nitrogen, total phosphorus, and suspended solids concentrations) largely shaped metal accumulation onto plastic debris compared with plastic debris properties.}, } @article {pmid34379214, year = {2021}, author = {Ghasemi, M and Khorsandi, K and Kianmehr, Z}, title = {Photodynamic inactivation with curcumin and silver nanoparticles hinders Pseudomonas aeruginosa planktonic and biofilm formation: evaluation of glutathione peroxidase activity and ROS production.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {9}, pages = {149}, pmid = {34379214}, issn = {1573-0972}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects ; Cells, Cultured ; Curcumin/*pharmacology ; Drug Resistance, Multiple, Bacterial/drug effects ; Glutathione Peroxidase/*metabolism ; Humans ; Metal Nanoparticles ; Microbial Sensitivity Tests ; Particle Size ; Photochemotherapy/*methods ; Plankton/drug effects ; Pseudomonas aeruginosa/drug effects/*growth & development/metabolism ; Reactive Oxygen Species/*metabolism ; Silver/*pharmacology ; }, abstract = {Antibiotic-resistant bacteria result in high mortality in the world. Therefore, it is necessary to find new methods as alternative antibacterial agents that decline bacterial resistance and limit the spread of serious infectious bacterial diseases. Antimicrobial photodynamic therapy (aPDT) is a non-invasive strategy against antibiotic-resistant bacteria. aPDT contains the combination of non-toxic dyes with harmless visible light to create reactive oxygen species (ROS) that selectively lead to microbial cell death. Curcumin and silver nanoparticles (AgNPs) have antibacterial properties. In this study, the aPDT with curcumin plus AgNPs as photosensitizers on planktonic and biofilm forms of Pseudomonas aeruginosa was investigated. Also, the phototoxicity effect of curcumin and AgNPs on human fibroblast cells was studied. Finally, the ROS formation and the glutathione peroxidase (GPx) activity were evaluated. The results showed that the use of curcumin in combination with AgNPs then aPDT reduced the number of bacteria in planktonic and biofilm forms. Curcumin and AgNPs did not show any significant photocytotoxic effect against human normal fibroblast. Finally, the GPx activity was decreased in presence of curcumin in combination with AgNPs then aPDT compared to control. The ROS production in curcumin plus AgNPs then aPDT was higher than the control group. Therefore, curcumin-aPDT plus AgNPs could be suggested as novel strategies in treating multi-drug-resistant bacteria such as P. aeruginosa.}, } @article {pmid34378664, year = {2021}, author = {Haroon, M and Iqbal, MJ and Hassan, W and Ali, S and Ahmed, H and Hassan, SU}, title = {Evaluation of methanolic crude extract of Linum usitatissimum for the removal of biofilm in diabetic foot isolates.}, journal = {Brazilian journal of biology = Revista brasleira de biologia}, volume = {83}, number = {}, pages = {e245807}, doi = {10.1590/1519-6984.245807}, pmid = {34378664}, issn = {1678-4375}, mesh = {Biofilms ; *Diabetes Mellitus ; *Diabetic Foot/drug therapy ; *Flax ; Humans ; Methanol ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Staphylococcus aureus ; }, abstract = {Linum usitatissimum L is a widely used traditionally for multiple ailments. The present research was carried out to explore the antimicrobial, and anti-biofilm activity of crude extract of Linum usitatissimum L (Lu. Cr). Phytochemical and proximate analyses were performed. The bandages of diabetic foot patients were collected from the various hospitals. The bandages were cultured to isolate the bacterial strains present on it. The disc diffusion method was used to identify the antimicrobial potential whereas the minimum inhibitory concentration of the Lu.Cr were also determined. Proximate analysis confirms moisture content 8.33%, ash content 4.33%, crude protein 21.20%, crude fat 49.2% and crude fiber 5.63%. It was revealed that Gram-positive bacteria are most prevalent among all study groups. Lu.Cr possess significant bactericidal potential against S. aureus among all other microbes. Owing to this potential, linseed coated bandages can be used alternatively for the treatment of diabetic foot.}, } @article {pmid34378630, year = {2021}, author = {Dai, X and Ma, J and Zhang, Q and Xu, Q and Yang, L and Gao, F}, title = {Simultaneous inhibition of planktonic and biofilm bacteria by self-adapting semiconducting polymer dots.}, journal = {Journal of materials chemistry. B}, volume = {9}, number = {33}, pages = {6658-6667}, doi = {10.1039/d1tb01070k}, pmid = {34378630}, issn = {2050-7518}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biocompatible Materials/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Boronic Acids/chemistry/pharmacology ; HeLa Cells ; Humans ; Hydrogen-Ion Concentration ; Male ; Materials Testing ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Molecular Structure ; Naphthalimides/chemistry/pharmacology ; Particle Size ; Polymers/chemical synthesis/chemistry/*pharmacology ; Quantum Dots/chemistry ; Semiconductors ; Staphylococcal Infections/drug therapy/pathology ; Staphylococcus aureus/*drug effects/growth & development ; Surface Properties ; Tumor Cells, Cultured ; }, abstract = {Biofilm infections present an enormous challenge in today's healthcare settings. Currently, pH-switchable antibacterial agents are being developed to eradicate biofilms. However, most pH-switchable antibacterial agents are less lethal to planktonic bacteria under neutral conditions, and cannot prevent the dispersed bacteria from seeding acute infection again. Herein, this work reports the applications of semiconducting polymer dots (Pdots) with a double adhesion mechanism in imaging and inhibiting bacteria inside (weak acidic conditions) and outside (neutral conditions) biofilms. Clew-like Pdots were prepared by covalently linking phenylboronic acid (PBA) and pH-responsive naphthalimide (NA) ramification in semiconducting polymers. Under neutral conditions, the Pdots combined with bacteria through the formation of boronate esters between PBA and diols. Under weakly acidic conditions, the partial borate bond fractured, and the Pdots adhered onto the bacterial surface through the positively charged NA in Pdots. Furthermore, the Pdots display negligible toxicity to mammalian cells and tissues. More importantly, the Pdots can selectively damage the bacterial membrane and inhibit bacteria in vivo. This work highlights the feasibility of using semiconducting Pdots to image and inhibit bacteria inside and outside biofilms, which represents a highly effective strategy to cope with biofilm infections.}, } @article {pmid34377666, year = {2021}, author = {Fabre, S and Malik, Y and van De Guchte, A and Delgado-Noguera, LA and Gitman, MR and Nowak, MD and Sordillo, EM and Hernandez, MM and Paniz-Mondolfi, AE}, title = {Catheter-related bloodstream infection due to biofilm-producing Capnocytophaga sputigena.}, journal = {IDCases}, volume = {25}, number = {}, pages = {e01231}, pmid = {34377666}, issn = {2214-2509}, abstract = {Capnocytophaga sputigena is a facultatively-anaerobic bacterium that is part of the human oropharyngeal microflora. Although C. sputigena bacteremia is uncommon, systemic infections have been reported in both immunocompetent and immunocompromised patients. We report a case of catheter-related bloodstream infection by C. sputigena and highlight its enhanced biofilm-forming capacity in vitro.}, } @article {pmid34367616, year = {2021}, author = {Bachtiar, BM and Gani, BA and Deviana, A and Utami, NR and Andriyani, AD and Bachtiar, EW}, title = {The Discrepancy between Clove and Non-Clove Cigarette Smoke-Promoted Candida albicans Biofilm Formation with Precoating RNA-aptamer.}, journal = {F1000Research}, volume = {10}, number = {}, pages = {372}, pmid = {34367616}, issn = {2046-1402}, mesh = {*Aptamers, Nucleotide ; Biofilms ; Candida albicans/genetics ; Fungal Proteins/genetics ; RNA ; Smoking ; *Syzygium ; }, abstract = {This study explores the influence of precoating aptamer (Ca-apt1) on C. albicans viability while the fungus was growing in the presence of exposing condensed cigarette smoke (CSC), prepared from clove (CCSC) and non-clove (NCSC) cigarettes, for 48 h. Using qPCR, we found that mRNA expression of adhesion-associated genes (ALS3 and HWP1) was impaired by precoating C. albicans yeast cells with the aptamer. Conversely, the gene transcription was upregulated when aptamer-uncoated yeast was pre-treated with either CSC. In addition, by analysing the result of MTT ([3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay, we found that the presence of added CCSC or NCSC in growth medium for 48 h was significantly enhanced C. albicans biofilm development. However, the presence of precoated aptamer was significantly impaired biofilm development accelerated by the NCSC. The inhibitory effect of the Ca-apt1 was not dependent on the precoated aptamer (1ng/μL and 10 ng/μL). Interestingly, we noted that the enhancer effect of treated CCSC was no longer effective when the yeast had been precoated with 10 ng/μL aptamer tested. Additionally, light microscopy analysis revealed that precoating aptamer alleviates morphological changes of C. albicans (from yeast to hypha formation) that are enhanced by adding CCSC or NCSC in the growth medium. In conclusion, these results suggest that administration on Ca-ap1 exhibits a significant protective effect on CSC-induced biofilm formation by C. albicans.}, } @article {pmid34375931, year = {2021}, author = {Matjašič, T and Simčič, T and Kanduč, T and Samardžija, Z and Mori, N}, title = {Presence of polyethylene terephthalate (PET) fibers in hyporheic zone alters colonization patterns and seasonal dynamics of biofilm metabolic functioning.}, journal = {Water research}, volume = {203}, number = {}, pages = {117455}, doi = {10.1016/j.watres.2021.117455}, pmid = {34375931}, issn = {1879-2448}, mesh = {Biofilms ; Plastics ; *Polyethylene Terephthalates ; Rivers ; Seasons ; *Water Pollutants, Chemical/analysis ; }, abstract = {Worldwide, the production of plastics is increasing, and plastic pollution in aquatic environments is a major global concern. Under natural conditions, plastic weathers to smaller pieces called microplastics (MP), which come in various shapes, with fibers often being the most common in freshwater sediments. The hyporheic zone, an ecotone between surface and groundwater, is important for the transport and fate of all MP particles. The main metabolic pathways in rivers take place in the hyporheic zone and are driven by a diverse microbial community. The objective of this study was to investigate in situ whether the presence of PET fibers in riverbed sediments affects patterns of colonization and the seasonal dynamics of microbial metabolic activities in the hyporheic zone. The effects of the presence of PET on microbial metabolism were evaluated in situ over a month (colonization study) and over a year (seasonal study) by measuring total protein content (TPC), and microbial respiration as respiratory electron transport system activity (ETSA) and by community-level physiological profiling (CLPP). Additionally, PET fibers were examined under a scanning electron microscope (SEM), and isotopic analysis (δ[13]C) of PET was performed after one year of exposure to field conditions. The findings demonstrated that during colonization and biofilm formation, and also over the seasons, the date had a large and significant impact on biofilm growth and activity, while PET presence slightly suppressed microbial biomass (TPC) and respiratory activity (ETSA). Overall microbial activity was repressed in the presence of PET fibers but there was a higher capacity for the utilization of complex synthetic polymer substrates (i.e., Tween 40) which have previously been linked to polluted environments. SEM micrographs showed diverse microbial communities adhering to PET fibers but little surface deterioration. Similarly, isotopic analysis suggested little deterioration of PET fibers after one year of in situ conditions. The study indicated that PET fibers present in riverbed sediments could have impacts on the metabolic functioning in rivers and thus affect their self-cleaning ability.}, } @article {pmid34374560, year = {2021}, author = {McKloud, E and Delaney, C and Sherry, L and Kean, R and Williams, S and Metcalfe, R and Thomas, R and Richardson, R and Gerasimidis, K and Nile, CJ and Williams, C and Ramage, G}, title = {Recurrent Vulvovaginal Candidiasis: a Dynamic Interkingdom Biofilm Disease of Candida and Lactobacillus.}, journal = {mSystems}, volume = {6}, number = {4}, pages = {e0062221}, pmid = {34374560}, issn = {2379-5077}, support = {BB/P504567/1//UKRI | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; }, abstract = {Despite the strikingly high worldwide prevalence of vulvovaginal candidiasis (VVC), treatment options for recurrent VVC (RVVC) remain limited, with many women experiencing failed clinical treatment with frontline azoles. Further, the cause of onset and recurrence of disease is largely unknown, with few studies identifying potential mechanisms of treatment failure. This study aimed to assess a panel of clinical samples from healthy women and those with RVVC to investigate the influence of Candida, the vaginal microbiome, and how their interaction influences disease pathology. 16S rRNA sequencing characterized disease by a reduction in specific health-associated Lactobacillus species, such as Lactobacillus crispatus, coupled with an increase in Lactobacillus iners. In vitro analysis showed that Candida albicans clinical isolates are capable of heterogeneous biofilm formation, and we found the presence of hyphae and C. albicans aggregates in vaginal lavage fluid. Additionally, the ability of Lactobacillus to inhibit C. albicans biofilm formation and biofilm-related gene expression was demonstrated. Using RNA sequencing technology, we were able to identify a possible mechanism by which L. crispatus may contribute to re-establishing a healthy vaginal environment through amino acid acquisition from C. albicans. This study highlights the potential formation and impact of Candida biofilms in RVVC. Additionally, it suggests that RVVC is not entirely due to an arbitrary switch in C. albicans from commensal to pathogen and that understanding interactions between this yeast and vaginal Lactobacillus species may be crucial to elucidating the cause of RVVC and developing appropriate therapies. IMPORTANCE RVVC is a significant burden, both economically and for women's health, but its prevalence is poorly documented globally due to the levels of self-treatment. Identifying triggers for development and recurrence of VVC and the pathogenesis of the microbes involved could considerably improve prevention and treatment options for women with recurrent, azole-resistant cases. This study therefore aimed to examine the interkingdom dynamics from healthy women and those with RVVC using next-generation sequencing techniques and to further investigate the molecular interactions between C. albicans and L. crispatus in a relevant biofilm coculture system.}, } @article {pmid34374176, year = {2022}, author = {Aditya, V and Kotian, A and Saikrishnan, S and Rohit, A and Mithoor, D and Karunasagar, I and Deekshit, VK}, title = {Effect of ciprofloxacin and in vitro gut conditions on biofilm of Escherichia coli isolated from clinical and environmental sources.}, journal = {Journal of applied microbiology}, volume = {132}, number = {2}, pages = {964-977}, doi = {10.1111/jam.15249}, pmid = {34374176}, issn = {1365-2672}, support = {ECR/2017/00059//DST-SERB/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Ciprofloxacin/pharmacology ; Escherichia coli/genetics ; *Escherichia coli Infections/drug therapy ; Humans ; }, abstract = {AIM: This study aimed at characterizing the biofilm-forming ability of drug-resistant and sensitive Escherichia coli under in vitro gut conditions and in the presence of ciprofloxacin.

METHODS AND RESULTS: 153 E. coli isolates comprising 80 from clinical and 73 from environment source were studied for their ability to form biofilm under control and in vitro simulated gut conditions. The integrity of preformed biofilm on exposure to ciprofloxacin was assessed. Expression of biofilm-associated genes was analysed using qPCR. A high degree of resistance was observed in clinical isolates with a concomitant prevalence of blaTEM . Bile, pH and low temperature enabled the E. coli biofilm to resist the effect of ciprofloxacin. Clinical isolates of E. coli formed strong biofilms in in vitro gut conditions following exposure to high concentration of ciprofloxacin. The expression of biofilm genes varied between different gut conditions viz., presence of bile, pH and low temperature, included in this study.

CONCLUSIONS: This study demonstrates the importance of papC and csgA for maintaining the biofilm integrity upon antibiotic exposure. Escherichia coli form biofilm as a survival strategy to adapt to the conditions in their environment irrespective of their drug resistance status.

The study provides an understanding of the effect of different parameters of the gut conditions during infection and the effect of antibiotic on survival and biofilm-forming ability of clinical and environmental E. coli isolates. It further suggests that bacteria resort to biofilm formation as one of the mechanisms to adjust to alterations in gut conditions and once the biofilm is formed, it requires high concentration of ciprofloxacin to eradicate it.}, } @article {pmid34373534, year = {2021}, author = {Nguyen, H and Ybarra, A and Başağaoğlu, H and Shindell, O}, title = {Biofilm viscoelasticity and nutrient source location control biofilm growth rate, migration rate, and morphology in shear flow.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {16118}, pmid = {34373534}, issn = {2045-2322}, abstract = {We present a numerical model to simulate the growth and deformation of a viscoelastic biofilm in shear flow under different nutrient conditions. The mechanical interaction between the biofilm and the fluid is computed using the Immersed Boundary Method with viscoelastic parameters determined a priori from measurements reported in the literature. Biofilm growth occurs at the biofilm-fluid interface by a stochastic rule that depends on the local nutrient concentration. We compare the growth, migration, and morphology of viscoelastic biofilms with a common relaxation time of 18 min over the range of elastic moduli 10-1000 Pa in different nearby nutrient source configurations. Simulations with shear flow and an upstream or a downstream nutrient source indicate that soft biofilms grow more if nutrients are downstream and stiff biofilms grow more if nutrients are upstream. Also, soft biofilms migrate faster than stiff biofilms toward a downstream nutrient source, and although stiff biofilms migrate toward an upstream nutrient source, soft biofilms do not. Simulations without nutrients show that on the time scale of several hours, soft biofilms develop irregular structures at the biofilm-fluid interface, but stiff biofilms deform little. Our results agree with the biophysical principle that biofilms can adapt to their mechanical and chemical environment by modulating their viscoelastic properties. We also compare the behavior of a purely elastic biofilm to a viscoelastic biofilm with the same elastic modulus of 50 Pa. We find that the elastic biofilm underestimates growth rates and downstream migration rates if the nutrient source is downstream, and it overestimates growth rates and upstream migration rates if the nutrient source is upstream. Future modeling can use our comparison to identify errors that can occur by simulating biofilms as purely elastic structures.}, } @article {pmid34372023, year = {2021}, author = {Tambone, E and Marchetti, A and Ceresa, C and Piccoli, F and Anesi, A and Nollo, G and Caola, I and Bosetti, M and Fracchia, L and Ghensi, P and Tessarolo, F}, title = {Counter-Acting Candida albicans-Staphylococcus aureus Mixed Biofilm on Titanium Implants Using Microbial Biosurfactants.}, journal = {Polymers}, volume = {13}, number = {15}, pages = {}, pmid = {34372023}, issn = {2073-4360}, support = {Grant for young researchers involved in excellence research projects, ref. n 2017.0340//Fondazione Cassa di Risparmio di Trento e Rovereto/ ; Call PERIODONTOLOGY / IMPLANT DENTISTRY 2016.//SIdP (Italian Society of Periodontology and Implantology)/ ; Bando Fondazione CRT, Id. 393//Università degli Studi del Piemonte Orientale/ ; }, abstract = {This study aimed to grow a fungal-bacterial mixed biofilm on medical-grade titanium and assess the ability of the biosurfactant R89 (R89BS) coating to inhibit biofilm formation. Coated titanium discs (TDs) were obtained by physical absorption of R89BS. Candida albicans-Staphylococcus aureus biofilm on TDs was grown in Yeast Nitrogen Base, supplemented with dextrose and fetal bovine serum, renewing growth medium every 24 h and incubating at 37 °C under agitation. The anti-biofilm activity was evaluated by quantifying total biomass, microbial metabolic activity and microbial viability at 24, 48, and 72 h on coated and uncoated TDs. Scanning electron microscopy was used to evaluate biofilm architecture. R89BS cytotoxicity on human primary osteoblasts was assayed on solutions at concentrations from 0 to 200 μg/mL and using eluates from coated TDs. Mixed biofilm was significantly inhibited by R89BS coating, with similar effects on biofilm biomass, cell metabolic activity and cell viability. A biofilm inhibition >90% was observed at 24 h. A lower but significant inhibition was still present at 48 h of incubation. Viability tests on primary osteoblasts showed no cytotoxicity of coated TDs. R89BS coating was effective in reducing C. albicans-S. aureus mixed biofilm on titanium surfaces and is a promising strategy to prevent dental implants microbial colonization.}, } @article {pmid34371360, year = {2022}, author = {Maurya, A and Kumar, PS and Raj, A}, title = {Characterization of biofilm formation and reduction of hexavalent chromium by bacteria isolated from tannery sludge.}, journal = {Chemosphere}, volume = {286}, number = {Pt 2}, pages = {131795}, doi = {10.1016/j.chemosphere.2021.131795}, pmid = {34371360}, issn = {1879-1298}, mesh = {Alcaligenes ; Bacillus ; Bacteria ; Biodegradation, Environmental ; Biofilms ; Chromium/analysis ; Industrial Waste/analysis ; *Sewage ; *Water Pollutants, Chemical/analysis ; }, abstract = {Biofilm formation ability of bacteria makes them potential in the field of tannery effluent treatment. However, the hazardous nature of effluent and environmental conditions may disturb the biofilm formation ability of bacteria which ultimately affects their effluent treatment efficiency. Accordingly, we isolated and characterized biofilm-forming bacteria Bacillus vallismortis (MT027009), Bacillus haynesii (MT027008), and Alcaligenes aquatilis (MT027005) from tannery sludge and examined them for biofilm formation under variable environmental conditions. Biofilm formation in tryptic soy broth (TSB) at different incubation times (24-120 h) revealed that the biofilm formation activity of the strain B. haynesii was not affected by incubation time, whereas the increase in biofilm formation was observed in the case of B. vallismortis (28 %) and A. aquatilis (52 %) after 48 h. The medium pH (pH 5.0-9.0) had a limited effect on biofilm formation except in the case of A. aquatilis at pH 5.0 (94 %) and pH 9.0 (80 %). Furthermore, compared to the controls (only TSB), the strains B. vallismortis, B. haynesii, and A. aquatilis showed enhanced biofilm formation in undiluted tannery effluent (28, 33, and 21 %) and 25 mg L[-1] Cr(VI) (23 %, 48 % 32 %). The biofilm structure was influenced by Cr(VI) as revealed by scanning electron microscopy (SEM) analysis. The results of Cr(VI) bioreduction studies suggest that bacterial biofilm (60-99 %) has a greater potential to remove Cr(VI) than planktonic cells (43-94 %). The results of the study provide important data on biofilm formation by indigenous bacteria in effluent environment conditions, making them potential isolates for tannery effluent treatment.}, } @article {pmid34371086, year = {2021}, author = {Thorn, CR and Howell, PL and Wozniak, DJ and Prestidge, CA and Thomas, N}, title = {Enhancing the therapeutic use of biofilm-dispersing enzymes with smart drug delivery systems.}, journal = {Advanced drug delivery reviews}, volume = {179}, number = {}, pages = {113916}, doi = {10.1016/j.addr.2021.113916}, pmid = {34371086}, issn = {1872-8294}, support = {43998//CIHR/Canada ; 81361//CIHR/Canada ; FDN154327//CIHR/Canada ; }, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/*pharmacology ; Biofilms/*growth & development ; Drug Delivery Systems/*methods ; Drug Stability ; Enzymes/*administration & dosage/*pharmacology ; Extracellular Polymeric Substance Matrix/metabolism ; Humans ; }, abstract = {Biofilm-dispersing enzymes degrade the extracellular polymeric matrix surrounding bacterial biofilms, disperse the microbial community and increase their susceptibility to antibiotics and immune cells. Challenges for the clinical translation of biofilm-dispersing enzymes involve their susceptibility to denaturation, degradation, and clearance upon administration in vivo. Drug delivery systems aim to overcome these limitations through encapsulation, stabilization and protection from the exterior environment, thereby maintaining the enzymatic activity. Smart drug delivery systems offer target specificity, releasing payloads at the site of infection while minimizing unnecessary systemic exposure. This review highlights critical advances of biofilm-dispersing enzymes as a novel therapeutic approach for biofilm-associated infections. We explore how smart, bio-responsive delivery systems overcome the limiting factors of biofilm-dispersing enzymes and summarize the key systems designed. This review will guide future developments, focusing on utilizing selective and specific therapies in a targeted fashion to meet the unmet therapeutic needs of biofilm infections.}, } @article {pmid34368016, year = {2021}, author = {Vasicek, EM and O'Neal, L and Parsek, MR and Fitch, J and White, P and Gunn, JS}, title = {L-Arabinose Transport and Metabolism in Salmonella Influences Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {698146}, pmid = {34368016}, issn = {2235-2988}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI116917/AI/NIAID NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; R21 AI153752/AI/NIAID NIH HHS/United States ; }, mesh = {*Arabinose/metabolism ; *Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cyclic GMP ; Gene Expression Regulation, Bacterial ; Plasmids ; *Salmonella typhimurium/genetics/metabolism ; }, abstract = {L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation; therefore, L-arabinose metabolism could impact biofilm development. In this study we examined the impact of L-arabinose on Salmonella enterica serovar Typhimurium (S. Typhimurium) biofilm formation. Using mutants impaired for the transport and metabolism of L-arabinose, we showed that L-arabinose metabolism negatively impacts S. Typhimurium biofilm formation in vitro. When L-arabinose metabolism is abrogated, biofilm formation returned to baseline levels. However, without the ability to import extracellular L-arabinose, biofilm formation significantly increased. Using RNA-Seq we identified several gene families involved in these different phenotypes including curli expression, amino acid synthesis, and L-arabinose metabolism. Several individual candidate genes were tested for their involvement in the L-arabinose-mediated biofilm phenotypes, but most played no significant role. Interestingly, in the presence of L-arabinose the diguanylate cyclase gene adrA was downregulated in wild type S. Typhimurium. Meanwhile cyaA, encoding an adenylate cyclase, was downregulated in an L-arabinose transport mutant. Using an IPTG-inducible plasmid to deplete c-di-GMP via vieA expression, we were able to abolish the increased biofilm phenotype seen in the transport mutant. However, the mechanism by which the L-arabinose import mutant forms significantly larger biofilms remains to be determined. Regardless, these data suggest that L-arabinose metabolism influences intracellular c-di-GMP levels and therefore biofilm formation. These findings are important when considering the use of an L-arabinose inducible promoter in biofilm conditions.}, } @article {pmid34367868, year = {2021}, author = {Paul, P and Chakraborty, P and Sarker, RK and Chatterjee, A and Maiti, D and Das, A and Mandal, S and Bhattacharjee, S and Dastidar, DG and Tribedi, P}, title = {Tryptophan interferes with the quorum sensing and cell surface hydrophobicity of Staphylococcus aureus: a promising approach to inhibit the biofilm development.}, journal = {3 Biotech}, volume = {11}, number = {8}, pages = {376}, pmid = {34367868}, issn = {2190-572X}, abstract = {UNLABELLED: Staphylococcus aureus, a Gram-positive bacterium has been implicated in a plethora of human infections by virtue of its biofilm-forming ability. Inhibition in microbial biofilm formation has been found to be a promising approach towards compromising microbial pathogenesis. In this regard, various natural and synthetic molecules have been explored to attenuate microbial biofilm. In this study, the role of an amino acid, L-tryptophan was examined against the biofilm-forming ability of S. aureus. The compound did not execute any antimicrobial characteristics, instead, showed strong antibiofilm activity with the highest biofilm inhibition at a concentration of 50 µg/mL. Towards understanding the underlying mechanism of the same, efforts were given to examine whether tryptophan could inhibit biofilm formation by interfering with the quorum-sensing property of S. aureus. A molecular docking analysis revealed an efficient binding between the quorum-sensing protein, AgrA, and tryptophan. Moreover, the expression of the quorum-sensing gene (agrA) got significantly reduced under the influence of the test compound. These results indicated that tryptophan could interfere with the quorum-sensing property of the organism thereby inhibiting its biofilm formation. Further study revealed that tryptophan could also reduce the cell surface hydrophobicity of S. aureus by downregulating the expression of dltA. Moreover, the tested concentrations of tryptophan did not show any significant cytotoxicity. Hence, tryptophan could be recommended as a potential antibiofilm agent to manage the biofilm-associated infections caused by S. aureus.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02924-3.}, } @article {pmid34367134, year = {2021}, author = {Hetemäki, I and Jian, C and Laakso, S and Mäkitie, O and Pajari, AM and de Vos, WM and Arstila, TP and Salonen, A}, title = {Fecal Bacteria Implicated in Biofilm Production Are Enriched and Associate to Gastrointestinal Symptoms in Patients With APECED - A Pilot Study.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {668219}, pmid = {34367134}, issn = {1664-3224}, mesh = {Adult ; Aged ; Antibodies, Fungal/metabolism ; Bacteria/genetics/*growth & development/immunology/metabolism ; Biofilms/*growth & development ; Case-Control Studies ; Dysbiosis ; Feces/*microbiology ; Female ; Finland ; Gastrointestinal Diseases/diagnosis/immunology/metabolism/*microbiology ; *Gastrointestinal Microbiome ; Genetic Predisposition to Disease ; Host-Pathogen Interactions ; Humans ; Immunoglobulin G/metabolism ; Intestines/*microbiology ; Lipopolysaccharides/metabolism ; Male ; Metagenome ; Middle Aged ; *Mutation ; Pilot Projects ; Polyendocrinopathies, Autoimmune/complications/diagnosis/genetics/immunology ; Saccharomyces cerevisiae/genetics/immunology ; Transcription Factors/*genetics ; Young Adult ; }, abstract = {BACKGROUNDS AND AIMS: APECED is a rare autoimmune disease caused by mutations in the Autoimmune Regulator gene. A significant proportion of patients also have gastrointestinal symptoms, including malabsorption, chronic diarrhea, and obstipation. The pathological background of the gastrointestinal symptoms remains incompletely understood and involves multiple factors, with autoimmunity being the most common underlying cause. Patients with APECED have increased immune responses against gut commensals. Our objective was to evaluate whether the intestinal microbiota composition, predicted functions or fungal abundance differ between Finnish patients with APECED and healthy controls, and whether these associate to the patients' clinical phenotype and gastrointestinal symptoms.

METHODS: DNA was isolated from fecal samples from 15 patients with APECED (median age 46.4 years) together with 15 samples from body mass index matched healthy controls. DNA samples were subjected to analysis of the gut microbiota using 16S rRNA gene amplicon sequencing, imputed metagenomics using the PICRUSt2 algorithm, and quantitative PCR for fungi. Extensive correlations of the microbiota with patient characteristics were determined.

RESULTS: Analysis of gut microbiota indicated that both alpha- and beta-diversity were altered in patients with APECED compared to healthy controls. The fraction of Faecalibacterium was reduced in patients with APECED while that of Atopobium spp. and several gram-negative genera previously implicated in biofilm formation, e.g. Veillonella, Prevotella, Megasphaera and Heamophilus, were increased in parallel to lipopolysaccharide (LPS) synthesis in imputed metagenomics. The differences in gut microbiota were linked to patient characteristics, especially the presence of anti-Saccharomyces cerevisiae antibodies (ASCA) and severity of gastrointestinal symptoms.

CONCLUSIONS: Gut microbiota of patients with APECED is altered and enriched with predominantly gram-negative bacterial taxa that may promote biofilm formation and lead to increased exposure to LPS in the patients. The most pronounced alterations in the microbiota were associated with more severe gastrointestinal symptoms.}, } @article {pmid34367113, year = {2021}, author = {Zhou, T and Huang, J and Liu, Z and Xu, Z and Zhang, LH}, title = {Molecular Mechanisms Underlying the Regulation of Biofilm Formation and Swimming Motility by FleS/FleR in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {707711}, pmid = {34367113}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa, a major cause of nosocomial infection, can survive under diverse environmental conditions. Its great adaptive ability is dependent on its multiple signaling systems such as the two-component system (TCS). A TCS FleS/FleR has been previously identified to positively regulate a variety of virulence-related traits in P. aeruginosa PAO1 including motility and biofilm formation which are involved in the acute and chronic infections, respectively. However, the molecular mechanisms underlying these regulations are still unclear. In this study, we first analyzed the regulatory roles of each domains in FleS/FleR and characterized key residues in the FleS-HisKA, FleR-REC and FleR-AAA domains that are essential for the signaling. Next, we revealed that FleS/FleR regulates biofilm formation in a c-di-GMP and FleQ dependent manner. Lastly, we demonstrated that FleR can regulate flagellum biosynthesis independently without FleS, which explains the discrepant regulation of swimming motility by FleS and FleR.}, } @article {pmid34366603, year = {2022}, author = {Ding, M and Zhao, W and Song, LJ and Luan, SF}, title = {Stimuli-responsive nanocarriers for bacterial biofilm treatment.}, journal = {Rare metals}, volume = {41}, number = {2}, pages = {482-498}, pmid = {34366603}, issn = {1001-0521}, abstract = {ABSTRACT: Bacterial biofilm infections have been threatening the human's life and health globally for a long time because they typically cause chronic and persistent infections. Traditional antibiotic therapies can hardly eradicate biofilms in many cases, as biofilms always form a robust fortress for pathogens inside, inhibiting the penetration of drugs. To address the issues, many novel drug carriers emerged as promising strategies for biofilm treatment. Among them, stimuli-responsive nanocarriers have attracted much attentions for their intriguing physicochemical properties, such as tunable size, shape and surface chemistry, especially smart drug release characteristic. Based on the microenvironmental difference between biofilm infection sites and normal tissue, many stimuli, such as bacterial products accumulating in biofilms (enzymes, glutathione, etc.), lower pH and higher H2O2 levels, have been employed and proved in favor of "on-demand" drug release for biofilm elimination. Additionally, external stimuli including light, heat, microwave and magnetic fields are also able to control the drug releasing behavior artificially. In this review, we summarized recent advances in stimuli-responsive nanocarriers for combating biofilm infections, and mainly, focusing on the different stimuli that trigger the drug release.

摘要: , , 。 , , 。 , , 。 , -, , , , 。 , , (,), pHH2O2, ""。 , , , , 。 , , 。.}, } @article {pmid34365946, year = {2022}, author = {Chung, PYK and Gan, MY and Chin, BY}, title = {Pentacyclic Triterpenoids as Antibiofilm Agents against Methicillinresistant and Biofilm-forming Staphylococcus aureus (MRSA).}, journal = {Current pharmaceutical biotechnology}, volume = {23}, number = {6}, pages = {828-834}, doi = {10.2174/1389201022666210806092643}, pmid = {34365946}, issn = {1873-4316}, support = {BMS1/2018(7)//International Medical University (IMU), Malaysia/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections/microbiology ; Staphylococcus aureus ; *Triterpenes/chemistry/pharmacology ; }, abstract = {BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has been constantly evolv-ing and developing resistance against conventional antibiotics. One of the key features of MRSA that enables it to develop resistance to antibiotics and host immune system is its ability to form biofilm in indwelling medical devices. In previous studies, the antimicrobial activity and mechanisms of action of three known pentacyclic triterpenoids α-amyrin, betulinic acid and betulinaldehyde against planktonic cells of MRSA were determined and elucidated.

OBJECTIVE: This study was carried out to evaluate the ability of the three compounds to significantly reduce the biomass of pre-formed biofilms of MRSA and metabolic activity of the bacterial cells in the biofilm.

METHODS: The anti-biofilm activity of α-amyrin, betulinic acid and betulinaldehyde, individually and in combination with oxacillin or vancomycin, against reference strain of MRSA in pre-formed biofilm were evaluated using the crystal violet and resazurin assays.

RESULTS: α-amyrin and betulinic acid significantly reduced the biomass of pre-formed biofilms of MRSA as individual compounds and in combination with oxacillin or vancomycin. Although betulinaldehyde individually increased the biomass, selected combinations with oxacillin and vancomycin were able to reduce the biomass. All three compounds did not show cytotoxic properties on normal mammalian cells.

CONCLUSION: The three pentacyclic triterpenoids could significantly reduce pre-formed biofilm of MRSA with no cytotoxic effects on normal mammalian cells. These findings demonstrated that pentacyclic triterpenoids have the potential to be developed further as antibiofilm agents against MRSA cells in bio-films, to combat infections caused by multidrug-resistant and biofilm-forming S. aureus.}, } @article {pmid34361968, year = {2021}, author = {Qiao, J and Zheng, L and Lu, Z and Meng, F and Bie, X}, title = {Research on the Biofilm Formation of Staphylococcus aureus after Cold Stress.}, journal = {Microorganisms}, volume = {9}, number = {7}, pages = {}, pmid = {34361968}, issn = {2076-2607}, support = {2018YFC1602500//National Key R&D Program of China/ ; CX (18) 3053//Agricultural Science and Technology Innovation Fund in Jiangsu Province/ ; }, abstract = {Staphylococcus aureus is a common food pathogen and has a strong tolerance to environmental stress. Here, the biofilm formation of S. aureus strains after cold stress for 24 weeks were investigated. It was found that the biofilm formation of S. aureus CICC 21600, CICC 22942, W1, W3, and C1 cells was enhanced after cold stress for 20 weeks. What is more, the mRNA levels of the clfA, icaA, icaB, icaC or icaD genes in these strains were increased for >2-fold. The increased gene transcription levels were consistent with the increase in the polysaccharide content in the biofilm matrix of these S. aureus strains after cold stress. Meanwhile, hydrophobicity and the adhesion proteins also played a role in the formation of biofilms. The biofilm of S. aureus cells can be effectively degraded by snailase and proteinase K (125 µg/mL + 20 µg/mL) mixture. In summary, S. aureus frozen at -20 °C for 12 to 20 weeks is still a potential hazard. Food factory equipment should be cleaned in a timely manner to avoid outbreaks of foodborne pathogenic bacteria due to contamination.}, } @article {pmid34361928, year = {2021}, author = {Ottaviano, E and Baron, G and Fumagalli, L and Leite, J and Colombo, EA and Artasensi, A and Aldini, G and Borghi, E}, title = {Candida albicans Biofilm Inhibition by Two Vaccinium macrocarpon (Cranberry) Urinary Metabolites: 5-(3',4'-DihydroxyPhenyl)-γ-Valerolactone and 4-Hydroxybenzoic Acid.}, journal = {Microorganisms}, volume = {9}, number = {7}, pages = {}, pmid = {34361928}, issn = {2076-2607}, abstract = {Candida spp. are pathobionts, as they can switch from commensals to pathogens, responsible for a variety of pathological processes. Adhesion to surfaces, morphological switch and biofilm-forming ability are the recognized virulence factors promoting yeast virulence. Sessile lifestyle also favors fungal persistence and antifungal tolerance. In this study, we investigated, in vitro, the efficacy of two urinary cranberry metabolites, 5-(3',4'-dihydroxy phenyl)-γ-valerolactone (VAL) and 4-hydroxybenzoic acid (4-HBA), in inhibiting C. albicans adhesion and biofilm formation. Both the reference strain SC5314 and clinical isolates were used. We evaluated biomass reduction, by confocal microscopy and crystal violet assay, and the possible mechanisms mediating their inhibitory effects. Both VAL and 4-HBA were able to interfere with the yeast adhesion, by modulating the expression of key genes, HWP1 and ALS3. A significant dose-dependent reduction in biofilm biomass and metabolic activity was also recorded. Our data showed that the two cranberry metabolites VAL and 4-HBA could pave the way for drug development, for targeting the very early phases of biofilm formation and for preventing genitourinary Candida infections.}, } @article {pmid34361863, year = {2021}, author = {Al-Ahmad, A and Wollensak, K and Rau, S and Guevara Solarte, DL and Paschke, S and Lienkamp, K and Staszewski, O}, title = {How Do Polymer Coatings Affect the Growth and Bacterial Population of a Biofilm Formed by Total Human Salivary Bacteria?-A Study by 16S-RNA Sequencing.}, journal = {Microorganisms}, volume = {9}, number = {7}, pages = {}, pmid = {34361863}, issn = {2076-2607}, support = {03VP03860, BioSMAMPs (13XP5070)//German Federal Ministry of Science and Education (Bundesministerium für Bildung und Forschung)/ ; }, abstract = {Antimicrobial surface modifications are required to prevent biomaterial-associated biofilm infections, which are also a major concern for oral implants. The aim of this study was to evaluate the influence of three different coatings on the biofilm formed by human saliva. Biofilms grown from human saliva on three different bioactive poly(oxanorbornene)-based polymer coatings (the protein-repellent PSB: poly(oxanorbornene)-based poly(sulfobetaine), the protein-repellent and antimicrobial PZI: poly(carboxyzwitterion), and the mildly antimicrobial and protein-adhesive SMAMP: synthetic mimics of antimicrobial peptides) were analyzed and compared with the microbial composition of saliva, biofilms grown on uncoated substrates, and biofilms grown in the presence of chlorhexidine digluconate. It was found that the polymer coatings significantly reduced the amount of adherent bacteria and strongly altered the microbial composition, as analyzed by 16S RNA sequencing. This may hold relevance for maintaining oral health and the outcome of oral implants due to the existing synergism between the host and the oral microbiome. Especially the reduction of some bacterial species that are associated with poor oral health such as Tannerella forsythia and Fusobacterium nucleatum (observed for PSB and SMAMP), and Prevotella denticola (observed for all coatings) may positively modulate the oral biofilm, including in situ.}, } @article {pmid34361735, year = {2021}, author = {Trebino, MA and Shingare, RD and MacMillan, JB and Yildiz, FH}, title = {Strategies and Approaches for Discovery of Small Molecule Disruptors of Biofilm Physiology.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {15}, pages = {}, pmid = {34361735}, issn = {1420-3049}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R01AI102584/NH/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/biosynthesis/chemical synthesis/isolation & purification/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/chemistry/metabolism ; Biofilms/*drug effects/growth & development ; Cyclic GMP/antagonists & inhibitors/chemistry/metabolism ; Drug Design ; Drug Discovery ; Drug Resistance, Bacterial/drug effects ; Extracellular Polymeric Substance Matrix/chemistry/*drug effects/metabolism ; Gram-Negative Bacteria/*drug effects/growth & development/pathogenicity ; Gram-Positive Bacteria/*drug effects/growth & development/pathogenicity ; Lipids/antagonists & inhibitors/chemistry ; Microbial Sensitivity Tests ; Nucleic Acids/antagonists & inhibitors/chemistry/metabolism ; Polysaccharides, Bacterial/antagonists & inhibitors/chemistry/metabolism ; Small Molecule Libraries/chemistry/isolation & purification/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Biofilms, the predominant growth mode of microorganisms, pose a significant risk to human health. The protective biofilm matrix, typically composed of exopolysaccharides, proteins, nucleic acids, and lipids, combined with biofilm-grown bacteria's heterogenous physiology, leads to enhanced fitness and tolerance to traditional methods for treatment. There is a need to identify biofilm inhibitors using diverse approaches and targeting different stages of biofilm formation. This review discusses discovery strategies that successfully identified a wide range of inhibitors and the processes used to characterize their inhibition mechanism and further improvement. Additionally, we examine the structure-activity relationship (SAR) for some of these inhibitors to optimize inhibitor activity.}, } @article {pmid34361010, year = {2021}, author = {Bourigault, Y and Rodrigues, S and Crépin, A and Chane, A and Taupin, L and Bouteiller, M and Dupont, C and Merieau, A and Konto-Ghiorghi, Y and Boukerb, AM and Turner, M and Hamon, C and Dufour, A and Barbey, C and Latour, X}, title = {Biocontrol of Biofilm Formation: Jamming of Sessile-Associated Rhizobial Communication by Rhodococcal Quorum-Quenching.}, journal = {International journal of molecular sciences}, volume = {22}, number = {15}, pages = {}, pmid = {34361010}, issn = {1422-0067}, support = {//Ministère de l'Enseignement Supérieur, de la Recherche et de l'innovation/ ; //Régions Normandie, Bretagne and Pays de la Loire/ ; //Conseils Départementaux du Finistère et du Morbihan/ ; //Evreux Portes de Normandie agglomération/ ; //Quimper Communauté/ ; //Pôle de Compétivité Valorial/ ; //FEDER (European Union)/ ; }, mesh = {Acyl-Butyrolactones/metabolism ; Agrobacterium/genetics/metabolism/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Carboxylic Ester Hydrolases/genetics/metabolism ; *Quorum Sensing ; Rhodococcus/genetics/metabolism/*physiology ; }, abstract = {Biofilms are complex structures formed by a community of microbes adhering to a surface and/or to each other through the secretion of an adhesive and protective matrix. The establishment of these structures requires a coordination of action between microorganisms through powerful communication systems such as quorum-sensing. Therefore, auxiliary bacteria capable of interfering with these means of communication could be used to prevent biofilm formation and development. The phytopathogen Rhizobium rhizogenes, which causes hairy root disease and forms large biofilms in hydroponic crops, and the biocontrol agent Rhodococcus erythropolis R138 were used for this study. Changes in biofilm biovolume and structure, as well as interactions between rhizobia and rhodococci, were monitored by confocal laser scanning microscopy with appropriate fluorescent biosensors. We obtained direct visual evidence of an exchange of signals between rhizobia and the jamming of this communication by Rhodococcus within the biofilm. Signaling molecules were characterized as long chain (C14) N-acyl-homoserine lactones. The role of the Qsd quorum-quenching pathway in biofilm alteration was confirmed with an R. erythropolis mutant unable to produce the QsdA lactonase, and by expression of the qsdA gene in a heterologous host, Escherichia coli. Finally, Rhizobium biofilm formation was similarly inhibited by a purified extract of QsdA enzyme.}, } @article {pmid34360998, year = {2021}, author = {Chou, S and Li, Q and Wu, H and Li, J and Chang, YF and Shang, L and Li, J and Wang, Z and Shan, A}, title = {Selective Antifungal Activity and Fungal Biofilm Inhibition of Tryptophan Center Symmetrical Short Peptide.}, journal = {International journal of molecular sciences}, volume = {22}, number = {15}, pages = {}, pmid = {34360998}, issn = {1422-0067}, support = {CARS-35//China Agriculture Research System/ ; 31672434, 31872368, 31472104//National Natural Science Foundation of China/ ; TD2019C001//Natural Science Foundation of Heilongjiang Province/ ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Cardiolipins/metabolism ; Cell Membrane/drug effects ; Lipopolysaccharides/metabolism ; Oligopeptides/chemistry/*pharmacology ; Phosphatidylglycerols/metabolism ; Phosphatidylinositols/metabolism ; Phosphatidylserines/metabolism ; Teichoic Acids/metabolism ; Tryptophan/chemistry ; }, abstract = {Candida albicans, an opportunistic fungus, causes dental caries and contributes to mucosal bacterial dysbiosis leading to a second infection. Furthermore, C.albicans forms biofilms that are resistant to medicinal treatment. To make matters worse, antifungal resistance has spread (albeit slowly) in this species. Thus, it has been imperative to develop novel, antifungal drug compounds. Herein, a peptide was engineered with the sequence of RRFSFWFSFRR-NH2; this was named P19. This novel peptide has been observed to exert disruptive effects on fungal cell membrane physiology. Our results showed that P19 displayed high binding affinity to lipopolysaccharides (LPS), lipoteichoic acids (LTA) and the plasma membrane phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin, and phosphatidylglycerol (PG), further indicating that the molecular mechanism of P19 was not associated with the receptor recognition, but rather related to competitive interaction with the plasma membrane. In addition, compared with fluconazole and amphotericin B, P19 has been shown to have a lower potential for resistance selection than established antifungal agents.}, } @article {pmid34359522, year = {2021}, author = {Kimani, BG and Kerekes, EB and Szebenyi, C and Krisch, J and Vágvölgyi, C and Papp, T and Takó, M}, title = {In Vitro Activity of Selected Phenolic Compounds against Planktonic and Biofilm Cells of Food-Contaminating Yeasts.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34359522}, issn = {2304-8158}, support = {FK 134886//National Research, Development and Innovation Office/ ; EFOP-3.6.1-16-2016-00008//Hungarian Government and the European Union/ ; GINOP-2.3.2-15-2016-00012//Hungarian Government and the European Union/ ; ÚNKP-20-4-I//Ministry for Innovation and Technology/ ; K131796//National Research, Development and Innovation Office/ ; }, abstract = {Phenolic compounds are natural substances that can be obtained from plants. Many of them are potent growth inhibitors of foodborne pathogenic microorganisms, however, phenolic activities against spoilage yeasts are rarely studied. In this study, planktonic and biofilm growth, and the adhesion capacity of Pichia anomala, Saccharomyces cerevisiae, Schizosaccharomyces pombe and Debaryomyces hansenii spoilage yeasts were investigated in the presence of hydroxybenzoic acid, hydroxycinnamic acid, stilbene, flavonoid and phenolic aldehyde compounds. The results showed significant anti-yeast properties for many phenolics. Among the tested molecules, cinnamic acid and vanillin exhibited the highest antimicrobial activity with minimum inhibitory concentration (MIC) values from 500 µg/mL to 2 mg/mL. Quercetin, (-)-epicatechin, resveratrol, 4-hydroxybenzaldehyde, p-coumaric acid and ferulic acid were also efficient growth inhibitors for certain yeasts with a MIC of 2 mg/mL. The D. hansenii, P. anomala and S. pombe biofilms were the most sensitive to the phenolics, while the S. cerevisiae biofilm was quite resistant against the activity of the compounds. Fluorescence microscopy revealed disrupted biofilm matrix on glass surfaces in the presence of certain phenolics. Highest antiadhesion activity was registered for cinnamic acid with inhibition effects between 48% and 91%. The active phenolics can be natural interventions against food-contaminating yeasts in future preservative developments.}, } @article {pmid34358430, year = {2022}, author = {Roudbary, M and Vahedi-Shahandashti, R and Santos, ALSD and Roudbar Mohammadi, S and Aslani, P and Lass-Flörl, C and Rodrigues, CF}, title = {Biofilm formation in clinically relevant filamentous fungi: a therapeutic challenge.}, journal = {Critical reviews in microbiology}, volume = {48}, number = {2}, pages = {197-221}, doi = {10.1080/1040841X.2021.1950121}, pmid = {34358430}, issn = {1549-7828}, mesh = {*Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; *Fungi/genetics ; }, abstract = {Biofilms are highly-organized microbial communities attached to a biotic or an abiotic surface, surrounded by an extracellular matrix secreted by the biofilm-forming cells. The majority of fungal pathogens contribute to biofilm formation within tissues or biomedical devices, leading to serious and persistent infections. The clinical significance of biofilms relies on the increased resistance to conventional antifungal therapies and suppression of the host immune system, which leads to invasive and recurrent fungal infections. While different features of yeast biofilms are well-described in the literature, the structural and molecular basis of biofilm formation of clinically related filamentous fungi has not been fully addressed. This review aimed to address biofilm formation in clinically relevant filamentous fungi.}, } @article {pmid34358027, year = {2021}, author = {Skiba-Kurek, I and Nowak, P and Empel, J and Tomczak, M and Klepacka, J and Sowa-Sierant, I and Żak, I and Pomierny, B and Karczewska, E}, title = {Evaluation of Biofilm Formation and Prevalence of Multidrug-Resistant Strains of Staphylococcus epidermidis Isolated from Neonates with Sepsis in Southern Poland.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34358027}, issn = {2076-0817}, support = {2018/31/N/NZ6/03339//Narodowe Centrum Nauki/ ; N42/DBS/000164//Uniwersytet Jagielloński Collegium Medicum/ ; }, abstract = {Staphylococcus epidermidis strains play an important role in nosocomial infections, especially in the ones associated with biofilm formation on medical devices. The paper was aimed at analyzing the mechanisms of antibiotic resistance and confirming the biofilm-forming ability among S. epidermidis strains isolated from the blood of hospitalized newborns. Genetic analysis of resistance mechanism determinants included multiplex PCR detection of mecA, ermA, ermB, ermC, msrA, and mef genes. Biofilm analysis comprised phenotypic and genotypic methods including Christensen and Freeman methods and PCR detection of the icaADB gene complex. Among the tested S. epidermidis strains, 89% of the isolates were resistant to methicillin, 67%-to erythromycin, 53%-to clindamycin, 63%-to gentamicin, and 23%-to teicoplanin, while all the strains were susceptible to vancomycin and linezolid. The mecA gene was detected in 89% of the isolates, the ermC gene was the most common and present among 56% of the strains, while the msrA gene was observed in 11% isolates. Eighty-five percent of the strains were described as biofilm-positive by phenotypic methods and carried the icaADB gene cluster. Multidrug resistance and the biofilm-forming ability in most of the strains tested may contribute to antimicrobial therapy failure (p < 0.05).}, } @article {pmid34357732, year = {2021}, author = {Astashina, NB and Godovalov, AP and Rogozhnikova, EP and Tsareva, TV and Trefilova, YA and Grachev, DI and Arutyunov, AS}, title = {[Colonization activity of conditionally pathogenic microorganisms and features of biofilm formation on the surface of thermoplastic polymer material].}, journal = {Stomatologiia}, volume = {100}, number = {4}, pages = {72-76}, doi = {10.17116/stomat202110004172}, pmid = {34357732}, issn = {0039-1735}, mesh = {Biofilms ; Candida albicans ; Escherichia coli ; Humans ; *Polymers ; *Staphylococcus aureus ; }, abstract = {THE PURPOSE OF THE STUDY: Was to assess the microbial colonization and biofilm-forming activity of conditionally pathogenic microorganisms in vitro to samples of acrylic-free thermoplastic polymer material and to assess the possibility of its use for the manufacture of removable tooth splinting structures by injection method.

MATERIALS AND METHODS: The reference strains S. aureus, S. epidermidis, S. pyogenes, E. faecalis, E. coli, and C. albicans. Biofilm-forming activity was assessed by the level of ethanol extraction of a 0.1% aqueous solution of gentian violet by measuring on a PowerWave X microplate reader (USA).

RESULTS: A low degree of severity of microbial colonization and sufficient colonization resistance to the formation of a microbial biofilm of E. coli (0.374±0.056 cu opt. Pl.), S. aureus (0.272±0.039 cu. Opt. Pl.), S. epidermdis (0.299±0.028 cu opt. Pl.), S. ryogenes (0.399±0.069 cu opt. Pl.), E. faecalis (0.401±0.089 cu opt. Pl.). Moreover, C. albicans strains form a more pronounced biofilm (0.425±0.104 cu opt. Pl.) in comparison with other strains studied in the experiment.

CONCLUSION: Samples from a thermoplastic polymer based on polyoxymethylene have satisfactory biomedical characteristics and can be used at the stages of dental orthopedic treatment of patients without oral candidiasis.}, } @article {pmid34356953, year = {2021}, author = {Gómez-Casanova, N and Lozano-Cruz, T and Soliveri, J and Gomez, R and Ortega, P and Copa-Patiño, JL and Heredero-Bermejo, I}, title = {Eradication of Candida albicans Biofilm Viability: In Vitro Combination Therapy of Cationic Carbosilane Dendrons Derived from 4-Phenylbutyric Acid with AgNO3 and EDTA.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {7}, pages = {}, pmid = {34356953}, issn = {2309-608X}, support = {CTQ2017-86224-P//Ministerio de Economía, Industria y Competitividad, Gobierno de España/ ; B2017/BMD-3703//consortium NANODENDMED II-CM/ ; CCG19/CCS-022//Universidad de Alcalá/ ; CCG20CCS-013//Universidad de Alcalá/ ; CM/JIN/2019-020//Comunidad de Madrid/ ; }, abstract = {Candida albicans is a human pathogen of significant clinical relevance. This pathogen is resistant to different drugs, and most clinical antifungals are not effective against the prevention and treatment of C. albicans infections. As with other microorganisms, it can produce biofilms that serve as a barrier against antifungal agents and other substances, contributing to infection in humans and environmental tolerance of this microorganism. Thus, resistances and biofilm formation make treatment difficult. In addition, the complete eradication of biofilms in implants, catheters and other medical devices, is challenging and necessary to prevent relapses of candidemia. Therefore, it is a priority to find new molecules or combinations of compounds with anti-Candida biofilm activity. Due to the difficulty of treating and removing biofilms, the aim of this study was to evaluate the in vitro ability of different generation of cationic carbosilane dendrons derived from 4-phenylbutyric acid, ArCO2Gn(SNMe3I)m, to eradicate C. albicans biofilms. Here, we assessed the antifungal activity of the second generation dendron ArCO2G2(SNMe3I)4 against C. albicans cells and established biofilms since it managed to seriously damage the membrane. In addition, the combinations of the second generation dendron with AgNO3 or EDTA eradicated the viability of biofilm cells. Alterations were observed by scanning electron microscopy and cytotoxicity was assessed on HeLa cells. Our data suggest that the dendritic compound ArCO2G2(SNMe3I)4 could represent an alternative to control the infections caused by this pathogen.}, } @article {pmid34356930, year = {2021}, author = {Fasciana, T and Gargano, ML and Serra, N and Galia, E and Arrigo, I and Tricoli, MR and Diquattro, O and Graceffa, G and Vieni, S and Venturella, G and Giammanco, A}, title = {Potential Activity of Albino Grifola frondosa Mushroom Extract against Biofilm of Meticillin-Resistant Staphylococcus aureus.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {7}, pages = {}, pmid = {34356930}, issn = {2309-608X}, abstract = {Mushroom extracts are a rich source of natural compounds with antimicrobial properties, which are able to prevent, to some extent, the growth of foodborne pathogens. The aim of this study was to investigate the potential of extracts from albino Grifola frondosa (GF), commonly known as maitake, to inhibit the growth of some bacteria and the biofilm production by Staphylococcus aureus. We obtained not only a significant reduction of OD score between biofilm and biofilm plus albino G. frondosa extract group, but also a reduction of category of biofilm. In addition, we observed a significant presence of isolates with strong category for the biofilm group and a significant presence of isolates with absent category for the biofilm plus albino G. frondosa extract group. These results confirm that the use of albino G. frondosa extract reduces in significant way the presence of biofilm. Our results suggest and confirm that albino G. frondosa extracts could be employed as functional food and could be used as a natural additive for food process control and food safety.}, } @article {pmid34356800, year = {2021}, author = {de Oliveira, A and Pinheiro-Hubinger, L and Pereira, VC and Riboli, DFM and Martins, KB and Romero, LC and Cunha, MLRSD}, title = {Staphylococcal Biofilm on the Surface of Catheters: Electron Microscopy Evaluation of the Inhibition of Biofilm Growth by RNAIII Inhibiting Peptide.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34356800}, issn = {2079-6382}, support = {2011/07285-5//FAPESP/ ; 1/CX/CSRD VA/United States ; }, abstract = {Staphylococcus aureus and coagulase-negative staphylococci (CoNS) have become the main causative agents of medical device-related infections due to their biofilm-forming capability, which protects them from the host's immune system and from the action of antimicrobials. This study evaluated the ability of RNA III inhibiting peptide (RIP) to inhibit biofilm formation in 10 strains isolated from clinical materials, including one S. aureus strain, two S. epidermidis, two S. haemolyticus, two S. lugdunensis, and one isolate each of the following species: S. warneri, S. hominis, and S. saprophyticus. The isolates were selected from a total of 200 strains evaluated regarding phenotypic biofilm production and the presence and expression of the ica operon. The isolates were cultured in trypticase soy broth with 2% glucose in 96-well polystyrene plates containing catheter segments in the presence and absence of RIP. The catheter segments were observed by scanning electron microscopy. The results showed inhibition of biofilm formation in the presence of RIP in all CoNS isolates; however, RIP did not interfere with biofilm formation by S. aureus. RIP is a promising tool that might be used in the future for the prevention of biofilm-related infections caused by CoNS.}, } @article {pmid34356795, year = {2021}, author = {Bernardi, S and Anderson, A and Macchiarelli, G and Hellwig, E and Cieplik, F and Vach, K and Al-Ahmad, A}, title = {Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34356795}, issn = {2079-6382}, support = {AL 1179/4-1 and CI 263/3-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Enterococcus faecalis is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24-70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observed for a wide variety of bacterial pathogens and is associated with increased resistance. In this study, therefore, six E. faecalis isolates from an endodontic environment and two control strains were exposed to subinhibitory concentrations of Penicillin G, Amoxicillin, Doxycycline, Fosfomycin, Tetracycline and Vancomycin and examined for their biofilm formation abilities. The minimum inhibitory concentration (MIC) was determined for all E. faecalis isolates. A culture of the isolate was mixed with a serial dilution series of the respective antibiotic, incubated overnight and the biofilm formation was analyzed using a microtiter plate assay. All isolates were able to form biofilms in the absence of an antibiotic. A significant increase in biofilm formation of up to more than 50% was found in the isolates exposed to subinhibitory concentrations of various antibiotics. Most isolates showed a significant increase in Fosfomycin (7/8), Doxycycline (6/8) and Tetracycline (6/8). Three endodontic isolates showed a significant increase in five of the antibiotics examined at the same time. On exposure to Vancomycin, three endodontic isolates and the two control strains showed an increase. The increase in the ability to form biofilms extended over a concentration range from 1/2 to 1/64 of the MIC concentration. Antibiotics may reach certain niches in the oral cavity at subinhibitory concentrations only. This can increase the biofilm formation by enterococci, and in turn lead to decreased susceptibility of these taxa to antibiotics.}, } @article {pmid34356776, year = {2021}, author = {Koenig, HN and Durling, GM and Walsh, DJ and Livinghouse, T and Stewart, PS}, title = {Novel Nitro-Heteroaromatic Antimicrobial Agents for the Control and Eradication of Biofilm-Forming Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34356776}, issn = {2079-6382}, support = {GM116949/GM/NIGMS NIH HHS/United States ; }, abstract = {The synthesis and biological activity of several novel nitrothiazole, nitrobenzothiazole, and nitrofuran containing antimicrobial agents for the eradication of biofilm-forming Gram-negative and Gram-positive pathogens is described. Nitazoxanide (NTZ), nitrofurantoin, and furazolidone are commercial antimicrobials which were used as models to show how structural modification improved activity toward planktonic bacteria via minimum inhibitory concentration (MIC) assays and biofilms via minimum biofilm eradication concentration (MBEC) assays. Structure-activity relationship (SAR) studies illustrate the ways in which improvements have been made to the aforementioned antimicrobial agents. It is of particular interest in this regard that the introduction of a chloro substituent at the 5-position of NTZ (analog 1b) resulted in marked activity enhancement, as did the replacement of the 2-acetoxy substituent in the latter compound with a basic amine group (analog 7b). It is also of importance that analog 4a, which is a simple methacrylamide, displayed noteworthy activity against S. epidermidis biofilms. These lead compounds identified to have high activity towards biofilms provide promise as starting points in future pro-drug studies.}, } @article {pmid34354076, year = {2021}, author = {Monmeyran, A and Benyoussef, W and Thomen, P and Dahmane, N and Baliarda, A and Jules, M and Aymerich, S and Henry, N}, title = {Four species of bacteria deterministically assemble to form a stable biofilm in a millifluidic channel.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {64}, pmid = {34354076}, issn = {2055-5008}, mesh = {Bacillus thuringiensis ; Bacteria/*metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Biomass ; Kinetics ; *Microbial Interactions ; *Microbiota ; Micrococcaceae ; Pseudomonas fluorescens ; Rhodocyclaceae ; Species Specificity ; }, abstract = {Multispecies microbial adherent communities are widespread in nature and organisms, although the principles of their assembly and development remain unclear. Here, we test the possibility of establishing a simplified but relevant model of multispecies biofilm in a non-invasive laboratory setup for the real-time monitoring of community development. We demonstrate that the four chosen species (Bacillus thuringiensis, Pseudomonas fluorescens, Kocuria varians, and Rhodocyclus sp.) form a dynamic community that deterministically reaches its equilibrium after ~30 h of growth. We reveal the emergence of complexity in this simplified community as reported by an increase in spatial heterogeneity and non-monotonic developmental kinetics. Importantly, we find interspecies interactions consisting of competition for resources-particularly oxygen-and both direct and indirect physical interactions. The simplified experimental model opens new avenues to the study of adherent bacterial communities and their behavior in the context of rapid global change.}, } @article {pmid34352159, year = {2022}, author = {Sanghera, GK and Ingle, A}, title = {Unilateral refractory late periprosthetic breast implant seroma and biofilm.}, journal = {ANZ journal of surgery}, volume = {92}, number = {3}, pages = {592-594}, doi = {10.1111/ans.17106}, pmid = {34352159}, issn = {1445-2197}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; *Breast Neoplasms ; Female ; Humans ; *Mammaplasty ; Seroma/surgery/therapy ; }, } @article {pmid34351603, year = {2021}, author = {da Silva, PHR and de Assunção, EF and da Silva Velez, L and Dos Santos, LN and de Souza, EB and da Gama, MAS}, title = {Biofilm formation by strains of Burkholderia cenocepacia lineages IIIA and IIIB and B. gladioli pv. alliicola associated with onion bacterial scale rot.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {4}, pages = {1665-1675}, pmid = {34351603}, issn = {1678-4405}, support = {Process number 132864/2019-3//Brazilian National Research Council (CNPq)/ ; }, mesh = {*Biofilms ; Brazil ; *Burkholderia cenocepacia/classification/physiology/ultrastructure ; Microscopy, Electron, Scanning ; Onions/microbiology ; *Plant Diseases/microbiology ; }, abstract = {The Burkholderia genus has high ecological and nutritional versatility, having species capable of causing diseases in animals, humans, and plants. During chronic infections in humans, biofilm formation is a characteristic often associated with strains from different species of this genus. However, there is still no information on the formation of biofilms by plant pathogenic strains of B. cenocepacia (Bce) lineages IIIA and IIIB and B. gladioli pv. alliicola (Bga), which are associated with onion bacterial scale rot in the semi-arid region of northeast Brazil. In this study, we performed an in vitro characterization of biofilm formation ability in different culture media by the phytopathogenic strains of Bce and Bga and investigated its relationship with swarming motility. Our results indicated the existence of an intraspecific variation in biofilm formation capacity in vitro by these bacteria and the existence of a negative correlation between swarming motility and biofilm formation for strains of Bce lineage IIIB. In addition, histopathological analyses performed using optical microscopy and scanning electron microscopy revealed the formation of biofilm in vivo by Bce strains in onion tissues.}, } @article {pmid34351013, year = {2021}, author = {Parnell-Turner, H and Griffin, CE and Rosenkrantz, WS and Kelly Keating, M and Bidot, WA}, title = {Evaluation of the use of paired modified Wright's and periodic acid Schiff stains to identify microbial aggregates on cytological smears of dogs with microbial otitis externa and suspected biofilm.}, journal = {Veterinary dermatology}, volume = {32}, number = {5}, pages = {448-e122}, doi = {10.1111/vde.13009}, pmid = {34351013}, issn = {1365-3164}, mesh = {Animals ; Biofilms ; Coloring Agents ; Cross-Sectional Studies ; *Dog Diseases/diagnosis ; Dogs ; Extracellular Polymeric Substance Matrix ; *Otitis Externa/diagnosis/veterinary ; Periodic Acid ; Prospective Studies ; Reproducibility of Results ; }, abstract = {BACKGROUND: Micro-organisms associated with canine otitis externa (OE) may cause biofilm-associated infections (BAI). A key component of biofilm is microbial aggregate and extracellular polymeric substance (EPS). Periodic acid Schiff (PAS) can stain polysaccharide EPS in human otitis media with effusion, but this has not been tested in canine OE. There is no cytological definition for microbial aggregate, and definitive methods for identifying BAI in a clinical setting in canine OE have not been defined.

OBJECTIVES: To establish whether PAS stain can identify polysaccharide matrix on cytological smears; and to determine the reproducibility of identification of microbial aggregates within a discrete area of stained matrix, using paired modified Wright's and PAS-stained smears.

ANIMALS: Forty privately-owned dogs presenting to a dermatological referral practice.

METHODS AND MATERIALS: In this prospective, cross-sectional study, three investigators independently and blindly classified 40 paired modified Wright's-PAS slide sets into groups: aggregate-associated infection (AAI) and non-AAI (n = 27); and control (n = 13). Agreement between investigators for presence of AAI was measured using Fleiss' kappa statistic (FK). Agreement between investigators and dermatologists for presence of AAI upon cytological evaluation, and suspected BAI based on clinical examination, was measured using Cohen's kappa statistic.

RESULTS: The matrix was confirmed to stain PAS-positive. Interinvestigator agreement for AAI was very good using PAS (0.82 FK) and fair using modified-Wright's (MW) (0.33 FK). Reproducible cytological features associated with AAI were the presence of: three or more distinct aggregates (0.76 FK); discrete areas of PAS-positive matrix (0.70 FK); and the presence of high-density material (0.70 FK) using PAS stain.

CONCLUSION: PAS can stain the extracellular matrix on otic smears, and a novel protocol for reproducible identification of cytological features such as microbial aggregates has been established.}, } @article {pmid34350477, year = {2021}, author = {Gao, T and Li, Y and Chai, Y and Wang, Q and Ding, M}, title = {SigB regulates stress resistance, glucose starvation, MnSOD production, biofilm formation, and root colonization in Bacillus cereus 905.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {14-15}, pages = {5943-5957}, pmid = {34350477}, issn = {1432-0614}, support = {SXQN201902//Science Fund for Young Scholars from Beijing University of Agriculture/ ; KM202010020014//the Program of Science and Technology of Beijing Municipal Education Commission, China/ ; }, mesh = {*Bacillus cereus/genetics ; Bacterial Proteins/genetics ; Biofilms ; *Glucose ; Sigma Factor ; Superoxide Dismutase ; }, abstract = {Bacillus cereus 905, originally isolated from wheat rhizosphere, exhibits strong colonization ability on wheat roots. Our previous studies showed that root colonization is contributed by the ability of the bacterium to efficiently utilize carbon sources and form biofilms and that the sodA2 gene-encoded manganese-containing superoxide dismutase (MnSOD2) plays an indispensable role in the survival of B. cereus 905 in the wheat rhizosphere. In this investigation, we further demonstrated that the ability of B. cereus 905 to resist adverse environmental conditions is partially attributed to activation of the alternative sigma factor σ[B], encoded by the sigB gene. The sigB mutant experienced a dramatic reduction in survival when cells were exposed to ethanol, acid, heat, and oxidative stress or under glucose starvation. Analysis of the sodA2 gene transcription revealed a partial, σ[B]-dependent induction of the gene during glucose starvation or when treated with paraquat. In addition, the sigB mutant displayed a defect in biofilm formation under stress conditions. Finally, results from the root colonization assay indicated that sigB and sodA2 collectively contribute to B. cereus 905 colonization on wheat roots. Our study suggests a diverse role of SigB in rhizosphere survival and root colonization of B. cereus 905 under stress conditions. KEY POINTS : • SigB confers resistance to environmental stresses in B. cereus 905. • SigB plays a positive role in glucose utilization and biofilm formation in B. cereus. • SigB and SodA2 collectively contribute to colonization on wheat roots by B. cereus.}, } @article {pmid34349741, year = {2021}, author = {Hait, JM and Cao, G and Kastanis, G and Yin, L and Pettengill, JB and Tallent, SM}, title = {Evaluation of Virulence Determinants Using Whole-Genome Sequencing and Phenotypic Biofilm Analysis of Outbreak-Linked Staphylococcus aureus Isolates.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {687625}, pmid = {34349741}, issn = {1664-302X}, abstract = {Biofilms are a frequent cause of food contamination of potentially pathogenic bacteria, such as Staphylococcus aureus. Given its vast role in human disease, the possible impact of biofilm-producing S. aureus isolates in a food processing environment is evident. Sixty-nine S. aureus isolates collected from one firm following multiple staphylococcal food poisoning outbreak investigations were utilized for this analysis. Strain evaluations were performed to establish virulence determinants and the evolutionary relationships using data generated by shotgun whole-genome sequencing (WGS), along with end point polymerase chain reaction (PCR) and in vitro phenotypic assessments. S. aureus isolates were grouped into six well-supported clades in the phylogenetic tree, with the relationships within the clades indicating a strong degree of clonal structure. Our analysis identified four major sequence types 47.8% ST1, 31.9% ST45, 7.2% ST5, and 7.2% ST30 and two major spa types 47.8% t127 and 29.0% t3783. Extrapolated staphylococcal enterotoxin (SE) analysis found that all isolates were positive for at least 1 of the 23 SEs and/or SE-like toxin genes. Enterotoxigenic assessments found that 93% of the isolates expressed a classical SE(A-E). SE gene concurrence was observed at 96.2%, based on PCR and WGS results. In total, 46 gene targets were distinguished. This included genes that encode for adhesion and biofilm synthesis such as clfA, clfB, bbp, ebpS, ica, bap and agr. Our evaluation found agr group III to be the most prevalent at 55%, followed by 35% for agr group I. All isolates harbored the complete intercellular adhesion operon that is recognized to contain genes responsible for the adhesion step of biofilm formation by encoding proteins involved in the syntheses of the biofilm matrix. Phenotypic characterization of biofilm formation was evaluated three times, with each test completed in triplicate and accomplished utilizing the microtiter plate method and Congo red agar (CRA). The microtiter plate results indicated moderate to high biofilm formation for 96% of the isolates, with 4% exhibiting weak to no biofilm development. CRA results yielded all positive to intermediate results. The potential to inadvertently transfer pathogenic bacteria from the environment into food products creates challenges to any firm and may result in adulterated food.}, } @article {pmid34348276, year = {2021}, author = {Lu, Y and Zhang, H and Li, M and Mao, M and Song, J and Deng, Y and Lei, L and Yang, Y and Hu, T}, title = {The rnc Gene Regulates the Microstructure of Exopolysaccharide in the Biofilm of Streptococcus mutans through the β-Monosaccharides.}, journal = {Caries research}, volume = {55}, number = {5}, pages = {534-545}, doi = {10.1159/000518462}, pmid = {34348276}, issn = {1421-976X}, mesh = {Bacterial Adhesion ; Biofilms ; *Dental Caries ; Humans ; Monosaccharides ; *Streptococcus mutans/genetics ; }, abstract = {Streptococcus mutans is known as the crucial pathogen of human dental caries, owing to its contribution to the biofilm development via the capacity of synthesizing exopolysaccharide (EPS), which mainly compose of α-glycosidic bond and β-glycosidic bond. β-glycosidic bond is less flexible than α-glycosidic bond because of differences between their configurational properties. Previous studies have shown that the rnc gene is implicated in the EPS formation and the cariogenicity of S. mutans. However, the effects of rnc on the microstructure of EPS have been not well-understood yet. Here, we further investigated how the rnc gene worked to modulate microstructural properties of the extracellular polysaccharide of S. mutans using glycomics methods. The gas chromatography-mass spectrometer showed that the proportion of glucose was decreased in water-soluble EPS and galactose was absent in water-insoluble EPS from the S. mutans rnc-deficient strain (Smurnc), compared with the isogenic wild-type strain (UA159). The composition of functional groups and the displacement of hydrogen bond were analyzed by infrared radiation and 1H nuclear magnetic resonance, respectively. In addition, phenotypic modulation of the biofilm matrix was assessed by microscopy. We found that the EPS of UA159 and the rnc overexpression strain (Smurnc+) mainly consisted of β-glycosidic bonds. Conversely, the EPS of Smurnc were made up of mostly α-glycosidic bonds, leading to the attenuation of biofilm biomass and bacterial adhesion. Furthermore, the existence of β-glycosidic bond was verified by enzyme digestion. Collectively, the rnc gene modulates the conversion of β-glycosidic bonds, which may play important roles in regulating the micromolecule structure of the EPS matrix, thus affecting the characteristics of S. mutans biofilm. These data illustrate that β-glycosidic bonds mediated by rnc may be potential targets for the prevention and treatment of dental caries.}, } @article {pmid34346692, year = {2021}, author = {Xia, W and Li, N and Shan, H and Lin, Y and Yin, F and Yu, X and Zhou, Z}, title = {Gallium Porphyrin and Gallium Nitrate Reduce the High Vancomycin Tolerance of MRSA Biofilms by Promoting Extracellular DNA-Dependent Biofilm Dispersion.}, journal = {ACS infectious diseases}, volume = {7}, number = {8}, pages = {2565-2582}, doi = {10.1021/acsinfecdis.1c00280}, pmid = {34346692}, issn = {2373-8227}, mesh = {Biofilms ; DNA ; *Gallium/pharmacology ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; *Porphyrins ; Vancomycin/pharmacology ; }, abstract = {Biofilms, structured communities of bacterial cells embedded in a self-produced extracellular matrix (ECM) which consists of proteins, polysaccharide intercellular adhesins (PIAs), and extracellular DNA (eDNA), play a key role in clinical infections and are associated with an increased morbidity and mortality by protecting the embedded bacteria against drug and immune response. The high levels of antibiotic tolerance render classical antibiotic therapies impractical for biofilm-related infections. Thus, novel drugs and strategies are required to reduce biofilm tolerance and eliminate biofilm-protected bacteria. Here, we showed that gallium, an iron mimetic metal, can lead to nutritional iron starvation and act as dispersal agent triggering the reconstruction and dispersion of mature methicillin-resistant Staphylococcus aureus (MRSA) biofilms in an eDNA-dependent manner. The extracellular matrix, along with the integral bacteria themselves, establishes the integrated three-dimensional structure of the mature biofilm. The structures and compositions of gallium-treated mature biofilms differed from those of natural or antibiotic-survived mature biofilms but were similar to those of immature biofilms. Similar to immature biofilms, gallium-treated biofilms had lower levels of antibiotic tolerance, and our in vitro tests showed that treatment with gallium agents reduced the antibiotic tolerance of mature MRSA biofilms. Thus, the sequential administration of gallium agents (gallium porphyrin and gallium nitrate) and relatively low concentrations of vancomycin (16 mg/L) effectively eliminated mature MRSA biofilms and eradicated biofilm-enclosed bacteria within 1 week. Our results suggested that gallium agents may represent a potential treatment for refractory biofilm-related infections, such as prosthetic joint infections (PJI) and osteomyelitis, and provide a novel basis for future biofilm treatments based on the disruption of normal biofilm-development processes.}, } @article {pmid34346395, year = {2021}, author = {Dan, NH and Le Luu, T}, title = {Continuous flow sequencing bed biofilm reactor bio-digested landfill leachate treatment using electrocoagulation-persulfate.}, journal = {Journal of environmental management}, volume = {297}, number = {}, pages = {113409}, doi = {10.1016/j.jenvman.2021.113409}, pmid = {34346395}, issn = {1095-8630}, mesh = {Biofilms ; Electrocoagulation ; Electrodes ; Oxidation-Reduction ; *Water Pollutants, Chemical/analysis ; }, abstract = {Landfill leachate contains many complex components that have a negative impact on the environment when improperly discharged. This study is the first to treat landfill leachate (after continuous flow sequencing bed biofilm reactor (CF-SBBR) bio-digested) using electrocoagulation (EC) combined with persulfate (PS) on Al and Fe electrodes. The effect of some of the key parameters on the COD, Color, TOC and TN removal efficiencies as part of the EC-PS process were studied using the PS concentration, reaction time, initial pH, current density, and aeration rate. The results show that a PS concentration of 3 g/L improved the COD removal efficiency by 9.0 ± 1.3 % at the Al electrode and 16.0 ± 2.6 % at the Fe electrode. Aeration also improved the COD, TOC and color removal efficiencies by about 10.0 ± 2.3 %, 8.0 ± 1.7 % and 3.0 ± 0.5 % at an optimal aeration rate 3.3 L/min. The optimal operation conditions for the EC-PS process were a PS concentration of 3 g/L, a pH of 2.0 (Al electrode), a pH of 4.0 (Fe electrode), a reaction time of 70 min, a current density of 35 mA/cm[2] and an aeration rate of 3.3 L/min. The highest COD, color, TOC and TN removal efficiencies were 46.5 ± 1.8 %, 95.8 ± 2.4 %, 83.5 ± 1.7 %, and 40.9 ± 1.6 % at Al electrode and 54.4 ± 2.3 %, 98.5 ± 2.1 %, 78.6 ± 1.5 % and 57.9 ± 1.1 % at the Fe electrode. The EC-PS working mechanisms involve co-precipitation, an advanced oxidation process (AOPs) using oxidation radicals (HO, SO4[-]) and flotation. EC-PS is a promising method to treat bio-digested landfill leachate.}, } @article {pmid34344924, year = {2021}, author = {Tuck, B and Watkin, E and Forsyth, M and Somers, A and Ghorbani, M and Machuca, LL}, title = {Evaluation of a novel, multi-functional inhibitor compound for prevention of biofilm formation on carbon steel in marine environments.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {15697}, pmid = {34344924}, issn = {2045-2322}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Carbon ; Corrosion ; Microscopy, Confocal ; Molecular Structure ; *Seawater/microbiology ; *Steel/chemistry ; Surface Properties ; }, abstract = {Chemical biocides remain the most effective mitigation strategy against microbiologically influenced corrosion (MIC), one of the costliest and most pervasive forms of corrosion in industry. However, toxicity and environmental concerns associated with these compounds are encouraging the development of more environmentally friendly MIC inhibitors. In this study, we evaluated the antimicrobial effect of a novel, multi-functional organic corrosion inhibitor (OCI) compound, cetrimonium trans-4-hydroxy-cinnamate (CTA-4OHcinn). Attachment of three bacterial strains, Shewanella chilikensis, Pseudomonas balearica and Klebsiella pneumoniae was evaluated on wet-ground (120 grit finish) and pre-oxidised carbon steel surfaces (AISI 1030), in the presence and absence of the new OCI compound. Our study revealed that all strains preferentially attached to pre-oxidised surfaces as indicated by confocal laser scanning microscopy, scanning electron microscopy and standard colony forming unit (CFU) quantification assays. The inhibitor compound at 10 mM demonstrated 100% reduction in S. chilikensis attachment independent of initial surface condition, while the other two strains were reduced by at least 99.7% of the original viable cell number. Our results demonstrate that CTA-4OHcinn is biocidal active and has promise as a multifunctional, environmentally sound MIC inhibitor for industrial applications.}, } @article {pmid34344902, year = {2021}, author = {Blanco-Cabra, N and López-Martínez, MJ and Arévalo-Jaimes, BV and Martin-Gómez, MT and Samitier, J and Torrents, E}, title = {A new BiofilmChip device for testing biofilm formation and antibiotic susceptibility.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {62}, pmid = {34344902}, issn = {2055-5008}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/pharmacology ; Bacterial Infections/diagnosis/drug therapy ; Bacteriological Techniques/instrumentation/*methods ; Biofilms/*drug effects/*growth & development ; Delivery of Health Care ; Humans ; Laboratories, Clinical ; Microbial Sensitivity Tests ; Microfluidics ; Mycobacterium tuberculosis ; Pseudomonas aeruginosa ; Staphylococcus aureus ; }, abstract = {Currently, three major circumstances threaten the management of bacterial infections: increasing antimicrobial resistance, expansion of chronic biofilm-associated infections, and lack of an appropriate approach to treat them. To date, the development of accelerated drug susceptibility testing of biofilms and of new antibiofouling systems has not been achieved despite the availability of different methodologies. There is a need for easy-to-use methods of testing the antibiotic susceptibility of bacteria that form biofilms and for screening new possible antibiofilm strategies. Herein, we present a microfluidic platform with an integrated interdigitated sensor (BiofilmChip). This new device allows an irreversible and homogeneous attachment of bacterial cells of clinical origin, even directly from clinical specimens, and the biofilms grown can be monitored by confocal microscopy or electrical impedance spectroscopy. The device proved to be suitable to study polymicrobial communities, as well as to measure the effect of antimicrobials on biofilms without introducing disturbances due to manipulation, thus better mimicking real-life clinical situations. Our results demonstrate that BiofilmChip is a straightforward tool for antimicrobial biofilm susceptibility testing that could be easily implemented in routine clinical laboratories.}, } @article {pmid34343873, year = {2021}, author = {Wolff, D and Helmholz, L and Castronovo, S and Ghattas, AK and Ternes, TA and Wick, A}, title = {Micropollutant transformation and taxonomic composition in hybrid MBBR - A comparison of carrier-attached biofilm and suspended sludge.}, journal = {Water research}, volume = {202}, number = {}, pages = {117441}, doi = {10.1016/j.watres.2021.117441}, pmid = {34343873}, issn = {1879-2448}, mesh = {Biofilms ; Biomass ; Bioreactors ; Humans ; *Microbiota ; *Sewage ; Wastewater ; }, abstract = {The suspended sludge and carrier-attached biofilms of three different hybrid moving bed biofilm reactor (MBBR) systems were investigated with respect to their transformation potential for a broad range of micropollutants (MPs) as well as their microbial community composition. For this purpose, laboratory-scale batch experiments were conducted with the separated suspended sludge and the carrier-attached biofilm of every system in triplicate. For all batches the removal of 31 MPs as well as the composition of the microbial community were analyzed. The carrier-attached biofilms from two hybrid MBBR systems showed a significant higher overall transformation potential in comparison to the respective suspended sludge. Especially for the MPs trimethoprim, diclofenac, mecoprop, climbazole and the human metabolite 10,11-dihydro-10-hydroxycarbamazepine consistently higher pseudo-first-order transformation rates could be observed in all three systems. The analysis of the taxonomic composition revealed taxa showing higher relative abundances in the carrier-attached biofilms (e. g. Nitrospirae and Chloroflexi) and in the suspended biomasses (e. g. Bacteroidetes and Betaproteobacteria). Correlations of the biodiversity indices and the MP biotransformation rates resulted in significant positive associations for 11 compounds in suspended sludge, but mostly negative associations for the carrier-attached biofilms. The distinct differences in MP removal between suspended sludge and carrier-attached biofilm of the three different MBBR systems were also reflected by a statistically significant link between the occurrence of specific bacterial taxa (Acidibacter, Nitrospira and Rhizomicrobium) and MP transformation rates of certain MPs. Even though the identified correlations might not necessarily be of causal nature, some of the identified taxa might serve as suitable indicators for the transformation potential of suspended sludge or carrier-attached biofilms.}, } @article {pmid34343018, year = {2021}, author = {Serra, DO and Hengge, R}, title = {Bacterial Multicellularity: The Biology of Escherichia coli Building Large-Scale Biofilm Communities.}, journal = {Annual review of microbiology}, volume = {75}, number = {}, pages = {269-290}, doi = {10.1146/annurev-micro-031921-055801}, pmid = {34343018}, issn = {1545-3251}, mesh = {Bacteria ; Biofilms ; Biology ; *Escherichia coli/genetics ; *Escherichia coli Proteins ; Extracellular Matrix/chemistry ; }, abstract = {Biofilms are a widespread multicellular form of bacterial life. The spatial structure and emergent properties of these communities depend on a polymeric extracellular matrix architecture that is orders of magnitude larger than the cells that build it. Using as a model the wrinkly macrocolony biofilms of Escherichia coli, which contain amyloid curli fibers and phosphoethanolamine (pEtN)-modified cellulose as matrix components, we summarize here the structure, building, and function of this large-scale matrix architecture. Based on different sigma and other transcription factors as well as second messengers, the underlying regulatory network reflects the fundamental trade-off between growth and survival. It controls matrix production spatially in response to long-range chemical gradients, but it also generates distinct patterns of short-range matrix heterogeneity that are crucial for tissue-like elasticity and macroscopic morphogenesis. Overall, these biofilms confer protection and a potential for homeostasis, thereby reducing maintenance energy, which makes multicellularity an emergent property of life itself.}, } @article {pmid34341378, year = {2021}, author = {Munir, MT and Maneewan, N and Pichon, J and Gharbia, M and Oumarou-Mahamane, I and Baude, J and Thorin, C and Lepelletier, D and Le Pape, P and Eveillard, M and Irle, M and Pailhoriès, H and Aviat, F and Belloncle, C and Federighi, M and Dubreil, L}, title = {Confocal spectral microscopy, a non-destructive approach to follow contamination and biofilm formation of mCherry Staphylococcus aureus on solid surfaces.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {15574}, pmid = {34341378}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Fluorescence ; *Microscopy, Confocal ; Quercus/microbiology ; *Spectrum Analysis ; Staphylococcus aureus/*physiology ; Surface Properties ; Triazines ; Wood/microbiology ; }, abstract = {Methods to test the safety of wood material for hygienically sensitive places are indirect, destructive and limited to incomplete microbial recovery via swabbing, brushing and elution-based techniques. Therefore, we chose mCherry Staphylococcus aureus as a model bacterium for solid and porous surface contamination. Confocal spectral laser microscope (CSLM) was employed to characterize and use the autofluorescence of Sessile oak (Quercus petraea), Douglas fir (Pseudotsuga menziesii) and poplar (Populus euramericana alba L.) wood discs cut into transversal (RT) and tangential (LT) planes. The red fluorescent area occupied by bacteria was differentiated from that of wood, which represented the bacterial quantification, survival and bio-distribution on surfaces from one hour to one week after inoculation. More bacteria were present near the surface on LT face wood as compared to RT and they persisted throughout the study period. Furthermore, this innovative methodology identified that S. aureus formed a dense biofilm on melamine but not on oak wood in similar inoculation and growth conditions. Conclusively, the endogenous fluorescence of materials and the model bacterium permitted direct quantification of surface contamination by using CSLM and it is a promising tool for hygienic safety evaluation.}, } @article {pmid34340543, year = {2021}, author = {Silva-Rohwer, AR and Held, K and Sagawa, J and Fernandez, NL and Waters, CM and Vadyvaloo, V}, title = {CsrA Enhances Cyclic-di-GMP Biosynthesis and Yersinia pestis Biofilm Blockage of the Flea Foregut by Alleviating Hfq-Dependent Repression of the hmsT mRNA.}, journal = {mBio}, volume = {12}, number = {4}, pages = {e0135821}, pmid = {34340543}, issn = {2150-7511}, support = {R01 AI117016/AI/NIAID NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/biosynthesis ; Gastrointestinal Tract/*microbiology ; Host Factor 1 Protein/*genetics ; Host-Pathogen Interactions ; RNA, Messenger/*genetics/metabolism ; Siphonaptera/anatomy & histology/*microbiology ; Yersinia pestis/*metabolism/pathogenicity ; }, abstract = {Plague-causing Yersinia pestis is transmitted through regurgitation when it forms a biofilm-mediated blockage in the foregut of its flea vector. This biofilm is composed of an extracellular polysaccharide substance (EPS) produced when cyclic-di-GMP (c-di-GMP) levels are elevated. The Y. pestis diguanylate cyclase enzymes HmsD and HmsT synthesize c-di-GMP. HmsD is required for biofilm blockage formation but contributes minimally to in vitro biofilms. HmsT, however, is necessary for in vitro biofilms and contributes to intermediate rates of biofilm blockage. C-di-GMP synthesis is regulated at the transcriptional and posttranscriptional levels. In this, the global RNA chaperone, Hfq, posttranscriptionally represses hmsT mRNA translation. How c-di-GMP levels and biofilm blockage formation is modulated by nutritional stimuli encountered in the flea gut is unknown. Here, the RNA-binding regulator protein CsrA, which controls c-di-GMP-mediated biofilm formation and central carbon metabolism responses in many Gammaproteobacteria, was assessed for its role in Y. pestis biofilm formation. We determined that CsrA was required for markedly greater c-di-GMP and EPS levels when Y. pestis was cultivated on alternative sugars implicated in flea biofilm blockage metabolism. Our assays, composed of mobility shifts, quantification of mRNA translation, stability, and abundance, and epistasis analyses of a csrA hfq double mutant strain substantiated that CsrA represses hfq mRNA translation, thereby alleviating Hfq-dependent repression of hmsT mRNA translation. Additionally, a csrA mutant exhibited intermediately reduced biofilm blockage rates, resembling an hmsT mutant. Hence, we reveal CsrA-mediated control of c-di-GMP synthesis in Y. pestis as a tiered, posttranscriptional regulatory process that enhances biofilm blockage-mediated transmission from fleas. IMPORTANCE Yersinia pestis, the bacterial agent of bubonic plague, produces a c-di-GMP-dependent biofilm-mediated blockage of the flea vector foregut to facilitate its transmission by flea bite. However, the intricate molecular regulatory processes that underlie c-di-GMP-dependent biofilm formation and thus, biofilm-mediated blockage in response to the nutritional environment of the flea are largely undefined. This study provides a novel mechanistic understanding of how CsrA transduces alternative sugar metabolism cues to induce c-di-GMP-dependent biofilm formation required for efficient Y. pestis regurgitative transmission through biofilm-mediated flea foregut blockage. The Y. pestis-flea interaction represents a unique, biologically relevant, in vivo perspective on the role of CsrA in biofilm regulation.}, } @article {pmid34339991, year = {2022}, author = {Leiva-Aravena, E and Vera, MA and Nerenberg, R and Leiva, ED and Vargas, IT}, title = {Biofilm formation of Ancylobacter sp. TS-1 on different granular materials and its ability for chemolithoautotrophic As(III)-oxidation at high concentrations.}, journal = {Journal of hazardous materials}, volume = {421}, number = {}, pages = {126733}, doi = {10.1016/j.jhazmat.2021.126733}, pmid = {34339991}, issn = {1873-3336}, mesh = {*Arsenic ; Biofilms ; Oxidation-Reduction ; Silicates ; Titanium ; }, abstract = {The oxidation of arsenic (As) is a key step in its removal from water, and biological oxidation may provide a cost-effective and sustainable method. The biofilm-formation ability of Ancylobacter sp. TS-1, a novel chemolithoautotrophic As oxidizer, was studied for four materials: polypropylene, graphite, sand, and zeolite. After seven days under batch mixotrophic conditions, with high concentrations of As(III) (225 mg·L[-1]), biofilm formation was detected on all materials except for polypropylene. The results demonstrate As(III)-oxidation of TS-1 biofilms and suggest that the number of active cells was similar for graphite, sand, and zeolite. However, the biofilm biomass follows the specific surface area of each material: 7.0, 2.4, and 0.4 mg VSS·cm[-3] for zeolite, sand, and graphite, respectively. Therefore, the observed biofilm-biomass differences were probably associated with different amounts of EPS and inert biomass. Lastly, As(III)-oxidation kinetics were assessed for the biofilms formed on graphite and zeolite under chemolithoautotrophic conditions. The normalized oxidation rate for biofilms formed on these materials was 3.6 and 1.0 mg·L[-1]·h[-1]·cm[-3], resulting among the highest reported values for As(III)-oxidizing biofilms operated at high-As(III) concentrations. Our findings suggest that biofilm reactors based on Ancylobacter sp. TS-1 are highly promising for their utilization in As(III)-oxidation pre-treatment of high-As(III) polluted waters.}, } @article {pmid34339175, year = {2021}, author = {Rummel, CD and Lechtenfeld, OJ and Kallies, R and Benke, A and Herzsprung, P and Rynek, R and Wagner, S and Potthoff, A and Jahnke, A and Schmitt-Jansen, M}, title = {Conditioning Film and Early Biofilm Succession on Plastic Surfaces.}, journal = {Environmental science & technology}, volume = {55}, number = {16}, pages = {11006-11018}, doi = {10.1021/acs.est.0c07875}, pmid = {34339175}, issn = {1520-5851}, mesh = {Adsorption ; *Biofilms ; *Plastics ; Polymers ; Rivers ; }, abstract = {In the context of environmental plastic pollution, it is still under debate if and how the "plastisphere", a plastic-specific microbial community, emerges. In this study, we tested the hypothesis that the first conditioning film of dissolved organic matter (DOM) sorbs selectively to polymer substrates and that microbial attachment is governed in a substrate-dependent manner. We investigated the adsorption of stream water-derived DOM to polyethylene terephthalate (PET), polystyrene (PS), and glass (as control) including UV-weathered surfaces by Fourier-transform ion cyclotron mass spectrometry. Generally, the saturated, high-molecular mass and thus more hydrophobic fraction of the original stream water DOM preferentially adsorbed to the substrates. The UV-weathered polymers adsorbed more polar, hydrophilic OM as compared to the dark controls. The amplicon sequencing data of the initial microbial colonization process revealed a tendency of substrate specificity for biofilm attachment after 24 h and a clear convergence of the communities after 72 h of incubation. Conclusively, the adsorbed OM layer developed depending on the materials' surface properties and increased the water contact angles, indicating higher surface hydrophobicity as compared to pristine surfaces. This study improves our understanding of molecular and biological interactions at the polymer/water interface that are relevant to understand the ecological impact of plastic pollution on a community level.}, } @article {pmid34338626, year = {2021}, author = {Cardoso Guimarães, L and Marques de Souza, B and de Oliveira Whitaker, C and Abreu, F and Barreto Rocha Ferreira, R and Dos Santos, KRN}, title = {Increased biofilm formation by Staphylococcus aureus clinical isolates on surfaces covered with plasma proteins.}, journal = {Journal of medical microbiology}, volume = {70}, number = {8}, pages = {}, doi = {10.1099/jmm.0.001389}, pmid = {34338626}, issn = {1473-5644}, mesh = {Adhesins, Bacterial/genetics ; Bacterial Adhesion/genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; *Fibrinogen ; *Fibronectins ; Genes, Bacterial ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/genetics/isolation & purification/*pathogenicity/physiology ; Operon ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics/isolation & purification/*pathogenicity/physiology ; Trans-Activators/genetics ; }, abstract = {Introduction. Biofilm formation is a major virulence factor associated with Staphylococcus aureus infections. However, the influence of plasma proteins on biofilm formation of clinical isolates in vitro remains unclear.Hypotheses. We hypothesized that coating surfaces with plasma proteins might induce biofilm formation by S. aureus of different clonal lineages.Aim. To evaluate biofilm production by clinical S. aureus isolates of different clonal lineages isolated in Rio de Janeiro hospitals and investigated the presence of biofilm-associated genes.Methodology. This study assessed biofilm production of 60 S. aureus isolates in polystyrene microtitre plates with and without fibrinogen or fibronectin. The biochemical composition of the biofilm matrices was determined and the biofilm formation on fibrinogen-coated surfaces was also evaluated by confocal laser scanning microscopy. The presence of biofilm-related genes was detected by PCR, and the typing and functionality of agr operon was also evaluated.Results. Most of the isolates (45 %) were weak biofilm producers or non-producers. However, most of them presented a significant increase in biofilm production on plates covered with plasma proteins. There was no significant difference in biofilm formation between methicillin-resistant and -susceptible S. aureus isolates, or between different clonal lineages, except for ST30-IV (weak producers) and ST239-III (strong producers). The fnbB gene was associated with higher biofilm production.Conclusion. An increase in biofilm production in the presence of plasma proteins highlights the importance of investigating biofilm formation by S. aureus clinical isolates under different conditions since this virulence factor contributes to persistent infections and increased resistance to antimicrobials.}, } @article {pmid34337409, year = {2021}, author = {Ronco, T and Aragao, MF and Svenningsen, S and Christensen, JB and Permin, A and Saaby, L and Bionda, N and Lantz, EE and Olsen, RH}, title = {Efficacy of a novel antimicrobial hydrogel for eradication of Staphylococcus epidermidis, Staphylococcus aureus and Cutibacterium acnes from preformed biofilm and treatment performance in an in vivo MRSA wound model.}, journal = {JAC-antimicrobial resistance}, volume = {3}, number = {3}, pages = {dlab108}, pmid = {34337409}, issn = {2632-1823}, abstract = {BACKGROUND: Bacterial biofilm formation is a complicating factor in the antimicrobial treatment of bacterial infections.

OBJECTIVES: In this study, we assessed the impact of a novel hydrogel with the active antimicrobial compound JBC 1847 on eradication of preformed biofilms of Staphylococcus epidermidis, Cutibacterium acnes and MRSA in vitro, and evaluated the in vivo efficacy of MRSA wound treatment.

METHODS: Biofilms were exposed to JBC 1847 for 24 h and subsequently the treatments were neutralized and surviving biofilm-associated bacteria recovered and enumerated. The efficacy of the hydrogel on post-treatment load of MRSA was determined in a murine model of MRSA wound infection, and skin samples of the infected mice were examined histologically to evaluate the degree of healing.

RESULTS: A concentration-dependent eradication of biofilm-embedded bacteria by JBC 1847 was observed for all three pathogens, and the hydrogel caused a greater than four log reduction of cfu in all cases. In the mouse model, treatment with the hydrogel significantly reduced the cfu/mL of MRSA compared with treatment of MRSA-infected wounds with pure hydrogel. Histopathological analysis of the wounds showed that the JBC 1847 treatment group had a lower grade of inflammation, a higher mean score of re-epithelization and higher mean scores of parameters assessing the maturity of the newly formed epidermis, compared with both the fusidic acid 2% and vehicle treatment groups.

CONCLUSIONS: The novel hydrogel shows promising results as a candidate for future wound treatment, likely to be highly effective even in the case of biofilm-complicating infected wounds.}, } @article {pmid34335534, year = {2021}, author = {Li, C and Pan, D and Li, M and Wang, Y and Song, L and Yu, D and Zuo, Y and Wang, K and Liu, Y and Wei, Z and Lu, Z and Zhu, L and Shen, X}, title = {Aerobactin-Mediated Iron Acquisition Enhances Biofilm Formation, Oxidative Stress Resistance, and Virulence of Yersinia pseudotuberculosis.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {699913}, pmid = {34335534}, issn = {1664-302X}, abstract = {Aerobactin is a citrate-hydroxamate siderophore that is critical for the virulence of pathogenic enteric bacteria. However, although the aerobactin-producing iucABCD-iutA operon is distributed widely in the genomes of Yersinia species, none of the pathogenic Yersinia spp. was found to produce aerobactin. Here, we showed that the iucABCD-iutA operon in the food-borne enteric pathogen Yersinia pseudotuberculosis YPIII is a functional siderophore system involved in iron acquisition. The expression of the operon was found to be directly repressed by the ferric uptake regulator (Fur) in an iron concentration-dependent manner. In addition, we demonstrated that the aerobactin-mediated iron acquisition contributes to bacterial growth under iron-limited conditions. Moreover, we provided evidence that aerobactin plays important roles in biofilm formation, resistance to oxidative stress, ROS removal, and virulence of Y. pseudotuberculosis. Overall, our study not only uncovered a novel strategy of iron acquisition in Y. pseudotuberculosis but also highlighted the importance of aerobactin in the pathogenesis of Y. pseudotuberculosis.}, } @article {pmid34333420, year = {2021}, author = {Targhi, AA and Moammeri, A and Jamshidifar, E and Abbaspour, K and Sadeghi, S and Lamakani, L and Akbarzadeh, I}, title = {Synergistic effect of curcumin-Cu and curcumin-Ag nanoparticle loaded niosome: Enhanced antibacterial and anti-biofilm activities.}, journal = {Bioorganic chemistry}, volume = {115}, number = {}, pages = {105116}, doi = {10.1016/j.bioorg.2021.105116}, pmid = {34333420}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/*chemistry/metabolism/pharmacology ; Biofilms/drug effects ; Cell Line ; Cell Survival/drug effects ; Copper/*chemistry ; Curcumin/*chemistry/metabolism/pharmacology ; Drug Liberation ; Drug Synergism ; Humans ; Liposomes/*chemistry ; Metal Nanoparticles/*chemistry/toxicity ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/physiology ; Silver/*chemistry ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {In the current study, for the first time, the synergistic activity of curcumin and silver/copper nanoparticles (NPs) was studied against Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, a unique combination of curcumin and silver/copper NPs in free and encapsulated forms was prepared and delivered through a niosomal system. For this purpose, different niosomal formulations of curcumin and metal NPs were prepared by thin film hydration method. Then, the dual drug-loaded niosomes were dispersed in chitosan hydrogel in order to widen its applications. The effect of the molar ratios of lipid to drug and surfactant to cholesterol was investigated to find the optimized noisomal nanoparticles in terms of size, polydispersity index (PDI), and entrapment efficiency (EE). The size and PDI values were measured by dynamic light scattering (DLS). Morphology and in vitro drug release kinetics of niosomes were examined by scanning and transmission electron microscopy (SEM, TEM) and dialysis method, respectively. The drug-loaded niosomes and their hydrogel counterpart were screened for investigating their antibacterial activity against S. aureus and P. aeruginosa by disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Furthermore, anti-biofilm assay and expression of biofilm-associated genes by Real-time PCR were performed to evaluate the anti-biofilm effect of NPs. In this study, the drug-loaded niosomal formulations showed good entrapment efficiencies (EE) with a sustained release profile over 72 h. Moreover, compared to free drugs, the optimized niosomal formulations increased antibacterial activity against the bacteria via promotion in the inhibition zone and reduction in MIC and MBC values. Interestingly, gel-based niosomal formulations increased the inhibition zone by about 6 mm and significantly decreased MIC and MBC values compared to niosomal formulations. Also, biofilm eradication of curcumin-metal NPs encapsulated into niosomal hydrogel was highest compared to free and niosomal drugs. Overall, curcumin-Cu or curcumin-Ag nanoparticle loaded niosomes incorporated in hydrogel hold great promise for biomedical applications.}, } @article {pmid34333239, year = {2021}, author = {da Silva, RAG and Afonina, I and Kline, KA}, title = {Eradicating biofilm infections: an update on current and prospective approaches.}, journal = {Current opinion in microbiology}, volume = {63}, number = {}, pages = {117-125}, doi = {10.1016/j.mib.2021.07.001}, pmid = {34333239}, issn = {1879-0364}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; *Bacterial Infections/drug therapy ; Biofilms ; Humans ; Prospective Studies ; }, abstract = {Biofilm formation is a multifactorial process and often a multi-species endeavour that involves complex signalling networks, chemical gradients, bacterial adhesion, and production or acquisition of matrix components. Antibiotics remain the main choice when treating bacterial biofilm-associated infections despite their intrinsic tolerance to antimicrobials, and propensity for acquisition and rapid dissemination of antimicrobial resistance within the biofilm. Eliminating hard to treat biofilm-associated infections that are antibiotic resistant will demand a holistic and multi-faceted approach, targeting multiple stages of biofilm formation, many of which are already in development. This mini review will highlight the current approaches that are employed to treat bacterial biofilm infections and discuss new approaches in development that have promise to reach clinical practice.}, } @article {pmid34333135, year = {2021}, author = {Vieira, MS and Duarte da Silva, J and Ferro, CG and Cunha, PC and Vidigal, PMP and Canêdo da Silva, C and Oliveira de Paula, S and Dias, RS}, title = {A highly specific Serratia-infecting T7-like phage inhibits biofilm formation in two different genera of the Enterobacteriaceae family.}, journal = {Research in microbiology}, volume = {172}, number = {6}, pages = {103869}, doi = {10.1016/j.resmic.2021.103869}, pmid = {34333135}, issn = {1769-7123}, mesh = {Amino Acid Substitution ; Biofilms/*growth & development ; Escherichia coli/*growth & development ; Genome, Viral ; Host Specificity ; Hydrogen-Ion Concentration ; Microbial Interactions ; Podoviridae/classification/genetics/isolation & purification/*physiology ; Protein Domains ; Serratia liquefaciens/*growth & development ; Serratia marcescens/*growth & development/*virology ; Temperature ; Viral Tail Proteins/chemistry ; Virus Latency ; }, abstract = {Due to the emergence of multidrug-resistant bacteria, bacteriophages have become a viable alternative in controlling bacterial growth or biofilm formation. Biofilm is formed by extracellular polymeric substances (EPS) and is one of the factors responsible for increasing bacterial resistance. Bacteriophages have been studied as a bacterial control agent by use of phage enzymes or due to their bactericidal activities. A specific phage against Serratia marcescens was isolated in this work and was evaluated its biological and genomic aspects. The object of this study was UFV01, a bacteriophage belonging to the Podoviridae family, genus Teseptimavirus (group of lytic viruses), specific to the species S. marcescens, which may be related to several amino acid substitutions in the virus tail fibers. Despite this high specificity, the phage reduced the biofilm formation of several Escherichia coli strains without infecting them. UFV01 presents a relationship with phages of the genus Teseptimavirus, although it does not infect any of the E. coli strains evaluated, as these others do. All the characteristics make the phage an interesting alternative in biofilm control in hospital environments since small breaks in the biofilm matrix can lead to a complete collapse.}, } @article {pmid34332222, year = {2021}, author = {Ruhal, R and Kataria, R}, title = {Biofilm patterns in gram-positive and gram-negative bacteria.}, journal = {Microbiological research}, volume = {251}, number = {}, pages = {126829}, doi = {10.1016/j.micres.2021.126829}, pmid = {34332222}, issn = {1618-0623}, mesh = {*Biofilms ; *Gram-Negative Bacteria/physiology ; *Gram-Positive Bacteria/physiology ; }, abstract = {The Gram-positive and Gram-negative bacteria are attributable to matrix-enclosed aggregates known as biofilms. Biofilms are root cause of industrial biofouling and characterized by antimicrobial resistance during infections. Many biofilm studies examine specific Gram type cultures, whereas nearly all biofilm communities in nature comprise both Gram-negative and Gram-positive bacteria. Thus, a greater understanding of the conserved themes in biofilm formation is required for common therapeutics. We tried to focus on common components which exist at each stage of biofilm development and regulation. The Lipopolysaccharides (LPS) and cell wall glyco-polymers of Gram-negative and Gram-positive bacteria seem to play similar roles during initial adhesion. The inhibition of the polymerization of amyloid-like proteins might impact the biofilms of both Gram-type bacteria. Enzymatic degradation of matrix components by glycoside hydrolase and DNase (nuclease) may disrupt both Gram-type biofilms. An additional common feature is the presence of membrane vesicles, and the potential of these vesicles requires further investigation. Genetic regulation by c-di-GMP is prominent in Gram-negative bacteria. However, quorum sensing (QS) may play a common regulation during biofilms dispersal. These studies are significant not only for common therapeutic against mixed biofilms, but for better understanding of bacterial interactions within natural or host infection environment as well.}, } @article {pmid34330075, year = {2022}, author = {Molaei, S and Moussavi, G and Talebbeydokhti, N and Shekoohiyan, S}, title = {Biodegradation of the petroleum hydrocarbons using an anoxic packed-bed biofilm reactor with in-situ biosurfactant-producing bacteria.}, journal = {Journal of hazardous materials}, volume = {421}, number = {}, pages = {126699}, doi = {10.1016/j.jhazmat.2021.126699}, pmid = {34330075}, issn = {1873-3336}, mesh = {Bacteria ; Biodegradation, Environmental ; Biofilms ; Hydrocarbons ; *Petroleum ; }, abstract = {The present study employed an anoxic packed bed biofilm reactor (AnPBR) inoculated with in-situ biosurfactant-producing bacteria for the biodegradation of petroleum wastewater. Highly acclimated biomass decreased the start-up phase period and with increasing the initial total petroleum hydrocarbon (TPH) concentration from 1.5 to 4 g/L was accompanied by TPH and chemical oxygen demand (COD) removal efficiencies of above 99% and 96%, respectively. Decreasing hydraulic retention time (HRT) from 24 to 6 h caused an increase in the specific hydrocarbon utilization rate value from 0.45 to 1.66 gTPH/gbiomass.d. Moreover, dehydrogenase activity, surfactin, and rhamnolipid reached 31.8 μgTF/gbiomass.d, 95.1, and 27.1 mg/L, respectively. The biodegradation kinetic coefficients such as K, Ks, Kd, Y and µmax were 0.784 (d[-1]), 0.005 (g/L), 0.138 (d[-1]), 0.569 (gVSS/gCOD), and 0.446 (d[-1]), respectively. Dropping of bioreactor performance, especially TPH removal efficiency from 99% to 37.6% in the absence of nitrate after 10 days, indicates anoxic metabolism has been the dominant biodegradation pathway. The effluent chromatogram of gas chromatography/flame ionization detector (GC/FID) showed aliphatic, cyclic aliphatic, and aromatic hydrocarbons efficiently degraded. According to the high degradation rate of AnPBR in different operational parameters, it can be recommended for the treatment of oil-contaminated wastewater.}, } @article {pmid34329932, year = {2021}, author = {Guo, K and Wu, N and Li, W and Baattrup-Pedersen, A and Riis, T}, title = {Microbial biofilm community dynamics in five lowland streams.}, journal = {The Science of the total environment}, volume = {798}, number = {}, pages = {149169}, doi = {10.1016/j.scitotenv.2021.149169}, pmid = {34329932}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; Hydrology ; *Microbiota ; *Rivers ; }, abstract = {Stream biofilms are complex aggregates of diverse organism groups that play a vital role in global carbon and nitrogen cycles. Most of the current studies on stream biofilm focus on a limited number of organism groups (e.g., bacteria and algae), and few have included both prokaryote and eukaryote communities simultaneously. In this study, we incubated artificial substrates in five Danish lowland streams exhibiting different hydrological and physico-chemical conditions and explored the dynamics of community composition and diversity of the benthic biofilm, including both prokaryotes and eukaryotes. We found that few phyla in the prokaryote (Gammaproteobacteria and Bacteroidetes) and eukaryote (Cercozoa) communities accounted for over two-thirds of the total abundance at most of the sites. Both prokaryotic and eukaryotic diversity displayed the same temporal patterns, i.e., diversity peaked in July and January. We also found that hydrological and physico-chemical variables significantly explained the variation in the community composition at phylum level for both prokaryotes and eukaryotes. However, a large proportion of variation remained unexplained, which can be ascribed to important but unmeasured variables like light intensity and biological factors such as trophic and non-trophic interactions as revealed by network analysis. Therefore, we suggest that use of a multitrophic level perspective is needed to study biofilm i.e., the "microbial jungles", where high occurrences of trophic and non-trophic interactions are expected.}, } @article {pmid34328615, year = {2022}, author = {Doub, JB and Wilson, E}, title = {Observed transaminitis with a unique bacteriophage therapy protocol to treat recalcitrant Staphylococcal biofilm infections.}, journal = {Infection}, volume = {50}, number = {1}, pages = {281-283}, pmid = {34328615}, issn = {1439-0973}, mesh = {Biofilms ; Humans ; *Phage Therapy/methods ; *Staphylococcal Infections/therapy ; }, } @article {pmid34328559, year = {2022}, author = {Ayoub, HM and Gregory, RL and Tang, Q and Lippert, F}, title = {The influence of biofilm maturation on fluoride's anticaries efficacy.}, journal = {Clinical oral investigations}, volume = {26}, number = {2}, pages = {1269-1282}, pmid = {34328559}, issn = {1436-3771}, mesh = {Animals ; Biofilms ; Cariostatic Agents ; Cattle ; *Fluorides/pharmacology ; Humans ; Sodium Fluoride/pharmacology ; Tin Fluorides/pharmacology ; *Tooth Demineralization/prevention & control ; Tooth Remineralization ; }, abstract = {OBJECTIVES: (1) To explore the influence of biofilm maturation and timing of exposure on fluoride anticaries efficacy and (2) to explore biofilm recovery post-treatment.

METHODS: Bovine enamel specimens were utilized in a pH cycling model (28 subgroups [n = 18]). Each subgroup received different treatments [exposure]: sodium fluoride [NaF]; stannous fluoride [SnF2]; amine fluoride [AmF]; and de-ionized water [DIW], at a specific period: early: days 1-4; middle: days 3-6; and late: days 7-10. During non-exposure periods, pH cycling included DIW instead of fluorides. Objective 1: part 1 (cycling for 4, 6, or 10 days). Part 2 (cycling for 10 days). Objective 2: early exposure: three sample collection time points (immediate, 3 days, and 6 days post-treatment); middle exposure: two sample collection time points (immediate, 4 days post-treatment). The enamel and biofilm were analyzed ([surface microhardness; mineral loss; lesion depth]; [lactate dehydrogenase enzyme activity; exopolysaccharide amount; viability]). Data were analyzed using ANOVA (p = 0.05).

RESULTS: Objective 1: Early exposure to fluorides produced protective effects against lesion progression in surface microhardness and mineral loss, but not for lesion depth. Objective 2: Early exposure slowed the demineralization process. SnF2 and AmF were superior to NaF in reducing LDH and EPS values, regardless of exposure time. They also prevented biofilm recovery.

CONCLUSION: Earlier exposure to SnF2 and AmF may result in less tolerant biofilm. Early fluoride treatment may produce a protective effect against demineralization. SnF2 and AmF may be the choice to treat older biofilm and prevent biofilm recovery.

CLINICAL RELEVANCE: The study provides an understanding of biofilm-fluoride interaction with mature biofilm (e.g., hard-to-reach areas, orthodontic patients) and fluoride's sustainable effect hours/days after brushing.}, } @article {pmid34328083, year = {2021}, author = {Delacuvellerie, A and Benali, S and Cyriaque, V and Moins, S and Raquez, JM and Gobert, S and Wattiez, R}, title = {Microbial biofilm composition and polymer degradation of compostable and non-compostable plastics immersed in the marine environment.}, journal = {Journal of hazardous materials}, volume = {419}, number = {}, pages = {126526}, doi = {10.1016/j.jhazmat.2021.126526}, pmid = {34328083}, issn = {1873-3336}, mesh = {Biodegradation, Environmental ; Biofilms ; *Composting ; Plastics ; *Polymers ; }, abstract = {Different plastic types considered as compostable are found on the market such as petro-based (e.g., polybutylene adipate terephthalate (PBAT)) or bio-based plastics (e.g., polylactic acid, (PLA)). Even if their degradation has been confirmed in industrial compost conditions, investigation of their degradation in natural marine environment has been limited. To better understand biodegradation into natural marine environment, commercial compostable (PBAT, semi-crystalline and amorphous PLA) and non-compostable polymers (low density polyethylene, polystyrene, polyethylene terephthalate, polyvinyl chloride) were submerged in situ on the sediment and in the water column in the Mediterranean Sea. These samples were studied by chemical and microbiological approaches. After 82 days of immersion, no significant bacterial degradation of the different polymers was observed, except some abiotic alterations of PBAT and LDPE probably due to a photooxidation process. However, after 80 days in an enrichment culture containing plastic films as a main carbon source, Marinomonas genus was specifically selected on the PBAT and a weight loss of 12% was highlighted. A better understanding of the bacterial community colonizing these plastics is essential for an eco-design of new biodegradable polymers to allow a rapid degradation in aquatic environment.}, } @article {pmid34323486, year = {2021}, author = {Xuan, TF and Wang, ZQ and Liu, J and Yu, HT and Lin, QW and Chen, WM and Lin, J}, title = {Design and Synthesis of Novel c-di-GMP G-Quadruplex Inducers as Bacterial Biofilm Inhibitors.}, journal = {Journal of medicinal chemistry}, volume = {64}, number = {15}, pages = {11074-11089}, doi = {10.1021/acs.jmedchem.1c00465}, pmid = {34323486}, issn = {1520-4804}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Benzothiazoles/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cyclic GMP/*analogs & derivatives/metabolism ; Dose-Response Relationship, Drug ; Drug Design ; G-Quadruplexes/drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas aeruginosa/*drug effects/metabolism ; Quinolines/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {The formation of biofilms by clinical pathogens typically leads to chronic and recurring antibiotic-resistant infections. High cellular levels of cyclic diguanylate (c-di-GMP), a ubiquitous secondary messenger of bacteria, have been proven to be associated with a sessile biofilm lifestyle of pathogens. A promising antibiofilm strategy involving the induction of c-di-GMP to form dysfunctional G-quadruplexes, thereby blocking the c-di-GMP-mediated biofilm regulatory pathway, was proposed in this study. In this new strategy, a series of novel c-di-GMP G-quadruplex inducers were designed and synthesized for development of therapeutic biofilm inhibitors. Compound 5h exhibited favorable c-di-GMP G-quadruplex-inducing activity and 62.18 ± 6.76% biofilm inhibitory activity at 1.25 μM without any DNA intercalation effect. Moreover, the favorable performance of 5h in interfering with c-di-GMP-related biological functions, including bacterial motility and bacterial extracellular polysaccharide secretion, combined with the reporter strain and transcriptome analysis results confirmed the c-di-GMP signaling-related action mechanism of 5h.}, } @article {pmid34323245, year = {2021}, author = {Guo, J and Xu, Y and Liu, M and Yu, J and Yang, H and Lei, W and Huang, C}, title = {An MSN-based synergistic nanoplatform for root canal biofilm eradication via Fenton-enhanced sonodynamic therapy.}, journal = {Journal of materials chemistry. B}, volume = {9}, number = {37}, pages = {7686-7697}, doi = {10.1039/d1tb01031j}, pmid = {34323245}, issn = {2050-7518}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/pharmacology ; Biocompatible Materials/*chemistry/pharmacology ; Biofilms/drug effects ; Cell Line ; Cell Survival/drug effects ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis/physiology ; Hydrogen Peroxide/*chemistry/pharmacology ; Iron/*chemistry ; Methylene Blue/chemistry ; Mice ; Nanoparticles/*chemistry ; Porosity ; Protoporphyrins/chemistry ; Reactive Oxygen Species/metabolism ; Root Canal Therapy/methods ; Silicon Dioxide/*chemistry ; Staphylococcus aureus/drug effects ; Ultrasonography ; }, abstract = {The validity and biocompatibility of irrigating agents are imperative for the success of root canal therapy. The imperfections in the currently available irrigants highlight the fact that more advanced technologies and strategies are required for complete disinfection in endodontic treatments. In the present study, a Fenton reaction-enhanced antimicrobial sonodynamic therapy (SDT) platform was fabricated for root canal disinfection. Firstly, mesoporous silica nanoparticles (MSNs) were synthesized, grafted with an amino group and then conjugated with sonosensitizer protoporphyrin IX (PpIX). Iron ions were then anchored (M@P-Fe) to initiate a Fenton reaction. Nanoparticle characterization by size and zeta potential measurements, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis confirmed that the platform was successfully developed. Reactive oxygen species (ROS) generation assessment, methylene blue degradation and electron spin resonance assays illustrated upon ultrasound (US) irradiation, that augmented ROS, can be produced by US activated PpIX and iron mediated Fenton reactions from low concentration H2O2 (0.01%). In vitro anti-Enterococcus faecalis efficacy was demonstrated by growth curve and colony forming unit measurements. Confocal laser scanning microscopy and scanning electron microscopy observations illustrated the effectiveness of the platform on in situ biofilm eradication in root canal. Owing to the stronger oxidizing capability and short lifetime of ROS, the Fenton reaction-enhanced SDT can induce detrimental oxidative damage to bacteria upon activation of US while avoiding nonspecific toxicity to cells, which was verified by cytotoxicity evaluations using CCK-8 assay and morphology observation of MC3T3-E1 cells. Compared to commonly used NaClO, this nanoplatform displayed desirable anti-bacterial, anti-biofilm abilities and better biocompatibility. These results highlight that the integrated M@P-Fe + US + H2O2 platform is a promising candidate for US enhanced root canal irrigation and disinfection.}, } @article {pmid34323037, year = {2021}, author = {Dong, YT and Li, PY and Sun, YY and Rao, YQ and Yu, SH and Hu, HY}, title = {[Biofilm Eradication Four-Step Strategy: Study of Using Self-Assembled Azithromycin/Rhamnolipid Nanoparticles for Removing Pseudomonas aeruginosa Biofilm].}, journal = {Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition}, volume = {52}, number = {4}, pages = {598-604}, doi = {10.12182/20210760207}, pmid = {34323037}, issn = {1672-173X}, mesh = {Anti-Bacterial Agents/pharmacology ; Azithromycin/pharmacology ; Biofilms ; Glycolipids ; Humans ; Microbial Sensitivity Tests ; *Nanoparticles ; *Pseudomonas aeruginosa ; }, abstract = {OBJECTIVE: To investigate the in vitro eradicative effect of self-assembled azithromycin/rhamnolipid nanoparticles (AZI-RHL NPs) on P seudomonas aeruginosa (P. aeruginosa) biofilm.

METHODS: AZI-RHL NPs were prepared and characterized. The minimum inhibitory concentration (MIC) of AZI-RHL NPs on planktonic P. aeruginosa was measured by the broth microdilution method. The eradicative effect of AZI-RHL NPs on P. aeruginosa biofilm was evaluated via crystal violet staining and SYTO 9/PI live/dead staining. Fluorescence labeling was used to measure the eradicative effect of NPs on extracellular polymeric substances (EPS). In addition, crystal violet staining was performed to evaluate the inhibitory effect of AZI-RHL NPs on the adhesion of P. aeruginosa on human bronchial epithelial BEAS-2B cells. To investigate the ability of AZI-RHL NPs to penetrate mucus, the interaction between NPs and mucin was measured via particle size changes after co-incubation with mucin solution.

RESULTS: The AZI-RHL NPs had a particle size of about 121 nm and were negatively charged on the surface, displaying a high encapsulation efficiency and a high drug loading capacity of 96.72% and 45.08% for AZI, respectively and 99.38% and 53.07% for RHL, respectively. The MIC of AZI-RHL NPs on planktonic P. aeruginosa was half of that of using AZI alone. AZI-RHL NPs displayed the capacity to effectively destroy the biofilm structure and remove the proteins and polysaccharides in EPS, eradicating biofilms in addition to reducing the survival rate of bacteria in the biofilm. AZI-RHL NPs were shown to have inhibited P. aeruginosa adhesion on BEAS-2B cells and prevented the residual bacteria from forming a new biofilm. There was no significant change in the particle size of NPs after co-incubation with mucin solution, indicating a weak interaction between NPs and mucin, and suggesting that NPs could penetrate the mucus and reach the P. aeruginosa infection sites.

CONCLUSION: AZI-RHL NPs were able to effectively enhance the removal of P. aeruginosa biofilm through a four-step strategy of biofilm eradication, including penetrating the mucus, disintegrating the biofilm structure, killing the bacteria dispersed from biofilm, and preventing the adhesion of residual bacteria. We hope that this study will provide a replicable common strategy for the treatment of refractory infections caused by P. aeruginosa and other types of biofilms.}, } @article {pmid34322213, year = {2021}, author = {Khoshkhounejad, M and Sharifian, M and Assadian, H and Afshar, MS}, title = {Antibacterial effectiveness of diluted preparations of intracanal medicaments used in regenerative endodontic treatment on dentin infected by bacterial biofilm: An ex vivo investigation.}, journal = {Dental research journal}, volume = {18}, number = {}, pages = {37}, pmid = {34322213}, issn = {1735-3327}, abstract = {BACKGROUND: Conventional drug mixtures used in regenerative endodontic procedures have a toxic effect and no consensus has been reached about their best composition and concentration. Therefore, the aim of this study was to determine minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm inhibitory concentration (MBIC) of the antimicrobial preparations and to compare their antimicrobial efficacy on bovine dentin infected by Enterococcus faecalis.

MATERIALS AND METHODS: For this original ex vivo investigation, prepared concentrations (MIC, MBC, and MBIC) of triple antibiotic paste (TAP), double antibiotic paste (DAP), modified triple antibiotic paste (MTAP)-1, MTAP2, co-amoxiclav, and calcium hydroxide (CH) were added to the prepared bovine dentin blocks (which incubated in E. faecalis suspension previously) and incubated for 3 days. The samples were subsequently prepared for culture and CFU counts. Statistical analysis of data was carried out using one-way analysis of variance and post hoc tests. The statistical power was set at P < 0.05.

RESULTS: All medicament groups significantly showed an antimicrobial efficacy compared with negative control (without antibiotic) (P < 0.001). TAP, DAP, co-amoxiclav, and CH (at its MBC value) were significantly capable of eliminating E. faecalis biofilm and showed no significant difference in comparison with positive control (complete biofilm removal) (P < 0.05).

CONCLUSION: TAP, DAP, co-amoxiclav, and CH (at its MBC value) could effectively eliminate biofilm bacteria on the dentin surface. Antimicrobial efficacy of other medicaments containing cefaclor or clindamycin was limited.}, } @article {pmid34321357, year = {2021}, author = {Melia, CE and Bolla, JR and Katharios-Lanwermeyer, S and Mihaylov, DB and Hoffmann, PC and Huo, J and Wozny, MR and Elfari, LM and Böhning, J and Morgan, AN and Hitchman, CJ and Owens, RJ and Robinson, CV and O'Toole, GA and Bharat, TAM}, title = {Architecture of cell-cell junctions in situ reveals a mechanism for bacterial biofilm inhibition.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {118}, number = {31}, pages = {}, pmid = {34321357}, issn = {1091-6490}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; 202231/Z/16/Z/WT_/Wellcome Trust/United Kingdom ; MR/N020413/1/MRC_/Medical Research Council/United Kingdom ; R01 GM123609/GM/NIGMS NIH HHS/United States ; /WT_/Wellcome Trust/United Kingdom ; MC_UP_1201/10/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Bacterial Adhesion ; Biofilms/*growth & development ; Cell Membrane ; Extracellular Matrix ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*physiology ; Single-Domain Antibodies ; }, abstract = {Many bacteria, including the major human pathogen Pseudomonas aeruginosa, are naturally found in multicellular, antibiotic-tolerant biofilm communities, in which cells are embedded in an extracellular matrix of polymeric molecules. Cell-cell interactions within P. aeruginosa biofilms are mediated by CdrA, a large, membrane-associated adhesin present in the extracellular matrix of biofilms, regulated by the cytoplasmic concentration of cyclic diguanylate. Here, using electron cryotomography of focused ion beam-milled specimens, we report the architecture of CdrA molecules in the extracellular matrix of P. aeruginosa biofilms at intact cell-cell junctions. Combining our in situ observations at cell-cell junctions with biochemistry, native mass spectrometry, and cellular imaging, we demonstrate that CdrA forms an extended structure that projects from the outer membrane to tether cells together via polysaccharide binding partners. We go on to show the functional importance of CdrA using custom single-domain antibody (nanobody) binders. Nanobodies targeting the tip of functional cell-surface CdrA molecules could be used to inhibit bacterial biofilm formation or disrupt preexisting biofilms in conjunction with bactericidal antibiotics. These results reveal a functional mechanism for cell-cell interactions within bacterial biofilms and highlight the promise of using inhibitors targeting biofilm cell-cell junctions to prevent or treat problematic, chronic bacterial infections.}, } @article {pmid34320877, year = {2021}, author = {Qian, W and Li, X and Yang, M and Mao, G}, title = {Antibacterial and anti-biofilm activities of paeonol against Klebsiella pneumoniae and Enterobacter cloacae.}, journal = {Biofouling}, volume = {37}, number = {6}, pages = {666-679}, doi = {10.1080/08927014.2021.1955249}, pmid = {34320877}, issn = {1029-2454}, mesh = {Acetophenones ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Enterobacter cloacae ; *Klebsiella pneumoniae ; Microbial Sensitivity Tests ; }, abstract = {Paeonol, the active ingredient of Paeonia lactiflora root bark, is widely used in traditional Chinese medicine. Few studies have reported the antibacterial activity of paeonol against bacterial pathogens. In this study, the antibacterial and anti-biofilm performance of paeonol against Klebsiella pneumoniae and Enterobacter cloacae was investigated as well as its mechanisms of action. Paeonol effectively inhibited the growth of K. pneumoniae and E. cloacae with a minimum inhibitory concentration of 64 μg ml[-1] and it was shown to disrupt the integrity of bacterial cell membranes, and alter cell morphology. Moreover, paeonol exhibited a potent inhibitory effect against adhesion and biofilm formation by K. pneumoniae and E. cloacae. In particular, paeonol efficiently compromised cells within biofilms, and dispersed mature biofilms. Therefore, the present study suggests that paeonol is a promising alternative antibacterial and anti-biofilm agent for combating infections caused by planktonic and biofilm cells of K. pneumoniae and E. cloacae.}, } @article {pmid34319637, year = {2022}, author = {Nedelea, AG and Plant, RL and Robins, LI and Maddocks, SE}, title = {Testing the efficacy of topical antimicrobial treatments using a two- and five-species chronic wound biofilm model.}, journal = {Journal of applied microbiology}, volume = {132}, number = {1}, pages = {715-724}, doi = {10.1111/jam.15239}, pmid = {34319637}, issn = {1365-2672}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms ; Humans ; Pseudomonas aeruginosa ; Staphylococcus aureus ; *Wound Infection/drug therapy ; }, abstract = {AIMS: The effectiveness of commercially available wound dressings and a HOCl gel formulation was tested against two- and five-species biofilms in a dynamic in vitro chronic wound infection model.

METHOD: Two-species biofilms (Pseudomonas aeruginosa and Staphylococcus aureus) were cultured using a biofilm flow device and treated with wound dressings containing silver, iodine, polyhexamethylene biguanide, crystal violet or HOCl gel at 5 h. Five-species biofilms (P. aeruginosa, S. aureus, Enterococcus faecalis, Streptococcus pyogenes and Escherichia coli) were similarly cultured and treated with HOCl gel at 5 and 24 h. Multidose experiments used two- and five-species biofilms with HOCl applied at 24, 48 and 72 h.

RESULTS: None of the treatments completely disrupted the biofilms and, with the exception of silver, bacteria recovered in number post-treatment. HOCl was most effective when applied to 24 h established biofilms with most activity against P. aeruginosa. Recovery post-treatment was negligible with HOCl applied at 24 h and multiple doses indicated that bacteria were not becoming tolerant to treatment.

CONCLUSIONS: Realistic models are necessary to test the effectiveness of antimicrobial wound treatments to ensure findings are clinically translatable. HOCl gel shows promise as a new topical antimicrobial for wounds, especially due to its ability to inhibit P. aeruginosa.

This study highlights a need for robust in vitro data to support development and use of wound treatments that can only be obtained from the refinement of realistic infection models. Furthermore, it indicates the potential use of HOCl gel for chronic wound management.}, } @article {pmid34319146, year = {2021}, author = {Marinković, J and Nikolić, B and Marković, T and Radunović, M and Ilić, J and Bošković, M and Ćirić, A and Marković, D}, title = {Cymbopogon citratus essential oil: an active principle of nanoemulsion against Enterococcus faecalis root canal biofilm.}, journal = {Future microbiology}, volume = {16}, number = {}, pages = {907-918}, doi = {10.2217/fmb-2021-0081}, pmid = {34319146}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/pharmacology ; Antioxidants/pharmacology ; Biofilms/drug effects ; *Cymbopogon/chemistry ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*drug effects ; Humans ; *Oils, Volatile/pharmacology ; Plant Oils/*pharmacology ; Root Canal Therapy ; }, abstract = {Aim: The objective was to formulate and characterize the nanoemulsion based on Cymbopogon citratus oil, intended for use in infected teeth root canal therapy. The investigation of the antioxidant and antibiofilm potential toward Enterococcus faecalis was aimed as well. Materials & methods: Characterization of oil (by GC/MS analysis) and nanoemulsion (by dynamic light scattering instrument), and determination of antibacterial (by microdilution assay), antibiofilm (by crystal violet assay) and antioxidant properties (by 2,2-diphenyl-1-picryl-hydrazyl-hydrate and thiobarbituric acid assay methods) were provided. Antibiofilm efficacy of irrigation procedure including nanoemulsion was screened on extracted teeth (by CFU-counting assay). Results: Notable antibacterial and antibiofilm activity, both against forming and preformed biofilms of oil, was observed. Irrigation involved nanoemulsion showed remarkable antibiofilm potential. Both substances induced some antioxidant activity. Conclusion: Results encourage further research with the aim of application of the nanoemulsion in dental practice.}, } @article {pmid34319073, year = {2021}, author = {Alabresm, A and Chandler, SL and Benicewicz, BC and Decho, AW}, title = {Nanotargeting of Resistant Infections with a Special Emphasis on the Biofilm Landscape.}, journal = {Bioconjugate chemistry}, volume = {32}, number = {8}, pages = {1411-1430}, pmid = {34319073}, issn = {1520-4812}, support = {R01 AI149810/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/pharmacology/therapeutic use ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Drug Carriers/*chemistry ; Drug Delivery Systems ; Drug Resistance, Bacterial/drug effects ; Humans ; Nanoparticles/*chemistry ; }, abstract = {Bacterial resistance to antimicrobial compounds is a growing concern in medical and public health circles. Overcoming the adaptable and duplicative resistance mechanisms of bacteria requires chemistry-based approaches. Engineered nanoparticles (NPs) now offer unique advantages toward this effort. However, most in situ infections (in humans) occur as attached biofilms enveloped in a protective surrounding matrix of extracellular polymers, where survival of microbial cells is enhanced. This presents special considerations in the design and deployment of antimicrobials. Here, we review recent efforts to combat resistant bacterial strains using NPs and, then, explore how NP surfaces may be specifically engineered to enhance the potency and delivery of antimicrobial compounds. Special NP-engineering challenges in the design of NPs must be overcome to penetrate the inherent protective barriers of the biofilm and to successfully deliver antimicrobials to bacterial cells. Future challenges are discussed in the development of new antibiotics and their mechanisms of action and targeted delivery via NPs.}, } @article {pmid34314810, year = {2021}, author = {de Freitas, SB and Wozeak, DR and Neto, AS and Cardoso, TL and Hartwig, DD}, title = {A hypothetical adhesin protein induces anti-biofilm antibodies against multi-drug resistant Acinetobacter baumannii.}, journal = {Microbial pathogenesis}, volume = {159}, number = {}, pages = {105112}, doi = {10.1016/j.micpath.2021.105112}, pmid = {34314810}, issn = {1096-1208}, mesh = {*Acinetobacter Infections/prevention & control ; *Acinetobacter baumannii ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Mice ; Microbial Sensitivity Tests ; *Pharmaceutical Preparations ; }, abstract = {The increase in multidrug-resistant (MDR) Acinetobacter baumannii strains in hospital environments has generated great concern around the world. Biofilm is one of the forms of bacterial adaptation that is increasingly leading to antimicrobial resistance and therapeutic failure. The search for alternative therapeutic strategies, especially non-antibiotic-based, is urgently needed. In this study, we produce polyclonal antibodies (pAbs) in murine models against recombinant CAM87009.1 antigen, an A. baumannii fimbriae protein. The pAbs produced were isotyped and anti-biofilm activity evaluated in the A. baumannii ATCC® 19606 standard strain and nine MDR clinical isolates. All clinical isolates were analyzed for the presence of the cam87009.1 gene using the PCR technique, and one of the isolates did not have the gene in its genome. After four intraperitoneal immunizations (days 0, 14, 21, and 28) of mice with rCAM87009.1 and Freund's adjuvant, a significant antibody titer was detected by indirect enzyme-linked immunosorbent assay (ELISA) since the first immunization (1:6400), and the level increased until the 4th immunization (1:819,200). IgM, IgA, IgG1, IgG2a, IgG2b, and IgG3 isotypes were identified in the serum of immunized mice (P < 0.001). The anti-rCAM87009.1 pAb was able to inhibit biofilm formation in 80 % of the strains evaluated in this study, including the ATCC® 19606 strain. The rCAM87009.1 proves to be a promising target in the development of alternative strategies to control biofilm-forming in A. baumannii MDR strains.}, } @article {pmid34313942, year = {2021}, author = {Samandoulgou, I and Vimont, A and Fernandez, B and Fliss, I and Jean, J}, title = {Murine Norovirus Interaction with Pseudomonas aeruginosa Biofilm in a Dynamic Bioreactor.}, journal = {Food and environmental virology}, volume = {13}, number = {4}, pages = {485-492}, pmid = {34313942}, issn = {1867-0342}, mesh = {Animals ; Biofilms ; Bioreactors ; Culture Media ; Mice ; *Norovirus/genetics ; *Pseudomonas aeruginosa/genetics ; }, abstract = {Biofilms can constitute permanent threats to food safety and public health. Bacteria and viruses lodged in biofilm can escape cleaning and sanitizing agents. The aim of this study was to compare Pseudomonas aeruginosa developing and mature biofilms produced on agri-food surfaces in terms of interaction with murine norovirus. Whether they were mature or still developing the biofilms apparently accumulated murine norovirus in large numbers after 24 h of contact with medium which viral titer was 2.6 × 10[4] pfu ml[-1] (≈ 8 log10 genome copies ml[-1]). This appeared unrelated to surfaces' nature and bacterial viable count but related to polysaccharide and protein contents. Virus releases may also occur mainly in connection with P. aeruginosa biofilm dispersal systems. These findings suggest that the effectiveness of surface cleaning agents and procedures for reducing the risks of biofilms-related viral contaminations need to be re-evaluated in relation with biofilm components. However, more repetitions and further in-depth specific studies are needed for confirmation of these findings and more clarifications on virus-biofilm interaction phenomenon.}, } @article {pmid34313584, year = {2021}, author = {Borsanelli, AC and Athayde, FRF and Agostinho, SD and Riggio, MP and Dutra, IS}, title = {Dental biofilm and its ecological interrelationships in ovine periodontitis.}, journal = {Journal of medical microbiology}, volume = {70}, number = {7}, pages = {}, doi = {10.1099/jmm.0.001396}, pmid = {34313584}, issn = {1473-5644}, mesh = {Animals ; Bacteria/*genetics ; Biofilms/*growth & development ; Ecology ; High-Throughput Nucleotide Sequencing/methods ; Microbiota/genetics ; Periodontitis/*microbiology ; RNA, Ribosomal, 16S/genetics ; Sheep/*microbiology ; }, abstract = {Introduction. Periodontitis, one of the most common oral disorders in sheep, is caused by a mixed and opportunistic microbiota that severely affects the health and welfare of animals. However, little is known about the ecological processes involved and the composition of the microbiota associated with the development of the disease.Hypothesis/Gap Statement. Using high-throughput sequencing of the 16S ribosomal RNA gene and network analysis it would be possible to discriminate the microbiomes of clinically healthy sheep and those with periodontitis and possibly identify the key microorganisms associated with the disease.Aim. The present study aimed to characterise the composition of dental microbiomes and bacterial co-occurrence networks in clinically healthy sheep and animals with periodontitis.Methodology. Dental biofilm samples were collected from ten sheep with periodontitis and ten clinically healthy animals. Bacteria were identified using high-throughput sequencing of the 16S ribosomal RNA gene.Results. The most prevalent genera in the dental microbiota of sheep with periodontitis were Petrimonas, Acinetobacter, Porphyromonas and Aerococcus. In clinically healthy animals, the most significant genera were unclassified Pasteurellaceae, Pseudomonas, and Neisseria. Fusobacterium was found at high prevalence in the microbiomes of both groups. The dental microbiota of sheep in the two clinical conditions presented different profiles and the diversity and richness of bacteria was greater in the diseased animals. Network analyses showed the presence of a large number of antagonistic interactions between bacteria in the dental microbiota of animals with periodontitis, indicating the occurrence of a dysbiotic community. Through the interrelationships, members of the Prevotella genus are likely to be key pathogens, both in the dental microbiota of healthy animals and those with periodontitis. Porphyromonas stood out among the top three nodes with more centrality and the largest number of hubs in the networks of animals with periodontitis.Conclusion. The dental biofilm microbiota associated with ovine periodontitis is dysbiotic and with significant antagonistic interactions, which discriminates healthy animals from diseased animals and highlights the importance of key bacteria, such as Petrimonas, Porphyromonas, Prevotella and Fusobacterium species.}, } @article {pmid34311995, year = {2021}, author = {Banerjee, P and Sahoo, PK and Sheenu, and Adhikary, A and Ruhal, R and Jain, D}, title = {Molecular and structural facets of c-di-GMP signalling associated with biofilm formation in Pseudomonas aeruginosa.}, journal = {Molecular aspects of medicine}, volume = {81}, number = {}, pages = {101001}, doi = {10.1016/j.mam.2021.101001}, pmid = {34311995}, issn = {1872-9452}, mesh = {Biofilms ; *Cyclic GMP ; Humans ; Phosphoric Diester Hydrolases/metabolism ; *Pseudomonas aeruginosa/metabolism ; Signal Transduction ; }, abstract = {Pseudomonas aeruginosa is an opportunistic human pathogen and is the primary cause of nosocomial infections. Biofilm formation by this organism results in chronic and hard to eradicate infections. The intracellular signalling molecule bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a secondary messenger in bacterial cells crucial for motile to sessile transition. The signalling pathway components encompass two classes of enzymes with antagonistic activities, the diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) that regulate the cellular levels of c-di-GMP at distinct stages of biofilm initiation, maturation and dispersion. This review summarizes the structural analysis and functional studies of the DGCs and PDEs involved in biofilm regulation in P. aeruginosa. In addition, we also describe the effector proteins that sense the perturbations in c-di-GMP levels to elicit a functional output. Finally, we discuss possible mechanisms that allow the dynamic levels of c-di-GMP to regulate cognate cellular response. Uncovering the details of the regulation of the c-di-GMP signalling pathway is vital for understanding the behaviour of the pathogen and characterization of novel targets for anti-biofilm interventions.}, } @article {pmid34311706, year = {2021}, author = {Redfern, J and Wallace, J and van Belkum, A and Jaillard, M and Whittard, E and Ragupathy, R and Verran, J and Kelly, P and Enright, MC}, title = {Biofilm associated genotypes of multiple antibiotic resistant Pseudomonas aeruginosa.}, journal = {BMC genomics}, volume = {22}, number = {1}, pages = {572}, pmid = {34311706}, issn = {1471-2164}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Drug Resistance, Multiple, Bacterial ; Genotype ; Humans ; Pseudomonas Infections ; *Pseudomonas aeruginosa/drug effects/genetics ; Quorum Sensing ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is a ubiquitous environmental microorganism and also a common cause of infection. Its ability to survive in many different environments and persistently colonize humans is linked to its presence in biofilms formed on indwelling device surfaces. Biofilm promotes adhesion to, and survival on surfaces, protects from desiccation and the actions of antibiotics and disinfectants.

RESULTS: We examined the genetic basis for biofilm production on polystyrene at room (22 °C) and body temperature (37 °C) within 280 P. aeruginosa. 193 isolates (69 %) produced more biofilm at 22 °C than at 37 °C. Using GWAS and pan-GWAS, we found a number of accessory genes significantly associated with greater biofilm production at 22 °C. Many of these are present on a 165 kb region containing genes for heavy metal resistance (arsenic, copper, mercury and cadmium), transcriptional regulators and methytransferases. We also discovered multiple core genome SNPs in the A-type flagellin gene and Type II secretion system gene xpsD. Analysis of biofilm production of isolates of the MDR ST111 and ST235 lineages on stainless-steel revealed several accessory genes associated with enhanced biofilm production. These include a putative translocase with homology to a Helicobacter pylori type IV secretion system protein, a TA system II toxin gene and the alginate biosynthesis gene algA, several transcriptional regulators and methytransferases as well as core SNPs in genes involved in quorum sensing and protein translocation.

CONCLUSIONS: Using genetic association approaches we discovered a number of accessory genes and core-genome SNPs that were associated with enhanced early biofilm formation at 22 °C compared to 37 °C. These included a 165 kb genomic island containing multiple heavy metal resistance genes, transcriptional regulators and methyltransferases. We hypothesize that this genomic island may be associated with overall genotypes that are environmentally adapted to survive at lower temperatures. Further work to examine their importance in, for example gene-knockout studies, are required to confirm their relevance. GWAS and pan-GWAS approaches have great potential as a first step in examining the genetic basis of novel bacterial phenotypes.}, } @article {pmid34311545, year = {2021}, author = {Betsholtz, A and Karlsson, S and Svahn, O and Davidsson, Å and Cimbritz, M and Falås, P}, title = {Tracking [14]C-Labeled Organic Micropollutants to Differentiate between Adsorption and Degradation in GAC and Biofilm Processes.}, journal = {Environmental science & technology}, volume = {55}, number = {16}, pages = {11318-11327}, pmid = {34311545}, issn = {1520-5851}, abstract = {Granular activated carbon (GAC) filters can be used to reduce emissions of organic micropollutants via municipal wastewater, but it is still uncertain to which extent biological degradation contributes to their removal in GAC filters. [14]C-labeled organic micropollutants were therefore used to distinguish degradation from adsorption in a GAC-filter media with associated biofilm. The rates and extents of biological degradation and adsorption were investigated and compared with other biofilm systems, including a moving bed biofilm reactor (MBBR) and a sand filter, by monitoring [14]C activities in the liquid and gas phases. The microbial cleavage of ibuprofen, naproxen, diclofenac, and mecoprop was confirmed for all biofilms, based on the formation of [14]CO2, whereas the degradation of [14]C-labeled moieties of sulfamethoxazole and carbamazepine was undetected. Higher degradation rates for diclofenac were observed for the GAC-filter media than for the other biofilms. Degradation of previously adsorbed diclofenac onto GAC could be confirmed by the anaerobic adsorption and subsequent aerobic degradation by the GAC-bound biofilm. This study demonstrates the potential use of [14]C-labeled micropollutants to study interactions and determine the relative contributions of adsorption and degradation in GAC-based treatment systems.}, } @article {pmid34311409, year = {2021}, author = {Maurya, A and Kumar, R and Singh, A and Raj, A}, title = {Investigation on biofilm formation activity of Enterococcus faecium under various physiological conditions and possible application in bioremediation of tannery effluent.}, journal = {Bioresource technology}, volume = {339}, number = {}, pages = {125586}, doi = {10.1016/j.biortech.2021.125586}, pmid = {34311409}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; Biofilms ; *Enterococcus faecium ; }, abstract = {Treatment of tannery effluent (TE) using bacterial biofilm is a trending approach in the current scenario, due to greater survival and adaptation in stress conditions. The present study is concerned with the characterization of biofilm-forming bacterium Enterococcus faecium from tannery sludge and the investigation of their activity under different physiological conditions. Biofilm formation by E. faecium was strongly affected by variable physiological conditions. The optimum conditions were pH 7.5, temperature 28 °C, incubation time up to 96 h, glucose 1%, yeast extract 0.1-0.5%, NaCl 0.1-0.5%, tannery effluent-TE up to 50% v/v and Cd, Cr (VI) and Ni from 0.25 to 0.5 mM. Further, E. faecium treated TE was less phytotoxic on the fenugreek plant than the TE treated by non-biofilm forming isolate. The toxicity of TE could be reduced by the potentially biofilm-forming bacteria, which may be used in the bioremediation process.}, } @article {pmid34311380, year = {2021}, author = {Guo, J and Yang, G and Zhuang, Z and Mai, Q and Zhuang, L}, title = {Redox potential-induced regulation of extracellular polymeric substances in an electroactive mixed community biofilm.}, journal = {The Science of the total environment}, volume = {797}, number = {}, pages = {149207}, doi = {10.1016/j.scitotenv.2021.149207}, pmid = {34311380}, issn = {1879-1026}, mesh = {*Biofilms ; Electrodes ; Electron Transport ; *Extracellular Polymeric Substance Matrix ; Oxidation-Reduction ; }, abstract = {Electroactive biofilms are promising in achieving efficient wastewater treatment and energy conversion in bioelectrochemical systems (BESs). Extracellular polymeric substances (EPS) are important for physical contact with electrode surface and extracellular electron transfer (EET) within biofilm. Redox potential is an important trigger for the regulation of EPS in microbial aggregates, but this yet is lacking for electroactive mixed community biofilms. This study first explored how redox potential affected EPS of electroactive mixed community biofilms, which were cultured in BES reactors with different anode potentials (-0.3 V, 0 V, +0.3 V, +0.6 V vs. SCE) using artificial brewery wastewater as substrate. The anode potential regulated biocurrent generation, overall EPS production, EPS composition and EPS redox properties. The biofilms poised at 0 V exhibited the highest current production (7.2 mA) and EPS redox capacity, while the +0.6 V biofilms had the lowest current production (1.2 mA) with lowest EPS redox capacity. The steady-state current exhibited a significant positive correlation with EPS redox capability, suggesting an important role of EPS in anode potential-dependent current production. Significant positive correlations between proteins or humic substances in EPS and EPS redox properties further verified that EPS redox feature raised from proteins and humic substances. This study provided a potential mechanism that anode potential determined the electroactivity of anode biofilm via regulating EPS composition and redox properties, and will facilitate the use of electroactive biofilms in bioelectrochemical applications.}, } @article {pmid34310795, year = {2022}, author = {Teves, A and Blanco, D and Casaretto, M and Torres, J and Alvarado, DE and Coaguila-Llerena, H and Faria, G and Jaramillo, DE}, title = {Multispecies biofilm removal by XP-endo Finisher and passive ultrasonic irrigation: A scanning electron microscopy study.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {48}, number = {1}, pages = {91-97}, doi = {10.1111/aej.12549}, pmid = {34310795}, issn = {1747-4477}, support = {18/24662-6//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity/microbiology ; Microscopy, Electron, Scanning ; *Root Canal Irrigants/therapeutic use ; Sodium Hypochlorite/therapeutic use ; Therapeutic Irrigation/methods ; Ultrasonics ; Water ; }, abstract = {The aim was to assess the effect of XP-endo Finisher (XPF) on multispecies biofilm removal, in comparison with passive ultrasonic irrigation (PUI) and conventional syringe irrigation (CSI), by scanning electron microscope (SEM). Fifty mandibular first premolars were instrumented, longitudinally sectioned. The split halves were incubated for 4 days with a broth obtained from three bacteria strains: Enterococcus faecalis, Eikenella corrodens and Streptococcus anginosus. Subsequently, the re-approximated split halves were irrigated with 4% sodium hypochlorite (NaOCl) or water using CSI, and the final irrigation protocols were CSI with 4% NaOCl (CSI+4%NaOCl), PUI+4%NaOCl, XPF+4%NaOCl and CSI+water. The analysis of biofilm removal was performed using SEM images. There were no differences between PUI and XPF (P > 0.05), and both groups promoted higher biofilm removal than CSI+4%NaOCl and CSI+water groups (P < 0.05). It can be concluded the multispecies biofilm removal was significantly improved using XPF and PUI when compared to CSI.}, } @article {pmid34310732, year = {2021}, author = {Liu, H and Xiao, M and Zuo, J and He, X and Lu, P and Li, Y and Zhao, Y and Xia, F}, title = {Vanillic acid combats Vibrio alginolyticus by cell membrane damage and biofilm reduction.}, journal = {Journal of fish diseases}, volume = {44}, number = {11}, pages = {1799-1809}, doi = {10.1111/jfd.13498}, pmid = {34310732}, issn = {1365-2761}, support = {2020NY-121//Department of Science and Technology of Shaanxi Province/ ; 2021NY-164//Department of Science and Technology of Shaanxi Province/ ; 32070129//National Natural Science Foundation of China/ ; 31800328//National Natural Science Foundation of China/ ; 31801513//National Natural Science Foundation of China/ ; 201937/WT_/Wellcome Trust/United Kingdom ; 201940/WT_/Wellcome Trust/United Kingdom ; BJ12-24//Shaanxi University of Science and Technology Doctoral Startup Fund/ ; 201937/WT_/Wellcome Trust/United Kingdom ; 201940/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cell Membrane/*drug effects ; Cell Membrane Permeability ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Vanillic Acid/*pharmacology ; Vibrio alginolyticus/*drug effects/ultrastructure ; Virulence ; }, abstract = {Antibiotics are the most powerful weapon against bacterial infectious diseases in aquaculture. However, the indiscriminate usage of antibiotics often culminates in the emerging development of antibiotic-resistant bacteria, making it imperative to search for novel types of antimicrobial agents. This study investigated the antibacterial and antivirulence effects of vanillic acid (VA) against the fish pathogen, Vibrio alginolyticus. We showed that VA had a good anti-Vibrio activity with minimal inhibitory concentration (MIC) of 1.0 mg/ml. In addition, VA wielded its antibacterial action in a dose-/time-dependent manner by causing cell membrane damage and increasing membrane permeability, which is evidenced by increasing the conductivity and malondialdehyde content in the treated cell cultures and the scanning electron microscopy images. Furthermore, VA significantly reduced the biofilm-forming capability, mobility and exotoxin production (protease and exopolysaccharide) and downregulation of the expression of biofilm- and virulence-associated genes (sypG, fliS, fliK, lafA, lafK, asp and luxR) was seen in the V. alginolyticus that exposed to VA at subinhibitory concentrations. Overall, our findings suggested that VA may be of interest for treating V. alginolyticus-associated infections in aquaculture.}, } @article {pmid34309796, year = {2021}, author = {Xu, Q and Hu, X and Wang, Y}, title = {Alternatives to Conventional Antibiotic Therapy: Potential Therapeutic Strategies of Combating Antimicrobial-Resistance and Biofilm-Related Infections.}, journal = {Molecular biotechnology}, volume = {63}, number = {12}, pages = {1103-1124}, pmid = {34309796}, issn = {1559-0305}, support = {51903176//National Natural Science Foundation of China/ ; No. 2019HXFH006//Clinical Research Incubation Project/ ; No. HXHL19003//Special Fund for Nursing Discipline Development/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Antimicrobial Peptides/pharmacology/therapeutic use ; Bacteria/drug effects/*metabolism ; Bacterial Infections/microbiology/*therapy ; Biofilms/drug effects ; Drug Resistance, Bacterial/drug effects ; Extracellular Polymeric Substance Matrix/drug effects/*metabolism ; Humans ; Metal Nanoparticles/therapeutic use ; Phage Therapy ; Quaternary Ammonium Compounds/pharmacology/therapeutic use ; }, abstract = {Antibiotics have been denoted as the orthodox therapeutic agents for fighting bacteria-related infections in clinical practices for decades. Nevertheless, overuse of antibiotics has led to the upsurge of species with antimicrobial resistance (AMR) or multi-drug resistance. Bacteria can also grow into the biofilm, which accounts for at least two-thirds of infections. Distinct gene expression and self-produced heterogeneous hydrated extracellular polymeric substance matrix architecture of biofilm contribute to their tolerance and externally manifest as antibiotic resistance. In this review, the difficulties in combating biofilm formation and AMR are introduced, and novel alternatives to antibiotics such as metal nanoparticles and quaternary ammonium compounds, chitosan and its derivatives, antimicrobial peptides, stimuli-responsive materials, phage therapy and other therapeutic strategies, from compounds to hydrogel, from inorganic to biological, are discussed. We expect to provide useful information for the readers who are seeking for solutions to the problem of AMR and biofilm-related infections.}, } @article {pmid34308485, year = {2021}, author = {Hu, S and Wang, X and Tan, Y and Liu, J and Zhao, H}, title = {'Chain and running' induced by mechanical interactions among cells of different phenotypes in the Bacillus subtilis biofilm.}, journal = {European biophysics journal : EBJ}, volume = {50}, number = {7}, pages = {1013-1023}, pmid = {34308485}, issn = {1432-1017}, support = {11772047//National Natural Science Foundation of China/ ; 11972074//National Natural Science Foundation of China/ ; 11620101001//Key International collaborating project from National Natural Science Foundation of China/ ; }, mesh = {*Bacillus subtilis ; Biofilms ; Phenotype ; *Running ; }, abstract = {In either a living system or a non-living system, the interaction among its constituent cells or particles is a fundamental aspect at all scales. For example, during the Bacillus subtilis biofilm formation, cells differentiate into multiple phenotypes to adapt to the environments; few hours after the initial inoculation, we find the phenotype of matrix-producing cells form "chain" structure surrounding the phenotype of the "running" motile cells. We use "chain" to characterize the structure of matrix-producing cells, and "running" to characterize the proliferation and growth of motile cells. Due to a large number of cells in the biofilm, it is impossible to construct a traditional kinetic model to describe the causal link between the single-cell movement and the colony behavior. Here, we obtain cell state information and cell group shape information through experiments; after the image analysis, we get the key interaction rules between cells, and then, we simulate the comparable movement of two cell types and the resulting colony geometry using the multi-agent model. Our work makes a better understanding of the relationship between the macroscopic shape of colonies and microscopic mechanical interactions among cells in the early stage of biofilm growth.}, } @article {pmid34308271, year = {2020}, author = {Carabelli, AM and Isgró, M and Sanni, O and Figueredo, GP and Winkler, DA and Burroughs, L and Blok, AJ and Dubern, JF and Pappalardo, F and Hook, AL and Williams, P and Alexander, MR}, title = {Single-Cell Tracking on Polymer Microarrays Reveals the Impact of Surface Chemistry on Pseudomonas aeruginosa Twitching Speed and Biofilm Development.}, journal = {ACS applied bio materials}, volume = {3}, number = {12}, pages = {8471-8480}, pmid = {34308271}, issn = {2576-6422}, support = {103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; }, abstract = {Bacterial biofilms exhibit up to 1000 times greater resistance to antibiotic or host immune clearance than planktonic cells. Pseudomonas aeruginosa produces retractable type IV pili (T4P) that facilitate twitching motility on surfaces. The deployment of pili is one of the first responses of bacteria to surface interactions and because of their ability to contribute to cell surface adhesion and biofilm formation, this has relevance to medical device-associated infections. While polymer chemistry is known to influence biofilm development, its impact on twitching motility is not understood. Here, we combine a polymer microarray format with time-lapse automated microscopy to simultaneously assess P. aeruginosa twitching motility on 30 different methacrylate/acrylate polymers over 60 min post inoculation using a high-throughput system. During this critical initial period where the decision to form a biofilm is thought to occur, similar numbers of bacterial cells accumulate on each polymer. Twitching motility is observed on all polymers irrespective of their chemistry and physical surface properties, in contrast to the differential biofilm formation noted after 24 h of incubation. However, on the microarray polymers, P. aeruginosa cells twitch at significantly different speeds, ranging from 5 to ∼13 nm/s, associated with crawling or walking and are distinguishable from the different cell surface tilt angles observed. Chemometric analysis using partial least-squares (PLS) regression identifies correlations between surface chemistry, as measured by time-of-flight secondary ion mass spectrometry (ToF-SIMS), and both biofilm formation and single-cell twitching speed. The relationships between surface chemistry and these two responses are different for each process. There is no correlation between polymer surface stiffness and roughness as determined by atomic force measurement (AFM), or water contact angle (WCA), and twitching speed or biofilm formation. This reinforces the dominant and distinct contributions of material surface chemistry to twitching speed and biofilm formation.}, } @article {pmid34307072, year = {2021}, author = {Renye, JA and Steinberg, DH}, title = {Thermophilin 110 inhibits growth and biofilm formation of Streptococcus mutans.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {31}, number = {}, pages = {e00647}, pmid = {34307072}, issn = {2215-017X}, abstract = {Dental caries continues to occur in both children and adults worldwide resulting in significant economic burden, and consumers have expressed interest in natural products that can prevent these recurrent infections. In this study, S. thermophilus B59671, which produces thermophilin 110, was shown to inhibit the growth of S. mutans UA159. A thermophilin concentration ≥ 80 AU ml[-1] prevented the growth of S. mutans UA159 in batch culture, while ≥ 160 AU ml[-1] was required to prevent biofilm growth. Co-culturing S. thermophilus B59671 and S. mutans UA159 also resulted in impaired biofilm growth. Thermophillin 110 was also shown inhibit additional S. mutans strains and commensal oral streptococci at higher concentrations (640-1280 AU ml[-1]). These results suggest that thermophilin 110 could be used as a natural antimicrobial in oral care products and support the need for additional studies to assess the probiotic potential of S. thermophilus B59671.}, } @article {pmid34306846, year = {2021}, author = {Rozis, M and Evangelopoulos, DS and Pneumaticos, SG}, title = {Orthopedic Implant-Related Biofilm Pathophysiology: A Review of the Literature.}, journal = {Cureus}, volume = {13}, number = {6}, pages = {e15634}, pmid = {34306846}, issn = {2168-8184}, abstract = {Orthopedic implant-related infections remain a major problem even nowadays. Bacterial resistance through biofilm formation, in addition to the limited treatment options available, has resulted in an increased effort to better understand pathophysiology mechanisms. We performed a review of the literature in order to identify major biofilm formation pathways through which possible treatment strategies could arise.}, } @article {pmid34304662, year = {2021}, author = {Figueiredo, CM and Malvezzi Karwowski, MS and da Silva Ramos, RCP and de Oliveira, NS and Peña, LC and Carneiro, E and Freitas de Macedo, RE and Rosa, EAR}, title = {Bacteriophages as tools for biofilm biocontrol in different fields.}, journal = {Biofouling}, volume = {37}, number = {6}, pages = {689-709}, doi = {10.1080/08927014.2021.1955866}, pmid = {34304662}, issn = {1029-2454}, mesh = {*Bacteriophages ; Biofilms ; }, abstract = {Microbial biofilms are difficult to control due to the limited accessibility that antimicrobial drugs and chemicals have to the entrapped inner cells. The extracellular matrix, binds water, contributes to altered cell physiology within biofilms and act as a barrier for most antiproliferative molecules. Thus, new strategies need to be developed to overcome biofilm vitality. In this review, based on 223 documents, the advantages, recommendations, and limitations of using bacteriophages as 'biofilm predators' are presented. The plausibility of using phages (bacteriophages and mycoviruses) to control biofilms grown in different environments is also discussed. The topics covered here include recent historical experiences in biofilm control/eradication using phages in medicine, dentistry, veterinary, and food industries, the pros and cons of their use, and the development of microbial resistance/immunity to such viruses.}, } @article {pmid34303315, year = {2022}, author = {Widyarman, AS and Theodorea, CF}, title = {Novel Indigenous Probiotic Lactobacillus reuteri Strain Produces Anti-biofilm Reuterin against Pathogenic Periodontal Bacteria.}, journal = {European journal of dentistry}, volume = {16}, number = {1}, pages = {96-101}, pmid = {34303315}, issn = {1305-7456}, abstract = {OBJECTIVE: The aim of this study was to evaluate the effect of reuterin produced by a novel probiotic strain of Lactobacillus reuteri against periodontal biofilms.

MATERIALS AND METHODS:  L. reuteri LC382415 (an indigenous Indonesian strain) was cultured in Man, Rogosa, and Sharpe (MRS) agar in anaerobic conditions for 24 hours. To isolate reuterin, L. reuteri was suspended in 300-mM glycerol in MRS broth and incubated under anaerobic conditions for 3 hours, and the supernatant fraction was filtered. The presence of reuterin was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and its concentration was determined. The effect of reuterin on Porphyromonas gingivalis ATCC 33277 and T. denticola ATCC 35405 biofilms was evaluated using biofilm assays. Biofilms were formed by incubating bacteria in 96-well microplates for 48 hours. A dose-dependent experiment was performed with reuterin concentrations of 12.5, 25, 50, and 100 μg/mL on biofilms. The inhibitory effect was measured at 1, 3, 6, and 24 hours. The biofilm masses were measured at 490 nm. Statistical analysis was using one-way ANOVA.

RESULTS:  The SDS-PAGE assay confirmed the presence of reuterin (52 kDa) in the culture supernatant of the L. reuteri strain. Reuterin in a concentration as low as 12.5 μg/mL significantly inhibited single- and mixed-species biofilms (p < 0.05).

CONCLUSIONS:  This is the first study to demonstrate the promising effect of reuterin isolated from L. reuteri LC382415 against periodontal bacteria. Further studies are warranted to explore the mechanism of this active component.}, } @article {pmid34302932, year = {2021}, author = {Jiang, Q and Yu, Y and Xu, R and Zhang, Z and Liang, C and Sun, H and Deng, F and Yu, X}, title = {The temporal shift of peri-implant microbiota during the biofilm formation and maturation in a canine model.}, journal = {Microbial pathogenesis}, volume = {158}, number = {}, pages = {105100}, doi = {10.1016/j.micpath.2021.105100}, pmid = {34302932}, issn = {1096-1208}, mesh = {Animals ; Biofilms ; Clostridiales ; *Dental Implants ; Dogs ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; }, abstract = {OBJECTIVES: Although the mature peri-implant biofilm composition is well studied, there is very little information on the succession of in vivo dental implant colonization. The aim of this study was to characterize the temporal changes and diversity of peri-implant supra-mucosal and sub-mucosal microbiota during the process of the plaque maturation.

MATERIALS AND METHODS: Dental implants (n = 25) were placed in the mandible of 3 beagle dogs. Illumina MiSeq sequencing of the hypervariable V3-V4 region of the 16S rRNA gene amplicons was used to characterize the supra/sub-mucosal microbiota in the peri-implant niches at 1day (T1), 7days (T2), 14days (T3), 21days (T4) and 28days (T5) after Phase Ⅱ surgery of the healing abutment placement. QIIME, Mothur, LEfSe and R-package were used for downstream analysis.

RESULTS: A total of 1184 operational taxonomic units (OTUs), assigned into 22 phyla, 264 genera and 339 species were identified. In supra-mucosal niches, the alpha parameters of shannon, sobs and chao1 displayed significant differences between T1 and other time-points. However, in sub-mucosal niches, only sobs, chao1, and ace indexes displayed significant differences between T1 and T3, and T1 and T5. Beta-diversity showed statistically significant difference between T1 and T2, T3, T4, T5 within both sub-mucosal and supra-mucosal plaque. The phyla Bacteroidetes, Proteobacteria and Firmicutes were the most dominant phyla of both sub-mucosal and supra-mucosal niches at all time-points and Firmicutes increased during the maturation of peri-implant plaque. At the genus level, Neisseria decreased significantly after T1 suggesting the establishment of an anaerobic microenvironment. A decrease of Porphyromonas during the formation of sub-mucosal microbial community was also detected. Co-occurrence network analysis exhibited a more complicated co-occurrence relationship of bacterial species in the sub-mucosal niches. Fusobacterium nucleatum, Filifactor villosus, and some other species may play a crucial role in biofilm maturation.

CONCLUSIONS: The present results suggested that the development of peri-implant biofilm followed a similar pattern to dental plaque formation. Sub-mucosal biofilm may go through a more complicated procedure of maturation than supra-mucosal biofilm.}, } @article {pmid34300720, year = {2021}, author = {Berta, GN and Romano, F and Vallone, R and Abbadessa, G and Di Scipio, F and Defabianis, P}, title = {An Innovative Strategy for Oral Biofilm Control in Early Childhood Based on a Resveratrol-Cyclodextrin Nanotechnology Approach.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {14}, pages = {}, pmid = {34300720}, issn = {1996-1944}, abstract = {The purpose of this randomized controlled study was to evaluate the clinical efficacy of a novel oral spray containing resveratrol (RV) in controlling bacterial biofilm and gingival inflammation in early childhood. RV, a natural polyphenol, known for its anti-inflammatory and anti-infective activities, was included in a nanovector of 2-hydroxypropyl-beta-cyclodextrins (HPβCD) to improve its bioavailability. A total of 64 children between two and five years of age with plaque-induced gingivitis were randomly included in two equal groups. Both groups were enrolled in a mechanical plaque control program for a period of four weeks, while the test group was also instructed to use the RV-HPβCD mouthwash (in spray formulation) once daily, after toothbrushing. All children underwent three oral hygiene motivation sessions, 14 days apart, during which the full-mouth presence of bacterial plaque, gingival inflammation, dental stain and salivary pH were recorded. At two-week appointment, they also received professional plaque removal. The use of RV-based oral spray significantly reduced the amount of dental plaque and the percentage of bleeding sites and improved salivary pH compared to the control group at both two- and four-week examinations. Based on these promising results, the local delivery of RV-HPβCD via oral spray could enhance the control of dental biofilm in early childhood, when antiseptic mouthwashes are not recommended.}, } @article {pmid34300053, year = {2021}, author = {Idrees, M and Sawant, S and Karodia, N and Rahman, A}, title = {Staphylococcus aureus Biofilm: Morphology, Genetics, Pathogenesis and Treatment Strategies.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {14}, pages = {}, pmid = {34300053}, issn = {1660-4601}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; *Staphylococcus aureus/genetics ; }, abstract = {Staphylococcus aureus is a nosocomial bacterium causing different infectious diseases, ranging from skin and soft tissue infections to more serious and life-threatening infections such as septicaemia. S. aureus forms a complex structure of extracellular polymeric biofilm that provides a fully secured and functional environment for the formation of microcolonies, their sustenance and recolonization of sessile cells after its dispersal. Staphylococcus aureus biofilm protects the cells against hostile conditions, i.e., changes in temperature, limitations or deprivation of nutrients and dehydration, and, more importantly, protects the cells against antibacterial drugs. Drugs are increasingly becoming partially or fully inactive against S. aureus as they are either less penetrable or totally impenetrable due to the presence of biofilms surrounding the bacterial cells. Other factors, such as evasion of innate host immune system, genome plasticity and adaptability through gene evolution and exchange of genetic material, also contribute to the ineffectiveness of antibacterial drugs. This increasing tolerance to antibiotics has contributed to the emergence and rise of antimicrobial resistance (AMR), a serious problem that has resulted in increased morbidity and mortality of human and animal populations globally, in addition to causing huge financial losses to the global economy. The purpose of this review is to highlight different aspects of S. aureus biofilm formation and its overall architecture, individual biofilm constituents, clinical implications and role in pathogenesis and drug resistance. The review also discusses different techniques used in the qualitative and quantitative investigation of S. aureus biofilm and various strategies that can be employed to inhibit and eradicate S. aureus biofilm.}, } @article {pmid34299385, year = {2021}, author = {Abo-Salem, HM and Abd El Salam, HA and Abdel-Aziem, AM and Abdel-Aziz, MS and El-Sawy, ER}, title = {Synthesis, Molecular Docking, and Biofilm Formation Inhibitory Activity of Bis(Indolyl)Pyridines Analogues of the Marine Alkaloid Nortopsentin.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {14}, pages = {}, pmid = {34299385}, issn = {1420-3049}, mesh = {Alkaloids/*chemistry ; Anti-Bacterial Agents/*chemical synthesis/*pharmacology ; Bacteria/*drug effects ; Biofilms/drug effects/*growth & development ; DNA Gyrase/chemistry ; DNA Topoisomerase IV/antagonists & inhibitors ; Enzyme Inhibitors/chemistry/*pharmacology ; Indoles/*chemistry ; Molecular Docking Simulation ; Nucleoside-Phosphate Kinase/antagonists & inhibitors ; Pyridines/chemistry ; }, abstract = {An efficient and simple protocol for the synthesis of a new class of diverse bis(indolyl)pyridines analogues of the marine alkaloid nortopsentin has been reported. A one-pot four-component condensation of 3-cyanocarbomethylindole, various aldehyde, 3-acetylindole, and ammonium acetate in glacial acetic acid led to the formation of 2,6-bis(1H-indol-3-yl)-4-(substituted-phenyl)pyridine-5-carbonitriles. Additionally, 2,6-bis(1H-indol-3-yl)-4-(benzofuran) pyridine-5-carbonitriles were prepared via a one-pot four-component condensation of 3-cyanocarbomethylindole, various N-substituted-indole-3-aldehydes, 2-acetylbenzofuran, and ammonium acetate. The synthesized compounds were evaluated for their ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 6538 and the Gram-negative strain Escherichia coli ATCC 25922. Some of the new compounds showed a marked selectivity against the Gram-positive and Gram-negative strains. Remarkably, five compounds 4b, 7a, 7c, 7d and 8e demonstrated good antibiofilm formation against S. aureus and E. coli. On the other hand, the release of reducing sugars and proteins from the treated bacterial strains over the untreated strains was considered to explain the disruption effect of the selected compound on the contact cells of S. aureus and E. coli. Out of all studied compounds, the binding energies and binding mode of bis-indole derivatives 7c and 7d were theoretically the best thymidylate kinase, DNA gyrase B and DNA topoisomerase IV subunit B inhibitors.}, } @article {pmid34299216, year = {2021}, author = {Liu, Z and Li, L and Fang, Z and Lee, Y and Zhao, J and Zhang, H and Chen, W and Li, H and Lu, W}, title = {Integration of Transcriptome and Metabolome Reveals the Genes and Metabolites Involved in Bifidobacterium bifidum Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {22}, number = {14}, pages = {}, pmid = {34299216}, issn = {1422-0067}, support = {31871774//the National Nature Science Foundation of China/ ; 31820103010//the National Nature Science Foundation of China/ ; JUSRP51903B//the Fundamental Research Funds for the Central Universities/ ; BP0719028//111project/ ; none//International Cooperation Fund Pool Project of Jiangsu Industrial Technology Research Institute/ ; JUFSTR20180102//the collaborative innovation center of food safety and quality control in Jiangsu Province and the National First-class Discipline Program of Food Science and Technology/ ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Bifidobacterium bifidum/genetics/metabolism/*physiology ; Biofilms/*growth & development ; Gene Expression Profiling ; Metabolome ; Quorum Sensing ; Transcriptome ; Triticum/microbiology ; }, abstract = {Bifidobacterium bifidum strains, an important component of probiotic foods, can form biofilms on abiotic surfaces, leading to increased self-resistance. However, little is known about the molecular mechanism of B. bifidum biofilm formation. A time series transcriptome sequencing and untargeted metabolomics analysis of both B. bifidum biofilm and planktonic cells was performed to identify key genes and metabolites involved in biofilm formation. Two hundred thirty-five nonredundant differentially expressed genes (DEGs) (including vanY, pstS, degP, groS, infC, groL, yajC, tadB and sigA) and 219 nonredundant differentially expressed metabolites (including L-threonine, L-cystine, L-tyrosine, ascorbic acid, niacinamide, butyric acid and sphinganine) were identified. Thirteen pathways were identified during the integration of both transcriptomics and metabolomics data, including ABC transporters; quorum sensing; two-component system; oxidative phosphorylation; cysteine and methionine metabolism; glutathione metabolism; glycine, serine and threonine metabolism; and valine, leucine and isoleucine biosynthesis. The DEGs that relate to the integration pathways included asd, atpB, degP, folC, ilvE, metC, pheA, pstS, pyrE, serB, ulaE, yajC and zwf. The differentially accumulated metabolites included L-cystine, L-serine, L-threonine, L-tyrosine, methylmalonate, monodehydroascorbate, nicotinamide, orthophosphate, spermine and tocopherol. These results indicate that quorum sensing, two-component system and amino acid metabolism are essential during B. bifidum biofilm formation.}, } @article {pmid34298964, year = {2021}, author = {Yu, TT and Kuppusamy, R and Yasir, M and Hassan, MM and Sara, M and Ho, J and Willcox, MDP and Black, DS and Kumar, N}, title = {Polyphenylglyoxamide-Based Amphiphilic Small Molecular Peptidomimetics as Antibacterial Agents with Anti-Biofilm Activity.}, journal = {International journal of molecular sciences}, volume = {22}, number = {14}, pages = {}, pmid = {34298964}, issn = {1422-0067}, support = {DP180100845//Australian Research Council/ ; }, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Escherichia coli/*physiology ; *Peptidomimetics/chemical synthesis/chemistry/pharmacology ; Staphylococcus aureus/*physiology ; Structure-Activity Relationship ; Sulfonylurea Compounds/chemical synthesis/chemistry/pharmacology ; }, abstract = {The rapid emergence of drug-resistant bacteria is a major global health concern. Antimicrobial peptides (AMPs) and peptidomimetics have arisen as a new class of antibacterial agents in recent years in an attempt to overcome antibiotic resistance. A library of phenylglyoxamide-based small molecular peptidomimetics was synthesised by incorporating an N-alkylsulfonyl hydrophobic group with varying alkyl chain lengths and a hydrophilic cationic group into a glyoxamide core appended to phenyl ring systems. The quaternary ammonium iodide salts 16d and 17c showed excellent minimum inhibitory concentration (MIC) of 4 and 8 μM (2.9 and 5.6 μg/mL) against Staphylococcus aureus, respectively, while the guanidinium hydrochloride salt 34a showed an MIC of 16 μM (8.5 μg/mL) against Escherichia coli. Additionally, the quaternary ammonium iodide salt 17c inhibited 70% S. aureus biofilm formation at 16 μM. It also disrupted 44% of pre-established S. aureus biofilms at 32 μM and 28% of pre-established E. coli biofilms 64 μM, respectively. A cytoplasmic membrane permeability study indicated that the synthesised peptidomimetics acted via disruption and depolarisation of membranes. Moreover, the quaternary ammonium iodide salts 16d and 17c were non-toxic against human cells at their therapeutic dosages against S. aureus.}, } @article {pmid34296696, year = {2021}, author = {Ding, Y and Chen, Y and Zhuang, M and Xu, J and Jiang, X}, title = {[Study on inhibitory effect of Ag[+]-loaded TiO2 on the biofilm of Staphylococcus aureus].}, journal = {Zhonghua wei zhong bing ji jiu yi xue}, volume = {33}, number = {6}, pages = {736-739}, doi = {10.3760/cma.j.cn121430-20200518-00390}, pmid = {34296696}, issn = {2095-4352}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Microbial Sensitivity Tests ; *Silver/pharmacology ; *Staphylococcus aureus ; Titanium ; }, abstract = {OBJECTIVE: To observe the antibacterial effect of Ag[+]-loaded TiO2 (Ag-TiO2) and Ag-TiO2 coated endotracheal tube (ETT) on the bacterial biofilm (BF) of Staphylococcus aureus.

METHODS: 2, 3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) colorimetric method was used to detect minimal inhibitory concertation (MIC) of Ag-TiO2 for inhibition of BF of Staphylococcus aureus. The Ag-TiO2 coated ETT were prepared, and divided into 11 mg/L, 8 mg/L, 5 mg/L, 2 mg/L and 0 mg/L ETT group, according to the concentration gradient, then impregnated in the liquid with Staphylococcus aureus at a concentration of 1.0×10[9] cfu/L. The influence of antibacterial coated ETT on the formation of Staphylococcus aureus BF was determined by detecting the colonies of bacteria and BF on the ETT.

RESULTS: Ag-TiO2 had a significant inhibitory effect on Staphylococcus aureus BF in a concentration-dependent manner, and its MIC was 10 mg/L. Ag-TiO2 coated ETT has significant anti-Staphylococcus aureus BF effect, and the higher the concentration, the stronger the effect. The absorbance (A) values of Ag-TiO2 5 mg/L, 8 mg/L, 11 mg/L ETT groups were significantly lower than that in control group (0.176±0.004, 0.147±0.002, 0.094±0.002 vs. 0.267±0.045, all P < 0.05). The inhibitory rates of Ag-TiO2 2 mg/L, 5 mg/L, 8 mg/L ETT groups were increased gradually, and 11 mg/L Ag-TiO2 coated ETT group had the highest inhibitory rate for BF, the inhibitory rates were 6.4%, 34.1%, 44.9% and 64.8%, respectively.

CONCLUSIONS: Both Ag-TiO2 and Ag-TiO2 coated ETT have significant inhibitory effects on Staphylococcus aureus BF.}, } @article {pmid34296201, year = {2021}, author = {Wang, Y and Jaggers, RM and Mar, P and Galley, JD and Shaffer, T and Rajab, A and Deshpande, S and Mashburn-Warren, L and Buzzo, JR and Goodman, SD and Bailey, MT and Besner, GE}, title = {Lactobacillus reuteri in its biofilm state promotes neurodevelopment after experimental necrotizing enterocolitis in rats.}, journal = {Brain, behavior, & immunity - health}, volume = {14}, number = {}, pages = {}, pmid = {34296201}, issn = {2666-3546}, support = {R01 GM123482/GM/NIGMS NIH HHS/United States ; }, abstract = {Necrotizing enterocolitis (NEC) is a devastating disease affecting premature newborns with no known cure. Up to half of survivors subsequently exhibit cognitive impairment and neurodevelopmental defects. We created a novel probiotics delivery system in which the probiotic Lactobacillus reuteri (Lr) was induced to form a biofilm [Lr (biofilm)] by incubation with dextranomer microspheres loaded with maltose (Lr-DM-maltose). We have previously demonstrated that a single dose of the probiotic Lr administered in its biofilm state significantly reduces the incidence of NEC and decreases inflammatory cytokine production in an animal model of the disease. The aim of our current study was to determine whether a single dose of the probiotic Lr administered in its biofilm state protects the brain after experimental NEC. We found that rat pups exposed to NEC reached developmental milestones significantly slower than breast fed pups, with mild improvement with Lr (biofilm) treatment. Exposure to NEC had a negative effect on cognitive behavior, which was prevented by Lr (biofilm) treatment. Lr administration also reduced anxiety-like behavior in NEC-exposed rats. The behavioral effects of NEC were associated with increased numbers of activated microglia, decreased myelin basic protein (MBP), and decreased neurotrophic gene expression, which were prevented by administration of Lr (biofilm). Our data indicate early enteral treatment with Lr in its biofilm state prevented the deleterious effects of NEC on developmental impairments.}, } @article {pmid34295158, year = {2021}, author = {Xu, J and Li, Y and Wang, H and Zhu, M and Feng, W and Liang, G}, title = {Enhanced Antibacterial and Anti-Biofilm Activities of Antimicrobial Peptides Modified Silver Nanoparticles.}, journal = {International journal of nanomedicine}, volume = {16}, number = {}, pages = {4831-4846}, pmid = {34295158}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Peptides ; Pore Forming Cytotoxic Proteins ; Silver ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus ; }, abstract = {BACKGROUND: The biofilms could protect bacteria from antibiotics and promote the production of drug-resistant strains, making the bacteria more difficult to be eradicated. Thus, we developed an AMP@PDA@AgNPs nanocomposite, which is formed by modifying silver nanoparticles (AgNPs) with antimicrobial peptides (AMP) modified nanocomposite to destroy biofilm in this study.

METHODS: The AMP@PDA@AgNPs nanocomposite was prepared with polymerization method and characterized by using ultraviolet-visible (UV-vis) spectroscopy, dynamic light scattering (DLS), Fourier transform-infrared spectroscopy (FT-IR), and transmission electron microscope (TEM). The antibacterial effects of the nanocomposite were investigated by using agar diffusion method and minimum inhibitory concentration (MIC) test. The quantitative analysis of the biofilm formation by the nanocomposite was conducted using crystal violet staining and confocal laser scanning microscope (CLSM).

RESULTS: The DLS and TEM analysis showed it was a spherical nanocomposite with 200 nm size and well dispersed . The results of UV-vis and FT-IR confirmed the presence of AMP and AgNPs. The nanocomposite had an excellent biocompatibility at 100 μg/mL. And the AMP@PDA@AgNPs nanocomposite showed superior antimicrobial activity against both Gram-negative (E. coli, P. aeruginosa) and Gram-positive (S. aureus) bacteria than AgNPs or AMP. Importantly, the mRNA expression of biofilm-related genes were decreased under the action of the nanocomposites.

CONCLUSION: An AMP@PDA@AgNPs nanocomposite with good biocompatibility was successfully prepared. The nanocomposite could destruct bacterial biofilms by inhibiting the expression of biofilm-related genes. The synergistic strategy of AMPs and AgNPs could provide a new perspective for the treatment of bacterial infection.}, } @article {pmid34294980, year = {2021}, author = {Abdullah, and Algburi, A and Asghar, A and Huang, Q and Mustfa, W and Javed, HU and Zehm, S and Chikindas, ML}, title = {Black cardamom essential oil prevents Escherichia coli O157:H7 and Salmonella Typhimurium JSG 1748 biofilm formation through inhibition of quorum sensing.}, journal = {Journal of food science and technology}, volume = {58}, number = {8}, pages = {3183-3191}, pmid = {34294980}, issn = {0022-1155}, abstract = {This study aimed to investigate the chemical composition, using GC-MS, and anti-biofilm potential of black cardamom essential oil (BCEO) against biofilms of Escherichia coli O157:H7 and Salmonella Typhimurium JSG 1748 through inhibition of bacterial quorum sensing. GC-MS quantification demonstrated that BCEO contains 1,8-cineole (44.24%), α-terpinyl acetate (12.25%), nerolidol (6.03%), and sabinene (5.96%) as the major bioactive compounds. Antioxidant assays for BCEO revealed the total phenolic and flavonoid mean values were 1325.03 ± 7.69 mg GAE 100/g and 168.25 ± 5.26 mg CE/g, respectively. In regards to antimicrobial potential, Candida albicans was the most sensitive species compared to Streptococcus mutans, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Salmonella Typhimurium with the following zones of inhibition; 14.4 ± 0.52, 13.2 ± 0.42, 11.2 ± 0.28, 11.0 ± 0.52, 8.2 ± 0.24 and 6.6 ± 0.18 mm in diameter, respectively. Biofilm inhibition by BCEO was concentration-dependent, when various concentrations of 0.03, 0.06, 0.12, 0.25 and 0.5% were applied, 33.67, 34.14, 38.66, 46.65 and 50.17% of Salmonella Typhimurium biofilm was inhibited, while 47.31, 54.15, 76.57, 83.36 and 84.63% of Escherichia coli biofilm formation was prevented. Chromobacterium violaceum ATCC 12,472 and its product violacein, was used as a microbial indicator for enhancement or inhibition of quorum sensing. Our data showed that 0.5% of BCEO inhibited violacein production without influencing the growth of Chromobacterium violaceum, while 1% of BCEO, caused 100% inhibtion of violacein production together with 30% inhibition of growth. This study shows that BCEO possesses promising antioxidant and antimicrobial potential, and found anti-biofilm activities linked to the quenching of the quorum sensing system of E. coli and S. Typhimurium.}, } @article {pmid34294810, year = {2021}, author = {Verspecht, T and Van Holm, W and Boon, N and Bernaerts, K and Daep, CA and Zayed, N and Quirynen, M and Teughels, W}, title = {Comparison of the modulatory effects of three structurally similar potential prebiotic substrates on an in vitro multi-species oral biofilm.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {15033}, pmid = {34294810}, issn = {2045-2322}, mesh = {Biodiversity ; *Biofilms/drug effects/growth & development ; Host Microbial Interactions ; Metagenome ; Metagenomics/methods ; Microbiota ; Mouth/*microbiology ; Prebiotics/*administration & dosage ; Virulence/genetics ; }, abstract = {Previous research identified potential prebiotic substrates for oral health like the structural analogues N-acetyl-D-mannosamine (NADM) and N-acetyl-D-glucosamine (NADG). The main hypothesis of the current study was twofold. Firstly, it was hypothesized that the modulatory effects of NADM are not limited to changes in multi-species oral biofilm composition, but also include effects on metabolism, virulence, and inflammatory potential. Secondly, the presence and orientation of their N-acetyl group could play a role. Therefore, a comparison was made between the effects of NADM, NADG and D-(+)-mannose on multi-species oral biofilms. Besides a beneficial compositional shift, NADM-treated biofilms also showed an altered metabolism, a reduced virulence and a decreased inflammatory potential. At a substrate concentration of 1 M, these effects were pronounced for all biofilm aspects, whereas at ~ 0.05 M (1%(w/v)) only the effects on virulence were pronounced. When comparing between substrates, both the presence and orientation of the N-acetyl group played a role. However, this was generally only at 1 M and dependent on the biofilm aspect. Overall, NADM was found to have different effects at two concentrations that beneficially modulate in vitro multi-species oral biofilm composition, metabolism, virulence and inflammatory potential. The presence and orientation of the N-acetyl group influenced these effects.}, } @article {pmid34293645, year = {2021}, author = {Panyakorn, T and Makeudom, A and Kangvonkit, P and Pattamapun, K and Wanachantararak, P and Charumanee, S and Krisanaprakornkit, S}, title = {Efficacy of double antibiotics in hydroxypropyl methylcellulose for bactericidal activity against Enterococcus faecalis and Streptococcus gordonii in biofilm.}, journal = {Archives of oral biology}, volume = {129}, number = {}, pages = {105210}, doi = {10.1016/j.archoralbio.2021.105210}, pmid = {34293645}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Calcium Hydroxide ; Dental Pulp Cavity ; *Enterococcus faecalis ; Humans ; Hypromellose Derivatives ; Root Canal Irrigants ; *Streptococcus gordonii ; }, abstract = {OBJECTIVE: This study aimed to investigate the efficacy of double antibiotics, including ciprofloxacin and metronidazole, in a new vehicle, hydroxypropyl methylcellulose (HPMC), against Enterococcus faecalis and Streptococcus gordonii grown in biofilm.

DESIGN: Human mandibular premolars were prepared and divided into four groups: (i) negative control, (ii) positive control, (iii) infected with E. faecalis and S. gordonii for 21 days and intracanally medicated with double antibiotics in HPMC, and (iv) infected with E. faecalis and S. gordonii for 21 days and intracanally medicated with calcium hydroxide (UltraCal™). The efficacy of medication for 14 or 28 days was determined by bacterial cultures and RT-qPCR for absolute quantities of E. faecalis and S. gordonii cDNA and for relative mRNA expressions of pbp5 and gtfG genes.

RESULTS: There were significant decreases in the mean colony forming units and mean cDNA amounts of E. faecalis and S. gordonii in group (iii) on days 14 and 28 compared to those in group (ii) (p < 0.01). However, the mean cDNA amounts of E. faecalis and S. gordonii in group (iv) were found to be significantly increased on day 28 (p < 0.05). The mRNA expression of gtfG was significantly decreased in groups (iii) and (iv) on days 14 and 28, whereas that of pbp5 was significantly increased in group (iv) on days 14 and 28 (p < 0.01).

CONCLUSION: Double antibiotics in HPMC gel showed an in vitro efficacy against E. faecalis and S. gordonii grown in biofilm, suggesting its clinical application as an intracanal medicament for both primary and persistent infections.}, } @article {pmid34292966, year = {2021}, author = {Pulukkody, AC and Yung, YP and Donnarumma, F and Murray, KK and Carlson, RP and Hanley, L}, title = {Spatially resolved analysis of Pseudomonas aeruginosa biofilm proteomes measured by laser ablation sample transfer.}, journal = {PloS one}, volume = {16}, number = {7}, pages = {e0250911}, pmid = {34292966}, issn = {1932-6203}, support = {S10 RR025653/RR/NCRR NIH HHS/United States ; U01 EB019416/EB/NIBIB NIH HHS/United States ; }, mesh = {Bacterial Proteins/metabolism ; Biofilms/growth & development/*radiation effects ; Chromatography, High Pressure Liquid ; *Lasers, Solid-State ; Polycarboxylate Cement/chemistry ; Proteome/*analysis ; Proteomics/methods ; Pseudomonas aeruginosa/*metabolism/physiology ; Specimen Handling/instrumentation/*methods ; Tandem Mass Spectrometry ; }, abstract = {Heterogeneity in the distribution of nutrients and oxygen gradients during biofilm growth gives rise to changes in phenotype. There has been long term interest in identifying spatial differences during biofilm development including clues that identify chemical heterogeneity. Laser ablation sample transfer (LAST) allows site-specific sampling combined with label free proteomics to distinguish radially and axially resolved proteomes for Pseudomonas aeruginosa biofilms. Specifically, differential protein abundances on oxic vs. anoxic regions of a biofilm were observed by combining LAST with bottom up proteomics. This study reveals a more active metabolism in the anoxic region of the biofilm with respect to the oxic region for this clinical strain of P. aeruginosa, despite this organism being considered an aerobe by nature. Protein abundance data related to cellular acclimations to chemical gradients include identification of glucose catabolizing proteins, high abundance of proteins from arginine and polyamine metabolism, and proteins that could also support virulence and environmental stress mediation in the anoxic region. Finally, the LAST methodology requires only a few mm2 of biofilm area to identify hundreds of proteins.}, } @article {pmid34292941, year = {2021}, author = {Angeles-Martinez, L and Hatzimanikatis, V}, title = {The influence of the crowding assumptions in biofilm simulations.}, journal = {PLoS computational biology}, volume = {17}, number = {7}, pages = {e1009158}, pmid = {34292941}, issn = {1553-7358}, mesh = {*Biofilms ; Computational Biology/*methods ; Escherichia coli/physiology ; Microbial Interactions/*physiology ; Microbiota/*physiology ; *Models, Biological ; }, abstract = {Microorganisms are frequently organized into crowded structures that affect the nutrients diffusion. This reduction in metabolite diffusion could modify the microbial dynamics, meaning that computational methods for studying microbial systems need accurate ways to model the crowding conditions. We previously developed a computational framework, termed CROMICS, that incorporates the effect of the (time-dependent) crowding conditions on the spatio-temporal modeling of microbial communities, and we used it to demonstrate the crowding influence on the community dynamics. To further identify scenarios where crowding should be considered in microbial modeling, we herein applied and extended CROMICS to simulate several environmental conditions that could potentially boost or dampen the crowding influence in biofilms. We explore whether the nutrient supply (rich- or low-nutrient media), the cell-packing configuration (square or hexagonal spherical cell arrangement), or the cell growing conditions (planktonic state or biofilm) modify the crowding influence on the growth of Escherichia coli. Our results indicate that the growth rate, the abundance and appearance time of different cell phenotypes as well as the amount of by-products secreted to the medium are sensitive to some extent to the local crowding conditions in all scenarios tested, except in rich-nutrient media. Crowding conditions enhance the formation of nutrient gradient in biofilms, but its effect is only appreciated when cell metabolism is controlled by the nutrient limitation. Thus, as soon as biomass (and/or any other extracellular macromolecule) accumulates in a region, and cells occupy more than 14% of the volume fraction, the crowding effect must not be underestimated, as the microbial dynamics start to deviate from the ideal/expected behaviour that assumes volumeless cells or when a homogeneous (reduced) diffusion is applied in the simulation. The modeling and simulation of the interplay between the species diversity (cell shape and metabolism) and the environmental conditions (nutrient quality, crowding conditions) can help to design effective strategies for the optimization and control of microbial systems.}, } @article {pmid34292376, year = {2021}, author = {Pinto, LF and Andriolo, BNG and Hofling-Lima, AL and Freitas, D}, title = {The role of Acanthamoeba spp. in biofilm communities: a systematic review.}, journal = {Parasitology research}, volume = {120}, number = {8}, pages = {2717-2729}, pmid = {34292376}, issn = {1432-1955}, mesh = {*Acanthamoeba ; Bacteria ; *Biofilms ; Contact Lenses ; Hospitals ; Humans ; Observational Studies as Topic ; }, abstract = {Acanthamoeba spp. have always caused disease in immunosuppressed patients, but since 1986, they have become a worldwide public health issue by causing infection in healthy contact lens wearers. Amoebae of the Acanthamoeba genus are broadly distributed in nature, living either freely or as parasites, and are frequently associated with biofilms throughout the environment. These biofilms provide the parasite with protection against external aggression, thus favoring its increased pathogeny. This review aims to assess observational studies on the association between Acanthamoeba spp. and biofilms, opening potential lines of research on this severe ocular infection. A systematic literature search was conducted in May 2020 in the following databases: PubMed Central[®]/Medline, LILACS, The Cochrane Library, and EMBASE[®]. The studies were selected following the inclusion and exclusion criteria specifically defined for this review. Electronic research recovered 353 publications in the literature. However, none of the studies met the inclusion criterion of biofilm-producing Acanthamoeba spp., inferring that the parasite does not produce biofilms. Nonetheless, 78 studies were classified as potentially included regarding any association of Acanthamoeba spp. and biofilms. These studies were allocated across six different locations (hospital, aquatic, ophthalmic and dental environments, biofilms produced by bacteria, and other places). Acanthamoeba species use biofilms produced by other microorganisms for their benefit, in addition to them providing protection to and facilitating the dissemination of pathogens residing in them.}, } @article {pmid34291404, year = {2021}, author = {Kašparová, P and Zmuda, M and Vaňková, E and Maťátková, O and Masák, J}, title = {Low-molecular weight chitosan enhances antibacterial effect of antibiotics and permeabilizes cytoplasmic membrane of Staphylococcus epidermidis biofilm cells.}, journal = {Folia microbiologica}, volume = {66}, number = {6}, pages = {983-996}, pmid = {34291404}, issn = {1874-9356}, support = {CZ.2.16/3.1.00/24503//Operational Programme Prague - Competitiveness/ ; NPU I LO1601//National Programme of Sustainability I/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Cell Membrane ; *Chitosan/pharmacology ; Microbial Sensitivity Tests ; Molecular Weight ; Staphylococcus epidermidis ; }, abstract = {This study evaluated the effect of low-molecular weight chitosan on Staphylococcus epidermidis, a common colonizer of joint implants and other prosthetic devices. We have also attempted to elucidate its mechanism of action. Chitosan was found to be effective against both the planktonic and biofilm cells (MIC80 35-40 mg/L; MBIC80 40-150 mg/L), in contrast to the antibiotics erythromycin and tetracycline with no antibiofilm activity (MBIC80 not found). In combination, chitosan had an additive effect with antibiotics on suspension growth of S. epidermidis (FICi 0.7-1.0), and the combinatory action caused a complete inhibition of biofilm metabolic activity in some cases. In addition, chitosan caused rapid cellular damage and enhanced antihaemolytic activity of tetracycline in combination towards S. epidermidis biofilm cells. Chitosan efficiently inhibited S. epidermidis growth acting via cell membrane damage, yet the extent of antimicrobial and antibiofilm activities was quite strain-specific. It was proved to be a very efficient antimicrobial agent worth further examination as a potent candidate in pharmaceutical research. Apart from antimicrobial activity, it also acted as antivirulence enhancing agent which is a very promising strategy for alternative infectious diseases treatment.}, } @article {pmid34290996, year = {2021}, author = {Haghighifar, E and Norouzi, F and Kamali Dolatabadi, R}, title = {Molecular detection of Extended-Spectrum β-lactamases (ESBLs) and biofilm formation in uropathogen Klebsiella pneumoniae in Iran.}, journal = {Medical journal of the Islamic Republic of Iran}, volume = {35}, number = {}, pages = {72}, pmid = {34290996}, issn = {1016-1430}, abstract = {Background: Uropathogenic Klebsiella pneumoniae is one of the well-kown uropathogens that have the main rule in biofilm formation. Increased prevalence of ESBL enzyme is one of the therapeutic problems. However, the aims of this study were to characterize the ability of biofilm formation and ESBL-producing isolates produced by urinary tract infection's K. pneumoniae to identify the prevalence of this type of infection in the studied area. Methods: Between the 500 nonrepetitive clinical isolates, 128 isolates were detected as K. pneumoniae. Biofilm production of these isolates was showed by Merrit and Christensen method. The standard Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing. The phenotype ESBL was confirmed by double disc synergy test (DDST). Genotypic identification of ESBLs did by molecular detection. The statistical analysis was done using software IBM SPSS Statistics (SPSS Inc) and chi-square and Fisher exact tests. Results: The result of microtiter plate was observed and it was found that 86 (67.2%) isolates had weak biofilm, 24 (18.8%) moderate biofilm, and 18 (14.1%) strong biofilm. Also, 57 (44.5%) out of 128 isolates were diagnosed as MDR. The highest frequency of resistance was identified for cefotaxime 60 (46.9%) and tetracycline 60 (46.9%), and the lowest rate was for amikacin 16 (12.5%). The results of DDST showed 55 of 128 (43%) produced ESBL enzymes. PCR detection in ESBL-producing isolates showed contained blaTEM 33 of 55(63.1%), and blaVEB 13 of 55 (23%). Also, 1 of 55 (2%) had both blaTEM and blaVEB . Also, 5 of 13 (38.4%) isolates that had the blaVEB gene were also MDR and had weak biofilm (8/13; 61.5%), intermediate biofilm (3/13; 23%), and strong biofilm (2/13; 15.4%). Conclusion: To decrease treatment complications and mortality rate of drug-resistant bacterial infections, rapid detection of β-lactamases genes and evaluation of these properties and infection management programs can help to prevent the transmission of drug resistant-strains.}, } @article {pmid34289670, year = {2021}, author = {Carli, E and Pasini, M and Lardani, L and Giuca, G and Miceli, M}, title = {Impact of self-ligating orthodontic brackets on dental biofilm and periodontal pathogens in adolescents.}, journal = {Journal of biological regulators and homeostatic agents}, volume = {35}, number = {3 Suppl. 1}, pages = {107-115}, doi = {10.23812/21-3supp1-13}, pmid = {34289670}, issn = {0393-974X}, mesh = {Adolescent ; Biofilms ; Child ; Dental Plaque Index ; Female ; *Gingivitis ; Humans ; Male ; *Orthodontic Brackets ; Periodontal Index ; Prospective Studies ; }, abstract = {The aim of the present prospective study was to evaluate periodontal health and subgingival microbiological alterations in adolescents treated with fixed self ligating orthodontic brackets in comparison to subject without any orthodontic appliance. A total of 40 adolescents (23 females and 17 males; mean age: 13.2 ± 3.2 years) were included: 30 subjects with self ligating brackets (test group) and 10 patients without orthodontic appliances (control group). Follow-ups were as follows: T1 (1 month), T2 (3 months), T3 (6 months) from the beginning of the orthodontic therapy. Clinical parameters (plaque index, gingival index and clinical attachment level) were measured for every patient and a microbiological analysis was performed. Mann Whitney test was performed to evaluate clinical parameters between test and control group and Friedman test and Fisher test were adopted to evaluate intra group differences at different follow-ups. Student T-test was performed to compare clinical attachment level between the two groups. Significance level was set at p<0.05. No periodontal pathogens and no clinical attachment loss were found in the whole sample. A slightly higher plaque index and gingival inflammation were recorded in the test group in comparison to the controls.}, } @article {pmid34288701, year = {2021}, author = {Majzoub, ME and McElroy, K and Maczka, M and Schulz, S and Thomas, T and Egan, S}, title = {Genomic Evolution of the Marine Bacterium Phaeobacter inhibens during Biofilm Growth.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {19}, pages = {e0076921}, pmid = {34288701}, issn = {1098-5336}, mesh = {Biofilms/*growth & development ; Evolution, Molecular ; Genetic Variation ; Mutation ; Phenotype ; *Rhodobacteraceae/genetics/growth & development/metabolism/physiology ; Tropolone/analogs & derivatives/metabolism ; }, abstract = {Phaeobacter inhibens 2.10 is an effective biofilm former on marine surfaces and has the ability to outcompete other microorganisms, possibly due to the production of the plasmid-encoded secondary metabolite tropodithietic acid (TDA). P. inhibens 2.10 biofilms produce phenotypic variants with reduced competitiveness compared to the wild type. In the present study, we used longitudinal, genome-wide deep sequencing to uncover the genetic foundation that contributes to the emergent phenotypic diversity in P. inhibens 2.10 biofilm dispersants. Our results show that phenotypic variation is not due to the loss of the plasmid that carries the genes for TDA synthesis but instead show that P. inhibens 2.10 biofilm populations become rapidly enriched in single nucleotide variations in genes involved in the synthesis of TDA. While variants in genes previously linked to other phenotypes, such as lipopolysaccharide production (i.e., rfbA) and cellular persistence (i.e., metG), also appear to be selected for during biofilm dispersal, the number and consistency of variations found for genes involved in TDA production suggest that this metabolite imposes a burden on P. inhibens 2.10 cells. Our results indicate a strong selection pressure for the loss of TDA in monospecies biofilm populations and provide insight into how competition (or a lack thereof) in biofilms might shape genome evolution in bacteria. IMPORTANCE Biofilm formation and dispersal are important survival strategies for environmental bacteria. During biofilm dispersal, cells often display stable and heritable variants from the parental biofilm. Phaeobacter inhibens is an effective colonizer of marine surfaces, in which a subpopulation of its biofilm dispersal cells displays a noncompetitive phenotype. This study aimed to elucidate the genetic basis of these phenotypic changes. Despite the progress made to date in characterizing the dispersal variants in P. inhibens, little is understood about the underlying genetic changes that result in the development of the specific variants. Here, P. inhibens phenotypic variation was linked to single nucleotide polymorphisms (SNPs), in particular in genes affecting the competitive ability of P. inhibens, including genes related to the production of the antibiotic tropodithietic acid (TDA) and bacterial cell-cell communication (e.g., quorum sensing). This work is significant as it reveals how the biofilm lifestyle might shape genome evolution in a cosmopolitan bacterium.}, } @article {pmid34287490, year = {2021}, author = {Evangelista, SS and Santos, SGD and Oliveira, AC}, title = {Impact of the contamination time by Escherichia coli on biofilm formation in surgical instruments.}, journal = {Revista brasileira de enfermagem}, volume = {74}, number = {3}, pages = {e20200759}, doi = {10.1590/0034-7167-2020-0759}, pmid = {34287490}, issn = {1984-0446}, mesh = {Biofilms ; Colony Count, Microbial ; *Escherichia coli ; Humans ; *Stainless Steel ; Surgical Instruments ; }, abstract = {OBJECTIVES: to evaluate the microbial load and adherence of Escherichia coli in different areas of the surgical instrument surface exposed to experimental contamination over time.

METHODS: experimental study in which fragments of crile forceps (serrated, rod and rack) were contaminated by immersion in Tryptic Soy Broth, containing 106 CFU/mL of E. coli, for 1, 2, 4, 6, 8, 12 and 24 hours. Microbial load and bacterial adherence were evaluated using microbiological culture and scanning electron microscopy, respectively.

RESULTS: there was an increase in the microbial load on the surgical instrument, proportional to the contamination interval, ranging from 102 after 1 hour to 105 CFU/cm2 in 24 hours. The presence of exopolysaccharide was detected after two hours of contamination.

CONCLUSIONS: microbial load and adhesion of E. coli increased over time, reaching 105 CFU/cm2 after 24 hours of contamination, starting biofilm formation after two hours.}, } @article {pmid34287032, year = {2021}, author = {Fan, SH and Matsuo, M and Huang, L and Tribelli, PM and Götz, F}, title = {The MpsAB Bicarbonate Transporter Is Superior to Carbonic Anhydrase in Biofilm-Forming Bacteria with Limited CO2 Diffusion.}, journal = {Microbiology spectrum}, volume = {9}, number = {1}, pages = {e0030521}, pmid = {34287032}, issn = {2165-0497}, mesh = {Amino Acid Sequence ; Bacteria/enzymology/genetics/*metabolism ; Bacterial Proteins/chemistry/genetics/*metabolism ; Bicarbonates/*metabolism ; Biofilms ; Carbon Dioxide/*metabolism ; Carbonic Anhydrases/chemistry/genetics/*metabolism ; Gene Deletion ; Membrane Transport Proteins/chemistry/genetics/*metabolism ; Sequence Alignment ; }, abstract = {CO2 and bicarbonate are required for carboxylation reactions, which are essential in most bacteria. To provide the cells with sufficient CO2, there exist two dissolved inorganic carbon supply (DICS) systems: the membrane potential-generating system (MpsAB) and the carbonic anhydrase (CA). Recently, it has been shown that MpsAB is a bicarbonate transporter that is present not only in photo- and autotrophic bacteria, but also in a diverse range of nonautotrophic microorganisms. Since the two systems rarely coexist in a species but are interchangeable, we investigated what advantages the one system might have over the other. Using the genus Staphylococcus as a model, we deleted the CA gene can in Staphylococcus carnosus and mpsABC genes in Staphylococcus aureus. Deletion of the respective gene in one or the other species led to growth inhibition that could only be reversed by CO2 supplementation. While the S. carnosus Δcan mutant could be fully complemented with mpsABC, the S. aureus ΔmpsABC mutant was only partially complemented by can, suggesting that MpsAB outperforms CA. Interestingly, we provide evidence that mucus biofilm formation such as that involving polysaccharide intercellular adhesin (PIA) impedes the diffusion of CO2 into cells, making MpsAB more advantageous in biofilm-producing strains or species. Coexpression of MpsAB and CA does not confer any growth benefits, even under stress conditions. In conclusion, the distribution of MpsAB or CA in bacteria does not appear to be random as expression of bicarbonate transporters provides an advantage where diffusion of CO2 is impeded. IMPORTANCE CO2 and bicarbonate are required for carboxylation reactions in central metabolism and biosynthesis of small molecules in all bacteria. This is achieved by two different systems for dissolved inorganic carbon supply (DICS): these are the membrane potential-generating system (MpsAB) and the carbonic anhydrase (CA), but both rarely coexist in a given species. Here, we compared both systems and demonstrate that the distribution of MpsAB and/or CA within the phylum Firmicutes is apparently not random. The bicarbonate transporter MpsAB has an advantage in species where CO2 diffusion is hampered-for instance, in mucus- and biofilm-forming bacteria. However, coexpression of MpsAB and CA does not confer any growth benefits, even under stress conditions. Given the clinical relevance of Staphylococcus in the medical environment, such findings contribute to the understanding of bacterial metabolism and thus are crucial for exploration of potential targets for antimicrobials. The knowledge gained here as exemplified by staphylococcal species could be extended to other pathogenic bacteria.}, } @article {pmid34285314, year = {2021}, author = {Cavalheiro, M and Pereira, D and Formosa-Dague, C and Leitão, C and Pais, P and Ndlovu, E and Viana, R and Pimenta, AI and Santos, R and Takahashi-Nakaguchi, A and Okamoto, M and Ola, M and Chibana, H and Fialho, AM and Butler, G and Dague, E and Teixeira, MC}, title = {From the first touch to biofilm establishment by the human pathogen Candida glabrata: a genome-wide to nanoscale view.}, journal = {Communications biology}, volume = {4}, number = {1}, pages = {886}, pmid = {34285314}, issn = {2399-3642}, mesh = {Biofilms/*growth & development ; Candida glabrata/genetics/*physiology ; *Genome, Fungal ; Transcription Factors/*genetics/metabolism ; }, abstract = {Candida glabrata is an opportunistic pathogen that adheres to human epithelial mucosa and forms biofilm to cause persistent infections. In this work, Single-cell Force Spectroscopy (SCFS) was used to glimpse at the adhesive properties of C. glabrata as it interacts with clinically relevant surfaces, the first step towards biofilm formation. Following a genetic screening, RNA-sequencing revealed that half of the entire transcriptome of C. glabrata is remodeled upon biofilm formation, around 40% of which under the control of the transcription factors CgEfg1 and CgTec1. Using SCFS, it was possible to observe that CgEfg1, but not CgTec1, is necessary for the initial interaction of C. glabrata cells with both abiotic surfaces and epithelial cells, while both transcription factors orchestrate biofilm maturation. Overall, this study characterizes the network of transcription factors controlling massive transcriptional remodelling occurring from the initial cell-surface interaction to mature biofilm formation.}, } @article {pmid34283223, year = {2021}, author = {Díez-Aguilar, M and Ekkelenkamp, M and Morosini, MI and Huertas, N and Del Campo, R and Zamora, J and Fluit, AC and Tunney, MM and Obrecht, D and Bernardini, F and Cantón, R}, title = {Anti-biofilm activity of murepavadin against cystic fibrosis Pseudomonas aeruginosa isolates.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {76}, number = {10}, pages = {2578-2585}, doi = {10.1093/jac/dkab222}, pmid = {34283223}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cystic Fibrosis ; Humans ; Microbial Sensitivity Tests ; Peptides, Cyclic ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; }, abstract = {OBJECTIVES: To determine the activity of murepavadin in comparison with tobramycin, colistin and aztreonam, against cystic fibrosis (CF) Pseudomonas aeruginosa isolates growing in biofilms. The biofilm-epidemiological cut-off (ECOFF) values that include intrinsic resistance mechanisms present in biofilms were estimated.

METHODS: Fifty-three CF P. aeruginosa isolates from respiratory samples were tested using the Calgary (closed system) device, while 4 [2 clinical (one smooth, one mucoid) and 2 reference strains] were tested using the BioFlux, a microfluidic open model of biofilm testing. Biofilm was stained with SYTO9® and propidium iodide. The minimal biofilm inhibitory concentration (MBIC) and the minimal biofilm eradication concentration (MBEC) were determined. The MBIC-ECOFF and the MBEC-ECOFF were calculated.

RESULTS: Colistin, tobramycin and murepavadin presented similar MBIC50/MBIC90 values (4/32, 8/64 and 2/32, respectively). Murepavadin exhibited the lowest MBEC90 (64 mg/L). Aztreonam MBIC and MBEC values were higher than those of the other antibiotics tested. Tobramycin and murepavadin had the lowest MBEC-ECOFF (64 and 128 mg/L, respectively), while those of aztreonam and colistin exceeded 512 mg/L. Using the BioFlux, for the PAO1, PAO mutS and the smooth clinical strain, a significant difference (P < 0.0125) was observed when comparing the fluorescence of treated and untreated biofilms. For the mucoid strain, only the biofilm treated with aztreonam (MBIC and MBEC) and tobramycin (MBEC) showed differences with respect to the untreated biofilm.

CONCLUSIONS: Murepavadin demonstrated good activity against P. aeruginosa biofilms both in open and closed systems. The MBIC-ECOFF and the MBEC-ECOFF are proposed as new parameters to estimate the activity of antibiotics on biofilms.}, } @article {pmid34280601, year = {2021}, author = {Li, X and Chen, D and Xie, S}, title = {Current progress and prospects of organic nanoparticles against bacterial biofilm.}, journal = {Advances in colloid and interface science}, volume = {294}, number = {}, pages = {102475}, doi = {10.1016/j.cis.2021.102475}, pmid = {34280601}, issn = {1873-3727}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; *Bacterial Infections ; Biofilms ; Humans ; *Nanoparticles ; }, abstract = {Biofilm plays a vital role in the pathogenicity and resistance of bacteria, and is an important problem to be settled urgently in the treatment of bacterial diseases. Exploring effective strategies to control bacterial biofilm has become a hot research topic. Compared to other measures, organic nanomaterials have shown greater prospects in overcoming the problems of bacterial biofilms due to their unique properties. In order to explore more effective organic nanomaterials against biofilms, we used relevant keywords to search for related published publications on the Web of Science . On the basis of these searched publications, this review firstly summarized the properties, formulation, harmness, and treatment challenges of biofilm. Secondly, the current progress of organic nanomaterials against bacterial biofilm and its possible anti-biofilm mechanisms (e.g., reducing the adhesion of biofilms, enhancing the permeability of antimicrobial agents, maintaining drug stability, fighting against biofilm using specific actions) was analyzed. Thirdly, the influences on the anti-biofilm efficacy of organic nanomaterials were discussed from nanoparticles and biofilm characteristics. Finally, the challenges and prospects of organic nanoparticles against biofilm were concluded. This review may help researchers to realize the progress and challenges of nanoparticles against biofilm and thus help to design more efficient organic nanomaterial to fight against biofilms.}, } @article {pmid34280443, year = {2021}, author = {Perwez, M and Mazumder, JA and Noori, R and Sardar, M}, title = {Magnetic combi CLEA for inhibition of bacterial biofilm: A green approach.}, journal = {International journal of biological macromolecules}, volume = {186}, number = {}, pages = {780-787}, doi = {10.1016/j.ijbiomac.2021.07.091}, pmid = {34280443}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Enzyme Stability ; Enzymes, Immobilized/chemistry/metabolism/*pharmacology ; Escherichia coli/*drug effects/growth & development/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; *Green Chemistry Technology ; Hydrolysis ; *Magnetics ; Multienzyme Complexes/chemistry/metabolism/*pharmacology ; Staphylococcus aureus/*drug effects/growth & development/metabolism ; }, abstract = {In the present study different enzymes (α- amylase, trypsin, cellulase, horse-radish peroxidase and pectinex ultra clear) were studied for bacterial biofilm inhibition and Pectinex ultra clear showed best inhibition. So, m-combi-CLEA of Pectinex ultra clear was developed by cross linked enzyme aggregate (CLEA) formation on APTES (3-aminopropyltriethoxysilane) modified iron oxide nanoparticles. Different parameters were optimized and it was observed that 0.4 mg/ml of protein (containing 25 U/mg cellulase activity), 0.5 mg/ml BSA and 10 mM glutaraldehyde when incubated for 3 h gives 100% enzyme activity using ethanol as the precipitant. The CLEA formed were thermally more stable as compared to free enzyme. m-combi-CLEA of Pectinex ultra clear shows 75-78% biofilm inhibition of E. coli and S. aureus. Furthermore, m-combi-CLEA can be reused till 4 cycles with same efficiency. The carbohydrate contents of E. coli biofilm decreased from 64.629 μg to 6.23 μg and for S. aureus biofilm, it decreased from 58.46 μg to 5.52 μg when treated with m-combi CLEA in comparison to untreated biofilms. FTIR, darkfield illumination Fluorescence Microscopy, and Scanning Electron Microscopy was further used for characterization.}, } @article {pmid34280035, year = {2021}, author = {White, AN and Learman, BS and Brauer, AL and Armbruster, CE}, title = {Catalase Activity is Critical for Proteus mirabilis Biofilm Development, Extracellular Polymeric Substance Composition, and Dissemination during Catheter-Associated Urinary Tract Infection.}, journal = {Infection and immunity}, volume = {89}, number = {10}, pages = {e0017721}, pmid = {34280035}, issn = {1098-5522}, support = {R00 DK105205/DK/NIDDK NIH HHS/United States ; R01 DK123158/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteremia/drug therapy/microbiology ; Biofilms/drug effects/*growth & development ; Catalase/*metabolism ; Catheter-Related Infections/drug therapy/*microbiology ; Catheters/microbiology ; Coinfection/drug therapy/microbiology ; Extracellular Polymeric Substance Matrix/*metabolism ; Female ; Humans ; Mice ; Mice, Inbred CBA ; Proteus Infections/drug therapy/*microbiology ; Proteus mirabilis/drug effects/*enzymology ; Urinary Tract Infections/drug therapy/*microbiology ; }, abstract = {Proteus mirabilis is a leading uropathogen of catheter-associated urinary tract infections (CAUTIs), which are among the most common health care-associated infections worldwide. A key factor that contributes to P. mirabilis pathogenesis and persistence during CAUTI is the formation of catheter biofilms, which provide increased resistance to antibiotic treatment and host defense mechanisms. Another factor that is important for bacterial persistence during CAUTI is the ability to resist reactive oxygen species (ROS), such as through the action of the catalase enzyme. Potent catalase activity is one of the defining biochemical characteristics of P. mirabilis, and the single catalase (katA) gene in strain HI4320 was recently identified as a candidate fitness factor for UTI, CAUTI, and bacteremia. Here, we show that disruption of katA results in increased ROS levels, increased sensitivity to peroxide, and decreased biofilm biomass. The biomass defect was due to a decrease in the production of extracellular polymeric substances (EPS) by the ΔkatA mutant and specifically due to reduced carbohydrate content. Importantly, the biofilm defect resulted in decreased antibiotic resistance in vitro and a colonization defect during experimental CAUTI. The ΔkatA mutant also exhibited decreased fitness in a bacteremia model, supporting a dual role for catalase in P. mirabilis biofilm development and immune evasion.}, } @article {pmid34278512, year = {2021}, author = {van Geelen, L and Kaschani, F and Sazzadeh, SS and Adeniyi, ET and Meier, D and Proksch, P and Pfeffer, K and Kaiser, M and Ioerger, TR and Kalscheuer, R}, title = {Correction to: Natural brominated phenoxyphenols kill persistent and biofilm-incorporated cells of MRSA and other pathogenic bacteria.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {14-15}, pages = {6119}, doi = {10.1007/s00253-021-11409-5}, pmid = {34278512}, issn = {1432-0614}, } @article {pmid34278381, year = {2021}, author = {Thuile Bistarelli, L and Poyntner, C and Santín, C and Doerr, SH and Talluto, MV and Singer, G and Sigmund, G}, title = {Wildfire-Derived Pyrogenic Carbon Modulates Riverine Organic Matter and Biofilm Enzyme Activities in an In Situ Flume Experiment.}, journal = {ACS ES&T water}, volume = {1}, number = {7}, pages = {1648-1656}, pmid = {34278381}, issn = {2690-0637}, abstract = {Wildfires produce large amounts of pyrogenic carbon (PyC), including charcoal, known for its chemical recalcitrance and sorption affinity for organic molecules. Wildfire-derived PyC can be transported to fluvial networks. Here it may alter the dissolved organic matter (DOM) concentration and composition as well as microbial biofilm functioning. Effects of PyC on carbon cycling in freshwater ecosystems remain poorly investigated. Employing in-stream flumes with a control versus treatment design (PyC pulse addition), we present evidence that field-aged PyC inputs to rivers can increase the dissolved organic carbon (DOC) concentration and alter the DOM composition. DOM fluorescence components were not affected by PyC. The in-stream DOM composition was altered due to leaching of pyrogenic DOM from PyC and possibly concurrent sorption of riverine DOM to PyC. Decreased DOM aromaticity indicated by a lower SUVA245 (-0.31 unit) and a higher pH (0.25 unit) was associated with changes in enzymatic activities in benthic biofilms, including a lower recalcitrance index (β-glucosidase/phenol oxidase), suggesting preferential usage of recalcitrant over readily available DOM by biofilms. The deposition of particulate PyC onto biofilms may further modulate the impacts of PyC due to direct contact with the biofilm matrix. This study highlights the importance of PyC for in-stream biogeochemical organic matter cycling in fire-affected watersheds.}, } @article {pmid34277863, year = {2021}, author = {Mirzaei, B and Babaei, R and Haghshenas, MR and Mohammadi, F and Homayoni, P and Shafaei, E}, title = {PIA and rSesC Mixture Arisen Antibodies Could Inhibit the Biofilm-Formation in Staphylococcus aureus.}, journal = {Reports of biochemistry & molecular biology}, volume = {10}, number = {1}, pages = {1-12}, pmid = {34277863}, issn = {2322-3480}, abstract = {BACKGROUND: Staphylococcus aureus as a causative agent of hospital-acquired infections has been considered as the primary concern in biomaterial-related infections (BAIs).

METHODS: Following the purification of polysaccharide intercellular adhesion (PIA) as an efficient macromolecule in biofilm formation in the native condition, recombinant S. epidermidis surface-exposed rSesC protein, with the most homology to clumping factor A (ClfA) in S. aureus was cloned and expressed in a prokaryotic host as well. Fourier transform infrared spectrometry (FTIR) and Western blotting procedure analyzed purified PIA and protein, respectively. Then, the immune response was evaluated by measuring total IgG titers. Moreover, the capacity of Anti-biofilm forming activity of arisen antibodies to a biofilm-forming S. aureus strains was assessed by the semi-quantitative micro-plate procedure.

RESULTS: Data showed that the total IgGs were boosted in mice immunized sera. By performing an inhibition assay, the biofilm inhibitory effect of secreted antibodies to test strain was observed. Arisen antibodies against the mixture significantly were more potent than PIA and rSesC, when comparing individual antigens in a biofilm inhibition assay.

CONCLUSION: immunization of mice with mentioned antigens especially a mixture of them, could eliminate the biofilm formation process in S. aureus. Hopefully, this study corresponds to the suggestion that the immunization of mice with PIA and rSesC candidate vaccines could protect against S. aureus infection.}, } @article {pmid34276635, year = {2021}, author = {Talukdar, PK and Turner, KL and Crockett, TM and Lu, X and Morris, CF and Konkel, ME}, title = {Inhibitory Effect of Puroindoline Peptides on Campylobacter jejuni Growth and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {702762}, pmid = {34276635}, issn = {1664-302X}, abstract = {Puroindolines are small, amphipathic, wheat proteins that determine the hardness of the wheat kernel and protect crops from different pathogens. Puroindoline A (PinA) and puroindoline B (PinB) are two major isoforms of puroindolines. These proteins have antibacterial and antifungal properties mainly attributed to their characteristic tryptophan-rich domains (TRDs). In this in vitro study, we investigated the antimicrobial effect of PinA and PinB synthetic peptides against the growth and biofilm formation of Campylobacter jejuni. C. jejuni is an important microaerobic, foodborne pathogen that causes gastrointestinal and neurological diseases in humans. Our results showed that: (1) PinA, but not PinB, has strong antimicrobial activity against C. jejuni clinical strains 81-176 and F38011, Escherichia coli O157:H7, methicillin-resistant Staphylococcus aureus, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes; (2) The substitution of two tryptophan residues to glycine (W→G) in the TRD of PinA abolishes its antimicrobial activity against these microorganisms; (3) PinA functions additively with two common antibiotics (ciprofloxacin and erythromycin) to inhibit or inactivate C. jejuni strains; (4) PinA damages the C. jejuni cellular membrane, (5) PinA is cytotoxic to human INT 407 cells at high concentrations; and (6) PinA inhibits C. jejuni biofilm formation. In summary, this study demonstrates the antimicrobial activity of PinA against C. jejuni growth and biofilm formation and further confirms the potential use of PinA as a therapeutic agent in health care or as preservatives in the agri-food industry.}, } @article {pmid34276580, year = {2021}, author = {Gorokhova, E and Motiei, A and El-Shehawy, R}, title = {Understanding Biofilm Formation in Ecotoxicological Assays With Natural and Anthropogenic Particulates.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {632947}, pmid = {34276580}, issn = {1664-302X}, abstract = {Fossil-made polymers harbor unique bacterial assemblages, and concerns have been raised that ingested microplastic may affect the consumer gut microbiota and spread pathogens in animal populations. We hypothesized that in an ecotoxicity assay with a mixture of polystyrene (PS) and clay: (1) microbiome of the test animals inoculates the system with bacteria; (2) relative contribution of PS and the total amount of suspended solids (SS) select for specific bacterial communities; and (3) particle aggregation is affected by biofilm community composition, with concomitant effects on the animal survival. Mixtures of PS and clay at different concentrations of SS (10, 100, and 1000 mg/L) with a varying microplastics contribution (%PS; 0-80%) were incubated with Daphnia magna, whose microbiome served as an inoculum for the biofilms during the exposure. After 4-days of exposure, we examined the biofilm communities by 16S rRNA gene sequencing, particle size distribution, and animal survival. The biofilm communities were significantly different from the Daphnia microbiota used to inoculate the system, with an overrepresentation of predatory, rare, and potentially pathogenic taxa in the biofilms. The biofilm diversity was stimulated by %PS and decreased by predatory bacteria. Particle aggregate size and the biofilm composition were the primary drivers of animal survival, with small particles and predatory bacteria associated with a higher death rate. Thus, in effect studies with solid waste materials, ecological interactions in the biofilm can affect particle aggregation and support potentially harmful microorganisms with concomitant effects on the test animals.}, } @article {pmid34274586, year = {2021}, author = {Ren, L and Chen, M and Zheng, J and Li, Z and Tian, C and Wang, Q and Wang, Z}, title = {Efficacy of a novel electrochemical membrane-aerated biofilm reactor for removal of antibiotics from micro-polluted surface water and suppression of antibiotic resistance genes.}, journal = {Bioresource technology}, volume = {338}, number = {}, pages = {125527}, doi = {10.1016/j.biortech.2021.125527}, pmid = {34274586}, issn = {1873-2976}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Bioreactors ; Drug Resistance, Microbial/genetics ; Sulfamethoxazole ; *Wastewater ; Water ; }, abstract = {An electrochemical membrane-aerated biofilm reactor (EMABR) was developed for removing sulfamethoxazole (SMX) and trimethoprim (TMP) from contaminated water. The exertion of electric field greatly enhanced the degradation of SMX and TMP in the EMABR (~60%) compared to membrane-aerated biofilm reactor (MABR, < 10%), due to the synergistic effects of the electro-oxidation (the generation of reactive oxygen species) and biological degradation. Microbial community analyses demonstrated that the EMABR enriched the genus of Xanthobacter, which was potentially capable of degrading aromatic intermediates. Moreover, the EMABR had a lower relative abundance of antibiotic resistance genes (ARGs) (0.23) compared to the MABR (0.56), suggesting the suppression of ARGs in the EMABR. Further, the SMX and TMP degradation pathways were proposed based on the detection of key intermediate products. This study demonstrated the potential of EMABR as an effective technology for removing antibiotics from micro-polluted surface water and suppressing the development of ARGs.}, } @article {pmid34273854, year = {2021}, author = {Desai, D and Goh, KGK and Sullivan, MJ and Chattopadhyay, D and Ulett, GC}, title = {Hemolytic activity and biofilm-formation among clinical isolates of group B streptococcus causing acute urinary tract infection and asymptomatic bacteriuria.}, journal = {International journal of medical microbiology : IJMM}, volume = {311}, number = {6}, pages = {151520}, doi = {10.1016/j.ijmm.2021.151520}, pmid = {34273854}, issn = {1618-0607}, mesh = {*Bacteriuria ; Biofilms ; Hemolysis ; Humans ; Streptococcus agalactiae ; *Urinary Tract Infections ; }, abstract = {Streptococcus agalactiae, also known as group B Streptococcus, is an aetiological agent of urinary tract infection (UTI) in adults, including cystitis, pyelonephritis and asymptomatic bacteriuria (ABU). Whereas ABU-causing S. agalactiae (ABSA) have been shown to grow and achieve higher culture denstity in human urine compared to uropathogenic S. agalactiae (UPSA) other phenotypic distinctions between S. agalactiae isolated from different forms of UTI are not known. Here, we define the hemolytic activities and biofilm-formation of a collection of clinical isolates of UPSA, ABSA and recurrent S. agalactiae bacteriuria (rSAB) strains to explore these phenotypes in the context of clinical history of isolates. A total of 61 UPSA, 184 ABSA, and 47 rSAB isolates were analyzed for relative hemolytic activity by spot assay on blood agar, which was validated using a erythrocyte lysis suspension assay. Biofilm formation was determined by microtiter plate assay with Lysogeny and Todd-Hewitt broths supplemented with 1% glucose to induce biofilm formation. We also used multiplex PCR to analyze isolates for the presence of genes encoding adhesive pili, which contribute to biofilm formation. Comparing the hemolytic activities of 292 isolates showed, surprisingly, that ABSA strains were significantly more likely to be highly hemolytic compared to other strains. In contrast, there were no differences between the relative abilities of strains from the different clinical history groups to form biofilms. Taken together, these findings demonstrate a propensity of S. agalactiae causing ABU to be highly hemolytic but no link between clinical history of UTI strains and ability to form biofilm.}, } @article {pmid34273699, year = {2021}, author = {Taşkan, B and Taşkan, E}, title = {Inhibition of AHL-mediated quorum sensing to control biofilm thickness in microbial fuel cell by using Rhodococcus sp. BH4.}, journal = {Chemosphere}, volume = {285}, number = {}, pages = {131538}, doi = {10.1016/j.chemosphere.2021.131538}, pmid = {34273699}, issn = {1879-1298}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Extracellular Polymeric Substance Matrix ; Quorum Sensing ; *Rhodococcus ; }, abstract = {Anode biofilm thickness is a key point for high and sustainable power generation in microbial fuel cells (MFCs). Over time, the formation of a thicker biofilm on anode electrode hinders the power generation performance of MFC by causing a longer electron transfer path and the accumulation of undesirable components in anode biofilm. To overcome these limitations, we used a novel strategy named quorum quenching (QQ) for the first time in order to control the biofilm thickness on the anode surface by inactivation of signal molecules among microorganisms. For this purpose, the isolated QQ bacteria (Rhodococcus sp. BH4) were immobilized into alginate beads (20, 40, and 80 mg/10 ml sodium alginate) and added to the anode chamber of MFCs. The MFC exhibited the best electrochemical activity (1924 mW m[-2]) with a biofilm thickness of 26 μm at 40 mg Rhodococcus sp. BH4/10 ml sodium alginate. The inhibition of signal molecules in anode chamber reduced the production of extracellular polymeric substance (EPS) by preventing microbial communication amonganode microorganisms. Microscopic observations revealed that anode biofilm thickness and the abundance of dead bacteria significantly decreased with an increase in Rhodococcus sp. BH4 concentration in MFCs. Microbiome diversity showed an apparent difference among the microbial community structures of anode biofilms in MFCs containing vacant and Rhodococcus sp. BH4 beads. The data revealed that the QQ strategy is an efficient application for improving MFC performance and may shed light on future studies.}, } @article {pmid34272991, year = {2021}, author = {Paul, P and Das, S and Chatterjee, S and Shukla, A and Chakraborty, P and Sarkar, S and Maiti, D and Das, A and Tribedi, P}, title = {1,4-Naphthoquinone disintegrates the pre-existing biofilm of Staphylococcus aureus by accumulating reactive oxygen species.}, journal = {Archives of microbiology}, volume = {203}, number = {8}, pages = {4981-4992}, pmid = {34272991}, issn = {1432-072X}, mesh = {Biofilms ; Humans ; Naphthoquinones ; Reactive Oxygen Species ; *Staphylococcal Infections ; *Staphylococcus aureus/genetics ; }, abstract = {Staphylococcus aureus causes several nosocomial and community-acquired infections in human host involving biofilm. Thus, strategies need to be explored to curb biofilm threats by either inhibiting the formation of biofilm or disintegrating the pre-existing biofilm. Towards this direction, we had already revealed the biofilm inhibiting properties of 1,4-naphthoquinone against S. aureus. In this study, we have investigated whether this compound can act on pre-existing biofilm. Hence, biofilm of S. aureus was developed first and challenged further with 1,4-naphthoquinone. Experiments such as crystal violet assay, fluorescence microscopy, and estimation of total biofilm protein were performed to confirm the biofilm disintegration properties of 1,4-naphthoquinone. The disintegration of pre-existing biofilm could be attributed to the generation of reactive oxygen species (ROS). To investigate further, we observed that extracellular DNA (eDNA) was found to play an important role in holding the biofilm network as DNaseI treatment could cause an efficient disintegration of the same. To examine the effect of ROS on the eDNA, we exposed pre-existing biofilm to either 1,4-naphthoquinone or a combination of both 1,4-naphthoquinone and ascorbic acid for different length of time. Post-incubation, ROS generation and the amount of eDNA associated with the biofilm were determined wherein an inversely proportional relationship was observed between them. The result indicated that with the increase of ROS generation, the amount of eDNA associated with biofilm got decreased substantially. Thus, the results indicated that the generation of ROS could degrade the eDNA thereby compromising the integrity of biofilm which lead to the disintegration of pre-existing biofilm.}, } @article {pmid34270375, year = {2022}, author = {Álvarez, S and Leiva-Sabadini, C and Schuh, CMAP and Aguayo, S}, title = {Bacterial adhesion to collagens: implications for biofilm formation and disease progression in the oral cavity.}, journal = {Critical reviews in microbiology}, volume = {48}, number = {1}, pages = {83-95}, doi = {10.1080/1040841X.2021.1944054}, pmid = {34270375}, issn = {1549-7828}, mesh = {*Bacterial Adhesion ; *Biofilms ; Collagen ; Disease Progression ; Humans ; Mouth ; Porphyromonas gingivalis ; }, abstract = {Collagen is the most abundant structural protein in the body and the main component of the extracellular matrix of most tissues, including dentine and periodontal tissues. Despite the well-characterized role of collagen and specifically type-I collagen, as a ligand for host cells, its role as a substrate for bacterial adhesion and biofilm formation is less explored. Therefore, the purpose of this review is to discuss recent findings regarding the adhesion of oral bacteria to collagen surfaces and its role in the progression and severity of oral and systemic diseases. Initial oral colonizers such as streptococci have evolved collagen-binding proteins (cbp) that are important for the colonization of dentine and periodontal tissues. Also, periodontal pathogens such as Porphyromonas gingivalis and Tannerella forsythia utilise cbps for tissue sensing and subsequent invasion. The implications of bacteria-collagen coupling in the context of collagen biomaterials and regenerative dentistry approaches are also addressed. Furthermore, the importance of interdisciplinary techniques such as atomic force microscopy for the nanocharacterization of bacteria-collagen interactions is also considered. Overall, understanding the process of oral bacterial adhesion onto collagen is important for developing future therapeutic approaches against oral and systemic diseases, by modulating the early stages of biofilm formation.}, } @article {pmid34268142, year = {2021}, author = {Chaves, M and Vazquez-Valverde, D and Fernández-Jaramillo, H and Arias-Echandi, ML}, title = {The ability of Aliarcobacter butzleri strains isolated from foods of animal origin in Costa Rica to form biofilm.}, journal = {Italian journal of food safety}, volume = {10}, number = {2}, pages = {9020}, pmid = {34268142}, issn = {2239-7132}, abstract = {Aliarcobacter butzleri is a zoonotic emerging food and waterborne pathogen widely distributed in nature. It is present in food processing environments and can easily be spread through the food industry because of its ability to form biofilm. The aim of this work was to determine the ability of strains isolated in Costa Rica from different food matrixes of animal origin to form biofilm. Thirty-eight A. butzleri strains previously isolated and identified from animal origin products were analyzed using the method described by Stepmovic et al. (2000), in three culture broths, brain heart infusion broth, Boer broth and Houf broth. Results showed that 67% of poultry origin strains, 62.5% of meat origin strains and just 8% of milk origin strains showed ability to form biofilm. The findings of this study confirm the adherence ability of A. butzleri to form biofilm, a characteristic that can promote dispersion and cross contamination along food industry processing lines.}, } @article {pmid34267305, year = {2021}, author = {Ostadhossein, F and Moitra, P and Altun, E and Dutta, D and Sar, D and Tripathi, I and Hsiao, SH and Kravchuk, V and Nie, S and Pan, D}, title = {Function-adaptive clustered nanoparticles reverse Streptococcus mutans dental biofilm and maintain microbiota balance.}, journal = {Communications biology}, volume = {4}, number = {1}, pages = {846}, pmid = {34267305}, issn = {2399-3642}, support = {R03 EB028026/EB/NIBIB NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Female ; Humans ; Mice ; Microbial Viability/drug effects ; Microbiota/genetics/*physiology ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; NIH 3T3 Cells ; Nanoparticles/chemistry/*toxicity/ultrastructure ; Polymers/chemistry/*toxicity ; RNA, Ribosomal, 16S/genetics ; Rats, Sprague-Dawley ; Streptococcus mutans/*drug effects/growth & development/ultrastructure ; }, abstract = {Dental plaques are biofilms that cause dental caries by demineralization with acidogenic bacteria. These bacteria reside inside a protective sheath which makes any curative treatment challenging. We propose an antibiotic-free strategy to disrupt the biofilm by engineered clustered carbon dot nanoparticles that function in the acidic environment of the biofilms. In vitro and ex vivo studies on the mature biofilms of Streptococcus mutans revealed >90% biofilm inhibition associated with the contact-mediated interaction of nanoparticles with the bacterial membrane, excessive reactive oxygen species generation, and DNA fragmentation. An in vivo examination showed that these nanoparticles could effectively suppress the growth of S. mutans. Importantly, 16S rRNA analysis of the dental microbiota showed that the diversity and richness of bacterial species did not substantially change with nanoparticle treatment. Overall, this study presents a safe and effective approach to decrease the dental biofilm formation without disrupting the ecological balance of the oral cavity.}, } @article {pmid34265619, year = {2021}, author = {Huang, H and Yang, C and He, C and Hu, X and Hu, Z and Wang, W}, title = {Combining biofilm and membrane flocculation to enhance simultaneous nutrients removal and membrane fouling reduction.}, journal = {The Science of the total environment}, volume = {796}, number = {}, pages = {148922}, doi = {10.1016/j.scitotenv.2021.148922}, pmid = {34265619}, issn = {1879-1026}, mesh = {Biofilms ; *Bioreactors ; Flocculation ; *Nitrification ; Nitrogen ; Nutrients ; Phosphorus ; Sewage ; }, abstract = {The stability and processing capacity of membrane bioreactor can be improved with long sludge retention time. However, phosphorus removal will be markedly reduced under long sludge retention time and membrane fouling will be aggravated. Adding aluminum (Al) salt is a common way to achieve chemical phosphorus removal and membrane fouling reduction. But, accumulated Al will cause the decline of metabolic activity of activated sludge. In this study, biofilm-membrane flocculation reactor was proposed to enhance simultaneous nutrients removal and membrane fouling reduction. It showed that the removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH4[+]-N), total nitrogen (TN), and total phosphorus (TP) in biofilm-membrane flocculation reactor were 95.7%, 96.7%, 87.4%, and 97.2%, respectively. Compared with the control group, accumulated Al increased extracellular polymeric substances (EPS) secretion by 1.9%-35.4%, biofilm biomass by 12.4%-26.1%, and the activities of ammonia oxidation bacteria (AOB) and nitrite oxidation bacteria (NOB) in the biofilm increased by 42.9% and 65.9%, respectively. The relative abundance of Nitrospira, Dechloromonas, and Terrimonas in the biofilm increased by 1.78%, 3.01%, and 2.88%, respectively, which was conducive to facilitating the nitrification. Therefore, biofilm-membrane flocculation reactor is a promising way for enhancing simultaneous nutrients removal and membrane fouling reduction.}, } @article {pmid34265158, year = {2021}, author = {Dewangan, RP and Singh, M and Ilic, S and Tam, B and Akabayov, B}, title = {Cell-penetrating peptide conjugates of indole-3-acetic acid-based DNA primase/Gyrase inhibitors as potent anti-tubercular agents against planktonic and biofilm culture of Mycobacterium smegmatis.}, journal = {Chemical biology & drug design}, volume = {98}, number = {5}, pages = {722-732}, doi = {10.1111/cbdd.13925}, pmid = {34265158}, issn = {1747-0285}, support = {2016142//Bi-National Science Foundation/ ; 1023/18//Israel Science Foundation/ ; 59081//IMTI (TAMAT)/Israel Ministry of Industry - KAMIN Program/ ; }, mesh = {Antitubercular Agents/*chemistry/pharmacology ; Biofilms ; Cell-Penetrating Peptides/*chemistry ; DNA Primase/*chemistry/metabolism ; Indoleacetic Acids/*chemistry ; Microbial Sensitivity Tests ; Mycobacterium smegmatis/drug effects ; Plankton ; Topoisomerase II Inhibitors/*chemistry/metabolism ; }, abstract = {Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that caused 1.5 million fatalities globally in 2018. New strains of Mtb resistant to all known classes of antibiotics pose a global healthcare problem. In this work, we have conjugated novel indole-3-acetic acid-based DNA primase/gyrase inhibitor with cell-penetrating peptide via cleavable and non-cleavable bonds. For non-cleavable linkage, inhibitor was conjugated with peptide via an amide bond to the N-terminus, whereas a cleavable linkage was obtained by conjugating the inhibitor through a disulfide bond. We performed the conjugation of the inhibitor either directly on a solid surface or by using solution-phase chemistry. M. smegmatis (non-pathogenic model of Mtb) was used to determine the minimal inhibitory concentration (MIC) of the synthetic conjugates. Conjugates were found more active as compared to free inhibitor molecules. Strikingly, the conjugate also impairs the development of biofilm, showing a therapeutic potential against infections caused by both planktonic and sessile forms of mycobacterium species.}, } @article {pmid34264501, year = {2021}, author = {Brunetti, G and Giuliani, A and Navazio, AS and Paradisi, C and Raponi, F and Conti, LA and Raponi, G}, title = {Candida gut colonization, yeast species distribution, and biofilm production in Clostridioides difficile infected patients: a comparison between three populations in two different time periods.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {4}, pages = {1845-1852}, pmid = {34264501}, issn = {1678-4405}, mesh = {Biodiversity ; *Biofilms ; Candida/genetics ; Candida albicans/genetics ; *Candidiasis/complications/microbiology ; *Clostridioides difficile/genetics ; *Clostridium Infections/complications/microbiology ; *Gastrointestinal Microbiome ; Humans ; Phylogeny ; }, abstract = {Candida gut colonization and yeast biofilm production capacity were investigated, by means of XTT reduction assay, in Clostridioides difficile infected (CDI) patients, in non-CDI diarrheic patients, and in healthy donors in two different time periods (2013-2015 and 2018-2019 respectively). Candida gut colonization was significantly (p < 0.001) associated to C. difficile infection, and to patients infected with hypervirulent C. difficile strains bearing the tcdC deletion at nucleotide 117 (p = 0.0003). Although there was not a prevalent yeast species in CDI patients, C. albicans was the species significantly (p < 0.001) associated to both the infections sustained by the non-hypervirulent C. difficile strains and those caused by the hypervirulent strain (p = 0.001). The biofilm production by the yeasts isolated from the CDI patients and from non-CDI diarrheic patients did not differ significantly. However, a significantly (p = 0.007) higher biofilm production was observed in the Candida strains, particularly C. albicans, isolated from healthy donors compared to that of the yeasts cultured from CDI patients. Seasonal occurrence was observed in the isolation rate of CDI and non-CDI diarrheic cases (p = 0.0019), peaking in winter for CDI patients and in spring for non-CDI diarrheic patients. Furthermore, seasonality emerged in the gut colonization by Candida of CDI patients in the winter. It seems, therefore, that the reduced capacity of biofilm production by Candida strains isolated from CDI patients might have a role in the development of C. difficile infection, probably facilitating the spread of the bacteria into the gut thus amplifying their pathogenic action.}, } @article {pmid34264471, year = {2021}, author = {Chapman, JE and Olson, ME}, title = {Human Skin In Vitro Colonization Model for a Skin Wound Infected by Staphylococcus aureus Biofilm.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2341}, number = {}, pages = {153-159}, pmid = {34264471}, issn = {1940-6029}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial ; Humans ; Microbial Viability ; Models, Biological ; Skin/microbiology ; Staphylococcus aureus/drug effects/*pathogenicity ; Wound Infection/*microbiology ; }, abstract = {Biofilms provide an environment in which bacteria can survive adverse conditions such as nutrient or oxygen deficiencies, and antibiotic treatments. Bacterial survival of antibiotic treatments can often result in antimicrobial resistance, which can make treating infections substantially more difficult, increase the burden of healthcare costs, and hinder the healing of infected wounds. As Staphylococcus aureus is a bacterium that commonly causes skin infections, can be found in infected skin wounds, and is prone to developing antimicrobial resistance-especially within a biofilm microenvironment, the study and development of methodologies to treat infected wounds have become an important topic of research. To study the development of bacterial biofilm in a skin wound, this chapter discusses an in vitro model to access biofilm growth in an environment that mimics a human skin wound. This model serves as a tool to study the biofilm growth and efficacy of antibiotic use in an in vitro system that more closely resembles human skin tissue, rather than a polystyrene plate.}, } @article {pmid34264467, year = {2021}, author = {Lei, MG and Gupta, RK and Lee, CY}, title = {A Rat Model of Orthopedic Implant-Associated Infection for Identification of Staphylococcal Biofilm Proteins.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2341}, number = {}, pages = {117-125}, pmid = {34264467}, issn = {1940-6029}, mesh = {Animals ; Bacterial Proteins/*isolation & purification ; Biofilms/*growth & development ; Chromatography, Liquid ; Disease Models, Animal ; Male ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/*microbiology ; Rats ; Staphylococcal Infections/*diagnosis ; Staphylococcus aureus/metabolism/*physiology ; Tandem Mass Spectrometry ; }, abstract = {Secreted bacterial proteins are difficult to identify directly from an infection site due to a limited amount of bacteria and presence of a large quantity of host proteins. Here we describe a rat model of orthopedic implant that allows us to harvest bacterial biofilm materials sufficient for identification of bacterial proteins in the biofilm matrix by liquid chromatography-tandem MS (GeLC-MS/MS) analysis.}, } @article {pmid34264462, year = {2021}, author = {Grossman, AB and Burgin, DJ and Rice, KC}, title = {Quantification of Staphylococcus aureus Biofilm Formation by Crystal Violet and Confocal Microscopy.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2341}, number = {}, pages = {69-78}, pmid = {34264462}, issn = {1940-6029}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; Gentian Violet/*pharmacology ; Microscopy, Confocal ; Spectrophotometry ; Staphylococcus aureus/*physiology ; }, abstract = {Most Staphylococcus aureus strains can grow as a multicellular biofilm, a phenotype of utmost importance to clinical infections such as endocarditis, osteomyelitis, and implanted medical device infection. As biofilms are inherently more tolerant to the host immune system and antibiotics, understanding the S. aureus genes and regulatory circuits that contribute to biofilm development is an active and on-going field of research. This chapter details a high-throughput and standardized way to grow S. aureus biofilms using a classical microtiter plate assay. Biofilms can be quantified using crystal violet or by confocal microscopy imaging and COMSTAT analysis.}, } @article {pmid34264102, year = {2021}, author = {Testerman, T and Reichley, SR and King, S and Graf, J}, title = {Draft Genome Sequence of Janthinobacterium lividum ID1246, Isolated from a Rainbow Trout Hatchery Biofilm.}, journal = {Microbiology resource announcements}, volume = {10}, number = {28}, pages = {e0044421}, pmid = {34264102}, issn = {2576-098X}, support = {8082-32000-006-00-D//U.S. Department of Agriculture (USDA)/ ; }, abstract = {We present a draft genome sequence of Janthinobacterium lividum strain ID1246, isolated from within a rainbow trout hatchery raceway. Janthinobacterium spp. are well-known producers of antimicrobial compounds. Due to the unique isolation source, this genome may yield novel biosynthetic gene clusters.}, } @article {pmid34263993, year = {2022}, author = {Bounds, K and Colmer-Hamood, JA and Myntti, M and Jeter, RM and Hamood, AN}, title = {The influence of a biofilm-dispersing wound gel on the wound healing process.}, journal = {International wound journal}, volume = {19}, number = {3}, pages = {553-572}, pmid = {34263993}, issn = {1742-481X}, support = {//Next Science, LLC; Jacksonville, Florida, USA/ ; }, mesh = {Animals ; *Anti-Infective Agents, Local/pharmacology ; Biofilms ; Gels ; Mice ; Skin/injuries ; Wound Healing ; *Wound Infection/drug therapy ; }, abstract = {Topical antimicrobials that reduce the bacterial bioburden within a chronically-infected wound may have helpful or harmful effects on the healing process. We used murine models of full-thickness skin wounds to determine the effects of the novel biofilm-dispersing wound gel (BDWG) and its gel base on the healing of uninfected wounds. The rate of wound closure over 19 days was comparable among the BDWG-treated (BT) wounds and the controls. Compared with the controls, histology of the BT wounds showed formation of a stable blood clot at day 1, more neovascularisation and reepithelialisation at day 3, and more organised healing at day 7. Fluorescence-activated cell sorting analysis showed a lower percentage of neutrophils in wounded tissues of the BT group at days 1 and 3, and significantly more M2 macrophages at day 3. Levels of proinflammatory cytokines and chemokines were increased over the uninjured baseline within the wounds of all treatment groups but the levels were significantly lower in the BT group at day 1, modulating the inflammatory response. Our results suggest that BDWG does not interfere with the wound healing process and may enhance it by lowering inflammation and allowing transition to the proliferative stage of wound healing by day 3.}, } @article {pmid34262845, year = {2021}, author = {Qi, X and Brothers, KM and Ma, D and Mandell, JB and Donegan, NP and Cheung, AL and Richardson, AR and Urish, KL}, title = {The Staphylococcus aureus toxin-antitoxin system YefM-YoeB is associated with antibiotic tolerance and extracellular dependent biofilm formation.}, journal = {Journal of bone and joint infection}, volume = {6}, number = {7}, pages = {241-253}, pmid = {34262845}, issn = {2206-3552}, support = {K08 AR071494/AR/NIAMS NIH HHS/United States ; KL2 TR001856/TR/NCATS NIH HHS/United States ; }, abstract = {The high antibiotic tolerance of Staphylococcus aureus biofilms is associated with challenges for treating periprosthetic joint infection. The toxin-antitoxin system, YefM-YoeB, is thought to be a regulator for antibiotic tolerance, but its physiological role is unknown. The objective of this study was to determine the biofilm and antibiotic susceptibility phenotypes associated with S. aureus yoeB homologs. We hypothesized the toxin-antitoxin yoeB homologs contribute to biofilm formation and antibiotic susceptibility. Disruption of yoeB1 and yoeB2 resulted in decreased biofilm formation in comparison to Newman and JE2 wild-type (WT) S. aureus strains. In comparison to yoeB mutants, both Newman and JE2 WT strains had higher polysaccharide intercellular adhesin (PIA) production. Treatment with sodium metaperiodate increased biofilm formation in Newman WT, indicating biofilm formation may be increased under conditions of oxidative stress. DNase I treatment decreased biofilm formation in Newman WT but not in the absence of yoeB1 or yoeB2. Additionally, WT strains had a higher extracellular DNA (eDNA) content in comparison to yoeB mutants but no differences in biofilm protein content. Moreover, loss of yoeB1 and yoeB2 decreased biofilm survival in both Newman and JE2 strains. Finally, in a neutropenic mouse abscess model, deletion of yoeB1 and yoeB2 resulted in reduced bacterial burden. In conclusion, our data suggest that yoeB1 and yoeB2 are associated with S. aureus planktonic growth, extracellular dependent biofilm formation, antibiotic tolerance, and virulence.}, } @article {pmid34262542, year = {2021}, author = {Li, M and Shu, C and Ke, W and Li, X and Yu, Y and Guan, X and Huang, T}, title = {Plant Polysaccharides Modulate Biofilm Formation and Insecticidal Activities of Bacillus thuringiensis Strains.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {676146}, pmid = {34262542}, issn = {1664-302X}, abstract = {After the biological pesticide Bacillus thuringiensis (Bt) is applied to the field, it has to remain on the surface of plants to have the insecticidal activities against insect pests. Bt can form biofilms on the surface of vegetable leaves, which were rich in polysaccharides. However, the relationship between polysaccharides of the leaves and the biofilm formation as well as the insecticidal activities of Bt is still unknown. Herein, this study focused on the effects of plant polysaccharides pectin and xylan on biofilm formation and the insecticidal activities of Bt strains. By adding pectin, there were 88 Bt strains with strong biofilm formation, 69 strains with weak biofilm formation, and 13 strains without biofilm formation. When xylan was added, 13 Bt strains formed strong biofilms, 98 strains formed weak biofilms, and 59 strains did not form biofilms. This indicated that two plant polysaccharides, especially pectin, modulate the biofilm formation of Bt strains. The ability of pectin to induce biofilm formation was not related to Bt serotypes. Pectin promoted the biofilms formed by Bt cells in the logarithmic growth phase and lysis phase at the air-liquid interface, while it inhibited the biofilms formed by Bt cells in the sporangial phase at the air-liquid interface. The dosage of pectin was positively correlated with the yield of biofilms formed by Bt cells in the logarithmic growth phase or lysis phase at the solid-liquid interfaces. Pectin did not change the free-living growth and the cell motility of Bt strains. Pectin can improve the biocontrol activities of the spore-insecticidal crystal protein mixture of Bt and BtK commercial insecticides, as well as the biofilms formed by the logarithmic growth phase or lysis phase of Bt cells. Our findings confirmed that plant polysaccharides modulate biofilm formation and insecticidal activities of Bt strains and built a foundation for the construction of biofilm-type Bt biopesticides.}, } @article {pmid34262306, year = {2021}, author = {Li, Z and Ding, Z and Liu, Y and Jin, X and Xie, J and Li, T and Zeng, Z and Wang, Z and Liu, J}, title = {Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {2613-2624}, pmid = {34262306}, issn = {1178-6973}, abstract = {BACKGROUND: Acinetobacter baumannii is an important pathogen in clinical infections, and biofilm formation is an effective way for A. baumannii to survive under external pressures. In this study, the aims were to examine the antimicrobial resistance, biofilm formation, and biofilm-specific resistance in clinical isolates of A. baumannii.

MATERIALS AND METHODS: A total of 104 clinical A. baumannii isolates were collected from a large teaching hospital in Southwest China. The antibiotics susceptibilities were tested, and biofilm-forming ability was evaluated by crystal violet staining by confocal laser scanning microscopy (CLSM). Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC) of ciprofloxacin, meropenem, and ceftazidime were tested on selected strains by broth microdilution method. Biofilm-associated genes were detected by polymerase chain reaction (PCR), and expression of genes at planktonic stage and biofilm stage were analyzed by real-time reverse transcription PCR (RT-PCR).

RESULTS: Multidrug-resistant (MDR) isolates accounted for 65.4%, but no strain was resistant to tigecycline and polymyxin B. Moreover, non-MDR strains tended to form stronger biofilms than MDR strains, and a negative correlation between biofilm-forming ability and resistance profiles to each of tested antimicrobials were observed. The MBECs and MBICs of ciprofloxacin, ceftazidime, and meropenem were evidently increased compared with MICs and MBCs among all tested strains. Additionally, the biofilm formation ability of the csuD-positive strains was stronger than that of the csuD-negative strains. The strains in MDR group had higher carrying rate of csuA and csuD genes than non-MDR group, while non-MDR strains possessed more ompA gene than MDR group. Finally, abaI gene was significantly up-regulated after biofilm formation.

CONCLUSION: These results revealed valuable data for the negative correlation between antimicrobial resistance and biofilm formation, as well as phenotypic and genotypic characteristics of biofilm formation in A. baumannii.}, } @article {pmid34260396, year = {2021}, author = {Koeppen, K and Nymon, A and Barnaby, R and Bashor, L and Li, Z and Hampton, TH and Liefeld, AE and Kolling, FW and LaCroix, IS and Gerber, SA and Hogan, DA and Kasetty, S and Nadell, CD and Stanton, BA}, title = {Let-7b-5p in vesicles secreted by human airway cells reduces biofilm formation and increases antibiotic sensitivity of P. aeruginosa.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {118}, number = {28}, pages = {}, pmid = {34260396}, issn = {1091-6490}, support = {P20 GM113132/GM/NIGMS NIH HHS/United States ; R01 HL151385/HL/NHLBI NIH HHS/United States ; R01 AI081838/AI/NIAID NIH HHS/United States ; P30 CA023108/CA/NCI NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; R25 HG011447/HG/NHGRI NIH HHS/United States ; }, mesh = {Antagomirs/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Aztreonam/pharmacology ; Biofilms/drug effects/*growth & development ; Extracellular Vesicles/drug effects/*metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; MicroRNAs/genetics/*metabolism ; Plankton/drug effects ; Pseudomonas aeruginosa/drug effects/genetics/isolation & purification/*physiology ; beta-Lactams/pharmacology ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that forms antibiotic-resistant biofilms, which facilitate chronic infections in immunocompromised hosts. We have previously shown that P. aeruginosa secretes outer-membrane vesicles that deliver a small RNA to human airway epithelial cells (AECs), in which it suppresses the innate immune response. Here, we demonstrate that interdomain communication through small RNA-containing membrane vesicles is bidirectional and that microRNAs (miRNAs) in extracellular vesicles (EVs) secreted by human AECs regulate protein expression, antibiotic sensitivity, and biofilm formation by P. aeruginosa Specifically, human EVs deliver miRNA let-7b-5p to P. aeruginosa, which systematically decreases the abundance of proteins essential for biofilm formation, including PpkA and ClpV1-3, and increases the ability of beta-lactam antibiotics to reduce biofilm formation by targeting the beta-lactamase AmpC. Let-7b-5p is bioinformatically predicted to target not only PpkA, ClpV1, and AmpC in P. aeruginosa but also the corresponding orthologs in Burkholderia cenocepacia, another notorious opportunistic lung pathogen, suggesting that the ability of let-7b-5p to reduce biofilm formation and increase beta-lactam sensitivity is not limited to P. aeruginosa Here, we provide direct evidence for transfer of miRNAs in EVs secreted by eukaryotic cells to a prokaryote, resulting in subsequent phenotypic alterations in the prokaryote as a result of this interdomain communication. Since let-7-family miRNAs are in clinical trials to reduce inflammation and because chronic P. aeruginosa lung infections are associated with a hyperinflammatory state, treatment with let-7b-5p and a beta-lactam antibiotic in nanoparticles or EVs may benefit patients with antibiotic-resistant P. aeruginosa infections.}, } @article {pmid34259620, year = {2021}, author = {da Rocha, LF and Pippi, B and Joaquim, AR and de Andrade, SF and Fuentefria, AM}, title = {8-hydroxyquinoline-5-(N-4-chlorophenyl) sulfonamide and fluconazole combination as a preventive strategy for Candida biofilm in haemodialysis devices.}, journal = {Journal of medical microbiology}, volume = {70}, number = {7}, pages = {}, doi = {10.1099/jmm.0.001377}, pmid = {34259620}, issn = {1473-5644}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/classification/*drug effects/physiology ; Candidiasis/microbiology ; Equipment Contamination/*prevention & control ; Fluconazole/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Oxyquinoline/pharmacology ; Renal Dialysis ; Sulfonamides/*pharmacology ; }, abstract = {Introduction. The presence of Candida biofilms in medical devices is a concerning and important clinical issue for haemodialysis patients who require constant use of prosthetic fistulae and catheters.Hypothesis/Gap Statement. This prolonged use increases the risk of candidaemia due to biofilm formation. PH151 and clioquinol are 8-hydroxyquinoline derivatives that have been studied by our group and showed interesting anti-Candida activity.Aim. This study evaluated the biofilm formation capacity of Candida species on polytetrafluoroethylene (PTFE) and polyurethane (PUR) and investigated the synergistic effects between the compounds PH151 and clioquinol and fluconazole, amphotericin B and caspofungin against biofilm cells removed from those materials. Further, the synergistic combination was evaluated in terms of preventing biofilm formation on PTFE and PUR discs.Methodology. Susceptibility testing was performed for planktonic and biofilm cells using the broth microdilution method. The checkerboard method and the time-kill assay were used to evaluate the interactions between antifungal agents. Antibiofilm activity on PTFE and PUR materials was assessed to quantify the prevention of biofilm formation.Results. Candida albicans, Candida glabrata and Candida tropicalis showed ability to form biofilms on both materials. By contrast, Candida parapsilosis did not demonstrate this ability. Synergistic interaction was observed when PH151 was combined with fluconazole in 77.8 % of isolates and this treatment was shown to be concentration- and time-dependent. On the other hand, indifferent interactions were predominantly observed with the other combinations. A reduction in biofilm formation on PUR material of more than 50 % was observed when using PH151 combined with fluconazole.Conclusion. PH151 demonstrated potential as a local treatment for use in a combination therapy approach against Candida biofilm formation on haemodialysis devices.}, } @article {pmid34258578, year = {2021}, author = {Shariq, AF and Beyenal, H and Akin, ID}, title = {Biofilm addition improves sand strength over a wide range of saturations.}, journal = {Biofilm}, volume = {3}, number = {}, pages = {100050}, pmid = {34258578}, issn = {2590-2075}, abstract = {Bio-mediated ground improvement is an attractive alternative to traditional admixtures for strength improvement of shallow surfaces because it is environmentally friendly. Since biofilms contain extracellular polymeric substances (EPS), they can be considered as an alternative to current technologies to improve soil strength. EPS containing biofilms are porous materials with charged surfaces, and therefore adsorption and capillary condensation can result in water retention. Currently, most of the literature work only tested soil improvement under the dry condition. Therefore, the influence of water retention by biofilms on the strength of improved soil remains unclear. Our goal is to evaluate the strength of a biofilm-enhanced sand over a wide range of saturations and explain the trends through the suction stress characteristic curve (SSCC), which quantifies interparticle adsorptive, capillary, and cementation forces as a function of saturation. We used homogenized anaerobic granule biofilms from an existing upflow anaerobic sludge blanket reactor and mixed it with sand to test the strength of a poorly-graded sand in a wide range of saturations, S (between 0.02 S and 0.74 S). We found that biofilm treatment of sand increases soil strength through cementation over a wide range of saturations and through adsorptive forces among sand, biofilm surfaces, and water molecules at low saturations (S < ~0.3). Our results suggested that homogenized biofilms mixed with sand can be used to improve the strength of sand over a wide range of saturations.}, } @article {pmid34257170, year = {2021}, author = {Subbiya, A and Gayathri, K and Venkatesh, A and Padmavathy, K and Mahalakshmi, K and Mitthra, S}, title = {Evaluation of the Antibacterial Efficacy of Daptomycin, Gentamicin, and Calcium Hydroxide-Antibiotic Combinations on Enterococcus faecalis Dentinal Biofilm: An In Vitro Study.}, journal = {The journal of contemporary dental practice}, volume = {22}, number = {2}, pages = {128-133}, pmid = {34257170}, issn = {1526-3711}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Calcium Hydroxide/pharmacology ; *Daptomycin/pharmacology ; Dental Pulp Cavity ; Dentin ; Enterococcus faecalis ; Gentamicins/pharmacology ; Root Canal Irrigants ; }, abstract = {AIM: To evaluate the antibacterial efficacy of calcium hydroxide (CH) with antibiotic combinations: daptomycin and gentamicin against Enterococcus faecalis (E. faecalis) dentinal biofilm.

MATERIALS AND METHODS: Sixty freshly extracted single-rooted mandibular premolars were inoculated with E. faecalis(ATCC 29212) (n = 30) (group A) and clinical isolates (n = 30) (group B) for 3 weeks to form a biofilm. The tooth samples of groups A and B were randomly divided into three subgroups of 10 each, groups 1A and 1B (CH), groups 2A and 2B (CH+G), groups 3A and 3B (CH+D), depending on the medicaments to be placed for one week. The difference between initial and final CFU was calculated and statistically analyzed.

RESULTS: Among the clinical isolates, CH-antibiotic combinations were more effective than CH alone, which was statistically significant (p = 0.006).

CONCLUSION: The dentinal biofilm of clinical isolates of E. faecalis strains exhibited more reduction in bacterial colonies with CH in combination with antibiotics (D and G).

CLINICAL SIGNIFICANCE: Daptomycin and gentamicin when used as an intra-canal medicament in combination with CH are effective in eliminating E. faecalis. Keywords: Calcium hydroxide, Daptomycin, Dentinal biofilm, E. faecalis, Gentamicin.}, } @article {pmid34256585, year = {2021}, author = {Kim, H and Aquino, M and Izadjoo, M}, title = {Development and assessment of a high-throughput biofilm and biomass testing platform.}, journal = {Journal of wound care}, volume = {30}, number = {Sup7}, pages = {S36-S46}, doi = {10.12968/jowc.2021.30.Sup7.S36}, pmid = {34256585}, issn = {0969-0700}, mesh = {*Anti-Bacterial Agents ; Biofilms ; Biomass ; Humans ; Pseudomonas aeruginosa ; *Wound Infection ; }, abstract = {OBJECTIVE: To develop and evaluate a simple platform technology for developing static biofilms in a 96-well microtitre plate for various downstream applications. The technology allows monitoring of growth rate, biofilm formation and quantifying biofilm biomass by using crystal violet (CV) and safranin O (SO) staining over seven-day time periods for pathogens including clinical isolates most commonly associated with hard-to-treat wound infections.

METHOD: A total of 157 bacteria including Acinetobacter, Enterobacter, Klebsiella, Pseudomonas and Staphylococcus spp. were used in the study. Bacterial growth was measured at 600nm optical density (OD). Biofilm formation was monitored and assessed quantitatively with CV at 570nm and SO staining at 492nm for one-, two-, three- and seven-day incubation periods.

RESULTS: Bacterial growth rate and static biofilm biomass in the 96-well plates varied for various strains tested. Both CV and SO staining showed similar results in the biomass, with SO assay displaying more reproducible data throughout the study. Most of the strains were metabolically active even at the seven-day incubation period. Microbial adherences of all bacterial strains on the plastic surface was assessed with CV staining: 28 Acinetobacter, 17 Staphylococcus, 12 Pseudomonas and four Enterobacter strains were strong biofilm producers. Moderate biofilm-producing strains included 27 Staphylococcus, 14 Acinetobacter, eight Pseudomonas and three Enterobacter. Weak biofilm-producing strains included: 33 Staphylococcus, six Enterobacter, two Pseudomonas and one Acinetobacter. Only one Pseudomonas aeruginosa strain did not develop biofilm.

CONCLUSION: Our results demonstrate the feasibility of using 96-well microtitre plates as a high-throughput platform for quantitative measurement and assessment of biofilm development over time. Studying microbial adherence or biofilm biomass generated on various surfaces using a high-throughput system could provide valuable information for in vitro testing and developing therapeutics for biofilm infections. Employing the biofilm testing platform described in this study makes it possible to simultaneously develop different biofilms formed by specific pathogens, and study potential association between the quantity of bacterial biomass and strength of a biofilm formed by specific wound pathogens. In addition, the described testing approach could provide an optimal model for standardised and high-throughput screening of candidate antibiofilm therapeutics.}, } @article {pmid34256291, year = {2021}, author = {Zhang, Y and Zhang, Y and Liu, L and Zhou, L and Zhao, Z}, title = {Impacts of antibiotics on biofilm bacterial community and disinfection performance on simulated drinking water supply pipe wall.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {288}, number = {}, pages = {117736}, doi = {10.1016/j.envpol.2021.117736}, pmid = {34256291}, issn = {1873-6424}, mesh = {Angiotensin Receptor Antagonists ; Angiotensin-Converting Enzyme Inhibitors ; Anti-Bacterial Agents ; Bacteria/genetics ; Biofilms ; Disinfection ; *Drinking Water/analysis ; Genes, Bacterial ; Water Supply ; }, abstract = {Overuse of antibiotics is accelerating the spread of resistance risk in the environment. In drinking water supply systems, the effect of antibiotics on the resistance of biofilm is unclear, and there have been few studies in disinfectant-containing systems. Here, we designed a series of drinking water supply reactors to investigate the effects of antibiotics on biofilm and bacteria in the water. At low concentrations, antibiotics could promote the growth of bacteria in biofilm; among the tested antibiotics (tetracycline, sulfadiazine and chloramphenicol), tetracycline had the strongest ability to promote this. And the antibiotic resistant bacteria (ARB) could inhibit the growth of bacteria in drinking water. Results have shown that antibiotics enhanced the bacterial chlorine resistance in the effluent, but reduced that in the biofilm. Furthermore, metagenomic analysis showed that antibiotics reduced the richness of biofilm communities. The dominant phyla in the biofilm were Proteobacteria, Planctomycetes, and Firmicutes. In tetracycline-treated biofilm, the dominant phylum was Planctomycetes. In sulfadiazine- and chloramphenicol-treated groups, bacteria with complex cell structures preferentially accumulated. The dominant class in biofilm in the ARB-added group was Gammaproteobacteria. The abundance of antibiotic resistant genes (ARGs) was correlated with biofilm community structure. This study shows that antibiotics make the biofilm community structure of drinking water more resistant to chlorine. ARGs may be selective for certain bacteria in the process, and there may ultimately be enhanced chlorine and antibiotic resistance of effluent bacteria in drinking water.}, } @article {pmid34256119, year = {2021}, author = {Ikeda, K and Shoda, T and Demizu, Y and Tsuji, G}, title = {Discovery of non-proteinogenic amino acids inhibiting biofilm formation by S. aureus and methicillin-resistant S. aureus.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {48}, number = {}, pages = {128259}, doi = {10.1016/j.bmcl.2021.128259}, pmid = {34256119}, issn = {1464-3405}, mesh = {Amino Acids/chemical synthesis/chemistry/*pharmacology ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; *Drug Discovery ; Microbial Sensitivity Tests ; Molecular Structure ; Staphylococcus aureus/*drug effects ; Structure-Activity Relationship ; }, abstract = {Bacterial biofilms often cause medical complications and there has been a great deal of interest in the discovery of small-molecule agents that can inhibit the formation of biofilms. Among these agents, it has been reported that several d-amino acids, such as d-Leu, d-Trp, d-Tyr, and d-Met, exhibit weak inhibitory activity toward bacterial biofilm formation. In this study, we have screened a library of 332 non-proteinogenic amino acids for new biofilm inhibitory agents and discovered several compounds exhibiting biofilm-inhibitory activity against Gram-positive bacteria. In particular, H-DL-β-(3,4-dihydroxyphenyl)-dl-Ser-OH (253) showed potent activity against S. aureus, including methicillin-resistant S. aureus.}, } @article {pmid34251364, year = {2021}, author = {Buttaro, B and Queisser, G}, title = {A Bead Movement Based Computational Framework for 3-Dimensional Analysis of Biofilm Material Heterogeneity.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {172}, pages = {}, doi = {10.3791/62454}, pmid = {34251364}, issn = {1940-087X}, mesh = {*Bacterial Proteins ; *Biofilms ; Enterococcus faecalis ; Escherichia coli ; Salmonella typhimurium ; }, abstract = {Differences in the material properties of bacterial biofilms have been observed in biofilms of different bacterial species, within the same species under different growth conditions and after treatment with matrix modifying molecules. To better quantitate the material properties of 3D biofilms, an experimental and computational workflow was developed and applied to examine differences between Enterococcus faecalis, Salmonella enterica serotype Typhimurium and Escherichia coli biofilms as well as the role of the amyloid curli in confirming rigidity to Enterobacteriaceae biofilms. The spatio-temporal dynamics of 1 µm carboxylate beads in biofilms were tracked in 20 µm 3D biofilms over 20 minutes. The 4D image stacks were processed using the Mosaic plugin in ImageJ to produce 3D trajectory data of bead movement. This trajectory data was analyzed with a newly developed Bead Evaluator toolbox, where movement data, including trajectory lifespans, bead velocities, cell densities along trajectories, and bounding box information were computed and stored in csv-files. This paper presents the workflow from experimental setup and image recording to bead trajectory computation and analysis. The structure of curli-containing biofilms resulted in more stable bead interactions and less bead movement than in curli-mutant and Enterococcal biofilms. Bead movement did not appear strongly dependent on cell density when measuring the bead velocity and trajectory bounding box volume, supporting the hypothesis that other material properties of the biofilms control the bead dynamics. This technique is widely applicable to quantitating differences in biofilms of different matrix compositions as well as biofilms before and after matrix-modifying treatments.}, } @article {pmid34249887, year = {2021}, author = {Woitschach, F and Kloss, M and Schlodder, K and Rabes, A and Mörke, C and Oschatz, S and Senz, V and Borck, A and Grabow, N and Reisinger, EC and Sombetzki, M}, title = {The Use of Zwitterionic Methylmethacrylat Coated Silicone Inhibits Bacterial Adhesion and Biofilm Formation of Staphylococcus aureus.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {686192}, pmid = {34249887}, issn = {2296-4185}, abstract = {In recent decades, biofilm-associated infections have become a major problem in many medical fields, leading to a high burden on patients and enormous costs for the healthcare system. Microbial infestations are caused by opportunistic pathogens which often enter the incision already during implantation. In the subsequently formed biofilm bacteria are protected from the hosts immune system and antibiotic action. Therefore, the development of modified, anti-microbial implant materials displays an indispensable task. Thermoplastic polyurethane (TPU) represents the state-of-the-art material in implant manufacturing. Due to the constantly growing areas of application and the associated necessary adjustments, the optimization of these materials is essential. In the present study, modified liquid silicone rubber (LSR) surfaces were compared with two of the most commonly used TPUs in terms of bacterial colonization and biofilm formation. The tests were conducted with the clinically relevant bacterial strains Staphylococcus aureus and Staphylococcus epidermidis. Crystal violet staining and scanning electron microscopy showed reduced adhesion of bacteria and thus biofilm formation on these new materials, suggesting that the investigated materials are promising candidates for implant manufacturing.}, } @article {pmid34248911, year = {2021}, author = {Yu, J and Jiang, F and Zhang, F and Hamushan, M and Du, J and Mao, Y and Wang, Q and Han, P and Tang, J and Shen, H}, title = {Thermonucleases Contribute to Staphylococcus aureus Biofilm Formation in Implant-Associated Infections-A Redundant and Complementary Story.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {687888}, pmid = {34248911}, issn = {1664-302X}, abstract = {Biofilms formed by Staphylococcus aureus are one of the predominant causes of implant-associated infections (IAIs). Previous studies have found that S. aureus nucleases nuc1 and nuc2 modulate biofilm formation. In this study, we found low nuc1/nuc2 expression and high biofilm-forming ability among IAI isolates. Furthermore, in a mouse model of exogenous IAIs, Δnuc1/2 exhibited higher bacterial load on the surface of the implant than that exhibited by the other groups (WT, Δnuc1, and Δnuc2). Survival analysis of the hematogenous IAI mouse model indicated that nuc1 is a virulence factor related to mortality. We then detected the influence of nuc1 and nuc2 on biofilm formation and immune evasion in vitro. Observation of in vitro biofilm structures with scanning electron microscopy and evaluation of bacterial aggregation with flow cytometry revealed that both nuc1 and nuc2 are involved in biofilm structuring and bacterial aggregation. Unlike nuc1, which is reported to participate in immune evasion, nuc2 cannot degrade neutrophil extracellular traps. Moreover, we found that nuc1/nuc2 transcription is negatively correlated during S. aureus growth, and a possible complementary relationship has been proposed. In conclusion, nuc1/nuc2 are complementary genes involved in biofilm formation in exogenous IAIs. However, nuc2 contributes less to virulence and is not involved in immune evasion.}, } @article {pmid34248907, year = {2021}, author = {Bhagwat, G and O'Connor, W and Grainge, I and Palanisami, T}, title = {Understanding the Fundamental Basis for Biofilm Formation on Plastic Surfaces: Role of Conditioning Films.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {687118}, pmid = {34248907}, issn = {1664-302X}, abstract = {Conditioning films (CFs) are surface coatings formed by the adsorption of biomolecules from the surrounding environment that can modify the material-specific surface properties and precedes the attachment of microorganisms. Hence, CFs are a biologically relevant identity that could govern the behavior and fate of microplastics in the aquatic environment. In the present study, polyethylene terephthalate (PET) and polylactic acid (PLA) plastic cards were immersed in natural seawater to allow the formation of CFs. The changes in the surface roughness after 24 h were investigated by atomic force microscopy (AFM), and the surface changes were visualized by scanning electron microscopy (SEM). The global elemental composition of the conditioned surface was investigated by energy dispersive spectroscopy (EDS). Results indicated that marine conditioning of PET and PLA samples for 24 h resulted in an increase of ∼11 and 31% in the average surface roughness, respectively. SEM images revealed the attachment of coccoid-shaped bacterial cells on the conditioned surfaces, and the accumulation of salts of sodium and phosphate-containing precipitates was revealed through the EDS analysis. The results indicate that the increase in surface roughness due to conditioning is linked to a material's hydrophilicity leading to a rapid attachment of bacteria on the surfaces. Further investigations into the CFs can unfold crucial knowledge surrounding the plastic-microbe interaction that has implications for medical, industrial, and environmental research.}, } @article {pmid34248894, year = {2021}, author = {Hwang, SH and Im, H and Choi, SH}, title = {A Master Regulator BrpR Coordinates the Expression of Multiple Loci for Robust Biofilm and Rugose Colony Development in Vibrio vulnificus.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {679854}, pmid = {34248894}, issn = {1664-302X}, abstract = {Vibrio vulnificus, a fulminating human pathogen, forms biofilms to enhance its survival in nature and pathogenicity during host infection. BrpR is the transcriptional regulator governing robust biofilm and rugose colony formation in V. vulnificus, but little is known about both the direct regulon of BrpR and the role of BrpR in regulation of downstream genes. In this study, transcript analyses revealed that BrpR is highly expressed and thus strongly regulates the downstream gene in the stationary and elevated cyclic di-GMP conditions. Transcriptome analyses discovered the genes, whose expression is affected by BrpR but not by the downstream regulator BrpT. Two unnamed adjacent genes (VV2_1626-1627) were newly identified among the BrpR regulon and designated as brpL and brpG in this study. Genetic analyses showed that the deletion of brpL and brpG impairs the biofilm and rugose colony formation, indicating that brpLG plays a crucial role in the development of BrpR-regulated biofilm phenotypes. Comparison of the colony morphology and exopolysaccharide (EPS) production suggested that although the genetic location and regulation of brpLG are distinct from the brp locus, brpABCDFHIJK (VV2_1574-1582), brpLG is also responsible for the robust EPS production together with the brp locus genes. Electrophoretic mobility shift assays and DNase I protection assays demonstrated that BrpR regulates the expression of downstream genes in distinct loci by directly binding to their upstream regions, revealing a palindromic binding sequence. Altogether, this study suggests that BrpR is a master regulator coordinating the expression of multiple loci responsible for EPS production and thus, contributing to the robust biofilm and rugose colony formation of V. vulnificus.}, } @article {pmid34248879, year = {2021}, author = {Ellepola, K and Huang, X and Riley, RP and Bitoun, JP and Wen, ZT}, title = {Streptococcus mutans Lacking sufCDSUB Is Viable, but Displays Major Defects in Growth, Stress Tolerance Responses and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {671533}, pmid = {34248879}, issn = {1664-302X}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; }, abstract = {Streptococcus mutans appears to possess a sole iron-sulfur (Fe-S) cluster biosynthesis system encoded by the sufCDSUB cluster. This study was designed to examine the role of sufCDSUB in S. mutans physiology. Allelic exchange mutants deficient of the whole sufCDSUB cluster and in individual genes were constructed. Compared to the wild-type, UA159, the sufCDSUB-deficient mutant, Δsuf::kan [r] , had a significantly reduced growth rate, especially in medium with the absence of isoleucine, leucine or glutamate/glutamine, amino acids that require Fe-S clusters for biosynthesis and when grown with medium adjusted to pH 6.0 and under oxidative and nitrosative stress conditions. Relative to UA159, Δsuf::kan [r] had major defects in stress tolerance responses with reduced survival rate of > 2-logs following incubation at low pH environment or after hydrogen peroxide challenge. When compared to UA159, Δsuf::kan [r] tended to form aggregates in broth medium and accumulated significantly less biofilm. As shown by luciferase reporter fusion assays, the expression of sufCDSUB was elevated by > 5.4-fold when the reporter strain was transferred from iron sufficient medium to iron-limiting medium. Oxidative stress induced by methyl viologen increased sufCDSUB expression by > 2-fold, and incubation in a low pH environment led to reduction of sufCDSUB expression by > 7-fold. These results suggest that lacking of SufCDSUB in S. mutans causes major defects in various cellular processes of the deficient mutant, including growth, stress tolerance responses and biofilm formation. In addition, the viability of the deficient mutant also suggests that SUF, the sole Fe-S cluster machinery identified is non-essential in S. mutans, which is not known in any other bacterium lacking the NIF and/or ISC system. However, how the bacterium compensates the Fe-S deficiency and if any novel Fe-S assembly systems exist in this bacterium await further investigation.}, } @article {pmid34248873, year = {2021}, author = {Sahoo, A and Swain, SS and Behera, A and Sahoo, G and Mahapatra, PK and Panda, SK}, title = {Antimicrobial Peptides Derived From Insects Offer a Novel Therapeutic Option to Combat Biofilm: A Review.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {661195}, pmid = {34248873}, issn = {1664-302X}, abstract = {Biofilms form a complex layer with defined structures, that attach on biotic or abiotic surfaces, are tough to eradicate and tend to cause some resistance against most antibiotics. Several studies confirmed that biofilm-producing bacteria exhibit higher resistance compared to the planktonic form of the same species. Antibiotic resistance factors are well understood in planktonic bacteria which is not so in case of biofilm producing forms. This may be due to the lack of available drugs with known resistance mechanisms for biofilms. Existing antibiotics cannot eradicate most biofilms, especially of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). Insects produce complex and diverse set of chemicals for survival and defense. Antimicrobial peptides (AMPs), produced by most insects, generally have a broad spectrum of activity and the potential to bypass the resistance mechanisms of classical antibiotics. Besides, AMPs may well act synergistically with classical antibiotics for a double-pronged attack on infections. Thus, AMPs could be promising alternatives to overcome medically important biofilms, decrease the possibility of acquired resistance and treatment of multidrug-resistant pathogens including ESKAPE. The present review focuses on insect-derived AMPs with special reference to anti-biofilm-based strategies. It covers the AMP composition, pathways and mechanisms of action, the formation of biofilms, impact of biofilms on human diseases, current strategies as well as therapeutic options to combat biofilm with antimicrobial peptides from insects. In addition, the review also illustrates the importance of bioinformatics tools and molecular docking studies to boost the importance of select bioactive peptides those can be developed as drugs, as well as suggestions for further basic and clinical research.}, } @article {pmid34246014, year = {2021}, author = {Alonso, VPP and de Oliveira Morais, J and Kabuki, DY}, title = {Incidence of Bacillus cereus, Bacillus sporothermodurans and Geobacillus stearothermophilus in ultra-high temperature milk and biofilm formation capacity of isolates.}, journal = {International journal of food microbiology}, volume = {354}, number = {}, pages = {109318}, doi = {10.1016/j.ijfoodmicro.2021.109318}, pmid = {34246014}, issn = {1879-3460}, mesh = {Animals ; *Bacillus/genetics/metabolism ; *Bacillus cereus/genetics/metabolism ; Biofilms ; *Food Microbiology ; *Geobacillus stearothermophilus/genetics/metabolism ; *Hot Temperature ; Incidence ; *Milk/microbiology ; }, abstract = {The presence of mesophilic and thermophilic spore-forming bacteria in UHT milk, as well as biofilm formation in dairy plants, are concerning. The current study explored the spore-forming bacilli diversity in 100 samples of UHT milk (skimmed and whole). Through this work, a total of 239 isolates from UHT milk samples were obtained. B. cereus s.s. was isolated from 7 samples, B. sporothermodurans from 19 and, G. stearothermophilus from 25 samples. Genes encoding hemolysin (HBL), and non-hemolytic (NHE) enterotoxins were detected in B. cereus s.s. isolates. All isolates of B. cereus s.s. (12) B. sporothermodurans (38), and G. stearothermophilus (47) were selected to verify the ability of biofilm formation in microtiter plates. The results showed all isolates could form biofilms. The OD595 values of biofilm formation varied between 0.14 and 1.04 for B. cereus, 0.20 to 1.87 for B. sporothermodurans, and 0.49 to 2.77 for G. stearothermophilus. The data highlights that the dairy industry needs to reinforce control in the initial quality of the raw material and in CIP cleaning procedures; avoiding biofilm formation and consequently a persistent microbiota in processing plants, which can shelter pathogenic species such as B. cereus s.s.}, } @article {pmid34245845, year = {2021}, author = {Tian, L and Lu, Z and Lei, L and Yang, N and Chen, Z and Lu, B and Jin, Z and Shen, Y and Guo, S}, title = {Preparation, characterization and primary evaluation of trilayered biliary stent films for anti-cholangiocarcinoma and anti-biofilm formation.}, journal = {International journal of pharmaceutics}, volume = {606}, number = {}, pages = {120869}, doi = {10.1016/j.ijpharm.2021.120869}, pmid = {34245845}, issn = {1873-3476}, mesh = {*Bile Duct Neoplasms/drug therapy ; Bile Ducts, Intrahepatic ; *Cholangiocarcinoma/drug therapy ; *Drug-Eluting Stents ; Escherichia coli ; Humans ; Paclitaxel ; Staphylococcus aureus ; Stents ; }, abstract = {Excessive growth of tumor within biliary wall and formation of biofilm on inner surface of stent can cause restenosis or even obstruction after stent implantation. Therefore, it is important and valuable to develop a new biliary stent for anti-cholangiocarcinoma and anti-biofilm formation. Herein, we designed, prepared and primarily evaluated a new trilayered film for biliary stents consisting of one poly (lactic acid) (PLA) layer loaded with anti-tumor paclitaxel (PTX layer), one middle PLA isolation layer (isolation layer) and one PLA layer loaded with antimicrobial ofloxacin (OFLX layer). It is postulated that the PTX layer releases drug towards biliary wall with tumor, the OFLX layer releases drug towards lumen of bile duct and the isolation layer is used to separate from the PTX layer and the OFLX layer and facilitate drug release in unidirectional way. The prepared trilayered films were characterized in terms of morphology, microstructure, crystallinity and biodegradability. It was found that the films could effectively tune drug release by addition of different amounts of drug or PEG, release PTX and OFLX in opposite directions, effectively inhibit the proliferation of human cholangiocarcinoma RBE cells, the adherence of E. coli and S. aureus and the formation of biofilm in vitro. It is potential that the trilayered films can be used to fabricate a new biliary stent with a dual function of anti-cholangiocarcinoma and anti-biofilm formation.}, } @article {pmid34243039, year = {2021}, author = {Pettygrove, BA and Kratofil, RM and Alhede, M and Jensen, PØ and Newton, M and Qvortrup, K and Pallister, KB and Bjarnsholt, T and Kubes, P and Voyich, JM and Stewart, PS}, title = {Delayed neutrophil recruitment allows nascent Staphylococcus aureus biofilm formation and immune evasion.}, journal = {Biomaterials}, volume = {275}, number = {}, pages = {120775}, pmid = {34243039}, issn = {1878-5905}, support = {R01 AI149491/AI/NIAID NIH HHS/United States ; U54 GM115371/GM/NIGMS NIH HHS/United States ; FDN-143248//CIHR/Canada ; }, mesh = {Animals ; Biofilms ; Immune Evasion ; Mice ; Neutrophil Infiltration ; Neutrophils ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {Biofilms that form on implanted medical devices cause recalcitrant infections. The early events enabling contaminating bacteria to evade immune clearance, before a mature biofilm is established, are poorly understood. Live imaging in vitro demonstrated that Staphylococcus aureus sparsely inoculated on an abiotic surface can go undiscovered by human neutrophils, grow, and form aggregates. Small (~50 μm[2]) aggregates of attached bacteria resisted killing by human neutrophils, resulting in neutrophil lysis and bacterial persistence. In vivo, neutrophil recruitment to a peritoneal implant was spatially heterogenous, with some bacterial aggregates remaining undiscovered by neutrophils after 24 h. Intravital imaging in mouse skin revealed that attached S. aureus aggregates grew and remained undiscovered by neutrophils for up to 3 h. These results suggest a model in which delayed recruitment of neutrophils to an abiotic implant presents a critical window in which bacteria establish a nascent biofilm and acquire tolerance to neutrophil killing.}, } @article {pmid34242490, year = {2021}, author = {Salama, OE and Gerstein, AC}, title = {High-Throughput Computational Analysis of Biofilm Formation from Time-Lapse Microscopy.}, journal = {Current protocols}, volume = {1}, number = {7}, pages = {e194}, doi = {10.1002/cpz1.194}, pmid = {34242490}, issn = {2691-1299}, support = {//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Biofilms ; *Candida albicans ; Image Processing, Computer-Assisted ; *Microscopy ; Time-Lapse Imaging ; }, abstract = {Candida albicans biofilm formation in the presence of drugs can be examined through time-lapse microscopy. In many cases, the images are used qualitatively, which limits their utility for hypothesis testing. We employed a machine-learning algorithm implemented in the Orbit Image Analysis program to detect the percent area covered by cells from each image. This is combined with custom R scripts to determine the growth rate, growth asymptote, and time to reach the asymptote as quantitative proxies for biofilm formation. We describe step-by-step protocols that go from sample preparation for time-lapse microscopy through image analysis parameterization and visualization of the model fit. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Sample preparation Basic Protocol 2: Time-lapse microscopy: Evos protocol Basic Protocol 3: Batch file renaming Basic Protocol 4: Machine learning analysis of Evos images with Orbit Basic Protocol 5: Parametrization of Orbit output in R Basic Protocol 6: Visualization of logistic fits in R.}, } @article {pmid35019629, year = {2020}, author = {Le, PH and Nguyen, DHK and Aburto-Medina, A and Linklater, DP and Crawford, RJ and MacLaughlin, S and Ivanova, EP}, title = {Nanoscale Surface Roughness Influences Candida albicans Biofilm Formation.}, journal = {ACS applied bio materials}, volume = {3}, number = {12}, pages = {8581-8591}, doi = {10.1021/acsabm.0c00985}, pmid = {35019629}, issn = {2576-6422}, abstract = {The microbial contamination of surfaces presents a significant challenge due to the adverse effects associated with biofilm formation, particularly on implantable devices. Here, the attachment and biofilm formation of the opportunistic human pathogen, Candida albicans ATCC 10231, were studied on surfaces with decreasing magnitudes of nanoscale roughness. The nanoscale surface roughness of nonpolished titanium, polished titanium, and glass was characterized according to average surface roughness, skewness, and kurtosis. Nonpolished titanium, polished titanium, and glass possessed average surface roughness (Sa) values of 350, 20, and 2.5 nm; skewness (Sskw) values of 1.0, 4.0, and 1.0; and (Skur) values of 3.5, 16, and 4, respectively. These unique characteristics of the surface nanoarchitecture were found to play a key role in limiting C. albicans attachment and modulating the functional phenotypic changes associated with biofilm formation. Our results suggest that surfaces with a specific combination of surface topographical parameters could prevent the attachment and biofilm formation of C. albicans. After 7 days, the density of attached C. albicans cells was recorded to be 230, 70, and 220 cells mm[-2] on nonpolished titanium, polished titanium, and glass surfaces, respectively. Despite achieving a very low attachment density, C. albicanscells were only observed to produce hyphae associated with biofilm formation on nonpolished titanium surfaces, possessing the highest degree of surface roughness (Sa = 350 nm). This study provides a more comprehensive picture of the impact of surface architectures on C. albicans attachment, which is beneficial for the design of antifungal surfaces.}, } @article {pmid35019610, year = {2020}, author = {Zhu, J and Wang, M and Zhang, H and Yang, S and Song, KY and Yin, R and Zhang, W}, title = {Effects of Hydrophilicity, Adhesion Work, and Fluid Flow on Biofilm Formation of PDMS in Microfluidic Systems.}, journal = {ACS applied bio materials}, volume = {3}, number = {12}, pages = {8386-8394}, doi = {10.1021/acsabm.0c00660}, pmid = {35019610}, issn = {2576-6422}, abstract = {Polydimethylsiloxane (PDMS) has been the most widely used material in microfluidic systems, especially for cell biology applications. However, the antibacterial performance of PDMS in flow conditions has never been reported in the literature. In this paper, we analyzed the effects of contact angle (CA), adhesion force (work), and surface free energy on the antibacterial activities of PDMS by varying the ratio of curing agents (crosslinking degree) and surface modification with oxygen plasma. The results show that the Young's modulus has no particular effects on bacterial adhesion compared to the CAs of samples. For the first time, we analyzed the adhesion work (AW) effect on biofilm formation, and we found that biofilms tend to form on the surface with less AW. Furthermore, we analyzed the dual effect of hydrophilicity and shear force induced by fluid flow on the bacterial adhesion in PDMS microfluidic systems. We found that at low flow rates in microfluidic conditions, the adhesion of the bacteria on the PDMS surface is inhibited when the fluid flow exceeds a certain value. It required higher shear force to inhibit bacterial adhesion on the hydrophilic surface than on the hydrophobic surface. Therefore, hydrophilicity might be the dominant factor affecting bacterial adhesion.}, } @article {pmid35021800, year = {2020}, author = {Yan, Y and Soraru, C and Keller, V and Keller, N and Ploux, L}, title = {Antibacterial and Biofilm-Preventive Photocatalytic Activity and Mechanisms on P/F-Modified TiO2 Coatings.}, journal = {ACS applied bio materials}, volume = {3}, number = {9}, pages = {5687-5698}, doi = {10.1021/acsabm.0c00467}, pmid = {35021800}, issn = {2576-6422}, abstract = {Photocatalytic antibacterial and biofilm-preventive activity in liquid of heavy-metal-free coatings based on a phosphorus (P)- and fluorine (F)-modified TiO2 photocatalyst has been investigated. They reveal significantly higher immediate and longer-term (biofilm-preventive) inactivation capacity than a reference coating made of the commercial photocatalyst TiO2 P25 on three bacterial species differing in cell wall type and ability to resist oxidative stress (Escherichia coli, Staphylococcus epidermidis, Pseudomonas fluorescens) (up to more than 99% reduction of colonization on P/F-modified TiO2 coating compared to about 50% on P25 TiO2 coating for 10 min UV-A illumination). This results from the P- and F-induced improvement of photocatalyst properties and from the smoother surface topography, which shortens reactive oxygen species (ROS) diffusion to the outer membrane of the targeted adhered bacteria. Decrease in ROS-related impairment of cell wall, respiratory, and enzymatic activities confirms the loss of ROS throughout the bacterial cell degradation. Staphylococcus epidermidis and Pseudomonas fluorescens are less sensitive than Escherichia coli, with a probable relation to the bacterial oxygen stress defense mechanism. The coating antibacterial efficacy was highly affected by phosphate ions and the richness in dissolved oxygen of the reaction medium.}, } @article {pmid35021764, year = {2020}, author = {Chen, M and Zhang, S and He, Z}, title = {Controlled Block Polypeptide Composed of d-Type Amino Acids: A Therapeutics Delivery Platform to Inhibit Biofilm Formation of Drug-Resistant Bacteria.}, journal = {ACS applied bio materials}, volume = {3}, number = {9}, pages = {6343-6350}, doi = {10.1021/acsabm.0c00795}, pmid = {35021764}, issn = {2576-6422}, abstract = {Antibiotic resistance of bacteria has been widely developed due to biofilm protection and separating the bacteria from antibiotics. The phenomenon of biofilm inhibition or disassembly by d-amino acids (DAAs) has been reported recently, while it was also challenged by some other scientists. Presuming DAAs work for biofilms on the surface of bacteria, delivery of the DAAs to disease sites is important while small DAAs are easily removed by kidney. To resolve the above issues, it is urgent to develop a biofilm inhibitor. To achieve this goal, we synthesized d-type polypeptides via NCA ring-opening polymerization with the initiator of HMDS to generate poly(CBZ-l-lysine)33-block-poly(d-phenylalanine)14. After deprotection, the resultant polypeptides were converted into amphiphilic poly(l-lysine)33-block-poly(d-phenylalanine)14, which can be self-assembled into well-defined homogeneous nanoparticles capable of capsulizing penicillin G. For the molecular weight of polypeptides resulting in various bioeffects, we prepared similar-sized polypeptides of an l-type equivalent polypeptide as control. The data from microbial experiments indicated that poly(l-lysine)33-block-poly(d-phenylalanine)14 can inhibit biofilm formation of Bacillus subtilis at a low final concentration (24 μg/mL), much stronger than poly(l-lysine)40-block-poly(l-phenylalanine)19 at the same concentration. This is the first report in that synthetic d-type polypeptides can inhibit biofilms of bacteria. Poly(l-lysine)33-block-poly(d-phenylalanine)14 can be assembled into well-defined, biostable homogeneous nanoparticles. This research provides a potential solution to overcome bacteria antibiotic resistance from small molecules to material sciences and gives a unique angle to understand the current dispute if DAAs can disassemble the biofilms. Additionally, these nanoparticles have great potential in the development of nanomedicines with a longer circulation time in blood and this discovery has implications in developing antimicrobial nanodevices for therapy and basic scientific interest.}, } @article {pmid35025378, year = {2020}, author = {García-Bonillo, C and Texidó, R and Reyes-Carmenaty, G and Gilabert-Porres, J and Borrós, S}, title = {Study of the Human Albumin Role in the Formation of a Bacterial Biofilm on Urinary Devices Using QCM-D.}, journal = {ACS applied bio materials}, volume = {3}, number = {5}, pages = {3354-3364}, doi = {10.1021/acsabm.0c00286}, pmid = {35025378}, issn = {2576-6422}, abstract = {Catheter-associated urinary tract infections (CAUTIs) are the most common health care-associated infections due to rapid bacterial colonization+ and biofilm formation in urinary catheters. This behavior has been extensively documented in medical devices. However, there is a few literature works on CAUTI providing a model that allows the exhaustive study of biofilm formation in a urinary environment. The development of an effective model would be helpful to identify the factors that promote the biofilm formation and identify strategies to avoid it. In this work, we have developed a model to test biofilm formation on urinary medical device surfaces by simulating environmental and physical conditions using a quartz crystal microbalance with dissipation (QCM-D) module with an uropathogenic strain. Moreover, we used the developed model to study the role of human albumin present in artificial urine at high concentrations because of renal failure or heart-diseases in patients. Despite model limitations using artificial urine, these tests show that human albumin can be considered as a promoter of biofilm formation on hydrophobic surfaces, being a possible risk factor to developing a CAUTI.}, } @article {pmid35019312, year = {2020}, author = {Li, P and Liu, S and Zhang, G and Yang, X and Cao, W and Gong, X and Xing, X}, title = {Design of pH-Responsive Dissociable Nanosystem Based on Carbon Dots with Enhanced Anti-biofilm Property and Excellent Biocompatibility.}, journal = {ACS applied bio materials}, volume = {3}, number = {2}, pages = {1105-1115}, doi = {10.1021/acsabm.9b01053}, pmid = {35019312}, issn = {2576-6422}, abstract = {Bacterial biofilm poses a serious threat to human health, leading to increased and prolonged bacterial infections. How to solve the problem of eliminating biofilms effectively and rapidly while being nontoxic to normal cells is still a challenge. Here, we design a pH-sensitive anti-biofilm nanosystem formed by self-assembly between negatively charged carboxyl groups of poly(ethylene glycol_-COOH-polyethylenimine-2,3-dimethylmaleic anhydride (PPD) and positively charged amines on the surface of carbon dots derived from the ashes of calcined l-lysine powder (CDLys) (PPD@CDLys for short). The outmost copolymer could make PPD@CDLys facilely diffuse into the dense biofilm and reverse to be positively charged via hydrolysis, which lead to the acid-triggered disassembly of the nanosystem. After hydrolyzation, PPD would turn into a biocidal cationic polymer, which is prone to attaching on bacteria inside the biofilm and efficiently killing them. In addition, the released CDLys could induce intracellular reactive oxygen species (ROS) across the whole biofilm to degrade the matrix of extracellular polymer substances and kill resident bacteria deep into the biofilm. Finally, the prepared nanosystem effectively inhibits the formation of Staphylococcus aureus biofilm and rapidly destroys the mature biofilm by the synergy antibacterial effects of the cation and ROS. We also evaluate the biocompatibility of the nanocomposites. The results show that PPD@CQDLys has no toxicity to L929 and 3T3 cells and exhibits a zero hemolytic rate even when the concentration is up to 2000 μg/mL. The outstanding biocompatibility coupled with rapid anti-biofilm ability of the nanosystem presents an opportunity for it to be utilized as an effective pH-responsive and targetable anti-biofilm agent for controlling bacterial infections.}, } @article {pmid35019455, year = {2020}, author = {Deepika, MS and Thangam, R and Sundarraj, S and Sheena, TS and Sivasubramanian, S and Kulandaivel, J and Thirumurugan, R}, title = {Co-delivery of Diverse Therapeutic Compounds Using PEG-PLGA Nanoparticle Cargo against Drug-Resistant Bacteria: An Improved Anti-biofilm Strategy.}, journal = {ACS applied bio materials}, volume = {3}, number = {1}, pages = {385-399}, doi = {10.1021/acsabm.9b00850}, pmid = {35019455}, issn = {2576-6422}, abstract = {Controlling biofilms of bacteria is a challenging aspect because of their drug-resistance potentials against a range of antibiotics, demanding the development of active anti-biofilm agents. Rutin (R), a natural antioxidant, and benzamide (B), a synthetic antibacterial agent, have several pharmacological and antibacterial abilities. Herein, we developed PEG-PLGA NPs that synergistically carried rutin and benzamide as drug candidates, while displaying therapeutic and anti-biofilm functions. These drug delivery NPs were synthesized by the oil-in-water emulsion (O/W) solvent evaporation technique. The obtained NPs were characterized by UV-vis, FT-IR, SEM, TEM, and DLS measurements. Confocal laser scanning microscopy was employed to evaluate the anti-biofilm capabilities against Staphylococcus aureus and Pseudomonas aeruginosa and further quantified the levels of residual biofilm constituents such as protein and exopolysaccharide (EPS). Drug release experiments showed the controlled release of rutin-benzamide (RB) for several days. Antibacterial analyses showed that the minimum inhibitory concentration (MIC) of NPs was at least two times lower than that of the free drugs. RB-PEG-PLGA NPs revealed that they targeted biofilm-forming bacteria through the disruption of the membrane and biofilm surface and were observed to be nontoxic when tested using human erythrocytes and human cell lines. In vivo evaluations in zebrafish showed that the NPs did not alter the antioxidant functions and histological features of tissues. On the basis of results obtained, it is substantiated that the rutin-benzamide-loaded nanocarrier offers potential anti-biofilm therapy due to its high anti-biofilm activity and biocompatibility.}, } @article {pmid35019444, year = {2020}, author = {Zhang, S and Liang, X and Gadd, GM and Zhao, Q}, title = {Superhydrophobic Coatings for Urinary Catheters To Delay Bacterial Biofilm Formation and Catheter-Associated Urinary Tract Infection.}, journal = {ACS applied bio materials}, volume = {3}, number = {1}, pages = {282-291}, doi = {10.1021/acsabm.9b00814}, pmid = {35019444}, issn = {2576-6422}, abstract = {In this research, a multilayered superhydrophobic coating for urinary catheters was synthesized by a layer-by-layer deposition technique. A mussel-inspired polydopamine coating was utilized as a platform for the in situ anchoring of silver nanoparticles followed by hydrophobic modification with 1H,1H,2H,2H-perfluorodecanethiol. Benefiting from the synergistic effect of hierarchical micro/nanostructures and antibacterial silver nanoparticles, the prepared catheters exhibited excellent superhydrophobicity and prolonged antibacterial activity against Escherichia coli WT F1693 and Proteus mirabilis WT F1697. Compared with commercial all-silicone and silver-alloy-hydrogel catheters, the superhydrophobic catheter exhibited significant antibiofilm activities in both static and dynamic models. In an in vitro bladder model, bacterial migration along the outer catheter was effectively delayed, reducing biomass accumulation by up to 55 and 90% compared with all-silicone and silver-alloy-hydrogel catheters. Encrustations in the catheter lumen were also retarded, extending the lifetime of silicone catheters from ∼40 to ∼100 h. The superhydrophobic catheter also exhibited good biocompatibility to the L929 mouse fibroblasts, therefore providing a promising direction for the future design of urinary catheters.}, } @article {pmid35021493, year = {2019}, author = {Ostrov, I and Polishchuk, I and Shemesh, M and Pokroy, B}, title = {Superhydrophobic Wax Coatings for Prevention of Biofilm Establishment in Dairy Food.}, journal = {ACS applied bio materials}, volume = {2}, number = {11}, pages = {4932-4940}, doi = {10.1021/acsabm.9b00674}, pmid = {35021493}, issn = {2576-6422}, abstract = {Microbial contamination of dairy products caused by biofilm-forming bacteria is of great concern to the dairy industry, a leading sector impacted by food loss. Previous reports have emphasized that preventing biofilm formation on work surfaces of dairy equipment would be a more desirable option than treating it. However, there is currently no available technology that could completely prevent such biofilm formation without causing detrimental side effects. Here, we demonstrate that a bioinspired approach, exploiting superhydrophobic paraffin/fluorinated wax surfaces, can be efficiently employed to prevent dairy-associated biofilm formation. Our results showed that under conditions relevant to dairy food production (continuous flow of milk in the presence of substrates relevant to the dairy industry), biofilm development by strong biofilm-forming dairy Bacillus isolates was effectively mitigated (up to 97-99% inhibition) on the tested wax surfaces. This, coupled with the ability of these wax surfaces to retain their structure and functionality after prolonged exposure to milk, without producing any negative effects on milk quality, makes the technology potentially applicable in the dairy industry.}, } @article {pmid35026895, year = {2019}, author = {Dai, X and Yu, Y and Wei, X and Dai, X and Duan, X and Yu, C and Zhang, X and Li, C}, title = {Peptide-Conjugated CuS Nanocomposites for NIR-Triggered Ablation of Pseudomonas aeruginosa Biofilm.}, journal = {ACS applied bio materials}, volume = {2}, number = {4}, pages = {1614-1622}, doi = {10.1021/acsabm.9b00033}, pmid = {35026895}, issn = {2576-6422}, abstract = {The Gram-negative bacteria Pseudomonas aeruginosa is one famous bacterial strain owing to its ability to effectively form biofilms, which is a front-line mechanism of bacterial tolerance. Herein, the near-infrared-induced nanocomposites were one-step prepared by modifying copper sulfide nanoparticle with peptide to effectively eradicate Pseudomonas aeruginosa biofilm through electrostatic interaction, photodynamic effect and photothermal effect. These nanocomposites could rapidly adhere to the surface of bacteria, and irreversible damage the bacterial membrane under near-infrared laser irradiation. Furthermore, the nanocomposites could selectively eliminate bacteria over mammalian cell without distinct toxicity to NIH 3T3 cells. The nanocomposites will exert a far-reaching impact on the future design of biocompatible near-infrared-induced antibacterial agents, exhibiting its potential applications in Gram-negative bacteria and biofilm infections.}, } @article {pmid34541137, year = {2017}, author = {Sendersky, E and Simkovsky, R and Golden, SS and Schwarz, R}, title = {Quantification of Chlorophyll as a Proxy for Biofilm Formation in the Cyanobacterium Synechococcus elongatus.}, journal = {Bio-protocol}, volume = {7}, number = {14}, pages = {e2406}, pmid = {34541137}, issn = {2331-8325}, abstract = {A self-suppression mechanism of biofilm development in the cyanobacterium Synechococcus elongatus PCC 7942 was recently reported. These studies required quantification of biofilms formed by mutants impaired in the biofilm-inhibitory process. Here we describe in detail the use of chlorophyll measurements as a proxy for biomass accumulation in sessile and planktonic cells of biofilm-forming strains. These measurements allow quantification of the total biomass as estimated by chlorophyll level and representation of the extent of biofilm formation by depicting the relative fraction of chlorophyll in planktonic cells.}, } @article {pmid34242193, year = {2021}, author = {Abdelraheem, WM and Mohamed, ES}, title = {The effect of Zinc Oxide nanoparticles on Pseudomonas aeruginosa biofilm formation and virulence genes expression.}, journal = {Journal of infection in developing countries}, volume = {15}, number = {6}, pages = {826-832}, doi = {10.3855/jidc.13958}, pmid = {34242193}, issn = {1972-2680}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Gene Expression Regulation, Bacterial ; Humans ; Microbial Sensitivity Tests ; Nanoparticles ; Pseudomonas aeruginosa/*drug effects/genetics ; Virulence Factors/genetics ; Zinc Oxide/chemistry/*pharmacology ; }, abstract = {INTRODUCTION: Due to increased resistance to antimicrobial agents, infectious diseases remain a public health problem worldwide. The current study was designed to examine the effect of Zinc Oxide nanoparticles (ZnO-np) against the biofilm formation ability of P. aeruginosa clinical isolates and to study its effect on the expression level of the genes involved in biofilm formation and virulence factors production.

METHODOLOGY: The MIC of ZnO-np against P. aeruginosa was determined by the broth micro dilution method. The effect of ZnO-np on the biofilm-forming isolates of P. aeruginosa was monitored by the microtiter plate method. P. aeruginosa isolates were tested for the expression of different biofilm and virulence genes using real-time rt-PCR.

RESULTS: ZnO-np significantly down-regulated the expression level of all biofilm and virulence genes of P. aeruginosa clinical isolates except the toxA gene.

CONCLUSIONS: This study demonstrates the promising use of ZnO-np as an anti-biofilm and anti-virulence compound.}, } @article {pmid34239764, year = {2021}, author = {Ozdemir, S and Aydogan, O and Koksal Cakirlar, F}, title = {Biofilm Formation and Antimicrobial Susceptibility of Non-Diphtheria Corynebacterium Strains Isolated from Blood Cultures: First Report from Turkey.}, journal = {Medeniyet medical journal}, volume = {36}, number = {2}, pages = {123-129}, pmid = {34239764}, issn = {2149-2042}, abstract = {OBJECTIVE: Non-diphtheriae Corynebacterium strains have been recognized as important pathogens after decades of confusion regarding their microbiological classification and clinical significance. The aim of this study was to identify non-diphtheriae Corynebacterium strains and the prevalence of biofilm formation and antimicrobial resistance.

METHOD: In total, 126 non-diphtheriae Corynebacterium strains were isolated from blood cultures of inpatients with bacteremia in our hospital between January 2015 and January 2020. Blood cultures were analyzed with the Bactec-9120 system. Strains were identified using MALDI-TOF MS (Bruker Daltonics, Germany). Antimicrobial susceptibilities were determined using the Kirby-Bauer disk diffusion method on a Mueller-Hinton agar and evaluated according to EUCAST standards. Biofilm formation was assessed with the Congo Red Agar method.

RESULTS: Corynebacterium striatum and Corynebacterium matruchotii were the most prevalent with 29 and 26 isolates, respectively. Biofilm production was detected in 62.06% (18/29) of C. striatum, in 53.8% (14/26) of C. matruchotii, in 50% (9/18) of Corynebacterium afermentans, 50% (6/12) of Corynebacterium amycolatum, and in 46% (7/15) of Corynebacterium jeikeium strains. Among the five most prevalent strains, we found a high biofilm rate of 54%. The resistance rates to penicillin, clindamycin, ciprofloxacin, rifampicin, tetracycline, and gentamicin were 91.2%, 87.3%, 79.3%, 56.3%, 45.2%, and 39.6%, respectively. All 126 strains were susceptible to vancomycin and linezolid.

CONCLUSION: Non-diphtheriae Corynebacterium strains isolated from blood cultures of hospitalized patients with bacteremia may have multidrug resistance and the ability to produce biofilm. These results emphasize the importance of identifying strains and determining their antimicrobial susceptibility and biofilm production potential.}, } @article {pmid34238148, year = {2022}, author = {Nasser, A and Dallal, MMS and Jahanbakhshi, S and Azimi, T and Nikouei, L}, title = {Staphylococcus aureus: Biofilm Formation and Strategies Against it.}, journal = {Current pharmaceutical biotechnology}, volume = {23}, number = {5}, pages = {664-678}, doi = {10.2174/1389201022666210708171123}, pmid = {34238148}, issn = {1873-4316}, mesh = {Biofilms ; Humans ; Quorum Sensing ; *Staphylococcal Infections ; *Staphylococcus aureus ; Virulence Factors ; }, abstract = {Formation of Staphylococcus aureus biofilm causes significant infections in the human body. Biofilm forms through the aggregation of bacterial species and brings about many complications. It mediates drug resistance and persistence and facilitates the recurrence of infection at the end of antimicrobial therapy. Biofilm formation is completed in a series of steps, and any interference in these steps can disrupt its formation. Such interference may occur at any stage of biofilm production, including attachment, monolayer formation, and accumulation. Interfering agents can act as quorum sensing inhibitors and interfere in the functionality of quorum sensing receptors, attachment inhibitors, and affect cell hydrophobicity. Among these inhibiting strategies, attachment inhibitors could serve as the best agents against biofilm formation, because in case pathogens abort the attachment, the next stages of biofilm formation, e.g., accumulation and dispersion, will fail to materialize. Inhibition at this stage leads to suppression of virulence factors and invasion. One of the best knowing inhibitors is a chelator that collects metal, Fe+, Zn+, and magnesium critical for biofilm formation. These effective factors in the binding and formation of biofilm are investigated, and the coping strategy is discussed. This review examines the stages of biofilm formation and determines what factors interfere in the continuity of these steps. Finally, the inhibition strategies are investigated, reviewed, and discussed.}, } @article {pmid34237581, year = {2021}, author = {Cai, S and Meng, K and Liu, P and Cao, X and Wang, G}, title = {Suppressive effects of gecko cathelicidin on biofilm formation and cariogenic virulence factors of Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {129}, number = {}, pages = {105205}, doi = {10.1016/j.archoralbio.2021.105205}, pmid = {34237581}, issn = {1879-1506}, mesh = {Animals ; Antimicrobial Cationic Peptides ; Biofilms ; *Dental Caries/prevention & control ; Humans ; *Lizards ; Streptococcus mutans ; Virulence Factors ; Cathelicidins ; }, abstract = {OBJECTIVE: The aims of this study were to investigate the effectivity of gecko cathelicidin Gj-CATH2 on biofilm formation and cariogenic virulence factors of S. mutans, and preliminary explore its function mechanisms.

DESIGN: Minimum inhibitory concentration and bacterial killing kinetics assays were performed to assess the antimicrobial effect of Gj-CATH2.The influence of Gj-CATH2 on S. mutans biofilm formation was determined by crystal violet staining method and observed by SEM. The effects of Gj-CATH2 on exopolysaccharides (EPS) synthesis, bacterial aggregation, acidogenicity and aciduricity of S. mutans were also investigated. Quantitative real-time PCR was conducted to acquire the expression profile of related genes.

RESULTS: Gj-CATH2 showed strong bactericidal and anti-biofilm effects on S. mutans. SEM confirmed the reduction of the dense structure in S. mutans biofilm in Gj-CATH2-treated groups. Gj-CATH2 significantly inhibited EPS synthesis, cell aggregation, acid production of S. mutans, but showed no influence on its acid proof. Furthermore, the expression of genes related to biofilm formation (gtfB/C/D, gbpB/D), quorum sensing system (luxS and comD/E) and acidogenicity (ldh) was significantly suppressed by Gj-CATH2. Gj-CATH2 also displayed advantageous resistance in human saliva and exhibited negligible toxicity against mammalian cells.

CONCLUSIONS: Gj-CATH2 inhibited S. mutans biofilm formation by targeting the bacterial adhesion and the biofilm maturation stages. Gj-CATH2 significantly suppressed virulence factors production of S. mutans, resulting in decreased EPS synthesis and reduced acidogenicity of bacteria. These findings suggest Gj-CATH2 might be a promising agent for clinical application in prevention of dental caries.}, } @article {pmid34237534, year = {2021}, author = {Cai, W and Wang, B and Liu, W and Yao, H and Deng, Y and Wang, A}, title = {Sessile methanogens dominated cathodic biofilm: Distribution and network in physiological transitions.}, journal = {The Science of the total environment}, volume = {795}, number = {}, pages = {148724}, doi = {10.1016/j.scitotenv.2021.148724}, pmid = {34237534}, issn = {1879-1026}, mesh = {*Biofilms ; Electrodes ; Electron Transport ; }, abstract = {A mature cathodic biofilm plays the key role in biocathode electron transfer. The physiological transitions of it were of great interests as the sessile and dispersed (planktonic) work in a balance while it is still lack of understanding. In this study, an improved sampling method was used for detecting sessile, detached, and dispersed microorganisms. The results indicated a certain number of methanogens (82.6%) and its associated phyla (60%-90%) are immobilized as sessile biofilm. The Tax4Fun predicted a lower abundance of mobility associated genes and a significant enrichment (t-test, P = 0.003) of c-di-GMP in sessile biofilm. Overall, the microbial interaction and motility were predicted as two factors to affect the physiological transitions of cathodic biofilm. This finding could shed a light on the investigation of cathodic biofilm in a dynamic transition rather than a static community, playing a pivotal role in understanding the relation between specific property of biofilm.}, } @article {pmid34237525, year = {2021}, author = {Zhao, X and Kuipers, OP}, title = {Synthesis of silver-nisin nanoparticles with low cytotoxicity as antimicrobials against biofilm-forming pathogens.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {206}, number = {}, pages = {111965}, doi = {10.1016/j.colsurfb.2021.111965}, pmid = {34237525}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Escherichia coli ; Humans ; *Nanoparticles ; *Nisin ; Staphylococcus aureus ; }, abstract = {Wound infection is a serious threat to patients, in particular those with septic wound infections, which result in high mortality rates. Moreover, the treatment of wound infections with antimicrobial-resistant and/or biofilm-forming pathogens can be challenging. Nisin, a potent antimicrobial against Gram-positive bacterial pathogens, has been used in the food industry as a preservative for decades. Silver has been approved by the FDA as a topical antimicrobial. Here, we show that silver-nisin nanoparticles (Ag-nisin NP), with an average diameter of 60 nm, can be quickly synthesized with the assistance of a simple microwave. Ag-nisin NP act as bactericidal antibiotics against the tested pathogens. In contrast, resistance was observed in S. aureus and A. baumannii that were treated with silver nitrate alone. In addition, Ag-nisin NP showed potent antibiofilm activity against S. aureus, P. aeruginosa, A. baumannii, K. pneumoniae, and E. coli, which are pathogens occurring in wound infections. Notably, the synthesized Ag-nisin NP showed lower cytotoxicity than silver nitrate to human cells. This formulation provides an alternative and safe measurement for biofilm-infected wound control.}, } @article {pmid34235733, year = {2022}, author = {Veiga, FF and de Castro-Hoshino, LV and Sato, F and Baesso, ML and Silva, S and Negri, M and Svidzinski, TIE}, title = {Characterization of a biofilm formed by Fusarium oxysporum on the human nails.}, journal = {International journal of dermatology}, volume = {61}, number = {2}, pages = {191-198}, doi = {10.1111/ijd.15747}, pmid = {34235733}, issn = {1365-4632}, support = {//Fundação Araucária/ ; //Financiadora de Estudos e Projetos/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Biofilms ; *Fusarium ; Humans ; Nails ; *Onychomycosis ; }, abstract = {BACKGROUND: Fusarium spp. has been considered as an onychomycosis agent, but little is known about the etiopathogenesis of fusarial onychomycosis; thus, the objective of this study was to characterize the fungal-nail interaction and the consequences of the nail infection process by Fusarium oxysporum using the human nail, in an ex vivo model.

METHODS: The kinetic of biofilm production and infection by F. oxysporum using the nail as the only nutritional source were evaluated by scanning electron microscopy, number of culturable cells, metabolic activity, characterization of extracellular matrix, spectroscopy and histopathology analyses.

RESULTS: After evaluating the biofilm kinetic over 7 days using different parameters and techniques, it was possible to characterize the Fusarium-nail interaction.

CONCLUSIONS: This study is a part of a big project aiming to clarify the fusarial pathogenesis and contributes to proving F. oxysporum is able to adapt, grow, develop, and form a biofilm on healthy human nails, which are crucial steps for the invasion process.}, } @article {pmid34235691, year = {2021}, author = {Kachieng'a, LO and Unuofin, JO}, title = {The potentials of biofilm reactor as recourse for the recuperation of rare earth metals/elements from wastewater: a review.}, journal = {Environmental science and pollution research international}, volume = {28}, number = {33}, pages = {44755-44767}, pmid = {34235691}, issn = {1614-7499}, mesh = {Bacteria ; Biofilms ; Metals ; *Metals, Rare Earth ; *Wastewater ; }, abstract = {Wastewater is nowadays increasingly receiving global attention as a resource much more than a problem due to its potential so serve as a resource recovery channel. In this regard, wastewater is gradually been transformed from being a cesspool to a "treasure pool." Among notable resources in the treasure pool, rare earth metals/elements (REEs) warrant focal investigation, both in terms of environmental abundance and biorecovery, due to their environmental impacts. The ineffectiveness or cost intensiveness of extant physicochemical and advanced wastewater resource recovery techniques warrants the investigation of natural phenomenons in the treasure pools. Bacteria are able to cleverly secrete certain biochemicals to help trap and aggregate nutrients for their metabolism-the biofilms. In this regard, there is increased espousal of biofilm-enabled reactors, especially for the application of the recovery of invaluable feedstock in wastewater as well as other aqueous media due to high production rates and stability of cells. Furthermore, it anticipated that this technology will be translated to recovery of rare earth elements, due to their increased demand across the globe. This piece reiterates the nitty-gritty of biofilm-enhanced biorecovery and also keeps the scientific readership abreast of the multifarious aspects regarding the successful biofilm affected biorecovery of REEs at reactor scale.}, } @article {pmid34234829, year = {2021}, author = {Ghasemi, N and Behnezhad, M and Asgharzadeh, M and Zeinalzadeh, E and Kafil, HS}, title = {Corrigendum to "Antibacterial Properties of Aloe vera on Intracanal Medicaments against Enterococcus faecalis Biofilm at Different Stages of Development".}, journal = {International journal of dentistry}, volume = {2021}, number = {}, pages = {9825216}, pmid = {34234829}, issn = {1687-8728}, abstract = {[This corrects the article DOI: 10.1155/2020/8855277.].}, } @article {pmid34234747, year = {2021}, author = {Pacheco, T and Gomes, AÉI and Siqueira, NMG and Assoni, L and Darrieux, M and Venter, H and Ferraz, LFC}, title = {SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {597735}, pmid = {34234747}, issn = {1664-302X}, abstract = {Klebsiella pneumoniae is a Gram-negative pathogen that has become a worldwide concern due to the emergence of multidrug-resistant isolates responsible for various invasive infectious diseases. Biofilm formation constitutes a major virulence factor for K. pneumoniae and relies on the expression of fimbrial adhesins and aggregation of bacterial cells on biotic or abiotic surfaces in a coordinated manner. During biofilm aggregation, bacterial cells communicate with each other through inter- or intra-species interactions mediated by signallng molecules, called autoinducers, in a mechanism known as quorum sensing (QS). In most Gram-negative bacteria, intra-species communication typically involves the LuxI/LuxR system: LuxI synthase produces N-acyl homoserine lactones (AHLs) as autoinducers and the LuxR transcription factor is their cognate receptor. However, K. pneumoniae does not produce AHL but encodes SdiA, an orphan LuxR-type receptor that responds to exogenous AHL molecules produced by other bacterial species. While SdiA regulates several cellular processes and the expression of virulence factors in many pathogens, the role of this regulator in K. pneumoniae remains unknown. In this study, we describe the characterization of sdiA mutant strain of K. pneumoniae. The sdiA mutant strain has increased biofilm formation, which correlates with the increased expression of type 1 fimbriae, thus revealing a repressive role of SdiA in fimbriae expression and bacterial cell adherence and aggregation. On the other hand, SdiA acts as a transcriptional activator of cell division machinery assembly in the septum, since cells lacking SdiA regulator exhibited a filamentary shape rather than the typical rod shape. We also show that K. pneumoniae cells lacking SdiA regulator present constant production of QS autoinducers at maximum levels, suggesting a putative role for SdiA in the regulation of AI-2 production. Taken together, our results demonstrate that SdiA regulates cell division and the expression of virulence factors such as fimbriae expression, biofilm formation, and production of QS autoinducers in K. pneumoniae.}, } @article {pmid34234158, year = {2021}, author = {Pipattanachat, S and Qin, J and Rokaya, D and Thanyasrisung, P and Srimaneepong, V}, title = {Biofilm inhibition and bactericidal activity of NiTi alloy coated with graphene oxide/silver nanoparticles via electrophoretic deposition.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {14008}, pmid = {34234158}, issn = {2045-2322}, abstract = {Biofilm formation on medical devices can induce complications. Graphene oxide/silver nanoparticles (GO/AgNPs) coated nickel-titanium (NiTi) alloy has been successfully produced. Therefore, the aim of this study was to determine the anti-bacterial and anti-biofilm effects of a GO/AgNPs coated NiTi alloy prepared by Electrophoretic deposition (EPD). GO/AgNPs were coated on NiTi alloy using various coating times. The surface characteristics of the coated NiTi alloy substrates were investigated and its anti-biofilm and anti-bacterial effect on Streptococcus mutans biofilm were determined by measuring the biofilm mass and the number of viable cells using a crystal violet assay and colony counting assay, respectively. The results showed that although the surface roughness increased in a coating time-dependent manner, there was no positive correlation between the surface roughness and the total biofilm mass. However, increased GO/AgNPs deposition produced by the increased coating time significantly reduced the number of viable bacteria in the biofilm (p < 0.05). Therefore, the GO/AgNPs on NiTi alloy have an antibacterial effect on the S. mutans biofilm. However, the increased surface roughness does not influence total biofilm mass formation (p = 0.993). Modifying the NiTi alloy surface using GO/AgNPs can be a promising coating to reduce the consequences of biofilm formation.}, } @article {pmid34232751, year = {2021}, author = {ElGindi, M and Al-Baghdadi, R and Jackman, AB and Antonyan, AS and McMahon, DL and Taj-Aldeen, SJ and Finkel, JS}, title = {Where the infection is isolated rather than the specific species correlates with adherence strength, whereas biofilm density remains static in clinically isolated Candida and arthroconidial yeasts.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {7}, pages = {497-505}, doi = {10.1139/cjm-2020-0215}, pmid = {34232751}, issn = {1480-3275}, mesh = {*Biofilms ; Candida/classification/genetics/isolation & purification/*physiology ; Humans ; Mycoses/*microbiology ; Yeasts/classification/genetics/isolation & purification/*physiology ; }, abstract = {To colonize and infect the host, arthroconidial yeasts must avoid being killed by the host's defenses. The formation of biofilms on implanted devices allows fungi to avoid host responses and to disseminate into the host. To better study the mechanisms of infection by arthroconidial yeasts, adherence and biofilm formation were assayed using patient samples collected over 10 years. In clinical samples, adherence varies within species, but the relative adherence is constant for those samples isolated from the same infection site. Herein we document, for the first time, in-vitro biofilm formation by Trichosporon dohaense, T. ovoides, T. japonicum, T. coremiiforme, Cutaneotrichosporon mucoides, Cutaneotrichosporon cutaneum, Galactomyces candidus, and Magnusiomyces capitatus on clinically relevant catheter material. Analysis of biofilm biomass assays indicated that biofilm mass changes less than 2-fold, regardless of the species. Our results support the hypothesis that most pathogenic fungi can form biofilms, and that biofilm formation is a source of systemic infections.}, } @article {pmid34231118, year = {2021}, author = {Wang, F and Liu, H and Li, J and Zhang, W and Jiang, B and Xuan, H}, title = {Australian propolis ethanol extract exerts antibacterial activity against methicillin-resistant Staphylococcus aureus by mechanisms of disrupting cell structure, reversing resistance, and resisting biofilm.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {4}, pages = {1651-1664}, pmid = {34231118}, issn = {1678-4405}, support = {NO. 31672499//the National Natural Science Foundation of China/ ; SDAIT-24-05//the Modern Agricultural Technology System of Shandong Province/ ; No. 318051826//the Doctoral Research Foundation of Liaocheng University/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Australia ; Biofilms/drug effects ; Ethanol/chemistry ; *Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; *Propolis/chemistry/pharmacology ; }, abstract = {The antibacterial activity and mechanisms of Australian propolis ethanol extract (APEE) against methicillin-resistant Staphylococcus aureus (MRSA) were investigated herein. The diameter of inhibition zones (DIZ) of APEE was 19.7 mm, while the minimum inhibition concentration (MIC) and minimum bactericide concentration (MBC) of APEE were both 0.9 mg/mL against the tested strain of MRSA. Nucleic acid leakage and propidium iodide (PI) staining assays showed that APEE can stimulate the release of intracellular nucleic acids by disrupting the integrity of the cell wall and cytoplasmic membrane. Scanning electron microscopy (SEM) further confirmed that APEE could depress cellular activities via damaging the cell structure, including the cell wall and membrane. Western blot analysis and β-lactamase activity assay showed that APEE could inhibit the expression of PBP2a and reduce the activity of β-lactamase, suggesting that APEE is able to reverse the drug resistance of MRSA. XTT and crystal violet (CV) assays indicated that APEE had the capacity to prevent the formation of biofilms through decreasing cellular activities and biomass. Bacterial adhesion assay revealed that APEE could reduce the adhesive capacity of the strain, belonging to its antibiofilm mechanisms. Furthermore, nine main compounds of APEE were identified and quantified by HPLC-DAD/Q-TOF-MS. The results above all verified that the antibacterial activity of APEE against MRSA was mainly due to disrupting cell structure, reversing resistance, and resisting biofilm formation, which indicates that APEE is expected to be an efficient functional ingredient with great potential application in the field of medicine and food.}, } @article {pmid34229320, year = {2021}, author = {Jiang, Y and Xu, Q and Jiang, L and Zheng, R}, title = {Isolation and Characterization of a Lytic Staphylococcus aureus Phage WV against Staphylococcus aureus Biofilm.}, journal = {Intervirology}, volume = {64}, number = {4}, pages = {169-177}, pmid = {34229320}, issn = {1423-0100}, mesh = {*Bacteriophages/genetics ; Biofilms ; China ; Humans ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {BACKGROUND: Staphylococcus aureus is a Gram-positive, pathogenic bacterium that causes a wide range of symptoms in humans and can form biofilm, which is a multicellular community of microorganisms that attaches to nonbiological and biological surfaces.

METHODS: Here, we aimed to isolate and characterize an S. aureus phage and examine the bactericidal activity alone and in conjunction with streptomycin treatment.

RESULTS: We isolated a virulent phage, WV, from a slaughterhouse in Jiangsu, China. This strain belonged to the family Myoviridae and presented a genome size of 141,342 bp. The optimal pH of the preservation buffer was 6-7, optimal growth temperature was 37°C, and optimal multiplicity of infection was 0.01. Phage WV can sterilize most clinical strains of S. aureus that had been isolated from clinical patients in the First People's Hospital of the Yunnan Province. Against low-concentration S. aureus culture, streptomycin demonstrated a greater antibiofilm effect than that of phage WV. By contrast, in high-concentration S. aureus culture, phage WV demonstrated greater antibiofilm effect than that of streptomycin. The use of phage WV and streptomycin together had a substantially greater overall antibiofilm effect than that achieved using either component alone.

CONCLUSION: This study provides strong evidence for the effectiveness of phage application for the reduction of S. aureus biofilm growth and suggests that phages can be considered as a viable alternative to antibiotics in clinical settings.}, } @article {pmid34228832, year = {2021}, author = {Ahmed, NH and Xess, I and Singh, G and Satpathy, G and Sharma, N and Agarwal, T and Hussain, T and Chawla, R and Tandon, R}, title = {Species identification, antifungal susceptibility profiles and biofilm formation attributes of Rhodotorula isolates from ocular infections.}, journal = {Mycoses}, volume = {64}, number = {10}, pages = {1183-1196}, doi = {10.1111/myc.13349}, pmid = {34228832}, issn = {1439-0507}, support = {A-686//Research Section, All India Institute of Medical Sciences, New Delhi/ ; }, mesh = {Amphotericin B ; *Antifungal Agents/pharmacology/therapeutic use ; Biofilms/drug effects ; *Eye Infections/drug therapy/microbiology ; Flucytosine ; Humans ; Microbial Sensitivity Tests ; Natamycin ; Prospective Studies ; *Rhodotorula/drug effects/genetics ; }, abstract = {BACKGROUND: Members of genus Rhodotorula are widely distributed in nature and have been traditionally considered non-pathogenic. Last few decades have seen the yeast as an emerging pathogen. We observed increase in numbers of Rhodotorula isolates from ocular infections in last few years, thus this prospective study was planned.

OBJECTIVES: To identify the species of Rhodotorula isolates from ocular infections. To know the antifungal susceptibilities and study the biofilm formation attributes of the isolates.

MATERIALS AND METHODS: Rhodotorula isolates were speciated using conventional methods, Matrix Assisted Laser Desorption and Ionisation - Time of Flight (MALDI- TOF) and sequencing of ITS region of ribosomal DNA. Antifungal susceptibility testing (AFST) was done using disc diffusion and E-test. Biofilm formation was studied using XTT [2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetra-zolium-5-carboxanilide] assay.

RESULTS: Twenty four isolates (92.3%) were identified as R. mucilaginosa and two as R. Minuta. AFST showed high MICs against Fluconazole, Amphotericin-B, Caspofungin, Micafungin and Flucytosine; MIC distribution from low to very high against Voriconazole, Itraconazole and Natamycin; and very low MICs against Posaconazole 57.7% of isolates were strong biofilm producers, 23.1% were moderate, and 19.2% were non producers.

CONCLUSIONS: This is the first prospective study on species distribution, antifungal susceptibility and biofilm production attributes of Rhodotorula isolates from ocular infections; also first time demonstrating the utility of proteomics based MALDI-TOF in diagnosing Rhodotorula up to species level. The study has shown high MICs against the conventional azoles, Amphotericin-B and Flucytosine. However, low MICs against Posaconazole and Natamycin give a hope for their possible therapeutic use.}, } @article {pmid34227933, year = {2021}, author = {Tomlinson, BR and Malof, ME and Shaw, LN}, title = {A global transcriptomic analysis of Staphylococcus aureus biofilm formation across diverse clonal lineages.}, journal = {Microbial genomics}, volume = {7}, number = {7}, pages = {}, pmid = {34227933}, issn = {2057-5858}, support = {R01 AI124458/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Adhesion/*genetics ; Biofilms/*growth & development ; Community-Acquired Infections/microbiology ; Cross Infection/microbiology ; DNA, Bacterial/genetics ; Gene Expression Profiling ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/*genetics/*growth & development/isolation & purification ; Polysaccharides, Bacterial/*biosynthesis ; Staphylococcal Infections/pathology ; Transcriptome/genetics ; }, abstract = {A key characteristic of Staphylococcus aureus infections, and one that also varies phenotypically between clones, is that of biofilm formation, which aids in bacterial persistence through increased adherence and immune evasion. Though there is a general understanding of the process of biofilm formation - adhesion, proliferation, maturation and dispersal - the tightly orchestrated molecular events behind each stage, and what drives variation between S. aureus strains, has yet to be unravelled. Herein we measure biofilm progression and dispersal in real-time across the five major S. aureus CDC-types (USA100-USA500) revealing adherence patterns that differ markedly amongst strains. To gain insight into this, we performed transcriptomic profiling on these isolates at multiple timepoints, compared to planktonically growing counterparts. Our findings support a model in which eDNA release, followed by increased positive surface charge, perhaps drives initial abiotic attachment. This is seemingly followed by cooperative repression of autolysis and activation of poly-N-acetylglucosamine (PNAG) production, which may indicate a developmental shift in structuring the biofilm matrix. As biofilms mature, diminished translational capacity was apparent, with 53 % of all ribosomal proteins downregulated, followed by upregulation of anaerobic respiration enzymes. These findings are noteworthy because reduced cellular activity and an altered metabolic state have been previously shown to contribute to higher antibiotic tolerance and bacterial persistence. In sum, this work is, to our knowledge, the first study to investigate transcriptional regulation during the early, establishing phase of biofilm formation, and to compare global transcriptional regulation both temporally and across multiple clonal lineages.}, } @article {pmid34226590, year = {2021}, author = {Karki, AB and Ballard, K and Harper, C and Sheaff, RJ and Fakhr, MK}, title = {Staphylococcus aureus enhances biofilm formation, aerotolerance, and survival of Campylobacter strains isolated from retail meats.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {13837}, pmid = {34226590}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Campylobacter coli/genetics/growth & development/pathogenicity ; Campylobacter jejuni/*genetics/growth & development/pathogenicity ; Coinfection/genetics/microbiology ; Food Microbiology ; Humans ; Meat/*microbiology ; Meat Products/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*genetics/growth & development/pathogenicity ; }, abstract = {In retail meat products, Campylobacter jejuni, C. coli, and Staphylococcus aureus have been reported in high prevalence. The polymicrobial interaction between Campylobacter and other bacteria could enhance Campylobacter survival during the adverse conditions encountered during retail meat processing and storage. This study was designed to investigate the potential role of S. aureus from retail meats in enhancing the survival of Campylobacter exposed to low temperature, aerobic conditions, and biofilm formation. Results indicated that viable S. aureus cells and filter-sterilized cell-free media obtained from S. aureus prolonged the survival of Campylobacter at low temperature and during aerobic conditions. Biofilm formation of Campylobacter strains was significantly enhanced in the presence of viable S. aureus cells, but the results were inconclusive when extracts from cell-free media were used. In conclusion, the presence of S. aureus cells enhances survivability of Campylobacter strains in adverse conditions such as low temperature and aerobic conditions. Further investigations are warranted to understand the interaction between Campylobacter and S. aureus, and effective intervention strategies are needed to reduce the incidence of both foodborne pathogens in retail meat products.}, } @article {pmid34225870, year = {2021}, author = {Yu, M and Zhang, G and Li, P and Lu, H and Tang, W and Yang, X and Huang, R and Yu, F and Wu, W and Xiao, Y and Xing, X}, title = {Acid-activated ROS generator with folic acid targeting for bacterial biofilm elimination.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {127}, number = {}, pages = {112225}, doi = {10.1016/j.msec.2021.112225}, pmid = {34225870}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; *Folic Acid ; *Metal-Organic Frameworks ; Reactive Oxygen Species ; }, abstract = {Many medical and chemical applications require the precise supply of antimicrobial components in a controlled manner at the location of mature biofilm deposits. This work reports a facile strategy to fabricate nanoscale metal-organic frameworks (NMOFs) coencapsulating the antibacterial ligand (lysine carbon dots, Lys-CDs) and targeted drug (folic acid, FA) in one pot to improve antibiofilm efficiency against established biofilms. The resulting products are characterized by transmission electron microscopy, field-emission scanning electron microscopy, powder x-ray diffraction, and ultraviolet-visible spectroscopy. The results show that Lys-CDs could coordinate with Zn[2+] and the adding of FA inhibits the coordination of Lys-CDs with central ions of Zn. The Lys-CDs and FA are successfully exposed with the NMOFs disintegrating in the acid environment of bacterial metabolites. We are surprised to find a sharp increase of reactive oxygen species (ROS) inside the bacterial cells by FA functionalizing NMOFs, which undoubtedly enhance the antibacterial and antibiofilm activity. The as-synthesized ZIF-8-based nanocomposites also show the peroxidase-like activity in an acid environment, and produce extremely active hydroxyl radicals resulting in the improved antibacterial and antibiofilm activity. The possible mechanisms of antibacterial activities indicate that the presence of FA is significant in the sense of targeting bacteria. This study shows a novel approach to construct acid stimulation supply system which may be helpful for the research of antibiofilms.}, } @article {pmid34225500, year = {2021}, author = {Ruiz-Sorribas, A and Poilvache, H and Kamarudin, NHN and Braem, A and Van Bambeke, F}, title = {In vitro polymicrobial inter-kingdom three-species biofilm model: influence of hyphae on biofilm formation and bacterial physiology.}, journal = {Biofouling}, volume = {37}, number = {5}, pages = {481-493}, doi = {10.1080/08927014.2021.1919301}, pmid = {34225500}, issn = {1029-2454}, mesh = {Bacterial Physiological Phenomena ; *Biofilms ; Candida albicans ; Humans ; *Hyphae ; Staphylococcus aureus ; }, abstract = {Biofilms are an important medical burden, notably for patients with orthopaedic device-related infections. When polymicrobial, these infections are more lethal and recalcitrant. Inter-kingdom biofilm infections are poorly understood and challenging to treat. Here, an in vitro three-species model including Staphylococcus aureus, Escherichia coli and Candida albicans was developed, to represent part of the diversity observed in orthopaedic infections or other clinical contexts. The importance of fungal hyphae for biofilm formation and virulence factor expression was explored. Two protocols were set up, allowing, or not, for hyphal formation. Culturable cells and biomass were characterised in both models, and biofilms were imaged in bright-field, confocal and electron microscopes. The expression of genes related to virulence, adhesion, exopolysaccharide synthesis and stress response was analysed in early-stage and mature biofilms. It was found that biofilms enriched in hyphae had larger biomass and showed higher expression levels of genes related to bacterial virulence or exopolysaccharides synthesis.}, } @article {pmid34225118, year = {2021}, author = {Su, G and Li, S and Deng, X and Hu, L and Praburaman, L and He, Z and Zhong, H and Sun, W}, title = {Low concentration of Tween-20 enhanced the adhesion and biofilm formation of Acidianus manzaensis YN-25 on chalcopyrite surface.}, journal = {Chemosphere}, volume = {284}, number = {}, pages = {131403}, doi = {10.1016/j.chemosphere.2021.131403}, pmid = {34225118}, issn = {1879-1298}, mesh = {*Acidianus ; Bacterial Adhesion ; Biofilms ; Copper ; Polysorbates ; }, abstract = {Although Tween-20 was used as an important catalyst to increase chalcopyrite bioleaching rate by acidophiles, the effect of Tween-20 on initial adhesion and biofilm development of acidophiles on chalcopyrite has not been explored until now. Herein, the role of Tween-20 in early attachment behaviors and biofilm development by Acidianus manzaensis strain YN-25 were investigated by adhesion experiments, adhesion force measurement, visualization of biofilm assays and a series of analyses including extended Derjaguin Landau Verwey Overbeek (DLVO) theory, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The bacterial adhesion experiments showed that 2 mg/L of Tween-20 increased the adhesion percentage (by 8%) of A. manzaensis YN-25. Tween-20 could promote the early adhesion of A. manzaensis YN-25 by changing the Lewis acid-base interaction and electrostatic force to increase total interaction energy and adhesion force. Besides, the functional groups on the surface of cells (carboxyl, hydroxyl and amino functional groups) contributed to the adhesion of A. manzaensis YN-25 on chalcopyrite. Furthermore, the promotion of biofilm formation by Tween-20 was mainly attributed to the reduction of S[0] passivation layer formation and complexing more Fe[3+] on chalcopyrite surface, contributing to the erosion of chalcopyrite and creating more corrosion pits. Live/dead staining showed low live/dead ratio (ranged from 0.35 to 1.32) during the biofilm development process. This report offers a better understanding of the effects of Tween-20 on attachment and biofilm development of acidophilic microorganisms and would lay a theoretical foundation for the better application of catalyst in bioleaching.}, } @article {pmid34223738, year = {2021}, author = {Kodori, M and Nikmanesh, B and Hakimi, H and Ghalavand, Z}, title = {Antibiotic Susceptibility and Biofilm Formation of Bacterial Isolates Derived from Pediatric Patients with Cystic Fibrosis from Tehran, Iran.}, journal = {Archives of Razi Institute}, volume = {76}, number = {2}, pages = {397-406}, pmid = {34223738}, issn = {2008-9872}, mesh = {Female ; Male ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cross-Sectional Studies ; *Cystic Fibrosis/drug therapy/microbiology ; Iran/epidemiology ; *Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; Humans ; Child, Preschool ; Drug Resistance, Bacterial ; }, abstract = {Cystic fibrosis (CF) is a genetic disease with a high rate of morbidity and mortality. Children with CF commonly suffer from recurrent and persistent pulmonary tract infections caused by diverse bacterial pathogens. This study aimed to investigate the prevalence, antimicrobial susceptibility, and biofilm formation of bacterial isolates in pediatric patients with CF. The study population of this cross-sectional study included 8,908 children suspected to have CF by clinical manifestations from March 2015 to August 2017 who were referred to the Tehran Pediatric Central Hospital, Iran. The tests carried out for each participant included screening sweat test, sputum culture, antibiotic susceptibility test using Kirby-Bauer disk diffusion method, and biofilm formation in microtiter plates method. Based onclinical examination and screening sweat test, 183 (2.05 %(out of 8,908 children, were positive for CF. The mean age of children was estimated at 2.93 years, and the majority of them were male (n=103, 56.2%). No gender-specific difference was observed in CF disease in this study (P>0.05). In addition, the results of sputum culture showed that 153 (83.6%) microorganisms (bacteria and fungi) were collected from CF patients. Normal flora was isolated in 30 (16.4%) patients and more than one bacterial species were isolated in 7.2% of patients. The obtained results indicated that Pseudomonas aeruginosa was the most prevalent isolated bacteria followed by Staphylococcus aureus, and Klebsiella pneumoniae. Based on the antibiotic susceptibility test results, P. aeruginosa and piperacillin/tazobactam had the highest (11.7%) and the lowest (2.3%) resistance rate against gentamicin, respectively. However, all K. pneumoniae isolates were resistant to Cefotaxime. Among S. aureus isolates, 83.4% and 16.6% were methicillin-susceptible Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus respectively. Concerning biofilm formation, 76%, 67%, and 72.5% of P. aeruginosa, S. aureus, and K. pneumoniae isolates were biofilm producers, respectively. Based on the study results, P. aeruginosa was the dominant pathogen in pediatric patients with CF from Tehran, Iran, and most of the pathogens were biofilm producers. No severe antibiotic resistance was observed in the isolates; however, the anti-microbial resistance profile should be carefully checked in CF patients on a regular basis.}, } @article {pmid34222225, year = {2021}, author = {Lerche, CJ and Schwartz, F and Theut, M and Fosbøl, EL and Iversen, K and Bundgaard, H and Høiby, N and Moser, C}, title = {Anti-biofilm Approach in Infective Endocarditis Exposes New Treatment Strategies for Improved Outcome.}, journal = {Frontiers in cell and developmental biology}, volume = {9}, number = {}, pages = {643335}, pmid = {34222225}, issn = {2296-634X}, abstract = {Infective endocarditis (IE) is a life-threatening infective disease with increasing incidence worldwide. From early on, in the antibiotic era, it was recognized that high-dose and long-term antibiotic therapy was correlated to improved outcome. In addition, for several of the common microbial IE etiologies, the use of combination antibiotic therapy further improves outcome. IE vegetations on affected heart valves from patients and experimental animal models resemble biofilm infections. Besides the recalcitrant nature of IE, the microorganisms often present in an aggregated form, and gradients of bacterial activity in the vegetations can be observed. Even after appropriate antibiotic therapy, such microbial formations can often be identified in surgically removed, infected heart valves. Therefore, persistent or recurrent cases of IE, after apparent initial infection control, can be related to biofilm formation in the heart valve vegetations. On this background, the present review will describe potentially novel non-antibiotic, antimicrobial approaches in IE, with special focus on anti-thrombotic strategies and hyperbaric oxygen therapy targeting the biofilm formation of the infected heart valves caused by Staphylococcus aureus. The format is translational from preclinical models to actual clinical treatment strategies.}, } @article {pmid34222041, year = {2021}, author = {Fan, C and Gu, H and Liu, L and Zhu, H and Yan, J and Huo, Y}, title = {Distinct Microbial Community of Accumulated Biofilm in Dental Unit Waterlines of Different Specialties.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {670211}, pmid = {34222041}, issn = {2235-2988}, mesh = {Biofilms ; Child ; Colony Count, Microbial ; Equipment Contamination ; Humans ; *Microbiota ; *Water Microbiology ; }, abstract = {The contamination of dental unit waterlines (DUWLs) is a serious problem and directly affects the dental care. This study aims to explore the microbial community of biofilm in DUWL from different specialties and investigate the associated factors. A total of 36 biofilm samples from 18 DUWL of six specialties (i.e., prosthodontics, orthodontics, pediatrics, endodontics, oral surgery, and periodontics) at two time points (i.e., before and after daily dental practice) were collected with a novel method. Genomic DNA of samples was extracted, and then 16S ribosomal DNA (rDNA) (V3-V4 regions) and ITS2 gene were amplified and sequenced. Kruskal-Wallis and Wilcoxon rank test were adopted for statistical analysis. Microbial community with high diversity of bacteria (631 genera), fungi (193 genera), and viridiplantae was detected in the biofilm samples. Proteobacteria was the dominant bacteria (representing over 65.74-95.98% of the total sequences), and the dominant fungi was Ascomycota (93.9-99.3%). Microorganisms belonging to multiple genera involved in human diseases were detected including 25 genera of bacteria and eight genera of fungi, with relative abundance of six genera over 1% (i.e., Acinetobacter, Pseudomonas, Enterobacter, Aspergillus, Candida, and Penicillium). The biofilm microbiome may be influenced by the characteristics of dental specialty and routine work to some extent. The age of dental chair unit and overall number of patients had the strongest impact on the overall bacteria composition, and the effect of daily dental practices (associated with number of patients and dental specialty) on the fungi composition was the greatest. For the first time, biofilm in DUWL related to dental specialty was comprehensively evaluated, with more abundance of bacterial and fungal communities than in water samples. Biofilm accumulation with daily work and multiple kinds of opportunistic pathogen emphasized the infectious risk with dental care and the importance of biofilm control.}, } @article {pmid34221021, year = {2021}, author = {Karimi, K and Zarei, O and Sedighi, P and Taheri, M and Doosti-Irani, A and Shokoohizadeh, L}, title = {Investigation of Antibiotic Resistance and Biofilm Formation in Clinical Isolates of Klebsiella pneumoniae.}, journal = {International journal of microbiology}, volume = {2021}, number = {}, pages = {5573388}, pmid = {34221021}, issn = {1687-918X}, abstract = {AIM: Klebsiella pneumoniae (K. pneumoniae) is an encapsulated Gram-negative bacterium that can lead to 14-20% of nosocomial infections. The ability of biofilm formation in this bacterium decreases the host immune response and antibiotic efficacy. This may impose a huge impact on patients and healthcare settings. This study aimed to evaluate the antibiotic resistance pattern and biofilm formation in K. pneumoniae strains isolated from two major Hamadan hospitals, west of Iran.

METHODS: A total of 83 K. pneumoniae strains were isolated from clinical samples of patients in different wards of Hamadan hospitals from September 2018 to March 2019. Determination of antimicrobial susceptibility was performed using the disk diffusion method. Biofilm formation was evaluated by the crystal violet method. Data were analyzed by the SPSS software and chi-square test.

RESULTS: The results showed that clinical samples included 18 urinary tract samples (22%), 6 wound samples (7%), 6 blood samples (7%), 17 tracheal tube aspiration samples (20%), 32 throat cultures (38%), 2 sputum samples (2.5%), and 2 abscess drain cultures (2.5%). High-level resistance to cefotaxime was detected in 92%, and all of isolates were susceptible to colistin. Biofilm formation was seen in 62 (75%) isolates. Strong biofilm formation was observed in 17 (20%) strains. A significant correlation was seen between biofilm formation and antibiotic resistance (P value <0.05).

CONCLUSION: Our findings emphasize the need for proper diagnosis, control, and treatment of infections caused by K. pneumoniae especially in respiratory tract infections due to the strong biofilm formation and high antibiotic resistance in these strains.}, } @article {pmid34220852, year = {2021}, author = {Heidrich, V and Bruno, JS and Knebel, FH and de Molla, VC and Miranda-Silva, W and Asprino, PF and Tucunduva, L and Rocha, V and Novis, Y and Arrais-Rodrigues, C and Fregnani, ER and Camargo, AA}, title = {Dental Biofilm Microbiota Dysbiosis Is Associated With the Risk of Acute Graft-Versus-Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {692225}, pmid = {34220852}, issn = {1664-3224}, mesh = {Adult ; Aged ; Bacteria/genetics/*growth & development ; Dysbiosis ; Female ; Graft vs Host Disease/diagnosis/immunology/*microbiology ; Hematopoietic Stem Cell Transplantation/*adverse effects ; Humans ; Male ; Middle Aged ; Mouth/*microbiology ; Ribotyping ; Risk Assessment ; Risk Factors ; Time Factors ; Transplantation, Homologous/adverse effects ; Treatment Outcome ; Young Adult ; }, abstract = {Acute graft-versus-host disease (aGVHD) is one of the major causes of death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recently, aGVHD onset was linked to intestinal microbiota (IM) dysbiosis. However, other bacterial-rich gastrointestinal sites, such as the mouth, which hosts several distinctive microbiotas, may also impact the risk of GVHD. The dental biofilm microbiota (DBM) is highly diverse and, like the IM, interacts with host cells and modulates immune homeostasis. We characterized changes in the DBM of patients during allo-HSCT and evaluated whether the DBM could be associated with the risk of aGVHD. DBM dysbiosis during allo-HSCT was marked by a gradual loss of bacterial diversity and changes in DBM genera composition, with commensal genera reductions and potentially pathogenic bacteria overgrowths. High Streptococcus and high Corynebacterium relative abundance at preconditioning were associated with a higher risk of aGVHD (67% vs. 33%; HR = 2.89, P = 0.04 and 73% vs. 37%; HR = 2.74, P = 0.04, respectively), while high Veillonella relative abundance was associated with a lower risk of aGVHD (27% vs. 73%; HR = 0.24, P < 0.01). Enterococcus faecalis bloom during allo-HSCT was observed in 17% of allo-HSCT recipients and was associated with a higher risk of aGVHD (100% vs. 40%; HR = 4.07, P < 0.001) and severe aGVHD (60% vs. 12%; HR = 6.82, P = 0.01). To the best of our knowledge, this is the first study demonstrating that DBM dysbiosis is associated with the aGVHD risk after allo-HSCT.}, } @article {pmid34220733, year = {2021}, author = {Hassett, DJ and Kovall, RA and Schurr, MJ and Kotagiri, N and Kumari, H and Satish, L}, title = {The Bactericidal Tandem Drug, AB569: How to Eradicate Antibiotic-Resistant Biofilm Pseudomonas aeruginosa in Multiple Disease Settings Including Cystic Fibrosis, Burns/Wounds and Urinary Tract Infections.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {639362}, pmid = {34220733}, issn = {1664-302X}, abstract = {The life-threatening pandemic concerning multi-drug resistant (MDR) bacteria is an evolving problem involving increased hospitalizations, billions of dollars in medical costs and a remarkably high number of deaths. Bacterial pathogens have demonstrated the capacity for spontaneous or acquired antibiotic resistance and there is virtually no pool of organisms that have not evolved such potentially clinically catastrophic properties. Although many diseases are linked to such organisms, three include cystic fibrosis (CF), burn/blast wounds and urinary tract infections (UTIs), respectively. Thus, there is a critical need to develop novel, effective antimicrobials for the prevention and treatment of such problematic infections. One of the most formidable, naturally MDR bacterial pathogens is Pseudomonas aeruginosa (PA) that is particularly susceptible to nitric oxide (NO), a component of our innate immune response. This susceptibility sets the translational stage for the use of NO-based therapeutics during the aforementioned human infections. First, we discuss how such NO therapeutics may be able to target problematic infections in each of the aforementioned infectious scenarios. Second, we describe a recent discovery based on years of foundational information, a novel drug known as AB569. AB569 is capable of forming a "time release" of NO from S-nitrosothiols (RSNO). AB569, a bactericidal tandem consisting of acidified NaNO2 (A-NO2 [-]) and Na2-EDTA, is capable of killing all pathogens that are associated with the aforementioned disorders. Third, we described each disease state in brief, the known or predicted effects of AB569 on the viability of PA, its potential toxicity and highly remote possibility for resistance to develop. Finally, we conclude that AB569 can be a viable alternative or addition to conventional antibiotic regimens to treat such highly problematic MDR bacterial infections for civilian and military populations, as well as the economical burden that such organisms pose.}, } @article {pmid34218787, year = {2021}, author = {Yuan, M and Sun, T and Wu, J and Fei, Y and Yang, Y and Ling, Y and Zhang, Y and Huang, Z}, title = {The Insights and Perspectives of Nitric Oxide-mediated Biofilm Eradication.}, journal = {Current topics in medicinal chemistry}, volume = {21}, number = {24}, pages = {2213-2229}, doi = {10.2174/1568026621666210701113043}, pmid = {34218787}, issn = {1873-4294}, support = {81822041, 21977116, 81773573//National Natural Science Foundation of China/ ; SKLNMZZCX201824, SKLNMZZ202029//State Key Laboratory of Natural Medicines/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Humans ; Nitric Oxide/*pharmacology/therapeutic use ; }, abstract = {Biofilms are among the most important causes of nosocomial and recurrent infections as biofilms confer antibiotic resistance to pathogenic bacteria and protect them from the host's immune system. Thus, it is imperative to investigate effective therapeutic agents to counteract biofilms. As an important signaling molecule, Nitric Oxide (NO) plays a crucial role in various biological and pathological processes. NO could disperse biofilm and restore the drug sensitivity by reducing intracellular cyclic-diguanosine monophosphate (c-di-GMP) levels. This review highlights recent advances on antibacterial and antibiofilm effects of NO when NO was co-administered with other antimicrobial agents. A significant improvement in drug permeability and biofilm cell targeting and reduced cytotoxicity could be attained with this strategy. In this review, we briefly lay out challenges and propose future directions in this appealing avenue of research on NO-based therapy for biofilm eradication.}, } @article {pmid34218516, year = {2022}, author = {Vouros, I and Antonoglou, GN and Anoixiadou, S and Kalfas, S}, title = {A novel biofilm removal approach (Guided Biofilm Therapy) utilizing erythritol air-polishing and ultrasonic piezo instrumentation: A randomized controlled trial.}, journal = {International journal of dental hygiene}, volume = {20}, number = {2}, pages = {381-390}, doi = {10.1111/idh.12533}, pmid = {34218516}, issn = {1601-5037}, support = {//Research Committee, Aristotle University of Thessaloniki/ ; }, mesh = {Biofilms ; Dental Scaling ; *Erythritol ; Humans ; Powders ; Root Planing ; *Ultrasonic Therapy ; Ultrasonics ; }, abstract = {OBJECTIVE: To evaluate the effectiveness of biofilm removal of a treatment protocol combining an air-abrasive device using erythritol powder (AIRFLOW®) and an ultrasonic piezon instrumentation (Guided Biofilm Therapy/GBT) compared with the conventional mechanical approach (Scaling and Root Planing/SRP) during supportive periodontal treatment (SPT).

MATERIALS AND METHODS: Fifty patients, scheduled for supportive periodontal treatment at the Department of Preventive Dentistry, Periodontology and Implant Biology of the Aristotle University of Thessaloniki were randomly assigned to either a GBT (group A: 24 participants) or a SRP (Group B: 26 participants) treatment protocol. Therapeutic interventions and clinical measurements were performed at baseline and repeated at 6 weeks. Oral hygiene instructions were reinforced at each visit. A questionnaire was handed to the participants for evaluation of patient perception of both utilized approaches.

RESULTS: At 6 weeks, the two groups showed statistically significant reduction in plaque score and in gingival bleeding index compared with baseline. GBT required approximately 15% less chair-time than SRP with a mean difference of 5.1 min, which was statically significant (p = 0.049). Patient perception was more favourable for GBT than SRP.

CONCLUSIONS: Biofilm removal using erythritol AIRFLOW® and ultrasonic piezo-electric instruments (GBT) can be considered equally efficient compared with the conventional SRP. Moreover, GBT seemed to require shorter treatment time and to exhibit a more favourable patient perception than the conventional approach.}, } @article {pmid34218096, year = {2021}, author = {Yang, C and Lu, L and Liao, L and Zhang, B and Zeng, M and Zou, K and Liu, X and Zhang, M}, title = {Establishment of GC-MS method for the determination of Pseudomonas aeruginosa biofilm and its application in metabolite enrichment analysis.}, journal = {Journal of chromatography. B, Analytical technologies in the biomedical and life sciences}, volume = {1179}, number = {}, pages = {122839}, doi = {10.1016/j.jchromb.2021.122839}, pmid = {34218096}, issn = {1873-376X}, mesh = {*Biofilms ; Biomarkers/analysis/chemistry/metabolism ; Gas Chromatography-Mass Spectrometry/*methods ; Limit of Detection ; Linear Models ; Metabolome/*physiology ; *Pseudomonas aeruginosa/chemistry/metabolism ; Reproducibility of Results ; Signal Transduction/physiology ; }, abstract = {PA forms a biofilm resistant to antibiotics, hindering antibiotics efficacy and preventing the eradication of PA, has attracted much attention for its biofilm. In this study, we first established and validated an efficient and sensitive gas chromatography-mass spectrometry (GC-MS) method for the quantification of metabolites in biofilm. Decanoic acid was used as the internal standard. The separation of Palmitic acid, stearic acid and Decanoic acid was conducted on an Elite-5 MS column (30 m × 0.25 mm, 0.25 μm) using gradient elution condition at a flow rate of 1 mL/min. Palmitic acid, stearic acid and Decanoic acid were determined under the positive ionization mode, respectively. The calibration curve of Palmitic acid and stearic acid were established in the range of 4 to 128 μg/mL (r[2] = 0.999). The recovery of palmitic acid and stearic acid were between 98.76% and 113.91%, RSD ＜ 5%. The well validated method was used to detect the metabolites of Pseudomonas aeruginosa biofilm. 54 metabolites were isolated and identified from biofilm samples, and 7 important signal pathways were identified by KEGG enrichment analysis. ABC transporters and bacterial chemotaxis signaling pathways have an important impact on the growth of PA biofilm among these metabolic pathways. This study provides valuable references for the further study of PA biofilm, especially the change of metabolite content and the search for biomarkers.}, } @article {pmid34217924, year = {2021}, author = {Parsania, S and Mohammadi, P and Soudi, MR}, title = {Biotransformation and removal of arsenic oxyanions by Alishewanella agri PMS5 in biofilm and planktonic states.}, journal = {Chemosphere}, volume = {284}, number = {}, pages = {131336}, doi = {10.1016/j.chemosphere.2021.131336}, pmid = {34217924}, issn = {1879-1298}, mesh = {*Alteromonadaceae ; *Arsenic ; Biofilms ; Biotransformation ; Humans ; Oxidation-Reduction ; Plankton ; }, abstract = {Arsenic oxyanions are toxic chemicals that impose a high risk to humans and other living organisms in the environment. The present study investigated indigenous heterotrophic bacteria in the tailings dam effluent (TDE) of a gold mining factory. Thirty-seven arsenic resistant bacteria were cultured on Reasoner's 2A agar supplemented with arsenic salts through filtration. One strain encoded as PMS5 with the highest resistance to 140-mM sodium arsenite and 600-mM sodium arsenate in tryptic soy broth was selected for further investigations. According to phenotypic examinations and 16S rDNA sequence analysis, PMS5 belonged to the genus Alishewanella and was sensitive to most of the examined antibiotics. The biosorption and bioaccumulation abilities of arsenic salts were observed in this isolate based on Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) and biosorption and bioaccumulation data. PMS5 was also found to cause the volatilization and biotransformation of arsenic oxyanions through their oxidation and reduction. Moreover, the contribution of PMS5 to arsenic (3[+], 5[+]) bioprocessing under oligotrophic conditions was confirmed in fixed-bed reactors fed with the TDE of the gold factory (R1) and synthetic water containing As[5+] (R2). According to biofilm assays such as biofilm staining, cell count, detachment assay and SEM, the arsenic significantly reduced the biofilm density of the examined reactors compared to that of the control (R3). Arsenate reduction and arsenite oxidation under bioreactor conditions were respectively obtained as 75.5-94.7% and 8%. Furthermore, negligible arsenic volatilization (1.2 ppb) was detected.}, } @article {pmid34217606, year = {2021}, author = {Maeda, T and Fukushima, Y and Yoshida, H and Goto, M and Fujita, T and Tsuyuki, Y and Takahashi, T}, title = {Biofilm production ability and associated characteristics of Streptococcus agalactiae isolates from companion animals and humans.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {27}, number = {11}, pages = {1571-1577}, doi = {10.1016/j.jiac.2021.06.018}, pmid = {34217606}, issn = {1437-7780}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Female ; Genotype ; Humans ; Microbial Sensitivity Tests ; *Pets ; *Streptococcus agalactiae/genetics ; Virulence Factors/genetics ; }, abstract = {OBJECTIVE: We evaluated biofilm production ability (BPA) of Streptococcus agalactiae isolates from companion animals/humans and clarified the relationship between BPA populations and other microbiological features.

METHODS: Companion animal-/human-origin isolates were collected with host information. We measured BPA using crystal violet staining, via virulence-associated gene profiling (hylB-pavA-pilB-spb1-srtC1-brpA), capsular genotyping, multilocus sequence typing, and antimicrobial resistance (AMR) phenotyping/genotyping. Significant difference in BPA of isolates from different hosts was assessed. We analyzed the association between BPA populations and the virulence genotypes, capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes. Inhibitory effect of berberine on BPA was evaluated.

RESULTS: Five, twenty-six, and twenty-six isolates belonged to strong, moderate, and weak biofilm producers, whereas seventeen showed no biofilm production. We defined strong, moderate, or weak biofilm producers as the producer group (n = 57) to conduct a comparative analysis between the producer and non-producer populations. There was a significant correlation between the producer population and vaginal specimen. We found significant associations between the producer group and presence (57.9%) of pilB and between the non-producer population and presence (70.6%) of spb1. There was no association between the producer group and capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes (except for a significant correlation between the producer group and AMR to minocycline). We confirmed inhibitory effect of berberine at sub-minimum inhibitory concentrations (MICs) against the type strain on BPA.

CONCLUSION: Our observations suggest that S. agalactiae harboring pilB is more capable of producing biofilms, with berberine inhibitory effect at sub-MICs on BPA.}, } @article {pmid34216901, year = {2021}, author = {Ugya, AY and Ajibade, FO and Hua, X}, title = {The efficiency of microalgae biofilm in the phycoremediation of water from River Kaduna.}, journal = {Journal of environmental management}, volume = {295}, number = {}, pages = {113109}, doi = {10.1016/j.jenvman.2021.113109}, pmid = {34216901}, issn = {1095-8630}, mesh = {Biofilms ; *Microalgae ; Nigeria ; Rivers ; Water ; *Water Pollutants, Chemical ; }, abstract = {This study is aimed at investigating the efficiency of microalgae biofilm in the phycoremediation of water from a polluted river. Freshwater microalgae biofilm inherent in a contaminated petrochemical stream was employed to remediate water from the River Kaduna, which is the largest river in Kaduna town, Kaduna State, Nigeria, and serves as the primary water source in Kaduna town. The results indicate high reduction efficiency of some physicochemical parameters and pollutants (turbidity (71%), conductivity (9.8%), sulfate (37.5%), alkalinity (62.5%), chloride (11.5%), TDS (9.9%), TSS (66.7%), nitrate (42.9%), COD (24%), and BOD (33%), Cd (70.0%), Ni (74.0%) and Pb (71.0%)), indicating the effectiveness of microalgae biofilm in the phycoremediation of water from River Kaduna. According to scanning electron microscope (SEM) observation, the microalgae biofilm has rough surface morphology after the treatment of the river water, which implies that the biofilm was capable of removing the pollutants in water via biosorption. Other characterizations such as XRF, XRD, and FTIR also buttressed that biosorption was the primary removal mechanism of pollutants by microalgae biofilm. Besides, the results also show the production of ROS during the treatment of water from the River Kaduna by the microalgae biofilm. This high concentration of ROS produced during the treatment correlates significantly with pollutant degradation. The GC-MS analysis of the microalgae biofilm shows the involvement of some phytochemicals in the process of pollutant degradation. As a result, microalgae biofilm is a simple and cost-effective method of polluted water phycoremediation with promising applications and future prospects.}, } @article {pmid34216769, year = {2021}, author = {Kapustová, M and Puškárová, A and Bučková, M and Granata, G and Napoli, E and Annušová, A and Mesárošová, M and Kozics, K and Pangallo, D and Geraci, C}, title = {Biofilm inhibition by biocompatible poly(ε-caprolactone) nanocapsules loaded with essential oils and their cyto/genotoxicity to human keratinocyte cell line.}, journal = {International journal of pharmaceutics}, volume = {606}, number = {}, pages = {120846}, doi = {10.1016/j.ijpharm.2021.120846}, pmid = {34216769}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/toxicity ; Biofilms ; Cell Line ; DNA Damage ; Humans ; Keratinocytes ; Microbial Sensitivity Tests ; *Nanocapsules ; *Oils, Volatile/pharmacology ; Polyesters ; }, abstract = {Essential oils (EOs) of Thymus capitatus (Th) carvacrol chemotype and Origanum vulgare (Or) thymol and carvacrol chemotype were encapsulated in biocompatible poly(ε-caprolactone) nanocapsules (NCs). These nanosystems exhibited antibacterial, antifungal, and antibiofilm activities against Staphylococcus aureus, Escherichia coli, and Candida albicans. Th-NCs and Or-NCs were more effective against all tested strains than pure EOs and at the same time were not cytotoxic on HaCaT (T0020001) human keratinocyte cell line. The genotoxic effects of EO-NCs and EOs on HaCaT were evaluated using an alkaline comet assay for the first time, revealing that Th-NCs and Or-NCs did not induce DNA damage compared with untreated control HaCaT cells in vitro after 24 h. The cells morphological changes were assessed by label-free live cell Raman imaging. This study demonstrate the ability of poly(ε-caprolactone) nanocapsules loaded with thyme and oregano EOs to reduce microbial and biofilm growth and could be an ecological alternative in the development of new antimicrobial strategies.}, } @article {pmid34216663, year = {2021}, author = {Song, X and Wang, L and Liu, T and Liu, Y and Wu, X and Liu, L}, title = {Mandarin (Citrus reticulata L.) essential oil incorporated into chitosan nanoparticles: Characterization, anti-biofilm properties and application in pork preservation.}, journal = {International journal of biological macromolecules}, volume = {185}, number = {}, pages = {620-628}, doi = {10.1016/j.ijbiomac.2021.06.195}, pmid = {34216663}, issn = {1879-0003}, mesh = {Animals ; Bacterial Outer Membrane/drug effects ; Biofilms/drug effects ; Chitosan/*chemistry ; Citrus/*chemistry ; Escherichia coli/drug effects ; Food Preservation/*methods ; Nanoparticles ; Oils, Volatile/chemistry/*pharmacology ; Particle Size ; Plant Oils/chemistry/pharmacology ; *Pork Meat ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/drug effects ; Swine ; Thermogravimetry ; X-Ray Diffraction ; }, abstract = {Mandarin (Citrus reticulata L.) essential oil (MEO) reportedly displays excellent antimicrobial properties. In this study, MEO was loaded into chitosan nanoparticles (CSNPs). The characteristics, antibacterial properties and benefit in pork preservation of MEO-CSNPs were evaluated. The MEO-CSNPs displayed an excellent encapsulation efficiency (EE) (67.32%-82.35%), the particle size values of 131.3 nm-161.9 nm, and the absolute zeta potential values above 30 mV. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and thermogravimetric analysis (TGA) revealed that the MEO was incorporated into CSNPs without requiring a chemical reaction, the antibacterial activity of the MEO remained. Furthermore, the damage of MEO-chitosan nanoemulsions (MEO-CSs) to the cell membranes of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was confirmed by the change of bacterial cell morphology. The anti-biofilm assays verified that the MEO-CSs substantially inhibited biofilm formation and destroyed the mature biofilms. MEO-CSs were also applied to pork, proving a great potential for pork preservation. This study provides a potential approach for developing and utilizing MEO-CSs as natural antimicrobial agents in the food industry.}, } @article {pmid34215805, year = {2021}, author = {Allkja, J and van Charante, F and Aizawa, J and Reigada, I and Guarch-Pérez, C and Vazquez-Rodriguez, JA and Cos, P and Coenye, T and Fallarero, A and Zaat, SAJ and Felici, A and Ferrari, L and Azevedo, NF and Parker, AE and Goeres, DM}, title = {Interlaboratory study for the evaluation of three microtiter plate-based biofilm quantification methods.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {13779}, pmid = {34215805}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; Gentian Violet/pharmacology ; Humans ; Oxazines/pharmacology ; Sodium Hypochlorite/*pharmacology ; Staphylococcal Infections/diagnosis/microbiology ; Staphylococcus aureus/*drug effects/growth & development/pathogenicity ; Xanthenes/pharmacology ; }, abstract = {Microtiter plate methods are commonly used for biofilm assessment. However, results obtained with these methods have often been difficult to reproduce. Hence, it is important to obtain a better understanding of the repeatability and reproducibility of these methods. An interlaboratory study was performed in five different laboratories to evaluate the reproducibility and responsiveness of three methods to quantify Staphylococcus aureus biofilm formation in 96-well microtiter plates: crystal violet, resazurin, and plate counts. An inter-lab protocol was developed for the study. The protocol was separated into three steps: biofilm growth, biofilm challenge, biofilm assessment. For control experiments participants performed the growth and assessment steps only. For treatment experiments, all three steps were performed and the efficacy of sodium hypochlorite (NaOCl) in killing S. aureus biofilms was evaluated. In control experiments, on the log10-scale, the reproducibility SD (SR) was 0.44 for crystal violet, 0.53 for resazurin, and 0.92 for the plate counts. In the treatment experiments, plate counts had the best responsiveness to different levels of efficacy and also the best reproducibility with respect to responsiveness (Slope/SR = 1.02), making it the more reliable method to use in an antimicrobial efficacy test. This study showed that the microtiter plate is a versatile and easy-to-use biofilm reactor, which exhibits good repeatability and reproducibility for different types of assessment methods, as long as a suitable experimental design and statistical analysis is applied.}, } @article {pmid34215744, year = {2021}, author = {Johnston, I and Osborn, LJ and Markley, RL and McManus, EA and Kadam, A and Schultz, KB and Nagajothi, N and Ahern, PP and Brown, JM and Claesen, J}, title = {Identification of essential genes for Escherichia coli aryl polyene biosynthesis and function in biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {56}, pmid = {34215744}, issn = {2055-5008}, support = {R01 DK120679/DK/NIDDK NIH HHS/United States ; R01 AI153173/AI/NIAID NIH HHS/United States ; P01 HL147823/HL/NHLBI NIH HHS/United States ; P30 CA043703/CA/NCI NIH HHS/United States ; T32 GM088088/GM/NIGMS NIH HHS/United States ; P50 AA024333/AA/NIAAA NIH HHS/United States ; }, mesh = {*Biofilms/growth & development ; Biological Transport ; Biosynthetic Pathways ; Escherichia coli/*genetics/*metabolism ; Escherichia coli Proteins/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; *Genes, Essential ; Molecular Structure ; Mutation ; Oxidation-Reduction ; Phenotype ; Polyenes/chemistry/*metabolism ; }, abstract = {Aryl polyenes (APEs) are specialized polyunsaturated carboxylic acids that were identified in silico as the product of the most widespread family of bacterial biosynthetic gene clusters (BGCs). They are present in several Gram-negative host-associated bacteria, including multidrug-resistant human pathogens. Here, we characterize a biological function of APEs, focusing on the BGC from a uropathogenic Escherichia coli (UPEC) strain. We first perform a genetic deletion analysis to identify the essential genes required for APE biosynthesis. Next, we show that APEs function as fitness factors that increase protection from oxidative stress and contribute to biofilm formation. Together, our study highlights key steps in the APE biosynthesis pathway that can be explored as potential drug targets for complementary strategies to reduce fitness and prevent biofilm formation of multi-drug resistant pathogens.}, } @article {pmid34214645, year = {2021}, author = {Tao, J and Yan, S and Zhou, C and Liu, Q and Zhu, H and Wen, Z}, title = {Total flavonoids from Potentilla kleiniana Wight et Arn inhibits biofilm formation and virulence factors production in methicillin-resistant Staphylococcus aureus (MRSA).}, journal = {Journal of ethnopharmacology}, volume = {279}, number = {}, pages = {114383}, doi = {10.1016/j.jep.2021.114383}, pmid = {34214645}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/*growth & development ; Flavonoids/chemistry/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Potentilla/*chemistry ; Virulence Factors/genetics/*metabolism ; }, abstract = {Potentilla kleiniana Wight et Arn is a wide-spread wild plant in the mountainous areas in southern China. The whole herb has been used as a traditional herbal medicine to treat fever, arthritis, malaria, insect and snake bites, hepatitis, and traumatic injury. In vitro studies have reported the antibacterial activity use of the plant in traditional medicinal systems.

AIM OF THE STUDY: The aim of this study was to investigate the inhibitory activity of total flavonoid from Potentilla kleiniana Wight et Arn (TFP) on methicillin-resistant Staphylococcus aureus (MRSA) in planktonic state and biofilm state.

MATERIALS AND METHODS: Antibacterial activities of TFP on planktonic MRSA were determined by agar diffusion method, microtiter plate assay and time-kill curve assay. Electrical conductivity, membrane permeability, membrane potential and autoaggregation were analyzed to study TFP effects on planktonic MRSA growth. Crystal violet (CV) staining and confocal laser scanning microscopy (CLSM) were analyzed to study TFP effects on aggregation and maturation of MRSA biofilm. After TFP treatment, extracellular polymeric substances (EPS) production were examined. Morphological changes in planktonic and MRSA biofilm following TFP treatment were determined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, α-Toxin protein expression and adhesion-related gene expression were also determined.

RESULTS: The minimum inhibitory concentration (MIC) of TFP against MRSA was 20 μg/mL. The agar diffusion method and time-kill curve assay results indicated that TFP inhibited planktonic MRSA growth. TFP treatment significantly inhibited planktonic MRSA growth by inhibiting autoaggregation, α-hemolysin activity, α-Toxin protein expression, but increasing electrolyte leakage, membrane permeability and membrane potential and impacting cell structure. Moreover, TFP treatment significantly inhibited aggregation and maturation on MRSA biofilm by decreasing surface hydrophobicity, EPS production and adhesion-related gene expression.

CONCLUSION: The results of this trial provide scientific experimental data on the traditional use of Potentilla Kleiniana Wight et Arn for traumatic injury treatment and further demonstrate the potential of TFP to be developed as a novel anti-biofilm drug.}, } @article {pmid34214497, year = {2021}, author = {Hussein, H and Kishen, A}, title = {Engineered Chitosan-based Nanoparticles Modulate Macrophage-Periodontal Ligament Fibroblast Interactions in Biofilm-mediated Inflammation.}, journal = {Journal of endodontics}, volume = {47}, number = {9}, pages = {1435-1444}, doi = {10.1016/j.joen.2021.06.017}, pmid = {34214497}, issn = {1878-3554}, mesh = {Biofilms ; *Chitosan/pharmacology ; Fibroblasts ; Humans ; Inflammation ; Macrophages ; *Nanoparticles ; Periodontal Ligament ; }, abstract = {INTRODUCTION: Crosstalk between immune cells and tissue-resident cells regulates the pathophysiology and posttreatment healing of apical periodontitis. This investigation aimed to understand the influence of residual root canal biofilm on macrophage (MQ)-periodontal ligament fibroblast (PdLF) interaction and evaluate the effect of engineered chitosan-based nanoparticles (CSnp) on MQ-PdLF interactions in residual biofilm-mediated inflammation.

METHODS: Six-week-old Enterococcus faecalis biofilms in root canal models were disinfected conventionally using sodium hypochlorite alone or followed by calcium hydroxide medication or CSnp dispersed in carboxymethylated chitosan (CMCS). The effect of the treated biofilms (n = 25/group) on the inflammatory response of THP-1-differentiated MQ monoculture versus coculture with PdLF was evaluated for cell viability, MQ morphometric characterization, inflammatory mediators (nitric oxide, tumor necrosis factor alpha, interleukin [IL]-1 beta, IL-1RA, IL-6, transforming growth factor beta 1 [TGF-β1], and IL-10), and the expression of transcription factors (pSTAT1/pSTAT6)/cluster of differentiation markers (CD80/206) after 24, 48, and 72 hours of interaction. PdLF transwell migration was evaluated after 8 and 24 hours. Unstimulated cells served as the negative control, whereas untreated biofilm was the positive control.

RESULTS: Biofilm increased nitric oxide and IL-1β but suppressed IL-10, IL-1RA, and PdLF migration with significant cytotoxic effects. CSnp/CMCS reduced nitric oxide and IL-1β (P < .01) while maintaining ≥90% cell survival up to 72 hours with evident M2-like MQ phenotypic changes in coculture. CSnp/CMCS also increased the IL-1RA/IL-1β ratio and enhanced TGF-β1 production over time (P < .05, 72 hours). In coculture, CSnp/CMCS showed the highest IL-10 level at 72 hours (P < .01), reduced the pSTAT1/pSTAT6 ratio, and enhanced PdLF migration (P < .01, 24 hours).

CONCLUSIONS: CSnp/CMCS medication facilitated MQ switch toward M2 (regulatory/anti-inflammatory) phenotype and PdLF migration via paracrine signaling.}, } @article {pmid34210981, year = {2021}, author = {Shang, L and Yan, Y and Zhan, Y and Ke, X and Shao, Y and Liu, Y and Yang, H and Wang, S and Dai, S and Lu, J and Yan, N and Yang, Z and Lu, W and Liu, Z and Chen, S and Elmerich, C and Lin, M}, title = {A regulatory network involving Rpo, Gac and Rsm for nitrogen-fixing biofilm formation by Pseudomonas stutzeri.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {54}, pmid = {34210981}, issn = {2055-5008}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Gene Order ; *Gene Regulatory Networks ; *Nitrogen Fixation ; Nitrogenase/genetics/metabolism ; Pseudomonas stutzeri/*physiology ; Repetitive Sequences, Nucleic Acid ; Transcriptional Activation ; }, abstract = {Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.}, } @article {pmid34210263, year = {2021}, author = {Derakhshan, S and Navidinia, M and Haghi, F}, title = {Antibiotic susceptibility of human-associated Staphylococcus aureus and its relation to agr typing, virulence genes, and biofilm formation.}, journal = {BMC infectious diseases}, volume = {21}, number = {1}, pages = {627}, pmid = {34210263}, issn = {1471-2334}, mesh = {*Bacterial Proteins ; Bacterial Toxins/genetics ; *Biofilms ; Drug Resistance, Bacterial ; Enterotoxins/genetics ; Exfoliatins/genetics ; Female ; Hemolysin Proteins/genetics ; Humans ; Male ; Microbial Sensitivity Tests ; Phenotype ; Polymerase Chain Reaction ; Staphylococcus aureus/*genetics/*isolation & purification/*pathogenicity/*physiology ; Superantigens/genetics ; *Trans-Activators ; Virulence Factors/*genetics ; Xanthophylls ; }, abstract = {BACKGROUND AND OBJECTIVE: Carriage of virulence factors confers some evolutionary benefit to bacteria, which favors the resistant strains. We aimed to analyze whether antibiotic susceptibility of Staphylococcus aureus strains is affected by agr typing, biofilm formation ability, and virulence profiles.

METHODS: A total of 123 S. aureus clinical isolates were subjected to antimicrobial susceptibility testing by disk diffusion method, biofilm formation by microtiter plate method, as well as polymerase chain reaction screening to identify virulence genes and the accessory gene regulator (agr) types I-IV. A P value < 0.05 was considered significant.

RESULTS: The most prevalent virulence gene was staphyloxanthin crtN, followed by hemolysin genes, capsular cap8H, toxic shock toxin tst, and enterotoxin sea, respectively. Resistant isolates were more commonly found in the agr-negative group than in the agr-positive group. Isolates of agr type III were more virulent than agr I isolates. Strong biofilm producers showed more antibiotic susceptibility and carried more virulence genes than non-strong biofilm producers. Associations were found between the presence of virulence genes and susceptibility to antibiotics. Carriage of the virulence genes and agr was higher in the inpatients; while, resistance and strong biofilms were more prevalent in the outpatients.

CONCLUSION: These findings indicated the presence of several virulence factors, biofilm production capacity, agr types and resistance to antibiotics in clinical S. aureus isolates. Considering the importance of S. aureus for human medicine, an understanding of virulence and resistance relationships would help to reduce the impact of S. aureus infections.}, } @article {pmid34210218, year = {2021}, author = {Burgos-Garay, ML and Santiago, AJ and Kartforosh, L and Kotay, S and Donlan, RM}, title = {Supplemental nutrients stimulate the amplification of carbapenemase-producing Klebsiella pneumoniae (CPKP) in a sink drain in vitro biofilm reactor model.}, journal = {Biofouling}, volume = {37}, number = {5}, pages = {465-480}, doi = {10.1080/08927014.2021.1915998}, pmid = {34210218}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacterial Proteins ; Biofilms ; Humans ; *Klebsiella Infections ; *Klebsiella pneumoniae ; Nutrients ; beta-Lactamases ; }, abstract = {Liquid wastes (LW) disposed in hospital handwashing sinks may affect colonization of sink P-traps by carbapenemase-producing Klebsiella pneumoniae (CPKP), causing CPKP dispersal into the patient care environment. This study aimed to determine the effect of LW on biofilm formation and CPKP colonization in a P-Trap model (PTM). PTMs containing polymicrobial biofilms grown in autoclaved municipal tap water (ATW) supplemented with 5% dextrose in water (D5W), nutritional shake (Shake), sugar-based soft drink (Soda), or ATW were inoculated with K. pneumoniae ST258 KPC+ (ST258) or K. pneumoniae CAV1016 (CAV1016) and sampled after 7, 14, and 21 d. Biofilm bio-volume, mean thickness, and heterotrophic plate counts were significantly reduced and roughness coefficient significantly increased by Soda compared with D5W, Shake, or ATW. CPKP were significantly reduced by Soda but significantly amplified by D5W (ST258; CAV1016, 7 d) and Shake (ST258) suggesting that reducing LW disposal in sinks may reduce CPKP dispersal into patient care environments.}, } @article {pmid34210036, year = {2021}, author = {Matilla-Cuenca, L and Toledo-Arana, A and Valle, J}, title = {Anti-Biofilm Molecules Targeting Functional Amyloids.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34210036}, issn = {2079-6382}, support = {RTI2018-096011-B-I00//Spanish Ministry of Science, Innovation and Universities/ ; }, abstract = {The choice of an effective therapeutic strategy in the treatment of biofilm-related infections is a significant issue. Amyloids, which have been historically related to human diseases, are now considered to be prevailing structural components of the biofilm matrix in a wide range of bacteria. This assumption creates the potential for an exciting research area, in which functional amyloids are considered to be attractive targets for drug development to dissemble biofilm structures. The present review describes the best-characterized bacterial functional amyloids and focuses on anti-biofilm agents that target intrinsic and facultative amyloids. This study provides a better understanding of the different modes of actions of the anti-amyloid molecules to inhibit biofilm formation. This information can be further exploited to improve the therapeutic strategies to combat biofilm-related infections.}, } @article {pmid34209737, year = {2021}, author = {Steixner, SJM and Spiegel, C and Dammerer, D and Wurm, A and Nogler, M and Coraça-Huber, DC}, title = {Influence of Nutrient Media Compared to Human Synovial Fluid on the Antibiotic Susceptibility and Biofilm Gene Expression of Coagulase-Negative Staphylococci In Vitro.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34209737}, issn = {2079-6382}, abstract = {Bacterial antibiotic resistance and biofilm formation are mechanisms usually involved in the pathogeny of implant-related infections. Worldwide, antibiotic susceptibility tests are usually carried out using nutrient-rich media. Clinical routine laboratories and even research centers use for example EUCAST or CLSI for guidelines. In this study, we investigated the effect of different nutrient media on the antibiotic susceptibility and icaADBC gene expression of bacteria in biofilm. As media, Müller-Hinton Bouillon (MHB), Tryptic Soy Broth (TSB) and human synovial fluid (SF) diluted 1:4 in phosphate buffered saline (PBS), each also supplemented with 1% glucose, were used. The influence of different nutrient media on the antibiotic susceptibility of coagulase-negative staphylococci (CoNS) was evaluated by counting of colony-forming units (CFU) and by checking the metabolic activity of the bacteria. We used reverse transcriptase and real-time qPCR to investigate the influence of nutrient media on the biofilm gene expression. We used two-way analysis of variance (ANOVA). p < 0.05 was considered to be statistically significant. Significant differences in growth and antibiotic susceptibility were detected in all strains tested among the different media used. The nutrient media showed influence on the cell viability of all bacteria after antibiotic treatment. IcaADBC gene expression was significantly influenced by glucose and all nutrient media. The results highlight the influence of glucose on the antibiotic susceptibility, growth and gene expression of all strains tested. For all strains, a significant difference in bacterial recovery, viability and gene expression were found when compared to biofilm grown in SF.}, } @article {pmid34209470, year = {2021}, author = {Genovese, C and D'Angeli, F and Bellia, F and Distefano, A and Spampinato, M and Attanasio, F and Nicolosi, D and Di Salvatore, V and Tempera, G and Lo Furno, D and Mannino, G and Milardo, F and Li Volti, G}, title = {Correction: Genovese et al. In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains. Antibiotics 2021, 10, 428.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34209470}, issn = {2079-6382}, abstract = {The authors would like to make the following corrections to the published paper [...].}, } @article {pmid34209453, year = {2021}, author = {Lordello, VB and Meneguin, AB and de Annunzio, SR and Taranto, MP and Chorilli, M and Fontana, CR and Cavallini, DCU}, title = {Orodispersible Film Loaded with Enterococcus faecium CRL183 Presents Anti-Candida albicans Biofilm Activity In Vitro.}, journal = {Pharmaceutics}, volume = {13}, number = {7}, pages = {}, pmid = {34209453}, issn = {1999-4923}, support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; # 2018/23015-7 and # 2018/09088-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {BACKGROUND: Probiotic bacteria have been emerging as a trustworthy choice for the prevention and treatment of Candida spp. infections. This study aimed to develop and characterize an orodispersible film (ODF) for delivering the potentially probiotic Enterococcus faecium CRL 183 into the oral cavity, evaluating its in vitro antifungal activity against Candida albicans.

METHODS AND RESULTS: The ODF was composed by carboxymethylcellulose, gelatin, and potato starch, and its physical, chemical, and mechanical properties were studied. The probiotic resistance and viability during processing and storage were evaluated as well as its in vitro antifungal activity against C. albicans. The ODFs were thin, resistant, and flexible, with neutral pH and microbiologically safe. The probiotic resisted the ODF obtaining process, demonstrating high viability (>9 log10 CFU·g[-1]), up to 90 days of storage at room temperature. The Probiotic Film promoted 68.9% of reduction in fungal early biofilm and 91.2% in its mature biofilm compared to the group stimulated with the control film. Those results were confirmed through SEM images.

CONCLUSION: The probiotic ODF developed is a promising strategy to prevent oral candidiasis, since it permits the local probiotic delivery, which in turn was able to reduce C. albicans biofilm formation.}, } @article {pmid34208591, year = {2021}, author = {Ansari, MA and Kalam, A and Al-Sehemi, AG and Alomary, MN and AlYahya, S and Aziz, MK and Srivastava, S and Alghamdi, S and Akhtar, S and Almalki, HD and Adil, SF and Khan, M and Hatshan, MR}, title = {Counteraction of Biofilm Formation and Antimicrobial Potential of Terminalia catappa Functionalized Silver Nanoparticles against Candida albicans and Multidrug-Resistant Gram-Negative and Gram-Positive Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {34208591}, issn = {2079-6382}, abstract = {Biofilms not only protect bacteria and Candida species from antibiotics, but they also promote the emergence of drug-resistant strains, making eradication more challenging. As a result, novel antimicrobial agents to counteract biofilm formation are desperately needed. In this study, Terminalia catappa leaf extract (TCE) was used to optimize the TCE-capped silver nanoparticles (TCE-AgNPs) via a one-pot single-step method. Varied concentrations of TCE have yielded different sized AgNPs. The physico-chemical characterization of TCE-AgNPs using UV-Vis, SEM, TEM, FTIR, and Raman spectroscopy have confirmed the formation of nanostructures, their shape and size and plausible role of TCE bio-active compounds, most likely involved in the synthesis as well as stabilization of NPs, respectively. TCE-AgNPs have been tested for antibiofilm and antimicrobial activity against multidrug-resistant Pseudomonas aeruginosa (MDR-PA), methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans using various microbiological protocols. TCE-Ag-NPs-3 significantly inhibits biofilm formation of MDR-PA, MRSA, and C. albicans by 73.7, 69.56, and 63.63%, respectively, at a concentration of 7.8 µg/mL, as determined by crystal violet microtiter assay. Furthermore, SEM micrograph shows that TCE-AgNPs significantly inhibit the colonization and adherence of biofilm forming cells; individual cells with loss of cell wall and membrane integrity were also observed, suggesting that the biofilm architecture and EPS matrix were severely damaged. Moreover, TEM and SEM images showed that TCE-AgNPs brutally damaged the cell wall and membranes of MDR-PA, MRSA, and C. albicans. Additionally, extreme ultrastructural changes such as deformation, disintegration, and separation of cell wall and membrane from the cells, have also been observed, indicating significant loss of membrane and cell wall integrity, which eventually led to cell death. Overall, the research revealed a simple, environmentally friendly, and low-cost method for producing colloidal TCE-AgNPs with promising applications in advanced clinical settings against broad-spectrum biofilm-forming antibiotic-resistant bacteria and candida strains.}, } @article {pmid34208588, year = {2021}, author = {Chen, X and Daliri, EB and Tyagi, A and Oh, DH}, title = {Cariogenic Biofilm: Pathology-Related Phenotypes and Targeted Therapy.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34208588}, issn = {2076-2607}, support = {22A20153713433//the Brain Korea (BK) 21 Plus Project/ ; }, abstract = {The initiation and development of cariogenic (that is, caries-related) biofilms are the result of the disruption of homeostasis in the oral microenvironment. There is a daily accumulation of dental biofilm on the surface of teeth and its matrix of extracellular polymers supports the host in its defense against invading microbes, thus helping to achieve oral microbial homeostasis. However, the homeostasis can be broken down under certain circumstances such as during long-term exposure to a low pH environment which results in the dominance of acidogenic and acid-tolerating species in the dental biofilm and, thus, triggers the shift of harmless biofilm to an acidic one. This work aims to explore microbial diversity and the quorum sensing of dental biofilm and their important contributions to oral health and disease. The complex and multispecies ecosystems of the cariogenic biofilm pose significant challenges for the modulation of the oral microenvironment. Promising treatment strategies are those that target cariogenic niches with high specificity without disrupting the balance of the surrounding oral microbiota. Here, we summarized the recent advances in modulating cariogenic biofilm and/or controlling its pathogenic traits.}, } @article {pmid34208134, year = {2021}, author = {Ali, IAA and Matinlinna, JP and Lévesque, CM and Neelakantan, P}, title = {Trans-Cinnamaldehyde Attenuates Enterococcus faecalis Virulence and Inhibits Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {34208134}, issn = {2079-6382}, support = {Seed Fund for Basic Research 201811159064//University Research Committee, University of Hong Kong/ ; }, abstract = {Enterococcus faecalis as an important nosocomial pathogen is critically implicated in the pathogenesis of endocarditis, urinary tract, and persistent root canal infections. Its major virulence attributes (biofilm formation, production of proteases, and hemolytic toxins) enable it to cause extensive host tissue damage. With the alarming increase in enterococcal resistance to antibiotics, novel therapeutics are required to inhibit E. faecalis biofilm formation and virulence. Trans-cinnamaldehyde (TC), the main phytochemical in cinnamon essential oils, has demonstrated promising activity against a wide range of pathogens. Here, we comprehensively investigated the effect of TC on planktonic growth, biofilm formation, proteolytic and hemolytic activities, as well as gene regulation in E. faecalis. Our findings revealed that sub-inhibitory concentrations of TC reduced biofilm formation, biofilm exopolysaccharides, as well as its proteolytic and hemolytic activities. Mechanistic studies revealed significant downregulation of the quorum sensing fsr locus and downstream gelE, which are major virulence regulators in E. faecalis. Taken together, our study highlights the potential of TC to inhibit E. faecalis biofilm formation and its virulence.}, } @article {pmid34207425, year = {2021}, author = {Arweiler, NB and Rahmel, V and Alhamwe, BA and Alhamdan, F and Zemlin, M and Boutin, S and Dalpke, A and Renz, H}, title = {Dental Biofilm and Saliva Microbiome and Its Interplay with Pediatric Allergies.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34207425}, issn = {2076-2607}, abstract = {Little is known about the interplay and contribution of oral microorganisms to allergic diseases, especially in children. The aim of the clinical study was to associate saliva and dental biofilm microbiome with allergic disease, in particular with allergic asthma. In a single-center study, allergic/asthmatic children (n = 15; AA-Chd; age 10.7 ± 2.9), atopic/allergic children (n = 16; AT/AL-Chd; 11.3 ± 2.9), and healthy controls (n = 15; CON-Chd; age 9.9 ± 2.2) were recruited. After removing adhering biofilms from teeth and collecting saliva, microbiome was analyzed by using a 16s-rRNA gene-based next-generation sequencing in these two mediums. Microbiome structure differed significantly between saliva and dental biofilms (β-diversity). Within the groups, the dental biofilm microbiome of AA-Chd and AT/AL-Chd showed a similar microbial fingerprint characterized by only a small number of taxa that were enriched or depleted (4) compared to the CON-Chd, while both diseased groups showed a stronger microbial shift compared to CON-Chd, revealing 14 taxa in AA-Chd and 15 taxa in AT/AL-Chd that were different. This could be the first note to the contribution of dental biofilm and its metabolic activity to allergic health or disease.}, } @article {pmid34206833, year = {2021}, author = {Panebianco, F and Rubiola, S and Chiesa, F and Civera, T and Di Ciccio, PA}, title = {Effect of Gaseous Ozone on Listeria monocytogenes Planktonic Cells and Biofilm: An In Vitro Study.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34206833}, issn = {2304-8158}, support = {D24I19000980002//European Regional Development Fund/ ; }, abstract = {Among food-borne pathogens, Listeria monocytogenes continues to pose concerns to food business operators due to its capacity to form biofilm in processing environments. Ozone may be an eco-friendly technology to control microbial contaminations, but data concerning its effect on Listeria monocytogenes biofilm are still limited. In this study, the effect of gaseous ozone at 50 ppm on planktonic cells and biofilm of reference and food-related Listeria monocytogenes strains was evaluated. Ozone caused a reduction in microbial loads of 3.7 ± 0.4 and 3.9 ± 0.4 Log10 CFU/mL after 10 and 30 min, respectively. A complete inactivation of planktonic cells after 6 h of treatment was observed. Biofilm inhibition and eradication treatments (50 ppm, 6 h) resulted in a significant decrease of the biofilm biomass for 59% of the strains tested, whilst a slight dampening of live cell loads in the biofilm state was observed. In conclusion, gaseous ozone is not sufficient to completely counteract Listeria monocytogenes biofilm, but it may be useful as an additional tool to contrast Listeria monocytogenes free-living cells and to improve the existing sanitization procedures in food processing environments.}, } @article {pmid34206680, year = {2021}, author = {Pompilio, A and Scribano, D and Sarshar, M and Di Bonaventura, G and Palamara, AT and Ambrosi, C}, title = {Gram-Negative Bacteria Holding Together in a Biofilm: The Acinetobacter baumannii Way.}, journal = {Microorganisms}, volume = {9}, number = {7}, pages = {}, pmid = {34206680}, issn = {2076-2607}, support = {SG-2018-12365432//Ministero della Salute/ ; none//Dani di Giò Foundation/ ; AGRINTO//Ministero della Difesa/ ; ARS01_00597//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; }, abstract = {Bacterial biofilms are a serious public-health problem worldwide. In recent years, the rates of antibiotic-resistant Gram-negative bacteria associated with biofilm-forming activity have increased worrisomely, particularly among healthcare-associated pathogens. Acinetobacter baumannii is a critically opportunistic pathogen, due to the high rates of antibiotic resistant strains causing healthcare-acquired infections (HAIs). The clinical isolates of A. baumannii can form biofilms on both biotic and abiotic surfaces; hospital settings and medical devices are the ideal environments for A. baumannii biofilms, thereby representing the main source of patient infections. However, the paucity of therapeutic options poses major concerns for human health infections caused by A. baumannii strains. The increasing number of multidrug-resistant A. baumannii biofilm-forming isolates in association with the limited number of biofilm-eradicating treatments intensify the need for effective antibiofilm approaches. This review discusses the mechanisms used by this opportunistic pathogen to form biofilms, describes their clinical impact, and summarizes the current and emerging treatment options available, both to prevent their formation and to disrupt preformed A. baumannii biofilms.}, } @article {pmid34205984, year = {2021}, author = {Erensoy, A and Çek, N}, title = {Investigation of Polymer Biofilm Formation on Titanium-Based Anode Surface in Microbial Fuel Cells with Poplar Substrate.}, journal = {Polymers}, volume = {13}, number = {11}, pages = {}, pmid = {34205984}, issn = {2073-4360}, abstract = {Microbial fuel cells (MFCs) have attracted attention by directly converting the bioelectrochemical energy possessed by the organic materials that make up the biomass into electrical energy. In this study, the relationship between the biofilm formed on the titanium-based anode electrode surface, and the chemical composition of the substrate, the energy source of MFC, was investigated. For this, MFCs were made by using poplar wood shavings rich in organic material as the substrate, titanium-based material as the anode electrode, and natural soil as bacterial habitat. Three types of MFCs containing 1%, 10%, and 20% poplar wood shavings by weight were made and named P1-MFC, P2-MFC, and P3-MFC, respectively. According to electrochemical analysis, P3-MFC provided the highest open circuit voltage with 490 mV value, and the highest power density with 5.11 mW/m[2] value compared to other MFCs. According to optical microscopy examinations, there were Bacillus and Coccus species of bacteria in the soil structure, and these bacteria also existed around the fiber of poplar wood shavings in MFCs. Scanning electron microscopy (SEM), energy-dispersive spectrum (EDS), and Fourier transform infrared spectroscopy (FTIR) analysis showed that MFCs formed biofilm in the titanium-based anode, and the chemical composition of this biofilm with poplar tree was similar. As a result, due to the catalysis reactions of bacteria, the titanium-based anode electrode surface was coated with polymer biofilm released from poplar wood shavings.}, } @article {pmid34205417, year = {2021}, author = {Abedon, ST and Danis-Wlodarczyk, KM and Wozniak, DJ and Sullivan, MB}, title = {Improving Phage-Biofilm In Vitro Experimentation.}, journal = {Viruses}, volume = {13}, number = {6}, pages = {}, pmid = {34205417}, issn = {1999-4915}, support = {R01 AI169865/AI/NIAID NIH HHS/United States ; R21 AI156304/AI/NIAID NIH HHS/United States ; R01AI43916//U.S. Public Health Service/ ; R01AI34895//U.S. Public Health Service/ ; }, mesh = {Bacteria/*virology ; Bacteriolysis ; Bacteriophages/*growth & development ; Biofilms/*growth & development ; In Vitro Techniques/methods ; Microbial Interactions ; }, abstract = {Bacteriophages or phages, the viruses of bacteria, are abundant components of most ecosystems, including those where bacteria predominantly occupy biofilm niches. Understanding the phage impact on bacterial biofilms therefore can be crucial toward understanding both phage and bacterial ecology. Here, we take a critical look at the study of bacteriophage interactions with bacterial biofilms as carried out in vitro, since these studies serve as bases of our ecological and therapeutic understanding of phage impacts on biofilms. We suggest that phage-biofilm in vitro experiments often may be improved in terms of both design and interpretation. Specific issues discussed include (a) not distinguishing control of new biofilm growth from removal of existing biofilm, (b) inadequate descriptions of phage titers, (c) artificially small overlying fluid volumes, (d) limited explorations of treatment dosing and duration, (e) only end-point rather than kinetic analyses, (f) importance of distinguishing phage enzymatic from phage bacteriolytic anti-biofilm activities, (g) limitations of biofilm biomass determinations, (h) free-phage interference with viable-count determinations, and (i) importance of experimental conditions. Toward bettering understanding of the ecology of bacteriophage-biofilm interactions, and of phage-mediated biofilm disruption, we discuss here these various issues as well as provide tips toward improving experiments and their reporting.}, } @article {pmid34205399, year = {2021}, author = {Karahutová, L and Mandelík, R and Bujňáková, D}, title = {Antibiotic Resistant and Biofilm-Associated Escherichia coli Isolates from Diarrheic and Healthy Dogs.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34205399}, issn = {2076-2607}, support = {2/0010/21//Vedecká Grantová Agentúra MŠVVaŠ SR a SAV/ ; CA18217//Cost Action/ ; }, abstract = {Bacteria isolated from companion animals are attracting concerns in a view of public health including antimicrobial resistance and biofilm development, both contributing to difficult-to-treat infections. The purpose of this study was to evaluate the minimum inhibitory concentrations (MIC) of 18 antibiotics in Escherichia coli isolated from two groups of dogs (healthy and diarrheic). Isolates were classified into phylogroups, examined for the presence of resistance genes and biofilm-formation capacity. In healthy dogs, phylogenetic analysis showed that 47.37% and 34.22% of E. coli isolates belonged to commensal groups (A; B1) in contrast to diarrheic dogs; 42.2% of isolates were identified as the B2 phylogroup, and these E. coli bacteria formed a stronger biofilm. The results of healthy dogs showed higher MIC levels for tetracycline (32 mg/L), ampicillin (64 mg/L), ciprofloxacin (8 mg/L) and trimethoprim-sulphonamide (8 mg/L) compared to clinical breakpoints. The most detected gene encoding plasmid-mediated resistance to quinolones in the healthy group was qnrB, and in dogs with diarrhea, qnrS. The resistance genes were more frequently detected in healthy dogs. The presence of the integron int1 and the transposon tn3 increases the possibility of transfer of many different cassette-associated antibiotic-resistance genes. These results suggest that dogs could be a potential reservoir of resistance genes.}, } @article {pmid34204135, year = {2021}, author = {Rossi, F and Cattò, C and Mugnai, G and Villa, F and Forlani, F}, title = {Effects of the Quinone Oxidoreductase WrbA on Escherichia coli Biofilm Formation and Oxidative Stress.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {34204135}, issn = {2076-3921}, support = {2017-0977//Fondazione Cariplo/ ; }, abstract = {The effects of natural compounds on biofilm formation have been extensively studied, with the goal of identifying biofilm formation antagonists at sub-lethal concentrations. Salicylic and cinnamic acids are some examples of these compounds that interact with the quinone oxidoreductase WrbA, a potential biofilm modulator and an antibiofilm compound biomarker. However, WrbA's role in biofilm development is still poorly understood. To investigate the key roles of WrbA in biofilm maturation and oxidative stress, Escherichia coli wild-type and ∆wrbA mutant strains were used. Furthermore, we reported the functional validation of WrbA as a molecular target of salicylic and cinnamic acids. The lack of WrbA did not impair planktonic growth, but rather affected the biofilm formation through a mechanism that depends on reactive oxygen species (ROS). The loss of WrbA function resulted in an ROS-sensitive phenotype that showed reductions in biofilm-dwelling cells, biofilm thickness, matrix polysaccharide content, and H2O2 tolerance. Endogenous oxidative events in the mutant strain generated a stressful condition to which the bacterium responded by increasing the catalase activity to compensate for the lack of WrbA. Cinnamic and salicylic acids inhibited the quinone oxidoreductase activity of purified recombinant WrbA. The effects of these antibiofilm molecules on WrbA function was proven for the first time.}, } @article {pmid34203245, year = {2021}, author = {Siddique, A and Azim, S and Ali, A and Andleeb, S and Ahsan, A and Imran, M and Rahman, A}, title = {Antimicrobial Resistance Profiling of Biofilm Forming Non Typhoidal Salmonella enterica Isolates from Poultry and Its Associated Food Products from Pakistan.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34203245}, issn = {2079-6382}, abstract = {Salmonellosis caused by non-typhoidal Salmonella enterica from poultry products is a major public health concern worldwide. This study aimed at estimating the pathogenicity and antimicrobial resistance in S. enterica isolates obtained from poultry birds and their food products from different areas of Pakistan. In total, 95/370 (25.67%) samples from poultry droppings, organs, eggs, and meat were positive for Salmonella. The isolates were further identified through multiplex PCR (mPCR) as Salmonella Typhimurium 14 (14.7%), Salmonella Enteritidis 12 (12.6%), and other Salmonella spp. 69 (72.6%). The phenotypic virulence properties of 95 Salmonella isolates exhibited swimming and/or swarming motility 95 (100%), DNA degrading activity 93 (97.8%), hemolytic activity 92 (96.8%), lipase activity 87 (91.6%), and protease activity 86 (90.5%). The sopE virulence gene known for conferring zoonotic potential was detected in S. Typhimurium (92.8%), S. Enteritidis (100%), and other Salmonella spp. (69.5%). The isolates were further tested against 23 antibiotics (from 10 different antimicrobial groups) and were found resistant against fifteen to twenty-one antibiotics. All isolates showed multiple drug resistance and were found to exhibit a high multiple antibiotic-resistant (MAR) index of 0.62 to 0.91. The strong biofilm formation at 37 °C reflected their potential adherence to intestinal surfaces. There was a significant correlation between antimicrobial resistance and the biofilm formation potential of isolates. The resistance determinant genes found among the isolated strains were blaTEM-1 (59.3%), blaOxA-1 (18%), blaPSE-1 (9.5%), blaCMY-2 (43%), and ampC (8.3%). The detection of zoonotic potential MDR Salmonella in poultry and its associated food products carrying cephalosporin and quinolone resistance genes presents a major threat to the poultry industry and public health.}, } @article {pmid34203050, year = {2021}, author = {Jantorn, P and Heemmamad, H and Soimala, T and Indoung, S and Saising, J and Chokpaisarn, J and Wanna, W and Tipmanee, V and Saeloh, D}, title = {Antibiotic Resistance Profile and Biofilm Production of Staphylococcus pseudintermedius Isolated from Dogs in Thailand.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {6}, pages = {}, pmid = {34203050}, issn = {1424-8247}, support = {MET6302171S//Prince of Songkla University/ ; }, abstract = {Staphylococcus pseudintermedius is a zoonotic pathogen that can cause life-threatening infections in animals and humans. The study of methicillin-resistant S. pseudintermedius (MRSP) and its ability to produce biofilms is important to select the most suitable treatment. The prevalence and characteristics of S. pseudintermedius isolated from dogs admitted at the Veterinary Teaching Hospital, Prince of Songkla University, Thailand were assessed. Results showed that 28.30% (15/53) of the isolates were MRSP. Amplification of the mecA gene was observed in 93.33% (14/15) MRSP. Methicillin-resistant strains revealed co-resistant patterns against other antibiotics, including chloramphenicol, clindamycin, tetracycline, clarithromycin, ciprofloxacin, and trimethoprim. In this study, all bacterial isolates produced biofilms, while 90.55% of S. pseudintermedius isolates were strong or moderate biofilm producers. Most (45-60%) of the resistant strains were strong biofilm producers, while the correlation between biofilm production and antibiotic resistance was not statistically significant. This is the first study in southern Thailand to investigate the drug-resistant profile of S. pseudintermedius and its ability to form biofilm. The results will contribute to a better understanding of the emergence and prevalence of antimicrobial resistance in S. pseudintermedius.}, } @article {pmid34203028, year = {2021}, author = {Roy, R and You, RI and Chang, CH and Yang, CY and Lin, NT}, title = {Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34203028}, issn = {2076-2607}, support = {MOST 108-2320-B-320-008-//Ministry of Sciences and Technology/ ; }, abstract = {Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.}, } @article {pmid34202806, year = {2021}, author = {Lange, A and Grzenia, A and Wierzbicki, M and Strojny-Cieslak, B and Kalińska, A and Gołębiewski, M and Radzikowski, D and Sawosz, E and Jaworski, S}, title = {Silver and Copper Nanoparticles Inhibit Biofilm Formation by Mastitis Pathogens.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {7}, pages = {}, pmid = {34202806}, issn = {2076-2615}, support = {LID-ER/6/0070/L-7/15/NCBR/2016//National Center for Research and Development/ ; }, abstract = {Bovine mastitis is a common bovine disease, frequently affecting whole herds of cattle. It is often caused by resistant microbes that can create a biofilm structure. The rapidly developing scientific discipline known as nanobiotechnology may help treat this illness, thanks to the extraordinary properties of nanoparticles. The aim of the study was to investigate the inhibition of biofilms created by mastitis pathogens after treatment with silver and copper nanoparticles, both individually and in combination. We defined the physicochemical properties and minimal inhibitory concentration of the nanoparticles and observed their interaction with the cell membrane, as well as the extent of biofilm reduction. The results show that the silver-copper complex was the most active of all nanomaterials tested (biofilm was reduced by nearly 100% at a concentration of 200 ppm for each microorganism species tested). However, silver nanoparticles were also effective individually (biofilm was also reduced by nearly 100% at a concentration of 200 ppm, but at concentrations of 50 and 100 ppm, the extent of reduction was lower than for the complex). Nanoparticles can be used in new alternative therapies to treat bovine mastitis.}, } @article {pmid34202773, year = {2021}, author = {Orlandi, VT and Martegani, E and Bolognese, F and Trivellin, N and Garzotto, F and Caruso, E}, title = {Photoinactivation of Pseudomonas aeruginosa Biofilm by Dicationic Diaryl-Porphyrin.}, journal = {International journal of molecular sciences}, volume = {22}, number = {13}, pages = {}, pmid = {34202773}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/*radiation effects ; Cations ; Dose-Response Relationship, Drug ; Humans ; *Light ; Molecular Structure ; Photochemotherapy ; Photosensitizing Agents/chemistry/pharmacology ; Porphyrins/chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*growth & development/*radiation effects ; }, abstract = {In recent years, antimicrobial photodynamic therapy (aPDT) has received increasing attention as a promising tool aimed at both treating microbial infections and sanitizing environments. Since biofilm formation on biological and inert surfaces makes difficult the eradication of bacterial communities, further studies are needed to investigate such tricky issue. In this work, a panel of 13 diaryl-porphyrins (neutral, mono- and di-cationic) was taken in consideration to photoinactivate Pseudomonas aeruginosa. Among cationic photosensitizers (PSs) able to efficiently bind cells, in this study two dicationic showed to be intrinsically toxic and were ruled out by further investigations. In particular, the dicationic porphyrin (P11) that was not toxic, showed a better photoinactivation rate than monocationic in suspended cells. Furthermore, it was very efficient in inhibiting the biofilms produced by the model microorganism Pseudomonas aeruginosa PAO1 and by clinical strains derived from urinary tract infection and cystic fibrosis patients. Since P. aeruginosa represents a target very difficult to inactivate, this study confirms the potential of dicationic diaryl-porphyrins as photo-activated antimicrobials in different applicative fields, from clinical to environmental ones.}, } @article {pmid34202389, year = {2021}, author = {Pintado, A and Pérez-Martínez, I and Aragón, IM and Gutiérrez-Barranquero, JA and de Vicente, A and Cazorla, FM and Ramos, C}, title = {The Rhizobacterium Pseudomonas alcaligenes AVO110 Induces the Expression of Biofilm-Related Genes in Response to Rosellinia necatrix Exudates.}, journal = {Microorganisms}, volume = {9}, number = {7}, pages = {}, pmid = {34202389}, issn = {2076-2607}, support = {AGL2017-83368-C2-1-R//Ministerio de Ciencia, Innovación y Universidades/ ; AGL2017-83368-C2-1-R//European Regional Development Fund/ ; UMA18-FEDERJA-046//Programa Operativo FEDER Andalucía 2014-2020/ ; }, abstract = {The rhizobacterium Pseudomonas alcaligenes AVO110 exhibits antagonism toward the phytopathogenic fungus Rosellinia necatrix. This strain efficiently colonizes R. necatrix hyphae and is able to feed on their exudates. Here, we report the complete genome sequence of P. alcaligenes AVO110. The phylogeny of all available P. alcaligenes genomes separates environmental isolates, including AVO110, from those obtained from infected human blood and oyster tissues, which cluster together with Pseudomonas otitidis. Core and pan-genome analyses showed that P. alcaligenes strains encode highly heterogenic gene pools, with the AVO110 genome encoding the largest and most exclusive variable region (~1.6 Mb, 1795 genes). The AVO110 singletons include a wide repertoire of genes related to biofilm formation, several of which are transcriptionally modulated by R. necatrix exudates. One of these genes (cmpA) encodes a GGDEF/EAL domain protein specific to Pseudomonas spp. strains isolated primarily from the rhizosphere of diverse plants, but also from soil and water samples. We also show that CmpA has a role in biofilm formation and that the integrity of its EAL domain is involved in this function. This study contributes to a better understanding of the niche-specific adaptations and lifestyles of P. alcaligenes, including the mycophagous behavior of strain AVO110.}, } @article {pmid34202115, year = {2021}, author = {Czaplicka, N and Mania, S and Konopacka-Łyskawa, D}, title = {Influence of Rhamnolipids and Ionic Cross-Linking Conditions on the Mechanical Properties of Alginate Hydrogels as a Model Bacterial Biofilm.}, journal = {International journal of molecular sciences}, volume = {22}, number = {13}, pages = {}, pmid = {34202115}, issn = {1422-0067}, mesh = {Alginates/*chemistry ; Algorithms ; Bacteria/*growth & development ; Biofilms/*growth & development ; Glycolipids/*chemistry ; Hydrogels/*chemistry ; Ionic Liquids/*chemistry ; Models, Theoretical ; }, abstract = {The literature indicates the existence of a relationship between rhamnolipids and bacterial biofilm, as well as the ability of selected bacteria to produce rhamnolipids and alginate. However, the influence of biosurfactant molecules on the mechanical properties of biofilms are still not fully understood. The aim of this research is to determine the effect of rhamnolipids concentration, CaCl2 concentration, and ionic cross-linking time on the mechanical properties of alginate hydrogels using a Box-Behnken design. The mechanical properties of cross-linked alginate hydrogels were characterized using a universal testing machine. It was assumed that the addition of rhamnolipids mainly affects the compression load, and the value of this parameter is lower for hydrogels produced with biosurfactant concentration below CMC than for hydrogels obtained in pure water. In contrast, the addition of rhamnolipids in an amount exceeding CMC causes an increase in compression load. In bacterial biofilms, the presence of rhamnolipid molecules does not exceed the CMC value, which may confirm the influence of this biosurfactant on the formation of the biofilm structure. Moreover, rhamnolipids interact with the hydrophobic part of the alginate copolymer chains, and then the hydrophilic groups of adsorbed biosurfactant molecules create additional calcium ion trapping sites.}, } @article {pmid34201530, year = {2021}, author = {Pérez-Laguna, V and García-Luque, I and Ballesta, S and Rezusta, A and Gilaberte, Y}, title = {Photodynamic Therapy Combined with Antibiotics or Antifungals against Microorganisms That Cause Skin and Soft Tissue Infections: A Planktonic and Biofilm Approach to Overcome Resistances.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {7}, pages = {}, pmid = {34201530}, issn = {1424-8247}, abstract = {The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult.}, } @article {pmid34201471, year = {2021}, author = {Okba, MM and El-Shiekh, RA and Abu-Elghait, M and Sobeh, M and Ashour, RMS}, title = {HPLC-PDA-ESI-MS/MS Profiling and Anti-Biofilm Potential of Eucalyptussideroxylon Flowers.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {7}, pages = {}, pmid = {34201471}, issn = {2079-6382}, abstract = {The development of multidrug-resistant bacterial strains is a worldwide emerging problem that needs a global solution. Exploring new natural antibiofilm agents is one of the most important alternative therapies in combating bacterial infections. This study aimed at testing the antimicrobial potential of Eucalyptus sideroxylon flowers extract (ESFE) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans prior to testing the antibiofilm activity against S. aureus, P. aeruginosa and C. albicans. ESFE demonstrated antimicrobial activity and promising inhibition activity against methicillin-resistant S. aureus (MRSA) biofilm formation up to 95.9% (p < 0.05) at a concentration of 0.05 mg/mL and eradicated C. albicans biofilm formation up to 71.2% (p < 0.05) at a concentration of 0.7 mg/mL. LC-MS analysis allowed the tentative identification of eighty-three secondary metabolites: 21 phloroglucinol, 18 terpenes, 16 flavonoids, 7 oleuropeic acid derivatives, 7 ellagic acid derivatives, 6 gallic acid derivatives, 3 phenolic acids, 3 fatty acids and 2 miscellaneous. In conclusion, E. sideroxylon is a rich source of effective constituents that promote its valorization as a promising candidate in the management of multidrug-resistant bacterial infections.}, } @article {pmid34201389, year = {2021}, author = {Kim, J and Kim, S and Lee, K and Kim, RH and Hwang, KT}, title = {Antibacterial Photodynamic Inactivation of Fagopyrin F from Tartary Buckwheat (Fagopyrum tataricum) Flower against Streptococcus mutans and Its Biofilm.}, journal = {International journal of molecular sciences}, volume = {22}, number = {12}, pages = {}, pmid = {34201389}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Fagopyrum/*chemistry ; Flowers/*chemistry ; Light ; Photochemotherapy ; Photosensitizing Agents/*pharmacology ; Plant Extracts/*pharmacology ; Quinones/*pharmacology ; Streptococcus mutans/drug effects/*growth & development ; }, abstract = {The objective of this study was to determine reactive oxygen species (ROS) produced by fagopyrin F-rich fraction (FFF) separated from Tartary buckwheat flower extract exposed to lights and to investigate its antibacterial photodynamic inactivation (PDI) against Streptococcus mutans and its biofilm. ROS producing mechanisms involving FFF with light exposure were determined using a spectrophotometer and a fluorometer. S. mutans and its biofilm inactivation after PDI treatment of FFF using blue light (BL; 450 nm) were determined by plate count method and crystal violet assay, respectively. The biofilm destruction by ROS produced from FFF after exposure to BL was visualized using confocal laser scanning microscopy (CLSM) and field emission scanning electron microscope (FE-SEM). BL among 3 light sources produced type 1 ROS the most when applying FFF as a photosensitizer. FFF exposed to BL (5 and 10 J/cm[2]) significantly more inhibited S. mutans viability and biofilm formation than FFF without the light exposure (p < 0.05). In the PDI of FFF exposed to BL (10 J/cm[2]), an apparent destruction of S. mutans and its biofilm were observed by the CLSM and FE-SEM. Antibacterial PDI effect of FFF was determined for the first time in this study.}, } @article {pmid34201223, year = {2021}, author = {Celiksoy, V and Moses, RL and Sloan, AJ and Moseley, R and Heard, CM}, title = {Synergistic In Vitro Antimicrobial Activity of Pomegranate Rind Extract and Zinc (II) against Micrococcus luteus under Planktonic and Biofilm Conditions.}, journal = {Pharmaceutics}, volume = {13}, number = {6}, pages = {}, pmid = {34201223}, issn = {1999-4923}, abstract = {Infectious diseases caused by microbial biofilms are a major clinical problem, and new antimicrobial agents that can inhibit biofilm formation and eradicate pre-formed biofilms are urgently needed. Pomegranate extracts are a well-established folkloric medicine and have been used in the treatment of infectious diseases since ancient times, whilst the addition of metal ions, including zinc (II), has enhanced the antimicrobial activity of pomegranate. Micrococcus luteus is generally a non-pathogenic skin commensal bacterium, although it can act as an opportunistic pathogen and cause serious infections, particularly involving catheterization and comorbidities. The aims of this study were to evaluate the holistic activity of pomegranate rind extract (PRE), Zn (II), and PRE/Zn (II) individually and in combination against M. luteus under both planktonic and biofilm conditions. Antimicrobial activity was detected in vitro using the broth dilution method, and synergistic activity was determined using checkerboard and time-kill assays. Effects on biofilm formation and eradication were determined by crystal violet and BacLight[TM] Live/Dead staining. PRE and Zn (II) exerted antimicrobial activity against M. luteus under both planktonic and biofilm conditions. After 4 h, potent synergistic bactericidal activity was also found when PRE and Zn (II) were co-administered under planktonic conditions (log reductions: PRE 1.83 ± 0.24, Zn (II) 3.4 ± 0.08, and PRE/Zn (II) 6.88 ± 1.02; p < 0.0001). In addition, greater heterogeneity was induced in the structure of M. luteus biofilm using the PRE/Zn (II) combination compared to when PRE and Zn (II) were applied individually. The activity of PRE and the PRE/Zn (II) combination could offer a novel antimicrobial therapy for the treatment of disease-associated infections caused by M. luteus and potentially other bacteria.}, } @article {pmid34201173, year = {2021}, author = {Rumyantceva, V and Rumyantceva, V and Andreeva, Y and Tsvetikova, S and Radaev, A and Vishnevskaya, M and Vinogradov, V and Drozdov, AS and Koshel, E}, title = {Magnetically Controlled Carbonate Nanocomposite with Ciprofloxacin for Biofilm Eradication.}, journal = {International journal of molecular sciences}, volume = {22}, number = {12}, pages = {}, pmid = {34201173}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Carbonates/*chemistry ; Ciprofloxacin/*pharmacology ; Drug Carriers/chemistry ; Drug Delivery Systems ; Escherichia coli/drug effects/*growth & development ; *Magnetics ; Nanocomposites/*administration & dosage/chemistry ; Staphylococcus aureus/drug effects/*growth & development ; }, abstract = {Biofilms are the reason for a vast majority of chronic inflammation cases and most acute inflammation. The treatment of biofilms still is a complicated task due to the low efficiency of drug delivery and high resistivity of the involved bacteria to harmful factors. Here we describe a magnetically controlled nanocomposite with a stimuli-responsive release profile based on calcium carbonate and magnetite with an encapsulated antibiotic (ciprofloxacin) that can be used to solve this problem. The material magnetic properties allowed targeted delivery, accumulation, and penetration of the composite in the biofilm, as well as the rapid triggered release of the entrapped antibiotic. Under the influence of an RF magnetic field with a frequency of 210 kHz, the composite underwent a phase transition from vaterite into calcite and promoted the release of ciprofloxacin. The effectiveness of the composite was tested against formed biofilms of E. coli and S. aureus and showed a 71% reduction in E. coli biofilm biomass and an 85% reduction in S. aureus biofilms. The efficiency of the composite with entrapped ciprofloxacin was higher than for the free antibiotic in the same concentration, up to 72%. The developed composite is a promising material for the treatment of biofilm-associated inflammations.}, } @article {pmid34200637, year = {2021}, author = {Herce-Ros, N and Álvarez-Sagües, A and Álvarez-Losa, L and Nistal-Villan, E and Amador, U and Presa, J and Azabal, M}, title = {Antibacterial Ability of Sodium Hypochlorite Activated with PUI vs. XPF File against Bacteria Growth on Enterococcus faecalis Mature Biofilm.}, journal = {Dentistry journal}, volume = {9}, number = {6}, pages = {}, pmid = {34200637}, issn = {2304-6767}, abstract = {The objectives of the present study were to assess the antibacterial effectiveness of two sodium hypochlorite (NaOCl) concentrations (2.5% and 5.25%) activated by means of two techniques, passive ultrasonic irrigation (PUI) and XP-endo[®] Finisher (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) (XPF) against bacteria growth in intracanal mature biofilm. Our aim was to determine if the effect of heating up NaOCl at body temperature (BT) contributed to an improvement of the efficacy of XPF. Sixty-two single-canal human roots previously instrumented were infected with E. faecalis inoculum at 0.5 McFarland and incubated at 37 °C for two weeks. Twelve specimens were randomly selected as positive control, and the remaining fifty were divided into five experimental groups (n = 10). The first two were irrigated with 2.5 vs. 5.25% NaOCl at room temperature (RT), activated with PUI, and the other three were irrigated with XPF. Of these three, two were irrigated using 2.5 vs. 5.25% NaOCl at RT and one was irrigated with 5.25% NaOCl at BT. Our results showed that NaOCl was effective in biofilm removal for all experimental groups (p > 0.05), especially in the groups irrigated with 5.25% NaOCl at room temperature (RT) activated with PUI and the group treated with 5.25% NaOCl at BT with XPF. These groups were the most successful ones (p < 0.001). NaOCl, activated with XPF, was as effective as PUI in biofilm removal from the apical third of the canal when it was used at higher concentration and heated up. This study indicates that XPF only reached the efficacy of PUI when NaOCl was heated up.}, } @article {pmid34200008, year = {2021}, author = {Redanz, S and Enz, A and Podbielski, A and Warnke, P}, title = {Targeted Swabbing of Implant-Associated Biofilm Formation-A Staining-Guided Sampling Approach for Optimizing Routine Microbiological Diagnostics.}, journal = {Diagnostics (Basel, Switzerland)}, volume = {11}, number = {6}, pages = {}, pmid = {34200008}, issn = {2075-4418}, abstract = {Background: Swabbing of implants removed from potentially infected sites represents a time saving and ubiquitously applicable alternative to sonication approaches. The latter bears an elevated risk of processing related contaminations due to the high number of handling steps. Since biofilms are usually invisible to the naked eye, adequate swabbing relies on the chance of hitting the colonized area on the implant. A targeted directed swabbing approach could overcome this detriment. Method: Three dyes were tested at different concentrations for their toxicity on biofilm-associated cells of S. epidermidis, the species most frequently identified as a causative agent of implant-associated infections. Results: Malachite green (0.2%) delivered the highest bacterial recovery rates combined with the best results in biofilm visualization. Its suitability for diagnostic approaches was demonstrated for smooth and rough implant surfaces. Biofilm-covered areas were successfully visualized. Conclusion: Subsequent targeted swab-sampling resulted in a significantly increased bacterial recovery rate compared to a dye-free "random swabbing" diagnostic approach.}, } @article {pmid34199531, year = {2021}, author = {Neto, I and Domínguez-Martín, EM and Ntungwe, E and Reis, CP and Pesic, M and Faustino, C and Rijo, P}, title = {Dehydroabietic Acid Microencapsulation Potential as Biofilm-Mediated Infections Treatment.}, journal = {Pharmaceutics}, volume = {13}, number = {6}, pages = {}, pmid = {34199531}, issn = {1999-4923}, support = {COFAC/ILIND/CBIOS/1/2020//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {The antimicrobial activity of dehydroabietic acid (DHA) for its use as an antibiofilm agent was tested in this work. DHA was assayed against a collection of Gram-positive, Gram-negative sensitive and resistant bacteria and yeasts through the minimum inhibitory concentration (MIC), MIC with Bioburden challenge, minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), MBIC with Bioburden challenge and growth curve studies. Toxicological studies (Artemia salina, sulforhodamine B (SRB) assay) were done to assess if the compound had antimicrobial and not cytotoxic properties. Furthermore, microencapsulation and stability studies were carried out to evaluate the chemical behavior and stability of DHA. On MIC results, Gram-positive bacteria Staphylococcus aureus ATCC 1228 and Mycobacterium smegmatis ATCC 607 presented a high efficiency (7.81 µg/mL), while on Gram-negative bacteria the highest MIC value of 125 µg/mL was obtained by all Klebsiella pneumoniae strains and Escherichia coli isolate strain HSM 303. Bioburden challenge showed that MIC, MBIC and percentage biofilm inhibition (BI) values suffered alterations, therefore, having higher concentrations. MBIC values demonstrated that DHA has a higher efficiency against S. aureus ATCC 43866 with a percentage of BI of 75.13 ± 0.82% at 0.49 µg/mL. Growth curve kinetic profiles of DHA against S. aureus ATCC 25923 were observed to be bacteriostatic. DHA-alginate beads had a average size of 2.37 ± 0.20 and 2.31 ± 0.17 × 10[3] µm[2] with an encapsulation efficiency (EE%) around 99.49 ± 0.05%, a protection percentage (PP%) of 60.00 ± 0.05% in the gastric environment and a protection efficiency (PE%) around 88.12 ± 0.05% against UV light. In toxicological studies DHA has shown IC50 of 19.59 ± 7.40 µg/mL and a LC50 of 21.71 ± 2.18%. The obtained results indicate that DHA is a promising antimicrobial candidate against a wide range of bacteria and biofilm formation that must be further explored.}, } @article {pmid34199128, year = {2021}, author = {Sato, K and Naya, M and Hatano, Y and Kasahata, N and Kondo, Y and Sato, M and Takebe, K and Naito, M and Sato, C}, title = {Biofilm Spreading by the Adhesin-Dependent Gliding Motility of Flavobacterium johnsoniae: 2. Role of Filamentous Extracellular Network and Cell-to-Cell Connections at the Biofilm Surface.}, journal = {International journal of molecular sciences}, volume = {22}, number = {13}, pages = {}, pmid = {34199128}, issn = {1422-0067}, mesh = {Adhesins, Bacterial/*genetics/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Bacterial Secretion Systems/genetics/metabolism ; Biofilms/*growth & development ; Extracellular Matrix/*metabolism ; Flavobacterium/drug effects/*physiology/ultrastructure ; Microbial Sensitivity Tests ; Mutation ; Phenotype ; }, abstract = {Flavobacterium johnsoniae forms a thin spreading colony on nutrient-poor agar using gliding motility. As reported in the first paper, WT cells in the colony were sparsely embedded in self-produced extracellular polymeric matrix (EPM), while sprB cells were densely packed in immature biofilm with less matrix. The colony surface is critical for antibiotic resistance and cell survival. We have now developed the Grid Stamp-Peel method whereby the colony surface is attached to a TEM grid for negative-staining microscopy. The images showed that the top of the spreading convex WT colonies was covered by EPM with few interspersed cells. Cells exposed near the colony edge made head-to-tail and/or side-to-side contact and sometimes connected via thin filaments. Nonspreading sprB and gldG and gldK colonies had a more uniform upper surface covered by different EPMs including vesicles and filaments. The EPM of sprB, gldG, and WT colonies contained filaments ~2 nm and ~5 nm in diameter; gldK colonies did not include the latter. Every cell near the edge of WT colonies had one or two dark spots, while cells inside WT colonies and cells in SprB-, GldG-, or GldK-deficient colonies did not. Together, our results suggest that the colony surface structure depends on the capability to expand biofilm.}, } @article {pmid34198233, year = {2021}, author = {Lee, WH and Rohanizadeh, R and Loo, CY}, title = {In situ functionalizing calcium phosphate biomaterials with curcumin for the prevention of bacterial biofilm infections.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {206}, number = {}, pages = {111938}, doi = {10.1016/j.colsurfb.2021.111938}, pmid = {34198233}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/pharmacology ; Biocompatible Materials/pharmacology ; Biofilms ; *Curcumin/pharmacology ; Durapatite ; Pseudomonas aeruginosa ; *Staphylococcus aureus ; }, abstract = {This study developed a novel bioactive bone substitute (hydroxyapatite, HA) with improved anti-biofilm activity by functionalizing with curcumin (anti-biofilm compound) which provide sufficient flux of curcumin concentration for 14 days. The released curcumin acts to inhibit biofilm formation and control the number of viable planktonic cells simultaneously. To prepare curcumin-functionalized HA, different concentrations of curcumin (up to 3% w/v) were added simultaneously during the precipitation process of HA. The highest loading (50 mg/g HA) of curcumin onto HA was achieved with 2% w/v of curcumin. Physicochemical characterizations of curcumin-functionalized HA composites revealed that curcumin was successfully incorporated onto HA. Curcumin was sustainably released over 14 days, while higher curcumin release was observed in acidic condition (pH 4.4) compared to physiological (pH 7.4). The cytotoxicity assays revealed that no significant difference on bone cells growth on curcumin-functionalized HA and non-functionalized HA. Curcumin-functionalized HA was effective to inhibit bacterial cell attachment and subsequent biofilm maturation stages. The anti-biofilm effect was stronger against Staphylococcus aureus compared to Pseudomonas aeruginosa. The curcumin-functionalized HA composite significantly delayed the maturation of S. aureus compared to non-functionalized HA in which microcolonies of cells only begin to appear at 96 h. Up to 3.0 log reduction in colony forming unit (CFU)/mL of planktonic cells was noted at 24 h of incubation for both microorganisms. Thus, in this study we have suggested that curcumin loaded HA could be an alternative antimicrobial agent to control the risk of infections in post-surgical implants.}, } @article {pmid34198191, year = {2021}, author = {Ugya, AY and Ari, HA and Hua, X}, title = {Microalgae biofilm formation and antioxidant responses to stress induce by Lemna minor L., Chlorella vulgaris, and Aphanizomenon flos-aquae.}, journal = {Ecotoxicology and environmental safety}, volume = {221}, number = {}, pages = {112468}, doi = {10.1016/j.ecoenv.2021.112468}, pmid = {34198191}, issn = {1090-2414}, mesh = {Antioxidants/pharmacology ; Aphanizomenon/*physiology ; Araceae/*physiology ; *Biofilms/drug effects ; Chlorella vulgaris/*physiology ; Microalgae/*physiology ; Oxidative Stress/drug effects ; Reactive Oxygen Species ; }, abstract = {The study shows how microalgae biofilm formation and antioxidant responses to the production of reactive oxygen species (ROS) is alter by the presences of Lemna minor L., Chlorella vulgaris, and Aphanizomenon flos-aquae. The study involves the cultivation of the biofilm of Chlorella vulgaris and Aphanizomenon flos-aquae in three bioreactors. The condition of growth for the biofilm formation was varied across the three bioreactors to enable the dominance Chlorella vulgaris and Aphanizomenon flos-aquae in one of the bioreactors. Lemna minor L. was also introduce into one of the bioreactors to determine its effect on the biofilm formation. The result obtained shows that C. vulgaris and A. flos-aquae dominate the biofilm, resulting in a high level of H2O2 and O2[-] (H2O2 was 0.122 ± 0.052 and 0.183 ± 0.108 mmol/L in C. vulgaris and A. flos-aquae, respectively, and O2[-] was 0.261 ± 0.039 and 0.251 ± 0.148 mmol/L in C. vulgaris and A. flos-aquae, respectively). The study also revealed that the presence of L. minor L. tend to reduce the oxidative stress to the biofilm leading to low production of ROS (H2O2 was 0.086 ± 0.027 and 0.089 ± 0.045 mmol/L in C. vulgaris and A. flos-aquae respectively, and O2[-] was 0.185 ± 0.044 and 0.161 ± 0.065 mmol/L in C. vulgaris and A. flos-aquae respectively). The variation in the ability of the biofilm of C. vulgaris and A. flos-aquae to respond via chlorophyll, carotenoid, flavonoid, anthocyanin, superoxide dismutase, peroxidase, catalase, glutathione reductase activities, antioxidant reducing power, phosphomolybdate activity, DPPH reduction activity, H2O2 scavenging activity, lipid content and organic carbon also supports the fact that the presence of biomass of microalgae and aquatic macrophytes tend to affect the process of microalgae biofilm formation and the ability of the biofilm to produce antioxidant. This high nutrient utilization leads to the production of biomass which can be used for biofuel production and other biotechnological products.}, } @article {pmid34197998, year = {2021}, author = {Ye, J and Ren, G and Wang, C and Hu, A and Li, F and Zhou, S and He, Z}, title = {A facile and fast strategy for cathodic electroactive-biofilm assembly via magnetic nanoparticle bioconjugation.}, journal = {Biosensors & bioelectronics}, volume = {190}, number = {}, pages = {113464}, doi = {10.1016/j.bios.2021.113464}, pmid = {34197998}, issn = {1873-4235}, mesh = {Biofilms ; *Biosensing Techniques ; Carbon Dioxide ; Electrodes ; *Magnetite Nanoparticles ; Methane ; }, abstract = {Microbial electrosynthesis is a promising electricity-driven technology for converting carbon dioxide into value-added compounds, but the formation of cathodic electroactive-biofilms (CEBs) is challenging. Herein, we have demonstrated an innovative strategy for CEBs assembly via magnetic nanoparticle bioconjugation, which lies in the synergistic interactions among a bonder (Streptavidin, SA), conductive nanomaterials (Fe3O4), and a methanogen (M. barkeri). The results showed that the bioconjugated M. barkeri-SA-Fe3O4 biohybrids significantly enhanced both methane yield (33.2-fold) and faradaic efficiency (5.6-fold), compared with that of bare M. barkeri. Such an enhancement was attributed to the improved viability of CEBs with a higher biomass density. Particularly, more live cells were presented in the inner biofilms and promoted the long-distance electron exchange between the live outer-layer biofilm and the cathode electrode. Meanwhile, the higher redox activity of CEBs with the M. barkeri-SA-Fe3O4 biohybrids resulted in an improved transient charge storage capability, which was beneficial for the biological CO2-to-CH4 conversion via acting as an additional electron donor. This work has provided a new approach to accelerate the formation of CEBs and subsequent electron transfer, which holds a great potential for accomplishing electrosynthesis and CO2 fixation.}, } @article {pmid34197219, year = {2021}, author = {Liu, Y and Wu, L and Yan, Y and Yang, K and Dong, P and Luo, X and Zhang, Y and Zhu, L}, title = {Lactic Acid and Peroxyacetic Acid Inhibit Biofilm of Escherichia coli O157:H7 Formed in Beef Extract.}, journal = {Foodborne pathogens and disease}, volume = {18}, number = {10}, pages = {744-751}, doi = {10.1089/fpd.2021.0012}, pmid = {34197219}, issn = {1556-7125}, mesh = {Animals ; Biofilms ; Cattle ; Colony Count, Microbial ; *Escherichia coli O157/genetics ; Extracellular Polymeric Substance Matrix ; Lactic Acid ; Peracetic Acid/pharmacology ; Plant Extracts ; }, abstract = {The objective of this study was to evaluate the inhibitory effect of lactic acid (LA) and peroxyacetic acid (PAA) on the biofilm formation of Escherichia coli O157:H7 in beef extract (BE). BE medium was used as the growth substrate in this study, to make the control effect closer to the situation of the factory. The biofilm inhibitory efficacy of LA and PAA was tested by using a crystal violet staining assay and microscopic examination. And then, extracellular polymeric substance (EPS) production, metabolic activity, and real-time polymerase chain reaction assay were used to reveal the biofilm inhibition mechanism of LA and PAA. The results showed that both LA and PAA significantly inhibited biofilm formation of E. coli O157:H7 at minimum inhibitory concentrations (MICs) (p < 0.05). At MIC, LA and PAA showed different effects on the biofilm metabolic activity and the EPS production of E. coli O157:H7. Supporting these findings, expression analysis showed that LA significantly suppressed quorum sensing genes (luxS and sdiA) and adhesion genes (flhC), while PAA downregulated the transcription of extracellular polysaccharide synthesis genes (adrB and adrA) and the global regulatory factor csgD. This result revealed that LA and PAA had different biofilm inhibitory mechanisms on E. coli O157:H7; LA inhibited the biofilm formation mainly by inhibiting metabolic activity, while PAA inhibited EPS production. This study provided a theoretical basis for the control of E. coli O157:H7 biofilm in the actual production process.}, } @article {pmid34196746, year = {2021}, author = {Gupta, P and Gupta, H and Poluri, KM}, title = {Geraniol eradicates Candida glabrata biofilm by targeting multiple cellular pathways.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {13}, pages = {5589-5605}, pmid = {34196746}, issn = {1432-0614}, mesh = {Acyclic Monoterpenes ; Antifungal Agents/pharmacology ; *Biofilms ; Candida ; *Candida glabrata ; Microbial Sensitivity Tests ; }, abstract = {Global burden of fungal infections and associated health risk has accelerated at an incredible pace and needs to be attended at the earliest with an unbeatable therapeutic intervention. Candida glabrata is clinically the most relevant and least drug susceptible Candida species. In the pursuit of mining alternative novel drug candidates, the antifungal activity of a monoterpene phytoactive molecule geraniol (GR) against C. glabrata biofilm was evaluated. Biofilm inhibitory and eradication ability of GR evaluated against C. glabrata along with its clinical isolates. Impact of GR on various cellular pathways was evaluated to delineate its antifungal mode of action. GR has inhibited both planktonic and sessile growth of all the studied C. glabrata strains and eradicated the mature biofilm. GR reduced the carbohydrate and eDNA content, as well as hydrolytic enzyme activity in extracellular matrix of C. glabrata. The chemical profiling, microscopic, and spectroscopic studies revealed that GR targets chitin and β-glucan in cell wall. Further, results highlighted the reduction of cell membrane ergosterol content, and blocking of ABC drug efflux pump by GR which was also confirmed by RT-PCR where expression of CDR1 and ERG4 was downregulated in GR exposed C. glabrata cells. The fluorescence microscopy and flow cytometry results emphasized the alteration in mitochondrial activity, increased Ca[+2] uptake, thus changing the membrane permeability ensuing increased cytochrome C release from mitochondria to cytoplasm. Indeed, GR also has arrested cell cycle in G1/S phase and interfered with DNA replication. These observations suggest GR targets multiple cellular pathways and mediated killing of C. glabrata cells via apoptosis. In conclusion, the present study strengthens the candidacy of GR as novel antifungal therapeutic. Key points • GR inhibits growth and eradicates biofilm of C. glabrata and its clinical isolates. • GR inactivates the hydrolytic enzymes in extracellular matrix. • GR mediates C. glabrata apoptosis by interfering with multiple signaling pathways.}, } @article {pmid34196143, year = {2021}, author = {Javadi, A and Pourmand, MR and Hamedi, J and Gharebaghi, F and Baseri, Z and Mohammadzadeh, R and Eshraghi, SS}, title = {Evaluation of anti-biofilm potential of biosurfactant extracted from Nocardia species.}, journal = {Folia medica}, volume = {63}, number = {3}, pages = {392-399}, doi = {10.3897/folmed.63.e54386}, pmid = {34196143}, issn = {1314-2143}, mesh = {Biofilms ; Glycolipids ; *Nocardia/genetics ; Pseudomonas aeruginosa ; RNA, Ribosomal, 16S ; Surface-Active Agents/pharmacology ; }, abstract = {INTRODUCTION: Bacterial natural products such as biosurfactants and surface-active agents are important compounds which exhibit many applications in the fields of medicine.

AIM: The aim of the present study was to isolate and identify Nocardia strains with high biosurfactant production and antibiofilm ability.

MATERIALS AND METHODS: In the present study, a biosurfactant producing Nocardia species was isolated and identified by a laboratory method. Nocardia species were initially screened and then tested for their ability to produce biosurfactant. The oil spreading test and the surface tension measurements showed that one strain was a biosurfactant producer. The strain with the best surface activity results was selected for further studies and identified by 16S rRNA gene sequencing method. Fourier transform infrared spectroscopy (FTIR) and compositional analysis proved a biosurfactant structure.

RESULTS: Oil spreading test and blue agar plate test confirmed biosurfactants and extracellular anionic glycolipids. E24% assay using olive oil revealed strong emulsifying characteristic of the extracted biosurfactant with 100% emulsifying strength. FTIR spectrum indicated the presence of aliphatic hydrocarbon chain (lipid) along with the polysaccharide portion, confirming the glycolipid nature of the biosurfactant. The stability of the biosurfactant produced in different conditions was significant. Increasing concentration of BS significantly inhibited Pseudomonas aeruginosa biofilm.

CONCLUSIONS: N. coubleae can be a representative of the genus Nocardia for the production of biosurfactants with beneficial physicochemical properties.}, } @article {pmid34195563, year = {2021}, author = {Chaudhary, S and Singh, R and Yadav, S and Patil, SA}, title = {Electrochemical enrichment of haloalkaliphilic nitrate-reducing microbial biofilm at the cathode of bioelectrochemical systems.}, journal = {iScience}, volume = {24}, number = {6}, pages = {102682}, pmid = {34195563}, issn = {2589-0042}, abstract = {Electrotrophic microorganisms have not been well studied in extreme environments. Here, we report on the nitrate-reducing cathodic microbial biofilm from a haloalkaline environment. The biofilm enriched via electrochemical approach under 9.5 pH and 20 g NaCl/L salinity conditions achieved - 43.5 ± 7.2 μA / cm 2 current density and 49.5 ± 13.2 % nitrate reduction efficiency via partial and complete denitrification. Voltammetric characterization of the biocathodes revealed a redox center with - 0.294 ± 0.003 V (vs. Ag/AgCl) formal potential putatively involved in the electron uptake process. The lack of soluble redox mediators and hydrogen-driven nitrate reduction suggests direct-contact cathodic electron uptake by the nitrate-reducing microorganisms in the enriched biofilm. 16S-rRNA amplicon sequencing of the cathodic biofilm revealed the presence of unreported Pseudomonas, Natronococcus, and Pseudoalteromonas spp. at 31.45 % , 11.82 % , and 9.69 % relative sequence abundances, respectively. The enriched nitrate-reducing microorganisms also reduced nitrate efficiently using soluble electron donors found in the lake sediments, thereby suggesting their role in N-cycling in such environments.}, } @article {pmid34194732, year = {2021}, author = {Hutauruk, SM and Hermani, B and Monasari, P}, title = {Role of chlorhexidine on tracheostomy cannula decontamination in relation to the growth of Biofilm-Forming Bacteria Colony- a randomized controlled trial study.}, journal = {Annals of medicine and surgery (2012)}, volume = {67}, number = {}, pages = {102491}, pmid = {34194732}, issn = {2049-0801}, abstract = {BACKGROUND: Regular cleaning of the cannula in the trachea is very important for infection prevention. How to wash the tracheal cannula which is good to reduce the possibility of colonies of biofilm-forming bacteria and the growth of bacterial and the pattern of bacterial on the tracheal cannula is still unknown. This study aims to evaluate the efficacy of decontamination of the tracheal cannula using chlorhexidine and NaCl 0.9% in patients using the tracheal cannula to decrease biofilm-forming bacterial colony.

METHODS: 40 subjects were grouped into 20 subjects in the control group washing the cannula using 0.9% NaCl and the interventional group washing cannula using and with 2.5% chlorhexidine solution and 0.9% NaCl. This study used a parallel randomized controlled trial of 2 groups with a single blinded.

RESULTS: 40 subjects studied, 17 subjects (85%) each group produced biofilm-forming bacteria prior to intervention. After intervention in the study group, 15 subjects were biofilm negative and 5 biofilm positive subjects p = 0.001. The most common bacteria found in the control group is Pseudomonas aeruginosa, while in the study group some bacteria such as Acinetobacter sp. and Proteus mirabilis. Amoxicilin-Clavulanate had the highest resistance to biofilm forming bacteria in both groups. Piperacillin, ceftazidime, ciprofloxacin and meropenem have the highest sensitivity to biofilm-forming bacteria.

CONCLUSION: There was a significant decrease in the number of colonies that produced biofilm in the tracheal cannula in the study group compared to the control group in tracheal cannula washing.}, } @article {pmid34194407, year = {2021}, author = {Erben, J and Pinder, ZA and Lüdtke, MS and Kerzenmacher, S}, title = {Local Acidification Limits the Current Production and Biofilm Formation of Shewanella oneidensis MR-1 With Electrospun Anodes.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {660474}, pmid = {34194407}, issn = {1664-302X}, abstract = {The anodic current production of Shewanella oneidensis MR-1 is typically lower compared to other electroactive bacteria. The main reason for the low current densities is the poor biofilm growth on most anode materials. We demonstrate that the high current production of Shewanella oneidensis MR-1 with electrospun anodes exhibits a similar threshold current density as dense Geobacter spp biofilms. The threshold current density is a result of local acidification in the biofilm. Increasing buffer concentration from 10 to 40 mM results in a 1.8-fold increase of the current density [(590 ± 25) μA cm[-2]] while biofilm growth stimulation by riboflavin has little effect on the current production. The current production of a reference material below the threshold did not respond to the increased buffer concentration but could be enhanced by supplemented riboflavin that stimulated the biofilm growth. Our results suggest that the current production with S. oneidensis is limited (1) by the biofilm growth on the anode that can be enhanced by the choice of the electrode material, and (2) by the proton transport through the biofilm and the associated local acidification.}, } @article {pmid34193659, year = {2022}, author = {Fukushima, Y and Tsuyuki, Y and Goto, M and Yoshida, H and Takahashi, T}, title = {Biofilm Production Ability and Other Microbiological Features of Streptococcus canis.}, journal = {Japanese journal of infectious diseases}, volume = {75}, number = {1}, pages = {63-69}, doi = {10.7883/yoken.JJID.2020.1086}, pmid = {34193659}, issn = {1884-2836}, mesh = {Animals ; Biofilms ; Dogs ; Genotype ; *Streptococcal Infections ; Streptococcus ; }, abstract = {This study assessed the biofilm production ability (BPA) and other microbiological features of Streptococcus canis strains. Forty strains of companion-animal origin, including the host information, from 2015 and 2017 were randomly selected, and three strains of blood-origin from two humans and one dog were included. We measured BPA using crystal violet staining, along with S. canis M-like protein (SCM) allele typing, sequence type (ST) determination, antimicrobial resistance (AMR) phenotyping/genotyping, and virulence-associated gene profiling (gbp, ap1, fp1, and brp). BPA measurements revealed 35 strains with BPA and 48 strains without BPA. There was an association between the producer and the isolation year (2017). Moreover, we observed an association between the non-producer and SCM allele 1 and ST9, and between the producer and SCM allele 10 and ST21. Furthermore, we observed a correlation between the producer and the presence of AMR genotypes. Specifically, there was an association between the producer and ap1 detection, and between non-producer and gbp detection. Our results suggest a correlation between biofilm producers and other microbiological features (i.e. isolation year, SCM allele type 10, ST21, presence of AMR genotypes, and ap1 detection).}, } @article {pmid34192637, year = {2021}, author = {Li, P and Li, K and Xu, P and Liu, X and Pu, Y}, title = {Treatment of wastewater with high carbon-to-nitrogen ratio using a waterfall aeration biofilm reactor combined with sequencing batch reactor: Microbial community structure and metabolism analysis.}, journal = {Bioresource technology}, volume = {337}, number = {}, pages = {125450}, doi = {10.1016/j.biortech.2021.125450}, pmid = {34192637}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Carbon ; Denitrification ; *Microbiota ; Nitrification ; Nitrogen ; RNA, Ribosomal, 16S/genetics ; *Wastewater ; }, abstract = {A low-cost and high-efficiency waterfall aeration biofilm reactor (WABR) combined with a sequencing batch reactor (SBR) was established to treat wastewater with a C/N ratio of 50. Three WABR-SBR systems with different fillers were used. In the stable operation phase, the removal efficiency of chemical oxygen demand was R1 (approximately 99%), R2 (97-99%), and R3 (96-99%); the effluent concentration of NH4[+]-N was 0.5 mg/L without nitrite or nitrate accumulation. High-throughput 16S rRNA sequencing revealed that the dominant phyla in the microbial community structure were Proteobacteria, Bacteroidetes, and Planctomycetes. Quantitative PCR was used to quantify the nitrification and denitrification gene expressions (Nitrobacter, nirS, and nirK) to evaluate the simultaneous nitrification and denitrification processes. Both anammox and denitrifying bacteria were abundant. Metagenomic annotation of genes that revealed the metabolic pathways of carbohydrates, amino acids, and the two dominant enzymes (GH and GT) provide valuable information for microbial ecology analysis.}, } @article {pmid34191684, year = {2021}, author = {Salcedo Moyano, AJ and Delforno, TP and Subtil, EL}, title = {Simultaneous nitrification-denitrification (SND) using a thermoplastic gel as support: pollutants removal and microbial community in a pilot-scale biofilm membrane bioreactor.}, journal = {Environmental technology}, volume = {}, number = {}, pages = {1-15}, doi = {10.1080/09593330.2021.1950843}, pmid = {34191684}, issn = {1479-487X}, abstract = {In this study, experiments were carried out to treat sanitary wastewater in a biofilm membrane bioreactor using a thermoplastic gel as a support to assist the nitrification-denitrification process. For this purpose, the system was operated in two different dissolved oxygen concentrations (2.3 ± 0.2 and 0.9 ± 0.3 mg O2/L for Phases I and II, respectively) and the removal of organic compounds and nitrogen, as well as the microbial community in suspended biomass and biofilm were evaluated. The MB-MBR system was able to withstand raw wastewater variations and maintaining a low permeate COD concentration (18 mg/L) even at low DO concentrations. On the other hand, it was found that oxygen concentration significantly influenced the process of nitrogen conversion. In Phase I the average removal of total nitrogen was 18 ± 8%, while in Phase II it increased to 66 ± 11%. The denitrification rate was two times higher (7.8 mg NO3--N/h) at low dissolved oxygen, with a significant contribution of the biofilm (41%). Additionally, the high-throughput 16S rDNA sequencing showed that the oxygen concentration was determinant for arrangement patterns of the samples and not the sampling site (suspended biomass and support material). Thiothrix, Comamonas, Rhodobacter, Mycobacterium, Thermomonas, Sphingobium, Sphigopyxis, Pseudoxanthomonas, Nitrospira and, Novosphingobium were the main genera regarding the nitrogen cycle.}, } @article {pmid34190605, year = {2021}, author = {Jiménez Otero, F and Chadwick, GL and Yates, MD and Mickol, RL and Saunders, SH and Glaven, SM and Gralnick, JA and Newman, DK and Tender, LM and Orphan, VJ and Bond, DR}, title = {Evidence of a Streamlined Extracellular Electron Transfer Pathway from Biofilm Structure, Metabolic Stratification, and Long-Range Electron Transfer Parameters.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {17}, pages = {e0070621}, pmid = {34190605}, issn = {1098-5336}, support = {R01 AI127850/AI/NIAID NIH HHS/United States ; 1R01AI127850-01A1//HHS | National Institutes of Health (NIH)/ ; }, mesh = {*Biofilms ; Electricity ; Electrodes ; Electron Transport ; Extracellular Space/chemistry/*metabolism ; Geobacter/*chemistry/growth & development/*physiology ; }, abstract = {A strain of Geobacter sulfurreducens, an organism capable of respiring solid extracellular substrates, lacking four of five outer membrane cytochrome complexes (extABCD[+] strain) grows faster and produces greater current density than the wild type grown under identical conditions. To understand cellular and biofilm modifications in the extABCD[+] strain responsible for this increased performance, biofilms grown using electrodes as terminal electron acceptors were sectioned and imaged using electron microscopy to determine changes in thickness and cell density, while parallel biofilms incubated in the presence of nitrogen and carbon isotopes were analyzed using NanoSIMS (nanoscale secondary ion mass spectrometry) to quantify and localize anabolic activity. Long-distance electron transfer parameters were measured for wild-type and extABCD[+] biofilms spanning 5-μm gaps. Our results reveal that extABCD[+] biofilms achieved higher current densities through the additive effects of denser cell packing close to the electrode (based on electron microscopy), combined with higher metabolic rates per cell compared to the wild type (based on increased rates of [15]N incorporation). We also observed an increased rate of electron transfer through extABCD[+] versus wild-type biofilms, suggesting that denser biofilms resulting from the deletion of unnecessary multiheme cytochromes streamline electron transfer to electrodes. The combination of imaging, physiological, and electrochemical data confirms that engineered electrogenic bacteria are capable of producing more current per cell and, in combination with higher biofilm density and electron diffusion rates, can produce a higher final current density than the wild type. IMPORTANCE Current-producing biofilms in microbial electrochemical systems could potentially sustain technologies ranging from wastewater treatment to bioproduction of electricity if the maximum current produced could be increased and current production start-up times after inoculation could be reduced. Enhancing the current output of microbial electrochemical systems has been mostly approached by engineering physical components of reactors and electrodes. Here, we show that biofilms formed by a Geobacter sulfurreducens strain producing ∼1.4× higher current than the wild type results from a combination of denser cell packing and higher anabolic activity, enabled by an increased rate of electron diffusion through the biofilms. Our results confirm that it is possible to engineer electrode-specific G. sulfurreducens strains with both faster growth on electrodes and streamlined electron transfer pathways for enhanced current production.}, } @article {pmid34190008, year = {2021}, author = {Kim, HS and Ashrafudoulla, M and Kim, BR and Mizan, MFR and Jung, SJ and Sadekuzzaman, M and Park, SH and Ha, SD}, title = {The application of bacteriophage to control Cronobacter sakazakii planktonic and biofilm growth in infant formula milk.}, journal = {Biofouling}, volume = {37}, number = {6}, pages = {606-614}, doi = {10.1080/08927014.2021.1943741}, pmid = {34190008}, issn = {1029-2454}, mesh = {Animals ; *Bacteriophages ; Biofilms ; *Cronobacter sakazakii ; Food Microbiology ; Humans ; Infant ; Infant Formula ; Milk ; Plankton ; }, abstract = {The goal was to identify the biofilm-forming ability of Cronobacter sakazakii on surfaces of stainless steel (SS) and silicone rubber (SR) in contact with infant formula milk. Two representative bacteriophages (PBES04 and PBES19) were used to control the growth of C. sakazakii as well as its biofilm forming ability on either SS or SR surfaces. Bacterial growth was confirmed at 20 °C when PBES04 and PBES19 were used, whereas C. sakazakii was not normally detected in infant formula milk treated with both bacteriophages for 6 h. In an additional biofilm reduction experiment, the biofilm on SS or SR surfaces were reduced by 3.07 and 1.92 log CFU cm[-2], respectively after PBES04 treatment, and 3.06 and 2.14 log CFU cm[-2], respectively, after PBES19 treatment. These results demonstrate that bacteriophages can be effective in inactivating C. sakazakii in biofilms which could potentially increase food safety in commercial facilities.}, } @article {pmid34187390, year = {2021}, author = {Zhang, Z and Cao, Y and Li, Y and Chen, X and Ding, C and Liu, Y}, title = {Risk factors and biofilm formation analyses of hospital-acquired infection of Candida pelliculosa in a neonatal intensive care unit.}, journal = {BMC infectious diseases}, volume = {21}, number = {1}, pages = {620}, pmid = {34187390}, issn = {1471-2334}, mesh = {Antifungal Agents/therapeutic use ; *Biofilms ; Candidiasis/drug therapy/*epidemiology/microbiology/*prevention & control ; Case-Control Studies ; China/epidemiology ; Cross Infection/drug therapy/*epidemiology/microbiology/*prevention & control ; Disease Outbreaks/*prevention & control ; Equipment and Supplies/*microbiology ; Female ; Health Personnel ; Humans ; Infant, Newborn ; Infection Control/methods ; *Intensive Care Units, Neonatal ; Length of Stay ; Male ; Microbial Sensitivity Tests ; RNA, Fungal/genetics ; Risk Factors ; Saccharomycetales/*genetics/isolation & purification ; }, abstract = {BACKGROUND: Candida pelliculosa is an ecological fungal species that can cause infections in immunocompromised individuals. Numerous studies globally have shown that C. pelliculosa infects neonates. An outbreak recently occurred in our neonatal intensive care unit; therefore, we aimed to evaluate the risk factors in this hospital-acquired fungal infection.

METHODS: We performed a case-control study, analysing the potential risk factors for neonatal infections of C. pelliculosa so that infection prevention and control could be implemented in our units. Isolated strains were tested for drug resistance and biofilm formation, important factors for fungal transmission that give rise to hospital-acquired infections.

RESULTS: The use of three or more broad-spectrum antimicrobials or long hospital stays were associated with higher likelihoods of infection with C. pelliculosa. The fungus was not identified on the hands of healthcare workers or in the environment. All fungal isolates were susceptible to anti-fungal medications, and after anti-fungal treatment, all infected patients recovered. Strict infection prevention and control procedures efficiently suppressed infection transmission. Intact adhesin-encoding genes, shown by genome analysis, indicated possible routes for fungal transmission.

CONCLUSIONS: The use of three or more broad-spectrum antimicrobials or a lengthy hospital stay is theoretically associated with the risk of infection with C. pelliculosa. Strains that we isolated are susceptible to anti-fungal medications, and these were eliminated by treating all patients with an antifungal. Transmission is likely via adhesion to the cell surface and biofilm formation.}, } @article {pmid34186084, year = {2021}, author = {Yang, G and Mai, Q and Zhuang, Z and Zhuang, L}, title = {Buffer capacity regulates the stratification of anode-respiring biofilm during brewery wastewater treatment.}, journal = {Environmental research}, volume = {201}, number = {}, pages = {111572}, doi = {10.1016/j.envres.2021.111572}, pmid = {34186084}, issn = {1096-0953}, mesh = {*Biofilms ; Electrodes ; *Water Purification ; }, abstract = {Improving the buffer capacity of the electrolyte can enhance the anode performance in bioelectrochemical systems (BESs). To elucidate the mechanism underlying the facilitated BESs performance, this study used three different anode biofilms cultured with different concentrations of phosphate buffer (5, 50 and 100 mM) to investigate the biofilm response, in terms of the spatial structure of metabolic activity and microbial community, to different buffer capacities. Results showed that the electrochemical activities of the anode biofilms positively correlated with the buffer concentration. The spatial stratification of metabolic activity and microbial community of the anode biofilms were regulated by the buffer capacity, and the spatial microbial heterogeneity of the anode biofilm decreased as the buffer concentration increased. With increasing buffer capacity, Geobacter spp. were enriched in both the inner and outer layers of the biofilm, and the inhibition of methanogens growth improved the COD removal attributed to anode respiration. Additionally, the stimulation of EPS production in biofilms played a role in increasing the electrochemical performance of biofilms by buffer improvement. This study first revealed the regulation of buffer capacity on the stratification of anode biofilm during brewery wastewater treatment, which provided a deep insight into the relation of biofilm structure to its electrochemical properties.}, } @article {pmid34186004, year = {2021}, author = {Pires, DP and Melo, LDR and Azeredo, J}, title = {Understanding the Complex Phage-Host Interactions in Biofilm Communities.}, journal = {Annual review of virology}, volume = {8}, number = {1}, pages = {73-94}, doi = {10.1146/annurev-virology-091919-074222}, pmid = {34186004}, issn = {2327-0578}, mesh = {Bacteria ; *Bacteriophages/genetics ; Biofilms ; }, abstract = {Bacteriophages and bacterial biofilms are widely present in natural environments, a fact that has accelerated the evolution of phages and their bacterial hosts in these particular niches. Phage-host interactions in biofilm communities are rather complex, where phages are not always merely predators but also can establish symbiotic relationships that induce and strengthen biofilms. In this review we provide an overview of the main features affecting phage-biofilm interactions as well as the currently available methods of studying these interactions. In addition, we address the applications of phages for biofilm control in different contexts.}, } @article {pmid34184515, year = {2021}, author = {Ratajczak, M and Kamińska, D and Nowak-Malczewska, DM and Schneider, A and Dlugaszewska, J}, title = {Relationship between antibiotic resistance, biofilm formation, genes coding virulence factors and source of origin of Pseudomonas aeruginosa clinical strains.}, journal = {Annals of agricultural and environmental medicine : AAEM}, volume = {28}, number = {2}, pages = {306-313}, doi = {10.26444/aaem/122682}, pmid = {34184515}, issn = {1898-2263}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; *Biofilms/drug effects ; *Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Virulence Factors/*genetics/metabolism ; }, abstract = {INTRODUCTION AND OBJECTIVE: Pseudomonas aeruginosa is an opportunistic pathogen that causes difficult with treating infections, especially in the immunocompromised and patients with some underlying disease. The aim of the study is to assess the antibiotic resistance, biofilm formation, and the presence of genes encoding various virulence factors in clinical isolates of P. aeruginosa.

MATERIAL AND METHODS: Seventy-three clinical isolates of Pseudomonas aeruginosa were tested. Antimicrobial Susceptibility Testing (AST) and carbapenemases production was performed in accordance with the EUCAST guidelines. The ability to form biofilm was assessed by crystal violet assay. Genes encoding selected virulence factors were detected using standard polymerase chain reaction (PCR).

RESULTS: Among the 73 clinical isolates of P. aeruginosa, 41.1% were resistant to imipenem, 61.6% to meropenem, 30.1% to ciprofloxacin and 15.1% to tobramycin. Over 20% of isolates were producers of MBL. Antibiotic resistance profiling revealed that 23.3% of strains were sensitive to all antibiotics, 60.3% were LDR phenotype, and 16.4% were MDR phenotype. The majority of strains (73.6%) were strong-biofilm producers, 17.0% were moderate and 9.4% were weak biofilm producers. PCR analysis showed the presence of lasB, aprE and prpL genes in most of the tested strains (93.1%, 87.7% and 74.0%, respectively). Among strong biofilm producers, 22.2% were MDR, 63.0% of strains represented LDR phenotype, and 14.8% were sensitive to all antibiotics. Moderate and weak biofilm producers were LDR and sensitive phenotypes only (respectively, 58.3% and 42.9 - LDR, 41.7 and 51.7% - sensitive).

CONCLUSIONS: High frequency of MDR strains and their ability of biofilm formation and virulence factors may be a threat to effective therapy, and can increase morbidity and mortality of infected patients.}, } @article {pmid34184296, year = {2021}, author = {Dilhari, A and Weerasekera, M and Gunasekara, C and Pathirage, S and Fernando, N and Weerasekara, D and McBain, AJ}, title = {Biofilm prevalence and microbial characterisation in chronic wounds in a Sri Lankan cohort.}, journal = {Letters in applied microbiology}, volume = {73}, number = {4}, pages = {477-485}, doi = {10.1111/lam.13532}, pmid = {34184296}, issn = {1472-765X}, support = {ASP/01/RE/MED/2016/50//University of Sri Jayewardenepura/ ; 2015/67//Ministry of Health, Sri Lanka/ ; }, mesh = {Bacteria/genetics ; *Biofilms ; Humans ; Microscopy, Electron, Scanning ; Prevalence ; *Wound Infection ; }, abstract = {Biofilms have been associated with chronic wound infections in diabetic patients. The study assessed the occurrence of biofilms in chronic diabetic wounds (CDWs) in a Sri Lankan cohort. Tissue specimens collected during surgical debridement were analysed by quantitative differential viable counting, scanning electron microscopy (SEM), fluorescence insitu hybridization (FISH) and light microscopy with Gram and Haematoxylin-Eosin staining. All specimens harboured >5·0 log10 CFU per g bacteria and 2-9 distinct species per specimen were recovered from twenty wounds by culture. The most frequently isolated bacterium was Pseudomonas spp. (12/20;60%). Strict anaerobes were isolated from 10/20 specimens. Gram and Haematoxylin-Eosin staining showed aggregated micro-colonies, embedded in the wound tissue bed (20/20) but the exopolymer matrix was not visible in all samples (13/20). Fluorescence microscopy using a eubacteria-specific FISH probe indicated the presence of bacterial aggregates within the deep layers of the wound tissues (20/20). SEM revealed the presumptive architecture of matrix-embedded microbial clusters (20/20). The approximate diameter of bacterial aggregates in tissues ranged between 12 and 400 µm. Bacterial infiltration into the internal portions of the tissues was apparent using FISH, Gram, and Haematoxylin-Eosin staining. All CDWs carried biofilm-specific morphological features. FISH was more specific than SEM and indicated the presence of microcolonies within deeper tissues.}, } @article {pmid34182551, year = {2022}, author = {Tsikopoulos, A and Petinaki, E and Festas, C and Tsikopoulos, K and Meroni, G and Drago, L and Skoulakis, C}, title = {In vitro Inhibition of Biofilm Formation on Silicon Rubber Voice Prosthesis: Α Systematic Review and Meta-Analysis.}, journal = {ORL; journal for oto-rhino-laryngology and its related specialties}, volume = {84}, number = {1}, pages = {10-29}, doi = {10.1159/000516345}, pmid = {34182551}, issn = {1423-0275}, mesh = {Bacteria ; Biofilms ; Humans ; *Larynx, Artificial/microbiology ; Silicon/pharmacology ; Silicone Elastomers/pharmacology ; }, abstract = {INTRODUCTION: Biofilm formation on voice prostheses is the primary reason for their premature implant dysfunction. Multiple strategies have been proposed over the last decades to achieve inhibition of biofilm formation on these devices. The purpose of this study was to assess the results of the available in vitro biofilm inhibition modalities on silicone rubber voice prostheses.

METHODS: We conducted a systematic search in PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases up to February 29, 2020. A total of 33 in vitro laboratory studies investigating the efficacy of different coating methods against Candida, Staphylococcus, Streptococcus, Lactobacilli, and Rothia biofilm growth on silicone rubber medical devices were included. Subgroup analysis linked to the type of prevention modality was carried out, and quality assessment was performed with the use of the modified CONSORT tool.

RESULTS: Data from 33 studies were included in qualitative analysis, of which 12 qualified for quantitative analysis. For yeast biofilm formation assessment, there was a statistically significant difference in favor of the intervention group (standardized mean difference [SMD] = -1.20; 95% confidence interval [CI] [-1.73, -0.66]; p < 0.0001). Subgroup analysis showed that combined methods (active and passive surface modification) are the most effective for biofilm inhibition in yeast (SMD = -2.53; 95% CI [-4.02, -1.03]; p = 0.00001). No statistically significant differences between intervention and control groups were shown for bacterial biofilm inhibition (SMD = -0.09; 95% CI [-0.68, 0.46]; p = 0.65), and the results from the subgroup analysis found no notable differences between the surface modification methods. After analyzing data on polymicrobial biofilms, a statistically significant difference in favor of prevention methods in comparison with the control group was detected (SMD = -2.59; 95% CI [-7.48, 2.31]; p = 0.30).

CONCLUSIONS: The meta-analysis on biofilm inhibition demonstrated significant differences in favor of yeast biofilm inhibition compared to bacteria. A stronger inhibition with the application of passive or combined active and passive surface modification techniques was reported.}, } @article {pmid34182306, year = {2021}, author = {Guzzon, A and Di Pippo, F and Bonavita, S and Congestri, R}, title = {Influence of light and flow on taxon composition and photosynthesis of marine phototrophic biofilm in photobioreactors.}, journal = {Marine environmental research}, volume = {169}, number = {}, pages = {105395}, doi = {10.1016/j.marenvres.2021.105395}, pmid = {34182306}, issn = {1879-0291}, mesh = {Biofilms ; *Cyanobacteria ; *Diatoms ; Photobioreactors ; Photosynthesis ; }, abstract = {In this study, marine biofilms were cultured in a flow-lane, semi-continuous photobioreactor at different irradiances and flows to evaluate their combined effect on biofilms' phototrophic composition and photosynthetic activity. Taxon richness, evaluated by different microscopy techniques, including transmission and scanning electron microscopy, resulted to be heavily reduced from source communities to mature cultures. The strongest decrease was observed for diatoms, which were overcome by cyanobacteria and green algae over time. Photosynthetic performance was investigated by pulse amplitude modulated fluorescence. Irradiance was the main driver of data distribution of the photosynthetic parameters rel.ETRmax and Ik, while flow rate affected α and ΔF/Fm'. The combination of irradiance and flow rate affected ΔF/Fm' reflecting the photosynthetic performance of the most relatively abundant taxa. Higher ΔF/Fm' was attained when cyanobacteria and green algae were dominating, whilst lower ΔF/Fm' when diatoms occurred in the initial phase of biofilm development.}, } @article {pmid34181389, year = {2021}, author = {Munoz, M and El-Khoury, A and Eren Cimenci, C and Gonzalez-Gomez, M and Hunter, RA and Lomboni, D and Variola, F and Rotstein, BH and Vono, LLR and Rossi, LM and Edwards, AM and Alarcon, EI}, title = {Riboflavin Surface Modification of Poly(vinyl chloride) for Light-Triggered Control of Bacterial Biofilm and Virus Inactivation.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {27}, pages = {32251-32262}, doi = {10.1021/acsami.1c08042}, pmid = {34181389}, issn = {1944-8252}, mesh = {Bacterial Physiological Phenomena/drug effects/radiation effects ; Biofilms/*drug effects/radiation effects ; *Light ; Microbial Viability/*drug effects/radiation effects ; Polyvinyl Chloride/*chemistry/*pharmacology ; Riboflavin/*chemistry ; Virus Inactivation/*drug effects/radiation effects ; }, abstract = {Poly(vinyl chloride) (PVC) is the most used biomedical polymer worldwide. PVC is a stable and chemically inert polymer. However, microorganisms can colonize PVC producing biomedical device-associated infections. While surface modifications of PVC can help improve the antimicrobial and antiviral properties, the chemically inert nature of PVC makes those modifications challenging and potentially toxic. In this work, we modified the PVC surface using a derivative riboflavin molecule that was chemically tethered to a plasma-treated PVC surface. Upon a low dosage of blue light, the riboflavin tethered to the PVC surface became photochemically activated, allowing for Pseudomonas aeruginosa bacterial biofilm and lentiviral in situ eradication.}, } @article {pmid34180604, year = {2021}, author = {Nordgaard, M and Mortensen, RMR and Kirk, NK and Gallegos-Monterrosa, R and Kovács, ÁT}, title = {Deletion of Rap-Phr systems in Bacillus subtilis influences in vitro biofilm formation and plant root colonization.}, journal = {MicrobiologyOpen}, volume = {10}, number = {3}, pages = {e1212}, pmid = {34180604}, issn = {2045-8827}, mesh = {Arabidopsis/microbiology ; Bacillus subtilis/*genetics/*growth & development/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Plant Roots/*microbiology ; }, abstract = {Natural isolates of the soil-dwelling bacterium Bacillus subtilis form robust biofilms under laboratory conditions and colonize plant roots. B. subtilis biofilm gene expression displays phenotypic heterogeneity that is influenced by a family of Rap-Phr regulatory systems. Most Rap-Phr systems in B. subtilis have been studied independently, in different genetic backgrounds and under distinct conditions, hampering true comparison of the Rap-Phr systems' impact on bacterial cell differentiation. Here, we investigated each of the 12 Rap-Phr systems of B.subtilis NCIB 3610 for their effect on biofilm formation. By studying single ∆rap-phr mutants, we show that despite redundancy between the cell-cell communication systems, deletion of each of the 12 Rap-Phr systems influences matrix gene expression. These Rap-Phr systems therefore enable fine-tuning of the timing and level of matrix production in response to specific conditions. Furthermore, some of the ∆rap-phr mutants demonstrated altered biofilm formation in vitro and colonization of Arabidopsis thaliana roots, but not necessarily similarly in both processes, indicating that the pathways regulating matrix gene expression and other factors important for biofilm formation may be differently regulated under these distinct conditions.}, } @article {pmid34178723, year = {2021}, author = {Fourie, R and Albertyn, J and Sebolai, O and Gcilitshana, O and Pohl, CH}, title = {Candida albicans SET3 Plays a Role in Early Biofilm Formation, Interaction With Pseudomonas aeruginosa and Virulence in Caenorhabditis elegans.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {680732}, pmid = {34178723}, issn = {2235-2988}, mesh = {Animals ; Biofilms ; Caenorhabditis elegans ; *Candida albicans/genetics ; *Pseudomonas aeruginosa/genetics ; Virulence ; }, abstract = {The yeast Candida albicans exhibits multiple morphologies dependent on environmental cues. Candida albicans biofilms are frequently polymicrobial, enabling interspecies interaction through proximity and contact. The interaction between C. albicans and the bacterium, Pseudomonas aeruginosa, is antagonistic in vitro, with P. aeruginosa repressing the yeast-to-hyphal switch in C. albicans. Previous transcriptional analysis of C. albicans in polymicrobial biofilms with P. aeruginosa revealed upregulation of genes involved in regulation of morphology and biofilm formation, including SET3, a component of the Set3/Hos2 histone deacetylase complex (Set3C). This prompted the question regarding the involvement of SET3 in the interaction between C. albicans and P. aeruginosa, both in vitro and in vivo. We found that SET3 may influence early biofilm formation by C. albicans and the interaction between C. albicans and P. aeruginosa. In addition, although deletion of SET3 did not alter the morphology of C. albicans in the presence of P. aeruginosa, it did cause a reduction in virulence in a Caenorhabditis elegans infection model, even in the presence of P. aeruginosa.}, } @article {pmid34177868, year = {2021}, author = {Brauer, M and Lassek, C and Hinze, C and Hoyer, J and Becher, D and Jahn, D and Sievers, S and Riedel, K}, title = {What's a Biofilm?-How the Choice of the Biofilm Model Impacts the Protein Inventory of Clostridioides difficile.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {682111}, pmid = {34177868}, issn = {1664-302X}, abstract = {The anaerobic pathogen Clostridioides difficile is perfectly equipped to survive and persist inside the mammalian intestine. When facing unfavorable conditions C. difficile is able to form highly resistant endospores. Likewise, biofilms are currently discussed as form of persistence. Here a comprehensive proteomics approach was applied to investigate the molecular processes of C. difficile strain 630Δerm underlying biofilm formation. The comparison of the proteome from two different forms of biofilm-like growth, namely aggregate biofilms and colonies on agar plates, revealed major differences in the formation of cell surface proteins, as well as enzymes of its energy and stress metabolism. For instance, while the obtained data suggest that aggregate biofilm cells express both flagella, type IV pili and enzymes required for biosynthesis of cell-surface polysaccharides, the S-layer protein SlpA and most cell wall proteins (CWPs) encoded adjacent to SlpA were detected in significantly lower amounts in aggregate biofilm cells than in colony biofilms. Moreover, the obtained data suggested that aggregate biofilm cells are rather actively growing cells while colony biofilm cells most likely severely suffer from a lack of reductive equivalents what requires induction of the Wood-Ljungdahl pathway and C. difficile's V-type ATPase to maintain cell homeostasis. In agreement with this, aggregate biofilm cells, in contrast to colony biofilm cells, neither induced toxin nor spore production. Finally, the data revealed that the sigma factor SigL/RpoN and its dependent regulators are noticeably induced in aggregate biofilms suggesting an important role of SigL/RpoN in aggregate biofilm formation.}, } @article {pmid34177820, year = {2021}, author = {Haque, MM and Mosharaf, MK and Haque, MA and Tanvir, MZH and Alam, MK}, title = {Biofilm Formation, Production of Matrix Compounds and Biosorption of Copper, Nickel and Lead by Different Bacterial Strains.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {615113}, pmid = {34177820}, issn = {1664-302X}, abstract = {Bacterial biofilms play a key role in metal biosorption from wastewater. Recently, Enterobacter asburiae ENSD102, Enterobacter ludwigii ENSH201, Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, and Bacillus thuringiensis ENSW401 were shown to form air-liquid (AL) and solid-air-liquid (SAL) biofilms in a static condition at 28 and 37°C, respectively. However, how environmental and nutritional conditions affect biofilm formation; production of curli and cellulose; and biosorption of copper (Cu), nickel (Ni), and lead (Pb) by these bacteria have not been studied yet. In this study, E. asburiae ENSD102, E. ludwigii ENSH201, and B. thuringiensis ENSW401 developed the SAL biofilms at pH 8, while E. asburiae ENSD102 and Vitreoscilla sp. ENSG301 constructed the SAL biofilms at pH 4. However, all these strains produced AL biofilms at pH 7. In high osmolarity and ½-strength media, all these bacteria built fragile AL biofilms, while none of these strains generated the biofilms in anaerobic conditions. Congo red binding results showed that both environmental cues and bacterial strains played a vital role in curli and cellulose production. Calcofluor binding and spectrophotometric results revealed that all these bacterial strains produced significantly lesser amounts of cellulose at 37°C, pH 8, and in high osmotic conditions as compared to the regular media, at 28°C, and pH 7. Metal biosorption was drastically reduced in these bacteria at 37°C than at 28°C. Only Vitreoscilla sp. ENSG301 and B. thuringiensis ENSW401 completely removed (100%) Cu and Ni at an initial concentration of 12.5 mg l[-1], while all these bacteria totally removed (100%) Pb at concentrations of 12.5 and 25 mg l[-1] at pH 7 and 28°C. At an initial concentration of 100 mg l[-1], the removal of Cu (92.5 to 97.8%) and Pb (89.3 to 98.3%) was the highest at pH 6, while it was higher (84.7 to 93.9%) for Ni at pH 7. Fourier transform infrared spectroscopy results showed metal-unloaded biomass biofilms contained amino, hydroxyl, carboxyl, carbonyl, and phosphate groups. The peak positions of these groups were shifted responding to Cu, Ni, and Pb, suggesting biosorption of metals. Thus, these bacterial strains could be utilized to remove Cu, Ni, and Pb from aquatic environment.}, } @article {pmid34176212, year = {2022}, author = {Toranzo, A and Bustos, PS and Ortega, MG and Páez, PL and Lucero-Estrada, C}, title = {Biologically synthesized silver nanoparticles, mediated by Bothriochloa laguroides, inhibit biofilm formation and eradicate mature biofilm of Yersinia enterocolitica and Staphylococcus aureus.}, journal = {Journal of applied microbiology}, volume = {132}, number = {1}, pages = {209-220}, doi = {10.1111/jam.15195}, pmid = {34176212}, issn = {1365-2672}, support = {PICT-2015-0115//Fondo para la Investigación Científica y Tecnológica/ ; PICT-2015-1558//Fondo para la Investigación Científica y Tecnológica/ ; PICT-2015-1722//Fondo para la Investigación Científica y Tecnológica/ ; PROICO 2-0914//Science and Technology Department, National University of San Luis, Argentina/ ; }, mesh = {Anthocyanins ; *Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Poaceae/*chemistry ; *Silver/pharmacology ; *Staphylococcus aureus/drug effects ; *Yersinia enterocolitica/drug effects ; }, abstract = {AIMS: To phytosynthesize silver nanoparticles (AgNPs) and determine their antibacterial and antibiofilm capacity against gram-positive and gram-negative bacterial strains.

METHODS AND RESULTS: AgNPs were synthesized using Bothriochloa laguroides aqueous extract as reducing and stabilizing agent. After characterization, a phytochemical screening to the extract and the AgNPs was performed. Antibacterial activity, inhibition and eradication of biofilms against Staphylococcus aureus and Yersinia enterocolitica strains were tested. Spherical AgNPs with an average size of 8 nm were obtained. Tannins, flavonoids, carbohydrates, proanthocyanidins, anthocyanins and saponins were identified in aqueous extract; meanwhile, only carbohydrates were identified in AgNPs. The MIC and MBC were determined at pmol L[-1]  levels for all tested strains. Furthermore, AgNPs inhibited more than 90% of biofilms formation and eradicated more than 80% of mature biofilms at concentrations higher than MIC.

CONCLUSIONS: The AgNPs obtained in this study inhibited planktonic and sessile growth, and eradicated mature biofilms of pathogenic bacterial strains at very low concentrations.

The current study showed the promising potential of AgNPs as antibiofilm agents opening the way for the future development of a new class of antibacterial products.}, } @article {pmid34176204, year = {2022}, author = {Jeong, SY and Kim, TG}, title = {Effects of dispersal on species distribution, abundance, diversity and interaction in a bacterial biofilm metacommunity.}, journal = {Journal of applied microbiology}, volume = {132}, number = {1}, pages = {459-469}, doi = {10.1111/jam.15194}, pmid = {34176204}, issn = {1365-2672}, support = {2020R1I1A1A0106554//National Research Foundation of Korea/ ; }, mesh = {Bacteria/genetics ; *Biodiversity ; Biofilms ; *Ecosystem ; }, abstract = {AIMS: Dispersal effects on biofilms have not been adequately studied despite their strong potential impacts on biofilm development. We investigated the effects of dispersal on biofilm metacommunity.

METHODS AND RESULTS: A bacterial consortium was allowed to form biofilms on 12 glass beads attached to disposable plates (compartmentalized or not), and biofilms were scrutinized on days 5, 10 and 15 using quantitative PCR and MiSeq sequencing. Biofilm population density was lesser by 2 orders of magnitude on day 5 when dispersal was allowed (p < 0.05). Then, the population rapidly increased by 4.4 orders with dispersal (p < 0.05) but did not change without dispersal. Community analyses revealed that dispersal increased the species diversity at all sampling times (p < 0.05). Dispersal affected the community structure and increased the homogeneity of local communities (p < 0.05). Distance-decay analysis showed that dispersal reduced the dissimilarity among local communities at all distance levels. Furthermore, dispersal reduced the variability of diversity, population and community structure. Network analysis revealed that dispersal increased the clustering coefficient, network density and connectivity.

CONCLUSIONS: Dispersal increased the species diversity, population and interaction and reduced the variability of the diversity, population and structure among local communities.

Our results suggest that dispersal can induce the niche complementarity and mass effects.}, } @article {pmid34175578, year = {2021}, author = {Yu, T and Ma, M and Sun, Y and Xu, X and Qiu, S and Yin, J and Chen, L}, title = {The effect of sublethal concentrations of benzalkonium chloride on the LuxS/AI-2 quorum sensing system, biofilm formation and motility of Escherichia coli.}, journal = {International journal of food microbiology}, volume = {353}, number = {}, pages = {109313}, doi = {10.1016/j.ijfoodmicro.2021.109313}, pmid = {34175578}, issn = {1879-3460}, mesh = {Bacterial Proteins/genetics/metabolism ; Benzalkonium Compounds/pharmacology ; Biofilms/drug effects ; Carbon-Sulfur Lyases/genetics/metabolism ; *Escherichia coli/drug effects/genetics/metabolism/radiation effects ; Homoserine/analogs & derivatives/genetics/metabolism ; Lactones/metabolism ; *Quorum Sensing/drug effects ; }, abstract = {Escherichia coli can survive improper disinfection processes, which is a potential source of contamination of food products. Benzalkonium chloride (BC) is a common disinfectant widely used in food industry. Bacterial quorum sensing (QS) plays a major role in food spoilage, biofilm formation and food-related pathogenesis. Understanding QS can help to control the growth of undesirable food-related bacteria. The LuxS/AI-2 QS system of E. coli has been confirmed to regulate many important phenotypes including biofilm formation and motility. In the current study, we aimed to investigate the effect of sublethal concentrations of BC on the LuxS/AI-2 system of E. coli isolates from retail meat samples, as well as bacterial biofilm formation and motility. Our results showed that sublethal concentrations of BC promoted AI-2 production in four test E. coli isolates. The results from microplate assay and confocal laser scanning microscopy (CLSM) analysis indicated that sublethal concentrations of BC enhanced biofilm formation of E. coli. When treated with sublethal concentrations of BC, exopolysaccharides (EPS) production during biofilm development increased significantly and swimming motility of tested isolates was also promoted. The expression levels of luxS, biofilm-associated genes and flagellar motility genes were increased by BC at sublethal concentrations. Our findings underline the importance of proper use of the disinfectant BC in food processing environments to control food contamination by E. coli.}, } @article {pmid34174528, year = {2021}, author = {Qi, X and Wang, S and Jiang, Y and Liu, P and Hao, W and Han, J and Zhou, Y and Huang, X and Liang, P}, title = {Additional polypyrrole as conductive medium in artificial electrochemically active biofilm (EAB) to increase the sensitivity of EAB based biosensor in water quality early-warning.}, journal = {Biosensors & bioelectronics}, volume = {190}, number = {}, pages = {113453}, doi = {10.1016/j.bios.2021.113453}, pmid = {34174528}, issn = {1873-4235}, mesh = {Biofilms ; *Biosensing Techniques ; Polymers ; Pyrroles ; Shewanella ; Water Quality ; }, abstract = {Researchers believe that adding conductive mediums in electrochemically active biofilms (EABs) would improve the sensitivity of EAB-based biosensor for real-time water quality early-warning through facilitating the extracellular electron transfer (EET), which has been hardly evidenced mostly because naturally formed EABs employed in previous biosensor studies were recognized distinct and incapable of delivering comparable electrical signals. By preparing artificial EABs where Shewanella oneidensis MR-1 was encapsulated in sodium alginate (SA), this study solved how polypyrrole (PPy) as conductive medium would affect the sensitivity of EAB-based biosensor, as well as mass transfer of toxicant during this process. Different mass ratios (0.125:1, 0.25:1 and 1:1) of PPy over SA were tested, and the sensitivity promoted by 20%, 15% and 6%, respectively. Results indicated that a small amount of PPy addition (PPy: SA = 0.125: 1 in mass ratio) was more effective to increase the biosensor's sensitivity compared to larger amount of PPy employed in EAB. This was when improved conductivity introduced by PPy would dominate in affecting the sensitivity over contrarily weakened mass transfer in the meantime.}, } @article {pmid34174348, year = {2021}, author = {Vertuan, M and Machado, PF and de Souza, BM and Braga, AS and Magalhães, AC}, title = {Effect of TiF4/NaF and chitosan solutions on the development of enamel caries under a microcosm biofilm model.}, journal = {Journal of dentistry}, volume = {111}, number = {}, pages = {103732}, doi = {10.1016/j.jdent.2021.103732}, pmid = {34174348}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cariostatic Agents/therapeutic use ; Cattle ; *Chitosan/pharmacology ; *Dental Caries/prevention & control ; Dental Caries Susceptibility ; Fluorides/pharmacology/therapeutic use ; Humans ; Sodium Fluoride/pharmacology/therapeutic use ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVES: To evaluate the effect of experimental solutions containing TiF4/NaF and chitosan on bacterial species and on enamel caries prevention.

METHODS: Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel for five days, under 5% CO2 and 37 °C. From the second day until the end, the treatments were applied (1 × 60 s/day): (1) NaF (500 ppm F[-], positive control); (2) TiF4 and NaF (TiF4: 190 ppm Ti[4+] and 300 ppm F[-]; NaF: 190 ppm F[-]); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPas, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPas, 75% deacetylation). CFU counting was performed for total microorganism, total streptococcus, total lactobacillus and Streptococcus mutans. Enamel demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < .050).

RESULTS: No differences were found between the treatments with respect to CFU counting (ANOVA, p > .050). Enamel treated with TiF4/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF4/NaF and NaF solutions, being all of them able to significantly reduce mineral loss (50-74%), but only TiF4/NaF plus chitosan reduced lesion depth (55%) compared to the negative control (p = .001).

CONCLUSION: TiF4/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development in 79% compared to control under this model.

CLINICAL SIGNIFICANCE: This study showed that TiF4/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development under a microcosm biofilm model.}, } @article {pmid34173930, year = {2021}, author = {Alvares, JJ and Furtado, IJ}, title = {Anti-Pseudomonas aeruginosa biofilm activity of tellurium nanorods biosynthesized by cell lysate of Haloferax alexandrinus GUSF-1(KF796625).}, journal = {Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine}, volume = {34}, number = {5}, pages = {1007-1016}, pmid = {34173930}, issn = {1572-8773}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Haloferax ; Humans ; *Nanotubes ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; Tellurium/pharmacology ; }, abstract = {Pseudomonas aeruginosa, an opportunistic human pathogen, is a major health concern as it grows as a biofilm and evades the host's immune defenses. Formation of biofilms on catheter and endotracheal tubes demands the development of biofilm-preventive (anti-biofilm) approaches and evaluation of nanomaterials as alternatives to antibiotics. The present study reports the successful biosynthesis of tellurium nanorods using cell lysate of Haloferax alexandrinus GUSF-1 (KF796625). The black particulate matter had absorption bands at 0.5 and 3.6 keV suggestive of elemental tellurium; showed x-ray diffraction peaks at 2θ values 24.50°, 28.74°, 38.99°, 43.13°, 50.23° and displayed a crystallite size of 36.99 nm. The black nanorods of tellurium were an average size of 40 nm × 7 nm, as observed in transmission electron microscopy. To our knowledge, the use of cell lysate of Haloferax alexandrinus GUSF-1 (KF796625) as a green route for the biosynthesis of tellurium nanorods with a Pseudomonas aeruginosa biofilm inhibiting capacity is novel to haloarchaea. At 50 µg mL[-1], these tellurium nanorods exhibited 75.03% in-vitro reduction of biofilms of Pseudomonas aeruginosa ATCC 9027, comparable to that of ciprofloxacin, which is used in treatment of Pseudomonas infections. Further, the observed ability of these nanoparticles to inhibit the formation of Pseudomonas biofilms is worthy of future research perusal.}, } @article {pmid34173213, year = {2022}, author = {Salisbury, AM and Mullin, M and Chen, R and Percival, SL}, title = {Antibiofilm Efficacy of Polihexanide, Octenidine and Sodium Hypochlorite/Hypochlorous Acid Based Wound Irrigation Solutions against Staphylococcus aureus, Pseudomonas aeruginosa and a Multispecies Biofilm.}, journal = {Advances in experimental medicine and biology}, volume = {1369}, number = {}, pages = {53-67}, pmid = {34173213}, issn = {0065-2598}, mesh = {Biguanides ; Biofilms ; Humans ; Hypochlorous Acid ; Imines ; Pseudomonas aeruginosa ; Pyridines ; Sodium Hypochlorite/pharmacology ; *Staphylococcal Infections/drug therapy/prevention & control ; *Staphylococcus aureus ; Water ; }, abstract = {Infection and the formation of biofilms have been shown to have a significant role in increased inflammation and delayed wound healing. Wound irrigation solutions are used to debride wounds, removing cell debris and infecting microorganisms, therefore preventing infection. The aim of this study was to evaluate a Polihexanide (PHMB) based wound irrigation solution, Octenidine HCl based wound irrigation solution and electrolysed water based wound care solution for antibiofilm efficacy against Staphylococcus aureus, Pseudomonas aeruginosa and a multispecies biofilm in several models to gain a broad understanding of ability. The PHMB based wound irrigation solution demonstrated broad range antibiofilm efficacy against P. aeruginosa, S. aureus and the multispecies biofilm. The Octenidine HCl based wound irrigation solution and the electrolysed water based wound care solution demonstrated potent antibiofilm efficacy against S. aureus and to a lesser extent P. aeruginosa. Overall, less efficacy was observed in the drip flow bioreactor model for all 3 test solutions, which may be attributed to the continuous flow of nutrients during treatment, which may have diluted or washed away the solution. The data presented also highlights the importance of testing antibiofilm activity in a range of biofilm models and against different bacterial strains to get an overall representation of efficacy.}, } @article {pmid34173207, year = {2021}, author = {Lee, JS and Park, SW and Lee, HB and Kang, SS}, title = {Bacteriocin-Like Inhibitory Substance (BLIS) Activity of Enterococcus faecium DB1 Against Biofilm Formation by Clostridium perfringens.}, journal = {Probiotics and antimicrobial proteins}, volume = {13}, number = {5}, pages = {1452-1457}, pmid = {34173207}, issn = {1867-1314}, mesh = {*Bacteriocins/pharmacology ; Biofilms/*drug effects ; Clostridium perfringens/*drug effects/growth & development ; *Enterococcus faecium ; }, abstract = {The antibiofilm effect of bacteriocin-like inhibitory substance (BLIS) from Enterococcus faecium DB1 against Clostridium perfringens was investigated in the present study. BLIS of E. faecium DB1 significantly reduced biofilm formation by C. perfringens in a dose-dependent manner for 24 and 48 h. In particular, treatment with BLIS of E. faecium DB1 significantly inhibited biofilm formation by C. perfringens on chicken meat and stainless steel coupon surfaces. Moreover, BLIS of E. faecium DB1 decreased the viability of C. perfringens biofilm and planktonic cells, indicating that the reduction of biofilm formation by C. perfringens might be achieved by killing the bacterial cells. Taken together, the present results suggest that BLIS of E. faecium DB1 can be a promising antibiofilm agent to eradicate C. perfringens.}, } @article {pmid34170482, year = {2021}, author = {Aguayo-Acosta, A and Franco-Frías, E and Heredia, N and Merino-Mascorro, JA and Dávila-Aviña, JE and Vidal, JE and García, S}, title = {Epigallocatechin gallate and Lactobacillus plantarum culture supernatants exert bactericidal activity and reduce biofilm formation in Clostridium perfringens.}, journal = {Folia microbiologica}, volume = {66}, number = {5}, pages = {843-853}, pmid = {34170482}, issn = {1874-9356}, mesh = {Biofilms ; Catechin/*analogs & derivatives/pharmacology ; *Clostridium perfringens/drug effects/genetics ; *Culture Media, Conditioned/pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; *Lactobacillus plantarum/metabolism ; }, abstract = {Clostridium perfringens forms biofilms and spores that are a source of food contamination. In this study, the antibacterial activities of Lactobacillus plantarum culture supernatants (LP-S), LP-S fractions, and the plant-derived compound epigallocatechin gallate (EG) were evaluated. Specifically, their effects on the viability and biofilm-forming ability of C. perfringens were assessed. Moreover, the expression of quorum sensing-regulated genes associated with the pathogenesis of this microorganism and that of genes involved in biofilm formation was also investigated. The results showed that both EG and the LP-S exerted bactericidal activity against all C. perfringens strains tested. The minimal bactericidal concentration (MBC) of EG was 75 µg/mL for all strains but ranged from 61 to 121 µg of total protein per mL for LP-S. EG exerted only minor effects on biofilm formation, whereas LP-S, particularly its 10 and 30 K fractions, significantly reduced the biofilm-forming ability of all the strains. The antibiofilm activity of LP-S was lost following preincubation with proteases, suggesting that it was mediated by a proteinaceous molecule. The treatment of C. perfringens with either EG or LP-S did not change the transcript levels of two CpAL (C. perfringens quorum-sensing Agr-like system)-related genes, agrB and agrD, which are known to be involved in the regulation of biofilms, suggesting that LP-S exerted its biofilm inhibitory activity downstream of CpAL signaling. In summary, we demonstrated the bactericidal activity of EG and LP-S against C. perfringens and antibiofilm activity of LP-S at a subinhibitory dose. Our results suggested that these compounds can be further explored for food safety applications to control agents such as C. perfringens.}, } @article {pmid34170406, year = {2021}, author = {Li, E and Wu, J and Zhang, D}, title = {Exogenous autoinducer-2 inhibits biofilm development of Desulfovibrio sp. Huiquan2017.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {7}, pages = {124}, pmid = {34170406}, issn = {1573-0972}, support = {51771180//National Natural Science Foundation of China/ ; 41806087//National Natural Science Foundation of China/ ; U1906226//National Natural Science Foundation of China/ ; COMS2019Q13//Key Deployment Project of Center for Ocean Mega-Research of Science, Chinese Academy of Sciences/ ; 2019YFE012026//Key Projects of China National Key Research and Development Plan/ ; }, mesh = {Agrobacterium tumefaciens/metabolism ; Bacterial Proteins/metabolism/pharmacology ; Biofilms/*drug effects/*growth & development ; Corrosion ; Desulfovibrio/*drug effects/*growth & development/*metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Homoserine/*analogs & derivatives/metabolism/pharmacology ; Lactones/*metabolism/*pharmacology ; Quorum Sensing ; Vibrio/metabolism ; }, abstract = {Sulfate-reducing bacteria (SRB) are culprits for microbiologically influenced corrosion, and biofilms are believed to play essential roles in the corrosion induced by SRB. However, little is known about the regulation of SRB biofilms. Quorum sensing signal molecules acyl-homoserine lactones (AHLs) and autoinducer-2 (AI-2) regulate biofilm formation of many bacteria. In this study, the production of AHLs and AI-2 by one SRB strain, Desulfovibrio sp. Huiquan2017, was detected, and the effect of exogenous AI-2 on bacterial biofilm formation was discussed. It was found that the cell-free supernatants of Desulfovibrio sp. Huiquan2017 induced luminescence in a ∆luxS mutant strain Vibrio harveyi BB170, indicating the production of functional AI-2 by the bacterium. In the presence of exogenous AI-2, the growth of Desulfovibrio sp. Huiquan2017 and early biofilm formation were not affected, but the later stage of biofilm development was inhibited significantly. The biofilms became looser, smaller, and thinner, and contained less bacteria and extracellular polymeric substances (EPS). The inhibition effect of AI-2 on the biofilm development of Desulfovibrio sp. Huiquan2017 was mainly achieved through reducing the amount of EPS in biofilms. These findings shed light on the biofilm regulation of SRB.}, } @article {pmid34168627, year = {2021}, author = {Calero Preciado, C and Boxall, J and Soria-Carrasco, V and Martínez, S and Douterelo, I}, title = {Implications of Climate Change: How Does Increased Water Temperature Influence Biofilm and Water Quality of Chlorinated Drinking Water Distribution Systems?.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {658927}, pmid = {34168627}, issn = {1664-302X}, abstract = {Temperature variation can promote physico-chemical and microbial changes in the water transported through distribution systems and influence the dynamics of biofilms attached to pipes, thus contributing to the release of pathogens into the bulk drinking water. An experimental real-scale chlorinated DWDS was used to study the effect of increasing temperature from 16 to 24°C on specific pathogens, bacterial-fungal communities (biofilm and water samples) and determine the risk of material accumulation and mobilisation from the pipes into the bulk water. Biofilm was developed for 30 days at both temperatures in the pipe walls, and after this growth phase, a flushing was performed applying 4 gradual steps by increasing the shear stress. The fungal-bacterial community characterised by Illumina MiSeq sequencing, and specific pathogens were studied using qPCR: Mycobacterium spp., Mycobacterium avium complex, Acanthamoeba spp., Pseudomonas aeruginosa, Legionella pneumophilia, and Stenotrophomonas maltophilia. Sequencing data showed that temperature variation significantly modified the structure of biofilm microbial communities from the early stages of biofilm development. Regarding bacteria, Pseudomonas increased its relative abundance in biofilms developed at 24°C, while fungal communities showed loss of diversity and richness, and the increase in dominance of Fusarium genus. After the mobilisation phase, Pseudomonas continued being the most abundant genus at 24°C, followed by Sphingobium and Sphingomonas. For biofilm fungal communities after the mobilisation phase, Helotiales incertae sedis and Fusarium were the most abundant taxa. Results from qPCR showed a higher relative abundance of Mycobacterium spp. on day 30 and M. avium complex throughout the growth phase within the biofilms at higher temperatures. The temperature impacts were not only microbial, with physical mobilisation showing higher discolouration response and metals release due to the increased temperature. While material accumulation was accelerated by temperature, it was not preferentially to either stronger or weaker biofilm layers, as turbidity results during the flushing steps showed. This research yields new understanding on microbial challenges that chlorinated DWDS will undergo as global temperature rises, this information is needed in order to protect drinking water quality and safety while travelling through distribution systems.}, } @article {pmid34168199, year = {2021}, author = {Rosman, CWK and van der Mei, HC and Sjollema, J}, title = {Influence of sub-inhibitory concentrations of antimicrobials on micrococcal nuclease and biofilm formation in Staphylococcus aureus.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {13241}, pmid = {34168199}, issn = {2045-2322}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/pharmacology ; Doxycycline/pharmacology ; Erythromycin/pharmacology ; Gentamicins/pharmacology ; Micrococcal Nuclease/*drug effects/metabolism ; Polysaccharides, Bacterial/metabolism ; Resveratrol/pharmacology ; Staphylococcus aureus/*drug effects/enzymology/growth & development ; Stem Cells/drug effects ; Vancomycin/pharmacology ; }, abstract = {A major contributor to biomaterial associated infection (BAI) is Staphylococcus aureus. This pathogen produces a protective biofilm, making eradication difficult. Biofilms are composed of bacteria encapsulated in a matrix of extracellular polymeric substances (EPS) comprising polysaccharides, proteins and extracellular DNA (eDNA). S. aureus also produces micrococcal nuclease (MN), an endonuclease which contributes to biofilm composition and dispersion, mainly expressed by nuc1. MN expression can be modulated by sub-minimum inhibitory concentrations of antimicrobials. We investigated the relation between the biofilm and MN expression and the impact of the application of antimicrobial pressure on this relation. Planktonic and biofilm cultures of three S. aureus strains, including a nuc1 deficient strain, were cultured under antimicrobial pressure. Results do not confirm earlier findings that MN directly influences total biomass of the biofilm but indicated that nuc1 deletion stimulates the polysaccharide production per CFU in the biofilm in in vitro biofilms. Though antimicrobial pressure of certain antibiotics resulted in significantly increased quantities of polysaccharides per CFU, this did not coincide with significantly reduced MN activity. Erythromycin and resveratrol significantly reduced MN production per CFU but did not affect total biomass or biomass/CFU. Reduction of MN production may assist in the eradication of biofilms by the host immune system in clinical situations.}, } @article {pmid34168081, year = {2021}, author = {Webster, SS and Lee, CK and Schmidt, WC and Wong, GCL and O'Toole, GA}, title = {Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {118}, number = {26}, pages = {}, pmid = {34168081}, issn = {1091-6490}, support = {P20 GM113132/GM/NIGMS NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; R01 AI083256/AI/NIAID NIH HHS/United States ; R37 AI083256/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Motifs ; Biofilms/*growth & development ; Conserved Sequence ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/chemistry/genetics/*metabolism ; Fimbriae, Bacterial/*metabolism ; Models, Biological ; Mutation/genetics ; Phosphorus-Oxygen Lyases/chemistry/genetics/*metabolism ; Protein Binding ; Protein Domains ; Pseudomonas aeruginosa/*enzymology/*physiology ; Signal Transduction ; Single-Cell Analysis ; Type IV Secretion Systems ; }, abstract = {To initiate biofilm formation, it is critical for bacteria to sense a surface and respond precisely to activate downstream components of the biofilm program. Type 4 pili (T4P) and increasing levels of c-di-GMP have been shown to be important for surface sensing and biofilm formation, respectively; however, mechanisms important in modulating the levels of this dinucleotide molecule to define a precise output response are unknown. Here, using macroscopic bulk assays and single-cell tracking analyses of Pseudomonas aeruginosa, we uncover a role of the T4P alignment complex protein, PilO, in modulating the activity of the diguanylate cyclase (DGC) SadC. Two-hybrid and bimolecular fluorescence complementation assays, combined with genetic studies, are consistent with a model whereby PilO interacts with SadC and that the PilO-SadC interaction inhibits SadC's activity, resulting in decreased biofilm formation and increased motility. Using single-cell tracking, we monitor both the mean c-di-GMP and the variance of this dinucleotide in individual cells. Mutations that increase PilO-SadC interaction modestly, but significantly, decrease both the average and variance in c-di-GMP levels on a cell-by-cell basis, while mutants that disrupt PilO-SadC interaction increase the mean and variance of c-di-GMP levels. This work is consistent with a model wherein P. aeruginosa uses a component of the T4P scaffold to fine-tune the levels of this dinucleotide signal during surface commitment. Finally, given our previous findings linking SadC to the flagellar machinery, we propose that this DGC acts as a bridge to integrate T4P and flagellar-derived input signals during initial surface engagement.}, } @article {pmid34167627, year = {2021}, author = {Xiang, S and Fan, Z and Sun, D and Zhu, T and Ming, J and Chen, X}, title = {Near-Infrared Light Enhanced Peroxidase-Like Activity of PEGylated Palladium Nanozyme for Highly Efficient Biofilm Eradication.}, journal = {Journal of biomedical nanotechnology}, volume = {17}, number = {6}, pages = {1131-1147}, doi = {10.1166/jbn.2021.3095}, pmid = {34167627}, issn = {1550-7033}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Hydrogen Peroxide ; *Palladium/pharmacology ; *Peroxidase ; Polyethylene Glycols ; }, abstract = {The overall eradication of biofilm-mode growing bacteria holds significant key to the answer of a series of infection-related health problems. However, the extracellular matrix of bacteria biofilms disables the traditional antimicrobials and, more unfortunately, hampers the development of the anti-infectious alternatives. Therefore, highly effective antimicrobial agents are an urgent need for biofilm-infection control. Herein, a PEGylated palladium nanozyme (Pd-PEG) with peroxidase (POD)-like activity for highly efficient biofilm infection control is reported. Pd-PEG also shows the intrinsic photothermal effect as well as near-infrared (NIR) light-enhanced POD-like activity in the acidic environment, thereby massively destroying the biofilm matrix and killing the adhering bacteria. Importantly, the antimicrobial mechanism of the synergistic treatment based on Pd-PEG+H2O2+NIR combination was disclosed. In vitro and in vivo results illustrated the designed Pd-PEG+H2O2 +NIR treatment reagent possessed outstanding antibacterial and biofilms elimination effects with negligible biotoxicity. This work hopefully facilitates the development of metal-based nanozymes in biofilm related infectious diseases.}, } @article {pmid34164821, year = {2021}, author = {Silva, PAO and Lima, SMF and Martins, DCM and Amorim, IA and Lacorte, C and de Almeida, JA and Franco, OL and Rezende, TMB}, title = {Concentrated MTA Repair HP reduced biofilm and can cause reparative action at a distance.}, journal = {International endodontic journal}, volume = {54}, number = {10}, pages = {1925-1936}, doi = {10.1111/iej.13592}, pmid = {34164821}, issn = {1365-2591}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT)./ ; 0193.001702/2017//Fundação de Apoio à Pesquisa do Distrito Federal/ ; 409196/2018-5//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Aluminum Compounds ; Biofilms ; *Calcium Compounds/pharmacology ; Cells, Cultured ; Dental Pulp ; Drug Combinations ; Materials Testing ; Oxides/pharmacology ; *Root Canal Filling Materials ; Silicates/pharmacology ; }, abstract = {AIM: To evaluate in vitro whether MTA Repair HP can induce repair processes at a distance, including its effects on biofilm, cell viability, migration, production of TGF-β, phosphate and ALP, evaluated through MTA diluted extracts.

METHODOLOGY: Initially, antibacterial tests were performed with the bacterium Streptococcus mutans (ATCC 25175) in the presence of MTA extracts (dilutions of 1:1, 1:2 and 1:4). Growth inhibition assay by microdilution in broth, antibiofilm plate assay of young biofilm and antibiofilm assay in confocal microscopy of mature biofilm were carried out. Then, pulp cells were stimulated in the presence of several MTA dilutions, and cell viability (MTT assay), proliferation and migration capacity (scratch assay) were evaluated. To evaluate the capacity of 1:1, 1:2 and 1:4 dilutions of MTA Repair HP to promote the production of important agents of odontogenic differentiation and mineralization, ALP activity, TGF-β secretion and phosphate quantification were measured. Statistical differences were verified using one-way and two-way anova and Tukey's post-tests.

RESULTS: The test dilutions of MTA Repair HP did not inhibit planktonic S. mutans growth but were able to reduce young and mature S. mutans biofilm (p < 0.001). In addition, none of the MTA Repair HP dilutions was cytotoxic for pulp cells. The 1:2 and 1:4 dilutions of MTA Repair HP induced migration and proliferation of pulp cells (p < 0.05). ALP activity and TGF-β secretion were independent of the tested dilution (p < 0.001). Diluted 1:4 MTA Repair HP produced less phosphate than the more concentrated 1:1 and 1:2 MTA dilutions (p < 0.001).

CONCLUSIONS: Undiluted MTA Repair HP reduced S. mutans biofilm, when compared to 1:2 and 1:4 MTA dilutions. Furthermore, none of the tested dilutions was cytotoxic to pulp cells. MTA Repair HP promoted cell migration and proliferation at a distance, assessed through the dilution of the MTA. Even from a distance, MTA Repair HP has the ability to participate in some events related to repair, such as migration, proliferation and TGF production.}, } @article {pmid34163871, year = {2020}, author = {Ran, B and Yuan, Y and Xia, W and Li, M and Yao, Q and Wang, Z and Wang, L and Li, X and Xu, Y and Peng, X}, title = {A photo-sensitizable phage for multidrug-resistant Acinetobacter baumannii therapy and biofilm ablation.}, journal = {Chemical science}, volume = {12}, number = {3}, pages = {1054-1061}, pmid = {34163871}, issn = {2041-6520}, abstract = {Antibiotic abuse causes the emergence of bacterial resistance. Photodynamic antibacterial chemotherapy (PACT) has great potential to solve serious bacterial resistance, but it suffers from the inefficient generation of ROS and the lack of bacterial targeting ability. Herein, a unique cationic photosensitizer (NB) and bacteriophage (ABP)-based photodynamic antimicrobial agent (APNB) is developed for precise bacterial eradication and efficient biofilm ablation. Thanks to the structural modification of the NB photosensitizer with a sulfur atom, it displays excellent reactive oxygen species (ROS)-production ability. Moreover, specific binding to pathogenic microorganisms can be provided by bacteriophages. The developed APNB has multiple functions, including bacteria targeting, near-infrared fluorescence imaging and combination therapy (PACT and phage therapy). Both in vitro and in vivo experiments prove that APNB can efficiently treat A. baumannii infection. Particularly, the recovery from A. baumannii infection after APNB treatment is faster than that with ampicillin and polymyxin B in vivo. Furthermore, the strategy of combining bacteriophages and photosensitizers is employed to eradicate bacterial biofilms for the first time, and it shows the excellent biofilm ablation effect as expected. Thus, APNB has huge potential in fighting against multidrug-resistant bacteria and biofilm ablation in practice.}, } @article {pmid34163443, year = {2021}, author = {Lawal, OU and Barata, M and Fraqueza, MJ and Worning, P and Bartels, MD and Goncalves, L and Paixão, P and Goncalves, E and Toscano, C and Empel, J and Urbaś, M and Domiìnguez, MA and Westh, H and de Lencastre, H and Miragaia, M}, title = {Staphylococcus saprophyticus From Clinical and Environmental Origins Have Distinct Biofilm Composition.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {663768}, pmid = {34163443}, issn = {1664-302X}, abstract = {Biofilm formation has been shown to be critical to the success of uropathogens. Although Staphylococcus saprophyticus is a common cause of urinary tract infections, its biofilm production capacity, composition, genetic basis, and origin are poorly understood. We investigated biofilm formation in a large and diverse collection of S. saprophyticus (n = 422). Biofilm matrix composition was assessed in representative strains (n = 63) belonging to two main S. saprophyticus lineages (G and S) recovered from human infection, colonization, and food-related environment using biofilm detachment approach. To identify factors that could be associated with biofilm formation and structure variation, we used a pangenome-wide association study approach. Almost all the isolates (91%; n = 384/422) produced biofilm. Among the 63 representative strains, we identified eight biofilm matrix phenotypes, but the most common were composed of protein or protein-extracellular DNA (eDNA)-polysaccharides (38%, 24/63 each). Biofilms containing protein-eDNA-polysaccharides were linked to lineage G and environmental isolates, whereas protein-based biofilms were produced by lineage S and infection isolates (p < 0.05). Putative biofilm-associated genes, namely, aas, atl, ebpS, uafA, sasF, sasD, sdrH, splE, sdrE, sdrC, sraP, and ica genes, were found with different frequencies (3-100%), but there was no correlation between their presence and biofilm production or matrix types. Notably, icaC_1 was ubiquitous in the collection, while icaR was lineage G-associated, and only four strains carried a complete ica gene cluster (icaADBCR) except one that was without icaR. We provided evidence, using a comparative genomic approach, that the complete icaADBCR cluster was acquired multiple times by S. saprophyticus and originated from other coagulase-negative staphylococci. Overall, the composition of S. saprophyticus biofilms was distinct in environmental and clinical isolates, suggesting that modulation of biofilm structure could be a key step in the pathogenicity of these bacteria. Moreover, biofilm production in S. saprophyticus is ica-independent, and the complete icaADBCR was acquired from other staphylococci.}, } @article {pmid34163189, year = {2021}, author = {Hao, Z and Guo, Y and Rao, L and Yu, J and Zhan, Q and Xu, Y and Wang, B and Wu, X and Yu, F}, title = {Deletion of SarX Decreases Biofilm Formation of Staphylococcus aureus in a Polysaccharide Intercellular Adhesin (PIA)-Dependent Manner by Downregulating spa.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {2241-2250}, pmid = {34163189}, issn = {1178-6973}, abstract = {INTRODUCTION: Biofilm formation by Staphylococcus aureus is an important virulence determinant mediated by the polysaccharide intercellular adhesin (PIA) encoded by the ica operon or mediated by surface and extracellular proteins. SarX is a 250-residue two-domain SarA homolog that activates spa transcription. Previous studies demonstrated that Staphylococcus epidermidis SarX protein regulated the transcriptional activity of the agr and ica loci and controlled the biofilm phenotype, primarily by regulating icaADBC transcription and PIA production.

RESULTS: In this study, biofilm formation and detachment of the clinical isolate S. aureus SA75 were significantly decreased in the sarX mutant strain. The effect of sarX mutation on S. aureus biofilm formation was related to the production of PIA and not to that of eDNA. Deletion of sarX was associated with a 1.8-fold reduction in spa transcription as determined by RT-PCR analysis, and this reduction could be restored by chromosomal complementation of sarX. Expression of Spa protein was also decreased in the S. aureus sarX mutant.

CONCLUSION: sarX promoted biofilm production of S. aureus that may primarily be mediated through increasing ica operon expression and PIA production. Furthermore, deletion of sarX reduced S. aureus biofilm formation by downregulating spa.}, } @article {pmid34163185, year = {2021}, author = {Pandey, R and Mishra, SK and Shrestha, A}, title = {Characterisation of ESKAPE Pathogens with Special Reference to Multidrug Resistance and Biofilm Production in a Nepalese Hospital.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {2201-2212}, pmid = {34163185}, issn = {1178-6973}, abstract = {BACKGROUND: "ESKAPE" is an acronym for a group of life-threatening nosocomial pathogens, viz, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. Global efforts on controlling multidrug-resistant (MDR) organisms have been hampered by their ability to escape antibacterial drugs. This study was undertaken to determine the prevalence of ESKAPE pathogens with prime focus on biofilm production and antibiotic resistance.

METHODS: A total of 8756 clinical samples were processed for the isolation and identification of ESKAPE pathogens following standard microbiological procedures. These isolates were subjected to antimicrobial sensitivity test as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Test for MDR, extended-spectrum β-lactamase (ESBL), metallo-β-lactamase (MBL), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) was done by the disk diffusion and E-test methods. In the case of VRE molecular detection was done for vanA and vanB genes. All the isolates were processed for biofilm detection by the tube adherence method.

RESULTS: The percentage distribution of Enterococcus faecium was 5.5%, S. aureus 33.4%, K. pneumoniae 33.0%, A. baumannii 8.6%, P. aeruginosa 18.6%, and Enterobacter aerogenes 0.9%. MRSA was 57.6%, and vancomycin resistance among Enterococcus faecium was 20%. ESBL- and MBL-producing K. pneumoniae were 16.1%, and 8.1%, A. baumannii 10.3% each and P. aeruginosa 10.7% and 8.3%, respectively. A total of 42.3% of isolates were biofilm producers. Linezolid was the drug of choice for VRE. Ampicillin-sulbactam was most useful against A. baumannii apart from polymyxins, whereas piperacillin-tazobactam was effective against other Gram-negative bacteria. VanA gene was detected in all the VRE isolates.

CONCLUSION: This study estimates the burden of the ESKAPE organisms and their antimicrobial resistance pattern in a hospital setting. A high percentage of drug resistance and biofilm production was noted; hence antimicrobial resistance surveillance targeting ESKAPE pathogens should be incorporated in the infection control policy in Nepal.}, } @article {pmid34160701, year = {2022}, author = {Baldino, MEL and Medina-Silva, R and Sumienski, J and Figueiredo, MA and Salum, FG and Cherubini, K}, title = {Nystatin effect on chlorhexidine efficacy against Streptococcus mutans as planktonic cells and mixed biofilm with Candida albicans.}, journal = {Clinical oral investigations}, volume = {26}, number = {1}, pages = {633-642}, pmid = {34160701}, issn = {1436-3771}, mesh = {Biofilms ; *Candida albicans ; Chlorhexidine/pharmacology ; Humans ; Microbial Sensitivity Tests ; Nystatin/pharmacology ; Plankton ; *Streptococcus mutans ; }, abstract = {OBJECTIVE: The aim of this study was to evaluate the effect of nystatin on the efficacy of chlorhexidine against Streptococcus mutans in planktonic cells and mixed biofilm with Candida albicans.

MATERIAL AND METHODS: S. mutans ATCC 25,175 in suspension and also combined with C. albicans ATCC 18,804 in biofilm were cultured. Minimum inhibitory concentration (MIC), crystal violet colorimetric assay, and colony-forming unit counting (CFUs/mL) were performed.

RESULTS: An increased MIC of chlorhexidine against S. mutans was observed when the drugs were administered mixed in a single formulation and with time intervals in between, except for the 30-min interval. The biofilm optical density (OD) in treatments using chlorhexidine and nystatin combined did not significantly differ from chlorhexidine alone. Either in biofilm colorimetric assay or determination of CFUs, the combined treatments with nystatin administered before chlorhexidine had less effect on chlorhexidine efficacy.

CONCLUSIONS: Nystatin interferes with the action of chlorhexidine against S. mutans. The antimicrobial effectiveness of the combined drugs depends on their concentration, time interval used, and the planktonic or biofilm behavior of the microorganisms.

CLINICAL RELEVANCE: In view of the great number of patients that can receive a prescription of chlorhexidine and nystatin concomitantly, this study contributes to the knowledge about the effect of the combined drugs. Given the high prevalence of prescriptions of chlorhexidine and nystatin in dentistry, dental professionals should be aware of their possible antagonistic effect.}, } @article {pmid34159499, year = {2021}, author = {Zhang, S and Zhong, Q and Jiang, Y and Li, M and Xia, S}, title = {Temperature-induced difference in microbial characterizations accounts for the fluctuation of sequencing batch biofilm reactor performance.}, journal = {Biodegradation}, volume = {32}, number = {5}, pages = {595-610}, pmid = {34159499}, issn = {1572-9729}, mesh = {Biodegradation, Environmental ; *Biofilms ; *Bioreactors ; Temperature ; Wastewater ; }, abstract = {Generally, the purification performance of bioreactors could be influenced by temperature variation via shaping different microbial communities. However, the underlying mechanisms remain largely unknown. Here, the variation trends of microbial communities in three sequencing batch biofilm reactors (SBBRs) under four different temperatures (15, 20, 25, 30 °C) were compared. It was found that temperature increment led to an obvious enhancement in nutrient removal which was mainly occurred in the aerobic section. Meanwhile, distinct differences in dominant microbial communities or autotrophic nitrifiers were also observed. The performance of the SBBR reactors was closely associated with nitrifier communities since the treated wastewater was characterized by a severe lack of carbon sources (mean effluent COD ≤ 14.4 mg/L). Spearman correlation unraveled that: most of the differentiated microbes as well as the dominant potential functions were strongly associated with nutrient removal, indicating the temperature-induced difference in microbial community well explained the distinction in purification performance.}, } @article {pmid34159252, year = {2021}, author = {Albano, M and Greenwood-Quaintance, KE and Karau, MJ and Mandrekar, JN and Patel, R}, title = {Anti-biofilm activity of antibiotic-loaded Hylomate®.}, journal = {International journal of cardiology. Heart & vasculature}, volume = {34}, number = {}, pages = {100801}, pmid = {34159252}, issn = {2352-9067}, abstract = {INTRODUCTION: Antibiotic envelopes are being developed for cardiac implantable electronic device (CIED) wrapping to reduce the risk of infections.

METHODS: Fifteen CIED infection-associated bacterial isolates of Staphylococcus aureus, Staphylococcus epidermidis and Cutibacterium acnes were used to assess in vitro biofilm formation on Hylomate® compared to titanium, silicone and polyurethane coupons pre-treated with vancomycin (400 µg/ml), bacitracin (1000 U/ml) or a combination of rifampin (80 µg/ml) plus minocycline (50 µg/ml). Scanning electron microscopy (SEM) was performed to visualize bacteria on Hylomate®.

RESULTS: There was significantly less (p < 0.05) S. aureus and S. epidermidis on Hylomate® pre-treated with vancomycin, bacitracin or rifampin plus minocycline after 24 h of incubation (≤1.00 log10 CFU/cm[2]) compared with titanium, silicone or polyurethane pre-treated with vancomycin, bacitracin or rifampin plus minocycline. C. acnes biofilms were not detected (≤1.00 log10 CFU/cm[2]) on pre-treated Hylomate® coupons.

CONCLUSIONS: This study showed that Hylomate® coupons pre-treated with antibiotics reduced staphylococcal and C. acnes biofilm formation in vitro.}, } @article {pmid34157481, year = {2021}, author = {Raas, MWD and Silva, TP and Freitas, JCO and Campos, LM and Fabri, RL and Melo, RCN}, title = {Whole slide imaging is a high-throughput method to assess Candida biofilm formation.}, journal = {Microbiological research}, volume = {250}, number = {}, pages = {126806}, doi = {10.1016/j.micres.2021.126806}, pmid = {34157481}, issn = {1618-0623}, mesh = {Biofilms/*growth & development ; Candida/classification/growth & development/*physiology/ultrastructure ; Candida albicans/growth & development/ultrastructure ; Candida glabrata/growth & development/ultrastructure ; Candida tropicalis/growth & development/ultrastructure ; High-Throughput Screening Assays/*methods ; Microscopy, Electron, Scanning/*methods ; Optical Imaging/*methods ; }, abstract = {New strategies that enable fast and accurate visualization of Candida biofilms are necessary to better study their structure and response to antifungals agents. Here, we applied whole slide imaging (WSI) to study biofilm formation of Candida species. Three relevant biofilm-forming Candida species (C. albicans ATCC 10231, C. glabrata ATCC 2001, and C. tropicalis ATCC 750) were cultivated on glass coverslips both in presence and absence of widely used antifungals. Accumulated biofilms were stained with fluorescent markers and scanned in both bright-field and fluorescence modes using a WSI digital scanner. WSI enabled clear assessment of both size and structural features of Candida biofilms. Quantitative analyses readily detected reductions in biofilm-covered surface area upon antifungal exposure. Furthermore, we show that the overall biofilm growth can be adequately assessed across both bright-field and fluorescence modes. At the single-cell level, WSI proved adequate, as morphometric parameters evaluated with WSI did not differ significantly from those obtained with scanning electron microscopy, considered as golden standard at single-cell resolution. Thus, WSI allows for reliable visualization of Candida biofilms enabling both large-scale growth assessment and morphometric characterization of single-cell features, making it an important addition to the available microscopic toolset to image and analyse fungal biofilm growth.}, } @article {pmid34157434, year = {2021}, author = {He, X and Zhang, S and Jiang, Y and Li, M and Yuan, J and Wang, G}, title = {Influence mechanism of filling ratio on solid-phase denitrification with polycaprolactone as biofilm carrier.}, journal = {Bioresource technology}, volume = {337}, number = {}, pages = {125401}, doi = {10.1016/j.biortech.2021.125401}, pmid = {34157434}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrates ; *Polyesters ; }, abstract = {In this study, three up-flow fixed-bed bioreactors were constructed with three different filling ratios (filling volume/effective volume: 30%, 60% and 90%) of polycaprolactone (PCL). Above 98% of nitrate removal efficiency was achieved with low accumulations of nitrite and ammonium for each filling ratio. Low filling ratio of PCL had extensive folds and pores that favored the attachment and growth of microorganisms; however, excessive biomass restrained nitrate specific reduction rate (NaSRR). The most dominant genera were Comamonas (0.80-57.64%), Stenotrophomonas (2.59-54.39%), Acidovorax (7.32-23.55%), Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium (0.30-19.74%) and Thermomonas (0.12-14.58%). Nitrate reductase (EC 1.7.99.4), nitrite reductase (EC 1.7.2.1) and nitric oxide reductase (EC 1.7.2.5) predicted by PICRUSt2 were abundant in high influent nitrate load (NaL). According to the analysis of carbon balance model, the utilization rate (η) of PCL showed a highly positive correlation with influent NaL, indicating reducing filling ratio or HRT might be an effective measure to save cost for nitrate removal.}, } @article {pmid34157063, year = {2021}, author = {Burgueño-Barris, G and Camps-Font, O and Figueiredo, R and Valmaseda-Castellón, E}, title = {The Influence of Implantoplasty on Surface Roughness, Biofilm Formation, and Biocompatibility of Titanium Implants: A Systematic Review.}, journal = {The International journal of oral & maxillofacial implants}, volume = {36}, number = {5}, pages = {e111–e119}, doi = {10.11607/jomi.8785}, pmid = {34157063}, issn = {1942-4434}, mesh = {Biofilms ; *Dental Implants ; Humans ; Materials Testing ; Surface Properties ; *Titanium ; }, abstract = {PURPOSE: A review was done to evaluate the effect of implantoplasty on surface roughness, biofilm formation, and biocompatibility of dental implants.

MATERIALS AND METHODS: Electronic searches were done in PubMed (OVID), Scopus, Web of Science, and The Cochrane Library to identify all relevant articles published until April 2020. All publications evaluating changes in implant surfaces after implantoplasty were included. The primary outcome variable was roughness of the implant surface. Secondary outcome variables were biofilm elimination and regrowth, changes in surface elements, and cell viability.

RESULTS: A total of 11 in vitro studies and two in vivo publications were included. Implantoplasty reduced surface roughness of the implant. The final outcome depended on the bur protocol, with tungsten carbide burs providing the smoothest surfaces, followed by silicone polishers. Implantoplasty did not affect cell viability, and roughness was inversely correlated to human gingival fibroblast growth. The technique also proved effective in removing biofilm and preventing its regrowth.

CONCLUSION: Implantoplasty reduces the surface roughness of dental implants, which in turn inhibits biofilm formation without affecting the biocompatibility of titanium implants. Since most of the included studies were done in an in vitro setting, further clinical trials are necessary to confirm these outcomes.}, } @article {pmid34156766, year = {2021}, author = {Seo, M and Oh, T and Bae, S}, title = {Antibiofilm activity of silver nanoparticles against biofilm forming Staphylococcus pseudintermedius isolated from dogs with otitis externa.}, journal = {Veterinary medicine and science}, volume = {7}, number = {5}, pages = {1551-1557}, pmid = {34156766}, issn = {2053-1095}, mesh = {Animals ; Biofilms ; *Dog Diseases/drug therapy ; Dogs ; *Metal Nanoparticles ; Microbial Sensitivity Tests/veterinary ; *Otitis Externa/drug therapy/microbiology/veterinary ; Silver/pharmacology ; Staphylococcus ; }, abstract = {BACKGROUND: Silver nanoparticles (AgNPs) are known to possess antimicrobial properties. Although the antibiofilm activity of AgNPs has been demonstrated in humans, this activity has not yet been elucidated in veterinary medicine.

OBJECTIVES: The purpose of this study was to evaluate the antibiofilm activity of silver nanoparticles against Staphylococcus pseudintermedius.

METHODS: Ten isolates of S. pseudintermedius obtained from dogs with otitis externa were treated with AgNPs, and the antibiofilm activity was measured using a modified microtiter plate and Congo red agar (CRA) method and scanning electron microscopy.

RESULTS: AgNPs displayed a significant dose-dependent antibiofilm activity and reduced biofilm formation at concentrations of 20 and 10 µg/ml (p < 0.05). S. pseudintermedius exposed to 20 µg/ml of AgNPs formed less bacterial slime compared to the controls on CRA plates. Scanning electron micrographs showed that the biofilm had few individually scattered cells along its surface when treated with AgNP concentrations of 20 and 10 µg/ml. Untreated surfaces showed an aggregated biofilm.

CONCLUSIONS: Our results suggested that AgNP may be a valuable alternative antibiofilm agent for canine otitis externa.}, } @article {pmid34156757, year = {2022}, author = {Kim, YG and Lee, JH and Park, S and Kim, S and Lee, J}, title = {Inhibition of polymicrobial biofilm formation by saw palmetto oil, lauric acid and myristic acid.}, journal = {Microbial biotechnology}, volume = {15}, number = {2}, pages = {590-602}, pmid = {34156757}, issn = {1751-7915}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Candida albicans ; *Escherichia coli O157 ; Lauric Acids/pharmacology ; Myristic Acid/pharmacology ; Plant Extracts ; Serenoa ; *Staphylococcus aureus ; }, abstract = {Biofilms are communities of bacteria, fungi or yeasts that form on diverse biotic or abiotic surfaces, and play important roles in pathogenesis and drug resistance. A generic saw palmetto oil inhibited biofilm formation by Staphylococcus aureus, Escherichia coli O157:H7 and fungal Candida albicans without affecting their planktonic cell growth. Two main components of the oil, lauric acid and myristic acid, are responsible for this antibiofilm activity. Their antibiofilm activities were observed in dual-species biofilms as well as three-species biofilms of S. aureus, E. coli O157:H7 and C. albicans. Transcriptomic analysis showed that lauric acid and myristic acid repressed the expressions of haemolysin genes (hla and hld) in S. aureus, several biofilm-related genes (csgAB, fimH and flhD) in E. coli and hypha cell wall gene HWP1 in C. albicans, which supported biofilm inhibition. Also, saw palmetto oil, lauric acid and myristic acid reduced virulence of three microbes in a nematode infection model and exhibited minimal cytotoxicity. Furthermore, combinatorial treatment of fatty acids and antibiotics showed synergistic antibacterial efficacy against S. aureus and E. coli O157:H7. These results demonstrate that saw palmetto oil and its main fatty acids might be useful for controlling bacterial infections as well as multispecies biofilms.}, } @article {pmid34156584, year = {2021}, author = {Li, M and Li, P and Chen, L and Guo, G and Xiao, Y and Chen, L and Du, H and Zhang, W}, title = {Identification of a phage-derived depolymerase specific for KL64 capsule of Klebsiella pneumoniae and its anti-biofilm effect.}, journal = {Virus genes}, volume = {57}, number = {5}, pages = {434-442}, pmid = {34156584}, issn = {1572-994X}, support = {U1803109//National Natural Science Foundation of China/ ; }, mesh = {Bacteriophages/enzymology/*genetics/pathogenicity ; Biofilms/growth & development ; Carbapenem-Resistant Enterobacteriaceae/genetics/virology ; Caudovirales/enzymology/genetics/pathogenicity ; Genome, Viral/*genetics ; Glycoside Hydrolases/*genetics ; Humans ; Klebsiella pneumoniae/*genetics/pathogenicity/virology ; Viral Proteins/genetics ; }, abstract = {The increasing prevalence of Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a serious threat to global health. Phages and phage-derived enzymes gained increasing attention for controling CRKP infections. In this study, a lytic phage P510 infecting KL64 type K. pneumoniae was isolated and characterized. Whole genome analysis and electron microscopy analysis showed that phage P510 belonged to genus Przondovirus, family Autographiviridae, the order Caudovirales. The tail fiber protein of the phage was predicted to encode capsule depolymerase. Further analysis demonstrated that recombinant depolymerase P510dep had polysaccharide-degrading activity against KL64-types capsule of K. pneumoniae, and its lysis spectrum matched to host range of phage P510. We also demonstrated that the recombinant depolymerase was able to significantly inhibit biofilm formation. The discovery of the phage-derived depolymerase lays the foundation for controlling the spread of CRKPs.}, } @article {pmid34156547, year = {2021}, author = {Zarghami, V and Ghorbani, M and Bagheri, KP and Shokrgozar, MA}, title = {Prevention the formation of biofilm on orthopedic implants by melittin thin layer on chitosan/bioactive glass/vancomycin coatings.}, journal = {Journal of materials science. Materials in medicine}, volume = {32}, number = {7}, pages = {75}, pmid = {34156547}, issn = {1573-4838}, mesh = {3T3 Cells ; Animals ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Peptides/pharmacology ; Bacterial Adhesion/drug effects ; *Biofilms ; Bone Substitutes/chemistry ; Cell Proliferation ; Ceramics/*chemistry ; Chitosan/chemistry ; Coated Materials, Biocompatible/chemistry ; Melitten/*administration & dosage/chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Microscopy, Electron, Scanning ; Nanoparticles/chemistry ; *Orthopedics ; Powders ; *Prostheses and Implants ; Staphylococcus aureus/*drug effects ; Surface Properties ; Titanium/chemistry ; Vancomycin/*administration & dosage/*chemistry ; Vancomycin Resistance/*drug effects ; }, abstract = {Methicillin-resistant and Vancomycin-resistant Staphylococcus aureus bacteria (MRSA and VRSA, respectively) can seriously jeopardizes bone implants. This research aimed to examine the potential synergistic effects of Melittin and vancomycin in preventing MRSA and VRSA associated bone implant infections. Chitosan/bioactive glass nanoparticles/vancomycin composites were coated on hydrothermally etched titanium substrates by casting method. The composite coatings were coated by Melittin through drop casting technique. Melittin raised the proliferation of MC3T3 cells, making it an appropriate option as osteoinductive and antibacterial substance in coatings of orthopedic implants. Composite coatings having combined vancomycin and Melittin eliminated both planktonic and adherent MRSA and VRSA bacteria, whereas coatings containing one of them failed to kill the whole VRSA bacteria. Therefore, chitosan/bioactive glass/vancomycin/Melittin coating can be used as a bone implant coating because of its anti-infective properties.}, } @article {pmid34156290, year = {2021}, author = {Savijoki, K and Myllymäki, H and Luukinen, H and Paulamäki, L and Vanha-Aho, LM and Svorjova, A and Miettinen, I and Fallarero, A and Ihalainen, TO and Yli-Kauhaluoma, J and Nyman, TA and Parikka, M}, title = {Surface-Shaving Proteomics of Mycobacterium marinum Identifies Biofilm Subtype-Specific Changes Affecting Virulence, Tolerance, and Persistence.}, journal = {mSystems}, volume = {6}, number = {3}, pages = {e0050021}, pmid = {34156290}, issn = {2379-5077}, support = {Sigrid Juselius Foundation//Sigrid Juselius Foundation/ ; Foundation of the Finnish Anti-Tuberculosis Association//Foundation of the Finnish Anti-Tuberculosis Association/ ; Foundation of the Finnish Anti-Tuberculosis Association//Foundation of the Finnish Anti-Tuberculosis Association/ ; Foundation of the Finnish Anti-Tuberculosis Association//Foundation of the Finnish Anti-Tuberculosis Association/ ; 295910//Research Council of Norway INFRASTRUKTUR-program/ ; 322010//Academy of Finland (Suomen Akatemia)/ ; 322010//Academy of Finland (Suomen Akatemia)/ ; 322010//Academy of Finland (Suomen Akatemia)/ ; 326674//Academy of Finland (Suomen Akatemia)/ ; Jane and Aatos Erkko Foundation//Jane and Aatos Erkko Foundation/ ; }, abstract = {The complex cell wall and biofilm matrix (ECM) act as key barriers to antibiotics in mycobacteria. Here, the ECM and envelope proteins of Mycobacterium marinum ATCC 927, a nontuberculous mycobacterial model, were monitored over 3 months by label-free proteomics and compared with cell surface proteins on planktonic cells to uncover pathways leading to virulence, tolerance, and persistence. We show that ATCC 927 forms pellicle-type and submerged-type biofilms (PBFs and SBFs, respectively) after 2 weeks and 2 days of growth, respectively, and that the increased CelA1 synthesis in this strain prevents biofilm formation and leads to reduced rifampicin tolerance. The proteomic data suggest that specific changes in mycolic acid synthesis (cord factor), Esx1 secretion, and cell wall adhesins explain the appearance of PBFs as ribbon-like cords and SBFs as lichen-like structures. A subpopulation of cells resisting 64× MIC rifampicin (persisters) was detected in both biofilm subtypes and already in 1-week-old SBFs. The key forces boosting their development could include subtype-dependent changes in asymmetric cell division, cell wall biogenesis, tricarboxylic acid/glyoxylate cycle activities, and energy/redox/iron metabolisms. The effect of various ambient oxygen tensions on each cell type and nonclassical protein secretion are likely factors explaining the majority of the subtype-specific changes. The proteomic findings also imply that Esx1-type protein secretion is more efficient in planktonic (PL) and PBF cells, while SBF may prefer both the Esx5 and nonclassical pathways to control virulence and prolonged viability/persistence. In conclusion, this study reports the first proteomic insight into aging mycobacterial biofilm ECMs and indicates biofilm subtype-dependent mechanisms conferring increased adaptive potential and virulence of nontuberculous mycobacteria. IMPORTANCE Mycobacteria are naturally resilient, and mycobacterial infections are notoriously difficult to treat with antibiotics, with biofilm formation being the main factor complicating the successful treatment of tuberculosis (TB). The present study shows that nontuberculous Mycobacterium marinum ATCC 927 forms submerged- and pellicle-type biofilms with lichen- and ribbon-like structures, respectively, as well as persister cells under the same conditions. We show that both biofilm subtypes differ in terms of virulence-, tolerance-, and persistence-conferring activities, highlighting the fact that both subtypes should be targeted to maximize the power of antimycobacterial treatment therapies.}, } @article {pmid34155333, year = {2021}, author = {Tremblay, YDN and Durand, BAR and Hamiot, A and Martin-Verstraete, I and Oberkampf, M and Monot, M and Dupuy, B}, title = {Metabolic adaption to extracellular pyruvate triggers biofilm formation in Clostridioides difficile.}, journal = {The ISME journal}, volume = {15}, number = {12}, pages = {3623-3635}, pmid = {34155333}, issn = {1751-7370}, mesh = {Biofilms ; Clostridioides ; *Clostridioides difficile ; *Clostridium Infections ; Humans ; Pyruvic Acid ; }, abstract = {Clostridioides difficile infections are associated with gut microbiome dysbiosis and are the leading cause of hospital-acquired diarrhoea. The infectious process is strongly influenced by the microbiota and successful infection relies on the absence of specific microbiota-produced metabolites. Deoxycholate and short-chain fatty acids are microbiota-produced metabolites that limit the growth of C. difficile and protect the host against this infection. In a previous study, we showed that deoxycholate causes C. difficile to form strongly adherent biofilms after 48 h. Here, our objectives were to identify and characterize key molecules and events required for biofilm formation in the presence of deoxycholate. We applied time-course transcriptomics and genetics to identify sigma factors, metabolic processes and type IV pili that drive biofilm formation. These analyses revealed that extracellular pyruvate induces biofilm formation in the presence of deoxycholate. In the absence of deoxycholate, pyruvate supplementation was sufficient to induce biofilm formation in a process that was dependent on pyruvate uptake by the membrane protein CstA. In the context of the human gut, microbiota-generated pyruvate is a metabolite that limits pathogen colonization. Taken together our results suggest that pyruvate-induced biofilm formation might act as a key process driving C. difficile persistence in the gut.}, } @article {pmid34154415, year = {2021}, author = {Perkins, A and Tudorica, DA and Teixeira, RD and Schirmer, T and Zumwalt, L and Ogba, OM and Cassidy, CK and Stansfeld, PJ and Guillemin, K}, title = {A Bacterial Inflammation Sensor Regulates c-di-GMP Signaling, Adhesion, and Biofilm Formation.}, journal = {mBio}, volume = {12}, number = {3}, pages = {e0017321}, pmid = {34154415}, issn = {2150-7511}, support = {F32 DK115195/DK/NIDDK NIH HHS/United States ; K99 AI148587/AI/NIAID NIH HHS/United States ; P01 GM125576/GM/NIGMS NIH HHS/United States ; BB/S003339/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacteria/classification/genetics/immunology/metabolism ; Bacterial Adhesion/*genetics/immunology ; Biofilms/drug effects/*growth & development ; Cyclic GMP/*analogs & derivatives/genetics/metabolism ; Escherichia coli/drug effects/*genetics/immunology/metabolism ; Escherichia coli Proteins/*genetics/immunology/metabolism ; *Gene Expression Regulation, Bacterial ; Genome, Bacterial ; Hypochlorous Acid/pharmacology ; Inflammation/*genetics/immunology ; *Signal Transduction ; }, abstract = {Bacteria that colonize animals must overcome, or coexist, with the reactive oxygen species products of inflammation, a front-line defense of innate immunity. Among these is the neutrophilic oxidant bleach, hypochlorous acid (HOCl), a potent antimicrobial that plays a primary role in killing bacteria through nonspecific oxidation of proteins, lipids, and DNA. Here, we report that in response to increasing HOCl levels, Escherichia coli regulates biofilm production via activation of the diguanylate cyclase DgcZ. We identify the mechanism of DgcZ sensing of HOCl to be direct oxidation of its regulatory chemoreceptor zinc-binding (CZB) domain. Dissection of CZB signal transduction reveals that oxidation of the conserved zinc-binding cysteine controls CZB Zn[2+] occupancy, which in turn regulates the catalysis of c-di-GMP by the associated GGDEF domain. We find DgcZ-dependent biofilm formation and HOCl sensing to be regulated in vivo by the conserved zinc-coordinating cysteine. Additionally, point mutants that mimic oxidized CZB states increase total biofilm. A survey of bacterial genomes reveals that many pathogenic bacteria that manipulate host inflammation as part of their colonization strategy possess CZB-regulated diguanylate cyclases and chemoreceptors. Our findings suggest that CZB domains are zinc-sensitive regulators that allow host-associated bacteria to perceive host inflammation through reactivity with HOCl. IMPORTANCE Immune cells are well equipped to eliminate invading bacteria, and one of their primary tools is the synthesis of bleach, hypochlorous acid (HOCl), the same chemical used as a household disinfectant. In this work, we present findings showing that many host-associated bacteria possess a bleach-sensing protein that allows them to adapt to the presence of this chemical in their environment. We find that the bacterium Escherichia coli responds to bleach by hunkering down and producing a sticky matrix known as biofilm, which helps it aggregate and adhere to surfaces. This behavior may play an important role in pathogenicity for E. coli and other bacteria, as it allows the bacteria to detect and adapt to the weapons of the host immune system.}, } @article {pmid34154406, year = {2021}, author = {Guo, H and Rischer, M and Westermann, M and Beemelmanns, C}, title = {Two Distinct Bacterial Biofilm Components Trigger Metamorphosis in the Colonial Hydrozoan Hydractinia echinata.}, journal = {mBio}, volume = {12}, number = {3}, pages = {e0040121}, pmid = {34154406}, issn = {2150-7511}, mesh = {Animals ; *Biofilms ; Coral Reefs ; Ecosystem ; Hydrozoa/*microbiology/*physiology ; Larva/*microbiology ; *Metamorphosis, Biological ; }, abstract = {In marine environments, the bacterially induced metamorphosis of larvae is a widespread cross-kingdom communication phenomenon that is critical for the persistence of many marine invertebrates. However, the majority of inducing bacterial signals and underlying cellular mechanisms remain enigmatic. The marine hydroid Hydractinia echinata is a well-known model system for investigating bacterially stimulated larval metamorphosis, as larvae transform into the colonial adult stage within 24 h of signal detection. Although H. echinata has served as a cell biological model system for decades, the identity and influence of bacterial signals on the morphogenic transition remained largely unexplored. Using a bioassay-guided analysis, we first determined that specific bacterial (lyso)phospholipids, naturally present in bacterial membranes and vesicles, elicit metamorphosis in Hydractinia larvae in a dose-response manner. Lysophospholipids, as single compounds or in combination (50 μM), induced metamorphosis in up to 50% of all larvae within 48 h. Using fluorescence-labeled bacterial phospholipids, we demonstrated that phospholipids are incorporated into the larval membranes, where interactions with internal signaling cascades are proposed to occur. Second, we identified two structurally distinct exopolysaccharides of bacterial biofilms, the new Rha-Man polysaccharide from Pseudoalteromonas sp. strain P1-9 and curdlan from Alcaligenes faecalis, to induce metamorphosis in up to 75% of tested larvae. We also found that combinations of (lyso)phospholipids and curdlan induced transformation within 24 h, thereby exceeding the morphogenic activity observed for single compounds and bacterial biofilms. Our results demonstrate that two structurally distinct, bacterium-derived metabolites converge to induce high transformation rates of Hydractinia larvae and thus may help ensure optimal habitat selection. IMPORTANCE Bacterial biofilms profoundly influence the recruitment and settlement of marine invertebrates, critical steps for diverse marine processes such as the formation of coral reefs, the maintenance of marine fisheries, and the fouling of submerged surfaces. However, the complex composition of biofilms often makes the characterization of individual signals and regulatory mechanisms challenging. Developing tractable model systems to characterize these coevolved interactions is the key to understanding fundamental processes in evolutionary biology. Here, we characterized two types of bacterial signaling molecules, phospholipids and polysaccharides, that induce the morphogenic transition. We then analyzed their abundance and combinatorial activity. This study highlights the general importance of multiple bacterial signal converging activity in development-related cross-kingdom signaling and poses the question of whether complex lipids and polysaccharides are general metamorphic cues for cnidarian larvae.}, } @article {pmid34150727, year = {2021}, author = {Zhang, H and Yang, P and Wang, Z and Li, M and Zhang, J and Liu, D and Chen, Y and Ying, H}, title = {Clostridium acetobutylicum Biofilm: Advances in Understanding the Basis.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {9}, number = {}, pages = {658568}, pmid = {34150727}, issn = {2296-4185}, abstract = {Clostridium acetobutylicum is an important industrial platform capable of producing a variety of biofuels and bulk chemicals. Biofilm of C. acetobutylicum renders many production advantages and has been long and extensively applied in fermentation. However, molecular and genetic mechanisms underlying the biofilm have been much less studied and remain largely unknown. Here, we review studies to date focusing on C. acetobutylicum biofilms, especially on its physiological and molecular aspects, summarizing the production advantages, cell physiological changes, extracellular matrix components and regulatory genes of the biofilm. This represents the first review dedicated to the biofilm of C. acetobutylicum. Hopefully, it will deepen our understanding toward C. acetobutylicum biofilm and inspire more research to learn and develop more efficient biofilm processes in this industrially important bacterium.}, } @article {pmid34150264, year = {2021}, author = {Ginter-Kramarczyk, D and Kruszelnicka, I and Michałkiewicz, M and Muszyński, P and Zajchowski, S and Tomaszewska, J}, title = {Biofilm on the polymer composites - qualitative and quantitative microbiological analysis.}, journal = {Journal of environmental health science & engineering}, volume = {19}, number = {1}, pages = {641-649}, pmid = {34150264}, issn = {2052-336X}, abstract = {BACKGROUND: Modern technology, which has been getting more and more recognition in the world for the last several years, is the moving bed biofilm reactor (MBBR) technology. Currently, movable biofilters made of basic polymeric materials, polyethylene and polypropylene.

METHODS: An innovative solution in the field, mainly because of the large active surface area for biological membrane can be wood polymer composites (WPC). In the research polypropylene (PP) and polyvinyl chloride (PVC) was used as the matrix. Two types of commercial wood flour also, selected from conifers, were selected for the study: Lignocel C 120 with particle sizes in the range of 70 μm-150 μm and L9 with dimensions of 0.8-1.1 mm and wood chips, which are used on an industrial scale for the production of chipboards, were used as a filler. A quantitative and qualitative analysis of newly formed biofilms was performed.

RESULTS: The study showed a direct effect of the filler and its particle size on the susceptibility to the formation of the biofilm of on the composites surface.

CONCLUSIONS: Polypropylene PPH 648 T and 40% wt. of L9 type wood flour was the most susceptible to biofilm formation. Pure polypropylene PPH 648 T was the least susceptible material.}, } @article {pmid34149678, year = {2021}, author = {She, P and Zhou, L and Li, S and Liu, Y and Xu, L and Chen, L and Luo, Z and Wu, Y}, title = {Corrigendum: Synergistic Microbicidal Effect of Auranofin and Antibiotics Against Planktonic and Biofilm-Encased S. aureus and E. faecalis.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {694670}, doi = {10.3389/fmicb.2021.694670}, pmid = {34149678}, issn = {1664-302X}, abstract = {[This corrects the article DOI: 10.3389/fmicb.2019.02453.].}, } @article {pmid34149663, year = {2021}, author = {Doghri, I and Cherifi, T and Goetz, C and Malouin, F and Jacques, M and Fravalo, P}, title = {Counteracting Bacterial Motility: A Promising Strategy to Narrow Listeria monocytogenes Biofilm in Food Processing Industry.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {673484}, pmid = {34149663}, issn = {1664-302X}, abstract = {Listeria monocytogenes (L. monocytogenes) is often associated with processed food as it can form biofilms that represent a source of contamination at all stages of the manufacturing chain. The control and prevention of biofilms in food-processing plants are of utmost importance. This study explores the efficacy of prospect molecules for counteracting bacterial mechanisms leading to biofilm formation. The compounds included the phytomolecule tomatidine, zinc chloride (ZnCl2), ethylenediaminetetraacetic acid (EDTA), and a more complexed mixture of bacterial compounds from coagulase-negative staphylococci (CNS exoproducts). Significant inhibition of L. monocytogenes biofilm formation was evidenced using a microfluidic system and confocal microscopic analyses (p < 0.001). Active molecules were effective at an early stage of biofilm development (≥50% of inhibition) but failed to disperse mature biofilms of L. monocytogenes. According to our findings, prevention of surface attachment was associated with a disruption of bacterial motility. Indeed, agar cell motility assays demonstrated the effectiveness of these molecules. Overall, results highlighted the critical role of motility in biofilm formation and allow to consider flagellum-mediated motility as a promising molecular target in control strategies against L. monocytogenes in food processing environments.}, } @article {pmid34149659, year = {2021}, author = {Zheng, X and Chen, L and Zeng, W and Liao, W and Wang, Z and Tian, X and Fang, R and Sun, Y and Zhou, T}, title = {Antibacterial and Anti-biofilm Efficacy of Chinese Dragon's Blood Against Staphylococcus aureus Isolated From Infected Wounds.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {672943}, pmid = {34149659}, issn = {1664-302X}, abstract = {Chinese dragon's blood (CDB), a characteristic red resin, is an important traditional Chinese medicine (TCM), and empiric therapy of infected wounds with CDB is performed in clinical settings. For the first time, we herein report the antibacterial and anti-biofilm efficacy of CDB against Staphylococcus aureus (S. aureus). Antimicrobial susceptibility testing, growth curve assay, time-kill curve assay, crystal violet biofilm assay, scanning electron microscope (SEM) analysis, cell membrane tests, and quantitative real-time polymerase chain reaction (qRT-PCR) were used for this purpose. The results suggested that the minimum inhibitory concentration (MIC) values of CDB against S. aureus ranged from 32 to 128 μg/mL. Growth curves and time-kill curves confirmed that CDB could inhibit the growth of S. aureus. The biofilm formation ability and the expression levels of saeR, saeS, and hla of S. aureus in the presence and absence of CDB were statistically significant (P < 0.01). The results of SEM analysis and cell membrane tests revealed that exposure to CDB had some destructive effects on S. aureus cells. In conclusion, CDB exhibits positive antibacterial activity against S. aureus. Moreover, CDB could reduce the biofilm formation and the virulence factors of S. aureus by downregulating the expression levels of saeR, saeS, and hla genes. These findings indicated that CDB has immense potential to serve as a viable alternative for the treatment of infected wounds caused by S. aureus in clinical settings.}, } @article {pmid34149654, year = {2021}, author = {Cabau-Peinado, O and Straathof, AJJ and Jourdin, L}, title = {A General Model for Biofilm-Driven Microbial Electrosynthesis of Carboxylates From CO2.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {669218}, pmid = {34149654}, issn = {1664-302X}, abstract = {Up to now, computational modeling of microbial electrosynthesis (MES) has been underexplored, but is necessary to achieve breakthrough understanding of the process-limiting steps. Here, a general framework for modeling microbial kinetics in a MES reactor is presented. A thermodynamic approach is used to link microbial metabolism to the electrochemical reduction of an intracellular mediator, allowing to predict cellular growth and current consumption. The model accounts for CO2 reduction to acetate, and further elongation to n-butyrate and n-caproate. Simulation results were compared with experimental data obtained from different sources and proved the model is able to successfully describe microbial kinetics (growth, chain elongation, and product inhibition) and reactor performance (current density, organics titer). The capacity of the model to simulate different system configurations is also shown. Model results suggest CO2 dissolved concentration might be limiting existing MES systems, and highlight the importance of the delivery method utilized to supply it. Simulation results also indicate that for biofilm-driven reactors, continuous mode significantly enhances microbial growth and might allow denser biofilms to be formed and higher current densities to be achieved.}, } @article {pmid34148884, year = {2021}, author = {Hou, Z and Zhang, B and She, P and Wu, Y and Zhang, R}, title = {Anti-planktonic and anti-biofilm effects of two synthetic anti-microbial peptides against Staphylococcus epidermidis.}, journal = {Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences}, volume = {46}, number = {5}, pages = {481-487}, doi = {10.11817/j.issn.1672-7347.2021.200360}, pmid = {34148884}, issn = {1672-7347}, support = {kq1907012//the Science and Technology Project of Changsha, China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; Peptides ; *Plankton ; *Staphylococcus epidermidis ; }, abstract = {OBJECTIVES: Staphylococcus epidermidis is one of the most common Gram-positive cocci in nosocomial infection, which could adhere to the surface of medical apparatus and causes biofilm-related infections. In the present study, we aim to explore the antimicrobial effects of GH12 and SAAP-148 against Staphylococcus epidermidis.

METHODS: Micro-dilution methods were used to detect the minimal inhibitory/bactericidal concentration of peptides on Staphylococcus epidermidis. Biofilm formation positive type strain was used to determine the antibiofilm effects of the peptides. Biofilms were built on the cover slides and fluorescent dye SYTO9 and laser confocal microscope were used to observe the effects of peptides on the three-dimensional structure of Staphylococcus epidermidis biofilms. The cell membrane permeability of Staphylococcus epidermidis was detected by flow cytometry. Expressions of icaA and icaDgenes were analyzed by real-time reverse transcription PCR.

RESULTS: The minimal inhibitory concentrations of GH12 and SAAP-148 against Staphylococcus epidermidis were 8 and 16 μg/mL, respectively, and the minimal bactericidal concentration was 64 μg/mL. GH12 and SAAP-148 significantly inhibited the biofilm formation of Staphylococcus epidermidis at the concentration of 8 μg/mL (t=7.193, P<0.05) and 16 μg/mL (t=7.808, P<0.05), respectively. Similarly, the GH12 and SAAP-148 significantly eradicated the pre-formed biofilms at the concentration of 16 μg/mL (t=5.369, P<0.05) and 32 μg/mL (t=4.474, P<0.05) in a dose-response manner, respectively. Meanwhile, the two peptides broke the structure of biofims and reduce the total biomass. GH12 and SAAP-148 at the concentration of minimal inhibitory concentration significantly disrupted the cell membrane of Staphylococcus epidermidis. The expressions of icaA and icaDgenes were significantly inhibited by antimicrobial peptides at the 1×minimal inhibitory concentration.

CONCLUSIONS: GH12 and SAAP-148 show significantly antimicrobial and anti-biofilm effects against Staphylococcus epidermidis by disruption of cell membrane and inhibition of icaAand icaDgene expression.}, } @article {pmid34148448, year = {2021}, author = {Dennington, SPJ and Jackson, A and Finnie, AA and Wharton, JA and Longyear, JE and Stoodley, P}, title = {A rapid benchtop method to assess biofilm on marine fouling control coatings.}, journal = {Biofouling}, volume = {37}, number = {4}, pages = {452-464}, pmid = {34148448}, issn = {1029-2454}, support = {BB/P004164/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms ; *Biofouling/prevention & control ; Hydrodynamics ; Surface Properties ; }, abstract = {A rapid benchtop method to measure the torque associated with minidiscs rotating in water using a sensitive analytical rheometer has been used to monitor the drag caused by marine fouling on coated discs. The method was calibrated using sandpaper surfaces of known roughness. Minidiscs coated with commercial fouling control coatings, plus an inactive control, were exposed in an estuarine harbour. After 176 days the drag on the fouling control-coated discs, expressed as a moment coefficient, was between 73% and 90% less than the drag on the control coating. The method has potential use as a screen for novel antifouling and drag reducing coatings and surfaces. Roughness functions derived using Granville's indirect similarity law are similar to patterns found in the general hydrodynamics literature, and so rotational minidisc results can be considered with reference to other fouling drag datasets.Supplemental data for this article is available online at https://doi.org/10.1080/08927014.2021.1929937 .}, } @article {pmid34146871, year = {2021}, author = {Mier, AA and Olvera-Vargas, H and Mejía-López, M and Longoria, A and Verea, L and Sebastian, PJ and Arias, DM}, title = {A review of recent advances in electrode materials for emerging bioelectrochemical systems: From biofilm-bearing anodes to specialized cathodes.}, journal = {Chemosphere}, volume = {283}, number = {}, pages = {131138}, doi = {10.1016/j.chemosphere.2021.131138}, pmid = {34146871}, issn = {1879-1298}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Electrolysis ; Wastewater/analysis ; }, abstract = {Bioelectrochemical systems (BES), mainly microbial fuel cells (MEC) and microbial electrolysis cells (MFC), are unique biosystems that use electroactive bacteria (EAB) to produce electrons in the form of electric energy for different applications. BES have attracted increasing attention as a sustainable, low-cost, and neutral-carbon option for energy production, wastewater treatment, and biosynthesis. Complex interactions between EAB and the electrode materials play a crucial role in system performance and scalability. The electron transfer processes from the EAB to the anode surface or from the cathode surface to the EAB have been the object of numerous investigations in BES, and the development of new materials to maximize energy production and overall performance has been a hot topic in the last years. The present review paper discusses the advances on innovative electrode materials for emerging BES, which include MEC coupled to anaerobic digestion (MEC-AD), Microbial Desalination Cells (MDC), plant-MFC (P-MFC), constructed wetlands-MFC (CW-MFC), and microbial electro-Fenton (BEF). Detailed insights on innovative electrode modification strategies to improve the electrode transfer kinetics on each emerging BES are provided. The effect of materials on microbial population is also discussed in this review. Furthermore, the challenges and opportunities for materials scientists and engineers working in BES are presented at the end of this work aiming at scaling up and industrialization of such versatile systems.}, } @article {pmid34144836, year = {2021}, author = {Ruiz-Gaitán, A and Del Pozo, JL}, title = {[AmBisome, three challenges: Candida auris infection, central nervous system infection, and biofilm-associated infection].}, journal = {Revista iberoamericana de micologia}, volume = {38}, number = {2}, pages = {84-90}, doi = {10.1016/j.riam.2021.03.004}, pmid = {34144836}, issn = {2173-9188}, mesh = {Amphotericin B ; Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; *Candidiasis, Invasive/diagnosis/drug therapy ; *Central Nervous System Infections/drug therapy ; Humans ; Microbial Sensitivity Tests ; }, abstract = {The treatment of invasive fungal infections remains a challenge, both for the diagnosis and for the need of providing the appropriate antifungal therapy. Candida auris is a pathogenic yeast that is responsible for hospital outbreaks, especially in intensive care units; it is characterized by a high resistance to the antifungal agents and can become multidrug-resistant. At present, the recommended antifungal agents for the invasive infections with this pathogen are echinocandins, always after carrying out an antifungal susceptibility testing. In case of no clinical response or persistent candidemia, the addition of liposomal amphotericin B or isavuconazole may be considered. Both fungal infection of the central nervous system and that associated with biomedical devices remain rare entities affecting mainly immunocompromised patients. However, an increase in their incidence in recent years, along with high morbidity and mortality, has been shown. The treatment of these infections is conditioned by the limited knowledge of the pharmacokinetic properties of antifungals. A better understanding of the pharmacokinetic and pharmacodynamic parameters of the different antifungals is essential to determine the efficacy of the antifungal agents in the treatment of these infections.}, } @article {pmid34144677, year = {2021}, author = {Blank, E and Grischke, J and Winkel, A and Eberhard, J and Kommerein, N and Doll, K and Yang, I and Stiesch, M}, title = {Evaluation of biofilm colonization on multi-part dental implants in a rat model.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {313}, pmid = {34144677}, issn = {1472-6831}, mesh = {Animals ; Biofilms ; *Dental Implants/adverse effects ; Female ; *Peri-Implantitis ; Porphyromonas gingivalis ; Rats ; Rats, Sprague-Dawley ; }, abstract = {BACKGROUND: Peri-implant mucositis and peri-implantitis are highly prevalent biofilm-associated diseases affecting the tissues surrounding dental implants. As antibiotic treatment is ineffective to fully cure biofilm mediated infections, antimicrobial modifications of implants to reduce or prevent bacterial colonization are called for. Preclinical in vivo evaluation of the functionality of new or modified implant materials concerning bacterial colonization and peri-implant health is needed to allow progress in this research field. For this purpose reliable animal models are needed.

METHODS: Custom made endosseous dental implants were installed in female Sprague Dawley rats following a newly established three-step implantation procedure. After healing of the bone and soft tissue, the animals were assigned to two groups. Group A received a continuous antibiotic treatment for 7 weeks, while group B was repeatedly orally inoculated with human-derived strains of Streptococcus oralis, Fusobacterium nucleatum and Porphyromonas gingivalis for six weeks, followed by 1 week without inoculation. At the end of the experiment, implantation sites were clinically assessed and biofilm colonization was quantified via confocal laser scanning microscopy. Biofilm samples were tested for presence of the administered bacteria via PCR analysis.

RESULTS: The inner part of the custom made implant screw could be identified as a site of reliable biofilm formation in vivo. S. oralis and F. nucleatum were detectable only in the biofilm samples from group B animals. P. gingivalis was not detectable in samples from either group. Quantification of the biofilm volume on the implant material revealed no statistically significant differences between the treatment groups. Clinical inspection of implants in group B animals showed signs of mild to moderate peri-implant mucositis (4 out of 6) whereas the mucosa of group A animals appeared healthy (8/8). The difference in the mucosa health status between the treatment groups was statistically significant (p = 0.015).

CONCLUSIONS: We developed a new rodent model for the preclinical evaluation of dental implant materials with a special focus on the early biofilm colonization including human-derived oral bacteria. Reliable biofilm quantification on the implant surface and the symptoms of peri-implant mucositis of the bacterially inoculated animals will serve as a readout for experimental evaluation of biofilm-reducing modifications of implant materials.}, } @article {pmid34144473, year = {2021}, author = {Li, Y and Liu, J and Chen, X and Yuan, X and Li, N and He, W and Feng, Y}, title = {Tailoring spatial structure of electroactive biofilm for enhanced activity and direct electron transfer on iron phthalocyanine modified anode in microbial fuel cells.}, journal = {Biosensors & bioelectronics}, volume = {191}, number = {}, pages = {113410}, doi = {10.1016/j.bios.2021.113410}, pmid = {34144473}, issn = {1873-4235}, mesh = {*Bioelectric Energy Sources ; Biofilms ; *Biosensing Techniques ; Electrodes ; Electrons ; Ferrous Compounds ; Indoles ; }, abstract = {Electroactive biofilm (EAB) has been considered as the core determining electricity generation in microbial fuel cells (MFCs), and its spatial structure regulation for enhanced activity and selectivity is of great concern. In this study, iron phthalocyanine (FePc) was introduced into a carbon cloth (CC) electrode, aiming at improving the affinity between the anode and outer membrane c-type cytochromes (OM c-Cyts) and achieving a highly active EAB. The FePc modified CC anode (FePc-CC) effectively improved the viability of EAB and enriched the Geobacter species up to 44.83% (FePc-CC) from 6.97% (CC). The FePc-CC anode achieved a much higher power density of 2419 mW m[-2] than the CC (560 mW m[-2]) and a remarkable higher biomass loading of 2477.2 ± 84.5 μg cm[-2] than the CC (749.3 ± 31.3 μg cm[-2]). As the charge transfer resistance was decreased by 58.6 times from 395.2 Ω (CC) to 6.74 Ω (FePc-CC), the interfacial reaction rate was accelerated and the direct electron transfer via OM c-Cyts was promoted. This work provides an effective method to improve the EAB activity by regulating its spatial structure, and opens the door toward the development of highly active EAB using metal phthalocyanines in MFCs.}, } @article {pmid34144395, year = {2021}, author = {Semcesen, PO and Wells, MG}, title = {Biofilm growth on buoyant microplastics leads to changes in settling rates: Implications for microplastic retention in the Great Lakes.}, journal = {Marine pollution bulletin}, volume = {170}, number = {}, pages = {112573}, doi = {10.1016/j.marpolbul.2021.112573}, pmid = {34144395}, issn = {1879-3363}, mesh = {Biofilms ; Environmental Monitoring ; Lakes ; *Microplastics ; Plastics ; *Water Pollutants, Chemical/analysis ; }, abstract = {Buoyant microplastic pollution disperses widely from sources via strong wind-driven water currents in lakes and oceans. This ability for dispersal depends critically upon the particle's density, which can change over time due to microbial growth (biofilm). This study quantifies biofilm-induced sinking rates of irregularly-shaped polypropylene granules (~125-2000 μm) via ex-situ experiments emulating a Great Lakes freshwater environment. Biofilm development increases particle density and lowers microplastic rise velocities, eventually causing sinking. We observed sinking for 100% of small and intermediate microplastics, and 95% of large microplastics. Under constant environmental conditions, sinking onset was observed sooner for smaller particles (~125-212 μm, 18 days) than for larger particles (~1000-2000 μm, 50 days). Differences in settling onset would lead to size-fractionation of particle sedimentation, whereby smaller particles are deposited closer to their sources relative to larger particles. Our study demonstrates a novel mechanism by which buoyant microplastics can selectively sink from the lake surface.}, } @article {pmid34143595, year = {2021}, author = {Li, M and Lan, X and Han, X and Shi, S and Sun, H and Kang, Y and Dan, J and Sun, J and Zhang, W and Wang, J}, title = {Acid-Induced Self-Catalyzing Platform Based on Dextran-Coated Copper Peroxide Nanoaggregates for Biofilm Treatment.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {25}, pages = {29269-29280}, doi = {10.1021/acsami.1c03409}, pmid = {34143595}, issn = {1944-8252}, mesh = {Animals ; *Anti-Bacterial Agents/chemistry/metabolism/pharmacology ; Biofilms/*drug effects ; *Copper/chemistry/pharmacology ; Dextrans/*chemistry ; Female ; Mice ; Mice, Inbred BALB C ; Nanoparticles/*chemistry ; Peroxides/chemistry ; Salmonella/drug effects ; Staphylococcus aureus/drug effects ; Wound Healing/drug effects ; }, abstract = {Nanoantibacterial agents based on catalytic activity were limited due to the low levels of endogenous H2O2 in the microenvironment of bacterial biofilms. However, the additional H2O2 will trigger more side effects to healthy surroundings, which is still a great challenge. Herein, we report an acid-induced self-catalyzing platform based on dextran-coated copper peroxide nanoaggregates (DCPNAs) for antibiofilm and local infection therapy applications. The dextran-functionalized DCPNAs were mediated and conveniently purified via a dextran and ethanol precipitation method, which can also cluster nanodots into nanoaggregates and show good penetrability as well as biocompatibility. Bacterial biofilms were inhibited and destroyed by the reactive oxygen species generated from the Fenton reaction between the Cu[2+] and H2O2 released from DCPNAs in an acidic environment, which did not require additional H2O2. As expected, the DCPNAs exhibit low cytotoxicity and excellent acid-induced antibacterial and antibiofilm ability. Moreover, the DCPNAs realized great therapeutic outcomes in the application for in vivo wound healing. The overall excellent properties associated with the DCPNAs highlight that they could be considered as a kind of ideal antimicrobial agents for microbial biofilm infection treatment.}, } @article {pmid34140515, year = {2021}, author = {Hollmann, B and Perkins, M and Chauhan, VM and Aylott, JW and Hardie, KR}, title = {Fluorescent nanosensors reveal dynamic pH gradients during biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {50}, pmid = {34140515}, issn = {2055-5008}, support = {BB/M008770/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Acrylic Resins/chemistry ; *Biofilms/growth & development ; *Biosensing Techniques ; Fluorescent Dyes/chemistry ; Glucose/metabolism ; *Hydrogen-Ion Concentration ; Nanoparticles/chemistry ; *Nanotechnology ; Permeability ; Pseudomonas/growth & development/metabolism ; Time-Lapse Imaging ; }, abstract = {Understanding the dynamic environmental microniches of biofilms will permit us to detect, manage and exploit these communities. The components and architecture of biofilms have been interrogated in depth; however, little is known about the environmental microniches present. This is primarily because of the absence of tools with the required measurement sensitivity and resolution to detect these changes. We describe the application of ratiometric fluorescent pH-sensitive nanosensors, as a tool, to observe physiological pH changes in biofilms in real time. Nanosensors comprised two pH-sensitive fluorophores covalently encapsulated with a reference pH-insensitive fluorophore in an inert polyacrylamide nanoparticle matrix. The nanosensors were used to analyse the real-time three-dimensional pH variation for two model biofilm formers: (i) opportunistic pathogen Pseudomonas aeruginosa and (ii) oral pathogen Streptococcus mutans. The detection of sugar metabolism in real time by nanosensors provides a potential application to identify therapeutic solutions to improve oral health.}, } @article {pmid34139901, year = {2021}, author = {Rathinam, P and Murari, BM and Viswanathan, P}, title = {Biofilm inhibition and antifouling evaluation of sol-gel coated silicone implants with prolonged release of eugenol against Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {37}, number = {5}, pages = {521-537}, doi = {10.1080/08927014.2021.1933960}, pmid = {34139901}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Biofouling/prevention & control ; Eugenol/pharmacology ; *Pseudomonas aeruginosa ; Quorum Sensing ; Silicones/pharmacology ; Virulence Factors ; }, abstract = {The incidence of biofilm-linked catheter-associated urinary tract infections (CAUTIs) is increasing across the world. However, there is no clinical evidence to support the modifications of biomaterials, such as antimicrobial agent-coated catheters, that are known to reduce the risk of bacterial colonization and resistance development. The present study developed and tested silicone segments coated with an antivirulence agent, eugenol. The parameters for sol-gel preparation and coating were tailored to achieve a prolonged release of eugenol (for >35 days) at predefined antivirulence doses from dip-coated thin films. The eugenol-coated segments could prevent biofilm formation by Pseudomonas aeruginosa PAO1 as well as bacterial adhesion. Significant repression in the expression of virulence and biofilm-associated genes were recorded, confirming the antivirulence and biofilm inhibition properties of silicone segments coated with eugenol. The drug release profiles, efficacy analysis, neutrophil-response studies, and in vitro toxicity profiling further supported the contention that the activity of the eugenol-coated sections was effective and safe.}, } @article {pmid34139566, year = {2021}, author = {Hong, P and Yang, K and Shu, Y and Xiao, B and Wu, H and Xie, Y and Gu, Y and Qian, F and Wu, X}, title = {Efficacy of auto-aggregating aerobic denitrifiers with coaggregation traits for bioaugmentation performance in biofilm-formation and nitrogen-removal.}, journal = {Bioresource technology}, volume = {337}, number = {}, pages = {125391}, doi = {10.1016/j.biortech.2021.125391}, pmid = {34139566}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; *Nitrogen/analysis ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {To promote efficiency nitrogen-rich wastewater treatment from a sequencing batch biofilm reactor (SBBR), three aerobic denitrifiers (Pseudomonas mendocinaIHB602, Methylobacterium gregansDC-1 and Pseudomonas stutzeriIHB618) with dual-capacities of strong auto-aggregation and high nitrogen removal efficiency were studied. The aggregation index analysis indicated that coaggregation of the three strains co-existed was better when compared with one or two strains grown alone. Optimal coaggregation strains were used to bioaugmente a test reactor (SBBRT), which exhibited a shorter time for biofilm-formation than uninoculated control reactor (SBBRC). With different influent ammonia-N loads (150, 200 and 300 mg·L[-1]), the average ammonia-N and nitrate-N removal efficiency were all higher than that in SBBRC, as well as a lower nitrite-N accumulation. Microbial community structure analysis revealed coaggregation strains may successfully colonize in the bioreactor and be very tolerant of high nitrogen concentrations, and contribute to the high efficiency of inorganic nitrogen-removal and biofilm-formation.}, } @article {pmid34139511, year = {2021}, author = {Nava-Ocampo, MF and Fuhaid, LA and Verpoorte, R and Choi, YH and van Loosdrecht, MCM and Vrouwenvelder, JS and Witkamp, GJ and Farinha, ASF and Bucs, SS}, title = {Natural deep eutectic solvents as biofilm structural breakers.}, journal = {Water research}, volume = {201}, number = {}, pages = {117323}, doi = {10.1016/j.watres.2021.117323}, pmid = {34139511}, issn = {1879-2448}, mesh = {*Extracellular Polymeric Substance Matrix ; *Plant Extracts ; Solvents ; Water ; }, abstract = {Natural Deep Eutectic Solvents (NADES) are composed of supramolecular interactions of two or more natural compounds, such as organic acids, sugars, and amino acids, and they are being used as a new media alternative to conventional solvents. In this study, a new application of NADES is presented as a possible technology for biofilm structural breaker in complex systems since the current solvents used for biofilm cleaning and extraction of biofilm components use hazardous solutions. The NADES (betaine:urea:water and lactic acid:glucose:water) were analyzed before and after the biofilm treatment by attenuated total reflection Fourier-transform infrared spectroscopy and fluorescence excitation-emission matrix spectroscopy. Our results indicate that the green solvents could solubilize up to ≈70 percent of the main components of the biofilms extracellular matrix. The solubilization of the biomolecules weakened the biofilm structure, which could enhance the biofilm solubilization and removal. The NADES have the potential to be an environment-friendly, green solvent to extract valuable compounds and break the main structure from the biofilm, leading to a greener method for extracellular polymeric substance (EPS) extraction and biofilm treatment in various water treatment systems.}, } @article {pmid34137898, year = {2021}, author = {Badie, F and Saffari, M and Moniri, R and Alani, B and Atoof, F and Khorshidi, A and Shayestehpour, M}, title = {The combined effect of stressful factors (temperature and pH) on the expression of biofilm, stress, and virulence genes in Salmonella enterica ser. Enteritidis and Typhimurium.}, journal = {Archives of microbiology}, volume = {203}, number = {7}, pages = {4475-4484}, pmid = {34137898}, issn = {1432-072X}, support = {3043//Kashan University of Medical Sciences/ ; }, mesh = {*Biofilms ; Hydrogen-Ion Concentration ; *Salmonella enteritidis/genetics/pathogenicity ; *Salmonella typhimurium/genetics/pathogenicity ; *Stress, Physiological/genetics ; *Temperature ; *Virulence/genetics ; }, abstract = {Salmonella enterica is a major food borne pathogen that creates biofilm. Salmonella biofilm formation under different environmental conditions is a public health problem. The present study was aimed to evaluate the combined effects of stressful factors (temperature and pH) on the expression of biofilm, stress, and virulence genes in Salmonella Enteritidis and Salmonella Typhimurium. In this study, the effect of temperature (2, 8, 22.5, 37, 43 °C) and pH (2.4, 3, 4.5, 6, 6.6) on the expression of biofilm production genes (adr A, bap A), virulence genes (hil A, inv A) and the stress gene (RpoS) of S. Enteritidis and S. Typhimurium was evaluated. The response surface methodology (RSM) approach was used to evaluate the combined effect of the above factors. The highest expression of adr A, bap A, hil A, and RpoS gene for S. Typhimurium was at 22 °C-pH 4.5 (6.39-fold increase), 37 °C-pH 6 (3.92-fold increase), 37 °C-pH 6 (183-fold increase), and 37 °C-pH 3 (43.8-fold increase), respectively. The inv A gene of S. Typhimurium was decreased in all conditions. The adr A, bap A, hil A, inv A, and RpoS gene of S. Enteritidis had the highest expression level at 8 °C-pH 3 (4.09-fold increase), 22 °C-pH 6 (2.71-fold increase), 8 °C pH 3 (190-fold increase), 22 °C-pH 4.5 (9.21-fold increase), and 8 °C-pH 3 (16.6-fold), respectively. Response surface methodology (RSM) indicated that the temperature and pH had no significant effect on the expression level of adr A, bap A, hil A, Inv A, and RpoS gene in S. Enteritidis and S. Typhimurium. The expression of biofilm production genes (adr A, bap A), virulence genes (hil A, inv A) and the stress gene (RpoS) of S. Enteritidis and S. Typhimurium is not directly and exclusively associated with temperature and pH conditions.}, } @article {pmid34136573, year = {2021}, author = {Baidya, S and Sharma, S and Mishra, SK and Kattel, HP and Parajuli, K and Sherchand, JB}, title = {Biofilm Formation by Pathogens Causing Ventilator-Associated Pneumonia at Intensive Care Units in a Tertiary Care Hospital: An Armor for Refuge.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {8817700}, pmid = {34136573}, issn = {2314-6141}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Bronchoalveolar Lavage ; Child ; Child, Preschool ; Cross-Sectional Studies ; *Drug Resistance, Multiple, Bacterial ; Female ; Gram-Negative Bacteria ; Humans ; Incidence ; Infant ; Infant, Newborn ; Intensive Care Units ; Intubation, Intratracheal ; Length of Stay ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Nepal ; Pneumonia, Ventilator-Associated/*microbiology ; Respiration, Artificial/adverse effects ; Tertiary Care Centers ; Young Adult ; }, abstract = {BACKGROUND: Emerging threat of drug resistance among pathogens causing ventilator-associated pneumonia (VAP) has resulted in higher hospital costs, longer hospital stays, and increased hospital mortality. Biofilms in the endotracheal tube of ventilated patients act as protective shield from host immunity. They induce chronic and recurrent infections that defy common antibiotics. This study intended to determine the biofilm produced by pathogens causing VAP and their relation with drug resistance.

METHODS: Bronchoalveolar lavage and deep tracheal aspirates (n = 70) were obtained from the patients mechanically ventilated for more than 48 hours in the intensive care units of Tribhuvan University Teaching Hospital, Kathmandu, and processed according to the protocol of the American Society for Microbiology (ASM). Antibiotic susceptibility testing was done following Clinical and Laboratory Standards Institute (CLSI) 2017 guidelines. Biofilm formation was determined using the microtiter plate method described by Christensen and modified by Stepanovoic et al.

RESULTS: Significant microbial growth was seen in 78.6% of the total samples with 52.7% monomicrobial, 45.5% polymicrobial, and 1.8% fungal infection. Among the 71 isolates obtained, bulk was gram-negative (n = 64, 90.1%). Pseudomonas aeruginosa (31.0%) was the predominant isolate followed by Acinetobacter calcoaceticus baumannii complex (16.9%), Klebsiella pneumoniae (16.9%), Citrobacter freundii (15.5%), Staphylococcus aureus (7.0%), Escherichia coli (5.6%), Citrobacter koseri (2.8%), Enterococcus faecalis (1.4%), Burkholderia cepacia complex (1.4%), and Candida albicans (1.4%). Of the total isolates, 56.3% were biofilm producers. Multidrug-resistant (MDR) organisms, extended-spectrum β-lactamase (ESBL), and metallo-β-lactamase (MBL) producers were preeminent among the biofilm producers. The highest producer of biofilm was P. aeruginosa (19.7%). Among gram-negative biofilm producers, 42.2% were MDR, 21.9% were ESBL producers, and 7.8% were MBL producers.

CONCLUSION: Gram-negative nonfermenter bacteria account for the bulk of nosocomial pneumonia. MDR, ESBL, and MBL production was preponderant among the biofilm producers. The rampant spread of drug resistance among biofilm producers is summoning novel interventions to combat multidrug resistance.}, } @article {pmid34136569, year = {2021}, author = {Mohammadi, F and Hemmat, N and Bajalan, Z and Javadi, A}, title = {Analysis of Biofilm-Related Genes and Antifungal Susceptibility Pattern of Vaginal Candida albicans and Non-Candida albicans Species.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {5598907}, pmid = {34136569}, issn = {2314-6141}, mesh = {Adult ; Amphotericin B/pharmacology ; Antifungal Agents/*chemistry ; *Biofilms ; Biomass ; Candida albicans/*pathogenicity ; Candida glabrata/drug effects ; Candidiasis, Vulvovaginal/*microbiology ; Drug Resistance, Fungal/drug effects ; Female ; Fluconazole/pharmacology ; Humans ; Itraconazole/pharmacology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Middle Aged ; Polymorphism, Restriction Fragment Length ; Vagina/*microbiology ; Virulence ; Voriconazole/pharmacology ; Young Adult ; }, abstract = {BACKGROUND: Vulvovaginal candidiasis caused by Candida species is a prevalent fungal infection among women. It is believed that the pathogenesis of Candida species is linked with the production of biofilm which is considered a virulence factor for this organism. The aim of this study was molecular identification, antifungal susceptibility, biomass quantification of biofilm, and detection of virulence markers of Candida species.

METHODS: We investigated the molecular identification of 70 vaginal isolates of Candida species, antifungal resistance to amphotericin B, fluconazole, itraconazole, and voriconazole according to CLSI M27-A3 and M27-S4, biofilm formation, and frequency analysis of biofilm-related ALS1, ALS3, and HWP1 genes.

RESULTS: Our findings showed that the most common yeast isolated from vaginal discharge was C. albicans (67%), followed by the non-Candida albicans species (33%). All C. albicans complex isolates were confirmed as C. albicans by HWP-PCR, and all isolates of the C. glabrata complex were revealed to be C. glabrata sensu stricto using the multiplex PCR method. FLC resistance was observed in 23.4% of C. albicans and 7.7% of C. glabrata. The resistance rate to ITC was found in 10.6% of C. albicans. The frequency of ALS1, ALS3, and HWP1 genes among Candida species was 67.1%, 80%, and 81.4%, respectively. Biofilm formation was observed in 54.3% of Candida species, and the highest frequency detected as a virulence factor was for the ALS3 gene (97.3%) in biofilm-forming species. Discussion. Our results showed the importance of molecular epidemiology studies, investigating antifungal susceptibility profiles, and understanding the role of biofilm-related virulence markers in the pathogenesis of Candida strains.}, } @article {pmid34135871, year = {2021}, author = {Liu, X and Ye, Y and Zhu, Y and Wang, L and Yuan, L and Zhu, J and Sun, A}, title = {Involvement of RpoN in Regulating Motility, Biofilm, Resistance, and Spoilage Potential of Pseudomonas fluorescens.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {641844}, pmid = {34135871}, issn = {1664-302X}, abstract = {Pseudomonas fluorescens is a typical spoiler of proteinaceous foods, and it is characterized by high spoilage activity. The sigma factor RpoN is a well-known regulator controlling nitrogen assimilation and virulence in many pathogens. However, its exact role in regulating the spoilage caused by P. fluorescens is unknown. Here, an in-frame deletion mutation of rpoN was constructed to investigate its global regulatory function through phenotypic and RNA-seq analysis. The results of phenotypic assays showed that the rpoN mutant was deficient in swimming motility, biofilm formation, and resistance to heat and nine antibiotics, while the mutant increased the resistance to H2O2. Moreover, the rpoN mutant markedly reduced extracellular protease and total volatile basic nitrogen (TVB-N) production in sterilized fish juice at 4°C; meanwhile, the juice with the rpoN mutant showed significantly higher sensory scores than that with the wild-type strain. To identify RpoN-controlled genes, RNA-seq-dependent transcriptomics analysis of the wild-type strain and the rpoN mutant was performed. A total of 1224 genes were significantly downregulated, and 474 genes were significantly upregulated by at least two folds at the RNA level in the rpoN mutant compared with the wild-type strain, revealing the involvement of RpoN in several cellular processes, mainly flagellar mobility, adhesion, polysaccharide metabolism, resistance, and amino acid transport and metabolism; this may contribute to the swimming motility, biofilm formation, stress and antibiotic resistance, and spoilage activities of P. fluorescens. Our results provide insights into the regulatory role of RpoN of P. fluorescens in food spoilage, which can be valuable to ensure food quality and safety.}, } @article {pmid34135604, year = {2021}, author = {Chen, L and Yu, K and Chen, L and Zheng, X and Huang, N and Lin, Y and Jia, H and Liao, W and Cao, J and Zhou, T}, title = {Synergistic Activity and Biofilm Formation Effect of Colistin Combined with PFK-158 Against Colistin-Resistant Gram-Negative Bacteria.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {2143-2154}, pmid = {34135604}, issn = {1178-6973}, abstract = {PURPOSE: The emergence of colistin resistance among Gram-negative bacteria (GNB) poses a serious public health threat. Therefore, it is necessary to enhance the antibacterial activity of colistin through the combination with other drugs. In this study, we demonstrated the synergistic activity and the possible synergy mechanism of colistin with PFK-158 against colistin-resistant GNB, including non-fermenting bacteria and Enterobacteriaceae.

PATIENTS AND METHODS: Thirty-one colistin-resistant GNB, including Pseudomonas aeruginosa (n = 9), Acinetobacter baumannii (n = 5), Escherichia coli (n = 8) and Klebsiella pneumoniae (n = 9), were collected as the experimental strains and the minimum inhibitory concentrations (MICs) of colistin, other routine antimicrobial agents and PFK-158 against all strains were determined by the broth microdilution method. The synergistic activity of colistin with PFK-158 was assessed by the checkerboard assay and time-kill assay. The biofilm formation assay and scanning electron microscopy were used to demonstrate the biofilm formation effect of colistin with PFK-158 against colistin-resistant GNB.

RESULTS: The results of the checkerboard assay showed that when colistin was used in combination with PFK-158, synergistic activity was observed against the 31 colistin-resistant GNB. The time-kill assay presented a significant killing activity of colistin with PFK-158 against the 9 colistin-resistant GNB selected randomly, including Pseudomonas aeruginosa (n = 6), Acinetobacter baumannii (n = 1), Escherichia coli (n = 1), and Klebsiella pneumoniae (n = 1). The biofilm formation assay and scanning electron microscopjihy showed that colistin with PFK-158 can effectively suppress the formation of biofilm and reduce the cell arrangement density of biofilm against most experimental strains.

CONCLUSION: The results of the performed experiments suggest that the combination of colistin and PFK-158 may be a potential new choice as a new antibiofilm group for the treatment of infections caused by the colistin-resistant GNB.}, } @article {pmid34135567, year = {2021}, author = {Mordmuang, A and Udomwech, L and Karnjana, K}, title = {Influence of Contact Lens Materials and Cleaning Procedures on Bacterial Adhesion and Biofilm Formation.}, journal = {Clinical ophthalmology (Auckland, N.Z.)}, volume = {15}, number = {}, pages = {2391-2402}, pmid = {34135567}, issn = {1177-5467}, abstract = {PURPOSE: The present study aimed to compare the existing soft contact lens (CL) materials regarding their influence on bacterial biofilm formation and adhesion susceptibility. Then, the study was designed to investigate the effectiveness of various disinfecting solutions and evaluate the ability of cleaning regimens in terms of anti-bacterial adhesion and biofilm removal on different soft CL materials.

METHODS: Bacterial biofilm formation on CLs was evaluated by biomass assay. Adhesion assay and standard plate count were carried out at time-interval periods within 24 h. Various CL disinfecting procedures were assessed for their efficacy to remove biofilm and reduce bacterial adhesion. Scanning electron microscopy (SEM) was performed for the morphological assessment of bacterial biofilm.

RESULTS: Printed hydroxyethyl methacrylate (HEMA) CLs significantly demonstrated more biofilm staining and bacterial attachment when compared with non-printed HEMA CLs, while the Filcon II 3 and Nesofilcon A CLs possessed less biofilm biomass and adherent cells. Staphylococcus aureus and Pseudomonas aeruginosa represented the highest biofilm producing bacteria on HEMA-based materials in this study. The disinfecting regimen with the highest efficacy was the two-step system, first using multipurpose disinfecting solution containing edetate disodium and sorbic acid (MPDS+EDSA), followed by soaking in multipurpose solution (MPS). The regimen demonstrated the greatest effect against the pre-formed biofilm and the adhesion activity of S. aureus and P. aeruginosa on the soft CLs. The SEM micrographs confirmed the morphological changes of bacterial biofilm after disinfecting and revealed that the two-step system treated CLs displayed less adherent bacteria.

CONCLUSION: HEMA-based soft CLs may facilitate bacterial biofilm formation and adhesion capability. The two-step system was the most effective regimen for biofilm removal, where the soaking period in the disinfecting solution of the no-rub regimen should last more than 6 h to remove pre-formed biofilm.}, } @article {pmid34133959, year = {2021}, author = {Shahmoradi, S and Shariati, A and Zargar, N and Yadegari, Z and Asnaashari, M and Amini, SM and Darban-Sarokhalil, D}, title = {Antimicrobial effects of selenium nanoparticles in combination with photodynamic therapy against Enterococcus faecalis biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {35}, number = {}, pages = {102398}, doi = {10.1016/j.pdpdt.2021.102398}, pmid = {34133959}, issn = {1873-1597}, mesh = {*Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; *Nanoparticles ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; *Selenium/pharmacology ; }, abstract = {BACKGROUND: Selenium Nanoparticles (SeNPs) were reported as an agent that may enhance the effectiveness of Photodynamic Antimicrobial Chemotherapy (PACT). This in vitro study evaluates the effect of SeNPs on the efficacy of Methylene Blue (MB)-induced PACT against the biofilm formated in 96-well plates and the dentine tubule biofilm of Enterococcus faecalis.

METHODS: Chitosan coated SeNPs were synthesized using chemical reduction method and were characterized by Transmission Electron Microscope (TEM) and Dynamic Light Scattering (DLS). Twenty-four-hour biofilms of E. faecalis were developed on 96-well plates and treated with SeNPs, MB, and Light-Emitting Diode (LED). Also, three-week biofilms of E. faecalis were formed on 67 specimens of dentinal tubules, and the antibacterial effects of MB+SeNPs on these biofilms were studied.

RESULTS: The average hydrodynamic diameter of SeNPs was 80/3 nm according to DLS measurement. The combined use of MB and SeNPs significantly reduced Colony-Forming Units (CFUs) of one-day-old E. faecalis biofilms in comparison with the control group (P value < 0.05). Besides, combination therapy had the most antibacterial effect on root canal E. faecalis biofilms at both 200 and 400 µm depths of dentine tubules (P value < 0.001). Of note, about 50% of human fibroblast cells survived at a concentration of 128 µg/ml of SeNPs, compared to the control group.

CONCLUSION: The results demonstrated that the photodynamic therapy modified by SeNPs could be an effective disinfection alternative to the destruction of E. faecalis biofilms and root canal treatment.}, } @article {pmid34133169, year = {2021}, author = {Vishwakarma, A and Dang, F and Ferrell, A and Barton, HA and Joy, A}, title = {Peptidomimetic Polyurethanes Inhibit Bacterial Biofilm Formation and Disrupt Surface Established Biofilms.}, journal = {Journal of the American Chemical Society}, volume = {}, number = {}, pages = {}, doi = {10.1021/jacs.1c02324}, pmid = {34133169}, issn = {1520-5126}, abstract = {Over 80% of all chronic bacterial infections in humans are associated with biofilms, which are surface-associated bacterial communities encased within a secreted exopolysaccharide matrix that can provide resistance to environmental and chemical insults. Biofilm formation triggers broad adaptive changes in the bacteria, allowing them to be almost 1000-fold more resistant to conventional antibiotic treatments and host immune responses. The failure of antibiotics to eliminate biofilms leads to persistent chronic infections and can promote the development of antibiotic-resistant strains. Therefore, there is an urgent need to develop agents that effectively prevent biofilm formation and eradicate established biofilms. Herein, we present water-soluble synthetic peptidomimetic polyurethanes that can disrupt surface established biofilms of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli, all of which show tolerance to the conventional antibiotics polymyxin B and ciprofloxacin. Furthermore, while these polyurethanes show poor antimicrobial activity against planktonic bacteria, they prevent surface attachment and stimulate bacterial surface motility to inhibit biofilm formation of both Gram-positive and Gram-negative bacteria at subinhibitory concentrations, without being toxic to mammalian cells. Our results show that these polyurethanes show promise as a platform for the development of therapeutics that target biofilms and modulate surface interactions of bacteria for the treatment of chronic biofilm-associated infections and as antibiofilm agents.}, } @article {pmid34131813, year = {2021}, author = {da Silva, DAL and de Melo Tavares, R and Camargo, AC and Yamatogi, RS and De Martinis, ECP and Nero, LA}, title = {Biofilm growth by Listeria monocytogenes on stainless steel and expression of biofilm-related genes under stressing conditions.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {7}, pages = {119}, pmid = {34131813}, issn = {1573-0972}, mesh = {Bacterial Adhesion ; Bacterial Proteins/*genetics ; Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; Culture Media/chemistry/*pharmacology ; Food Microbiology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Listeria monocytogenes/drug effects/genetics/*physiology ; Quaternary Ammonium Compounds/chemistry/pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Sodium Chloride/chemistry/pharmacology ; Stainless Steel/*chemistry ; Stress, Physiological ; }, abstract = {This research was carried out to investigate the differences in adhesion and growth during biofilm formation of L. monocytogenes from different sources and clonal complexes. Biofilm by L. monocytogenes (isolates CLIST 441 and 7: both lineage I, serotype 1/2b, CC3; isolates 19 and 508: both lineage II, serotype 1/2c, CC9) was grown on stainless steel coupons under different stressing conditions (NaCl, curing salts and quaternary ammonium compounds-QAC), to determine the expression of different genes involved in biofilm formation and stress response. CLIST 441, which carries a premature stop codon (PMSC) in agrC, formed high-density biofilms in the presence of QAC (7.5% w/v) or curing salts (10% w/v). Reverse Transcriptase-qPCR results revealed that L. monocytogenes isolates presented differences in transcriptional profile of genes related to biofilm formation and adaptation to environmental conditions. Our results demonstrated how L. monocytogenes can survive, multiply and form biofilm under adverse conditions related to food processing environments. Differences in transcriptional expression were observed, highlighting the role of regulatory gene networks for particular serotypes under different stress responses.}, } @article {pmid34131273, year = {2021}, author = {Liu, T and Aman, A and Ainiwaer, M and Ding, L and Zhang, F and Hu, Q and Song, Y and Ni, Y and Tang, X}, title = {Evaluation of the anti-biofilm effect of poloxamer-based thermoreversible gel of silver nanoparticles as a potential medication for root canal therapy.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {12577}, pmid = {34131273}, issn = {2045-2322}, support = {201715040//the Nanjing Foundation for Development of Science and Technology/ ; YKK16157//Nanjing Medical Science and Technique Development Foundation/ ; 20620140258、021414380009//the Fundamental Research Funds for the Central Universities of Nanjing University/ ; KFKT2018B16//State Key Lab. for Novel Software Technology(Nanjing University) foundation/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Calcium Hydroxide/chemistry ; Dental Pulp Cavity/drug effects/microbiology ; Enterococcus faecalis/drug effects/pathogenicity ; Female ; Humans ; Male ; Metal Nanoparticles/*chemistry ; Poloxamer/administration & dosage/*chemistry ; Root Canal Irrigants/*administration & dosage/chemistry ; Silver/chemistry ; }, abstract = {The purpose of this study was to design silver nanoparticles (AgNPs) poloxamer thermoreversible gel (AgNPs-PL) and investigate whether this gel could provide sustained antibacterial activity against Enterococcus faecalis (E. faecalis) in the root canal. The gels fabricated were characterized in terms of gelatin temperature, particle size, in-vitro Ag[+] release, and elemental content. Cytotoxicity of AgNPs-PL on primary human periodontal ligament fibroblasts (HPDLFs) was examined by CCK-8 assay. Characterization of AgNPs-PL gel revealed that it contained particles existing as large clumps/fused aggregates of different shapes, with a mean diameter of 21.624 ± 14.689 nm, exhibited sustained release of Ag[+] for 9 days, and non-toxic to HPDLFs at a low dose (4-32 μg/mL) through 24, 48, and 72 h exposures. The antibacterial effect of 16 and 32 μg/mL concentrations of AgNPs-PL was compared with blank poloxamer gel (PL) and calcium hydroxide (CH) using three methods: (I) agar counting plate, (II) scanning electron microscope (SEM) observations, and (III) confocal laser scanning microscope (CLSM) analysis. AgNPs-PL at the two doses above was more effective than PL and CH in removing E. faecalis biofilm at 1, 3, 9 days. Thus, AgNPs-PL exhibits strong activity against E. faecalis and is easy to produce, with a continuous release profile of Ag[+]. AgNPs-PL gel may be a candidate for a new root canal disinfection.}, } @article {pmid34130843, year = {2021}, author = {Shi, Y and Zhang, Y and Wu, X and Zhang, H and Yang, M and Tian, Z}, title = {Potential dissemination mechanism of the tetC gene in Aeromonas media from the aerobic biofilm reactor under oxytetracycline stresses.}, journal = {Journal of environmental sciences (China)}, volume = {105}, number = {}, pages = {90-99}, doi = {10.1016/j.jes.2020.12.038}, pmid = {34130843}, issn = {1001-0742}, mesh = {*Aeromonas/genetics ; Anti-Bacterial Agents ; Biofilms ; *Oxytetracycline ; Plasmids/genetics ; }, abstract = {The tetC gene has been found to be one of the most widely distributed tetracycline resistance (tet) genes in various environmental niches, but the detailed dissemination mechanisms are still largely unknown. In the present study, 11 tetC-containing Aeromonas media strains were isolated from an aerobic biofilm reactor under oxytetracycline stresses, and the genome of one strain was sequenced using the PacBio RSII sequencing approach to reveal the genetic environment of tetC. The tetC gene was carried by an IS26 composite transposon, named Tn6434. The tetC-carrying Tn6434 structure was detected in all of the A. media strains either in a novel plasmid pAeme2 (n=9) or other DNA molecules (n=2) by PCR screening. The NCBI database searching result shows that this structure was also present in the plasmids or chromosomes of other 13 genera, indicating the transferability of Tn6434. Inverse PCR and sequencing confirmed that Tn6434 can form a circular intermediate and is able to incorporate into a preexisting IS26 element, suggesting that Tn6434 might be responsible for the dissemination of tetC between different DNA molecules. This study will be helpful in uncovering the spread mechanism of tet genes in water environments.}, } @article {pmid34130464, year = {2021}, author = {Łusiak-Szelachowska, M and Weber-Dąbrowska, B and Żaczek, M and Górski, A}, title = {Anti-biofilm activity of bacteriophages and lysins in chronic rhinosinusitis.}, journal = {Acta virologica}, volume = {65}, number = {2}, pages = {127-140}, doi = {10.4149/av_2021_203}, pmid = {34130464}, issn = {0001-723X}, mesh = {Animals ; *Bacteriophages ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Mice ; Sheep ; *Sinusitis/therapy ; Staphylococcus aureus ; }, abstract = {Chronic rhinosinusitis (CRS) is an otolaryngological disease with a recalcitrant nature, predominantly due to antibiotic resistant bacteria and the biofilm formation. The intracellular residency of Staphylococcus aureus bacteria was observed in CRS. The overall prevalence of CRS is estimated between 5-15% in the human population, and biofilms were formed in sinuses in 40-80% of cases. The bacterial species S. aureus and Pseudomonas aeruginosa are known to form difficult to treat biofilms in CRS. Bacteriophages (phages) or lysins can be alternatives to antibiotics in the biofilm treatment. The application of a P. aeruginosa phage cocktail ex vivo decreased biofilm biomass of bacterial isolates from the sinuses of CRS patients by a median of 70%. Further, animal studies performed on a sheep sinusitis model demonstrated significant reduction in S. aureus and P. aeruginosa biofilm biomass by phage cocktails while maintaining safe prolonged topical application (up to 20 days). Staphylococcal lysin P128 used at a concentration of ≥12.5 µg/ml in vitro against the biofilm of methicillin sensitive S. aureus (MSSA) and methicillin resistant S. aureus (MRSA) isolates from the sinuses of CRS patients demonstrated a significant reduction of the biofilm (up to 95.5%). Staphylococcal lysin CHAP(k) applied in vivo in mice nasal infection caused a significant 2 log reduction of S. aureus suggesting its potential use against bacteria in nasal mucosa. Furthermore, a beneficial effect of phage therapy in the treatment of chronic sinusitis in humans was observed. Here, we summarize the recent, quite scarce data regarding phage application in chronic rhinosinusitis and look further into this phenomenon. Keywords: bacteriophages; biofilm; chronic rhinosinusitis; lysins; phage therapy.}, } @article {pmid34130233, year = {2021}, author = {Ji, B and Zhang, H and Zhou, L and Yang, J and Zhang, K and Yuan, X and Ma, J and Qian, Y}, title = {Effect of the rapid increase of salinity on anoxic-oxic biofilm reactor for treatment of high-salt and high-ammonia-nitrogen wastewater.}, journal = {Bioresource technology}, volume = {337}, number = {}, pages = {125363}, doi = {10.1016/j.biortech.2021.125363}, pmid = {34130233}, issn = {1873-2976}, mesh = {*Ammonia ; Biofilms ; Bioreactors ; Nitrification ; Nitrogen ; Salinity ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The washing wastewater from the desulfuration and denitration of power plants has high salt (chloride and sulfate) and ammonia-nitrogen concentrations and is difficult to treat using microbiological methods. A novel anoxic/oxic biofilm process was developed to remove ammonia from wastewater. Three rapid strategies (sulfate concentration was increased from 0 to 60 g/L in 6, 13, and 22 days (R1, R2, and R3, respectively)) were applied and produced biofilm with the same nitrification capacity as slow strategies (100-203 days). Excessive organics inhibited the nitrification capacity of the biofilm. R1 excelled at ammonia removal (from 30% to 95%, 70 mg/(L·d), with an effluent ammonia concentration of 4 mg/L) at 60 g/L salinity after the organic load was reduced. The content of extracellular polymeric substances in biofilm depended on its capacity to remove organics. Pseudomonas and Thauera were enriched in the three reactors. Controlling the organic load might prevent the sulfur cycle.}, } @article {pmid34128460, year = {2022}, author = {Primo, MGB and Tipple, AFV and Costa, DM and Guadagnin, SVT and Azevedo, AS and Leão-Vasconcelos, LSNO and Alfa, M and Vickery, K}, title = {Biofilm accumulation in new flexible gastroscope channels in clinical use.}, journal = {Infection control and hospital epidemiology}, volume = {43}, number = {2}, pages = {174-180}, doi = {10.1017/ice.2021.99}, pmid = {34128460}, issn = {1559-6834}, mesh = {Biofilms ; Disinfection/methods ; Endoscopes/microbiology ; *Equipment Contamination ; *Gastroscopes ; Humans ; }, abstract = {OBJECTIVE: Assess the accumulation of protein and biofilm on the inner surfaces of new flexible gastroscope (FG) channels after 30 and 60 days of patient use and full reprocessing.

DESIGN: Clinical use study of biofilm accumulation in FG channels.

SETTING: Endoscopy service of a public hospital.

METHODS: First, we tested an FG in clinical use before the implementation of a revised reprocessing protocol (phase 1 baseline; n = 1). After replacement of the channels by new ones and the implementation of the protocol, 3 FGs were tested after 30 days of clinical use (phase 2; n = 3) and 3 FGs were tested after 60 days of clinical use (phase 3; n = 3), and the same FGs were tested in phase 2 and 3. Their biopsy, air, water, and air/water junction channels were removed and subjected to protein testing (n = 21), bacteriological culture (n = 21), and scanning electron microscopy (SEM) (n = 28). Air-water junction channels fragments were subjected to SEM only.

RESULTS: For the FGs, the average number of uses and reprocessing cycles was 60 times. Extensive biofilm was detected in air, water, and air-water junction channels (n = 18 of 28). All channels (28 of 28) showed residual matter, and structural damage was identified in most of them (20 of 28). Residual protein was detected in the air and water channels of all FG evaluated (phases 1-3), except for 1 air channel from phase 2. Bacteria were recovered from 8 of 21 channels, most air or water channels.

CONCLUSIONS: The short time before damage and biofilm accumulation in the channels was evident and suggests that improving the endoscope design is necessary. Better reprocessing methods and channel maintenance are needed.}, } @article {pmid34126766, year = {2021}, author = {Willett, JLE and Dale, JL and Kwiatkowski, LM and Powers, JL and Korir, ML and Kohli, R and Barnes, AMT and Dunny, GM}, title = {Comparative Biofilm Assays Using Enterococcus faecalis OG1RF Identify New Determinants of Biofilm Formation.}, journal = {mBio}, volume = {12}, number = {3}, pages = {e0101121}, pmid = {34126766}, issn = {2150-7511}, support = {R01 AI122742/AI/NIAID NIH HHS/United States ; T32 AI055433/AI/NIAID NIH HHS/United States ; T32 GM136534/GM/NIGMS NIH HHS/United States ; UL1 TR002494/TR/NCATS NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Enterococcus faecalis/*genetics/*physiology ; Mutation ; }, abstract = {Enterococcus faecalis is a common commensal organism and a prolific nosocomial pathogen that causes biofilm-associated infections. Numerous E. faecalis OG1RF genes required for biofilm formation have been identified, but few studies have compared genetic determinants of biofilm formation and biofilm morphology across multiple conditions. Here, we cultured transposon (Tn) libraries in CDC biofilm reactors in two different media and used Tn sequencing (TnSeq) to identify core and accessory biofilm determinants, including many genes that are poorly characterized or annotated as hypothetical. Multiple secondary assays (96-well plates, submerged Aclar discs, and MultiRep biofilm reactors) were used to validate phenotypes of new biofilm determinants. We quantified biofilm cells and used fluorescence microscopy to visualize biofilms formed by six Tn mutants identified using TnSeq and found that disrupting these genes (OG1RF_10350, prsA, tig, OG1RF_10576, OG1RF_11288, and OG1RF_11456) leads to significant time- and medium-dependent changes in biofilm architecture. Structural predictions revealed potential roles in cell wall homeostasis for OG1RF_10350 and OG1RF_11288 and signaling for OG1RF_11456. Additionally, we identified growth medium-specific hallmarks of OG1RF biofilm morphology. This study demonstrates how E. faecalis biofilm architecture is modulated by growth medium and experimental conditions and identifies multiple new genetic determinants of biofilm formation. IMPORTANCE E. faecalis is an opportunistic pathogen and a leading cause of hospital-acquired infections, in part due to its ability to form biofilms. A complete understanding of the genes required for E. faecalis biofilm formation as well as specific features of biofilm morphology related to nutrient availability and growth conditions is crucial for understanding how E. faecalis biofilm-associated infections develop and resist treatment in patients. We employed a comprehensive approach to analysis of biofilm determinants by combining TnSeq primary screens with secondary phenotypic validation using diverse biofilm assays. This enabled identification of numerous core (important under many conditions) and accessory (important under specific conditions) biofilm determinants in E. faecalis OG1RF. We found multiple genes whose disruption results in drastic changes to OG1RF biofilm morphology. These results expand our understanding of the genetic requirements for biofilm formation in E. faecalis that affect the time course of biofilm development as well as the response to specific nutritional conditions.}, } @article {pmid34126368, year = {2021}, author = {Giorgi-Pérez, AM and Arboleda-Ordoñez, AM and Villamizar-Suárez, W and Cardeñosa-Mendoza, M and Jaimes-Prada, R and Rincón-Orozco, B and Niño-Gómez, ME}, title = {Biofilm formation and its effects on microbiologically influenced corrosion of carbon steel in oilfield injection water via electrochemical techniques and scanning electron microscopy.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {141}, number = {}, pages = {107868}, doi = {10.1016/j.bioelechem.2021.107868}, pmid = {34126368}, issn = {1878-562X}, mesh = {*Biofilms ; Carbon/*chemistry ; Corrosion ; Electrochemical Techniques/*methods ; Microscopy, Electron, Scanning/*methods ; Reproducibility of Results ; Spectrometry, X-Ray Emission ; Steel/*chemistry ; Water ; }, abstract = {In this study, changes in the electrochemical conditions of oil fields caused by biofilms with sulfate-reducing bacteria have been studied as they promote localized pitting damage, reservoir souring problems, and many other processes including well plugging that lead to increased production costs. Biofilm formation and its effects on 1020 carbon steel surfaces were evaluated in a discontinuous electrochemical reactor by using a bacterial consortium isolated from the injection water of a Colombian oil field. Sulfide concentration and pH values were observed to decrease, which was consistent with the exponential planktonic sulfate-reducing bacterial growth. The formation of a biofilm that adheres to a porous layer of corrosion products was identified using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The morphology of the films revealed the presence of the biofilm and corrosion product crystals. Open circuit potential presented a negative shift in the potential during the first 24 h in a biotic cell. Electrochemical impedance spectroscopy showed a change in the behavior of the resistive zone for both systems, a charge transfer trend in the abiotic cell, and a transformation of the charge transfer process to a diffusive process in the biotic cell after 48 h. The polarization resistance showed its lowest resistivity 74.95 Ω·cm[-2] during the first 48 h, while the corrosion rate was estimated as 3.37 mpy. This research contributes to the understanding of corrosion mechanisms in the metal-solution interface via detailed monitoring of biofilm growth.}, } @article {pmid34125278, year = {2021}, author = {Ma, F and Zhou, H and Yang, Z and Wang, C and An, Y and Ni, L and Liu, M and Wang, Y and Yu, L}, title = {Gene expression profile analysis and target gene discovery of Mycobacterium tuberculosis biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {12}, pages = {5123-5134}, pmid = {34125278}, issn = {1432-0614}, support = {2016YFD0501302//State's Key Project of Research and Development Plan/ ; 2017YFD0502200//State's Key Project of Research and Development Plan/ ; No. 81801972//the National Natural Science Foundation of China/ ; 20150101108JC//the Fund for Science and Technology Development of Jilin Province/ ; No. 2016444//the Project of the Education Department of Jilin Province/ ; 31172364//the National Natural Science Foundation of China/ ; }, mesh = {Biofilms ; Gene Expression Profiling ; Genetic Association Studies ; Humans ; *Mycobacterium tuberculosis/genetics ; Transcriptome ; *Tuberculosis ; }, abstract = {Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tuberculosis) is a fatal infectious disease to human health, and the drug tolerance and immune evasion of M. tuberculosis were reported to be related to its biofilm formation; however, the difficulty of M. tuberculosis biofilm culture and its unknown global mechanism impede its further research. Here, we developed a modified in vitro M. tuberculosis biofilm model with shorter culture time. Then we used Illumina RNA-seq technology to determine the global gene expression profile of M. tuberculosis H37Rv biofilms. Over 437 genes are expressed at significantly different levels in biofilm cells than in planktonic cells; among them, 153 were downregulated and 284 were upregulated. Go enrichment analysis and KEGG pathway analysis showed that genes involved in biosynthesis and metabolism of sulfur metabolism, steroid degradation, atrazine degradation, mammalian cell entry protein complex, etc. are involved in M. tuberculosis biofilm cells. Especially, ATP-binding cassette (ABC) transporters Rv1217c and Rv1218c were significantly upregulated in biofilm, whereas efflux pump inhibitors (EPIs) piperine and 1-(1-naphthylmethyl)-piperazine (NMP) inhibited biofilm formation and the expression of the Rv1217c and Rv1218c genes in a concentration-dependent manner, respectively, indicating Rv1217c and Rv1218c are potential target genes of M. tuberculosis biofilm. This study is the first RNA-Seq-based transcriptome profiling of M. tuberculosis biofilms and provides insights into a potential strategy for M. tuberculosis biofilm inhibition. KEY POINTS: • Characterize M. tuberculosis transcriptomes in biofilm cells by RNA-seq. • Inhibit the expression of Rv1217c and Rv1218c repressed biofilm formation.}, } @article {pmid34123878, year = {2021}, author = {Smolarz, M and Zawrotniak, M and Satala, D and Rapala-Kozik, M}, title = {Extracellular Nucleic Acids Present in the Candida albicans Biofilm Trigger the Release of Neutrophil Extracellular Traps.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {681030}, pmid = {34123878}, issn = {2235-2988}, mesh = {Biofilms ; Candida albicans ; *Extracellular Traps ; Humans ; Neutrophils ; *Nucleic Acids ; }, abstract = {Neutrophils, the first line of the host's defense, use a variety of antimicrobial mechanisms to fight invading pathogens. One of the most crucial is the production of neutrophil extracellular traps (NETs) in the process called NETosis. The unique structure of NETs effectively inhibits the spread of pathogens and ensures their exposure to a high concentration of NET-embedded antimicrobial compounds. NETosis strategy is often used by the host to defend against fungal infection caused by Candida albicans. In immunocompromised patients, this microorganism is responsible for developing systemic fungal infections (candidiasis). This is correlated with the use of a vast array of virulence factors, leading to the acquisition of specific resistance to host defense factors and available drug therapies. One of the most important features favoring the development of drug resistance is a C. albicans ability to form biofilms that protect fungal cells mainly through the production of an extracellular matrix (ECM). Among the main ECM-building macromolecules extracellular nucleic acids have been identified and their role is probably associated with the stbilization of the biofilm structure. The complex interactions of immune cells with the thick ECM layer, comprising the first line of contact between these cells and the biofilm structure, are still poorly understood. Therefore, the current studies aimed to assess the release of extracellular nucleic acids by C. albicans strains at different stages of biofilm formation, and to determine the role of these molecules in triggering the NETosis. We showed for the first time that fungal nucleic acids, purified directly from mature C. albicans biofilm structure or obtained from the whole fungal cells, have the potential to induce NET release in vitro. In this study, we considered the involvement of TLR8 and TLR9 in NETosis activation. We showed that DNA and RNA molecules initiated the production of reactive oxygen species (ROS) by activation of the NADPH oxidase complex, essential for ROS-dependent NETosis. Furthermore, analysis of the cell migration showed that the nucleic acids located in the extracellular space surrounding the biofilm may be also effective chemotactic factors, driving the dynamic migration of human neutrophils to the site of ongoing fungal infection.}, } @article {pmid34122552, year = {2021}, author = {El Othmany, R and Zahir, H and Ellouali, M and Latrache, H}, title = {Current Understanding on Adhesion and Biofilm Development in Actinobacteria.}, journal = {International journal of microbiology}, volume = {2021}, number = {}, pages = {6637438}, pmid = {34122552}, issn = {1687-918X}, abstract = {Biofilm formation and microbial adhesion are two related and complex phenomena. These phenomena are known to play an important role in microbial life and various functions with positive and negative aspects. Actinobacteria have wide distribution in aquatic and terrestrial ecosystems. This phylum is very large and diverse and contains two important genera Streptomyces and Mycobacteria. The genus Streptomyces is the most biotechnologically important, while the genus Mycobacteria contains the pathogenic species of Mycobacteriaceae. According to the literature, the majority of studies carried out on actinomycetes are focused on the detection of new molecules. Despite the well-known diversity and metabolic activities, less attention has been paid to this phylum. Research on adhesion and biofilm formation is not well developed. In the present review, an attempt has been made to review the literature available on the different aspects on biofilm formation and adhesion of Actinobacteria. We focus especially on the genus Streptomyces. Furthermore, a brief overview about the molecules and structures involved in the adhesion phenomenon in the most relevant genus is summarized. We mention the mechanisms of quorum sensing and quorum quenching because of their direct association with biofilm formation.}, } @article {pmid34122361, year = {2021}, author = {Hall, DC and Palmer, P and Ji, HF and Ehrlich, GD and Król, JE}, title = {Bacterial Biofilm Growth on 3D-Printed Materials.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {646303}, pmid = {34122361}, issn = {1664-302X}, support = {R01 DC002148/DC/NIDCD NIH HHS/United States ; }, abstract = {Recent advances in 3D printing have led to a rise in the use of 3D printed materials in prosthetics and external medical devices. These devices, while inexpensive, have not been adequately studied for their ability to resist biofouling and biofilm buildup. Bacterial biofilms are a major cause of biofouling in the medical field and, therefore, hospital-acquired, and medical device infections. These surface-attached bacteria are highly recalcitrant to conventional antimicrobial agents and result in chronic infections. During the COVID-19 pandemic, the U.S. Food and Drug Administration and medical officials have considered 3D printed medical devices as alternatives to conventional devices, due to manufacturing shortages. This abundant use of 3D printed devices in the medical fields warrants studies to assess the ability of different microorganisms to attach and colonize to such surfaces. In this study, we describe methods to determine bacterial biofouling and biofilm formation on 3D printed materials. We explored the biofilm-forming ability of multiple opportunistic pathogens commonly found on the human body including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus to colonize eight commonly used polylactic acid (PLA) polymers. Biofilm quantification, surface topography, digital optical microscopy, and 3D projections were employed to better understand the bacterial attachment to 3D printed surfaces. We found that biofilm formation depends on surface structure, hydrophobicity, and that there was a wide range of antimicrobial properties among the tested polymers. We compared our tested materials with commercially available antimicrobial PLA polymers.}, } @article {pmid34119625, year = {2021}, author = {Eladawy, M and El-Mowafy, M and El-Sokkary, MMA and Barwa, R}, title = {Antimicrobial resistance and virulence characteristics in ERIC-PCR typed biofilm forming isolates of P. aeruginosa.}, journal = {Microbial pathogenesis}, volume = {158}, number = {}, pages = {105042}, doi = {10.1016/j.micpath.2021.105042}, pmid = {34119625}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {Pseudomonas aeruginosa is a serious pathogen particularly in immunocompromised patients. In this work, 103 clinical isolates of P. aeruginosa were collected and classified into weak, moderate, and strong biofilm producers according to their biofilm forming abilities via tissue culture plate method. The antimicrobial resistance and the presence of different virulence genes were investigated via disc diffusion method and polymerase chain reaction respectively. Moreover, ERIC-PCR typing was performed to investigate the genetic diversity among the clinical isolates. No significant correlation was observed between biofilm formation and resistance to each antimicrobial agent. Similar observation was detected concerning the multidrug resistance and biofilm formation. Regarding virulence genes, algD gene was harbored by all isolates (100%). Only pelA and phzM were significantly prevalent in strong biofilm producers. Additionally, the mean virulence score was higher in strong biofilm producers (9.33) than moderate (8.62) and weak (7) biofilm producers. Moreover, there was a significant correlation between the overall virulence score of the isolates and its ability to form biofilm. ERIC-PCR genotyping revealed the presence of 99 different ERIC patterns based on 70% similarity, and the different ERIC patterns were categorized into 8 clusters. 100% similarity indicates the possibility of cross-colonization in P. aeruginosa infections.}, } @article {pmid34118626, year = {2021}, author = {Bhowmick, T and Sen, G and Mukherjee, J and Das, R}, title = {Assessing the effect of herbicide diuron on river biofilm: A statistical model.}, journal = {Chemosphere}, volume = {282}, number = {}, pages = {131104}, doi = {10.1016/j.chemosphere.2021.131104}, pmid = {34118626}, issn = {1879-1298}, mesh = {Biofilms ; Chlorophyll A ; *Diatoms ; Diuron/toxicity ; Ecosystem ; *Herbicides/toxicity ; Models, Statistical ; Rivers ; *Water Pollutants, Chemical/toxicity ; }, abstract = {River biofilm communities are the first ones to be exposed to all toxic discharges received via run off from agricultural fields. Hence, changes in river biofilm community structure and growth pattern are considered as indicator of overall health of lotic ecosystem. Toxicants have effect on biofilm biomass, photosynthetic efficiency and chlorophyll a concentrations. Mathematical models may be applied to estimate the overall vigor of riverine ecosystems considering biofilms as indicators. Herein, previous empirical data of Ricart et al. (2009) on long term effects of environmentally relevant concentrations of diuron on biofilm communities of the River Llobregat, Spain was considered as our model inputs. Our objective is to understand the influence of diuron, chlorophyll a concentrations and photosynthetic efficiency on biovolume using a statistical model. The non-linear relationships between biovolume (dependent variable) and diuron, chlorophyll a concentrations and photosynthetic efficiency (independent variables) were represented by constructing three separate basis functions based on day 8 empirical data. Biovolume, due to nonlinear influence as yielded by the basis functions were used in a multiple linear regression model to estimate the net biovolume. Model validation was done based on day 29 empirical data. The experimentally determined biovolume and our model estimated biovolume showed similar trends. Also, diuron and photosynthetic efficiency had significant (p < 0.05) influence on biovolume. Since, the predominance of diatoms as biofilms within periphytic layers is very common in lotic systems, estimation of changes in diatom biovolume will be significant to assess the effect of herbicides. Diatom biovolume of any day (for example day 22) mentioned in the experimental study may be determined by this model, without the requirement of tedious manual biovolume calculation. Our model will be useful in numerous other studies undertaken on the toxic effect of pollutants on biofilms to quickly and accurately estimate the biofilm biovolume.}, } @article {pmid34118536, year = {2021}, author = {Yadav, N and Govindwar, SP and Rane, N and Ahn, HJ and Xiong, JQ and Jang, M and Kim, SH and Jeon, BH}, title = {Insights on the role of periphytic biofilm in synergism with Iris pseudacorus for removing mixture of pharmaceutical contaminants from wastewater.}, journal = {Journal of hazardous materials}, volume = {418}, number = {}, pages = {126349}, doi = {10.1016/j.jhazmat.2021.126349}, pmid = {34118536}, issn = {1873-3336}, mesh = {Biofilms ; *Iris Plant ; Nitrogen/analysis ; *Pharmaceutical Preparations ; Wastewater ; }, abstract = {The potential of Iris pseudacorus and the associated periphytic biofilm for biodegradation of two common pharmaceutical contaminants (PCs) in urban wastewater was assessed individually and in consortium. An enhanced removal for sulfamethoxazole (SMX) was achieved in consortium (59%) compared to individual sets of I. pseudacorus (50%) and periphytic biofilm (7%) at concentration of 5 mg L[-1]. Conversely, individual sets of periphytic biofilm (77%) outperformed removal of doxylamine succinate (DOX) compared to individual sets of I. pseudacorus (59%) and consortium (67%) at concentration of 1 mg L[-1]. Enhanced relative abundance of microflora containing microalgae (Sellaphora, Achnanthidium), rhizobacteria (Acidibacter, Azoarcus, Thioalkalivibrio), and fungi (Serendipita) in periphytic biofilm was observed after treatment. SMX treatment for five days elevated cytochrome P450 enzymes' expressions, including aniline hydroxylase (48%) and aminopyrine N-demethylase (54%) in the periphytic biofilm. Nevertheless, I. pseudacorus showed 175% elevation of aniline hydroxylase along with other biotransformation enzymes, such as peroxidase (629%), glutathione S-transferase (514%), and dichloroindophenol reductase (840%). A floating bed phytoreactor planted with I. pseudacorus and the periphytic biofilm consortium removed 67% SMX and 72% DOX in secondary wastewater effluent. Thus, the implementation of this strategy in constructed wetland-based treatment could be beneficial for managing effluents containing PCs.}, } @article {pmid34118282, year = {2021}, author = {Marcato, RA and Garbelini, CCD and Danelon, M and Pessan, JP and Emerenciano, NG and Ishikawa, AS and Cannon, ML and Delbem, ACB}, title = {In situ evaluation of 200 ppm fluoride toothpaste content trimetaphosphate, xylitol and erythritol on enamel demineralization and dental biofilm.}, journal = {Journal of dentistry}, volume = {111}, number = {}, pages = {103724}, doi = {10.1016/j.jdent.2021.103724}, pmid = {34118282}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cariostatic Agents/pharmacology ; Cattle ; Cross-Over Studies ; Dental Enamel ; Double-Blind Method ; Erythritol ; Fluorides/pharmacology ; Hardness ; Humans ; *Tooth Demineralization/prevention & control ; *Toothpastes/pharmacology ; Xylitol/pharmacology ; }, abstract = {OBJECTIVE: To evaluate the effect of low-fluoride (F[-]) toothpaste and sodium trimetaphosphate (TMP) associated with xylitol and erythritol (XE) on enamel demineralization and biofilm composition.

METHODS: This crossover double-blind in situ study consisted of five phases (seven days each), in which 14 volunteers wore oral appliances containing four enamel bovine blocks. The cariogenic challenge was performed by exposure to a 30% sucrose solution (6x/day). The toothpaste treatments (3x/day) were as follows: placebo (no F[-]/TMP/XE); 200 ppm F[-] (NaF) (200F); 1,100 ppm F[-] (1100F); 16% Xylitol and 4% Erythritol (XE); and 200 ppm F[-], 0.2% TMP, 16% xylitol, and 4% erythritol (200F-TMP-XE). Percentage of surface hardness loss (%SH) and integrated loss of subsurface hardness (ΔKHN), and calcium (Ca[2+]), phosphate (PO4[3-]), and F[-] on enamel and biofilm were determined; as well as insoluble extracellular polysaccharide (EPS).

RESULTS: XE and 1100F groups showed no significant difference for %SH and ΔKHN values (p = 0.220 and p = 0.886), and the 200F-TMP-XE group had the lowest mineral loss (p < 0.001). Ca[2+] and PO4[3-] in the enamel showed the highest values (p < 0.001) for the 200F-TMP-XE group. Higher values of F[-] in the enamel and biofilm were observed for the 1100F group (p < 0.001). There was no difference for Ca[2+] (p = 1.00) and EPS (p =0.918) values between XE and 200-TMP-XE groups in the biofilm, but their values were higher and lower than the 1100F (p = 0.002 and p = 0.029), respectively.

CONCLUSIONS: 200F-TMP-XE promoted a greater protective effect against enamel demineralization and significantly affected the composition of biofilm formed in situ compared to 1100F toothpaste.

CLINICAL SIGNIFICANCE: Low-F[-] toothpaste containing TMP and polyols can be considered an effective and safe measure to improve the oral health of individuals, especially patients with high caries activity.}, } @article {pmid34117842, year = {2021}, author = {Birk, SE and Serioli, L and Cavallo, V and Haagensen, JAJ and Molin, S and Nielsen, LH and Zór, K and Boisen, A}, title = {Enhanced Eradication of Mucin-Embedded Bacterial Biofilm by Locally Delivered Antibiotics in Functionalized Microcontainers.}, journal = {Macromolecular bioscience}, volume = {21}, number = {8}, pages = {e2100150}, doi = {10.1002/mabi.202100150}, pmid = {34117842}, issn = {1616-5195}, mesh = {*Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Microbial Sensitivity Tests ; *Mucins ; Pseudomonas aeruginosa ; }, abstract = {Bacterial biofilm-related infections are difficult to eradicate and require repeated treatments with high doses of antibiotics. Thus, there is an urgent need for new treatment strategies that minimize the use of antibiotics while enhancing biofilm eradication. Functionalized reservoir-based microdevices, such as, microcontainers (MCs), offer, high drug loading capacity, mucus embedment, and tuneable drug release. Here, MCs are loaded with the antibiotic ciprofloxacin (CIP), and sealed with a lid consisting of chitosan (CHI) and a mucolytic agent, N-acetylcysteine (NAC). It is found that CHI and NAC work synergistically, showing improved mucoadhesive and mucolytic properties. To better mimic the in vivo habitat of Pseudomonas aeruginosa (P. aeruginosa), the biofilm is grown in a mucin-containing medium on a newly developed centrifugal microfluidic system. The CHI/NAC coated MCs improve eradication of biofilm (88.22 ± 2.89%) compared to CHI-coated MCs (72.68 ± 3.73%) or bolus injection (39.86 ± 13.28%). The findings suggest that MCs are significantly more efficient than a bolus treatment. Furthermore, CHI/NAC functionalized MCs kill most of the biomass already after 5 h (80.75 ± 3.50%), mainly due to a fast drug release. This is the first time that CHI/NAC has been combined as a coating to explore mucolytic properties on bacterial biofilms.}, } @article {pmid34117070, year = {2021}, author = {Ozer, E and Yaniv, K and Chetrit, E and Boyarski, A and Meijler, MM and Berkovich, R and Kushmaro, A and Alfonta, L}, title = {An inside look at a biofilm: Pseudomonas aeruginosa flagella biotracking.}, journal = {Science advances}, volume = {7}, number = {24}, pages = {}, pmid = {34117070}, issn = {2375-2548}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Flagella/genetics ; *Pseudomonas aeruginosa/genetics ; }, abstract = {The opportunistic pathogen, Pseudomonas aeruginosa, a flagellated bacterium, is one of the top model organisms for biofilm studies. To elucidate the location of bacterial flagella throughout the biofilm life cycle, we developed a new flagella biotracking tool. Bacterial flagella were site-specifically labeled via genetic code expansion. This enabled us to track bacterial flagella during biofilm maturation. Live flagella imaging revealed the presence and synthesis of flagella throughout the biofilm life cycle. To study the possible role of flagella in a biofilm, we produced a flagella knockout strain and compared its biofilm to that of the wild-type strain. Results showed a one order of magnitude stronger biofilm structure in the wild type in comparison with the flagella knockout strain. This suggests a possible structural role for flagella in a biofilm, conceivably as a scaffold. Our findings suggest a new model for biofilm maturation dynamic which underscores the importance of direct evidence from within the biofilm.}, } @article {pmid34116444, year = {2021}, author = {Vitorino, I and Albuquerque, L and Wiegand, S and Kallscheuer, N and da Costa, MS and Lobo-da-Cunha, A and Jogler, C and Maria Lage, O}, title = {Corrigendum to "Alienimonas chondri sp. nov., a novel planctomycete isolated from the biofilm of the red alga Chondrus crispus" [Syst. Appl. Microbiol. 43 (2020) 126083].}, journal = {Systematic and applied microbiology}, volume = {44}, number = {4}, pages = {126219}, doi = {10.1016/j.syapm.2021.126219}, pmid = {34116444}, issn = {1618-0984}, } @article {pmid34115788, year = {2021}, author = {Haiat, A and Ngo, HC and Samaranayake, LP and Fakhruddin, KS}, title = {The effect of the combined use of silver diamine fluoride and potassium iodide in disrupting the plaque biofilm microbiome and alleviating tooth discoloration: A systematic review.}, journal = {PloS one}, volume = {16}, number = {6}, pages = {e0252734}, pmid = {34115788}, issn = {1932-6203}, mesh = {Biofilms/*drug effects ; Dental Plaque/*drug therapy/microbiology ; Drug Combinations ; Fluorides, Topical/administration & dosage/pharmacology/therapeutic use ; Humans ; Microbiota ; Potassium Iodide/administration & dosage/pharmacology/*therapeutic use ; Quaternary Ammonium Compounds/administration & dosage/pharmacology/*therapeutic use ; Silver Compounds/administration & dosage/pharmacology/*therapeutic use ; Tooth Discoloration/*drug therapy/microbiology ; }, abstract = {Silver diamine fluoride (SDF) is used in minimally invasive dentistry for arresting dental caries. However, discoloration of teeth is a significant side effect that has limited the use of SDF. Hence, the application of potassium iodide (KI) following SDF has been proposed to ameliorate the staining. Although antimicrobial activity is one of the major mechanisms of the caries-arresting effect of SDF, the antimicrobial potency of SDF/KI combination is unclear. Thus, the primary objective of this systematic review was to appraise the studies on the antimicrobial efficacy of SDF/KI combination on cariogenic microbes. The secondary objective was to summarize the evidence on the potential of KI in reducing the discoloration associated with the application of SDF. Electronic databases of Medline via PubMed, Cochrane Library, Web of Science, and EBSCO host were searched for English language manuscripts from January 2005 to 15th November 2020. The reference lists of these manuscripts were manually searched for additional studies. Twelve studies were included in the final analysis, seven of which have investigated the antimicrobial efficacy of SDF/KI, and the rest have examined the anti-staining potential of KI. The exploratory findings from the reviewed articles revealed the promising antimicrobial potential of SDF/KI on cariogenic microbes associated with dentine caries. There is, however, contradictory evidence on the effect of SDF/KI on tooth color. The reviewed in-vitro studies indicated significant effectiveness of KI in preventing staining. A clinical trial on primary dentition showed 25% reduction in the incidence of staining by SDF after applying KI, while a clinical study on root caries in adults showed no significant effect. Within the methodological limitations of this review, we conclude that for arresting dental caries, SDF could be combined with KI, as there may be a lower likelihood of staining. Further, well-designed clinical trials on the antimicrobial and anti-staining effect of SDF/KI are needed to obtain more robust evidence.}, } @article {pmid34115063, year = {2021}, author = {Asmarz, HY and Magrin, GL and Prado, AM and Passoni, BB and Magalhães Benfatti, CA}, title = {Evaluation of Removal Torque and Internal Surface Alterations in Frictional Morse Taper Connections After Mechanical Loading Associated or Not with Oral Biofilm.}, journal = {The International journal of oral & maxillofacial implants}, volume = {36}, number = {3}, pages = {492-501}, doi = {10.11607/jomi.8483}, pmid = {34115063}, issn = {1942-4434}, mesh = {Biofilms ; Dental Abutments ; *Dental Implant-Abutment Design ; *Dental Implants ; Dental Stress Analysis ; Humans ; Materials Testing ; Torque ; }, abstract = {PURPOSE: To evaluate the abutment removal torque and the morphologic aspects of wear in frictional Morse taper connections after axial loading with or without biofilm immersion.

MATERIALS AND METHODS: Thirty sets of Morse taper implants and prosthetic abutments were divided into six groups based on the number of mechanical loading cycles and immersion in biofilm derived from human saliva: without load, without biofilm; without load, with biofilm; 100,000 cycles of load, without biofilm; 100,000 cycles of load, with biofilm; 500,000 cycles of load, without biofilm; and 500,000 cycles of load, with biofilm. Mechanical loading was applied at a force of 80 ± 15 N with a frequency of 2 Hz for 100,000 or 500,000 cycles. After removal torque evaluation, the internal surface of the implants was evaluated by scanning electron microscopy and optical profilometer. The results were statistically analyzed at a significance level of P = .05.

RESULTS: Overall, the removal torque increased for samples submitted to loading (100,000 cycles of load, without biofilm = 83.8 ± 15.8 Ncm; 100,000 cycles of load, with biofilm = 160.6 ± 16.2 Ncm; 500,000 cycles of load, without biofilm = 147.0 ± 29.3 Ncm; 500,000 cycles of load, with biofilm = 154.5 ± 14.0 Ncm) compared to samples without loading (without load, without biofilm = 23.0 ± 9.4 Ncm; without load, with biofilm = 27.2 ± 7.5 Ncm). The removal torque was not different between groups that received the same number of loading cycles and varied on biofilm exposure (P > .05). However, samples immersed in biofilm showed higher values of removal torque. Surface analysis revealed that the damage on the internal surface of implants was lower in samples not submitted to cyclic mechanical loading (P < .05) independently of immersion in biofilm medium.

CONCLUSION: Cyclic mechanical load on the frictional implant-abutment connection of Morse taper implants increased the removal torque of abutments. The findings of this research suggest that the presence of biofilm can potentially increase the removal torque in frictional Morse taper connections, although more studies are recommended to support this affirmation. Oral biofilm did not interfere with the presence of wear areas along the internal surface of Morse taper implants but increased the roughness values.}, } @article {pmid34112397, year = {2021}, author = {Jiang, X and Ren, S and Geng, Y and Jiang, C and Liu, G and Wang, H and Yu, T and Liang, Y}, title = {Role of the VirSR-VirAB system in biofilm formation of Listeria monocytogenes EGD-e.}, journal = {Food research international (Ottawa, Ont.)}, volume = {145}, number = {}, pages = {110394}, doi = {10.1016/j.foodres.2021.110394}, pmid = {34112397}, issn = {1873-7145}, mesh = {Bacterial Proteins ; Biofilms ; Food Handling ; *Listeria monocytogenes ; }, abstract = {The ability of Listeria monocytogenes, an important foodborne pathogen, to form biofilms in food processing environments leads to increased opportunity for contamination of food products, which is a major concern for food safety. In this study, the role of a complex system composed of the VirSR two-component signal transduction system (TCS) and the ATP-binding cassette (ABC) transporter VirAB in biofilm formation of L. monocytogenes EGD-e was investigated. Biofilm formation was measured using the microplate assay with crystal violet staining, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and attachment and swarming motility were compared between strain EGD-e and its isogenic deletion mutants. Additionally, the relative expression levels of genes associated with the early steps of biofilm development in the wild-type and mutant strains were also determined by RT-qPCR. Results from microplate assay, CLSM and SEM showed that VirR is not required for biofilm formation in L. monocytogenes EGD-e. A central finding of this study is that both VirAB and VirS are essential for biofilm formation and they could function as a whole in biofilm formation of L. monocytogenes EGD-e. The results also demonstrated that both VirAB and VirS are involved in attachment, but they are not associated with swarming motility. Results from RT-qPCR showed that flaA, motA and motB were downregulated in the mutant strains ΔvirAB and ΔvirS, which could be the possible reason for reduced attachment and biofilm formation in these mutants. This study provides a better understanding of the mechanisms involved in biofilm formation of L. monocytogenes, leading to improved processes to control this biofilm-forming foodborne pathogen.}, } @article {pmid34111440, year = {2021}, author = {Harb, M and Zarei-Baygi, A and Wang, P and Sawaya, CB and McCurry, DL and Stadler, LB and Smith, AL}, title = {Antibiotic transformation in an anaerobic membrane bioreactor linked to membrane biofilm microbial activity.}, journal = {Environmental research}, volume = {200}, number = {}, pages = {111456}, doi = {10.1016/j.envres.2021.111456}, pmid = {34111440}, issn = {1096-0953}, mesh = {Anaerobiosis ; Anti-Bacterial Agents ; Biofilms ; Bioreactors ; *Sewage ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {Although extensive research to date has focused on enhancing removal rates of antibiotics from municipal wastewaters, the transformation products formed by anaerobic treatment processes remain understudied. The present work aims to examine the possible roles that the different microbial communities of an anaerobic membrane bioreactor (AnMBR) play in the transformation of antibiotics during wastewater treatment. As part of this work, sulfamethoxazole, erythromycin, and ampicillin were added in separate stages to the influent of the AnMBR at incremental concentrations of 10, 50, and 250 μg/L each. Antibiotic-specific transformation products detected during each stage, as identified by high resolution LC-MS, are reported herein. Results suggest that both isoxazole (sulfamethoxazole) and β-lactam (ampicillin) ring opening could be facilitated by the AnMBR's bioprocess. Microbial community analysis results indicated that relative activity of the system's suspended biomass consistently shifted towards syntrophic groups throughout the duration of the experiment. Notable differences were also observed between the suspended biomass and the AnMBR's membrane biofilms. Membrane-attached biofilm communities showed high relative activities of several specific methanogenic (Methanothrix and Methanomethylovorans), syntrophic (Syntrophaceae), and sulfate-reducing (Desulfomonile) groups. Such groups have been previously identified as involved in the formation of the antibiotic degradation products observed in the effluent of the AnMBR. The activity of these communities within the biofilms likely confers certain advantages that aid in the biotransformation of the antibiotics tested.}, } @article {pmid34111239, year = {2021}, author = {Oliveira, DC and Thomson, JJ and Alhabeil, JA and Toma, JM and Plecha, SC and Pacheco, RR and Cuevas-Suárez, CE and Piva, E and Lund, RG}, title = {In vitro Streptococcus mutans adhesion and biofilm formation on different esthetic orthodontic archwires.}, journal = {The Angle orthodontist}, volume = {91}, number = {6}, pages = {786-793}, pmid = {34111239}, issn = {1945-7103}, mesh = {Biofilms ; Dental Alloys ; Esthetics, Dental ; Materials Testing ; *Orthodontic Wires ; *Streptococcus mutans ; Surface Properties ; }, abstract = {OBJECTIVES: To evaluate the ability of different esthetic archwires to retain oral biofilms in vitro.

MATERIALS AND METHODS: Seven different brands of coated orthodontic archwires were tested: two epoxy coated, two polytetrafluoroethylene coated, two rhodium coated, and one silver plus polymer coated. Conventional uncoated metallic archwires were used as controls. Streptococus mutans adherence to archwires was quantified by colony count following 24 hours of biolfilm growth, and total wire-associated biofilm was measured using a crystal violet staining assay. For both tests, two conditions were used: 0% sucrose and 3% sucrose. For statistical analysis, P < .05 was considered as statistically significant.

RESULTS: For S. mutans colony forming units per biofilm, there were no statistically significant differences among the various archwires (P = .795 for 0% sucrose; P = .905 for 3% sucrose). Regarding total biofilm formed on archwires in the 3% sucrose condition, there were statistically significant differences in crystal violet staining only for the comparison between Niti Micro Dental White and Copper Ni-Ti wires (P < .05).

CONCLUSIONS: The clinical use of esthetic-coated orthodontic wires may be considered to have similar risks as uncoated archwires for biofilm retention.}, } @article {pmid34110520, year = {2021}, author = {Khaleghi, M and Khorrami, S}, title = {Down-regulation of biofilm-associated genes in mecA-positive methicillin-resistant S. aureus treated with M. communis extract and its antibacterial activity.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {85}, pmid = {34110520}, issn = {2191-0855}, abstract = {Considering the prevalence of resistance to antibiotics, the discovery of effective agents against resistant pathogens is of extreme urgency. Herein, 26 mecA-positive methicillin-resistant S. aureus (MRSA) isolated from clinical samples were identified, and their resistance to 11 antibiotics was investigated. Next, the antibacterial and anti-biofilm activity of the ethanolic extract of M. communis on these strains was evaluated. Furthermore, the effect of this extract on the expression of biofilm-associated genes, icaA, icaD, bap, sarA, and agr, was studied. According to the results, all isolated strains were multidrug-resistant and showed resistance to oxacillin and tetracycline. Also, 96.15 and 88.46 % of them were resistant to gentamicin and erythromycin. However, the extract could effectively combat the strains. The minimum inhibitory concentration (MIC) against different strains ranged from 1.56 to 25 mg/ml and the minimum bactericidal concentration (MBC) was between 3.125 and 50 mg/ml. Even though most MRSA (67 %) strongly produced biofilm, the sub-MIC concentration of the extract destroyed the pre-formed biofilm and affected the bacterial cells inside the biofilm. It could also inhibit biofilm development by significantly decreasing the expression of icaA, icaD, sarA and bap genes involved in biofilm formation and development. In conclusion, the extract inhibits biofilm formation, ruins pre-formed biofilm, and kills cells living inside the biofilm. Furthermore, it down-regulates the expression of necessary genes and nips the biofilm formation in the bud.}, } @article {pmid34109159, year = {2021}, author = {Nag, M and Lahiri, D and Sarkar, T and Ghosh, S and Dey, A and Edinur, HA and Pati, S and Ray, RR}, title = {Microbial Fabrication of Nanomaterial and Its Role in Disintegration of Exopolymeric Matrices of Biofilm.}, journal = {Frontiers in chemistry}, volume = {9}, number = {}, pages = {690590}, pmid = {34109159}, issn = {2296-2646}, abstract = {Bacterial biofilms are responsible for the development of various chronic wound-related and implant-mediated infections and confer protection to the pathogenic bacteria against antimicrobial drugs and host immune responses. Hence, biofilm-mediated chronic infections have created a tremendous burden upon healthcare systems worldwide. The development of biofilms upon the surface of medical implants has resulted in the failure of various implant-based surgeries and therapies. Although different conventional chemical and physical agents are used as antimicrobials, they fail to kill the sessile forms of bacterial pathogens due to the resistance exerted by the exopolysaccharide (EPS) matrices of the biofilm. One of the major techniques used in addressing such a problem is to directly check the biofilm formation by the use of novel antibiofilm materials, local drug delivery, and device-associated surface modifications, but the success of these techniques is still limited. The immense expansion in the field of nanoscience and nanotechnology has resulted in the development of novel nanomaterials as biocidal agents that can be either easily integrated within biomaterials to prevent the colonization of microbial cells or directly approach the pathogen overcoming the biofilm matrix. The antibiofilm efficacies of these nanomaterials are accomplished by the generation of oxidative stresses and through alterations of the genetic expressions. Microorganism-assisted synthesis of nanomaterials paved the path to success in such therapeutic approaches and is found to be more acceptable for its "greener" approach. Metallic nanoparticles functionalized with microbial enzymes, silver-platinum nanohybrids (AgPtNHs), bacterial nanowires, superparamagnetic iron oxide (Fe3O4), and nanoparticles synthesized by both magnetotactic and non-magnetotactic bacteria showed are some of the examples of such agents used to attack the EPS.}, } @article {pmid34108950, year = {2021}, author = {Judan Cruz, KG and Alfonso, ED and Fernando, SID and Watanabe, K}, title = {Candida albicans Biofilm Inhibition by Ethnobotanicals and Ethnobotanically-Synthesized Gold Nanoparticles.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {665113}, pmid = {34108950}, issn = {1664-302X}, abstract = {The virulence and drug resistance of globally prevalent Candida albicans has presented complications toward its control while advances in effective antivirulence drugs remain critical. Emerging methods are now being evaluated to facilitate development of novel therapeutic approaches against this pathogen. This study focuses on the biofilm formation inhibition of ethnobotanical crude extracts and the use of nanotechnology through the ethnobotanically-synthesized gold nanoparticles to control C. albicans. Control on biofilm formation was compared using crude extracts (CEs) and biologically synthesized gold nanoparticles (CEs + AuNPs). Significantly lower biofilm formation was exhibited in thirteen (13) CEs and fourteen (14) CEs + AuNPs. Biofilm-linked genes Bcr1 and HSP90 expression were consequently downregulated. Higher biofilm inhibition activity was noted in some CEs + AuNPs compared to its counterpart CEs. This study emphasizes the biofilm inhibition activity of ethnobotanicals and the use of nanoparticles to enhance delivery of compounds, and points to its prospects for developing anti-pathogenic drugs without evolving resistance.}, } @article {pmid34106516, year = {2021}, author = {Janež, N and Škrlj, B and Sterniša, M and Klančnik, A and Sabotič, J}, title = {The role of the Listeria monocytogenes surfactome in biofilm formation.}, journal = {Microbial biotechnology}, volume = {14}, number = {4}, pages = {1269-1281}, pmid = {34106516}, issn = {1751-7915}, support = {J4-1771//Javna Agencija za Raziskovalno Dejavnost RS/ ; N2-0078//Javna Agencija za Raziskovalno Dejavnost RS/ ; P4-0116//Javna Agencija za Raziskovalno Dejavnost RS/ ; P4-0127//Javna Agencija za Raziskovalno Dejavnost RS/ ; }, mesh = {Biofilms ; Cell Wall ; Food Handling ; *Listeria monocytogenes/genetics ; }, abstract = {Listeria monocytogenes is a highly pathogenic foodborne bacterium that is ubiquitous in the natural environment and capable of forming persistent biofilms in food processing environments. This species has a rich repertoire of surface structures that enable it to survive, adapt and persist in various environments and promote biofilm formation. We review current understanding and advances on how L. monocytogenes organizes its surface for biofilm formation on surfaces associated with food processing settings, because they may be an important target for development of novel antibiofilm compounds. A synthesis of the current knowledge on the role of Listeria surfactome, comprising peptidoglycan, teichoic acids and cell wall proteins, during biofilm formation on abiotic surfaces is provided. We consider indications gained from genome-wide studies and discuss surfactome structures with established mechanistic aspects in biofilm formation. Additionally, we look at the analogies to the species L. innocua, which is closely related to L. monocytogenes and often used as its model (surrogate) organism.}, } @article {pmid34105845, year = {2021}, author = {Chen, X and Lorenzen, J and Xu, Y and Jonikaite, M and Thaarup, IC and Bjarnsholt, T and Kirketerp-Møller, K and Thomsen, TR}, title = {A novel chronic wound biofilm model sustaining coexistence of Pseudomonas aeruginosa and Staphylococcus aureus suitable for testing of antibiofilm effect of antimicrobial solutions and wound dressings.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {29}, number = {5}, pages = {820-829}, pmid = {34105845}, issn = {1524-475X}, mesh = {Bandages ; Biofilms ; Humans ; *Pseudomonas aeruginosa ; Staphylococcus aureus ; Wound Healing ; *Wound Infection/drug therapy ; }, abstract = {Chronic wounds are a large burden to patients and healthcare systems. Biofilm infections in chronic wounds are crucial factors leading to non-healing of wounds. It is important to study biofilm in wounds and to develop effective interventions against wound biofilm. This study presents a novel in vitro biofilm model mimicking infected chronic wounds. The novel layered chronic wound biofilm model uses woundlike media and includes both Pseudomonas aeruginosa and Staphylococcus aureus, which have been identified as the most important pathogens in wounds. The model sustains their coexistence for at least 96 h. Microscopy of the model revealed microbial growth in non-surface attached microcolonies as previously observed in vivo. The model was used to determine log10 -reduction for the use of an antimicrobial solution and antimicrobial dressings (containing silver or honey) showing moderate-to-low antibiofilm effect, which indicates better concordance with the observed clinical performance of this type of treatment than other widely used standard tests.}, } @article {pmid34105836, year = {2021}, author = {Kurt, A and Özyurt, E and Topcuoğlu, N}, title = {Effect of different beverages on surface properties and cariogenic biofilm formation of composite resin materials.}, journal = {Microscopy research and technique}, volume = {84}, number = {12}, pages = {2936-2946}, doi = {10.1002/jemt.23852}, pmid = {34105836}, issn = {1097-0029}, support = {TUBAP 2019/234//Scientific Research Fund of Trakya University/ ; }, mesh = {*Beverages ; Biofilms ; *Composite Resins ; Materials Testing ; Surface Properties ; }, abstract = {The consumption of certain beverages may affect the physical and biological properties of resin composites (RCs) according to type. This in vitro study aimed to evaluate the surface properties and cariogenic biofilm formation in microhybrid and nanohybrid RCs after immersion in different beverages. The effects of four beverages (distilled water-control, tea, coffee, and cola) on two RCs (microhybrid and nanohybrid) were evaluated. Changes in the surface properties were evaluated for each group using surface roughness measurement (n = 10), scanning electron microscopy (SEM) (n = 4) observation, and energy-dispersive X-ray spectroscopy (EDX) (n = 5) analysis. In vitro Streptococcus mutans biofilm formation on the specimens of each group was determined using confocal laser scanning microscopy and SEM analysis (n = 14). The data were analyzed using two-way analysis of variance, with Bonferroni as a post-hoc test and Pearson's correlation (p < .05). Microhybrid RC presented more surface roughness (p = .014) and cariogenic biofilm formation (p = .040). The surface roughness (F = 0.733, p = .536) and cariogenic biofilm formation (F = 1.685, p = .181) values were not affected by the beverages. However, according to qualitative SEM and EDX measurements, these parameters varied depending on the beverage groups. No correlation was found between surface roughness and cariogenic biofilm formation (r = 0.135, p = .287). Microhybrid RCs had a rougher surface and a higher amount of cariogenic biofilm formation than nanohybrid RCs after being subjected to different beverages.}, } @article {pmid34103078, year = {2021}, author = {Hazhirkamal, M and Zarei, O and Movahedi, M and Karami, P and Shokoohizadeh, L and Taheri, M}, title = {Molecular typing, biofilm production, and detection of carbapenemase genes in multidrug-resistant Acinetobacter baumannii isolated from different infection sites using ERIC-PCR in Hamadan, west of Iran.}, journal = {BMC pharmacology & toxicology}, volume = {22}, number = {1}, pages = {32}, pmid = {34103078}, issn = {2050-6511}, mesh = {Acinetobacter Infections/*microbiology ; *Acinetobacter baumannii/enzymology/genetics/isolation & purification/physiology ; Adolescent ; Adult ; Bacterial Proteins/*genetics ; Biofilms ; Child ; Drug Resistance, Multiple, Bacterial ; Female ; Genes, Bacterial ; Humans ; Iran ; Male ; Middle Aged ; Molecular Typing ; Polymerase Chain Reaction ; Young Adult ; beta-Lactamases/*genetics ; }, abstract = {BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen that can cause several kinds of nosocomial infections. Increasing antibiotic resistance as well as identifying genetic diversity and factors associated with pathogenicity and prevalence of this bacterium is important. The aim of this study was the investigation of molecular typing, biofilm production, and detection of carbapenemase genes in multidrug-resistant Acinetobacter baumannii isolated from different infection sites using ERIC-PCR in Iran.

METHODS: Forty isolates of A. baumannii were obtained from various wards of the central hospital, in the west of Iran. Phenotypic identification and genetic diversity, biofilm production assay, and detection of Carbapenemase genes carried out.

RESULTS: Tracheal samples 26 (61.9 %) are the most frequent isolates, and 95 % of isolates were identified as MDR. 32.5 % of all A. baumannii strains were capable to form a strong biofilm. It was founded that antimicrobial resistance patterns had a significant relationship with strong biofilm formation (P = 0.001). Most frequencies of the studied genes were in the order of VIM (81 %), SPM (45.2 %), and IMP (35.7 %) genes. The VIM gene was the most frequent in all isolates which were significant (P = 0.006). 14 different ERIC-types were observed including 7 common types and 7 unique or single types. F type is the largest common type consisting of nine isolates and B, D, and E types contain two isolates separately.

CONCLUSIONS: ERIC-PCR technique was used to genetically classify A. baumannii isolates as one of the most common microorganisms in nosocomial infections.}, } @article {pmid34102998, year = {2021}, author = {Huang, Q and Zhang, Z and Liu, Q and Liu, F and Liu, Y and Zhang, J and Wang, G}, title = {SpoVG is an important regulator of sporulation and affects biofilm formation by regulating Spo0A transcription in Bacillus cereus 0-9.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {172}, pmid = {34102998}, issn = {1471-2180}, mesh = {Bacillus cereus/genetics/growth & development/*metabolism ; Bacterial Proteins/genetics/*metabolism ; *Gene Expression Regulation, Bacterial ; Promoter Regions, Genetic ; Spores, Bacterial/genetics/*growth & development/metabolism ; Transcription Factors/genetics/*metabolism ; Transcription, Genetic ; }, abstract = {BACKGROUND: Bacillus cereus 0-9, a Gram-positive, endospore-forming bacterium isolated from healthy wheat roots in our previous research, is considered to be an effective biocontrol strain against several soil-borne plant diseases. SpoVG, a regulator that is broadly conserved among many Gram-positive bacteria, may help this organism coordinate environmental growth and virulence to survive. This study aimed to explore the multiple functions of SpoVG in B. cereus 0-9.

METHODS: The gene knockout strains were constructed by homologous recombination, and the sporulation process of B. cereus 0-9 and its mutants were observed by fluorescence staining method. We further determined the spore yields and biofilm formation abilities of test strains. Transcriptional fusion strains were constructed by overlapping PCR technique, and the promoter activity of the target gene was detected by measuring its fluorescence intensity. The biofilm production and colonial morphology of B. cereus 0-9 and its mutants were determined to study the functions of the target genes, and the transcription level of the target gene was determined by qRT-PCR.

RESULTS: According to observation of the sporulation process of B. cereus 0-9 in germination medium, SpoVG is crucial for regulating sporulation stage V of B. cereus 0-9, which is identical to that of Bacillus subtilis but differs from that of Bacillus anthracis. In addition, SpoVG could influence biofilm formation of B. cereus 0-9. The transcription levels of two genes closely related to biofilm-formation, sipW and calY, were downregulated in a ΔspoVG mutant. The role of SpoVG in regulating biofilm formation was further explored by deleting the genes abrB and sinR in the ΔspoVG mutant, respectively, generating the double mutant strains ΔspoVGΔabrB and ΔspoVGΔsinR. The phenotypes of these double mutants were congruent with those of the single abrB and sinR deletion strains, respectively, which showed increased biofilm formation. This indicated that spoVG was located upstream of abrB and sinR in the regulatory pathway of B. cereus biofilm formation. Further, the results of qRT-PCR and the luminescence intensity of transcriptional fusion strains indicated that spoVG gene deletion could inhibit the transcription of Spo0A.

CONCLUSIONS: SpoVG, an important regulator in the sporulation of B. cereus, is located upstream of Spo0A and participates in regulation of biofilm formation of B. cereus 0-9 through regulating the transcription level of spo0A. Sporulation and biofilm formation are crucial mechanisms by which bacteria respond to adverse conditions. SpoVG is therefore an important regulator of Spo0A and is crucial for both sporulation and biofilm formation of B. cereus 0-9. This study provides a new insight into the regulatory mechanism of environmental adaptation in bacteria and a foundation for future studies on biofilm formation of B. cereus.}, } @article {pmid34102004, year = {2021}, author = {Paosen, S and Lethongkam, S and Wunnoo, S and Lehman, N and Kalkornsurapranee, E and Septama, AW and Voravuthikunchai, SP}, title = {Prevention of nosocomial transmission and biofilm formation on novel biocompatible antimicrobial gloves impregnated with biosynthesized silver nanoparticles synthesized using Eucalyptus citriodora leaf extract.}, journal = {Biotechnology journal}, volume = {16}, number = {9}, pages = {e2100030}, doi = {10.1002/biot.202100030}, pmid = {34102004}, issn = {1860-7314}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; *Cross Infection ; *Eucalyptus ; Humans ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Silver/pharmacology ; }, abstract = {Failure in the prevention of cross-transmission from contaminated gloves has been recognized as an important factor that contributes to the spread of several healthcare-associated infections. Ex situ coating process with silver nanoparticles (AgNPs) using Eucalyptus citriodora ethanolic leaf extract as reducing and capping agents to coat glove surfaces has been developed to prevent this mode of transmission. Elemental analysis of coated gloves showed 24.8 Wt% silver densely adhere on the surface. The coated gloves fully eradicated important hospital-acquired pathogens including Gram-positive bacteria, Gram-negative bacteria, and yeasts within 1 h. The coated gloves showed significant reduction, an average of five logs when tested against all standard strains and most clinical isolates (p < 0.01). Following prolonged exposure, the coating significantly reduced the numbers of most adhered pathogenic species, compared with uncoated gloves (p < 0.0001). AgNPs-coated gloves reduced microbial adhesion of mixed-species biofilms. A series of contamination and transmission assays demonstrated no transmission of viable organisms. Biocompatibility analysis confirmed high viability of HaCaT and L929 cells at all concentrations of AgNPs tested. The coated gloves were non-toxic with direct contact with L929 cells. The highly efficacious AgNPs-coated gloves potentially provide additional protection against transmission of healthcare-associated infections.}, } @article {pmid34099300, year = {2021}, author = {Wang, X and Wang, Y and Ling, N and Shen, Y and Zhang, D and Liu, D and Ou, D and Wu, Q and Ye, Y}, title = {Effects of tolC on tolerance to bile salts and biofilm formation in Cronobacter malonaticus.}, journal = {Journal of dairy science}, volume = {104}, number = {9}, pages = {9521-9531}, doi = {10.3168/jds.2021-20128}, pmid = {34099300}, issn = {1525-3198}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Outer Membrane Proteins/genetics ; Bile Acids and Salts ; Biofilms ; *Cronobacter ; *Escherichia coli Proteins ; }, abstract = {Bile salts is one of essential components of bile secreted into the intestine to confer antibacterial protection. Cronobacter species are associated with necrotizing enterocolitis in newborns and show a strong tolerance to bile salts. However, little attempt has been made to focus on the molecular basis of the tolerance to bile salts. In this study, we investigated the roles of tolC on growth, cell morphology, motility, and biofilm formation ability in Cronobacter malonaticus under bile salt stress. The results indicated that the absence of tolC significantly affected the colony morphology and outer membrane structure in a normal situation, compared with those of the wild type strain. The deletion of tolC caused the decline in resistance to bile salt stress, inhibition of growth, and observable reduction in relative growth rate and motility. Moreover, the bacterial stress response promoted the biofilm formation ability of the mutant strain. The expression of the AcrAB-TolC system (acrA, acrB, and tolC) was effectively upregulated compared with the control sample when exposed to different bile salt concentrations. The findings provide valuable information for deeply understanding molecular mechanisms about the roles of tolC under bile salt stress and the prevention and control of C. malonaticus.}, } @article {pmid34096274, year = {2021}, author = {Dzofou Ngoumelah, D and Harnisch, F and Kretzschmar, J}, title = {Benefits of Age-Improved Resistance of Mature Electroactive Biofilm Anodes in Anaerobic Digestion.}, journal = {Environmental science & technology}, volume = {55}, number = {12}, pages = {8258-8266}, doi = {10.1021/acs.est.0c07320}, pmid = {34096274}, issn = {1520-5851}, mesh = {Anaerobiosis ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Geobacter ; }, abstract = {Anaerobic digestion (AD) and microbial electrochemical technologies (MET) can be combined in manifold ways. Recent studies show negative influences of AD effluents on the performance of pre-grown Geobacter spp.-dominated biofilm anodes. In this study, it was investigated how such biofilm anodes are affected by AD effluents. Therefore, experiments using AD effluents in different concentrations (0-100%) in combination with biofilms of different ages were performed. Furthermore, the activity of methanogens was inhibited and minimized by application of 2-bromoethanesulfonate (2-BES) and microfiltration, respectively. Biofilms pre-grown for 5 weeks show higher resistance against AD effluents compared to biofilms pre-grown for only 3 weeks. Nevertheless, adaptation of biofilms to AD effluents was not successful. Biofilm activity in terms of coulombic efficiency and maximum current density (jmax) dropped by factor 32.2 ± 3.2 and 38.9 ± 8.4, respectively. The application of 2-BES and microfiltration had positive effects on the biofilm activity. The results support the assumption that methanogens or further compounds not studied here, for example, protozoans, which may have been inhibited or removed by 2-BES application or microfiltration, have an immediate influence on the stability of Geobacter spp.-dominated biofilms and may limit their practical application in AD environments.}, } @article {pmid34095554, year = {2021}, author = {Mahajan, S and Sunsunwal, S and Gautam, V and Singh, M and Ramya, TNC}, title = {Biofilm inhibitory effect of alginate lyases on mucoid P. aeruginosa from a cystic fibrosis patient.}, journal = {Biochemistry and biophysics reports}, volume = {26}, number = {}, pages = {101028}, pmid = {34095554}, issn = {2405-5808}, abstract = {Chronic mucoid Pseudomonas aeruginosa infections are a major scourge in cystic fibrosis patients. Mucoid P. aeruginosa displays structured alginate-rich biofilms that are resistant to antibiotics. Here, we have assessed the efficacy of a panel of alginate lyases in combating mucoid P. aeruginosa biofilms in cystic fibrosis. Albeit we could not demonstrate alginate degradation by alginate lyases in sputum, we demonstrate that the endotypic alginate lyases, CaAly (from Cellulophaga algicola) and VspAlyVI (from Vibrio sp. QY101) and the exotypic alginate lyases, FspAlyFRB (from Falsirhodobacterium sp. alg1), and SA1-IV (from Sphingomonas sp. A1), indeed inhibit biofilm formation by a mucoid P. aeruginosa strain isolated from the sputum of a cystic fibrosis patient with comparative effect to that of the glycoside hydrolase PslG, a promising candidate for biofilm treatment. We believe that these enzymes should be explored for in vivo efficacy in future studies.}, } @article {pmid34093708, year = {2021}, author = {Zahedani, SS and Tahmasebi, H and Jahantigh, M}, title = {Coexistence of Virulence Factors and Efflux Pump Genes in Clinical Isolates of Pseudomonas aeruginosa: Analysis of Biofilm-Forming Strains from Iran.}, journal = {International journal of microbiology}, volume = {2021}, number = {}, pages = {5557361}, pmid = {34093708}, issn = {1687-918X}, abstract = {BACKGROUND: Biofilm formation and efflux pumps (EPs) correlation play a critical role in the pathogenicity and antibiotic resistance of Pseudomonas aeruginosa. In this study, biofilm formation and EP's collaborative role in clinical isolates of P. aeruginosa infection were investigated.

METHODS: Eighty-six (86) P. aeruginosa isolates were collected from different clinical specimens and were confirmed using different biochemical tests. The formation of biofilm was investigated by using a crystal violet assay. Also, EP genes were identified by the PCR method.

RESULTS: Based on the results, gentamicin-resistant (n = 50, 66.29%) and ciprofloxacin-resistant (n = 61, 69.66%) strains were the most frequent and colistin (n = 1, 1.12%) and ceftazidime (n = 12, 7.86%) resistant strains were the least prevalent. Furthermore, 22 isolates (31.42%) were MDR, and 11 isolates (12.35%) were XDR strains. Also, 19 isolates (22.47%) were classified as strong biofilm, 29 isolates (21.34%) as moderate biofilm, and 3 (11.23%) isolates as weak biofilm producers. The distribution of the EP genes was as follows: mexA (n = 44, 34.83%), mexB (n = 33, 32.58%), oprM (n = 59, 29.21%), oprD (n = 61, 30.33%), tetA (n = 22, 25.58%), tetR (n = 19, 22.09%), and emrE (n = 21, 24.41%). However, there was a strong significant association between biofilm formation and EPs in P. aeruginosa. Conclusions. In this study, we suggested that the presence of a multidrug resistance efflux pump, MexEF-OprN, significantly reduced P. aeruginosa pathogenicity. In contrast, the presence of the MexAB-OprM and MexCD-OprJ pumps did not affect virulence.}, } @article {pmid34092714, year = {2021}, author = {Ohn, HM and Mizuno, T and Miyoshi, SI}, title = {Inhibitory Effects of Escherichia coli on the Formation and Development of Staphylococcus epidermidis Biofilm.}, journal = {Biocontrol science}, volume = {26}, number = {2}, pages = {113-118}, doi = {10.4265/bio.26.113}, pmid = {34092714}, issn = {1884-0205}, mesh = {Biofilms ; *Escherichia coli ; *Staphylococcus epidermidis ; }, abstract = {In the present study, we examined whether a commensal gut bacterium Escherichia coli might prevent the formation and development of the biofilm of Staphylococcus epidermidis, a nosocomial extraintestinal pathogen but not a gut microorganism. When co-cultured with S. epidermidis, E. coli strain ATCC 35218, a non-pathogenic strain, was found to be dominant in the biofilm formed on the surface of wells of a microtiter plate. In addition, E. coli significantly incorporated and grew in a niche preoccupied by S. epidermidis biofilm. Two other E. coli strains (strain K-12 and B) also showed to interfere the biofilm formation by S. epidermidis. In contrast, S. epidermidis could not grow in a niche preoccupied by E. coli biofilm. These results suggest that, through inhibition of the formation and development of the biofilm, E. coli may eliminate S. epidermidis from the gastrointestinal tract.}, } @article {pmid34091983, year = {2021}, author = {Zhang, C and Li, Q and Zhang, L and Zhang, J}, title = {Responses of submerged macrophytes Vallisneria natans and epiphytic biofilm to floating plants Eichhornia crassipes in eutrophic water.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {10}, pages = {2237-2249}, doi = {10.1002/wer.1596}, pmid = {34091983}, issn = {1554-7531}, support = {2012ZX07103004//Major Science and Technology Program for Water Pollution Control and Treatment/ ; 2017ZX07603-004 [Correction added on 30 June 2021, after first online publication: Grant/award number has been corrected.]//Major Science and Technology Program for Water Pollution Control and Treatment/ ; }, mesh = {Biofilms ; *Eichhornia ; *Hydrocharitaceae ; *Microbiota ; Water ; }, abstract = {The degeneration of submerged macrophytes and the invasion of Eichhornia crassipes (E. crassipes) destroyed the balance of aquatic ecosystems environments. In this study, responses of Vallisneria natans (V. natans) and the leaf-epiphytic biofilms to E. crassipes were analyzed to provide a technical scheme for V. natans restoration and E. crassipes control in eutrophic water. The results showed that a significant improvement of water quality achieved in 1100 ind·m[-2] E. crassipes density group and TN removal rate reached 63.53%. The presence of E. crassipes changed the morphological characteristics of V. natans, which stimulated the adaptive mechanisms via promotion of shoot height and root length. Concentrations of the antioxidant enzymes, peroxidase, superoxide dismutase, and catalase in the V. natans leaves remained stable. But E. crassipes greatly increased the microbial diversity on V. natans leave biofilms. Furthermore, the greatest richness in bacterial community diversity was observed at 700, 1100, and 1200 ind·m[-2] E. crassipes densities in heatmap, which was beneficial to the stability of the water ecological environment. These results showed that the combination of V. natans with E. crassipes of 1100 ind m[-2] providing more favorable conditions for the growth and restoration of submerged macrophytes and improve the water quality. PRACTITIONER POINTS: The responses of submerged macrophytes to floating plants were studied. The optimal density of Eichhornia crassipes was 1100 ind m[-2] . The biofilm microbial community changed in response to Eichhornia crassipes.}, } @article {pmid34091972, year = {2022}, author = {Qiao, Y and Feng, L and Jia, R and Luo, Y and Yang, Q}, title = {Motility, biofilm formation and associated gene expression in Vibrio parahaemolyticus impaired by co-culture with live Ulva fasciata.}, journal = {Journal of applied microbiology}, volume = {132}, number = {1}, pages = {101-112}, doi = {10.1111/jam.15175}, pmid = {34091972}, issn = {1365-2672}, support = {51709236//National Natural Science Foundation of China/ ; }, mesh = {Biofilms ; Coculture Techniques ; Gene Expression ; *Ulva ; *Vibrio parahaemolyticus/genetics ; }, abstract = {AIMS: Vibrio parahaemolyticus is one of the most frequently occurred pathogens in mariculture. This study aimed to explore the mechanism of the impact of Ulva fasciata on the motility and biofilm formation of V. parahaemolyticus.

METHODS AND RESULTS: The inhibitory effect of U. fasciata on a V. parahaemolyticus, isolated from clam maricultural sediment, was examined by co-culture of them. The live U. fasciata significantly inhibited the swimming behaviour, twitching behaviour and biofilm formation of V. parahaemolyticus JF, with inhibition rates range of 2.48%-20.26%, 1.59%-39.18% and 28.3%-94.7% under different nitrate and phosphate levels, respectively. The results of transcriptome sequencing showed that 210 significantly differentially expressed genes (DEGs) were found in strain JF between the presence and absence of U. fasciata, including 90 upregulated genes and 120 downregulated genes. According to GO (Gene Ontology) function enrichment and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis, the downregulated genes of JF were partially enriched in flagella assembly (fliC, fliK, fliG, fliN, fliH, fliI, fliJ and fliA), bacterial chemotaxis (mCP, cheB, cheW and cheY) and biofilm formation (fliA/σ[28] and eps), which explained the suppressed motility and biofilm formation of V. parahaemolyticus JF under U. fasciata stress.

CONCLUSIONS: Live U. fasciata significantly impaired the motility and biofilm formation of V. parahaemolyticus, which could occur in niches with either sufficient or inadequate nutrient (nitrate and phosphate) concentrations. The DEGs of V. parahaemolyticus modulated by U. fasciata were enriched mainly in the flagellar assembly, bacterial chemotaxis and biofilm pathways.

New information on how V. parahaemolyticus respond to U. fasciata regarding motility and adhesion behaviours, and the mechanism of that was firstly explored in this study. The results suggested that the seaweed U. fasciata has promising prospects as an environmentally friendly preventive measure to treat vibriosis in mariculture.}, } @article {pmid34091701, year = {2021}, author = {Liu, J and Zhang, D and Lian, S and Gu, X and Hou, Q and Xia, P and Zhu, G}, title = {Mechanism of nitrite transporter NirC in motility, biofilm formation, and adhesion of avian pathogenic Escherichia coli.}, journal = {Archives of microbiology}, volume = {203}, number = {7}, pages = {4221-4231}, pmid = {34091701}, issn = {1432-072X}, support = {KYCX20_3004//Graduates Research & Practice Innovation Program of Jiangsu Province/ ; }, mesh = {Animals ; Anion Transport Proteins/genetics/*metabolism ; Bacterial Adhesion/genetics ; Biofilms ; Cell Line ; Escherichia coli/genetics/metabolism ; Escherichia coli Infections ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Mice ; Mutation ; RNA-Binding Proteins/genetics ; Repressor Proteins/genetics ; Virulence/genetics ; }, abstract = {The Escherichia coli (E. coli) nirC gene encodes a nitrite transporter, which involved in transporting toxic nitrite (NO2[-]) from the environment into the bacteria. Although the deletion of nirC gene could cause changes in motility, adhesion in the previous study, and the virulence involved in the specified mechanism for pathogenic E. coli remains to be known. In the present work, we aimed to evaluate the role of NirC in a serotype O2:K1:H7 avian pathogenic Escherichia coli (APEC) strain. For this purpose, we generated a NirC-deficient mutant of APEC XM strain and examined its biological characteristics. The nirC gene deletion mutant enhanced ability of motility, decreased in biofilm formation, and it markedly reduced ability to adhere mouse brain microvascular endothelial cell b.End3 cells. For understanding its mechanism, sequentially we detected and found the stress regulator rpoS and its downstream genes csrA were up-regulated in NirC-deficient mutant while diguanylate cyclase gene dgcT was down-regulated. By high-performance liquid chromatography (HPLC) experiment, we demonstrated the concentration of intracellular 3',5'-cyclic diguanosine monophosphate (c-di-GMP) significantly decrease in nirC gene deletion mutant. Taken data together, we may make a conclusion with a possible signal pathway clue, due to NirC mutation, environmental NO2[-] accumulation leads to nitrite stress and inactivates c-di-GMP synthesis by stimulating the stress regulator RpoS, resulting in changes of biological characteristics.}, } @article {pmid34090181, year = {2021}, author = {Liu, M and Zhu, X and Zhang, C and Zhao, Z}, title = {LuxQ-LuxU-LuxO pathway regulates biofilm formation by Vibrio parahaemolyticus.}, journal = {Microbiological research}, volume = {250}, number = {}, pages = {126791}, doi = {10.1016/j.micres.2021.126791}, pmid = {34090181}, issn = {1618-0623}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Mutagenesis, Site-Directed ; Phenotype ; Phosphoproteins/*genetics ; Phosphorylation ; Signal Transduction/*genetics/physiology ; Transcription Factors/genetics ; Vibrio parahaemolyticus/*genetics/*metabolism ; }, abstract = {Vibrio parahaemolyticus, a common foodborne pathogen, can form biofilms for survival in various environments and for bacterial transmission. Lux systems in Vibrio species are the typical two-component signal transduction systems, which have been demonstrated to contribute to various phenotypes; however, the functions of each homolog of the Lux system in V. parahaemolyticus in the regulation of biofilm formation remain largely unknown. In this study, we first showed that LuxQ, LuxU, and LuxO are essential for controlling biofilm formation by V. parahaemolyticus, through gene knockout studies. We also found that they acted in the same signaling pathway and their deletion mutants exhibited a similar level of biofilm formation. Furthermore, site-directed mutagenesis revealed that the conserved residues for phosphorylation in LuxQ (D784), LuxU (H56) and LuxO (D47) were critical for their regulatory functions on biofilm formation. Phos-tag™ sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the phosphorylation of LuxU and LuxQ in vivo. Finally, qPCR analysis displayed that the three mutants had a significant decrease in the transcription level of cps loci and cpsQ compared with the wild type strain, which is consistent with the observed phenotype of biofilm formation. Therefore, we propose that LuxQ and its downstream factors LuxU and LuxO function in the same signaling cascade to control biofilm formation by regulating the expression of cpsQ and cps loci. The results of this study provide new data regarding the role of the LuxQ-LuxU-LuxO pathway in biofilm formation by V. parahaemolyticus and help further understand the complex regulatory functions of Lux pathways.}, } @article {pmid34089933, year = {2021}, author = {Roy, PK and Ha, AJ and Mizan, MFR and Hossain, MI and Ashrafudoulla, M and Toushik, SH and Nahar, S and Kim, YK and Ha, SD}, title = {Effects of environmental conditions (temperature, pH, and glucose) on biofilm formation of Salmonella enterica serotype Kentucky and virulence gene expression.}, journal = {Poultry science}, volume = {100}, number = {7}, pages = {101209}, pmid = {34089933}, issn = {1525-3171}, mesh = {Animals ; Biofilms ; Chickens ; Gene Expression ; Glucose ; Hydrogen-Ion Concentration ; Kentucky ; *Salmonella enterica ; Serogroup ; Temperature ; Virulence ; }, abstract = {Salmonella is a foodborne pathogen and an emerging zoonotic bacterial threat in the food industry. The aim of this study was to evaluate the biofilm formation by a cocktail culture of 3 wild isolates of Salmonella enterica serotype Kentucky on plastic (PLA), silicon rubber (SR), and chicken skin surfaces under various temperatures (4, 10, 25, 37, and 42°C) and pH values (4.0, 5.0, 6.0, 7.0, and 8.0). Then, at the optimum temperature and pH, the effects of supplementation with glucose (0, 0.025, 0.05, and 0.4% w/v) on biofilm formation were assessed on each of the surfaces. The results indicated that higher temperatures (25 to 42°C) and pH values (7.0 and 8.0) led to more robust biofilm formation than lower temperatures (4 and 10°C) and lower pH levels (4.0 to 6.0). Moreover, biofilm formation was induced by 0.025% glucose during incubation at the optimum temperature (37°C) and pH (7.0) but inhibited by 0.4% glucose. Consistent with this finding, virulence related gene (rpoS, rpoH, hilA, and avrA) expression was increased at 0.025% glucose and significantly reduced at 0.4% glucose. This results also confirmed by field emission scanning electron microscope, confocal laser scanning microscopy, and autoinducer-2 determination. This study concluded that optimum environmental conditions (temperature 37°C, pH 7.0, and 0.25% glucose) exhibited strong biofilm formation on food and food contract surfaces as well as increased the virulence gene expression levels, indicating that these environmental conditions might be threating conditions for food safety.}, } @article {pmid34089837, year = {2021}, author = {Farrokhi, Y and Al-Shibli, B and Al-Hameedawi, DF and Neshati, Z and Makhdoumi, A}, title = {Escherichia coli enhances the virulence factors of Candida albicans, the cause of vulvovaginal candidiasis, in a dual bacterial/fungal biofilm.}, journal = {Research in microbiology}, volume = {172}, number = {4-5}, pages = {103849}, doi = {10.1016/j.resmic.2021.103849}, pmid = {34089837}, issn = {1769-7123}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/genetics/*pathogenicity ; Candidiasis, Vulvovaginal/*microbiology ; Coinfection/*microbiology ; Escherichia coli/*physiology ; Female ; Humans ; Hyphae/genetics/growth & development ; Larva/microbiology ; *Microbial Interactions ; Moths/microbiology ; *Virulence Factors ; }, abstract = {Co-infection with other microorganisms can promote the Candida albicans to be invasive. In this study, Escherichia coli and C. albicans were co-isolated from the women with candidiasis symptoms. The in vitro effects of E. coli on C. albicans hypha development, biofilm formation, antibiotic susceptibility, dispersion from the biofilm, expression of Als3, Hwp1, and Tup1 genes, and pathogenesis in Galleria mellonella were investigated. Electron microscopic images revealed that hypha induction was markedly increased in the bacteria-fungi co-culture. Biofilm formation was increased 2.2 fold in the presence of E. coli. The minimum inhibitory concentration of nystatin against Candida was increased from (μg mL[-1]) 25 to 50 in the dual biofilm. Candida dissemination was increased up to 2.7 fold from the mixed fungi/bacteria biofilm. The expression of ALS3 and HWP1 genes was increased (5.9 and 2.0 fold, respectively) while the TUP1 gene expression was decreased (0.4 fold) when C. albicans was incubated with E. coli. The simultaneous injection of C. albicans and E. coli to the insect larvae increased Galleria mortality up to 40%. This study demonstrated the effects of E. coli to promote fungi virulence factors, which suggest polymicrobial interaction should be considered during treatment of fungal infections.}, } @article {pmid34089796, year = {2021}, author = {Ding, L and Wang, J and Cai, S and Smyth, H and Cui, Z}, title = {Pulmonary biofilm-based chronic infections and inhaled treatment strategies.}, journal = {International journal of pharmaceutics}, volume = {604}, number = {}, pages = {120768}, doi = {10.1016/j.ijpharm.2021.120768}, pmid = {34089796}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Cystic Fibrosis/drug therapy ; Humans ; Lung ; *Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa ; }, abstract = {Certain pulmonary diseases, such as cystic fibrosis (CF), non-CF bronchiectasis, chronic obstructive pulmonary disease, and ventilator-associated pneumonia, are usually accompanied by respiratory tract infections due to the physiological alteration of the lung immunological defenses. Recurrent infections may lead to chronic infection through the formation of biofilms. Chronic biofilm-based infections are challenging to treat using antimicrobial agents. Therefore, effective ways to eradicate biofilms and thus relieve respiratory tract infection require the development of efficacious agents for biofilm destruction, the design of delivery carriers with biofilm-targeting and/or penetrating abilities for these agents, and the direct delivery of them into the lung. This review provides an in-depth description of biofilm-based infections caused by pulmonary diseases and focuses on current existing agents that are administered by inhalation into the lung to treat biofilm, which include i) inhalable antimicrobial agents and their combinations, ii) non-antimicrobial adjuvants such as matrix-targeting enzymes, mannitol, glutathione, cyclosporin A, and iii) liposomal formulations of anti-biofilm agents. Finally, novel agents that have shown promise against pulmonary biofilms as well as traditional and new devices for pulmonary delivery of anti-biofilm agents into the lung are also discussed.}, } @article {pmid34089493, year = {2021}, author = {Niek, WK and Teh, CSJ and Idris, N and Thong, KL and Ngoi, ST and Ponnampalavanar, SSS}, title = {Investigation of biofilm formation in methicillin-resistant Staphylococcus aureus associated with bacteraemia in a tertiary hospital.}, journal = {Folia microbiologica}, volume = {66}, number = {5}, pages = {741-749}, pmid = {34089493}, issn = {1874-9356}, support = {FP016-2014B//Ministry of Higher Education Fundamental Research Grant Scheme (FRGS)<// ; IF004-2020//International Research Funding/ ; }, mesh = {*Bacteremia/microbiology ; *Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus/physiology ; *Staphylococcal Infections/microbiology ; Tertiary Care Centers ; }, abstract = {Biofilm formation is an important physiological process in Staphylococcus aureus (S. aureus) that can cause infections in humans. In this study, the ability of 36 methicillin-resistant S. aureus (MRSA) clinical isolates to form biofilm was studied based on genotypic and phenotypic approaches. These isolates were genotyped based on the microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) and biofilm-associated genes (icaAD) via polymerase chain reactions. Phenotyping was performed based on the determination of the strength of biofilm formation of MRSA isolates in vitro. The most prevalent MSCRAMMs and biofilm-associated genes were clfA, eno, and icaD, followed by clfB. The fnbB (38.9%) and ebpS (11.1%) occurred less frequently among the MRSA isolates, while bbp and fnbA genes were absent from all isolates. The MRSA isolates were mostly moderate to strong biofilm formers, despite the heterogeneity of the MSCRAMM profiles. MRSA isolates from different infection sources (primary, catheter-related bloodstream, or secondary infections) were capable of forming strong biofilms. However, persistent bacteraemia was observed only in 19.4% of the MRSA-infected individuals. This study suggested that persistent MRSA bacteraemia in patients might not be associated with the biofilm-forming ability of the isolates.}, } @article {pmid34088301, year = {2021}, author = {Hihara, H and Tagaino, R and Washio, J and Laosuwan, K and Wicaksono, DP and Izumita, K and Koide, R and Takahashi, N and Sasaki, K}, title = {Effectiveness and safety of a new dental plaque removal device utilizing micro mist spray for removing oral biofilm in vitro.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {286}, pmid = {34088301}, issn = {1472-6831}, support = {JP 20K10027//Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research/ ; JP 20K10027//Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research/ ; JP 20K10027//Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research/ ; JP 20K10027//Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research/ ; JP 20K10027//Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research/ ; JP 19he1302008//Japan Agency for Medical Research and Development/ ; JP 19he1302008//Japan Agency for Medical Research and Development/ ; JP 19he1302008//Japan Agency for Medical Research and Development/ ; JP 19he1302008//Japan Agency for Medical Research and Development/ ; }, mesh = {Aged ; Biofilms ; *Dental Plaque/prevention & control ; Humans ; Streptococcus mutans ; Surface Properties ; }, abstract = {BACKGROUND: Removal of oral biofilm from the oral mucosa is essential for preventing risk of respiratory and gastrointestinal infection in elderly people. Currently, no device is available which can remove oral biofilm from oral mucosa effectively and safely. Therefore, the effectiveness and safety of the Micro Scale Mist UNIT (MSM-UNIT), a newly developed dental plaque removal device utilizing high speed sprays of fine water droplets, were evaluated for biofilm removal, including the rate and surface roughness for simulated tooth surface and mucous membrane.

METHODS: Simulated tooth and oral mucosa coated with an artificial biofilm of Streptococcus mutans were used for evaluation of effectiveness, with uncoated substrates as the controls. The MSM-UNIT and a conventional air ablation device were operated under recommended instructions. The effectiveness was evaluated from the rate of removal of the biofilm, and the safety was evaluated from the damage observed by scanning electron microscope and surface roughness.

RESULTS: The biofilm removal rate of the MSM-UNIT was significantly higher than that of AIRFLOW. Little damage was observed in the area treated by the MSM-UNIT. The surface roughness of the MSM-UNIT treated area on simulated tooth surface and oral mucosa showed no significant difference to the control area. In contrast, cracks and powder were observed in the area treated by AIRFLOW. In particular, the surface roughness of the AIRFLOW treated area for Toughsilon was significantly larger than that of the control.

CONCLUSIONS: The MSM-UNIT could be used safely and effectively for removing biofilm not only on simulated tooth surfaces but also simulated mucous membrane. The MSM-UNIT has no harmful effect on teeth or oral mucosa, and may be used for comprehensive oral care for patients during nursing care and the perioperative period.}, } @article {pmid34088112, year = {2021}, author = {Lu, N and Li, L and Wang, C and Wang, Z and Wang, Y and Yan, Y and Qu, J and Guan, J}, title = {Simultaneous enhancement of power generation and chlorophenol degradation in nonmodified microbial fuel cells using an electroactive biofilm carbon felt anode.}, journal = {The Science of the total environment}, volume = {783}, number = {}, pages = {147045}, doi = {10.1016/j.scitotenv.2021.147045}, pmid = {34088112}, issn = {1879-1026}, abstract = {Microbial fuel cells (MFCs) are an emerging technique presenting remarkable potential. In the current MFC, an electroactive biofilm anode was inoculated with activated sludge from a local municipal sewage treatment plant. The output voltage peaked at 0.60 V and 0.56 V in MFCs cultured with 2-chlorophenol (MFC-2-CP) and 2,4-dichlorophenol (MFC-2,4-DCP), respectively. The degradation and mineralization efficiency in MFC-2-CP were 100.0% and 82.0%, respectively. Based on the bacterial 16S rRNA gene sequence analysis, abundant Acinetobacter and Azospirillum existed during both the bioelectricity and biodegradation stages in MFC-2-CP, but different patterns were exhibited in MFC-2,4-DCP. The electrogenic bacteria relied on the electron transfer pathway of nicotinamide adenine dinucleotide dehydrogenase, succinate dehydrogenase and terminal oxidase, while the electrons were transferred to the extracellular electrode by cytochrome C, riboflavin, degradation products of CPs and flagella. 2-CP and 2,4-DCP were biodegraded into less toxic cyclohexanol via dichlorination, hydroxylation, and hydrogenation; hereafter, the ring was opened to generate long-chain hydrocarbons, and finally mineralized into CO2 and H2O. This work provided a new strategy for MFCs in power generation and contaminant treatment.}, } @article {pmid34088103, year = {2021}, author = {Yang, C and Liu, T and Chen, N and Tong, S and Deng, Y and Xue, L and Hu, W and Feng, C}, title = {Performance and mechanism of a novel woodchip embedded biofilm electrochemical reactor (WBER) for nitrate-contaminated wastewater treatment.}, journal = {Chemosphere}, volume = {276}, number = {}, pages = {130250}, doi = {10.1016/j.chemosphere.2021.130250}, pmid = {34088103}, issn = {1879-1298}, mesh = {Autotrophic Processes ; Biofilms ; Bioreactors ; *Nitrates ; *Water Purification ; }, abstract = {In this study, a woodchip biofilm electrode reactor (WBER) with woodchips embedded anode and cathode was developed, and its denitrification mechanism was analyzed by investigating the denitrification performance, organic matter change, redox environment and microbial community. The results show that the WBER with a carbon rod as anode (C-WBER) had a higher denitrification efficiency (2.58 mg NO- 3-N/(L·h)) and lower energy consumption (0.012 kWh/g NO- 3-N) at 350 mA/m[2]. By reducing the hydroxyl radical and dissolved oxygen concentrations, anode embedding technology effectively decreased the inhibition on microorganisms. Lignin decomposition, nitrification and aerobic denitrification were carried out in anode. Additionally, hydrogen autotrophic denitrification and heterotrophic denitrification were occurred in cathode. The WBER effectively removed nitrate and reduced the cost, providing a theoretical basis and direction for further develop BERs.}, } @article {pmid34087388, year = {2021}, author = {Ozma, MA and Khodadadi, E and Rezaee, MA and Kamounah, FS and Asgharzadeh, M and Ganbarov, K and Aghazadeh, M and Yousefi, M and Pirzadeh, T and Kafil, HS}, title = {Induction of proteome changes involved in biofilm formation of Enterococcus faecalis in response to gentamicin.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {105003}, doi = {10.1016/j.micpath.2021.105003}, pmid = {34087388}, issn = {1096-1208}, mesh = {Biofilms ; *Enterococcus faecalis ; Gentamicins/pharmacology ; *Gram-Positive Bacterial Infections ; Humans ; Proteome ; Proteomics ; }, abstract = {BACKGROUND: Enterococcus faecalis is a significant cause of nosocomial infections and other diseases, including endocarditis, bacteremia, and urinary tract infections. This microorganism forms biofilms to overcome difficult environmental conditions, such as lack of oxygen, lack of water, and the presence of antimicrobials. These biofilms make diseases difficult by changing their proteome contents, protecting the bacterium, and increasing their pathogenicity. This study aimed to evaluate gentamicin's effect on proteome changes and biofilm formation in E. faecalis.

METHOD: Twenty-five clinical isolates and one standard isolate were selected for the experiments. A label-free/gel-free proteomic and microtiter plate techniques were used to study proteome changes and biofilm formation, respectively.

RESULTS: Gentamicin significantly increased the biofilm formation in 62% of isolates and the rest of the isolates; no significant change was observed. The abundance of lactate utilization protein C, ribosomal RNA small subunit methyltransferase H, and protein translocase subunit SecA were increased. However, the abundances of proteins effective in cell division and metabolism, such as replication initiation protein and segregation and condensation protein A, were decreased.

CONCLUSION: The present study's findings exhibited that antibiotics might have adverse effects on treatment and increase microorganisms' pathogenicity. It was observed in gentamicin as induction of biofilm formation through different mechanisms, particularly changes in the expression of specific proteins in E. faecalis.}, } @article {pmid34085776, year = {2021}, author = {Danforth, DR and Melloni, M and Tristano, J and Mintz, KP}, title = {Contribution of adhesion proteins to Aggregatibacter actinomycetemcomitans biofilm formation.}, journal = {Molecular oral microbiology}, volume = {36}, number = {4}, pages = {243-253}, pmid = {34085776}, issn = {2041-1014}, support = {R01 DE024554/DE/NIDCR NIH HHS/United States ; S10 OD025030/OD/NIH HHS/United States ; }, mesh = {*Adhesins, Bacterial/genetics ; *Aggregatibacter actinomycetemcomitans/genetics ; Biofilms ; Fimbriae, Bacterial/genetics ; Membrane Proteins ; }, abstract = {Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium associated with periodontal disease and multiple disseminated extra-oral infections. Colonization of these distinct physiological niches is contingent on the expression of specific surface proteins during the initiation of developing biofilms. In this investigation, we studied fimbriae and three well-characterized nonfimbrial surface proteins (EmaA, Aae, and ApiA/Omp100) for their contribution to biofilm formation. Mutations of these proteins in multiple strains covering four different serotypes demonstrated variance in biofilm development that was strain dependent but independent of serotype. In a fimbriated background, only inactivation of emaA impacted biofilm mass. In contrast, inactivation of emaA and/or aae affected biofilm formation in nonfimbriated A. actinomycetemcomitans strains, whereas inactivation of apiA/omp100 had little effect on biofilm formation. When these genes were expressed individually in Escherichia coli, all transformed strains demonstrated an increase in biofilm mass compared to the parent strain. The strain expressing emaA generated the greatest mass of biofilm, whereas the strains expressing either aae or apiA/omp100 were greatly reduced and similar in mass. These data suggest a redundancy in function of these nonfimbrial adhesins, which is dependent on the genetic background of the strain investigated.}, } @article {pmid34085032, year = {2021}, author = {Merkl, P and Zhou, S and Zaganiaris, A and Shahata, M and Eleftheraki, A and Thersleff, T and Sotiriou, GA}, title = {Plasmonic Coupling in Silver Nanoparticle Aggregates and Their Polymer Composite Films for Near-Infrared Photothermal Biofilm Eradication.}, journal = {ACS applied nano materials}, volume = {4}, number = {5}, pages = {5330-5339}, pmid = {34085032}, issn = {2574-0970}, support = {758705/ERC_/European Research Council/International ; }, abstract = {Plasmonic nanoparticles with near-IR (NIR) light absorption are highly attractive in biomedicine for minimally invasive photothermal treatments. However, these optical properties are typically exhibited by plasmonic nanostructures with complex, nonspherical geometries that may prohibit their broad commercialization and further integration into photothermal devices. Herein, we present the single-step aerosol self-assembly of plasmonic nanoaggregates that consisted of spherical silver nanoparticles with tunable extinction from visible to NIR wavelengths. This tunable extinction was achieved by the addition of SiO2 during the flame synthesis of the nanoparticles, which acted as a dielectric spacer between the spherical silver nanoparticles and was also computationally validated by simulating the extinction spectra of similar silver nanoaggregates. These plasmonic nanoaggregates were easily deposited on silicone polymeric surfaces and further encased with a top polymer layer, forming plasmonic photothermal nanocomposite films. The photothermal properties of the NIR nanocomposite films were utilized to eradicate the established biofilms of clinically relevant Escherichia coli and Staphylococcus aureus, with a relationship observed between the final surface temperature and biofilm eradication.}, } @article {pmid34084700, year = {2021}, author = {Brooks, JR and Dusane, DH and Moore, K and Gupta, T and Delury, C and Aiken, SS and Laycock, PA and Sullivan, AC and Granger, JF and Dipane, MV and McPherson, EJ and Stoodley, P}, title = {Pseudomonas aeruginosa biofilm killing beyond the spacer by antibiotic-loaded calcium sulfate beads: an in vitro study.}, journal = {Journal of bone and joint infection}, volume = {6}, number = {5}, pages = {119-129}, pmid = {34084700}, issn = {2206-3552}, abstract = {Introduction: Bacterial biofilms are an important virulence factor in chronic periprosthetic joint infection (PJI) and other orthopedic infection since they are highly tolerant to antibiotics and host immunity. Antibiotics are mixed into carriers such as bone cement and calcium sulfate bone void fillers to achieve sustained high concentrations of antibiotics required to more effectively manage biofilm infections through local release. The effect of antibiotic diffusion from antibiotic-loaded calcium sulfate beads (ALCS-B) in combination with PMMA bone cement spacers on the spread and killing of Pseudomonas aeruginosa Xen41 (PA-Xen41) biofilm was investigated using a "large agar plate" model scaled for clinical relevance. Methods: Bioluminescent PA-Xen41 biofilms grown on discs of various orthopedic materials were placed within a large agar plate containing a PMMA full-size mock "spacer" unloaded or loaded with vancomycin and tobramycin, with or without ALCS-B. The amount of biofilm spread and log reduction on discs at varying distances from the spacer was assessed by bioluminescent imaging and viable cell counts. Results: For the unloaded spacer control, PA-Xen41 spread from the biofilm to cover the entire plate. The loaded spacer generated a 3 cm zone of inhibition and significantly reduced biofilm bacteria on the discs immediately adjacent to the spacer but low or zero reductions on those further away. The combination of ALCS-B and a loaded PMMA spacer greatly reduced bacterial spread and resulted in significantly greater biofilm reductions on discs at all distances from the spacer. Discussion: The addition of ALCS-B to an antibiotic-loaded spacer mimic increased the area of antibiotic coverage and efficacy against biofilm, suggesting that a combination of these depots may provide greater physical antibiotic coverage and more effective dead space management, particularly in zones where the spread of antibiotic is limited by diffusion (zones with little or no fluid motion).}, } @article {pmid34082787, year = {2021}, author = {Edel, M and Sturm, G and Sturm-Richter, K and Wagner, M and Ducassou, JN and Couté, Y and Horn, H and Gescher, J}, title = {Extracellular riboflavin induces anaerobic biofilm formation in Shewanella oneidensis.}, journal = {Biotechnology for biofuels}, volume = {14}, number = {1}, pages = {130}, pmid = {34082787}, issn = {1754-6834}, support = {ANR-10-INBS-08-01//Agence Nationale de la Recherche/ ; 031B0847A//Bundesministerium für Bildung und Forschung/ ; }, abstract = {BACKGROUND: Some microorganisms can respire with extracellular electron acceptors using an extended electron transport chain to the cell surface. This process can be applied in bioelectrochemical systems in which the organisms produce an electrical current by respiring with an anode as electron acceptor. These organisms apply flavin molecules as cofactors to facilitate one-electron transfer catalyzed by the terminal reductases and in some cases as endogenous electron shuttles.

RESULTS: In the model organism Shewanella oneidensis, riboflavin production and excretion trigger a specific biofilm formation response that is initiated at a specific threshold concentration, similar to canonical quorum-sensing molecules. Riboflavin-mediated messaging is based on the overexpression of the gene encoding the putrescine decarboxylase speC which leads to posttranscriptional overproduction of proteins involved in biofilm formation. Using a model of growth-dependent riboflavin production under batch and biofilm growth conditions, the number of cells necessary to produce the threshold concentration per time was deduced. Furthermore, our results indicate that specific retention of riboflavin in the biofilm matrix leads to localized concentrations, which by far exceed the necessary threshold value.

CONCLUSION: This study describes a new quorum-sensing mechanism in S. oneidensis. Biofilm formation of S. oneidensis is induced by low concentrations of riboflavin resulting in an upregulation of the ornithine-decarboxylase speC. The results can be applied for the development of strains catalyzing increased current densities in bioelectrochemical systems.}, } @article {pmid34080042, year = {2021}, author = {Mainetti, T and Palmisano, M and Rezzonico, F and Stres, B and Kern, S and Smits, THM}, title = {Broad diversity of bacteria degrading 17ß-estradiol-3-sulfate isolated from river sediment and biofilm at a wastewater treatment plant discharge.}, journal = {Archives of microbiology}, volume = {203}, number = {7}, pages = {4209-4219}, pmid = {34080042}, issn = {1432-072X}, mesh = {*Bacteria/classification/genetics ; *Biodiversity ; *Biofilms ; Estradiol/*analogs & derivatives/analysis/metabolism ; *Geologic Sediments/microbiology ; Water Pollutants, Chemical/analysis/metabolism ; Water Purification ; }, abstract = {Conjugated estrogens, such as 17β-estradiol-3-sulfate (E2-3S), can be released into aquatic environments through wastewater treatment plants (WWTP). There, they are microbiologically degraded into free estrogens, which can have harmful effects on aquatic wildlife. Here, the degradation of E2-3S in environmental samples taken upstream, downstream and at the effluent of a WWTP was assessed. Sediment and biofilm samples were enriched for E2-3S-degrading microorganisms, yielding a broad diversity of bacterial isolates, including known and novel degraders of estrogens. Since E2-3S-degrading bacteria were also isolated in the sample upstream of the WWTP, the WWTP does not influence the ability of the microbial community to degrade E2-3S.}, } @article {pmid34078547, year = {2023}, author = {AlMojel, N and AbdulAzees, PA and Lamb, EM and Amaechi, BT}, title = {Determining growth inhibition of Candida albicans biofilm on denture materials after application of an organoselenium-containing dental sealant.}, journal = {The Journal of prosthetic dentistry}, volume = {129}, number = {1}, pages = {205-212}, doi = {10.1016/j.prosdent.2021.04.015}, pmid = {34078547}, issn = {1097-6841}, mesh = {Humans ; Candida albicans ; Pit and Fissure Sealants/pharmacology ; *Stomatitis, Denture/prevention & control ; *Selenium/pharmacology ; Acrylic Resins/pharmacology/therapeutic use ; Biofilms ; Dentures ; Denture Bases ; Surface Properties ; }, abstract = {STATEMENT OF PROBLEM: Denture stomatitis is a chronic inflammatory condition caused by the formation of Candida albicans biofilm on denture bases. It is associated with aggravating intraoral pain, itching, and burning sensations. It can also potentiate cardiovascular diseases and aspiration pneumonia. The problem has thus far eluded efficient, toxic-free, and cost-effective solutions.

PURPOSE: The purpose of this in vitro study was to investigate the effectiveness of organoselenium to inhibit the formation of C. albicans biofilm on the surface of acrylic resin denture base materials when it is either incorporated into the acrylic resin material or coated on the denture surface as a light-polymerized surface sealant.

MATERIAL AND METHODS: Sixty heat-polymerized polymethyl methacrylate disks were fabricated and assigned to 4 groups (n=15): disks coated with a light-polymerized organoselenium-containing enamel surface sealant (DenteShield), disks impregnated with 0.5% organoselenium (0.5% selenium), disks impregnated with 1% organoselenium (1% selenium), and disks without organoselenium (control). C. albicans biofilm was grown on each disk which had been placed in a well of the microtiter plate containing 1-mL brain heart infusion broth inoculated with C. albicans. The plates were incubated aerobically at 37 °C for 48 hours. A confocal laser scanning microscope was used to determine the biofilm thickness, biomass, and live/dead cell ratio. Biofilm morphology was examined with scanning electron microscopy, whereas microbial viability was quantified by the spread plate method. The data were analyzed by using ANOVA and Tukey-Kramer multiple comparisons (α=.05).

RESULTS: The microbial viability, biofilm thickness, biofilm biomass, and live/dead cell ratio were lower (P<.001) on disks in the test groups (DenteShield, 0.5% selenium, 1% selenium) when compared with the control group, with these variables being lowest in the 0.5% selenium and 1% selenium groups. The 0.5% selenium and 1% selenium groups did not differ significantly from each other in any of the variables (P>.05). Scanning electron microscope images showed inhibition of both biofilm growth and yeast to hyphae transition in the DenteShield, 0.5% selenium, and 1% selenium groups, with visible disruption of the biofilm morphology.

CONCLUSIONS: The present study demonstrated that organoselenium, whether incorporated into or coated on the surface of an acrylic resin denture base material, has the potential to inhibit Candida albicans biofilm growth on denture surfaces and as such can be clinically useful for the prevention of denture stomatitis.}, } @article {pmid34077580, year = {2021}, author = {Lahiri, D and Nag, M and Dutta, B and Dey, S and Mukherjee, D and Joshi, SJ and Ray, RR}, title = {Antibiofilm and anti-quorum sensing activities of eugenol and linalool from Ocimum tenuiflorum against Pseudomonas aeruginosa biofilm.}, journal = {Journal of applied microbiology}, volume = {131}, number = {6}, pages = {2821-2837}, doi = {10.1111/jam.15171}, pmid = {34077580}, issn = {1365-2672}, mesh = {Acyclic Monoterpenes ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Eugenol/pharmacology ; Extracellular Polymeric Substance Matrix ; Ocimum sanctum ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors ; }, abstract = {AIMS: The aim of this study is to determine the ability of two bioactive compounds, namely, eugenol and linalool, purified from leaves of Ocimum tenuiflorum for eradication of biofilm produced by Pseudomonas aeruginosa.

METHODS AND RESULTS: The phytoextract of O. tenuiflorum (KT), a common ethno-botanical plant of India, was purified through high-performance liquid chromatography and was analysed using ultraviolet (UV) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Eugenol and linalool were found to be the most active amongst all phytocompounds present in phytoextract and showed a significant reduction in the viability of sessile cells of P. aeruginosa and the minimum revival after withdrawal of phyto-challenge. They could bring about notable reduction in the protein and carbohydrate content of exopolysaccharide of biofilm. Eugenol and linalool could affect the synthesis of quorum sensing (QS) proteins like LasA and LasB as well as virulence factors such as pyocyanin, and rhamnolipids, which seriously hamper the formation of biofilm. The biofilm framework was extremely affected by the phytocompounds through the reduction of protein and carbohydrate content of extracellular polymeric substance (EPS). Another interesting found out was that they brought about maximum inhibition to the genomic DNA and RNA content. The studies were supported by in silico interaction between eugenol and linalool with the QS proteins. The antibiofilm efficacies of eugenol, linalool and phytoextract (KT) were further confirmed by microscopic studies with scanning electron microscopy (SEM), atomic force microscopy and fluorescence confocal microscopy microscopic studies.

CONCLUSIONS: The phytocompounds are proved to be more effective than conventional antibiotics in inhibiting the biofilm forming sessile cells and can be used as a replacement for antibiotic.

Pure eugenol extracted from common basil leaves can be used as a safe substitute for common antibiotic for treatment of chronic infections caused by P. aeruginosa. It will be cost effective, devoid of notable side effects and will not generate antibiotic resistance in host body.}, } @article {pmid34077284, year = {2021}, author = {He, YZ and Xu, Y and Sun, J and Gao, BL and Li, G and Zhou, YF and Lian, XL and Fang, LX and Liao, XP and Mediavilla, JR and Chen, L and Liu, YH}, title = {Novel Plasmid-Borne Fimbriae-Associated Gene Cluster Participates in Biofilm Formation in Escherichia coli.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {12}, pages = {1624-1632}, doi = {10.1089/mdr.2020.0512}, pmid = {34077284}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects/*genetics ; Fimbriae, Bacterial/drug effects/*genetics ; Genes, Bacterial ; Microbial Sensitivity Tests ; Phenotype ; Plasmids/drug effects/*genetics ; }, abstract = {This study reported the involvement of a gene cluster from a conjugative plasmid in the biofilm formation of Escherichia coli. We used a novel EZ-Tn5 transposon technique to generate a transposon library and used arbitrarily primed PCR to detect the insertion sites in biofilm formation-deficient mutants. To validate the function of candidate biofilm formation genes, the genes were cloned into plasmid pBluescript II SK (+) and transformed into E. coil DH5α. Biofilm production from the transformants was then assessed by phenotypic biofilm formation using Crystal Violet staining and microscopy. A total of 3,000 transposon mutants of E. coli DH5α-p253 were screened, of which 28 were found to be deficient in biofilm formation. Further characterization revealed that 24/28 mutations were detected with their insertions in chromosome, while the remaining 4 mutations were evidenced that the functional genes for biofilm formation were harbored in the plasmid. Interestingly, the plasmid sequencing showed that these four transposon mutations were all inserted into a fimbriae-associated gene cluster (fim-cluster). This fim-cluster is a hybrid segment spanning a 7,949 bp sequence, with a terminal inverted repeat sequence and two coding regions. In summary, we performed a high-efficiency screening to a library constructed with the EZ-Tn5-based transposon approach and identified the gene clusters responsible for the biofilm production of E. coli, especially the genes harbored in the plasmid. Further studies are needed to understand the spread of this novel plasmid-mediated biofilm formation gene in clinical E. coli isolates and the clinical impacts.}, } @article {pmid34076405, year = {2021}, author = {Noble, K and Lu, J and Guevara, MA and Doster, RS and Chambers, SA and Rogers, LM and Moore, RE and Spicer, SK and Eastman, AJ and Francis, JD and Manning, SD and Rajagopal, L and Aronoff, DM and Townsend, SD and Gaddy, JA}, title = {Group B Streptococcus cpsE Is Required for Serotype V Capsule Production and Aids in Biofilm Formation and Ascending Infection of the Reproductive Tract during Pregnancy.}, journal = {ACS infectious diseases}, volume = {7}, number = {9}, pages = {2686-2696}, pmid = {34076405}, issn = {2373-8227}, support = {UL1 TR000445/TR/NCATS NIH HHS/United States ; R01 HD090061/HD/NICHD NIH HHS/United States ; P30 DK058404/DK/NIDDK NIH HHS/United States ; T32 AI112541/AI/NIAID NIH HHS/United States ; R01 AI134036/AI/NIAID NIH HHS/United States ; P30 EY008126/EY/NEI NIH HHS/United States ; S10 RR027396/RR/NCRR NIH HHS/United States ; F32 HD100087/HD/NICHD NIH HHS/United States ; P30 CA068485/CA/NCI NIH HHS/United States ; UL1 RR024975/RR/NCRR NIH HHS/United States ; K08 AI151100/AI/NIAID NIH HHS/United States ; U01 TR002398/TR/NCATS NIH HHS/United States ; R35 GM133602/GM/NIGMS NIH HHS/United States ; U24 DK059637/DK/NIDDK NIH HHS/United States ; S10 RR026373/RR/NCRR NIH HHS/United States ; K12 HD000850/HD/NICHD NIH HHS/United States ; T32 HL007411/HL/NHLBI NIH HHS/United States ; I01 BX005352/BX/BLRD VA/United States ; P30 DK020593/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; *Bacterial Capsules ; Biofilms ; Female ; Mice ; *Placenta ; Pregnancy ; Serogroup ; Streptococcus agalactiae/genetics ; }, abstract = {Group B Streptococcus (GBS) is an encapsulated Gram-positive pathogen that causes ascending infections of the reproductive tract during pregnancy. The capsule of this organism is a critical virulence factor that has been implicated in a variety of cellular processes to promote pathogenesis. Primarily comprised of carbohydrates, the GBS capsule and its synthesis is driven by the capsule polysaccharide synthesis (cps) operon. The cpsE gene within this operon encodes a putative glycosyltransferase that is responsible for the transfer of a Glc-1-P from UDP-Glc to an undecaprenyl lipid molecule. We hypothesized that the cpsE gene product is important for GBS virulence and ascending infection during pregnancy. Our work demonstrates that a GBS cpsE mutant secretes fewer carbohydrates, has a reduced capsule, and forms less biofilm than the wild-type parental strain. We show that, compared to the parental strain, the ΔcpsE deletion mutant is more readily taken up by human placental macrophages and has a significantly attenuated ability to invade and proliferate in the mouse reproductive tract. Taken together, these results demonstrate that the cpsE gene product is an important virulence factor that aids in GBS colonization and invasion of the gravid reproductive tract.}, } @article {pmid34076337, year = {2021}, author = {Singh, R and Ren, Z and Shi, Y and Lin, S and Kwon, KC and Balamurugan, S and Rai, V and Mante, F and Koo, H and Daniell, H}, title = {Affordable oral health care: dental biofilm disruption using chloroplast made enzymes with chewing gum delivery.}, journal = {Plant biotechnology journal}, volume = {19}, number = {10}, pages = {2113-2125}, pmid = {34076337}, issn = {1467-7652}, support = {R01 HL 109442/GF/NIH HHS/United States ; R01 HL 107904/GF/NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R01DE018023/GF/NIH HHS/United States ; R01 HL133191/HL/NHLBI NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; DE025220/GF/NIH HHS/United States ; R01 HL 133191/GF/NIH HHS/United States ; R01 HL107904/HL/NHLBI NIH HHS/United States ; R01 HL109442/HL/NHLBI NIH HHS/United States ; R01 GM063879/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; *COVID-19 ; *Chewing Gum ; Chloroplasts ; Delivery of Health Care ; Humans ; SARS-CoV-2 ; }, abstract = {Current approaches for oral health care rely on procedures that are unaffordable to impoverished populations, whereas aerosolized droplets in the dental clinic and poor oral hygiene may contribute to spread of several infectious diseases including COVID-19, requiring new solutions for dental biofilm/plaque treatment at home. Plant cells have been used to produce monoclonal antibodies or antimicrobial peptides for topical applications to decrease colonization of pathogenic microbes on dental surface. Therefore, we investigated an affordable method for dental biofilm disruption by expressing lipase, dextranase or mutanase in plant cells via the chloroplast genome. Antibiotic resistance gene used to engineer foreign genes into the chloroplast genome were subsequently removed using direct repeats flanking the aadA gene and enzymes were successfully expressed in marker-free lettuce transplastomic lines. Equivalent enzyme units of plant-derived lipase performed better than purified commercial enzymes against biofilms, specifically targeting fungal hyphae formation. Combination of lipase with dextranase and mutanase suppressed biofilm development by degrading the biofilm matrix, with concomitant reduction of bacterial and fungal accumulation. In chewing gum tablets formulated with freeze-dried plant cells, expressed protein was stable up to 3 years at ambient temperature and was efficiently released in a time-dependent manner using a mechanical chewing simulator device. Development of edible plant cells expressing enzymes eliminates the need for purification and cold-chain transportation, providing a potential translatable therapeutic approach. Biofilm disruption through plant enzymes and chewing gum-based delivery offers an effective and affordable dental biofilm control at home particularly for populations with minimal oral care access.}, } @article {pmid34074404, year = {2021}, author = {Liu, L and Huang, L and Yu, D and Zhang, G and Dong, S}, title = {FeS2 nanoparticles decorated carbonized Luffa cylindrica as biofilm substrates for fabricating high performance biosensors.}, journal = {Talanta}, volume = {232}, number = {}, pages = {122416}, doi = {10.1016/j.talanta.2021.122416}, pmid = {34074404}, issn = {1873-3573}, mesh = {Biofilms ; *Biosensing Techniques ; Glucose ; *Luffa ; *Nanoparticles ; }, abstract = {A high-performance microbial biosensor was fabricated with a reasonably designed biofilm substrate, where the aerogel of carbonized Luffa cylindrica (LC) was used as the scaffold for loading biofilm and FeS2 nanoparticles (FeS2NPs) were employed to modify this aerogel (FeS2NPs/GelLC). The fabricated FeS2NPs/GelLC exhibited a spring-like structure similar with that of the raw LC, which facilitated the linkage of the scaffold and promoted its mechanical strength, and further prolonged the service period of the as-prepared biosensor from few days to two months. Meanwhile, the introduced FeS2NPs improved the microbial electron transfer of the biofilm and causing an increase in the sensor's signals from 155.0 ± 2.6 to 352.0 ± 17.1 nA and a decrease in the detection limit from 0.95 to 0.38 mg O L[-1] (S/N = 3) for the detection of glucose-glutamic acid (GGA). More important, the FeS2NPs had been demonstrated to have the capability for modulating a persistent shift of the microbial community with organic pollutant biodegradability. Compared with the GelLC, the FeS2NPs/GelLC exhibited a promising performance for measuring the synthetic sewage and real water samples in BOD assay and an increasing inhibition-ratio for detecting 3,5-dichlorophenol (DCP) in toxicity assay. Based on the vast resource and renewability of LC, this work pave a new avenue for developing high-performance microbial biosensors that are expected to be the engineering production.}, } @article {pmid34073192, year = {2021}, author = {Spiess, S and Kucera, J and Seelajaroen, H and Sasiain, A and Thallner, S and Kremser, K and Novak, D and Guebitz, GM and Haberbauer, M}, title = {Impact of Carbon Felt Electrode Pretreatment on Anodic Biofilm Composition in Microbial Electrolysis Cells.}, journal = {Biosensors}, volume = {11}, number = {6}, pages = {}, pmid = {34073192}, issn = {2079-6374}, support = {ATCZ183, IRAS//European fund for regional development, program Interreg V-A Austria - Czech Republic/ ; 861392, MELOS//Austrian Climate and Energy Fund/ ; }, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Carbon ; *Carbon Fiber ; *Electrodes ; Electrolysis ; Geobacter ; }, abstract = {Sustainable technologies for energy production and storage are currently in great demand. Bioelectrochemical systems (BESs) offer promising solutions for both. Several attempts have been made to improve carbon felt electrode characteristics with various pretreatments in order to enhance performance. This study was motivated by gaps in current knowledge of the impact of pretreatments on the enrichment and microbial composition of bioelectrochemical systems. Therefore, electrodes were treated with poly(neutral red), chitosan, or isopropanol in a first step and then fixed in microbial electrolysis cells (MECs). Four MECs consisting of organic substance-degrading bioanodes and methane-producing biocathodes were set up and operated in batch mode by controlling the bioanode at 400 mV vs. Ag/AgCl (3M NaCl). After 1 month of operation, Enterococcus species were dominant microorganisms attached to all bioanodes and independent of electrode pretreatment. However, electrode pretreatments led to a decrease in microbial diversity and the enrichment of specific electroactive genera, according to the type of modification used. The MEC containing isopropanol-treated electrodes achieved the highest performance due to presence of both Enterococcus and Geobacter. The obtained results might help to select suitable electrode pretreatments and support growth conditions for desired electroactive microorganisms, whereby performance of BESs and related applications, such as BES-based biosensors, could be enhanced.}, } @article {pmid34072656, year = {2021}, author = {Pinel, I and Biškauskaitė, R and Pal'ová, E and Vrouwenvelder, H and van Loosdrecht, M}, title = {Assessment of the Impact of Temperature on Biofilm Composition with a Laboratory Heat Exchanger Module.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34072656}, issn = {2076-2607}, abstract = {Temperature change over the length of heat exchangers might be an important factor affecting biofouling. This research aimed at assessing the impact of temperature on biofilm accumulation and composition with respect to bacterial community and extracellular polymeric substances. Two identical laboratory-scale plate heat exchanger modules were developed and tested. Tap water supplemented with nutrients was fed to the two modules to enhance biofilm formation. One "reference" module was kept at 20.0 ± 1.4 °C and one "heated" module was operated with a counter-flow hot water stream resulting in a bulk water gradient from 20 to 27 °C. Biofilms were grown during 40 days, sampled, and characterized using 16S rRNA gene amplicon sequencing, EPS extraction, FTIR, protein and polysaccharide quantifications. The experiments were performed in consecutive triplicate. Monitoring of heat transfer resistance in the heated module displayed a replicable biofilm growth profile. The module was shown suitable to study the impact of temperature on biofouling formation. Biofilm analyses revealed: (i) comparable amounts of biofilms and EPS yield in the reference and heated modules, (ii) a significantly different protein to polysaccharide ratio in the EPS of the reference (5.4 ± 1.0%) and heated modules (7.8 ± 2.1%), caused by a relatively lower extracellular sugar production at elevated temperatures, and (iii) a strong shift in bacterial community composition with increasing temperature. The outcomes of the study, therefore, suggest that heat induces a change in biofilm bacterial community members and EPS composition, which should be taken into consideration when investigating heat exchanger biofouling and cleaning strategies. Research potential and optimization of the heat exchanger modules are discussed.}, } @article {pmid34072497, year = {2021}, author = {Gomes, IB and Lemos, M and Fernandes, S and Borges, A and Simões, LC and Simões, M}, title = {The Effects of Chemical and Mechanical Stresses on Bacillus cereus and Pseudomonas fluorescens Single- and Dual-Species Biofilm Removal.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34072497}, issn = {2076-2607}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; POCI-01-0247-FEDER-072237//Agência Nacional de Inovação/ ; POCI-01-0247-FEDER-033298//Agência Nacional de Inovação/ ; }, abstract = {Biofilm control is mainly based on chemical disinfection, without a clear understanding of the role of the biocides and process conditions on biofilm removal. This study aims to understand the effects of a biocide (benzyldimethyldodecyl ammonium chloride-BDMDAC) and mechanical treatment (an increase of shear stress -τw) on single- and dual-species biofilms formed by Bacillus cereus and Pseudomonas fluorescens on high-density polyethene (HDPE). BDMDAC effects were initially assessed on bacterial physicochemical properties and initial adhesion ability. Then, mature biofilms were formed on a rotating cylinder reactor (RCR) for 7 days to assess the effects of chemical and mechanical treatments, and the combination of both on biofilm removal. The results demonstrated that the initial adhesion does not predict the formation of mature biofilms. It was observed that the dual-species biofilms were the most susceptible to BDMDAC exposure. The exposure to increasing τw emphasised the mechanical stability of biofilms, as lower values of τw&nbsp;(1.66 Pa) caused high biofilm erosion and higher τw values (17.7 Pa) seem to compress the remaining biofilm. In general, the combination of BDMDAC and the mechanical treatment was synergic in increasing biofilm removal. However, these were insufficient to cause total biofilm removal (100%; an average standard deviation of 11% for the method accuracy should be considered) from HDPE.}, } @article {pmid34072418, year = {2021}, author = {Czajkowska, J and Junka, A and Hoppe, J and Toporkiewicz, M and Pawlak, A and Migdał, P and Oleksy-Wawrzyniak, M and Fijałkowski, K and Śmiglak, M and Markowska-Szczupak, A}, title = {The Co-Culture of Staphylococcal Biofilm and Fibroblast Cell Line: The Correlation of Biological Phenomena with Metabolic NMR[1] Footprint.}, journal = {International journal of molecular sciences}, volume = {22}, number = {11}, pages = {}, pmid = {34072418}, issn = {1422-0067}, support = {2017/27/B/NZ6/02103//This research was funded by National Science Center./ ; }, mesh = {Biofilms/*growth & development ; Cell Survival ; *Coculture Techniques ; Fibroblasts/*metabolism/*microbiology/ultrastructure ; Fluorescent Antibody Technique ; Host-Pathogen Interactions ; Kinetics ; Magnetic Resonance Spectroscopy ; Metabolome ; Metabolomics/methods ; Staphylococcus aureus/*growth & development/*metabolism/ultrastructure ; }, abstract = {Staphylococcus aureus is one of the most prevalent pathogens associated with several types of biofilm-based infections, including infections of chronic wounds. Mature staphylococcal biofilm is extremely hard to eradicate from a wound and displays a high tendency to induce recurring infections. Therefore, in the present study, we aimed to investigate in vitro the interaction between S. aureus biofilm and fibroblast cells searching for metabolites that could be considered as potential biomarkers of critical colonization and infection. Utilizing advanced microscopy and microbiological methods to examine biofilm formation and the staphylococcal infection process, we were able to distinguish 4 phases of biofilm development. The analysis of staphylococcal biofilm influence on the viability of fibroblasts allowed us to pinpoint the moment of critical colonization-12 h post contamination. Based on the obtained model we performed a metabolomics analysis by [1]H NMR spectroscopy to provide new insights into the pathophysiology of infection. We identified a set of metabolites related to the switch to anaerobic metabolism that was characteristic for staphylococcal biofilm co-cultured with fibroblast cells. The data presented in this study may be thus considered a noteworthy but preliminary step in the direction of developing a new, NMR-based tool for rapid diagnosing of infection in a chronic wound.}, } @article {pmid34072318, year = {2021}, author = {Ridyard, KE and Overhage, J}, title = {The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {34072318}, issn = {2079-6382}, abstract = {The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.}, } @article {pmid34070557, year = {2021}, author = {Andrade, NC and Laranjo, M and Costa, MM and Queiroga, MC}, title = {Virulence Factors in Staphylococcus Associated with Small Ruminant Mastitis: Biofilm Production and Antimicrobial Resistance Genes.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {34070557}, issn = {2079-6382}, support = {Project UIDB/05183/2020//Fundação para a Ciência e a Tecnologia/ ; PhD grant (249398/2013-3 - GDE)//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {Small ruminant mastitis is a serious problem, mainly caused by Staphylococcus spp. Different virulence factors affect mastitis pathogenesis. The aim of this study was to investigate virulence factors genes for biofilm production and antimicrobial resistance to β-lactams and tetracyclines in 137 staphylococcal isolates from goats (86) and sheep (51). The presence of coa, nuc, bap, icaA, icaD, blaZ, mecA, mecC, tetK, and tetM genes was investigated. The nuc gene was detected in all S. aureus isolates and in some coagulase-negative staphylococci (CNS). None of the S. aureus isolates carried the bap gene, while 8 out of 18 CNS harbored this gene. The icaA gene was detected in S. aureus and S. warneri, while icaD only in S. aureus. None of the isolates carrying the bap gene harbored the ica genes. None of the biofilm-associated genes were detected in 14 isolates (six S. aureus and eight CNS). An association was found between Staphylococcus species and resistance to some antibiotics and between antimicrobial resistance and animal species. Nine penicillin-susceptible isolates exhibited the blaZ gene, questioning the reliability of susceptibility testing. Most S. aureus isolates were susceptible to tetracycline, and no cefazolin or gentamycin resistance was detected. These should replace other currently used antimicrobials.}, } @article {pmid34069837, year = {2021}, author = {Paulitsch-Fuchs, AH and Wolrab, L and Eck, N and Dyer, NP and Bödendorfer, B and Lohberger, B}, title = {TiAl6V4 Alloy Surface Modifications and Their Impact on Biofilm Development of S. aureus and S. epidermidis.}, journal = {Journal of functional biomaterials}, volume = {12}, number = {2}, pages = {}, pmid = {34069837}, issn = {2079-4983}, support = {861608//Österreichische Forschungsförderungsgesellschaft/ ; }, abstract = {One of the most serious complications following joint replacement surgeries are periprosthetic infections (PIs) arising from the adhesion of bacteria to the artificial joint. Various types of titanium-aluminum-vanadium (TiAl6V4) alloy surface modifications (coatings with silver (Ag), titanium nitride (TiN), pure titanium (cpTi), combinations of cpTi and hydroxyapatite (HA), combinations of cpTi and tricalcium phosphate (TCP), and a rough-blasted surface of TiAl6V4) have been investigated to assess their effects on biofilm development. Biofilms were grown, collected, and analyzed after 48 h to measure their protein and glucose content and the cell viability. Biofilm-associated genes were also monitored after 48 h of development. There was a distinct difference in the development of staphylococcal biofilms on the surfaces of the different types of alloy. According to the findings of this study, the base alloy TiAl6V4 and the TiN-coated surface are the most promising materials for biofilm reduction. Rough surfaces are most favorable when it comes to bacterial infections because they allow an easy attachment of pathogenic organisms. Of all rough surfaces tested, rough-blasted TiAl6V4 was the most favorable as an implantation material; all the other rough surfaces showed more distinct signs of inducing the development of biofilms which displayed higher protein and polysaccharide contents. These results are supported by RT-qPCR measurements of biofilm associated genes for Staphylococcus aureus (icaA, icaC, fnbA, fnbB, clfB, atl) and Staphylococcus epidermidis (atle, aap).}, } @article {pmid34069596, year = {2021}, author = {Jayathilaka, EHTT and Rajapaksha, DC and Nikapitiya, C and De Zoysa, M and Whang, I}, title = {Antimicrobial and Anti-Biofilm Peptide Octominin for Controlling Multidrug-Resistant Acinetobacter baumannii.}, journal = {International journal of molecular sciences}, volume = {22}, number = {10}, pages = {}, pmid = {34069596}, issn = {1422-0067}, support = {MABIK2021M00600//National Marine Biodiversity Institute of Korea/ ; 2018R1A2B6007841//National Research Foundation of Korea/ ; 2019R1A2C1087028//National Research Foundation of Korea/ ; }, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/metabolism ; Animals ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Antimicrobial Cationic Peptides/metabolism/*pharmacology ; Biofilms/drug effects ; Drug Resistance, Multiple/drug effects ; Drug Resistance, Multiple, Bacterial/*drug effects ; Drug Synergism ; Kinetics ; Microbial Viability/drug effects ; Models, Animal ; Peptide Fragments/metabolism/*pharmacology ; Zebrafish ; }, abstract = {Acinetobacter baumannii is a serious nosocomial pathogen with multiple drug resistance (MDR), the control of which has become challenging due to the currently used antibiotics. Our main objective in this study is to determine the antibacterial and antibiofilm activities of the antimicrobial peptide, Octominin, against MDR A. baumannii and derive its possible modes of actions. Octominin showed significant bactericidal effects at a low minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of 5 and 10 µg/mL, respectively. Time-kill kinetic analysis and bacterial viability tests revealed that Octominin showed a concentration-dependent antibacterial activity. Field-emission scanning electron microscopy (FE-SEM) analysis revealed that Octominin treatment altered the morphology and membrane structure of A. baumannii. Propidium iodide (PI) and reactive oxygen species (ROS) generation assays showed that Octominin increased the membrane permeability and ROS generation in A. baumannii, thereby causing bacterial cell death. Further, a lipopolysaccharides (LPS) binding assay showed an Octominin concentration-dependent LPS neutralization ability. Biofilm formation inhibition and eradication assays further revealed that Octominin inhibited biofilm formation and showed a high biofilm eradication activity against A. baumannii. Furthermore, up to a concentration of 100 µg/mL, Octominin caused no hemolysis and cell viability changes in mammalian cells. An in vivo study in zebrafish showed that the Octominin-treated group had a significantly higher relative percentage survival (54.1%) than the untreated group (16.6%). Additionally, a reduced bacterial load and fewer alterations in histological analysis confirmed the successful control of A. baumannii by Octominin in vivo. Collectively, these data suggest that Octominin exhibits significant antibacterial and antibiofilm activities against the multidrug-resistant A. baumannii, and this AMP can be developed further as a potent AMP for the control of antibiotic resistance.}, } @article {pmid34069543, year = {2021}, author = {Wu, S and Liu, Y and Lei, L and Zhang, H}, title = {An Antisense yycF RNA Modulates Biofilm Organization of Methicillin-Resistant Staphylococcus aureus and Pathogenicity in a Rat Model of Osteomyelitis.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {34069543}, issn = {2079-6382}, support = {2019YFS0270; 2021YJ0455//Sichuan Provincial Natural Science Foundation of China/ ; }, abstract = {Staphylococcus aureus (S. aureus) is one of most common opportunistic pathogens and is attributed to several human infections. The increasing incidence of methicillin-resistant S. aureus (MRSA) is a serious clinical threat for osteomyelitis crisis. The YycFG two-component system of S. aureus regulates genes associated with biofilm formation. To investigate the potential role of an antisense yycF RNA in the regulation of transcription levels of yycF and associated effects on biofilm formation and pathogenicity, antisense yycF (ASyycF) RNA was detected by RT-PCR and 5' RACE assays. ASyycF overexpression mutants were constructed, and the biofilm biomass was determined by crystal violet microtiter assay and scanning electron microscopy (SEM). Quantitative RT-PCR and Western blotting analyses were used to detect whether ASyycF overexpression inhibited the transcription and translation of biofilm-related genes. Then, a rat tibial infective model was used to evaluate the pathogenicity of ASyycF overexpression in vivo. ASyycF transcription led to reductions in YycF production and biofilm formation. Overexpression of ASyycF inhibited the transcription and translation of biofilm-related genes. The sensitivity to vancomycin was improved in ASyycF-overexpressing MRSA. Furthermore, ASyycF inhibited MRSA invasion in a rat tibial infection model. From this study, the expression of the YycF protein was found to be inversely correlated with different levels of ASyycF transcription. The biofilm biomass and pathogenicity decreased in the ASyycF-overexpressing mutant. Thus, the current evidence may support ASyycF as a supplementary strategy for managing S. aureus and MRSA infections.}, } @article {pmid34067392, year = {2021}, author = {Konduri, R and Saiabhilash, CR and Shivaji, S}, title = {Biofilm-Forming Potential of Ocular Fluid Staphylococcus aureus and Staphylococcus epidermidis on Ex Vivo Human Corneas from Attachment to Dispersal Phase.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34067392}, issn = {2076-2607}, support = {: DST-SERB grant (SB/SO/HS/019/2014) , ICMR (2017-2836/CMB-BMS), DHR (YSS/2020/000193/PRCYSS)//DST-SERB grant (SB/SO/HS/019/2014) from Government of India to SS, ; ICMR (2017-2836/CMB-BMS), Government of India Senior Research fellowship to KR; DHR (YSS/2020/000193/PRCYSS), Ministry of Health and Family Welfare, Government of India Young Scientist/ ; }, abstract = {The biofilm-forming potential of Staphylococcus aureus and Staphylococcus epidermidis, isolated from patients with Endophthalmitis, was monitored using glass cover slips and cadaveric corneas as substrata. Both the ocular fluid isolates exhibited biofilm-forming potential by the Congo red agar, Crystal violet and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-(phenylamino) carbonyl-2H-tetra-zolium hydroxide (XTT) methods. Confocal microscopy demonstrated that the thickness of the biofilm increased from 4-120 h of biofilm formation. Scanning electron microscopic studies indicated that the biofilms grown on cover slips and ex vivo corneas of both the isolates go through an adhesion phase at 4 h followed by multilayer clumping of cells with intercellular connections and copious amounts of extracellular polymeric substance. Clumps subsequently formed columns and eventually single cells were visible indicative of dispersal phase. Biofilm formation was more rapid when the cornea was used as a substratum. In the biofilms grown on corneas, clumping of cells, formation of 3D structures and final appearance of single cells indicative of dispersal phase occurred by 48 h compared to 96-120 h when biofilms were grown on cover slips. In the biofilm phase, both were several-fold more resistant to antibiotics compared to planktonic cells. This is the first study on biofilm forming potential of ocular fluid S. aureus and S. epidermidis on cadaveric cornea, from attachment to dispersal phase of biofilm formation.}, } @article {pmid34067197, year = {2021}, author = {Carzaniga, T and Falchi, FA and Forti, F and Antoniani, D and Landini, P and Briani, F}, title = {Different csrA Expression Levels in C versus K-12 E. coli Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs.}, journal = {Microorganisms}, volume = {9}, number = {5}, pages = {}, pmid = {34067197}, issn = {2076-2607}, support = {na//Regione Lombardia-MIUR/ ; }, abstract = {Escherichia coli C is a strong biofilm producer in comparison to E. coli K-12 laboratory strains due to higher expression of the pgaABCD operon encoding the enzymes for the biosynthesis of the extracellular polysaccharide poly-β-1,6-N-acetylglucosamine (PNAG). The pgaABCD operon is negatively regulated at the post-transcriptional level by two factors, namely CsrA, a conserved RNA-binding protein controlling multiple pathways, and the RNA exonuclease polynucleotide phosphorylase (PNPase). In this work, we investigated the molecular bases of different PNAG production in C-1a and MG1655 strains taken as representative of E. coli C and K-12 strains, respectively. We found that pgaABCD operon expression is significantly lower in MG1655 than in C-1a; consistently, CsrA protein levels were much higher in MG1655. In contrast, we show that the negative effect exerted by PNPase on pgaABCD expression is much stronger in C-1a than in MG1655. The amount of CsrA and of the small RNAs CsrB, CsrC, and McaS sRNAs regulating CsrA activity is dramatically different in the two strains, whereas PNPase level is similar. Finally, the compensatory regulation acting between CsrB and CsrC in MG1655 does not occur in E. coli C. Our results suggest that PNPase preserves CsrA-dependent regulation by indirectly modulating csrA expression.}, } @article {pmid34067036, year = {2021}, author = {Grande, R and Carradori, S}, title = {Novel Biologically Active Molecules, Biomaterials, and Nanoparticles for Microbial Biofilm Control in Human Medicine.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {9}, pages = {}, pmid = {34067036}, issn = {1420-3049}, mesh = {Antifungal Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Bacteria/*drug effects ; Biocompatible Materials/*pharmacology ; Biofilms/*drug effects ; Electrochemistry ; Humans ; Nanoparticles/*chemistry ; }, abstract = {The aim of the present special issue, proposed by two Co-Guest Editors with expertise in Clinical Microbiology and Medicinal Chemistry, is to collect and disseminate some of the most significant and innovative contributions focused on biofilm removal strategies, based on the use of natural or synthetic compounds/molecules/peptides or nanoparticles as well as biofilm formation inhibition aimed at both the control and monitoring of biofilm infections in medicine, food, industry, and natural environments [...].}, } @article {pmid34066609, year = {2021}, author = {Hao, S and Yang, D and Zhao, L and Shi, F and Ye, G and Fu, H and Lin, J and Guo, H and He, R and Li, J and Chen, H and Khan, MF and Li, Y and Tang, H}, title = {EGCG-Mediated Potential Inhibition of Biofilm Development and Quorum Sensing in Pseudomonas aeruginosa.}, journal = {International journal of molecular sciences}, volume = {22}, number = {9}, pages = {}, pmid = {34066609}, issn = {1422-0067}, support = {2020YFH0143//Sichuan Province Science and Technology Support Program/ ; }, mesh = {Acyl-Butyrolactones/metabolism ; Animals ; Biofilms/drug effects/*growth & development ; Caenorhabditis elegans/drug effects/microbiology ; Catechin/*analogs & derivatives/pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Glycolipids/biosynthesis ; Microbial Sensitivity Tests ; Movement ; Peptide Hydrolases/metabolism ; Pseudomonas aeruginosa/drug effects/growth & development/*physiology ; Pyocyanine/biosynthesis ; Quorum Sensing/*drug effects/genetics ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa), one of the dangerous multidrug resistance pathogens, orchestrates virulence factors production through quorum sensing (QS). Since the exploration of QS inhibitors, targeting virulence to circumvent bacterial pathogenesis without causing significant growth inhibition is a promising approach to treat P. aeruginosa infections. The present study has evaluated the anti-QS and anti-infective activity of epigallocatechin-3-gallate (EGCG), a bioactive ingredient of the traditional green tea, against P. aeruginosa. EGCG showed significant inhibitory effects on the development of biofilm, protease, elastase activity, swimming, and swarming motility, which was positively related to the production of C4-AHL. The expression of QS-related and QS-regulated virulence factors genes was also evaluated. Quantitative PCR analysis showed that EGCG significantly reduced the expression of las, rhl, and PQS genes and was highly correlated with the alterations of C4-AHL production. In-vivo experiments demonstrated that EGCG treatment reduced P. aeruginosa pathogenicity in Caenorhabditis elegans (C. elegans). EGCG increased the survival of C. elegans by 23.25%, 30.04%, and 36.35% in a dose-dependent manner. The findings of this study strongly suggest that EGCG could be a potential candidate for QS inhibition as an anti-virulence compound against bacterial infection.}, } @article {pmid34066411, year = {2021}, author = {Walczak, M and Michalska-Sionkowska, M and Olkiewicz, D and Tarnawska, P and Warżyńska, O}, title = {Potential of Carvacrol and Thymol in Reducing Biofilm Formation on Technical Surfaces.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {9}, pages = {}, pmid = {34066411}, issn = {1420-3049}, support = {POWR.03.05.00-00-Z302/17-00//Universitas Copernicana Thoruniensis In Futuro- modernization of Nicolaus Copernicus University as part of the Integrated University Program/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Chemistry, Pharmaceutical/trends ; Cymenes/*pharmacology ; Food Technology/trends ; Hydrolysis ; Materials Testing ; *Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Stainless Steel ; Staphylococcus aureus/*drug effects ; Surface Properties ; Thymol/*pharmacology ; }, abstract = {Polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), and stainless steel (SS) are commonly used in medicine and food production technologies. During contact with microorganisms on the surface of these materials, a microbial biofilm is formed. The biofilm structure is difficult to remove and promotes the development of pathogenic bacteria. For this reason, the inhibition of biofilm formation in medical and food production environments is very important. For this purpose, five naturally occurring compounds were used for antimicrobial screening tests. The two with the best antimicrobial properties were chosen to inhibit the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. After 3 days of exposure, thymol reduced the amount of biofilm of Pseudomonas aeruginosa within the range of 70-77% and 52-75% for Staphylococcus aureus. Carvacrol inhibited the formation of biofilms by up to 74-88% for Pseudomonas aeruginosa and up to 86-100% for Staphylococcus aureus. Those phenols decreased the enzyme activity of the biofilm by up to 40-100%. After 10 days of exposure to thymol, biofilm formation was reduced by 80-100% for Pseudomonas aeruginosa and by about 79-100% for Staphylococcus aureus. Carvacrol reduced the amount of biofilm by up to 91-100% for Pseudomonas aeruginosa and up to 95-100% for Staphylococcus aureus.}, } @article {pmid34065384, year = {2021}, author = {Swolana, D and Kępa, M and Kabała-Dzik, A and Dzik, R and Wojtyczka, RD}, title = {Sensitivity of Staphylococcal Biofilm to Selected Compounds of Plant Origin.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {34065384}, issn = {2079-6382}, support = {PCN-2-019/K/0/K//Śląski Uniwersytet Medyczny/ ; }, abstract = {Staphylococcus epidermidis is a bacterium that belongs to the human microbiota. It is most plentiful on the skin, in the respiratory system, and in the human digestive tract. Moreover, it is the most frequently isolated microorganism belonging to the group of Coagulase Negative Staphylococci (CoNS). In recent years, it has been recognized as an important etiological factor of mainly nosocomial infections and infections related to the cardiovascular system. On the other hand, Staphylococcus aureus, responsible for in-hospital and out-of-hospital infections, is posing an increasing problem for clinicians due to its growing resistance to antibiotics. Biofilm produced by both of these staphylococcal species in the course of infection significantly impedes therapy. The ability to produce biofilm hinders the activity of chemotherapeutic agents-the only currently available antimicrobial therapy. This also causes the observed significant increase in bacterial resistance. For this reason, we are constantly looking for new substances that can neutralize microbial cells. In the present review, 58 substances of plant origin with antimicrobial activity against staphylococcal biofilm were replaced. Variable antimicrobial efficacy of the substances was demonstrated, depending on the age of the biofilm. An increase in the activity of the compounds occurred in proportion to increasing their concentration. Appropriate use of the potential of plant-derived compounds as an alternative to antibiotics may represent an important direction of change in the support of antimicrobial therapy.}, } @article {pmid34064924, year = {2021}, author = {Fasciana, T and Ciammaruconi, A and Gentile, B and Di Carlo, P and Virruso, R and Tricoli, MR and Palma, DM and Pitarresi, GL and Lista, F and Giammanco, A}, title = {Draft Genome Sequence and Biofilm Production of a Carbapenemase-Producing Klebsiella pneumoniae (KpR405) Sequence Type 405 Strain Isolated in Italy.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {34064924}, issn = {2079-6382}, abstract = {Rapid identification and characterization of multidrug-resistant Klebsiella pneumoniae strains is essential to diagnose severe infections in patients. In clinical routine practice, K. pneumoniae is frequently identified and characterized for outbreak investigation. Pulsed-field gel electrophoresis or multilocus sequence typing could be used, but, unfortunately, these methods are time-consuming, laborious, expensive, and do not provide any information about the presence of resistance and virulence genes. In recent years, the decreasing cost of next-generation sequencing and its easy use have led to it being considered a useful method, not only for outbreak surveillance but also for rapid identification and evaluation, in a single step, of virulence factors and resistance genes. Carbapenem-resistant strains of K. pneumoniae have become endemic in Italy, and in these strains the ability to form biofilms, communities of bacteria fixed in an extracellular matrix, can defend the pathogen from the host immune response as well as from antibiotics, improving its persistence in epithelial tissues and on medical device surfaces.}, } @article {pmid34064414, year = {2021}, author = {Asghari, E and Kiel, A and Kaltschmidt, BP and Wortmann, M and Schmidt, N and Hüsgen, B and Hütten, A and Knabbe, C and Kaltschmidt, C and Kaltschmidt, B}, title = {Identification of Microorganisms from Several Surfaces by MALDI-TOF MS: P. aeruginosa Is Leading in Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {5}, pages = {}, pmid = {34064414}, issn = {2076-2607}, support = {EFRE-1803FI12//European Regional Development Fund/ ; }, abstract = {New ecological trends and changes in consumer behavior are known to favor biofilm formation in household appliances, increasing the need for new antimicrobial materials and surfaces. Their development requires laboratory-cultivated biofilms, or biofilm model systems (BMS), which allow for accelerated growth and offer better understanding of the underlying formation mechanisms. Here, we identified bacterial strains in wildtype biofilms from a variety of materials from domestic appliances using matrix-assisted laser desorption/ionization-time of flight mass spectroscopy (MALDI-TOF-MS). Staphylococci and pseudomonads were identified by MALDI-TOF-MS as the main genera in the habitats and were analyzed for biofilm formation using various in vitro methods. Standard quantitative biofilm assays were combined with scanning electron microscopy (SEM) to characterize biofilm formation. While Pseudomonas putida, a published lead germ, was not identified in any of the collected samples, Pseudomonas aeruginosa was found to be the most dominant biofilm producer. Water-born Pseudomonads were dominantly found in compartments with water contact only, such as in detergent compartment and detergent enemata. Furthermore, materials in contact with the washing load are predominantly colonized with bacteria from the human.}, } @article {pmid34063935, year = {2021}, author = {Renard, A and Diene, SM and Courtier-Martinez, L and Gaillard, JB and Gbaguidi-Haore, H and Mereghetti, L and Quentin, R and Francois, P and Van Der Mee-Marquet, N}, title = {12/111phiA Prophage Domestication Is Associated with Autoaggregation and Increased Ability to Produce Biofilm in Streptococcus agalactiae.}, journal = {Microorganisms}, volume = {9}, number = {6}, pages = {}, pmid = {34063935}, issn = {2076-2607}, abstract = {CC17 Streptococcus agalactiae carrying group-A prophages is increasingly responsible for neonatal infections. To investigate the impact of the genetic features of a group-A prophage, we first conducted an in silico analysis of the genome of 12/111phiA, a group-A prophage carried by a strain responsible for a bloodstream infection in a parturient. This revealed a Restriction Modification system, suggesting a prophage maintenance strategy and five ORFs of interest for the host and encoding a type II toxin antitoxin system RelB/YafQ, an endonuclease, an S-adenosylmethionine synthetase MetK, and an StrP-like adhesin. Using the WT strain cured from 12/111phiA and constructing deleted mutants for the ORFs of interest, and their complemented mutants, we demonstrated an impact of prophage features on growth characteristics, cell morphology and biofilm formation. Our findings argue in favor of 12/111phiA domestication by the host and a role of prophage features in cell autoaggregation, glycocalyx and biofilm formation. We suggest that lysogeny may promote GBS adaptation to the acid environment of the vagina, consequently colonizing and infecting neonates.}, } @article {pmid34063691, year = {2021}, author = {Jabłońska-Wawrzycka, A and Rogala, P and Czerwonka, G and Michałkiewicz, S and Hodorowicz, M and Gałczyńska, K and Cieślak, B and Kowalczyk, P}, title = {Tuning Anti-Biofilm Activity of Manganese(II) Complexes: Linking Biological Effectiveness of Heteroaromatic Complexes of Alcohol, Aldehyde, Ketone, and Carboxylic Acid with Structural Effects and Redox Activity.}, journal = {International journal of molecular sciences}, volume = {22}, number = {9}, pages = {}, pmid = {34063691}, issn = {1422-0067}, support = {Project miniGrant UJK No. SMGR.RN .20.262.656, SMGR.RN .20.262.660, and SMGR.RN. .20.109.604 as well as statutory funds of the Kielanowski Institute of Animal Physiology and Nu-trition of the Polish Academy of Sciences//Polish Ministry of Science and Higher Education/ ; }, mesh = {Alcohols/chemistry ; Aldehydes/chemistry ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Carboxylic Acids/chemistry ; Coordination Complexes/*chemistry/pharmacology ; Gram-Positive Bacteria/drug effects ; Humans ; Ketones/chemistry ; Manganese/*chemistry ; Microbial Sensitivity Tests ; Oxidation-Reduction/drug effects ; Pseudomonas aeruginosa ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {The constantly growing resistance of bacteria to antibiotics and other antibacterial substances has led us to an era in which alternative antimicrobial therapies are urgently required. One promising approach is to target bacterial pathogens using metal complexes. Therefore, we investigated the possibility of utilizing series of manganese(II) complexes with heteroaromatic ligands: Alcohol, aldehyde, ketone, and carboxylic acid as inhibitors for biofilm formation of Pseudomonas aeruginosa. To complete the series mentioned above, Mn-dipyCO-NO3 with dipyridin-2-ylmethanone (dipyCO) was isolated, and then structurally (single-crystal X-ray analysis) and physicochemically characterized (FT-IR, TG, CV, magnetic susceptibility). The antibacterial activity of the compounds against representative Gram-negative and Gram-positive bacteria was also evaluated. It is worth highlighting that the results of the cytotoxicity assays performed (MTT, DHI HoloMonitorM4) indicate high cell viability of the human fibroblast (VH10) in the presence of the Mn(II) complexes. Additionally, the inhibition effect of catalase activity by the complexes was studied. This paper focused on such aspects as studying different types of intermolecular interactions in the crystals of the Mn(II) complexes as well as their possible effect on anti-biofilm activity, the structure-activity relationship of the Mn(II) complexes, and regularity between the electrochemical properties of the Mn(II) complexes and anti-biofilm activity.}, } @article {pmid34063685, year = {2021}, author = {Samuggam, S and Chinni, SV and Mutusamy, P and Gopinath, SCB and Anbu, P and Venugopal, V and Reddy, LV and Enugutti, B}, title = {Green Synthesis and Characterization of Silver Nanoparticles Using Spondias mombin Extract and Their Antimicrobial Activity against Biofilm-Producing Bacteria.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {9}, pages = {}, pmid = {34063685}, issn = {1420-3049}, support = {FRGS/1/2018/STG03/AIMST/02/1//Fundamental Research Grant Scheme, Ministry of Higher Education, Malaysia/ ; }, mesh = {Anacardiaceae/*chemistry ; Animals ; Anti-Bacterial Agents/*pharmacology ; Artemia ; Bacteria/drug effects ; *Biofilms ; Drug Resistance, Multiple, Bacterial/*drug effects ; Green Chemistry Technology ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Nanomedicine ; Plant Extracts/pharmacology ; Plant Leaves/chemistry ; Reactive Oxygen Species ; Silver/*chemistry ; Ultraviolet Rays ; }, abstract = {Multidrug resistant bacteria create a challenging situation for society to treat infections. Multidrug resistance (MDR) is the reason for biofilm bacteria to cause chronic infection. Plant-based nanoparticles could be an alternative solution as potential drug candidates against these MDR bacteria, as many plants are well known for their antimicrobial activity against pathogenic microorganisms. Spondias mombin is a traditional plant which has already been used for medicinal purposes as every part of this plant has been proven to have its own medicinal values. In this research, the S. mombin extract was used to synthesise AgNPs. The synthesized AgNPs were characterized and further tested for their antibacterial, reactive oxygen species and cytotoxicity properties. The characterization results showed the synthesized AgNPs to be between 8 to 50 nm with -11.52 of zeta potential value. The existence of the silver element in the AgNPs was confirmed with the peaks obtained in the EDX spectrometry. Significant antibacterial activity was observed against selected biofilm-forming pathogenic bacteria. The cytotoxicity study with A. salina revealed the LC50 of synthesized AgNPs was at 0.81 mg/mL. Based on the ROS quantification, it was suggested that the ROS production, due to the interaction of AgNP with different bacterial cells, causes structural changes of the cell. This proves that the synthesized AgNPs could be an effective drug against multidrug resistant bacteria.}, } @article {pmid34063146, year = {2021}, author = {Woźniak, A and Kruszewska, B and Pierański, MK and Rychłowski, M and Grinholc, M}, title = {Antimicrobial Photodynamic Inactivation Affects the Antibiotic Susceptibility of Enterococcus spp. Clinical Isolates in Biofilm and Planktonic Cultures.}, journal = {Biomolecules}, volume = {11}, number = {5}, pages = {}, pmid = {34063146}, issn = {2218-273X}, support = {2015/19/B/NZ7/02487//Narodowe Centrum Nauki (National Science Centre)/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Ciprofloxacin/pharmacology ; Combined Modality Therapy ; Daptomycin/pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial/drug effects ; Drug Synergism ; Enterococcus faecalis/*drug effects/growth & development ; Enterococcus faecium/*drug effects/growth & development ; Gentamicins/pharmacology ; Microbial Sensitivity Tests ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Plankton/drug effects ; }, abstract = {Enterococcus faecium and Enterococcus faecalis are opportunistic pathogens that can cause a vast variety of nosocomial infections. Moreover, E. faecium belongs to the group of ESKAPE microbes, which are the main cause of hospital-acquired infections and are especially difficult to treat because of their resistance to many antibiotics. Antimicrobial photodynamic inactivation (aPDI) represents an alternative to overcome multidrug resistance problems. This process requires the simultaneous presence of oxygen, visible light, and photosensitizing compounds. In this work, aPDI was used to resensitize Enterococcus spp. isolates to antibiotics. Antibiotic susceptibility testing according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations was combined with synergy testing methods recommended by the American Society for Microbiology. Two clinical isolates, E. faecalis and E. faecium, were treated with a combination of aPDI utilizing rose bengal (RB) or fullerene (FL) derivative as photosensitizers, antimicrobial blue light (aBL), and 10 recommended antibiotics. aPDI appeared to significantly impact the survival rate of both isolates, while aBL had no significant effect. The synergy testing results differed between strains and utilized methods. Synergy was observed for RB aPDI in combination with gentamycin, ciprofloxacin and daptomycin against E. faecalis. For E. faecium, synergy was observed between RB aPDI and gentamycin or ciprofloxacin, while for RB aPDI with vancomycin or daptomycin, antagonism was observed. A combination of FL aPDI gives a synergistic effect against E. faecalis only with imipenem. Postantibiotic effect tests for E. faecium demonstrated that this isolate exposed to aPDI in combination with gentamycin, streptomycin, tigecycline, doxycycline, or daptomycin exhibits delayed growth in comparison to untreated bacteria. The results of synergy testing confirmed the effectiveness of aPDI in resensitization of the bacteria to antibiotics, which presents great potential in the treatment of infections caused by multidrug-resistant strains.}, } @article {pmid34059945, year = {2021}, author = {Frazão Câmara, JV and Araujo, TT and Mendez, DAC and da Silva, NDG and de Medeiros, FF and Santos, LA and de Souza Carvalho, T and Reis, FN and Martini, T and Moraes, SM and Shibao, PYT and Groisman, S and Magalhães, AC and Henrique-Silva, F and Buzalaf, MAR}, title = {Effect of a sugarcane cystatin on the profile and viability of microcosm biofilm and on dentin demineralization.}, journal = {Archives of microbiology}, volume = {203}, number = {7}, pages = {4133-4139}, pmid = {34059945}, issn = {1432-072X}, mesh = {Animals ; *Biofilms/drug effects ; Cattle ; *Cystatins/pharmacology ; *Dentin/metabolism ; Humans ; *Microbial Viability/drug effects ; *Saccharum/chemistry ; Streptococcus mutans/drug effects ; }, abstract = {To analyze the effect of a sugarcane cystatin (CaneCPI-5) on the microbial profile and viability, as well as on the prevention of dentin demineralization using a microcosm biofilm model. Ninety bovine dentine specimens were divided into five experimental groups according with the solution they were treated for 60 s: (1) PBS (negative control), (2) 0.12% chlorhexidine (positive control), (3) Fluoride (500 ppm F, as NaF), (4) 0.025 mg/ml CaneCPI-5, and (5) 0.05 mg/ml CaneCPI-5. Specimens were incubated with inoculum (McBain's saliva plus human saliva) in the first 8 h, and from then on, they were exposed to McBain saliva containing sucrose and daily treated (60 s) with the solutions for 5 days. Resazurin and colony-forming unit counting assays were performed. Dentin demineralization was measured by transverse micro-radiography (TMR). 0.12% chlorhexidine significantly reduced the metabolic activity of the microcosm biofilm in relation to the negative control and treated groups (p < 0.01). CHX and F significantly reduced the counts of total microorganisms, mutans group streptococci, and lactobacilli when compared with the negative control. None of the treatments was able to significantly reduce dentin demineralization in comparison with the negative control. In the model evaluated, CaneCPI-5 neither altered the microcosm biofilm profile and viability nor protected dentin against demineralization.}, } @article {pmid34059681, year = {2021}, author = {Sapireddy, V and Katuri, KP and Muhammad, A and Saikaly, PE}, title = {Competition of two highly specialized and efficient acetoclastic electroactive bacteria for acetate in biofilm anode of microbial electrolysis cell.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {47}, pmid = {34059681}, issn = {2055-5008}, mesh = {Acetates/*metabolism ; Bacteria/growth & development/*metabolism/ultrastructure ; Biofilms/*growth & development ; *Electrophysiological Phenomena ; Wastewater/microbiology ; Water Microbiology ; }, abstract = {Maintaining functional stability of microbial electrolysis cell (MEC) treating wastewater depends on maintaining functional redundancy of efficient electroactive bacteria (EAB) on the anode biofilm. Therefore, investigating whether efficient EAB competing for the same resources (electron donor and acceptor) co-exist at the anode biofilm is key for the successful application of MEC for wastewater treatment. Here, we compare the electrochemical and kinetic properties of two efficient acetoclastic EAB, Geobacter sulfurreducens (GS) and Desulfuromonas acetexigens (DA), grown as monoculture in MECs fed with acetate. Additionally, we monitor the evolution of DA and GS in co-culture MECs fed with acetate or domestic wastewater using fluorescent in situ hybridization. The apparent Monod kinetic parameters reveal that DA possesses higher jmax (10.7 ± 0.4 A/m[2]) and lower KS, app (2 ± 0.15 mM) compared to GS biofilms (jmax: 9.6 ± 0.2 A/m[2] and KS, app: 2.9 ± 0.2 mM). Further, more donor electrons are diverted to the anode for respiration in DA compared to GS. In acetate-fed co-culture MECs, DA (98% abundance) outcompete GS for anode-dependent growth. In contrast, both EAB co-exist (DA: 55 ± 2%; GS: 24 ± 1.1%) in wastewater-fed co-culture MECs despite the advantage of DA over GS based on kinetic parameters alone. The co-existence of efficient acetoclastic EAB with high current density in MECs fed with wastewater is significant in the context of functional redundancy to maintain stable performance. Our findings also provide insight to future studies on bioaugmentation of wastewater-fed MECs with efficient EAB to enhance performance.}, } @article {pmid34059077, year = {2021}, author = {Manandhar, S and Singh, A and Varma, A and Pandey, S and Shrivastava, N}, title = {Phenotypic and genotypic characterization of biofilm producing clinical coagulase negative staphylococci from Nepal and their antibiotic susceptibility pattern.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {20}, number = {1}, pages = {41}, pmid = {34059077}, issn = {1476-0711}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms/growth & development ; Clindamycin ; Coagulase/*genetics/metabolism ; Cross Infection/microbiology ; Drug Resistance, Multiple, Bacterial ; Genes, Bacterial/genetics ; *Genotype ; Humans ; Microbial Sensitivity Tests ; Nepal ; *Phenotype ; Staphylococcal Infections ; Staphylococcus/*drug effects/*genetics/isolation & purification/metabolism ; Staphylococcus epidermidis/drug effects/genetics/isolation & purification ; }, abstract = {BACKGROUND: Coagulase-negative staphylococci (CNS) survive as commensals of skin, anterior nares and external canals of human and were regarded as non-infectious pathogens. However, they are emerging as a major cause of nosocomial infectious due to their ability to form biofilms and high resistance to several classes of antibiotics. This study examines the biofilm forming abilities of 214 clinical CNS isolates using phenotypic and genotypic methods, and determines their antibiotic susceptibility patterns.

METHODS: A total of 214 clinical isolates collected from different clinical samples were identified as CNS and their antibiotic susceptibility determined by CLSI guidelines. The biofilm forming ability of all isolates was determined by three phenotypic methods; Congo red agar (CRA) method, tube adherence method (TM) and tissue culture plate (TCP) method and by genotypic method for the detection of icaAD genes.

RESULTS: Among all the isolates, S. epidermidis (57.5%) was found the most frequently, followed by S. saprophyticus (18.7%), S. haemolyticus (11.2%), S. hominis (7%), and S. capitis (5.6%). Antibiotic susceptibility pattern demonstrated 91.6% isolates were resistant to penicillin and 66.8% to cefoxitin while 91.1% isolates were susceptible to chloramphenicol. Constitutive and inducible clindamycin resistant phenotype as measured by D-test was seen among 28% and 14.5% of isolates respectively. Tissue culture plate method detected biofilm production in 42.1% isolate followed by 31.8% through tube method while 20.1% isolates were found to produce slime in Congo red agar method. The genotypic assay revealed presence of icaA and icaD genes in 19.2% isolates.

CONCLUSION: The study shows a high prevalence of biofilm formation and inducible clindamycin resistance in CNS isolates, indicating the importance of in-vitro biofilm production test and D-test in routine laboratory diagnostics. Implementation of efficient diagnostic techniques for detection of biofilm production in clinical samples can help manage staphylococcal infections and minimize risks of treatment failures in hospitals.}, } @article {pmid34058588, year = {2021}, author = {Zhou, Y and Li, R and Guo, B and Yu, N and Liu, Y}, title = {Cometabolism accelerated simultaneous ammoxidation and organics mineralization in an oxygen-based membrane biofilm reactor treating greywater under low dissolved oxygen conditions.}, journal = {The Science of the total environment}, volume = {789}, number = {}, pages = {147898}, doi = {10.1016/j.scitotenv.2021.147898}, pmid = {34058588}, issn = {1879-1026}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Denitrification ; Nitrification ; Nitrogen/analysis ; *Oxygen ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {Carbon/nitrogen ratio is an important parameter during the biological wastewater treatment. Our study emphasizes revealing the mechanisms of chemical oxygen demand/total nitrogen (COD/TN) ratio dependent improved greywater (GW) treatment in an oxygen based membrane biofilm reactor (O2-MBfR). Results showed that reducing COD/TN ratio from 40 to 20 g COD/g N by supplementing NH4Cl to GW improved the relative abundance of genera related to LAS-biodegradation (from 8.39% to 35.7%), nitrification (from 0.20% to 0.62%) and denitrification (from 3.01% to 7.59%). Reducing COD/TN ratio also led to an increase in the ammonia monooxygenase (AMO) activity (from 7.56 to 10.2 mg N/g VSS-h), as well as improved ammoxidation and linear alkylbenzene sulfonate (LAS) mineralization although the dissolved oxygen (DO) concentration and pH decreased. Much higher NH4[+] - N at lower COD/TN ratio (10 units) led to lower DO (0.13 ± 0.01 mg/L) and pH (6.72 ± 0.02), but the continuously increased AMO activity (up to 12.9 mg N/g VSS-h) enabled the cometabolism of ammoxidation and LAS mineralization, leading to the efficient removal of organics and nitrogen under the low DO condition.}, } @article {pmid34057367, year = {2021}, author = {Ghergab, A and Mohanan, N and Saliga, G and Brassinga, AKC and Levin, D and de Kievit, T}, title = {The effect of polyhydroxyalkanoates in Pseudomonas chlororaphis PA23 biofilm formation, stress endurance, and interaction with the protozoan predator Acanthamoeba castellanii.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {6}, pages = {476-490}, doi = {10.1139/cjm-2020-0497}, pmid = {34057367}, issn = {1480-3275}, mesh = {Acanthamoeba castellanii/*physiology ; Bacterial Adhesion ; Biofilms/*growth & development ; Brassica napus/microbiology ; Mutation ; Phenazines/metabolism ; Polyhydroxyalkanoates/genetics/*metabolism ; Polysaccharides, Bacterial/metabolism ; Pseudomonas chlororaphis/genetics/metabolism/*physiology ; Stress, Physiological/*physiology ; }, abstract = {Pseudomonas chlororaphis PA23 is a biocontrol agent capable of protecting canola against the fungal pathogen Sclerotinia sclerotiorum. In addition to producing antifungal compounds, this bacterium synthesizes and accumulates polyhydroxyalkanoate (PHA) polymers as carbon and energy storage compounds. Because the role of PHA in PA23 physiology is currently unknown, we investigated the impact of this polymer on stress resistance, adherence to surfaces, and interaction with the protozoan predator Acanthamoeba castellanii. Three PHA biosynthesis mutants were created, PA23phaC1, PA23phaC1ZC2, and PA23phaC1ZC2D, which accumulated reduced PHA. Our phenotypic assays revealed that PA23phaC1ZC2D produced less phenazine (PHZ) compared with the wild type (WT) and the phaC1 and phaC1ZC2 mutants. All three mutants exhibited enhanced sensitivity to UV irradiation, starvation, heat stress, cold stress, and hydrogen peroxide. Moreover, motility, exopolysaccharide production, biofilm formation, and root attachment were increased in strains with reduced PHA levels. Interaction studies with the amoeba A. castellanii revealed that the WT and the phaC1 and phaC1ZC2 mutants were consumed less than the phaC1ZC2D mutant, likely due to decreased PHZ production by the latter. Collectively these findings indicate that PHA accumulation enhances PA23 resistance to a number of stresses in vitro, which could improve the environmental fitness of this bacterium in hostile environments.}, } @article {pmid34057340, year = {2021}, author = {Carvalho, TS and Muçolli, D and Eick, S and Baumann, T}, title = {Salivary Pellicle Modification with Grape-seed Extract: In Vitro Study on the Effect on Bacterial Adhesion and Biofilm Formation.}, journal = {Oral health & preventive dentistry}, volume = {19}, number = {1}, pages = {301-309}, doi = {10.3290/j.ohpd.b1453013}, pmid = {34057340}, issn = {1757-9996}, mesh = {Bacterial Adhesion ; Biofilms ; Dental Pellicle ; *Grape Seed Extract/pharmacology ; Humans ; *Vitis ; }, abstract = {PURPOSE: Grape-seed extract (GSE) contains polyphenols that readily adhere to proteins and modify the acquired enamel pellicle (AEP). The first step in biofilm formation is bacterial adhesion to the AEP-covered enamel. The aim of this in vitro study was to test whether AEP modification with GSE, fluoride (F-), or their combination (GSE+F-) modulates bacterial adhesion, biofilm metabolism and composition, or cariogenic demineralisation of the enamel.

MATERIALS AND METHODS: The study comprised 3 parts: 1) single-strain Streptococcus gordonii species, 2) a five-species biofilm model, or 3) biofilm (re-)formation using the five-species biofilm model after removal of initial biofilm with toothbrushing. Human whole-mouth stimulated saliva was used to form an AEP on human enamel specimens. The AEP was incubated in water (control), or modified with GSE, F-, or GSE+F-. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and cariogenic demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 4 h or 22 h. Differences between groups were analysed with one-way ANOVA and post-hoc Bonferroni tests.

RESULTS: GSE and GSE+F- statistically significantly decreased single-strain S. gordonii adhesion, but had no relevant influence when the five-species biofilm model was used. In the biofilm (re-)formation model, GSE reduced bacterial adhesion compared to GSE+F-, while F- caused less cariogenic demineralisation than was found in the control group.

CONCLUSION: AEP modified with GSE retards S. gordonii adhesion, but it does not influence the formation, metabolism and composition of a cariogenic multi-species biofilm.}, } @article {pmid34056304, year = {2021}, author = {Gayani, B and Dilhari, A and Kottegoda, N and Ratnaweera, DR and Weerasekera, MM}, title = {Reduced Crystalline Biofilm Formation on Superhydrophobic Silicone Urinary Catheter Materials.}, journal = {ACS omega}, volume = {6}, number = {17}, pages = {11488-11496}, pmid = {34056304}, issn = {2470-1343}, abstract = {Crystalline biofilm formation in indwelling urinary catheters is a serious health problem as it creates a barrier for antibacterial coatings. This emphasizes the failure of antibacterial coatings that do not have a mechanism to reduce crystal deposition on catheter surfaces. In this study, trifluoropropyl spray-coated polydimethylsiloxane (TFP-PDMS) has been employed as an antibiofilm forming surface without any antibacterial agent. Here, TFP was coated on half-cured PDMS using the spray coating technique to obtain a durable superhydrophobic coating for a minimum five cycles of different sterilization methods. The crystalline biofilm-forming ability of Proteus mirabilis in artificial urine, under static and flow conditions, was assessed on a TFP-PDMS surface. In comparison to the commercially available silver-coated latex and silicone catheter surfaces, TFP-PDMS displayed reduced bacterial attachment over 14 days. Moreover, the elemental analysis determined by atomic absorption spectroscopy and energy-dispersive X-ray analysis revealed that the enhanced antibiofilm forming ability of TFP-PDMS was due to the self-cleaning activity of the surface. We believe that this modified surface will significantly reduce biofilm formation in indwelling urinary catheters and further warrant future clinical studies.}, } @article {pmid34054785, year = {2021}, author = {Srinivasan, R and Santhakumari, S and Poonguzhali, P and Geetha, M and Dyavaiah, M and Xiangmin, L}, title = {Bacterial Biofilm Inhibition: A Focused Review on Recent Therapeutic Strategies for Combating the Biofilm Mediated Infections.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {676458}, pmid = {34054785}, issn = {1664-302X}, abstract = {Biofilm formation is a major concern in various sectors and cause severe problems to public health, medicine, and industry. Bacterial biofilm formation is a major persistent threat, as it increases morbidity and mortality, thereby imposing heavy economic pressure on the healthcare sector. Bacterial biofilms also strengthen biofouling, affecting shipping functions, and the offshore industries in their natural environment. Besides, they accomplish harsh roles in the corrosion of pipelines in industries. At biofilm state, bacterial pathogens are significantly resistant to external attack like antibiotics, chemicals, disinfectants, etc. Within a cell, they are insensitive to drugs and host immune responses. The development of intact biofilms is very critical for the spreading and persistence of bacterial infections in the host. Further, bacteria form biofilms on every probable substratum, and their infections have been found in plants, livestock, and humans. The advent of novel strategies for treating and preventing biofilm formation has gained a great deal of attention. To prevent the development of resistant mutants, a feasible technique that may target adhesive properties without affecting the bacterial vitality is needed. This stimulated research is a rapidly growing field for applicable control measures to prevent biofilm formation. Therefore, this review discusses the current understanding of antibiotic resistance mechanisms in bacterial biofilm and intensely emphasized the novel therapeutic strategies for combating biofilm mediated infections. The forthcoming experimental studies will focus on these recent therapeutic strategies that may lead to the development of effective biofilm inhibitors than conventional treatments.}, } @article {pmid34054768, year = {2021}, author = {Stuermer, EK and Plattfaut, I and Dietrich, M and Brill, F and Kampe, A and Wiencke, V and Ulatowski, A and Geffken, M and Rembe, JD and Naumova, EA and Debus, SE and Smeets, R}, title = {In vitro Activity of Antimicrobial Wound Dressings on P. aeruginosa Wound Biofilm.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {664030}, pmid = {34054768}, issn = {1664-302X}, abstract = {The treatment of acute and chronic infected wounds with residing biofilm still poses a major challenge in medical care. Interactions of antimicrobial dressings with bacterial load, biofilm matrix and the overall protein-rich wound microenvironment remain insufficiently studied. This analysis aimed to extend the investigation on the efficacy of a variety of antimicrobial dressings using an in vitro biofilm model (lhBIOM) mimicking the specific biofilm-environment in human wounds. Four wound dressings containing polyhexanide (PHMB), octendine di-hydrochloride (OCT), cadexomer-iodine (C-IOD) or ionic silver (AG) were compared regarding their antimicrobial efficacy. Quantitative analysis was performed using a quantitative suspension method, separately assessing remaining microbial counts within the solid biofilm as well as the dressing eluate (representing the absorbed wound exudate). Dressing performance was tested against P. aeruginosa biofilms over the course of 6 days. Scanning electron microscopy (SEM) was used to obtain qualitative visualization on changes in biofilm structure. C-IOD demonstrated superior bacterial reduction. In comparison it was the only dressing achieving a significant reduction of more than 7 log10 steps within 3 days. Neither the OCT- nor the AG-containing dressing exerted a distinct and sustained antimicrobial effect. PHMB achieved a non-significant microbicidal effect (1.71 ± 0.31 log10 steps) at day 1. Over the remaining course (6 days) it demonstrated a significant microbistatic effect compared to OCT, AG and the control. Quantitative results in the dressing eluate correlate with those of the solid biofilm model. Overall, AG- and OCT-containing dressings did not achieve the expected anti-biofilm efficacy, while C-IOD performed best. Chemical interaction with the biofilms extrapolymeric substance (EPS), visualized in the SEM, and dressing configuration (agent concentration and release pattern) are suspected to be responsible. The unexpected low and diverse results of the tested antimicrobial dressings indicate a necessity to rethink non-debridement anti-biofilm therapy. Focussing on the combination of biofilm-disruptive (for EPS structure) and antimicrobial (for residing microorganisms) features, as with C-IOD, using dehydration and iodine, appears reasonably complementary and an optimal solution, as suggested by the here presented in vitro data.}, } @article {pmid34052491, year = {2021}, author = {Cheng, Z and Jiang, X and Cui, Z and Jia, H and Wang, J}, title = {The characteristic of electrode of degradation of bio-electrochemical system based on in-situ ultrasonic monitoring: Biofilm and ion precipitation.}, journal = {The Science of the total environment}, volume = {789}, number = {}, pages = {147987}, doi = {10.1016/j.scitotenv.2021.147987}, pmid = {34052491}, issn = {1879-1026}, mesh = {*Biofilms ; Electricity ; Electrodes ; *Ultrasonics ; }, abstract = {Electrode interface behavior is a decisive factor affecting the performance of bio-electrochemical systems, and traditional monitoring methods cannot provide real-time feedback. Therefore, in situ ultrasonic monitoring was performed to continuously monitor the formation process of electroactive biofilm and salt precipitation on the cathode surface. The results showed that biofilm was attached to the cathode surface first. Then, Ca[2+] and Mg[2+] precipitation gradually invaded the biofilm and accumulated between the cathode and the biofilm. The electrochemical performance of the biofilm adhesion and initial ion invasion process was improved. However, the electrochemical performance of the precipitation layer was decreased, while the operation time increases. In this paper, based on the air cathode scaling analyzing a new method for monitoring the electrode interface of bio-electrochemical system was provided, and the performance was recovered by using reverse electric field.}, } @article {pmid34050725, year = {2021}, author = {He, Y and Abdi, M and Trindade, GF and Begines, B and Dubern, JF and Prina, E and Hook, AL and Choong, GYH and Ledesma, J and Tuck, CJ and Rose, FRAJ and Hague, RJM and Roberts, CJ and De Focatiis, DSA and Ashcroft, IA and Williams, P and Irvine, DJ and Alexander, MR and Wildman, RD}, title = {Exploiting Generative Design for 3D Printing of Bacterial Biofilm Resistant Composite Devices.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {8}, number = {15}, pages = {e2100249}, pmid = {34050725}, issn = {2198-3844}, support = {103884/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; EP/P031684/1//Engineering and Physical Sciences Research Council/ ; EP/L015072/1//Engineering and Physical Sciences Research Council/ ; //UK Research and Innovation/ ; EP/I033335/2//Engineering and Physical Sciences Research Council/ ; 103882/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; EP/N024818/1//Engineering and Physical Sciences Research Council/ ; }, mesh = {*Biofilms ; Equipment and Supplies/*microbiology ; Ink ; *Printing, Three-Dimensional ; }, abstract = {As the understanding of disease grows, so does the opportunity for personalization of therapies targeted to the needs of the individual. To bring about a step change in the personalization of medical devices it is shown that multi-material inkjet-based 3D printing can meet this demand by combining functional materials, voxelated manufacturing, and algorithmic design. In this paper composite structures designed with both controlled deformation and reduced biofilm formation are manufactured using two formulations that are deposited selectively and separately. The bacterial biofilm coverage of the resulting composites is reduced by up to 75% compared to commonly used silicone rubbers, without the need for incorporating bioactives. Meanwhile, the composites can be tuned to meet user defined mechanical performance with ±10% deviation. Device manufacture is coupled to finite element modelling and a genetic algorithm that takes the user-specified mechanical deformation and computes the distribution of materials needed to meet this under given load constraints through a generative design process. Manufactured products are assessed against the mechanical and bacterial cell-instructive specifications and illustrate how multifunctional personalization can be achieved using generative design driven multi-material inkjet based 3D printing.}, } @article {pmid34050329, year = {2021}, author = {Choudhary, D and Cassaro, CJ}, title = {Digging deeper in the biofilm.}, journal = {Nature reviews. Microbiology}, volume = {19}, number = {8}, pages = {484}, pmid = {34050329}, issn = {1740-1534}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects/*growth & development ; Cholera/*drug therapy ; Humans ; Image Processing, Computer-Assisted/methods ; Microscopy, Confocal/methods ; Tetracycline/*therapeutic use ; Vibrio cholerae/*drug effects/*pathogenicity ; }, } @article {pmid34048890, year = {2021}, author = {Usmani, Y and Ahmed, A and Faizi, S and Versiani, MA and Shamshad, S and Khan, S and Simjee, SU}, title = {Antimicrobial and biofilm inhibiting potential of an amide derivative [N-(2', 4'-dinitrophenyl)-3β-hydroxyurs-12-en-28-carbonamide] of ursolic acid by modulating membrane potential and quorum sensing against colistin resistant Acinetobacter baumannii.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {104997}, doi = {10.1016/j.micpath.2021.104997}, pmid = {34048890}, issn = {1096-1208}, mesh = {*Acinetobacter baumannii ; Amides ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Colistin/pharmacology ; Membrane Potentials ; Microbial Sensitivity Tests ; Quorum Sensing ; Triterpenes ; }, abstract = {Acinetobacter baumannii is Gram-negative, an opportunistic pathogen responsible for life-threatening ventilator-associated pneumonia. World Health Organization (WHO) enlisted it as a priority pathogen for which therapeutic options need speculations. Biofilm further benefits this pathogen and aids 100-1000 folds more resistant against antimicrobials and the host immune system. In this study, ursolic acid (1) and its amide derivatives (2-4) explored for their antimicrobial and antibiofilm potential against colistin-resistant A. baumannii (CRAB) reference and clinical strains. Viability, crystal violet, microscopic, and gene expression assays further detailed the active compounds' antimicrobial and biofilm inhibition potential. Compound 4 [N-(2',4'-dinitrophenyl)-3β-hydroxyurs-12-en-28-carbonamide)], a synthetic amide derivate of ursolic acid significantly inhibits bacterial growth with MIC in the range of 78-156 μg/mL against CRAB isolates. This compound failed to completely kill the CRAB isolates even at 500 μg/mL concentration, suggesting the compound's anti-virulence and bacteriostatic nature. Short and prolonged exposure of 4 inhibited or delayed the bacterial growth at sub MIC, MIC, and 2× MIC, as evident in time-kill and post-antibacterial assay. It significantly inhibited and eradicated >70% of biofilm formation at MIC and sub MIC levels compared to colistin required in high concentrations. Microscopic analysis showed disintegrated biofilm after treatment with the 4 further strengthened its antibiofilm potential. Atomic force microscopy (AFM) hinted the membrane disrupting effect of 4 at MIC's. Further it was confirmed by DiBAC4 using fluorescence-activating cells sorting (FACS), suggesting a depolarized membrane at MIC. Gene expression analysis also supported our data as it showed reduced expression of biofilm-forming (bap) and quorum sensing (abaR) genes after treatment with sub MIC of 4. The results suggest that 4 significantly inhibit bacterial growth and biofilm mode of colistin-resistant A. baumannii. Thus, further studies are required to decipher the complete mechanism of action to develop 4 as a new pharmacophore against A. baumannii.}, } @article {pmid34048334, year = {2021}, author = {Diepoltová, A and Konečná, K and Janďourek, O and Nachtigal, P}, title = {Study of the impact of cultivation conditions and peg surface modification on the in vitro biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis in a system analogous to the Calgary biofilm device.}, journal = {Journal of medical microbiology}, volume = {70}, number = {5}, pages = {}, doi = {10.1099/jmm.0.001371}, pmid = {34048334}, issn = {1473-5644}, mesh = {Animals ; Bacteriological Techniques/*instrumentation/methods ; Biofilms/classification/drug effects/*growth & development ; Biomass ; Culture Media/chemistry/pharmacology ; Extracellular Polymeric Substance Matrix/classification/drug effects ; Humans ; Species Specificity ; Staphylococcus/classification/drug effects/*physiology ; }, abstract = {Introduction. Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) are the most common pathogens from the genus Staphylococcus causing biofilm-associated infections. Generally, biofilm-associated infections represent a clinical challenge. Bacteria in biofilms are difficult to eradicate due to their resistance and serve as a reservoir for recurring persistent infections.Gap Statement. A variety of protocols for in vitro drug activity testing against staphylococcal biofilms have been introduced. However, there are often fundamental differences. All these differences in methodical approaches can then be reflected in the form of discrepancies between results.Aim. In this study, we aimed to develop optimal conditions for staphylococcal biofilm formation on pegs. The impact of peg surface modification was also studied.Methodology. The impact of tryptic soy broth alone or supplemented with foetal bovine serum (FBS) or human plasma (HP), together with the impact of the inoculum density of bacterial suspensions and the shaking versus the static mode of cultivation, on total biofilm biomass production in SA and SE reference strains was studied. The surface of pegs was modified with FBS, HP, or poly-l-lysine (PLL). The impact on total biofilm biomass was evaluated using the crystal violet staining method and statistical data analysis.Results. Tryptic soy broth supplemented with HP together with the shaking mode led to crucial potentiation of biofilm formation on pegs in SA strains. The SE strain did not produce biofilm biomass under the same conditions on pegs. Preconditioning of peg surfaces with FBS and HP led to a statistically significant increase in biofilm biomass formation in the SE strain.Conclusion. Optimal cultivation conditions for robust staphylococcal biofilm formation in vitro might differ among different bacterial strains and methodical approaches. The shaking mode and supplementation of cultivation medium with HP was beneficial for biofilm formation on pegs for SA (ATCC 29213) and methicillin-resistant SA (ATCC 43300). Peg conditioning with HP and PLL had no impact on biofilm formation in either of these strains. Peg coating with FBS showed an adverse effect on the biofilm formation of these strains. By contrast, there was a statistically significant increase in biofilm biomass production on pegs coated with FBS and HP for SE (ATCC 35983).}, } @article {pmid34047549, year = {2021}, author = {He, C and Sampers, I and Van de Walle, D and Dewettinck, K and Raes, K}, title = {Encapsulation of Lactobacillus in Low-Methoxyl Pectin-Based Microcapsules Stimulates Biofilm Formation: Enhanced Resistances to Heat Shock and Simulated Gastrointestinal Digestion.}, journal = {Journal of agricultural and food chemistry}, volume = {69}, number = {22}, pages = {6281-6290}, doi = {10.1021/acs.jafc.1c00719}, pmid = {34047549}, issn = {1520-5118}, mesh = {Biofilms ; Capsules ; Digestion ; Heat-Shock Response ; *Pectins ; *Probiotics ; }, abstract = {Encapsulation is a common approach to improve the bacterial survival of probiotics. In this study, two new low-methoxyl pectins (CMP-6 and CMP-8) were used as coating materials to produce microcapsules (MCs) for the encapsulation of Lactobacillus acidophilus LMG9433[T], Lactobacillus casei LMG6904[T], and Lactobacillus rhamnosus LMG25859. A fermentation test showed that encapsulation did not influence the fermentation ability of lactobacilli. The biofilm formation of encapsulated lactobacilli was stimulated when an in situ cultivation was conducted on MCs, which was verified by cryo-SEM observation. The resultant biofilm-forming MCs (BMCs) contained high-density bacterial cells (∼10[10] CFU/mL). Compared to planktonic lactobacilli, pectin-based MCs showed significant protection for encapsulated lactobacilli from heat shock and simulated gastric digestion. Especially, benefiting from the biofilm formation, BMCs provided higher protection with enhanced resistance to heat shock, freeze-drying, and gastrointestinal digestion than MCs. Our result highlighted the superior bacterial resistances of biofilm-forming probiotics encapsulated in pectinate microcapsules.}, } @article {pmid34046916, year = {2021}, author = {Ma, J and Cheng, X and Xu, Z and Zhang, Y and Valle, J and Fan, S and Zuo, X and Lasa, I and Fang, X}, title = {Structural mechanism for modulation of functional amyloid and biofilm formation by Staphylococcal Bap protein switch.}, journal = {The EMBO journal}, volume = {40}, number = {14}, pages = {e107500}, pmid = {34046916}, issn = {1460-2075}, mesh = {Amyloid/*metabolism ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Calcium/metabolism ; Cell Aggregation/physiology ; Staphylococcus aureus/*growth & development/*metabolism ; }, abstract = {The Staphylococcal Bap proteins sense environmental signals (such as pH, [Ca[2+] ]) to build amyloid scaffold biofilm matrices via unknown mechanisms. We here report the crystal structure of the aggregation-prone region of Staphylococcus aureus Bap which adopts a dumbbell-shaped fold. The middle module (MM) connecting the N-terminal and C-terminal lobes consists of a tandem of novel double-Ca[2+] -binding motifs involved in cooperative interaction networks, which undergoes Ca[2+] -dependent order-disorder conformational switches. The N-terminal lobe is sufficient to mediate amyloid aggregation through liquid-liquid phase separation and maturation, and subsequent biofilm formation under acidic conditions. Such processes are promoted by disordered MM at low [Ca[2+] ] but inhibited by ordered MM stabilized by Ca[2+] binding, with inhibition efficiency depending on structural integrity of the interaction networks. These studies illustrate a novel protein switch in pathogenic bacteria and provide insights into the mechanistic understanding of Bap proteins in modulation of functional amyloid and biofilm formation, which could be implemented in the anti-biofilm drug design.}, } @article {pmid34046617, year = {2021}, author = {Weig, AW and Barlock, SL and O'Connor, PM and Marciano, OM and Smith, R and Ernst, RK and Melander, RJ and Melander, C}, title = {A scaffold hopping strategy to generate new aryl-2-amino pyrimidine MRSA biofilm inhibitors.}, journal = {RSC medicinal chemistry}, volume = {12}, number = {2}, pages = {293-296}, pmid = {34046617}, issn = {2632-8682}, support = {R01 DE022350/DE/NIDCR NIH HHS/United States ; }, abstract = {Infections that stem from bacterial biofilms are difficult to eradicate. Within a biofilm state, bacteria are upwards of 1000-fold more resistant to conventional antibiotics, necessitating the development of alternative approaches to treat biofilm-based infections. One such approach is the development of small molecule adjuvants that can inhibit/disrupt bacterial biofilms. When such molecules are paired with conventional antibiotics, these dual treatments present a combination approach to eradicate biofilm-based infections. Previously, we have demonstrated that small molecules containing either a 2-amino pyrimidine (2-AP) or a 2-aminoimidazole (2-AI) heterocycle are potent anti-biofilm agents. Herein, we now report a scaffold hopping strategy to generate new aryl 2-AP analogs that inhibit biofilm formation by methicillin-resistant Staphylococcus aureus (MRSA). These molecules also suppress colistin resistance in colistin resistant Klebsiella pneumoniae, lowering the minimum inhibitory concentration (MIC) by 32-fold.}, } @article {pmid34045521, year = {2021}, author = {Awadh, AA and Kelly, AF and Forster-Wilkins, G and Wertheim, D and Giddens, R and Gould, SW and Fielder, MD}, title = {Visualisation and biovolume quantification in the characterisation of biofilm formation in Mycoplasma fermentans.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {11259}, pmid = {34045521}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Microscopy, Confocal ; *Mycoplasma fermentans ; }, abstract = {The ability of mycoplasmas to persist on surfaces has been widely acknowledged, despite their fastidious nature. However, the organism's capability to form a recognisable biofilm structure has been identified more recently. In the current study Mycoplasma fermentans was found to adhere to the glass surface forming highly differentiated biofilm structures. The volumes of biofilm microcolonies were quantified and observed to be greater at late growth stage than those at early growth stage. The channel diameters within biofilms were measured with Scanning Electron Microscopy images and found to be consistent with the size observed in Confocal Laser Scanning Microscope images. The combination of imaging methods with 3D visualisation provides key findings that aid understanding of the mycoplasma biofilm formation and true biofilm architecture. The observations reported here provide better understanding of the persistence of these minimalist pathogens in nature and clinical settings.}, } @article {pmid34044049, year = {2021}, author = {Victoria, VM and Rocío, C and Silvina, E and Inés, EA and Lía, PN}, title = {Biofilm formation by LEE-negative Shiga Toxin-Producing Escherichia coli strains.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {105006}, doi = {10.1016/j.micpath.2021.105006}, pmid = {34044049}, issn = {1096-1208}, mesh = {*Biofilms ; Escherichia coli Proteins/genetics ; Phosphoproteins ; *Shiga-Toxigenic Escherichia coli/genetics/growth & development ; }, abstract = {Shiga toxin-producing Escherichia coli (STEC) include several serotypes isolated from cases of hemorrhagic colitis and, hemolytic uremic syndrome. Although O157:H7 is the most predominant STEC serotype, more than 100 non-O157 serogroups cause diseases in humans. Some STEC carry a Locus of Enterocyte Effacement (LEE-positive); however, STEC that do not carry LEE (LEE-negative) have also been associated with illness, mainly those harbouring the Locus of Adhesion and Autoaggregation (LAA). LAA carry some genes such as hes, iha, tpsA, and agn43, related with pathogenicity. One of them is the ability to form biofilms on different environments, which can contaminate food and generate infections while protecting themselves against adverse conditions. Considering that LAA could be responsible for some adherence mechanisms, the aims of this study were to compare different serogroup of LEE-negative STEC strains in their ability to form biofilms and to evaluate the participation of some genes encoding in LAA. A total of 348 LEE-negative STEC strains was analyzed. The presence of hes, iha, tpsA and agn43 were determined by monoplex PCR. From them, 48 STEC strains belonging to serogroups O113, O130, O171, O174 and, O178 were assayed for their ability to form biofilm. The most prevalent genes detected were agn43 (72.1%) and tpsA (69.5%). The iha and hes genes were present in 63.7% and 54% of the strains, respectively. Although all STEC strains were able to form biofilm, it was found a high variability between them. The relation between the biofilm formation and the presence of each gene was not statistically significant, suggesting that biofilm formation is independent of the presence of those genes. Highlighting that there is no treatment for HUS, it is once again notable that prevention measures and control strategies to prevent biofilm formation are important factors in reducing STEC transmission.}, } @article {pmid34044048, year = {2021}, author = {Yamani, L and Alamri, A and Alsultan, A and Alfifi, S and Ansari, MA and Alnimr, A}, title = {Inverse correlation between biofilm production efficiency and antimicrobial resistance in clinical isolates of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {104989}, doi = {10.1016/j.micpath.2021.104989}, pmid = {34044048}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; }, abstract = {This study assessed the correlation between biofilm formation in Pseudomonas aeruginosa strains with both the level of antibiotic resistance, and the number of virulence- and biofilm-related genes encoded. A total of sixty-six, non-replicate and prospectively collected P. aeruginosa strains were identified and tested. Potential ampD mutations that may impose resistance to extended-spectrum β-lactam (ESBL) agents were further explored. Of the sixty-six tested isolates, 40 demonstrated the multidrug resistance (MDR) phenotype, while twenty-six were non-MDR strains. An inverse correlation was observed between antibiotic resistance and the potential capacity to form biofilms. In addition, no correlation was observed between novel ampD mutations and the tendency for MDR isolates to acquire a β-lactam-resistant phenotype. The present study emphasizes the need for enhanced infection preventive measures in various hospital units, since both MDR and non-MDR P. aeruginosa isolates exhibited a high level of biofilm-forming capacity and the presence of virulence-associated genes.}, } @article {pmid34043827, year = {2021}, author = {Choi, MJ and Kim, MA and Choi, Y and Neelakantan, P and Yu, MK and Min, KS}, title = {A novel three-dimensionally printed model to assess biofilm removal by ultrasonically activated irrigation.}, journal = {International endodontic journal}, volume = {54}, number = {10}, pages = {1871-1877}, doi = {10.1111/iej.13579}, pmid = {34043827}, issn = {1365-2591}, support = {2019R1I1A3A01040706//National Research Foundation of Korea/ ; HI18C0432//Korea Health Industry Development Institute/Republic of Korea ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; Printing, Three-Dimensional ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite/pharmacology ; Therapeutic Irrigation ; }, abstract = {AIM: To apply an innovative three-dimensionally printed tooth model to investigate the efficacy of three ultrasonically activated irrigation (UAI) systems in removing multispecies biofilms from dentine samples.

METHODOLOGY: Three-dimensionally printed teeth with a curved root canal were fabricated with a standardized slot in the apical third of the root to achieve precision fit of human root dentine specimens. Multispecies biofilms including Enterococcus faecalis, Streptococcus mitis and Campylobacter rectus were developed in the root canal for 21 days. The canals were allocated to be irrigated with 1% sodium hypochlorite (NaOCl) using a syringe and needle or ultrasonically activated NaOCl with a stainless-steel file (Irrisafe), a conventional nickel-titanium (Ni-Ti) file (CK) or a blue heat-treated Ni-Ti file (Endosonic Blue). Infected root canals irrigated with distilled water served as controls. Bacterial reduction was determined by colony-forming unit (CFU) counting (n = 20), whilst biofilms were analysed using confocal laser scanning microscopy (n = 7) and field emission scanning electron microscopy. For CFU counting, the independent two-sample t-test (Welch's t-test) was examined to compare overall bacterial reduction amongst groups. For CLSM analysis, the data were analysed using one-way analysis of variance (ANOVA), followed by the Scheffé post hoc test. The p-values <.05 were considered to indicate statistical significance.

RESULTS: All groups in which NaOCl was ultrasonically activated had significantly lower CFU values than the syringe-and-needle irrigation and control groups (p < .05). Ultrasonic activation with the stainless-steel file and blue heat-treated Ni-Ti file significantly reduced the biofilm volume compared with other groups (p < .05). Overall, UAI with the blue heat-treated file resulted in the highest antibacterial and biofilm removal efficacy.

CONCLUSIONS: UAI with different inserts had differential antibiofilm effects. The blue heat-treated Ni-Ti ultrasonic insert resulted in the greatest antibacterial and biofilm removal from dentine in this standardized root canal model.}, } @article {pmid34042260, year = {2022}, author = {Skilbeck, MG and Mei, L and Mohammed, H and Cannon, RD and Farella, M}, title = {The effect of ligation methods on biofilm formation in patients undergoing multi-bracketed fixed orthodontic therapy - A systematic review.}, journal = {Orthodontics & craniofacial research}, volume = {25}, number = {1}, pages = {14-30}, doi = {10.1111/ocr.12503}, pmid = {34042260}, issn = {1601-6343}, mesh = {Biofilms ; Humans ; *Orthodontic Brackets ; Stainless Steel ; }, abstract = {BACKGROUND: Many modifications to fixed orthodontic appliances have been introduced to manage biofilm formation. The aim of this review was to investigate elastomeric ligation in comparison with stainless steel ligation and self-ligation with regard to microbiological and clinical indicators of biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.

METHODS: The MEDLINE and the EMBASE databases were searched up to February 2021 and supplemented by additional manual searches of bibliographies. Parallel-group and split-mouth randomized controlled trials (RCTs) comparing different ligation methods were identified. The Cochrane Risk of Bias-2 tool was applied to assess the quality of evidence.

RESULTS: A total of 11 RCTs were included in this review. Nine RCTs compared self-ligation and elastomeric ligation; two compared elastomeric ligation and stainless steel ligation. The included studies had either some concerns or were at a high risk of bias. Qualitative assessment of the studies identified that there were no significant differences in biofilm formation between elastomeric ligation and self-ligation, but that stainless steel ligation was less susceptible to biofilm formation than elastomeric ligation.

CONCLUSIONS: There were no significant differences between self-ligation and elastomeric ligation for biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances. Stainless steel ligation may accumulate less biofilm than elastomeric ligation; however, the clinical significance of the difference could not be evaluated. Further high-quality studies are required in order to determine which ligation method is better for managing biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.}, } @article {pmid34040029, year = {2021}, author = {Ilinov, A and Nishiyama, A and Namba, H and Fukushima, Y and Takihara, H and Nakajima, C and Savitskaya, A and Gebretsadik, G and Hakamata, M and Ozeki, Y and Tateishi, Y and Okuda, S and Suzuki, Y and Vinnik, YS and Matsumoto, S}, title = {Extracellular DNA of slow growers of mycobacteria and its contribution to biofilm formation and drug tolerance.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {10953}, pmid = {34040029}, issn = {2045-2322}, mesh = {Amikacin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Antitubercular Agents/pharmacology ; Biofilms/*growth & development ; DNA, Bacterial/*genetics/isolation & purification ; DNA, Viral/genetics/isolation & purification ; Extracellular Fluid/*chemistry ; Isoniazid/pharmacology ; Mycobacterium tuberculosis/drug effects/*genetics/growth & development ; Nontuberculous Mycobacteria/drug effects/*genetics/growth & development ; Prophages/genetics ; Species Specificity ; Whole Genome Sequencing ; }, abstract = {DNA is basically an intracellular molecule that stores genetic information and carries instructions for growth and reproduction in all cellular organisms. However, in some bacteria, DNA has additional roles outside the cells as extracellular DNA (eDNA), which is an essential component of biofilm formation and hence antibiotic tolerance. Mycobacteria include life-threating human pathogens, most of which are slow growers. However, little is known about the nature of pathogenic mycobacteria's eDNA. Here we found that eDNA is present in slow-growing mycobacterial pathogens, such as Mycobacterium tuberculosis, M. intracellulare, and M. avium at exponential growth phase. In contrast, eDNA is little in all tested rapid-growing mycobacteria. The physiological impact of disrupted eDNA on slow-growing mycobacteria include reduced pellicle formation, floating biofilm, and enhanced susceptibility to isoniazid and amikacin. Isolation and sequencing of eDNA revealed that it is identical to the genomic DNA in M. tuberculosis and M. intracellulare. In contrast, accumulation of phage DNA in eDNA of M. avium, suggests that the DNA released differs among mycobacterial species. Our data show important functions of eDNA necessary for biofilm formation and drug tolerance in slow-growing mycobacteria.}, } @article {pmid34038005, year = {2021}, author = {Yuan, Q and He, B and Qian, L and Littleton, H and Daigger, GT and van Loosdrecht, M and Wells, GF and Wang, K and Cai, H}, title = {Role of air scouring in anaerobic/anoxic tanks providing nitrogen removal by mainstream anammox conversion in a hybrid biofilm/suspended growth full-scale WWTP in China.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {10}, pages = {2198-2209}, doi = {10.1002/wer.1592}, pmid = {34038005}, issn = {1554-7531}, support = {2017ZX07102-003//Major Science and Technology Program for Water Pollution Control and Treatment of China/ ; }, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Wastewater/analysis ; }, abstract = {A full-scale wastewater treatment plant in China experienced unintentional anammox bacterial enrichment on biofilm carriers placed in the anaerobic and anoxic zones of an anaerobic/anoxic/oxic process under ambient temperatures and without bioaugmentation. Here, we show that microaerophilic conditions resulting from air scouring needed for biofilm carrier suspension in the anaerobic/anoxic zones can support a robust nitritation/anammox process. Results from an in situ on/off air scouring test showed that air scouring strongly induced both ammonia and total inorganic nitrogen removal in the anaerobic/anoxic zones. Ammonium concentration in the anaerobic and anoxic tanks remained constant or even slightly increased when air scouring was off, indicating that air scouring made a noticeable difference in nitrogen profiles in the anaerobic/anoxic zones. Various batch tests further indicated that partial denitrification is not likely to generate nitrite for anammox bacteria. Robust nitritation, and anammox on the carriers, can occur at low dissolved oxygen conditions, as measured in the full-scale facility. The observations show that mainstream deammonification without sidestream bioaugmentation at moderate temperature is feasible and further optimization by a more dedicated design can result in improved nitrogen removal in cases when chemical oxygen demand is limited in mainstream wastewater treatment. PRACTITIONER POINTS: Microaerophilic conditions in a full-scale IFAS reactor caused mainstream anammox in moderate temperate area. Robust nitritation, and anammox on the carriers, can occur at low dissolved oxygen conditions in anaerobic/anoxic tanks with air scouring. Anammox can function well with conventional nitrification and denitrification process at mainstream conditions for stable nitrogen removal.}, } @article {pmid34037088, year = {2021}, author = {Andrade, SA and Pratavieira, S and Bagnato, VS and Varotti, FP}, title = {Use of wide-field optical fluorescence for visualization of oral biofilm in a patient with peri-implant mucositis: a new approach.}, journal = {Einstein (Sao Paulo, Brazil)}, volume = {19}, number = {}, pages = {eRC5638}, pmid = {34037088}, issn = {2317-6385}, mesh = {Biofilms ; *Dental Implants/adverse effects ; Fluorescence ; Humans ; *Mucositis ; *Peri-Implantitis/diagnostic imaging/etiology ; }, abstract = {Peri-implant diseases, caused by bacteria from biofilm related to dental implants, are one of the main causes of late loss of implants. In this sense, peri-implant diseases are divided into peri-implant mucositis, when it affects only the soft tissues, and peri-implantitis, when there is a bone involvement, which can lead to the failure of dental implant therapy. Thus, biofilm removal is essential for peri-implant health, allowing long-term success in implant therapy. To improve the visualization of oral biofilm, which is usually transparent or colorless, disclosing agents have been routinely used. However, disclosing agents have allergenic potential and can cause staining extrinsically in restorative and prosthetic materials, leading to aesthetic impairment. Thus, the use of fluorescence has been studied as an alternative for visualization of oral biofilm. Therefore, this report describes the use of wide-field optical fluorescence for visualization of oral biofilm associated with implants and teeth, in a routine appointment and follow-up of a partially edentulous patient with peri-implant mucositis. In addition, this report showed wide-field optical fluorescence can be used in a clinical routine of care of patients with dental implants. In this sense, wide-field optical fluorescence allowed easy and immediate visualization of the mature oral biofilm for its adequate removal, evaluation of the quality of restoration to sealing of screw access-hole of implant and identification of cariogenic lesions, without risk of allergic reactions or staining of prostheses and restorations.}, } @article {pmid34036838, year = {2021}, author = {Rodrigues, NS and França, CM and Tahayeri, A and Ren, Z and Saboia, VPA and Smith, AJ and Ferracane, JL and Koo, H and Bertassoni, LE}, title = {Biomaterial and Biofilm Interactions with the Pulp-Dentin Complex-on-a-Chip.}, journal = {Journal of dental research}, volume = {100}, number = {10}, pages = {1136-1143}, pmid = {34036838}, issn = {1544-0591}, support = {UL1 TR002369/TR/NCATS NIH HHS/United States ; R01 DE026170/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025848/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biocompatible Materials/pharmacology ; Biofilms ; Calcium Compounds/pharmacology ; Dental Pulp ; Dentin ; Drug Combinations ; Humans ; *Lab-On-A-Chip Devices ; Oxides ; Silicates/pharmacology ; }, abstract = {Calcium silicate cements (CSCs) are the choice materials for vital pulp therapy because of their bioactive properties, promotion of pulp repair, and dentin bridge formation. Despite the significant progress made in understanding CSCs' mechanisms of action, the key events that characterize the early interplay between CSC-dentin-pulp are still poorly understood. To address this gap, a microfluidic device, the "tooth-on-a-chip," which was developed to emulate the biomaterial-dentin-pulp interface, was used to test 1) the effect of CSCs (ProRoot, Biodentine, and TheraCal) on the viability and proliferation of human dental pulp stem cells, 2) variations of pH, and 3) release within the pulp chamber of transforming growth factor-β (TGFβ) as a surrogate of the bioactive dentin matrix molecules. ProRoot significantly increased the extraction of TGFβ (P < 0.05) within 24 to 72 h and, along with Biodentine, induced higher cell proliferation (P > 0.05), while TheraCal decreased cell viability and provoked atypical changes in cell morphology. No correlation between TGFβ levels and pH was observed. Further, we established a biofilm of Streptococcus mutans on-chip to model the biomaterial-biofilm-dentin interface and conducted a live and dead assay to test the antimicrobial capability of ProRoot in real time. In conclusion, the device allows for direct characterization of the interaction of bioactive dental materials with the dentin-pulp complex on a model of restored tooth while enabling assessment of antibiofilm properties at the interface in real time that was previously unattainable.}, } @article {pmid34035436, year = {2021}, author = {Prudent, V and Demarre, G and Vazeille, E and Wery, M and Quenech'Du, N and Ravet, A and Dauverd-Girault, J and van Dijk, E and Bringer, MA and Descrimes, M and Barnich, N and Rimsky, S and Morillon, A and Espéli, O}, title = {The Crohn's disease-related bacterial strain LF82 assembles biofilm-like communities to protect itself from phagolysosomal attack.}, journal = {Communications biology}, volume = {4}, number = {1}, pages = {627}, pmid = {34035436}, issn = {2399-3642}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/growth & development ; Crohn Disease/metabolism/*microbiology ; Epithelial Cells/metabolism/*microbiology ; Escherichia coli/growth & development/pathogenicity ; Escherichia coli Infections/metabolism ; Gastrointestinal Microbiome ; Humans ; Intestinal Mucosa/microbiology ; Intestines ; Macrophages/metabolism/microbiology ; Mice ; Phagosomes/*metabolism/physiology ; RAW 264.7 Cells ; }, abstract = {Patients with Crohn's disease exhibit abnormal colonization of the intestine by adherent invasive E. coli (AIEC). They adhere to epithelial cells, colonize them and survive inside macrophages. It appeared recently that AIEC LF82 adaptation to phagolysosomal stress involves a long lag phase in which many LF82 cells become antibiotic tolerant. Later during infection, they proliferate in vacuoles and form colonies harboring dozens of LF82 bacteria. In the present work, we investigated the mechanism sustaining this phase of growth. We found that intracellular LF82 produced an extrabacterial matrix that acts as a biofilm and controls the formation of LF82 intracellular bacterial communities (IBCs) for several days post infection. We revealed the crucial role played by the pathogenicity island encoding the yersiniabactin iron capture system to form IBCs and for optimal LF82 survival. These results illustrate that AIECs use original strategies to establish their replicative niche within macrophages.}, } @article {pmid34034065, year = {2021}, author = {Miehle, M and Hackbarth, M and Gescher, J and Horn, H and Hille-Reichel, A}, title = {Biological biogas upgrading in a membrane biofilm reactor with and without organic carbon source.}, journal = {Bioresource technology}, volume = {335}, number = {}, pages = {125287}, doi = {10.1016/j.biortech.2021.125287}, pmid = {34034065}, issn = {1873-2976}, mesh = {Biofilms ; *Biofuels ; *Bioreactors ; Carbon ; Carbon Dioxide ; Hydrogen ; Methane ; }, abstract = {Biogas upgrading is a necessary step to minimize the CO2 of raw biogas and to make it suitable for gas liquefaction or introduction into the national gas grid. Biomethanation is a promising approach since it converts the CO2 to more methane on site, while taking advantage of the organisms responsible for biogas production in the first place. This study investigates the suitability of a pseudo-dead-end membrane biofilm reactor (MBfR) for ex-situ biogas upgrading using biogas as sole carbon source as well as for additional acetoclastic methanation when an organic carbon source is provided. Results prove that the concept of MBfR is especially advantageous for ex-situ hydrogenotrophic methanation of biogas CO2, yielding high product gas qualities of up to 99% methane. It is discussed that cross-flow membrane operation could reduce mass flux of inert methane through membranes, attached biofilms, and reactor liquid, and, thus, improve methanation space time yields.}, } @article {pmid34032940, year = {2021}, author = {Zayed, SM and Aboulwafa, MM and Hashem, AM and Saleh, SE}, title = {Biofilm formation by Streptococcus mutans and its inhibition by green tea extracts.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {73}, pmid = {34032940}, issn = {2191-0855}, abstract = {Dental Caries is considered one of the most existing and worldwide common diseases related to the oral cavity affecting both children and adults. Streptococcus mutans is the main cariogenic microorganism involved in the dental caries progression. Natural products such as herbal plants were found to have less side effects and economic value than those of the chemically synthesized antibiofilm agents. This study aimed to isolate Streptococcus mutans from different oral samples taken from saliva and dental plaques specimens to determine their capability for biofilm formation and to evaluate the antibiofilm activity of aqueous and alcoholic green tea extracts. The results revealed that 35, 4 and 1% of recovered dental plaque isolates exhibited strong, moderate and weak biofilm formation capabilities versus 26, 12 and 2% for those recovered from saliva. Two green tea extracts (aqueous and alcoholic) were tested for their antibiofilm formation activity against some selected S. mutans isolates. The results showed that the minimum biofilm inhibitory concentrations (MBICs) of the alcoholic and aqueous green tea extracts were in the range of 3.1 to 12.5 mg/ml and 6.5 to 50 mg/ml, respectively. Accordingly, green tea extracts can be incorporated in various oral preparations for preventing dental caries.}, } @article {pmid34032631, year = {2021}, author = {Zeng, J and Ji, M and Zhao, Y and Helmer Pedersen, T and Wang, H}, title = {Optimization of electrocoagulation process parameters for enhancing phosphate removal in a biofilm-electrocoagulation system.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {83}, number = {10}, pages = {2560-2574}, doi = {10.2166/wst.2021.132}, pmid = {34032631}, issn = {0273-1223}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Electrocoagulation ; Electrodes ; Hydrogen-Ion Concentration ; *Phosphates ; Waste Disposal, Fluid ; *Water Pollutants, Chemical ; }, abstract = {This study aimed to enhance the removal of phosphate in synthetic rural sewage by using a continuous electrocoagulation (EC) combined with biofilm process in an integrated system. Characteristic indexes of biofilm process effluent covering pH, dissolved oxygen (DO), suspended solids (SS), chemical oxygen demand (COD) and phosphate maintained a narrow fluctuation range and tended not readily to influence the phosphate removal of subsequent electrocoagulation. Three parameters including inter-electrode distance, current intensity and reaction time were selected to investigate the performance of enhancing phosphate removal. On the strength of single-factor tests, the Box-Behnken design (BBD) coupled with response surface methodology (RSM) was applied to investigate the individual and mutual interaction impacts of the major operating parameters and to optimize conditions. The optimum conditions were found to be inter-electrode distance of 1.8 cm, current density of 2.1 mA/cm[2] and EC reaction time of 34 min, and phosphate removal efficiency of 90.24% was achieved along with less than 1 mg/L in case of periodic polarity switching mode, which raised removal efficiency by 10.10% and reduced operating cost by 0.13 CNY/g PO4[-] compared to non-switching mode. The combination of biofilm processing and electrocoagulation treatment was proven to be a valid and feasible method for enhancing phosphate removal.}, } @article {pmid34031877, year = {2022}, author = {Polak, D and Shani-Kdoshim, S and Alias, M and Shapira, L and Stabholz, A}, title = {The in vitro efficacy of biofilm removal from titanium surfaces using Er:YAG laser: Comparison of treatment protocols and ablation parameters.}, journal = {Journal of periodontology}, volume = {93}, number = {1}, pages = {100-109}, doi = {10.1002/JPER.19-0574}, pmid = {34031877}, issn = {1943-3670}, mesh = {Anti-Bacterial Agents ; Biofilms ; Clinical Protocols ; *Dental Implants/microbiology ; *Lasers, Solid-State/therapeutic use ; Microscopy, Electron, Scanning ; Nylons ; Surface Properties ; Titanium ; }, abstract = {BACKGROUND: The aims of the present study were to compare the antibacterial effect of Er:YAG laser with other acceptable decontamination methods and to single out the optimal laser device parameters for effective bacterial elimination.

METHODS: A multispecies biofilm which was composed of Streptococcus sanguis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown on sandblasted and acid-etched (SLA, homogeneous moderately microrough, and nanosmooth surface) titanium disks. The biofilm was removed from the coated disks by hand curets, ultrasonic device, nylon brush (dental polishing prophy cup), or Er:YAG. Additionally, different parameter combinations of the laser machine were examined to reach an optimal lasing power for bacterial elimination/reduction. Residual biofilm samples were stained with bacterial live/dead staining and quantified using a fluorescent microscope.

RESULTS: A multispecies biofilm was accumulated on the SLA titanium surfaces exhibiting cluster distribution next to bacteria-poor areas. Hand curets, nylon brushes, and the ultrasonic device showed limited capability to effectively remove the biofilm from the SLA surfaces as opposed to the Er:YAG which displayed a superior ability to remove the biofilm. All Er:YAG parameter combinations that were evaluated as well as the tested "tip to target" distances showed similar excellent anti-biofilm effects. Furthermore, we observed that the Er:YAG capability of biofilm removal is not only due to its light emission, but depends on its water irrigation as well.

CONCLUSIONS: Er:YAG laser has an excellent biofilm removal capability compared with hand curets, ultrasonic devices, or nylon brushes even when low energy parameters and low power settings are used. Additionally, an excellent antibacterial effect can be reached using a non-contact mode of 1 to 5 mm "tip to target" distance.}, } @article {pmid34031036, year = {2021}, author = {Ludvik, DA and Bultman, KM and Mandel, MJ}, title = {Hybrid Histidine Kinase BinK Represses Vibrio fischeri Biofilm Signaling at Multiple Developmental Stages.}, journal = {Journal of bacteriology}, volume = {203}, number = {15}, pages = {e0015521}, pmid = {34031036}, issn = {1098-5530}, support = {R35 GM119627/GM/NIGMS NIH HHS/United States ; R35GM119627/GM/NIGMS NIH HHS/United States ; T32 GM008061/GM/NIGMS NIH HHS/United States ; T32GM008061/GM/NIGMS NIH HHS/United States ; T32GM008349/GM/NIGMS NIH HHS/United States ; T32 GM008349/GM/NIGMS NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/*enzymology/genetics/*growth & development/physiology ; Animals ; Bacterial Proteins/chemistry/genetics/*metabolism ; *Biofilms ; Decapodiformes/microbiology/physiology ; Histidine Kinase/chemistry/genetics/*metabolism ; Protein Domains ; Symbiosis ; }, abstract = {The symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and its exclusive light organ symbiont, Vibrio fischeri, provides a natural system in which to study host-microbe specificity and gene regulation during the establishment of a mutually beneficial symbiosis. Colonization of the host relies on bacterial biofilm-like aggregation in the squid mucus field. Symbiotic biofilm formation is controlled by a two-component signaling (TCS) system consisting of regulators RscS-SypF-SypG, which together direct transcription of the symbiosis polysaccharide Syp. TCS systems are broadly important for bacteria to sense environmental cues and then direct changes in behavior. Previously, we identified the hybrid histidine kinase BinK as a strong negative regulator of V. fischeri biofilm regulation, and here we further explore the function of BinK. To inhibit biofilm formation, BinK requires the predicted phosphorylation sites in both the histidine kinase (H362) and receiver (D794) domains. Furthermore, we show that RscS is not essential for host colonization when binK is deleted from strain ES114, and imaging of aggregate size revealed no benefit to the presence of RscS in a background lacking BinK. Strains lacking RscS still suffered in competition. Finally, we show that BinK functions to inhibit biofilm gene expression in the light organ crypts, providing evidence for biofilm gene regulation at later stages of host colonization. Overall, this study provides direct evidence for opposing activities of RscS and BinK and yields novel insights into biofilm regulation during the maturation of a beneficial symbiosis. IMPORTANCE Bacteria are often in a biofilm state, and transitions between planktonic and biofilm lifestyles are important for pathogenic, beneficial, and environmental microbes. The critical nature of biofilm formation during Vibrio fischeri colonization of the Hawaiian bobtail squid light organ provides an opportunity to study development of this process in vivo using a combination of genetic and imaging approaches. The current work refines the signaling circuitry of the biofilm pathway in V. fischeri, provides evidence that biofilm regulatory changes occur in the host, and identifies BinK as one of the regulators of that process. This study provides information about how bacteria regulate biofilm gene expression in an intact animal host.}, } @article {pmid34030016, year = {2021}, author = {Yang, W and Yao, J and He, Y and Huang, Y and Liu, H and Zhi, Y and Qian, S and Yan, X and Jian, S and Li, W}, title = {Nitrogen removal enhanced by benthic bioturbation coupled with biofilm formation: A new strategy to alleviate freshwater eutrophication.}, journal = {Journal of environmental management}, volume = {292}, number = {}, pages = {112814}, doi = {10.1016/j.jenvman.2021.112814}, pmid = {34030016}, issn = {1095-8630}, mesh = {Animals ; Biofilms ; Denitrification ; Ecosystem ; Eutrophication ; Fresh Water ; Geologic Sediments ; *Nitrogen/analysis ; *Water Pollutants, Chemical/analysis ; }, abstract = {Excessive nitrogen input into the water caused eutrophication thereby reducing biodiversity and degrades freshwater function. Nitrogen pollution in sediments is one key reason that makes eutrophication difficult to control. The physicochemical technologies such as dredging and coverage for sediment pollution easily destroyed and homogenized aquatic habitats. To alleviate freshwater eutrophication in ecological way, this work combined the functions of bioturbation and biofilm to test their effect on the removal of nitrogen from sediment and water. The total nitrogen removal by employing the coupled function (bioturbation + biofilm, SCB) was greater than that of the single function (bioturbation or biofilm). The mean efficiency of total nitrogen removal in SCB treatment was 3.19 times that of the control without chironomids nor biofilm medium. Chironomid bioturbation promoted nitrogen release from sediments to the overlying water. Biofilm enhanced the conversion and removal of nitrogen stirred up by chironomids, resulting the lowest concentration of total nitrogen in overlying water of SCB treatment. The enhancement of nitrogen removal may be due to the coupled function increased the abundance of denitrifying and anammox functional bacteria in sediment and biofilm. Therefore, the method of combining benthic animals with biofilm medium is not only a viable solution for reducing sedimentary nitrogen loading in freshwater ecosystems, but also a solution to mitigate eutrophication in the overlying water. The restoration and management for aquatic ecosystems should consider protecting habitat for benthic organisms while maintaining heterogeneity for biofilm.}, } @article {pmid34029865, year = {2021}, author = {Buakaew, T and Ratanatamskul, C}, title = {Effects of novel anaerobic baffled biofilm membrane bioreactor configurations on membrane fouling mitigation and microbial community in treating liquor condensate.}, journal = {Bioresource technology}, volume = {335}, number = {}, pages = {125310}, doi = {10.1016/j.biortech.2021.125310}, pmid = {34029865}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Membranes, Artificial ; *Microbiota ; Sewage ; *Wastewater ; }, abstract = {A novel anaerobic baffled biofilm-membrane bioreactor (AnBB-MBR) was developed to treat industrial liquor condensate. In order to minimize membrane fouling, three different reactor configurations of R1:No media (anaerobic baffled MBR), R2:FF (Fixed Film AnBB-MBR) and R3:FF + MVB (Fixed Film and Moving Bed AnBB-MBR) were evaluated at the same operating hydraulic retention time of 3 days. The specific fouling rates of the ceramic membranes were 0.98, 0.84 and 0.5 kPa/L/m[2] for R1:No media, R2:FF and R3:FF + MVB, respectively. The R2:FF and R3:FF + MVB reactors could mitigate the membrane fouling rates by 14.1% and 48.9%, compared to R1:No media due to biomass retention in the fixed film and mechanical scouring of the MVB. From the microbial community analysis, higher relative abundances of Methanosaeta were found in the biofilm whereas more Methanobacterium was found in the suspended sludge. Moreover, higher accumulations of humic and fulvic substances in the system could inhibit the methanogenic activity.}, } @article {pmid34027763, year = {2021}, author = {Dimou, I and Dritsas, S and Aggelopoulou, P and Vassilatou, K and Damianaki, S and Giaouris, E}, title = {Development of a herbal mouthwash containing a mixture of essential oils and plant extracts and in vitro testing of its antimicrobial efficiency against the planktonic and biofilm-enclosed cariogenic bacterium Streptococcus mutans.}, journal = {Biofouling}, volume = {37}, number = {4}, pages = {397-409}, doi = {10.1080/08927014.2021.1924693}, pmid = {34027763}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; In Vitro Techniques ; Microbial Sensitivity Tests ; Mouthwashes/pharmacology ; *Oils, Volatile/pharmacology ; Plankton ; Plant Extracts/pharmacology ; Streptococcus mutans ; }, abstract = {A herbal mouthwash containing essential oils of holy basil and mountain tea, extracts of St John's wort and European goldenrod (Bucovia™) and cetylpyridinium chloride, was developed and in vitro tested for its efficiency against biofilm formation by Streptococcus mutans, together with its eradicating activity against already preformed (48 h with saccharose) streptococcal biofilm. The minimum inhibitory (MIC) and bactericidal concentrations (MBC) of the final formulation, as well as of its individual components, were initially determined. The results revealed that the mouthwash needed to be applied at two-times its MIC (0.63% v.v[-1]) to completely inhibit biofilm formation by S. mutans, which was otherwise capable of developing a robust biofilm on the tested surface. Once fully developed, the matrix of the biofilm was found to contain a significant amount of exopolysaccharides protecting the cells, being impossible to eradicate even when exposed to pure mouthwash for 15 min, highlighting the great recalcitrance of biofilm-embedded S. mutans.}, } @article {pmid34026893, year = {2021}, author = {Pedersen, RR and Krömker, V and Bjarnsholt, T and Dahl-Pedersen, K and Buhl, R and Jørgensen, E}, title = {Biofilm Research in Bovine Mastitis.}, journal = {Frontiers in veterinary science}, volume = {8}, number = {}, pages = {656810}, pmid = {34026893}, issn = {2297-1769}, abstract = {Bovine mastitis is one of the most important diseases in the dairy industry and has detrimental impact on the economy and welfare of the animals. Further, treatment failure results in increased antibiotic use in the dairy industry, as some of these mastitis cases for unknown reasons are not resolved despite standard antibiotic treatment. Chronic biofilm infections are notoriously known to be difficult to eradicate with antibiotics and biofilm formation could be a possible explanation for mastitis cases that are not resolved by standard treatment. This paper reviews the current literature on biofilm in bovine mastitis research to evaluate the status and methods used in the literature. Focus of the current research has been on isolates from milk samples and investigation of their biofilm forming properties in vitro. However, in vitro observations of biofilm formation are not easily comparable with the in vivo situation inside the udder. Only two papers investigate the location and distribution of bacterial biofilms inside udders of dairy cows with mastitis. Based on the current knowledge, the role of biofilm in bovine mastitis is still unclear and more in vivo investigations are needed to uncover the actual role of biofilm formation in the pathogenesis of bovine mastitis.}, } @article {pmid34025605, year = {2021}, author = {Kergoat, L and Besse-Hoggan, P and Leremboure, M and Beguet, J and Devers, M and Martin-Laurent, F and Masson, M and Morin, S and Roinat, A and Pesce, S and Bonnineau, C}, title = {Environmental Concentrations of Sulfonamides Can Alter Bacterial Structure and Induce Diatom Deformities in Freshwater Biofilm Communities.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {643719}, pmid = {34025605}, issn = {1664-302X}, abstract = {Since the early 1920s, the intensive use of antibiotics has led to the contamination of the aquatic environment through diffuse sources and wastewater effluents. The antibiotics commonly found in surface waters include sulfamethoxazole (SMX) and sulfamethazine (SMZ), which belong to the class of sulfonamides, the oldest antibiotic class still in use. These antibiotics have been detected in all European surface waters with median concentrations of around 50 ng L[-1] and peak concentrations of up to 4-6 μg L[-1]. Sulfonamides are known to inhibit bacterial growth by altering microbial production of folic acid, but sub-lethal doses may trigger antimicrobial resistance, with unknown consequences for exposed microbial communities. We investigated the effects of two environmentally relevant concentrations (500 and 5,000 ng L[-1]) of SMZ and SMX on microbial activity and structure of periphytic biofilms in stream mesocosms for 28 days. Measurement of sulfonamides in the mesocosms revealed contamination levels of about half the nominal concentrations. Exposure to sulfonamides led to slight, transitory effects on heterotrophic functions, but persistent effects were observed on the bacterial structure. After 4 weeks of exposure, sulfonamides also altered the autotrophs in periphyton and particularly the diversity, viability and cell integrity of the diatom community. The higher concentration of SMX tested decreased both diversity (Shannon index) and evenness of the diatom community. Exposure to SMZ reduced diatom species richness and diversity. The mortality of diatoms in biofilms exposed to sulfonamides was twice that in non-exposed biofilms. SMZ also induced an increase in diatom teratologies from 1.1% in non-exposed biofilms up to 3% in biofilms exposed to SMZ. To our knowledge, this is the first report on the teratological effects of sulfonamides on diatoms within periphyton. The increase of both diatom growth rate and mortality suggests a high renewal of diatoms under sulfonamide exposure. In conclusion, our study shows that sulfonamides can alter microbial community structures and diversity at concentrations currently present in the environment, with unknown consequences for the ecosystem. The experimental set-up presented here emphasizes the interest of using natural communities to increase the ecological realism of ecotoxicological studies and to detect potential toxic effects on non-target species.}, } @article {pmid34023922, year = {2022}, author = {Kaur, M and Kumari, A and Singh, R}, title = {The Indigenous Volatile Inhibitor 2-Methyl-2-butene Impacts Biofilm Formation and Interspecies Interaction of the Pathogenic Mucorale Rhizopus arrhizus.}, journal = {Microbial ecology}, volume = {83}, number = {2}, pages = {506-512}, pmid = {34023922}, issn = {1432-184X}, support = {ECR/2016/000102//Early Career Research Award, Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Govt. of India/ ; DST/INSPIRE Faculty Award/2013/DST/INSPIRE/04/2013/000925//DST-INSPIRE Faculty Scheme, Govt. of India/ ; }, mesh = {Alkenes ; Biofilms ; *Rhizopus ; *Rhizopus oryzae ; Staphylococcus aureus ; }, abstract = {2-Methyl-2-butene has recently been reported to be a quorum-based volatile self-inhibitor of spore germination and growth in pathogenic Mucorale Rhizopus arrhizus. The present study aimed to elucidate if this compound can influence R. arrhizus biofilm formation and interspecies interaction. The compound was found to significantly decrease R. arrhizus biofilm formation (p < 0.001), with nearly 25% and 50% lesser biomass in the biofilms cultured with exposure to 4 and 32 µg/ml of 2-methyl-2-butene, respectively. The growth of pre-formed biofilms was also impacted, albeit to a lesser extent. Additionally, 2-methyl-2-butene was found to self-limit R. arrhizus growth during interspecies interaction with Staphylococcus aureus and was detected at a substantially greater concentration in the headspace of co-cultures (2338.75 µg/ml) compared with monocultures (69.52 µg/ml). Some of the C5 derivatives of this compound (3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-1-butyne) were also observed to partially mimic its action, such as inhibition of spore germination, but did not impact R. arrhizus biofilm formation. Finally, the treated R. arrhizus displayed changes in fungal morphology suggestive of cytoskeletal alterations, such as filopodia formation, blebs, increased longitudinal folds and/or corrugations, and finger-like and sheet-like surface protrusions, depending upon the concentration of the compound(s) and the planktonic or biofilm growth mode.}, } @article {pmid34022615, year = {2021}, author = {Wagner, EM and Fischel, K and Rammer, N and Beer, C and Palmetzhofer, AL and Conrady, B and Roch, FF and Hanson, BT and Wagner, M and Rychli, K}, title = {Bacteria of eleven different species isolated from biofilms in a meat processing environment have diverse biofilm forming abilities.}, journal = {International journal of food microbiology}, volume = {349}, number = {}, pages = {109232}, doi = {10.1016/j.ijfoodmicro.2021.109232}, pmid = {34022615}, issn = {1879-3460}, mesh = {Bacteria/classification/genetics/growth & development/*isolation & purification ; Biofilms/*growth & development ; Colony Count, Microbial ; Extracellular Polymeric Substance Matrix/chemistry/genetics ; Food Microbiology ; Food-Processing Industry ; Genome, Bacterial/genetics ; Locomotion/genetics ; Meat/*microbiology ; Species Specificity ; }, abstract = {Biofilms are formed by microorganisms protected by a self-produced matrix, most often attached to a surface. In the food processing environments biofilms endanger the product safety by the transmission of spoilage and pathogenic bacteria. In this study, we characterised the biofilm formation of the following eleven strains isolated from biofilms in a meat-processing environment: Acinetobacter harbinensis BF1, Arthrobacter sp. BF1, Brochothrix thermosphacta BF1, Carnobacterium maltaromaticum BF1, Kocuria salsicia BF1, Lactococcus piscium BF1, Microbacterium sp. BF1, Pseudomonas fragi BF1, Psychrobacter sp. BF1, Rhodococcus erythropolis BF1, Stenotrophomonas sp. BF1. We applied whole- genome sequencing and subsequent genome analysis to elucidate genetic features associated with the biofilm lifestyle. We furthermore determined the motility and studied biofilm formation on stainless steel using a static mono-species biofilm model mimicking the meat processing environment. The biomass and the EPS components carbohydrates, proteins and extracellular DNA (eDNA) of the biofilms were investigated after seven days at 10 °C. Whole-genome analysis of the isolates revealed that all strains except the Kocuria salsicia BF1 isolate, harboured biofilm associated genes, including genes for matrix production and motility. Genes involved in cellulose metabolism (present in 82% of the eleven strains) and twitching motility (present in 45%) were most frequently found. The capacity for twitching was confirmed using plate assays for all strains except Lactococcus piscium BF1, which showed the lowest motility behaviour. Differences in biofilm forming abilities could be demonstrated. The bacterial load ranged from 5.4 log CFU/cm[2] (Psychrobacter sp. isolate) to 8.7 log CFU/cm[2] (Microbacterium sp. isolate). The amount of the matrix components varied between isolates. In the biofilm of six strains we detected all three matrix components at different levels (carbohydrates, proteins and eDNA), in two only carbohydrates and eDNA, and in three only carbohydrates. Carbohydrates were detected in biofilms of all strains ranging from 0.5 to 4.3 μg glucose equivalents/cm[2]. Overall, the Microbacterium sp. strain showed the highest biofilm forming ability with high bacterial load (8.7 log CFU/cm[2]) and high amounts of carbohydrates (2.2 μg glucose equivalents/cm[2]), proteins (present in all experiments) and eDNA (549 ng/cm[2]). In contrast, Brochothrix thermosphacta was a weak biofilm former, showing low bacterial load and low levels of carbohydrates in the matrix (6.2 log CFU/cm[2] and 0.5 μg glucose equivalents/cm[2]). This study contributes to our understanding of the biofilm forming ability of bacteria highly abundant in the meat processing environment, which is crucial to develop strategies to prevent and reduce biofilm formation in the food producing environment.}, } @article {pmid34022356, year = {2021}, author = {Shui, Y and Jiang, Q and Lyu, X and Wang, L and Lin, Y and Ma, Q and Gong, T and Zeng, J and Yang, R and Li, Y}, title = {Inhibitory effects of sodium new houttuyfonate on growth and biofilm formation of Streptococcus mutans.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {104957}, doi = {10.1016/j.micpath.2021.104957}, pmid = {34022356}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Chlorhexidine ; *Streptococcus mutans ; Sulfonic Acids ; Virulence ; }, abstract = {The present study aimed to assess the impact of sodium new houttuyfonate (SNH) on growth and biofilm formation of Streptococcus mutans, and the combinatorial effects of SNH with cariostatic agents. The effects of SNH on S. mutans planktonic cultures were assessed by growth curve assay. The effects of SNH on S. mutans biofilm and extracellular polysaccharides (EPS) production were observed via crystal violet (CV) assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, colony-forming unit (CFU) counting assay, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Quantitative real-time polymerase chain reaction (qPCR) was applied to investigate the regulatory effects of SNH on the expression of virulence genes of S. mutans. Checkerboard microdilution assay was performed to investigate the combinatorial effects of SNH with two common cariostatic agents. SNH acted as an inhibitor on planktonic cell growth, biofilm formation and EPS production of S. mutans. SNH also downregulated the expression of gtfBCD and comDE systems and exhibited synergism with chlorhexidine (CHX). In conclusion, this study indicated a possibility for SNH to become an anticaries agents by its antimicrobial activity and synergistic effects with CHX against S. mutans.}, } @article {pmid34020940, year = {2021}, author = {Zuo, P and Yu, P and Alvarez, PJJ}, title = {Aminoglycosides Antagonize Bacteriophage Proliferation, Attenuating Phage Suppression of Bacterial Growth, Biofilm Formation, and Antibiotic Resistance.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {15}, pages = {e0046821}, pmid = {34020940}, issn = {1098-5336}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacillus Phages/*drug effects/growth & development ; Bacillus cereus/*drug effects/physiology/virology ; Bacteriophage T3/*drug effects/growth & development ; Biofilms/growth & development ; Drug Resistance, Bacterial/*drug effects ; Escherichia coli/*drug effects/physiology/virology ; Kanamycin/*pharmacology ; Neomycin/*pharmacology ; Tetracycline/pharmacology ; }, abstract = {The common cooccurrence of antibiotics and phages in both natural and engineered environments underscores the need to understand their interactions and implications for bacterial control and antibiotic resistance propagation. Here, aminoglycoside antibiotics that inhibit protein synthesis (e.g., kanamycin and neomycin) impeded the replication of coliphage T3 and Bacillus phage BSP, reducing their infection efficiency and mitigating their hindrance of bacterial growth, biofilm formation, and tolerance to antibiotics. For example, treatment with phage T3 reduced subsequent biofilm formation by Escherichia coli liquid cultures to 53% ± 5% of that of the no-phage control, but a smaller reduction of biofilm formation (89% ± 10%) was observed for combined exposure to phage T3 and kanamycin. Despite sharing a similar mode of action with aminoglycosides (i.e., inhibiting protein synthesis) and antagonizing phage replication, albeit to a lesser degree, tetracyclines did not inhibit bacterial control by phages. Phage T3 combined with tetracycline showed higher suppression of biofilm formation than when combined with aminoglycosides (25% ± 6% of the no-phage control). The addition of phage T3 to E. coli suspensions with tetracycline also suppressed the development of tolerance to tetracycline. However, this suppression of antibiotic tolerance development disappeared when tetracycline was replaced with 3 mg/liter kanamycin, corroborating the greater antagonism with aminoglycosides. Overall, this study highlights this overlooked antagonistic effect on phage proliferation, which may attenuate phage suppression of bacterial growth, biofilm formation, antibiotic tolerance, and maintenance of antibiotic resistance genes. IMPORTANCE The coexistence of residual antibiotics and phages is common in many environments, which underscores the need to understand their interactive effects on bacteria and the implications for antibiotic resistance propagation. Here, aminoglycosides acting as bacterial protein synthesis inhibitors impeded the replication of various phages. This alleviated the suppressive effects of phages against bacterial growth and biofilm formation and diminished bacterial fitness costs that suppress the emergence of tolerance to antibiotics. We show that changes in bacteria caused by environmentally relevant concentrations of sublethal antibiotics can affect phage-host dynamics that are commonly overlooked in vitro but can result in unexpected environmental consequences.}, } @article {pmid34020874, year = {2021}, author = {Huang, T and Zhao, J and Wang, S and Lei, L}, title = {Fast start-up and enhancement of partial nitritation and anammox process for treating synthetic wastewater in a sequencing bath biofilm reactor: Strategy and function of nitric oxide.}, journal = {Bioresource technology}, volume = {335}, number = {}, pages = {125225}, doi = {10.1016/j.biortech.2021.125225}, pmid = {34020874}, issn = {1873-2976}, mesh = {Ammonia ; *Ammonium Compounds ; Biofilms ; Bioreactors ; Nitric Oxide ; Nitrogen ; Oxidation-Reduction ; *Wastewater/analysis ; }, abstract = {In this study, the partial nitritation and anammox (PN-A) process was initiated within 30 days in a sequencing batch biofilm reactor (SBBR) by employing pre non-aeration and post non-aeration with fixed aeration rates. The average ammonia removal efficiency (ARE), total nitrogen removal efficiency (TNRE) of 98.5 ± 1.5% and 89.5 ± 1.6% were achieved. By doubling aeration rate and agitation rate and adopting pre non-aeration, the TNRR was promoted from 0.135 ± 0.013 kg N·m[-3]·d[-1] to 0.285 ± 0.015 kg N·m[-3]·d[-1], obtaining an average ARE and TNRE of 97.5 ± 1.5% and 85.5 ± 2.6%. Nitric oxide might induce anaerobic ammonia oxidation bacteria (AnAOB) during the start-up stage, and could be an indicator for synergetic state between ammonia oxidation bacteria (AOB) and AnAOB. Lower nitrous oxide emission factor of 0.51% was obtained. The abundance of AOB, AnAOB and nitrite oxidation bacteria (NOB) accounted for 1.6%, 19.3% and 0.3%, respectively.}, } @article {pmid34020643, year = {2021}, author = {Fernández-Calderón, MC and Hernández-González, L and Gómez-Navia, C and Blanco-Blanco, MT and Sánchez-Silos, R and Lucio, L and Pérez-Giraldo, C}, title = {Antifungal and anti-biofilm activity of a new Spanish extract of propolis against Candida glabrata.}, journal = {BMC complementary medicine and therapies}, volume = {21}, number = {1}, pages = {147}, pmid = {34020643}, issn = {2662-7671}, support = {IB16154//Consejería de Educación y Empleo, Junta de Extremadura/ ; GR18096//Consejería de Educación y Empleo, Junta de Extremadura/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida glabrata/*drug effects ; Microbial Sensitivity Tests ; Propolis/*pharmacology ; }, abstract = {BACKGROUND: Resistance to traditional antifungal agents is a considerable health problem nowadays, aggravated by infectious processes related to biofilm formation, usually on implantable devices. Therefore, it is necessary to identify new antimicrobial molecules, such as natural products, to develop new therapeutic strategies to prevent and eradicate these infections. One promising product is propolis, a natural resin produced by honeybees with substances from various botanical sources, beeswax and salivary enzymes. The aim of this work was to study the effect of a new Spanish ethanolic extract of propolis (SEEP) on growth, cell surface hydrophobicity, adherence and biofilm formation of Candida glabrata, a yeast capable of achieving high levels of resistance to available anti-fungal agents.

METHODS: The antifungal activity of SEEP was evaluated in the planktonic cells of 12 clinical isolates of C. glabrata. The minimum inhibitory concentration (MIC) of propolis was determined by quantifying visible growth inhibition by serial plate dilutions. The minimum fungicide concentration (MFC) was evaluated as the lowest concentration of propolis that produced a 95% decrease in cfu/mL, and is presented as MFC50 and MFC90, which corresponds to the minimum concentrations at which 50 and 90% of the C. glabrata isolates were inhibited, respectively. Influence on cell surface hydrophobicity (CSH) was determined by the method of microbial adhesion to hydrocarbons (MATH). The propolis effect on adhesion and biofilm formation was determined in microtiter plates by measurement of optical density (OD) and metabolic activity (XTT-assay) in the presence of sub-MIC concentrations of SEEP.

RESULTS: SEEP had antifungal capacity against C. glabrata isolates, with a MIC50 of 0.2% (v/v) and an MFC50 of 0.4%, even in azole-resistant strains. SEEP did not have a clear effect on surface hydrophobicity and adhesion, but an inhibitory effect on biofilm formation was observed at subinhibitory concentrations (0.1 and 0.05%) with a significant decrease in biofilm metabolism.

CONCLUSIONS: The novel Spanish ethanolic extract of propolis shows antifungal activity against C. glabrata, and decreases biofilm formation. These results suggest its possible use in the control of fungal infections associated with biofilms.}, } @article {pmid34020186, year = {2021}, author = {Chen, X and Huo, P and Liu, J and Li, F and Yang, L and Li, X and Wei, W and Liu, Y and Ni, BJ}, title = {Model predicted N2O production from membrane-aerated biofilm reactor is greatly affected by biofilm property settings.}, journal = {Chemosphere}, volume = {281}, number = {}, pages = {130861}, doi = {10.1016/j.chemosphere.2021.130861}, pmid = {34020186}, issn = {1879-1298}, mesh = {Biofilms ; *Bioreactors ; Membranes ; *Nitrous Oxide ; Reproducibility of Results ; Waste Disposal, Fluid ; }, abstract = {Even though modeling has been frequently used to understand the autotrophic deammonification-based membrane-aerated biofilm reactor (MABR), the relationships between system-specific biofilm property settings and model predicted N2O production have yet to be clarified. To this end, this study investigated the impacts of 4 key biofilm property settings (i.e., biofilm thickness/compactness, boundary layer thickness, diffusivity of soluble components in the biofilm structure, and biofilm discretization) on one-dimensional modeling of the MABR, with the focus on its N2O production. The results showed that biofilm thickness/compactness (200-1000 μm), diffusivity of soluble components in the biofilm structure (reduction factor of diffusivity: 0.2-0.9), and biofilm discretization (12-28 grid points) significantly influenced the simulated N2O production, while boundary layer thickness (0-300 μm) only played a marginal role. In the studied ranges of biofilm property settings, distinct upper and lower bounds of N2O production factor (i.e., the percentage ratio of N2O formed to NH4[+] removed, 5.5% versus 2.3%) could be predicted. In addition to the microbial community structure, the N2O production pathway contribution differentiation was also subject to changes in biofilm property settings. Therefore, biofilm properties need to be quantified experimentally or set properly to model N2O production from the MABR correctly. As a good practice for one-dimensional modeling of N2O production from biofilm-based reactors, especially the MABR performing autotrophic deammonification, the essential information about those influential biofilm property settings identified in this study should be disclosed and clearly documented, thus ensuring both the reproducibility of modeling results and the reliable applications of N2O models.}, } @article {pmid34019393, year = {2021}, author = {Zheng, J and Shang, Y and Wu, Y and Wu, J and Chen, J and Wang, Z and Sun, X and Xu, G and Deng, Q and Qu, D and Yu, Z}, title = {Diclazuril Inhibits Biofilm Formation and Hemolysis of Staphylococcus aureus.}, journal = {ACS infectious diseases}, volume = {7}, number = {6}, pages = {1690-1701}, doi = {10.1021/acsinfecdis.1c00030}, pmid = {34019393}, issn = {2373-8227}, mesh = {Biofilms ; Hemolysis ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Nitriles ; *Staphylococcus aureus/genetics ; Triazines ; }, abstract = {Biofilm formation and hemolysis induced by Staphylococcus aureus are closely related to pathogenicity. However, no drugs exist to inhibit biofilm formation or hemolysis induced by S. aureus in clinical practice. This study found diclazuril had antibacterial action against S. aureus with minimum inhibitory concentrations (MICs) at 50 μM for both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). Diclazuril (at 1/4× or 1/8× MICs) significantly inhibited biofilm formation of S. aureus under static or flow-based conditions and also inhibited hemolysis induced by S. aureus. The RNA levels of transcriptional regulatory genes (agrA, agrC, luxS, sarA, sigB, saeR, saeS), biofilm formation-related genes (aur, bap, ccpA, cidA, clfA, clfB, fnbA, fnbB, icaA, icaB, sasG), and virulence-related genes (hla, hlb, hld, hlg, lukDE, lukpvl-S, spa, sbi, alpha-3 PSM, beta PSM, coa) of S. aureus were decreased when treated by diclazuril (at 1/4× MIC) for 4 h. The diclazuril nonsensitive clones of S. aureus were selected in vitro by induction of wildtype strains for about 90 days under the pressure of diclazuril. Mutations in the possible target genes of diclazuril against S. aureus were detected by whole-genome sequencing. This study indicated that there were three amino acid mutations in the diclazuril nonsensitive clone of S. aureus, two of which were located in genes with known function (SMC-Scp complex subunit ScpB and glyceraldehyde-3-phosphate dehydrogenase 1, respectively) and one in a gene with unknown function (hypothetical protein). Diclazuril showed a strong inhibition effect on planktonic cells and biofilm formation of S. aureus with the overexpression of the scpB gene.}, } @article {pmid34018065, year = {2021}, author = {John, G and Schwarz, F and Kravchenko, A and Ommerborn, MA and Becker, J}, title = {Effectivity of homecare and professional biofilm removal procedures on initial supragingival biofilm on laser-microtextured implant surfaces in an ex vivo model.}, journal = {International journal of implant dentistry}, volume = {7}, number = {1}, pages = {51}, pmid = {34018065}, issn = {2198-4034}, mesh = {*Biofilms ; Humans ; Lasers ; Microscopy, Electron, Scanning ; Surface Properties ; *Titanium ; }, abstract = {BACKGROUND: The aim of the current study was the evaluation of initial biofilm adhesion and development on laser-microtextured implant collar surfaces and the examination of effectivity of different biofilm management methods.

METHODS: Initial biofilm formation was investigated on hydrophobic machined and laser-microtextured (Laser-Lok) titanium surfaces and hydrophobic machined and laser-microtextured (Laser-Lok) titanium aluminium vanadium surfaces and compared to hydrophobic smooth pickled titanium surfaces, hydrophilic smooth and acid etched titanium surfaces, hydrophobic sandblasted large grid and acid etched titanium surfaces (titanium Promote) via erythrosine staining and subsequent histomorphometrical analysis and scanning electron microscopic investigations. After decontamination procedures, performed via tooth brushing and glycine powder blasting, clean implant surface was detected via histomorphometrical analysis.

RESULTS: After 24 h mean initial plaque area was detected in the following descending order: smooth pickled titanium > titanium Promote > hydrophilic smooth and acid etched titanium > Laser-Lok titanium > Laser-Lok titanium aluminium vanadium. The same order was determined after 48 h of biofilm formation. After glycine powder blasting all samples depicted almost 100% clean implant surface. After tooth brushing, Laser-Lok titanium (67.19%) and Laser-Lok titanium aluminium vanadium (69.80%) showed significantly more clean implant surface than the other structured surfaces, hydrophilic smooth and acid etched titanium (50.34%) and titanium Promote (33.89%). Smooth pickled titanium showed almost complete clean implant surface (98.84%) after tooth brushing.

CONCLUSIONS: Both Laser-Lok surfaces showed less initial biofilm formation after 24 and 48 h than the other implant surfaces. In combination with the significant higher clean implant surfaces after domestic decontamination procedure via tooth brushing, both Laser-Lok surfaces could be a candidate for modified implant and abutment designs, especially in transmucosal areas.}, } @article {pmid34017053, year = {2021}, author = {Melo, LDR and Ferreira, R and Costa, AR and Oliveira, H and Azeredo, J}, title = {Author Correction: Efficacy and safety assessment of two enterococci phages in an in vitro biofilm wound model.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {11008}, doi = {10.1038/s41598-021-90464-4}, pmid = {34017053}, issn = {2045-2322}, } @article {pmid34015803, year = {2021}, author = {Liu, L and Guo, S and Chen, X and Yang, S and Deng, X and Tu, M and Tao, Y and Xiang, W and Rao, Y}, title = {Metabolic profiles of Lactobacillus paraplantarum in biofilm and planktonic states and investigation of its intestinal modulation and immunoregulation in dogs.}, journal = {Food & function}, volume = {12}, number = {12}, pages = {5317-5332}, doi = {10.1039/d1fo00905b}, pmid = {34015803}, issn = {2042-650X}, mesh = {Animals ; Biofilms/*drug effects ; Dogs ; Gastrointestinal Microbiome/physiology ; Intestines/immunology/*microbiology ; Lactobacillus/*metabolism ; Metabolic Networks and Pathways ; *Metabolome ; Metabolomics ; Probiotics/pharmacology ; }, abstract = {The use of probiotics has recently become a considerably promising research area. The most advanced fourth-generation probiotics involve beneficial bacteria enclosed in biofilms. However, differences in the effects of probiotics in biofilm and those in planktonic states are, as yet, unclear. In this study, it was ascertained that the biofilm mode of Lactobacillus paraplantarum L-ZS9 had a comparatively higher density and stronger resistance. Untargeted metabolomics analysis suggested a significant distinction between planktonic and biofilm cells, with amino acids and carbohydrate metabolism both more active in the biofilm mode. Furthermore, the in vivo experiment showed that the biofilm strain displayed better immunomodulation activity, which could increase the relative abundance of Lactobacillus in the intestinal microbiota of dogs. The relative abundance of intestinal microbiota participating in carbohydrate metabolism was higher in the biofilm probiotic-treated dogs. Correlation analysis between L-ZS9-producing metabolites, dog intestinal microbiome diversity and dog blood immune indexes (sIgA or IgG) revealed the interaction between these three components, which might explain the mechanisms by which biofilm L-ZS9 regulated the intestinal microbiome and immunity activity of the host, through the production of various metabolites. Findings of this study will, thus, enhance understanding of the beneficial effects of biofilm probiotics, as well as provide references for further investigation.}, } @article {pmid34015496, year = {2021}, author = {Keefe, BF and Leestemaker-Palmer, A and Bermudez, LE}, title = {Mycobacterium avium subsp. hominissuis (MAH) Microaggregate induction of host innate immunity is linked to biofilm formation.}, journal = {Microbial pathogenesis}, volume = {157}, number = {}, pages = {104977}, doi = {10.1016/j.micpath.2021.104977}, pmid = {34015496}, issn = {1096-1208}, mesh = {Biofilms ; Humans ; Immunity, Innate ; *Mycobacterium ; *Mycobacterium avium ; }, abstract = {Bacterial aggregation is a strategy employed by many pathogens to establish infection. Mycobacterium avium subsp. hominissuis (MAH) undergoes a phenotypic change, microaggregation, when exposed to the respiratory epithelium. We therefore compared how non-aggregated bacteria, or planktonic, and microaggregated MAH can establish lung infections by evaluating mucosal epithelial cell and phagocytic cell responses. It was determined that human mucosal lung epithelial cells recognition of MAH occurs through toll-like receptors 1 and 2. MAPK 1/3 is phosphorylated at 30 min post infection, and active at the transcriptional level 2 h post infection for both phenotypes. Microaggregate infected BEAS-2B cells up-regulated CCL5, IL-1β, and TNF-α cDNA, while planktonic infected cells only up-regulated IL-1β cDNA at 2 h post infection. Microaggregates are associated with increased uptake by macrophages after 1 h compared to planktonic bacteria (8.83% vs. 5.00%, P < 0.05). In addition, the microaggregate phenotype, when internalized by macrophages, had reduced growth compared to planktonic bacteria, which increased when the host cells were exposed to microaggregate supernatant, obtained from the incubation of MAH with HEp-2 cells. Moreover, microaggregate supernatant stimulated biofilm formation by planktonic and microaggregated bacteria. Microaggregate supernatant also induces the production of both pro- and anti-inflammatory cytokines, which was suppressed following MAH infection. The results suggest that epithelial recognition occurs during MAH infection, and the microaggregate phenotype stimulates an inflammatory response. The initial bacterial interaction with the mucosal epithelium and development of the microaggregate phenotype has a role in pathogenesis, allowing for more robust biofilm formation and infection establishment.}, } @article {pmid34014346, year = {2021}, author = {Fan, Q and Yuan, Y and Jia, H and Zeng, X and Wang, Z and Hu, Z and Gao, Z and Yue, T}, title = {Antimicrobial and anti-biofilm activity of thymoquinone against Shigella flexneri.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {11}, pages = {4709-4718}, pmid = {34014346}, issn = {1432-0614}, support = {2019YFC1606703//National Key Research and Development Project During the 13th Five-Year Plan/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Benzoquinones/pharmacology ; *Biofilms ; Humans ; *Shigella flexneri ; }, abstract = {Shigella flexneri (Sh. flexneri), a common foodborne pathogen, has become one of the main threats to food safety and human health due to its high pathogenicity and persistent infection. The objective of this study was to explore the antimicrobial and anti-biofilm activities and the possible mechanism of thymoquinone (TQ) against Sh. flexneri. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of TQ against Sh. flexneri were 0.4 and 0.5 mg/mL, respectively. TQ showed bactericidal activity against Sh. flexneri in culture medium and milk system. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) observations demonstrated that TQ could induce abnormal cell morphology and destroy cell membrane. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis suggested that TQ could inhibit protein synthesis in Sh. flexneri. Also, at sub-inhibitory concentrations (SICs), TQ exhibited an inhibitory effect on Sh. flexneri biofilm formation, which was confirmed by crystal violet quantitative analysis and SEM observation. Real-time quantitative PCR (RT-qPCR) analyses revealed that TQ downregulated the expression of genes involved in Sh. flexneri biofilm formation. Thus, TQ has potential as a natural antimicrobial and anti-biofilm agent to address the contamination and infection caused by Sh. flexneri. KEY POINTS: • Antimicrobial and anti-biofilm activity of TQ on Shigella flexneri were investigated. • TQ inhibited biofilm formation by Shigella flexneri. • TQ provided a new strategy for Shigella flexneri control.}, } @article {pmid34013421, year = {2021}, author = {Unsal, T and Wang, D and Kumseranee, S and Punpruk, S and Gu, T}, title = {D-Tyrosine enhancement of microbiocide mitigation of carbon steel corrosion by a sulfate reducing bacterium biofilm.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {6}, pages = {103}, pmid = {34013421}, issn = {1573-0972}, support = {TUBITAK-2219//Türkiye Bilimsel ve Teknolojik Araştirma Kurumu/ ; }, mesh = {Biofilms/*drug effects ; Carbon/*chemistry ; Corrosion ; Culture Media/chemistry ; Desulfovibrio vulgaris/drug effects/*physiology ; Dielectric Spectroscopy ; Microbial Sensitivity Tests ; Nitriles/chemistry/*pharmacology ; Oxidation-Reduction ; Steel/chemistry ; Sulfates/metabolism ; Tyrosine/*chemistry ; }, abstract = {Microbiocides are used to control problematic microorganisms. High doses of microbiocides cause environmental and operational problems. Therefore, using microbiocide enhancers to make microbiocides more efficacious is highly desirable. 2,2-dibromo-3-nitrilopropionamide (DBNPA) is a popular biodegradable microbiocide. D-Amino acids have been used in lab tests to enhance microbiocides to treat microbial biofilms. In this investigation, D-tyrosine was used to enhance DBNPA against Desulfovibrio vulgaris biofilm on C1018 carbon steel. After 7 days of incubation, the mass loss of coupons without treatment chemicals in the ATCC 1249 culture medium was found to be 3.1 ± 0.1 mg/cm[2]. With 150 ppm (w/w) DBNPA in the culture medium, the mass loss was reduced to 1.9 ± 0.1 mg/cm[2] accompanied by a 1-log reduction in the sessile cell count. The 150 ppm DBNPA + 1 ppm D-tyrosine combination attained an extra 3-log reduction in sessile cell count and an additional 30% reduction in mass loss compared with 150 ppm DBNPA only treatment. The combination also led to a smaller maximum pit depth. Linear polarization resistance (LPR), electrochemical impedance spectrometry (EIS), and potentiodynamic polarization (PDP) tests corroborated the enhancement effects.}, } @article {pmid34013169, year = {2021}, author = {Guzmán-Soto, I and McTiernan, C and Gonzalez-Gomez, M and Ross, A and Gupta, K and Suuronen, EJ and Mah, TF and Griffith, M and Alarcon, EI}, title = {Mimicking biofilm formation and development: Recent progress in in vitro and in vivo biofilm models.}, journal = {iScience}, volume = {24}, number = {5}, pages = {102443}, pmid = {34013169}, issn = {2589-0042}, abstract = {Biofilm formation in living organisms is associated to tissue and implant infections, and it has also been linked to the contribution of antibiotic resistance. Thus, understanding biofilm development and being able to mimic such processes is vital for the successful development of antibiofilm treatments and therapies. Several decades of research have contributed to building the foundation for developing in vitro and in vivo biofilm models. However, no such thing as an "all fit" in vitro or in vivo biofilm models is currently available. In this review, in addition to presenting an updated overview of biofilm formation, we critically revise recent approaches for the improvement of in vitro and in vivo biofilm models.}, } @article {pmid34009538, year = {2021}, author = {Tang, T and Xu, Y and Wang, J and Tan, X and Zhao, X and Zhou, P and Kong, F and Zhu, C and Lu, C and Lin, H}, title = {Evaluation of the differences between biofilm and planktonic Brucella abortus via metabolomics and proteomics.}, journal = {Functional & integrative genomics}, volume = {21}, number = {3-4}, pages = {421-433}, pmid = {34009538}, issn = {1438-7948}, support = {31702278//National Natural Science Foundation of China/ ; KYDS201801, KJQN201826//the Fundamental Research Funds for the Central Universities/ ; 2019HK018//the Science Foundation of General Administration of Customs of the People's Republic China/ ; 2008IK004//the Science Foundation of General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic China/ ; }, mesh = {ATP-Binding Cassette Transporters ; *Biofilms ; *Brucella abortus/genetics/metabolism ; Fatty Acids ; *Metabolomics ; *Plankton/microbiology ; *Proteomics ; }, abstract = {This study analyzed the difference between biofilm and planktonic Brucella abortus using metabolomics and proteomics. Brucella abortus was cultured in different media to induce Brucella abortus biofilm formation and planktonic cells, followed by metabolomics and proteomics analyses for these two samples. Significant differential metabolites were identified, followed by KEGG pathway analysis. Differentially expressed proteins were identified, followed by subcellular localization, GO annotation, and KEGG pathway enrichment. Additionally, a correlation analysis of metabolomics and proteomics was performed. Metabolomics analysis showed 7682 positive and 4433 negative metabolites, including 188 positive and 117 negative significant differential metabolites. These differential metabolites were enriched in fatty acid/unsaturated fatty acid biosynthesis and linoleic acid metabolism. Proteomics analysis revealed 1759 proteins, including 486 differentially expressed proteins, which were enriched in various metabolic and degradation-related pathways. Subcellular localization showed that 74.3% of the differential proteins were cytoplasmic proteins. Correlation analysis showed that 1-palmitoyl-2-oleoyl-phosphatidylglycerol had the most significant correlations with proteins, followed by cytosine. Both metabolites correlated with the protein Q57EI7 (RbsB-1, ribose ABC transporter). One common pathway, fatty acid biosynthesis, was identified by both proteomics and metabolomics analyses that involved the metabolites, oleic acid, and protein Q57DK3 (biotin carboxylase). There were metabolomic and proteomic differences between Brucella abortus biofilm and planktonic cells, and these results provide novel insights into the biofilm-forming process of Brucella abortus.}, } @article {pmid34006656, year = {2021}, author = {Kim, HE and Dhall, A and Liu, Y and Bawazir, M and Koo, H and Hwang, G}, title = {Intervening in Symbiotic Cross-Kingdom Biofilm Interactions: a Binding Mechanism-Based Nonmicrobicidal Approach.}, journal = {mBio}, volume = {12}, number = {3}, pages = {}, pmid = {34006656}, issn = {2150-7511}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE027970/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*metabolism ; Dental Caries/microbiology ; Gingiva/cytology ; Humans ; Keratinocytes/microbiology ; Mannans/metabolism ; Microscopy, Atomic Force ; Streptococcus mutans/*metabolism ; *Symbiosis ; }, abstract = {Early childhood caries is a severe oral disease that results in aggressive tooth decay. Particularly, a synergistic association between a fungus, Candida albicans, and a cariogenic bacterium, Streptococcus mutans, promotes the development of hard-to-remove and highly acidic biofilms, exacerbating the virulent damage. These interactions are largely mediated via glucosyltransferases (GtfB) binding to mannans on the cell wall of C. albicans Here, we present an enzymatic approach to target GtfB-mannan interactions in this cross-kingdom consortium using mannan-degrading exo- and endo-enzymes. These exo- and endo-enzymes are highly effective in reducing biofilm biomass without killing microorganisms, as well as alleviating the production of an acidic pH environment conducive to tooth decay. To corroborate these results, we present biophysical evidence using single-molecule atomic force microscopy, biofilm shearing, and enamel surface topography analyses. Data show a drastic decrease in binding forces of GtfB to C. albicans (∼15-fold reduction) following enzyme treatment. Furthermore, enzymatic activity disrupted biofilm mechanical stability and significantly reduced human tooth enamel demineralization without cytotoxic effects on gingival keratinocytes. Our results represent significant progress toward a novel nonbiocidal therapeutic intervention against pathogenic bacterial-fungal biofilms by targeting the interkingdom receptor-ligand binding interactions.IMPORTANCE Biofilm formation is a key virulence factor responsible for various infectious diseases. Particularly, interactions between a fungus, Candida albicans, and a bacterium, Streptococcus mutans, have been known to play important roles in the pathogenesis of dental caries. Although some antimicrobials have been applied to treat fungal-involved biofilm-associated diseases, these often lack targeting polymicrobial interactions. Furthermore, these may not be appropriate for preventive measures because these antimicrobials may disrupt ecological microbiota and/or induce the prevalence of drug resistance over time. By specifically targeting the interaction mechanism whereby mannoproteins on the C. albicans surface mediate the cross-kingdom interaction, we demonstrated that mannoprotein-degrading enzymes can effectively disrupt biofilm interactions without microbiocidal effects or causing cytotoxicity to human cells. This suggests a potential application as a targeted approach for intervening a pathogenic cross-kingdom biofilm associated with a costly and unresolved oral disease.}, } @article {pmid34005832, year = {2021}, author = {Salem, HS and Mont, MA}, title = {A Novel Biofilm-Disrupting Wound Care Technology for the Prevention of Surgical Site Infections Following Total Joint Arthroplasty: A Conceptual Review.}, journal = {Surgical technology international}, volume = {38}, number = {}, pages = {361-370}, doi = {10.52198/21.STI.38.OS1447}, pmid = {34005832}, issn = {1090-3941}, mesh = {Anti-Bacterial Agents/therapeutic use ; Arthroplasty ; Biofilms ; *Extracellular Polymeric Substance Matrix ; Humans ; *Surgical Wound Infection/prevention & control ; Technology ; }, abstract = {Surgical site infections (SSIs) are a major driver for increased costs following lower extremity joint arthroplasty procedures. It has been estimated that these account for over $2 billion in annual costs in the United States. While many of the current strategies for the prevention and treatment of SSIs target planktonic bacteria, 80 to 90% of bacterial pathogens exist in a sessile state. These sessile bacteria can produce extracellular polymeric substance (EPS) as protective barriers from host immune defenses and antimicrobial agents and thus, can be exceedingly difficult to eradicate. A novel wound care gel that disrupts the EPS and destroys the inciting pathogens has been developed for the treatment and prevention of biofilm-related infections. This is achieved by the simultaneous action of four key ingredients: (1) citric acid; (2) sodium citrate; (3) benzalkonium chloride; and (4) polyethylene glycol. Together, these constituents create a high osmolarity, pH-controlled environment that deconstructs and prevents biofilm formation, while destroying pathogens and promoting a moist environment for optimal wound healing. The available clinical evidence demonstrating the efficacy of this technology has been summarized, as well as the economic implications of its implementation and the authors' preferred method of its use. Due to the multifaceted burden associated with biofilm-producing bacteria in arthroplasty patients, this technology may prove to be beneficial for patients who have higher risks for infection, or perhaps, as a prophylactic measure to prevent infections for all patients.}, } @article {pmid34004532, year = {2021}, author = {Dan, NH and Le Luu, T}, title = {High organic removal of landfill leachate using a continuous flow sequencing batch biofilm reactor (CF-SBBR) with different biocarriers.}, journal = {The Science of the total environment}, volume = {787}, number = {}, pages = {147680}, doi = {10.1016/j.scitotenv.2021.147680}, pmid = {34004532}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Nitrogen ; Waste Disposal, Fluid ; *Water Pollutants, Chemical ; }, abstract = {Landfill leachate contains many pollutants that have a negative effect on the environment when improperly discharged. Thus the treatment of landfill leachate is a crucial issue, especially in the bigger cities in developing countries. In this study, landfill leachate is treated using a continuous flow sequencing biofilm batch reactor (CF-SBBR) with different biocarriers (non-carrier (NC), kaldness [K1] (K1), mutag biochip 30™ (MB), and sponge polyurethane (SP)). The results show that the best COD, TOC, and NH4[+]-N removal efficiencies were 79.6 ± 0.8%, 78.1 ± 1.9% and 77.5 ± 3.9% in the MB biocarriers tank with an aeration/mixing ratio of 1.3, a cycle time of 9 h and an organic loading rate (OLR) of 1.74 kgCOD/m[3].d. The TN removal efficiencies was decreased when there was an increase in the biocarrier's surface area (NC > K1 > MB > SP). At the highest it was 46.1 ± 6.4%, where the aeration/mixing ratio was 1.3, the cycle time was 9 h, and the OLR was 1.52 kgCOD/m[3].d. The higher the surface area of the biocarriers, the greater the anti-shock organic loading capacity of the biocarriers due to the formation of biofilm layers. The microbial communities in the CF-SBBR tanks were abundant with common phylum bacteria as in a conventional activated sludge system. Anammox candidatus bacteria was found to total 0.5%. This study concluded that CF-SBBR is an efficient method to treat landfill leachate.}, } @article {pmid34003887, year = {2021}, author = {}, title = {Erratum in: Sol-Gel Nanocomposite Coatings for Preventing Biofilm Formation on Contact Lens Cases.}, journal = {Translational vision science & technology}, volume = {10}, number = {2}, pages = {2}, doi = {10.1167/tvst.10.2.2}, pmid = {34003887}, issn = {2164-2591}, } @article {pmid34001238, year = {2021}, author = {Wang, Z and Zhou, Y and Han, Q and Ye, X and Chen, Y and Sun, Y and Liu, Y and Zou, J and Qi, G and Zhou, X and Cheng, L and Ren, B}, title = {Synonymous point mutation of gtfB gene caused by therapeutic X-rays exposure reduced the biofilm formation and cariogenic abilities of Streptococcus mutans.}, journal = {Cell & bioscience}, volume = {11}, number = {1}, pages = {91}, pmid = {34001238}, issn = {2045-3701}, support = {81430011//National Natural Science Foundation of China/ ; 81870759//National Natural Science Foundation of China/ ; 81870778//National Natural Science Foundation of China/ ; 2020YJ0227//Applied Basic Research Programs of Sichuan Province/ ; 2017JQ0028//the Youth Grant of the Science and Technology Department of Sichuan Province/ ; }, abstract = {BACKGROUND: The shift of oral microbiota is a critical factor of radiation caries in head and neck cancer patients after the radiotherapy. However, the direct effects of irradiation on the genome and virulence of cariogenic bacteria are poorly described. Here we investigated the genomic mutations and virulence change of Streptococcus mutans (S. mutans), the major cariogenic bacteria, exposed to the therapeutic doses of X-rays.

RESULTS: X-ray reduced the survival fraction of S. mutans and impacted its biofilm formation. We isolated a biofilm formation-deficient mutant #858 whose genome only possessed three synonymous mutations (c.2043 T > C, c.2100C > T, c.2109A > G) in gtfB gene. The "silent mutation" of c.2043 T > C in gtfB gene can cause the down-regulation of all of the gtfs genes' expression and decrease the GtfB enzyme secretion without the effect on the growth due to the codon bias. #858 and synonymous point mutation strain gtfB [2043 T>C], similar to the gtfB gene null mutant Δ gtfB, can significantly decrease the extracellular polysaccharide production, biofilm formation and cariogenic capabilities both in vitro and in vivo compared with wild type.

CONCLUSION: The direct exposure of X-ray radiation can affect the genome and virulence of oral bacteria even at therapeutic doses. The synonymous mutations of genome are negligent factors for gene expression and related protein translation due to the codon usage frequency.}, } @article {pmid34000535, year = {2021}, author = {Maurya, AK and Reddy, BS and Theerthagiri, J and Narayana, PL and Park, CH and Hong, JK and Yeom, JT and Cho, KK and Reddy, NS}, title = {Modeling and optimization of process parameters of biofilm reactor for wastewater treatment.}, journal = {The Science of the total environment}, volume = {787}, number = {}, pages = {147624}, doi = {10.1016/j.scitotenv.2021.147624}, pmid = {34000535}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; *Metals, Heavy ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {The efficiency of heavy metal in biofilm reactors depends on absorption process parameters, and those relationships are complicated. This study explores artificial neural networks (ANNs) feasibility to correlate the biofilm reactor process parameters with absorption efficiency. The heavy metal removal and turbidity were modeled as a function of five process parameters, namely pH, temperature(°C), feed flux(ml/min), substrate flow(ml/min), and hydraulic retention time(h). We developed a standalone ANN software for predicting and analyzing the absorption process in handling industrial wastewater. The model was tested extensively to confirm that the predictions are reasonable in the context of the absorption kinetics principles. The model predictions showed that the temperature and pH values are the most influential parameters affecting absorption efficiency and turbidity.}, } @article {pmid33997991, year = {2021}, author = {Svarcova, V and Zdenkova, K and Sulakova, M and Demnerova, K and Pazlarova, J}, title = {Contribution to determination of extracellular DNA origin in the biofilm matrix.}, journal = {Journal of basic microbiology}, volume = {61}, number = {7}, pages = {652-661}, doi = {10.1002/jobm.202100090}, pmid = {33997991}, issn = {1521-4028}, support = {MSMT No 21-SVV/2018//Ministerstvo Školství, Mládeže a Telovýchovy/ ; 17-15936S//Grantová Agentura Ceské Republiky/ ; }, mesh = {DNA, Bacterial/*genetics ; Extracellular Matrix/*genetics/*metabolism ; Extracellular Polymeric Substance Matrix/*genetics ; Listeria monocytogenes/genetics ; Salmonella enterica/genetics ; Staphylococcus aureus/genetics ; }, abstract = {This study is focused on the analysis of extracellular DNA (eDNA) from a biofilm matrix formed by Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica. The presence of eDNA in the biofilm of all the studied strains was confirmed by confocal laser scanning microscopy using fluorescent dyes with high affinity to nucleic acid. The protocol for eDNA isolation from the biofilm matrix was established, and subsequent characterization of the eDNA was performed. The purified eDNA obtained from the biofilm matrix of all three microorganisms was compared to the genomic DNA (gDNA) isolated from relevant planktonic grown cells. The process of eDNA isolation consisted of biofilm cultivation, its collection, sonication, membrane filtration, dialysis, lyophilisation, and extraction of DNA separated from the biofilm matrix with cetyltrimethylammonium bromide. An amplified fragment length polymorphism (AFLP) was used for comparing eDNA and gDNA. AFLP profiles showed a significant similarity between eDNA and gDNA at the strain level. The highest similarity, with a profile concordance rate of 94.7% per strain, was observed for S. aureus, L. monocytogenes, and S. enterica exhibited lower profiles similarity (78% and 60%, respectively). The obtained results support the hypothesis that the eDNA of studied bacterial species has its origin in the gDNA.}, } @article {pmid33997876, year = {2021}, author = {Zhang, T and Kalimuthu, S and Rajasekar, V and Xu, F and Yiu, YC and Hui, TKC and Neelakantan, P and Chu, Z}, title = {Biofilm inhibition in oral pathogens by nanodiamonds.}, journal = {Biomaterials science}, volume = {9}, number = {15}, pages = {5127-5135}, doi = {10.1039/d1bm00608h}, pmid = {33997876}, issn = {2047-4849}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Microbial Sensitivity Tests ; Mouth ; *Nanodiamonds ; }, abstract = {Complex microbial communities, e.g., biofilms residing in our oral cavity, have recognized clinical significance, as they are typically the main cause for infections. Particularly, they show high resistance to conventional antibiotics, and alternatives including nanotechnology are being intensively explored nowadays to provide more efficient therapeutics. Diamond nanoparticles, namely, nanodiamonds (NDs) with many promising physico-chemical properties, have been demonstrated to work as an effective antibacterial agent against planktonic cells (free-floating state). However, little is known about the behaviors of NDs against biofilms (sessile state). In this study, we uncovered their role in inhibiting biofilm formation and their disrupting effect on preformed biofilms in several selected orally and systemically important organisms. The current findings will advance the mechanistic understanding of NDs on oral pathogens and might accelerate corresponding clinical translation.}, } @article {pmid33996634, year = {2021}, author = {Lopes, LG and Csonka, LA and Castellane, JAS and Oliveira, AW and de Almeida-Júnior, S and Furtado, RA and Tararam, C and Levy, LO and Crivellenti, LZ and Moretti, ML and Giannini, MJSM and Pires, RH}, title = {Disinfectants in a Hemodialysis Setting: Antifungal Activity Against Aspergillus and Fusarium Planktonic and Biofilm Cells and the Effect of Commercial Peracetic Acid Residual in Mice.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {663741}, pmid = {33996634}, issn = {2235-2988}, mesh = {Animals ; Antifungal Agents ; Aspergillus ; Biofilms ; *Disinfectants ; *Fusarium ; Humans ; Mice ; Microbial Sensitivity Tests ; Peracetic Acid ; Plankton ; Renal Dialysis ; }, abstract = {Aspergillus and Fusarium cause a broad spectrum of infections in humans, mainly in immunocompromised patients. Among these, patients undergoing hemodialysis are highly susceptible to infections, requiring a constant and adequate environmental disinfection program. Nevertheless, monitoring the residual disinfectants can contribute to the morbidity and mortality reduction in these patients. Here, we evaluated the susceptibility of Aspergillus spp. (n=19) and Fusarium spp. (n=13) environmental isolates against disinfectants (acetic acid, citric acid, peracetic acid, sodium hypochlorite, and sodium metabisulphite) at different concentrations and time exposures. Also, we investigated the in vivo toxicity of the peracetic acid residual concentration in mice. Fusarium isolates were identified by F. equiseti, F. oxysporum and F. solani while Aspergillus presented clinically relevant species (A. fumigatus, A. niger and A. terreus) and environmental ones. Against planktonic cells, only two disinfectants (acetic acid and sodium hypochlorite) showed a fungicidal effect on Fusarium spp., while only one (sodium hypochlorite) was effective against Aspergillus spp. Both fungi formed robust in vitro biofilms with large amounts of the extracellular matrix, as evidenced by electron micrographs. Exposure of fungal biofilms to disinfectants showed sensitivity to three (acetic, citric, and peracetic acids), although the concentrations and times of exposure varied according to the fungal genus. Mice exposure to the residual dose of peracetic acid during 60 weeks showed anatomopathological, hematological, and biochemical changes. The implementation of news control measures and those that already exist can help reduce infections, the second cause of death and morbidity in these patients, besides providing safety and well-being to them, a priority of any quality health program.}, } @article {pmid33996521, year = {2021}, author = {Goel, N and Fatima, SW and Kumar, S and Sinha, R and Khare, SK}, title = {Antimicrobial resistance in biofilms: Exploring marine actinobacteria as a potential source of antibiotics and biofilm inhibitors.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {30}, number = {}, pages = {e00613}, pmid = {33996521}, issn = {2215-017X}, abstract = {Antimicrobial resistance (AMR) is one of the serious global public health threats that require immediate action. With the emergence of new resistance mechanisms in infection-causing microorganisms such as bacteria, fungi, and viruses, AMR threatens the effective prevention and treatment of diseases caused by them. This has resulted in prolonged illness, disability, and death. It has been predicted that AMR will lead to over ten million deaths by 2050. The rapid spread of multidrug-resistant bacteria is also causing old antibiotics to become ineffective. Among the diverse factors contributing to AMR, intrinsic biofilm development has been highlighted as an essential contributing facet. Moreover, biofilm-derived antibiotic tolerance leads to serious recurrent chronic infections. Therefore, the discovery of novel bioactive molecules is a potential solution that can help combat AMR. To achieve this, sustained mining of novel antimicrobial leads from actinobacteria, particularly marine actinobacteria, can be a promising strategy. Given their vast diversity and different habitats, the extraordinary capacity of actinobacteria can be tapped to synthesize new antibiotics or bioactive molecules for biofilm inhibition. Advanced screening strategies and novel approaches in the field of modern biochemical and molecular biology can be used to detect such new compounds. In view of this, the present review focuses on understanding some of the recent strategies to inhibit biofilm formation and explores the potential role of marine actinobacteria as sources of novel antibiotics and biofilm inhibitor molecules.}, } @article {pmid33995317, year = {2021}, author = {Knott, S and Curry, D and Zhao, N and Metgud, P and Dastgheyb, SS and Purtill, C and Harwood, M and Chen, AF and Schaer, TP and Otto, M and Hickok, NJ}, title = {Staphylococcus aureus Floating Biofilm Formation and Phenotype in Synovial Fluid Depends on Albumin, Fibrinogen, and Hyaluronic Acid.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {655873}, pmid = {33995317}, issn = {1664-302X}, support = {R01 AR069119/AR/NIAMS NIH HHS/United States ; R01 AR072513/AR/NIAMS NIH HHS/United States ; R01 AR076941/AR/NIAMS NIH HHS/United States ; }, abstract = {Biofilms are typically studied in bacterial media that allow the study of important properties such as bacterial growth. However, the results obtained in such media cannot take into account the bacterial localization/clustering caused by bacteria-protein interactions in vivo and the accompanying alterations in phenotype, virulence factor production, and ultimately antibiotic tolerance. We and others have reported that methicillin-resistant or methicillin-susceptible Staphylococcus aureus (MRSA or MSSA, respectively) and other pathogens assemble a proteinaceous matrix in synovial fluid. This proteinaceous bacterial aggregate is coated by a polysaccharide matrix as is characteristic of biofilms. In this study, we identify proteins important for this aggregation and determine the concentration ranges of these proteins that can reproduce bacterial aggregation. We then test this protein combination for its ability to cause marked aggregation, antibacterial tolerance, preservation of morphology, and expression of the phenol-soluble modulin (PSM) virulence factors. In the process, we create a viscous fluid that models bacterial behavior in synovial fluid. We suggest that our findings and, by extension, use of this fluid can help to better model bacterial behavior of new antimicrobial therapies, as well as serve as a starting point to study host protein-bacteria interactions characteristic of physiological fluids.}, } @article {pmid33995316, year = {2021}, author = {Deng, K and Jiang, W and Jiang, Y and Deng, Q and Cao, J and Yang, W and Zhao, X}, title = {ALS3 Expression as an Indicator for Candida albicans Biofilm Formation and Drug Resistance.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {655242}, pmid = {33995316}, issn = {1664-302X}, abstract = {Resistance caused by the formation of the Candida albicans (C. albicans) biofilm is one of the main reasons for antifungal therapy failure. Thus, it is important to find indicators that predict C. albicans biofilm formation to provide evidence for the early prevention and treatment of the C. albicans biofilms. In this study, C. albicans samples were selected from C. albicans septicemia that were sensitive to common antifungal agents. It was found that the agglutinin-like sequence 3 (ALS3) gene was differentially expressed in free, antifungal, drug-sensitive C. albicans. The average ALS3 gene expression was higher in the C. albicans strains with biofilm formation than that in the C. albicans strains without biofilm formation. Then, it was further confirmed that the rate of biofilm formation was higher in the high ALS3 gene expression group than that in the low ALS3 gene expression group. It was found that C. albicans with biofilm formation was more resistant to fluconazole, voriconazole, and itraconazole. However, it maintained its sensitivity to caspofungin and micafungin in vitro and in mice. Further experiments regarding the prevention of C. albicans biofilm formation were performed in mice, in which only caspofungin and micafungin prevented C. albicans biofilm formation. These results suggest that the expression level of ALS3 in C. albicans may be used as an indicator to determine whether C. albicans will form biofilms. The results also show that the biofilm formation of C. albicans remained sensitive to caspofungin and micafungin, which may help to guide the selection of clinical antifungal agents for prevention and therapy.}, } @article {pmid33995311, year = {2021}, author = {Handorf, O and Pauker, VI and Weihe, T and Schäfer, J and Freund, E and Schnabel, U and Bekeschus, S and Riedel, K and Ehlbeck, J}, title = {Plasma-Treated Water Affects Listeria monocytogenes Vitality and Biofilm Structure.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {652481}, pmid = {33995311}, issn = {1664-302X}, abstract = {Background: Plasma-generated compounds (PGCs) such as plasma-processed air (PPA) or plasma-treated water (PTW) offer an increasingly important alternative for the control of microorganisms in hard-to-reach areas found in several industrial applications including the food industry. To this end, we studied the antimicrobial capacity of PTW on the vitality and biofilm formation of Listeria monocytogenes, a common foodborne pathogen. Results: Using a microwave plasma (MidiPLexc), 10 ml of deionized water was treated for 100, 300, and 900 s (pre-treatment time), after which the bacterial biofilm was exposed to the PTW for 1, 3, and 5 min (post-treatment time) for each pre-treatment time, separately. Colony-forming units (CFU) were significantly reduced by 4.7 log10 ± 0.29 log10, as well as the metabolic activity decreased by 47.9 ± 9.47% and the cell vitality by 69.5 ± 2.1%, compared to the control biofilms. LIVE/DEAD staining and fluorescence microscopy showed a positive correlation between treatment and incubation times, as well as reduction in vitality. Atomic force microscopy (AFM) indicated changes in the structure quality of the bacterial biofilm. Conclusion: These results indicate a promising antimicrobial impact of plasma-treated water on Listeria monocytogenes, which may lead to more targeted applications of plasma decontamination in the food industry in the future.}, } @article {pmid33995297, year = {2021}, author = {Atriwal, T and Azeem, K and Husain, FM and Hussain, A and Khan, MN and Alajmi, MF and Abid, M}, title = {Mechanistic Understanding of Candida albicans Biofilm Formation and Approaches for Its Inhibition.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {638609}, pmid = {33995297}, issn = {1664-302X}, abstract = {In recent years, the demand for novel antifungal therapies has increased several- folds due to its potential to treat severe biofilm-associated infections. Biofilms are made by the sessile microorganisms attached to the abiotic or biotic surfaces, enclosed in a matrix of exopolymeric substances. This results in new phenotypic characteristics and intrinsic resistance from both host immune response and antimicrobial drugs. Candida albicans biofilm is a complex association of hyphal cells that are associated with both abiotic and animal tissues. It is an invasive fungal infection and acts as an important virulent factor. The challenges linked with biofilm-associated diseases have urged scientists to uncover the factors responsible for the formation and maturation of biofilm. Several strategies have been developed that could be adopted to eradicate biofilm-associated infections. This article presents an overview of the role of C. albicans biofilm in its pathogenicity, challenges it poses and threats associated with its formation. Further, it discusses strategies that are currently available or under development targeting prostaglandins, quorum-sensing, changing surface properties of biomedical devices, natural scaffolds, and small molecule-based chemical approaches to combat the threat of C. albicans biofilm. This review also highlights the recent developments in finding ways to increase the penetration of drugs into the extracellular matrix of biofilm using different nanomaterials against C. albicans.}, } @article {pmid33994861, year = {2021}, author = {Li, Y and Li, X and Hao, Y and Liu, Y and Dong, Z and Li, K}, title = {Biological and Physiochemical Methods of Biofilm Adhesion Resistance Control of Medical-Context Surface.}, journal = {International journal of biological sciences}, volume = {17}, number = {7}, pages = {1769-1781}, pmid = {33994861}, issn = {1449-2288}, mesh = {Bacteria/genetics/*growth & development ; Bacterial Adhesion/*genetics ; Bacterial Proteins/*genetics ; *Biofilms ; Humans ; Quorum Sensing/*genetics ; }, abstract = {The formation of biofilms on medical-context surfaces gives the EPS embedded bacterial community protection and additional advantages that planktonic cells would not have such as increased antibiotic resistance and horizontal gene transfer. Bacterial cells tend to attach to a conditioning layer after overcoming possible electrical barriers and go through two phases of attachments: reversible and irreversible. In the first, bacterial attachment to the surface is reversible and occurs quickly whilst the latter is permanent and takes place over a longer period of time. Upon reaching a certain density in the bacterial community, quorum sensing causes phenotypical changes leading to a loss in motility and the production of EPS. This position paper seeks to address the problem of bacterial adhesion and biofilm formation for the medical surfaces by comparing inhabiting physicochemical interactions and biological mechanisms. Several physiochemical methodologies (e.g. ultrasonication, alternating magnetic field and chemical surface coating) and utilizing biological mechanisms (e.g. quorum quenching and EPS degrading enzymes) were suggested. The possible strategical applications of each category were suggested and evaluated to a balanced position to possibly eliminate the adhesion and formation of biofilms on medical-context surfaces.}, } @article {pmid33994426, year = {2021}, author = {Okamoto-Shibayama, K and Warita, T and Kokubu, E and Kita, D and Kikuchi, Y and Ishihara, K}, title = {Role of Hyalin-like Protein in Gliding and Biofilm Formation by Capnocytophaga Ochracea.}, journal = {The Bulletin of Tokyo Dental College}, volume = {62}, number = {2}, pages = {89-98}, doi = {10.2209/tdcpublication.2020-0051}, pmid = {33994426}, issn = {0040-8891}, mesh = {Bacterial Proteins/genetics ; Bacteroidetes/genetics ; Biofilms ; *Capnocytophaga/genetics ; *Hyalin ; }, abstract = {Capnocytophaga ochracea possesses a type-IX secretion system that exports proteins which have a gliding motility-associated C-terminal (CTD) domain. This system is found in several species of the Bacteroidetes phylum. Hyalin, a large protein encoded by Coch_0033 in C. ochracea ATCC 27872, has a CTD domain and is posited to be involved in quorum sensing according to the database of the Kyoto Encyclopedia of Genes and Genomes. This suggests that it plays a role in biofilm formation via interbacterial communication. The aim of this study was to investigate the potential role of the hyalin-like protein coded by the Coch_0033 gene in gliding and biofilm formation of C. ochracea. A hyalin-like protein-deficient mutant strain of C. ochracea, designated mutant WR-1, was constructed through insertion of the ermF-ermAM cassette into the target gene. The spreading feature at the edge of the colony was lost in the mutant strain. Crystal violet and confocal laser scanning microscopy revealed no difference between the quantity of biofilm organized by the mutant and that organized by the wild-type strain. These data suggest that the hyalin-like protein encoded by the Coch_0033 gene is indeed involved in C. ochracea gliding activity.}, } @article {pmid33992467, year = {2022}, author = {de Azevedo, MN and Marques, NT and Fonseca, MFL and Schuch, LF and de Arruda, JAA and Santos, VR and Mesquita, RA and Moreno, A}, title = {Disinfectant effects of Brazilian green propolis alcohol solutions on the Staphylococcus aureus biofilm of maxillofacial prosthesis polymers.}, journal = {The Journal of prosthetic dentistry}, volume = {128}, number = {6}, pages = {1405-1411}, doi = {10.1016/j.prosdent.2021.03.025}, pmid = {33992467}, issn = {1097-6841}, mesh = {Acrylic Resins/pharmacology ; Biofilms ; *Disinfectants/pharmacology ; *Maxillofacial Prosthesis ; Polymers ; *Propolis/pharmacology ; Staphylococcus aureus/drug effects ; }, abstract = {STATEMENT OF PROBLEM: Brazilian green propolis may be an alternative product that reduces the development of a microbial biofilm on the polymers used for maxillofacial prostheses. However, its effects as a disinfectant have not been fully established.

PURPOSE: The purpose of this in vitro study was to investigate the effects of Brazilian green propolis alcohol solutions against the Staphylococcus aureus biofilm on polymers used in maxillofacial prostheses, the maxillofacial silicone elastomer (MDX4-4210), and specific acrylic resins for ocular prostheses.

MATERIAL AND METHODS: A total of 324 disk-shaped specimens (3×10 mm) of each material were fabricated. All specimens were contaminated with S. aureus (10[8] cells/mL) to assess the antibiofilm activity of immersion solutions and protocols. Thus, 162 specimens of each material were randomly distributed and equally divided into 5 groups of disinfectants and 1 control group: 3 separate groups of 2.5%, 5%, and 10% propolis alcohol solutions, 1 group of 5% propolis alcohol gel, a positive control group of 2% chlorhexidine gluconate, and a negative control group of distilled water. Specimens (n=9) were disinfected by immersion for 5, 10, and 15 minutes and immersed in culture medium for 24 hours. Any notable turgescence in the final medium was considered indicative of a biofilm. The effects of disinfectants were analyzed by a turbidity assay and by scanning electron microscopy. Data were analyzed descriptively.

RESULTS: The final medium with specimens disinfected with 10% propolis alcohol solution showed no turbidity, indicating constant efficacy against the S. aureus biofilm. Similarly, these findings were observed in the 2% chlorhexidine gluconate group. Scanning electron microscopy images demonstrated that the surface of the polymers treated with 10% propolis alcohol solution did not show bacterial colonies.

CONCLUSIONS: Disinfection with 10% green propolis alcohol solution was effective in eliminating the S. aureus biofilm from specimens of maxillofacial elastomer and N1 acrylic resin specific to ocular prostheses by immersion for 5 minutes.}, } @article {pmid33992002, year = {2021}, author = {Liu, G and Li, H and Liu, Y and Jin, R and Zhou, J and Ren, Z and Wang, Z and Yan, C}, title = {Extracellular electron transfer influences the transport and retention of ferrihydrite nanoparticles in quartz sand coated with Shewanella oneidensis biofilm.}, journal = {Journal of hazardous materials}, volume = {417}, number = {}, pages = {126023}, doi = {10.1016/j.jhazmat.2021.126023}, pmid = {33992002}, issn = {1873-3336}, mesh = {Biofilms ; Electron Transport ; Electrons ; Ferric Compounds ; *Nanoparticles ; Quartz ; Sand ; *Shewanella ; }, abstract = {Microbial biofilm has been found to impact the mobility of nanoparticles in saturated porous media by altering physicochemical properties of collector surface. However, little is known about the influence of biofilm's biological activity on nanoparticle transport and retention. Here, the transport of ferrihydrite nanoparticles (FhNPs) was studied in quartz sands coated with biofilm of Shewanella oneidensis MR-1 that is capable of reducing Fe(III) through extracellular electron transfer (EET). It was found that MR-1 biofilm coating enhanced FhNPs' deposition under different pH/ionic strength conditions and humic acid concentrations. More importantly, when the influent electron donor (glucose) concentration was increased to promote biofilm's EET activity, the breakthrough of FhNPs in biofilm-coated sands was inhibited. A lack of continuous and stable supply of electron donor, on the contrary, led to remobilization and release of the originally retained FhNPs. Column experiments with biofilm of EET-deficient MR-1 mutants (ΔomcA/ΔmtrC and ΔcymA) further indicated that the impairment of EET activity decreased the retention of FhNPs. It is proposed that the effective surface binding and adhesion of FhNPs that is required by direct EET cannot be neglected when evaluating the transport of FhNPs in sands coated with electroactive biofilm.}, } @article {pmid33990612, year = {2021}, author = {Mountcastle, SE and Vyas, N and Villapun, VM and Cox, SC and Jabbari, S and Sammons, RL and Shelton, RM and Walmsley, AD and Kuehne, SA}, title = {Biofilm viability checker: An open-source tool for automated biofilm viability analysis from confocal microscopy images.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {44}, pmid = {33990612}, issn = {2055-5008}, mesh = {Bacteria/growth & development ; Bacterial Physiological Phenomena ; *Biofilms/growth & development ; Humans ; Image Processing, Computer-Assisted/*methods ; *Microscopy, Confocal/methods ; *Phenotype ; ROC Curve ; *Software ; }, abstract = {Quantifying biofilm formation on surfaces is challenging because traditional microbiological methods, such as total colony-forming units (CFUs), often rely on manual counting. These are laborious, resource intensive techniques, more susceptible to human error. Confocal laser scanning microscopy (CLSM) is a high-resolution technique that allows 3D visualisation of biofilm architecture. In combination with a live/dead stain, it can be used to quantify biofilm viability on both transparent and opaque surfaces. However, there is little consensus on the appropriate methodology to apply in confocal micrograph processing. In this study, we report the development of an image analysis approach to repeatably quantify biofilm viability and surface coverage. We also demonstrate its use for a range of bacterial species and translational applications. This protocol has been created with ease of use and accessibility in mind, to enable researchers who do not specialise in computational techniques to be confident in applying these methods to analyse biofilm micrographs. Furthermore, the simplicity of the method enables the user to adapt it for their bespoke needs. Validation experiments demonstrate the automated analysis is robust and accurate across a range of bacterial species and an improvement on traditional microbiological analysis. Furthermore, application to translational case studies show the automated method is a reliable measurement of biomass and cell viability. This approach will ensure image analysis is an accessible option for those in the microbiology and biomaterials field, improve current detection approaches and ultimately support the development of novel strategies for preventing biofilm formation by ensuring comparability across studies.}, } @article {pmid33987549, year = {2021}, author = {Karaca, B and Buzrul, S and Cihan, AC}, title = {Mathematical Models for the Biofilm Formation of Geobacillus and Anoxybacillus on Stainless Steel Surface in Whole Milk.}, journal = {Food science of animal resources}, volume = {41}, number = {2}, pages = {288-299}, pmid = {33987549}, issn = {2636-0780}, abstract = {Biofilm formation of Geobacillus thermodenitrificans, Geobacillus thermoglucosidans and Anoxybacillus flavithermus in milk on stainless steel were monitored at 55°C, 60°C, and 65°C for various incubation times. Although species of Geobacillus showed a rapid response and produced biofilm within 4 h on stainless steel, a delay (lag time) was observed for Anoxybacillus. A hyperbolic equation and a hyperbolic equation with lag could be used to describe the biofilm formation of Geobacillus and Anoxybacillus, respectively. The highest biofilm formation amount was obtained at 60°C for both Geobacillus and Anoxybacillus. However, the biofilm formation rates indicated that the lowest rates of formation were obtained at 60°C for Geobacillus. Moreover, biofilm formation rates of G. thermodenitrificans (1.2-1.6 Log10CFU/mL·h) were higher than G. thermoglucosidans (0.4-0.7 Log10CFU/mL·h). Although A. flavithermus had the highest formation rate values (2.7-3.6 Log10CFU/mL·h), this was attained after the lag period (4 or 5 h). This study revealed that modeling could be used to describe the biofilm formation of thermophilic bacilli in milk.}, } @article {pmid33987107, year = {2021}, author = {Lahiri, D and Nag, M and Banerjee, R and Mukherjee, D and Garai, S and Sarkar, T and Dey, A and Sheikh, HI and Pathak, SK and Edinur, HA and Pati, S and Ray, RR}, title = {Amylases: Biofilm Inducer or Biofilm Inhibitor?.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {660048}, pmid = {33987107}, issn = {2235-2988}, mesh = {*Amylases ; Anti-Bacterial Agents ; *Biofilms ; Fimbriae, Bacterial ; Streptococcus ; }, abstract = {Biofilm is a syntrophic association of sessile groups of microbial cells that adhere to biotic and abiotic surfaces with the help of pili and extracellular polymeric substances (EPS). EPSs also prevent penetration of antimicrobials/antibiotics into the sessile groups of cells. Hence, methods and agents to avoid or remove biofilms are urgently needed. Enzymes play important roles in the removal of biofilm in natural environments and may be promising agents for this purpose. As the major component of the EPS is polysaccharide, amylase has inhibited EPS by preventing the adherence of the microbial cells, thus making amylase a suitable antimicrobial agent. On the other hand, salivary amylase binds to amylase-binding protein of plaque-forming Streptococci and initiates the formation of biofilm. This review investigates the contradictory actions and microbe-associated genes of amylases, with emphasis on their structural and functional characteristics.}, } @article {pmid33984794, year = {2021}, author = {Jiang, R and Xiang, M and Chen, W and Zhang, P and Wu, X and Zhu, G and Tu, T and Jiang, D and Yao, X and Luo, Y and Yang, Z and Chen, D and Wang, Y}, title = {Biofilm characteristics and transcriptomic analysis of Haemophilus parasuis.}, journal = {Veterinary microbiology}, volume = {258}, number = {}, pages = {109073}, doi = {10.1016/j.vetmic.2021.109073}, pmid = {33984794}, issn = {1873-2542}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial/*physiology ; Haemophilus parasuis/*physiology ; Microbial Sensitivity Tests ; Transcriptome/*physiology ; }, abstract = {Haemophilus parasuis (H. parasuis) is a conditional pathogen with the ability to form biofilms which can lead to ineffective drug treatment and severe chronic infections resulting in significant economic losses to the pig industry. Currently, knowledge of biofilm formation by H. parasuis is not well developed. The objective of this study was to investigate the three-dimensional morphology of biofilms and perform transcriptomic analysis on H. parasuis cells in biofilm versus planktonic forms. The results showed that proteins and DNA accounted for a large proportion of the H. parasuis biofilm extracellular matrix. Here, we have traced the entire biofilm formation process of H. parasuis from beginning to end for the first time. These biofilms grew rapidly in the first 48 h and became stable at 60 h. According to GO and KEGG analysis, the differentially expressed genes (DEG) artM, artQ, ssrS, pflA and HutX were implicated as being involved in bacterial colonisation and adhesion; these are the most likely genes to affect biofilm formation. Most functional gene enrichments were of those involved in metabolic pathways, biosynthesis of secondary metabolites, ATP-binding cassette (ABC) transporters, and starch and sucrose metabolism. Thus, in the present pilot study, the composition and characteristics of these biofilms were explored, and the genes related to biofilm formation were screened for. This research lays the foundation for further studies on mechanisms regulating biofilm formation, in order to find new drug targets and develop new therapeutic drugs against H. parasuis.}, } @article {pmid33984692, year = {2021}, author = {Lin, Z and Long, M and Liu, W and Liu, T and Li, F and Wu, Y}, title = {Distinct biofilm formation regulated by different culture media: Implications to electricity generation.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {140}, number = {}, pages = {107826}, doi = {10.1016/j.bioelechem.2021.107826}, pmid = {33984692}, issn = {1878-562X}, mesh = {*Bioelectric Energy Sources ; Biofilms/*growth & development ; Culture Media/*chemistry ; Electrodes ; Shewanella/physiology ; }, abstract = {Biofilm of Shewanella oneidensis MR-1 is extensively studied as it can transform organic compounds directly into electricity. Although revealing the biofilm regulation mechanism is crucial for enhancing bio-current, studies regarding the mechanism by which the culture condition affects biofilm formation are still lacking. The biofilm formation of S. oneidensis MR-1 in two typical media with same electron donor was investigated in this study. Bio-electricity increased 1.8 times in medium with phosphate-buffered saline (PBS) than in piperazine-1,4-bisethanesulfonic acid (PIPES). Biofilm total protein has 1.5-fold of difference between two media at day 3, and biofilm structures also differed; a fluffy biofilm with curled cells was formed in medium with PBS, whereas a compact, ordered, and closely attached biofilm was formed in medium with PIPES. Transcriptome studies clarified that the expression of genes beneficial for cell aggregation [e.g., aggA (2.3 fold), bpfA (2.8 fold) and csgB (3.9 fold)] in medium with PIPES was significantly upregulated, thus provided an explanation for the specific biofilm structure. Buffer concentration was proved to be a critical factor impacted cell morphology and current generation. The maximum current density in 30 mM of PBS and PIPES is 165 and 159 μA·cm[-2] respectively, but it increased to 327 and 274 μA·cm[-2] in 200 mM of PBS and PIPES. This study provides new insights into the mechanism of medium-dependent biofilm regulation, which will be beneficial for developing simple and efficient strategies to enhance bio-electricity generation.}, } @article {pmid33982975, year = {2021}, author = {Schlatterer, D}, title = {CORR Insights®: Tolerant Small-colony Variants Form Prior to Resistance Within a Staphylococcus aureus Biofilm Based on Antibiotic Selective Pressure.}, journal = {Clinical orthopaedics and related research}, volume = {479}, number = {7}, pages = {1482-1483}, pmid = {33982975}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Humans ; *Staphylococcal Infections/diagnosis/drug therapy ; *Staphylococcus aureus ; }, } @article {pmid33981762, year = {2021}, author = {Tomlinson, KL and Riquelme, SA}, title = {Host-bacteria metabolic crosstalk drives S. aureus biofilm.}, journal = {Microbial cell (Graz, Austria)}, volume = {8}, number = {5}, pages = {106-107}, doi = {10.15698/mic2021.05.749}, pmid = {33981762}, issn = {2311-2638}, abstract = {Staphylococcus aureus is a prominent pathogen that can cause intractable lung infections in humans. S. aureus persists in the airway despite inflammation and immune cell recruitment by adapting to host-derived antimicrobial factors. A key component of the immune response to infection are host metabolites that regulate inflammation and bacterial survival. In our recent paper (Tomlinson et al., Nat Commun, doi: 10.1038/s41467-021-21718-y), we demonstrated that S. aureus induces the production of the immunoregulatory metabolite itaconate in airway immune cells by stimulating mitochondrial oxidant stress. Itaconate in turn inhibited S. aureus glycolysis and growth, and promoted carbon flux through bacterial metabolic pathways that support biofilm production. These itaconate-induced metabolic changes were recapitulated in a longitudinal series of clinical isolates from a patient with chronic staphylococcal lung infections, demonstrating a role for host immunometabolism in driving bacterial persistence during long-term staphylococcal lung infections.}, } @article {pmid33980683, year = {2021}, author = {De Leόn, KB}, title = {mSphere of Influence: Surface Sensing in Biofilm Formation.}, journal = {mSphere}, volume = {6}, number = {3}, pages = {}, pmid = {33980683}, issn = {2379-5042}, mesh = {Bacteria/*metabolism ; Bacterial Adhesion ; Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Pseudomonas aeruginosa/growth & development/physiology ; Surface Properties ; }, abstract = {Kara B. De Leόn works in the field of microbial ecology, environmental biofilms, and microbial genetics. In this mSphere of Influence article, she reflects on how the paper "Multigenerational memory and adaptive adhesion in early bacterial biofilm communities" by C. K. Lee et al. (C. K. Lee, J. de Anda, A. E. Baker, R. R. Bennett, et al., Proc Natl Acad Sci U S A 115:4471-4476, 2018, https://dx.doi.org/10.1073/pnas.1720071115) made an impact on her by changing the way she thinks about initial cell attachment to a surface in an environment.}, } @article {pmid33978196, year = {2021}, author = {Zhu, C and Hong, FH and Yu, X}, title = {Anti biofilm effect of low concentration chlorine containing disinfectant assisted by multi enzyme detergent in dental unit waterlines.}, journal = {The new microbiologica}, volume = {44}, number = {2}, pages = {117-124}, pmid = {33978196}, issn = {1121-7138}, mesh = {Biofilms ; Chlorine ; Colony Count, Microbial ; Dental Equipment ; Detergents/pharmacology ; *Disinfectants/pharmacology ; Equipment Contamination ; Extracellular Polymeric Substance Matrix ; Humans ; Water Microbiology ; }, abstract = {The highly structured biofilms on the surface of internal tubing are regarded as the most important source of water pollution in the dental unit waterline (DUWL). Herein, the study aimed to evaluate the anti-biofilm effect of combined application of chlorine-containing disinfectant with multi-enzyme detergent in the dental unit waterline. Six dental units were included and randomly divided into two groups - Group A was treated with chlorine-containing disinfectant and multi-enzyme detergent; Group B was treated only with chlorine-containing disinfectant as control. All groups were treated once a day for four weeks. The anti-biofilm effect was evaluated by heterotrophic plate counts in output water, structure of biofilms, and fluorescence density of biofilms before and after treatment. Abundant opportunistic bacteria forming dense biofilms were observed before treatment. After one week, scanning electron microscopy showed the extracellular polymeric substance of biofilms in Group A was partially destroyed. The biofilms of Group A were completely removed in the third week, while the biofilms of Group B were still present. The combined application of chlorine-containing disinfectant and multi-enzyme detergent achieved a satisfactory effect on biofilms removal, demonstrating this strategy may play a significant role in reducing contamination in the dental clinic.}, } @article {pmid33978026, year = {2021}, author = {Bertsch, P and Etter, D and Fischer, P}, title = {Transient in situ measurement of kombucha biofilm growth and mechanical properties.}, journal = {Food & function}, volume = {12}, number = {9}, pages = {4015-4020}, doi = {10.1039/d1fo00630d}, pmid = {33978026}, issn = {2042-650X}, mesh = {Acetobacteraceae/*growth & development/metabolism ; Biofilms/*growth & development ; Cellulose/metabolism ; Elasticity ; Fermentation ; Kombucha Tea/*microbiology ; Rheology ; }, abstract = {Kombucha is a traditional beverage obtained by the fermentation of sugared tea by a symbiotic culture of bacteria and yeast which has recently re-emerged as a popular lifestyle product with potential health benefits. The characteristic feature of kombucha is the formation of a cellulosic biofilm due to the excretion of bacterial cellulose with high purity and crystallinity. Despite the growing industrial and technological interest in kombucha, current characterization techniques rely on the periodic sampling of tea broth or biofilm and ex situ analysis of its biochemical or microbial composition. Here, we use interfacial shear rheology (ISR) for the transient in situ determination of kombucha biofilm growth directly at the interface. ISR revealed that kombucha biofilm formation is a two step process with clearly distinguishable growth phases. The first phase can be attributed to the initial adsorption of bacteria at the air-water interface and shows great variability, probably due to varying bacteria content and composition. The second phase is initiated by bacterial cellulose excretion and shows astonishing reproducibility regarding onset and final mechanical properties. Hence, ISR qualifies as a new in situ characterization technique for kombucha biofilm growth and bacterial cellulose production.}, } @article {pmid33975142, year = {2021}, author = {Yang, S and Peng, Y and Zhang, S and Han, X and Li, J and Zhang, L}, title = {Carrier type induces anammox biofilm structure and the nitrogen removal pathway: Demonstration in a full-scale partial nitritation/anammox process.}, journal = {Bioresource technology}, volume = {334}, number = {}, pages = {125249}, doi = {10.1016/j.biortech.2021.125249}, pmid = {33975142}, issn = {1873-2976}, abstract = {In this study, two typical carrier types, microporous and macroporous carriers, were collected from a full-scale partial nitritation/anammox reactor for analysis and comparison of the biofilm structure characteristics, performance and removal nitrogen pathway. For microporous carriers, a thicker biofilm (>5 mm) was obtained with higher biomass and abundance of anammox bacteria as well as a higher nitrogen removal efficiency due to the integration of denitrifying and anammox bacteria. In addition, higher microbial community stability can be expected under varying environmental conditions. In comparison, macroporous carrier biofilm exhibited a lower thickness (0.4-2.3 mm) and lower microbial richness, with a strong network correlation among genera. Analysis showed that the mainly positive correlation between anammox bacteria and ammonium oxidizing bacteria, enhancing coupling partial nitritation and anammox. These findings help further our understanding of the mechanisms of anammox biofilm nitrogen removal and provide a baseline for optimization of the design of carrier structures.}, } @article {pmid33973608, year = {2021}, author = {Schriefer, MG and Schrey, H and Zeng, H and Stadler, M and Schobert, R}, title = {Synthesis of the fungal macrolide berkeleylactone A and its inhibition of microbial biofilm formation.}, journal = {Organic & biomolecular chemistry}, volume = {19}, number = {21}, pages = {4743-4751}, doi = {10.1039/d1ob00717c}, pmid = {33973608}, issn = {1477-0539}, mesh = {*Macrolides ; }, abstract = {The fungal macrolide berkeleylactone A was synthesised in 13 steps and 24% yield using (R)-propylene oxide and an asymmetric Noyori hydrogenation of a β-ketoester to install the stereogenic centres. A domino addition-Wittig olefination of a 13-hydroxytetradecanal intermediate with the cumulated ylide Ph3PCCO closed the macrocyle by establishing the α,β-unsaturated ester group, necessary for the attachment of the sidechain thiol via a thia-Michael reaction. The synthetic berkeleylactone A inhibited the formation of Staphylococcus aureus biofilms and showed significant dispersive effects on preformed biofilms of Candida albicans by at least 45% relative to untreated controls at concentrations as low as 1.3 μg mL-1.}, } @article {pmid33972577, year = {2021}, author = {Alsenafi, A and Bég, OA and Ferdows, M and Bég, TA and Kadir, A}, title = {Numerical study of nano-biofilm stagnation flow from a nonlinear stretching/shrinking surface with variable nanofluid and bioconvection transport properties.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {9877}, pmid = {33972577}, issn = {2045-2322}, abstract = {A mathematical model is developed for stagnation point flow toward a stretching or shrinking sheet of liquid nano-biofilm containing spherical nano-particles and bioconvecting gyrotactic micro-organisms. Variable transport properties of the liquid (viscosity, thermal conductivity, nano-particle species diffusivity) and micro-organisms (species diffusivity) are considered. Buongiorno's two-component nanoscale model is deployed and spherical nanoparticles in a dilute nanofluid considered. Using a similarity transformation, the nonlinear systems of partial differential equations is converted into nonlinear ordinary differential equations. These resulting equations are solved numerically using a central space finite difference method in the CodeBlocks Fortran platform. Graphical plots for the distribution of reduced skin friction coefficient, reduced Nusselt number, reduced Sherwood number and the reduced local density of the motile microorganisms as well as the velocity, temperature, nanoparticle volume fraction and the density of motile microorganisms are presented for the influence of wall velocity power-law index (m), viscosity parameter [Formula: see text], thermal conductivity parameter (c4), nano-particle mass diffusivity (c6), micro-organism species diffusivity (c8), thermophoresis parameter [Formula: see text], Brownian motion parameter [Formula: see text], Lewis number [Formula: see text], bioconvection Schmidt number [Formula: see text], bioconvection constant (σ) and bioconvection Péclet number [Formula: see text]. Validation of the solutions via comparison related to previous simpler models is included. Further verification of the general model is conducted with the Adomian decomposition method (ADM). Extensive interpretation of the physics is included. Skin friction is elevated with viscosity parameter ([Formula: see text] whereas it is suppressed with greater Lewis number and thermophoresis parameter. Temperatures are elevated with increasing thermal conductivity parameter ([Formula: see text] whereas Nusselt numbers are reduced. Nano-particle volume fraction (concentration) is enhanced with increasing nano-particle mass diffusivity parameter ([Formula: see text]) whereas it is markedly reduced with greater Lewis number (Le) and Brownian motion parameter (Nb). With increasing stretching/shrinking velocity power-law exponent ([Formula: see text] skin friction is decreased whereas Nusselt number and Sherwood number are both elevated. Motile microorganism density is boosted strongly with increasing micro-organism diffusivity parameter ([Formula: see text]) and Brownian motion parameter (Nb) but reduced considerably with greater bioconvection Schmidt number (Sc) and bioconvection Péclet number (Pe). The simulations find applications in deposition processes in nano-bio-coating manufacturing processes.}, } @article {pmid33971542, year = {2021}, author = {Hu, P and Lv, B and Yang, K and Lu, Z and Ma, J}, title = {Discovery of myricetin as an inhibitor against Streptococcus mutans and an anti-adhesion approach to biofilm formation.}, journal = {International journal of medical microbiology : IJMM}, volume = {311}, number = {4}, pages = {151512}, doi = {10.1016/j.ijmm.2021.151512}, pmid = {33971542}, issn = {1618-0607}, mesh = {Biofilms ; *Dental Caries/prevention & control ; Flavonoids/pharmacology ; Humans ; *Streptococcus mutans ; }, abstract = {Streptococcus mutans (S. mutans) are cariogenic microorganisms. Sortase A (SrtA) is a transpeptidase that attaches Pac to the cell surface. The biofilm formation of S. mutans is promoted by SrtA regulated Pac. Myricetin (Myr) has a variety of pharmacological properties, including inhibiting SrtA activity of Staphylococcus aureus. The purpose of this research was to investigate the inhibitory effect of Myr on SrtA of S. mutans and its subsequent influence on the biofilm formation. Here, Myr was discovered as a potent inhibitor of S. mutans SrtA, with an IC50 of 48.66 ± 1.48 μM, which was lower than the minimum inhibitory concentration (MIC) of 512 ug/mL. Additionally, immunoblot and biofilm assays demonstrated that Myr at a sub-MIC level could reduce adhesion and biofilm formation of S. mutans. The reduction of biofilm was possibly caused by the decreased amount of Pac on the cells' surface by releasing Pac into the medium via inhibiting SrtA activity. Molecular dynamics simulations and mutagenesis assays suggested that Met123, Ile191, and Arg213 of SrtA were pivotal for the interaction of SrtA and Myr. Our findings indicate that Myr is a promising candidate for the control of dental caries by modulating Pac-involved adhesive mechanisms without developing drug resistance to S.mutans.}, } @article {pmid33971131, year = {2021}, author = {Wen, HQ and Ren, HY and Xie, GJ and Xing, DF and Ren, NQ and Liu, BF}, title = {Accelerated start-up for photo-fermentative hydrogen production in biofilm reactor by adding waste effluent.}, journal = {Environmental research}, volume = {198}, number = {}, pages = {111221}, doi = {10.1016/j.envres.2021.111221}, pmid = {33971131}, issn = {1096-0953}, mesh = {*Biofilms ; Bioreactors ; Fermentation ; Hydrogen ; Quorum Sensing ; *Waste Disposal, Fluid ; }, abstract = {The difficulty and long duration of start-up wastes numerous costs, labors and time and a little fluctuate during the process might fail it. However, studies dealing with the problem hindering accelerated start-up are still insufficient. Current research focused to develop a method for accelerated start-up in an efficient way. This work outlined a novel alternative for accelerated start-up. This joint method, adding waste effluent with applying biofilm reactor, could successfully start up hydrogen production in the first 24 h via increasing ability of hydrogen producers while the control group produced little hydrogen. The two factors, biofilm formation and addition of waste effluent, expressed the combined effects on accelerated start-up. This study suggested that little molecules like quorum sensing system factors and indoles might be the crucial regulating and stimulating factors and express the accelerated start-up ability only in biofilm reactors.}, } @article {pmid33968582, year = {2021}, author = {Vandana, and Das, S}, title = {Structural and mechanical characterization of biofilm-associated bacterial polymer in the emulsification of petroleum hydrocarbon.}, journal = {3 Biotech}, volume = {11}, number = {5}, pages = {239}, pmid = {33968582}, issn = {2190-572X}, abstract = {UNLABELLED: The marine bacterium Pseudomonas furukawaii PPS-19 isolated from the oil-polluted site of Paradip port, Odisha, India, was found to form a strong biofilm in 2% (v/v) crude oil. Confocal Laser Scanning Microscopy (CLSM) revealed biofilm components along with multi-layered dense biofilm of rod-shaped cells with 64.7 µm thickness. Scanning electron micrographs showed similar biofilm architecture covered with a gluey matrix of extracellular polymeric substances (EPS) in the presence of 2% (v/v) crude oil. The architecture of purified EPS was also studied through FESEM that exposed its porous and three-dimensional flakes-like structure. The structural characterization by FTIR revealed that EPS was composed of primary alkane, amines, halide, hydroxyl groups, uronic acid, and saccharides. The XRD profile exhibited an amorphous phase of the EPS with a crystallinity index of 0.336. The EPS showed three-step thermal decomposition and thermal stability up to 600 °C, as confirmed by TGA and DSC thermogram. EPS produced by marine bacterium P. furukawaii PPS-19 could act as bioemulsifier and showed the highest emulsifying activity of 66.23% on petrol. The emulsifying ability of the EPS was superior to the commercial polymer xanthan. The emulsion also showed high stability with time and temperature exposure. The marine bacterium P. furukawaii PPS-19 and the EPS complex showed 89.52% degradation of crude oil within 5 days. These properties demonstrated the potential of biofilm-forming marine bacterium as bioemulsifier for its application in the bioremediation of oil-polluted sites.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02795-8.}, } @article {pmid33968313, year = {2021}, author = {Verspecht, T and Van Holm, W and Boon, N and Bernaerts, K and Daep, CA and Masters, JG and Zayed, N and Quirynen, M and Teughels, W}, title = {Potential prebiotic substrates modulate composition, metabolism, virulence and inflammatory potential of an in vitro multi-species oral biofilm.}, journal = {Journal of oral microbiology}, volume = {13}, number = {1}, pages = {1910462}, pmid = {33968313}, issn = {2000-2297}, abstract = {Background: Modulation of the commensal oral microbiota constitutes a promising preventive/therapeutic approach in oral healthcare. The use of prebiotics for maintaining/restoring the health-associated homeostasis of the oral microbiota has become an important research topic. Aims: This study hypothesised that in vitro 14-species oral biofilms can be modulated by (in)direct stimulation of beneficial/commensal bacteria with new potential prebiotic substrates tested at 1 M and 1%(w/v), resulting in more host-compatible biofilms with fewer pathogens, decreased virulence and less inflammatory potential. Methods: Established biofilms were repeatedly rinsed with N-acetyl-D-glucosamine, α-D-lactose, D-(+)-trehalose or D-(+)-raffinose at 1 M or 1%(w/v). Biofilm composition, metabolic profile, virulence and inflammatory potential were eventually determined. Results: Repeated rinsing caused a shift towards a more health-associated microbiological composition, an altered metabolic profile, often downregulated virulence gene expression and decreased the inflammatory potential on oral keratinocytes. At 1 M, the substrates had pronounced effects on all biofilm aspects, whereas at 1%(w/v) they had a pronounced effect on virulence gene expression and a limited effect on inflammatory potential. Conclusion: Overall, this study identified four new potential prebiotic substrates that exhibit different modulatory effects at two different concentrations that cause in vitro multi-species oral biofilms to become more host-compatible.}, } @article {pmid33967997, year = {2021}, author = {Coppola, GA and Onsea, J and Moriarty, TF and Nehrbass, D and Constant, C and Zeiter, S and Aktan, MK and Braem, A and Van der Eycken, EV and Steenackers, HP and Metsemakers, WJ}, title = {An Improved 2-Aminoimidazole Based Anti-Biofilm Coating for Orthopedic Implants: Activity, Stability, and in vivo Biocompatibility.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {658521}, pmid = {33967997}, issn = {1664-302X}, abstract = {Orthopedic device-related infections remain a serious challenge to treat. Central to these infections are bacterial biofilms that form on the orthopedic implant itself. These biofilms shield the bacteria from the host immune system and most common antibiotic drugs, which renders them essentially antibiotic-tolerant. There is an urgent clinical need for novel strategies to prevent these serious infections that do not involve conventional antibiotics. Recently, a novel antibiofilm coating for titanium surfaces was developed based on 5-(4-bromophenyl)-N-cyclopentyl-1-octyl-1H-imidazol-2-amine as an active biofilm inhibitor. In the current study we present an optimized coating protocol that allowed for a 5-fold higher load of this active compound, whilst shortening the manufacturing process. When applied to titanium disks, the newly optimized coating was resilient to the most common sterilization procedures and it induced a 1 log reduction in biofilm cells of a clinical Staphylococcus aureus isolate (JAR060131) in vitro, without affecting the planktonic phase. Moreover, the antibiofilm effect of the coating in combination with the antibiotic cefuroxime was higher than cefuroxime treatment alone. Furthermore, the coating was successfully applied to a human-scale fracture fixation device resulting in a loading that was comparable to the titanium disk model. Finally, an in vivo biocompatibility and healing study in a rabbit osteotomy model indicated that these coated implants did not negatively affect fracture healing or osteointegration. These findings put our technology one step closer to clinical trials, confirming its potential in fighting orthopedic infections without compromising healing.}, } @article {pmid33965751, year = {2021}, author = {Chatterjee, T and Saha, T and Sarkar, P and Hoque, KM and Chatterjee, BK and Chakrabarti, P}, title = {The gold nanoparticle reduces Vibrio cholerae pathogenesis by inhibition of biofilm formation and disruption of the production and structure of cholera toxin.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {204}, number = {}, pages = {111811}, doi = {10.1016/j.colsurfb.2021.111811}, pmid = {33965751}, issn = {1873-4367}, mesh = {Animals ; Biofilms ; Cholera Toxin ; Gold ; *Metal Nanoparticles ; Mice ; *Vibrio cholerae ; }, abstract = {Formation of biofilm by Vibrio cholerae plays a crucial role in pathogenesis and transmission of cholera. Lower infective dose of the biofilm form of V. cholerae compared to the planktonic counterpart, and its antibiotic resistance, make it challenging to combat cholera. Nanoparticles may serve as an effective alternative to conventional antibiotics for targeting biofilms and virulence factors. We explored the effectiveness of gold nanoparticles (AuNPs) of different size and shape (spherical: AuNS10 and AuNS100, and rod: AuNR10, the number indicating the diameter in nm) on both the inhibition of formation and eradication of biofilm of the two biotypes of V. cholerae, classical (VcO395) and El Tor (VcN16961). Inhibition of biofilm formation by spherical AuNPs was observed for both the biotypes. Considering eradication, the biofilms for both, particularly El Tor, was destroyed using both the AuNSs, AuNS100 showing higher efficacy. AuNR10 did not affect the biofilm of either biotype. Micrographs of small intestinal sections of VcO395-infected mice indicated the inhibition of biofilm formation by both AuNSs. We also studied the effect of these AuNPs on the structure of cholera toxin (CT), the major toxin produced by V. cholerae. Far-UV CD showed both AuNR10 and AuNS100 compromised the structure of CT, which was also validated from the reduction of fluid accumulation in mice ileal loop. Western blot analysis revealed the reduction of CT production upon treatment with AuNPs. AuNS100 seems to be the best suited to inhibit the formation or destruction of biofilm, as well as to disrupt CT production and function.}, } @article {pmid33965251, year = {2021}, author = {Zhou, Y and Matin, K and Shimada, Y and Sadr, A and Wang, G and Tagami, J and Feng, X}, title = {Characteristics of biofilm-induced degradation at resin-dentin interfaces using multiple combinations of adhesives and resins.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {37}, number = {8}, pages = {1260-1272}, doi = {10.1016/j.dental.2021.04.007}, pmid = {33965251}, issn = {1879-0097}, mesh = {Adhesives ; Animals ; Biofilms ; Cattle ; Composite Resins ; *Dental Bonding ; Dental Cements ; Dental Materials ; *Dentin ; Dentin-Bonding Agents ; Materials Testing ; Microscopy, Electron, Scanning ; Resin Cements ; Surface Properties ; }, abstract = {OBJECTIVE: We aimed to evaluate morphological, mechanical and chemical characteristics at resin-dentin interfaces using multiple combinations of adhesives and resins after a short-term biofilm-induced degradation.

METHODS: Cervical cavities were prepared in bovine incisors, treated by Clearfil SE Bond 2 (SE) or FL-Bond II (FL), restored by Clearfil Majesty ES Flow (ES) or Beautifil Flow Plus (BFP) and grouped into SE-ES, SE-BFP, FL-ES and FL-BFP. After biofilm challenge, interfacial gaps and dentin wall lesions were examined by optical coherence tomography (OCT). Gap depth (GD), gap pattern scale (GPS) and dentin wall lesion depth (WLD) were evaluated from confocal laser scanning microscope. Microhardness of dentin lesions was measured with a Vickers microhardness tester. Chemical elements in resins and dentin wall lesions were analyzed by scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDS). Morphological structures of interfacial gaps were observed by SEM.

RESULTS: OCT could detect adhesive-dentin-bonded and adhesive-dentin-debonded gaps. SE-containing groups showed significantly lower GPS than FL-containing groups. FL-BFP showed significantly lower WLD than FL-ES. Microhardness of dentin wall lesions was higher than that of outer lesions and they showed significant differences in FL-BFP. SE-BFP showed a lower GPS curve and higher intensities of Ca and P in the upper half of dentin wall lesions than other groups. From SEM, microgaps between filler and matrix, break and loss of matrix, separation of adhesive matrix with hybrid layer occurred at interfacial gaps.

SIGNIFICANCE: The morphological, mechanical and chemical characteristics of resin-dentin interfacial degradation depend on the component and chemistry of restorative materials.}, } @article {pmid33965115, year = {2021}, author = {Peng, Y and Wang, Z and Zhou, Y and Wang, F and Zhang, S and He, D and Deng, L}, title = {Ferrocene-functionalized hybrid hydrogel dressing with high-adhesion for combating biofilm.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {125}, number = {}, pages = {112111}, doi = {10.1016/j.msec.2021.112111}, pmid = {33965115}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/pharmacology ; Bandages ; Biofilms ; *Hydrogels ; *Hydrogen Peroxide ; Metallocenes ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Bacterial infection is a common phenomenon in the process of postoperative wound healing. In severe cases, it may even lead to life-threatening, which brings a heavy burden to the clinical treatment and causes huge losses to the society and economy. As one of the most commonly applied medical materials for wound treatment, hydrogel dressings are mainly used to cover and protect wounds and provide a favorable environment to facilitate wound healing. In this work, we developed an antibacterial hydrogel dressing (Fc-PAAM) with high adhesion, which is consisted of polyacrylamide (PAM) hydrogel framework and polyacrylic acid-functionalized (PAA) with ferrocene (Fc). Morphology, adhesion and pressure resistance of PAAM hydrogel were confirmed by using scanning electron microscope (SEM) and universal testing machine, and Fc decoration in the hydrogel network was well demonstrated by using Fourier transform infrared spectroscopy (FT-IR). Ultraviolet-visible spectroscopy (UV-vis) displayed that the Fc-PAAM hydrogel had excellent peroxidase-like activity as well. It not only exhibited prominent antimicrobial activity against Gram (+/-) bacteria, but also performed high efficiency in preventing the formation of biofilms. In addition, in vivo experiments indicated that this adhesive dressing could significantly prevent bacterial infections. Compared with other clinical treatment methods, this kind of hydrogel is not easy to cause bacterial resistance, and the used raw materials are easy to obtain and low in price, which can amplify the antibacterial properties of H2O2 and provide a new opportunity for the treatment of clinical bacterial infections.}, } @article {pmid33964752, year = {2021}, author = {Zhang, L and Zhang, Y and Zhang, Y and Gamal El-Din, M}, title = {Application of an indigenous microorganisms-based fixed-bed GAC-biofilm reactor for passive and sustainable treatment of oil sands process water through combined adsorption and biodegradation processes.}, journal = {Chemosphere}, volume = {280}, number = {}, pages = {130635}, doi = {10.1016/j.chemosphere.2021.130635}, pmid = {33964752}, issn = {1879-1298}, mesh = {Adsorption ; Biodegradation, Environmental ; Biofilms ; Carboxylic Acids ; *Charcoal ; Humans ; Oil and Gas Fields ; Water ; *Water Pollutants, Chemical/analysis ; }, abstract = {In this study, a fixed-bed biofilm reactor (biofilter) was developed and applied for oil sands process water (OSPW) remediation by using granular activated carbon (GAC) as packing media. Using quantitative polymerase chain reaction (qPCR) detection, the total bacterial copy number (16S) in the GAC biofiltration system was found to reach a relatively stable level (1.3 ± 0.2 × 10[9] copies/g GAC) after 62 days of operation, and the thickness of biofilm on GAC surface was 26.7 ± 4.3 μm based on the scan of confocal laser scanning microscopy (CLSM). The established GAC-biofilter showed 95.4% naphthenic acids (NAs) removal from raw OSPW after 2 months of operation. The GAC-biofilter also showed 88.3% NAs removal after a long operation time (2 years), indicating its sustainable bioremediation capacity for OSPW. 16S and 18S rRNA gene-targeted metagenomic sequencing showed that the microbial community in the GAC biofilter had higher diversity and richness than that found in the sand biofilter which was used for OSPW treatment previously. Comamonadaceae and Saccharomycotina were found to be the dominant bacterial and fungal families in the GAC biofilter, respectively. Xenobiotic metabolism function of the microbial community may contribute significantly to the biodegradation of NAs. The GAC biofiltration process is a promising passive OSPW treatment approach that can be used in-situ.}, } @article {pmid33963526, year = {2022}, author = {Di Bonaventura, G and Pompilio, A}, title = {In Vitro Antimicrobial Susceptibility Testing of Biofilm-Growing Bacteria: Current and Emerging Methods.}, journal = {Advances in experimental medicine and biology}, volume = {1369}, number = {}, pages = {33-51}, pmid = {33963526}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteria ; *Biofilms ; Humans ; Microbial Sensitivity Tests ; Plankton ; *Pseudomonas aeruginosa ; }, abstract = {The antibiotic susceptibility of bacterial pathogens is typically determined based on planktonic cells, as recommended by several international guidelines. However, most of chronic infections - such as those established in wounds, cystic fibrosis lung, and onto indwelling devices - are associated to the formation of biofilms, communities of clustered bacteria attached onto a surface, abiotic or biotic, and embedded in an extracellular matrix produced by the bacteria and complexed with molecules from the host. Sessile microorganisms show significantly increased tolerance/resistance to antibiotics compared with planktonic counterparts. Consequently, antibiotic concentrations used in standard antimicrobial susceptibility tests, although effective against planktonic bacteria in vitro, are not predictive of the concentrations required to eradicate biofilm-related infections, thus leading to treatment failure, chronicization and removal of material in patients with indwelling medical devices.Meeting the need for the in vitro evaluation of biofilm susceptibility to antibiotics, here we reviewed several methods proposed in literature highlighting their advantages and limitations to guide scientists towards an appropriate choice.}, } @article {pmid33963217, year = {2021}, author = {Ibrahim, AM and Hamouda, RA and El-Naggar, NE and Al-Shakankery, FM}, title = {Bioprocess development for enhanced endoglucanase production by newly isolated bacteria, purification, characterization and in-vitro efficacy as anti-biofilm of Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {9754}, pmid = {33963217}, issn = {2045-2322}, mesh = {*Bacillus subtilis/enzymology/isolation & purification ; *Bacterial Proteins/chemistry/isolation & purification/pharmacology ; Biofilms/*drug effects/growth & development ; *Cellulase/chemistry/isolation & purification/pharmacology ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Endoglucanase producing bacteria were isolated from Egyptian soils and the most active bacterial strain was identified as Bacillus subtilis strain Fatma/1. Plackett-Burman statistical design was carried out to assess the effect of seven process variables on endoglucanase production. Carboxymethyl cellulose (CMC), yeast extract and peptone were the most significant variables that enhanced the endoglucanase production and thus were selected for further optimization using face-centered central composite design. The highest yield of endoglucanase (32.37 U/mL) was obtained in run no. 9, using 18 g/L CMC, 8 g/L peptone, 7 g/L yeast extract and 0.1 g/L FeSO4.7H2O. The optimized medium showed about eightfold increase in endoglucanase production compared to the unoptimized medium. The produced crude enzyme was further purified by ammonium sulfate precipitation, then DEAE-Sepharose CL6B column. The purified enzyme was shown to have a molecular weight of 37 kDa. The enzyme showed maximum activity at pH 8.0, temperature of 50 °C, incubation time of 60 min. The half-life time (T1/2) was 139.53 min at 50 °C, while being 82.67 min at 60 °C. Endoglucanase at concentration of 12 U/mL effectively removed 84.61% of biofilm matrix of Pseudomonas aeruginosa with marked reduction in carbohydrate content of the biofilm from 63.4 to 7.9 μg.}, } @article {pmid33963212, year = {2021}, author = {Johnston, W and Rosier, BT and Artacho, A and Paterson, M and Piela, K and Delaney, C and Brown, JL and Ramage, G and Mira, A and Culshaw, S}, title = {Mechanical biofilm disruption causes microbial and immunological shifts in periodontitis patients.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {9796}, pmid = {33963212}, issn = {2045-2322}, support = {300881//Joint studentship between University of Glasgow and Dentsply Sirona/ ; Bio2015-68711-R//Spanish Ministry of Science, Innovation and Universities/ ; RTI2018-102032-B-I00//Spanish Ministry of Science, Innovation and Universities/ ; BB/P504567/1//BBSRC/ ; BB/P504567/1//BBSRC/ ; 290246//EU Marie Curie ITN RAPID/ ; 20823/VAC_/Versus Arthritis/United Kingdom ; }, mesh = {*Bacteria/classification/genetics/immunology ; *Bacterial Physiological Phenomena ; *Biofilms ; Female ; Humans ; Interleukin-1beta/*immunology ; Longitudinal Studies ; Male ; Middle Aged ; *Periodontitis/immunology/microbiology/therapy ; Saliva/*immunology ; }, abstract = {Periodontitis is characterized by subgingival biofilm dysbiosis, inflammation and tissue destruction. Current treatment involves mechanical biofilm disruption known as non-surgical periodontal therapy (NSPT). This study sought to characterise the impact of treatment on microbial diversity and overall community, and the parallel impact on host inflammation in the oral cavity. Fourty-two periodontitis patients were included in this study, with periodontal clinical parameters, subgingival plaque and saliva samples collected at baseline and 90 days after treatment. Salivary cytokines were quantified, and subgingival plaque was analysed using 16S rRNA sequencing. After treatment, there were marked health-associated alterations in microbial composition and diversity, including differential abundance of 42 genera and 61 species. These changes were accompanied by substantial clinical improvement (pockets ≥ 5 mm, 27.50% to 9.00%, p < 0.001) and a decrease in salivary IL-1β (p < 0.001)-a putative marker of periodontal inflammation. Despite significant reductions in disease associated anaerobes, several genera (Fusobacterium, Prevotella, Tanenerella, Treponema) remained present and formed a distinct subnetwork associated with residual disease. Collectively, this study shows that current periodontal treatment results in partial restoration of a healthy microbial ecosystem, but features of biofilm dysbiosis and host inflammation remain in some patients, which were surprisingly independent of clinical response.}, } @article {pmid33962286, year = {2021}, author = {Shitu, A and Liu, G and Zhang, Y and Ye, Z and Zhao, J and Zhu, S and Liu, D}, title = {Enhancement of mariculture wastewater treatment using moving bed biofilm reactors filled with modified biocarriers: Characterisation, process performance and microbial community evaluation.}, journal = {Journal of environmental management}, volume = {291}, number = {}, pages = {112724}, doi = {10.1016/j.jenvman.2021.112724}, pmid = {33962286}, issn = {1095-8630}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; Nitrification ; Taiwan ; Wastewater/analysis ; *Water Purification ; }, abstract = {This research investigated two proposed modified biofilm carriers' performances in treating recirculating aquaculture systems (RAS) wastewater under different salinities (12‰, 26‰, and 35‰) for about 92 days. Three moving bed biofilm reactors (MBBRs; R1, R2, and R3) were filled with unmodified novel sponge biocarriers (SB) served as a control, modified novel SB with ferrous oxalate (C2FeO4@SB), and modified novel SB with combined ferrous oxalate and activated carbon (C2FeO4-AC@SB), respectively. Under the highest saline condition, a significantly higher ammonia removal efficiency of 98.86 ± 0.7% (p ˃ 0.05) was obtained in R3, whereas R2 and R1 yielded 95.18 ± 2.8% and 91.66 ± 1.5%, respectively. Microbial analysis showed that Vibrio, Ruegeria, Formosa, Thalassospira, and Denitromonas were predominant genera, strictly halophilic heterotrophic nitrifying bacteria involved in nitrogen removal. In conclusion, the synergistic effects of novel sponge, C2FeO4 and AC accelerated biofilm formations and stability, subsequently enhanced the removal of ammonia from the mariculture RAS wastewater by the C2FeO4-AC@SB carriers in R3.}, } @article {pmid33962273, year = {2021}, author = {Doose, C and Morin, S and Malbezin, L and Vedrenne, J and Fortin, C}, title = {Effects of thorium on bacterial, microalgal and micromeiofaunal community structures in a periphytic biofilm.}, journal = {Ecotoxicology and environmental safety}, volume = {218}, number = {}, pages = {112276}, doi = {10.1016/j.ecoenv.2021.112276}, pmid = {33962273}, issn = {1090-2414}, abstract = {Few ecotoxicity studies are available on thorium (Th) which hinders the ability to evaluate its ecotoxicological risk. Its release in the environment is often associated with the extraction of rare earth elements and uranium, as well as the field applications of phosphate fertilizers. This study investigates the effects of Th on microbial communities of periphytic biofilms. Ceramic plates were left to colonize for one month in the laboratory with a biofilm sampled from Cap Rouge river (QC, Canada). Plates were randomly placed in channels containing culture media representing three different conditions: a control condition (C0; background Th concentrations of 0.004 ± 0.002 nM), a low Th concentration condition (C1; 0.18 ± 0.09 nM Th) and a moderately high Th condition (C10; 8.7 ± 3.4 nM) for up to 4 weeks. The presence of Th modified the diatom community by changing its taxonomic structure, reducing diversity and increasing cell density. The taxonomic structure of the bacterial community, followed by 16S metabarcoding analysis, was affected with a significant decrease in Pseudanabaena and Shingopyxis genera in the two Th exposed conditions. No direct toxic effect of Th was observed on counted micromeiofauna but the changes in diatom and bacterial communities could explain the higher number of individual diatoms and micromeiofauna observed in Th-exposed conditions. This work shows that low concentrations of Th can modify biofilm structure, which, in turn, could disturb its ecologically key functions.}, } @article {pmid33959808, year = {2022}, author = {Chatrath, A and Kumar, M and Prasad, R}, title = {Comparative proteomics and variations in extracellular matrix of Candida tropicalis biofilm in response to citral.}, journal = {Protoplasma}, volume = {259}, number = {2}, pages = {263-275}, pmid = {33959808}, issn = {1615-6102}, mesh = {Acyclic Monoterpenes ; Antifungal Agents/pharmacology ; Biofilms ; *Candida tropicalis/physiology ; Extracellular Matrix ; Humans ; *Proteomics ; }, abstract = {Candida tropicalis is an opportunistic human pathogen with an ability to cause superficial as well as systemic infections in immunocompromised patients. The formation of biofilm by C. tropicalis can cause dreadful and persistent infections which are difficult to treat due to acquired resistance. Presently, available anti-Candida drugs exhibit a high frequency of resistance, low specificity and toxicity at a higher dosage. In addition, the discovery of natural or synthetic anti-Candida drugs is slow paced and often does not pass clinical trials. Citral, a monoterpene aldehyde, has shown effective antimicrobial activities against various microorganisms. However, only few studies have elaborated the action of citral against the biofilm of C. tropicalis. In the present work, the aim was to study the fungicidal effect, differential expression of proteome and changes in extracellular matrix in response to the sub-lethal concentration (16 µg/mL) of citral. The administration of citral on C. tropicalis biofilm leads to a fungicidal effect. Furthermore, the differential expression of proteome has revealed twenty-five proteins in C. tropicalis biofilm, which were differentially expressed in the presence of citral. Among these, amino acid biosynthesis (Met6p, Gln1p, Pha2p); nucleotide biosynthesis (Xpt1p); carbohydrate metabolism (Eno1p, Fba1p, Gpm1p); sterol biosynthesis (Mvd1p/Erg19p, Hem13p); energy metabolism (Dnm1p, Coa1p, Ndk1p, Atp2p, Atp4p, Hts1p); oxidative stress (Hda2p, Gre22p, Tsa1p, Pst2p, Sod2p) and biofilm-specific (Adh1p, Ape1p, Gsp1p) proteins were identified. The overexpression of oxidative stress-related proteins indicates the response of biofilm cell to combating oxidative stress during citral treatment. Moreover, the upregulation of Adh1p is of particular interest because it subsidizes the biofilm inhibition through ethanol production as a cellular response. The augmented expression of Mvd1p/Erg19p signifies the effect of citral on ergosterol biosynthesis. The presence of citral has also shown an increment in hexosamine and ergosterol component in extracellular matrix of C. tropicalis biofilm. Hence, it is indicated that the cellular response towards citral acts through multifactorial processes. This study will further help in the interpretation of the effect of citral on C. tropicalis biofilm and development of novel antifungal agents against these potential protein targets.}, } @article {pmid33958697, year = {2021}, author = {Kees, ED and Levar, CE and Miller, SP and Bond, DR and Gralnick, JA and Dean, AM}, title = {Survival of the first rather than the fittest in a Shewanella electrode biofilm.}, journal = {Communications biology}, volume = {4}, number = {1}, pages = {536}, pmid = {33958697}, issn = {2399-3642}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Electrodes ; Electron Transport ; Shewanella/*growth & development ; Surface Properties ; }, abstract = {For natural selection to operate there must exist heritable variation among individuals that affects their survival and reproduction. Among free-living microbes, where differences in growth rates largely define selection intensities, competitive exclusion is common. However, among surface attached communities, these dynamics become less predictable. If extreme circumstances were to dictate that a surface population is immortal and all offspring must emigrate, the offspring would be unable to contribute to the composition of the population. Meanwhile, the immortals, regardless of reproductive capacity, would remain unchanged in relative abundance. The normal cycle of birth, death, and competitive exclusion would be broken. We tested whether conditions required to set up this idealized scenario can be approximated in a microbial biofilm. Using two differentially-reproducing strains of Shewanella oneidensis grown on an anode as the sole terminal electron acceptor - a system in which metabolism is obligately tied to surface attachment - we found that selection against a slow-growing competitor is drastically reduced. This work furthers understanding of natural selection dynamics in sessile microbial communities, and provides a framework for designing stable microbial communities for industrial and experimental applications.}, } @article {pmid33956425, year = {2021}, author = {Wang, A and Weldrick, PJ and Madden, LA and Paunov, VN}, title = {Biofilm-Infected Human Clusteroid Three-Dimensional Coculture Platform to Replace Animal Models in Testing Antimicrobial Nanotechnologies.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {19}, pages = {22182-22194}, doi = {10.1021/acsami.1c02679}, pmid = {33956425}, issn = {1944-8252}, mesh = {*Animal Testing Alternatives ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cell Line ; Ciprofloxacin/pharmacology ; Coculture Techniques ; Humans ; Microbial Sensitivity Tests ; *Nanotechnology ; }, abstract = {Microbial biofilms are a major concern in wound care, implant devices, and organ infections. Biofilms allow higher tolerance to antimicrobial drugs, can impair wound healing, and potentially lead to sepsis. There has been a recent focus on developing novel nanocarrier-based delivery vehicles to enhance the biofilm penetration of traditional antibacterial drugs. However, a feasible in vitro human skin model to mimic the biofilm formation and its treatment for clearance have not yet been reported. This study describes the benefits of using an innovative bacterial biofilm-infected keratinocyte clusteroid model for the first time. It paves a new way for testing innovative nanomedicine delivery systems in a rapid and reproducible way on a realistic human cell-based platform, free of any animal testing. Herein, we have developed a novel composite 3D biofilm/human keratinocyte clusteroid coculture platform, which was used to measure biofilm clearance efficiency of nanoparticle (NP)-based therapeutics. We tested this model by treating the biofilm-infected 3D coculture layers by a ciprofloxacin-loaded Carbopol nanogel particles, surface-functionalized by the cationic protease Alcalase. We measured the antibacterial efficiency of the NP treatment on clearing Staphylococcus aureus and Pseudomonas aeruginosa biofilms on the 3D keratinocyte clusteroid/biofilm coculture model. Our experiments showed that these bacteria can infect the 3D layer of keratinocyte clusteroids and produce a stable biofilm. The biofilms were efficiently cleared by treatment with a formulation of 0.0032 wt % ciprofloxacin-loaded in 0.2 wt % Carbopol NPs surface-functionalized with 0.2 wt % Alcalase. Taken together, these promising results demonstrate that our coculture model can be exploited as a novel platform for testing the biofilm-eliminating efficiency of various NP formulations emulating skin and wound infections and could have wider applicability to replace animal models in similar experiments. This 3D cell culture-based platform could help in developing and testing of more effective antibacterial agents for clinical applications of antiplaque dental treatments, implants, infection control, and wound dressings.}, } @article {pmid33955542, year = {2022}, author = {Espíndola, LCP and Picão, RC and Mançano, SMCN and Martins do Souto, R and Colombo, APV}, title = {Prevalence and antimicrobial susceptibility of Gram-negative bacilli in subgingival biofilm associated with periodontal diseases.}, journal = {Journal of periodontology}, volume = {93}, number = {1}, pages = {69-79}, doi = {10.1002/JPER.20-0829}, pmid = {33955542}, issn = {1943-3670}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cross-Sectional Studies ; *Gingivitis ; Gram-Negative Bacteria ; Humans ; Imipenem/pharmacology ; Microbial Sensitivity Tests ; *Periodontal Diseases ; *Periodontitis ; Prevalence ; beta-Lactamases/genetics ; }, abstract = {BACKGROUND: This cross-sectional study aimed to determine the prevalence and antimicrobial susceptibility of Gram-negative bacilli (GNB) isolated from subgingival biofilm of individuals with different periodontal conditions.

METHODS: Subgingival biofilm was obtained from 362 individuals with periodontal health (PH) (n = 83), gingivitis (n = 74), and periodontitis (n = 205), cultivated in broth and selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by the Clinical and Laboratory Standards Institute disk diffusion guidelines. Production of extended-spectrum beta-lactamase (ESBL) and carbapenemases were evaluated by double disk synergy test and spectrophotometric detection of imipenem hydrolysis, respectively. ESBL and carbapenemase encoding genes were surveyed by Polymerase chain reaction (PCR). Differences among groups were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests.

RESULTS: GNB were isolated from 36.2% of all subgingival biofilm samples, with a significantly greater prevalence and species diversity (P < 0.001) in patients with periodontitis (45.9%) compared with individuals with PH (24.1%) and gingivitis (22.9%). Pseudomonas aeruginosa (27.5%), Enterobacter cloacae (16.8%), and Enterobacter asburiae (10.7%) were the most predominant species. Resistance/reduced sensitivity to at least 1 antimicrobial was detected in 60% of the strains, but only 4.6% were multidrug resistant. Serratia marcescens, E. cloacae, and Enterobacter kobei presented high rates of intrinsic resistance (>40%) to amoxicillin-clavulanate and first/second-generations of cephalosporins. One strain of Klebsiella pneumoniae isolated from periodontitis was resistant to imipenem, but no ESBL encoding genes or ESBL phenotype was detected.

CONCLUSION: High prevalence and diversity of GNB, with low susceptibility to β-lactams are observed in the subgingival microbiota associated with periodontitis.}, } @article {pmid33955439, year = {2021}, author = {Wang, L and Peng, R and Liu, X and Heng, C and Miao, Y and Wang, W and Carrier, A and Oakes, K and Zhang, X}, title = {Nitrite-enhanced copper-based Fenton reactions for biofilm removal.}, journal = {Chemical communications (Cambridge, England)}, volume = {57}, number = {45}, pages = {5514-5517}, doi = {10.1039/d1cc00374g}, pmid = {33955439}, issn = {1364-548X}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/drug effects ; Copper/*chemistry/pharmacology ; Drug Therapy, Combination ; Escherichia coli ; Free Radicals/chemistry ; Hydrogen Peroxide/chemistry ; Metal Nanoparticles/*chemistry ; Nitrites/*chemistry/pharmacology ; Staphylococcus aureus ; Surface Properties ; }, abstract = {Unwanted biofilms present challenges for many industries. Herein an innovative biofilm removal technology was developed based on nitrite-accelerated Fenton chemistry, where both dissolved Cu ions and nano-CuO surfaces efficiently generate reactive nitrogen species as disinfectants. This simple, efficient, and cost-effective approach for biofilm removal generates important insights into Fenton chemistry, a fundamental mechanism in nature, considering the ubiquity of copper, hydrogen peroxide, and nitrite in the environment, biological systems, and various industrial processes.}, } @article {pmid33951583, year = {2021}, author = {de Vries, HJ and Kleibusch, E and Hermes, GDA and van den Brink, P and Plugge, CM}, title = {Biofouling control: the impact of biofilm dispersal and membrane flushing.}, journal = {Water research}, volume = {198}, number = {}, pages = {117163}, doi = {10.1016/j.watres.2021.117163}, pmid = {33951583}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Biomass ; Membranes, Artificial ; *Water Purification ; }, abstract = {Pure culture studies have shown that biofilm dispersal can be triggered if the nutrient supply is discontinued by stopping the flow. Stimulating biofilm dispersal in this manner would provide a sustainable manner to control unwanted biofilm growth in industrial settings, for instance on synthetic membranes used to purify water. The response of multispecies biofilms to nutrient limitation has not been thoroughly studied. To assess biomass dispersal during nutrient limitation it is common practise to flush the biofilm after a stop-period. Hence, flow-stop-induced biomass removal could occur as a response to nutrient limitation followed by mechanical removal due to biofilm flushing (e.g. biofilm detachment). Here, we investigated the feasibility to reduce membrane biofouling by stopping the flow and flushing the membrane. Using a membrane fouling simulator, biomass removal from synthetic membranes after different stop-periods was determined, as well as biomass removal at different cross flow velocities. Biomass removal from membrane surfaces depended on the nutrient limiting period and on the flow velocity during the biofilm flush. When flushed at a low flow velocity (0.1 m.s[-1]), the duration of the stop-period had a large effect on the biomass removal rate, but when the flow velocity was increased to 0.2 m.s[-1], the length of the stop period became less considerable. The flow velocity during membrane flushing has an effect on the bacterial community that colonized the membranes afterwards. Repetition of the stop-period and biofilm flushing after three repetitive biofouling cycles led to a stable bacterial community. The increase in bacterial community stability coincided with a decrease in cleaning effectivity to restore membrane performance. This shows that membrane cleaning comes at the costs of a more stable bacterial community that is increasingly difficult to remove.}, } @article {pmid33951320, year = {2021}, author = {Choi, H and Schulte, A and Müller, M and Park, M and Jo, S and Schönherr, H}, title = {Drug Release from Thermo-Responsive Polymer Brush Coatings to Control Bacterial Colonization and Biofilm Growth on Titanium Implants.}, journal = {Advanced healthcare materials}, volume = {10}, number = {11}, pages = {e2100069}, doi = {10.1002/adhm.202100069}, pmid = {33951320}, issn = {2192-2659}, mesh = {Biofilms ; Drug Liberation ; Methacrylates ; *Polymers ; *Titanium ; }, abstract = {Despite decades of biomedical advances, the colonization of implant devices with bacterial biofilms is still a leading cause of implant failure. Clearly, new strategies and materials that suppress both initial and later stage bacterial colonization are required in this context. Ideal would be the implementation of a bactericidal functionality in the implants that is temporally and spatially triggered in an autonomous fashion at the infection site. Herein, the fabrication and validation of functional titanium-based implants with triggered antibiotic release function afforded via an intelligent polymer coating is reported. In particular, thermo-responsive poly(di(ethylene glycol) methyl ether methacrylate) (PDEGMA) brushes on titanium implants synthesized via a surface-initiated atom transfer radical polymerization with activators regenerated through the electron transfer technique (ARGET ATRP) allows for a controlled and thermally triggered release of the antibiotic levofloxacin at the wound site. Antibiotic loaded brushes are investigated as a function of thickness, loading capacity for antibiotics, and temperature. At temperatures of the infection site >37 °C the lower critical solution temperature behavior of the brushes afforded the triggered release. Hence, in addition to the known antifouling effects, the PDEGMA coating ensured enhanced bactericidal effects, as demonstrated in initial in vivo tests with rodents infected with Staphylococcus aureus.}, } @article {pmid33950839, year = {2021}, author = {Childers, C and Edsall, C and Gannon, J and Whittington, AR and Muelenaer, AA and Rao, J and Vlaisavljevich, E}, title = {Focused Ultrasound Biofilm Ablation: Investigation of Histotripsy for the Treatment of Catheter-Associated Urinary Tract Infections (CAUTIs).}, journal = {IEEE transactions on ultrasonics, ferroelectrics, and frequency control}, volume = {68}, number = {9}, pages = {2965-2980}, doi = {10.1109/TUFFC.2021.3077704}, pmid = {33950839}, issn = {1525-8955}, mesh = {Biofilms ; Humans ; Pseudomonas aeruginosa ; Urinary Catheters ; *Urinary Tract Infections/etiology ; }, abstract = {Urinary catheters often become contaminated with biofilms, resulting in catheter-associated urinary tract infections (CAUTIs) that adversely affect patient outcomes. Histotripsy is a noninvasive focused ultrasound therapy previously developed for the noninvasive ablation of cancerous tumors and soft tissues. Histotripsy has also previously shown the ability to treat biofilms on glass slides and surgical meshes. Here, we investigate the potential of histotripsy for the treatment of CAUTIs for the first time in vitro. Clinically relevant catheter materials (Tygon, Silicone, and latex catheter mimics) and commonly used clinical catheters were tested to determine the feasibility of producing luminal histotripsy bubble clouds. A Pseudomonas aeruginosa (strain PA14) biofilm model was developed and tested to produce luminal biofilms in an in vitro Tygon catheter mimic. This model was treated with histotripsy to determine the ability to remove a luminal biofilm. Finally, the bactericidal effects of histotripsy were tested by treating PA14 suspended inside the Tygon catheter mimic. Results showed that histotripsy produced precise luminal cavitation within all tested catheter mimics and clinical catheters. Histotripsy treatment of a PA14 biofilm with histotripsy reduced luminal biofilm OD590 signal down to background levels. Further, the treatment of suspended PA14 in Luria-Bertani (LB) showed a 3.45 ± 0.11 log10 reduction in CFU/mL after six histotripsy scans across the catheter mimics. Overall, the results of this study demonstrate the potential of histotripsy to provide a new modality for removing bacterial biofilms from catheter-based medical devices and suggest that additional work is warranted to investigate histotripsy for the treatment of CAUTIs and other biomaterial-associated infections.}, } @article {pmid33948084, year = {2021}, author = {Yu, J and Yi, L and Guo, R and Guo, J and Yang, H and Huang, C}, title = {The Stability of Dentin Surface Biobarrier Consisting of Mesoporous Delivery System on Dentinal Tubule Occlusion and Streptococcus Mutans Biofilm Inhibition.}, journal = {International journal of nanomedicine}, volume = {16}, number = {}, pages = {3041-3057}, pmid = {33948084}, issn = {1178-2013}, mesh = {Acids ; Adsorption ; Biofilms/drug effects/*growth & development ; Calcium/analysis ; Caseins/pharmacology ; Catechin/analogs & derivatives/chemistry/pharmacology ; Cell Death/drug effects ; Colony Count, Microbial ; Dental Pulp/cytology ; Dentin/*chemistry ; Humans ; Nanoparticles/chemistry/ultrastructure ; Nitrogen/chemistry ; Permeability ; Phosphorus/analysis ; Porosity ; Silicon Dioxide/chemistry ; Streptococcus mutans/*physiology/ultrastructure ; }, abstract = {BACKGROUND: The dentin exposure always leads to dentin hypersensitivity and/or caries. Given the dentin's tubular structure and low mineralization degree, reestablishing an effective biobarrier to stably protect dentin remains significantly challenging. This study reports a versatile dentin surface biobarrier consisting of a mesoporous silica-based epigallocatechin-3-gallate (EGCG)/nanohydroxyapatite delivery system and evaluates its stability on the dentinal tubule occlusion and the Streptococcus mutans (S. mutans) biofilm inhibition.

MATERIALS AND METHODS: The mesoporous delivery system was fabricated and characterized. Sensitive dentin discs were prepared and randomly allocated to three groups: 1, control group; 2, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group; and 3, the mesoporous delivery system group. The dentin permeability, dentinal tubule occlusion, acid and abrasion resistance, and S. mutans biofilm inhibition were determined for 1 week and 1 month. The in vitro release profiles of EGCG, Ca, and P were also monitored.

RESULTS: The mesoporous delivery system held the ability to sustainably release EGCG, Ca, and P and could persistently occlude dentinal tubules with acid and abrasion resistance, reduce the dentin permeability, and inhibit the S. mutans biofilm formation for up to 1 month compared with the two other groups. The system provided prolonged stability to combat oral adverse challenges and served as an effective surface biobarrier to protect the exposed dentin.

CONCLUSION: The establishment of the dentin surface biobarrier consisting of a mesoporous delivery system indicates a promising strategy for the prevention and the management of dentin hypersensitivity and caries after enamel loss.}, } @article {pmid33947280, year = {2021}, author = {Jiang, L and Zheng, R and Sun, Q and Li, C}, title = {Isolation, characterization, and application of Salmonella paratyphi phage KM16 against Salmonella paratyphi biofilm.}, journal = {Biofouling}, volume = {37}, number = {3}, pages = {276-288}, doi = {10.1080/08927014.2021.1900130}, pmid = {33947280}, issn = {1029-2454}, mesh = {*Bacteriophages/genetics ; Biofilms ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Salmonella/genetics ; *Salmonella Phages/genetics ; Salmonella paratyphi A ; }, abstract = {Salmonella biofilm prevention and control is of great importance. This study, investigated the use of the isolated phage KM16 belonging to the family Myoviridae in the order Caudovirales. The phage genome size was 170,126 bp. Almost all phages were adsorbed to the host within 20 min. KM16 had a latent period of 70 min followed by a rise period of 40 min. Phage KM16 had the ability to lytically infect 10 out of the 12 clinical strains of S. paratyphi tested. Phylogenetic analysis indicated that the S. paratyphi 16S rRNA, crispr 1 and fimA genes correlated with the lytic spectrum of phage KM16. The lytic spectrum of phage KM16 correlated with Salmonella pili (fimA), and Salmonella pili were the recognition site for phage adsorption to the host. Phage KM16 (MOI = 0.1) had a better anti-biofilm effect than kanamycin sulfate (10 ug ml[-1]) in high-concentration Salmonella cultures.}, } @article {pmid33947279, year = {2021}, author = {Fu, Y and Liu, W and Liu, M and Zhang, J and Yang, M and Wang, T and Qian, W}, title = {In vitro anti-biofilm efficacy of sanguinarine against carbapenem-resistant Serratia marcescens.}, journal = {Biofouling}, volume = {37}, number = {3}, pages = {341-351}, doi = {10.1080/08927014.2021.1919649}, pmid = {33947279}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Benzophenanthridines/pharmacology ; *Biofilms ; Carbapenems ; Isoquinolines ; Microbial Sensitivity Tests ; *Serratia marcescens ; }, abstract = {Sanguinarine, a plant-derived benzophenanthridine alkaloid, was studied in terms of its anti-biofilm effects against carbapenem-resistant Serratia marcescens (CRSM). Minimum inhibitory concentrations (MICs) and cell membrane integrity were measured to investigate the antimicrobial mechanism of sanguinarine. Additionally, the extent of biofilm formation by CRSM exposed to sanguinarine was measured by crystal violet staining and visualized via field emission scanning electron microscopy and confocal laser scanning microscopy. Sanguinarine displayed moderate activity against CRSM, with a MIC90 of 32 μg ml[-1]. Moreover, cell membrane integrity was severely disrupted by sanguinarine at 64 μg ml[-1], and biofilm formation was sharply inhibited at 32 μg ml[-1]. The minimum biofilm eradication concentration was 512 μg ml[-1] against mature CRSM biofilms. The overall results suggest that sanguinarine is a potential anti-biofilm agent that can be explored to treat CRSM infections.}, } @article {pmid33946614, year = {2021}, author = {Ryu, S and Shin, M and Yun, B and Lee, W and Choi, H and Kang, M and Oh, S and Kim, Y}, title = {Bacterial Quality, Prevalence of Pathogens, and Molecular Characterization of Biofilm-Producing Staphylococcus aureus from Korean Dairy Farm Environments.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {5}, pages = {}, pmid = {33946614}, issn = {2076-2615}, support = {PJ0158652021//Rural Development Administration/ ; MIFI2020KMBB01//Ministry of Agriculture, Food and Rural Affairs/ ; }, abstract = {Raw milk acts as a mediator of major foodborne pathogenic bacterial infections. However, the sources of pathogens that contaminate milk are often unclear. This study assessed the prevalence of sanitary quality-indicating bacteria (total aerobic bacteria, psychrotrophic bacteria, coliform, and yeast/molds), including seven foodborne pathogens, in a dairy farm environment and processing plant in Korea. The microbiological analysis showed that a few sites, such as vat bottoms, room floors, drain holes, and niches, showed high microbial loads in most dairy farms. Based on quantitative microbial tests, Bacillus cereus was detected in three farms and Staphylococcus aureus was detected in only one farm. Among them, S. aureus JDFM SA01 isolated from a milk filter showed strong biofilm formation and toxicity to the host Caenorhabditis elegans. Subsequently, RNA-seq was performed to characterize the biofilm formation ability of S. aureus JDFM SA01. In biofilms, the significant upregulation of genes encoding microbial surface components and recognizing adhesive matrix molecules promotes adhesion might explain the increased viability and biomass of biofilms. This study provided insight into the prevalence of pathogenic bacteria and microbial contamination levels across dairy farms.}, } @article {pmid33946431, year = {2021}, author = {Greer, HM and Overton, K and Ferguson, MA and Spain, EM and Darling, LEO and Núñez, ME and Volle, CB}, title = {Extracellular Polymeric Substance Protects Some Cells in an Escherichia coli Biofilm from the Biomechanical Consequences of Treatment with Magainin 2.}, journal = {Microorganisms}, volume = {9}, number = {5}, pages = {}, pmid = {33946431}, issn = {2076-2607}, support = {R15 GM120665/GM/NIGMS NIH HHS/United States ; DBI1528288//National Science Foundation/ ; }, abstract = {Bacterial biofilms have long been recognized as a source of persistent infections and industrial contamination with their intransigence generally attributed to their protective layer of extracellular polymeric substances (EPS). EPS, consisting of secreted nucleic acids, proteins, and polysaccharides, make it difficult to fully eliminate biofilms by conventional chemical or physical means. Since most bacteria are capable of forming biofilms, understanding how biofilms respond to new antibiotic compounds and components of the immune system has important ramifications. Antimicrobial peptides (AMPs) are both potential novel antibiotic compounds and part of the immune response in many different organisms. Here, we use atomic force microscopy to investigate the biomechanical changes that occur in individual cells when a biofilm is exposed to the AMP magainin 2 (MAG2), which acts by permeabilizing bacterial membranes. While MAG2 is able to prevent biofilm initiation, cells in an established biofilm can withstand exposure to high concentrations of MAG2. Treated cells in the biofilm are classified into two distinct populations after treatment: one population of cells is indistinguishable from untreated cells, maintaining cellular turgor pressure and a smooth outer surface, and the second population of cells are softer than untreated cells and have a rough outer surface after treatment. Notably, the latter population is similar to planktonic cells treated with MAG2. The EPS likely reduces the local MAG2 concentration around the stiffer cells since once the EPS was enzymatically removed, all cells became softer and had rough outer surfaces. Thus, while MAG2 appears to have the same mechanism of action in biofilm cells as in planktonic ones, MAG2 cannot eradicate a biofilm unless coupled with the removal of the EPS.}, } @article {pmid33946290, year = {2021}, author = {El Haj, C and Lichtenberg, M and Nielsen, KL and Bjarnsholt, T and Jensen, PØ}, title = {Catalase Protects Biofilm of Staphylococcus aureus against Daptomycin Activity.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {33946290}, issn = {2079-6382}, abstract = {Daptomycin is recommended for the treatment of Staphylococcus aureus infections due to its bactericidal activity. However, its mechanism of action is poorly understood. The involvement of reactive oxygen species (ROS) in the bactericidal activity of daptomycin has been proved against planktonic S. aureus, but not against the biofilm of S. aureus. Therefore, we evaluated if ROS contributes to the effect of daptomycin against biofilm of S. aureus. Biofilms of wild type, catalase deficient and daptomycin-resistant S. aureus strains were grown in microtiter-plates. After three days, the biofilms were exposed to daptomycin with or without thiourea in the presence of a ROS indicator. After overnight incubation, the amount of ROS and the percentage of surviving bacteria were determined. The bacterial survival was higher and the amount of ROS was lower in the wild type than in the catalase deficient biofilm, demonstrating a protective effect of catalase against daptomycin. The induction of cytotoxic ROS formation by daptomycin was verified by the addition of thiourea, which reduced the amount of ROS and protected the wild type biofilm against high concentrations of daptomycin. Accordingly, only the highest concentration of daptomycin reduced the bacterial survival and increased the ROS formation in the resistant biofilm. In conclusion, daptomycin induced the production of cytotoxic levels of endogenous ROS in S. aureus biofilm and the presence of catalase protected the biofilm against the lethality of the induced ROS.}, } @article {pmid33945694, year = {2021}, author = {Kroning, IS and Ramires, T and Haubert, L and Rizzi, C and Fernandes, MDS and Lopes, GV and Dellagostin, OA and Silva, WPD}, title = {Biofilm formation of Staphylococcus aureus from milk and expression of the adhesion genes ebpS and cna at different temperatures.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {9}, pages = {677-685}, doi = {10.1139/cjm-2021-0065}, pmid = {33945694}, issn = {1480-3275}, mesh = {Animals ; Biofilms ; Humans ; Milk ; *Staphylococcal Infections ; *Staphylococcus aureus/genetics ; Temperature ; }, abstract = {This study investigated the ability of Staphylococcus aureus isolates from milk to form biofilm, through detection of adhesion genes, investigating exopolysaccharide (EPS) production and biofilm formation on polystyrene (PS) and stainless steel (SS) surfaces, and by quantifying the expression of ebpS and cna genes under different temperatures and culture media. Among the 31 isolates, the adhesion genes ebpS and cna were found in 81% and 61% of the isolates, respectively. The screening tests for phenotype revealed that 58% of the isolates were EPS producers, and 45% showed the ability to produce biofilm on PS. Nine of the 31 isolates were selected to verify their ability to form biofilm on SS, of which 3 were non-biofilm producers, 3 were poor biofilm producers, and 3 were moderate biofilm producers. However, all nine isolates produced biofilm on SS, regardless of their phenotypic profile on PS. Reverse-transcriptase quantitative PCR (RT-qPCR) revealed no variation in the expression levels of ebpS and cna genes at different temperatures, except for isolate S24 at 10 °C, for both genes tested. Moreover, RT-qPCR assays revealed that the expression levels of the adhesion genes ebpS and cna are isolate- and temperature-dependent; however, they are independent of the phenotypic biofilm-formation profile.}, } @article {pmid33944621, year = {2022}, author = {Mb, CS and Ja, MF and Ja, SB and R, VR and Jr, IR and J, MU and C, C and N, CC}, title = {Structural variations on Salmonella biofilm by exposition to river water.}, journal = {International journal of environmental health research}, volume = {32}, number = {7}, pages = {1626-1643}, doi = {10.1080/09603123.2021.1901863}, pmid = {33944621}, issn = {1369-1619}, mesh = {Biofilms ; *Rivers ; *Salmonella ; Sugars ; Water ; }, abstract = {Biofilm formation, as adapting strategies, is the result of stressful conditions that Salmonella faces in hostile environments like surface water. We evaluated river water effect on Salmonella biofilm formation ability in terms of physical, morphological characteristics and chemical composition. A new morphotype SPAM (soft, pink and mucoid) was detected in Oranienburg strains S-76 and S-347 (environmental and clinical isolate). Oranienburg serotypes showed very marked behavior in adherence, pellicle liquid-air and resistance, being Oranienburg S-76 the strongest biofilm producer. All strains when exposed to river water presented an overlapping mucoid layer in the morphotype and increased their motility except Oranienburg S-347. The most motile was Typhimurium (control) and the least Infantis S-304 (clinical isolate). Mannose, glucose, galactose and ribose were the main biofilm sugar components; type and concentration of sugar suggest a morphotype/serotype dependent pattern. Strong morphotypes expressed in this study may be an effective protective strategy for Salmonella in hostile environments.}, } @article {pmid33938347, year = {2021}, author = {Lin, Y and Chen, J and Zhou, X and Li, Y}, title = {Inhibition of Streptococcus mutans biofilm formation by strategies targeting the metabolism of exopolysaccharides.}, journal = {Critical reviews in microbiology}, volume = {47}, number = {5}, pages = {667-677}, doi = {10.1080/1040841X.2021.1915959}, pmid = {33938347}, issn = {1549-7828}, mesh = {Animals ; Biofilms/*growth & development ; Dental Caries/microbiology/*prevention & control ; Gene Expression Regulation, Bacterial ; Humans ; Polysaccharides, Bacterial/*metabolism ; Prebiotics ; Probiotics ; Streptococcus mutans/drug effects/genetics/pathogenicity/*physiology ; Virulence ; Virulence Factors/*metabolism ; }, abstract = {Dental caries is one of the most prevalent and costly biofilm-associated infectious diseases affecting most of the world's population. In particular, dental caries is driven by dysbiosis of the dental biofilm adherent to the enamel surface. Specific types of acid-producing bacteria, especially Streptococcus mutans, colonize the dental surface and cause damage to the hard tooth structure in the presence of fermentable carbohydrates. Streptococcus mutans has been established as the major cariogenic pathogen responsible for human dental caries, with a high ability to form biofilms. The exopolysaccharide (EPS) matrix, mainly contributed by S. mutans, has been considered as a virulence determinant of cariogenic biofilm. As EPS is an important virulence factor, targeting EPS metabolism could be useful in preventing cariogenic biofilm formation. This review summarizes plausible strategies targeting S. mutans biofilms by degrading EPS structure, inhibiting EPS production, and disturbing the EPS metabolism-related gene expression and regulatory systems.}, } @article {pmid33937714, year = {2020}, author = {Burbank, KM and Schauer, SG and De Lorenzo, RA and Wenke, JC}, title = {Early application of topical antibiotic powder in open-fracture wounds: A strategy to prevent biofilm formation and infections.}, journal = {OTA international : the open access journal of orthopaedic trauma}, volume = {3}, number = {4}, pages = {e091}, pmid = {33937714}, issn = {2574-2167}, abstract = {Despite meticulous surgical care and systemic antibiotics, open fracture wounds have high rates of infection leading to increased morbidity. To reduce infection rates, orthopaedic surgeons may administer local antibiotics using various carriers that may be ineffective due to poor antibiotic release from carriers, subsequent surgery to remove nondegradable carriers, and mismatch between release kinetics and material degradation. Biofilms form rapidly as bacteria that are within the wound multiply quickly and transform from the antibiotic-susceptible planktonic phenotype to the antibiotic-tolerant biofilm phenotype. This tolerance to antibiotics can occur within hours. Currently, local antibiotics are placed in the wounds using a carrier such as polymethylmethacrylate beads; however, this occurs after surgical debridement that can be hours to even a day after initial injury allowing bacteria enough time to form a biofilm that makes the antibiotic containing polymethylmethacrylate beads less effective. In contrast, emerging practices in elective surgical procedures, such as spine fusion, place antibiotic powder (e.g. vancomycin) in the wound at the time of closure. This has been shown to be extremely effective, presumably because of the very small-time period between potential contamination and local antibiotic application. There is evidence that suggests that the ineffectiveness of local antibiotic use in open fractures is primarily due to the delay in application of local antibiotics from the time of injury and propose a concept of topical antibiotic powder application in the prehospital or emergency department setting.}, } @article {pmid33936852, year = {2021}, author = {Caballero-Prado, CJ and Merino-Mascorro, JA and Heredia, N and Dávila-Aviña, J and García, S}, title = {Eugenol, citral, and hexanal, alone or in combination with heat, affect viability, biofilm formation, and swarming on Shiga-toxin-producing Escherichia coli.}, journal = {Food science and biotechnology}, volume = {30}, number = {4}, pages = {599-607}, pmid = {33936852}, issn = {2092-6456}, abstract = {Shiga-toxin-producing Escherichia coli strains are pathogenic for humans and cause mild to severe illnesses. In this study, the antimicrobial effect of citral, eugenol, and hexanal in combination with heat shock (HS) was evaluated in terms of the growth, biofilm formation, swarming, and expression of virulence genes of STEC serotypes (O157:H7, O103, O111, and O26). Eugenol was the most effective compound against the growth of E. coli strains (MBC = 0.58 to 0.73 mg/mL), followed by citral (MBC = 0.86 to 1.26 mg/mL) and hexanal (MBC = 2.24 to 2.52 mg/mL). Biofilm formation and swarming motility have great variability between STEC strains. Natural compounds-alone or combined with HS-inhibited biofilm formation; however, swarming motility was induced by most treatments. The expression of the studied genes during biofilm formation and swarming under natural antimicrobials was affected but not in a uniform pattern. These treatments could be used to control contamination of STEC and inhibit biofilm formation.}, } @article {pmid33935982, year = {2021}, author = {Yao, Y and Rao, S and Habimana, O}, title = {Active Microbiome Structure and Functional Analyses of Freshwater Benthic Biofilm Samples Influenced by RNA Extraction Methods.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {588025}, pmid = {33935982}, issn = {1664-302X}, abstract = {Advances in high-throughput sequencing technologies have enabled extensive studies of freshwater biofilms and significant breakthroughs in biofilm meta-omics. To date, however, no standardized protocols have been developed for the effective isolation of RNA from freshwater benthic biofilms. In this study, we compared column-based kit RNA extraction with five RNAzol-based extractions, differentiated by various protocol modifications. The RNA products were then evaluated to determine their integrity, purity and yield and were subjected to meta-transcriptomic sequencing and analysis. Significant discrepancies in the relative abundance of active communities and structures of eukaryotic, bacterial, archaebacterial, and viral communities were observed as direct outcomes of the tested RNA extraction methods. The column isolation-based group was characterized by the highest relative abundance of Archaea and Eukaryota, while the organic isolation-based groups commonly had the highest relative abundances of Prokaryota (bacteria). Kit extraction methods provided the best outcomes in terms of high-quality RNA yield and integrity. However, these methods were deemed questionable for studies of active bacterial communities and may contribute a significant degree of bias to the interpretation of downstream meta-transcriptomic analyses.}, } @article {pmid33934665, year = {2021}, author = {Qian, W and Wang, W and Zhang, J and Liu, M and Fu, Y and Li, M and Jin, J and Cui, W and Wang, C}, title = {Equivalent effect of extracellular proteins and polysaccharides on biofilm formation by clinical isolates of Staphylococcus lugdunensis.}, journal = {Biofouling}, volume = {37}, number = {3}, pages = {327-340}, doi = {10.1080/08927014.2021.1914021}, pmid = {33934665}, issn = {1029-2454}, mesh = {Biofilms ; DNA, Bacterial ; Polysaccharides ; *Staphylococcus lugdunensis ; }, abstract = {Biofilm formation by Staphylococcus lugdunensis involves formation of an extracellular matrix; however, the identity of the constituents responsible for the structure of biofilms fabricated by different clinical strains is largely unclear. Here, biofilms produced by 24 clinical isolates of S. lugdunensis were characterized. The optimal medium for S. lugdunensis was selected, and the biofilm-forming capacity was assessed. Extracelullar polymeric substances (EPS) contributing to biofilm robustness were determined by evaluating the susceptibility of biofilms to EPS-degrading agents using field emission scanning electron microscopy and confocal laser scanning microscopy. Biofilm formation by the clinical isolates of S. lugdunensis was augmented by glucose supplementation. Further, extracellular DNA (eDNA), proteins, and polysaccharides were present in the 24 clinical isolates. Proteins and polysaccharides were the most common components within the S. lugdunensis biofilms, whereas the eDNA content was marginal in biofilm formation. Therefore, proteins and polysaccharides within biofilms may be used as the primary targets for developing eradication strategies to prevent S. lugdunensis biofilm formation.}, } @article {pmid33934664, year = {2021}, author = {O'Donnell, JA and Wu, M and Cochrane, NH and Belay, E and Myntti, MF and James, GA and Ryan, SP and Seyler, TM}, title = {Efficacy of common antiseptic solutions against clinically relevant microorganisms in biofilm.}, journal = {The bone & joint journal}, volume = {103-B}, number = {5}, pages = {908-915}, doi = {10.1302/0301-620X.103B5.BJJ-2020-1245.R2}, pmid = {33934664}, issn = {2049-4408}, mesh = {Acetic Acid/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; *Arthroplasty, Replacement ; Benzalkonium Compounds/pharmacology ; Betaine/pharmacology ; Biguanides/pharmacology ; Biofilms/*drug effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Hydrogen Peroxide/pharmacology ; In Vitro Techniques ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Povidone-Iodine/pharmacology ; Propionibacteriaceae/drug effects ; Prosthesis-Related Infections/*microbiology/*prevention & control ; Pseudomonas aeruginosa/drug effects ; Sodium Hypochlorite/pharmacology ; Staphylococcus epidermidis/drug effects ; }, abstract = {AIMS: Periprosthetic joint infections (PJIs) are among the most devastating complications after joint arthroplasty. There is limited evidence on the efficacy of different antiseptic solutions on reducing biofilm burden. The purpose of the present study was to test the efficacy of different antiseptic solutions against clinically relevant microorganisms in biofilm.

METHODS: We conducted an in vitro study examining the efficacy of several antiseptic solutions against clinically relevant microorganisms. We tested antiseptic irrigants against nascent (four-hour) and mature (three-day) single-species biofilm created in vitro using a drip-flow reactor model.

RESULTS: With regard to irrigant efficacy against biofilms, Povidone-iodine treatment resulted in greater reductions in nascent MRSA biofilms (logarithmic reduction (LR) = 3.12; p < 0.001) compared to other solutions. Bactisure treatment had the greatest reduction of mature Pseudomonas aeruginosa biofilms (LR = 1.94; p = 0.032) and a larger reduction than Vashe or Irrisept for mature Staphylococcus epidermidis biofilms (LR = 2.12; p = 0.025). Pooled data for all biofilms tested resulted in Bactisure and Povidone-iodine with significantly greater reductions compared to Vashe, Prontosan, and Irrisept solutions (p < 0.001).

CONCLUSION: Treatment failure in PJI is often due to failure to clear the biofilm; antiseptics are often used as an adjunct to biofilm clearance. We tested irrigants against clinically relevant microorganisms in biofilm in vitro and showed significant differences in efficacy among the different solutions. Further clinical outcome data is necessary to determine whether these solutions can impact PJI outcome in vivo. Cite this article: Bone Joint J 2021;103-B(5):908-915.}, } @article {pmid33932598, year = {2021}, author = {Kaur, B and Naveen Kumar, BT and Tyagi, A and Admane Holeyappa, S and Singh, NK}, title = {Identification of novel vaccine candidates in the whole-cell Aeromonas hydrophila biofilm vaccine through reverse vaccinology approach.}, journal = {Fish & shellfish immunology}, volume = {114}, number = {}, pages = {132-141}, doi = {10.1016/j.fsi.2021.04.019}, pmid = {33932598}, issn = {1095-9947}, mesh = {Aeromonas hydrophila/immunology/*physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Bacterial Vaccines ; Biofilms/*growth & development ; Chromatography, Liquid/methods ; *Cyprinidae ; Epitopes, B-Lymphocyte ; Fish Diseases/microbiology/*prevention & control ; Nanotechnology ; Tandem Mass Spectrometry ; Vaccinology/methods ; }, abstract = {Biofilm vaccine has been recognised as one of the successful strategy to reduce the Aeromonas hydrophila infection in fish. But, the vaccine contains the protective and non-protective proteins, which may lead to show altered heterologous adaptive immunity response. Moreover, cross protection and effectiveness of previously developed biofilm vaccine was not tested against different geographical A. hydrophila isolates. Therefore, in the present study, whole-cell A. hydrophila biofilm vaccine was evaluated in rohu, vaccinated group showed increased antibody titer and protection against the different geographical A. hydrophila isolates namely KAH1 and AAH2 with 78.9% and 84.2% relative percentage survival, respectively. In addition, by using the immune sera of biofilm vaccinated group, a total of six protective proteins were detected using western blot assay. Further, the same proteins were identified by nano LC-MS/MS method, a total of fourteen candidate proteins showing the immunogenic property including highly expressed OMP's tolC, bamA, lamb, AH4AK4_2542, AHGSH82_029580 were identified as potential vaccine candidates. The STRING analysis revealed that, top candidate proteins identified may potentially interact with other intracellular proteins; involved in ribosomal and (tricarboxylic acid) TCA pathway. Importantly, all the selected vaccine candidate proteins contain the B-cell epitope region. Finally, the present study concludes that, whole-cell A. hydrophila biofilm vaccine able to protect the fish against the different geographical A. hydrophila isolates. Further, through reverse vaccinology approach, a total of fourteen proteins were identified as potential vaccine candidates against A. hydrophila pathogen.}, } @article {pmid33932554, year = {2021}, author = {Ionescu, AC and Brambilla, E and Sighinolfi, MC and Mattina, R}, title = {A new urinary catheter design reduces in-vitro biofilm formation by influencing hydrodynamics.}, journal = {The Journal of hospital infection}, volume = {114}, number = {}, pages = {153-162}, doi = {10.1016/j.jhin.2021.01.033}, pmid = {33932554}, issn = {1532-2939}, mesh = {Biofilms ; Humans ; *Hydrodynamics ; Urinary Catheterization/adverse effects ; Urinary Catheters ; *Urinary Tract Infections ; }, abstract = {AIM: To evaluate the performance of a new catheter design based on different hydrodynamics aiming to reduce the development of biofilm, and compare it with a conventional Foley catheter (FC).

METHODS: The new proposed design (NPD) catheter is a modification of the FC, based on asymmetric positioning of the balloon and additional drainage holes allowing continuous urine drainage and complete voiding of the bladder. A first experiment was undertaken to assess drainage capability, and a second experiment was performed using a bioreactor with a set-up simulating the bladder and using the test catheter as a flow-through system. The biofilm formation of five bacterial species associated with catheter-associated urinary tract infection (CAUTI) was determined after 24 h of incubation using an MTT assay. Morphological evaluation was performed using scanning electron microscopy. In-vitro determination of residual fluid, and quantitative and morphological data on biofilm formation on the intravesical and intraluminal parts of the tested catheters were assessed.

RESULTS: Residual fluid was significantly higher in the FC (5.60 ± 0.43 mL) compared with the NPD catheter (0.2 ± 0.03 mL). The NPD catheter showed significantly less biofilm formation (P<0.0001) than the FC. Catheter design had a variable effect on biofilm formation depending on the bacterial strain tested. There was significantly less intraluminal biomass compared with intravesical biomass in both catheters (P<0.0001). Multi-layered biofilms that covered the FC surfaces completely were seen for all tested strains, while the NPD catheter surfaces showed reduced biofilm formation.

CONCLUSIONS: Modifications of the hydrodynamic characteristics of a catheter can significantly reduce bacterial colonization. Integrated design approaches combining chemical, mechanical and topographical elements can help to reduce the occurrence of CAUTI.}, } @article {pmid33932545, year = {2021}, author = {Al-Shamiri, MM and Zhang, S and Mi, P and Liu, Y and Xun, M and Yang, E and Ai, L and Han, L and Chen, Y}, title = {Phenotypic and genotypic characteristics of Acinetobacter baumannii enrolled in the relationship among antibiotic resistance, biofilm formation and motility.}, journal = {Microbial pathogenesis}, volume = {155}, number = {}, pages = {104922}, doi = {10.1016/j.micpath.2021.104922}, pmid = {33932545}, issn = {1096-1208}, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; }, abstract = {Acinetobacter baumannii is an important pathogen in clinical. The factors of biofilm formation, antibiotic resistance and motility contribute great to A. baumannii in persisting in stressed environment, and further leads to nosocomial infections. 70 A. baumannii clinical isolates were investigated for their clinical characteristics of infection. Among the tested strains, 54 (77.1%) isolates were obtained from ICUs, with the frequency of multidrug-resistance (MDR) at 55.7%, and that of extensively drug-resistance (XDR) at 31.4%. 97.1% of the clinical isolates could form biofilms, in which 4.3% possessed weak biofilm formation ability, while 41.4% and 51.4% were moderate and strong biofilm producers, respectively. A strong correlation between antibiotic resistance and biofilm formation ability was found that all the resistant strains could form biofilms, with the majority in moderate and strong levels, but 2.9% sensitive isolates had no such ability. However, the sensitive strains that could produce biofilms showed stronger biofilm formation capacity in the early stage before 24 h compared to the resistant isolates, though they became weaker afterwards. 24 biofilm-related genes and two blaOXA genes were found in both biofilm-forming and non-biofilm-forming strains, but with higher prevalence in the strains that could produce biofilms. No correlation was detected between twitching motility with antibiotic susceptibility or biofilm formation. These results raised a viewpoint that examining timepoint is a key factor for determining the biofilm formation ability, and further highlighted the importance of the appropriate surveillance and control measures in preventing the emergence and transmission of MDR and XDR A. baumannii.}, } @article {pmid33930475, year = {2021}, author = {Silva, NBS and Alves, PGV and de Andrade Marques, L and Silva, SF and de Oliveira Faria, G and de Araújo, LB and Pedroso, RDS and Penatti, MPA and de Paula Menezes, R and von Dolinger de Brito Röder, D}, title = {Quantification of biofilm produced by clinical, environment and hands' isolates Klebsiella species using colorimetric and classical methods.}, journal = {Journal of microbiological methods}, volume = {185}, number = {}, pages = {106231}, doi = {10.1016/j.mimet.2021.106231}, pmid = {33930475}, issn = {1872-8359}, mesh = {Biofilms/*growth & development ; Brazil ; Colorimetry/*methods ; Environment ; Humans ; Klebsiella/*isolation & purification ; Klebsiella Infections/diagnosis ; Klebsiella oxytoca/isolation & purification ; Klebsiella pneumoniae/isolation & purification ; }, abstract = {Some species of Klebsiella, such as Klebsiella pneumoniae and Klebsiella oxytoca, are important nosocomial pathogens frequently involved in outbreaks in Neonatal Intensive Care Units (NICU) and have the ability to form a biofilm. This study aims to evaluate the biofilm production of K. pneumoniae and K. oxytoca isolates collected from the hands of health professionals, neonates' blood and the environment of a Brazilian NICU, using three colorimetric methods and a classical method of counting the colony-forming units and compare the analysis among these techniques. The biofilm formation was carried out by the microplate technique, using three colorimetric assays: crystal violet, safranin and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl) -5 [(phenylamino) arbonyl] - 2H-tetrazolium hydroxide (XTT). Also, colony-forming units were determined. Twenty-eight isolates of K. pneumoniae were collected from the blood, hands and environment and five of K. oxytoca from the hands and environment. All of them were strong biofilm producers, but K. pneumoniae isolates produced more biofilm than K. oxytoca when compared to the American Type Culture Collection (ATCC) strains used as positive controls. The number of viable cells in the biofilm produced by K. pneumoniae isolated from blood was significantly higher than in the control sample. Regarding the three colorimetric tests used in the study, the violet crystal obtained a higher absorbance average. The use of crystal-violet and XTT in the evaluation of biofilm in vitro make possible a complete analysis, since that it can quantify the total biomass (including the extracellular matrix) and evaluate the metabolic activity. In conclusion, this study identified isolates of K. pneumoniae and K. oxytoca that produce biofilms in the NICU and the bloodstream of neonates. This fact deserves attention since these patients are immunocompromised. The best methods will be chosen to answer research questions by always adopting more than one method so that more than one parameter or component of the biofilm is analyzed.}, } @article {pmid33927980, year = {2021}, author = {Yang, Q and Wang, Y and An, Q and Sa, R and Zhang, D and Xu, R}, title = {Research on the role of LuxS/AI-2 quorum sensing in biofilm of Leuconostoc citreum 37 based on complete genome sequencing.}, journal = {3 Biotech}, volume = {11}, number = {4}, pages = {189}, pmid = {33927980}, issn = {2190-572X}, abstract = {UNLABELLED: Leuconostoc citreum, a type of food-grade probiotic bacteria, plays an important role in food fermentation and intestinal probiotics. Biofilms help bacteria survive under adverse conditions, and LuxS/AI-2-dependent quorum sensing (QS) plays an important role in the regulation of their biofilm-forming activities. L. citreum 37 was a biofilm-forming strain isolated from dairy products. The aim of this study was to analyze genes involved in the LuxS/AI-2 system based on genome sequencing and biofilm formation of L. citreum 37. Genome assembly yielded two contigs (one chromosome and one plasmid), and the complete genome contained 1,946,279 base pairs (bps) with a G + C content of 38.91%. The genome sequence analysis showed that there were several pathways such as the two-component system, QS, and seven other signal pathways, and 26 genes (including luxS, pfs, and 24 other genes) may participate in QS related to biofilm formation. All these results showed that the LuxS/AI-2 system is complete in the genome of L. citreum 37. The quantitative polymerase chain reaction (qPCR) of pfs, luxS genes, and AI-2 production of L. citreum 37 in planktonic state and biofilm state showed that the expression of pfs and luxS genes was consistent with the production of AI-2 and was positively correlated with biofilm formation. After luxS of L. citreum 37 expressed in Escherichia coli BL21, AI-2 production was detected, suggesting that the luxS gene played an important role in AI-2 synthesis, Therefore, luxS may regulate the biofilm formation of L. citreum 37 by participating in AI-2 synthesis. It is projected that results of this study could help facilitate further understanding and application of L. citreum 37.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02747-2.}, } @article {pmid33927701, year = {2021}, author = {An, AY and Choi, KG and Baghela, AS and Hancock, REW}, title = {An Overview of Biological and Computational Methods for Designing Mechanism-Informed Anti-biofilm Agents.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {640787}, pmid = {33927701}, issn = {1664-302X}, abstract = {Bacterial biofilms are complex and highly antibiotic-resistant aggregates of microbes that form on surfaces in the environment and body including medical devices. They are key contributors to the growing antibiotic resistance crisis and account for two-thirds of all infections. Thus, there is a critical need to develop anti-biofilm specific therapeutics. Here we discuss mechanisms of biofilm formation, current anti-biofilm agents, and strategies for developing, discovering, and testing new anti-biofilm agents. Biofilm formation involves many factors and is broadly regulated by the stringent response, quorum sensing, and c-di-GMP signaling, processes that have been targeted by anti-biofilm agents. Developing new anti-biofilm agents requires a comprehensive systems-level understanding of these mechanisms, as well as the discovery of new mechanisms. This can be accomplished through omics approaches such as transcriptomics, metabolomics, and proteomics, which can also be integrated to better understand biofilm biology. Guided by mechanistic understanding, in silico techniques such as virtual screening and machine learning can discover small molecules that can inhibit key biofilm regulators. To increase the likelihood that these candidate agents selected from in silico approaches are efficacious in humans, they must be tested in biologically relevant biofilm models. We discuss the benefits and drawbacks of in vitro and in vivo biofilm models and highlight organoids as a new biofilm model. This review offers a comprehensive guide of current and future biological and computational approaches of anti-biofilm therapeutic discovery for investigators to utilize to combat the antibiotic resistance crisis.}, } @article {pmid33927051, year = {2021}, author = {Kovács, ÁT and Stanley-Wall, NR}, title = {Biofilm Dispersal for Spore Release in Bacillus subtilis.}, journal = {Journal of bacteriology}, volume = {203}, number = {14}, pages = {e0019221}, pmid = {33927051}, issn = {1098-5530}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/genetics/growth & development/*physiology ; *Biofilms ; Calcium/metabolism ; Spores, Bacterial/genetics/growth & development/*physiology ; }, abstract = {The dispersal of bacterial cells from a matured biofilm can be mediated either by active or passive mechanisms. In this issue of the Journal of Bacteriology, Nishikawa and Kobayashi demonstrate that the presence of calcium influences the dispersal of spores from the pellicle biofilm of Bacillus subtilis (M. Nishikawa and K. Kobayashi, J Bacteriol 203:e00114-21, 2021, https://doi.org/10.1128/JB.00114-21). The authors propose that temporal heterogeneity in matrix production and chelation of calcium by dipicolinic acid in spores weakens the biofilm matrix and causes passive dispersal.}, } @article {pmid33927049, year = {2021}, author = {Nishikawa, M and Kobayashi, K}, title = {Calcium Prevents Biofilm Dispersion in Bacillus subtilis.}, journal = {Journal of bacteriology}, volume = {203}, number = {14}, pages = {e0011421}, pmid = {33927049}, issn = {1098-5530}, mesh = {Bacillus subtilis/genetics/growth & development/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Calcium/*metabolism ; Gene Expression Regulation, Bacterial ; Operon ; Picolinic Acids/metabolism ; Spores, Bacterial/genetics/growth & development/metabolism ; }, abstract = {Biofilm dispersion is the final stage of biofilm development, during which biofilm cells actively escape from biofilms in response to deteriorating conditions within the biofilm. Biofilm dispersion allows cells to spread to new locations and form new biofilms in better locations. However, dispersal mechanisms have been elucidated only in a limited number of bacteria. Here, we investigated biofilm dispersion in Bacillus subtilis. Biofilm dispersion was clearly observed when B. subtilis was grown under static conditions in modified LB medium containing glycerol and manganese. Biofilm dispersion was synergistically caused by two mechanisms: decreased expression of the epsA operon encoding exopolysaccharide synthetases and the induction of sporulation. Indeed, constitutive expression of the epsA operon in the sporulation-defective ΔsigK mutant prevented biofilm dispersion. The addition of calcium to the medium prevented biofilm dispersion without significantly affecting the expression of the epsA operon and sporulation genes. In synthetic medium, eliminating calcium did not prevent the expression of biofilm matrix genes and, thereby, biofilm formation, but it attenuated biofilm architecture. These results indicate that calcium structurally stabilizes biofilms and causes resistance to biofilm dispersion mechanisms. Sporulation-dependent biofilm dispersion required the spoVF operon, encoding dipicolinic acid (DPA) synthase. During sporulation, an enormous amount of DPA is synthesized and stored in spores as a chelate with calcium. We speculate that, during sporulation, calcium bound to biofilm matrix components may be transported to spores as a calcium-DPA complex, which weakens biofilm structure and leads to biofilm dispersion. IMPORTANCE Bacteria growing as biofilms are notoriously difficult to eradicate and sometimes pose serious threats to public health. Bacteria escape from biofilms by degrading them when biofilm conditions deteriorate. This process, called biofilm dispersion, has been studied as a promising strategy for safely controlling biofilms. However, the regulation and mechanism of biofilm dispersion has been elucidated only in a limited number of bacteria. Here, we identified two biofilm dispersion mechanisms in the Gram-positive, spore-forming bacterium Bacillus subtilis. The addition of calcium to the medium stabilized biofilms and caused resistance to dispersal mechanisms. Our findings provide new insights into biofilm dispersion and biofilm control.}, } @article {pmid33925936, year = {2021}, author = {Schafer, ME and McNeely, T}, title = {Combining Visible Light and Non-Focused Ultrasound Significantly Reduces Propionibacterium acnes Biofilm While Having Limited Effect on Host Cells.}, journal = {Microorganisms}, volume = {9}, number = {5}, pages = {}, pmid = {33925936}, issn = {2076-2607}, support = {R43 AR067650/AR/NIAMS NIH HHS/United States ; R43AR067650/AR/NIAMS NIH HHS/United States ; }, abstract = {Bacterial biofilms are highly resistant to antibiotics and have been implicated in the etiology of 60%-80% of chronic microbial infections. We tested a novel combination of low intensity ultrasound and blue light against biofilm and planktonic bacteria. A laboratory prototype was built which produced both energies uniformly and coincidently from a single treatment head, impinging upon a 4.45 cm[2] target. To demonstrate proof of concept, Propionibacterium acnes biofilms were cultured on Millicell hanging inserts in 6-well plates. Hanging inserts with biofilms were treated in a custom exposure chamber designed to minimize unwanted ultrasound reflections. Coincident delivery of both energies demonstrated synergy over either alone, killing both stationary planktonic and biofilm cultures of P. acnes. Reduction in biofilm bacteria was dose dependent on exposure time (i.e., energy delivered). P. acnes biofilms were significantly reduced by dual energy treatment (p < 0.0001), with a >1 log10 reduction after a 5 min (9 J/cm[2]) and >3 log10 reduction after a 30 min (54 J/cm[2]) treatment (p < 0.05). Mammalian cells were found to be unaffected by the treatment. Both the light and the ultrasound energies are at levels previously cleared by the FDA. Therefore, this combination treatment could be used as a safe, efficacious method to treat biofilm related syndromes.}, } @article {pmid33924416, year = {2021}, author = {Dydak, K and Junka, A and Dydak, A and Brożyna, M and Paleczny, J and Fijalkowski, K and Kubielas, G and Aniołek, O and Bartoszewicz, M}, title = {In Vitro Efficacy of Bacterial Cellulose Dressings Chemisorbed with Antiseptics against Biofilm Formed by Pathogens Isolated from Chronic Wounds.}, journal = {International journal of molecular sciences}, volume = {22}, number = {8}, pages = {}, pmid = {33924416}, issn = {1422-0067}, support = {STM.D230.20.053//Wroclaw Medical University/ ; }, mesh = {Anti-Infective Agents/pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Bacteria/drug effects/growth & development/*isolation & purification ; Bandages/*microbiology ; Biofilms/drug effects/*growth & development ; Cellulose/*pharmacology ; Chronic Disease ; Drug Resistance, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; Silver/pharmacology ; Wounds and Injuries/*microbiology ; Yeasts/drug effects ; }, abstract = {Local administration of antiseptics is required to prevent and fight against biofilm-based infections of chronic wounds. One of the methods used for delivering antiseptics to infected wounds is the application of dressings chemisorbed with antimicrobials. Dressings made of bacterial cellulose (BC) display several features, making them suitable for such a purpose. This work aimed to compare the activity of commonly used antiseptic molecules: octenidine, polyhexanide, povidone-iodine, chlorhexidine, ethacridine lactate, and hypochlorous solutions and to evaluate their usefulness as active substances of BC dressings against 48 bacterial strains (8 species) and 6 yeast strains (1 species). A silver dressing was applied as a control material of proven antimicrobial activity. The methodology applied included the assessment of minimal inhibitory concentrations (MIC) and minimal biofilm eradication concentration (MBEC), the modified disc-diffusion method, and the modified antibiofilm dressing activity measurement (A.D.A.M.) method. While in 96-well plate-based methods (MIC and MBEC assessment), the highest antimicrobial activity was recorded for chlorhexidine, in the modified disc-diffusion method and in the modified A.D.A.M test, povidone-iodine performed the best. In an in vitro setting simulating chronic wound conditions, BC dressings chemisorbed with polyhexanide, octenidine, or povidone-iodine displayed a similar or even higher antibiofilm activity than the control dressing containing silver molecules. If translated into clinical conditions, the obtained results suggest high applicability of BC dressings chemisorbed with antiseptics to eradicate biofilm from chronic wounds.}, } @article {pmid33924336, year = {2021}, author = {Genovese, C and D'Angeli, F and Bellia, F and Distefano, A and Spampinato, M and Attanasio, F and Nicolosi, D and Di Salvatore, V and Tempera, G and Lo Furno, D and Mannino, G and Milardo, F and Li Volti, G}, title = {In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33924336}, issn = {2079-6382}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) represents a serious threat to public health, due to its large variety of pathogenetic mechanisms. Accordingly, the present study aimed to investigate the anti-MRSA activities of Krameria lappacea, a medicinal plant native to South America. Through Ultra-High-Performance Liquid Chromatography coupled with High-Resolution Mass spectrometry, we analyzed the chemical composition of Krameria lappacea root extract (KLRE). The antibacterial activity of KLRE was determined by the broth microdilution method, also including the minimum biofilm inhibitory concentration and minimum biofilm eradication concentration. Besides, we evaluated the effect on adhesion and invasion of human lung carcinoma A549 cell line by MRSA strains. The obtained results revealed an interesting antimicrobial action of this extract, which efficiently inhibit the growth, biofilm formation, adhesion and invasion of MRSA strains. Furthermore, the chemical analysis revealed the presence in the extract of several flavonoid compounds and type-A and type-B proanthocyanidins, which are known for their anti-adhesive effects. Taken together, our findings showed an interesting antimicrobial activity of KLRE, giving an important contribution to the current knowledge on the biological activities of this plant.}, } @article {pmid33922823, year = {2021}, author = {Dudek-Wicher, R and Paleczny, J and Kowalska-Krochmal, B and Szymczyk-Ziółkowska, P and Pachura, N and Szumny, A and Brożyna, M}, title = {Activity of Liquid and Volatile Fractions of Essential Oils against Biofilm Formed by Selected Reference Strains on Polystyrene and Hydroxyapatite Surfaces.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {33922823}, issn = {2076-0817}, support = {STM.D230.17.004//Wroclaw Medical University/ ; STM.D230.20.127//Wroclaw Medical University/ ; }, abstract = {Biofilms are surface-attached, structured microbial communities displaying higher tolerance to antimicrobial agents in comparison to planktonic cells. An estimated 80% of all infections are thought to be biofilm-related. The drying pipeline of new antibiotics efficient against biofilm-forming pathogens urges the search for alternative routes of treatment. Essential Oils (EOs), extracted from medicinally important plants, are a reservoir of bioactive compounds that may serve as a foothold in investigating novel antibiofilm compounds. The aim of this study was to compare antimicrobial activity of liquid and volatile fractions of tested EOs against biofilm-forming pathogens using different techniques. In this research, we tested five EOs, extracted from Syzygium aromaticum L., Boswelia serrata Roxb., Juniperus virginiana L., Pelargonium graveolens L. and Melaleuca alternifolia Cheel., against planktonic and biofilm forms of five selected reference strains, namely Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. To obtain cohesive results, we applied four various methodological approaches: to assess the activity of the liquid fraction of EOs, disc diffusion and the microdilution method were applied; to test EOs' volatile fraction, the AntiBioVol assay and modified Antibiofilm Dressing Activity Measurement (A.D.A.M.) were used. The molecular composition and dynamics of antimicrobial substances released from specific EOs was measured using Gas Chromatography-Mass Spectrometry (GC-MS). The antimicrobial potency of EO's volatile fraction against biofilm formed by tested strains differed from that of the liquid fraction and was related to the molecular weight of volatile compounds. The liquid fraction of CW-EO and volatile fraction of F-EO acted in the strongest manner against biofilm of C. albicans. The addition of 0.5% Tween 20 to liquid phase, enhanced activity of G-EO against E. coli and K. pneumoniae biofilm. EO activity depended on the microbial species it was applied against and the chosen assessment methodology. While all tested EOs have shown a certain level of antimicrobial and antibiofilm effect, our results indicate that the choice of EO to be applied against a specific biofilm-forming pathogen requires careful consideration with regard to the above-listed aspects. Nevertheless, the results presented in this research contribute to the growing body of evidence indicating the beneficial effects of EOs, which may be applied to fight biofilm-forming pathogens.}, } @article {pmid33922089, year = {2021}, author = {Benavent, C and Torrado-Salmerón, C and Torrado-Santiago, S}, title = {Development of a Solid Dispersion of Nystatin with Maltodextrin as a Carrier Agent: Improvements in Antifungal Efficacy against Candida spp. Biofilm Infections.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {5}, pages = {}, pmid = {33922089}, issn = {1424-8247}, support = {[MICINU, ref. RTI2018-093940-B-100//Ministerio de ciencia e innovación/ ; [Research Group 910939]//Faculty of Pharmacy, University Complutense of Madrid/ ; }, abstract = {The aim of this study was to improve the treatment of Candida albicans biofilms through the use of nystatin solid dispersions developed using maltodextrins as a hyperosmotic carrier. Characterization studies by differential scanning calorimetry, X-ray diffraction, dissolution studies, and particle size analysis were performed to evaluate changes in nystatin crystallinity. Antifungal activity and anti-biofilm efficacy were assessed by microbiological techniques. The results for nystatin solid dispersions showed that the enhancement of antifungal activity may be related to the high proportions of maltodextrins. Anti-biofilm assays showed a significant reduction (more than 80%) on biofilm formation with SD-N:MD [1:6] compared to the nystatin reference suspension. The elaboration process and physicochemical properties of SD-N:MD [1:6] could be a promising strategy for treatment of Candida biofilms.}, } @article {pmid33921904, year = {2021}, author = {Chan, Y and Wu, XH and Chieng, BW and Ibrahim, NA and Then, YY}, title = {Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {4}, pages = {}, pmid = {33921904}, issn = {2079-4991}, support = {FRGS/1/2018/STG07/IMU/03/1//Ministry of Higher Education, Malaysia/ ; }, abstract = {Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.}, } @article {pmid33921809, year = {2021}, author = {Moreno-Martínez, AE and Gómez-Molero, E and Sánchez-Virosta, P and Dekker, HL and de Boer, A and Eraso, E and Bader, O and de Groot, PWJ}, title = {High Biofilm Formation of Non-Smooth Candida parapsilosis Correlates with Increased Incorporation of GPI-Modified Wall Adhesins.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33921809}, issn = {2076-0817}, support = {SAF2013-47570-P, SAF2017-86188-P//Spanish Ministry of Economy and Competitiveness/ ; SBPLY/19/180501/000114//Regional Government of Castilla-La Mancha (JCCM)/ ; SAF2013-47570-P, SAF2017-86188-P, SBPLY/19/180501/000114//FEDER/ ; GIC15/78 IT-990-16//Consejería de Educación, Universidades e Investigación of Gobierno Vasco-Eusko Jaurlaritza/ ; MC-ITN-606786//FP7 People: Marie-Curie Actions/ ; }, abstract = {Candida parapsilosis is among the most frequent causes of candidiasis. Clinical isolates of this species show large variations in colony morphotype, ranging from round and smooth to a variety of non-smooth irregular colony shapes. A non-smooth appearance is related to increased formation of pseudohyphae, higher capacity to form biofilms on abiotic surfaces, and invading agar. Here, we present a comprehensive study of the cell wall proteome of C. parapsilosis reference strain CDC317 and seven clinical isolates under planktonic and sessile conditions. This analysis resulted in the identification of 40 wall proteins, most of them homologs of known Candida albicans cell wall proteins, such as Gas, Crh, Bgl2, Cht2, Ecm33, Sap, Sod, Plb, Pir, Pga30, Pga59, and adhesin family members. Comparative analysis of exponentially growing and stationary phase planktonic cultures of CDC317 at 30 °C and 37 °C revealed only minor variations. However, comparison of smooth isolates to non-smooth isolates with high biofilm formation capacity showed an increase in abundance and diversity of putative wall adhesins from Als, Iff/Hyr, and Hwp families in the latter. This difference depended more strongly on strain phenotype than on the growth conditions, as it was observed in planktonic as well as biofilm cells. Thus, in the set of isolates analyzed, the high biofilm formation capacity of non-smooth C. parapsilosis isolates with elongated cellular phenotypes correlates with the increased surface expression of putative wall adhesins in accordance with their proposed cellular function.}, } @article {pmid33921583, year = {2021}, author = {Khambhati, K and Patel, J and Saxena, V and A, P and Jain, N}, title = {Gene Regulation of Biofilm-Associated Functional Amyloids.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33921583}, issn = {2076-0817}, support = {ECR/2018/002490//Science and Engineering Research Board/ ; I/SEED/NJ/20190019//Indian Institute of technology Jodhpur/ ; }, abstract = {Biofilms are bacterial communities encased in a rigid yet dynamic extracellular matrix. The sociobiology of bacterial communities within a biofilm is astonishing, with environmental factors playing a crucial role in determining the switch from planktonic to a sessile form of life. The mechanism of biofilm biogenesis is an intriguingly complex phenomenon governed by the tight regulation of expression of various biofilm-matrix components. One of the major constituents of the biofilm matrix is proteinaceous polymers called amyloids. Since the discovery, the significance of biofilm-associated amyloids in adhesion, aggregation, protection, and infection development has been much appreciated. The amyloid expression and assembly is regulated spatio-temporarily within the bacterial cells to perform a diverse function. This review provides a comprehensive account of the genetic regulation associated with the expression of amyloids in bacteria. The stringent control ensures optimal utilization of amyloid scaffold during biofilm biogenesis. We conclude the review by summarizing environmental factors influencing the expression and regulation of amyloids.}, } @article {pmid33921531, year = {2021}, author = {Kligman, S and Ren, Z and Chung, CH and Perillo, MA and Chang, YC and Koo, H and Zheng, Z and Li, C}, title = {The Impact of Dental Implant Surface Modifications on Osseointegration and Biofilm Formation.}, journal = {Journal of clinical medicine}, volume = {10}, number = {8}, pages = {}, pmid = {33921531}, issn = {2077-0383}, abstract = {Implant surface design has evolved to meet oral rehabilitation challenges in both healthy and compromised bone. For example, to conquer the most common dental implant-related complications, peri-implantitis, and subsequent implant loss, implant surfaces have been modified to introduce desired properties to a dental implant and thus increase the implant success rate and expand their indications. Until now, a diversity of implant surface modifications, including different physical, chemical, and biological techniques, have been applied to a broad range of materials, such as titanium, zirconia, and polyether ether ketone, to achieve these goals. Ideal modifications enhance the interaction between the implant's surface and its surrounding bone which will facilitate osseointegration while minimizing the bacterial colonization to reduce the risk of biofilm formation. This review article aims to comprehensively discuss currently available implant surface modifications commonly used in implantology in terms of their impact on osseointegration and biofilm formation, which is critical for clinicians to choose the most suitable materials to improve the success and survival of implantation.}, } @article {pmid33920743, year = {2021}, author = {Minkiewicz-Zochniak, A and Jarzynka, S and Iwańska, A and Strom, K and Iwańczyk, B and Bartel, M and Mazur, M and Pietruczuk-Padzik, A and Konieczna, M and Augustynowicz-Kopeć, E and Olędzka, G}, title = {Biofilm Formation on Dental Implant Biomaterials by Staphylococcus aureus Strains Isolated from Patients with Cystic Fibrosis.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {8}, pages = {}, pmid = {33920743}, issn = {1996-1944}, abstract = {Implants made of ceramic and metallic elements, which are used in dentistry, may either promote or hinder the colonization and adhesion of bacteria to the surface of the biomaterial to varying degrees. The increased interest in the use of dental implants, especially in patients with chronic systemic diseases such as cystic fibrosis (CF), is caused by an increase in disease complications. In this study, we evaluated the differences in the in vitro biofilm formation on the surface of biomaterials commonly used in dentistry (Ti-6Al-4V, cobalt-chromium alloy (CoCr), and zirconia) by Staphylococcus aureus isolated from patients with CF. We demonstrated that S. aureus adherence and growth depends on the type of material used and its surface topography. Weaker bacterial biofilm formation was observed on zirconia surfaces compared to titanium and cobalt-chromium alloy surfaces. Moreover, scanning electron microscopy showed clear differences in bacterial aggregation, depending on the type of biomaterial used. Over the past several decades, S. aureus strains have developed several mechanisms of resistance, especially in patients on chronic antibiotic treatment such as CF. Therefore, the selection of an appropriate implant biomaterial with limited microorganism adhesion characteristics can affect the occurrence and progression of oral cavity infections, particularly in patients with chronic systemic diseases.}, } @article {pmid33919962, year = {2021}, author = {Wieland, T and Assmann, J and Bethe, A and Fidelak, C and Gmoser, H and Janßen, T and Kotthaus, K and Lübke-Becker, A and Wieler, LH and Urban, GA}, title = {A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation.}, journal = {Sensors (Basel, Switzerland)}, volume = {21}, number = {8}, pages = {}, pmid = {33919962}, issn = {1424-8220}, mesh = {Animals ; *Anti-Bacterial Agents ; *Bacterial Adhesion ; Biofilms ; Cattle ; Escherichia coli ; Female ; Humans ; Microbial Sensitivity Tests ; Pore Forming Cytotoxic Proteins ; }, abstract = {The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.}, } @article {pmid33919891, year = {2021}, author = {Okaro, U and George, S and Anderson, B}, title = {What Is in a Cat Scratch? Growth of Bartonella henselae in a Biofilm.}, journal = {Microorganisms}, volume = {9}, number = {4}, pages = {}, pmid = {33919891}, issn = {2076-2607}, abstract = {Bartonella henselae (B. henselae) is a gram-negative bacterium that causes cat scratch disease, bacteremia, and endocarditis, as well as other clinical presentations. B. henselae has been shown to form a biofilm in vitro that likely plays a role in the establishment and persistence of the bacterium in the host. Biofilms are also known to form in the cat flea vector; hence, the ability of this bacterium to form a biofilm has broad biological significance. The release of B. henselae from a biofilm niche appears to be important in disease persistence and relapse in the vertebrate host but also in transmission by the cat flea vector. It has been shown that the BadA adhesin of B. henselae is critical for adherence and biofilm formation. Thus, the upregulation of badA is important in initiating biofilm formation, and down-regulation is important in the release of the bacterium from the biofilm. We summarize the current knowledge of biofilm formation in Bartonella species and the role of BadA in biofilm formation. We discuss the evidence that defines possible mechanisms for the regulation of the genes required for biofilm formation. We further describe the regulation of those genes in the conditions that mimic both the arthropod vector and the mammalian host for B. henselae. The treatment for persistent B. henselae infection remains a challenge; hence, a better understanding of the mechanisms by which this bacterium persists in its host is critical to inform future efforts to develop drugs to treat such infections.}, } @article {pmid33918930, year = {2021}, author = {Conwell, M and Dooley, JSG and Naughton, PJ}, title = {A Novel Biofilm Model System to Visualise Conjugal Transfer of Vancomycin Resistance by Environmental Enterococci.}, journal = {Microorganisms}, volume = {9}, number = {4}, pages = {}, pmid = {33918930}, issn = {2076-2607}, support = {001//Department of Employment and Learning Northern Ireland/ ; }, abstract = {Enterococci and biofilm-associated infections are a growing problem worldwide, given the rise in antibiotic resistance in environmental and clinical settings. The increasing incidence of antibiotic resistance and its propagation potential within enterococcal biofilm is a concern. This requires a deeper understanding of how enterococcal biofilm develops, and how antibiotic resistance transfer takes place in these biofilms. Enterococcal biofilm assays, incorporating the study of antibiotic resistance transfer, require a system which can accommodate non-destructive, real-time experimentation. We adapted a Gene Frame[®] combined with fluorescence microscopy as a novel non-destructive platform to study the conjugal transfer of vancomycin resistance in an established enterococcal biofilm.A multi-purpose fluorescent in situ hybridisation (FISH) probe, in a novel application, allowed the identification of low copy number mobile elements in the biofilm. Furthermore, a Hoechst stain and ENU 1470 FISH probe identified Enterococcus faecium transconjugants by excluding Enterococcus faecalis MF06036 donors. Biofilm created with a rifampicin resistant E. faecalis (MW01105[Rif]) recipient had a transfer efficiency of 2.01 × 10[-3]; double that of the biofilm primarily created by the donor (E. faecalis MF06036). Conjugation in the mixed enterococcal biofilm was triple the efficiency of donor biofilm. Double antibiotic treatment plus lysozyme combined with live/dead imaging provided fluorescent micrographs identifying de novo enterococcal vancomycin resistant transconjugants inside the biofilm. This is a model system for the further study of antibiotic resistance transfer events in enterococci. Biofilms promote the survival of enterococci and reduce the effectiveness of drug treatment in clinical settings, hence giving enterococci an advantage. Enterococci growing in biofilms exchange traits by means of horizontal gene transfer, but currently available models make study difficult. This work goes some way to providing a non-destructive, molecular imaging-based model system for the detection of antibiotic resistance gene transfer in enterococci.}, } @article {pmid33918842, year = {2021}, author = {Álvarez-Sagües, A and Herce, N and Amador, U and Llinares-Pinel, F and Nistal-Villan, E and Presa, J and Álvarez, L and Azabal, M}, title = {Efficacy of EDTA and HEDP Chelators in the Removal of Mature Biofilm of Enterococcus faecalis by PUI and XPF File Activation.}, journal = {Dentistry journal}, volume = {9}, number = {4}, pages = {}, pmid = {33918842}, issn = {2304-6767}, abstract = {BACKGROUND: Biofilm removal from the root canal during endodontic treatment is necessary to prevent further complications. Irrigation is essential to success. Several irrigants have been proposed without a proper comparison. The aim of the study is to compare the antibacterial capacity of different activated irrigants using passive ultrasonic activation (PUI) or XP-Endo finisher (XPF).

METHODS: A total of 100 instrumented teeth were incubated in an Eppendorf tube containing 0.5 McFarland of Enterococcus faecalis and incubated for 2 weeks at 37 °C. Roots were divided into 5 groups (n = 20) according to the irrigant type: ethylenediaminetetraacetic acid (EDTA) (17%), ethydronic acid (HEDP) (9%) mixed with 5.25% sodium hypochlorite (NaOCl), EDTA (17%) mixed with 5.25% NaOCl, PBS, and a control group. Each group was divided into two subgroups (n = 10): PUI and XPF.

RESULTS: As compared to the untreated control group, the irrigators included in the study had a significant effect in bacteria reduction. The obtained results show HEDP to be the most effective irrigant, since no bacteria were recovered after treatment of this group, followed by EDTA mixed with NaOCl and, finally, the EDTA-irrigated group.

CONCLUSIONS: HEDP is the best irrigating agent in combination with XPF or PUI file activation to eliminate bacteria in our experimental model.}, } @article {pmid33918682, year = {2021}, author = {Lin, CN and Ding, SJ and Chen, CC}, title = {Synergistic Photoantimicrobial Chemotherapy of Methylene Blue-Encapsulated Chitosan on Biofilm-Contaminated Titanium.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {4}, pages = {}, pmid = {33918682}, issn = {1424-8247}, abstract = {Intensive efforts have been made to eliminate or substantial reduce bacterial adhesion and biofilm formation on titanium implants. However, in the management of peri-implantitis, the methylene blue (MB) photosensitizer commonly used in photoantimicrobial chemotherapy (PACT) is limited to a low retention on the implant surface. The purpose of this study was to assess enhancive effect of water-soluble quaternary ammonium chitosan (QTS) on MB retention on biofilm-infected SLA (sandblasted, large grid, and acid-etched) Ti alloy surfaces in vitro. The effectiveness of QTS + MB with different concentrations in eliminating Gram-negative A. actinomycetemcomitans or Gram-positive S. mutans bacteria was compared before and after PACT. Bacterial counting and lipopolysaccharide (LPS) detection were examined, and then the growth of human osteoblast-like MG63 cells was evaluated. The results indicated that the synergistic QTS + MB with retention ability significantly decreased the biofilm accumulation on the Ti alloy surface, which was better than the same concentration of 1 wt% methyl cellulose (MC). More importantly, the osteogenic activity of MG63 cells on the disinfected sample treated by QTS + MB-PACT modality was comparable to that of sterile Ti control, significantly higher than that by MC + MB-PACT modality. It is concluded that, in terms of improved retention efficacy, effective bacteria eradication, and enhanced cell growth, synergistically, PACT using the 100 μg/mL MB-encapsulated 1% QTS was a promising modality for the treatment of peri-implantitis.}, } @article {pmid33918561, year = {2021}, author = {Melo, LDR and Azevedo, NF}, title = {New Insights on Biofilm Antimicrobial Strategies.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33918561}, issn = {2079-6382}, abstract = {Over the last few decades, the study of microbial biofilms has been gaining interest among the scientific community [...].}, } @article {pmid33918384, year = {2021}, author = {Zinicovscaia, I and Yushin, N and Grozdov, D and Abdusamadzoda, D and Safonov, A and Rodlovskaya, E}, title = {Zinc-Containing Effluent Treatment Using Shewanella xiamenensis Biofilm Formed on Zeolite.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {7}, pages = {}, pmid = {33918384}, issn = {1996-1944}, support = {18-29-25023MK//Russian Foundation for Basic Research/ ; }, abstract = {The sorption properties of Shewanella xiamenensis biofilm formed on zeolite (mineral-organic sorbent) as a sorbent have been investigated aiming to determine its suitability for complex zinc-containing effluent treatment. The optimum conditions for metal sorption from synthetic solutions were evaluated by changing the pH, zinc concentration, temperature, and time of sorption. The highest removal of metal ions was attained at pH range 3.0-6.0 within 60-150 min of sorbent-sorbate contact. The results obtained from the equilibrium studies were described using the Langmuir, Freundlich, and Temkin models. Maximum sorption capacity of the sorbent calculated from the Langmuir model changed from 3.4 to 6.5 mg/g. High coefficient of determination values calculated for pseudo-second-order and Elovich models indicate the predominant role of chemisorption in metal removal. Gibbs energy and ∆H° values point at the spontaneous and endothermic character of the sorption. The effect of pH and biosorbent mass on Zn(II) sorption from industrial effluent with an initial Zn(II) concentration of 52.8 mg/L was tested. Maximum removal of zinc ions (85%) was achieved at pH 6.0 by applying a two-step treatment system.}, } @article {pmid33918377, year = {2021}, author = {Rakov, C and Ben Porat, S and Alkalay-Oren, S and Yerushalmy, O and Abdalrhman, M and Gronovich, N and Huang, L and Pride, D and Coppenhagen-Glazer, S and Nir-Paz, R and Hazan, R}, title = {Targeting Biofilm of MDR Providencia stuartii by Phages Using a Catheter Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33918377}, issn = {2079-6382}, support = {‎2017123‎//United States-Israel Binational Science Foundation/ ; ISF1349/20‎//Israel Science Foundation/ ; A2232‎//Rosetrees Trust/ ; NA//Milgrom Family Support Program‎/ ; }, abstract = {Providencia spp. are emerging pathogens mainly in nosocomial infections. Providencia stuartii in particular is involved in urinary tract infections and contributes significantly to the high incidence of biofilm-formation in catheterized patients. Furthermore, recent reports suggested a role for multiple drug resistant (MDR) P. stuartii in hospital-associated outbreaks which leads to excessive complications resulting in challenging treatments. Phage therapy is currently one of the most promising solutions to combat antibiotic-resistant infections. However, the number of available phages targeting Providencia spp. is extremely limited, restricting the use of phage therapy in such cases. In the present study, we describe the isolation and characterization of 17 lytic and temperate bacteriophages targeting clinical isolates of Providencia spp. as part of the Israeli Phage Bank (IPB). These phages, isolated from sewage samples, were evaluated for host range activity and effectively eradicated 95% of the tested bacterial strains isolated from different geographic locations and displaying a wide range of antibiotic resistance. Their lytic activity is demonstrated on agar plates, planktonic cultures, and biofilm formed in a catheter model. The results suggest that these bacteriophages can potentially be used for treatment of antibiotic-resistant Providencia spp. infections in general and of urinary tract infections in particular.}, } @article {pmid33918040, year = {2021}, author = {Wickremasinghe, H and Yu, HH and Azad, MAK and Zhao, J and Bergen, PJ and Velkov, T and Zhou, QT and Zhu, Y and Li, J}, title = {Clinically Relevant Concentrations of Polymyxin B and Meropenem Synergistically Kill Multidrug-Resistant Pseudomonas aeruginosa and Minimize Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33918040}, issn = {2079-6382}, support = {R01 AI132681/AI/NIAID NIH HHS/United States ; R01 AI146160/AI/NIAID NIH HHS/United States ; RO1 AI132681 and RO1 AI146160//National Institute of Allergy and Infectious Diseases/ ; }, abstract = {The emergence of antibiotic resistance has severely impaired the treatment of chronic respiratory infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa. Since the reintroduction of polymyxins as a last-line therapy against MDR Gram-negative bacteria, resistance to its monotherapy and recurrent infections continue to be reported and synergistic antibiotic combinations have been investigated. In this study, comprehensive in vitro microbiological evaluations including synergy panel screening, population analysis profiling, time-kill kinetics, anti-biofilm formation and membrane damage analysis studies were conducted to evaluate the combination of polymyxin B and meropenem against biofilm-producing, polymyxin-resistant MDR P. aeruginosa. Two phylogenetically unrelated MDR P. aeruginosa strains, FADDI-PA060 (MIC of polymyxin B [MICpolymyxin B], 64 mg/L; MICmeropenem, 64 mg/L) and FADDI-PA107 (MICpolymyxin B, 32 mg/L; MICmeropenem, 4 mg/L) were investigated. Genome sequencing identified 57 (FADDI-PA060) and 50 (FADDI-PA107) genes predicted to confer resistance to a variety of antimicrobials, as well as multiple virulence factors in each strain. The presence of resistance genes to a particular antibiotic class generally aligned with MIC results. For both strains, all monotherapies of polymyxin B failed with substantial regrowth and biofilm formation. The combination of polymyxin B (16 mg/L)/meropenem (16 mg/L) was most effective, enhancing initial bacterial killing of FADDI-PA060 by ~3 log10 CFU/mL, followed by a prolonged inhibition of regrowth for up to 24 h with a significant reduction in biofilm formation (* p < 0.05). Membrane integrity studies revealed a substantial increase in membrane depolarization and membrane permeability in the surviving cells. Against FADDI-PA107, planktonic and biofilm bacteria were completely eradicated. In summary, the combination of polymyxin B and meropenem demonstrated synergistic bacterial killing while reinstating the efficacy of two previously ineffective antibiotics against difficult-to-treat polymyxin-resistant MDR P. aeruginosa.}, } @article {pmid33917564, year = {2021}, author = {Hu, WS and Woo, DU and Kang, YJ and Koo, OK}, title = {Biofilm and Spore Formation of Clostridium perfringens and Its Resistance to Disinfectant and Oxidative Stress.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33917564}, issn = {2079-6382}, support = {2016R1D1A3B03931403//National Research Foundation of Korea/ ; 2019R1C1C100242712//National Research Foundation of Korea/ ; }, abstract = {Clostridium perfringens is a major human pathogen that causes gastroenteritis via enterotoxin production and has the ability to form spores and biofilms for environmental persistence and disease transmission. This study aimed to compare the disinfectant and environmental resistance properties of C. perfringens vegetative cells and spores in planktonic and sessile conditions, and to examine the nucleotide polymorphisms and transcription under sessile conditions in C. perfringens strains isolated from meat. The sporulation rate of sessile C. perfringens TYJAM-D-66 (cpe+) was approximately 19% at day 5, while those of CMM-C-80 (cpe-) and SDE-B-202 (cpe+) were only 0.26% and 0.67%, respectively, at day 7. When exposed to aerobic conditions for 36 h, TYJAM-D-66, CMM-C-80, and SDE-B-202 vegetative cells showed 1.70 log, 5.36 log, and 5.67 log reductions, respectively. After treatment with sodium hypochlorite, the survival rates of TYJAM-D-66 vegetative cells (53.6%) and spores (82.3%) in biofilms were higher than those of planktonic cells (9.23%). Biofilm- and spore-related genes showed different expression within TYJAM-D-66 (-4.66~113.5), CMM-C-80 (-3.02~2.49), and SDE-B-202 (-5.07~2.73). Our results indicate the resistance of sessile cells and spores of C. perfringens upon exposure to stress conditions after biofilm formation.}, } @article {pmid33917084, year = {2021}, author = {Barros, AC and Pereira, A and Melo, LF and Sousa, JPS}, title = {New Functionalized Macroparticles for Environmentally Sustainable Biofilm Control in Water Systems.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {33917084}, issn = {2079-6382}, support = {UIDB/00511/2020//Fundação para a Ciência e a Tecnologia/ ; Inn-INDIGO/0001/2014//Fundação para a Ciência e a Tecnologia/ ; POCI-01-0247-FEDER-033298//European Regional Development Fund/ ; SFRH/BD/146028/2019//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {Reverse osmosis (RO) depends on biocidal agents to control the operating costs associated to biofouling, although this implies the discharge of undesired chemicals into the aquatic environment. Therefore, a system providing pre-treated water free of biocides arises as an interesting solution to minimize the discharge of chemicals while enhancing RO filtration performance by inactivating bacteria that could form biofilms on the membrane system. This work proposes a pretreatment approach based on the immobilization of an industrially used antimicrobial agent (benzalkonium chloride-BAC) into millimetric aluminum oxide particles with prior surface activation with DA-dopamine. The antimicrobial efficacy of the functionalized particles was assessed against Escherichia coli planktonic cells through culturability and cell membrane integrity analysis. The results showed total inactivation of bacterial cells within five min for the highest particle concentration and 100% of cell membrane damage after 15 min for all concentrations. When reusing the same particles, a higher contact time was needed to reach the total inactivation, possibly due to partial blocking of immobilized biocide by dead bacteria adhering to the particles and to the residual leaching of biocide. The overall results support the use of Al2O3-DA-BAC particles as antimicrobial agents for sustainable biocidal applications in continuous water treatment systems.}, } @article {pmid33916474, year = {2021}, author = {Altay, O and Zhang, C and Turkez, H and Nielsen, J and Uhlén, M and Mardinoglu, A}, title = {Revealing the Metabolic Alterations during Biofilm Development of Burkholderia cenocepacia Based on Genome-Scale Metabolic Modeling.}, journal = {Metabolites}, volume = {11}, number = {4}, pages = {}, pmid = {33916474}, issn = {2218-1989}, abstract = {Burkholderia cenocepacia is among the important pathogens isolated from cystic fibrosis (CF) patients. It has attracted considerable attention because of its capacity to evade host immune defenses during chronic infection. Advances in systems biology methodologies have led to the emergence of methods that integrate experimental transcriptomics data and genome-scale metabolic models (GEMs). Here, we integrated transcriptomics data of bacterial cells grown on exponential and biofilm conditions into a manually curated GEM of B. cenocepacia. We observed substantial differences in pathway response to different growth conditions and alternative pathway susceptibility to extracellular nutrient availability. For instance, we found that blockage of the reactions was vital through the lipid biosynthesis pathways in the exponential phase and the absence of microenvironmental lysine and tryptophan are essential for survival. During biofilm development, bacteria mostly had conserved lipid metabolism but altered pathway activities associated with several amino acids and pentose phosphate pathways. Furthermore, conversion of serine to pyruvate and 2,5-dioxopentanoate synthesis are also identified as potential targets for metabolic remodeling during biofilm development. Altogether, our integrative systems biology analysis revealed the interactions between the bacteria and its microenvironment and enabled the discovery of antimicrobial targets for biofilm-related diseases.}, } @article {pmid33915930, year = {2021}, author = {Szerencsés, B and Gácser, A and Endre, G and Domonkos, I and Tiricz, H and Vágvölgyi, C and Szolomajer, J and Howan, DHO and Tóth, GK and Pfeiffer, I and Kondorosi, É}, title = {Symbiotic NCR Peptide Fragments Affect the Viability, Morphology and Biofilm Formation of Candida Species.}, journal = {International journal of molecular sciences}, volume = {22}, number = {7}, pages = {}, pmid = {33915930}, issn = {1422-0067}, support = {K123952, KKP129924, GINOP 2.3.2-15-2016-00014 Evomer, and GINOP 2.3.2-15-2016-00015 I-KOM//Nemzeti Fejlesztési Ügynökség/ ; Balzan Research Grant to Éva Kondorosi//Balzan Research Grant/ ; }, mesh = {Antifungal Agents/*chemical synthesis/pharmacology ; Biofilms/drug effects ; Candida/*drug effects ; Drug Synergism ; Fluconazole ; HaCaT Cells ; Humans ; Hyphae/drug effects ; Medicago truncatula/*chemistry ; Microbial Sensitivity Tests ; Pore Forming Cytotoxic Proteins/*chemistry/pharmacology ; }, abstract = {The increasing rate of fungal infections causes global problems not only in human healthcare but agriculture as well. To combat fungal pathogens limited numbers of antifungal agents are available therefore alternative drugs are needed. Antimicrobial peptides are potent candidates because of their broad activity spectrum and their diverse mode of actions. The model legume Medicago truncatula produces >700 nodule specific cysteine-rich (NCR) peptides in symbiosis and many of them have in vitro antimicrobial activities without considerable toxicity on human cells. In this work we demonstrate the anticandidal activity of the NCR335 and NCR169 peptide derivatives against five Candida species by using the micro-dilution method, measuring inhibition of biofilm formation with the XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay, and assessing the morphological change of dimorphic Candida species by microscopy. We show that both the N- and C-terminal regions of NCR335 possess anticandidal activity as well as the C-terminal sequence of NCR169. The active peptides inhibit biofilm formation and the yeast-hypha transformation. Combined treatment of C. auris with peptides and fluconazole revealed synergistic interactions and reduced 2-8-fold the minimal inhibitory concentrations. Our results demonstrate that shortening NCR peptides can even enhance and broaden their anticandidal activity and therapeutic potential.}, } @article {pmid33915405, year = {2021}, author = {Qi, X and Wang, S and Jiang, Y and Liu, P and Li, Q and Hao, W and Han, J and Zhou, Y and Huang, X and Liang, P}, title = {Artificial electrochemically active biofilm for improved sensing performance and quickly devising of water quality early warning biosensors.}, journal = {Water research}, volume = {198}, number = {}, pages = {117164}, doi = {10.1016/j.watres.2021.117164}, pmid = {33915405}, issn = {1879-2448}, mesh = {Biofilms ; *Biosensing Techniques ; *Shewanella ; Water Quality ; }, abstract = {A major challenge for devising an electrochemically active biofilm (EAB)-based biosensor for real-time water quality early-warning is the formation of EAB that requires several days to weeks. Besides the onerous and time-consuming preparation process, the naturally formed EABs are intensively concerned as they can hardly deliver repeatable electrical signals even at identical experimental conditions. To address these concerns, this study employed sodium alginate as immobilization agent to encapsulate Shewanella oneidensis MR-1 and prepared EAB for devising a biosensor in a short period of less than 1 h. The artificial EAB were found capable of delivering highly consistent electrical signals with each other when fed with the same samples. Morphology and bioelectrochemical properties of the artificial EAB were investigated to provide interpretations for these findings. Different concentrations of bacteria and alginate in forming the EAB were investigated for their effects on the biosensor's sensitivity. Results suggested that lower concentration of bacteria would be beneficial until it increased to 0.06 (OD660). Concentration of sodium alginate affected the sensitivity as well and 1% was found an optimum amount to serve in the formation of EAB. A long-term operation of the biosensor with artificial EAB for 110 h was performed. Clear warning signals for incoming toxicants were observed over random signal fluctuations. All results suggested that the artificial EAB electrode would support a rapid devised and highly sensitivity biosensor.}, } @article {pmid33913759, year = {2021}, author = {Bandyopadhyay, S and Bhattacharyya, D and Samanta, I and Banerjee, J and Habib, M and Dutta, TK and Dutt, T}, title = {Characterization of Multidrug-Resistant Biofilm-Producing Escherichia coli and Klebsiella pneumoniae in Healthy Cattle and Cattle with Diarrhea.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {11}, pages = {1457-1469}, doi = {10.1089/mdr.2020.0298}, pmid = {33913759}, issn = {1931-8448}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Cattle ; Diarrhea/microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/*drug effects/genetics ; Genes, Bacterial/genetics ; Klebsiella pneumoniae/*drug effects/genetics ; Microbial Sensitivity Tests ; beta-Lactamases/*genetics ; }, abstract = {This study describes comparative occurrence and characterization of multidrug-resistant (MDR) Escherichia coli and Klebsiella pneumoniae (KP) in healthy cattle (HC) and cattle with diarrhea (DC) in India. During 2018-2020, 72 MDR isolates, including 35 E. coli (DC: 27; HC 8) and 37 K. pneumoniae (DC: 34; HC: 3), from 251 rectal swabs (DC: 219; HC: 32) were investigated for extended-spectrum beta-lactamase (ESBL), AmpC type β-lactamase and carbapenemase production, antimicrobial susceptibility profile, biofilm production, and efflux pump activity. Fifty-five MDR isolates were ESBL producers (ESBLPs) (DC: 50; HC: 5) and ESBLPs from DC were coresistant to multiple antibiotics. The blaCTX-M gene (50) was the most frequently detected β-lactamases followed by blaAmpC (22), blaTEM1 (13), blaCMY-6 (6), blaOXA1 (5), blaPER (2), blaDHA, and blaFOX and blaSHV12 (1 each). Plasmid-mediated quinolone resistance determinants qnrB, qnrS, qnrA, and qepA were detected in 18, 16, 2, and 3 isolates, respectively. Twenty three isolates revealed mutation in gyrA and parC genes. Tetracycline-resistance markers tetA, tetB, tetC, and tetE were detected in 33, 10, 3, and 2 isolates, respectively. Only one of the 41 imipenem-resistant isolates harbored blaNDM-5 and two were colistin-resistant. Altogether, 20 MDR isolates were strong biofilm producers and 19 harbored different virulence factors. This is the first ever report from India on the presence of MDR Enterobacteriaceae with resistance to even last-resort antimicrobials in the bovine diarrhea.}, } @article {pmid33912476, year = {2021}, author = {Laulund, AS and Schwartz, F and Trøstrup, H and Thomsen, K and Christophersen, L and Calum, H and Ciofu, O and Høiby, N and Moser, C}, title = {Adjunctive S100A8/A9 Immunomodulation Hinders Ciprofloxacin Resistance in Pseudomonas aeruginosa in a Murine Biofilm Wound Model.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {652012}, pmid = {33912476}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Ciprofloxacin ; Immunomodulation ; Mice ; Microbial Sensitivity Tests ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; *Wound Infection ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa is known to contribute to the pathogenesis of chronic wounds by biofilm-establishment with increased tolerance to host response and antibiotics. The neutrophil-factor S100A8/A9 has a promising adjuvant effect when combined with ciprofloxacin, measured by quantitative bacteriology, and increased anti- and lowered pro-inflammatory proteins. We speculated whether a S100A8/A9 supplement could prevent ciprofloxacin resistance in infected wounds.

METHOD: Full-thickness 2.9cm[2]-necrosis was inflicted on 32 mice. On day 4, P.aeruginosa in seaweed alginate was injected sub-eschar to mimic a mono-pathogenic biofilm. Mice were randomized to receive ciprofloxacin and S100A8/A9 (n=14), ciprofloxacin (n=12) or saline (n=6). Half of the mice in each group were euthanized day 6 and the remaining day 10 post-infection. Mice were treated until sacrifice. Primary endpoint was the appearance of ciprofloxacin resistant P.aeruginosa. The study was further evaluated by genetic characterization of resistance, means of quantitative bacteriology, wound-size and cytokine-production.

RESULTS: Three mice receiving ciprofloxacin monotherapy developed resistance after 14 days. None of the mice receiving combination therapy changed resistance pattern. Sequencing of fluoroquinolone-resistance determining regions in the ciprofloxacin resistant isolates identified two high-resistant strains mutated in gyrA C248T (MIC>32µg/ml) and a gyr B mutation was found in the sample with low level resistance (MIC=3µg/ml). Bacterial densities in wounds were lower in the dual treated group compared to the placebo group on both termination days.

CONCLUSION: This study supports the ciprofloxacin augmenting effect and indicates a protective effect in terms of hindered ciprofloxacin resistance of adjuvant S100A8/A9 in P.aeruginosa biofilm infected chronic wounds.}, } @article {pmid33911349, year = {2020}, author = {Tilakchand, M and Hegde, S and Naik, B}, title = {Evaluation of the efficacy of a novel antibiotic-steroid paste versus conventionally used intracanal antibiotic pastes and irrigating solutions against a 3-week-old biofilm of Enterococcus faecalis.}, journal = {Journal of conservative dentistry : JCD}, volume = {23}, number = {5}, pages = {436-440}, pmid = {33911349}, issn = {0972-0707}, abstract = {INTRODUCTION: Intracanal medicaments have been used during endodontic regenerative procedures to eradicate endodontic pathogens.

AIMS: The aim of our study was (1) to evaluate the antimicrobial efficacy of a novel antibiotic-steroid paste over the regularly used calcium hydroxide (Ca (OH)2), double antibiotic paste (DAP), and modified triple antibiotic paste (M-TAP) and (2) to check the antimicrobial efficacy of irrigating solutions, Chlorhexidine (CHX), and sodium hypochlorite (NaOCl) against a 3-week-old Enterococcus faecalis (E. faecalis) biofilm.

MATERIALS AND METHODS: A total of 112 human extracted teeth were contaminated with E. faecalis for a period of 21 days. A novel antibiotic-steroid paste, Ca (OH) 2, DAP, M-TAP, and a placebo were placed inside the canal, sealed, and incubated in an aerobic environment at 37°C. For irrigating solutions, each prepared sample was immersed in 1 ml of sterile saline for 1 min, followed by irrigating and immersion with 1.5% NaOCl and 2% CHX for 5 min. An antimicrobial assessment was performed at the end of 2 days and 7 days, with seven teeth from each group, for each time interval. Dentin debris collected was transferred to the respective medium for culture. After 24 h, colonies were counted using classical bacterial counting technique as colony-forming units.

RESULTS: Statistical analysis revealed that the novel antibiotic-steroid paste showed a statistically insignificant difference when compared to DAP, which had the highest antimicrobial properties.

CONCLUSION: This novel functional paste has antimicrobial efficacy comparable with that of DAP.}, } @article {pmid33910142, year = {2021}, author = {Wang, Y and Lai, CY and Wu, M and Song, Y and Hu, S and Yuan, Z and Guo, J}, title = {Roles of Oxygen in Methane-dependent Selenate Reduction in a Membrane Biofilm Reactor: Stimulation or Suppression.}, journal = {Water research}, volume = {198}, number = {}, pages = {117150}, doi = {10.1016/j.watres.2021.117150}, pmid = {33910142}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; *Methane ; Oxidation-Reduction ; *Oxygen ; RNA, Ribosomal, 16S/genetics ; Selenic Acid ; }, abstract = {Although methane (CH4) has been proven to be able to serve as an electron donor for bio-reducing various oxidized contaminants (e.g., selenate (SeO4[2-])), little is known regarding the roles of oxygen in methane-based reduction processes. Here, a methane-based membrane biofilm reactor (MBfR) was established for evaluating the effects of oxygen supply rates on selenate reduction performance and microbial communities. The oxygen supply rate played a dual role (stimulatory or suppressive effect) in selenate reduction rates, depending on the presence or absence of dissolved oxygen (DO). Specifically, selenate reduction rate was substantially enhanced when an appropriate oxygen rate (e.g., 12 to 184 mg/L[.]d in this study) was supplied but with negligible DO. The highest selenate reduction rate (up to 34 mg-Se/L[.]d) was obtained under an oxygen supply rate of 184 mg/L[.]d. In contrast, excessive oxygen supply rate (626 mg/L[.]d) would significantly suppress selenate reduction rate under DO level of 3 mg/L. Accordingly, though the high oxygen supply rate (626 mg/L[.]d) would promote the expression of pmoA (5.9 × 10[9] copies g[-1]), the expression level of narG (a recognized gene to mediate selenate reduction) would be significantly downregulated (6.1 × 10[9] copies g[-1]), thus suppressing selenate reduction. In contrast, the expression of narG gene significantly increased to 2.8 × 10[10] copies g[-1], and the expression of pmoA gene could still maintain at 1.1 × 10[9] copies g[-1] under an oxygen supply rate of 184 mg/L[.]d. High-throughput sequencing targeting 16S rRNA gene, pmoA, and narG collectively suggested Methylocystis acts as the major aerobic methanotroph, in synergy with Arthrobacter and Variovorax which likely jointly reduce selenate to selenite (SeO3[2-]), and further to elemental selenium (Se[0]). Methylocystis was predominant in the biofilm regardless of variations of oxygen supply rates, while Arthrobacter and Variovorax were sensitive to oxygen fluctuation. These findings provide insights into the effects of oxygen on methane-dependent selenate reduction and suggest that it is feasible to achieve a higher selenate removal by regulating oxygen supply rates.}, } @article {pmid33910119, year = {2021}, author = {Lu, S and Wang, Q and Gao, M and Zhao, C and She, Z and Zhao, Y and Jin, C and Guo, L}, title = {Effect of aerobic/anoxic duration on the performance, microbial activity and microbial community of sequencing batch biofilm reactor treating synthetic mariculture wastewater.}, journal = {Bioresource technology}, volume = {333}, number = {}, pages = {125198}, doi = {10.1016/j.biortech.2021.125198}, pmid = {33910119}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; Nitrogen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The effect of aerobic/anoxic duration on the performance, microbial community and enzymatic activity of sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater. The microbial oxygen uptake rate and nitrifying rate gradually decreased with the aerobic/anoxic duration from 120/210 to 30/300 min, whereas the nitrite reducing rate and nitrate reducing rate had the opposite results. The activities of dehydrogenase, ammonia monooxygenase and nitrite oxidoreductase gradually decreased with the aerobic/anoxic duration from 120/210 to 30/300 min, but the activities of nitrate reductase and nitrite reductase had a gradual increment. The microbial nitrogen removal rates had similar changing trends to their corresponding enzymatic activities at different aerobic/anoxic duration. The variation of aerobic/anoxic duration obviously affected the microbial richness and diversity of SBBR. The co-occurrence, keystone taxa and significant difference of microbial community had some changes with the aerobic/anoxic duration from 120/210 to 30/300 min.}, } @article {pmid33909550, year = {2021}, author = {Wang, S and Xiang, D and Tian, F and Ni, M}, title = {Lipopolysaccharide from biofilm-forming Pseudomonas aeruginosa PAO1 induces macrophage hyperinflammatory responses.}, journal = {Journal of medical microbiology}, volume = {70}, number = {4}, pages = {}, pmid = {33909550}, issn = {1473-5644}, mesh = {Animals ; Biofilms/*growth & development ; Blotting, Western ; Cytokines/analysis ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique ; Humans ; Lipopolysaccharides/*pharmacology ; Macrophages/*drug effects/pathology ; Mice ; Microscopy, Fluorescence ; Pseudomonas aeruginosa/*chemistry/physiology ; RAW 264.7 Cells ; RNA, Bacterial/genetics/isolation & purification ; THP-1 Cells ; }, abstract = {Introduction. Macrophages polarization is essential in infection control. Llipopolysaccharide (LPS) plays an essential role in host innate immune system-pathogen interaction. The LPS structure of Pseudomonas aeruginosa modifies in the adaptation of this pathogen to biofilm-related chronic infection.Gap statement. There have been several studies on LPS induced polarization of human and mouse macrophages with different results. And it was reported that the lipid A structure of the LPS derived from biofilm-forming Pseudomonas aeruginosa strain PAO1 was modified.Aim. This study aimed to investigate the effect and the involved pathway of LPS from biofilm-forming PAO1 on human and murine macrophage polarization.Methodology. LPS was isolated from biofilm-forming and planktonic PAO1 and quantified. Then the LPS was added to PMA-differentiated human macrophage THP-1 cells and Raw264.7 murine macrophage cells. The expression of iNOS, Arg-1, IL4, TNF-α, CCL3, and CCL22 was analysed in the different cell lines. The expression of TICAM-1 and MyD88 in human THP-1 macrophages was quantified by Western blot. PAO1 infected macrophages at different polarization states, and the intracellular bacterial growth in macrophages was evaluated.Results. LPS from biofilm-forming PAO1 induced more marked hyperinflammatory responses in THP-1 and Raw264.7 macrophages than LPS derived from planktonic PAO1, and these responses were related to the up-regulation of MyD88. Intracellular growth of PAO1 was significantly increased in THP-1 macrophages polarized by LPS from biofilm-forming PAO1, but decreased both in THP-1 and Raw264.7 macrophages polarized by LPS from planktonic PAO1.Conclusion. The presented in vitro study indicates that LPS derived from biofilm-forming PAO1 induces enhanced M1 polarization in human and murine macrophage cell lines than LPS from planktonic PAO1.}, } @article {pmid33908759, year = {2021}, author = {Thorn, CR and Raju, D and Lacdao, I and Gilbert, S and Sivarajah, P and Howell, PL and Prestidge, CA and Thomas, N}, title = {Protective Liquid Crystal Nanoparticles for Targeted Delivery of PslG: A Biofilm Dispersing Enzyme.}, journal = {ACS infectious diseases}, volume = {7}, number = {8}, pages = {2102-2115}, doi = {10.1021/acsinfecdis.1c00014}, pmid = {33908759}, issn = {2373-8227}, support = {MOP 43998//CIHR/Canada ; FDN154327//CIHR/Canada ; }, mesh = {Animals ; Biofilms ; Caenorhabditis elegans ; *Liquid Crystals ; *Nanoparticles ; Pseudomonas aeruginosa ; }, abstract = {The glycoside hydrolase, PslG, attacks and degrades the dominant Psl polysaccharide in the exopolymeric substance (EPS) matrix of Pseudomonas aeruginosa biofilms and is a promising therapy to potentiate the effect of antibiotics. However, the need for coadministration with an antibiotic and the potential susceptibility of PslG to proteolysis highlights the need for an effective delivery system. Here, we compared liposomes versus lipid liquid crystal nanoparticles (LCNPs) loaded with PslG and tobramycin as potential formulation approaches to (1) protect PslG from proteolysis, (2) trigger the enzyme's release in the presence of bacteria, and (3) improve the total antimicrobial effect in vitro and in vivo in a Caenorhabditis elegans infection model. LCNPs were an effective formulation strategy for PslG and tobramycin that better protected the enzyme against proteolysis, triggered and sustained the release of PslG, improved the antimicrobial effect by 10-100-fold, and increased the survival of C. elegans infected with P. aeruginosa. Digestible LCNPs had the advantage of triggering the enzyme's release in the presence of bacteria. However, compared to nondigestible LCNPs, negligible differences arose between the LCNPs' ability to protect PslG from proteolysis and potentiate the antimicrobial activity in combination with tobramycin. In C. elegans, the improved antimicrobial efficacy was comparable to tobramycin-LCNPs, although the PslG + tobramycin-LCNPs achieved a greater than 10-fold reduction in bacteria compared to the unformulated combination. Herewith, LCNPs are showcased as a promising protective delivery system for novel biofilm dispersing enzymes combined with antibiotics, enabling infection-directed therapy and improved performance.}, } @article {pmid33908128, year = {2021}, author = {Mahto, KU and Das, S}, title = {Microscopic techniques to evaluate the biofilm formation ability of a marine bacterium Pseudomonas aeruginosa PFL-P1 on different substrata.}, journal = {Microscopy research and technique}, volume = {84}, number = {10}, pages = {2451-2461}, doi = {10.1002/jemt.23799}, pmid = {33908128}, issn = {1097-0029}, support = {BT/PR17390/BCE/8/1158/2016//Department of Biotechnology, Ministry of Science and Technology/ ; }, mesh = {Bacteria ; *Biofilms ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Pseudomonas aeruginosa ; }, abstract = {Biofilm formation in bacteria is strongly affected by the nature of substrata. Different substrata such as glass, polystyrene, steel, ceramic, and rubber were used to assess the biofilm forming ability of a marine bacterium Pseudomonas aeruginosa PFL-P1 using a scanning electron microscope (SEM), atomic force microscope (AFM), and confocal laser scanning microscope (CLSM). The bacterium formed dense biofilms with varied aggregation on different substrata. SEM study revealed small rod-shaped cells with diverse arrangements within the biofilms on all the substrata under study. The AFM study revealed the highest roughness of 545 nm on the ceramic substratum. The biofilms formed on ceramic substratum were characterized with maximum roughness (742 nm), maximum peak height (1,480 nm), and maximum arithmetic mean height (611 nm), significantly higher than all the other substrata (p < .05). AFM studies confirmed that P. aeruginosa PFL-P1 exhibited biofilm heterogeneity on all the substrata. The CLSM study indicated a higher fraction of nucleic acids to α-polysaccharides ratio in the biofilms. COMSTAT analysis revealed the highest biofilm biomass of ~18 μm[3] /μm[2] on the ceramic substratum. The maximum biofilm thickness of ~50 μm in the native state on the ceramic substratum was significantly higher than glass (p = .0015), polystyrene (p = .0001), steel (p = .0035), and rubber substrata (p = .0001). The higher surface roughness of ceramic substratum is accountable for more area for colonization, as evident from higher biomass and thickness of the biofilm. This study provides insight into the substratum properties, which modulate the biofilm forming ability in bacteria.}, } @article {pmid33907676, year = {2021}, author = {Fathi, F and Sadrnia, M and Arjomandzadegan, M and Mohajerani, HR}, title = {In vitro and in vivo evaluation of antibacterial and anti-biofilm properties of five ethnomedicinal plants against oral bacteria by TEM.}, journal = {Avicenna journal of phytomedicine}, volume = {11}, number = {2}, pages = {180-189}, pmid = {33907676}, issn = {2228-7930}, abstract = {OBJECTIVE: The aim of the present study was to investigate antibacterial and antibiofilm activity of a few medicinal plants against oral bacteria.

MATERIALS AND METHODS: Salvia officinalis, Lippie citriodora, Mentha piperita, Echinacea purpurea and Matricaria chamomilla were extracted. Isolates from oral cavity were identified by microbiological and molecular methods. Minimum inhibitory concentration and minimum bactericidal concentration were determined by Broth microdilution method. The anti-biofilm activity of essential oils and extracts investigated and as a mixture by Broth dilution method. Toxicity of the herbal mixture was assayed by in Wistar rats treated with intradermal injection. Wound healing properties of the herbal mixture against infected wounds on the back of the rats were investigated. Anti-biofilm activity was investigated on tooth surfaces. Bacterial structure changes and fine- structure study were performed by light microscopy and Transmission electron microscopy.

RESULTS: The lowest MIC and MBC for the plant mixtures was 0.0002 mg/ml belonged to Streptococcus pyogenes and the highest values (0.025 mg/ml) belonged to Eikenella corrodens. The essential oils of S.officinalis, L.citriodora and M.piperita, but not E.purpurea and M.chamomilla extracts, were able to remove the biofilms created by the studied bacteria. The herbal mixture was able to completely heal the wound skin of rats in 21 days (p<0.05 compared to control). The mixture was able to decompose the teeth biofilm in 45 seconds. The results of light and electron microscopy showed that the bacterial structure exposed to the herbal mixture was deformed.

CONCLUSION: It was concluded that the essential oils of S.officinalis, L.citriodora and M.piperita had significant effects on inhibition of oral bacteria biofilm formation.}, } @article {pmid33904608, year = {2021}, author = {Loza-Correa, M and Yousuf, B and Ramirez-Arcos, S}, title = {Staphylococcus epidermidis undergoes global changes in gene expression during biofilm maturation in platelet concentrates.}, journal = {Transfusion}, volume = {61}, number = {7}, pages = {2146-2158}, doi = {10.1111/trf.16418}, pmid = {33904608}, issn = {1537-2995}, support = {//Health Canada/ ; //Genome Canada/ ; //Canadian Blood Services/ ; }, mesh = {Bacteremia/*microbiology ; Base Sequence ; Biofilms/*growth & development ; Blood Platelets/*microbiology ; Blood Preservation ; Drug Resistance, Microbial/genetics ; *Gene Expression Regulation, Bacterial ; Gene Ontology ; Humans ; RNA, Bacterial/biosynthesis/blood ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/microbiology ; Staphylococcus epidermidis/drug effects/*genetics/growth & development/isolation & purification ; Transcriptome ; }, abstract = {BACKGROUND: Staphylococcus epidermidis forms surface-attached aggregates (biofilms) when grown in platelet concentrates (PCs). Comparative transcriptome analyses were undertaken to investigate differential gene expression of S. epidermidis biofilms grown in PCs.

STUDY DESIGN AND METHODS: Two S. epidermidis strains isolated from human skin (AZ22 and AZ39) and one strain isolated from contaminated PCs (ST02) were grown in glucose-supplemented Trypticase Soy Broth (TSBg) and PCs. RNA was extracted and sequenced using Illumina HiSeq. Differential expression analysis was done using DESeq, and significantly differentially expressed genes (DEGs) were selected. DEGs were subjected to Kyoto encyclopedia of genes and genomes and Gene Ontology analyses. Differential gene expression was validated with quantitative reverse transcription-PCR.

RESULTS: A total of 436, 442, and 384 genes were expressed in AZ22, AZ39, and ST02, respectively. DEG analysis showed that 170, 172, and 117 genes were upregulated in PCs in comparison to TSBg, whereas 120, 135, and 89 genes were downregulated (p < .05) in mature biofilms of AZ22, AZ39, and ST02, respectively. Twenty-seven DEGs were shared by all three strains. While 76 DEGs were shared by AZ22 and AZ39, only 34 and 21 DEGs were common between ST02, and AZ22 and AZ39, respectively. Significant transcriptional expression changes were observed in genes involved in platelet-bacteria interaction, biofilm formation, production of virulence factors, and resistance to antimicrobial peptides and antibiotics.

CONCLUSION: Differential gene expression in S. epidermidis is triggered by the stressful PC storage environment. Upregulation of virulence and antimicrobial resistance genes could have clinical implications for transfusion patients.}, } @article {pmid33904369, year = {2021}, author = {Silva, V and Miranda, C and Bezerra, M and Antão, HS and Guimarães, J and Prada, J and Pires, I and Maltez, L and Pereira, JE and Capelo, JL and Igrejas, G and Poeta, P}, title = {Anti-biofilm activity of dalbavancin against methicillin-resistant Staphylococcus aureus (MRSA) isolated from human bone infection.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {33}, number = {7}, pages = {469-475}, doi = {10.1080/1120009X.2021.1911518}, pmid = {33904369}, issn = {1973-9478}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Bone Diseases, Infectious/drug therapy ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics ; Microbial Sensitivity Tests ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects ; Teicoplanin/*analogs & derivatives/pharmacology/therapeutic use ; }, abstract = {The presence of methicillin-resistant Staphylococcus aureus (MRSA) in bone infections difficults its treatment and is a sign of concern. The aim of this study was to evaluate in vitro activity of dalbavancin on pre-established adhered cells and 24 h old biofilms of MRSA strains isolated from a human bone infection. Thirty-three MRSA were isolated from osteomyelitis episodes. The antimicrobial susceptibility of these strains was assessed by the Kirby-Bauer disc diffusion method and the presence of resistance genes was screened by PCR. MRSA planktonic minimum inhibitory concentration and minimum bactericidal concentration were assessed. Minimum biofilm eradication concentration (MBEC) was performed by the microtiter biofilm formation assay. All 33 MRSA strains were classified as multidrug-resistant strains and susceptible to dalbavancin. Dalbavancin inhibited the growth of 54.6% and 52% of strains at the concentrations of 0.05 µg/mL and 1 µg/mL, respectively. The MBEC values up to 0.4 µg/mL demonstrated that dalbavancin was active against most strains in pre-established adhered cells and 24 h old biofilms. The current results show that dalbavancin is active against adhered cells and biofilms in vitro, suggesting that this antimicrobial agent may be an option for the treatment of bone infections caused by MRSA.}, } @article {pmid33903615, year = {2021}, author = {Paluch, E and Szperlik, J and Lamch, Ł and Wilk, KA and Obłąk, E}, title = {Biofilm eradication and antifungal mechanism of action against Candida albicans of cationic dicephalic surfactants with a labile linker.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {8896}, pmid = {33903615}, issn = {2045-2322}, mesh = {*Antifungal Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Microbial Sensitivity Tests ; *Surface-Active Agents/chemistry/pharmacology ; }, abstract = {Our research aims to expand the knowledge on relationships between the structure of cationic dicephalic surfactants-N,N-bis[3,3_-(dimethylamine)propyl]alkylamide dihydrochlorides and N,N-bis[3,3_-(trimethylammonio)propyl]alkylamide dibromides (alkyl: n-C9H19, n-C11H23, n-C13H27, n-C15H31)-and their antifungal mechanism of action on Candida albicans. The mentioned groups of amphiphilic substances are characterized by the presence of a weak, hydrochloride cationic center readily undergoing deprotonation, as well as a stable, strong quaternary ammonium group and alkyl chains capable of strong interactions with fungal cells. Strong fungicidal properties and the role in creation and eradication of biofilm of those compounds were discussed in our earlier works, yet their mechanism of action remained unclear. It was shown that investigated surfactants induce strong oxidative stress and cause increase in cell membrane permeability without compromising its continuity, as indicated by increased potassium ion (K[+]) leakage. Thus experiments carried out on the investigated opportunistic pathogen indicate that the mechanism of action of the researched surfactants is different than in the case of the majority of known surfactants. Results presented in this paper significantly broaden the understanding on multifunctional cationic surfactants and their mechanism of action, as well as suggest their possible future applications as surface coating antiadhesives, fungicides and antibiofilm agents in medicine or industry.}, } @article {pmid33902713, year = {2020}, author = {Maus, I and Klocke, M and Derenkó, J and Stolze, Y and Beckstette, M and Jost, C and Wibberg, D and Blom, J and Henke, C and Willenbücher, K and Rumming, M and Rademacher, A and Pühler, A and Sczyrba, A and Schlüter, A}, title = {Impact of process temperature and organic loading rate on cellulolytic / hydrolytic biofilm microbiomes during biomethanation of ryegrass silage revealed by genome-centered metagenomics and metatranscriptomics.}, journal = {Environmental microbiome}, volume = {15}, number = {1}, pages = {7}, pmid = {33902713}, issn = {2524-6372}, support = {03SF0440//Bundesministerium für Bildung und Forschung/ ; }, abstract = {BACKGROUND: Anaerobic digestion (AD) of protein-rich grass silage was performed in experimental two-stage two-phase biogas reactor systems at low vs. increased organic loading rates (OLRs) under mesophilic (37 °C) and thermophilic (55 °C) temperatures. To follow the adaptive response of the biomass-attached cellulolytic/hydrolytic biofilms at increasing ammonium/ammonia contents, genome-centered metagenomics and transcriptional profiling based on metagenome assembled genomes (MAGs) were conducted.

RESULTS: In total, 78 bacterial and archaeal MAGs representing the most abundant members of the communities, and featuring defined quality criteria were selected and characterized in detail. Determination of MAG abundances under the tested conditions by mapping of the obtained metagenome sequence reads to the MAGs revealed that MAG abundance profiles were mainly shaped by the temperature but also by the OLR. However, the OLR effect was more pronounced for the mesophilic systems as compared to the thermophilic ones. In contrast, metatranscriptome mapping to MAGs subsequently normalized to MAG abundances showed that under thermophilic conditions, MAGs respond to increased OLRs by shifting their transcriptional activities mainly without adjusting their proliferation rates. This is a clear difference compared to the behavior of the microbiome under mesophilic conditions. Here, the response to increased OLRs involved adjusting of proliferation rates and corresponding transcriptional activities. The analysis led to the identification of MAGs positively responding to increased OLRs. The most outstanding MAGs in this regard, obviously well adapted to higher OLRs and/or associated conditions, were assigned to the order Clostridiales (Acetivibrio sp.) for the mesophilic biofilm and the orders Bacteroidales (Prevotella sp. and an unknown species), Lachnospirales (Herbinix sp. and Kineothrix sp.) and Clostridiales (Clostridium sp.) for the thermophilic biofilm. Genome-based metabolic reconstruction and transcriptional profiling revealed that positively responding MAGs mainly are involved in hydrolysis of grass silage, acidogenesis and / or acetogenesis.

CONCLUSIONS: An integrated -omics approach enabled the identification of new AD biofilm keystone species featuring outstanding performance under stress conditions such as increased OLRs. Genome-based knowledge on the metabolic potential and transcriptional activity of responsive microbiome members will contribute to the development of improved microbiological AD management strategies for biomethanation of renewable biomass.}, } @article {pmid33900109, year = {2021}, author = {Nag, S and Biswas, A and Chattopadhyay, D and Bhattacharyya, M}, title = {Protein-stabilized silver nanoparticles encapsulating gentamycin for the therapy of bacterial biofilm infections.}, journal = {Nanomedicine (London, England)}, volume = {16}, number = {10}, pages = {801-818}, doi = {10.2217/nnm-2020-0451}, pmid = {33900109}, issn = {1748-6963}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacterial Infections ; Biofilms ; Gentamicins ; Humans ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Silver ; }, abstract = {Aim: An antibiotic-conjugated protein-stabilized nanoparticle hybrid system was developed to combat the challenges faced during the treatment of drug-resistant bacterial biofilm-associated infections. Materials & methods: Biocompatible silver nanoparticles were synthesized using intracellular protein and gentamycin was attached. The resulting nanohybrid was characterized and its antibacterial efficiency was assessed against Gram-positive, Gram-negative and drug-resistant bacteria. Results: Spectroscopic and electron microscopic analysis revealed that the nanoparticles were spherical with a diameter of 2-6 nm. Red-shifting of the surface plasmon peak and an increase in hydrodynamic diameter confirmed attachment of gentamycin. The nanohybrid exhibited antibacterial efficiency against a range of bacteria with the ability to inhibit and disrupt bacterial biofilm. Conclusion: A unique nanohybrid was designed that has potential to be used to control drug-resistant bacterial infections in the future.}, } @article {pmid33899251, year = {2021}, author = {Gomes, SC and Fachin, S and da Fonseca, JG and Angst, PDM and Lamers, ML and da Silva, ISB and Nunes, LN}, title = {Dental biofilm of symptomatic COVID-19 patients harbours SARS-CoV-2.}, journal = {Journal of clinical periodontology}, volume = {48}, number = {7}, pages = {880-885}, pmid = {33899251}, issn = {1600-051X}, support = {//The authors and the Post-graduation Program at the Dental Faculty of the Federal University were responsible for funding./ ; }, mesh = {Aged ; Biofilms ; *COVID-19 ; Female ; Humans ; Male ; RNA, Viral ; Real-Time Polymerase Chain Reaction ; *SARS-CoV-2 ; Viral Load ; }, abstract = {AIMS: SARS-CoV-2 RNA has been recovered from different sites in the human body, including the mouth. The present study aimed to investigate the presence of SARS-CoV-2 RNA in the dental biofilm of symptomatic patients who tested positive in nasopharyngeal and oropharyngeal (NASO/ORO) samples.

MATERIALS & METHODS: An observational clinical study of individuals with flu-like symptoms was conducted between July and September 2020. Dental biofilm (BIO) samples were collected and analysed using real-time quantitative polymerase chain reaction (RT-qPCR) to determine the virus's presence.

RESULTS: Seventy participants (40 ± 9.8 years of age, 71.4% female) tested positive for SARS-CoV-2 RNA in NASO/ORO samples and were included in the study. Among them, 13 tested positive in BIO samples (18.6%; 95% CI: [9.5, 27.7]). The median and interquartile range of cycle quantification (Cq) for NASO/ORO and BIO samples were 15.9 [6.9] and 35.9 [4.0] (p = .001), respectively. BIO-positive participants showed a higher virus load in NASO/ORO samples (p = .012) than those testing negative (Cq = 20.4 [6.1]).

CONCLUSIONS: Dental biofilms from symptomatic COVID-19 patients harbour SARS-CoV-2 RNA and might be a potential reservoir with an essential role in COVID-19 transmission.}, } @article {pmid33898970, year = {2021}, author = {Khan, MF and Saleem, D and Murphy, CD}, title = {Regulation of Cunninghamella spp. biofilm growth by tryptophol and tyrosol.}, journal = {Biofilm}, volume = {3}, number = {}, pages = {100046}, pmid = {33898970}, issn = {2590-2075}, abstract = {Fungi belonging to the genus Cunninghamella are often used as microbial models of mammalian metabolism owing to their ability to transform a range of xenobiotic compounds. Furthermore, under specific growth conditions species such as Cunninghamella elegans and Cunninghamella echinulata grow as biofilms enabling a convenient semi-continuous production of valuable drug metabolites. However, the molecular mechanism of biofilm regulation is not understood, thus controlling biofilm thickness limits the productive applications of it. In this paper we describe the identification of two molecules, tyrosol and tryptophol, that were identified in C. blakesleeana cultures, but not in C. elegans and C. echinulata. The molecules are known quorum sensing molecules (QSMs) in yeast and their potential role in Cunninghamella biofilm regulation was explored. Both were present in higher concentrations in C. blakesleeana planktonic cultures compared with biofilms; they inhibited the growth of the fungus on agar plates and selectively inhibited biofilm growth in liquid cultures. The molecules had a comparatively minor impact on the biofilm growth of C. elegans and C. echinulata and on the growth of these fungi on agar plates. Finally, when exogenous tyrosol or tryptophol was added to previously grown C. blakesleeana biofilm, detachment was visible and new additional planktonic culture was measured, confirming that these molecules specifically regulate biofilm growth in this fungus.}, } @article {pmid33897696, year = {2021}, author = {Versey, Z and da Cruz Nizer, WS and Russell, E and Zigic, S and DeZeeuw, KG and Marek, JE and Overhage, J and Cassol, E}, title = {Biofilm-Innate Immune Interface: Contribution to Chronic Wound Formation.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {648554}, pmid = {33897696}, issn = {1664-3224}, mesh = {Animals ; Bacteria/classification/growth & development/immunology ; Biofilms/*growth & development ; Chronic Disease ; Diabetic Foot/*immunology/microbiology ; Humans ; Immunity, Innate/*immunology/physiology ; Microbiota/*immunology/physiology ; Models, Immunological ; Wound Healing/*immunology/physiology ; }, abstract = {Delayed wound healing can cause significant issues for immobile and ageing individuals as well as those living with co-morbid conditions such as diabetes, cardiovascular disease, and cancer. These delays increase a patient's risk for infection and, in severe cases, can result in the formation of chronic, non-healing ulcers (e.g., diabetic foot ulcers, surgical site infections, pressure ulcers and venous leg ulcers). Chronic wounds are very difficult and expensive to treat and there is an urgent need to develop more effective therapeutics that restore healing processes. Sustained innate immune activation and inflammation are common features observed across most chronic wound types. However, the factors driving this activation remain incompletely understood. Emerging evidence suggests that the composition and structure of the wound microbiome may play a central role in driving this dysregulated activation but the cellular and molecular mechanisms underlying these processes require further investigation. In this review, we will discuss the current literature on: 1) how bacterial populations and biofilms contribute to chronic wound formation, 2) the role of bacteria and biofilms in driving dysfunctional innate immune responses in chronic wounds, and 3) therapeutics currently available (or underdevelopment) that target bacteria-innate immune interactions to improve healing. We will also discuss potential issues in studying the complexity of immune-biofilm interactions in chronic wounds and explore future areas of investigation for the field.}, } @article {pmid33897670, year = {2021}, author = {Jiang, F and Lei, T and Wang, Z and He, M and Zhang, J and Wang, J and Zeng, H and Chen, M and Xue, L and Ye, Q and Pang, R and Wu, S and Gu, Q and Ding, Y and Wu, Q}, title = {A Novel Gene vp0610 Negatively Regulates Biofilm Formation in Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {656380}, pmid = {33897670}, issn = {1664-302X}, abstract = {Vibrio parahaemolyticus is an important foodborne pathogen and its biofilm formation ability facilitates its colonization and persistence in foods by protecting it from stresses including environmental variation and antibiotic exposure. Several important proteins are involved in biofilm formation; however, the identity and function of many remain unknown. In this study, we discovered a hypothetical protein, VP0610 that negatively regulates biofilm formation in Vibrio parahaemolyticus, and we found that the loss of vp0610 typically results in pleiotropic phenotypes that contribute toward promoting biofilm formation, including significantly increased insoluble exopolysaccharide production and swimming motility, decreased soluble exopolysaccharide production, and decreased bis-(3'-5')-cyclic dimeric guanosine monophosphate production. Pull-down assays revealed that VP0610 can interact with 180 proteins, some of which (Hfq, VP0710, VP0793, and CyaA) participate in biofilm formation. Moreover, deleting vp0610 enhanced the expression of genes responsible for biofilm component (flaE), the sugar phosphotransferase system (PTS) EIIA component (vp0710 and vp0793), and a high-density regulator of quorum sensing (opaR), while reducing the expression of the bis-(3'-5')-cyclic dimeric guanosine monophosphate degradation protein (CdgC), resulting in faster biofilm formation. Taken together, our results indicate that vp0610 is an integral member of the key biofilm regulatory network of V. parahaemolyticus that functions as a repressor of biofilm formation.}, } @article {pmid33897636, year = {2021}, author = {Abdullah, and Asghar, A and Algburi, A and Huang, Q and Ahmad, T and Zhong, H and Javed, HU and Ermakov, AM and Chikindas, ML}, title = {Anti-biofilm Potential of Elletaria cardamomum Essential Oil Against Escherichia coli O157:H7 and Salmonella Typhimurium JSG 1748.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {620227}, pmid = {33897636}, issn = {1664-302X}, abstract = {Foodborne pathogens, microbial recurrent infections, and antibiotic resistance have driven researchers to explore natural compounds as safe alternative antimicrobials. In this study, the chemical profile, antimicrobial, and mutagenic activities of the Elletaria cardamomum essential oil were investigated. GC-MS analysis identified the major bioactive components as α-terpinyl acetate, 1,8-cineole, linalool acetate, and sabinene, at concentrations of 34.95, 25.30, 8.13, and 5.48% respectively, of the essential oil's content. Regarding antimicrobial activity, the minimum inhibitory concentration of green cardamom essential oil was 1% against Escherichia coli O157:H7 and Pseudomonas aeruginosa ATCC 14213. Green cardamom essential oil, when used at concentrations of 0.015, 0.031, 0.062, and 0.125% (v/v) prevented biofilm formation of Escherichia coli O157:H7 by 64.29, 65.98, 70.41, and 85.59%, respectively. Furthermore, these concentrations inhibited 6.13, 45.50, 49.45, and 100%, respectively, of the Salmonella Typhimurium JSG 1748 biofilm. A mutagenicity assay confirmed that green cardamom essential oil has no demonstrable mutagenic activity against the tested strains. The study's findings suggest that green cardamom derived bioactive compounds are safe organic antimicrobials, effective in controlling biofilm formation by Gram-negative pathogens. Moreover, such compounds could possibly be used in the food industry (e.g., bakery, dairy, meat, and other food products) as a safe alternative to chemical preservatives (antimicrobials) to enhance shelf life by improving the antimicrobial status while at the same time imparting a pleasant and appealing aroma for consumers.}, } @article {pmid33897624, year = {2021}, author = {Benda, M and Schulz, LM and Stülke, J and Rismondo, J}, title = {Influence of the ABC Transporter YtrBCDEF of Bacillus subtilis on Competence, Biofilm Formation and Cell Wall Thickness.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {587035}, pmid = {33897624}, issn = {1664-302X}, abstract = {Bacillus subtilis develops genetic competence for the uptake of foreign DNA when cells enter stationary phase and a high cell density is reached. These signals are integrated by the competence transcription factor ComK, which is subject to transcriptional, post-transcriptional and post-translational regulation. Many proteins are involved in the development of competence, both to control ComK activity and to mediate DNA uptake. However, for many proteins, the precise function they play in competence development is unknown. In this study, we assessed whether proteins required for genetic transformation play a role in the activation of ComK or rather act downstream of competence gene expression. While these possibilities could be distinguished for most of the tested factors, we assume that two proteins, PNPase and the transcription factor YtrA, are required both for full ComK activity and for the downstream processes of DNA uptake and integration. Further analyses of the role of the transcription factor YtrA for the competence development revealed that the overexpression of the YtrBCDEF ABC transporter in the ytrA mutant causes the loss of genetic competence. Moreover, overexpression of this ABC transporter also affects biofilm formation. Since the ytrGABCDEF operon is naturally induced by cell wall-targeting antibiotics, we tested the cell wall properties upon overexpression of the ABC transporter and observed an increased thickness of the cell wall. The composition and properties of the cell wall are important for competence development and biofilm formation, suggesting that the observed phenotypes are the result of the increased cell wall thickness as an outcome of YtrBCDEF overexpression.}, } @article {pmid33895670, year = {2021}, author = {Jiang, H and Yang, P and Wang, Z and Ren, S and Qiu, J and Liang, H and Peng, Y and Li, X and Zhang, Q}, title = {Efficient and advanced nitrogen removal from mature landfill leachate via combining nitritation and denitritation with Anammox in a single sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {333}, number = {}, pages = {125138}, doi = {10.1016/j.biortech.2021.125138}, pmid = {33895670}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Nitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; *Water Pollutants, Chemical ; }, abstract = {A novel combined partial nitrification-Anammox and partial denitrification-Anammox (PnA/PdA) single sequencing batch biofilm reactor (SBBR) was established to realize efficient and advanced nitrogen removal from mature landfill leachate with low biodegradability. Nitrogen removal rate and nitrogen removal efficiency were increased to 2.83 ± 0.06 kgN/(m[3]∙d) and 98.6 ± 0.2% by stepwise increase of dissolved oxygen (DO, from 0.5 to 3.5 mg/L) and continuous carbon source feeding. Comparable activities of ammonia oxidation bacteria and Anammox bacteria were realized during aerobic period. More organic carbon was redirected from complete denitrification to partial denitrification during anoxic period. The main pathway PnA jointly synergized with PdA, which contributed to 76.04% and 19.44% nitrogen removal, respectively. Nitrosomonas, Thauera, and Kuenenia dominated in floc sludge (0.78%, 5.38%, and 1.14%, respectively) and biofilm (0.34%, 5.18%, and 0.98%, respectively). Overall, this study provides new insight into the high-efficiency treatment of landfill leachate at full-scale landfill sites.}, } @article {pmid33895669, year = {2021}, author = {Ali, A and Wu, Z and Li, M and Su, J}, title = {Carbon to nitrogen ratios influence the removal performance of calcium, fluoride, and nitrate by Acinetobacter H12 in a quartz sand-filled biofilm reactor.}, journal = {Bioresource technology}, volume = {333}, number = {}, pages = {125154}, doi = {10.1016/j.biortech.2021.125154}, pmid = {33895669}, issn = {1873-2976}, mesh = {*Acinetobacter/genetics ; Biofilms ; Bioreactors ; Calcium ; Carbon ; Denitrification ; Fluorides ; *Nitrates ; Nitrogen ; Quartz ; RNA, Ribosomal, 16S/genetics ; Sand ; }, abstract = {This study investigated the influence of different carbon to nitrogen (C/N) ratios on the bio-removal efficiency of aquatic pollutants like calcium (Ca[2+]), fluoride (F[-]), and nitrate (NO3-N) in a quartz sand-filled biofilm reactor (QSBR) to treat the low C/N wastewater using Acinetobacter sp. H12 at pH 6.50. The simultaneous bio-removal rate of Ca[2+], F[-], and NO3[-] reached 56.31%, 96.33, and 96.95 respectively. Nitrogen gas (N2) was produced with no evidence of N2O emission. Moreover, the morphological study of strain H12 and biological precipitates through SEM revealed that strain H12 provides the nucleation sites for microbially induced calcium precipitation to remove Ca[2+] and F[-]. Besides, XPS and XRD peak spectra implicated that Ca[2+] and F[-] were removed as CaF2 and Ca5(PO4)3F co-precipitates. The 16S rRNA sequencing analyses revealed that H12 belongs to Acinetobacter and has stronger MICP and denitrification potential as compared with other strains under low C/N conditions.}, } @article {pmid33894809, year = {2021}, author = {Ni, B and Wu, HS and Xin, YQ and Zhang, QW and Zhang, YQ}, title = {Reciprocal Regulation between Fur and Two RyhB Homologs in Yersinia pestis, and Roles of RyhBs in Biofilm Formation.}, journal = {Biomedical and environmental sciences : BES}, volume = {34}, number = {4}, pages = {299-308}, doi = {10.3967/bes2021.039}, pmid = {33894809}, issn = {2214-0190}, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial/*physiology ; Yersinia pestis/genetics/*physiology ; }, abstract = {OBJECTIVE: To investigate reciprocal regulation between Fur and two RyhB homologs in Yersinia pestis(Y. pestis), as well as the roles of RyhBs in biofilm formation.

METHODS: Regulatory relationships were assessed by a combination of colony morphology assay, primer extension, electrophoretic mobility shift assay and DNase I footprinting.

RESULTS: Fur bound to the promoter-proximal DNA regions of ryhB1 and ryhB2 to repress their transcription, while both RyhB1 and RyhB2 repressed the expression of Fur at the post-transcriptional level. In addition, both RyhB1 and RyhB2 positively regulated Y. pestis biofilm exopolysaccharide (EPS) production and the expression of hmsHFRS and hmsT.

CONCLUSION: Fur and the two RyhB homologs exert negative reciprocal regulation, and RyhB homologs have a positive regulatory effect on biofilm formation in Y. pestis.}, } @article {pmid33894074, year = {2021}, author = {Casagrande Pierantoni, D and Corte, L and Casadevall, A and Robert, V and Cardinali, G and Tascini, C}, title = {How does temperature trigger biofilm adhesion and growth in Candida albicans and two non-Candida albicans Candida species?.}, journal = {Mycoses}, volume = {64}, number = {11}, pages = {1412-1421}, pmid = {33894074}, issn = {1439-0507}, mesh = {*Biofilms/growth & development ; Candida/*physiology ; Candida albicans/*physiology ; Candidiasis/microbiology ; Cell Adhesion/physiology ; Cross Infection/microbiology ; *Temperature ; }, abstract = {BACKGROUND: Biofilm formation on biotic and abiotic surfaces is finely regulated by genetic factors but also by oxygen concentration, pH, temperature and other environmental factors, already extensively explored for bacterial biofilms. Much less is known about fungal biofilm, that is considered a virulence factor for Candida pathogenic species among the few fungal species able to grow and survive at high temperatures such as 37°C as well as those induced by fever. The resistance to high temperatures coupled with the ability to form biofilm are threatening factors of these fungal species that could severely impact at an epidemiological level.

OBJECTIVES: In this framework, we decided to study the thermal tolerance of biofilms formed by three medical relevant species such as Candida albicans and two non-Candida albicans Candida species.

METHODS: Thirty nosocomial strains were investigated for their ability to adhere and grow in proximity and over body temperature (from 31 to 43°C), mimicking different environmental conditions or severe febrile-like reactions.

RESULTS: Candida sessile cells reacted to different temperatures showing a strain-specific response. It was observed that the attachment and growth respond differently to the temperature and that mechanism of adhesion has different outputs at high temperature than the growth.

CONCLUSIONS: This strain-dependent response is probably instrumental to guarantee the best success to cells for the infection, attachment and growth to occur. These observations reinforce the concept of temperature as a major trigger in the evolution of these species especially in this period of increasing environmental temperatures and excessive domestic heating.}, } @article {pmid33893556, year = {2021}, author = {Hui, WL and Perrotti, V and Piattelli, A and Ostrikov, KK and Fang, Z and Quaranta, A}, title = {Cold atmospheric plasma coupled with air abrasion in liquid medium for the treatment of peri-implantitis model grown with a complex human biofilm: an in vitro study.}, journal = {Clinical oral investigations}, volume = {25}, number = {12}, pages = {6633-6642}, pmid = {33893556}, issn = {1436-3771}, mesh = {Air Abrasion, Dental ; Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis/therapy ; *Plasma Gases ; Surface Properties ; Titanium ; }, abstract = {OBJECTIVE: Treatment of implants with peri-implantitis is often unsuccessful due to residual microbial biofilm hindering re-osseointegration. The aim of this study was to treat biofilm-grown titanium (Ti) implants with different modalities involving air abrasion (AA) and cold atmospheric plasma (CAP) to compare the effectiveness in surface decontamination and the alteration/preservation of surface topography.

MATERIALS AND METHODS: Saliva collected from a peri-implantitis patient was used to in vitro develop human biofilm over 35 implants with moderately rough surface. The implants were then mounted onto standardized acrylic blocks simulating peri-implantitis defects and treated with AA (erythritol powder), CAP in a liquid medium, or a combination (COM) of both modalities. The remaining biofilm was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by scanning electron microscope (SEM). The data were statistically analyzed using Kruskal-Wallis followed by Tukey's multiple comparison test.

RESULTS: In the present peri-implantitis model, the human complex biofilm growth was successful as indicated by the statistical significance between the negative and positive controls. All the treatment groups resulted in a remarkable implant surface decontamination, with values very close to the negative control for AA and COM. Indeed, statistically significant differences in the comparison between the positive control vs. all the treatment groups were found. SEM analysis showed no post-treatment alterations on the implant surface in all the groups.

CONCLUSIONS: Decontamination with AA delivering erythritol with or without CAP in liquid medium demonstrated compelling efficacy in the removal of biofilm from implants. All the tested treatments did not cause qualitative alterations to the Ti surface features. No specific effects of the CAP were observed, although further studies are necessary to assess its potential as monotherapy with different settings or in combination with other decontamination procedures.

CLINICAL RELEVANCE: CAP is a promising option in the treatment of peri-implantitis because it has potential to improve the elimination of bacterial plaque from implant surfaces, in inaccessible pockets or during open-flap debridement, and should stimulate the process of the re-osseointegration of affected dental implants by not altering surface features and roughness.}, } @article {pmid33893112, year = {2021}, author = {Mayton, HM and Walker, SL and Berger, BW}, title = {Disrupting Irreversible Bacterial Adhesion and Biofilm Formation with an Engineered Enzyme.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {13}, pages = {e0026521}, pmid = {33893112}, issn = {1098-5336}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/drug effects/growth & development ; Escherichia coli/*drug effects/physiology/ultrastructure ; Food Handling/methods ; Glycoside Hydrolases/*pharmacology ; Hydrophobic and Hydrophilic Interactions ; Listeria monocytogenes/*drug effects/physiology ; Plant Leaves/microbiology ; Salmonella typhimurium/*drug effects/physiology ; Spinacia oleracea/microbiology ; }, abstract = {Biofilm formation is often attributed to postharvest bacterial persistence on fresh produce and food handling surfaces. In this study, a predicted glycosyl hydrolase enzyme was expressed, purified, and validated for the removal of microbial biofilms from biotic and abiotic surfaces under conditions used for chemical cleaning agents. Crystal violet biofilm staining assays revealed that 0.1 mg/ml of enzyme inhibited up to 41% of biofilm formation by Escherichia coli O157:H7, E. coli 25922, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes. Furthermore, the enzyme was effective at removing mature biofilms, providing a 35% improvement over rinsing with a saline solution alone. Additionally, a parallel-plate flow cell was used to directly observe and quantify the impact of enzyme rinses on E. coli O157:H7 cells adhering to spinach leaf surfaces. The presence of 1 mg/liter enzyme resulted in nearly 6-times-higher detachment rate coefficients than a deionized (DI) water rinse, while the total cells removed from the surface increased from 10% to 25% over the 30-min rinse time, reversing the initial phases of biofilm formation. Enzyme treatment of all 4 cell types resulted in significantly reduced cell surface hydrophobicity and collapse of negatively stained E. coli 25922 cells imaged by electron microscopy, suggesting potential polysaccharide surface modification of enzyme-treated bacteria. Collectively, these results point to the broad substrate specificity and robustness of the enzyme for different types of biofilm stages, solution conditions, and pathogen biofilm types and may be useful as a method for the removal or inhibition of bacterial biofilm formation. IMPORTANCE In this study, the ability of an engineered enzyme to reduce bacterial adhesion and biofilm formation of several foodborne pathogens was demonstrated, representing a promising option for enhancing or replacing chlorine and other chemical sanitizers in food processing applications. Specifically, significant reductions of biofilms of the pathogens Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes are observed, as are reductions in initial adhesion. Enzymes have the added benefits of being green, sustainable alternatives to chemical sanitizers, as well as having a minimal impact on food properties, in contrast to many alternative antimicrobial options such as bleach that aim to minimize food safety risks.}, } @article {pmid33892538, year = {2021}, author = {Shin, C and Alhammali, A and Bigler, L and Vohra, N and Peszynska, M}, title = {Coupled flow and biomass-nutrient growth at pore-scale with permeable biofilm, adaptive singularity and multiple species.}, journal = {Mathematical biosciences and engineering : MBE}, volume = {18}, number = {3}, pages = {2097-2149}, doi = {10.3934/mbe.2021108}, pmid = {33892538}, issn = {1551-0018}, mesh = {*Biofilms ; Biomass ; *Nutrients ; Permeability ; Porosity ; }, abstract = {In this paper we describe a coupled model for flow and microbial growth as well as nutrient utilization. These processes occur within and outside the biofilm phase formed by the microbes. The primary challenge is to address the volume constraint of maximum cell density but also to allow some microbial presence outside the contiguous biofilm phase. Our model derives from the continuum analogues of the mechanism of cell shoving introduced in discrete biomass models, and in particular from the models exploiting singular diffusivity as well as from models of variational inequality type which impose explicit constraints. We blend these approaches and propose a new idea to adapt the magnitude of the diffusivity automatically so as to ensure the volume constraint without affecting the reactions; this construction can be implemented in many variants without deteriorating the overall efficiency. The second challenge is to account for the flow and transport in the bulk fluid phase adjacent to the biofilm phase. We use the Brinkman flow model with a spatially variable permeability depending on biomass amount. The fluid flow allows some advection of the nutrient within the biofilm phase as well as for the flow even when the pores are close to being plugged up. Our entire model is monolithic and computationally robust even in complex pore-scale geometries, and extends to multiple species. We provide illustrations of our model and of related approaches. The results of the model can be easily post-processed to provide Darcy scale properties of the porous medium, e.g., one can predict how the permeability changes depending on the biomass growth in many realistic scenarios.}, } @article {pmid33892520, year = {2021}, author = {Elmassry, MM and Bisht, K and Colmer-Hamood, JA and Wakeman, CA and San Francisco, MJ and Hamood, AN}, title = {Malonate utilization by Pseudomonas aeruginosa affects quorum-sensing and virulence and leads to formation of mineralized biofilm-like structures.}, journal = {Molecular microbiology}, volume = {116}, number = {2}, pages = {516-537}, pmid = {33892520}, issn = {1365-2958}, support = {R15 GM128072/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Biomineralization/physiology ; Catalase/biosynthesis ; Decanoates ; Disaccharides/biosynthesis ; Drug Resistance, Bacterial/*physiology ; Glycerol/metabolism ; Malonates/*metabolism ; Norfloxacin/pharmacology ; Oligopeptides/biosynthesis ; Pseudomonas aeruginosa/drug effects/metabolism/*pathogenicity ; Pyocyanine/biosynthesis ; Quorum Sensing/*physiology ; Serine Endopeptidases/biosynthesis ; Virulence ; Virulence Factors/metabolism ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that uses malonate among its many carbon sources. We recently reported that, when grown in blood from trauma patients, P. aeruginosa expression of malonate utilization genes was upregulated. In this study, we explored the role of malonate utilization and its contribution to P. aeruginosa virulence. We grew P. aeruginosa strain PA14 in M9 minimal medium containing malonate (MM9) or glycerol (GM9) as a sole carbon source and assessed the effect of the growth on quorum sensing, virulence factors, and antibiotic resistance. Growth of PA14 in MM9, compared to GM9, reduced the production of elastases, rhamnolipids, and pyoverdine; enhanced the production of pyocyanin and catalase; and increased its sensitivity to norfloxacin. Growth in MM9 decreased extracellular levels of N-acylhomoserine lactone autoinducers, an effect likely associated with increased pH of the culture medium; but had little effect on extracellular levels of PQS. At 18 hr of growth in MM9, PA14 formed biofilm-like structures or aggregates that were associated with biomineralization, which was related to increased pH of the culture medium. These results suggest that malonate significantly impacts P. aeruginosa pathogenesis by influencing the quorum sensing systems, the production of virulence factors, biofilm formation, and antibiotic resistance.}, } @article {pmid33891391, year = {2021}, author = {Lin, Y and Wang, L and Xu, K and Huang, H and Ren, H}, title = {Algae Biofilm Reduces Microbe-Derived Dissolved Organic Nitrogen Discharges: Performance and Mechanisms.}, journal = {Environmental science & technology}, volume = {55}, number = {9}, pages = {6227-6238}, doi = {10.1021/acs.est.0c06915}, pmid = {33891391}, issn = {1520-5851}, mesh = {Biofilms ; Eutrophication ; *Nitrogen/analysis ; Sewage ; *Wastewater ; }, abstract = {Microbe-derived dissolved organic nitrogen (mDON) can readily induce harmful phytoplankton blooms, and thus, restricting its discharges is necessary. Recently, algae biofilm (AB) has attracted increasing interest for its advantages in nutrient recovery. However, its features in mDON control remain unexplored. Herein, AB's mDON formation and utilization performance, molecular characteristics, and metabolic traits have been investigated, with activated sludge (AS) as the benchmark for comparisons. Comparatively, AB reduced mDON formation by 83% when fed with DON-free wastewater. When fed with AS's effluent, it consumed at least 72% of the exogenous mDON and notably reduced the amount of protein/amino sugar-like compounds. Irrespective of the influent, AB ultimately produced more various unsaturated hydrocarbon and lignin analogues. Redundancy and network analysis highlighted the algal-bacterial synergistic effects exemplified by cross-feeding in reducing mDON concentrations and shaping mDON pools. Moreover, metagenomics-based metabolic reconstruction revealed that cyanobacteria Limnothrix and Kamptonema spp. facilitated mDON uptake, ammonification, and recycling, which supplied the extensive nitrogen assimilatory demand for amino acids, vitamins, and cofactors biosynthesis, and therefore promoted mDON scavenging. Our findings demonstrate that regardless of the secondary or tertiary process, cyanobacteria-dominated AB is promising to minimize bioavailable mDON discharges, which has implications for future eutrophication control.}, } @article {pmid33891172, year = {2021}, author = {Fan, M and Yang, J and Xu, HHK and Weir, MD and Tao, S and Yu, Z and Liu, Y and Li, M and Zhou, X and Liang, K and Li, J}, title = {Remineralization effectiveness of adhesive containing amorphous calcium phosphate nanoparticles on artificial initial enamel caries in a biofilm-challenged environment.}, journal = {Clinical oral investigations}, volume = {25}, number = {9}, pages = {5375-5390}, pmid = {33891172}, issn = {1436-3771}, support = {81800965//National Natural Science Foundation of China (CN)/ ; 81670977//National Natural Science Foundation of China/ ; 51903169//National Natural Science Foundation of China/ ; 2017SZ0030//Sichuan Province Science and Technology Support Program/ ; Research Fund of Chinese Stomatological Association//Research Fund of Chinese Stomatological Association/ ; 2018M643507//China Postdoctoral Foundation/ ; 2019037//Miaozi Project in Science and Technology Innovation Program of Sichuan Province/ ; 0040304153013//Postdoctoral Cross Funding of Sichuan University/ ; }, mesh = {Anti-Bacterial Agents ; Biofilms ; Calcium Phosphates ; *Dental Caries/drug therapy ; Dental Caries Susceptibility ; Dental Cements ; Humans ; Methacrylates ; *Nanoparticles ; Tooth Remineralization ; }, abstract = {OBJECTIVES: Dental caries is closely associated with acid-producing bacteria, and Streptococcus mutans is one of the primary etiological agents. Bacterial accumulation and dental demineralization lead to destruction of bonding interface, thus limiting the longevity of composite. The present study investigated remineralization effectiveness of adhesive containing nanoparticles of amorphous calcium phosphate (NACP) in a stimulated oral biofilm environment.

METHODS: The enamel blocks were immersed in demineralization solution for 72 h to imitate artificial initial carious lesion and then subjected to a Streptococcus mutans biofilm for 24 h. All the samples then underwent 4-h demineralization in brain heart infusion broth with sucrose (BHIS) and 20-h remineralization in artificial saliva (AS) for 7 days. The daily pH of BHIS after 4-h incubation, lactic acid production, colony-forming unit (CFU) count, and content of calcium (Ca) and phosphate (P) in biofilm were evaluated. Meanwhile, the remineralization effectiveness of enamel was analyzed by X-ray diffraction (XRD), surface microhardness testing, transverse microradiography (TMR) and scanning electron microscopy (SEM).

RESULTS: The NACP adhesive released abundant Ca and P, achieved acid neutralization, reduced lactic acid production, and lowered CFU count (P < 0.05). Enamel treated with NACP adhesive demonstrated the best remineralization effectiveness with remineralization value of 52.29 ± 4.79% according to TMR. Better microhardness recovery of cross sections and ample mineral deposits were also observed in NACP group.

CONCLUSIONS: The NACP adhesive exhibited good performance in remineralizing initial enamel lesion with cariogenic biofilm.

SIGNIFICANCE: The NACP adhesive is promising to be applied for the protection of bonding interface, prevention of secondary caries, and longevity prolonging of the restoration.}, } @article {pmid33890937, year = {2021}, author = {Laheij, AMGA and de Soet, JJ and Crielaard, W and Zemouri, C and Volgenant, CMC}, title = {[Cross contamination: spatters, aerosols, and biofilm in dental practices].}, journal = {Nederlands tijdschrift voor tandheelkunde}, volume = {128}, number = {4}, pages = {221-227}, doi = {10.5177/ntvt.2021.04.20100}, pmid = {33890937}, issn = {0028-2200}, mesh = {Aerosols ; *Biofilms ; Humans ; }, abstract = {During treatment in dental practices, drops of different sizes are produced (spats and aerosols). Microorganisms in these drops are of human origin or originate from the water in the dental unit. Therefore, these drops can contribute to cross contamination in dental practices. Large drops settle quickly, while smaller drops can remain suspended in the air for a longer period of time. The highest level of contamination is found in the immediate vicinity of the source (the patient's mouth). Further away from the source and after stopping drop producing activities, the level of contamination in the air is comparable to control circumstances. Studies into the spread of viruses via this route in the dental practice have not yet been conducted. The risk of catching an infectious disease in the dental practice seems limited, but can be high in the case of a virulent microorganism, when the circumstances for spread of the virus are favorable, or if the recipient is immunocompromised.}, } @article {pmid33890735, year = {2021}, author = {Weigelt, MA and Lev-Tov, H}, title = {Intralesional anti-biofilm therapy for tunnels in patients with hidradenitis suppurativa.}, journal = {Italian journal of dermatology and venereology}, volume = {156}, number = {5}, pages = {618-619}, doi = {10.23736/S2784-8671.21.06899-1}, pmid = {33890735}, issn = {2784-8450}, mesh = {Biofilms ; *Hidradenitis Suppurativa/drug therapy ; Humans ; }, } @article {pmid33890354, year = {2021}, author = {Nguyen, JM and Moore, RE and Spicer, SK and Gaddy, JA and Townsend, SD}, title = {Synthetic Phosphoethanolamine Cellobiose Promotes Escherichia coli Biofilm Formation and Congo Red Binding.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {22}, number = {15}, pages = {2540-2545}, pmid = {33890354}, issn = {1439-7633}, support = {R01 HD090061/HD/NICHD NIH HHS/United States ; R01HD090061/NH/NIH HHS/United States ; R35GM133602/NH/NIH HHS/United States ; R35 GM133602/GM/NIGMS NIH HHS/United States ; //College of Arts & Science at Vanderbilt University/ ; 1847804//National Science Foundation/ ; }, mesh = {*Escherichia coli ; }, abstract = {Urinary tract infections (UTIs) are caused by bacteria growing in complex, multicellular enclosed aggregates known as biofilms. Recently, a zwitterionic cellulose derivative produced in Escherichia coli (E. coli) was determined to play an important role in the formation and assembly of biofilms. In order to produce a minimal, yet structurally defined tool compound to probe the biology of the naturally occurring polymer, we have synthesized a zwitterionic phosphoethanolamine cellobiose (pEtN cellobiose) and evaluated its biofilm activity in the Gram-negative bacterium E. coli, a pathogen implicated in the pathogenesis of UTIs. The impact of synthetic pEtN cellobiose on biofilm formation was examined via colorimetric assays which revealed an increase in cellular adhesion to an abiotic substrate compared to untreated samples. Additionally, Congo red binding assays indicate that culturing E. coli in the presence of pEtN cellobiose enhances Congo Red binding to bacterial cells. These results reveal new opportunities to study the impact glycopolymers have on cellular adhesion in Gram-negative pathogens.}, } @article {pmid33889308, year = {2021}, author = {Cai, JN and Choi, HM and Jeon, JG}, title = {Relationship between sucrose concentration and bacteria proportion in a multispecies biofilm: Short title: Sucrose challenges to a multispecies biofilm.}, journal = {Journal of oral microbiology}, volume = {13}, number = {1}, pages = {1910443}, pmid = {33889308}, issn = {2000-2297}, abstract = {Objective: The aim of this study was to evaluate the relationship between sucrose concentration and bacteria proportion in a multispecies biofilm model. Methods: Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), and Actinomyces naeslundii (A. naeslundii) were chose to form a multispecies biofilm. Different concentration (0-40%) of sucrose was introduced to the multispecies biofilm 3 times per day (30 min per time). And then the bacteria proportion and acid production of the biofilms were analyzed. Results: Increasing sucrose level increased CFU count of S. mutans up to a certain concentration (5% sucrose), after which the number of S. mutans slightly decreased, but the CFU counts of S. oralis and A. naeslundii continually decreased with sucrose concentration increase, especially, from 5% sucrose, the reduction was significant, and S. mutans became the dominant species in the biofilms. Furthermore, the acid production ability of the multispecies biofilm gradually increased and slightly decreased with sucrose concentration increased, and the turning concentration was 5%. Conclusion: Our findings suggest that increasing sucrose level could increase the competitiveness of S. mutans in the multispecies biofilm, which may shift the biofilm to a more cariogenic one, and 5% sucrose formed a most cariogenic biofilm in this study.}, } @article {pmid33888996, year = {2021}, author = {Chan, AKY and Tsang, YC and Chu, CH and Tsang, CSP}, title = {Aspirin as an Antifungal-Lock Agent in Inhibition of Candidal Biofilm Formation in Surgical Catheters.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {1427-1433}, pmid = {33888996}, issn = {1178-6973}, abstract = {BACKGROUND: The antibiotic lock technique (ALT) has been recommended for the prevention and treatment of catheter-related candidaemia. Biofilms of Candida species are resistant to some of the antifungal agents currently used. Aspirin has been shown to have anti-fungal effect but its effect on candidal biofilm is poorly understood.

PURPOSE: The aim of the current study was to evaluate the anti-biofilm effect of aspirin on Candida biofilms including C. albicans, C. glabrata, C. krusei and C. tropicalis formed on surgical catheters and the concentration and time required to eradicate the biofilms.

METHODS: Biofilms of Candida species were grown on silicone catheters and incubated in aspirin at different concentrations for 2, 4 and 24 hours. The biofilms remaining were then determined quantitatively by colony-forming unit (CFU) counts and XTT assays.

RESULTS: The results demonstrated that among the tested Candida species, C. albicans was the most sensitive species towards aspirin. Aspirin at a concentration of 40 mg/mL in 4 hours was effective in eradicating the biofilm. For all the other tested species, they were eradicated by aspirin at a concentration of 40 mg/mL in 24 hours.

CONCLUSION: Our results showed that aspirin may be used as an anti-fungal agent in lock therapy in the treatment of catheter-related candidaemia.}, } @article {pmid33887078, year = {2021}, author = {Catão C P, E and Pollet, T and Garnier, C and Barry-Martinet, R and Rehel, K and Linossier, I and Tunin-Ley, A and Turquet, J and Briand, JF}, title = {Temperate and tropical coastal waters share relatively similar microbial biofilm communities while free-living or particle-attached communities are distinct.}, journal = {Molecular ecology}, volume = {30}, number = {12}, pages = {2891-2904}, doi = {10.1111/mec.15929}, pmid = {33887078}, issn = {1365-294X}, mesh = {*Biofilms ; Indian Ocean ; Mediterranean Sea ; *Microbiota/genetics ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Free-living (FL) marine microbial communities differ from those attached to particles (PA). Likewise, biofilms (B) colonizing artificial surfaces, including plastics or ship hulls, hardly resemble their planktonic surroundings. However, few studies have examined the effect of the environment on these lifestyles and on the source of organisms colonizing marine surfaces. Using 16S rRNA gene metabarcoding, we identified specificities of marine prokaryotic community lifestyles (FL, PA or B) sampled in three coastal polluted locations with dissimilar environmental conditions: the North-Western Mediterranean Sea and the Atlantic and Indian Oceans. Biofilms developed over polyvinyl chloride (PVC) were found to be significantly different from FL or PA collected during the immersions. Alpha-diversity increased from FL to PA and to B, illustrating the integrative aspect of the latter, with little proportion of operational taxonomic units shared with the first two. Beta-diversity clustered first the lifestyles and then the sites. FL and PA were more affected by water quality, especially by trace metal contamination, whereas B were as sensitive to trace metals as to nutrients. Although biofilms should be supplied by the planktonic (ultra) rare biosphere, source tracking could only detect small contributions of FL or PA taxa to B communities.}, } @article {pmid33886943, year = {2021}, author = {Moraes, GS and Albach, T and Ramos, IE and Kopacheski, MG and Cachoeira, VS and Sugio, CYC and Galvão Arrais, CA and Neppelenbroek, KH and Urban, VM}, title = {A novel acrylic resin palatal device contaminated with Candida albicans biofilm for denture stomatitis induction in Wistar rats.}, journal = {Journal of applied oral science : revista FOB}, volume = {29}, number = {}, pages = {e20200865}, pmid = {33886943}, issn = {1678-7765}, mesh = {Acrylic Resins ; Animals ; Biofilms ; *Candida albicans ; Denture Bases ; Palate ; Rats ; Rats, Wistar ; *Stomatitis, Denture ; }, abstract = {UNLABELLED: Denture stomatitis is the most frequent oral lesion in removable prosthesis wearers, with high recurrence rates and a complex treatment.

OBJECTIVE: This study describes a protocol to obtain and to contaminate a palatal device with Candida albicans biofilm that could be used for an animal model of denture stomatitis.

METHODOLOGY: Acrylic resin devices (N=41) were obtained from impressions of the palates of Wistar rats with individual trays and polyether. The efficacy of microwave irradiation (MW), ultraviolet light (UV), or ultrasonic bath (US) was assessed by colony viability and spectrophotometric analyses (n=5) in order to select the most appropriate method for sterilizing the devices. Then, different devices (n=5) were contaminated with C. albicans and evaluated by CFU/mL determination, scanning electron microscopy, and laser confocal microscopy. Device stabilization was assessed with either autopolymerizing acrylic resins or a self-adhesive resin cement (n=2). The spectrophotometric data were analyzed by one-way ANOVA followed by the Tukey's HSD post-hoc test (α=0.05).

RESULTS: MW was the only method capable of sterilizing the devices, and the contamination protocol developed a mature and viable C. albicans biofilm (~1.2 x 106 CFU/mL). The self-adhesive resin cement was the best stabilization material.

CONCLUSIONS: This acrylic resin palatal device was designed to be similar to the clinical situation of contaminated prostheses, with easy manufacturing and handling, effective stabilization, and satisfactory contamination. Thus, the acrylic device can be a valuable tool in the development of denture stomatitis in rats.}, } @article {pmid33879237, year = {2021}, author = {Bostanghadiri, N and Ardebili, A and Ghalavand, Z and Teymouri, S and Mirzarazi, M and Goudarzi, M and Ghasemi, E and Hashemi, A}, title = {Antibiotic resistance, biofilm formation, and biofilm-associated genes among Stenotrophomonas maltophilia clinical isolates.}, journal = {BMC research notes}, volume = {14}, number = {1}, pages = {151}, pmid = {33879237}, issn = {1756-0500}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial ; *Gram-Negative Bacterial Infections/drug therapy ; Humans ; Microbial Sensitivity Tests ; *Stenotrophomonas maltophilia/genetics ; }, abstract = {OBJECTIVE: The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques.

RESULTS: All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100%, 97.65%, and 95.29%, respectively. The results of crystal violet staining assay showed that all isolates (100%) form biofilm. Moreover, 24 (28.23%), 32 (37.65%), and 29 (34.12%) of isolates were categorized as weak, moderate, and strong biofilm producers, respectively. Biofilm genes including rpfF, spgM and rmlA had an overall prevalence of 89.41% (76/85), 100% (85/85) and 84.71% (72/85), respectively. Rational prescribing of antibiotics and implementation of infection control protocols are necessary to prevent further infection and development of antimicrobial resistance. Combination strategies based on the appropriate antibiotics along with anti-biofilm agents can also be selected to eliminate biofilm-associated infections.}, } @article {pmid33878395, year = {2021}, author = {Sasani, E and Khodavaisy, S and Rezaie, S and Salehi, M and Yadegari, MH}, title = {The relationship between biofilm formation and mortality in patients with Candida tropicalis candidemia.}, journal = {Microbial pathogenesis}, volume = {155}, number = {}, pages = {104889}, doi = {10.1016/j.micpath.2021.104889}, pmid = {33878395}, issn = {1096-1208}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida tropicalis/genetics ; *Candidemia ; Drug Resistance, Fungal ; Fluconazole/pharmacology ; Humans ; Iran ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Biofilm formation by Candida species is an influential virulence factor in candidemia pathogenesis. We investigated the relationship between biofilm formation of Candida tropicalis isolates with the clinical characteristics and mortality outcomes in patients with candidemia.

MATERIALS AND METHODS: Thirty-nine C. tropicalis isolates were recovered from patients with candidemia admitted to two university hospitals in Tehran, Iran. Biofilm mass and metabolic activity of C. tropicalis biofilms were assessed in vitro with two colorimetric methods. The sessile minimum inhibitory concentrations (SMICs) were evaluated in vitro by treating preformed biofilms with diluted concentrations of azoles according to CLSI-M27 A3/S4 protocol, followed by metabolic activity quantification. The expressions of ERG11, UPC2, MDR1, and CDR1 genes were also evaluated.

RESULTS: All C. tropicalis isolates produced biofilm. Respectively, higher <7-day and ≥7-day mortality rates were found among cases with high metabolic activity (46.7% vs. 13%, P = 0.03) and high biofilm mass (31.8% vs. 0, P = 0.029). Sessile cells had high resistance to fluconazole, voriconazole, and itraconazole. The azole minimum inhibitory concentrations (MICs) of C. tropicalis sessile were significantly greater than the planktonic minimum inhibitory concentrations (PMICs). In fluconazole-treated biofilms, the expression of ERG11 and UPC2 genes was increased.

CONCLUSION: Our findings highlight the importance of C. tropicalis biofilm formation as an important factor in candidemia pathogenesis and the clinical outcome of patients with candidemia.}, } @article {pmid33878355, year = {2021}, author = {Hasan, I and Rahman, SN and Islam, MM and Ghosh, SK and Mamun, MR and Uddin, MB and Shaha, RK and Kabir, SR}, title = {A N-acetyl-D-galactosamine-binding lectin from Amaranthus gangeticus seeds inhibits biofilm formation and Ehrlich ascites carcinoma cell growth in vivo in mice.}, journal = {International journal of biological macromolecules}, volume = {181}, number = {}, pages = {928-936}, doi = {10.1016/j.ijbiomac.2021.04.052}, pmid = {33878355}, issn = {1879-0003}, mesh = {Acetylgalactosamine/antagonists & inhibitors/chemistry ; Amaranthus/*chemistry ; Animals ; Apoptosis ; Ascites/drug therapy/genetics/pathology ; Biofilms/*drug effects/growth & development ; Carcinoma, Ehrlich Tumor/*drug therapy/genetics/pathology ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Lectins/chemistry/*pharmacology ; Mice ; NF-kappa B/genetics ; Plant Lectins/chemistry ; Seeds/chemistry ; }, abstract = {AGL, a 15-kDa lectin from Amaranthus gangeticus seeds was isolated using ion-exchange and gel filtration chromatography. AGL contained 8.55% of neutral sugar and became specifically inhibited by N-acetyl-D-galactosamine. Hemagglutination activity of the lectin was maximum over the pH range of 4.0-6.0 and temperatures of 30-60 °C though it lost the activity when treated with urea and EDTA. With an LC50 value of 250 μg/ml, AGL showed mild toxicity against Artemia nauplii. It inhibited the growth of pathogenic bacteria like Shigella boydii, Shigella dysenteriae and Staphylococcus aureus when treated for 8 and 16 h, respectively, but lost the antibacterial activity during a 24 h treatment. AGL could not inhibit the growth of Escherichia coli and mitogenic growth (7.0-9.0%) was observed instead. AGL inhibited 37.14%, 65.71% and 82.85% of biofilm formation of Escherichia coli at the concentrations of 250, 500 and 1000 μg/ml, respectively. Marked inhibition of the proliferation of Ehrlich ascites carcinoma cells was determined when treated with various doses of AGL. AGL inhibited 65.89% and 81.25% of the in vivo growth of EAC cells in mice at the doses of 2.0 and 4.0 mg/kg/day, respectively. Significant alteration of the expression of apoptosis related genes Fas, NF-kB and MAPK were observed.}, } @article {pmid33876689, year = {2021}, author = {Wolcott, R}, title = {Biofilm and catheter-related bloodstream infections.}, journal = {British journal of nursing (Mark Allen Publishing)}, volume = {30}, number = {8}, pages = {S4-S9}, doi = {10.12968/bjon.2021.30.8.S4}, pmid = {33876689}, issn = {0966-0461}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Bacteremia/etiology/prevention & control ; Biofilms ; *Catheter-Related Infections/drug therapy/prevention & control ; Catheterization ; Catheters ; Humans ; *Sepsis/prevention & control ; }, abstract = {Careful attention to detail and adherence to procedure guidelines when inserting and managing intravascular catheters has decreased the incidence of catheter-related bloodstream infections (CRBSIs). In order to limit these, health professionals must understand the underlying microbiology. Biofilms can explain the clinical findings most often seen with CRBSIs, yet they are poorly understood within medicine. Bacteria growing on solid surfaces such as a catheter are predominantly in biofilm phenotype, with a group of genes active that allow the bacteria to be tolerant to antiseptics and antibiotics by producing a self-secreted protective matrix. It is unclear whether it is planktonic seeding or small fragments of biofilm breaking off into the bloodstream that eventually results in the acute infection. The literature identifies four routes for microbes to adhere to a catheter and start biofilm formation: catheter contact, catheter insertion, catheter management and non-catheter-related sources. Routine clinical culture methods are inadequate to fully identify microbes producing catheter biofilm and/or bloodstream infection, therefore DNA methods may be required to diagnose CRBSIs. Treatment is removal and reinsertion of the catheter in a different site when possible. However, antibiofilm strategies can be employed to try to salvage the catheter. The use of high-dose antiseptics or antibiotics for long durations inside the catheter and hub (antibiotic/antiseptic lock) can suppress biofilm enough to reduce the seeding of the blood below a level where the patient's immune system can prevent bloodstream infection.}, } @article {pmid33875220, year = {2021}, author = {Zhang, Y and Huang, HH and Duc, HM and Masuda, Y and Honjoh, KI and Miyamoto, T}, title = {Endolysin LysSTG2: Characterization and application to control Salmonella Typhimurium biofilm alone and in combination with slightly acidic hypochlorous water.}, journal = {Food microbiology}, volume = {98}, number = {}, pages = {103791}, doi = {10.1016/j.fm.2021.103791}, pmid = {33875220}, issn = {1095-9998}, mesh = {Bacteriophages/*enzymology/genetics ; *Biofilms/drug effects ; Chlorine/*pharmacology ; Endopeptidases/genetics/*metabolism ; Hypochlorous Acid/*pharmacology ; Salmonella typhimurium/*drug effects/genetics/physiology/*virology ; Viral Proteins/genetics/*metabolism ; Water/chemistry ; }, abstract = {The gene encoding LysSTG2, an endolysin from Salmonella-lytic bacteriophage STG2, was cloned, overexpressed, and characterized. LysSTG2 consists of a single domain belonging to the Peptidase_M15 superfamily. LysSTG2 showed strong lytic activity against chloroform-treated S. Typhimurium cells after incubation at 4-50 °C for 30 min, at pH ranging from 7.0 to 11.0, and in the presence of NaCl from 0 to 300 mmol/L. It also showed lytic activity against all the 14 tested Gram-negative strains treated with chloroform, including Salmonella, E. coli, and Pseudomonas aeruginosa, but not against the Gram-positive bacteria tested. In addition, LysSTG2 (100 μg/mL) reduced the viability of S. Typhimurium NBRC 12529 planktonic cells by 1.2 log and that of the biofilm cells after 1-h treatment. Sequential treatment of slightly acidic hypochlorous water (SAHW) containing 40 mg/L available chlorine and LysSTG2 (100 μg/mL) was effective on S. Typhimurium NBRC 12529 biofilm cells, removing more than 99% of biofilm cells. These results demonstrate that LysSTG2 alone can effectively kill S. Typhimurium cells after permeabilization treatment and successfully control S. Typhimurium in biofilms in combination with SAHW, suggesting that the combined use of LysSTG2 and SAHW might be a novel and promising method for combating S. Typhimurium in food industries.}, } @article {pmid33875213, year = {2021}, author = {Xu, Z and Liu, Z and Soteyome, T and Hua, J and Zhang, L and Yuan, L and Ye, Y and Cai, Z and Yang, L and Chen, L and Harro, JM and Kjellerup, BV and Liu, J and Li, Y}, title = {Impact of pmrA on Cronobacter sakazakii planktonic and biofilm cells: A comprehensive transcriptomic study.}, journal = {Food microbiology}, volume = {98}, number = {}, pages = {103785}, doi = {10.1016/j.fm.2021.103785}, pmid = {33875213}, issn = {1095-9998}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cronobacter sakazakii/*genetics/growth & development/physiology ; Gene Expression Regulation, Bacterial ; Plankton/*genetics/growth & development/physiology ; Transcription, Genetic ; *Transcriptome ; Virulence Factors/genetics/metabolism ; }, abstract = {Cronobacter sakazakii is an emerging opportunistic foodborne pathogen causing rare but severe infections in neonates. Furthermore, the formation of biofilm allows C. sakazakii to persist in different environments. We have demonstrated that the mutator phenotype ascribed to deficiency of the pmrA gene results in more biomass in the first 24 h but less during the post maturation stage (7-14 d) compared with BAA 894. The present study aimed to investigate the regulatory mechanism modulating biofilm formation due to pmrA mutation. The transcriptomic analyses of BAA 894 and s-3 were performed by RNA-sequencing on planktonic and biofilm cells collected at different time points. According to the results, when comparing biofilm to planktonic cells, expression of genes encoding outer membrane proteins, lysozyme, etc. were up-regulated, with LysR family transcriptional regulators, periplasmic proteins, etc. down-regulated. During biofilm formation, cellulose synthase operon genes, flagella-related genes, etc. played essential roles in different stages. Remarkably, pmrA varies the expression of a number of genes related to motility, biofilm formation, and antimicrobial resistance, including srfB, virK, mviM encoding virulence factor, flgF, fliN, etc. encoding flagellar assembly, and marA, ramA, etc. encoding AraC family transcriptional regulators in C. sakazakii. This study provides valuable insights into transcriptional regulation of C. sakazakii pmrA mutant during biofilm formation.}, } @article {pmid33874869, year = {2022}, author = {Ali, FA}, title = {Association Between Biofilm Formation Gene Bla exoU and Metallo and Extend Spectrum Beta-lactamase Production of Multidrug Resistance Pseudomonas aeruginosa in Clinical Samples.}, journal = {Combinatorial chemistry & high throughput screening}, volume = {25}, number = {7}, pages = {1207-1218}, doi = {10.2174/1386207324666210419112210}, pmid = {33874869}, issn = {1875-5402}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Burns ; Drug Resistance, Multiple ; Humans ; Microbial Sensitivity Tests ; *Pseudomonas Infections/drug therapy/epidemiology ; Pseudomonas aeruginosa/genetics ; beta-Lactamases/genetics/pharmacology ; }, abstract = {BACKGROUND: The presence of biofilm formation exoU gene is a significant challenge to infection control management in hospitals and exposure by Pseudomonas aeruginosa may lead to further spread and development of antimicrobial resistance.

METHODS: Out of 227 samples, 40 clinical isolates of P. aeruginosa were collected from patients attending public hospitals (Rizgary, Teaching hospital, Laboratory center, Raparin, Nanakaly hospitals) in Erbil city, Iraq over a period during June 2018 to March 2019 and were fully characterized by standard bacteriological procedures and antimicrobial susceptibility test and ESBL has been carried out by Vitek 2 compact system and by Vitek 2 compact system. The identification has been verified by all isolates as P. aeruginosa by using 16S rDNA with product size (956pb).

RESULTS: A high rate of resistance was seen against Penicillin, Lincomycin, Piperacillin and Chloramphenicol and Rifampicin (100 %), whereas Imipenem (5%) was found to be the most effective antimicrobial drug. Of all P. aeruginosa isolates, 30 (75% %) were identified as MDR, approximately 9 (22.5%) isolates were resistant to 9 drugs in burn samples. Quantitative biofilm determination using the Congo red method revealed that 28 isolates (70%) produced biofilm, biofilm production was significantly higher among MDR P. aeruginosa isolates while coproduction of Extended Spectrum β-lactamase (ESBL) together with Metallo β-lactamase (MBL) ESBLs MBLs was recorded in 52.5% of the isolates. Altogether 40 isolates were processed for the analysis by PCR assays and showed that 26 (70%) of P. aeruginosa isolates harboured the exoU encoding gene with product size (204) pb was more commonly seen in isolates obtained from burn isolates. In addition, exo U gene was significantly associated with the higher MDR (80%), 8 isolates (76.9%) had exoU gene with ESBL and (65%) had MBL and the same for MDR (80.8%) in samples for burning.

CONCLUSION: Our results showed surveillance of P. aeruginosa resistance against antimicrobial and ESBL and MBL is fundamental to monitor trends in susceptibility patterns and appropriately guide clinicians in choosing empirical or directed therapy.}, } @article {pmid33872997, year = {2021}, author = {Huang, W and Zhou, J and He, X and He, L and Lin, Z and Shi, S and Zhou, J}, title = {Simultaneous nitrogen and phosphorus removal from simulated digested piggery wastewater in a single-stage biofilm process coupling anammox and intracellular carbon metabolism.}, journal = {Bioresource technology}, volume = {333}, number = {}, pages = {125152}, doi = {10.1016/j.biortech.2021.125152}, pmid = {33872997}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Carbon ; Denitrification ; Nitrification ; *Nitrogen ; Phosphorus ; RNA, Ribosomal, 16S/genetics ; Sewage ; *Wastewater ; }, abstract = {A Single-stage biofilm process coupling Anammox and Intracellular Carbon metabolism (SAIC) was constructed for treating simulated digested piggery wastewater with low carbon/nitrogen ratio (C/N) in this study. TN removal in SAIC system increased by more than 12.77% compared to the reference, and the maximum total phosphorus (TP) removal efficiency reached to 83.70% (C/N = 1.5). Denitrification driven by intracellular carbon, mainly poly-β-hydroxybutyrate (PHB, 78.57%), contributed 32.60% of TN elimination at most, and at least 67.40% should be attributed to anammox. Phosphorus was thought to be mainly removed through biological route, while chemical precipitation also explained around 10% of removed TP. Furthermore, commensalism of glycogen accumulating organisms (GAOs), phosphate accumulating organisms (PAOs), nitrifiers and anammox bacteria was revealed by combining 16S rRNA amplicon sequencing and metagenomics. As a result, multiple metabolic pathways including anammox, (partial) nitrification, endogenous (partial) denitrification and biological P-removal played synergistic effect in SAIC system.}, } @article {pmid33870731, year = {2021}, author = {Queiroz, HA and da Silva, CR and de Andrade Neto, JB and do Av Sá, LG and do Nascimento, FB and Moreno, LS and Barroso, FD and da Silva, LJ and Cândido, TM and de Oliveira, LC and de Mesquita, JR and de Moraes, MO and Cavalcanti, BC and Nobre Júnior, HV}, title = {Synergistic activity of diclofenac sodium with oxacillin against planktonic cells and biofilm of methicillin-resistant Staphylococcus aureus strains.}, journal = {Future microbiology}, volume = {16}, number = {}, pages = {375-387}, doi = {10.2217/fmb-2020-0095}, pmid = {33870731}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects ; DNA Damage/drug effects ; Diclofenac/*pharmacology ; Drug Synergism ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Oxacillin/*pharmacology ; }, abstract = {Aim: To evaluate the activity of diclofenac sodium and synergism with oxacillin against clinical strains of SARM in plactonic cells, antibiofilm and biofilm. Materials & methods: Synergism activity was assessed using the fractional inhibitory concentration index and its possible mechanism of action by flow cytometry. Results: The synergistic activity of diclofenac sodium with oxacillin was observed against plactonic cells, antibiofilm and in biofilm formed from clinical methicillin-resistant Staphylococcus aureus strains. Conclusion: This combination caused damage to the integrity of the membrane and ruptures in the DNA of the cells, leading to apoptosis.}, } @article {pmid33869236, year = {2021}, author = {Kim, SG and Giri, SS and Yun, S and Kim, SW and Han, SJ and Kwon, J and Oh, WT and Lee, SB and Park, YH and Park, SC}, title = {Two Novel Bacteriophages Control Multidrug- and Methicillin-Resistant Staphylococcus pseudintermedius Biofilm.}, journal = {Frontiers in medicine}, volume = {8}, number = {}, pages = {524059}, pmid = {33869236}, issn = {2296-858X}, abstract = {As a primary bacterial pathogen in companion animals, Staphylococcus pseudintermedius has zoonotic potential. This pathogen exhibits multidrug resistance, including resistance to methicillin, and biofilm-forming ability, making it hard to eradicate with antimicrobial agents. One potential alternative is bacteriophage therapy. In this study, we first characterized the antimicrobial resistance profile of S. pseudintermedius from canine samples and isolated two novel bacteriophages, pSp-J and pSp-S, from canine pet parks in South Korea to potentially control S. pseudintermedius. The biological characteristics of phages were assessed, and the phages could infect most of the methicillin-resistant S. pseudintermedius strains. We found that these phages were stable under the typical environment of the body (~37°C, pH 7). We also assessed bacterial lysis kinetics using the two phages and their cocktail, and found that the phages could prevent biofilm formation at low doses and could degrade biofilm at high doses. Taken together, this study demonstrates that bacteriophages pSp-J and pSp-S isolated in this study can be used to potentially treat methicillin-resistant S. pseudintermedius.}, } @article {pmid33869087, year = {2021}, author = {Saeki, EK and Yamada, AY and de Araujo, LA and Anversa, L and Garcia, DO and de Souza, RLB and Martins, HM and Kobayashi, RKT and Nakazato, G}, title = {Subinhibitory Concentrations of Biogenic Silver Nanoparticles Affect Motility and Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {656984}, pmid = {33869087}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Fusarium ; Humans ; *Metal Nanoparticles ; *Pseudomonas aeruginosa ; Quorum Sensing ; Silver/pharmacology ; }, abstract = {Biogenic silver nanoparticles (bio-AgNPs) are increasingly recognized as an antibiofilm and antivirulence strategy against P. aeruginosa, a bacterium that causes chronic infections in immunocompromised and cystic fibrosis patients. This study aimed to investigate the effects of subinhibitory concentrations of bio-AgNPs on motility and biofilm formation in P. aeruginosa. Bio-AgNPs were synthesized via reduction of ionic silver catalyzed by cell-free culture filtrate from Fusarium oxysporum. A total of 17 P. aeruginosa isolates and strains were evaluated for swarming, swimming, and twitching motility in the presence and absence (control) of bio-AgNPs, including 10 clinical isolates from patients with and without cystic fibrosis, 5 environmental isolates obtained from the public water supply system, and 2 reference strains (PAO1 and PA14). Isolates were identified by biochemical and molecular methods. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method. Swarming, swimming, and twitching motility assays were performed in Petri dishes. Biofilm formation capacity was assessed quantitatively by the crystal violet method. MIC values ranged from 15.62 to 62.50 µM. The results showed that subinhibitory concentrations of bio-AgNPs (½ MIC, 7.81-31.25 µM) significantly increased (p < 0.05) swarming, swimming, and twitching motility in 40.0, 40.0, and 46.7% of isolates, respectively. Subinhibitory bio-AgNP treatment enhanced (p < 0.05) biofilm formation capacity in PA14 and a cystic fibrosis isolate (P11). It is concluded that subinhibitory concentrations of bio-AgNPs increased biofilm formation and swarming, swimming, and twitching motility in PA14 and some P. aeruginosa isolates. These virulence factors are directly involved with quorum-sensing systems. Further research should investigate the effects of AgNPs on P. aeruginosa quorum sensing to help elucidate their mechanism of action at subinhibitory concentrations.}, } @article {pmid33869078, year = {2021}, author = {Subramoni, S and Muzaki, MZBM and Booth, SCM and Kjelleberg, S and Rice, SA}, title = {N-Acyl Homoserine Lactone-Mediated Quorum Sensing Regulates Species Interactions in Multispecies Biofilm Communities.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {646991}, pmid = {33869078}, issn = {2235-2988}, mesh = {*Acyl-Butyrolactones ; Biofilms ; Pseudomonas ; Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {Bacterial biofilms are important medically, environmentally and industrially and there is a need to understand the processes that govern functional synergy and dynamics of species within biofilm communities. Here, we have used a model, mixed-species biofilm community comprised of Pseudomonas aeruginosa PAO1, Pseudomonas protegens Pf-5 and Klebsiella pneumoniae KP1. This biofilm community displays higher biomass and increased resilience to antimicrobial stress conditions such as sodium dodecyl sulfate and tobramycin, compared to monospecies biofilm populations. P. aeruginosa is present at low proportions in the community and yet, it plays a critical role in community function, suggesting it acts as a keystone species in this community. To determine the factors that regulate community composition, we focused on P. aeruginosa because of its pronounced impact on community structure and function. Specifically, we evaluated the role of the N-acyl homoserine lactone (AHL) dependent quorum sensing (QS) system of P. aeruginosa PAO1, which regulates group behaviors including biofilm formation and the production of effector molecules. We found that mixed species biofilms containing P. aeruginosa QS mutants had significantly altered proportions of K. pneumoniae and P. protegens populations compared to mixed species biofilms with the wild type P. aeruginosa. Similarly, inactivation of QS effector genes, e.g. rhlA and pvdR, also governed the relative species proportions. While the absence of QS did not alter the proportions of the two species in dual species biofilms of P. aeruginosa and K. pneumoniae, it resulted in significantly lower proportions of P. aeruginosa in dual species biofilms with P. protegens. These observations suggest that QS plays an important role in modulating community biofilm structure and physiology and affects interspecific interactions.}, } @article {pmid33868212, year = {2021}, author = {Lyu, X and Li, C and Zhang, J and Wang, L and Jiang, Q and Shui, Y and Chen, L and Luo, Y and Xu, X}, title = {A Novel Small Molecule, LCG-N25, Inhibits Oral Streptococcal Biofilm.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {654692}, pmid = {33868212}, issn = {1664-302X}, abstract = {Dental caries is a chronic oral infectious disease caused by cariogenic biofilm adhered on the tooth surface. Our previous study demonstrated that a repurposed natural compound napabucasin (NAP) showed good antimicrobial activity against oral streptococcal biofilms. The current study designed a novel small molecule, namely LCG-N25, using NAP as a lead compound, and aimed to investigate its potential as an antimicrobial agent in the control of dental caries. LCG-N25 was designed and synthesized with reference to the structure of NAP. The minimal inhibitory concentrations and the minimal bactericidal concentrations of LCG-N25 against Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii were evaluated by microdilution method. The antimicrobial activity of LCG-N25 was further evaluated by crystal violet staining, colony forming units counting, biofilm metabolism assay, dead/live fluorescent staining, and scanning electron microscopy. The effect of LCG-N25 on the extracellular polysaccharides of biofilms was determined by both anthrone-sulfuric acid method and fluorescent staining. The microbial composition of streptococcal biofilms after LCG-N25 treatment was further visualized and quantified by fluorescence in situ hybridization. Besides, the cytotoxicity of LCG-N25 was evaluated by Cell Counting Kit-8 assay, and repeated exposure of S. mutans to LCG-N25 treatment was performed to assess if this novel compound could induce drug resistance of this cariogenic bacterium. We found that LCG-N25 exhibited a good antibacterial activity, low-cytotoxicity, and did not induce drug resistance of cariogenic S. mutans. These findings suggest that LCG-N25 may represent a promising antimicrobial agent that can be used as an adjuvant to the management of dental caries.}, } @article {pmid33867187, year = {2021}, author = {Alonso, B and Pérez-Granda, MJ and Latorre, MC and Sánchez-Carrillo, C and Bouza, E and Muñoz, P and Guembe, M}, title = {Production of biofilm by Staphylococcus aureus: Association with infective endocarditis?.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.eimc.2021.03.012}, pmid = {33867187}, issn = {2529-993X}, abstract = {OBJECTIVES: Staphylococcus aureus is a well-known biofilm-producing pathogen that is capable of causing chronic infections owing to its ability to resist antibiotic treatment and obstruct the immune response. However, the possible association between high biofilm production and infective endocarditis (IE) has not been assessed. Our objective was to compare production of biofilm by S. aureus strains isolated from patients with bacteremia and IE, catheter-related bloodstream infection (C-RBSI), or non-device associated bacteremia.

METHODS: We isolated 260 S. aureus strains from the blood of patients with bacteremia who were diagnosed during hospital admission between 2012 and 2015. Patients were divided into 3 groups according to whether they had IE, C-RBSI, or non-device associated bacteremia. Biofilm production was measured in terms of biomass and metabolic activity using the crystal violet and XTT assays, respectively. High biomass and metabolic activity rates (based on tertile ranks classification) were compared between the 3 groups.

RESULTS: The high biomass and metabolic activity rates of each group were 41.9% and 37.2% for IE, 32.5% and 35.0%, for C-RBSI, and 29.0% and 33.3% for non-device associated bacteremia (p=0.325 and p=0.885, respectively).

CONCLUSIONS: High biomass and metabolic activity levels for S. aureus isolates from IE were similar to those of S. aureus isolates from C-RBSI or non-device associated bacteremia.}, } @article {pmid33866014, year = {2021}, author = {Pourhajibagher, M and Salehi-Vaziri, A and Noroozian, M and Akbar, H and Bazarjani, F and Ghaffari, H and Bahador, A}, title = {An orthodontic acrylic resin containing seaweed Ulva lactuca as a photoactive phytocompound in antimicrobial photodynamic therapy: Assessment of anti-biofilm activities and mechanical properties.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {35}, number = {}, pages = {102295}, doi = {10.1016/j.pdpdt.2021.102295}, pmid = {33866014}, issn = {1873-1597}, mesh = {Acrylic Resins ; Anti-Bacterial Agents ; *Anti-Infective Agents ; Biofilms ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; *Seaweed ; *Ulva ; }, abstract = {BACKGROUND: Uncontrolled accumulation of microbial plaque and formation of biofilm on the surface orthodontic acrylic removable appliances increases the risk of enamel decalcification and periodontal diseases. The purpose of the present study was to evaluate antimicrobial activities, anti-virulence potencies, and mechanical properties of orthodontic acrylic resin containing different concentrations of Ulva lactuca (a green marine macroalga) following photo-activation against Streptococcus mutans.

MATERIALS AND METHODS: Minimum inhibitory concentration (MIC) of U. lactuca was determined against S. mutans. Acrylic resin specimens with different concentrations of U. lactuca (0.2 %, 0.5 %, 1%, 2.5 %, 5%, and 10 % weight/weight) were fabricated. Flexural strength values, antimicrobial effects, and anti-biofilm activities of samples were assessed in comparison with original acrylic resin as the control group. Also, the expression of the virulence-associated genes was assessed by quantitative real-time polymerase chain reaction.

RESULTS: U. lactuca at concentrations of 1-10% significantly reduced the S. mutans growth rate by 20.3%-63.3% in comparison to the control group (P < 0.05). Therefore, the concentration of 1% of U. lactuca was considered as a MIC. The highest and lowest flexural strength values were observed in the control group (43.5 ± 2.4 MPa) and the group with a 10 % concentration of U. lactuca (19.2 ± 1.8 MPa), respectively. Flexural strength values decreased in samples containing 2.5 %, 5%, and 10 % concentrations of U. lactuca in comparison to the control group significantly (P > 0.05). In the disc agar diffusion test, the growth inhabitation zones around samples containing different concentrations of photo-activated U. lactuca ranged from 13 mm to 25 mm in diameter. Interestingly, the anti-biofilm activity of U. lactuca-mediated aPDT against S. mutans was dose-dependent. Additionally, the sub-MIC dose of U. lactuca (0.5 %) following photo-activation could significantly decrease the expression levels of gtfB, gtfC, and gtfD to 4.1-, 5.3-, and 7.4-fold, respectively.

CONCLUSIONS: Adding photo-activated U. lactuca to the orthodontic acrylic resin at a concentration of 1% increases its antibacterial and anti-biofilm activities besides not detrimentally affects its flexural strength.}, } @article {pmid33865158, year = {2021}, author = {Han, F and Zhang, M and Liu, Z and Shang, H and Li, Q and Zhou, W}, title = {Dynamic characteristics of microbial community and soluble microbial products in partial nitrification biofilm system developed from marine sediments treating high salinity wastewater.}, journal = {Journal of environmental management}, volume = {290}, number = {}, pages = {112586}, doi = {10.1016/j.jenvman.2021.112586}, pmid = {33865158}, issn = {1095-8630}, mesh = {Biofilms ; Bioreactors ; Extracellular Polymeric Substance Matrix ; Geologic Sediments ; *Microbiota ; *Nitrification ; Nitrogen ; Nitrosomonas ; Salinity ; Sewage ; Wastewater ; }, abstract = {High salinity wastewater generally resulted in microorganism death and low treatment efficiency of nutrient in conventional activity sludge system. Marine sediments, containing a huge amount of natural salt-tolerant microorganisms, provide a feasible option for the rapid construction of halophilic biological treatment system. However, the dynamic of native microorganisms and the fate of soluble microbial products (SMP) in halophilic biofilm system developed from marine sediments needs to be further studied. In this study, a partial nitrification system was successfully established by inoculation of marine sediments in sequential batch biofilm reactor. Satisfactory chemical oxygen demand (COD) and NH4[+]-N removal efficiency (95% and 99%) and nitrite accumulation rate (NAR) (>90%) was achieved for treatment of synthetic seawater blackwater. High cell surface hydrophobicity (CSH) and proteins to polysaccharide ratio of extracellular polymeric substance (EPS) were beneficial to the initial biofilm formation. High-throughput sequencing results revealed Nitrosomonas halophila was the sole ammonia oxidizing bacteria (AOB). Thauera and Paracoccus were the main denitrifying bacteria in three biofilm samples. Excitation emission matrix (EEM) spectroscopy coupled with parallel factor analysis (PARAFAC) clarified that proteins were significantly degraded than the other two components (humic-like and fulvic acid-like substance). This study will provide a feasible approach for developing halophilic biological treatment system and present an in-depth insight of the dynamic characteristics of SMP in partial nitrification biofilm system.}, } @article {pmid33864459, year = {2021}, author = {Wasa, A and Land, JG and Gorthy, R and Krumdieck, S and Bishop, C and Godsoe, W and Heinemann, JA}, title = {Antimicrobial and biofilm-disrupting nanostructured TiO2 coating demonstrating photoactivity and dark activity.}, journal = {FEMS microbiology letters}, volume = {368}, number = {7}, pages = {}, doi = {10.1093/femsle/fnab039}, pmid = {33864459}, issn = {1574-6968}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Nanostructures/*chemistry/ultrastructure ; Photochemical Processes ; Saccharomyces cerevisiae/drug effects ; Surface Properties ; Titanium/*chemistry/pharmacology ; }, abstract = {Antimicrobial materials are tools used to reduce the transmission of infectious microorganisms. Photo-illuminated titania (TiO2) is a known antimicrobial material. Used as a coating on door handles and similar surfaces, it may reduce viability and colonization by pathogens and limit their spread. We tested the survival of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Saccharomyces cerevisiae on a nano-structured TiO2-based thin film, called 'NsARC', and on stainless steel under a variety of light wavelengths and intensities. There was significantly less survival (P <0.001) of all the organisms tested on NsARC compared to inert uncoated stainless steel under all conditions. NsARC was active in the dark and possible mechanisms for this are suggested. NsARC inhibited biofilm formation as confirmed by scanning electron microscopy. These results suggest that NsARC can be used as a self-cleaning and self-sterilizing antimicrobial surface coating for the prevention and reduction in the spread of potentially infectious microbes.}, } @article {pmid33864216, year = {2021}, author = {Gorodylova, N and Michel, C and Seron, A and Joulian, C and Delorme, F and Bresch, S and Garreau, C and Giovannelli, F and Michel, K}, title = {Modified zeolite-supported biofilm in service of pesticide biodegradation.}, journal = {Environmental science and pollution research international}, volume = {28}, number = {33}, pages = {45296-45316}, pmid = {33864216}, issn = {1614-7499}, support = {APR 2016 BIOPEPS//Conseil Régional du Centre-Val de Loire/ ; }, mesh = {Biodegradation, Environmental ; Biofilms ; *Cupriavidus ; *Pesticides ; RNA, Ribosomal, 16S ; Soil Microbiology ; *Soil Pollutants ; *Zeolites ; }, abstract = {The development of biofilms on modified natural zeolites was investigated with purpose to obtain biocomposites with biodegradation activity towards pesticides MCPA (2-methyl-4-chlorophenoxyacetic acid) and glyphosate (N-(phosphonomethyl)glycine) for potential application in bioaugmentation of polluted agricultural soils. Microbial communities were selected from agricultural pesticide-contaminated soil/water samples and enriched on the basis of their ability to biodegrade the pesticides. In order to enhance affinity of microbial communities to the support material, the natural mineral zeolite was modified by nontoxic environmentally friendly cations (Li[+], Na[+], K[+], NH4[+], H[+], Mg[2+], Ca[2+], Fe[3+]) by methods preserving its structure and characterised using powder XRD, surface area measurement and chemical composition analysis. Kinetics of pesticide degradation by the biocomposites was studied in liquid media. Results showed that according to zeolite modifications, the microbial activity and biodiversity changed. The best biodegradation rate of MCPA and glyphosate reached 0.12-0.13 mg/h with half-life of 16-18 h, which is considerably quicker than observed in natural environment. However, in some cases, biodegradation activity towards pesticides was lost which was connected to unfavourable zeolite modification and accumulation of toxic metabolites. High-throughput sequencing on the 16S rRNA genes of the biofilm communities highlighted the selection of bacteria genera known to metabolise MCPA (Aminobacter, Cupriavidus, Novosphingobium, Pseudomonas, Rhodococcus, Sphingobium and Sphingopyxis) and glyphosate (Pseudomonas). Altogether, results suggested that zeolites do not only have a passive role of biofilm support but also have protective and nutrient-supportive functions that consequently increase biodiversity of the pesticide degraders growing in the biofilm and influence the pesticide biodegradation rate.}, } @article {pmid33864127, year = {2021}, author = {Dos Santos, CED and Costa, RB and Rabelo, CABS and Ferraz Júnior, ADN and Persinoti, GF and Pozzi, E and Foresti, E and Damianovic, MHRZ}, title = {Hacking biofilm developed in a structured-bed reactor (SBRRIA) with integrated processes of nitrogen and organic matter removal.}, journal = {Bioprocess and biosystems engineering}, volume = {44}, number = {9}, pages = {1841-1851}, pmid = {33864127}, issn = {1615-7605}, support = {2013/15665-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2015/21650-9//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, mesh = {*Anaerobic Ammonia Oxidation ; Bacteria/*growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Bioreactors ; *Denitrification ; *Microbiota ; Nitrogen/*metabolism ; }, abstract = {Biomass samples from a structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) were analyzed to investigate the bacterial community shift along with the changes in the C/N ratio. The C/N ratios tested were 7.6 ± 1.0 (LNC) and 2.9 ± 0.4 (HNC). The massive sequencing analyses revealed that the microbial community adjusted itself to different organic and nitrogenous applied loads, with no harm to reactor performance regarding COD and Total-N removal. Under LNC, conventional nitrification and heterotrophic denitrification steered the process, as indicated by the detection of microorganisms affiliated with Nitrosomonadaceae, Nitrospiraceae, and Rhodocyclaceae families. However, under HNC, the C/N ratio strongly affected the microbial community, resulting in the prevalence of members of Saprospiraceae, Chitinophagaceae, Xanthomonadaceae, Comamonadaceae, Bacillaceae, and Planctomycetaceae. These families include bacteria capable of using organic matter derived from cell lysis, ammonia-oxidizers under low DO, heterotrophic nitrifiers-aerobic denitrifiers, and non-isolated strains of Anammox. The DO profile confirmed that the stratification in aerobic, anoxic, and anaerobic zones enabled the establishment of different nitrogen degradation pathways, including the Anammox.}, } @article {pmid33863914, year = {2021}, author = {Beebout, CJ and Sominsky, LA and Eberly, AR and Van Horn, GT and Hadjifrangiskou, M}, title = {Cytochrome bd promotes Escherichia coli biofilm antibiotic tolerance by regulating accumulation of noxious chemicals.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {35}, pmid = {33863914}, issn = {2055-5008}, support = {F30 AI150077/AI/NIAID NIH HHS/United States ; T32 GM007347/GM/NIGMS NIH HHS/United States ; R01 AI107052/AI/NIAID NIH HHS/United States ; P20 DK123967/DK/NIDDK NIH HHS/United States ; }, mesh = {Alleles ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Cytochrome b Group/*genetics/metabolism ; Dose-Response Relationship, Drug ; *Drug Resistance, Bacterial ; Electron Transport Chain Complex Proteins/*genetics/metabolism ; Escherichia coli Proteins/*genetics/metabolism ; Gene Knockdown Techniques ; Microbial Sensitivity Tests ; Oxidoreductases/*genetics/metabolism ; Plankton/drug effects/genetics ; Uropathogenic Escherichia coli/drug effects/*physiology ; }, abstract = {Nutrient gradients in biofilms cause bacteria to organize into metabolically versatile communities capable of withstanding threats from external agents including bacteriophages, phagocytes, and antibiotics. We previously determined that oxygen availability spatially organizes respiration in uropathogenic Escherichia coli biofilms, and that the high-affinity respiratory quinol oxidase cytochrome bd is necessary for extracellular matrix production and biofilm development. In this study we investigate the physiologic consequences of cytochrome bd deficiency in biofilms and determine that loss of cytochrome bd induces a biofilm-specific increase in expression of general diffusion porins, leading to elevated outer membrane permeability. In addition, loss of cytochrome bd impedes the proton mediated efflux of noxious chemicals by diminishing respiratory flux. As a result, loss of cytochrome bd enhances cellular accumulation of noxious chemicals and increases biofilm susceptibility to antibiotics. These results identify an undescribed link between E. coli biofilm respiration and stress tolerance, while suggesting the possibility of inhibiting cytochrome bd as an antibiofilm therapeutic approach.}, } @article {pmid33860563, year = {2021}, author = {Dewake, N and Ma, X and Sato, K and Nakatsu, S and Yoshimura, K and Eshita, Y and Fujinaka, H and Yano, Y and Yoshinari, N and Yoshida, A}, title = {β-Glycyrrhetinic acid inhibits the bacterial growth and biofilm formation by supragingival plaque commensals.}, journal = {Microbiology and immunology}, volume = {65}, number = {9}, pages = {343-351}, doi = {10.1111/1348-0421.12884}, pmid = {33860563}, issn = {1348-0421}, support = {//Kao Corporation/ ; Scientific Research (B) (grant number 18H02974)//Japan Society for the Promotion of Science/ ; }, mesh = {Biofilms ; *Glycyrrhetinic Acid/pharmacology ; Humans ; Streptococcus gordonii ; Streptococcus mutans ; Streptococcus sobrinus ; }, abstract = {β-Glycyrrhetinic acid (BGA) is a natural antibacterial agent. Previous studies reported that BGA has antibacterial effects against several bacteria. This study evaluated the effects of BGA on the regulation of supragingival plaque bacteria. First, the minimum inhibitory concentrations (MICs) of BGA against oral bacteria were measured. Next, the minimum concentrations for inhibition of biofilm formation were evaluated against Streptococcus mutans and Streptococcus sobrinus, possessing insoluble glucan synthesis abilities. The MICs of biofilm formation by these bacteria ranged from 1/8 to 2× MIC. Furthermore, the inhibition effects of BGA against the coaggregation of Porphyromonas gingivalis and Streptococcus gordonii were evaluated. BGA at 32 or 64 μg/mL inhibited the coaggregation of these bacteria after a 30 min incubation. Lastly, the inhibition effects of BGA against human supragingival plaque bacteria were evaluated. Human supragingival plaque samples were obtained from 12 healthy donors. The inhibition effects of BGA against biofilm formation by these plaque bacteria were evaluated. Of 12 samples, the biofilm formation by 11 was significantly attenuated by 128-256 μg/mL of BGA. The number of colony forming units in these biofilms was also significantly attenuated. In conclusion, it was revealed that BGA inhibits the growth and biofilm formation of bacteria, furthermore, the same effect was confirmed with supragingival plaque bacteria. BGA is a good candidate for a natural agent that prevents the outbreak and progression of periodontal disease because it suppresses not only the growth and biofilm formation of bacteria, but also the coaggregation of P. gingivalis with plaque bacteria.}, } @article {pmid33860052, year = {2021}, author = {Sun, Y and Jiang, W and Zhang, M and Zhang, L and Shen, Y and Huang, S and Li, M and Qiu, W and Pan, Y and Zhou, L and Zhang, K}, title = {The Inhibitory Effects of Ficin on Streptococcus mutans Biofilm Formation.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {6692328}, pmid = {33860052}, issn = {2314-6141}, mesh = {Biofilms/*growth & development ; Biomass ; Colony Count, Microbial ; Ficain/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Lactic Acid/biosynthesis ; Microbial Viability/drug effects ; Polysaccharides, Bacterial/biosynthesis ; RNA, Messenger/genetics/metabolism ; Streptococcus mutans/drug effects/metabolism/*physiology/ultrastructure ; }, abstract = {To investigate the effects of ficin on biofilm formation of conditionally cariogenic Streptococcus mutans (S. mutans). Biomass and metabolic activity of biofilm were assessed using crystal violet assay, colony-forming unit (CFU) counting, and MTT assay. Extracellular polysaccharide (EPS) synthesis was displayed by SEM imaging, bacteria/EPS staining, and anthrone method while acid production was revealed by lactic acid assay. Growth curve and live/dead bacterial staining were conducted to monitor bacterial growth state in both planktonic and biofilm form. Total protein and extracellular proteins of S. mutans biofilm were analyzed by protein/bacterial staining and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), severally. qRT-PCR was conducted to detect acid production, acid tolerance, and biofilm formation associated genes. Crystal violet assay, CFU counting, and MTT assay showed that the suppression effect of ficin on S. mutans biofilm formation was concentration dependent. 4 mg/mL ficin had significant inhibitory effect on S. mutans biofilm formation including biomass, metabolic activity, EPS synthesis, and lactic acid production (p < 0.05). The growth curves from 0 mg/mL to 4 mg/mL ficin were aligned with each other. There was no significant difference among different ficin groups in terms of live/dead bacterial staining result (p > 0.05). Protein/bacterial staining outcome indicated that ficin inhibit both total protein and biofilm formation during the biofilm development. There were more relatively small molecular weight protein bands in extracellular proteins of 4 mg/mL ficin group when compared with the control. Generally, ficin could inhibit biofilm formation and reduce cariogenic virulence of S. mutans effectively in vitro; thus, it could be a potential anticaries agent.}, } @article {pmid33859338, year = {2021}, author = {Panariello, BHD and Kindler, JK and Spolnik, KJ and Ehrlich, Y and Eckert, GJ and Duarte, S}, title = {Use of electromagnetic stimulation on an Enterococcus faecalis biofilm on root canal treated teeth in vitro.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {8306}, pmid = {33859338}, issn = {2045-2322}, mesh = {Biofilms/drug effects/*radiation effects ; Dental Pulp Cavity/*microbiology ; Disinfection/*methods ; *Electromagnetic Radiation ; Enterococcus faecalis/*physiology ; Humans ; In Vitro Techniques ; Root Canal Therapy/*methods ; Saline Solution/pharmacology ; Sodium Hypochlorite/pharmacology ; }, abstract = {Root canal disinfection is of utmost importance in the success of the treatment, thus, a novel method for achieving root canal disinfection by electromagnetic waves, creating a synergistic reaction via electric and thermal energy, was created. To study electromagnetic stimulation (EMS) for the disinfection of root canal in vitro, single rooted teeth were instrumented with a 45.05 Wave One Gold reciprocating file. Specimens were sterilized and inoculated with Enterococcus faecalis ATCC 29,212, which grew for 15 days to form an established biofilm. Samples were treated with 6% sodium hypochlorite (NaOCl), 1.5% NaOCl 1.5% NaOCl with EMS, 0.9% saline with EMS or 0.9% saline. After treatments, the colony forming units (CFU) was determined. Data was analyzed by Wilcoxon Rank Sums Test (α = 0.05). One sample per group was scored and split for confocal laser scanning microscopy imaging. There was a significant effect with the use of NaOCl with or without EMS versus 0.9% saline with or without EMS (p = 0.012 and 0.003, respectively). CFUs were lower when using 0.9% saline with EMS versus 0.9% saline alone (p = 0.002). Confocal imaging confirmed CFU findings. EMS with saline has an antibiofilm effect against E. faecalis and can potentially be applied for endodontic disinfection.}, } @article {pmid33859234, year = {2021}, author = {Vyas, HKN and McArthur, JD and Sanderson-Smith, ML}, title = {An optimised GAS-pharyngeal cell biofilm model.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {8200}, pmid = {33859234}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Calibration ; Cell Culture Techniques/standards ; Cells, Cultured ; Humans ; Microbiological Techniques/standards ; Models, Biological ; Pharynx/cytology/*microbiology ; Streptococcal Infections/microbiology ; Streptococcus pyogenes/growth & development/pathogenicity/*physiology ; Virulence Factors/metabolism ; }, abstract = {Group A Streptococcus (GAS) causes 700 million infections and accounts for half a million deaths per year. Biofilm formation has been implicated in both pharyngeal and dermal GAS infections. In vitro, plate-based assays have shown that several GAS M-types form biofilms, and multiple GAS virulence factors have been linked to biofilm formation. Although the contributions of these plate-based studies have been valuable, most have failed to mimic the host environment, with many studies utilising abiotic surfaces. GAS is a human specific pathogen, and colonisation and subsequent biofilm formation is likely facilitated by distinct interactions with host tissue surfaces. As such, a host cell-GAS model has been optimised to support and grow GAS biofilms of a variety of GAS M-types. Improvements and adjustments to the crystal violet biofilm biomass assay have also been tailored to reproducibly detect delicate GAS biofilms. We propose 72 h as an optimal growth period for yielding detectable biofilm biomass. GAS biofilms formed are robust and durable, and can be reproducibly assessed via staining/washing intensive assays such as crystal violet with the aid of methanol fixation prior to staining. Lastly, SEM imaging of GAS biofilms formed by this model revealed GAS cocci chains arranged into three-dimensional aggregated structures with EPS matrix material. Taken together, we outline an efficacious GAS biofilm pharyngeal cell model that can support long-term GAS biofilm formation, with biofilms formed closely resembling those seen in vivo.}, } @article {pmid33858087, year = {2021}, author = {Duong, TH and Park, JW and Maeng, SK}, title = {Assessment of organic carbon migration and biofilm formation potential on polymeric tubes in contact with water.}, journal = {Journal of hazardous materials}, volume = {411}, number = {}, pages = {125095}, doi = {10.1016/j.jhazmat.2021.125095}, pmid = {33858087}, issn = {1873-3336}, mesh = {Biofilms ; *Carbon ; *Drinking Water ; Humans ; Water Microbiology ; Water Supply ; }, abstract = {Biofilm formation has been frequently identified as a pathway of nosocomial infection in polymeric tubes used for patients of all ages. Biofilm formation on tube surfaces can lead to hygienic failure and cause diarrhea, stomach pain, inflammation, and digestive system disease. This study investigated the influence of polymeric tube materials in contact with water on the biomass formation potential and migration potential of microbially available carbon from plasticizers using a BioMig test. The thermoplastic elastomer tube, which is reusable, leached a relatively low amount of assimilable organic carbon to water. In contrast, the assimilable organic carbon migration potential of polyurethane was the most significant, 6-fold greater than that of the thermoplastic elastomer. Moreover, the same materials (e.g., silicone) produced via different manufacturing processes showed significant differences in migration behaviors. The potential biomass formation observed in polyurethane was approximately 7 × 10[9] cells cm[-2] for both Aeromonas hydrophila and Escherichia coli strains. This study highlights the importance of choosing the correct material characteristics of polymeric tubes in contact with water to protect them from bacterial contamination. Therefore, manufacturers can use the BioMig test to evaluate and produce more hygienic and biostable tubes.}, } @article {pmid33857927, year = {2021}, author = {D'Agostino, A and Tana, F and Ettorre, A and Pavarini, M and Serafini, A and Cochis, A and Scalia, AC and Rimondini, L and De Giglio, E and Cometa, S and Chiesa, R and De Nardo, L}, title = {Mesoporous zirconia surfaces with anti-biofilm properties for dental implants.}, journal = {Biomedical materials (Bristol, England)}, volume = {16}, number = {4}, pages = {}, doi = {10.1088/1748-605X/abf88d}, pmid = {33857927}, issn = {1748-605X}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Cells, Cultured ; *Coated Materials, Biocompatible/chemistry/pharmacology ; Coculture Techniques ; *Dental Implants ; Fibroblasts/cytology ; Gallium ; Gingiva/cytology ; Humans ; Osteoblasts/cytology ; Surface Properties ; *Zirconium/chemistry/pharmacology ; }, abstract = {Cytocompatible bioactive surface treatments conferring antibacterial properties to osseointegrated dental implants are highly requested to prevent bacteria-related peri-implantitis. Here we focus on a newly designed family of mesoporous coatings based on zirconia (ZrO2) microstructure doped with gallium (Ga), exploiting its antibacterial and pro-osseo-integrative properties. The ZrO2films were obtained via sol-gel synthesis route using Pluronic F127 as templating agent, while Ga doping was gained by introducing gallium nitrate hydrate. Chemical characterization by means of x-ray photoelectron spectroscopy and glow discharge optical emission spectroscopy confirmed the effective incorporation of Ga. Then, coatings morphological and structural analysis were carried out by transmission electron microscopy and selected area electron diffraction unveiling an effective stabilization of both the mesoporous structure and the tetragonal ZrO2phase. Specimens' cytocompatibility was confirmed towards gingival fibroblast and osteoblasts progenitors cultivated directly onto the coatings showing comparable metabolic activity and morphology in respect to controls cultivated on polystyrene. The presence of Ga significantly reduced the metabolic activity of the adhered oral pathogensPorphyromonas gingivalisandAggregatibacter actinomycetemcomitansin comparison to untreated bulk zirconia (p< 0.05); on the opposite, Ga ions did not significantly reduce the metabolism of the oral commensalStreptococcus salivarius(p> 0.05) thus suggesting for a selective anti-pathogens activity. Finally, the coatings' ability to preserve cells from bacterial infection was proved in a co-culture method where cells and bacteria were cultivated in the same environment: the presence of Ga determined a significant reduction of the bacteria viability while allowing at the same time for cells proliferation. In conclusion, the here developed coatings not only demonstrated to satisfy the requested antibacterial and cytocompatibility properties, but also being promising candidates for the improvement of implantable devices in the field of implant dentistry.}, } @article {pmid33857401, year = {2021}, author = {Del Pozo, JL}, title = {Novel treatment dynamics for biofilm-related infections.}, journal = {Expert review of anti-infective therapy}, volume = {19}, number = {11}, pages = {1443-1456}, doi = {10.1080/14787210.2021.1917993}, pmid = {33857401}, issn = {1744-8336}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology/therapeutic use ; *Biofilms ; Humans ; }, abstract = {Introduction: As a result of progress in medical care, a huge number of medical devices are used in the treatment of human diseases. In turn, biofilm-related infection has become a growing threat due to the tolerance of biofilms to antimicrobials, a problem magnified by the development of antimicrobial resistance worldwide. As a result, successful treatment of biofilm-disease using only antimicrobials is problematic.Areas covered: We summarize some alternative approaches to classic antimicrobials for the treatment of biofilm disease. This review is not intended to be exhaustive but to give a clinical picture of alternatives to antimicrobial agents to manage biofilm disease. We highlight those strategies that may be closer to application in clinical practice.Expert opinion: There are a number of outstanding challenges in the development of novel antibiofilm therapies. Screening for effective antibiofilm compounds requires models relevant to all clinical scenarios. Although in vitro research of anti-biofilm strategies has progressed significantly over the past decade, there is a lack of in vivo research. In addition, the complexity of biofilm biology makes it difficult to develop a compound that is likely to provide the single 'magic bullet'. The multifaceted nature of biofilms imposes the need for multi-targeted or combinatorial therapies.}, } @article {pmid33856931, year = {2021}, author = {Astrada, A and Nakagami, G and Minematsu, T and Goto, T and Kitamura, A and Mugita, Y and Sanada, H}, title = {Concurrent validity of biofilm detection by wound blotting on hard-to-heal wounds.}, journal = {Journal of wound care}, volume = {30}, number = {Sup4}, pages = {S4-S13}, doi = {10.12968/jowc.2021.30.Sup4.S4}, pmid = {33856931}, issn = {0969-0700}, mesh = {Bandages ; *Biofilms ; Humans ; Pseudomonas aeruginosa ; Surgical Wound Infection ; Treatment Outcome ; *Wound Healing ; Wound Infection/diagnosis/*therapy ; }, abstract = {OBJECTIVE: Wound biofilms delay healing of hard-to-heal wounds. Convenient biofilm identification tools for clinical settings are currently not available, hindering biofilm-based wound management. Wound blotting with biofilm staining is a potential tool for biofilm detection, owing to its convenience. Although predictive validity of wound blotting has been established, it is necessary to confirm its concurrent validity. Furthermore, current staining systems employing ruthenium red have some disadvantages for clinical use. This study aimed to evaluate the usability of alcian blue as a substitute for ruthenium red.

METHOD: Both in vitro and in vivo clinical samples were used to investigate validity and usability.

RESULTS: The in vitro study showed that proteins and extracellular DNA in biofilms did not affect staining ability of ruthenium red and alcian blue in the detection of biofilms. In the in vivo study, using a wound biofilm model with Pseudomonas aeruginosa, the staining sensitivity of ruthenium red was 88.9% and 100% for alcian blue, with correlation coefficients of signal intensities with native polyacrylamide gel electrophoresis (PAGE) of r=0.67 (p=0.035) and r=0.67 (p=0.036) for ruthenium red and alcian blue, respectively. Results from clinical samples were r=0.75 (p=0.001) for ruthenium red and r=0.77 (p<0.001) for alcian blue. The sensitivities of wound blotting staining by ruthenium red and alcian blue were very high and had a good correlation with native PAGE analysis.

CONCLUSION: Because the alcian blue procedure is more convenient than the ruthenium red procedure, wound blotting with alcian blue staining would be a promising tool to guide clinicians in delivering biofilm-based wound management.}, } @article {pmid33856558, year = {2021}, author = {Ford, N and Fisher, G and Prindle, A and Chopp, D}, title = {A Two-Dimensional Model of Potassium Signaling and Oscillatory Growth in a Biofilm.}, journal = {Bulletin of mathematical biology}, volume = {83}, number = {5}, pages = {60}, pmid = {33856558}, issn = {1522-9602}, support = {T32 GM008061/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacillus subtilis/physiology ; *Bacterial Physiological Phenomena ; *Biofilms ; *Models, Biological ; *Potassium/metabolism ; *Signal Transduction ; }, abstract = {Biofilms are complex communities of bacteria that exhibit a variety of collective behaviors. These behaviors improve their ability to survive in many different environments. One of these collective behaviors seen in Bacillus subtilis is the ability for starving cells to stop the growth of other cells using potassium signaling and voltage changes. This signaling produces an oscillatory growth pattern so that during periods of low growth the nutrients diffuse deeper into the biofilm and reach the nutrient-starved, interior regions of the biomass. In this paper, we develop a mathematical model to describe this oscillatory behavior, and we use this model to develop a two-dimensional simulation that reproduces many of the important features seen in the experimental data. This simulation allows us to examine the spatial patterning of the oscillatory behavior to better understand the relationships between the various regions of the biofilm. Studying the spatial components of the metabolic and voltage oscillations could allow for the development of new control techniques for biofilms with complex shapes.}, } @article {pmid33856484, year = {2021}, author = {Sedlmayer, F and Woischnig, AK and Unterreiner, V and Fuchs, F and Baeschlin, D and Khanna, N and Fussenegger, M}, title = {5-Fluorouracil blocks quorum-sensing of biofilm-embedded methicillin-resistant Staphylococcus aureus in mice.}, journal = {Nucleic acids research}, volume = {49}, number = {13}, pages = {e73}, pmid = {33856484}, issn = {1362-4962}, support = {785800/ERC_/European Research Council/International ; }, mesh = {Animals ; Bacterial Proteins/antagonists & inhibitors ; Biofilms/*drug effects ; Carbon-Sulfur Lyases/antagonists & inhibitors ; Enzyme Inhibitors/*pharmacology/therapeutic use ; Female ; Fluorouracil/*pharmacology/therapeutic use ; HEK293 Cells ; High-Throughput Screening Assays/*methods ; Homoserine/analogs & derivatives/biosynthesis ; Humans ; Lactones ; Methicillin-Resistant Staphylococcus aureus/*drug effects/metabolism ; Mice, Inbred C57BL ; N-Glycosyl Hydrolases/antagonists & inhibitors ; Quorum Sensing/*drug effects ; Small Molecule Libraries ; Staphylococcal Infections/prevention & control ; }, abstract = {Antibiotic-resistant pathogens often escape antimicrobial treatment by forming protective biofilms in response to quorum-sensing communication via diffusible autoinducers. Biofilm formation by the nosocomial pathogen methicillin-resistant Staphylococcus aureus (MRSA) is triggered by the quorum-sensor autoinducer-2 (AI-2), whose biosynthesis is mediated by methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) and S-ribosylhomocysteine lyase (LuxS). Here, we present a high-throughput screening platform for small-molecular inhibitors of either enzyme. This platform employs a cell-based assay to report non-toxic, bioavailable and cell-penetrating inhibitors of AI-2 production, utilizing engineered human cells programmed to constitutively secrete AI-2 by tapping into the endogenous methylation cycle via ectopic expression of codon-optimized MTAN and LuxS. Screening of a library of over 5000 commercial compounds yielded 66 hits, including the FDA-licensed cytostatic anti-cancer drug 5-fluorouracil (5-FU). Secondary screening and validation studies showed that 5-FU is a potent quorum-quencher, inhibiting AI-2 production and release by MRSA, Staphylococcus epidermidis, Escherichia coli and Vibrio harveyi. 5-FU efficiently reduced adherence and blocked biofilm formation of MRSA in vitro at an order-of-magnitude-lower concentration than that clinically relevant for anti-cancer therapy. Furthermore, 5-FU reestablished antibiotic susceptibility and enabled daptomycin-mediated prevention and clearance of MRSA infection in a mouse model of human implant-associated infection.}, } @article {pmid33856344, year = {2021}, author = {Bridges, AA and Bassler, BL}, title = {Inverse regulation of Vibrio cholerae biofilm dispersal by polyamine signals.}, journal = {eLife}, volume = {10}, number = {}, pages = {}, pmid = {33856344}, issn = {2050-084X}, support = {DRG-2302-17/DRCRF/Damon Runyon Cancer Research Foundation/United States ; 5R37GM065859/NH/NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; MCB-1713731//National Science Foundation/ ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/*metabolism ; *Biofilms ; Polyamines/*metabolism ; *Signal Transduction ; Vibrio cholerae/*physiology ; }, abstract = {The global pathogen Vibrio cholerae undergoes cycles of biofilm formation and dispersal in the environment and the human host. Little is understood about biofilm dispersal. Here, we show that MbaA, a periplasmic polyamine sensor, and PotD1, a polyamine importer, regulate V. cholerae biofilm dispersal. Spermidine, a commonly produced polyamine, drives V. cholerae dispersal, whereas norspermidine, an uncommon polyamine produced by vibrios, inhibits dispersal. Spermidine and norspermidine differ by one methylene group. Both polyamines control dispersal via MbaA detection in the periplasm and subsequent signal relay. Our results suggest that dispersal fails in the absence of PotD1 because endogenously produced norspermidine is not reimported, periplasmic norspermidine accumulates, and it stimulates MbaA signaling. These results suggest that V. cholerae uses MbaA to monitor environmental polyamines, blends of which potentially provide information about numbers of 'self' and 'other'. This information is used to dictate whether or not to disperse from biofilms.}, } @article {pmid33852903, year = {2021}, author = {Malishev, R and Salinas, N and Gibson, J and Eden, AB and Mieres-Perez, J and Ruiz-Blanco, YB and Malka, O and Kolusheva, S and Klärner, FG and Schrader, T and Sanchez-Garcia, E and Wang, C and Landau, M and Bitan, G and Jelinek, R}, title = {Inhibition of Staphylococcus aureus biofilm-forming functional amyloid by molecular tweezers.}, journal = {Cell chemical biology}, volume = {28}, number = {9}, pages = {1310-1320.e5}, pmid = {33852903}, issn = {2451-9448}, support = {R01 AG050721/AG/NIA NIH HHS/United States ; RF1 AG054000/AG/NIA NIH HHS/United States ; }, mesh = {Amyloid/*antagonists & inhibitors/metabolism ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Toxins/*antagonists & inhibitors/metabolism ; Biofilms/*drug effects ; Hemolysin Proteins/*antagonists & inhibitors/metabolism ; Microbial Sensitivity Tests ; Optical Tweezers ; Staphylococcus aureus/*drug effects/metabolism ; }, abstract = {Biofilms are rigid and largely impenetrable three-dimensional matrices constituting virulence determinants of various pathogenic bacteria. Here, we demonstrate that molecular tweezers, unique supramolecular artificial receptors, modulate biofilm formation of Staphylococcus aureus. In particular, the tweezers affect the structural and assembly properties of phenol-soluble modulin α1 (PSMα1), a biofilm-scaffolding functional amyloid peptide secreted by S. aureus. The data reveal that CLR01, a diphosphate tweezer, exhibits significant S. aureus biofilm inhibition and disrupts PSMα1 self-assembly and fibrillation, likely through inclusion of lysine side chains of the peptide. In comparison, different peptide binding occurs in the case of CLR05, a tweezer containing methylenecarboxylate units, which exhibits lower affinity for the lysine residues yet disrupts S. aureus biofilm more strongly than CLR01. Our study points to a possible role for molecular tweezers as potent biofilm inhibitors and antibacterial agents, particularly against untreatable biofilm-forming and PSM-producing bacteria, such as methicillin-resistant S. aureus.}, } @article {pmid33852023, year = {2021}, author = {Zhang, D and Wang, F and Yu, Y and Ding, S and Chen, T and Sun, W and Liang, C and Yu, B and Ying, H and Liu, D and Chen, Y}, title = {Effect of quorum-sensing molecule 2-phenylethanol and ARO genes on Saccharomyces cerevisiae biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {9}, pages = {3635-3648}, pmid = {33852023}, issn = {1432-0614}, support = {SBK2017010373//National Outstanding Youth Science Fund Project of National Natural Science Foundation of China/ ; IRT_14R28//Changjiang Scholar Program of Chinese Ministry of Education/ ; 2018YFA0902200;2018YFA0902200//National Key Research and Development Program of China/ ; BE2014715//the Technology Support Program of Jiangsu/ ; }, mesh = {Biofilms ; *Phenylethyl Alcohol ; Quorum Sensing ; Saccharomyces cerevisiae/genetics ; *Saccharomyces cerevisiae Proteins/genetics ; Transaminases ; }, abstract = {Biofilms are a form of microbial community that can be beneficial for industrial fermentation because of their remarkable environmental resistance. However, the mechanism of biofilm formation in Saccharomyces cerevisiae remains to be fully explored, and this may enable improved industrial applications for this organism. Although quorum-sensing (QS) molecules are known to be involved in bacteria biofilm formation, few studies have been undertaken with these in fungi. 2-phenylethanol (2-PE) is considered a QS molecule in S. cerevisiae. Here, we found that exogenous 2-PE could stimulate biofilm formation at low cell concentrations. ARO8p and ARO9p are responsible for the synthesis of 2-PE and were crucial to the formation of biofilm. Deletion of the ARO8 and ARO9 genes reduced the content of 2-PE in the early stage of fermentation, reduced ethanol yield and decreased biofilm formation. The expression of FLOp, which is involved in cell adhesion, and the content of extracellular polysaccharides of mutant strains ΔARO8 and ΔARO9 were also significantly reduced. These findings indicate that the production of 2-PE had a positive effect on biofilm formation in S. cerevisiae, thereby providing further key details for studying the formation of biofilm mechanism in the future. KEY POINTS: • Quorum-sensing molecule 2-PE positively affects biofilm formation in S. cerevisiae. • 2-PE synthetic genes ARO8 and ARO9 deletion reduced extracellular polysaccharide. • ARO8 and ARO9 deletion reduced the gene expression of the FLO family.}, } @article {pmid33850153, year = {2021}, author = {Barraud, N and Létoffé, S and Beloin, C and Vinh, J and Chiappetta, G and Ghigo, JM}, title = {Lifestyle-specific S-nitrosylation of protein cysteine thiols regulates Escherichia coli biofilm formation and resistance to oxidative stress.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {34}, pmid = {33850153}, issn = {2055-5008}, mesh = {Amino Acids/metabolism ; Biofilms/*growth & development ; Cysteine/metabolism ; Escherichia coli/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Homeostasis ; Mutation ; Oxidation-Reduction ; *Oxidative Stress ; Phenotype ; *Protein Processing, Post-Translational ; Proteome ; Proteomics/methods ; Sulfhydryl Compounds/metabolism ; }, abstract = {Communities of bacteria called biofilms are characterized by reduced diffusion, steep oxygen, and redox gradients and specific properties compared to individualized planktonic bacteria. In this study, we investigated whether signaling via nitrosylation of protein cysteine thiols (S-nitrosylation), regulating a wide range of functions in eukaryotes, could also specifically occur in biofilms and contribute to bacterial adaptation to this widespread lifestyle. We used a redox proteomic approach to compare cysteine S-nitrosylation in aerobic and anaerobic biofilm and planktonic Escherichia coli cultures and we identified proteins with biofilm-specific S-nitrosylation status. Using bacterial genetics and various phenotypic screens, we showed that impairing S-nitrosylation in proteins involved in redox homeostasis and amino acid synthesis such as OxyR, KatG, and GltD altered important biofilm properties, including motility, biofilm maturation, or resistance to oxidative stress. Our study therefore revealed that S-nitrosylation constitutes a physiological basis underlying functions critical for E. coli adaptation to the biofilm environment.}, } @article {pmid33848818, year = {2021}, author = {Zhang, H and Li, X and An, Z and Liu, Z and Tang, C and Zhao, X}, title = {Treatment of polyacrylamide-polluted wastewater using a revolving algae biofilm reactor: Pollutant removal performance and microbial community characterization.}, journal = {Bioresource technology}, volume = {332}, number = {}, pages = {125132}, doi = {10.1016/j.biortech.2021.125132}, pmid = {33848818}, issn = {1873-2976}, mesh = {Acrylic Resins ; Biofilms ; Bioreactors ; *Environmental Pollutants ; *Microbiota ; Nitrogen/analysis ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Industries such as oil mining face challenges in the treatment of polyacrylamide (PAM)-containing wastewater produced during petroleum extraction. The feasibility of using revolving algae biofilm (RAB) reactors to treat PAM-contaminated wastewater for simultaneous removal of carbon and nitrogen was evaluated. The presence or absence of external nitrogen sources had a significant impact on the treatment effect of the RAB system. With the additional N source, the PAM, COD, TOC, and TN removal rates were 64.1 ± 2.0, 58 ± 1.5, 34.5 ± 1.5, and 85 ± 6.0%, respectively. High-throughput sequencing showed that the biofilms on RAB reactors contained a variety of bacteria, cyanobacteria, and green algae, degrading PAM through various mechanisms. The results of infrared spectroscopy analysis indicate that the product of these processes was carboxylic acid. Based on these results, it was concluded that RAB systems can be effectively applied to the treatment of polymer-containing wastewater.}, } @article {pmid33848132, year = {2021}, author = {Long, M and Long, X and Zheng, CW and Luo, YH and Zhou, C and Rittmann, BE}, title = {Para-Chlorophenol (4-CP) Removal by a Palladium-Coated Biofilm: Coupling Catalytic Dechlorination and Microbial Mineralization via Denitrification.}, journal = {Environmental science & technology}, volume = {55}, number = {9}, pages = {6309-6319}, doi = {10.1021/acs.est.0c08307}, pmid = {33848132}, issn = {1520-5851}, mesh = {Biofilms ; Bioreactors ; Catalysis ; *Chlorophenols ; Denitrification ; *Metal Nanoparticles ; Palladium ; }, abstract = {Rapid dechlorination and full mineralization of para-chlorophenol (4-CP), a toxic contaminant, are unfulfilled goals in water treatment. Means to achieve both goals stem from the novel concept of coupling catalysis by palladium nanoparticles (PdNPs) with biodegradation in a biofilm. Here, we demonstrate that a synergistic version of the hydrogen (H2)-based membrane biofilm reactor (MBfR) enabled simultaneous removals of 4-CP and cocontaminating nitrate. In situ generation of PdNPs within the MBfR biofilm led to rapid 4-CP reductive dechlorination, with >90% selectivity to more bioavailable cyclohexanone. Then, the biofilm mineralized the cyclohexanone by utilizing it as a supplementary electron donor to accelerate nitrate reduction. Long-term operation of the Pd-MBfR enriched the microbial community in cyclohexanone degraders within Clostridium, Chryseobacterium, and Brachymonas. In addition, the PdNP played an important role in accelerating nitrite reduction; while NO3[-] reduction to NO2[-] was entirely accomplished by bacteria, NO2[-] reduction to N2 was catalyzed by PdNPs and bacterial reductases. This study documents a promising option for efficient and complete remediation of halogenated organics and nitrate by the combined action of PdNP and bacterial catalysis.}, } @article {pmid33846447, year = {2021}, author = {Yassein, AS and Hassan, MM and Elamary, RB}, title = {Prevalence of lipase producer Aspergillus niger in nuts and anti-biofilm efficacy of its crude lipase against some human pathogenic bacteria.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {7981}, pmid = {33846447}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Aspergillus niger/*enzymology/genetics/isolation & purification/pathogenicity ; Bacteria/*drug effects/ultrastructure ; Base Sequence ; Biofilms/*drug effects ; Biosynthetic Pathways/genetics ; Humans ; Lipase/genetics/*pharmacology ; Microbial Sensitivity Tests ; Mycobiome/drug effects ; Nuts/*microbiology ; Ochratoxins/toxicity ; Phylogeny ; Virulence/drug effects ; }, abstract = {Nuts are the natural source of healthy lipids, proteins, and omega-3. They are susceptible to fungal and mycotoxins contamination because of their high nutritional value. Twenty-five species comprising 12 genera were isolated from 80 samples of dried fruits and nuts using the dilution plate method. Peanut recorded the highest level of contamination followed by coconut; almond and raisin were the lowest. Aspergillus was the most prevalent genus and A. niger, was the most dominant species. The morphological identification of the selected A. niger isolates as they were detected in high frequency of occurrence was confirmed by using 18SrRNA sequence. Ochratoxin biosynthesis gene Aopks was detected in the tested isolates. Lipase production by the selected A. niger isolates was determined with enzyme activity index (EAI) ranging from 2.02 to 3.28. A. niger-26 was the highest lipase producer with enzyme activity of 0.6 ± 0.1 U/ml by the trimetric method. Lip2 gene was also detected in the tested isolates. Finally, the antibacterial and antibiofilm efficiency of crude lipase against some human pathogens was monitored. Results exhibited great antibacterial efficacy with minimum bactericidal concentration (MBC) of 20 to 40 µl/100 µl against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Methicillin-resistant Staphylococcus aureus (MRSA). Interestingly, significant anti-biofilm efficacy with inhibition percentages of 95.3, 74.9, 77.1 and 93.6% was observed against the tested pathogens, respectively.}, } @article {pmid33846401, year = {2021}, author = {Provenzani, R and San-Martin-Galindo, P and Hassan, G and Legehar, A and Kallio, A and Xhaard, H and Fallarero, A and Yli-Kauhaluoma, J}, title = {Multisubstituted pyrimidines effectively inhibit bacterial growth and biofilm formation of Staphylococcus aureus.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {7931}, pmid = {33846401}, issn = {2045-2322}, mesh = {Anti-Infective Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*growth & development ; Biomass ; Cell Death/drug effects ; Cell Line ; Drug Design ; Humans ; Microbial Sensitivity Tests ; Plankton/drug effects ; Pyrimidines/chemical synthesis/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/*growth & development/*physiology ; Structure-Activity Relationship ; }, abstract = {Biofilms are multicellular communities of microorganisms that generally attach to surfaces in a self-produced matrix. Unlike planktonic cells, biofilms can withstand conventional antibiotics, causing significant challenges in the healthcare system. Currently, new chemical entities are urgently needed to develop novel anti-biofilm agents. In this study, we designed and synthesized a set of 2,4,5,6-tetrasubstituted pyrimidines and assessed their antibacterial activity against planktonic cells and biofilms formed by Staphylococcus aureus. Compounds 9e, 10d, and 10e displayed potent activity for inhibiting the onset of biofilm formation as well as for killing pre-formed biofilms of S. aureus ATCC 25923 and Newman strains, with half-maximal inhibitory concentration (IC50) values ranging from 11.6 to 62.0 µM. These pyrimidines, at 100 µM, not only decreased the number of viable bacteria within the pre-formed biofilm by 2-3 log10 but also reduced the amount of total biomass by 30-50%. Furthermore, these compounds were effective against planktonic cells with minimum inhibitory concentration (MIC) values lower than 60 µM for both staphylococcal strains. Compound 10d inhibited the growth of S. aureus ATCC 25923 in a concentration-dependent manner and displayed a bactericidal anti-staphylococcal activity. Taken together, our study highlights the value of multisubstituted pyrimidines to develop novel anti-biofilm agents.}, } @article {pmid33846117, year = {2021}, author = {Martínez-Méndez, R and Camacho-Hernández, DA and Sulvarán-Guel, E and Zamorano-Sánchez, D}, title = {A Trigger Phosphodiesterase Modulates the Global c-di-GMP Pool, Motility, and Biofilm Formation in Vibrio parahaemolyticus.}, journal = {Journal of bacteriology}, volume = {203}, number = {13}, pages = {e0004621}, pmid = {33846117}, issn = {1098-5530}, mesh = {Amino Acid Sequence ; Bacterial Proteins/chemistry/genetics ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/chemistry/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Phosphoric Diester Hydrolases/chemistry/genetics/*metabolism ; Second Messenger Systems ; Vibrio parahaemolyticus/genetics/*metabolism ; }, abstract = {Vibrio parahaemolyticus cells transit from free-swimming to surface adapted lifestyles, such as swarming colonies and three-dimensional biofilms. These transitions are regulated by sensory modules and regulatory networks that involve the second messenger cyclic diguanylate monophosphate (c-di-GMP). In this work, we show that a previously uncharacterized c-di-GMP phosphodiesterase (VP1881) from V. parahaemolyticus plays an important role in modulating the c-di-GMP pool. We found that the product of VP1881 promotes its own expression when the levels of c-di-GMP are low or when the phosphodiesterase (PDE) is catalytically inactive. This behavior has been observed in a class of c-di-GMP receptors called trigger phosphodiesterases, and hence we named the product of VP1881 TpdA, for trigger phosphodiesterase A. The absence of tpdA showed a negative effect on swimming motility while, its overexpression from an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible promoter showed a positive effect on both swimming and swarming motility and a negative effect on biofilm formation. Changes in TpdA abundance altered the expression of representative polar and lateral flagellar genes, as well as that of the biofilm-related gene cpsA. Our results also revealed that autoactivation of the native PtpdA promoter is sufficient to alter c-di-GMP signaling responses such as swarming and biofilm formation in V. parahaemolyticus, an observation that could have important implications in the dynamics of these social behaviors. IMPORTANCE c-di-GMP trigger phosphodiesterases (PDEs) could play a key role in controlling the heterogeneity of biofilm matrix composition, a property that endows characteristics that are potentially relevant for sustaining integrity and functionality of biofilms in a variety of natural environments. Trigger PDEs are not always easy to identify based on their sequence, and hence not many examples of these type of signaling proteins have been reported in the literature. Here, we report on the identification of a novel trigger PDE in V. parahaemolyticus and provide evidence suggesting that its autoactivation could play an important role in the progression of swarming motility and biofilm formation, multicellular behaviors that are important for the survival and dissemination of this environmental pathogen.}, } @article {pmid33844705, year = {2021}, author = {, }, title = {Correction: Enhanced biofilm and extracellular matrix production by chronic carriage versus acute isolates of Salmonella Typhi.}, journal = {PLoS pathogens}, volume = {17}, number = {4}, pages = {e1009512}, pmid = {33844705}, issn = {1553-7374}, abstract = {[This corrects the article DOI: 10.1371/journal.ppat.1009209.].}, } @article {pmid33842382, year = {2021}, author = {Hamada, M and Yamaguchi, T and Sato, A and Ono, D and Aoki, K and Kajiwara, C and Kimura, S and Maeda, T and Sasaki, M and Murakami, H and Ishii, Y and Tateda, K}, title = {Increased Incidence and Plasma-Biofilm Formation Ability of SCCmec Type IV Methicillin-Resistant Staphylococcus aureus (MRSA) Isolated From Patients With Bacteremia.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {602833}, pmid = {33842382}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents ; *Bacteremia ; Biofilms ; Chromosomes ; Humans ; Incidence ; Japan/epidemiology ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Plasma ; *Staphylococcal Infections/epidemiology ; }, abstract = {In Japan, Staphylococcal cassette chromosome mec (SCCmec) type IV methicillin-resistant Staphylococcus aureus (MRSA) is an increasingly prominent cause of bacteremia, but the virulence of most of these strains is unclear. We aimed to investigate the relationship between the molecular characteristics and the ability to form biofilms in the presence of blood plasma (plasma-biofilms) of MRSA strains isolated from bloodstream infections. In this study, the molecular characteristics and biofilms of MRSA strains isolated from blood cultures between 2015 and 2017 were analyzed by PCR-based assays, crystal violet staining, and confocal reflection microscopy methods. Among the 90 MRSA isolates, the detection rate of SCCmec type II clones decreased from 60.7 to 20.6%. The SCCmec type IV clone replaced the SCCmec type II clone as the dominant clone, with a detection rate increasing from 32.1 to 73.5%. The plasma-biofilm formation ability of the SCCmec type IV clone was higher than the SCCmec type II clone and even higher in strains harboring the cna or arcA genes. Plasma-biofilms, mainly composed of proteins, were formed quickly and strongly. Our study demonstrated the increased plasma-biofilm formation ability of SCCmec type IV strains.}, } @article {pmid33841557, year = {2021}, author = {Günther, F and Blessing, B and Dapunt, U and Mischnik, A and Mutters, NT}, title = {Ability of chlorhexidine, octenidine, polyhexanide and chloroxylenol to inhibit metabolism of biofilm-forming clinical multidrug-resistant organisms.}, journal = {Journal of infection prevention}, volume = {22}, number = {1}, pages = {12-18}, pmid = {33841557}, issn = {1757-1774}, abstract = {PURPOSE: This in vitro study was designed to determine if standard antiseptics used for skin and environmental surface cleansing can disrupt the metabolic activity (as a measure of viability) of multidrug-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus isolates within their native biofilms.

METHODS: Sixty clinical isolates of multidrug-resistant bacteria were selected for testing in different chlorhexidine gluconate, octenidine, polyhexanide and chloroxylenol concentrations. Metabolic inhibition of biofilm for each clinical isolate was analysed using a biofilm viability assay.

RESULTS: Chlorhexidine gluconate (mean = 83.8% ± 9.8%) and octenidine (mean = 84.5% ± 6.8%) showed the greatest efficacy against biofilms of the tested microorganisms, with the greatest efficacies against MRSA. The antiseptics demonstrated the least efficacy against biofilms of Pseudomonas aeruginosa.

CONCLUSION: Chlorhexidine gluconate and octenidine showed the greatest level of bacterial metabolic inhibition and were statistically equivalent. Polyhexanide was more effective than chloroxylenol, but both were inferior to chlorhexidine gluconate and octenidine against the tested organisms.}, } @article {pmid33841441, year = {2021}, author = {Fu, W and Liu, Y and Liu, F and Liu, C and Li, J and Niu, J and Han, P and Xu, D and Hou, J and Ma, Y and Feng, J and Li, Z and Mu, R and Yang, G}, title = {A Novel Autoantibody Induced by Bacterial Biofilm Conserved Components Aggravates Lupus Nephritis.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {656090}, pmid = {33841441}, issn = {1664-3224}, mesh = {Amino Acid Sequence ; Animals ; Antigens, Bacterial/chemistry/immunology ; Autoantibodies/blood/*immunology ; Autoantigens/immunology ; Bacteria/*immunology ; *Biofilms ; Biomarkers ; Disease Models, Animal ; Disease Progression ; Disease Susceptibility ; Enzyme-Linked Immunosorbent Assay ; Female ; Fluorescent Antibody Technique ; Humans ; Lupus Erythematosus, Systemic/*complications/*immunology/pathology ; Lupus Nephritis/blood/*etiology/*pathology ; Mice ; Mice, Transgenic ; Peptides/chemistry/immunology ; Terpenes/adverse effects ; }, abstract = {Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiple autoantibody production and often affects the kidneys, known as lupus nephritis. However, the mechanism underlying lupus nephritis development is unclear. Biofilms that protect bacteria from stress are ubiquitous in almost every environment. Here, we identified that a conserved peptide (HU1) derived from DNABII proteins, one of major bacterial biofilm components, was specifically recognized by sera from about 47% patients with SLE. Moreover, the serum anti-HU1 levels showed a significant positive correlation with lupus nephritis occurrence. Presence of antibodies against HU1 in pristane-induced mice aggravated lupus nephritis, although these antibodies also attenuated bacterial biofilm formation. We further identified that antibodies against HU1 cross-recognized protein disulfide isomerase (P4HB) located on the renal cell surface and inhibited the activities of this enzyme. Our findings reveal a novel mechanism underlying the development of lupus nephritis triggered by bacterial biofilms.}, } @article {pmid33841352, year = {2021}, author = {Evariste, L and Braylé, P and Mouchet, F and Silvestre, J and Gauthier, L and Flahaut, E and Pinelli, E and Barret, M}, title = {Graphene-Based Nanomaterials Modulate Internal Biofilm Interactions and Microbial Diversity.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {623853}, pmid = {33841352}, issn = {1664-302X}, abstract = {Graphene-based nanomaterials (GBMs), such as graphene oxide (GO) and reduced graphene oxide (rGO), possess unique properties triggering high expectations for the development of new technological applications and are forecasted to be produced at industrial-scale. This raises the question of potential adverse outcomes on living organisms and especially toward microorganisms constituting the basis of the trophic chain in ecosystems. However, investigations on GBMs toxicity were performed on various microorganisms using single species that are helpful to determine toxicity mechanisms but fail to predict the consequences of the observed effects at a larger organization scale. Thus, this study focuses on the ecotoxicological assessment of GO and rGO toward a biofilm composed of the diatom Nitzschia palea associated to a bacterial consortium. After 48 and 144 h of exposure to these GBMs at 0, 0.1, 1, and 10 mg.L[-1], their effects on the diatom physiology, the structure, and the metabolism of bacterial communities were measured through the use of flow cytometry, 16S amplicon sequencing, and Biolog ecoplates, respectively. The exposure to both of these GBMs stimulated the diatom growth. Besides, GO exerted strong bacterial growth inhibition as from 1 mg.L[-1], influenced the taxonomic composition of diatom-associated bacterial consortium, and increased transiently the bacterial activity related to carbon cycling, with weak toxicity toward the diatom. On the contrary, rGO was shown to exert a weaker toxicity toward the bacterial consortium, whereas it influenced more strongly the diatom physiology. When compared to the results from the literature using single species tests, our study suggests that diatoms benefited from diatom-bacteria interactions and that the biofilm was able to maintain or recover its carbon-related metabolic activities when exposed to GBMs.}, } @article {pmid33838816, year = {2021}, author = {Hemmingsen, LM and Giordani, B and Pettersen, AK and Vitali, B and Basnet, P and Škalko-Basnet, N}, title = {Liposomes-in-chitosan hydrogel boosts potential of chlorhexidine in biofilm eradication in vitro.}, journal = {Carbohydrate polymers}, volume = {262}, number = {}, pages = {117939}, doi = {10.1016/j.carbpol.2021.117939}, pmid = {33838816}, issn = {1879-1344}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Anti-Inflammatory Agents/chemistry/pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Chitosan/chemistry/*pharmacology ; Chlorhexidine/chemistry/*pharmacology ; Humans ; Hydrogels/chemistry/*pharmacology ; Lipopolysaccharides/metabolism ; Liposomes/chemistry/*pharmacology ; Macrophages/drug effects ; Mice ; Nitric Oxide/metabolism ; Pseudomonas aeruginosa/drug effects ; Skin Diseases, Bacterial/drug therapy ; Staphylococcus aureus/drug effects ; Wounds and Injuries/drug therapy ; }, abstract = {Successful treatment of skin infections requires eradication of biofilms found in up to 90 % of all chronic wounds, causing delayed healing and increased morbidity. We hypothesized that chitosan hydrogel boosts the activity of liposomally-associated membrane active antimicrobials (MAA) and could potentially improve bacterial and biofilm eradication. Therefore, liposomes (∼300 nm) bearing chlorhexidine (CHX; ∼50 μg/mg lipid) as a model MAA were incorporated into chitosan hydrogel. The novel CHX-liposomes-in-hydrogel formulation was optimized for skin therapy. It significantly inhibited the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced macrophage and almost completely reduced biofilm formation. Moreover, it reduced Staphylococcus aureus and Pseudomonas aeruginosa adherent bacterial cells in biofilm by 64.2-98.1 %. Chitosan hydrogel boosted the anti-inflammatory and antimicrobial properties of CHX.}, } @article {pmid33838179, year = {2021}, author = {Shivaee, A and Rajabi, S and Farahani, HE and Imani Fooladi, AA}, title = {Effect of sub-lethal doses of nisin on Staphylococcus aureus toxin production and biofilm formation.}, journal = {Toxicon : official journal of the International Society on Toxinology}, volume = {197}, number = {}, pages = {1-5}, doi = {10.1016/j.toxicon.2021.03.018}, pmid = {33838179}, issn = {1879-3150}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Enterotoxins ; Humans ; *Nisin/pharmacology ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Staphylococcus aureus is one of the commonest food-borne pathogens that can cause gastroenteritis owing to having several enterotoxins. Also, biofilm formation can complicate infections caused by this microorganism. Nisin is a safe food bio preservative which is usually used as an agent to prevent pathogen growth; however, it is important to identify the exact impact of nisin on the growth of S. aureus and to determine the suitable concentration needed for elimination of this pathogen in food. In this study, after MIC determination of nisin against S. aureus ATCC 29213, this strain was treated with sub-MIC (1/2) of nisin (4 μg/ml) and transcript levels of toxin-encoding (hla, SEA, SEB, and SED) and biofilm-associated (fnb, ebpS, eno, and icaA) genes were determined using Quantitative Real-time PCR at 2, 8, and 24 h post exposure. All toxin genes were down-regulated following exposure to sub-MIC of nisin, whereas biofilm-associated genes were up-regulated. The expression levels of fnb and icaA in S. aureus were highest after 8 h (4.5-fold and 6.8-fold increase, respectively), while the expression levels of eno and ebpS genes were highest after 2 h (3.3 and 4.5-fold increase, respectively). According to these results, although transcriptional levels of toxin genes were reduced, sub-MIC concentrations of nisin could trigger the expression of biofilm-associated genes in S. aureus. This can further lead to bacteriocin tolerance such that even its higher concentrations cannot kill bacterial cells after exposure to sub-lethal doses. Therefore, it is pivotal to add appropriate concentrations of nisin to food products for preservation purposes.}, } @article {pmid33837872, year = {2021}, author = {Chen, M and Yu, N and Chen, Y and Tong, Q and Guo, Y}, title = {Anaerobic semi-fixed bed biofilm reactor (An-SFB-BR) for treatment of high concentration p-nitrophenol wastewater under shock loading conditions.}, journal = {Biodegradation}, volume = {32}, number = {4}, pages = {377-388}, pmid = {33837872}, issn = {1572-9729}, support = {2019YFG0324//Science and Technology Program of Sichuan/ ; }, mesh = {Anaerobiosis ; Biodegradation, Environmental ; Biofilms ; *Bioreactors ; Nitrophenols ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {P-nitrophenol (PNP or 4-NP) has been widely used as a biorefractory raw material in chemical industry, whereas been highly concerned for its characteristics of mutagenic/carcinogenic activity and food chain bioaccumulation. In this study, an anaerobic semi-fixed bed biofilm reactor (An-SFB-BR) was constructed and used to treat PNP wastewater which discharged from chemical industries. Experimental results revealed that the An-SFB-BR was successfully cultivated with the gradually increasing of influent PNP from 0 to 540 mg/L (gradually increased 10 mg/L every time in stage II and 30-50 mg/L for stage III), with the observation of an average removal efficiency of 98% for PNP and 80% for chemical oxygen demand (COD), also a biogas production and biogas production rate of 2.1 L/(L·d) and 0.57 m[3]/kg-COD, respectively. Finally, the conversion rate of P-aminophenol (PAP), the primary intermediate of PNP reached 80% after An-SFB-BR biodegradation. A relatively stable pH was maintained throughout the entire process, and insignificant VFA accumulation. The reactor exhibited a strong toxic shock resistance, and 16S rRNA sequencing results demonstrated that the dominant microbial community changed slightly with the gradually increasing of PNP concentration, which guaranteed the PNP removal efficiency.}, } @article {pmid33837303, year = {2021}, author = {Etayash, H and Haney, EF and Hancock, REW}, title = {Assessing biofilm inhibition and immunomodulatory activity of small amounts of synthetic host defense peptides synthesized using SPOT-array technology.}, journal = {Nature protocols}, volume = {16}, number = {4}, pages = {1850-1870}, pmid = {33837303}, issn = {1750-2799}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Antimicrobial Cationic Peptides/*chemical synthesis/pharmacology ; Biofilms/*drug effects ; Cell Death/drug effects ; Humans ; Immunologic Factors/*pharmacology ; Protein Array Analysis/*methods ; }, abstract = {Peptides are promising drug candidates because of their diversity, biocompatibility and spectrum of activities. Here, we describe a protocol for high-throughput screening of SPOT-peptide arrays to assess the antibiofilm, antimicrobial and immunomodulatory activities of synthetic peptides. It is a Protocol Extension of our previous Nature Protocols article, which describes the synthesis of SPOT-peptide arrays and assays for screening antimicrobial activity. This latest protocol allows the simultaneous assessment of hundreds of synthetic host defense peptides to define their overall activity profiles and identify candidate sequences that are suitable for further characterization and development as anti-infectives. When coupled with the SPOT-array technology for peptide synthesis, the described procedures are rapid, inexpensive and straightforward for peptide library screening. The protocols can be implemented in most microbiology or immunology research laboratories without the need for specialists. The time to complete each step ranges between 1 and 4 h with overnight pauses, and datasets related to the antibiofilm and immunomodulatory activities of a large set of peptide sequences can be generated in a few days.}, } @article {pmid33836738, year = {2021}, author = {Brill, FHH and Hambach, J and Utpatel, C and Mogrovejo, DC and Gabriel, H and Klock, JH and Steinmann, J and Arndt, A}, title = {Biofilm reduction potential of 0.02% polyhexanide irrigation solution in several types of urethral catheters.}, journal = {BMC urology}, volume = {21}, number = {1}, pages = {58}, pmid = {33836738}, issn = {1471-2490}, mesh = {Biguanides/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Disinfectants/administration & dosage/*pharmacology ; Equipment Contamination/*prevention & control ; Humans ; Therapeutic Irrigation ; Urinary Catheters/*microbiology ; }, abstract = {BACKGROUND: Long-term use of urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage. Microbial biofilms are a common cause of catheter blockage, reducing their lifetime and significantly increasing morbidity of UTIs. A 0.02% polyhexanide irrigation solution developed for routine mechanical rinsing shows potential for bacterial decolonization of urethral catheters and has the potential to reduce or prevent biofilm formation.

METHODS: Using an in vitro assay with standard market-leading types of catheters artificially contaminated with clinically relevant bacteria, assays were carried out to evaluate the biofilm reduction and prevention potential of a 0.02% polyhexanide solution versus no intervention (standard approach) and irrigation with saline solution (NaCl 0.9%). The efficiency of decolonization was measured through microbial plate count and membrane filtration.

RESULTS: Irrigation using a 0.02% polyhexanide solution is suitable for the decolonization of a variety of transurethral catheters. The effect observed is significant compared to irrigation with 0.9% saline solution (p = 0.002) or no treatment (p = 0.011). No significant difference was found between irrigation with 0.9% saline solution and no treatment (p = 0.74).

CONCLUSIONS: A 0.02% polyhexanide solution is able to reduce bacterial biofilm from catheters artificially contaminated with clinically relevant bacteria in vitro. The data shows a reduction of the viability of thick bacterial biofilms in a variety of commercially available urinary catheters made from silicone, latex-free silicone, hydrogel-coated silicone and PVC. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.}, } @article {pmid33836506, year = {2021}, author = {Li, K and Liu, Z and Liu, X and Wang, L and Zhao, J and Zhang, X and Kong, Y and Chen, M}, title = {An anti-biofilm material: polysaccharides prevent the precipitation reaction of silver ions and chloride ions and lead to the synthesis of nano silver chloride.}, journal = {Nanotechnology}, volume = {32}, number = {31}, pages = {}, doi = {10.1088/1361-6528/abf68e}, pmid = {33836506}, issn = {1361-6528}, mesh = {A549 Cells ; Biofilms/drug effects ; Cell Line ; Chemical Precipitation ; Chlorides/*chemistry ; Humans ; Nanoparticles ; Polysaccharides/*chemistry ; Silver/*chemistry ; Silver Compounds/*chemistry ; X-Ray Diffraction ; }, abstract = {The formation of biofilm is one of the causes of bacterial pathogenicity and drug resistance. Recent studies have reported a variety of anti-biofilm materials and achieved good results. However, it is still very important to develop some materials with wider application scenarios or higher biofilm resistance. In this study, a new method to rapidly synthesize nano silver chloride with anti-biofilm activity is proposed. It is a generalizable method in which bacterial extracellular polysaccharides are used to adsorb silver ions, thereby inhibiting the formation of white large-size silver chloride precipitates, and then ultraviolet light is used to induce the synthesis of small-sized nano silver chloride. A variety of polysaccharides can be utilized in the synthesis of nano silver chloride particles. The generated complex was characterized by XRD, UV-vis, EDX, FTIR and TEM methods. Further, the novel complex was found to show highly effective anti-biofilm and bactericidal activity within the biosafety concentration. In view of the high stability of nano sliver chloride, we propose that the novel nano material has the potential as a long-term antibacterial material.}, } @article {pmid33836275, year = {2021}, author = {Pourhajibagher, M and Rahimi-Esboei, B and Ahmadi, H and Bahador, A}, title = {The anti-biofilm capability of nano-emodin-mediated sonodynamic therapy on multi-species biofilms produced by burn wound bacterial strains.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {34}, number = {}, pages = {102288}, doi = {10.1016/j.pdpdt.2021.102288}, pmid = {33836275}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; *Burns/therapy ; *Emodin ; Humans ; *Photochemotherapy/methods ; Photosensitizing Agents ; }, abstract = {BACKGROUND: Management of burn wound infections (BWIs) is difficult due to the emergence of multidrug-resistant microorganisms. This study aimed to explore the anti-biofilm efficacy of sonodynamic therapy (SDT) using nano-emodin (N-EMO) against multi-species bacterial biofilms containing Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii.

METHODS: Following synthesis and confirmation of N-EMO as a sonosensitizer, the anti-biofilm efficacy of SDT against multi-species bacterial biofilms was determined using minimum inhibitory concentrations (MIC), minimum biofilm inhibitory concentration (MBIC), and minimal biofilm eradication concentration (MBEC) of N-EMO. The reduction of multi-species bacterial biofilms was then evaluated following the treatments using Log reduction and crystal violet (CV) assays. In addition, the expression profiling of abaI, agrA, and lasI genes using SDT with sub-MIC, sub-MBIC, and sub-MBEC of N-EMO was assessed.

RESULTS: Successful synthesis of N-EMO was confirmed through several characterization tests. As the results demonstrated, the MIC value of N-EMO for the multi-species bacterial suspension was 0.15 × 10[-4] g/L, as well as, the MBEC value of N-EMO was 2.5 × 10[-4] g/L, approximately 4-fold higher than that of MBIC (0.62 × 10[-4] g/L). According to the CV assay, there were 57.8 %, 71.0 %, and 81.5 % reduction in the biofilm of multi-species bacterial growth following SDT using 1/128 MBEC, 1/16 MBIC, and 1/2 MIC of N-EMO, respectively. Log reductions analysis demonstrated that 1/2 MIC of N-EMO was more potent in inhibiting the biofilm growth of multi-species test bacteria by 5.725 ± 0.12 (99.9993 %). In this study, N-EMO-mediated SDT could obviously downregulate the gene expression of virulence factors (P < 0.05). The gene expression of lasI, agrA, and abaI were downregulated about 2.5-, 3.6-, and 5.5-fold; and 3.0-, 5.2-, and 7.4-fold following SDT with sub-MBIC and sub-MBEC of N-EMO, respectively.

CONCLUSION: These results highlight the potential of N-EMO-mediated SDT in inhibition of biofilm formation, degradation of formed biofilms, and reduction of virulence factor associated with biofilms of multi-species bacterial biofilms in BWIs.}, } @article {pmid33835090, year = {2021}, author = {Manasherob, R and Mooney, JA and Lowenberg, DW and Bollyky, PL and Amanatullah, DF}, title = {Tolerant Small-colony Variants Form Prior to Resistance Within a Staphylococcus aureus Biofilm Based on Antibiotic Selective Pressure.}, journal = {Clinical orthopaedics and related research}, volume = {479}, number = {7}, pages = {1471-1481}, pmid = {33835090}, issn = {1528-1132}, support = {KL2 TR003143/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial/*drug effects ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/*drug therapy/microbiology ; Rifampin/pharmacology ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: The treatment of periprosthetic joint infection (PJI) is focused on the surgical or chemical removal of biofilm. Antibiotics in isolation are typically ineffective against PJI. Bacteria survive after antibiotic administration because of antibiotic tolerance, resistance, and persistence that arise in the resident bacteria of a biofilm. Small-colony variants are typically slow-growing bacterial subpopulations that arise after antibiotic exposure and are associated with persistent and chronic infections such as PJI. The role of biofilm-mediated antibiotic tolerance in the emergence of antibiotic resistance remains poorly defined experimentally.

QUESTIONS/PURPOSES: We asked: (1) Does prior antibiotic exposure affect how Staphylococcus aureus survives within a developing biofilm when exposed to an antibiotic that penetrates biofilm, like rifampicin? (2) Does exposure to an antibiotic with poor biofilm penetration, such as vancomycin, affect how S. aureus survives within a developing biofilm? (3) Do small-colony variants emerge from antibiotic-tolerant or -resistant bacteria in a S. aureus biofilm?

METHODS: We used a porous membrane as an in vitro implant model to grow luminescent S. aureus biofilms and simultaneously track microcolony expansion. We evaluated the impact of tolerance on the development of resistance by comparing rifampicin (an antibiotic that penetrates S. aureus biofilm) with vancomycin (an antibiotic that penetrates biofilm poorly). We performed viability counting after membrane dissociation to discriminate among tolerant, resistant, and persistent bacteria. Biofilm quantification and small-colony morphologies were confirmed using scanning electron microscopy. Because of experimental variability induced by the starting bacterial inoculum, relative changes were compared since absolute values may not have been statistically comparable.

RESULTS: Antibiotic-naïve S. aureus placed under the selective pressure of rifampicin initially survived within an emerging biofilm by using tolerance given that biofilm resident cell viability revealed 1.0 x 108 CFU, of which 7.5 x 106 CFU were attributed to the emergence of resistance and 9.3 x 107 CFU of which were attributed to the development of tolerance. Previous exposure of S. aureus to rifampicin obviated tolerance-mediate survival when rifampicin resistance was present, since the number of viable biofilm resident cells (9.5 x 109 CFU) nearly equaled the number of rifampicin-resistant bacteria (1.1 x 1010 CFU). Bacteria exposed to an antibiotic with poor biofilm penetration, like vancomycin, survive within an emerging biofilm by using tolerance as well because the biofilm resident cell viability for vancomycin-naïve (1.6 x 1010 CFU) and vancomycin-resistant (1.0 x 1010 CFU) S. aureus could not be accounted for by emergence of resistance. Adding rifampicin to vancomycin resulted in a nearly 500-fold reduction in vancomycin-tolerant bacteria from 1.5 x 1010 CFU to 3.3 x 107 CFU. Small-colony variant S. aureus emerged within the tolerant bacterial population within 24 hours of biofilm-penetrating antibiotic administration. Scanning electron microscopy before membrane dissociation confirmed the presence of small, uniform cells with biofilm-related microstructures when unexposed to rifampicin as well as large, misshapen, lysed cells with a small-colony variant morphology [29, 41, 42, 63] and a lack of biofilm-related microstructures when exposed to rifampicin. This visually confirmed the rapid emergence of small-colony variants within the sessile niche of a developing biofilm when exposed to an antibiotic that exerted selective pressure.

CONCLUSION: Tolerance explains why surgical and nonsurgical modalities that rely on antibiotics to "treat" residual microscopic biofilm may fail over time. The differential emergence of resistance based on biofilm penetration may explain why some suppressive antibiotic therapies that do not penetrate biofilm well may rely on bacterial control while limiting the emergence of resistance. However, this strategy fails to address the tolerant bacterial niche that harbors persistent bacteria with a small-colony variant morphology.

CLINICAL RELEVANCE: Our work establishes biofilm-mediated antibiotic tolerance as a neglected feature of bacterial communities that prevents the effective treatment of PJI.}, } @article {pmid33834674, year = {2021}, author = {Li, XW and Wang, YF and Jiang, WT and Zhang, LL}, title = {[Effects of antimicrobial peptide GH12 on the morphology and composition of cariogenic three-species biofilm].}, journal = {Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology}, volume = {39}, number = {2}, pages = {188-194}, pmid = {33834674}, issn = {2618-0456}, mesh = {Biofilms ; *Dental Caries ; Humans ; In Situ Hybridization, Fluorescence ; Pore Forming Cytotoxic Proteins ; Streptococcus mutans ; }, abstract = {OBJECTIVES: To evaluate the effects of antimicrobial peptide GH12 designed de novo on the structure, morphology, and composition of a cariogenic three-species biofilm.

METHODS: The cariogenic three-species biofilm consis-ted of the cariogenic Streptococcus mutans (S. mutans) and commensal bacteria Streptococcus sanguinis (S. sanguinis) and Streptococcus gordonii (S. gordonii). The biofilm was treated using GH12 (2, 4, and 8 mg·L[-1]), and untreated biofilm was used as the control. Changes in the morphology and structure of the three-species biofilm were evaluated through crystal violet staining, scanning electron microscopy (SEM), and fluorescent in situ hybridization (FISH). Moreover, S. mutans in the biofilm was selectively cultured, and its colony-forming units were counted.

RESULTS: The biomass and density of the cariogenic three-species biofilm treated with GH12 decreased compared with those of the control. The number of S. mutans decreased gradually and eventually became undetectable, whereas the number of S. gordonii and S. sanguinis increased and became predominant in the biofilm.

CONCLUSIONS: GH12 can reduce the number of S. mutans within the cariogenic three-species biofilm, destroys its integrity, and consequently makes the biofilm easy to remove.}, } @article {pmid33833739, year = {2021}, author = {Vijay, K and Kiran, GS and Divya, S and Thangavel, K and Thangavelu, S and Dhandapani, R and Selvin, J}, title = {Fatty Acid Methyl Esters From the Coral-Associated Bacterium Pseudomonas aeruginosa Inhibit Virulence and Biofilm Phenotypes in Multidrug Resistant Staphylococcus aureus: An in vitro Approach.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {631853}, pmid = {33833739}, issn = {1664-302X}, abstract = {In an attempt to study the antibacterial, antivirulence and antibiofilm potentials of bacteria residing the tissue and surface mucus layers of the pristine corals, we screened a total of 43 distinct bacterial morphotypes from the coral Favites sp. Among the isolates, Pseudomonas aeruginosa strain CBMGL12 with showed antibacterial, antivirulence and antibiofilm activity against multidrug resistant pathogenic strains of Staphylococcus aureus (reference strain: MTCC96; community-acquired methicillin resistant strain: CA-MRSA). Extracellular products (ECP) from the coral-associated bacterium P. aeruginosa were solvent extracted, fractionated by chromatographic techniques such as silica column and HPLC-UV with concomitant bioassays guiding the fractionation of metabolites. Identification of bioactive chemical moieties was performed by FT-IR analysis, GC-MS/MS equipped with NIST library, [1]H and [13]C NMR spectral studies. We report the differential production of extracellular and cell-associated virulence and biofilm phenotypes in multi-drug resistant strains of S. aureus, post-treatment with the ECP containing aromatic fatty acid methyl esters (FAME) such as methyl benzoate and methyl phenyl acetate produced by a coral-associated bacterium. In conclusion, this study has identified antibacterial, antibiofilm and antivirulent FAME from the coral-associated P. aeruginosa for its ability to attenuate virulence and biofilms phenotypes in multi-drug resistant pathogenic strains of S. aureus.}, } @article {pmid33831774, year = {2021}, author = {D'Ugo, E and Bertuccini, L and Spadaro, F and Giuseppetti, R and Iosi, F and Santavenere, F and Giuliani, F and Gricia, M and Rodomonte, A and Lovecchio, N and Mukherjee, A and Bucci, P and Bruno, M and Stellacci, E and Bernardo, A and Magurano, F}, title = {Electrogenic and hydrocarbonoclastic biofilm at the oil-water interface as microbial responses to oil spill.}, journal = {Water research}, volume = {197}, number = {}, pages = {117092}, doi = {10.1016/j.watres.2021.117092}, pmid = {33831774}, issn = {1879-2448}, mesh = {Biofilms ; Ecosystem ; Humans ; Hydrocarbons ; *Petroleum Pollution/analysis ; Water ; }, abstract = {The oil-water interface formed during an oil spill represents a challenging environment for pelagic communities living in aquatic ecosystems. At this anoxic barrier, we report the formation of a microbial hydrocarbonoclastic biofilm capable of electron transfer along the water column. This biofilm generated a membrane of surface-active compounds that allowed the spontaneous separation of electrical charges, causing the establishment of an anodic and a cathodic region and, as a result, the spontaneous creation of a liquid microbial fuel cell. Such floating biofilm was connected to the water column underneath by floating filaments that could contribute to oxygen reduction at distance. The filaments revealed an unusual lipid content induced by anoxic conditions, with prominent ultrastructural features similar to myelin found in oligodendrocytes of the vertebrate nervous system. Furthermore, these filaments showed an interesting cross-reactivity towards different epitopes of the myelin basic protein (MBP) and Claudin 11 (O4) of human oligodendrocytes. The presence of a network of filaments similar to myelin suggests the probable existence of evolutionary connections between very distant organisms. Collectively these results suggest a possible mechanism for how lake microbial communities can adapt to oil spills while offering an interesting starting point for technological developments of liquid microbial fuel cells related to the study of hydrocarbon-water interfaces. The data that support the findings of this study are openly available in figshare at https://figshare.com/s/72bc73ae14011dc7920d.}, } @article {pmid33829140, year = {2021}, author = {Olubisose, ET and Ajayi, A and Adeleye, AI and Smith, SI}, title = {Molecular and phenotypic characterization of efflux pump and biofilm in multi-drug resistant non-typhoidal Salmonella Serovars isolated from food animals and handlers in Lagos Nigeria.}, journal = {One health outlook}, volume = {3}, number = {}, pages = {2}, pmid = {33829140}, issn = {2524-4655}, abstract = {BACKGROUND: Multidrug resistance efflux pumps and biofilm formation are mechanisms by which bacteria can evade the actions of many antimicrobials. Antibiotic resistant non-typhoidal Salmonella serovars have become wide spread causing infections that result in high morbidity and mortality globally. The aim of this study was to evaluate the efflux pump activity and biofilm forming capability of multidrug resistant non-typhoidal Salmonella (NTS) serovars isolated from food handlers and animals (cattle, chicken and sheep) in Lagos.

METHODS: Forty eight NTS serovars were subjected to antibiotic susceptibility testing by the disc diffusion method and phenotypic characterization of biofilm formation was done by tissue culture plate method. Phenotypic evaluation of efflux pump activity was done by the ethidium bromide cartwheel method and genes encoding biofilm formation and efflux pump activity were determined by PCR.

RESULTS: All 48 Salmonella isolates displayed resistance to one or more classes of test antibiotics with 100% resistance to amoxicillin-clavulanic acid. Phenotypically, 28 (58.3%) of the isolates exhibited efflux pump activity. However, genotypically, 7 (14.6%) of the isolates harboured acrA, acrB and tolC, 8 (16.7%) harboured acrA, acrD and tolC while 33 (68.8%) possessed acrA, acrB, acrD and tolC. All (100%) the isolates phenotypically had the ability to form biofilm with 23 (47.9%), 24 (50.0%), 1 (2.1%) categorized as strong (SBF), moderate (MBF) and weak (WBF) biofilm formers respectively but csgA gene was detected in only 23 (47.9%) of them. Antibiotic resistance frequency was significant (p < 0.05) in SBF and MBF and efflux pump activity was detected in 6, 21, and 1 SBF, MBF and WBF respectively.

CONCLUSION: These data suggest that Salmonella serovars isolated from different food animals and humans possess active efflux pumps and biofilm forming potential which has an interplay in antibiotic resistance. There is need for prudent use of antibiotics in veterinary medicine and scrupulous hygiene practice to prevent the transmission of multidrug resistant Salmonella species within the food chain.}, } @article {pmid33829001, year = {2021}, author = {Marincola, G and Jaschkowitz, G and Kieninger, AK and Wencker, FDR and Feßler, AT and Schwarz, S and Ziebuhr, W}, title = {Plasmid-Chromosome Crosstalk in Staphylococcus aureus: A Horizontally Acquired Transcription Regulator Controls Polysaccharide Intercellular Adhesin-Mediated Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {660702}, pmid = {33829001}, issn = {2235-2988}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms ; Cattle ; Chromosomes/metabolism ; Gene Expression Regulation, Bacterial ; *Methicillin-Resistant Staphylococcus aureus ; Plasmids ; Polysaccharides, Bacterial ; *Staphylococcal Infections ; Staphylococcus aureus/genetics ; Staphylococcus epidermidis/genetics ; }, abstract = {Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) of clonal complex CC398 typically carry various antimicrobial resistance genes, many of them located on plasmids. In the bovine LA-MRSA isolate Rd11, we previously identified plasmid pAFS11 in which resistance genes are co-localized with a novel ica-like gene cluster, harboring genes required for polysaccharide intercellular adhesin (PIA)-mediated biofilm formation. The ica genes on pAFS11 were acquired in addition to a pre-existing ica locus on the S. aureus Rd11 chromosomal DNA. Both loci consist of an icaADBC operon and icaR, encoding a corresponding icaADBC repressor. Despite carrying two biofilm gene copies, strain Rd11 did not produce PIA and transformation of pAFS11 into another S. aureus strain even slightly diminished PIA-mediated biofilm formation. By focusing on the molecular background of the biofilm-negative phenotype of pAFS11-carrying S. aureus, we identified the pAFS11-borne ica locus copy as functionally fully active. However, transcription of both plasmid- and core genome-derived icaADBC operons were efficiently suppressed involving IcaR. Surprisingly, although being different on the amino acid sequence level, the two IcaR repressor proteins are mutually replaceable and are able to interact with the icaA promoter region of the other copy. We speculate that this regulatory crosstalk causes the biofilm-negative phenotype in S. aureus Rd11. The data shed light on an unexpected regulatory interplay between pre-existing and newly acquired DNA traits in S. aureus. This also raises interesting general questions regarding functional consequences of gene transfer events and their putative implications for the adaptation and evolution of bacterial pathogens.}, } @article {pmid33827540, year = {2021}, author = {Tanaka, T and Yahata, Y and Handa, K and Venkataiah, SV and Njuguna, MM and Kanehira, M and Hasegawa, T and Noiri, Y and Saito, M}, title = {An experimental intraradicular biofilm model in the pig for evaluating irrigation techniques.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {177}, pmid = {33827540}, issn = {1472-6831}, mesh = {Animals ; Biofilms ; *Dental Pulp Cavity ; Male ; RNA, Ribosomal, 16S/genetics ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Swine ; Therapeutic Irrigation ; }, abstract = {BACKGROUND: We established an in vivo intraradicular biofilm model of apical periodontitis in pigs in which we compared the efficacy of different irrigant activation techniques for biofilm removal.

METHODS: Twenty roots from the deciduous mandibular second premolar of 5 male pigs were used. After pulpectomy, canals were left open for 2 weeks and then sealed for 4 weeks to enable the development of an intracanal biofilm. The intraradicular biofilms was evaluated using SEM and bacterial 16S rRNA gene-sequencing. To investigate the efficacy of biofilm removal, root canal irrigations were performed using conventional needle, passive ultrasonic, subsonic, or laser-activated irrigation. Real-time PCR was conducted to quantitate the remaining biofilm components. Statistical analysis was performed using ANOVA followed by a Tukey kramer post-hoc test with α = 0.05.

RESULTS: The pulp exposure model was effective in inducing apical periodontitis and SEM analysis revealed a multi-layer biofilm formation inside the root canal. 16S rRNA sequence analysis identified Firmicutes, Bacteroidetes, and Fusobacteria as the predominant bacterial phyla components, which is similar to the microbiome profile seen in humans. None of the tested irrigation techniques completely eradicated the biofilm components from the root canal, but the subsonic and laser-activated irrigation methods produced the lowest bacterial counts (p < 0.05).

CONCLUSIONS: An experimental intraradicular biofilm model has been successfully established in pigs. Within the limitations of the study, subsonic or laser-activated irrigation demonstrated the best biofilm removal results in the pig system.}, } @article {pmid33826367, year = {2021}, author = {Lingo, DE and Shukla, N and Osmani, AH and Osmani, SA}, title = {Aspergillus nidulans biofilm formation modifies cellular architecture and enables light-activated autophagy.}, journal = {Molecular biology of the cell}, volume = {32}, number = {12}, pages = {1181-1192}, pmid = {33826367}, issn = {1939-4586}, mesh = {Aspergillus nidulans/physiology/*ultrastructure ; *Autophagy ; *Biofilms ; Endocytosis ; Endoplasmic Reticulum/metabolism/*physiology ; Exocytosis ; Fungal Proteins/metabolism ; Golgi Apparatus/metabolism/physiology ; *Light ; Microtubules/metabolism ; Transcription Factors/metabolism ; }, abstract = {After growing on surfaces, including those of medical and industrial importance, fungal biofilms self-generate internal microenvironments. We previously reported that gaseous microenvironments around founder Aspergillus nidulans cells change during biofilm formation causing microtubules to disassemble under control of the hypoxic transcription factor SrbA. Here we investigate if biofilm formation might also promote changes to structures involved in exocytosis and endocytosis. During biofilm formation, the endoplasmic reticulum (ER) remained intact but ER exit sites and the Golgi apparatus were modified as were endocytic actin patches. The biofilm-driven changes required the SrbA hypoxic transcription factor and could be triggered by nitric oxide, further implicating gaseous regulation of biofilm cellular architecture. By tracking green fluorescent protein (GFP)-Atg8 dynamics, biofilm founder cells were also observed to undergo autophagy. Most notably, biofilm cells that had undergone autophagy were triggered into further autophagy by spinning disk confocal light. Our findings indicate that fungal biofilm formation modifies the secretory and endocytic apparatus and show that biofilm cells can also undergo autophagy that is reactivated by light. The findings provide new insights into the changes occurring in fungal biofilm cell biology that potentially impact their unique characteristics, including antifungal drug resistance.}, } @article {pmid33825680, year = {2021}, author = {Mancera, E and Nocedal, I and Hammel, S and Gulati, M and Mitchell, KF and Andes, DR and Nobile, CJ and Butler, G and Johnson, AD}, title = {Evolution of the complex transcription network controlling biofilm formation in Candida species.}, journal = {eLife}, volume = {10}, number = {}, pages = {}, pmid = {33825680}, issn = {2050-084X}, support = {CB-2016-01 282511//CONACyT/ ; LT000484/2012-L//Human Frontier Science Program/ ; R35GM124594//National Institute of Health/ ; 209077/Z/17/Z/WT_/Wellcome Trust/United Kingdom ; LT000484/2012-L//Human Frontiers Science Program/ ; Ro1AI049187//National Institute of Health/ ; R01 AI073289/AI/NIAID NIH HHS/United States ; R21AI125801//National Institute of Health/ ; R35 GM124594/GM/NIGMS NIH HHS/United States ; Ro1AI083311//National Institute of Health/ ; Ro1AI073289//National Institute of Health/ ; CB-2016-01 282511//Consejo Nacional de Ciencia y Tecnología/ ; }, mesh = {*Biofilms ; Candida albicans/genetics/*physiology ; *Evolution, Molecular ; Gene Regulatory Networks/*physiology ; }, abstract = {We examine how a complex transcription network composed of seven 'master' regulators and hundreds of target genes evolved over a span of approximately 70 million years. The network controls biofilm formation in several Candida species, a group of fungi that are present in humans both as constituents of the microbiota and as opportunistic pathogens. Using a variety of approaches, we observed two major types of changes that have occurred in the biofilm network since the four extant species we examined last shared a common ancestor. Master regulator 'substitutions' occurred over relatively long evolutionary times, resulting in different species having overlapping but different sets of master regulators of biofilm formation. Second, massive changes in the connections between the master regulators and their target genes occurred over much shorter timescales. We believe this analysis is the first detailed, empirical description of how a complex transcription network has evolved.}, } @article {pmid33824875, year = {2021}, author = {Gong, J and Hu, D and He, J and Zou, L and Chen, Z and Li, M}, title = {Effect of LongZhang Gargle on Dual-Species Biofilm of Candida albicans and Streptococcus mutans.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {6654793}, pmid = {33824875}, issn = {2314-6141}, mesh = {Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Drugs, Chinese Herbal/*pharmacology ; Humans ; Mouthwashes/*pharmacology ; Streptococcus mutans/*physiology ; }, abstract = {Bioactive natural products have become a hot spot for oral disease treatments. At the present study, LongZhang Gargle was investigated for its effects on single-species biofilms of Candida albicans and dual-species biofilms of Candida albicans and Streptococcus mutans. Two different models of single and dual-species biofilms were grown in YNBB medium under appropriate conditions. Biofilm biomass, biofilm architecture, and cell activity in biofilms were assessed using Crystal Violet Staining, MTT, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Significant reductions of biofilm biomass and fungus activity were obtained when treated with LongZhang Gargle at 2% (P < 0.05), 4% (P < 0.05), and 8% (P < 0.05) in single-species biofilms of C. albicans, and at 4% (P < 0.05) and 8% (P < 0.05) in double-species biofilms. Suppression of density, thickness, and the proportion of hyphae and fungal spores were obtained under SEM and CLSM. In conclusion, LongZhang Gargle affects single and dual-species biofilms by inhibiting biofilm biomass, cell activity, and formation of hyphae, but it does not affect the production of Extracellular polysaccharides (EPS). We speculate that LongZhang Gargle would be a promising natural drug, which can be used in treatment against C. albicans and S. mutans in oral diseases.}, } @article {pmid33824496, year = {2021}, author = {Arnaouteli, S and Bamford, NC and Stanley-Wall, NR and Kovács, ÁT}, title = {Bacillus subtilis biofilm formation and social interactions.}, journal = {Nature reviews. Microbiology}, volume = {19}, number = {9}, pages = {600-614}, pmid = {33824496}, issn = {1740-1534}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/*physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/physiology ; Microbial Interactions/*physiology ; }, abstract = {Biofilm formation is a process in which microbial cells aggregate to form collectives that are embedded in a self-produced extracellular matrix. Bacillus subtilis is a Gram-positive bacterium that is used to dissect the mechanisms controlling matrix production and the subsequent transition from a motile planktonic cell state to a sessile biofilm state. The collective nature of life in a biofilm allows emergent properties to manifest, and B. subtilis biofilms are linked with novel industrial uses as well as probiotic and biocontrol processes. In this Review, we outline the molecular details of the biofilm matrix and the regulatory pathways and external factors that control its production. We explore the beneficial outcomes associated with biofilms. Finally, we highlight major advances in our understanding of concepts of microbial evolution and community behaviour that have resulted from studies of the innate heterogeneity of biofilms.}, } @article {pmid33824212, year = {2021}, author = {Guo, S and Vance, TDR and Zahiri, H and Eves, R and Stevens, C and Hehemann, JH and Vidal-Melgosa, S and Davies, PL}, title = {Structural Basis of Ligand Selectivity by a Bacterial Adhesin Lectin Involved in Multispecies Biofilm Formation.}, journal = {mBio}, volume = {12}, number = {2}, pages = {}, pmid = {33824212}, issn = {2150-7511}, mesh = {Adhesins, Bacterial/*chemistry/*metabolism ; Binding Sites ; Biofilms/*growth & development ; Crystallography, X-Ray ; Lectins/*chemistry/*metabolism ; Ligands ; Marinomonas/chemistry/*metabolism ; Models, Molecular ; Protein Conformation ; }, abstract = {Carbohydrate recognition by lectins governs critical host-microbe interactions. MpPA14 (Marinomonas primoryensis PA14 domain) lectin is a domain of a 1.5-MDa adhesin responsible for a symbiotic bacterium-diatom interaction in Antarctica. Here, we show that MpPA14 binds various monosaccharides, with l-fucose and N-acetylglucosamine being the strongest ligands (dissociation constant [Kd ], ∼150 μM). High-resolution structures of MpPA14 with 15 different sugars bound elucidated the molecular basis for the lectin's apparent binding promiscuity but underlying selectivity. MpPA14 mediates strong Ca[2+]-dependent interactions with the 3,4-diols of l-fucopyranose and glucopyranoses, and it binds other sugars via their specific minor isomers. Thus, MpPA14 only binds polysaccharides like branched glucans and fucoidans with these free end groups. Consistent with our findings, adhesion of MpPA14 to diatom cells was selectively blocked by l-fucose, but not by N-acetyl galactosamine. The MpPA14 lectin homolog present in a Vibrio cholerae adhesin was produced and was shown to have the same sugar binding preferences as MpPA14. The pathogen's lectin was unable to effectively bind the diatom in the presence of fucose, thus demonstrating the antiadhesion strategy of blocking infection via ligand-based antagonists.IMPORTANCE Bacterial adhesins are key virulence factors that are essential for the pathogen-host interaction and biofilm formation that cause most infections. Many of the adhesin-driven cell-cell interactions are mediated by lectins. Our study reveals for the first time the molecular basis underlying the binding selectivity of a common bacterial adhesin lectin from the marine bacterium Marinomonas primoryensis, homologs of which are found in both environmental and pathogenic species. The lectin-ligand interactions illustrated at the atomic level guided the identification of a ligand that serves as an inhibitor to block bacterium-host adhesion. With conventional bactericidal antibiotics losing their potency due to resistance, our work gives critical insight into an antiadhesion strategy to treat bacterial infections.}, } @article {pmid33824174, year = {2021}, author = {Öcal, S and Özen, S and Nemutlu, E and Kart, D and Eylem, CC and Topeli, A}, title = {Salbutamol Delivered by Jet Nebulizer: Closed System Design and Impact of a Model Biofilm.}, journal = {Respiratory care}, volume = {66}, number = {9}, pages = {1440-1445}, doi = {10.4187/respcare.08142}, pmid = {33824174}, issn = {1943-3654}, mesh = {Administration, Inhalation ; Aerosols ; *Albuterol ; Biofilms ; *Bronchodilator Agents ; Equipment Design ; Humans ; Nebulizers and Vaporizers ; }, abstract = {BACKGROUND: Aerosol therapy is commonly used by intensivists during invasive mechanical ventilation. More information is needed to optimize outcomes. The first aim of this study was to assess the deposition of salbutamol on components of a closed mechanical ventilation system, both in the presence and absence of biofilm generated by Acinetobacter baumannii. The second aim was to evaluate the deposition of salbutamol, using a single dose and a double dose, delivered via a jet nebulizer placed between the flexible tube and the heat and moisture exchanger.

METHODS: A mechanical ventilator was connected to a standard system, and a jet nebulizer was placed between the heat and moisture exchanger and the flexible tube. Clinical isolates of A. baumanii were used to generate a biofilm layer on the endotracheal tube. Two amounts of salbutamol were delivered via the jet nebulizer. An analytical liquid chromatography tandem mass spectrometry method was developed to evaluate salbutamol deposition.

RESULTS: The presence of a biofilm on the endotracheal tube had no impact on salbutamol deposition (P = .83). There was no difference in surface deposition of salbutamol on component parts of the closed system in a comparison of a single dose and a double dose delivered via a jet nebulizer.

CONCLUSIONS: Our findings indicate that an A. baumannii biofilm had no impact on the extent of salbutamol deposition. Salbutamol deposition was comparatively low and could be delivered without removal of the heat and moisture exchanger.}, } @article {pmid33822631, year = {2021}, author = {Suleman Ismail Abdalla, S and Katas, H and Chan, JY and Ganasan, P and Azmi, F and Fauzi, MB}, title = {Gelatin Hydrogels Loaded with Lactoferrin-Functionalized Bio-Nanosilver as a Potential Antibacterial and Anti-Biofilm Dressing for Infected Wounds: Synthesis, Characterization, and Deciphering of Cytotoxicity.}, journal = {Molecular pharmaceutics}, volume = {18}, number = {5}, pages = {1956-1969}, doi = {10.1021/acs.molpharmaceut.0c01033}, pmid = {33822631}, issn = {1543-8392}, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry/pharmacokinetics ; *Bandages ; Biofilms/drug effects ; Drug Liberation ; Fibroblasts ; Gelatin/chemistry/toxicity ; Humans ; Hydrogels/*chemistry/toxicity ; Lactoferrin/chemistry ; Metal Nanoparticles/administration & dosage/chemistry ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects ; Silver/*administration & dosage/chemistry/pharmacokinetics ; Staphylococcus aureus/drug effects ; Toxicity Tests, Acute ; Wound Healing/drug effects ; Wound Infection/microbiology/*prevention & control ; }, abstract = {Gelatin hydrogels are attractive for wound applications owing to their well-defined structural, physical, and chemical properties as well as good cell adhesion and biocompatibility. This study aimed to develop gelatin hydrogels incorporated with bio-nanosilver functionalized with lactoferrin (Ag-LTF) as a dual-antimicrobial action dressing, to be used in treating infected wounds. The hydrogels were cross-linked using genipin prior to loading with Ag-LTF and characterized for their physical and swelling properties, rheology, polymer and actives interactions, and in vitro release of the actives. The hydrogel's anti-biofilm and antibacterial performances against S. aureus and P. aeruginosa as well as their cytotoxicity effects were assessed in vitro, including primary wound healing gene expression of human dermal fibroblasts (HDFs). The formulated hydrogels showed adequate release of AgNPs and LTF, with promising antimicrobial effects against both bacterial strains. The Ag-LTF-loaded hydrogel did not significantly interfere with the normal cellular functions as no alteration was detected for cell viability, migration rate, and expression of the target genes, suggesting the nontoxicity of Ag-LTF as well as the hydrogels. In conclusion, Ag-LTF-loaded genipin-cross-linked gelatin hydrogel was successfully synthesized as a new approach for fighting biofilms in infected wounds, which may be applied to accelerate healing of chronic wounds.}, } @article {pmid33822590, year = {2021}, author = {Lee, SW and Carnicelli, J and Getya, D and Gitsov, I and Phillips, KS and Ren, D}, title = {Biofilm Removal by Reversible Shape Recovery of the Substrate.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {15}, pages = {17174-17182}, pmid = {33822590}, issn = {1944-8252}, support = {R01 EB030621/EB/NIBIB NIH HHS/United States ; R21 AI142424/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Benzoyl Peroxide/chemistry ; Biofilms/*drug effects ; *Mechanical Phenomena ; Molecular Weight ; Pseudomonas aeruginosa/*drug effects/*physiology ; Temperature ; }, abstract = {Bacteria can colonize essentially any surface and form antibiotic resistant biofilms, which are multicellular structures embedded in an extracellular matrix secreted by the attached cells. To develop better biofilm control technologies, we recently demonstrated that mature biofilms can be effectively removed through on-demand shape recovery of a shape memory polymer (SMP) composed of tert-butyl acrylate (tBA). It was further demonstrated that such a dynamic substratum can sensitize the detached biofilm cells to antibiotics. However, this SMP can undergo shape change only once, limiting its application in long-term biofilm control. This motivated the present study, which aimed to prove the concept that biofilm can be effectively removed by repeated on-demand shape recovery. Reversible shape memory polymers (rSMPs) containing poly(ε-caprolactone) diisocyanatoethyl dimethacrylate (PCLDIMA) of varying molecular masses and butyl acrylate (BA) as a linker were synthesized by using benzoyl peroxide (BPO) as a thermal initiator. By comparison of several combinations of PCLDIMA of different molecular masses, a 2:1 weight ratio mixture of 2000 and 15000 g/mol PCLDIMA was the most promising because it had a shape transition (at 36.7 °C) close to body temperature. The synthesized rSMP demonstrated good reversible shape recovery and up to 94.3 ± 1.0% removal of 48 h Pseudomonas aeruginosa PAO1 biofilm cells after three consecutive shape recovery cycles. Additionally, the detached biofilm cells were found to be 5.0 ± 1.2 times more susceptible to 50 μg/mL tobramycin than the static control.}, } @article {pmid33821617, year = {2021}, author = {Chen, P and Lang, J and Franklin, T and Yu, Z and Yang, R}, title = {Reduced Biofilm Formation at the Air-Liquid-Solid Interface via Introduction of Surfactants.}, journal = {ACS biomaterials science & engineering}, volume = {}, number = {}, pages = {}, doi = {10.1021/acsbiomaterials.0c01691}, pmid = {33821617}, issn = {2373-9878}, abstract = {Reduced biofilm formation is highly desirable in applications ranging from transportation to separations and healthcare. Biofilms often form at the three-phase interface where air, liquid, and solid coexist due to the close proximity to nutrients and oxygen. Reducing biofilm formation at the triple interface presents challenges because of the conflicting requirements for hydrophobicity at the air-solid interface (for self-cleaning properties) and for hydrophilicity at the liquid-solid interface (for reduced foulant adhesion). Meeting those needs simultaneously likely entails a dynamic surface, capable of shifting the surface energy landscape in response to wetting conditions and thus enabling hydrophobicity in air and hydrophilicity in water. Here, we designed a facile approach to render existing surfaces resistant to biofilm formation at the triple interface. By adding trace amounts (∼0.1 mM) of surfactants, biofilm formation of Pseudomonas aeruginosa (known to form biofilm at the triple interface) was reduced on all surfaces tested, ranging from hydrophilic to hydrophobic, polar to nonpolar. That reduced fouling was not a result of the known antimicrobial effects. Instead, it was attributed to the surface-adsorbed surfactants that dynamically control surface energy at the triple interface. To further understand the effect of surfactant-surface interactions on biofilm reduction, we systematically varied the surfactant charge type and surface properties (surface energy and charge). Electrostatic interactions between surfactants and surfaces were identified as an influential factor when predicting the relative fouling reduction upon introduction of surfactants. Nevertheless, biofilm formation was reduced even on the charge-neutral, fluorinated surface made of poly(1H, 1H, 2H, 2H-perfluorodecyl acrylate) by more than 2-fold simply via adding 0.2 mM dodecyl trimethylammonium chloride or 0.3 mM sodium dodecyl sulfate. Given its robustness, this strategy is broadly applicable for reducing fouling on existing surfaces, which in turn improves the cost-effectiveness of membrane separations and mitigates contaminations and nosocomial infections in healthcare.}, } @article {pmid33820926, year = {2021}, author = {Lima-Holanda, AT and de Sousa, ET and Nobre-Dos-Santos, M and Steiner-Oliveira, C}, title = {The role of mechanical control of biofilm in the salivary pH after sucrose exposure in children with early childhood caries.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {7496}, pmid = {33820926}, issn = {2045-2322}, mesh = {*Biofilms ; Buffers ; Carbonic Anhydrases/metabolism ; Child ; Dental Caries/*microbiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Male ; Saliva/enzymology/*microbiology ; Salivation/physiology ; Sucrose/*adverse effects ; alpha-Amylases/metabolism ; }, abstract = {This quasi-experimental study sought to investigate if the mechanical control of biofilm (3-times-a-day) modifies the saliva's ability to buffer the oral environment after 20% sucrose rinse (SR20%) in children with early childhood caries (ECC). Here, SR20% reduced the saliva's pH in both groups and the mechanical control of biofilm had a greater effect on this parameter after SR20% in CF children. The mechanical control of biofilm evidenced a higher buffering capacity in CF children before SR20%, which was not observed after SR20%. Otherwise, the absence of mechanical control of biofilm showed that buffering capacity was comparable in the two groups before SR20%, whereas after SR20% the saliva's buffering capacity of CF children was higher than ECC children. When biofilm was mechanically controlled, carbonic anhydrase VI activity did not change after SR20% whereas the absence of mechanical control of biofilm reduced this enzyme activity after SR20%. In conclusion, the mechanical control of biofilm did not change saliva's ability to buffer the oral environment after SR20% in children with ECC. On the other hand, CF children appeared to regulate more effectively the saliva's pH than ECC children while the absence of mechanical control of biofilm mediated their pH-modifying ability after SR20%.}, } @article {pmid33819880, year = {2021}, author = {Zhang, M and Gao, J and Fan, Y and Liu, Q and Zhu, C and Ge, L and He, C and Wu, J}, title = {Comparisons of nitrite accumulation, microbial behavior and nitrification kinetic in continuous stirred tank (ST) and plug flow (PF) moving bed biofilm reactors.}, journal = {Chemosphere}, volume = {278}, number = {}, pages = {130410}, doi = {10.1016/j.chemosphere.2021.130410}, pmid = {33819880}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Kinetics ; *Nitrification ; *Nitrites ; }, abstract = {Two types of continuous stirred tank moving bed biofilm reactors (ST-MBBR) and plug flow MBBR (PF-MBBR) were compared for nitrification. PF-MBBR showed strong shock resistance to temperature, and ammonium oxidation ratio (AOR) was 9.63% higher than that in the ST-MBBR, although the average biomass and biofilm thickness of ST-MBBR were 7.32-18.59%, 9.44-14.06% higher than those in the PF-MBBR. Meanwhile, a lower nitrite accumulation ratio (NAR) was observed (54.88%) in the PF-MBBR than the ST-MBBR (78.92%) due to different operation modes, and the divergence was demonstrated by the microbial quantitative analysis. Nitrification kinetics revealed that the temperature coefficient (θ) in the ST-MBBR (1.068) was much higher than that in the PF-MBBR (1.006-1.015), proving the contrasting nitrification performances caused by temperature shock. According to the Monod equation, the half-saturation coefficient (KN) in the ST-MBBR was 0.19 mg/L while it varied around 0.12-0.24 mg/L in the PF-MBBR, revealing various NH4[+] affinity owing to different biofilm thickness and microbial composition. Finally, MBBR optimization related to operation mode, temperature, and free ammonium (FA) inhibition for nitrite accumulation was discussed.}, } @article {pmid33819769, year = {2021}, author = {Merigo, E and Bufflier, P and Rocca, JP and Chevalier, M and Medioni, E and Meng, Z and Fornaini, C}, title = {Bactericidal effect of Er,Cr:YSGG laser irradiation on endodontic biofilm: An ex vivo study.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {218}, number = {}, pages = {112185}, doi = {10.1016/j.jphotobiol.2021.112185}, pmid = {33819769}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/drug effects ; Chromium/*chemistry/pharmacology ; Enterococcus faecalis/radiation effects ; Erbium/*chemistry/pharmacology ; Humans ; Lasers, Solid-State ; Low-Level Light Therapy/*methods ; Porphyromonas gingivalis/radiation effects ; Prevotella intermedia/radiation effects ; Streptococcus salivarius/radiation effects ; Tooth Root/*drug effects ; }, abstract = {AIM: This ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm.

MATERIALS AND METHODS: Seventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s.

RESULTS: The observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present. The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed.

CONCLUSION: In those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.}, } @article {pmid33819664, year = {2021}, author = {Acevedo Alonso, V and Kaiser, T and Babist, R and Fundneider, T and Lackner, S}, title = {A multi-component model for granular activated carbon filters combining biofilm and adsorption kinetics.}, journal = {Water research}, volume = {197}, number = {}, pages = {117079}, doi = {10.1016/j.watres.2021.117079}, pmid = {33819664}, issn = {1879-2448}, mesh = {Adsorption ; Biofilms ; Charcoal ; Kinetics ; Waste Disposal, Fluid ; *Water Pollutants, Chemical/analysis ; *Water Purification ; }, abstract = {Along with the rise of biological active granular activated carbon (bGAC) filtration as advanced treatment technology for wastewater treatment plant (WWTP) effluents, the mathematical representation of such systems is gaining increasing importance. This work introduces a model that describes the performance of bGAC-filters for Dissolved Organic Carbon (DOC) removal from a WWTP effluent. The DOC removal within bGAC-filters is accomplished by two mechanisms: adsorptive removal and biological transformation. An appropriate representation of the adsorptive removal requires the DOC to be divided into fictive fractions according to its adsorbability. Likewise, a further DOC classification according to its biodegradability is necessary. Modeling a bGAC-filter then becomes a multi-component adsorption problem, with the simultaneous occurrence of DOC degradation within a biofilm. For dealing with this modeling task, this work integrated the Ideal Adsorbed Solution (IAS) theory into a traditional biofilm model compatible with the Activated Sludge Model (ASM) Framework. For the description of the adsorption dynamics, a Freundlich isotherm for the equilibrium and a pseudo first order model for the kinetics were selected. The biofilm consisted of heterotrophic bacteria able to oxidize DOC using oxygen as electron acceptor. The correctness of the model was evaluated using experimental data from a pilot plant. The predicted DOC breakthrough curve satisfactorily fitted the experimental measurements for empty bed contact times (EBCT) of 6, 12, 24 and 33 min. Moreover, the model predicted the relationship between EBCT, DOC removal and bGAC-filter lifespan. The developed model is the first that combines multi-component adsorption and biofilm kinetics in a wastewater treatment context.}, } @article {pmid33819383, year = {2021}, author = {Ganguly, T and Peterson, AM and Kajfasz, JK and Abranches, J and Lemos, JA}, title = {Zinc import mediated by AdcABC is critical for colonization of the dental biofilm by Streptococcus mutans in an animal model.}, journal = {Molecular oral microbiology}, volume = {36}, number = {3}, pages = {214-224}, pmid = {33819383}, issn = {2041-1014}, support = {R01 DE019783/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Biofilms ; *Dental Caries ; Models, Animal ; Rats ; *Streptococcus mutans/genetics ; Zinc ; }, abstract = {Trace metals are essential to all domains of life but toxic when found at high concentrations. Although the importance of iron in host-pathogen interactions is firmly established, contemporary studies indicate that other trace metals, including manganese and zinc, are also critical to the infectious process. In this study, we sought to identify and characterize the zinc uptake system(s) of Streptococcus mutans, a keystone pathogen in dental caries and a causative agent of bacterial endocarditis. Different than other pathogenic bacteria, including several streptococci, that encode multiple zinc import systems, bioinformatic analysis indicated that the S. mutans core genome encodes a single, highly conserved, zinc importer commonly known as AdcABC. Inactivation of the genes coding for the metal-binding AdcA (ΔadcA) or both AdcC ATPase and AdcB permease (ΔadcCB) severely impaired the ability of S. mutans to grow under zinc-depleted conditions. Intracellular metal quantifications revealed that both mutants accumulated less zinc when grown in the presence of a subinhibitory concentration of a zinc-specific chelator. Notably, the ΔadcCB strain displayed a severe colonization defect in a rat oral infection model. Both Δadc strains were hypersensitive to high concentrations of manganese, showed reduced peroxide tolerance, and formed less biofilm in sucrose-containing media when cultivated in the presence of the lowest amount of zinc that support their growth, but not when zinc was supplied in excess. Collectively, this study identifies AdcABC as the major high affinity zinc importer of S. mutans and provides preliminary evidence that zinc is a growth-limiting factor within the dental biofilm.}, } @article {pmid33815313, year = {2021}, author = {Raeder, SB and Sandbakken, ET and Nepal, A and Løseth, K and Bergh, K and Witsø, E and Otterlei, M}, title = {Novel Peptides Targeting the β-Clamp Rapidly Kill Planktonic and Biofilm Staphylococcus epidermidis Both in vitro and in vivo.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {631557}, pmid = {33815313}, issn = {1664-302X}, abstract = {Antimicrobial resistance is an increasing threat to global health and challenges the way we treat infections. Peptides containing the PCNA interacting motif APIM (APIM-peptides) were recently shown to bind to the bacterial PCNA homolog, the beta (β)-clamp, and to have both antibacterial and anti-mutagenic activities. In this study we explore the antibacterial effects of these peptides on Staphylococcus epidermidis, a bacterial species commonly found in prosthetic joint infections (PJI). Drug-resistant bacterial isolates from PJIs often lead to difficult-to-treat chronic infections. We show that APIM-peptides have a rapid bactericidal effect which when used at sublethal levels also increase the efficacy of gentamicin. In addition, APIM-peptides reduce development and eliminate already existing S. epidermidis biofilm. To study the potential use of APIM-peptides to prevent PJI, we used an in vivo bone graft model in rats where APIM-peptide, gentamicin, or a combination of the two was added to cement. The bone grafts containing cement with the combination was more effective than cement containing only gentamicin, which is the current standard of care. In summary, these results suggest that APIM-peptides can be a promising new drug candidate for anti-infective implant materials to use in the fight against resistant bacteria and chronic PJI.}, } @article {pmid33813481, year = {2021}, author = {Kovalchuk, VP and Nazarchuk, OA and Burkot, VM and Fomina, NS and Prokopchuk, ZM and Dobrovanov, O}, title = {BIOFILM FORMING ACTIVITY OF NON-FERMENTING GRAM-NEGATIVE BACTERIA.}, journal = {Wiadomosci lekarskie (Warsaw, Poland : 1960)}, volume = {74}, number = {2}, pages = {252-256}, pmid = {33813481}, issn = {0043-5147}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; *Biofilms ; *Gram-Negative Bacteria ; Humans ; Pseudomonas aeruginosa ; }, abstract = {OBJECTIVE: The aim: To study the influence of chemical, physical factors on the biofilm forming activity of P. aeruginosa, A. baumannii.

PATIENTS AND METHODS: Materials and methods: Biofilm forming activity of P. aeruginosa (10 isolates) and A. baumannii (10 isolates) was studied in nutrient media of different composition. There was used the method in 96-well crystalline violet staining plates with spectrophotometry (STAT FAX®4300, wavelength of 620 nm).

RESULTS: Results: Results showed that in standard medium (trypto-soy broth), strains of P. aeruginosa (90%) and A. baumannii (60%) obtained high biofilm forming activity. A. baumannii formed biofilms even in sterile water. Biofilm forming activity of urease positive P. aeruginosa increased in the medium with 1.0% urea. Both Acinetbacteria and Pseudomonas intensively produced their biofilms in the presence of 5% serum or sub-bacteriostatic concentrations of levofloxacin in the media. High concentrations of sodium chloride inhibited their biofilm activity.

CONCLUSION: Conclusions: Isolates of Acinetobacter and Pseudomonas obtain the protective biofilm-forming ability under such adverse environmental conditions as insufficient nutrients, high osmotic pressure, the presence of antibiotics but at high concentrations sodium chloride biofilm-formation is stimulated only in the first bacteria and suppressed in the second one.}, } @article {pmid33813017, year = {2021}, author = {de Paula, GS and Oliveira, MC and Sales, LS and Boriollo, M and Rodrigues, LKA and Nobre-Dos-Santos, M and Steiner-Oliveira, C}, title = {Antimicrobial photodynamic therapy mediated by methylene blue coupled to β-cyclodextrin reduces early colonizing microorganisms from the oral biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {34}, number = {}, pages = {102283}, doi = {10.1016/j.pdpdt.2021.102283}, pmid = {33813017}, issn = {1873-1597}, mesh = {*Anti-Infective Agents ; Biofilms ; Methylene Blue/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Streptococcus mutans ; *beta-Cyclodextrins ; }, abstract = {OBJECTIVE: To test the effect of antimicrobial photodynamic therapy (A-PDT) on the oral biofilm formed with early colonizing microorganisms, using the photosensitizer methylene blue coupled with β-cyclodextrin nanoparticles and red light sources laser or LED (λ =660 nm).

METHODS: The groups were divided into (n = 3, in triplicate): C (negative control, 0.9 % NaCl), CX (positive control, 0.2 % chlorhexidine), P (Photosensitizer/Nanoparticle), L (Laser), LED (light-emitting diode), LP (Laser + Photosensitizer/Nanoparticle) and LEDP (LED + Photosensitizer/Nanoparticle). A multispecies biofilm composed ofS. gordonii, S. oralis, S. mitis, and S. sanguinis was grown in microplates containing BHI supplemented with 1% sucrose (w/v) for 24 h. Light irradiations were applied with a laser at 9 J for 90 s (320 J/cm[2]), or with LED, at 8.1 J for 90 s (8.1 J/cm[2]). The microbial reduction was assessed by counting viable biofilm microorganisms in selective culture media, before and after the treatments. Data normality was assessed by the Shapiro-Wilk test, and the results were submitted to Kruskal-Wallis analysis, followed by Dunn's test, with a significance level of 5%.

RESULTS: The groups LP and LEDP were able to significantly reduce the biofilm microorganism counts by as much as 4 log10 times compared to the negative control group (p < 0.05) and did not statistically differ from the positive control group (CX) (p > 0.05).

CONCLUSION: The A-PDT mediated by encapsulated β-cyclodextrin methylene blue irradiated by Laser or LED was effective in the microbial reduction of multispecies biofilm composed of early colonizing microorganisms.}, } @article {pmid33812176, year = {2021}, author = {Singh, KS and Kumar, R and Chauhan, A and Singh, N and Sharma, R and Singh, D and Singh, SK}, title = {Knockout of MRA_1916 in Mycobacterium tuberculosis H37Ra affects its growth, biofilm formation, survival in macrophages and in mice.}, journal = {Tuberculosis (Edinburgh, Scotland)}, volume = {128}, number = {}, pages = {102079}, doi = {10.1016/j.tube.2021.102079}, pmid = {33812176}, issn = {1873-281X}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; D-Amino-Acid Oxidase/*genetics ; Gene Knockout Techniques ; Macrophages/*microbiology ; Mice ; Mice, Inbred BALB C ; Mycobacterium tuberculosis/*genetics/growth & development ; }, abstract = {Mycobacterium tuberculosis H37Ra (Mtb-Ra) ORF MRA_1916 is annotated as a D-amino acid oxidase (DAO). These enzymes perform conversion of d-amino acids to corresponding imino acids followed by conversion into α-keto-acids. In the present study Mtb-Ra recombinants with DAO knockout (KO) and knockout complemented with DAO over-expressing plasmid (KOC) were constructed. The growth studies showed loss of growth of KO in medium containing glycerol as a primary carbon source. Substituting glycerol with acetate or with FBS addition, restored the growth. Growth was also restored in complemented strain (KOC). KO showed increased permeability to hydrophilic dye EtBr and reduced biofilm formation. Also, its survival in macrophages was low. Phagosome maturation studies suggested enhanced colocalization of KO, compared to WT, with lysosomal marker cathepsin D. Also, an increased intensity of Rab5 and iNOS was observed in macrophages infected with KO, compared to WT and KOC. The in vivo survival studies showed no increase in CFU of KO. This is the first study to show functional relevance of DAO encoded by MRA_1916 for Mtb-Ra growth on glycerol, its permeability and biofilm formation. Also, this study clearly demonstrates that DAO deletion leads to Mtb-Ra failing to grow in macrophages and in mice.}, } @article {pmid33812139, year = {2021}, author = {Huang, J and Chu, R and Chang, T and Cheng, P and Jiang, J and Yao, T and Zhou, C and Liu, T and Ruan, R}, title = {Modeling and improving arrayed microalgal biofilm attached culture system.}, journal = {Bioresource technology}, volume = {331}, number = {}, pages = {124931}, doi = {10.1016/j.biortech.2021.124931}, pmid = {33812139}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; Light ; *Microalgae ; }, abstract = {A microalgal biofilm-attached-system is an alternative cultivation method, that offers potential advantages of improved biomass productivity, efficient harvesting, and water saving. These biofilm systems have been widely tested and utilized for microalgal biomass production and wastewater treatment. This research a microalgal growth model for the biofilm attached culture system has been developed and experimentally validated, both, in single and arrayed biofilm systems. It has been shown that the model has the capability to accurately describe microalgae growth. Moreover, via the model simulation, it was observed that system structural parameters, light dilution rate, and light intensity significantly affected the culture performance. The limitations, and improvement aspects of the model, are also discussed in this study. To our knowledge, this is the first time that a mathematical model for an arrayed-biofilm-attached-system has been developed and validated. This model will certainly be helpful in the design, improvement, optimization, and evaluation of the biofilm-attached-systems.}, } @article {pmid33812123, year = {2021}, author = {Zhang, H and Gong, W and Zeng, W and Chen, R and Lin, D and Li, G and Liang, H}, title = {Bacterial-algae biofilm enhance MABR adapting a wider COD/N ratios wastewater: Performance and mechanism.}, journal = {The Science of the total environment}, volume = {781}, number = {}, pages = {146663}, doi = {10.1016/j.scitotenv.2021.146663}, pmid = {33812123}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; *Bioreactors ; Denitrification ; Nitrification ; Nitrogen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Although membrane aerated biofilm reactor (MABR) is promising in nitrogen removal due to its counter-diffusion biofilms structure, it still cannot adapt a wider COD/N ratios wastewater. In this condition, expanding the MABR applicability range in different COD/N ratio wastewater is necessary. In this study, a bacterial-algae biofilm, instead of bacteria biofilm, supporting membrane aerated biofilm reactor (MABAR) was constructed, and the performance was compared to MABR. Results showed that the total nitrogen (TN) removal efficiency was promoted significantly in MABAR regardless of the COD/N ratio. Compared to MABR, effluent TN concentration in COD/N ratio of 2, 5, and 8 declined by 14.34 mg/L, 0.50 mg/L, and 12.10 mg/L, respectively. Nitrification inhibition test suggested that algae assimilation made an obvious contribution (at least 18.18 mg/L) to the NH4[+]-N removal in MABAR. Besides, redundancy analysis (RDA) indicates that MABAR has a negative correlation with Nitrospirae but is positively correlated with NH4[+]-N removal load. These results are consistent with the kinetics result that algae assimilation, instead of nitrification-denitrification, is responsible for the nitrogen removal in MABAR. Therefore, the change of nitrogen removal route further gave MABAR excellent adaptability and impact resistance to address wastewater with different COD/N ratios, which is conducive to its wide application.}, } @article {pmid33811867, year = {2021}, author = {Li, XY and Peng, P and Wang, WK and Wang, SY and Feng, L and Zhang, YC and Xu, J}, title = {Particle electrode materials dependent tetrabromobisphenol A degradation in three-dimensional biofilm electrode reactors.}, journal = {Environmental research}, volume = {197}, number = {}, pages = {111089}, doi = {10.1016/j.envres.2021.111089}, pmid = {33811867}, issn = {1096-0953}, mesh = {Biofilms ; *Bioreactors ; Electrodes ; *Polybrominated Biphenyls ; }, abstract = {The completely biological degradation of Tetrabromobisphenol A (TBBPA) contaminant is challenging. Bio-electrochemical systems are efficient to promote electrons transfer between microbes and pollutants to improve the degradation of refractory contaminants. In particular, three-dimensional biofilm electrode reactors (3DBERs), integrating the biofilm with particle electrodes, represent a novel bio-electrochemical technology with superior treatment performances. In this study, the electroactive biofilm is cultured and acclimated on two types of particle electrodes, granular activated carbon (GAC) and granular zeolite (GZ), to degrade the target pollutant TBBPA in 3DBERs. Compared to GZ, GAC materials are more favorable for biofilm formation in terms of high specific surface area and good conductivity. The genus of Thauera is efficiently enriched on both GAC and GZ particles, whose growth is promoted by the electricity. By applying 5 V voltage, TBBPA can be removed by over 95% in 120 min whether packing GAC or GZ particle electrodes in 3DBERs. The synergy of electricity and biofilm in TBBPA degradation was more significant in GAC packed 3DBER, because the improved microbial activity by electrical stimulation accelerates debromination rate and hence the decomposition of TBBPA. Applying electricity also promotes TBBPA degradation in GZ packed 3DBER mainly due to the enhanced electrochemical effects. Roles of particle electrode materials in TBBPA removal are distinguished in this work, bringing new insights into refractory wastewater treatment by 3DBERs.}, } @article {pmid33811025, year = {2021}, author = {Wang, K and Li, X and Yang, C and Song, S and Cui, C and Zhou, X and Deng, Y}, title = {A LysR Family Transcriptional Regulator Modulates Burkholderia cenocepacia Biofilm Formation and Protease Production.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {12}, pages = {e0020221}, pmid = {33811025}, issn = {1098-5336}, mesh = {Bacterial Proteins/*physiology ; Biofilms/*growth & development ; Burkholderia cenocepacia/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Mutation ; Peptide Hydrolases/metabolism ; Phenotype ; *Quorum Sensing ; Transcription Factors/*physiology ; }, abstract = {Quorum-sensing (QS) signals are widely employed by bacteria to regulate biological functions in response to cell densities. Previous studies showed that Burkholderia cenocepacia mostly utilizes two types of QS systems, including the N-acylhomoserine lactone (AHL) and cis-2-dodecenoic acid (BDSF) systems, to regulate biological functions. We demonstrated here that a LysR family transcriptional regulator, Bcal3178, controls the QS-regulated phenotypes, including biofilm formation and protease production, in B. cenocepacia H111. Expression of Bcal3178 at the transcriptional level was obviously downregulated in both the AHL-deficient and BDSF-deficient mutant strains compared to the wild-type H111 strain. It was further identified that Bcal3178 regulated target gene expression by directly binding to the promoter DNA regions. We also revealed that Bcal3178 was directly controlled by the AHL system regulator CepR. These results show that Bcal3178 is a new downstream component of the QS signaling network that modulates a subset of genes and functions coregulated by the AHL and BDSF QS systems in B. cenocepacia. IMPORTANCE Burkholderia cenocepacia is an important opportunistic pathogen in humans that utilizes the BDSF and AHL quorum-sensing (QS) systems to regulate biological functions and virulence. We demonstrated here that a new downstream regulator, Bcal3178 of the QS signaling network, controls biofilm formation and protease production. Bcal3178 is a LysR family transcriptional regulator modulated by both the BDSF and AHL QS systems. Furthermore, Bcal3178 controls many target genes, which are regulated by the QS systems in B. cenocepacia. Collectively, our findings depict a novel molecular mechanism with which QS systems regulate some target gene expression and biological functions by modulating the expression level of a LysR family transcriptional regulator in B. cenocepacia.}, } @article {pmid33810849, year = {2022}, author = {Martínez-Serna, IV and Magdaleno, MO and Cepeda-Bravo, JA and Romo-Ramírez, GF and Sánchez-Vargas, LO}, title = {Does microwave and hydrogen peroxide disinfection reduce Candida albicans biofilm on polymethyl methacrylate denture surfaces?.}, journal = {The Journal of prosthetic dentistry}, volume = {128}, number = {5}, pages = {1068-1074}, doi = {10.1016/j.prosdent.2021.02.012}, pmid = {33810849}, issn = {1097-6841}, mesh = {*Candida albicans ; *Polymethyl Methacrylate/pharmacology ; Hydrogen Peroxide/pharmacology ; Disinfection ; Microwaves/therapeutic use ; Saline Solution/pharmacology ; Biofilms ; Dentures/microbiology ; }, abstract = {STATEMENT OF PROBLEM: Whether the disinfection of polymethyl methacrylate (PMMA) dentures eliminates Candida albicans biofilm is unclear.

PURPOSE: The purpose of this in vitro study was to determine the antimicrobial effect of immersion in hydrogen peroxide (H2O2) and subsequent application of microwaves on the formation of C albicans biofilm on the surface of polished and unpolished PMMA disks.

MATERIAL AND METHODS: Polished and unpolished PMMA disks (n=40) were mounted in a Center for Disease Control (CDC) biofilm reactor by adding yeast-dextrose-peptone (YPD) broth inoculated with C albicans in a cell suspension for 24 hours. After this period, the PMMA disks (n=8) were disinfected with 5 different solutions: saline solution, 1% sodium hypochlorite (NaOCl), H2O2, H2O2 microwaved at 650 W for 3 minutes (H2O2/μw), and distilled water microwaved at 650 W for 3 minutes (H2O/μw). On the polished and unpolished surface of each disk, arbitrary fluorescence units (AFU) were quantified with the live/dead bacterial viability kit (Invitrogen) by using confocal laser scanning microscopy (CLSM) to evaluate 10 different areas of each surface; these were counted as the colony-forming units (CFUs). The mean values were compared by using the Mann-Whitney U test (α=.05).

RESULTS: Polished surfaces disinfected with H2O2/μw obtained the lowest viable cells (9.76 AFU) and nonviable cells (12.46 AFU) compared with H2O/μw and H2O2. In the unpolished surface the lowest mean values of viable cells (14.64 AFU) and nonviable cells (12.46 AFU) were obtained for the PMMA disks disinfected with H2O/μw compared with H2O2/μw and H2O2. Both polished and unpolished disks showed significant difference (P<.05) compared with the group of PMMA disks immersed in saline solution. No CFUs were detected in the polished or unpolished PMMA disks immersed in H2O2/μw or in NaOCl.

CONCLUSIONS: H2O2 alone did not eliminate the formation of the biofilm of C albicans; however, in combination with the use of the microwave at 650 W for 3 minutes, the biofilm formation of C albicans on polished surfaces was reduced. The number of AFUs of viable-nonviable cells and CFUs depended on whether the surfaces are polished or unpolished.}, } @article {pmid33810292, year = {2021}, author = {Rao, H and Choo, S and Rajeswari Mahalingam, SR and Adisuri, DS and Madhavan, P and Md Akim, A and Chong, PP}, title = {Approaches for Mitigating Microbial Biofilm-Related Drug Resistance: A Focus on Micro- and Nanotechnologies.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {7}, pages = {}, pmid = {33810292}, issn = {1420-3049}, support = {FRGS/1/2019/SKK11/TAYLOR/01/1//Malaysian Ministry of Higher Education Fundamental Research Grant Scheme/ ; }, mesh = {*Antifungal Agents/pharmacology/therapeutic use ; Bandages ; *Biocompatible Materials/pharmacology/therapeutic use ; *Biofilms/drug effects/growth & development ; Cross Infection/*therapy ; Drug Resistance, Fungal/*drug effects ; *Fungi/drug effects/physiology ; Humans ; Nanoparticles/*therapeutic use ; }, abstract = {Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting.}, } @article {pmid33810261, year = {2021}, author = {Coraça-Huber, DC and Steixner, S and Wurm, A and Nogler, M}, title = {Antibacterial and Anti-Biofilm Activity of Omega-3 Polyunsaturated Fatty Acids against Periprosthetic Joint Infections-Isolated Multi-Drug Resistant Strains.}, journal = {Biomedicines}, volume = {9}, number = {4}, pages = {}, pmid = {33810261}, issn = {2227-9059}, abstract = {Background: Implantable medical devices, such as prosthetics, catheters, and several other devices, have revolutionized medicine, but they increase the infection risk. In previous decades, commercially available antibiotics lost their activity against coagulase-negative Staphylococci (CoNS) and several other microorganisms. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are the two major omega-3 polyunsaturated fatty acids (ω-3 PUFAs) with antimicrobial properties. Materials and Methods: In this study, we tested the EPA and the DHA for its antibacterial and anti-biofilm activity in vitro against Staphylococcus epidermidis, Staphylococcus aureus, and different CoNS as reference strains and isolated from patients undergoing orthopedic treatment for implant infections. The tests were carried out with the strains in planktonic and biofilm form. Cytotoxicity assay was carried out with EPA and DHA using human gingival fibroblasts HGF-1. Results: The highest concentration of EPA and DHA promoted the complete killing of S. epidermidis 1457 and S. aureus ATCC 25923 in planktonic form. The fatty acids showed low activity against P. aeruginosa. EPA and DHA completely killed or significantly reduced the count of planktonic bacteria of the patient isolated strains. When incubated with media enriched with EPA and DHA, the biofilm formation was significantly reduced on S. epidermidis 1457 and not present on S. aureus ATCC 25923. The reduction or complete killing were also observed with the clinical isolates. The pre-formed biofilms showed reduction of the cell counting after treatment with EPA and DHA. Conclusion: In this study, the ω-3 PUFAs EPA and DHA showed antimicrobial and anti-biofilm activity in vitro against S. aureus, S. epidermidis, and P. aeruginosa, as well as against multi-drug resistant S. aureus and CoNS strains isolated from patients undergoing periprosthetic joint infections (PJI) treatment. Higher concentrations of the fatty acids showed killing activity on planktonic cells and inhibitory activity of biofilm formation. Although both substances showed antimicrobial activity, EPA showed better results in comparison with DHA. In addition, when applied on human gingival fibroblasts in vitro, EPA and DHA showed a possible protective effect on cells cultured in medium enriched with ethanol. Further studies are required to confirm the antimicrobial activity of EPA and DHA against multi-drug resistant strains and pan-drug resistant strains.}, } @article {pmid33809953, year = {2021}, author = {Perpetuini, G and Rossetti, AP and Battistelli, N and Arfelli, G and Tofalo, R}, title = {Adhesion Properties, Biofilm Forming Potential, and Susceptibility to Disinfectants of Contaminant Wine Yeasts.}, journal = {Microorganisms}, volume = {9}, number = {3}, pages = {}, pmid = {33809953}, issn = {2076-2607}, support = {Progetto DM61315 "Sviluppo della qualità delle produzioni vitivinicole abruzzesi".//Miur/ ; FARDIB-2019//University of Teramo/ ; }, abstract = {In this study, yeasts isolated from filter membranes used for the quality control of bottled wines were identified and tested for their resistance to some cleaning agents and potassium metabisulphite, adhesion to polystyrene and stainless-steel surfaces, and formation of a thin round biofilm, referred to as a MAT. A total of 40 strains were identified by rRNA internal transcribed spacer (ITS) restriction analysis and sequence analysis of D1/D2 domain of 26S rRNA gene. Strains belong to Pichia manshurica (12), Pichia kudriavzevii (9), Pichia membranifaciens (1), Candida sojae (6), Candida parapsilosis (3), Candida sonorensis (1), Lodderomyces elongisporus (2), Sporopachydermia lactativora (3), and Clavispora lusitaniae (3) species. Regarding the adhesion properties, differences were observed among species. Yeasts preferred planktonic state when tested on polystyrene plates. On stainless-steel supports, adhered cells reached values of about 6 log CFU/mL. MAT structures were formed only by yeasts belonging to the Pichia genus. Yeast species showed different resistance to sanitizers, with peracetic acid being the most effective and active at low concentrations, with minimum inhibitory concentration (MIC) values ranging from 0.08% (v/v) to 1% (v/v). C. parapsilosis was the most sensible species. Data could be exploited to develop sustainable strategies to reduce wine contamination and establish tailored sanitizing procedures.}, } @article {pmid33809238, year = {2021}, author = {Dimopoulou, M and Kefalloniti, V and Tsakanikas, P and Papanikolaou, S and Nychas, GE}, title = {Assessing the Biofilm Formation Capacity of the Wine Spoilage Yeast Brettanomyces bruxellensis through FTIR Spectroscopy.}, journal = {Microorganisms}, volume = {9}, number = {3}, pages = {}, pmid = {33809238}, issn = {2076-2607}, support = {T1EDK-04747//ESPA/ ; }, abstract = {Brettanomyces bruxellensis is a wine spoilage yeast known to colonize and persist in production cellars. However, knowledge on the biofilm formation capacity of B. bruxellensis remains limited. The present study investigated the biofilm formation of 11 B. bruxellensis strains on stainless steel coupons after 3 h of incubation in an aqueous solution. FTIR analysis was performed for both planktonic and attached cells, while comparison of the obtained spectra revealed chemical groups implicated in the biofilm formation process. The increased region corresponding to polysaccharides and lipids clearly discriminated the obtained spectra, while the absorption peaks at the specific wavenumbers possibly reveal the presence of β-glucans, mannas and ergosterol. Unsupervised clustering and supervised classification were employed to identify the important wavenumbers of the whole spectra. The fact that all the metabolic fingerprints of the attached versus the planktonic cells were similar within the same cell phenotype class and different between the two phenotypes, implies a clear separation of the cell phenotype; supported by the results of the developed classification model. This study represents the first to succeed at applying a non-invasive technique to reveal the metabolic fingerprint implicated in the biofilm formation capacity of B. bruxellensis, underlying the homogenous mechanism within the yeast species.}, } @article {pmid33809097, year = {2021}, author = {Al-Hadidi, A and Navarro, J and Goodman, SD and Bailey, MT and Besner, GE}, title = {Lactobacillus reuteri in Its Biofilm State Improves Protection from Experimental Necrotizing Enterocolitis.}, journal = {Nutrients}, volume = {13}, number = {3}, pages = {}, pmid = {33809097}, issn = {2072-6643}, support = {R01 GM123482/GM/NIGMS NIH HHS/United States ; NIH R01 GM123482/NH/NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Dextrans ; Enterocolitis, Necrotizing/*prevention & control ; Humans ; In Vitro Techniques ; Intestinal Mucosa/cytology/*metabolism/microbiology ; *Limosilactobacillus reuteri ; Microspheres ; Probiotics/*therapeutic use ; Rats ; Rats, Sprague-Dawley ; }, abstract = {Necrotizing enterocolitis (NEC) is a devastating disease predominately found in premature infants that is associated with significant morbidity and mortality. Despite decades of research, medical management with broad spectrum antibiotics and bowel rest has remained relatively unchanged, with no significant improvement in patient outcomes. The etiology of NEC is multi-factorial; however, gastrointestinal dysbiosis plays a prominent role in a neonate's vulnerability to and development of NEC. Probiotics have recently emerged as a new avenue for NEC therapy. However, current delivery methods are associated with potential limitations, including the need for at least daily administration in order to obtain any improvement in outcomes. We present a novel formulation of enterally delivered probiotics that addresses the current limitations. A single enteral dose of Lactobacillus reuteri delivered in a biofilm formulation increases probiotic survival in acidic gastric conditions, increases probiotic adherence to gastrointestinal epithelial cells, and reduces the incidence, severity, and neurocognitive sequelae of NEC in experimental models.}, } @article {pmid33809050, year = {2021}, author = {Rowińska, I and Szyperska-Ślaska, A and Zariczny, P and Pasławski, R and Kramkowski, K and Kowalczyk, P}, title = {Impact of the Diet on the Formation of Oxidative Stress and Inflammation Induced by Bacterial Biofilm in the Oral Cavity.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {6}, pages = {}, pmid = {33809050}, issn = {1996-1944}, abstract = {The diet is related to the diversity of bacteria in the oral cavity, and the less diverse microbiota of the oral cavity may favor the growth of pathogenic bacteria of all bacterial complexes. Literature data indicate that disturbances in the balance of the bacterial flora of the oral cavity seem to contribute to both oral diseases, including periodontitis, and systemic diseases. If left untreated, periodontitis can damage the gums and alveolar bones. Improper modern eating habits have an impact on the oral microbiome and the gut microbiome, which increase the risk of several chronic diseases, including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease and cancer. The subject of our consideration is the influence of the traditional diet on the formation of oxidative stress and inflammation caused by bacterial biofilm in the oral cavity. Through dental, biomedical and laboratory studies, we wanted to investigate the effect of individual nutrients contained in specific diets on the induction of oxidative stress inducing inflammation of the soft tissues in the oral cavity in the presence of residual supra- and subgingival biofilm. In our research we used different types of diets marked as W, T, B, F and noninvasively collected biological material in the form of bacterial inoculum from volunteers. The analyzed material was grown on complete and selective media against specific strains of all bacterial complexes. Additionally, the zones of growth inhibition were analyzed based on the disc diffusion method. The research was supplemented with dental and periodontological indicators. The research was supplemented by the application of molecular biology methods related to bacterial DNA isolation, PCR reactions and sequencing. Such selected methods constitute an ideal screening test for the analysis of oral bacterial microbiota. The obtained results suggest that certain types of diet can be an effective prophylaxis in the treatment of civilization diseases such as inflammation of the oral cavity along with periodontal tissues and gingival pockets.}, } @article {pmid33808527, year = {2021}, author = {Kensche, A and Reich, M and Hannig, C and Kümmerer, K and Hannig, M}, title = {Modification of the Lipid Profile of the Initial Oral Biofilm In Situ Using Linseed Oil as Mouthwash.}, journal = {Nutrients}, volume = {13}, number = {3}, pages = {}, pmid = {33808527}, issn = {2072-6643}, support = {HA 2718/14-3, HA 5192/2-3, KU 1271/6-3//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Adult ; Animals ; Bacterial Adhesion/drug effects ; *Biofilms ; Cattle ; Fatty Acids/analysis ; Humans ; Linseed Oil/*pharmacology ; Lipids/*chemistry ; Microscopy, Electron, Transmission ; Mouthwashes/*pharmacology ; Saliva/chemistry ; Young Adult ; alpha-Linolenic Acid/metabolism ; }, abstract = {Lipids are of interest for the targeted modification of oral bioadhesion processes. Therefore, the sustainable effects of linseed oil on the composition and ultrastructure of the in situ pellicle were investigated. Unlike saliva, linseed oil contains linolenic acid (18:3), which served as a marker for lipid accumulation. Individual splints with bovine enamel slabs were worn by five subjects. After 1 min of pellicle formation, rinses were performed with linseed oil for 10 min, and the slabs' oral exposure was continued for up to 2 or 8 h. Gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS) was used to characterize the fatty acid composition of the pellicle samples. Transmission electron microscopy was performed to analyze the ultrastructure. Extensive accumulation of linolenic acid was recorded in the samples of all subjects 2 h after the rinse and considerable amounts persisted after 8 h. The ultrastructure of the 2 h pellicle was less electron-dense and contained lipid vesicles when compared with controls. After 8 h, no apparent ultrastructural effects were visible. Linolenic acid is an excellent marker for the investigation of fatty acid accumulation in the pellicle. New preventive strategies could benefit from the accumulation of lipid components in the pellicle.}, } @article {pmid33808411, year = {2021}, author = {Pałka, K and Miazga-Karska, M and Pawłat, J and Kleczewska, J and Przekora, A}, title = {The Effect of Liquid Rubber Addition on the Physicochemical Properties, Cytotoxicity, and Ability to Inhibit Biofilm Formation of Dental Composites.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {7}, pages = {}, pmid = {33808411}, issn = {1996-1944}, support = {FN2/IM/2021//Ministry of Science and Higher Education in Poland within statutory activity of Lublin University of Technology/ ; DS3/2020//Ministry of Science and Higher Education in Poland within statutory activity of Medical University of Lublin/ ; }, abstract = {The aim of this study was to evaluate the effect of modification with liquid rubber on the adhesion to tooth tissues (enamel, dentin), wettability and ability to inhibit bacterial biofilm formation of resin-based dental composites. Two commercial composites (Flow-Art-flow type with 60% ceramic filler and Boston-packable type with 78% ceramic filler; both from Arkona Laboratorium Farmakologii Stomatologicznej, Nasutów, Poland) were modified by addition of 5% by weight (of resin) of a liquid methacrylate-terminated polybutadiene. Results showed that modification of the flow type composite significantly (p < 0.05) increased the shear bond strength values by 17% for enamel and by 33% for dentine. Addition of liquid rubber significantly (p < 0.05) reduced also hydrophilicity of the dental materials since the water contact angle was increased from 81-83° to 87-89°. Interestingly, modified packable type material showed improved antibiofilm activity against Steptococcus mutans and Streptococcus sanguinis (quantitative assay with crystal violet), but also cytotoxicity against eukaryotic cells since cell viability was reduced to 37% as proven in a direct-contact WST-8 test. Introduction of the same modification to the flow type material significantly improved its antibiofilm properties (biofilm reduction by approximately 6% compared to the unmodified material, p < 0.05) without cytotoxic effects against human fibroblasts (cell viability near 100%). Thus, modified flow type composite may be considered as a candidate to be used as restorative material since it exhibits both nontoxicity and antibiofilm properties.}, } @article {pmid33808050, year = {2021}, author = {Niedzielski, A and Chmielik, LP and Stankiewicz, T}, title = {The Formation of Biofilm and Bacteriology in Otitis Media with Effusion in Children: A Prospective Cross-Sectional Study.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {7}, pages = {}, pmid = {33808050}, issn = {1660-4601}, mesh = {*Bacteriology ; Biofilms ; Child ; Cross-Sectional Studies ; Haemophilus influenzae ; Humans ; *Otitis Media with Effusion/epidemiology ; Prospective Studies ; }, abstract = {BACKGROUND: Otitis media with effusion (OME) can cause serious complications such as hearing impairment or development delays. The aim of the study was to assess the microbiological profile of organisms responsible for OME and to determine if a biofilm formation can be observed.

METHODS: Ninety-nine samples from 76 patients aged from 6 months to 12 years were collected for microbiological and molecular studies.

RESULTS: In microbiological studies, pathogenic bacteria Haemophilus influenzae (38.89%), Streptococcus pneumoniae (33.33%), and Staphylococcus aureus MSSA (27.78%), as well as opportunistic bacteria Staphylococcus spp. (74.14%), Diphtheroids (20.69%), Streptococcus viridans (3.45%), and Neisseria spp. (1.72%) were found. The average degree of hearing loss in the group of children with positive bacterial culture was 35.9 dB, while in the group with negative bacterial culture it was 25.9 dB (p = 0.0008). The type of cultured bacteria had a significant impact on the degree of hearing impairment in children (p = 0.0192). In total, 37.5% of Staphylococcus spp. strains were able to form biofilm.

CONCLUSIONS: Staphylococcus spp. in OME may form biofilms, which can explain the chronic character of the disease. Pathogenic and opportunistic bacteria may be involved in the etiopathogenesis of OME. The degree of hearing loss was significantly higher in patients from which the positive bacterial cultures were obtained.}, } @article {pmid33807767, year = {2021}, author = {Kruk, M and Trząskowska, M}, title = {Analysis of Biofilm Formation on the Surface of Organic Mung Bean Seeds, Sprouts and in the Germination Environment.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {3}, pages = {}, pmid = {33807767}, issn = {2304-8158}, support = {2018/02/X/NZ9/02119//Narodowe Centrum Nauki/ ; }, abstract = {This study aimed to analyse the impact of sanitation methods on the formation of bacterial biofilms after disinfection and during the germination process of mung bean on seeds and in the germination environment. Moreover, the influence of Lactobacillus plantarum 299v on the growth of the tested pathogenic bacteria was evaluated. Three strains of Salmonella and E. coli were used for the study. The colony forming units (CFU), the crystal violet (CV), the LIVE/DEAD and the gram fluorescent staining, the light and the scanning electron microscopy (SEM) methods were used. The tested microorganisms survive in a small number. During germination after disinfection D2 (20 min H2O at 60 °C, then 15 min in a disinfecting mixture consisting of H2O, H2O2 and CH3COOH), the biofilms grew most after day 2, but with the DP2 method (D2 + L. plantarum 299v during germination) after the fourth day. Depending on the method used, the second or fourth day could be a time for the introduction of an additional growth-limiting factor. Moreover, despite the use of seed disinfection, their germination environment could be favourable for the development of bacteria and, consequently, the formation of biofilms. The appropriate combination of seed disinfection methods and growth inhibition methods at the germination stage will lead to the complete elimination of the development of unwanted microflora and their biofilms.}, } @article {pmid33807455, year = {2021}, author = {Qian, Z and Zhu, H and Zhao, D and Yang, P and Gao, F and Lu, C and Yin, Y and Kan, S and Chen, D}, title = {Probiotic Lactobacillus sp. Strains Inhibit Growth, Adhesion, Biofilm Formation, and Gene Expression of Bacterial Vaginosis-Inducing Gardnerella vaginalis.}, journal = {Microorganisms}, volume = {9}, number = {4}, pages = {}, pmid = {33807455}, issn = {2076-2607}, abstract = {Gardnerella vaginalis contributes significantly to bacterial vaginosis, which causes an ecological imbalance in vaginal microbiota and presents with the depletion of Lactobacillus sp. Lactobacillus supplementation was reported to be an approach to treat bacterial vaginosis. We investigated the applicability of three Lactobacillus sp. strains (Lactobacillus delbrueckii DM8909, Lactiplantibacillus plantarum ATCC14917, and Lactiplantibacillus plantarum ZX27) based on their probiotic abilities in vitro. The three candidate Lactobacillus sp. strains for bacterial vaginosis therapy showed distinct properties in auto-aggregation ability, hydrophobicity, adhesion to cervical epithelial cells, and survivability in 0.01% hydrogen peroxide. Lpb. plantarum ZX27 showed a higher yield in producing short-chain fatty acids and lactic acid among the three candidate strains, and all three Lactobacillus sp. strains inhibited the growth and adhesion of G. vaginalis. Furthermore, we discovered that the culture supernatant of Lactobacillus sp. exhibited anti-biofilm activity against G. vaginalis. In particular, the Lpb. plantarum ZX27 supernatant treatment decreased the expression of genes related to virulence factors, adhesion, biofilm formation, metabolism, and antimicrobial resistance in biofilm-forming cells and suspended cells. Moreover, Lactobacillus sp. decreased the upregulated expression of interleukin-8 in HeLa cells induced by G. vaginalis or hydrogen peroxide. These results demonstrate the efficacy of Lactobacillus sp. application for treating bacterial vaginosis by limiting the growth, adhesion, biofilm formation, and virulence properties of G. vaginalis.}, } @article {pmid33807451, year = {2021}, author = {Lu, Q and Zhang, N and Chen, C and Zhang, M and Zhao, D and An, S}, title = {The Dynamic Response of Nitrogen Transformation to the Dissolved Oxygen Variations in the Simulated Biofilm Reactor.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {7}, pages = {}, pmid = {33807451}, issn = {1660-4601}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; *Denitrification ; *Nitrogen/analysis ; Oxygen ; Waste Disposal, Fluid ; }, abstract = {Lab-scale simulated biofilm reactors, including aerated reactors disturbed by short-term aeration interruption (AE-D) and non-aerated reactors disturbed by short-term aeration (AN-D), were established to study the stable-state (SS) formation and recovery after disturbance for nitrogen transformation in terms of dissolved oxygen (DO), removal efficiency (RE) of NH4[+]-N and NO3[-]-N and activity of key nitrogen-cycle functional genes amoA and nirS (RNA level abundance, per ball). SS formation and recovery of DO were completed in 0.56-7.75 h after transition between aeration (Ae) and aeration stop (As). In terms of pollutant REs, new temporary SS formation required 30.7-52.3 h after Ae and As interruptions, and seven-day Ae/As interruptions required 5.0% to 115.5% longer recovery times compared to one-day interruptions in AE-D and AN-D systems. According to amoA activity, 60.8 h were required in AE-D systems to establish new temporary SS after As interruptions, and RNA amoA copies (copy number/microliter) decreased 88.5%, while 287.2 h were required in AN-D systems, and RNA amoA copies (copy number/microliter) increased 36.4 times. For nirS activity, 75.2-85.8 h were required to establish new SSs after Ae and As interruptions. The results suggested that new temporary SS formation and recovery in terms of DO, pollutant REs and amoA and nirS gene activities could be modelled by logistic functions. It is concluded that temporary SS formation and recovery after Ae and As interruptions occurred at asynchronous rates in terms of DO, pollutant REs and amoA and nirS gene activities. Because of DO fluctuations, the quantitative relationship between gene activity and pollutant RE remains a challenge.}, } @article {pmid33807362, year = {2021}, author = {Baidamshina, DR and Koroleva, VA and Olshannikova, SS and Trizna, EY and Bogachev, MI and Artyukhov, VG and Holyavka, MG and Kayumov, AR}, title = {Biochemical Properties and Anti-Biofilm Activity of Chitosan-Immobilized Papain.}, journal = {Marine drugs}, volume = {19}, number = {4}, pages = {}, pmid = {33807362}, issn = {1660-3397}, support = {19-34-90061//Russian Foundation for Basic Research/ ; MD-1982.2020.4//Council on grants of the President of the Russian Federation/ ; }, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Carica/*enzymology ; Chitosan/*chemistry ; *Drug Carriers ; Drug Compounding ; Enzyme Stability ; Hydrogen-Ion Concentration ; Molecular Weight ; Papain/isolation & purification/*pharmacology ; Staphylococcus aureus ; Staphylococcus epidermidis/drug effects/growth & development ; Temperature ; }, abstract = {Chitosan, the product of chitin deacetylation, is an excellent candidate for enzyme immobilization purposes. Here we demonstrate that papain, an endolytic cysteine protease (EC: 3.4.22.2) from Carica papaya latex immobilized on the matrixes of medium molecular (200 kDa) and high molecular (350 kDa) weight chitosans exhibits anti-biofilm activity and increases the antimicrobials efficiency against biofilm-embedded bacteria. Immobilization in glycine buffer (pH 9.0) allowed adsorption up to 30% of the total protein (mg g chitosan[-1]) and specific activity (U mg protein[-1]), leading to the preservation of more than 90% of the initial total activity (U mL[-1]). While optimal pH and temperature of the immobilized papain did not change, the immobilized enzyme exhibited elevated thermal stability and 6-7-fold longer half-life time in comparison with the soluble papain. While one-half of the total enzyme dissociates from both carriers in 24 h, this property could be used for wound-dressing materials design with dosed release of the enzyme to overcome the relatively high cytotoxicity of soluble papain. Our results indicate that both soluble and immobilized papain efficiently destroy biofilms formed by Staphylococcus aureus and Staphylococcus epidermidis. As a consequence, papain, both soluble and immobilized on medium molecular weight chitosan, is capable of potentiating the efficacy of antimicrobials against biofilm-embedded Staphylococci. Thus, papain immobilized on medium molecular weight chitosan appears a presumably beneficial agent for outer wound treatment for biofilms destruction, increasing antimicrobial treatment effectiveness.}, } @article {pmid33807139, year = {2021}, author = {Piras, C and Di Ciccio, PA and Soggiu, A and Greco, V and Tilocca, B and Costanzo, N and Ceniti, C and Urbani, A and Bonizzi, L and Ianieri, A and Roncada, P}, title = {S. aureus Biofilm Protein Expression Linked to Antimicrobial Resistance: A Proteomic Study.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {4}, pages = {}, pmid = {33807139}, issn = {2076-2615}, abstract = {Antimicrobial resistance (AMR) represents one of the most critical challenges that humanity will face in the following years. In this context, a "One Health" approach with an integrated multidisciplinary effort involving humans, animals and their surrounding environment is needed to tackle the spread of AMR. One of the most common ways for bacteria to live is to adhere to surfaces and form biofilms. Staphylococcus aureus (S. aureus) can form biofilm on most surfaces and in a wide heterogeneity of environmental conditions. The biofilm guarantees the survival of the S. aureus in harsh environmental conditions and represents an issue for the food industry and animal production. The identification and characterization of biofilm-related proteins may provide interesting insights into biofilm formation mechanisms in S. aureus. In this regard, the aims of this study were: (i) to use proteomics to compare proteomes of S. aureus growing in planktonic and biofilm forms in order to investigate the common features of biofilm formation properties of different strains; (ii) to identify specific biofilm mechanisms that may be involved in AMR. The proteomic analysis showed 14 differentially expressed proteins among biofilm and planktonic forms of S. aureus. Moreover, three proteins, such as alcohol dehydrogenase, ATP-dependent 6-phosphofructokinase, and fructose-bisphosphate aldolase, were only differentially expressed in strains classified as high biofilm producers. Differentially regulated catabolites metabolisms and the switch to lower oxygen-related metabolisms were related to the sessile conformation analyzed.}, } @article {pmid33806228, year = {2021}, author = {Gherasim, O and Popescu, RC and Grumezescu, V and Mogoșanu, GD and Mogoantă, L and Iordache, F and Holban, AM and Vasile, BȘ and Bîrcă, AC and Oprea, OC and Grumezescu, AM and Andronescu, E}, title = {MAPLE Coatings Embedded with Essential Oil-Conjugated Magnetite for Anti-Biofilm Applications.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {7}, pages = {}, pmid = {33806228}, issn = {1996-1944}, support = {16N/2019//Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii/ ; }, abstract = {The present study reports on the development and evaluation of nanostructured composite coatings of polylactic acid (PLA) embedded with iron oxide nanoparticles (Fe3O4) modified with Eucalyptus (Eucalyptus globulus) essential oil. The co-precipitation method was employed to synthesize the magnetite particles conjugated with Eucalyptus natural antibiotic (Fe3O4@EG), while their composition and microstructure were investigated using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The matrix-assisted pulsed laser evaporation (MAPLE) technique was further employed to obtain PLA/Fe3O4@EG thin films. Optimal experimental conditions for laser processing were established by complementary infrared microscopy (IRM) and scanning electron microscopy (SEM) investigations. The in vitro biocompatibility with eukaryote cells was proven using mesenchymal stem cells, while the anti-biofilm efficiency of composite PLA/Fe3O4@EG coatings was assessed against Gram-negative and Gram-positive pathogens.}, } @article {pmid33805651, year = {2021}, author = {Zand, E and Pfanner, H and Domig, KJ and Sinn, G and Zunabovic-Pichler, M and Jaeger, H}, title = {Biofilm-Forming Ability of Microbacterium lacticum and Staphylococcus capitis Considering Physicochemical and Topographical Surface Properties.}, journal = {Foods (Basel, Switzerland)}, volume = {10}, number = {3}, pages = {}, pmid = {33805651}, issn = {2304-8158}, support = {866346//Österreichische Forschungsförderungsgesellschaft/ ; }, abstract = {Biofilm characteristics of Microbacterium lacticum D84 (M. lacticum) and Staphylococcus capitis subsp. capitis (S. capitis) on polytetrafluoroethylene and AISI-304 stainless steel at early- (24, 48 h) and late-stage (144, 192 h) biofilm formation were investigated. M. lacticum biofilm structure was more developed compared to S. capitis, representing vastly mature biofilms with a strongly developed amorphous matrix, possibly extracellular polymeric substances (EPSs), at late-stage biofilm formation. S. capitis showed faster growth behavior but still resulted in a relatively flat biofilm structure. Strong correlations were found between several roughness parameters and S. capitis surface coverage (r ≥ 0.98), and between total surface free energy (γs) and S. capitis surface coverage (r = 0.89), while M. lacticum remained mostly unaffected. The pronounced ubiquitous biofilm characteristics make M. lacticum D84 a suitable model for biofilm research. Studying biofilm formation of these bacteria may help one understand bacterial adhesion on interfaces and hence reduce biofilm formation in the food industry.}, } @article {pmid33803736, year = {2021}, author = {Peng, TY and Lin, DJ and Mine, Y and Tasi, CY and Li, PJ and Shih, YH and Chiu, KC and Wang, TH and Hsia, SM and Shieh, TM}, title = {Biofilm Formation on the Surface of (Poly)Ether-Ether-Ketone and In Vitro Antimicrobial Efficacy of Photodynamic Therapy on Peri-Implant Mucositis.}, journal = {Polymers}, volume = {13}, number = {6}, pages = {}, pmid = {33803736}, issn = {2073-4360}, support = {MOST 109-2811-B-039-527//Ministry of Science and Technology, Taiwan/ ; MOST 108-2314-B-039-009-MY3//Ministry of Science and Technology, Taiwan/ ; MOST 108-2314-B-039-037//Ministry of Science and Technology, Taiwan/ ; CMU109-MF-32//China Medical University, Taiwan/ ; CMU109-S-17//China Medical University, Taiwan/ ; }, abstract = {Poly-ether-ether-ketone (PEEK) is an aesthetically pleasing natural material with good biocompatibility and shock absorption characteristics. The application of PEEK as a dental implant or abutment is expected to reduce the risk of failure and enhance aesthetics. Given that approximately one in 15 patients have allergic reactions to antibiotics, photodynamic therapy (PDT) has been gaining attention as an alternative treatment. Herein, the applicability of PEEK dental implants or abutments was investigated using material analyses, biofilm formation assay, and cell viability tests. The possible use of PDT for peri-implant mucositis was evaluated with the biofilm removal assay. The obtained data were analyzed based on the multivariate analysis of variance, paired t-tests, and the Pearson correlation coefficient (α = 0.05). The results revealed that PEEK was significantly less conducive to the formation of biofilms with S. mutans and A. actinomycetemcomitan (p < 0.001) but exhibited comparable MG-63 (human osteoblast-like) osteoblast cell viability (p > 0.05) to the other materials. PDT had similar antimicrobial efficacy and yielded similar biofilm removal effects to antibiotics. Altogether, these findings suggest that PEEK has attractive features and can serve as an alternative material for dental implants or abutments. In cases where peri-implant mucositis occurs, PDT can be used as an accessible therapeutic approach.}, } @article {pmid33803642, year = {2021}, author = {Dergham, Y and Sanchez-Vizuete, P and Le Coq, D and Deschamps, J and Bridier, A and Hamze, K and Briandet, R}, title = {Comparison of the Genetic Features Involved in Bacillus subtilis Biofilm Formation Using Multi-Culturing Approaches.}, journal = {Microorganisms}, volume = {9}, number = {3}, pages = {}, pmid = {33803642}, issn = {2076-2607}, support = {42280PF//Campus France/ ; }, abstract = {Surface-associated multicellular assemblage is an important bacterial trait to withstand harsh environmental conditions. Bacillus subtilis is one of the most studied Gram-positive bacteria, serving as a model for the study of genetic pathways involved in the different steps of 3D biofilm formation. B. subtilis biofilm studies have mainly focused on pellicle formation at the air-liquid interface or complex macrocolonies formed on nutritive agar. However, only few studies focus on the genetic features of B. subtilis submerged biofilm formation and their link with other multicellular models at the air interface. NDmed, an undomesticated B. subtilis strain isolated from a hospital, has demonstrated the ability to produce highly structured immersed biofilms when compared to strains classically used for studying B. subtilis biofilms. In this contribution, we have conducted a multi-culturing comparison (between macrocolony, swarming, pellicle, and submerged biofilm) of B. subtilis multicellular communities using the NDmed strain and mutated derivatives for genes shown to be required for motility and biofilm formation in pellicle and macrocolony models. For the 15 mutated NDmed strains studied, all showed an altered phenotype for at least one of the different culture laboratory assays. Mutation of genes involved in matrix production (i.e., tasA, epsA-O, cap, ypqP) caused a negative impact on all biofilm phenotypes but favored swarming motility on semi-solid surfaces. Mutation of bslA, a gene coding for an amphiphilic protein, affected the stability of the pellicle at the air-liquid interface with no impact on the submerged biofilm model. Moreover, mutation of lytF, an autolysin gene required for cell separation, had a greater effect on the submerged biofilm model than that formed at aerial level, opposite to the observation for lytABC mutant. In addition, B. subtilis NDmed with sinR mutation formed wrinkled macrocolony, less than that formed by the wild type, but was unable to form neither thick pellicle nor structured submerged biofilm. The results are discussed in terms of the relevancy to determine whether genes involved in colony and pellicle formation also govern submerged biofilm formation, by regarding the specificities in each model.}, } @article {pmid33803296, year = {2021}, author = {Shahed-Al-Mahmud, M and Roy, R and Sugiokto, FG and Islam, MN and Lin, MD and Lin, LC and Lin, NT}, title = {Phage φAB6-Borne Depolymerase Combats Acinetobacter baumannii Biofilm Formation and Infection.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {3}, pages = {}, pmid = {33803296}, issn = {2079-6382}, support = {MOST 108-2320-B-320-008-//Ministry of Science and Technology, Taiwan/ ; }, abstract = {Biofilm formation is one of the main causes of increased antibiotic resistance in Acinetobacter baumannii infections. Bacteriophages and their derivatives, such as tail proteins with depolymerase activity, have shown considerable potential as antibacterial or antivirulence agents against bacterial infections. Here, we gained insights into the activity of a capsular polysaccharide (CPS) depolymerase, derived from the tailspike protein (TSP) of φAB6 phage, to degrade A. baumannii biofilm in vitro. Recombinant TSP showed enzymatic activity and was able to significantly inhibit biofilm formation and degrade formed biofilms; as low as 0.78 ng, the inhibition zone can still be formed on the bacterial lawn. Additionally, TSP inhibited the colonization of A. baumannii on the surface of Foley catheter sections, indicating that it can be used to prevent the adhesion of A. baumannii to medical device surfaces. Transmission and scanning electron microscopy demonstrated membrane leakage of bacterial cells treated with TSP, resulting in cell death. The therapeutic effect of TSP in zebrafish was also evaluated and the results showed that the survival rate was significantly improved (80%) compared with that of the untreated control group (10%). Altogether, we show that TSP derived from φAB6 is expected to become a new antibiotic against multi-drug resistant A. baumannii and a biocontrol agent that prevents the formation of biofilms on medical devices.}, } @article {pmid33802588, year = {2021}, author = {Schestakow, A and Guth, MS and Eisenmenger, TA and Hannig, M}, title = {Evaluation of Anti-Biofilm Activity of Mouthrinses Containing Tannic Acid or Chitosan on Dentin In Situ.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {5}, pages = {}, pmid = {33802588}, issn = {1420-3049}, support = {SFB 1027//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Adult ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Chelating Agents/pharmacology ; Chitosan/*pharmacology ; Cross-Over Studies ; Dentin/*drug effects ; Humans ; Mouthwashes/*pharmacology ; Saliva/*drug effects/microbiology ; Tannins/*pharmacology ; Young Adult ; }, abstract = {In contrast to enamel, dentin surfaces have been rarely used as substrates for studies evaluating the effects of experimental rinsing solutions on oral biofilm formation. The aim of the present in situ study was to investigate the effects of tannic acid and chitosan on 48-h biofilm formation on dentin surfaces. Biofilm was formed intraorally on dentin specimens, while six subjects rinsed with experimental solutions containing tannic acid, chitosan and water as negative or chlorhexidine as positive control. After 48 h of biofilm formation, specimens were evaluated for biofilm coverage and for viability of bacteria by fluorescence and scanning electron microscopy. In addition, saliva samples were collected after rinsing and analyzed by fluorescence (five subjects) and transmission electron microscopy (two subjects) in order to investigate the antibacterial effect on bacteria in a planktonic state and to visualize effects of the rinsing agents on salivary proteins. After rinsing with water, dentin specimens were covered by a multiple-layered biofilm with predominantly vital bacteria. In contrast, chlorhexidine led to dentin surfaces covered only by few and avital bacteria. By rinsing with tannic acid both strong anti-adherent and antibacterial effects were observed, but the effects declined in a time-dependent manner. Transmission electron micrographs of salivary samples indicated that aggregation of proteins and bacteria might explain the antiadhesion effects of tannic acid. Chitosan showed antibacterial effects on bacteria in saliva, while biofilm viability was only slightly reduced and no effects on bacterial adherence on dentin were observed, despite proteins being aggregated in saliva after rinsing with chitosan. Tannic acid is a promising anti-biofilm agent even on dentin surfaces, while rinsing with chitosan could not sufficiently prevent biofilm formation on dentin.}, } @article {pmid33802293, year = {2021}, author = {Liu, Z and Feng, X and Wang, X and Yang, S and Mao, J and Gong, S}, title = {Quercetin as an Auxiliary Endodontic Irrigant for Root Canal Treatment: Anti-Biofilm and Dentin Collagen-Stabilizing Effects In Vitro.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {5}, pages = {}, pmid = {33802293}, issn = {1996-1944}, support = {81771121//National Natural Science Foundation of China/ ; }, abstract = {Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that does not weaken root canal dentin with commitment anti-biofilm activity and bio-safety. Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. Live and dead bacteria percentages in E. faecalis biofilms were analyzed by confocal laser scanning microscopy (CLSM). Elastic modulus, hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization were tested to evaluate the irrigants' collagen-stabilizing effect. The cytotoxicity was tested by CCK-8 assay. Quercetin increased the proportion of dead bacteria volumes within E. faecalis and improved the flexural strength of dentin compared to control group (p < 0.05). Quercetin-treated dentin matrix had less elasticity loss and hydroxyproline release after collagenase degradation (p < 0.05). Moreover, quercetin solutions revealed an increase in the C-O peak area under both C1s and O1s narrow-scan spectra of XPS characterization, and no cytotoxicity (p > 0.05). Quercetin exhibited anti-biofilm activity, a collagen-stabilizing effect with cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.}, } @article {pmid33802057, year = {2021}, author = {Oleńska, E and Małek, W and Kotowska, U and Wydrych, J and Polińska, W and Swiecicka, I and Thijs, S and Vangronsveld, J}, title = {Exopolysaccharide Carbohydrate Structure and Biofilm Formation by Rhizobium leguminosarum bv. trifolii Strains Inhabiting Nodules of Trifoliumrepens Growing on an Old Zn-Pb-Cd-Polluted Waste Heap Area.}, journal = {International journal of molecular sciences}, volume = {22}, number = {6}, pages = {}, pmid = {33802057}, issn = {1422-0067}, support = {bailout for University of Bialystok (E.O.)//Ministerstwo Nauki i Szkolnictwa Wyższego/ ; 08M03VGRJ//UHasselt Methusalem project/ ; }, mesh = {*Biofilms/drug effects/growth & development ; Metals, Heavy/*metabolism ; Polysaccharides, Bacterial/*metabolism ; Rhizobium leguminosarum/*physiology ; Soil Pollutants/*metabolism ; Trifolium/*microbiology ; }, abstract = {Heavy metals polluting the 100-year-old waste heap in Bolesław (Poland) are acting as a natural selection factor and may contribute to adaptations of organisms living in this area, including Trifolium repens and its root nodule microsymbionts-rhizobia. Exopolysaccharides (EPS), exuded extracellularly and associated with bacterial cell walls, possess variable structures depending on environmental conditions; they can bind metals and are involved in biofilm formation. In order to examine the effects of long-term exposure to metal pollution on EPS structure and biofilm formation of rhizobia, Rhizobium leguminosarum bv. trifolii strains originating from the waste heap area and a non-polluted reference site were investigated for the characteristics of the sugar fraction of their EPS using gas chromatography mass-spectrometry and also for biofilm formation and structural characteristics using confocal laser scanning microscopy under control conditions as well as when exposed to toxic concentrations of zinc, lead, and cadmium. Significant differences in EPS structure, biofilm thickness, and ratio of living/dead bacteria in the biofilm were found between strains originating from the waste heap and from the reference site, both without exposure to metals and under metal exposure. Received results indicate that studied rhizobia can be assumed as potentially useful in remediation processes.}, } @article {pmid33801971, year = {2021}, author = {Yamamoto, K and Kusada, H and Kamagata, Y and Tamaki, H}, title = {Parallel Evolution of Enhanced Biofilm Formation and Phage-Resistance in Pseudomonas aeruginosa during Adaptation Process in Spatially Heterogeneous Environments.}, journal = {Microorganisms}, volume = {9}, number = {3}, pages = {}, pmid = {33801971}, issn = {2076-2607}, support = {259268//Japan Society for the Promotion of Science/ ; JPMJER1502//Japan Science and Technology Agency/ ; }, abstract = {An opportunistic pathogen Pseudomonas aeruginosa has a versatile phenotype and high evolutionary potential to adapt to various natural habitats. As the organism normally lives in spatially heterogeneous and polymicrobial environments from open fields to the inside of hosts, adaptation to abiotic (spatial heterogeneity) and biotic factors (interspecies interactions) is a key process to proliferate. However, our knowledge about the adaptation process of P. aeruginosa in spatially heterogeneous environments associated with other species is limited. We show herein that the evolutionary dynamics of P. aeruginosa PAO1 in spatially heterogeneous environments with Staphylococcus aureus known to coexist in vivo is dictated by two distinct core evolutionary trajectories: (i) the increase of biofilm formation and (ii) the resistance to infection by a filamentous phage which is retained in the PAO1 genome. Hyperbiofilm and/or pili-deficient phage-resistant variants were frequently selected in the laboratory evolution experiment, indicating that these are key adaptive traits under spatially structured conditions. On the other hand, the presence of S. aureus had only a marginal effect on the emergence and maintenance of these variants. These results show key adaptive traits of P. aeruginosa and indicate the strong selection pressure conferred by spatial heterogeneity, which might overwhelm the effect of interspecies interactions.}, } @article {pmid33800098, year = {2021}, author = {Marek, A and Pyzik, E and Stępień-Pyśniak, D and Dec, M and Jarosz, ŁS and Nowaczek, A and Sulikowska, M}, title = {Biofilm-Formation Ability and the Presence of Adhesion Genes in Coagulase-Negative Staphylococci Isolates from Chicken Broilers.}, journal = {Animals : an open access journal from MDPI}, volume = {11}, number = {3}, pages = {}, pmid = {33800098}, issn = {2076-2615}, abstract = {The aim of the study was to analyze the biofilm-production capacity of 87 coagulase-negative Staphylococcus strains (CoNS) isolated from broiler chickens and to determine the occurrence of biofilm-associated genes. The biofilm production capacity of staphylococci was assessed using the microtiter plate method (MTP), and the frequency of genes was determined by PCR. The ability to form a biofilm in vitro was shown in 79.3% of examined strains. Strong biofilm capacity was demonstrated in 26.4% of strains, moderate capacity in 25.3%, weak capacity in 27.6%, and a complete lack of biofilm production capacity in 20.7% of strains. The icaAB gene responsible for the production of extracellular polysaccharide adhesins was detected in 6.9% of strains. The other four genes, i.e., bap (encoding biofilm-associated protein), atlE (encoding cell surface protein exhibiting vitronectin-binding activity), fbe (encoding fibrinogen-binding protein), and eno (encoding laminin-binding protein) were detected in 5.7%, 19.5%, 8%, and 70.1% of strains, respectively. Demonstration of genes that play a role in bacterial biofilm formation may serve as a genetic basis to distinguish between symbiotic and potentially invasive coagulase-negative staphylococcal strains.}, } @article {pmid33800040, year = {2021}, author = {Oh, HK and Hwang, YJ and Hong, HW and Myung, H}, title = {Comparison of Enterococcus faecalis Biofilm Removal Efficiency among Bacteriophage PBEF129, Its Endolysin, and Cefotaxime.}, journal = {Viruses}, volume = {13}, number = {3}, pages = {}, pmid = {33800040}, issn = {1999-4915}, mesh = {*Bacteriophages/metabolism/pathogenicity ; Biofilms/*growth & development ; Endopeptidases/*pharmacology ; *Enterococcus faecalis/growth & development/virology ; Gram-Positive Bacterial Infections/*virology ; Host Specificity ; }, abstract = {Enterococcus faecalis is a Gram-positive pathogen which colonizes human intestinal surfaces, forming biofilms, and demonstrates a high resistance to many antibiotics. Especially, antibiotics are less effective for eradicating biofilms and better alternatives are needed. In this study, we have isolated and characterized a bacteriophage, PBEF129, infecting E. faecalis. PBEF129 infected a variety of strains of E. faecalis, including those exhibiting antibiotic resistance. Its genome is a linear double-stranded DNA, 144,230 base pairs in length. Its GC content is 35.9%. The closest genomic DNA sequence was found in Enterococcus phage vB_EfaM_Ef2.3, with a sequence identity of 99.06% over 95% query coverage. Furthermore, 75 open reading frames (ORFs) were functionally annotated and five tRNA-encoding genes were found. ORF 6 was annotated as a phage endolysin having an L-acetylmuramoyl-l-alanine amidase activity. We purified the enzyme as a recombinant protein and confirmed its enzymatic activity. The endolysin's host range was observed to be wider than its parent phage PBEF129. When applied to bacterial biofilm on the surface of in vitro cultured human intestinal cells, it demonstrated a removal efficacy of the same degree as cefotaxime, but much lower than its parent bacteriophage.}, } @article {pmid33799078, year = {2021}, author = {Ramalingam, B and Venkatachalam, SS and Kiran, MS and Das, SK}, title = {Rationally designed Shewanella oneidensis Biofilm Toilored Graphene-Magnetite Hybrid Nanobiocomposite as Reusable Living Functional Nanomaterial for Effective Removal of Trivalent Chromium.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {278}, number = {}, pages = {116847}, doi = {10.1016/j.envpol.2021.116847}, pmid = {33799078}, issn = {1873-6424}, mesh = {Adsorption ; Biofilms ; Chromium/analysis ; Ferrosoferric Oxide ; *Graphite ; Hydrogen-Ion Concentration ; Shewanella ; *Water Pollutants, Chemical/analysis ; }, abstract = {Sustainable treatment of wastewater containing trivalent chromium (Cr[3+]) remains a significant challenge owing to the several limitations of the existing methodologies. Herein, combination of biosynthesis and Response Surface Methodology (RSM) for the fabrication and optimization of Shewanella oneidensis biofilm functionalized graphene-magnetite (GrM) nanobiocomposite was adopted as a 'living functional nanomaterial' (viz. S-GrM) for effective removal of Cr[3+] ions from aqueous solution. In the biosynthetic process, S. oneidensis cells reduced the GO-akaganeite complex and adhered on the as-synthesized GrM nanocomposite to form S-GrM hybrid-nanobiocomposite. The process parameters for fabrication of S-GrM hybrid-nanobiocomposite was optimized by RSM based on four responses of easy magnetic separation, biofilm formation along with protein, and carbohydrate contents in extracellular polymeric substances (EPS). The morphology and chemical composition of S-GrM hybrid-nanobiocomposite were investigated using various spectroscopic and microscopic analyses and subsequently explored for removal of Cr[3+] ions. The hybrid-nanobiocomposite effectively removed 304.64 ± 14.02 mg/g of Cr[3+] at pH 7.0 and 30 °C, which is found to be very high compared to the previously reported values. The high surface area of graphene, biofilm biomass of S. oneidensis and plenty of functional groups provided a unique structure to the S-GrM hybrid-nanobiocomposite for efficient removal of Cr[3+] through synergistic interaction. The FTIR and zeta potential studies confirmed that electrostatic and chelation/complexation reaction played key roles in the adsorption process. The fabrication of S-GrM nanobiocomposite thus creates a novel hybrid 'living functional nanomaterial' for low cost, recyclable, and sustainable removal of Cr[3+] from wastewater.}, } @article {pmid33798853, year = {2021}, author = {Wang, R and Xu, Q and Chen, C and Li, X and Zhang, C and Zhang, D}, title = {Microbial nitrogen removal in synthetic aquaculture wastewater by fixed-bed baffled reactors packed with different biofilm carrier materials.}, journal = {Bioresource technology}, volume = {331}, number = {}, pages = {125045}, doi = {10.1016/j.biortech.2021.125045}, pmid = {33798853}, issn = {1873-2976}, mesh = {Aquaculture ; Biofilms ; Bioreactors ; Denitrification ; Nitrification ; *Nitrogen ; *Wastewater ; }, abstract = {Fixed-bed baffled reactors packed with carbon fiber (CFBR), polyurethane, or non-woven fabrics were developed to support microbial nitrification-denitrification reactions for nitrogen removal from synthetic aquaculture wastewater. The CFBR showed the best performance, with a short hydraulic retention time and low C/N ratio. Microbial communities in the reactor's biofilms and deposited sludge were analyzed using high-throughput sequencing and quantitative polymerase chain reactions. The biofilms efficiently enriched the nitrifying and denitrifying bacteria in the CFBR. Moreover, bacteria capable of denitrification under aerobic conditions were detected in the aerobic chamber biofilm, showing positive correlations with the main nitrifiers and denitrifiers, which provides potential synergistic interactions for simultaneous nitrification-denitrification in the aerobic chamber. A network analysis revealed that the CFBR had more complex cooperative interactions than others. This study provides insights into the influence of different carrier materials on biofilm formation, proving that the CFBR has potential applications in aquaculture wastewater treatment.}, } @article {pmid33797829, year = {2021}, author = {Ferguson, RMW and O'Gorman, EJ and McElroy, DJ and McKew, BA and Coleman, RA and Emmerson, MC and Dumbrell, AJ}, title = {The ecological impacts of multiple environmental stressors on coastal biofilm bacteria.}, journal = {Global change biology}, volume = {27}, number = {13}, pages = {3166-3178}, doi = {10.1111/gcb.15626}, pmid = {33797829}, issn = {1365-2486}, mesh = {Bacteria ; Biofilms ; Climate Change ; *Ecosystem ; Food Chain ; Humans ; *Microbiota ; }, abstract = {Ecological communities are increasingly exposed to multiple interacting stressors. For example, warming directly affects the physiology of organisms, eutrophication stimulates the base of the food web, and harvesting larger organisms for human consumption dampens top-down control. These stressors often combine in the natural environment with unpredictable results. Bacterial communities in coastal ecosystems underpin marine food webs and provide many important ecosystem services (e.g. nutrient cycling and carbon fixation). Yet, how microbial communities will respond to a changing climate remains uncertain. Thus, we used marine mesocosms to examine the impacts of warming, nutrient enrichment, and altered top-predator population size structure (common shore crab) on coastal microbial biofilm communities in a crossed experimental design. Warming increased bacterial α-diversity (18% increase in species richness and 67% increase in evenness), but this was countered by a decrease in α-diversity with nutrient enrichment (14% and 21% decrease for species richness and evenness, respectively). Thus, we show some effects of these stressors could cancel each other out under climate change scenarios. Warming and top-predator population size structure both affected bacterial biofilm community composition, with warming increasing the abundance of bacteria capable of increased mineralization of dissolved and particulate organic matter, such as Flavobacteriia, Sphingobacteriia, and Cytophagia. However, the community shifts observed with warming depended on top-predator population size structure, with Sphingobacteriia increasing with smaller crabs and Cytophagia increasing with larger crabs. These changes could alter the balance between mineralization and carbon sequestration in coastal ecosystems, leading to a positive feedback loop between warming and CO2 production. Our results highlight the potential for warming to disrupt microbial communities and biogeochemical cycling in coastal ecosystems, and the importance of studying these effects in combination with other environmental stressors.}, } @article {pmid33796615, year = {2021}, author = {Sahal, G and Woerdenbag, HJ and Hinrichs, WLJ and Visser, A and van der Mei, HC and Bilkay, IS}, title = {Candida Biofilm Formation Assay on Essential Oil Coated Silicone Rubber.}, journal = {Bio-protocol}, volume = {11}, number = {5}, pages = {e3941}, pmid = {33796615}, issn = {2331-8325}, abstract = {Development of biofilm associated candidemia for patients with implanted biomaterials causes an urgency to develop antimicrobial and biofilm inhibitive coatings in the management of recalcitrant Candida infections. Recently, there is an increase in the number of patients with biofilm formation and resistance to antifungal therapy. Therefore, there is a growing interest to use essential oils as coating agents in order to prevent biomaterial-associated Candida infections. Often high costs, complicated and laborious technologies are used for both applying the coating and determination of the antibiofilm effects hampering a rapid screening of essential oils. In order to determine biofilm formation of Candida on essential oil coated surfaces easier, cheaper and faster, we developed an essential oil (lemongrass oil) coated surface (silicone-rubber) by using a hypromellose ointment/essential oil mixture. Furthermore, we modified the "crystal violet binding assay" to quantify the biofilm mass of Candida biofilm formed on the lemongrass oil coated silicone rubber surface. The essential oil coating and the biomass determination of biofilms on silicone rubber can be easily applied with simple and accessible equipment, and will therefore provide rapid information about whether or not a particular essential oil is antiseptic, also when it is used as a coating agent.}, } @article {pmid33794846, year = {2021}, author = {Kommerein, N and Weigel, AJ and Stiesch, M and Doll, K}, title = {Plant-based oral care product exhibits antibacterial effects on different stages of oral multispecies biofilm development in vitro.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {170}, pmid = {33794846}, issn = {1472-6831}, mesh = {*Actinomyces ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Veillonella ; }, abstract = {BACKGROUND: Excessive biofilm formation on surfaces in the oral cavity is amongst the main reasons for severe infection development like periodontitis and peri-implantitis. Mechanical biofilm removal as well as the use of adjuvant antiseptics supports the prevention of pathogenic biofilm formation. Recently, the antibacterial effect of the oral care product REPHA-OS[®], based on medicinal plant extracts and essential oils, has been demonstrated on oral pathogens grown on agar plates. In the present study, the effectiveness of the product on medical relevant oral biofilm development should be demonstrated for the first time.

METHODS: An established in vitro oral multispecies biofilm, composed of Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis, was used to analyze the antibacterial effect of different REPHA-OS[®] concentrations on planktonic bacteria, biofilm formation and mature biofilms. It was quantified using metabolic activity assays and live/dead fluorescence staining combined with three-dimensional confocal laser-scanning microscopy. Additionally, effects on species distribution inside the biofilm were assessed by means of quantitative real-time PCR.

RESULTS: REPHA-OS[®] showed statistically significant antimicrobial effects on all stages of biofilm development: a minimal inhibitory concentration of 5% could be detected for both, for planktonic bacteria and for biofilm formation. Interestingly, only a slightly higher concentration of 10% was necessary to completely kill all bacteria in mature biofilms also. In contrast, an influence on the biofilm matrix or the species distribution could not be observed. The effect could be attributed to the herbal ingredients, not to the contained ethanol.

CONCLUSION: The strong antibacterial effect of REPHA-OS[®] on different stages of oral biofilm development strengthens its application as an alternative adjuvant in oral care therapies.}, } @article {pmid33794333, year = {2021}, author = {Passos, MR and Almeida, RS and Lima, BO and Rodrigues, JZS and Macêdo Neres, NS and Pita, LS and Marinho, PDF and Santos, IA and da Silva, JP and Oliveira, MC and Oliveira, MA and Pessoa, SMB and Silva, MML and Silveira, PHS and Reis, MM and Santos, IP and Ricardo, LON and Andrade, LOSB and Soares, AB and Correia, TML and Souza, ÉP and Pires, PN and Cruz, MP and Marques, LM and Uetanabaro, APT and Yatsuda, R}, title = {Anticariogenic activities of Libidibia ferrea, gallic acid and ethyl gallate against Streptococcus mutans in biofilm model.}, journal = {Journal of ethnopharmacology}, volume = {274}, number = {}, pages = {114059}, doi = {10.1016/j.jep.2021.114059}, pmid = {33794333}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/growth & development ; Dental Caries/prevention & control ; *Fabaceae ; Fruit ; Gallic Acid/*analogs & derivatives/analysis/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Glucosyltransferases/genetics ; Phytochemicals/analysis/pharmacology ; Plant Extracts/chemistry/*pharmacology ; Seeds ; Streptococcus mutans/*drug effects/genetics/physiology ; }, abstract = {In Brazil, ethnopharmacological studies show that Libidibia ferrea (Mart. ex Tul.) L. P. Queiroz is commonly used in folk medicine as an antifungal, antimicrobial and anti-inflammatory. In the Amazon region, the dried fruit powder of L. ferrea are widely used empirically by the population in an alcoholic tincture as an antimicrobial mouthwash in oral infections and the infusion is also recommended for healing oral wounds. However, there are few articles that have evaluated the antimicrobial activity against oral pathogens in a biofilm model, identifying active compounds and mechanisms of action.

AIM OF THE STUDY: The aim of this study was to evaluate the antimicrobial and anti-adherence activities of the ethanolic extract, fractions and isolated compounds (gallic acid and ethyl gallate) of the fruit and seed of L. ferrea against Streptococcus mutans. The inhibition of acidicity/acidogenicity and the expression of the S. mutans GTF genes in biofilms were also evaluated.

MATERIALS AND METHODS: Minimal Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration of Cell Adhesion (MICA) were evaluated with ethanolic extract (EELF), fractions, gallic acid (GA) and ethyl gallate (EG) against S. mutans. Inhibition of biofilm formation, pH drop and proton permeability tests were conducted with EELF, GA and EG, and also evaluated the expression of the GTF genes in biofilms. The compounds of dichloromethane fraction were identified by GC-MS.

RESULTS: This is the first report of shikimic, pyroglutamic, malic and protocatechuic acids identified in L. ferrea. EELF, GA and EG showed MIC at 250 μg/mL, and MBC at 1000 μg/mL by EELF. EELF biofilms showed reduced dry weight and acidogenicity of S. mutans in biofilms. GA and EG reduced viable cells, glucans soluble in alkali, acidogenicity, aciduricity and downregulated expression of gtfB, gtfC and gtfD genes in biofilms. SEM images of GA and EG biofilms showed a reduction of biomass, exopolysaccharide and microcolonies of S. mutans.

CONCLUSIONS: The ethanolic extract of fruit and seed of L. ferrea, gallic acid and ethyl gallate showed great antimicrobial activity and inhibition of adhesion, reduction of acidogenicity and aciduricity in S. mutans biofilms. The results obtained in vitro validate the use of this plant in ethnopharmacology, and open opportunities for the development of new oral anticariogenic agents, originated by plants that can inhibit pathogenic biofilm that leads to the development of caries.}, } @article {pmid33790586, year = {2021}, author = {Senobar Tahaei, SA and Stájer, A and Barrak, I and Ostorházi, E and Szabó, D and Gajdács, M}, title = {Correlation Between Biofilm-Formation and the Antibiotic Resistant Phenotype in Staphylococcus aureus Isolates: A Laboratory-Based Study in Hungary and a Review of the Literature.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {1155-1168}, pmid = {33790586}, issn = {1178-6973}, abstract = {INTRODUCTION: Staphylococcus aureus (S. aureus) is an important causative pathogen in human infections. The production of biofilms by bacteria is an important factor, leading to treatment failures. There has been significant interest in assessing the possible relationship between the multidrug-resistant (MDR) status and the biofilm-producer phenotype in bacteria. The aim of our present study was to assess the biofilm-production rates in clinical methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA] isolates from Hungarian hospitals and the correlation between resistance characteristics and their biofilm-forming capacity.

METHODS: A total of three hundred (n=300) S. aureus isolates (corresponding to MSSA and MRSA isolates in equal measure) were included in this study. Identification of the isolates was carried out using the VITEK 2 ID/AST system and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests, confirmation of MRSA status was carried out using PBP2a agglutination assay. Biofilm-production was assessed using the crystal violet (CV) tube-adherence method and the Congo red agar (CRA) plate method.

RESULTS: There were significant differences among MSSA and MRSA isolates regarding susceptibility-levels to commonly used antibiotics (in case of erythromycin, clindamycin and ciprofloxacin: p<0.001, gentamicin: p=0.023, sulfamethoxazole/trimethoprim: p=0.027, rifampin: p=0.037). In the CV tube adherence-assay, 37% (n=56) of MSSA and 39% (n=58) of MRSA isolates were positive for biofilm-production, while during the use of CRA plates, 41% (n=61) of MSSA and 44% (n=66) of MRSA were positive; no associations were found between methicillin-resistance and biofilm-production. On the other hand, erythromycin, clindamycin and rifampin resistance was associated with biofilm-positivity (p=0.004, p<0.001 and p<0.001, respectively). Biofilm-positive isolates were most common from catheter-associated infections.

DISCUSSION: Our study emphasizes the need for additional experiments to assess the role biofilms have in the pathogenesis of implant-associated and chronic S. aureus infections.}, } @article {pmid33785834, year = {2021}, author = {Zhang, S and Wang, P and Shi, X and Tan, H}, title = {Inhibitory properties of Chinese Herbal Formula SanHuang decoction on biofilm formation by antibiotic-resistant Staphylococcal strains.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {7134}, pmid = {33785834}, issn = {2045-2322}, mesh = {Biofilms/drug effects ; Drugs, Chinese Herbal/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Staphylococcus epidermidis/*drug effects ; }, abstract = {The aim of this study was to explore the effect of Chinese herbal SanHuang decoction (SH) on biofilm formation of antibiotic-resistant Staphylococci on titanium surface, and to explore its mechanism. Biofilm-forming ATCC 35984, ATCC 43300 and MRSE 287 were used in this study. The MICs of SH and vancomycin against Staphylococci were determined by the broth microdilution method. Six groups were designed, namely control group (bacteria cultured with medium), 1/8MIC SH group (1MIC SH was diluted by 1/8 using TSB or saline), 1/4MIC SH group, 1/2MIC SH group, 1MIC SH group and vancomycin group (bacteria cultured with 1MIC vancomycin). The inhibitory effect on bacterial adhesion and biofilm formation were observed by the spread plate method, CV staining, SEM, and CLSM. Real-time PCR was performed to determine the effect of SH on the expression levels of ica AD and ica R gene in ATCC 35984 during the biofilm formation. The strains were found to be susceptible to SH and vancomycin with MIC of 38.75 mg/ml and 2.5 μg/ml, respectively. SH with 1 MIC and 1/2 MIC could inhibit the bacteria adhesion, showing only scattered adhesion from SEM. CLSM showed that SH with 1 MIC and 1/2 MIC inhibited the biofilm formation. The quantitative results of the spread plate method and CV staining showed that there was significant differences between the SH groups (P < 0.05). Further, with an increase in SH concentration, the inhibitory effect became more obvious when compared with control group. Among the groups, vancomycin had the strongest inhibitory effect on bacterial adhesion and biofilm formation (P < 0.01). With an increase in SH concentration, the expression levels of ica AD decreased, and the expression of ica R increased correspondingly (P < 0.05). In conclusions, SH can inhibit the biofilm formation of antibiotic-resistant Staphylococci. Its probable mechanistic activity may be through the inhibition of polysaccharide intercellular adhesin synthesis by down-regulating the expression of ica AD gene.}, } @article {pmid33784393, year = {2021}, author = {Faria, SI and Teixeira-Santos, R and Morais, J and Vasconcelos, V and Mergulhão, FJ}, title = {The association between initial adhesion and cyanobacterial biofilm development.}, journal = {FEMS microbiology ecology}, volume = {97}, number = {5}, pages = {}, doi = {10.1093/femsec/fiab052}, pmid = {33784393}, issn = {1574-6941}, mesh = {Bacterial Adhesion ; *Biofilms ; Chlorophyll A ; *Cyanobacteria ; Polymers ; }, abstract = {Although laboratory assays provide valuable information about the antifouling effectiveness of marine surfaces and the dynamics of biofilm formation, they may be laborious and time-consuming. This study aimed to determine the potential of short-time adhesion assays to estimate how biofilm development may proceed. The initial adhesion and cyanobacterial biofilm formation were evaluated using glass and polymer epoxy resin surfaces under different hydrodynamic conditions and were compared using linear regression models. For initial adhesion, the polymer epoxy resin surface was significantly associated with a lower number of adhered cells compared with glass (-1.27 × 105 cells.cm-2). Likewise, the number of adhered cells was significantly lower (-1.16 × 105 cells.cm-2) at 185 than at 40 rpm. This tendency was maintained during biofilm development and was supported by the biofilm wet weight, thickness, chlorophyll a content and structure. Results indicated a significant correlation between the number of adhered and biofilm cells (r = 0.800, p < 0.001). Moreover, the number of biofilm cells on day 42 was dependent on the number of adhered cells at the end of the initial adhesion and hydrodynamic conditions (R2 = 0.795, p < 0.001). These findings demonstrate the high potential of initial adhesion assays to estimate marine biofilm development.}, } @article {pmid33783975, year = {2021}, author = {Gao, L and Liu, X and Xu, M and Sun, G and Xu, S and Zou, T and Wang, L and Wang, F and Da, J and Wang, Y and Wang, L}, title = {Biodegradable Anti-Biofilm Fiber-Membrane Ureteral Stent Constructed with a Robust Biomimetic Superhydrophilic Polycationic Hydration Surface Exhibiting Synergetic Antibacterial and Antiprotein Properties.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {17}, number = {20}, pages = {e2006815}, doi = {10.1002/smll.202006815}, pmid = {33783975}, issn = {1613-6829}, mesh = {Anti-Bacterial Agents/pharmacology ; Biomimetics ; *Escherichia coli ; Humans ; *Staphylococcus aureus ; Stents ; Surface Properties ; }, abstract = {The biofouling of ureteral stents and subsequent urinary tract infections mainly come from the adsorption and adhesion of proteins and microorganisms and their ensuing proliferation. Although general polycationic surfaces in implants have good antibacterial activities, they suffer from limited durability due to severe protein and bacterial adsorption. Here, a biodegradable and anti-biofilm fiber-membrane structured ureteral stent (FMBUS) with synergetic contact-killing antibacterial activity and antiprotein adsorption is described. The stent is prepared by generating hyperbranched poly(amide-amine)-grafted polydopamine microparticles (≈300 nm) on the surface of fibers by in situ polymerization and Schiff base reactions. The biomimetic surface endows the FMBUS with a positive charge (+21.36 mV) and superhydrophilicity (water contact angle: 0°). As a result, the stents fulfilled the following functions: i) reduced attachment of host protein due to superhydrophilicity (Lysozyme: 92.1%; human serum albumin: 39.4%); ii) high bactericidal activities against contact pathogenic bacteria (contact-killing rate: 99.9999% for both E. coli and S. aureus; antiadhesion rate: 99.2% for E. coli and 99.9999% for S. aureus); iii) biocompatibility in vitro (relative growth rate of L929: >90% on day 3) and in vivo; and iv) gradient biodegradability to avoid a second surgery of stent extraction 1-2 weeks after implantation.}, } @article {pmid33783720, year = {2021}, author = {Chandla, S and Harjai, K and Shukla, G}, title = {Synergistic Effect of Biogenics Derived from Potential Probiotics Together with Zingerone Against Biofilm Formation by Pseudomonas aeruginosa PAO1.}, journal = {Probiotics and antimicrobial proteins}, volume = {13}, number = {5}, pages = {1481-1497}, pmid = {33783720}, issn = {1867-1314}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/drug effects ; Biological Products/*pharmacology ; Guaiacol/*analogs & derivatives/pharmacology ; *Probiotics ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {Biogenics are compounds produced by living organisms such as animals, plants, bacteria, etc. Probiotics and their biogenics are known for their antimicrobial potential. Therefore, the present study was designed to evaluate the antibiofilm potential of probiotic-derived biogenics in conjunction with zingerone against the Pseudomonas aeruginosa PAO1 biofilm. Cell-free supernatant (CFS) of potential probiotics Pediococcus acidilactici BNS5B and Lactobacillus fermentum PUM was found to inhibit the growth of Ps. aeruginosa PAO1 maximally among the nineteen isolated lactic acid bacteria. L. fermentum PUM produced precipitated protein fraction (PP), organic acids (OAs), exopolysaccharides (EPSs), biosurfactants (BSs) and various volatile antimicrobial compounds, while Ped. acidilactici BNS5B was found to produce PP, OA, EPS, BS and fewer volatile antimicrobial compounds only. More specifically, CFS and selected biogenics (OA and PP from L. fermentum PUM; OA from Ped. acidilactici BNS5B) of both potential probiotics showed synergy with zingerone against Ps. aeruginosa growth as observed by FIC index (< 0.5). Interestingly, CFS of both potential probiotics in combination with zingerone led to the formation of a more distorted biofilm compared with OA of L. fermentum PUM and zingerone, OA of Ped. acidilactici BNS5B and zingerone, PP of L. fermentum PUM and zingerone as well as their individual counterparts. Similarly, both confocal laser scanning microscopy and XTT assay showed an increased number of dead and impaired cells along with the decreased viability of biofilm cells. Thus, it can be reckoned that a combination of probiotic-derived biogenics and zingerone can have therapeutic application against Ps. aeruginosa infections which needs to be validated clinically.}, } @article {pmid33783274, year = {2021}, author = {Alhobeira, HA and Al Mogbel, M and Khan, S and Khan, M and Haque, S and Somvanshi, P and Wahid, M and Mandal, RK}, title = {Prioritization and characterization of validated biofilm blockers targeting glucosyltransferase C of Streptococcus mutans.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {49}, number = {1}, pages = {335-344}, doi = {10.1080/21691401.2021.1903021}, pmid = {33783274}, issn = {2169-141X}, mesh = {Biofilms/*drug effects ; Dental Caries/microbiology ; Glucosyltransferases/*metabolism ; Streptococcus mutans/*drug effects/*physiology ; }, abstract = {To date, several Glucosyltransferase C (GtfC) inhibitors have been identified and experimentally validated. All these inhibitors have been validated at different experimental conditions like degree of purity, animal models, kinetic conditions, experimental environment etc.; and most of these inhibitors (ligands) proved to be quite effective in their respective validation environment. However, due to varied experimental validation conditions, and absence of molecular interaction data, there is no way to prioritize these validated ligands for their inhibition potential against GtfC. The present study is a novel attempt of comparative evaluation of the interaction of the validated ligands on a single platform and under similar conditions with a dual objective, i.e. ligand prioritization for their respective inhibitory potential and elucidation of the involved unknown molecular interactions. Carbohydrate derivatives (6-Deoxy sucrose and Trichloro-galactosucrose) were identified as the most promising GtfC inhibitors. In addition, Asp588, Trp517, and Asn481 amino acid residues of the domain A1 proved vital for the inhibitory effect. The study highlights the importance of the comparative analysis of the validated ligands in order to identify the most promising leads for drug discovery against dental caries.}, } @article {pmid33781179, year = {2021}, author = {Chen, X and Ma, J}, title = {Weighted gene co-expression network analysis (WGCNA) to explore genes responsive to Streptococcus oralis biofilm and immune infiltration analysis in human gingival fibroblasts cells.}, journal = {Bioengineered}, volume = {12}, number = {1}, pages = {1054-1065}, pmid = {33781179}, issn = {2165-5987}, mesh = {*Biofilms ; Fibroblasts/*immunology/*microbiology ; *Gene Expression Regulation ; *Gene Regulatory Networks ; Gingiva/*pathology ; Humans ; Macrophages/metabolism ; Protein Interaction Maps/genetics ; Streptococcus oralis/*physiology ; }, abstract = {The correlation between oral bacteria and dental implants failure has been reported. However, the effect and mechanism of bacteria during dental implants is unclear. In this study, we explored key genes and candidate gene clusters in human gingival fibroblasts (HGF) cells in response to Streptococcus oralis biofilm through weighted gene co-expression network analysis (WGCNA) and differential genes analysis using gene expression matrix, GSE134481, downloaded from the Gene Expression Omnibus (GEO) database. We obtained 325 genes in the module significantly associated with S. oralis infection and 113 differentially expressed genes (DEGs) in the S. oralis biofilm; 62 DEGs indicated significant correlation with S. oralis injury. Multiple immune pathways, such as the tumor necrosis factor (TNF) signaling pathway, were considerably enriched. We obtained a candidate genes cluster containing 12 genes - IL6, JUN, FOS, CSF2, HBEGF, EDN1, CCL2, MYC, NGF, SOCS3, CXCL1, and CXCL2; we observed 5 candidate hub genes associated with S. oralis infection - JUN, IL6, FOS, MYC, and CCL2. The fraction of macrophage M0 cells was significantly increased in biofilm treatment compared with control; expression of FOS and MYC was significantly positively correlated with macrophage M0 cells. Our findings present a fierce inflammation changes in the transcript level of HGF in response to S. oralis.}, } @article {pmid33780904, year = {2021}, author = {Stuermer, EK and Besser, M and Brill, F and Geffken, M and Plattfaut, I and Severing, AL and Wiencke, V and Rembe, JD and Naumova, EA and Kampe, A and Debus, S and Smeets, R}, title = {Comparative analysis of biofilm models to determine the efficacy of antimicrobials.}, journal = {International journal of hygiene and environmental health}, volume = {234}, number = {}, pages = {113744}, doi = {10.1016/j.ijheh.2021.113744}, pmid = {33780904}, issn = {1618-131X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Pseudomonas aeruginosa ; Sheep ; *Staphylococcus aureus ; }, abstract = {Biofilms are one of the greatest challenges in today's treatment of chronic wounds. While antimicrobials kill platonic bacteria within seconds, they are rarely able to harm biofilms. In order to identify effective substances for antibacterial therapy, cost-efficient, standardized and reproducible models that aim to mimic the clinical situation are required. In this study, two 3D biofilm models based on human plasma with immune cells (lhBIOM) or based on sheep blood (sbBIOM) containing S. aureus or P. aeruginosa, are compared with the human biofilm model hpBIOM regarding their microscopic structure (scanning electron microscopy; SEM) and their bacterial resistance to octenidine hydrochloride (OCT) and a sodium hypochlorite (NaOCl) wound-irrigation solution. The three analyzed biofilm models show little to no reaction to treatment with the hypochlorous solution while planktonic S. aureus and P. aeruginosa cells are reduced within minutes. After 48 h, octenidine hydrochloride manages to erode the biofilm matrix and significantly reduce the bacterial load. The determined effects are qualitatively reflected by SEM. Our results show that both ethically acceptable human and sheep blood based biofilm models can be used as a standard for in vitro testing of new antimicrobial substances. Due to their composition, both fulfill the criteria of a reality-reflecting model and therefore should be used in the approval for new antimicrobial agents.}, } @article {pmid33780232, year = {2021}, author = {Chiolerio, A and Adamatzky, A}, title = {Acetobacter Biofilm: Electronic Characterization and Reactive Transduction of Pressure.}, journal = {ACS biomaterials science & engineering}, volume = {7}, number = {4}, pages = {1651-1662}, pmid = {33780232}, issn = {2373-9878}, mesh = {*Acetobacter ; Biofilms ; Electronics ; *Wearable Electronic Devices ; }, abstract = {The bacterial skin studied here is a several centimeter-wide colony of Acetobacter aceti living on a cellulose-based hydrogel. We demonstrate that the colony exhibits trains of spikes of extracellular electrical potential, with amplitudes of the spikes varying from 1 to 17 mV. The bacterial pad responds to mechanical stimulation with distinctive changes in its electrical activity. While studying the passive electrical properties of the bacterial pad, we found that the pad provides an open-circuit voltage drop (between 7 and 25 mV) and a small short-circuit current (1.5-4 nA). We also observed by pulsed tomography and spatially resolved impedance spectroscopy that the conduction occurs along preferential paths, with the peculiar side-effect of having a higher resistance between closer electrodes. We speculate that the Acetobacter biofilms could be utilized in the development of living skin for soft robots: such skin will act as an electrochemical battery and a reactive tactile sensor. It could even be used for wearable devices.}, } @article {pmid33779527, year = {2022}, author = {Yu, KH and Can, F and Ergenekon, P}, title = {Nitric oxide and nitrite removal by partial denitrifying hollow-fiber membrane biofilm reactor coupled with nitrous oxide generation as energy recovery.}, journal = {Environmental technology}, volume = {43}, number = {19}, pages = {2934-2947}, doi = {10.1080/09593330.2021.1910348}, pmid = {33779527}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; Carbon ; Denitrification ; Nitric Oxide ; *Nitrites ; Nitrogen ; *Nitrous Oxide ; }, abstract = {Nitrogen oxide (NOx) emissions cause significant impacts on the environment and must therefore be controlled even more stringently. This requires the development of cost-effective removal strategies which simultaneously create value-added by-products or energy from the waste. This study aims to treat gaseous nitric oxide (NO) by hollow-fibre membrane biofilm reactor (HFMBfR) in the presence of nitrite (NO2-) and evaluate nitrous oxide (N2O) emissions formed as an intermediate product during the denitrification process. Accumulated N2O can be utilised in methane oxidation as an oxidant to produce energy. In the first stage of the study, the HFMBfR was operated by feeding only gaseous NO as the nitrogen source. During this period, the best performance was achieved with 92% NO removal efficiency (RE). In the second stage, both NO gas and NO2- were supplied to the system, and 91% NO and 99% NO2- reduction were achieved simultaneously with the maximum N2O generation of 386 ± 31 ppm. Lower influent carbon to nitrogen (C/N) ratios, such as 4.5 and 2.0, and higher NO2--N loading rate of 158 mg N day[-1] favoured N2O generation. An improved NO removal rate and N2O accumulation were seen with the increasing amount of PO43- in the medium. The 16S rDNA sequencing analysis revealed that Alicycliphilus denitrificans and Pseudomonas putida were the dominant species. The study shows that an HFMBfR can be successfully used to eliminate both NO2- and gaseous NO and simultaneously generate N2O by adjusting the system parameters such as C/N ratio, NO2- and PO43- loading.}, } @article {pmid33775225, year = {2022}, author = {Decru, SO and Baeten, JE and Cui, YX and Wu, D and Chen, GH and Volcke, EIP}, title = {Model-based analysis of sulfur-based denitrification in a moving bed biofilm reactor.}, journal = {Environmental technology}, volume = {43}, number = {19}, pages = {2948-2955}, doi = {10.1080/09593330.2021.1910349}, pmid = {33775225}, issn = {1479-487X}, mesh = {Bacteria ; *Biofilms ; Bioreactors ; *Denitrification ; Nitrogen ; Sulfides ; Sulfur ; Wastewater ; }, abstract = {In this study, a biofilm model was developed for sulfur-based denitrification in a moving bed biofilm reactor (MBBR), including mass transport as well as the conversion kinetics of sulfur-oxidizing bacteria (SOB). The experimental reactor simulated received a synthetic wastewater containing nitrate, sulfide and thiosulfate. The substrate affinity of SOB for intermediary elemental sulfur (S[0]) was found the most sensitive parameter. After estimating this single parameter, the model could adequately describe the steady state performance of the experimental MBBR. The experimental and simulated mass balances indicated that a fraction of influent sulfur accumulated into intermediate S[0]. Furthermore, the simulations showed that SOB were active over the entire thickness of a 200 µm biofilm. The simulation results allowed to quantify the extent of diffusion and substrate limitation. Scenario analyses indicated that the specific nitrogen loading rate could be increased from 0.05 to 0.20 kg N.kg[-1] VSS.day[-1] (corresponding to 0.22-0.86 kg N.m[-2].day[-1] expressed per biofilm surface area) while maintaining nitrogen removal efficiencies above 70%. An increasing specific nitrogen loading rate in this range resulted in an almost linearly increasing specific nitrogen removal rate, independent from whether it was realized through a decreasing HRT, carrier filling ratio or biofilm thickness.}, } @article {pmid33774716, year = {2021}, author = {Shibli, JA and Rocha, TF and Coelho, F and de Oliveira Capote, TS and Saska, S and Melo, MA and Pingueiro, JMS and de Faveri, M and Bueno-Silva, B}, title = {Metabolic activity of hydro-carbon-oxo-borate on a multispecies subgingival periodontal biofilm: a short communication.}, journal = {Clinical oral investigations}, volume = {25}, number = {10}, pages = {5945-5953}, pmid = {33774716}, issn = {1436-3771}, support = {311368/2019-0//CNPq/ ; }, mesh = {Biofilms ; *Borates/pharmacology ; *Carbon ; Chlorhexidine/pharmacology ; Porphyromonas gingivalis ; }, abstract = {OBJECTIVE: This study evaluated the metabolic activity of hydro-carbon-oxo-borate complex (HCOBc) on a multispecies subgingival biofilm as well as its effects on cytotoxicity.

MATERIALS AND METHODS: The subgingival biofilm with 32 species related to periodontitis was formed in the Calgary Biofilm Device (CBD) for 7 days. Two different therapeutic schemes were adopted: (1) treatment with HCOBc, 0.12% chlorhexidine (CHX), and negative control group (without treatment) from day 3 until day 6, two times a day for 1 min each time, totaling 8 treatments and (2) a 24-h treatment on a biofilm grown for 6 days. After 7 days of formation, biofilm metabolic activity was determined by colorimetry assay, and bacterial counts and proportions of complexes were determined by DNA-DNA hybridization. Both substances' cytotoxicity was evaluated by cell viability (XTT assay) and clonogenic survival assay on ovary epithelial CHO-K1 cells and an osteoblast precursor from calvaria MC3T3-E1 cells.

RESULTS: The first treatment scheme resulted in a significant reduction in biofilm's metabolic activity by means of 77% by HCOBc and CHX treatments versus negative control. The total count of 11 and 25 species were decreased by treatment with hydro-carbon-oxo-borate complex and CHX, respectively, compared with the group without treatment (p < 0.05), highlighting a reduction in the levels of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Fusobacterium periodontium. CHX significantly reduced the count of 10 microorganisms compared to the group treated with HCOBc (p < 0.05). HCOBc and CHX significantly decreased the pathogenic red-complex proportion compared with control-treated biofilm, and HCOBc had even a more significant effect on the red complex than CHX had (p ≤ 0.05). For the second treatment scheme, HCOBc complex and CHX significantly decreased 61 and 72% of control biofilms' metabolic activity and the counts of 27 and 26 species, respectively. HCOBc complex did not significantly affect the proportions of formed biofilms, while CHX significantly reduced red, orange, and yellow complexes. Both substances exhibited similar cytotoxicity results.

CONCLUSIONS: This short communication suggested that the HCOBc complex reduced a smaller number of bacterial species when compared to chlorhexidine during subgingival biofilm formation, but it was better than chlorhexidine in reducing red-complex bacterial proportions. Although HCOBc reduced the mature 6-day-old subgingival multispecies biofilms, it did not modify bacterial complexes' ratios as chlorhexidine did on the biofilms mentioned above. Future in vivo studies are needed to validate these results.

CLINICAL RELEVANCE: HCOBc complex could be used to reduce red-complex periodontal bacterial proportions.}, } @article {pmid33774284, year = {2021}, author = {Yu, N and Guo, B and Liu, Y}, title = {Shaping biofilm microbiomes by changing GAC location during wastewater anaerobic digestion.}, journal = {The Science of the total environment}, volume = {780}, number = {}, pages = {146488}, doi = {10.1016/j.scitotenv.2021.146488}, pmid = {33774284}, issn = {1879-1026}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Charcoal ; Methane ; *Microbiota ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The addition of granular activated carbon (GAC) to up-flow anaerobic sludge blanket (UASB) reactors treating synthetic wastewater enhanced methane production by stimulating direct interspecies electron transfer (DIET). A modified UASB reactor with GAC packed in plastic carriers that allowed the GAC to float in the upper reactor zone achieved enhanced performance compared to a UASB reactor with GAC settled at the bottom of the reactor. Microbial communities in the biofilms developed on settled or floated GAC were compared. Methanosarcina (56.3-73.3%) dominated the floated-GAC biofilm whereas Methanobacterium (84.9-85.1%) was greatly enriched in the settled-GAC biofilm. Methanospirillum and Methanocorpusculum were enriched in the floated-GAC biofilm (8.8-19.8% and 5.1-9.5%, respectively), but only existed in low abundances in the settled-GAC biofilm (3.4-3.6% and 0-0.4%, respectively). The floated GAC developed bacterial communities with higher diversity and more syntrophic bacteria enrichments on its surface, including Geobacter, Smithella, and Syntrophomonas, than the settled-GAC biofilm. Common hydrogen-donating syntrophs and hydrogenotrophic archaea, Methanospirillum and Methanoregula, were identified as potential electro-active microorganisms related to DIET.}, } @article {pmid33773304, year = {2021}, author = {Motiei, A and Ogonowski, M and Reichelt, S and Gorokhova, E}, title = {Ecotoxicological assessment of suspended solids: The importance of biofilm and particle aggregation.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {280}, number = {}, pages = {116888}, doi = {10.1016/j.envpol.2021.116888}, pmid = {33773304}, issn = {1873-6424}, mesh = {Animals ; Biofilms ; Daphnia ; Ecotoxicology ; *Plastics/toxicity ; *Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {Assessment of microplastic impacts in biota is challenging due to the complex behavior of the test particles and their interactions with other particulates, including microorganisms, in the environment. To disentangle responses to microplastic exposure from those to other suspended solids, both microplastic and natural particles must be present in the test system. We evaluated how microplastic, non-plastic particles, and biofilms interacted in their effects on survivorship using acute toxicity assay with Daphnia magna. The animals were exposed to microplastic and kaolin at different concentrations of suspended solids (SS; 10, 100, and 1000 mg/L) with a varying microplastic contribution (%MP; 0-80%) and biofilm (presence/absence) associated with the solids. Also, we examined how these exposure parameters (SS, %MP, and Biofilm) affected aggregate formation that was analyzed using particle size distribution data. Under the exposure conditions, Daphnia mortality was primarily driven by SS concentration but ameliorated by both microplastic and biofilm. The ameliorating effects were related to increased particle aggregation in the presence of biofilm and high %MP. In addition, a weak yet significant positive effect of the biofilm on the survivorship was observed, presumably, due to microbial food supply to the daphniids in the exposure system; the bacteria were utilized at the absence of other food. Therefore, the effects of both natural and anthropogenic particulates depend on the particle behavior and aggregation in the water governed by microbial communities and physicochemical properties of the particles, which must be taken into account in the hazard assessment of plastic litter.}, } @article {pmid33773215, year = {2021}, author = {Poudel, A and Oludiran, A and Sözer, EB and Casciola, M and Purcell, EB and Muratori, C}, title = {Growth in a biofilm sensitizes Cutibacterium acnes to nanosecond pulsed electric fields.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {140}, number = {}, pages = {107797}, doi = {10.1016/j.bioelechem.2021.107797}, pmid = {33773215}, issn = {1878-562X}, mesh = {Acne Vulgaris/microbiology ; *Biofilms ; Electricity ; Electromagnetic Fields ; Electroporation ; Humans ; Microbial Viability ; Propionibacteriaceae/growth & development/*physiology ; Skin/microbiology ; }, abstract = {The Gram-positive anaerobic bacterium Cutibacterium acnes (C. acnes) is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. C. acnes can form biofilms; cells in biofilms are more resilient to antimicrobial stresses. Acne therapeutic options such as topical or systemic antimicrobial treatments often show incomplete responses. In this study we measured the efficacy of nanosecond pulsed electric fields (nsPEF), a new promising cell and tissue ablation technology, to inactivate C. acnes. Our results show that all tested nsPEF doses (250 to 2000 pulses, 280 ns pulses, 28 kV/cm, 5 Hz; 0.5 to 4 kJ/ml) failed to inactivate planktonic C. acnes and that pretreatment with lysozyme, a naturally occurring cell-wall-weakening enzyme, increased C. acnes vulnerability to nsPEF. Surprisingly, growth in a biofilm appears to sensitize C. acnes to nsPEF-induced stress, as C. acnes biofilm-derived cells showed increased cell death after nsPEF treatments that did not affect planktonic cells. Biofilm inactivation by nsPEF was confirmed by treating intact biofilms grown on glass coverslips with an indium oxide conductive layer. Altogether our results show that, contrary to other antimicrobial agents, nsPEF kill more efficiently bacteria in biofilms than planktonic cells.}, } @article {pmid33772618, year = {2021}, author = {Gupta, S and Gupta, P and Pruthi, V}, title = {Impact of Bacillus licheniformis SV1 Derived Glycolipid on Candida glabrata Biofilm.}, journal = {Current microbiology}, volume = {78}, number = {5}, pages = {1813-1822}, pmid = {33772618}, issn = {1432-0991}, mesh = {Antifungal Agents ; *Bacillus licheniformis ; Biofilms ; *Candida glabrata/genetics ; Glycolipids/pharmacology ; }, abstract = {In the present investigation, we have evaluated the antibiofilm potential of Bacillus licheniformis SV1 derived glycolipid against C. glabrata biofilm. Impact of isolated glycolipid on the viability of C. glabrata and on inhibiting as well as eradicating ability of its biofilm were studied. Further, morphological alterations, reactive oxygen species generation (ROS) production and transcriptional expression of selected genes (RT-PCR) of C. glabrata in response with isolated glycolipid were studied. The isolated glycolipid (1.0 mg ml[-1]) inhibited and eradicated C. glabrata biofilm approximately 80% and 60%, respectively. FE-SEM images revealed glycolipid exposure results in architectural alteration and eradication of C. glabrata biofilm and ROS generation. Transcriptional studies of selected genes showed that the expression of AUS1, FKS1 and KRE1 were down-regulated, while that of ergosterol biosynthesis pathway and multidrug transporter increased, in the presence of glycolipid.}, } @article {pmid33772566, year = {2021}, author = {Amate-Fernández, P and Figueiredo, R and Blanc, V and Àlvarez, G and León, R and Valmaseda-Castellón, E}, title = {Erythritol-enriched powder and oral biofilm regrowth on dental implants: an in vitro study.}, journal = {Medicina oral, patologia oral y cirugia bucal}, volume = {26}, number = {5}, pages = {e602-e610}, pmid = {33772566}, issn = {1698-6946}, mesh = {Biofilms ; *Dental Implants ; Erythritol ; Humans ; *Peri-Implantitis ; Powders ; }, abstract = {BACKGROUND: Peri-implant mucositis and peri-implantitis are the main biological complications associated with dental implants. Since most authors agree that bacteria play a major etiological role, the main aims of this study were to determine if a formulation of erythritol and chlorhexidine applied with an air polishing system inhibits biofilm regrowth over dental implants and to compare the decontamination capacity of this therapy with that of mechanical removal by saline and gauze.

MATERIAL AND METHODS: A multispecies biofilm (P. gingivalis, A. actinomycetemcomitans, F. nucleatum, A. naeslundii, V. parvula and S. oralis) was grown for 14 days on 52 dental implants in an artificial mouth. These implants were divided into three groups according to the applied treatment: 14 negative control (CON), 19 erythritol-chlorhexidine (ERY) and 19 gauze with saline (GAU) samples. Twelve dental implants from the ERY and GAU groups and 8 implants from the CON group were re-incubated for 7 additional days after treatment. The bacterial count was performed by quantitative polymerase chain reaction (qPCR) using propidium monoazide (PMA). A descriptive and bivariate analysis of the data was performed.

RESULTS: The erythritol and chlorhexidine formulation significantly inhibited biofilm regrowth in comparison with the mechanical treatment (GAU), since a significant decrease in all the species was observed in the ERY group (except for Aggregatibacter actinomycetemcomitans). The antibiofilm and antibacterial capacity of the two active treatment groups (ERY and GAU) was similar for a 14 days multispecies in vitro biofilm, except for the lower count of A. naeslundii in the GAU group.

CONCLUSIONS: The use of erythritol powder with chlorhexidine applied with an air polishing system reduces biofilm regrowth over dental implants when compared with mechanical removal by saline and gauze. This effect might be beneficial for patients included in peri-implant maintenance programs.}, } @article {pmid33771780, year = {2021}, author = {Zhang, SD and Isbrandt, T and Lindqvist, LL and Larsen, TO and Gram, L}, title = {Holomycin, an Antibiotic Secondary Metabolite, Is Required for Biofilm Formation by the Native Producer Photobacterium galatheae S2753.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {11}, pages = {}, pmid = {33771780}, issn = {1098-5336}, mesh = {Anti-Bacterial Agents/biosynthesis/*metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Lactams/*metabolism ; Mutation ; Photobacterium/*physiology ; }, abstract = {While the effects of antibiotics on microorganisms are widely studied, it remains less well understood how antibiotics affect the physiology of the native producing organisms. Here, using a marine bacterium, Photobacterium galatheae S2753, that produces the antibiotic holomycin, we generated a holomycin-deficient strain by in-frame deletion of hlmE, the core gene responsible for holomycin production. Mass spectrometry analysis of cell extracts confirmed that the ΔhlmE strain did not produce holomycin and that the mutant was devoid of antibacterial activity. Biofilm formation of the ΔhlmE strain was significantly reduced compared to that of wild-type S2753 and was restored in an hlmE complementary mutant. Consistent with this, exogenous holomycin, but not its dimethylated and less antibacterial derivative, S,S'-dimethyl holomycin, restored the biofilm formation of the ΔhlmE strain. Furthermore, zinc starvation was found to be essential for both holomycin production and biofilm formation of S2753, although the molecular mechanism remains elusive. Collectively, these data suggest that holomycin promotes biofilm formation of S2753 via its ene-disulfide group. Lastly, the addition of holomycin at subinhibitory concentrations also enhanced the biofilms of four other Vibrionaceae strains. P. galatheae likely gains an ecological advantage from producing holomycin as both an antibiotic and a biofilm stimulator, which facilitates nutrition acquisition and protects P. galatheae from environmental stresses. Studying the function of antibiotic compounds in the native producer will shed light on their roles in nature and could point to novel bioprospecting strategies.IMPORTANCE Despite the societal impact of antibiotics, their ecological functions remain elusive and have mostly been studied by exposing nonproducing bacteria to subinhibitory concentrations. Here, we studied the effects of the antibiotic holomycin on its native producer, Photobacterium galatheae S2753, a Vibrionaceae bacterium. Holomycin provides a distinct advantage to S2753 both as an antibiotic and by enhancing biofilm formation in the producer. Vibrionaceae species successfully thrive in global marine ecosystems, where they play critical ecological roles as free-living, symbiotic, or pathogenic bacteria. Genome mining has demonstrated that many have the potential to produce several bioactive compounds, including P. galatheae To unravel the contribution of the microbial metabolites to the development of marine microbial ecosystems, better insight into the function of these compounds in the producing organisms is needed. Our finding provides a model to pursue this and highlights the ecological importance of antibiotics to the fitness of the producing organisms.}, } @article {pmid33770266, year = {2021}, author = {Jiale, Z and Jian, J and Xinyi, T and Haoji, X and Xueqin, H and Xiao, W}, title = {Design of a novel antimicrobial peptide 1018M targeted ppGpp to inhibit MRSA biofilm formation.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {49}, pmid = {33770266}, issn = {2191-0855}, support = {82002190//National Natural Science Foundation of China/ ; 2019A610196//Natural Science Foundation of Ningbo/ ; 421807120, 421906052, 422003802//Research Fund of Ningbo University/ ; LY18H280004//Zhejiang Provincial Natural Science Foundation/ ; }, abstract = {Methicillin-resistant staphylococcus aureus (MRSA) and its biofilm infection were considered as one of the main international health issues. There are still many challenges for treatment using traditional antibiotics. In this study, a mutant peptide of innate defense regulator (IDR-)1018 named 1018M was designed based on molecular docking and amino acid substitution technology. The antibacterial/biofilm activity and mechanisms against MRSA of 1018M were investigated for the first time. The minimum inhibitory concentration (MIC) of 1018M was reduced 1 time (MIC = 2 μg/mL) compared to IDR-1018. After treatment with 32 μg/mL 1018M for 24 h, the percentage of biofilm decreased by 78.9%, which was more effective than the parental peptide. The results of mechanisms exploration showed that 1018M was more potent than IDR-1018 at destructing bacterial cell wall, permeating cell membrane (20.4%-50.1% vs 1.45%-10.6%) and binding to stringent response signaling molecule ppGpp (increased 27.9%). Additionally, the peptides could also exert their activity by disrupting genomic DNA, regulating the expression of ppGpp metabolism and biofilm forming related genes (RSH, relP, relQ, rsbU, sigB, spA, codY, agrA and icaD). Moreover, the higher temperature, pH and pepsase stabilities provide 1018M better processing, storage and internal environmental tolerance. These data indicated that 1018M may be a potential candidate peptide for the treatment of MRSA and its biofilm infections.}, } @article {pmid33770177, year = {2021}, author = {Chen, G and Lin, M and Chen, Y and Xu, W and Zhang, H}, title = {Induction of a Viable but Nonculturable State, Thermal and Sanitizer Tolerance, and Gene Expression Correlation with Desiccation-Adapted Biofilm and Planktonic Salmonella in Powdered Infant Formula.}, journal = {Journal of food protection}, volume = {84}, number = {7}, pages = {1194-1201}, doi = {10.4315/JFP-20-402}, pmid = {33770177}, issn = {1944-9097}, mesh = {Biofilms ; *Desiccation ; Gene Expression ; Humans ; Infant ; Infant Formula ; *Plankton ; Powders ; }, abstract = {ABSTRACT: This study was conducted to investigate the effects of the physiological state, desiccation adaptation, and storage of powdered infant formula on Salmonella cell survival and expression of desiccation stress-related genes. Powdered infant formula was inoculated with Salmonella Typhimurium in the biofilm state on beads and in the planktonic state on nitrocellulose filters and stored at 25°C for up to 270 days. Both 5-cyano-2,3-ditoyl tetrazolium chloride flow cytometry and xylose lysine deoxycholate agar plate counts revealed that biofilm-forming Salmonella cells tended to enter the viable but nonculturable (VBNC) state (P < 0.05). The population reduction of all desiccation-adapted Salmonella Typhimurium decreased significantly in both physiological states after exposure to mild heat (60°C) compared with nonadapted control cells (P < 0.05). Salmonella cells were cross-protected from heat in both physiological states, but cross-protection against hydrogen peroxide was induced for only planktonic Salmonella cells. The reverse transcription quantitative PCR results revealed that the rpoS gene in biofilm Salmonella cells on all desiccation adaption days and in planktonic Salmonella cells on day 7 of dry storage was significantly upregulated (P < 0.05). The rpoE, grpE, and invA genes in Salmonella cells in both physiological states were significantly down-regulated (P < 0.05). Physiological state and storage time might affect expression of these genes. Prior exposure to adverse conditions, including low water activity, and the physiological state impacted Salmonella survival, and its ability to enter the VBNC state and gene expression.}, } @article {pmid33768506, year = {2021}, author = {Dula, S and Ajayeoba, TA and Ijabadeniyi, OA}, title = {Bacterial biofilm formation on stainless steel in the food processing environment and its health implications.}, journal = {Folia microbiologica}, volume = {66}, number = {3}, pages = {293-302}, pmid = {33768506}, issn = {1874-9356}, support = {118910//National Research Foundation/ ; }, mesh = {Bacterial Adhesion ; Bacterial Infections/prevention & control/transmission ; *Bacterial Physiological Phenomena ; *Biofilms/growth & development ; Disinfection ; *Food Handling/instrumentation/standards ; *Food Microbiology ; Humans ; *Stainless Steel ; }, abstract = {Biofilm formation (BF) and production in the food processing industry (FPI) is a continual threat to food safety and quality. Various bacterial pathogens possess the ability to adhere and produce biofilms on stainless steel (SS) in the FPI due to flagella, curli, pili, fimbrial adhesins, extra polymeric substances, and surface proteins. The facilitating environmental conditions (temperature, pressure, variations in climatic conditions), SS properties (surface energy, hydrophobicity, surface roughness, topography), type of raw food materials, pre-processing, and processing conditions play a significant role in the enhancement of bacterial adhesion and favorable condition for BF. Furthermore, biofilm formers can tolerate different sanitizers and cleaning agents due to the constituents, concentration, contact time, bacterial cluster distribution, and composition of bacteria within the biofilm. Also, bacterial biofilms' ability to produce various endotoxins and exotoxins when consumed cause food infections and intoxications with serious health implications. It is thus crucial to understand BF's repercussions and develop effective interventions against these phenomena that make persistent pathogens difficult to remove in the food processing environment.}, } @article {pmid33767047, year = {2021}, author = {Carlson, AL and He, H and Yang, C and Daigger, GT}, title = {Comparison of hybrid membrane aerated biofilm reactor (MABR)/suspended growth and conventional biological nutrient removal processes.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {83}, number = {6}, pages = {1418-1428}, doi = {10.2166/wst.2021.062}, pmid = {33767047}, issn = {0273-1223}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; Nutrients ; Phosphorus ; *Sewage ; *Waste Disposal, Fluid ; }, abstract = {Mathematical modelling was used to investigate the possibility to use membrane aerated biofilm reactors (MABRs) in a largely anoxic suspended growth bioreactor to produce the nitrate-nitrogen required for heterotrophic denitrification and the growth of denitrifying phosphorus accumulating organisms (DPAOs). The results indicate that such a process can be used to achieve a variety of process objectives. The capture of influent biodegradable organic matter while also achieving significant total inorganic nitrogen (TIN) removal can be achieved with or without use of primary treatment by operation at a relatively short suspended growth solids residence time (SRT). Low effluent TIN concentrations can also be achieved, irrespective of the influent wastewater chemical oxygen demand (COD)/total nitrogen (TN) ratio, with somewhat larger suspended growth SRT. Biological phosphorus and nitrogen removal can also be effectively achieved. Further experimental work is needed to confirm these modelling results.}, } @article {pmid33767042, year = {2021}, author = {Bagastyo, AY and Hidayati, AS and Herumurti, W and Nurhayati, E}, title = {Application of boron-doped diamond, Ti/IrO2, and Ti/Pt anodes for the electrochemical oxidation of landfill leachate biologically pretreated by moving bed biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {83}, number = {6}, pages = {1357-1368}, doi = {10.2166/wst.2021.060}, pmid = {33767042}, issn = {0273-1223}, mesh = {Biofilms ; Bioreactors ; Boron ; *Diamond ; Electrodes ; Indonesia ; Oxidation-Reduction ; Titanium ; *Water Pollutants, Chemical/analysis ; }, abstract = {Conventional biological treatments used in most Indonesian landfill sites are mostly ineffective in treating stabilized landfill leachates to meet the standard regulation. Thus, a combination of biological and electrochemical process is offered to successfully treat leachates containing a high concentration of organic and nitrogenous compounds. In this study, a moving bed biofilm reactor (MBBR) was applied prior to electrochemical oxidation by using boron-doped diamond (BDD), Ti/IrO2, and Ti/Pt anodes with applied current of 350, 400 and 450 mA. The objectives were to investigate the effect of anode type and the applied current on the removal of organics as well as total nitrogen from the MBBR-treated leachate with electrochemical oxidation. The optimum removal of chemical oxygen demand (COD) observed on the Ti/Pt anode was 78% by applying 400 mA, with an estimated energy of 56.7 Wh g L[-1]. In the case of Ti/IrO2 and BDD anodes, the optimum removal of COD was 76 and 85% with an energy consumption of 58.9 and 36.9 Wh g L[-1], respectively, both achieved at 350 mA. Although all anodes showed less-satisfactory performances for total nitrogen reduction, around 46-95% removal of nitrogenous compounds was achieved by MBBR, with their partial conversion to nitrates.}, } @article {pmid33766592, year = {2021}, author = {Karthik, CS and Chethana, MH and Manukumar, HM and Ananda, AP and Sandeep, S and Nagashree, S and Mallesha, L and Mallu, P and Jayanth, HS and Dayananda, BP}, title = {Synthesis and characterization of chitosan silver nanoparticle decorated with benzodioxane coupled piperazine as an effective anti-biofilm agent against MRSA: A validation of molecular docking and dynamics.}, journal = {International journal of biological macromolecules}, volume = {181}, number = {}, pages = {540-551}, doi = {10.1016/j.ijbiomac.2021.03.119}, pmid = {33766592}, issn = {1879-0003}, mesh = {Animals ; Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Cell Line ; Chitosan/*chemical synthesis/chemistry ; Dioxanes/*pharmacology ; Fluorescence ; Ligands ; Metal Nanoparticles/*chemistry/ultrastructure ; Methicillin-Resistant Staphylococcus aureus/drug effects/*physiology/ultrastructure ; Microbial Sensitivity Tests ; *Molecular Docking Simulation ; *Molecular Dynamics Simulation ; Piperazine/chemistry/*pharmacology ; Plankton/drug effects ; Rats ; Silver/*pharmacology ; Toxicity Tests ; }, abstract = {Biomaterial research has improved the delivery and efficacy of drugs over a wide range of pharmaceutical applications. The objective of this study was to synthesize benzodioxane coupled piperazine decorated chitosan silver nanoparticle (Bcp*C@AgNPs) against methicillin-resistant Staphylococcus aureus (MRSA) and to assess the nanoparticle as an effective candidate for antibacterial and anti-biofilm care. Antibacterial activity of the compound was examined and minimum inhibitory concentration (MIC) was observed at (10.21 ± 0.03 ZOI) a concentration of 200 μg/mL. The Bcp*C@AgNPs interferes with surface adherence of MRSA, suggesting an anti-biofilm distinctive property that is verified for the first time by confocal laser microscopic studies. By ADMET studies the absorption, distribution, metabolism, excretion and toxicity of the compound was examined. The interaction solidity and the stability of the compound when surrounded by water molecules were analyzed by docking and dynamic simulation analysis. The myoblast cell line (L6) was considered for toxicity study and was observed that the compound exhibited less toxic effect. This current research highlights the biocidal efficiency of Bcp*C@AgNPs with their bactericidal and anti-biofilm properties over potential interesting clinical trial targets in future.}, } @article {pmid33765193, year = {2021}, author = {Lopes, CCA and Rodrigues, RB and Cenci, MS and Uehara, JLS and Maske, TT and Limirio, PHJO and Soares, PBF and Novais, VR}, title = {Effect of ionizing radiation and cariogenic biofilm challenge on root-dentin caries.}, journal = {Clinical oral investigations}, volume = {25}, number = {6}, pages = {4059-4068}, pmid = {33765193}, issn = {1436-3771}, mesh = {Biofilms ; *Dental Caries ; Dental Caries Susceptibility ; Dentin ; Humans ; Radiation, Ionizing ; *Root Caries ; }, abstract = {OBJECTIVES: To evaluate the effect of ionizing radiation and cariogenic biofilm challenge using two continuous flow models, normal and reduced salivary flow, on the development of initial root-dentin caries lesions.

MATERIALS AND METHODS: Microcosm biofilms were grown under two salivary flow rates (0.06 and 0.03 mL min[-1]) and exposed to 5% sucrose (3 × daily, 0.25 mL min[-1], 6 min) dripped over non-irradiated and irradiated root-dentin blocks for up to 7 days. The vibration modes of root dentin, matrix/mineral (M/M), and carbonate/mineral (C/M) ratios were evaluated by FTIR. The mineral density was assessed by micro-CT.

RESULTS: With normal salivary flow, FTIR revealed an increase in the organic matrix (amide III) and a decrease in the mineral phase (ν4, ν2 PO4[3-], AII + ν2 CO3[2-], C/M) in caries lesions. Irradiated dentin exhibited a reduction in the mineral phase (ν1, ν3 PO4[3-], ν2 CO3[2-], C/M). Differences in mineral densities were not significant. With reduced salivary flow, FTIR also revealed increased organic matrix (amide III) for irradiated caries lesions and decrease in mineral phase (v4, v2 PO4[3-], v2 CO3[2-], and C/M) in caries lesions. ν1, ν3 PO4[3-] precipitated on the surface of irradiated dentin and a lower mineral density was observed.

CONCLUSIONS: Initial caries lesions differed between non-irradiated and irradiated dentin and between normal and reduced salivary flow rates. Significant mineral loss with exposure of the organic matrix and low mineral density were observed for irradiated dentin with a reduced salivary flow rate.

CLINICAL RELEVANCE: Ionizing radiation associated with a reduced salivary flow rate enhanced the progression of root-dentin caries.}, } @article {pmid33765192, year = {2021}, author = {Konečná, K and Němečková, I and Diepoltová, A and Vejsová, M and Janďourek, O}, title = {The Impact of Cultivation Media on the In Vitro Biofilm Biomass Production of Candida spp.}, journal = {Current microbiology}, volume = {78}, number = {5}, pages = {2104-2111}, pmid = {33765192}, issn = {1432-0991}, mesh = {Antifungal Agents ; Biofilms ; Biomass ; *Candida ; *Candida albicans ; Culture Media ; }, abstract = {The yeasts of the genus Candida are among the most clinically significant fungal pathogenic agents. One of the unique features of the Candida species' pathogenicity is their ability to form biofilms. Generally, infections caused by biofilm-forming microorganisms tend to have chronic course and are difficult to treat. This fact highlights the need to search for drugs with anti-biofilm activities. At present, there are variety of protocols for performing antifungal anti-biofilm activity testing in which fundamental differences, especially in the choice of cultivation media for biofilm formation, can be noted. In our study, we focused on the effect of four different culture media on biofilm biomass formation in ten Candida spp. strains. With emphasis placed on clinical significance, strains of the C. albicans species were predominantly included in this study. Based on our results, we can conclude that the availability of other components in the culture media, such as amino acids or proteins, and not just the commonly mentioned glucose availability, helps promote the transition of Candida yeasts into a sessile form and leads to in vitro robust biofilm formation. We revealed that biofilm formation in C. albicans strains was enhanced, especially in media supplemented with fetal bovine serum (FBS). The nutritionally balanced cultivation medium with 10 g/L glucose and 10% (v/v) FBS evidently showed the most significant benefit for in vitro biofilm production in C. albicans strains.}, } @article {pmid33764668, year = {2021}, author = {Martín-Rodríguez, AJ and Villion, K and Yilmaz-Turan, S and Vilaplana, F and Sjöling, Å and Römling, U}, title = {Regulation of colony morphology and biofilm formation in Shewanella algae.}, journal = {Microbial biotechnology}, volume = {14}, number = {3}, pages = {1183-1200}, pmid = {33764668}, issn = {1751-7915}, mesh = {Biofilms ; Humans ; Mutagenesis ; *Shewanella/genetics ; Virulence ; }, abstract = {Bacterial colony morphology can reflect different physiological stages such as virulence or biofilm formation. In this work we used transposon mutagenesis to identify genes that alter colony morphology and cause differential Congo Red (CR) and Brilliant Blue G (BBG) binding in Shewanella algae, a marine indigenous bacterium and occasional human pathogen. Microscopic analysis of colonies formed by the wild-type strain S. algae CECT 5071 and three transposon integration mutants representing the diversity of colony morphotypes showed production of biofilm extracellular polymeric substances (EPS) and distinctive morphological alterations. Electrophoretic and chemical analyses of extracted EPS showed differential patterns between strains, although the targets of CR and BBG binding remain to be identified. Galactose and galactosamine were the preponderant sugars in the colony biofilm EPS of S. algae. Surface-associated biofilm formation of transposon integration mutants was not directly correlated with a distinct colony morphotype. The hybrid sensor histidine kinase BarA abrogated surface-associated biofilm formation. Ectopic expression of the kinase and mutants in the phosphorelay cascade partially recovered biofilm formation. Altogether, this work provides the basic analysis to subsequently address the complex and intertwined networks regulating colony morphology and biofilm formation in this poorly understood species.}, } @article {pmid33763710, year = {2021}, author = {Zhou, G and Wang, YS and Peng, H and Li, SJ and Sun, TL and Shen, PF and Xie, XB and Shi, QS}, title = {Roles of ompA of Citrobacter werkmanii in bacterial growth, biocide resistance, biofilm formation and swimming motility.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {7}, pages = {2841-2854}, pmid = {33763710}, issn = {1432-0614}, support = {31770091//National Natural Science Foundation of China/ ; 2019GDASYL-0104006//GDAS' Project of Science and Technology Development/ ; 2020A151501848//Natural Science Foundation of Guangdong Province/ ; }, mesh = {Bacterial Proteins/genetics ; Biofilms ; Citrobacter/genetics ; *Disinfectants ; Gene Expression Regulation, Bacterial ; Swimming ; }, abstract = {The genus Citrobacter is commonly found in environmental and industrial settings, some members of which have been used for bioremediation of heavy metals owing to the absorption ability of their biofilms. Although our previous studies have found that the outer membrane protein A (OmpA) contributes to the process of Citrobacter werkmanii biofilm formation, the underlying mechanisms remain elusive. Therefore, we deleted ompA from the genome of C. werkmanii and investigated its phenotypes in comparison to the wild type strain (WT) and the complementary strain using biochemical and molecular techniques including RNA-Seq. Our results demonstrated that the deletion of ompA led to an increase in biofilm formation on both polystyrene and glass surfaces due to upregulation of some biofilm formation related genes. Meanwhile, swimming ability, which is mediated by activation of flagellar assembly genes, was increased on semi-solid plates in the ∆ompA strain when compared with WT. Additionally, inactivation of ompA also caused increased 1,2-benzisothiazolin-3-one (BIT) resistance, differential responses to Ca[2+] stress, curli protein expression and cellulose production. Finally, ∆ompA caused differential expression of a total of 1470 genes when compared with WT, of which 146 were upregulated and 1324 were downregulated. These genes were classified into different Gene Ontology (GO) and KEGG pathways. In summary, ompA in C. werkmanii contributes to a variety of biological functions and may act as a target site to modulate biofilm formation. KEY POINTS: • ompA is a negative regulator for biofilm formation by C. werkmanii. • ompA inhibits swimming motility of C. werkmanii. • ompA deletion causes different expression profiles in C. werkmanii.}, } @article {pmid33763049, year = {2021}, author = {Mu, Y and Zeng, H and Chen, W}, title = {Quercetin Inhibits Biofilm Formation by Decreasing the Production of EPS and Altering the Composition of EPS in Staphylococcus epidermidis.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {631058}, pmid = {33763049}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis is an opportunistic pathogen, and its biofilm formation ability is an important virulent factor. Quercetin, a typical flavonoid ubiquitously used in dietary supplementation, is known for its antioxidant property, but its anti-biofilm activity against S. epidermidis remains unknown. In this study, the anti-biofilm activity of quercetin was investigated using S. epidermidis ATCC35984, a strong biofilm-positive strain. An attempt was made to disclose the mechanisms of the anti-biofilm activity of quercetin. S. epidermidis exhibited a less cell surface hydrophobicity after quercetin treatment. Also, quercetin effectively inhibited S. epidermidis cells from adhering to the glass slides. Quercetin downregulated the intercellular adhesion (ica) locus and then polysaccharide intercellular adhesin (PIA) production was reduced. Therefore, S. epidermidis cells became less hydrophobic, which supported quercetin's anti-biofilm effect. Our study suggests that quercetin from plants be given further attention as a potential anti-biofilm agent against the biofilm formation of S. epidermidis, even biofilm infections of other bacteria.}, } @article {pmid33760986, year = {2021}, author = {Feng, D and Neuweiler, I and Nogueira, R and Nackenhorst, U}, title = {Modeling of Symbiotic Bacterial Biofilm Growth with an Example of the Streptococcus-Veillonella sp. System.}, journal = {Bulletin of mathematical biology}, volume = {83}, number = {5}, pages = {48}, pmid = {33760986}, issn = {1522-9602}, mesh = {*Biofilms ; *Models, Biological ; *Streptococcus/physiology ; Symbiosis/physiology ; *Veillonella/physiology ; }, abstract = {We present a multi-dimensional continuum mathematical model for modeling the growth of a symbiotic biofilm system. We take a dual-species namely, the Streptococcus-Veillonella sp. biofilm system as an example for numerical investigations. The presented model describes both the cooperation and competition between these species of bacteria. The coupled partial differential equations are solved by using an integrative finite element numerical strategy. Numerical examples are carried out for studying the evolution and distribution of the bio-components. The results demonstrate that the presented model is capable of describing the symbiotic behavior of the biofilm system. However, homogenized numerical solutions are observed locally. To study the homogenization behavior of the model, numerical investigations regarding on how random initial biomass distribution influences the homogenization process are carried out. We found that a smaller correlation length of the initial biomass distribution leads to faster homogenization of the solution globally, however, shows more fluctuated biomass profiles along the biofilm thickness direction. More realistic scenarios with bacteria in patches are also investigated numerically in this study.}, } @article {pmid33758085, year = {2021}, author = {Wilks, SA and Koerfer, VV and Prieto, JA and Fader, M and Keevil, CW}, title = {Biofilm Development on Urinary Catheters Promotes the Appearance of Viable but Nonculturable Bacteria.}, journal = {mBio}, volume = {12}, number = {2}, pages = {}, pmid = {33758085}, issn = {2150-7511}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/classification/*growth & development/isolation & purification ; Biofilms/*growth & development ; Colony Count, Microbial ; Escherichia coli/growth & development ; Hydrogels ; Latex ; *Microbial Viability ; Proteus mirabilis/growth & development ; Pseudomonas aeruginosa/growth & development ; Silicones ; Surface Properties/drug effects ; Urinary Catheters/*microbiology ; }, abstract = {Catheter-associated urinary tract infections have serious consequences, for both patients and health care resources. Much work has been carried out to develop an antimicrobial catheter. Although such developments have shown promise under laboratory conditions, none have demonstrated a clear advantage in clinical trials. Using a range of microbiological and advanced microscopy techniques, a detailed laboratory study comparing biofilm development on silicone, hydrogel latex, and silver alloy-coated hydrogel latex catheters was carried out. Biofilm development by Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis on three commercially available catheters was tracked over time. Samples were examined with episcopic differential interference contrast (EDIC) microscopy, culture analysis, and staining techniques to quantify viable but nonculturable (VBNC) bacteria. Both qualitative and quantitative assessments found biofilms to develop rapidly on all three materials. EDIC microscopy revealed the rough surface topography of the materials. Differences between culture counts and quantification of total and dead cells demonstrated the presence of VBNC populations, where bacteria retain viability but are not metabolically active. The use of nonculture-based techniques showed the development of widespread VBNC populations. These VBNC populations were more evident on silver alloy-coated hydrogel latex catheters, indicating a bacteriostatic effect at best. The laboratory tests reported here, which detect VBNC bacteria, allow more rigorous assessment of antimicrobial catheters, explaining why there is often minimal benefit to patients.IMPORTANCE Several antimicrobial urinary catheter materials have been developed, but, although laboratory studies may show a benefit, none have significantly improved clinical outcomes. The use of poorly designed laboratory testing and lack of consideration of the impact of VBNC populations may be responsible. While the presence of VBNC populations is becoming more widely reported, there remains a lack of understanding of the clinical impact or influence of exposure to antimicrobial products. This is the first study to investigate the impact of antimicrobial surface materials and the appearance of VBNC populations. This demonstrates how improved testing is needed before clinical trials are initiated.}, } @article {pmid33756183, year = {2021}, author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Esposito, G}, title = {Shortcut nitrification-denitrification and biological phosphorus removal in acetate- and ethanol-fed moving bed biofilm reactors under microaerobic/aerobic conditions.}, journal = {Bioresource technology}, volume = {330}, number = {}, pages = {124958}, doi = {10.1016/j.biortech.2021.124958}, pmid = {33756183}, issn = {1873-2976}, mesh = {Acetates ; Biofilms ; Bioreactors ; Denitrification ; Ethanol ; *Nitrification ; Nitrogen ; *Phosphorus ; Sewage ; Waste Disposal, Fluid ; }, abstract = {This study investigated the feasibility of coupling simultaneous partial nitrification and denitrification (SPND) to biological phosphorus removal in continuous-flow intermittently-aerated moving bed biofilm reactors (MBBRs) fed with different carbon sources, i.e. ethanol and acetate. Bacterial cultivation at pH 8.2 (±0.2), 26-28 °C and SRT of 4 day and microaerobic/aerobic MBBR operation allowed to achieve average dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO4[3-] removal efficiencies (REs) of 100%, 81-88% and 83-86% at HRT of 1 day, dissolved oxygen (DO) range of 0.2-3 mg L[-1] and feed C/N and C/P ratios of 3.6 and 11, respectively. Acetate supplementation favored a diversified microbial community, while overgrowth of heterotrophs was observed when increasing feed C/N ratio in ethanol-fed MBBR. Illumina sequencing displayed the presence of putative phosphorus accumulating organisms (PAOs) such as Hydrogenophaga and Pseudomonas in MBBR biofilm and suspended biomass, whereas no typical NOB was identified during the study.}, } @article {pmid33755306, year = {2021}, author = {Lu, J and Francis, JD and Guevara, MA and Moore, RE and Chambers, SA and Doster, RS and Eastman, AJ and Rogers, LM and Noble, KN and Manning, SD and Damo, SM and Aronoff, DM and Townsend, SD and Gaddy, JA}, title = {Antibacterial and Anti-biofilm Activity of the Human Breast Milk Glycoprotein Lactoferrin against Group B Streptococcus.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {22}, number = {12}, pages = {2124-2133}, pmid = {33755306}, issn = {1439-7633}, support = {UL1 TR000445/TR/NCATS NIH HHS/United States ; 1400969//National Science Foundation/ ; R01 HD090061/HD/NICHD NIH HHS/United States ; T32 AI112541/AI/NIAID NIH HHS/United States ; T32 HL007411/HL/NHLBI NIH HHS/United States ; F32 HD100087/HD/NICHD NIH HHS/United States ; UL1 RR024975/RR/NCRR NIH HHS/United States ; K08 AI151100/AI/NIAID NIH HHS/United States ; U01 TR002398/TR/NCATS NIH HHS/United States ; R35 GM133602/GM/NIGMS NIH HHS/United States ; 1547757//National Science Foundation/ ; R01 AI134036/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects/immunology ; Biofilms/drug effects ; Female ; Humans ; Immunity, Innate/drug effects/immunology ; Lactoferrin/chemistry/*immunology ; Microbial Sensitivity Tests ; Milk, Human/*chemistry ; Streptococcus agalactiae/*drug effects/immunology ; }, abstract = {Group B Streptococcus (GBS) is an encapsulated Gram-positive human pathogen that causes invasive infections in pregnant hosts and neonates, as well as immunocompromised individuals. Colonization of the human host requires the ability to adhere to mucosal surfaces and circumnavigate the nutritional challenges and antimicrobial defenses associated with the innate immune response. Biofilm formation is a critical process to facilitate GBS survival and establishment of a replicative niche in the vertebrate host. Previous work has shown that the host responds to GBS infection by producing the innate antimicrobial glycoprotein lactoferrin, which has been implicated in repressing bacterial growth and biofilm formation. Additionally, lactoferrin is highly abundant in human breast milk and could serve a protective role against invasive microbial pathogens. This study demonstrates that human breast milk lactoferrin has antimicrobial and anti-biofilm activity against GBS and inhibits its adherence to human gestational membranes. Together, these results indicate that human milk lactoferrin could be used as a prebiotic chemotherapeutic strategy to limit the impact of bacterial adherence and biofilm formation on GBS-associated disease outcomes.}, } @article {pmid33754966, year = {2021}, author = {Fisher, EW and Fishman, J}, title = {Anti-biofilm topical therapy in rhinosinusitis, coronavirus in India, anosmia prognosis, fish bones and flexible laryngoscopy.}, journal = {The Journal of laryngology and otology}, volume = {135}, number = {3}, pages = {189-190}, doi = {10.1017/S0022215121000761}, pmid = {33754966}, issn = {1748-5460}, mesh = {*Biofilms ; COVID-19/*epidemiology ; Foreign Bodies/*therapy ; Humans ; India/epidemiology ; *Laryngoscopy ; Rhinitis/*therapy ; Sinusitis/*therapy ; }, } @article {pmid33752004, year = {2021}, author = {Uri-Carreño, N and Nielsen, PH and Gernaey, KV and Flores-Alsina, X}, title = {Long-term operation assessment of a full-scale membrane-aerated biofilm reactor under Nordic conditions.}, journal = {The Science of the total environment}, volume = {779}, number = {}, pages = {146366}, doi = {10.1016/j.scitotenv.2021.146366}, pmid = {33752004}, issn = {1879-1026}, mesh = {Biofilms ; *Bioreactors ; Europe ; Nitrogen ; Oxygen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Membrane-aerated biofilm reactor (MABR) technology is an exciting alternative to conventional activated sludge, with promising results in bench and pilot-scale systems. Nevertheless, there is still a lack of long-term and full-scale data under different operational conditions. This study aims to report the performance of a full-scale hybrid MABR located in the North of Europe. Influent, effluent, and exhaust data were collected for 1 year (September 2019 to September 2020) using online sensors/gas-analyzers and off-line laboratory analysis. Next, oxygen transfer rate (OTR), oxygen transfer efficiency (OTE), and nitrification rates (NR) were quantified as process indicators. Finally, multivariate methods were used to find patterns among monitored variables. Observations revealed that lower airflows achieved higher OTE at the same values of OTR and OTR was strongly correlated to ammonia/um concentration in the MABR tank (NHx,eff). The dynamics between oxygen concentration in the exhaust (O2,exh) and NHx,eff indicated that a nitrifying biofilm was established within 3 weeks. Average NR were calculated using four different methods and ranged between 1 and 2 g N m[-2]d[-1]. Principal component analysis (PCA) explained 81.4% of the sample variance with the first three components and cluster analysis (CA) divided the yearly data into five distinctive periods. Hence, it was possible to identify typical Nordic episodes with high frequency of heavy rain, low temperature, and high variations in pollution load. The study concludes that nitrification capacity obtained with MABR is robust during cold weather conditions, and its volumetric value is comparable to other well-established biofilm-based technologies. Moreover, the aeration efficiency (AE) obtained in this study, 5.8 kg O2 kW h[-1], would suppose an average reduction in energy consumption of 55% compared to fine pore diffused aeration and 74% to the existing surface aeration at the facility.}, } @article {pmid33750997, year = {2022}, author = {Costa, MS and Lovato da Silva, CH and de Cássia Oliveira, V and Watanabe, E and Dos Reis, A and Lepri, CP and de Castro, DT}, title = {Effects of Different Forms of Denture Adhesives on Biofilm Formation, Adhesive Strength and Hygiene of Complete Dentures.}, journal = {The International journal of prosthodontics}, volume = {35}, number = {6}, pages = {784–792}, doi = {10.11607/ijp.7188}, pmid = {33750997}, issn = {1942-4426}, abstract = {PURPOSE: To evaluate the effect of different forms of denture adhesives on the formation of biofilm and on adhesive strength, as well as the effectiveness of hygiene protocols for their removal.

MATERIALS AND METHODS: Samples of the heat-cured polymethyl methacrylate denture base resin were made and divided into four groups: control (no adhesive), ultra Corega cream, Corega strip adhesive, and ultra Corega powder (GlaxoSmithKline). Biofilm formation was evaluated by counting colony-forming units and fluorescence microscopy. To evaluate the effectiveness of the hygiene protocols, the samples were divided into five subgroups: brushing with distilled water; brushing with Protex soap; brushing with Colgate toothpaste; immersion in Corega Tabs; and immersion in Corega Tabs followed by brushing with the solution itself. The remaining adhesive was quantified with ImageJ software. The adhesive strength was tested at different time intervals after application. After verifying the data distribution using Shapiro-Wilk test, parametric or nonparametric analysis was applied (α = .05).

RESULTS: Candida albicans formed more biofilm in strip (P = .007) and powder (P = .001), Pseudomonas aeruginosa in cream (P < .001) and powder (P < .001), and Staphylococcus aureus in strip (P < .001). All forms of the adhesives promoted higher biofilm formation when compared to control (P = .003). Brushing with Colgate and Protex was most effective for removing the adhesives (P < .05). Independently, Powder had the highest adhesive strength (P < .05). Only Strip showed a change in adhesive strength, with higher values after 3 hours of application (P = .004).

CONCLUSION: Daily treatments with mechanical cleaning of the prosthesis are important for removing the adhesives, since the presence of this material can favor biofilm accumulation. The adhesive strength may vary depending on the commercial type, but all forms can be effective in retaining prostheses for a satisfactory period of time.}, } @article {pmid33750633, year = {2021}, author = {Premkumar, A and Nishtala, SN and Nguyen, JT and Bostrom, MPG and Carli, AV}, title = {The AAHKS Best Podium Presentation Research Award: Comparing the Efficacy of Irrigation Solutions on Staphylococcal Biofilm Formed on Arthroplasty Surfaces.}, journal = {The Journal of arthroplasty}, volume = {36}, number = {7S}, pages = {S26-S32}, doi = {10.1016/j.arth.2021.02.033}, pmid = {33750633}, issn = {1532-8406}, mesh = {*Anti-Infective Agents, Local/pharmacology ; Arthroplasty ; *Awards and Prizes ; Biofilms ; Chlorhexidine ; Povidone-Iodine/pharmacology ; }, abstract = {BACKGROUND: A diverse array of antibacterial solutions is utilized by orthopedic surgeons in an attempt to disperse bacterial biofilm. Few studies compare these agents against biofilm grown on clinically relevant orthopedic biomaterials, such as plastic, acrylic cement, and porous titanium.

METHODS: MSSA biofilm was grown on plastic 48-well plates, polymethylmethacrylate cement beads and porous Ti-6Al-4V acetabular screw caps. Antibacterial solutions were tested according to manufacturer guidance and included: isotonic saline, vancomycin (1 mg/mL), polymyxin-bacitracin (500,000 U/L-50,000 U/L), povidone-iodine 0.3%, povidone-iodine 10%, a 1:1 combination of povidone-iodine 10% & 4% hydrogen peroxide, polyhexamethylene biguanide (PHMB) and betaine 0.04%, a commercial solution containing chlorhexidine gluconate (CHG) 0.05%, and a commercial solution containing benzalkonium chloride and ethanol. Twenty four and 72-hour biofilms were exposed to solutions for 3 minutes to reproduce intraoperative conditions. Solution efficacy was measured through sonication of treated surfaces followed by counting colony forming units and validated with a resazurin assay to assess cell viability. Experiments were performed in triplicate and repeated at least once. A three-fold log reduction in CFU counts versus controls was considered as a measure of solution efficacy.

RESULTS: Saline, vancomycin and polymyxin-bacitracin were ineffective compared to other solutions against planktonic MSSA. Povidone-iodine 10% and a 1:1 solution of povidone-iodine 10% and 4% hydrogen peroxide were the only effective solutions against biofilm across all three surfaces and time points.

CONCLUSION: Commercial antibacterial solutions vary significantly in their efficacy against MSSA biofilm. Efficacy globally decreased as biofilm maturity increased. Increased solution cost did not confer increased efficacy.}, } @article {pmid33750393, year = {2021}, author = {Song, H and Lou, N and Liu, J and Xiang, H and Shang, D}, title = {Label-free quantitative proteomic analysis of the inhibition effect of Lactobacillus rhamnosus GG on Escherichia coli biofilm formation in co-culture.}, journal = {Proteome science}, volume = {19}, number = {1}, pages = {4}, pmid = {33750393}, issn = {1477-5956}, support = {81601734//National Natural Science Foundation of China/ ; }, abstract = {BACKGROUND: Escherichia coli (E. coli) is the principal pathogen that causes biofilm formation. Biofilms are associated with infectious diseases and antibiotic resistance. This study employed proteomic analysis to identify differentially expressed proteins after coculture of E. coli with Lactobacillus rhamnosus GG (LGG) microcapsules.

METHODS: To explore the relevant protein abundance changes after E. coli and LGG coculture, label-free quantitative proteomic analysis and qRT-PCR were applied to E. coli and LGG microcapsule groups before and after coculture, respectively.

RESULTS: The proteomic analysis characterised a total of 1655 proteins in E. coli K12MG1655 and 1431 proteins in the LGG. After coculture treatment, there were 262 differentially expressed proteins in E. coli and 291 in LGG. Gene ontology analysis showed that the differentially expressed proteins were mainly related to cellular metabolism, the stress response, transcription and the cell membrane. A protein interaction network and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis indicated that the differentiated proteins were mainly involved in the protein ubiquitination pathway and mitochondrial dysfunction.

CONCLUSIONS: These findings indicated that LGG microcapsules may inhibit E. coli biofilm formation by disrupting metabolic processes, particularly in relation to energy metabolism and stimulus responses, both of which are critical for the growth of LGG. Together, these findings increase our understanding of the interactions between bacteria under coculture conditions.}, } @article {pmid33749365, year = {2021}, author = {Head, D and Marsh, PD and Devine, DA and Tenuta, LMA}, title = {In Silico Modeling of Hyposalivation and Biofilm Dysbiosis in Root Caries.}, journal = {Journal of dental research}, volume = {100}, number = {9}, pages = {977-982}, pmid = {33749365}, issn = {1544-0591}, mesh = {Biofilms ; Computer Simulation ; *Dental Caries/etiology ; Dentin ; Dysbiosis ; Humans ; *Root Caries ; *Tooth Demineralization ; *Xerostomia ; }, abstract = {Root caries progression is aggravated by hyposalivation, which can accelerate the conversion of a dental biofilm from having a symbiotic microbial relationship with the host (predominance of nonaciduric species) to a dysbiotic one (dominated by aciduric species). Using a mathematical model previously employed to investigate factors associated with biofilm dysbiosis, we systematically explored the deleterious effect of hyposalivation on the composition of the biofilm and the risk of root dentin demineralization. By varying the clearance half-times of sugar (i.e., readily fermented dietary carbohydrates), we simulated hyposalivation and investigated its effect on 1) the time that the biofilm pH spends below the minimum for dentin or enamel demineralization and 2) the conversion of the biofilm from a symbiotic to dysbiotic composition. The effect of increasing sugar clearance half-times on the time that the biofilm pH is below the threshold for demineralization was more pronounced for dentin than for enamel (e.g., increasing the clearance half-time from 2 to 6 min doubled the time that the biofilm pH was below the threshold for dentin demineralization). The effect on biofilm composition assessed at 50 d showed that the conversion from a symbiotic to a dysbiotic biofilm happened around a frequency of 6 sugar intakes per day when the clearance half-time was 2 min but only 3 sugar intakes per day when the clearance half-time was 6 min. Taken together, the results confirm the profound effect that prolonged sugar clearance has on the dynamics of dental biofilm composition and the subsequent risk of root caries. This in silico model should be applied to study how interventions that alter salivary clearance rates or modify biofilm pH can affect clinical conditions such as root caries.}, } @article {pmid33748870, year = {2021}, author = {Patel, RJ and Patel, UD and Nerurkar, AS}, title = {Moving bed biofilm reactor developed with special microbial seed for denitrification of high nitrate containing wastewater.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {4}, pages = {68}, pmid = {33748870}, issn = {1573-0972}, mesh = {Amyloid/metabolism ; Bacteria/genetics/isolation & purification/metabolism ; Benzothiazoles ; Biofilms/*growth & development ; *Bioreactors ; *Denitrification ; Kinetics ; Nitrates/*metabolism ; Nitrogen/metabolism ; Pseudomonas ; Sewage ; Wastewater ; Water Purification ; }, abstract = {Biological denitrification is the most promising alternative approach for the removal of nitrate from wastewater. MBBR inoculated with activated sludge is a widely studied approach, but very few studies have focused on the bioaugmentation of biofilm forming bacteria in MBBR. Our study revealed that the use of special microbial seed of biofilm forming denitrifying bacteria Diaphorobacter sp. R4, Pannonibacter sp. V5, Thauera sp. V9, Pseudomonas sp.V11, and Thauera sp.V14 to form biofilm on carriers enhanced nitrate removal performance of developed MBBR. Various process parameters C/N ratio 0.3, HRT 3 h at Nitrate loading 2400 mg L[-1], Filling ratio 20%, operated with Pall ring carrier were optimized to achieve highest nitrate removal. After 300 days of continuous operation results of whole genome metagenomic studies showed that Thauera spp. were the most dominant and key contributor to the denitrification of nitrate containing wastewater and the reactor was totally conditioned for denitrification. Overall, findings suggest that bench-scale MBBR developed with biofilm forming denitrifying microbial seed accelerated the denitrification process; therefore in conclusion it is suggested as one of the best suitable and effective approach for removal of nitrate from wastewater.}, } @article {pmid33747998, year = {2021}, author = {Davarzani, F and Saidi, N and Besharati, S and Saderi, H and Rasooli, I and Owlia, P}, title = {Evaluation of Antibiotic Resistance Pattern, Alginate and Biofilm Production in Clinical Isolates of Pseudomonas aeruginosa.}, journal = {Iranian journal of public health}, volume = {50}, number = {2}, pages = {341-349}, pmid = {33747998}, issn = {2251-6093}, abstract = {BACKGROUND: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa.

METHODS: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively.

RESULTS: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were Multidrug-Resistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates.

CONCLUSION: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.}, } @article {pmid33747747, year = {2021}, author = {Wang, J and Wang, L and Pan, J and Zhao, J and Tang, J and Jiang, D and Hu, P and Jia, W and Shi, J}, title = {Magneto-Based Synergetic Therapy for Implant-Associated Infections via Biofilm Disruption and Innate Immunity Regulation.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {8}, number = {6}, pages = {2004010}, pmid = {33747747}, issn = {2198-3844}, abstract = {Implant-associated infections (IAIs) are a common cause of orthopedic surgery failure due to microbial biofilm-induced antibiotic-resistance and innate immune inactivation. Thus, the destruction of microbial biofilm plays a key role in reducing IAIs. Herein, first, a magneto-based synergetic therapy (MST) is proposed and demonstrated against IAIs based on biofilm destruction. Under an alternating magnetic field (AMF), CoFe2O4@MnFe2O4 nanoparticles (MNPs), with a rather strong magnetic hyperthermal capacity, can generate sufficient thermal effect to cause dense biofilm dispersal. Loosened biofilms provide channels through which nitrosothiol-coated MNPs (MNP-SNOs) can penetrate. Subsequently, thermosensitive nitrosothiols rapidly release nitric oxide (NO) inside biofilms, thus efficiently killing sessile bacteria under the magnetothermal effect of MNPs. More importantly, MNP-SNOs can trigger macrophage-related immunity to prevent the relapse of IAIs by exposing the infected foci to a consistent innate immunomodulatory effect. The notable anti-infection effect of this nanoplatform is also confirmed in a rat IAI model. This work presents the promising potential of combining magnetothermal therapy with immunotherapy, for the effective and durable control and elimination of IAIs.}, } @article {pmid33746929, year = {2021}, author = {Lu, H and Zhao, L and Si, Y and Jian, Y and Wang, Y and Li, T and Dai, Y and Huang, Q and Ma, X and He, L and Li, M}, title = {The Surge of Hypervirulent ST398 MRSA Lineage With Higher Biofilm-Forming Ability Is a Critical Threat to Clinics.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {636788}, pmid = {33746929}, issn = {1664-302X}, abstract = {The global increase of community-associated (CA) infections with methicillin-resistant Staphylococcus aureus (MRSA) is a major healthcare problem. Although sequence type (ST) 398 MRSA was first described as a livestock-associated (LA) lineage, human-adapted MRSA (HO-MRSA) ST398 without livestock contact has subsequently been reported from China in our previous study and other later research. The proportion of ST398 HO-MRSA has also remarkably increased in recent years in China. Based on 3878 S. aureus isolates that were collected in a general hospital between 2008 and 2018, we identified 56 ST398 HO-MRSA isolates. The four early appearing isolates of them have been sequenced by whole-genome sequencing (WGS) in our previous study. Here, by usage of WGS on the later-appearing 52 isolates and analyzing the phylogenetic dynamics of the linage, we found that 50 isolates clustered together with the former 4 isolates, making it a main clade out of MSSA clones and other MRSA clones, although ST398 HO-MRSA evolved with multiple origins. Drug resistance and virulence gene analysis based on the WGS data demonstrated that ST398 HO-MRSA main clade exhibited a similar pattern in both parts. Furthermore, they all carried a conserved variant of prophage 3 to guarantee virulence and a short SCCmec type V element of class D to maintain considerable lower methicillin resistance. Further phenotypical research verified that the epidemic HO-MRSA ST398 displayed enhanced biofilm formation ability when keeping high virulence. The dual advantages of virulence and biofilm formation in the HO-MRSA ST398 subtype promote their fitness in the community and even in the healthcare environment, which poses a serious threat in clinical S. aureus infections. Therefore, further surveillance is required to prevent and control the problematic public health impact of HO-MRSA ST398 in the future.}, } @article {pmid33744647, year = {2021}, author = {Su, G and Deng, X and Zhong, H and Hu, L and Li, S and Praburaman, L and He, Z and Sun, W}, title = {Ag[+] significantly promoted the biofilm formation of thermoacidophilic archaeon Acidianus manzaensis YN-25 on chalcopyrite surface.}, journal = {Chemosphere}, volume = {276}, number = {}, pages = {130208}, doi = {10.1016/j.chemosphere.2021.130208}, pmid = {33744647}, issn = {1879-1298}, mesh = {*Acidianus ; Archaea ; Biofilms ; Copper ; Silver ; }, abstract = {Silver ion (Ag[+]) is an important catalyst to improve chalcopyrite bio-dissolution, but its effects on initial adhesion behaviors and biofilm formation of acidophiles onto metal sulfide were still unknown. In this study, initial attachment behavior and adhesion force in the presence of Ag[+] (0, 1, 2, 5, 10 and 20 mg/L) were comparatively analyzed for Acidianus manzaensis YN-25. Biofilm was observed by fluorescent images in the presence of 0, 1 and 2 mg/L Ag[+]. X-ray photoelectron spectroscopy (XPS) corroborated the catalytic mechanisms of Ag[+] to biofilm formation. Results showed that Ag[+] could significantly promote the attachment of cells on chalcopyrite, and the optimum concentration of Ag[+] was 2 mg/L with the biggest percentage of attached cells (74%), followed by 5 mg/L (71%), whereas that for the control (0 mg/L) was only 61%. Ag[+] significantly increased the interaction force between A. manzaensis YN-25 and chalcopyrite. Compared with the control, larger coverage of biofilm (up to 40% versus 32%) and more corrosion pits were observed on chalcopyrite in the presence of 2 mg/L Ag[+]. Moreover, Ag[+] catalyzed chalcopyrite corrosion and accelerated biofilm formation by producing a loose porous Ag2S layer and Ag[0] to decrease the resistivity. The live/dead ratio was small with a range of 0.31-1.38, suggesting that dead cells were a great slice during the whole life-cycle of biofilm on chalcopyrite. This report offers a profound insight into the promotion mechanism of Ag[+] on adhesion behaviors and biofilm formation by thermoacidophilic archaeon under extremely acidic conditions.}, } @article {pmid33741996, year = {2021}, author = {Seviour, T and Winnerdy, FR and Wong, LL and Shi, X and Mugunthan, S and Foo, YH and Castaing, R and Adav, SS and Subramoni, S and Kohli, GS and Shewan, HM and Stokes, JR and Rice, SA and Phan, AT and Kjelleberg, S}, title = {The biofilm matrix scaffold of Pseudomonas aeruginosa contains G-quadruplex extracellular DNA structures.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {27}, pmid = {33741996}, issn = {2055-5008}, mesh = {Biofilms/*growth & development ; DNA, Bacterial/chemistry ; DNA, Environmental/*chemistry ; Extracellular Polymeric Substance Matrix/chemistry/*genetics ; G-Quadruplexes ; Ionic Liquids/chemistry ; Magnetic Resonance Spectroscopy ; Pseudomonas aeruginosa/genetics/*physiology ; }, abstract = {Extracellular DNA, or eDNA, is recognised as a critical biofilm component; however, it is not understood how it forms networked matrix structures. Here, we isolate eDNA from static-culture Pseudomonas aeruginosa biofilms using ionic liquids to preserve its biophysical signatures of fluid viscoelasticity and the temperature dependency of DNA transitions. We describe a loss of eDNA network structure as resulting from a change in nucleic acid conformation, and propose that its ability to form viscoelastic structures is key to its role in building biofilm matrices. Solid-state analysis of isolated eDNA, as a proxy for eDNA structure in biofilms, reveals non-canonical Hoogsteen base pairs, triads or tetrads involving thymine or uracil, and guanine, suggesting that the eDNA forms G-quadruplex structures. These are less abundant in chromosomal DNA and disappear when eDNA undergoes conformation transition. We verify the occurrence of G-quadruplex structures in the extracellular matrix of intact static and flow-cell biofilms of P. aeruginosa, as displayed by the matrix to G-quadruplex-specific antibody binding, and validate the loss of G-quadruplex structures in vivo to occur coincident with the disappearance of eDNA fibres. Given their stability, understanding how extracellular G-quadruplex structures form will elucidate how P. aeruginosa eDNA builds viscoelastic networks, which are a foundational biofilm property.}, } @article {pmid33741610, year = {2021}, author = {Nowak, J and Visnovsky, SB and Pitman, AR and Cruz, CD and Palmer, J and Fletcher, GC and Flint, S}, title = {Biofilm Formation by Listeria monocytogenes 15G01, a Persistent Isolate from a Seafood-Processing Plant, Is Influenced by Inactivation of Multiple Genes Belonging to Different Functional Groups.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {10}, pages = {}, pmid = {33741610}, issn = {1098-5336}, mesh = {Bacterial Proteins/*genetics ; *Biofilms ; *Food Handling ; Genes, Bacterial ; Listeria monocytogenes/genetics/*physiology ; Mutation ; New Zealand ; *Seafood ; }, abstract = {Listeria monocytogenes is a ubiquitous foodborne pathogen that results in a high rate of mortality in sensitive and immunocompromised people. Contamination of food with L. monocytogenes is thought to occur during food processing, most often as a result of the pathogen producing a biofilm that persists in the environment and acting as the source for subsequent dispersal of cells onto food. A survey of seafood-processing plants in New Zealand identified the persistent strain 15G01, which has a high capacity to form biofilms. In this study, a transposon library of L. monocytogenes 15G01 was screened for mutants with altered biofilm formation, assessed by a crystal violet assay, to identify genes involved in biofilm formation. This screen identified 36 transposants that showed a significant change in biofilm formation compared to the wild type. The insertion sites were in 27 genes, 20 of which led to decreased biofilm formation and seven to an increase. Two insertions were in intergenic regions. Annotation of the genes suggested that they are involved in diverse cellular processes, including stress response, autolysis, transporter systems, and cell wall/membrane synthesis. Analysis of the biofilms produced by the transposants using scanning electron microscopy and fluorescence microscopy showed notable differences in the structure of the biofilms compared to the wild type. In particular, inactivation of uvrB and mltD produced coccoid-shaped cells and elongated cells in long chains, respectively, and the mgtB mutant produced a unique biofilm with a sandwich structure which was reversed to the wild-type level upon magnesium addition. The mltD transposant was successfully complemented with the wild-type gene, whereas the phenotypes were not or only partially restored for the remaining mutants.IMPORTANCE The major source of contamination of food with Listeria monocytogenes is thought to be due to biofilm formation and/or persistence in food-processing plants. By establishing as a biofilm, L. monocytogenes cells become harder to eradicate due to their increased resistance to environmental threats. Understanding the genes involved in biofilm formation and their influence on biofilm structure will help identify new ways to eliminate harmful biofilms in food processing environments. To date, multiple genes have been identified as being involved in biofilm formation by L. monocytogenes; however, the exact mechanism remains unclear. This study identified four genes associated with biofilm formation by a persistent strain. Extensive microscopic analysis illustrated the effect of the disruption of mgtB, clsA, uvrB, and mltD and the influence of magnesium on the biofilm structure. The results strongly suggest an involvement in biofilm formation for the four genes and provide a basis for further studies to analyze gene regulation to assess the specific role of these biofilm-associated genes.}, } @article {pmid33741166, year = {2021}, author = {Selover, B and Waite-Cusic, JG}, title = {Growth potential and biofilm development of nonstarter bacteria on surfaces exposed to a continuous whey stream.}, journal = {Journal of dairy science}, volume = {104}, number = {6}, pages = {6508-6515}, doi = {10.3168/jds.2020-19837}, pmid = {33741166}, issn = {1525-3198}, mesh = {Animals ; Bacteria ; Biofilms ; Colony Count, Microbial/veterinary ; *Rivers ; Stainless Steel ; *Whey ; }, abstract = {Commercial Cheddar cheese production uses an automated, continuous production system that provides favorable conditions for specific undesirable bacterial subpopulations in certain sections of the processing system. The draining and matting conveyor (DMC) is a large, fully enclosed series of conveyor belts that separates curd and whey on the first drain belt and supports the cheddaring process in subsequent sections. In a previous study, we demonstrated that coliforms increase in the draining section of the DMC (pH 6.0-6.3, 36°C) over a typical 18-h production shift and can lead to detectable coliforms in finished cheese. Sampling at the commercial plant indicated 2 sources of very low levels of coliforms: (1) subpasteurized whey and curd entering the DMC and (2) surfaces in the DMC after sanitation. Mitigation of these sources would require different approaches. The aim of this study was to investigate whether naturally low levels of coliforms in whey could increase in the bulk liquid and attach to different surface materials within 18 h. A laboratory-scale system was created to mimic the conditions of the initial draining section of the DMC and consisted of single-pass, naturally contaminated whey (pH 6.3, 35°C) flowing through a bioreactor (1.11 L/h) containing coupons of surface types found in the DMC (stainless steel and polypropylene). Whey inside the bioreactor chamber and surface coupons were enumerated for bacterial subpopulations on selective media for planktonic and attached bacteria, respectively, at 0, 12, 15, and 18 h. Bacterial isolates were identified by 16S rDNA sequencing. Nonstarter bacteria present in the whey at 0 h included coliforms (Enterobacter), Pseudomonas, and Acinetobacter (0.80, 2.55, and 2.32 log cfu/mL, respectively), with each increasing significantly in whey (6.18, 7.00, and 5.89 log cfu/mL) and on coupons (5.20, 6.85, and 5.29 log cfu/cm[2], respectively) after 18 h in the continuous flowing system. Scanning electron microscopy confirmed bacterial attachment on both surfaces, with early biofilm development evident on polypropylene coupons by 18 h. Results from this laboratory-scale study demonstrated that naturally low levels of coliforms entering the DMC in the whey could replicate within the conditions of the draining section of the DMC to the levels found in the commercial production environment.}, } @article {pmid33740976, year = {2021}, author = {Sionov, RV and Tsavdaridou, D and Aqawi, M and Zaks, B and Steinberg, D and Shalish, M}, title = {Tooth mousse containing casein phosphopeptide-amorphous calcium phosphate prevents biofilm formation of Streptococcus mutans.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {136}, pmid = {33740976}, issn = {1472-6831}, mesh = {Biofilms ; Calcium Phosphates ; *Caseins/pharmacology ; Child ; Humans ; Phosphopeptides ; *Streptococcus mutans ; Tooth Remineralization ; }, abstract = {BACKGROUND: Streptococcus mutans is a common cariogenic bacterium in the oral cavity involved in plaque formation. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has been introduced into tooth mousse to encourage remineralization of dental enamel. The aim of this research was to study the effect of tooth mousse containing CPP-ACP (GC Tooth Mousse®) or CPP-ACP with 0.2% fluoride (CPP-ACPF; GC Tooth Mousse Plus®; GCP) on S. mutans planktonic growth and biofilm formation.

METHODS: S. mutans was cultivated in the presence of different dilutions of the tooth mousse containing CPP-ACP or CPP-ACPF, and the planktonic growth was determined by ATP viability assay and counting colony-forming units (CFUs). The resulting biofilms were examined by crystal violet staining, MTT metabolic assay, confocal laser scanning microscopy (CLSM), and scanning electron microscope (SEM).

RESULTS: The CPP-ACP tooth mousse (GC) at a dilution of 5-50 mg/ml (0.5-5%) did not inhibit planktonic growth, and even increased the ATP content and the number of viable bacteria after a 24 h incubation. The same was observed for the CPP-ACPF tooth mousse (GCP), except for the higher concentrations (25 and 50 mg/ml) that led to a drop in the bacterial count. Importantly, both compounds significantly decreased S. mutans biofilm formation at dilutions as low as 1.5-3 mg/ml. 12.5 mg/ml GC and 6.25 mg/ml GCP inhibited biofilm formation by 90% after 4 h. After 24 h, the MBIC90 was 6.25 mg/ml for both. CLSM images confirmed the strong inhibitory effect GC and GCP had on biofilm formation when using 5 mg/ml tooth mousse. SEM images of those bacteria that managed to form biofilm in the presence of 5 mg/ml tooth mousse, showed alterations in the bacterial morphology, where the streptococci appear 25-30% shorter on the average than the control bacteria.

CONCLUSION: Our data show that the tooth mousse containing CPP-ACP reduces biofilm formation of the cariogenic bacterium S. mutans without killing the bacteria. The use of natural substances which inhibit biofilm development without killing the bacteria, has therapeutic benefits, especially in orthodontic pediatric patients.}, } @article {pmid33740161, year = {2021}, author = {Matthes, R and Jablonowski, L and Holtfreter, B and Pink, C and Kocher, T}, title = {Enzymatic biofilm destabilisation to support mechanical cleansing of inserted dental implant surfaces: an in-vitro pilot study.}, journal = {Odontology}, volume = {109}, number = {4}, pages = {780-791}, pmid = {33740161}, issn = {1618-1255}, support = {MA 7274/1-1//German Research Foundation/ ; }, mesh = {Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis ; Pilot Projects ; Surface Properties ; }, abstract = {Peri-implantitis is caused by microbial contamination and biofilm formation on the implant surface. To achieve re-osseointegration, the microbes must be completely removed from the surface. Adjunctive to mechanical cleaning, chemical treatment with enzymes or other substances could optimise the treatment outcome. Therefore, we investigated the efficacy of different enzymes, a surfactant, and a chelator in destabilising dental polymicrobial biofilm. The biofilm destabilising effect of the glycosidases α-amylase, dextranase, DispersinB[®], and lysozyme, as well as the proteinase subtilisin A, and the nuclease Benzonase[®], the chelator EDTA, and the surfactant cocamidopropyl betaine were investigated on biofilms, inoculated with plaque on rough titanium discs. The test and the control solutions were incubated for 15 min at 36 °C on biofilms, and loosened biofilm mass was removed by shear stress with a shaker. Fluorescence-stained biofilms were microscopically analysed. Acceptable cell tolerability concentrations of test substances were determined by the MTT (tetrazolium dye) assay on the MG-63 cell line. A statistically significant biofilm destabilising effect of 10% was shown with lysozyme (2500 µg/ml).}, } @article {pmid33739878, year = {2021}, author = {Guo, F and Guo, J and Cui, Y and Cao, X and Zhou, H and Su, X and Yang, B and Blackall, PJ and Xu, F}, title = {Exposure to Sublethal Ciprofloxacin Induces Resistance to Ciprofloxacin and Cross-Antibiotics, and Reduction of Fitness, Biofilm Formation, and Apx Toxin Secretion in Actinobacillus pleuropneumoniae.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {9}, pages = {1290-1300}, doi = {10.1089/mdr.2020.0348}, pmid = {33739878}, issn = {1931-8448}, mesh = {Actinobacillus pleuropneumoniae/*drug effects/genetics ; Animals ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/administration & dosage/*pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial/*drug effects/genetics ; Genes, Bacterial/drug effects ; Genotype ; Microbial Sensitivity Tests ; Phenotype ; Polymerase Chain Reaction ; Quinolones/administration & dosage/pharmacology ; Serogroup ; Swine ; Swine Diseases/microbiology ; }, abstract = {Actinobacillus pleuropneumoniae, the etiological agent of porcine pleuropneumonia, is increasingly resistant to antibiotics. However, little is known about the mechanisms of antibiotic resistance in this pathogen. In this study, we experimentally evolved the reference strain of both A. pleuropneumoniae serovar 1 and serovar 7, the most prevalent serovars worldwide, to quinolone resistance by sequential exposure to subinhibitory concentrations of ciprofloxacin. The adaptive ciprofloxacin-resistant mutants of A. pleuropneumoniae serovar 1 and serovar 7 had a minimum inhibitory concentration (MIC) increment from 0.004 to 1 or 2 μg/mL, respectively. Adaptation to ciprofloxacin was shown to confer quinolone resistance with a 32- to 512-fold increase (serovars 1 and 7, respectively) as well as cross-resistance to ampicillin with an increased MIC by 16,384- and 64-fold (serovars 1 and 7, respectively). The genetic analysis of quinolone resistance-determining region mutations showed that substitutions occurred in gyrA (S83A) and parC (D84N) of serovar 1, and gyrA (D87N) of serovar 7. The ciprofloxacin-resistant mutants showed significantly reduced bacterial fitness. The mutants also showed changes in efflux ability and biofilm formation. Notably, the transcription and secretion levels of Apx toxins were dramatically reduced in ciprofloxacin-resistant mutants compared with their wild-type strains. Altogether, these results demonstrated marked phenotypic changes in ciprofloxacin-resistant mutants of A. pleuropneumoniae. The results stress the need for further studies on the impact of both the genotypic and phenotypic characteristics of A. pleuropneumoniae following exposure to subinhibitory concentrations of antibiotics.}, } @article {pmid33739867, year = {2021}, author = {Zaman Vaziri, A and Khodaie, R and Narimisa, N and Sholeh, M}, title = {Letter to the Editor: Comments on the Published Meta-Analysis of Biofilm Formation, Antibiotic Resistance Pattern, and Biofilm-Related Genes in Pseudomonas aeruginosa Isolated from Clinical Samples.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {9}, pages = {1301}, doi = {10.1089/mdr.2020.0580}, pmid = {33739867}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Drug Resistance, Microbial/drug effects ; Humans ; *Pseudomonas Infections/drug therapy ; *Pseudomonas aeruginosa/drug effects/genetics ; }, } @article {pmid33737921, year = {2021}, author = {Agius, JE and Phalen, DN and Rose, K and Eden, JS}, title = {Genomic Insights Into the Pathogenicity of a Novel Biofilm-Forming Enterococcus sp. Bacteria (Enterococcus lacertideformus) Identified in Reptiles.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {635208}, pmid = {33737921}, issn = {1664-302X}, abstract = {Whole genome analysis of a novel species of enterococci, Enterococcus lacertideformus, causing multi-systemic and invariably fatal disease in critically endangered Christmas Island reptiles was undertaken to determine the genetic elements and potential mechanisms conferring its pathogenic nature, biofilm-forming capabilities, immune recognition avoidance, and inability to grow in vitro. Comparative genomic analyses with related and clinically significant enterococci were further undertaken to infer the evolutionary history of the bacterium and identify genes both novel and absent. The genome had a G + C content of 35.1%, consisted of a circular chromosome, no plasmids, and was 2,419,934 bp in length (2,321 genes, 47 tRNAs, and 13 rRNAs). Multi-locus sequence typing (MLST), and single nucleotide polymorphism (SNP) analysis of multiple E. lacertideformus samples revealed they were effectively indistinguishable from one another and highly clonal. E. lacertideformus was found to be located within the Enterococcus faecium species clade and was closely related to Enterococcus villorum F1129D based on 16S rDNA and MLST house-keeping gene analysis. Antimicrobial resistance (DfreE, EfrB, tetM, bcrRABD, and sat4) and virulence genes (Fss3 and ClpP), and genes conferring tolerance to metals and biocides (n = 9) were identified. The detection of relatively few genes encoding antimicrobial resistance and virulence indicates that this bacterium may have had no exposure to recently developed and clinically significant antibiotics. Genes potentially imparting beneficial functional properties were identified, including prophages, insertion elements, integrative conjugative elements, and genomic islands. Functional CRISPR-Cas arrays, and a defective prophage region were identified in the genome. The study also revealed many genomic loci unique to E. lacertideformus which contained genes enriched in cell wall/membrane/envelop biogenesis, and carbohydrate metabolism and transport functionality. This finding and the detection of putative enterococcal biofilm determinants (EfaAfs, srtC, and scm) may underpin the novel biofilm phenotype observed for this bacterium. Comparative analysis of E. lacertideformus with phylogenetically related and clinically significant enterococci (E. villorum F1129D, Enterococcus hirae R17, E. faecium AUS0085, and Enterococcus faecalis OG1RF) revealed an absence of genes (n = 54) in E. lacertideformus, that encode metabolic functionality, which potentially hinders nutrient acquisition and/or utilization by the bacterium and precludes growth in vitro. These data provide genetic insights into the previously determined phenotype and pathogenic nature of the bacterium.}, } @article {pmid33736863, year = {2022}, author = {Araujo, CB and Ribeiro, AB and Fortes, CV and Bueno, FL and De Wever, B and Oliveira, VC and Macedo, AP and Paranhos, HFO and da Silva, CHL}, title = {Effect of local hygiene protocols on denture-related stomatitis, biofilm, microbial load, and odor: A randomized controlled trial.}, journal = {The Journal of prosthetic dentistry}, volume = {128}, number = {4}, pages = {664-673}, doi = {10.1016/j.prosdent.2020.12.018}, pmid = {33736863}, issn = {1097-6841}, mesh = {Humans ; Denture Cleansers/therapeutic use/pharmacology ; *Stomatitis, Denture/drug therapy ; Sodium Hypochlorite/therapeutic use/pharmacology ; Odorants ; *Triclosan/therapeutic use/pharmacology ; Biofilms ; Candida albicans ; Hygiene ; Colony Count, Microbial ; Randomized Controlled Trials as Topic ; }, abstract = {STATEMENT OF PROBLEM: Denture stomatitis affects complete denture wearers and is frequently treated with antifungals drugs, as well as treating the denture with sodium hypochlorite. Whether the limitations of these treatments can be overcome with local hygiene protocols that do not damage the denture materials or adversely affect the patient is unclear.

PURPOSE: The purpose of this randomized controlled trial was to evaluate the effect of denture hygiene protocols on complete denture wearers with denture stomatitis.

MATERIAL AND METHODS: For this randomized, double-blind controlled clinical trial, 108 participants were assigned to parallel groups: 0.25% sodium hypochlorite (positive control) 0.15% Triclosan, denture cleaning tablets, or denture cleaning tablets plus gingival cleaning tablets. The participants were instructed to brush the dentures and the palate and immerse the denture in the solutions. The outcomes of denture stomatitis remission, biofilm removal, decrease of microbial load (colony-forming units), and odor level of the mouth and denture were measured at baseline and after 10 days. Descriptive analyses were used for sociodemographic characterization of the participants; the Pearson chi-square test was used to compare participant frequency with different degrees of denture stomatitis. The data were not normally distributed (Shapiro-Wilks test) or homogeneous (Levene test). So, the Kruskal-Wallis and Dunn post hoc tests and Wilcoxon test were used to compare the effects of solutions and time on the variables (α=.05).

RESULTS: The frequency of the highest to lowest denture stomatitis scores was significantly different for the 0.15% Triclosan and denture cleaning tablets groups. No significant difference was found among the groups in terms of denture stomatitis scores, biofilm, or colony-forming unit count of Candida spp. or C. albicans and S. mutans; a significant reduction was found in these parameters. The 0.25% sodium hypochlorite and 0.15% Triclosan treatments caused a significant reduction in Gram-negative microorganisms; these 2 protocols, and the denture cleaning tablets showed a significant reduction in Staphylococcus spp.; all protocols had similar effects. Only the S. mutans count of the palate decreased after 10 days. The odor level of the mouth and the denture was not significantly different (P=.778).

CONCLUSIONS: The evaluated protocols can be recommended for the hygiene of complete dentures, since they were effective for all the variables studied.}, } @article {pmid33735944, year = {2021}, author = {Patel, B and Mishra, S and Priyadarsini, IK and Vavilala, SL}, title = {Elucidating the anti-biofilm and anti-quorum sensing potential of selenocystine against respiratory tract infections causing bacteria: in vitro and in silico studies.}, journal = {Biological chemistry}, volume = {402}, number = {7}, pages = {769-783}, doi = {10.1515/hsz-2020-0375}, pmid = {33735944}, issn = {1437-4315}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Cystine/*analogs & derivatives/chemistry/pharmacology ; Dose-Response Relationship, Drug ; Humans ; Klebsiella pneumoniae/*drug effects/growth & development ; Microbial Sensitivity Tests ; Organoselenium Compounds/chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects/growth & development ; Quorum Sensing/drug effects ; Respiratory Tract Infections/*drug therapy/microbiology ; }, abstract = {Bacteria are increasingly relying on biofilms to develop resistance to antibiotics thereby resulting in their failure in treating many infections. In spite of continuous research on many synthetic and natural compounds, ideal anti-biofilm molecule is still not found thereby warranting search for new class of molecules. The current study focuses on exploring anti-biofilm potential of selenocystine against respiratory tract infection (RTI)-causing bacteria. Anti-bacterial and anti-biofilm assays demonstrated that selenocystine inhibits the growth of bacteria in their planktonic state, and formation of biofilms while eradicating preformed-biofilm effectively. Selenocystine at a MIC50 as low as 42 and 28 μg/mL effectively inhibited the growth of Klebsiella pneumonia and Pseudomonas aeruginosa. The antibacterial effect is further reconfirmed by agar cup diffusion assay and growth-kill assay. Selenocystine showed 30-60% inhibition of biofilm formation in K. pneumonia, and 44-70% in P. aeruginosa respectively. It also distorted the preformed-biofilms by degrading the eDNA component of the Extracellular Polymeric Substance matrix. Molecular docking studies of selenocystine with quorum sensing specific proteins clearly showed that through the carboxylic acid moiety it interacts and inhibits the protein function, thereby confirming its anti-biofilm potential. With further validation selenocystine can be explored as a potential candidate for the treatment of RTIs.}, } @article {pmid33735634, year = {2021}, author = {Caro-Lara, L and Ramos-Moore, E and Vargas, IT and Walczak, M and Fuentes, C and Gómez, AV and Barrera, NP and Castillo, J and Pizarro, G}, title = {Initial adhesion suppression of biofilm-forming and copper-tolerant bacterium Variovorax sp. on laser microtextured copper surfaces.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {202}, number = {}, pages = {111656}, doi = {10.1016/j.colsurfb.2021.111656}, pmid = {33735634}, issn = {1873-4367}, mesh = {Bacteria ; Bacterial Adhesion ; *Biofilms ; *Copper/pharmacology ; Lasers ; Surface Properties ; }, abstract = {The growth of detrimental biofilms on metal surfaces affects their structural performance and lifespan. Microtopographic texturization has emerged as an approach to suppress biofilm growth by preventing the initial stages of bacterial adhesion. This work studies the effects of linear pattern copper texturization on the initial adhesion steps of the biofilm-forming and copper-resistant bacterium Variovorax sp. Linear patterns with 4.7, 6.8, 14, and 18 μm periodicity were produced by direct laser interference patterning (DLIP) on copper coupons. Surface features were characterized by microscopic and spectroscopic techniques, and bacterial adhesion behavior was characterized by epifluorescence microscopy and functionalization of atomic force microscopy tips. We found a periodicity of 4.7 μm as the most efficient pattern to suppress Variovorax sp. initial adhesion by 31.1 % with respect to the nontextured surface. Preferential settlement in hummocks over hollows was observed for patterns with 14 and 18 μm periodicity, with adhesion events showing higher frequency in these topographies than patterns with periodicities of 4.7 and 6.8 μm. Our results highlight an understanding of the initial bacteria-copper adhesion and settlement behavior, thus contributing to the potential development of innocuous strategies for controlling biofilm growth on copper-based materials.}, } @article {pmid33735072, year = {2021}, author = {Huiszoon, RC and Han, J and Chu, S and Stine, JM and Beardslee, LA and Ghodssi, R}, title = {Integrated System for Bacterial Detection and Biofilm Treatment on Indwelling Urinary Catheters.}, journal = {IEEE transactions on bio-medical engineering}, volume = {68}, number = {11}, pages = {3241-3249}, doi = {10.1109/TBME.2021.3066995}, pmid = {33735072}, issn = {1558-2531}, mesh = {Bacteria ; Biofilms ; *Catheters, Indwelling/adverse effects ; Urinary Catheterization/adverse effects ; *Urinary Catheters/adverse effects ; }, abstract = {GOAL: This work introduces an integrated system incorporated seamlessly with a commercial Foley urinary catheter for bacterial growth sensing and biofilm treatment.

METHODS: The system is comprised of flexible, interdigitated electrodes incorporated with a urinary catheter via a 3D-printed insert for impedance sensing and bioelectric effect-based treatment. Each of the functions were wirelessly controlled using a custom application that provides a user-friendly interface for communicating with a custom PCB via Bluetooth to facilitate implementation in practice.

RESULTS: The integrated catheter system maintains the primary functions of indwelling catheters - urine drainage, balloon inflation - while being capable of detecting the growth of Escherichia coli, with an average decrease in impedance of 13.0% after 24 hours, tested in a newly-developed simulated bladder environment. Furthermore, the system enables bioelectric effect-based biofilm reduction, which is performed by applying a low-intensity electric field that increases the susceptibility of biofilm bacteria to antimicrobials, ultimately reducing the required antibiotic dosage.

CONCLUSION: Overall, this modified catheter system represents a significant step forward for catheter-associated urinary tract infection (CAUTI) management using device-based approaches, integrating flexible electrodes with an actual Foley catheter along with the control electronics and mobile application.

SIGNIFICANCE: CAUTIs, exacerbated by the emergence of antibiotic-resistant pathogens, represent a significant challenge as one of the most prevalent healthcare-acquired infections. These infections are driven by the colonization of indwelling catheters by bacterial biofilms.}, } @article {pmid33732226, year = {2021}, author = {Ma, D and Gu, H and Shi, Y and Huang, H and Sun, D and Hu, Y}, title = {Edwardsiella piscicida YefM-YoeB: A Type II Toxin-Antitoxin System That Is Related to Antibiotic Resistance, Biofilm Formation, Serum Survival, and Host Infection.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {646299}, pmid = {33732226}, issn = {1664-302X}, abstract = {The emergence of drug resistant bacteria is a tricky and confronted problem in modern medicine, and one of important reasons is the widespread of toxin-antitoxin (TA) systems in pathogenic bacteria. Edwardsiella piscicida (also known as E. tarda) is the leading pathogen threatening worldwide fresh and seawater aquaculture industries and has been considered as a model organism for studying intracellular and systemic infections. However, the role of type II TA systems are completely unknown in aquatic pathogenic bacteria. In this study, we identified and characterized a type II TA system, YefM-YoeB, of E. piscicida, where YefM is the antitoxin and YoeB is the toxin. yefM and yoeB are co-expressed in a bicistronic operon. When expressed in E. coli, YoeB cause bacterial growth arrest, which was restored by the addition of YefM. To investigate the biological role of the TA system, two markerless yoeB and yefM-yoeB in-frame mutant strains, TX01ΔyoeB and TX01ΔyefM-yoeB, were constructed, respectively. Compared to the wild strain TX01, TX01ΔyefM-yoeB exhibited markedly reduced resistance against oxidative stress and antibiotic, and markedly reduced ability to form persistent bacteria. The deletion of yefM-yoeB enhanced the bacterial ability of high temperature tolerance, biofilm formation, and host serum resistance, which is the first study about the relationship between type II TA system and serum resistance. In vitro infection experiment showed that the inactivation of yefM-yoeB greatly enhanced bacterial capability of adhesion in host cells. Consistently, in vivo experiment suggested that the yefM-yoeB mutation had an obvious positive effect on bacteria dissemination of fish tissues and general virulence. Introduction of a trans-expressed yefM-yoeB restored the virulence of TX01ΔyefM-yoeB. These findings suggest that YefM-YoeB is involved in responding adverse circumstance and pathogenicity of E. piscicida. In addition, we found that YefM-YoeB negatively autoregulated the expression of yefM-yoeB and YefM could directly bind with own promoter. This study provides first insights into the biological activity of type II TA system YefM-YoeB in aquatic pathogenic bacteria and contributes to understand the pathogenesis of E. piscicida.}, } @article {pmid33732076, year = {2021}, author = {Zaynab, M and Chen, H and Chen, Y and Ouyang, L and Yang, X and Hu, Z and Li, S}, title = {Signs of biofilm formation in the genome of Labrenzia sp. PO1.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {3}, pages = {1900-1912}, pmid = {33732076}, issn = {1319-562X}, abstract = {Labrenzia sp. are important components of marine ecology which play a key role in biochemical cycling. In this study, we isolated the Labrenzia sp. PO1 strain capable of forming biofilm, from the A. sanguinea culture. Growth analysis revealed that strain reached a logarithmic growth period at 24 hours. The whole genome of 6.21813 Mb of Labrezia sp. PO1 was sequenced and assembled into 15 scaffolds and 16 contigs, each with minimum and maximum lengths of 644 and 1,744,114 Mb. A total of 3,566 genes were classified into five pathways and 31 pathway groups. Of them, 521 genes encoded biofilm formation proteins, quorum sensing (QS) proteins, and ABC transporters. Gene Ontology annotation identified 49,272 genes that were involved in biological processes (33,425 genes), cellular components (7,031genes), and molecular function (7,816 genes). We recognised genes involved in bacterial quorum sensing, attachment, motility, and chemotaxis to investigate bacteria's ability to interact with the diatom phycosphere. As revealed by KEGG pathway analysis, several genes encoding ABC transporters exhibited a significant role during the growth and development of Labrenzia sp. PO1, indicating that ABC transporters may be involved in signalling pathways that enhance growth and biofilm formation.}, } @article {pmid33732058, year = {2021}, author = {Rajivgandhi, GN and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Kanisha, CC and Ramachandran, G and Manoharan, N and Alanzi, KF}, title = {Identification of carbapenems resistant genes on biofilm forming K. pneumoniae from urinary tract infection.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {3}, pages = {1750-1756}, pmid = {33732058}, issn = {1319-562X}, abstract = {The multi-drug resistant effect of the Gram negative bacteria K. pneumoniae was identified by disc diffusion method using specific UTI panel discs of Kleb 1 HX077 and Kleb 2 HX090 HEXA. Among the multi-drug resistant bacteria, the carbapenem resistant (CR) effect of the K. pneumoniae was screened by specific carbapenem detection antibiotics of HEXA HX066 and HX0103 HEXA by disc diffusion method. In addition, the effective antibiotics were further performed against K. pneumoniae by minimum inhibition concentration method. Further, the carbapenemase genes of VIM 1 and IMP 1 were detected from the isolated strains by multiplex PCR method. Furthermore, the biofilm forming ability of selected carbapenem resistant K. pneumoniae was initially identified by tissue culture plate method and confirmed by exopolysaccharide arrest ability of congo red agar assay. Finally, our result was proved that the identified K. pneumoniae is carbapenemase producing strain, and its virulence was extended with strong biofilm formation.}, } @article {pmid33732047, year = {2021}, author = {Nguyen, PTM and Nguyen, MTH and Bolhuis, A}, title = {Inhibition of biofilm formation by alpha-mangostin loaded nanoparticles against Staphylococcus aureus.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {3}, pages = {1615-1621}, pmid = {33732047}, issn = {1319-562X}, abstract = {This study aimed to investigate the antibiofilm activity of alpha-mangostin (AMG) loaded nanoparticles (nanoAMG) against Staphylococcus aureus, including the methicillin-resistant strain MRSA252. The results indicated that treatment with 24 μmol/L nanoAMG inhibited the formation of biofilm biomass by 53-62%, compared to 40-44% for free AMG (p < 0.05). At 48 μmol/L, biofilms in all nanoAMG treated samples were nearly fully disrupted for the two tested strains, MRSA252 and the methicillin-sensitive strain NCTC6571. That concentration resulted in killing of biofilm cells. A lower concentration of 12 µmol/L nanoAMG inhibited initial adherence of the two bacterial strains by > 50%. In contrast, activity of nanoAMG was limited on preformed mature biofilms, which at a concentration of 48 µmol/L were reduced only by 27% and 22% for NCTC6571 and MRSA252, respectively. The effects of AMG or nanoAMG on the expression of biofilm-related genes showed some noticeable differences between the two strains. For instance, the expression level of ebpS was downregulated in MRSA252 and upregulated in NCTC6571 when those strains were treated with either AMG or nanoAMG. In contrast, the expression of fnbB was down regulated in NCTC6571, while it was up-regulated in the MRSA252. The expression of other biofilm-related genes (icaC, clfB and fnbA) was down regulated in both strains. In conclusion, our results suggest that AMG coated nanoparticles had enhanced biological activity as compared to free AMG, indicating that nanoAMG could be a new and promising inhibitor of biofilm formation to tackle S. aureus, including strains that are resistant to multiple antibiotics.}, } @article {pmid33731698, year = {2021}, author = {Abraham, S and Kaufman, Y and Perreault, F and Young, R and Bar-Zeev, E}, title = {Bursting out: linking changes in nanotopography and biomechanical properties of biofilm-forming Escherichia coli to the T4 lytic cycle.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {26}, pmid = {33731698}, issn = {2055-5008}, support = {R35 GM136396/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Bacteriolysis ; Bacteriophage T4/*pathogenicity ; Biofilms/*growth & development ; Biomechanical Phenomena ; Escherichia coli/*physiology/ultrastructure/virology ; Microscopy, Atomic Force ; }, abstract = {The bacteriophage infection cycle has been extensively studied, yet little is known about the nanostructure and mechanical changes that lead to bacterial lysis. Here, atomic force microscopy was used to study in real time and in situ the impact of the canonical phage T4 on the nanotopography and biomechanics of irreversibly attached, biofilm-forming E. coli cells. The results show that in contrast to the lytic cycle in planktonic cells, which ends explosively, anchored cells that are in the process of forming a biofilm undergo a more gradual lysis, developing distinct nanoscale lesions (~300 nm in diameter) within the cell envelope. Furthermore, it is shown that the envelope rigidity and cell elasticity decrease (>50% and >40%, respectively) following T4 infection, a process likely linked to changes in the nanostructure of infected cells. These insights show that the well-established lytic pathway of planktonic cells may be significantly different from that of biofilm-forming cells. Elucidating the lysis paradigm of these cells may advance biofilm removal and phage therapeutics.}, } @article {pmid33731542, year = {2021}, author = {Takahashi, M and Matin, K and Matsui, N and Shimizu, M and Tsuda, Y and Uchinuma, S and Hiraishi, N and Nikaido, T and Tagami, J}, title = {Effects of silver diamine fluoride preparations on biofilm formation of Streptococcus mutans.}, journal = {Dental materials journal}, volume = {40}, number = {4}, pages = {911-917}, doi = {10.4012/dmj.2020-341}, pmid = {33731542}, issn = {1881-1361}, mesh = {Animals ; Biofilms ; Cattle ; *Dental Caries ; Fluorides, Topical/pharmacology ; Quaternary Ammonium Compounds ; Silver Compounds/pharmacology ; *Streptococcus mutans ; }, abstract = {Effects of silver diamine fluoride preparations (SDFs) on cariogenic biofilm formation on root dentin (RD) were investigated. Streptococcus mutans (S. mutans) biofilms were formed on bovine RD blocks coated with one of three the SDFs (38%-SDF, 3.8%-SDF and 35%-SDF+potassium-iodide; SDF+KI) and a non-coated Control which were quantified (spectrometric-measurement) and thickness measured (optical coherence tomography) after 20 h. Bacterial viability test (BacLight) and biofilm-morphometry (SEM) of 2 h biofilms were also performed. The amounts of biofilms (bacteria and water insoluble glucan) and the thickness of biofilm were minimum on 38%-SDF specimen; 3.8%-SDF and SDF+KI had significantly more than that, but had significantly less than Control (p<0.05). Most S. mutans cells found dead and morphology damaged by 38%-SDF. Some dead bacteria and remarkably damaged biofilms were observed in case of 3.8%-SDF and SDF+KI. Inhibition potential of 3.8%-SDF and SDF+KI on S. mutans biofilm formation is almost similar, although not equivalent to 38%-SDF.}, } @article {pmid33730946, year = {2021}, author = {Reis, MP and de Paula, RS and Reis, ALM and Souza, CCE and Júnior, RBO and Ferreira, JA and Mota, HR and de Carvalho, MD and Jorge, EC and Cardoso, AV and Nascimento, AMA}, title = {Microbial composition of a hydropower cooling water system reveals thermophilic bacteria with a possible role in primary biofilm formation.}, journal = {Biofouling}, volume = {37}, number = {2}, pages = {246-256}, doi = {10.1080/08927014.2021.1897790}, pmid = {33730946}, issn = {1029-2454}, mesh = {Archaea ; *Bacteria/genetics ; Biofilms ; Brazil ; *Water ; }, abstract = {Microfouling, ie biofilm formation on surfaces, can have an economic impact and requires costly maintenance in water-powered energy generation systems. In this study, the microbiota of a cooling system (filter and heat exchanger) in the Irapé hydroelectric power plant in Brazil was examined. The goal was to identify bacteria that could be targeted to more efficiently reduce biofilm formation. Two sampling campaigns were made corresponding to two well-defined seasons of the Brazilian Cerrado biome: the dry (campaign 1) and the wet (campaign 2). Microfouling communities varied considerably over time in samples obtained at different times after the last clearance of the heat exchanger. The thermophilic bacteria Meiothermus, Thermomonas and Symbiobacterium were exclusive and abundant in the microfouling of the heat exchanger in campaign 2, while methanotrophs and iron-reducing bacteria were abundant only in filter sediments. These findings could help to guide strategies for ecofriendly measures to reduce biofilm fouling in hydroelectric power plants, minimizing environmental and economic losses.}, } @article {pmid33730103, year = {2021}, author = {Salgado, BAB and Fabbri, S and Dickenson, A and Hasan, MI and Walsh, JL}, title = {Surface barrier discharges for Escherichia coli biofilm inactivation: Modes of action and the importance of UV radiation.}, journal = {PloS one}, volume = {16}, number = {3}, pages = {e0247589}, pmid = {33730103}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Atmospheric Pressure ; Biofilms/*drug effects/*radiation effects ; Escherichia coli/*drug effects/physiology/*radiation effects ; Microbial Viability/*drug effects/*radiation effects ; *Photons ; Plasma Gases/*pharmacology ; Polypropylenes/radiation effects ; Surface Properties/radiation effects ; *Ultraviolet Rays ; }, abstract = {Cold plasma generated in air at atmospheric pressure is an extremely effective antimicrobial agent, with proven efficacy against clinically relevant bacterial biofilms. The specific mode of bacterial inactivation is highly dependent upon the configuration of the plasma source used. In this study, the mode of microbial inactivation of a surface barrier discharge was investigated against Escherichia coli biofilms grown on polypropylene coupons. Different modes of exposure were considered and it was demonstrated that the long-lived reactive species created by the plasma are not solely responsible for the observed microbial inactivation. It was observed that a synergistic interaction occurs between the plasma generated long-lived reactive species and ultraviolet (UV) photons, acting to increase the antimicrobial efficacy of the approach by an order of magnitude. It is suggested that plasma generated UV is an important component for microbial inactivation when using a surface barrier discharge; however, it is not through the conventional pathway of direct DNA damage, rather through the synergistic interaction between liquid in the biofilm matrix and long-lived chemical species created by the discharge.}, } @article {pmid33729275, year = {2021}, author = {Santos, VRD and Valdez, RMA and Danelon, M and Souza, JAS and Caiaffa, KS and Delbem, ACB and Duque, C}, title = {Effect of S. mutans combinations with bifidobacteria/lactobacilli on biofilm and enamel demineralization.}, journal = {Brazilian oral research}, volume = {35}, number = {}, pages = {e030}, doi = {10.1590/1807-3107bor-2021.vol35.0030}, pmid = {33729275}, issn = {1807-3107}, mesh = {Animals ; Biofilms ; Cattle ; Cross-Sectional Studies ; *Dental Caries ; Dental Enamel ; Streptococcus mutans ; *Tooth Demineralization ; }, abstract = {The present study evaluated the ability of Bifidobacterium and Lactobacillus species associated with streptococci to increase insoluble extracellular polysaccharide (EPS) production and initial caries lesion progression. Bovine enamel blocks (n = 190; 4 mm x 4 mm) were prepared, selected according to initial surface hardness (SH), and divided into two groups: a) double combinations: S. mutans with Bifidobacterium or Lactobacillus, and b) triple combinations: S. mutans and S. sobrinus with Bifidobacterium or Lactobacillus species. The blocks were exposed to the bacterial associations for 7 days. Subsequently, quantity of EPS from biofilms and caries lesion depth were determined by means of colorimetric and cross-sectional enamel hardness (ΔKHN) analysis. The data were submitted to one-way analysis of variance, followed by the Bonferroni test (p < 0.05). S. mutans with B. animalis or B. dentium produced a higher quantity of EPS; S. mutans + B. animalis led to the highest ∆KHN. S. mutans + S. sobrinus + B. longum induced greater EPS and ∆KHN values. In conclusion, associations of B. animalis and B. longum with streptococci promoted EPS production and caries lesion progression.}, } @article {pmid33727555, year = {2021}, author = {Bisht, K and Moore, JL and Caprioli, RM and Skaar, EP and Wakeman, CA}, title = {Impact of temperature-dependent phage expression on Pseudomonas aeruginosa biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {22}, pmid = {33727555}, issn = {2055-5008}, support = {R01 AI145992/AI/NIAID NIH HHS/United States ; T32 AI112541/AI/NIAID NIH HHS/United States ; R01 AI138581/AI/NIAID NIH HHS/United States ; R15 GM128072/GM/NIGMS NIH HHS/United States ; P41 GM103391/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacteriophages/genetics/*metabolism ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Viral ; Hot Temperature ; Proteomics ; Pseudomonas aeruginosa/*physiology/virology ; Sequence Analysis, RNA/*methods ; Stress, Physiological ; Viral Proteins/genetics/*metabolism ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen that forms robust biofilms in the different niches it occupies. Numerous physiological adaptations are required as this organism shifts from soil or aquatic environments to a host-associated lifestyle. While many conditions differ between these niches, temperature shifts are a factor that can contribute to physiological stress during this transition. To understand how temperature impacts biofilm formation in this pathogen, we used proteomic and transcriptomic tools to elucidate physiological responses in environment-relevant vs. host-relevant temperatures. These studies uncovered differential expression of various proteins including a phage protein that is associated with the EPS matrix in P. aeruginosa. This filamentous phage was induced at host temperatures and was required for full biofilm-forming capacity specifically at human body temperature. These data highlight the importance of temperature shift in biofilm formation and suggest bacteriophage proteins could be a possible therapeutic target in biofilm-associated infections.}, } @article {pmid33724569, year = {2021}, author = {Abushahba, F and Gürsoy, M and Hupa, L and Närhi, TO}, title = {Effect of bioactive glass air-abrasion on Fusobacterium nucleatum and Porphyromonas gingivalis biofilm formed on moderately rough titanium surface.}, journal = {European journal of oral sciences}, volume = {129}, number = {3}, pages = {e12783}, doi = {10.1111/eos.12783}, pmid = {33724569}, issn = {1600-0722}, support = {//This study has not received any external funding/ ; }, mesh = {Biofilms ; *Fusobacterium nucleatum ; Microscopy, Electron, Scanning ; *Porphyromonas gingivalis ; Titanium ; }, abstract = {This aim of this study was to investigate the effects of three types of air-abrasion particles on dual-species biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis, both of which were cultured on sandblasted and acid-etched (SA) titanium discs. Out of 24 SA discs with biofilm, 18 were exposed to either air-abrasion using Bioglass 45S5 (45S5 BG; n = 6), novel zinc (Zn)-containing bioactive glass (Zn4 BG; n = 6), or inert glass (n = 6). The efficiency of biofilm removal was evaluated using scanning electron microscopy (SEM) imaging and culturing techniques. Air-abrasion using 45S5 BG or Zn4 BG demonstrated a significant decrease in the total number of viable bacteria compared to discs air-abraded with inert glass or intact biofilm without abrasion. Moreover, P. gingivalis could not be detected from SEM images nor culture plates after air-abrasion with 45S5 BG or Zn4 BG. The present study showed that air-abrasion with 45S5 or Zn4 bioactive glasses can successfully eradicate dual-biofilm of F. nucleatum and P. gingivalis from sandblasted and acid-etched titanium discs.}, } @article {pmid33724028, year = {2021}, author = {Zhao, L and Duan, F and Gong, M and Tian, X and Guo, Y and Jia, L and Deng, S}, title = {(+)-Terpinen-4-ol Inhibits Bacillus cereus Biofilm Formation by Upregulating the Interspecies Quorum Sensing Signals Diketopiperazines and Diffusing Signaling Factors.}, journal = {Journal of agricultural and food chemistry}, volume = {69}, number = {11}, pages = {3496-3510}, doi = {10.1021/acs.jafc.0c07826}, pmid = {33724028}, issn = {1520-5118}, mesh = {*Bacillus cereus ; Biofilms ; Diketopiperazines ; *Quorum Sensing ; Terpenes ; }, abstract = {Bacillus cereus is a Gram-positive endospore-forming foodborne pathogen that causes lethal food poisoning and significant economic losses, usually through biofilm- and endospore-induced recurrent cross- and postprocessing contamination. Due to the lack of critical inhibitory targets and control strategies, B. cereus biofilm contamination is a problem that urgently needs a solution. In this study, the antibacterial and antibiofilm activities of several natural potential bacterial quorum sensing (QS) interferers, a group of spice-originated monoterpenoids, were screened, and terpinen-4-ol effectively inhibited B. cereus growth and biofilm and spore germination with minimum growth inhibition and 50% biofilm inhibitory concentrations of 8 and 2 μmol/mL, respectively. FESEM/CLSM and phenotypic research illustrated that in addition to a decrease in the number of attached B. cereus cells, (+)-terpinen-4-ol also obviously reduced extracellular matrix synthesis, especially exopolysaccharides, and inhibited the swarming motility and protease activity of B. cereus. (+)-Terpinen-4-ol did not exert a significant effect on AI-2 signals in B. cereus. Accordingly, the B. cereus-produced interspecies QS signals diffusing signal factors (DSFs, C8-C15) and diketopiperazines (DKPs) were detected and identified here, which suppressed B. cereus biofilm formation in a concentration-dependent manner. (+)-Terpinen-4-ol significantly increased the levels of specific DSF and DKP signals in B. cereus and down-regulated the gene expression of some rpfB homologues in transcription level. Moreover, both DKPs and DSFs inhibited swarming motility and protease activity in B. cereus, while just the DSF signals 2-dodecenoic acid and 11-methyl-2-dodecenoic acid inhibited exopolysaccharide synthesis like (+)-terpinen-4-ol. In summary, B. cereus strains were found to produce nine DSF- and six DKP-type QS signaling molecules, which repressed B. cereus biofilm formation. (+)-Terpinen-4-ol was confirmed to be a promising antibacterial and antibiofilm agent against B. cereus upregulating DSFs and DKPs levels, and it could target the critical genes rpfB for DSFs turnover.}, } @article {pmid33721544, year = {2021}, author = {Kollmuss, M and Tolksdorf, K and Wuersching, SN and Hickel, R and Huth, KC}, title = {Effect of polyhexanide as antiseptic mouth rinse against oral pathogens in an in vitro biofilm model.}, journal = {Acta odontologica Scandinavica}, volume = {79}, number = {7}, pages = {506-513}, doi = {10.1080/00016357.2021.1899280}, pmid = {33721544}, issn = {1502-3850}, mesh = {Actinomyces ; Animals ; *Anti-Infective Agents, Local/pharmacology ; Biguanides ; Biofilms ; Chlorhexidine/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Mouthwashes ; Sheep ; Staphylococcus aureus ; Streptococcus mutans ; }, abstract = {OBJECTIVE: The aim of this study was to evaluate the anti-biofilm effect of polyhexanide mouth rinses against oral pathogens in vitro.

MATERIAL AND METHODS: Biofilms of Candida albicans, Streptococcus mutans, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, methicillin-resistant Staphylococcus aureus and Fusobacterium nucleatum were grown on 10 mm diameter hydroxyapatite discs for 5 days. Biofilms were exposed to test substances for 30 s (ProntOral, polyhexanide 0.15%, chlorhexidine 0.2%). Another test set simulating blood contamination in the oral cavity was performed by submerging the discs in defibrinated sheep blood prior to antimicrobial exposure. Biofilm mass was determined via crystal violet staining. The proliferation potency of the cells after antimicrobial exposure was evaluated by plating serially diluted suspensions from extracted biofilms on agar plates and determining the number of colony-forming units (CFU/ml). Mann-Whitney-U, Kruskal-Wallis and Dunn's test were used for statistical analyses.

RESULTS: Regardless of blood contamination ProntOral led to a significant reduction of biofilm mass in all strains. Chlorhexidine and polyhexanide reduced biofilm mass in five out of six strains and in only four strains after blood contamination. All agents significantly reduced CFU/ml from S. mutans, A. actinomycetemcomitans and F. nucleatum biofilms. C. albicans and S. aureus biofilms were only affected by ProntOral and polyhexanide. None of the antiseptics significantly reduced the CFU/ml for A. naeslundii biofilms. After blood contamination ProntOral and polyhexanide significantly reduced CFU/ml in all strains, whereas CHX tended to increase the CFU/ml.

CONCLUSIONS: Polyhexanide mouth rinses seem to be suitable disinfectants against oral pathogens without their anti-biofilm potential being impaired by blood.}, } @article {pmid33720927, year = {2021}, author = {Mamouei, Z and Singh, S and Lemire, B and Gu, Y and Alqarihi, A and Nabeela, S and Li, D and Ibrahim, A and Uppuluri, P}, title = {An evolutionarily diverged mitochondrial protein controls biofilm growth and virulence in Candida albicans.}, journal = {PLoS biology}, volume = {19}, number = {3}, pages = {e3000957}, pmid = {33720927}, issn = {1545-7885}, support = {R01 AI141202/AI/NIAID NIH HHS/United States ; R01 AI141794/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*genetics/growth & development ; Computational Biology/methods ; Fungal Proteins/metabolism ; Gene Expression Regulation, Fungal/genetics ; Genes, Mitochondrial/genetics/physiology ; Mitochondrial Proteins/*genetics/metabolism ; Models, Biological ; Phylogeny ; Virulence/genetics ; }, abstract = {A forward genetic screening approach identified orf19.2500 as a gene controlling Candida albicans biofilm dispersal and biofilm detachment. Three-dimensional (3D) protein modeling and bioinformatics revealed that orf19.2500 is a conserved mitochondrial protein, structurally similar to, but functionally diverged from, the squalene/phytoene synthases family. The C. albicans orf19.2500 is distinguished by 3 evolutionarily acquired stretches of amino acid inserts, absent from all other eukaryotes except a small number of ascomycete fungi. Biochemical assays showed that orf19.2500 is required for the assembly and activity of the NADH ubiquinone oxidoreductase Complex I (CI) of the respiratory electron transport chain (ETC) and was thereby named NDU1. NDU1 is essential for respiration and growth on alternative carbon sources, important for immune evasion, required for virulence in a mouse model of hematogenously disseminated candidiasis, and for potentiating resistance to antifungal drugs. Our study is the first report on a protein that sets the Candida-like fungi phylogenetically apart from all other eukaryotes, based solely on evolutionary "gain" of new amino acid inserts that are also the functional hub of the protein.}, } @article {pmid33720481, year = {2021}, author = {Abdelaziz, HA and Fouad, M and Mossad, M}, title = {Upgrading sequencing batch reactor using attached biofilm.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {9}, pages = {1700-1713}, doi = {10.1002/wer.1556}, pmid = {33720481}, issn = {1554-7531}, mesh = {Biofilms ; Bioreactors ; Sewage ; *Waste Disposal, Fluid ; *Water Purification ; }, abstract = {A conventional sequencing batch reactor (SBR) was upgraded using fixed biofilm carriers with a specific surface area around 18 m[2] m[-3] . The upgraded SBR was investigated to remove phenol from high strength wastewater operated under various operational conditions. The operational conditions used were variable volume exchange ratio (VER) up to 75%, hydraulic retention time (HRT) from (10.7-21.3 hr), aeration time (from 2 to 8 hr), and initial phenol concentration up to 600 mg L[-1] . It was found that the upgraded SBR increased the removal efficiencies of biological oxygen demand (BOD5), chemical oxygen demand (COD), and total suspended solids (TSS) by about 10% using high strength wastewater without phenol compared to SBR. Furthermore, the removal rate of phenol for the upgraded SBR was higher than conventional SBR by about 18% at 600 mg L[-] of initial phenol concentration under the same operational conditions. Compared to the conventional SBR, the upgraded version reduced the aeration step by 25% and achieved higher removal efficiency of phenol. Moreover, it reduced the excess sludge by about 23% and enhanced its properties by lowering the sludge volume index (SVI) by about 33%. PRACTITIONER POINTS: Upgrading conventional SBR by adding biofilm carriers is necessary for wastewater treatment with high strength wastewater. The upgraded SBR has a higher resistance toward phenol compound due to the presence of the attached biofilm. The upgraded SBR enhances sludge settling properties, decreases the amount of excess sludge, and also reduces the start-up period. The number of cycles per day by upgraded SBR was more than the conventional SBR by 15%. The upgraded SBR is an effective system and has good operational stability.}, } @article {pmid33719769, year = {2022}, author = {Shastry, RP and Kanekar, S and Pandial, AS and Rekha, PD}, title = {Isoeugenol suppresses multiple quorum sensing regulated phenotypes and biofilm formation of Pseudomonas aeruginosa PAO1.}, journal = {Natural product research}, volume = {36}, number = {6}, pages = {1663-1667}, doi = {10.1080/14786419.2021.1899174}, pmid = {33719769}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Eugenol/analogs & derivatives ; Phenotype ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {The potential strategy to prevent bacterial pathogenicity is disabling quorum sensing circuits with structural mimicking molecules. Here, we analyzed a synthetic molecule isoeugenol, for inhibition of quorum sensing regulated phenotype and biofilm formation. Isoeugenol was an effective inhibitor, i.e., more than 70% of virulence factors were inhibited including pyocyanin, rhamnolipid, exopolysaccharide, swarming motility and biofilm formation. Interestingly, these quorum sensing regulated phenotypes in Pseudomonas aeruginosa PAO1 were inhibited without affecting the planktonic cells. Moreover, the presence of isoeugenol exhibited more than 70% inhibition of biofilm formation through inhibition of the quorum sensing systems. Furthermore, docking studies suggest that isoeugenol bound to the quorum sensor regulators such as LasI, LasR PqsE and SidA with considerable binding interactions. Our results demonstrate the utility of isoeugenol as a blocker of quorum sensing, which will be functioning as an antivirulence compound.}, } @article {pmid33719058, year = {2021}, author = {Esquivel-Hernández, DA and García-Pérez, JS and Xu, X and Metha, S and Maldonado, J and Xia, S and Zhao, HP and Rittmann, BE and Ontiveros-Valencia, A}, title = {Microbial ecology in selenate-reducing biofilm communities: Rare biosphere and their interactions with abundant phylotypes.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {7}, pages = {2460-2471}, doi = {10.1002/bit.27754}, pmid = {33719058}, issn = {1097-0290}, mesh = {*Bacteria/classification/growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Bioreactors ; Microbial Consortia/*physiology ; *Phylogeny ; Selenic Acid/*metabolism ; }, abstract = {Selenate (SeO4[2-]) reduction in hydrogen (H2)-fed membrane biofilm reactors (H2 -MBfRs) was studied in combinations with other common electron acceptors. We employed H2 -MBfRs with two distinctly different conditions: R1, with ample electron-donor availability and acceptors SeO4[2-] and sulfate (SO4[2-]), and R2, with electron-donor limitation and the presence of electron acceptors SeO4[2-] , nitrate (NO3[-]), and SO4[2-] . Even though H2 was available to reduce all input SeO4[2-] and SO4[2-] in R1, SeO4[2-] reduction was preferred over SO4[2-] reduction. In R2, co-reduction of NO3[-] and SeO4[2-] occurred, and SO4[2-] reduction was mostly suppressed. Biofilms in all MBfRs had high microbial diversity that was influenced by the "rare biosphere" (RB), phylotypes with relative abundance less than 1%. While all MBfR biofilms had abundant members, such as Dechloromonas and Methyloversatilis, the bacterial communities were significantly different between R1 and R2. For R1, abundant genera were Methyloversatilis, Melioribacter, and Propionivibrio; for R2, abundant genera were Dechloromonas, Hydrogenophaga, Cystobacter, Methyloversatilis, and Thauera. Although changes in electron-acceptor or -donor loading altered the phylogenetic structure of the microbial communities, the biofilm communities were resilient in terms of SeO4[2-] and NO3[-] reductions, because interacting members of the RB had the capacity of respiring these electron acceptors.}, } @article {pmid33718885, year = {2021}, author = {Fanelli, F and Caputo, L and Quintieri, L}, title = {Phenotypic and genomic characterization of Pseudomonas putida ITEM 17297 spoiler of fresh vegetables: Focus on biofilm and antibiotic resistance interaction.}, journal = {Current research in food science}, volume = {4}, number = {}, pages = {74-82}, pmid = {33718885}, issn = {2665-9271}, abstract = {Pseudomonas putida is widely recognized as a spoiler of fresh foods under cold storage, and recently associated also with infections in clinical settings. The presence of antibiotic resistance genes (ARGs) could be acquired and transmitted by horizontal genetic transfer and further increase the risk associated with its persistence in food and the need to be deeper investigated. Thus, in this work we presented a genomic and phenotypic analysis of the psychrotrophic P. putida ITEM 17297 to provide new insight into AR mechanisms by this species until now widely studied only for its spoilage traits. ITEM 17297 displayed resistance to several classes of antibiotics and it also formed huge amounts of biofilm; this latter registered increases at 15 °C in comparison to the optimum growth condition (30 °C). After ITEM 17297 biofilms exposure to antibiotic concentrations higher than 10-fold their MIC values no eradication occurred; interestingly, biomasses of biofilm cultivated at 15 °C increased their amount in a dose-dependent manner. Genomic analyses revealed determinants (RND-systems, ABC-transporters, and MFS-efflux pumps) for multi-drugs resistance (β-lactams, macrolides, nalidixic acid, tetracycline, fusidic acid and bacitracin) and a novel ampC allele. Biofilm and motility related pathways were depicted underlying their contribution to AR. Based on these results, underestimated psychrotrophic pseudomonas, such as the herein studied ITEM 17297 strain, might assume relevance in relation to the risk associated with the transfer of antimicrobial resistance genes to humans through cold stored contaminated foods. P. putida biofilm and AR related molecular targets herein identified will provide a basis to clarify the interaction between AR and biofilm formation and to develop novel strategies to counteract the persistence of multidrug resistant P. putida in the food chain.}, } @article {pmid33717030, year = {2021}, author = {Lahiri, D and Nag, M and Sheikh, HI and Sarkar, T and Edinur, HA and Pati, S and Ray, RR}, title = {Microbiologically-Synthesized Nanoparticles and Their Role in Silencing the Biofilm Signaling Cascade.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {636588}, pmid = {33717030}, issn = {1664-302X}, abstract = {The emergence of bacterial resistance to antibiotics has led to the search for alternate antimicrobial treatment strategies. Engineered nanoparticles (NPs) for efficient penetration into a living system have become more common in the world of health and hygiene. The use of microbial enzymes/proteins as a potential reducing agent for synthesizing NPs has increased rapidly in comparison to physical and chemical methods. It is a fast, environmentally safe, and cost-effective approach. Among the biogenic sources, fungi and bacteria are preferred not only for their ability to produce a higher titer of reductase enzyme to convert the ionic forms into their nano forms, but also for their convenience in cultivating and regulating the size and morphology of the synthesized NPs, which can effectively reduce the cost for large-scale manufacturing. Effective penetration through exopolysaccharides of a biofilm matrix enables the NPs to inhibit the bacterial growth. Biofilm is the consortia of sessile groups of microbial cells that are able to adhere to biotic and abiotic surfaces with the help extracellular polymeric substances and glycocalyx. These biofilms cause various chronic diseases and lead to biofouling on medical devices and implants. The NPs penetrate the biofilm and affect the quorum-sensing gene cascades and thereby hamper the cell-to-cell communication mechanism, which inhibits biofilm synthesis. This review focuses on the microbial nano-techniques that were used to produce various metallic and non-metallic nanoparticles and their "signal jamming effects" to inhibit biofilm formation. Detailed analysis and discussion is given to their interactions with various types of signal molecules and the genes responsible for the development of biofilm.}, } @article {pmid33716245, year = {2021}, author = {Hiramine, H and Watanabe, K and Inaba, K and Sasaki, H and Hamada, N}, title = {Evaluation of Antimicrobial Effects on Dental Impression Materials and Biofilm Removal by Sodium Dichloroisocyanurate.}, journal = {Biocontrol science}, volume = {26}, number = {1}, pages = {17-25}, doi = {10.4265/bio.26.17}, pmid = {33716245}, issn = {1884-0205}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Dental Impression Materials ; *Disinfection ; Streptococcus mutans ; Triazines ; }, abstract = {Dental materials are inevitably contaminated with oral microorganisms. To prevent transmission of infectious diseases, impressions need to be disinfected. In the present study, we examined the disinfection effects on impression materials and biofilm removal by sodium dichloroisocyanurate (SDIC). Exponentially growing Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Candida albicans, and dental plaque bacteria were suspended in phosphate buffered saline (PBS) and exposed for 1, 5 and 10 min to 1 mL of the 10 ppm, 100 ppm, 1,000 ppm, and 10,000 ppm SDIC solutions. The bactericidal effect was evaluated by colony forming units of each microorganisms. Moreover, the effect of SDIC solution on S. mutans biofilm was examined. Bactericidal effects of SDIC solutions on oral bacteria on dental impression surfaces were assessed and the surface quality of dental casts after immersion in SDIC solution for 30 min was observed under a scanning electron microscope. The number of all bacterial strains, including plaque bacteria, were significantly decreased by SDIC solution treatment in a dose-dependent manner. Significant S. mutans biofilm removing activity of SDIC was observed in 1,000 and 10,000 ppm solution. The number of oral bacteria adhering to the surfaces of impressions markedly decreased following 10-min immersion in the 1,000 ppm SDIC solution. The 30-min immersion of dental impression in the 1,000 ppm SDIC solution did not adversely affect the surface roughness of dental casts. The results indicate that SDIC Solution is useful to deactivate oral bacteria on dental impression.}, } @article {pmid33715534, year = {2021}, author = {da Silva, BM and Braga, MT and da Silva Passos, JC and Carvalho, ML and Rosseti, IB and de Amorim, LMM and da Rocha, JBT and Alberto-Silva, C and Costa, MS}, title = {(PhSe)2 and (pCl-PhSe)2 organochalcogen compounds inhibit Candida albicans adhesion to human endocervical (HeLa) cells and show anti-biofilm activities.}, journal = {Biofouling}, volume = {37}, number = {2}, pages = {235-245}, doi = {10.1080/08927014.2021.1897110}, pmid = {33715534}, issn = {1029-2454}, mesh = {Antifungal Agents ; *Biofilms ; *Candida albicans ; HeLa Cells ; Humans ; }, abstract = {Adhesion capacity on biological surfaces and biofilm formation is considered an important step in the infection process by Candida albicans. The ability of (PhSe)2 and (pCl-PhSe)2, two synthetic organic selenium (organochalcogen) compounds, to act on C. albicans virulence factors related to adhesion to human endocervical (HeLa) cell surfaces and their anti-biofilm activities was analyzed. Both organochalcogen compounds inhibited C. albicans adhesion to HeLa cells, dependent on compound concentrations. (PhSe)2 (at 20 µM; p = 0.0012) was significantly more effective than (pCl-PhSe)2 (at 20 µM; p = 0.0183) compared with the control. (PhSe)2 inhibited biofilm formation and decreased biofilm viability in both early and mature biofilms more efficiently than (pCl-PhSe)2. Overall, the organochalcogen compounds, especially (PhSe)2, were demonstrated to be effective antifungal drugs against C. albicans virulence factors related to epithelial cell surface adhesion and the formation and viability of biofilms.}, } @article {pmid33715254, year = {2021}, author = {Almohandes, A and Abrahamsson, I and Dahlén, G and Berglundh, T}, title = {Effect of biofilm formation on implant abutments with an anti-bacterial coating: A pre-clinical in vivo study.}, journal = {Clinical oral implants research}, volume = {32}, number = {6}, pages = {756-766}, doi = {10.1111/clr.13745}, pmid = {33715254}, issn = {1600-0501}, support = {//Dentsply Implants IH AB, Mölndal Sweden/ ; }, mesh = {*Alveolar Bone Loss ; Biofilms ; Dental Abutments ; *Dental Implants ; *Dental Plaque ; Humans ; Titanium ; }, abstract = {OBJECTIVES: To analyse the long-term effect of plaque formation on implant abutments with an antibacterial coating and the ensuing host response in peri-implant tissues.

MATERIALS AND METHODS: Four implants were installed in each mandibular premolar region following tooth extraction in six dogs. Three months later, two test abutments with a titanium-bismuth-gallium (Ti-Bi-Ga) coating and two control titanium abutments were connected to the implants on each side of the mandible. After 2 months, ligatures were placed around the implants in one side of the mandible and plaque formation was allowed until the end of the experiment. The ligatures were removed after 4 weeks. Radiographs and microbiological samples were obtained from each implant site during the plaque formation period. Biopsies were obtained 8 months after abutment connection and prepared for histological analysis.

RESULTS: The analysis did not reveal any statistically significant differences in bone loss, bacterial growth and size of inflammatory lesions between implant units with and without the Ti-Bi-Ga coating. Implant sites exposed to the short period of ligature-induced breakdown demonstrated more pronounced bone loss and bacterial growth than non-ligature sites.

CONCLUSIONS: It is suggested that a Ti-Bi-Ga coating does not prevent biofilm formation on the implant device and does not influence the ensuing host response in the adjacent peri-implant mucosa.}, } @article {pmid33714988, year = {2022}, author = {Wilson, SK and Gross, MS}, title = {Biofilm and penile prosthesis infections in the era of coated implants: 2021 update.}, journal = {International journal of impotence research}, volume = {34}, number = {5}, pages = {411-415}, pmid = {33714988}, issn = {1476-5489}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Humans ; Male ; *Penile Diseases/drug therapy ; *Penile Prosthesis/adverse effects ; *Prosthesis-Related Infections/microbiology/prevention & control ; }, abstract = {William Costerton, the pioneer of bacterial biofilm research and Wilson published a review of this subject in 2012. Recent events and false claims have prompted an update for urologists regarding the science of penile implant biofilm. The recent biofilm literature has been investigated and new conclusions regarding penile implant biofilm physiology are clarified in this review. The timeline of biofilm formation is as follows. The wound is contaminated upon incision, and the inoculum of bacteria ceases with incision closure. Almost immediately planktonic bacteria attach to the implant and secrete biofilm which alters the host's ability to eradicate the bacteria. Infection retardant coatings impair clinical infection by common skin organisms including coagulase negative staphylococci, the most frequent offenders. In the modern era of availability of infection retardant coated implants, the increasingly rare penile implant infections are now usually caused by more virulent bugs. Antibiotic elution from the surface of the implant is a tiny dose and only truly helpful in the first 24 h. AMS and Coloplast infection retardant coatings reduce infection equally and contemporary primary implant infections are far lower in experienced implant surgeons' practices.}, } @article {pmid33714640, year = {2021}, author = {Martínez-Meléndez, A and Morfin-Otero, R and Villarreal-Treviño, L and Baines, SD and Camacho-Ortíz, A and Garza-González, E}, title = {Analysis of biofilm production and expression of adhesion structures of circulating Clostridioides difficile strains from Mexico.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.eimc.2021.01.017}, pmid = {33714640}, issn = {2529-993X}, abstract = {INTRODUCTION: Clostridioides difficile biofilms are believed to protect the pathogen from antibiotics, in addition to potentially contributing to recurrent infections.

METHODOLOGY: Biofilm production of 102 C. difficile isolates was determined using the crystal violet staining technique, and detachment assays were performed. The expression levels of cwp84 and slpA genes were evaluated by real-time PCR on selected isolates.

RESULTS: More than 70% of isolates (75/102) were strong biofilm producers, and the highest detachment of biofilm was achieved with the proteinase K treatment (>90%). The overall mean expression of cwp84 was higher in RT027 than in RT001 (p=0.003); among strong biofilm-producing strains, the slpA expression was lower in RT027 than in RT001 (p<0.000).

CONCLUSIONS: Proteins seem to have an important role in the biofilm's initial adherence and maturation. slpA and cwp84 are differentially expressed by C. difficile ribotype and biofilm production level.}, } @article {pmid33714071, year = {2021}, author = {Liu, Y and Li, Y and Shi, L}, title = {Erratum to 'Controlled drug delivery systems in eradicating bacterial biofilm-associated infections' [Journal of Controlled Release, Volume 329 (10 January 2021) 1102-1116].}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {332}, number = {}, pages = {418}, doi = {10.1016/j.jconrel.2021.02.034}, pmid = {33714071}, issn = {1873-4995}, } @article {pmid33713317, year = {2021}, author = {Albayaty, YN and Thomas, N and Ramírez-García, PD and Davis, TP and Quinn, JF and Whittaker, MR and Prestidge, CA}, title = {Polymeric micelles with anti-virulence activity against Candida albicans in a single- and dual-species biofilm.}, journal = {Drug delivery and translational research}, volume = {11}, number = {4}, pages = {1586-1597}, pmid = {33713317}, issn = {2190-3948}, mesh = {Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; *Candida albicans ; Fluconazole/pharmacology ; *Micelles ; Virulence ; }, abstract = {Infections caused by fungal biofilms with rapidly evolving resistance against the available antifungal agents are difficult to manage. These difficulties demand new strategies for effective eradication of biofilms from both biological and inert surfaces. In this study, polymeric micelles comprised of di-block polymer, poly-(ethylene glycol) methyl ether methacrylate and poly 2-(N,N-diethylamino) ethyl methacrylate polymer, P(PEGMA-b-DEAEMA), were observed to exhibit remarkable inhibitory effects on hyphal growth of Candida albicans (C. albicans) and C. tropicalis, thus preventing biofilm formation and removing existing biofilms. P(PEGMA-b-DEAEMA) micelles showed biofilm removal efficacy of > 40% and a 1.4-log reduction in cell viability of C. albicans in its single-species biofilms. In addition, micelles alone promoted high removal percentage in a mixed biofilm of C. albicans and C. tropicalis (~ 70%) and remarkably reduced cell viability of both strains. Co-delivery of fluconazole (Flu) and amphotericin B (AmB) with micelles showed synergistic effects on C. albicans biofilms (3-log reduction for AmB and 2.2-log reduction for Flu). Similar effects were noted on C. albicans planktonic cells when treated with the micellar system combined with AmB but not with Flu. Moreover, micelle-drug combinations showed an enhancement in the antibiofilm activity of Flu and AmB against dual-species biofilms. Furthermore, in vivo studies using Caenorhabditis elegans nematodes revealed no obvious toxicity of the micelles. Targeting morphologic transitions provides a new strategy for defeating fungal biofilms of polymorphic resistance strains and can be potentially used in counteracting Candida virulence.}, } @article {pmid33713222, year = {2021}, author = {Babushkina, IV and Mamonova, IA and Bondarenko, AS and Ulyanov, VY and Norkin, IA}, title = {Cell Immunity in Implant-Associated Infections Caused by Biofilm-Forming Microorganisms.}, journal = {Bulletin of experimental biology and medicine}, volume = {170}, number = {4}, pages = {458-460}, pmid = {33713222}, issn = {1573-8221}, mesh = {B-Lymphocytes/metabolism ; *Biofilms ; Healthy Volunteers ; Humans ; Immunity, Cellular/*physiology ; Staphylococcus/immunology/physiology ; Staphylococcus epidermidis/immunology/physiology ; }, abstract = {High biofilm-forming capacity of Staphylococcus spp. strains isolated from biomaterial of patients with infectious complications after primary knee replacement developed within 6-12 months after surgery was experimentally demonstrated. Differential leukocyte counts and some indicators of cell immunity in these patients were compared with those in patients without purulent complications and healthy volunteers. In patients with implant-associated infection, the relative numbers of T cells (both T-helpers and T-suppressors) B cells were significantly (p<0.05) reduced, while the number of NK cells was significantly increased in comparison with the corresponding parameters in other groups. The revealed changes attest to cell immunity failure in biofilm infection.}, } @article {pmid33711992, year = {2021}, author = {Kok, ESK and Lim, XJ and Chew, SX and Ong, SF and See, LY and Lim, SH and Wong, LA and Davamani, F and Nagendrababu, V and Fawzy, A and Daood, U}, title = {Quaternary ammonium silane (k21) based intracanal medicament triggers biofilm destruction.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {116}, pmid = {33711992}, issn = {1472-6831}, mesh = {*Ammonium Compounds ; Biofilms ; Calcium Hydroxide ; Chlorhexidine/pharmacology ; Dental Pulp Cavity ; Dentin ; Enterococcus faecalis ; Humans ; Root Canal Irrigants/pharmacology ; *Silanes ; }, abstract = {BACKGROUND: Compare antimicrobial efficacy of a quarternary ammonium silane (QAS)/k21 as an intracanal medicament against E. faecalis and C. albicans biofilms formed on root dentin.

METHODOLOGY: Dentin blocks were sterilized and E. faecalis and C. albicans microbial colonies were counted for colony-forming-units against 2%k21, 2%CHX and Ca(OH)2 medicaments. Biofilm colonies after 7 days on dentin were analysed using confocal laser scanning microscopy with live/dead bacterial viability staining. TEM was done to study dentin collagen matrix. Dentin discs from 3rd day and 7th day well plate was used for Raman spectra and observed under fluorescent-microscope. Docking studies were carried out on MMP-2 S[1] binding-domain with k21.

RESULTS: There was reduction of E. faecalis/C. albicans when k21, chlorhexidine and calcium hydroxide were used with highest percentage in 2%k21 treated specimens. 2%k21 showed dense and regular collagen network with intact cross-banding and decreased Raman intensity for 2%k21 on 3rd day. NaOCl + k21 showed least adherence, whereas saline groups showed highest adherence of E. faecalis and C. albicans to root-canal dentin. Alizarin red staining of hDPSCs revealed calcium deposition in all groups with significant difference seen amongst 2%k21 groups. MMP-2 ligand binding was seen accurately indicating possible target sites for k21 intervention.

CONCLUSION: 2%k21 can be considered as alternative intracanal medicament.}, } @article {pmid33711406, year = {2021}, author = {Bijle, MN and Ashraf, U and Abdalla, MM and Yiu, CKY}, title = {The effect of arginine-fluoride varnish on biochemical composition of multi-species biofilm.}, journal = {Journal of dentistry}, volume = {108}, number = {}, pages = {103631}, doi = {10.1016/j.jdent.2021.103631}, pmid = {33711406}, issn = {1879-176X}, mesh = {Arginine ; Biofilms ; Cariostatic Agents/pharmacology ; *Fluorides/pharmacology ; *Fluorides, Topical ; Sodium Fluoride/pharmacology ; }, abstract = {OBJECTIVE: To examine the biochemical components of multi-species biofilm on the arginine (Arg)-sodium fluoride (NaF) varnish-treated enamel following bacterial pH-cycling.

METHODS: l-arginine (at 1%, 2%, & 4% w/v.) was incorporated in a 5% NaF varnish. The experimental and control groups were: 1%, 2%, 4% Arg-NaF, NaF, and no treatment. Enamel blocks were prepared, acid-etched, varnish-treated and then subjected to 72 h bacterial pH-cycling in an oral biofilm reactor. The organic (carbohydrates, proteins, amyloids, and eDNA) and inorganic components (calcium, inorganic phosphate, F) were assayed for the obtained biofilm suspensions. The biofilms were stained for exopolysaccharides (EPS)/bacteria and the respective proportions of live/dead bacteria was determined using confocal imaging.

RESULTS: The total carbohydrate content of the biofilm was the lowest for the 2% and 4% Arg-NaF (p < 0.05). Except for 2% Arg-NaF, the biofilm proteins for 4% Arg-NaF were significantly higher than the other groups (p < 0.05). The amyloids for Arg-NaF groups were significantly lower than the controls (p < 0.05). The eDNA for 4% Arg-NaF was significantly higher than the controls (p < 0.05). The 2% and 4% Arg-NaF-treated enamel had increased biofilm Pi and F compared to the NaF-treated enamel (p < 0.05). The proportion of biofilm EPS matrix to bacteria was significantly reduced in Arg-NaF groups compared to the controls (p < 0.05). The dead bacterial proportions of 4% Arg-NaF were significantly higher than the controls (p < 0.05).

CONCLUSION: Higher concentrations (i.e. 2%/4%) of Arg in 5% NaF varnish have the potential to modulate the biochemical composition of the biofilm growing on the treated enamel.}, } @article {pmid33710353, year = {2021}, author = {Zhang, Y and Hong, W and Chen, Y and Zeng, L and Luo, S}, title = {Proper Skin Management in Breast Augmentation with a Periareolar Incision Prevents Implant Contamination and Biofilm-Related Capsular Contracture.}, journal = {Aesthetic plastic surgery}, volume = {45}, number = {4}, pages = {1451-1457}, pmid = {33710353}, issn = {1432-5241}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; *Contracture ; Humans ; Implant Capsular Contracture/prevention & control/surgery ; *Mammaplasty/adverse effects ; Retrospective Studies ; Staphylococcus aureus ; Treatment Outcome ; }, abstract = {BACKGROUND: Capsular contracture (CC) is a significant complication and major reason for revision in breast augmentation. Many studies indicate that most bacteria found in contracted capsules originate from the skin, especially that of the nipple-areolar complex (NAC). To prevent implant contamination, protocols without a periareolar incision have been proposed and have become a limitation for breast augmentation. We sought to propose a strategy of proper skin management for periareolar incisions to prevent implant contamination and biofilm-related CC.

METHODS: The analyses in this study are based on data collected from February 2017 to July 2020. A total of 129 patients were included, and they were randomized into two groups. The control group was subjected to no skin treatment before the surgery, and the treatment group underwent preoperative cleaning and disinfection of the NAC. We collected bacteriologic swabs used to rub the skin of the NAC and chest after draping and suturing from the control and treatment groups. We assessed the potential risk of detecting bacteria or fungi in the swabs, and we analyzed the data. The relationship between the positive culture rate and complication rate indicated the effectiveness of our strategy.

RESULTS: Initially, 774 swabs were obtained. In the control group, 6 swabs tested positive for pathogens, including 2 NAC swabs positive for Staphylococcus epidermidis (S. epidermidis) after draping and 3 and 1 NAC swabs positive for S. epidermidis and Staphylococcus aureus (S. aureus) after suturing, respectively. All the other samples in the control and treatment groups were negative for bacteria or fungi. All patients had at least 16 months of follow-up. No CC (Baker grades II-IV) was recorded during the follow-up, and the treatment group experienced a better outcome associated with a lower rate of minor complications.

CONCLUSIONS: Proper preoperative skin management helps keep the field pristine and potentially prevents implant contamination and even biofilm-related CC. With this strategy, breast augmentation using a periareolar incision or any other approach, even other surgery, could be a safe procedure.

LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .}, } @article {pmid33708989, year = {2021}, author = {Gerges, BZ and Rosenblatt, J and Truong, YL and Reitzel, RA and Hachem, R and Raad, II}, title = {Enhanced Biofilm Eradication and Reduced Cytotoxicity of a Novel Polygalacturonic and Caprylic Acid Wound Ointment Compared with Common Antiseptic Ointments.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {2710484}, pmid = {33708989}, issn = {2314-6141}, mesh = {Animals ; Anti-Infective Agents, Local/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; *Caprylates/chemistry/pharmacology ; Cell Line ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Mice ; Ointments ; *Pectins/chemistry/pharmacology ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Antiseptic wound ointments are widely used to treat dermal wounds that are microbially contaminated. Polygalacturonic acid (PG)+caprylic acid (CAP) is a novel combination that has been shown to eradicate biofilms. We developed a novel PG+CAP ointment and compared the biofilm eradication capability and cytotoxicity of PG+CAP with that of commercially available antiseptic wound ointments. We used a well-established biofilm model to quantitatively assess the eradication of organisms following exposure to the wound ointments for 2 hours. PG+CAP ointment completely eradicated Candida albicans, multidrug-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus biofilms, whereas MediHoney, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BZK) ointments failed to eradicate all biofilms within 2 hours. We assessed cytotoxicity by exposing L-929 fibroblasts to extracts of each ointment; Trypan blue exclusion was used to assess cell viability, and Alamar blue conversion was used to assess metabolic function. After exposure to PG+CAP and MediHoney, fibroblast viability was 96.23% and 95.23%, respectively (Trypan blue), and was comparable to untreated cells (98.77%). PHMB and BZK showed reduced viability (83.25% and 77.83%, respectively, p < 0.05). Metabolic activity results followed a similar pattern. Cytotoxicity of PG+CAP ointment towards erythrocytes was comparable to saline. PG+CAP ointment seems to be safe and can rapidly eradicate microbial biofilm; thus, PG+CAP ointment merits further in vivo testing as a potential antimicrobial wound ointment.}, } @article {pmid33708324, year = {2020}, author = {Shahbazzadeh, M and Moazamian, E and Rafati, A and Fardin, M}, title = {Antimicrobial resistance pattern, genetic distribution of ESBL genes, biofilm-forming potential, and virulence potential of Pseudomonas aeruginosa isolated from the burn patients in Tehran Hospitals, Iran.}, journal = {The Pan African medical journal}, volume = {36}, number = {}, pages = {233}, pmid = {33708324}, issn = {1937-8688}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Burns/*microbiology ; Drug Resistance, Multiple, Bacterial ; Female ; Hospitals ; Humans ; Iran ; Male ; Polymerase Chain Reaction ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/*genetics/isolation & purification ; Virulence ; Wound Infection/microbiology ; beta-Lactamases/genetics ; }, abstract = {INTRODUCTION: according to the studies performed, researchers considered Pseudomonas aeruginosa (P. aeruginosa) as the major cause of infectious diseases like burn and wound infection that makes it one of the most threatening opportunistic pathogens. The present research aimed at investigating antimicrobial resistance, biofilm-forming abilities, and frequency of the genes contributed to blaVEB-1, blaPER-1, and blaPSE-1 genes and virulence of P. aeruginosa separated from the burn infections in Tehran, Iran.

METHODS: we evaluated the resistance of 156 P. aeruginosa isolates to fifteen antimicrobial agents and generation of the ESBL and MBL enzymes phenotypically based on the CLSI instructions. Moreover, the biofilm forming potential has been assayed in a microtitre plate. In addition, PCR has been used to examine the frequency of virulence-and biofilm-related genes. Furthermore, the PCR of blaVEB-1, blaPSE-1, and blaPER-1 genes has been amplified.

RESULTS: according to the results, 72.2% of P. aeruginosa isolates have been MDR and 35.6% and 55.5% have been positive for producing MBL and ESBL, respectively. Moreover, 67.8% have been positive for forming biofilms. It has been found that 15.3% isolates are ESBL-positive; from among them 60% belong to the females and 40% belong to the males. In addition, one and two isolates respectively harbored the blaVEB-1and blaPER-1genes.

CONCLUSION: the present research outputs indicated the higher frequency of the multi drug resistance and higher percent of the virulence-related genes in the clinical P. aeruginosa isolates in Iran.}, } @article {pmid33708216, year = {2021}, author = {de Morais, SD and Kak, G and Menousek, JP and Kielian, T}, title = {Immunopathogenesis of Craniotomy Infection and Niche-Specific Immune Responses to Biofilm.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {625467}, pmid = {33708216}, issn = {1664-3224}, support = {R01 NS107369/NS/NINDS NIH HHS/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biofilms/growth & development ; Central Nervous System Bacterial Infections/immunology/metabolism/*microbiology/therapy ; Craniotomy/*adverse effects ; Host-Pathogen Interactions ; Humans ; *Immunity, Innate ; Myeloid Differentiation Factor 88/metabolism ; Staphylococcal Infections/immunology/metabolism/*microbiology/therapy ; Staphylococcus aureus/growth & development/*immunology ; Surgical Wound Infection/immunology/metabolism/*microbiology/therapy ; Toll-Like Receptor 2/metabolism ; }, abstract = {Bacterial infections in the central nervous system (CNS) can be life threatening and often impair neurological function. Biofilm infection is a complication following craniotomy, a neurosurgical procedure that involves the removal and replacement of a skull fragment (bone flap) to access the brain for surgical intervention. The incidence of infection following craniotomy ranges from 1% to 3% with approximately half caused by Staphylococcus aureus (S. aureus). These infections present a significant therapeutic challenge due to the antibiotic tolerance of biofilm and unique immune properties of the CNS. Previous studies have revealed a critical role for innate immune responses during S. aureus craniotomy infection. Experiments using knockout mouse models have highlighted the importance of the pattern recognition receptor Toll-like receptor 2 (TLR2) and its adaptor protein MyD88 for preventing S. aureus outgrowth during craniotomy biofilm infection. However, neither molecule affected bacterial burden in a mouse model of S. aureus brain abscess highlighting the distinctions between immune regulation of biofilm vs. planktonic infection in the CNS. Furthermore, the immune responses elicited during S. aureus craniotomy infection are distinct from biofilm infection in the periphery, emphasizing the critical role for niche-specific factors in dictating S. aureus biofilm-leukocyte crosstalk. In this review, we discuss the current knowledge concerning innate immunity to S. aureus craniotomy biofilm infection, compare this to S. aureus biofilm infection in the periphery, and discuss the importance of anatomical location in dictating how biofilm influences inflammatory responses and its impact on bacterial clearance.}, } @article {pmid33707690, year = {2021}, author = {Tan, J and Kerstetter, JE and Turcotte, MM}, title = {Eco-evolutionary interaction between microbiome presence and rapid biofilm evolution determines plant host fitness.}, journal = {Nature ecology & evolution}, volume = {5}, number = {5}, pages = {670-676}, pmid = {33707690}, issn = {2397-334X}, mesh = {Biofilms ; *Microbiota ; Plants ; }, abstract = {Microbiomes are important to the survival and reproduction of their hosts. Although ecological and evolutionary processes can happen simultaneously in microbiomes, little is known about how microbiome eco-evolutionary dynamics determine host fitness. Here we show, using experimental evolution, that fitness of the aquatic plant Lemna minor is modified by interactions between the microbiome and the evolution of one member, Pseudomonas fluorescens. Microbiome presence promotes P. fluorescens' rapid evolution to form biofilm, which reciprocally alters the microbiome's species composition. These eco-evolutionary dynamics modify the host's multigenerational fitness. The microbiome and non-evolving P. fluorescens together promote host fitness, whereas the microbiome with P. fluorescens that evolves biofilm reduces the beneficial impact on host fitness. Additional experiments suggest that the microbial effect on host fitness may occur through changes in microbiome production of auxin, a plant growth hormone. Our study, therefore, experimentally demonstrates the importance of the eco-evolutionary dynamics in microbiomes for host-microbiome interactions.}, } @article {pmid33707544, year = {2021}, author = {Awadh, AA and Le Gresley, A and Forster-Wilkins, G and Kelly, AF and Fielder, MD}, title = {Determination of metabolic activity in planktonic and biofilm cells of Mycoplasma fermentans and Mycoplasma pneumoniae by nuclear magnetic resonance.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {5650}, pmid = {33707544}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Diffusion ; *Magnetic Resonance Spectroscopy ; Mycoplasma fermentans/cytology/growth & development/*metabolism ; Mycoplasma pneumoniae/cytology/growth & development/*metabolism ; Plankton/*metabolism ; Principal Component Analysis ; Serum ; }, abstract = {Mycoplasmas are fastidious microorganisms, typically characterised by their restricted metabolism and minimalist genome. Although there is reported evidence that some mycoplasmas can develop biofilms little is known about any differences in metabolism in these organisms between the growth states. A systematic metabolomics approach may help clarify differences associated between planktonic and biofilm associated mycoplasmas. In the current study, the metabolomics of two different mycoplasmas of clinical importance (Mycoplasma pneumoniae and Mycoplasma fermentans) were examined using a novel approach involving nuclear magnetic resonance spectroscopy and principle component analysis. Characterisation of metabolic changes was facilitated through the generation of high-density metabolite data and diffusion-ordered spectroscopy that provided the size and structural information of the molecules under examination. This enabled the discrimination between biofilms and planktonic states for the metabolomic profiles of both organisms. This work identified clear biofilm/planktonic differences in metabolite composition for both clinical mycoplasmas and the outcomes serve to establish a baseline understanding of the changes in metabolism observed in these pathogens in their different growth states. This may offer insight into how these organisms are capable of exploiting and persisting in different niches and so facilitate their survival in the clinical setting.}, } @article {pmid33707445, year = {2021}, author = {Chakraborty, P and Bajeli, S and Kaushal, D and Radotra, BD and Kumar, A}, title = {Biofilm formation in the lung contributes to virulence and drug tolerance of Mycobacterium tuberculosis.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {1606}, pmid = {33707445}, issn = {2041-1723}, support = {P51 OD011133/OD/NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cellulase/pharmacology ; Cellulose/*metabolism ; Disease Models, Animal ; Drug Resistance, Multiple, Bacterial/*physiology ; Drug Synergism ; Humans ; Isoniazid/pharmacology ; Mice ; Mice, Inbred C57BL ; Mycobacterium abscessus/growth & development ; Mycobacterium avium/growth & development ; Mycobacterium fortuitum/growth & development ; Mycobacterium tuberculosis/drug effects/*growth & development/*metabolism ; Rifampin/pharmacology ; Tuberculosis, Pulmonary/drug therapy/pathology ; }, abstract = {Tuberculosis is a chronic disease that displays several features commonly associated with biofilm-associated infections: immune system evasion, antibiotic treatment failures, and recurrence of infection. However, although Mycobacterium tuberculosis (Mtb) can form cellulose-containing biofilms in vitro, it remains unclear whether biofilms are formed during infection in vivo. Here, we demonstrate the formation of Mtb biofilms in animal models of infection and in patients, and that biofilm formation can contribute to drug tolerance. First, we show that cellulose is also a structural component of the extracellular matrix of in vitro biofilms of fast and slow-growing nontuberculous mycobacteria. Then, we use cellulose as a biomarker to detect Mtb biofilms in the lungs of experimentally infected mice and non-human primates, as well as in lung tissue sections obtained from patients with tuberculosis. Mtb strains defective in biofilm formation are attenuated for survival in mice, suggesting that biofilms protect bacilli from the host immune system. Furthermore, the administration of nebulized cellulase enhances the antimycobacterial activity of isoniazid and rifampicin in infected mice, supporting a role for biofilms in phenotypic drug tolerance. Our findings thus indicate that Mtb biofilms are relevant to human tuberculosis.}, } @article {pmid33707371, year = {2021}, author = {Polyudova, TV and Eroshenko, DV and Pimenova, EV}, title = {The biofilm formation of nontuberculous mycobacteria and its inhibition by essential oils.}, journal = {International journal of mycobacteriology}, volume = {10}, number = {1}, pages = {43-50}, doi = {10.4103/ijmy.ijmy_228_20}, pmid = {33707371}, issn = {2212-554X}, mesh = {Biofilms ; Mycobacterium avium ; Mycobacterium smegmatis ; *Nontuberculous Mycobacteria ; *Oils, Volatile/pharmacology ; }, abstract = {BACKGROUND: Nontuberculous mycobacteria (NTM) form two types of biofilms: Bottom biofilm and pellicle. The spatial distribution of cells between these types of biofilms and their dispersion into the liquid medium depends on the ratio of the nutrient components of the growth medium. The inhibition of biofilm formation by NTM can be achieved through the use of lipophilic compounds, such as essential oils (EOs).

METHOD: The biofilm and pellicle formation of Mycobacterium smegmatis and Mycobacterium avium on four nutrient media under static conditions and in the vapors of six EOs was evaluated by conventional method. The antimycobacterial effect of EOs was also studied by the disc diffusion method.

RESULTS: The bottom biofilm and pellicle formation of NTM largely depended on the composition and availability of nutrients. Nutrient media in which NTM form powerful bottom biofilm or pellicle or both have been determined. The growth of studied NTM strains on agar was highly sensitive to the EOs of Scots pine, Atlas cedar, bergamot, and a mixture of EO of different plants. The cultivation of bacteria in the EO vapors also resulted in total suppression of the pellicle for all studied NTM strains.

CONCLUSIONS: Our data clearly indicate that the carbon-nitrogen ratio is involved in the regulation of the spatial distribution of the biofilm. The preventing effect of EOs vapors, especially the synergistic action of mixture of EOs on the biofilm and pellicle formation by NTMs can be observed.}, } @article {pmid33707049, year = {2021}, author = {Oliveira, F and Rohde, H and Vilanova, M and Cerca, N}, title = {The Emerging Role of Iron Acquisition in Biofilm-Associated Infections.}, journal = {Trends in microbiology}, volume = {29}, number = {9}, pages = {772-775}, doi = {10.1016/j.tim.2021.02.009}, pmid = {33707049}, issn = {1878-4380}, mesh = {Animals ; Bacteria/genetics/*metabolism/pathogenicity ; Bacterial Infections/*microbiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Humans ; Iron/*metabolism ; Siderophores/metabolism ; Virulence ; }, abstract = {A possible association between iron and biofilm formation has been explored for a long time. Here, we focus on major recent advances that shed light on the mechanisms behind this relationship and discuss how siderophore-mediated iron acquisition may impact the virulence of important nosocomial pathogens.}, } @article {pmid33704753, year = {2021}, author = {Holden, NJ and Wright, KM and Marshall, J and Holmes, A}, title = {Functional Analysis of Shiga Toxin-Producing Escherichia coli Biofilm Components in Plant Leaves.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2291}, number = {}, pages = {163-175}, pmid = {33704753}, issn = {1940-6029}, mesh = {Biofilms/*growth & development ; Fruit/microbiology ; Humans ; Plant Leaves/*microbiology ; *Shiga-Toxigenic Escherichia coli/classification/isolation & purification/physiology ; }, abstract = {Plants represent alternative or secondary hosts for Shiga toxin-producing Escherichia coli (STEC), enabling transmission of the pathogens through the food chain on horticultural crops. This becomes a public health concern for plants that are eaten raw or minimally processed, such as leafy salad and fruits. STEC actively interact with plants as hosts, and so to determine the mechanistic basis to the interaction, it is necessary to assess STEC gene function in planta. Here, we describe analysis of an STEC biofilm component, curli, that plays a role in STEC colony formation in plant leaves. It also serves as a suitable example of the approaches required for qualitative and quantitative assessment of functional host colonization traits.}, } @article {pmid33703923, year = {2021}, author = {Scheik, LK and Volcan Maia, DS and Würfel, SFR and Ramires, T and Kleinubing, NR and Haubert, L and Lopes, GV and da Silva, WP}, title = {Biofilm-forming ability of poultry Campylobacter jejuni strains in the presence and absence of Pseudomonas aeruginosa.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {4}, pages = {301-309}, doi = {10.1139/cjm-2020-0256}, pmid = {33703923}, issn = {1480-3275}, mesh = {Abattoirs ; Animals ; Biofilms/*growth & development ; Campylobacter jejuni/isolation & purification/*physiology ; Microbial Interactions ; Oxygen/analysis ; Poultry/*microbiology ; Pseudomonas aeruginosa/*physiology ; Surface Properties ; Temperature ; }, abstract = {The aims of this study were to evaluate the ability of Campylobacter jejuni isolated from a poultry slaughterhouse to form biofilm in the presence and absence of Pseudomonas aeruginosa, and the effect of surface (stainless steel, polystyrene), temperature (7, 25, and 42 °C), and oxygen concentration (microaerophilic and aerobic conditions) on the formation of biofilm. The genes ahpC, cadF, clpP, dnaJ, docA, flaA, flaB, katA, kpsM, luxS, racR, and sodB, related to biofilm formation by C. jejuni, were also investigated. All isolates formed biofilm on stainless steel and on polystyrene, in both aerobic and microaerophilic atmospheres, including temperatures not optimal for C. jejuni growth (7 and 25 °C), and biofilm also was formed in the presence of P. aeruginosa. In dual-species biofilm on stainless steel, biofilm formation was 2-6 log CFU·cm[-2] higher at 7 °C for all isolates, in comparison with monospecies biofilm. Ten genes (ahpC, cadF, clpP, dnaJ, docA, flaA, flaB, luxS, racR, and sodB) were detected in all isolates, but katA and kpsM were found in four and six isolates, respectively. The results obtained are of concern because the poultry C. jejuni isolates form biofilm in different conditions, which is enhanced in the presence of other biofilm formers, such as P. aeruginosa.}, } @article {pmid33694241, year = {2021}, author = {Aguiar, PADF and Menezes, RP and Penatti, MPA and Moreira, TA and Pimenta, JP and Silva, NBS and Röder, DVDB}, title = {Rapid detection of biofilm-producing Candida species via MALDI-TOF mass spectrometry.}, journal = {Journal of applied microbiology}, volume = {131}, number = {4}, pages = {2049-2060}, doi = {10.1111/jam.15066}, pmid = {33694241}, issn = {1365-2672}, mesh = {Biofilms ; *Candida ; Candida albicans ; *Candidemia ; Humans ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {AIMS: The aim of this study was to evaluate the formation of biofilm by Candida spp. isolated from the bloodstream, using traditional spectrophotometric methodologies. In addition, the goal was to compare the results with those obtained through MALDI-TOF/MS, as well as to verify its use as a potential tool for the detection of biofilm-forming strains.

METHODS AND RESULTS: Hundred and thirteen isolates of Candida spp. were studied: 41 were Candida albicans, 27 C. tropicalis, 18 C. glabrata, 17 C. parapsilosis and 10 C. krusei. Metabolic activity was determined through the tetrazolium salt (XTT) reduction assay and biomass by staining with Crystal Violet. All isolates were able to form biofilm, 94% of which were strong producers, with high biomass quantification (95%; 107/113) and high metabolic activity (99%; 112/113). Mass spectra of the biofilm-producing isolates showed differences in the intensity of mass peaks when compared with the spectra of the nonproducing strains.

CONCLUSIONS: It was demonstrated that MALDI-TOF/MS was able to detect specific biofilm proteins, as the mass spectra of the isolates presented differences when compared with nonproducing strains.

MALDI-TOF/MS can become a valuable tool for biofilm detection at the moment of the identification of the microorganism, thus contributing greatly to the management of patients with Candidemia.}, } @article {pmid33692800, year = {2021}, author = {Moser, C and Jensen, PØ and Thomsen, K and Kolpen, M and Rybtke, M and Lauland, AS and Trøstrup, H and Tolker-Nielsen, T}, title = {Immune Responses to Pseudomonas aeruginosa Biofilm Infections.}, journal = {Frontiers in immunology}, volume = {12}, number = {}, pages = {625597}, pmid = {33692800}, issn = {1664-3224}, mesh = {*Adaptive Immunity/drug effects ; Animals ; Anti-Bacterial Agents/therapeutic use ; *Biofilms/drug effects/growth & development ; Host-Pathogen Interactions ; Humans ; *Immunity, Innate/drug effects ; Immunization, Passive ; Immunologic Factors/therapeutic use ; Pseudomonas Infections/*immunology/microbiology/therapy ; Pseudomonas aeruginosa/drug effects/growth & development/*immunology ; }, abstract = {Pseudomonas aeruginosa is a key pathogen of chronic infections in the lungs of cystic fibrosis patients and in patients suffering from chronic wounds of diverse etiology. In these infections the bacteria congregate in biofilms and cannot be eradicated by standard antibiotic treatment or host immune responses. The persistent biofilms induce a hyper inflammatory state that results in collateral damage of the adjacent host tissue. The host fails to eradicate the biofilm infection, resulting in hindered remodeling and healing. In the present review we describe our current understanding of innate and adaptive immune responses elicited by P. aeruginosa biofilms in cystic fibrosis lung infections and chronic wounds. This includes the mechanisms that are involved in the activation of the immune responses, as well as the effector functions, the antimicrobial components and the associated tissue destruction. The mechanisms by which the biofilms evade immune responses, and potential treatment targets of the immune response are also discussed.}, } @article {pmid33691179, year = {2021}, author = {Oliveira, VC and Steixner, S and Nascimento, CD and Pagnano, VO and Silva-Lovato, CH and Paranhos, HFO and Wilflingseder, D and Coraça-Huber, D and Watanabe, E}, title = {Expression of virulence factors by Pseudomonas aeruginosa biofilm after bacteriophage infection.}, journal = {Microbial pathogenesis}, volume = {154}, number = {}, pages = {104834}, doi = {10.1016/j.micpath.2021.104834}, pmid = {33691179}, issn = {1096-1208}, mesh = {*Bacteriophages ; Biofilms ; Humans ; *Pseudomonas Infections ; Pseudomonas aeruginosa/genetics ; Quorum Sensing ; Virulence ; Virulence Factors/genetics ; }, abstract = {The use of bacteriophages for the treatment of bacterial infections has been extensively studied. Nonetheless, the stress response regarding bacteriophage infection and the expression of virulence factors of Pseudomonas aeruginosa after phage infection is poorly discussed. In this study, we evaluated biofilm formation capacity and expression of virulence factors of P. aeruginosa after bacteriophage infection. Biofilm growth rates, biofilm morphology, pyocyanin production and elastase activity were evaluated after 2, 8, 24 and 48 h of co-cultivation with bacteriophages that was recently characterized and showed to be infective towards clinical isolates. In parallel, quantitative real-time polymerase chain reactions were carried out to verify the expression of virulence-related genes. Bacteriophages promoted substantial changes in P. aeruginosa biofilm growth at early co-culture time. In addition, at 8 h, we observed that some cultures developed filaments. Although bacteriophages did not alter both pyocyanin and protease activity, changes on the expression level of genes related to virulence factors were detected. Usually, lasI, pslA, lasB and phzH genes were upregulated after 2 and 48 h of co-culture. These results highlight the need for extensive investigation of pathways and molecules involved in phage infection, since the transcriptional changes would suggest a response activation by P. aeruginosa.}, } @article {pmid33691176, year = {2021}, author = {Guo, H and Chen, Y and Guo, W and Chen, J}, title = {Effects of extracellular DNA on dual-species biofilm formed by Streptococcus mutans and Candida albicans.}, journal = {Microbial pathogenesis}, volume = {154}, number = {}, pages = {104838}, doi = {10.1016/j.micpath.2021.104838}, pmid = {33691176}, issn = {1096-1208}, mesh = {Biofilms ; Candida albicans/genetics ; DNA ; *Dental Caries ; Humans ; *Streptococcus mutans/genetics ; }, abstract = {Streptococcus mutans is the most important acid-producing pathogen that causes dental caries, while Candida albicans is an opportunistic fungal pathogen that is frequently detected in conjunction with heavy infection by S. mutans. Their interactions in dental plaque biofilms remain unclear. Extracellular DNA (eDNA) is found in oral biofilms, but its effects have not been thoroughly defined. In this study, the role of eDNA in dual-species biofilms formed by S. mutans and C. albicans was investigated. With eDNA removal, the growth of both strains was not affected, but the formation of dual-species biofilms obviously decreased. In addition, the removal of eDNA spatially disrupted the structure of the dual-species biofilm. It was also shown that eDNA mainly affected the initial attachment and development stages of the dual-species biofilms but not the well-developed biofilms. A similar phenomenon was also observed in the cell viability of dual-species biofilms after DNase I treatment. To further exploration, we analyzed the expression of genes associated with biofilm formation in both S. mutans and C. albicans. We determined that the co-cultivation of S. mutans and C. albicans promotes the expression of genes related to extracellular polysaccharide production (e.g., gtfC), adhesion (e.g., spaP, epa1), mycelial transformation (e.g., hwp1), and drug resistance (e.g., cdr2). However, these genes were significantly downregulated when the eDNA of the dual-species biofilm was removed by adding DNase I compared to those untreated groups. Altogether, eDNA removal, such as that by DNase I treatment, could be considered a promising strategy to control oral biofilms and biofilm-associated oral diseases.}, } @article {pmid33690911, year = {2021}, author = {Jakubovics, NS and Goodman, SD and Mashburn-Warren, L and Stafford, GP and Cieplik, F}, title = {The dental plaque biofilm matrix.}, journal = {Periodontology 2000}, volume = {86}, number = {1}, pages = {32-56}, pmid = {33690911}, issn = {1600-0757}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; RPGF1810/101/DMT_/The Dunhill Medical Trust/United Kingdom ; }, mesh = {Biofilms ; *Dental Caries ; *Dental Plaque ; Extracellular Polymeric Substance Matrix ; Humans ; *Periodontitis ; }, abstract = {The extracellular matrix is a critical component of microbial biofilms, such as dental plaque, maintaining the spatial arrangement of cells and coordinating cellular functions throughout the structure. The extracellular polymeric substances that comprise the matrix include carbohydrates, nucleic acids, proteins, and lipids, which are frequently organized into macromolecular complexes and/or are associated with the surfaces of microbial cells within the biofilm. Cariogenic dental plaque is rich in glucan and fructan polysaccharides derived from extracellular microbial metabolism of dietary sucrose. By contrast, the matrix of subgingival dental plaque is a complex mixture of macromolecules that is still not well understood. Components of the matrix escape from microbial cells during lysis by active secretion or through the shedding of vesicles and serve to anchor microbial cells to the tooth surface. By maintaining the biofilm in close association with host tissues, the matrix facilitates interactions between microorganisms and the host. The outcome of these interactions may be the maintenance of health or the development of dental disease, such as caries or periodontitis. The matrix affords microbial cells protection against chemical and physical insults and hinders the eradication of pathogenic dental plaque. Therefore, strategies to control the matrix are critical to maintain oral health. This review discusses recent advances in our understanding of the composition, origins, and function of the dental plaque matrix, with a focus on subgingival dental plaque. New strategies to control subgingival dental plaque based on targeting the biofilm matrix are also considered.}, } @article {pmid33689487, year = {2021}, author = {Sato, T and Uno, T and Kawamura, M and Fujimura, S}, title = {In vitro Tolerability of Biofilm-Forming Trimethoprim-/Sulfamethoxazole-Resistant Small Colony Variants of Staphylococcus aureus Against Various Antimicrobial Agents.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {9}, pages = {1282-1289}, doi = {10.1089/mdr.2020.0379}, pmid = {33689487}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/*drug effects/genetics ; Genes, Bacterial ; Microbial Sensitivity Tests ; RNA, Messenger/biosynthesis ; Staphylococcus aureus/*drug effects/genetics ; Trimethoprim, Sulfamethoxazole Drug Combination/*pharmacology ; }, abstract = {Trimethoprim-/sulfamethoxazole-resistant small colony variants (SCVs) of Staphylococcus aureus, which are selected by use of trimethoprim/sulfamethoxazole, are involved in intractable biofilm-forming infection. This study aimed to determine the biofilm formation ability in trimethoprim-/sulfamethoxazole-resistant SCVs of S. aureus and investigate the bactericidal activity of differential antimicrobial agents to its biofilm-forming S. aureus. Between 32 S. aureus wild type (WT) and 32 SCVs selected from its WT, the amount of formed biofilm was compared. Vancomycin, daptomycin, rifampicin, and minocycline were exposed to biofilm-forming S. aureus to determine viable bacterial counts and its susceptibility. The biofilm-producing quantify of SCVs was approximately twice that formed by its WT. Vancomycin and daptomycin reduce 4 logs the bacterial counts of biofilm-forming WT at 24 hours, but did not affect SCVs. Rifampicin and minocycline considerably decreased both WT and SCVs; however, both bacterial counts recovered to an initial number 48 hours later. These survival strains showed resistance to each drug, and rpoB mutation or tet38 mRNA overexpression was confirmed.}, } @article {pmid33689469, year = {2021}, author = {Liu, Y and Wu, H and Sun, Z and Xu, X and Liu, F}, title = {Contamination and Biofilm Formation of Foodborne and Opportunistic Pathogens in Yellow-Feathered Chicken Carcass.}, journal = {Foodborne pathogens and disease}, volume = {18}, number = {3}, pages = {210-218}, doi = {10.1089/fpd.2020.2876}, pmid = {33689469}, issn = {1556-7125}, mesh = {Animals ; Biofilms/*growth & development ; Chickens/*microbiology ; *Food Microbiology ; Polysaccharides, Bacterial/*biosynthesis ; Seasons ; }, abstract = {This study aims to analyze the contamination and biofilm formation of foodborne and opportunistic pathogens in yellow-feathered chicken carcasses sampled in different seasons and to prove the relationship between biofilm-forming ability and bacterial extracellular polysaccharide (EPS) production. A total of 78 strains were isolated from chicken samples. The strains consisted of 30.8% Escherichia coli, 14.1% Pseudomonas aeruginosa, 12.8% Salmonella enteritidis, 12.8% Klebsiella pnenmoniae, 10.2% Enterobacter cloacae, 8.9% Proteus mirabilis, 5.1% Klebsiella oxytoca, 1.3% Staphylococcus aureus, and 1.3% Citrobacter braakii. Crystal violet staining assay revealed six strains with strong biofilm-forming ability, namely, E. coli S7, K. oxytoca B12, K. pnenmoniae B6, S. enteritidis H4, P. aeruginosa M5, and S. aureus G1, which showed had high abilities of cell motility and EPS production. Confocal laser scanning microscopy and scanning electron microscopy showed that all six strains can form mature biofilm architectures after 5 d of cultivation. This study may serve as a reference to control the contamination of foodborne pathogens in yellow-feathered chicken and enhance the quality and shelf life of these chicken products.}, } @article {pmid33688992, year = {2021}, author = {Barghouthy, Y and Wiseman, O and Ventimiglia, E and Letendre, J and Cloutier, J and Daudon, M and Kleinclauss, F and Doizi, S and Corrales, M and Traxer, O}, title = {Silicone-hydrocoated ureteral stents encrustation and biofilm formation after 3-week dwell time: results of a prospective randomized multicenter clinical study.}, journal = {World journal of urology}, volume = {39}, number = {9}, pages = {3623-3629}, pmid = {33688992}, issn = {1433-8726}, mesh = {Adult ; *Biofilms ; *Coated Materials, Biocompatible ; Female ; Humans ; Male ; Middle Aged ; *Polymers ; Postoperative Complications/*etiology ; Prospective Studies ; Prosthesis Design ; *Silicones ; Single-Blind Method ; Stents/*adverse effects ; Time Factors ; Ureter/*surgery ; }, abstract = {OBJECTIVE: To explore the risk of encrustation and biofilm formation for silicone ureteral stents compared to percuflex polymer stents, through a randomized multicenter study.

PATIENTS AND METHODS: Design, setting and participants: A Multicenter, prospective, randomized, single blind, comparative study of hydrocoated silicone stent (Coloplast Imajin[®] hydro) versus Percuflex™ Plus stent (Boston Scientific), in 141 patients treated by flexible URS for a kidney stone. The study had ethical committee approval in the respective hospitals. Outcome measurements and statistical analysis: Endpoints related to encrustation were biofilm formation and mineral encrustation after a period of 3-week indwelling time. They were evaluated at removal through a scoring scale of ureteral stents encrustation, infrared spectroscopy and optical microscopy of inner and outer surfaces of tips, angles and along the stent's body. Comparison was performed using ANOVA.

RESULTS: 119 stents were available after removal for analysis, 56 in the silicone and 63 in the Percuflex TM Plus group. Mean dwelling duration was 21.8 days for silicone, 22.1 days for PercuflexTM Plus. There was significantly more biofilm on Percuflex™ Plus compared to silicone (1.24 ± 0.08 vs 0.93 ± 0.09, p = 0.0021), and more mineral encrustation (1.22 ± 0.10 vs 0.78 ± 0.11, p = 0.0048), respectively.

CONCLUSIONS: This multicenter randomized study shows that silicone-hydrocoated stents are less prone to encrustation than PercuflexTM Plus after a 3-week dwelling period and confirms the low encrustation potential of silicone.}, } @article {pmid33688348, year = {2021}, author = {Gunardi, WD and Karuniawati, A and Umbas, R and Bardosono, S and Lydia, A and Soebandrio, A and Safari, D}, title = {Biofilm-Producing Bacteria and Risk Factors (Gender and Duration of Catheterization) Characterized as Catheter-Associated Biofilm Formation.}, journal = {International journal of microbiology}, volume = {2021}, number = {}, pages = {8869275}, pmid = {33688348}, issn = {1687-918X}, abstract = {BACKGROUND: A catheter-associated urinary tract infection (CA-UTI) is preceded by biofilm formation, which is related to several risk factors such as gender, age, diabetic status, duration of catheterization, bacteriuria before catheterization, virulence gene factor, and antibiotic usage.

AIMS: This study aims to identify the microbial composition of catheter samples, including its corresponding comparison with urine samples, to determine the most important risk factors of biofilm formation and characterize the virulence gene factors that correlate with biofilm formation.

METHODS: A longitudinal cross-sectional study was conducted on 109 catheterized patients from September 2017 to January 2018. The risk factors were obtained from the patients' medical records. All catheter and urine samples were cultured after removal, followed by biomass quantification. Isolate identification and antimicrobial susceptibility testing were performed using the Vitex2 system. Biofilm-producing bacteria were identified by the Congo Red Agar (CRA) method. A PCR test characterized the virulence genes of dominant bacteria (E. coli). All data were collected and processed for statistical analysis.

RESULTS: Out of 109 catheterized patients, 78% of the catheters were culture positive, which was higher than those of the urine samples (37.62%). The most common species isolated from the catheter cultures were Escherichia coli (28.1%), Candida sp. (17.8%), Klebsiella pneumoniae (15.9%), and Enterococcus faecalis (13.1%). E. coli (83.3%) and E. faecalis (78.6%) were the main isolates with a positive CRA. A statistical analysis showed that gender and duration prior to catheterization were associated with an increased risk of biofilm formation (p < 0.05).

CONCLUSION: E. coli and E. faecalis were the most common biofilm-producing bacteria isolated from the urinary catheter. Gender and duration are two risk factors associated with biofilm formation, therefore determining the risk of CAUTI. The presence of PapC as a virulence gene encoding pili correlates with the biofilm formation. Biofilm-producing bacteria, female gender, duration of catheterization (more than five days), and PapC gene presence have strong correlation with the biofilm formation. To prevent CAUTI, patients with risk factors should be monitored by urinalysis tests to detect earlier the risk of biofilm formation.}, } @article {pmid33685971, year = {2021}, author = {Thongbhubate, K and Nakafuji, Y and Matsuoka, R and Kakegawa, S and Suzuki, H}, title = {Effect of Spermidine on Biofilm Formation in Escherichia coli K-12.}, journal = {Journal of bacteriology}, volume = {203}, number = {10}, pages = {}, pmid = {33685971}, issn = {1098-5530}, mesh = {ATP-Binding Cassette Transporters/genetics/metabolism ; Acetyltransferases/metabolism ; Amide Synthases/metabolism ; Biofilms/*growth & development ; Cadaverine/pharmacology ; Culture Media ; Escherichia coli K12/drug effects/genetics/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Gene Deletion ; Membrane Transport Proteins/genetics/*metabolism ; Mutation ; Operon ; Periplasmic Binding Proteins/genetics/*metabolism ; Putrescine/pharmacology ; Spermidine/*metabolism/pharmacology ; Spermidine Synthase/genetics/metabolism ; }, abstract = {Polyamines are essential for biofilm formation in Escherichia coli, but it is still unclear which polyamines are primarily responsible for this phenomenon. To address this issue, we constructed a series of E. coli K-12 strains with mutations in genes required for the synthesis and metabolism of polyamines. Disruption of the spermidine synthase gene (speE) caused a severe defect in biofilm formation. This defect was rescued by the addition of spermidine to the medium but not by putrescine or cadaverine. A multidrug/spermidine efflux pump membrane subunit (MdtJ)-deficient strain was anticipated to accumulate more spermidine and result in enhanced biofilm formation compared to the MdtJ[+] strain. However, the mdtJ mutation did not affect intracellular spermidine or biofilm concentrations. E. coli has the spermidine acetyltransferase (SpeG) and glutathionylspermidine synthetase/amidase (Gss) to metabolize intracellular spermidine. Under biofilm-forming conditions, not Gss but SpeG plays a major role in decreasing the too-high intracellular spermidine concentrations. Additionally, PotFGHI can function as a compensatory importer of spermidine when PotABCD is absent under biofilm-forming conditions. Last, we report here that, in addition to intracellular spermidine, the periplasmic binding protein (PotD) of the spermidine preferential ABC transporter is essential for stimulating biofilm formation.IMPORTANCE Previous reports have speculated on the effect of polyamines on bacterial biofilm formation. However, the regulation of biofilm formation by polyamines in Escherichia coli has not yet been assessed. The identification of polyamines that stimulate biofilm formation is important for developing novel therapies for biofilm-forming pathogens. This study sheds light on biofilm regulation in E. coli Our findings provide conclusive evidence that only spermidine can stimulate biofilm formation in E. coli cells, not putrescine or cadaverine. Last, ΔpotD inhibits biofilm formation even though the spermidine is synthesized inside the cells from putrescine. Since PotD is significant for biofilm formation and there is no ortholog of the PotABCD transporter in humans, PotD could be a target for the development of biofilm inhibitors.}, } @article {pmid33684823, year = {2021}, author = {Edefell, E and Falås, P and Torresi, E and Hagman, M and Cimbritz, M and Bester, K and Christensson, M}, title = {Promoting the degradation of organic micropollutants in tertiary moving bed biofilm reactors by controlling growth and redox conditions.}, journal = {Journal of hazardous materials}, volume = {414}, number = {}, pages = {125535}, doi = {10.1016/j.jhazmat.2021.125535}, pmid = {33684823}, issn = {1873-3336}, mesh = {*Biofilms ; Bioreactors ; Oxidation-Reduction ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {A novel process configuration was designed to increase biofilm growth in tertiary moving bed biofilm reactors (MBBRs) by providing additional substrate from primary treated wastewater in a sidestream reactor under different redox conditions in order to improve micropollutant removal in MBBRs with low substrate availability. This novel recirculating MBBR was operated on pilot scale for 13 months, and a systematic increase was seen in the biomass concentration and the micropollutant degradation rates, compared to a tertiary MBBR without additional substrate. The degradation rates per unit carrier surface area increased in the order of ten times, and for certain micropollutants, such as atenolol, metoprolol, trimethoprim and roxithromycin, the degradation rates increased 20-60 times. Aerobic conditions were critical for maintaining high micropollutant degradation rates. With innovative MBBR configurations it may be possible to improve the biological degradation of organic micropollutants in wastewater. It is suggested that degradation rates be normalized to the carrier surface area, in favor of the biomass concentration, as this reflects the diffusion limitations of oxygen, and will facilitate the comparison of different biofilm systems.}, } @article {pmid33684638, year = {2021}, author = {Zhang, N and Zhang, S and Ren, W and Gong, X and Long, H and Zhang, X and Cai, X and Huang, A and Xie, Z}, title = {Roles of rpoN in biofilm formation of Vibrio alginolyticus HN08155 at different cell densities.}, journal = {Microbiological research}, volume = {247}, number = {}, pages = {126728}, doi = {10.1016/j.micres.2021.126728}, pmid = {33684638}, issn = {1618-0623}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cell Count ; Flagella ; Gene Expression Regulation, Bacterial ; Phenotype ; Polysaccharides ; RNA Polymerase Sigma 54/genetics ; Vibrio alginolyticus/*genetics/growth & development/*metabolism ; }, abstract = {RpoN (δ54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ΔrpoN, complementary strain ΔrpoN-C and negative control strain ΔrpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ΔrpoN and ΔrpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ΔrpoN and ΔrpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It's worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.}, } @article {pmid33683248, year = {2021}, author = {Souza-Egipsy, V and Vega, JF and González-Toril, E and Aguilera, Á}, title = {Biofilm mechanics in an extremely acidic environment: microbiological significance.}, journal = {Soft matter}, volume = {17}, number = {13}, pages = {3672-3680}, doi = {10.1039/d0sm01975e}, pmid = {33683248}, issn = {1744-6848}, mesh = {Bacteria ; Biofilms ; *Chlorella ; Spain ; Viscosity ; }, abstract = {A variety of natural biofilms were collected from an extremely acidic environment at Río Tinto (Spain). In order to provide insights into the structure-function relationship, the microstructure of the biofilms was explored using low temperature scanning electron microscopy (LTSEM) in combination with rheological analysis. The creep-recovery experiment results have demonstrated the typical behaviour of viscoelastic materials that combine both elastic and viscous characters. The LTSEM visualization and rheological characterization of biofilms revealed that the network density increased in bacterial biofilms and was the lowest in protist Euglena biofilms. This means that, in the latter biofilms, a lower density of interactions exist, suggesting that the whole system experiences enhanced mobility under external mechanical stress. The samples with the highest dynamic moduli (Leptospirillum-Acidiphilium, Zygnemopsis, Chlorella and Cyanidium) have shown the typical strain thinning behaviour, whereas the Pinnularia and Euglena biofilms exhibited a viscous thickening reaction. The Zygnemopsis filamentous floating structure has the highest cohesive energy and has shown distinctive enhanced resilience and connectivity. This suggests that biofilms should be viewed as soft viscoelastic systems the properties of which are determined by the main organisms and their extracellular polymeric substances. The fractional Maxwell model has been found to explain the rheological behaviour of the observed complex quite well, particularly the power-law behaviour and the characteristic broad relaxation response of these systems.}, } @article {pmid33682623, year = {2021}, author = {Vila, T and Kong, EF and Montelongo-Jauregui, D and Van Dijck, P and Shetty, AC and McCracken, C and Bruno, VM and Jabra-Rizk, MA}, title = {Therapeutic implications of C. albicans-S. aureus mixed biofilm in a murine subcutaneous catheter model of polymicrobial infection.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {835-851}, pmid = {33682623}, issn = {2150-5608}, support = {R01 AI130170/AI/NIAID NIH HHS/United States ; U19 AI110820/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/genetics ; Catheter-Related Infections/*drug therapy/microbiology ; Catheters/microbiology ; Coinfection/*drug therapy/*microbiology ; Disease Models, Animal ; Female ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/genetics ; Virulence Factors ; }, abstract = {Biofilm-associated polymicrobial infections tend to be challenging to treat. Candida albicans and Staphylococcus aureus are leading pathogens due to their ability to form biofilms on medical devices. However, the therapeutic implications of their interactions in a host is largely unexplored. In this study, we used a mouse subcutaneous catheter model for in vivo-grown polymicrobial biofilms to validate our in vitro findings on C. albicans-mediated enhanced S. aureus tolerance to vancomycin in vivo. Comparative assessment of S. aureus recovery from catheters with single- or mixed-species infection demonstrated failure of vancomycin against S. aureus in mice with co-infected catheters. To provide some mechanistic insights, RNA-seq analysis was performed on catheter biofilms to delineate transcriptional modulations during polymicrobial infections. C. albicans induced the activation of the S. aureus biofilm formation network via down-regulation of the lrg operon, repressor of autolysis, and up-regulation of the ica operon and production of polysaccharide intercellular adhesin (PIA), indicating an increase in eDNA production, and extracellular polysaccharide matrix, respectively. Interestingly, virulence factors important for disseminated infections, and superantigen-like proteins were down-regulated during mixed-species infection, whereas capsular polysaccharide genes were up-regulated, signifying a strategy favoring survival, persistence and host immune evasion. In vitro follow-up experiments using DNA enzymatic digestion, lrg operon mutant strains, and confocal scanning microscopy confirmed the role of C. albicans-mediated enhanced eDNA production in mixed-biofilms on S. aureus tolerance to vancomycin. Combined, these findings provide mechanistic insights into the therapeutic implications of interspecies interactions, underscoring the need for novel strategies to overcome limitations of current therapies.}, } @article {pmid33682541, year = {2021}, author = {Luo, HZ and Zhou, JW and Sun, B and Jiang, H and Tang, S and Jia, AQ}, title = {Inhibitory effect of norharmane on Serratia marcescens NJ01 quorum sensing-mediated virulence factors and biofilm formation.}, journal = {Biofouling}, volume = {37}, number = {2}, pages = {145-160}, doi = {10.1080/08927014.2021.1874942}, pmid = {33682541}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Carbolines/pharmacology ; *Quorum Sensing ; *Serratia marcescens/genetics ; Spectroscopy, Fourier Transform Infrared ; Virulence Factors/genetics ; }, abstract = {Serratia marcescens NJ01, a Gram-negative bacterium, can infect tomato leaves and cause chlorosis and wilting. The present study evaluated the quorum sensing (QS) and biofilm inhibitory effects of seven carboline compounds against S. marcescens NJ01 at 20 μg ml[-1], and subsequently focused the study on norharmane as this had the best inhibitory activity. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed the down-regulation of QS and biofilm related genes bsmA, bsmB, fimA, fimC, flhD, pigA, pigC and shlA on exposure to norharmane. Fourier-Transform Infrared Spectroscopy (FT-IR) analysis showed a reduction in the major components of the exopolysaccharide (EPS) matrix such as nucleic acids, proteins and fatty acids, which are involved in forming the tertiary structure of biofilms. Norharmane exposure also enhanced the susceptibility of the biofilm to ofloxacin. Hence, norharmane has the potential for use as an antibiotic adjuvant to enhance the efficacy of conventional antibiotics to reduce pathogenic bacterial infections.}, } @article {pmid33682160, year = {2021}, author = {Wang, X and Zhang, D and Dong, F and Liu, S and Zhang, J and Zhao, H}, title = {Cell differentiation and motion determine the Bacillus subtilis biofilm morphological evolution under the competitive growth.}, journal = {Journal of basic microbiology}, volume = {61}, number = {5}, pages = {396-405}, doi = {10.1002/jobm.202000635}, pmid = {33682160}, issn = {1521-4028}, support = {11772047//National Natural Science Foundation of China/ ; 11972074//National Natural Science Foundation of China/ ; 11620101001//National Natural Science Foundation of China/ ; }, mesh = {Bacillus subtilis/*genetics/*physiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Optical Imaging/*methods ; *Phenotype ; }, abstract = {The growth discrepancy of Bacillus subtilis biofilms along different directions under the competitive growth drive the formation of anisotropic biofilm morphology directly. Two biofilms growing from two inoculating positions with different distances exhibit promoting or inhibiting growth behavior. Here we develop an optical imaging technology to observe the cell differentiation and the growth dynamics when the biofilm grows. It shows that the spatiotemporal distribution of different phenotypes affects the biofilm morphological evolution. We develop a program to calculate the velocity of cell motion within the biofilm, which is based on the feature point matching approach. We find the cell differentiation ununiformity in the neighboring region and its opposite region leads to the cell velocity difference in the competitive environment, the different cell motion further influences the biofilm morphology evolution. When biofilms grow with a long inoculating distance, there is always a gap between the them; when biofilms grow with a short inoculating distance, two biofilms gradually merge into a whole. Our work establishes a relationship between microscopic cells and macroscopic biofilm morphological which enables us to study the competitive growth process of biofilms from multiple perspectives.}, } @article {pmid33681595, year = {2021}, author = {Shahid, M and Manoharadas, S and Altaf, M and Alrefaei, AF}, title = {Organochlorine Pesticides Negatively Influenced the Cellular Growth, Morphostructure, Cell Viability, and Biofilm-Formation and Phosphate-Solubilization Activities of Enterobacter cloacae Strain EAM 35.}, journal = {ACS omega}, volume = {6}, number = {8}, pages = {5548-5559}, pmid = {33681595}, issn = {2470-1343}, abstract = {An in vitro study was conducted to assess the impact of organochlorine pesticides (OCPs) on cellular growth, morphology, cell viability, biofilm-formation activity, and growth-regulating substances of a soil bacterium. Phosphate-solubilizing EAM 35 isolated from rhizosphere soil was molecularly identified as Enterobacter cloacae (accession number MT672578.1). Strain EAM 35 tolerated varying levels of OCPs, viz., benzene hexachloride (BHC), chlorpyrifos (CP), dieldrin (DE), and endosulfan (ES). The toxicity of OCPs to strain EAM 35 was displayed in a concentration-dependent manner. Among the OCPs, ES at a concentration of 200 μM showed a higher toxicity, where it maximally reduced the bacterial synthesis of indole-3-acetic acid (IAA), salicylic acid (SA), and 2,3-dihydroxy-benzoic acid (DHBA) by 73% (p ≤ 0.001), 85% (p ≤ 0.005), and 83% (p ≤ 0.001), respectively, over the control. While comparing the toxicity of OCPs to P-solubilizing activity of E. cloacae after 10 days of growth, the toxicity pattern followed the order ES (mean value = 82.6 μg mL[-1]) > CP (mean value = 93.2 μg mL[-1]) > DE (mean value = 113.6 μg mL[-1]) > BHC (mean value = 127 μg mL[-1]). Furthermore, OCP-induced surface morphological distortion in E. cloacae EAM 35 was observed as gaps, pits on both cellular facets, and fragmented and disorganized cell structure under a scanning electron microscope (SEM). The membrane-compromised cells increased as the concentrations of OC pesticides increased from 25 to 200 μM. Additionally, microbial counts (log10 CFU/mL) were also affected after pesticide exposure and decreased with increasing concentrations. While assessing the impact of OCPs on inhibition (%) of log10 CFU/mL, 150, 175, and 200 μM concentrations of ES completely reduced the growth of E. cloacae. Similarly, while comparing the toxicity of higher concentrations of OCPs to bacterial growth, sensitivity followed the order ES > DE > CP > BHC. In addition, the biofilm-formation ability of strain EAM 35 was inhibited in a pesticide-dose-dependent manner, and it was statistically (p ≤ 0.05, p ≤ 0.005, and p ≤ 0.001) significant. Conclusively, the present study clearly suggests that before applying pesticides to soil, their recommended dose should carefully be monitored.}, } @article {pmid33680986, year = {2021}, author = {He, Y and Na, R and Niu, X and Xiao, B and Yang, H}, title = {Lactobacillus rhamnosus and Lactobacillus casei Affect Various Stages of Gardnerella Species Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {11}, number = {}, pages = {568178}, pmid = {33680986}, issn = {2235-2988}, mesh = {Biofilms ; Female ; Gardnerella ; Gardnerella vaginalis ; Humans ; *Lacticaseibacillus casei ; *Lacticaseibacillus rhamnosus ; *Probiotics ; Vagina ; }, abstract = {Bacterial vaginosis (BV) and its recurrence are most commonly associated with the formation of Gardnerella species biofilm. Probiotics are typically used to treat BV; however, the optimal period of Lactobacillus probiotic application in BV treatment remains uncertain. The present study aimed to explore the effects of Lactobacillus rhamnosus and Lactobacillus casei on various stages of biofilm formation in Gardnerella species. The biofilm-forming ability of seven strains, including one Gardnerella vaginalis ATCC 14018 and six clinically isolated Gardnerella species, was determined via gentian violet staining assay. Moreover, the sensitivity of the planktonic and biofilm forms toward metronidazole and clindamycin was assessed via microdilution broth method. L. rhamnosus Xbb-LR-1 and L. casei Xbb-LC-1 were added during various stages of biofilm formation in Gardnerella species and were cocultured for 24 h. The biofilm thickness of each sample was determined via confocal laser scanning microscopy (CLSM). The absolute quantities of Gardnerella species in each sample was obtained via real time polymerase chain reaction method, and the pH value was obtained using a pH indicator paper. Biofilm formation by Gardnerella species in a medium with distinct pH values was observed via gentian violet staining, CLSM, and scanning electron microscopy (SEM). The biofilm increased the resistance of Gardnerella species toward metronidazole and clindamycin. L. rhamnosus added at the initial biofilm formation stage in Gardnerella species exhibited highest inhibitory effect, with a percentage inhibition of 38.17% ± 1.35%. When the pH value of the culture medium was <4.5 or >6.5, ATCC 14018 could hardly form a biofilm; however, at pH ≥4.5 and ≤6.5, it was able to form a stronger biofilm. The amount of biofilm attained maximum value at optical density of 3.29 ± 0.28 (595 nm), pH 5.5, and at 36 h. Biofilm formation increases the resistance of Gardnerella species toward antibiotics. Maintaining an acidic vaginal environment with pH <4.5 and a vaginal microbiota dominated by Lactobacillus remarkably prevents the formation of Gardnerella species biofilm at the initial stage, which further has a significant impact on the treatment and prevention of biofilm-related infections.}, } @article {pmid33680985, year = {2020}, author = {Kim, HE and Liu, Y and Dhall, A and Bawazir, M and Koo, H and Hwang, G}, title = {Synergism of Streptococcus mutans and Candida albicans Reinforces Biofilm Maturation and Acidogenicity in Saliva: An In Vitro Study.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {623980}, pmid = {33680985}, issn = {2235-2988}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE027970/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; Candida albicans ; Child, Preschool ; *Dental Caries ; Humans ; Saliva ; *Streptococcus mutans ; }, abstract = {Early childhood caries, a virulent-form of dental caries, is painful, difficult, and costly to treat that has been associated with high levels of Streptococcus mutans (Sm) and Candida albicans (Ca) in plaque-biofilms on teeth. These microorganisms appear to develop a symbiotic cross-kingdom interaction that amplifies the virulence of plaque-biofilms. Although biofilm studies reveal synergistic bacterial-fungal association, how these organisms modulate cross-kingdom biofilm formation and enhance its virulence in the presence of saliva remain largely unknown. Here, we compared the properties of Sm and Sm-Ca biofilms cultured in saliva by examining the biofilm structural organization and capability to sustain an acidic pH environment conducive to enamel demineralization. Intriguingly, Sm-Ca biofilm is rapidly matured and maintained acidic pH-values (~4.3), while Sm biofilm development was retarded and failed to create an acidic environment when cultured in saliva. In turn, the human enamel slab surface was severely demineralized by Sm-Ca biofilms, while there was minimal damage to the enamel surface by Sm biofilm. Interestingly, Sm-Ca biofilms exhibited an acidic environment regardless of their hyphal formation ability. Our data reveal the critical role of symbiotic interaction between S. mutans and C. albicans in human saliva in the context of pathogenesis of dental caries, which may explain how the cross-kingdom interaction contributes to enhanced virulence of plaque-biofilm in the oral cavity.}, } @article {pmid33679639, year = {2021}, author = {Tazehabadi, MH and Algburi, A and Popov, IV and Ermakov, AM and Chistyakov, VA and Prazdnova, EV and Weeks, R and Chikindas, ML}, title = {Probiotic Bacilli Inhibit Salmonella Biofilm Formation Without Killing Planktonic Cells.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {615328}, pmid = {33679639}, issn = {1664-302X}, abstract = {Salmonellosis is a foodborne infection caused by Salmonella. Domestic poultry species are one of the main reservoirs of Salmonella, which causes the foodborne infection salmonellosis, and are responsible for many cases of animal-to-human transmission. Keeping backyard chickens is now a growing trend, increasing the frequency of direct contact with the flock and, by consequence, the incidence of Salmonella infections. Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 are probiotic bacilli that produce the bacteriocins subtilosin A and subtilin, respectively. The antimicrobial activity of the two strains was determined against the reference strain Micrococcus luteus ATCC 10420. The cell-free supernatant of B. subtilis KATMIRA1933 inhibited biofilm formation by Salmonella enterica subsp. enterica serovar Hadar, Salmonella enterica subsp. enterica serovar Enteritidis phage type 4, and Salmonella enterica subsp. enterica serovar Thompson by 51.1, 48.3, and 56.9%, respectively. The cell-free supernatant of B. amyloliquefaciens B-1895 inhibited the biofilm formation of these Salmonella strains by 30.4, 28.6, and 35.5%, respectively. These findings suggest that the bacillus strains may have the potential to be used as probiotics and antibiotic alternatives for the control of Salmonella in poultry. The number of planktonic cells was unaffected by treatment with the cell-free supernatant. A co-culture of the Salmonella strains with either bacilli showed no signs of growth inhibition, suggesting that it might have been quorum sensing that is affected by the two Bacillus strains.}, } @article {pmid33679628, year = {2021}, author = {Coclet, C and Garnier, C and D'Onofrio, S and Durrieu, G and Pasero, E and Le Poupon, C and Omanović, D and Mullot, JU and Misson, B and Briand, JF}, title = {Trace Metal Contamination Impacts Predicted Functions More Than Structure of Marine Prokaryotic Biofilm Communities in an Anthropized Coastal Area.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {589948}, pmid = {33679628}, issn = {1664-302X}, abstract = {Trace metal (TM) contamination in marine coastal areas is a worldwide threat for aquatic communities. However, little is known about the influence of a multi-chemical contamination on both marine biofilm communities' structure and functioning. To determine how TM contamination potentially impacted microbial biofilms' structure and their functions, polycarbonate (PC) plates were immerged in both surface and bottom of the seawater column, at five sites, along strong TM contamination gradients, in Toulon Bay. The PC plates were incubated during 4 weeks to enable colonization by biofilm-forming microorganisms on artificial surfaces. Biofilms from the PC plates, as well as surrounding seawaters, were collected and analyzed by 16S rRNA amplicon gene sequencing to describe prokaryotic community diversity, structure and functions, and to determine the relationships between bacterioplankton and biofilm communities. Our results showed that prokaryotic biofilm structure was not significantly affected by the measured environmental variables, while the functional profiles of biofilms were significantly impacted by Cu, Mn, Zn, and salinity. Biofilms from the contaminated sites were dominated by tolerant taxa to contaminants and specialized hydrocarbon-degrading microorganisms. Functions related to major xenobiotics biodegradation and metabolism, such as methane metabolism, degradation of aromatic compounds, and benzoate degradation, as well as functions involved in quorum sensing signaling, extracellular polymeric substances (EPS) matrix, and biofilm formation were significantly over-represented in the contaminated site relative to the uncontaminated one. Taken together, our results suggest that biofilms may be able to survive to strong multi-chemical contamination because of the presence of tolerant taxa in biofilms, as well as the functional responses of biofilm communities. Moreover, biofilm communities exhibited significant variations of structure and functional profiles along the seawater column, potentially explained by the contribution of taxa from surrounding sediments. Finally, we found that both structure and functions were significantly distinct between the biofilm and bacterioplankton, highlighting major differences between the both lifestyles, and the divergence of their responses facing to a multi-chemical contamination.}, } @article {pmid33679103, year = {2021}, author = {Niazy, AA}, title = {LuxS quorum sensing system and biofilm formation of oral microflora: A short review article.}, journal = {The Saudi dental journal}, volume = {33}, number = {3}, pages = {116-123}, pmid = {33679103}, issn = {1013-9052}, abstract = {The LuxS quorum sensing system is considered as the main system that most of the oral bacteria use to communicate in order to create biofilms. Here we identified 11 of the most important biofilm formers that utilize the LuxS system and presented current and recent information regarding this system. Though different bacterial species are able to communicate thorough the LuxS system, it was also found that cross kingdom communication can occur between bacteria and fungi and bacteria and epithelial cells. Immune response also plays and important role in mitigating the effects of biofilms. Here we identified 6 of the most important molecules that are involved in the immune response to biofilms. These immune molecules maintain the stability in the oral cavity by preventing bacteria from overwhelming the space and simultaneously minimizing the immune response in order not to cause tissue damage. Here we also discuss current research being done in order to maintain the balance in the oral cavity via inhibiting biofilm formation without eradicating oral bacteria in order to prevent the overgrowth of other organisms such as Candida albicans. One approach being used is inhibiting AI-2 intermediates which leads to lack of quorum sensing communication between bacteria through the use of intermediate analogues. Another approach that found success is the utilization of D forms of sugars where D-ribose and D-galactose have been proven to inhibit the LuxS system and subsequently preventing the process of quorum sensing leading to the reduction in biofilm formation.}, } @article {pmid33678731, year = {2021}, author = {Feitosa, S and Carreiro, AFP and Martins, VM and Platt, JA and Duarte, S}, title = {Effect of a chlorhexidine-encapsulated nanotube modified pit-and-fissure sealant on oral biofilm.}, journal = {Dental materials journal}, volume = {40}, number = {3}, pages = {758-765}, doi = {10.4012/dmj.2020-241}, pmid = {33678731}, issn = {1881-1361}, mesh = {Biofilms ; Chlorhexidine/pharmacology ; Materials Testing ; *Nanotubes ; *Pit and Fissure Sealants ; }, abstract = {The purpose of this study was to characterize a chlorhexidine-encapsulated nanotube modified pit-and-fissure sealant for biofilm development prevention. HS (commercial control); HNT (HS+15wt%Halloysite[®]-clay-nanotube); CHX10% (HS+15wt% HNT-encapsulated with chlorhexidine 10%); and CHX20% (HS+15wt% HNT-encapsulated with CHX20%) were tested. Degree-of-conversion (DC%), Knoop hardness (KHN), and viscosity were analyzed. The ability of the sealant to wet the fissures was evaluated. Specimens were tested for zones of inhibition of microbial growth. S. mutans biofilm was tested by measuring recovered viability. Data were statistically analyzed (p<0.05). DC% was significantly higher for the HNT-CHX groups. For KHN, CHX10% presented a lower mean value than the other groups. Adding HNT resulted in higher viscosity values. The biofilm on CHX10% and CHX20% sealants presented remarkable CFU/mL reduction in comparison to the HS. The experimental material was able to reduce the biofilm development in S. mutans biofilm without compromising the sealant properties.}, } @article {pmid33677357, year = {2021}, author = {Deng, Y and Liu, SY and Chua, SL and Khoo, BL}, title = {The effects of biofilms on tumor progression in a 3D cancer-biofilm microfluidic model.}, journal = {Biosensors & bioelectronics}, volume = {180}, number = {}, pages = {113113}, doi = {10.1016/j.bios.2021.113113}, pmid = {33677357}, issn = {1873-4235}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Biosensing Techniques ; Ciprofloxacin ; Microfluidics ; *Neoplasms ; *Uropathogenic Escherichia coli ; }, abstract = {Components within the tumor microenvironment, such as intratumoral bacteria (IB; within tumors), affect tumor progression. However, current experimental models have not explored the effects of extratumoral bacteria (EB; outside tumors) on cancer progression. Here, we developed a microfluidic platform to analyze the influence of bacterial distribution on bladder cancer progression under defined conditions, using uropathogenic Escherichia coli. This was achieved by establishing coating (CT) and colonizing (CL) models to simulate the different invasion and colonization modes of IB and EB in tumor tissues. We demonstrated that both EB and IB induced closer cell-cell contacts within the tumor cluster, but cancer cell viability was reduced only in the presence of IB. Interestingly, cancer stem cell counts increased significantly in the presence of EB. These outcomes were due to the formation of extracellular DNA-based biofilms by EB. Triple therapy of DNase (anti-biofilm agent), ciprofloxacin (antibiotic), and doxorubicin (anti-cancer drug) could effectively eradicate biofilms and tumors simultaneously. Our preclinical proof-of-concept provides insights on how bacteria can influence tumor progression and facilitate future research on anti-biofilm cancer management therapies.}, } @article {pmid33675236, year = {2021}, author = {Calvo, DC and Ontiveros-Valencia, A and Krajmalnik-Brown, R and Torres, CI and Rittmann, BE}, title = {Carboxylates and alcohols production in an autotrophic hydrogen-based membrane biofilm reactor.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {6}, pages = {2338-2347}, doi = {10.1002/bit.27745}, pmid = {33675236}, issn = {1097-0290}, mesh = {Alcohols/*metabolism ; Autotrophic Processes ; Bacteria/metabolism ; Bacteria, Anaerobic/*metabolism ; Biofilms ; *Bioreactors ; Carbon/metabolism ; Carboxylic Acids/*metabolism ; Hydrogen ; Industrial Microbiology ; Membranes ; Microbiota ; }, abstract = {Microbiological conversion of CO2 into biofuels and/or organic industrial feedstock is an excellent carbon-cycling strategy. Here, autotrophic anaerobic bacteria in the membrane biofilm reactor (MBfR) transferred electrons from hydrogen gas (H2) to inorganic carbon (IC) and produced organic acids and alcohols. We systematically varied the H2 -delivery, the IC concentration, and the hydraulic retention time in the MBfR. The relative availability of H2 versus IC was the determining factor for enabling microbial chain elongation (MCE). When the H2 :IC mole ratio was high (>2.0 mol H2 /mol C), MCE was an important process, generating medium-chain carboxylates up to octanoate (C8, 9.1 ± 1.3 mM C and 28.1 ± 4.1 mmol C m[-2] d[-1]). Conversely, products with two carbons were the only ones present when the H2 :IC ratio was low (<2.0 mol H2 /mol C), so that H2 was the limiting factor. The biofilm microbial community was enriched in phylotypes most similar to the well-known acetogen Acetobacterium for all conditions tested, but phylotypes closely related with families capable of MCE (e.g., Bacteroidales, Rhodocyclaceae, Alcaligenaceae, Thermoanaerobacteriales, and Erysipelotrichaceae) became important when the H2 :IC ratio was high. Thus, proper management of IC availability and H2 supply allowed control over community structure and function, reflected by the chain length of the carboxylates and alcohols produced in the MBfR.}, } @article {pmid33675008, year = {2021}, author = {Matias, RR and Sepúlveda, AMG and Batista, BN and de Lucena, JMVM and Albuquerque, PM}, title = {Degradation of Staphylococcus aureus Biofilm Using Hydrolytic Enzymes Produced by Amazonian Endophytic Fungi.}, journal = {Applied biochemistry and biotechnology}, volume = {193}, number = {7}, pages = {2145-2161}, pmid = {33675008}, issn = {1559-0291}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Fungal Proteins/*pharmacology ; Fungi/*enzymology ; Myrtaceae/microbiology ; Peptide Hydrolases/*pharmacology ; Staphylococcus aureus/*physiology ; }, abstract = {Microbial biofilms can cause serious health problems, since, due to their persistent character, they often function as spreaders of contaminants. Hydrolytic enzymes have a number of industrial applications and have been indicated as an alternative to the traditional chemical methods that are used to eradicate microbial biofilms. In this study, we evaluated the ability of enzymatic extracts produced by endophytic fungi isolated from the Amazonian species Myrcia guianensis to remove Staphylococcus aureus biofilms. After culture in liquid medium, the fungal hydrolytic extracts showed amylase (3.77 U/mL), lipase (3.84 U/mL), protease (3.63 U/mL), and xylanase (2.91 U/mL) activity. A 24 h mature S. aureus ATCC6538 biofilm was exposed to each enzyme extract with standardized enzyme activities for 10, 30, and 60 min. The optical density at 630 nm was used to calculate the growth rate (GR%) and the residual biofilm rate (RBR%). The most promising solutions were used in combination, based on a 2[4] factorial design for 0, 10, 20, and 30 min of exposure. Lipase and protease solutions, when applied separately, were the most effective, and promoted the complete removal of S. aureus biofilms in t10 (lipase) and t30 and t60 (lipase and protease). Of the combined treatments using 1.0 U/mL protease and 0.4 U/mL lipase, total biofilm degradation was observed for all exposure times. Thus, the hydrolases produced by the Amazonian endophytic fungi evaluated here are highlighted as an interesting tool in the fight against microbial biofilms.}, } @article {pmid33673668, year = {2021}, author = {Tang, Y and Bai, J and Yang, Y and Bai, X and Bello-Onaghise, G and Xu, Y and Li, Y}, title = {Effect of Syringopicroside Extracted from Syringa oblata Lindl on the Biofilm Formation of Streptococcus suis.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {5}, pages = {}, pmid = {33673668}, issn = {1420-3049}, support = {NO. 31600276//National Natural Science Foundation of China/ ; NO. C2018013//Natural Science Foundation of Heilongjiang Province of China/ ; LBH-Q19010, LBH-Q17030//Postdoctoral Scientific Research Start-up Fund Project of Heilongjiang Province of China/ ; }, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Drug Evaluation, Preclinical ; Glycosides/*chemistry/pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Plant Extracts/*chemistry/pharmacology ; Streptococcus suis/*drug effects ; Syringa/*chemistry ; Temperature ; Time Factors ; Ultrasonics ; }, abstract = {Syringopicroside is a natural drug with antibacterial activity, which is the main ingredient of Syringa oblata Lindl (S. oblata). In order to further develop the application of S. oblata and evaluate the ability of syringopicroside against Streptococcus suis (S. suis), this investigation first applied an ultrasonic-assisted method to extract syringopicroside, and then response surface methodology (RSM) was performed to get the optimum condition. Based on RSM analysis, a second-order polynomial equation about the syringopicroside yield and four variables, including ultrasonic power, time, temperature, and liquid-to-solid ratio, was purposed. Through RSM prediction and model verification experiments, the optimum conditions were determined, as follows: ultrasonic time was 63 min, temperature was 60 °C, a liquid-to-solid ratio was set to 63 mL/g, and ultrasonic power was 835 W. Under this condition, a high syringopicroside yield was obtained (3.07 ± 0.13 mg/g), which was not significantly different with a predicated value. After separation and purification by HPD 500 microporous resin, then mass spectrum was applied to identify the main ingredient in aqueous extract. A minimal inhibitory concentration (MIC) assay revealed the value against S. suis of syringopicroside was 2.56 µg/µL and syringopicroside with sub-inhibitory concentrations that could effectively inhibit biofilm formation of S. suis. Besides, scanning electron microscopy analysis indicated syringopicroside could destroy the multi-layered aggregation structure of S. suis. Finally, molecular docking analysis confirmed that syringopicroside was combined with Orfy protein of S. suis through hydrogen bonds, hydrophobic interaction, and π-π stacking.}, } @article {pmid33673438, year = {2021}, author = {Hwang, G and Blatz, MB and Wolff, MS and Steier, L}, title = {Diagnosis of Biofilm-Associated Peri-Implant Disease Using a Fluorescence-Based Approach.}, journal = {Dentistry journal}, volume = {9}, number = {3}, pages = {}, pmid = {33673438}, issn = {2304-6767}, support = {R01 DE027970/DE/NIDCR NIH HHS/United States ; DE027970/DE/NIDCR NIH HHS/United States ; }, abstract = {Dental implants have become a routine component of daily dental practice and the demand for dental implants is expected to increase significantly in the future. Despite the high success rates of dental implants, failures do occur, resulting in discomfort, rampant destruction of the oral health, or painful and costly surgical replacement of a failed implant. Peri-implant diseases are inflammatory conditions affecting the soft/hard tissues surrounding a functional dental implant. Plenty of experimental evidence indicates that the accumulation of dental plaque at the soft tissue-implant interface and the subsequent local inflammatory response seems to be key in the pathogenesis of the peri-implant mucositis. Such peri-implant-soft tissue interface is less effective than natural teeth in resisting bacterial invasion, enhancing vulnerability to subsequent peri-implant disease. Furthermore, in certain individuals, it will progress to peri-implantitis, resulting in alveolar bone loss and implant failure. Although early diagnosis and accurate identification of risk factors are extremely important to effectively prevent peri-implant diseases, current systematic reviews revealed that a uniform classification and diagnostic methodology for peri-implantitis are lacking. Recent progress on fluorescence-based technology enabled rapid diagnosis of the disease and effective removal of plaques. Here, we briefly review biofilm-associated peri-implant diseases and propose a fluorescence-based approach for more accurate and objective diagnoses. A fluorescence-based diagnosis tool through headlights combined with special-filtered dental loupes may serve as a hands-free solution for both precise diagnosis and effective removal of plaque-biofilms.}, } @article {pmid33673016, year = {2021}, author = {Rezk, AI and Park, J and Moon, JY and Lee, S and Park, CH and Kim, CS}, title = {A Novel Design of Tri-Layer Membrane with Controlled Delivery of Paclitaxel and Anti-Biofilm Effect for Biliary Stent Applications.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {11}, number = {2}, pages = {}, pmid = {33673016}, issn = {2079-4991}, abstract = {Here, we developed a novel biliary stent coating material that is composed of tri-layer membrane with dual function of sustained release of paclitaxel (PTX) anticancer drug and antibacterial effect. The advantages of using electrospinning technique were considered for the even distribution of PTX and controlled release profile from the nanofiber mat. Furthermore, film cast method was utilized to fabricate AgNPs-immobilized PU film to direct the release towards the tumor site and suppress the biofilm formation. The in vitro antibacterial test conducted against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria species showed excellent antibacterial effect. The in vitro drug release study confirmed the sustained release of PTX from the tri-layer membrane and the release profile fitted first order with correlation coefficient of R[2] = 0.98. Furthermore, the release mechanism was studied using Korsmeyer-Peppas model, revealing that the release mechanism follows Fickian diffusion. Based on the results, this novel tri-layer membrane shows curative potential in clinical development.}, } @article {pmid33672911, year = {2021}, author = {Sato, K and Naya, M and Hatano, Y and Kondo, Y and Sato, M and Nagano, K and Chen, S and Naito, M and Sato, C}, title = {Biofilm Spreading by the Adhesin-Dependent Gliding Motility of Flavobacterium johnsoniae. 1. Internal Structure of the Biofilm.}, journal = {International journal of molecular sciences}, volume = {22}, number = {4}, pages = {}, pmid = {33672911}, issn = {1422-0067}, support = {16K11450//JSPS KAKENHI Grants/ ; 19K10091//JSPS KAKENHI Grants/ ; R3721884//NIAID grant/ ; 15K14499//JSPS KAKENHI Grants/ ; }, mesh = {Adhesins, Bacterial/*metabolism ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Flavobacterium/genetics/*physiology/ultrastructure ; Locomotion/genetics/*physiology ; Microscopy, Electron, Transmission/methods ; Microscopy, Fluorescence/methods ; Mutation ; Time-Lapse Imaging/methods ; }, abstract = {The Gram-negative bacterium Flavobacterium johnsoniae employs gliding motility to move rapidly over solid surfaces. Gliding involves the movement of the adhesin SprB along the cell surface. F. johnsoniae spreads on nutrient-poor 1% agar-PY2, forming a thin film-like colony. We used electron microscopy and time-lapse fluorescence microscopy to investigate the structure of colonies formed by wild-type (WT) F. johnsoniae and by the sprB mutant (ΔsprB). In both cases, the bacteria were buried in the extracellular polymeric matrix (EPM) covering the top of the colony. In the spreading WT colonies, the EPM included a thick fiber framework and vesicles, revealing the formation of a biofilm, which is probably required for the spreading movement. Specific paths that were followed by bacterial clusters were observed at the leading edge of colonies, and abundant vesicle secretion and subsequent matrix formation were suggested. EPM-free channels were formed in upward biofilm protrusions, probably for cell migration. In the nonspreading ΔsprB colonies, cells were tightly packed in layers and the intercellular space was occupied by less matrix, indicating immature biofilm. This result suggests that SprB is not necessary for biofilm formation. We conclude that F. johnsoniae cells use gliding motility to spread and maturate biofilms.}, } @article {pmid33672862, year = {2021}, author = {Song, S and Wood, TK}, title = {The Primary Physiological Roles of Autoinducer 2 in Escherichia coli Are Chemotaxis and Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33672862}, issn = {2076-2607}, abstract = {Autoinducer 2 (AI-2) is a ubiquitous metabolite but, instead of acting as a "universal signal," relatively few phenotypes have been associated with it, and many scientists believe AI-2 is often a metabolic byproduct rather than a signal. Here, the aim is to present evidence that AI-2 influences both biofilm formation and motility (swarming and chemotaxis), using Escherichia coli as the model system, to establish AI-2 as a true signal with an important physiological role in this bacterium. In addition, AI-2 signaling is compared to the other primary signal of E. coli, indole, and it is shown that they have opposite effects on biofilm formation and virulence.}, } @article {pmid33672820, year = {2021}, author = {Liu, Z and Li, L and Wang, Q and Sadiq, FA and Lee, Y and Zhao, J and Zhang, H and Chen, W and Li, H and Lu, W}, title = {Transcriptome Analysis Reveals the Genes Involved in Bifidobacterium Longum FGSZY16M3 Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33672820}, issn = {2076-2607}, support = {31871774//The National Nature Science Foundation of China/ ; 31820103010//The National Nature Science Foundation of China/ ; KYCX20_1878//Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; JUSRP51903B//The Fundamental Research Funds for the Central Universities/ ; BP0719028//111project/ ; No//International Cooperation Fund Pool Project of Jiangsu Industrial Technology Research Institute/ ; JUFSTR20180102//the collaborative innovation center of food safety and quality control in Jiangsu Province and the National First-class Discipline Program of Food Science and Technology/ ; }, abstract = {Biofilm formation has evolved as an adaptive strategy for bacteria to cope with harsh environmental conditions. Currently, little is known about the molecular mechanisms of biofilm formation in bifidobacteria. A time series transcriptome sequencing analysis of both biofilm and planktonic cells of Bifidobacterium longum FGSZY16M3 was performed to identify candidate genes involved in biofilm formation. Protein-protein interaction network analysis of 1296 differentially expressed genes during biofilm formation yielded 15 clusters of highly interconnected nodes, indicating that genes related to the SOS response (dnaK, groS, guaB, ruvA, recA, radA, recN, recF, pstA, and sufD) associated with the early stage of biofilm formation. Genes involved in extracellular polymeric substances were upregulated (epsH, epsK, efp, frr, pheT, rfbA, rfbJ, rfbP, rpmF, secY and yidC) in the stage of biofilm maturation. To further investigate the genes related to biofilm formation, weighted gene co-expression network analysis (WGCNA) was performed with 2032 transcript genes, leading to the identification of nine WGCNA modules and 133 genes associated with response to stress, regulation of gene expression, quorum sensing, and two-component system. These results indicate that biofilm formation in B. longum is a multifactorial process, involving stress response, structural development, and regulatory processes.}, } @article {pmid33672669, year = {2021}, author = {Tan, X and Xie, H and Zhang, B and Zhou, J and Dou, Z and Wang, X and Wang, N}, title = {A Novel Ivermectin-Derived Compound D4 and Its Antimicrobial/Biofilm Properties against MRSA.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33672669}, issn = {2079-6382}, support = {82002190//National Natural Science Foundation of China/ ; 2019A610196//Natural Science Foundation of Ningbo/ ; 421807120, 421906052, 422003802//Research Fund of Ningbo University/ ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) and its biofilms infection is still a serious threat to global health. It is urgent to develop efficient drugs by repositioning or designing drugs to solve this problem. In this study, the antibacterial/biofilm activity and mechanisms of ivermectin (D) and its 4″-position amino substitution derivative (D4) against MRSA were investigated. The minimum inhibitory concentration (MIC) of D was 20 μg/mL, which is four times higher than D4 (MIC = 5 μg/mL). The mechanism research demonstrated that D4 was more potent than D at destroying bacterial cell wall, permeating cell membrane (6.25-36.0% vs 1.92-6.04%) and binding to MRSA genomic DNA. Moreover, after incubation with 10-40 μg/mL D4 for 24 h, the percentages of biofilm decreased by 21.2-92.9%, which was more effective than D (no significant change at 40 μg/mL). The antibiofilm effect is achieved by regulating the expression of related genes (RSH, relQ, rsbU, sigB, spA, and icaD). Additionally, though the higher hemolysis makes D4 a safety risk for intravenous injection, other administration options could be considered as well. Therefore, all the results have indicated that D4 may be a potential candidate compound for the treatment of MRSA and its biofilm infections.}, } @article {pmid33672647, year = {2021}, author = {Castro, J and Rosca, AS and Muzny, CA and Cerca, N}, title = {Atopobium vaginae and Prevotella bivia Are Able to Incorporate and Influence Gene Expression in a Pre-Formed Gardnerella vaginalis Biofilm.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33672647}, issn = {2076-0817}, support = {R01 AI146065/AI/NIAID NIH HHS/United States ; PTDC/BIA-MIC/28271/2017//Fundação para a Ciência e a Tecnologia/ ; R01AI146065-01A1//National Institute of Allergy and Infectious Diseases/ ; }, abstract = {Bacterial vaginosis (BV) is associated with a highly structured polymicrobial biofilm on the vaginal epithelium where Gardnerella species presumably play a pivotal role. Gardnerella vaginalis, Atopobium vaginae, and Prevotella bivia are vaginal pathogens detected during the early stages of incident BV. Herein, we aimed to analyze the impact of A. vaginae and P. bivia on a pre-established G. vaginalis biofilm using a novel in vitro triple-species biofilm model. Total biofilm biomass was determined by the crystal violet method. We also discriminated the bacterial populations in the biofilm and in its planktonic fraction by using PNA FISH. We further analyzed the influence of A. vaginae and P. bivia on the expression of key virulence genes of G. vaginalis by quantitative PCR. In our tested conditions, A. vaginae and P. bivia were able to incorporate into pre-established G. vaginalis biofilms but did not induce an increase in total biofilm biomass, when compared with 48-h G. vaginalis biofilms. However, they were able to significantly influence the expression of HMPREF0424_0821, a gene suggested to be associated with biofilm maintenance in G. vaginalis. This study suggests that microbial relationships between co-infecting bacteria can deeply affect the G. vaginalis biofilm, a crucial marker of BV.}, } @article {pmid33672633, year = {2021}, author = {Feldman, M and Sionov, RV and Mechoulam, R and Steinberg, D}, title = {Anti-Biofilm Activity of Cannabidiol against Candida albicans.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33672633}, issn = {2076-2607}, abstract = {Candida albicans is a common fungal pathogen in humans. Biofilm formation is an important virulence factor of C. albicans infections. We investigated the ability of the plant-derived cannabidiol (CBD) to inhibit the formation and removal of fungal biofilms. Further, we evaluated its mode of action. Our findings demonstrate that CBD exerts pronounced time-dependent inhibitory effects on biofilm formation as well as disruption of mature biofilm at a concentration range below minimal inhibitory and fungicidal concentrations. CBD acts at several levels. It modifies the architecture of fungal biofilm by reducing its thickness and exopolysaccharide (EPS) production accompanied by downregulation of genes involved in EPS synthesis. It alters the fungal morphology that correlated with upregulation of yeast-associated genes and downregulation of hyphae-specific genes. Importantly, it represses the expression of C. albicans virulence-associated genes. In addition, CBD increases ROS production, reduces the intracellular ATP levels, induces mitochondrial membrane hyperpolarization, modifies the cell wall, and increases the plasma membrane permeability. In conclusion, we propose that CBD exerts its activity towards C. albicans biofilm through a multi-target mode of action, which differs from common antimycotic agents, and thus can be explored for further development as an alternative treatment against fungal infections.}, } @article {pmid33672009, year = {2021}, author = {Ma, A and Neumann, N and Chui, L}, title = {Phenotypic and Genetic Determination of Biofilm Formation in Heat Resistant Escherichia coli Possessing the Locus of Heat Resistance.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33672009}, issn = {2076-2607}, support = {AI-BIO FSC-12-015//Alberta Innovates Bio Solutions/ ; 2013R048R//Alberta Livestock and Meat Agency/ ; }, abstract = {Despite the effectiveness of thermal inactivation processes, Escherichiacoli biofilms continue to be a persistent source of contamination in food processing environments. E. coli strains possessing the locus of heat resistance are a novel food safety threat and raises the question of whether these strains can also form biofilms. The objectives of this study were to determine biofilm formation in heat resistant E. coli isolates from clinical and environmental origins using an in-house, two-component apparatus and to characterize biofilm formation-associated genes in the isolates using whole genome sequencing. Optimal conditions for biofilm formation in each of the heat resistant isolates were determined by manipulating inoculum size, nutrient concentration, and temperature conditions. Biofilm formation in the heat resistant isolates was detected at temperatures of 24 °C and 37 °C but not at 4 °C. Furthermore, biofilm formation was observed in all environmental isolates but only one clinical isolate despite shared profiles in biofilm formation-associated genes encoded by the isolates from both sources. The circulation of heat resistant E. coli isolates with multi-stress tolerance capabilities in environments related to food processing signify that such strains may be a serious food safety and public health risk.}, } @article {pmid33671537, year = {2021}, author = {Cuenca, M and Sánchez, MC and Diz, P and Martínez-Lamas, L and Álvarez, M and Limeres, J and Sanz, M and Herrera, D}, title = {In Vitro Anti-Biofilm and Antibacterial Properties of Streptococcus downii sp. nov.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33671537}, issn = {2076-2607}, support = {IN855A//Xunta de Galicia under Ignicia Programme, Axencia Galega de Innovación/ ; -//Extraordinary Chair of DENTAID, University Complutense of Madrid, Spain./ ; }, abstract = {The aim of this study was to evaluate the potential anti-biofilm and antibacterial activities of Streptococcus downii sp. nov. To test anti-biofilm properties, Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans were grown in a biofilm model in the presence or not of S. downii sp. nov. for up to 120 h. For the potential antibacterial activity, 24 h-biofilms were exposed to S. downii sp. nov for 24 and 48 h. Biofilms structures and bacterial viability were studied by microscopy, and the effect in bacterial load by quantitative polymerase chain reaction. A generalized linear model was constructed, and results were considered as statistically significant at p < 0.05. The presence of S. downii sp. nov. during biofilm development did not affect the structure of the community, but an anti-biofilm effect against S. mutans was observed (p < 0.001, after 96 and 120 h). For antibacterial activity, after 24 h of exposure to S. downii sp. nov., counts of S. mutans (p = 0.019) and A. actinomycetemcomitans (p = 0.020) were significantly reduced in well-structured biofilms. Although moderate, anti-biofilm and antibacterial activities of S. downii sp. nov. against oral bacteria, including some periodontal pathogens, were demonstrated in an in vitro biofilm model.}, } @article {pmid33671457, year = {2021}, author = {Velgosova, O and Mudra, E and Vojtko, M}, title = {Preparing, Characterization and Anti-Biofilm Activity of Polymer Fibers Doped by Green Synthesized AgNPs.}, journal = {Polymers}, volume = {13}, number = {4}, pages = {}, pmid = {33671457}, issn = {2073-4360}, abstract = {The aim of the work was to prepare polymer matrix composite (PMC) microfibers doped by green synthesized silver nanoparticles (AgNPs). The incorporation of AgNP into the polymer matrix can provide toxic properties to the polymer. Polyvinyl alcohol (PVA) was used as a matrix. AgNPs were synthesized by the green method, where the leaf extract of Rosmarinus officinalis (R. officinalis) was used as a reduction and capping agent. PVA-AgNPs composites were prepared in two ways: the ex situ method (pre-prepared globular AgNPs with a mean diameter of 20 nm were added into polymer matrix) and the in situ method (AgNPs were synthesized in the process of polymer composite preparation; in situ synthesized nanoparticles were a mix of different shapes with a mean diameter of ~100 nm). FTIR (Infrared spectroscopy with Fourier Transformation), UV-vis (Ultraviolet-visible spectroscopy), TEM (Transmission Electron Microscope), EDX (Energy-dispersive X-ray spectroscopy), and SEM (Scanning Electron Microscope) techniques were used for the analysis of nanoparticles and prepared PMCs. Thin layers and microfibers of in situ and ex situ PMCs were prepared. The presence of AgNPs clusters was evident in both PMC thin layers. After electrospinning, the chains of nanoparticles were observed inside the fibers. The distribution of nanoparticles was improved by increasing the AgNPs volume fraction (from 5 vol.% to 20 vol.%). Toxic and antibiofilm activity of AgNPs colloid, pure PVA, and PVA-AgNPs composites against the one-cell green algae Parachlorella kessleri (P. kessleri) was analyzed. AgNPs colloid, as well as PVA-AgNPs composites, showed good toxic and antibiofilm activity, and pure PVA shows no toxic/antibiofilm activity.}, } @article {pmid33670887, year = {2021}, author = {Bogiel, T and Depka, D and Rzepka, M and Kwiecińska-Piróg, J and Gospodarek-Komkowska, E}, title = {Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {3}, pages = {}, pmid = {33670887}, issn = {2079-6382}, support = {PDB WF 839//Uniwersytet Mikolaja Kopernika w Toruniu/ ; }, abstract = {Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes' prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin.}, } @article {pmid33670726, year = {2021}, author = {Ji, J and Yang, H}, title = {In Vitro Effects of Lactobacillus plantarum LN66 and Antibiotics Used Alone or in Combination on Helicobacter pylori Mature Biofilm.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33670726}, issn = {2076-2607}, support = {HUCXY-2016-010//Shanghai Industry-University Joint Research Program/ ; }, abstract = {Helicobacter pylori is a gastrointestinal pathogen with high prevalence that harms human health. Studies have shown that H. pylori can form antibiotic-tolerant biofilms, which may interfere with the efficacy of clinical antibiotic therapy. Probiotics can antagonize planktonic and biofilm pathogen cells and thus may play an auxiliary role in H. pylori antibiotic therapy. However, the effects of different probiotic strains and antibiotic combinations on H. pylori biofilms need to be further investigated. We determined the cell viability of H. pylori mature biofilms after treatment with Lactobacillus plantarum LN66 cell-free supernatant (CFS), clarithromycin (CLR), and levofloxacin (LVX) alone or in combination by the XTT method. Biofilm cells were observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Subsequently, protein and polysaccharide concentrations in biofilm extracellular polymeric substances (EPSs) were quantitatively detected by the Bradford method and the phenol-sulfate method. The results showed that LN66 CFS had an eradication effect on mature H. pylori biofilm. When used in combination with CLR, LN66 CFS significantly attenuated the eradication effect of CLR on biofilms; in contrast, when used in combination with LVX, LN66 CFS enhanced the disrupting effect of LVX. We speculate that the different effects of CFS and antibiotic combinations on biofilms may be related to changes in the content of proteins and polysaccharides in EPS and that the combination of CFS and CLR might promote the secretion of EPS, while the combination of CFS and LVX might have the opposite effect. Accordingly, we suggest that supplementation with L. plantarum LN66 may provide additional help when therapy involving LVX is used for clinical H. pylori biofilm eradication, whereas it may impair CLR efficacy when therapy involving CLR is used.}, } @article {pmid33670010, year = {2021}, author = {Heredia-Ponce, Z and de Vicente, A and Cazorla, FM and Gutiérrez-Barranquero, JA}, title = {Beyond the Wall: Exopolysaccharides in the Biofilm Lifestyle of Pathogenic and Beneficial Plant-Associated Pseudomonas.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33670010}, issn = {2076-2607}, abstract = {The formation of biofilms results from a multicellular mode of growth, in which bacteria remain enwrapped by an extracellular matrix of their own production. Many different bacteria form biofilms, but among the most studied species are those that belong to the Pseudomonas genus due to the metabolic versatility, ubiquity, and ecological significance of members of this group of microorganisms. Within the Pseudomonas genus, biofilm studies have mainly focused on the opportunistic human pathogen Pseudomonas aeruginosa due to its clinical importance. The extracellular matrix of P. aeruginosa is mainly composed of exopolysaccharides, which have been shown to be important for the biofilm architecture and pathogenic features of this bacterium. Notably, some of the exopolysaccharides recurrently used by P. aeruginosa during biofilm formation, such as the alginate and polysaccharide synthesis loci (Psl) polysaccharides, are also used by pathogenic and beneficial plant-associated Pseudomonas during their interaction with plants. Interestingly, their functions are multifaceted and seem to be highly dependent on the bacterial lifestyle and genetic context of production. This paper reviews the functions and significance of the exopolysaccharides produced by plant-associated Pseudomonas, particularly the alginate, Psl, and cellulose polysaccharides, focusing on their equivalents produced in P. aeruginosa within the context of pathogenic and beneficial interactions.}, } @article {pmid33669562, year = {2021}, author = {Sánchez, MC and Alonso-Español, A and Ribeiro-Vidal, H and Alonso, B and Herrera, D and Sanz, M}, title = {Relevance of Biofilm Models in Periodontal Research: From Static to Dynamic Systems.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33669562}, issn = {2076-2607}, abstract = {Microbial biofilm modeling has improved in sophistication and scope, although only a limited number of standardized protocols are available. This review presents an example of a biofilm model, along with its evolution and application in studying periodontal and peri-implant diseases. In 2011, the ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) research group at the University Complutense of Madrid developed an in vitro biofilm static model using representative bacteria from the subgingival microbiota, demonstrating a pattern of bacterial colonization and maturation similar to in vivo subgingival biofilms. When the model and its methodology were standardized, the ETEP research group employed the validated in vitro biofilm model for testing in different applications. The evolution of this model is described in this manuscript, from the mere observation of biofilm growth and maturation on static models on hydroxyapatite or titanium discs, to the evaluation of the impact of dental implant surface composition and micro-structure using the dynamic biofilm model. This evolution was based on reproducing the ideal microenvironmental conditions for bacterial growth within a bioreactor and reaching the target surfaces using the fluid dynamics mimicking the salivary flow. The development of this relevant biofilm model has become a powerful tool to study the essential processes that regulate the formation and maturation of these important microbial communities, as well as their behavior when exposed to different antimicrobial compounds.}, } @article {pmid33669279, year = {2021}, author = {Galdiero, E and Salvatore, MM and Maione, A and Carraturo, F and Galdiero, S and Falanga, A and Andolfi, A and Salvatore, F and Guida, M}, title = {Impact of the Peptide WMR-K on Dual-Species Biofilm Candida albicans/Klebsiella pneumoniae and on the Untargeted Metabolomic Profile.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33669279}, issn = {2076-0817}, abstract = {In recent years, the scientific community has focused on the development of new antibiotics to address the difficulties linked to biofilm-forming microorganisms and drug-resistant infections. In this respect, synthetic antimicrobial peptides (AMPs) are particularly regarded for their therapeutic potential against a broad spectrum of pathogens. In this work, the antimicrobial and antibiofilm activities of the peptide WMR-K towards single and dual species cultures of Candida albicans and Klebsiella pneumoniae were investigated. We found minimum inhibitory concentration (MIC) values for WMR-K of 10 µM for K. pneumoniae and of 200 µM for C. albicans. Furthermore, sub-MIC concentrations of peptide showed an in vitro inhibition of biofilm formation of mono and polymicrobial systems and also a good biofilm eradication even if higher concentrations of it are needed. In order to provide additional evidence for the effect of the examined peptide, a study of changes in extracellular metabolites excreted and/or uptaken from the culture medium (metabolomic footprinting) in the poly-microbial association of C. albicans and K. pneumoniae in presence and absence of WMR-K was performed. Comparing to the untreated dual species biofilm culture, the metabolomic profile of the WMR-K treated culture appears significantly altered. The differentially expressed compounds are mainly related to the primary metabolic pathways, including amino acids, trehalose, pyruvic acid, glycerol and vitamin B6.}, } @article {pmid33666753, year = {2021}, author = {Perera, M and Chinthaka, SDM and Wijayarathna, CD and Wijesundera, S and Seneviratne, G and Jayasena, S}, title = {Reduction of lag in crude oil degradation by Aspergillus when it is in synergy with Bacillus in biofilm mode.}, journal = {Bioprocess and biosystems engineering}, volume = {44}, number = {7}, pages = {1501-1510}, pmid = {33666753}, issn = {1615-7605}, support = {AP/3/2/2014/RG/12//University of Colombo/ ; }, mesh = {Aspergillus/*metabolism ; Bacillus/*metabolism ; Biodegradation, Environmental ; Biodiversity ; *Biofilms ; Biotechnology/*methods ; Gas Chromatography-Mass Spectrometry ; Hydrocarbons/chemistry ; Industrial Microbiology/*methods ; Nutrients ; Petroleum/*metabolism ; Temperature ; }, abstract = {A major hindrance to the effective use of fungi in bioremediation is their inherent slow growth. Despite this, Aspergillus spp. may be used effectively. Our experiments demonstrate that bacteria, although inefficient in hydrocarbon degradation, may be effectively used in a consortium to overcome the lag in fungal utilization of petroleum hydrocarbons. Crude petroleum oil (160 mg; at 8 g/L) in minimal medium was inoculated with a previously isolated biofilm-forming consortium (Aspergillus sp. MM1 and Bacillus sp. MM1) as well as monocultures of each organism and incubated at 30 ℃ under static conditions. Residual oil was analyzed by GC-MS. Crude oil utilization of Aspergillus-Bacillus biofilm was 24 ± 1.4% in 3 days, increased to 66 ± 7% by day 5 and reached 99 ± 0.2% in 7 days. Aspergillus sp. MM1 monoculture degraded only 14 ± 6% in 5 days. However, at the end of 7 days, it was able to utilize 98 ± 2%. Bacillus sp. MM1 monoculture utilized 20 ± 4% in 7 days. This study indicates that there is a reduction of the fungal lag in bioremediation when it is in association with the bacterium. Although in monoculture, Bacillus sp. MM1 is inefficient in crude oil degradation, it synergistically enhances the initial rate of crude petroleum oil degradation of the fungus in the consortium. The rapid initial removal of as much crude oil as possible from contaminated sites is vital to minimize detrimental impacts on biodiversity.}, } @article {pmid33666383, year = {2021}, author = {Furrer, C and Bättig, R and Votta, I and Bastendorf, KD and Schmidlin, PR}, title = {[Patient acceptance of «Guided Biofilm Therapy»].}, journal = {Swiss dental journal}, volume = {131}, number = {3}, pages = {229-234}, pmid = {33666383}, issn = {2296-6498}, mesh = {Biofilms ; Dental Care ; *Dental Plaque ; Humans ; }, abstract = {«Guided Biofilm Therapy» (GBT) represents a systematic, risk and demand-oriented prophylaxis and treatment concept. A significant difference to conventional methods is - above all - the reduced, tissue-friendly and targeted use of ultrasound and hand instruments. The biofilm is consistently shown with suitable color solutions, the oral hygiene instruction and professional tooth cleaning is optimized. The use of suitable powders guarantees a tissue-conserving and targeted removal of biofilm. While individual treatments, techniques and materials have already been well investigated and described, little data is available on patient acceptance. The aim of the present study was to gain an impression of the acceptance of this method in comparison to the conservative-classical recall care mainly based on hand and ultrasound devices in a survey of 100 consecutive patients from the clinic's internal recall system. The overall results were very positive. The powder jet device showed the best acceptance. The aspect fear before/during the recall session was also interesting: At a low level (10%), an additional reduction to 4% occurred, since hand instruments were probably used much less and only very specifically. mConclusion: The use of plaque elevators makes the work in the recall session more efficient, more effective and guarantees ma higher quality control, which is also highly appreciated by patients.}, } @article {pmid33666152, year = {2021}, author = {Taylor, A and Fuzi, J and Sideris, A and Banks, C and Havas, TE}, title = {Non-steroid, non-antibiotic anti-biofilm therapy for the treatment of chronic rhinosinusitis: a systematic review.}, journal = {The Journal of laryngology and otology}, volume = {135}, number = {3}, pages = {196-205}, doi = {10.1017/S0022215121000542}, pmid = {33666152}, issn = {1748-5460}, mesh = {Administration, Topical ; Adult ; Anti-Infective Agents, Local/*therapeutic use ; Biofilms/*drug effects ; Chronic Disease ; Clinical Trials as Topic ; Female ; Humans ; Male ; Middle Aged ; Nasal Cavity/microbiology ; Patient Reported Outcome Measures ; Rhinitis/*drug therapy/microbiology ; Sinusitis/*drug therapy/microbiology ; Treatment Outcome ; }, abstract = {OBJECTIVE: Chronic rhinosinusitis patients with biofilms cultured from their sinonasal cavity have greater symptom burden and risk of recalcitrant disease. A number of non-antibiotic, 'anti-biofilm' treatments exist which show anti-biofilm properties in preclinical studies. There is little evidence evaluating their impact on clinical symptom scores in chronic rhinosinusitis.

METHOD: A systematic review was performed to assess the literature regarding the efficacy of non-steroid, non-antibiotic, anti-biofilm specific topical therapies in the treatment of chronic rhinosinusitis. The primary outcome assessed was change in validated patient reported outcome measures before and after anti-biofilm treatment.

RESULTS: Thirteen studies assessing the effect of anti-biofilm therapies in chronic rhinosinusitis through validated patient-reported outcome measures were included. Seven different anti-biofilm specific therapies for chronic rhinosinusitis were identified. None of the seven anti-biofilm therapies was identified as being confidently efficacious beyond placebo. Only one therapy (intranasal xylitol) showed a statistically significant reduction in symptom scores compared with placebo in more than one trial.

CONCLUSION: Robust evidence supporting the use of various anti-biofilm therapies in chronic rhinosinusitis is lacking. Further high quality, human, in vivo trials studying the effect of anti-biofilm therapies in chronic rhinosinusitis are needed to address the deficiencies of the current evidence base.}, } @article {pmid33665217, year = {2021}, author = {de Sá, MCA and da Silva, WM and Rodrigues, CCS and Rezende, CP and Marchioro, SB and Rocha Filho, JTR and Sousa, TJ and de Oliveira, HP and da Costa, MM and Figueiredo, HCP and Portela, RD and Castro, TLP and Azevedo, V and Seyffert, N and Meyer, R}, title = {Comparative Proteomic Analyses Between Biofilm-Forming and Non-biofilm-Forming Strains of Corynebacterium pseudotuberculosis Isolated From Goats.}, journal = {Frontiers in veterinary science}, volume = {8}, number = {}, pages = {614011}, pmid = {33665217}, issn = {2297-1769}, abstract = {Caseous lymphadenitis (CLA) is a chronic disease that affects small ruminants and causes economic losses in the associated breeding system. The causative agent of CLA is Corynebacterium pseudotuberculosis, a Gram-positive bacterium that exhibits tropism for external and internal lymph nodes and induces abscess formation in the host. Bacterial communities often produce a biofilm matrix that serves various functions, including protection against hostile environmental conditions, antibiotics, and the host immune response. Although biofilm formation has been reported for C. pseudotuberculosis, not all strains demonstrate this property in culture. In this work, we report the first comparative proteomic analysis of one biofilm-forming (CAPJ4) and one biofilm-non-forming strain (CAP3W) of C. pseudotuberculosis isolated from goats. Bacterial whole cell protein extracts were obtained for mass spectrometry analyses. Using LC-MS/MS, our studies reveal three and four proteins exclusively found in the CAPJ4 and CAP3W proteome, respectively. In addition, label-free quantitative analysis identified 40 proteins showing at-least 2-fold higher values in CAPJ4 compared CAP3W proteome Notably, CAPJ4 differentially synthesized the penicillin-binding protein, which participates in the formation of peptidoglycans. CAPJ4 also exhibited upregulation of N-acetylmuramoyl-L-alanine amidase and galactose-1-phosphate uridylyltransferase, which are involved in biofilm formation and exopolysaccharide biosynthesis. Here, we demonstrate that biofilm formation in C. pseudotuberculosis is likely associated with specific proteins, some of which were previously shown to be associated with virulence and biofilm formation in other organisms. Our findings may drive studies related to the bacterial mechanisms involved in the biofilm formation, in addition to providing targets for the treatment of CLA.}, } @article {pmid33664521, year = {2021}, author = {Li, ZR and Sun, J and Du, Y and Pan, A and Zeng, L and Maboudian, R and Burne, RA and Qian, PY and Zhang, W}, title = {Mutanofactin promotes adhesion and biofilm formation of cariogenic Streptococcus mutans.}, journal = {Nature chemical biology}, volume = {17}, number = {5}, pages = {576-584}, pmid = {33664521}, issn = {1552-4469}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Biological Factors/*biosynthesis/isolation & purification/pharmacology ; Computational Biology/methods ; DNA/genetics/metabolism ; Dental Caries/microbiology/pathology ; Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Humans ; Hydrophobic and Hydrophilic Interactions ; Multigene Family ; Peptide Biosynthesis, Nucleic Acid-Independent ; Protein Binding ; Secondary Metabolism/*genetics ; Streptococcus mutans/genetics/growth & development/*metabolism/pathogenicity ; }, abstract = {Cariogenic Streptococcus mutans is known as a predominant etiological agent of dental caries due to its exceptional capacity to form biofilms. From strains of S. mutans isolated from dental plaque, we discovered, in the present study, a polyketide/nonribosomal peptide biosynthetic gene cluster, muf, which directly correlates with a strong biofilm-forming capability. We then identified the muf-associated bioactive product, mutanofactin-697, which contains a new molecular scaffold, along with its biosynthetic logic. Further mode-of-action studies revealed that mutanofactin-697 binds to S. mutans cells and also extracellular DNA, increases bacterial hydrophobicity, and promotes bacterial adhesion and subsequent biofilm formation. Our findings provided an example of a microbial secondary metabolite promoting biofilm formation via a physicochemical approach, highlighting the importance of secondary metabolism in mediating critical processes related to the development of dental caries.}, } @article {pmid33664312, year = {2021}, author = {Sultan, AR and Lattwein, KR and Lemmens-den Toom, NA and Snijders, SV and Kooiman, K and Verbon, A and van Wamel, WJB}, title = {Paracetamol modulates biofilm formation in Staphylococcus aureus clonal complex 8 strains.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {5114}, pmid = {33664312}, issn = {2045-2322}, mesh = {Acetaminophen/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Humans ; Microbial Viability/drug effects ; Staphylococcal Infections/*drug therapy/microbiology/pathology ; Staphylococcus aureus/*drug effects/pathogenicity ; }, abstract = {Staphylococcus aureus biofilms are a major problem in modern healthcare due to their resistance to immune system defenses and antibiotic treatments. Certain analgesic agents are able to modulate S. aureus biofilm formation, but currently no evidence exists if paracetamol, often combined with antibiotic treatment, also has this effect. Therefore, we aimed to investigate if paracetamol can modulate S. aureus biofilm formation. Considering that certain regulatory pathways for biofilm formation and virulence factor production by S. aureus are linked, we further investigated the effect of paracetamol on immune modulator production. The in vitro biofilm mass of 21 S. aureus strains from 9 genetic backgrounds was measured in the presence of paracetamol. Based on biofilm mass quantity, we further investigated paracetamol-induced biofilm alterations using a bacterial viability assay combined with N-Acetylglucosamine staining. Isothermal microcalorimetry was used to monitor the effect of paracetamol on bacterial metabolism within biofilms and green fluorescent protein (GFP) promoter fusion technology for transcription of staphylococcal complement inhibitor (SCIN). Clinically relevant concentrations of paracetamol enhanced biofilm formation particularly among strains belonging to clonal complex 8 (CC8), but had minimal effect on S. aureus planktonic growth. The increase of biofilm mass can be attributed to the marked increase of N-Acetylglucosamine containing components of the extracellular matrix, presumably polysaccharide intercellular adhesion. Biofilms of RN6390A (CC8) showed a significant increase in the immune modulator SCIN transcription during co-incubation with low concentrations of paracetamol. Our data indicate that paracetamol can enhance biofilm formation. The clinical relevance needs to be further investigated.}, } @article {pmid33663287, year = {2022}, author = {Kim, U and Kim, JH and Oh, SW}, title = {Review of multi-species biofilm formation from foodborne pathogens: multi-species biofilms and removal methodology.}, journal = {Critical reviews in food science and nutrition}, volume = {62}, number = {21}, pages = {5783-5793}, doi = {10.1080/10408398.2021.1892585}, pmid = {33663287}, issn = {1549-7852}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; *Biofilms ; Food-Processing Industry ; Quorum Sensing ; }, abstract = {Multi-species biofilms are ubiquitous worldwide and are a concern in the food industry. Multi-species biofilms have a higher resistance to antimicrobial therapies than mono-species biofilms. In addition, multi-species biofilms can cause severe foodborne diseases. To remove multi-species biofilms, controlling the formation process of extracellular polymeric substances (EPS) and quorum sensing (QS) effects is essential. EPS disruption, inhibition of QS, and disinfection have been utilized to remove multi-species biofilms. This review presents information on the formation and novel removal methods for multi-species biofilms.}, } @article {pmid33662064, year = {2021}, author = {Nishitani Shibasaki, PA and Cavalli, V and Oliveira, MC and Barbosa, JP and Gomes Boriollo, MF and Marcondes Martins, LR}, title = {Influence Of Surface Treatment On The Physical Properties And Biofilm Formation Of Zirconia-Reinforced Lithium Silicate Ceramics: In Vitro Trial.}, journal = {The International journal of prosthodontics}, volume = {}, number = {}, pages = {}, doi = {10.11607/ijp.7192}, pmid = {33662064}, issn = {1942-4426}, abstract = {PURPOSE: To evaluate the performance of fully (Celtra Duo, Dentsply Sirona) and partially (VITA Suprinity, VITA) crystallized zirconia-reinforced lithium silicate and partially sintered lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) glass-ceramics submitted to polishing, glazing, or no surface treatment after aging.

MATERIALS AND METHODS: Specimens of each glass-ceramic were subjected to polishing with rubber cups (POL), glazing (GL), or control (C; no treatment) and afterwards aged with 18,000 thermal cycles (5°C to 55°C). The average roughness (Ra), 2D and 3D morphology, contact angle, multispecies biofilm formation (Streptococcus mutans and Candida albicans), and mechanical strength were evaluated by atomic force microscopy (AFM, n = 5), sessile-drop goniometry (n = 5), spectrophotometry (n = 5), and flexural strength test (n = 10), respectively. Data were analyzed using two-way analysis of variance and Tukey test (α = 5%).

RESULTS: POL promoted lower Ra than glazing, and Celtra Duo presented higher Ra than IPS e.max CAD (P < .05). Surfaces without polishing promoted higher Ra than the POL group (P < .001), greater contact angle (P < .001), and significant morphologic changes, regardless of the glass-ceramic. Irrespective of the treatment, the contact angle was higher in Celtra Duo, and regardless of the material, there was higher biofilm formation and lower flexural strength of unpolished compared to POL or GL ceramics.

CONCLUSION: Polishing with rubber cups promoted lower roughness and minor morphologic surface alterations, but biofilm formation and flexural strength were similar to the glazed surface. In general, Celtra Duo and VITA Suprinity showed similar behavior to IPS e.max CAD, which makes zirconia-reinforced lithium silicate glass-ceramics a good option for indirect restorations.}, } @article {pmid33660315, year = {2022}, author = {Matthes de Freitas Pontes, K and Fontenelle, ISO and Nascimento, CD and Oliveira, VC and Albuquerque Garcia, B and Silva, PGB and Henrique, LS and de Souza, KM and Pontes, CB}, title = {Clinical study of the biofilm of implant-supported complete dentures in healthy patients.}, journal = {Gerodontology}, volume = {39}, number = {2}, pages = {148-160}, doi = {10.1111/ger.12547}, pmid = {33660315}, issn = {1741-2358}, mesh = {Aged ; Bacteria ; Biofilms ; DNA ; *Dental Implants ; Dental Prosthesis, Implant-Supported ; Denture, Complete ; Humans ; }, abstract = {OBJECTIVE: The purpose of this study was to quantify the area covered by biofilm and identify bacteria and yeasts present in mandibular acrylic resin full-arch implant-supported fixed prostheses.

BACKGROUND: Biofilm control of implant-supported fixed prosthesis is hampered by their design, and it can cause oral and systemic problems, mainly in immunocompromised patients like the elder. Knowledge about microbiota reinforces the awareness about the need for periodic professional cleaning maintenance.

MATERIALS AND METHODS: Twenty prostheses were unscrewed, washed in 0.89% sodium chloride, stained with eosin 1% and photographed. The area covered by biofilm was digitally delimited and quantified. Biofilm samples were collected, diluted up to 1:10[7] , seeded in chromogenic agar media and incubated for 48 hours, at 37°C, for counting of colony-forming units (CFU/mL). DNA hybridization was performed to complement the identification and quantification of microorganisms. Data were analyzed using Mann-Whitney test, Spearman correlation and Fisher's exact test (α = .05).

RESULTS: An average of 62% of the gingival surface of the prostheses was covered by biofilm. Enterococcus spp. (5.82 ± 1.38 log10 CFU/mL) and Staphylococcus aureus (5.75 ± 2.02 log10 CFU/mL) showed higher prevalence in cultures. Patients with five implants had less biofilm compared to those with four implants (P = .031) but had higher Escherichia coli counts (P = .039). In DNA hybridization, Streptococcus pneumoniae, Veillonella parvula and Fusobacterium nucleatum presented higher quantification and were present in all the samples; patients over 65 years old contained more Candida tropicalis (P = .049); prostheses on five implants presented lower quantification for several species.

CONCLUSION: Biofilm was present on all prostheses, containing potentially pathogenic microorganisms. The number of implants may play a role in quantification of biofilm and in microorganism counts.}, } @article {pmid33660220, year = {2021}, author = {Hazarika, P and Chattopadhyay, I and Umpo, M and Choudhury, Y and Sharma, I}, title = {Phylogeny, Biofilm Production, and Antimicrobial Properties of Fecal Microbial Communities of Adi Tribes of Arunachal Pradesh, India.}, journal = {Applied biochemistry and biotechnology}, volume = {193}, number = {6}, pages = {1675-1687}, pmid = {33660220}, issn = {1559-0291}, support = {RBMCH/NER/10/2019-20//Indian Council of Medical Research/ ; }, mesh = {Anti-Infective Agents/*metabolism ; Bacteria/classification/*metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Feces/*microbiology ; Gastrointestinal Microbiome/*physiology ; Humans ; India/ethnology ; *Phylogeny ; }, abstract = {The fecal flora consists of trillions of bacteria influencing human health and several host factors. Such population-based fecal flora studies are critical to uplift the health status of ethnic tribes from Arunachal Pradesh. This study aimed to analyze the ethnic tribe's biofilm producing antibiotic resistant bacteria and their phyllogenetic analysis in 15 stool samples collected from Adi tribes of Arunachal Pradesh. Of the analyzed samples, 42.85% were Escherichia, 20% lactic acid bacteria, 20% Salmonella, and 17.14% Enterococcus. Escherichia coli, lactic acid bacteria, and Enterococcus sp. emerged as strong biofilm producers; however, Salmonella declined to exhibit characters for a strong biofilm producer. Tetracycline resistance dominated in all the gut bacterial profiles. The 16SrRNA amplified PCR product was used for sequencing, and a phylogenetic tree was constructed exhibiting the relationship between the isolates. The test sequences were compared with the non-redundant Gene bank collection of the database with the Basic Local Alignment Search Tool.}, } @article {pmid33660005, year = {2022}, author = {Gould, FG and Carey, MP and Plummer, EL and Murray, GL and Danielewski, JA and Tabrizi, SN and Garland, SM}, title = {Bacterial biofilm formation on vaginal ring pessaries used for pelvic organ prolapse.}, journal = {International urogynecology journal}, volume = {33}, number = {2}, pages = {287-295}, pmid = {33660005}, issn = {1433-3023}, support = {Urogynaecology Special Purpose Fund//The Royal Women's Hospital, Melbourne, Australia/ ; }, mesh = {Biofilms ; *Contraceptive Devices, Female ; Cross-Sectional Studies ; Female ; Humans ; Lactobacillus ; *Pelvic Organ Prolapse/therapy ; Pessaries ; RNA, Ribosomal, 16S ; }, abstract = {INTRODUCTION AND HYPOTHESIS: The objective of this study was to characterize the bacterial biofilm on vaginal ring pessaries used to treat pelvic organ prolapse and investigate the relationship between biofilm phenotype and patient symptoms and clinical signs that are suggestive of inflammation.

METHODS: This was a cross-sectional observational study of 40 women wearing a ring-shaped pessary continuously for at least 12 weeks. Participants underwent a clinical examination, and the pessary was removed. Clinical signs were recorded. A swab from the pessary surface and a high vaginal swab were collected from each woman. Participants completed a questionnaire on symptoms. Pessary biofilm presence and phenotype were determined by scanning electron microscopy (SEM). Vaginal and pessary bacterial composition was determined by 16S rRNA gene sequencing. The relationship between biofilm phenotype and symptoms and clinical signs was assessed using logistic regression.

RESULTS: SEM confirmed biofilm formation on all 40 pessaries. Microbiota data were available for 25 pessary swabs. The pessary biofilm microbiota was composed of bacteria typically found in the vagina and was categorized into Lactobacillus-dominated (n = 10/25 pessaries, 40%) communities and Lactobacillus-deficient communities with high relative abundance of anaerobic/facultative anaerobes (n = 15/25 pessaries, 60%). While increasing age was associated with presence of a Lactobacillus-deficient pessary biofilm (odds ratio = 3.60, 95% CI [1.16-11.22], p = 0.04), no associations between biofilm microbiota composition and symptoms or clinical signs were observed.

CONCLUSIONS: Lactobacillus-deficient biofilms commonly form on pessaries following long-term use. However, the contribution of biofilm phenotype to symptoms and clinical signs remains to be determined.}, } @article {pmid33658521, year = {2021}, author = {Tomlinson, KL and Lung, TWF and Dach, F and Annavajhala, MK and Gabryszewski, SJ and Groves, RA and Drikic, M and Francoeur, NJ and Sridhar, SH and Smith, ML and Khanal, S and Britto, CJ and Sebra, R and Lewis, I and Uhlemann, AC and Kahl, BC and Prince, AS and Riquelme, SA}, title = {Staphylococcus aureus induces an itaconate-dominated immunometabolic response that drives biofilm formation.}, journal = {Nature communications}, volume = {12}, number = {1}, pages = {1399}, pmid = {33658521}, issn = {2041-1723}, support = {R35 HL135800/HL/NHLBI NIH HHS/United States ; UL1 TR001863/TR/NCATS NIH HHS/United States ; }, mesh = {Adult ; Animals ; Biofilms/growth & development ; Bronchoalveolar Lavage Fluid ; Carbohydrate Metabolism ; Cystic Fibrosis/microbiology ; Gene Expression Regulation, Bacterial ; Glycolysis/drug effects/physiology ; Host-Pathogen Interactions/immunology/*physiology ; Humans ; Hydro-Lyases/metabolism ; Mice, Inbred C57BL ; Pseudomonas Infections/immunology/metabolism ; Reactive Oxygen Species/metabolism ; Sputum/microbiology ; Staphylococcal Infections/*immunology/metabolism ; Staphylococcus aureus/drug effects/isolation & purification/*pathogenicity/*physiology ; Stress, Physiological ; Succinates/*metabolism/pharmacology ; Succinic Acid/metabolism ; Young Adult ; }, abstract = {Staphylococcus aureus is a prominent human pathogen that readily adapts to host immune defenses. Here, we show that, in contrast to Gram-negative pathogens, S. aureus induces a distinct airway immunometabolic response dominated by the release of the electrophilic metabolite, itaconate. The itaconate synthetic enzyme, IRG1, is activated by host mitochondrial stress, which is induced by staphylococcal glycolysis. Itaconate inhibits S. aureus glycolysis and selects for strains that re-direct carbon flux to fuel extracellular polysaccharide (EPS) synthesis and biofilm formation. Itaconate-adapted strains, as illustrated by S. aureus isolates from chronic airway infection, exhibit decreased glycolytic activity, high EPS production, and proficient biofilm formation even before itaconate stimulation. S. aureus thus adapts to the itaconate-dominated immunometabolic response by producing biofilms, which are associated with chronic infection of the human airway.}, } @article {pmid33657813, year = {2021}, author = {Kaizerman-Kane, D and Hadar, M and Joseph, R and Logviniuk, D and Zafrani, Y and Fridman, M and Cohen, Y}, title = {Design Guidelines for Cationic Pillar[n]arenes that Prevent Biofilm Formation by Gram-Positive Pathogens.}, journal = {ACS infectious diseases}, volume = {7}, number = {3}, pages = {579-585}, pmid = {33657813}, issn = {2373-8227}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; Cations ; Gram-Positive Bacteria ; Humans ; Structure-Activity Relationship ; }, abstract = {Bacterial biofilms are a major threat to human health, causing persistent infections that lead to millions of fatalities worldwide every year. Biofilms also cause billions of dollars of damage annually by interfering with industrial processes. Recently, cationic pillararenes were found to be potent inhibitors of biofilm formation in Gram-positive bacteria. To identify the structural features of pillararenes that result in antibiofilm activity, we evaluated the activity of 16 cationic pillar[5]arene derivatives including that of the first cationic water-soluble pillar[5]arene-based rotaxane. Twelve of the derivatives were potent inhibitors of biofilm formation by Gram-positive pathogens. Structure activity analyses of our pillararene derivatives indicated that positively charged head groups are critical for the observed antibiofilm activity. Although certain changes in the lipophilicity of the substituents on the positively charged head groups are tolerated, dramatic elevation in the hydrophobicity of the substituents or an increase in steric bulk on these positive charges abolishes the antibiofilm activity. An increase in the overall positive charge from 10 to 20 did not affect the activity significantly, but pillararenes with 5 positive charges and 5 long alkyl chains had reduced activity. Surprisingly, the cavity of the pillar[n]arene is not essential for the observed activity, although the macrocyclic structure of the pillar[n]arene core, which facilitates the clustering of the positive charges, appears important. Interestingly, the compounds found to be efficient inhibitors of biofilm formation were nonhemolytic at concentrations that are ∼100-fold of their MBIC50 (the minimal concentration of a compound at which at least 50% inhibition of biofilm formation was observed compared to untreated cells). The structure-activity relationship guidelines established here pave the way for a rational design of potent cationic pillar[n]arene-based antibiofilm agents.}, } @article {pmid33656375, year = {2021}, author = {Kaźmierczak, N and Grygorcewicz, B and Piechowicz, L}, title = {Biofilm Formation and Prevalence of Biofilm-Related Genes Among Clinical Strains of Multidrug-Resistant Staphylococcus aureus.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {7}, pages = {956-964}, doi = {10.1089/mdr.2020.0399}, pmid = {33656375}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Drug Resistance, Multiple, Bacterial/*drug effects/genetics ; Genes, Bacterial/genetics ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/genetics/*growth & development ; }, abstract = {The biofilm-forming Staphylococcus aureus strains are responsible for causing a number of diseases. With the emergence of multidrug resistance they constitute a catastrophic threat to medicine. The ability of 65 clinical strains of multidrug-resistant S. aureus (MDRSA) to form biofilm in vitro was examined in this study and analyzed in relation to SCCmec, spa type, microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), and ica genes. Results obtained from crystal violet and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays showed that all MDRSA strains tested form biofilm but, of 65 strains, only 18 strains (28%) were found to form a biofilm with high metabolic activity and a great amount of biomass. The high proportion of MDRSA isolates in our study made no significant difference for ica and MSCRAMMs genes according to biofilm-forming capacity, except for fib, icaA, and cna gene. In addition, this study demonstrated that strains carrying SCCmec type I showed a significantly decreased biofilm viability compared with the strains harboring SCCmec type II and type IV, but SCCmec type could not serve as a good predictor of biofilm formation. However, we found that significantly weaker metabolic activity was detected in the biofilm of isolates with spa type t011.}, } @article {pmid33656065, year = {2021}, author = {Feng, Y and Wang, H and Lu, HE and Yi, L and Hong, LI}, title = {Effects of ClpP protease on biofilm formation of Enterococcus faecalis.}, journal = {Journal of applied oral science : revista FOB}, volume = {29}, number = {}, pages = {e20200733}, pmid = {33656065}, issn = {1678-7765}, mesh = {*Biofilms ; Endopeptidase Clp ; *Enterococcus faecalis ; Humans ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Peptide Hydrolases ; Virulence ; }, abstract = {OBJECTIVES: Enterococcus faecalis (E. faecalis), one of the main pathogens responsible for refractory periapical periodontitis and nosocomial infections, exhibits markedly higher pathogenicity in biofilms. Studies have shown that caseinolytic protease P (ClpP) is involved in biofilm formation. However, to date, few studies have investigated the role of ClpP in the survival of E. faecalis, and in enhancing biofilm formation. Therefore, we investigated the role of ClpP in the formation of E. faecalis biofilms.

METHODOLOGY: In our study, we used homologous recombination to construct clpP deleted and clpP complement strains of E. faecalis ATCC 29212. A viable colony counting method was used to analyze the growth patterns of E. faecalis. Crystal violet staining (CV) and confocal scanning laser microscopy (CLSM) were used to characterize biofilm mass formation and scanning electron microscopy (SEM) was used to observe the biofilm microstructure. Data was statistically analyzed via Student's t-test or one-way analysis of variance (ANOVA).

RESULTS: The results exhibited altered growth patterns for the clpP deletion strains and depleted polysaccharide matrix, resulting in reduced biofilm formation capacity compared to the standard strains. Moreover, ClpP was observed to increase biofilm formation in E. faecalis.

CONCLUSION: Our study shows that ClpP can increase biofilm formation in E. faecalis and emphasizes the importance of ClpP as a potential target against E. faecalis.}, } @article {pmid33654415, year = {2021}, author = {Asaad, AM and Ansari, S and Ajlan, SE and Awad, SM}, title = {Epidemiology of Biofilm Producing Acinetobacter baumannii Nosocomial Isolates from a Tertiary Care Hospital in Egypt: A Cross-Sectional Study.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {709-717}, pmid = {33654415}, issn = {1178-6973}, abstract = {OBJECTIVE: This cross-sectional study aims to determine the prevalence and associated risk factors of biofilm-producing A. baumannii nosocomial isolates from a tertiary care hospital, as well as to investigate any possible association of biofilm formation with the distribution of biofilm-related genotypes and antibiotic resistance phenotypes.

METHODS: A total of 94 non-duplicate A. baumannii nosocomial isolates were identified, their biofilm formation was quantitatively detected using the modified microtiter plate assay, and their susceptibilities to different antibiotics were determined using the breakpoint method. Isolates were then subjected to PCR assays targeting bap, ompA and bla PER-1 genes.

RESULTS: The majority (70.1%) of isolates were biofilm producers. The most prevalent biofilm gene was ompA (63.8%), followed by bap (13.8%) and bla PER-1 (10.6%). The presence of multi- and extensive-drug resistance (MDR and XDR) was significantly associated with biofilm producers (p = 0.017 and 0.002, respectively). The length of hospital stay (aOR= 0.023), the presence of ompA gene (aOR = 0.286) or bap gene (aOR = 0.346), ampicillin/sulbactam resistance (aOR = 1), and the presence of MDR (aOR = -0.329) or XDR (aOR = -0.252) were considered significant risk factors associated with biofilm-producing isolates.

CONCLUSION: The high prevalence of biofilm-producing MDR and XDR nosocomial isolates in this study is worrisome and alarming. Characterization of risk factors could help control the continuous selection and transfer of this serious A. baumannii phenotype inside hospitals and improve the quality of patients' care.}, } @article {pmid33653887, year = {2021}, author = {Yanuka-Golub, K and Dubinsky, V and Korenblum, E and Reshef, L and Ofek-Lalzar, M and Rishpon, J and Gophna, U}, title = {Anode Surface Bioaugmentation Enhances Deterministic Biofilm Assembly in Microbial Fuel Cells.}, journal = {mBio}, volume = {12}, number = {2}, pages = {}, pmid = {33653887}, issn = {2150-7511}, mesh = {Bacteria/genetics/growth & development ; *Biodegradation, Environmental ; Bioelectric Energy Sources/microbiology ; Biofilms/*growth & development ; *Electrodes ; *Microbiota ; Wastewater/microbiology ; Water Purification/*methods ; }, abstract = {Microbial fuel cells (MFCs) generate energy while aiding the biodegradation of waste through the activity of an electroactive mixed biofilm. Metabolic cooperation is essential for MFCs' efficiency, especially during early colonization. Thus, examining specific ecological processes that drive the assembly of anode biofilms is highly important for shortening startup times and improving MFC performance, making this technology cost-effective and sustainable. Here, we use metagenomics to show that bioaugmentation of the anode surface with a taxonomically defined electroactive consortium, dominated by Desulfuromonas, resulted in an extremely rapid current density generation. Conversely, the untreated anode surface resulted in a highly stochastic and slower biofilm assembly. Remarkably, an efficient anode colonization process was obtained only if wastewater was added, leading to a nearly complete replacement of the bioaugmented community by Geobacter lovleyi Although different approaches to improve MFC startup have been investigated, we propose that only the combination of anode bioaugmentation with wastewater inoculation can reduce stochasticity. Such an approach provides the conditions that support the growth of specific newly arriving species that positively support the fast establishment of a highly functional anode biofilm.IMPORTANCE Mixed microbial communities play important roles in treating wastewater, in producing renewable energy, and in the bioremediation of pollutants in contaminated environments. While these processes are well known, especially the community structure and biodiversity, how to efficiently and robustly manage microbial community assembly remains unknown. Moreover, it has been shown that a high degree of temporal variation in microbial community composition and structure often occurs even under identical environmental conditions. This heterogeneity is directly related to stochastic processes involved in microbial community organization, similarly during the initial stages of biofilm formation on surfaces. In this study, we show that anode surface pretreatment alone is not sufficient for a substantial improvement in startup times in microbial fuel cells (MFCs), as previously thought. Rather, we have discovered that the combination of applying a well-known consortium directly on the anode surface together with wastewater (including the bacteria that they contain) is the optimized management scheme. This allowed a selected colonization process by the wastewater species, which improved the functionality relative to that of untreated systems.}, } @article {pmid33653399, year = {2021}, author = {Hashimoto, A and Miyamoto, H and Kii, S and Kobatake, T and Shobuike, T and Noda, I and Sonohata, M and Mawatari, M}, title = {Time-dependent efficacy of combination of silver-containing hydroxyapatite coating and vancomycin on methicillin-resistant Staphylococcus aureus biofilm formation in vitro.}, journal = {BMC research notes}, volume = {14}, number = {1}, pages = {81}, pmid = {33653399}, issn = {1756-0500}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Durapatite ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Silver/pharmacology ; *Staphylococcal Infections/drug therapy/prevention & control ; Vancomycin/pharmacology ; }, abstract = {OBJECTIVE: We developed a silver-containing hydroxyapatite (Ag-HA) coating to prevent periprosthetic joint infection (PJI). Methicillin-resistant Staphylococcus aureus (MRSA) is the main PJI-causing bacteria. Previously, we had reported the combined effect of Ag-HA coating and vancomycin (VCM) on MRSA biofilm formation 24 h after MRSA inoculation. In this study, we investigated the time-dependent efficacy of Ag-HA coating and VCM on MRSA biofilm formation on Ti discs in vitro by three-dimensional confocal laser scanning microscopic analysis.

RESULTS: For the Ti VCM and HA VCM groups, the total biofilm volumes per area at 96 h after MRSA inoculation were significantly larger than those at 48 h after MRSA inoculation, respectively (p < 0.001). In contrast, for the Ag-HA VCM group, the total biofilm volume per area at 96 h was significantly smaller than that at 48 h (p < 0.0001). Moreover, 96 h after MRSA inoculation, the total biofilm volume per area of the Ag-HA VCM groups was significantly smaller than those of the Ti VCM and HA VCM groups (p < 0.0001). Thus, the combination of Ag-HA and VCM might be useful for the prevention of MRSA-associated PJI.}, } @article {pmid33653369, year = {2021}, author = {Zhang, Y and Qiu, Y and Xue, X and Zhang, M and Sun, J and Li, X and Hu, L and Yin, Z and Yang, W and Lu, R and Zhou, D}, title = {Transcriptional regulation of the virulence genes and the biofilm formation associated operons in Vibrio parahaemolyticus.}, journal = {Gut pathogens}, volume = {13}, number = {1}, pages = {15}, pmid = {33653369}, issn = {1757-4749}, support = {82072239//National Natural Science Foundation of China/ ; 2020Z102//Jiangsu Planned Projects for Postdoctoral Research Funds/ ; 2020M681513//China Postdoctoral Science Foundation/ ; }, abstract = {BACKGROUND: The membrane fusion protein (mfp) gene locus of Vibrio parahaemolyticus consists of two operons, cpsQ-mfpABC and mfpABC, which are both required for biofilm formation. ToxR and CalR are required for the full virulence of V. parahaemolyticus, and their mutual regulation has been demonstrated. Moreover, cell density-dependent expression of toxR was previously observed in V. parahaemolyticus, but details about the related mechanisms remained unclear. QsvR can work with the master quorum sensing (QS) regulators AphA and OpaR to regulate virulence expression and biofilm formation.

RESULTS: In the present work, we showed that QsvR bound to the promoter-proximal DNA regions of toxR and calR to repress their transcription as well as occupying the regulatory regions of cpsQ-mfpABC and mfpABC to activate their transcription. Thus, we reconstructed the QsvR-dependent promoter organization of toxR, calR, cpsQ-mfpABC, and mfpABC.

CONCLUSION: QsvR directly repressed toxR and calR transcription as well as directly activated cpsQ-mfpABC and mfpABC transcription. The data presented here promotes us to gain deeper knowledge of the regulatory network of the mfp locus in V. parahaemolyticus.}, } @article {pmid33653019, year = {2021}, author = {Pharmaceuticals Editorial Office, }, title = {Retraction: Qian, W., et al. Sanguinarine Inhibits Mono- and Dual-Species Biofilm Formation by Candida albicans and Staphylococcus aureus and Induces Mature Hypha Transition of C. albicans. Pharmacueticals 2020, 13, 13.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {14}, number = {3}, pages = {}, pmid = {33653019}, issn = {1424-8247}, abstract = {The journal retracts the article [...].}, } @article {pmid33652302, year = {2021}, author = {Cortês, IT and Rosalen, PL and Berto, LA and Castro, ML and Pedrini, DL and Porto, AN and Cogo-Müller, K and Nobre Franco, GC}, title = {Effect of adrenaline and noradrenaline on biofilm formation and virulence factors of Streptococcus mutans UA159.}, journal = {Archives of oral biology}, volume = {125}, number = {}, pages = {105091}, doi = {10.1016/j.archoralbio.2021.105091}, pmid = {33652302}, issn = {1879-1506}, mesh = {Biofilms ; Epinephrine ; Gene Expression Regulation, Bacterial ; Humans ; Norepinephrine/pharmacology ; *Streptococcus mutans ; *Virulence Factors ; }, abstract = {OBJECTIVES: To evaluate in vitro the effects of adrenaline and noradrenaline on the biofilm formation on orthodontic brackets, acid production and expression of virulence genes of Streptococcus mutans UA159 (S. mutans).

DESIGN: S. mutans UA159 biofilm was formed on orthodontic brackets under exposure to adrenaline (100 μM), noradrenaline (50 μM) or PBS solution (control group) in triptone-yeast extract with 1 % sucrose. After 24 h, biofilm formation was quantified through Colony Forming Units / mL (CFU/mL) and RNA was extracted to perform gene expression analysis through real-time reverse transcriptase-PCR (RT-qPCR). Evaluation of acid production was carried out on planktonic cultures for 6 h. One-way ANOVA followed by Tukey's test was carried to determine statistical difference. The level of significance was set at 5 %.

RESULTS: Catecholamines stimulated biofilm formation of S. mutans in orthodontic brackets (p < 0,05) but did not interfere with acid production (pH reduction) or the expression of the tested genes related to biofilm formation (gtfB, gtfC, gbpA, gbpB, gbpC, gbpD and brpA), aciduric (relA) and acidogenic properties (ldh).

CONCLUSIONS: The present study was the first to demonstrate that catecholamines can stimulate S. mutans UA159 biofilm formation. These findings can contribute to clarify the role of stress on bacterial metabolism and contribute to the understanding of a possible role on caries development, mainly in orthodontic patients.}, } @article {pmid33650748, year = {2021}, author = {Wang, Y}, title = {Liposome as a delivery system for the treatment of biofilm-mediated infections.}, journal = {Journal of applied microbiology}, volume = {131}, number = {6}, pages = {2626-2639}, doi = {10.1111/jam.15053}, pmid = {33650748}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Drug Delivery Systems ; *Liposomes ; }, abstract = {Biofilm formation by pathogenic microorganisms has been a tremendous challenge for antimicrobial therapies due to various factors. The biofilm matrix sequesters bacterial cells from the exterior environment and therefore prevents antimicrobial agents from reaching the interior. In addition, biofilm surface extracellular polymeric substances can absorb antimicrobial agents and thus reduce their bioavailability. To conquer these protection mechanisms, liposomes have been developed into a drug delivery system for antimicrobial agents against biofilm-mediated infections. The unique characteristics of liposomes, including versatility for cargoes, target-specificity, nonimmunogenicity, low toxicity, and biofilm matrix-/cell membrane-fusogenicity, remarkably improve the effectiveness of antimicrobial agents and minimize recurrence of infections. This review summarizes current development of liposomal carriers for biofilm therapeutics, presents evidence in their practical applications and discusses their potential limitations.}, } @article {pmid33650677, year = {2021}, author = {Espíndola, LCP and do Nascimento, MVMR and do Souto, RM and Colombo, APV}, title = {Antimicrobial susceptibility and virulence of Enterococcus spp. isolated from periodontitis-associated subgingival biofilm.}, journal = {Journal of periodontology}, volume = {92}, number = {11}, pages = {1588-1600}, doi = {10.1002/JPER.20-0815}, pmid = {33650677}, issn = {1943-3670}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Bacterial ; *Enterococcus ; Enterococcus faecalis ; Humans ; Microbial Sensitivity Tests ; *Periodontitis ; Virulence ; }, abstract = {BACKGROUND: This study evaluated the prevalence, virulence and antimicrobial susceptibility of enterococci isolated from the subgingival microbiota of patients with different periodontal status.

METHODS: Subgingival biofilm was obtained from individuals with periodontal health (PH) (n = 139), gingivitis (n = 103), and periodontitis (n = 305) and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial sensitivity was determined by disk diffusion, virulence genes by polymerase chain reaction, and the subgingival microbiota by checkerboard. Differences among groups were assessed by Kruskal-Wallis, Mann-Whitney, and Chi-square tests.

RESULTS: Enterococcus spp. were isolated from 7.4% of all samples; 53.7% were Enterococcus faecalis. They were more prevalent in periodontitis (9.8%) and gingivitis (7.8%) than PH (2.2%; P <0.05), but no differences among stages of disease severity were observed. High rates of low susceptibility/resistance (>64%) to at least one antimicrobial were observed. Predominant virulence factors included ace (64.3%), asa (39.3%), and esp (35.7%). Fusobacterium nucleatum was prevalent in the subgingival microbiota of enterococci+ individuals, whereas Dialister pneumosintes was found in low frequency in patients with bopD+ enterococci. Oral streptococci were prevalent (>70%) in patients carrying enterococci susceptible to doxycycline (P <0.05), usually bopD- and esp- (P <0.01).

CONCLUSIONS: E. faecalis is increased in periodontitis-associated biofilm. Oral enterococci carry virulence genes and express resistance to some antibiotics commonly used in dentistry, such as ciprofloxacin and erythromycin. Specific subgingival taxa are associated with oral enterococci, suggesting they may interact with species of the dysbiotic periodontitis biofilm, constituting a potential source of factors to tissue destruction, antibiotic resistance dissemination, and poor response to periodontal therapy.}, } @article {pmid33650546, year = {2021}, author = {Zafari, M and Adibi, M and Chiani, M and Bolourchi, N and Barzi, SM and Shams Nosrati, MS and Bahari, Z and Shirvani, P and Noghabi, KA and Ebadi, M and Rahimirad, N and Shafiei, M}, title = {Effects of cefazolin-containing niosome nanoparticles against methicillin-resistant Staphylococcus aureus biofilm formed on chronic wounds.}, journal = {Biomedical materials (Bristol, England)}, volume = {16}, number = {3}, pages = {035001}, doi = {10.1088/1748-605X/abc7f2}, pmid = {33650546}, issn = {1748-605X}, mesh = {Animals ; Anti-Bacterial Agents/chemistry ; *Biofilms ; Cefazolin/*chemistry ; Cell Survival ; Drug Delivery Systems ; Fibroblasts/metabolism ; Humans ; Liposomes/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Nanoparticles/*chemistry ; Polymerase Chain Reaction ; Pressure Ulcer/microbiology ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects ; Wound Healing/*drug effects ; }, abstract = {The ability of biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA) causes significant mortality and morbidity in wound infections. Nanoparticles because of the drug concentration increment at the point of contact of nanoparticles and bacteria, and slower release of the drug at the desired location are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections. This study was aimed to evaluate the anti-biofilm activity of cefazolin-loaded nanoparticles against MRSA isolates. The 27 clinical isolates of MRSA were collected from patients with pressure sores and diabetic ulcers referred to Loghman Hospital in Tehran-Iran. MRSA isolates were detected by polymerase chain reaction (PCR) and biochemical tests. Cefazolin-loaded niosome was synthesized using the thin-film hydration method and were characterized by zeta potential measurement and transmission electron microscopy (TEM). The round-shaped cefazolin-loaded niosomes had a diameter of 100 nm and a -63 mV zeta potential. The cefazolin-containing niosomes removed 1, 3, and 5 d old biofilms at the concentration of 128 µg ml[-1], 128 µg ml[-1], and 256 µg ml[-1], respectively. Histological results indicated that BALB/c mice receiving cefazolin-loaded niosomes were treated effectively faster than those treated by cefazolin or untreated group. In conclusion, the cefazolin-loaded niosome could be considered as a promising candidate for the treatment of biofilm-mediated infections of MRSA.}, } @article {pmid33650476, year = {2021}, author = {Ledwoch, K and Magoga, M and Williams, D and Fabbri, S and Walsh, J and Maillard, JY}, title = {Is a reduction in viability enough to determine biofilm susceptibility to a biocide?.}, journal = {Infection control and hospital epidemiology}, volume = {42}, number = {12}, pages = {1486-1492}, doi = {10.1017/ice.2021.42}, pmid = {33650476}, issn = {1559-6834}, mesh = {Biofilms ; *Disinfectants/pharmacology ; Disinfection ; Humans ; Peracetic Acid/pharmacology ; Staphylococcus aureus ; }, abstract = {OBJECTIVE: The abundance and prevalence of dry-surface biofilms (DSBs) in hospitals constitute an emerging problem, yet studies rarely report the cleaning and disinfection efficacy against DSBs. Here, the combined impact of treatments on viability, transferability, and recovery of bacteria from DSBs has been investigated for the first time.

METHODS: Staphylococcus aureus DSBs were produced in alternating 48-hour wet-dry cycles for 12 days on AISI 430 stainless steel discs. The efficacy of 11 commercially available disinfectants, 4 detergents, and 2 contactless interventions were tested using a modified standardized product test. Reduction in viability, direct transferability, cross transmission (via glove intermediate), and DSB recovery after treatment were measured.

RESULTS: Of 11 disinfectants, 9 were effective in killing and removing bacteria from S. aureus DSBs with >4 log10 reduction. Only 2 disinfectants, sodium dichloroisocyanurate 1,000 ppm and peracetic acid 3,500 ppm, were able to lower both direct and cross transmission of bacteria (<2 compression contacts positive for bacterial growth). Of 11 disinfectants, 8 could not prevent DSB recovery for >2 days. Treatments not involving mechanical action (vaporized hydrogen peroxide and cold atmospheric plasma) were ineffective, producing <1 log10 reduction in viability, DSB regrowth within 1 day, and 100% transferability of DSB after treatment.

CONCLUSIONS: Reduction in bacterial viability alone does not determine product performance against biofilm and might give a false sense of security to consumers, manufacturers and regulators. The ability to prevent bacterial transfer and biofilm recovery after treatment requires a better understanding of the effectiveness of biocidal products.}, } @article {pmid33649116, year = {2023}, author = {Zhao, Y and Cai, Y and Chen, Z and Li, H and Xu, Z and Li, W and Jia, J and Sun, Y}, title = {SpoT-mediated NapA upregulation promotes oxidative stress-induced Helicobacter pylori biofilm formation and confers multidrug resistance.}, journal = {Antimicrobial agents and chemotherapy}, volume = {65}, number = {5}, pages = {}, pmid = {33649116}, issn = {1098-6596}, abstract = {Recently, there is increased incidence of drug-resistant Helicobacter pylori infection. Biofilm formation confers multidrug resistance to bacteria. Moreover, it has been found that the formation of biofilm on the surface of gastric mucosa is an important reason for the difficulty of eradication of H. pylori The mechanisms underlying H. pylori biofilm formation in vivo have not been elucidated. Reactive oxygen species (ROS) released by the host immune cells in response to H. pylori infection cannot effectively clear the pathogen. Moreover, the extracellular matrix of the biofilm protects the bacteria against ROS-mediated toxicity. This study hypothesized that ROS can promote H. pylori biofilm formation and treatment with low concentrations of hydrogen peroxide (H2O2) promoted this process in vitro The comparative transcriptome analysis of planktonic and biofilm-forming cells revealed that the expression of SpoT, a (p)ppGpp (guanosine 3'-diphosphate 5'-triphosphate and guanosine 3',5'-bispyrophosphate) synthetase/hydrolase, is upregulated in H2O2-induced biofilms and that knockout of spoT inhibited H. pylori biofilm formation. Additionally, this study examined the key target molecules involved in SpoT regulation using weighted gene co-expression network analysis. The analysis revealed that neutrophil-activating protein (NapA; HP0243) promoted H2O2-induced biofilm formation and conferred multidrug resistance. Furthermore, vitamin C exhibited anti-H. pylori biofilm activity and downregulated the expression of napA in vitro These findings provide novel insight into the clearance of H. pylori biofilms.}, } @article {pmid33649112, year = {2021}, author = {Raval, YS and Flurin, L and Mohamed, A and Greenwood-Quaintance, KE and Beyenal, H and Patel, R}, title = {in vitro Activity of Hydrogen Peroxide and Hypochlorous Acid Generated by Electrochemical Scaffolds Against Planktonic and Biofilm Bacteria.}, journal = {Antimicrobial agents and chemotherapy}, volume = {65}, number = {5}, pages = {}, pmid = {33649112}, issn = {1098-6596}, support = {R01 AI091594/AI/NIAID NIH HHS/United States ; }, abstract = {Hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) are biocides used for cleaning and debriding chronic wound infections, which often harbor drug resistant bacteria. Here, we evaluated the in vitro activity of H2O2 and HOCl against 27 isolates of eight bacterial species involved in wound infections. Minimum inhibitory concentrations (MICs) and minimum biofilm bactericidal concentrations (MBBCs) were measured. When compared to their respective MICs, MBBCs of isolates exposed to H2O2 were 16- to 1,024-fold higher and those exposed to HOCl were 2- to 4-fold higher. We evaluated selection of resistance after exposure of Staphylococcus aureus and Pseudomonas aeruginosa biofilms to 10 iterations of electrochemically generated HOCl or H2O2 delivered using electrochemical scaffolds (e-scaffolds), observing no decrease in anti-biofilm effects with serial exposure to e-scaffold-generated H2O2 or HOCl. 24-hour exposure to H2O2-generating e-scaffolds consistently decreased colony forming units (CFUs) of S. aureus and P. aeruginosa biofilms by ∼5.0-log10 and ∼4.78-log10 through 10 iterations of exposure, respectively. 4-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of S. aureus biofilms by ∼4.9-log10, and 1-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of P. aeruginosa biofilms by ∼1.57-log10 These results suggest that HOCl has similar activity against planktonic and biofilm bacteria, whereas the activity of H2O2 is less against biofilm than planktonic bacteria, and that repeat exposure to either biocide, generated electrochemically under the experimental conditions studied, does not lessen antibiofilm effects.}, } @article {pmid33648189, year = {2021}, author = {Ramires, T and Kleinubing, NR and Iglesias, MA and Vitola, HRS and Núncio, ASP and Kroning, IS and Moreira, GMSG and Fiorentini, ÂM and da Silva, WP}, title = {Genetic diversity, biofilm and virulence characteristics of Listeria monocytogenes in salmon sushi.}, journal = {Food research international (Ottawa, Ont.)}, volume = {140}, number = {}, pages = {109871}, doi = {10.1016/j.foodres.2020.109871}, pmid = {33648189}, issn = {1873-7145}, mesh = {Animals ; Biofilms ; Brazil ; Food Microbiology ; Genetic Variation ; Humans ; *Listeria monocytogenes/genetics ; Salmon ; Virulence/genetics ; }, abstract = {Sushi is a ready-to-eat (RTE) food prepared from raw or cooked fish that is widely consumed worldwide. Listeria monocytogenes is the foodborne pathogen most commonly associated with RTE and fish products. The aim of the present study was to evaluate the presence of L. monocytogenes in salmon sushi commercialized in Pelotas city, Brazil, and to evaluate the genetic diversity, biofilm-forming ability in stainless steel, and virulence characteristics of the isolates. Four sampling events were carried out in seven specialized sushi establishments totaling 28 sushi pools. Listeria monocytogenes was detected in six samples (21.4%) from two establishments (28.6%). All isolates belonged to serotype 4b and carried the prfA, plcA, plcB, hlyA, mpl, actA, inlA, inlC, inlJ, and iap genes. The inlB gene was not detected in two isolates. The PFGE analysis grouped the isolates into four pulsotypes. All isolates had the ability to form biofilm on stainless steel and the average of biofilm formation counts varied between 6.4 and 7.2 log CFU.cm[-2]. The isolates harbored the biofilm-related genes agrA, agrB, agrC, agrD, and prfA, with the exception of two isolates that did not harbor the agrD gene. The presence of L. monocytogenes in RTE sushi is a concern, demonstrating that sushi consumption may be a risk of human listeriosis. Furthermore, it was possible to identify the persistence of this pathogen for at least one month (pulsotypes III and IV), in two establishments (A and G), highlighting the need for improving the cleaning and sanitation procedures in establishments that commercialize RTE sushi.}, } @article {pmid33647404, year = {2021}, author = {Birk, SE and Mazzoni, C and Mobasharah Javed, M and Borre Hansen, M and Krogh Johansen, H and Anders Juul Haagensen, J and Molin, S and Hagner Nielsen, L and Boisen, A}, title = {Co-delivery of ciprofloxacin and colistin using microcontainers for bacterial biofilm treatment.}, journal = {International journal of pharmaceutics}, volume = {599}, number = {}, pages = {120420}, doi = {10.1016/j.ijpharm.2021.120420}, pmid = {33647404}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Ciprofloxacin ; *Colistin ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, abstract = {In many infected patients, bacterial biofilms represent a mode of growth that significantly enhances the tolerance to antimicrobials, leaving the patients with difficult-to-cure infections. Therefore, there is a growing need for effective treatment strategies to combat biofilm infections. In this work, reservoir-based microdevices, also known as microcontainers (MCs), are co-loaded with two antibiotics: ciprofloxacin hydrochloride (CIP) and colistin sulfate (COL), targeting both metabolically active and dormant subpopulations of the biofilm. We assess the effect of the two drugs in a time-kill study of planktonic P. aeruginosa and find that co-loaded MCs are superior to monotherapy, resulting in complete killing of the entire population. Biofilm consortia of P. aeruginosa grown in flow chambers were not fully eradicated. However, antibiotics in MCs work significantly faster than simple perfusion of antibiotics (62.5 ± 8.3% versus 10.6 ± 10.1% after 5 h) in biofilm consortia, showing the potential of the MC-based treatment to minimize the use of antimicrobials in future therapies.}, } @article {pmid33645897, year = {2022}, author = {Pérez-Rodríguez, S and García-Aznar, JM and Gonzalo-Asensio, J}, title = {Microfluidic devices for studying bacterial taxis, drug testing and biofilm formation.}, journal = {Microbial biotechnology}, volume = {15}, number = {2}, pages = {395-414}, pmid = {33645897}, issn = {1751-7915}, mesh = {Bacteria ; Biofilms ; *Lab-On-A-Chip Devices ; *Microfluidics/methods ; }, abstract = {Some bacteria have coevolved to establish symbiotic or pathogenic relationships with plants, animals or humans. With human association, the bacteria can cause a variety of diseases. Thus, understanding bacterial phenotypes at the single-cell level is essential to develop beneficial applications. Traditional microbiological techniques have provided great knowledge about these organisms; however, they have also shown limitations, such as difficulties in culturing some bacteria, the heterogeneity of bacterial populations or difficulties in recreating some physical or biological conditions. Microfluidics is an emerging technique that complements current biological assays. Since microfluidics works with micrometric volumes, it allows fine-tuning control of the test conditions. Moreover, it allows the recruitment of three-dimensional (3D) conditions, in which several processes can be integrated and gradients can be generated, thus imitating physiological 3D environments. Here, we review some key microfluidic-based studies describing the effects of different microenvironmental conditions on bacterial response, biofilm formation and antimicrobial resistance. For this aim, we present different studies classified into six groups according to the design of the microfluidic device: (i) linear channels, (ii) mixing channels, (iii) multiple floors, (iv) porous devices, (v) topographic devices and (vi) droplet microfluidics. Hence, we highlight the potential and possibilities of using microfluidic-based technology to study bacterial phenotypes in comparison with traditional methodologies.}, } @article {pmid33644831, year = {2021}, author = {Lahiri, D and Nag, M and Sarkar, T and Dutta, B and Ray, RR}, title = {Antibiofilm Activity of α-Amylase from Bacillus subtilis and Prediction of the Optimized Conditions for Biofilm Removal by Response Surface Methodology (RSM) and Artificial Neural Network (ANN).}, journal = {Applied biochemistry and biotechnology}, volume = {193}, number = {6}, pages = {1853-1872}, pmid = {33644831}, issn = {1559-0291}, mesh = {Bacillus subtilis/*enzymology ; *Bacterial Proteins/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Hydrogen-Ion Concentration ; *Neural Networks, Computer ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; *alpha-Amylases/chemistry/pharmacology ; }, abstract = {α-amylase is known to have antibiofilm activity against biofilms of both Gram positive and Gram-negative bacterial strains. Partially purified α-amylase from Bacillus subtilis was found to have inhibit biofilm formed by P. aeruginosa and S. aureus. The spectrophotometric and microscopic studies revealed that the antibiofilm efficacy of the working strain is greater than commercially purchased α-amylase. Response surface methodology (RSM) and artificial neural network (ANN) help to predict the optimum conditions [pH 8, treatment time 6 h and enzyme concentration (200 µg/mL)] for maximum biofilm eradication. This was confirmed by several in vitro experiments. Molecular docking interactions of α-amylase with the extracellular polymeric substances (EPS) of both P. aeruginosa and S. aureus indicate towards the existence of an efficient energy driven spontaneous process. Thus, this study highlights a combination of experimental and computational approach showing the naturally extracted α-amylase from B. subtilis having the potency of removing the biofilms of harmful bacterial strains involved in causing various nosocomial infections.}, } @article {pmid33644045, year = {2021}, author = {Chen, X and Iwatani, S and Kitamoto, T and Chibana, H and Kajiwara, S}, title = {The Lack of SNARE Protein Homolog Syn8 Influences Biofilm Formation of Candida glabrata.}, journal = {Frontiers in cell and developmental biology}, volume = {9}, number = {}, pages = {607188}, pmid = {33644045}, issn = {2296-634X}, abstract = {Biofilm formation of Candida species is considered to be a pathogenic factor of host infection. Since biofilm formation of Candida glabrata has not been as well studied as that of Candida albicans, we performed genetic screening of C. glabrata, and three candidate genes associated with biofilm formation were identified. Candida glabrata SYN8 (CAGL0H06325g) was selected as the most induced gene in biofilm cells for further research. Our results indicated that the syn8Δ mutant was defective not only in biofilm metabolic activity but also in biofilm morphological structure and biomass. Deletion of SYN8 seemed to have no effect on extracellular matrix production, but it led to a notable decrease in adhesion ability during biofilm formation, which may be linked to the repression of two adhesin genes, EPA10 and EPA22. Furthermore, hypersensitivity to hygromycin B and various ions in addition to the abnormal vacuolar morphology in the syn8Δ mutant suggested that active vacuolar function is required for biofilm formation of C. glabrata. These findings enhance our understanding of biofilm formation in this fungus and provide information for the development of future clinical treatments.}, } @article {pmid33643239, year = {2021}, author = {Shang, D and Han, X and Du, W and Kou, Z and Jiang, F}, title = {Trp-Containing Antibacterial Peptides Impair Quorum Sensing and Biofilm Development in Multidrug-Resistant Pseudomonas aeruginosa and Exhibit Synergistic Effects With Antibiotics.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {611009}, pmid = {33643239}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa uses quorum sensing (QS) to control virulence, biofilm formation and antibiotic efflux pump expression. The development of effective small molecules targeting the QS system and biofilm formation represents a novel attractive strategy. In this present study, the effects of a series of Trp-containing peptides on the QS-regulated virulence and biofilm development of multidrug-resistant P. aeruginosa, as well as their synergistic antibacterial activity with three classes of traditional chemical antibiotics were investigated. The results showed that Trp-containing peptides at low concentrations reduced the production of QS-regulated virulence factors by downregulating the gene expression of both the las and rhl systems in the strain MRPA0108. Biofilm formation was inhibited in a concentration-dependent manner, which was associated with extracellular polysaccharide production inhibition by downregulating pelA, algD, and pslA transcription. These changes correlated with alterations in the extracellular production of pseudomonal virulence factors and swarming motility. In addition, the combination of Trp-containing peptides at low concentration with the antibiotics ceftazidime and piperacillin provided synergistic effects. Notably, L11W and L12W showed the highest synergy with ceftazidime and piperacillin. A mechanistic study demonstrated that the Trp-containing peptides, especially L12W, significantly decreased β-lactamase activity and expression of efflux pump genes OprM, MexX, and MexA, resulting in a reduction in antibiotic efflux from MRPA0108 cells and thus increasing the antibacterial activity of these antibiotics against MRPA0108.}, } @article {pmid33642784, year = {2021}, author = {Rudenko, P and Sachivkina, N and Vatnikov, Y and Shabunin, S and Engashev, S and Kontsevaya, S and Karamyan, A and Bokov, D and Kuznetsova, O and Vasilieva, E}, title = {Role of microorganisms isolated from cows with mastitis in Moscow region in biofilm formation.}, journal = {Veterinary world}, volume = {14}, number = {1}, pages = {40-48}, pmid = {33642784}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Mastitis is one of the most important diseases of cows and the most expensive pathology for the dairy industry. Therefore, this study was conducted to explore the role of microorganisms isolated from cows with mastitis in the formation of biofilms under the conditions of farm biogeocenosis in the Moscow region.

MATERIALS AND METHODS: Periodic visits to 12 farms in the Moscow region were conducted to explore the microbial profile of the udder of cows with mastitis. During the visits, 103 milk samples from sick animals were collected and examined. Through microbiological analyses, 486 cultures of microorganisms were identified, which are assigned to 11 genera. Mastitis in cows is caused not only by a single pathogen but also by microbial associations, which included two to seven microbial isolates.

RESULTS: It was observed that 309 isolates (63.6%) from the total number of isolated microorganisms could form a biofilm. The ability to form biofilms was most frequently observed in Staphylococcus aureus (18.8%), Escherichia coli (11.9%), and Staphylococcus uberis (11.7%) cultures from the total number of biofilm-forming microbial cultures. Low biofilm-forming ability among the isolated microorganisms was found in lactobacilli, wherein only 20 (22.5%) Lactobacillus strains had the ability to form biofilms. The isolated microorganisms exhibited different sensitivities to antimicrobial agents, which cause difficulty in selecting an antimicrobial agent that would act on all aspects of the parasitocenosis.

CONCLUSION: A high proportion of microorganisms isolated from cows with mastitis have the ability to form biofilms. The isolated microorganisms exhibited different and highly heterogeneous sensitivity to the action of antimicrobial drugs. This causes difficulty in using these tools for the effective control of mastitis in cows, which is frequently caused by pathogenic associations of microbial biofilms. Therefore, it is important to explore novel and more effective methods to combat this disease.}, } @article {pmid33642430, year = {2021}, author = {Kim, CM and Park, G and Ko, YJ and Kang, SH and Jang, SJ}, title = {Relationships between Relative Expression of RND Efflux Pump Genes, H33342 Efflux Activity, Biofilm-Forming Activity, and Antimicrobial Resistance in Acinetobacter baumannii Clinical Isolates.}, journal = {Japanese journal of infectious diseases}, volume = {74}, number = {6}, pages = {499-506}, doi = {10.7883/yoken.JJID.2020.765}, pmid = {33642430}, issn = {1884-2836}, mesh = {Acinetobacter Infections/drug therapy/microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Benzimidazoles/*pharmacology ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial/drug effects/genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Humans ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Real-Time Polymerase Chain Reaction ; }, abstract = {Various mechanisms underlying antimicrobial resistance in Acinetobacter baumannii have been reported. However, the relationships between efflux pump activity, biofilm formation, and antimicrobial resistance in A. baumannii is controversial. In this study, we investigated the relative expression of RND efflux pump genes, H33342 efflux activity, and biofilm-forming activity in 120 A. baumannii clinical isolates, examined their potential relationships with each other, and statistically analyzed their effects on antibiotic resistance. High adeB expression and high H33342 efflux activity were correlated with low biofilm-forming activity. High adeB expression was significantly correlated with resistance to tigecycline and cefotaxime, but not with the multidrug resistance (MDR) phenotype. Importantly, only high adeJ expression was significantly correlated with the MDR phenotype and was correlated with resistance to various antibiotics. However, we found no significant correlation between adeJ expression and biofilm-forming activity. Furthermore, adeG expression was not correlated with antibiotic resistance and biofilm-forming activity. The results of multivariate analysis showed that adeB overexpression and high H33342 efflux activity were related to biofilm-forming activity, and only adeJ overexpression was significantly associated with the MDR phenotype, highlighting the importance of adeJ overexpression.}, } @article {pmid33640751, year = {2021}, author = {Learbuch, KLG and Smidt, H and van der Wielen, PWJJ}, title = {Influence of pipe materials on the microbial community in unchlorinated drinking water and biofilm.}, journal = {Water research}, volume = {194}, number = {}, pages = {116922}, doi = {10.1016/j.watres.2021.116922}, pmid = {33640751}, issn = {1879-2448}, mesh = {Biofilms ; *Drinking Water ; *Microbiota ; Water Microbiology ; Water Supply ; }, abstract = {Biodegradable compounds can cause undesired microbial growth in drinking water systems and these compounds can originate from the water or pipe materials used in drinking water systems. The aim of our study was to determine the influence of different pipe materials on the microbial populations in water and biofilm under semi-stagnant conditions. The microbial communities in biofilm and water, which were in contact with seven different materials, were characterized by determining ATP concentrations, microbial composition gene copy numbers of some specific microbial groups. The ATP concentration in water and biofilm varied between the different materials with glass (negative control) < copper < PVCC < PE-Xc < PE-Xb < PE-100 < PVC-P. Gene copy numbers of Legionella spp., Mycobacterium spp., Pseudomonas spp., Aeromonas spp., fungi and Vermamoeba vermiformis were also higher for PVC-P and PE than for glass, copper and PVCC. The bacterial community composition in water and biofilm varied between materials as well. PERMANOVA and CAP analysis demonstrated that copper and PVC-P are different when compared to the other materials. Furthermore, bacterial community composition and ATP concentrations in water and biofilm were similar after eight and 16 weeks incubation, but differed from results obtained after one week. Finally, the ATP, the specific microbial groups and the bacterial community composition also differed between water and biofilm on each material. We conclude from our study that pipe material is an important factor that influences the biomass concentration, abundance of specific microorganisms and the bacterial community composition in distribution systems with unchlorinated drinking water.}, } @article {pmid33640548, year = {2021}, author = {Duyar, A and Ciftcioglu, V and Cirik, K and Civelekoglu, G and Uruş, S}, title = {Treatment of landfill leachate using single-stage anoxic moving bed biofilm reactor and aerobic membrane reactor.}, journal = {The Science of the total environment}, volume = {776}, number = {}, pages = {145919}, doi = {10.1016/j.scitotenv.2021.145919}, pmid = {33640548}, issn = {1879-1026}, mesh = {Ammonia ; Biofilms ; Bioreactors ; Nitrogen ; Sewage ; *Water Pollutants, Chemical ; }, abstract = {Landfill leachate (LFL) is one of the most serious environmental problems due to the high concentrations of toxic and hazardous matters. Although several physical, chemical, methods have been tested, biological processes and single or multiple-stage combinations of them have been receiving more attention due to their cost-effective and environmentally-friendly manner. The present work recommended coupling of conventional single-stage A/O with moving bed biofilm reactor and membrane bioreactor (AnoxMBBR/AeMBR) for LFL treatment. The system performance was evaluated for 233 d under varying nitrate concentrations (100-1000 mgNO3[-]-N/L), sludge retention time (SRT) (30-90 d), and HRT (24-48 h) in AnoxMBBR, and constant SRT (infinite) and HRT (48 h) in the AeMBR. The best system performances were observed at 1000 mgNO3[-]-N/L concentration, SRT of 90 d and HRT of 48 h, and the average removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH4[+]-N), and nitrate‑nitrogen (NO3[-]N) were 74.2%, 99.7%, and 89.1%, respectively. Besides, the AeMBR was achieved above 99% NH4[+]-N removal and not adversely affected by varying operation conditions of AnoxMBBR. A slight increase in selected phthalic acid ester (PAE) concentrations (diethyl phthalate (DEP), di (2-Ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP)) was detected in the AnoxMBR, and complete PAEs removal was attained in the AeMBR. Mg, Al, Si, Na, Fe was detected by SEM-EDX analyses in both biofilm of AnoxMBBR and the cake layers of AeMBR. Nitrobacter and Nitratireductor which showed a relatively high abundance played an important role in the removal of NH4[+]-N and COD in LFL. The results confirmed that the proposed sequence is efficient for COD removal, nitrogen removal, and PAEs being an acceptable treatment for landfill leachates.}, } @article {pmid33640404, year = {2021}, author = {Jiang, Y and Liu, Y and Zhang, X and Gao, H and Mou, L and Wu, M and Zhang, W and Xin, F and Jiang, M}, title = {Biofilm application in the microbial biochemicals production process.}, journal = {Biotechnology advances}, volume = {48}, number = {}, pages = {107724}, doi = {10.1016/j.biotechadv.2021.107724}, pmid = {33640404}, issn = {1873-1899}, mesh = {*Biofilms ; Fermentation ; *Synthetic Biology ; }, abstract = {Biofilms can be naturally formed through the attachment of microorganisms on the supporting materials. However, natural biofilms formed in the environment may cause some detrimental effects, such as the equipment contamination and food safety issues et al. On the contrary, biofilms mediated microbial fermentation provides a promising approach for the efficient biochemicals production owing to the properties of self-immobilization, high resistance to toxic reactants and maintenance of long-term cells activity. While few reviews have specifically addressed the biological application of biofilms in the microbial fermentation process. Accordingly, this review will comprehensively summarize the biofilms formation mechanism and potential functions in the microbial fermentation process. Furthermore, the construction strategies for the formation of stable biofilms through synthetic biology technology or the modification of suitable supporting materials will be also discussed. The application of biofilms mediated fermentation will provide an outlook for the biorefinery platform in the future.}, } @article {pmid33638013, year = {2021}, author = {Qiao, Y and Jia, R and Luo, Y and Feng, L}, title = {The inhibitory effect of Ulva fasciata on culturability, motility, and biofilm formation of Vibrio parahaemolyticus ATCC17802.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {24}, number = {3}, pages = {301-310}, pmid = {33638013}, issn = {1618-1905}, support = {51709236//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Coculture Techniques ; Humans ; Ulva/*chemistry ; Vibrio Infections/drug therapy ; Vibrio parahaemolyticus/*drug effects/*growth & development ; }, abstract = {The outbreak of vibriosis from Vibrio parahaemolyticus (V. parahaemolyticus) is one of common pathogenic diseases found in the mariculture environment. In this study, the inhibitory effect of Ulva fasciata (U. fasciata) on the culturability, motility, and biofilm formation of V. parahaemolyticus ATCC17802 was examined by co-culturing system. Results showed that both of secretion and live tissue of U. fasciata could convert culturable V. parahaemolyticus ATCC17802 to non-culturable, both reaching more than 99% of inhibition rate after 3-day co-culture, and higher density (12 g L[-1]) of U. fasciata exhibited stronger inhibition. The twitching behavior of V. parahaemolyticus ATCC17802 was more easily affected by U. fasciata than the swimming behavior after 3-day co-culture, with the inhibitory rates varying at the ranges of 1.70-30.29% (twitching behavior) and 10.06-44.86% (swimming behavior) under the different environmental factors (salinity, NO3[-]-N and PO4[3-]-P concentrations), but no significant correlation was found. The greatest inhibition effect on V. parahaemolyticus ATCC17802 biofilm formation occurred at 12 h, with inhibition rates at the range of 11.03-67.10 %, while there was still no significant correlation between inhibition rate and the three environmental factors. The different environmental factors might induce U. fasciata to excrete different levels of secondary metabolites, which caused the various inhibitory effect on the cultivability, motility, and biofilm formation of V. parahaemolyticus ATCC17802.}, } @article {pmid33637573, year = {2021}, author = {Matsumoto, A and Koga, R and Kanaly, RA and Kouzuma, A and Watanabe, K}, title = {Identification of a Diguanylate Cyclase That Facilitates Biofilm Formation on Electrodes by Shewanella oneidensis MR-1.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {9}, pages = {}, pmid = {33637573}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/*physiology ; Bioelectric Energy Sources ; *Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; Electrodes/microbiology ; Escherichia coli Proteins/genetics/*physiology ; Phosphorus-Oxygen Lyases/genetics/*physiology ; Shewanella/genetics/*physiology ; }, abstract = {In many bacteria, cyclic diguanosine monophosphate (c-di-GMP), synthesized by diguanylate cyclase (DGC), serves as a second messenger involved in the regulation of biofilm formation. Although studies have suggested that c-di-GMP also regulates the formation of electrochemically active biofilms (EABFs) by Shewanella oneidensis MR-1, DGCs involved in this process remained to be identified. Here, we report that the SO_1646 gene, hereafter named dgcS, is upregulated under medium flow conditions in electrochemical flow cells (EFCs), and its product (DgcS) functions as a major DGC in MR-1. In vitro assays demonstrated that purified DgcS catalyzed the synthesis of c-di-GMP from GTP. Comparisons of intracellular c-di-GMP levels in the wild-type strain and a dgcS deletion mutant (ΔdgcS mutant) showed that production of c-di-GMP was markedly reduced in the ΔdgcS mutant when cells were grown in batch cultures and on electrodes in EFCs. Cultivation of the ΔdgcS mutant in EFCs also revealed that the loss of DgcS resulted in impaired biofilm formation and decreased current generation. These findings demonstrate that MR-1 uses DgcS to synthesize c-di-GMP under medium flow conditions, thereby activating biofilm formation on electrodes.IMPORTANCE Bioelectrochemical systems (BESs) have attracted wide attention owing to their utility in sustainable biotechnology processes, such as microbial fuel cells and electrofermentation systems. In BESs, electrochemically active bacteria (EAB) form biofilms on electrode surfaces, thereby serving as effective catalysts for the interconversion between chemical and electric energy. It is therefore important to understand mechanisms for the formation of biofilm by EAB grown on electrodes. Here, we show that a model EAB, S. oneidensis MR-1, expresses DgcS as a major DGC, thereby activating the formation of biofilms on electrodes via c-di-GMP-dependent signal transduction cascades. The findings presented herein provide the molecular basis for improving electrochemical interactions between EAB and electrodes in BESs. The results also offer molecular insights into how Shewanella regulates biofilm formation on solid surfaces in the natural environment.}, } @article {pmid33636521, year = {2021}, author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA}, title = {Modeling of the attached and suspended biomass fractions in a moving bed biofilm reactor.}, journal = {Chemosphere}, volume = {275}, number = {}, pages = {129937}, doi = {10.1016/j.chemosphere.2021.129937}, pmid = {33636521}, issn = {1879-1298}, mesh = {*Biofilms ; Biomass ; *Bioreactors ; Waste Disposal, Fluid ; }, abstract = {The performance, kinetics, and stoichiometry of three high-rate moving bed biofilm reactors (MBBRs) were evaluated. A constant surface area loading rate (SALR) and three different hydraulic retention times (HRTs) were utilized to create scenarios where the attached and suspended biomass fractions would differentiate, despite the main design parameter remaining constant. Performance was simulated using BioWin™ 6.0 software. The objective was to evaluate whether a calibrated/validated model could accurately predict experimental results. Initially, a sensitivity analysis was performed to determine influential parameters. The calibration/validation of influential parameters was then conducted via steady-state simulations for two base cases: 1) highest HRT; and 2) lowest HRT. Both sets of calibrated/validated parameters were substantiated using: 1) steady-state simulations at the other HRTs; and 2) dynamic simulations to evaluate the kinetic rates of attached and suspended biomass fractions at all HRTs. Results demonstrated that the model could be calibrated/validated for a single HRT, but could not accurately predict the performance, kinetics, or stoichiometry at other HRTs.}, } @article {pmid33634695, year = {2021}, author = {Dong, Y and Wang, L and Yuan, K and Ji, F and Gao, J and Zhang, Z and Du, X and Tian, Y and Wang, Q and Zhang, L}, title = {Magnetic Microswarm Composed of Porous Nanocatalysts for Targeted Elimination of Biofilm Occlusion.}, journal = {ACS nano}, volume = {15}, number = {3}, pages = {5056-5067}, doi = {10.1021/acsnano.0c10010}, pmid = {33634695}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Magnetic Phenomena ; *Magnetics ; Porosity ; }, abstract = {Biofilm is difficult to thoroughly cure with conventional antibiotics due to the high mechanical stability and antimicrobial barrier resulting from extracellular polymeric substances. Encouraged by the great potential of magnetic micro-/nanorobots in various fields and their enhanced action in swarm form, we designed a magnetic microswarm consisting of porous Fe3O4 mesoparticles (p-Fe3O4 MPs) and explored its application in biofilm disruption. Here, the p-Fe3O4 MPs microswarm (p-Fe3O4 swarm) was generated and actuated by a simple rotating magnetic field, which exhibited the capability of remote actuation, high cargo capacity, and strong localized convections. Notably, the p-Fe3O4 swarm could eliminate biofilms with high efficiency due to synergistic effects of chemical and physical processes: (i) generating bactericidal free radicals (•OH) for killing bacteria cells and degrading the biofilm by p-Fe3O4 MPs; (ii) physically disrupting the biofilm and promoting •OH penetration deep into biofilms by the swarm motion. As a demonstration of targeted treatment, the p-Fe3O4 swarm could be actuated to clear the biofilm along the geometrical route on a 2D surface and sweep away biofilm clogs in a 3D U-shaped tube. This designed microswarm platform holds great potential in treating biofilm occlusions particularly inside the tiny and tortuous cavities of medical and industrial settings.}, } @article {pmid33633716, year = {2021}, author = {Berlec, A and Janež, N and Sterniša, M and Klančnik, A and Sabotič, J}, title = {Expression of NanoLuc Luciferase in Listeria innocua for Development of Biofilm Assay.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {636421}, pmid = {33633716}, issn = {1664-302X}, abstract = {Studies of biofilm formation by bacteria are crucial for understanding bacterial resistance and for development of novel antibacterial strategies. We have developed a new bioluminescence biofilm assay for Listeria innocua, which is considered a non-pathogenic surrogate for Listeria monocytogenes. L. innocua was transformed with a plasmid for inducible expression of NanoLuc luciferase (Nluc). Concentration-dependent bioluminescence signals were obtained over a concentration range of more than three log units. This biofilm assay enables absolute quantification of bacterial cells, with the necessary validation. For biofilm detection and quantification, this "Nluc bioluminescence" method has sensitivity of 1.0 × 10[4] and 3.0 × 10[4] colony forming units (CFU)/mL, respectively, with a dynamic range of 1.0 × 10[4] to 5.0 × 10[7] CFU/mL. These are accompanied by good precision (coefficient of variation, <8%) and acceptable accuracy (relative error for most samples, <15%). This novel method was applied to assess temporal biofilm formation of L. innocua as a function of concentration of inoculant, in comparison with conventional plating and CFU counting, the crystal violet assay, and the resazurin fluorescence assay. Good correlation (r = 0.9684) of this Nluc bioluminescence assay was obtained with CFU counting. The limitations of this Nluc bioluminescence assay include genetic engineering of bacteria and relatively high cost, while the advantages include direct detection, absolute cell quantification, broad dynamic range, low time requirement, and high sensitivity. Nluc-based detection of L. innocua should therefore be considered as a viable alternative or a complement to existing methods.}, } @article {pmid33631591, year = {2021}, author = {Xing, F and Xi, H and Yu, Y and Zhou, Y}, title = {Anode biofilm influence on the toxic response of microbial fuel cells under different operating conditions.}, journal = {The Science of the total environment}, volume = {775}, number = {}, pages = {145048}, doi = {10.1016/j.scitotenv.2021.145048}, pmid = {33631591}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; *Geobacter ; }, abstract = {The response of microorganisms in microbial fuel cells (MFCs) to toxic compounds under different operating conditions, such as flow rate and culture time, was investigated herein. While it has been reported that MFCs can detect some toxic substances, it is unclear if operating conditions affect MFCs toxicity response. In this study, the toxic response time of MFCs decreased when the flow rate increased from 0.5 mL/min to 2 mL/min and then increased with 5 mL/min. The inhibition rates at 0.5 mL/min, 2 mL/min, and 5 mL/min were 8.4% ± 1.6%, 45.1% ± 5.3%, and 4.9% ± 0.3%, respectively. With the increase of culture time from 7 days to 90 days, the toxic response time of MFCs gradually increased. The inhibition rates at culture times of 7 days, 45 days, and 90 days were 45.1% ± 5.3%, 32.6% ± 6.6%, and 23.2% ± 1.3%, respectively. Increasing the culture time will reduce the sensitivity of MFC. The results showed that MFCs can respond quickly at a flow rate of 2 mL/min after cultivation for 7 days. Under these conditions, the power density can reach 1137.0 ± 65.5 mW/m[2], the relative content of Geobacter sp. is 57%, and the ORP of the multilayers changed from -159.2 ± 1.6 mV to -269.9 ± 1.7 mV within 200 μm biofilm thickness. These findings show that increasing the flow rate and shortening the culture time are conducive for the toxicity response of MFCs, which will increase the sensitivity of MFCs in practical applications.}, } @article {pmid33631235, year = {2021}, author = {Weinbren, M and Inkster, T}, title = {The hospital-built environment: biofilm, biodiversity and bias.}, journal = {The Journal of hospital infection}, volume = {111}, number = {}, pages = {50-52}, doi = {10.1016/j.jhin.2021.02.013}, pmid = {33631235}, issn = {1532-2939}, mesh = {*Bias ; *Biodiversity ; *Biofilms ; *Hospitals ; Humans ; }, } @article {pmid33629487, year = {2021}, author = {Silva, NBS and Marques, LA and Röder, DDB}, title = {Diagnosis of biofilm infections: current methods used, challenges and perspectives for the future.}, journal = {Journal of applied microbiology}, volume = {131}, number = {5}, pages = {2148-2160}, doi = {10.1111/jam.15049}, pmid = {33629487}, issn = {1365-2672}, mesh = {*Biofilms ; Humans ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {The diagnosis of biofilms continues to be a challenge, and there is no standardized protocol for such a diagnosis in clinical practice. In addition, some proposed methodologies are expensive to require significant amounts of time and a high number of trained staff, making them impracticable for clinical practice. In recent years, mass spectrophotometry/matrix-assisted laser desorption ionization time of flight (MALDI-TOF) has been applied it in biofilm studies. However, due to several problems and limitations of the technique, MALDI-TOF is far from being the gold standard for identifying biofilm formation. The omics analysis may prove to be a promising strategy for the diagnosis of biofilms in clinical laboratories since it allows the identification of pathogens in less time than needed for conventional techniques and in a more specific manner. However, omic tools are expensive and require qualified technical expertise, and an analysis of the data obtained needs to be careful not to neglect subpopulations in the biofilm. More studies must therefore be developed for creating a protocol that guarantees rapid biofilm identification, ensuring greater chances of success in infection control. This review discusses the current methods of microbial biofilm detection and future perspectives for its diagnosis in clinical practice.}, } @article {pmid33627113, year = {2021}, author = {Vincent-Bugnas, S and Borsa, L and Gruss, A and Lupi, L}, title = {Prioritization of predisposing factors of gingival hyperplasia during orthodontic treatment: the role of amount of biofilm.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {84}, pmid = {33627113}, issn = {1472-6831}, mesh = {Adolescent ; Adult ; Biofilms ; Causality ; Child ; Cross-Sectional Studies ; *Dental Plaque ; Dental Plaque Index ; *Gingival Hyperplasia ; Humans ; Male ; *Orthodontic Brackets/adverse effects ; Young Adult ; }, abstract = {BACKGROUND: The mechanism of gingival growth that may occur during fixed orthodontic treatment is not yet fully understood and the amount of dental plaque is often incriminated. The objective of this study was to evaluate the prevalence of gingival growth during multi-attachment orthodontic treatment and to prioritize its predicting factors, especially the quantity of biofilm.

METHODS: This comprehensive cross-sectional descriptive study was conducted on orthodontic patients aged 9 to 30 years, in good health, treated by a fixed appliance. Periodontal clinical parameters such as plaque index, gingival index, probing pocket depth, periodontal phenotype and gingival enhancement index were recorded. Likewise, the brushing habits and the date of the last scaling were noted. The orthodontic parameters studied were the duration of the treatment, the type of bracket, the alloys used for the arches and the type of ligatures. Descriptive statistics were carried out, and variables presenting p value < 0.25 were included in a multivariate analysis to calculate the Odds Ratio (OR) of gingival enlargement".

RESULTS: A total of 193 patients were included (16.38 ± 4.89 years). Gingival growth occurred for 49.7% of patients included. The predisposing factors for this pathology during fixed orthodontic treatment were conventional metal brackets (p = 0.021), mouth breathing (p = 0.040), male gender (p = 0.035), thick periodontal phenotype (p = 0.043), elastomeric ligations (p = 0.007), duration of treatment (p = 0.022) and presence of plaque (p = 0.004). After achievement of the logistic regression, only two factors remained related to gingival enlargement: metallic brackets (OR: 3.5, 95% CI: 1.1-10.55) and duration of treatment (OR: 2.03, 95% CI: 1.01-4.08). The amount of plaque would not be directly related to the development of gingival increase during orthodontic treatment.

CONCLUSIONS: Among the predisposing factors that underlie gingival growth during multi-attachment therapy, the amount of plaque is not found. The qualitative assessment of the plaque and its evolution during treatment could clarify the role of the biofilm in the occurrence of gingival overgrowth.}, } @article {pmid33626458, year = {2021}, author = {Sriwiriyarat, T and Kuhakaew, S}, title = {Effects of cations on biofilm formation and characteristics in integrated fixed film activated sludge process at different carbon and nitrogen loadings.}, journal = {Chemosphere}, volume = {275}, number = {}, pages = {130002}, doi = {10.1016/j.chemosphere.2021.130002}, pmid = {33626458}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Carbon ; Cations ; *Nitrogen ; *Sewage ; }, abstract = {Both divalent cations including calcium and magnesium play important roles for microbial aggregates in binding to negatively charged functional groups on bacterial surfaces, in extracellular polymeric substances (EPS), and on inorganic materials in flocs and biofilms. Monovalent cations such as sodium and potassium deteriorate the floc structure and physical properties. The Integrated Fixed Activated Sludge (IFAS) process employs fixed film media in the aerobic zone; therefore, both monovalent and divalent cations are involved in the process performances. In this study, the effects of cations indicated as the monovalent to divalent cations (M/D) ratio on the biofilm formation and characteristics, and on the IFAS performances for carbon and ammonium removals were evaluated. The experiments were conducted in three IFAS systems feeding with the same wastewater but different M/D ratios and two carbon and nitrogen loadings. The findings revealed that high monovalent with low divalent cations at the M/D ratios higher than 2.0 produced excessive polysaccharides in EPS resulting in high viscosity of activated sludge flocs causing viscous bulking with high SVI values, decreasing the biofilm formation, and increasing the biofilm sloughing. Increasing of both monovalent and carbon loading increased more polysaccharides in the EPS leading to the failures of IFAS system. Nitrification failed at higher M/D ratios because of less nitrifiers in flocs and biofilm. The M/D ratio less than 2.0 is suggested to minimize the excessive EPS production in the IFAS system, especially at high organic loading.}, } @article {pmid33622537, year = {2021}, author = {Khan, MF and Murphy, CD}, title = {3-Hydroxytyrosol regulates biofilm growth in Cunninghamella elegans.}, journal = {Fungal biology}, volume = {125}, number = {3}, pages = {211-217}, doi = {10.1016/j.funbio.2020.10.011}, pmid = {33622537}, issn = {1878-6146}, mesh = {Biofilms ; *Cunninghamella ; Phenylethyl Alcohol/analogs & derivatives ; }, abstract = {In contrast to yeast biofilms, those of filamentous fungi are relatively poorly understood, in particular with respect to their regulation. Cunninghamella elegans is a filamentous fungus that is of biotechnological interest as it catabolises drugs and other xenobiotics in an analogous manner to animals; furthermore, it can grow as a biofilm enabling repeated batch biotransformations. Precisely how the fungus switches from planktonic to biofilm growth is unknown and the aim of this study was to shed light on the possible mechanism of biofilm regulation. In dimorphic yeasts, alcohols such as tyrosol and 2-phenylethanol are known to control the yeast-to-hypha switch, and a similar molecule might be involved in regulating biofilm in C. elegans. Gas chromatography-mass spectrometry analysis of crude ethyl acetate extracts from supernatants of 72 h planktonic and biofilm cultures revealed 3-hydroxytyrosol as a prominent metabolite. Further quantification revealed that the amounts of the compound in planktonic cultures were substantially higher (>10-fold) than in biofilm cultures. In the presence of exogenous 3-hydroxytyrosol the growth of aerial mycelium was inhibited, and there was selective inhibition of biofilm when it was added to culture medium. There was no biotransformation of the compound when it was added to 72 h-old cultures, in contrast to the related compounds tyrosol and 2-phenylethanol, which were oxidised to a number of products. Therefore, we propose that 3-hydroxytyrosol is a new signalling molecule in fungi, which regulates biofilm growth.}, } @article {pmid33621482, year = {2021}, author = {Tkachenko, AG and Kashevarova, NM and Sidorov, RY and Nesterova, LY and Akhova, AV and Tsyganov, IV and Vaganov, VY and Shipilovskikh, SA and Rubtsov, AE and Malkov, AV}, title = {A synthetic diterpene analogue inhibits mycobacterial persistence and biofilm formation by targeting (p)ppGpp synthetases.}, journal = {Cell chemical biology}, volume = {28}, number = {10}, pages = {1420-1432.e9}, doi = {10.1016/j.chembiol.2021.01.018}, pmid = {33621482}, issn = {2451-9448}, mesh = {Anti-Bacterial Agents/chemical synthesis/metabolism/pharmacology ; Bacterial Proteins/antagonists & inhibitors/*metabolism ; Binding Sites ; Biofilms/*drug effects ; Diterpenes/chemistry/metabolism/*pharmacology ; Ligases/antagonists & inhibitors/*metabolism ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Mycobacterium smegmatis/drug effects/*enzymology/physiology ; Protein Structure, Tertiary ; }, abstract = {Bacterial persistence coupled with biofilm formation is directly associated with failure of antibiotic treatment of tuberculosis. We have now identified 4-(4,7-DiMethyl-1,2,3,4-tetrahydroNaphthalene-1-yl)Pentanoic acid (DMNP), a synthetic diterpene analogue, as a lead compound that was capable of suppressing persistence and eradicating biofilms in Mycobacterium smegmatis. By using two reciprocal experimental approaches - ΔrelMsm and ΔrelZ gene knockout mutations versus relMsm and relZ overexpression technique - we showed that both RelMsm and RelZ (p)ppGpp synthetases are plausible candidates for serving as targets for DMNP. In vitro, DMNP inhibited (p)ppGpp-synthesizing activity of purified RelMsm in a concentration-dependent manner. These findings, supplemented by molecular docking simulation, suggest that DMNP targets the structural sites shared by RelMsm, RelZ, and presumably by a few others as yet unidentified (p)ppGpp producers, thereby inhibiting persister cell formation and eradicating biofilms. Therefore, DMNP may serve as a promising lead for development of antimycobacterial drugs.}, } @article {pmid33620656, year = {2021}, author = {Püning, C and Su, Y and Lu, X and Gölz, G}, title = {Molecular Mechanisms of Campylobacter Biofilm Formation and Quorum Sensing.}, journal = {Current topics in microbiology and immunology}, volume = {431}, number = {}, pages = {293-319}, pmid = {33620656}, issn = {0070-217X}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Campylobacter ; *Quorum Sensing ; Virulence ; }, abstract = {Even though Campylobacter spp. are known to be fastidious organisms, they can survive within the natural environment. One mechanism to withstand unfavourable conditions is the formation of biofilms, a multicellular structure composed of different bacterial and other microbial species which are embedded in an extracellular matrix. High oxygen levels, low substrate concentrations and the presence of external DNA stimulate the biofilm formation by C. jejuni. These external factors trigger internal adaptation processes, e.g. via regulating the expression of genes encoding proteins required for surface structure formation, as well as motility, stress response and antimicrobial resistance. Known genes impacting biofilm formation will be summarized in this review. The formation of biofilms as well as the expression of virulence genes is often regulated in a cell density depending manner by quorum sensing, which is mediated via small signalling molecules termed autoinducers. Even though quorum sensing mechanisms of other bacteria are well understood, knowledge on the role of these mechanisms in C. jejuni biofilm formation is still scarce. The LuxS enzyme involved in generation of autoinducer-2 is present in C. jejuni, but autoinducer receptors have not been identified so far. Phenotypes of C. jejuni strains lacking a functional luxS like reduced growth, motility, oxygen stress tolerance, biofilm formation, adhesion, invasion and colonization are also summarized within this chapter. However, these phenotypes are highly variable in distinct C. jejuni strains and depend on the culture conditions applied.}, } @article {pmid33619697, year = {2021}, author = {Harada, AMM and Nascimento, MS}, title = {Effect of dry sanitizing methods on Bacillus cereus biofilm.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {2}, pages = {919-926}, pmid = {33619697}, issn = {1678-4405}, support = {132828/2018-9//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Bacillus cereus/drug effects/*physiology ; Biofilms/drug effects/*growth & development ; Colony Count, Microbial ; Desiccation/*methods ; Disinfectants/pharmacology ; Disinfection/*methods ; Food Microbiology ; Hot Temperature ; Polypropylenes ; Stainless Steel ; }, abstract = {Bacillus cereus is a relevant foodborne pathogen and biofilm producer which can contaminate and persist in the processing environment of both high and low water activity foods. Because of this, it is crucial to understand better the resistance of this pathogen biofilm to different sanitation methods. The aim of this study was to evaluate the efficacy of dry sanitizing treatments against B. cereus biofilm formed on stainless steel (SS) and polypropylene (PP). Biofilm formation was held through the static method at 25 °C. After 4 days of incubation, coupons were exposed for up to 30 min to UV-C light, dry heat, gaseous ozone, 70% ethanol, and a commercial sanitizer. Sodium hypochlorite (200 mg/l) was also tested in two different pH values (7 and 11) for comparison purposes. In general, the surface material did not influence (p > 0.05) the performance of the treatments. From 10 min of exposure, 70% ethanol and the commercial product caused the lowest reductions on both surfaces. In addition, dry heat exhibited a poor performance on PP, with reductions < 1 log CFU/cm[2]. UV-C light on SS and PP and ozone on PP achieved reductions around 2 log CFU/cm[2] after 30 min. The same level of reduction was obtained after 5 or 10 min using sodium hypochlorite (200 mg/l). Therefore, the results showed that dry sanitizing methods are not as effective as sodium hypochlorite against B. cereus biofilms. Further studies to evaluate the efficacy of the combination of dry methods are necessary.}, } @article {pmid33619696, year = {2021}, author = {Villa-García, LD and Márquez-Preciado, R and Ortiz-Magdaleno, M and Patrón-Soberano, OA and Álvarez-Pérez, MA and Pozos-Guillén, A and Sánchez-Vargas, LO}, title = {Antimicrobial effect of gold nanoparticles in the formation of the Staphylococcus aureus biofilm on a polyethylene surface.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {52}, number = {2}, pages = {619-625}, pmid = {33619696}, issn = {1678-4405}, support = {PAPIIT IT203618//Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Gold/*pharmacology ; Humans ; Metal Nanoparticles/*toxicity ; Microbial Viability/drug effects ; Polyethylene/analysis ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus aureus/*drug effects/growth & development/physiology ; }, abstract = {The main of this study was to evaluate the inhibitory effect on the in vitro formation of the Staphylococcus aureus biofilm formed on a polyethylene (PE) surface with a nanostructured Gold (Au) coating for medical devices. An experimental in vitro study was carried out using PE discs with an Au nanoparticle coating (AuNPs) on one side (experimental group) and without coating on the other (control group); the discs were mounted in the CDC biofilm reactor adding broth of yeast-dextrose-peptone (YPD) sterile culture inoculated with S. aureus in a cell suspension (5 × 10[8] cells/ml). The specimens were evaluated at different times (6, 12, 24, 48, 72 h) and stained with the Live/Dead Bacterial Viability Kit (Invitrogen) for observation, analysis, and quantification with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results showed that as evaluation time passed an increasing of S. aureus biofilm formation was observed in the control group, in the experimental group, a statistically significant biofilm inhibition was observed with respect to the AuNPs uncoated specimens (p ≤ 0.05) and showed a ratio of almost 4:1 viable/nonviable in the biofilm of the uncoated surfaces, with a difference > 5 Log10 in the CFU counts. The PE with AuNP coating showed an inhibitory effect on the biofilm formation of S. aureus.}, } @article {pmid33618967, year = {2021}, author = {Kniha, K and Heussen, N and Modabber, A and Hölzle, F and Möhlhenrich, SC}, title = {The effect of zirconia and titanium surfaces on biofilm formation and on host-derived immunological parameters.}, journal = {International journal of oral and maxillofacial surgery}, volume = {50}, number = {10}, pages = {1361-1374}, doi = {10.1016/j.ijom.2021.01.021}, pmid = {33618967}, issn = {1399-0020}, mesh = {Biofilms ; *Dental Implants ; Humans ; Surface Properties ; *Titanium ; Zirconium ; }, abstract = {The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P< 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.}, } @article {pmid33618584, year = {2021}, author = {Li, P and Gao, Z and Tan, Z and Xiao, J and Wei, L and Chen, Y}, title = {New developments in anti-biofilm intervention towards effective management of orthopedic device related infections (ODRI's).}, journal = {Biofouling}, volume = {37}, number = {1}, pages = {1-35}, doi = {10.1080/08927014.2020.1869725}, pmid = {33618584}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; Biofilms ; Humans ; Prostheses and Implants ; *Prosthesis-Related Infections/drug therapy ; }, abstract = {Orthopedic device related infections (ODRI's) represent a difficult to treat situation owing to their biofilm based nature. Biofilm infections once established are difficult to eradicate even with an aggressive treatment regimen due to their recalcitrance towards antibiotics and immune attack. The involvement of antibiotic resistant pathogens as the etiological agent further worsens the overall clinical picture, pressing on the need to look into alternative treatment strategies. The present review highlightes the microbiological challenges associated with treatment of ODRI's due to biofilm formation on the implant surface. Further, it details the newer anti-infective modalities that work either by preventing biofilm formation and/or through effective disruption of the mature biofilms formed on the medical implant. The study, therefore aims to provide a comprehensive insight into the newer anti-biofilm interventions (non-antibiotic approaches) and a better understanding of their mechanism of action essential for improved management of orthopedic implant infections.}, } @article {pmid33618189, year = {2021}, author = {Scarabotti, F and Rago, L and Bühler, K and Harnisch, F}, title = {The electrode potential determines the yield coefficients of early-stage Geobacter sulfurreducens biofilm anodes.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {140}, number = {}, pages = {107752}, doi = {10.1016/j.bioelechem.2021.107752}, pmid = {33618189}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/*microbiology ; *Biofilms ; Biomass ; Electricity ; Electrodes ; Geobacter/*physiology ; Kinetics ; Thermodynamics ; }, abstract = {Geobacter sulfurreducens is the model for electroactive microorganisms (EAM). EAM can use solid state terminal electron acceptors (TEA) including anodes via extracellular electron transfer (EET). Yield coefficients relate the produced cell number or biomass to the oxidized substrate or the reduced TEA. These data are not yet sufficiently available for EAM growing at anodes. Thus, this study provides information about kinetics as well as yield coefficients of early-stage G. sulfurreducens biofilms using anodes as TEA at the potentials of -200 mV, 0 mV and +200 mV (vs. Ag/AgCl sat. KCl). The selected microorganism was therefore cultivated in single and double chamber batch reactors on graphite or AuPd anodes. Interestingly, whereas the lag time and maximum current density within 12 days of growth differed, the anode potential does not influence the coulombic efficiency and the formal potential of the EET, which remains constant for all the experiments at ~ -300 to -350 mV. We demonstrated for the first time that the anode potential has a strong influence on single cell yield coefficients which ranged from 2.69 × 10[12] cells mole-[-1] at -200 mV and 1.48 × 10[12] cells mole-[-1] at 0 mV to 2.58 × 10[11] cells mole-[-1] at +200 mV in single chamber reactors and from 1.15 × 10[12] cells mole-[-1] at -200 mV to 8.98× 10[11] cells mole-[-1] at 0 mV in double chamber reactors. This data can be useful for optimization and scaling-up of primary microbial electrochemical technologies.}, } @article {pmid33618119, year = {2021}, author = {Pu, Y and Pan, J and Yao, Y and Ngan, WY and Yang, Y and Li, M and Habimana, O}, title = {Ecotoxicological effects of erythromycin on a multispecies biofilm model, revealed by metagenomic and metabolomic approaches.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {276}, number = {}, pages = {116737}, doi = {10.1016/j.envpol.2021.116737}, pmid = {33618119}, issn = {1873-6424}, mesh = {Biofilms ; *Erythromycin/toxicity ; Metabolomics ; Metagenome ; *Microbiota ; }, abstract = {The presence of antibiotics such as erythromycin, even in trace amounts, has long been acknowledged for negatively impacting ecosystems in freshwater environments. Although many studies have focused on the impact of antibiotic pollution at a macroecological level, the impact of erythromycin on microecosystems, such as freshwater biofilms, is still not fully understood. This knowledge gap may be attributed to the lack of robust multispecies biofilm models for fundamental investigations. Here, we used a lab-cultured multispecies biofilm model to elucidate the holistic response of a microbial community to erythromycin exposure using metagenomic and metabolomic approaches. Metagenomic analyses revealed that biofilm microbial diversity did not alter following erythromycin exposure. Notably, certain predicted metabolic pathways such as cell-cell communication pathways, amino acid metabolism, and peptidoglycan biosynthesis, mainly by the phyla Actinobacteria, Alpha/Beta-proteobacteria, Bacteroidetes, and Verrucomicrobia, were found to be involved in the maintenance of homeostasis-like balance in the freshwater biofilm. Further untargeted metabolomics data highlighted changes in lipid metabolism and linoleic acid metabolism and their related molecules as a direct consequence of erythromycin exposure. Overall, the study presented a unique picture of how multispecies biofilms respond to single environmental stress exposures. Moreover, the study demonstrated the feasibility of using lab simulated multispecies biofilms for investigating their interaction and reactivity of specific bioactive compounds or pollutants at a fundamental level.}, } @article {pmid33618061, year = {2021}, author = {Mea, HJ and Yong, PVC and Wong, EH}, title = {An overview of Acinetobacter baumannii pathogenesis: Motility, adherence and biofilm formation.}, journal = {Microbiological research}, volume = {247}, number = {}, pages = {126722}, doi = {10.1016/j.micres.2021.126722}, pmid = {33618061}, issn = {1618-0623}, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/drug effects/genetics/*metabolism/*pathogenicity ; Animals ; Biofilms/*growth & development ; Cross Infection/microbiology ; Disease Models, Animal ; Drug Resistance, Multiple, Bacterial/drug effects ; Host-Pathogen Interactions ; Humans ; Sepsis ; Virulence Factors/genetics ; }, abstract = {The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.}, } @article {pmid33617496, year = {2021}, author = {Tao, R and Zheng, X and Guo, X and Li, M and Shen, S and Yang, M and Sun, Y and Wu, F}, title = {Pilot-scale enrichment of anammox biofilm using secondary effluent as source water.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {83}, number = {4}, pages = {894-905}, doi = {10.2166/wst.2021.015}, pmid = {33617496}, issn = {0273-1223}, mesh = {*Ammonium Compounds ; Biofilms ; *Bioreactors ; Nitrification ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater ; Water ; }, abstract = {Enough biomass of anaerobic ammonium oxidation (anammox) bacteria is essential for maintaining a stable partial nitrification/anammox (PN/A) wastewater treatment system. Present enrichment procedures are mainly labor-intensive and inconvenient for up-scaling. A simplified procedure was developed for enrichment of anammox biofilm by using secondary effluent as source water with no supplement of mineral medium and unstrict control of influent dissolved oxygen (DO). Anammox biofilm was successfully enriched in two pilot-scale reactors (XQ-cul and BT-cul) within 250 and 120 days, respectively. The specific anammox activity increased rapidly during the last 2 months in both reactors and achieved 2.54 g N2-N/(m[2]·d) in XQ-cul and 1.61 g N2-N/(m[2]·d) in BT-cul. Similar microbial diversity and community structure were obtained in the two reactors despite different secondary effluent being applied from two wastewater treatment plants. Anaerobic ammonium oxidizing bacteria genera abundance reached up to 37.4% and 43.1% in XQ-cul and BT-cul biofilm, respectively. Candidatus Brocadia and Ca. Kuenenia dominated the enriched biofilm. A negligible adverse effect of residual organics and influent DO was observed by using secondary effluent as source water. This anammox biofilm enrichment procedure could facilitate the inoculation and/or bio-augmentation of large-scale mainstream PN/A reactors.}, } @article {pmid33617494, year = {2021}, author = {Zhang, Y and Ge, H and Lin, W and Song, Y and Ge, F and Huang, X and Meng, X}, title = {Effect of different disinfection treatments on the adhesion and separation of biofilm on stainless steel surface.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {83}, number = {4}, pages = {877-885}, doi = {10.2166/wst.2021.028}, pmid = {33617494}, issn = {0273-1223}, mesh = {Bacterial Adhesion ; Biofilms ; *Disinfectants ; Disinfection ; *Stainless Steel ; Surface Properties ; }, abstract = {Attachment and separation of sulfate-reducing bacteria (SRB) biofilm on stainless steel (SS) in simulated cooling water with and without different sterilization treatments was investigated by calculation of surface energy, theoretical work of adhesion and analysis of Scanning Electron Microscope/Energy Dispersive Spectrometer. Two types of biocides, glutaraldehyde and Polyhexamethylene guanidine (PHMG), and electromagnetic treatment were used in this paper. The results show that PHMG had the best bactericidal performance, followed by glutaraldehyde, and electromagnetic treatment was the lowest one. The theoretical work of adhesion was used to quantitatively evaluate the adhesion of biofilm on the surface of the metal. Theoretical work of adhesion between biofilm and SS in simulated cooling water increased with time. The theoretical adhesion work and adhesive capacity of biofilm to SS surface increased after treating with glutaraldehyde while decreasing after treating with PHMG and electromagnetic field. As the theoretical adhesion work decreased, the biofilm was gradually removed from the stainless steel surface. On the contrary, the biofilm adhered more firmly. The results of SEM were also consistent with the calculation results of theoretical adhesion work. The results obtained indicated that electromagnetic treatment had the lowest effect in sterilization but the best in biofilm separation.}, } @article {pmid33617220, year = {2021}, author = {Su, C and Ye, Y and Qiu, H and Zhu, Y}, title = {Solvent-Free Fabrication of Self-Regenerating Antibacterial Surfaces Resisting Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {8}, pages = {10553-10563}, doi = {10.1021/acsami.0c20033}, pmid = {33617220}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*chemistry ; Dimethylamines/chemistry/*pharmacology ; Escherichia coli/drug effects/physiology ; Microbial Sensitivity Tests ; Polymethacrylic Acids/*chemistry ; Polystyrenes/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/physiology ; Urinary Catheters/microbiology ; }, abstract = {Biofilm formation on indwelling medical devices is a major cause of hospital-acquired infections. Monofunctional antibacterial surfaces have been developed to resist the formation of biofilms by killing bacteria on contact, but the adsorption of killed bacterial cells and debris gradually undermines the function of these surfaces. Here, we report a facile approach to produce an antibacterial surface that can regenerate its function after contamination. The self-regenerating surface was achieved by sequential deposition of alternating antibacterial and biodegradable layers of coating using a solvent-free initiated chemical vapor deposition method. As the top antibacterial layer gradually loses its killing ability due to the accumulation of debris, the underlying biodegradable layer degrades, shedding off the top surface layers and exposing another fresh antibacterial surface. Urinary catheters coated with monofunctional and self-regenerating antibacterial coatings both showed more than 99% bacterial killing ability at the initial antibacterial test, but the monofunctional surface lost its killing ability after continued exposure to concentrated bacterial solution, whereas the self-regenerating surfaces regained strong bacterial killing ability after prolonged exposure. Employing poly(methacrylic anhydride) and its copolymers with varied composition as the degrading layer, the degradation kinetics can be well-tailored and the self-regeneration duration spanned from minutes to days. The designed self-regenerating antibacterial surfaces could provide an effective approach to resist biofilm formation and extend the service life of indwelling medical devices.}, } @article {pmid33616592, year = {2021}, author = {Quan, K and Jiang, G and Liu, J and Zhang, Z and Ren, Y and Busscher, HJ and van der Mei, HC and Peterson, BW}, title = {Influence of interaction between surface-modified magnetic nanoparticles with infectious biofilm components in artificial channel digging and biofilm eradication by antibiotics in vitro and in vivo.}, journal = {Nanoscale}, volume = {13}, number = {8}, pages = {4644-4653}, doi = {10.1039/d0nr08537e}, pmid = {33616592}, issn = {2040-3372}, mesh = {Animals ; *Anti-Bacterial Agents/pharmacology ; Biofilms ; Gentamicins/pharmacology ; Humans ; *Magnetite Nanoparticles ; Mice ; Staphylococcus aureus ; }, abstract = {Magnetic targeting of antimicrobial-loaded magnetic nanoparticles to micrometer-sized infectious biofilms is challenging. Bacterial biofilms possess water channels that facilitate transport of nutrient and metabolic waste products, but are insufficient to allow deep penetration of antimicrobials and bacterial killing. Artificial channel digging in infectious biofilms involves magnetically propelling nanoparticles through a biofilm to dig additional channels to enhance antimicrobial penetration. This does not require precise targeting. However, it is not known whether interaction of magnetic nanoparticles with biofilm components impacts the efficacy of antibiotics after artificial channel digging. Here, we functionalized magnetic-iron-oxide-nanoparticles (MIONPs) with polydopamine (PDA) to modify their interaction with staphylococcal pathogens and extracellular-polymeric-substances (EPS) and relate the interaction with in vitro biofilm eradication by gentamicin after magnetic channel digging. PDA-modified MIONPs had less negative zeta potentials than unmodified MIONPs due to the presence of amino groups and accordingly more interaction with negatively charged staphylococcal cell surfaces than unmodified MIONPs. Neither unmodified nor PDA-modified MIONPs interacted with EPS. Concurrently, use of non-interacting unmodified MIONPs for artificial channel digging in in vitro grown staphylococcal biofilms enhanced the efficacy of gentamicin more than the use of interacting, PDA-modified MIONPs. In vivo experiments in mice using a sub-cutaneous infection model confirmed that non-interacting, unmodified MIONPs enhanced eradication by gentamicin of Staphylococcus aureus Xen36 biofilms about 10 fold. Combined with the high biocompatibility of magnetic nanoparticles, these results form an important step in understanding the mechanism of artificial channel digging in infectious biofilms for enhancing antibiotic efficacy in hard-to-treat infectious biofilms in patients.}, } @article {pmid33616555, year = {2021}, author = {de Arruda, CNF and Salles, MM and Oliveira, VC and Macedo, AP and da Silva, CHL and Paranhos, HFO}, title = {Using denture cleansers to control biofilm from dentures and brushes: A randomized crossover clinical trial.}, journal = {The International journal of prosthodontics}, volume = {34}, number = {3}, pages = {291–299}, doi = {10.11607/ijp.6665}, pmid = {33616555}, issn = {1942-4426}, mesh = {*Biofilms ; Colony Count, Microbial ; *Denture Cleansers ; Dentures ; Humans ; Streptococcus mutans ; }, abstract = {PURPOSE: To evaluate the effects of 0.2% sodium hypochlorite, Efferdent (Prestige Consumer Healthcare), and 6.25% Ricinus communis on biofilm removal and antimicrobial action on dentures and brushes using nonimmersion or immersion protocols for the brushes.

MATERIALS AND METHODS: A total of 45 denture wearers were randomly assigned to a denture immersion protocol for 7 days: 0.85% saline solution for 20 minutes (control); 0.2% sodium hypochlorite for 20 minutes (SH); Efferdent for 3 minutes; or 6.25% Ricinus communis for 20 minutes (RC). The participants were also randomized to immersion (n = 23) or no immersion (n = 22) of their brushes with their dentures in the same solutions. For biofilm evaluation, the dentures were stained and photographed, and the area of the biofilm was measured using Image Tool 3.0 (University of Texas Health Science Center). To evaluate microbial load on dentures and brushes, the biofilm was collected, and the Candida spp and Streptococcus mutans colonies were counted.

RESULTS: The SH, Efferdent, and RC groups showed reduced biofilm and Candida spp on dentures regardless of the immersion protocol for the brushes. However, no difference was found in the Candida spp counts collected from the brushes immersed compared to the brushes not immersed in the solutions. The SH and Efferdent groups showed reduced S mutans on both dentures and brushes, except for in the nonimmersion subgroups.

CONCLUSION: All solutions reduced denture biofilm and microbial load. However, immersion of brushes in the solutions did not contribute to reducing the microbial load.}, } @article {pmid33616004, year = {2022}, author = {Silva, BG and Santos Oliveira, JM and Zamariolli Damianovic, MHR and Foresti, E}, title = {Foam aerated biofilm reactor: a novel counter-diffusional process for COD and nitrogen removal from low COD/N effluents.}, journal = {Environmental technology}, volume = {43}, number = {17}, pages = {2671-2683}, doi = {10.1080/09593330.2021.1893830}, pmid = {33616004}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; *Nitrogen ; Wastewater ; }, abstract = {Counter-diffusional biofilms are efficient in the removal of nitrogen from low strength wastewaters. Although counter-diffusion is usually established using expensive gas-permeable membranes, a polyurethane sheet is used to separate the aerobic and anoxic environments in the novel foam aerated biofilm reactor (FABR). Foam sheets with thicknesses of 10, 5 and 2 mm and synthetic wastewater with COD/N ratios of 5 and 2.5 were evaluated. The 2 mm thick foam reactor did not show good biomass adherence and, therefore, did not show N removal efficiency. The 5 and 10 mm reactors, in both COD/N ratios, showed similar total nitrogen and COD removal performance, up to 60% and 80%, respectively. The denitrification efficiency was close to 100% throughout the experimental period. Nitrification efficiency decreased with microbial growth, which was recovered after removal of excessive biomass. Lower values of polyurethane foam thickness and COD/N ratio did not provide a higher nitrification rate, as expected. The increase in resistance to mass transfer was associated with the growth of biomass attached to the foam rather than to its thickness and resulted in specialization of the microbial communities as revealed by 16S amplicon sequencing. FABR reveals as a promising alternative for simultaneous removal of nitrogen and COD from low COD/N ratio wastewaters.}, } @article {pmid33615940, year = {2022}, author = {Shastry, RP and Ghate, SD and Sukesh Kumar, B and Srinath, BS and Kumar, V}, title = {Vanillin derivative inhibits quorum sensing and biofilm formation in Pseudomonas aeruginosa: a study in a Caenorhabditis elegans infection model.}, journal = {Natural product research}, volume = {36}, number = {6}, pages = {1610-1615}, doi = {10.1080/14786419.2021.1887866}, pmid = {33615940}, issn = {1478-6427}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Benzaldehydes ; Biofilms ; Caenorhabditis elegans ; Molecular Docking Simulation ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Vanillin and its derivative, (4-((E)-(4-hydroxy-2-methylphenylimino) methyl)-2-methoxyphenol (MMP) were showed clear inhibition of violacein and pyocyanin at sub-MICs indicating a possible quorum quenching effect of both the compounds. MMP was able to inhibit the biofilm formation in Pseudomonas aeruginosa PAO1 at 125 μg/mL (p < 0.05), while vanillin at 250 μg/mL (p < 0.05) indicating that they act against quorum sensing regulated biofilm formation. The inhibition of biofilm was confirmed by visualization through fluorescence microscopy followed by docking analysis of molecules against quorum sensing activator proteins. Caenorhabditis elegans survival assay revealed that vanillin and MMP were able to increase survival of C. elegans from P. aeruginosa PAO1 infection. The study showed that the potent features of the MMP and vanillin in inhibiting the quorum sensing regulated virulence and biofilm, which was proved in C. elegans infection model as well as molecular docking studies.}, } @article {pmid33615928, year = {2021}, author = {Kuiper, JWP and Hogervorst, JMA and Herpers, BL and Bakker, AD and Klein-Nulend, J and Nolte, PA and Krom, BP}, title = {The novel endolysin XZ.700 effectively treats MRSA biofilms in two biofilm models without showing toxicity on human bone cells in vitro.}, journal = {Biofouling}, volume = {37}, number = {2}, pages = {184-193}, doi = {10.1080/08927014.2021.1887151}, pmid = {33615928}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/toxicity ; Biofilms ; Endopeptidases ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Osteocytes ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {In this in vitro study the effect of XZ.700, a new endolysin, on methicillin resistant Staphylococcus aureus (MRSA) biofilms grown on titanium was evaluated. Biofilms of S. aureus USA300 were grown statically and under flow, and treatment with XZ.700 was compared with povidone-iodine (PVP-I) and gentamicin. To evaluate the cytotoxic effects of XZ.700 and derived biofilm lysates, human osteocyte-like cells were exposed to biofilm supernatants, and metabolism and proliferation were quantified. XZ.700 showed a significant, concentration dependent reduction in biofilm viability, compared with carrier controls. Metabolism and proliferation of human osteocyte-like cells were not affected by XZ.700 or lysates, unlike PVP-I and gentamicin lysates which significantly inhibited proliferation. Using time-lapse microscopy, rapid biofilm killing and removal was observed for XZ.700. In comparison, PVP-I and gentamicin showed slower biofilm killing, with no apparent biofilm removal. In conclusion, XZ.700 reduced MRSA biofilms, especially under flow condition, without toxicity for surrounding bone cells.}, } @article {pmid33615654, year = {2021}, author = {Ruiz, A and Herráez, M and Costa-Gutierrez, SB and Molina-Henares, MA and Martínez, MJ and Espinosa-Urgel, M and Barriuso, J}, title = {The architecture of a mixed fungal-bacterial biofilm is modulated by quorum-sensing signals.}, journal = {Environmental microbiology}, volume = {23}, number = {5}, pages = {2433-2447}, doi = {10.1111/1462-2920.15444}, pmid = {33615654}, issn = {1462-2920}, mesh = {Biofilms ; Fungi ; Ophiostoma ; *Pseudomonas putida/genetics ; *Quorum Sensing ; }, abstract = {Interkingdom communication is of particular relevance in polymicrobial biofilms. In this work, the ability of the fungus Ophiostoma piceae to form biofilms individually and in consortium with the bacterium Pseudomonas putida, as well as the effect of fungal and bacterial signal molecules on the architecture of the biofilms was evaluated. Pseudomonas putida KT2440 is able to form biofilms through the secretion of exopolysaccharides and two large extracellular adhesion proteins, LapA and LapF. It has two intercellular signalling systems, one mediated by dodecanoic acid and an orphan LuxR receptor that could participate in the response to AHL-type quorum sensing molecules (QSMs). Furthermore, the dimorphic fungus O. piceae uses farnesol as QSM to control its yeast to hyphae morphological transition. Results show for the first time the ability of this fungus to form biofilms alone and in mixed cultures with the bacterium. Biofilms were induced by bacterial and fungal QSMs. The essential role of LapA-LapF proteins in the architecture of biofilms was corroborated, LapA was induced by farnesol and dodecanol, while LapF by 3-oxo-C6-HSL and 3-oxo-C12-HSL. Our results indicate that fungal signals can induce a transient rise in the levels of the secondary messenger c-di-GMP, which control biofilm formation and architecture.}, } @article {pmid33615511, year = {2021}, author = {Rather, MA and Gupta, K and Bardhan, P and Borah, M and Sarkar, A and Eldiehy, KSH and Bhuyan, S and Mandal, M}, title = {Microbial biofilm: A matter of grave concern for human health and food industry.}, journal = {Journal of basic microbiology}, volume = {61}, number = {5}, pages = {380-395}, doi = {10.1002/jobm.202000678}, pmid = {33615511}, issn = {1521-4028}, support = {BT/PR16149/NER/95/85/2015//Department of Biotechnology, Ministry of Science and Technology/ ; TU/Fin/R/18-19/339//Tezpur University/ ; }, mesh = {Animals ; Aquaculture ; Bacteria/growth & development/*pathogenicity ; Bacterial Infections/microbiology/mortality ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Food Industry/*economics/methods ; Food Microbiology ; Humans ; Meat/microbiology ; Poultry/microbiology ; }, abstract = {Pathogenic microorganisms have adapted different strategies during the course of time to invade host defense mechanisms and overcome the effect of potent antibiotics. The formation of biofilm on both biotic and abiotic surfaces by microorganisms is one such strategy to resist and survive even in presence of antibiotics and other adverse environmental conditions. Biofilm is a safe home of microorganisms embedded within self-produced extracellular polymeric substances comprising of polysaccharides, extracellular proteins, nucleic acid, and water. It is because of this adaptation strategy that pathogenic microorganisms are taking a heavy toll on the health and life of organisms. In this review, we discuss the colonization of pathogenic microorganisms on tissues and medically implanted devices in human beings. We also focus on food spoilage, disease outbreaks, biofilm-associated deaths, burden on economy, and other major concerns of biofilm-forming pathogenic microorganisms in food industries like dairy, poultry, ready-to-eat food, meat, and aquaculture.}, } @article {pmid33615460, year = {2021}, author = {Loss, M and Thompson, KG and Agostinho-Hunt, A and James, GA and Mongodin, EF and Rosenthal, I and Cheng, N and Leung, S and Chien, AL and Kang, S}, title = {Noninflammatory comedones have greater diversity in microbiome and are more prone to biofilm formation than inflammatory lesions of acne vulgaris.}, journal = {International journal of dermatology}, volume = {60}, number = {5}, pages = {589-596}, doi = {10.1111/ijd.15308}, pmid = {33615460}, issn = {1365-4632}, support = {//Provost Young Investigator Fund of the Johns Hopkins Department of Dermatology/ ; //American Acne and Rosacea Society/ ; //University of Maryland School of Medicine/ ; }, mesh = {*Acne Vulgaris ; Biofilms ; Humans ; *Microbiota ; Propionibacterium acnes ; RNA, Ribosomal, 16S/genetics ; }, abstract = {BACKGROUND: The ability of Cutibacterium acnes strains to form biofilms has been correlated with their virulence.

OBJECTIVE: This study examined biofilm and skin microbiota in acne patients in order to understand their role in the development of acne lesions.

METHODS: Thin sections of punch biopsy specimens of (i) uninflamed comedones, (ii) inflammatory lesions, and (iii) uninvolved adjacent skin of acne patients were examined. Epiflourescence and confocal laser scanning microscopy were used for biofilm detection, and pyrosequencing with taxonomic classification of 16s rRNA gene amplicons was used for microbiota analysis.

RESULTS: Of the 39 skin specimens from patients with mild-moderate acne (n = 13) that were studied, nine (23%) contained biofilm. Among these specimens, biofilm was most frequently detected in comedones (55.6%) and less frequently in inflammatory papules (22.2%) and uninvolved skin (22.2%). Comedones demonstrated the highest mean alpha diversity of all the lesion subtypes. The relative abundance of Staphylococcus was significantly higher in comedones (11.400% ± 12.242%) compared to uninvolved skin (0.073% ± 0.185%, P = 0.024).

CONCLUSIONS: The microenvironment of the comedone differs from that of inflammatory lesions and unaffected skin. The increased frequency of biofilm in comedones may account for the lack of host inflammatory response to these lesions.}, } @article {pmid33610507, year = {2022}, author = {Chen, CL and Dudek, A and Liang, YH and Janapatla, RP and Lee, HY and Hsu, L and Kuo, HY and Chiu, CH}, title = {d-mannose-sensitive pilus of Acinetobacter baumannii is linked to biofilm formation and adherence onto respiratory tract epithelial cells.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {55}, number = {1}, pages = {69-79}, doi = {10.1016/j.jmii.2021.01.008}, pmid = {33610507}, issn = {1995-9133}, mesh = {*Acinetobacter baumannii ; Biofilms ; Epithelial Cells ; Escherichia coli/genetics ; Humans ; Mannose ; Respiratory System ; }, abstract = {BACKGROUND/PURPOSE: Acinetobacter baumannii is an important nosocomial pathogen. To better understand the role of CsuA/BABCDE pilus of A. baumannii in virulence, bacterial biofilm formation, adherence and carbohydrate-mediated inhibition were conducted.

METHODS: CsuA/BABCDE pilus-producing (abbreviated Csu pilus) operon of A. baumannii ATCC17978 was cloned for analysis of biofilm formation on an abiotic plastic plate, bacterial adherence to respiratory epithelial human A549 cells and carbohydrate-mediated inhibition. The carbohydrates used for inhibition of biofilm formation and adherence to A549 cells included monosaccharides, pyranosides, and mannose-polymers.

RESULTS: The Csu pilus of A. baumannii ATCC17978 was cloned and expressed into a non-pilus-producing Escherichia coli JM109, and was knocked out as well. The recombinant Csu (rCsu) pilus on E. coli JM109/rCsu pilus-producing clone observed by both electro-microscopy and atomic force microscopy showed abundant, while Csu-knockout A. baumannii ATCC17978 mutant appeared less or no pilus production. The E. coli JM109/rCsu pilus-producing clone significantly increased biofilm formation and adherence to A549 cells; however, the Csu-knockout mutant dramatically lost biofilm-making ability but, in contrast, increased adherence. Moreover, both of biofilm formation and adherence could be significantly inhibited by d-mannose and methyl-α-d-mannopyranoside in Csu pilus-producing E. coli JM109, whereas in A. baumannii ATCC17978, high concentration of carbohydrates was required for the inhibition, suggesting that Csu pilus is sensitive to d-mannose.

CONCLUSION: This is the first study confirming that Csu pilus of A. baumannii belongs to mannose-sensitive type 1 pilus family and contributes to biofilm formation and bacterial adherence to human epithelial cells.}, } @article {pmid33609862, year = {2021}, author = {Miao, L and Gao, Y and Adyel, TM and Huo, Z and Liu, Z and Wu, J and Hou, J}, title = {Effects of biofilm colonization on the sinking of microplastics in three freshwater environments.}, journal = {Journal of hazardous materials}, volume = {413}, number = {}, pages = {125370}, doi = {10.1016/j.jhazmat.2021.125370}, pmid = {33609862}, issn = {1873-3336}, mesh = {Biofilms ; China ; Ecosystem ; Environmental Monitoring ; *Microplastics ; Plastics ; *Water Pollutants, Chemical/analysis ; }, abstract = {Microplastics (MPs) have frequently been detected in freshwater environments, and there is growing concern about their ecological effects, especially the influence of the "plastisphere" on the freshwater ecosystems. The colonization of microbes on MPs would significantly alter their transport behavior, i.e., buoyancy, in fresh water. In this research, we studied the effects of biofilm colonization on the sinking and floating of three MPs, i.e., polyethylene terephthalate (PET), polypropylene (PP), and polyvinyl chloride (PVC), after 44 days of incubation in three freshwater systems (the Niushoushan River, the Qinhuai River, and East Lake) in China. The results showed that the biofilms attached to the three MPs contained different biomass and chlorophyll-a levels were related to water environmental conditions and physicochemical properties of MPs, based on redundancy analysis. Generally, PET and PVC sinking, with density higher than water, tended to increase after biofilm formation. Thereafter, the settling velocity of biofouled PET and PVC squares became faster than that of the virgin ones. In summary, our study suggested that biofouling does affect the sinking of MPs in fresh water and consequently influences the transport behavior and the distribution characteristics of MPs in freshwater environments, and this issue deserves more scientific attention.}, } @article {pmid33609163, year = {2021}, author = {Shatila, F and Yaşa, İ and Yalçın, HT}, title = {Biofilm Formation by Salmonella enterica Strains.}, journal = {Current microbiology}, volume = {78}, number = {4}, pages = {1150-1158}, pmid = {33609163}, issn = {1432-0991}, support = {2017-FEN-038//Scientific Research Unit of Ege University/ ; }, mesh = {Biofilms ; *Salmonella enterica ; Salmonella enteritidis ; Sodium Chloride ; Temperature ; }, abstract = {Biofilm formation by five different Salmonella enterica strains was assessed qualitatively and quantitatively under different incubation conditions. The strains exhibited different adherence abilities to test tubes. The isolates revealed Red Dry and Rough (RDAR) and Brown Dry and Rough (BDAR) morphotypes when cultured on Congo Red Agar (CRA). The pellicles formed by the tested strains ranged from strong to fragile when incubated in LB without NaCl at 27 °C. Smooth and White (SAW) morphotype on CRA and very weak pellicles were observed when the bacterial strains were incubated at 37 °C. The effect of temperature and media on biofilm formation by the tested strains was significant. Among the five Salmonella isolates, S. enteritidis TM 6 and S. enteritidis TM 68 formed strong biofilms when incubated in LB without NaCl at 27 °C for 24 h and consequently selected to be analysed under scanning electron microscope (SEM). Scanning electron micrographs revealed that S. enteritidis TM 6 formed more complex colonies when compared to those formed by S. enteritidis TM 68. As far as we know, this is the first study that provides quantitative and qualitative data for 5 Salmonella enterica isolates in different media mimicking four different nutritional conditions at two different temperatures after 24 and 48 h. The strains included two serovars S. bredeney and S. anatum, which are rarely accounted for. Additionally, the studies that described S. enteritidis biofilms under SEM are extremely limited, which makes it among the first comprehensive studies that screened for S. enteritidis biofilms.}, } @article {pmid33608902, year = {2021}, author = {Zuo, XS and Liu, Y and Cai, X and Zhan, L and Hu, K}, title = {Association of different Candida species with catheter-related candidemia, and the potential antifungal treatments against their adhesion properties and biofilm-forming capabilities.}, journal = {Journal of clinical laboratory analysis}, volume = {35}, number = {4}, pages = {e23738}, pmid = {33608902}, issn = {1098-2825}, support = {2020YFC0845100//National Key Research and Development Plan for the Emergency Management of Novel Coronavirus Pneumonia/ ; 81801959//National Science Foundation of China/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects ; *Candida/drug effects/pathogenicity/physiology ; Candidemia/*microbiology ; Catheter-Related Infections/*microbiology ; Cell Adhesion/*drug effects ; Humans ; }, abstract = {BACKGROUND: To compare the adhesion properties and biofilm-forming capabilities of 27 Candida isolates obtained from catheter-related candidemia patients and to evaluate the inhibitory effects of antifungal agents on different Candida species.

MATERIAL AND METHODS: Seven C. albicans, six C. parapsilosis, five C. guilliermondii, five C. tropicalis, and four C. glabrata clinical isolates were investigated. We quantified the adherence of these Candida species by flow cytometric method and evaluated the formation of biofilms by XTT reduction and crystal violet methods. Actions of micafungin (MF), fluconazole (FZ), and N-acetylcysteine (NAC) on the adhesion and biofilm formation of different Candida species were determined.

RESULTS: Non-albicans Candida species were demonstrated to have stronger adhesion abilities compared with C. albicans. The biofilm-forming capabilities of different Candida species were varied considerably, and the degree of biofilm formation might be affected by different assay approaches. Interestingly, C. parapsilosis displayed the highest biofilm formation abilities, while C. glabrata exhibited the lowest total biomass and metabolic activity. Furthermore, the inhibitory activities of MF, FZ, and NAC on fungal adhesion and biofilm formation were evaluated, and the results indicated that MF could reduce the adhesion ability and biofilm metabolism more significantly (p < 0.05), and its antifungal activity was elevated in a dose-dependent manner.

CONCLUSION: Non-albicans Candida species, especially C. guilliermondii, C. tropicalis, and C. parapsilosis, exhibited higher adhesion ability in catheter-related candidemia patients. However, these Candida species had varied biofilm-forming capabilities. MF tended to have stronger inhibitory effects against both adhesion and biofilm formation of different Candida species.}, } @article {pmid33606569, year = {2021}, author = {Loera-Muro, A and Guerrero-Barrera, A and Tremblay D N, Y and Hathroubi, S and Angulo, C}, title = {Bacterial biofilm-derived antigens: a new strategy for vaccine development against infectious diseases.}, journal = {Expert review of vaccines}, volume = {20}, number = {4}, pages = {385-396}, doi = {10.1080/14760584.2021.1892492}, pmid = {33606569}, issn = {1744-8395}, mesh = {Antigens, Bacterial ; Biofilms ; *Communicable Diseases ; Humans ; *Quorum Sensing ; Vaccine Development ; }, abstract = {INTRODUCTION: Microorganisms can develop into a social organization known as biofilms and these communities can be found in virtually all types of environment on earth. In biofilms, cells grow as multicellular communities held together by a self-produced extracellular matrix. Living within a biofilm allows for the emergence of specific properties for these cells that their planktonic counterparts do not have. Furthermore, biofilms are the cause of several infectious diseases and are frequently inhabited by multi-species. These interactions between microbial species are often critical for the biofilm process. Despite the importance of biofilms in disease, vaccine antigens are typically prepared from bacteria grown as planktonic cells under laboratory conditions. Vaccines based on planktonic bacteria may not provide optimal protection against biofilm-driven infections.

AREAS COVERED: In this review, we will present an overview of biofilm formation, what controls this mode of growth, and recent vaccine development targeting biofilms.

EXPERT OPINION: Previous and ongoing research provides evidence that vaccine formulation with antigens derived from biofilms is a promising approach to prevent infectious diseases and can enhance the protective efficacy of existing vaccines. Therefore, research focusing on the identification of biofilm-derived antigens merits further investigations.}, } @article {pmid33604521, year = {2020}, author = {Rajapakse, S and Giardino, MA and Kulasekara, HD and Darveau, RP and Chang, AM}, title = {An Ayurvedic Herbal Extract Inhibits Streptococcus mutans Biofilm Formation and Disrupts Preformed Biofilms in vitro.}, journal = {Journal of traditional medicine & clinical naturopathy}, volume = {9}, number = {4}, pages = {}, pmid = {33604521}, issn = {2573-4555}, support = {T90 DE021984/DE/NIDCR NIH HHS/United States ; }, abstract = {OBJECTIVE: Sudantha® (SUD), a natural proprietary mixture of herbal extracts that has been incorporated into toothpaste, has been shown in two separate placebo controlled human clinical studies to promote gingival health; and reduce gingival bleeding and plaque formation. However, the herbal based anti-gingivitis mechanisms of Sudantha are not fully understood. The objective of this study was to determine the effect of Sudantha on dental plaque biofilms by investigating its effect on mono-culture biofilms of a primary colonizer, Streptococcus mutans, in vitro.

RESULTS: This study found that SUD contributes to the maintenance of oral health through the inhibition of S. mutans biofilm formation. In addition, SUD disrupted preformed S. mutans biofilms after exposure to SUD for 4 hours. Together, this pilot data suggests the inhibition of S. mutans biofilm formation and disruption represents one potential mechanism by which the herbal extract is able to reduce the oral bacterial biofilm resulting in its effective against gingivitis and its potential use in countering biofilm associated oral disease.}, } @article {pmid33604383, year = {2021}, author = {Rostamifar, S and Azad, A and Bazrafkan, A and Modaresi, F and Atashpour, S and Jahromi, ZK}, title = {New Strategy of Reducing Biofilm Forming Bacteria in Oral Cavity by Bismuth Nanoparticles.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {6695692}, pmid = {33604383}, issn = {2314-6141}, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/*pharmacology ; Bacteria/drug effects/genetics ; Biofilms/*drug effects ; Bismuth/*pharmacology ; Chlorhexidine/pharmacology ; Cross-Sectional Studies ; Drug Resistance, Bacterial/drug effects ; Female ; Humans ; Iran ; Male ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Middle Aged ; Mouth/*microbiology ; Young Adult ; }, abstract = {OBJECTIVE: Enterococcus faecalis and Streptococcus salivarius are the most important species in dental decay and producing biofilm. Treatment with chlorhexidine 2% mouthwash for 7 days is the best way to eliminate these bacteria. However, due to the ability of these bacteria to survive in harsh environments, increasing emergence of bacterial resistance against available antibiotics, and favorable properties of nanoparticles including broad spectrum antimicrobial activity and lower toxicity, we decided to evaluate reducing biofilm forming bacteria in oral cavity by bismuth nanoparticles.

MATERIALS AND METHODS: This was a cross-sectional study of 40 samples isolated from the patients visiting dental clinics in Shiraz in 2019. Samples, which showed growth, were cultured on blood agar plates and incubated for the PCR procedure. Nanoparticle powder was dissolved in high-purity water, and the final concentration of bismuth nanoparticles (BiNPs) was measured with a spectrophotometer. Minimum inhibitory concentration (MIC) of BiNPs against E. faecalis and S. salivarius was determined by the microbroth dilution method according to methods for antimicrobial susceptibility tests. Also, bactericidal assays were conducted in a Mueller-Hinton broth medium and reported as the concentration of BiNPs that reduced the viable bacterial count by 99.9%. Statistical analysis was carried out using SPSS 21 and one-way analysis of variance, and P values less than 0.05 were considered significant.

RESULTS: MICs of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 2.5 and 5 μg/ml, respectively. Minimum bactericidal concentrations (MBC) of BiNP suspension against Streptococcus salivarius and Enterococcus faecalis were 5 and 10 μg/ml, respectively. Antibacterial activity of BiNPs was compared with chlorhexidine 2%. MICs of BiNPs against Streptococcus salivarius and Enterococcus faecalis were one-twentieth less than those of chlorhexidine. MBC of BiNPs against both pathogens was one-tenth less than those of chlorhexidine.

CONCLUSION: BiNPs were more effective than chlorhexidine, and MIC and MBC of bismuth nanoparticles are lower than those of chlorhexidine.}, } @article {pmid33604308, year = {2020}, author = {Harrell, JE and Hahn, MM and D'Souza, SJ and Vasicek, EM and Sandala, JL and Gunn, JS and McLachlan, JB}, title = {Salmonella Biofilm Formation, Chronic Infection, and Immunity Within the Intestine and Hepatobiliary Tract.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {624622}, pmid = {33604308}, issn = {2235-2988}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; R21 AI153752/AI/NIAID NIH HHS/United States ; R21 AI156328/AI/NIAID NIH HHS/United States ; U01 AI124289/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms ; Humans ; Intestines ; *Salmonella enterica ; *Salmonella typhi ; Salmonella typhimurium ; }, abstract = {Within the species of Salmonella enterica, there is significant diversity represented among the numerous subspecies and serovars. Collectively, these account for microbes with variable host ranges, from common plant and animal colonizers to extremely pathogenic and human-specific serovars. Despite these differences, many Salmonella species find commonality in the ability to form biofilms and the ability to cause acute, latent, or chronic disease. The exact outcome of infection depends on many factors such as the growth state of Salmonella, the environmental conditions encountered at the time of infection, as well as the infected host and immune response elicited. Here, we review the numerous biofilm lifestyles of Salmonella (on biotic and abiotic surfaces) and how the production of extracellular polymeric substances not only enhances long-term persistence outside the host but also is an essential function in chronic human infections. Furthermore, careful consideration is made for the events during initial infection that allow for gut transcytosis which, in conjunction with host immune functions, often determine the progression of disease. Both typhoidal and non-typhoidal salmonellae can cause chronic and/or secondary infections, thus the adaptive immune responses to both types of bacteria are discussed with particular attention to the differences between Salmonella Typhi, Salmonella Typhimurium, and invasive non-typhoidal Salmonella that can result in differential immune responses. Finally, while strides have been made in our understanding of immunity to Salmonella in the lymphoid organs, fewer definitive studies exist for intestinal and hepatobiliary immunity. By examining our current knowledge and what remains to be determined, we provide insight into new directions in the field of Salmonella immunity, particularly as it relates to chronic infection.}, } @article {pmid33597330, year = {2021}, author = {Nishiuchi, Y}, title = {Ultrastructure of the Mycobacterium avium subsp. hominissuis Biofilm.}, journal = {Microbes and environments}, volume = {36}, number = {1}, pages = {}, pmid = {33597330}, issn = {1347-4405}, mesh = {*Biofilms ; Humans ; Microscopy, Electron, Scanning ; Mycobacterium/genetics/*physiology/*ultrastructure ; Mycobacterium Infections/microbiology ; }, abstract = {Mycobacterium avium subsp. hominissuis (MAH) is one of the most common nontuberculous mycobacterial pathogens responsible for chronic lung disease in humans. It is widely distributed in biofilms in natural and living environments. It is considered to be transmitted from the environment. Despite its importance in public health, the ultrastructure of the MAH biofilm remains largely unknown. The ultrastructure of a MAH-containing multispecies biofilm that formed naturally in a bathtub inlet was herein reported along with those of monoculture biofilms developed from microcolonies and pellicles formed in the laboratory. Scanning electron microscopy revealed an essentially multilayered bathtub biofilm that was packed with cocci and short and long rods connected by an extracellular matrix (ECM). Scattered mycobacterium-like rod-shaped cells were observed around biofilm chunks. The MAH monoculture biofilms that developed from microcolonies in vitro exhibited an assembly of flat layers covered with thin film-like ECM membranes. Numerous small bacterial cells (0.76±0.19‍ ‍μm in length) were observed, but not embedded in ECM. A glycopeptidolipid-deficient strain did not develop the layered ECM membrane architecture, suggesting its essential role in the development of biofilms. The pellicle biofilm also consisted of flat layered cells covered with an ECM membrane and small cells. MAH alone generated a flat layered biofilm covered with an ECM membrane. This unique structure may be suitable for resistance to water flow and disinfectants and the exclusion of fast-growing competitors, and small cells in biofilms may contribute to the formation and transmission of bioaerosols.}, } @article {pmid33596813, year = {2021}, author = {Dier-Pereira, AP and Trevizani Thihara, IR and Duarte, FC and da Silva, RS and Santos, JP and Tavares, ER and de Oliveira, CF and Pinge-Filho, P and Kerbauy, G and Perugini, MRE and Yamauchi, LM and Yamada-Ogatta, SF}, title = {Methicillin-Resistant Staphylococcus haemolyticus Displaying Reduced Susceptibility to Vancomycin and High Biofilm-Forming Ability.}, journal = {Infectious disorders drug targets}, volume = {21}, number = {7}, pages = {e160921191517}, doi = {10.2174/1871526521666210217151807}, pmid = {33596813}, issn = {2212-3989}, support = {01//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; Methicillin Resistance/genetics ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; Staphylococcus haemolyticus/genetics ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: Staphylococcus haemolyticus is one of the most frequently coagulasenegative staphylococci isolated from healthcare-associated infections, mainly those related to implanted medical devices.

OBJECTIVES: This study aimed to determine the antimicrobial susceptibility profile and biofilm forming capacity of S. haemolyticus isolated from bloodstream infections.

METHODS: A total of 40 S. haemolyticus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), antimicrobial susceptibility profile, SCCmec typing, ability to form biofilm on abiotic surface and occurrence of putative genes related to biofilm formation.

RESULTS: One S. haemolyticus was susceptible to all antimicrobials. The other isolates (n=39) were resistant to cefoxitin; and among them 34 (87.2%) harbored the mecA gene into the SCCmec type I (5.9%), type III (29.4%), type IV (5.9%) and type V (20.6%); and 38.2% isolates were designated as NT. Apart from cefoxitin, 94.9% of the isolates were resistant to at least four antimicrobial classes, and 32.5% displayed minimal inhibitory concentration (MIC) values higher than 4.0 μg/mL for vancomycin. All isolates formed biofilm on polystyrene surface and were classified as strong biofilm-producers, except for one isolate. All isolates were negative for icaA gene, and the prevalence of the other genes was as follows: atl, 100%; fbp, 92.5%; aap, 90.0%; and bap, 20.0%.

CONCLUSION: This study reports a high prevalence of methicillin-resistant S. haemolyticus displaying decreased susceptibility to vancomycin with the ability to form strong biofilms on abiotic surface. The results support the importance of controlling the adequate use of antimicrobials for the treatment of staphylococcal infections.}, } @article {pmid33596477, year = {2021}, author = {Moghaddam-Taaheri, P and Leissa, JA and Eppler, HB and Jewell, CM and Karlsson, AJ}, title = {Histatin 5 variant reduces Candida albicans biofilm viability and inhibits biofilm formation.}, journal = {Fungal genetics and biology : FG & B}, volume = {149}, number = {}, pages = {103529}, pmid = {33596477}, issn = {1096-0937}, support = {I01 BX003690/BX/BLRD VA/United States ; R01 EB027143/EB/NIBIB NIH HHS/United States ; R03 DE029270/DE/NIDCR NIH HHS/United States ; T32 GM080201/GM/NIGMS NIH HHS/United States ; }, mesh = {Antifungal Agents/pharmacology ; Antimicrobial Cationic Peptides/chemistry ; Aspartic Acid Proteases/genetics/metabolism ; Biofilms/growth & development ; Candida albicans/genetics/*growth & development/metabolism ; Histatins/*genetics/metabolism/physiology ; Humans ; Proteolysis ; }, abstract = {Candida albicans is a commensal organism and opportunistic pathogen that can form biofilms that colonize surfaces of medical devices, such as implants, catheters, and dentures. Compared to planktonic C. albicans cells, cells in biofilms exhibit increased resistance to treatment. Histatin 5 (Hst-5) is an antimicrobial peptide that is natively secreted by human salivary glands and has strong antifungal activity against C. albicans. However, C. albicans produces secreted aspartic proteases (Saps) that can cleave and inactivate Hst-5, limiting its antifungal properties. We previously showed that residue substitutions K11R and K17R within Hst-5 improve its antifungal activity and prevent proteolytic degradation by Saps when treating planktonic C. albicans. Here, we investigated the use of the K11R-K17R peptide as an alternative therapeutic against C. albicans biofilms by assessing its ability to reduce viability of pre-formed biofilms and to inhibit the formation of biofilms and showed that K11R-K17R had improved activity compared to Hst-5. Based on these results, we incorporated K11R-K17R and Hst-5 into polyelectrolyte multilayer (PEM) surface coatings and demonstrated that films functionalized with K11R-K17R reduced the formation of C. albicans biofilms. Our results demonstrate the therapeutic potential of the K11R-K17R Hst-5 variant in preventing and treating biofilms.}, } @article {pmid33594973, year = {2021}, author = {Arjes, HA and Willis, L and Gui, H and Xiao, Y and Peters, J and Gross, C and Huang, KC}, title = {Three-dimensional biofilm colony growth supports a mutualism involving matrix and nutrient sharing.}, journal = {eLife}, volume = {10}, number = {}, pages = {}, pmid = {33594973}, issn = {2050-084X}, support = {R35 GM118061/GM/NIGMS NIH HHS/United States ; K22 AI137122/AI/NIAID NIH HHS/United States ; }, mesh = {Alanine Racemase/genetics/metabolism ; Bacillus subtilis/genetics/*growth & development ; Biofilms/*growth & development ; Clustered Regularly Interspaced Short Palindromic Repeats ; Culture Media ; Gene Expression Regulation, Bacterial ; Gene Knockdown Techniques ; *Symbiosis ; }, abstract = {Life in a three-dimensional biofilm is typical for many bacteria, yet little is known about how strains interact in this context. Here, we created essential gene CRISPR interference knockdown libraries in biofilm-forming Bacillus subtilis and measured competitive fitness during colony co-culture with wild type. Partial knockdown of some translation-related genes reduced growth rates and led to out-competition. Media composition led some knockdowns to compete differentially as biofilm versus non-biofilm colonies. Cells depleted for the alanine racemase AlrA died in monoculture but survived in a biofilm colony co-culture via nutrient sharing. Rescue was enhanced in biofilm colony co-culture with a matrix-deficient parent due to a mutualism involving nutrient and matrix sharing. We identified several examples of mutualism involving matrix sharing that occurred in three-dimensional biofilm colonies but not when cultured in two dimensions. Thus, growth in a three-dimensional colony can promote genetic diversity through sharing of secreted factors and may drive evolution of mutualistic behavior.}, } @article {pmid33593969, year = {2021}, author = {Kowalski, CH and Morelli, KA and Stajich, JE and Nadell, CD and Cramer, RA}, title = {A Heterogeneously Expressed Gene Family Modulates the Biofilm Architecture and Hypoxic Growth of Aspergillus fumigatus.}, journal = {mBio}, volume = {12}, number = {1}, pages = {}, pmid = {33593969}, issn = {2150-7511}, support = {R01 AI130128/AI/NIAID NIH HHS/United States ; P20 GM113132/GM/NIGMS NIH HHS/United States ; R01 AI146121/AI/NIAID NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; F31 AI138354/AI/NIAID NIH HHS/United States ; T32 HL134598/HL/NHLBI NIH HHS/United States ; }, mesh = {Anaerobiosis ; Aspergillus fumigatus/*genetics/*physiology ; Biofilms/*growth & development ; Fungal Proteins/*genetics ; *Gene Expression ; Hyphae/growth & development ; *Multigene Family ; Oxygen/analysis ; Spores, Fungal/growth & development ; }, abstract = {The genus Aspergillus encompasses human pathogens such as Aspergillus fumigatus and industrial powerhouses such as Aspergillus niger In both cases, Aspergillus biofilms have consequences for infection outcomes and yields of economically important products. However, the molecular components influencing filamentous fungal biofilm development, structure, and function remain ill defined. Macroscopic colony morphology is an indicator of underlying biofilm architecture and fungal physiology. A hypoxia-locked colony morphotype of A. fumigatus has abundant colony furrows that coincide with a reduction in vertically oriented hyphae within biofilms and increased low oxygen growth and virulence. Investigation of this morphotype has led to the identification of the causative gene, biofilm architecture factor A (bafA), a small cryptic open reading frame within a subtelomeric gene cluster. BafA is sufficient to induce the hypoxia-locked colony morphology and biofilm architecture in A. fumigatus Analysis across a large population of A. fumigatus isolates identified a larger family of baf genes, all of which have the capacity to modulate hyphal architecture, biofilm development, and hypoxic growth. Furthermore, introduction of A. fumigatusbafA into A. niger is sufficient to generate the hypoxia-locked colony morphology, biofilm architecture, and increased hypoxic growth. Together, these data indicate the potential broad impacts of this previously uncharacterized family of small genes to modulate biofilm architecture and function in clinical and industrial settings.IMPORTANCE The manipulation of microbial biofilms in industrial and clinical applications remains a difficult task. The problem is particularly acute with regard to filamentous fungal biofilms for which molecular mechanisms of biofilm formation, maintenance, and function are only just being elucidated. Here, we describe a family of small genes heterogeneously expressed across Aspergillus fumigatus strains that are capable of modifying colony biofilm morphology and microscopic hyphal architecture. Specifically, these genes are implicated in the formation of a hypoxia-locked colony morphotype that is associated with increased virulence of A. fumigatus Synthetic introduction of these gene family members, here referred to as biofilm architecture factors, in both A. fumigatus and A. niger additionally modulates low oxygen growth and surface adherence. Thus, these genes are candidates for genetic manipulation of biofilm development in aspergilli.}, } @article {pmid33593965, year = {2021}, author = {Sun, W and Yu, Y and Chen, J and Yu, B and Chen, T and Ying, H and Zhou, S and Ouyang, P and Liu, D and Chen, Y}, title = {Light Signaling Regulates Aspergillus niger Biofilm Formation by Affecting Melanin and Extracellular Polysaccharide Biosynthesis.}, journal = {mBio}, volume = {12}, number = {1}, pages = {}, pmid = {33593965}, issn = {2150-7511}, mesh = {Aspergillus niger/*genetics/growth & development ; Biofilms/*growth & development ; Carbohydrate Metabolism ; Fungal Polysaccharides/*biosynthesis/genetics/radiation effects ; Fungal Proteins/metabolism ; *Gene Expression Regulation, Fungal ; *Light ; Melanins/*biosynthesis ; Signal Transduction/*genetics/radiation effects ; Transcription Factors/metabolism ; }, abstract = {Light is an important signal source in nature, which regulates the physiological cycle, morphogenetic pathways, and secondary metabolites of fungi. As an external pressure on Aspergillus niger, light signaling transmits stress signals into the cell via the mitogen-activated protein kinase (MAPK) signaling pathway. Studying the effect of light on the biofilm of A. niger will provide a theoretical basis for light in the cultivation of filamentous fungi and industrial applications. Here, the characterization of A. niger biofilm under different light intensities confirmed the effects of light signaling. Our results indicated that A. niger intensely accumulated protective mycelial melanin under light illumination. We also discovered that the RlmA transcription factor in the MAPK signaling pathway is activated by light signaling to promote the synthesis of melanin, chitin, and other exopolysaccharides. However, the importance of melanin to A. niger biofilm is rarely reported; therefore, we knocked out key genes of the melanin biosynthetic pathway-Abr1 and Ayg1 Changes in hydrophobicity and electrostatic forces resulted in the decrease of biofilm caused by the decrease of melanin in mutants.IMPORTANCE As an important industrial filamentous fungus, Aspergillus niger can perceive light. The link between light signaling and A. niger biofilm is worthy of further study since reports are lacking in this area. This study found that light signaling promotes biofilm production in A. niger, wherein melanin plays an important role. It was further discovered that the RlmA transcription factor in the mitogen-activated protein kinase (MAPK) signaling pathway was mediated by light signaling to promote the synthesis of melanin and extracellular polysaccharides. These findings set the stage for light signal regulation of biofilm in filamentous fungi and provide a theoretical basis for the development of a new light-controlled biofilm method to improve biofilm-based industrial fermentation.}, } @article {pmid33592455, year = {2021}, author = {Rajasekar, V and Darne, P and Prabhune, A and Kao, RYT and Solomon, AP and Ramage, G and Samaranayake, L and Neelakantan, P}, title = {A curcumin-sophorolipid nanocomplex inhibits Candida albicans filamentation and biofilm development.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {200}, number = {}, pages = {111617}, doi = {10.1016/j.colsurfb.2021.111617}, pmid = {33592455}, issn = {1873-4367}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; *Curcumin/pharmacology ; Humans ; Hyphae ; Oleic Acids ; }, abstract = {Candida albicans is an opportunistic fungal pathogen that is highly resistant to contemporary antifungals, due to their biofilm lifestyle. The ability of C. albicans to invade human tissues is due to its filamentation. Therefore, inhibition of biofilms and filamentation of the yeast are high value targets to develop the next-generation antifungals. Curcumin (CU) is a natural polyphenol with excellent pharmacological attributes, but limitations such as poor solubility, acid, and enzyme tolerance have impeded its practical utility. Sophorolipids (SL) are biologically-derived surfactants that serve as efficient carriers of hydrophobic molecules such as curcumin into biofilms. Here, we synthesised a curcumin-sophorolipid nanocomplex (CUSL), and comprehensively evaluated its effects on C. albicans biofilms and filamentation. Our results demonstrated that sub-inhibitory concentration of CUSL (9.37 μg/mL) significantly inhibited fungal adhesion to substrates, and subsequent biofilm development, maturation, and filamentation. This effect was associated with significant downregulation of a select group of biofilm, adhesins, and hyphal regulatory genes. In conclusion, the curcumin-sophorolipid nanocomplex is a potent inhibitor of the two major virulence attributes of C. albicans, biofilm formation and filamentation, thus highlighting its promise as a putative anti-fungal agent with biofilm penetrative potential.}, } @article {pmid33592330, year = {2021}, author = {Cardoso, A and Fernandes, JT and Bussadori, SK and Horliana, ACRT and Fernandes, KPS and Gonçalves, MLL and Motta, LJ}, title = {Use of optical fluorescence for the diagnosis of dental biofilm in young permanent molars - A case series.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {34}, number = {}, pages = {102216}, doi = {10.1016/j.pdpdt.2021.102216}, pmid = {33592330}, issn = {1873-1597}, mesh = {Biofilms ; Brazil ; Child ; Fluorescence ; Humans ; Molar ; *Photochemotherapy/methods ; Photosensitizing Agents ; }, abstract = {BACKGROUND: Fluorescence appears clearly in oral biofilm in red tones, showing the presence of microorganisms in regions where there is biofilm accumulation. This study aims to evaluate the applicability and effectiveness of the diagnosis of oral biofilm with the optical fluorescence technique using the EVINCE (Evidenciador Clínico - MMOptics, São Carlos, SP, Brazil) equipment. Furthermore, to compare the efficacy of the optical fluorescence diagnostic method with the traditional method of clinical disclosure of Fuchsin-based dye biofilm and to observe their combined use.

METHODS: Sixteen children, aged between 7 and 12, were included in this case series, following the Oral Hygiene Index - Simplificated (OHI-S) evaluation. They were evaluated by 3 different professionals. The 1 st evaluator checked the OHI-S observing only with EVINCE. In the second stage, a 2nd evaluator performed the traditional disclosure technique with Fucsina, and finally a 3rd evaluator who observed with EVINCE the teeth previously stained in stage 2, combining the two methods. Descriptive analysis of the variables was performed and comparative tests of repeated measures to evaluate differences between the results of the three evaluation methodologies.

RESULTS: There is no significant difference between the observation made only with EVINCE and with the traditional methodology of plaque disclosure. However, there is a difference when the two techniques are used in the third evaluation moment, showing that the combination could provide better results.

CONCLUSIONS: The association of both the conventional method and the use of EVINCE showed a very satisfactory result for the diagnosis of the presence of biofilm.}, } @article {pmid33592026, year = {2021}, author = {Michael, H and Paim, FC and Miyazaki, A and Langel, SN and Fischer, DD and Chepngeno, J and Goodman, SD and Rajashekara, G and Saif, LJ and Vlasova, AN}, title = {Escherichia coli Nissle 1917 administered as a dextranomar microsphere biofilm enhances immune responses against human rotavirus in a neonatal malnourished pig model colonized with human infant fecal microbiota.}, journal = {PloS one}, volume = {16}, number = {2}, pages = {e0246193}, pmid = {33592026}, issn = {1932-6203}, support = {T32 AI007392/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Animals, Newborn ; Antibodies, Viral/immunology ; B-Lymphocytes/immunology ; *Biofilms ; Dextrans/*chemistry ; Disease Models, Animal ; Escherichia coli/*physiology ; Feces/*microbiology ; Malnutrition/microbiology/*virology ; *Microbiota ; Microspheres ; RNA, Messenger/genetics ; Rotavirus/*immunology/physiology ; SOX9 Transcription Factor/genetics ; Swine ; Up-Regulation ; }, abstract = {Human rotavirus (HRV) is a leading cause of diarrhea in children. It causes significant morbidity and mortality, especially in low- and middle-income countries (LMICs), where HRV vaccine efficacy is low. The probiotic Escherichia coli Nissle (EcN) 1917 has been widely used in the treatment of enteric diseases in humans. However, repeated doses of EcN are required to achieve maximum beneficial effects. Administration of EcN on a microsphere biofilm could increase probiotic stability and persistence, thus maximizing health benefits without repeated administrations. Our aim was to investigate immune enhancement by the probiotic EcN adhered to a dextranomar microsphere biofilm (EcN biofilm) in a neonatal, malnourished piglet model transplanted with human infant fecal microbiota (HIFM) and infected with rotavirus. To create malnourishment, pigs were fed a reduced amount of bovine milk. Decreased HRV fecal shedding and protection from diarrhea were evident in the EcN biofilm treated piglets compared with EcN suspension and control groups. Moreover, EcN biofilm treatment enhanced natural killer cell activity in blood mononuclear cells (MNCs). Increased frequencies of activated plasmacytoid dendritic cells (pDC) in systemic and intestinal tissues and activated conventional dendritic cells (cDC) in blood and duodenum were also observed in EcN biofilm as compared with EcN suspension treated pigs. Furthermore, EcN biofilm treated pigs had increased frequencies of systemic activated and resting/memory antibody forming B cells and IgA+ B cells in the systemic tissues. Similarly, the mean numbers of systemic and intestinal HRV-specific IgA antibody secreting cells (ASCs), as well as HRV-specific IgA antibody titers in serum and small intestinal contents, were increased in the EcN biofilm treated group. In summary EcN biofilm enhanced innate and B cell immune responses after HRV infection and ameliorated diarrhea following HRV challenge in a malnourished, HIFM pig model.}, } @article {pmid33589302, year = {2021}, author = {Falkinham, JO}, title = {Corrigendum to "Disinfection and cleaning of heater-cooler units: suspension- and biofilm-killing" [Journal of Hospital Infection 105 (2020) 552-557].}, journal = {The Journal of hospital infection}, volume = {110}, number = {}, pages = {211}, doi = {10.1016/j.jhin.2021.01.002}, pmid = {33589302}, issn = {1532-2939}, } @article {pmid33588990, year = {2021}, author = {Del Peso Santos, T and Alvarez, L and Sit, B and Irazoki, O and Blake, J and Warner, BR and Warr, AR and Bala, A and Benes, V and Waldor, MK and Fredrick, K and Cava, F}, title = {BipA exerts temperature-dependent translational control of biofilm-associated colony morphology in Vibrio cholerae.}, journal = {eLife}, volume = {10}, number = {}, pages = {}, pmid = {33588990}, issn = {2050-084X}, support = {R01 AI042347/AI/NIAID NIH HHS/United States ; R01 GM072528/GM/NIGMS NIH HHS/United States ; T32 AI132120/AI/NIAID NIH HHS/United States ; T32 AI-132120/NH/NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms/growth & development ; GTP Phosphohydrolases/*genetics/metabolism ; Phenotype ; Temperature ; Vibrio cholerae/genetics/*physiology ; }, abstract = {Adaptation to shifting temperatures is crucial for the survival of the bacterial pathogen Vibrio cholerae. Here, we show that colony rugosity, a biofilm-associated phenotype, is regulated by temperature in V. cholerae strains that naturally lack the master biofilm transcriptional regulator HapR. Using transposon-insertion mutagenesis, we found the V. cholerae ortholog of BipA, a conserved ribosome-associated GTPase, is critical for this temperature-dependent phenomenon. Proteomic analyses revealed that loss of BipA alters the synthesis of >300 proteins in V. cholerae at 22°C, increasing the production of biofilm-related proteins including the key transcriptional activators VpsR and VpsT, as well as proteins important for diverse cellular processes. At low temperatures, BipA protein levels increase and are required for optimal ribosome assembly in V. cholerae, suggesting that control of BipA abundance is a mechanism by which bacteria can remodel their proteomes. Our study reveals a remarkable new facet of V. cholerae's complex biofilm regulatory network.}, } @article {pmid33588850, year = {2021}, author = {Shadkam, S and Goli, HR and Mirzaei, B and Gholami, M and Ahanjan, M}, title = {Correlation between antimicrobial resistance and biofilm formation capability among Klebsiella pneumoniae strains isolated from hospitalized patients in Iran.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {20}, number = {1}, pages = {13}, pmid = {33588850}, issn = {1476-0711}, support = {10320//Mazandaran University of Medical Sciences/ ; }, mesh = {*Biofilms ; Cross Infection/*microbiology ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial ; Hospitalization ; Humans ; Klebsiella pneumoniae/*drug effects/genetics/isolation & purification/physiology ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is a common cause of nosocomial infections. Antibiotic resistance and ability to form biofilm, as two key virulence factors of K. pneumoniae, are involved in the persistence of infections. The purpose of this study was to investigate the correlation between antimicrobial resistance and biofilm formation capability among K. pneumoniae strains isolated from hospitalized patients in Iran.

METHODS: Over a 10-month period, a total of 100 non-duplicate K. pneumoniae strains were collected. Antibiotic susceptibility was determined by Kirby-Bauer disk diffusion method according to CLSI. Biofilm production was assessed by tissue culture plate method. Finally, polymerase chain reaction was conducted to detect four families of carbapenemase: blaIMP, blaVIM, blaNDM, blaOXA-48; biofilm formation associated genes: treC, wza, luxS; and K. pneumoniae confirming gene: rpoB.

RESULTS: Most of the isolates were resistant to trimethoprim-sulfamethoxazole (52 %), cefotaxime (51 %), cefepime (43 %), and ceftriaxone (43 %). Among all the 100 isolates, 67 were multidrug-resistant (MDR), and 11 were extensively drug-resistant (XDR). The prevalence of the blaVIM, blaIMP, blaNDM, and blaOXA-48 genes were 7 , 11 , 5 , and 28 %, respectively. The results of biofilm formation in the tissue culture plate assay indicated that 75 (75 %) strains could produce biofilm and only 25 (25 %) isolates were not able to form biofilm. Among these isolates, 25 % formed fully established biofilms, 19 % were categorized as moderately biofilm-producing, 31 % formed weak biofilms, and 25 % were non-biofilm-producers. The antimicrobial resistance among biofilm former strains was found to be significantly higher than that of non-biofilm former strains (p < 0.05). Molecular distribution of biofilm formation genes revealed that 98 , 96 , and 34 % of the isolates carried luxS, treC, and wza genes, respectively.

CONCLUSIONS: The rise of antibiotic resistance among biofilm-producer strains demonstrates a serious concern about limited treatment options in the hospital settings. All of the data suggest that fundamental actions and introduction of novel strategies for controlling of K. pneumoniae biofilm-related infections is essential.}, } @article {pmid33588743, year = {2021}, author = {Tarabal, VS and Silva, FG and Sinisterra, RD and Gonçalves, D and Silva, J and Granjeiro, JM and Speziali, M and Granjeiro, PA}, title = {Impact of DMPEI on Biofilm Adhesion on Latex Urinary Catheter.}, journal = {Recent patents on biotechnology}, volume = {15}, number = {1}, pages = {51-66}, doi = {10.2174/1872208315666210215084127}, pmid = {33588743}, issn = {2212-4012}, mesh = {Biofilms ; Escherichia coli ; Humans ; *Latex ; Patents as Topic ; Staphylococcus aureus ; *Urinary Catheters ; }, abstract = {BACKGROUND: Microorganisms can migrate from the external environment to the patient's organism through the insertion of catheters. Despite being indispensable medical device, the catheter surface can be colonized by microorganisms and become a starting point for biofilm formation. Therefore, new technologies are being developed in order to modify surfaces to prevent the adhesion and survival of microorganisms. Patents with the use of DMPEI have been filed.

OBJECTIVE: In the present work, we coated latex catheter surfaces with 2 mg mL-1 DMPEI in different solvents, evaluated the wettability of the surface and the anti- biofilm activity of the coated catheter against Escherichia coli, Staphylococcus aureus, and Candida albicans.

METHODS: We coated the inner and outer catheter surfaces with 2 mg mL-1 of DMPEI solubilized in butanol, dimethylformamide, and cyclohexanone and the surfaces were analyzed visually. Contact angle measurement allowed the analysis of the wettability of the surfaces. The CFU mL-1 count evaluated E. coli, S. aureus, and C. albicans adhesion onto the control and treated surfaces.

RESULTS: The contact angle decreased from 50.48º to 46.93º on the inner surface and from 55.83º to 50.91º on the outer surface of latex catheters coated with DMPEI. The catheter coated with DMPEI showed anti-biofilm activity of 83%, 88%, and 93% on the inner surface and 100%, 92%, and 86% on the outer surface for E. coli, S. aureus, and C. albicans, respectively.

CONCLUSION: Latex catheter coated with DMPEI efficiently impaired the biofilm formation both on the outer and inner surfaces, showing a potential antimicrobial activity along with a high anti-biofilm activity for medical devices.}, } @article {pmid33588651, year = {2021}, author = {Araujo, TT and Camiloti, GD and Valle, AD and Silva, NDG and Souza, BM and Carvalho, TS and Câmara, JVF and Shibao, PYT and Henrique-Silva, F and Cruvinel, T and Magalhães, AC and Buzalaf, MAR}, title = {A sugarcane cystatin (CaneCPI-5) alters microcosm biofilm formation and reduces dental caries.}, journal = {Biofouling}, volume = {37}, number = {1}, pages = {109-116}, doi = {10.1080/08927014.2021.1881065}, pmid = {33588651}, issn = {1029-2454}, mesh = {Animals ; Biofilms ; Cattle ; *Cystatins ; *Dental Caries/prevention & control ; Humans ; *Saccharum ; Saliva ; Streptococcus mutans ; *Tooth Demineralization ; }, abstract = {The antimicrobial and anticaries effects of CaneCPI-5 were evaluated. Ninety bovine enamel samples were treated for 60 s with either phosphate-buffered-saline (PBS), 0.12% chlorhexidine (CHX), 0.05 mg ml[-1] CaneCPI-5, 0.1 mg ml[-1] CaneCPI-5 or 0.5 mg ml[-1] CaneCPI-5. They were incubated with inoculum (human saliva + McBain's saliva) for the first 8 h. From then until the end of the experiment, the enamel was exposed to McBain saliva with sucrose and, once a day, for 5 days, they were treated with the solutions. At the end of the experimental period, resazurin and viable plate count assays were performed. Enamel demineralization was also measured. All concentrations of CaneCPI-5 and CHX significantly reduced the activity of biofilms compared with PBS. For viable plate counts, all treatments similarly reduced the lactobacilli and total streptococci; for the mutans streptococci, 0.05 mg ml[-1] CaneCPI-5 performed better than CHX. All CaneCPI-5 concentrations significantly reduced the integrated mineral loss. This study represents the first step regarding the use of CaneCPI-5 within the concept of acquired enamel pellicle and biofilm engineering to prevent dental caries.}, } @article {pmid33588649, year = {2021}, author = {Mathlouthi, A and Saadaoui, N and Pennacchietti, E and De Biase, D and Ben-Attia, M}, title = {Essential oils from Artemisia species inhibit biofilm formation and the virulence of Escherichia coli EPEC 2348/69.}, journal = {Biofouling}, volume = {37}, number = {2}, pages = {174-183}, doi = {10.1080/08927014.2021.1886278}, pmid = {33588649}, issn = {1029-2454}, mesh = {*Artemisia ; Biofilms ; *Enteropathogenic Escherichia coli ; *Oils, Volatile/pharmacology ; Virulence ; }, abstract = {Enteropathogenic Escherichia coli E2346/69 (EPEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. The anti-biofilm formation of various components of essential oils extracted from selected medicinal plants were investigated and tested on EPEC and wild strains of E. coli. Oils extracted from the family Asteraceae and their major common constituents at 0.031 and 0.062% (V/v) were found to significantly inhibit biofilm formation without affecting the growth of planktonic cells. In addition, three plants belonging to this family (Artemisia herba alba, Artemisia campestris and Artemisia absinthium) played important roles in the antimicrobial activity. Interestingly, their essential oils reduced the ability of E. coli (the EPEC and K12 strains) to form a biofilm. The crystal violet reduction assay showed that the plant extracts tested reduced biofilm formation with the inhibition of bacterial attachment up to 45% for EPEC and 70% for E. coli K-12 after 24 h treatment at 0.62 mg ml[-1], demonstrating that Artemisia oils had a high anti-biofilm activity on the bacteria tested. The results indicate that the locus of enterocyte effacement (LEE) acquired by horizontal transfer promotes the formation of the attaching and effacing (A/E) lesion and increases the capacity of the photogen strain (EPEC) to form a biofilm. The chemical composition of the volatile compounds was obtained by gas chromatography-mass spectrometry analysis, which showed that the essential oils consisted of thirty-four compounds. Chamazulene (39.21%), β-pinene (32.07%), and α-thujone (29.39%) were the main constituents of the essential oils of A. herba alba, A. absinthium and A. campestris, respectively.}, } @article {pmid33587226, year = {2021}, author = {Semai, A and Plewniak, F and Charrié-Duhaut, A and Sayeh, A and Gil, L and Vandecasteele, C and Lopez-Roques, C and Leize-Wagner, E and Bensalah, F and Bertin, PN}, title = {Characterisation of hydrocarbon degradation, biosurfactant production, and biofilm formation in Serratia sp. Tan611: a new strain isolated from industrially contaminated environment in Algeria.}, journal = {Antonie van Leeuwenhoek}, volume = {114}, number = {4}, pages = {411-424}, pmid = {33587226}, issn = {1572-9699}, support = {ANR-10-INBS-09//France Génomique/ ; scholarship//Algerian Ministry for Higher Education and Scientific Research/ ; }, mesh = {Algeria ; Biodegradation, Environmental ; Biofilms ; Hydrocarbons ; *Petroleum ; RNA, Ribosomal, 16S/genetics ; *Serratia/genetics ; }, abstract = {A novel bacterial strain was isolated from industrially contaminated waste water. In the presence of crude oil, this strain was shown to reduce the rate of total petroleum hydrocarbons (TPH) up to 97.10% in 24 h. This bacterium was subsequently identified by 16S rRNA gene sequence analysis and affiliated to the Serratia genus by the RDP classifier. Its genome was sequenced and annotated, and genes coding for catechol 1,2 dioxygenase and naphthalene 1,2-dioxygenase system involved in aromatic hydrocarbon catabolism, and LadA-type monooxygenases involved in alkane degradation, were identified. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of crude oil after biological treatment showed that Serratia sp. Tan611 strain was able to degrade n-alkanes (from C13 to C25). This bacterium was also shown to produce a biosurfactant, the emulsification index (E24) reaching 43.47% and 65.22%, against vegetable and crude oil, respectively. Finally, the formation of a biofilm was increased in the presence of crude oil. These observations make Serratia sp. Tan611 a good candidate for hydrocarbon bioremediation.}, } @article {pmid33584635, year = {2021}, author = {Joshi, RV and Gunawan, C and Mann, R}, title = {We Are One: Multispecies Metabolism of a Biofilm Consortium and Their Treatment Strategies.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {635432}, pmid = {33584635}, issn = {1664-302X}, abstract = {The ecological and medical significance of bacterial biofilms have been well recognized. Biofilms are harder to control than their planktonic free-living counterparts and quite recently, the focus of the study has shifted to the multispecies consortia, which represent the vast majority of real-case infection scenarios. Studies have begun to explore the complex interspecies interactions within these biofilms. However, only little attention is currently given to the role of cellular metabolites in the cell-to-cell communication. The concentration gradients of metabolic substrates and products affect the spatial growth of bacteria in multispecies biofilm. This, if looked into more deeply, can lead to identification of potential therapies targeting the specific metabolites and hence the coordinated protection in the bacterial community. Herein, we review the interspecies communications, including their metabolic cross-talking, in multispecies biofilm, to signify the importance of such interactions on the initial formation and subsequent growth of these biofilms. Multispecies biofilms with their species heterogeneity are more resilient to antimicrobial agents than their single species biofilm counterparts and this characteristic is of particular interest when dealing with pathogenic bacteria. In this Review, we also discuss the treatment options available, to include current and emerging avenues to combat pathogenic multispecies biofilms in the clinical, environmental, as well as industrial settings.}, } @article {pmid33584628, year = {2021}, author = {Scheper, H and Wubbolts, JM and Verhagen, JAM and de Visser, AW and van der Wal, RJP and Visser, LG and de Boer, MGJ and Nibbering, PH}, title = {SAAP-148 Eradicates MRSA Persisters Within Mature Biofilm Models Simulating Prosthetic Joint Infection.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {625952}, pmid = {33584628}, issn = {1664-302X}, abstract = {Prosthetic joint infection (PJI) is a severe complication of arthroplasty. Due to biofilm and persister formation current treatment strategies often fail. Therefore, innovative anti-biofilm and anti-persister agents are urgently needed. Antimicrobial peptides with their broad antibacterial activities may be such candidates. An in vitro model simulating PJI comprising of rifampicin/ciprofloxacin-exposed, mature methicillin-resistant Staphylococcus aureus (MRSA) biofilms on polystyrene plates, titanium/aluminium/niobium disks, and prosthetic joint liners were developed. Bacteria obtained from and residing within these biofilms were exposed to SAAP-148, acyldepsipeptide-4, LL-37, and pexiganan. Microcalorimetry was used to monitor the heat flow by the bacteria in these models. Daily exposure of mature biofilms to rifampicin/ciprofloxacin for 3 days resulted in a 4-log reduction of MRSA. Prolonged antibiotic exposure did not further reduce bacterial counts. Microcalorimetry confirmed the low metabolic activity of these persisters. SAAP-148 and pexiganan, but not LL-37, eliminated the persisters while ADEP4 reduced the number of persisters. SAAP-148 further eradicated persisters within antibiotics-exposed, mature biofilms on the various surfaces. To conclude, antibiotic-exposed, mature MRSA biofilms on various surfaces have been developed as in vitro models for PJI. SAAP-148 is highly effective against persisters obtained from the biofilms as well as within these models. Antibiotics-exposed, mature biofilms on relevant surfaces can be instrumental in the search for novel treatment strategies to combat biofilm-associated infections.}, } @article {pmid33584610, year = {2021}, author = {Melian, C and Castellano, P and Segli, F and Mendoza, LM and Vignolo, GM}, title = {Proteomic Analysis of Listeria monocytogenes FBUNT During Biofilm Formation at 10°C in Response to Lactocin AL705.}, journal = {Frontiers in microbiology}, volume = {12}, number = {}, pages = {604126}, pmid = {33584610}, issn = {1664-302X}, abstract = {Listeria monocytogenes is one of the major food-related pathogens and is able to survive and multiply under different stress conditions. Its persistence in industrial premises and foods is partially due to its ability to form biofilm. Thus, as a natural strategy to overcome L. monocytogenes biofilm formation, the treatment with lactocin AL705 using a sublethal dose (20AU/ml) was explored. The effect of the presence of the bacteriocin on the biofilm formation at 10°C of L. monocytogenes FBUNT was evaluated for its proteome and compared to the proteomes of planktonic and sessile cells grown at 10°C in the absence of lactocin. Compared to planktonic cells, adaptation of sessile cells during cold stress involved protein abundance shifts associated with ribosomes function and biogenesis, cell membrane functionality, carbohydrate and amino acid metabolism, and transport. When sessile cells were treated with lactocin AL705, proteins' up-regulation were mostly related to carbohydrate metabolism and nutrient transport in an attempt to compensate for impaired energy generation caused by bacteriocin interacting with the cytoplasmic membrane. Notably, transport systems such as β-glucosidase IIABC (lmo0027), cellobiose (lmo2763), and trehalose (lmo1255) specific PTS proteins were highly overexpressed. In addition, mannose (lmo0098), a specific PTS protein indicating the adaptive response of sessile cells to the bacteriocin, was downregulated as this PTS system acts as a class IIa bacteriocin receptor. A sublethal dose of lactocin AL705 was able to reduce the biofilm formation in L. monocytogenes FBUNT and this bacteriocin induced adaptation mechanisms in treated sessile cells. These results constitute valuable data related to specific proteins targeting the control of L. monocytogenes biofilm upon bacteriocin treatment.}, } @article {pmid33584576, year = {2020}, author = {Bharti, S and Maurya, RK and Venugopal, U and Singh, R and Akhtar, MS and Krishnan, MY}, title = {Rv1717 Is a Cell Wall - Associated β-Galactosidase of Mycobacterium tuberculosis That Is Involved in Biofilm Dispersion.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {611122}, pmid = {33584576}, issn = {1664-302X}, abstract = {Understanding the function of conserved hypothetical protein (CHP)s expressed by a pathogen in the infected host can lead to better understanding of its pathogenesis. The present work describes the functional characterization of a CHP, Rv1717 of Mycobacterium tuberculosis (Mtb). Rv1717 has been previously reported to be upregulated in TB patient lungs. Rv1717 belongs to the cupin superfamily of functionally diverse proteins, several of them being carbohydrate handling proteins. Bioinformatic analysis of the amino acid sequence revealed similarity to glycosyl hydrolases. Enzymatic studies with recombinant Rv1717 purified from Escherichia coli showed that the protein is a β-D-galactosidase specific for pyranose form rather than the furanose form. We expressed the protein in Mycobacterium smegmatis (Msm), which lacks its ortholog. In Msm [Rv1717] , the protein was found to localize to the cell wall (CW) with a preference to the poles. Msm [Rv1717] showed significant changes in colony morphology and cell surface properties. Most striking observation was its unusual Congo red colony morphotype, reduced ability to form biofilms, pellicles and autoagglutinate. Exogenous Rv1717 not only prevented biofilm formation in Msm, but also degraded preformed biofilms, suggesting that its substrate likely exists in the exopolysaccharides of the biofilm matrix. Presence of galactose in the extracellular polymeric substance (EPS) has not been reported before and hence we used the galactose-specific Wisteria floribunda lectin (WFL) to test the same. The lectin extensively bound to Msm and Mtb EPS, but not the bacterium per se. Purified Rv1717 also hydrolyzed exopolysaccharides extracted from Msm biofilm. Eventually, to decipher its role in Mtb, we downregulated its expression and demonstrate that the strain is unable to disperse from in vitro biofilms, unlike the wild type. Biofilms exposed to carbon starvation showed a sudden upregulation of Rv1717 transcripts supporting the potential role of Rv1717 in Mtb dispersing from a deteriorating biofilm.}, } @article {pmid33584103, year = {2021}, author = {Kim, D and Kim, W and Kim, J}, title = {New Bacterial Surface Display System Development and Application Based on Bacillus subtilis YuaB Biofilm Component as an Anchoring Motif.}, journal = {Biotechnology and bioprocess engineering : BBE}, volume = {26}, number = {1}, pages = {39-46}, pmid = {33584103}, issn = {1226-8372}, abstract = {Bacterial surface display system has been adopted in various biotechnological applications. In the case of Bacillus subtilis, most of the studies have been developed using spore based surface display system utilizing the inherent rigidity of spore against heat, alkali, and shear stress. But, spore harvest, purification and separation need additional cost and labor. To eliminate this procedure and to use the gram-positive nature of B. subtilis, YuaB, which is one of the major B. subtilis biofilm components and locates in the cell wall, based cell surface display system, is developed. P43 promoter driven overexpression of YuaB-His6 tag does not hamper bacterial cell growth and promoted biofilm formation of recombinant strain. Flow cytometry of recombinant strain and its protoplast using FITC-Anti His6 antibody, verified that YuaB locate in plasma membrane and protrude to the outside of cell wall, which means YuaB can be used as very efficient anchoring motif. Using surface expressed YuaB-His6 tag, removal of divalent metal ion, Cu[2+] and Ni[2+], was tried to test its possibility for the environmental application of developed system.}, } @article {pmid33583879, year = {2021}, author = {Okamoto-Shibayama, K and Yoshida, A and Ishihara, K}, title = {Inhibitory Effect of Resveratrol on Candida albicans Biofilm Formation.}, journal = {The Bulletin of Tokyo Dental College}, volume = {62}, number = {1}, pages = {1-6}, doi = {10.2209/tdcpublication.2020-0023}, pmid = {33583879}, issn = {0040-8891}, mesh = {Biofilms ; *Candida albicans ; *Candidiasis ; Humans ; Hyphae ; Resveratrol/pharmacology ; }, abstract = {Candida albicans is the primary candidiasis-causing fungal pathogen in humans, and one of its most important virulence factors is the ability to form biofilms. Moreover, these biofilms are often resistant to antifungal agents, so there is a need to develop alternative elimination strategies and therapeutic agents for such infections. The antifungal activity of resveratrol, a phytoalexin polyphenolic compound, impairs the morphological transition of C. albicans under various hypha-inducing conditions and inhibits growth of the yeast-form and mycelia. The purpose of this study was to investigate the effect of resveratrol against C. albicans biofilm formation. The developmental, sustained, and mature stages of biofilm formation were affected or inhibited by resveratrol. Exposure to resveratrol at the developmental stage inhibited growth of C. albicans in a dose-dependent manner. A >30% reduction was observed in sustained biofilm growth in the presence of 200 μg/ml resveratrol in comparison with in its absence. In terms of disruption of matured biofilm, 6.25-100 μg/ml resveratrol significantly reduced cell viability of C. albicans compared with in a control sample (p<0.05). The present results indicate that resveratrol has the potential to serve as an anti-Candida treatment and preventive tool which functions by inhibiting existing or under-forming C. albicans biofilms.}, } @article {pmid33583105, year = {2022}, author = {Xiong, K and Chen, X and Zhu, H and Ji, M and Zou, L}, title = {Anticaries activity of GERM CLEAN in Streptococcus mutans and Candida albicans dual-species biofilm.}, journal = {Oral diseases}, volume = {28}, number = {3}, pages = {829-839}, doi = {10.1111/odi.13799}, pmid = {33583105}, issn = {1601-0825}, support = {2020YFSY0019//Project of the Science and Technology Department of Sichuan Province/ ; }, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Biofilms ; Candida albicans ; Cattle ; *Dental Caries/prevention & control ; Dental Enamel ; Streptococcus mutans ; }, abstract = {OBJECTIVE: To evaluate the antimicrobial effects of a peptide containing novel oral spray GERM CLEAN on dual-species biofilm formed by Streptococcus mutans and Candida albicans and to investigate whether GERM CLEAN inhibits the demineralization procedure of bovine enamel in vitro.

METHODS: The antimicrobial effects of GERM CLEAN on dual-species biofilm were analyzed by initial adherence rate calculation, water-insoluble exopolysaccharides quantification, total biomass quantification, and colony-forming units (CFUs) counting. Scanning electron microscopy and confocal laser scanning microscopy were applied to evaluate the impacts of GERM CLEAN on the biofilm structure. Further, the effects of GERM CLEAN on acidogenicity of dual-species were appraised via glycolytic pH drop analysis and hydroxyapatite dissolution measurement. The percentage of Surface Microhardness Reduction (%SMHR) evaluation, Atomic Force Micrograph (AFM) examination, and Transverse Microradiography (TMR) analysis after pH cycling were used to determine whether GERM CLEAN inhibited the demineralization of bovine enamel.

RESULTS: GERM CLEAN decreased the adherence rate, water-insoluble EPS production, biofilm formation, and acidogenicity of the dual-species. Moreover, GERM CLEAN significantly inhibited the demineralization status of bovine enamels.

CONCLUSION: This peptide containing novel oral spray GERM CLEAN has antimicrobial potential toward the dual-species. GERM CLEAN can also impede the demineralization procedure of enamel.}, } @article {pmid33581548, year = {2021}, author = {Greve, D and Moter, A and Kleinschmidt, MC and Pfäfflin, F and Stegemann, MS and Kursawe, L and Grubitzsch, H and Falk, V and Kikhney, J}, title = {Rothia aeria and Rothia dentocariosa as biofilm builders in infective endocarditis.}, journal = {International journal of medical microbiology : IJMM}, volume = {311}, number = {2}, pages = {151478}, doi = {10.1016/j.ijmm.2021.151478}, pmid = {33581548}, issn = {1618-0607}, mesh = {*Biofilms ; Endocarditis, Bacterial/*microbiology ; Humans ; In Situ Hybridization, Fluorescence ; Micrococcaceae/*pathogenicity ; }, abstract = {BACKGROUND: Rothia sp. are Gram-positive bacteria in the class of Actinobacteria that are part of the physiological oral flora. In rare cases, Rothia aeria and Rothia dentocariosa can cause infective endocarditis (IE). The biofilm potential of Rothia in endocarditis is unknown.

METHODS: Specimen from two cases of Rothia endocarditis were obtained during cardiac surgery. One of the patients suffered mitral valve IE from Rothia aeria. In the other case, IE of a prosthetic pulmonary valve was caused by Rothia dentocariosa. Fluorescence in situ hybridization (FISH) was used for visualization of microorganisms within heart valve tissues in combination with PCR and sequencing (FISHseq).

RESULTS: The two heart valve specimens featured mature biofilms of bacteria that were identified by FISHseq as Rothia aeria and Rothia dentocariosa, respectively. FISH showed in situ biofilms of both microorganisms that feature distinct phenotypes for the first time ex vivo. Both of our reported cases were treated successfully by heart valve surgery and antibiotic therapy using beta-lactam antibiotics.

CONCLUSION: The biofilm potential of Rothia sp. must be taken into account. The awareness of Rothia aeria and Rothia dentocariosa as rare but relevant pathogens for infective endocarditis must be raised. Use of biofilm-effective antibiotics in Rothia IE should be discussed.}, } @article {pmid33581528, year = {2021}, author = {Wang, F and Xu, S and Liu, L and Wang, S and Ji, M}, title = {One-stage partial nitrification and anammox process in a sequencing batch biofilm reactor: Start-up, nitrogen removal performance and bacterial community dynamics in response to temperature.}, journal = {The Science of the total environment}, volume = {772}, number = {}, pages = {145529}, doi = {10.1016/j.scitotenv.2021.145529}, pmid = {33581528}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; Bioreactors ; Denitrification ; *Nitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Temperature ; }, abstract = {A one-stage partial nitrification and anammox (PN/A) process was started up and operated under varying temperatures in a lab-scale sequencing batch biofilm reactor. The start‑up phase took 110 days with an intermittent aeration strategy, and the removal efficiencies of ammonia‑nitrogen and total nitrogen were found to be 92.22% and 76.07%, respectively. The total nitrogen removal efficiency (NRE) increased by 9.49% when temperature decreased from 30 °C to 25 °C, but declined by 83.84% from 25 °C to 20 °C. The PN process was inhibited and subsequently limited the nitrogen removal performance at 20 °C. When temperature returned to 28 °C, the NRE recovered to 67.27%, but it was still lower than the value before the decrease in temperature (79.40%). Microbial community analysis showed that the predominant ammonia oxidation bacteria and anammox bacteria were Nitrosomonas and Candidatus Kuenenia, respectively. Nitrosomonas grew, while the relative abundance of Candidatus Kuenenia increased as temperature decreased and vice versa.}, } @article {pmid33581401, year = {2021}, author = {Torkzadeh, H and Zodrow, KR and Bridges, WC and Cates, EL}, title = {Quantification and modeling of the response of surface biofilm growth to continuous low intensity UVC irradiation.}, journal = {Water research}, volume = {193}, number = {}, pages = {116895}, doi = {10.1016/j.watres.2021.116895}, pmid = {33581401}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; Disinfection ; *Escherichia coli ; *Ultraviolet Rays ; }, abstract = {Though germicidal UV radiation is widely applied for disinfection of water and food, it may also be used to prevent bacterial growth and colonization on surfaces within engineered systems. Emerging UV source technologies, such as ultraviolet-C (UVC) LEDs, present new opportunities for deterring biofilms within certain devices, including medical equipment, food equipment, and potentially in plumbing fixtures for prevention of opportunistic respiratory pathogen infections. Rational design for incorporation of UVC sources into devices with complex internal geometries is currently hampered by the lack of an engineering framework for predicting reductions in biofilm growth rates in response to continuous low-intensity irradiation. Herein we have developed an experimental apparatus and method for growing biofilms under concurrent UV irradiation and quantifying the resulting suppression of surface growth. Under accelerated growth conditions over 48 h, E. coli surface biovolume was reduced by 95% compared to control biofilms (grown in the dark) by a UV intensity of 50.5 µW/cm[2] (254 nm). The required intensity for biofilm prevention was higher than expected, given the UV dose response of the bacteria employed and the cumulative doses delivered to the test surfaces. The results indicate that biofilms can establish even under irradiation conditions that would result in complete inactivation of planktonic cells, likely due to the shielding effects of colloidal material and microbial exudates. A pseudo-mechanistic model was also developed which correlated UV intensity to the resultant reduction in specific surface biovolume.}, } @article {pmid33581085, year = {2021}, author = {Zan, F and Guo, G and Zheng, T and Chen, G}, title = {Biofilm development in a pilot-scale gravity sewer: Physical characteristics, microstructure, and microbial communities.}, journal = {Environmental research}, volume = {195}, number = {}, pages = {110838}, doi = {10.1016/j.envres.2021.110838}, pmid = {33581085}, issn = {1096-0953}, mesh = {Bacteria ; Biofilms ; *Microbiota ; *Sewage ; Sulfides ; }, abstract = {The existence of abundant biofilms on sewer pipeline walls can lead to negative environmental impacts, such as poisonous gas release and pipe corrosions through transforming various pollutants. Investigating the formation process of sewer biofilms is of importance in advancing knowledge of sewer operation and maintenance. In this study, the changes in physical characteristics, microstructure, and microbial communities of sewer biofilm were analyzed in-depth in a pilot-scale gravity sewer during a 45-day operation. The results show that a high specific surface area at the early stage could channel the substrates for stimulating the primary colonizers (e.g., Cytophagia, Sphingobacteriia, Alpha-, and Betaproteobacteria), which could excrete an extracellular matrix to facilitate biofilm growth. The sewer biofilms were gradually formed with 62 g VS/m[2] organic content, 1.2 mm biofilm thickness, and 89 mg/cm[3] dry density after 45 days operation. Moreover, the biofilm growth promoted the emergence of facultative bacteria and anaerobes (affiliated with Flavobacteriia, Gemmatimonadetes, Deltaproteobacteria, and Epsilonproteobacteria). Microelectrode analysis further verified that an anaerobic zone existed in mature biofilm with a negative oxidation-reduction potential (-105 mV), where approximately 0.1 μmol/L of sulfide was produced. Our results suggest that the migration of the microbial community correlated with the changes in the evolved physical characteristics and microstructure of sewer biofilm, and this can contribute to the strategies for sulfide control for improving sewer maintenance.}, } @article {pmid33580656, year = {2021}, author = {Walker, JN and Myckatyn, T}, title = {Commentary on: Biofilm Formation on Breast Implant Surfaces by Major Gram-Positive Bacterial Pathogens.}, journal = {Aesthetic surgery journal}, volume = {41}, number = {10}, pages = {1152-1154}, doi = {10.1093/asj/sjaa400}, pmid = {33580656}, issn = {1527-330X}, mesh = {Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; Humans ; Staphylococcus epidermidis ; }, } @article {pmid33580263, year = {2021}, author = {Fourie, R and Cason, ED and Albertyn, J and Pohl, CH}, title = {Transcriptional response of Candida albicans to Pseudomonas aeruginosa in a polymicrobial biofilm.}, journal = {G3 (Bethesda, Md.)}, volume = {11}, number = {4}, pages = {}, pmid = {33580263}, issn = {2160-1836}, mesh = {Biofilms ; *Candida albicans/genetics ; Hyphae ; *Pseudomonas aeruginosa/genetics ; }, abstract = {Candida albicans is frequently co-isolated with the Gram-negative bacterium, Pseudomonas aeruginosa. In vitro, the interaction is complex, with both species influencing each other. Not only does the bacterium kill hyphal cells of C. albicans through physical interaction, it also affects C. albicans biofilm formation and morphogenesis, through various secreted factors and cell wall components. The present study sought to expand the current knowledge regarding the interaction between C. albicans and P. aeruginosa, using transcriptome analyses of early static biofilms. Under these conditions, a total of 2,537 open reading frames (approximately 40% of the C. albicans transcriptome) was differentially regulated in the presence of P. aeruginosa. Upon deeper analyses it became evident that the response of C. albicans toward P. aeruginosa was dominated by a response to hypoxia, and included those associated with stress as well as iron and zinc homeostasis. These conditions may also lead to the observed differential regulation of genes associated with cell membrane synthesis, morphology, biofilm formation and phenotypic switching. Thus, C. albicans in polymicrobial biofilms with P. aeruginosa have unique transcriptional profiles that may influence commensalism as well as pathogenesis.}, } @article {pmid33579493, year = {2021}, author = {Valliammai, A and Selvaraj, A and Mathumitha, P and Aravindraja, C and Pandian, SK}, title = {Polymeric antibiofilm coating comprising synergistic combination of citral and thymol prevents methicillin-resistant Staphylococcus aureus biofilm formation on titanium.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {121}, number = {}, pages = {111863}, doi = {10.1016/j.msec.2021.111863}, pmid = {33579493}, issn = {1873-0191}, mesh = {Acyclic Monoterpenes ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; Leukocytes, Mononuclear ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Prospective Studies ; Thymol ; Titanium/pharmacology ; }, abstract = {Biomaterial associated microbial infections are complicated and mostly lead to revision surgery or removal which are painful to the patients and quite expensive. These infections are difficult to treat with antibiotics as it is often related to biofilm formation. Methicillin resistant Staphylococcus aureus (MRSA) is the leading pathogen in biomaterial associated infections and well known to form biofilm on foreign materials. To reduce the risk of biomaterial associated infections, recent treatment strategies focus on modification of the implant surface to prevent the adhesion of bacteria. Antibiofilm coating is the effective approach than coating with antimicrobials as antibiofilm agents will not create selective pressure thereby excludes possibility of drug resistance. The current study identified and validated the synergistic antibiofilm activity of citral (CIT) and thymol (THY) by crystal violet quantification and microscopic analysis without alteration in growth and metabolic viability of MRSA. Polymeric antibiofilm coating with CIT + THY as active ingredients was formulated and coated on titanium surface by the process of spin coating. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the effective blending of polymeric formulation and the presence of CIT and THY. Atomic force microscopy (AFM) images revealed the homogenous coating and reduced surface roughness and thickness of the coating was measured by surface profilometer. Antibiofilm coating released CIT and THY in a sustained manner for 60 days. Antibiofilm coating effectively inhibited MRSA adherence in vitro and antibiofilm activity of coating was not affected by plasma conditioning. In addition, antibiofilm coating was non-hemolytic and non-toxic to PBMC. Thus, the current study demonstrated the effectual strategy to prevent biomaterial associated infections and proposes the prospective role of antibiofilm coating in clinical applications.}, } @article {pmid33578658, year = {2021}, author = {Topka-Bielecka, G and Dydecka, A and Necel, A and Bloch, S and Nejman-Faleńczyk, B and Węgrzyn, G and Węgrzyn, A}, title = {Bacteriophage-Derived Depolymerases against Bacterial Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33578658}, issn = {2079-6382}, support = {2015/17/B/NZ9/01724//Narodowe Centrum Nauki/ ; }, abstract = {In addition to specific antibiotic resistance, the formation of bacterial biofilm causes another level of complications in attempts to eradicate pathogenic or harmful bacteria, including difficult penetration of drugs through biofilm structures to bacterial cells, impairment of immunological response of the host, and accumulation of various bioactive compounds (enzymes and others) affecting host physiology and changing local pH values, which further influence various biological functions. In this review article, we provide an overview on the formation of bacterial biofilm and its properties, and then we focus on the possible use of phage-derived depolymerases to combat bacterial cells included in this complex structure. On the basis of the literature review, we conclude that, although these bacteriophage-encoded enzymes may be effective in destroying specific compounds involved in the formation of biofilm, they are rarely sufficient to eradicate all bacterial cells. Nevertheless, a combined therapy, employing depolymerases together with antibiotics and/or other antibacterial agents or factors, may provide an effective approach to treat infections caused by bacteria able to form biofilms.}, } @article {pmid33577624, year = {2021}, author = {Jung, CJ and Hsu, CC and Chen, JW and Cheng, HW and Yuan, CT and Kuo, YM and Hsu, RB and Chia, JS}, title = {PspC domain-containing protein (PCP) determines Streptococcus mutans biofilm formation through bacterial extracellular DNA release and platelet adhesion in experimental endocarditis.}, journal = {PLoS pathogens}, volume = {17}, number = {2}, pages = {e1009289}, pmid = {33577624}, issn = {1553-7374}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/*metabolism ; Endocarditis/metabolism/*microbiology/pathology ; Extracellular Space/metabolism ; Healthy Volunteers ; Host-Pathogen Interactions ; Humans ; *Platelet Adhesiveness ; Rats ; Streptococcal Infections/metabolism/*microbiology/pathology ; Streptococcus mutans/genetics/*growth & development ; }, abstract = {Bacterial extracellular DNA (eDNA) and activated platelets have been found to contribute to biofilm formation by Streptococcus mutans on injured heart valves to induce infective endocarditis (IE), yet the bacterial component directly responsible for biofilm formation or platelet adhesion remains unclear. Using in vivo survival assays coupled with microarray analysis, the present study identified a LiaR-regulated PspC domain-containing protein (PCP) in S. mutans that mediates bacterial biofilm formation in vivo. Reverse transcriptase- and chromatin immunoprecipitation-polymerase chain reaction assays confirmed the regulation of pcp by LiaR, while PCP is well-preserved among streptococcal pathogens. Deficiency of pcp reduced in vitro and in vivo biofilm formation and released the eDNA inside bacteria floe along with reduced bacterial platelet adhesion capacity in a fibrinogen-dependent manner. Therefore, LiaR-regulated PCP alone could determine release of bacterial eDNA and binding to platelets, thus contributing to biofilm formation in S. mutans-induced IE.}, } @article {pmid33576985, year = {2021}, author = {Allkja, J and Azevedo, AS}, title = {Characterization of Social Interactions and Spatial Arrangement of Individual Bacteria in MultiStrain or Multispecies Biofilm Systems Using Nucleic Acid Mimics-Fluorescence In Situ Hybridization.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2246}, number = {}, pages = {97-109}, pmid = {33576985}, issn = {1940-6029}, mesh = {Bacteria/*genetics ; Biofilms/*growth & development ; Fluorescence ; In Situ Hybridization, Fluorescence/*methods ; Microscopy, Confocal/*methods ; Nucleic Acids/*genetics ; }, abstract = {Biofilms are often composed of different bacterial and fungal species/strains, which form complex structures based on social interactions with each other. Fluorescence in situ hybridization (FISH) can help us identify the different species/strains present within a biofilm , and when coupled with confocal scanning laser microscopy (CSLM), it enables the visualization of the three-dimensional (3D) structure of the biofilm and the spatial arrangement of each individual species/strain within it. In this chapter, we describe the protocol for characterizing multistrain or multispecies biofilm formation using NAM-FISH and CSLM.}, } @article {pmid33575326, year = {2021}, author = {Elgueta, E and Mena, J and Orihuela, PA}, title = {Hydroethanolic Extracts of Haplopappus baylahuen Remy and Aloysia citriodora Palau Have Bactericide Activity and Inhibit the Ability of Salmonella Enteritidis to Form Biofilm and Adhere to Human Intestinal Cells.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {3491831}, pmid = {33575326}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Antioxidants/administration & dosage ; *Biofilms ; Caco-2 Cells ; Cells, Cultured ; Ethanol/*administration & dosage/isolation & purification ; Haplopappus/chemistry ; Humans ; Intestines/*drug effects ; Phenols/isolation & purification ; Plant Extracts/*administration & dosage ; Salmonella enteritidis/*drug effects/*physiology ; Verbenaceae/chemistry ; }, abstract = {We analysed whether the hydroethanolic extracts from leaves of Haplopappus baylahuen Remy (bailahuen) and Aloysia citriodora Palau (cedron) inhibit the growth and ability of Salmonella Enteritidis to form biofilms and to adhere to human intestinal epithelial cells. Herein, we first determined the total phenolic content and antioxidant and antibacterial activities of the extracts. Then, Salmonella Enteritidis was treated with the extracts to analyse biofilm formation by scanning electronic microscopy and the violet crystal test. We also measured the efflux pump activity of Salmonella Enteritidis since biofilm formation is associated with this phenomenon. Furthermore, the human intestinal cell line Caco-2 was infected with Salmonella Enteritidis pretreated with the extracts, and 30 min later, the number of bacteria that adhered to the cell surface was quantified. Finally, we determined by qPCR the expression of genes associated with biofilm formation, namely, the diguanilate cyclase AdrA protein gene (adrA) and the BapA protein gene (bapA), and genes associated with adhesion, namely, the transcriptional regulator HilA (hilA). The phenolic content and antioxidant and bactericide activities were higher in bailahuen than in the cedron extract. Biofilm formation was inhibited by the extracts in a dose-dependent manner, while the activity of efflux pumps was decreased only with the cedron extract. Adhesion to Caco-2 cells was also inhibited without differences between doses and extracts. The extracts decreased the expression of adrA; with the cedron extract being the most efficient. The expression of hilA is affected only with the cedron extract. We concluded that hydroethanolic extracts of bailahuen and cedron differentially inhibit the growth of Salmonella Enteritidis and affect its the ability to form biofilms and to adhere to human intestinal epithelial cells. These results highlight the presence of molecules in bailahuen and cedron with a high potential for the control of the Salmonella Enteritidis pathogenesis.}, } @article {pmid33575161, year = {2020}, author = {Mori, DI and Schurr, MJ and Nair, DP}, title = {Selective Inhibition of Streptococci Biofilm Growth via a Hydroxylated Azobenzene Coating.}, journal = {Advanced materials interfaces}, volume = {7}, number = {15}, pages = {}, pmid = {33575161}, issn = {2196-7350}, support = {K25 DE027418/DE/NIDCR NIH HHS/United States ; }, abstract = {Strategies to engineer surfaces that can enable the selective inhibition of bacterial pathogens while preserving beneficial microbes can serve as tools to precisely edit the microbiome. In the oral microbiome, this selectivity is crucial in preventing the proliferation of cariogenic species such as Streptococcus mutans (S. mutans). In this communication, coatings consisting of a covalently tethered hydroxylated azobenzene (OH-AAZO) on glassy acrylic resins are studied and characterized for their ability to selectively prevent the attachment and growth of oral Streptococci biofilms. The coating applied on the surface of glassy resins inhibits the growth and proliferation of cariogenic S. mutans and S. oralis biofilms while A. actinomycetemcomitans, S. aureus, and E. coli biofilms are unaffected by the coating . The antibacterial effect is characterized as a function of both the OH-AAZO concentration in the coatings (≥50 mg mL[-1]) and the structure of the monomer in the coating. Preliminary mechanistic results suggest that the targeted bactericidal effect against Streptococci species is caused by a disruption of membrane ion potential, inducing cell death.}, } @article {pmid33574871, year = {2020}, author = {Akinola, SA and Tshimpamba, ME and Mwanza, M and Ateba, CN}, title = {Biofilm Production Potential of Salmonella Serovars Isolated from Chickens in North West Province, South Africa.}, journal = {Polish journal of microbiology}, volume = {69}, number = {4}, pages = {427-439}, pmid = {33574871}, issn = {2544-4646}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Chickens/*microbiology ; Culture Media ; Food Microbiology ; Salmonella/classification/isolation & purification/*physiology ; Salmonella enterica/classification/isolation & purification/*physiology ; Serogroup ; South Africa ; Temperature ; }, abstract = {Bacterial biofilms have recently gained considerable interest in the food production and medical industries due to their ability to resist destruction by disinfectants and other antimicrobials. Biofilms are extracellular polymer matrices that may enhance the survival of pathogens even when exposed to environmental stress. The effect of incubation temperatures (25°C, 37°C, and 40°C) and Salmonella serotype on biofilm-forming potentials was evaluated. Previously typed Salmonella serotypes (55) isolated from the gut of chickens were accessed for biofilms formation using a standard assay. Salmonella Typhimurium ATCC 14028[TM] and Salmonella Enteritidis ATCC 13076[TM] (positive controls), Escherichia coli (internal control) and un-inoculated Luria Bertani (LB) broth (negative control) were used. The isolates formed no biofilm (11.86-13.56%), weak (11.86-45.76%), moderate (18.64-20.34%), strong biofilms (23.73-54.24%) across the various temperatures investigated. Serotypes, Salmonella Heidelberg and Salmonella Weltevreden were the strongest biofilm formers at temperatures (25°C, 37°C, and 40°C, respectively). The potential of a large proportion (80%) of Salmonella serotypes to form biofilms increased with increasing incubation temperatures but decreased at 40°C. Findings indicate that average temperature favours biofilm formation by Salmonella serotypes. However, the influence of incubation temperature on biofilm formation was greater when compared to serotype. A positive correlation exists between Salmonella biofilm formed at 25°C, 37°C and 40°C (p ≥ 0.01). The ability of Salmonella species to form biofilms at 25°C and 37°C suggests that these serotypes may present severe challenges to food-processing and hospital facilities.}, } @article {pmid33574869, year = {2020}, author = {Kİlİc, T}, title = {Biofilm-Forming Ability and Effect of Sanitation Agents on Biofilm-Control of Thermophile Geobacillus sp. D413 and Geobacillus toebii E134.}, journal = {Polish journal of microbiology}, volume = {69}, number = {4}, pages = {411-419}, pmid = {33574869}, issn = {2544-4646}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacillaceae/drug effects/*growth & development ; Biofilms/drug effects/*growth & development ; DNA, Bacterial/chemistry/metabolism ; Deoxyribonuclease I/metabolism ; Endopeptidase K/metabolism ; Geobacillus/drug effects/*growth & development ; Nisin/pharmacology ; Nucleic Acid Conformation ; Ribonuclease, Pancreatic/metabolism ; alpha-Amylases/pharmacology ; }, abstract = {Geobacillus sp. D413 and Geobacillus toebii E134 are aerobic, non-pathogenic, endospore-forming, obligately thermophilic bacilli. Gram-positive thermophilic bacilli can produce heat-resistant spores. The bacteria are indicator organisms for assessing the manufacturing process's hygiene and are capable of forming biofilms on surfaces used in industrial sectors. The present study aimed to determine the biofilm-forming properties of Geobacillus isolates and how to eliminate this formation with sanitation agents. According to the results, extracellular DNA (eDNA) was interestingly not affected by the DNase I, RNase A, and proteinase K. However, the genomic DNA (gDNA) was degraded by only DNase I. It seemed that the eDNA had resistance to DNase I when purified. It is considered that the enzymes could not reach the target eDNA. Moreover, the eDNA resistance may result from the conserved folded structure of eDNA after purification. Another assumption is that the eDNA might be protected by other extracellular polymeric substances (EPS) and/or extracellular membrane vesicles (EVs) structures. On the contrary, DNase I reduced unpurified eDNA (mature biofilms). Biofilm formation on surfaces used in industrial areas was investigated in this work: the D413 and E134 isolates adhered to all surfaces. Various sanitation agents could control biofilms of Geobacillus isolates. The best results were provided by nisin for D413 (80%) and α-amylase for E134 (98%). This paper suggests that sanitation agents could be a solution to control biofilm structures of thermophilic bacilli.}, } @article {pmid33574683, year = {2021}, author = {Wang, Y and Pei, Z and Lou, Z and Wang, H}, title = {Evaluation of Anti-Biofilm Capability of Cordycepin Against Candida albicans.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {435-448}, pmid = {33574683}, issn = {1178-6973}, abstract = {INTRODUCTION: The opportunistic pathogen Candida albicans can form biofilms, resulting in drug resistance with great risk to medical treatment.

METHODOLOGY: We investigated the ability of C. albicans to form biofilms on different materials, as well as the inhibitory and eradicating effects of cordycepin on biofilm. The action mechanism of cordycepin against biofilm was studied by crystal violet staining, XTT [2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction method, phenol-sulfuric acid method, cellular superficial hydrophobicity (CSH) assay, and confocal laser scanning microscope observation. We also evaluated the acute toxicity of cordycepin in vivo.

RESULTS: The results showed facile formation of biofilms by C. albicans on polypropylene. The 50% minimum inhibitory concentration (MIC50) of cordycepin was 0.062 mg/mL. A concentration of 0.125 mg/mL significantly decreased biofilm formation, metabolic activity, secretion of extracellular polysaccharides, and relative CSH. Cordycepin could inhibit biofilm formation at low concentration without affecting fungal growth. In addition, cordycepin effectively eradicated 59.14% of mature biofilms of C. albicans at a concentration of 0.5 mg/mL. For acute toxicity, the LD50 (50% of lethal dose) of cordycepin was determined as higher than 500 mg/kg for mice.

CONCLUSION: The results of this study show that cordycepin significantly inhibited and eradicated biofilms by decreasing metabolic activity, the ratio of living cells, the hydrophobicity, and damaging the extracellular polysaccharides of biofilm. These findings should facilitate more effective application of cordycepin and suggest a new direction for the treatment of fungal infections.}, } @article {pmid33574464, year = {2021}, author = {Ishihama, H and Ishii, K and Nagai, S and Kakinuma, H and Sasaki, A and Yoshioka, K and Kuramoto, T and Shiono, Y and Funao, H and Isogai, N and Tsuji, T and Okada, Y and Koyasu, S and Toyama, Y and Nakamura, M and Aizawa, M and Matsumoto, M}, title = {An antibacterial coated polymer prevents biofilm formation and implant-associated infection.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {3602}, pmid = {33574464}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Benzophenones/chemistry/pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*pharmacology ; Durapatite/chemistry/pharmacology ; Humans ; Metal Nanoparticles/chemistry ; Methicillin-Resistant Staphylococcus aureus/drug effects/pathogenicity ; Mice ; Polymers/chemistry/pharmacology ; Prostheses and Implants/*microbiology ; Reactive Oxygen Species/metabolism ; Silver/chemistry/pharmacology ; Staphylococcal Infections/microbiology/*prevention & control ; }, abstract = {To prevent infections associated with medical implants, various antimicrobial silver-coated implant materials have been developed. However, these materials do not always provide consistent antibacterial effects in vivo despite having dramatic antibacterial effects in vitro, probably because the antibacterial effects involve silver-ion-mediated reactive oxygen species generation. Additionally, the silver application process often requires extremely high temperatures, which damage non-metal implant materials. We recently developed a bacteria-resistant coating consisting of hydroxyapatite film on which ionic silver is immobilized via inositol hexaphosphate chelation, using a series of immersion and drying steps performed at low heat. Here we applied this coating to a polymer, polyetheretherketone (PEEK), and analyzed the properties and antibacterial activity of the coated polymer in vitro and in vivo. The ionic silver coating demonstrated significant bactericidal activity and prevented bacterial biofilm formation in vitro. Bio-imaging of a soft tissue infection mouse model in which a silver-coated PEEK plate was implanted revealed a dramatic absence of bacterial signals 10 days after inoculation. These animals also showed a strong reduction in histological features of infection, compared to the control animals. This innovative coating can be applied to complex structures for clinical use, and could prevent infections associated with a variety of plastic implants.}, } @article {pmid33573482, year = {2021}, author = {Huang, J and Fan, Q and Guo, M and Wu, M and Wu, S and Shen, S and Wang, X and Wang, H}, title = {Octenidine dihydrochloride treatment of a meticillin-resistant Staphylococcus aureus biofilm-infected mouse wound.}, journal = {Journal of wound care}, volume = {30}, number = {2}, pages = {106-114}, doi = {10.12968/jowc.2021.30.2.106}, pmid = {33573482}, issn = {0969-0700}, mesh = {Animals ; Anti-Infective Agents/*therapeutic use ; Anti-Infective Agents, Local/therapeutic use ; Biofilms ; Imines ; Methicillin ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Mice ; Pyridines/*therapeutic use ; Staphylococcal Infections/*drug therapy ; Wound Healing ; Wound Infection/*drug therapy ; }, abstract = {OBJECTIVE: This study sought to estimate the effect of a liquid octenidine dihydrochloride (OCT)-impregnated gauze dressing in the treatment of meticillin-resistant Staphylococcus aureus (MRSA) biofilm-infected wounds.

METHOD: In this animal study, a six-millimetre punch full-thickness wound on each mouse back was inoculated with MRSA suspension, and then covered with a Tegaderm (3M Health Care, US) dressing for an established biofilm model. Animals were divided into three groups for topical application: control group (treated with phosphate-buffered saline, PBS); mupirocin group (treated with 2% mupirocin); and OCT group (treated with OCT). All applications were administrated once 24 hours post-wounding. The bioburden was determined by counting colony-forming units (cfus) and the biofilm architecture was viewed using fluorescent staining and scanning electron microscopy (SEM) on day two. The tissue repair was evaluated histologically and the related genes were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) on day 15.

RESULTS: The results suggested OCT accelerated healing and reduced by >3.6 log cfu/g bacterial counts on the wounds relative to the PBS-treated control (p<0.05). Histological analysis showed OCT-treated tissue exhibited lower burden of the inflammatory cells, more mature collagen fibres and well-defined epithelialisation. LIVE/DEAD fluorescent staining and SEM confirmed OCT induced a substantial destruction to biofilm structure. RT-qPCR further demonstrated that OCT therapy could inhibit the expression of MRSA and its biofilm genes by nearly 100% (p<0.05).

CONCLUSION: This investigation provides a rare in vivo experimental basis for OCT improvement on MRSA-infected wound healing and the superior efficacy implies OCT topical application may represent an ideal choice to address established bacterial biofilm in hard-to-heal wounds.}, } @article {pmid33573343, year = {2021}, author = {Perveen, K and Husain, FM and Qais, FA and Khan, A and Razak, S and Afsar, T and Alam, P and Almajwal, AM and Abulmeaty, MMA}, title = {Microwave-Assisted Rapid Green Synthesis of Gold Nanoparticles Using Seed Extract of Trachyspermum ammi: ROS Mediated Biofilm Inhibition and Anticancer Activity.}, journal = {Biomolecules}, volume = {11}, number = {2}, pages = {}, pmid = {33573343}, issn = {2218-273X}, support = {RGP-193//Deanship of Scientific Research, King Saud University/ ; }, mesh = {Anisotropy ; Anti-Bacterial Agents/pharmacology ; Antineoplastic Agents/*pharmacology ; Apiaceae/*metabolism ; Biofilms/drug effects ; Cell Survival ; Glutathione Transferase/metabolism ; Gold/*chemistry ; Green Chemistry Technology ; Hep G2 Cells ; Humans ; Light ; Lipid Peroxidation ; Listeria monocytogenes/drug effects ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Microwaves ; Plant Extracts/pharmacology ; Polysaccharides, Bacterial/chemistry ; *Reactive Oxygen Species ; Scattering, Radiation ; Seeds/*metabolism ; Serratia marcescens/drug effects ; Tetrazolium Salts/chemistry ; Thiazoles/chemistry ; X-Ray Diffraction ; }, abstract = {Green synthesis of metal nanoparticles using plant extracts as capping and reducing agents for the biomedical applications has received considerable attention. Moreover, emergence and spread of multidrug resistance among bacterial pathogens has become a major health concern and lookout for novel alternative effective drugs has gained momentum. In current study, we synthesized gold nanoparticles using the seed extract of Trachyspermum ammi (TA-AuNPs), assessed its efficacy against drug resistant biofilms of Listeria monocytogenes and Serratia marcescens, and evaluated its anticancer potential against HepG2 cancer cell lines. Microwave-assisted green synthesis of gold nanoparticles was carried out and characterization was done using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Most nanoparticles were observed as spherical and spheroidal with few anisotropies with an average crystalline size of 16.63 nm. Synthesized TA-AuNPs demonstrated significant biofilm inhibitory activity against L. monocytogenes (73%) as well as S. marcescens (81%). Exopolysaccharide (EPS), motility, and CSH, key elements that facilitate the formation and maintenance of biofilm were also inhibited significantly at the tested sub-minimum inhibitory concentrations (sub-MICs). Further, TA-AuNPs effectively obliterated preformed mature biofilms of S. marcescens and L. monocytogenes by 64% and 58%, respectively. Induction of intracellular ROS production in TA-AuNPs treated bacterial cells could be the plausible mechanism for the reduced biofilm formation in test pathogens. Administration of TA-AuNPs resulted in the arrest of cellular proliferation in a concentration-dependent manner. TA-AuNPs decrease the intracellular GSH in HepG2 cancer cell lines, cells become more prone to ROS generation, hence induce apoptosis. Thus, this work proposes a new eco-friendly and rapid approach for fabricating NPs which can be exploited for multifarious biomedical applications.}, } @article {pmid33573330, year = {2021}, author = {He, X and Li, Q and Wang, N and Chen, S}, title = {Effects of an EPS Biosynthesis Gene Cluster of Paenibacillus polymyxa WLY78 on Biofilm Formation and Nitrogen Fixation under Aerobic Conditions.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33573330}, issn = {2076-2607}, support = {2020SKLAB6-21//Innovative Project of SKLAB/ ; 2019YFA0904700//National Key Research and Development Program of China/ ; }, abstract = {Exopolysaccharides (EPS) are of high significance in bacterial biofilm formation. However, the effects of EPS cluster(s) on biofilm formation in Paenibacillus species are little known. In this study, we have shown that Paenibacillus polymyxa WLY78, a N2-fixing bacterium, can form biofilm. EPS is the major component of the extracellular matrix. The genome of P. polymyxa WLY78 contains two putative gene clusters (designated pep-1 cluster and pep-2 cluster). The pep-1 cluster is composed of 12 putative genes (pepO-lytR) co-located in a 13 kb region. The pep-2 cluster contains 17 putative genes (pepA-pepN) organized as an operon in a 20 kb region. Mutation analysis reveals that the pep-2 cluster is involved in EPS biosynthesis and biofilm formation. Disruption of the pep-2 cluster also leads to the enhancement of motility and change of the colony morphology. In contrast, disruption of the pep-1 cluster does not affect EPS synthesis or biofilm formation. More importantly, the biofilm allowed P. polymyxa WLY78 to fix nitrogen in aerobic conditions, suggesting that biofilm may provide a microaerobic environment for nitrogenase synthesis and activity.}, } @article {pmid33573147, year = {2021}, author = {Parolia, A and Kumar, H and Ramamurthy, S and Madheswaran, T and Davamani, F and Pichika, MR and Mak, KK and Fawzy, AS and Daood, U and Pau, A}, title = {Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {3}, pages = {}, pmid = {33573147}, issn = {1420-3049}, support = {ERGS/1/2013/SKK11/IMU/03/01//Ministry of Higher Education, Malaysia and approved by the joint committee on research and ethics of the University./ ; }, mesh = {Adult ; Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/drug effects ; Dental Pulp Cavity/drug effects/microbiology ; Dentin/microbiology ; Enterococcus faecalis/*drug effects/pathogenicity ; Female ; Humans ; Male ; Microscopy, Confocal ; Molecular Docking Simulation ; Nanoparticles/*chemistry ; Propolis/*administration & dosage/chemistry ; }, abstract = {To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and β-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm[-1] band and an increase in the 870 cm[-1] band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.}, } @article {pmid33572576, year = {2021}, author = {Jung, JI and Baek, SM and Nguyen, TH and Kim, JW and Kang, CH and Kim, S and Imm, JY}, title = {Effects of Probiotic Culture Supernatant on Cariogenic Biofilm Formation and RANKL-Induced Osteoclastogenesis in RAW 264.7 Macrophages.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {3}, pages = {}, pmid = {33572576}, issn = {1420-3049}, support = {R&D, S2908142//Ministry of Small and Medium Sized Enterprises (SMEs) and Startups (MSS), Korea/ ; }, mesh = {Animals ; Biofilms/*drug effects/growth & development ; Cell Differentiation/drug effects ; Heme Oxygenase-1/metabolism ; Ligilactobacillus salivarius/*growth & development ; Macrophages/*cytology ; Membrane Proteins/metabolism ; Mice ; Osteoclasts/cytology/*drug effects ; Osteogenesis/*drug effects ; Probiotics/*pharmacology ; RANK Ligand/pharmacology ; RAW 264.7 Cells ; Streptococcus mutans/drug effects/*physiology ; }, abstract = {Postbiotics are a promising functional ingredient that can overcome the limitations of viability and storage stability that challenge the production of probiotics. To evaluate the effects of postbiotics on oral health, eight spent culture supernatants (SCSs) of probiotics were prepared, and the effects of SCSs on Streptococcus mutans-induced cariogenic biofilm formation and the receptor activator of the nuclear factor κB ligand (RANKL)-induced osteoclastogenesis were evaluated in RAW 264.7 macrophages. SCS of Lactobacillus salivarius MG4265 reduced S. mutans-induced biofilm formation by 73% and significantly inhibited tartrate-resistant acid phosphatase (TRAP) activity, which is a biomarker of mature osteoclasts in RAW 264.7 macrophages. The suppression of RANKL-induced activation of mitogen activated the protein kinases (c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38) and nuclear factor κB pathways, as well as the upregulation of heme oxygenase-1 expression. The suppression of RANK-L-induced activation of mitogen also inhibited the expression of transcriptional factors (c-fos and nuclear factor of activated T cells cytoplasmic 1) and, subsequently, osteoclastogenesis-related gene expression (tartrate-resistant acid phosphatase-positive (TRAP), cathepsin K, and matrix metalloproteinase-9).Therefore, SCS of L. salivarius MG4265 has great potential as a multifunctional oral health ingredient that inhibits biofilm formation and suppresses the alveolar bone loss that is associated with periodontitis.}, } @article {pmid33572192, year = {2021}, author = {Kelar Tučeková, Z and Vacek, L and Krumpolec, R and Kelar, J and Zemánek, M and Černák, M and Růžička, F}, title = {Multi-Hollow Surface Dielectric Barrier Discharge for Bacterial Biofilm Decontamination.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {4}, pages = {}, pmid = {33572192}, issn = {1420-3049}, support = {TJ04000329 and TG02010067//Technology Agency of the Czech Republic/ ; LM2018097//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; }, mesh = {Biofilms/*drug effects ; Decontamination/*methods ; *Electricity ; Escherichia coli/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Viability ; Plasma Gases/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Staphylococcus epidermidis/drug effects ; }, abstract = {The plasma-activated gas is capable of decontaminating surfaces of different materials in remote distances. The effect of plasma-activated water vapor on Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli biofilm contamination was investigated on the polypropylene nonwoven textile surface. The robust and technically simple multi-hollow surface dielectric barrier discharge was used as a low-temperature atmospheric plasma source to activate the water-based medium. The germicidal efficiency of short and long-time exposure to plasma-activated water vapor was evaluated by standard microbiological cultivation and fluorescence analysis using a fluorescence multiwell plate reader. The test was repeated in different distances of the contaminated polypropylene nonwoven sample from the surface of the plasma source. The detection of reactive species in plasma-activated gas flow and condensed activated vapor, and thermal and electrical properties of the used plasma source, were measured. The bacterial biofilm decontamination efficiency increased with the exposure time and the plasma source power input. The log reduction of viable biofilm units decreased with the increasing distance from the dielectric surface.}, } @article {pmid33571768, year = {2021}, author = {Zhou, L and Ou, P and Zhao, B and Zhang, W and Yu, K and Xie, K and Zhuang, WQ}, title = {Assimilatory and dissimilatory sulfate reduction in the bacterial diversity of biofoulant from a full-scale biofilm-membrane bioreactor for textile wastewater treatment.}, journal = {The Science of the total environment}, volume = {772}, number = {}, pages = {145464}, doi = {10.1016/j.scitotenv.2021.145464}, pmid = {33571768}, issn = {1879-1026}, mesh = {Bacteria/genetics ; Biofilms ; *Bioreactors ; Sulfates ; Textiles ; Wastewater ; *Water Purification ; }, abstract = {Assimilatory and dissimilatory sulfate reduction (ASR and DSR) are the core bacterial sulfate-reducing pathways involved in wastewater treatment. It has been reported that sulfate-reducing activities could happen within biofoulants of membrane bioreactors during wastewater treatment. Biofoulants are mainly microbial products contributing membrane fouling and subsequent rising energy consumption in driving membrane filtration. Biofoulants from a full-scale biofilm-membrane bioreactor (biofilm-MBR) treating textile wastewater were investigated in this study. During a 10-month operation, sulfate concentrations in the effluent of the biofilm-MBR gradually decreased alongside with the creeping up sulfite concentrations when biofoulants were also building up on membrane modules. Sulfide had no apparent increases in the effluent during this period. Metagenomic analysis revealed diverse microbial communities residing in the biofoulants. Further analysis on their genetic traits revealed abundant ASR's and DSR's functional genes. A plethora of sulfate-reduction bacteria (SRB), including the well-known Desulfovibrio, Desulfainum, Desulfobacca, Desulfobulbus, Desulfococcus, Desulfonema, Desulfosarcina, Desulfobacter, Desulfobacula, Desulfofaba, Desulfotigum, Desulfatibacillum, Desulfatitalea, Desulfobacterium, were detected in the biofoulants. They were believed to play some important carbon and sulfur-cycling roles in our study. Based on metagenomic analysis, we also deduced that ASR was a functionally more important sulfate-reducing route because of the high abundance of assimilatory sulfate reductases detected. Also, the "AMP (adenosine monophosphate)→sulfite" step was a key reaction shared by both ASR and DSR in the biofoulant. This step might be responsible for the sulfite accumulation in the biofilm-MBR effluent. Overall, ASR functional genes in the biofoulants were more abundant. But the bacteria possessing complete DSR pathways caused the sulfide production in the biofilm-MBR.}, } @article {pmid33571649, year = {2021}, author = {Kamauchi, H and Kimura, Y and Ushiwatari, M and Suzuki, M and Seki, T and Takao, K and Sugita, Y}, title = {Synthesis and antifungal activity of polycyclic pyridone derivatives with anti-hyphal and biofilm formation activity against Candida albicans.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {37}, number = {}, pages = {127845}, doi = {10.1016/j.bmcl.2021.127845}, pmid = {33571649}, issn = {1464-3405}, mesh = {Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects ; Dose-Response Relationship, Drug ; Heterocyclic Compounds/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Pyridones/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Thirty-five pyridone derivatives were synthesized, with derivatization conducted on polycyclic pyridone scaffolds, including cis- or trans-oxydecalin and other cyclic structures, by domino-Knoevenagel-electrocyclic reactions. The anti-fungal activities of the synthesized compounds were tested against Candida albicans. Ten compounds inhibited hyphal formation without inhibiting growth. Pyridones with anti-hyphal formation activity (4c, 6d, 12a and 12c) were tested for their ability to inhibit biofilm formation. Compound 6d showed both anti-hyphal and biofilm inhibition activity.}, } @article {pmid33571231, year = {2021}, author = {Pérez-Calpe, AV and Larrañaga, A and von Schiller, D and Elosegi, A}, title = {Interactive effects of discharge reduction and fine sediments on stream biofilm metabolism.}, journal = {PloS one}, volume = {16}, number = {2}, pages = {e0246719}, pmid = {33571231}, issn = {1932-6203}, mesh = {Biodiversity ; Biofilms/*growth & development ; Biomass ; Chlorophyll A/metabolism ; Chlorophyta/metabolism/*physiology ; Geologic Sediments/analysis/*microbiology ; Rivers/chemistry/*microbiology ; }, abstract = {Discharge reduction, as caused by water diversion for hydropower, and fine sediments deposition, are prevalent stressors that may affect multiple ecosystem functions in streams. Periphytic biofilms play a key role in stream ecosystem functioning and are potentially affected by these stressors and their interaction. We experimentally assessed the interactive effects of discharge and fine sediments on biofilm metabolism in artificial indoor channels using a factorial split-plot design with two explanatory variables: water discharge (20, 39, 62, 141 and 174 cm3 s-1) and fine sediments (no sediment or 1100 mg L-1 of sediments). We incubated artificial tiles for 25 days in an unpolluted stream to allow biofilm colonization, and then placed them into the indoor channels for acclimation for 18 days. Subsequently, we manipulated water discharge and fine sediments and, after 17 days, we measured biofilm chlorophyll-a concentration and metabolism. Water velocity (range, 0.5 to 3.0 cm s-1) and sediment deposition (range, 6.1 to 16.6 mg cm-2) increased with discharge, the latter showing that the effect of increased inputs prevailed over sloughing. In the no-sediment treatments, discharge did not affect biofilm metabolism, but reduced chlorophyll-a. Sediments, probably as a consequence of nutrients released, promoted metabolism of biofilm and chlorophyll-a, which became independent of water discharge. Our results indicate that pulses of fine sediments can promote biofilm algal biomass and metabolism, but show interactive effects with discharge. Although discharge reduction can affect the abundance of basal resources for food webs, its complex interactions with fine sediments make it difficult to forecast the extent and direction of the changes.}, } @article {pmid33568456, year = {2021}, author = {Park, S and Dingemans, J and Gowett, M and Sauer, K}, title = {Glucose-6-Phosphate Acts as an Extracellular Signal of SagS To Modulate Pseudomonas aeruginosa c-di-GMP Levels, Attachment, and Biofilm Formation.}, journal = {mSphere}, volume = {6}, number = {1}, pages = {}, pmid = {33568456}, issn = {2379-5042}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; 2R01 AI080710/AI/NIAID NIH HHS/United States ; }, mesh = {*Bacterial Adhesion ; Bacterial Proteins/*genetics/metabolism ; Biofilms/drug effects/*growth & development ; Cyclic GMP/*analogs & derivatives/analysis/metabolism ; Glucose-6-Phosphate/*metabolism/pharmacology ; Pseudomonas aeruginosa/drug effects/genetics/*metabolism/pathogenicity ; Signal Transduction ; }, abstract = {In Pseudomonas aeruginosa, the orphan two-component sensor SagS contributes both to transition to biofilm formation and to biofilm cells gaining their heightened tolerance to antimicrobials. However, little is known about the identity of the signals or conditions sensed by SagS to induce the switch to the sessile, drug-tolerant mode of growth. Using a modified Biolog phenotype assay to screen for compounds that modulate attachment in a SagS-dependent manner, we identified glucose-6-phosphate to enhance attachment in a manner dependent on the glucose-6-phosphate concentration and SagS. The stimulatory effect was not limited to the attachment since glucose-6-phosphate likewise enhanced biofilm formation and also enhanced the expression of select biofilm marker genes. Moreover, exposure to glucose-6-phosphate coincided with decreased swarming motility but increased cellular cyclic-di-GMP (c-di-GMP) levels in biofilms. No such response was noted for compounds modulating attachment and biofilm formation in a manner independent of SagS. Modulation of c-di-GMP in response to glucose-6-phosphate was due to the diguanylate cyclase NicD, with NicD also being required for enhanced biofilm formation. The latter was independent of the sensory domain of NicD but dependent on NicD activity, SagS, and the interaction between NicD and SagS. Our findings indicate that glucose-6-phosphate likely mimics a signal or conditions sensed by SagS to activate its motile-sessile switch function. In addition, our findings provide new insight into the interfaces between the ligand-mediated two-component system signaling pathway and c-di-GMP levels.IMPORTANCE Pathogens sense and respond to signals and cues present in their environment, including host-derived small molecules to modulate the expression of their virulence repertoire. Here, we demonstrate that the opportunistic pathogen Pseudomonas aeruginosa responds to glucose-6-phosphate. Since glucose-6-phosphate is primarily made available due to cell lysis, it is likely that glucose-6-phosphate represents a cross-kingdom cell-to-cell signal that enables P. aeruginosa to adapt to the (nutrient-poor) host environment by enhancing biofilm formation, cyclic-di-GMP, and the expression of genes linked to biofilm formation in a concentration- and SagS-dependent manner.}, } @article {pmid33568036, year = {2021}, author = {Delfani, S and Rezaei, F and Soroush, S and Shakib, P}, title = {The Staphylococcal Cassette Chromosome mec (SCCmec) Analysis and Biofilm Formation of Methicillin-Resistant Staphylococcus cohnii Isolated from Clinical Samples in Tehran, Iran.}, journal = {Recent patents on anti-infective drug discovery}, volume = {}, number = {}, pages = {}, doi = {10.2174/1574891X16666210210101912}, pmid = {33568036}, issn = {2212-4071}, abstract = {BACKGROUND: Methicillin-resistant coagulase-negative staphylococci is responsible for hospital and community-acquired infections.

OBJECTIVE: This study aimed to investigate the antibiotic-resistance patterns, antibiotic-resistance genes, namely, ermA, ermB, ermC, blaZ, msrA, tetK, tetM, mup, and vanA, biofilm formation, and prevalence of different SCCmec types among the Staphylococcus cohniistrains isolated from clinical samples in Tehran, Iran.

METHODS: In this study,S. cohniiisolates were screened from the clinical samples from March 2012 to February 2013 in Tehran, Iran.Antimicrobial susceptibility test and inducible clindamycin resistance were evaluated by disc diffusion method, andresistance genes were examined using Polymerase Chain Reaction (PCR) assays. Then, biofilm formation assay was analyzed by Microtiter-plate test to detect the icaA and icaDgenes. The SCCmec and the Arginine Catabolite Mobile Element (ACME) typing were performed using the PCRmethod.

RESULTS: FromtwentyS. cohnii, all isolates were resistant to cefoxitin. 95% of the S. cohnii was defined as multidrug resistance (MDR)strains. The ermB, ermC, and vanA genes were not detected in any isolates; however, the blaZ gene had the highest frequency.95% of the S. cohnii isolates produced biofilm. Also, 4 SCCmec types, including V, IV, III+ (C2), VIII+ (AB1), were identified. Therefore, the majority of SCCmec were untypable. Based on the ACME typing, arcA and opp3 genes were positive in 13 (65%) and 1 (5%) isolates, respectively.

CONCLUSION: Due to the high antimicrobial resistance and the spread of untypableSCCmecamong the isolates studied, the control and treatment of methicillin-resistantS. cohnii in hospitals and public health centers is a significant concern.}, } @article {pmid33567279, year = {2021}, author = {Han, C and Song, J and Hu, J and Fu, H and Feng, Y and Mu, R and Xing, Z and Wang, Z and Wang, L and Zhang, J and Wang, C and Dong, L}, title = {Smectite promotes probiotic biofilm formation in the gut for cancer immunotherapy.}, journal = {Cell reports}, volume = {34}, number = {6}, pages = {108706}, doi = {10.1016/j.celrep.2021.108706}, pmid = {33567279}, issn = {2211-1247}, mesh = {Animals ; Bifidobacterium/*physiology ; Biofilms/*drug effects/growth & development ; Cell Line, Tumor ; Female ; Gastrointestinal Microbiome/*drug effects ; *Immunotherapy ; Lactobacillus/*physiology ; Mice ; Mice, Inbred BALB C ; Mice, Knockout ; *Neoplasms, Experimental/microbiology/therapy ; Probiotics/*pharmacology ; Silicates/*pharmacology ; }, abstract = {Administration of probiotics to regulate the immune system is a potential anti-tumor strategy. However, oral administration of probiotics is ineffective because of the poor inhabitation of exogenous bacteria in host intestines. Here we report that smectite, a type of mineral clay and established anti-diarrhea drug, promotes expansion of probiotics (especially Lactobacillus) in the murine gut and subsequently elicits anti-tumor immune responses. The ion-exchangeable microstructure of smectite preferentially promotes lactic acid bacteria (LABs) to form biofilms on smectite in vitro and in vivo. In mouse models, smectite laden with LAB biofilms (Lactobacillus and Bifidobacterium) inhibits tumor growth (when used alone) and enhances the efficacy of chemotherapy or immunotherapy (when used in combination with either of them) by activating dendritic cells (DCs) via Toll-like receptor 2 (TLR2) signaling. Our findings suggest oral administration of smectite as a promising strategy to enrich probiotics in vivo for cancer immunotherapy.}, } @article {pmid33567173, year = {2021}, author = {Chervinets, VM and Chervinets, YV and Leont'eva, AV and Kozlova, EA and Stulov, NM and Belyaev, VS and Grigoryants, EO and Mironov, AY}, title = {The microbiome of oral cavity patients with periodontitis, adhesive and biofilm forming properties.}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {66}, number = {1}, pages = {45-51}, doi = {10.18821/0869-2084-2021-66-1-45-51}, pmid = {33567173}, issn = {0869-2084}, mesh = {*Adhesives ; Adult ; Biofilms ; Humans ; *Microbiota ; Middle Aged ; Periodontal Pocket ; }, abstract = {The microbiome of oral cavity in healthy people and patients with periodontitis was analyzed to determine their adhesive properties and the ability to form biofilms. The study involved 2 groups: healthy, 18 people, and an experimental group, 20 patients with chronic generalized periodontitis moderate severity of the disease. The average age of the studied people was 35-45 years. Material - dental plaque, scraping from the mucous membrane of the back of the tongue, the contents of the periodontal groove and periodontal pocket, as well as oral fluid. The main method of diagnostic was bacteriological. The average adhesion index (AAI) was used to determine adhesion level of microorganisms to epithelial cells of oral cavity's mucous membrane. The microbiota's ability to form biofilm was tested on glass and plastic surface. The microbiota of oral cavity of patients with periodontitis was characterized by decrease in the frequency of bacteria of the genera: Streptococcus, Peptostreptococcus, Peptococcus, and an increase in Staphylococcus aureus, Veillonella spp., Bacillus spp. The microbiota of the oral cavity of patients with generalized periodontitis has a greater ability to adhere to the cells of the mucous membrane than in healthy people, while their ability to form biofilms and exhibit pathogenic properties is enhanced. The biofilm formation of microorganisms in healthy and sick people differs both on glass and on plastic surfaces.}, } @article {pmid33563031, year = {2021}, author = {Ugya, YA and Hasan, DB and Tahir, SM and Imam, TS and Ari, HA and Hua, X}, title = {Microalgae biofilm cultured in nutrient-rich water as a tool for the phycoremediation of petroleum-contaminated water.}, journal = {International journal of phytoremediation}, volume = {23}, number = {11}, pages = {1175-1183}, doi = {10.1080/15226514.2021.1882934}, pmid = {33563031}, issn = {1549-7879}, mesh = {Biodegradation, Environmental ; Biofilms ; *Microalgae ; Nutrients ; *Petroleum ; Water ; Water Pollution ; }, abstract = {This study aimed at studying the phycoremediation of petroleum-contaminated water using microalgae biofilm cultured in nutrient-rich water. Microalgae biofilm was grown in a photobioreactor containing water rich in calcium nitrate, manganese chloride, sodium potassium tartrate, calcium phosphate, and ammonium sulfate. Petroleum contaminated water was poured into a photobioreactor, and the substrate containing microalgae biofilm was inserted into the photobioreactor and allowed for eight weeks for biofilm formation. Physicochemical parameters (pH, turbidity, conductivity, sulfate, alkalinity, chloride, TDS, TSS, nitrate, salinity, iron, potassium, phosphate, chlorine, chromium, magnesium, zinc, COD, BOD, and total petroleum hydrocarbon (TPH) of the petroleum contaminated water before and after treatment were determined. The microalgae biofilm used for the treatment was characterized before and after treatment using a Scanning Electron Microscope, X-Ray Fluorescence, and Fourier-transform infrared spectroscopy. The phytochemical constituent of the microalgae biofilm was also determined before and after treatment of the petroleum-contaminated water. The result obtained shows highest removal efficiency of physicochemical parameters (turbidity (81%), conductivity (51.2), sulfate (17.5%), alkalinity 28.4%), chloride (14.6%), TDS (7.9), TSS (26%), nitrate (33%), salinity (23.4), iron (16%), potassium (22%), phosphate (28.2%), chlorine (14%), chromium (13.6%), magnesium (30.3%), zinc (40.5%), COD (8%), BOD (16.7%) and total petroleum hydrocarbon (15%)). The microalgae's characterization shows microalgae biofilm's ability to adsorb pollutants in petroleum-contaminated water due to the presence of microspores and larger surface area of the cells of the microalgae forming the biofilm or due to the absorption efficiency of the extracellular polymeric substances (EPS). The analysis of the microalgae biofilm's phytochemical parameters shows the involvement of the chemicals components in pollutants degradation and antioxidant response of the microalgae to counteract the oxidative effect resulting from the exposure of the microalgae to the contaminated water. NOVELTY STATEMENT This is the first study that attempts the phycoremediation of petroleum contaminated water using microalgae biofilm. The reduction efficiency of the parameters treated in this study is very low compared to that reported in the literature but increases with the retention day. This low reduction efficiency is attributed to the slow assimilation of organic and inorganic pollutants due to the initial growth condition. This study is the first to re-affirm that microalgae biofilm can phycoremediate petroleum-contaminated water by adsorption and assimilation due to the presence of microspores and a larger surface area the cells of the microalgae forming the biofilm or the extracellular polymetric surface covering the biofilm. Several studies have reported that phytochemicals present in microalgae play an antioxidant response role to prevent the microalgae from oxidative damage resulting from water pollution. However, this study is the first to strongly link phytochemicals to the enhancement of pollutants degradation and adsorption by microalgae biofilm.}, } @article {pmid33562821, year = {2021}, author = {Renz, N and Trampuz, A and Zimmerli, W}, title = {Controversy about the Role of Rifampin in Biofilm Infections: Is It Justified?.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33562821}, issn = {2079-6382}, abstract = {Rifampin is a potent antibiotic against staphylococcal implant-associated infections. In the absence of implants, current data suggest against the use of rifampin combinations. In the past decades, abundant preclinical and clinical evidence has accumulated supporting its role in biofilm-related infections.In the present article, experimental data from animal models of foreign-body infections and clinical trials are reviewed. The risk for emergence of rifampin resistance and multiple drug interactions are emphasized. A recent randomized controlled trial (RCT) showing no beneficial effect of rifampin in patients with acute staphylococcal periprosthetic joint infection treated with prosthesis retention is critically reviewed and data interpreted. Given the existing strong evidence demonstrating the benefit of rifampin, the conduction of an adequately powered RCT with appropriate definitions and interventions would probably not comply with ethical standards.}, } @article {pmid33562704, year = {2021}, author = {Zhao, N and Mou, H and Zhou, Y and Ju, X and Yang, S and Liu, S and Dong, R}, title = {Upgrading Solid Digestate from Anaerobic Digestion of Agricultural Waste as Performance Enhancer for Starch-Based Mulching Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {4}, pages = {}, pmid = {33562704}, issn = {1420-3049}, support = {U20A2086//National Natural Science Foundation of China/ ; 2020IM020900//Special Project on Innovation Methodology, Ministry of Science and Technology of China/ ; 2019XDRHXMXK25//Yantai Educational-Local Synthetic Development Project/ ; 2019XDRHXMQT36//Yantai Educational-Local Synthetic Development Project/ ; }, mesh = {*Agriculture ; Anaerobiosis ; *Biofilms ; Bioreactors/*microbiology ; Mechanical Phenomena ; Temperature ; *Waste Products ; }, abstract = {Developing a green and sustainable method to upgrade biogas wastes into high value-added products is attracting more and more public attention. The application of solid residues as a performance enhancer in the manufacture of biofilms is a prospective way to replace conventional plastic based on fossil fuel. In this work, solid digestates from the anaerobic digestion of agricultural wastes, such as straw, cattle and chicken manures, were pretreated by an ultrasonic thermo-alkaline treatment to remove the nonfunctional compositions and then incorporated in plasticized starch paste to prepare mulching biofilms by the solution casting method. The results indicated that solid digestate particles dispersed homogenously in the starch matrix and gradually aggregated under the action of a hydrogen bond, leading to a transformation of the composites to a high crystalline structure. Consequently, the composite biofilm showed a higher tensile strength, elastic modulus, glass transition temperature and degradation temperature compared to the pure starch-based film. The light, water and GHG (greenhouse gas) barrier properties of the biofilm were also reinforced by the addition of solid digestates, performing well in sustaining the soil quality and minimizing N2O or CH4 emissions. As such, recycling solid digestates into a biodegradable plastic substitute not only creates a new business opportunity by producing high-performance biofilms but also reduces the environmental risk caused by biogas waste and plastics pollution.}, } @article {pmid33562515, year = {2021}, author = {Gherasim, O and Grumezescu, AM and Grumezescu, V and Negut, I and Dumitrescu, MF and Stan, MS and Nica, IC and Holban, AM and Socol, G and Andronescu, E}, title = {Bioactive Coatings Based on Hydroxyapatite, Kanamycin, and Growth Factor for Biofilm Modulation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33562515}, issn = {2079-6382}, support = {16N/2019//Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii/ ; }, abstract = {The occurrence of opportunistic local infections and improper integration of metallic implants results in severe health conditions. Protective and tunable coatings represent an attractive and challenging selection for improving the metallic devices' biofunctional performances to restore or replace bone tissue. Composite materials based on hydroxyapatite (HAp), Kanamycin (KAN), and fibroblast growth factor 2 (FGF2) are herein proposed as multifunctional coatings for hard tissue implants. The superior cytocompatibility of the obtained composite coatings was evidenced by performing proliferation and morphological assays on osteoblast cell cultures. The addition of FGF2 proved beneficial concerning the metabolic activity, adhesion, and spreading of cells. The KAN-embedded coatings exhibited significant inhibitory effects against bacterial biofilm development for at least two days, the results being superior in the case of Gram-positive pathogens. HAp-based coatings embedded with KAN and FGF2 protein are proposed as multifunctional materials with superior osseointegration potential and the ability to reduce device-associated infections.}, } @article {pmid33562194, year = {2021}, author = {Szczypta, A and Talaga-Ćwiertnia, K and Kielar, M and Krzyściak, P and Gajewska, A and Szura, M and Bulanda, M and Chmielarczyk, A}, title = {Investigation of Acinetobacter baumannii Activity in Vascular Surgery Units through Epidemiological Management Based on the Analysis of Antimicrobial Resistance, Biofilm Formation and Genotyping.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {4}, pages = {}, pmid = {33562194}, issn = {1660-4601}, mesh = {*Acinetobacter Infections/drug therapy/epidemiology ; *Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Cross Infection/drug therapy/epidemiology ; Drug Resistance, Bacterial/genetics ; Drug Resistance, Multiple, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; beta-Lactamases/genetics ; }, abstract = {BACKGROUND/OBJECTIVES: The genus Acinetobacter demonstrates resistance to antibiotics and has been shown to spread in the hospital environment causing epidemic outbreaks among hospitalized patients. The objectives of the present study was to investigate the antibiotic resistance, biofilm formation, and clonality among Acinetobacter baumannii strains.

MATERIALS AND METHODS: The study involved 6 (I Outbreak) and 3 (II Outbreak) A. baumannii strains isolated from patients hospitalized in vascular surgery unit.

RESULTS: All tested A. baumannii strains were extensively drug resistant (XDR) and all the isolates were carbapenem-resistant and among them, all carried the blaOXA-51 gene, the blaOXA-24 gene, as well as the blaOXA-23 gene. All of the investigated strains had the ability to form a biofilm, but all of them produced less biofilm than the reference strain. Multi-locus sequence typing (MLST) showed that all strains belonged to the ST2 clone. Pulsed-field gel electrophoresis (PFGE) divided the tested outbreak strains into two clones (A and B).

CONCLUSION: This study shows a nosocomial spread of XDR A. baumannii ST2 having the blaOXA-51 gene, the blaOXA-24 gene, as well as the blaOXA-23 gene, low biofilm formers, that was prevalent in the vascular surgery unit. To identify the current situation of vascular surgery departments targeted epidemiological investigation was needed. Effective implementation of infection control prevented the spread of the epidemic outbreaks.}, } @article {pmid33560202, year = {2021}, author = {Juvêncio da Silva, L and Dias Barroso, FD and Vieira, LS and Carlos Mota, DR and da Silva Firmino, BK and Rocha da Silva, C and de Farias Cabral, VP and Cândido, TM and Sá, LGDAV and Barbosa da Silva, WM and Silva, J and Marinho, ES and Cavalcanti, BC and de Moraes, MO and Júnior, HVN and de Andrade Neto, JB}, title = {Diazepam's antifungal activity in fluconazole-resistant Candida spp. and biofilm inhibition in C. albicans: evaluation of the relationship with the proteins ALS3 and SAP5.}, journal = {Journal of medical microbiology}, volume = {70}, number = {3}, pages = {}, doi = {10.1099/jmm.0.001308}, pmid = {33560202}, issn = {1473-5644}, mesh = {Antifungal Agents/*pharmacology ; Aspartic Acid Endopeptidases/metabolism ; Biofilms/*drug effects ; Candida/*drug effects/pathogenicity ; Diazepam/*pharmacology ; Drug Resistance, Fungal/*drug effects ; Fluconazole/pharmacology ; Fungal Proteins/metabolism ; }, abstract = {The genus Candida spp. has been highlighted as one of the main etiological agents causing fungal infections, with Candida albicans being the most prominent, responsible for most cases of candidemia. Due to its capacity for invasion and tissue adhesion, it is associated with the formation of biofilms, mainly in the environment and hospital devices, decreasing the effectiveness of available treatments. The repositioning of drugs, which is characterized by the use of drugs already on the market for other purposes, together with molecular-docking methods can be used aiming at the faster development of new antifungals to combat micro-organisms. This study aimed to evaluate the antifungal effect of diazepam on mature C. albicans biofilms in vitro and its action on biofilm in formation, as well as its mechanism of action and interaction with structures related to the adhesion of C. albicans, ALS3 and SAP5. To determine the MIC, the broth microdilution test was used according to protocol M27-A3 (CLSI, 2008). In vitro biofilm formation tests were performed using 96-well plates, followed by molecular-docking protocols to analyse the binding agent interaction with ALS3 and SAP5 targets. The results indicate that diazepam has antimicrobial activity against planktonic cells of Candida spp. and C. albicans biofilms, interacting with important virulence factors related to biofilm formation (ALS3 and SAP5). In addition, treatment with diazepam triggered a series of events in C. albicans cells, such as loss of membrane integrity, mitochondrial depolarization and increased production of EROs, causing DNA damage and consequent cell apoptosis.}, } @article {pmid33558775, year = {2020}, author = {Ersoy Çallıoğlu, E and Berçin, S and Başdemir, G and Kiriş, M and Tatar, İ and Tuzuner, A and Oğuzhan, T and Müderris, T and Sargon, MF and Korkmaz, MH}, title = {The effect of N-acetyl cysteine on biofilm layers in an experimental model of chronic otitis media.}, journal = {Acta otorhinolaryngologica Italica : organo ufficiale della Societa italiana di otorinolaringologia e chirurgia cervico-facciale}, volume = {40}, number = {6}, pages = {457-462}, pmid = {33558775}, issn = {1827-675X}, mesh = {Acetylcysteine/pharmacology ; Animals ; Biofilms ; Humans ; Models, Theoretical ; *Otitis Media/drug therapy ; *Otitis Media, Suppurative ; Rats ; }, abstract = {OBJECTIVE: The aim of this study was to investigate the efficacy of N-acetylcysteine (NAC) on biofilm layers and on the course of disease in chronic otitis media.

METHODS: Twenty-five rats that were induced with chronic otitis media (COM) were separated into three groups. In Group 1 (N = 18), 0.2% ciprofloxacin + 0.1% dexamethasone sodium phosphate + 0.5 mg/ml NAC solution was locally injected to the right ear of the rats; in Group 2, (N=18) 0.2% ciprofloxacin + 0.1% dexamethasone sodium phosphate was locally injected to the left ear of the rats. No treatment was applied to either ear of rats in Group 3 (N = 5). Histopathological and scanning electron microscope (SEM) evaluations were performed in all groups.

RESULTS: SEM revealed biofilm formation in all COM induced groups. No significant difference was seen between groups 1 and 2 in terms of suppuration levels, fibrosis, inner ear involvement, infection staging and biofilm formation (p > 0.05).

CONCLUSIONS: In this study, while histopathological and SEM evaluation revealed no effect of 0.5 mg/ml NAC on the biofilm layer in COM-induced rats, further studies with NAC at different concentrations are still needed on different types of experimental animals.}, } @article {pmid33558686, year = {2021}, author = {Song, W and Wemheuer, B and Steinberg, PD and Marzinelli, EM and Thomas, T}, title = {Contribution of horizontal gene transfer to the functionality of microbial biofilm on a macroalgae.}, journal = {The ISME journal}, volume = {15}, number = {3}, pages = {807-817}, pmid = {33558686}, issn = {1751-7370}, mesh = {Bacteria/genetics ; Biofilms ; *Gene Transfer, Horizontal ; Plankton ; *Seaweed ; }, abstract = {Horizontal gene transfer (HGT) is thought to be an important driving force for microbial evolution and niche adaptation and has been show in vitro to occur frequently in biofilm communities. However, the extent to which HGT takes place and what functions are being transferred in more complex and natural biofilm systems remains largely unknown. To address this issue, we investigated here HGT and enrichment of gene functions in the biofilm community of the common kelp (macroalgae) Ecklonia radiata in comparison to microbial communities in the surrounding seawater. We found that HGTs in the macroalgal biofilms were dominated by transfers between bacterial members of the same class or order and frequently involved genes for nutrient transport, sugar and phlorotannin degradation as well as stress responses, all functions that would be considered beneficial for bacteria living in this particular niche. HGT did not appear to be driven by mobile gene elements, indicating rather an involvement of unspecific DNA uptake (e.g. natural transformation). There was also a low overlap between the gene functions subject to HGT and those enriched in the biofilm community in comparison to planktonic community members. This indicates that much of the functionality required for bacteria to live in an E. radiata biofilm might be derived from vertical or environmental transmissions of symbionts. This study enhances our understanding of the relative role of evolutionary and ecological processes in driving community assembly and genomic diversity of biofilm communities.}, } @article {pmid33558519, year = {2021}, author = {Bai, X and Liu, D and Xu, L and Tenguria, S and Drolia, R and Gallina, NLF and Cox, AD and Koo, OK and Bhunia, AK}, title = {Biofilm-isolated Listeria monocytogenes exhibits reduced systemic dissemination at the early (12-24 h) stage of infection in a mouse model.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {18}, pmid = {33558519}, issn = {2055-5008}, mesh = {Animals ; Bacterial Adhesion ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Caco-2 Cells ; Disease Models, Animal ; Female ; Food Microbiology ; Gene Expression Regulation, Bacterial ; Humans ; Listeria monocytogenes/genetics/*pathogenicity ; Listeriosis/*microbiology ; Male ; Mice ; Mice, Inbred C57BL ; Virulence Factors/*genetics ; }, abstract = {Environmental cues promote microbial biofilm formation and physiological and genetic heterogeneity. In food production facilities, biofilms produced by pathogens are a major source for food contamination; however, the pathogenesis of biofilm-isolated sessile cells is not well understood. We investigated the pathogenesis of sessile Listeria monocytogenes (Lm) using cell culture and mouse models. Lm sessile cells express reduced levels of the lap, inlA, hly, prfA, and sigB and show reduced adhesion, invasion, translocation, and cytotoxicity in the cell culture model than the planktonic cells. Oral challenge of C57BL/6 mice with food, clinical, or murinized-InlA (InlA[m]) strains reveals that at 12 and 24 h post-infection (hpi), Lm burdens are lower in tissues of mice infected with sessile cells than those infected with planktonic cells. However, these differences are negligible at 48 hpi. Besides, the expressions of inlA and lap mRNA in sessile Lm from intestinal content are about 6.0- and 280-fold higher than the sessle inoculum, respectively, suggesting sessile Lm can still upregulate virulence genes shortly after ingestion (12 h). Similarly, exposure to simulated gastric fluid (SGF, pH 3) and intestinal fluid (SIF, pH 7) for 13 h shows equal reduction in sessile and planktonic cell counts, but induces LAP and InlA expression and pathogenic phenotypes. Our data show that the virulence of biofilm-isolated Lm is temporarily attenuated and can be upregulated in mice during the early stage (12-24 hpi) but fully restored at a later stage (48 hpi) of infection. Our study further demonstrates that in vitro cell culture assay is unreliable; therefore, an animal model is essential for studying the pathogenesis of biofilm-isolated bacteria.}, } @article {pmid33556197, year = {2021}, author = {Guedes, GMM and Santos-Filho, ASP and Regis, WFM and Ocadaque, CJ and Amando, BR and Sidrim, JJC and Brilhante, RSN and Cordeiro, RA and Bandeira, SP and Rocha, MFG and Castelo-Branco, DSCM}, title = {Ex situ model of biofilm-associated wounds: providing a host-like environment for the study of Staphylococcus aureus and Pseudomonas aeruginosa biofilms.}, journal = {Journal of applied microbiology}, volume = {131}, number = {3}, pages = {1487-1497}, doi = {10.1111/jam.15026}, pmid = {33556197}, issn = {1365-2672}, support = {436382/2018-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Animals ; *Biofilms ; In Vitro Techniques ; Pseudomonas Infections ; *Pseudomonas aeruginosa/growth & development/pathogenicity ; Skin/*microbiology ; Staphylococcal Infections ; *Staphylococcus aureus/growth & development/pathogenicity ; Swine ; Wounds and Injuries/microbiology ; }, abstract = {AIM: This study aimed to assess an ex situ model of biofilm-associated wounds on porcine skin for the study of Staphylococcus aureus and Pseudomonas aeruginosa biofilms in a host-like environment, after 48 to 120 h of incubation.

MATERIAL AND RESULTS: Ex situ and in vitro biofilms were comparatively analysed. Overall, CFU-counts and matrix quantification yielded significantly (P < 0·05) higher results for ex situ than in vitro biofilms. Confocal microscopy revealed greater (P < 0·05) biomass and thickness at 48-72 h and greater (P < 0·05) robustness at 72 h of growth. S. aureus ex situ biofilms produced less (P < 0·05) siderophore and proteases than in vitro biofilms, while P. aeruginosa ex situ biofilms produced more (P < 0·05) siderophores and less proteases than in vitro biofilms.

CONCLUSIONS: Biofilms grown ex situ present a greater amount of bacterial cells and polymeric matrix than their in vitro counterparts, reaching maturity at 72 h of growth. Moreover the production of virulence factors differs between ex situ and in vitro biofilms.

These findings emphasize the importance of using ex situ biofilm models, once they mimic in vivo conditions. The use of these models brings perspectives for the pursuit of therapeutic alternatives, as tests may be performed in a host-like environment.}, } @article {pmid33556134, year = {2021}, author = {Wang, N and Qi, F and Yu, H and Yestrepsky, BD and Larsen, SD and Shi, H and Ji, J and Anderson, DW and Li, H and Sun, H}, title = {Physicochemical properties and formulation development of a novel compound inhibiting Staphylococcus aureus biofilm formation.}, journal = {PloS one}, volume = {16}, number = {2}, pages = {e0246408}, pmid = {33556134}, issn = {1932-6203}, support = {T32 GM007767/GM/NIGMS NIH HHS/United States ; }, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms/drug effects/growth & development ; Staphylococcus aureus/*drug effects ; Virulence Factors/metabolism ; }, abstract = {The emergence of antibiotic resistance over the past several decades has given urgency to new antibacterial strategies that apply less selective pressure. A new class of anti-virulence compounds were developed that are active against methicillin-resistant Staphylococcus aureus (MRSA), by inhibiting bacterial virulence without hindering their growth to reduce the selective pressure for resistance development. One of the compounds CCG-211790 has demonstrated potent anti-biofilm activity against MRSA. This new class of anti-virulence compounds inhibited the gene expression of virulence factors involved in biofilm formation and disrupted the biofilm structures. In this study, the physicochemical properties of CCG-211790, including morphology, solubility in pure water or in water containing sodium dodecyl sulfate, solubility in organic solvents, and stability with respect to pH were investigated for the first time. Furthermore, a topical formulation was developed to enhance the therapeutic potential of the compound. The formulation demonstrated acceptable properties for drug release, viscosity, pH, cosmetic elegance and stability of over nine months.}, } @article {pmid33555340, year = {2021}, author = {Gonçalves, B and Azevedo, N and Osório, H and Henriques, M and Silva, S}, title = {Revealing Candida glabrata biofilm matrix proteome: global characterization and pH response.}, journal = {The Biochemical journal}, volume = {478}, number = {4}, pages = {961-974}, doi = {10.1042/BCJ20200844}, pmid = {33555340}, issn = {1470-8728}, mesh = {*Biofilms ; Candida glabrata/drug effects/genetics/*metabolism/pathogenicity ; Carbohydrate Metabolism ; Cell Adhesion ; Computational Biology ; Culture Media/pharmacology ; Fungal Proteins/*isolation & purification ; Gene Expression Regulation, Fungal ; *Hydrogen-Ion Concentration ; Protein Interaction Mapping ; *Proteome ; Transcription Factors/metabolism ; Virulence ; }, abstract = {Candida glabrata is a clinically relevant human pathogen with the ability to form high recalcitrant biofilms that contribute to the establishment and persistence of infection. A defining trait of biofilms is the auto-produced matrix, which is suggested to have structural, virulent and protective roles. Thus, elucidation of matrix components, their function and modulation by the host environment is crucial to disclose their role in C. glabrata pathogenesis. As a major step toward this end, this study aimed to reveal, for the first time, the matrix proteome of C. glabrata biofilms, to characterize it with bioinformatic tools and to study its modulation by the environmental pH (acidic and neutral). The results showed the presence of several pH-specific matrix proteins (51 acidic- and 206 neutral-specific) and also proteins commonly found at both pH conditions (236). Of note, several proteins related to mannan and β-glucan metabolism, which have a potential role in the delivery/organization of carbohydrates in the matrix, were found in both pH conditions but in much higher quantity under the neutral environment. Additionally, several virulence-related proteins, including epithelial adhesins, yapsins and moonlighting enzymes, were found among matrix proteins. Importantly, several proteins seem to have a non-canonical secretion pathway and Pdr1 was found to be a potential regulator of matrix proteome. Overall, this study indicates a relevant impact of environmental cues in the matrix proteome and provides a unique resource for further functional investigation of matrix proteins, contributing to the identification of potential targets for the development of new therapies against C. glabrata biofilms.}, } @article {pmid33553350, year = {2021}, author = {Lei, Y and Xu, Y and Jing, P and Xiang, B and Che, K and Shen, J and Ning, M and Chen, Y and Huang, Y}, title = {The effects of TGF-β1 on staphylococcus epidermidis biofilm formation in a tree shrew biomaterial-centered infection model.}, journal = {Annals of translational medicine}, volume = {9}, number = {1}, pages = {57}, pmid = {33553350}, issn = {2305-5839}, abstract = {BACKGROUND: Transforming growth factor-β1 (TGF-β1) has a wide range of biological functions. It antagonizes lymphocyte response, inhibits pro-inflammatory cytokines, and serves as a signal to turn off the immune response and inflammatory response. To study the correlation between TGF-β1 and T helper (Th)1/Th2 cytokine levels in tree shrews, and to explore the effects of different levels of TGF-β1 on central venous catheter (CVC)-centered Staphylococcus epidermidis biofilm formation in tree shrews.

METHODS: Tree shrews were injected with different concentrations of TGF-β1, and venous blood was drawn after 48 h to measure the levels of Th1 and Th2 cytokines. A CVC was placed into the femoral vein, and TGF-β1 at different concentrations and PIA- (ATCC12228) and PIA+ (ATCC35984) standard strains of Staphylococcus epidermidis were injected into the tree shrews to establish a biomaterial-centered infection (BCI) model. After 72 h, the CVC was removed, and biofilm formation was detected using the API bacterial identification system, semi-quantitative biofilm formation assay, and scanning electron microscopy.

RESULTS: In the groups treated with TGF-β1 at different concentrations, the levels of Th1 cytokines interleukin-2 (IL-2), tumor necrosis factor (TNF), and interferon-γ (IFN-γ) were lower than those of normal group, while the levels of Th2 cytokines IL-6, IL-4 and IL-10 were higher than those of normal group. In the TGF-β1 groups at different concentrations, the positive rate of Staphylococcus epidermidis ATCC35984 biofilm formation was higher than that in non-TGF-β1 group, while there was no significant difference in the positive rate of Staphylococcus epidermidis ATCC12228 biofilm formation compared with that of the non-TGF-β1 group.

CONCLUSIONS: TGF-β1 causes the imbalance of Th1/Th2 cytokines and Th1/Th2 shift in tree shrews, leading to Th1 cell-led decline in cellular immune function. TGF-β1 promotes PIA+ Staphylococcus epidermidis biofilm formation in the tree shrew BCI model, but it has no significant influence on PIA-Staphylococcus epidermidis biofilm formation on the surface of CVCs.}, } @article {pmid33553152, year = {2020}, author = {Tits, J and Berman, J and Cammue, BPA and Thevissen, K}, title = {Combining Miconazole and Domiphen Bromide Results in Excess of Reactive Oxygen Species and Killing of Biofilm Cells.}, journal = {Frontiers in cell and developmental biology}, volume = {8}, number = {}, pages = {617214}, pmid = {33553152}, issn = {2296-634X}, abstract = {Fungal biofilm-related infections are increasingly occurring. We previously identified a fungicidal antibiofilm combination, consisting of miconazole (MCZ) and the quaternary ammonium compound domiphen bromide (DB). DB eliminates tolerance rather than altering the susceptibility to MCZ of various Candida spp. Here we studied the mode of action of the MCZ-DB combination in more detail. We found that DB's action increases the permeability of the plasma membrane as well as that of the vacuolar membrane of Candida spp. Furthermore, the addition of DB affects the intracellular azole distribution. MCZ is a fungicidal azole that, apart from its well-known inhibition of ergosterol biosynthesis, also induces accumulation of reactive oxygen species (ROS). Interestingly, the MCZ-DB combination induced significantly more ROS in C. albicans biofilms as compared to single compound treatment. Co-administration of the antioxidant ascorbic acid resulted in abolishment of the ROS generated by MCZ-DB combination as well as its fungicidal action. In conclusion, increased intracellular MCZ availability due to DB's action results in excess of ROS and enhanced fungal cell killing.}, } @article {pmid33553002, year = {2020}, author = {Fregonezi, NF and Oliveira, LT and Singulani, JL and Marcos, CM and Dos Santos, CT and Taylor, ML and Mendes-Giannini, MJS and de Oliveira, HC and Fusco-Almeida, AM}, title = {Heat Shock Protein 60, Insights to Its Importance in Histoplasma capsulatum: From Biofilm Formation to Host-Interaction.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {591950}, pmid = {33553002}, issn = {2235-2988}, mesh = {Animals ; Antibodies, Monoclonal ; Biofilms ; *Chaperonin 60/genetics ; *Histoplasma ; Macrophages ; Mice ; }, abstract = {Heat shock proteins (Hsps) are among the most widely distributed and evolutionary conserved proteins, acting as essential regulators of diverse constitutive metabolic processes. The Hsp60 of the dimorphic fungal Histoplasma capsulatum is the major surface adhesin to mammalian macrophages and studies of antibody-mediated protection against H. capsulatum have provided insight into the complexity involving Hsp60. However, nothing is known about the role of Hsp60 regarding biofilms, a mechanism of virulence exhibited by H. capsulatum. Considering this, the present study aimed to investigate the influence of the Hsp60 on biofilm features of H. capsulatum. Also, the non-conventional model Galleria mellonella was used to verify the effect of this protein during in vivo interaction. The use of invertebrate models such as G. mellonella is highly proposed for the evaluation of pathogenesis, immune response, virulence mechanisms, and antimicrobial compounds. For that purpose, we used a monoclonal antibody (7B6) against Hsp60 and characterized the biofilm of two H. capsulatum strains by metabolic activity, biomass content, and images from scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). We also evaluated the survival rate of G. mellonella infected with both strains under blockage of Hsp60. The results showed that mAb 7B6 was effective to reduce the metabolic activity and biomass of both H. capsulatum strains. Furthermore, the biofilms of cells treated with the antibody were thinner as well as presented a lower amount of cells and extracellular polymeric matrix compared to its non-treated controls. The blockage of Hsp60 before fungal infection of G. mellonella larvae also resulted in a significant increase of the larvae survival compared to controls. Our results highlight for the first time the importance of the Hsp60 protein to the establishment of the H. capsulatum biofilms and the G. mellonella larvae infection. Interestingly, the results with Hsp60 mAb 7B6 in this invertebrate model suggest a pattern of fungus-host interaction different from those previously found in a murine model, which can be due to the different features between insect and mammalian immune cells such as the absence of Fc receptors in hemocytes. However further studies are needed to support this hypothesis.}, } @article {pmid33552621, year = {2021}, author = {Lee, JE and Lee, NK and Paik, HD}, title = {Antimicrobial and anti-biofilm effects of probiotic Lactobacillus plantarum KU200656 isolated from kimchi.}, journal = {Food science and biotechnology}, volume = {30}, number = {1}, pages = {97-106}, pmid = {33552621}, issn = {2092-6456}, abstract = {The probiotic properties and anti-pathogenic effects of Lactobacillus plantarum KU200656 (KU200656) isolated from Korean fermented kimchi against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella Typhimurium were investigated. KU200656 showed high tolerance to artificial gastric acid (99.48%) and bile salts (102.40%) and this strain was safe according to antibiotic sensitivity test; it could not produce harmful enzymes, including β-glucuronidase. KU200656 exhibited high adhesion (4.45%) to intestinal cells, HT-29 cells, with high cell surface hydrophobicity (87.31% for xylene and 81.11% for toluene). Moreover, KU200656 co-aggregated with pathogenic bacteria and exhibited antibacterial activity and anti-adhesion properties against pathogens. The cell-free supernatant (CFS) of KU200656 inhibited biofilm formation by pathogenic bacteria. In addition, half of the minimum inhibitory concentration of the KU200656 CFS downregulated the expression of biofilm-related genes, as determined by quantitative real-time PCR. Therefore, KU200656 was demonstrated to possess anti-pathogenic effects and have potential for use as probiotics in the food industry.}, } @article {pmid33549827, year = {2021}, author = {Simões, M and Pereira, AR and Simões, LC and Cagide, F and Borges, F}, title = {Biofilm control by ionic liquids.}, journal = {Drug discovery today}, volume = {26}, number = {6}, pages = {1340-1346}, doi = {10.1016/j.drudis.2021.01.031}, pmid = {33549827}, issn = {1878-5832}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; Ionic Liquids/*pharmacology ; }, abstract = {Ionic liquids (ILs) are remarkable chemical compounds with applications in many areas of modern science. They are increasingly recognized as promising compounds to fight microorganisms in both planktonic and biofilm states, contributing to reinvent the antimicrobial pipeline. Biofilm-related infections are particularly challenging given that the scientific community has not yet identified a reliable control strategy. Understanding of the action of ILs in biofilm control is is still in a very early stage. However, given the highly tunable nature and exceptional properties of ILs, they are excellent candidates for biofilm control. Here, we review the major advances in, and challenges tothe use of ILs for effective biofilm control.}, } @article {pmid33549616, year = {2021}, author = {Chen, R and Zhou, Y}, title = {Measure microbial activity driven oxygen transfer in membrane aerated biofilm reactor from supply side.}, journal = {Environmental research}, volume = {195}, number = {}, pages = {110845}, doi = {10.1016/j.envres.2021.110845}, pmid = {33549616}, issn = {1096-0953}, mesh = {*Ammonium Compounds ; Biofilms ; *Bioreactors ; Membranes, Artificial ; Nitrogen ; Oxygen ; Waste Disposal, Fluid ; }, abstract = {This short communication demonstrates for the first time a solely microbial activity driven oxygen influx across a microporous hollow fibre membrane via tracking changes in volume and gas composition of entrapped air supply. A U-shape manometer was used to directly reflect gas influx due to microbial activities. A pressure difference of several hundred pascal was created to draw oxygen while 25 mg-N/L of ammonium was oxidized into nitrite by active biofilm at a hydraulic retention time of 6 h. Calibrated and normalized gas compositions before and after the experiment were processed to unveil the gas exchange and estimate the actual oxygen influx across the membrane. A solely microbial activity driven oxygen influx of 10.7 mg O2/m[2]/h was observed. Measuring oxygen transfer from supply side provides a more straight-forward perspective on the role of active biofilm in membrane aerated biofilm reactor. The capability of the microbial activity to uptake oxygen on its own could potentially lead to greater energy savings in some MABR applications when strict aeration control is not needed.}, } @article {pmid33549582, year = {2021}, author = {Ranjith, K and Sharma, S and Shivaji, S}, title = {Microbes of the human eye: Microbiome, antimicrobial resistance and biofilm formation.}, journal = {Experimental eye research}, volume = {205}, number = {}, pages = {108476}, doi = {10.1016/j.exer.2021.108476}, pmid = {33549582}, issn = {1096-0007}, mesh = {*Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Drug Resistance, Bacterial ; Eye/*microbiology ; Eye Infections, Bacterial/microbiology ; Humans ; Microbiota/*physiology ; }, abstract = {BACKGROUND: The review focuses on the bacteria associated with the human eye using the dual approach of detecting cultivable bacteria and the total microbiome using next generation sequencing. The purpose of this review was to highlight the connection between antimicrobial resistance and biofilm formation in ocular bacteria.

METHODS: Pubmed was used as the source to catalogue culturable bacteria and ocular microbiomes associated with the normal eyes and those with ocular diseases, to ascertain the emergence of anti-microbial resistance with special reference to biofilm formation.

RESULTS: This review highlights the genetic strategies used by microorganisms to evade the lethal effects of anti-microbial agents by tracing the connections between candidate genes and biofilm formation.

CONCLUSION: The eye has its own microbiome which needs to be extensively studied under different physiological conditions; data on eye microbiomes of people from different ethnicities, geographical regions etc. are also needed to understand how these microbiomes affect ocular health.}, } @article {pmid33548326, year = {2021}, author = {Richert, A and Dąbrowska, GB}, title = {Enzymatic degradation and biofilm formation during biodegradation of polylactide and polycaprolactone polymers in various environments.}, journal = {International journal of biological macromolecules}, volume = {176}, number = {}, pages = {226-232}, doi = {10.1016/j.ijbiomac.2021.01.202}, pmid = {33548326}, issn = {1879-0003}, mesh = {Bacillus licheniformis/*physiology ; Bacterial Proteins/*metabolism ; Biodegradation, Environmental ; Biofilms/*growth & development ; Hydrolases/*metabolism ; Hypocreales/*physiology ; Polyesters/*metabolism ; }, abstract = {The present article presents the results of research on the susceptibility of polylactide, poly(ɛ-caprolactone) and mixtures to biodegradation in conditions imitating natural extracts of compost, activated sludge, sea and river water, determined by the biochemical oxygen consumption by microorganisms and susceptibility to enzymatic degradation with the use of enzyme solutions of fungal microbial origin. Analyzes of both types of degradation were carried out over a period of seven days and in four environments: compost, activated sludge, river and sea water, and four enzymatic solutions containing proteinase K, protease, esterase, and lipase. The amount of oxygen consumed by microorganisms in the presence of the tested films was determined, as well as the weight loss determined after the samples were incubated in enzymatic solutions. Images of the surface of individual samples, taken by fluorescence microscopy and scanning electron microscopy, confirm the formation of bacterial biofilm and the results of biochemical oxygen consumption by microorganisms, or weight loss. It was shown that the compost and activated sludge extract as well as the enzymes proteinase K from Engyodontium album (synonym Tritirachium album) and protease from Bacillus licheniformis had the greatest impact on the biodegradation of the tested materials.}, } @article {pmid33547340, year = {2021}, author = {Dawson, LF and Peltier, J and Hall, CL and Harrison, MA and Derakhshan, M and Shaw, HA and Fairweather, NF and Wren, BW}, title = {Extracellular DNA, cell surface proteins and c-di-GMP promote biofilm formation in Clostridioides difficile.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {3244}, pmid = {33547340}, issn = {2045-2322}, support = {MR/K000551/1/MRC_/Medical Research Council/United Kingdom ; 086418/Z/WT_/Wellcome Trust/United Kingdom ; MR/N013638/1/MRC_/Medical Research Council/United Kingdom ; G1000214/MRC_/Medical Research Council/United Kingdom ; 105609/Z/14/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Bacterial Proteins/*metabolism ; *Biofilms/growth & development ; Clostridioides difficile/*physiology/ultrastructure ; Clostridium Infections/microbiology ; Cyclic GMP/*analogs & derivatives/metabolism ; DNA, Bacterial/*metabolism ; Humans ; }, abstract = {Clostridioides difficile is the leading cause of nosocomial antibiotic-associated diarrhoea worldwide, yet there is little insight into intestinal tract colonisation and relapse. In many bacterial species, the secondary messenger cyclic-di-GMP mediates switching between planktonic phase, sessile growth and biofilm formation. We demonstrate that c-di-GMP promotes early biofilm formation in C. difficile and that four cell surface proteins contribute to biofilm formation, including two c-di-GMP regulated; CD2831 and CD3246, and two c-di-GMP-independent; CD3392 and CD0183. We demonstrate that C. difficile biofilms are composed of extracellular DNA (eDNA), cell surface and intracellular proteins, which form a protective matrix around C. difficile vegetative cells and spores, as shown by a protective effect against the antibiotic vancomycin. We demonstrate a positive correlation between biofilm biomass, sporulation frequency and eDNA abundance in all five C. difficile lineages. Strains 630 (RT012), CD305 (RT023) and M120 (RT078) contain significantly more eDNA in their biofilm matrix than strains R20291 (RT027) and M68 (RT017). DNase has a profound effect on biofilm integrity, resulting in complete disassembly of the biofilm matrix, inhibition of biofilm formation and reduced spore germination. The addition of exogenous DNase could be exploited in treatment of C. difficile infection and relapse, to improve antibiotic efficacy.}, } @article {pmid33547059, year = {2021}, author = {Kumar, M and Flint, S and Palmer, J and Chanapha, S and Hall, C}, title = {Influence of the incubation temperature and total dissolved solids concentration on the biofilm and spore formation of dairy isolates of Geobacillus stearothermophilus.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {8}, pages = {}, pmid = {33547059}, issn = {1098-5336}, abstract = {Geobacillus species are an important contaminant in the dairy industry and their presence is often considered as an indicator of poor plant hygiene with the potential to cause spoilage. They can form heat resistant spores that adhere to surfaces of processing equipment and germinate to form biofilms. Therefore, strategies aimed towards preventing or controlling biofilm formation in the dairy industry are desirable. In this study we demonstrate that the preferred temperature for biofilm and spore formation among Geobacillus stearothermophilus A1, D1, P3 and ATCC 12980 was 65°C. Increasing the total dissolved milk solids concentration to 20% (w/v) caused an apparent delay in the onset of biofilm and spore formation to detectable concentrations among all the strains at 55°C. Compared to the onset time of the biofilm formation of A1 in 10% (w/v) reconstituted skim milk, addition of milk protein (whey protein and sodium caseinate) caused an apparent delay in the onset of biofilm formation to detectable concentrations by an average of 10 h at 55°C. This study proposes that temperature and total dissolved solids concentration have a cumulative effect on the biofilm and spore formation of G. stearothermophilus A1, D1, P3 and ATCC 12980. In addition, the findings from this study may indicate that preconditioning of stainless-steel surface with adsorbed milk proteins may delay the onset of biofilm and spore formation of thermophilic bacteria during milk powder manufacture.IMPORTANCE The thermophilic bacilli, Geobacillus stearothermophilus is a predominant spoilage bacterium in milk powder manufacturing plants. If their numbers exceed the accepted levels, this may incur financial loses by lowering the price of the end product. Furthermore, they can form heat resistant spores which adhere to processing surfaces and can germinate to form biofilms. Previously conducted research had highlighted the variation in the spore and biofilm formation among three specific strains of G. stearothermophilus isolated from a milk powder manufacturing plant in New Zealand. The significance of our research is demonstrating the effect of two abiotic factors namely temperature and total dissolved solids concentration on the biofilm and spore formation of these three dairy isolates, leading to modifications in the thermal processing steps aimed towards controlling the biofilm and spore formation of G. stearothermophilus in the dairy industry.}, } @article {pmid33546487, year = {2021}, author = {Tran, TT and Hadinoto, K}, title = {A Potential Quorum-Sensing Inhibitor for Bronchiectasis Therapy: Quercetin-Chitosan Nanoparticle Complex Exhibiting Superior Inhibition of Biofilm Formation and Swimming Motility of Pseudomonas aeruginosa to the Native Quercetin.}, journal = {International journal of molecular sciences}, volume = {22}, number = {4}, pages = {}, pmid = {33546487}, issn = {1422-0067}, support = {LKCMedicine-SCBE CG-04/16//Nanyang Technological University/ ; }, mesh = {Anti-Bacterial Agents/administration & dosage/*chemistry/*pharmacology/therapeutic use ; Antineoplastic Agents/chemistry/pharmacology ; Biofilms/drug effects ; Bronchiectasis/drug therapy/etiology ; Chemical Phenomena ; Chitosan/chemistry ; Drug Carriers/chemistry ; Humans ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests ; Molecular Structure ; Nanoparticles/chemistry ; Particle Size ; Pseudomonas Infections/complications/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects ; Pulmonary Disease, Chronic Obstructive/complications ; Quercetin/chemistry ; Quorum Sensing/*drug effects ; Solubility ; Spectrum Analysis ; }, abstract = {Quercetin (QUE)-a plant-derived flavonoid, is recently established as an effective quorum sensing (QS) inhibiting agent in Pseudomonas aeruginosa-the main bacterial pathogen in bronchiectasis lungs. Successful clinical application of QUE, however, is hindered by its low solubility in physiological fluids. Herein we developed a solubility enhancement strategy of QUE in the form of a stable amorphous nanoparticle complex (nanoplex) of QUE and chitosan (CHI), which was prepared by electrostatically driven complexation between ionized QUE molecules and oppositely charged CHI. At its optimal preparation condition, the QUE-CHI nanoplex exhibited a size of roughly 150 nm with a 25% QUE payload and 60% complexation efficiency. The complexation with CHI had no adverse effect on the antibacterial and anticancer activities of QUE, signifying the preservation of QUE's bioactivities in the nanoplex. Compared to the native QUE, the QUE-CHI nanoplex exhibited superior QS inhibition in suppressing the QS-regulated swimming motility and biofilm formation of P. aeruginosa, but not in suppressing the virulence factor production. The superior inhibitions of the biofilm formation and swimming motility afforded by the nanoplex were attributed to (1) its higher kinetic solubility (5-times higher) that led to higher QUE exposures, and (2) the synergistic QS inhibition attributed to its CHI fraction.}, } @article {pmid33545912, year = {2021}, author = {Permana, AD and Anjani, QK and Sartini, and Utomo, E and Volpe-Zanutto, F and Paredes, AJ and Evary, YM and Mardikasari, SA and Pratama, MR and Tuany, IN and Donnelly, RF}, title = {Selective delivery of silver nanoparticles for improved treatment of biofilm skin infection using bacteria-responsive microparticles loaded into dissolving microneedles.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {120}, number = {}, pages = {111786}, doi = {10.1016/j.msec.2020.111786}, pmid = {33545912}, issn = {1873-0191}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Metal Nanoparticles ; Pseudomonas aeruginosa ; Rats ; Silver ; *Wound Infection ; }, abstract = {The treatment of infected chronic wounds has been hampered by development of bacterial biofilms and the low penetration of antibacterial compounds delivered by conventional dosage forms. Numerous bacterial biofilm formers have shown resistance to synthetic antibacterial agents. In this study, we explore the potential of silver nanoparticles (NPs) synthesized using green tea extract as antibiofilm agents against Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) biofilms. Due to the toxicity of silver NPs, for the first time, silver NPs were incorporated into bacteria-responsive microparticles (MPs) prepared from poly (Ɛ-caprolactone) decorated with chitosan. The in vitro release of silver NPs from MPs increased up to 9-times in the presence of SA and PA, showing the selectivity of this approach. Incorporation of the MPs into dissolving microneedles (DMNs) could enhance the dermatokinetic profiles of silver NPs compared to DMNs containing silver NPs without MP formulations and conventional cream formulations. Furthermore, 100% of bacterial bioburdens were eradicated on ex vivo biofilm model in rat skin following 60 h of the administration of this system. The findings revealed here confirmed the feasibility of the loading of silver NPs into responsive MPs for improved antibiofilm activities when delivered using DMNs. Following on from these promising results, toxicity and in vivo pharmacodynamic studies should now be carried out in an appropriate model.}, } @article {pmid33545416, year = {2021}, author = {Tong, H and Yu, X and Shi, Z and Liu, F and Yu, Y and Deng, F and He, J}, title = {Physicochemical properties, bond strength and dual-species biofilm inhibition effect of dental resin composites with branched silicone methacrylate.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {116}, number = {}, pages = {104368}, doi = {10.1016/j.jmbbm.2021.104368}, pmid = {33545416}, issn = {1878-0180}, mesh = {Animals ; Biofilms ; Composite Resins ; *Dental Bonding ; Dentin ; Dentin-Bonding Agents ; Materials Testing ; *Methacrylates ; Mice ; Resin Cements ; Silicones ; Surface Properties ; }, abstract = {Dental resin composites (DRCs) with 15 wt% (EC-15%) and 20 wt% (EC-20%) synthesized branched silicone methacrylate (BSM) in resin matrix have showed anti-adhesion effect against Streptococcus mutans. With the aim to evaluate the BSM containing DRCs further, water sorption (WS), solubility (SL), mechanical properties before and after water immersion, anti-adhesion effect against dual-species, bonding strength to adhesive treated dentin, and cytotoxicity of BSM containing DRCs were investigated. DRC without BSM was used as control. The WS and SL were obtained until the mass variation of composite in distilled water kept stable. Three-point bending test was used to evaluate flexural strength (FS) and modulus (FM) of composite before and after water immersion. Mixture of Streptococcus mutans and Lactobacillus acidophilus was used to study the anti-adhesion effect against dual-species. Bonding strength of composite to adhesive treated dentin was measured through macro-shear test. Extract of composite was used to evaluate its cytotoxicity effect on L-929 mouse fibroblasts, and cell viability was obtained by MTT assay. The results showed that EC-15% and EC-20% had similar WS and SL as control (p < 0.05); After water immersion, FS and FM of all composites decreased (p < 0.05), but there was no significant difference in value of FS and FM between different groups (p > 0.05); More bacteria were recovered from the surface of control than those from the surface of EC-15% and EC-20% (p < 0.05); Extract of EC-15% was less cytotoxic (higher cell viability) than those EC-20% and control (p < 0.05). All of results revealed that incorporation of 15 wt% or 20 wt% BSM in resin matrix could endow DRC with inhibition effect on dual-species biofilm formation without impairing physiochemical properties, bonding strength to adhesive treated dentin, and cytotoxicity of DRC.}, } @article {pmid33544817, year = {2021}, author = {Latorre, MC and Pérez-Granda, MJ and Savage, PB and Alonso, B and Martín-Rabadán, P and Samaniego, R and Bouza, E and Muñoz, P and Guembe, M}, title = {Endotracheal tubes coated with a broad-spectrum antibacterial ceragenin reduce bacterial biofilm in an in vitro bench top model.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {76}, number = {5}, pages = {1168-1173}, doi = {10.1093/jac/dkab019}, pmid = {33544817}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Humans ; Intubation, Intratracheal ; *Pneumonia, Ventilator-Associated/prevention & control ; Pseudomonas aeruginosa ; Steroids ; }, abstract = {BACKGROUND: Ventilator-associated pneumonia is one of the most common nosocomial infections, caused mainly by bacterial/fungal biofilm. Therefore, it is necessary to develop preventive strategies to avoid biofilm formation based on new compounds.

OBJECTIVES: We performed an in vitro study to compare the efficacy of endotracheal tubes (ETTs) coated with the ceragenin CSA-131 and that of uncoated ETTs against the biofilm of clinical strains of Pseudomonas aeruginosa (PA), Escherichia coli (EC) and Staphylococcus aureus (SA).

METHODS: We applied an in vitro bench top model using coated and uncoated ETTs that were treated with three different clinical strains of PA, EC and SA for 5 days. After exposure to biofilm, ETTs were analysed for cfu count by culture of sonicate and total number of cells by confocal laser scanning microscopy.

RESULTS: The median (IQR) cfu/mL counts of PA, EC and SA in coated and uncoated ETTs were, respectively, as follows: 1.00 × 101 (0.0-3.3 × 102) versus 3.32 × 109 (6.6 × 108-3.8 × 109), P < 0.001; 0.0 (0.0-5.4 × 103) versus 1.32 × 106 (2.3 × 103-5.0 × 107), P < 0.001; and 8.1 × 105 (8.5 × 101-1.4 × 109) versus 2.7 × 108 (8.6 × 106-1.6 × 1011), P = 0.058. The median (IQR) total number of cells of PA, EC and SA in coated and non-coated ETTs were, respectively, as follows: 11.0 [5.5-not applicable (NA)] versus 87.9 (60.5-NA), P = 0.05; 9.1 (6.7-NA) versus 62.6 (42.0-NA), P = 0.05; and 97.7 (94.6-NA) versus 187.3 (43.9-NA), P = 0.827.

CONCLUSIONS: We demonstrated significantly reduced biofilm formation in coated ETTs. However, the difference for SA was not statistically significant. Future clinical studies are needed to support our findings.}, } @article {pmid33544431, year = {2021}, author = {Jaiswal, P and Sharma, S and Pratap, A and Ansari, M and Shukla, VK and Basu, S and Banerjee, T}, title = {Significant presence of biofilm-producing gut-derived bacteria in anal fistula of chronic duration.}, journal = {International wound journal}, volume = {18}, number = {4}, pages = {519-524}, pmid = {33544431}, issn = {1742-481X}, mesh = {Bacteria ; Biofilms ; Humans ; *Rectal Fistula ; }, abstract = {Fistula-in-ano though not a life-threatening condition, yet its symptoms often significantly impact patients' social, intimate, and work lives. There is an established role of bacterial microflora in acute infections. However, we proposed that biofilm-forming organisms might be present in the microflora of anal fistula of prolonged duration. This aspect has rarely been studied earlier. Therefore, the study describes the microbiology of anal fistula and the biofilm-forming capacity of the isolated organisms. A total of 30 patients were included in the study as per the criteria. Anal fistula tissue sample, tissue fluid, and blood samples were collected from each individual. The collected specimens were detected for the presence of aerobic and anaerobic microflora through standard microbiological method and polymerase chain reaction. Furthermore, the role of biofilm formation by microtitre plate assay and serum matrix metalloproteinases-9 was also studied. The result showed significant predominance of gut-derived microflora with high-to-moderate biofilm-producing ability in anal fistulas of prolonged duration. The study emphasises the presence of biofilm-forming bacteria in chronic, non-healing fistula.}, } @article {pmid33541349, year = {2021}, author = {Tambone, E and Bonomi, E and Ghensi, P and Maniglio, D and Ceresa, C and Agostinacchio, F and Caciagli, P and Nollo, G and Piccoli, F and Caola, I and Fracchia, L and Tessarolo, F}, title = {Rhamnolipid coating reduces microbial biofilm formation on titanium implants: an in vitro study.}, journal = {BMC oral health}, volume = {21}, number = {1}, pages = {49}, pmid = {33541349}, issn = {1472-6831}, mesh = {Biofilms ; Coated Materials, Biocompatible ; *Dental Implants ; Glycolipids ; Staphylococcus aureus ; Surface Properties ; *Titanium ; }, abstract = {BACKGROUND: Peri-implant mucositis and peri-implantitis are biofilm-related diseases causing major concern in oral implantology, requiring complex anti-infective procedures or implant removal. Microbial biosurfactants emerged as new anti-biofilm agents for coating implantable devices preserving biocompatibility. This study aimed to assess the efficacy of rhamnolipid biosurfactant R89 (R89BS) to reduce Staphylococcus aureus and Staphylococcus epidermidis biofilm formation on titanium.

METHODS: R89BS was physically adsorbed on titanium discs (TDs). Cytotoxicity of coated TDs was evaluated on normal lung fibroblasts (MRC5) using a lactate dehydrogenase assay. The ability of coated TDs to inhibit biofilm formation was evaluated by quantifying biofilm biomass and cell metabolic activity, at different time-points, with respect to uncoated controls. A qualitative analysis of sessile bacteria was also performed by scanning electron microscopy.

RESULTS: R89BS-coated discs showed no cytotoxic effects. TDs coated with 4 mg/mL R89BS inhibited the biofilm biomass of S. aureus by 99%, 47% and 7% and of S. epidermidis by 54%, 29%, and 10% at 24, 48 and 72 h respectively. A significant reduction of the biofilm metabolic activity was also documented. The same coating applied on three commercial implant surfaces resulted in a biomass inhibition higher than 90% for S. aureus, and up to 78% for S. epidermidis at 24 h.

CONCLUSIONS: R89BS-coating was effective in reducing Staphylococcus biofilm formation at the titanium implant surface. The anti-biofilm action can be obtained on several different commercially available implant surfaces, independently of their surface morphology.}, } @article {pmid33540860, year = {2021}, author = {Pinheiro, ET and Karygianni, L and Attin, T and Thurnheer, T}, title = {Antibacterial Effect of High-Purity Nisin Alone and in Combination with D-Amino Acids or Chlorhexidine in an Endodontic-Like Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33540860}, issn = {2079-6382}, support = {2019/12908-3//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {New strategies to eradicate endodontic biofilms are needed. Therefore, we evaluated the effect of high-purity nisin alone and in combination with D-amino acids (D-AAs) or chlorhexidine (CHX) against an "endodontic-like" biofilm model. Biofilms were grown on hydroxyapatite discs for 64 h and treated with nisin, eight D-AAs mixture, nisin + eight D-AAs, 2% CHX, and nisin + 2% CHX. After the 5 min and 24 h treatments, biofilm cells were harvested and total colony-forming units were counted. Differences between groups were tested by two-way ANOVA followed by Tukey's multiple comparisons test (p < 0.05). Nisin and D-AAs, alone or in combination, were not effective in reducing bacteria after short or long exposure times. After 5 min, treatment with 2% CHX and nisin + 2% CHX resulted in 2 and 2.4-log cell reduction, respectively, compared with the no treatment control (p < 0.001). After 24 h, 2% CHX and nisin + 2% CHX drastically reduced bacterial counts. In conclusion, high-purity nisin alone or in combination with D-AAs did not show antibacterial activity against multispecies biofilms. Moreover, combined treatment using nisin and CHX showed similar antibiofilm activity compared with the use of CHX alone.}, } @article {pmid33540689, year = {2021}, author = {Cafiso, V and Lo Verde, F and Zega, A and Pigola, G and Rostagno, R and Borrè, S and Stefani, S}, title = {Genomic Characterization of a New Biofilm-Forming and Adhesive ST398 Human-Adapted MSSA Lineage Causing Septic Knee Arthritis Following Surgical Reconstruction.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33540689}, issn = {2076-2607}, support = {PRIN 2017SFBFER//MIUR Italy/ ; }, abstract = {Methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen commonly found in bone and joint infections, including septic arthritis. S. aureus virulence and the frailty of affected patients can cause several complications; a prompt and specific antibiotic treatment can positively affect the outcome of patients. We carried out an in-depth genomic characterization by Illumina whole genome sequencing and bioinformatics of two biofilm-producing M1 and M2 ST398 MSSA causing septic knee arthritis not-responding to antimicrobial therapy. The strains were characterized for antibiotic resistance, biofilm and adhesive properties as well as genomics, single nucleotide polymorphism phylogeny, resistomics and virulomics. Our results showed that M1 and M2 MSSA were ST398-t1451-agrI-Cap5, susceptible to cefoxitin and resistant to erythromycin and clindamycin, traits consistent with the lack of the SCCmec-locus and the presence of the sole blaZ and ermT. Furthermore, M1 and M2 were biofilm-producing and largely potentially adhesive strains, as indicated by the adhesion gene profile. Our data characterized a new human-adapted ST398 MSSA lineage, representing a "fusion" between the human-animal independent ST398 and the Livestock Associated (LA) ST398 lineages, forming biofilm and genomically predicted high adhesive, characterized by different genomic adaptation conferring a great ability to adhere to the host's extracellular matrix causing septic knee arthritis.}, } @article {pmid33540517, year = {2021}, author = {El-Khoury, N and Bennaceur, I and Verplaetse, E and Aymerich, S and Lereclus, D and Kallassy, M and Gohar, M}, title = {Massive Integration of Planktonic Cells within a Developing Biofilm.}, journal = {Microorganisms}, volume = {9}, number = {2}, pages = {}, pmid = {33540517}, issn = {2076-2607}, abstract = {During biofilm growth, the coexistence of planktonic and sessile cells can lead to dynamic exchanges between the two populations. We have monitored the fate of these populations in glass tube assays, where the Bacillus thuringiensis 407 strain produces a floating pellicle. Time-lapse spectrophotometric measurement methods revealed that the planktonic population grew until the pellicle started to be produced. Thereafter, the planktonic population decreased rapidly down to a value close to zero while the biofilm was in continuous growth, showing no dispersal until 120 h of culture. We found that this decrease was induced by the presence of the pellicle, but did not occur when oxygen availability was limited, suggesting that it was independent of cell death or cell sedimentation and that the entire planktonic population has integrated the biofilm. To follow the distribution of recruited planktonic cells within the pellicle, we tagged planktonic cells with GFP and sessile cells with mCherry. Fluorescence binocular microscopy observations revealed that planktonic cells, injected through a 24-h-aged pellicle, were found only in specific areas of the biofilm, where the density of sessile cells was low, showing that spatial heterogeneity can occur between recruited cells and sessile cells in a monospecies biofilm.}, } @article {pmid33539278, year = {2021}, author = {Mallick, S and Kiran, S and Maiti, TK and Ghosh, AS}, title = {PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {167}, number = {3}, pages = {}, doi = {10.1099/mic.0.001031}, pmid = {33539278}, issn = {1465-2080}, mesh = {Bacterial Adhesion ; *Biofilms ; Escherichia coli/genetics/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Penicillin-Binding Proteins/genetics/*metabolism ; Polysaccharides, Bacterial/*biosynthesis ; }, abstract = {Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.}, } @article {pmid33538938, year = {2021}, author = {Kaur, A and Soni, SK and Vij, S and Rishi, P}, title = {Cocktail of carbohydrases from Aspergillus niger: an economical and eco-friendly option for biofilm clearance from biopolymer surfaces.}, journal = {AMB Express}, volume = {11}, number = {1}, pages = {22}, pmid = {33538938}, issn = {2191-0855}, support = {F.No.7-261/2009/BSR//University Grants Commission (IN) (UGC-BSR)/ ; }, abstract = {Biofilm formation on both biotic and abiotic surfaces accounts for a major factor in spread of antimicrobial resistance. Due to their ubiquitous nature, biofilms are of great concern for environment as well as human health. In the present study, an integrated process for the co-production of a cocktail of carbohydrases from a natural variant of Aspergillus niger was designed. The enzyme cocktail was found to have a noteworthy potential to eradicate/disperse the biofilms of selected pathogens. For application of enzymes as an antibiofilm agent, the enzyme productivities were enhanced by statistical modelling using response surface methodology (RSM). The antibiofilm potential of the enzyme cocktail was studied in terms of (i) in vitro cell dispersal assay (ii) release of reducing sugars from the biofilm polysaccharides (iii) the effect of enzyme treatment on biofilm cells and architecture by confocal laser scanning microscopy (CLSM). Potential of the enzyme cocktail to disrupt/disperse the biofilm of selected pathogens from biopolymer surfaces was also assessed by field emission scanning electron microscopy (FESEM) analysis. Further, their usage in conjunction with antibiotics was assessed and it was inferred from the results that the use of enzyme cocktail augmented the efficacy of the antibiotics. The study thus provides promising insights into the prospect of using multiple carbohydrases for management of heterogeneous biofilms formed in natural and clinical settings.}, } @article {pmid33538114, year = {2021}, author = {Sun, F and Hung, HC and Yan, W and Wu, K and Shimchuk, AA and Gray, SD and He, W and Huang, X and Zhang, H}, title = {Inhibition of oral biofilm formation by zwitterionic nonfouling coating.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {109}, number = {10}, pages = {1418-1425}, doi = {10.1002/jbm.b.34801}, pmid = {33538114}, issn = {1552-4981}, mesh = {Bacterial Adhesion/drug effects ; Betaine/*chemistry ; Biofilms ; Catechols/*chemistry ; Coated Materials, Biocompatible/*chemistry ; Dental Caries/*prevention & control ; Dihydroxyphenylalanine/*chemistry ; Durapatite/chemistry ; Humans ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; Surface Properties ; }, abstract = {Inhibition of oral biofilm formation is critical to prevent and treat dental caries and periodontal diseases. In this study, we synthesized zwitterionic poly(carboxybetaine) (pCB) based polymer as a nonfouling coating to provide anti-bacterial properties to tooth surfaces. Four catechol derived l-3,4-dihydroxyphenylalanine (DOPA) groups were conjugated to pCB to serve as a surface anchoring group. The pCB-(DOPA)4 polymer was coated on the hydroxyapatite (HA) and enamel samples by simple immersion and characterized by Raman spectroscopy. The nonfouling effectiveness of the pCB based coating was determined by protein adsorption and bacterial adhesion assays. The coating was transparent on sample surfaces. The protein adsorption was significantly reduced to 8.2% and 6.9%, respectively, on pCB-(DOPA)4 coated HA and enamel samples. The pCB-(DOPA)4 -coated samples also demonstrated significantly fewer adhered Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus mutants compared to the control. This novel coating material provides an innovative approach to resist biofilm formation on tooth surfaces and has great potential in future dental clinical applications.}, } @article {pmid33538031, year = {2021}, author = {Duan, Y and Zhang, M and Shen, Z and Zhang, M and Zheng, B and Cheng, S and Hu, J}, title = {Photoresponsive Vesicles Enabling Sequential Release of Nitric Oxide (NO) and Gentamicin for Efficient Biofilm Eradication.}, journal = {Macromolecular rapid communications}, volume = {42}, number = {18}, pages = {e2000759}, doi = {10.1002/marc.202000759}, pmid = {33538031}, issn = {1521-3927}, support = {51690150//Natural Science Foundation of China/ ; 51690154//Natural Science Foundation of China/ ; 52073270//Natural Science Foundation of China/ ; 51722307//Natural Science Foundation of China/ ; 51973206//Natural Science Foundation of China/ ; WK3450000003//Fundamental Research Funds for the Central Universities/ ; WK2060190102//Fundamental Research Funds for the Central Universities/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Gentamicins/pharmacology ; Microbial Sensitivity Tests ; *Nitric Oxide ; Pseudomonas aeruginosa ; }, abstract = {The development of new antibacterial agents that can efficiently eradicate biofilms is of crucial importance to combat persistent and chronic bacterial infections. Herein, the fabrication of photoresponsive vesicles capable of the sequential release of nitric oxide (NO) and gentamicin sulfate (GS) is reported, which can not only efficiently disperse Pseudomonas aeruginosa (P. aeruginosa) PAO1 biofilm but also kill the planktonic bacteria. Well-defined amphiphilic diblockcopolymers of poly(ethylene oxide)-b-poly(4-((2-nitrobenzyl)(nitroso)amino)benzyl methacrylate) (PNO) is first synthesized through atom transfer radical polymerization (ATRP). The PNO diblock copolymer self-assembled into vesicles in aqueous solution, and a hydrophilic antibiotic of GS is subsequently encapsulated into the aqueous lumens of vesicles. The vesicles undergo visible light-mediated N-NO cleavage, releasing NO and disintegrating the vesicles with the release of the GS payload. The sequential release of NO and GS efficiently eradicate P. aeruginosa PAO1 biofilm and kill the liberated bacteria, showing a better antibiofilm effect than that of NO or GS alone.}, } @article {pmid33536503, year = {2021}, author = {Dotto, C and Lombarte Serrat, A and Ledesma, M and Vay, C and Ehling-Schulz, M and Sordelli, DO and Grunert, T and Buzzola, F}, title = {Salicylic acid stabilizes Staphylococcus aureus biofilm by impairing the agr quorum-sensing system.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {2953}, pmid = {33536503}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Quorum Sensing/drug effects ; Salicylic Acid/*pharmacology ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/drug effects/*pathogenicity ; Trans-Activators/genetics/metabolism ; Virulence Factors/genetics/metabolism ; }, abstract = {Salicylic acid (SAL) has recently been shown to induce biofilm formation in Staphylococcus aureus and to affect the expression of virulence factors. This study was aimed to investigate the effect of SAL on the regulatory agr system and its impact on S. aureus biofilm formation. The agr quorum-sensing system, which is a central regulator in S. aureus pathogenicity, plays a pivotal role in the dispersal of S. aureus mature biofilms and contributes to the creation of new colonization sites. Here, we demonstrate that SAL impairs biofilm dispersal by interfering with agr expression. As revealed by our work, protease and surfactant molecule production is diminished, and bacterial cell autolysis is also negatively affected by SAL. Furthermore, as a consequence of SAL treatment, the S. aureus biofilm matrix revealed the lack of extracellular DNA. In silico docking and simulation of molecular dynamics provided evidence for a potential interaction of AgrA and SAL, resulting in reduced activity of the agr system. In conclusion, SAL stabilized the mature S. aureus biofilms, which may prevent bacterial cell dissemination. However, it may foster the establishment of infections locally and consequently increase bacterial persistence leading to therapeutic failure.}, } @article {pmid33535577, year = {2021}, author = {Pica, M and Messere, N and Felicetti, T and Sabatini, S and Pietrella, D and Nocchetti, M}, title = {Biofunctionalization of Poly(lactide-co-glycolic acid) Using Potent NorA Efflux Pump Inhibitors Immobilized on Nanometric Alpha-Zirconium Phosphate to Reduce Biofilm Formation.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {3}, pages = {}, pmid = {33535577}, issn = {1996-1944}, support = {DELPHI projects through the program "Dipartimenti di Eccellenza 2018-2022"//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; Fondo per il sostegno della Ricerca di Base 2018//Università degli Studi di Perugia/ ; }, abstract = {Polymeric composites, where bioactive species are immobilized on inorganic nanostructured matrix, have received considerable attention as surfaces able to reduce bacterial adherence, colonization, and biofilm formation in implanted medical devices. In this work, potent in-house S. aureus NorA efflux pump inhibitors (EPIs), belonging to the 2-phenylquinoline class, were immobilized on nanometric alpha-zirconium phosphate (ZrP) taking into advantage of acid-base or intercalation reactions. The ZrP/EPI were used as filler of poly(lactide-co-glycolic acid) (PLGA) to obtain film composites with a homogeneous distribution of the ZrP/EPI fillers. As reference, PLGA films loaded with ZrP intercalated with thioridazine (TZ), that is recognized as both a NorA and biofilm inhibitor, and with the antibiotic ciprofloxacin (CPX) were prepared. Composite films were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The ability of the composite films, containing ZrP/EPI, to inhibit biofilm formation was tested on Staphylococcus aureus ATCC 29213 and Staphylococcus epidermidis ATCC 12228, and it was compared with that of the composite loaded with ZrP/TZ. Finally, the antibacterial activity of CPX intercalated in ZrP was evaluated when used in combination with ZrP/EPI in the PLGA films.}, } @article {pmid33532826, year = {2021}, author = {Tang, HJ and Lin, YT and Chen, CC and Chen, CW and Lu, YC and Ko, WC and Chen, HJ and Su, BA and Chang, PC and Chuang, YC and Lai, CC}, title = {Molecular characteristics and in vitro effects of antimicrobial combinations on planktonic and biofilm forms of Elizabethkingia anophelis.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {76}, number = {5}, pages = {1205-1214}, doi = {10.1093/jac/dkab018}, pmid = {33532826}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Flavobacteriaceae ; Microbial Sensitivity Tests ; *Plankton ; RNA, Ribosomal, 16S/genetics ; }, abstract = {OBJECTIVES: To investigate the in vitro activity of antibiotics against clinical Elizabethkingia anophelis isolates and to find a suitable antibiotic combination with synergistic effects to combat antibiotic-resistant E. anophelis and its associated biofilm.

METHODS: E. anophelis isolates were identified by 16S rRNA sequencing; 30 strains with different pulsotypes were identified and the MIC, antibiotic resistance mechanism, antibiotic combination activity and killing effects of antimicrobial agents on biofilms of these strains were determined.

RESULTS: All E. anophelis isolates were susceptible to minocycline and cefoperazone/sulbactam (1:1). More than 90% of clinical isolates were susceptible to cefoperazone/sulbactam (1:0.5), piperacillin/tazobactam and rifampicin. Some novel mutations, such as gyrA G81D, parE D585N and parC P134T, that have never been reported before, were identified. The synergistic effect was most prominent for the combination of minocycline and rifampicin, with 93.3% of their FIC index values ≤0.5, and no antagonism was observed using the chequerboard method. This synergistic effect between minocycline and rifampicin was also observed using time-killing methods for clinical E. anophelis isolates at both normal inoculum and high inoculum. Twenty-nine isolates tested positive for biofilm formation. Minocycline remained active against biofilm-embedded and biofilm-released planktonic E. anophelis cells; however, the enhanced effect of minocycline by adding rifampicin was only observed at 24 h (not at 72 and 120 h).

CONCLUSIONS: Although E. anophelis was resistant to many antibiotics and could exhibit biofilm formation, minocycline showed potent in vitro activity against this pathogen and its associated biofilm.}, } @article {pmid33532361, year = {2021}, author = {Anggani, HS and Perdana, RG and Siregar, E and Bachtiar, EW}, title = {The effect of coating chitosan on Porphyromonas gingivalis biofilm formation in the surface of orthodontic mini-implant.}, journal = {Journal of advanced pharmaceutical technology & research}, volume = {12}, number = {1}, pages = {84-88}, pmid = {33532361}, issn = {2231-4040}, abstract = {Infection is the main problem for the failure of orthodontic mini-implant. Modern prevention of infection is now focused on local antibacterial coatings on implant devices. Chitosan is biocompatible and has antibacterial properties. Azithromycin is a synthetic antibiotic with immunomodulatory properties in which it has an advantage over the rest of antibiotics. This study aimed to evaluate the effect coating chitosan on the orthodontic mini-implant in Porphyromonas gingivalis biofilm formation. This is an experimental study using 25 orthodontic mini-implants. Five samples were coated with chitosan, 5 samples were coated with chitosan-azithromycin, 5 samples were coated with azithromycin, 5 samples were uncoated, and 5 samples were uncoated and were not exposed to P. gingivalis. P. gingivalis biofilms on the surface of the orthodontic mini-implant were observed after 24 h of incubation. P. gingivalis biofilm mass inhibition was highest in the azithromycin-treated group, followed by chitosan + azithromycin and chitosan only. The one-way ANOVA statistic test and post hoc Bonferroni statistic test of P. gingivalis biofilm mass show a significant difference between and within groups of experiments (P < 0.05). The Pearson correlation test with a value of R = +0.88, indicated that the bacterial viability count and the biofilm mass have a strong positive correlation. In conclusion, orthodontic mini-implant coated with chitosan, chitosan with azithromycin, or azithromycin only effectively suppressed P. gingivalis biofilm formation.}, } @article {pmid33531388, year = {2021}, author = {Katharios-Lanwermeyer, S and Whitfield, GB and Howell, PL and O'Toole, GA}, title = {Pseudomonas aeruginosa Uses c-di-GMP Phosphodiesterases RmcA and MorA To Regulate Biofilm Maintenance.}, journal = {mBio}, volume = {12}, number = {1}, pages = {}, pmid = {33531388}, issn = {2150-7511}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; MOP 43998//CIHR/Canada ; FDN154327//CIHR/Canada ; }, mesh = {*Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Phosphoric Diester Hydrolases/*physiology ; Pseudomonas aeruginosa/*physiology ; Signal Transduction/physiology ; }, abstract = {While the early stages of biofilm formation have been well characterized, less is known about the requirements for Pseudomonas aeruginosa to maintain a mature biofilm. We utilized a P. aeruginosa-phage interaction to identify rmcA and morA, two genes which encode bis-(3',5')-cyclic dimeric GMP (c-di-GMP)-degrading phosphodiesterases (PDEs) and are important for the regulation of biofilm maintenance. Deletion of these genes initially results in an elevated biofilm phenotype characterized by increased production of c-di-GMP, Pel polysaccharide, and/or biofilm biomass. In contrast to the wild-type strain, these mutants were unable to maintain the biofilm when exposed to carbon-limited conditions. The susceptibility to nutrient limitation, as well as subsequent loss of biofilm viability of these mutants, was phenotypically reproduced with a stringent response mutant (ΔrelA ΔspoT), indicating that the ΔrmcA and ΔmorA mutants may be unable to appropriately respond to nutrient limitation. Genetic and biochemical data indicate that RmcA and MorA physically interact with the Pel biosynthesis machinery, supporting a model whereby unregulated Pel biosynthesis contributes to the death of the ΔrmcA and ΔmorA mutant strains in an established biofilm under nutrient limitation. These findings provide evidence that c-di-GMP-mediated regulation is required for mature biofilms of P. aeruginosa to effectively respond to changing availability of nutrients. Furthermore, the PDEs involved in biofilm maintenance are distinct from those required for establishing a biofilm, suggesting that a wide variety of c-di-GMP metabolizing enzymes in organisms such as P. aeruginosa allows for discrete control over the formation, maintenance or dispersion of biofilms.IMPORTANCE Recent advances in our understanding of c-di-GMP signaling have provided key insights into the regulation of biofilms. Despite an improved understanding of how biofilms initially form, the processes that facilitate the long-term maintenance of these multicellular communities remain opaque. We found that P. aeruginosa requires two phosphodiesterases, RmcA and MorA, to maintain a mature biofilm and that biofilms lacking these PDEs succumb to nutrient limitation and die. The biofilm maintenance deficiency observed in ΔrmcA and ΔmorA mutants was also found in the stringent response-defective ΔrelA ΔspoT strain, suggesting that a regulatory intersection between c-di-GMP signaling, extracellular polysaccharide biosynthesis, and the nutrient limitation response is important for biofilm persistence. We uncover components of an important regulatory system needed for P. aeruginosa biofilms to persist in nutrient-poor conditions and provide some of the first evidence that maintaining a mature biofilm is an active process.}, } @article {pmid33531042, year = {2021}, author = {Ugwuanyi, FC and Ajayi, A and Ojo, DA and Adeleye, AI and Smith, SI}, title = {Evaluation of efflux pump activity and biofilm formation in multidrug resistant clinical isolates of Pseudomonas aeruginosa isolated from a Federal Medical Center in Nigeria.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {20}, number = {1}, pages = {11}, pmid = {33531042}, issn = {1476-0711}, mesh = {Bacterial Outer Membrane Proteins ; *Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Membrane Transport Proteins ; Phenotype ; Pseudomonas aeruginosa/*drug effects/genetics/metabolism ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa an opportunistic pathogen, is widely associated with nosocomial infections and exhibits resistance to multiple classes of antibiotics. The aim of this study was to determine the antibiotic resistance profile, biofilm formation and efflux pump activity of Pseudomonas strains isolated from clinical samples in Abeokuta Ogun state Nigeria.

METHODS: Fifty suspected Pseudomonas isolates were characterized by standard biochemical tests and PCR using Pseudomonas species -specific primers. Antibiotic susceptibility testing was done by the disc diffusion method. Efflux pump activity screening was done by the ethidium bromide method and biofilm formation assay by the tissue plate method. Genes encoding biofilm formation (pslA & plsD) and efflux pump activity (mexA, mexB and oprM) were assayed by PCR.

RESULTS: Thirty-nine Pseudomonas spp. were identified of which 35 were Pseudomonas aeruginosa and 4 Pseudomonas spp. All 39 (100%) Pseudomonas isolates were resistant to ceftazidime, cefuroxime and amoxicillin-clavulanate. Thirty-six (92%), 10(25.6%), 20 (51.2%), 11(28%) and 9(23%) of the isolates were resistant to nitrofurantoin, imipenem, gentamicin, cefepime and aztreonam respectively. All the isolates had the ability to form biofilm and 11 (28%) of them were strong biofilm formers. They all (100%) harboured the pslA and pslD biofilm encoding genes. Varied relationships between biofilm formation and resistance to ciprofloxacin, ofloxacin, cefixime, gentamicin, imipenem, and aztreonam were observed. Only 23(59%) of the Pseudomonas isolates phenotypically exhibited efflux pump activity but mexA gene was detected in all 39 (100%) isolates while mexB and oprM genes were detected in 91%, 92%, and 88% of strong, moderate and weak biofilm formers respectively.

CONCLUSION: Multidrug resistance, biofilm and efflux pump capabilities in Pseudomonas aeruginosa have serious public health implications in the management of infections caused by this organism.}, } @article {pmid33530836, year = {2021}, author = {Wang, S and Long, L and Yang, X and Qiu, Y and Tao, T and Peng, X and Li, Y and Han, A and Senadheera, DB and Downey, JS and Goodman, SD and Zhou, X and Cvitkovitch, DG}, title = {Dissecting the Role of VicK Phosphatase in Aggregation and Biofilm Formation of Streptococcus mutans.}, journal = {Journal of dental research}, volume = {100}, number = {6}, pages = {631-638}, pmid = {33530836}, issn = {1544-0591}, support = {R01 DE013965/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; *Phosphoric Monoester Hydrolases ; *Streptococcus mutans ; Virulence ; }, abstract = {VicRK (WalRK or YycFG) is a conserved 2-component regulatory system (TCS) that regulates cell division, cell wall biosynthesis, and homeostasis in low-GC Gram-positive bacteria. VicRK is also associated with biofilm formation of Streptococcus mutans on the tooth surface as it directly regulates the extracellular polysaccharide (EPS) synthesis. Of the 2 components, VicK possesses both autokinase and phosphatase activities, which regulate the phosphorylation and dephosphorylation of the regulator VicR in response to environmental cues. However, the dual mechanism of VicK as the autokinase/phosphatase in regulating S. mutans' responses is not well elucidated. Previously, it has been shown that the phosphatase activity depends on the PAS domain and residues in the DHp domain of VicK in S. mutans. Specifically, mutating proline at 222 in the PAS domain inhibits VicK phosphatase activity. We generated a VicK[P222A] mutant to determine the level of VicR-P in the cytoplasm by Phos-tag sodium dodecyl sulfate polyacrylamide gel electrophoresis. We show that in VicK[P222A] phosphatase, attenuation increased phosphorylated VicR (VicR-P) that downregulated glucosyltransferases, gtfBC, thereby reducing the synthesis of water-insoluble polysaccharides (WIS-EPS) in the biofilm. In addition, VicK[P222A] presented as long-rod cells, reduced growth, and displayed asymmetrical division. A major adhesin of S. mutans, SpaP was downregulated in VicK[P222A], making it unable to agglutinate in saliva. In summary, we have confirmed that VicK phosphatase activity is critical to maintain optimal phosphorylation status of VicR in S. mutans, which is important for cell growth, cell division, EPS synthesis, and bacterial agglutination in saliva. Hence, VicK phosphatase activity may represent a promising target to modulate S. mutans' pathogenicity.}, } @article {pmid33530340, year = {2021}, author = {Schnurr, E and Paqué, PN and Attin, T and Nanni, P and Grossmann, J and Holtfreter, S and Bröker, BM and Kohler, C and Diep, BA and Ribeiro, AA and Thurnheer, T}, title = {Staphylococcus aureus Interferes with Streptococci Spatial Distribution and with Protein Expression of Species within a Polymicrobial Oral Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33530340}, issn = {2079-6382}, support = {E-26/ 203.512/2015//FAPERJ (Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro)/ ; }, abstract = {We asked whether transient Staphylococcus aureus in the oral environment synergistically interacts with orally associated bacterial species such as Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus mutans, and Veillonella dispar (six-species control biofilm 6S). For this purpose, four modified biofilms with seven species that contain either the wild type strain of the S. aureus genotype (USA300-MRSA WT), its isogenic mutant with MSCRAMM deficiency (USA300-MRSA ΔMSCRAMM), a methicillin-sensitive S. aureus (ST72-MSSA-) or a methicillin-resistant S. aureus (USA800-MRSA) grown on hydroxyapatite disks were examined. Culture analyses, confocal-laser-scanning microscopy and proteome analyses were performed. S. aureus strains affected the amount of supragingival biofilm-associated species differently. The deletion of MSCRAMM genes disrupted the growth of S. aureus and the distribution of S. mutans and S. oralis within the biofilms. In addition, S. aureus caused shifts in the number of detectable proteins of other species in the 6S biofilm. S. aureus (USA300-MRSA WT), aggregated together with early colonizers such as Actinomyces and streptococci, influenced the number of secondary colonizers such as Fusobacterium nucleatum and was involved in structuring the biofilm architecture that triggered the change from a homeostatic biofilm to a dysbiotic biofilm to the development of oral diseases.}, } @article {pmid33529773, year = {2021}, author = {Kia, C and Cusano, A and Messina, J and Muench, LN and Chadayammuri, V and McCarthy, MB and Umejiego, E and Mazzocca, AD}, title = {Effectiveness of topical adjuvants in reducing biofilm formation on orthopedic implants: an in vitro analysis.}, journal = {Journal of shoulder and elbow surgery}, volume = {30}, number = {9}, pages = {2177-2183}, doi = {10.1016/j.jse.2020.12.009}, pmid = {33529773}, issn = {1532-6500}, mesh = {Animals ; Biofilms ; Prostheses and Implants ; *Prosthesis-Related Infections/prevention & control ; Sheep ; Staphylococcus aureus ; Staphylococcus epidermidis ; }, abstract = {BACKGROUND AND HYPOTHESIS: The treatment of periprosthetic joint infection is complicated by the presence of residual biofilm, which resists eradication owing to bacterial adherence to orthopedic implants. The purpose of this study was to compare Bactisure (Zimmer Biomet, Warsaw, IN, USA), povidone-iodine (Betadine), and chlorhexidine gluconate solution (Irrisept; Irrimax, Gainesville, FL, USA) in reducing biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes inoculated on cobalt-chrome, titanium, and stainless steel disks, representing metals commonly used for shoulder arthroplasty. The hypothesis was that there would be no significant difference in biofilm reduction among the 3 topical adjuvants.

METHODS: Strains of S aureus (ATCC 35556), S epidermidis (ATCC 35984), and C acnes (LMG 16711) were grown on cobalt-chrome, titanium, and stainless steel disks. For each strain, the disks were divided into 4 groups: (1) control, (2) povidone-iodine (Betadine), (3) chlorhexidine gluconate (Irrisept), and (4) Bactisure. Bacteria were grown on 5% sheep blood agar plates. Biofilm eradication was quantified using adenosine triphosphate bioluminescence and compared with controls 48 and 72 hours after implementation of the topical adjuvant.

RESULTS: At 72 hours after implementation of the topical adjuvant, a statistically significant reduction in colony-forming units was observed for all topical adjuvants across all tested metals, as compared with their respective control. With respect to the topical adjuvants themselves, Bactisure more consistently demonstrated the most significant reduction in colony-forming units across all bacteria when the tested medium was adjusted for, with the exception of S aureus, which showed similar results to Betadine at 72 hours.

CONCLUSION: By use of commonly encountered topical adjuvants on S aureus-, S epidermidis-, and C acnes-inoculated disks of various implant metals, a significant reduction in biofilm production was observed. Bactisure, a recent Food and Drug Administration-approved topical adjuvant, demonstrated the overall greatest efficacy of the agents studied.}, } @article {pmid33528277, year = {2021}, author = {Suryaletha, K and Chandrika, SK and Thomas, S}, title = {Comprehensive genomics depict accessory genes encoding pathogenicity and biofilm determinants in Enterococcus faecalis.}, journal = {Future microbiology}, volume = {16}, number = {3}, pages = {175-184}, doi = {10.2217/fmb-2020-0111}, pmid = {33528277}, issn = {1746-0921}, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; CRISPR-Cas Systems ; Enterococcus faecalis/*genetics/*pathogenicity/physiology ; Genome, Bacterial ; Genomic Islands ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Plasmids/genetics/metabolism ; Virulence ; }, abstract = {Aim:Enterococcus faecalis is a leading nosocomial pathogen in biofilm-associated polymicrobial infections. The study aims to understand pathogenicity and biofilm determinants of the pathogen by genome analysis. Methodology: Genome sequencing of a strong biofilm forming clinical isolate Enterococcus faecalis SK460 devoid of Fsr quorum-signaling system, was performed and comparative genomics was carried out among a set of pathogenic biofilm formers and nonpathogenic weak biofilm formers. Results: Analysis revealed a pool of virulence and adhesion related factors associated with pathogenicity. Absence of CRISPR-Cas system facilitated acquisition of pheromone responsive plasmid, pathogenicity island and phages. Comprehensive analysis identified a subset of accessory genes encoding polysaccharide lyase, sugar phosphotransferase system, phage proteins and transcriptional regulators exclusively in pathogenic biofilm formers. Conclusion: The study identified a set of genes specific to pathogenic biofilm formers and these can act as targets which in turn help to develop future treatment endeavors against enterococcal infections.}, } @article {pmid33526771, year = {2021}, author = {Cantillon, D and Wroblewska, J and Cooper, I and Newport, MJ and Waddell, SJ}, title = {Three-dimensional low shear culture of Mycobacterium bovis BCG induces biofilm formation and antimicrobial drug tolerance.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {12}, pmid = {33526771}, issn = {2055-5008}, mesh = {Antitubercular Agents/*pharmacology ; Bacterial Proteins/genetics ; Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Culture Media/chemistry ; Drug Resistance, Bacterial ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Isoniazid/pharmacology ; Mycobacterium bovis/genetics/*physiology ; Phenotype ; Rifampin/pharmacology ; Sigma Factor/genetics ; Streptomycin/pharmacology ; Virulence Factors/genetics ; }, abstract = {Mycobacteria naturally grow as corded biofilms in liquid media without detergent. Such detergent-free biofilm phenotypes may reflect the growth pattern of bacilli in tuberculous lung lesions. New strategies are required to treat tuberculosis, which is responsible for more deaths each year than any other bacterial disease. The lengthy 6-month regimen for drug-sensitive tuberculosis is necessary to remove antimicrobial drug tolerant populations of bacilli that persist through drug therapy. The role of biofilm-like growth in the generation of these sub-populations remains poorly understood despite the hypothesised clinical significance and mounting evidence of biofilms in pathogenesis. We adapt a three-dimensional Rotary Cell Culture System to model M. bovis BCG biofilm growth in low-shear detergent-free liquid suspension. Importantly, biofilms form without attachment to artificial surfaces and without severe nutrient starvation or environmental stress. Biofilm-derived planktonic bacilli are tolerant to isoniazid and streptomycin, but not rifampicin. This phenotypic drug tolerance is lost after passage in drug-free media. Transcriptional profiling reveals induction of cell surface regulators, sigE and BCG_0559c alongside the ESX-5 secretion apparatus in these low-shear liquid-suspension biofilms. This study engineers and characterises mycobacteria grown as a suspended biofilm, illuminating new drug discovery pathways for this deadly disease.}, } @article {pmid33526753, year = {2021}, author = {Damrongsaktrakul, P and Ruengvisesh, S and Rahothan, A and Sukhumrat, N and Tuitemwong, P and Phung-On, I}, title = {Removal of Salmonella Typhimurium Biofilm from Food Contact Surfaces Using Quercus infectoria Gall Extract in Combination with a Surfactant.}, journal = {Journal of microbiology and biotechnology}, volume = {31}, number = {3}, pages = {439-446}, pmid = {33526753}, issn = {1738-8872}, mesh = {Biofilms/*drug effects ; Cetrimonium/*pharmacology ; Colony Count, Microbial ; Decontamination/methods ; Food Microbiology ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plant Tumors ; Polypropylenes ; Quercus/chemistry ; Salmonella typhimurium/*drug effects ; Sodium Dodecyl Sulfate/*pharmacology ; Stainless Steel ; Surface-Active Agents/pharmacology ; }, abstract = {Quercus infectoria (nutgall) has been reported to possess antimicrobial activities against a wide range of pathogens. Nevertheless, the biofilm removal effect of nutgall extract has not been widely investigated. In this study, we therefore evaluated the effect of nutgall extract in combination with cetrimonium bromide (CTAB) against preformed biofilm of Salmonella Typhimurium on polypropylene (PP) and stainless steel (SS) coupons in comparison with other sanitizers. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of nutgall extract and surfactants (CTAB and sodium dodecyl sulfate; SDS) were assessed. CTAB showed a more efficient antimicrobial activity than SDS and was selected to use in combination with nutgall extract for removing biofilm. To determine the biofilm removal efficacy, the PP and SS coupons were individually submerged in 2x MBC of nutgall extract (256 mg/ml) + 2x MBC of CTAB (2.5 mg/ml), nutgall extract alone (256 mg/ml), CTAB alone (2.5 mg/ml), distilled water, and 100 ppm sodium hypochlorite for 5, 15, and 30 min. The remaining sessile cells in biofilm were determined. Overall, the greatest biofilm removal efficacy was observed with nutgall extract + CTAB; the biofilm removal efficacy of sanitizers tended to increase with the exposure time. The SEM analysis demonstrated that S. Typhimurium biofilm on PP and SS coupons after exposure to nutgall extract + CTAB for 30 min displayed morphological alterations with wrinkles. This study suggests nutgall extract + CTAB may be an alternative to commonly used sanitizers to remove biofilm from food contact surfaces in the food industry and household.}, } @article {pmid33526439, year = {2021}, author = {Zhang, YX and Zhang, ML and Wang, XW}, title = {C-Type Lectin Maintains the Homeostasis of Intestinal Microbiota and Mediates Biofilm Formation by Intestinal Bacteria in Shrimp.}, journal = {Journal of immunology (Baltimore, Md. : 1950)}, volume = {206}, number = {6}, pages = {1140-1150}, doi = {10.4049/jimmunol.2000116}, pmid = {33526439}, issn = {1550-6606}, mesh = {Animals ; Arthropod Proteins/genetics/*metabolism ; Bacteria/*immunology ; Biofilms ; Dysbiosis/genetics/immunology/microbiology ; Gastrointestinal Microbiome/*immunology ; Gene Knockdown Techniques ; Homeostasis/immunology ; Host Microbial Interactions/immunology ; Lectins, C-Type/genetics/*metabolism ; Penaeidae/*immunology/metabolism/microbiology ; Protein Domains ; }, abstract = {Intestinal microbiota are closely related to host physiology. Over the long course of evolution and interaction, both commensal bacteria and their host have evolved multiple strategies to adapt to each other. However, in invertebrates, the regulatory mechanism of intestinal microbiota homeostasis is largely unknown. In the current study, a digestive tract-specific C-type lectin, designated as CTL33, was identified because of its abundance and response to bacteria in the intestine of kuruma shrimp (Marsupenaeus japonicus). Silencing of CTL33 expression led directly to intestinal dysbiosis, tissue damage, and shrimp death. CTL33 could facilitate biofilm formation by the intestinal bacteria. This function originated from its unique architecture, with a lectin domain responsible for bacteria recognition and a coiled coil region that mediated CTL33 dimerization and cross-linked the bacteria into a biofilm-like complex. By mediating the formation of a biofilm, CTL33 promoted the establishment of intestinal bacteria in intestine and maintained the homeostasis of the microbiota. Thus, to our knowledge, we demonstrated a new mechanism of C-type lectin-mediated biofilm formation by intestinal bacteria, providing new insights into intestinal homeostasis regulation in invertebrates.}, } @article {pmid33525975, year = {2021}, author = {Dai, K and Yang, Z and Ma, X and Chang, YF and Cao, S and Zhao, Q and Huang, X and Wu, R and Huang, Y and Xia, J and Yan, Q and Han, X and Ma, X and Wen, X and Wen, Y}, title = {Deletion of Polyamine Transport Protein PotD Exacerbates Virulence in Glaesserella (Haemophilus) parasuis in the Form of Non-biofilm-generated Bacteria in a Murine Acute Infection Model.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {520-546}, pmid = {33525975}, issn = {2150-5608}, mesh = {Animals ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Disease Models, Animal ; Female ; Gene Deletion ; Haemophilus Infections/microbiology ; Haemophilus parasuis/*genetics/*pathogenicity ; Membrane Transport Proteins/*genetics/metabolism ; Mice ; Polyamines/*metabolism ; Specific Pathogen-Free Organisms ; Virulence/genetics ; }, abstract = {Polyamines are small, polycationic molecules with a hydrocarbon backbone and multiple amino groups required for optimal cell growth. The potD gene, belonging to the ABC (ATP-binding cassette) transport system potABCD, encodes the bacterial substrate-binding subunit of the polyamine transport system, playing a pivotal role in bacterial metabolism and growth. The swine pathogen Glaesserella parasuis possesses an intact pot operon, and the studies presented here mainly examined the involvement of PotD in Glaesserella pathogenesis. A potD-deficient mutant was constructed using a virulent G. parasuis strain SC1401 by natural transformation; immuno-electron microscopy was used to identify the subcellular location of native PotD protein; an electron microscope was adopted to inspect biofilm and bacterial morphology; immunofluorescence technique was employed to study cellular adhesion, the levels of inflammation and apoptosis. The TSA++-pre-cultured mutant strain showed a significantly reduced adhesion capacity to PK-15 and MLE-12 cells. Likewise, we also found attenuation in virulence using murine models focusing on the clinical sign, H&E, and IFA for inflammation and apoptosis. However, when the mutant was grown in TSB++, virulence recovered to normal levels, along with a high level of radical oxygen species formation in the host. The expression of PotD could actively stimulate the production of ROS in Raw 264.7. Our data suggested that PotD from G. parasuis has a high binding potential to polyamine, and is essential for the full bacterial virulence within mouse models. However, the virulence of the potD mutant is highly dependent on its TSA++ culture conditions rather than on biofilm-formation.}, } @article {pmid33524754, year = {2021}, author = {Zeng, XC and Xu, Y and He, Z and Wang, Y and Chen, X}, title = {A powerful arsenite-oxidizing biofilm bioreactor derived from a single chemoautotrophic bacterial strain: Bioreactor construction, long-term operations and kinetic analysis.}, journal = {Chemosphere}, volume = {273}, number = {}, pages = {129672}, doi = {10.1016/j.chemosphere.2021.129672}, pmid = {33524754}, issn = {1879-1298}, mesh = {*Arsenic ; *Arsenites ; Biofilms ; Bioreactors ; Kinetics ; Oxidation-Reduction ; }, abstract = {Microbial oxidation of As(III) by biofilm bioreactors followed by adsorption is a promising and environment friendly approach to remediate As(III) contaminated groundwater; however, poor activity, stability and expandability of the bioreactors hampered their industrious applications. To resolve this issue, we constructed a new biofilm bioreactor using a powerful chemoautotrophic As(III)-oxidizing bacterium Rhizobium sp. A219. This strain has strong ability to form biofilms and possesses very high As(III)-oxidizing activities in both planktonic and biofilm forms. Perlites were used as the biofilm carriers. Long-term operations suggest that the bioreactor has very high efficiency, stability and scalability under different geochemical conditions, and it is cheap and easy to construct and operate. During the operations, it is only required to supply air, nothing else. All the common contaminants in groundwater slightly affected the bioreactor As(III)-oxidizing activity. The common contaminants in groundwater can be largely removed through assimilation by the bacterial cells as nutrition. The bioreactor completely oxidize 1.0, 5.0, 10.0, 20.0 and 30.0 mg/L As(III) in 12, 18, 20, 25 and 30 min, respectively. Approximately 18, 18, 12, 12 and 21 min were needed to oxidize 1.1 mg/L As(III) at 20, 25, 30, 35 and 40 °C, respectively. The bioreactor works well under the pH values of 5-8, and the most optimal was 7.0. The data suggest that this bioreactor possesses the highest efficiency and stability, and thus has the great potential for industrial applications among all the described As(III)-oxidizing bioreactors derived from a single bacterium.}, } @article {pmid33523627, year = {2021}, author = {Zhang, Y and Wayner, CC and Wu, S and Liu, X and Ball, WP and Preheim, SP}, title = {Effect of Strain-Specific Biofilm Properties on the Retention of Colloids in Saturated Porous Media under Conditions of Stormwater Biofiltration.}, journal = {Environmental science & technology}, volume = {55}, number = {4}, pages = {2585-2596}, doi = {10.1021/acs.est.0c06177}, pmid = {33523627}, issn = {1520-5851}, mesh = {*Biofilms ; *Colloids ; Filtration ; Porosity ; Surface Properties ; }, abstract = {Filter performance can be affected by bacterial colonization of the filtration media, yet little is known about how naturally occurring bacteria modify the surface properties of filtration media to affect colloidal removal. We used sand columns and simulated stormwater conditions to study the retention of model colloidal particles, carboxyl-modified-latex (CML) beads, in porous media colonized by naturally occurring bacterial strains. Colloid retention varied substantially across identical columns colonized by different, in some cases closely related, bacterial strains in a cell density independent manner. Atomic force microscopy was applied to quantify the interaction energy between CML beads and each bacterial strain's biofilm surface. We found interaction energy between CML and each strain was significantly different, with adhesive energies between the biofilm and CML, presumed to be associated with polymer-surface bonding, a better predictor of CML retention than other strain characteristics. Overall, the findings suggest that interactions with biopolymers in naturally occurring bacterial biofilms strongly influence colloid retention in porous media. This work highlights the need for more investigation into the role of biofilm microbial community composition on colloid removal in porous media to improve biofilter design and operation.}, } @article {pmid33522301, year = {2021}, author = {Khelissa, S and Gharsallaoui, A and Wang, J and Dumas, E and Barras, A and Jama, C and Jbilou, F and Loukili, N and Chihib, NE}, title = {Anti-biofilm activity of dodecyltrimethylammonium chloride microcapsules against Salmonella enterica serovar Enteritidis and Staphylococcus aureus.}, journal = {Biofouling}, volume = {37}, number = {1}, pages = {49-60}, doi = {10.1080/08927014.2021.1873958}, pmid = {33522301}, issn = {1029-2454}, mesh = {Biofilms ; Capsules ; Quaternary Ammonium Compounds ; *Salmonella enteritidis ; *Staphylococcus aureus ; }, abstract = {Dodecyltrimethylammonium chloride (DTAC) was trapped into maltodextrins/pectin spray dried microcapsules to improve its activity against Salmonella enteritidis and Staphylococcus aureus biofilms. Two different microcapsules were prepared: uncomplexed DTAC-microcapsules (UDM), containing DTAC and maltodextrins; and complexed DTAC-microcapsules (CDM) containing DTAC complexed with pectin and maltodextrins. The minimum inhibitory concentrations (MIC) of both free and microencapsulated DTAC were investigated against S. Enteritidis and S. aureus. The MICs of DTAC were significantly lower when encapsulated. CDM treatment resulted in a 2 and 3.2 log reduction in S. aureus and S. Enteritidis biofilm culturable biomass, respectively. Microencapsulation reduced the cytotoxicity of DTAC by up to 32-fold. Free DTAC and CDM targeted the cell membrane resulting in the leakage of the intracellular molecules and subsequent cell death. The development of DTAC microcapsules reduced the amount of DTAC required to maintain the high standards of cleanliness and hygiene required in the food processing industries.}, } @article {pmid33521095, year = {2020}, author = {Chen, S and Feng, Z and Sun, H and Zhang, R and Qin, T and Peng, D}, title = {Biofilm-Formation-Related Genes csgD and bcsA Promote the Vertical Transmission of Salmonella Enteritidis in Chicken.}, journal = {Frontiers in veterinary science}, volume = {7}, number = {}, pages = {625049}, pmid = {33521095}, issn = {2297-1769}, abstract = {The contamination of Salmonella Enteritidis in eggs and chicken meat via vertical transmission has become a worldwide public health concern. Biofilm formation by S. Enteritidis further enhances its antibacterial resistance. However, whether genes related to biofilm formation affect the level of vertical transmission is still unclear. Here, S. Enteritidis mutants ΔcsgD, ΔcsgA, ΔbcsA, and ΔadrA were constructed from wild type strain C50041 (WT), and their biofilm-forming ability was determined by Crystal violet staining assay. Then the median lethal dose (LD50) assay was performed to determine the effects of the selected genes on virulence. The bacterial load in eggs produced by infected laying hens via the intraperitoneal pathway or crop gavage was determined for evaluation of the vertical transmission. Crystal violet staining assay revealed that S. Enteritidis mutants ΔcsgD, ΔcsgA, and ΔbcsA, but not ΔadrA, impaired biofilm formation compared with WT strain. Furthermore, the LD50 in SPF chickens showed that both the ΔcsgD and ΔbcsA mutants were less virulent compared with WT strain. Among the intraperitoneally infected laying hens, the WT strain-infected group had the highest percentage of bacteria-positive eggs (24.7%), followed by the ΔadrA group (16%), ΔcsgA group (9.9%), ΔbcsA group (4.5%), and ΔcsgD group (2.1%). Similarly, among the crop gavage chickens, the WT strain group also had the highest infection percentage in eggs (10.4%), followed by the ΔcsgA group (8.5%), ΔadrA group (7.5%), ΔbcsA group (1.9%), and ΔcsgD group (1.0%). Our results indicate that the genes csgD and bcsA help vertical transmission of S. Enteritidis in chickens.}, } @article {pmid33520594, year = {2021}, author = {Sogasu, D and Girija, ASS and Gunasekaran, S and Priyadharsini, JV}, title = {Molecular characterization and epitope-based vaccine predictions for ompA gene associated with biofilm formation in multidrug-resistant strains of A.baumannii.}, journal = {In silico pharmacology}, volume = {9}, number = {1}, pages = {15}, pmid = {33520594}, issn = {2193-9616}, abstract = {The present study was conducted to molecularly characterize the biofilm associated ompA gene from the drug resistant strains of A. baumannii and its immuno-dominant vaccine epitope predictions through immuno-informatic approach. ompA was amplified by PCR from the genomic DNA and was sequenced. Using the ORF, ompA protein sequence was retrieved and was subjected for IEDB T cell and B cell epitope analysis for the selection of the epitope peptides. Selected peptides were evaluated using appropriate servers and tools to assess the propensity for its antigenicity, solubility, physico-chemical property, toxigenicity and class-I immunogenicity. MHC class I and II restriction of HLA alleles was also performed. 48% (n = 24) of the strains possessed ompA gene. Protein structure was successfully retrieved with the selection of two epitopes viz., E1- FDGVNRGTRGTSEEGTLGNA and E2-KLSEYPNATARIEGHTDNTGPRKL. Final docking with TLR-2, showed E2 as the best epitope candidate predicted with the highest number of hydrogen bonds.}, } @article {pmid33520591, year = {2020}, author = {Schreiter, JS and Beescho, C and Kang, J and Kursawe, L and Moter, A and Kikhney, J and Langer, S and Osla, F and Wellner, E and Kurow, O}, title = {New model in diabetic mice to evaluate the effects of insulin therapy on biofilm development in wounds.}, journal = {GMS Interdisciplinary plastic and reconstructive surgery DGPW}, volume = {9}, number = {}, pages = {Doc06}, pmid = {33520591}, issn = {2193-8091}, abstract = {Objective: Diabetic patients suffer more frequently from biofilm-associated infections than normoglycemic patients. Well described in the literature is a relationship between elevated blood glucose levels in patients and the occurrence of biofilm-associated wound infections. Nevertheless, the underlying pathophysiological pathways leading to this increased infection vulnerability and its effects on biofilm development still need to be elucidated. We developed in our laboratory a model to allow the investigation of a biofilm-associated wound infection in diabetic mice under controlled insulin treatment. Methods: A dorsal skinfold chamber was used on 16 weeks old BKS.Cg-Dock7[m] +/+ Lepr[db]/J mice and a wound within the observation field of the dorsal skinfold chamber was created. These wounds were infected with Staphylococcus aureus ATCC 49230 (10[6] cells/mL). Simultaneously, we implanted implants for sustained insulin release into the ventral subcutaneous tissue (N=5 mice). Mice of the control group (N=5) were treated with sham implants. Serum glucose levels were registered before intervention and daily after the operation. Densitometrical analysis of the wound size was performed at day 0, 3, and 6 after intervention. Mice were sacrificed on day 6 and wound tissue was submitted to fluorescence in situ hybridization (FISH) and colony forming unit (CFU) analysis in addition to immunohistochemical staining to observe wound healing. Experiments were carried out in accordance with the National Institute of Health Guidelines for the Care and Use of Laboratory Animals (protocol number 05/19). Results: The insulin implants were able to reduce blood glucose levels in the mice. Hence, the diabetic mice in the intervention group were normoglycemic after the implantation. The combination with the dorsal skinfold chamber allowed for continuous, in vivo measurements of the infection development. Implantation of the insulin implant and the dorsal skinfold chamber was a tolerable condition for the diabetic mice. We succeeded to realize reproducible biofilm infections in the animals. Discussion: We developed a novel model to assess interactions between blood glucose level and S. aureus-induced biofilm-associated wound infections. The combination of the dorsal skinfold chamber model with a sustained insulin treatment has not been described so far. It allows a broad field of glucose and insulin dependent studies of infection.}, } @article {pmid33520533, year = {2020}, author = {Zubair, M}, title = {Antimicrobial and Anti-Biofilm Activities of Citrus sinensis and Moringa oleifera Against the Pathogenic Pseudomonas aeruginosa and Staphylococcus aureus.}, journal = {Cureus}, volume = {12}, number = {12}, pages = {e12337}, pmid = {33520533}, issn = {2168-8184}, abstract = {Context The plant Moringa oleifera Lam (Moringaceae), generally termed as drumstick tree, and Citrus sinensis Linn (Rutaceae) fruit have the ability to treat multiple human infections. A biofilm is none other than a complicated microbial community whose nature is greatly resistant to antimicrobial elements. The development of biofilms in abiotic and biotic surfaces has a connection with higher levels of mortality and morbidity. Along with that, it is regarded as a vital element of bacterial pathogenicity. Aim The present study evaluated the inhibitory effect and anti-biofilm activity of Moringa oleifera (M. oleifera) and Citrus sinensis (C. sinensis) extracts against those of pathogenic Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) . Materials and methods Two plant materials were collected from the local market of Tabuk city and two human pathogenic microbial strains were used in the study: S. aureus and P. aeruginosa. Further, a series of morphological, physiological, and conventional biochemical tests were performed to identify the selected microorganisms. In addition to this, the study conducted the following tests: antibiotic sensitivity test, extended-spectrum β-lactamase (ESβL), and methicillin-resistant Staphylococcus aureus (MRSA) production, biofilm formation in 96-well microtiter plates, minimum inhibitory concentration (MIC) determination, the effect of sub-MICs of C. sinensis extract and M. oleifera extract on the viability of test bacteria, and finally, measurement of the inhibition of biofilm. Results A remarkable result of the research is that the peel extract of C. sinensisand the flesh extract of M. oleifera efficiently inhibited biofilm formation by the addition of sub-inhibitory concentrations of (1/16 x MIC - 1/2 x MIC) MRSA and ESBL, respectively. P. aeruginosa shows high resistance to piperacillin (85.0%). Similarly, the resistance of MRSA was also high (65%) against gentamycin and amikacin antibiotics. Regarding ESBL, 12 (60%) isolates showed confirmed positive and 45% of S. aureus showed MRSA activity. On observing the 12 ESβL-positive P. aeruginosa, it was found that five strains (PS1, PS4, PS6, PS8, and PS11) have formed strong biofilm, methicillin-resistant S. aureus while four strains showed strong biofilm activity (SA2, SA4, SA5, and SA8). The MIC of C. sinensis extract and M. oleifera extract against strong biofilm producers had a range of 50-2000 µg/ml concentration after overnight incubation. The study results revealed that the antibiofilm activity comparatively showed the extract of M. oleifera was better than C. sinensisagainst the mixed culture (PS1+SA8, PS6+SA2, and PS8+SA4). Hence, it is recommended to use M. oleifera as an option to monitor the development of microbial biofilms or as a model for looking for better medicines. Conclusion The presence of antimicrobial activity found in M. oleifera and C. sinensis extracts offers convincing evidence of their likely action as antimicrobial metabolites against the studied microorganism. Anti-biofilm assay findings have shown that M. oleifera and C. sinensis extracts have effectively blocked MRSA and ESBL development in the biofilm matrix.}, } @article {pmid33519777, year = {2020}, author = {Liu, Y and Wu, L and Han, J and Dong, P and Luo, X and Zhang, Y and Zhu, L}, title = {Inhibition of Biofilm Formation and Related Gene Expression of Listeria monocytogenes in Response to Four Natural Antimicrobial Compounds and Sodium Hypochlorite.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {617473}, pmid = {33519777}, issn = {1664-302X}, abstract = {The aim of this study was to assess the efficacy of four natural antimicrobial compounds (cinnamaldehyde, eugenol, resveratrol and thymoquinone) plus a control chemical disinfectant (sodium hypochlorite) in inhibiting biofilm formation by Listeria monocytogenes CMCC54004 (Lm 54004) at a minimum inhibitory concentration (MIC) and sub-MICs. Crystal violet staining assay and microscopic examination were employed to investigate anti-biofilm effects of the evaluated compounds, and a real-time PCR assay was used to investigate the expression of critical genes by Lm 54004 biofilm. The results showed that five antimicrobial compounds inhibited Lm 54004 biofilm formation in a dose dependent way. Specifically, cinnamaldehyde and resveratrol showed better anti-biofilm effects at 1/4 × MIC, while sodium hypochlorite exhibited the lowest inhibitory rates. A swimming assay confirmed that natural compounds at sub-MICs suppressed Lm 54004 motility to a low degree. Supporting these findings, expression analysis showed that all four natural compounds at 1/4 × MIC significantly down-regulated quorum sensing genes (agrA, agrC, and agrD) rather than suppressing the motility- and flagella-associated genes (degU, motB, and flaA). This study revealed that sub-MICs of natural antimicrobial compounds reduced biofilm formation by suppressing the quorum sensing system rather than by inhibiting flagella formation.}, } @article {pmid33515883, year = {2021}, author = {Zhang, B and Yang, X and Liu, L and Chen, L and Teng, J and Zhu, X and Zhao, J and Wang, Q}, title = {Spatial and seasonal variations in biofilm formation on microplastics in coastal waters.}, journal = {The Science of the total environment}, volume = {770}, number = {}, pages = {145303}, doi = {10.1016/j.scitotenv.2021.145303}, pmid = {33515883}, issn = {1879-1026}, mesh = {Biofilms ; China ; Ecosystem ; Environmental Monitoring ; *Microplastics ; Plastics ; Seasons ; *Water Pollutants, Chemical/analysis ; }, abstract = {At present, microplastics (MPs) have gradually become a hot issue in marine environmental pollution and may pose a potential threat to marine ecosystems. Since MPs are not easily biodegradable, they can provide the attachment substrates for various organisms, which will affect their floating and transport, and may also lead to the invasion of harmful microorganisms. In this study, polypropylene, polyethylene, polylactic acid pellets, and glass particles were exposed for 6 weeks in different seasons at three stations in the Yellow Sea, China. The results showed that the total amounts of biofilms significantly varied among seasons and functional zones and that the temperature of seawater was the main influencing factor. A variety of biological communities (especially diatoms and bacteria) and extracellular polymeric substances were observed on the MP surfaces using scanning electron microscopy and confocal laser scanning microscopy. Sequencing analysis indicated that the structure and composition of microbial communities on MPs mainly varied with seasons and locations. In addition, most of the microorganisms were generally attached to the surface and were not any specific selection of plastic by different chemical compositions. However, the bacteria inhabiting microplastics harbored distinct metabolisms. Our results suggest that low-density MPs may settle quickly in summer in some eutrophic areas.}, } @article {pmid33515722, year = {2021}, author = {Costa, CL and Azevedo, CP and Quesada-Gómez, C and Brito, GAC and Regueira-Neto, MDS and Guedes, GMM and Rocha, MFG and Sidrim, JJC and Cordeiro, RA and Carvalho, CBM and Castelo-Branco, DSCM}, title = {Inhibitory effect of Brazilian red propolis on planktonic and biofilm forms of Clostridioides difficile.}, journal = {Anaerobe}, volume = {69}, number = {}, pages = {102322}, doi = {10.1016/j.anaerobe.2021.102322}, pmid = {33515722}, issn = {1095-8274}, mesh = {Anti-Bacterial Agents/*pharmacokinetics ; Biofilms/*drug effects ; Brazil ; Clostridioides difficile/*drug effects ; Microbial Sensitivity Tests ; Plankton/*drug effects ; Propolis/*chemistry/*pharmacokinetics ; Vancomycin/*pharmacokinetics ; }, abstract = {Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacillus which is the leading cause of health-care-associated infective diarrhea. The rising incidence of antibiotic resistance in pathogens such as C. difficile makes researches on alternative antibacterial products very important, especially those exploring natural products like propolis. Brazilian Red Propolis, found in the Northeast region of Brazil, is composed by products from regional plants that have the antimicrobial properties. This study aimed to evaluate the in vitro activity of Brazilian Red Propolis (BRP) against C. difficile strains in planktonic and biofilm forms. The susceptibility of four strains of C. difficile to BRP was analyzed by broth microdilution method and vancomycin was included as control drug. BRP-exposed C. difficile cells were evaluated by scanning electron microscopy (SEM). Then, the effects of BRP on growing and mature C. difficile biofilms were also evaluated. BRP minimum inhibitory concentration was 625 μg/mL against all tested strains, while vancomycin MIC range was 0.5-2 μg/mL. SEM showed the loss of homogeneity in bacterial cell wall and cell fragmentation, after BRP-exposure. BRP, at MIC, reduced (P < 0.05) the biomass, matrix proteins and matrix carbohydrates of growing biofilms, and, at 8xMIC, reduced (P < 0.05) the biomass and matrix proteins of mature biofilms. The present study demonstrated that BRP inhibits planktonic growth, damages cell wall, decreases biofilm growth and harms mature biofilms of C. difficile.}, } @article {pmid33513982, year = {2021}, author = {Gargouch, N and Elleuch, F and Karkouch, I and Tabbene, O and Pichon, C and Gardarin, C and Rihouey, C and Picton, L and Abdelkafi, S and Fendri, I and Laroche, C}, title = {Potential of Exopolysaccharide from Porphyridium marinum to Contend with Bacterial Proliferation, Biofilm Formation, and Breast Cancer.}, journal = {Marine drugs}, volume = {19}, number = {2}, pages = {}, pmid = {33513982}, issn = {1660-3397}, mesh = {Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; *Breast Neoplasms/drug therapy ; Cell Line, Tumor ; Cell Survival/*drug effects/physiology ; Dose-Response Relationship, Drug ; Female ; Mice ; Microalgae/isolation & purification ; Microbial Sensitivity Tests/methods ; Polysaccharides, Bacterial/isolation & purification/*pharmacology/therapeutic use ; *Porphyridium/isolation & purification ; }, abstract = {Exopolysaccharide (EPS) from marine microalgae are promising sources of a new generation of drugs. However, lot of them remain to be discovered and tested. In this study, EPS produced by Porphyridium marinum and its oligomers prepared by High Pressure Homogenizer have been tested for different biological activities, i.e., antibacterial, anti-fungal and antibiofilm activities on Candida albicans, as well as for their effects on the viability of murine breast cancer cells. Results have shown that all EPS samples present some biological activity. For antibacterial and antibiofilm activities, the native EPS exhibited a better efficiency with Minimum Inhibitory Concentration (MIC) from 62.5 µg/mL to 1000 µg/mL depending on the bacterial strain. For Candida albicans, the biofilm formation was reduced by about 90% by using only a 31.3 µg/mL concentration. Concerning breast cancer cells, lower molar masses fractions appeared to be more efficient, with a reduction of viability of up to 55%. Finally, analyses of polymers composition and viscosity measurements were conducted on all samples, in order to propose hypotheses involving the activities caused by the intrinsic properties of polymers.}, } @article {pmid33513933, year = {2021}, author = {Ratajczak, M and Kaminska, D and Dlugaszewska, J and Gajecka, M}, title = {Antibiotic Resistance, Biofilm Formation, and Presence of Genes Encoding Virulence Factors in Strains Isolated from the Pharmaceutical Production Environment.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33513933}, issn = {2076-0817}, support = {grant no. 502-14-03301402-09911.//This work was supported, in part, by the Poznan University of Medical Sciences, grant no. 502-14-03301402-09911./ ; }, abstract = {The spread of bacterial resistance to antibiotics affects various areas of life. The aim of this study was to assess the occurrence of Pseudomonas aeruginosa, and other bacteria mainly from orders Enterobacterales and Staphylococcus in the pharmaceutical production sites, and to characterize isolated strains in the aspects of antibiotic resistance, biofilm formation, and presence of genes encoding virulence factors. Genes encoding selected virulence factors were detected using PCR techniques. Antimicrobial susceptibility testing was applied in accordance with the EUCAST recommendations. A total of 46 P. aeruginosa strains were isolated and 85% strains showed a strong biofilm-forming ability. The qualitative identification of genes taking part in Quorum Sensing system demonstrated that over 89% of strains contained lasR and rhlI genes. An antimicrobial susceptibility testing revealed nine strains resistant to at least one antibiotic, and two isolates were the metallo-β-lactamase producers. Moreover, the majority of P. aeruginosa strains contained genes encoding various virulence factors. Presence of even low level of pathogenic microorganisms or higher level of opportunistic pathogens and their toxic metabolites might result in the production inefficiency. Therefore, the prevention of microbial contamination, effectiveness of sanitary and hygienic applied protocols, and constant microbiological monitoring of the environment are of great importance.}, } @article {pmid33513680, year = {2021}, author = {Marchianò, V and Salvador, M and Moyano, A and Gutiérrez, G and Matos, M and Yáñez-Vilar, S and Piñeiro, Y and Rivas, J and Martínez-García, JC and Peddis, D and Blanco-López, MC and Rivas, M and Ditaranto, N and Cioffi, N}, title = {Electrodecoration and Characterization of Superparamagnetic Iron Oxide Nanoparticles with Bioactive Synergistic Nanocopper: Magnetic Hyperthermia-Induced Ionic Release for Anti-Biofilm Action.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33513680}, issn = {2079-6382}, abstract = {The urgency for the availability of new antibacterial/disinfectant agents has become a worldwide priority. At the same time, along with the extensive use of other metal nanoparticles (NPs), the investigation of magnetic NPs (MNPs) in antibacterial studies has turned out to be an increasingly attractive research field. In this context, we present the preparation and characterization of superparamagnetic iron oxide NPs, electrodecorated with antimicrobial copper NPs, able to modulate the release of bioactive species not only by the NP's stabilizer, but also through the application of a suitable magnetic field. Antimicrobial synergistic CuNPs stabilized by benzalkonium chloride have been used in the current study. We demonstrate the successful preparation of Cu@Fe3O4 MNPs composites through morphological and spectroscopic results. Additionally, an extensive magnetic characterization is reported, along with hyperthermia-induced copper ionic release. On the basis of our results, we propose a new generation of antimicrobial magnetic nanomaterials, whose bioactivity can be also tuned by the application of a magnetic field.}, } @article {pmid33512576, year = {2021}, author = {Fekrirad, Z and Darabpour, E and Kashef, N}, title = {Eradication of Acinetobacter baumannii Planktonic and Biofilm Cells Through Erythrosine-Mediated Photodynamic Inactivation Augmented by Acetic Acid and Chitosan.}, journal = {Current microbiology}, volume = {78}, number = {3}, pages = {879-886}, pmid = {33512576}, issn = {1432-0991}, mesh = {Acetic Acid/pharmacology ; *Acinetobacter baumannii ; Biofilms ; *Chitosan/pharmacology ; Erythrosine/pharmacology ; Humans ; Photosensitizing Agents/pharmacology ; Plankton ; }, abstract = {Photodynamic inactivation (PDI) is an attractive treatment modality for multidrug-resistant bacterial infections. The effectiveness of photosensitization by anionic photosensitizers such as erythrosine B can be further enhanced by the addition of biological or chemical molecules. This study aimed to investigate of the enhancement effect of acetic acid and chitosan on erythrosine-mediated PDI of Acinetobacter baumannii in planktonic and biofilm forms. The planktonic cell growth of three A. baumannii strains was subjected to PDI by using erythrosine B (50 µM) in 0.01% acetic acid and green laser light (530 nm) at fluence of 40 J/cm[2]. The phototoxic effect of erythrosine B (100 µM) in combination with chitosan (12.5 mg/ml) (in a solution of acetic acid) at fluence of 80 J/cm2 on biofilms was also evaluated. Finally, the cytotoxicity and phototoxicity of the mentioned mixture were assessed on human fibroblasts. Planktonic cells of all three studied A. baumannii strains were almost eradicated by erythrosine B-mediated PDI in the presence of acetic acid. Also, PDI combined with chitosan resulted in a marked decrease in the number of viable biofilm cells (> 3 log10 CFU). At the same experimental conditions, only 15% of the fibroblasts were photoinactivated. The results showed that PDI by using erythrosine B in acetic acid is very effective against A. baumannii planktonic cells and could eliminate them significantly. Also, chitosan enhanced the anti-biofilm efficacy of erythrosine B-mediated PDI against A. baumannii, suggesting that combination therapy may be useful in targeting biofilms.}, } @article {pmid33512424, year = {2021}, author = {Jewell, ML and Bionda, N and Moran, AV and Bevels, EJ and Jewell, HL and Hariri, S and Leung, BK}, title = {In Vitro Evaluation of Common Antimicrobial Solutions Used for Breast Implant Soaking and Breast Pocket Irrigation-Part 2: Efficacy Against Biofilm-Associated Bacteria.}, journal = {Aesthetic surgery journal}, volume = {41}, number = {11}, pages = {1252-1262}, pmid = {33512424}, issn = {1527-330X}, support = {//Allergan Aesthetics/ ; //AbbVie company/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; Humans ; Staphylococcus epidermidis ; }, abstract = {BACKGROUND: Biofilm-associated bacteria have been observed in both breast implant revision and tissue expander-implant exchange surgeries. The utilization of antimicrobial solutions in breast surgery, especially those containing triple antibiotics (TAB) and/or 10% povidone-iodine (PI), may help reduce existing biofilm-associated bacteria, which is particularly important in a mature breast pocket that may contain residual bacteria from a previously colonized implant surface or, theoretically, bacteria that may arrive postoperatively through hematogenous spread.

OBJECTIVES: A series of in vitro assessments was performed to evaluate the antimicrobial utility of TAB and PI, either alone or in combination, against preformed biofilm-associated bacteria.

METHODS: Preformed biofilm-associated gram-positive and gram-negative bacterial strains were exposed to TAB and PI ± TAB for up to 30 minutes in a bacterial time-kill assay. Efficacy of various dilutions of PI and the effects of serum protein on PI efficacy were also investigated.

RESULTS: TAB was ineffective at the timeframes tested when utilized alone; when utilized in conjunction with PI, significant log reduction of all biofilm-associated bacterial species tested was achieved when treated for at least 5 minutes. PI alone at a concentration of 25% or higher was also effective, although its efficacy was negatively affected by increasing serum protein concentration only for Staphylococcus epidermidis.

CONCLUSIONS: Our data indicate that PI-containing solutions significantly reduce biofilm-associated bacteria, suggesting potential utility for breast pocket irrigation during revision or exchange surgeries. Care should be taken to minimize excessive dilution of PI to maintain efficacy.}, } @article {pmid33511774, year = {2021}, author = {Ma, N and Sun, C}, title = {Cadmium sulfide nanoparticle biomineralization and biofilm formation mediate cadmium resistance of the deep-sea bacterium Pseudoalteromonas sp. MT33b.}, journal = {Environmental microbiology reports}, volume = {13}, number = {3}, pages = {325-336}, doi = {10.1111/1758-2229.12933}, pmid = {33511774}, issn = {1758-2229}, mesh = {Biodegradation, Environmental ; Biofilms ; Biomineralization ; Cadmium/toxicity ; Cadmium Compounds ; Ecosystem ; *Nanoparticles ; *Pseudoalteromonas/genetics/metabolism ; Sulfides ; }, abstract = {Cadmium (Cd) is a common toxic heavy metal in the environment, and bacteria have evolved different strategies to deal with Cd toxicity. Here, a bacterium designated Pseudoalteromonas sp. MT33b possessing strong Cd resistance was isolated from the Mariana Trench sediments. Supplement of cysteine significantly increased bacterial Cd resistance and removal rate. Biofilm formation was demonstrated to play a positive role toward bacterial Cd resistance. Transcriptome analysis showed the supplement of cysteine effectively prevented Cd[2+] from entering bacterial cells, promoted saccharide metabolism and thereby facilitating energy production, which consists well with bacterial growth trend analysed under the same conditions. Notably, the expressions of many biofilm formation related genes including flagellar assembly, signal transduction, bacterial secretion and TonB-dependent transfer system were significantly upregulated when facing Cd stress, indicating their important roles in determining bacterial biofilm formation and enhancing Cd resistance. Overall, this study indicates the formation of insoluble CdS precipitates and massive biofilm is the major strategy adopted by Pseudoalteromonas sp. MT33b to eliminate Cd stress. Our results provide a good model to investigate how heavy metals impact biofilm formation in the deep-sea ecosystems, which may facilitate a deeper understanding of microbial environmental adaptability and better utilization of these microbes for bioremediation purposes in the future.}, } @article {pmid33511211, year = {2021}, author = {Tiwari, SK and Wang, S and Huang, Y and Zhou, X and Xu, HHK and Ren, B and Peng, X and Xiao, Y and Li, M and Cheng, L}, title = {Starvation Survival and Biofilm Formation under Subminimum Inhibitory Concentration of QAMs.}, journal = {BioMed research international}, volume = {2021}, number = {}, pages = {8461245}, pmid = {33511211}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/microbiology ; Biofilms/*drug effects ; Dental Pulp Cavity/microbiology ; Dental Pulp Diseases/microbiology ; Drug Resistance, Bacterial/*drug effects ; Enterococcus faecalis/drug effects/genetics ; Humans ; Lactic Acid/metabolism ; Lactobacillus acidophilus/drug effects/genetics ; Methacrylates/*pharmacology ; Methylamines ; Microbial Sensitivity Tests ; Quaternary Ammonium Compounds/*pharmacology ; Streptococcus gordonii/drug effects/genetics ; }, abstract = {Quaternary ammonium methacrylates (QAMs) are useful antimicrobial compounds against oral bacteria. Here, we investigated the effects of two QAMs, dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM), on biofilm formation, survival and development of tolerance by biofilm, and survival and development of tolerance against QAMs after prolonged starvation. Enterococcus faecalis (E. faecalis), Streptococcus gordonii (S. gordonii), Lactobacillus acidophilus (L. acidophilus), and Actinomyces naeslundii (A. naeslundii) were used. Minimum inhibitory concentration (MIC) of QAMs against multispecies biofilm was determined. Biofilm formed under sub-MIC was observed by crystal violet staining and confocal laser scanning microscopy (CLSM). Metabolic activity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid production measurement. Development of tolerance was determined by MIC values before and after exposure to QAMs or after prolonged starvation. It was found that E. faecalis and S. gordonii could survive and form biofilm under sub-MIC of QAMs. Lactic acid production from biofilms formed under sub-MIC was significantly higher than control specimens (p < 0.05). The exposure to sub-MIC of QAMs promoted biofilm formation, and prolonged starvation or prolonged contact with sub-MIC helped bacteria develop tolerance against killing by QAMs.}, } @article {pmid33510721, year = {2020}, author = {Zhang, J and Liang, X and Zhang, S and Song, Z and Wang, C and Xu, Y}, title = {Maipomycin A, a Novel Natural Compound With Promising Anti-biofilm Activity Against Gram-Negative Pathogenic Bacteria.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {598024}, pmid = {33510721}, issn = {1664-302X}, abstract = {Pathogenic bacterial biofilms play an important role in recurrent nosocomial and medical device-related infections. Once occurred, the complex structure of the biofilm promotes the development of antibiotic resistance and becomes extremely difficult to eradicate. Here we describe a novel and effective anti-biofilm compound maipomycin A (MaiA), which was isolated from the metabolites of a rare actinomycete strain Kibdelosporangium phytohabitans XY-R10. Its structure was deduced from analyses of spectral data and confirmed by single-crystal X-ray crystallography. This natural product demonstrated a broad spectrum of anti-biofilm activities against Gram-negative bacteria. Interestingly, the addition of Fe(II) or Fe(III) ions could block the biofilm inhibition activity of MaiA because it is an iron chelator. However, not all iron chelators showed biofilm inhibition activity, suggesting that MaiA prevents biofilm formation through a specific yet currently undefined pathway. Furthermore, MaiA acts as a synergist to enhance colistin efficacy against Acinetobacter baumannii. Our results indicate that MaiA may potentially serve as an effective antibiofilm agent to prevent Gram-negative biofilm formation in future clinical applications.}, } @article {pmid33509506, year = {2021}, author = {Zhang, L and Zhu, C and Chen, X and Xu, X and Wang, H}, title = {Resistance of detached-cells of biofilm formed by Staphylococcus aureus to ultra high pressure homogenization.}, journal = {Food research international (Ottawa, Ont.)}, volume = {139}, number = {}, pages = {109954}, doi = {10.1016/j.foodres.2020.109954}, pmid = {33509506}, issn = {1873-7145}, mesh = {*Biofilms ; Food Handling ; Plankton ; *Staphylococcus aureus ; }, abstract = {Staphylococcus aureus is one of the main pathogens contributing to foodborne outbreaks, owing in part to its ability to form biofilms on food-contact surfaces. Cells that can detach from mature biofilms are a source for microbial cross-contamination in liquid food systems. The study was to evaluate and compare the resistance of detached-cells of biofilm formed by S. aureus and planktonic cells to Ultra High Pressure Homogenization (UHPH), a non-thermal technology applied in food processing. The results showed that the survival of both detached-cells and planktonic cells was dependent upon the applied pressure ranging from 30,000 PSI to 40,000 PSI, and cycle numbers with 1 and 3. A significant difference in UHPH resistance was observed at pressures of 35,000 PSI to 40,000 PSI whereby planktonic cell numbers were reduced about 2.0 log CFU/mL compared to a 0.5 log CFU/mL reduction of detached-cells. Cell resistance was further evaluated following UHPH by measuring membrane integrity and potential, as well as observing the cells using scanning electron microscopy (SEM). SEM images revealed more scattered exopolysaccharides in the biofilm after UHPH treatment compared to the control. Additionally, UHPH treatment resulted in planktonic cells having a greater shift to smaller cell size and a wider cell size distribution compared with detached-cells; this indicated a higher resistance of detached-cells to UHPH. This finding suggests that although UHPH has great potential application in food sterilization, the resistance of detached-cells cannot be ignored.}, } @article {pmid33508090, year = {2021}, author = {Wu, L and Liu, Y and Dong, P and Zhang, Y and Mao, Y and Liang, R and Yang, X and Zhu, L and Luo, X}, title = {Beef-Based Medium Influences Biofilm Formation of Escherichia coli O157:H7 Isolated from Beef Processing Plants.}, journal = {Journal of food protection}, volume = {84}, number = {6}, pages = {1060-1068}, doi = {10.4315/JFP-20-385}, pmid = {33508090}, issn = {1944-9097}, mesh = {Animals ; Biofilms ; Cattle ; Colony Count, Microbial ; Culture Media ; *Escherichia coli O157 ; *Escherichia coli Proteins ; RNA-Binding Proteins ; Repressor Proteins ; Temperature ; }, abstract = {ABSTRACT: Beef-based medium beef extract (BE) and standard medium tryptic soy broth (TSB) are used as minimally processed food models to study the effects on Escherichia coli O157:H7 biofilm formation. The effects of temperatures (4, 10, 25, 37, and 42°C), pH values (4.5, 5.0, 5.5, 6.0, 7.0, and 8.0), strain characteristics, and the expression of functional genes on the biofilm formation ability of the bacteria were determined. The three tested E. coli O157:H7 strains produced biofilm in both media. Biofilm formation was greater in BE than in TSB (P < 0.05). The strongest biofilm formation capacity of E. coli O157:H7 was achieved at 37°C and pH 7.0. Biofilm formation was significantly inhibited for three tested strains incubated at 4°C. Biofilm formation ability was correlated with swarming in TSB. Biofilm formation was significantly and positively correlated with autoaggregation or hydrophobicity in BE (P < 0.05). At the initial stage of biofilm formation, the expressions of luxS, sdiA, csgD, csgA, flhC, adrA, and rpoS were significantly higher in BE than in TSB (P < 0.05). At the maturity stage, the expressions of luxS, sdiA, csgD, csgA, flhC, csrA, adrB, adrA, iraM, and rpoS were significantly higher in TSB than in BE (P < 0.05). Such information could help in the development of effective biofilm removal technologies to deal with risks of E. coli O157:H7 biofilms in the beef industry.}, } @article {pmid33507414, year = {2021}, author = {Hemdan, BA and El-Taweel, GE and Goswami, P and Pant, D and Sevda, S}, title = {The role of biofilm in the development and dissemination of ubiquitous pathogens in drinking water distribution systems: an overview of surveillance, outbreaks, and prevention.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {2}, pages = {36}, pmid = {33507414}, issn = {1573-0972}, support = {BSBEPDxDBT00389BAM001/19-1436//DBT-TWAS Postdoctoral Fellowship programme/ ; }, mesh = {Biofilms/*growth & development ; Drinking Water/*microbiology ; Humans ; Population Surveillance ; Public Health ; Waterborne Diseases/epidemiology/*microbiology/prevention & control ; }, abstract = {A variety of pathogenic microorganisms can survive in the drinking water distribution systems (DWDS) by forming stable biofilms and, thus, continually disseminating their population through the system's dynamic water bodies. The ingestion of the pathogen-contaminated water could trigger a broad spectrum of illnesses and well-being-related obstacles. These waterborne diseases are a significant concern for babies, pregnant women, and significantly low-immune individuals. This review highlights the recent advances in understanding the microbiological aspects of drinking water quality, biofilm formation and its dynamics, health issues caused by the emerging microbes in biofilm, and approaches for biofilm investigation its prevention and suppression in DWDS.}, } @article {pmid33506609, year = {2021}, author = {Dong, HH and Wang, YH and Peng, XM and Zhou, HY and Zhao, F and Jiang, YY and Zhang, DZ and Jin, YS}, title = {Synergistic antifungal effects of curcumin derivatives as fungal biofilm inhibitors with fluconazole.}, journal = {Chemical biology & drug design}, volume = {97}, number = {5}, pages = {1079-1088}, doi = {10.1111/cbdd.13827}, pmid = {33506609}, issn = {1747-0285}, support = {2020ZX09721001-006-003//Major new drug development for Major scientific and technological projects of the Ministry of Science and Technology/ ; 81830106//National Natural Science Foundation of China/ ; FH2016066//Innovative Practice of Undergraduate Project of Second Military Medical University/ ; FH2017104//Innovative Practice of Undergraduate Project of Second Military Medical University/ ; }, mesh = {Adenosine Triphosphate/metabolism ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/drug effects/metabolism/physiology ; Cell Line ; Cell Membrane Permeability/drug effects ; Cell Survival/drug effects ; Curcumin/*analogs & derivatives/pharmacology ; Drug Resistance, Fungal/drug effects ; Drug Synergism ; Fluconazole/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Structure-Activity Relationship ; }, abstract = {Lack of novel antifungal agents and severe drug resistance has led to high incidence and associated mortality of invasive fungal infections. To tackle the challenges, novel antifungal agents with anti-resistant potency are highly desirable. Thus, derivatives of curcumin were synthesized to restore the effectiveness of fluconazole (FLC) against FLC-resistant Candida spp. and structure-activity relationships were then discussed. Some novel derivatives showed promising features as novel antifungal lead compounds. Of them, compound 4 showed good alone or synergistic antifungal activity against FLC-resistant Candida spp. Moreover, compound 4 was proven as a potent inhibitor of Candida albicans biofilm formation and yeast-to-hypha morphological transition whether used alone or in combination with FLC, which was further confirmed by the inhibitory effect on cellular surface hydrophobicity of C. albicans. Compound 4 also inhibits intracellular ATP production of C. albicans and disrupts membrane permeability of C. albicans when used in combination with FLC. The results highlighted the potential of curcumin derivatives to overcome fluconazole-related and biofilm-related drug resistance.}, } @article {pmid33505771, year = {2021}, author = {Tabbasum, K and Reddy, DS and Singh, V and Subasri, R and Garg, P}, title = {Sol-Gel Nanocomposite Coatings for Preventing Biofilm Formation on Contact Lens Cases.}, journal = {Translational vision science & technology}, volume = {10}, number = {1}, pages = {4}, pmid = {33505771}, issn = {2164-2591}, mesh = {Biofilms ; *Contact Lenses/adverse effects ; Humans ; *Metal Nanoparticles ; *Nanocomposites ; Silver/pharmacology ; }, abstract = {PURPOSE: To evaluate the efficacy of a nanosilver-based sol-gel coating in preventing biofilm formation on contact lens cases.

METHODS: An organic-inorganic hybrid silica-zirconia sol formulation with immobilized silver nanoparticles was deposited on contact lens case coupons. The coated and uncoated coupons were subjected to biofilm formation to Gram-negative and Gram-positive keratitis isolates and ATCC strains using a standard protocol. The biofilms were evaluated using crystal violet, MTT assay, and scanning electron microscope (SEM) examination. The duration of efficacy of the coating was evaluated by exposing the coated and uncoated coupons to a multipurpose lens cleaning solution for various durations up to 30 days and comparing their biofilm characteristics. The cytotoxicity of the coated surface was assessed using cell culture studies.

RESULTS: Cross-hatch tests and SEM confirmed the presence of a uniform, well-adhered coating on the surface. The coating resulted in a nearly 95% reduction in biofilm formation of the tested bacteria and was effective despite exposures of up to 30 days to a multipurpose lens cleaning solution. The coating did not exhibit cytotoxicity to human corneal epithelial cells.

CONCLUSIONS: The silver nanoparticle-based coating exhibits a good antibiofilm property for both Gram-negative bacilli and Gram-positive cocci and is promising for commercial use in preventing contact lens-related infections.

TRANSLATIONAL RELEVANCE: Biofilm formation on lens cases continues to be an important concern. The proposed coating will help reduce such formations, thus reducing the risk of lens-associated microbial keratitis.}, } @article {pmid33505622, year = {2020}, author = {Bozkurt, AP and Ünlü, Ö and Demirci, M}, title = {Comparison of microbial adhesion and biofilm formation on orthodontic wax materials; an in vitro study.}, journal = {Journal of dental sciences}, volume = {15}, number = {4}, pages = {493-499}, pmid = {33505622}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: Orthodontic wax materials are available on the dental market and are given by orthodontists due to pain, sores and irritation caused by treatment. The aim of the study was to compare biofilm formation and microbial adhesion at different time points on different protective materials used against orthodontic wounds in vitro.

MATERIALS AND METHODS: Microbial adhesion and biofilm formation were evaluated against Streptococcus mutans ATCC 25175 and Lactobacillus acidophilus ATCC 4356 standard strains on orthodontic wax materials at the 0, 24th, 48th, 72nd, 96th and 120th hour. The Kruskal Wallis test and Bonferroni test were used for statistical evaluations. Statistical significance was set at p < 0.05.

RESULTS: It was observed that S. mutans formed statistically significantly more biofilm on OrthoDots®CLEAR (OrVance) than Ora-Aid (TBM Corporation) at the 48th hour (p < 0.05). Furthermore, L. acidophilus formed statistically significantly more biofilm on OrthoDots®CLEAR (OrVance) than Brace Gard®(Infa-Lab Inc.) at the 72nd, 96th and 120th hours (p < 0.05).

CONCLUSION: Significant differences were noted among the different orthodontic wax materials and both S. mutans and L. acidophilus created biofilm on all waxes at different time points in vitro. To prevent biofilm formation, these waxes need to be refreshed and should not be used for more than 24 h. According to our study, biofilm production performances of pathogens on Brace Gard®(Infa-Lab Inc.) are minimal and therefore it may be a better option to use in clinics. However, to our knowledge, this is the first study investigating biofilm formation on waxes and more studies are needed in this field.}, } @article {pmid33505365, year = {2020}, author = {Siddam, AD and Zaslow, SJ and Wang, Y and Phillips, KS and Silverman, MD and Regan, PM and Amarasinghe, JJ}, title = {Characterization of Biofilm Formation by Mycobacterium chimaera on Medical Device Materials.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {586657}, pmid = {33505365}, issn = {1664-302X}, abstract = {Non-tuberculous mycobacteria (NTM) are widespread in the environment and are a public health concern due to their resistance to antimicrobial agents. The colonization of surgical heater-cooler devices (HCDs) by the slow-growing NTM species Mycobacterium chimaera has recently been linked to multiple invasive infections in patients worldwide. The resistance of M. chimaera to antimicrobials may be aided by a protective biofilm matrix of extracellular polymeric substances (EPS). This study explored the hypothesis that M. chimaera can form biofilms on medically relevant materials. Several M. chimaera strains, including two HCD isolates, were used to inoculate a panel of medical device materials. M. chimaera colonization of the surfaces was monitored for 6 weeks. M. chimaera formed a robust biofilm at the air-liquid interface of borosilicate glass tubes, which increased in mass over time. M. chimaera was observed by 3D Laser Scanning Microscopy to have motility during colonization, and form biofilms on stainless steel, titanium, silicone and polystyrene surfaces during the first week of inoculation. Scanning electron microscopy (SEM) of M. chimaera biofilms after 4 weeks of inoculation showed that M. chimaera cells were enclosed entirely in extracellular material, while cryo-preserved SEM samples further revealed that an ultrastructural component of the EPS matrix was a tangled mesh of 3D fiber-like projections connecting cells. Considering that slow-growing M. chimaera typically has culture times on the order of weeks, the microscopically observed ability to rapidly colonize stainless steel and titanium surfaces in as little as 24 h after inoculation is uncharacteristic. The insights that this study provides into M. chimaera colonization and biofilm formation of medical device materials are a significant advance in our fundamental understanding of M. chimaera surface interactions and have important implications for research into novel antimicrobial materials, designs and other approaches to help reduce the risk of infection.}, } @article {pmid33505163, year = {2021}, author = {Tian, F and Li, J and Nazir, A and Tong, Y}, title = {Bacteriophage - A Promising Alternative Measure for Bacterial Biofilm Control.}, journal = {Infection and drug resistance}, volume = {14}, number = {}, pages = {205-217}, pmid = {33505163}, issn = {1178-6973}, abstract = {Bacterial biofilms can enhance bacteria's viability by providing resistance against antibiotics and conventional disinfectants. The existence of biofilm is a serious threat to human health, causing incalculable loss. Therefore, new strategies to deal with bacterial biofilms are needed. Bacteriophages are unique due to their activity on bacteria and do not pose a threat to humans. Consequently, they are considered safe alternatives to drugs for the treatment of bacterial diseases. They can effectively obliterate bacterial biofilms and have great potential in medical treatment, the food industry, and pollution control. There are intricate mechanisms of interaction between phages and biofilms. Biofilms may prevent the invasion of phages, and phages can kill bacteria for biofilm control purposes or influence the formation of biofilms. At present, there are various measures for the prevention and control of biofilms through phages, including the combined use of drugs and the application of phage cocktails. This article mainly reviews the function and formation process of bacterial biofilms, summarizes the different mechanisms between phages and biofilms, briefly explains the phage usage for the control of bacterial biofilms, and promotes phage application maintenance human health and the protection of the natural environment.}, } @article {pmid33505094, year = {2021}, author = {Lee, N and Kim, MD and Lim, MC}, title = {Autoinducer-2 Could Affect Biofilm Formation by Food-Derived Bacillus cereus.}, journal = {Indian journal of microbiology}, volume = {61}, number = {1}, pages = {66-73}, pmid = {33505094}, issn = {0046-8991}, abstract = {Bacillus cereus is a foodborne pathogen and cause a frequent problem due to the biofilms forming in equipment of food production plants. Autoinducer-2 (AI-2) involved in interspecies communication, plays a role in the biofilm formation of B. cereus. In this study, biofilm formation by thirty-nine B. cereus strains isolated from foods produced in Korea was determined. To investigate the effect of AI-2 on biofilm formation by B. cereus SBC27, which had the highest biofilm-forming ability, biofilm densities formed after addition of the AI-2 from Staphylococcus aureus and Escherichia coli were analysed. As a result, it was found that the quorum sensing molecule AI-2 could induce biofilm formation by B. cereus within 24 h, but it may also inhibit biofilm formation when more AI-2 is added after 24 h. Thus, these results improve our understanding of biofilm formation by food-derived B. cereus and provide clues that could help to reduce the impact of biofilms, the biggest problem in food processing environments, which has an impact on public health as well as the economy.}, } @article {pmid33504806, year = {2021}, author = {Martín-Rodríguez, AJ and Reyes-Darias, JA and Martín-Mora, D and González, JM and Krell, T and Römling, U}, title = {Reduction of alternative electron acceptors drives biofilm formation in Shewanella algae.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {9}, pmid = {33504806}, issn = {2055-5008}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Dimethyl Sulfoxide/pharmacology ; *Electrons ; Gene Expression Regulation, Bacterial/drug effects ; Mutation ; Nitrates/pharmacology ; Oxidation-Reduction/drug effects ; Oxidoreductases/genetics/metabolism ; Shewanella/drug effects/isolation & purification/*physiology ; Signal Transduction/drug effects ; }, abstract = {Shewanella spp. possess a broad respiratory versatility, which contributes to the occupation of hypoxic and anoxic environmental or host-associated niches. Here, we observe a strain-specific induction of biofilm formation in response to supplementation with the anaerobic electron acceptors dimethyl sulfoxide (DMSO) and nitrate in a panel of Shewanella algae isolates. The respiration-driven biofilm response is not observed in DMSO and nitrate reductase deletion mutants of the type strain S. algae CECT 5071, and can be restored upon complementation with the corresponding reductase operon(s) but not by an operon containing a catalytically inactive nitrate reductase. The distinct transcriptional changes, proportional to the effect of these compounds on biofilm formation, include cyclic di-GMP (c-di-GMP) turnover genes. In support, ectopic expression of the c-di-GMP phosphodiesterase YhjH of Salmonella Typhimurium but not its catalytically inactive variant decreased biofilm formation. The respiration-dependent biofilm response of S. algae may permit differential colonization of environmental or host niches.}, } @article {pmid33504794, year = {2021}, author = {Flemming, HC and Baveye, P and Neu, TR and Stoodley, P and Szewzyk, U and Wingender, J and Wuertz, S}, title = {Who put the film in biofilm? The migration of a term from wastewater engineering to medicine and beyond.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {10}, pmid = {33504794}, issn = {2055-5008}, mesh = {*Biofilms ; Extracellular Polymeric Substance Matrix ; Microbial Consortia ; Terminology as Topic ; }, abstract = {Sessile microorganisms were described as early as the seventeenth century. However, the term biofilm arose only in the 1960s in wastewater treatment research and was adopted later in marine fouling and in medical and dental microbiology. The sessile mode of microbial life was gradually recognized to be predominant on Earth, and the term biofilm became established for the growth of microorganisms in aggregates, frequently associated with interfaces, although many, if not the majority, of them not being continuous "films" in the strict sense. In this sessile form of life, microorganisms live in close proximity in a matrix of extracellular polymeric substances (EPS). They share emerging properties, clearly distinct from solitary free floating planktonic microbial cells. Common characteristics include the formation of synergistic microconsortia, using the EPS matrix as an external digestion system, the formation of gradients and high biodiversity over microscopically small distances, resource capture and retention, facilitated gene exchange as well as intercellular communication, and enhanced tolerance to antimicrobials. Thus, biofilms belong to the class of collective systems in biology, like forests, beehives, or coral reefs, although the term film addresses only one form of the various manifestations of microbial aggregates. The uncertainty of this term is discussed, and it is acknowledged that it will not likely be replaced soon, but it is recommended to understand these communities in the broader sense of microbial aggregates.}, } @article {pmid33504089, year = {2021}, author = {Scotti, R and Stringaro, A and Nicolini, L and Zanellato, M and Boccia, P and Maggi, F and Gabbianelli, R}, title = {Effects of Essential Oils from Cymbopogon spp. and Cinnamomum verum on Biofilm and Virulence Properties of Escherichia coli O157:H7.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33504089}, issn = {2079-6382}, abstract = {Every year, the pharmaceutical and food industries produce over 1000 tons of essential oils (EOs) exploitable in different fields as the development of eco-friendly and safe antimicrobial inhibitors. In this work we investigated the potential of some EOs, namely Cinnamomum verum, Cymbopogon martini, Cymbopogoncitratus and Cymbopogon flexuosus, on the growth, biofilm formation and gene expression in four strains of enterohemorrhagic Escherichia coli O157:H7. All EOs were analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity was performed by using dilutions of EOs ranging from 0.001 to 1.2% (v/v). Subinhibitory doses were used for biofilm inhibition assay. The expression profiles were obtained by RT-PCR. E. coli O157:H7 virulence was evaluated in vivo in the nematode Caenorhabditis elegans. All EOs showed minimal inhibitory concentrations (MICs) ranging from 0.0075 to 0.3% (v/v). Cinnamomum verum bark EO had the best activity (MIC of 0.0075% (v/v) in all strains) while the C. verum leaf EO had an intermediate efficacy with MIC of 0.175% (v/v) in almost all strains. The Cymbopogon spp. showed the more variable MICs (ranging from 0.075 to 0.3% (v/v)) depending on the strain used. Transcriptional analysis showed that C. martini EO repressed several genes involved in biofilm formation, virulence, zinc homeostasis and encoding some membrane proteins. All EOs affected zinc homeostasis, reducing ykgM and zinT expression, and reduced the ability of E. coli O157:H7 to infect the nematode C. elegans. In conclusion, we demonstrated that these EOs, affecting E. coli O157:H7 infectivity, have a great potential to be used against infections caused by microorganisms.}, } @article {pmid33502955, year = {2022}, author = {Azevedo, CS and Correa, CZ and Lopes, DD and Pescim, RR and Prates, KVMC and Barana, AC}, title = {Aeration and non-aeration cycles (AE/NA) time: influence in combined organic matter and nitrogen removal and features of biofilm.}, journal = {Environmental technology}, volume = {43}, number = {16}, pages = {2443-2456}, doi = {10.1080/09593330.2021.1882583}, pmid = {33502955}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; *Nitrogen/metabolism ; Sewage ; Waste Disposal, Fluid ; }, abstract = {This research aimed the performance evaluation of a structured bed reactor with different cycles of Intermittent Aeration (IA)(SBRRIA) in the municipal sewage treatment and the verification of the effect of IA cycles on the total nitrogen (TN) removal and organic matter (COD). Three IA cycles were evaluated: phase I (4 h AE (aeration on) - 2 h NA (aeration off)); II (2 h AE-1 h NA) and III (2 h AE-2 h NA), with Hydraulic Retention Time of 16 h. The best nitrogen removal was obtained during phase II, with the lowest non-aeration time: efficiency of nitrification, denitrification, TN and COD removal of 80 ± 15%, 82 ± 12%, 67 ± 6% and 94 ± 7%, respectively. The mean cell residence time was 19, 26 and 33 d in phases I, II and III, respectively. The statistical analysis applied to the AE/NA profiles showed that the time of AE and NA in the cycles did not influence nitrogen and organic matter removal. Thus, this indicates the recirculation and the gradient formed in the support material facilitate the process of Simultaneous Nitrification and Denitrification. The lowest concentration of nitrifying and denitrifying microorganisms was obtained in effluent and sludge at the end of phase III. From the TP (Total Proteins)/TPS (Total Polysaccharides) ratio obtained (0.8 ± 0.1, 1.3 ± 0.1 e 1.5 ± 0.1 in phases I, II and III), it was possible to conclude that the biofilm in phase I was more porous, with a thin layer if compared to that in phase II and III.}, } @article {pmid33502310, year = {2021}, author = {Young, EC and Baumgartner, JT and Karatan, E and Kuhn, ML}, title = {A mutagenic screen reveals NspS residues important for regulation of Vibrio cholerae biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {167}, number = {3}, pages = {}, pmid = {33502310}, issn = {1465-2080}, support = {R15 AI096358/AI/NIAID NIH HHS/United States ; R35 GM133506/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Bacterial Proteins/chemistry/*genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Mutagenesis ; Periplasm/genetics/metabolism ; Protein Domains ; Sequence Alignment ; Signal Transduction ; Vibrio cholerae/chemistry/*genetics/physiology ; }, abstract = {Biofilm formation in the human intestinal pathogen Vibrio cholerae is in part regulated by norspermidine, spermidine and spermine. V. cholerae senses these polyamines through a signalling pathway consisting of the periplasmic protein, NspS, and the integral membrane c-di-GMP phosphodiesterase MbaA. NspS and MbaA belong to a proposed class of novel signalling systems composed of periplasmic ligand-binding proteins and membrane-bound c-di-GMP phosphodiesterases containing both GGDEF and EAL domains. In this signal transduction pathway, NspS is hypothesized to interact with MbaA in the periplasm to regulate its phosphodiesterase activity. Polyamine binding to NspS likely alters this interaction, leading to the activation or inhibition of biofilm formation depending on the polyamine. The purpose of this study was to determine the amino acids important for NspS function. We performed random mutagenesis of the nspS gene, identified mutant clones deficient in biofilm formation, determined their responsiveness to norspermidine and mapped the location of these residues onto NspS homology models. Single mutants clustered on two lobes of the NspS model, but the majority were found on a single lobe that appeared to be more mobile upon norspermidine binding. We also identified residues in the putative ligand-binding site that may be important for norspermidine binding and interactions with MbaA. Ultimately, our results provide new insights into this novel signalling pathway in V. cholerae and highlight differences between periplasmic binding proteins involved in transport versus signal transduction.}, } @article {pmid33499213, year = {2021}, author = {Cho, E and Park, Y and Kim, KY and Han, D and Kim, HS and Kwon, JS and Ahn, HJ}, title = {Clinical Characteristics and Relevance of Oral Candida Biofilm in Tongue Smears.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {2}, pages = {}, pmid = {33499213}, issn = {2309-608X}, support = {NRF-2016R1A5A2008630//National Research Foundation of Korea/ ; NRF-2017R1C1B1012464//National Research Foundation of Korea/ ; NRF-2019R1A2C1003028//National Research Foundation of Korea/ ; }, abstract = {Dimorphic Candida exist as commensal yeast carriages or infiltrate hyphae in the oral cavity. Here, we investigated the clinical relevance of Candida hyphae in non-pseudomembranous oral candidiasis (OC) by smears of tongue biofilms. We conducted a retrospective study of 2829 patients who had had tongue smears regardless of OC suspicion. Clinical characteristics were evaluated using a novel method of assessing hyphae. Clinical factors (moderate/severe stimulated pain, pain aggravated by stimulation, tongue dorsum appearance and initial topical antifungal use) were highly significant in the high-grade hyphae group but were statistically similar in the low-grade hyphae and non-observed hyphae group, suggesting low-grade hyphae infection as a subclinical OC state. In addition to erythematous candidiasis (EC), a new subtype named "morphologically normal symptomatic candidiasis" (MNSC) with specific pain patterns and normal tongue morphology was identified. MNSC had a significantly higher proportion of moderate and severe stimulated pain cases than EC. Low unstimulated salivary flow rate (<0.1 mL/min) was found to be a common risk factor in MNSC and EC. In non-pseudomembranous OC, pain patterns were dependent on Candida hyphae degree regardless of tongue dorsum morphology. Morphologic differences seen in high-grade hyphae infection were not associated with systemic diseases or nutritional deficiencies.}, } @article {pmid33496925, year = {2021}, author = {Lahiri, D and Nag, M and Dutta, B and Mukherjee, I and Ghosh, S and Dey, A and Banerjee, R and Ray, RR}, title = {Catechin as the Most Efficient Bioactive Compound from Azadirachta indica with Antibiofilm and Anti-quorum Sensing Activities Against Dental Biofilm: an In Vitro and In Silico Study.}, journal = {Applied biochemistry and biotechnology}, volume = {193}, number = {6}, pages = {1617-1630}, pmid = {33496925}, issn = {1559-0291}, mesh = {Alcaligenes faecalis/*physiology ; Azadirachta/*chemistry ; Biofilms/*drug effects/growth & development ; *Catechin/chemistry/pharmacology ; Computer Simulation ; Plant Leaves/*chemistry ; Porphyromonas gingivalis/*physiology ; }, abstract = {Neem (Azadirachta indica [AI]) is a unique and traditional source of antioxidant and antibacterial compounds. The GC-MS studies revealed that phytoextract of Azadirachta indica comprises a large number of phytocompounds that possess the efficacy of inhibiting the biofilm. It was observed that phytocompounds like catechin showed maximum eradication of biofilm along with the degradation of EPS structural components like carbohydrates and proteins compared to quercetin, nimbolide, nimbin, and azardirachtin, and hence, catechin was proved to be the best against dental plaque-forming bacteria. It was also observed that catechin was able to bring about a marked reduction in quorum sensing (QS) both in Alcaligenes faecalis and Pseudomonas gingivalis dental biofilm-forming strains. The extent of such reduction was maximum for catechin (94.56±2.56% in P. gingivalis & 96.56±2.5 in A. faecalis) in comparison to other bioactive compounds. It was further observed that the bioactive compounds possess the ability to quickly pass across the membrane and bring about inhibition in the DNA and RNA content of the sessile cells. This was further validated by microscopic and in silico studies. Thus, this study revealed that catechin obtained from the phytoextract of AI showed a marked ability to inhibit the dental biofilm and can be used as a natural drug-like compound in treating biofilm-associated chronic infections.}, } @article {pmid33496815, year = {2021}, author = {Xu, C and Wang, F and Huang, F and Yang, M and He, D and Deng, L}, title = {Targeting effect of berberine on type I fimbriae of Salmonella Typhimurium and its effective inhibition of biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {4}, pages = {1563-1573}, pmid = {33496815}, issn = {1432-0614}, support = {31770109//National Natural Science Foundation of China/ ; 21775036//National Natural Science Foundation of China/ ; }, mesh = {*Berberine/pharmacology ; Biofilms ; Fimbriae Proteins/genetics ; Fimbriae, Bacterial/genetics ; Humans ; *Salmonella typhimurium/genetics ; }, abstract = {As a primary cause of food contamination and human diseases, Salmonella Typhimurium can easily form a biofilm that is difficult to remove from food surfaces, and often causes significant invisible threats to food safety. Although berberine has been widely used as an anti-infective drug in traditional medicine, some basic principles underlying its mechanism, especially the interaction between berberine and type I fimbriae genes, has not been verified yet. In this study, two strains of major fimbrial gene mutants (ΔfimA and ΔfimH) were constructed to demonstrate the possible action of berberine on type I fimbriae genes. The broth microdilution method was used to determine the antibacterial activity of berberine against selected strains (WT, ΔfimA, and ΔfimH). Cell agglutination experiments revealed that the number of S. Typhimurium type I fimbriae reduced after berberine treatment, which was consistent with transmission electron microscopy results. Quantitative real-time PCR experiments also confirmed that berberine reduced fimA gene expression, indicating a certain interaction between berberine and fimA gene. Furthermore, confocal laser scanning microscopy imaging of biofilm clearly revealed that berberine prevents biofilm formation by reducing the number of type I fimbriae. Overall, it is well speculated for us that berberine could be an excellent combating-biofilm drug in clinical microbiology and food preservation. KEY POINTS: • Reduce the number of fimbriae. • Berberine targeting fimA. • Effective biofilm inhibitor.}, } @article {pmid33496680, year = {2021}, author = {Bielik, B and Molnár, L and Vrabec, V and Andrášiová, R and Maruščáková, IC and Nemcová, R and Toporčák, J and Mudroňová, D}, title = {Biofilm-forming lactic acid bacteria of honey bee origin intended for potential probiotic use.}, journal = {Acta veterinaria Hungarica}, volume = {68}, number = {4}, pages = {345-353}, doi = {10.1556/004.2020.00057}, pmid = {33496680}, issn = {0236-6290}, mesh = {Animals ; Bees ; Biofilms ; Enterococcaceae ; *Lactobacillales ; Pilot Projects ; *Probiotics ; United States ; }, abstract = {Scientists around the world are focusing their interest on the use of probiotics in honey bees as an alternative method of prophylaxis against causative agents of both American and European foulbrood. In our study we tested inhibitory activity against Paenibacillus larvae and the biofilm formation activity by various lactic acid bacteria isolated from honey bee guts or fresh pollen samples in the presence of different sugars added to the cultivation media. In addition, we tested the probiotic effect of a newly selected Apilactobacillus kunkeei V18 in an in situ experiment in bee colonies. We found antibacterial activity against P. larvae in four isolates. Biofilm formation activity of varying intensity was noted in six of the seven isolates in the presence of different sugars. The strongest biofilm formation (OD570 ≥ 1) was noted in A. kunkeei V18 in the presence of fructose; moreover, this isolate strongly inhibited the growth of P. larvae under laboratory conditions. Inhibition of P. larvae and Melissococcus plutonius by A. kunkeei V18 in situ was confirmed in a pilot study.}, } @article {pmid33495449, year = {2021}, author = {Wu, BC and Haney, EF and Akhoundsadegh, N and Pletzer, D and Trimble, MJ and Adriaans, AE and Nibbering, PH and Hancock, REW}, title = {Human organoid biofilm model for assessing antibiofilm activity of novel agents.}, journal = {NPJ biofilms and microbiomes}, volume = {7}, number = {1}, pages = {8}, pmid = {33495449}, issn = {2055-5008}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Anti-Inflammatory Agents/pharmacology/therapeutic use ; Bacterial Load/drug effects ; Biofilms/*drug effects/growth & development ; Burns/drug therapy/immunology/microbiology ; Drug Evaluation, Preclinical ; Drug Therapy, Combination ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; *Models, Biological ; Oligopeptides/pharmacology/therapeutic use ; Organoids/drug effects/immunology/injuries/*microbiology ; Pseudomonas aeruginosa/drug effects ; Skin/drug effects/immunology/injuries/microbiology ; }, abstract = {Bacterial biofilms cause 65% of all human infections and are highly resistant to antibiotic therapy but lack specific treatments. To provide a human organoid model for studying host-microbe interplay and enabling screening for novel antibiofilm agents, a human epidermis organoid model with robust methicillin-resistant Staphylococcus aureus (MRSA) USA300 and Pseudomonas aeruginosa PAO1 biofilm was developed. Treatment of 1-day and 3-day MRSA and PAO1 biofilms with antibiofilm peptide DJK-5 significantly and substantially reduced the bacterial burden. This model enabled the screening of synthetic host defense peptides, revealing their superior antibiofilm activity against MRSA compared to the antibiotic mupirocin. The model was extended to evaluate thermally wounded skin infected with MRSA biofilms resulting in increased bacterial load, cytotoxicity, and pro-inflammatory cytokine levels that were all reduced upon treatment with DJK-5. Combination treatment of DJK-5 with an anti-inflammatory peptide, 1002, further reduced cytotoxicity and skin inflammation.}, } @article {pmid33495249, year = {2021}, author = {López-Martín, M and Dubern, JF and Alexander, MR and Williams, P}, title = {AbaM Regulates Quorum Sensing, Biofilm Formation, and Virulence in Acinetobacter baumannii.}, journal = {Journal of bacteriology}, volume = {203}, number = {8}, pages = {}, pmid = {33495249}, issn = {1098-5530}, support = {103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; 103882/WT_/Wellcome Trust/United Kingdom ; }, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/genetics/*pathogenicity/physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Humans ; *Quorum Sensing ; Virulence ; }, abstract = {Acinetobacter baumannii possesses a single divergent luxR/luxRI-type quorum-sensing (QS) locus named abaR/abaI This locus also contains a third gene located between abaR and abaI, which we term abaM, that codes for an uncharacterized member of the RsaM protein family known to regulate N-acylhomoserine lactone (AHL)-dependent QS in other beta- and gammaproteobacteria. Here, we show that disruption of abaM via a T26 insertion in A. baumannii strain AB5075 resulted in increased production of N-(3-hydroxydodecanoyl)-l-homoserine lactone and enhanced surface motility and biofilm formation. In contrast to the wild type and the abaI::T26 mutant, the virulence of the abaM::T26 mutant was completely attenuated in a Galleria mellonella infection model. Transcriptomic analysis of the abaM::T26 mutant revealed that AbaM differentially regulates at least 76 genes, including the csu pilus operon and the acinetin 505 lipopeptide biosynthetic operon, that are involved in surface adherence, biofilm formation and virulence. A comparison of the wild type, abaM::T26 and abaI::T26 transcriptomes, indicates that AbaM regulates ∼21% of the QS regulon including the csu operon. Moreover, the QS genes (abaI and abaR) were among the most upregulated in the abaM::T26 mutant. A. baumanniilux-based abaM reporter gene fusions revealed that abaM expression is positively regulated by QS but negatively autoregulated. Overall, the data presented in this work demonstrates that AbaM plays a central role in regulating A. baumannii QS, virulence, surface motility, and biofilm formation.IMPORTANCEAcinetobacter baumannii is a multiantibiotic-resistant pathogen of global health care importance. Understanding Acinetobacter virulence gene regulation could aid the development of novel anti-infective strategies. In A. baumannii, the abaR and abaI genes that code for the receptor and synthase components of an N-acylhomoserine (AHL) lactone-dependent quorum sensing system (QS) are separated by abaM Here, we show that although mutation of abaM increased AHL production, surface motility, and biofilm development, it resulted in the attenuation of virulence. AbaM was found to control both QS-dependent and QS-independent genes. The significance of this work lies in the identification of AbaM, an RsaM ortholog known to control virulence in plant pathogens, as a modulator of virulence in a human pathogen.}, } @article {pmid33494900, year = {2021}, author = {Bansal, M and Dhowlaghar, N and Nannapaneni, R and Kode, D and Chang, S and Sharma, CS and McDaniel, C and Kiess, A}, title = {Decreased biofilm formation by planktonic cells of Listeria monocytogenes in the presence of sodium hypochlorite.}, journal = {Food microbiology}, volume = {96}, number = {}, pages = {103714}, doi = {10.1016/j.fm.2020.103714}, pmid = {33494900}, issn = {1095-9998}, mesh = {Biofilms/*drug effects ; Disinfectants/*pharmacology ; Listeria monocytogenes/*drug effects/growth & development ; Plankton/drug effects/growth & development ; Sodium Hypochlorite/*pharmacology ; }, abstract = {The objective of this study was to determine if the adaptation at planktonic stage to subinhibitory concentrations (SIC) of sodium hypochlorite (NaOCl) could modulate the biofilm forming ability of five Listeria monocytogenes strains V7, Scott A, FSL-N1-227, FSL F6-154 and ATCC 19116 representing serotypes 1/2a, 4b and 4c. Biofilm formation by NaOCl nonadapted and adapted L. monocytogenes planktonic cells was measured in the presence or absence of SIC of NaOCl. The biofilm formation ability of NaOCl nonadapted and adapted L. monocyotgenes planktonic cells was reduced only in the presence of NaOCl (P < 0.05). Scanning electron microscopy revealed that the continuous exposure of NaOCl induced morphological changes in the L. monocytogenes biofilm structure and reduced its attachment to polystyrene surface. The qRT-PCR results also showed that the subinhibitory NaOCl reduced biofilm formation related gene expression such as motility and quorum sensing signals (P < 0.05). These findings indicate that subinhibitory NaOCl can reduce the ability of L. monocytogenes planktonic cells to form biofilms on polystyrene surface.}, } @article {pmid33494399, year = {2021}, author = {Gerner, E and Almqvist, S and Thomsen, P and Werthén, M and Trobos, M}, title = {Sodium Salicylate Influences the Pseudomonas aeruginosa Biofilm Structure and Susceptibility Towards Silver.}, journal = {International journal of molecular sciences}, volume = {22}, number = {3}, pages = {}, pmid = {33494399}, issn = {1422-0067}, support = {ID16-0036//Stiftelsen för Strategisk Forskning/ ; No 754412//H2020 Marie Skłodowska-Curie Actions/ ; 2018-02891//Vetenskapsrådet/ ; ALFGBG-725641//ALF/ ; 2017-373//Dr Felix Neubergh/ ; 2019/86//Adlerbertska Foundation/ ; HJSV2020081//Handlanden Hjalmar Svensson/ ; -//Centre for Antibiotic Resistance Research at University of Gothenburg/ ; -//the Swedish state under the agreement between the Swedish government and the county councils/ ; -//the IngaBritt and Arne Lundberg Foundation/ ; -//the Area of Advance Materials of Chalmers and GU Biomaterials within the Strategic Research Area initiative launched by the Swedish government/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/*growth & development ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Quorum Sensing/drug effects ; Silver/*pharmacology ; Sodium Salicylate/*pharmacology ; Virulence Factors ; }, abstract = {Hard-to-heal wounds are typically infected with biofilm-producing microorganisms, such as Pseudomonas aeruginosa, which strongly contribute to delayed healing. Due to the global challenge of antimicrobial resistance, alternative treatment strategies are needed. Here, we investigated whether inhibition of quorum sensing (QS) by sodium salicylate in different P. aeruginosa strains (QS-competent, QS-mutant, and chronic wound strains) influences biofilm formation and tolerance to silver. Biofilm formation was evaluated in simulated serum-containing wound fluid in the presence or absence of sodium salicylate (NaSa). Biofilms were established using a 3D collagen-based biofilm model, collagen coated glass, and the Calgary biofilm device. Furthermore, the susceptibility of 48-h-old biofilms formed by laboratory and clinical strains in the presence or absence of NaSa towards silver was evaluated by assessing cell viability. Biofilms formed in the presence of NaSa were more susceptible to silver and contained reduced levels of virulence factors associated with biofilm development than those formed in the absence of NaSa. Biofilm aggregates formed by the wild-type but not the QS mutant strain, were smaller and less heterogenous in size when grown in cultures with NaSa compared to control. These data suggest that NaSa, via a reduction of cell aggregation in biofilms, allows the antiseptic to become more readily available to cells.}, } @article {pmid33494273, year = {2021}, author = {Shinde, S and Lee, LH and Chu, T}, title = {Inhibition of Biofilm Formation by the Synergistic Action of EGCG-S and Antibiotics.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {2}, pages = {}, pmid = {33494273}, issn = {2079-6382}, abstract = {Biofilm, a stress-induced physiological state, is an established means of antimicrobial tolerance. A perpetual increase in multidrug resistant (MDR) infections associated with high mortality and morbidity have been observed in healthcare settings. Multiple studies have indicated that the use of natural products can prevent bacterial growth. Recent studies in the field have identified that epigallocatechin gallate (EGCG), a green tea polyphenol, could disrupt bacterial biofilms. A modified lipid-soluble EGCG, epigallocatechin-3-gallate-stearate (EGCG-S), has enhanced the beneficial properties of green tea. This study focuses on utilizing EGCG-S as a novel synergistic agent with antibiotics to prevent or control biofilm. Different formulations of EGCG-S and selected antibiotics were used to study their combinatorial effects on biofilms produced by five potential pathogenic bacteria, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Mycobacterium smegmatis. The crystal violet (CV) assay and the sensitive fluorescence-based resazurin biofilm viability assay were used to assess the biofilm production. Our results identified optimal formulation for each bacterium, effectively inhibiting biofilm formation to an extent of 95-99%. Colony-forming unit (CFU) and cell viability analyses showed a decrease of viable bacteria. These results depict the potential of EGCG-S as a synergistic agent with antibiotics and as an anti-biofilm agent.}, } @article {pmid33492206, year = {2021}, author = {Skovdal, SM and Hansen, LK and Ivarsen, DM and Zeng, G and Büttner, H and Rohde, H and Jørgensen, NP and Meyer, RL}, title = {Host factors abolish the need for polysaccharides and extracellular matrix-binding protein in Staphylococcus epidermidis biofilm formation.}, journal = {Journal of medical microbiology}, volume = {70}, number = {3}, pages = {}, pmid = {33492206}, issn = {1473-5644}, mesh = {Adhesins, Bacterial/*metabolism ; Bacterial Adhesion ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Humans ; Polysaccharides, Bacterial/*metabolism ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/*physiology ; }, abstract = {Introduction. Staphylococcus epidermidis is predominant in implant-associated infections due to its capability to form biofilms. It can deploy several strategies for biofilm development using either polysaccharide intercellular adhesin (PIA), extracellular DNA (eDNA) and/or proteins, such as the extracellular matrix-binding protein (Embp).Hypothesis/Gap Statement. We hypothesize that the dichotomic regulation of S. epidermidis adhesins is linked to whether it is inside a host or not, and that in vitro biofilm investigations in laboratory media may not reflect actual biofilms in vivo.Aim. We address the importance of PIA and Embp in biofilm grown in 'humanized' media to understand if these components play different roles in biofilm formation under conditions where bacteria can incorporate host proteins in the biofilm matrix.Methodology. S. epidermidis 1585 WT (deficient in icaADBC), and derivative strains that either lack embp, express embp from an inducible promotor, or express icaADBC from a plasmid, were cultivated in standard laboratory media, or in media with human plasma or serum. The amount, structure, elasticity and antimicrobial penetration of biofilms was quantified to describe structural differences caused by the different matrix components and growth conditions. Finally, we quantified the initiation of biofilms as suspended aggregates in response to host factors to determine how quickly the cells aggregate in response to the host environment and reach a size that protects them from phagocytosis.Results. S. epidermidis 1585 required polysaccharides to form biofilm in laboratory media. However, these observations were not representative of the biofilm phenotype in the presence of human plasma. If human plasma were present, polysaccharides and Embp were redundant for biofilm formation. Biofilms formed in human plasma were loosely attached and existed mostly as suspended aggregates. Aggregation occurred after 2 h of exposing cells to plasma or serum. Despite stark differences in the amount and composition of biofilms formed by polysaccharide-producing and Embp-producing strains in different media, there were no differences in vancomycin penetration or susceptibility.Conclusion. We suggest that the assumed importance of polysaccharides for biofilm formation is an artefact from studying biofilms in laboratory media void of human matrix components. The cell-cell aggregation of S. epidermidis can be activated by host factors without relying on either of the major adhesins, PIA and Embp, indicating a need to revisit the basic question of how S. epidermidis deploys self-produced and host-derived matrix components to form antibiotic-tolerant biofilms in vivo.}, } @article {pmid33491458, year = {2021}, author = {Purdy, GE and Hsu, FF}, title = {Complete Characterization of Polyacyltrehaloses from Mycobacterium tuberculosis H37Rv Biofilm Cultures by Multiple-Stage Linear Ion-Trap Mass Spectrometry Reveals a New Tetraacyltrehalose Family.}, journal = {Biochemistry}, volume = {60}, number = {5}, pages = {381-397}, pmid = {33491458}, issn = {1520-4995}, support = {R21 AI144658/AI/NIAID NIH HHS/United States ; R35 GM128562/GM/NIGMS NIH HHS/United States ; P30 DK056341/DK/NIDDK NIH HHS/United States ; P41 GM103422/GM/NIGMS NIH HHS/United States ; P30 DK020579/DK/NIDDK NIH HHS/United States ; R24 GM136766/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; Cell Wall/chemistry ; Fatty Acids/chemistry ; Gas Chromatography-Mass Spectrometry/methods ; Glycolipids/chemistry ; Mycobacterium tuberculosis/*chemistry/*enzymology/metabolism ; Protein Isoforms/chemistry ; Spectrometry, Mass, Electrospray Ionization/methods ; Trehalose/*chemistry/metabolism ; }, abstract = {Polyacylated trehaloses in Mycobacterium tuberculosis play important roles in pathogenesis and structural roles in the cell envelope, promoting the intracellular survival of the bacterium, and are potential targets for drug development. Herein, we describe a linear ion-trap multiple-stage mass spectrometric approach (LIT MS[n]) with high-resolution mass spectrometry to the structural characterization of a glycolipid family that includes a 2,3-diacyltrehalose, 2,3,6-triacyltrehalose, 2,3,6,2',4'-petaacyltrehalose, and a novel 2,3,6,2'-tetraacyltrehalose (TetraAT) subfamily isolated from biofilm cultures of M. tuberculosis H37Rv. The LIT MS[n] spectra (n = 2, 3, or 4) provide structural information to unveil the location of the palmitoyl/stearoyl and one to four multiple methyl-branched fatty acyl substituents attached to the trehalose backbone, leading to the identification of hundreds of glycolipid species with many isomeric structures. We identified a new TetraAT subfamily whose structure has not been previously defined. We also developed a strategy for defining the structures of the multiple methyl-branched fatty acid substituents, leading to the identification of mycosanoic acid, mycolipenic acid, mycolipodienoic acid, mycolipanolic acid, and a new cyclopropyl-containing acid. The observation of the new TetraAT family, and the realization of the structural similarity between the various subfamilies, may have significant implications in the biosynthetic pathways of this glycolipid family.}, } @article {pmid33491383, year = {2021}, author = {Abdul Aziz, A and Gonzalez, MAG and Yap, AU}, title = {Impact of early biofilm on the assessment of initial enamel erosion with swept-source optical coherence tomography.}, journal = {Quintessence international (Berlin, Germany : 1985)}, volume = {0}, number = {0}, pages = {476-486}, doi = {10.3290/j.qi.b912625}, pmid = {33491383}, issn = {1936-7163}, mesh = {Actinomyces ; Biofilms ; Dental Enamel/diagnostic imaging ; Humans ; Tomography, Optical Coherence ; *Tooth Demineralization/diagnostic imaging ; *Tooth Erosion/diagnostic imaging ; }, abstract = {Objective: This study examined the impact of early biofilm on the tooth surface, during the assessment of initial enamel erosion using swept-source optical coherence tomography (SS-OCT). Method and materials: Forty-five enamel windows of 2 × 4 mm2 were prepared on 23 extracted human teeth. The specimens were exposed to citric acid (pH 3.2) for 30 minutes and randomly divided into three groups (n = 15): Group 1, no biofilm; Group 2, 1-day-old biofilm; and Group 3, 3-day-old biofilm. Specimens in Groups 2 and 3 were inoculated with oral bacteria (Streptococcus sanguinis, Streptococcus mitis, and Actinomyces naeslundii) to produce early laboratory-cultivated biofilms for 1 and 3 days respectively. Surface microhardness (SMH) measurements were taken at pre- (t1) and post-erosion (t2); and SS-OCT scans were done at t1, t2, and post-biofilm cultivation (t3). Integrated reflectivity (IR) of the tooth-air interface (IRsurface) and enamel (IRenamel) were computed from the mean A-scans. Statistical analysis was performed using paired t tests and one-way ANOVA (α = .05). Results: A significant increase in IRenamel was observed at t2 (P < .05). At t3, IRsurface between Group 1 (control) and Group 2 (P = .012) as well as Group 3 (P = .001) were significantly different. Significant variances in IRenamel were perceived between t2 and t3 for Groups 2 and 3 but not for Group 1. Conclusion: As early biofilm affected SS-OCT assessment of initial enamel erosion, they should be removed from the tooth surface prior to OCT procedures..}, } @article {pmid33491375, year = {2021}, author = {Jentsch, H and Rodloff, AC and Gerweck, MK and Stingu, CS}, title = {Streptococci in the Subgingival Biofilm and Periodontal Therapy.}, journal = {Oral health & preventive dentistry}, volume = {19}, number = {1}, pages = {25-31}, doi = {10.3290/j.ohpd.b875517}, pmid = {33491375}, issn = {1757-9996}, mesh = {Biofilms ; *Dental Scaling ; Humans ; *Periodontitis ; Root Planing ; Streptococcus oralis ; }, abstract = {Purpose: The aim of this study was to verify how the prevalence of viridans-streptococci is changed by two appointments of professional prophylaxis and after the subgingival instrumentation via scaling and root planing (SRP). Material and Methods: Samples of the subgingival biofilm were collected from 19 individuals with periodontitis receiving two appointments of professional prophylaxis and SRP before and after the treatment procedures and the presence of viridans-streptococci was analysed by microbiological cultivation. Non-parametric statistical testing using Friedman/Wilcoxon tests and chi-square testing was used for statistical analysis. Results: No statistically significant changes over time were found for the mutans-group. The prevalence of Streptococcus mitis decreased after two appointments of professional prophylaxis (p = 0.013). The prevalence of S. mitis decreased again after SRP (p <0.001). The prevalence of Streptococcus anginosus decreased after two appointments of professional prophylaxis (p = 0.002). After SRP five positive results for S. anginosus were detected (p = 0.026). For Streptococcus oralis and Streptococcus gordonii tendencies to statistical significance were found. The number of positive results for S. oralis increased after the first appointment of professional oral prophylaxis (p = 0.055). The number of positive results for S. gordonii increased after the first appointment of professional oral prophylaxis (p = 0.055). Conclusion: The step-wise periodontal therapy influences the prevalence of viridans-streptococci, especially S. mitis and S. anginosus. No tremendous increase of streptococci especially related to the carious process occurs in the subgingival biofilm. Clinical Relevance: The study reveals knowledge on changes of the composition of the subgingival biofilm due to different steps of periodontal therapy.}, } @article {pmid33490870, year = {2020}, author = {Newton, R and Amstutz, J and Patrick, JE}, title = {Biofilm formation by Bacillus subtilis is altered in the presence of pesticides.}, journal = {Access microbiology}, volume = {2}, number = {12}, pages = {acmi000175}, pmid = {33490870}, issn = {2516-8290}, abstract = {Bacillus subtilis uses swarming motility and biofilm formation to colonize plant roots and form a symbiotic relationship with the plant. Swarming motility and biofilm formation are group behaviours made possible through the use of chemical messengers. We investigated whether chemicals applied to plants would interfere with the swarming motility and biofilm-forming capabilities of B. subtilis in vitro. We hypothesized that pesticides could act as chemical signals that influence bacterial behaviour; this research investigates whether swarming motility and biofilm formation of B. subtilis is affected by the application of the commercial pesticides with the active ingredients of neem oil, pyrethrin, or malathion. The results indicate that all three pesticides inhibit biofilm formation. Swarming motility is not affected by the application of pyrethrin or malathion, but swarm expansion and pattern is altered in the presence of neem oil. Future studies to investigate the mechanism by which pesticides alter biofilm formation are warranted.}, } @article {pmid33490768, year = {2021}, author = {Li, H and Han, X and Dong, Y and Xu, S and Chen, C and Feng, Y and Cui, Q and Li, W}, title = {Bacillaenes: Decomposition Trigger Point and Biofilm Enhancement in Bacillus.}, journal = {ACS omega}, volume = {6}, number = {2}, pages = {1093-1098}, pmid = {33490768}, issn = {2470-1343}, abstract = {Bacillaenes are a class of poly-unsaturated enamines produced by Bacillus strains that are notoriously unstable toward light, oxygen, and normal temperature. Herein, in an in-depth study of this highly unstable chemotype, the stability and biological function of bacillaenes were investigated. The structure change of the bacillaene scaffold was tracked by time-course [1]H NMR data analysis coupled with the differential analysis of 2D-NMR spectra method, which was demonstrated to be a "domino" effect triggered by 4',5'-cis (2 and 3) configuration rearranged to trans (2a and 3a). These findings provide the possibility for stabilizing the bacillaene scaffold by chemical modification of its trigger points. In the biofilm assay, compounds 1 and 2 accelerated self-biofilm formation in Bacillus methylotrophicus B-9987 at low concentrations of 1.0 and 0.1 μg/mL. Interestingly, bacillaenes play dual roles as antibiotic and biofilm enhancers in a dose-dependent manner, both of which serve in the self-protection of Bacillus.}, } @article {pmid33490247, year = {2020}, author = {Rafiee, A and Memarpour, M and Najibi, Y and Khalvati, B and Kianpour, S and Morowvat, MH}, title = {Antimicrobial Efficacy of a Novel Antibiotic-Eluting Injectable Platelet-Rich Fibrin Scaffold against a Dual-Species Biofilm in an Infected Immature Root Canal Model.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {6623830}, pmid = {33490247}, issn = {2314-6141}, mesh = {Actinomyces/drug effects ; Anti-Bacterial Agents/*pharmacology ; Bicuspid/microbiology/surgery ; Biofilms/*drug effects ; *Dental Pulp Cavity/drug effects/microbiology ; Enterococcus faecalis/drug effects ; Humans ; *Platelet-Rich Fibrin ; *Root Canal Therapy ; }, abstract = {BACKGROUND AND AIMS: This study was aimed at evaluating the antibacterial property of an injectable platelet-rich fibrin (I-PRF) scaffold containing triple antibiotic mixture against an Actinomyces naeslundii (A. naeslundii) and Enterococcus faecalis (E. faecalis) biofilm in an infected immature root canal model.

METHODS: A dual-species biofilm was inoculated inside the root canals via a series of centrifugal cycles. The samples were allocated to three experimental groups (i.e., G1: triple antibiotic mixture, G2: I-PRF containing triple antibiotic mixture, and G3: antibiotic-free I-PRF scaffold) and two control groups (G4: seven-day biofilm untreated and G5: bacteria-free untreated).

RESULTS: Bacterial gene quantification change and the overall reduction of live bacteria were evaluated. The highest antibacterial activity against A. naeslundii belonged to G2. However, G1 and G2 had similar antibacterial property against E. faecalis (p value = 0.814). In general, experimental groups revealed higher levels of antibacterial activity against E. faecalis than against A. naeslundii (p value < 0.001). Notably, G2 could dramatically decrease the number of live bacteria up to near 92%.

CONCLUSIONS: The current study provides insight into the antibacterial property of an antibiotic-eluting I-PRF scaffold against a dual-species biofilm colonized inside the root canal. The fabricated scaffold contains not only the antibiotics but also the growth factors, which favor the regeneration.}, } @article {pmid33489419, year = {2021}, author = {Nguyen, TH and Nguyen, MK and Le, THO and Bui, TT and Nguyen, TH and Nguyen, TQ and van Ngo, A}, title = {Kinetics of Organic Biodegradation and Biogas Production in the Pilot-Scale Moving Bed Biofilm Reactor (MBBR) for Piggery Wastewater Treatment.}, journal = {Journal of analytical methods in chemistry}, volume = {2021}, number = {}, pages = {6641796}, pmid = {33489419}, issn = {2090-8865}, abstract = {In this research, the kinetics of COD biodegradation and biogas production in a moving bed biofilm reactor (MBBR) at pilot scale (10 m[3]) for piggery wastewater treatment were investigated. Polyethylene (PE) was used as a carrying material, with organic loading rates (OLRs) of 10, 15, and 18 kgCOD/m[3] day in accordance to hydraulic retention times (HRTs) of 0.56, 0.37, and 0.3 day. The results showed that a high COD removal efficiency was obtained in the range of 68-78% with the influent COD of 5.2-5.8 g/L at all 3 HRTs. About COD degradation kinetics, in comparison to the first- and second-order kinetics and the Monod model, Stover-Kincannon model showed the best fit with R [2] 0.98 and a saturation value constant (K B) and a maximum utilization rate (U max) of 52.40 g/L day and 82.65 g/L day, respectively. The first- and second-order kinetics with all 3 HRTs and Monod model with the HRT of 0.56 day also obtained high R [2] values. Therefore, these kinetics and models can be further considered to be used for predicting the kinetic characteristics of the MBBR system in piggery wastewater treatment process. The result of a 6-month operation of the MBBR was that biogas production was mostly in the operating period of days 17 to 80, around 0.2 to 0.3 and 0.15-0.20 L/gCODconverted, respectively, and then reduction at an OLR of 18 kgCOD/m[3]. After the start-up stage, day 35 biogas cumulative volume fluctuated from 20 to 30 m[3]/day and reached approximately 3500 m[3] for 178 days during the whole digestive process. Methane is accounted for about 65-70% of biogas with concentration around 400 mg/L.}, } @article {pmid33489239, year = {2021}, author = {Hashemzadeh, M and Dezfuli, AAZ and Nashibi, R and Jahangirimehr, F and Akbarian, ZA}, title = {Study of biofilm formation, structure and antibiotic resistance in Staphylococcus saprophyticus strains causing urinary tract infection in women in Ahvaz, Iran.}, journal = {New microbes and new infections}, volume = {39}, number = {}, pages = {100831}, pmid = {33489239}, issn = {2052-2975}, abstract = {Staphylococcus saprophyticus is the second most frequent community-acquired causative agent of acute urinary tract infection (UTI). Some strains of S. saprophyticus can create biofilms, increasing their virulence. Once biofilms have been produced, antibiotic resistance is exacerbated. Hence, the aims of the present study were the study of biofilm formation, structure and antibiotic resistance in S. saprophyticus strains causing UTIs in women in Ahvaz, Iran. Overall, 43 S. saprophyticus isolates were recovered from UTIs. Antibiotic resistance pattern and the biofilm production and structure were determined using phenotypic methods. Most S. saprophyticus isolates were resistant to erythromycin, but all isolates were sensitive to linezolid and vancomycin. Fifty-eight per cent of S. saprophyticus were multidrug resistant. Twenty-one per cent of S. saprophyticus isolates harbored the mecA gene. Biofilm formation was observed in 65% of S. saprophyticus isolates and most had polysaccharide matrix. Our data indicate high rates of antibiotic resistance and the capability of biofilm formation among S. saprophyticus isolates. The emergence of antibiotic resistance in the management of UTIs is a serious public health issue. The findings of this study could be used to improve treatment plans to control UTIs. Consequently, increased awareness of the mechanisms underlying biofilm formation and the development of drug resistance will allow UTIs to be more efficiently controlled and treated.}, } @article {pmid33488963, year = {2021}, author = {Nijampatnam, B and Ahirwar, P and Pukkanasut, P and Womack, H and Casals, L and Zhang, H and Cai, X and Michalek, SM and Wu, H and Velu, SE}, title = {Discovery of Potent Inhibitors of Streptococcus mutans Biofilm with Antivirulence Activity.}, journal = {ACS medicinal chemistry letters}, volume = {12}, number = {1}, pages = {48-55}, pmid = {33488963}, issn = {1948-5875}, support = {R01 DE017954/DE/NIDCR NIH HHS/United States ; R03 DE025058/DE/NIDCR NIH HHS/United States ; R01 DE028329/DE/NIDCR NIH HHS/United States ; R01 DE022350/DE/NIDCR NIH HHS/United States ; R21 DE028349/DE/NIDCR NIH HHS/United States ; F31 DE025783/DE/NIDCR NIH HHS/United States ; }, abstract = {Dental caries is a bacterial infectious disease characterized by demineralization of the tooth enamel. Treatment of this disease with conventional antibiotics is largely ineffective as the cariogenic bacteria form tenacious biofilms that are resistant to such treatments. The main etiological agent for dental caries is the bacterium Streptococcus mutans. S. mutans readily forms biofilms on the tooth surface and rapidly produces lactic acid from dietary sucrose. Glucosyl transferases (Gtfs) secreted by S. mutans are mainly responsible for the production of exopolysaccharides that are crucial for the biofilm architecture. Thus, inhibiting S. mutans' Gtfs is an effective approach to develop selective biofilm inhibitors that do not affect the growth of oral commensals. Herein, we report a library of 90 analogs of the previously identified lead compound, G43, and exploration of its structure activity relationships (SAR). All compounds were evaluated for the inhibition of S. mutans biofilms and bacterial growth. Selected compounds from this library were further evaluated for enzyme inhibition against Gtfs using a zymogram assay and for growth inhibition against oral commensal bacterial species such as Streptococcus gordonii and Streptococcus sanguinis. This study has led to the discovery of several new biofilm inhibitors with enhanced potency and selectivity. One of the leads, III F1 , showed marked reduction in buccal, sulcal, and proximal caries scores in a rat model of dental caries.}, } @article {pmid33488716, year = {2020}, author = {Ghasemi, N and Behnezhad, M and Asgharzadeh, M and Zeinalzadeh, E and Kafil, HS}, title = {Antibacterial Properties of Aloe vera on Intracanal Medicaments against Enterococcus faecalis Biofilm at Different Stages of Development.}, journal = {International journal of dentistry}, volume = {2020}, number = {}, pages = {8855277}, pmid = {33488716}, issn = {1687-8728}, abstract = {BACKGROUND: Use of herbal compounds as an intracanal medicament in the field of endodontics has become noteworthy, one of which is the Aloe vera compound whose antibacterial effect has already been proven in the planktonic form of Enterococcus faecalis. The purpose of this study is to evaluate the antibacterial effect of Aloe vera on E. faecalis biofilms at the 4[th] and 6[th] week of development.

MATERIALS AND METHODS: 130 single root canal teeth without anomalies and caries were used. They were divided into two groups of 65 teeth for four and six weeks of biofilm production. Five samples of each group were examined for confirmation of biofilm formation under an electron microscope. Study groups were investigated with an antimicrobial agent as an intracanal medicament including 20 samples treated with Aloe vera, calcium hydroxide, and phosphate-buffered saline, and biofilm and survival of pathogens were investigated. Dentin chip suspensions were used for colony-forming unit (CFU) counting to estimate remaining E. faecalis counts.

RESULTS: The CFU mean in the 4[th] week subgroup in Aloe vera, phosphate-buffered saline, and calcium hydroxide was 0, 69166.66 ± 31688.58, and 25000 ± 30822.07, and in the 6[th] week, it was 136.36 ± 323.33, 95000 ± 12247.44, and 27501.66 ± 36570.34, respectively, which showed a significant difference between the used materials (p < 0.05).

CONCLUSION: Aloe vera, in contrast to calcium hydroxide, eliminated 4[th] and 6[th] week biofilms and showed remarkable antibacterial properties against E. faecalis biofilm. These results support potency of Aloe vera to use as a natural antimicrobial material in the intracanal medicament.}, } @article {pmid33488556, year = {2020}, author = {Seike, S and Kobayashi, H and Ueda, M and Takahashi, E and Okamoto, K and Yamanaka, H}, title = {Outer Membrane Vesicles Released From Aeromonas Strains Are Involved in the Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {613650}, pmid = {33488556}, issn = {1664-302X}, abstract = {Aeromonas spp. are Gram-negative rod-shaped bacteria ubiquitously distributed in diverse water sources. Several Aeromonas spp. are known as human and fish pathogens. Recently, attention has been focused on the relationship between bacterial biofilm formation and pathogenicity or drug resistance. However, there have been few reports on biofilm formation by Aeromonas. This study is the first to examine the in vitro formation and components of the biofilm of several Aeromonas clinical and environmental strains. A biofilm formation assay using 1% crystal violet on a polystyrene plate revealed that most Aeromonas strains used in this study formed biofilms but one strain did not. Analysis of the basic components contained in the biofilms formed by Aeromonas strains confirmed that they contained polysaccharides containing GlcNAc, extracellular nucleic acids, and proteins, as previously reported for the biofilms of other bacterial species. Among these components, we focused on several proteins fractionated by SDS-PAGE and determined their amino acid sequences. The results showed that some proteins existing in the Aeromonas biofilms have amino acid sequences homologous to functional proteins present in the outer membrane of Gram-negative bacteria. This result suggests that outer membrane components may affect the biofilm formation of Aeromonas strains. It is known that Gram-negative bacteria often release extracellular membrane vesicles from the outer membrane, so we think that the outer membrane-derived proteins found in the Aeromonas biofilms may be derived from such membrane vesicles. To examine this idea, we next investigated the ability of Aeromonas strains to form outer membrane vesicles (OMVs). Electron microscopic analysis revealed that most Aeromonas strains released OMVs outside the cells. Finally, we purified OMVs from several Aeromonas strains and examined their effect on the biofilm formation. We found that the addition of OMVs dose-dependently promoted biofilm formation, except for one strain that did not form biofilms. These results suggest that the OMVs released from the bacterial cells are closely related to the biofilm formation of Aeromonas strains.}, } @article {pmid33488188, year = {2020}, author = {SÜrdem, S and DoĞan, H}, title = {Extraction of heavy metal complexes from a biofilm colony for biomonitoring the pollution.}, journal = {Turkish journal of chemistry}, volume = {44}, number = {3}, pages = {712-725}, pmid = {33488188}, issn = {1300-0527}, abstract = {An extraction method was tested for biomonitoring the biofilm samples containing heavy metals. The fractionation of metal complexes was performed via C-18-HPLC-ICP-MS and MALDI-MS, respectively. The extraction power of some reagents was determined for the heavy metal extraction from biofilm samples collected in Erdemli coast in the Mediterranean Sea. The ammonium acetate solution giving the highest extraction results was found as a suitable extraction reagent. The concentration and pH of the ammonium acetate solution were optimized and found as 1 M and 5, respectively. The chromatograms of metal complexes with the C-18-HPLC-ICP-MS system were taken to determine the effect of the pH of the metal complexes. After performing the extraction, metal bounded biomolecules were characterized by MALDI-MS for the fractions in the C18-HPLC system. It was seen that ammonium acetate extraction (1M, pH 5) might be used in biomonitoring studies due to relatively simple procedure, short analysis period, and low cost. The evaluation of the applicability of the method in biomonitoring studies might be supported by further studies with biofilms having similar characteristics.}, } @article {pmid33488102, year = {2021}, author = {Seder, N and Abu Bakar, MH and Abu Rayyan, WS}, title = {Transcriptome Analysis of Pseudomonas aeruginosa Biofilm Following the Exposure to Malaysian Stingless Bee Honey.}, journal = {Advances and applications in bioinformatics and chemistry : AABC}, volume = {14}, number = {}, pages = {1-11}, pmid = {33488102}, issn = {1178-6949}, abstract = {INTRODUCTION: Malaysian stingless bee honey (Trigona) has been aroused as a potential antimicrobial compound with antibiofilm activity. The capability of the gram-negative bacillus P. aeruginosa to sustain a fatal infection is encoded in the bacterium genome.

METHODS: In the current study, a transcriptome investigation was performed to explore the mechanism underlying the biofilm dispersal of P. aeruginosa after the exposure to Trigona honey.

RESULTS: Microarray analysis of the Pseudomonas biofilm treated by 20% Trigona honey has revealed a down-regulation of 3478 genes among the 6085 screened genes. Specifically, around 13.5% of the down-regulated genes were biofilm-associated genes. The mapping of the biofilm-associated pathways has shown an ultimate decrease in the expression levels of the D-GMP signaling pathway and diguanylate cyclases (DGCs) genes responsible for c-di-GMP formation.

CONCLUSION: We predominantly report the lowering of c-di-GMP through the down-regulation of DGC genes as the main mechanism of biofilm inhibition by Trigona honey.}, } @article {pmid33486770, year = {2021}, author = {Srimaneepong, V and Thanamee, T and Wattanasirmkit, K and Muangsawat, S and Matangkasombut, O}, title = {Efficacy of low-molecular weight chitosan against Candida albicans biofilm on polymethyl methacrylate resin.}, journal = {Australian dental journal}, volume = {66}, number = {3}, pages = {262-269}, doi = {10.1111/adj.12826}, pmid = {33486770}, issn = {1834-7819}, support = {//Ratchadapiseksomphot Endowment Fund/ ; //Chulalongkorn University/ ; }, mesh = {Biofilms ; *Candida albicans ; *Chitosan/pharmacology ; Denture Bases ; Humans ; Molecular Weight ; Polymethyl Methacrylate ; Surface Properties ; }, abstract = {BACKGROUND: Candida biofilm is a major cause of denture stomatitis. We aimed to compare the efficacy of low-molecular-weight chitosan solutions against Candida albicans biofilm on polymethyl methacrylate (PMMA) resin.

METHODS: Various types of chitosan were tested for anti-Candida activity by broth dilution. Two types were selected for further testing on 24-hour C.albicans biofilm formed on PMMA specimens. Specimens were randomly distributed among experimental groups, including 0.1% and 0.2% acetic acid, 3 and 6 mg/mL of oligomer chitosan and 30 kDa chitosan solutions, effervescent tablet (Polident), and 0.2% chlorhexidine, and immersed for 5 min to 12 h. The viability of C. albicans after cleansing were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Remaining viability was calculated into percentage relative to respective controls and analyzed using ANOVA with Tukey post-hoc tests. Live/dead fluorescence microscopy was also performed.

RESULTS: Chitosan solutions had high efficacy against C. albicans biofilm on PMMA. The mean relative viability compared to control after 12-h immersion was 6.60 ± 4.75% and 12.72 ± 6.96% for 3 and 6 mg/mL oligomer, respectively, and 11.68 ± 4.81% and 18.08 ± 6.20% for 3 and 6 mg/mL 30 kDa chitosan, respectively.

CONCLUSIONS: Low-molecular-weight chitosan solution is an effective antifungal denture cleanser that can significantly reduce C. albicans viability in biofilm on PMMA.}, } @article {pmid33485132, year = {2021}, author = {Fan, Y and Su, J and Wang, Z and Deng, L and Zhang, H}, title = {Impact of C/N ratio on the fate of simultaneous Ca[2+] precipitation, F[-] removal, and denitrification in quartz sand biofilm reactor.}, journal = {Chemosphere}, volume = {273}, number = {}, pages = {129667}, doi = {10.1016/j.chemosphere.2021.129667}, pmid = {33485132}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; Nitrates ; *Nitrogen ; Quartz ; Sand ; Wastewater ; }, abstract = {The coexistence of F[-], Ca[2+], nitrates, and other pollutants in water body has aroused widespread concern. In this research, a novel quartz sand biofilm reactor was established, aiming to study the key factors of different carbon to nitrogen (C/N) ratios (5:1, 4:1, and 3:1), initial Ca[2+] concentration (180 mg L[-1], 144 mg L[-1], and 108 mg L[-1]), and hydraulic retention time (HRT) (4 h, 6 h, and 8 h) on simultaneous Ca[2+] precipitation, F[-] removal, and denitrification. Results showed that the removal efficiencies of Ca[2+], F[-], and nitrate were 55.04%, 82.64%, and 97.69% under the low C/N ratio of 3:1, initial Ca[2+] concentration of 180 mg L[-1], and HRT of 8 h. 3-D Excitation-Emission Fluorescence Spectroscopy (3-D EEM) demonstrates that extracellular polymeric substances (EPS) was generated during the growth metabolism. Scanning Electron Microscopy (SEM) and X-ray diffractometer images showed that Ca[2+], F[-] removed in the form of CaCO3, Ca5(PO4)3F and CaF2 under Acinetobacter sp. H12 induction. Moreover, high-throughput sequencing results display that the biomineralized bacteria Acinetobacter sp. H12 exerted great influence in the bioreactor. This research will underpin the practical use of multiple pollutants such as F[-] and Ca[2+] wastewater under the different C/N ratios.}, } @article {pmid33485083, year = {2021}, author = {Xiao, W and Xu, G and Li, G}, title = {Role of shear stress in biological aerated filter with nanobubble aeration: Performance, biofilm structure and microbial community.}, journal = {Bioresource technology}, volume = {325}, number = {}, pages = {124714}, doi = {10.1016/j.biortech.2021.124714}, pmid = {33485083}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; *Microbiota ; Oxygen ; Wastewater ; }, abstract = {This study comprehensively investigated the role of shear stress in a biological aerated filter under nanobubble aeration with the operation of an internal reflux and mechanical bubbling, where nanobubbles provide an opportunity to separately assess the effect of the hydraulic shear stress and aeration on the properties of the biofilms. Shear stress optimized the oxygen distribution, which improved the dissolved oxygen of the effluent three- and four-fold through reflux and mechanical bubbling, respectively. Proper shear stress enhanced the spatial development of the biofilms and promoted the activity and stability of nanobubble-aerated biofilms, achieving a sufficient contaminant removal efficiency that meets the local standard. Shear stress and aeration individually regulated the functional pathways and improved the development of the biofilm structure and the performance. The results indicate that nanobubble is a promising aeration technology when accompanied by a shearing strategy.}, } @article {pmid33484812, year = {2021}, author = {Fang, R and Liu, H and Zhang, X and Dong, G and Li, J and Tian, X and Wu, Z and Zhou, J and Cao, J and Zhou, T}, title = {Difference in biofilm formation between carbapenem-resistant and carbapenem-sensitive Klebsiella pneumoniae based on analysis of mrkH distribution.}, journal = {Microbial pathogenesis}, volume = {152}, number = {}, pages = {104743}, doi = {10.1016/j.micpath.2021.104743}, pmid = {33484812}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Carbapenems/pharmacology ; Humans ; *Klebsiella Infections ; *Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; beta-Lactamases ; }, abstract = {OBJECT: To analyze the difference in biofilm formation between carbapenem-resistant and carbapenem-sensitive Klebsiella pneumoniae based on analysis of mrkH distribution and to further explore the function of mrkH for biofilm formation from the perspective of gene regulation.

METHODS: 40 imipenem-resistant strains and 40 imipenem-sensitive strains were selected to conduct experiments. Carbapenem (imipenem) susceptibility test was performed by the agar-dilution method. blaKPC resistance gene, type 3 fimbriae-related coding genes (mrkA and mrkD) and regulation gene (mrkH) were screened by PCR. Biofilm formation assay was performed using crystal violet staining method in MHB. The relative expression of genes that critically involved in biofilm formation (mrkA, luxS, pgaA) and carbapenem resistance (ompk35, ompk36, acrB) were measured by quantitative real-time PCR (qRT-PCR). Furthermore, the mrkH cassette was cloned into pGEM-T Easy plasmid to yield pGEM:pmrkH and expressed in Escherichia coli DH5α and K. pneumoniae FK1911, and the biofilm formation assay after transformation was further tested.

RESULTS: The MICs of imipenem were all more than 16 μg/mL in 40 imipenem-resistant strains and ranged from 0.125 μg/mL to 0.5 μg/mL in 40 imipenem-sensitive strains. Moreover, the blaKPC was identified in the 40 imipenem-resistant K. pneumoniae strains. All 80 K. pneumoniae strains were found to carry mrkA and mrkD genes. Interestingly, the mrkH gene was detected in 43 strains, of which 32 were carbapenem-sensitive strains. The biofilm formation capacity of strains carried mrkH cassette was significantly higher than other 37 strains in MHB media. The relative expression of mrkA in K. pneumoniae carrying mrkH gene was significantly up-regulated. Importantly, the biofilm formation ability of FK1911-pGEM:pmrkH strain was more higher than the strain of FK1911 in MHB medium.

CONCLUSIONS: Our data demonstrated that MrkH played a crucial role in the regulation of biofilm formation by K. pneumoniae. In contrast to carbapenem-sensitive K. pneumoniae, carbapenem-resistant K. pneumoniae was less likely to have strong biofilm-forming capacity because it does not carry the mrkH gene.}, } @article {pmid33482719, year = {2021}, author = {Barger, PC and Liles, MR and Beck, BH and Newton, JC}, title = {Correction to: Differential production and secretion of potentially toxigenic extracellular proteins from hypervirulent Aeromonas hydrophila under biofilm and planktonic culture.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {33}, pmid = {33482719}, issn = {1471-2180}, } @article {pmid33481065, year = {2021}, author = {Miwa, T and Takimoto, Y and Hatamoto, M and Kuratate, D and Watari, T and Yamaguchi, T}, title = {Role of live cell colonization in the biofilm formation process in membrane bioreactors treating actual sewage under low organic loading rate conditions.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {4}, pages = {1721-1729}, pmid = {33481065}, issn = {1432-0614}, support = {19J15362 and 19H01163//Japan Society for the Promotion of Science/ ; }, mesh = {Biofilms ; *Bioreactors ; Membranes, Artificial ; RNA, Ribosomal, 16S/genetics ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {Biofilm development on the membrane surface is one of the main reasons for membrane fouling in membrane bioreactors (MBRs) and it is a big problem for their stable operation. Precise information on the microbial community composition of the biofilm is needed for a better understanding of biofilm development. However, there have been limited investigations of the relationship between the biofilm formation process and the microbial community of activated sludge and biofilm in MBRs treating real sewage. In this study, relationships between the microbial community structure of biofilm and activated sludge at each biofilm formation stage were investigated and biofilm growth was elucidated by nondestructive observations. Two anoxic/oxic MBRs were operated and membrane fouling was induced. Permeability rapidly decreased in both reactors and live cell microcolonies were formed on dead cell conditioning film on the membrane surface. Principal component analysis based on 16S rRNA gene sequences showed that the biofilm microbial community changed significantly from middle stage to mature biofilm when compared with that of activated sludge. The abundance of specific bacteria, such as unclassified Neisseriaceae, increased in middle-stage biofilm and the diversity indexes of middle-stage biofilm were lower than those of mature biofilm and activated sludge. These results suggested that the presence of specific bacteria with colonization ability played a crucial role in biofilm formation. Strategies are needed to target membrane fouling mitigation during early- and middle-stage biofilm formation to reduce MBR membrane fouling. KEY POINTS: • Microbial community of mature biofilm was approached to that of activated sludge. • In the middle-stage biofilm, live cells colonized on a dead-cell-conditioning-film. • Microbial diversity was lower in live cell colonizing stage than in activated sludge.}, } @article {pmid33480316, year = {2022}, author = {Sarkar, S and Tribedi, P and Bhadra, K}, title = {Structure-activity insights of harmine targeting DNA, ROS inducing cytotoxicity with PARP mediated apoptosis against cervical cancer, anti-biofilm formation and in vivo therapeutic study.}, journal = {Journal of biomolecular structure & dynamics}, volume = {40}, number = {13}, pages = {5880-5902}, doi = {10.1080/07391102.2021.1874533}, pmid = {33480316}, issn = {1538-0254}, mesh = {Animals ; *Antineoplastic Agents/chemistry ; Apoptosis ; DNA/chemistry ; Female ; Harmine/chemistry/metabolism/pharmacology ; HeLa Cells ; Humans ; Mice ; Molecular Docking Simulation ; Poly(ADP-ribose) Polymerase Inhibitors/pharmacology ; Prospective Studies ; Reactive Oxygen Species ; *Uterine Cervical Neoplasms ; }, abstract = {Harmine exhibits pH dependent structural equilibrium and possesses numerous biological and pharmacological activities. Mode and mechanism of DNA binding and its cytotoxicity were studied by multiple spectroscopic, calorimetric, molecular docking and in vitro apoptotic as well as in vivo biochemical and histological studies. It exists as cationic (structure I) and decationic form (structure II) in the pH range 3.0-7.8 and 8.5-12.4, respectively, with a pKa of 8.0. Structure I at pH 6.8 binds strongly to DNA with a cooperative mode of binding of Kiω 1.03 × 10[6] M[-1]and stoichiometry of 5.0 nucleotide phosphates. Structure I stabilized DNA by 10 °C, showed85%quenching of fluorescence intensity, perturbation in circular dichroism, partial intercalation and enthalpy driven exothermic binding. While, structure II at pH 8.5 has very weak interaction with CT DNA. Cytotoxic potencies of structure I was tested on four different cancer cell lines along with normal embryonic cell. It showed maximum cytotoxicity with GI50of 20 µM, against HeLa causing several apoptotic induction abilities. Harmine exhibited G2M arrest with ROS induced effective role in PARP mediated apoptosis as well as anti-inflammatory action on HeLa cells. Harmine further presented MIC and antibiofilm activity against Staphylococcus aureus in presence of <160 and 30 µg/ml, respectively. Mice with post harmine treatment (30 mg/kg b.w., I.P.) showed maximum recovery from damaged to near normal architecture of cervical epithelial cells. This study may be of prospective use in a framework to design novel beta carboline compounds for improved therapeutic applications in future against cervical cancer. HighlightsHarmine exists in structure I and structure II forms in the pH 6.8 and 8.5with a pKa of 8.0.Structure I at pH 6.8 binds strongly to DNA compared to structure II.Structure I showed maximum cytotoxicity with GI50 of 20 µM against HeLa.ROS mediated cytotoxicitywithG2M arrest with PARP mediated apoptosis was studied.Harmine (30µg/ml) exhibited antibiofilm activity against Staphylococcus aureus.Post harmine dose (30 mg/kg b.w., I.P.) in mice showed recovery of cervical epithelial cells.Communicated by Ramaswamy H. Sarma.}, } @article {pmid33480137, year = {2021}, author = {Pati, BA and Kurata, WE and Horseman, TS and Pierce, LM}, title = {Antibiofilm activity of chitosan/epsilon-poly-L-lysine hydrogels in a porcine ex vivo skin wound polymicrobial biofilm model.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {29}, number = {2}, pages = {316-326}, doi = {10.1111/wrr.12890}, pmid = {33480137}, issn = {1524-475X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Peptides ; Biofilms ; *Chitosan/pharmacology ; Hydrogels/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Polylysine/pharmacology ; Pseudomonas aeruginosa ; Swine ; Wound Healing ; *Wound Infection/drug therapy ; }, abstract = {As antibiotic resistance continues to increase globally, there is an urgency for novel, non-antibiotic approaches to control chronic drug-resistant infections, particularly those associated with polymicrobial biofilm formation in chronic wounds. Also needed are clinically relevant polymicrobial biofilm models that can be utilized to assess the efficacy of innovative therapeutics against mature biofilms. We successfully developed a highly reproducible porcine ex vivo skin wound polymicrobial biofilm model using clinical isolates of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. This ex vivo biofilm model was then used to assess the antimicrobial and antibiofilm properties of an easily fabricated chitosan hydrogel incorporating the natural antimicrobial peptide epsilon-poly-L-lysine. Antimicrobial activity was evaluated against planktonic cultures in vitro and against mature biofilms ex vivo. The antibiofilm efficiency of the hydrogels was especially pronounced against Pseudomonas aeruginosa, whose counts were reduced by 99.98% after 2 hours in vitro and by 99.94% after treatment for 24 hours when applied to 24 hour ex vivo polymicrobial wound biofilms. The activity of the hydrogels was lower against Staphylococcus aureus and ineffective against Candida albicans. Gram, Hucker-Twort staining of paraffin sections revealed balanced polymicrobial communities in mature 48 hour untreated biofilms. Treatment of 48 or 72 hour biofilms for 2 or 3 days with hydrogels that were applied within 5 hours after inoculation resulted in an impressive 96% and 97% reduction in biofilm thickness compared to untreated biofilms, respectively (P < .001). Likewise, topical gel treatment for 24 hours reduced biofilm thickness by 84% and 70%, respectively, when applied to mature biofilms at 24 and 48 hours after inoculation (P < .001). Thus, this ex vivo wound biofilm model provides a useful means to assess the efficacy of novel treatments to prevent and eradicate polymicrobial biofilms consisting of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans.}, } @article {pmid33479476, year = {2021}, author = {Khong, NZ and Zeng, Y and Lai, SK and Koh, CG and Liang, ZX and Chiam, KH and Li, HY}, title = {Dynamic swimming pattern of Pseudomonas aeruginosa near a vertical wall during initial attachment stages of biofilm formation.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {1952}, pmid = {33479476}, issn = {2045-2322}, support = {RG-44/16//Ministry of Education - Singapore/ ; RG-138/16//Ministry of Education - Singapore/ ; }, mesh = {*Biofilms ; Pseudomonas aeruginosa/*physiology ; *Swimming ; }, abstract = {Studying the swimming behaviour of bacteria in 3 dimensions (3D) allows us to understand critical biological processes, such as biofilm formation. It is still unclear how near wall swimming behaviour may regulate the initial attachment and biofilm formation. It is challenging to address this as visualizing the movement of bacteria with reasonable spatial and temporal resolution in a high-throughput manner is technically difficult. Here, we compared the near wall (vertical) swimming behaviour of P. aeruginosa (PAO1) and its mutants ΔdipA (reduced in swarming motility and increased in biofilm formation) and ΔfimX (deficient in twitching motility and reduced in biofilm formation) using our new imaging technique based on light sheet microscopy. We found that P. aeruginosa (PAO1) increases its speed and changes its swimming angle drastically when it gets closer to a wall. In contrast, ΔdipA mutant moves toward the wall with steady speed without changing of swimming angle. The near wall behavior of ΔdipA allows it to be more effective to interact with the wall or wall-attached cells, thus leading to more adhesion events and a larger biofilm volume during initial attachment when compared with PAO1. Furthermore, we found that ΔfimX has a similar near wall swimming behavior as PAO1. However, it has a higher dispersal frequency and smaller biofilm formation when compared with PAO1 which can be explained by its poor twitching motility. Together, we propose that near wall swimming behavior of P. aeruginosa plays an important role in the regulation of initial attachment and biofilm formation.}, } @article {pmid33478627, year = {2021}, author = {Rath, S and Bal, SCB and Dubey, D}, title = {Oral Biofilm: Development Mechanism, Multidrug Resistance, and Their Effective Management with Novel Techniques.}, journal = {Rambam Maimonides medical journal}, volume = {12}, number = {1}, pages = {}, pmid = {33478627}, issn = {2076-9172}, abstract = {Biofilms are formed by the congregation of one or more types of microorganisms that can grow on a firm surface. Dental plaque is one of the most commonly forming biofilms in the oral cavity and appears as a slimy layer on the surface of the teeth. In general, the formation is slow, but biofilms are very adaptive to the changing environment, and a mature biofilm can cause many health-related problems in humans. These biofilms remain unaffected by antibiotics as they do not allow the penetration of antibiotics. Moreover, the increased level of virulence and antibiotic resistance of microorganisms in the oral biofilm or dental plaque has made its clinical management a serious challenge worldwide. Chlorhexidine-like antimicrobial drugs have been partially effective in removing such organisms; however, the precise and continuous elimination of these microorganisms without disturbing the normal microbial flora of the oral cavity is still a challenge. This review paper focuses on the process of oral biofilm formation, related complications, development of drug-resistant bacteria in these biofilms, and their effective management by the use of different novel techniques, available from various published research and review articles.}, } @article {pmid33478312, year = {2021}, author = {Vaitkus, S and Simoes-Torigoe, R and Wong, N and Morris, K and Spada, FE and Alagiri, M and Talke, FE}, title = {A comparative study of experimental urinary catheters containing silver and zinc for biofilm inhibition.}, journal = {Journal of biomaterials applications}, volume = {35}, number = {8}, pages = {1071-1081}, doi = {10.1177/0885328221989553}, pmid = {33478312}, issn = {1530-8022}, mesh = {Anti-Infective Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Coated Materials, Biocompatible/chemistry/pharmacology ; Dimethylpolysiloxanes/chemistry ; Escherichia coli/drug effects/growth & development ; Reactive Oxygen Species/analysis ; Silver/chemistry/*pharmacology ; Urinary Catheters/*microbiology ; Zinc/chemistry/*pharmacology ; }, abstract = {Both commercial and experimental antibacterial urinary catheters were investigated for their efficacy in preventing planktonic growth and biofilm formation of Escherichia Coli bacteria in a synthetic urine solution. Experimental antibacterial catheters having thin (<500 µm) dispersions of Ag, Ag/Ag2O, or Zn/Ag2O in polydimethylsiloxane (PDMS) binder all exhibited significant antimicrobial activity, outperforming traditional commercial antibacterial catheters. All experimental catheters prevented planktonic growth of bacteria and did not exhibit biofilm formation during a six-day test period using a colony forming unit (CFU) measurement method. On the other hand, the best performing commercial catheters demonstrated efficacy for only 3 days in planktonic growth tests and formed multiple bacterial colonies in CFU measurements. The Zn/Ag2O/PDMS experimental catheter was the only catheter observed to produce hydrogen peroxide, a reactive oxygen species known to inhibit biofilm formation; lack of detectable hydrogen peroxide production by the Ag2O/PDMS and Ag/Ag2O/PDMS experimental catheters suggests that bactericidal action most likely arises from release of silver ions present in the PDMS coatings.}, } @article {pmid33477546, year = {2021}, author = {Recalde, A and van Wolferen, M and Sivabalasarma, S and Albers, SV and Navarro, CA and Jerez, CA}, title = {The Role of Polyphosphate in Motility, Adhesion, and Biofilm Formation in Sulfolobales.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33477546}, issn = {2076-2607}, support = {grants Nº 1150791 and partially by No 1191554 both to CAJ.//Fondo Nacional de Desarrollo Científico y Tecnológico/ ; 403222702-SFB 1381//Deutsche Forschungsgemeinschaft/ ; 94933//VW Stiftung to MvW/ ; }, abstract = {Polyphosphates (polyP) are polymers of orthophosphate residues linked by high-energy phosphoanhydride bonds that are important in all domains of life and function in many different processes, including biofilm development. To study the effect of polyP in archaeal biofilm formation, our previously described Sa. solfataricus polyP (-) strain and a new polyP (-) S. acidocaldarius strain generated in this report were used. These two strains lack the polymer due to the overexpression of their respective exopolyphosphatase gene (ppx). Both strains showed a reduction in biofilm formation, decreased motility on semi-solid plates and a diminished adherence to glass surfaces as seen by DAPI (4',6-diamidino-2-phenylindole) staining using fluorescence microscopy. Even though arlB (encoding the archaellum subunit) was highly upregulated in S. acidocardarius polyP (-), no archaellated cells were observed. These results suggest that polyP might be involved in the regulation of the expression of archaellum components and their assembly, possibly by affecting energy availability, phosphorylation or other phenomena. This is the first evidence indicating polyP affects biofilm formation and other related processes in archaea.}, } @article {pmid33477397, year = {2021}, author = {Pitangui, NS and de Lacorte Singulani, J and Sardi, JCO and de Souza, PC and Rodríguez-Arellanes, G and García-Pérez, BE and Enguita, FJ and Pavan, FR and Taylor, ML and Mendes-Giannini, MJS and Fusco-Almeida, AM}, title = {Differential miRNA Expression in Human Macrophage-Like Cells Infected with Histoplasma capsulatum Yeasts Cultured in Planktonic and Biofilm Forms.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {1}, pages = {}, pmid = {33477397}, issn = {2309-608X}, support = {480316/2012-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; -//Programa de Apoio ao Desenvolvimento Científico (PADC)/ ; 2013/05853-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; IN217418//Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica-Dirección General de Asuntos del Personal Académico (PAPIIT-DGAPA/UNAM-MX)/ ; -//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {Histoplasma capsulatum affects healthy and immunocompromised individuals, sometimes causing a severe disease. This fungus has two morphotypes, the mycelial (infective) and the yeast (parasitic) phases. MicroRNAs (miRNAs) are small RNAs involved in the regulation of several cellular processes, and their differential expression has been associated with many disease states. To investigate miRNA expression in host cells during H. capsulatum infection, we studied the changes in the miRNA profiles of differentiated human macrophages infected with yeasts from two fungal strains with different virulence, EH-315 (high virulence) and 60I (low virulence) grown in planktonic cultures, and EH-315 grown in biofilm form. MiRNA profiles were evaluated by means of reverse transcription-quantitative polymerase chain reaction using a commercial human miRNome panel. The target genes of the differentially expressed miRNAs and their corresponding signaling pathways were predicted using bioinformatics analyses. Here, we confirmed biofilm structures were present in the EH-315 culture whose conditions facilitated producing insoluble exopolysaccharide and intracellular polysaccharides. In infected macrophages, bioinformatics analyses revealed especially increased (hsa-miR-99b-3p) or decreased (hsa-miR-342-3p) miRNAs expression levels in response to infection with biofilms or both growth forms of H. capsulatum yeasts, respectively. The results of miRNAs suggested that infection by H. capsulatum can affect important biological pathways of the host cell, targeting two genes: one encoding a protein that is important in the cortical cytoskeleton; the other, a protein involved in the formation of stress granules. Expressed miRNAs in the host's response could be proposed as new therapeutic and/or diagnostic tools for histoplasmosis.}, } @article {pmid33477393, year = {2021}, author = {Guerini, M and Grisoli, P and Pane, C and Perugini, P}, title = {Microstructured Lipid Carriers (MLC) Based on N-Acetylcysteine and Chitosan Preventing Pseudomonas aeruginosa Biofilm.}, journal = {International journal of molecular sciences}, volume = {22}, number = {2}, pages = {}, pmid = {33477393}, issn = {1422-0067}, mesh = {Acetylcysteine/*pharmacology ; Anti-Infective Agents/pharmacology ; Biofilms/drug effects ; Chitosan/*pharmacology ; Drug Delivery Systems/*methods ; Drug Liberation ; Lipids/pharmacology ; Microbial Sensitivity Tests ; Nanoparticles ; Particle Size ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects/metabolism ; }, abstract = {The aim of this work was the development of microstructured lipid carriers (MLC) based on chitosan (CH) and containing N-acetylcysteine (NAC), a mucolytic and antioxidant agent, to inhibit the formation of Pseudomonas aeruginosa biofilm. MLC were prepared using the high shear homogenization technique. The MLC were characterized for morphology, particle size, Z potential, encapsulation efficiency and drug release. The antioxidant properties of NAC-loaded microstructured carriers were evaluated through an in vitro spectrophotometer assay. Finally, the activity of NAC-CH-MLC on biofilm production by Pseudomonas aeruginosa was also evaluated. Results obtained from this study highlighted that the use of chitosan into the inner aqueous phase permitted to obtain microstructured particles with a narrow size range and with good encapsulation efficiency. NAC-loaded MLC showed higher antioxidant activity than the free molecule, demonstrating how encapsulation increases the antioxidant effect of the molecule. Furthermore, the reduction of biofilm growth resulted extremely high with MLC being 64.74% ± 6.2% and 83.74% ± 9.95%, respectively, at 0.5 mg/mL and 2 mg/mL. In conclusion, this work represents a favorable technological strategy against diseases in which bacterial biofilm is relevant, such as cystic fibrosis.}, } @article {pmid33477349, year = {2021}, author = {Krasowski, G and Junka, A and Paleczny, J and Czajkowska, J and Makomaska-Szaroszyk, E and Chodaczek, G and Majkowski, M and Migdał, P and Fijałkowski, K and Kowalska-Krochmal, B and Bartoszewicz, M}, title = {In Vitro Evaluation of Polihexanide, Octenidine and NaClO/HClO-Based Antiseptics against Biofilm Formed by Wound Pathogens.}, journal = {Membranes}, volume = {11}, number = {1}, pages = {}, pmid = {33477349}, issn = {2077-0375}, support = {2017/27/B/NZ6/02103//National Science Center/ ; A-1//B. Braun Medical AG,Sempach, Switzerland/ ; }, abstract = {Chronic wounds complicated with biofilm formed by pathogens remain one of the most significant challenges of contemporary medicine. The application of topical antiseptic solutions against wound biofilm has been gaining increasing interest among clinical practitioners and scientific researchers. This paper compares the activity of polyhexanide-, octenidine- and hypochlorite/hypochlorous acid-based antiseptics against biofilm formed by clinical strains of Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The analyses included both standard techniques utilizing polystyrene plates and self-designed biocellulose-based models in which a biofilm formed by pathogens was formed on an elastic, fibrinous surface covered with a fibroblast layer. The obtained results show high antibiofilm activity of polihexanide- and octenidine-based antiseptics and lack or weak antibiofilm activity of hypochlorite-based antiseptic of total chlorine content equal to 80 parts per million. The data presented in this paper indicate that polihexanide- or octenidine-based antiseptics are highly useful in the treatment of biofilm, while hypochlorite-based antiseptics with low chlorine content may be applied for wound rinsing but not when specific antibiofilm activity is required.}, } @article {pmid33476485, year = {2021}, author = {Malone, M and Radzieta, M and Schwarzer, S and Jensen, SO and Lavery, LA}, title = {Efficacy of a topical concentrated surfactant gel on microbial communities in non-healing diabetic foot ulcers with chronic biofilm infections: A proof-of-concept study.}, journal = {International wound journal}, volume = {18}, number = {4}, pages = {457-466}, pmid = {33476485}, issn = {1742-481X}, mesh = {Bacteria ; Biofilms ; *Diabetes Mellitus ; *Diabetic Foot/drug therapy ; Humans ; *Microbiota ; Surface-Active Agents ; }, abstract = {This proof-of-concept study sought to determine the effects of standard of care (SOC) and a topically applied concentrated surfactant gel (SG) on the total microbial load, community composition, and community diversity in non-healing diabetic foot ulcers (DFUs) with chronic biofilm infections. SOC was provided in addition to a topical concentrated SG, applied every 2 days for 6 weeks. Wound swabs were obtained from the base of ulcers at baseline (week 0), week 1, mid-point (week 3), and end of treatment (week 6). DNA sequencing and real-time quantitative polymerase chain reaction (qPCR) were employed to determine the total microbial load, community composition, and diversity of patient samples. Tissue specimens were obtained at baseline and scanning electron microscopy and peptide nucleic acid fluorescent in situ hybridisation with confocal laser scanning microscopy were used to confirm the presence of biofilm in all 10 DFUs with suspected chronic biofilm infections. The application of SG resulted in 7 of 10 samples achieving a reduction in mean log10 total microbial load from baseline to end of treatment (0.8 Log10 16S copies, ±0.6), and 3 of 10 samples demonstrated an increase in mean Log10 total microbial load (0.6 log10 16S copies, ±0.8) from baseline to end of treatment. Composition changes in microbial communities were driven by changes to the most dominant bacteria. Corynebacterium sp. and Streptococcus sp. frequently reduced in relative abundance in patient samples from week 0 to week 6 but did not disappear. In contrast, Staphylococcus sp., Finegoldia sp., and Fusobacterium sp., relative abundances frequently increased in patient samples from week 0 to week 6. The application of a concentrated SG resulted in varying shifts to diversity (increase or decrease) between week 0 and week 6 samples at the individual patient level. Any shifts in community diversity were independent to changes in the total microbial loads. SOC and a topical concentrated SG directly affect the microbial loads and community composition of DFUs with chronic biofilm infections.}, } @article {pmid33474610, year = {2021}, author = {Chatterjee, B and Vittal, RR}, title = {Quorum sensing modulatory and biofilm inhibitory activity of Plectranthus barbatus essential oil: a novel intervention strategy.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1767-1778}, pmid = {33474610}, issn = {1432-072X}, support = {Project No (ERIP/ER/201611002/M/01/1672 dated 22nd June 2017//Defence Research and Development Organisation/ ; ERIP/ER/201611002/M/01/1672 dated 22nd June 2017//Defence Research and Development Organisation/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Chromobacterium/drug effects/metabolism ; Escherichia coli/drug effects ; Gas Chromatography-Mass Spectrometry ; Indoles/metabolism ; Listeria monocytogenes/drug effects ; Oils, Volatile/*pharmacology ; Plant Extracts/pharmacology ; Plant Oils/*pharmacology ; Plectranthus/*chemistry ; Pseudomonas aeruginosa/drug effects ; Quorum Sensing/*drug effects ; Salmonella typhimurium/drug effects ; }, abstract = {The essential oil (EO) from the roots of Plectranthus barbatus Andr. (Syn. Coleus forskohlii Briq.) was evaluated for quorum sensing (QS) inhibitory activity. P. barbatus EO was screened for inhibition of QS regulated violacein production in Chromobacterium violaceum (ATCC 12472) wild-type strain. At inhibitory (6.25% v/v) and sub-inhibitory concentrations (3.125% v/v) of the EO, dose-dependent response in the inhibition of violacein production was observed in C. violaceum. Similarly, sub-MIC (6.25% v/v) of P. barbatus EO disrupted QS regulated biofilm formation by 27.87% and inhibited swarming and twitching motility in Pseudomonas aeruginosa PA01 implying its anti-infective and QS modulatory activity. Fluorescence microscopy studies confirmed the disruption of biofilm formation by EO in P. aeruginosa PAO1. Promising antibacterial activity was recorded at concentrations as low as 3.12% v/v for Listeria monocytogenes (ATCC 13932) and at 6.25% v/v for both Salmonella enterica subsp. enterica serovar Typhimurium (ATCC 25241) and Escherichia coli (ATCC 11775). Furthermore, significant dose-dependent inhibition was observed for biofilm formation and motility in all the tested pathogens in different treated concentrations. GC-MS analysis revealed α-pinene, endo-borneol, bornyl acetate, 1-Hexyl-2-Nitrocyclohexane as the major phytoconstituents. P. barbatus EO or its constituent compounds with QS modulatory, antimicrobial and biofilm inhibitory property could be potential new-age dietary source based intervention and preservation technologies.}, } @article {pmid33474508, year = {2021}, author = {Crampon, M and Hellal, J and Mouvet, C and Ollivier, P}, title = {Degradation of tetrachloroethylene by zero valent iron nanoparticles in the presence of a natural groundwater bacterial biofilm in a sandy porous media.}, journal = {Heliyon}, volume = {7}, number = {1}, pages = {e05854}, pmid = {33474508}, issn = {2405-8440}, abstract = {Biofilms are naturally present in aquifers and can interact with zero valent iron nanoparticles (nZVI) used as remediation agents in contaminated groundwater; thereby they may alter nZVI reactivity towards targeted contaminants in porous media. Laboratory scale experiments using columns filled with sand (50 cm long and 5.2 cm in diameter) were performed to investigate the impact of natural biofilms on nZVI reactivity towards tetrachloroethylene (PCE) in conditions simulating an unconsolidated sandy aquifer. Solutions containing PCE were injected through the sand columns in the presence or absence of biofilm and nZVI. Concentrations in PCE and its metabolites were monitored during 45 days in dissolved and gas phases. PCE concentrations decreased at the column outlets due both to its reductive dechlorination by nZVI (~30% of injected PCE) and its sorption or deposition (as PCE-DNAPL) on sand (~35% of injected PCE). No significant differences in PCE concentrations were found in presence or absence of biofilm. However, biofilm presence affected the nature of PCE metabolites. A higher release of ethene in the column containing biofilm was observed, whereas ethane was dominant in the absence of biofilm. Microbes consumed H2 released by the corrosion of nZVI limiting the hydrogenation of ethene to ethane. The consequences of biofilm development in porous media should be taken into account when considering treatment with nZVI, as it may affect the nature of produced metabolites.}, } @article {pmid33470844, year = {2021}, author = {Santos Carvalhais, BE and Souza E Silva, C and Dos Santos, KV}, title = {Effect of antimicrobials on Stenotrophomonas maltophilia biofilm.}, journal = {Future microbiology}, volume = {16}, number = {2}, pages = {83-93}, doi = {10.2217/fmb-2020-0115}, pmid = {33470844}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ceftazidime/pharmacology ; Drug Resistance, Multiple, Bacterial ; Gram-Negative Bacterial Infections/*microbiology ; Humans ; Levofloxacin/pharmacology ; Microbial Sensitivity Tests ; Minocycline/pharmacology ; Stenotrophomonas maltophilia/*drug effects/growth & development/physiology ; Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology ; }, abstract = {Aim: To evaluate the activity of five antimicrobials against young and mature Stenotrophomonas maltophilia biofilms. Materials & methods: Nineteen clinical strains from hemoculture of hemodialysis patients were tested for biofilm kinetics, MIC and minimum biofilm inhibitory concentration (MBIC) in young and mature biofilms. Results: All strains were moderate biofilm producers. MIC showed total susceptibility to levofloxacin and trimethoprim-sulfamethoxazole and partial resistance to ceftazidime (63.2%) and gentamicin (21%). Young and mature biofilms showed the lowest MBIC/MIC ratio for gentamicin, chloramphenicol and levofloxacin, respectively. The highest MBIC/MIC was for trimethoprim-sulfamethoxazole (young) and ceftazidime (mature). Conclusion: Gentamicin displayed surprising activity against S. maltophilia biofilms. Chloramphenicol was indicated as a good option against young S. maltophilia biofilms, and trimethoprim-sulfamethoxazole showed limited antibiofilm activity.}, } @article {pmid33470545, year = {2021}, author = {Yu, K and Alzahrani, A and Khoddami, S and Ferreira, D and Scotland, KB and Cheng, JTJ and Yazdani-Ahmadabadi, H and Mei, Y and Gill, A and Takeuchi, LE and Yeung, E and Grecov, D and Hancock, REW and Chew, BH and Lange, D and Kizhakkedathu, JN}, title = {Self-Limiting Mussel Inspired Thin Antifouling Coating with Broad-Spectrum Resistance to Biofilm Formation to Prevent Catheter-Associated Infection in Mouse and Porcine Models.}, journal = {Advanced healthcare materials}, volume = {10}, number = {6}, pages = {e2001573}, doi = {10.1002/adhm.202001573}, pmid = {33470545}, issn = {2192-2659}, support = {//CIHR/Canada ; }, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; *Catheter-Related Infections/prevention & control ; Escherichia coli ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Mice ; Swine ; Urinary Catheters ; }, abstract = {Catheter-associated urinary tract infections (CAUTIs) are one of the most commonly occurring hospital-acquired infections. Current coating strategies to prevent catheter-associated biofilm formation are limited by their poor long-term efficiency and limited applicability to diverse materials. Here, the authors report a highly effective non-fouling coating with long-term biofilm prevention activity and is applicable to diverse catheters. The thin coating is lubricous, stable, highly uniform, and shows broad spectrum prevention of biofilm formation of nine different bacterial strains and prevents the migration of bacteria on catheter surface. The coating method is adapted to human-sized catheters (both intraluminal and extraluminal) and demonstrates long-term biofilm prevention activity over 30 days in challenging conditions. The coated catheters are tested in a mouse CAUTI model and demonstrate high efficiency in preventing bacterial colonization of both Gram-positive and Gram-negative bacteria. Furthermore, the coated human-sized Foley catheters are evaluated in a porcine CAUTI model and show consistent efficiency in reducing biofilm formation by Escherichia coli (E. coli) over 95%. The simplicity of the coating method, the ability to apply this coating on diverse materials, and the high efficiency in preventing bacterial adhesion increase the potential of this method for the development of next generation infection resistant medical devices.}, } @article {pmid33470479, year = {2021}, author = {Manoharadas, S and Altaf, M and Alrefaei, AF and Hussain, SA and Devasia, RM and Badjah Hadj, AYM and Abuhasil, MSA}, title = {Microscopic analysis of the inhibition of staphylococcal biofilm formation by Escherichia coli and the disruption of preformed staphylococcal biofilm by bacteriophage.}, journal = {Microscopy research and technique}, volume = {84}, number = {7}, pages = {1513-1521}, doi = {10.1002/jemt.23707}, pmid = {33470479}, issn = {1097-0029}, support = {RG-1439-075//Deanship of Scientific Research, King Saud University/ ; //King Saud University/ ; }, mesh = {*Bacteriophages ; Biofilms ; *Escherichia coli ; Pseudomonas aeruginosa ; Staphylococcus aureus ; }, abstract = {The formation of bacterial biofilms is a severely encountered problem in clinical and industrial settings. Most of the naturally occurring bacterial strains are capable of forming mono or mixed biofilms. In this study, we evaluated the potentiality of three clinically relevant species in forming mono and mixed biofilms over glass surface. In addition, we also appraised the efficiency of bacteriophages in alleviating preformed mono and mixed biofilm. Our initial study focused on the ability of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in forming biofilm on glass cover slip. All the three strains were able to form mono biofilm, although at varying intensities. Interestingly, E. coli inhibited the formation of S. aureus biofilm in a mixed culture. Specific bacteriophages ɸ44AHJD and ɸX174 completely disrupted S. aureus and E. coli preformed biofilm structure after 72 hr of incubation. However, addition of either of the bacteriophage to the mixed E. coli-S. aureus promoted the formation of biofilm by the alternate strain that was not affected by the phage. Our findings elicit the potentiality of common bacterial strains in forming biofilms on smooth glass surface. In addition, these results are very promising for the development of effective drugs using intact bacteriophages for the removal of complicated bacterial biofilms formed in clinically relevant glass surfaces. The observations further complemented the earlier finding of competitive inhibition of S. aureus biofilm development by E. coli.}, } @article {pmid33469194, year = {2021}, author = {Kathwate, GH and Shinde, RB and Mohan Karuppayil, S}, title = {Non-antifungal drugs inhibit growth, morphogenesis and biofilm formation in Candida albicans.}, journal = {The Journal of antibiotics}, volume = {74}, number = {5}, pages = {346-353}, pmid = {33469194}, issn = {1881-1469}, mesh = {Antifungal Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Microbial Sensitivity Tests ; }, abstract = {The increased resistance/tolerance of Candida infections to antimicrobial treatment can be attributed to biofilm-associated cells. A way to overcome this situation is to re-purpose non-anti-fungal drugs that could be active against fungi. We have explored the potential of a small library of eighteen non-antifungal drugs used in different human diseases. Candida albicans was cultured in the presence and absence of different concentrations of these drugs. Subsequently, inhibition of growth, germ tube formation, adhesion, and biofilm development were studied. Out of eighteen drug molecules, six showed a reduction in planktonic and biofilm growth in a dose-dependent manner and three drugs inhibited germ tube formation. This study shows the potential of non-antifungal drugs for the development of new anti-Candida agents.}, } @article {pmid33468596, year = {2021}, author = {Keogh, RA and Zapf, RL and Frey, A and Marino, EC and Null, GG and Wiemels, RE and Holzschu, DL and Shaw, LN and Carroll, RK}, title = {Staphylococcus aureus Trigger Factor Is Involved in Biofilm Formation and Cooperates with the Chaperone PpiB.}, journal = {Journal of bacteriology}, volume = {203}, number = {7}, pages = {}, pmid = {33468596}, issn = {1098-5530}, support = {R01 AI124458/AI/NIAID NIH HHS/United States ; R21 AI128376/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Animals ; Bacterial Proteins ; Biofilms/*growth & development ; Blood/microbiology ; Cell-Free System ; Gene Expression Regulation, Bacterial/*physiology ; Gene Expression Regulation, Enzymologic ; Hemolysis ; Humans ; Mice ; Molecular Chaperones ; Peptidylprolyl Isomerase/genetics/*metabolism ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/genetics/*metabolism/physiology ; }, abstract = {Peptidyl-prolyl cis/trans isomerases (PPIases) are enzymes that assist in protein folding around proline-peptide bonds, and they often possess chaperone activity. Staphylococcus aureus encodes three PPIases, i.e., PrsA, PpiB, and trigger factor (TF). Previous work by our group demonstrated a role for both PrsA and PpiB in S. aureus; however, TF remains largely unstudied. Here, we identify a role for TF in S. aureus biofilm formation and demonstrate cooperation between TF and the cytoplasmic PPIase PpiB. Mutation of the tig gene (encoding TF) led to reduced biofilm development in vitro but no significant attenuation of virulence in a mouse model of infection. To investigate whether TF possesses chaperone activity, we analyzed the ability of a tig mutant to survive acid and base stress. While there was no significant decrease for a tig mutant, a ppiBtig double mutant exhibited significant decreases in cell viability after acid and base challenges. We then demonstrated that a ppiB tig double mutant had exacerbated phenotypes in vitro and in vivo, compared to either single mutant. Finally, in vivo immunoprecipitation of epitope-tagged PpiB revealed that PpiB interacted with 4 times the number of proteins when TF was absent from the cell, suggesting that it may be compensating for the loss of TF. Interestingly, the only proteins found to interact with TF were TF itself, fibronectin-binding protein B (FnBPB), and the chaperone protein ClpB. Collectively, these results support the first phenotype for S. aureus TF and demonstrate a greater network of cooperation between chaperone proteins in Staphylococcus aureusIMPORTANCES. aureus encodes a large number of virulence factors that aid the bacterium in survival and pathogenesis. These virulence factors have a wide variety of functions; however, they must all be properly secreted in order to be functional. Bacterial chaperone proteins often assist in secretion by trafficking proteins to secretion machinery or assisting in proper protein folding. Here, we report that the S. aureus chaperone TF contributes to biofilm formation and cooperates with the chaperone PpiB to regulate S. aureus virulence processes. These data highlight the first known role for TF in S. aureus and suggest that S. aureus chaperone proteins may be involved in a greater regulatory network in the cell.}, } @article {pmid33468578, year = {2021}, author = {Faozia, S and Fahmi, T and Port, GC and Cho, KH}, title = {c-di-AMP-Regulated K[+] Importer KtrAB Affects Biofilm Formation, Stress Response, and SpeB Expression in Streptococcus pyogenes.}, journal = {Infection and immunity}, volume = {89}, number = {4}, pages = {}, pmid = {33468578}, issn = {1098-5522}, mesh = {Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; Biological Transport ; Cation Transport Proteins/genetics/*metabolism ; Dinucleoside Phosphates/*metabolism ; Exotoxins/*genetics ; *Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions/immunology ; Mutation ; Open Reading Frames ; Potassium ; Streptococcal Infections/*microbiology ; Streptococcus pyogenes/*physiology ; Stress, Physiological ; Virulence ; }, abstract = {The second messenger cyclic di-AMP (c-di-AMP) controls biofilm formation, stress response, and virulence in Streptococcus pyogenes The deletion of the c-di-AMP synthase gene, dacA, results in pleiotropic effects including reduced expression of the secreted protease SpeB. Here, we report a role for K[+] transport in c-di-AMP-mediated SpeB expression. The deletion of ktrB in the ΔdacA mutant restores SpeB expression. KtrB is a subunit of the K[+] transport system KtrAB that forms a putative high-affinity K[+] importer. KtrB forms a membrane K[+] channel, and KtrA acts as a cytosolic gating protein that controls the transport capacity of the system by binding ligands including c-di-AMP. SpeB induction in the ΔdacA mutant by K[+] specific ionophore treatment also supports the importance of cellular K[+] balance in SpeB production. The ΔdacA ΔktrB double deletion mutant not only produces wild-type levels of SpeB but also partially or fully reverts the defective ΔdacA phenotypes of biofilm formation and stress responses, suggesting that many ΔdacA phenotypes are due to cellular K[+] imbalance. However, the null pathogenicity of the ΔdacA mutant in a murine subcutaneous infection model is not restored by ktrB deletion, suggesting that c-di-AMP controls not only cellular K[+] balance but also other metabolic and/or virulence pathways. The deletion of other putative K[+] importer genes, kup and kimA, does not phenocopy the deletion of ktrB regarding SpeB induction in the ΔdacA mutant, suggesting that KtrAB is the primary K[+] importer that is responsible for controlling cellular K[+] levels under laboratory growth conditions.}, } @article {pmid33468317, year = {2021}, author = {Choonharuangdej, S and Srithavaj, T and Thummawanit, S}, title = {Fungicidal and inhibitory efficacy of cinnamon and lemongrass essential oils on Candida albicans biofilm established on acrylic resin: An in vitro study.}, journal = {The Journal of prosthetic dentistry}, volume = {125}, number = {4}, pages = {707.e1-707.e6}, doi = {10.1016/j.prosdent.2020.12.017}, pmid = {33468317}, issn = {1097-6841}, mesh = {Acrylic Resins ; Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; Cinnamomum zeylanicum ; *Cymbopogon ; Humans ; *Oils, Volatile/pharmacology ; }, abstract = {STATEMENT OF PROBLEM: It is unclear whether cinnamon and lemongrass essential oils can effectively reduce the Candida-biofilm frequently formed on dental devices made from heat-polymerized polymethyl methacrylate (PMMA) resin that contributes to the development of mild oropharyngeal as well as life-threatening candidiasis in patients wearing the devices.

PURPOSE: The purpose of this in vitro study was to determine the efficacy of cinnamon and lemongrass essential oils in eradicating Candida albicans biofilm on heat-polymerized PMMA specimens and to determine whether they retard the formation of fungal biofilm.

MATERIAL AND METHODS: The antifungal effect of cinnamon and lemongrass essential oils was determined by using agar disk diffusion and broth microdilution methods to obtain minimum inhibitory concentrations. The mature C albicans biofilm (48 hours) was pre-established on PMMA specimens before being individually treated with various concentrations (½, 1, 2, 4, 8, 16 times minimum inhibitory concentration) of each tested oil for different exposure times (1, 2, 4, 8, and 24 hours). In another experiment, fungal biofilm was established on the PMMA specimens that were primed individually with various concentrations of the tested oils for different times. The 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT)-reduction assay was used to quantitate biofilm viability in both experiments. Statistical analysis was performed by using the 1-sample Kolmogorov-Smirnov test and 2-way ANOVA followed by the Tukey multiple comparison test (α=.05).

RESULTS: Minimum inhibitory concentration values of cinnamon and lemongrass essential oils against planktonic C albicans were 0.1 μL/mL (0.01% v/v) and 0.4 μL/mL (0.04% v/v). At 8 times the minimum inhibitory concentration, cinnamon oil (0.8 μL/mL or 0.08% v/v) and lemongrass oil (3.2 μL/mL or 0.32% v/v) eradicated the pre-established fungal biofilm by 99.0% in an exposure time of 1 hour. In contrast, high concentrations of 8 and 16 times the minimum inhibitory concentration of cinnamon oil (0.8 μL/mL or 0.08% v/v) and lemongrass oil (6.4 μL/mL or 0.64% v/v) coated on PMMA specimens for 24 hours were only able to inhibit the formation of fungal biofilm by approximately 70.0%.

CONCLUSIONS: Cinnamon and lemongrass essential oils can eliminate pre-established C albicans biofilm and restrain the formation of fungal biofilm on heat-polymerized PMMA specimens. Both effects of the tested essential oils depended on dose and exposure or priming time.}, } @article {pmid33467766, year = {2021}, author = {El-Baz, AM and Mosbah, RA and Goda, RM and Mansour, B and Sultana, T and Dahms, TES and El-Ganiny, AM}, title = {Back to Nature: Combating Candida albicans Biofilm, Phospholipase and Hemolysin Using Plant Essential Oils.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33467766}, issn = {2079-6382}, abstract = {Candida albicans is the causative agent of fatal systemic candidiasis. Due to limitations of antifungals, new drugs are needed. The anti-virulence effect of plant essential oils (EOs) was evaluated against clinical C. albicans isolates including cinnamon, clove, jasmine and rosemary oils. Biofilm, phospholipase and hemolysin were assessed phenotypically. EOs were evaluated for their anti-virulence activity using phenotypic methods as well as scanning electron microscopy (SEM) and atomic force microscopy (AFM). Among the C. albicans isolates, biofilm, phospholipase and hemolysins were detected in 40.4, 86.5 and 78.8% of isolates, respectively. Jasmine oil showed the highest anti-biofilm activity followed by cinnamon, clove and rosemary oils. SEM and AFM analysis showed reduced adherence and roughness in the presence of EOs. For phospholipase, rosemary oil was the most inhibitory, followed by jasmine, cinnamon and clove oils, and for hemolysins, cinnamon had the highest inhibition followed by jasmine, rosemary and clove oils. A molecular docking study revealed major EO constituents as promising inhibitors of the Als3 adhesive protein, with the highest binding for eugenol, followed by 1,8-cineole, 2-phenylthiolane and cinnamaldehyde. In conclusion, EOs have a promising inhibitory impact on Candida biofilm, phospholipase and hemolysin production, hence EOs could be used as potential antifungals that impact virulence factors.}, } @article {pmid33467548, year = {2021}, author = {Oliveira, VC and Macedo, AP and Melo, LDR and Santos, SB and Hermann, PRS and Silva-Lovato, CH and Paranhos, HFO and Andrade, D and Watanabe, E}, title = {Bacteriophage Cocktail-Mediated Inhibition of Pseudomonas aeruginosa Biofilm on Endotracheal Tube Surface.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33467548}, issn = {2079-6382}, support = {2018/09757-0, 2019/13271-9, 2020/03405-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 405622/2018-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {Although different strategies to control biofilm formation on endotracheal tubes have been proposed, there are scarce scientific data on applying phages for both removing and preventing Pseudomonas aeruginosa biofilms on the device surface. Here, the anti-biofilm capacity of five bacteriophages was evaluated by a high content screening assay. We observed that biofilms were significantly reduced after phage treatment, especially in multidrug-resistant strains. Considering the anti-biofilm screens, two phages were selected as cocktail components, and the cocktail's ability to prevent colonization of the endotracheal tube surface was tested in a dynamic biofilm model. Phage-coated tubes were challenged with different P. aeruginosa strains. The biofilm growth was monitored from 24 to 168 h by colony forming unit counting, metabolic activity assessment, and biofilm morphology observation. The phage cocktail promoted differences of bacterial colonization; nonetheless, the action was strain dependent. Phage cocktail coating did not promote substantial changes in metabolic activity. Scanning electron microscopy revealed a higher concentration of biofilm cells in control, while tower-like structures could be observed on phage cocktail-coated tubes. These results demonstrate that with the development of new coating strategies, phage therapy has potential in controlling the endotracheal tube-associated biofilm.}, } @article {pmid33466613, year = {2021}, author = {Zheng, Y and Wang, D and Ma, LZ}, title = {Effect of Polyhexamethylene Biguanide in Combination with Undecylenamidopropyl Betaine or PslG on Biofilm Clearance.}, journal = {International journal of molecular sciences}, volume = {22}, number = {2}, pages = {}, pmid = {33466613}, issn = {1422-0067}, support = {91951204, 31570126, 32070033， 2019YFA0905501//National Natural Science Foundation of China， and the National Basic Research Program of Chin/ ; }, mesh = {Bacteria/drug effects ; Bacterial Infections/prevention & control ; Betaine/analogs & derivatives/*pharmacology ; Biguanides/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects/physiology ; Candidiasis/prevention & control ; Cross Infection/prevention & control ; Disinfectants/*pharmacology ; Glycoside Hydrolases/*pharmacology ; Humans ; Pseudomonas aeruginosa/drug effects/*enzymology ; Undecylenic Acids/chemistry/pharmacology ; }, abstract = {Hospital-acquired infection is a great challenge for clinical treatment due to pathogens' biofilm formation and their antibiotic resistance. Here, we investigate the effect of antiseptic agent polyhexamethylene biguanide (PHMB) and undecylenamidopropyl betaine (UB) against biofilms of four pathogens that are often found in hospitals, including Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, Gram-positive bacteria Staphylococcus aureus, and pathogenic fungus, Candida albicans. We show that 0.02% PHMB, which is 10-fold lower than the concentration of commercial products, has a strong inhibitory effect on the growth, initial attachment, and biofilm formation of all tested pathogens. PHMB can also disrupt the preformed biofilms of these pathogens. In contrast, 0.1% UB exhibits a mild inhibitory effect on biofilm formation of the four pathogens. This concentration inhibits the growth of S. aureus and C. albicans yet has no growth effect on P. aeruginosa or E. coli. UB only slightly enhances the anti-biofilm efficacy of PHMB on P. aeruginosa biofilms. However, pretreatment with PslG, a glycosyl hydrolase that can efficiently inhibit and disrupt P. aeruginosa biofilm, highly enhances the clearance effect of PHMB on P. aeruginosa biofilms. Meanwhile, PslG can also disassemble the preformed biofilms of the other three pathogens within 30 min to a similar extent as UB treatment for 24 h.}, } @article {pmid33466540, year = {2021}, author = {Maione, A and de Alteriis, E and Carraturo, F and Galdiero, S and Falanga, A and Guida, M and Di Cosmo, A and Maselli, V and Galdiero, E}, title = {The Membranotropic Peptide gH625 to Combat Mixed Candida albicans/Klebsiella pneumoniae Biofilm: Correlation between In Vitro Anti-Biofilm Activity and In Vivo Antimicrobial Protection.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {1}, pages = {}, pmid = {33466540}, issn = {2309-608X}, abstract = {The antibiofilm activity of a gH625 analogue was investigated to determine the in vitro inhibition and eradication of a dual-species biofilm of Candida albicans and Klebsiella pneumoniae, two leading opportunistic pathogens responsible for several resistant infections. The possibility of effectively exploiting this peptide as an alternative anti-biofilm strategy in vivo was assessed by the investigation of its efficacy on the Galleria mellonella larvae model. Results on larvae survival demonstrate a prophylactic efficacy of the peptide towards the infection of each single microorganism but mainly towards the co-infection. The expression of biofilm-related genes in vivo showed a possible synergy in virulence when these two species co-exist in the host, which was effectively prevented by the peptide. These findings provide novel insights into the treatment of medically relevant bacterial-fungal interaction.}, } @article {pmid33466319, year = {2021}, author = {Souissi, M and Ben Lagha, A and Chaieb, K and Grenier, D}, title = {Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33466319}, issn = {2079-6382}, abstract = {The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol[®], for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel-chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol[®], which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.}, } @article {pmid33466318, year = {2021}, author = {Nesse, LL and Mo, SS and Ramstad, SN and Witsø, IL and Sekse, C and Bruvoll, AEE and Urdahl, AM and Vestby, LK}, title = {The Effect of Antimicrobial Resistance Plasmids Carrying blaCMY-2 on Biofilm Formation by Escherichia coli from the Broiler Production Chain.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33466318}, issn = {2076-2607}, support = {250212//Research Council of Norway,/ ; 31142//Norwegian Veterinary Institute/ ; }, abstract = {Extended-spectrum cephalosporin-resistant Escherichia coli (ESCR E. coli) with plasmids carrying the blaCMY-2 resistance gene have been isolated from the Norwegian broiler production chain through the Norwegian monitoring program for antimicrobial resistance in animals, food and feed, NORM-VET. The aim of the present study was to investigate the biofilm forming abilities of these strains, and in particular to see whether these might be influenced by the carriage of blaCMY-2 plasmids. The ESCR E. coli from the broiler production chain displayed relatively low biofilm forming abilities in the crystal violet biofilm assay as compared to quinolone-resistant E. coli (QREC) from the same population (mean ± SD = 0.686 ± 0.686 vs. 1.439 ± 0.933, respectively). Acquisition of two different blaCMY-2 plasmids by QREC strains reduced their biofilm production in microtiter plates, but not their biofilm production on Congo Red agar plates. Furthermore, motility was reduced, but not planktonic growth. We hypothesize that genes carried by these plasmids may have caused the observed reduction in biofilm formation, possibly mediated through changes in flagellar expression or function. Furthermore, this may help explain the different biofilm forming abilities observed between ESCR E. coli and QREC. The results also indicate that the risk of biofilm reservoirs of antimicrobial resistant E. coli on in the broiler production is lower for ESCR E. coli than for QREC.}, } @article {pmid33465647, year = {2021}, author = {Zhou, L and Zhao, B and Ou, P and Zhang, W and Li, H and Yi, S and Zhuang, WQ}, title = {Core nitrogen cycle of biofoulant in full-scale anoxic & oxic biofilm-membrane bioreactors treating textile wastewater.}, journal = {Bioresource technology}, volume = {325}, number = {}, pages = {124667}, doi = {10.1016/j.biortech.2021.124667}, pmid = {33465647}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; Nitrogen ; Oxidation-Reduction ; Textiles ; *Wastewater ; }, abstract = {Core nitrogen cycle within biofoulant in full-scale anoxic & oxic biofilm-membrane bioreactor (bMBR) treating textile wastewater was investigated. Wastewater filtered through membrane with biofoulant had elevated NH4[+]-N and NO2[-]-N concentrations corresponding to decreased NO3[-]-N concentrations. Nevertheless, total nitrogen concentrations did not change significantly, indicating negligible nitrogen removal activities within biofoulant. Metagenomic analysis revealed a lack of genes, such as AmoCAB and Hao in biofoulant, indicating absence of nitrification or anammox populations. However, genes encoding complete pathway for dissimilatory nitrate reduction to ammonium (DNRA) were discovered in 15 species that also carry genes encoding both nitrate reductase and nitrite reductase. No specie contained all genes for complete denitrification pathway. High temperature, high C:N ratio, and anoxic conditions of textile wastewater could favorite microbes growth with DNRA pathway over those with canonical denitrification pathway. High dissolved oxygen concentrations could effectively inhibit DNRA to minimize ammonia concentration in the effluent.}, } @article {pmid33465305, year = {2021}, author = {Pirhanov, A and Bridges, CM and Goodwin, RA and Guo, YS and Furrer, J and Shor, LM and Gage, DJ and Cho, YK}, title = {Optogenetics in Sinorhizobium meliloti Enables Spatial Control of Exopolysaccharide Production and Biofilm Structure.}, journal = {ACS synthetic biology}, volume = {10}, number = {2}, pages = {345-356}, doi = {10.1021/acssynbio.0c00498}, pmid = {33465305}, issn = {2161-5063}, mesh = {Bacterial Proteins/metabolism ; Binding Sites ; Biofilms/*growth & development ; Gene Expression/radiation effects ; Gene Expression Regulation, Bacterial/radiation effects ; Light ; Optogenetics/*methods ; Plant Roots/microbiology ; Polysaccharides, Bacterial/*biosynthesis ; Ribosomes/metabolism ; Signal Transduction/*radiation effects ; Sinorhizobium meliloti/*genetics/*metabolism ; Soil Microbiology ; Sphingomonadaceae/metabolism ; Symbiosis/genetics ; Transcription Factors/metabolism ; }, abstract = {Microorganisms play a vital role in shaping the soil environment and enhancing plant growth by interacting with plant root systems. Because of the vast diversity of cell types involved, combined with dynamic and spatial heterogeneity, identifying the causal contribution of a defined factor, such as a microbial exopolysaccharide (EPS), remains elusive. Synthetic approaches that enable orthogonal control of microbial pathways are a promising means to dissect such complexity. Here we report the implementation of a synthetic, light-activated, transcriptional control platform using the blue-light responsive DNA binding protein EL222 in the nitrogen fixing soil bacterium Sinorhizobium meliloti. By fine-tuning the system, we successfully achieved optical control of an EPS production pathway without significant basal expression under noninducing (dark) conditions. Optical control of EPS recapitulated important behaviors such as a mucoid plate phenotype and formation of structured biofilms, enabling spatial control of biofilm structures in S. meliloti. The successful implementation of optically controlled gene expression in S. meliloti enables systematic investigation of how genotype and microenvironmental factors together shape phenotype in situ.}, } @article {pmid33465146, year = {2021}, author = {Devaraj, A and González, JF and Eichar, B and Thilliez, G and Kingsley, RA and Baker, S and Allard, MW and Bakaletz, LO and Gunn, JS and Goodman, SD}, title = {Enhanced biofilm and extracellular matrix production by chronic carriage versus acute isolates of Salmonella Typhi.}, journal = {PLoS pathogens}, volume = {17}, number = {1}, pages = {e1009209}, pmid = {33465146}, issn = {1553-7374}, support = {BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10348/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 215515/Z/19/Z/WT_/Wellcome Trust/United Kingdom ; R21 AI153752/AI/NIAID NIH HHS/United States ; BB/R012504/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; R01 AI116917/AI/NIAID NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Antibodies, Monoclonal/pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; DnaB Helicases/antagonists & inhibitors/genetics/*metabolism ; Extracellular Matrix/*metabolism ; Humans ; Integration Host Factors/genetics/*metabolism ; Salmonella typhi/classification/genetics/*pathogenicity ; Typhoid Fever/drug therapy/immunology/*microbiology ; }, abstract = {Salmonella Typhi is the primary causative agent of typhoid fever; an acute systemic infection that leads to chronic carriage in 3-5% of individuals. Chronic carriers are asymptomatic, difficult to treat and serve as reservoirs for typhoid outbreaks. Understanding the factors that contribute to chronic carriage is key to development of novel therapies to effectively resolve typhoid fever. Herein, although we observed no distinct clustering of chronic carriage isolates via phylogenetic analysis, we demonstrated that chronic isolates were phenotypically distinct from acute infection isolates. Chronic carriage isolates formed significantly thicker biofilms with greater biomass that correlated with significantly higher relative levels of extracellular DNA (eDNA) and DNABII proteins than biofilms formed by acute infection isolates. Importantly, extracellular DNABII proteins include integration host factor (IHF) and histone-like protein (HU) that are critical to the structural integrity of bacterial biofilms. In this study, we demonstrated that the biofilm formed by a chronic carriage isolate in vitro, was susceptible to disruption by a specific antibody against DNABII proteins, a successful first step in the development of a therapeutic to resolve chronic carriage.}, } @article {pmid33464842, year = {2020}, author = {Xie, Y and Zhang, M and Zhang, W and Liu, X and Zheng, W and Jiang, X}, title = {Gold Nanoclusters-Coated Orthodontic Devices Can Inhibit the Formation of Streptococcus mutans Biofilm.}, journal = {ACS biomaterials science & engineering}, volume = {6}, number = {2}, pages = {1239-1246}, doi = {10.1021/acsbiomaterials.9b01647}, pmid = {33464842}, issn = {2373-9878}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Dental Caries/prevention & control ; Gold ; Humans ; *Streptococcus mutans ; }, abstract = {Oral health is an issue that has attracted increasing attention recently. Poor oral hygiene may induce the formation of oral biofilm on orthodontic devices, and cause gingivitis and dental caries. Here, we present a strategy for modifying orthodontic devices (e.g., invisalign aligner) with quaternary ammonium (QA)-modified gold nanoclusters (QA-GNCs) as an antibiotic reagent to prevent bacterial contamination and biofilm formation. The QA-GNCs-coated aligner can efficiently inhibit the adhesion of cariogenic pathogenic Streptococcus mutans and the formation of biofilm. Moreover, the antibacterial activity of the coated QA-GNCs can be maintained for at least 3 months and after repeated usage (>3 cycles). Furthermore, the QA-GNCs coating shows excellent biosafety confirmed by the cell viability test, the hemolysis assay, and animal experiments. Our strategy for antibacterial coating has the advantages of broad applications, low cost, good stability, high antibacterial efficiency, good biocompatibility, and low risk of antibiotic contamination, which could be particularly useful in preventing infections involving implantable medical devices or wearable electronics.}, } @article {pmid33464417, year = {2021}, author = {Nascimento, GG and Leite, FRM and Pennisi, PRC and López, R and Paranhos, LR}, title = {Use of air polishing for supra- and subgingival biofilm removal for treatment of residual periodontal pockets and supportive periodontal care: a systematic review.}, journal = {Clinical oral investigations}, volume = {25}, number = {3}, pages = {779-795}, pmid = {33464417}, issn = {1436-3771}, support = {307808/2018-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {*Biofilms ; *Dental Polishing ; Dental Scaling ; Glycine ; Humans ; Periodontal Pocket ; Root Planing ; }, abstract = {AIM: To systematically review the literature to compare the efficacy of air polishing to hand or ultrasonic instrumentation to reduce periodontal inflammation during treatment of residual pockets or supportive periodontal care.

METHODS: Electronic searches were performed in five different databases, and two databases were used to capture the "grey literature partially." Clinical trials that compared the use of an air-polishing device to either conventional scaling and root planing (hand and/or ultrasonic instrumentation) or no treatment during periodontal therapy were included without restriction of year and publication status. The Joanna Briggs Institute instrument for clinical trials was used to appraise the studies critically. The results were submitted to qualitative descriptive analysis. The systematic review protocol was registered in PROSPERO (CRD420220156176).

RESULTS: Electronic searches found 1100 hits published between 2008 and 2019. Thirteen studies were included in the review, out of which four had a follow-up longer than 180 days. Results indicated no differences between the efficacy of air polishing and hand or ultrasonic instruments to reduce periodontal inflammation.

CONCLUSIONS: Our findings suggest that there is no difference in the efficacy of air polishing and hand or ultrasonic instrumentation to control biofilm and reduce periodontal inflammation. However, these findings must be carefully interpreted owing to methodological issues, including a short follow-up, and a potential conflict of interest related to industry funding.

CLINICAL RELEVANCE: Air polishing for biofilm control may be used as an alternative to hand and ultrasonic instrumentation to reduce periodontal inflammation during treatment of residual pockets or supportive periodontal care.}, } @article {pmid33463231, year = {2020}, author = {Quan, K and Zhang, Z and Ren, Y and Busscher, HJ and van der Mei, HC and Peterson, BW}, title = {Homogeneous Distribution of Magnetic, Antimicrobial-Carrying Nanoparticles through an Infectious Biofilm Enhances Biofilm-Killing Efficacy.}, journal = {ACS biomaterials science & engineering}, volume = {6}, number = {1}, pages = {205-212}, doi = {10.1021/acsbiomaterials.9b01425}, pmid = {33463231}, issn = {2373-9878}, mesh = {*Anti-Infective Agents ; *Biofilms ; Magnetic Phenomena ; *Nanoparticles ; }, abstract = {Magnetic, antimicrobial-carrying nanoparticles provide a promising, new and direly needed antimicrobial strategy against infectious bacterial biofilms. Penetration and accumulation of antimicrobials over the thickness of a biofilm is a conditio sine qua non for effective killing of biofilm inhabitants. Simplified schematics on magnetic-targeting always picture homogeneous distribution of magnetic, antimicrobial-carrying nanoparticles over the thickness of biofilms, but this is not easy to achieve. Here, gentamicin-carrying magnetic nanoparticles (MNPs-G) were synthesized through gentamicin conjugation with iron-oxide nanoparticles and used to demonstrate the importance of their homogeneous distribution over the thickness of a biofilm. Diameters of MNPs-G were around 60 nm, well below the limit for reticuloendothelial rejection. MNPs-G killed most ESKAPE-panel pathogens, including Escherichia coli, equally as well as gentamicin in solution. MNPs-G distribution in a Staphylococcus aureus biofilm was dependent on magnetic-field exposure time and most homogeneous after 5 min magnetic-field exposure. Exposure of biofilms to MNPs-G with 5 min magnetic-field exposure yielded not only homogeneous distribution of MNPs-G, but concurrently better staphylococcal killing at all depths than that of MNPs, gentamicin in solution, and MNPs-G, or after other magnet-field exposure times. In summary, homogeneous distribution of gentamicin-carrying magnetic nanoparticles over the thickness of a staphylococcal biofilm was essential for killing biofilm inhabitants and required optimizing of the magnetic-field exposure time. This conclusion is important for further successful development of magnetic, antimicrobial-carrying nanoparticles toward clinical application.}, } @article {pmid33462691, year = {2021}, author = {Al-Maqtari, QA and Al-Ansi, W and Mahdi, AA and Al-Gheethi, AAS and Mushtaq, BS and Al-Adeeb, A and Wei, M and Yao, W}, title = {Supercritical fluid extraction of four aromatic herbs and assessment of the volatile compositions, bioactive compounds, antibacterial, and anti-biofilm activity.}, journal = {Environmental science and pollution research international}, volume = {28}, number = {20}, pages = {25479-25492}, pmid = {33462691}, issn = {1614-7499}, support = {2018GXZ018756//Chinese Government Scholarship/ ; BE2019362//Key R&D Program of Jiangsu Province/ ; SS2019016//Science and Technology Plan of Suzhou City/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Antioxidants ; *Chromatography, Supercritical Fluid ; Phenols/analysis ; Plant Extracts ; }, abstract = {Artemisia arborescens, Artemisia abyssinica, Pulicaria jaubertii, and Pulicaria petiolaris are fragrant herbs traditionally used in medication and as a food seasoning. To date, there are no studies on the use of supercritical fluids extraction with carbon dioxide (SFE-CO2) on these plants. This study evaluates and compares total phenolic content (TPC), antioxidant activity by DPPH[•] and ABTS[•+], antibacterial, and anti-biofilm activities of SFE-CO2 extracts. Extraction was done by SFE-CO2 with 10% ethanol as a co-solvent. A. abyssinica extract had the highest extraction yield (8.9% ± 0.41). The GC/MS analysis of volatile compounds identified 307, 265, 213, and 201compounds in A. abyssinica, A. arborescens, P. jaubertii, and P. petiolaris, respectively. The P. jaubertii extract had the highest TPC (662.46 ± 50.93 mg gallic acid equivalent/g dry extract), antioxidant activity (58.98% ± 0.20), and antioxidant capacity (71.78 ± 1.84 mg Trolox equivalent/g dry extract). The A. abyssinica and P. jaubertii extracts had significantly higher antimicrobial activity and were more effective against Gram-positive bacteria. B. subtilis was the most sensitive bacterium. P. aeruginosa was the most resistant bacterium. P. jaubertii extract had the optimum MIC and MBC (0.4 mg/ml) against B. subtilis. All SFE-CO2 extracts were effective as an anti-biofilm formation for all tested bacteria at 1/2 MIC. Meanwhile, P. jaubertii and P. petiolaris extracts were effective anti-biofilm for most tested bacteria at 1/16 MIC. Overall, the results indicated that the SFE-CO2 extracts of these plants are good sources of TPC, antioxidants, and antibacterial, and they have promising applications in the industrial fields.}, } @article {pmid33460747, year = {2021}, author = {Meena, H and Mishra, R and Ranganathan, S and Sarma, VV and Ampasala, DR and Siddhardha, B}, title = {Attenuation of quorum sensing mediated virulence factors production and biofilm formation in Pseudomonas aeruginosa PAO1 by Colletotrichum gloeosporioides HM3.}, journal = {Microbial pathogenesis}, volume = {151}, number = {}, pages = {104723}, doi = {10.1016/j.micpath.2020.104723}, pmid = {33460747}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/pharmacology ; Biofilms ; *Colletotrichum ; Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence ; Virulence Factors/genetics ; }, abstract = {Signal dependent microbial communication in Pseudomonas aeruginosa PAO1 is a typical phenomenon mediated by acyl homo-serine lactone molecules that helps in developing biofilm and enhance antibiotic resistance. Microbial sources provide insight to the hidden treasure of secondary metabolites, and these structurally diversified chemical motifs can be used as antimicrobial and anti-infective agents. In the present study, endophytic fungus, Colletotrichum gloeosporioides HM3 isolated from Carica papaya leaves was explored for anti-infective potential against P. aeruginosa PAO1. The crude extract of C. gloeosporioides HM3 displayed bacteriostatic effect on P. aeruginosa PAO1 growth at 750 μg/ml concentration. A significant decline was observed in the production of quorum sensing regulated virulence factors, i.e. 56.32%, 62.54%, and 66.67% of pyocyanin, chitinase, and elastase enzyme, respectively. A drastic reduction in pathogenic determinant behaviour after treatment with crude extract of C. gloeosporioides HM3 i.e. EPS, rhamnolipid, and HCN production was noted. Light microscopy and CLSM analysis revealed that fungal extract treatment has reduced bacterial ability to form dense biofilm architecture. In silico analysis demonstrated the binding efficiency of bioactive compound, 4-(2,3-dimethoxybenzylidene)-3-methyl-1-(4-nitrophenyl)-2-pyrazolin-5-one, which is equipotent to the natural ligand and displayed a docking score of -5.436 kcal/mol with QS transcriptional regulator (LasR). Whereas the compound Acetamide, n-[tetrahydro-3-(phenylmethyl) thieno [3,4-d]thiazol-2 (3 h)-ylidene]-, s,s-dioxide exhibits a docking score of -4.088 kcal/mol (LasR) and -1.868 kcal/mol (RhlR) with cognate receptor proteins. Henceforth, the research report suggests C. gloeosporioides HM3 derived metabolites could be considered as a potential inhibitors of QS regulated virulence factors and biofilm production in P. aeruginosa PAO1.}, } @article {pmid33460732, year = {2021}, author = {Raouf, M and Essa, S and El Achy, S and Essawy, M and Rafik, S and Baddour, M}, title = {Evaluation of Combined Ciprofloxacin and azithromycin free and nano formulations to control biofilm producing Pseudomonas aeruginosa isolated from burn wounds.}, journal = {Indian journal of medical microbiology}, volume = {39}, number = {1}, pages = {81-87}, doi = {10.1016/j.ijmmb.2021.01.004}, pmid = {33460732}, issn = {1998-3646}, mesh = {Animals ; Anti-Bacterial Agents/therapeutic use ; Azithromycin/*therapeutic use ; Biofilms/*drug effects ; Burns/microbiology ; Ciprofloxacin/*therapeutic use ; Drug Therapy, Combination ; Mice ; Microbial Sensitivity Tests ; Nanomedicine ; *Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects ; }, abstract = {BACKGROUND: Nanoparticles are becoming increasingly important against resistant superbugs including Pseudomonas aeruginosa infections.

AIMS: Exploration of Azithromycin as an adjunctive therapy to Ciprofloxacin for treatment of P. aeruginosa infections. Also, preparation of Ciprofloxacin-Azithromycin nanoparticles on chitosan nanocarrier (Cipro-AZM-CS) and assessment of its antimicrobial effect in vitro and in vivo.

METHODS: Detection of biofilm production and biofilm-specific antibiotic resistance ndvB and tssC1 genes was attempted. Minimal inhibitory concentration (MIC) and Minimum biofilm eradication concentration (MBEC) were done in vitro for assessment of P. aeruginosa planktonic and biofilm forms eradication, respectively. In In vivo study, Cipro-AZM-CS and free form were used to evaluate survival rate, wound contraction and bacterial load in mice after third degree burn.

RESULTS: All isolates were positive for biofilm production and ndvB and tssC1 genes. Majority of isolates (37, 74%) were extensively drug resistant. In the planktonic state, MIC values of Cipro-AZM free and CS forms were significantly lower than free Cipro MIC (P = 0.015 and P < 0.001 respectively). Also, Cipro-AZM free and CS MBEC values were significantly lower than that of free Cipro (P < 0.010 and P < 0.001 respectively). Furthermore, The MIC and MBEC values of free Cipro-AZM decreased significantly when challenged with Cipro-AZM-CS (P = 0.009 and P < 0.001 respectively). In vivo study combined free and Cipro-AZM-CS treated subgroups showed 100% mice survival with early resolution of infection and wound contraction (75%, 77.5% respectively) VS 45% for Cipro CS (P < 0.001).

CONCLUSION: Combined free and Cipro-AZM-CS showed promising results in vitro and in vivo overcoming high resistance of biofilm producing P. aeruginosa.}, } @article {pmid33459816, year = {2021}, author = {Sundaramoorthy, M and Karuppaiah, A and Nithyanth, M and Baberoselin, R and Ramesh, S and Geetha, N and Veintramuthu, S}, title = {Formulation development of cream with mupirocin and essential oils for eradication of biofilm mediated antimicrobial resistance.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1707-1715}, pmid = {33459816}, issn = {1432-072X}, support = {60(0117)/19/EMR-II//Central Leather Research Institute/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial/drug effects ; Eucalyptus Oil/pharmacology ; Eugenol/pharmacology ; Humans ; Microbial Sensitivity Tests ; Mupirocin/*pharmacology ; Oils, Volatile/*pharmacology ; Skin Cream/chemistry/pharmacology ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus (S.aureus) is both a colonizer as well as a human pathogen that causes a variety of diseases. Mupirocin is a topical antimicrobial agent which is very effective against S.aureus infection. However, treating the S.aureus infection using mupirocin could be complicated due to biofilm formation. Consequently, resistance to mupirocin occurs and leads to chronic infection. The combination of mupirocin with a compound that has biofilm eradicating effect would be an ideal solution for effectively treating biofilm infections. Therefore, in this study, we have investigated the biofilm inhibitory and eradication effect of mupirocin with three essential oils (Cinnamon Oil (CO), Eugenol (EU) and Eucalyptus Oil (EO)) against sessile S.aureus. From these preliminary results, it was found that the mupirocin-CO (0.2 µg/ml-5.218 mg/ml) combination has a better synergistic antibiofilm effect against sessile S.aureus and the fractional inhibitory concentration index was found to be 0.458. The best combination of mupirocin with CO was loaded into a non-greasy O/W cream. The physico-chemical and microbiological evaluations were carried out for the prepared cream. The prepared cream has better biofilm eradication activity (40%) when compared to a marketed cream (20%).}, } @article {pmid33458790, year = {2021}, author = {Di Marco, NI and Páez, PL and Lucero-Estrada, CSM and Pungitore, CR}, title = {Naphthoquinones inhibit formation and viability of Yersinia enterocolitica biofilm.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {2}, pages = {30}, pmid = {33458790}, issn = {1573-0972}, support = {PROICO 2-0914//Universidad Nacional de San Luis/ ; PROICO 02-2516//Universidad Nacional de San Luis/ ; PROICO 02-1518//Universidad Nacional de San Luis/ ; PICT-2015-1722//Fondo para la Investigación Científica y Tecnológica/ ; PICT-2017-0785//Fondo para la Investigación Científica y Tecnológica/ ; PROICO 02-1518//Fondo para la Investigación Científica y Tecnológica/ ; }, mesh = {Acyl-Butyrolactones/metabolism ; Biofilms/drug effects/*growth & development ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Microbial Viability ; Molecular Structure ; Naphthoquinones/chemistry/*pharmacology ; Oxidative Stress ; Yersinia enterocolitica/drug effects/*physiology ; }, abstract = {The capacity of different naphthoquinones to inhibit and eradicate Yersinia enterocolitica biofilm was investigated and possible mechanisms of action were evaluated. Inhibition of biofilm formation and cell viability, quorum sensing (QS) inhibition and oxidative stress generation of 23 naphthoquinones were assayed against Yersinia enterocolitica. The best anti-biofilm agents at 100 µmol l[-1] were compounds 3, 11 and 13, which showed biofilm inhibition higher than 75%. Compound 3 was the most effective against biofilm forming capacity of Y. enterocolitica WAP 314 with a minimum biofilm inhibitory concentration (MBIC) of 25 µmol l[-1]; while against Y. enterocolitica CLC001, the lowest MBIC was 6.1 µmol l[-1] for compound 11. Acyl-homoserine lactones production was decreased with compound 13. We showed that the oxidative stress influence biofilm growth, by means of ROS and RNI increment. All treatments increased ROS and RNI values in the biofilm of both strains; while in planktonic cells, the increase was lesser. Additionally, Y. enterocolitica WAP 314 biofilm treated with compounds 11 and 13 showed above 80% of SOD consumption. In Y. enterocolitica CLC001 biofilm all compounds induced above 90% of SOD consumption. The SOD activity was higher in biofilm than in planktonic cells. In conclusion, this is the first study to demonstrate that naphthoquinones are able to inhibit biofilm formation of Y. enterocolitica without critical disturbing its planktonic growth. Naphthoquinones as anti-biofilm agents might potentially be useful in the treatment of biofilm-associated infections in the future.}, } @article {pmid33456722, year = {2020}, author = {Chen, J and Chen, Z and Yuan, K and Huang, Z and Mao, M}, title = {Recombinant bacteriophage T4 Rnl1 impacts Streptococcus mutans biofilm formation.}, journal = {Journal of oral microbiology}, volume = {13}, number = {1}, pages = {1860398}, pmid = {33456722}, issn = {2000-2297}, abstract = {Bacteriophage T4 RNA ligase 1 (T4 Rnl1) can be stably expressed in many bacteria and has been reported to affect the bioactivity of the host bacteria. Recently, we constructed bacteriophage T4 Rnl1 expressing system in Streptococcus mutans, a crucial biofilm-forming and dental caries-causing oral pathogen. Here, we characterized the function of recombinant bacteriophage T4 Rnl1 in biofilm formation of S. mutans. The T4 Rnl1 mutant exhibited similar growth phenotype but resulted in a significant reduction of biofilm biomass compared to wild type strain and empty plasmid carrying strain. The abnormal biofilm of the T4 Rnl1 mutant harbored loose bacterial clusters with defective production and distribution of exopolysaccharides. Moreover, the expression of several biofilm formation-associated genes was dysregulated at mRNA level in the T4 Rnl1 mutant. These results reveal that the bacteriophage T4 Rnl1 exert antibiofilm activities against the cariogenic bacterium S. mutans, which impacts the spatial organization of the exopolysaccharides and further impairs the three-dimensional biofilm architecture. These findings implicate that manipulation of bacteriophage T4 Rnl1, a biological tool used for RNA ligation, will provide a promising approach to cariogenic biofilm control.}, } @article {pmid33453877, year = {2021}, author = {Guo, R and Luo, X and Liu, J and Lu, H}, title = {Mass spectrometry based targeted metabolomics precisely characterized new functional metabolites that regulate biofilm formation in Escherichia coli.}, journal = {Analytica chimica acta}, volume = {1145}, number = {}, pages = {26-36}, doi = {10.1016/j.aca.2020.12.021}, pmid = {33453877}, issn = {1873-4324}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Escherichia coli ; Mass Spectrometry ; Metabolomics ; }, abstract = {Biofilms are broadly formed by diverse microorganisms under stressful environments that are basically surrounded by an EPS matrix, which enable bacterial cells to confer the resistance to the biocides, antibiotics and other invasions. Yet, biofilms cause harmful impacts in various fields, including clinical infections, food contaminations and environmental pollution. However, the mechanism of biofilm formation remains incompletely elucidated, and currently, we lack an efficient strategy to tackle these tough problems by eradicating biofilms. In the present study, we sought to decipher the mechanism of biofilm formation in Escherichia coli from metabolic perspective. By exposing bacterial cells to various concentrations of iron, we found that iron can regulate biofilm formation, and the phenotypic changes were obviously dependent on iron concentration. A functional metabolome assay was further implemented to investigate the regulatory mechanism of iron on biofilm formation; we verified that siderophores mostly account for the transportation of iron into bacterial cells. Then, the bioavailable iron was recruited by bacterial cells to direct the levels of five functional metabolites (l-tryptophan, 5'-MTA, spermidine, CMP and L-leucine), which were identified as new effectors that directly regulate biofilm formation. Taken together, this study is the first to identify five functional metabolites to efficiently regulate biofilm formation, which can be targeted to tackle the harmful impacts associated with biofilm formation in different niches.}, } @article {pmid33453292, year = {2021}, author = {Nejadmansouri, M and Razmjooei, M and Safdarianghomsheh, R and Shad, E and Delvigne, F and Khalesi, M}, title = {Semi-continuous production of xanthan in biofilm reactor using Xanthomonas campestris.}, journal = {Journal of biotechnology}, volume = {328}, number = {}, pages = {1-11}, doi = {10.1016/j.jbiotec.2021.01.004}, pmid = {33453292}, issn = {1873-4863}, mesh = {Biofilms ; Fermentation ; Polysaccharides, Bacterial/metabolism ; *Xanthomonas campestris/metabolism ; }, abstract = {Semi-continuous production of xanthan gum using self-immobilized Xanthomonas campestris cells in biofilm reactors was studied. Fermentation was carried out using two different designs of biofilm reactor equipped with a) stainless-steel support (SSS) and b) polyethylene support (PES). Fermentation was performed in three cycles with refreshing the media at the beginning of each: cycle 1, 0-27 h; cycle 2, 27-54 h; and cycle 3, 54-78.5 h. Results showed that the glucose consumption and the pH reduction in the PES biofilm reactor was faster compared to the SSS biofilm reactor. Scanning electron microscopy showed that the SSS was capable to immobilize more cells during the growth of X. campestris. The maximum concentration of xanthan gum in the SSS biofilm reactor obtained after 27 h (3.47 ± 0.71 g/L), while the maximum concentration of xanthan in the PES biofilm reactor obtained after 78.5 h (3.21 ± 0.68 g/L). Thermal stability analysis of xanthan using differential scanning calorimetry showed the presence of two fractures attributed to dehydration and degradation of polymer. The thermogram represented both endothermal and exothermal behaviour of xanthan polymer. Furthermore, the functional groups and molecular structure of the xanthan produced in this study was evaluated using Fourier transform infrared spectrometry and also proton nuclear magnetic resonance. in addition, the surface tension of (0.2 %, w/v) xanthan gum solution was in a range of 52.16-56.5 mN/m. Rheological analysis of xanthan showed that the G' values were higher than the G″ in all frequencies demonstrating a relatively high elasticity of the produced xanthan gum.}, } @article {pmid33452316, year = {2021}, author = {Maszewska, A and Moryl, M and Wu, J and Liu, B and Feng, L and Rozalski, A}, title = {Amikacin and bacteriophage treatment modulates outer membrane proteins composition in Proteus mirabilis biofilm.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {1522}, pmid = {33452316}, issn = {2045-2322}, mesh = {Amikacin/metabolism/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacterial Infections ; Bacterial Outer Membrane Proteins/drug effects/metabolism ; Bacteriophages/pathogenicity/physiology ; Biofilms/drug effects ; Drug Resistance, Microbial/*drug effects ; Gram-Negative Bacteria/drug effects ; Membrane Proteins/drug effects/metabolism ; Proteus mirabilis/drug effects/*metabolism/virology ; }, abstract = {Modification of outer membrane proteins (OMPs) is the first line of Gram-negative bacteria defence against antimicrobials. Here we point to Proteus mirabilis OMPs and their role in antibiotic and phage resistance. Protein profiles of amikacin (AMKrsv), phage (Brsv) and amikacin/phage (AMK/Brsv) resistant variants of P. mirabilis were compared to that obtained for a wild strain. In resistant variants there were identified 14, 1, 5 overexpressed and 13, 5, 1 downregulated proteins for AMKrsv, Brsv and AMK/Brsv, respectively. Application of phages with amikacin led to reducing the number of up- and downregulated proteins compared to single antibiotic treatment. Proteins isolated in AMKrsv are involved in protein biosynthesis, transcription and signal transduction, which correspond to well-known mechanisms of bacteria resistance to aminoglycosides. In isolated OMPs several cytoplasmic proteins, important in antibiotic resistance, were identified, probably as a result of environmental stress, e.g. elongation factor Tu, asparaginyl-tRNA and aspartyl-tRNA synthetases. In Brsv there were identified: NusA and dynamin superfamily protein which could play a role in bacteriophage resistance. In the resistant variants proteins associated with resistance mechanisms occurring in biofilm, e.g. polyphosphate kinase, flagella basal body rod protein were detected. These results indicate proteins important in the development of P. mirabilis antibiofilm therapies.}, } @article {pmid33452271, year = {2021}, author = {Park, HY and Zoller, SD and Hegde, V and Sheppard, W and Burke, Z and Blumstein, G and Hamad, C and Sprague, M and Hoang, J and Smith, R and Romero Pastrana, F and Czupryna, J and Miller, LS and López-Álvarez, M and Bispo, M and van Oosten, M and van Dijl, JM and Francis, KP and Bernthal, NM}, title = {Comparison of two fluorescent probes in preclinical non-invasive imaging and image-guided debridement surgery of Staphylococcal biofilm implant infections.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {1622}, pmid = {33452271}, issn = {2045-2322}, support = {K08 AR069112/AR/NIAMS NIH HHS/United States ; T32 AR059033/AR/NIAMS NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms/drug effects/*growth & development ; Disease Models, Animal ; Fluorescent Dyes/*chemistry ; Mice ; Optical Imaging/*methods ; Prostheses and Implants ; Prosthesis-Related Infections/drug therapy/microbiology/pathology/*surgery ; Spinal Cord/*diagnostic imaging/surgery ; Staphylococcus aureus/*isolation & purification/physiology ; Surgery, Computer-Assisted ; Tomography, X-Ray Computed ; Vancomycin/pharmacology/therapeutic use ; }, abstract = {Implant-associated infections are challenging to diagnose and treat. Fluorescent probes have been heralded as a technologic advancement that can improve our ability to non-invasively identify infecting organisms, as well as guide the inexact procedure of surgical debridement. This study's purpose was to compare two fluorescent probes for their ability to localize Staphylococcus aureus biofilm infections on spinal implants utilizing noninvasive optical imaging, then assessing the broader applicability of the more successful probe in other infection animal models. This was followed by real-time, fluorescence image-guided surgery to facilitate debridement of infected tissue. The two probe candidates, a labelled antibiotic that targets peptidoglycan (Vanco-800CW), and the other, a labelled antibody targeting the immunodominant Staphylococcal antigen A (1D9-680), were injected into mice with spine implant infections. Mice were then imaged noninvasively with near infrared fluorescent imaging at wavelengths corresponding to the two probe candidates. Both probes localized to the infection, with the 1D9-680 probe showing greater fidelity over time. The 1D9-680 probe was then tested in mouse models of shoulder implant and allograft infection, demonstrating its broader applicability. Finally, an image-guided surgery system which superimposes fluorescent signals over analog, real-time, tissue images was employed to facilitate debridement of fluorescent-labelled bacteria.}, } @article {pmid33452019, year = {2021}, author = {Havlena, Z and Kieft, TL and Veni, G and Horrocks, RD and Jones, DS}, title = {Lighting Effects on the Development and Diversity of Photosynthetic Biofilm Communities in Carlsbad Cavern, New Mexico.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {6}, pages = {}, pmid = {33452019}, issn = {1098-5336}, mesh = {Bacteria/genetics ; Bacterial Physiological Phenomena ; *Biofilms ; Caves/*microbiology ; *Lighting ; Microbiota ; New Mexico ; Parks, Recreational ; Photosynthesis ; Phylogeny ; RNA, Ribosomal, 16S ; }, abstract = {Photosynthetic cave communities ("lampenflora") proliferate in Carlsbad Cavern and other show caves worldwide due to artificial lighting. These biofilms mar the esthetics and can degrade underlying cave surfaces. The National Park Service recently modernized the lighting in Carlsbad Cavern to a light-emitting diode (LED) system that allows adjustment of the color temperature and intensity. We hypothesized that lowering the color temperature would reduce photopigment development. We therefore assessed lampenflora responses to changes in lighting by monitoring photosynthetic communities over the course of a year. We measured photopigments using reflected-light spectrophotometric observations and analyzed microbial community composition with 16S and 18S rRNA gene amplicon sequencing. Reflected-light spectrophotometry revealed that photosynthetic biofilm development is affected by lighting intensity, color temperature, substrate type, and cleaning of the substrate. Gene sequencing showed that the most abundant phototrophs were Cyanobacteria and members of the algal phyla Chlorophyta and Ochrophyta At the end of the study, visible growth of lampenflora was seen at all sites. At sites that had no established biofilm at the start of the study period, Cyanobacteria became abundant and outpaced an increase in eukaryotic algae. Microbial diversity also increased over time at these sites, suggesting a possible pattern of early colonization and succession. Bacterial community structure showed significant effects of all variables: color temperature, light intensity, substrate type, site, and previous cleaning of the substrate. These findings provide fundamental information that can inform management practices; they suggest that altering lighting conditions alone may be insufficient to prevent lampenflora growth.IMPORTANCE Artificial lighting in caves visited by tourists ("show caves") can stimulate photosynthetic algae and cyanobacteria, called "lampenflora," which are unsightly and damage speleothems and other cave surfaces. The most common mitigation strategy employs bleach, but altering intensities and wavelengths of light might be effective and less harsh. Carlsbad Cavern in New Mexico, a U.S. National Park and UNESCO World Heritage Site, has visible lampenflora despite adjustment of LED lamps to decrease the energetic blue light. This study characterized the lampenflora communities and tested the effects of color temperature, light intensity, rock or sediment texture, and time on lampenflora development. DNA amplicon sequence data show a variety of algae and cyanobacteria and also heterotrophic bacteria. This study reveals microbial dynamics during colonization of artificially lit surfaces and indicates that while lowering the color temperature may have an effect, management of lampenflora will likely require additional chemical or UV treatment.}, } @article {pmid33450684, year = {2021}, author = {Reichert, G and Hilgert, S and Alexander, J and Rodrigues de Azevedo, JC and Morck, T and Fuchs, S and Schwartz, T}, title = {Determination of antibiotic resistance genes in a WWTP-impacted river in surface water, sediment, and biofilm: Influence of seasonality and water quality.}, journal = {The Science of the total environment}, volume = {768}, number = {}, pages = {144526}, doi = {10.1016/j.scitotenv.2020.144526}, pmid = {33450684}, issn = {1879-1026}, mesh = {*Anti-Bacterial Agents/analysis ; Biofilms ; Drug Resistance, Microbial/genetics ; Genes, Bacterial ; Germany ; Wastewater ; Water ; *Water Purification ; Water Quality ; }, abstract = {Many pathogenic bacteria are adapted to live in aquatic habitats, which makes rivers possible sources and spread pathways of antibiotic resistance, since they usually receive effluents from wastewater treatment plants (WWTP), possibly containing antibiotic residues and also antibiotic-resistant bacteria. This study investigates different monitoring strategies to identify the occurrence of antibiotic-resistant bacteria in rivers. We analyzed the presence of 13 antibiotic resistance genes (ARGs) and seven gene markers for facultative pathogenic bacteria (FPB) with qPCR in sampling sites upstream and downstream of a small WWTP in Southern Germany. Five sampling campaigns were conducted from February to June 2019. Surface water, sediment, and biofilm samples were analyzed. The biofilm was collected from an artificial sampler placed in the river. blaTEM, ermB, tetM, and sul1 genes were detected in all samples analyzed. The results showed there was a previous background in the river, but the WWTP and the water quality of the river influenced the concentration and occurrence of ARGs and FPB. Genes representing resistance against strong or last-resort antibiotics, such as mecA, blaCMY-2, blaKPC-3, and mcr-1, and multidrug resistance were also detected, mainly in samples collected downstream of the WWTP. Downstream of the WWTP, the occurrence of ARG and FPB correlated with ammoniacal nitrogen, while upstream of the WWTP correlated with turbidity, suspended solids, and seasonal factors such as UVA radiation and the presence of macrophytes. Biofilm samples presented higher abundances of ARGs and FPB. The biofilm sampler was efficient and allowed to collect biofilms from specific periods, which helped to identify seasonal patterns.}, } @article {pmid33450228, year = {2021}, author = {Irmscher, T and Roske, Y and Gayk, I and Dunsing, V and Chiantia, S and Heinemann, U and Barbirz, S}, title = {Pantoea stewartii WceF is a glycan biofilm-modifying enzyme with a bacteriophage tailspike-like fold.}, journal = {The Journal of biological chemistry}, volume = {296}, number = {}, pages = {100286}, pmid = {33450228}, issn = {1083-351X}, mesh = {Bacterial Proteins/*chemistry/genetics/metabolism ; Bacteriophages/chemistry/enzymology ; Binding Sites ; Biofilms/*growth & development ; Carbohydrate Sequence ; Cloning, Molecular ; Crystallography, X-Ray ; Escherichia coli/genetics/metabolism ; Gene Expression ; Genetic Vectors/chemistry/metabolism ; Glycoside Hydrolases/*chemistry/genetics/metabolism ; Models, Molecular ; Oligosaccharides/chemistry/metabolism ; Pantoea/*enzymology/genetics ; Plants/microbiology ; Polysaccharides, Bacterial/*chemistry/metabolism ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Protein Multimerization ; Recombinant Proteins/chemistry/genetics/metabolism ; Structural Homology, Protein ; Viral Tail Proteins/*chemistry/genetics/metabolism ; }, abstract = {Pathogenic microorganisms often reside in glycan-based biofilms. Concentration and chain length distribution of these mostly anionic exopolysaccharides (EPS) determine the overall biophysical properties of a biofilm and result in a highly viscous environment. Bacterial communities regulate this biofilm state via intracellular small-molecule signaling to initiate EPS synthesis. Reorganization or degradation of this glycan matrix, however, requires the action of extracellular glycosidases. So far, these were mainly described for bacteriophages that must degrade biofilms for gaining access to host bacteria. The plant pathogen Pantoea stewartii (P. stewartii) encodes the protein WceF within its EPS synthesis cluster. WceF has homologs in various biofilm forming plant pathogens of the Erwinia family. In this work, we show that WceF is a glycosidase active on stewartan, the main P. stewartii EPS biofilm component. WceF has remarkable structural similarity with bacteriophage tailspike proteins (TSPs). Crystal structure analysis showed a native trimer of right-handed parallel β-helices. Despite its similar fold, WceF lacks the high stability found in bacteriophage TSPs. WceF is a stewartan hydrolase and produces oligosaccharides, corresponding to single stewartan repeat units. However, compared with a stewartan-specific glycan hydrolase of bacteriophage origin, WceF showed lectin-like autoagglutination with stewartan, resulting in notably slower EPS cleavage velocities. This emphasizes that the bacterial enzyme WceF has a role in P. stewartii biofilm glycan matrix reorganization clearly different from that of a bacteriophage exopolysaccharide depolymerase.}, } @article {pmid33448498, year = {2021}, author = {Steinchen, W and Ahmad, S and Valentini, M and Eilers, K and Majkini, M and Altegoer, F and Lechner, M and Filloux, A and Whitney, JC and Bange, G}, title = {Dual role of a (p)ppGpp- and (p)ppApp-degrading enzyme in biofilm formation and interbacterial antagonism.}, journal = {Molecular microbiology}, volume = {115}, number = {6}, pages = {1339-1356}, doi = {10.1111/mmi.14684}, pmid = {33448498}, issn = {1365-2958}, support = {MR/P028225/1/MRC_/Medical Research Council/United Kingdom ; PJT-156129//CIHR/Canada ; }, mesh = {Adenine Nucleotides/*metabolism ; Antibiosis/*physiology ; Biofilms/growth & development ; Gene Expression Regulation, Bacterial/genetics ; Guanosine Pentaphosphate/*metabolism ; N-Glycosyl Hydrolases/*metabolism ; Pseudomonas aeruginosa/growth & development/*metabolism ; Type VI Secretion Systems/*metabolism ; }, abstract = {The guanosine nucleotide-based second messengers ppGpp and pppGpp (collectively: (p)ppGpp) enable adaptation of microorganisms to environmental changes and stress conditions. In contrast, the closely related adenosine nucleotides (p)ppApp are involved in type VI secretion system (T6SS)-mediated killing during bacterial competition. Long RelA-SpoT Homolog (RSH) enzymes regulate synthesis and degradation of (p)ppGpp (and potentially also (p)ppApp) through their synthetase and hydrolase domains, respectively. Small alarmone hydrolases (SAH) that consist of only a hydrolase domain are found in a variety of bacterial species, including the opportunistic human pathogen Pseudomonas aeruginosa. Here, we present the structure and mechanism of P. aeruginosa SAH showing that the enzyme promiscuously hydrolyses (p)ppGpp and (p)ppApp in a strictly manganese-dependent manner. While being dispensable for P. aeruginosa growth or swimming, swarming, and twitching motilities, its enzymatic activity is required for biofilm formation. Moreover, (p)ppApp-degradation by SAH provides protection against the T6SS (p)ppApp synthetase effector Tas1, suggesting that SAH enzymes can also serve as defense proteins during interbacterial competition.}, } @article {pmid33447822, year = {2020}, author = {Fleming, D and Redman, W and Welch, GS and Mdluli, NV and Rouchon, CN and Frank, KL and Rumbaugh, KP}, title = {Utilizing glycoside hydrolases to improve the quantitation and visualization of biofilm bacteria.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100037}, pmid = {33447822}, issn = {2590-2075}, support = {R01 AI141961/AI/NIAID NIH HHS/United States ; R21 AI137462/AI/NIAID NIH HHS/United States ; }, abstract = {The complexity of microbial biofilms offers several challenges to the use of traditional means of microbial research. In particular, it can be difficult to calculate accurate numbers of biofilm bacteria, because even after thorough homogenization or sonication, small pieces of the biofilm remain, which contain numerous bacterial cells and result in inaccurately low colony forming units (CFU). In addition, imaging of infected tissue ex vivo often results in a disparity between the CFU and the number of bacterial cells observed under the microscope. We hypothesized that this phenomenon is due to the biofilm extracellular polymeric substance decreasing the accessibility of stains and antibodies to the embedded bacterial cells. In this study, we describe incorporating EPS-degrading glycoside hydrolases for CFU determination to obtain a more accurate estimation of the viable cells and for immunohistochemistry to disrupt the biofilm matrix and increase primary antibody binding to the bacterial cells.}, } @article {pmid33447819, year = {2020}, author = {da Silva, GOA and Pennafirme, S and da Costa Pereira, D and Waite, CCC and Lopes, RT and Lima, ICB and Crapez, MAC}, title = {Monitoring of bacterial community structure and growth: An alternative tool for biofilm microanalysis.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100034}, pmid = {33447819}, issn = {2590-2075}, abstract = {Microorganisms, such as bacteria, tend to aggregate and grow on surfaces, secreting extracellular polymeric substances (EPS), forming biofilms. Biofilm formation is a life strategy, because through it microorganisms can create their own microhabitats. Whether for remediation of pollutants or application in the biomedical field, several methodological approaches are necessary for a more accurate analysis of the role and potential use of bacterial biofilms. The use of computerized microtomography to monitor biofilm growth appears to be an advantageous tool due to its non-destructive character and its ability to render 2D and 3D visualization of the samples. In this study, we used several techniques such as analysis of microbiological parameters and biopolymer concentrations to corroborate porosity quantified by 2D and 3D imaging. Quantification of the porosity of samples by microtomography was verified by increased enzymatic activity and, consequently, higher EPS biopolymer synthesis to form biofilm, indicating growth of the biofilm over 96 h. Our interdisciplinary approach provides a better understanding of biofilm growth, enabling integrated use of these techniques as an important tool in bioremediation studies of environments impacted by pollutants.}, } @article {pmid33447818, year = {2020}, author = {Maale, GE and Eager, JJ and Srinivasaraghavan, A and Mohammadi, DK and Kennard, N}, title = {The evolution from the two stage to the one stage procedure for biofilm based periprosthetic joint infections (PJI).}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100033}, pmid = {33447818}, issn = {2590-2075}, abstract = {A definitive consensus on the optimal limb salvage protocol for infected total joints does not currently exist. Popular, is the two-stage revision which calls for the use of an antibiotic loaded spacer followed by a delayed exchange. Our question is whether single-stage revisions for biofilm based infected arthroplasties results in comparable or possibly better patient outcomes as compared to those reported for two-stage revisions. We retrospectively reviewed 500 cases of one-stage revisions for periprosthetic joint infections (PJI) using dual setup with radical debridement, definitive reconstruction with antibiotic loaded cement and implantation of antibiotic calcium sulfate pellets between the years 2005-2017. The revisions included 351 total knees, 122 hips, 2 hip-femur-knees, 13 shoulders, 10 elbows, and 2 shoulder-humerus-elbows. The patient population had a mean follow-up of 60 months (range: 24 months-14 years) and mean patient age of 61 years old, consisting of 250 males and 250 females. Patient comorbidities were reviewed, classified using McPherson's staging for PJIs, and compared to the Cierny & Mader classification system. Successful treatment was defined as a joint without recurrence of infection, for a minimum of 2 years, and limb preservation. Based on our findings, one-stage revision of PJIs demonstrates at least as good an infection eradication rate as two-stage revision: 88% vs 85% respectively.}, } @article {pmid33447817, year = {2020}, author = {Williams, DL and Kawaguchi, B and Taylor, NB and Allyn, G and Badham, MA and Rogers, JC and Peterson, BR and Sebahar, PR and Haussener, TJ and Reddy, HRK and Isaacson, BM and Pasquina, PF and Looper, RE}, title = {In vivo efficacy of a unique first-in-class antibiofilm antibiotic for biofilm-related wound infections caused by Acinetobacter baumannii.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100032}, pmid = {33447817}, issn = {2590-2075}, abstract = {Wounds complicated by biofilms challenge even the best clinical care and can delay a return to duty for service members. A major component of treatment in wounded warriors includes infected wound management. Yet, all antibiotic therapy options have been optimized against planktonic bacteria, leaving an important gap in biofilm-related wound care. We tested the efficacy of a unique compound (CZ-01179) specifically synthesized to eradicate biofilms. CZ-01179 was formulated as the active agent in a hydrogel, and tested in vitro and in vivo in a pig excision wound model for its ability to treat and prevent biofilm-related wound infection caused by Acinetobacter baumannii. Data indicated that compared to a clinical standard-silver sulfadiazine-CZ-01179 was much more effective at eradicating biofilms of A. baumannii in vitro and up to 6 days faster at eradicating biofilms in vivo. CZ-01179 belongs to a broader class of newly-synthesized antibiofilm agents (referred to as CZ compounds) with reduced risk of resistance development, specific efficacy against biofilms, and promising formulation potential for clinical applications. Given its broad spectrum and biofilm-specific nature, CZ-01179 gel may be a promising agent to increase the pipeline of products to treat and prevent biofilm-related wound infections.}, } @article {pmid33447816, year = {2020}, author = {Vandeplassche, E and Sass, A and Ostyn, L and Burmølle, M and Kragh, KN and Bjarnsholt, T and Coenye, T and Crabbé, A}, title = {Antibiotic susceptibility of cystic fibrosis lung microbiome members in a multispecies biofilm.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100031}, pmid = {33447816}, issn = {2590-2075}, abstract = {The lungs of cystic fibrosis (CF) patients are often chronically colonized by multiple microbial species that can form biofilms, including the major CF pathogen Pseudomonas aeruginosa. Herewith, lower microbial diversity in CF airways is typically associated with worse health outcomes. In an attempt to treat CF lung infections patients are frequently exposed to antibiotics, which may affect microbial diversity. This study aimed at understanding if common antibiotics that target P. aeruginosa influence microbial diversity. To this end, a microaerophilic multispecies biofilm model of frequently co-isolated members of the CF lung microbiome (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus anginosus, Achromobacter xylosoxidans, Rothia mucilaginosa, and Gemella haemolysans) was exposed to antipseudomonal antibiotics. We found that antibiotics that affected several dominant species (i.e. ceftazidime, tobramycin) resulted in higher species evenness compared to colistin, which is only active against P. aeruginosa. Furthermore, susceptibility of individual species in the multispecies biofilm following antibiotic treatment was compared to that of the respective single-species biofilms, showing no differences. Adding three anaerobic species (Prevotella melaninogenica, Veillonella parvula, and Fusobacterium nucleatum) to the multispecies biofilm did not influence antibiotic susceptibility. In conclusion, our study demonstrates antibiotic-dependent effects on microbial community diversity of multispecies biofilms comprised of CF microbiome members.}, } @article {pmid33447815, year = {2020}, author = {Sjöberg, S and Stairs, C and Allard, B and Hallberg, R and Homa, F and Martin, T and Ettema, TJG and Dupraz, C}, title = {Bubble biofilm: Bacterial colonization of air-air interface.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100030}, pmid = {33447815}, issn = {2590-2075}, support = {310039/ERC_/European Research Council/International ; }, abstract = {Microbial mats or biofilms are known to colonize a wide range of substrates in aquatic environments. These dense benthic communities efficiently recycle nutrients and often exhibit high tolerance to environmental stressors, characteristics that enable them to inhabit harsh ecological niches. In some special cases, floating biofilms form at the air-water interface residing on top of a hydrophobic microlayer. Here, we describe biofilms that reside at the air-air interface by forming gas bubbles (bubble biofilms) in the former Ytterby mine, Sweden. The bubbles are built by micrometer thick membrane-like biofilm that holds enough water to sustain microbial activity. Molecular identification shows that the biofilm communities are dominated by the neuston bacterium Nevskia. Gas bubbles contain mostly air with a slightly elevated concentration of carbon dioxide. Biofilm formation and development was monitored in situ using a time-lapse camera over one year, taking one image every second hour. The bubbles were stable over long periods of time (weeks, even months) and gas build-up occurred in pulses as if the bedrock suddenly exhaled. The result was however not a passive inflation of a dying biofilm becoming more fragile with time (as a result of overstretching of the organic material). To the contrary, microbial growth lead to a more robust, hydrophobic bubble biofilm that kept the bubbles inflated for extended periods (several weeks, and in some cases even months).}, } @article {pmid33447814, year = {2020}, author = {Hiebner, DW and Barros, C and Quinn, L and Vitale, S and Casey, E}, title = {Surface functionalization-dependent localization and affinity of SiO2 nanoparticles within the biofilm EPS matrix.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100029}, pmid = {33447814}, issn = {2590-2075}, abstract = {The contribution of the biofilm extracellular polymeric substance (EPS) matrix to reduced antimicrobial susceptibility in biofilms is widely recognised. As such, the direct targeting of the EPS matrix is a promising biofilm control strategy that allows for the disruption of the matrix, thereby allowing a subsequent increase in susceptibility to antimicrobial agents. To this end, surface-functionalized nanoparticles (NPs) have received considerable attention. However, the fundamental understanding of the interactions occurring between engineered NPs and the biofilm EPS matrix has not yet been fully elucidated. An insight into the underlying mechanisms involved when a NP interacts with the EPS matrix will aid in the design of more efficient NPs for biofilm control. Here we demonstrate the use of highly specific fluorescent probes in confocal laser scanning microscopy (CLSM) to illustrate the distribution of EPS macromolecules within the biofilm. Thereafter, a three-dimensional (3D) colocalization analysis was used to assess the affinity of differently functionalized silica NPs (SiNPs) and EPS macromolecules from Pseudomonas fluorescens biofilms. Results show that both the charge and surface functional groups of SiNPs dramatically affected the extent to which SiNPs interacted and localized with EPS macromolecules, including proteins, polysaccharides and DNA. Hypotheses are also presented about the possible physicochemical interactions which may be dominant in EPS matrix-NP interactions. This research not only develops an innovative CLSM-based methodology for elucidating biofilm-nanoparticle interactions but also provides a platform on which to build more efficient NP systems for biofilm control.}, } @article {pmid33447813, year = {2020}, author = {Rumbaugh, KP}, title = {How well are we translating biofilm research from bench-side to bedside?.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100028}, pmid = {33447813}, issn = {2590-2075}, support = {R21 AI137462/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilms are responsible for more than 80% of all chronic infections and represent an enormous medical challenge. In order to meet this challenge, translation research on anti-biofilm approaches is desperately needed. While biofilm research has grown exponentially over the last three decades and provided important details about the mechanisms involved in initiating, maintaining and disrupting bacterial communities, how much of this basic science knowledge has resulted in new therapeutic approaches? In this perspective article biofilm publications, patents, clinical trials and companies were surveyed to ascertain where we stand in translating biofilm research into new strategies to treat and prevent biofilm-associated infections. Overall, the survey data obtained indicate that anti-biofilm research makes up a very small percentage of the total biofilm literature, and the number of patents and clinical studies for anti-biofilm agents is relatively small. However, the forecast for the future of anti-biofilm therapeutics looks promising. Publications on translational studies are trending up and there are a large number of companies selling products marketed to fight biofilm, indicating that there is a significant commercial interest. Researchers can aid in the translational effort by collaborating with clinicians and industry to design and execute clinically relevant pre-clinical studies, which will result in more agents successfully completing clinical studies and entering the market.}, } @article {pmid33447812, year = {2020}, author = {Wille, J and Coenye, T}, title = {Biofilm dispersion: The key to biofilm eradication or opening Pandora's box?.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100027}, pmid = {33447812}, issn = {2590-2075}, abstract = {Biofilms are extremely difficult to eradicate due to their decreased antibiotic susceptibility. Inducing biofilm dispersion could be a potential strategy to help combat biofilm-related infections. Mechanisms of biofilm dispersion can basically be divided into two groups, i.e. active and passive dispersion. Active dispersion depends on a decrease in the intracellular c-di-GMP levels, leading to the production of enzymes that degrade the biofilm matrix and promote dispersion. In contrast, passive dispersion relies on triggers that directly release cells from the biofilm. In the present review, several active and passive dispersion strategies are discussed. In addition, the disadvantages and possible consequences of using dispersion as a treatment approach for biofilm-related infections are also reviewed.}, } @article {pmid33447811, year = {2020}, author = {Zea, L and McLean, RJC and Rook, TA and Angle, G and Carter, DL and Delegard, A and Denvir, A and Gerlach, R and Gorti, S and McIlwaine, D and Nur, M and Peyton, BM and Stewart, PS and Sturman, P and Velez Justiniano, YA}, title = {Potential biofilm control strategies for extended spaceflight missions.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100026}, pmid = {33447811}, issn = {2590-2075}, support = {80NSSC17K0036/ImNASA/Intramural NASA/United States ; }, abstract = {Biofilms, surface-adherent microbial communities, are associated with microbial fouling and corrosion in terrestrial water-distribution systems. Biofilms are also present in human spaceflight, particularly in the Water Recovery System (WRS) on the International Space Station (ISS). The WRS is comprised of the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA) which together recycles wastewater from human urine and recovered humidity from the ISS atmosphere. These wastewaters and various process streams are continually inoculated with microorganisms primarily arising from the space crew microbiome. Biofilm-related fouling has been encountered and addressed in spacecraft in low Earth orbit, including ISS and the Russian Mir Space Station. However, planned future missions beyond low Earth orbit to the Moon and Mars present additional challenges, as resupplying spare parts or support materials would be impractical and the mission timeline would be in the order of years in the case of a mission to Mars. In addition, future missions are expected to include a period of dormancy in which the WRS would be unused for an extended duration. The concepts developed in this review arose from a workshop including NASA personnel and representatives with biofilm expertise from a wide range of industrial and academic backgrounds. Here, we address current strategies that are employed on Earth for biofilm control, including antifouling coatings and biocides and mechanisms for mitigating biofilm growth and damage. These ideas are presented in the context of their applicability to spaceflight and identify proposed new topics of biofilm control that need to be addressed in order to facilitate future extended, crewed, spaceflight missions.}, } @article {pmid33447810, year = {2020}, author = {Cornell, WC and Zhang, Y and Bendebury, A and Hartel, AJW and Shepard, KL and Dietrich, LEP}, title = {Phenazine oxidation by a distal electrode modulates biofilm morphogenesis.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100025}, pmid = {33447810}, issn = {2590-2075}, support = {R01 AI103369/AI/NIAID NIH HHS/United States ; }, abstract = {Microbes living in biofilms, dense assemblages of cells, experience limitation for resources such as oxygen when cellular consumption outpaces diffusion. The pathogenic bacterium Pseudomonas aeruginosa has strategies for coping with hypoxia that support cellular redox balancing in biofilms; these include (1) increasing access to oxygen by forming wrinkles in the biofilm surface and (2) electrochemically reducing endogenous compounds called phenazines, which can shuttle electrons to oxidants available at a distance. Phenazine-mediated extracellular electron transfer (EET) has been shown to support survival for P. aeruginosa cells in anoxic liquid cultures, but the physiological relevance of EET over a distance for P. aeruginosa biofilms has remained unconfirmed. Here, we use a custom-built electrochemistry setup to show that phenazine-mediated electron transfer at a distance inhibits wrinkle formation in P. aeruginosa biofilms. This result demonstrates that phenazine-dependent EET to a distal oxidant affects biofilm morphogenesis.}, } @article {pmid33447809, year = {2020}, author = {Schinner, S and Engelhardt, F and Preusse, M and Thöming, JG and Tomasch, J and Häussler, S}, title = {Genetic determinants of Pseudomonas aeruginosa fitness during biofilm growth.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100023}, pmid = {33447809}, issn = {2590-2075}, abstract = {Pseudomonas aeruginosa is an environmental bacterium and an opportunistic human pathogen. It is also a well-established model organism to study bacterial adaptation to stressful conditions, such as those encountered during an infection process in the human host. Advancing knowledge on P. aeruginosa adaptation to biofilm growth conditions is bound to reveal novel strategies and targets for the treatment of chronic biofilm-associated infections. Here, we generated transposon insertion libraries in three P. aeruginosa strain backgrounds and determined the relative frequency of each insertion following biofilm growth using transposon sequencing. We demonstrate that in general the SOS response, several tRNA modifying enzymes as well as adaptation to microaerophilic growth conditions play a key role in bacterial survival under biofilm growth conditions. On the other hand, presence of genes involved in motility and PQS signaling were less important during biofilm growth. Several mutants exhibiting transposon insertions in genes detected in our screen were validated for their biofilm growth capabilities and biofilm specific transcriptional responses using independently generated transposon mutants. Our results provide new insights into P. aeruginosa adaptation to biofilm growth conditions. The detection of previously unknown determinants of biofilm survival supports the use of transposon insertion sequencing as a global genomic technology for understanding the establishment of difficult to treat biofilm-associated infections.}, } @article {pmid33447808, year = {2020}, author = {Lories, B and Belpaire, TER and Yssel, A and Ramon, H and Steenackers, HP}, title = {Agaric acid reduces Salmonella biofilm formation by inhibiting flagellar motility.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100022}, pmid = {33447808}, issn = {2590-2075}, abstract = {Salmonella biofilms are a common cause of contaminations in the food or feed industry. In a screening for novel compounds to combat biofilm-associated foodborne outbreaks, we identified agaric acid as a Salmonella Typhimurium biofilm inhibitor that does not affect planktonic growth. Importantly, the remaining biofilm cells after preventive treatment with agaric acid were significantly more sensitive to the common disinfectant hydrogen peroxide. Screening of a GFP-promoter fusion library of biofilm related genes revealed that agaric acid downregulates the transcription of genes responsible for flagellar motility. Concurrently, swimming motility was completely abrogated in the presence of agaric acid, indicating that biofilm inhibition occurs via interference with the motility phenotype. Moreover, agaric acid also reduced biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Agaric acid thus shows potential as an anti-virulence compound that inhibits both motility and biofilm formation.}, } @article {pmid33447807, year = {2020}, author = {Thérien, M and Kiesewalter, HT and Auria, E and Charron-Lamoureux, V and Wibowo, M and Maróti, G and Kovács, ÁT and Beauregard, PB}, title = {Surfactin production is not essential for pellicle and root-associated biofilm development of Bacillus subtilis.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100021}, pmid = {33447807}, issn = {2590-2075}, abstract = {Secondary metabolites have an important impact on the biocontrol potential of soil-derived microbes. In addition, various microbe-produced chemicals have been suggested to impact the development and phenotypic differentiation of bacteria, including biofilms. The non-ribosomal synthesized lipopeptide of Bacillus subtilis, surfactin, has been described to impact the plant promoting capacity of the bacterium. Here, we investigated the impact of surfactin production on biofilm formation of B. subtilis using the laboratory model systems; pellicle formation at the air-medium interface and architecturally complex colony development, in addition to plant root-associated biofilms. We found that the production of surfactin by B. subtilis is not essential for pellicle biofilm formation neither in the well-studied strain, NCIB 3610, nor in the newly isolated environmental strains, but lack of surfactin reduces colony expansion. Further, plant root colonization was comparable both in the presence or absence of surfactin synthesis. Our results suggest that surfactin-related biocontrol and plant promotion in B. subtilis strains are independent of biofilm formation.}, } @article {pmid33446592, year = {2021}, author = {Arif, S and Nacke, H and Hoppert, M}, title = {Metagenome-Assembled Genome Sequences of a Biofilm Derived from Marsberg Copper Mine.}, journal = {Microbiology resource announcements}, volume = {10}, number = {2}, pages = {}, pmid = {33446592}, issn = {2576-098X}, abstract = {We sequenced the metagenome of a biofilm collected near a leachate stream of the Marsberg copper mine (Germany) and reconstructed eight metagenome-assembled genomes. These genomes yield copper resistance through Cu(I) oxidation via multiple copper oxidases and extrusion through copper-exporting P-type ATPases.}, } @article {pmid33445707, year = {2021}, author = {Relucenti, M and Familiari, G and Donfrancesco, O and Taurino, M and Li, X and Chen, R and Artini, M and Papa, R and Selan, L}, title = {Microscopy Methods for Biofilm Imaging: Focus on SEM and VP-SEM Pros and Cons.}, journal = {Biology}, volume = {10}, number = {1}, pages = {}, pmid = {33445707}, issn = {2079-7737}, support = {PGR01023//Grant from the Italian Ministry of Foreign Affairs and International Cooperation PGR01023./ ; }, abstract = {Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO4), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.}, } @article {pmid34122926, year = {2020}, author = {Wang, H and Christiansen, DE and Mehraeen, S and Cheng, G}, title = {Winning the fight against biofilms: the first six-month study showing no biofilm formation on zwitterionic polyurethanes.}, journal = {Chemical science}, volume = {11}, number = {18}, pages = {4709-4721}, pmid = {34122926}, issn = {2041-6520}, abstract = {Biofilms have been a long-standing challenge for healthcare, water transport, and many other industries. They lead to bacterial growth and infections in animals, food products, and humans, cause premature removal of the implanted materials or devices from patients, and facilitate fouling and corrosion of metals. Despite some published and patented methods on minimizing the effects of biofilms for a short period (less than two weeks), there exists no successful means to mitigate or prevent the long-term formation of biofilms. It is even more challenging to integrate critical anti-fouling properties with other needed physical and chemical properties for a range of applications. In this study, we developed a novel approach for combining incompatible, highly polar anti-fouling groups with less polar, mechanically modifying groups into one material. A multifunctional carboxybetaine precursor was designed and introduced into polyurethane. The carboxybetaine precursors undergo rapid, self-catalyzed hydrolysis at the water/material interface and provide critical anti-fouling properties that lead to undetectable bacterial attachment and zero biofilm formation after six months of constant exposure to Pseudomonas aeruginosa and Staphylococcus epidermidis under the static condition in a nutrient-rich medium. This zwitterionic polyurethane is the first material to demonstrate both critical anti-biofilm properties and tunable mechanical properties and directly validates the unproven anti-fouling strategy and hypothesis for biofilm formation prevention. This approach of designing 'multitasking materials' will be useful for the development of next generation anti-fouling materials for a variety of applications.}, } @article {pmid34138282, year = {2020}, author = {Zhang, Y and Xie, X and Ma, W and Zhan, Y and Mao, C and Shao, X and Lin, Y}, title = {Multi-targeted Antisense Oligonucleotide Delivery by a Framework Nucleic Acid for Inhibiting Biofilm Formation and Virulence.}, journal = {Nano-micro letters}, volume = {12}, number = {1}, pages = {74}, pmid = {34138282}, issn = {2150-5551}, abstract = {Biofilm formation is responsible for numerous chronic infections and represents a serious health challenge. Bacteria and the extracellular polysaccharides (EPS) cause biofilms to become adherent, toxic, resistant to antibiotics, and ultimately difficult to remove. Inhibition of EPS synthesis can prevent the formation of bacterial biofilms, reduce their robustness, and promote removal. Here, we have developed a framework nucleic acid delivery system with a tetrahedral configuration. It can easily access bacterial cells and functions by delivering antisense oligonucleotides that target specific genes. We designed antisense oligonucleotide sequences with multiple targets based on conserved regions of the VicK protein-binding site. Once delivered to bacterial cells, they significantly decreased EPS synthesis and biofilm thickness. Compared to existing approaches, this system is highly efficacious because it simultaneously reduces the expression of all targeted genes (gtfBCD, gbpB, ftf). We demonstrate a novel nucleic acid-based nanomaterial with multi-targeted inhibition that has great potential for the treatment of chronic infections caused by biofilms.}, } @article {pmid34056561, year = {2020}, author = {Kearns, KL and Boyd, JD and Grady, ME}, title = {Biofilm rupture by laser-induced stress waves increases with loading amplitude, independent of location.}, journal = {ACS applied bio materials}, volume = {3}, number = {3}, pages = {1426-1433}, pmid = {34056561}, issn = {2576-6422}, support = {P30 GM110788/GM/NIGMS NIH HHS/United States ; }, abstract = {Integral to the production of safe and biocompatible medical devices is to determine the interfacial properties that affect or control strong biofilm adhesion. The laser spallation technique has recently emerged as an advantageous method to quantify biofilm adhesion across candidate biomedical surfaces. However, there is a possibility that membrane tension is a factor that contributes to the stress required to separate biofilm and substrate. In that case, the stress amplitude, controlled by laser fluence, that initiates biofilm rupture would vary systematically with location on the biofilm. Film rupture, also known as spallation, occurs when film material is ejected during stress wave loading. In order to determine effects of membrane tension on the laser spallation process, we present a protocol that measures spall size with increasing laser fluence (variable fluence) and with respect to distance from the biofilm centroid (iso-fluence). Streptococcus mutans biofilms on titanium substrates serve as our model system. A total of 185 biofilm loading locations are analyzed in this study. We demonstrate that biofilm spall size increases monotonically with laser fluence and apply our procedure to failure of non-biological films. In iso-fluence experiments, no correlation is found between biofilm spall size and loading location, thus providing evidence that membrane tension does not play a dominant role in biofilm adhesion measurements. We recommend our procedure as a straightforward method to determine membrane effects in the measurement of adhesion of biological films on substrate surfaces via the laser spallation technique.}, } @article {pmid33658891, year = {2020}, author = {Nędzi-Góra, M and Górska, R and Górski, B}, title = {Is the progression rate of periodontitis related to subgingival biofilm composition or gingival crevicular fluid IL-1β and MMP-8 concentrations?.}, journal = {Central-European journal of immunology}, volume = {45}, number = {4}, pages = {425-432}, pmid = {33658891}, issn = {1426-3912}, abstract = {AIM OF THE STUDY: To analyze the composition of subgingival biofilm and to assess the concentration of IL-1 and MMP-8 in gingival crevicular fluid (GCF) from deep periodontal pockets in patients with severe periodontitis to determine whether the presence of specific microbial species or the severity of the host's immune response can be helpful in assessing the dynamics of disease.

MATERIAL AND METHODS: The study included 30 individuals with periodontitis Grade B and 19 subjects with periodontitis Grade C. Quantitative and qualitative microbiological analysis of flora in pockets ≥ 7 mm was performed for the presence of selected periopathogens of the orange, red complex and Aggregatibacter actinomycetemcomitans using real-time PCR. The concentrations of IL-1 and MMP-8 in GCF were evaluated with the ELISA method.

RESULTS: There were no differences in the composition of the subgingival biofilm depending on the diagnosis. The concentration of MMP-8 in GCF was significantly higher in periodontitis Grade C than in periodontitis Grade B (61 ng/µl and 37 ng/µl respectively, p = 0.039). The concentration of IL-1β was similar in both groups. No significant correlations were observed between the occurrence of individual periopathogens and concentrations of MMP-8 and IL-1β depending on the diagnosis.

CONCLUSIONS: Periodontitis grade may not be distinguished according to microbial analysis of subgingival biofilm or to concentration of IL-1β in GCF. On the other hand, higher concentrations of MMP-9 in GCF from deep pockets may be helpful in detecting subjects particularly prone to occurrence and rapid progress of periodontitis.}, } @article {pmid33447799, year = {2020}, author = {Coenye, T and Kjellerup, B and Stoodley, P and Bjarnsholt, T and , }, title = {The future of biofilm research - Report on the '2019 Biofilm Bash'.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100012}, pmid = {33447799}, issn = {2590-2075}, abstract = {In May 2019, 29 scientists with expertise in various subdisciplines of biofilm research got together in Leavenworth (WA, USA) at an event designated as the '2019 Biofilm Bash'. The goal of this informal two-day meeting was first to identify gaps in our knowledge, and then to come up with ways how the biofilm community can fill these gaps. The meeting was organized around six questions that covered the most important items brought forward by the organizers and participants. The outcome of these discussions is summarized in the present paper. We are aware that these views represent a small subset of our field, and that inevitably we will have inadvertently overlooked important developing research areas and ideas. We are nevertheless hopeful that this report will stimulate discussions and help create new ways of how we can advance our field.}, } @article {pmid33447803, year = {2020}, author = {Gloag, ES and Fabbri, S and Wozniak, DJ and Stoodley, P}, title = {Biofilm mechanics: Implications in infection and survival.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100017}, pmid = {33447803}, issn = {2590-2075}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, abstract = {It has long been recognized that biofilms are viscoelastic materials, however the importance of this attribute to the survival and persistence of these microbial communities is yet to be fully realized. Here we review work, which focuses on understanding biofilm mechanics and put this knowledge in the context of biofilm survival, particularly for biofilm-associated infections. We note that biofilm viscoelasticity may be an evolved property of these communities, and that the production of multiple extracellular polymeric slime components may be a way to ensure the development of biofilms with complex viscoelastic properties. We discuss viscoelasticity facilitating biofilm survival in the context of promoting the formation of larger and stronger biofilms when exposed to shear forces, promoting fluid-like behavior of the biofilm and subsequent biofilm expansion by viscous flow, and enabling resistance to both mechanical and chemical methods of clearance. We conclude that biofilm viscoelasticity contributes to the virulence of chronic biofilm infections.}, } @article {pmid33447801, year = {2020}, author = {Subramanian, S and Huiszoon, RC and Chu, S and Bentley, WE and Ghodssi, R}, title = {Microsystems for biofilm characterization and sensing - A review.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100015}, pmid = {33447801}, issn = {2590-2075}, abstract = {Biofilms are the primary cause of clinical bacterial infections and are impervious to typical amounts of antibiotics, necessitating very high doses for elimination. Therefore, it is imperative to have suitable methods for characterization to develop novel methods of treatment that can complement or replace existing approaches using significantly lower doses of antibiotics. This review presents some of the current developments in microsystems for characterization and sensing of bacterial biofilms. Initially, we review current standards for studying biofilms that are based on invasive and destructive end-point biofilm characterization. Additionally, biofilm formation and growth is extremely sensitive to various growth and environmental parameters that cause large variability in biofilms between repeated experiments, making it very difficult to compare experimental repeats and characterize the temporal characteristics of these organisms. To address these challenges, recent developments in the field have moved toward systems and miniature devices that can aid in the non-invasive characterization of bacterial biofilms. Our review focuses on several types of microsystems for biofilm evaluation including optical, electrochemical, and mechanical systems. This review will show how these devices can lead to better understanding of the physiology and function of these communities of bacteria, which can eventually lead to the development of novel treatments that do not rely on high-dosage antibiotics.}, } @article {pmid33447800, year = {2020}, author = {Matysik, A and Ho, FK and Ler Tan, AQ and Vajjala, A and Kline, KA}, title = {Cellular chaining influences biofilm formation and structure in group A Streptococcus.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100013}, pmid = {33447800}, issn = {2590-2075}, abstract = {Group A Streptococcal (GAS) biofilm formation is an important pathological feature contributing to the antibiotic tolerance and progression of various GAS infections. Although a number of bacterial factors have been described to promote in vitro GAS biofilm formation, the relevance of in vitro biofilms to host-associated biofilms requires further understanding. In this study, we demonstrate how constituents of the host environment, such as lysozyme and NaCl, can modulate GAS bacterial chain length and, in turn, shape GAS biofilm morphology and structure. Disruption of GAS chains with lysozyme results in biofilms that are more stable. Based on confocal microscopy, we attribute the increase in biofilm stability to a dense and compact three-dimensional structure produced by de-chained cells. To show that changes in biofilm stability and structure are due to the shortening of bacterial chains and not specific to the activity of lysozyme, we demonstrate that augmented chaining induced by NaCl or deletion of the autolysin gene mur1.2 produced defects in biofilm formation characterized by a loose biofilm architecture. We conclude that GAS biofilm formation can be directly influenced by host and environmental factors through the modulation of bacterial chain length, potentially contributing to persistence and colonization within the host. Further studies of in vitro biofilm models incorporating physiological constituents such as lysozyme may uncover new insights into the physiology of in vivo GAS biofilms.}, } @article {pmid33447797, year = {2020}, author = {Allkja, J and Bjarnsholt, T and Coenye, T and Cos, P and Fallarero, A and Harrison, JJ and Lopes, SP and Oliver, A and Pereira, MO and Ramage, G and Shirtliff, ME and Stoodley, P and Webb, JS and Zaat, SAJ and Goeres, DM and Azevedo, NF}, title = {Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100010}, pmid = {33447797}, issn = {2590-2075}, abstract = {The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.}, } @article {pmid33447795, year = {2019}, author = {Jensen, PØ and Møller, SA and Lerche, CJ and Moser, C and Bjarnsholt, T and Ciofu, O and Faurholt-Jepsen, D and Høiby, N and Kolpen, M}, title = {Improving antibiotic treatment of bacterial biofilm by hyperbaric oxygen therapy: Not just hot air.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100008}, pmid = {33447795}, issn = {2590-2075}, abstract = {Bacteria and fungi show substantial increased recalcitrance when growing as infectious biofilms. Chronic infections caused by biofilm growing microorganisms is considered a major problem of modern medicine. New strategies are needed to improve antibiotic treatment of biofilms. We have improved antibiotic treatment of bacterial biofilms by reviving the dormant bacteria and thereby make them susceptible to antibiotics by means of reoxygenation. Here we review the rationale for associating lack of oxygen with low susceptibility in infectious biofilm, and how hyperbaric oxygen therapy may result in reoxygenation leading to enhanced bactericidal activity of antibiotics. We address issues of feasibility and potential adverse effects regarding patient safety and development of resistance. Finally, we propose means for supplying reoxygenation to antibiotic treatment of infectious biofilm with the potential to benefit large groups of patients.}, } @article {pmid33447794, year = {2019}, author = {Kjeldgaard, B and Listian, SA and Ramaswamhi, V and Richter, A and Kiesewalter, HT and Kovács, ÁT}, title = {Fungal hyphae colonization by Bacillus subtilis relies on biofilm matrix components.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100007}, pmid = {33447794}, issn = {2590-2075}, abstract = {Bacteria interact with their environment including microbes and higher eukaryotes. The ability of bacteria and fungi to affect each other are defined by various chemical, physical and biological factors. During physical association, bacterial cells can directly attach and settle on the hyphae of various fungal species. Such colonization of mycelia was proposed to be dependent on biofilm formation by the bacteria, but the essentiality of the biofilm matrix was not represented before. Here, we demonstrate that secreted biofilm matrix components of the soil-dwelling bacterium, Bacillus subtilis are essential for the establishment of a dense bacterial population on the hyphae of the filamentous black mold fungus, Aspergillus niger and the basidiomycete mushroom, Agaricus bisporus. We further illustrate that these matrix components can be shared among various mutants highlighting the community shaping impact of biofilm formers on bacteria-fungi interactions.}, } @article {pmid33447793, year = {2019}, author = {Kragh, KN and Alhede, M and Kvich, L and Bjarnsholt, T}, title = {Into the well-A close look at the complex structures of a microtiter biofilm and the crystal violet assay.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100006}, pmid = {33447793}, issn = {2590-2075}, abstract = {The microtiter assay is one of the most widely used methods for assessing biofilm formation. Though it has high throughput, this assay is known for its substantial deviation from experiment to experiment, and even from well to well. Since the assay constitutes one of the pillars of biofilm research, it was decided to examine the wells of a microtiter plate directly during growth, treatment, and the steps involved in crystal violet (CV) measurements. An inverted Zeiss LSM 880 confocal laser scanning microscope was used to visualize and quantify biomass directly in the wells of the microtiter plate. Green fluorescent protein-tagged Pseudomonas aeruginosa, PAO1, and live/dead stains were used to assess the structure, state, and position of biomass build-up. Microscopic observations were compared with colony-forming unit (CFU) and CV measurements. The development and the structured architecture of biomass was observed in real-time in the wells. Three-dimensional images of biomass were obtained from all of the microtiter wells; these showed variations from well to well. CV staining showed large variations in remaining biomass, depending on the method selected to remove the supernatant prior to CV staining (i.e. pipetting or manually discarding the fluid by inversion, washed or unwashed wells). Colony-forming unit counts or live/dead staining used to evaluate biomass with or without antibiotic treatment proved imprecise due to aggregation, limited removal of biomass, and overestimation of dead staining. The highly structured microenvironment of biomass in microtiter wells needs to be considered when designing and analyzing experiments. When using microtiter plates, stochastic variation due to growth and handling may lead to flawed conclusions. It is therefore recommended that this assay be used as a screening tool rather than as a stand-alone experimental tool.}, } @article {pmid33447792, year = {2019}, author = {Ha, PT and He, R and Killiny, N and Brown, JK and Omsland, A and Gang, DR and Beyenal, H}, title = {Host-free biofilm culture of "Candidatus Liberibacter asiaticus," the bacterium associated with Huanglongbing.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100005}, pmid = {33447792}, issn = {2590-2075}, abstract = {Inability to culture the phloem-restricted alpha-proteobacterium "Candidatus Liberibacter asiaticus" ("Ca. L. asiaticus") or the closely related species ("Candidatus Liberibacter americanus" and "Candidatus Liberibacter africanus") that are associated with Huanglongbing (HLB) hampers the development of effective long-term control strategies for this devastating disease. Here we report successful establishment and long-term maintenance of host-free "Ca. L. asiaticus" cultures, with the bacterium growing within cultured biofilms derived from infected citrus tissue. The biofilms were grown in a newly designed growth medium under specific conditions. The initial biofilm-based culture has been successfully maintained for over two years and has undergone over a dozen subcultures. Multiple independent cultures have been established and maintained in a biofilm reactor system, opening the door to the development of pure culture of "Ca. L. asiaticus" and the use of genetics-based methods to understand and mitigate the spread of HLB.}, } @article {pmid33448817, year = {2019}, author = {Wang, H and Song, Z and Gu, J and Li, S and Wu, Y and Han, H}, title = {Nitrogen-Doped Carbon Quantum Dots for Preventing Biofilm Formation and Eradicating Drug-Resistant Bacteria Infection.}, journal = {ACS biomaterials science & engineering}, volume = {5}, number = {9}, pages = {4739-4749}, doi = {10.1021/acsbiomaterials.9b00583}, pmid = {33448817}, issn = {2373-9878}, abstract = {The development of novel antimicrobial agents is a top priority in the fight against drug-resistant bacteria. Here, we synthesized a green nanoantibiotic, nitrogen-doped carbon quantum dots (N-CQDs) from bis-quaternary ammonium salt (BQAS) as carbon and nitrogen sources. The as-obtained N-CQDs possess high antibacterial activity (>99%) against both methicillin-resistant Staphylococcus aureus (MRSA) and Ampicillin-resistant Escherichia coli bacteria in vitro than some known clinical antibiotics (vancomycin and gentamicin). The N-CQDs can kill MRSA pathogens without inducing resistance, prevent biofilm formation and eliminate established biofilm and persister cells. The treatment of N-CQDs can significantly reduce the amount of bacteria on the infected tissue and accelerate wound healing. The N-CQDs are positively charged, thus enabling them to interact with bacterial cell membrane through electrostatic interaction, leading to severe damage and an increased permeability of the cell membrane, which further promotes the penetration of N-CQDs into the membrane and induces the degradation of DNA by N-CQDs generated reactive oxygen species. The N-CQDs also play a role in obstructing the intracellular metabolic pathways of MRSA. The overall data demonstrate the green nanoantibiotic as an excellent eradicator of biofilm and persister cells as well as a promising antibacterial candidate for treating infections induced by drug-resistant bacteria.}, } @article {pmid33447790, year = {2019}, author = {Coenye, T and Kjellerup, BV and Kovács, ÁT and Goeres, D}, title = {Biofilm: Introducing a new journal for the broad biofilm field.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100003}, doi = {10.1016/j.bioflm.2019.100003}, pmid = {33447790}, issn = {2590-2075}, } @article {pmid33447789, year = {2019}, author = {Van Acker, H and Crabbé, A and Jurėnas, D and Ostyn, L and Sass, A and Daled, S and Dhaenens, M and Deforce, D and Teirlinck, E and De Keersmaecker, H and Braeckmans, K and Van Melderen, L and Coenye, T}, title = {The role of small proteins in Burkholderia cenocepacia J2315 biofilm formation, persistence and intracellular growth.}, journal = {Biofilm}, volume = {1}, number = {}, pages = {100001}, pmid = {33447789}, issn = {2590-2075}, abstract = {Burkholderia cenocepacia infections are difficult to treat due to resistance, biofilm formation and persistence. B. cenocepacia strain J2315 has a large multi-replicon genome (8.06 Mb) and the function of a large fraction of (conserved) hypothetical genes remains elusive. The goal of the present study is to elucidate the role of small proteins in B. cenocepacia, focusing on genes smaller than 300 base pairs of which the function is unknown. Almost 10% (572) of the B. cenocepacia J2315 genes are smaller than 300 base pairs and more than half of these are annotated as coding for hypothetical proteins. For 234 of them no similarity could be found with non-hypothetical genes in other bacteria using BLAST. Using available RNA sequencing data obtained from biofilms, a list of 27 highly expressed B. cenocepacia J2315 genes coding for small proteins was compiled. For nine of them expression in biofilms was also confirmed using LC-MS based proteomics and/or expression was confirmed using eGFP translational fusions. Overexpression of two of these genes negatively impacted growth, whereas for four others overexpression led to an increase in biofilm biomass. Overexpression did not have an influence on the MIC for tobramycin, ciprofloxacin or meropenem but for five small protein encoding genes, overexpression had an effect on the number of persister cells in biofilms. While there were no significant differences in adherence to and invasion of A549 epithelial cells between the overexpression mutants and the WT, significant differences were observed in intracellular growth/survival. Finally, the small protein BCAM0271 was identified as an antitoxin belonging to a toxin-antitoxin module. The toxin was found to encode a tRNA acetylase that inhibits translation. In conclusion, our results confirm that small proteins are present in the genome of B. cenocepacia J2315 and indicate that they are involved in various biological processes, including biofilm formation, persistence and intracellular growth.}, } @article {pmid33654766, year = {2019}, author = {Shao, X and Xie, Y and Zhang, Y and Deng, X}, title = {Biofilm Formation Assay in Pseudomonas syringae.}, journal = {Bio-protocol}, volume = {9}, number = {10}, pages = {e3237}, pmid = {33654766}, issn = {2331-8325}, abstract = {Pseudomonas syringae is a model plant pathogen that infects more than 50 plant species worldwide, thus leading to significant yield loss. Pseudomonas biofilm always adheres to the surfaces of medical devices or host cells, thereby contributing to infection. Biofilm formation can be visualized on numerous matrixes, including coverslips, silicone tubes, polypropylene and polystyrene. Confocal laser scanning microscopy can be used to visualize and analyze biofilm structure. In this study, we modified and applied the current method of P. aeruginosa biofilm measurement to P. syringae, and developed a convenient protocol to visualize P. syringae biofilm formation using a borosilicate glass tube as the matrix coupled with crystal violet staining.}, } @article {pmid33817061, year = {2018}, author = {Peng, L and Xiong, Y and Wang, M and Han, M and Cai, W and Li, Z}, title = {Chemical Composition of Essential Oil in Mosla Chinensis Maxim Cv. Jiangxiangru and its Inhibitory Effect on Staphylococcus Aureus Biofilm Formation.}, journal = {Open life sciences}, volume = {13}, number = {}, pages = {1-10}, pmid = {33817061}, issn = {2391-5412}, abstract = {The essential oil of Mosla chinensis Maxim cv. Jiangxiangru is known for its antibacterial ability. This study aimed to investigate the chemical composition of Jiangxiangru essential oil and its inhibitory effect on Staphylococcus aureus biofilm formation. Gas chromatography/mass spectrometry (GC-MS) was used to determine the chemical composition of Jiangxiangru essential oil. Subsequently, the eight major chemical components were quantitatively analyzed using GC- MS, and their minimum inhibitory concentration (MIC) values against S. aureus were tested. Biofilm formation was detected by crystal violet semi-quantitative method and silver staining. Of the 59 peaks detected, 29 were identified by GC-MS. Of these peaks, thymol, carvacrol, p-cymene, γ-terpinene, thymol acetate, α-caryophyllene, 3-carene, and carvacryl acetate were present at a relatively higher concentration. The results of the quantitative test showed that thymol, carvacrol, p-cymene, and γ-terpinene were the major components of the essential oil. Among the eight reference substances, only thymol, carvacrol, and thymol acetate had lower MICs compared with the essential oil. Essential oil, carvacrol, carvacryl acetate, α-caryophyllene, and 3-carene showed the better inhibition of S. aureus biofilm formation. When one fourth of the MIC concentrations were used for these substances (0.0625 mg/mL for essential oil, 0.0305 mg/mL for carvacrol, 1.458 mg/mL for carvacryl acetate, 0.1268 mg/mL for α-caryophyllene, and 2.5975 mg/mL for 3-carene), the inhibition rates were over 80%. However, thymol, γ-terpinene, thymol acetate, and p-cymene showed a relatively poor inhibition of S. aureus biofilm formation. When 1× MIC concentrations of these substances were used, the inhibition rates were less than 50%. In conclusion, Jiangxiangru essential oil and its major components, carvacrol, carvacryl acetate, α-caryophyllene, and 3-carene, strongly inhibited biofilm formation in S. aureus.}, } @article {pmid33465928, year = {2017}, author = {Dasgupta, Q and Madras, G and Chatterjee, K}, title = {Controlled Release of Usnic Acid from Biodegradable Polyesters to Inhibit Biofilm Formation.}, journal = {ACS biomaterials science & engineering}, volume = {3}, number = {3}, pages = {291-303}, doi = {10.1021/acsbiomaterials.6b00680}, pmid = {33465928}, issn = {2373-9878}, abstract = {Controlled and sustained release of antibacterial drugs is a promising approach to address challenges related to bacterial infections in biomedical implants. Biocompatible polyols like xylitol and mannitol are frequently used to synthesize cross-linked, biodegradable polyesters. Xylitol-based adipoyl and sebacoyl polyesters were synthesized by a catalyst free melt polyesterification technique. Unlike traditional drug delivery systems, the objective of this work was to develop biodegradable polymers with usnic acid (UA), a known antibacterial agent, entrapped in the polymer network. Apart from offering a wider control of the release kinetics and improved processability, the hydrolytic degradation results in the concomitant resorption of the polymer. Polymer properties such as degradation, modulus, and drug release were tuned through a subtle change in the chain length of the diacid. In 1 week, the xylitol based adipoyl ester degrades 41% and releases 25% of its initial drug loading whereas the sebacoyl ester degrades 23% in and releases 9% of the loaded drug. A kinetic model has been used to understand the UA release profiles and determine degradation and release parameters that influence release from the polymers. These polyesters are cytocompatible and exhibit excellent bactericidal activity against Staphyloccus aureus by inducing oxidative stress. This work enables a strategy to synthesize biodegradable polymers for potential to inhibit biofilm formation in vivo with tunable mechanical and degradation properties, and variable controlled release.}, } @article {pmid33579076, year = {2016}, author = {Anutrakunchai, C and Hemsley, H and Sermswan, RW and Titball, RW and Chareonsudjai, S and Taweechaisupapong, S}, title = {Role of RelA and SpoT in Burkholderia pseudomallei survival, biofilm formation and ceftazidime tolerance during nutritional stress.}, journal = {Tropical biomedicine}, volume = {33}, number = {4}, pages = {786-798}, pmid = {33579076}, issn = {2521-9855}, abstract = {Burkholderia pseudomallei a saprophyte found in soil and stagnant water is the causative agent of human melioidosis, an often cause fatal disease. B. pseudomallei is intrinsically resistant to many antibiotics. The stringent response is a global bacterial adaptation process in response to nutritional limitation and is mediated by the alarmone (p)ppGpp, which is produced by two proteins, RelA and SpoT. In order to test whether the stringent response is involved in ceftazidime tolerance, biofilm formation, and bacterial survival in the soil microcosm, B. pseudomallei strain K96243 and its isogenic ΔrelA and ΔrelAΔspoT mutants were grown in rich and nutrient-limited media. In nutrient-limiting conditions, both the wild type and mutants were found to be up to 64-times more tolerant to ceftazidime than when grown in rich culture conditions. Moreover, the biofilm formation of all bacterial isolates tested were significantly higher under nutrient-limiting conditions than under nutrient-rich conditions. The ΔrelAΔspoT mutant produced less biofilm than its wild type or ΔrelA mutant under nutrient-limiting conditions. The survival of the ΔrelAΔspoT double mutant cultured in 1% moisture content soil was significantly decreased compared to the wild type and the ΔrelA mutant. Therefore, the RelA/SpoT protein family might represent a promising target for the development of novel antimicrobial agents to combat B. pseudomallei.}, } @article {pmid34046294, year = {2016}, author = {Fuchs, A and Tripet, BP and Ammons, MCB and Copié, V}, title = {Optimization of Metabolite Extraction Protocols for the Identification and Profiling of Small Molecule Metabolites from Planktonic and Biofilm Pseudomonas aeruginosa Cultures.}, journal = {Current Metabolomics}, volume = {4}, number = {2}, pages = {141-147}, pmid = {34046294}, issn = {2213-235X}, support = {K01 GM103821/GM/NIGMS NIH HHS/United States ; S10 RR026659/RR/NCRR NIH HHS/United States ; }, abstract = {BACKGROUND: Metabolomics aims to characterize the metabolic phenotype and metabolic pathways utilized by microorganisms or other cellular systems. A crucial component to metabolomics research as it applies to microbial metabolism is the development of robust and reproducible methods for extraction of intracellular metabolites. The goal is to extract all metabolites in a non-biased and consistent manner; however, most methods used thus far are targeted to specific metabolite classes and use harsh conditions that may contribute to metabolite degradation. Metabolite extraction methodologies need to be optimized for each microorganism of interest due to different cellular characteristics contributing to lysis resistance.

METHODS: Three cell pellet wash solutions were compared for the potential to influence intracellular metabolite leakage of P. aeruginosa. We also compared four different extraction methods using (i) methanol:chloroform (2:1); (ii) 50% methanol; (iii) 100% methanol; or (iv) 100% water to extract intracellular metabolites from P. aeruginosa planktonic and biofilm cultures.

RESULTS: Intracellular metabolite extraction efficiency was found to be dependent on the extraction method and varies between microbial modes of growth. Methods using the 60% methanol wash produced the greatest amount of intracellular material leakage. Quantification of intracellular metabolites via [1]H NMR showed that extraction protocols using 100% water or 50% methanol achieved the greatest extraction efficiencies, while addition of sonication to facilitate cell lysis to the 50% methanol extraction method resulted in at least a two-fold increase in signal intensities for approximately half of the metabolites identified. Phosphate buffered saline (PBS) was determined to be the most appropriate wash solution, yielding little intracellular metabolite leakage from cells.

CONCLUSION: We determined that washing in 1X PBS and extracting intracellular metabolites with 50% methanol is the most appropriate metabolite extraction protocol because (a) leakage is minimal; (b) a broad range of metabolites present at sufficiently high concentrations is detectable by NMR; and (c) this method proved suitable for metabolite extraction of both planktonic and biofilm P. aeruginosa cultures.}, } @article {pmid33451238, year = {2003}, author = {Chmielewski, RAN and Frank, JF}, title = {Biofilm Formation and Control in Food Processing Facilities.}, journal = {Comprehensive reviews in food science and food safety}, volume = {2}, number = {1}, pages = {22-32}, doi = {10.1111/j.1541-4337.2003.tb00012.x}, pmid = {33451238}, issn = {1541-4337}, abstract = {Microorganisms on wet surfaces have the ability to aggregate, grow into microcolonies, and produce biofilm. Growth of biofilms in food processing environments leads to increased opportunity for microbial contamination of the processed product. These biofilms may contain spoilage and pathogenic microorganisms. Microorganisms within biofilms are protected from sanitizers increasing the likelihood of survival and subsequent contamination of food. This increases the risk of reduced shelf life and disease transmission. Extracellular polymeric substances associated with biofilm that are not removed by cleaning provide attachment sites for microorganisms newly arrived to the cleaned system. Biofilm formation can also cause the impairment of heat transfer and corrosion to metal surfaces. Some of the methods used to control biofilm formation include mechanical and manual cleaning, chemical cleaning and sanitation, and application of hot water.}, } @article {pmid33445481, year = {2021}, author = {Camargo, SEA and Roy, T and Xia, X and Fares, C and Hsu, SM and Ren, F and Clark, AE and Neal, D and Esquivel-Upshaw, JF}, title = {Novel Coatings to Minimize Corrosion of Titanium in Oral Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {14}, number = {2}, pages = {}, pmid = {33445481}, issn = {1996-1944}, support = {R01 DE025001/DE/NIDCR NIH HHS/United States ; }, abstract = {The aim of this work is to investigate the effects produced by polymicrobial biofilm (Porphyromonas gingivalis, Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius) on the corrosion behavior of titanium dental implants. Pure titanium disks were polished and coated with titanium nitride (TiN) and silicon carbide (SiC) along with their quarternized versions. Next, the disks were cultivated in culture medium (BHI) with P. gingivalis, S. mutans, S. sanguinis, and S. salivarius and incubated anaerobically at 37 °C for 30 days. Titanium corrosion was evaluated through surface observation using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Furthermore, the Ti release in the medium was evaluated by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). SEM images showed that coated Ti disks exhibited lower corrosion compared to non-coated disks, except for the quartenized TiN. This was confirmed by AFM, where the roughness was higher in non-coated Ti disks. ICP showed that Ti levels were low in all coating disks. These results indicate that these SiC and TiN-based coatings could be a useful tool to reduce surface corrosion on titanium implant surfaces.}, } @article {pmid33444856, year = {2021}, author = {El-Far, A and Samir, S and El-Gebaly, E and Taha, NY and Fahmy, EM and Diab, TM and El-Shenawy, A}, title = {Assessment of eugenol inhibitory effect on biofilm formation and biofilm gene expression in methicillin resistant Staphylococcus aureus clinical isolates in Egypt.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {89}, number = {}, pages = {104722}, doi = {10.1016/j.meegid.2021.104722}, pmid = {33444856}, issn = {1567-7257}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Egypt ; Eugenol/*pharmacology ; Gene Expression/*drug effects ; Genes, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics ; Microbial Sensitivity Tests ; Polymerase Chain Reaction/methods ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection is a major threat in Healthcare facilities. The search for biofilm inhibitors is essential to overcome the antibiotic resistance. Eugenol is a phyto-compound that possesses many biological properties. In this study, the aim was to estimate the effect of eugenol on biofilms of MRSA through quantifying the level of gene expression of three genes (IcaA, IcaD and SarA) involved in biofilm development.. Fifty MRSA biofilm producers collected from the microbiology lab at Theodor Bilharz Research Institute were incubated with different concentrations of eugenol for 24 h. The minimum inhibitory concentration of eugenol (MIC) that eradicates the biofilms growth was detected. mRNA was extracted from all isolates before and after the application of eugenol at 0.5 x MIC, and then subjected to quantitative real-time PCR (qPCR). Results showed that fourteen isolates out of 50 (28%) exhibited intermediate biofilm formation ability, and 36 out of 50 (72%) were strong biofilm producers. The MIC values of eugenol for MRSA ranged from 3.125% to 0.01%. The mean values of MIC in both strong and intermediate biofilm forming MRSA isolates were statistically comparable (p = 0.202). qPCR results revealed that the levels of expression of the studied genes IcaA, IcaD, and SarA were decreased after eugenol treatment when compared with their corresponding values before treatment (p = 0.001). Eugenol inhibited the formation of biofilm of MRSA isolates, indicating it could be used to control infections associated with MRSA biofilms.}, } @article {pmid33441765, year = {2021}, author = {Kannan, S and Solomon, A and Krishnamoorthy, G and Marudhamuthu, M}, title = {Liposome encapsulated surfactant abetted copper nanoparticles alleviates biofilm mediated virulence in pathogenic Pseudomonas aeruginosa and MRSA.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {1102}, pmid = {33441765}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/drug effects ; Humans ; Lipopeptides/administration & dosage/*pharmacology ; Liposomes ; Methicillin-Resistant Staphylococcus aureus/*drug effects/pathogenicity/physiology ; Paenibacillus/chemistry ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/pathogenicity/physiology ; Staphylococcal Infections/drug therapy/microbiology ; Surface-Active Agents/administration & dosage/*pharmacology ; Virulence/drug effects ; }, abstract = {In the present study lipopeptide biosurfactant with high emulsification capacity produced by human skin bacterium Paenibacillus thiaminolyticus was purified and subjected to FTIR and NMR spectral analysis which gave evidence of the active characteristics of the surfactant. To augment the antivirulent potential further, the mixer of copper and copper oxide nanoparticles (CuNPs) was synthesized, and characterized by UV-Visible spectroscopy, SEM-EDAX, TEM, and Zeta analysis. Here, we attempted to enhance the antimicrobial and antibiofilm activity with the assistance of encapsulated preparation of lipopeptide and CuNPs in multilamellar liposomes. The proposed mechanism of action of lipopeptide and CuNPs liposomal preparation negatively influences the cell metabolism, secreted virulence such as staphyloxanthin, pyocyanin, and extracellular polysaccharides. The significant decline in the growth of MRSA and P. aeruginosa in both planktonic form and biofilm by lipopeptide and CuNPs treatment were visualized using scanning electron microscopy and High content screening imaging system. In vivo studies revealed that treatment with lipopeptide and CuNPs in multilamellar liposomes extended the lifespan of infected Caenorhabditis elegans by about 75%. Therefore, this study typifies lipopeptide and CuNPs could credibly be a substantial substitute over conventional antibiotics in averting the biofilm associated pathogenesis of MRSA and P. aeruginosa.}, } @article {pmid33440352, year = {2021}, author = {Han, X and Zhang, G and Chai, M and Zhang, X}, title = {Light-assisted therapy for biofilm infected micro-arc oxidation TiO2 coating on bone implants.}, journal = {Biomedical materials (Bristol, England)}, volume = {16}, number = {2}, pages = {025018}, doi = {10.1088/1748-605X/abdb72}, pmid = {33440352}, issn = {1748-605X}, mesh = {3T3 Cells ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Bone Substitutes ; Bone and Bones/*physiology ; Cell Adhesion ; Cell Proliferation ; Coated Materials, Biocompatible/pharmacology ; Copper/chemistry ; Disulfides/chemistry ; In Vitro Techniques ; Ions ; Male ; Mice ; Microbial Sensitivity Tests ; Molybdenum/chemistry ; Osteoblasts/drug effects ; Osteogenesis/drug effects ; Photochemistry ; Rats ; Reactive Oxygen Species ; Silver/chemistry ; Staphylococcus aureus/metabolism ; Surface Properties ; Titanium/*chemistry ; Zinc/chemistry ; }, abstract = {Implant-associated infections is a main factor leading to the failure of titanium (Ti) implants. Micro-arc oxidation is a convenient and effective technique to form a biocompatible metal (Ag[+], Cu[2+] and Zn[2+]) ions-doped TiO2 coatings to combat bacterial infections. However, compared with the sterilization by metal ions, light-triggered antibacterial therapies have accepted more attention due to its higher antibacterial efficiency and security. Although TiO2 is an excellent photocatalyst, it can be triggered by ultraviolet light due to the wide band gap. Herein, molybdenum disulfide (MoS2) modified TiO2 coating was fabricated on Ti by a hybrid process of micro-arc oxidation and hydrothermal treatment. The hybrid coating exhibits excellent antibacterial activity under the irradiation of 808 nm near-infrared light because of the synergistic antibacterial effects of reactive oxygen species and hyperthermia, and Staphylococcus aureus (S. aureus) biofilm can be eradicated within 15 min both in vivo and in vitro. Furthermore, collagen decorated on the surface of the hybrid coating can improve the proliferation, adhesion and spreading of MC3T3-E1 osteoblasts.}, } @article {pmid33440288, year = {2021}, author = {Bellich, B and Jou, IA and Buriola, C and Ravenscroft, N and Brady, JW and Fazli, M and Tolker-Nielsen, T and Rizzo, R and Cescutti, P}, title = {The biofilm of Burkholderia cenocepacia H111 contains an exopolysaccharide composed of l-rhamnose and l-mannose: Structural characterization and molecular modelling.}, journal = {Carbohydrate research}, volume = {499}, number = {}, pages = {108231}, pmid = {33440288}, issn = {1873-426X}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; Burkholderia cenocepacia/chemistry/*metabolism ; Carbohydrate Conformation ; Mannose/chemistry/*metabolism ; Models, Molecular ; Polysaccharides, Bacterial/chemistry/*metabolism ; Rhamnose/chemistry/*metabolism ; }, abstract = {Burkholderia cenocepacia belongs to the Burkholderia Cepacia Complex, a group of 22 closely related species both of clinical and environmental origin, infecting cystic fibrosis patients. B. cenocepacia accounts for the majority of the clinical isolates, comprising the most virulent and transmissible strains. The capacity to form biofilms is among the many virulence determinants of B. cenocepacia, a characteristic that confers enhanced tolerance to some antibiotics, desiccation, oxidizing agents, and host defenses. Exopolysaccharides are a major component of biofilm matrices, particularly providing mechanical stability to biofilms. Recently, a water-insoluble exopolysaccharide produced by B. cenocepacia H111 in biofilm was characterized. In the present study, a water-soluble exopolysaccharide was extracted from B. cenocepacia H111 biofilm, and its structure was determined by GLC-MS, NMR and ESI-MS. The repeating unit is a linear rhamno-tetrasaccharide with 50% replacement of a 3-α-L-Rha with a α-3-L-Man. [2)-α-L-Rhap-(1→3)-α-L-[Rhap or Manp]-(1→3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→]n Molecular modelling was used to obtain information about local structural motifs which could give information about the polysaccharide conformation.}, } @article {pmid33440209, year = {2021}, author = {Gupta, P and Goel, A and Singh, KR and Meher, MK and Gulati, K and Poluri, KM}, title = {Dissecting the anti-biofilm potency of kappa-carrageenan capped silver nanoparticles against Candida species.}, journal = {International journal of biological macromolecules}, volume = {172}, number = {}, pages = {30-40}, doi = {10.1016/j.ijbiomac.2021.01.035}, pmid = {33440209}, issn = {1879-0003}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Carrageenan/*pharmacology ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests/methods ; Silver/*chemistry ; }, abstract = {Global antimicrobial crisis and advent of drug resistant fungal strains has substantially distressed disease management for clinicians. Biodegradable silver nanoparticles (AgNps) emerge as an excellent alternative remedial option. In the current study, the anti-biofilm activity of microwave irradiated kappa-carrageenan (CRG) capped AgNps against Candida albicans, and Candida glabrata was investigated in terms of their effect on reactive oxygen species (ROS) generation, cellular morphology, biochemical composition, and the activity of enzymes of extracellular matrix. Minimum inhibitory concentration and fungicidal concentration value of CRG-AgNps against both Candida spp. ranged between 400 and 500 μg/mL. The 80% of Candida biofilm was inhibited and eradicated by CRG-AgNps at a concentration of ~300 μg/mL. Microscopic studies indicate that CRG-AgNps caused morphological damage through membrane disruption and pore formation. Further, CRG-AgNps generated ROS in a concentration-dependent manner and modulated the composition of Candida biofilm ECM by increasing the carbohydrate and eDNA content. CRG-AgNps also significantly inactivated the hydrolytic enzymes, thus hindering the biofilm forming ability. In conclusion, all these results suggest that the CRG-AgNps are potential antifungal agents against Candida biofilms, and they inhibit/eradicate the fungal biofilms through multiple signalling mechanisms.}, } @article {pmid33439086, year = {2021}, author = {Serena, TE and Jalodi, O and Serena, L and Patel, K and Mynti, M}, title = {Evaluation of the combination of a biofilm-disrupting agent and negative pressure wound therapy: a case series.}, journal = {Journal of wound care}, volume = {30}, number = {1}, pages = {9-14}, doi = {10.12968/jowc.2021.30.1.9}, pmid = {33439086}, issn = {0969-0700}, mesh = {Adult ; Aged ; Bandages ; *Biofilms ; Humans ; *Negative-Pressure Wound Therapy ; Pressure Ulcer/*therapy ; Prospective Studies ; *Wound Healing/physiology ; }, abstract = {OBJECTIVE: Approximately three million people in the US have hard-to-heal pressure ulcers (PUs), including 10% of hospitalised patients. Healing depends on ulcer stage and patient comorbidities. Despite advances in nutrition and wound care, PUs can take months or years to reach complete closure. To date, clinical studies have focused on single modality therapy. However, there is no one therapy that can address all of the deficits in these complex, hard-to-heal wounds. A commonly used treatment for PUs, negative pressure wound therapy (NPWT), has demonstrated improved healing in Stage 3 and 4 PUs. NPWT entails applying suction to a porous sponge fitted into the wound cavity and sealed with an occlusive dressing. Negative pressure facilitates wound healing by removing wound fluid containing harmful proteases, stimulating the formation of granulation tissue and promoting wound contracture. However, it does not affect biofilm formation. We hypothesised that adding an antibiofilm agent might increase the effectiveness of NPWT in recalcitrant PUs.

METHOD: A prospective case series was conducted in outpatient wound care centres and a skilled nursing facility to examine the combination of a biofilm-disrupting antimicrobial agent (Blast-X, Next Science, US) in combination with NPWT (VAC, 3M, US) in healing and reducing bacterial burden in treatment-resistant pressure ulcers. Patients consented to application of the antibiofilm agent and NPWT three times per week for four weeks. The wounds were measured, imaged for bacteria and tested for host and bacterial protease activity weekly.

RESULTS: Of the 10 patients, four dropped out of the study before the end of the four weeks. Of the remaining six, four patients experienced a reduction in wound surface area and volume, reduced protease activity and lower bacterial levels.

CONCLUSION: The results of this study showed that multimodal therapy, including NPWT and biofilm disruption, may restart the healing of stagnant treatment-resistant PUs.}, } @article {pmid33437398, year = {2020}, author = {Wei, Q and Zhang, Z and Luo, J and Kong, J and Ding, Y and Chen, Y and Wang, K}, title = {Erratum: Insulin treatment enhances pseudomonas aeruginosa biofilm formation by increasing intracellular cyclic di-GMP levels, leading to chronic wound infection and delayed wound healing.}, journal = {American journal of translational research}, volume = {12}, number = {12}, pages = {8259-8261}, pmid = {33437398}, issn = {1943-8141}, abstract = {[This corrects the article on p. 3261 in vol. 11, PMID: 31312343.].}, } @article {pmid33435575, year = {2021}, author = {Landlinger, C and Tisakova, L and Oberbauer, V and Schwebs, T and Muhammad, A and Latka, A and Van Simaey, L and Vaneechoutte, M and Guschin, A and Resch, G and Swidsinski, S and Swidsinski, A and Corsini, L}, title = {Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo.}, journal = {Pathogens (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33435575}, issn = {2076-0817}, support = {876839//Österreichische Forschungsförderungsgesellschaft/ ; }, abstract = {Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13-8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.}, } @article {pmid33435345, year = {2021}, author = {Mushtaq, S and Ahmad, NM and Mahmood, A and Iqbal, M}, title = {Antibacterial Amphiphilic Copolymers of Dimethylamino Ethyl Methacrylate and Methyl Methacrylate to Control Biofilm Adhesion for Antifouling Applications.}, journal = {Polymers}, volume = {13}, number = {2}, pages = {}, pmid = {33435345}, issn = {2073-4360}, abstract = {Amphiphilic copolymers are recognized as important biomaterials and used as antibacterial agents due to their effective inhibition of bacterial growth. In current study, the amphiphilic copolymers of P(DMAEMA-co-MMA) were synthesized using free radical polymerization by varying the concentrations of hydrophilic monomer 2-dimethylamino ethylmethacrylate (DMAEMA) and hydrophobic monomer methyl methacrylate (MMA) having PDI value of 1.65-1.93. The DMAEMA monomer, through ternary amine with antibacterial property optimized copolymers, P(DMAEMA-co-MMA), compositions to control biofilm adhesion. Antibacterial activity of synthesized copolymers was elucidated against Gram-positive Staphylococcus aureus (ATCC 6538) and Gram-negative Escherchia coli (ATCC 8739) by disk diffusion method, and zones of inhibition were measured. The desired composition that was PDM1 copolymer had shown good zones of inhibition i.e., 19 ± 0.33 mm and 20 ± 0.33 mm for E. coli and S. aureus respectively. The PDM1 and PDM2 have exhibited significant control over bacterial biofilm adhesion as tested by six well plate method. SEM study of bacterial biofilm formation has illustrated that these copolymers act in a similar fashion like cationic biocide. These compositions viz. PDM1 and PDM2, may be useful in development of bioreactors, sensors, surgical equipment and drug delivery devices.}, } @article {pmid33435177, year = {2021}, author = {Slettengren, M and Linnros, M and van der Linden, J}, title = {Silicone Oil Decreases Biofilm Formation in a Capacitance-Based Automatic Urine Measurement System.}, journal = {Sensors (Basel, Switzerland)}, volume = {21}, number = {2}, pages = {}, pmid = {33435177}, issn = {1424-8220}, mesh = {Biofilms ; *Hemoglobins ; *Silicone Oils ; }, abstract = {Capacitance-based automatic urine measurement is a validated technique already implemented in clinical practice. However, albuminuria and free hemoglobinuria cause progressive biofilm buildup on the capacitance sensors of the urinometers. The aim of this experimental study is to investigate the influence of albumin and free hemoglobin on the capacitance signal of an automatic urinometer with and without the addition of silicone oil. A solution of Ringer's acetate mixed with either albumin or free hemoglobin was run through an automatic urinometer containing either a water-soluble capsule with silicone oil or not. In total, around 500 capacitance measurements were retrieved from the albumin and free hemoglobin group, respectively. The mean increase in capacitance in the albumin 3 g/L group was 257 ± 100 pF without and 105 ± 30 pF with silicone oil, respectively, during 24 h. After ten hours of recording, differences between the two albumin groups reached statistical significance. For the free hemoglobin groups (0.01 g/L), the mean increase in capacitance was 190 ± 170 pF with silicone oil, and 324 ± 80 pF without, with a significant difference between the groups after 20 h and onwards. Coating of the capacitance measurement membrane of the automatic urinometer by albumin or free hemoglobin was significantly decreased by silicone oil, prolonging the functionality of the device.}, } @article {pmid33434806, year = {2021}, author = {Du, Y and Yu, D and Wang, X and Zhen, J and Bi, C and Gong, X and Zhao, J}, title = {Achieving simultaneous nitritation, anammox and denitrification (SNAD) in an integrated fixed-biofilm activated sludge (IFAS) reactor: Quickly culturing self-generated anammox bacteria.}, journal = {The Science of the total environment}, volume = {768}, number = {}, pages = {144446}, doi = {10.1016/j.scitotenv.2020.144446}, pmid = {33434806}, issn = {1879-1026}, mesh = {*Ammonium Compounds ; Bacteria ; Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; Oxidation-Reduction ; *Sewage ; Wastewater ; }, abstract = {In this study, by inoculating nitritation suspended sludge, simultaneous nitritation, anammox and denitrification (SNAD) was established quickly in an integrated fixed-biofilm activated sludge (IFAS) reactor to treat high-ammonia municipal wastewater. Results showed that, deep-level total nitrogen and chemical oxygen demand removal efficiencies (92.8% and 78.8%, respectively) were achieved, and their effluent concentrations were 13.2 and 39.3 mg/L, respectively. Excess generation of nitrate was once occurred under continuous aerobic condition, but it could be solved by suppressing nitrite oxidizing bacteria activity stably via switching to intermittent aeration mode (alternate 7 min of aerobic and 21 min of anoxic) and rising influent ammonium concentration temporarily (lasted 31 days). High-throughput sequencing analysis revealed that, Candidatus_Brocadia, as dominant anammox bacteria, was self-generated in flocs (2.93%) but mainly biofilm (7.67%), whereas uncultured_f_Nitrosomonadaceae as ammonia oxidizing bacteria was mainly found in flocs (2.4%). This work not only demonstrated that anammox bacteria could be self-generated and retained in the SNAD-IFAS system, but also suggested a promising application of the SNAD-IFAS in wastewater treatment plants.}, } @article {pmid33434357, year = {2021}, author = {Alomary, MN and Ansari, MA}, title = {Proanthocyanin-Capped Biogenic TiO2 Nanoparticles with Enhanced Penetration, Antibacterial and ROS Mediated Inhibition of Bacteria Proliferation and Biofilm Formation: A Comparative Approach.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {27}, number = {18}, pages = {5817-5829}, doi = {10.1002/chem.202004828}, pmid = {33434357}, issn = {1521-3765}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Cell Proliferation ; *Metal Nanoparticles ; *Nanoparticles ; Reactive Oxygen Species ; Titanium ; }, abstract = {Biofunctionalized TiO2 nanoparticles with a size range of 18.42±1.3 nm were synthesized in a single-step approach employing Grape seed extract (GSE) proanthocyanin (PAC) polyphenols. The effect of PACs rich GSE corona was examined with respect to 1) the stability and dispersity of as-synthesized GSE-TiO2 -NPs, 2) their antiproliferative and antibiofilm efficacy, and 3) their propensity for internalization and reactive oxygen species (ROS) generation in urinary tract infections (UTIs) causing Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus saprophyticus strains. State-of-the-art techniques were used to validate GSE-TiO2 -NPs formation. Comparative Fourier transformed infrared (FTIR) spectral analysis demonstrated that PACs linked functional -OH groups likely play a central role in Ti[4+] reduction and nucleation to GSE-TiO2 -NPs, while forming a thin, soft corona around nascent NPs to attribute significantly enhanced stability and dispersity. Transmission electron microscopic (TEM) and inductively coupled plasma mass-spectroscopy (ICP-MS) analyses confirmed there was significantly (p<0.05) enhanced intracellular uptake of GSE-TiO2 -NPs in both Gram-negative and -positive test uropathogens as compared to bare TiO2 -NPs. Correspondingly, compared to bare NPs, GSE-TiO2 -NPs induced intracellular ROS formation that corresponded well with dose-dependent inhibitory patterns of cell proliferation and biofilm formation in both the tested strains. Overall, this study demonstrates that -OH rich PACs of GSE corona on biogenic TiO2 -NPs maximized the functional stability, dispersity and propensity of penetration into planktonic cells and biofilm matrices. Such unique merits warrant the use of GSE-TiO2 -NPs as a novel, functionally stable and efficient antibacterial nano-formulation to combat the menace of UTIs in clinical settings.}, } @article {pmid33433854, year = {2021}, author = {Salisbury, AM and Mullin, M and Foulkes, L and Chen, R and Percival, SL}, title = {The Ability of a Concentrated Surfactant Gel to Reduce an Aerobic, Anaerobic and Multispecies Bacterial Biofilm In Vitro.}, journal = {Advances in experimental medicine and biology}, volume = {1323}, number = {}, pages = {149-157}, pmid = {33433854}, issn = {0065-2598}, mesh = {Anaerobiosis ; Biofilms ; Humans ; Pseudomonas aeruginosa ; Staphylococcus aureus ; *Surface-Active Agents/pharmacology ; *Wound Infection/drug therapy ; }, abstract = {Biofilm formation in wounds can lead to increased inflammation, infection and delayed wound healing. Additionally, biofilms show increased recalcitrance to antimicrobials compared to their planktonic counterparts making them difficult to manage and treat. Biofilms are frequently polymicrobial, consisting of aerobic and anaerobic bacteria, as well as fungi and yeasts. The aim of this study was to evaluate the effects of a concentrated surfactant gel with antibacterial preservative agents (CSG) against wound relevant opportunistic pathogens, including an aerobic biofilm, anaerobic biofilm and multispecies biofilm. The CSG was added to a 48 h anaerobic biofilm of Bacteroides fragilis, a 24 h multispecies biofilm of Acinetobacter baumannii, Staphylococcus aureus and Staphylococcus epidermidis and a 24 h biofilm of Pseudomonas aeruginosa grown in an in vitro wound relevant environment. Following a contact time of 24 h with the CSG, the bacterial cell density of the biofilms was reduced by 2-4 log in comparison to an untreated control. The results demonstrate the ability of the CSG to disrupt wound relevant biofilms and support the use of the CSG in the clinic to treat wounds caused by biofilm related infections.}, } @article {pmid33430725, year = {2021}, author = {Bamunuarachchi, NI and Khan, F and Kim, YM}, title = {Bactericidal Activity of Sargassum aquifolium (Turner) C. Agardh against Gram-positive and Gram-negative Biofilm-forming Pathogenic Bacteria.}, journal = {Current pharmaceutical biotechnology}, volume = {22}, number = {12}, pages = {1628-1640}, doi = {10.2174/1389201022666210111122230}, pmid = {33430725}, issn = {1873-4316}, support = {NRF-2019R1A2C1087156//National Research Foundation of Korea (Ministry of Education)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Escherichia coli ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; *Sargassum ; Staphylococcus aureus ; }, abstract = {AIM: To study the bactericidal activity of crude ethanolic extract and fractionations obtained from Sargassum aquifolium (Turner) C. Agardh (brown algae) towards Gram-positive bacteria and Gram-negative biofilm-forming human pathogenic bacteria.

BACKGROUND: The increasing emergence of antibiotic-resistant bacteria in the hospital and community settings has led to the discovery of alternative strategies. Marine organisms are considered as one of the potential sources of diverse bioactive molecules against several biological activities. Hence, the algae, especially the marine brown algae were selected to evaluate its antibacterial activities towards biofilm-forming human pathogenic bacteria.

OBJECTIVE: To restrain the drug-resistant ability of pathogenic bacteria, we checked the extract of Sargassum aquifolium (Turner) C. Agardh (Phyophyceae) for the concerned bioactive compounds.

METHODS: Antibacterial activity towards both Gram-positive and Gram-negative bacteria was evaluated using disk diffusion and broth microdilution assays. Furthermore, the active compound present in the extracts was also identified using Gas-Chromatography-Mass Spectroscopy (GC-MS).

RESULTS: A total of 21 bioactive compounds were identified using GC-MS analysis with different chemical natures. The crude ethanolic extraction was fractionated sequentially according to the eluotropic series from less to extreme polar. The highest zone of inhibition was recorded for ethanolic extract on Listeria monocytogenes with a value of 38.00±0.17 mm and the lowest was 10.67±0.06 mm for ethyl acetate fraction on Pseudomonas aeruginosa. Ethyl acetate fractionate showed a higher effectivity than other fractionations. An MIC value of 256 μg/mL was recorded against Staphylococcus aureus and L. monocytogenes and 512 μg/mL against Escherichia coli and P. aeruginosa. Its ethanolic extract also showed synergism with oxytetracycline on S. aureus, L. monocytogenes, and E. coli. Furthermore, the same extracts also showed synergism with tetracycline on E. coli and with erythromycin on P. aeruginosa.

CONCLUSION: The present study reports the antibacterial activity of the S. aquifolium (Turner) C. Agardh extracts against human pathogenic bacteria. Furthermore, it also predicts the synergistic activity of selected antibiotic combinations against both selected Gram-positive and Gram-negative pathogenic bacteria.}, } @article {pmid33430377, year = {2021}, author = {Gómez-Molero, E and De-la-Pinta, I and Fernández-Pereira, J and Groß, U and Weig, M and Quindós, G and de Groot, PWJ and Bader, O}, title = {Candida parapsilosis Colony Morphotype Forecasts Biofilm Formation of Clinical Isolates.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {7}, number = {1}, pages = {}, pmid = {33430377}, issn = {2309-608X}, support = {ZabaldUz program//Universidad del País Vasco/ ; GIC15/78 IT-990-16//Consejería de Educación, Universidades e Investigación of Gobierno Vasco-Eusko Jaurlaritza/ ; SAF2013-47570-P, SAF2017-86188-P//Ministerio de Economía y Competitividad/ ; SAF2017-86188-P//European Regional Development Fund/ ; MC-ITN-606786//FP7-PEOPLE-2013-ITN-Marie-Curie Action: "Initial Training Networks"/ ; }, abstract = {Candida parapsilosis is a frequent cause of fungal bloodstream infections, especially in critically ill neonates or immunocompromised patients. Due to the formation of biofilms, the use of indwelling catheters and other medical devices increases the risk of infection and complicates treatment, as cells embedded in biofilms display reduced drug susceptibility. Therefore, biofilm formation may be a significant clinical parameter, guiding downstream therapeutic choices. Here, we phenotypically characterized 120 selected isolates out of a prospective collection of 215 clinical C. parapsilosis isolates, determining biofilm formation, major emerging colony morphotype, and antifungal drug susceptibility of the isolates and their biofilms. In our isolate set, increased biofilm formation capacity was independent of body site of isolation and not predictable using standard or modified European Committee on Antimicrobial Susceptibility Testing (EUCAST) drug susceptibility testing protocols. In contrast, biofilm formation was strongly correlated with the appearance of non-smooth colony morphotypes and invasiveness into agar plates. Our data suggest that the observation of non-smooth colony morphotypes in cultures of C. parapsilosis may help as an indicator to consider the initiation of anti-biofilm-active therapy, such as the switch from azole- to echinocandin- or polyene-based strategies, especially in case of infections by potent biofilm-forming strains.}, } @article {pmid33429924, year = {2021}, author = {Benzaid, C and Belmadani, A and Tichati, L and Djeribi, R and Rouabhia, M}, title = {Effect of Citrus aurantium L. Essential Oil on Streptococcus mutans Growth, Biofilm Formation and Virulent Genes Expression.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33429924}, issn = {2079-6382}, abstract = {In an oral cavity, dental caries, periodontal disease, and endodontic lesions are caused by well-known bacterial and fungal pathogens. Essential oils (EOs) have demonstrated antimicrobial activity suggesting their use for oral hygiene. The goal of this study was to evaluate the interaction of bitter orange flower (Citrus aurantium L.) essential oil with cariogenic bacteria Streptococcus mutans and human gingival epithelial cells. After extraction, the chemical composition of the essential oil was analyzed by gas chromatography, and its antimicrobial activity was evaluated against the growth and the expression of virulent genes in S. mutans. Finally, the effects of this essential oil on human gingival epithelial cell adhesion and growth were assessed using cell adhesion and proliferation assays. We showed that the major constituents of the tested essential oil were limonene, linalool, and β-ocimene. The essential oil reduced the growth of S. mutans, and decreased expression of comC, comD, comE, gtfB, gtfC, and gbpB genes. It should, however, be noted that essential oil at high concentration was toxic to gingival epithelial cells. Overall, this study suggests that C. aurantium L. essential oil could be used to prevent/control oral infections.}, } @article {pmid33429756, year = {2021}, author = {Ma, L and Xu, Y and Xu, X and Pan, Q and Xu, Y}, title = {Application of biomimetic double-layer biofilm stent in arthroscopic rotator cuff repair: A protocol of randomized controlled trial.}, journal = {Medicine}, volume = {100}, number = {1}, pages = {e23960}, pmid = {33429756}, issn = {1536-5964}, support = {No. 2018CFB769//Natural Science Foundation of Hubei Province/ ; }, mesh = {Aged ; *Biofilms ; Biometric Identification/*instrumentation/methods ; *Clinical Protocols ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Randomized Controlled Trials as Topic ; Rotator Cuff Injuries/*surgery ; Treatment Outcome ; }, abstract = {BACKGROUND: Rotator cuff injury is the most common cause of shoulder dysfunction. Despite the continuous advancement of surgical techniques, the incidence of re-tearing after rotator cuff repair is still high. The main reason is that it is difficult to reconstruct the normal tendon bone interface and the process is slow, and the application of tissue engineering technology can promote tendon and bone healing. This study will evaluate the effect of the bionic double membrane stent on the rotator cuff healing after arthroscopic rotator cuff repair.

METHODS: This is a prospective randomized controlled trial to study the effect of biomimetic double-layer biofilm stent on rotator cuff healing. Approved by the clinical research ethics committee of our hospital. The patients were randomly divided into 1 of 2 treatment options: (A) a biomimetic double-layer biofilm stent group and (B) a non-bionic dual-layer biofilm stent group. Observation indicators include: visual analog scale score, University of California Los Angeles score, American Shoulder & Elbow Surgeons score and Constant-Murley score. Data were analyzed using the statistical software package SPSS version 16.0 (Chicago, IL).

DISCUSSION: This study will evaluate and evaluate the effect of the bionic double-layer membrane stent on the rotator cuff healing after arthroscopic rotator cuff repair. The results of this experiment will provide new treatment ideas for promoting rotator cuff tendon bone healing.

OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/FWKD6.}, } @article {pmid33429277, year = {2021}, author = {Li, N and Li, X and Zhang, HJ and Fan, XY and Liu, YK}, title = {Microbial community and antibiotic resistance genes of biofilm on pipes and their interactions in domestic hot water system.}, journal = {The Science of the total environment}, volume = {767}, number = {}, pages = {144364}, doi = {10.1016/j.scitotenv.2020.144364}, pmid = {33429277}, issn = {1879-1026}, mesh = {*Anti-Bacterial Agents ; Biofilms ; Drug Resistance, Microbial/genetics ; Genes, Bacterial ; *Microbiota ; Water ; }, abstract = {This study aimed to explore the dynamics of microbial communities and antibiotic resistance genes (ARGs) during biofilm formation on polypropylene random (PPR), polyvinyl chloride and stainless steel pipes in domestic hot water system (DHWS), as well as their interactions. Full-scale classification was used to divide abundant and rare genera with 0.1% and 1% as the thresholds. The biofilm community structure presented a temporal pattern, which was mainly determined by conditionally rare or abundant taxa (CRAT) and conditionally rare taxa (CRT). The dynamics of microbial community during biofilm formation were observed, and the effect of pipe material on conditionally abundant taxa (CAT) and CRAT was greater than CRT and rare taxa (RT). CRAT showed the most complex internal associations and were identified as the core taxa. Notably, CRT and RT with low relative abundance, also played an important role in the network. For potential pathogens, 17 genera were identified in this study, and their total relative abundance was the highest (3.6-28.9%) in PPR samples. Enterococcus of CRAT was the dominant potential pathogen in young biofilms. There were 36 more co-exclusion patterns (140) observed between potential pathogens and nonpathogenic bacteria than co-occurrence (104). A total of 38 ARGs were predicted, and 109 negative and 165 positive correlations were detected between them. Some potential pathogens (Escherichia/Shigella and Burkholderia) and nonpathogenic bacteria (Meiothermus and Sphingopyxis) were identified as the possible hosts of ARGs. This study is helpful for a comprehensive understanding of the biofilm microbial community and ARGs, and provides a reference for the management and biosafety guarantee of newly-built DHWS.}, } @article {pmid33429234, year = {2021}, author = {Zhou, Y and Li, R and Guo, B and Yu, N and Xia, S and Liu, Y}, title = {Lumen air pressure (LAP) affecting greywater treatment in an oxygen-based membrane biofilm reactor (O2-MBfR).}, journal = {Chemosphere}, volume = {270}, number = {}, pages = {129541}, doi = {10.1016/j.chemosphere.2021.129541}, pmid = {33429234}, issn = {1879-1298}, mesh = {Air Pressure ; Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; *Oxygen ; *Waste Disposal, Fluid ; }, abstract = {Several technologies have been employed to treat greywater (GW) for domestic use. Aerobic biological treatment has achieved high efficiency, the main cost being the necessary source of oxygen (O2). This study explores the effects of lumen air pressure (LAP) on reactor performance and microbial community succession in an O2-based membrane biofilm reactor (O2-MBfR) treating GW. At high LAP (≥0.8 psi), the dissolved oxygen (DO) concentration inside the reactor was higher than 0.38 ± 0.02 mg/L, leading to removal efficiencies of 90%, 98%, and 80%, of total chemical oxygen demand, total linear alkylbenzene sulfonate (LAS), and total nitrogen, respectively. Lower LAP (<0.8 psi) led to a decrease in DO inside the system, and a less effective GW treatment. Low O2 pressure decreased organic biodegradation and ammoniation, and caused LAS accumulation in the biofilm, leading to the solubilization of extracellular polymeric substances and cell lysis. Comprehensive consideration of reactor performance and energy input, DO inside the MBfR at 0.38 ± 0.02 mg/L could be selected as the optimized condition for GW treatment. Microbial community analyses results also revealed that improved LAP was favorable for the enrichment of LAS-biodegradation related genus (Pseudomonas, Parvibaculum, Magnetospirillum, Clostridium, Zoogloea, Dechloromonas and Mycobacterium), nitrifiers (Nitrosomonas and Sphingomonas) and facultative microorganisms (Dechloromonas, Flavobacterium, Pseudomonas, Aeromonas and Zoogloea) that can carry out denitrification under relatively high DO conditions (>0.38 mg/L), but led to the reduction of the relative abundance of heterotrophs (Acidovorax, Thermomonas, Brevundimonas and Enterobacter) that are more sensitive towards high DO conditions.}, } @article {pmid33428914, year = {2021}, author = {Li, H and Li, Y and Guo, J and Song, Y and Hou, Y and Lu, C and Han, Y and Shen, X and Liu, B}, title = {Effect of calcinated pyrite on simultaneous ammonia, nitrate and phosphorus removal in the BAF system and the Fe[2+] regulatory mechanisms: Electron transfer and biofilm properties.}, journal = {Environmental research}, volume = {194}, number = {}, pages = {110708}, doi = {10.1016/j.envres.2021.110708}, pmid = {33428914}, issn = {1096-0953}, mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; Electron Transport ; Electrons ; Iron ; *Nitrates ; Nitrogen ; *Phosphorus ; Sulfides ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {To efficiently remove nitrogen and phosphorus from secondary effluent with low values of COD/TN, a novel biological aerated filter (BAF) utilizing calcined pyrite with a large specific surface area (SSA) and pore diameter (PD) was designed to address this challenge. From the perspective of nutrients removal performance, and the corresponding effluent total nitrogen (TN) and PO4[3-]-P in the calcined pyrite autotrophic denitrification (CPAD) process decreased from 40.21 to 1.07 mg/L to 1.22 and 0.14 mg/L, respectively. Furthermore, the nutrients removal kinetics analysis showed that the CPAD and pyrite autotrophic denitrification (PAD) processes could be fitted with Half-order and Zero-order reactions via kinetics analysis, respectively, indicating that the TN removal performance of CPAD processes was better than that of the PAD process. Moreover, CPAD combined with sulfur autotrophic denitrification (SAD) processes was fitted by First-order reaction, and the TN removal performance was further enhanced over the CPAD process. From the perspective of microregulation, Fe[2+] production in the PAD and CPAD processes could accelerate the electron transfer rate by increasing electron transport system activity (ETSA) and reducing electrochemical impedance spectroscopy (EIS). Moreover, Fe[2+] stimulated microbes to produce more proteins (PN) and C10-HSL, which improved biofilm stability and interspecific communication processes. Notably, nitrifiers and autotrophic denitrifiers were simultaneously enriched via detection of high-throughput sequencing of 16 S rRNA genes, which verified the feasibility of simultaneous nitrification and autotrophic denitrification. Therefore, BAF with calcined pyrite and sulfur as composite fillers have a considerable advantage in nutrients removal.}, } @article {pmid33428545, year = {2021}, author = {Arif, M and Sharaf, M and Samreen, and Khan, S and Chi, Z and Liu, CG}, title = {Chitosan-based nanoparticles as delivery-carrier for promising antimicrobial glycolipid biosurfactant to improve the eradication rate of Helicobacter pylori biofilm.}, journal = {Journal of biomaterials science. Polymer edition}, volume = {32}, number = {6}, pages = {813-832}, doi = {10.1080/09205063.2020.1870323}, pmid = {33428545}, issn = {1568-5624}, mesh = {*Anti-Infective Agents ; Biofilms ; *Chitosan ; Drug Carriers ; Glycolipids ; *Helicobacter pylori ; Humans ; *Nanoparticles ; Particle Size ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Driven by the need to find alternatives to control H. pylori infections, this work describes the development of chitosan-PMLA nanoparticulate systems as carriers for antimicrobial glycolipid. By using a simple ionic gelation method stable nanoparticle was obtained showing an encapsulation efficiency of 73.1 ± 1.3% and an average size of 217.0 ± 15.6 nm for rhamnolipids chitosan-PMLA nanoparticles (RL-CS-NPs). Glycolipid incorporation and particle size were correspondingly corroborated by FT-IR and TEM analysis. Rhamnolipids chitosan nanoparticles (RL-CS-NPs) presented the highest antimicrobial effect towards H. pylori (ATCC 26695) exhibiting a minimal inhibitory concentration of 132 µg/mL and a biofilm inhibition ability of 99%. Additionally, RL-CS-NPs did not interfere with human fibroblasts viability and proliferation under the tested conditions. The results revealed that the RL-CS-NPs were able to inhibit bacterial growth showing adequate cytocompatibility and might become, after additional studies, a valuable approach to fight H. pylori biofilm related-infections.}, } @article {pmid33428087, year = {2021}, author = {Houshmandyar, S and Eggleston, IM and Bolhuis, A}, title = {Biofilm-specific uptake of a 4-pyridone-based iron chelator by Pseudomonas aeruginosa.}, journal = {Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine}, volume = {34}, number = {2}, pages = {315-328}, pmid = {33428087}, issn = {1572-8773}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Iron Chelating Agents/*pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Pyridones/*pharmacology ; }, abstract = {Iron is an essential nutrient for virtually all microbes and limiting the concentration of available iron is a potential strategy to be used as an alternative to antibiotic treatment. In this study we analysed the antimicrobial activity of two chelators, specifically 3-hydroxy-1,2-dimethyl-4(1H)-pyridone (deferiprone, DFP), which is clinically approved for the treatment of iron overload disorders, and its 1,2-diethyl homologue, CP94. Both compounds showed moderate activity towards planktonically growing P. aeruginosa cells, and the mechanism of action of these chelators was indeed by limiting the amount of free iron. Surprisingly, the compounds behaved very differently when the cells were grown in biofilms. DFP also showed inhibitory effects on biofilm formation but in contrast, CP94 stimulated this process, in particular at high concentrations. We hypothesised that CP94 behaves as an iron carrier, which was confirmed by our observation that it had antimicrobial synergy with the toxic metals, gallium and copper. This suggests that P. aeruginosa produces a biofilm-specific transport protein that recognises CP94 but not the closely related compound DFP.}, } @article {pmid33427999, year = {2021}, author = {Zimba, S and Kumar, TS and Mohan, N and Rao, PH}, title = {Evaluation of various waste substrates for biofilm formation and subsequent use in aerobic packed-bed reactor for secondary treatment of domestic wastewater.}, journal = {World journal of microbiology & biotechnology}, volume = {37}, number = {2}, pages = {25}, pmid = {33427999}, issn = {1573-0972}, mesh = {Bacteria/growth & development ; Biodegradation, Environmental ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Immobilization ; Sewage/microbiology ; Wastewater/*microbiology ; *Water Purification ; }, abstract = {Immobilization of bacterial cells on suitable substrates is of utmost importance in the secondary treatment of wastewater using fixed-film reactors. Therefore, screening of efficient and cheaper materials for bacterial surface immobilization was carried out. Eleven waste materials were used as substrates, packed in a column, and bacterial surface immobilization was carried out using cow dung slurry/MLSS mixture. All the chosen substrates were screened for bacterial immobilization/biofilm formation by standard bacterial enumeration technique. The substrate with the highest biofilm-forming ability was used for secondary treatment of raw domestic wastewater. The results showed that high-density polyethylene and aluminium foil sheets have poor immobilizing characteristics with 2.2 × 10[8] and 2.4 × 10[8] CFU/cm[2] respectively, whereas jute fibres were observed to be the most efficient among the substrates with 5.1 × 10[23] CFU/cm[2]. The column packed with jute fibres was used for wastewater treatment. Various physico-chemical parameters were analyzed before and after treatment and there was a significant reduction in major parameters after treatment. The bacteria-immobilized jute fibres showed maximum immobilization potential and were highly efficient in wastewater treatment, and therefore these findings offer immense promise in the synthesis of composite polymers for bacterial immobilization and subsequent secondary treatment.}, } @article {pmid33427606, year = {2021}, author = {Brilhante, RSN and Paixão, GC and Pereira, VS and Oliveira, JS and Maciel, JM and Pereira-Neto, WA and Lima-Neto, RG and Castelo-Branco, DSCM and Cordeiro, RA and Sidrim, JJC and Rocha, MFG}, title = {Atypical chlamydoconidium-producing Trichophyton tonsurans strains from Ceará State, Northeast Brazil: investigation of taxonomy by phylogenetic analysis and biofilm susceptibility.}, journal = {Microbiology (Reading, England)}, volume = {167}, number = {2}, pages = {}, doi = {10.1099/mic.0.001018}, pmid = {33427606}, issn = {1465-2080}, mesh = {Antifungal Agents/*pharmacology ; Arthrodermataceae/*classification/cytology/drug effects/physiology ; Biofilms/*drug effects/growth & development ; Brazil ; DNA, Fungal/genetics ; DNA, Ribosomal/genetics ; Farnesol/pharmacology ; Fungal Proteins/genetics ; Humans ; Microbial Sensitivity Tests ; *Phylogeny ; Sequence Analysis, DNA ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Spores, Fungal/classification/cytology ; Terbinafine/pharmacology ; Tubulin/genetics ; }, abstract = {Chlamydoconidium-producing Trichophyton tonsurans strains isolated in Northeastern Brazil have morphological features different from the classic description of this dermatophyte species. This study investigated the phylogenetic relationship of chlamydoconidium-producing T. tonsurans strains isolated in Northeastern Brazil. Also, the effect of terbinafine and farnesol on mature biofilms of T. tonsurans strains was evaluated. The mass spectra of T. tonsurans strains were investigated by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The ITS and LSU loci regions of rDNA and the partial β-tubulin gene were sequenced and the phylogenetic tree was analysed. The effects of terbinafine and farnesol on mature T. tonsurans biofilms were evaluated through the analysis of metabolic activity, quantification of biomass and observation by scanning electron microscopy. MALDI-TOF MS spectra of the chlamydoconidium-producing T. tonsurans strains differed from the spectrum of the control strain (ATCC 28942), presenting an intense ion peak at m/z 4155 Da. Phylogenetic tree analysis showed that the chlamydoconidium-producing strains isolated in Northeastern Brazil are allocated to a single cluster, differing from strains isolated from other countries. As for mature T. tonsurans biofilms, farnesol reduced biomass and metabolic activity by 64.4 and 65.9 %, respectively, while terbinafine reduced the biomass by 66.5 % and the metabolic activity by 69 %. Atypical morphological characteristics presented by chlamydoconidium-producing T. tonsurans strains result from phenotypic plasticity, possibly for adaptation to environmental stressors. Also, farnesol had inhibitory activity against T. tonsurans biofilms, demonstrating this substance can be explored for development of promising anti-biofilm drugs against dermatophytes.}, } @article {pmid33427576, year = {2021}, author = {Ke, CL and Liao, YT and Lin, CH}, title = {MSS2 maintains mitochondrial function and is required for chitosan resistance, invasive growth, biofilm formation and virulence in Candida albicans.}, journal = {Virulence}, volume = {12}, number = {1}, pages = {281-297}, pmid = {33427576}, issn = {2150-5608}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*growth & development ; Candida albicans/drug effects/*genetics/growth & development/*pathogenicity ; Candidiasis/microbiology ; Chitosan/*pharmacology ; Fungal Proteins/genetics ; Gene Expression Regulation, Fungal ; Humans ; Hyphae/growth & development ; Male ; Membrane Proteins/genetics ; Mice ; Mice, Inbred ICR ; Mitochondria/genetics/*metabolism ; Mitochondrial Proteins/genetics ; Saccharomyces cerevisiae Proteins/genetics ; Virulence/genetics ; }, abstract = {Candida albicans is the most prevalent fungal pathogen in humans, particularly in immunocompromised patients. In this study, by screening a C. albicans mutant library, we first identified that the MSS2 gene, an ortholog of Saccharomyces cerevisiae MSS2 required for mitochondrial respiration, mediates chitosan resistance. Upon treatment with 0.2% chitosan, the growth of mss2Δ strains was strikingly impaired, and MSS2 expression was significantly repressed by chitosan. Furthermore, mss2Δ strains exhibited slow growth on medium supplemented with glycerol as the sole carbon source. Similar to the chitosan-treated wild-type strain, the mss2Δ strain exhibited a significantly impaired ATP production ability. These data suggest that an antifungal mechanism of chitosan against C. albicans acts by inhibiting MSS2 gene expression, leading to repression of mitochondrial function. Normal respiratory function is suggested to be required for fungal virulence. Interestingly, the mss2Δ mutant strains exhibited significantly impaired invasive ability in vitro and ex vivo but retained normal hyphal development ability in liquid medium. Furthermore, the MSS2 deletion strains could not form robust biofilms and exhibited significantly reduced virulence. Collectively, these results demonstrated that the antifungal effect of chitosan against C. albicans is mediated via inhibition of mitochondrial biogenesis. These data may provide another strategy for antifungal drug development via inhibition of fungal mitochondria.}, } @article {pmid33427232, year = {2021}, author = {Eick, S}, title = {Biofilm Models for the Evaluation of Dental Treatment.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {38-52}, doi = {10.1159/000510198}, pmid = {33427232}, issn = {1662-3843}, mesh = {*Biofilms ; *Dental Caries ; Enterococcus faecalis ; Humans ; Saliva ; Streptococcus mutans ; }, abstract = {When analyzing the activity of antimicrobial agents, it should be considered that microorganisms mainly occur in biofilms. Data obtained for planktonic bacteria cannot be transferred non-critically to biofilms. Biofilm models should consider both the relevant microorganisms and the conditions present in the environment. The selection of the model depends on the question to be answered. In dentistry, single species, multispecies, or microcosms originating from saliva or dental biofilm are used to culture biofilms. Microorganism selection depends on the focus of the study, for example caries biofilms mostly include Streptococcus mutans, an endodontic biofilm consists mostly of Enterococcus faecalis, and defined anaerobes are used in periodontal/peri-implant biofilms. In contrast to single-species biofilm models in medicine, where the lowest concentration of the antimicrobial that kills microorganisms is measured, the common analyzed variables are counts of colony-forming units or the percentage of dead bacteria determined by confocal laser scanning microscopy after applying a differentiating stain. All the models are helpful to evaluate new antimicrobial treatment options. Conclusions regarding the antimicrobial activity tendency of the therapeutics can be drawn. However, there are limitations of the model and ultimately a new therapy has to be proven in randomized controlled clinical trials.}, } @article {pmid33427231, year = {2021}, author = {Jentsch, HFR}, title = {Actual Concepts for Individual Interdental Biofilm Removal.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {74-79}, doi = {10.1159/000510202}, pmid = {33427231}, issn = {1662-3843}, mesh = {Biofilms ; Dental Devices, Home Care ; *Dental Plaque/prevention & control ; *Gingivitis/prevention & control ; Humans ; Toothbrushing ; }, abstract = {The intraoral biofilm requires mechanical removal due to its physical properties. When exposed to the biofilm, interdental areas need special devices to be used. The most effective ones and the first choice are interdental brushes. However, they may not be adequate in the case of very narrow interdental spaces. Despite the difficulties in handling, dental floss may have some advantage in subgingival cleaning. Data are present for gingivitis and periodontitis, but almost no information has been published on gingivally healthy individuals. With respect to interdental caries there is evidence that floss only has a protective value when used professionally and without sufficient fluoridation. There are no such data available on interdental brushes.}, } @article {pmid33427229, year = {2021}, author = {Bastendorf, KD and Strafela-Bastendorf, N and Lussi, A}, title = {Mechanical Removal of the Biofilm: Is the Curette Still the Gold Standard?.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {105-118}, doi = {10.1159/000510187}, pmid = {33427229}, issn = {1662-3843}, mesh = {Biofilms ; *Dental Plaque ; Humans ; *Periodontal Diseases/therapy ; Reference Standards ; Root Planing ; }, abstract = {The goal of modern periodontal therapy, both during the initial stages and during maintenance, is to create biologically acceptable tooth surfaces through sub- and supragingival cleaning, which enables binding of the connective tissue to the greatest extent possible. In past centuries, the focus of periodontal treatment was on the removal of the supposed cause of periodontal disease, the supra- and supragingival calculus and "infected" root cementum. The findings on the importance of biofilm1 (plaque) and the endogenous responses to biofilm metabolism have shifted the therapeutic focus to elimination of the biofilm. The importance of avoiding injury to the hard and soft dental tissue is nowadays of upmost importance. For classical scaling and root planing to remove mineralized deposits and "infected" cementum, only hand instruments were available in the past. The regular, long-term use of these tools is associated with changes in the hard and soft tooth tissues, and with pain and sensitivity experienced by the patient during and after treatment. Modern root-surface debridement primarily uses ultrasound systems to remove hard mineralized deposits. For biofilm management, air polishing devices with low-abrasive powders are increasingly gaining acceptance. With this new technology, biofilm management can now be performed much more effectively and efficiently, using materials more sparingly; this also causes less pain and discomfort for patients during and after treatment, and less fatigue for practitioners. The modern systems allow gentle, optimal biofilm management, whereas the traditional hand instruments (curettes, scalers) and classic rotating instruments used for polishing do not. Current knowledge suggests that these instruments are not best suited for biofilm management.}, } @article {pmid33427225, year = {2021}, author = {Arweiler, NB}, title = {Oral Mouth Rinses against Supragingival Biofilm and Gingival Inflammation.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {91-97}, doi = {10.1159/000510185}, pmid = {33427225}, issn = {1662-3843}, mesh = {Biofilms ; *Gingivitis/prevention & control ; Humans ; Inflammation ; *Mouthwashes/therapeutic use ; Oral Hygiene ; Toothbrushing ; }, abstract = {Caries and inflammatory periodontal diseases have a high prevalence worldwide. Although improvements in oral health status in our patients have been shown, there is still an increased demand for preventive measurements - especially in view of the systemic influence of the chronic disease periodontitis. The main focus of such measurements lies on an optimal biofilm management which can be divided into professional biofilm management and home care measurements. Since home care mechanical measurements such as toothbrushing and interdental cleaning are often insufficient or not on a regular basis, they can be supported by antibacterial agents which are able to inhibit or kill any oral microorganisms that remain. Besides a proven effect on plaque bacteria and gingival inflammation, agents should have a high substantivity in the oral cavity that outlast the short rinsing period. This chapter aims to present the background and rationale of using antibacterial mouth rinses, their common agents, to show sensible indications, and to evaluate the scientific evidence of their additional effect over toothbrushing alone.}, } @article {pmid33427222, year = {2021}, author = {Eick, S and Lussi, A}, title = {Arginine: A Weapon against Cariogenic Biofilm?.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {80-90}, doi = {10.1159/000510203}, pmid = {33427222}, issn = {1662-3843}, mesh = {Arginine ; Biofilms ; *Dental Caries/prevention & control ; Humans ; Streptococcus mutans ; Streptococcus sanguis ; }, abstract = {Untreated dental caries is the most prevalent disease worldwide. Development of caries is associated with the intake of sugar. The microorganisms utilize the sugar and create an acidic environment, which results in mineral loss. The appropriate use of fluoride is associated with a decline of caries. Another approach in preventing caries might be the increase of pH in dental plaque. During recent years, arginine has increasingly become the focus of interest. This is based on the fact that certain streptococci possess an arginine deiminase system (ADS) which metabolizes free arginine. In vivo, the incidence of caries was inversely correlated with ADS activity in saliva and dental plaque. ADS is highly active in Streptococcus gordonii and S. sanguinis, but is absent in S. sobrinus and S. mutans. In the presence of 1.5% L-arginine, S. gordonii and S. sanguinis, but not S. mutans and S. sobrinus, synthesize the metabolite citrulline and increase the pH of the environment.In defined multispecies biofilms consisting of ADS-positive and ADS-negative streptococci, supplementation with 1.5% arginine suppressed the growth of ADS-negative by favoring ADS-positive streptococci together with an increase in the pH of the environment. Evaluating the influence of daily manual removal of the biofilm in vitro by brushing with a commercial toothpaste containing fluoride and arginine resulted in less surface microhardness even when compared with a toothpaste with fluoride only. Recent studies clinically investigated the effect of using an arginine-containing dentifrice and reported a decrease of DMFS by about 10-20%.}, } @article {pmid33427221, year = {2021}, author = {Katagiri, H and Stuck, NJ and Arakawa, I and Nietzsche, S and Eick, S}, title = {In vitro Activity of Oral Health Care Products on Candida Biofilm Formation.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {214-226}, doi = {10.1159/000510194}, pmid = {33427221}, issn = {1662-3843}, mesh = {*Antifungal Agents/pharmacology ; Biofilms ; *Candida ; Candida albicans ; Delivery of Health Care ; Humans ; }, abstract = {The activity of mouthwash ingredients used in daily oral care (chlorhexidine digluconate, benzalkonium chloride, povidone iodine solution, tea tree oil) and of nystatin was evaluated not only on planktonic Candida albicans or C. glabrata, but also on the inhibition of biofilm formation. A microbroth dilution technique was used to determine the minimum inhibitory concentration of the substances against two laboratory strains and seven clinical isolates. Furthermore, a potential inhibition of biofilm formation of C. albicans or C. glabrata (single-species biofilm or mixed with two oral bacteria) was assessed. The results showed an activity of all tested substances against all C. albicans and C. glabratastrains. In the biofilm assays, a concentration-dependent effect of the substances was visible. However, a low concentration of povidone iodine solution and in particular of benzalkonium chloride seemed to increase the virulence of C. albicans. Most test substances affected both bacteria and yeasts in the mixed biofilms, only nystatin predominately reduced the yeasts. In conclusion, nystatin might be the drug of choice when exclusively preventing the colonization of Candida sp. in biofilms. The alternatives, benzalkonium chloride, povidone iodine solution, and tea tree oil, should be investigated further.}, } @article {pmid33427218, year = {2021}, author = {Müller, LK and Jungbauer, G and Jungbauer, R and Wolf, M and Deschner, J}, title = {Biofilm and Orthodontic Therapy.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {201-213}, doi = {10.1159/000510193}, pmid = {33427218}, issn = {1662-3843}, mesh = {Biofilms ; *Dental Caries/therapy ; *Gingivitis ; Humans ; Orthodontic Appliances/adverse effects ; Streptococcus mutans ; }, abstract = {Dental biofilms can cause major oral diseases like gingivitis, periodontitis, and caries. Orthodontic appliances promote supra- and subgingival biofilm accumulation, alter the oral microbiome, and hamper oral hygiene. Orthodontic treatment can be associated with adverse effects, such as enamel decalcification, gingivitis, and periodontal disease. The aim of this review is to summarize the changes in supra- and subgingival biofilm and periodontal tissues during and after orthodontic treatment. Studies have reported elevated levels of Streptococcus mutans and periodontopathogenic bacteria in patients undergoing orthodontic treatment. In general, the microbial changes and periodontal parameters decreased to pretreatment levels after appliance removal. Nevertheless, some adverse effects associated with orthodontic treatment are not reversible, such as enamel decalcifications caused by metabolic products of high levels of cariogenic bacteria. The evidence suggests that the roughness and constituents of the orthodontic materials influence the bacterial colonization. Therefore, several antibacterial orthodontic bonding systems, which show antibacterial effects in vitro, have been developed. The importance of adequate oral hygiene should be emphasized to all orthodontic patients. They should be frequently reminded and motivated to obtain a good oral hygiene. The evidence from the current literature suggests the safest way for orthodontic treatment in periodontally diseased patients may be after successful completion of the periodontal therapy. However, the exact time point needs to be better clarified in future studies.}, } @article {pmid33427216, year = {2021}, author = {Thurnheer, T and Paqué, PN}, title = {Biofilm Models to Study the Etiology and Pathogenesis of Oral Diseases.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {30-37}, doi = {10.1159/000510197}, pmid = {33427216}, issn = {1662-3843}, mesh = {*Biofilms ; Gingiva ; Humans ; *Mouth ; Plankton ; Reproducibility of Results ; }, abstract = {More than 700 microbial species inhabit the complex environment of the oral cavity. For years microorganisms have been studied in pure cultures, a highly artificial situation because microorganisms in natural habitats grow as complex ecologies, termed biofilms. These resemble multicellular organisms and are characterized by their overall metabolic activity upon multiple cellular interactions. Microorganisms in biofilms express different genes than their planktonic counterparts, resulting in higher resistance to antimicrobials, different nutritional requirements, or creation of a low redox potential allowing the growth of strictly anaerobic bacteria in the presence of oxygen. Multiple in vitro biofilm models have been described in the literature so far. The main emphasis here will be on multispecies biofilm batch culture models developed in Zurich. The standard 6-species supragingival biofilm model has been used to study basic aspects of oral biofilms such as structure, social behavior, and spatial distribution of microorganisms, or diffusion properties. Numerous parameters related to the inhibition of dental plaque were tested illustrating the high reliability of the model to predict the in vivo efficiency of antimicrobials. Modifications and advancements led to a 10-species subgingival model often combined with human gingival epithelial cells, as an integral part of the oral innate immune system, eliciting various cell responses ranging from cytokine production to apoptosis. In conclusion, biofilm models enable a multitude of questions to be addressed that cannot be studied with planktonic monocultures. The Zurich in vitro biofilm models are reproducible and reliable and may be used for basic studies, but also for application-oriented questions that could not be addressed using culture techniques. Oral biofilm research will certainly lead to a more realistic assessment of the role of microorganisms in the oral cavity in health and disease. In this respect, substantial progress has been made, but there is still more to explore.}, } @article {pmid33427214, year = {2021}, author = {Schultze, LB and Maldonado, A and Lussi, A and Sculean, A and Eick, S}, title = {The Impact of the pH Value on Biofilm Formation.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {19-29}, doi = {10.1159/000510196}, pmid = {33427214}, issn = {1662-3843}, mesh = {Biofilms ; *Dental Caries ; Humans ; Hydrogen-Ion Concentration ; Lactobacillus acidophilus ; *Streptococcus mutans ; }, abstract = {The pH value of a biofilm influences the pathogenesis and therapy of oral diseases such as caries and periodontitis. This study aimed to investigate the influence of different initial pH values on the microbial composition, bacterial counts, metabolic activity, and quantity of three defined biofilms representing oral health, caries, and periodontal disease. Respective bacterial suspensions in the nutrient broth were initially adjusted to pH values between 5 and 8. Then biofilms were cultured on polystyrene surfaces coated with a proteinaceous solution for 2 h ("healthy" biofilm), 6 h ("healthy," and "cariogenic" biofilms), 24 h ("cariogenic," and "periodontitis" biofilms), and 48 h ("periodontitis" biofilm). In all biofilms, total bacterial counts were lower at an initial pH of 5 or 5.5 than at higher pH values. In the biofilm representing caries, the percentage of cariogenic bacteria (Streptococcus mutans, S. sobrinus, Lactobacillus acidophilus) was higher at a low pH, the metabolic activity was highest at pH 6-6.5, and biofilm mass was greatest at pH 7-7.5. In the biofilm representing periodontitis, the percentage of Porphyromonas gingivalis increased with the pH. Also, the metabolic activity was highest at pH 8, whereas mass had the highest value at pH 7. In conclusion, the initial pH value influences biofilm formation. In particular, metabolic activity and the amount of bacteria associated with disease correlated with the respective pH known to be of importance in the development of caries (relatively low pH) and periodontitis (higher pH). Modifying the pH level in oral biofilms might be an alternative concept in (primary) prevention and treatment, not only of caries but also of periodontitis.}, } @article {pmid33427212, year = {2021}, author = {Cvikl, B and Lussi, A}, title = {Supragingival Biofilm: Toothpaste and Toothbrushes.}, journal = {Monographs in oral science}, volume = {29}, number = {}, pages = {65-73}, doi = {10.1159/000510201}, pmid = {33427212}, issn = {1662-3843}, mesh = {Adult ; Biofilms ; Child ; *Dental Plaque ; *Gingivitis ; Humans ; Toothbrushing ; Toothpastes ; }, abstract = {The formation of a physiological biofilm cannot be avoided under normal circumstances. However, the consequences of a supragingivally located biofilm, such as caries, gingivitis and, as a further effect, periodontitis, are relatively easy to avoid. The simplest and most common method used worldwide for the elimination of biofilm is periodic mechanical removal using a toothbrush or similar tools, such as chewing sticks or woods. This method was already used in ancient Egypt, and is still being used today, albeit advanced and improved with the help of toothpastes. Here we give a summary of the most common toothbrushes, highlighting their advantages and disadvantages. Furthermore, we provide an overview of the most common toothpastes, their ingredients, and functions. In addition, the ingredients will be critically evaluated and recommendations given for the use or non-use of certain ingredients for different target groups, such as children, healthy adults, or patients with special needs.}, } @article {pmid33424814, year = {2020}, author = {Smith, V and Josefsen, M and Lindbäck, T and Hegna, IK and Finke, S and Tourasse, NJ and Nielsen-LeRoux, C and Økstad, OA and Fagerlund, A}, title = {MogR Is a Ubiquitous Transcriptional Repressor Affecting Motility, Biofilm Formation and Virulence in Bacillus thuringiensis.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {610650}, pmid = {33424814}, issn = {1664-302X}, abstract = {Flagellar motility is considered an important virulence factor in different pathogenic bacteria. In Listeria monocytogenes the transcriptional repressor MogR regulates motility in a temperature-dependent manner, directly repressing flagellar- and chemotaxis genes. The only other bacteria known to carry a mogR homolog are members of the Bacillus cereus group, which includes motile species such as B. cereus and Bacillus thuringiensis as well as the non-motile species Bacillus anthracis, Bacillus mycoides and Bacillus pseudomycoides. Furthermore, the main motility locus in B. cereus group bacteria, carrying the genes for flagellar synthesis, appears to be more closely related to L. monocytogenes than to Bacillus subtilis, which belongs to a separate phylogenetic group of Bacilli and does not carry a mogR ortholog. Here, we show that in B. thuringiensis, MogR overexpression results in non-motile cells devoid of flagella. Global gene expression profiling showed that 110 genes were differentially regulated by MogR overexpression, including flagellar motility genes, but also genes associated with virulence, stress response and biofilm lifestyle. Accordingly, phenotypic assays showed that MogR also affects cytotoxicity and biofilm formation in B. thuringiensis. Overexpression of a MogR variant mutated in two amino acids within the putative DNA binding domain restored phenotypes to those of an empty vector control. In accordance, introduction of these mutations resulted in complete loss in MogR binding to its candidate flagellar locus target site in vitro. In contrast to L. monocytogenes, MogR appears to be regulated in a growth-phase dependent and temperature-independent manner in B. thuringiensis 407. Interestingly, mogR was found to be conserved also in non-motile B. cereus group species such as B. mycoides and B. pseudomycoides, which both carry major gene deletions in the flagellar motility locus and where in B. pseudomycoides mogR is the only gene retained. Furthermore, mogR is expressed in non-motile B. anthracis. Altogether this provides indications of an expanded set of functions for MogR in B. cereus group species, beyond motility regulation. In conclusion, MogR constitutes a novel B. thuringiensis pleiotropic transcriptional regulator, acting as a repressor of motility genes, and affecting the expression of a variety of additional genes involved in biofilm formation and virulence.}, } @article {pmid33424412, year = {2021}, author = {Elbehiry, A and Marzouk, E and Moussa, IM and Dawoud, TM and Mubarak, AS and Al-Sarar, D and Alsubki, RA and Alhaji, JH and Hamada, M and Abalkhail, A and A Hemeg, H and Zahran, RN}, title = {Acinetobacter baumannii as a community foodborne pathogen: Peptide mass fingerprinting analysis, genotypic of biofilm formation and phenotypic pattern of antimicrobial resistance.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {1}, pages = {1158-1166}, pmid = {33424412}, issn = {1319-562X}, abstract = {Acinetobacter baumannii (A. baumannii) is one of the most common Gram-negative pathogens that represent a major threat to human life. Because the prevalence of Multidrug-resistant biofilm-forming A. baumannii is increasing all over the world, this may lead to outbreaks of hospital infections. Nonetheless, the role of raw meat as a reservoir for A. baumannii remains unclear. Here our research was aimed to exhibit the frequency, precise identification, and genotyping of biofilm-related genes as well as antimicrobial resistance of A. baumannii isolates of raw meat specimens. Fifty-five A. baumannii strains were recovered from 220 specimens of different animal meat and then identified by Peptide Mass Fingerprinting Technique (PMFT). All identified isolates were genotyped by the qPCR method for the existence of biofilm-related genes (ompA, bap, blaPER-1, csuE, csgA, and fimH). In addition, the antimicrobial resistance against A. baumannii was detected by the Kirby-Bauer method. Based on our findings, the frequency rate of 55 A. baumannii isolates was 46.55%, 32.50%, 15.00%, and 9.68% of sheep, chicken, cow, and camel raw meat samples, respectively. The PMFT was able to identify all strains by 100%. the percentages of csuE, ompA, blaPER-1, bap, and csgA genes in biofilm and non-biofilm producer A. baumannii were 72.73%, 60%, 58.2%, 52.74%, and 25.45%, respectively. In contrast, the fimH was not detected in all non-biofilm and biofilm producer strains. The ompA, bap, blaPER-1, csgA were detected only in biofilm-producing A. baumannii isolates. The maximum degree of resistance was observed against amoxicillin/clavulanic acid (89.10%), gentamicin (74.55%), tetracycline (72.73%), ampicillin (65.45%), and tobramycin (52.73%). In conclusion, our investigation demonstrated the high incidence of multi-drug resistant A. baumannii in raw meat samples, with a high existence of biofilm-related virulence genes of ompA, bap, blaPER-1, csgA. Therefore, it has become necessary to take the control measures to limit the development of A. baumannii.}, } @article {pmid33424397, year = {2021}, author = {Alfarrayeh, I and Fekete, C and Gazdag, Z and Papp, G}, title = {Propolis ethanolic extract has double-face in vitro effect on the planktonic growth and biofilm formation of some commercial probiotics.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {1}, pages = {1033-1039}, pmid = {33424397}, issn = {1319-562X}, abstract = {This study investigated the in vitro effect of propolis ethanolic extract (PEE) on planktonic growth and biofilm forming abilities of five commercial probiotics (Enterol, Protexin, Normaflore, BioGaia and Linex). Broth microdilution method was used to investigate the susceptibility of the microbes of five commercial probiotics to PEE. Crystal violet assay was used for the quantitative assessment of biofilm formation and mature biofilm eradication tests. Effect of PEE on autoaggregation ability and swarming motility of Normaflore microbes was determined. Planktonic forms of probiotics showed varied susceptibilities with minimal inhibitory concentration values in the range of 100-800 µg/mL of PEE. However, low PEE concentrations significantly enhanced the planktonic growth of Linex and BioGaia microbes. Biofilm studies revealed that Enterol and Protexin were non-biofilm formers, while BioGaia, Linex and Normaflore showed weak biofilms, which were inhibited by 12.5, 25, and 800 µg/mL of PEE, respectively. PEE revealed double-face effect on the biofilms of Normaflore and Linex, which were enhanced at low concentrations of PEE and inhibited at higher concentrations. Interestingly, Normaflore biofilms were shifted from weak to strong biofilms at low PEE concentrations (12.5, 25, and 50 µg/mL). In conclusion, PEE has strain dependent controversial effects on the planktonic growth and biofilm forming ability of the tested probiotics, although high concentrations have inhibitory effect on all of them, low concentrations may have strain dependent prebiotic effect.}, } @article {pmid33424369, year = {2021}, author = {Haque, MM and Haque, MA and Mosharaf, MK and Marcus, PK}, title = {Decolorization, degradation and detoxification of carcinogenic sulfonated azo dye methyl orange by newly developed biofilm consortia.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {1}, pages = {793-804}, pmid = {33424369}, issn = {1319-562X}, abstract = {Metabolites of azo dyes are often carcinogenic, teratogenic, mutagenic and recalcitrant in nature. In this study, four biofilm consortia such as C1 (Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304), C2 (Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201), C3 (E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401), and C4 (E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were applied to degrade and detoxify methyl orange (MO), a carcinogenic, sulfonated mono azo dye, used in textile dyeing industry worldwide. The consortia of C1, C2, C3 and C4 showed 97.30, 98.75, 99.51 and 99.29% decolorization, respectively in yeast extract peptone (YEP) broth containing 200 mg L[-1] MO within 60 h of incubation in static condition. The optimum pH and temperature for decolorization was 7.0 and 28 °C, respectively. Some divalent metal ions including Mg[2+], Ca[2+], Zn[2+] and Mn[2+] could stimulate MO decolorization. UV-Vis spectral analysis showed that the absorption peak at 465 nm originated from the azo (N[bond, double bond]N) bond was completely disappeared within 60 h of incubation. Fourier transform infrared spectroscopy (FTIR) results also revealed that several major peaks including azo bond peak at 1602.6 cm[-1] are completely or partly vanished, deformed or shifted. Activities of azoreductase, NADH-DCIP reductase and laccase were significantly increased in the bacterial cells within 60 h of incubation in comparison to that of control (0 h). The chemical oxygen demand was incredibly reduced by 85.37 to 91.44% by these consortia. Accordingly, plant (wheat seed germination) and microbial (growth of the plant probiotic bacteria such as Pseudomonas cedrina ESR12 and Bacillus cereus ESD3 on biodegraded products) toxicity studies showed that biodegraded products of MO are non-toxic. Thus, all these consortia can be utilized in bioremediation of MO from wastewater for safe disposal into environment. To our knowledge, this is the first report on degradation and detoxification of MO from wastewater by bacterial biofilm consortia.}, } @article {pmid33424310, year = {2021}, author = {Khaled, JM and Alyahya, SA and Chenthis Kanisha, C and Alharbi, NS and Kadaikunnan, S and Ramachandran, G and Alanzi, KF and Rajivgandhi, G and Vimala, R and Manoharan, N}, title = {Anti-biofilm activity of LC-MS based Solanum nigrum essential oils against multi drug resistant biofilm forming P. mirabilis.}, journal = {Saudi journal of biological sciences}, volume = {28}, number = {1}, pages = {302-309}, pmid = {33424310}, issn = {1319-562X}, abstract = {Urinary tract infections are second most important diseases worldwide due to the increased amount of antibiotic resistant microbes. Among the Gram negative bacteria, P. mirabilis is the dominant biofilm producer in urinary tract infections next to E. coli. Biofilm is a process that produced self-matrix of more virulence pathogens on colloidal surfaces. Based on the above fact, this study was concentrated to inhibit the P. mirabilis biofilm formation by various in-vitro experiments. In the current study, the anti-biofilm effect of essential oils was recovered from the medicinal plant of Solanum nigrum, and confirmed the available essential oils by liquid chromatography-mass spectroscopy analysis. The excellent anti-microbial activity and minimum biofilm inhibition concentration of the essential oils against P. mirabilis was indicated at 200 µg/mL. The absence of viability and altered exopolysaccharide structure of treated cells were showed by biofilm metabolic assay and phenol-sulphuric acid method. The fluorescence differentiation of P. mirabilis treated cells was showed with more damages by confocal laser scanning electron microscope. Further, more morphological changes of essential oils treated cells were differentiated from normal cells by scanning electron microscope. Altogether, the results were reported that the S. nigrum essential oils have anti-biofilm ability.}, } @article {pmid33423380, year = {2021}, author = {Cai, L and Jia, H and He, L and Wei, X and Feng, H and Fan, G and Ma, X and Ma, G and Sun, X}, title = {The photocatalytic antibacterial molecular mechanisms towards Pseudomonas syringae pv. tabaci by g-C3 N4 nanosheets: insights from the cytomembrane, biofilm and motility disruption.}, journal = {Pest management science}, volume = {77}, number = {5}, pages = {2302-2314}, doi = {10.1002/ps.6257}, pmid = {33423380}, issn = {1526-4998}, support = {31670148//the National Natural Science Foundation of China/ ; 31870147//the National Natural Science Foundation of China/ ; XDJK2020B064//the Fundamental Research Funds for the Central Universities/ ; A20201NY02-1306//the science and technology projects of Chongqing Company of China Tobacco Corporation/ ; B20202NY1338//the science and technology projects of Chongqing Company of China Tobacco Corporation/ ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Movement ; Light ; *Pseudomonas syringae ; }, abstract = {BACKGROUND: Antibacterial photocatalytic therapy has been employed as a promising strategy to combat antibiotic-resistant bacteria in the water disinfection field, especially some non-metal inorganic nanomaterials. However, their antibacterial activities on plant phytopathogens are poorly understood. Here, the photocatalytic antibacterial mechanism of the urea-synthesized graphitic carbon nitride nanosheets (g-C3 N4 nanosheets) against Pseudomonas syringae pv. tabaci was systematically investigated in vitro and in vivo.

RESULTS: The g-C3 N4 nanosheets exhibited remarkable concentration-dependent and irradiation-time-dependent antibacterial properties, and the 0.5 mg mL[-1] concentration ameliorated tobacco wildfire disease in host plants. Specifically, under visible irradiation, g-C3 N4 nanosheets produced numerous reactive oxygen species (ROS), supplementing the plentiful extracellular and intracellular ROS in bacteria. After exposing light-induced g-C3 N4 nanosheets for 1 h, 500 genes were differentially expressed, according to transcriptome analyses. Notably, the expression of genes related 'antioxidant activity' and 'membrane transport' was sharply upregulated, and those related to 'bacterial chemotaxis', 'biofilm formation', 'energy metabolism' and 'cell motility' were downregulated. After exposure for over 2 h, the longer-time pressure on the target bacteria cause the decreased biofilm formation and flagellum motility, further injuring the cell membranes leading to cytoplasm leakage and damaged DNA, eventually resulting in the bacterial death. Concomitantly, the attachment of g-C3 N4 nanosheets was a synergistic physical antibacterial pathway. The infection capacity assessment also supported the earlier supposition.

CONCLUSION: These results provide novel insights into the photocatalytic antibacterial mechanisms of g-C3 N4 nanosheets at the transcriptome level, which are expected to be useful for dissecting the response pathways in antibacterial activities and for improving g-C3 N4 -based photocatalysts practices in plant disease control. © 2021 Society of Chemical Industry.}, } @article {pmid33421727, year = {2021}, author = {Krsmanovic, M and Biswas, D and Ali, H and Kumar, A and Ghosh, R and Dickerson, AK}, title = {Hydrodynamics and surface properties influence biofilm proliferation.}, journal = {Advances in colloid and interface science}, volume = {288}, number = {}, pages = {102336}, doi = {10.1016/j.cis.2020.102336}, pmid = {33421727}, issn = {1873-3727}, mesh = {Bacteria ; *Biofilms ; Cell Proliferation ; Humans ; *Hydrodynamics ; Surface Properties ; }, abstract = {A biofilm is an interface-associated colloidal dispersion of bacterial cells and excreted polymers in which microorganisms find protection from their environment. Successful colonization of a surface by a bacterial community is typically a detriment to human health and property. Insight into the biofilm life-cycle provides clues on how their proliferation can be suppressed. In this review, we follow a cell through the cycle of attachment, growth, and departure from a colony. Among the abundance of factors that guide the three phases, we focus on hydrodynamics and stratum properties due to the synergistic effect such properties have on bacteria rejection and removal. Cell motion, whether facilitated by the environment via medium flow or self-actuated by use of an appendage, drastically improves the survivability of a bacterium. Once in the vicinity of a stratum, a single cell is exposed to near-surface interactions, such as van der Waals, electrostatic and specific interactions, similarly to any other colloidal particle. The success of the attachment and the potential for detachment is heavily influenced by surface properties such as material type and topography. The growth of the colony is similarly guided by mainstream flow and the convective transport throughout the biofilm. Beyond the growth phase, hydrodynamic traction forces on a biofilm can elicit strongly non-linear viscoelastic responses from the biofilm soft matter. As the colony exhausts the means of survival at a particular location, a set of trigger signals activates mechanisms of bacterial release, a life-cycle phase also facilitated by fluid flow. A review of biofilm-relevant hydrodynamics and startum properties provides insight into future research avenues.}, } @article {pmid33421708, year = {2021}, author = {Zhang, G and Yang, Y and Shi, J and Yao, X and Chen, W and Wei, X and Zhang, X and Chu, PK}, title = {Near-infrared light II - assisted rapid biofilm elimination platform for bone implants at mild temperature.}, journal = {Biomaterials}, volume = {269}, number = {}, pages = {120634}, doi = {10.1016/j.biomaterials.2020.120634}, pmid = {33421708}, issn = {1878-5905}, mesh = {*Biofilms ; Infrared Rays ; *Osteogenesis ; Phototherapy ; Prospective Studies ; Temperature ; }, abstract = {Light-triggered therapy is a prospective method to combat implant-associated infection but near-infrared I (NIR-I) light has insufficient penetrating ability in tissues and local hyperthermia induced by the photothermal treatment may destroy surrounding healthy tissues. Herein, a near-infrared II (NIR-II) phototherapy system composed of upconversion elements doped titanium dioxide nanorods (TiO2 NRs)/curcumin (Cur)/hyaluronic acid (HA)/bone morphogenetic protein-2 (BMP-2) is designed for biomedical titanium and demonstrated to overcome the above hurdles simultaneously. Incorporation of F, Yb, and Ho not only improves the photocatalytic ability, but also renders the implants with the upconversion capability, so that the NRs can generate enough reactive oxygen species (ROS) when irradiated by the NIR-II laser. Furthermore, the combined actions of quorum sensing inhibitors, ROS, and physical puncture by NRs eliminate Staphylococcus aureus biofilms on titanium rapidly at a mild temperature of 45 °C by only requiring irradiation with the 1060 nm laser for only 15 min in vitro and in vivo. The presence of Cur mitigates the immune response and BMP-2 improves osteogenic differentiation, thus accelerating new bone formation. This low-temperature NIR-II light-triggered antibacterial platform has large potential in combating deep-tissue infection in clinical applications.}, } @article {pmid33421102, year = {2021}, author = {Wunnoo, S and Paosen, S and Lethongkam, S and Sukkurd, R and Waen-Ngoen, T and Nuidate, T and Phengmak, M and Voravuthikunchai, SP}, title = {Biologically rapid synthesized silver nanoparticles from aqueous Eucalyptus camaldulensis leaf extract: Effects on hyphal growth, hydrolytic enzymes, and biofilm formation in Candida albicans.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {4}, pages = {1597-1611}, doi = {10.1002/bit.27675}, pmid = {33421102}, issn = {1097-0290}, mesh = {Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Eucalyptus/*chemistry ; Gene Expression Regulation, Fungal/drug effects ; Metal Nanoparticles/*chemistry ; Plant Extracts/*chemistry ; Plant Leaves/*chemistry ; *Silver/chemistry/pharmacology ; }, abstract = {Bionanotechnology has increasingly gained attention in biomedical fields as antifungal and antibiofilm agents. In this study, biosynthesized silver nanoparticles (bio-AgNPs) using aqueous Eucalyptus camaldulensis leaf extract were successfully performed by a one-step green approach. Spherical-shaped nanoparticles, approximately 8.65 nm, exhibited noncytotoxicity to erythrocytes, HeLa, and HaCaT cells. The synthesized nanoparticles showed strong fungicidal activity ranging from 0.5 to 1 µg/ml. The nanoparticles affected Candida adhesion and invasion into host cells by reduced germ tube formation and hydrolytic enzyme secretion. Inhibitory effects of bio-AgNPs on Candida biofilms were evaluated by the prevention of yeast-to-hyphal transition. A decrease in cell viability within mature biofilm demonstrated the ability of bio-AgNPs to penetrate into the extracellular matrix and destroy yeast cell morphology, leading to cell death. Molecular biology study on biofilms confirmed downregulation in the expression of genes ALS3, HWP1, ECE1, EFG1, TEC1, ZAP1, encoding hyphal growth and biofilm development and PLB2, LIP9, SAP4, involved in hydrolytic enzymes. In addition to candida treatment, the bio-AgNPs could be applied as an antioxidant to protect against oxidative stress-related human diseases. The findings concluded that bio-AgNPs could be used as an antifungal agent for candida treatment, as well as be incorporated in medical devices to prevent biofilm formation.}, } @article {pmid33420225, year = {2021}, author = {Sotozono, M and Kuriki, N and Asahi, Y and Noiri, Y and Hayashi, M and Motooka, D and Nakamura, S and Machi, H and Iida, T and Ebisu, S}, title = {Impacts of sleep on the characteristics of dental biofilm.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {138}, pmid = {33420225}, issn = {2045-2322}, mesh = {Adult ; Bacteria/genetics/growth & development/isolation & purification ; *Biofilms ; Dental Caries/microbiology/*physiopathology ; Female ; Humans ; Male ; Mouth/microbiology ; Periodontal Diseases/microbiology/*physiopathology ; *Sleep ; }, abstract = {Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease. Because bacterial numbers rapidly increase in saliva during sleep, oral care before sleeping is recommended for the prevention of chronic oral diseases. However, temporal circadian changes in the quantity and quality of dental biofilms are poorly understood. This study aimed to investigate the impacts of sleeping on dental biofilm amounts and compositions by using an in situ model. The use of this in situ model enabled us to investigate dental biofilm formed in the oral cavity and to perform a quantitative analysis. Subjects began wearing oral splints in the morning or before sleeping, and biofilm samples were collected at 8, 16, and 24 h after the subjects began wearing oral splints; these samples were then used in various experiments. No significant changes in the numbers of biofilm-forming bacteria were caused by sleep. However, the relative abundances of genera related to periodontitis (i.e., Fusobacterium and Prevotella) increased after awakening. In conclusion, the numbers of biofilm-forming bacteria were not affected by sleep, and the abundances of obligate anaerobes increased after sleep. This research may aid in defining efficacious preventive oral care.}, } @article {pmid33419769, year = {2021}, author = {Aldrich, AL and Horn, CM and Heim, CE and Korshoj, LE and Kielian, T}, title = {Transcriptional Diversity and Niche-Specific Distribution of Leukocyte Populations during Staphylococcus aureus Craniotomy-Associated Biofilm Infection.}, journal = {Journal of immunology (Baltimore, Md. : 1950)}, volume = {206}, number = {4}, pages = {751-765}, pmid = {33419769}, issn = {1550-6606}, support = {P20 GM103427/GM/NIGMS NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; P30 GM110768/GM/NIGMS NIH HHS/United States ; R01 NS107369/NS/NINDS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; *Craniotomy ; Female ; Granulocytes/*immunology/pathology ; Male ; Mice ; Myeloid-Derived Suppressor Cells/*immunology/pathology ; Staphylococcal Infections/*immunology/pathology ; Staphylococcus aureus/*physiology ; Transcription, Genetic/*immunology ; }, abstract = {Neurosurgery for brain tumor resection or epilepsy treatment requires a craniotomy to gain access to the brain. Despite prophylactic measures, infectious complications occur at a frequency of 1-3%, with approximately half caused by Staphylococcus aureus (S. aureus) that forms a biofilm on the bone flap and is recalcitrant to antibiotics. Using single-cell RNA sequencing in a mouse model of S. aureus craniotomy infection, this study revealed the complex transcriptional heterogeneity of resident microglia and infiltrating monocytes in the brain, in addition to transcriptionally diverse granulocyte subsets in the s.c. galea and bone flap. In the brain, trajectory analysis identified the transition of microglia from a homeostatic/anti-inflammatory to proinflammatory and proliferative populations, whereas granulocytes in the brain demonstrated a trajectory from a granulocyte myeloid-derived suppressor cell (MDSC)-like phenotype to a small population of mature polymorphonuclear neutrophils (PMNs). In the galea, trajectory analysis identified the progression from two distinct granulocyte-MDSC-like populations to PMN clusters enriched for IFN signaling and cell cycle genes. Based on their abundance in the galea and bone flap, PMNs and MDSCs were depleted using anti-Ly6G, which resulted in increased bacterial burden. This revealed a critical role for PMNs in S. aureus containment because MDSCs were found to attenuate PMN antibacterial activity, which may explain, in part, why craniotomy infection persists in the presence of PMN infiltrates. These results demonstrate the existence of a transcriptionally diverse leukocyte response that likely influences the chronicity of S. aureus craniotomy infection.}, } @article {pmid33419303, year = {2020}, author = {Lacerna, NM and Ramones, CMV and Robes, JMD and Picart, MRD and Tun, JO and Miller, BW and Haygood, MG and Schmidt, EW and Salvador-Reyes, LA and Concepcion, GP}, title = {Inhibition of Biofilm Formation by Modified Oxylipins from the Shipworm Symbiont Teredinibacter turnerae.}, journal = {Marine drugs}, volume = {18}, number = {12}, pages = {}, pmid = {33419303}, issn = {1660-3397}, support = {U19TW008163//Fogarty International Center, National Institute of Health/ ; }, mesh = {Animals ; Biofilms/*drug effects/growth & development ; Bivalvia ; *Gammaproteobacteria/chemistry ; Microbial Sensitivity Tests/methods ; Oxylipins/isolation & purification/*pharmacology ; Symbiosis/*drug effects/physiology ; }, abstract = {The bioactivity-guided purification of the culture broth of the shipworm endosymbiont Teredinibacter turnerae strain 991H.S.0a.06 yielded a new fatty acid, turneroic acid (1), and two previously described oxylipins (2-3). Turneroic acid (1) is an 18-carbon fatty acid decorated by a hydroxy group and an epoxide ring. Compounds 1-3 inhibited bacterial biofilm formation in Staphylococcus epidermidis, while only 3 showed antimicrobial activity against planktonic S. epidermidis. Comparison of the bioactivity of 1-3 with structurally related compounds indicated the importance of the epoxide moiety for selective and potent biofilm inhibition.}, } @article {pmid33418930, year = {2021}, author = {Batoni, G and Maisetta, G and Esin, S}, title = {Therapeutic Potential of Antimicrobial Peptides in Polymicrobial Biofilm-Associated Infections.}, journal = {International journal of molecular sciences}, volume = {22}, number = {2}, pages = {}, pmid = {33418930}, issn = {1422-0067}, mesh = {Antimicrobial Cationic Peptides/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Coinfection/drug therapy/microbiology/*pathology ; Cystic Fibrosis/complications/pathology ; Humans ; Lung Diseases/etiology/microbiology/pathology ; Pseudomonas aeruginosa/physiology ; Sepsis/drug therapy/etiology/pathology ; Staphylococcus aureus/physiology ; }, abstract = {It is widely recognized that many chronic infections of the human body have a polymicrobial etiology. These include diabetic foot ulcer infections, lung infections in cystic fibrosis patients, periodontitis, otitis, urinary tract infections and even a proportion of systemic infections. The treatment of mixed infections poses serious challenges in the clinic. First, polymicrobial communities of microorganisms often organize themselves as biofilms that are notoriously recalcitrant to antimicrobial therapy and clearance by the host immune system. Secondly, a plethora of interactions among community members may affect the expression of virulence factors and the susceptibility to antimicrobials of individual species in the community. Therefore, new strategies able to target multiple pathogens in mixed populations need to be urgently developed and evaluated. In this regard, antimicrobial or host defense peptides (AMPs) deserve particular attention as they are endowed with many favorable features that may serve to this end. The aim of the present review is to offer a comprehensive and updated overview of studies addressing the therapeutic potential of AMPs in mixed infections, highlighting the opportunities offered by this class of antimicrobials in the fight against polymicrobial infections, but also the limits that may arise in their use for this type of application.}, } @article {pmid33418435, year = {2021}, author = {Wang, Y and Samaranayake, LP and Dykes, GA}, title = {Tea extracts modulate oral biofilm development by altering bacterial hydrophobicity and aggregation.}, journal = {Archives of oral biology}, volume = {122}, number = {}, pages = {105032}, doi = {10.1016/j.archoralbio.2020.105032}, pmid = {33418435}, issn = {1879-1506}, mesh = {Biofilms/*drug effects ; Durapatite ; Glass ; Hydrophobic and Hydrophilic Interactions ; Plant Extracts/*pharmacology ; Stainless Steel ; Streptococcus mutans/*drug effects ; Tea/*chemistry ; Titanium ; }, abstract = {OBJECTIVES: This study aims to investigate the effects of tea extracts on biofilm formation by oral streptococci and the potential mechanisms behind the effects.

DESIGN: We examined the effects of five types of tea extracts (green, oolong, black, pu-erh and chrysanthemum tea) on cell surface hydrophobicity and auto-aggregation of three different streptococcal species (Streptococcus mutans, Streptococcus salivarius and Streptococcus mitis) and evaluated their biofilm formation on four disparate hard surfaces (glass, stainless steel, hydroxyapatite and titanium). The correlation between biofilm formation and the cellular properties were investigated in order to study the mechanisms by which the tea extracts affect biofilm formation.

RESULTS: Results show that the tea extracts reduced cell surface hydrophobicity (by up to 57.9 %) and, in some cases, altered cellular auto-aggregation (by up to 12 %) and biofilm formation (by up to 2.61 log CFU cm[-2]). Specifically, oolong tea extract was found to enhance biofilm formation by increasing cellular auto-aggregation and pu-erh tea extract retarded biofilm formation by increasing auto-aggregation. Biofilm formation correlated well to cell surface hydrophobicity and auto-aggregation in combination, but not to either one alone as determined by multiple linear regression analysis.

CONCLUSIONS: Tea extracts have the ability to modulate streptococcal biofilm formation by altering cell surface hydrophobicity and cellular aggregation.}, } @article {pmid33418325, year = {2021}, author = {Luo, YH and Lai, YS and Zheng, C and Ilhan, ZE and Ontiveros-Valencia, A and Long, X and Krajmalnik-Brown, R and Rittmann, BE}, title = {Increased expression of antibiotic-resistance genes in biofilm communities upon exposure to cetyltrimethylammonium bromide (CTAB) and other stress conditions.}, journal = {The Science of the total environment}, volume = {765}, number = {}, pages = {144264}, doi = {10.1016/j.scitotenv.2020.144264}, pmid = {33418325}, issn = {1879-1026}, mesh = {*Anti-Bacterial Agents/toxicity ; Biofilms ; *COVID-19 ; Cetrimonium ; Drug Resistance, Microbial/genetics ; Humans ; Microbial Sensitivity Tests ; SARS-CoV-2 ; }, abstract = {Quaternary ammonium compounds (QAC, e.g., cetyltrimethylammonium bromide, (CTAB)) are widely used as surfactants and disinfectants. QAC already are commonly found in wastewaters, and their concentration could increase, since QAC are recommended to inactivate the SARS-CoV-2 (COVID-19) virus. Exposure of bacteria to QAC can lead to proliferation of antibiotic resistance genes (ARG). In particular, O2-based membrane biofilm reactors (O2-MBfRs) achieved excellent CTAB biodegradation, but ARG increased in their biofilms. Here, we applied meta-transcriptomic analyses to assess the impacts of CTAB exposure and operating conditions on microbial community's composition and ARG expression in the O2-MBfRs. Two opportunistic pathogens, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, dominated the microbial communities and were associated with the presence of ARG. Operating conditions that imposed stress on the biofilms, i.e., limited supplies of O2 and nitrogen or a high loading of CTAB, led to large increases in ARG expression, particularly for genes conferring antibiotic-target protection. Important within the efflux pumps was the Resistance-Nodulation-Division (RND) family, which may have been active in exporting CTAB from cells. Oxidative stress appeared to be the key factor that triggered ARG proliferation by selecting intrinsically resistant species and accentuating the expression of ARG. Our findings suggest that means to mitigate the spread of ARG, such as shown here in a O2-based membrane biofilm reactor, need to consider the impacts of stressors, including QAC exposure and stressful operating conditions.}, } @article {pmid33417975, year = {2021}, author = {Ling, N and Wang, X and Liu, D and Shen, Y and Zhang, D and Ou, D and Fan, H and Wang, J and Ding, Y and Zhang, J and Wu, Q and Ye, Y}, title = {Role of fliC on biofilm formation, adhesion, and cell motility in Cronobacter malonaticus and regulation of luxS.}, journal = {Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association}, volume = {149}, number = {}, pages = {111940}, doi = {10.1016/j.fct.2020.111940}, pmid = {33417975}, issn = {1873-6351}, mesh = {Bacterial Adhesion/*physiology ; Bacterial Proteins/genetics/metabolism ; Cronobacter/*physiology ; Flagellin/*metabolism ; Gene Deletion ; Gene Expression Regulation, Bacterial/physiology ; Movement ; }, abstract = {Cronobacter malonaticus is one of the important foodborne pathogens causing infections mainly in adults. Biofilm formation, adhesion, and motility in Cronobacter have been documented, but the implying molecular mechanism has received little attention. Here, a comparison in biofilm formation, adhesion ability, and cell motility among wild type (WT), △luxS, and △fliC strains were analyzed using scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM). The thickest biofilm was formed by WT, followed by △luxS and △fliC. Furthermore, the deletion of fliC caused the loss of cell motility and the failure to flagella biosynthesis and mature biofilm formation. Besides, the adhesion abilities of △luxS and △fliC to biotic cells (LoVo and IEC-6) and abiotic surface (glass) were significantly decreased compared to WT, revealing that fliC might have an important role in the organism's invasion properties. We further demonstrated that the expression of negative regulator (flgM) of flagellin in △luxS was higher than that in WT, which indicated that luxS indirectly contributed to fliC expression. Our findings provided a novel perspective for precaution and control of C. malonaticus through intercepting fliC-mediated adhesion to biotic cells and abiotic surface.}, } @article {pmid33415933, year = {2020}, author = {Hosseinpour Nader, A and Sodagar, A and Akhavan, A and Pourhajibagher, M and Bahador, A}, title = {Antibacterial Effects of Orthodontic Primer Harboring Chitosan Nanoparticles against the Multispecies Biofilm of Cariogenic Bacteria in a Rat Model.}, journal = {Folia medica}, volume = {62}, number = {4}, pages = {817-824}, doi = {10.3897/folmed.62.e50200}, pmid = {33415933}, issn = {1314-2143}, mesh = {Animals ; Bacteria/drug effects/*growth & development ; Bacterial Infections/*drug therapy/microbiology ; *Biofilms ; Chitosan/*administration & dosage ; Disease Models, Animal ; Nanoparticles/*administration & dosage ; Orthodontic Brackets/*microbiology ; Rats ; Rats, Wistar ; Saliva/*microbiology ; }, abstract = {INTRODUCTION: Microbial biofilm accumulation around orthodontic brackets and composite is a common complication of fixed orth-odontic treatment. This study assessed the antibacterial effects of orthodontic primer containing chitosan nanoparticles (CNPs) against the multispecies biofilm of cariogenic bacteria in а rat model.

MATERIALS AND METHODS: Transbond XT orthodontic primer containing 0%, 1%, 5%, and 10% CNPs was experimentally prepared. The Wistar rats were randomly divided into four groups (n=7) of control (0% CNPs), 1%, 5% and 10% CNPs. The oral cavities of the rats were infected with cariogenic bacteria. After anesthetizing the rats, 1 drop (10 µL) of primer with different concentrations of CNPs was applied to their central incisor and light-cured for 20 seconds. Transbond XT orthodontic adhesive (2 × 2 mm) was applied on the primer. Another drop (10 µL) of primer was applied and light-cured for 40 seconds. The number of Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus colonies in the saliva of rats was quantified at 24 hours, 4 days and 7 days.

RESULTS: Adding 1% (p=0.005), 5% (p<0.001) and 10% (p<0.001) of CNPs to orthodontic primer significantly reduced the S. mutans colony count at 24 hours compared with the control group. At 24 hours, the mean S. sanguinis colony counts in the 5% (p=0.04) and 10% (p=0.02) CNP groups were significantly lower than that in the control group. Also, at 4 and 7 days, the mean colony counts in the 5% and 10% CNP groups were significantly lower than that in the control group (p<0.05). At 24 hours and 4 days, the mean L. acidophilus colony count in the 10% CNP group was significantly lower than that in the control group (p<0.05). At 7 days, rats with failed adhesive showed a significantly higher count of all three bacteria compared with rats with adhesive (p<0.05).

CONCLUSIONS: The addition of 5% CNPs to orthodontic primer significantly decreased the colony count of cariogenic bacteria in rats.}, } @article {pmid33415727, year = {2021}, author = {Pavissich, JP and Li, M and Nerenberg, R}, title = {Spatial distribution of mechanical properties in Pseudomonas aeruginosa biofilms, and their potential impacts on biofilm deformation.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {4}, pages = {1564-1575}, doi = {10.1002/bit.27671}, pmid = {33415727}, issn = {1097-0290}, mesh = {*Biofilms ; Pseudomonas aeruginosa/*physiology ; *Stress, Mechanical ; }, abstract = {The mechanical properties of biofilms can be used to predict biofilm deformation under external forces, for example, under fluid flow. We used magnetic tweezers to spatially map the compliance of Pseudomonas aeruginosa biofilms at the microscale, then applied modeling to assess its effects on biofilm deformation. Biofilms were grown in capillary flow cells with Reynolds numbers (Re) ranging from 0.28 to 13.9, bulk dissolved oxygen (DO) concentrations from 1 mg/L to 8 mg/L, and bulk calcium ion (Ca[2+]) concentrations of 0 and 100 mg CaCl2 /L. Higher Re numbers resulted in more uniform biofilm morphologies. The biofilm was stiffer at the center of the flow cell than near the walls. Lower bulk DO led to more stratified biofilms. Higher Ca[2+] concentrations led to increased stiffness and more uniform mechanical properties. Using the experimental mechanical properties, fluid-structure interaction models predicted up to 64% greater deformation for heterogeneous biofilms, compared with a homogeneous biofilms with the same average properties. However, the deviation depended on the biofilm morphology and flow regime. Our results show significant spatial mechanical variability exists at the microscale, and that this variability can potentially affect biofilm deformation. The average biofilm mechanical properties, provided in many studies, should be used with caution when predicting biofilm deformation.}, } @article {pmid33415496, year = {2021}, author = {Gaebler, HJ and Hughes, JM and Eberl, HJ}, title = {Thermodynamic Inhibition in a Biofilm Reactor with Suspended Bacteria.}, journal = {Bulletin of mathematical biology}, volume = {83}, number = {2}, pages = {10}, pmid = {33415496}, issn = {1522-9602}, mesh = {Bacteria/growth & development ; *Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors ; *Models, Biological ; *Thermodynamics ; }, abstract = {We formulate a biofilm reactor model with suspended bacteria that accounts for thermodynamic growth inhibition. The reactor model is a chemostat style model consisting of a single replenished growth promoting substrate, a single reaction product, suspended bacteria, and wall attached bacteria in the form of a bacterial biofilm. We present stability conditions for the washout equilibrium using standard techniques, demonstrating that analytical results are attainable even with the added complexity from thermodynamic inhibition. Furthermore, we numerically investigate the longterm behaviour. In the computational study, we investigate model behaviour for select parameters and two commonly used detachment functions. We investigate the effects of thermodynamic inhibition on the model and find that thermodynamic inhibition limits substrate utilization/production both inside the biofilm and inside the aqueous phase, resulting in less suspended bacteria and a thinner biofilm.}, } @article {pmid33412499, year = {2021}, author = {Ohore, OE and Zhang, S and Guo, S and Addo, FG and Manirakiza, B and Zhang, W}, title = {Ciprofloxacin increased abundance of antibiotic resistance genes and shaped microbial community in epiphytic biofilm on Vallisneria spiralis in mesocosmic wetland.}, journal = {Bioresource technology}, volume = {323}, number = {}, pages = {124574}, doi = {10.1016/j.biortech.2020.124574}, pmid = {33412499}, issn = {1873-2976}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Ciprofloxacin/pharmacology ; Drug Resistance, Microbial/genetics ; Genes, Bacterial ; *Microbiota ; Wetlands ; }, abstract = {This study investigated the fate of ciprofloxacin (CIP) in wetlands dominated by Vallisneria spiralis. About 99% of CIP was degraded from overlaying water within 4 days of treatment but significantly inhibited the nutrient removal capacity (TN, TP, and COD) by causing a drastic reduction in microbial aggregation in epiphytic biofilm and bacterial biodiversity. CIP triggered resistance mechanisms among dominant bacteria phyla such as Proteobacteria, Actinobacteria, and Planctomycetes causing their increased relative abundance. Additionally, the relative abundances of eukaryotic microorganisms (including; Chloroplastida, Metazoa, and Rhizaria) and 13 ARGs subtypes (including; Efflux pump, Tetracycline, Multi-drug, Rifampin, Beta-lactam, Peptide, Trimethoprim) were significantly increased. While dominant metabolic pathways such as Carbohydrate, amino acid, energy and nucleotide metabolism were inhibited. This study revealed that V. spiralis has great sorption capacity for CIP than sediment and though CIP was effectively removed from the overlying water, it caused a prolonged effect on the epiphytic biofilm microbial communities.}, } @article {pmid33412274, year = {2021}, author = {Martínez-García, S and Peralta, H and Betanzos-Cabrera, G and Chavez-Galan, L and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {Proteomic comparison of biofilm vs. planktonic Staphylococcus epidermidis cells suggests key metabolic differences between these conditions.}, journal = {Research in microbiology}, volume = {172}, number = {2}, pages = {103796}, doi = {10.1016/j.resmic.2020.103796}, pmid = {33412274}, issn = {1769-7123}, mesh = {Bacterial Proteins/*genetics/*metabolism ; *Biofilms ; Carbohydrate Metabolism ; Chromatography, Liquid ; Citric Acid Cycle ; DNA, Bacterial ; Gene Expression Regulation, Bacterial ; Glycolysis ; Humans ; *Proteome ; Proteomics ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*genetics/*metabolism ; Tandem Mass Spectrometry ; }, abstract = {Previous studies have shown that biofilm-forming bacteria are deficient in tricarboxylic acid (TCA) cycle metabolites, suggesting a relationship between these cellular processes. In this work, we compared the proteomes of planktonic vs biofilm cells from a clinical strain of Staphylococcus epidermidis using LC-MS/MS. A total of 168 proteins were identified from both growth conditions. The biofilm cells showed enrichment of proteins participating in glycolysis for the formation of pyruvate; however, the absence of TCA cycle proteins and the presence of lactate dehydrogenase, formate acetyltransferase, and acetoin reductase suggested that pyruvate was catabolized to their respective products: lactate, formate and acetoin. On the other hand, planktonic cells showed proteins participating in glycolysis and the TCA cycle, the pentose phosphate pathway, gluconeogenesis, ATP generation and the oxidative stress response. Functional networks with higher interconnection were predicted for planktonic proteins. We propose that in S. epidermidis, the relative absence of TCA cycle proteins is associated with the formation of biofilms and that lactate, formate and acetoin are the end products of partial glucose metabolism.}, } @article {pmid33411249, year = {2021}, author = {Chakraborty, P and Paul, P and Kumari, M and Bhattacharjee, S and Singh, M and Maiti, D and Dastidar, DG and Akhter, Y and Kundu, T and Das, A and Tribedi, P}, title = {Attenuation of Pseudomonas aeruginosa biofilm by thymoquinone: an individual and combinatorial study with tetrazine-capped silver nanoparticles and tryptophan.}, journal = {Folia microbiologica}, volume = {66}, number = {2}, pages = {255-271}, pmid = {33411249}, issn = {1874-9356}, mesh = {Anti-Bacterial Agents/pharmacology ; Benzoquinones ; Biofilms ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; *Pseudomonas aeruginosa ; Silver/pharmacology ; Tryptophan ; }, abstract = {Microbial biofilm indicates a cluster of microorganisms having the capability to display drug resistance property, thereby increasing its proficiency in spreading diseases. In the present study, the antibiofilm potential of thymoquinone, a black seed-producing natural molecule, was contemplated against the biofilm formation by Pseudomonas aeruginosa. Substantial antimicrobial activity was exhibited by thymoquinone against the test organism wherein the minimum inhibitory concentration of the compound was found to be 20 μg/mL. Thereafter, an array of experiments (crystal violet staining, protein count, and microscopic observation, etc.) were carried out by considering the sub-MIC doses of thymoquinone (5 and 10 μg/mL), each of which confirmed the biofilm attenuating capacity of thymoquinone. However, these concentrations did not show any antimicrobial activity. Further explorations on understanding the underlying mechanism of the same revealed that thymoquinone accumulated reactive oxygen species (ROS) and also inhibited the expression of the quorum sensing gene (lasI) in Pseudomonas aeruginosa. Furthermore, by taking up a combinatorial approach with two other reported antibiofilm agents (tetrazine-capped silver nanoparticles and tryptophan), the antibiofilm efficiency of thymoquinone was expanded. In this regard, the highest antibiofilm activity was observed when thymoquinone, tryptophan, and tetrazine-capped silver nanoparticles were applied together against Pseudomonas aeruginosa. These combinatorial applications of antibiofilm molecules were found to accumulate ROS in cells that resulted in the inhibition of biofilm formation. Thus, the combinatorial study of these antibiofilm molecules could be applied to control biofilm threats as the tested antibiofilm molecules alone or in combinations showed negligible or very little cytotoxicity.}, } @article {pmid33407117, year = {2021}, author = {Barger, PC and Liles, MR and Beck, BH and Newton, JC}, title = {Differential production and secretion of potentially toxigenic extracellular proteins from hypervirulent Aeromonas hydrophila under biofilm and planktonic culture.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {8}, pmid = {33407117}, issn = {1471-2180}, support = {101701-139711-2052//College of Veterinary Medicine, Auburn University/ ; 101702-139711-2052//College of Veterinary Medicine, Auburn University/ ; }, mesh = {Aeromonas hydrophila/genetics/*growth & development/metabolism/*pathogenicity ; Alabama ; Animals ; Aquaculture ; Bacterial Proteins/genetics/*metabolism/pharmacology ; Bacteriological Techniques ; Biofilms/*growth & development ; Chromatography, High Pressure Liquid ; Fish Diseases/microbiology ; Gram-Negative Bacterial Infections/microbiology/*veterinary ; Ictaluridae/*microbiology ; Plankton ; Proteomics ; Tandem Mass Spectrometry ; Virulence ; Whole Genome Sequencing ; }, abstract = {BACKGROUND: Hypervirulent Aeromonas hydrophila (vAh) is an emerging pathogen in freshwater aquaculture that results in the loss of over 3 million pounds of marketable channel catfish, Ictalurus punctatus, and channel catfish hybrids (I. punctatus, ♀ x blue catfish, I. furcatus, ♂) each year from freshwater catfish production systems in Alabama, U.S.A. vAh isolates are clonal in nature and are genetically unique from, and significantly more virulent than, traditional A. hydrophila isolates from fish. Even with the increased virulence, natural infections cannot be reproduced in aquaria challenges making it difficult to determine modes of infection and the pathophysiology behind the devastating mortalities that are commonly observed. Despite the intimate connection between environmental adaptation and plastic response, the role of environmental adaption on vAh pathogenicity and virulence has not been previously explored. In this study, secreted proteins of vAh cultured as free-living planktonic cells and within a biofilm were compared to elucidate the role of biofilm growth on virulence.

RESULTS: Functional proteolytic assays found significantly increased degradative activity in biofilm secretomes; in contrast, planktonic secretomes had significantly increased hemolytic activity, suggesting higher toxigenic potential. Intramuscular injection challenges in a channel catfish model showed that in vitro degradative activity translated into in vivo tissue destruction. Identification of secreted proteins by HPLC-MS/MS revealed the presence of many putative virulence proteins under both growth conditions. Biofilm grown vAh produced higher levels of proteolytic enzymes and adhesins, whereas planktonically grown cells secreted higher levels of toxins, porins, and fimbrial proteins.

CONCLUSIONS: This study is the first comparison of the secreted proteomes of vAh when grown in two distinct ecological niches. These data on the adaptive physiological response of vAh based on growth condition increase our understanding of how environmental niche partitioning could affect vAh pathogenicity and virulence. Increased secretion of colonization factors and degradative enzymes during biofilm growth and residency may increase bacterial attachment and host invasiveness, while increased secretion of hemolysins, porins, and other potential toxins under planktonic growth (or after host invasion) could result in increased host mortality. The results of this research underscore the need to use culture methods that more closely mimic natural ecological habitat growth to improve our understanding of vAh pathogenesis.}, } @article {pmid33406640, year = {2021}, author = {Seyler, TM and Moore, C and Kim, H and Ramachandran, S and Agris, PF}, title = {A New Promising Anti-Infective Agent Inhibits Biofilm Growth by Targeting Simultaneously a Conserved RNA Function That Controls Multiple Genes.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33406640}, issn = {2079-6382}, support = {CHE-1929741//National Science Foundation/ ; }, abstract = {Combating single and multi-drug-resistant infections in the form of biofilms is an immediate challenge. The challenge is to discover innovative targets and develop novel chemistries that combat biofilms and drug-resistant organisms, and thwart emergence of future resistant strains. An ideal novel target would control multiple genes, and can be inhibited by a single compound. We previously demonstrated success against Staphylococcus aureus biofilms by targeting the tRNA-dependent regulated T-box genes, not present in the human host. Present in Gram-positive bacteria, T-box genes attenuate transcription with a riboswitch-like element that regulates the expression of aminoacyl-tRNA synthetases and amino acid metabolism genes required for cell viability. PKZ18, the parent of a family of compounds selected in silico from 305,000 molecules, inhibits the function of the conserved T-box regulatory element and thus blocks growth of antibiotic-resistant S. aureus in biofilms. The PKZ18 analog PKZ18-22 was 10-fold more potent than vancomycin in inhibiting growth of S. aureus in biofilms. In addition, PKZ18-22 has a synergistic effect with existing antibiotics, e.g., gentamicin and rifampin. PKZ18-22 inhibits the T-box regulatory mechanism, halts the transcription of vital genes, and results in cell death. These effects are independent of the growth state, planktonic or biofilm, of the bacteria, and could inhibit emergent strains.}, } @article {pmid33403919, year = {2022}, author = {Nain, Z and Mansur, FJ and Syed, SB and Islam, MA and Azakami, H and Islam, MR and Karim, MM}, title = {Inhibition of biofilm formation, quorum sensing and other virulence factors in Pseudomonas aeruginosa by polyphenols of Gynura procumbens leaves.}, journal = {Journal of biomolecular structure & dynamics}, volume = {40}, number = {12}, pages = {5357-5371}, doi = {10.1080/07391102.2020.1870563}, pmid = {33403919}, issn = {1538-0254}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins/metabolism ; Biofilms ; Plant Extracts/chemistry/pharmacology ; Polyphenols/pharmacology ; *Pseudomonas aeruginosa/metabolism ; Quercetin/pharmacology ; *Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Quorum sensing (QS) enables virulence factors in bacteria for biofilm formation and pathogenic invasion. Therefore, quorum quenching (QQ), disruption of QS circuit, becomes an alternative antimicrobial therapy. In this study, leaf extract of Gynura procumbens (GP) was used to inhibit biofilm and virulent factors in Pseudomonas aeruginosa. The extract inhibited the biofilm production (p ≤ 0.05) in P. aeruginosa strains MZ2F and MZ4A. The minimum biofilm eradication concentration (MBEC) was recorded at 250 and 500 μg/ml while total activity was found at 288 and 144 ml/g, respectively. Moreover, a significant reduction of virulence factors (p ≤ 0.05) at sub-MBEC without affecting the growth implies the QQ action of the extract. The bioactive fractions were rich in polyphenols and tentatively identified as quercetin and myricetin (Rf=0.53-0.60). Furthermore, we employed computational methods to validate our findings and their interactions with QS receptors (LasR and RhlR). Interestingly, docking studies have also shown that quercetin and myricetin are the promising anti-QS agents out of 31 GP compounds. Notably, their binding affinity ranged between -9.77 and -10.52 kcal/mol for both QS receptors, with controls ranging from -5.40 to -8.97 kcal/mol. Besides, ΔG of quercetin and myricetin with LasR was -71.56 and -74.88 kcal/mol, respectively. Moreover, compounds were suitable drug candidates with stable binding interactions. Therefore, the anti-QS activity of GP leaves and the identified polyphenols can be used in developing QQ-based therapeutics. Communicated by Ramaswamy H. Sarma.}, } @article {pmid33403849, year = {2021}, author = {Zeng, W and Huang, Y and Xia, A and Liao, Q and Chen, K and Zhu, X and Zhu, X}, title = {Thermoresponsive Surfaces Grafted by Shrinkable Hydrogel Poly(N-isopropylacrylamide) for Controlling Microalgae Cells Adhesion during Biofilm Cultivation.}, journal = {Environmental science & technology}, volume = {55}, number = {2}, pages = {1178-1189}, doi = {10.1021/acs.est.0c03084}, pmid = {33403849}, issn = {1520-5851}, mesh = {Acrylamides ; Acrylic Resins ; Biofilms ; Cell Adhesion ; *Chlorella vulgaris ; Hydrogels ; *Microalgae ; Surface Properties ; Temperature ; }, abstract = {Microalgae is a promising candidate for reducing greenhouse gas and producing renewable biofuels. For microalgae biofilm cultivation, a strong adhesion ability of microalgae cells onto the surface is a prerequisite to resist the fluid shear stress, while strong adhesion is not of benefit to the biofilm harvesting process. To solve this dilemma, a thermoresponsive surface (TMRS) with lower critical solution temperature of 33 °C was made by grafting N-isopropylacrylamide onto a silicate glass slide. The wettability of the TMRS changed from hydrophilic (contact angle of 59.4°) to hydrophobic (contact angle of 91.6°) when the temperature rose from 15 to 35 °C, resulting in the increase of adhesion energy of the TMRS to Chlorella vulgaris cells by 135.6%. The experiments showed that the cells were more likely to attach onto the TMRS at the higher temperature of 35 °C owing to the surface microstructures generated by the hydrogel layer shrinkage, which is similar in size to the microalgae cells. And the cell coverage rate on TMRS increased by 32% compared to the original glass surface. Conversely, the cells separate easily from the TMRS at a lower temperature of 15 °C, and the cell adhesion density was reduced by 19% due to hydrogel layer swelling to a relatively flat surface.}, } @article {pmid33403293, year = {2020}, author = {Ren, P and Chen, T and Liu, N and Sun, W and Hu, G and Yu, Y and Yu, B and Ouyang, P and Liu, D and Chen, Y}, title = {Efficient Biofilm-Based Fermentation Strategies by eDNA Formation for l-Proline Production with Corynebacterium glutamicum.}, journal = {ACS omega}, volume = {5}, number = {51}, pages = {33314-33322}, pmid = {33403293}, issn = {2470-1343}, abstract = {Biofilms could provide favorable conditions for the growth of cells during industrial fermentation. However, biofilm-immobilized fermentation has not yet been reported in Corynebacterium glutamicum (C. glutamicum), one of the main strains for amino acid production. This is mainly because C. glutamicum has a poor capability of adsorption onto materials or forming an extracellular polymeric substance (EPS). Here, an engineered strain, C. glutamicum Pro-ΔexeM, was created by removing the extracellular nuclease gene exeM, which effectively increased extracellular DNA (eDNA) in the EPS and cell adhesiveness onto carrier materials. In repeated-batch fermentation using the biofilm, l-proline production increased from 10.2 to 17.1 g/L. In summary, this research demonstrated that a synthetic C. glutamicum biofilm could be favorable for l-proline production, which could be extended to other industrial applications of C. glutamicum, and the strategy may also be applicable to the engineering of other strains.}, } @article {pmid33402912, year = {2020}, author = {Kadry, AA and Al-Kashef, NM and El-Ganiny, AM}, title = {Distribution of genes encoding adhesins and biofilm formation capacity among Uropathogenic Escherichia coli isolates in relation to the antimicrobial resistance.}, journal = {African health sciences}, volume = {20}, number = {1}, pages = {238-247}, pmid = {33402912}, issn = {1729-0503}, mesh = {Adhesins, Escherichia coli/*genetics ; Adult ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Drug Resistance, Bacterial/drug effects/*genetics ; Escherichia coli Infections/drug therapy ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Polymerase Chain Reaction ; Urinary Tract Infections/drug therapy/microbiology ; Uropathogenic Escherichia coli/drug effects/*genetics/*isolation & purification/pathogenicity ; Virulence/drug effects ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Escherichia coli is the most predominant pathogen involved in UTIs. Mainly, fimbrial surface appendages are implicated in adherence to urothelium besides non-fimbrial proteins.

OBJECTIVES: to determine prevalence of genes encoding fimbrial and non-fimbrial proteins among Uropathogenic Escherichia coli (UPEC). Furthermore, distribution of these genes and biofilm formation capacity were investigated in relation to antimicrobial resistance.

METHODS: Antimicrobial susceptibility of 112 UPEC isolates was performed using disc diffusion method. ESBL production was confirmed by double disc synergy test. Genes encoding fimbrial and non-fimbrial proteins were detected using PCR and biofilm formation was investigated using microtitre plate assay.

RESULTS: UPEC isolates exhibited high resistance against doxycyclines (88.39 %), β-lactams (7.14-86.6%), sulphamethoxazole-trimethoprim (53.75%) and fluoro-quinolones (50%). Fifty percent of tested isolates were ESBL producers. PapGII gene was statistically more prevalent among pyelonephritis isolates. SfaS, focG and picU genes were statistically associated with fluoroquinolone (FQs) sensitive isolates and Dr/afaBC gene was statistically associated with ESBL production. Moreover, non-MDR isolates produced sturdier biofilm.

CONCLUSION: PapGII adhesin variant seems to have a critical role in colonization of upper urinary tract. There is a possible link between antimicrobial resistance and virulence being capable of affecting the distribution of some genes besides its negative impact on biofilm formation.}, } @article {pmid33402616, year = {2020}, author = {Sadan, H and Shanthala, BM and Zareena, MA and Babu, G and Vijayan, V}, title = {In vitro evaluation of milk-based, soy-based, and amino acid-based infant formulas on Streptococcus mutans biofilm formation.}, journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry}, volume = {38}, number = {4}, pages = {350-354}, doi = {10.4103/JISPPD.JISPPD_241_20}, pmid = {33402616}, issn = {1998-3905}, mesh = {Amino Acids ; Animals ; Biofilms ; Humans ; Infant Formula ; Milk ; *Soy Milk ; *Streptococcus mutans ; }, abstract = {BACKGROUND AND OBJECTIVE: Infant formulas are based on milk, and the addition of simple carbohydrates as a caloric source, for infants. The carbohydrates added in infant formulas can cause a significant increase of Streptococcus mutans in the oral cavity of infants adding to their cariogenicity.

AIM: The aim of the study was to assess and compare the biofilm formation in three commercially available infant formulas;which are based on milk, soy and amino acid.

SETTINGS AND DESIGN: In vitro microbiological assay of Streptococcus mutans biofilm formation in milk based, soy based and amino acid based infant formulas.

MATERIALS AND METHODS: Twenty-four hour-cultured S. mutans and microtiter plates were used for analysis. At microtiter plate, 190 μL of modified TSB broth containing SBF, MBF, amino acid-based infant formulas, and dairy whitener as a positive control in five dilutions (1:05, 1:10, 1:20, 1:40, and 1:80) was added into respective wells. 10 μL of cultured S. mutans was inoculated into the wells and incubated at 37°C for 24 h. Biofilm was washed, fixed, and stained with crystal violet. The absorbance was measured to evaluate biofilm growth, which was read as optical densities in a spectrophotometer at 490 nm and was tabulated.

RESULTS: Three infant formulas tested showed S. mutans biofilm growth. Minimal biofilm growth was observed in amino acid-based formula at 1:80 dilution, followed by MBF at 1:10 dilution and SBF at 1:80 dilution.

CONCLUSION: Commercially available infant formulas favor S. mutans biofilm growth and can be cariogenic. Amino acid-based infant formula was found to have less S. mutans biofilm growth than MBF and SBF.}, } @article {pmid33401970, year = {2020}, author = {Signori, C and Maske, TT and Digmayer Romero, VH and Cenci, MS}, title = {Influence of biofilm removal from the tooth-restoration interface on the progression of secondary caries lesions: a preliminary in vitro model study.}, journal = {Biofouling}, volume = {36}, number = {10}, pages = {1272-1283}, doi = {10.1080/08927014.2020.1870219}, pmid = {33401970}, issn = {1029-2454}, mesh = {*Biofilms ; Dental Caries/therapy ; Dental Caries Susceptibility ; Dentin ; Humans ; Lactobacillus ; Saliva ; Tooth Demineralization ; }, abstract = {This study investigated the effects of biofilm removal from the tooth-restoration surface on secondary caries lesion progression. Biofilms were grown for up to 28 days on resin-restored enamel-dentin disks with an interfacial gap with DMM or DMM + 1% sucrose under five different protocols of Visible Biofilm Removal (V-BR; n = 7): (1) without V-BR, (2) with partial V-BR, (3) with total V-BR, (4) with total V-BR and saliva reinoculation, and (5) without V-BR under 9 h of cariogenic challenge. V-BR was performed at 7, 14 and 21 days. ΔS and CFU counts served as outcome variables. Linear regression models showed that ΔS values were higher for outer lesions than wall lesions, and outer lesion progression generally increased over time (p < 0.01). All protocols tested, except total V-BR, increased the lactobacilli count (p < 0.005). V-BR did not influence the progression of caries lesions on the cavity wall in this biofilm model.}, } @article {pmid33401545, year = {2021}, author = {Kwon, JS and Kim, JY and Mangal, U and Seo, JY and Lee, MJ and Jin, J and Yu, JH and Choi, SH}, title = {Durable Oral Biofilm Resistance of 3D-Printed Dental Base Polymers Containing Zwitterionic Materials.}, journal = {International journal of molecular sciences}, volume = {22}, number = {1}, pages = {}, pmid = {33401545}, issn = {1422-0067}, support = {202011D04//Korea Medical Device Development Fund/ ; }, mesh = {Bacterial Adhesion ; Biocompatible Materials/*pharmacology ; Biofilms/*drug effects/growth & development ; Composite Resins/*chemistry ; Dental Materials/*pharmacology ; Humans ; Materials Testing ; Methacrylates/chemistry ; Mouth/*drug effects/microbiology ; Phosphorylcholine/analogs & derivatives/chemistry ; Polymers/*chemistry ; Printing, Three-Dimensional/*instrumentation ; Streptococcus mutans/drug effects/metabolism ; }, abstract = {Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.}, } @article {pmid33401413, year = {2021}, author = {Abruzzo, A and Giordani, B and Parolin, C and De Gregorio, PR and Foschi, C and Cerchiara, T and Bigucci, F and Vitali, B and Luppi, B}, title = {Lactobacillus crispatus BC1 Biosurfactant Delivered by Hyalurosomes: An Advanced Strategy to Counteract Candida Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {33401413}, issn = {2079-6382}, abstract = {The emergence of resistance to antifungal drugs has made the treatment of vulvovaginal candidiasis (VVC) very challenging. Among natural substances, biosurfactants (BS) produced by Lactobacillus have gained increasing interest in counteracting Candida infections for their proven anti-adhesive properties and safety profile. In the present study, liposomes (LP-BS) or liposomes coated with hyaluronic acid (HY-LP-BS) were prepared in the presence of the BS isolated from the vaginal strain Lactobacillus crispatus BC1 and characterized in terms of size, ζ potential, stability and mucoadhesion. The anti-biofilm activity of free BS, LP-BS and HY-LP-BS was investigated against different Candida albicans and non-albicans strains (C. glabrata, C. lusitaniae, C. tropicalis, C. krusei and C. parapsilosis), clinically isolated from patients affected by VVC. The inhibition of biofilm formation and the dispersal of pre-formed biofilm were evaluated. The obtained phospholipid vesicles showed suitable size for vaginal application and good stability over the storage period. HY-LP-BS exhibited good mucoadhesive properties and the best anti-biofilm profile, both in preventing or limiting the surface colonization by a broad spectrum of Candida species. In conclusion, the formulation of a novel antifungal agent derived from the vaginal microbiota into mucoadhesive nanocarriers appears to be a promising biotherapeutic strategy to counteract vulvovaginal candidiasis.}, } @article {pmid33401282, year = {2021}, author = {Loose, M and Naber, KG and Purcell, L and Wirth, MP and Wagenlehner, FME}, title = {Anti-Biofilm Effect of Octenidine and Polyhexanide on Uropathogenic Biofilm-Producing Bacteria.}, journal = {Urologia internationalis}, volume = {105}, number = {3-4}, pages = {278-284}, pmid = {33401282}, issn = {1423-0399}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biguanides/*pharmacology ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Escherichia coli/*drug effects/*physiology ; Imines ; Microbial Sensitivity Tests ; Proteus mirabilis/*drug effects/*physiology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Pyridines/*pharmacology ; Urinary Catheters/*microbiology ; Urinary Tract Infections/microbiology ; }, abstract = {BACKGROUND: A catheter allowing a release of antibacterial substances such as antiseptics into the bladder could be a new way of preventing biofilm formation and subsequent catheter-associated urinary tract infections.

METHODS: Minimal inhibitory and bactericidal concentration (MIC/MBC) determinations in cation-adjusted Mueller-Hinton broth and artificial urine were performed for 4 antiseptics against 3 uropathogenic biofilm producers, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis. Furthermore, effects of octenidine and polyhexanide against catheter biofilm formation were determined by quantification of biofilm-producing bacteria.

RESULTS: Sodium hypochlorite showed MIC/MBC values between 200 and 800 mg/L for all strains tested. Triclosan was efficient against E. coli and P. mirabilis (MIC ≤2.98 mg/L) but ineffective against P. aeruginosa. Octenidine and polyhexanide showed antibacterial activity against all 3 species tested (MIC 1.95-7.8 and 3.9-31.25 mg/L). Both octenidine and polyhexanide were able to prevent biofilm formation on catheter segments in a concentration dependent manner. Furthermore, adding 250 mg/L of each biocide disrupted biofilms formed by E. coli and P. mirabilis, whereas even 500 mg/L was not sufficient to completely destroy P. aeruginosa biofilms.

CONCLUSION: Octenidine- and polyhexanide-containing antiseptics showed a broad effect against typical uropathogenic biofilm producers even in high dilutions. This study provides a basis for further investigation of the potential of octenidine and polyhexanide as prophylaxis or treatment of catheter biofilms.}, } @article {pmid33401259, year = {2021}, author = {Motealleh, A and Dorri, P and Czieborowski, M and Philipp, B and Kehr, NS}, title = {Bifunctional nanomaterials for simultaneously improving cell adhesion and affecting bacterial biofilm formation on silicon-based surfaces.}, journal = {Biomedical materials (Bristol, England)}, volume = {16}, number = {2}, pages = {025013}, doi = {10.1088/1748-605X/abd872}, pmid = {33401259}, issn = {1748-605X}, mesh = {Bacteria/*metabolism ; Bacterial Adhesion/drug effects ; Biocompatible Materials ; *Biofilms ; Cell Adhesion ; Cell Proliferation ; Dimethylpolysiloxanes/chemistry ; *Drug Delivery Systems ; Fibroblasts/metabolism ; Glass/chemistry ; Humans ; Hydrogen-Ion Concentration ; Luminescence ; Nanocomposites ; Nanostructures/*chemistry ; Nylons/chemistry ; *Printing, Three-Dimensional ; Prostheses and Implants ; Silicon/*chemistry ; Staphylococcus epidermidis/drug effects ; Stress, Mechanical ; Surface Properties ; Time Factors ; }, abstract = {In the biomedical field, silicon-based materials are widely used as implants, biomedical devices, and drug delivery systems. Although these materials show promise for implant technologies and clinical applications, many of them fail to simultaneously possess key properties, such as mechanical stability, biostability, stretchability, cell adhesiveness, biofilm inhibition, and drug delivery ability. Therefore, there is considerable need for the development and improvement of new biomaterials with improved properties. In this context, we describe the synthesis of a new hybrid nanocomposite material that is prepared by incorporating bifunctional nanomaterials onto glass and polydimethylsiloxane surfaces. The results show that our hybrid nanocomposite material is elastic, stretchable, injectable, biostable, has pH-controlled drug delivery ability, and display improved cell adhesion and proliferation and, at the same time, impacted bacterial biofilm formation on the respective surfaces.}, } @article {pmid33401024, year = {2021}, author = {Abuderman, AWA and Muzaheed, }, title = {Antibacterial effectiveness of scaling and root planing with and without photodynamic therapy against Campylobacter rectus counts in the oral biofilm of patients with periodontitis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {33}, number = {}, pages = {102170}, doi = {10.1016/j.pdpdt.2020.102170}, pmid = {33401024}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Campylobacter rectus ; *Chronic Periodontitis/drug therapy ; Dental Scaling ; Female ; Humans ; Male ; *Periodontitis/drug therapy ; *Photochemotherapy/methods ; Photosensitizing Agents/therapeutic use ; Root Planing ; }, abstract = {BACKGROUND: It is hypothesized that scaling and root planning (SRP) with adjunct photodynamic therapy (PDT) is more effective in reducing Campylobacter rectus (C. rectus) from the oral biofilm (OB) among patients with periodontitis, than SRP alone. The objective was to compare the effectiveness of SRP with and without adjunct PDT in reducing OB C. rectus counts of patients with periodontitis.

METHODS: Chronic gastritis patients diagnosed with periodontitis were included. Therapeutically, the patients were divided into 2-groups. Patients in the test- and control-groups underwent SRP with and without adjunct PDT, respectively. In both groups, full-mouth plaque index (PI), bleeding on probing (BOP), probing depth (PD) and marginal bone loss (MBL) were measured and subgingival OB counts of C. rectus were measured at baseline and 12-weeks after treatment. Data normality was assessed and group-comparisons were done using the paired t-test and Man-Whitney U tests. A type-1 error rate of 5 % was used.

RESULTS: Thirty patients with periodontitis were included. All patients had Grade-B/Stage-II periodontitis. All participants were male with no significant difference in age. At baseline PI, BOP, PD and MBL were comparable in both groups. Counts of C. rectus in the subgingival OB samples were similar in both groups at baseline. At 12-weeks of follow-up, PI (P < 0.01), GI (P < 0.01) and PD (P < 0.01) were significantly higher in the control- compared with the test-group compared with baseline. The percentages of C. rectus -positive individuals were higher in the control- than the test-group at 12-weeks' (P < 0.01). At 12-weeks' follow-up the percentages of C. rectus -positive patients were comparable with their respective baseline percentages in the control-group.

CONCLUSION: Compared with SRP alone, adjuvant use of PDT is more efficient in eliminating C. rectus in the OB and reducing clinical parameters in patients with grade-B/Stage-II periodontitis.}, } @article {pmid33399891, year = {2021}, author = {Mohammadi Pelarti, S and Karimi Zarehshuran, L and Babaeekhou, L and Ghane, M}, title = {Antibacterial, anti-biofilm and anti-quorum sensing activities of Artemisia dracunculus essential oil (EO): a study against Salmonella enterica serovar Typhimurium and Staphylococcus aureus.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1529-1537}, pmid = {33399891}, issn = {1432-072X}, mesh = {Animals ; *Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; *Artemisia/chemistry ; *Biofilms/drug effects ; Chlorocebus aethiops ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; *Oils, Volatile/pharmacology ; *Quorum Sensing/drug effects ; *Salmonella typhimurium/drug effects ; *Staphylococcus aureus/drug effects ; Vero Cells ; }, abstract = {The study evaluates the effect of Artemisia dracunculus essential oil (EO) on two pathogenic bacteria Salmonella enterica serovar Typhimurium and Staphylococcus aureus and Vero cell line. To evaluating the anti-biofilm potential of the EO, a microtiter-plate test (MtP) and scanning electron microscopy (SEM) were performed. The quorum-sensing inhibitory properties were examined by QS-related gene expression at sub-MIC concentrations of Artemisia dracunculus EO. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) test was used to determine the cytotoxicity potential of the EO against the Vero cell line and finally, the major components of the EOs were determined using Gas chromatography-mass spectrometry (GC-MS) analysis. The minimum inhibitory concentration (MIC) of the tested EO against S. Typhimurium and S. aureus were 2.5 and 1.25 μl/ml, respectively. In addition, the minimum bactericidal concentration was 5 and 2.5 μl/ml for S. Typhimurium and S. aureus, respectively. Both MtP and SEM showed an acceptable inhibitory and disruption effect of the EO on the biofilm formation at Sub-MIC concentrations. Significant downregulation of luxS, pfs, and hld genes by treatment with MIC/2 concentration of A. dracunculus EO was observed. The IC50 value of A. dracunculus EO against Vero cells was 20 μl/ml. The main detected compound using GC-MS was estragole (methyl chavicol or tarragon) (64.94%). Anti-biofilm, QSI activity, and non-toxicity of A. dracunculus EO reported for the first time in this study propose the use of these plant compounds as alternatives to antibiotics and chemical additives.}, } @article {pmid33398901, year = {2021}, author = {Nosran, A and Kaur, P and Randhawa, V and Chhibber, S and Singh, V and Harjai, K}, title = {Design, synthesis, molecular docking, anti-quorum sensing, and anti-biofilm activity of pyochelin-zingerone conjugate.}, journal = {Drug development research}, volume = {82}, number = {4}, pages = {605-615}, doi = {10.1002/ddr.21781}, pmid = {33398901}, issn = {1098-2299}, mesh = {Anti-Bacterial Agents/*chemical synthesis/*pharmacology ; Biofilms/drug effects ; Drug Design ; Drug Resistance, Bacterial ; Guaiacol/*analogs & derivatives/chemistry/pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Molecular Structure ; Phenols/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Quorum Sensing ; Thiazoles/chemistry/*pharmacology ; }, abstract = {In this article, we report the chemical synthesis of pyochelin-zingerone conjugate via a hydrolysable ester linkage for drug delivery as a "Trojan Horse Strategy." It is a new therapeutic approach to combat microbial infection and to address the issue of multi drug resistance in Gram-negative, nosocomial pathogen Pseudomonas aeruginosa. Pyochelin (Pch) is a catecholate type of phenolate siderophore produced and utilized by the pathogen P. aeruginosa to assimilate iron when colonizing the vertebrate host. Zingerone, is active component present in ginger, a dietary herb known for its anti-virulent approach against P. aeruginosa. In the present study, zingerone was exploited to act as a good substitute for existing antibiotics, known to have developed resistance by most pathogens. Encouraging results were obtained by docking analysis of pyochelin-zingerone conjugate with FptA, the outer membrane receptor of pyochelin. Conjugate also showed anti-quorum sensing activity and also inhibited swimming, swarming, and twitching motilities as well as biofilm formation in vitro.}, } @article {pmid33398400, year = {2021}, author = {Sırıken, B and Öz, V and Erol, İ}, title = {Quorum sensing systems, related virulence factors, and biofilm formation in Pseudomonas aeruginosa isolated from fish.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1519-1528}, pmid = {33398400}, issn = {1432-072X}, support = {PYP.VET.1904.18.001//Ondokuz Mayis Üniversitesi (TR)/ ; }, mesh = {4-Butyrolactone/analogs & derivatives ; Animals ; Bacterial Proteins/genetics ; *Biofilms ; Endopeptidases ; *Fishes/microbiology ; Pseudomonas Infections/microbiology ; *Pseudomonas aeruginosa/genetics/isolation & purification ; Pyocyanine ; *Quorum Sensing/genetics ; *Virulence Factors/genetics ; }, abstract = {In this study, two quorum sensing (QS) system genes, las and rhI; N-3-oxo-dodecanoyl homoserine lactone (AHL; 3-O-C12-HSL); and QS-related virulence factors and correlation between them were assessed in 30 fish origin P. aeruginosa isolates. The detection of two QS system of the isolates, and eight gene regions consisting of four intact (lasI/R, rhlI/R) and four internal (lasI/R, rhlI/R) genes were tested by PCR assay. According to findings, las and rhI QS system genes were detected in 27 and 30 isolates, respectively, while 3-O-C12-HSL was determined in 13 isolates. A total of 22, 27, and 18 isolates were capable of pyocyanin production, protease, and elastase activity, respectively. Biofilm formation was detected using three methods in all 30 isolates: 12 by Congo red agar, 14 by microtiter plate, and 29 by tube test. Twitching and swarming motility types were detected in 30, but the swimming motility was determined in 25 isolates. The rhI QS system genes detected in all of the isolates having three types including motility, PYA production, and protease and elastase activities. The las QS system genes were detected in 27 of the motility, 17 of PYA production, 25 of protease, and 16 of elastase activity having isolates. In conclusion, the high number of P. aeruginosa isolates from fish tested have two QS systems and related virulence factors. There was also correlation between them.}, } @article {pmid33397818, year = {2021}, author = {Akhter, F and Womack, E and Vidal, JE and Le Breton, Y and McIver, KS and Pawar, S and Eichenbaum, Z}, title = {Hemoglobin Induces Early and Robust Biofilm Development in Streptococcus pneumoniae by a Pathway That Involves comC but Not the Cognate comDE Two-Component System.}, journal = {Infection and immunity}, volume = {89}, number = {4}, pages = {}, pmid = {33397818}, issn = {1098-5522}, support = {R21 AI112768/AI/NIAID NIH HHS/United States ; R21 AI144571/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Blood Cells/metabolism ; Hemoglobins/*metabolism ; *Host-Pathogen Interactions ; Humans ; Pneumococcal Infections/blood/metabolism/*microbiology ; Streptococcus pneumoniae/pathogenicity/*physiology ; }, abstract = {Streptococcus pneumoniae grows in biofilms during both asymptomatic colonization and infection. Pneumococcal biofilms on abiotic surfaces exhibit delayed growth and lower biomass and lack the structures seen on epithelial cells or during nasopharyngeal carriage. We show here that adding hemoglobin to the medium activated unusually early and vigorous biofilm growth in multiple S. pneumoniae serotypes grown in batch cultures on abiotic surfaces. Human blood (but not serum, heme, or iron) also stimulated biofilms, and the pore-forming pneumolysin, ply, was required for this induction. S. pneumoniae transitioning from planktonic into sessile growth in the presence of hemoglobin displayed an extensive transcriptome remodeling within 1 and 2 h. Differentially expressed genes included those involved in the metabolism of carbohydrates, nucleotides, amino acid, and lipids. The switch into adherent states also influenced the expression of several regulatory systems, including the comCDE genes. Inactivation of comC resulted in 67% reduction in biofilm formation, while the deletion of comD or comE had limited or no effect, respectively. These observations suggest a novel route for CSP-1 signaling independent of the cognate ComDE two-component system. Biofilm induction and the associated transcriptome remodeling suggest hemoglobin serves as a signal for host colonization in pneumococcus.}, } @article {pmid33397624, year = {2021}, author = {Mouftah, SF and Cobo-Díaz, JF and Álvarez-Ordóñez, A and Mousa, A and Calland, JK and Pascoe, B and Sheppard, SK and Elhadidy, M}, title = {Stress resistance associated with multi-host transmission and enhanced biofilm formation at 42 °C among hyper-aerotolerant generalist Campylobacter jejuni.}, journal = {Food microbiology}, volume = {95}, number = {}, pages = {103706}, doi = {10.1016/j.fm.2020.103706}, pmid = {33397624}, issn = {1095-9998}, mesh = {Animals ; *Biofilms ; Campylobacter Infections/*microbiology/transmission/*veterinary ; Campylobacter jejuni/chemistry/drug effects/genetics/*physiology ; Chickens/microbiology ; Foodborne Diseases/microbiology ; Hot Temperature ; Humans ; Osmotic Pressure ; Peracetic Acid/pharmacology ; Poultry Diseases/*microbiology/transmission ; Stress, Physiological ; }, abstract = {One of the emerging conundrums of Campylobacter food-borne illness is the bacterial ability to survive stressful environmental conditions. We evaluated the heterogeneity among 90 C. jejuni and 21 C. coli isolates from different sources in Egypt with respect to biofilm formation capabilities (under microaerobic and aerobic atmosphere) and resistance to a range of stressors encountered along the food chain (aerobic stress, refrigeration, freeze-thaw, heat, peracetic acid, and osmotic stress). High prevalence (63%) of hyper-aerotolerant (HAT) isolates was observed, exhibiting also a significantly high tolerance to heat, osmotic stress, refrigeration, and freeze-thaw stress, coupled with high biofilm formation ability which was clearly enhanced under aerobic conditions, suggesting a potential link between stress adaptation and biofilm formation. Most HAT multi-stress resistant and strong biofilm producing C. jejuni isolates belonged to host generalist clonal complexes (ST-21, ST-45, ST-48 and ST-206). These findings highlight the potential role of oxidative stress response systems in providing cross-protection (resistance to other multiple stress conditions) and enhancing biofilm formation in Campylobacter and suggest that selective pressures encountered in hostile environments have shaped the epidemiology of C. jejuni in Egypt by selecting the transmission of highly adapted isolates, thus promoting the colonization of multiple host species by important disease-causing lineages.}, } @article {pmid33397610, year = {2021}, author = {Kang, JW and Lee, HY and Kang, DH}, title = {Synergistic bactericidal effect of hot water with citric acid against Escherichia coli O157:H7 biofilm formed on stainless steel.}, journal = {Food microbiology}, volume = {95}, number = {}, pages = {103676}, doi = {10.1016/j.fm.2020.103676}, pmid = {33397610}, issn = {1095-9998}, mesh = {Biofilms/*drug effects ; Citric Acid/*pharmacology ; Disinfectants/chemistry/*pharmacology ; Disinfection/instrumentation/*methods ; Escherichia coli O157/*drug effects/growth & development ; Hot Temperature ; Reactive Oxygen Species/metabolism ; Stainless Steel/analysis ; Water/chemistry/*pharmacology ; }, abstract = {This study investigated the antimicrobial effect of hot water with citric acid against Escherichia coli O157:H7 biofilm on stainless steel (SS). Hot water (50, 60, or 70 °C) with 2% citric acid exhibited a synergistic bactericidal effect on the pathogen biofilm. It was revealed that hot water and citric acid combination induced sub-lethally injured cells. Additionally, mechanisms of the synergistic bactericidal effects of hot water with citric acid were identified through several approaches. In terms of biofilm matrix, hot water removes exopolysaccharides, a major component of extracellular polymeric substances (EPS), thereby increasing contact between surface cells and citric acid, resulting in a synergistic bactericidal effect. In terms of the cell itself, increased permeability of citric acid through cell membranes destructed by hot water promotes the inactivation of superoxide dismutase (SOD) in E. coli O157:H7, which induce synergistic generation of reactive oxygen species (ROS) which promote inactivation of cell by activating lipid peroxidation, resulting in destruction of the cell membrane. Therefore, it is interpreted that when hot water with citric acid is applied to E. coli O157:H7 biofilm, synergy effects on the biofilm matrix and cell itself have a complex interaction with each other, thus causing a dramatic synergistic bactericidal effect.}, } @article {pmid33397288, year = {2021}, author = {Whelan, MVX and Simpson, JC and Ó Cróinín, T}, title = {A novel high-content screening approach for the elucidation of C. jejuni biofilm composition and integrity.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {2}, pmid = {33397288}, issn = {1471-2180}, mesh = {Aerobiosis ; Animals ; Bacterial Adhesion/drug effects ; Campylobacter jejuni/drug effects/*physiology ; Chickens/microbiology ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; High-Throughput Screening Assays ; Molecular Imaging/*methods ; Novobiocin/*pharmacology ; Organic Chemicals/chemistry ; Rhodamines/chemistry ; }, abstract = {BACKGROUND: Campylobacter jejuni is the leading cause of bacterial gastroenteritis worldwide and the main source of infection is contaminated chicken meat. Although this important human pathogen is an obligate microaerophile, it must survive atmospheric oxygen conditions to allow transmission from contaminated chicken meat to humans. It is becoming increasingly evident that formation of biofilm plays a key role in the survival of this organism for extended periods on poultry products. We have recently demonstrated a novel inducible model for the study of adherent C. jejuni biofilm formation under aerobic conditions. By taking advantage of supercoiling mediated gene regulation, incubation of C. jejuni with subinhibitory concentrations of the Gyrase B inhibitor novobiocin was shown to promote the consistent formation of metabolically active adherent biofilm.

RESULTS: In this study, we implement this model in conjunction with the fluorescent markers: TAMRA (live cells) and SytoX (dead cells, eDNA) to develop a novel systematic high-content imaging approach and describe how it can be implemented to gain quantifiable information about the integrity and extracellular polymeric substance (EPS) composition of adherent C. jejuni biofilm in aerobic conditions. We show that this produces a model with a consistent, homogenous biofilm that can be induced and used to screen a range of inhibitors of biofilm adherence and matrix formation.

CONCLUSIONS: This model allows for the first time a high throughput analysis of C. jejuni biofilms which will be invaluable in enabling researchers to develop mechanisms to disrupt these biofilms and reduce the viability of these bacteria under aerobic conditions.}, } @article {pmid33396703, year = {2020}, author = {Jung, T and Hackbarth, M and Horn, H and Gescher, J}, title = {Improving the Cathodic Biofilm Growth Capabilities of Kyrpidia spormannii EA-1 by Undirected Mutagenesis.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33396703}, issn = {2076-2607}, support = {033RC006//Bundesministerium für Bildung und Forschung/ ; }, abstract = {The biotechnological usage of carbon dioxide has become a relevant aim for future processes. Microbial electrosynthesis is a rather new technique to energize biological CO2 fixation with the advantage to establish a continuous process based on a cathodic biofilm that is supplied with renewable electrical energy as electron and energy source. In this study, the recently characterized cathodic biofilm forming microorganism Kyrpidia spormannii strain EA-1 was used in an adaptive laboratory evolution experiment to enhance its cathodic biofilm growth capabilities. At the end of the experiment, the adapted cathodic population exhibited an up to fourfold higher biofilm accumulation rate, as well as faster substratum coverage and a more uniform biofilm morphology compared to the progenitor strain. Genomic variant analysis revealed a genomically heterogeneous population with genetic variations occurring to various extends throughout the community. Via the conducted analysis we identified possible targets for future genetic engineering with the aim to further optimize cathodic growth. Moreover, the results assist in elucidating the underlying processes that enable cathodic biofilm formation.}, } @article {pmid33396528, year = {2020}, author = {Gingichashvili, S and Feuerstein, O and Steinberg, D}, title = {Topography and Expansion Patterns at the Biofilm-Agar Interface in Bacillus subtilis Biofilms.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33396528}, issn = {2076-2607}, abstract = {Bacterial biofilms are complex microbial communities that are formed on various natural and synthetic surfaces. In contrast to bacteria in their planktonic form, biofilms are characterized by their relatively low susceptibility to anti-microbial treatments, in part due to limited diffusion throughout the biofilm and the complex distribution of bacterial cells within. The virulence of biofilms is therefore a combination of the structural properties and patterns of adhesion that anchor them to their host surface. In this paper, we analyze the topographical properties of Bacillus subtilis' biofilm-agar interface across different growth conditions. B. subtilis colonies were grown to maturity on biofilm-promoting agar-based media (LBGM), under standard and stress-inducing growth conditions. The biofilm-agar interface of the colony-type biofilms was modeled using confocal microscopy and computational analysis. Profilometry data were obtained from the macrocolonies and used for the analysis of the surface topography as it relates to the adhesion modes present at the biofilm-agar interface. Fluorescent microspheres were utilized to monitor the expansion patterns present at the interface between the macrocolonies and the solid growth medium. Contact surface analysis revealed topographical changes that could have a direct effect on the adhesion strength of the biofilm to its host surface, thus affecting its potential susceptibility to anti-microbial agents. The topographical characteristics of the biofilm-agar interface partially define the macrocolony structure and may have significant effects on bacterial survival and virulence.}, } @article {pmid33394140, year = {2021}, author = {Cieslinski, J and Ribeiro, VST and Kraft, L and Suss, PH and Rosa, E and Morello, LG and Pillonetto, M and Tuon, FF}, title = {Direct detection of microorganisms in sonicated orthopedic devices after in vitro biofilm production and different processing conditions.}, journal = {European journal of orthopaedic surgery & traumatology : orthopedie traumatologie}, volume = {31}, number = {6}, pages = {1113-1120}, pmid = {33394140}, issn = {1432-1068}, mesh = {*Arthritis, Infectious ; Biofilms ; Humans ; *Prosthesis-Related Infections/diagnosis ; Sonication ; Staphylococcus aureus ; }, abstract = {BACKGROUND: The gold standard for microbial detection in prosthetic joint infections is the multiple culture of the peri-prosthetic tissue. The fluid cultures after sonication can improve the recovery of the microorganisms.

OBJECTIVE: The aim of this study was to evaluate the sonication technique with a plastic bag and the effect of refrigeration on microorganism detection with conventional culturing, MALDI-TOF MS and qPCR assay on an orthopedic screw model.

METHODS: We produced biofilms of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans on orthopedic screws, which were stored under different conditions and temperatures before sonication. After sonication, the mass spectrometry by MALDI-TOF, qPCR and culture protocols was performed using the sonicated fluid, for detecting the microorganisms involved in the biofilm.

RESULTS: The bacterial bioburden decreased by approximately one log after the refrigeration period, in the screws containing P. aeruginosa and S. aureus biofilms. All the microorganisms involved in the screw biofilms were detected with MALDI-TOF and qPCR. Significant reductions in CFU counts occurred only in groups stored in the plastic bag, indicating that changes in temperature and humidity may favor cell death. However, this variation is not important for this model as it did not affect the detection owing to the high counts obtained.

CONCLUSION: Microbial identification by MALDI-TOF in sonicated fluid is feasible. With qPCR, there were no differences between the detection in the screws processed immediately or after refrigeration. It is necessary to consider whether or not the refrigeration period would affect microbial recovery in an explanted prosthesis.}, } @article {pmid33393810, year = {2022}, author = {Liu, D and Huang, Q and Gu, W and Zeng, XA}, title = {A review of bacterial biofilm control by physical strategies.}, journal = {Critical reviews in food science and nutrition}, volume = {62}, number = {13}, pages = {3453-3470}, doi = {10.1080/10408398.2020.1865872}, pmid = {33393810}, issn = {1549-7852}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteria ; *Biofilms ; }, abstract = {Biofilms are multicellular communities of microorganisms held together by a self-produced extracellular matrix, which contribute to hygiene problems in the food and medical fields. Both spoilage and pathogenic bacteria that grow in the complex structure of biofilm are more resistant to harsh environmental conditions and conventional antimicrobial agents. Therefore, it is important to develop eco-friendly preventive methodologies to eliminate biofilms from foods and food contact equipment. The present paper gives an overview of the current physical methods for biofilm control and removal. Current physical strategies adopted for the anti-biofilm treatment mainly focused on use of ultrasound power, electric or magnetic field, plasma, and irradiation. Furthermore, the mechanisms of anti-biofilm action and application of different physical methods are discussed. Physical strategies make it possible to combat biofilm without the use of biocidal agents. The remarkable microbiocidal properties of physical strategies are promising tools for antimicrobial applications.}, } @article {pmid33392626, year = {2021}, author = {Batohi, N and Lone, SA and Marimani, M and Wani, MY and Al-Bogami, AS and Ahmad, A}, title = {Citral and its derivatives inhibit quorum sensing and biofilm formation in Chromobacterium violaceum.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1451-1459}, pmid = {33392626}, issn = {1432-072X}, support = {RDYR180418322304//South African Agency for Science and Technology Advancement/ ; AZMD019//University of the Witwatersrand, Johannesburg/ ; }, mesh = {Acyclic Monoterpenes/chemistry/*pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Chromobacterium/*drug effects/physiology ; Drug Resistance, Multiple, Bacterial/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Quorum Sensing/*drug effects/genetics ; }, abstract = {With an upsurge in multidrug resistant bacteria backed by biofilm defence armours, there is a desperate need of new antibiotics with a non-traditional mechanism of action. Targeting bacteria by misguiding them or halting their communication is a new approach that could offer a new way to combat the multidrug resistance problem. Quorum sensing is considered to be the achilles heel of bacteria that has a lot to offer. Since, both quorum sensing and biofilm formation have been related to drug resistance and pathogenicity, in this study we synthesised new derivatives of citral with antiquorum sensing and biofilm disrupting properties. We previously reported antimicrobial and antiquorum sensing activity of citral and herein we report the synthesis and evaluation of citral and its derivatives (CD1-CD3) for antibacterial, antibiofilm and antiquorum sensing potential against Chromobacterium violaceum using standard methods. Preliminary results revealed that CD1 is the most active of all the derivatives. Qualitative and quantitative evaluation of antiquorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for CD1 followed by CD2, CD3 and citral. These compounds also inhibit biofilm formation at subinhibitory concentrations without causing any bacterial growth inhibition. These results were replicated by RT-qPCR with down regulation of the quorum sensing genes when C. violaceum was treated with these test compounds. Overall, the results are quite encouraging, revealing that biofilm and quorum sensing are interrelated processes and also indicating the potential of these derivatives to impede bacterial communication and biofilm formation.}, } @article {pmid33392614, year = {2021}, author = {Bhatia, E and Sharma, S and Jadhav, K and Banerjee, R}, title = {Combinatorial liposomes of berberine and curcumin inhibit biofilm formation and intracellular methicillin resistant Staphylococcus aureus infections and associated inflammation.}, journal = {Journal of materials chemistry. B}, volume = {9}, number = {3}, pages = {864-875}, doi = {10.1039/d0tb02036b}, pmid = {33392614}, issn = {2050-7518}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Berberine/chemistry/*pharmacology ; Biofilms/*drug effects ; Cells, Cultured ; Curcumin/chemistry/*pharmacology ; Humans ; Inflammation/*drug therapy ; Liposomes/chemical synthesis/chemistry/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Microbial Sensitivity Tests ; Particle Size ; Staphylococcal Infections/*drug therapy ; Surface Properties ; THP-1 Cells ; }, abstract = {The increase in drug-resistant strains of Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has led to an increased rate of infection-related mortality. The emergence of drug resistance has rendered many antibiotics ineffective. The poor penetration and retention of antibiotics in mammalian cells lead to recurrent latent infections. Thus, there is an increasing need for biodegradable, non-toxic anti-infectives that are effective in treating MRSA infections. Phytochemicals such as berberine (BBR) and curcumin (CCR) have long been explored for their antibacterial activities, but their efficacy is often limited due to low bioavailability, water solubility, and poor cell penetration. When used in combination these antimicrobials did not show any synergistic effect against MRSA. Here, both of them were co-encapsulated in liposomes (BCL) and evaluated for biocompatibility, synergistic antimicrobial activity, intracellular infections, associated inflammation, and on biofilms formed by MRSA. Co-encapsulation of BBR and CCR in liposomes decreased their MICs by 87% and 96%, respectively, as compared to their free forms with a FICI of 0.13, indicating synergy between them. BCL inhibited the growth of MRSA and prevented biofilm formation better than free drugs. Co-culture studies showed that intracellular infection was reduced to 77% post BCL treatment. It also reduced the production of pro-inflammatory cytokines by macrophages following infection. The liposomes were found to be five times more efficient than clindamycin and can be used as a potential antimicrobial carrier against intracellular infections.}, } @article {pmid33391216, year = {2020}, author = {Rosales, E and Del Olmo, G and Calero Preciado, C and Douterelo, I}, title = {Phosphate Dosing in Drinking Water Distribution Systems Promotes Changes in Biofilm Structure and Functional Genetic Diversity.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {599091}, pmid = {33391216}, issn = {1664-302X}, abstract = {Water utilities treat drinking water by adding phosphate to prevent metal dissolution from water pipe work systems and particularly lead poisoning. Phosphate can be a limiting nutrient for microbial biofilms in DWDS, yet its effects on these microbial consortia are not well understood. This research presents results from phosphate dosing experiments using a real scale chlorinated DWDS, comparing standard phosphate concentrations of United Kingdom drinking water (1 mgP/L) with a double dose (2 mgP/L) commonly used in plumbosolvency treatment. Biofilm development during phosphate treatment experiments was monitored using a holistic approach by combining metagenomics analysis, flow cytometry and SEM characterisation. The increase of phosphate levels in drinking water, reduced biofilm cell numbers and promoted the presence of poorly distributed biofilms on inner pipe surfaces. Metagenomics analysis using genetic markers (16S rRNA and ITS2) showed that phosphate influenced biofilm community structure, particularly fungal composition. Whole metagenome sequencing showed that phosphate enrichment favoured the presence of sequencing reads associated to ATPases, ion transporters and DNA-interacting proteins, whilst reads associated to nitrogen metabolism were predominant in control samples. This research brings new knowledge regarding the influence of phosphate treatment on the composition and structure of biofilms within DWDS, and the implications that this might have for the management of these systems.}, } @article {pmid33388440, year = {2021}, author = {Subramanian, D and Natarajan, J}, title = {Integrated meta-analysis and machine learning approach identifies acyl-CoA thioesterase with other novel genes responsible for biofilm development in Staphylococcus aureus.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {88}, number = {}, pages = {104702}, doi = {10.1016/j.meegid.2020.104702}, pmid = {33388440}, issn = {1567-7257}, mesh = {Algorithms ; *Biofilms ; Datasets as Topic ; Gene Expression Regulation, Bacterial ; Humans ; Microarray Analysis ; RNA-Seq ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*genetics/*growth & development ; *Supervised Machine Learning ; *Transcriptome ; }, abstract = {Biofilm forming Staphylococcus aureus is a major threat to the health-care industry. It is important to understand the differences between planktonic and biofilm growth forms in the pathogen since conventional treatments targeting the planktonic forms are not effective against biofilms. The current study conducts a meta-analysis of three public transcriptomic profiles to examine the differences in gene expression between the planktonic and biofilm states of S. aureus using random-effects modeling. Mean effect sizes were calculated for 2847 genes among which 726 differentially expressed genes were taken for further analysis. Major genes that are discriminatory between the two conditions were mined using supervised learning techniques and validated by high-accuracy classifiers. Ten different feature selection algorithms were applied and used to rank the most important genes in S. aureus biofilms. Finally, an optimal set of 36 genes are presented as candidate genes in biofilm formation or development while throwing light on the novel roles of an acyl-CoA thioesterase enzyme and 10 hypothetical proteins in biofilms. The relevance of the identified gene set was further validated by building five different classification models using SVM, RF, kNN, NB and DT algorithms that were compared with models built from other relevant gene sets and by reviewing the functional role of 25 previously known genes in biofilm development. The study combines meta-analysis of differential expression with supervised machine learning strategies and feature selection for the first time to identify and validate a discriminatory set of genes important in biofilms of S. aureus. The functional roles of the identified genes predicted to be important in biofilms are further scrutinized and can be considered as a signature target list to develop anti-biofilm therapeutics in S. aureus.}, } @article {pmid33386870, year = {2021}, author = {Heydari, S and Siavoshi, F and Sarrafnejad, A and Malekzadeh, R}, title = {Coniochaeta fungus benefits from its intracellular bacteria to form biofilm and defend against other fungi.}, journal = {Archives of microbiology}, volume = {203}, number = {4}, pages = {1357-1366}, pmid = {33386870}, issn = {1432-072X}, mesh = {Antifungal Agents/metabolism/pharmacology ; Ascomycota/metabolism/*physiology/ultrastructure ; Biofilms/*growth & development ; Candida/drug effects ; Cytoplasm/microbiology ; Microbial Interactions ; Microscopy, Electron, Scanning ; Nocardia/isolation & purification/*physiology/ultrastructure ; }, abstract = {During cultivation of a gastric fungus, Coniochaeta polymorpha, growth of Nocardia colonies on top of the fungal culture raised the question whether bacteria originated from inside of fungus. In this study, the likelihood of intracellular origin of bacteria as well as interaction of two microorganisms was assessed. Fluorescence and electron microscopy showed occurrence of several bacterial cells in fungal cytoplasm. A thick biofilm was observed on the surface of co-culture compared with thin one on bacterial and none on fungal monocultures. Field emission scanning electron microscopy (FESEM) micrographs of co-culture showed a dense network of fungal and bacterial cells embedded in a slime-like layer. Dual cultures revealed antagonistic activity of both fungus and bacteria against three Candida species. These findings indicate that Nocardia isolate identified in this study originated from the inside of fungus C. polymorpha. Intracellular bacteria could benefit the fungal host by producing a rigid biofilm and an antifungal compound.}, } @article {pmid33386072, year = {2021}, author = {Mulya, E and Waturangi, DE}, title = {Screening and quantification of anti-quorum sensing and antibiofilm activity of Actinomycetes isolates against food spoilage biofilm-forming bacteria.}, journal = {BMC microbiology}, volume = {21}, number = {1}, pages = {1}, pmid = {33386072}, issn = {1471-2180}, support = {RISTEKDIKTI 2019//Kementerian Riset Teknologi Dan Pendidikan Tinggi Republik Indonesia/ ; }, mesh = {Actinobacteria/*metabolism ; Anti-Bacterial Agents/isolation & purification/pharmacology ; Bacillus cereus/drug effects/growth & development ; Bacillus subtilis/drug effects/growth & development ; Bacteria/drug effects/*growth & development ; Biofilms/drug effects ; Biological Factors/isolation & purification/*pharmacology ; Chromobacterium/drug effects/growth & development/*physiology ; Food Microbiology ; Indonesia ; Microbial Viability/drug effects ; Quorum Sensing/*drug effects ; Shewanella putrefaciens/drug effects/growth & development ; }, abstract = {BACKGROUND: Biofilms can form in many industries, one of them is the food industry. The formation of biofilms in this industry could cause immense economic losses and endanger public health. Biofilms formation is mainly triggered by quorum sensing. Therefore, inhibition of quorum sensing could be an innovative approach to inhibit the formation of biofilms. One way to inhibit quorum sensing is by using anti-quorum sensing compounds. Actinomycetes are a group of bacteria that is acknowledged to produce these compounds.

RESULTS: There were eight crude extracts of Actinomycetes isolates that showed promising anti-quorum sensing activity against Chromobacterium violaceum. The concentration of the crude extracts was 20 mg/mL. All the crude extracts showed no antibacterial activity against food spoilage bacteria, except for crude extracts of isolate 18 PM that showed antibacterial activity against Bacillus subtilis. They also showed various antibiofilm activity, both inhibition and destruction. The highest inhibition and destruction activity sequentially was done by crude extracts of isolate 12 AC with 89.60% against Bacillus cereus and crude extracts of isolate SW03 with 93.06% against Shewanella putrefaciens.

CONCLUSIONS: Actinomycetes isolates that isolated from different regions in Indonesia can be used as potential candidates to overcome biofilms formed by food spoilage bacteria using their ability to produce anti-quorum sensing compounds.}, } @article {pmid33385847, year = {2021}, author = {Carafa, R and Lorenzo, NE and Llopart, JS and Kumar, V and Schuhmacher, M}, title = {Characterization of river biofilm responses to the exposure with heavy metals using a novel micro fluorometer biosensor.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {231}, number = {}, pages = {105732}, doi = {10.1016/j.aquatox.2020.105732}, pmid = {33385847}, issn = {1879-1514}, mesh = {Biofilms/drug effects ; *Biosensing Techniques ; Chlorophyta/cytology/drug effects ; Diatoms/cytology/drug effects ; *Environmental Exposure ; Environmental Monitoring ; Fluorescence ; Fluorometry/*instrumentation ; Metals, Heavy/*toxicity ; Periphyton/drug effects ; Photochemical Processes ; Photosynthesis/drug effects ; Rivers/*chemistry ; Water Pollutants, Chemical/toxicity ; Water Pollution/analysis ; Water Quality ; }, abstract = {River biofilms are a suitable indicator of toxic stress in aquatic ecosystems commonly exposed to various anthropogenic pollutants from industrial, domestic, and agricultural sources. Among these pollutants, heavy metals are of particular concern as they are known to interfere with various physiological processes of river biofilm, directly or indirectly related to photosynthetic performance. Nevertheless, only limited toxicological data are available on the mechanisms and toxicodynamics of heavy metals in biofilms. Pulse Amplitude Modulated (PAM) fluorometry is a rapid, non-disruptive, well-established technique to monitor toxic responses on photosynthetic performance, fluorescence-kinetics, and changes in yield in other non-photochemical processes. In this study, a new micro-PAM-sensor was tested to assess potential acute and chronic effects of heavy metals in river biofilm. Toxicity values across the three parameters considered in this study (photosynthetic yield YII, non-photochemical quenching NPQ, and basal fluorescence F0) were comparable, as determined EC50 were within one order of magnitude (EC50 ∼1-10 mg L[-1]). However, the stimulation of NPQ was more clearly associated with early acute effects, especially in illuminated samples, while depression of YII and F0 were more prevalent in chronic tests. These results have implications for the development of functional indicators for the biomonitoring of aquatic health, in particular for the use of river biofilm as a bioindicator of water quality. In conclusion, the approach proposed seems promising to characterize and monitor the exposure and impact of heavy metals on river periphyton communities. Furthermore, this study provides a fast, highly sensitive, inexpensive, and accurate laboratory method to test effects of pollutants on complex periphyton communities that can also give insights regarding the probable toxicological mechanisms of heavy metals on photosynthetic performance in the river biofilm.}, } @article {pmid33385805, year = {2021}, author = {Iwata, Y and Sakai, N and Yoneda, I and Senda, Y and Sakai-Takemori, Y and Oshima, M and Nakagawa-Yoneda, S and Ogura, H and Sato, K and Minami, T and Kitajima, S and Toyama, T and Yamamura, Y and Miyagawa, T and Hara, A and Shimizu, M and Furuichi, K and Matsushima, K and Wada, T}, title = {D-Serine inhibits the attachment and biofilm formation of methicillin-resistant Staphylococcus aureus.}, journal = {Biochemical and biophysical research communications}, volume = {537}, number = {}, pages = {50-56}, doi = {10.1016/j.bbrc.2020.12.078}, pmid = {33385805}, issn = {1090-2104}, mesh = {Animals ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Catheters/microbiology ; Disease Models, Animal ; Down-Regulation/drug effects/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*physiology ; Mice, Inbred BALB C ; Peritonitis/microbiology/pathology ; Polyvinyl Chloride ; Serine/*pharmacology ; }, abstract = {INTRODUCTION: Although therapeutic agents for methicillin-resistant Staphylococcus aureus (MRSA) are clinically available, MRSA infection is still a life-threatening disease. Bacterial attachment and biofilm formation contribute significantly to the initiation of MRSA infection. Controlling MRSA's attachment and biofilm formation might reduce the frequency of MRSA infection. According to recent data, some amino acids can reduce MRSA's attachment on plates; however, their precise inhibitory mechanisms remain unclear. Therefore, we explored the effect of the amino acids on bacterial adhesion and biofilm formation in vitro and in vivo MRSA infection models.

METHODS: We tested the inhibitory effect of amino acids on MRSA and Escherichia coli (E. coli) in the attachment assay. Moreover, we evaluated the therapeutic potential of amino acids on the in vivo catheter infection model.

RESULTS: Among the amino acids, D-Serine (D-Ser) was found to reduce MRSA's ability to attach on plate assay. The proliferation of MRSA was not affected by the addition of D-Ser; thus, D-Ser likely only played a role in preventing attachment and biofilm formation. Then, we analyzed the expression of genes related to attachment and biofilm formation. D-Ser was found to reduce the expressions of AgrA, SarS, IcaA, DltD, and SdrD. Moreover, the polyvinyl chloride catheters treated with D-Ser had fewer MRSA colonies. D-Ser treatment also reduced the severity of infection in the catheter-induced peritonitis model. Moreover, D-Ser reduced the attachment ability of E. coli.

CONCLUSION: D-Ser inhibits the attachment and biofilm formation of MRSA by reducing the expression of the related genes. Also, the administration of D-Ser reduces the severity of catheter infection in the mouse model. Therefore, D-Ser may be a promising therapeutic option for MRSA as well as E. coli infection.}, } @article {pmid33385721, year = {2021}, author = {Bouteh, E and Ahmadi, N and Abbasi, M and Torabian, A and van Loosdrecht, MCM and Ducoste, J}, title = {Biodegradation of organophosphorus pesticides in moving bed biofilm reactors: Analysis of microbial community and biodegradation pathways.}, journal = {Journal of hazardous materials}, volume = {408}, number = {}, pages = {124950}, doi = {10.1016/j.jhazmat.2020.124950}, pmid = {33385721}, issn = {1873-3336}, mesh = {Acinetobacter ; Biofilms ; Bioreactors ; *Microbiota ; *Pesticides ; Phylogeny ; Waste Disposal, Fluid ; }, abstract = {We investigated the performance of a lab-scale moving bed biofilm reactor (MBBR) with respect to general bioconversion processes and biotransformation of two commonly used organophosphorus pesticides, Chlorpyrifos (CHL) and Malathion (MAL). The reactor was operated for 300 days under different organic loads by changing hydraulic retention time (HRT). The decrease in organic load resulted in the formation of a thinner biofilm and the growth of more biomass in the bulk, which greatly shifted bioconversion processes. The low organic loading supported more nitrification in the reactor, but an opposite trend was observed for denitrification, which was enhanced at higher organic loading where the formation of anoxic zones in the thick biofilm was favored. 70% and 55% removal corresponding to 210 and 165 µg/m[2]/d occurred for MAL and CHL, respectively, at an HRT of 3 h and progressively increased with higher HRTs. Phylogenetic analysis revealed a shift in composition and abundance of taxa throughout the reactor operation where lower loading rate supported the growth of a more diverse and evenly distributed community. The analysis also highlighted the dominance of heterotrophic communities such as Flavobacterium and Acinetobacter johnsonii, which could be involved in the biotransformation of CHL and MAL through co-metabolism.}, } @article {pmid33385688, year = {2021}, author = {Qin, H and Cao, H and Zhao, Y and Zhu, C and Cheng, T and Wang, Q and Peng, X and Cheng, M and Wang, J and Jin, G and Jiang, Y and Zhang, X and Liu, X and Chu, PK}, title = {Corrigendum to "In vitro and in vivo anti-biofilm effects of silver nanoparticles immobilized on titanium" [Biomaterials (2014) 9114-9125].}, journal = {Biomaterials}, volume = {269}, number = {}, pages = {120615}, doi = {10.1016/j.biomaterials.2020.120615}, pmid = {33385688}, issn = {1878-5905}, } @article {pmid33385683, year = {2021}, author = {Gong, H and He, L and Zhao, Z and Mao, X and Zhang, C}, title = {The specific effect of (R)-(+)-pulegone on growth and biofilm formation in multi-drug resistant Escherichia coli and molecular mechanisms underlying the expression of pgaABCD genes.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {134}, number = {}, pages = {111149}, doi = {10.1016/j.biopha.2020.111149}, pmid = {33385683}, issn = {1950-6007}, mesh = {Amidohydrolases/genetics ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Cyclohexane Monoterpenes/*pharmacology ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli K12/*drug effects/genetics/growth & development ; Escherichia coli Proteins/*genetics ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; }, abstract = {E. coli is associated with high rates of infection and resistance to drugs not only in China but also the rest of the world. In addition, the number of E. coli biofilm infections continue to increase with time. Notably, biofilms are attractive targets for the prevention of infections caused by multidrug-resistant bacteria. Moreover, the pgaABCD-encoded Poly-β-1,6-N-acetyl-d-glucosamine (PNAG) plays an important role in biofilm formation. Therefore, this study aimed to explore the specific effect of the (R)-(+)-pulegone (PU) on growth and biofilm formation in multi-drug resistant E. coli. The molecular mechanisms involved were also examined. The results showed that PU had significant antibacterial and antibiofilm formation activity against E. coli K1, with MIC and MBC values of 23.68 and 47.35 mg/mL, respectively. On the other hand, the maximum inhibition rate for biofilm formation in the bacterium was 52.36 % at 94.70 mg/mL of PU. qRT-PCR data showed that PU significantly down-regulated expression of the pgaABCD genes (P < 0.05). PU was also broadly effective against biofilm formation in MG1655 and MG1655/ΔpgaABCD, exhibiting the maximum inhibition rates were 98.23 % and 93.35 %, respectively. In addition, PU destroyed pre-formed mature biofilm in both MG1655 and MG1655/ΔpgaABCD about 95.03 % and 92.4 %, respectively. The study therefore verified that pgaA was a potential and key target for PU in E. coli although it was not the only one. Overall, the findings indicated that PU is a potential and novel inhibitor of drug resistance, This therefore gives insights on new ways of preventing and treating biofilm-associated infections in the food industry as well as in clinical practice.}, } @article {pmid33383978, year = {2020}, author = {Shokeen, B and Park, J and Duong, E and Rambhia, S and Paul, M and Weinberg, A and Shi, W and Lux, R}, title = {Correction: Shokeen, B., et al. Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation. Microorganisms 2020, 8, 70.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33383978}, issn = {2076-2607}, abstract = {The authors wish to make the following corrections to this paper [...].}, } @article {pmid33383728, year = {2020}, author = {Nuppunen-Puputti, M and Kietäväinen, R and Purkamo, L and Rajala, P and Itävaara, M and Kukkonen, I and Bomberg, M}, title = {Rock Surface Fungi in Deep Continental Biosphere-Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33383728}, issn = {2076-2607}, support = {NF_DEEPFUN//Maj and Tor Nessling Foundation/ ; 133348/2009//Academy of Finland/ ; MIMOSA//The Finnish Research Programme on Nuclear Waste Management/ ; BIKES//The Finnish Research Programme on Nuclear Waste Management/ ; }, abstract = {Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii.}, } @article {pmid33383260, year = {2021}, author = {Sivaranjani, M and Liu, F and White, AP}, title = {Synergistic activity of tetrasodium EDTA, ethanol and chlorhexidine hydrochloride against planktonic and biofilm cells of clinically relevant pathogens.}, journal = {Journal of global antimicrobial resistance}, volume = {24}, number = {}, pages = {148-157}, doi = {10.1016/j.jgar.2020.12.002}, pmid = {33383260}, issn = {2213-7173}, mesh = {Biofilms ; *Chlorhexidine/pharmacology ; Edetic Acid/pharmacology ; Ethanol/pharmacology ; *Plankton ; }, abstract = {OBJECTIVES: Biofilms associated with implantable medical devices and wounds are clinically relevant, often requiring repeated use of antibiotics without success. A search for non-antibiotic antimicrobial and antibiofilm solutions is warranted, in line with antimicrobial stewardship. Our study aimed to evaluate the broad-spectrum antimicrobial efficacy of tetrasodium EDTA, ethanol and chlorhexidine hydrochloride (HCl) alone and in combination against clinically relevant planktonic and biofilm cells of bacterial and fungal pathogens.

METHODS: MICs and MBCs were determined for tetrasodium EDTA, ethanol and chlorhexidine HCl against planktonic cells of test pathogens. The MBEC Assay® biofilm inoculator device was used to evaluate the biofilm eradication ability of test antimicrobials alone and in combination against clinically relevant pathogens. The checkerboard microbroth dilution assay was performed to analyze the synergism between test antimicrobials.

RESULTS: Against planktonic cells, the combination of tetrasodium EDTA with ethanol or chlorhexidine HCl resulted in synergistic to indifferent activity, with no antagonism observed. Against mature biofilms, all combinations were synergistic. The MBEC of each test antimicrobial was decreased from 4- to -64-fold when used in combination as compared to when agents were used alone. We optimised the concentration of antimicrobials to achieve rapid eradication of pre-formed biofilms. A triple combination of 3% tetrasodium EDTA, 20% ethanol and 2.5 μg/mL chlorhexidine HCl completely eradicated 48-h-old biofilms of all test strains within 2 h.

CONCLUSION: All three antimicrobial agents can be used together for prevention and treatment of biofilms and biofilm-related infections. The observed in vitro efficacy should be tested further through in vivo and clinical studies.}, } @article {pmid33382839, year = {2020}, author = {Montoya-Hinojosa, E and Bocanegra-Ibarias, P and Garza-González, E and Alonso-Ambriz, ÓM and Salazar-Mata, GA and Villarreal-Treviño, L and Pérez-Alba, E and Camacho-Ortiz, A and Morfín-Otero, R and Rodríguez-Noriega, E and Flores-Treviño, S}, title = {Discrimination of biofilm-producing Stenotrophomonas maltophilia clinical strains by matrix-assisted laser desorption ionization-time of flight.}, journal = {PloS one}, volume = {15}, number = {12}, pages = {e0244751}, pmid = {33382839}, issn = {1932-6203}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cross Infection/*microbiology ; Humans ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Stenotrophomonas maltophilia/genetics/*isolation & purification ; }, abstract = {Stenotrophomonas maltophilia is a Gram-negative drug-resistant pathogen responsible for healthcare-associated infections. The aim was to search for biomarker peaks that could rapidly detect biofilm production in S. maltophilia clinical isolates obtained from two tertiary care hospitals in Mexico. Isolates were screened for the presence of biofilm-associated genes, in which the fsnR gene was associated with biofilm production (p = 0.047), whereas the rmlA+ genotype was associated with the rpfF- genotype (p = 0.017). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectra comparison yielded three potential biomarker peaks (4661, 6074, and 6102 m/z) of biofilm-producing rmlA+ and rpfF- genotypes with >90% sensitivity (p<0.001). MALDI-TOF MS analyses showed a correlation between the relative abundance of 50S ribosomal proteins (L30 and L33) and the presence of the fnsR, rmlA and rpfF-2 genes, suggested to play a role in biofilm formation. Isolates obtained in the intensive care unit showed low clonality, suggesting no transmission within the hospital ward. The detection of biomarkers peaks by MALDI-TOF MS could potentially be used to early recognize and discriminate biofilm-producing S. maltophilia strains and aid in establishing appropriate antibiotic therapy.}, } @article {pmid33381752, year = {2020}, author = {Townsend, EM and Moat, J and Jameson, E}, title = {CAUTI's next top model - Model dependent Klebsiella biofilm inhibition by bacteriophages and antimicrobials.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100038}, pmid = {33381752}, issn = {2590-2075}, abstract = {Klebsiella infections, including catheter associated urinary tract infections, are a considerable burden on health care systems. This is due to their difficulty to treat, caused by antimicrobial resistance and their ability to form biofilms. In this study, we investigated the use of a Klebsiella phage cocktail to reduce biofilm viability. We used two methodologies to investigate this, a standard 96-well plate assay and a more complicated Foley catheter-based model. The phage cocktail was used alone and in combination with clinically relevant antibiotic treatments. Viability was measured by both a resazurin based stain and colony forming unit counts, of cells sloughed off from the biofilm. We showed that phage infection dynamics and host survival vary significantly in different standard laboratory media, presumably due to the expression of different surface receptors and capsule composition by the bacteria effecting phage binding. This underscores the importance of a realistic model for developing phage therapy. We demonstrate that bacteriophage-based treatments are a viable option for preventing Klebsiella colonisation and biofilm formation on urinary catheters. Phage cocktails were able to significantly reduce the amount of biofilm that formed when they were present during early biofilm formation. The phages used in this study were unable to significantly reduce a pre-formed mature biofilm, despite encoding depolymerases. Phages applied together with antimicrobial treatments, showed synergistic interactions, in some cases the combined treatment was much more effective than antimicrobial treatments alone. We show that phage cocktails have the potential to prevent Klebsiella biofilms in catheters, if used early or as a preventative treatment and will work well alongside standard antibiotics in the treatment of catheter-associated urinary tract infections (CAUTI).}, } @article {pmid33381751, year = {2020}, author = {Harrington, NE and Sweeney, E and Harrison, F}, title = {Building a better biofilm - Formation of in vivo-like biofilm structures by Pseudomonas aeruginosa in a porcine model of cystic fibrosis lung infection.}, journal = {Biofilm}, volume = {2}, number = {}, pages = {100024}, pmid = {33381751}, issn = {2590-2075}, support = {MR/R001898/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Pseudomonas aeruginosa biofilm infections in the cystic fibrosis (CF) lung are highly resistant to current antimicrobial treatments and are associated with increased mortality rates. The existing models for such infections are not able to reliably mimic the clinical biofilms observed. We aimed to further optimise an ex vivo pig lung (EVPL) model for P. aeruginosa CF lung infection that can be used to increase understanding of chronic CF biofilm infection. The EVPL model will facilitate discovery of novel infection prevention methods and treatments, and enhanced exploration of biofilm architecture. We investigated purine metabolism and biofilm formation in the model using transposon insertion mutants in P. aeruginosa PA14 for key genes: purD, gacA and pelA. Our results demonstrate that EVPL recapitulates a key aspect of in vivo P. aeruginosa infection metabolism, and that the pathogen forms a biofilm with a clinically realistic structure not seen in other in vitro studies. Two pathways known to be required for in vivo biofilm infection - the Gac regulatory pathway and production of the Pel exopolysaccharide - are essential to the formation of this mature, structured biofilm on EVPL tissue. We propose the high-throughput EVPL model as a validated biofilm platform to bridge the gap between in vitro work and CF lung infection.}, } @article {pmid33379333, year = {2020}, author = {Young, T and Alshanta, OA and Kean, R and Bradshaw, D and Pratten, J and Williams, C and Woodall, C and Ramage, G and Brown, JL}, title = {Candida albicans as an Essential "Keystone" Component within Polymicrobial Oral Biofilm Models?.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33379333}, issn = {2076-2607}, abstract = {Background: Existing standardized biofilm assays focus on simple mono-species or bacterial-only models. Incorporating Candida albicans into complex biofilm models can offer a more appropriate and relevant polymicrobial biofilm for the development of oral health products. Aims: This study aimed to assess the importance of interkingdom interactions in polymicrobial oral biofilm systems with or without C. albicans, and test how these models respond to oral therapeutic challenges in vitro. Materials and Methods: Polymicrobial biofilms (two models containing 5 and 10 bacterial species, respectively) were created in parallel in the presence and absence of C. albicans and challenged using clinically relevant antimicrobials. The metabolic profiles and biomasses of these complex biofilms were estimated using resazurin dye and crystal violet stain, respectively. Quantitative PCR was utilized to assess compositional changes in microbial load. Additional assays, for measurements of pH and lactate, were included to monitor fluctuations in virulence "biomarkers." Results: An increased level of metabolic activity and biomass in the presence of C. albicans was observed. Bacterial load was increased by more than a factor of 10 in the presence of C. albicans. Assays showed inclusion of C. albicans impacted the biofilm virulence profiles. C. albicans did not affect the biofilms' responses to the short-term incubations with different treatments. Conclusions: The interkingdom biofilms described herein are structurally robust and exhibit all the hallmarks of a reproducible model. To our knowledge, these data are the first to test the hypothesis that yeasts may act as potential "keystone" components of oral biofilms.}, } @article {pmid33379305, year = {2020}, author = {Papaianni, M and Ricciardelli, A and Casillo, A and Corsaro, MM and Borbone, F and Della Ventura, B and Velotta, R and Fulgione, A and Woo, SL and Tutino, ML and Parrilli, E and Capparelli, R}, title = {The Union Is Strength: The Synergic Action of Long Fatty Acids and a Bacteriophage against Xanthomonas campestris Biofilm.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33379305}, issn = {2076-2607}, abstract = {Xanthomonas campestris pv. campestris is known as the causative agent of black rot disease, which attacks mainly crucifers, severely lowering their global productivity. One of the main virulence factors of this pathogen is its capability to penetrate and form biofilm structures in the xylem vessels. The discovery of novel approaches to crop disease management is urgent and a possible treatment could be aimed at the eradication of biofilm, although anti-biofilm approaches in agricultural microbiology are still rare. Considering the multifactorial nature of biofilm, an effective approach against Xanthomonas campestris implies the use of a multi-targeted or combinatorial strategy. In this paper, an anti-biofilm strategy based on the use of fatty acids and the bacteriophage (Xccφ1)-hydroxyapatite complex was optimized against Xanthomonas campestris mature biofilm. The synergic action of these elements was demonstrated and the efficient removal of Xanthomonas campestris mature biofilm was also proven in a flow cell system, making the proposed approach an effective solution to enhance plant survival in Xanthomonas campestris infections. Moreover, the molecular mechanisms responsible for the efficacy of the proposed treatment were explored.}, } @article {pmid33378697, year = {2021}, author = {Thulshan Jayathilaka, EHT and Liyanage, TD and Rajapaksha, DC and Dananjaya, SHS and Nikapitiya, C and Whang, I and De Zoysa, M}, title = {Octominin: An antibacterial and anti-biofilm peptide for controlling the multidrug resistance and pathogenic Streptococcus parauberis.}, journal = {Fish & shellfish immunology}, volume = {110}, number = {}, pages = {23-34}, doi = {10.1016/j.fsi.2020.12.017}, pmid = {33378697}, issn = {1095-9947}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial ; Fish Diseases/prevention & control ; Microbial Sensitivity Tests/veterinary ; Microbial Viability/*drug effects ; Microscopy, Electron, Scanning ; Peptide Fragments/*pharmacology ; Streptococcal Infections/prevention & control/veterinary ; Streptococcus/*drug effects/physiology/ultrastructure ; }, abstract = {Streptococcus parauberis is a pathogenic gram-positive bacterium that causes streptococcosis infection in fish. Since S. parauberis is becoming resistant to multiple antibiotics, the development of alternatives, such as antimicrobial peptides, has gained great attention. Octominin, derived from the defense protein of Octopus minor, showed a significant antimicrobial activity against multidrug resistance S. parauberis, with a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 50 and 100 μg/mL, respectively. Furthermore, time-kill kinetics, agar diffusion, and bacterial viability assays confirmed the concentration-dependent antibacterial activity of Octominin against S. parauberis. Field emission scanning electron microscopy analysis showed morphological and ultra-structural changes in S. parauberis upon Octominin treatment. Moreover, Octominin treatment demonstrated changes in membrane permeability, induced reactive oxygen species (ROS), and its binding ability to genomic DNA, suggesting its strong bactericidal activity with multiple modes of action. We confirmed the inhibition of biofilm formation and the eradication of existing biofilms in a concentration-dependent manner. Additionally, Octominin on S. parauberis at transcriptional level exhibited downregulation of membrane formation (pgsA and cds1), DNA repairing (recF), biofilm formation (pgaB and epsF) genes, while upregulation of ROS detoxification (sodA) and DNA protecting (ahpF) related genes. An in vivo study confirmed a significantly (P < 0.05) higher relative percentage survival in Octominin-treated larval zebrafish exposed to S. parauberis (93.3%) compared to the control group (20.0%). Collectively, our results confirm that Octominin could be a potential antibacterial and anti-biofilm agent against S. parauberis.}, } @article {pmid33378620, year = {2021}, author = {Sadeghi, Z and Masullo, M and Cerulli, A and Nazzaro, F and Farimani, MM and Piacente, S}, title = {Terpenoid Constituents of Perovskia artemisioides Aerial Parts with Inhibitory Effects on Bacterial Biofilm Growth.}, journal = {Journal of natural products}, volume = {84}, number = {1}, pages = {26-36}, doi = {10.1021/acs.jnatprod.0c00832}, pmid = {33378620}, issn = {1520-6025}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Humans ; Plant Components, Aerial/*chemistry ; Plant Extracts ; Salvia/*chemistry ; Sesquiterpenes/chemistry/isolation & purification/*pharmacology ; Terpenes/chemistry/isolation & purification/*pharmacology ; }, abstract = {Perovskia artemisioides is a perennial and aromatic plant distributed in the Baluchestan region of Iran. In the present work, an n-hexane extract of P. artemisioides aerial parts showed excellent capabilities to both inhibit the formation of biofilms by different Gram-positive and Gram-negative pathogens and block the cell metabolism within microbial biofilms. To correlate the activity of the extract with the biologically active compounds present, first an analytical approach based on LC-HRMS/MS[n] was carried out. The metabolite profile obtained guided the isolation of 21 compounds, among which two sesquiterpenes (8 and 9) and one diterpene (10) were found to be new. The antimicrobial activity of the isolated compounds was evaluated by determining how they were able not only to reduce the growth of different Gram-positive and Gram-negative human bacteria and phytopathogens but also to inhibit the formation of biofilms by these bacteria and affect the metabolism of microbial cells present within the biofilms. With the aim of correlating the activity exhibited by the extract with the concentration levels of the constituent compounds, a quantitative determination was carried out by an analytical approach based on LC-ESI/QTrap/MS.}, } @article {pmid33378466, year = {2020}, author = {Park, KH and Han, SJ and Choi, S and Kim, KS and Park, S and Park, JH}, title = {Surface Roughness on the Slots and Wings of Various Ceramic Self-Ligating Brackets and their Potential Concern on Biofilm Formation.}, journal = {The Journal of clinical pediatric dentistry}, volume = {44}, number = {6}, pages = {451-458}, doi = {10.17796/1053-4625-44.6.10}, pmid = {33378466}, issn = {1053-4628}, mesh = {Biofilms ; Ceramics ; Dental Alloys ; Friction ; Humans ; Materials Testing ; Orthodontic Appliance Design ; *Orthodontic Brackets ; Orthodontic Wires ; Stainless Steel ; Surface Properties ; }, abstract = {OBJECTIVE: The surface roughness of various orthodontic materials could affect biofilm formation and friction. The purpose of this study was to examine the surface roughness and chemical composition of the slots and wings of several ceramic self-ligating brackets.

STUDY DESIGN: Four types of ceramic self-ligating brackets were separated into experimental groups (DC, EC, IC, and QK) while a metal self-ligating bracket (EM) was used as the control group. Atomic force microscopy and energy-dispersive x-ray spectroscope were used to examine the surface roughness and chemical composition of each bracket slot and wing.

RESULTS: The control group was made of ferrum and chrome while all the experimental groups were comprised of aluminum and oxide. There was a statistically significant difference in the roughness average (Sa) among the various self-ligating brackets (p< 0.001 in slots and p<0.01 in the wing). The slots in the EC group had the lowest Sa, followed by the DC, IC, control, and QK groups. The wings in the IC group had the lowest Sa, followed by the EC, DC, control, and QK groups.

CONCLUSIONS: There is a significant difference in the surface roughness of the slots and wings among several types of ceramic self-ligating brackets.}, } @article {pmid33378420, year = {2021}, author = {Rezende-Pereira, G and Albuquerque, JP and Souza, MC and Nogueira, BA and Silva, MG and Hirata, R and Mattos-Guaraldi, AL and Duarte, RS and Neves, FPG}, title = {Biofilm Formation on Breast Implant Surfaces by Major Gram-Positive Bacterial Pathogens.}, journal = {Aesthetic surgery journal}, volume = {41}, number = {10}, pages = {1144-1151}, doi = {10.1093/asj/sjaa416}, pmid = {33378420}, issn = {1527-330X}, support = {//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil/ ; }, mesh = {Biofilms ; *Breast Implants/adverse effects ; Gram-Positive Bacteria ; Microscopy, Electron, Scanning ; Staphylococcus aureus ; Staphylococcus epidermidis ; }, abstract = {BACKGROUND: Bacterial biofilm on surfaces of mammary implants is a predisposing factor for several outcomes. Because Gram-positive bacteria are potential agents of biomaterial-associated infections (BAIs), their abilities to form biofilm on breast implants should be elucidated.

OBJECTIVES: The aim of this study was to evaluate biofilm formation on different mammary prosthesis surfaces by major Gram-positive bacterial pathogens involved in BAIs.

METHODS: We initially evaluated biofilm formation on polystyrene plates with and without fibrinogen or collagen for 1 reference strain and 1 clinical isolate of Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. We also tested the ability of clinical isolates to form biofilm on 4 different implant surfaces: polyurethane foam and smooth, microtextured, and standard textured silicone. Biofilm structure and cell viability were observed by scanning electron microscopy and confocal laser scanning microscopy.

RESULTS: All strains showed strong biofilm formation on polystyrene. After fibrinogen or collagen treatment, biofilm formation varied. With fibrinogen, reference strains of S. aureus and S. pyogenes increased biofilm formation (P < 0.05). Reference strains of all species and the clinical isolate of S. pyogenes increased biofilm formation after collagen treatment (P < 0.05). In general, S. aureus showed higher capacity to produce biofilm. Scanning electron microscopy showed that biofilm attached to all surfaces tested, with the presence of extracellular polymeric substances and voids. Viable cells were more frequent for E. faecalis and S. pyogenes.

CONCLUSIONS: All species produced biofilm on all prosthesis surfaces and under different conditions. Micrographies indicated thicker bacterial biofilm formation on microtextured and/or standard textured silicone by all species, except E. faecalis.}, } @article {pmid33376858, year = {2020}, author = {Khan, MF and Husain, FM and Zia, Q and Ahmad, E and Jamal, A and Alaidarous, M and Banawas, S and Alam, MM and Alshehri, BA and Jameel, M and Alam, P and Ahamed, MI and Ansari, AH and Ahmad, I}, title = {Anti-quorum Sensing and Anti-biofilm Activity of Zinc Oxide Nanospikes.}, journal = {ACS omega}, volume = {5}, number = {50}, pages = {32203-32215}, pmid = {33376858}, issn = {2470-1343}, abstract = {This study evaluates the impact of two separate incubation periods (4 and 6 weeks) on the morphology of sol-gel-fabricated ZnO nanospikes (ZNs), that is, ZN1 and ZN2, respectively. We further analyzed the inhibitory effects of ZN1 and ZN2 on quorum sensing (QS) and biofilm formation in Pseudomonas aeruginosa (PAO1) and Chromobacterium violaceum (strains 12472 and CVO26). The size of the synthesized ZNs was in the range of 40-130 nm, and finer nanoparticles were synthesized after an incubation period of 6 weeks. Treatment with ZNs decreased the production of violacein in the pathogen without affecting the bacterial growth, which indicated that ZNs inhibited the QS signaling regulated by N-acyl homoserine lactone. ZN2 had a higher inhibitory action on the virulence factor productivity than ZN1. Furthermore, ZN2-treated cells displayed a substantial decrease in azocasein-degrading protease activity (80%), elastase activity (83%), and pyocyanin production (85%) relative to untreated P. aeruginosa PAO1 cells. Treatment with ZN2 decreased swarming motility and exopolysaccharide production by 89 and 85%, respectively. ZN2 was effective against both the las & pqs systems of P. aeruginosa and exhibited broad-spectrum activity. Additionally, ZN2 was more efficient in inhibiting the biofilm formation at the attachment stage than ZN1. These findings revealed that in P. aeruginosa, ZN2 demonstrated inhibitory effects on QS as well as on the development of biofilms. Thus, ZN2 can be potentially used to treat drug-resistant P. aeruginosa infections.}, } @article {pmid33375734, year = {2020}, author = {Białucha, A and Gospodarek-Komkowska, E and Kwiecińska-Piróg, J and Skowron, K}, title = {Influence of Selected Factors on Biofilm Formation by Salmonella enterica Strains.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33375734}, issn = {2076-2607}, abstract = {Biofilm formed by S. enterica on the surface of gallstones or biomaterials promotes the development and spread of chronic infection. The aim of the study was to assess biofilm formation on the surface of polystyrene depending on nutritional conditions and the effect of 0.5, 1.0, and 2.0% glucose and 3.0% bile and sub-inhibitory concentrations of ampicillin on biofilm formation of S. enterica. Sixty-nine clinical strains of S. enterica isolated from feces (92.8%) and blood (7.2%) collected from patients (66.7%) and carriers (33.3%) were used in the study. Assessment of forming 24-h biofilm by these strains was performed on the surface of polystyrene 96-well plates at 37 °C. In this study, it was indicated that 1.0% glucose and 3.0% bovine bile inhibit biofilm formation. Biofilm formation was inhibited in all examined sub-MIC of ampicillin. Biofilm formation is varied in different conditions, depending on the serovar.}, } @article {pmid33375552, year = {2020}, author = {Machado, TS and Pinheiro, FR and Andre, LSP and Pereira, RFA and Correa, RF and de Mello, GC and Ribeiro, TAN and Penna, B and Sachs, D and Aguiar-Alves, F}, title = {Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm.}, journal = {Toxins}, volume = {13}, number = {1}, pages = {}, pmid = {33375552}, issn = {2072-6651}, support = {CAPES-001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/International ; FAPERJ - 110.110/2014//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/International ; UFF-FOPESQ-001//Universidade Federal Fluminense/International ; }, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Female ; Gene Expression Regulation, Bacterial ; Humans ; Male ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus/genetics/*isolation & purification ; Middle Aged ; Nose/*microbiology ; Staphylococcal Infections/*microbiology ; Virulence Factors/genetics/*metabolism ; Young Adult ; }, abstract = {Hospitalizations related to Methicillin-resistant Staphylococcus aureus (MRSA) are frequent, increasing mortality and health costs. In this way, this study aimed to compare the genotypic and phenotypic characteristics of MRSA isolates that colonize and infect patients seen at two hospitals in the city of Niterói-Rio de Janeiro, Brazil. A total of 147 samples collected between March 2013 and December 2015 were phenotyped and genotyped to identify the protein A (SPA) gene, the mec staphylococcal chromosomal cassette (SCCmec), mecA, Panton-Valentine Leucocidin (PVL), icaC, icaR, ACME, and hla virulence genes. The strength of biofilm formation has also been exploited. The prevalence of SCCmec type IV (77.1%) was observed in the colonization group; however, in the invasive infection group, SCCmec type II was prevalent (62.9%). The Multilocus Sequence Typing (MLST), ST5/ST30, and ST5/ST239 analyses were the most frequent clones in colonization, and invasive infection isolates, respectively. Among the isolates selected to assess the ability to form a biofilm, 51.06% were classified as strong biofilm builders. Surprisingly, we observed that isolates other than the Brazilian Epidemic Clone (BEC) have appeared in Brazilian hospitals. The virulence profile has changed among these isolates since the ACME type I and II genes were also identified in this collection.}, } @article {pmid33375493, year = {2020}, author = {Pompilio, A and Ranalli, M and Piccirilli, A and Perilli, M and Vukovic, D and Savic, B and Krutova, M and Drevinek, P and Jonas, D and Fiscarelli, EV and Tuccio Guarna Assanti, V and Tavío, MM and Artiles, F and Di Bonaventura, G}, title = {Biofilm Formation among Stenotrophomonas maltophilia Isolates Has Clinical Relevance: The ANSELM Prospective Multicenter Study.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33375493}, issn = {2076-2607}, support = {grant number "FAR-2018" and "FAR-2019"//G. d'Annunzio University of Chieti-Pescara/ ; }, abstract = {The ability to form biofilms is a recognized trait of Stenotrophomonas maltophilia, but the extent of its clinical relevance is still unclear. The present multicenter prospective study (ANSELM) aims at investigating the association between biofilm formation and clinical outcomes of S. maltophilia infections. One hundred and nine isolates were collected from various geographical origins and stratified according to their clinical relevance. Biofilm formation was evaluated by the microtiter plate assay and correlated with microbiological and clinical data from the associated strains. Antibiotic susceptibility of the planktonic cells was tested by the disk diffusion technique, while antibiotic activity against mature biofilms was spectrophotometrically assessed. Most strains (91.7%) were able to form biofilm, although bloodborne strains produced biofilm amounts significantly higher than strains causing hospital- rather than community-acquired infections, and those recognized as "definite" pathogens. Biofilm formation efficiency was positively correlated with mechanical ventilation (p = 0.032), whereas a negative relationship was found with antibiotic resistance (r[2] = 0.107; p < 0.001), specifically in the case of the pathogenic strains. Mature S. maltophilia biofilms were markedly more resistant (up to 128 times) to cotrimoxazole and levofloxacin compared with their planktonic counterparts, especially in the case of bloodborne strains. Our findings indicate that biofilm formation by S. maltophilia is obviously a contributing factor in the pathogenesis of infections, especially in deep ones, thus warranting additional studies with larger cohort of patients and isolates.}, } @article {pmid33375417, year = {2020}, author = {Carbone, A and Cascioferro, S and Parrino, B and Carbone, D and Pecoraro, C and Schillaci, D and Cusimano, MG and Cirrincione, G and Diana, P}, title = {Thiazole Analogues of the Marine Alkaloid Nortopsentin as Inhibitors of Bacterial Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {26}, number = {1}, pages = {}, pmid = {33375417}, issn = {1420-3049}, support = {ARS01_00432//Italian Ministry of Education, University and Research/ ; }, mesh = {Alkaloids/chemistry/*pharmacology ; Aquatic Organisms/*chemistry ; Biofilms/drug effects/*growth & development ; Imidazoles/chemistry/*pharmacology ; Indoles/chemistry/*pharmacology ; Inhibitory Concentration 50 ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/*physiology ; Staphylococcus aureus/drug effects/*physiology ; Thiazoles/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Anti-virulence strategy is currently considered a promising approach to overcome the global threat of the antibiotic resistance. Among different bacterial virulence factors, the biofilm formation is recognized as one of the most relevant. Considering the high and growing percentage of multi-drug resistant infections that are biofilm-mediated, new therapeutic agents capable of counteracting the formation of biofilms are urgently required. In this scenario, a new series of 18 thiazole derivatives was efficiently synthesized and evaluated for its ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923 and S. aureus ATCC 6538 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. Most of the new compounds showed a marked selectivity against the Gram-positive strains. Remarkably, five compounds exhibited BIC50 values against S. aureus ATCC 25923 ranging from 1.0 to 9.1 µM. The new compounds, affecting the biofilm formation without any interference on microbial growth, can be considered promising lead compounds for the development of a new class of anti-virulence agents.}, } @article {pmid33374976, year = {2020}, author = {Rughöft, S and Jehmlich, N and Gutierrez, T and Kleindienst, S}, title = {Comparative Proteomics of Marinobacter sp. TT1 Reveals Corexit Impacts on Hydrocarbon Metabolism, Chemotactic Motility, and Biofilm Formation.}, journal = {Microorganisms}, volume = {9}, number = {1}, pages = {}, pmid = {33374976}, issn = {2076-2607}, support = {Elite Program for Postdocs//Baden-Württemberg Stiftung/ ; 326028733//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The application of chemical dispersants during marine oil spills can affect the community composition and activity of marine microorganisms. Several studies have indicated that certain marine hydrocarbon-degrading bacteria, such as Marinobacter spp., can be inhibited by chemical dispersants, resulting in lower abundances and/or reduced biodegradation rates. However, a major knowledge gap exists regarding the mechanisms underlying these physiological effects. Here, we performed comparative proteomics of the Deepwater Horizon isolate Marinobacter sp. TT1 grown under different conditions. Strain TT1 received different carbon sources (pyruvate vs. n-hexadecane) with and without added dispersant (Corexit EC9500A). Additional treatments contained crude oil in the form of a water-accommodated fraction (WAF) or chemically-enhanced WAF (CEWAF; with Corexit). For the first time, we identified the proteins associated with alkane metabolism and alginate biosynthesis in strain TT1, report on its potential for aromatic hydrocarbon biodegradation and present a protein-based proposed metabolism of Corexit components as carbon substrates. Our findings revealed that Corexit exposure affects hydrocarbon metabolism, chemotactic motility, biofilm formation, and induces solvent tolerance mechanisms, like efflux pumps, in strain TT1. This study provides novel insights into dispersant impacts on microbial hydrocarbon degraders that should be taken into consideration for future oil spill response actions.}, } @article {pmid33373862, year = {2021}, author = {Vendrell-Puigmitja, L and Llenas, L and Proia, L and Ponsa, S and Espinosa, C and Morin, S and Abril, M}, title = {Corrigendum to "Effects of an hypersaline effluent from an abandoned potash mine on freshwater biofilm and diatom communities" [Aquat. Toxicol. 230 (2020) 105707].}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {231}, number = {}, pages = {105724}, doi = {10.1016/j.aquatox.2020.105724}, pmid = {33373862}, issn = {1879-1514}, } @article {pmid33373326, year = {2021}, author = {Zhao, M and Zhang, F and Zarnowski, R and Barns, K and Jones, R and Fossen, J and Sanchez, H and Rajski, SR and Audhya, A and Bugni, TS and Andes, DR}, title = {Turbinmicin inhibits Candida biofilm growth by disrupting fungal vesicle-mediated trafficking.}, journal = {The Journal of clinical investigation}, volume = {131}, number = {5}, pages = {}, pmid = {33373326}, issn = {1558-8238}, support = {R35 GM134865/GM/NIGMS NIH HHS/United States ; U19 AI109673/AI/NIAID NIH HHS/United States ; U19 AI142720/AI/NIAID NIH HHS/United States ; R01 GM088151/GM/NIGMS NIH HHS/United States ; R01 GM110567/GM/NIGMS NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Benzopyrans/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*physiology ; Extracellular Vesicles/*metabolism ; Isoquinolines/*pharmacology ; }, abstract = {The emergence of drug-resistant fungi has prompted an urgent threat alert from the US Centers for Disease Control (CDC). Biofilm assembly by these pathogens further impairs effective therapy. We recently identified an antifungal, turbinmicin, that inhibits the fungal vesicle-mediated trafficking pathway and demonstrates broad-spectrum activity against planktonically growing fungi. During biofilm growth, vesicles with unique features play a critical role in the delivery of biofilm extracellular matrix components. As these components are largely responsible for the drug resistance associated with biofilm growth, we explored the utility of turbinmicin in the biofilm setting. We found that turbinmicin disrupted extracellular vesicle (EV) delivery during biofilm growth and that this impaired the subsequent assembly of the biofilm matrix. We demonstrated that elimination of the extracellular matrix rendered the drug-resistant biofilm communities susceptible to fungal killing by turbinmicin. Furthermore, the addition of turbinmicin to otherwise ineffective antifungal therapy potentiated the activity of these drugs. The underlying role of vesicles explains this dramatic activity and was supported by phenotype reversal with the addition of exogenous biofilm EVs. This striking capacity to cripple biofilm assembly mechanisms reveals a new approach to eradicating biofilms and sheds light on turbinmicin as a promising anti-biofilm drug.}, } @article {pmid33372380, year = {2021}, author = {Maestre-Reyna, M and Huang, WC and Wu, WJ and Singh, PK and Hartmann, R and Wang, PH and Lee, CC and Hikima, T and Yamamoto, M and Bessho, Y and Drescher, K and Tsai, MD and Wang, AH}, title = {Vibrio cholerae biofilm scaffolding protein RbmA shows an intrinsic, phosphate-dependent autoproteolysis activity.}, journal = {IUBMB life}, volume = {73}, number = {2}, pages = {418-431}, pmid = {33372380}, issn = {1521-6551}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects/growth & development ; Magnesium Compounds/*pharmacology ; Phosphates/*pharmacology ; *Proteolysis ; Vibrio cholerae/drug effects/growth & development/*metabolism ; }, abstract = {Vibrio cholerae is the causative agent of the diarrheal disease cholera, for which biofilm communities are considered to be environmental reservoirs. In endemic regions, and after algal blooms, which may result from phosphate enrichment following agricultural runoff, the bacterium is released from biofilms resulting in seasonal disease outbreaks. However, the molecular mechanism by which V. cholerae senses its environment and switches lifestyles from the biofilm-bound state to the planktonic state is largely unknown. Here, we report that the major biofilm scaffolding protein RbmA undergoes autocatalytic proteolysis via a phosphate-dependent induced proximity activation mechanism. Furthermore, we show that RbmA mutants that are defective in autoproteolysis cause V. cholerae biofilms to grow larger and mechanically stronger, correlating well with the observation that RbmA stability directly affects microbial community homeostasis and rheological properties. In conclusion, our biophysical study characterizes a novel phosphate-dependent breakdown pathway of RbmA, while microbiological data suggest a new, sensory role of this biofilm scaffolding element.}, } @article {pmid33372378, year = {2021}, author = {Ishikawa, KH and Bueno, MR and Kawamoto, D and Simionato, MRL and Mayer, MPA}, title = {Lactobacilli postbiotics reduce biofilm formation and alter transcription of virulence genes of Aggregatibacter actinomycetemcomitans.}, journal = {Molecular oral microbiology}, volume = {36}, number = {1}, pages = {92-102}, doi = {10.1111/omi.12330}, pmid = {33372378}, issn = {2041-1014}, mesh = {Aggregatibacter actinomycetemcomitans/genetics ; Biofilms ; Ecosystem ; *Lactobacillus/genetics ; *Probiotics ; Virulence ; }, abstract = {Periodontitis is characterized by a dysbiotic microbial community and treatment strategies include the reestablishment of symbiosis by reducing pathogens abundance. Aggregatibacter actinomycetemcomitans (Aa) is frequently associated with rapidly progressing periodontitis. Since the oral ecosystem may be affected by metabolic end-products of bacteria, we evaluated the effect of soluble compounds released by probiotic lactobacilli, known as postbiotics, on Aa biofilm and expression of virulence-associated genes. Cell-free pH-neutralized supernatants (CFS) of Lactobacillus rhamnosus Lr32, L. rhamnosus HN001, Lactobacillus acidophilus LA5, and L. acidophilus NCFM were tested against a fimbriated clinical isolate of Aa JP2 genotype (1 × 10[7] CFU/well) on biofilm formation for 24 hr, and early and mature preformed biofilms (2 and 24 hr). Lactobacilli CFS partially reduced Aa viable counts and biofilms biomass, but did not affect the number of viable non-adherent bacteria, except for LA5 CFS. Furthermore, LA5 CFS and, in a lesser extent HN001 CFS, influenced Aa preformed biofilms. Lactobacilli postbiotics altered expression profile of Aa in a strain-specific fashion. Transcription of cytolethal distending toxin (cdtB) and leukotoxin (ltxA) was downregulated by CFS of LA5 and LR32 CFS. Although all probiotics produced detectable peroxide, transcription of katA was downregulated by lactobacilli CFS. Transcription of dspB was abrogated by LR32 and NCFM CFS, but increased by HN001, whereas expression of pgA was not affected by any postbiotic. Our data indicated the potential of postbiotics from lactobacilli, especially LA5, to reduce colonization levels of Aa and to modulate the expression of virulence factors implicated in evasion of host defenses.}, } @article {pmid33371974, year = {2020}, author = {Latorre, MC and Alonso, B and Cruces, R and Sanz, A and Muñoz, P and Guembe, M}, title = {The classification of Staphylococcus aureus strains by biofilm production differs depending on the method used.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.eimc.2020.11.002}, pmid = {33371974}, issn = {2529-993X}, abstract = {INTRODUCTION: Strains can be classified in terms of biofilm production from quantitative absorbance values collectively by dividing strains into tertile ranks or individually by calculating the optical density for the negative control. However, these methods have not been compared in a large sample of Staphylococcus aureus strains. Therefore, our objective was to analyze the agreement between both methods in terms of biomass production and metabolic activity of their biofilm.

METHODS: We classified 233 S. aureus strains by biomass production and metabolic activity using the crystal violet and XTT assays, respectively. Strains were classified as low, moderate, or high biofilm producers according to tertile or optical density.

RESULTS: We found no agreement between both methods (p<0.001 and p=0.028, respectively).

CONCLUSIONS: We consider strains' biofilm classification by optical density to be a more reliable method, as it depends on the individual absorbance of each strain.}, } @article {pmid33371410, year = {2020}, author = {Lauková, A and Kandričáková, A and Bino, E}, title = {Susceptibility to Enterocins and Lantibiotic Bacteriocins of Biofilm-Forming Enterococci Isolated from Slovak Fermented Meat Products Available on the Market.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {24}, pages = {}, pmid = {33371410}, issn = {1660-4601}, mesh = {*Bacteriocins ; *Biofilms ; Bridged-Ring Compounds ; Enterococcus ; *Enterococcus faecium ; Meat Products/*microbiology ; Microbial Sensitivity Tests ; Slovakia ; }, abstract = {This study investigated eight types of Slovak dry fermented meat products (salami and sausages) that are available on the market and were produced by three different producers in different regions of Slovakia. The total counts of enterococci in these products ranged from 2.0 up to 6.0 cfu/g (log10). Three species were identified among the 15 selected enterococcal strains; Enterococcus faecium (8 strains), Enterococcus faecalis (3) and Enterococcus hirae (4). They were hemolysis-negative (γ-hemolysis) with a biofilm-forming ability, which was evaluated as low-grade biofilm formation, susceptible to conventional antibiotics and mainly susceptible to lantibiotic bacteriocins, namely, gallidermin and nisin; they even showed a higher susceptibility to gallidermin than to nisin. They were also susceptible to enterocin-durancin, but most strains showed resistance to enterocin A/P. This study indicated that bacteriocins can play a key role in preventing and/or protecting from undesirable bacterial multiplication or contamination in the food industry and that they have great potential for further experimental applications.}, } @article {pmid33371321, year = {2020}, author = {Yuan, X and Liu, J and Li, R and Zhou, J and Wei, J and Jiao, S and Wang, ZA and Du, Y}, title = {Chitosan Oligosaccharides Coupling Inhibits Bacterial Biofilm-Related Antibiotic Resistance against Florfenicol.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {24}, pages = {}, pmid = {33371321}, issn = {1420-3049}, support = {2017YFD0502300//National Key Research and Development Program of China/ ; 31670809//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Bacterial Infections/drug therapy ; Biofilms/*drug effects ; Chitosan/*chemistry ; Drug Resistance, Bacterial/*drug effects ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Microbial Sensitivity Tests ; Oligosaccharides/*chemistry/*pharmacology ; Plankton/drug effects ; Streptococcus/drug effects ; Thiamphenicol/analogs & derivatives/chemistry/pharmacology ; }, abstract = {The formation of bacterial biofilms has increased the resistance of bacteria to various environmental factors and is tightly associated with many persistent and chronic bacterial infections. Herein we design a strategy conjugating florfenicol, an antibiotic commonly used in the treatment of streptococcus, with the antimicrobial biomaterial, chitosan oligosaccharides. The results demonstrated that the florfenicol-COS conjugate (F-COS) efficiently eradicated the mature Streptococcus hyovaginalis biofilm, apparently inhibiting drug resistance to florfenicol. A quantity of 250 μg/mL F-COS showed effective inhibitory activity against planktonic cells and biofilm of the bacteria, and a 4-fold improvement of the F-COS compared to unmodified florfenicol was observed. Furthermore, the conjugate showed a broad-spectrum activity against both Gram-positive and Gram-negative bacteria. It suggested that F-COS might have a potential for application in the treatment of biofilm-related infections.}, } @article {pmid33370693, year = {2021}, author = {Shen, H and Durkin, DP and Aiello, A and Diba, T and Lafleur, J and Zara, JM and Shen, Y and Shuai, D}, title = {Photocatalytic graphitic carbon nitride-chitosan composites for pathogenic biofilm control under visible light irradiation.}, journal = {Journal of hazardous materials}, volume = {408}, number = {}, pages = {124890}, doi = {10.1016/j.jhazmat.2020.124890}, pmid = {33370693}, issn = {1873-3336}, mesh = {Biofilms ; Catalysis ; *Chitosan ; Graphite ; Light ; Nitrogen Compounds ; }, abstract = {Photocatalysis holds promise for inactivating environmental pathogens. Visible-light-responsive composites of carbon-doped graphitic carbon nitride and chitosan with high reactivity and processability were fabricated, and they can control pathogenic biofilms for environmental, food, biomedical, and building applications. The broad-spectrum biofilm inhibition and eradication of the photocatalytic composites against Staphylococcus epidermidis, Pseudomonas aeruginosa PAO1, and Escherichia coli O157: H7 under visible light irradiation were demonstrated. Extracellular polymeric substances in Escherichia coli O157: H7 biofilms were most resistant to photocatalytic oxidation, which led to reduced performance for biofilm removal. [1]O2 produced by the composites was believed to dominate biofilm inactivation. Moreover, the composites exhibited excellent performance for inhibiting biofilm development in urine, highlighting the promise for inactivating environmental biofilms developed from multiple bacterial species. Our study provides fundamental insights into the development of new photocatalytic composites, and elucidates the mechanism of how the photocatalyst reacts with a microbiological system.}, } @article {pmid33370414, year = {2020}, author = {Sandala, JL and Eichar, BW and Kuo, LG and Hahn, MM and Basak, AK and Huggins, WM and Woolard, K and Melander, C and Gunn, JS}, title = {A dual-therapy approach for the treatment of biofilm-mediated Salmonella gallbladder carriage.}, journal = {PLoS pathogens}, volume = {16}, number = {12}, pages = {e1009192}, pmid = {33370414}, issn = {1553-7374}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Asymptomatic Infections ; Biofilms/*drug effects ; Carrier State/*microbiology ; Gallbladder/*microbiology ; Mice ; *Salmonella Infections, Animal ; Salmonella typhi/*drug effects ; Typhoid Fever ; }, abstract = {Asymptomatic carriage of Salmonella Typhi continues to facilitate the transmission of typhoid fever, resulting in 14 million new infections and 136,000 fatalities each year. Asymptomatic chronic carriage of S. Typhi is facilitated by the formation of biofilms on gallstones that protect the bacteria from environmental insults and immune system clearance. Here, we identified two unique small molecules capable of both inhibiting Salmonella biofilm growth and disrupting pre-formed biofilm structures without affecting bacterial viability. In a mouse model of chronic gallbladder Salmonella carriage, treatment with either compound reduced bacterial burden in the gallbladder by 1-2 logs resulting in bacterial dissemination to peripheral organs that was associated with increased mortality. Co-administration of either compound with ciprofloxacin not only enhanced compound efficacy in the gallbladder by a further 1-1.5 logs for a total of 3-4.5 log reduction, but also prevented bacterial dissemination to peripheral organs. These data suggest a dual-therapy approach targeting both biofilm and planktonic populations can be further developed as a safe and efficient treatment of biofilm-mediated chronic S. Typhi infections.}, } @article {pmid33369598, year = {2020}, author = {Morris, AJ and Li, A and Jackson, L and Yau, YCW and Waters, V}, title = {Quantifying the Effects of Antimicrobials on In vitro Biofilm Architecture using COMSTAT Software.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {166}, pages = {}, doi = {10.3791/61759}, pmid = {33369598}, issn = {1940-087X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Fluorescence ; Humans ; Image Processing, Computer-Assisted ; Microscopy, Confocal ; Pseudomonas aeruginosa/drug effects/isolation & purification/physiology ; *Software ; }, abstract = {Biofilms are aggregates of microorganisms that rely on a self-produced matrix of extracellular polymeric substance for protection and structural integrity. The nosocomial pathogen, Pseudomonas aeruginosa, is known to adopt a biofilm mode of growth, causing chronic pulmonary infection in patients with cystic fibrosis (CF). The computer program, COMSTAT, is a useful tool for quantifying antimicrobial-induced changes in P. aeruginosa biofilm architecture by extracting data from three-dimensional confocal images. However, standardized operation of the software is less commonly addressed, which is important for optimal reporting of biofilm behavior and cross-center comparison. Thus, the aim of this protocol is to provide a simple and reproducible framework for quantifying in vitro biofilm structures under varying antimicrobial conditions via COMSTAT. The technique is modeled using a CF P. aeruginosa isolate, grown in the form of biofilm replicates, and exposed to tobramycin and the anti-Psl monoclonal antibody, Psl0096. The step-by-step approach aims to reduce user ambiguity and minimize the chance of overlooking crucial image-processing steps. Specifically, the protocol emphasizes the elimination of subjective variations associated with the manual operation of COMSTAT, including image segmentation and the selection of appropriate quantitative analysis functions. Although this method requires users to spend additional time processing confocal images prior to running COMSTAT, it helps minimize misrepresented biofilm heterogenicity in automated outputs.}, } @article {pmid33368278, year = {2021}, author = {Barreiros, P and Braga, J and Faria-Almeida, R and Coelho, C and Teughels, W and Souza, JCM}, title = {Remnant oral biofilm and microorganisms after autoclaving sterilization of retrieved healing abutments.}, journal = {Journal of periodontal research}, volume = {56}, number = {2}, pages = {415-422}, doi = {10.1111/jre.12834}, pmid = {33368278}, issn = {1600-0765}, support = {POCI-01-0145-FEDER-031035.//Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa/ ; }, mesh = {Biofilms ; *Dental Abutments ; *Dental Implants ; Humans ; Sterilization ; Surface Properties ; Titanium ; }, abstract = {OBJECTIVE: The purpose of this study was to evaluate the sterilization effectiveness against biofilms on retrieved healing abutments used in implant dentistry.

BACKGROUND: A large number of clinicians reuse healing abutments to decrease treatment costs although it can promote infection due to the presence of remnant biofilm biomass.

METHODS: One hundred and eighty-five titanium healing abutments previously used for 3 months in oral cavity were assessed in this study. Abutments were submitted to cleaning, chemical disinfection, and autoclave sterilization according to clinical guidelines. The abutments were aseptically placed into glass tubes containing specific bacterial growth medium and then incubated for 10 days. From glass tubes with bacterial growth, 100 µl medium was transferred to Schaedler's agar for morphological identification and counting of strict anaerobes and to Columbia blood agar for presumptive identification of facultative anaerobes after incubation. Isolated strains were then identified at species level by enzymatic and biochemical tests within API microorganism detection platform. Also, polymerase chain reaction (PCR) was performed for identification of undefined strains.

RESULTS: After the standard cleaning and sterilization procedures, fifty-six (approximately 30%) retrieved abutments showed the presence of remnant biofilm biomass. The bacteria identified into the remnant biofilms covering the abutments were representative of the commensal oral microbiota including Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Enterococcus faecalis.

CONCLUSION: Although some healing abutments did not reveal the existence of bacteria, organic components from biofilm biomass are still strongly adhered on the retentive micro-regions and surfaces of abutments and therefore that would support the accumulation of biofilm including pathogenic species leading to patients' cross-infections. Further studies should be performed on the assessment of different materials, design, and connections of the healing abutments associated with clinical disinfection procedures in implant dentistry.}, } @article {pmid33365069, year = {2021}, author = {Wu, S and Liu, Y and Lei, L and Zhang, H}, title = {Endogenous antisense walR RNA modulates biofilm organization and pathogenicity of Enterococcus faecalis.}, journal = {Experimental and therapeutic medicine}, volume = {21}, number = {1}, pages = {69}, pmid = {33365069}, issn = {1792-0981}, abstract = {Enterococcus faecalis (E. faecalis) is regarded as the major pathogen for persistent periapical periodontitis. The aim of the present study was to investigate the role of antisense walR RNA in the regulation of adjacent downstream genes. Reverse transcription-PCR assays were performed to validate walR. Adjacent downstream genes walK, EF1195, EF1196, and EF1197 were co-transcribed and detect antisense walR RNA. Northern blotting and 5'-rapid amplification of cDNA ends (5'-RACE) assays were conducted to detect and confirm a novel walR antisense (ASwalR) RNA. ASwalR overexpression mutants were constructed, and the biofilm biomass was determined using a crystal violet microtiter assay. The present study detected and confirmed a 550-bp noncoding antisense RNA with the potential to attenuate the activities of the essential response regulator WalR. The levels of antisense walR RNA transcripts were inversely associated with the production of WalR protein. It was showed that overexpression of ASwalR leads to reduced biofilm formation and exopolysaccharide synthesis. Furthermore, the pathogenicity of E. faecalis was markedly decreased by ASwalR overexpression in an in vivo periapical periodontitis model. In summary, the present study detected a novel antisense walR RNA that leads to a reduction in biofilm formation and the pathogenicity of E. faecalis. Collectively, the data suggest a role for ASwalR as a post-transcriptional modulator of the WalR regulator in E. faecalis.}, } @article {pmid33365021, year = {2020}, author = {Zhang, J and Meng, L and Zhang, Y and Sang, L and Liu, Q and Zhao, L and Liu, F and Wang, G}, title = {GapB Is Involved in Biofilm Formation Dependent on LrgAB but Not the SinI/R System in Bacillus cereus 0-9.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {591926}, pmid = {33365021}, issn = {1664-302X}, abstract = {Bacillus cereus 0-9, a Gram-positive endospore-forming bacterium isolated from healthy wheat roots, has biological control capacity against several soil-borne plant diseases of wheat such as sharp eyespot and take-all. The bacterium can produce various biofilms that differ in their architecture and formation mechanisms, possibly for adapting to different environments. The gapB gene, encoding a glyceraldehyde-3-phosphate dehydrogenase (GAPDH), plays a key role in B. cereus 0-9 biofilm formation. We studied the function of GapB and the mechanism of its involvement in regulating B. cereus 0-9 biofilm formation. GapB has GAPDH activities for both NAD[+]- and NADP[+]-dependent dehydrogenases and is a key enzyme in gluconeogenesis. Biofilm yield of the ΔgapB strain decreased by 78.5% compared with that of wild-type B. cereus 0-9 in lysogeny broth supplemented with some mineral salts (LBS), and the ΔgapB::gapB mutants were recovered with gapB gene supplementation. Interestingly, supplementing the LBS medium with 0.1-0.5% glycerol restored the biofilm formation capacity of the ΔgapB mutants. Therefore, GapB regulates biofilm formation relative to its function in gluconeogenesis. To illustrate how GapB is involved in regulating biofilm formation through gluconeogenesis, we carried out further research. The results indicate that the GapB regulated the B. cereus 0-9 biofilm formation independently of the exopolysaccharides and regulatory proteins in the typical SinI/R system, likely owing to the release of extracellular DNA in the matrix. Transcriptome analysis showed that the gapB deletion caused changes in the expression levels of only 18 genes, among which, lrgAB was the most significantly increased by 6.17-fold. We confirmed this hypothesis by counting the dead and living cells in the biofilms and found the number of living cells in the biofilm formed by the ΔgapB strain was nearly 7.5 times than that of wild-type B. cereus 0-9. Therefore, we concluded that the GapB is involved in the extracellular DNA release and biofilm formation by regulating the expression or activities of LrgAB. These results provide a new insight into the regulatory mechanism of bacterial biofilm formation and a new foundation for further studying the stress resistance of B. cereus.}, } @article {pmid33363047, year = {2020}, author = {Di Domenico, EG and Cavallo, I and Sivori, F and Marchesi, F and Prignano, G and Pimpinelli, F and Sperduti, I and Pelagalli, L and Di Salvo, F and Celesti, I and Paluzzi, S and Pronesti, C and Koudriavtseva, T and Ascenzioni, F and Toma, L and De Luca, A and Mengarelli, A and Ensoli, F}, title = {Biofilm Production by Carbapenem-Resistant Klebsiella pneumoniae Significantly Increases the Risk of Death in Oncological Patients.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {561741}, pmid = {33363047}, issn = {2235-2988}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Carbapenems/pharmacology ; Drug Resistance, Bacterial ; Humans ; *Klebsiella Infections/drug therapy/epidemiology ; *Klebsiella pneumoniae/genetics ; Middle Aged ; }, abstract = {Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a prominent cause of nosocomial infections associated with high rates of morbidity and mortality, particularly in oncological patients. The hypermucoviscous (HMV) phenotype and biofilm production are key factors for CRKP colonization and persistence in the host. This study aims at exploring the impact of CRKP virulence factors on morbidity and mortality in oncological patients. A total of 86 CRKP were collected between January 2015 and December 2019. Carbapenem resistance-associated genes, antibiotic susceptibility, the HMV phenotype, and biofilm production were evaluated. The median age of the patients was 71 years (range 40-96 years). Clinically infected patients were 53 (61.6%), while CRKP colonized individuals were 33 (38.4%). The most common infectious manifestations were sepsis (43.4%) and pneumonia (18.9%), while rectal surveillance swabs were the most common site of CRKP isolation (81.8%) in colonized patients. The leading mechanism of carbapenem resistance was sustained by the KPC gene (96.5%), followed by OXA-48 (2.3%) and VIM (1.2%). Phenotypic CRKP characterization indicated that 55.8% of the isolates were strong biofilm-producers equally distributed between infected (54.2%) and colonized (45.8%) patients. The HMV phenotype was found in 22.1% of the isolates, which showed a significant (P<0.0001) decrease in biofilm production as compared to non-HMV strains. The overall mortality rate calculated on the group of infected patients was 35.8%. In univariate analysis, pneumoniae significantly correlated with death (OR 5.09; CI 95% 1.08-24.02; P=0.04). The non-HMV phenotype (OR 4.67; CI 95% 1.13-19.24; P=0.03) and strong biofilm-producing strains (OR 5.04; CI95% 1.39-18.25; P=0.01) were also associated with increased CRKP infection-related mortality. Notably, the multivariate analysis showed that infection with strong biofilm-producing CRKP was an independent predictor of mortality (OR 6.30; CI 95% 1.392-18.248; P=0.004). CRKP infection presents a high risk of death among oncological patients, particularly when pneumoniae and sepsis are present. In infected patients, the presence of strong biofilm-producing CRKP significantly increases the risk of death. Thus, the assessment of biofilm production may provide a key element in supporting the clinical management of high-risk oncological patients with CRKP infection.}, } @article {pmid33360950, year = {2021}, author = {Deng, Y and Ruan, Y and Taherzadeh, MJ and Chen, J and Qi, W and Kong, D and Ma, B and Xu, X and Lu, H}, title = {Carbon availability shifts the nitrogen removal pathway and microbial community in biofilm airlift reactor.}, journal = {Bioresource technology}, volume = {323}, number = {}, pages = {124568}, doi = {10.1016/j.biortech.2020.124568}, pmid = {33360950}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Carbon ; Denitrification ; *Microbiota ; Nitrification ; *Nitrogen ; Wastewater ; }, abstract = {This study investigated the response of nitrogen removal performance and microbial community to different carbon composites in biofilm airlift reactors for wastewater treatment. Three reactors were filled with poly (butylene succinate) and bamboo powder composite at the blending ratio of 9:1, 1:1 and 1:9. Increasing the component of bamboo powder in the carrier reduced the carbon availability and had an adverse effect on nitrate removal efficiency. However, bamboo powder improved the ammonia removal rate which mainly through autotrophic nitrification. Three reactors exhibited distinct microbial compositions in both bacterial and fungal diversity. High inclusion of bamboo power decreased the relative abundance of denitrifiers Denitromonas and increased the relative abundance of nitrifiers, including Nitromonas, Nitrospina and Nitrospira. Moreover, correlation network revealed a competitive interaction between the taxa responsible for ammonia removal and nitrate removal processes. Those results indicated the feasibility of steering nitrogen removal pathway through carrier formulation in wastewater treatment.}, } @article {pmid33360720, year = {2021}, author = {Ren, J and Cheng, W and Jiao, M and Wan, T and Wang, M and Li, D}, title = {Characteristics of oxygen mass transfer and its impact on pollutant removal performance and microbial community structure in an aerobic fluidized bed biofilm reactor for treatment of municipal wastewater.}, journal = {Bioresource technology}, volume = {323}, number = {}, pages = {124552}, doi = {10.1016/j.biortech.2020.124552}, pmid = {33360720}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Environmental Pollutants ; *Microbiota ; Nitrification ; Nitrogen/analysis ; Oxygen ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {A laboratory-scale aerobic fluidized bed biofilm reactor (AFBBR) was established to evaluate the oxygen mass transfer (OMT) process and its impact on municipal wastewater treatment performance. Aeration rates had different effects on the OMT of the wastewater and biofilm. In the wastewater, oxygenation performance, oxygen uptake rate (OUR), and volumetric OMT coefficient (kLa) improved under high aeration rates. However, within the biofilm, the OMT process under the aeration rate of 0.096 L/(min·L) were higher than under other conditions [0.064 L/(min·L) and 0.128 L/(min·L)]. The denitrifying bacteria (DNB) abundance under the aeration rate of 0.096 L/(min·L) were improved so that total nitrogen (TN, 66.98 ± 4.23%) and ammonia nitrogen (NH4[+]-N, 74.70 ± 2.30%) removal were higher than those under other aeration conditions. These results showed that suitable aeration could improve wastewater treatment efficiency through changing the OMT process and microbial community structure.}, } @article {pmid33360301, year = {2021}, author = {Lee, SW and Phillips, KS and Gu, H and Kazemzadeh-Narbat, M and Ren, D}, title = {How microbes read the map: Effects of implant topography on bacterial adhesion and biofilm formation.}, journal = {Biomaterials}, volume = {268}, number = {}, pages = {120595}, doi = {10.1016/j.biomaterials.2020.120595}, pmid = {33360301}, issn = {1878-5905}, support = {R21 AI142424/AI/NIAID NIH HHS/United States ; }, mesh = {Bacteria ; *Bacterial Adhesion ; Biocompatible Materials ; *Biofilms ; Prostheses and Implants ; Surface Properties ; }, abstract = {Microbes have remarkable capabilities to attach to the surface of implanted medical devices and form biofilms that adversely impact device function and increase the risk of multidrug-resistant infections. The physicochemical properties of biomaterials have long been known to play an important role in biofilm formation. More recently, a series of discoveries in the natural world have stimulated great interest in the use of 3D surface topography to engineer antifouling materials that resist bacterial colonization. There is also increasing evidence that some medical device surface topographies, such as those designed for tissue integration, may unintentionally promote microbial attachment. Despite a number of reviews on surface topography and biofilm control, there is a missing link between how bacteria sense and respond to 3D surface topographies and the rational design of antifouling materials. Motivated by this gap, we present a review of how bacteria interact with surface topographies, and what can be learned from current laboratory studies of microbial adhesion and biofilm formation on specific topographic features and medical devices. We also address specific biocompatibility considerations and discuss how to improve the assessment of the anti-biofilm performance of topographic surfaces. We conclude that 3D surface topography, whether intended or unintended, is an important consideration in the rational design of safe medical devices. Future research on next-generation smart antifouling materials could benefit from a greater focus on translation to real-world applications.}, } @article {pmid33359358, year = {2021}, author = {Jabila Mary, TR and Kannan, RR and Iniyan, AM and Ramachandran, D and Prakash Vincent, SG}, title = {Cell wall distraction and biofilm inhibition of marine Streptomyces derived angucycline in methicillin resistant Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {150}, number = {}, pages = {104712}, doi = {10.1016/j.micpath.2020.104712}, pmid = {33359358}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Cell Wall ; India ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Staphylococcus aureus ; *Streptomyces/genetics ; Zebrafish ; }, abstract = {The emergence of life threatening antibiotic resistant pathogens and its associated mortality and morbidity necessitates many new antibiotics from diverse ecological habitats. Marine sponge associated microbes are promising to provide such antimicrobial compounds. In the present study, we report antibacterial and anti-biofilm potential of the angucycline antibiotic 8-O-metyltetrangomycin from Streptomyces sp. SBRK2 isolated from a marine sponge of Gulf of Mannar, Rameswaram, India. Our screening program to tackle methicillin-resistant Staphylococcus aureus (MRSA) drug resistance from marine sponge associated actinobacteria yielded the bioactive strain SBRK2. Based on 16S rRNA gene phylogenetic analysis the isolate was found to closely related with Streptomyces longispororuber NBRC 13488[T]. In vitro production by agar plate fermentation, solvent based extraction, TLC, HPLC purification and LC-MS based de-replication revealed the bioactive compound as 8-O-metyltetrangomycin. The antibacterial minimum inhibitory concentrations against MRSA was identified as 2 μg/mL. Sub-inhibitory concentration of the compound 8-O-metyltetrangomycin reduced the biofilm formation of S. aureus ATCC25923 and increased the cell surface hydrophobicity index. Scanning electron microscopic observation of the sub-inhibitory concentration exposure revealed a wrinkled membrane surface and slight cellular damage shows the cell wall distracting property of the compound. Zebrafish embryo based toxicity assays exhibited 100 μg/mL of compound as maximal non-lethal concentration which had demonstrated the positive relationship in safety index. The angucycline compound 8-O-metyltetrangomycin could be a potential candidate for the development of anti-biofilm agents against drug resistant pathogens.}, } @article {pmid33359276, year = {2021}, author = {Wang, Q and Zhang, X and Yang, Y}, title = {Effects of noise and harmonic excitation on the growth of Bacillus subtilis biofilm.}, journal = {Bio Systems}, volume = {201}, number = {}, pages = {104329}, doi = {10.1016/j.biosystems.2020.104329}, pmid = {33359276}, issn = {1872-8324}, mesh = {*Algorithms ; Bacillus subtilis/*physiology ; Biofilms/*growth & development ; *Computer Simulation ; Kinetics ; *Models, Biological ; Reproducibility of Results ; Stochastic Processes ; Stress, Physiological/physiology ; Time Factors ; }, abstract = {We study the dynamic growth behaviors of Bacillus subtilis biofilms by using a stochastic delay differential equation similar to the Mackey-Glass equation. We observe a wealth of dynamic behavior from a mathematical perspective. Firstly, the change of the time delay (i.e. the time that the growth state of the periphery to affect the stress of the interior cells needs and the time required for the stress signal coming from the interior to reach the peripheral cells) and the external excitation (i.e. the change in temperature) frequency will influence the size of Bacillus subtilis biofilm and the collective growth of the cell community. We also found the resonance phenomena in mathematics, which is of great help in understanding the behavior of stress levels in the biofilm periphery. Secondly, the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form theory and the center manifold reduction. Numerical simulations are carried out to ensure theoretical results. Finally, the effects of noise on stress levels in the biofilm periphery are analyzed and reveal more complex dynamics of the system.}, } @article {pmid33358877, year = {2021}, author = {Ahmad, JI and Dignum, M and Liu, G and Medema, G and van der Hoek, JP}, title = {Changes in biofilm composition and microbial water quality in drinking water distribution systems by temperature increase induced through thermal energy recovery.}, journal = {Environmental research}, volume = {194}, number = {}, pages = {110648}, doi = {10.1016/j.envres.2020.110648}, pmid = {33358877}, issn = {1096-0953}, mesh = {Biofilms ; *Drinking Water ; Temperature ; Water Microbiology ; Water Quality ; Water Supply ; }, abstract = {Drinking water distribution systems (DWDSs) have been thoroughly studied, but the concept of thermal energy recovery from DWDSs is very new and has been conceptualized in the past few years. Cold recovery results in a temperature increase of the drinking water. Its effects on drinking water quality and biofilm development are unclear. Hence, we studied both bulk water and biofilm phases for 232 days in two parallel pilot scale distribution systems with two temperature settings after cold recovery, 25 °C and 30 °C, and compared these with a reference pilot system without cold recovery. In all three pilot distributions systems (DSs) our results showed an initial increase in biomass (ATP) in the biofilm phase, along with occurrence of primary colonizers (Betaproteobacteriales) and subsequently a decrease in biomass and an increasing relative abundance of other microbial groups (amoeba resisting groups; Xanthobacteraceae, Legionellales), including those responsible for EPS formation in biofilms (Sphingomonadaceae). The timeline for biofilm microbial development was different for the three pilot DSs: the higher the temperature, the faster the development took place. With respect to the water phase within the three pilot DSs, major microbial contributions came from the feed water (17-100%) and unkown sources (2-80%). Random contributions of biofilm (0-70%) were seen between day 7-77. During this time period six-fold higher ATP concentration (7-11 ng/l) and two-fold higher numbers of high nucleic acid cells (5.20-5.80 × 10[4] cells/ml) were also observed in the effluent water from all three pilot DSs, compared to the feed water. At the end of the experimental period the microbial composition of effluent water from three pilot DSs revealed no differences, except the presence of a biofilm related microbial group (Sphingomonadaceae), within all three DSs compared to the feed water. In the biofilm phase higher temperatures initiated the growth of primary colonizing bacteria but this did not lead to differences in microbial diversity and composition at the end of the experimental period. Hence, we propose that the microbiological water quality of DWDSs with cold recovery should be monitored more frequently during the first 2-3 months of operation.}, } @article {pmid33358810, year = {2021}, author = {Pacha, PA and Munoz, MA and González-Rocha, G and San Martín, I and Quezada-Aguiluz, M and Aguayo-Reyes, A and Bello-Toledo, H and Latorre, AA}, title = {Molecular diversity of Staphylococcus aureus and the role of milking equipment adherences or biofilm as a source for bulk tank milk contamination.}, journal = {Journal of dairy science}, volume = {104}, number = {3}, pages = {3522-3531}, doi = {10.3168/jds.2020-19121}, pmid = {33358810}, issn = {1525-3198}, mesh = {Animals ; Biofilms ; Cattle ; *Cattle Diseases ; Chile ; Dairying ; Female ; *Mastitis, Bovine ; Milk ; *Staphylococcal Infections/veterinary ; Staphylococcus aureus/genetics ; }, abstract = {Staphylococcus aureus is one of the most frequent pathogens causing intramammary infections in dairy herds. Consequently, virulence factors, pathobiology, and epidemiology of Staphylococcus aureus strains have been widely assessed through the years. Nevertheless, not much has been described about the epidemiology of Staph. aureus strains from bulk tank milk (BTM) and adherences on milking equipment (AMES), even when these strains may play a role in the quality of milk that is intended for human consumption. The objective of this study was to assess the strain diversity of 166 Staph. aureus isolates collected from 3 consecutive BTM samples, and from AMES in contact with milk from 23 Chilean dairy farms. Isolates were analyzed and typed using pulsed-field gel electrophoresis. Diversity of strains, both within and among farms, was assessed using Simpson's index of diversity (SID). On farms where Staph. aureus was isolated from both AMES and BTM (n = 8), pulsotypes were further analyzed to evaluate the role of AMES as a potential source of Staph. aureus strains in BTM. Among all Staph. aureus analyzed by pulsed-field gel electrophoresis, a total of 42 pulsotypes (19 main pulsotypes and 23 subtypes) were identified. Among dairy farms, strain diversity was highly heterogeneous (SID = 0.99). Within dairy farms, Staph. aureus strain diversity was variable (SID = 0 to 1), and 18 dairy operations (81.8%) had one pulsotype that was shared between at least 2 successive BTM samples. In those farms where Staph. aureus was isolated in both AMES and BTM (n = 8), 7 (87.5%) showed a clonal distribution of Staph. aureus strains between these 2 types of samples. The overlapping of certain Staph. aureus strains among dairy farms may point out common sources of Staph. aureus among otherwise epidemiologically unrelated farms. Indistinguishable Staph. aureus strains between AMES and BTM across dairy farms suggest that Staph. aureus-containing AMES may represent a source for BTM contamination, thus affecting milk quality. Our study highlights the role of viable Staph. aureus in AMES as a source for BTM contamination on dairy farms, and also describes the overlapping and presence of specific BTM and AMES pulsotypes among farms.}, } @article {pmid33358443, year = {2021}, author = {Agarwalla, SV and Ellepola, K and Silikas, N and Castro Neto, AH and Seneviratne, CJ and Rosa, V}, title = {Persistent inhibition of Candida albicans biofilm and hyphae growth on titanium by graphene nanocoating.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {37}, number = {2}, pages = {370-377}, doi = {10.1016/j.dental.2020.11.028}, pmid = {33358443}, issn = {1879-0097}, mesh = {Biofilms ; *Candida albicans ; *Graphite ; Hyphae ; Surface Properties ; Titanium ; }, abstract = {OBJECTIVES: Candida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium.

METHODS: Graphene nanocoating was deposited twice (TiGD) or five times (TiGV) on grade 4 titanium with vacuum assisted technique and characterized with Raman spectroscopy and atomic force microscope. The biofilm formation and hyphae growth of C. albicans was monitored for seven days by CFU, XTT, confocal, mean cell density and scanning electronic microscopy (SEM). Uncoated titanium was the Control. All tests had three independent biological samples and were performed in independent triplicates. Data was analyzed with one- or two-way ANOVA and Tukey's HSD (α = 0.05).

RESULTS: Both TiGD and TiGV presented less biofilms at all times points compared with Control. The confocal and SEM images revealed few adhered cells on graphene coated samples, absence of hyphae and no features of a mature biofilm architecture. The increase in number of layers of graphene nanocoating did not improve its antibiofilm potential.

SIGNIFICANCE: The graphene nanocoating exerted a long-term persistent inhibitory effect on the biofilm formation on titanium. The fewer cells that were able to attach on graphene coated titanium were scattered and unable to form a mature biofilm with hyphae elements. The findings open opportunities to prevent microbial attachment and proliferation on implantable materials without the use of antibiotics.}, } @article {pmid33358017, year = {2021}, author = {Hui, WL and Ipe, D and Perrotti, V and Piattelli, A and Fang, Z and Ostrikov, K and Quaranta, A}, title = {Novel technique using cold atmospheric plasma coupled with air-polishing for the treatment of titanium discs grown with biofilm: An in-vitro study.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {37}, number = {2}, pages = {359-369}, doi = {10.1016/j.dental.2020.11.027}, pmid = {33358017}, issn = {1879-0097}, mesh = {Air Abrasion, Dental ; Biofilms ; *Dental Implants ; Humans ; Microscopy, Electron, Scanning ; Plasma ; *Plasma Gases ; Surface Properties ; Titanium ; }, abstract = {OBJECTIVES: The aim of the present study was to assess the decontamination efficacy and titanium surface alterations of erythritol based air abrasion (AA) and cold atmospheric plasma (CAP) targeting a human complex biofilm.

METHODS: Saliva collected from a peri-implantitis patient was used to develop in vitro human biofilm over titanium discs with machined (group A) and moderately rough (group B) surface. The discs were treated with AA, experimental CAP or a combination of both treatments (COM). The amount of biofilm on the discs was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by SEM and laser profilometry, respectively. The data were statistically analyzed using Kruskal Wallis followed by Dunn's multiple comparison test after being checked for normality by Shapiro-Wilk test.

RESULTS: All the discs in group A performed better to treatments compared to group B. In both groups, CV data showed significantly lower amount of biofilm after AA treatment compared to CAP (p<0.05). Cleaning efficacy revealed relevant decontamination of both the surfaces following AA and COM treatments and almost complete biofilm removal after AA application on group A (99.92%). SEM analysis demonstrated no post-treatment alterations on the discs and laser profilometry did not show statistically significant changes in Sa and Sdr values.

SIGNIFICANCE: Decontamination with AA delivering erythritol with or without CAP is highly effective in biofilm removal from different titanium surfaces. All the tested treatments, including CAP showed no noticeable alterations of the titanium discs surface features. Further in vivo studies are necessary to understand the potential of CAP technology in implant surface decontamination.}, } @article {pmid33357978, year = {2020}, author = {Chotinantakul, K and Chansiw, N and Okada, S}, title = {Erratum to "Biofilm formation and transfer of a streptomycin resistance gene in enterococci from fermented pork" [J Glob Antimicrob Resist 22 (2020) 434-440].}, journal = {Journal of global antimicrobial resistance}, volume = {23}, number = {}, pages = {473}, doi = {10.1016/j.jgar.2020.10.001}, pmid = {33357978}, issn = {2213-7173}, } @article {pmid33356046, year = {2020}, author = {Chen, X and Zheng, L and Chen, DK}, title = {[Inhibitory effect of Ningmitai Capsules on the proliferation and biofilm formation of Staphylococcus sp. and Escherichia coli].}, journal = {Zhonghua nan ke xue = National journal of andrology}, volume = {26}, number = {6}, pages = {553-558}, pmid = {33356046}, issn = {1009-3591}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Capsules ; Cholinergic Agents/*pharmacology ; Escherichia coli/*drug effects ; Staphylococcus/*drug effects ; }, abstract = {OBJECTIVE: To evaluate the inhibitory effect of Ningmitai Capsules (NMTC) on the proliferation and in vitro biofilm formation of Staphylococcus sp. and Escherichia coli (E. coli).

METHODS: Using the gradient dilution method, we determined the minimum inhibitory concentration (MIC) of NMTC against Staphylococcus epidermidis (S. epidermids) 1457, Staphylococcus aureus (S. aureus) NCTC8325-4/ Newman/ MU50 and E. coli ATCC25922/ CF073, and observed the effects of different concentrations of NMTC on their biofilm formation in vitro under the electron microscope.

RESULTS: NMTC significantly suppressed the proliferation of S. epidermidis 1457, S. aureus NCTC8325-4/ Newman/ MU50 and E. coli ATCC25922/CF073 at an MIC of 20 mg/ml as well as their biofilm formation in vitro.

CONCLUSIONS: Ningmitai Capsules can inhibit the proliferation and in vitro biofilm formation of S. epidermids and E. coli, and has a comprehensive antibacterial effect.}, } @article {pmid33353409, year = {2020}, author = {Seethalakshmi, PS and Rajeev, R and Kiran, GS and Selvin, J}, title = {Promising treatment strategies to combat Staphylococcus aureus biofilm infections: an updated review.}, journal = {Biofouling}, volume = {36}, number = {10}, pages = {1159-1181}, doi = {10.1080/08927014.2020.1857743}, pmid = {33353409}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Humans ; Microbial Sensitivity Tests ; Staphylococcal Infections/drug therapy ; *Staphylococcus aureus ; }, abstract = {Staphylococcus aureus is a leading cause of nosocomial and community-acquired infections. The formation of biofilm by this pathogen renders it resilient to antimicrobial agents, which complicates the treatment of such infections. S. aureus can form biofilms with other pathogens and cause polymicrobial infections recalcitrant to antimicrobial agents. Therefore, anti-biofilm agents against which this bacterium cannot develop resistance are a highly desirable treatment strategy. Nanoparticles and some non-antimicrobial drugs proposed for various clinical purposes have proven to be excellent antibacterial and anti-biofilm agents to control S. aureus biofilm infections. A variety of chemically distinct compounds capable of acting as anti-biofilm agents against S. aureus have been extracted from microbial sources. This review explains the characteristics of S. aureus biofilms, emphasizing the therapeutic potential of nanoparticles, repurposed drugs, and anti-biofilm agents from microbial sources to combat S. aureus biofilm infections.}, } @article {pmid33353223, year = {2020}, author = {Krzyżek, P and Grande, R and Migdał, P and Paluch, E and Gościniak, G}, title = {Biofilm Formation as a Complex Result of Virulence and Adaptive Responses of Helicobacter pylori.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33353223}, issn = {2076-0817}, support = {STM.A130.20.002//Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu/ ; 016/RID/2018/19//Ministry of Science and Higher Education in the "Regional Initiative of Excellence" programme/ ; }, abstract = {Helicobacter pylori is a bacterium that is capable of colonizing a host for many years, often for a lifetime. The survival in the gastric environment is enabled by the production of numerous virulence factors conditioning adhesion to the mucosa surface, acquisition of nutrients, and neutralization of the immune system activity. It is increasingly recognized, however, that the adaptive mechanisms of H. pylori in the stomach may also be linked to the ability of this pathogen to form biofilms. Initially, biofilms produced by H. pylori were strongly associated by scientists with water distribution systems and considered as a survival mechanism outside the host and a source of fecal-oral infections. In the course of the last 20 years, however, this trend has changed and now the most attention is focused on the biomedical aspect of this structure and its potential contribution to the therapeutic difficulties of H. pylori. Taking into account this fact, the aim of the current review is to discuss the phenomenon of H. pylori biofilm formation and present this mechanism as a resultant of the virulence and adaptive responses of H. pylori, including morphological transformation, membrane vesicles secretion, matrix production, efflux pump activity, and intermicrobial communication. These mechanisms will be considered in the context of transcriptomic and proteomic changes in H. pylori biofilms and their modulating effect on the development of this complex structure.}, } @article {pmid33352977, year = {2020}, author = {Rebaza, TD and Ludeña, Y and Samolski, I and Villena, GK}, title = {Gene Expression Analysis of Non-Clinical Strain of Aspergillus fumigatus (LMB-35Aa): Does Biofilm Affect Virulence?.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {33352977}, issn = {2309-608X}, support = {N° 181-2015-FONDECYT-DE//Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica de Perú/ ; N° 177-2015-CONCYTEC-FONDECYT-DE//Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica de Perú/ ; }, abstract = {Aspergillus fumigatus LMB-35Aa, a saprophytic fungus, was used for cellulase production through biofilms cultures. Since biofilms usually favor virulence in clinical strains, the expression of the related genes of the LMB 35-Aa strain was analyzed by qPCR from the biomass of planktonic cultures and biofilms developed on polyester cloth and polystyrene microplates. For this, virulence-related genes reported for the clinical strain Af293 were searched in A. fumigatus LMB 35-Aa genome, and 15 genes were identified including those for the synthesis of cell wall components, hydrophobins, invasins, efflux transporters, mycotoxins and regulators. When compared with planktonic cultures at 37 °C, invasin gene calA was upregulated in both types of biofilm and efflux transporter genes mdr4 and atrF were predominantly upregulated in biofilms on polystyrene, while aspHs and ftmA were upregulated only in biofilms formed on polyester. Regarding the transcription regulators, laeA was downregulated in biofilms, and medA did not show a significant change. The effect of temperature was also evaluated by comparing the biofilms grown on polyester at 37 vs. 28 °C. Non-significant changes at the expression level were found for most genes evaluated, except for atrF, gliZ and medA, which were significantly downregulated at 37 °C. According to these results, virulence appears to depend on the interaction of several factors in addition to biofilms and growth temperature.}, } @article {pmid33352641, year = {2020}, author = {Olivares, E and Tasse, J and Badel-Berchoux, S and Provot, C and Prévost, G and Bernardi, T}, title = {Clinical Biofilm Ring Test[®] Reveals the Potential Role of β-Lactams in the Induction of Biofilm Formation by P. aeruginosa in Cystic Fibrosis Patients.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33352641}, issn = {2076-0817}, abstract = {Biofilms are characterized by high tolerance to antimicrobials. However, conventional antibiograms are performed on planktonic microorganisms. Through the clinical Biofilm Ring Test[®] (cBRT), initially aimed to measure the adhesion propensity of bacteria, we discerned a variable distribution of biofilm-producer strains among P. aeruginosa samples isolated from expectorations of cystic fibrosis (CF) patients. Despite a majority of spontaneous adherent isolates, few strains remained planktonic after 5 h of incubation. Their analysis by an adapted protocol of the cBRT revealed an induction of the biofilm early formation by sub-inhibitory doses of β-lactams. Microscopic observations of bacterial cultures stained with Syto 9/Propidium Iodide (PI) confirmed the ability of antimicrobials to increase either the bacterial biomass or the biovolume occupied by induced sessile cells. Finally, the cBRT and its derivatives enabled to highlight in a few hours the potential inducer property of antibiotics on bacterial adhesion. This phenomenon should be considered carefully in the context of CF since patients are constantly under fluctuating antimicrobial treatments. To conclude, assays derived from the Biofilm Ring Test[®] (BRT) device, not only define efficient doses preventing biofilm formation, but could be useful for the antimicrobial selection in CF, to avoid inducer molecules of the early biofilm initiation.}, } @article {pmid33352215, year = {2021}, author = {Rashiya, N and Padmini, N and Ajilda, AAK and Prabakaran, P and Durgadevi, R and Veera Ravi, A and Ghosh, S and Sivakumar, N and Selvakumar, G}, title = {Inhibition of biofilm formation and quorum sensing mediated virulence in Pseudomonas aeruginosa by marine sponge symbiont Brevibacterium casei strain Alu 1.}, journal = {Microbial pathogenesis}, volume = {150}, number = {}, pages = {104693}, doi = {10.1016/j.micpath.2020.104693}, pmid = {33352215}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Brevibacterium ; Chromobacterium ; *Porifera ; Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence ; }, abstract = {The alternative antimicrobial strategies that mitigate the threat of antibiotic resistance is the quorum-sensing inhibition (QSI) mechanism, which targets autoinducer dependent virulence gene expression in bacterial pathogens. N-acyl homoserine lactone (AHL) acts as a key regulator in the production of virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1 and violacein pigment production in Chromobacterium violaceum ATCC 12472. In the present study, the marine sponge Haliclona fibulata symbiont Brevibacterium casei strain Alu 1 showed potential QSI activity in a concentration-dependent manner (0.5-2% v/v) against the N-acyl homoserine lactone (AHL)-mediated violacein production in C. violaceum (75-95%), and biofilm formation (53-96%), protease (27-82%), pyocyanin (82-95%) and pyoverdin (29-38%) productions in P. aeruginosa. Further, the microscopic analyses validated the antibiofilm activity of the cell-free culture supernatant (CFCS) of B. casei against P. aeruginosa. Subsequently, the biofilm and pyoverdin inhibitory efficacy of the ethyl acetate extract of B. casei CFCS was assessed against P. aeruginosa. Further, the gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of variety of components in which diethyl phthalate was found to be a major active component. This phthalate ester, known as diethyl ester of phthalic acid, could act as a potential therapeutic agent for preventing bacterial biofilm and virulence associated infectious diseases.}, } @article {pmid33351859, year = {2020}, author = {Donnert, M and Elsheikh, S and Arce-Rodriguez, A and Pawar, V and Braubach, P and Jonigk, D and Haverich, A and Weiss, S and Müsken, M and Häussler, S}, title = {Targeting bioenergetics is key to counteracting the drug-tolerant state of biofilm-grown bacteria.}, journal = {PLoS pathogens}, volume = {16}, number = {12}, pages = {e1009126}, pmid = {33351859}, issn = {1553-7374}, mesh = {Animals ; Biofilms/*drug effects ; Drug Tolerance/physiology ; Energy Metabolism/*drug effects ; Humans ; Mice ; Mice, Inbred BALB C ; Promethazine/*pharmacology ; Pseudomonas Infections ; Pseudomonas aeruginosa/*drug effects/*physiology ; }, abstract = {Embedded in an extracellular matrix, biofilm-residing bacteria are protected from diverse physicochemical insults. In accordance, in the human host the general recalcitrance of biofilm-grown bacteria hinders successful eradication of chronic, biofilm-associated infections. In this study, we demonstrate that upon addition of promethazine, an FDA approved drug, antibiotic tolerance of in vitro biofilm-grown bacteria can be abolished. We show that following the addition of promethazine, diverse antibiotics are capable of efficiently killing biofilm-residing cells at minimal inhibitory concentrations. Synergistic effects could also be observed in a murine in vivo model system. PMZ was shown to increase membrane potential and interfere with bacterial respiration. Of note, antibiotic killing activity was elevated when PMZ was added to cells grown under environmental conditions that induce low intracellular proton levels. Our results imply that biofilm-grown bacteria avoid antibiotic killing and become tolerant by counteracting intracellular alkalization through the adaptation of metabolic and transport functions. Abrogation of antibiotic tolerance by interfering with the cell's bioenergetics promises to pave the way for successful eradication of biofilm-associated infections. Repurposing promethazine as a biofilm-sensitizing drug has the potential to accelerate the introduction of new treatments for recalcitrant, biofilm-associated infections into the clinic.}, } @article {pmid33350564, year = {2021}, author = {Mahajan, S and Ramya, TNC}, title = {Cellulophaga algicola alginate lyase inhibits biofilm formation of a clinical Pseudomonas aeruginosa strain MCC 2081.}, journal = {IUBMB life}, volume = {73}, number = {2}, pages = {444-462}, doi = {10.1002/iub.2442}, pmid = {33350564}, issn = {1521-6551}, mesh = {A549 Cells ; Anti-Bacterial Agents/*administration & dosage ; Bacterial Proteins/*administration & dosage ; Biofilms/*drug effects/growth & development ; Flavobacteriaceae/*enzymology ; Humans ; Polysaccharide-Lyases/*administration & dosage/metabolism ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification ; }, abstract = {Alginate lyases are potential agents for disrupting alginate-rich Pseudomonas biofilms in the infected lungs of cystic fibrosis patients but there is as yet no clinically approved alginate lyase that can be used as a therapeutic. We report here the endolytic alginate lyase activity of a recombinant Cellulophaga algicola alginate lyase domain (CaAly) encoded by a gene that also codes for an N-terminal carbohydrate-binding module, CBM6, and a central F-type lectin domain (CaFLD). CaAly degraded both polyM and polyG alginates with optimal temperature and pH of 37°C and pH 7, respectively, with greater preference for polyG. Recombinant CaFLD bound to fucosylated glycans with a preference for H-type 2 glycan motif, and did not have any apparent effect on the enzyme activity of the co-associated alginate lyase domain in the recombinant protein construct, CaFLD_Aly. We assessed the potential of CaAly and other alginate lyases previously reported in published literature to inhibit biofilm formation by a clinical strain, Pseudomonas aeruginosa MCC 2081. Of all the alginate lyases tested, CaAly displayed most inhibition of in vitro biofilm formation on plastic surfaces. We also assessed its inhibitory ability against P. aeruginosa 2081 biofilms formed over a monolayer of A549 lung epithelial cells. Our study indicated that CaAly is efficacious in inhibition of biofilm formation even on A549 lung epithelial cell line monolayers.}, } @article {pmid33349045, year = {2020}, author = {Florez Salamanca, EJ and Dantas, RM and Rodriguez, MJ and Klein, MI}, title = {Establishment of microcosm biofilm models that reproduce a cariogenic diet intake.}, journal = {Biofouling}, volume = {36}, number = {10}, pages = {1196-1209}, doi = {10.1080/08927014.2020.1862093}, pmid = {33349045}, issn = {1029-2454}, mesh = {Animals ; *Biofilms ; Cattle ; Dental Caries/etiology ; *Diet, Cariogenic ; Humans ; Hydrogen-Ion Concentration ; Streptococcus mutans ; Tooth Demineralization/etiology ; }, abstract = {Biofilms were developed from human saliva on bovine enamel discs in four experimental conditions to investigate dental caries development: feast and famine (M1), abundance and scarcity (M2), three meals daily (M3), and three meals plus two snacks daily (M4). The main difference between these models was the diet for microbial growth. The evaluations included verifying the pH of the spent culture media and analyzing the enamel discs for demineralization (microhardness and roughness) and biofilms (biomass, viable populations of mutans streptococci, and total microbiota). Two major behaviors were observed: M1 and M2 promoted an acidic environment, while M3 and M4 maintained pH values closer to neutral. The demineralization process was slower in the neutral groups but more pronounced in M3, while a greater increase in microbiota and biomass was observed over time for both neutral groups. Thus, the M3 model was better at mimicking the oral environment that leads to demineralization.}, } @article {pmid33349036, year = {2020}, author = {Naksagoon, T and Ohsumi, T and Takenaka, S and Nagata, R and Hasegawa, T and Maeda, T and Noiri, Y}, title = {Effect of water aging on the anti-biofilm properties of glass ionomer cement containing fluoro-zinc-silicate fillers.}, journal = {Biofouling}, volume = {36}, number = {9}, pages = {1090-1099}, doi = {10.1080/08927014.2020.1856371}, pmid = {33349036}, issn = {1029-2454}, mesh = {*Biofilms ; Fluorides/pharmacology ; Glass Ionomer Cements/pharmacology ; Silicates ; Streptococcus mutans ; Water ; Zinc/pharmacology ; }, abstract = {A previous study has reported that a novel fluoro-zinc-silicate glass ionomer cement (Caredyne Restore) showed superior anti-biofilm effects by interfering with bacterial adhesion. However, the active ions may degrade with time. This study aimed to assess the valid anti-biofilm effects of Caredyne Restore after being aged by water immersion for 3 weeks. Streptococcus mutans biofilm was allowed to grow on the surface before and after water aging for 24 h using a modified Robbins device flow-cell system. The results showed water aging promoted biofilm formation. Insufficient amount of fluoride and zinc ions were released from Caredyne Restore after water aging under neutral pH condition. An acidic pH is needed to exert effective anti-biofilm properties. As the release of active ions from Caredyne Restore will gradually decrease after the restoration, the restoration may not prevent biofilm formation after 3 weeks while neutral pH is maintained by the buffering capacity of saliva.}, } @article {pmid33348848, year = {2020}, author = {Li, T and Wang, Z and Han, H and Teng, D and Mao, R and Hao, Y and Yang, N and Wang, X and Wang, J}, title = {Dual Antibacterial Activities and Biofilm Eradication of a Marine Peptide-N6NH2 and Its Analogs against Multidrug-Resistant Aeromonas veronii.}, journal = {International journal of molecular sciences}, volume = {21}, number = {24}, pages = {}, pmid = {33348848}, issn = {1422-0067}, support = {31772640//National Natural Science Foundation of China/ ; 31572444//National Natural Science Foundation of China/ ; 31572445//National Natural Science Foundation of China/ ; CAAS-ZDXT2018008//Key Project of Alternatives to Antibiotic for Feed Usages from Chinese Academy of Agricultural Sciences/ ; }, mesh = {Aeromonas veronii/*drug effects/growth & development ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Drug Resistance, Multiple/*drug effects ; Female ; Gram-Negative Bacterial Infections/complications/*drug therapy/microbiology ; Mice ; Mice, Inbred ICR ; Microbial Sensitivity Tests ; Multiple Organ Failure/complications/*drug therapy/microbiology ; Skin Ulcer/complications/*drug therapy/microbiology ; }, abstract = {Aeromonas veronii is one of the main pathogens causing various diseases in humans and animals. It is currently difficult to eradicate drug-resistant A. veronii due to the biofilm formation by conventional antibiotic treatments. In this study, a marine peptide-N6NH2 and its analogs were generated by introducing Orn or replacing with D-amino acids, Val and Pro; their enzymic stability and antibacterial/antibiofilm ability against multi-drug resistant (MDR) A. veronii ACCC61732 were detected in vitro and in vivo, respectively. The results showed that DN6NH2 more rapidly killed A. veronii ACCC61732 and had higher stability in trypsin, simulated gastric/intestinal fluid, proteinase K, and mouse serum than the parent peptide-N6NH2. DN6NH2 and other analogs significantly improved the ability of N6NH2 to penetrate the outer membrane of A. veronii ACCC61732. DN6NH2, N6PNH2 and V112N6NH2 protected mice from catheter-associated biofilm infection with MDR A. veronii ACCC61732, superior to N6NH2 and CIP. DN6NH2 had more potent efficacy at a dose of 5 μmol/kg (100% survival) in a mouse peritonitis model than other analogs (50-66.67%) and CIP (83.33%), and it inhibited the bacterial translocation, downregulated pro-inflammatory cytokines, upregulated the anti-inflammatory cytokine, and ameliorated multiple-organ injuries (including the liver, spleen, lung, and kidney). These data suggest that the analogs of N6NH2 may be a candidate for novel antimicrobial and antibiofilm agents against MDR A. veronii infections.}, } @article {pmid33345900, year = {2021}, author = {Wang, J and Ying, X and Huang, Y and Chen, Y and Shen, D and Zhang, X and Feng, HJ}, title = {Numerical study of hydrodynamic characteristics in a moving bed biofilm reactor.}, journal = {Environmental research}, volume = {194}, number = {}, pages = {110614}, doi = {10.1016/j.envres.2020.110614}, pmid = {33345900}, issn = {1096-0953}, mesh = {*Biofilms ; Bioreactors ; Hydrodynamics ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {The moving bed biofilm reactor (MBBR) has certain advantages, such as high wastewater treatment efficiency, low maintenance and operating costs, and simple operation. It has emerged as a valuable option for small decentralized facilities. The filling ratio, aeration mode and aeration intensity are the main factors that affect the performance of MBBRs in wastewater treatment. However, the information that concerns the used criteria that pertain to the process design for the MBBR is not adequate. In this study, a three dimensional computational fluid dynamics (CFD) model was constructed and the maximum error was only 1.98%, which was much smaller than the traditional 2D-CFD model. The filling ratio, aeration mode and aeration intensity of MBBR were optimized by CFD model from the point of view of fluid mechanics. The results show that the fluidization performance of the filling is the best under the one-side aeration mode with 30% filling ratio. The cost-performance ratio of the reactor with 30% filling ratio was 1.53, 25% and 35% filling ratio were only 1.17 and 1.14 respectively. Increasing the aeration intensity could improve the fluidization performance. However, the effect of high aeration intensity on the fluidization performance of the carrier was limited and the energy consumption increased greatly. The results revealed that when the aeration intensity increased from 0.07 min[-1] to 0.13 min[-1], the proportion of the carrier area increased by 16.56%. The proportion of the carrier area with an aeration rate of 0.20 min[-1] was only 4.23%, which is higher than 0.13 min[-1]. The main factors that control the fluidization of the carrier were the range of the flow zone and the flow velocity of the liquid. Increasing the range of the flow zone could facilitate the flow of the carriers. The critical value of the flow velocity of the liquid in the flow zone was 0.04 m/s. These results could guide the optimization design of the filling ratio and the aeration conditions and provide a theoretical basis for the application of MBBR.}, } @article {pmid33344433, year = {2020}, author = {Nobre, CMG and Pütz, N and König, B and Rupf, S and Hannig, M}, title = {Modification of in situ Biofilm Formation on Titanium by a Hydroxyapatite Nanoparticle-Based Solution.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {598311}, pmid = {33344433}, issn = {2296-4185}, abstract = {Oral biofilms play an essential role on peri-implant disease development. Synthetic hydroxyapatite nanoparticles (nHAP) are a bioinspired material that has structural and functional similarities to dental enamel apatite and may provide preventive properties against biofilm formation. This study aimed to investigate the effects of an experimental nHAP solution on biofilm formation on polished and non-polished titanium under oral conditions. Five volunteers carried maxillary splints with non-polished and polished titanium and followed a 48 h rinsing protocol with the proposed nHAP solution, and with chlorhexidine 0.2% (CHX) and water, as controls. Samples were analyzed by fluorescence microscopy (FM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). FM showed a significant reduction of biofilms on polished samples treated with nHAP (p = 0.0485) compared with water, without differences between nHAP and CHX (p > 0.9999). Analyzing biofilm viability, polished samples rinsed with nHAP showed significantly fewer dead bacteria than CHX (p = 0.0079), but there was no significant difference in viability between polished samples rinsed with water and nHAP (p = 0.9268). A significantly higher biofilm coverage was observed on the non-polished surfaces compared to the polished surfaces when nHAP was applied (p = 0.0317). This difference between polished and non-polished surfaces was not significant when water (p = 0.1587) or CHX (p = 0.3413) rinsing were applied. SEM and TEM analysis supported the FM findings, that polished samples rinsed with nHAP presented fewer biofilm coverage compared to samples rinsed with water. In conclusion, the nHAP solution reduced the biofilm formation on polished Ti surfaces without altering bacterial viability, providing a novel approach for the management of biofilm formation on biomaterials.}, } @article {pmid33344087, year = {2020}, author = {Tewawong, N and Kowaboot, S and Pimainog, Y and Watanagul, N and Thongmee, T and Poovorawan, Y}, title = {Distribution of phylogenetic groups, adhesin genes, biofilm formation, and antimicrobial resistance of uropathogenic Escherichia coli isolated from hospitalized patients in Thailand.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e10453}, pmid = {33344087}, issn = {2167-8359}, abstract = {BACKGROUND: Urinary tract infections (UTIs) are the most common bacterial infections and are often caused by uropathogenic Escherichia coli (UPEC). We investigated the distribution of phylogenetic groups, adhesin genes, antimicrobial resistance, and biofilm formation in E. coli isolated from patients with UTIs.

METHODS: In the present study, 208 UPEC isolated from Thai patients were classified into phylogenetic groups and adhesin genes were detected using multiplex PCR. Antimicrobial susceptibility testing was performed using agar disk diffusion. The Congo red agar method was used to determine the ability of the UPEC to form biofilm.

RESULTS: The most prevalent UPEC strains in this study belonged to phylogenetic group B2 (58.7%), followed by group C (12.5%), group E (12.0%), and the other groups (16.8%). Among adhesin genes, the prevalence of fimH (91.8%) was highest, followed by pap (79.3%), sfa (12.0%), and afa (7.7%). The rates of resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, and amoxicillin-clavulanate were  65%, 54.3%, and 36.5%, respectively. The presence of adhesin genes and antibiotic resistance were more frequent in groups B2 and C compared to the other groups. Of the 129 multidrug-resistant UPEC strains, 54% were biofilm producers. Our findings further indicated that biofilm production was significantly correlated with the pap adhesin gene (p ≤ 0.05).

CONCLUSION: These findings provide molecular epidemiologic data, antibiotic resistance profiles, and the potential for biofilm formation among UPEC strains that can inform further development of the appropriate prevention and control strategies for UTIs in this region.}, } @article {pmid33343538, year = {2020}, author = {Guo, Y and Wang, Y and Wang, Y and Jin, Y and Wang, C}, title = {Heme Competition Triggers an Increase in the Pathogenic Potential of Porphyromonas gingivalis in Porphyromonas gingivalis-Candida albicans Mixed Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {596459}, pmid = {33343538}, issn = {1664-302X}, abstract = {As one of the main pathogens of periodontitis, Porphyromonas gingivalis often forms mixed biofilms with other bacteria or fungi under the gingiva, such as Candida albicans. Heme is an important iron source for P. gingivalis and C. albicans that supports their growth in the host. From the perspective of heme competition, this study aims to clarify that the competition for heme enhances the pathogenic potential of P. gingivalis during the interaction between P. gingivalis and C. albicans. Porphyromonas gingivalis single-species biofilm and P. gingivalis-C. albicans dual-species biofilm were established in a low- and high-heme environment. The results showed that the vitality of P. gingivalis was increased in the dual-species biofilm under the condition of low heme, and the same trend was observed under a laser confocal microscope. Furthermore, the morphological changes in P. gingivalis were observed by electron microscope, and the resistance of P. gingivalis in dual-species biofilm was stronger against the killing effect of healthy human serum and antibiotics. The ability of P. gingivalis to agglutinate erythrocyte was also enhanced in dual-species biofilm. These changes disappeared when heme was sufficient, which confirmed that heme competition was the cause of thepathogenicy change in P. gingivalis. Gene level analysis showed that P. gingivalis was in a superior position in the competition relationship by increasing the expression of heme utilization-related genes, such as HmuY, HmuR, HusA, and Tlr. In addition, the expression of genes encoding gingipains (Kgp, RgpA/B) was also significantly increased. They not only participate in the process of utilizing heme, but also are important components of the virulence factors of P. gingivalis. In conclusion, our results indicated that the pathogenic potential of P. gingivalis was enhanced by C. albicans through heme competition, which ultimately promoted the occurrence and development of periodontitis and, therefore, C. albicans subgingival colonization should be considered as a factor in assessing the risk of periodontitis.}, } @article {pmid33343163, year = {2020}, author = {Harika, K and Shenoy, VP and Narasimhaswamy, N and Chawla, K}, title = {Detection of Biofilm Production and Its Impact on Antibiotic Resistance Profile of Bacterial Isolates from Chronic Wound Infections.}, journal = {Journal of global infectious diseases}, volume = {12}, number = {3}, pages = {129-134}, pmid = {33343163}, issn = {0974-777X}, abstract = {BACKGROUND: Microorganisms are known to be involved in the formation of biofilm. These biofilms are often seen in chronic wound infections, surgical site infections, implants etc., These are capable of causing recalcitrant infections and most of them are also known to possess high antibiotic resistance.

OBJECTIVES: This study was conducted to detect the biofilm formation in bacterial isolates from chronic wound infections.

MATERIALS AND METHODS: In the present study, ninety two isolates from chronic wound infections were identified by MALDI-TOF-MS (bioMerieux) and VITEK-2-MS (bioMerieux). These isolates were further screened for biofilm formation by three methods i. e., Tissue Culture Plate method (TCP), Tube Method (TM) and Congo Red Agar (CRA) method. Impact of biofilm production was correlated with the antibiotic resistant pattern.

STATISTICAL ANALYSIS: Statistical analysis was done for all three methods considering TCP as Gold Standard and parameters like senitivity and specificity of TM i.e. 47.2 and 100% respectively.

RESULTS: Out of 92 isolates, biofilm formation was seen in 72 isolates (78.2%) by TCP method. 64 isolates were strong biofilm producers, 8 isolates were moderate biofilm producers and 20 isolates were nonbiofilm producing. High prevalence of biofilm formation was seen in nonhealing ulcers infected with Staphylococcus aureus followed by Klebsiella pneumoniae.

CONCLUSION: Among three screening methods used for detection of biofilm production, TCP method is considered to be a standard and most reliable for screening of biofilm formation in comparison to TM and CRA.}, } @article {pmid33342588, year = {2021}, author = {Garcia, IM and Balhaddad, AA and Ibrahim, MS and Weir, MD and Xu, HHK and Collares, FM and Melo, MAS}, title = {Antibacterial response of oral microcosm biofilm to nano-zinc oxide in adhesive resin.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {37}, number = {3}, pages = {e182-e193}, doi = {10.1016/j.dental.2020.11.022}, pmid = {33342588}, issn = {1879-0097}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Dental Cements ; Materials Testing ; Methacrylates ; Resin Cements ; Streptococcus mutans ; *Zinc Oxide/pharmacology ; }, abstract = {OBJECTIVE: Various nanoparticles are currently under investigation to impart biointeractivity for dental materials. This study aimed to: (1) formulate an experimental dental adhesive containing ZnO nanoparticles; (2) evaluate its chemical and mechanical properties; and (3) assess the antibacterial response against oral microcosm biofilm.

METHODS: Nanosized ZnO was chemically and morphologically evaluated. ZnO was incorporated at 0 (GCTRL), 2.5 (G2.5%), 5 (G5%) and 7.5 (G5%) wt.% in an experimental dental adhesive. The adhesives were evaluated for the degree of conversion (DC), flexural strength (FS), and elastic modulus (E). The antibacterial activity was evaluated using a 48h-microcosm biofilm model after the formation of acquired pellicle on samples' surfaces. Colony-forming units (CFU), metabolic activity, and live/dead staining were assessed.

RESULTS: Nanosized ZnO presented characteristic peaks of Zn-O bonds, and the particles were arranged in agglomerates. The DC ranged from 62.21 (±1.05) % for GCtrl to 46.15 (±1.23) % for G7.5% (p<0.05). G7.5% showed lower FS compared to all groups (p<0.05). Despite achieving higher E (p<0.05), G2.5% did not show differences for GCtrl regarding the FS (p>0.05). G7.5% had lower CFU/mL compared to GCtrl for mutans streptococci (p<0.05) and total microorganisms (p<0.05), besides presenting lower metabolic activity (p<0.05) and higher dead bacteria via biofilm staining.

SIGNIFICANCE: The dental adhesives' physicochemical properties were similar to commercial adhesives and in compliance with ISO recommendations. G7.5% restricted the growth of oral microcosm biofilm without impairing the physicochemical performance.}, } @article {pmid33340600, year = {2021}, author = {Rather, MA and Gupta, K and Mandal, M}, title = {Inhibition of biofilm and quorum sensing-regulated virulence factors in Pseudomonas aeruginosa by Cuphea carthagenensis (Jacq.) J. F. Macbr. Leaf extract: An in vitro study.}, journal = {Journal of ethnopharmacology}, volume = {269}, number = {}, pages = {113699}, doi = {10.1016/j.jep.2020.113699}, pmid = {33340600}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antioxidants/pharmacology ; Ascorbic Acid ; Biofilms/drug effects ; Chromatography, High Pressure Liquid ; Chromobacterium/drug effects ; Cuphea/*chemistry ; Ellagic Acid ; Flavonoids/analysis ; Hippurates ; Indoles/antagonists & inhibitors ; Medicine, Traditional/*methods ; Phenols/analysis ; Plant Extracts/*chemistry/*pharmacology ; Plant Leaves/chemistry ; Pseudomonas aeruginosa/drug effects/*physiology ; Quorum Sensing/drug effects ; Virulence Factors/*antagonists & inhibitors/metabolism ; }, abstract = {ETHNOPHARMCOLOGICAL RELEVANCE: Microbial biofilm formation, a quorum sensing (QS) regulated process, is one of the major causes of nosocomial and chronic infections, foodborne diseases, and associated deaths. Various approaches have been used to eradicate the menace of biofilm. Ethnomedicinal plants as potent antibiofilm agents are gaining a lot of interest in an era where the drug resistance is increasing and the availability of potent antibiotics is no longer promised. In this context, the methanol extract of Cuphea carthagenensis (CCMD), an ethno-medicinal and culinary herb, was evaluated as an antibiofilm and anti-QS agent against Pseudomonas aeruginosa.

AIM OF THE STUDY: The aim of the study is to evaluate the antibiofilm and anti-QS activity of an ethnomedicinal plant against a strong biofilm forming microorganism, P. aeruginosa.

METHODS: Antibiofilm activity of CCMD was demonstrated at different concentrations by Tissue Culture Plate, Test Tube method and other microscopic techniques. The effect of CCMD on QS and QS-related virulence factors viz. Pyocyanin, exopolymeric substance matrix (EPS), total protease, elastase, pyoverdin and swimming motility in P. aeruginosa were also evaluated. Antioxidant activity (DPPH & FRAP), total phenolic and flavonoid content were also checked. In order to determine the composition of the extract HPLC analysis was also performed.

RESULTS: In vitro study demonstrated a significant inhibition of biofilm formation (81.88 ± 2.57%) as well as production of QS-dependent virulence factors in P. aeruginosa. The extract also inhibited violacein production (83.31 ± 2.77%) in Chromobacterium violaceum which correlates with the reduction in QS-mediated virulence factors. The extract showed 64.79% ± 0.83% DPPH scavenging activity and reduction of ferricyanide complex (Fe[3+]) to the ferrous form (Fe[2+]) in DPPH and FRAP assay, respectively. Furthermore, the extract showed thermal stability and does not have any growth inhibitory effect on P. aeruginosa. The HPLC analysis demonstrated the presence of ellagic acid, ascorbic acid and hippuric acid in the extract.

CONCLUSION: This work is the first to demonstrate that C. carthagenensis can attenuate biofilm formation and QS-mediated virulence factors of P. aeruginosa. Further investigation is required to use this ethnomedicinal plant (CCMD) as an important source of antibiofilm agents.}, } @article {pmid33339460, year = {2020}, author = {Naderi, J and Giles, C and Saboohi, S and Griesser, HJ and Coad, BR}, title = {Combatting fungal biofilm formation by diffusive release of fluconazole from heptylamine plasma polymer coating.}, journal = {Biointerphases}, volume = {15}, number = {6}, pages = {061012}, doi = {10.1116/6.0000511}, pmid = {33339460}, issn = {1559-4106}, mesh = {Amines/chemistry ; Antifungal Agents/chemistry/metabolism/*pharmacology ; Biofilms/*drug effects ; Candida albicans/physiology ; Diffusion ; Fluconazole/chemistry/*metabolism/pharmacology ; Microbial Sensitivity Tests ; Plasma Gases/*chemistry ; Polymers/*chemistry/metabolism ; Surface Properties ; }, abstract = {A drug-eluting coating applied onto biomedical devices and implants is an appropriate way to ensure that an inhibitory concentration of antimicrobial drugs is present at the device surface, thus preventing surface colonization and subsequent biofilm formation. In this study, a thin polymer coating was applied to materials, and it acted as a drug-delivery reservoir capable of surface delivery of the antifungal drug fluconazole to amounts up to 21 μg/cm[2]. The release kinetics into aqueous solution were quantified by UV spectroscopy and conformed to the Ritger-Peppas and Korsmeyer-Peppas model. Complementary microbiological assays were used to determine effectiveness against Candida albicans attachment and biofilm formation, and against the control heptylamine plasma polymer coating without drug loading, on which substantial fungal growth occurred. Fluconazole release led to marked antifungal activity in all assays, with log 1.6 reduction in CFUs/cm[2]. Cell viability assays and microscopy revealed that fungal cells attached to the fluconazole-loaded coating remained rounded and did not form hyphae and biofilm. Thus, in vitro screening results for fluconazole-releasing surface coatings showed efficacy in the prevention of the formation of Candida albicans biofilm.}, } @article {pmid33339401, year = {2020}, author = {da Nóbrega Alves, D and Monteiro, AFM and Andrade, PN and Lazarini, JG and Abílio, GMF and Guerra, FQS and Scotti, MT and Scotti, L and Rosalen, PL and Castro, RD}, title = {Docking Prediction, Antifungal Activity, Anti-Biofilm Effects on Candida spp., and Toxicity against Human Cells of Cinnamaldehyde.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {24}, pages = {}, pmid = {33339401}, issn = {1420-3049}, mesh = {Acrolein/*analogs & derivatives/chemistry/metabolism/pharmacology ; Antifungal Agents/chemistry/metabolism/*pharmacology ; Antioxidants/chemistry ; Binding Sites ; Biofilms/*drug effects ; Candida/drug effects/*physiology ; Cell Line ; Cell Survival/drug effects ; Ergosterol/chemistry/pharmacology ; Humans ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Sorbitol/chemistry/pharmacology ; Squalene Monooxygenase/chemistry/metabolism ; }, abstract = {OBJECTIVE: This study evaluated the antifungal activity of cinnamaldehyde on Candida spp. In vitro and in situ assays were carried out to test cinnamaldehyde for its anti-Candida effects, antibiofilm activity, effects on fungal micromorphology, antioxidant activity, and toxicity on keratinocytes and human erythrocytes. Statistical analysis was performed considering α = 5%.

RESULTS: The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of cinnamaldehyde ranged from 18.91 μM to 37.83 μM. MIC values did not change in the presence of 0.8 M sorbitol, whereas an 8-fold increase was observed in the presence of ergosterol, suggesting that cinnamaldehyde may act on the cell membrane, which was subsequently confirmed by docking analysis. The action of cinnamaldehyde likely includes binding to enzymes involved in the formation of the cytoplasmic membrane in yeast cells. Cinnamaldehyde-treated microcultures showed impaired cellular development, with an expression of rare pseudo-hyphae and absence of chlamydoconidia. Cinnamaldehyde reduced biofilm adherence by 64.52% to 33.75% (p < 0.0001) at low concentrations (378.3-151.3 µM). Cinnamaldehyde did not show antioxidant properties.

CONCLUSIONS: Cinnamaldehyde showed fungicidal activity through a mechanism of action likely related to ergosterol complexation; it was non-cytotoxic to keratinocytes and human erythrocytes and showed no antioxidant activity.}, } @article {pmid33338235, year = {2021}, author = {Yong, YY and Ong, MWK and Dykes, G and Choo, WS}, title = {Betacyanin-inhibited biofilm formation of co-culture of Staphylococcus aureus and Pseudomonas aeruginosa on different polymer surfaces.}, journal = {FEMS microbiology letters}, volume = {368}, number = {1}, pages = {}, doi = {10.1093/femsle/fnaa214}, pmid = {33338235}, issn = {1574-6968}, mesh = {Amaranthus/*chemistry ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Betacyanins/*pharmacology ; Biofilms/*drug effects ; Cactaceae/*chemistry ; Plant Extracts/*pharmacology ; Polymers/analysis ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A combination of each betacyanin fraction (0.625 mg mL-1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24-3.84 and 1.25-3.52 to 0.81-2.63 and 0.80-1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0-1.3 log CFU cm-2 bacterial attachment on polymer surfaces such as polyvinyl chloride, polyethylene, polypropylene and silicone rubber. This study demonstrated an increase in biofilm-inhibiting activity against biofilms formed by two species using combined fractions than that by using single fractions. Betacyanins found in different plants could collectively be used to potentially decrease the risk of biofilm-associated infections caused by these bacteria on hydrophobic polymers.}, } @article {pmid33336805, year = {2021}, author = {Cahill, SV and Kwon, HK and Back, J and Lee, I and Lee, S and Alder, KD and Hao, Z and Yu, KE and Dussik, CM and Kyriakides, TR and Lee, FY}, title = {Locally delivered adjuvant biofilm-penetrating antibiotics rescue impaired endochondral fracture healing caused by MRSA infection.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {39}, number = {2}, pages = {402-414}, doi = {10.1002/jor.24965}, pmid = {33336805}, issn = {1554-527X}, support = {R01AR056246/NH/NIH HHS/United States ; R01AR073607/NH/NIH HHS/United States ; R01AR073607/NH/NIH HHS/United States ; }, mesh = {Animals ; Antibiotics, Antitubercular/*administration & dosage ; Bacterial Load/drug effects ; Drug Evaluation, Preclinical ; Fracture Healing/drug effects ; Fractures, Open/*complications ; Hydrogels ; Male ; Methicillin-Resistant Staphylococcus aureus ; Mice, Inbred C57BL ; Osteomyelitis/*drug therapy/etiology ; Rifampin/*administration & dosage ; Staphylococcal Infections/*drug therapy/etiology ; }, abstract = {Infection is a devastating complication following an open fracture. We investigated whether local rifampin-loaded hydrogel can combat infection and improve healing in a murine model of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis. A transverse fracture was made at the tibia midshaft of C57BL/6J mice aged 10-12 weeks and stabilized with an intramedullary pin. A total of 1 × 10[6] colony-forming units (CFU) of MRSA was inoculated. A collagen-based hydrogel containing low-dose (60 μg) and high-dose (300 μg) rifampin was applied before closure. Postoperative treatment response was assessed through bacterial CFU counts from tissue and hardware, tibial radiographs and microcomputed tomography (μCT), immunohistochemistry, and histological analyses. All untreated MRSA-infected fractures progressed to nonunion by 28 days with profuse MRSA colonization. Infected fractures demonstrated decreased soft callus formation on safranin O stain compared to controls. Areas of dense interleukin-1β stain were associated with poor callus formation. High-dose rifampin hydrogels reduced the average MRSA load in tissue (p < 0.0001) and implants (p = 0.041). Low-dose rifampin hydrogels reduced tissue bacterial load by 50% (p = 0.021). Among sterile models, 88% achieved union compared to 0% of those infected. Mean radiographic union scale in tibia scores improved from 6 to 8.7 with high-dose rifampin hydrogel (p = 0.024) and to 10 with combination local/systemic rifampin therapy (p < 0.0001). μCT demonstrated reactive bone formation in MRSA infection. Histology demonstrated restored fracture healing with bacterial elimination. Rifampin-loaded hydrogels suppressed osteomyelitis, prevented implant colonization, and improved healing. Systemic rifampin was more effective at eliminating infection and improving fracture healing. Further investigation into rifampin-loaded hydrogels is required to correlate these findings with clinical efficacy.}, } @article {pmid33334876, year = {2021}, author = {Breslawec, AP and Wang, S and Li, C and Poulin, MB}, title = {Anionic amino acids support hydrolysis of poly-β-(1,6)-N-acetylglucosamine exopolysaccharides by the biofilm dispersing glycosidase Dispersin B.}, journal = {The Journal of biological chemistry}, volume = {296}, number = {}, pages = {100203}, pmid = {33334876}, issn = {1083-351X}, mesh = {Aggregatibacter actinomycetemcomitans/*metabolism ; Amino Acids/*metabolism ; Bacterial Proteins/*metabolism ; Biofilms ; Glycoside Hydrolases/*metabolism ; Hydrolysis ; Models, Molecular ; beta-Glucans/*metabolism ; }, abstract = {The exopolysaccharide poly-β-(1→6)-N-acetylglucosamine (PNAG) is a major structural determinant of bacterial biofilms responsible for persistent and nosocomial infections. The enzymatic dispersal of biofilms by PNAG-hydrolyzing glycosidase enzymes, such as Dispersin B (DspB), is a possible approach to treat biofilm-dependent bacterial infections. The cationic charge resulting from partial de-N-acetylation of native PNAG is critical for PNAG-dependent biofilm formation. We recently demonstrated that DspB has increased catalytic activity on de-N-acetylated PNAG oligosaccharides, but the molecular basis for this increased activity is not known. Here, we analyze the role of anionic amino acids surrounding the catalytic pocket of DspB in PNAG substrate recognition and hydrolysis using a combination of site-directed mutagenesis, activity measurements using synthetic PNAG oligosaccharide analogs, and in vitro biofilm dispersal assays. The results of these studies support a model in which bound PNAG is weakly associated with a shallow anionic groove on the DspB protein surface with recognition driven by interactions with the -1 GlcNAc residue in the catalytic pocket. An increased rate of hydrolysis for cationic PNAG was driven, in part, by interaction with D147 on the anionic surface. Moreover, we identified that a DspB mutant with improved hydrolysis of fully acetylated PNAG oligosaccharides correlates with improved in vitro dispersal of PNAG-dependent Staphylococcus epidermidis biofilms. These results provide insight into the mechanism of substrate recognition by DspB and suggest a method to improve DspB biofilm dispersal activity by mutation of the amino acids within the anionic binding surface.}, } @article {pmid33334714, year = {2021}, author = {Mello, TP and Lackner, M and Branquinha, MH and Santos, ALS}, title = {Impact of biofilm formation and azoles' susceptibility in Scedosporium/Lomentospora species using an in vitro model that mimics the cystic fibrosis patients' airway environment.}, journal = {Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society}, volume = {20}, number = {2}, pages = {303-309}, doi = {10.1016/j.jcf.2020.12.001}, pmid = {33334714}, issn = {1873-5010}, mesh = {Antifungal Agents/*pharmacology ; Azoles/*pharmacology ; Biofilms/*drug effects ; Cystic Fibrosis/*complications ; Drug Resistance, Fungal ; Humans ; In Vitro Techniques ; Invasive Fungal Infections/drug therapy ; Lung Diseases, Fungal/drug therapy/microbiology ; Microbial Sensitivity Tests ; Scedosporium/*drug effects ; }, abstract = {BACKGROUND: Scedosporium species are the second most isolated filamentous fungi from cystic fibrosis (CF) patients; however, little is known about their virulence aspects in a CF environment. In this context, the current study aimed to evaluate the (i) antifungal susceptibility profiles, (ii) ability to form biofilm and (iii) impact of biofilm formation on the susceptibility to azoles in 21 clinical isolates of Scedosporium recovered from CF patients.

METHODS: Scedosporium apiospermum (n=6), S. aurantiacum (n=6), S. minutisporum (n=3) and Lomentospora prolificans (n=6) were firstly used to compare the antifungal susceptibility profile using a standard culture broth (RPMI-1640) and a mucin (M)-containing synthetic CF sputum medium (SCFM). The ability to form biofilms was investigated in polystyrene microtiter plates containing Sabouraud-dextrose (a classical medium), SCFM and SCFM+M. Mature biofilms were tested for their susceptibility to azoles by microdilution assay.

RESULTS: Our results showed that the minimum inhibitory concentrations (MICs) for planktonic conidia ranged from 0.25 to >16.0 mg/L for voriconazole and 1.0 to >16.0 mg/L for posaconazole. Overall, the MICs for azoles increased from 2- to 8-folds when the susceptibility tests were performed using SCFM+M compared to RPMI-1640. All fungi formed robust biofilms on polystyrene surface at 72 h, with a significant increase in the MICs (ranging from 128- to 1024-times) against both azoles compared to the planktonic cells.

CONCLUSION: These findings confirm the challenge of antifungal treatment of CF patients infected with Scedosporium/Lomentospora and also demonstrated a strong biofilm formation, with extensive increase in antifungal resistance, triggered underconditions mimicking the CF patient airway.}, } @article {pmid33334522, year = {2021}, author = {Mao, G and Liang, J and Wang, Q and Zhao, C and Bai, Y and Liu, R and Liu, H and Qu, J}, title = {Epilithic biofilm as a reservoir for functional virulence factors in wastewater-dominant rivers after WWTP upgrade.}, journal = {Journal of environmental sciences (China)}, volume = {101}, number = {}, pages = {27-35}, doi = {10.1016/j.jes.2020.05.014}, pmid = {33334522}, issn = {1001-0742}, mesh = {Biofilms ; Ecosystem ; Humans ; RNA, Ribosomal, 16S/genetics ; *Rivers ; Virulence Factors ; *Wastewater ; }, abstract = {Virulence factors (VFs) confer upon pathogens the ability to cause various types of damage or diseases. Wastewater treatment plants (WWTPs) are important point sources for the emission of pathogens and VFs into receiving rivers. Conventional WWTP upgrades are often implemented to improve the water quality of receiving ecosystems. However, knowledge on the pathogens, VFs, and health risks to receiving aquatic ecosystems after upgrade remains limited. In this study, we investigated detailed pathogenic information, including taxa, pathogenicity, and health risk, in two wastewater-dominant rivers after WWTP upgrade. Using 16S rRNA gene sequencing, we screened 14 potential pathogens in water and epilithic biofilm samples, though they were significantly more enriched in the biofilms. Combining 16S rRNA and metagenomic sequencing data, we identified Pseudomonas and Aeromonas as the dominant pathogenic taxa carrying functional VFs (e.g., mobility and offensive) in the epilithic biofilm. Moreover, strong pathogen-specific VF-host co-occurrence events were observed in the epilithic biofilm samples, indicating the importance of biofilms as reservoirs and vehicles for VFs. Further, we demonstrated that mobility VF is crucial for biofilm formation and pathogens in biofilm carrying offensive VF may be highly invasive. Quantification and health risk assessment suggested that the skin contact risk of P. aeruginosa carrying VFs was higher than the acceptable probability of 10[-4] in both water and epilithic biofilm samples, which may threaten ecological and human health.}, } @article {pmid33334195, year = {2020}, author = {Martins, ML and Monteiro, ASN and Vieira, TI and Guimarães, MBCT and de Abreu, LCL and Cabral, LM and Cavalcanti, YW and Maia, LC and Fonseca-Gonçalves, A}, title = {Effect of xylitol tablets with and without red propolis on salivary parameters, dental biofilm and sensory acceptability of adolescents: a randomized crossover clinical trial.}, journal = {Biofouling}, volume = {36}, number = {10}, pages = {1182-1195}, doi = {10.1080/08927014.2020.1858063}, pmid = {33334195}, issn = {1029-2454}, mesh = {Adolescent ; *Biofilms ; Humans ; Micrococcaceae ; *Propolis ; Saliva ; Streptococcus mutans ; Tablets ; Xylitol ; }, abstract = {The effect of xylitol tablets with (XPT) and without (XT) red propolis on salivary parameters, dental biofilm and acceptability of adolescents was evaluated through a blinded randomized crossover clinical trial. Healthy volunteers were allocated in the XPT and XT groups with a 30-day washout period for consumption of two tablets/dayfor seven days. An increase in salivary parameters was only observed immediately after tablet consumption, without differences between XPT and XT. The results for total microorganisms were similar, but XT was better in controlling Streptococcus spp. Rothia dentocariosa and Streptococcus salivarius were the most frequent in the biofilm and saliva, respectively. XPT and XT showed similar acceptability, with the highest purchase intention for XT. Although propolis did not enhance the properties of XT, further studies testing different protocols and follow-up are necessary; XT controlled Streptococcus spp. in biofilms, which demonstrate its potential for clinical application.}, } @article {pmid33333723, year = {2020}, author = {Tektas, S and Thurnheer, T and Eliades, T and Attin, T and Karygianni, L}, title = {Initial Bacterial Adhesion and Biofilm Formation on Aligner Materials.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33333723}, issn = {2079-6382}, abstract = {The present study aims to assess the initial bacterial adhesion and biofilm formation on different aligner materials. A total of four different aligner materials, CA-medium (CAM), copolyester (COP), Duran (DUR), Erkodur (ERK), were tested. Stimulated human saliva was obtained from six healthy volunteers. Salivary bacteria were harvested by centrifugation, and 1 mL of the salivary suspension was injected onto each sample surface for 2 h and 3 days, respectively. The samples were then washed twice with 5 mL 0.9% NaCl solution, and non-adherent bacteria were removed. The adherent microorganisms were dislodged from the sample surfaces after ultrasonication for 4 min in 1 mL 0.9% NaCl on ice. After the incubation of the adherent salivary bacteria under both aerobic and anaerobic conditions on Columbia blood agar plates at 37 °C and 5% CO2 and in anaerobic jars overnight, several dilutions thereof were used for the determination of CFUs. This protocol was applied three times, obtaining an average of nine independent measurements for each material group. Overall, the differences between the tested aligner materials as well as between the materials and controls were not of statistical significance (p > 0.05). Regarding initial bacterial attachment and biofilm formation, the tested aligner materials are comparable to enamel and metal orthodontic brackets and can be therefore considered for clinical use. The four tested aligner materials CAM, COP, DUR, ERK showed no significant differences in initial microbial attachment and biofilm formation of aerobic and anaerobic species compared to enamel and conventional brackets.}, } @article {pmid33333670, year = {2020}, author = {Zhao, ZJ and Liu, XW and Zhang, XQ and Guo, MY and Hu, Y and Liu, DM and Li, YW}, title = {[Research progress on the regulation mechanism of Pseudomonas aeruginosa biofilm].}, journal = {Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]}, volume = {54}, number = {12}, pages = {1469-1472}, doi = {10.3760/cma.j.cn112150-20200714-01002}, pmid = {33333670}, issn = {0253-9624}, support = {132102310244//Henan Province Science and Technology Research Project/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Pseudomonas aeruginosa ; }, abstract = {Pseudomonas aeruginosa is one of the common multidrug-resistant bacteria in the clinic. Because it can produce a "protective" biofilm, it can affect the penetration and killing efficacy of antibacterial drugs, leading to the formation of a persistent and persistent chronic infection in the host. Biofilms make Pseudomonas aeruginosa resistant to antibacterials and evasive to the host's immune system. Therefore, traditional conventional antibacterials are difficult to achieve effective bactericidal treatment. Understanding the process of P. aeruginosa biofilm formation and the regulatory mechanisms that affect biofilms can provide ideas and methods for our future research on new antibacterial drugs.}, } @article {pmid33332404, year = {2020}, author = {Miyagi, M and Wilson, R and Saigusa, D and Umeda, K and Saijo, R and Hager, CL and Li, Y and McCormick, T and Ghannoum, MA}, title = {Indole-3-acetic acid synthesized through the indole-3-pyruvate pathway promotes Candida tropicalis biofilm formation.}, journal = {PloS one}, volume = {15}, number = {12}, pages = {e0244246}, pmid = {33332404}, issn = {1932-6203}, support = {R01 AI145289/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/drug effects/*growth & development ; Candida tropicalis/drug effects/*growth & development/metabolism ; Candidiasis/*microbiology ; Humans ; Indoleacetic Acids/*pharmacology ; Indoles/*metabolism ; Plant Growth Regulators/pharmacology ; Signal Transduction ; }, abstract = {We previously found that the elevated abundance of the fungus Candida tropicalis is positively correlated with the bacteria Escherichia coli and Serratia marcescens in Crohn's disease patients and the three pathogens, when co-cultured, form a robust mixed-species biofilm. The finding suggests that these three pathogens communicate and promote biofilm formation, possibly through secretion of small signaling molecules. To identify candidate signaling molecules, we carried out a metabolomic analysis of the single-species and triple-species cultures of the three pathogens. This analysis identified 15 metabolites that were highly increased in the triple-species culture. One highly induced metabolite was indole-3-acetic acid (IAA), which has been shown to induce filamentation of certain fungi. We thus tested the effect of IAA on biofilm formation of C. tropicalis and demonstrated that IAA promotes biofilm formation of C. tropicalis. Then, we carried out isotope tracing experiments using 13C-labeled-tryptophan as a precursor to uncover the biosynthesis pathway of IAA in C. tropicalis. The results indicated that C. tropicalis synthesizes IAA through the indole-3-pyruvate pathway. Further studies using inhibitors of the indole-3-pyruvate pathway are warranted to decipher the mechanisms by which IAA influences biofilm formation.}, } @article {pmid33331390, year = {2020}, author = {Scorzoni, L and Menezes, RT and Pereira, TC and Oliveira, PS and Ribeiro, FC and Santos, ELS and Fugisaki, LRO and Oliveira, LD and Amorim, JBO}, title = {Antifungal and anti-biofilm effect of the calcium channel blocker verapamil on non-albicans Candida species.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {92}, number = {4}, pages = {e20200703}, doi = {10.1590/0001-3765202020200703}, pmid = {33331390}, issn = {1678-2690}, mesh = {*Antifungal Agents/pharmacology ; Biofilms ; Calcium Channel Blockers/pharmacology ; *Candida ; Candida albicans ; Humans ; Microbial Sensitivity Tests ; Verapamil/pharmacology ; }, abstract = {Candida is a human fungal pathogen that causes a wide range of diseases. Candida albicans is the main etiologic agent in these diseases; however, infections can be caused by non-albicans Candida species. Virulence factors such as biofilm production, which protect the fungus from host immunity and anti-fungal drugs, are important for the infection. Therefore, available antifungal drugs for candidiasis treatment are limited and the investigation of new and effective drugs is needed. Verapamil is a calcium channel blocker with an inhibitory effect on hyphae development, adhesion, and colonization of C. albicans. In this study, we investigated the effect of verapamil on cell viability and its antifungal and anti-biofilm activity in non-albicans Candida species. Verapamil was not toxic to keratinocyte cells; moreover, C. krusei, C. parapsilosis, and C. glabrata were susceptible to verapamil with a minimal inhibitory concentration (MIC) of 1250 μM; in addition, this drug displayed fungistatic effect at the evaluated concentrations. After treatment with verapamil, reduced viability, biomass, and mitochondrial activity were observed in biofilms of the non-albicans Candida species C. krusei, C. glabrata, and C. parapsilosis. These findings highlight the importance of the study of verapamil as an alternative treatment for infections caused by non-albicans Candida species.}, } @article {pmid33330139, year = {2020}, author = {Shagieva, E and Teren, M and Michova, H and Strakova, N and Karpiskova, R and Demnerova, K}, title = {Adhesion, Biofilm Formation, and luxS Sequencing of Campylobacter jejuni Isolated From Water in the Czech Republic.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {596613}, pmid = {33330139}, issn = {2235-2988}, mesh = {Animals ; Bacterial Proteins ; Biofilms ; *Campylobacter jejuni/genetics ; Carbon-Sulfur Lyases ; Czech Republic ; Humans ; Quorum Sensing ; Water ; }, abstract = {The microaerophilic pathogen Campylobacter jejuni is a leading bacterial cause of human gastroenteritis in developed countries. Even though it has a reputation as a fastidious organism, C. jejuni is widespread and can be easily isolated from various animals, food, and environmental sources. It is suggested that an ability to form biofilms is probably necessary for the survival of C. jejuni under harsh environmental conditions. The first step required for successful biofilm formation is adhesion to a suitable surface. Therefore, in this work, the degree of adhesion was evaluated, followed by characterization and quantification of biofilms using confocal laser scanning microscopy (CLSM). A total of 15 isolates of C. jejuni were used in the experiments (12 isolates from surface and waste waters, 1 human clinical, 1 food and 1 ACTT BAA-2151 collection strain, all samples originated from the Czech Republic). Regardless of the sample origin, all C. jejuni isolates were able to adhere to the polystyrene surface within 30 min, with the number of attached cells increasing with the time of incubation. The resulting data showed that all isolates were able to form complex voluminous biofilms after 24 h of cultivation. The average amount of biovolume ranged from 3.59 × 10[6] µm[3] to 17.50 × 10[6] µm[3] in isolates obtained from different sources of water, 16.79 × 10[6] µm[3] in the food isolate and 10.92 × 10[6] µm[3] in the collection strain. However, the highest amount of biomass was produced by the human clinical isolate (25.48 × 10[6] µm[3]). Similar to the quantity, the architecture of the biofilms also differed, from a rugged flat monolayer of cells to large clustered structures. Further, all isolates were tested for the presence of the luxS gene, as the luxS/AI-2 (autoinducer-2) quorum sensing pathway has been previously connected with enhanced biofilm formation. Two isolates originated from surface waters did not possess the luxS gene. These isolates formed thinner and sparser biofilms lacking the presence of significant clusters. However, the ability to adhere to the surface was preserved. The sequencing of the luxS-containing fragments shown a high similarity of the luxS gene among the isolates.}, } @article {pmid33330136, year = {2020}, author = {Phuengmaung, P and Somparn, P and Panpetch, W and Singkham-In, U and Wannigama, DL and Chatsuwan, T and Leelahavanichkul, A}, title = {Coexistence of Pseudomonas aeruginosa With Candida albicans Enhances Biofilm Thickness Through Alginate-Related Extracellular Matrix but Is Attenuated by N-acetyl-l-cysteine.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {594336}, pmid = {33330136}, issn = {2235-2988}, mesh = {Acetylcysteine ; Alginates ; Animals ; Biofilms ; *Candida albicans ; Extracellular Matrix ; Mice ; Proteomics ; *Pseudomonas aeruginosa ; }, abstract = {Bacteria and Candidaalbicans are prominent gut microbiota, and the translocation of these organisms into blood circulation might induce mixed-organism biofilms, which warrants the exploration of mixed- versus single-organism biofilms in vitro and in vivo. In single-organism biofilms, Acinetobacter baumannii and Pseudomonas aeruginosa (PA) produced the least and the most prominent biofilms, respectively. C. albicans with P. aeruginosa (PA+CA) induced the highest biofilms among mixed-organism groups as determined by crystal violet straining. The sessile form of PA+CA induced higher macrophage responses than sessile PA, which supports enhanced immune activation toward mixed-organism biofilms. In addition, Candida incubated in pre-formed Pseudomonas biofilms (PA>CA) produced even higher biofilms than PA+CA (simultaneous incubation of both organisms) as determined by fluorescent staining on biofilm matrix (AF647 color). Despite the initially lower bacteria during preparation, bacterial burdens by culture in mixed-organism biofilms (PA+CA and PA>CA) were not different from biofilms of PA alone, supporting Candida-enhanced Pseudomonas growth. Moreover, proteomic analysis in PA>CA biofilms demonstrated high AlgU and mucA with low mucB when compared with PA alone or PA+CA, implying an alginate-related mucoid phenotype in PA>CA biofilms. Furthermore, mice with PA>CA biofilms demonstrated higher bacteremia with more severe sepsis compared with mice with PA+CA biofilms. This is possibly due to the different structures. Interestingly, l-cysteine, a biofilm matrix inhibitor, attenuated mixed-organism biofilms both in vitro and in mice. In conclusion, Candida enhanced Pseudomonas alginate-related biofilm production, and Candida presentation in pre-formed Pseudomonas biofilms might alter biofilm structures that affect clinical manifestations but was attenuated by l-cysteine.}, } @article {pmid33329502, year = {2020}, author = {Huang, Y and Pei, Q and Deng, R and Zheng, X and Guo, J and Guo, D and Yang, Y and Liang, S and Shi, C}, title = {Inactivation Efficacy of 405 nm LED Against Cronobacter sakazakii Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {610077}, pmid = {33329502}, issn = {1664-302X}, abstract = {The objectives of this study were to evaluate the inactivation efficacy of a 405-nm light-emitting diode (LED) against Cronobacter sakazakii biofilm formed on stainless steel and to determine the sensitivity change of illuminated biofilm to food industrial disinfectants. The results showed that LED illumination significantly reduced the population of viable biofilm cells, showing reduction of 2.0 log (25°C), 2.5 log (10°C), and 2.0 log (4°C) between the non-illuminated and LED-illuminated groups at 4 h. Images of confocal laser scanning microscopy and scanning electron microscopy revealed the architectural damage to the biofilm caused by LED illumination, which involved destruction of the stereoscopic conformation of the biofilm. Moreover, the loss of biofilm components (mainly polysaccharide and protein) was revealed by attenuated total reflection Fourier-transformed infrared spectroscopy, and the downregulation of genes involved in C. sakazakii biofilm formation was confirmed by real time quantitative PCR analysis, with greatest difference observed in fliD. In addition, the sensitivity of illuminated-biofilm cells to disinfectant treatment was found to significantly increased, showing the greatest sensitivity change with 1.5 log reduction between non-LED and LED treatment biofilms in the CHX-treated group. These results indicated that 405 nm LED illumination was effective at inactivating C. sakazakii biofilm adhering to stainless steel. Therefore, the present study suggests the potential of 405 nm LED technology in controlling C. sakazakii biofilms in food processing and storage, minimizing the risk of contamination.}, } @article {pmid33329497, year = {2020}, author = {Qu, Y and McGiffin, D and Kure, C and McLean, J and Duncan, C and Peleg, AY}, title = {In vitro Evaluation of Medihoney Antibacterial Wound Gel as an Anti-biofilm Agent Against Ventricular Assist Device Driveline Infections.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {605608}, pmid = {33329497}, issn = {1664-302X}, abstract = {Objectives: In adult ventricular assist device (VAD) programs in Australian hospitals, Medihoney Antibacterial Wound Gel (MAWG) is routinely used at the skin exit-site of VAD drivelines to prevent infections; however, its effectiveness remains unclear. Our aim was to assess antimicrobial activity of Medihoney wound gel, using in vitro models that mimic clinical biofilms grown at the driveline exit-site. Methods: Antimicrobial susceptibility testing of MAWG was performed for 24 clinical isolates grown under planktonic conditions, and four representative strains grown as biofilms. Different antimicrobial mechanisms of MAWG were assessed respectively for their relative contribution to its anti-biofilm activity. A colony biofilm assay and a drip-flow biofilm reactor assay mimicking the driveline exit-site environment were used to evaluate the activity of MAWG against biofilm growth at the driveline exit-site. Results: MAWG demonstrated species-specific activity against planktonic cultures [minimum inhibitory concentrations (MICs), 5-20% weight/volume (W/V) for Staphylococcus species, 20->40% (W/V) for Pseudomonas aeruginosa and Candida species]. Higher concentrations [MICs, 30->80% (W/V)] were able to inhibit biofilm growth, but failed to eradicate pre-established biofilms. The anti-biofilm properties of MAWG were multi-faceted, with the often-advertised "active" ingredient methylglyoxal (MGO) playing a less important role. The colony biofilm assay and the drip-flow biofilm reactor assay suggested that MAWG was unable to kill biofilms pre-established in a driveline exit-site environment, or effectively prevent planktonic cells from forming adherent monolayers and further developing mature biofilms. Conclusion: Our work suggests a suboptimal effectiveness of MAWG in preventing driveline infections due to biofilm development.}, } @article {pmid33328348, year = {2020}, author = {Schiller, H and Schulze, S and Mutan, Z and de Vaulx, C and Runcie, C and Schwartz, J and Rados, T and Bisson Filho, AW and Pohlschroder, M}, title = {Haloferax volcanii Immersed Liquid Biofilms Develop Independently of Known Biofilm Machineries and Exhibit Rapid Honeycomb Pattern Formation.}, journal = {mSphere}, volume = {5}, number = {6}, pages = {}, pmid = {33328348}, issn = {2379-5042}, mesh = {*Biofilms ; Fimbriae Proteins/genetics/*metabolism ; Fimbriae, Bacterial/metabolism/ultrastructure ; Glycosylation ; Haloferax volcanii/cytology/genetics/*metabolism ; Polysaccharides/metabolism ; }, abstract = {The ability to form biofilms is shared by many microorganisms, including archaea. Cells in a biofilm are encased in extracellular polymeric substances that typically include polysaccharides, proteins, and extracellular DNA, conferring protection while providing a structure that allows for optimal nutrient flow. In many bacteria, flagella and evolutionarily conserved type IV pili are required for the formation of biofilms on solid surfaces or floating at the air-liquid interface of liquid media. Similarly, in many archaea it has been demonstrated that type IV pili and, in a subset of these species, archaella are required for biofilm formation on solid surfaces. Additionally, in the model archaeon Haloferax volcanii, chemotaxis and AglB-dependent glycosylation play important roles in this process. H. volcanii also forms immersed biofilms in liquid cultures poured into petri dishes. This study reveals that mutants of this haloarchaeon that interfere with the biosynthesis of type IV pili or archaella, as well as a chemotaxis-targeting transposon and aglB deletion mutants, lack obvious defects in biofilms formed in liquid cultures. Strikingly, we have observed that these liquid-based biofilms are capable of rearrangement into honeycomb-like patterns that rapidly form upon removal of the petri dish lid, a phenomenon that is not dependent on changes in light or oxygen concentration but can be induced by controlled reduction of humidity. Taken together, this study demonstrates that H. volcanii requires novel, unidentified strategies for immersed liquid biofilm formation and also exhibits rapid structural rearrangements.IMPORTANCE This first molecular biological study of archaeal immersed liquid biofilms advances our basic biological understanding of the model archaeon Haloferax volcanii Data gleaned from this study also provide an invaluable foundation for future studies to uncover components required for immersed liquid biofilms in this haloarchaeon and also potentially for liquid biofilm formation in general, which is poorly understood compared to the formation of biofilms on surfaces. Moreover, this first description of rapid honeycomb pattern formation is likely to yield novel insights into the underlying structural architecture of extracellular polymeric substances and cells within immersed liquid biofilms.}, } @article {pmid33327555, year = {2020}, author = {Krzyżek, P and Gościniak, G and Fijałkowski, K and Migdał, P and Dziadas, M and Owczarek, A and Czajkowska, J and Aniołek, O and Junka, A}, title = {Potential of Bacterial Cellulose Chemisorbed with Anti-Metabolites, 3-Bromopyruvate or Sertraline, to Fight against Helicobacter pylori Lawn Biofilm.}, journal = {International journal of molecular sciences}, volume = {21}, number = {24}, pages = {}, pmid = {33327555}, issn = {1422-0067}, support = {SUB.A130.19.021//Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu/ ; ST.D230.18.008//Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu/ ; }, mesh = {Biofilms/growth & development ; Cellulose/*metabolism ; Helicobacter pylori/growth & development/metabolism/ultrastructure ; Microbial Sensitivity Tests ; Pyruvates/*metabolism ; Sertraline/*metabolism ; }, abstract = {Helicobacter pylori is a bacterium known mainly of its ability to cause persistent inflammations of the human stomach, resulting in peptic ulcer diseases and gastric cancers. Continuous exposure of this bacterium to antibiotics has resulted in high detection of multidrug-resistant strains and difficulties in obtaining a therapeutic effect. The purpose of the present study was to determine the usability of bacterial cellulose (BC) chemisorbed with 3-bromopyruvate (3-BP) or sertraline (SER) to act against lawn H. pylori biofilms. The characterization of BC carriers was made using a N2 adsorption/desorption analysis, tensile strength test, and scanning electron microscopy (SEM) observations. Determination of an antimicrobial activity was performed using a modified disk-diffusion method and a self-designed method of testing antibacterial activity against biofilm microbial forms. In addition, bacterial morphology was checked by SEM. It was found that BC disks were characterized by a high cross-linking and shear/stretch resistance. Growth inhibition zones for BC disks chemisorbed with 2 mg of SER or 3-BP were equal to 26.5-27.5 mm and 27-30 mm, respectively. The viability of lawn biofilm H. pylori cells after a 4-h incubation with 2 mg SER or 3-BP chemisorbed on BC disks was ≥4 log lower, suggesting their antibacterial effect. SEM observations showed a number of morphostructural changes in H. pylori cells exposed to these substances. Concluding, SER and 3-BP chemisorbed on BC carriers presented a promising antibacterial activity against biofilm H. pylori cells in in vitro conditions.}, } @article {pmid33327403, year = {2020}, author = {Abusrewil, S and Brown, JL and Delaney, CD and Butcher, MC and Kean, R and Gamal, D and Scott, JA and McLean, W and Ramage, G}, title = {Filling the Void: An Optimized Polymicrobial Interkingdom Biofilm Model for Assessing Novel Antimicrobial Agents in Endodontic Infection.}, journal = {Microorganisms}, volume = {8}, number = {12}, pages = {}, pmid = {33327403}, issn = {2076-2607}, support = {1/CX/CSRD VA/United States ; BB/P504567/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {There is a growing realization that endodontic infections are often polymicrobial, and may contain Candida spp. Despite this understanding, the development of new endodontic irrigants and models of pathogenesis remains limited to mono-species biofilm models and is bacterially focused. The purpose of this study was to develop and optimize an interkingdom biofilm model of endodontic infection and use this to test suitable anti-biofilm actives. Biofilms containing Streptococcus gordonii, Fusobacterium nucleatum, Porphyromonas gingivalis, and Candida albicans were established from ontological analysis. Biofilms were optimized in different media and atmospheric conditions, prior to quantification and imaging, and subsequently treated with chlorhexidine, EDTA, and chitosan. These studies demonstrated that either media supplemented with serum were equally optimal for biofilm growth, which were dominated by S. gordonii, followed by C. albicans. Assessment of antimicrobial activity showed significant effectiveness of each antimicrobial, irrespective of serum. Chitosan was most effective (3 log reduction), and preferentially targeted C. albicans in both biofilm treatment and inhibition models. Chitosan was similarly effective at preventing biofilm growth on a dentine substrate. This study has shown that a reproducible and robust complex interkingdom model, which when tested with the antifungal chitosan, supports the notion of C. albicans as a key structural component.}, } @article {pmid33326455, year = {2020}, author = {Wongkaewkhiaw, S and Taweechaisupapong, S and Thanaviratananich, S and Bolscher, JGM and Nazmi, K and Anutrakunchai, C and Chareonsudjai, S and Kanthawong, S}, title = {D-LL-31 enhances biofilm-eradicating effect of currently used antibiotics for chronic rhinosinusitis and its immunomodulatory activity on human lung epithelial cells.}, journal = {PloS one}, volume = {15}, number = {12}, pages = {e0243315}, pmid = {33326455}, issn = {1932-6203}, mesh = {A549 Cells ; Adolescent ; Adult ; Aged ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Bacteria/*growth & development ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects/growth & development ; Chronic Disease ; Epithelial Cells/metabolism/*microbiology ; Female ; Humans ; Lung/metabolism/*microbiology/pathology ; Male ; Middle Aged ; *Rhinitis/drug therapy/microbiology/pathology ; *Sinusitis/drug therapy/microbiology/pathology ; Cathelicidins ; }, abstract = {Chronic rhinosinusitis (CRS) is a chronic disease that involves long-term inflammation of the nasal cavity and paranasal sinuses. Bacterial biofilms present on the sinus mucosa of certain patients reportedly exhibit resistance against traditional antibiotics, as evidenced by relapse, resulting in severe disease. The aim of this study was to determine the killing activity of human cathelicidin antimicrobial peptides (LL-37, LL-31) and their D-enantiomers (D-LL-37, D-LL-31), alone and in combination with conventional antibiotics (amoxicillin; AMX and tobramycin; TOB), against bacteria grown as biofilm, and to investigate the biological activities of the peptides on human lung epithelial cells. D-LL-31 was the most effective peptide against bacteria under biofilm-stimulating conditions based on IC50 values. The synergistic effect of D-LL-31 with AMX and TOB decreased the IC50 values of antibiotics by 16-fold and could eliminate the biofilm matrix in all tested bacterial strains. D-LL-31 did not cause cytotoxic effects in A549 cells at 25 μM after 24 h of incubation. Moreover, a cytokine array indicated that there was no significant induction of the cytokines involving in immunopathogenesis of CRS in the presence of D-LL-31. However, a tissue-remodeling-associated protein was observed that may prevent the progression of nasal polyposis in CRS patients. Therefore, a combination of D-LL-31 with AMX or TOB may improve the efficacy of currently used antibiotics to kill biofilm-embedded bacteria and eliminate the biofilm matrix. This combination might be clinically applicable for treatment of patients with biofilm-associated CRS.}, } @article {pmid33324819, year = {2020}, author = {Selvaraj, A and Valliammai, A and Muthuramalingam, P and Priya, A and Suba, M and Ramesh, M and Karutha Pandian, S}, title = {Carvacrol Targets SarA and CrtM of Methicillin-Resistant Staphylococcus aureus to Mitigate Biofilm Formation and Staphyloxanthin Synthesis: An In Vitro and In Vivo Approach.}, journal = {ACS omega}, volume = {5}, number = {48}, pages = {31100-31114}, pmid = {33324819}, issn = {2470-1343}, abstract = {Carvacrol is an essential oil traditionally used in culinary processes as spice due to its aromatic nature and also known for various biological activities. In the present study, the antivirulence efficacy of carvacrol against methicillin-resistant Staphylococcus aureus (MRSA) is explored. MRSA is an opportunistic pathogen capable of causing various superficial and systemic infections in humans. Biofilm formation and virulence factors of MRSA are responsible for its pathogenesis and resistance. Hence, the aim of this study was to explore the antibiofilm and antivirulence efficacy of carvacrol against MRSA. Carvacrol at 75 μg/mL inhibited MRSA biofilm by 93%, and it also decreased the biofilm formation on polystyrene and glass surfaces. Further, microscopic analyses revealed the reduction in microcolony formation and collapsed structure of biofilm upon carvacrol treatment. The growth curve analysis and the Alamar blue assay showed the nonfatal effect of carvacrol on MRSA. Further, carvacrol significantly reduced the production of MRSA biofilm-associated slime and extracellular polysaccharide. In addition, carvacrol strongly inhibited the antioxidant pigment staphyloxanthin and its intermediates' synthesis in MRSA. Inhibition of biofilm and staphyloxanthin by carvacrol enhanced the susceptibility of MRSA to oxidants and healthy human blood. Quantitative polymerase chain reaction (qPCR) analysis unveiled the downregulation of sarA-mediated biofilm gene expression and staphyloxanthin-associated crtM gene expression. The sarA-dependent antibiofilm potential of carvacrol was validated using S. aureus Newman wild-type and isogenic ΔsarA strains. In silico molecular docking analysis showed the high binding efficacy of carvacrol with staphylococcal accessory regulator A (SarA) and 4,4'-diapophytoene synthase (CrtM) when compared to positive controls. Furthermore, the in vivo efficacy of carvacrol against MRSA infection was demonstrated using the model organism Galleria mellonella. The results revealed the nontoxic nature of carvacrol to the larvae and the rescuing potential of carvacrol against MRSA infection. Finally, the current study reveals the potential of carvacrol in inhibiting the biofilm formation and staphyloxanthin synthesis of MRSA by targeting the global regulator SarA and a novel antivirulence target CrtM.}, } @article {pmid33324579, year = {2020}, author = {Wall, G and Chen, E and Hull, MV and Lopez-Ribot, JL}, title = {Screening the CALIBR ReFRAME Library in Search for Inhibitors of Candida auris Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {597931}, pmid = {33324579}, issn = {2235-2988}, support = {R21 AI140823/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida ; *Candidiasis/drug therapy ; Humans ; }, abstract = {Candida auris is an emerging yeast which, since its first isolation about a decade ago, has spread rapidly and triggered major infectious outbreaks in health care facilities around the world. C. auris strains often display resistance to clinically-used antifungal agents, contributing to high mortality rates. Thus, there is an urgent need for new antifungals to contain the spread of this emerging multi-drug resistant pathogen and to improve patient outcomes. However, the timeline for the development of a new antifungal agent typically exceeds 10‑15 years. Thus, repurposing of current drugs could significantly accelerate the development and eventual deployment of novel therapies for the treatment of C. auris infections. Toward this end, in this study we have profiled a library of known drugs encompassing approximately 12,000 clinical-stage or FDA-approved small molecules in search for known molecules with antifungal activity against C. auris; more specifically, those capable of inhibiting C. auris biofilm formation. From this library, 100 compounds displaying antifungal activity were identified in the initial screen, including 26 compounds for which a dose-response relationship with biofilm-inhibitory activity against C. auris could be confirmed. Of these, five were identified as the most interesting potential repositionable candidates. Due to their known pharmacological and human safety profiles, identification of such compounds should allow for their accelerated preclinical and clinical development for the treatment of C. auris infections.}, } @article {pmid33324354, year = {2020}, author = {Haque, MM and Mosharaf, MK and Khatun, M and Haque, MA and Biswas, MS and Islam, MS and Islam, MM and Shozib, HB and Miah, MMU and Molla, AH and Siddiquee, MA}, title = {Biofilm Producing Rhizobacteria With Multiple Plant Growth-Promoting Traits Promote Growth of Tomato Under Water-Deficit Stress.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {542053}, pmid = {33324354}, issn = {1664-302X}, abstract = {Plant growth-promoting rhizobacteria (PGPR) not only enhance plant growth but also control phytopathogens and mitigate abiotic stresses, including water-deficit stress. In this study, 21 (26.9%) rhizobacterial strains isolated from drought-prone ecosystems of Bangladesh were able to form air-liquid (AL) biofilms in the glass test tubes containing salt-optimized broth plus glycerol (SOBG) medium. Based on 16S rRNA gene sequencing, Pseudomonas chlororaphis (ESR3 and ESR15), P. azotoformans ESR4, P. poae ESR6, P. fluorescens (ESR7 and ESR25), P. gessardii ESR9, P. cedrina (ESR12, ESR16, and ESR23), P. veronii (ESR13 and ESR21), P. parafulva ESB18, Stenotrophomonas maltophilia ESR20, Bacillus cereus (ESD3, ESD21, and ESB22), B. horikoshii ESD16, B. aryabhattai ESB6, B. megaterium ESB9, and Staphylococcus saprophyticus ESD8 were identified. Fourier transform infrared spectroscopy studies showed that the biofilm matrices contain proteins, polysaccharides, nucleic acids, and lipids. Congo red binding results indicated that these bacteria produced curli fimbriae and nanocellulose-rich polysaccharides. Expression of nanocellulose was also confirmed by Calcofluor binding assays and scanning electron microscopy. In vitro studies revealed that all these rhizobacterial strains expressed multiple plant growth-promoting traits including N2 fixation, production of indole-3-acetic acid, solubilization of nutrients (P, K, and Zn), and production of ammonia, siderophores, ACC deaminase, catalases, lipases, cellulases, and proteases. Several bacteria were also tolerant to multifarious stresses such as drought, high temperature, extreme pH, and salinity. Among these rhizobacteria, P. cedrina ESR12, P. chlororaphis ESR15, and B. cereus ESD3 impeded the growth of Xanthomonas campestris pv. campestris ATCC 33913, while P. chlororaphis ESR15 and B. cereus ESD21 prevented the progression of Ralstonia solanacearum ATCC[®] 11696[TM]. In a pot experiment, tomato plants inoculated with P. azotoformans ESR4, P. poae ESR6, P. gessardii ESR9, P. cedrina ESR12, P. chlororaphis ESR15, S. maltophilia ESR20, P. veronii ESR21, and B. aryabhattai ESB6 exhibited an increased plant growth compared to the non-inoculated plants under water deficit-stressed conditions. Accordingly, the bacterial-treated plants showed a higher antioxidant defense system and a fewer tissue damages than non-inoculated plants under water-limiting conditions. Therefore, biofilm-producing PGPR can be utilized as plant growth promoters, suppressors of plant pathogens, and alleviators of water-deficit stress.}, } @article {pmid33324065, year = {2020}, author = {Dapunt, U and Prior, B and Kretzer, JP and Giese, T and Zhao, Y}, title = {Bacterial Biofilm Components Induce an Enhanced Inflammatory Response Against Metal Wear Particles.}, journal = {Therapeutics and clinical risk management}, volume = {16}, number = {}, pages = {1203-1212}, pmid = {33324065}, issn = {1176-6336}, abstract = {PURPOSE: Aseptic implant loosening is still a feared complication in the field of orthopaedics. Presumably, a chronic inflammatory response is induced by wear particles, which leads to osteoclast generation, bone degradation and hence loosening of the implant. Since it has been demonstrated in the literature that most implants are in fact colonized by bacteria, the question arises whether aseptic implant loosening is truly aseptic. The aim of this study was to investigate a possibly enhanced inflammatory response to metal wear particles in the context of subclinical infection.

PATIENTS AND METHODS: Tissue samples were collected intra-operatively from patients undergoing implant-exchange surgery due to aseptic loosening. Histopathological analysis was performed, as well as gene expression analysis for the pro-inflammatory cytokine Interleukin-8. By a series of in vitro experiments, the effect of metal wear particles on human monocytes, polymorphonuclear neutrophiles and osteoblasts was investigated. Additionally, minor amounts of lipoteichoic acid (LTA) and the bacterial heat shock protein GroEL were added.

RESULTS: Histopathology of tissue samples revealed an accumulation of metal wear particles, as well as a cellular infiltrate consisting predominately of mononuclear cells. Furthermore, high expression of IL-8 could be detected in tissue surrounding the implant. Monocytes and osteoblasts in particular showed an increased release of IL-8 after stimulation with metal wear particles and in particular after stimulation with bacterial components and wear particles together.

CONCLUSION: We were able to show that minor amounts of bacterial components and metal wear particles together induce an enhanced inflammatory response in human monocytes and osteoblasts. This effect could significantly contribute to the generation of bone-resorbing osteoclasts and hence implant-loosening.}, } @article {pmid33322790, year = {2020}, author = {Han, YN and Wei, M and Han, F and Fang, C and Wang, D and Zhong, YJ and Guo, CL and Shi, XY and Xie, ZK and Li, FM}, title = {Greater Biofilm Formation and Increased Biodegradation of Polyethylene Film by a Microbial Consortium of Arthrobacter sp. and Streptomyces sp.}, journal = {Microorganisms}, volume = {8}, number = {12}, pages = {}, pmid = {33322790}, issn = {2076-2607}, support = {31470496//National Natural Science Foundation of China/ ; BP0719040//'111' Programme/ ; }, abstract = {The widespread use of polyethylene (PE) mulch films has led to a significant accumulation of plastic waste in agricultural soils. The biodegradation of plastic waste by microorganisms promises to provide a cost-effective and environmentally-friendly alternative for mitigating soil plastic pollution. A large number of microorganisms capable of degrading PE have been reported, but degradation may be further enhanced by the cooperative activity of multiple microbial species. Here, two novel strains of Arthrobacter sp. and Streptomyces sp. were isolated from agricultural soils and shown to grow with PE film as a sole carbon source. Arthrobacter sp. mainly grew in the suspension phase of the culture, and Streptomyces sp. formed substantial biofilms on the surface of the PE film, indicating that these strains were of different metabolic types and occupied different microenvironments with contrasting nutritional access. Individual strains were able to degrade the PE film to some extent in a 90-day inoculation experiment, as indicated by decreased hydrophobicity, increased carbonyl index and CO2 evolution, and the formation of biofilms on the film surface. However, a consortium of both strains had a much greater effect on these degradation properties. Together, these results provide new insights into the mechanisms of PE biodegradation by a microbial consortium composed of different types of microbes with possible metabolic complementarities.}, } @article {pmid33322639, year = {2020}, author = {Szemerédi, N and Kincses, A and Rehorova, K and Hoang, L and Salardón-Jiménez, N and Sevilla-Hernández, C and Viktorová, J and Domínguez-Álvarez, E and Spengler, G}, title = {Ketone- and Cyano-Selenoesters to Overcome Efflux Pump, Quorum-Sensing, and Biofilm-Mediated Resistance.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33322639}, issn = {2079-6382}, support = {SZTE ÁOK-KKA 2018/270-62-2//University of Szeged/ ; GINOP-2.3.2-15-2016-00038//EU, Hungary/ ; INTER-COST LTC19007//Czech Ministry of Education, Youth and Sports/ ; COST Action CA17104 STRATAGEM//EU/ ; }, abstract = {The emergence of drug-resistant pathogens leads to a gradual decline in the efficacy of many antibacterial agents, which poses a serious problem for proper therapy. Multidrug resistance (MDR) mechanisms allow resistant bacteria to have limited uptake of drugs, modification of their target molecules, drug inactivation, or release of the drug into the extracellular space by efflux pumps (EPs). In previous studies, selenoesters have proved to be promising derivatives with a noteworthy antimicrobial activity. On the basis of these results, two series of novel selenoesters were synthesized to achieve more potent antibacterial activity on Gram-positive and Gram-negative bacteria. Fifteen selenoesters (eight ketone-selenoesters and seven cyano-selenoesters) were investigated with regards to their efflux pump-inhibiting, anti-quorum-sensing (QS), and anti-biofilm effects in vitro. According to the results of the antibacterial activity, the ketone-selenoesters proved to be more potent antibacterial compounds than the cyano-selenoesters. With regard to efflux pump inhibition, one cyano-selenoester on methicillin-resistant S. aureus and one ketone-selenoester on Salmonella Typhimurium were potent inhibitors. The biofilm inhibitory capacity and the ability of the derivatives to disrupt mature biofilms were noteworthy in all the experimental systems applied. Regarding QS inhibition, four ketone-selenoesters and three cyano-selenoesters exerted a noteworthy effect on Vibrio campbellii strains.}, } @article {pmid33322518, year = {2020}, author = {Gomes, IB and Simões, M and Simões, LC}, title = {Copper Surfaces in Biofilm Control.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {10}, number = {12}, pages = {}, pmid = {33322518}, issn = {2079-4991}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219; PTDC/ASP-PES/28397/2017 - POCI-01-0145-FEDER-028397; POCI-01-0247-FEDER-035234//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {Biofilms are structures comprising microorganisms associated to surfaces and enclosed by an extracellular polymeric matrix produced by the colonizer cells. These structures protect microorganisms from adverse environmental conditions. Biofilms are typically associated with several negative impacts for health and industries and no effective strategy for their complete control/eradication has been identified so far. The antimicrobial properties of copper are well recognized among the scientific community, which increased their interest for the use of these materials in different applications. In this review the use of different copper materials (copper, copper alloys, nanoparticles and copper-based coatings) in medical settings, industrial equipment and plumbing systems will be discussed considering their potential to prevent and control biofilm formation. Particular attention is given to the mode of action of copper materials. The putative impact of copper materials in the health and/or products quality is reviewed taking into account their main use and the possible effects on the spread of antimicrobial resistance.}, } @article {pmid33321906, year = {2020}, author = {Casciaro, B and Loffredo, MR and Cappiello, F and Fabiano, G and Torrini, L and Mangoni, ML}, title = {The Antimicrobial Peptide Temporin G: Anti-Biofilm, Anti-Persister Activities, and Potentiator Effect of Tobramycin Efficacy Against Staphylococcus aureus.}, journal = {International journal of molecular sciences}, volume = {21}, number = {24}, pages = {}, pmid = {33321906}, issn = {1422-0067}, support = {RM11916B6A28725C//Sapienza Università di Roma/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Drug Synergism ; Staphylococcus aureus/*drug effects ; Tobramycin/pharmacology ; }, abstract = {Bacterial biofilms are a serious threat for human health, and the Gram-positive bacterium Staphylococcus aureus is one of the microorganisms that can easily switch from a planktonic to a sessile lifestyle, providing protection from a large variety of adverse environmental conditions. Dormant non-dividing cells with low metabolic activity, named persisters, are tolerant to antibiotic treatment and are the principal cause of recalcitrant and resistant infections, including skin infections. Antimicrobial peptides (AMPs) hold promise as new anti-infective agents to treat such infections. Here for the first time, we investigated the activity of the frog-skin AMP temporin G (TG) against preformed S. aureus biofilm including persisters, as well as its efficacy in combination with tobramycin, in inhibiting S. aureus growth. TG was found to provoke ~50 to 100% reduction of biofilm viability in the concentration range from 12.5 to 100 µM vs ATCC and clinical isolates and to be active against persister cells (about 70-80% killing at 50-100 µM). Notably, sub-inhibitory concentrations of TG in combination with tobramycin were able to significantly reduce S. aureus growth, potentiating the antibiotic power. No critical cytotoxicity was detected when TG was tested in vitro up to 100 µM against human keratinocytes, confirming its safety profile for the development of a new potential anti-infective drug, especially for treatment of bacterial skin infections.}, } @article {pmid33321772, year = {2020}, author = {Mello, PL and Riboli, DFM and Martins, LA and Brito, MAVP and Victória, C and Calixto Romero, L and Ribeiro de Souza da Cunha, ML}, title = {Staphylococcus spp. Isolated from Bovine Subclinical Mastitis in Different Regions of Brazil: Molecular Typing and Biofilm Gene Expression Analysis by RT-qPCR.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33321772}, issn = {2079-6382}, support = {2012/24135-0 and 2015/01401-4//State funding agency São Paulo Research Foundation (FAPESP)/ ; 304051/2017-9//National Council for Scientific and Technological Development (CNPq)/ ; }, abstract = {Bovine mastitis is mainly caused by bacteria of the genus Staphylococcus spp., which possess different virulence factors, including the capacity for biofilm formation that provides enhanced protection against the action of immune system components and serves as a barrier against the penetration of antimicrobial agents. This study aimed to characterize 181 Staphylococcus spp. Strains-including Staphylococcusaureus and coagulase-negative staphylococci (CoNS) isolated from bovine subclinical mastitis in six Brazilian states-by molecular methods. RT-qPCR was used to verify the expression of genes of the ica operon-mainly responsible for biofilm formation-as well as bap and bhp. Chromosome similarity among the isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The icaA gene was detected in 79 (43.6%) isolates, icaB in 24 (13.2%), icaC in 57 (31.4%), and icaD in 127 (70.1%). The bap gene was identified in 66 (36.4%) isolates, while the bhp gene was found in nine (4.9%). RT-qPCR confirmed the expression of the icaA gene in 60 (75.9%) isolates, of icaB in six (25%), of icaC in 26 (45.6%), and of icaD in 80 (63%). Clonal typing of the isolates by PFGE permitted the identification of eight Staphylococcusaureus clusters that simultaneously included ≥3 strains, with a similarity of ≥80%. Regarding the other species studied, three clusters were observed for Staphylococcuschromogenes and four clusters for Staphylococcusepidermidis. Only one cluster each was identified for Staphylococcussaprophyticus and Staphylococcussimulans, while the other species did not form any cluster. With respect to MLST, ST126 and ST1 were the prevalent sequence types in S. aureus, while in S.epidermidis all sequence types were different. These results reveal strains with the same evolutionary origin as other isolates, which might cause infections in humans and animals, suggesting their ability to spread between these species.}, } @article {pmid33321650, year = {2021}, author = {Vivero-Lopez, M and Xu, X and Muras, A and Otero, A and Concheiro, A and Gaisford, S and Basit, AW and Alvarez-Lorenzo, C and Goyanes, A}, title = {Anti-biofilm multi drug-loaded 3D printed hearing aids.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {119}, number = {}, pages = {111606}, doi = {10.1016/j.msec.2020.111606}, pmid = {33321650}, issn = {1873-0191}, mesh = {Biofilms ; *Hearing Aids ; Humans ; *Pharmaceutical Preparations ; Printing, Three-Dimensional ; Staphylococcus aureus ; }, abstract = {Over 5% of the world's population has disabling hearing loss, which affects approximately one third of individuals over 65 years. Hearing aids are commonly used in this population group, but prolonged use of these devices may cause ear infections. We describe for the first time, the use of 3D printing to fabricate hearing aids loaded with two antibiotics, ciprofloxacin and fluocinolone acetonide. Digital light processing 3D printing was employed to manufacture hearing aids from two polymer resins, ENG hard and Flexible. The inclusion of the antibiotics did not affect the mechanical properties of the hearing aids. All multi-drug-loaded devices exhibited a hydrophilic surface, excellent blood compatibility and anti-biofilm activity against P. aeruginosa and S. aureus. Hearing aids loaded with ciprofloxacin (6% w/w) and fluocinolone acetonide (0.5% w/w) sustained drug release for more than two weeks and inhibited biofilm formation on the surface of the devices and bacteria growth in the surrounding medium. In summary, this work highlights the potential of vat photopolymerization 3D printing as a versatile manufacturing approach to fabricate high-fidelity patient-specific medical devices with anti-bacterial properties.}, } @article {pmid33321588, year = {2021}, author = {Mishra, P and Gupta, P and Pruthi, V}, title = {Cinnamaldehyde incorporated gellan/PVA electrospun nanofibers for eradicating Candida biofilm.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {119}, number = {}, pages = {111450}, doi = {10.1016/j.msec.2020.111450}, pmid = {33321588}, issn = {1873-0191}, mesh = {Acrolein/analogs & derivatives ; Biofilms ; Candida ; Humans ; *Nanofibers ; Polysaccharides, Bacterial ; *Polyvinyl Alcohol ; }, abstract = {Immunocompromised patients encounter fungal infections more frequently than healthy individuals. Conventional drugs associated health risk and resistance, portrayed fungal infections as a global health problem. This issue needs to be answered immediately by designing a novel anti-fungal therapeutic agent. Phytoactive molecules based therapeutics are most suitable candidate due to their low cytotoxicity and minimal side effects to the host. In this study, cinnamaldehyde (CA), an FDA approved phytoactive molecule present in cinnamon essential oil was incorporated into gellan (GA)/poly vinyl alcohol (PVA) based electrospun nanofibers to resolve the issues like low water solubility, high volatility and irritant effect associated with CA and also to enhance its therapeutic applications. The drug encapsulation, morphology and physical properties of the synthesized CA nanofibers were evaluated by FESEM, AFM, TGA, FTIR and static water contact angle analysis. The average diameters of CA encapsulated GA/PVA nanofibers and GA/PVA nanofibers were recorded to be 278.5 ± 57.8 nm and 204.03 ± 39.14 nm, respectively. These nanofibers were evaluated for their anti-biofilm activity against Candida using XTT (2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-2H-tetrazolium salt) reduction assay. Data demonstrated that CA encapsulated GA/PVA nanofibers can effectively eradicate 89.29% and 50.45% of Candida glabrata and Candida albicans biofilm respectively. CA encapsulated nanofibers exhibited brilliant antimicrobial property against Staphylococcus aureus and Pseudomonas aeruginosa. The cytotoxicity assay demonstrated that nanofibers loaded with CA have anticancer properties as it reduces cell viability of breast cancer cells (MCF-7) by 27.7%. These CA loaded GA/PVA (CA-GA/PVA) nanofibers could be used as novel wound dressing material and coatings on biomedical implants to eradicate biofilm.}, } @article {pmid33321571, year = {2020}, author = {Gonçalves, NL and Borges, VM and de Arruda, JAA and Dos Santos, EG and Diniz, IMA and Madeira, MFM and Moreno, A}, title = {Antimicrobial effects of photodynamic therapy on Staphylococcus aureus biofilm grown on a specific acrylic resin surface for ocular prostheses.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {32}, number = {}, pages = {102042}, doi = {10.1016/j.pdpdt.2020.102042}, pmid = {33321571}, issn = {1873-1597}, mesh = {Acrylic Resins ; *Anti-Infective Agents ; Biofilms ; Eye, Artificial ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; *Staphylococcus aureus ; }, abstract = {BACKGROUND: Photodynamic therapy (PDT) is a treatment for the specific control of oral biofilms. However, its effects on maxillofacial prostheses have been barely explored. In this study, we evaluated the antimicrobial effect of PDT using methylene blue (MB) and laser against a Staphylococcus aureus biofilm developed on the surface of scleral acrylic resin.

METHODS: Sixty-six specimens of acrylic resin designed for ocular prostheses were fabricated in a disk-shaped format (3 × 10 mm). S. aureus biofilm was grown on the surface of the specimens for 24 h and the disks were then treated with MB at different concentrations (25, 50, 75 or 100 μg/mL), with or without PDT (GaAlAs diode laser; 660 nm; 100 mW; 9 J; 321.4 J.cm[-2]; 3.5 W.cm[-2] and 90 s). Control groups were treated with 2% chlorhexidine gluconate (CHX) or phosphate buffered saline. After the treatments, colony forming units (CFU) were counted and the samples were qualitatively evaluated by scanning electron microscopy (SEM). Data were analyzed descriptively and by nested ANOVA and the Tukey test (α = .05).

RESULTS: PDT groups with MB concentrations at 75 and 100 μg/mL formed fewer CFU compared to the other groups (P < 0.001) and the 2% CHX group did not form any CFU. SEM images revealed that the surface of the polymers in these groups did not show bacterial colonies.

CONCLUSIONS: PDT significantly reduced S. aureus biofilm in the scleral acrylic resin when associated with an MB dilution of 75 μg/mL or higher. Thus, PDT can be a promising candidate for disinfecting ocular prostheses.}, } @article {pmid33319980, year = {2020}, author = {Chandankere, R and Ravikumar, Y and Zabed, HM and Sabapathy, PC and Yun, J and Zhang, G and Qi, X}, title = {Conversion of Agroindustrial Wastes to Rhamnolipid by Enterobacter sp. UJS-RC and Its Role against Biofilm-Forming Foodborne Pathogens.}, journal = {Journal of agricultural and food chemistry}, volume = {68}, number = {52}, pages = {15478-15489}, doi = {10.1021/acs.jafc.0c05028}, pmid = {33319980}, issn = {1520-5118}, mesh = {Agriculture ; Biofilms/*drug effects ; Biotransformation ; Enterobacter/chemistry/*metabolism ; Glycolipids/chemistry/*metabolism/*pharmacology ; Molasses/analysis ; Saccharum/metabolism/microbiology ; Staphylococcus aureus/*drug effects/physiology ; Surface-Active Agents/chemistry/*metabolism ; Waste Products/analysis ; Water Microbiology ; Zea mays/metabolism/microbiology ; }, abstract = {Rhamnolipid is the main group of biosurfactants predominantly produced by Pseudomonas aeruginosa, a ubiquitous and opportunistic pathogen, which limits its large-scale exploitation. Thus, cost-effective rhamnolipid production from a newly isolated nonpathogenic Enterobacter sp. UJS-RC was investigated. The highest rhamnolipid production (4.4 ± 0.2 g/L) was achieved in a medium constituting agroindustrial wastes (sugarcane molasses and corn steep liquor) as substrates. Rhamnolipid exhibited reduced surface tension to 72-28 mN/m with an emulsification index of 75%. The structural analyses demonstrated the presence of methoxyl, carboxyl, and hydroxyl groups in rhamnolipid. Mass spectra indicated eight rhamnolipid congeners, where dirhamnolipid (m/z 650.01) was the dominant congener. Rhamnolipid inhibited biofilm formation of Staphylococcus aureus in a dose-dependent manner, supported by scanning electron microscopy disclosing the disruption of the microcolony/exopolysaccharide matrix. Rhamnolipid's ability to generate reactive oxygen species has thrown light on the mechanism through which the killing of test bacteria may occur.}, } @article {pmid33316854, year = {2021}, author = {Zhang, Z and Zeng, J and Zhou, X and Xu, Q and Li, C and Liu, Y and Zhang, C and Wang, L and Zeng, W and Li, Y}, title = {Activity of Ligustrum robustum (Roxb.) Blume extract against the biofilm formation and exopolysaccharide synthesis of Streptococcus mutans.}, journal = {Molecular oral microbiology}, volume = {36}, number = {1}, pages = {67-79}, doi = {10.1111/omi.12328}, pmid = {33316854}, issn = {2041-1014}, mesh = {Animals ; Biofilms ; Cattle ; *Dental Caries/prevention & control ; Humans ; *Ligustrum ; Plant Extracts/pharmacology ; Streptococcus mutans ; }, abstract = {Ligustrum robustum (Roxb.) Blume is utilized as a traditional Chinese herbal tea with various health benefits and protective effects. Streptococcus mutans is an important cariogenic oral bacteria species. The present study aimed to assess the influence of Ligustrum robustum extract (LRE) on the biofilm formation of S. mutans and the mechanism of its action, as well as to identify its chemical components. For chemical identification, HPLC-MS and nuclear magnetic resonance were applied and four identified phytochemicals were reported (Ligurobustoside B, Ligurobustoside N, Ligurobustoside J, and Ligurobustoside C). The dose-dependent (0.5 to 2.0 μg/μL) antimicrobial toxicity of LRE against S. mutans biofilm formation and exopolysaccharide (EPS) synthesis was evaluated by confocal laser scanning microscopy (CLSM), Crystal violet stain, and CFU counting. The microstructure of S. mutans biofilm treated with LRE was investigated both on glass coverslips and ex vivo bovine dental enamel by scanning electron microscopy (SEM). Moreover, LRE downregulated the expression of S. mutans glucosyltransferase-encoding genes gtfB, gtfC, and gtfD, and the quorum sensing (QS) factors comD and comE, suggesting its toxic mechanism. In addition, the result of CCK-8 test on human oral cells revealed an acceptable biocompatibility of LRE. These findings indicated the possible application of this daily consumed herbal tea for caries prevention.}, } @article {pmid33316516, year = {2021}, author = {Tian, L and Wang, L}, title = {Multi-omics analysis reveals structure and function of biofilm microbial communities in a pre-denitrification biofilter.}, journal = {The Science of the total environment}, volume = {757}, number = {}, pages = {143908}, doi = {10.1016/j.scitotenv.2020.143908}, pmid = {33316516}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; China ; *Denitrification ; *Microbiota ; Nitrogen ; Wastewater ; }, abstract = {The highly complex microbial communities in biofilm play crucial roles in the pollutant removal performance of wastewater treatment plants (WWTPs). In the present study, using multi-omics analysis, we studied microbial structure, key enzymes, functional traits, and key metabolic pathways of pre-denitrification biofilter in an urban WWTP in China. The analysis results of metagenomic and metaproteomic showed that Betaproteobacteria and Flavobacteriia were dominant in biofilms. The integrated metagenomic and metaproteomic data showed that the expression of nitrogen metabolism genes was high, and the high proportion of denitrification module indicating that denitrification was the main nitrogen removal pathway. The most abundant denitrifying bacterial genera were: Dechloromonas, Acidovorax, Bosea, Polaromonas, and Chryseobacterium. And microorganisms with denitrification potential may not be able to denitrify in the actual operation of the filter. The integrated analysis of metaproteomic and metabolomic showed that there was a correlation between biofilm microorganisms and metabolites. Metabolomic analysis indicated that metabolic profiles of biofilms varied with layer height. This study provides the first detailed microbial communities and metabolic profiles in a full-scale pre-denitrification biofilter and clarifies the mechanism of denitrification.}, } @article {pmid33316497, year = {2021}, author = {Valdés, ME and Santos, LHMLM and Rodríguez Castro, MC and Giorgi, A and Barceló, D and Rodríguez-Mozaz, S and Amé, MV}, title = {Distribution of antibiotics in water, sediments and biofilm in an urban river (Córdoba, Argentina, LA).}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {269}, number = {}, pages = {116133}, doi = {10.1016/j.envpol.2020.116133}, pmid = {33316497}, issn = {1873-6424}, mesh = {*Anti-Bacterial Agents/analysis ; Argentina ; Biofilms ; China ; Ecosystem ; Environmental Monitoring ; Geologic Sediments ; Humans ; Tandem Mass Spectrometry ; Water ; *Water Pollutants, Chemical/analysis ; }, abstract = {In this study, we evaluated the distribution of up to forty-three antibiotics and 4 metabolites residues in different environmental compartments of an urban river receiving both diffuse and point sources of pollution. This is the first study to assess the fate of different antibiotic families in water, biofilms and sediments simultaneously under a real urban river scenario. Solid phase extraction, bead-beating disruption and pressurized liquid extraction were applied for sample preparation of water, biofilm and sediment respectively, followed by the quantification of target antibiotics by UPLC-ESI-MS/MS. Twelve antibiotics belonging to eight chemical families were detected in Suquía River samples (67% positive samples). Sites downstream the WWTP discharge were the most polluted ones. Concentrations of positive samples ranged 0.003-0.29 µg L[-1] in water (max. cephalexin), 2-652 µg kg[-1]d.w. in biofilm (max. ciprofloxacin) and 2-34 µg kg[-1]d.w. in sediment (max. ofloxacin). Fluoroquinolones, macrolides and trimethoprim were the most frequently detected antibiotics in the three compartments. However cephalexin was the prevalent antibiotic in water. Antibiotics exhibited preference for their accumulation from water into biofilms rather than in sediments (bioaccumulation factors > 1,000 L kg[-1]d.w. in biofilms, while pseudo-partition coefficients in sediments < 1,000 L kg[-1]d.w.). Downstream the WWTP there was an association of antibiotics levels in biofilms with ash-free dry weight, opposite to chlorophyll-a (indicative of heterotrophic communities). Cephalexin and clarithromycin in river water were found to pose high risk for the aquatic ecosystem, while ciprofloxacin presented high risk for development of antimicrobial resistance. This study contributes to the understanding of the fate and distribution of antibiotic pollution in urban rivers, reveals biofilm accumulation as an important environmental fate, and calls for attention to government authorities to manage identified highly risk antibiotics.}, } @article {pmid33314723, year = {2021}, author = {Alves, PJ and Barreto, RT and Barrois, BM and Gryson, LG and Meaume, S and Monstrey, SJ}, title = {Update on the role of antiseptics in the management of chronic wounds with critical colonisation and/or biofilm.}, journal = {International wound journal}, volume = {18}, number = {3}, pages = {342-358}, pmid = {33314723}, issn = {1742-481X}, mesh = {*Anti-Infective Agents, Local ; *Bacterial Infections ; Biofilms ; Humans ; Povidone-Iodine ; Wound Healing ; *Wound Infection ; }, abstract = {Biofilms play a major role in delaying chronic wounds from healing. A wound infiltrated with biofilm, or "critically colonised" wound, may become clinically infected if the number of microbes exceeds a critical level. Chronic wound biofilms represent a significant treatment challenge by demonstrating recalcitrance towards antimicrobial agents. However, a "window of opportunity" may exist after wound debridement when biofilms are more susceptible to topical antiseptics. Here, we discuss the role of antiseptics in the management of chronic wounds and biofilm, focusing on povidone-iodine (PVP-I) in comparison with two commonly used antiseptics: polyhexanide (PHMB) and silver. This article is based on the literature reviewed during a focus group meeting on antiseptics in wound care and biofilm management, and on a PubMed search conducted in March 2020. Compared with PHMB and silver, PVP-I has a broader spectrum of antimicrobial activity, potent antibiofilm efficacy, no acquired bacterial resistance or cross-resistance, low cytotoxicity, good tolerability, and an ability to promote wound healing. PVP-I represents a viable therapeutic option in wound care and biofilm management, with the potential to treat biofilm-infiltrated, critically colonised wounds. We propose a practical algorithm to guide the management of chronic, non-healing wounds due to critical colonisation or biofilm, using PVP-I.}, } @article {pmid33314618, year = {2021}, author = {Peng, J and Schachterle, JK and Sundin, GW}, title = {Orchestration of virulence factor expression and modulation of biofilm dispersal in Erwinia amylovora through activation of the Hfq-dependent small RNA RprA.}, journal = {Molecular plant pathology}, volume = {22}, number = {2}, pages = {255-270}, pmid = {33314618}, issn = {1364-3703}, mesh = {Biofilms ; Cellulose/genetics ; Erwinia amylovora/genetics/*metabolism/pathogenicity ; Hexosyltransferases/genetics ; Movement ; Polysaccharides, Bacterial/genetics ; Promoter Regions, Genetic ; RNA, Bacterial/*physiology ; Type III Secretion Systems/genetics ; Virulence Factors/genetics/*metabolism ; }, abstract = {Erwinia amylovora is the causative agent of the devastating disease fire blight of pome fruit trees. After infection of host plant leaves at apple shoot tips, E. amylovora cells form biofilms in xylem vessels, restrict water flow, and cause wilting symptoms. Although E. amylovora is well known to be able to cause systemic infection, how biofilm cells of E. amylovora transit from the sessile mode of growth in xylem to the planktonic mode of growth in cortical parenchyma remains unknown. Increasing evidence has suggested the important modulatory roles of Hfq-dependent small RNAs (sRNAs) in the pathogenesis of E. amylovora. Here, we demonstrate that the sRNA RprA acts as a positive regulator of amylovoran exopolysaccharide production, the type III secretion system (T3SS), and flagellar-dependent motility, and as a negative regulator of levansucrase activity and cellulose production. We also show that RprA affects the promoter activity of multiple virulence factor genes and regulates hrpS, a critical T3SS regulator, at the posttranscriptional level. We determined that rprA expression can be activated by the Rcs phosphorelay, and that expression is active during T3SS-mediated host infection in an immature pear fruit infection model. We further showed that overexpression of rprA activated the in vitro dispersal of E. amylovora cells from biofilms. Thus, our investigation of the varied role of RprA in affecting E. amylovora virulence provides important insights into the functions of this sRNA in biofilm control and systemic infection.}, } @article {pmid33311010, year = {2020}, author = {Mokeem, LS and Willis, LH and Windsor, LJ and Cook, NB and Eckert, G and Gregory, RL}, title = {Combined effects of soft drinks and nicotine on Streptococcus mutans metabolic activity and biofilm formation.}, journal = {Journal of oral science}, volume = {63}, number = {1}, pages = {75-78}, doi = {10.2334/josnusd.20-0073}, pmid = {33311010}, issn = {1880-4926}, mesh = {Biofilms ; Carbonated Beverages/adverse effects ; *Dental Caries ; Humans ; Nicotine ; *Streptococcus mutans ; }, abstract = {The purpose of this study was to explore the effects of nicotine on the activity of Streptococcus mutans (S. mutans) in soft drinks. Regular soft drinks contain large proportions of high-fructose corn syrup (HFCS), which increases the activity of S. mutans resulting in high-caries risk compared with sugar-free soft drinks. Nicotine use exhibits a strong correlation with increased S. mutans biofilm formation. The soft drinks chosen were (Coca-Cola Classic, Diet Coke, Coca-Cola Zero Sugar, Caffeine-Free Coca-Cola, Caffeine-Free Diet Coke, Caffeine-Free Coca-Cola Zero Sugar). S. mutans was grown overnight in tryptic soy broth; nicotine was diluted in tryptic soy broth supplemented with 1.0% sucrose followed by soft drinks in dilution of 1:3. Total growth absorbance and biofilm growth were determined by spectrophotometry, absorbance measured to determine biofilm formation, and metabolic activity quantified. One-way ANOVA showed a considerable effect for HFCS and caffeine in the presence of nicotine and their interaction in all measures. Results showed sugar-free caffeinated colas demonstrated significant effect in inhibiting S. mutans biofilm formation and metabolic activity with nicotine. Nicotine-induced S. mutans increased biofilm formation and metabolic activity in the presence of HFCS and caffeine in soft drinks. In conclusion, smokers should consider sugar-free caffeinated versions to minimize the chance of developing dental caries dut to the reduction of biofilm formation.}, } @article {pmid33310711, year = {2021}, author = {Xia, Y and Xu, C and Wang, D and Weng, Y and Jin, Y and Bai, F and Cheng, Z and Kuipers, OP and Wu, W}, title = {YbeY controls the type III and type VI secretion systems and biofilm formation through RetS in Pseudomonas aeruginosa.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {5}, pages = {}, pmid = {33310711}, issn = {1098-5336}, abstract = {YbeY is a highly conserved RNase in bacteria and plays essential roles in the maturation of 16S rRNA, regulation of small RNAs (sRNAs) and bacterial responses to environmental stresses. Previously, we verified the role of YbeY in rRNA processing and ribosome maturation in Pseudomonas aeruginosa and demonstrated YbeY-mediated regulation of rpoS through a sRNA ReaL. In this study, we demonstrate that mutation of the ybeY gene results in upregulation of the type III secretion system (T3SS) genes as well as downregulation of the type VI secretion system (T6SS) genes and reduction of biofilm formation. By examining the expression of the known sRNAs in P. aeruginosa, we found that mutation of the ybeY gene leads to downregulation of the small RNAs RsmY/Z that control the T3SS, the T6SS and biofilm formation. Further studies revealed that the reduced levels of RsmY/Z are due to upregulation of retS Taken together, our results reveal the pleiotropic functions of YbeY and provide detailed mechanisms of YbeY-mediated regulation in P. aeruginosa IMPORTANCE Pseudomonas aeruginosa causes a variety of acute and chronic infections in humans. The type III secretion system (T3SS) plays an important role in acute infection and the type VI secretion system (T6SS) and biofilm formation are associated with chronic infections. Understanding of the mechanisms that control the virulence determinants involved in acute and chronic infections will provide clues for the development of effective treatment strategies. Our results reveal a novel RNase mediated regulation on the T3SS, T6SS and biofilm formation in P. aeruginosa.}, } @article {pmid33308162, year = {2020}, author = {Maes, S and De Reu, K and Van Weyenberg, S and Lories, B and Heyndrickx, M and Steenackers, H}, title = {Pseudomonas putida as a potential biocontrol agent against Salmonella Java biofilm formation in the drinking water system of broiler houses.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {373}, pmid = {33308162}, issn = {1471-2180}, support = {CELSA/18/031//Onderzoeksraad, KU Leuven/ ; C24/18/046//Onderzoeksraad, KU Leuven/ ; }, mesh = {Animal Husbandry ; Animals ; Biofilms/*growth & development ; *Biological Control Agents ; Chickens ; Drinking Water/*microbiology ; Indonesia ; Microbial Interactions ; Pseudomonas putida/*physiology ; Salmonella/*physiology ; }, abstract = {BACKGROUND: Environmental biofilms can induce attachment and protection of other microorganisms including pathogens, but can also prevent them from invasion and colonization. This opens the possibility for so-called biocontrol strategies, wherein microorganisms are applied to control the presence of other microbes. The potential for both positive and negative interactions between microbes, however, raises the need for in depth characterization of the sociobiology of candidate biocontrol agents (BCAs). The inside of the drinking water system (DWS) of broiler houses is an interesting niche to apply BCAs, because contamination of these systems with pathogens plays an important role in the infection of broiler chickens and consequently humans. In this study, Pseudomonas putida, which is part of the natural microbiota in the DWS of broiler houses, was evaluated as BCA against the broiler pathogen Salmonella Java.

RESULTS: To study the interaction between these species, an in vitro model was developed simulating biofilm formation in the drinking water system of broilers. Dual-species biofilms of P. putida strains P1, P2, and P3 with S. Java were characterized by competitive interactions, independent of P. putida strain, S. Java inoculum density and application order. When equal inocula of S. Java and P. putida strains P1 or P3 were simultaneously applied, the interaction was characterized by mutual inhibition, whereas P. putida strain P2 showed an exploitation of S. Java. Lowering the inoculum density of S. Java changed the interaction with P. putida strain P3 also into an exploitation of S. Java. A further increase in S. Java inhibition was established by P. putida strain P3 forming a mature biofilm before applying S. Java.

CONCLUSIONS: This study provides the first results showing the potential of P. putida as BCA against S. Java in the broiler environment. Future work should include more complex microbial communities residing in the DWS, additional Salmonella strains as well as chemicals typically used to clean and disinfect the system.}, } @article {pmid33308025, year = {2022}, author = {Olsheimer, D and la Cour Jansen, J and Gustavsson, DJI}, title = {Ex-situ manometric activity test for evaluation of mainstream anammox in Moving Bed Biofilm Reactors.}, journal = {Environmental technology}, volume = {43}, number = {13}, pages = {1980-1987}, doi = {10.1080/09593330.2020.1864023}, pmid = {33308025}, issn = {1479-487X}, mesh = {*Ammonium Compounds ; Anaerobic Ammonia Oxidation ; Anaerobiosis ; Biofilms ; Bioreactors ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater ; }, abstract = {Implementing anammox based processes in the mainstream at municipal wastewater treatment plants is challenging and requires carefully constructed control strategies in order to be successful. A method to measure the specific anammox activity was further developed and implemented in the mainstream anammox pilot plant at Sjölunda Wastewater Treatment Plant. The method was found to be reliable and reproducible. The influence of initial nitrite and ammonium concentrations on the activity as well as temperature dependency were analysed. The continuously monitored manometric batch tests were performed on Moving Bed Biofilm Reactor carriers type K1[®]. The activity showed a dependency of initial nitrite concentrations below 75 mg N L[-1] whereas the activity was independent of initial nitrite concentrations in the interval of 75-125 mg N L[-1]. Temperature dependency of the specific anammox activity as expressed in activation energy Ea increased at lower temperatures (10-20°C) compared to higher temperatures (20-30°C). Decreasing temperature from 30°C to 10°C resulted in 95-98% loss of the anammox activity.}, } @article {pmid33307275, year = {2021}, author = {Kaneko, H and Nakaminami, H and Ozawa, K and Wajima, T and Noguchi, N}, title = {In vitro anti-biofilm effect of anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) agents against the USA300 clone.}, journal = {Journal of global antimicrobial resistance}, volume = {24}, number = {}, pages = {63-71}, doi = {10.1016/j.jgar.2020.11.026}, pmid = {33307275}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Clone Cells ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Staphylococcus aureus ; }, abstract = {OBJECTIVES: Infection with a typical community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), the USA300 clone, has become a worldwide epidemic. Biofilm formation at the site of infection is one of the reasons for the development of intractable infectious diseases resulting from this clone. Here we evaluated the in vitro antibiofilm effects of anti-MRSA agents to identify the most effective agent against the USA300 clone embedded in biofilms.

METHODS: Vancomycin, linezolid, teicoplanin, daptomycin, arbekacin and tigecycline were used as anti-MRSA agents. The biofilm permeability of the anti-MRSA agents was assessed using a biofilm-coated Transwell®. Morphological and compositional effects of anti-MRSA agents against biofilms were analysed based on the distribution of fluorescence intensity using confocal laser microscopy. Bactericidal activities of the anti-MRSA agents against biofilm-embedded S. aureus were compared.

RESULTS: The permeability rates of linezolid (93.1%), daptomycin (91.3%), arbekacin (87.1%) and tigecycline (99.7%) for biofilms formed by the USA300 clone were found to be significantly higher than those of vancomycin (64.9%) and teicoplanin (62.3%) (P < 0.01). Confocal microscopic analysis showed that daptomycin greatly altered the biofilm morphology (decreased thickness and increased roughness) and markedly reduced the area occupied by the biofilm. Furthermore, daptomycin effectively reduced the extracellular DNA of biofilms and showed the highest bactericidal activity against biofilm-embedded USA300 clone among the anti-MRSA agents.

CONCLUSION: The findings from this study demonstrate that, of the tested anti-MRSA agents, daptomycin is the most effective against biofilm-embedded USA300 clone in vitro.}, } @article {pmid33306397, year = {2021}, author = {Kumari, N and Kumar, S and Karmacharya, M and Dubbu, S and Kwon, T and Singh, V and Chae, KH and Kumar, A and Cho, YK and Lee, IS}, title = {Surface-Textured Mixed-Metal-Oxide Nanocrystals as Efficient Catalysts for ROS Production and Biofilm Eradication.}, journal = {Nano letters}, volume = {21}, number = {1}, pages = {279-287}, doi = {10.1021/acs.nanolett.0c03639}, pmid = {33306397}, issn = {1530-6992}, mesh = {*Anti-Infective Agents ; Biofilms ; *Metal Nanoparticles ; Oxides ; Reactive Oxygen Species ; }, abstract = {Next-generation catalysts are urgently needed to tackle the global challenge of antimicrobial resistance. Existing antimicrobials cannot function in the complex and stressful chemical conditions found in biofilms, and as a result, they are unable to infiltrate, diffuse into, and eradicate the biofilm and its associated matrix. Here, we introduce mixed-FeCo-oxide-based surface-textured nanostructures (MTex) as highly efficient magneto-catalytic platforms. These systems can produce defensive ROS over a broad pH range and can effectively diffuse into the biofilm and kill the embedded bacteria. Because the nanostructures are magnetic, biofilm debris can be scraped out of the microchannels. The key antifouling efficacy of MTex originates from the unique surface topography that resembles that of a ploughed field. These are captured as stable textured intermediates during the oxidative annealing and solid-state conversion of β-FeOOH nanocrystals. These nanoscale surfaces will advance progress toward developing a broad array of new enzyme-like properties at the nanobio interface.}, } @article {pmid33305986, year = {2021}, author = {Krishna, D and Dhanashree, B}, title = {Antibiogram, Virulence Genes, and Biofilm-Forming Ability of Clinical Salmonella enterica Serovars: An In Vitro Study.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {7}, pages = {871-878}, doi = {10.1089/mdr.2020.0419}, pmid = {33305986}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Carbon-Oxygen Lyases/genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Salmonella enterica/*drug effects/*genetics ; Salmonella paratyphi A/genetics ; Salmonella typhi/genetics ; Serogroup ; Virulence ; }, abstract = {Salmonella enterica serovar Typhi and Salmonella Paratyphi are causative agents of enteric fever. Salmonella Typhi persists as a biofilm on gallstones. Hence, we studied the biofilm formation, antibiogram, and virulence genes of S. enterica serovars. Antibiogram of S. enterica serovars from human blood and stool samples were studied by Kirby-Bauer disk diffusion method and biofilm by microtiter plate method. We studied the minimum inhibitory concentration of the isolates by Vitek-2 semiautomated system. Polymerase chain reaction was done to detect invA and spvC genes. Of the 55 isolates studied, 36 (65.45%) were Salmonella Typhi, 13 (23.63%) were Salmonella Paratyphi A, 2 (3.64%) were Salmonella Typhimurium, and 4 (7.28%) were Salmonella spp. Resistance to ciprofloxacin and nalidixic acid were found to be 81.8% and 92.7%, respectively. Chloramphenicol and cotrimoxazole-susceptible strains were 98.18%. One each of Salmonella Typhi, Salmonella Paratyphi A, and S. enterica isolates formed weak biofilm at 28°C. However, at 37°C eight Salmonella Typhi produced weak biofilm in the presence of bile. One Salmonella Paratyphi A and two Salmonella spp. formed weak biofilm in the absence of bile. All the isolates had the invA gene. Salmonella Typhimurium had invA and spvC genes. Bile may contribute to biofilm formation and persistence of the Salmonella Typhi on gallstones, which may lead to carrier state. Changing antibiotic susceptibility pattern of Salmonella serovars is observed in our geographic area. The presence of invA and spvC genes indicate the ability of invasiveness and intracellular survival.}, } @article {pmid33305821, year = {2021}, author = {Leininger, A and Yates, MD and Ramirez, M and Kjellerup, B}, title = {Biofilm structure, dynamics, and ecology of an upscaled biocathode wastewater microbial fuel cell.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {3}, pages = {1305-1316}, doi = {10.1002/bit.27653}, pmid = {33305821}, issn = {1097-0290}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Electrodes ; *Microbiota ; Wastewater/*microbiology ; }, abstract = {A microbial fuel cell (MFC) system containing modular half-submerged biocathode was operated for 6 months in an 800 L flow-through system with domestic wastewater. For the first time, spatial and temporal differences in biofilm communities were examined on large three-dimensional electrodes in a wastewater MFC. Biocathode microbial community analysis showed a specialized biofilm community with electrogenic and electrotrophic taxa forming during operation, suggesting potentially opposing electrode reactions. The anodic community structure shifted during operation, but no spatial differences were observed along the length of the electrode. Power output from the system was most strongly influenced by pH. Higher power densities were associated with the use of solids-dewatering filtrate with increased organic matter, conductivity, and pH. The results show that the biocathode was the rate-limiting step and that future MFC design should consider the effect of size, shape, and orientation of biocathodes on their community assembly and electrotrophic ability.}, } @article {pmid33305284, year = {2020}, author = {Kim, HJ and Lee, JH and Ahn, DU and Paik, HD}, title = {Anti-Biofilm Effect of Egg Yolk Phosvitin by Inhibition of Biomass Production and Adherence Activity against Streptococcus mutans.}, journal = {Food science of animal resources}, volume = {40}, number = {6}, pages = {1001-1013}, pmid = {33305284}, issn = {2636-0780}, abstract = {The formation of biofilms on the enamel surface of teeth by Streptococcus mutans is an important step in dental plaque formation, demineralization, and early caries because the biofilm is where other bacteria involved in dental caries attach, grow, and proliferate. The objectives of this study were to determine the effect of phosvitin (PSV) on the biofilm formation, exopolysaccharides (EPS) production, adherence activity of S. mutans, and the expression of genes related to the compounds essential for biofilm formation (quorum-sensing inducers and components of biofilm matrix) by S. mutans. PSV significantly reduced the biofilm-forming activity of S. mutans and increased the degradation of preformed biofilms by S. mutans. PSV inhibited the adherence activity of S. mutans by 31.9%-33.6%, and the production of EPS by 62%-65% depending upon the strains and the amount of PSV added. The expressions of genes regulating the production of EPS and the quorum-sensing-inducers (gtfA, gtfD, ftf, relA, vicR, brpA, and comDE) in all S. mutans strains were down-regulated by PSV, but gtfB was down-regulated only in S. mutans KCTC 5316. Therefore, the anti-biofilm-forming activity of PSV was accomplished through the inhibition of biofilm formation, adherence activity, and the production of quorum-sensing inducers and EPS by S. mutans.}, } @article {pmid33304322, year = {2020}, author = {Wang, L and Zhang, K and Zhang, K and Zhang, J and Fu, J and Li, J and Wang, G and Qiu, Z and Wang, X and Li, J}, title = {Antibacterial Activity of Cinnamomum camphora Essential Oil on Escherichia coli During Planktonic Growth and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {561002}, pmid = {33304322}, issn = {1664-302X}, abstract = {Bacterial biofilms are believed to be principal virulence factors for many localized chronic infectious diseases. Escherichia coli is one of the most common microbial pathogens and frequently causes biofilm-associated opportunistic infections, such as diarrhea, endometritis and mastitis. Cinnamomum camphora essential oil (CCEO) has shown potential in treating intractable chronic endometritis in dairy cows. There is little scientific evidence regarding the effect of CCEO on bacterial biofilms. The objective of this study was to investigate the effect of CCEO on E. coli biofilm formation and how CCEO affects E. coli in suspension and in a biofilm. CCEO killed all clinical E. coli strains in either planktonic or biofilm state isolated from dairy cows with clinical endometritis. The minimum inhibitory concentration (MIC) for 90% of the organisms was 4.297 μL/mL, the minimum bactericidal concentration for 90% of the organisms was 6.378 μL/mL, the minimum biofilm inhibitory concentration for 90% of the organisms was 6.850 μL/mL, and the minimum biofilm eradication concentration (MBEC) for 90% of the organisms was 8.467 μL/mL. The MBECs were generally two times higher than the MICs. Flow cytometry analysis confirmed that significant bacterial killing occurred during the first 1 h after exposure to subinhibitory concentrations of CCEO. In addition, CCEO exerted a significant inhibitory effect on E. coli biofilm formation, and bacterial killing occurred during the first 30 min of exposure to subinhibitory biofilm concentrations of CCEO. The biofilm yield of E. coli was significantly reduced after CCEO treatment, along with an increased dead/live microbial ratio in biofilms compared with that in the non-treated control, as confirmed by scanning electron microscopy images and confocal laser scanning microscopy images. These data revealed that CCEO efficiently kills E. coli during planktonic growth and biofilm formation.}, } @article {pmid33304149, year = {2020}, author = {Alotaibi, GF}, title = {Occurrence of Potentially Pathogenic Bacteria in Epilithic Biofilm Forming Bacteria isolated from Porter Brook River-stones, Sheffield, UK.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {12}, pages = {3405-3414}, pmid = {33304149}, issn = {1319-562X}, abstract = {Biofilms in aquatic ecosystems develop on wet benthic surfaces and are primarily comprised of various allochthonous microorganisms, including bacteria embedded within a self-produced matrix of extracellular polymeric substances (EPS). In such environment, where there is a continuous flow of water, attachment of microbes to surfaces prevents cells being washed out of a suitable habitat with the added benefits of the water flow and the surface itself providing nutrients for growth of attached cells. When watercourses are contaminated with pathogenic bacteria, these can become incorporated into biofilms. This study aimed to isolate and identify the bacterial species within biofilms retrieved from river-stones found in the Porter Brook, Sheffield based on morphological, biochemical characteristics and molecular characteristics, such as 16S rDNA sequence phylogeny analysis. Twenty-two bacterial species were identified. Among these were 10 gram-negative pathogenic bacteria, establishing that potential human pathogens were present within the biofilms. Klebsiella pneumoniae MBB9 isolate showed the greatest ability to form a biofilm using a microtiter plate-based crystal violet assay. Biofilm by K. pneumoniae MBB9 formed rapidly (within 6 h) under static conditions at 37 °C and then increased up to 24 h of incubation before decreasing with further incubation (48 h), whereas the applied shear forces (horizontal orbital shaker; diameter of 25 mm at 150 rpm) had no effect on K. pneumoniae MBB9 biofilm formation.}, } @article {pmid33303927, year = {2020}, author = {Anda, D and Szabó, A and Kovács-Bodor, P and Makk, J and Felföldi, T and Ács, É and Mádl-Szőnyi, J and Borsodi, AK}, title = {In situ modelling of biofilm formation in a hydrothermal spring cave.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {21733}, pmid = {33303927}, issn = {2045-2322}, mesh = {Bacteria/*genetics ; *Bacterial Physiological Phenomena ; Base Sequence ; Biofilms/*growth & development ; Hot Springs/*microbiology ; Hungary ; Microbiota ; Sequence Analysis, DNA ; Time Factors ; *Water Microbiology ; }, abstract = {Attachment of microorganisms to natural or artificial surfaces and the development of biofilms are complex processes which can be influenced by several factors. Nevertheless, our knowledge on biofilm formation in karstic environment is quite incomplete. The present study aimed to examine biofilm development for a year under controlled conditions in quasi-stagnant water of a hydrothermal spring cave located in the Buda Thermal Karst System (Hungary). Using a model system, we investigated how the structure of the biofilm is formed from the water and also how the growth rate of biofilm development takes place in this environment. Besides scanning electron microscopy, next-generation DNA sequencing was used to reveal the characteristic taxa and major shifts in the composition of the bacterial communities. Dynamic temporal changes were observed in the structure of bacterial communities. Bacterial richness and diversity increased during the biofilm formation, and 9-12 weeks were needed for the maturation. Increasing EPS production was also observed from the 9-12 weeks. The biofilm was different from the water that filled the cave pool, in terms of the taxonomic composition and metabolic potential of microorganisms. In these karstic environments, the formation of mature biofilm appears to take place relatively quickly, in a few months.}, } @article {pmid33303270, year = {2021}, author = {Kollakalnaduvil Raghavan, RM and Ali Pannippara, M and Kesav, S and Mathew, A and G Bhat, S and Hatha Aa, M and Kk, E}, title = {MFAP9: Characterization of an extracellular thermostable antibacterial peptide from marine fungus with biofilm eradication potential.}, journal = {Journal of pharmaceutical and biomedical analysis}, volume = {194}, number = {}, pages = {113808}, doi = {10.1016/j.jpba.2020.113808}, pmid = {33303270}, issn = {1873-264X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Bacillus ; *Biofilms ; Electrophoresis, Polyacrylamide Gel ; Fungi ; Humans ; Hydrogen-Ion Concentration ; Molecular Weight ; Peptides/pharmacology ; }, abstract = {An extracellular thermostable antibacterial peptide designated as MFAP9 was purified from marine Aspergillus fumigatus BTMF9 by ammonium sulfate precipitation followed by ion exchange chromatography on a DEAE-sepharose column. The molecular weight of MFAP9 was found to be∼3 kDa in SDS-PAGE gel corresponding a single intensity peak in MALDI-TOF. The distinct peak with a retention time of 32.5 min appeared in high performance liquid chromatography (HPLC), further confirming the purity. Isoelectric focusing, two-dimensional gel electrophoresis and peptide mass fingerprinting were performed for the characterization of MFAP9. Functional analysis of purified MFAP9 exhibited strong antibacterial activity against Bacillus circulans (NCIM 2107) with MIC and MBC values of 0.525 μg/mL and 4.2 μg/mL, respectively. The in vitro antibiofilm effect of MFAP9 was analyzed against bacteria which have strong biofilm forming potential. The antibiofilm effect of MFAP9 treatment on Bacillus pumilus was examined using scanning electron microscopy. MFAP9 was found to be active at high temperatures and a wide range of pH (28). In addition, it showed varied sensitivity towards proteolytic enzymes. The peptide was nontoxic to human RBCs at higher concentrations. These results indicate that MFAP9 is an antibacterial peptide, suitable for the development of novel anti-infective agent with strong antibiofilm potential.}, } @article {pmid33302332, year = {2020}, author = {Rochetti, VP and Rollin-Pinheiro, R and de Oliveira, EB and Xisto, MIDDS and Barreto-Bergter, E}, title = {Glucosylceramide Plays a Role in Fungal Germination, Lipid Raft Organization and Biofilm Adhesion of the Pathogenic Fungus Scedosporium aurantiacum.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {33302332}, issn = {2309-608X}, abstract = {Infections caused by Scedosporium species present a wide range of clinical manifestations, from superficial to disseminated, especially in immunocompromised patients. Glucosylceramides (GlcCer) are glycosphingolipids found on the fungal cell surface and play an important role in growth and pathogenicity processes in different fungi. The present study aimed to evaluate the structure of GlcCer and its role during growth in two S. aurantiacum isolates. Purified GlcCer from both isolates were obtained and its chemical structure identified by mass spectrometry. Using ELISA and immunofluorescence techniques it was observed that germination and NaOH-treatment of conidia favor GlcCer exposure. Monoclonal anti-GlcCer antibody reduced germination when cultivated with the inhibitor of melanin synthesis tricyclazole and also reduced germ tube length of conidia, both cultivated or not with tricyclazole. It was also demonstrated that anti-GlcCer altered lipid rafts organization, as shown by using the fluorescent stain filipin, but did not affect the susceptibility of the cell surface to damaging agents. Anti-GlcCer reduced total biomass and viability in biofilms formed on polystyrene plates. In the presence of anti-GlcCer, germinated S. aurantiacum conidia and biofilms could not adhere to polystyrene with the same efficacy as control cells. These results highlight the relevance of GlcCer in growth processes of S. aurantiacum.}, } @article {pmid33302174, year = {2021}, author = {Vendrell-Puigmitja, L and Llenas, L and Proia, L and Ponsa, S and Espinosa, C and Morin, S and Abril, M}, title = {Effects of an hypersaline effluent from an abandoned potash mine on freshwater biofilm and diatom communities.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {230}, number = {}, pages = {105707}, doi = {10.1016/j.aquatox.2020.105707}, pmid = {33302174}, issn = {1879-1514}, mesh = {Biofilms/*drug effects/growth & development ; Biomass ; *Complex Mixtures ; Diatoms/*drug effects/growth & development ; Ecosystem ; Fresh Water/*chemistry/microbiology ; Germany ; Microbiota/drug effects ; *Mining ; Salinity ; Water Pollutants, Chemical/analysis/*toxicity ; }, abstract = {Potash abandoned mines cause severe environmental damage to their bordering environment, with significant impacts on freshwater ecosystems mostly through uncontrolled discharge of hypersaline effluents. This study aimed to evaluate the ecological impact caused by a hypersaline effluent from an abandoned potash mine (Menteroda, Germany) on freshwater biofilms and, specifically, on diatom communities. Biofilm from a pristine stream was exposed under controlled conditions in microcosms to a mining effluent (ME), and its structural (algal biomass, community composition, diatom metrics) and functional (photosynthetic activity, nutrient uptake) responses were evaluated over time and compared with unexposed biofilms used as control. Biofilm exposed to ME showed drastic functional responses after one day of exposure, with a significant decrease in photosynthetic efficiency and nutrient uptake, that were recovered over time. Biofilm exposed to ME showed a progressive increase in diatom metrics (abundance, density and growth rate) over time, compared to the control. However, a significant decrease in diatom species diversity, richness and cell size was also observed in biofilm exposed to ME. This study revealed that the ME affected the biofilm causing short-term functional responses, which were recovered simultaneously with a drastic diatom community structure shift.}, } @article {pmid33302119, year = {2021}, author = {Huang, Y and Liu, Y and Shah, S and Kim, D and Simon-Soro, A and Ito, T and Hajfathalian, M and Li, Y and Hsu, JC and Nieves, LM and Alawi, F and Naha, PC and Cormode, DP and Koo, H}, title = {Precision targeting of bacterial pathogen via bi-functional nanozyme activated by biofilm microenvironment.}, journal = {Biomaterials}, volume = {268}, number = {}, pages = {120581}, pmid = {33302119}, issn = {1878-5905}, support = {R01 DE025848/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; *Dental Caries/drug therapy ; Humans ; *Hydrogen Peroxide ; Microbial Interactions ; Streptococcus mutans ; }, abstract = {Human dental caries is an intractable biofilm-associated disease caused by microbial interactions and dietary sugars on the host's teeth. Commensal bacteria help control opportunistic pathogens via bioactive products such as hydrogen peroxide (H2O2). However, high-sugar consumption disrupts homeostasis and promotes pathogen accumulation in acidic biofilms that cause tooth-decay. Here, we exploit the pathological (sugar-rich/acidic) conditions using a nanohybrid system to increase intrinsic H2O2 production and trigger pH-dependent reactive oxygen species (ROS) generation for efficient biofilm virulence targeting. The nanohybrid contains glucose-oxidase that catalyzes glucose present in biofilms to increase intrinsic H2O2, which is converted by iron oxide nanoparticles with peroxidase-like activity into ROS in acidic pH. Notably, it selectively kills Streptococcus mutans (pathogen) without affecting Streptococcus oralis (commensal) via preferential pathogen-binding and in situ ROS generation. Furthermore, nanohybrid treatments potently reduced dental caries in a rodent model. Compared to chlorhexidine (positive-control), which disrupted oral microbiota diversity, the nanohybrid had significant higher efficacy without affecting soft-tissues and the oral-gastrointestinal microbiomes, while modulating dental health-associated microbial activity in vivo. The data reveal therapeutic precision of a bi-functional hybrid nanozyme against a biofilm-related disease in a controlled-manner activated by pathological conditions.}, } @article {pmid33300966, year = {2020}, author = {Grobas, I and Bazzoli, DG and Asally, M}, title = {Biofilm and swarming emergent behaviours controlled through the aid of biophysical understanding and tools.}, journal = {Biochemical Society transactions}, volume = {48}, number = {6}, pages = {2903-2913}, pmid = {33300966}, issn = {1470-8752}, support = {MR/N014294/1/MRC_/Medical Research Council/United Kingdom ; BB/M017982/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M01116X/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacteria/growth & development ; Bioengineering ; *Biofilms ; Biophysics/*methods ; Biotechnology/*methods ; Cell Shape ; Computer Simulation ; Microbiota ; Motion ; Synthetic Biology ; }, abstract = {Bacteria can organise themselves into communities in the forms of biofilms and swarms. Through chemical and physical interactions between cells, these communities exhibit emergent properties that individual cells alone do not have. While bacterial communities have been mainly studied in the context of biochemistry and molecular biology, recent years have seen rapid advancements in the biophysical understanding of emergent phenomena through physical interactions in biofilms and swarms. Moreover, new technologies to control bacterial emergent behaviours by physical means are emerging in synthetic biology. Such technologies are particularly promising for developing engineered living materials (ELM) and devices and controlling contamination and biofouling. In this minireview, we overview recent studies unveiling physical and mechanical cues that trigger and affect swarming and biofilm development. In particular, we focus on cell shape, motion and density as the key parameters for mechanical cell-cell interactions within a community. We then showcase recent studies that use physical stimuli for patterning bacterial communities, altering collective behaviours and preventing biofilm formation. Finally, we discuss the future potential extension of biophysical and bioengineering research on microbial communities through computational modelling and deeper investigation of mechano-electrophysiological coupling.}, } @article {pmid33300127, year = {2021}, author = {Boudarel, H and Mathias, JD and Blaysat, B and Grédiac, M}, title = {In situ tracking of microbeads for the detection of biofilm formation.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {3}, pages = {1244-1261}, doi = {10.1002/bit.27648}, pmid = {33300127}, issn = {1097-0290}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; *Microspheres ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; }, abstract = {In this study, we utilize the free motion of beads incorporated in bacterial suspension to investigate the behavior of the medium surrounding the beads during biofilm formation. The use of imaging techniques such as digital image correlation enables tracking of the movement of beads, which serve as markers in the processed images. This method is applied to detect and characterize biofilm formation. The main originality of this study lies in characterizing the evolution of the typology of bead movements during biofilm formation. The aim is to identify bead behaviors that represent the start of biofilm formation. By observing inert bead movements introduced into the bacterial environment, changes in trajectory typologies are detected and appear to be related to sessile bacterial activity, bacterial hindrance, and adhesion or formation of extracellular material. We use our approach to discriminate between the presence or absence of antibiotics mixed with bacteria and to assess their effectiveness. The results highlight the potential of our approach as nondestructive tracking of biofilm dynamics over time based on optical microscope images.}, } @article {pmid33297180, year = {2021}, author = {Wang, B and Li, H and Liu, T and Guo, J}, title = {Enhanced removal of cephalexin and sulfadiazine in nitrifying membrane-aerated biofilm reactors.}, journal = {Chemosphere}, volume = {263}, number = {}, pages = {128224}, doi = {10.1016/j.chemosphere.2020.128224}, pmid = {33297180}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; *Cephalexin ; Nitrification ; *Sulfadiazine ; }, abstract = {Nitrification process has been reported to be capable of degrading various pharmaceuticals due to the cometabolism of ammonia-oxidizing bacteria (AOB). The membrane aerated biofilm reactor (MABR) is an emerging configuration in wastewater treatment with advantages of high nitrification rate and low energy consumption. However, there are very few studies investigating the degradation of antibiotics at environmentally relevant levels in nitrifying MABR systems. In this study, the removal of two widely used antibiotics, cephalexin (CFX) and sulfadiazine (SDZ), was evaluated in two independent MABRs with nitrifying biofilms. The impacts of CFX and SDZ exposure on the nitrification performance and microbial community structure within biofilms were also investigated. The results showed that nitrifying biofilms were very efficient in removing CFX (94.6%) and SDZ (75.4%) with an initial concentration of 100 μg/L when hydraulic retention time (HRT) was 4 h in the reactors. When HRT decreased from 4 h to 3 h, the removal rates of CFX and SDZ increased significantly from 23.4 ± 1.0 μg/(L·h) and 18.7 ± 1.1 μg/(L·h), respectively, to 27.7 ± 1.3 μg/(L·h) (p＜0.01) and 20.8 ± 2.4 μg/(L·h) (p＜0.05), while the removal efficiencies decreased to 86.0% and 61.5%, respectively. Despite the exposure to CFX and SDZ, the nitrification performance was not affected, and microbial community structure within biofilms also remained relatively stable. This study shows that nitrifying MABR process is a promising option for the efficient removal of antibiotics from domestic wastewater.}, } @article {pmid33295079, year = {2021}, author = {Delgado Vela, J and Bristow, LA and Marchant, HK and Love, NG and Dick, GJ}, title = {Sulfide alters microbial functional potential in a methane and nitrogen cycling biofilm reactor.}, journal = {Environmental microbiology}, volume = {23}, number = {3}, pages = {1481-1495}, doi = {10.1111/1462-2920.15352}, pmid = {33295079}, issn = {1462-2920}, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Methane ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Sulfides ; }, abstract = {Cross-feeding of metabolites between coexisting cells leads to complex and interconnected elemental cycling and microbial interactions. These relationships influence overall community function and can be altered by changes in substrate availability. Here, we used isotopic rate measurements and metagenomic sequencing to study how cross-feeding relationships changed in response to stepwise increases of sulfide concentrations in a membrane-aerated biofilm reactor that was fed with methane and ammonium. Results showed that sulfide: (i) decreased nitrite oxidation rates but increased ammonia oxidation rates; (ii) changed the denitrifying community and increased nitrous oxide production; and (iii) induced dissimilatory nitrite reduction to ammonium (DNRA). We infer that inhibition of nitrite oxidation resulted in higher nitrite availability for DNRA, anammox, and nitrite-dependent anaerobic methane oxidation. In other words, sulfide likely disrupted microbial cross-feeding between AOB and NOB and induced cross-feeding between AOB and nitrite reducing organisms. Furthermore, these cross-feeding relationships were spatially distributed between biofilm and planktonic phases of the reactor. These results indicate that using sulfide as an electron donor will promote N2 O and ammonium production, which is generally not desirable in engineered systems.}, } @article {pmid33291608, year = {2020}, author = {Papa, R and Garzoli, S and Vrenna, G and Sabatino, M and Sapienza, F and Relucenti, M and Donfrancesco, O and Fiscarelli, EV and Artini, M and Selan, L and Ragno, R}, title = {Essential Oils Biofilm Modulation Activity, Chemical and Machine Learning Analysis. Application on Staphylococcus aureus Isolates from Cystic Fibrosis Patients.}, journal = {International journal of molecular sciences}, volume = {21}, number = {23}, pages = {}, pmid = {33291608}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Chemical Phenomena ; Cystic Fibrosis/*complications ; Gas Chromatography-Mass Spectrometry ; Machine Learning ; Microbial Sensitivity Tests ; Oils, Volatile/*chemistry/*pharmacology ; Staphylococcal Infections/*etiology ; Staphylococcus aureus/*drug effects/isolation & purification ; }, abstract = {Bacterial biofilm plays a pivotal role in chronic Staphylococcus aureus (S. aureus) infection and its inhibition may represent an important strategy to develop novel therapeutic agents. The scientific community is continuously searching for natural and "green alternatives" to chemotherapeutic drugs, including essential oils (EOs), assuming the latter not able to select resistant strains, likely due to their multicomponent nature and, hence, multitarget action. Here it is reported the biofilm production modulation exerted by 61 EOs, also investigated for their antibacterial activity on S. aureus strains, including reference and cystic fibrosis patients' isolated strains. The EOs biofilm modulation was assessed by Christensen method on five S. aureus strains. Chemical composition, investigated by GC/MS analysis, of the tested EOs allowed a correlation between biofilm modulation potency and putative active components by means of machine learning algorithms application. Some EOs inhibited biofilm growth at 1.00% concentration, although lower concentrations revealed different biological profile. Experimental data led to select antibiofilm EOs based on their ability to inhibit S. aureus biofilm growth, which were characterized for their ability to alter the biofilm organization by means of SEM studies.}, } @article {pmid33291554, year = {2020}, author = {Pleeging, CCF and Coenye, T and Mossialos, D and de Rooster, H and Chrysostomou, D and Wagener, FADTG and Cremers, NAJ}, title = {Synergistic Antimicrobial Activity of Supplemented Medical-Grade Honey against Pseudomonas aeruginosa Biofilm Formation and Eradication.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33291554}, issn = {2079-6382}, abstract = {Biofilms hinder wound healing. Medical-grade honey (MGH) is a promising therapy because of its broad-spectrum antimicrobial activity and the lack of risk for resistance. This study investigated the inhibitory and eradicative activity against multidrug-resistant Pseudomonas aeruginosa biofilms by different established MGH-based wound care formulations. Six different natural wound care products (Medihoney, Revamil, Mebo, Melladerm, L-Mesitran Ointment, and L-Mesitran Soft) were tested in vitro. Most of them contain MGH only, whereas some were supplemented. L-Mesitran Soft demonstrated the most potent antimicrobial activity (6.08-log inhibition and 3.18-log eradication). Other formulations ranged between 0.89-log and 4.80-log inhibition and 0.65-log and 1.66-log eradication. Therefore, the contribution of different ingredients of L-Mesitran Soft was investigated in more detail. The activity of the same batch of raw MGH (1.38-log inhibition and 2.35-log eradication), vitamins C and E (0.95-log inhibition and 0.94-log eradication), and all ingredients except MGH (1.69-log inhibition and 0.75-log eradication) clearly support a synergistic activity of components within the L-Mesitran Soft formulation. Several presented clinical cases illustrate its clinical antimicrobial efficacy against Pseudomonas aeruginosa biofilms. In conclusion, MGH is a potent treatment for Pseudomonas biofilms. L-Mesitran Soft has the strongest antimicrobial activity, which is likely due to the synergistic activity mediated by its supplements.}, } @article {pmid33291521, year = {2020}, author = {Wei, H and Xie, Z and Tan, X and Guo, R and Song, Y and Xie, X and Wang, R and Li, L and Wang, M and Zhang, Y}, title = {Temporin-Like Peptides Show Antimicrobial and Anti-Biofilm Activities against Streptococcus mutans with Reduced Hemolysis.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {23}, pages = {}, pmid = {33291521}, issn = {1420-3049}, support = {31560593.//National Natural Science Foundation of China/ ; 2019RC026//High-level Talent Project of Hainan Basic and Applied Basic Research Program (natural science)/ ; }, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Cell Membrane/microbiology ; Dental Caries/microbiology ; Epithelial Cells/microbiology ; Erythrocytes/microbiology ; Hemolysis/*drug effects ; Humans ; Microbial Sensitivity Tests/methods ; Peptides/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {In our previous study, temporin-GHaR (GHaR) showed potent antimicrobial activity with strong hemolytic toxicity. To overcome its weakness, we designed GHaR6R, GHaR7R, GHaR8R, GHaR9R, and GHaR9W by changing the number of positive charges and the hydrophobic surface of GHaR. With the exception of GHaR7R, the hemolytic toxicity of the derived peptides had been reduced, and the antimicrobial activities remained close to the parent peptide (except for GHaR9R). GHaR6R, GHaR7R, GHaR8R, and GHaR9W exhibited a great bactericidal effect on Streptococcus mutans (S. mutans), which is one of the main pathogens causing dental caries. According to the membrane permeation and scanning electron microscope (SEM) analysis, these derived peptides targeted to the cell membranes of planktonic bacteria, contributing to the disruption of the membrane integrity and leakage of the intracellular contents. Moreover, they inhibited the formation of biofilms and eradicated the mature biofilms of S. mutans. Compared with GHaR7R, the derived peptides showed less cytotoxicity to human oral epithelial cells (HOECs). The derived peptides are expected to be the molecular templates for designing antibacterial agents to prevent dental caries.}, } @article {pmid33291344, year = {2020}, author = {Patel, N and Swavey, S and Robinson, J}, title = {A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33291344}, issn = {2079-6382}, abstract = {One of the greatest threats to human health is the rise in antibiotic-resistant bacterial infections. Pseudomonas aeruginosa (PsA) is an "opportunistic" pathogen known to cause life-threatening infections in immunocompromised individuals and is the most common pathogen in adults with cystic fibrosis (CF). We report here a cationic zinc (II) porphyrin, ZnPor, that effectively kills planktonic and biofilm-associated cells of PsA. In standard tests against 16-18 h-old biofilms, concentrations as low as 16 µg/mL resulted in the extensive disruption and detachment of the matrix. The pre-treatment of biofilms for 30 min with ZnPor at minimum inhibitory concentration (MIC) levels (4 µg/mL) substantially enhanced the ability of tobramycin (Tobra) to kill biofilm-associated cells. We demonstrate the rapid uptake and accumulation of ZnPor in planktonic cells even in dedicated heme-uptake system mutants (ΔPhu, ΔHas, and the double mutant). Furthermore, uptake was unaffected by the ionophore carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Cells pre-exposed to ZnPor took up the cell-impermeant dye SYTOX[TM] Green in a concentration-dependent manner. The accumulation of ZnPor did not result in cell lysis, nor did the cells develop resistance. Taken together, these properties make ZnPor a promising candidate for treating multi-drug-resistant infections, including persistent, antibiotic-resistant biofilms.}, } @article {pmid33291216, year = {2020}, author = {Pompa-Monroy, DA and Figueroa-Marchant, PG and Dastager, SG and Thorat, MN and Iglesias, AL and Miranda-Soto, V and Pérez-González, GL and Villarreal-Gómez, LJ}, title = {Bacterial Biofilm Formation Using PCL/Curcumin Electrospun Fibers and Its Potential Use for Biotechnological Applications.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {23}, pages = {}, pmid = {33291216}, issn = {1996-1944}, support = {INFR-2011-3-173395//Consejo Nacional de Ciencia y Tecnología (CONACYT)/ ; FONCICYT-266380//Consejo Nacional de Ciencia y Tecnología (CONACYT)/ ; }, abstract = {Electrospun nanofibers are used for many applications due to their large surface area, mechanical properties, and bioactivity. Bacterial biofilms are the cause of numerous problems in biomedical devices and in the food industry. On the other hand, these bacterial biofilms can produce interesting metabolites. Hence, the objective of this study is to evaluate the efficiency of poly (Ɛ- caprolactone)/Curcumin (PCL/CUR) nanofibers to promote bacterial biofilm formation. These scaffolds were characterized by scanning electron microscopy (SEM), which showed homogeneous fibers with diameters between 441-557 nm; thermogravimetric analysis and differential scanning calorimetry (TGA and DSC) demonstrated high temperature resilience with degradation temperatures over >350 °C; FTIR and [1]H-NMR serve as evidence of CUR incorporation in the PCL fibers. PCL/CUR scaffolds successfully promoted the formation of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa biofilms. These results will be valuable in the study of controlled harvesting of pathogenic biofilms as well as in metabolites production for biotechnological purposes.}, } @article {pmid33290953, year = {2021}, author = {Song, T and Li, S and Yin, Z and Bao, M and Lu, J and Li, Y}, title = {Hydrolyzed polyacrylamide-containing wastewater treatment using ozone reactor-upflow anaerobic sludge blanket reactor-aerobic biofilm reactor multistage treatment system.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {269}, number = {}, pages = {116111}, doi = {10.1016/j.envpol.2020.116111}, pmid = {33290953}, issn = {1873-6424}, mesh = {Acrylic Resins ; Anaerobiosis ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; *Ozone ; Sewage ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {Polymer flooding is one of the most important enhanced oil recovery techniques. However, a large amount of hydrolyzed polyacrylamide (HPAM)-containing wastewater is produced in the process of polymer flooding, and this poses a potential threat to the environment. In this study, the treatment of HPAM-containing wastewater was analyzed in an ozonic-anaerobic-aerobic multistage treatment process involving an ozone reactor (OR), an upflow anaerobic sludge blanket reactor (UASBR), and an aerobic biofilm reactor (ABR). At an HPAM concentration of 500 mg L[-1] and an ozone dose of 25 g O3/g TOC, the HPAM removal rate reached 85.06%. With fracturing of the carbon chain, high-molecular-weight HPAM was degraded into low-molecular-weight compounds. Microbial communities in bioreactors were investigated via high-throughput sequencing, which revealed that norank_c_Bacteroidetes_vadinHA17, norank_f_Cytophagaceae, and Meiothermus were the dominant bacterial groups, and that Methanobacterium, norank_c_WCHA1-57, and Methanosaeta were the key archaeal genera. To the best of our knowledge, this is the first study in which HPAM-containing wastewater is treated using an ozonic-anaerobic-aerobic multistage treatment system. The ideal degradation performance and the presence of keystone microorganisms confirmed that the multistage treatment process is feasible for treatment of HPAM-containing wastewater.}, } @article {pmid33288715, year = {2020}, author = {Bridges, AA and Fei, C and Bassler, BL}, title = {Identification of signaling pathways, matrix-digestion enzymes, and motility components controlling Vibrio cholerae biofilm dispersal.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {51}, pages = {32639-32647}, pmid = {33288715}, issn = {1091-6490}, support = {R37 GM065859/GM/NIGMS NIH HHS/United States ; DRG-2302-17/HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Adhesins, Bacterial/genetics/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism ; Biofilms/drug effects/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Enzymes/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Mutation ; Operon ; Signal Transduction ; Time-Lapse Imaging ; Vibrio cholerae/drug effects/genetics/pathogenicity/*physiology ; }, abstract = {Bacteria alternate between being free-swimming and existing as members of sessile multicellular communities called biofilms. The biofilm lifecycle occurs in three stages: cell attachment, biofilm maturation, and biofilm dispersal. Vibrio cholerae biofilms are hyperinfectious, and biofilm formation and dispersal are considered central to disease transmission. While biofilm formation is well studied, almost nothing is known about biofilm dispersal. Here, we conducted an imaging screen for V. cholerae mutants that fail to disperse, revealing three classes of dispersal components: signal transduction proteins, matrix-degradation enzymes, and motility factors. Signaling proteins dominated the screen and among them, we focused on an uncharacterized two-component sensory system that we term DbfS/DbfR for dispersal of biofilm sensor/regulator. Phospho-DbfR represses biofilm dispersal. DbfS dephosphorylates and thereby inactivates DbfR, which permits dispersal. Matrix degradation requires two enzymes: LapG, which cleaves adhesins, and RbmB, which digests matrix polysaccharides. Reorientation in swimming direction, mediated by CheY3, is necessary for cells to escape from the porous biofilm matrix. We suggest that these components act sequentially: signaling launches dispersal by terminating matrix production and triggering matrix digestion, and subsequent cell motility permits escape from biofilms. This study lays the groundwork for interventions aimed at modulating V. cholerae biofilm dispersal to ameliorate disease.}, } @article {pmid33288255, year = {2021}, author = {Yu, J and Widyaningsih, E and Park, Y and Lee, T}, title = {Nitrogen removal and microbial community diversity in single-chamber electroactive biofilm reactors with different ratios of the cathode surface area to reactor volume.}, journal = {The Science of the total environment}, volume = {758}, number = {}, pages = {143677}, doi = {10.1016/j.scitotenv.2020.143677}, pmid = {33288255}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Electrodes ; *Microbiota ; Nitrification ; *Nitrogen ; Wastewater ; }, abstract = {Removal of nitrogen compounds is particularly important domestic wastewater treatment. Our recent study reported the successful removal of nitrogen in single-chamber electroactive biofilm reactors (EBRs) under aeration-free conditions. We hypothesized that the oxygen diffused from the air-cathode is a key factor in the removal of nitrogen in the EBR. If so, the effect of the penetrated oxygen would vary according to the ratio of the air-cathode surface area to the reactor volume (AV ratio) and the hydraulic retention time (HRT). In this study, single-chamber EBRs with three different AV ratios: 125 m[2]/m[3] (EBR-125), 250 m[2]/m[3] (EBR-250), and 500 m[2]/m[3] (EBR-500) were evaluated for the removal of nitrogen under different HRTs of 0.5-6 h. The higher the AV ratio, the greater the increase in nitrification. The total nitrogen (TN) removal efficiency of EBR-125 and EBR-250 decreased as the HRT decreased, while that of EBR-500 increased. EBR-250 showed the highest TN removal (62.0%) with well-balanced nitrification (83.9%) and denitrification (75.1%) at an HRT of 6 h. However, EBR-500 appeared to be superior for practical application because it showed a comparable TN removal (59%) at a substantially short HRT of 1 h. The microbial communities that were involved in the nitrogen cycle varied according to whether the biofilms were located on the anodes, separators, and cathodes but were similar among EBRs with different AV ratios. Nitrifying bacteria were detected in the biofilms that were presented on the cathodes (approximately 7.8% of the total phylotypes), while denitrifying bacteria were mainly found in biofilm that were located on the anodes (approximately 23.3%). Anammox bacteria were also detected on the anode (approximately 3.7%) and in the separator biofilms (approximately 1.9%) of all the EBRs. These results suggest that both the A/V ratio and the HRT could affect the counter diffusion of substrates (NH4[+] and organic compounds) and oxygen in the biofilms and allow interactions between a diversity of microorganisms for the successful removal of nitrogen in EBRs. These findings are expected to aid in the development of new applications using EBR for energy-saving wastewater treatment.}, } @article {pmid33287445, year = {2020}, author = {Castaño-Arriba, A and González-Machado, C and Igrejas, G and Poeta, P and Alonso-Calleja, C and Capita, R}, title = {Antibiotic Resistance and Biofilm-Forming Ability in Enterococcal Isolates from Red Meat and Poultry Preparations.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {12}, pages = {}, pmid = {33287445}, issn = {2076-0817}, support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; }, abstract = {This study investigated the resistance to antibiotics and the capacity to form a biofilm of 200 isolates of enterococci isolated from raw preparations of beef (51 strains), pork (47), chicken (50), and turkey (52) acquired in north-western Spain. Fifteen antimicrobials of clinical importance were tested by the disc diffusion method. The average number of resistances per strain was 4.48 ± 1.59. If resistant strains were taken together with those showing reduced susceptibility, the total number of resistances per strain was 6.97 ± 2.02. Two isolates (1.0% of strains) were resistant to a single antibiotic, twenty-two isolates (11.0%) presented resistance to two, one strain (0.5%) was resistant to three, and 175 isolates (87.5%) showed a multiple drug-resistant phenotype (MDR; defined as no susceptibility to at least one agent from each of three or more antimicrobial categories). The prevalence of resistance varied between 0.5% (gentamicin) and 100% (kanamycin). All strains produced biofilm on polystyrene microwell plates, determined using crystal violet assay. Isolates were classified as having a weak (51 strains; average optical density at 580 nanometers -OD580- = 0.206 ± 0.033), moderate (78 strains; average OD580 = 0.374 ± 0.068), or strong (71 strains; average OD580 = 1.167 ± 0.621) ability to produce biofilm (p < 0.05). Isolates from beef preparations produced the most substantial (p < 0.05) biofilms. The results of this study indicate that meat and poultry preparations are major reservoirs of antibiotic-resistant enterococcal strains capable of forming a biofilm. In order for food-borne infections to be prevented, the importance of careful handling of these foodstuffs during preparation, avoiding cross-contamination, and ensuring thorough cooking, is stressed.}, } @article {pmid33287389, year = {2020}, author = {Cataneli Pereira, V and Pinheiro-Hubinger, L and de Oliveira, A and Moraes Riboli, DF and Benini Martins, K and Calixto Romero, L and Ribeiro de Souza da Cunha, ML}, title = {Detection of the agr System and Resistance to Antimicrobials in Biofilm-Producing S. epidermidis.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {23}, pages = {}, pmid = {33287389}, issn = {1420-3049}, support = {2011/23742-2//State funding agency São Paulo Research Foundation (FAPESP)/ ; 304051/2017-9//National Council for Scientific and Technological Development (CNPq)/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects ; Brazil ; Drug Resistance, Bacterial/*drug effects ; Electrophoresis, Gel, Pulsed-Field/methods ; Humans ; Microbial Sensitivity Tests/methods ; Multilocus Sequence Typing/methods ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus epidermidis/*drug effects/*metabolism ; Virginiamycin/pharmacology ; }, abstract = {The ability of Staphylococcus epidermidis to produce virulence factors, such as biofilm, added to its increased resistance to antimicrobials can cause infections that are difficult to treat. Many staphylococcal virulence factors are under the control of the accessory gene regulator (agr). The objective of this study was to establish the agr locus and susceptibility of biofilm-producing S. epidermidis specimens to antimicrobial agents, through PCR reactions, reverse transcription polymerase chain reaction (RT-PCR), and the determination of minimum inhibitory concentration (MIC), and to analyze the clonal profile of 300 strains isolated from blood culture specimens from inpatients at a University Hospital in Brazil, over a 20-year period by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) techniques. The ica operon expression was shown in 83.6% strains, bhp gene in 11.5%, and aap gene in 32.8%. Oxacillin resistance was detected in 90.1%, while 4.9% showed tigecycline resistance, and intermediate resistance to quinupristin/dalfopristin was identified in 0.4%. Clonal profile determination showed 11 clusters, with the ST2 type determined as the major cluster. The S. epidermidis biofilm producer demonstrated a predominance of agr I locus, oxacillin resistance, and SCCmec III as well as the potential dissemination of pathogenic clones in hospital settings over long periods.}, } @article {pmid33285963, year = {2020}, author = {Carpio, A and Cebrián, E}, title = {Incorporating Cellular Stochasticity in Solid-Fluid Mixture Biofilm Models.}, journal = {Entropy (Basel, Switzerland)}, volume = {22}, number = {2}, pages = {}, pmid = {33285963}, issn = {1099-4300}, support = {MTM2017-84446-C2-1-R//Ministerio de Ciencia, Innovación y Universidades/ ; PRX18/00112//Ministerio de Ciencia, Innovación y Universidades/ ; }, abstract = {The dynamics of cellular aggregates is driven by the interplay of mechanochemical processes and cellular activity. Although deterministic models may capture mechanical features, local chemical fluctuations trigger random cell responses, which determine the overall evolution. Incorporating stochastic cellular behavior in macroscopic models of biological media is a challenging task. Herein, we propose hybrid models for bacterial biofilm growth, which couple a two phase solid/fluid mixture description of mechanical and chemical fields with a dynamic energy budget-based cellular automata treatment of bacterial activity. Thin film and plate approximations for the relevant interfaces allow us to obtain numerical solutions exhibiting behaviors observed in experiments, such as accelerated spread due to water intake from the environment, wrinkle formation, undulated contour development, and the appearance of inhomogeneous distributions of differentiated bacteria performing varied tasks.}, } @article {pmid33285505, year = {2021}, author = {Pratofiorito, G and Hackbarth, M and Mandel, C and Madlanga, S and West, S and Horn, H and Hille-Reichel, A}, title = {A membrane biofilm reactor for hydrogenotrophic methanation.}, journal = {Bioresource technology}, volume = {321}, number = {}, pages = {124444}, doi = {10.1016/j.biortech.2020.124444}, pmid = {33285505}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Hydrogen ; *Methane ; }, abstract = {Biomethanation of CO2 has been proven to be a feasible way to produce methane with the employment of H2 as electron source. Subject of the present study is a custom-made membrane biofilm reactor for hydrogenotrophic methanation by archaeal biofilms cultivated on membrane surfaces. Reactor layout was adapted to allow for in situ biofilm analysis via optical coherence tomography. At a feeding ratio of H2/CO2 of 3.6, and despite the low membrane surface to reactor volume ratio of 57.9 m[2] m[-3], the maximum methane production per reactor volume reached up to 1.17 Nm[3] m[-3] d[-1] at a methane content of the produced gas above 97% (v/v). These results demonstrate that the concept of membrane bound biofilms enables improved mass transfer by delivering substrate gases directly to the biofilm, thus, rendering the bottleneck of low solubility of hydrogen in water less drastic.}, } @article {pmid33285221, year = {2021}, author = {Brilhante, RSN and Fernandes, MR and Pereira, VS and Costa, ADC and Oliveira, JS and de Aguiar, L and Rodrigues, AM and de Camargo, ZP and Pereira-Neto, WA and Sidrim, JJC and Rocha, MFG}, title = {Biofilm formation on cat claws by Sporothrix species: An ex vivo model.}, journal = {Microbial pathogenesis}, volume = {150}, number = {}, pages = {104670}, doi = {10.1016/j.micpath.2020.104670}, pmid = {33285221}, issn = {1096-1208}, mesh = {Animals ; Biofilms ; *Cat's Claw ; *Sporothrix ; *Sporotrichosis/veterinary ; }, abstract = {This work aimed to evaluate the ability of Sporothrix species to attach and form biofilm on the surface of cat claws as an ex vivo model. A total of 14 strains (5 Sporothrix brasiliensis, 3 Sporothrix schenckii s. str., 3 Sporothrix globosa and 3 Sporothrix mexicana) were used. The biofilms were incubated for periods of 01, 03, 07, 10 and fifteenth 15 days. Their metabolic activities were evaluated by the XTT reduction assay and the morphology and structure were investigated by scanning electron microscopy (SEM). The analysis of the SEM images revealed that all the species can form biofilms on cat claws. The metabolic activity in the ex vivo biofilms was similar to that found in in vitro biofilms when incubated for the same period. This is the first report of an ex vivo biofilm model involving cat claws. The ability to form biofilms on cat claws can increase the viable period of the fungus and consequently the number of possibly infected animals and people.}, } @article {pmid33284019, year = {2021}, author = {Lencova, S and Svarcova, V and Stiborova, H and Demnerova, K and Jencova, V and Hozdova, K and Zdenkova, K}, title = {Bacterial Biofilms on Polyamide Nanofibers: Factors Influencing Biofilm Formation and Evaluation.}, journal = {ACS applied materials & interfaces}, volume = {13}, number = {2}, pages = {2277-2288}, doi = {10.1021/acsami.0c19016}, pmid = {33284019}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Anti-Infective Agents, Local/chemistry/pharmacology ; Bacteria/*drug effects ; Bacterial Adhesion/drug effects ; Bacterial Infections/microbiology/prevention & control ; Biofilms/*drug effects ; Escherichia coli/drug effects/physiology ; Humans ; Nanofibers/chemistry/*microbiology/ultrastructure ; Nylons/chemistry/*pharmacology ; Silver Nitrate/chemistry/pharmacology ; Staphylococcus aureus/drug effects/physiology ; Staphylococcus epidermidis/drug effects/physiology ; }, abstract = {Electrospun polyamide (PA) nanofibers have great potential for medical applications (in dermatology as antimicrobial compound carriers or surgical sutures). However, little is known about microbial colonization on these materials. Suitable methods need to be chosen and optimized for the analysis of biofilms formed on nanofibers and the influence of their morphology on biofilm formation. We analyzed 11 PA nanomaterials, both nonfunctionalized and functionalized with AgNO3, and tested the formation of a biofilm by clinically relevant bacteria (Escherichia coli CCM 4517, Staphylococcus aureus CCM 3953, and Staphylococcus epidermidis CCM 4418). By four different methods, it was confirmed that all of these bacteria attached to the PAs and formed biofilms; however, it was found that the selected method can influence the outcomes. For studying biofilms formed by the selected bacteria, scanning electron microscopy, resazurin staining, and colony-forming unit enumeration provided appropriate and comparable results. The values obtained by crystal violet (CV) staining were misleading due to the binding of the CV dye to the PA structure. In addition, the effect of nanofiber morphology parameters (fiber diameter and air permeability) and AgNO3 functionalization significantly influenced biofilm maturation. Furthermore, the correlations between air permeability and surface density and fiber diameter were revealed. Based on the statistical analysis, fiber diameter was confirmed as a crucial factor influencing biofilm formation (p ≤ 0.01). The functionalization of PAs with AgNO3 (from 0.1 wt %) effectively suppressed biofilm formation. The PA functionalized with a concentration of 0.1 wt % AgNO3 influenced the biofilm equally as nonfunctionalized PA 8% 2 g/m[2]. Therefore, biofilm formation could be affected by the above-mentioned morphology parameters, and ultimately, the risk of infections from contaminated medical devices could be reduced.}, } @article {pmid33282773, year = {2020}, author = {Leoney, A and Karthigeyan, S and Asharaf, AS and Felix, AJW}, title = {Detection and Categorization of Biofilm-forming Staphylococcus aureus, Viridans streptococcus, Klebsiella pneumoniae, and Escherichia coli Isolated from Complete Denture Patients and Visualization Using Scanning Electron Microscopy.}, journal = {Journal of International Society of Preventive & Community Dentistry}, volume = {10}, number = {5}, pages = {627-633}, pmid = {33282773}, issn = {2231-0762}, abstract = {AIMS: Complete denture patients have a plethora of microorganisms inhabiting their complete dentures. Some bacteria are capable of causing systemic illness such as aspiration pneumonia and infective endocarditis. Hence, detection as well as the categorization of biofilms, which form on the denture surface is vital in the study of denture biofilm-associated local and systemic diseases. This study aimed at the detection and categorization of biofilm-forming Staphylococcus aureus, Viridans streptococcus, Klebsiella pneumoniae, and Escherichia coli isolated from complete dentures and visualization of biofilms using scanning electron microscopy (SEM).

MATERIALS AND METHODS: Thirty complete denture patients were selected for the study and swabs were collected from their complete denture surfaces. Isolation of the bacteria was done using selective media and confirmed using biochemical tests and 16SrRNA sequencing. The bacteria were subjected to biofilm assays via Microtiter plate assay. The biofilm-forming bacteria were categorized as weak, moderate, and strong biofilm formers based on optical density (OD) values. As a visual confirmation of the biofilms, scanning electron microscopic (SEM) images were taken for each of the strong biofilm-forming bacteria. Descriptive statistical analysis was carried out with the help of Statistical Package for the Social Sciences (SPSS) statistical package version 20.0.

RESULTS: The average OD of S. aureus was 1. 333±0. 015 and the average OD of V. streptococcus species was 1. 304 ± 0.023. The average OD value of K. pneumoniae was 0.8 ± 0.012 and the average value of E. coli was 1.014 ± 0.01.

CONCLUSIONS: The study of biofilms especially the strongly biofilm formers is very useful to understand the potential pathogenic effect of biofilms. These biofilms cause the systemic spread of the planktonic bacteria which could lead to systemic diseases that are resistant to conventional treatment. This could be due to the inherent nature of the biofilm to offer drug resistance to existing antibacterial agents.}, } @article {pmid33282763, year = {2020}, author = {Jara, M and Salcedo-Moncada, D and Ayala, G and Watanabe, R and Alvítez-Temoche, D and Mayta-Tovalino, F}, title = {Antibacterial Efficacy of Calcium Hydroxide with Iodoform versus Calcium Hydroxide with Camphorated Paramonochlorophenol as Intrachannel Pastes on an Enterococcus faecalis Biofilm: A Comparative In Vitro Study.}, journal = {Journal of International Society of Preventive & Community Dentistry}, volume = {10}, number = {5}, pages = {555-560}, pmid = {33282763}, issn = {2231-0762}, abstract = {OBJECTIVE: The objective of this study was to assess in vitro the antibacterial efficacy of Ca(OH)2 with iodoform versus Ca(OH)2 with camphorated paramonochlorophenol as intrachannel pastes on an Enterococcus faecalis biofilm.

MATERIALS AND METHODS: The diffusion method was used in wells. The strain used was E. faecalis ATCC 29212. Bile esculin agar was inoculated into 60-well plates of 5 mm in diameter. Three groups were formed: Group 1: Calen PMCC (Ca(OH)2 + camphor paramonochlorophenol); Group 2: Metapex (Ca(OH)2 + iodoform); and Group 3: camphor paramonochlorophenol inoculated with E. faecalis as a positive control. The plates were then incubated at 37°C for 24 h. Bacterial inhibition halos were read.

RESULTS: Group 1 presented the highest antimicrobial efficacy with a mean of 16.2 ± 0.6 mm, whereas Group 2 only had an antimicrobial effect of 9.7 ± 1.3 mm. Finally, Group 3 only exposed to the positive control (camphor paramonochlorophenol) showed an effect of 14.6 ± 1.0 mm. The inferential analysis showed statistically significant differences between the antimicrobial effect of the three groups (P = 0.001).

CONCLUSION: Ca(OH)2 paste with camphor paramonochlorophenol (Calen PMCC) has a greater antibacterial action on E. faecalis. The iodoform-associated Ca(OH)2 paste (Metapex) showed significantly lower antibacterial action against E. faecalis (P < 0.05).}, } @article {pmid33281751, year = {2020}, author = {Irie, Y and La Mensa, A and Murina, V and Hauryliuk, V and Tenson, T and Shingler, V}, title = {Hfq-Assisted RsmA Regulation Is Central to Pseudomonas aeruginosa Biofilm Polysaccharide PEL Expression.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {482585}, pmid = {33281751}, issn = {1664-302X}, abstract = {To appropriately switch between sessile and motile lifestyles, bacteria control expression of biofilm-associated genes through multiple regulatory elements. In Pseudomonas aeruginosa, the post-transcriptional regulator RsmA has been implicated in the control of various genes including those related to biofilms, but much of the evidence for these links is limited to transcriptomic and phenotypic studies. RsmA binds to target mRNAs to modulate translation by affecting ribosomal access and/or mRNA stability. Here, we trace a global regulatory role of RsmA to inhibition of the expression of Vfr-a transcription factor that inhibits transcriptional regulator FleQ. FleQ directly controls biofilm-associated genes that encode the PEL polysaccharide biosynthesis machinery. Furthermore, we show that RsmA alone cannot bind vfr mRNA but requires the assistance of RNA chaperone protein Hfq. This is the first example where a RsmA protein family member requires another protein for binding to its target RNA.}, } @article {pmid33280848, year = {2021}, author = {Li, X and Lu, Y and Luo, H and Liu, G and Torres, CI and Zhang, R}, title = {Effect of pH on bacterial distributions within cathodic biofilm of the microbial fuel cell with maltodextrin as the substrate.}, journal = {Chemosphere}, volume = {265}, number = {}, pages = {129088}, doi = {10.1016/j.chemosphere.2020.129088}, pmid = {33280848}, issn = {1879-1298}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Hydrogen-Ion Concentration ; Polysaccharides ; }, abstract = {The aim of this study was to investigate pH effect on stratification of bacterial community in cathodic biofilm of the microbial fuel cell (MFC) under alkaline conditions. A single-chamber MFC with air-cathode was operated with 0.8 g/L maltodextrin and bicarbonate buffer solutions under pH values of 8.5, 9.5, and 10.5, respectively. The cathodic biofilms were characterized by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), confocal laser scanning microscopy (CLSM), freezing microtome and high-throughput sequencing analysis on bacterial communities, respectively. Results showed that the maximum power densities in the MFC increased with the pH values and reached 1221 ± 96 mW/m[2] at pH = 10.5 during ∼30 d of operation. With different pH values, the composition and relative abundance of bacterial community significantly changed in the bottom (0-50 μm), middle (50-100 μm), and top (100-150 μm) layers of the cathodic biofilm. With pH = 10.5, aerobic bacteria accounted for 12%, 13%, and 34% of the bacterial community in the top, middle, and bottom layers, respectively. The amount of anaerobic bacteria in the top and middle layers (i.e., 52%, and 50% of the bacterial community, respectively) was higher than that in the bottom layer (22%). The distribution of aerobic and anaerobic bacteria showed a "valley-peak" structure within the layers. The high CO3[2-] concentration facilitates the hydroxyl transfer and the neutralization in the anode of the MFC under high alkali conditions. The results from this study should be useful to develop new catalyst and cathode in the MFC.}, } @article {pmid33279072, year = {2021}, author = {Montso, PK and Mlambo, V and Ateba, CN}, title = {Efficacy of novel phages for control of multi-drug resistant Escherichia coli O177 on artificially contaminated beef and their potential to disrupt biofilm formation.}, journal = {Food microbiology}, volume = {94}, number = {}, pages = {103647}, doi = {10.1016/j.fm.2020.103647}, pmid = {33279072}, issn = {1095-9998}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteriophages/genetics/*physiology ; Biofilms ; Cattle ; Coliphages/genetics/*physiology ; Drug Resistance, Multiple, Bacterial ; Escherichia coli/drug effects/growth & development/*physiology/*virology ; Food Preservation/*methods ; Meat/*microbiology ; }, abstract = {Contaminated beef is a prominent source of foodborne pathogens such as Escherichia coli O177. Susceptibility of nine multi-drug resistant E. coli O177 strains against eight individual phages and six phage cocktails was assessed using polystyrene microplate titer plate. Further, 180 beef samples were independently inoculated with E. coli O177 cells in triplicates and treated with eight individual phages and six phage cocktails to determine their efficacy in inhibiting bacteria growth at 4 °C over a 7-day incubation period. Results revealed that all E. coli O177 strains were susceptible to the phages. A significant log reduction in viable E. coli O177 cell counts was observed on beef samples upon phage treatment over the 7-day incubation period. Two individual phages and three phage cocktails reduced E. coli cell counts to levels below the detection limit (1.0 log10 CFU/g). Log reduction of viable E. coli cell counts ranged from 2.10 to 7.81 CFU/g for individual phages and from 2.86 to 7.81 CFU/g for cocktails. Individual phages and phage cocktails inhibited E. coli O177 biofilm formation with phage cocktails showing high efficacy. Furthermore, phage cocktails showed greater efficacy in destroying pre-formed biofilm than individual phages. Based on these findings, we concluded that phage cocktails developed in this study could be used to reduce E. coli O177 contamination and extend the shelf-life of stored raw beef.}, } @article {pmid33279070, year = {2021}, author = {Pontin, KP and Borges, KA and Furian, TQ and Carvalho, D and Wilsmann, DE and Cardoso, HRP and Alves, AK and Chitolina, GZ and Salle, CTP and Moraes, HLS and do Nascimento, VP}, title = {Antimicrobial activity of copper surfaces against biofilm formation by Salmonella Enteritidis and its potential application in the poultry industry.}, journal = {Food microbiology}, volume = {94}, number = {}, pages = {103645}, doi = {10.1016/j.fm.2020.103645}, pmid = {33279070}, issn = {1095-9998}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Copper/analysis/*pharmacology ; Disinfectants/*pharmacology ; Equipment Contamination/prevention & control ; Food Handling/*instrumentation ; Poultry ; Salmonella enteritidis/*drug effects/growth & development/physiology ; Stainless Steel/analysis ; Zinc/analysis ; }, abstract = {As a consequence of developing antimicrobial resistance to disinfectants, copper, which exhibits antimicrobial activity, has been studied as a possible alternative to the use of stainless steel surfaces. The aim was to evaluate the antimicrobial activity of copper surfaces in preventing biofilm formation by Salmonella Enteritidis and to determine their corrosive capacity. Strains of S. Enteritidis were incubated at 4 °C, 12 °C, and 25 °C with 1 cm[2] coupons of electrolytic copper (99.9% Cu), brass (70% Cu), copper coated with tin, and stainless steel (control). A planktonic cell-suspension assay was used, followed by serial dilutions and bacterial counts. The corrosion test was performed with two disinfectants: benzalkonium chloride and sodium hypochlorite (100, 200, and 400 ppm). There was a significant reduction in biofilm production (log10 CFU cm[-2]) on the copper (2.64 at 4 °C, 4.20 at 12 °C, 4.56 at 25 °C) and brass (2.79 at 4 °C, 3.49 at 12 °C, 4.55 at 25 °C) surfaces compared to the control (5.68 at 4 °C, 5.89 at 12 °C, 6.01 at 25 °C). The antimicrobial surfaces showed uniform corrosion similar to that of surfaces generally used. These results demonstrated the effectiveness of copper surfaces in reducing S. Enteritidis and suggest they can be used as a complementary antimicrobial to control for this pathogen.}, } @article {pmid33278803, year = {2021}, author = {Machado, CB and Rocha da Silva, C and Daiana Barroso, F and Campos, RDS and Valente Sá, LGDA and S Aires do Nascimento, FB and Cavalcanti, BC and Vitoriano Nobre Júnior, H and Andrade Neto, JB}, title = {In vitro evaluation of anti-fungal activity of tropicamide against strains of Candida spp. resistant to fluconazole in planktonic and biofilm form.}, journal = {Journal de mycologie medicale}, volume = {31}, number = {1}, pages = {101080}, doi = {10.1016/j.mycmed.2020.101080}, pmid = {33278803}, issn = {1773-0449}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida/classification/*drug effects ; Drug Resistance, Fungal ; Fluconazole/pharmacology ; Humans ; Microbial Sensitivity Tests ; Tropicamide/*pharmacology ; }, abstract = {Candida spp. is considered to be the third or fourth most common cause of bloodstream infections associated with healthcare services in the world. Currently, several strains exhibit resistance to the traditional treatments, making the development of new therapeutic molecules necessary. Drug repositioning is an alternative that can be used to work around problems such as toxicity, cost and time in the development of new drugs. This study aims to evaluate the in vitro antifungal effect of tropicamide, molecule of anticholinergic action, against planktonic cells of Candida spp. and biofilm of C. albicans. Six strains of different Candida species were used to determine the minimum inhibitory concentration (MIC) of tropicamide and fluconazole according to CLSI document M27-A3 and one strain of C. albicans was used to evaluate the activity of tropicamide against biofilms. In concentrations of 64μg/mL, the tropicamide exhibited 50% of inhibitory activity in planktonic cell and in concentrations of 128μg/mL is able to inhibit the formation of C. albicans biofilm. Despite the inhibitory activity shown at the present study, the use of a larger number of strains, as well as in vivo cytotoxicity assays, is necessary to confirm the hypothesis that tropicamide can be used as an adjuvant agent in the treatment of infections by the Candida genus.}, } @article {pmid33277548, year = {2020}, author = {Nakamura, K and O'Neill, AM and Williams, MR and Cau, L and Nakatsuji, T and Horswill, AR and Gallo, RL}, title = {Short chain fatty acids produced by Cutibacterium acnes inhibit biofilm formation by Staphylococcus epidermidis.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {21237}, pmid = {33277548}, issn = {2045-2322}, support = {K12 GM068524/GM/NIGMS NIH HHS/United States ; R01 AR076082/AR/NIAMS NIH HHS/United States ; R01AI53185/NH/NIH HHS/United States ; R37 AI052453/AI/NIAID NIH HHS/United States ; R01 AI153185/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacillus subtilis/drug effects/physiology ; Biofilms/*drug effects ; Culture Media, Conditioned/analysis/pharmacology ; Drug Synergism ; Fatty Acids, Volatile/*pharmacology ; Hemiterpenes/pharmacology ; Isobutyrates/pharmacology ; Pentanoic Acids/pharmacology ; Polysaccharides/biosynthesis ; Propionates/pharmacology ; Propionibacteriaceae/*metabolism ; Pseudomonas aeruginosa/drug effects/physiology ; Staphylococcus aureus/drug effects/physiology ; Staphylococcus epidermidis/*drug effects/genetics/metabolism/physiology ; }, abstract = {Biofilm formation by bacterial pathogens is associated with numerous human diseases and can confer resistance to both antibiotics and host defenses. Many strains of Staphylococcus epidermidis are capable of forming biofilms and are important human pathogens. Since S. epidermidis coexists with abundant Cutibacteria acnes on healthy human skin and does not typically form a biofilm in this environment, we hypothesized that C. acnes may influence biofilm formation of S. epidermidis. Culture supernatants from C. acnes and other species of Cutibacteria inhibited S. epidermidis but did not inhibit biofilms by Pseudomonas aeruginosa or Bacillus subtilis, and inhibited biofilms by S. aureus to a lesser extent. Biofilm inhibitory activity exhibited chemical properties of short chain fatty acids known to be produced from C. acnes. The addition of the pure short chain fatty acids propionic, isobutyric or isovaleric acid to S. epidermidis inhibited biofilm formation and, similarly to C. acnes supernatant, reduced polysaccharide synthesis by S. epidermidis. Both short chain fatty acids and C. acnes culture supernatant also increased sensitivity of S. epidermidis to antibiotic killing under biofilm-forming conditions. These observations suggest the presence of C. acnes in a diverse microbial community with S. epidermidis can be beneficial to the host and demonstrates that short chain fatty acids may be useful to limit formation of a biofilm by S. epidermidis.}, } @article {pmid33275636, year = {2020}, author = {Sauvat, L and Abdul Hamid, AI and Blavignac, C and Josse, J and Lesens, O and Gueirard, P}, title = {Biofilm-coated microbeads and the mouse ear skin: An innovative model for analysing anti-biofilm immune response in vivo.}, journal = {PloS one}, volume = {15}, number = {12}, pages = {e0243500}, pmid = {33275636}, issn = {1932-6203}, mesh = {Animals ; Biofilms/*growth & development ; Cell Movement ; Disease Models, Animal ; Ear Auricle/immunology/microbiology/*pathology ; Female ; Fluorescent Dyes/chemistry ; Immunity, Innate ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Microscopy, Confocal ; Microspheres ; Phagocytes/cytology/immunology/*pathology ; Silicon Dioxide/chemistry ; Staphylococcal Infections/*immunology/pathology ; Staphylococcus aureus/*pathogenicity ; Time-Lapse Imaging ; }, abstract = {Owing to its ability to form biofilms, Staphylococcus aureus is responsible for an increasing number of infections on implantable medical devices. The aim of this study was to develop a mouse model using microbeads coated with S. aureus biofilm to simulate such infections and to analyse the dynamics of anti-biofilm inflammatory responses by intravital imaging. Scanning electron microscopy and flow cytometry were used in vitro to study the ability of an mCherry fluorescent strain of S. aureus to coat silica microbeads. Biofilm-coated microbeads were then inoculated intradermally into the ear tissue of LysM-EGFP transgenic mice (EGFP fluorescent immune cells). General and specific real-time inflammatory responses were studied in ear tissue by confocal microscopy at early (4-6h) and late time points (after 24h) after injection. The displacement properties of immune cells were analysed. The responses were compared with those obtained in control mice injected with only microbeads. In vitro, our protocol was capable of generating reproducible inocula of biofilm-coated microbeads verified by labelling matrix components, observing biofilm ultrastructure and confirmed in vivo and in situ with a matrix specific fluorescent probe. In vivo, a major inflammatory response was observed in the mouse ear pinna at both time points. Real-time observations of cell recruitment at injection sites showed that immune cells had difficulty in accessing biofilm bacteria and highlighted areas of direct interaction. The average speed of cells was lower in infected mice compared to control mice and in tissue areas where direct contact between immune cells and bacteria was observed, the average cell velocity and linearity were decreased in comparison to cells in areas where no bacteria were visible. This model provides an innovative way to analyse specific immune responses against biofilm infections on medical devices. It paves the way for live evaluation of the effectiveness of immunomodulatory therapies combined with antibiotics.}, } @article {pmid33274280, year = {2020}, author = {Hou, Z and Wu, Y and Xu, C and Reghu, S and Shang, Z and Chen, J and Pranantyo, D and Marimuth, K and De, PP and Ng, OT and Pethe, K and Kang, ET and Li, P and Chan-Park, MB}, title = {Precisely Structured Nitric-Oxide-Releasing Copolymer Brush Defeats Broad-Spectrum Catheter-Associated Biofilm Infections In Vivo.}, journal = {ACS central science}, volume = {6}, number = {11}, pages = {2031-2045}, pmid = {33274280}, issn = {2374-7943}, abstract = {Gram-negative bacteria cannot be easily eradicated by antibiotics and are a major source of recalcitrant infections of indwelling medical devices. Among various device-associated infections, intravascular catheter infection is a leading cause of mortality. Prior approaches to surface modification, such as antibiotics impregnation, hydrophilization, unstructured NO-releasing, etc., have failed to achieve adequate infection-resistant coatings. We report a precision-structured diblock copolymer brush (H(N)-b-S) composed of a surface antifouling block of poly(sulfobetaine methacrylate) (S) and a subsurface bactericidal block (H(N)) of nitric-oxide-emitting functionalized poly(hydroxyethyl methacrylate) (H) covalently grafted from the inner and outer surfaces of a polyurethane catheter. The block copolymer architecture of the coating is important for achieving good broad-spectrum anti-biofilm activity with good biocompatibility and low fouling. The coating procedure is scalable to clinically useful catheter lengths. Only the block copolymer brush coating ((H(N)-b-S)) shows unprecedented, above 99.99%, in vitro biofilm inhibition of Gram-positive and Gram-negative bacteria, 100-fold better than previous coatings. It has negligible toxicity toward mammalian cells and excellent blood compatibility. In a murine subcutaneous infection model, it achieves >99.99% biofilm reduction of Gram-positive and Gram-negative bacteria compared with <90% for silver catheter, while in a porcine central venous catheter infection model, it achieves >99.99% reduction of MRSA with 5-day implantation. This precision coating is readily applicable for long-term biofilm-resistant and blood-compatible copolymer coatings covalently grafted from a wide range of medical devices.}, } @article {pmid33273563, year = {2020}, author = {Hu, WS and Min Nam, D and Kim, JS and Koo, OK}, title = {Synergistic anti-biofilm effects of Brassicaceae plant extracts in combination with proteinase K against Escherichia coli O157:H7.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {21090}, pmid = {33273563}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Brassicaceae/*chemistry ; Drug Synergism ; Endopeptidase K/*pharmacology ; Escherichia coli/*drug effects/physiology ; Plant Extracts/*pharmacology ; Stainless Steel ; }, abstract = {Bacteria can form biofilms, complex microbial communities protected from environmental stress, on food contact surfaces. Brassicaceae plant has been shown to contain bioactive compounds with antimicrobial activities. The objective of this study was to evaluate the synergistic effects of Brassicaceae species and proteinase K against E. coli O157:H7 biofilm. We determined the minimum biofilm inhibitory concentration, the fractional inhibitory concentration indexes, and the synergistic inhibitory effect of Raphanus sativus var. longipinnatus, R. sativus, and Brassica oleracea var. acephala extracts with proteinase K on E. coli O157:H7. The biofilm showed a 49% reduction with 2 mg/mL R. sativus. The combination of proteinase K 25 µg/mL significantly increased the effect of 2 mg/mL R. sativus var. longipinnatus and the combined treatment yielded up to 2.68 log reduction on stainless steel coupons. The results showed that the combination of R. sativus var. longipinnatus extract and proteinase K could serve as an anti-biofilm agent with synergistic effects for inhibiting E. coli O157:H7 biofilm on stainless steel surfaces.}, } @article {pmid33272669, year = {2021}, author = {Wang, J and Jiang, Z and Wang, W and Wang, H and Zhang, Y and Wang, Y}, title = {The connection between aeration regimes and EPS composition in nitritation biofilm.}, journal = {Chemosphere}, volume = {265}, number = {}, pages = {129141}, doi = {10.1016/j.chemosphere.2020.129141}, pmid = {33272669}, issn = {1879-1298}, mesh = {*Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; Sewage ; }, abstract = {The effects of aeration regimes (intermittent and continuous aeration) on nitritation performance and biofilm EPS composition were evaluated in moving bed biofilm reactors (MBBRs), and a hypothesis that the aeration regimes affect EPS composition by affecting the microbial activity and sludge discharge content was proposed. The effluent NO2[-]/NH4[+] ratio corresponded to that of an anammox reaction (1.07 ± 0.20) for the MBBR with continuous aeration (MBBRcon.), while that in the MBBR with intermittent aeration (20 min on/15 min off) (MBBRint.) was relatively lower (0.75 ± 0.19). Furthermore, the activity of ammonia-oxidizing bacteria in MBBRcon. was 0.4-7.9 mg-N·L[-1]·h[-1] more than that in MBBRint., which was consistent with the lower proportion of dead cells in MBBRcon. compared with MBBRint. (9.4% vs. 31.8%). The higher microbial activity in MBBRcon. led to more sludge discharge than MBBRint., which was reflected in the higher biofilm detachment rate in MBBRcon. compared with MBBRint. (0.15 ± 0.02 vs. 0.11 ± 0.02 g m[-2]·d[-1]). The ratio of humic substances to polysaccharides in the EPS was high (0.96 ± 0.08) in the detachment biomass, while the ratios in the nitritation biofilm on carriers from MBBRcon. and MBBRint. were 0.52 ± 0.13 and 0.72 ± 0.16, respectively. We hypothesized that biofilm matrix with high ratios of humic substances to polysaccharides are structurally unstable and prone to fall off. In addition, the higher proportion of dead cells in MBBRint. made the proportion of humic substances in EPS high. Meanwhile, less sludge discharge in MBBRint. than MBBRcon. caused more humic substances to accumulate in the biofilm. These was responsible for the higher ratio of humic substances to polysaccharides in MBBRint. compared with MBBRcon. The findings elucidate the connection between aeration regimes and biofilm EPS composition, and guide the choice of aeration regimes in the design of biofilm reactors for partial nitritation.}, } @article {pmid33272602, year = {2021}, author = {Yan, Y and Wang, X and Askari, A and Lee, HS}, title = {A modelling study of the spatially heterogeneous mutualism between electroactive biofilm and planktonic bacteria.}, journal = {The Science of the total environment}, volume = {759}, number = {}, pages = {143537}, doi = {10.1016/j.scitotenv.2020.143537}, pmid = {33272602}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; Electrodes ; *Plankton ; *Symbiosis ; }, abstract = {Microbial cooperation widely exists in anaerobic reactors degrading complex pollutants, conventionally studied separately inside the biofilm or the planktonic community. Recent experiments discovered the mutualism between the planktonic bacteria and electroactive biofilm treating propionate, an end-product usually accumulated in anaerobic digesters. Here, a one-dimensional multispecies model found the preference on acetate-based pathway over the hydrogen-based in such community, evidenced by the fact that acetate-originated current takes 66% of the total value and acetate-consuming anode-respiring bacteria takes over 80% of the biofilm. Acetate-based anodic respiration most apparently influences biofilm function while propionate fermentation is the dominant planktonic bio-reaction. Additionally, initial planktonic propionate level shows the ability of coordinating the balance between these two extracellular electron transfer pathways. Increasing the propionate concentration from 2 to 50 mM would increase the steady hydrogen-originated current by 210% but decrease the acetate-originated by 26%, suggesting a vital influence of the planktonic microbial process to the metabolic balance in biofilm. Best strategy to promote the biofilm activity is to increase the biomass density and biofilm conductivity simultaneously, which would increase the current density by 875% without thickening the biofilm thickness or prolonging the growth apparently.}, } @article {pmid33272177, year = {2021}, author = {Moghadam, MT and Chegini, Z and Khoshbayan, A and Farahani, I and Shariati, A}, title = {Helicobacter pylori Biofilm and New Strategies to Combat it.}, journal = {Current molecular medicine}, volume = {21}, number = {7}, pages = {549-561}, doi = {10.2174/1566524020666201203165649}, pmid = {33272177}, issn = {1875-5666}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; *Helicobacter Infections/drug therapy/metabolism ; Helicobacter pylori/*physiology ; Humans ; *Lymphoma, B-Cell, Marginal Zone/drug therapy/metabolism/microbiology ; *Persistent Infection/drug therapy/metabolism/microbiology ; *Stomach Neoplasms/drug therapy/metabolism/microbiology ; }, abstract = {Helicobacter pylori, the most frequent pathogen worldwide that colonizes around 50% of the world's population, causes important diseases such as gastric adenocarcinoma, chronic gastritis, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In recent years, various studies have reported that H. pylori biofilm may be one of the critical barriers to the eradication of this bacterial infection. Biofilms inhibit the penetration of antibiotics, increase the expression of efflux pumps and mutations, multiple therapeutic failures, and chronic infections. Nanoparticles and natural products can demolish H. pylori biofilm by destroying the outer layers and inhibiting the initial binding of bacteria. Also, the use of combination therapies destroying extracellular polymeric substances decreases coccoid forms of bacteria and degrading polysaccharides in the outer matrix that lead to an increase in the permeability and performance of antibiotics. Different probiotics, antimicrobial peptides, chemical substances, and polysaccharides by inhibiting adhesion and colonization of H. pylori can prevent biofilm formation by this bacterium. Of note, many of the above are applicable to acidic pH and can be used to treat gastritis. Therefore, H. pylori biofilm may be one of the major causes of failure to eradication of infections caused by this bacterium, and antibiotics are not capable of destroying the biofilm. Thus, it is necessary to use new strategies to prevent recurrent and chronic infections by inhibiting biofilm formation.}, } @article {pmid33271284, year = {2021}, author = {Ikeda, K and Yanase, Y and Hayashi, K and Hara-Kudo, Y and Tsuji, G and Demizu, Y}, title = {Amine skeleton-based c-di-GMP derivatives as biofilm formation inhibitors.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {32}, number = {}, pages = {127713}, doi = {10.1016/j.bmcl.2020.127713}, pmid = {33271284}, issn = {1464-3405}, mesh = {Amines/*chemistry ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cyclic GMP/*analogs & derivatives/chemistry/pharmacology ; Gram-Negative Bacteria/physiology ; Gram-Positive Bacteria/physiology ; }, abstract = {Bacteria can form a biofilm composed of diverse bacterial microorganism, which work as a barrier to protect from threats, such as antibiotics and host immunity system. The formation of biofilms significantly impairs the efficacy of antibiotics against pathogenic bacteria. It is also a serious problem to be solved that the emergence of multidrug-resistant bacteria (such as methicillin-resistant Staphylococcus aureus, MRSA) accelerated by the overuse of antibiotics. Therefore, the usage of biofilm inhibition agents has attracted immense interest as a novel strategy for treatment of diseases related to bacterial infection. From the difference of mode of action against bacterial cells, biofilm inhibition agents are expected to circumvent the emergence of multidrug-resistant bacteria. In this study, we have developed the derivatives of c-di-GMP, a kind of cyclic dinucleotide that is expected to have the effect of inhibiting bacterial biofilm formation. Some of the synthesized derivatives were found to inhibit biofilm formation of Gram-positive bacteria.}, } @article {pmid33270697, year = {2020}, author = {Kosztołowicz, T and Metzler, R and Wa Sik, S and Arabski, M}, title = {Modelling experimentally measured of ciprofloxacin antibiotic diffusion in Pseudomonas aeruginosa biofilm formed in artificial sputum medium.}, journal = {PloS one}, volume = {15}, number = {12}, pages = {e0243003}, pmid = {33270697}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacokinetics ; Biofilms/drug effects ; Ciprofloxacin/*pharmacokinetics ; Diffusion ; Models, Biological ; Pseudomonas aeruginosa/*drug effects ; Sputum/chemistry/*microbiology ; }, abstract = {We study the experimentally measured ciprofloxacin antibiotic diffusion through a gel-like artificial sputum medium (ASM) mimicking physiological conditions typical for a cystic fibrosis layer, in which regions occupied by Pseudomonas aeruginosa bacteria are present. To quantify the antibiotic diffusion dynamics we employ a phenomenological model using a subdiffusion-absorption equation with a fractional time derivative. This effective equation describes molecular diffusion in a medium structured akin Thompson's plumpudding model; here the 'pudding' background represents the ASM and the 'plums' represent the bacterial biofilm. The pudding is a subdiffusion barrier for antibiotic molecules that can affect bacteria found in plums. For the experimental study we use an interferometric method to determine the time evolution of the amount of antibiotic that has diffused through the biofilm. The theoretical model shows that this function is qualitatively different depending on whether or not absorption of the antibiotic in the biofilm occurs. We show that the process can be divided into three successive stages: (1) only antibiotic subdiffusion with constant biofilm parameters, (2) subdiffusion and absorption of antibiotic molecules with variable biofilm transport parameters, (3) subdiffusion and absorption in the medium but the biofilm parameters are constant again. Stage 2 is interpreted as the appearance of an intensive defence build-up of bacteria against the action of the antibiotic, and in the stage 3 it is likely that the bacteria have been inactivated. Times at which stages change are determined from the experimentally obtained temporal evolution of the amount of antibiotic that has diffused through the ASM with bacteria. Our analysis shows good agreement between experimental and theoretical results and is consistent with the biologically expected biofilm response. We show that an experimental method to study the temporal evolution of the amount of a substance that has diffused through a biofilm is useful in studying the processes occurring in a biofilm. We also show that the complicated biological process of antibiotic diffusion in a biofilm can be described by a fractional subdiffusion-absorption equation with subdiffusion and absorption parameters that change over time.}, } @article {pmid33269912, year = {2021}, author = {Soldano, A and Yao, H and Punchi Hewage, AND and Meraz, K and Annor-Gyamfi, JK and Bunce, RA and Battaile, KP and Lovell, S and Rivera, M}, title = {Small Molecule Inhibitors of the Bacterioferritin (BfrB)-Ferredoxin (Bfd) Complex Kill Biofilm-Embedded Pseudomonas aeruginosa Cells.}, journal = {ACS infectious diseases}, volume = {7}, number = {1}, pages = {123-140}, pmid = {33269912}, issn = {2373-8227}, support = {R01 AI125529/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins ; Biofilms ; Crystallography, X-Ray ; Cytochrome b Group ; *Ferredoxins ; Ferritins ; *Pseudomonas aeruginosa ; }, abstract = {Bacteria depend on a well-regulated iron homeostasis to survive adverse environments. A key component of the iron homeostasis machinery is the compartmentalization of Fe[3+] in bacterioferritin and its subsequent mobilization as Fe[2+] to satisfy metabolic requirements. In Pseudomonas aeruginosa Fe[3+] is compartmentalized in bacterioferritin (BfrB), and its mobilization to the cytosol requires binding of a ferredoxin (Bfd) to reduce the stored Fe[3+] and release the soluble Fe[2+]. Blocking the BfrB-Bfd complex in P. aeruginosa by deletion of the bfd gene triggers an irreversible accumulation of Fe[3+] in BfrB, concomitant cytosolic iron deficiency and significant impairment of biofilm development. Herein we report that small molecules developed to bind BfrB at the Bfd binding site block the BfrB-Bfd complex, inhibit the mobilization of iron from BfrB in P. aeruginosa cells, elicit a bacteriostatic effect on planktonic cells, and are bactericidal to cells embedded in mature biofilms.}, } @article {pmid33269803, year = {2020}, author = {Shepherd, J}, title = {Best served small: nano battles in the war against wound biofilm infections.}, journal = {Emerging topics in life sciences}, volume = {4}, number = {6}, pages = {567-580}, doi = {10.1042/ETLS20200155}, pmid = {33269803}, issn = {2397-8554}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Anti-Infective Agents ; Bacteria ; Biofilms ; Humans ; *Wound Infection/drug therapy ; }, abstract = {The global challenge of antimicrobial resistance is of increasing concern, and alternatives to currently used antibiotics or methods to improve their stewardship are sought worldwide. Microbial biofilms, complex 3D communities of bacteria and/or fungi, are difficult to treat with antibiotics for several reasons. These include their protective coats of extracellular matrix proteins which are difficult for antibiotics to penetrate. Nanoparticles (NP) are one way to rise to this challenge; whilst they exist in many forms naturally there has been a profusion in synthesis of these small (<100 nm) particles for biomedical applications. Their small size allows them to penetrate the biofilm matrix, and as well as some NP being inherently antimicrobial, they also can be modified by doping with antimicrobial payloads or coated to increase their effectiveness. This mini-review examines the current role of NP in treating wound biofilms and the rise in multifunctionality of NP.}, } @article {pmid33269552, year = {2021}, author = {Koyanagi, H and Kitamura, A and Nakagami, G and Kashiwabara, K and Sanada, H and Sugama, J}, title = {Local wound management factors related to biofilm reduction in the pressure ulcer: A prospective observational study.}, journal = {Japan journal of nursing science : JJNS}, volume = {18}, number = {2}, pages = {e12394}, doi = {10.1111/jjns.12394}, pmid = {33269552}, issn = {1742-7924}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Humans ; *Pressure Ulcer/prevention & control ; Prospective Studies ; Wound Healing ; }, abstract = {AIMS: Critical colonization in pressure ulcers delays healing and has been studied. However, local wound management includes no clear strategy for preventing the development of biofilms. Therefore, this multicenter, prospective, observational study was conducted to examine the effect of local management on the biofilm area of pressure ulcers with critical colonization.

METHODS: Participants were 34 patients with a pressure ulcer deeper than the dermis and in a state of critical colonization. The primary outcome was the change over a week in the proportion of the biofilm area in relation to that of the pressure ulcer area. We investigated the relationship between primary outcome and local wound management. The wound-blotting method was used for determining the biofilm area. To calculate the change in the biofilm area, baseline proportion was subtracted from proportion 1 week later.

RESULTS: Six types of topical treatment were used in three facilities. The proportion of the biofilm area at 1 week follow-up was significantly smaller with iodine ointment than that without iodine ointment (p = .02). The standardized partial regression coefficient of iodine ointment adjusted by the type of medical facility was -0.26 (p = .003).

CONCLUSION: This study revealed that the use of iodine ointment reduced the proportion of the biofilm area in the pressure ulcer surface. To manage pressure ulcers in a state of critical colonization, these results suggest that local management include the use of iodine ointment.}, } @article {pmid33268670, year = {2020}, author = {Yamabe, K and Arakawa, Y and Shoji, M and Onda, M and Miyamoto, K and Tsuchiya, T and Akeda, Y and Terada, K and Tomono, K}, title = {Direct anti-biofilm effects of macrolides on Acinetobacter baumannii: comprehensive and comparative demonstration by a simple assay using microtiter plate combined with peg-lid.}, journal = {Biomedical research (Tokyo, Japan)}, volume = {41}, number = {6}, pages = {259-268}, doi = {10.2220/biomedres.41.259}, pmid = {33268670}, issn = {1880-313X}, mesh = {Acinetobacter Infections/drug therapy/microbiology ; Acinetobacter baumannii/*drug effects/growth & development/metabolism ; Acyl-Butyrolactones/*antagonists & inhibitors/metabolism ; Agrobacterium tumefaciens/drug effects/growth & development/metabolism ; Anti-Bacterial Agents/*pharmacology ; Azithromycin/pharmacology ; Biofilms/*drug effects/growth & development ; Biological Assay ; Clarithromycin/pharmacology ; Erythromycin/pharmacology ; Fidaxomicin/pharmacology ; Humans ; Ivermectin/pharmacology ; Josamycin/pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Quorum Sensing/*drug effects ; Spiramycin/pharmacology ; }, abstract = {Recently, opportunistic nosocomial infections caused by Acinetobacter baumannii have become increasingly prevalent worldwide. The pathogen often establishes biofilms that adhere to medical devices, causing chronic infections refractory to antimicrobial therapy. Clinical reports have indicated that some macrolide antibiotics are effective against chronic biofilm-related infections. In this study, we examined the direct anti-biofilm effects of seven macrolides (azithromycin, clarithromycin, erythromycin, josamycin, spiramycin, fidaxomicin, and ivermectin) on A. baumannii using a simple and newly established in vitro assay system for the swift and serial spectrophotometric determinations of two biofilm-amount indexes of viability and biomass. These macrolides were found to possess direct anti-biofilm effects exerting specific anti-biofilm effects not exclusively depending on their bacteriostatic/bactericidal effects. The anti-biofilm effect of azithromycin was found to be the strongest, while those of fidaxomicin and ivermectin were weak and limited. These results provide insights into possible adjunctive chemotherapy with macrolides for A. baumannii infection. Common five macrolides also interfered with the Agrobacterium tumefaciens NTL(pCF218) (pCF372) bioassay system of N-acyl homoserine lactones, providing insights into sample preparation for the bioassay, and putatively suggesting the actions of macrolides as remote signals in bacterial quorum sensing systems.}, } @article {pmid33267882, year = {2020}, author = {Cunha, E and Rebelo, S and Carneiro, C and Tavares, L and Carreira, LM and Oliveira, M}, title = {A polymicrobial biofilm model for testing the antimicrobial potential of a nisin-biogel for canine periodontal disease control.}, journal = {BMC veterinary research}, volume = {16}, number = {1}, pages = {469}, pmid = {33267882}, issn = {1746-6148}, support = {SFRH/BD/131384/2017//Foundation for Science and Technology (FCT)/ ; }, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage ; Biofilms/*drug effects ; Dog Diseases/*drug therapy ; Dogs ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Nisin/*pharmacology ; Periodontal Diseases/drug therapy/microbiology/*veterinary ; }, abstract = {BACKGROUND: Periodontal disease (PD) in dogs is prompted by the establishment of a polymicrobial biofilm at the tooth surface and a subsequent host inflammatory response. Several strategies may be used for PD control, including dental hygiene home care procedures, like toothbrushing, special diet and chew toys that reduce dental plaque accumulation, or professional periodontal treatments. Aiming at PD control, a biogel composed by nisin and guar-gum was previously developed. This work aimed to establish an in vitro model mimicking the PD-associated biofilms and to evaluate the nisin-biogel inhibitory activity against this polymicrobial biofilm by determining its Minimum Biofilm Inhibitory (MBIC) and Eradication Concentrations (MBEC). Bacterial species tested included Neisseria zoodegmatis CCUG 52598T, Corynebacterium canis CCUG 58627T, Porphyromonas cangingivalis DSMZ VPB 4874, Peptostreptococcus canis CCUG 57081 and an Enterococcus faecalis isolate belonging to a collection of oral bacteria obtained from dogs with PD. Before establishing the biofilm, coaggregation between species was determined by optical density measurement after 2 and 24 hours. Nisin-biogel MBIC and MBEC values regarding the polymicrobial biofilm were determined using a modified version of the Calgary biofilm pin lid device, after confirming the presence of the five bacterial species by Fluorescent In Situ Hybridization.

RESULTS: Only 40% of the bacterial dual suspensions were able to coaggregate at 2 hours, but all species tested exhibited a coaggregation percentage higher than 30% at 24 hours. It was possible to establish a 48 h polymicrobial biofilm model composed by the five bacterial species selected. This model was used to determine nisin-biogel MBIC (26.39 ± 5.89 µg/mL) and MBEC (62.5 ± 27.73 µg/mL) values.

CONCLUSIONS: Our results showed that the nisin-biogel can inhibit and eradicate PD multispecies biofilms. As this in vitro model mimics an in vivo periodontal polymicrobial biofilm, our results reinforce the potential of the application of nisin-biogel for canine PD control.}, } @article {pmid33264398, year = {2020}, author = {Reuter, M and Ultee, E and Toseafa, Y and Tan, A and van Vliet, AHM}, title = {Inactivation of the core cheVAWY chemotaxis genes disrupts chemotactic motility and organised biofilm formation in Campylobacter jejuni.}, journal = {FEMS microbiology letters}, volume = {367}, number = {24}, pages = {}, doi = {10.1093/femsle/fnaa198}, pmid = {33264398}, issn = {1574-6968}, support = {BB/J004529/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Campylobacter jejuni/*genetics ; Chemotactic Factors/*genetics ; Chemotaxis/*genetics ; *Gene Silencing ; Mutation ; }, abstract = {Flagellar motility plays a central role in the bacterial foodborne pathogen Campylobacter jejuni, as flagellar motility is required for reaching the intestinal epithelium and subsequent colonisation or disease. Flagellar proteins also contribute strongly to biofilm formation during transmission. Chemotaxis is the process directing flagellar motility in response to attractant and repellent stimuli, but its role in biofilm formation of C. jejuni is not well understood. Here we show that inactivation of the core chemotaxis genes cheVAWY in C. jejuni strain NCTC 11168 affects both chemotactic motility and biofilm formation. Inactivation of any of the core chemotaxis genes (cheA, cheY, cheV or cheW) impaired chemotactic motility but did not affect flagellar assembly or growth. The ∆cheY mutant swam in clockwise loops, while complementation restored normal motility. Inactivation of the core chemotaxis genes interfered with the ability to form a discrete biofilm at the air-media interface, and the ∆cheY mutant displayed reduced dispersal/shedding of bacteria into the planktonic fraction. This suggests that while the chemotaxis system is not required for biofilm formation per se, it is necessary for organized biofilm formation. Hence interference with the Campylobacter chemotaxis system at any level disrupts optimal chemotactic motility and transmission modes such as biofilm formation.}, } @article {pmid33263649, year = {2020}, author = {Park, SH and Kim, OJ and Chung, HJ and Kim, OS}, title = {Effect of a Er, Cr:YSGG laser and a Er:YAG laser treatment on oral biofilm-contaminated titanium.}, journal = {Journal of applied oral science : revista FOB}, volume = {28}, number = {}, pages = {e20200528}, pmid = {33263649}, issn = {1678-7765}, mesh = {Biofilms ; *Dental Plaque ; Humans ; *Lasers, Solid-State/therapeutic use ; Microscopy, Electron, Scanning ; Titanium ; }, abstract = {OBJECTIVE: Implant surface decontamination is a challenging procedure for therapy of peri-implant disease. This study aimed to compare the effectiveness of decontamination on oral biofilm-contaminated titanium surfaces in Er:YAG laser, Er, Cr:YSGG laser, and plastic curette.

METHODOLOGY: For oral biofilms formation, six participants wore an acrylic splint with eight titanium discs in the maxillary arch for 72 hours. A total of 48 contaminated discs were distributed among four groups: untreated control; decontamination with plastic curettes; Er, Cr:YSGG laser; and Er:YAG laser irradiation. Complete plaque removal was estimated using naked-eye and the time taken was recorded; the residual plaque area was measured and the morphological alteration of the specimen surface was observed by scanning electron microscopy. The total bacterial load and the viability of adherent bacteria were quantified by live or dead cell labeling with fluorescence microscopy.

RESULTS: The mean treatment time significantly decreased based on the treatment used in the following order: Er:YAG, Er, Cr:YSGG laser, and plastic curettes (234.9±25.4 sec, 156.1±12.7 sec, and 126.4±18.6 sec, P=0.000). The mean RPA in the Er, Cr:YSGG laser group (7.0±2.5%) was lower than Er:YAG and plastic curettes groups (10.3±2.4%, 12.3±3.6%, p=0.023). The viable bacteria on the titanium surface after Er, Cr:YSGG laser irradiation was significantly lower compared to the decontamination with plastic curette (P=0.05) but it was not significantly different from the Er:YAG laser irradiation.

CONCLUSION: We found that Er:YAG laser and Er, Cr:YSGG laser irradiation were effective methods for decontaminations without surface alterations.}, } @article {pmid33260367, year = {2020}, author = {Mangal, U and Kwon, JS and Choi, SH}, title = {Bio-Interactive Zwitterionic Dental Biomaterials for Improving Biofilm Resistance: Characteristics and Applications.}, journal = {International journal of molecular sciences}, volume = {21}, number = {23}, pages = {}, pmid = {33260367}, issn = {1422-0067}, support = {NRF-2018R1C1B6000989//Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning/ ; Project Number: 202011D04//Korea Medical Device Development Fund grant funded by the Korea government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, Republic of Korea, the Ministry of Food and Drug Safety)/ ; }, mesh = {Bacterial Adhesion/drug effects ; Biocompatible Materials/*pharmacology ; Biofilms/*drug effects ; Dental Materials/*pharmacology ; Humans ; Mouth/microbiology ; Polymers/chemistry/pharmacology ; }, abstract = {Biofilms are formed on surfaces inside the oral cavity covered by the acquired pellicle and develop into a complex, dynamic, microbial environment. Oral biofilm is a causative factor of dental and periodontal diseases. Accordingly, novel materials that can resist biofilm formation have attracted significant attention. Zwitterionic polymers (ZPs) have unique features that resist protein adhesion and prevent biofilm formation while maintaining biocompatibility. Recent literature has reflected a rapid increase in the application of ZPs as coatings and additives with promising outcomes. In this review, we briefly introduce ZPs and their mechanism of antifouling action, properties of human oral biofilms, and present trends in anti-biofouling, zwitterionic, dental materials. Furthermore, we highlight the existing challenges in the standardization of biofilm research and the future of antifouling, zwitterated, dental materials.}, } @article {pmid33259287, year = {2020}, author = {Zaman, M and Andreasen, M}, title = {Cross-talk between individual phenol-soluble modulins in Staphylococcus aureus biofilm enables rapid and efficient amyloid formation.}, journal = {eLife}, volume = {9}, number = {}, pages = {}, pmid = {33259287}, issn = {2050-084X}, support = {AUFF-E-2017-7-16//Aarhus Universitets Forskningsfond/International ; }, mesh = {Amyloidogenic Proteins/chemistry/*metabolism ; Bacterial Proteins/chemistry/*metabolism ; Biofilms/*growth & development ; Kinetics ; Phenol/chemistry ; Protein Aggregates ; Protein Stability ; Protein Structure, Secondary ; Solubility ; Solvents/chemistry ; Staphylococcus aureus/growth & development/*metabolism/pathogenicity ; Structure-Activity Relationship ; Virulence Factors/chemistry/*metabolism ; }, abstract = {The infective ability of the opportunistic pathogen Staphylococcus aureus, recognized as the most frequent cause of biofilm-associated infections, is associated with biofilm-mediated resistance to host immune response. Phenol-soluble modulins (PSM) comprise the structural scaffold of S. aureus biofilms through self-assembly into functional amyloids, but the role of individual PSMs during biofilm formation remains poorly understood and the molecular pathways of PSM self-assembly are yet to be identified. Here we demonstrate high degree of cooperation between individual PSMs during functional amyloid formation. PSMα3 initiates the aggregation, forming unstable aggregates capable of seeding other PSMs resulting in stable amyloid structures. Using chemical kinetics we dissect the molecular mechanism of aggregation of individual PSMs showing that PSMα1, PSMα3 and PSMβ1 display secondary nucleation whereas PSMβ2 aggregates through primary nucleation and elongation. Our findings suggest that various PSMs have evolved to ensure fast and efficient biofilm formation through cooperation between individual peptides.}, } @article {pmid33255054, year = {2021}, author = {Passos, TF and Souza, MT and Zanotto, ED and de Souza, CWO}, title = {Bactericidal activity and biofilm inhibition of F18 bioactive glass against Staphylococcus aureus.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {118}, number = {}, pages = {111475}, doi = {10.1016/j.msec.2020.111475}, pmid = {33255054}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Staphylococcal Infections/drug therapy ; Staphylococcus aureus ; }, abstract = {Antimicrobial treatment failure has been increasing at alarming rates. In this context, the bactericidal properties of biocompatible antimicrobial agents have been widely studied. F18 is a recently developed bioactive glass that presents a much wider working range when compared to other bioactive glasses, a feature that allows it to be used for coating metallic implants, sintering scaffolds or manufacturing fibers for wound healing applications. The aim of this study was to investigate the in vitro bactericidal and anti-biofilm activity of F18 glass as a powder and as a coating on steel samples, and to explore the effects of its dissolution products at concentrations from 3 mg/mL to 50 mg/mL against the Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Furthermore, we intend to verify whether changes in the medium pH could influence the bactericidal activity of F18. The results indicated that F18 presented bactericidal activity in preformed S. aureus and MRSA biofilms, reducing more than 6 logs of the viable cells that remained in contact with 50 mg/mL for 24 h. Moreover, an anti-biofilm activity was observed after 12 h of direct contact, with a drop of more than 6 logs of the viable bacterial population. Neutralization of the F18 solution pH decreased its bactericidal efficacy. These results indicate that the F18 glass could be considered as an alternative material for controlling and treating infections by S. aureus.}, } @article {pmid33254968, year = {2021}, author = {Takamiya, AS and Monteiro, DR and Gorup, LF and Silva, EA and de Camargo, ER and Gomes-Filho, JE and de Oliveira, SHP and Barbosa, DB}, title = {Biocompatible silver nanoparticles incorporated in acrylic resin for dental application inhibit Candida albicans biofilm.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {118}, number = {}, pages = {111341}, doi = {10.1016/j.msec.2020.111341}, pmid = {33254968}, issn = {1873-0191}, mesh = {Acrylic Resins ; Animals ; Biofilms ; *Candida albicans ; Denture Bases ; *Metal Nanoparticles ; Rats ; Rats, Wistar ; Silver/pharmacology ; }, abstract = {BACKGROUND: Although silver nanoparticles (SNP) have proven antimicrobial activity against different types of microorganisms, the effect of SNP incorporation into acrylic resin to control Candida albicans biofilm formation aiming at the prevention of Candida-associated denture stomatitis has not yet been fully elucidated.

OBJECTIVES: This study aimed to evaluate the antimicrobial effect of an acrylic resin containing SNP on C. albicans biofilm growth, the flexural strength of this material and tissue reaction in the subcutaneous connective tissue of rats to SNP.

METHOD: SNP were synthesized through silver nitrate reduction by sodium citrate. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to verify the size and colloidal stability. SNP were added to acrylic resin monomer (Lucitone 550) at 0.05, 0.5 and 5 vol%. The antimicrobial effect against C. albicans (ATCC 10231) was investigated by the enumeration of colony-forming units (CFUs) and SEM. The three-point bending test was performed to analyze the flexural strength. Tissue reaction was evaluated after 7 and 60 days of implantation in the connective tissue of Wistar rats.

RESULTS: Spherical particles of 5 and 10 nm were obtained. SNP at 0.05 and 0.5% incorporated into acrylic resin was effective in reducing C. albicans biofilm growth (p < .001). SEM revealed that the material was able to disrupt C. albicans biofilm formation and did not reduce the flexural strength compared to control (p > .05). The inflammatory response observed 60 days after implantation SNP in the subcutaneous tissue was similar to control.

CONCLUSION: It was concluded that SNP addition at 0.05 and 0.5% into acrylic resin exhibited antimicrobial effects against C. albicans biofilm, did not interfere in the flexural strength and may be considered biocompatible.}, } @article {pmid33254393, year = {2021}, author = {Zhang, F and Yu, Y and Pan, C and Saleem, M and Wu, Y}, title = {Response of periphytic biofilm in water to estrone exposure: Phenomenon and mechanism.}, journal = {Ecotoxicology and environmental safety}, volume = {207}, number = {}, pages = {111513}, doi = {10.1016/j.ecoenv.2020.111513}, pmid = {33254393}, issn = {1090-2414}, mesh = {Biofilms/*drug effects/growth & development ; Cyanobacteria ; Estrone/*toxicity ; Extracellular Polymeric Substance Matrix ; Microbiota ; Water ; Water Pollutants, Chemical/*toxicity ; }, abstract = {The responses of pure strains to contaminant (i.e., estrone, E1) exposure have been widely studied. However, few studies about the responses of multispecies microbial aggregates (e.g., periphytic biofilm) to E1 exposure are available. In this study, the changes in physiological activity and community composition of periphytic biofilms before and after E1 exposure were investigated. The results showed that periphytic biofilms exhibited high adaptability to E1 exposure at a concentration of 0.5 mg L[-1] based on physiological results. The increase in productivity of extracellular polymeric substances (EPS) after exposure to E1 was the main factor preventing association between E1 and microbial cells. The increase in the activity of superoxide dismutase (SOD) and ATP enzyme activity and the change in the co-occurrence pattern of microbial communities (increasing the relative abundance of Xanthomonadaceae and Cryomorphacea) also protected biofilms from E1 exposure. However, exposure to a high concentration of E1 (>10 mg L[-1]) significantly decreased EPS productivity and metabolic activity due to the excessive accumulation of reactive oxygen species. In addition, the abundance of some sensitive species, such as Pseudanabaenaceae, decreased sharply at this concentration. Overall, this study highlighted the feasibility of periphytic biofilms to adapt to E1 exposure at low concentrations in aquatic environments.}, } @article {pmid33253904, year = {2021}, author = {Gómez-Junyent, J and Murillo, O and Yu, HH and Azad, MAK and Wickremasinghe, H and Rigo-Bonnin, R and Benavent, E and Ariza, J and Li, J}, title = {In vitro pharmacokinetics/pharmacodynamics of continuous ceftazidime infusion alone and in combination with colistin against Pseudomonas aeruginosa biofilm.}, journal = {International journal of antimicrobial agents}, volume = {57}, number = {2}, pages = {106246}, doi = {10.1016/j.ijantimicag.2020.106246}, pmid = {33253904}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/pharmacokinetics/*pharmacology ; Biofilms/*drug effects ; Ceftazidime/administration & dosage/pharmacokinetics/*pharmacology ; Colistin/administration & dosage/pharmacokinetics/*pharmacology ; Drug Synergism ; Drug Therapy, Combination ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; beta-Lactam Resistance ; }, abstract = {OBJECTIVES: The pharmacokinetics/pharmacodynamics of continuous infusion (CI) beta-lactams for Pseudomonas aeruginosa biofilm infections has not been defined. This study evaluated the efficacy of several dosage regimens of CI ceftazidime, with or without colistin, an antibiotic with a potential antibiofilm effect, against biofilm-embedded P. aeruginosa.

METHODS: Mature biofilms of the reference strain PAO1 and the clinical isolate HUB8 (both ceftazidime- and colistin-susceptible) were investigated over 54h using a dynamic CDC biofilm reactor. CI dosage regimens were ceftazidime monotherapy (4, 10, 20 and 40 mg/L), colistin monotherapy (3.50 mg/L), and combinations of colistin and ceftazidime (4 or 40 mg/L). Efficacy was evaluated by changes in log10colony-forming units (cfu)/mL and confocal microscopy.

RESULTS: At 54 h, the antibiofilm activity of ceftazidime monotherapies was slightly higher for ceftazidime 20 mg/L (-2.84 log10cfu/mL) and 40 mg/L (-3.05) against PAO1, but no differences were seen against HUB8. Ceftazidime-resistant colonies emerged with 4 mg/L regimens in both strains and with other regimens in PAO1. Colistin monotherapy had significant antibiofilm activity against HUB8 (-3.07), but lower activity against PAO1 (-1.12), and colistin-resistant strains emerged. Combinations of ceftazidime and colistin had higher antibiofilm activity at 54 h compared with each monotherapy, and prevented the emergence of resistance to both antibiotics; higher antibiofilm activity was observed with ceftazidime 40 mg/L plus colistin compared with ceftazidime 4 mg/L plus colistin (-4.19 vs. -3.10 PAO1; -4.71 vs. -3.44 HUB8).

CONCLUSIONS: This study demonstrated that, with %T>MIC=100%, CI ceftazidime displayed concentration-dependent antibiofilm activity against P. aeruginosa biofilm, particularly in combination with colistin. These results support the use of high-dosage regimens of CI ceftazidime with colistin against biofilm-associated infections with ceftazidime-susceptible P. aeruginosa.}, } @article {pmid33253855, year = {2021}, author = {Zhang, Y and He, X and Cheng, P and Li, X and Wang, S and Xiong, J and Li, H and Wang, Z and Yi, H and Du, H and Liu, J and Chen, H}, title = {Effects of a novel anti-biofilm peptide CRAMP combined with antibiotics on the formation of Pseudomonas aeruginosa biofilms.}, journal = {Microbial pathogenesis}, volume = {152}, number = {}, pages = {104660}, doi = {10.1016/j.micpath.2020.104660}, pmid = {33253855}, issn = {1096-1208}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; Colistin/pharmacology ; *Pseudomonas aeruginosa ; Quorum Sensing ; Virulence Factors ; }, abstract = {The remarkable ability of Pseudomonas aeruginosa to form biofilms renders antibiotic treatments inefficient and therefore causing a wide variety of chronic infections. The quorum sensing (QS) system in P. aeruginosa plays a role in the regulation of genes controlling virulence factors and biofilm formation, which may be an essential target for pharmacological intervention. The present study aimed to investigate the synergistic activity of sub-MIC concentrations of CRAMP (a cathelicidin-related antimicrobial peptide) with fourteen antibiotics against P. aeroginusa biofilms. Finally, CRAMP's best synergistic activity combined with colistin at 1/4 MIC was screened by the checkerboard method and the calculation of the synergetic coefficient. It was confirmed by experiments on 6-well plates, displaying the most significant biofilm formation inhibition % (91.05%, calculated by OD value of biofilm biomass) and the best bactericidal activity of biofilms (2.77-log10 decrease). These data correlate with the confocal laser scanning microscopy (CLSM) images obtained for the biofilm. The combination also down-regulated the expression of QS regulated genes, resulting in inhibitory effects on QS-regulated virulence phenotypes (pyocyanin and rhamnolipid). These results indicate that a proposed method of combination therapy of CRAMP with colistin has the potential to serve as a more effective therapy for P. aeruginosa biofilm infection.}, } @article {pmid33253080, year = {2020}, author = {Sweeney, E and Sabnis, A and Edwards, AM and Harrison, F}, title = {Effect of host-mimicking medium and biofilm growth on the ability of colistin to kill Pseudomonas aeruginosa.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {12}, pages = {1171-1180}, pmid = {33253080}, issn = {1465-2080}, support = {MR/P028225/1/MRC_/Medical Research Council/United Kingdom ; MR/N014103/1/MRC_/Medical Research Council/United Kingdom ; MR/R001898/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Animals ; Anti-Bacterial Agents/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Colistin/*pharmacology ; Culture Media/chemistry/*pharmacology ; Cystic Fibrosis/microbiology ; Drug Resistance, Bacterial ; Humans ; Lung/microbiology ; Microbial Sensitivity Tests ; Models, Biological ; Pseudomonas aeruginosa/*drug effects/physiology ; Sputum/chemistry ; Swine ; }, abstract = {In vivo biofilms cause recalcitrant infections with extensive and unpredictable antibiotic tolerance. Here, we demonstrate increased tolerance of colistin by Pseudomonas aeruginosa when grown in medium that mimics cystic fibrosis (CF) sputum versus standard medium in in vitro biofilm assays, and drastically increased tolerance when grown in an ex vivo CF model versus the in vitro assay. We used colistin conjugated to the fluorescent dye BODIPY to assess the penetration of the antibiotic into ex vivo biofilms and showed that poor penetration partly explains the high doses of drug necessary to kill bacteria in these biofilms. The ability of antibiotics to penetrate the biofilm matrix is key to their clinical success, but hard to measure. Our results demonstrate both the importance of reduced entry into the matrix in in vivo-like biofilm, and the tractability of using a fluorescent tag and benchtop fluorimeter to assess antibiotic entry into biofilms. This method could be a relatively quick, cheap and useful addition to diagnostic and drug development pipelines, allowing the assessment of drug entry into biofilms, in in vivo-like conditions, prior to more detailed tests of biofilm killing.}, } @article {pmid33252326, year = {2021}, author = {Chen, YC and Chen, FJ and Lee, CH}, title = {Effect of antifungal agents, lysozyme and human antimicrobial peptide LL-37 on clinical Candida isolates with high biofilm production.}, journal = {Journal of medical microbiology}, volume = {70}, number = {2}, pages = {}, doi = {10.1099/jmm.0.001283}, pmid = {33252326}, issn = {1473-5644}, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Antimicrobial Cationic Peptides ; Biofilms/*drug effects/growth & development ; Candida parapsilosis/*drug effects/isolation & purification ; Candida tropicalis/*drug effects/isolation & purification ; Caspofungin/pharmacology ; Cathelicidins/*pharmacology ; Drug Combinations ; Fluconazole/pharmacology ; Humans ; Muramidase/*pharmacology ; }, abstract = {Introduction. Candida species can form biofilms on tissues and medical devices, making them less susceptible to antifungal agents.Hypothesis/Gap Statement. Antifungal combination may be an effective strategy to fight against Candida biofilm.Aim. In this study, we investigated the in vitro activity of fluconazole, caspofungin and amphotericin B, alone and in combination, against 17 clinical Candida tropicalis and 6 Candida parapsilosis isolates with high biofilm formation. We also tested LL-37 and lysozyme for anti-biofilm activity against a selected C. tropicalis isolate.Methodology. Candida biofilms were prepared using the 96-well plate-based method. The minimum biofilm eradication concentrations were determined for single and combined antifungal drugs. The activity of LL-37 and lysozyme was determined by visual reading for planktonic cells and using the XTT assay for biofilms.Results. Under biofilm conditions, fluconazole plus caspofungin showed synergistic effects against 60.9% (14 of 23) of the tested isolates, including 70.6% of C. tropicalis [fractional inhibitory concentration index (FICI), 0.26-1.03] and 33.3% of C. parapsilosis (FICI, 0.04-2.03) isolates. Using this combination, no antagonism was observed. Amphotericin B plus caspofungin showed no effects against 78.3% (18 of 23) of the tested isolates. Amphotericin B plus fluconazole showed no effects against 65.2% (15 of 23) of the tested isolates and may have led to antagonism against 2 C. tropicalis and 2 C. parapsilosis isolates. LL-37 and lysozyme had no effect on biofilms of the selected C. tropicalis isolate.Conclusions. We found that fluconazole plus caspofungin led to a synergistic effect against C. tropicalis and C. parapsilosis biofilms. The efficacy of the antifungal combination therapies of the proposed schemes against biofilm-associated Candida infections requires careful and constant evaluation.}, } @article {pmid33251260, year = {2020}, author = {Feng, Z and El Hag, M and Qin, T and Du, Y and Chen, S and Peng, D}, title = {Residue L193P Mutant of RpoS Affects Its Activity During Biofilm Formation in Salmonella Pullorum.}, journal = {Frontiers in veterinary science}, volume = {7}, number = {}, pages = {571361}, pmid = {33251260}, issn = {2297-1769}, abstract = {The role of alternative sigma factor RpoS in regulating biofilm formation may differ in various Salmonella Pullorum strains. In this study, the biofilm-forming ability of two Salmonella Pullorum strains S6702 and S11923-3 were compared. The biofilm forming ability of S11923-3 was much stronger than that of S6702. After knocking out the rpoS gene, S11923-3ΔrpoS had significantly reduced biofilm while S6702ΔrpoS demonstrated similar biofilm compared with each parent strain. The analysis of RpoS sequences indicated two amino acid substitutions (L193P and R293C) between S6702 and S11923-3 RpoS. A complementation study confirmed that the expression of S11923-3 RpoS rather than S6702 RpoS could restore the biofilm-forming ability of ΔrpoS strains and the L193P mutation contributed to the restoration of the biofilm-forming ability. Further study indicated that RpoS with the L193P mutant had significantly improved expression level and binding activity to RNAP and csgD gene promoter, which increased the efficacy of the csgD gene promoter and biofilm-forming ability. Therefore, the L193P mutation of RpoS is critical for stronger biofilm formation of Salmonella Pullorum.}, } @article {pmid33250645, year = {2020}, author = {Alam, P and Alqahtani, AS and Mabood Husain, F and Tabish Rehman, M and Alajmi, MF and Noman, OM and El Gamal, AA and Al-Massarani, SM and Shavez Khan, M}, title = {Siphonocholin isolated from red sea sponge Siphonochalina siphonella attenuates quorum sensing controlled virulence and biofilm formation.}, journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society}, volume = {28}, number = {11}, pages = {1383-1391}, pmid = {33250645}, issn = {1319-0164}, abstract = {Increasing incidence of multi-drug resistant bacterial pathogens, especially in clinical settings, has been developed into a grave health situation. The drug resistance problem demands the necessity for alternative unique therapeutic policies. One such tactic is targeting the quorum sensing (QS) controlled virulence and biofilm production. In this study, we evaluated a marine steroid Siphonocholin (Syph-1) isolated from Siphonochalina siphonella against Chromobacterium violaceum (CV) 12472, Pseudomonas aeruginosa (PAO1), Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (BAA) for biofilm and pellicle formation inhibition, and anti-QS property. MIC of Syph-1 against MRSA, CV, PAO1 was found as 64 µg/mL and 256 µg/mL against BAA. At selected sub-MICs, Syph-1 significantly (P ≤ 0.05) decreased the production of QS regulated virulence functions of CV12472 (violacein) and PAO1 [elastase, total protease, pyocyanin, chitinase, exopolysaccharides, and swarming motility]. The Syph-1 significantly decreased (p = 0.005) biofilm formation ability of tested bacterial pathogens, at sub-MIC level (PAO1 > MRSA > CV > BAA) and pellicle formation in A. baumannii (at 128 µg/mL). Molecular docking and simulation results indicated that Siph-1 was bound at the active site of BfmR N-terminal domain with high affinity. This study highlights the anti-QS and anti-biofilm activity of Syph-1 against bacterial pathogens reflecting its broad spectrum anti-infective potential.}, } @article {pmid33249878, year = {2022}, author = {Rossi, C and Chaves-López, C and Serio, A and Casaccia, M and Maggio, F and Paparella, A}, title = {Effectiveness and mechanisms of essential oils for biofilm control on food-contact surfaces: An updated review.}, journal = {Critical reviews in food science and nutrition}, volume = {62}, number = {8}, pages = {2172-2191}, doi = {10.1080/10408398.2020.1851169}, pmid = {33249878}, issn = {1549-7852}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Humans ; *Oils, Volatile/pharmacology ; Quorum Sensing ; }, abstract = {Microbial biofilms represent a constant source of contamination in the food industry, being also a real threat for human health. In fact, most of biofilm-producing bacteria are becoming resistant to sanitizers, thus arousing the interest in natural alternatives to prevent biofilm formation on foods and food-contact surfaces. In particular, studies on biofilm control by essential oils (EOs) application are increasing, being EOs characterized by unique mixtures of compounds able to impair the mechanisms of biofilm development. This review reports the anti-biofilm properties of EOs in bacterial biofilm control (inhibition, removal and prevention of biofilm dispersion) on food-contact surfaces. The relationship between EOs effect and composition, concentration, involved bacteria, and surfaces is discussed, and the possible sites of action are also elucidated. The findings prove the high biofilm controlling capability of EOs through the regulation of genes and proteins implicated in motility, Quorum Sensing and exopolysaccharides (EPS) matrix. Moreover, incorporation in nanosized delivery systems, formulation of blends and combination of EOs with other strategies can increase their anti-biofilm activity. This review provides an overview of the current knowledge of the EOs effectiveness in controlling bacterial biofilm on food-contact surfaces, providing valuable information for improving EOs use as sanitizers in food industries.}, } @article {pmid33249681, year = {2021}, author = {Pereira, R and Dos Santos Fontenelle, RO and de Brito, EHS and de Morais, SM}, title = {Biofilm of Candida albicans: formation, regulation and resistance.}, journal = {Journal of applied microbiology}, volume = {131}, number = {1}, pages = {11-22}, doi = {10.1111/jam.14949}, pmid = {33249681}, issn = {1365-2672}, mesh = {Antifungal Agents/*pharmacology/therapeutic use ; *Biofilms/drug effects/growth & development ; Candida albicans/drug effects/pathogenicity/*physiology ; Candidiasis/drug therapy/microbiology/prevention & control ; *Drug Resistance, Fungal/drug effects ; Humans ; Virulence ; }, abstract = {Candida albicans is the most common human fungal pathogen, causing infections that range from mucous membranes to systemic infections. The present article provides an overview of C. albicans, with the production of biofilms produced by this fungus, as well as reporting the classes of antifungals used to fight such infections, together with the resistance mechanisms to these drugs. Candida albicans is highly adaptable, enabling the transition from commensal to pathogen due to a repertoire of virulence factors. Specifically, the ability to change morphology and form biofilms is central to the pathogenesis of C. albicans. Indeed, most infections by this pathogen are associated with the formation of biofilms on surfaces of hosts or medical devices, causing high morbidity and mortality. Significantly, biofilms formed by C. albicans are inherently tolerant to antimicrobial therapy, so the susceptibility of C. albicans biofilms to current therapeutic agents remains low. Therefore, it is difficult to predict which molecules will emerge as new clinical antifungals. The biofilm formation of C. albicans has been causing impacts on susceptibility to antifungals, leading to resistance, which demonstrates the importance of research aimed at the prevention and control of these clinical microbial communities.}, } @article {pmid33249255, year = {2021}, author = {Wuersching, SN and Huth, KC and Hickel, R and Kollmuss, M}, title = {Inhibitory effect of LL-37 and human lactoferricin on growth and biofilm formation of anaerobes associated with oral diseases.}, journal = {Anaerobe}, volume = {67}, number = {}, pages = {102301}, doi = {10.1016/j.anaerobe.2020.102301}, pmid = {33249255}, issn = {1095-8274}, mesh = {Antimicrobial Cationic Peptides/*pharmacology ; Bacteria, Anaerobic/*drug effects/growth & development ; Biofilms/*drug effects ; Dental Caries/drug therapy/microbiology ; Humans ; Lactoferrin/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability ; Oxygen/metabolism ; Periodontal Diseases/*drug therapy/microbiology ; Periodontitis/drug therapy/microbiology ; Cathelicidins ; }, abstract = {This study was conducted to evaluate the antimicrobial potential of the antimicrobial peptides (AMP) LL-37 and human Lactoferricin (LfcinH) on the planktonic growth and biofilm formation of oral pathogenic anaerobes related to caries and periodontitis. Multi-species bacterial suspensions of either facultative anaerobic bacteria (FAB: Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii) or obligate anaerobic bacteria (OAB: Veillonella parvula, Parvimonas micra, Fusobacterium nucleatum) were incubated with different concentrations of AMP solutions for 8 h. Planktonic growth was registered with an ATP-based cell viability assay for FAB and via plate counting for OAB. Biofilms were grown on ZrO2 discs for 4 days in a mixture of the multi-species bacterial suspensions and AMP solutions. Biofilm mass was quantified using a microtiter plate biofilm assay with crystal violet staining. An overall planktonic growth inhibition and biofilm mass reduction of FAB and OAB was registered for LL-37 and LfcinH. Significant inhibitory threshold concentrations of LL-37 were observed in all experiments (p < 0.0001). No significant threshold was observed for LfcinH. Biofilm mass of OAB was barely reduced by LfcinH. The complete mechanisms of the AMPs are not fully understood yet. While LL-37 shows promising features as potential therapeutic for biofilm-associated oral diseases, LfcinH seems unsuitable for this particular indication. For clinical AMP use, further investigations will be necessary.}, } @article {pmid33247364, year = {2021}, author = {Burtseva, O and Baulina, O and Zaytseva, A and Fedorenko, T and Chekanov, K and Lobakova, E}, title = {In vitro Biofilm Formation by Bioluminescent Bacteria Isolated from the Marine Fish Gut.}, journal = {Microbial ecology}, volume = {81}, number = {4}, pages = {932-940}, pmid = {33247364}, issn = {1432-184X}, mesh = {Animals ; Bacteria/genetics ; *Biofilms ; *Enterobacteriaceae ; Fimbriae, Bacterial ; }, abstract = {The internal surface of the animal gastrointestinal tract is covered by microbial biofilms. They play an important role in the development and functioning of the host organism and protect it against pathogens. Microbial communities of gastrointestinal biofilms are less elucidated than luminal microbiota. Therefore, the studies of biofilm formation by gastrointestinal microorganisms are a topical issue. For the first time, we report the formation of a biofilm in vitro by the strains of bioluminescent bacteria isolated from the intestines of marine fish. These bacteria exhibit co-aggregation and tend to attach to solid surfaces. The attachment of cells is accompanied by appearance of the pili. Then, we observed the formation of microcolonies and the production of extracellular polymer substances (EPSs) connecting bacterial cells into an integrated system. The presence of acidic polysaccharides is shown in the EPS when using the ruthenium red staining. Acidic polysaccharides in this matrix is a biochemical evidence of microbial biofilms. On the fibers of the polymer matrix, these bacteria form the "mushroom body"-type structures. Matured biofilms exhibit a specific three-dimensional architecture with pores and channels formed by cells and EPS. We also demonstrated the formation of a biofilm by binary culture of the luminous enterobacterium Kosakonia cowanii and a Gram-positive Macrococcus sp. The data obtained help to understand the role of these bacteria in the intestines of fish. They lead to a new study in the field of investigation of the intestinal microbiome of fish.}, } @article {pmid33247117, year = {2020}, author = {Hathroubi, S and Hu, S and Ottemann, KM}, title = {Genetic requirements and transcriptomics of Helicobacter pylori biofilm formation on abiotic and biotic surfaces.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {56}, pmid = {33247117}, issn = {2055-5008}, support = {R01 AI116946/AI/NIAID NIH HHS/United States ; S10 OD023528/OD/NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics ; Bacteriological Techniques ; Biofilms/*growth & development ; Cell Line ; Epithelial Cells/cytology/microbiology ; Gastric Mucosa/*cytology/microbiology ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; *Gene Regulatory Networks ; Helicobacter pylori/genetics/*physiology ; Humans ; *Mutation ; Phenotype ; Plastics ; Sequence Analysis, RNA ; }, abstract = {Biofilm growth is a widespread mechanism that protects bacteria against harsh environments, antimicrobials, and immune responses. These types of conditions challenge chronic colonizers such as Helicobacter pylori but it is not fully understood how H. pylori biofilm growth is defined and its impact on H. pylori survival. To provide insights into H. pylori biofilm growth properties, we characterized biofilm formation on abiotic and biotic surfaces, identified genes required for biofilm formation, and defined the biofilm-associated gene expression of the laboratory model H. pylori strain G27. We report that H. pylori G27 forms biofilms with a high biomass and complex flagella-filled 3D structures on both plastic and gastric epithelial cells. Using a screen for biofilm-defective mutants and transcriptomics, we discovered that biofilm cells demonstrated lower transcripts for TCA cycle enzymes but higher ones for flagellar formation, two type four secretion systems, hydrogenase, and acetone metabolism. We confirmed that biofilm formation requires flagella, hydrogenase, and acetone metabolism on both abiotic and biotic surfaces. Altogether, these data suggest that H. pylori is capable of adjusting its phenotype when grown as biofilm, changing its metabolism, and re-shaping flagella, typically locomotion organelles, into adhesive structures.}, } @article {pmid33246623, year = {2021}, author = {Qiao, Z and Chen, J and Zhou, Q and Wang, X and Shan, Y and Yi, Y and Liu, B and Zhou, Y and Lü, X}, title = {Purification, characterization, and mode of action of a novel bacteriocin BM173 from Lactobacillus crustorum MN047 and its effect on biofilm formation of Escherichia coli and Staphylococcus aureus.}, journal = {Journal of dairy science}, volume = {104}, number = {2}, pages = {1474-1483}, doi = {10.3168/jds.2020-18959}, pmid = {33246623}, issn = {1525-3198}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteriocins/*isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane Permeability/drug effects ; Escherichia coli/*physiology ; Food Preservatives ; Lactobacillus/*chemistry ; Microbial Sensitivity Tests ; Staphylococcus aureus/*physiology ; }, abstract = {There is an increasing demand for dairy products, but the presence of food-spoilage bacteria seriously affects the development of the dairy industry. Bacteriocins are considered to be a potential antibacterial or antibiofilm agent that can be applied as a preservative. In this study, bacteriocin BM173 was successfully expressed in the Escherichia coli expression system and purified by a 2-step method. Furthermore, it exhibited a broad-spectrum antibacterial activity, high thermal stability (121°C, 20 min), and broad pH stability (pH 3-11). Moreover, the minimum inhibitory concentration values of BM173 against E. coli ATCC 25922 and Staphylococcus aureus ATCC 25923 were 14.8 μg/mL and 29.6 μg/mL, respectively. Growth and time-kill curves showed that BM173 exhibited antibacterial and bactericidal activity. The results of scanning electron microscopy and transmission electron microscopy demonstrated that BM173 increased membrane permeability, facilitated pore formation, and even promoted cell lysis. The disruption of cell membrane integrity was further verified by propidium iodide uptake and lactic dehydrogenase release. In addition, BM173 exhibited high efficiency in inhibiting biofilm formation. Therefore, BM173 has promising potential as a preservative used in the dairy industry.}, } @article {pmid33246097, year = {2021}, author = {Minarovits, J}, title = {Anaerobic bacterial communities associated with oral carcinoma: Intratumoral, surface-biofilm and salivary microbiota.}, journal = {Anaerobe}, volume = {68}, number = {}, pages = {102300}, doi = {10.1016/j.anaerobe.2020.102300}, pmid = {33246097}, issn = {1095-8274}, mesh = {Anaerobiosis ; Animals ; Bacteria, Anaerobic/classification/genetics/*isolation & purification/*physiology ; Biofilms ; Humans ; *Microbiota ; Mouth Neoplasms/*microbiology ; Saliva/*microbiology ; }, abstract = {It was estimated that more than 700 bacterial species inhabit the oral cavity of healthy humans. Anaerobes comprise a significant fraction of the oral bacteriome and play an important role in the formation of multi-species biofilms attached to various anatomical sites. Bacterial biofilms are also associated with pathologic laesions of the oral cavity, including oral squamous cell carcinoma (OSCC), and distinct oral taxa could also be detected within the tumors, i.e. in deep biopsy samples. These observations suggested that certain oral bacteria or oral bacterial communities may play a causative role in oral carcinogenesis, in addition to the well characterized risk factors of oral cancer. Alternatively, it was also proposed that a subset of oral bacteria may have a growth advantage in the unique microenvironment of OSCC. Recently, a series of studies analysed the OSCC-associated bacterial communities using metataxonomic, metagenomic and metatranscriptomic approaches. This review outlines the major differences between the community structure of microbiota in tumor biopsy, surface-biofilm and salivary or oral wash samples collected from OSCC patients, compared to corresponding samples from control persons. A special emphasis is given to the anaerobic bacteria Fusobacterium nucleatum and Fusobacterium periodonticum that were characterised repeatedly as "OSCC-associated" in independent studies. Predicted microbial functions and relevant in vivo experimental models of oral carcinogenesis will also be summarized.}, } @article {pmid33246081, year = {2021}, author = {Motallebi, M and Alibolandi, Z and Aghmiyuni, ZF and van Leeuwen, WB and Sharif, MR and Moniri, R}, title = {Molecular analysis and the toxin, MSCRAMM, and biofilm genes of methicillin-resistant Staphylococcus aureus strains isolated from pemphigus wounds: A study based on SCCmec and dru typing.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {87}, number = {}, pages = {104644}, doi = {10.1016/j.meegid.2020.104644}, pmid = {33246081}, issn = {1567-7257}, mesh = {Adhesins, Bacterial/*genetics ; Anti-Bacterial Agents/*therapeutic use ; Bacterial Toxins/*genetics ; Biofilms/*drug effects ; Cross-Sectional Studies ; Genetic Variation ; Genotype ; Humans ; Iran/epidemiology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*genetics ; Pemphigus/drug therapy/*microbiology ; Virulence Factors/*genetics ; }, abstract = {INTRODUCTION: Pemphigus is a chronic autoimmune blistering disease. Pemphigus blisters can damage the natural skin barrier and increase the risk of life-threatening conditions. Colonization of pemphigus wounds with methicillin-resistant Staphylococcus aureus (MRSA) prolongs wound healing and increases mortality rate. Assessing MRSA prevalence, types, and toxin and adhesion genes can facilitate the detection of MRSA strains which cause infections, selection of appropriate treatments, and healing of pemphigus wounds. This study aimed to determine the SCCmec, the direct repeat unit (dru) types (dts), and the toxin, MSCRAMM, and biofilm genes of MRSA strains isolated from pemphigus wounds.

METHODS: In this cross-sectional study, 118 S. aureus isolates were gathered from 118 patients with pemphigus. MRSA detection was performed using the mecA gene. Using the polymerase chain reaction method, all MRSA isolates were assessed for the presence of the sea, seb, sec, tst, eta, pvl, hla, hlb, MSCRAMM, and ica genes. Typing and subtyping were performed through respectively SCCmec typing and dru typing methods. The Bionumerics software was used for analyzing the data and drawing the minimum spanning tree.

FINDINGS: From 118 S. aureus isolates, 51 were MRSA. SCCmec typing revealed the prevalence of SCCmec II with a prevalence of 64.7% (33 out of 51 isolates) and SCCmec III with a prevalence of 35.3% (18 out of 51 isolates). Dru typing indicated seven dts, namely dts 10a, 10g, 10m, 13i, 8h, 8i, and 9ca in two main clusters. The dt9ca was a new dru type and was registered in the dru-typing database (www.dru-typing.org). The prevalence rates of the hla, sea, and sec genes in MRSA isolates were respectively 54.9%, 27.4%, and 1.9%, while the hlb, seb, eta, and pvl genes were not detected at all. Only one MRSA with SCCmec III and dt10a carried the tst encoding gene. MSCRAMM gene analysis revealed the high prevalence of the eno (31.3%) and the fib (21.5%) genes. The prevalence rates of the icaA and icaD biofilm formation genes were 3.9% and 5.8%, respectively. There were no significant differences between the two detected SCCmec types and between the two detected dts clusters respecting the prevalence of the encoding genes of virulence factors and MSCRAMMs.

CONCLUSION: The toxin genes hla and sea are prevalent among MRSA strains with SCCmec II and III isolated from pemphigus wounds. The most prevalent dts are dt10a and dt10g among MRSA with SCCmec III and dt8h and dt8i among MRSA with SCCmec II.}, } @article {pmid33244058, year = {2020}, author = {Donkadokula, NY and Naz, I and Kola, AK and Saroj, D}, title = {Assessment of the aerobic glass beads fixed biofilm reactor (GBs-FBR) for the treatment of simulated methylene blue wastewater.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {20705}, pmid = {33244058}, issn = {2045-2322}, abstract = {The present research is focused on the application of glass beads (GBs) in fixed biofilm reactor (FBR) for the treatment of simulated methylene blue (MB) wastewater for 9 weeks under aerobic conditions. The COD of MB wastewater showed a reduction of 86.48% from 2000 to 270.4 mg/L, and BOD was declined up to 97.7% from 1095.5 to 25.03 mg/L. A drastic increase in the pH was observed until the 3rd week (8.5 to 8.28), and later, marginal changes between 8.30 ± 0.02 were noticed. A dramatic fluctuation was observed in ammonia concentration which increased (74.25 mg/L) up till the 2nd week, and from the 3rd week it started declining. In the 9th week, the ammonia concentration dropped to 16.5 mg/L. The color intensity increased significantly up till the 2nd week (259,237.46 Pt/Co) of the experiment and started decreasing slowly thereafter. The SEM-EDX analysis has shown the maximum quantity of carbon content in the GBs without biofilm, and then in the GB samples of 1st, and 9th-week old aerobic biofilms. Furthermore, Raman spectroscopy results revealed that the 9th-week GBs has a fine and strong MB peak and matched with that of the MB stock solution. Overall, the results have shown that the GBs filter media were suitable for the development of active biofilm communities for the treatment of dye wastewater. Thus, GBs-FBR system can be used for wastewater treatment to solve the current problem of industrial pollution in many countries and to protect the aquatic environment from dye pollution caused by the textile industry.}, } @article {pmid33243655, year = {2021}, author = {Tarafdar, A and Lee, JU and Jeong, JE and Lee, H and Jung, Y and Oh, HB and Woo, HY and Kwon, JH}, title = {Biofilm development of Bacillus siamensis ATKU1 on pristine short chain low-density polyethylene: A case study on microbe-microplastics interaction.}, journal = {Journal of hazardous materials}, volume = {409}, number = {}, pages = {124516}, doi = {10.1016/j.jhazmat.2020.124516}, pmid = {33243655}, issn = {1873-3336}, mesh = {Bacillus ; Biofilms ; Microplastics ; *Plastics ; *Polyethylene ; }, abstract = {A low-density polyethylene (LDPE) degrading bacterial strain (ATKU1) was isolated (99.86% similar with Bacillus siamensis KCTC 13613[T]) from a plastic dumping site to study interactions between microplastics (< 5 mm) and microorganisms. The strain was found (by scanning electron microscopy) to form biofilm on the microplastic surface after its interaction with LDPE (avg. Mw~4,000 Da and avg. Mn~1,700 Da) as a sole carbon source. Atomic force microscopy (AFM) showed the biofilm's 3-D developmental patterns and significantly increased Young's modulus of the LDPE surface after microbial treatment. Most of the viable bacteria attached to biofilms rather than media, which suggested their ability to utilize LDPE. Absorption bands of carbonyl, alkenyl, acyl, ester, primary-secondary alcohol, alkene groups and nitric oxides were found on the treated LDPE particles using Fourier-transform infrared spectroscopy. Fourier transform-ion cyclotron resonance mass spectrometry of the media indicated compositional shifts of the compounds after treatment (i.e., increase in the degree of unsaturation and increment in oxygen-to-carbon ratio) and presence of unsaturated hydrocarbons, polyketides, terpenoids, aliphatic/peptides, dicarboxylic acids, lipid-like compounds were hinted. The plastic degrading abilities of Bacillus siamensis ATKU1 suggest its probable application for large scale plastic bioremediation facility.}, } @article {pmid33242673, year = {2021}, author = {Feng, W and Yang, J and Ma, Y and Xi, Z and Ren, Q and Wang, S and Ning, H}, title = {Aspirin and verapamil increase the sensitivity of Candida albicans to caspofungin under planktonic and biofilm conditions.}, journal = {Journal of global antimicrobial resistance}, volume = {24}, number = {}, pages = {32-39}, doi = {10.1016/j.jgar.2020.11.013}, pmid = {33242673}, issn = {2213-7173}, mesh = {Aspirin/*pharmacology ; Biofilms ; *Candida albicans/drug effects ; Caspofungin/*pharmacology ; Microbial Sensitivity Tests ; Verapamil/*pharmacology ; }, abstract = {OBJECTIVES: This study aimed to investigate the effects of caspofungin (CAS) combined with aspirin (ASP) or verapamil (VPL) on the sensitivity of Candida albicans under planktonic and biofilm conditions.

METHODS: A total of 39 C. albicans clinical strains were used to construct biofilms. Sensitivity to ASP or VPL combined with CAS was analysed by broth microdilution. MIC50 values were obtained and the fractional inhibitory concentration index (FICI) was calculated. Subsequently, C. albicans ZY22 was selected for time-growth curve analysis and strains ZY15 and ZY22 were used for time-kill curve analysis.

RESULTS: Under planktonic condition the MIC50 of CAS was 0.0313-8 μg/mL following treatment with CAS alone, whereas it decreased to 0.0313-4 μg/mL following CAS combined with ASP or VPL. Under biofilm condition the MIC50 of CAS was 0.125-16 μg/mL following treatment with CAS alone, whereas it decreased to 0.0625-16 μg/mL or 0.0625-8 μg/mL following CAS combined with ASP or VPL. FICI results showed synergistic interactions between CAS and ASP under planktonic and biofilm conditions in 17 and 16 strains, respectively. However, synergistic interactions between CAS and VPL under planktonic and biofilm conditions were observed in 19 and 23 strains, respectively. Additionally, 8000 μg/mL ASP or 8 μg/mL VPL combined with CAS had better inhibitory effects on C. albicans.

CONCLUSION: ASP and VPL may be a sensitiser for CAS, and the antifungal effects of CAS may be sensitised by 8000 μg/mL ASP or 8 μg/mL VPL against C. albicans under planktonic and biofilm conditions.}, } @article {pmid33242145, year = {2020}, author = {Tsukatani, T and Sakata, F and Kuroda, R}, title = {A rapid and simple measurement method for biofilm formation inhibitory activity using 96-pin microtiter plate lids.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {12}, pages = {189}, doi = {10.1007/s11274-020-02964-6}, pmid = {33242145}, issn = {1573-0972}, mesh = {Bacteria/*drug effects/*growth & development ; Biofilms/*growth & development ; Culture Media ; Food Additives/*pharmacology ; Microbial Sensitivity Tests/*methods ; Staining and Labeling/methods ; Streptococcus mutans/drug effects/growth & development ; }, abstract = {The purpose of this study was to develop a rapid and simple measurement method for biofilm formation inhibitory activity, and to screen food additives and foodstuffs that inhibit biofilm formation. The measurement method for biofilm formation inhibitory activity was developed by combining biofilm formation on pins of microtiter plate lids and staining using crystal violet. The optimum conditions for biofilm formation on the pins were established for seven Gram-positive and six Gram-negative bacteria by investigations of media, incubation time, and pin materials. Minimum concentrations of food additives required to inhibit biofilm formation were determined using the proposed method. The values obtained by the proposed and conventional methods agreed well. In addition, by sequential measurements of minimum inhibitory concentrations and minimum bactericidal concentrations using the proposed method, mechanisms of inhibition of biofilm formation were assessed. Furthermore, inhibitory activities of the water extracts of 498 different plant foodstuffs on biofilm formation by Streptococcus mutans were measured; five of the extracts showed potent inhibitory activities. The method proposed here circumvents the tedious and time-consuming conventional method in which biofilms are cultivated on the bottom of wells of microtiter plates.}, } @article {pmid33241979, year = {2020}, author = {Doroudian, M and O'Neill, A and O'Reilly, C and Tynan, A and Mawhinney, L and McElroy, A and Webster, SS and MacLoughlin, R and Volkov, Y and E Armstrong, M and A O'Toole, G and Prina-Mello, A and C Donnelly, S}, title = {Aerosolized drug-loaded nanoparticles targeting migration inhibitory factors inhibit Pseudomonas aeruginosa-induced inflammation and biofilm formation.}, journal = {Nanomedicine (London, England)}, volume = {15}, number = {30}, pages = {2933-2953}, pmid = {33241979}, issn = {1748-6963}, support = {R01 AI083256/AI/NIAID NIH HHS/United States ; R37 AI083256/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; Humans ; Inflammation/drug therapy ; *Macrophage Migration-Inhibitory Factors ; *Nanoparticles ; *Pharmaceutical Preparations ; *Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa ; }, abstract = {Aim: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine, which has been shown to promote disease severity in cystic fibrosis. Methods: In this study, aerosolized drug-loaded nanoparticles containing SCD-19, an inhibitor of MIF's tautomerase enzymatic activity, were developed and characterized. Results: The aerosolized nanoparticles had an optimal droplet size distribution for deep lung deposition, with a high degree of biocompatibility and significant cellular uptake. Conclusion: For the first time, we have developed an aerosolized nano-formulation against MIF's enzymatic activity that achieved a significant reduction in the inflammatory response of macrophages, and inhibited Pseudomonas aeruginosa biofilm formation on airway epithelial cells. This represents a potential novel adjunctive therapy for the treatment of P. aeruginosa infection in cystic fibrosis.}, } @article {pmid33240995, year = {2020}, author = {Zhang, L and Li, J and Liang, J and Zhang, Z and Wei, Q and Wang, K}, title = {The effect of Cyclic-di-GMP on biofilm formation by Pseudomonas aeruginosa in a novel empyema model.}, journal = {Annals of translational medicine}, volume = {8}, number = {18}, pages = {1146}, pmid = {33240995}, issn = {2305-5839}, abstract = {BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) is a common pathogenic bacterium which causes pleural empyema, and infection of P. aeruginosa is often associated with biofilm. The aim of this study was to establish a model of rabbit empyema infected by P. aeruginosa to determine whether it causes the formation of biofilm in the pleural cavity. Furthermore, we investigated the effect of cyclic diguanosine monophosphate (c-di-GMP) on biofilm formation in this P. aeruginosa empyema model.

METHODS: Twenty rabbits were used and randomly divided into five groups: PAO1, PAO1ΔwspF, and PAO1/p lac-yhjH infection groups, and Luria-Bertani (LB) broth and turpentine control groups. A drainage catheter was implanted into the pleural cavity through thoracentesis. The three infection groups were respectively infected with PAO1, PAO1ΔwspF, and PAO1/p lac-yhjH strains, which caused empyema. The two control groups were injected with LB or turpentine. After 4 days of infection, we sacrificed the rabbits. We evaluated the pathology of pleura through hematoxylin-eosin staining. Colony count and crystal violet assay were used to analyze the biofilm formation on the surface of catheters. Scanning electron was used to observe the biofilm on the surface of the pleura. Peptide nucleic acids-fluorescence in situ hybridization (PNA-FISH) was used to observe the biofilm in the fibrinous deposition.

RESULTS: By the PNA-FISH assay, biofilms were observed in the fibrinous deposition of the three infection groups. The red fluorescence area of the PAO1ΔwspF infection group was larger than that of the PAO1 and PAO1/p lac -yhjH infection groups. Through electron microscopy, we observed that PAO1 strains were embedded in an electron-dense extracellular matrix on the surface of pleural tissue, and appeared to be biofilm-like structures. For the crystal violet assay, the optical density values of different groups were significantly different: PAO1ΔwspF > PAO1 > PAO1/p lac-yhjH > control groups (P<0.05).

CONCLUSIONS: To the best knowledge of the authors, this is the first study to report P. aeruginosa forming biofilm in a novel animal model of pleural empyema. In addition, c-di-GMP signaling molecules played an important role in biofilm formation in the pleural cavity.}, } @article {pmid33240905, year = {2020}, author = {Baldan, R and Sendi, P}, title = {Precision Medicine in the Diagnosis and Management of Orthopedic Biofilm Infections.}, journal = {Frontiers in medicine}, volume = {7}, number = {}, pages = {580671}, pmid = {33240905}, issn = {2296-858X}, abstract = {Orthopedic biofilm infections are difficult to treat and require a multidisciplinary approach to diagnostics and management. Recent advances in the field include methods to disrupt biofilm, sequencing tools, and antibiotic susceptibility tests for bacteria residing in biofilm. The observation of interclonal differences in biofilm properties of the causative microorganisms, together with considerations of comorbidities and polypharmacy in a growing aging population, calls for a personalized approach to treat these infections. In this article, we highlight aspects of precision medicine that may open new perspectives in the diagnosis and management of orthopedic biofilm infections.}, } @article {pmid33240599, year = {2020}, author = {Juntarachot, N and Sirilun, S and Kantachote, D and Sittiprapaporn, P and Tongpong, P and Peerajan, S and Chaiyasut, C}, title = {Anti-Streptococcus mutans and anti-biofilm activities of dextranase and its encapsulation in alginate beads for application in toothpaste.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e10165}, pmid = {33240599}, issn = {2167-8359}, abstract = {BACKGROUND: The accumulation of plaque causes oral diseases. Dental plaque is formed on teeth surfaces by oral bacterial pathogens, particularly Streptococcus mutans, in the oral cavity. Dextranase is one of the enzymes involved in antiplaque accumulation as it can prevent dental caries by the degradation of dextran, which is a component of plaque biofilm. This led to the idea of creating toothpaste containing dextranase for preventing oral diseases. However, the dextranase enzyme must be stable in the product; therefore, encapsulation is an attractive way to increase the stability of this enzyme.

METHODS: The activity of food-grade fungal dextranase was measured on the basis of increasing ratio of reducing sugar concentration, determined by the reaction with 3, 5-dinitrosalicylic acid reagent. The efficiency of the dextranase enzyme was investigated based on its minimal inhibitory concentration (MIC) against biofilm formation by S. mutans ATCC 25175. Box-Behnken design (BBD) was used to study the three factors affecting encapsulation: pH, calcium chloride concentration, and sodium alginate concentration. Encapsulation efficiency (% EE) and the activity of dextranase enzyme trapped in alginate beads were determined. Then, the encapsulated dextranase in alginate beads was added to toothpaste base, and the stability of the enzyme was examined. Finally, sensory test and safety evaluation of toothpaste containing encapsulated dextranase were done.

RESULTS: The highest activity of the dextranase enzyme was 4401.71 unit/g at a pH of 6 and 37 °C. The dextranase at its MIC (4.5 unit/g) showed strong inhibition against the growth of S. mutans. This enzyme at 1/2 MIC also showed a remarkable decrease in biofilm formation by S. mutans. The most effective condition of dextranase encapsulation was at a pH of 7, 20% w/v calcium chloride and 0.85% w/v sodium alginate. Toothpaste containing encapsulated dextranase alginate beads produced under suitable condition was stable after 3 months of storage, while the sensory test of the product was accepted at level 3 (like slightly), and it was safe.

CONCLUSION: This research achieved an alternative health product for oral care by formulating toothpaste with dextranase encapsulated in effective alginate beads to act against cariogenic bacteria, like S. mutants, by preventing dental plaque.}, } @article {pmid33240514, year = {2020}, author = {Hemati, S and Kouhsari, E and Sadeghifard, N and Maleki, A and Omidi, N and Mahdavi, Z and Pakzad, I}, title = {Sub-minimum inhibitory concentrations of biocides induced biofilm formation in Pseudomonas aeruginosa.}, journal = {New microbes and new infections}, volume = {38}, number = {}, pages = {100794}, pmid = {33240514}, issn = {2052-2975}, abstract = {It is clear that biofilm formation causes many serious health-care problems. Interestingly, sub minimum inhibitory concentrations (sub-MICs) of some biocides can induce biofilm formation in bacteria. We investigated whether sub-MICs of Savlon, chlorhexidine and deconex®, as biocidal products, can induce biofilm formation in clinical isolates of Pseudomonas aeruginosa. To determine MICs and biofilm formation, we performed microtitre plate assays. All three biocides induced biofilm formation at sub-MICs; Savlon was the most successful antiseptic agent to induce biofilm formation among P. aeruginosa isolates. Deconex had the best inhibition effect on planktonic cultures of P. aeruginosa isolates. We concluded that sub-MICs of Savlon and deconex could significantly induce biofilm formation.}, } @article {pmid33240473, year = {2020}, author = {Nguyen, HTT and Nguyen, TH and Otto, M}, title = {The staphylococcal exopolysaccharide PIA - Biosynthesis and role in biofilm formation, colonization, and infection.}, journal = {Computational and structural biotechnology journal}, volume = {18}, number = {}, pages = {3324-3334}, pmid = {33240473}, issn = {2001-0370}, abstract = {Exopolysaccharide is a key part of the extracellular matrix that contributes to important mechanisms of bacterial pathogenicity, most notably biofilm formation and immune evasion. In the human pathogens Staphylococcus aureus and S. epidermidis, as well as in many other staphylococcal species, the only exopolysaccharide is polysaccharide intercellular adhesin (PIA), a cationic, partially deacetylated homopolymer of N-acetylglucosamine, whose biosynthetic machinery is encoded in the ica locus. PIA production is strongly dependent on environmental conditions and controlled by many regulatory systems. PIA contributes significantly to staphylococcal biofilm formation and immune evasion mechanisms, such as resistance to antimicrobial peptides and ingestion and killing by phagocytes, and presence of the ica genes is associated with infectivity. Due to its role in pathogenesis, PIA has raised considerable interest as a potential vaccine component or target.}, } @article {pmid33240251, year = {2020}, author = {Meyer, KJ and Taylor, HB and Seidel, J and Gates, MF and Lewis, K}, title = {Pulse Dosing of Antibiotic Enhances Killing of a Staphylococcus aureus Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {596227}, pmid = {33240251}, issn = {1664-302X}, abstract = {Biofilms are highly tolerant to antibiotics and underlie the recalcitrance of many chronic infections. We demonstrate that mature Staphylococcus aureus biofilms can be substantially sensitized to the treatment by pulse dosing of an antibiotic - in this case, oxacillin. Pulse (periodic) dosing was compared to continuous application of antibiotic and was studied in a novel in vitro flow system which allowed for robust biofilm growth and tractable pharmacokinetics of dosing regimens. Our results highlight that a subpopulation of the biofilm survives antibiotic without becoming resistant, a population we refer to as persister bacteria. When oxacillin was continuously present the persister level did not decline, but, importantly, providing correctly timed periodic breaks decreased the surviving population. We found that the length of the periodic break impacted efficacy, and there was an optimal length that sensitized the biofilm to repeat treatment without allowing resistance expansion. Periodic dosing provides a potential simple solution to a complicated problem.}, } @article {pmid33240007, year = {2020}, author = {Kwiatkowski, P and Grygorcewicz, B and Pruss, A and Wojciuk, B and Giedrys-Kalemba, S and Dołêgowska, B and Zielińska-Bliźniewska, H and Olszewski, J and Sienkiewicz, M and Kochan, E}, title = {Synergistic effect of fennel essential oil and hydrogen peroxide on bacterial biofilm.}, journal = {Postepy dermatologii i alergologii}, volume = {37}, number = {5}, pages = {690-694}, pmid = {33240007}, issn = {1642-395X}, abstract = {INTRODUCTION: Staphylococcal biofilm formation significantly challenges wound management. The causes of difficult-to-treat wounds are not only methicillin-resistant staphylococci, but also methicillin-sensitive strains with different patterns of resistance. Bacterial biofilm significantly limits the access and activity of antimicrobials used in dermatological infections.

AIM: To evaluate the synergistic effect of fennel essential oil (FEO) and H2O2 on biofilm formation by Staphylococcus aureus (MSSA and MRSA) reference strains.

MATERIAL AND METHODS: Minimum inhibitory concentration (MIC) values were determined for FEO and H2O2 against S. aureus reference strains by the broth microdilution method. The combined effects of the FEO and H2O2 were calculated and expressed in terms of a fractional inhibitory concentration index (FICI) using the checkerboard method. The FEO composition was analyzed by the GC-MS method. The data were analysed by one-way ANOVA.

RESULTS: Decreased MIC values for FEO combined with H2O2 were observed in comparison to FEO itself. The combinations of FEO and H2O2 determined synergistic effects on all S. aureus reference strains. Subinhibitory concentration of FEO alone and in combination with 0.5 MIC of H2O2 significantly decreased the production of biofilm biomass in S. aureus strains and reduced the metabolic activity of attached cells.

CONCLUSIONS: Combination of fennel essential oil containing nearly 80% trans-anethole and H2O2 represents a potential for further basic and applied research on wound management.}, } @article {pmid33239369, year = {2020}, author = {Cooke, AC and Florez, C and Dunshee, EB and Lieber, AD and Terry, ML and Light, CJ and Schertzer, JW}, title = {Pseudomonas Quinolone Signal-Induced Outer Membrane Vesicles Enhance Biofilm Dispersion in Pseudomonas aeruginosa.}, journal = {mSphere}, volume = {5}, number = {6}, pages = {}, pmid = {33239369}, issn = {2379-5042}, support = {R15 GM135862/GM/NIGMS NIH HHS/United States ; R21 AI121848/AI/NIAID NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Bacterial Outer Membrane Proteins/*metabolism ; Bacterial Proteins/metabolism ; *Biofilms ; Cell Membrane/metabolism ; Organelle Biogenesis ; Pseudomonas aeruginosa/*metabolism/pathogenicity ; Quinolones/*metabolism ; Quorum Sensing ; Virulence Factors/metabolism ; }, abstract = {Bacterial biofilms are major contributors to chronic infections in humans. Because they are recalcitrant to conventional therapy, they present a particularly difficult treatment challenge. Identifying factors involved in biofilm development can help uncover novel targets and guide the development of antibiofilm strategies. Pseudomonas aeruginosa causes surgical site, burn wound, and hospital-acquired infections and is also associated with aggressive biofilm formation in the lungs of cystic fibrosis patients. A potent but poorly understood contributor to P. aeruginosa virulence is the ability to produce outer membrane vesicles (OMVs). OMV trafficking has been associated with cell-cell communication, virulence factor delivery, and transfer of antibiotic resistance genes. Because OMVs have almost exclusively been studied using planktonic cultures, little is known about their biogenesis and function in biofilms. Several groups have shown that Pseudomonas quinolone signal (PQS) induces OMV formation in P. aeruginosa Our group described a biophysical mechanism for this and recently showed it is operative in biofilms. Here, we demonstrate that PQS-induced OMV production is highly dynamic during biofilm development. Interestingly, PQS and OMV synthesis are significantly elevated during dispersion compared to attachment and maturation stages. PQS biosynthetic and receptor mutant biofilms were significantly impaired in their ability to disperse, but this phenotype was rescued by genetic complementation or exogenous addition of PQS. Finally, we show that purified OMVs can actively degrade extracellular protein, lipid, and DNA. We therefore propose that enhanced production of PQS-induced OMVs during biofilm dispersion facilitates cell escape by coordinating the controlled degradation of biofilm matrix components.IMPORTANCE Treatments that manipulate biofilm dispersion hold the potential to convert chronic drug-tolerant biofilm infections from protected sessile communities into released populations that are orders-of-magnitude more susceptible to antimicrobial treatment. However, dispersed cells often exhibit increased acute virulence and dissemination phenotypes. A thorough understanding of the dispersion process is therefore critical before this promising strategy can be effectively employed. Pseudomonas quinolone signal (PQS) has been implicated in early biofilm development, but we hypothesized that its function as an outer membrane vesicle (OMV) inducer may contribute at multiple stages. Here, we demonstrate that PQS and OMVs are differentially produced during Pseudomonas aeruginosa biofilm development and provide evidence that effective biofilm dispersion is dependent on the production of PQS-induced OMVs, which likely act as delivery vehicles for matrix-degrading enzymes. These findings lay the groundwork for understanding OMV contributions to biofilm development and suggest a model to explain the controlled matrix degradation that accompanies biofilm dispersion in many species.}, } @article {pmid33238622, year = {2020}, author = {Tits, J and Cammue, BPA and Thevissen, K}, title = {Combination Therapy to Treat Fungal Biofilm-Based Infections.}, journal = {International journal of molecular sciences}, volume = {21}, number = {22}, pages = {}, pmid = {33238622}, issn = {1422-0067}, support = {IOFm/05/022//KU Leuven (to Karin Thevissen)/ ; }, mesh = {Antifungal Agents/*therapeutic use ; Biofilms/*drug effects ; Candida/drug effects/pathogenicity ; Drug Resistance, Fungal/*drug effects ; Humans ; Microbial Sensitivity Tests ; Mycoses/*drug therapy/genetics/microbiology ; }, abstract = {An increasing number of people is affected by fungal biofilm-based infections, which are resistant to the majority of currently-used antifungal drugs. Such infections are often caused by species from the genera Candida, Aspergillus or Cryptococcus. Only a few antifungal drugs, including echinocandins and liposomal formulations of amphotericin B, are available to treat such biofilm-based fungal infections. This review discusses combination therapy as a novel antibiofilm strategy. More specifically, in vitro methods to discover new antibiofilm combinations will be discussed. Furthermore, an overview of the main modes of action of promising antibiofilm combination treatments will be provided as this knowledge may facilitate the optimization of existing antibiofilm combinations or the development of new ones with a similar mode of action.}, } @article {pmid33238583, year = {2020}, author = {Elgamoudi, BA and Taha, T and Korolik, V}, title = {Inhibition of Campylobacter jejuni Biofilm Formation by D-Amino Acids.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33238583}, issn = {2079-6382}, abstract = {The ability of bacterial pathogens to form biofilms is an important virulence mechanism in relation to their pathogenesis and transmission. Biofilms play a crucial role in survival in unfavorable environmental conditions, acting as reservoirs of microbial contamination and antibiotic resistance. For intestinal pathogen Campylobacter jejuni, biofilms are considered to be a contributing factor in transmission through the food chain and currently, there are no known methods for intervention. Here, we present an unconventional approach to reducing biofilm formation by C. jejuni by the application of D-amino acids (DAs), and L-amino acids (LAs). We found that DAs and not LAs, except L-alanine, reduced biofilm formation by up to 70%. The treatment of C. jejuni cells with DAs changed the biofilm architecture and reduced the appearance of amyloid-like fibrils. In addition, a mixture of DAs enhanced antimicrobial efficacy of D-Cycloserine (DCS) up to 32% as compared with DCS treatment alone. Unexpectedly, D-alanine was able to reverse the inhibitory effect of other DAs as well as that of DCS. Furthermore, L-alanine and D-tryptophan decreased transcript levels of peptidoglycan biosynthesis enzymes alanine racemase (alr) and D-alanine-D-alanine ligase (ddlA) while D-serine was only able to decrease the transcript levels of alr. Our findings suggest that a combination of DAs could reduce biofilm formation, viability and persistence of C. jejuni through dysregulation of alr and ddlA.}, } @article {pmid33237146, year = {2020}, author = {Sette-DE-Souza, PH and Santana, CP and Sousa, IMO and Foglio, MA and Medeiros, FD and Medeiros, ACD}, title = {Schinopsis brasiliensis Engl. to combat the biofilm-dependents diseases in vitro.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {92}, number = {4}, pages = {e20200408}, doi = {10.1590/0001-3765202020200408}, pmid = {33237146}, issn = {1678-2690}, mesh = {*Anacardiaceae ; Biofilms ; *Dental Caries ; Humans ; Microbial Sensitivity Tests ; Phytochemicals ; Plant Extracts/pharmacology ; }, abstract = {Dental caries and periodontal disease are the most prevalent of the biofilm-dependent diseases. With numerous side effects on the use of chlorhexidine, the search for new safe therapeutic alternatives for microorganisms involved with these diseases increases every day. This study aimed to evaluate the antimicrobial activity and cytotoxicity of extracts made from the bark of Schinopsis brasiliensis Engl. against five oral microorganisms and analyze their phytochemical and thermal degradation profile. The liquid-liquid partition was performed with hexane, chloroform and ethyl acetate. The identification and quantification of the chemical marker was done. Antimicrobial activity was evaluated based on the minimum inhibitory concentration. The cytotoxicity was analyzed based on the hemolysing potential of the samples. The thermal degradation profile was performed by two different methods. Gallic acid was identified as the main compound of the samples and showed the highest amount in the chloroform fraction. All samples were able to inhibit the growth of the microorganisms tested and showed no cytotoxicity. The ethanol extract absorbs less heat than the fractions. All samples exhibited exothermic peak consistent with degradation of gallic acid. Based on the results, the samples used are potential candidates for use in dental formulations for biofilm control.}, } @article {pmid33236843, year = {2021}, author = {Kataoka, Y and Kunimitsu, M and Nakagami, G and Koudounas, S and Weller, CD and Sanada, H}, title = {Effectiveness of ultrasonic debridement on reduction of bacteria and biofilm in patients with chronic wounds: A scoping review.}, journal = {International wound journal}, volume = {18}, number = {2}, pages = {176-186}, pmid = {33236843}, issn = {1742-481X}, support = {20H04010//JSPS KAKENHI/ ; }, mesh = {Bacteria ; *Biofilms ; Debridement/*methods ; Humans ; *Ultrasonics ; }, abstract = {Chronic wounds are defined as "hard-to-heal" wounds that are caused by disordered mechanisms of wound healing. Chronic wounds have a high risk of infection and can form biofilms, leading to the release of planktonic bacteria, which causes persistent infections locally or remotely. Therefore, infection control and removal of the biofilm in chronic wounds are essential. Recently, ultrasonic debridement was introduced as a new method to reduce infection and promote the healing of chronic wounds. This scoping review aimed to evaluate the effectiveness of ultrasonic debridement on the changes in bacteria and biofilms, and consequently the wound healing rate of chronic wounds. A total of 1021 articles were identified through the database search, and nine papers were eligible for inclusion. Findings suggest that non-contact devices are useful for wound healing as they reduce the inflammatory response, although the bacterial load is not significantly changed. Ultrasonic debridement devices that require direct contact with the wound promote wound healing through reduction of biofilm or bacterial load. The optimum settings for ultrasonic debridement using a non-contact device are relatively consistent, but the settings for devices that require direct contact are diverse. Further studies on ultrasonic debridement in chronic wounds are required.}, } @article {pmid33235984, year = {2020}, author = {Quinn, J and McFadden, R and Chan, CW and Carson, L}, title = {Titanium for Orthopedic Applications: An Overview of Surface Modification to Improve Biocompatibility and Prevent Bacterial Biofilm Formation.}, journal = {iScience}, volume = {23}, number = {11}, pages = {101745}, pmid = {33235984}, issn = {2589-0042}, abstract = {Titanium and its alloys have emerged as excellent candidates for use as orthopedic biomaterials. Nevertheless, there are often complications arising after implantation of orthopedic devices, most notably prosthetic joint infection and aseptic loosening. To ensure that implanted devices remain functional in situ, innovation in surface modification has attracted much attention in the effort to develop orthopedic materials with optimal characteristics at the biomaterial-tissue interface. This review will draw together metallurgy, surface engineering, biofilm microbiology, and biomaterial science. It will serve to appreciate why titanium and its alloys are frequently used orthopedic biomaterials and address some of the challenges facing these biomaterials currently, including the significant problem of device-associated infection. Finally, the authors shall consolidate and evaluate surface modification techniques employed to overcome some of these issues by offering a unique perspective as to the direction in which research is headed from a broad, interdisciplinary point of view.}, } @article {pmid33235708, year = {2020}, author = {Mirani, ZA and Urooj, S and Khan, MN and Khan, AB and Shaikh, IA and Siddiqui, A}, title = {An effective weapon against biofilm consortia and small colony variants of MRSA.}, journal = {Iranian journal of basic medical sciences}, volume = {23}, number = {11}, pages = {1494-1498}, pmid = {33235708}, issn = {2008-3866}, abstract = {OBJECTIVES: This study was designed to investigate the effect of AgNPs (10 nm and 30 nm) on different phenotypes of Staphylococcus aureus biofilm consortia.

MATERIALS AND METHODS: A total of eighteen biofilm-producing isolates of Methicillin-Resistant S. aureus (MRSA) were used in the present study. Tube methods, Congo-red agar method, and scanning electron microscopy (SEM) were used to study biofilm phenotypes. Population analysis assay on a tryptone soya agar (TSA) plate was applied to study the different phenotypes of biofilm consortia. The effect of AgNPs was evaluated by broth dilution assay.

RESULTS: Results showed that biofilm consortia harbour different phenotypes, i.e., planktonic, metabolically inactive cells, and small colony variants (SCVs) or persister cells. The focus of the present study is the effect of AgNPs on biofilm consortia of MRSA, particularly on the SCVs population. Large size AgNPs (30 nm) were unable to diffuse through extracellular matrix material coverings of the biofilm consortia; they were only active against the planktonic population that occupies the outer surface of consortia. The smaller AgNPs (10 nm), on the other hand, were found to diffuse through the matrix material and hence were effective against planktonic as well as metabolically inactive population of consortia. Moreover, 30 nm AgNPs take 6 hr to disperse off and kill planktonic and upper surface indwellers. The 10 nm AgNPs disperse and kill the majority of biofilm indwellers within 20 min.

CONCLUSION: The present study showed that 10 nm AgNPs can easily penetrate inside the biofilm and are active against all of the indwellers of consortia.}, } @article {pmid33234179, year = {2021}, author = {Burgos-Garay, M and Ganim, C and de Man, TJB and Davy, T and Mathers, AJ and Kotay, S and Daniels, J and Perry, KA and Breaker, E and Donlan, RM}, title = {Colonization of carbapenem-resistant Klebsiella pneumoniae in a sink-drain model biofilm system.}, journal = {Infection control and hospital epidemiology}, volume = {42}, number = {6}, pages = {722-730}, doi = {10.1017/ice.2020.1287}, pmid = {33234179}, issn = {1559-6834}, mesh = {Biofilms ; *Carbapenem-Resistant Enterobacteriaceae ; Carbapenems/pharmacology ; Humans ; *Klebsiella pneumoniae/genetics ; RNA, Ribosomal, 16S ; }, abstract = {BACKGROUND: Sink drains in healthcare facilities may provide an environment for antimicrobial-resistant microorganisms, including carbapenemase-producing Klebsiella pneumoniae (CPKP).

METHODS: We investigated the colonization of a biofilm consortia by CPKP in a model system simulating a sink-drain P-trap. Centers for Disease Control (CDC) biofilm reactors (CBRs) were inoculated with microbial consortia originally recovered from 2 P-traps collected from separate patient rooms (designated rooms A and B) in a hospital. Biofilms were grown on stainless steel (SS) or polyvinyl chloride (PVC) coupons in autoclaved municipal drinking water (ATW) for 7 or 28 days.

RESULTS: Microbial communities in model systems (designated CBR-A or CBR-B) were less diverse than communities in respective P-traps A and B, and they were primarily composed of β and γ Proteobacteria, as determined using 16S rRNA community analysis. Following biofilm development CBRs were inoculated with either K. pneumoniae ST45 (ie, strain CAV1016) or K. pneumoniae ST258 KPC+ (ie, strain 258), and samples were collected over 21 days. Under most conditions tested (CBR-A: SS, 7-day biofilm; CBR-A: PVC, 28-day biofilm; CBR-B: SS, 7-day and 28-day biofilm; CBR-B: PVC, 28-day biofilm) significantly higher numbers of CAV1016 were observed compared to 258. CAV1016 showed no significant difference in quantity or persistence based on biofilm age (7 days vs 28 days) or substratum type (SS vs PVC). However, counts of 258 were significantly higher on 28-day biofilms and on SS.

CONCLUSIONS: These results suggest that CPKP persistence in P-trap biofilms may be strain specific or may be related to the type of P-trap material or age of the biofilm.}, } @article {pmid33233878, year = {2020}, author = {Ng, G and Li, M and Yeow, J and Jung, K and Pester, CW and Boyer, C}, title = {Benchtop Preparation of Polymer Brushes by SI-PET-RAFT: The Effect of the Polymer Composition and Structure on Inhibition of a Pseudomonas Biofilm.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {49}, pages = {55243-55254}, doi = {10.1021/acsami.0c15221}, pmid = {33233878}, issn = {1944-8252}, mesh = {Biofilms/drug effects/*growth & development ; Biofouling/prevention & control ; Catalysis ; Glass/chemistry ; Light ; Nitrogen Oxides/chemistry ; Oxidation-Reduction ; Polymerization ; Polymers/chemical synthesis/*chemistry/pharmacology ; Pseudomonas/*physiology ; Surface Properties ; }, abstract = {We report a high-throughput method for producing surface-tethered polymeric brushes on glass substrates via surface-initiated photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT). Due to its excellent oxygen tolerance, SI-PET-RAFT allows brush growth using low reagent volumes (30 μL) without prior degassing. An initial 28 homopolymer brush library was successfully prepared and screened with respect to their antifouling performance. The high-throughput approach was further exploited to expand the library to encompass statistical, gradient, and block architectures to investigate the effect of monomer composition and distribution using two monomers of disparate performance. In this manner, the degree of attachment from Gram-negative Pseudomonas aeruginosa (PA) bacterial biofilms could be tuned between the bounds set by the homopolymer brushes.}, } @article {pmid33233591, year = {2020}, author = {Osland, AM and Vestby, LK and Nesse, LL}, title = {The Effect of Disinfectants on Quinolone Resistant E. coli (QREC) in Biofilm.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33233591}, issn = {2076-2607}, support = {250212//Norges Forskningsråd/ ; }, abstract = {The aim of disinfection is to reduce the number of microorganisms on surfaces which is a challenge due to biofilms. In the present study, six quinolone resistant Escherichia coli (QREC) strains with three different biofilm matrix compositions were included to assess the log10 colony forming units (CFU) reduction effect of three disinfectants at various exposure times on biofilm of different ages and morphotypes. Biofilm was formed on stainless steel coupons for two and five days before transferred to tubes with Virocid 0, 25%, VirkonS 1%, and TP990 1% and left for various exposure times. The biofilms were scraped off and serial dilutions were spread on blood agar plates where colony forming units (CFU) were counted. A mean log10 CFU reduction ≥4 was seen on two-day-old biofilm with VirkonS and Virocid (30 min) but not on five-day old biofilm. TP990 did not display sufficient effect under the conditions tested. The bactericidal effect was inferior to that reported on planktonic bacteria. The findings of this study should be considered when establishing both disinfectant routines and standard susceptibility tests, which further should accommodate E. coli biofilms and not only Pseudomonas as is the case today.}, } @article {pmid33233348, year = {2020}, author = {Gilbert-Girard, S and Savijoki, K and Yli-Kauhaluoma, J and Fallarero, A}, title = {Screening of FDA-Approved Drugs Using a 384-Well Plate-Based Biofilm Platform: The Case of Fingolimod.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33233348}, issn = {2076-2607}, support = {722467//H2020 Marie Skłodowska-Curie Actions/ ; }, abstract = {In an effort to find new repurposed antibacterial compounds, we performed the screening of an FDA-approved compounds library against Staphylococcus aureus American Type Culture Collection (ATCC) 25923. Compounds were evaluated for their capacity to prevent both planktonic growth and biofilm formation as well as to disrupt pre-formed biofilms. One of the identified initial hits was fingolimod (FTY720), an immunomodulator approved for the treatment of multiple sclerosis, which was then selected for follow-up studies. Fingolimod displayed a potent activity against S. aureus and S. epidermidis with a minimum inhibitory concentration (MIC) within the range of 12-15 µM at which concentration killing of all the bacteria was confirmed. A time-kill kinetic study revealed that fingolimod started to drastically reduce the viable bacterial count within two hours and we showed that no resistance developed against this compound for up to 20 days. Fingolimod also displayed a high activity against Acinetobacter baumannii (MIC 25 µM) as well as a modest activity against Escherichia coli and Pseudomonas aeruginosa. In addition, fingolimod inhibited quorum sensing in Chromobacterium violaceum and might therefore target this signaling pathway in certain Gram-negative bacteria. In conclusion, we present the identification of fingolimod from a compound library and its evaluation as a potential repurposed antibacterial compound.}, } @article {pmid33233331, year = {2020}, author = {Falghoush, A and Beyenal, H and Call, DR}, title = {Sequential Hypertonic-Hypotonic Treatment Enhances Efficacy of Antibiotic against Acinetobacter baumannii Biofilm Communities.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33233331}, issn = {2079-6382}, abstract = {Infections with bacterial biofilm communities are highly tolerant of antibiotics. This protection is attributed, in part, to a hydrated extracellular polymeric substance (EPS) that surrounds the bacterial community and that limits antibiotic diffusion. In this study, we evaluated whether it is possible to dehydrate and then re-hydrate a biofilm as a means to increase antibiotic penetration and efficacy. Acinetobacter baumannii biofilms (24 h) were exposed to hypertonic concentrations of maltodextrin, sucrose or polyethylene glycol (PEG) as the dehydration step. These biofilms were then washed with deionized water containing 10 times the concentration of antibiotics needed to kill these bacteria in broth culture (50 µg/mL tobramycin, 300 µg/mL chloramphenicol, 20 µg/mL ciprofloxacin or 100 µg/mL erythromycin) as the rehydration step. Biofilms were then harvested, and the number of viable cells was determined. Sequential treatment with PEG and tobramycin reduced cell counts 4 to 7 log (p < 0.05) relative to combining PEG and tobramycin in a single treatment, and 3 to 7 log relative to tobramycin treatment alone (p < 0.05). Results were variable for other osmotic compounds and antibiotics depending on the concentrations used, likely related to mass and hydrophobicity. Our findings support future clinical evaluation of sequential regimens of hypertonic and hypotonic solutions to enhance antibiotic efficacy against chronic biofilm infections.}, } @article {pmid33233307, year = {2020}, author = {Li, J and Zhao, X}, title = {Effects of quorum sensing on the biofilm formation and viable but non-culturable state.}, journal = {Food research international (Ottawa, Ont.)}, volume = {137}, number = {}, pages = {109742}, doi = {10.1016/j.foodres.2020.109742}, pmid = {33233307}, issn = {1873-7145}, mesh = {Bacteria ; *Biofilms ; Humans ; *Quorum Sensing ; Virulence Factors ; }, abstract = {Quorum sensing exists widely in all kinds of microorganisms and is a communication channel for microorganisms. Many bacterial processes, including virulence factor expression, biofilm formation, and viable but non-culturable (VBNC) cell resuscitation, are mediated by quorum sensing, and biofilm formation complicates the treatment of various infections. Foodborne pathogens can enter VBNC state in extreme environments, and pathogens in VBNC state can evade traditional detection and resuscitate under appropriate conditions, causing potential harm to human health. The disruption of quorum sensing may decisively help control biofilm formation and VBNC cell resuscitation. This review describes the quorum sensing systems of various bacteria and major fungi, and summarizes the role of bacterial quorum sensing system in biofilm formation and VBNC resuscitation. In addition, the relationship between quorum sensing inhibitors (QSI) with biofilms and VBNC is also discussed.}, } @article {pmid33233106, year = {2020}, author = {Lianou, A and Nychas, GE and Koutsoumanis, KP}, title = {Strain variability in biofilm formation: A food safety and quality perspective.}, journal = {Food research international (Ottawa, Ont.)}, volume = {137}, number = {}, pages = {109424}, doi = {10.1016/j.foodres.2020.109424}, pmid = {33233106}, issn = {1873-7145}, mesh = {*Biofilms ; *Food Microbiology ; Food Safety ; }, abstract = {The inherent differences in microbial behavior among identically treated strains of the same microbial species, referred to as "strain variability", are regarded as an important source of variability in microbiological studies. Biofilms are defined as the structured multicellular communities with complex architecture that enable microorganisms to grow adhered to abiotic or living surfaces and constitute a fundamental aspect of microbial ecology. The research studies assessing the strain variability in biofilm formation are relatively few compared to the ones evaluating other aspects of microbial behavior such as virulence, growth and stress resistance. Among the available research data on intra-species variability in biofilm formation, compiled and discussed in the present review, most of them refer to foodborne pathogens as compared to spoilage microorganisms. Molecular and physiological aspects of biofilm formation potentially related to strain-specific responses, as well as information on the characterization and quantitative description of this type of biological variability are presented and discussed. Despite the considerable amount of available information on the strain variability in biofilm formation, there are certain data gaps and still-existing challenges that future research should cover and address. Current and future advances in systems biology and omics technologies are expected to aid significantly in the explanation of phenotypic strain variability, including biofilm formation variability, allowing for its integration in microbiological risk assessment.}, } @article {pmid33233092, year = {2020}, author = {Fan, Y and Qiao, J and Lu, Z and Fen, Z and Tao, Y and Lv, F and Zhao, H and Zhang, C and Bie, X}, title = {Influence of different factors on biofilm formation of Listeria monocytogenes and the regulation of cheY gene.}, journal = {Food research international (Ottawa, Ont.)}, volume = {137}, number = {}, pages = {109405}, doi = {10.1016/j.foodres.2020.109405}, pmid = {33233092}, issn = {1873-7145}, mesh = {Biofilms ; Flagella ; Food Handling ; Hydrophobic and Hydrophilic Interactions ; *Listeria monocytogenes/genetics ; }, abstract = {In a food-processing environment, bacterial cells often adhere to surfaces and form biofilms to protect themselves from external adverse influences. Our study aimed to identify the influence of environmental factors and cell properties on Listeria monocytogenes biofilm formation. Biofilm formation was quantified through measuring the optical density at 590 nm (OD590 nm) after crystal violet staining. Neutral pH and 37oC were beneficial for biofilm formation whereas the influence of glucose (0.0-1.0%) and sodium chloride (0.0-1.0%) were strain-dependent. In general, the addition of sodium chloride and glucose increased biofilm formation in most strains compared to that in controls with no sodium chloride or glucose added. Bacteria with strong biofilm-forming capacity always produced large amounts of biofilm in most instances. Biofilm formation positively correlated with the cell surface hydrophobicity and motility but was independent from planktonic cell growth. The expression of flagella-related flaA, motB, and the two-component chemotactic system cheA/Y genes in biofilm cells increased compared to that in planktonic cells. Meanwhile, a cheY knockout mutant was constructed, and decreased biofilm-formation ability along with reduced cell-surface hydrophobicity were found in the non-motile mutant. Furthermore, the cheY knockout mutant showed no change in growth, and pH susceptibility compared to that in the wild-type strain.}, } @article {pmid33231899, year = {2021}, author = {Mawla, GD and Hall, BM and Cárcamo-Oyarce, G and Grant, RA and Zhang, JJ and Kardon, JR and Ribbeck, K and Sauer, RT and Baker, TA}, title = {ClpP1P2 peptidase activity promotes biofilm formation in Pseudomonas aeruginosa.}, journal = {Molecular microbiology}, volume = {115}, number = {6}, pages = {1094-1109}, pmid = {33231899}, issn = {1365-2958}, support = {R01 GM101988/GM/NIGMS NIH HHS/United States ; T32 GM007287/GM/NIGMS NIH HHS/United States ; S10 OD021527/OD/NIH HHS/United States ; P30 GM124165/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; R01 EB017755/EB/NIBIB NIH HHS/United States ; R01 AI016892/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Binding Sites ; Biofilms/growth & development ; Crystallography, X-Ray ; Endopeptidase Clp/*metabolism ; Protein Conformation ; Protein Isoforms/genetics ; *Proteolysis ; Pseudomonas aeruginosa/*metabolism ; Serine Endopeptidases/genetics/*metabolism ; Substrate Specificity ; }, abstract = {Caseinolytic proteases (Clp) are central to bacterial proteolysis and control cellular physiology and stress responses. They are composed of a double-ring compartmentalized peptidase (ClpP) and a AAA+ unfoldase (ClpX or ClpA/ClpC). Unlike many bacteria, the opportunistic pathogen Pseudomonas aeruginosa contains two ClpP homologs: ClpP1 and ClpP2. The specific functions of these homologs, however, are largely elusive. Here, we report that the active form of PaClpP2 is a part of a heteromeric PaClpP17 P27 tetradecamer that is required for proper biofilm development. PaClpP114 and PaClpP17 P27 complexes exhibit distinct peptide cleavage specificities and interact differentially with P. aeruginosa ClpX and ClpA. Crystal structures reveal that PaClpP2 has non-canonical features in its N- and C-terminal regions that explain its poor interaction with unfoldases. However, experiments in vivo indicate that the PaClpP2 peptidase active site uniquely contributes to biofilm development. These data strongly suggest that the specificity of different classes of ClpP peptidase subunits contributes to the biological outcome of proteolysis. This specialized role of PaClpP2 highlights it as an attractive target for developing antimicrobial agents that interfere specifically with late-stage P. aeruginosa development.}, } @article {pmid33231303, year = {2021}, author = {Tonon, CC and Panariello, BHD and Spolidorio, DMP and Gossweiler, AG and Duarte, S}, title = {Antibiofilm effect of ozonized physiological saline solution on peri-implant-related biofilm.}, journal = {Journal of periodontology}, volume = {92}, number = {8}, pages = {1151-1162}, doi = {10.1002/JPER.20-0333}, pmid = {33231303}, issn = {1943-3670}, support = {R21 DE028929/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; Chlorhexidine/pharmacology ; *Dental Implants ; Fusobacterium nucleatum ; Humans ; *Peri-Implantitis/drug therapy ; Porphyromonas gingivalis ; Saline Solution ; Titanium ; }, abstract = {BACKGROUND: Removal of dental plaque and local application of local chemical adjuncts, such as chlorhexidine (CHX), have been used to control and treat peri-implant disease. However, these methods can damage the surface properties of the implants or promote bacterial resistance. The application of ozone as an adjunctive treatment represents a new approach in the management of peri-implantitis. Thus, the purpose of this study was to evaluate the antimicrobial effect of ozonized physiological saline solution in different concentrations against oral biofilms developed on titanium surface.

METHODS: Single and multi-species biofilms of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus oralis were formed on titanium specimens for 5 days in anaerobic conditions. Biofilms were treated with ozonized saline solution at different concentrations (25, 50, and 80 μg/NmL), for 30 seconds and 1 minute. CHX (0.12%) and saline solution (0.89% NaCl) were used as positive and negative controls, respectively. Bacterial viability was quantified by colony forming units (CFU mL[-1]), and biofilm images were acquired by confocal laser scanning microscopy (CLSM). Data were analyzed by parametric test (ANOVA) with Tukey post-hoc test (P < 0.05).

RESULTS: Ozonized saline solution showed antibiofilm activity at a concentration of 80 μg/NmL for 30 seconds and 1 minute, reducing, mainly, Porphyromonas gingivalis viability, with 2.78 and 1.7 log10 CFU mL[-1] of reduction in both single and multi-species biofilms, respectively, when compared to the control (saline), whereas CHX reduced 1.4 and 1.2 log10 CFU mL[-1] .

CONCLUSION: Ozonized saline solution has antibiofilm activity, with better effect when applied for 1 minute at 80 μg/NmL, being a promising candidate therapy for the treatment of peri-implant diseases.}, } @article {pmid33230594, year = {2021}, author = {Paul, P and Chakraborty, P and Chatterjee, A and Sarker, RK and Dastidar, DG and Kundu, T and Sarkar, N and Das, A and Tribedi, P}, title = {1,4-Naphthoquinone accumulates reactive oxygen species in Staphylococcus aureus: a promising approach towards effective management of biofilm threat.}, journal = {Archives of microbiology}, volume = {203}, number = {3}, pages = {1183-1193}, pmid = {33230594}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; Naphthoquinones/*pharmacology ; Reactive Oxygen Species/*metabolism ; Staphylococcal Infections/prevention & control ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus, a Gram-positive opportunistic microorganism, promotes pathogenicity in the human host through biofilm formation. Microorganisms associated with biofilm often exhibit drug-resistance property that poses a major threat to public healthcare. Thus, the exploration of new therapeutic approaches is the need of the hour to manage biofilm-borne infections. In the present study, efforts are put together to test the antimicrobial as well as antibiofilm activity of 1,4-naphthoquinone against Staphylococcus aureus. The result showed that the minimum bactericidal concentration (MBC) of this compound was found to be 100 µg/mL against Staphylococcus aureus. In this regard, an array of experiments (crystal violet, biofilm protein measurement, and microscopic analysis) related to biofilm assay were conducted with the sub-MBC concentrations (1/20 and 1/10 MBC) of 1,4-naphthoquinone. All the results of biofilm assay demonstrated that these tested concentrations (1/20 and 1/10 MBC) of the compound (1,4-naphthoquinone) showed a significant reduction in biofilm development by Staphylococcus aureus. Moreover, the tested concentrations (1/20 and 1/10 MBC) of the compound (1,4-naphthoquinone) were able to reduce the microbial motility of Staphylococcus aureus that might affect the development of biofilm. Further studies revealed that the treatment of 1,4-naphthoquinone to the organism was found to increase the cellular accumulation of reactive oxygen species (ROS) that resulted in the inhibition of biofilm formation by Staphylococcus aureus. Hence, it can be concluded that 1,4-naphthoquinone might be considered as a promising compound towards biofilm inhibition caused by Staphylococcus aureus.}, } @article {pmid33230270, year = {2020}, author = {Latka, A and Drulis-Kawa, Z}, title = {Advantages and limitations of microtiter biofilm assays in the model of antibiofilm activity of Klebsiella phage KP34 and its depolymerase.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {20338}, pmid = {33230270}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Capsules/drug effects ; Bacteriophages/*enzymology ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Drug Discovery/*methods ; Drug Resistance, Multiple, Bacterial/drug effects ; Glycoside Hydrolases/*pharmacology ; Klebsiella pneumoniae/*drug effects/*physiology/virology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Viral Proteins/*pharmacology ; Virion/enzymology ; }, abstract = {One of the potential antibiofilm strategies is to use lytic phages and phage-derived polysaccharide depolymerases. The idea is to uncover bacteria embedded in the biofilm matrix making them accessible and vulnerable to antibacterials and the immune system. Here we present the antibiofilm efficiency of lytic phage KP34 equipped with virion-associated capsule degrading enzyme (depolymerase) and its recombinant depolymerase KP34p57, depolymerase-non-bearing phage KP15, and ciprofloxacin, separately and in combination, using a multidrug-resistant K. pneumoniae biofilm model. The most effective antibiofilm agents were (1) phage KP34 alone or in combination with ciprofloxacin/phage KP15, and (2) depolymerase KP34p57 with phage KP15 and ciprofloxacin. Secondly, applying the commonly used biofilm microtiter assays: (1) colony count, (2) LIVE/DEAD BacLight Bacterial Viability Kit, and (3) crystal violet (CV) biofilm staining, we unravelled the main advantages and limitations of the above methods in antibiofilm testing. The diverse mode of action of selected antimicrobials strongly influenced obtained results, including a false positive enlargement of biofilm mass (CV staining) while applying polysaccharide degrading agents. We suggest that to get a proper picture of antimicrobials' effectiveness, multiple examination methods should be used and the results must be read considering the principle of each technique and the antibacterial mechanism.}, } @article {pmid33228634, year = {2020}, author = {Motlhatlego, KE and Abdalla, MA and Leonard, CM and Eloff, JN and McGaw, LJ}, title = {Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation.}, journal = {BMC complementary medicine and therapies}, volume = {20}, number = {1}, pages = {358}, pmid = {33228634}, issn = {2662-7671}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Chlorocebus aethiops ; Diarrhea/*drug therapy ; Mannosides/*pharmacology ; Plant Extracts/*pharmacology ; Plant Leaves ; South Africa ; Vero Cells ; }, abstract = {BACKGROUND: Diarrhoea is a major health issue in both humans and animals and may be caused by bacterial, viral and fungal infections. Previous studies highlighted excellent activity of Newtonia buchananii and N. hildebrandtii leaf extracts against bacterial and fungal organisms related to diarrhoea-causing pathogens. The aim of this study was to isolate the compound(s) responsible for antimicrobial activity and to investigate efficacy of the extracts and purified compound against bacterial biofilms.

METHODS: The acetone extract of N. buchananii leaf powder was separated by solvent-solvent partitioning into eight fractions, followed by bioassay-guided fractionation for isolation of antimicrobial compounds. Antibacterial activity testing was performed using a broth microdilution assay. The cytotoxicity was evaluated against Vero cells using a colorimetric MTT assay. A crystal violet method was employed to test the inhibitory effect of acetone, methanol: dichloromethane and water (cold and hot) extracts of N. buchananii and N. hildebrandtii leaves and the purified compound on biofilm formation of Pseudomonas aeruginosa, Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus.

RESULTS: Myricetin-3-o-rhamnoside (myricitrin) was isolated for the first time from N. buchananii. Myricitrin was active against B. cereus, E. coli and S. aureus (MIC = 62.5 μg/ml in all cases). Additionally, myricitrin had relatively low cytotoxicity with IC50 = 104 μg/ml. Extracts of both plant species had stronger biofilm inhibitory activity against Gram-positive than Gram-negative bacteria. The most sensitive bacterial strains were E. faecalis and S. aureus. The cold and hot water leaf extracts of N. buchananii had antibacterial activity and were relatively non-cytotoxic with selectivity index values of 1.98-11.44.

CONCLUSIONS: The purified compound, myricitrin, contributed to the activity of N. buchananii but it is likely that synergistic effects play a role in the antibacterial and antibiofilm efficacy of the plant extract. The cold and hot water leaf extracts of N. buchananii may be developed as potential antibacterial and antibiofilm agents in the natural treatment of gastrointestinal disorders including diarrhoea in both human and veterinary medicine.}, } @article {pmid33228524, year = {2020}, author = {Yamasaki, R and Kawano, A and Yoshioka, Y and Ariyoshi, W}, title = {Rhamnolipids and surfactin inhibit the growth or formation of oral bacterial biofilm.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {358}, pmid = {33228524}, issn = {1471-2180}, support = {19K24102//Japan Society for the Promotion of Science/ ; 20K18485//Japan Society for the Promotion of Science/ ; }, mesh = {Bacteria/classification/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Glycolipids/*pharmacology ; Lipopeptides/*pharmacology ; Mouth Diseases/microbiology ; Species Specificity ; Surface-Active Agents/pharmacology ; }, abstract = {BACKGROUND: Bacteria survive in various environments by forming biofilms. Bacterial biofilms often cause significant problems to medical instruments and industrial processes. Techniques to inhibit biofilm formation are essential and have wide applications. In this study, we evaluated the ability of two types of biosurfactants (rhamnolipids and surfactin) to inhibit growth and biofilm formation ability of oral pathogenic bacteria such as Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Streptococcus sanguinis.

RESULTS: Rhamnolipids inhibited the growth and biofilm formation ability of all examined oral bacteria. Surfactin showed effective inhibition against S. sanguinis ATCC10556, but lower effects toward A. actinomycetemcomitans Y4 and S. mutans UA159. To corroborate these results, biofilms were observed by scanning electron microscopy (SEM) and confocal microscopy. The observations were largely in concordance with the biofilm assay results. We also attempted to determine the step in the biofilm formation process that was inhibited by biosurfactants. The results clearly demonstrated that rhamnolipids inhibit biofilm formation after the initiation process, however, they do not affect attachment or maturation.

CONCLUSIONS: Rhamnolipids inhibit oral bacterial growth and biofilm formation by A. actinomycetemcomitans Y4, and may serve as novel oral drug against localized invasive periodontitis.}, } @article {pmid33228110, year = {2020}, author = {Terán, LC and Distefano, M and Bellich, B and Petrosino, S and Bertoncin, P and Cescutti, P and Sblattero, D}, title = {Proteomic Studies of the Biofilm Matrix including Outer Membrane Vesicles of Burkholderia multivorans C1576, a Strain of Clinical Importance for Cystic Fibrosis.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33228110}, issn = {2076-2607}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; 1R01GM123283-01//This publication was supported by an agreement with Cornell University, under Prime Agreement 1R01GM123283-01 from US National Institutes of Health DHHS./ ; }, abstract = {Biofilms are aggregates of microbial cells encased in a highly hydrated matrix made up of self-produced extracellular polymeric substances (EPS) which consist of polysaccharides, proteins, nucleic acids, and lipids. While biofilm matrix polysaccharides are unraveled, there is still poor knowledge about the identity and function of matrix-associated proteins. With this work, we performed a comprehensive proteomic approach to disclose the identity of proteins associated with the matrix of biofilm-growing Burkholderia multivorans C1576 reference strain, a cystic fibrosis clinical isolate. Transmission electron microscopy showed that B. multivorans C1576 also releases outer membrane vesicles (OMVs) in the biofilm matrix, as already demonstrated for other Gram-negative species. The proteomic analysis revealed that cytoplasmic and membrane-bound proteins are widely represented in the matrix, while OMVs are highly enriched in outer membrane proteins and siderophores. Our data suggest that cell lysis and OMVs production are the most important sources of proteins for the B. multivorans C1576 biofilm matrix. Of note, some of the identified proteins are lytic enzymes, siderophores, and proteins involved in reactive oxygen species (ROS) scavenging. These proteins might help B. multivorans C1576 in host tissue invasion and defense towards immune system assaults.}, } @article {pmid33228072, year = {2020}, author = {Kwiecińska-Piróg, J and Przekwas, J and Majkut, M and Skowron, K and Gospodarek-Komkowska, E}, title = {Biofilm Formation Reducing Properties of Manuka Honey and Propolis in Proteus mirabilis Rods Isolated from Chronic Wounds.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33228072}, issn = {2076-2607}, support = {DS-UPB-research task UPB 536//Nicholaus Copernicus University in Toruń/ ; }, abstract = {Chronic wound infections are difficult to manage because of the biofilm formation in the wound environment. New measures for eliminating infections are necessary to increase the chance of wound healing. Apitherapy may be the new solution. The aim of this study was to assess the prevalence of wound infection factors and to examine the impact of Manuka honey and ethanol extract of propolis on biofilm formation of Proteus mirabilis isolated from chronic wound infections. According to the findings, the most frequent factors of infection are Staphylococcus aureus (46.1%), Pseudomonas aeruginosa (35.0%), and Proteus mirabilis (10.6%). Minimal inhibitory concentration and minimal bactericidal concentration values were assigned using the microbroth dilution test according to the Clinical and Laboratory Standards Institute. Biofilm of Proteus mirabilis isolates was formed in 96-well polystyrene plates and treated with Manuka honey (concentrations from 1.88% to 30.0%) and ethanol extract of propolis (1.0% to 40.0%). After 24 h, the biofilm viability was expressed by formazan absorbance (λ = 470 nm). Manuka honey reduced the biofilm viability in all, and ethanol extract of propolis in most, of the concentrations tested. Ethanol extract of propolis at the concentrations of 20.0% and 40.0%, reduced biofilm viability stronger than ethanol itself. With these results comes the conclusion that these substances can reduce biofilm formation.}, } @article {pmid33227365, year = {2021}, author = {Bekkal Brikci Benhabib, O and Boucherit-Otmani, Z and Boucherit, K and Djediat, C}, title = {Interaction in a dual-species biofilm of Candida albicans and Candida glabrata co-isolated from intravascular catheter.}, journal = {Microbial pathogenesis}, volume = {152}, number = {}, pages = {104613}, doi = {10.1016/j.micpath.2020.104613}, pmid = {33227365}, issn = {1096-1208}, mesh = {Algeria ; Biofilms ; *Candida albicans ; *Candida glabrata ; Catheters ; Humans ; }, abstract = {The use of catheters for vascular access may be associated with colonization by Candida species and their biofilm-forming ability. The latter can harbor two or more species of Candida yeast. In the sense, we conducted our study at the University Hospital of Tlemcen in west Algeria at the neuro-surgery unit, that aims (or which aims) to evaluate the ability to form mixed biofilm by dual-species Candida albicans/Candida glabrata co-isolated from intravascular catheters and their interaction in biofilm. That is the first report in Algeria. During this study, we took photographic images by scanning electron microscopy of 3 catheters implanted before 48 h and co-colonized by dual-species. From all taken samples, 34 catheters were altered by yeasts from which three were co-colonized by two Candida species and C. albicans established synergistic and competitive interactions with C. glabrata species in mixed biofilm tested.}, } @article {pmid33227279, year = {2021}, author = {Engevik, MA and Danhof, HA and Auchtung, J and Endres, BT and Ruan, W and Bassères, E and Engevik, AC and Wu, Q and Nicholson, M and Luna, RA and Garey, KW and Crawford, SE and Estes, MK and Lux, R and Yacyshyn, MB and Yacyshyn, B and Savidge, T and Britton, RA and Versalovic, J}, title = {Fusobacteriumnucleatum Adheres to Clostridioides difficile via the RadD Adhesin to Enhance Biofilm Formation in Intestinal Mucus.}, journal = {Gastroenterology}, volume = {160}, number = {4}, pages = {1301-1314.e8}, pmid = {33227279}, issn = {1528-0012}, support = {U01 AI124290/AI/NIAID NIH HHS/United States ; P30 DK123704/DK/NIDDK NIH HHS/United States ; F32 AI136404/AI/NIAID NIH HHS/United States ; K01 DK123195/DK/NIDDK NIH HHS/United States ; R01 AI123278/AI/NIAID NIH HHS/United States ; P30 DK056338/DK/NIDDK NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Bacterial Adhesion/immunology ; Biofilms ; Bioreactors/microbiology ; Clostridioides difficile/genetics/immunology/metabolism/*pathogenicity ; Clostridium Infections/*immunology/microbiology ; Feces/microbiology ; Flagella/genetics/metabolism ; Fusobacterium nucleatum/*immunology/metabolism ; Gastrointestinal Microbiome/*immunology ; HT29 Cells ; Humans ; Intestinal Mucosa/immunology/metabolism/microbiology/pathology ; Mucin-2/metabolism ; }, abstract = {BACKGROUND & AIMS: Although Clostridioides difficile infection (CDI) is known to involve the disruption of the gut microbiota, little is understood regarding how mucus-associated microbes interact with C difficile. We hypothesized that select mucus-associated bacteria would promote C difficile colonization and biofilm formation.

METHODS: To create a model of the human intestinal mucus layer and gut microbiota, we used bioreactors inoculated with healthy human feces, treated with clindamycin and infected with C difficile with the addition of human MUC2-coated coverslips.

RESULTS: C difficile was found to colonize and form biofilms on MUC2-coated coverslips, and 16S rRNA sequencing showed a unique biofilm profile with substantial cocolonization with Fusobacterium species. Consistent with our bioreactor data, publicly available data sets and patient stool samples showed that a subset of patients with C difficile infection harbored high levels of Fusobacterium species. We observed colocalization of C difficile and F nucleatum in an aggregation assay using adult patients and stool of pediatric patients with inflammatory bowel disease and in tissue sections of patients with CDI. C difficile strains were found to coaggregate with F nucleatum subspecies in vitro; an effect that was inhibited by blocking or mutating the adhesin RadD on Fusobacterium and removal of flagella on C difficile. Aggregation was shown to be unique between F nucleatum and C difficile, because other gut commensals did not aggregate with C difficile. Addition of F nucleatum also enhanced C difficile biofilm formation and extracellular polysaccharide production.

CONCLUSIONS: Collectively, these data show a unique interaction of between pathogenic C difficile and F nucleatum in the intestinal mucus layer.}, } @article {pmid33227214, year = {2021}, author = {Assisi, C and Forauer, E and Oliver, HF and Etter, AJ}, title = {Genomic and Transcriptomic Analysis of Biofilm Formation in Persistent and Transient Listeria monocytogenes Isolates from the Retail Deli Environment Does Not Yield Insight into Persistence Mechanisms.}, journal = {Foodborne pathogens and disease}, volume = {18}, number = {3}, pages = {179-188}, doi = {10.1089/fpd.2020.2817}, pmid = {33227214}, issn = {1556-7125}, mesh = {Animals ; *Biofilms ; Food Microbiology/*methods ; Genome, Bacterial ; Listeria monocytogenes/genetics/isolation & purification/*physiology ; Meat Products/*microbiology ; Transcriptome ; }, abstract = {Persistence of Listeria monocytogenes in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads, and cheeses. We previously discovered strong evidence of L. monocytogenes persistence in delis across multiple states. We hypothesized that this was correlated with isolates' innate characteristics, such as biofilm-forming capacity or gene differences. To test this hypothesis, we sequenced the genomes of 21 L. monocytogenes isolates previously collected longitudinally from the retail deli environment. Isolates were chosen to represent varying attachment capacity and sanitizer tolerance as well as persistence or transience. We used single-nucleotide polymorphism analysis to characterize the isolates' genetic relationships and used BLAST to search the isolates' genomes for antibiotic resistance elements, quaternary ammonium tolerance genes, and stress survival islets. We further chose four isolates for RNA-sequencing analysis and compared their global biofilm transcriptome with their global planktonic transcriptome. We did not find genetic content that explained persistence. The presence of stress survival islet-1 correlated to increased attachment capacity (p < 0.05), but not persistence. Further, the presence of sanitizer tolerance elements was not significantly correlated with phenotypic sanitizer tolerance. Analysis of biofilm versus planktonic gene expression did not show the expected differences in gene expression patterns. Overall, L. monocytogenes persistence in the deli environment is likely a matter of poor sanitation and/or facility design, rather than isolates' biofilm-forming capacity, sanitizer tolerance, or genomic content.}, } @article {pmid33226719, year = {2021}, author = {Gupta, P and Pruthi, V and Poluri, KM}, title = {Mechanistic insights into Candida biofilm eradication potential of eucalyptol.}, journal = {Journal of applied microbiology}, volume = {131}, number = {1}, pages = {105-123}, doi = {10.1111/jam.14940}, pmid = {33226719}, issn = {1365-2672}, support = {CRG/2018/001329//Science and Engineering Research Board/ ; SB/YS/LS-380/2013//Science and Engineering Research Board/ ; BT/07/IYBA/2013-19//Department of Biotechnology , Ministry of Science and Technology/ ; DBT-RA Progam//Department of Biotechnology , Ministry of Science and Technology/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/physiology ; Candidiasis/microbiology ; Cell Cycle/drug effects ; Drug Resistance, Fungal/drug effects ; Eucalyptol/*pharmacology ; Humans ; Membrane Potential, Mitochondrial/drug effects ; Microbial Sensitivity Tests ; Reactive Oxygen Species/metabolism ; Transcription, Genetic/drug effects ; }, abstract = {AIM: Candida-associated fungal infections are prevalent in hospitalized and immune-compromised patients. Their biofilm architecture and high rate of antifungal resistance make treatment challenging. Eucalyptol (EPTL), a monoterpene majorly present in the essential oil of eucalyptus is well known for curing respiratory infections. Hence, the present study investigated the anti-biofilm efficacy of EPTL against the laboratory strains and clinical isolates of Candida to delineate its mode of action.

METHODS: The effect of EPTL on the viability, biofilm formation, and mature biofilm of Candida strains was studied. Furthermore, its effect on cell cycle arrest, mitochondrial membrane potential (MMP), ROS generation, germ tube formation, ergosterol content and transcriptional expression of selected genes was also investigated.

RESULTS: EPTL exhibited anti-biofilm activity against mature and developing biofilm of Candida albicans and Candida glabrata along with their clinical isolates. The biochemical components and enzyme activity were differentially modulated in EPTL-treated biofilm extracellular matrix. EPTL generated ROS and arrested cell cycle at the G1 /S phase in both the species, while altered MMP was recorded in C. glabrata. Transcriptional analysis evidenced for differential gene expression of selected ABC transporters, secreted hydrolytic enzymes, and cell wall biogenesis in C. albicans/C. glabrata upon treating with EPTL.

CONCLUSION: The current data on anti-biofilm activity of EPTL establish its candidacy for drug development or as an adjuvant with existing antifungal formulations.

Present investigation elucidates the mode of action of Eucalyptol as antifungal agent and would stand as a candidate for management of topical fungal infection.}, } @article {pmid33226500, year = {2021}, author = {Walther, C and Zumbülte, S and Faerber, CM and Wierichs, RJ and Meyer-Lueckel, H and Conrads, G and Henne, K and Esteves-Oliveira, M}, title = {Analysis of relative bacterial activity and lactate dehydrogenase gene expression of caries-associated bacteria in a site-specific natural biofilm: an ex vivo study.}, journal = {Clinical oral investigations}, volume = {25}, number = {6}, pages = {3669-3679}, pmid = {33226500}, issn = {1436-3771}, support = {(#39/17)//Medizinische Fakultät, RWTH Aachen University (DE)/ ; }, mesh = {Bacteria/genetics ; Biofilms ; *Dental Caries ; Dental Caries Susceptibility ; Gene Expression ; Humans ; *L-Lactate Dehydrogenase/genetics ; RNA, Ribosomal, 16S/genetics ; Streptococcus mutans/genetics ; }, abstract = {OBJECTIVES: Detecting bacterial activity is considered a promising approach to monitor shifts from symbiosis to dysbiosis in oral microbiome. The present study aimed at investigating both the relative bacterial activity and the lactate dehydrogenase (ldh) gene expression of caries-associated bacteria in a site-specific natural biofilm.

MATERIAL AND METHODS: Sixty subjects (age, mean ± SE: 30.1 ± 1.4) were allocated to two groups: caries-free subjects (CF) or caries-active subjects (CA). CF presented one sound surface (CFS, n = 30). CA presented two donor sites: a cavitated caries lesion (CAC, n = 30) and a sound reference surface (CAS, n = 30). Real-time quantitative PCR (q-PCR) on species or genus level and total bacteria was performed targeting the 16S gene, the 16S rRNA, the ldh gene, and the ldh mRNA (increasing 16S ribosomal RNA copy numbers can function as an indicator of increased energy metabolism). As the 16S rRNA abundance represents the number of ribosomes, while the 16S gene abundance represents the number of genomes, the quotient of the relative abundances functions as a measure for the relative bacterial activity (%).

RESULTS: Both lactobacilli and S. mutans showed the highest relative bacterial activity in CAC ((mean ± SE) 218 ± 60% and 61 ± 16%, respectively) and the lowest values for both sound reference surfaces (69 ± 48%; 8 ± 3%). Significant differences were found between CAC and CAS as well as between CAC and CFS for both lactobacilli and S. mutans (p < 0.05). The ldh gene expression of lactobacilli and S. mutans only showed moderate values in CAC (1.90E+03 ± 2.11E+03; 2.08E+04 ± 4.44E+04 transcripts/μl) and CFS (2.04E+03 ± 2.74E+03; 8.16E+03 ± 6.64E+03 transcripts/μl); consequently no significant differences were detected.

Caries-associated bacteria (lactobacilli and S. mutans) showed the highest relative bacterial activity in plaque of cavitated lesions, the lowest in sound surfaces, allowing the detection of a significant activity shift in health and disease for caries-active patients. However, no significant differences in ldh gene expression could be determined.}, } @article {pmid33225299, year = {2020}, author = {Chipenzi, T and Baloyi, G and Mudondo, T and Sithole, S and Fru Chi, G and Mukanganyama, S}, title = {An Evaluation of the Antibacterial Properties of Tormentic Acid Congener and Extracts From Callistemon viminalis on Selected ESKAPE Pathogens and Effects on Biofilm Formation.}, journal = {Advances in pharmacological and pharmaceutical sciences}, volume = {2020}, number = {}, pages = {8848606}, pmid = {33225299}, issn = {2633-4690}, abstract = {ESKAPE pathogens, namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, are responsible for a majority of all healthcare-acquired infections (HAI). The bacteria cause nosocomial infections in immunocompromised patients. Extracts from Callistemon viminalis have been shown to have antibacterial, antifungal, and anti-inflammatory activities. Tormentic acid congener, a pentacyclic triterpene saponin, was isolated from C. viminalis leaves. This study aimed to investigate the antibacterial effects of tormentic acid congener and leaf extracts on biofilm formation by A. baumannii, S. aureus, S. pyogenes, and P. aeruginosa. The antibacterial effects were determined by the microbroth dilution method, and ciprofloxacin was used as the standard antibacterial drug. Biofilm formation and detachment assays were performed using crystal violet staining. Production of extracellular polymeric DNA and polysaccharides from biofilms was also determined. Tormentic acid congener showed time-dependent antibacterial activity against P. aeruginosa with a MIC of 100 µg/ml and caused significant protein leakage. Antibacterial activity was found when tormentic acid congener was tested against both S. aureus and P. aeruginosa. The MICs were found to be 25 µg/ml and 12.5 µg/ml for P. aeruginosa and S. aureus cells, respectively. S. pyogenes was found to be susceptible to tormentic acid congener and the hydroethanolic extract with an MIC of 100 µg/ml and 25 µg/ml, respectively. A. baumannii was found not to be susceptible to the compound or the extracts. The compound and the extracts caused a significant decrease in the biofilm extracellular polysaccharide content of S. pyogenes. The extracts and tormentic acid congener caused detachment of biofilms and decreased the release of extracellular DNA and capsular polysaccharides from biofilms of P. aeruginosa and S. aureus. Tormentic acid congener and extracts, thus, have significant antibacterial and antibiofilm activities on these selected ESKAPE bacteria and can act as source lead compounds for the development of antibacterial triterpenoids.}, } @article {pmid33224261, year = {2020}, author = {Tseng, CY and Sun, MF and Li, TC and Lin, CT}, title = {Effect of Coptis chinensis on Biofilm Formation and Antibiotic Susceptibility in Mycobacterium abscessus.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2020}, number = {}, pages = {9754357}, pmid = {33224261}, issn = {1741-427X}, abstract = {Mycobacterium abscessus infections are notoriously difficult to be treated and newer treatment options are required. Coptis chinensis (C. chinensis) and its main compound berberine are frequently used to treat bacterial and viral infections. In this study, the susceptibility of M. abscessus to C. chinensis extract and berberine was assessed by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) evaluation. The effects of C. chinensis and berberine on biofilm formation and antibiotic susceptibility in M. abscessus were observed. C. chinensis at concentrations of MIC (1.5 mg/mL) and 2 × MIC (3.0 mg/mL) and berberine at ½ × MIC (0.125 mg/mL) demonstrated a strong inhibition of biofilm formation. Concentration of C. chinensis at ½ × MIC resulted in a significant reduction in MICs of trimethoprim/sulfamethoxazole (TMP/SXT), clarithromycin (CLA), and linezolid (LZD). Similarly, ½ × MIC berberine had a significant effect on the MIC reductions of nine antibiotics including TMP/SXT, CLA, and LZD. Notably, the resistance level MIC of LZD against M. abscessus was reversed to a susceptible level by treatment with either C. chinensis or berberine. Therefore, C. chinensis and berberine have the potential to produce a synergistic antimycobacterial effect, reduce biofilm formation, and decrease antibacterial resistance to LZD in M. abscessus.}, } @article {pmid33224216, year = {2020}, author = {Abdollahi, S and Tofighi, Z and Babaee, T and Shamsi, M and Rahimzadeh, G and Rezvanifar, H and Saeidi, E and Mohajeri Amiri, M and Saffari Ashtiani, Y and Samadi, N}, title = {Evaluation of Anti-oxidant and Anti-biofilm Activities of Biogenic Surfactants Derived from Bacillus amyloliquefaciens and Pseudomonas aeruginosa.}, journal = {Iranian journal of pharmaceutical research : IJPR}, volume = {19}, number = {2}, pages = {115-126}, pmid = {33224216}, issn = {1735-0328}, abstract = {Biosurfactants, the microbial originated surface active agents, can modify the physicochemical properties of surfaces and reduce the bacterial adhesion via changing bacterial adhesion interactions on surfaces. They were also able to block oxidative chain reactions and might show antioxidant properties. The goal of this study was to evaluate the antioxidant and antibiofilm activities of biosurfactants which were derived from two autochthonous biosurfactant-producing strains, Bacillus amyloliquefaciens NS6 (surfactin), and Pseudomonas aeruginosa MN1 (rhamnolipids). Their antioxidant activities were determined by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Ferric thiocyanate (FTC) assay was used for determination of their lipid peroxidation inhibition capacity. Their effect to reduce the adhesion of Streptococcus mutans on polystyrene surfaces and disruption of its pre-formed biofilms were also investigated. Our results indicated that surfactin showed higher antioxidant activity than rhamnolipids and showed relatively similar efficiency to BHA that suggests it as a good alternative for synthetic antioxidants. In other hand, rhamnolipid conditioned surfaces showed higher antiadhesive and antibiofilm activity in comparison with surfactin treated surfaces.}, } @article {pmid33224124, year = {2020}, author = {Yu, J and Jiang, F and Zhang, F and Pan, Y and Wang, J and Han, P and Tang, J and Shen, H}, title = {Virtual Screening for Novel SarA Inhibitors to Prevent Biofilm Formation of Staphylococcus aureus in Prosthetic Joint Infections.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {587175}, pmid = {33224124}, issn = {1664-302X}, abstract = {Staphylococcus aureus is one of the predominant causes of periprosthetic joint infections (PJIs). Bacterial adhesion and biofilm formation are important factors in the pathogenesis of PJIs. S. aureus biofilm formation is regulated by several factors, including S. aureus regulator A (SarA). Previous studies have found that SarA mutants have limited ability to develop biofilms. In this study, we identified a SarA-targeting antibiofilm compound, ZINC00990144, and evaluated its efficacy and toxicity. According to static biofilm assay, the antibiofilm ability of the compound was concentration dependent. ZINC00990144 reduced biofilm in multiple strains by 40-86% at a concentration of 11.5 μM. Additionally, ZINC00990144 inhibited biofilm formation on different orthopedic implant materials including Titanium and UHMWPE disc. Furthermore, quantitative polymerase chain reaction results demonstrated that ZINC00990144 upregulated the expression of S. aureus exoproteases to inhibit the formation of biofilms. Moreover, ZINC00990144 prevented biofilm formation when exposed to sub-inhibitory doses of vancomycin, which is known to promote biofilm formation. CCK-8 results demonstrated ZINC00990144 has no significant effect on cell viability at concentration of 11.5 μM or below. Finally, we verified the antibiofilm function of the compound in vivo using implant infection mice model with/without exposure to sub-inhibitory vancomycin. In conclusion, ZINC00990144 acts by modulating between biofilm and planktonic state of S. aureus instead of being bactericidal. Therefore, it has the potential to be used in combination with other antibiotics to prevent PJIs.}, } @article {pmid33221512, year = {2020}, author = {Qi, X and Wang, S and Li, T and Wang, X and Jiang, Y and Zhou, Y and Zhou, X and Huang, X and Liang, P}, title = {An electroactive biofilm-based biosensor for water safety: Pollutants detection and early-warning.}, journal = {Biosensors & bioelectronics}, volume = {173}, number = {}, pages = {112822}, doi = {10.1016/j.bios.2020.112822}, pmid = {33221512}, issn = {1873-4235}, abstract = {Besides serving in wastewater treatment and energy generation fields, electroactive biofilm (EAB) has been employed as a sensitive bio-elements in a biosensor to monitor water quality by delivering electrical signals without additional mediators. Increasing studies have applied EAB-based biosensor in specific pollutant detection, typically biochemical oxygen demand (BOD) detection, as well as in early-warning of composite pollutants. Based on a comprehensive review of literatures, this study reveals how EAB outputs electrical signal, how we can evaluate and improve this performance, and what information we can expect from EAB-based biosensor. Since BOD detection and early-warning are normally confusing, this study manages to differentiate these two applications through distinguished purposes and metrics. Based on the introductions of progresses and applications of EAB-based biosensors so far, several novel strategies toward the future development of EAB-based biosensors are proposed.}, } @article {pmid33220897, year = {2021}, author = {Moon, DJ and Deva, AK}, title = {Adverse Events Associated with Breast Implants: The Role of Bacterial Infection and Biofilm.}, journal = {Clinics in plastic surgery}, volume = {48}, number = {1}, pages = {101-108}, doi = {10.1016/j.cps.2020.09.009}, pmid = {33220897}, issn = {1558-0504}, } @article {pmid33220541, year = {2021}, author = {Yuan, J and Yuan, H and Huang, S and Liu, L and Fu, F and Zhang, Y and Cheng, F and Li, J}, title = {Comprehensive performance, bacterial community structure of single-chamber microbial fuel cell affected by COD/N ratio and physiological stratifications in cathode biofilm.}, journal = {Bioresource technology}, volume = {320}, number = {Pt B}, pages = {124416}, doi = {10.1016/j.biortech.2020.124416}, pmid = {33220541}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Biological Oxygen Demand Analysis ; Electricity ; Electrodes ; In Situ Hybridization, Fluorescence ; Wastewater ; }, abstract = {This study compares the effects and bacterial community structure of single-chamber microbial fuel cells (MFCs) in the treatment of NH4[+]-containing wastewater with different chemical oxygen demand (COD)/N ratios, whilst simultaneously conducting stratification research on the cathode biofilm. To this end, five nitrifier pre-enriched single-chamber MFC reactors are established to treat five different COD/N wastewaters, respectively. The results show that MFCs with low COD/N have better NH4[+]-N removal, electrochemical performance, but the removal stability and COD removal effect are lower than MFCs with high COD/N. High-throughput sequencing reveals that the anode community structure is weakly affected by the COD/N and is dominated by Geobacter; however, the cathode community is complex and susceptible to the COD/N. Furthermore, the pH profile in the cathode biofilm is characterized by a pH microelectrode and fluorescence in situ hybridization (FISH) is used to confirm that the distribution trend of nitrifiers and denitrifiers in cathode biofilm.}, } @article {pmid33220013, year = {2021}, author = {Zhao, Z and Li, H and Tao, X and Xie, Y and Yang, L and Mao, ZW and Xia, W}, title = {Light-Triggered Nitric Oxide Release by a Photosensitizer to Combat Bacterial Biofilm Infections.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {27}, number = {17}, pages = {5453-5460}, doi = {10.1002/chem.202004698}, pmid = {33220013}, issn = {1521-3765}, support = {22022706//National Natural Science Foundation of China/ ; 21877131//National Natural Science Foundation of China/ ; 91953117//National Natural Science Foundation of China/ ; 2019A1515011156//Natural Science Foundation of Guangdong Province/ ; IRT-17R111//Ministry of Education of the People's Republic of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacterial Infections/drug therapy ; Biofilms ; Humans ; Nitric Oxide ; *Photosensitizing Agents/pharmacology ; Pseudomonas aeruginosa ; }, abstract = {Bacterial biofilms are a serious global health concern, often responsible for persistent infections. New strategies to prevent and treat bacterial infections by eradication of the biofilms are urgently needed. A novel ruthenium-based compound is reported in this study that functions as both a boronic acid-decorated photosensitizer (PS) and a light-triggered nitric oxide (NO) releasing agent. The compound can selectively attach to the bacterial membrane and biofilms and it is highly potent at eradicating Pseudomonas aeruginosa biofilms through the simultaneous release of NO and reactive oxygen species (ROS). The compound, which is more effective than clinical antibiotic tobramycin, also has excellent bacterial specificity and shows no significant cytotoxicity to human cells. The results reveal potential applications of this innovative dual-functional photoactivated ruthenium compound to combat bacterial biofilm infections.}, } @article {pmid33215521, year = {2020}, author = {da Silva, CR and S Campos, R and de A Neto, JB and Sampaio, LS and do Nascimento, FB and do Av Sá, LG and Cândido, TM and Magalhães, HI and da Cruz, EH and da Silva Júnior, EN and de Moraes, MO and Cavalcanti, BC and Silva, J and Marinho, ES and Júnior, HV}, title = {Antifungal activity of β-lapachone against azole-resistant Candida spp. and its aspects upon biofilm formation.}, journal = {Future microbiology}, volume = {15}, number = {}, pages = {1543-1554}, doi = {10.2217/fmb-2020-0011}, pmid = {33215521}, issn = {1746-0921}, mesh = {Antifungal Agents/*pharmacology ; Azoles/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Candidiasis/drug therapy/microbiology ; *Drug Resistance, Fungal ; Humans ; Microbial Sensitivity Tests ; Naphthoquinones/*pharmacology ; }, abstract = {Aim: The purpose of this study was to assess the antifungal effect of β-lapachone (β-lap) on azole-resistant strains of Candida spp. in both planktonic and biofilm form. Materials & methods: The antifungal activity of β-lap was evaluated by broth microdilution, flow cytometry and the comet assay. The cell viability of the biofilms was assessed using the MTT assay. Results: β-lap showed antifungal activity against resistant strains of Candida spp. in planktonic form. In addition, β-lap decreased the viability of mature biofilms and inhibited the formation of biofilms in vitro. Conclusion: β-lap showed antifungal activity against Candida spp., suggesting that the compound can be utilized as an adjunct agent in the treatment of candidiasis.}, } @article {pmid33215491, year = {2020}, author = {Amaya Arbeláez, MI and Vergani, CE and Barbugli, PA and Pavarina, AC and Sanitá, PV and Jorge, JH}, title = {Long-Term Effect of Daily Chemical Disinfection on Surface Topography and Candida Albicans Biofilm Formation on Denture Base and Reline Acrylic Resins.}, journal = {Oral health & preventive dentistry}, volume = {18}, number = {1}, pages = {999-1010}, doi = {10.3290/j.ohpd.a45521}, pmid = {33215491}, issn = {1757-9996}, mesh = {Acrylic Resins ; Biofilms ; *Candida albicans ; Denture Bases ; Denture Cleansers/pharmacology ; *Disinfection ; Materials Testing ; Surface Properties ; }, abstract = {PURPOSE: This study investigated the effect of long-term daily chemical disinfection on the topographic and Candida albicans biofilm formation on a denture base resin and a reline acrylic resin.

MATERIAL AND METHODS: Circular samples (14 × 1.2 mm) were fabricated from a denture base (Vipi Wave) and reline acrylic resins (Tokuyama Rebase Fast II). Samples were kept in 50 ml of distilled water (48 h at 37°C). Subsequently, the samples were immersed in five different solutions: 0.5% sodium hypochlorite; 3.8% sodium perborate; 2% chlorhexidine gluconate; apple vinegar containing 4% maleic acid; and distilled water (control group). The specimen was immersed in the solutions for 8 h daily and transferred to distilled water at 37°C for more 16 h. The surface topographic and Candida albicans (ATCC 90028) biofilm formation were evaluated at baseline (before chemical disinfection) and after 1, 3 and 6 months of immersion. The surface topographic was evaluated by arithmetical roughness average (Ra) and scanning electron microscope (SEM), while the biofilm formation was evaluated by colony-forming units (CFU/ml) method and Alamar Blue assay (cell metabolism). The results were evaluated by three-way analysis of variance (ANOVAs) and post-hoc tests (α = 0.05).

RESULTS: The results showed statistically significant effects from the type of acrylic resin (p = 0.029) and time (p <0.001) on the roughness of the specimen. In general, the reline resin had higher roughness than the denture base resin. In addition, the roughness of the samples after 1, 3 and 6 months of immersion in the cleaning solutions was higher than at baseline. In relation to the microbiological assays, there were no statistically significant differences (p >0.055) in the CFU/ml values of the biofilms among the different resins, periods of time and cleaning solutions. Considering the metabolism of the cells within the biofilms, the results showed that, at baseline, it was statistically significantly higher (p <0.05) than after 1, 3 and 6 months of storage. The SEM images showed that all disinfectant solutions provided surface changes of both acrylic resins (base and reline) after 1, 3 and 6 months of immersion.

CONCLUSIONS: The roughness of both acrylic resins was affected by the disinfection in all cleaning agents, increasing over time, and this effect was more evident in the reline acrylic resin group. This surface change was also observed in the SEM images. While the number of cells within the biofilms was not affected by immersion in the cleaning agents, their metabolism was lower after 1, 3 and 6 months of immersion.}, } @article {pmid33215489, year = {2020}, author = {Jeyakumar, J and Sculean, A and Eick, S}, title = {Anti-biofilm Activity of Oral Health-care Products Containing Chlorhexidine Digluconate and Citrox.}, journal = {Oral health & preventive dentistry}, volume = {18}, number = {1}, pages = {981-990}, doi = {10.3290/j.ohpd.a45437}, pmid = {33215489}, issn = {1757-9996}, mesh = {Biofilms ; *Chlorhexidine/analogs & derivatives/pharmacology ; Mouthwashes/pharmacology ; *Oral Health ; }, abstract = {PURPOSE: To analyze in vitro new formulations with Citrox and chlorhexidine digluconate (CHX) regarding their antibacterial activity against planktonic bacteria and their potential to inhibit biofilm formation or to act on existing biofilms.

MATERIALS AND METHODS: Five oral health care products with 0.05%-0.5% CHX formulations (four rinses and one gel) were compared with Citrox preparations and additive-free CHX solutions. The minimal inhibitory concentrations (MIC) were determined against 13 oral bacteria associated with caries or periodontitis. Further, the activity on retarding biofilm formation and on existing biofilms was analyzed; both a 'cariogenic' (5 species) and a 'periodontal' (12 species) biofilm were included.

RESULTS: The MIC values did not differ between the CHX mouthrinse/gel formulations and the respective additive-free CHX solutions. Citrox was active against selected periodontopathogens (e.g. Porphyromonas gingivalis). The CHX formulations more effectively retarded biofilm formation than did solutions with the same concentration of CHX but without additives. The anti-biofilm activities depended on the CHX concentration in the formulations. Both CHX solutions and formulations (rinse and gel) were only slightly active on an already formed biofilm. Citrox did not exert any anti-biofilm effect.

CONCLUSION: The present in vitro data support the anti-biofilm activity of the novel CHX, Citrox, poly-L-lysine and xylitol oral health-care formulations. Further studies are warranted to confirm the present findings in various clinical settings.}, } @article {pmid33214988, year = {2020}, author = {Shadbad, MA and Kafil, HS and Rezaee, MA and Farzami, MR and Dehkharghani, AD and Sadeghi, J and Gholizadeh, P and Khodaei, F and Aghazadeh, M}, title = {Streptococcus agalactiae clinical isolates in Northwest Iran: antibiotic susceptibility, molecular typing, and biofilm formation.}, journal = {GMS hygiene and infection control}, volume = {15}, number = {}, pages = {Doc23}, pmid = {33214988}, issn = {2196-5226}, abstract = {Background: Group B Streptococcus (S. agalactiae) is one of the colonizing bacteria in pregnant women which can be a causative agent of meningitis and neonatal sepsis. This organism has also been increasingly related to invasive infections in non-pregnant adults. Objective: In present study, we aimed to characterize the clonality of biofilm-producing S. agalactiae isolates from various sources from two different clinical laboratories in Tehran, Iran. Materials and Methods: S. agalactiae isolates were collected from community-acquired (CA) and hospital-acquired (HA) infections in pregnant and non-pregnant adults. The antimicrobial susceptibility patterns and biofilm formation ability were determined. In addition, pulse field gel electrophoresis (PFGE) was used to verify the clonal diversity of isolates. Results: Out of the 87 isolates, 15 (16.6%) formed biofilm. The antibiotic resistance rate was 98.85% for clindamycin, 98.85% for tetracycline, followed by 29.88% for erythromycin, 9.19% for moxifloxacin and 6.89% for levofloxacin. The PFGE patterns revealed a total of 16 different clusters consisting of 6 single types (STs). Conclusion: This study evaluated the biofilm formation of clinical S. agalactiae, which may be a step towards understanding its role in pathological processes. Biofilm formation was significant only in the hypervirulent ST-17 clone. Intraclonal spread of isolates indicates that a local lineage of isolates is responsible for infection by these bacteria.}, } @article {pmid33212951, year = {2020}, author = {Antar, A and Lee, MA and Yoo, Y and Cho, MH and Lee, SW}, title = {PXO_RS20535, Encoding a Novel Response Regulator, Is Required for Chemotactic Motility, Biofilm Formation, and Tolerance to Oxidative Stress in Xanthomonas oryzae pv. oryzae.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33212951}, issn = {2076-0817}, support = {2017R1A2B4004035//Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education/ ; }, abstract = {Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight of rice, possesses two-component regulatory systems (TCSs) as an intracellular signaling pathway. In this study, we observed changes in virulence, biofilm formation, motility, chemotaxis, and tolerance against oxidative stress of a knockout mutant strain for the PXO_RS20535 gene, encoding an orphan response regulator (RR). The mutant strain lost virulence, produced significantly less biofilm, and showed remarkably reduced motility in swimming, swarming, and twitching. Furthermore, the mutant strain lost glucose-guided movement and showed clear diminution of growth and survival in the presence of H2O2. These results indicate that the RR protein encoded in the PXO_RS20535 gene (or a TCS mediated by the protein) is closely involved in regulation of biofilm formation, all types of motility, chemotaxis, and tolerance against reactive oxygen species (ROS) in Xoo. Moreover we found that the expression of most genes required for a type six secretion system (T6SS) was decreased in the mutant, suggesting that lack of the RR gene most likely leads to defect of T6SS in Xoo.}, } @article {pmid33212840, year = {2020}, author = {Shenkutie, AM and Yao, MZ and Siu, GK and Wong, BKC and Leung, PH}, title = {Biofilm-Induced Antibiotic Resistance in Clinical Acinetobacter baumannii Isolates.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33212840}, issn = {2079-6382}, support = {PH16-01625//The Hong Kong PhD Fellowship Scheme/ ; }, abstract = {In order to understand the role of biofilm in the emergence of antibiotic resistance, a total of 104 clinical Acinetobacter baumannii strains were investigated for their biofilm-forming capacities and genes associated with biofilm formation. Selected biofilm-formers were tested for antibiotic susceptibilities when grown in biofilm phase. Reversibility of antibiotic susceptibility in planktonic cells regrown from biofilm were investigated. We found 59.6% of the strains were biofilm-formers, among which, 66.1% were non-multidrug resistant (MDR) strains. Presence of virulence genes bap, csuE, and abaI was significantly associated with biofilm-forming capacities. When strains were grown in biofilm state, the minimum biofilm eradication concentrations were 44, 407, and 364 times higher than the minimum bactericidal concentrations (MBC) for colistin, ciprofloxacin, and imipenem, respectively. Persisters were detected after treating the biofilm at 32-256 times the MBC of planktonic cells. Reversibility test for antibiotic susceptibility showed that biofilm formation induced reversible antibiotic tolerance in the non-MDR strains but a higher level of irreversible resistance in the extensively drug-resistant (XDR) strain. In summary, we showed that the non-MDR strains were strong biofilm-formers. Presence of persisters in biofilm contributed to the reduced antibiotic susceptibilities. Biofilm-grown Acinetobacter baumannii has induced antibiotic tolerance in non-MDR strains and increased resistance levels in XDR strains. To address the regulatory mechanisms of biofilm-specific resistance, thorough investigations at genome and transcription levels are warranted.}, } @article {pmid33210919, year = {2020}, author = {Verhorstert, KWJ and Guler, Z and de Boer, L and Riool, M and Roovers, JWR and Zaat, SAJ}, title = {In Vitro Bacterial Adhesion and Biofilm Formation on Fully Absorbable Poly-4-hydroxybutyrate and Nonabsorbable Polypropylene Pelvic Floor Implants.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {48}, pages = {53646-53653}, pmid = {33210919}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/*chemistry ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Escherichia coli/drug effects/physiology ; Pelvic Floor ; Polyesters/*chemistry ; Polypropylenes/*chemistry ; *Prostheses and Implants ; Staphylococcus aureus/drug effects/physiology ; Wettability ; }, abstract = {Knitted polypropylene (PP) implants for the correction of pelvic organ prolapse have been associated with complications such as vaginal exposure, infection, and pain. Since certain complications may be linked to bacterial contamination and persistent inflammation, there is a rationale to develop a biocompatible implant that is less prone to bacterial adhesion and biofilm formation. Delayed absorbable materials could meet these requirements and poly-4-hydroxybutyrate (P4HB) might be such a new material for future pelvic floor implants. We studied in vitro bacterial adhesion and biofilm formation on P4HB in comparison to PP. We investigated the influence of both polymers using flat films and compared P4HB and PP implants with different knitting designs. P4HB flat films were demonstrated to be hydrophilic with significantly less Staphylococcus aureus and Escherichia coli cultured from P4HB films than from hydrophobic PP films after 24 h of incubation. On the implants, a higher number of E. coli were cultured after 1 h of incubation from the knitted P4HB implant with the highest density and smallest pore size, compared to other P4HB and PP implants. No differences were observed between the implants for E. coli at later time points or for S. aureus incubation. These results show that in flat films, the polymer influences biofilm formation, demonstrated by a reduced biofilm formation on P4HB compared with PP flat films. In addition, the knitting design may affect bacterial adhesion. Despite certain design and material characteristics that give the knitted P4HB implants a higher surface area, this did not result in more bacterial adhesion and biofilm formation overall. Collectively, these results warrant further (pre)clinical investigations of P4HB pelvic floor implants.}, } @article {pmid33208265, year = {2021}, author = {Boyd, JD and Stromberg, AJ and Miller, CS and Grady, ME}, title = {Biofilm and cell adhesion strength on dental implant surfaces via the laser spallation technique.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {37}, number = {1}, pages = {48-59}, pmid = {33208265}, issn = {1879-0097}, support = {P20 GM130456/GM/NIGMS NIH HHS/United States ; P30 GM110788/GM/NIGMS NIH HHS/United States ; R03 DE029547/DE/NIDCR NIH HHS/United States ; UL1 TR001998/TR/NCATS NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Biofilms ; Cell Adhesion ; *Dental Implants ; Surface Properties ; Titanium ; }, abstract = {OBJECTIVE: The aims of this study are to quantify the adhesion strength differential between an oral bacterial biofilm and an osteoblast-like cell monolayer to a dental implant-simulant surface and develop a metric that quantifies the biocompatible effect of implant surfaces on bacterial and cell adhesion.

METHODS: High-amplitude short-duration stress waves generated by laser pulse absorption are used to spall bacteria and cells from titanium substrates. By carefully controlling laser fluence and calibration of laser fluence with applied stress, the adhesion difference between Streptococcus mutans biofilms and MG 63 osteoblast-like cell monolayers on smooth and rough titanium substrates is obtained. The ratio of cell adhesion strength to biofilm adhesion strength (i.e., Adhesion Index) is determined as a nondimensionalized parameter for biocompatibility assessment.

RESULTS: Adhesion strength of 143 MPa, with a 95% C.I. (114, 176), is measured for MG 63 cells on smooth titanium and 292 MPa, with a 95% C.I. (267, 306), on roughened titanium. Adhesion strength for S. mutans on smooth titanium is 320 MPa, with a 95% C.I. (304, 333), and remained relatively constant at 332 MPa, with a 95% C.I. (324, 343), on roughened titanium. The calculated Adhesion Index for smooth titanium is 0.451, with a 95% C.I. (0.267, 0.622), which increased to 0.876, with a 95% C.I. (0.780, 0.932), on roughened titanium.

SIGNIFICANCE: The laser spallation technique provides a platform to examine the tradeoffs of adhesion modulators on both biofilm and cell adhesion. This tradeoff is characterized by the Adhesion Index, which is proposed to aid biocompatibility screening and could help improve implantation outcomes. The Adhesion Index is implemented to determine surface factors that promote favorable adhesion of cells greater than biofilms. Here, an Adhesion Index ≫ 1 suggests favorable biocompatibility.}, } @article {pmid33207596, year = {2020}, author = {Pestana-Nobles, R and Leyva-Rojas, JA and Yosa, J}, title = {Searching Hit Potential Antimicrobials in Natural Compounds Space against Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {22}, pages = {}, pmid = {33207596}, issn = {1420-3049}, support = {"Convocatoria del Fondo de Ciencia, Tecnología e Innovación del Sistema General de Regalías para la conformación de una lista de proyectos elegibles para ser viabilizados, priorizados y aprobados por el OCAD en el marco del Programa de Becas de Excelencia//Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS)/ ; }, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Bacterial Proteins/chemistry ; Biofilms/drug effects/*growth & development ; Biological Products/*pharmacology ; Hydrogen Bonding ; Ligands ; Microbial Sensitivity Tests ; Molecular Dynamics Simulation ; Thermodynamics ; }, abstract = {Biofilms are communities of microorganisms that can colonize biotic and abiotic surfaces and thus play a significant role in the persistence of bacterial infection and resistance to antimicrobial. About 65% and 80% of microbial and chronic infections are associated with biofilm formation, respectively. The increase in infections by multi-resistant bacteria instigates the need for the discovery of novel natural-based drugs that act as inhibitory molecules. The inhibition of diguanylate cyclases (DGCs), the enzyme implicated in the synthesis of the second messenger, cyclic diguanylate (c-di-GMP), involved in the biofilm formation, represents a potential approach for preventing the biofilm development. It has been extensively studied using PleD protein as a model of DGC for in silico studies as virtual screening and as a model for in vitro studies in biofilms formation. This study aimed to search for natural products capable of inhibiting the Caulobacter crescentus enzyme PleD. For this purpose, 224,205 molecules from the natural products ZINC15 database, have been evaluated through molecular docking and molecular dynamic simulation. Our results suggest trans-Aconitic acid (TAA) as a possible starting point for hit-to-lead methodologies to obtain new inhibitors of the PleD protein and hence blocking the biofilm formation.}, } @article {pmid33207445, year = {2021}, author = {Yang, Y and Zhuang, H and Cui, H and Liu, B and Xie, G and Xing, D}, title = {Effect of waterproof breathable membrane based cathodes on performance and biofilm microbiomes in bioelectrochemical systems.}, journal = {The Science of the total environment}, volume = {753}, number = {}, pages = {142281}, doi = {10.1016/j.scitotenv.2020.142281}, pmid = {33207445}, issn = {1879-1026}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; }, abstract = {A novel method for fabricating air-cathodes was developed by assembling an activated carbon (AC) catalyst together with a waterproof breathable membrane (WBM) and stainless steel mesh (SSM) to reduce manufacturing costs of bioelectrochemical systems (BESs). WBMs made of different materials were tested in the assembly, including a hybrid of polypropylene and polyolefin (PPPO), polyethylene (PE), and polyurethane (PU), and compared against poly tetrafluoroethylene (PTFE)-based cathodes. Results showed that the maximum power density of the activated carbon-stainless steel mesh-polyurethane (AC@SSM/PU) assembly was 2.03 W/m[2] while that of conventional carbon cloth cathode assembly (Pt@CC/PTFE) was 1.51 W/m[2]. Compared to conventional cathode fabrication, AC@SSM/PU had a much lower cost and simpler manufacturing process. Illumina Miseq sequencing of 16S rRNA gene amplicons indicated that microbiomes were substantially different between anode and cathode biofilms. There was also a difference in the community composition between different cathode biofilms. The predominant population in the anode biofilms was Geobacter (38-75% relative abundance), while Thauera and Pseudomonas dominated the cathode biofilms. The results demonstrated that different types of air-cathodes influenced the microbial community assembly on the electrodes.}, } @article {pmid33206951, year = {2020}, author = {Jerdan, R and Cameron, S and Donaldson, E and Iungin, O and Moshynets, OV and Spiers, AJ}, title = {Community biofilm-formation, stratification and productivity in serially-transferred microcosms.}, journal = {FEMS microbiology letters}, volume = {367}, number = {24}, pages = {}, doi = {10.1093/femsle/fnaa187}, pmid = {33206951}, issn = {1574-6968}, mesh = {Bacteria/classification ; *Bacterial Physiological Phenomena ; Biodiversity ; *Biofilms/growth & development ; *Environmental Microbiology ; *Microbiological Techniques/methods ; }, abstract = {The establishment of O2 gradients in liquid columns by bacterial metabolic activity produces a spatially-structured environment. This produces a high-O2 region at the top that represents an un-occupied niche which could be colonised by biofilm-competent strains. We have used this to develop an experimental model system using soil-wash inocula and a serial-transfer approach to investigate changes in community-based biofilm-formation and productivity. This involved 10 transfers of mixed-community or biofilm-only samples over a total of 10-60 days incubation. In all final-transfer communities the ability to form biofilms was retained, though in longer incubations the build-up of toxic metabolites limited productivity. Measurements of microcosm productivity, biofilm-strength and attachment levels were used to assess community-aggregated traits which showed changes at both the community and individual-strain levels. Final-transfer communities were stratified with strains demonstrating a plastic phenotype when migrating between the high and low-O2 regions. The majority of community productivity came from the O2-depleted region rather than the top of the liquid column. This model system illustrates the complexity we expect to see in natural biofilm-forming communities. The connection between biofilms and the liquid column seen here has important implications for how these structures form and respond to selective pressure.}, } @article {pmid33206788, year = {2020}, author = {Bonete, JM and Silva, GD and Guidelli, ÉJ and GonÇalves, PJ and Almeida, LM and Baffa, O and Kinoshita, A}, title = {Tissue reaction and anti-biofilm action of new biomaterial composed of latex from Hancornia speciosa Gomes and silver nanoparticles.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {92}, number = {4}, pages = {e20191584}, doi = {10.1590/0001-3765202020191584}, pmid = {33206788}, issn = {1678-2690}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biocompatible Materials/pharmacology ; Biofilms ; *Latex ; *Metal Nanoparticles ; Rats ; Silver/pharmacology ; }, abstract = {In this work, the natural latex extracted from Harconia speciosa was incorporated with silver nanoparticles (AgNP) to compose a functional biomaterial associating the intrinsic angiogenic activity of the latex and the antimicrobial activity of AgNP. Tissue reaction after subcutaneous implantation in dorsum of rats of membranes without AgNP and with 0.05%, 0.4% AgNP was compared at 3, 7 and 25 days. No statistically significant difference in the tissue response of the different biomaterials was observed, indicating that AgNP did not interfere with the inflammatory reaction (p > 0.05) or with the angiogenic activity of latex. Biomembranes were also tested against bacterial biofilm formation by Staphylococcus aureus and the antimicrobial activity of the new biomaterial can be found with bacteria crenation (0.05% AgNP) and no biofilm deposition (0.4% AgNP). Therefore, this biomaterial has interesting properties for the tissue repair process and may be feasible for future applications as dressing.}, } @article {pmid33206627, year = {2020}, author = {McMahon, RE and Salamone, AB and Poleon, S and Bionda, N and Salamone, JC}, title = {Efficacy of Wound Cleansers on Wound-Specific Organisms Using In Vitro and Ex Vivo Biofilm Models.}, journal = {Wound management & prevention}, volume = {66}, number = {11}, pages = {31-42}, pmid = {33206627}, issn = {2640-5245}, mesh = {Animals ; Biguanides/standards/therapeutic use ; *Biofilms ; Detergents/standards/*therapeutic use ; Disease Models, Animal ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Silver/standards/therapeutic use ; Sodium Hypochlorite/standards/therapeutic use ; Swine/microbiology ; Wound Healing/*drug effects ; }, abstract = {UNLABELLED: Biofilms are believed to be a source of chronic inflammation in non-healing wounds.

PURPOSE: In this study, the pre-clinical anti-biofilm efficacy of several wound cleansers was examined using the Calgary minimum biofilm eradication concentration (MBEC) and ex vivo porcine dermal explant (PDE) models on Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans biofilms.

METHODS: A surfactant-based cleanser and antimicrobial-based cleansers containing ionic silver, hypochlorous acid (HOCl), sodium hypochlorite (NaOCl), and polyhexamethylene biguanide (PHMB) were tested on the MBEC model biofilms with a 10-minute application time. Select cleansers were then tested on the mature PDE biofilms with 10-minute applications followed by the application of cleanser-soaked gauze. The PDE model was further expanded to include single and daily applications of the cleansers to mimic daily and 72-hour dressing changes.

RESULTS: In the MBEC model, PHMB- and HOCl-based cleansers reduced immature MRSA, C albicans, and P aeruginosa biofilm regrowth by > 3× when compared with silver, surfactant, and saline cleansers. The major differences could be elucidated in the PDE model in which, after daily application, 1 PHMB-based cleanser showed a statistically significant reduction (3-8 CFU/mL log reduction) in all mature biofilms tested, while a NaOCl-based cleanser showed significant reduction in 2 microorganisms (3-5 CFU/mL log reduction, P aeruginosa and MRSA).The other PHMB-based cleanser showed a statistically significant 3 log CFU/mL reduction in P aeruginosa. The remaining cleansers showed no statistically significant difference from the saline control.

CONCLUSION: Results confirm that there are model-dependent differences in the outcomes of these studies, suggesting the importance of model selection for product screening. The results indicate that 1 PHMB-based cleanser was effective in reducing mature P aeruginosa, MRSA, and C albicans biofilms and that sustained antimicrobial presence was necessary to reduce or eliminate these mature biofilms.}, } @article {pmid33205550, year = {2021}, author = {Nadler, N and Kvich, L and Bjarnsholt, T and Jensen, JB and Gögenur, I and Azawi, N}, title = {The discovery of bacterial biofilm in patients with muscle invasive bladder cancer.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {129}, number = {5}, pages = {265-270}, doi = {10.1111/apm.13097}, pmid = {33205550}, issn = {1600-0463}, mesh = {Aged ; Aged, 80 and over ; Bacteria/*isolation & purification ; Biofilms/*growth & development ; Carcinoma, Squamous Cell/microbiology/pathology/surgery ; Cystoscopy ; Female ; Humans ; Male ; Muscle Neoplasms/*microbiology/pathology/surgery ; Neoplasm Invasiveness ; Urinary Bladder Neoplasms/*microbiology/pathology/surgery ; }, abstract = {The carcinogenic effects of microorganisms have been discovered in multiple cancer types. In urology, the development of squamous cell carcinoma of the bladder due to the parasitic infection with Schistosoma Mansoni is widely accepted. The oncogenic potential of biofilms has been studied in colorectal cancer and experimental studies have shown that bacteria such as Escherichia coli drive the development of colorectal cancer. Notably, Escherichia coli is responsible for 80% of all urinary tract infections. Recent findings suggest an altered urinary microbiome in patients with bladder cancer compared to healthy subjects. In this case series, we demonstrate our findings of biofilm formation in human bladder cancer tissue. Tissue samples from ten patients that underwent routine Transurethral Resection of Bladder Tumor (TURBT) were obtained from the Danish National Biobank. Pathological tissue was examined for presence of bacterial aggregates by Fluorescence in situ Hybridization. In two of ten patients, analysis showed abundant bacterial aggregation on the surface epithelium. Both positive cases had pT2 urothelial bladder cancer. Our findings suggest that biofilm occurs in urothelial cancer tissue indicating an association between biofilm formation and bladder cancer.}, } @article {pmid33205020, year = {2020}, author = {Cavitt, TB and Carlisle, JG and Dodds, AR and Faulkner, RA and Garfield, TC and Ghebranious, VN and Hendley, PR and Henry, EB and Holt, CJ and Lowe, JR and Lowry, JA and Oskin, DS and Patel, PR and Smith, D and Wei, W}, title = {Thermodynamic Surface Analyses to Inform Biofilm Resistance.}, journal = {iScience}, volume = {23}, number = {11}, pages = {101702}, pmid = {33205020}, issn = {2589-0042}, abstract = {Biofilms are the habitat of 95% of bacteria successfully protecting bacteria from many antibiotics. However, inhibiting biofilm formation is difficult in that it is a complex system involving the physical and chemical interaction of both substrate and bacteria. Focusing on the substrate surface and potential interactions with bacteria, we examined both physical and chemical properties of substrates coated with a series of phenyl acrylate monomer derivatives. Atomic force microscopy (AFM) showed smooth surfaces often approximating surgical grade steel. Induced biofilm growth of five separate bacteria on copolymer samples comprising varying concentrations of phenyl acrylate monomer derivatives evidenced differing degrees of biofilm resistance via optical microscopy. Using goniometric surface analyses, the van Oss-Chaudhury-Good equation was solved linear algebraically to determine the surface energy profile of each polymerized phenyl acrylate monomer derivative, two bacteria, and collagen. Based on the microscopy and surface energy profiles, a thermodynamic explanation for biofilm resistance is posited.}, } @article {pmid33203690, year = {2020}, author = {Selvaraj, A and Valliammai, A and Muthuramalingam, P and Sethupathy, S and Subramenium, GA and Ramesh, M and Pandian, SK}, title = {Proteomic and Systematic Functional Profiling Unveils Citral Targeting Antibiotic Resistance, Antioxidant Defense, and Biofilm-Associated Two-Component Systems of Acinetobacter baumannii To Encumber Biofilm and Virulence Traits.}, journal = {mSystems}, volume = {5}, number = {6}, pages = {}, pmid = {33203690}, issn = {2379-5077}, abstract = {Acinetobacter baumannii has been reported as a multidrug-resistant bacterium due to biofilms and antimicrobial resistance mechanisms. Hence, novel therapeutic strategies are necessary to overcome A. baumannii infections. This study revealed that citral at 200 μg/ml attenuated A. baumannii biofilms by up to 90% without affecting viability. Furthermore, microscopic analyses and in vitro assays confirmed the antibiofilm efficacy of citral. The global effect of citral on A. baumannii was evaluated by proteomic, transcriptional, and in silico approaches. Two-dimensional (2D) gel electrophoresis and matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) analyses were used to assess the effect of citral on the A. baumannii cellular proteome. Quantitative real-time PCR (qPCR) analysis was done to validate the proteomic data and identify the differentially expressed A. baumannii genes. Protein-protein interactions, gene enrichment, and comparative gene network analyses were performed to explore the interactions and functional attributes of differentially expressed proteins of A. baumannii Global omics-based analyses revealed that citral targeted various mechanisms such as biofilm formation, antibiotic resistance, antioxidant defense, iron acquisition, and type II and type IV secretion systems. The results of antioxidant analyses and antibiotic sensitivity, blood survival, lipase, and hemolysis assays validated the proteomic results. Cytotoxicity analysis showed a nontoxic effect of citral on peripheral blood mononuclear cells (PBMCs). Overall, the current study unveiled that citral has multitarget efficacy to inhibit the biofilm formation and virulence of A. baumannii IMPORTANCE Acinetobacter baumannii is a nosocomial-infection-causing bacterium and also possesses multidrug resistance to a wide range of conventional antibiotics. The biofilm-forming ability of A. baumannii plays a major role in its resistance and persistence. There is an alarming need for novel treatment strategies to control A. baumannii biofilm-associated issues. The present study demonstrated the strong antibiofilm and antivirulence efficacy of citral against A. baumannii In addition, proteomic analysis revealed the multitarget potential of citral against A. baumannii Furthermore, citral treatment enhances the susceptibility of A. baumannii to the host innate immune system and reactive oxygen species (ROS). Cytotoxicity analysis revealed the nonfatal effect of citral on human PBMCs. Therefore, citral could be the safest therapeutic compound and can be taken for further clinical evaluation for the treatment of biofilm-associated infections by A. baumannii.}, } @article {pmid33203672, year = {2020}, author = {Arjes, HA and Huang, KC}, title = {Straightening up for life in a biofilm.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {50}, pages = {31573-31574}, pmid = {33203672}, issn = {1091-6490}, support = {RM1 GM135102/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; Cell Shape ; Life Style ; *Vibrio cholerae ; }, } @article {pmid33202735, year = {2020}, author = {Cennamo, P and Ebbreo, M and Quarta, G and Trojsi, G and De Rosa, A and Carfagna, S and Caputo, P and Martelli Castaldi, M}, title = {UV-C Irradiation as a Tool to Reduce Biofilm Growth on Pompeii Wall Paintings.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {22}, pages = {}, pmid = {33202735}, issn = {1660-4601}, mesh = {*Biofilms/radiation effects ; Italy ; *Paintings ; Pigments, Biological/radiation effects ; *Ultraviolet Rays ; }, abstract = {This study focuses on the experimentation of a method based on the use of UV-C irradiation to eliminate the biofilms present in a tomb located in the necropolis of Porta Nocera, in Pompeii. For this study, the autotrophic component of the biofilm was isolated in the laboratory, while, contemporarily, the characterization of the composition of the pigments of the frescoes took place on original fragments, which had already detached from the tomb and were examined in situ. These preliminary analyses were necessary for the recreation of test samples in the laboratory, which closely matched the original surfaces. Artificial biofilms were used for experimental exposure to UV-C radiation. The exposure to UV-C radiation was carried out at different distances for a fixed time interval. The effectiveness of the biocidal action was assessed by employing optical microscopy techniques, through a careful visual assessment of the area occupied by the biofilm on the different test samples, using a photographic survey, as well as by means of colorimetric measurements using spectrometric techniques. In order to obtain an additional parameter to evaluate the death rate of microorganism cultures exposed to the UV-C radiation, the concentrations of the photosynthetic pigments were also measured by spectrophotometry. Results showed that biofilms were completely eradicated by radiation, and no change in pigment color was observed.}, } @article {pmid33202719, year = {2020}, author = {Arweiler, NB and Auschill, TM and Heumann, C and Hellwig, E and Al-Ahmad, A}, title = {Influence of Probiotics on the Salivary Microflora Oral Streptococci and Their Integration into Oral Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33202719}, issn = {2079-6382}, support = {AR 341/5-1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {Probiotics' ability to integrate into dental biofilms is not yet clarified. The aim of this trial was to detect probiotic bacteria from probiotic products in dental biofilm and saliva during and after intake. In this parallel, randomized clinical trial, 39 subjects wore customized appliances to build up intra-oral biofilms (72-h periods). The trial was divided into screening (S) to determine baseline biofilm flora, intervention (I), and wash out (WO). During I (28 days), subjects consumed a product containing (a) Enterococcus faecalis (b) Lactobacilluscasei, or (c) Lactobacillus rhamnosus GG. Probiotic bacteria and Streptococci spp. were detected in the biofilms and saliva of the 35 subjects that were included in the analysis. During I and WO, the ratio of probiotics in the biofilm was very low compared to total bacterial load, while saliva had slightly but not significantly higher values. No significant changes of probiotic bacteria (p > 0.05) were found at any visit during I or WO. The proportion of streptococci was significantly reduced (p < 0.05) during I and even lower in WO, compared to S. Probiotic bacteria could neither integrate nor persist in dental biofilm and saliva but did influence the growth of streptococci in biofilm and saliva.}, } @article {pmid33202690, year = {2020}, author = {Thappeta, KRV and Zhao, LN and Nge, CE and Crasta, S and Leong, CY and Ng, V and Kanagasundaram, Y and Fan, H and Ng, SB}, title = {In-Silico Identified New Natural Sortase A Inhibitors Disrupt S. aureus Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {21}, number = {22}, pages = {}, pmid = {33202690}, issn = {1422-0067}, support = {H16/99/b0/004//Biomedical Research Council (BMRC) Transition Fund of A*STAR, Singapore./ ; }, mesh = {A549 Cells ; *Aminoacyltransferases/antagonists & inhibitors/chemistry/metabolism ; *Anti-Bacterial Agents/chemistry/pharmacology ; *Bacterial Proteins/antagonists & inhibitors/chemistry/metabolism ; Biofilms/*drug effects/growth & development ; Computer Simulation ; *Cysteine Endopeptidases/chemistry/metabolism ; *Enzyme Inhibitors/chemistry/pharmacology ; Hep G2 Cells ; Humans ; Staphylococcus aureus/*physiology ; }, abstract = {Sortase A (SrtA) is a membrane-associated enzyme that anchors surface-exposed proteins to the cell wall envelope of Gram-positive bacteria such as Staphylococcus aureus. As SrtA is essential for Gram-positive bacterial pathogenesis but dispensable for microbial growth or viability, SrtA is considered a favorable target for the enhancement of novel anti-infective drugs that aim to interfere with key bacterial virulence mechanisms, such as biofilm formation, without developing drug resistance. Here, we used virtual screening to search an in-house natural compound library and identified two natural compounds, N1287 (Skyrin) and N2576 ((4,5-dichloro-1H-pyrrol-2-yl)-[2,4-dihydroxy-3-(4-methyl-pentyl)-phenyl]-methanone) that inhibited the enzymatic activity of SrtA. These compounds also significantly reduced the growth of S. aureus but possessed moderate mammalian toxicity. Furthermore, S. aureus strains treated with these compounds exhibited reduction in adherence to host fibrinogen, as well as biofilm formation. Hence, these compounds may represent an anti-infective therapy without the side effects of antibiotics.}, } @article {pmid33202277, year = {2021}, author = {Wang, B and Yao, Y and Wei, P and Song, C and Wan, S and Yang, S and Zhu, GM and Liu, HM}, title = {Housefly Phormicin inhibits Staphylococcus aureus and MRSA by disrupting biofilm formation and altering gene expression in vitro and in vivo.}, journal = {International journal of biological macromolecules}, volume = {167}, number = {}, pages = {1424-1434}, doi = {10.1016/j.ijbiomac.2020.11.096}, pmid = {33202277}, issn = {1879-0003}, mesh = {Aldehyde Oxidoreductases/metabolism ; Animals ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis/chemistry ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Body Weight ; Cell Survival/drug effects ; Disease Models, Animal ; Gene Expression Regulation, Bacterial/drug effects ; Houseflies/*chemistry ; Humans ; Larva/drug effects/growth & development/microbiology ; Male ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/metabolism/physiology ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; RNA, Bacterial/metabolism ; Sigma Factor/metabolism ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/drug effects/genetics/metabolism/physiology ; Vancomycin/pharmacology ; }, abstract = {The increasing drug resistance of pathogenic bacteria is a crisis that threatens public health. Antimicrobial peptides (AMPs) have been suggested to be potentially effective alternatives to solve this problem. Here, we tested housefly Phormicin-derived peptides for effects on Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) infections in vitro and in vivo. A decreased bacterial load of MRSA was observed in the mouse scald model after treatment with Phormicin and in the positive control group (vancomycin). A mouse scrape model indicated that Phormicin helps the host fight drug-resistant MRSA infections. The protective effect of Phormicin on MRSA was confirmed in the Hermetia illucens larvae model. Phormicin also disrupted the formation of S. aureus and MRSA biofilms. Furthermore, this effect coincided with the downregulation of biofilm formation-related gene expression (agrC, sigB, RNAIII, altA, rbf, hla, hld, geh and psmɑ). Notably, virulence genes and several regulatory factors were also altered by Phormicin treatment. Based on these findings, housefly Phormicin helps the host inhibit MRSA infection through effects on biofilm formation and related gene networks. Therefore, housefly Phormicin potential represents a candidate agent for clinical MRSA chemotherapy.}, } @article {pmid33202254, year = {2021}, author = {Munusamy, K and Loke, MF and Vadivelu, J and Tay, ST}, title = {LC-MS analysis reveals biological and metabolic processes essential for Candida albicans biofilm growth.}, journal = {Microbial pathogenesis}, volume = {152}, number = {}, pages = {104614}, doi = {10.1016/j.micpath.2020.104614}, pmid = {33202254}, issn = {1096-1208}, mesh = {Antifungal Agents ; Biofilms ; *Biological Phenomena ; *Candida albicans ; Chromatography, Liquid ; Humans ; Proteomics ; Tandem Mass Spectrometry ; }, abstract = {Candidiasis is the most common fungal infection associated with high morbidity and mortality among immunocompromised patients. The ability to form biofilm is essential for Candida albicans pathogenesis and drug resistance. In this study, the planktonic cell and biofilm proteomes of C. albicans SC5314 strain analyzed using Liquid Chromatography-Mass Spectrometry (LC-MS) were compared. In total, 280 and 449 proteins are annotated from the planktonic cell and biofilm proteomes, respectively. The biofilm proteome demonstrated significantly higher proportion of proteins associated with the endomembrane system, mitochondrion and cytoplasm than planktonic proteome. Among proteins detected, 143 and 207 biological processes are annotated, of which, 38 and 102 are specific to the planktonic cell and biofilm proteomes, respectively, while 105 are common biological processes. The specific biological processes of C. albicans planktonic cell proteome are associated with cell polarity, energy metabolism and nucleotide (purine) metabolism, oxido-reduction coenzyme metabolic process, monosaccharide and amino acid (methionine) biosynthesis, regulation of anatomical structure morphogenesis and cell cycling, and single organism reproduction. Meanwhile, regulation of cellular macromolecule biosynthesis and metabolism, transcription and gene expression are major biological processes specifically associated with C. albicans biofilm proteome. Biosynthesis of leucine, isoleucine, and thiocysteine are highlighted as planktonic-related pathways, whereas folate metabolism, fatty acid metabolism and biosynthesis of amino acids (lysine, serine and glycine) are highlighted as biofilm-related pathways. In summary, LC-MS-based proteomic analysis reveals different adaptative strategies of C. albicans via specific biological and metabolic processes for planktonic cell and biofilm lifestyles. The mass spectrometry data are available via ProteomeXchange with identifiers PXD007830 (for biofilm proteome) and PXD007831 (for planktonic cell proteome).}, } @article {pmid33198058, year = {2020}, author = {Doub, JB}, title = {Bacteriophage Therapy for Clinical Biofilm Infections: Parameters That Influence Treatment Protocols and Current Treatment Approaches.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33198058}, issn = {2079-6382}, abstract = {Biofilm infections are extremely difficult to treat, which is secondary to the inability of conventional antibiotics to eradicate biofilms. Consequently, current definitive treatment of biofilm infections requires complete removal of the infected hardware. This causes significant morbidity and mortality to patients and therefore novel therapeutics are needed to cure these infections without removal of the infected hardware. Bacteriophages have intrinsic properties that could be advantageous in the treatment of clinical biofilm infections, but limited knowledge is known about the proper use of bacteriophage therapy in vivo. Currently titers and duration of bacteriophage therapy are the main parameters that are evaluated when devising bacteriophage protocols. Herein, several other important parameters are discussed which if standardized could allow for more effective and reproducible treatment protocols to be formulated. In addition, these parameters are correlated with the current clinical approaches being evaluated in the treatment of clinical biofilm infections.}, } @article {pmid33197515, year = {2021}, author = {Afonso, TB and Simões, LC and Lima, N}, title = {Occurrence of filamentous fungi in drinking water: their role on fungal-bacterial biofilm formation.}, journal = {Research in microbiology}, volume = {172}, number = {1}, pages = {103791}, doi = {10.1016/j.resmic.2020.11.002}, pmid = {33197515}, issn = {1769-7123}, mesh = {Bacteria/growth & development/isolation & purification ; Biofilms/*growth & development ; Drinking Water/*microbiology ; Fungi/*growth & development/*isolation & purification ; Microbial Interactions/*physiology ; Water Microbiology ; }, abstract = {Water is indispensable to life and safe and accessible supply must be available to all. The presence of microorganisms is a threat to this commitment. Biofilms are the main reservoir of microorganisms inside water distribution systems and they are extremely ecologically diverse. Filamentous fungi and bacteria can coexist inside these systems forming inter-kingdom biofilms. This review has the goal of summarizing the most relevant and recent reports on the occurrence of filamentous fungi in water distribution systems along with the current knowledge and gaps about filamentous fungal biofilm formation. Special focus is given on fungal-bacterial interactions in water biofilms.}, } @article {pmid33195893, year = {2020}, author = {Mumtaz, S and Behera, S and Mukhopadhyay, K}, title = {Lipidated Short Analogue of α-Melanocyte Stimulating Hormone Exerts Bactericidal Activity against the Stationary Phase of Methicillin-Resistant Staphylococcus aureus and Inhibits Biofilm Formation.}, journal = {ACS omega}, volume = {5}, number = {44}, pages = {28425-28440}, pmid = {33195893}, issn = {2470-1343}, abstract = {Stationary phase Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has been widely associated with many persistent infections as well as biofilm-associated infections, which are challenging due to their increasing antibiotic resistance. α-Melanocyte stimulating hormone (α-MSH) is an antimicrobial peptide (AMP) with well-established potent activity against S. aureus , but little is known about its antimicrobial efficacy against the stationary phase of the bacteria. We investigated the in vitro activities of two palmitoylated analogues, Pal-α-MSH(6-13) and Pal-α-MSH(11-13), of the C-terminal fragments of α-MSH against biofilm-producing strains of methicillin-sensitive S. aureus (MSSA) and MRSA. While both the peptides demonstrated anti-staphylococcal efficacy, Pal-α-MSH(11-13) emerged as the most effective AMP as palmitoylation led to a remarkable enhancement in its activity against stationary phase bacteria. Similar to α-MSH, both the designed analogues were membrane-active and exhibited improved bacterial membrane depolarization and permeabilization, as further confirmed via electron microscopy studies. Of the two peptides, Pal-α-MSH(11-13) was able to retain its activity in the presence of standard microbiological media, which otherwise is a major limiting factor toward the therapeutic use of α-MSH-based peptides. More importantly, Pal-α-MSH(11-13) was also highly effective in inhibiting the formation of biofilms. Furthermore, it did not lead to resistance development in MRSA cells even upon 18 serial passages at sub-MIC concentrations. These observations support the potential use of Pal-α-MSH(11-13) in the treatment of planktonic as well as sessile S. aureus infections.}, } @article {pmid33195420, year = {2020}, author = {Shaker, B and Ahmad, S and Thai, TD and Eyun, SI and Na, D}, title = {Rational Drug Design for Pseudomonas aeruginosa PqsA Enzyme: An in silico Guided Study to Block Biofilm Formation.}, journal = {Frontiers in molecular biosciences}, volume = {7}, number = {}, pages = {577316}, pmid = {33195420}, issn = {2296-889X}, abstract = {Pseudomonas aeruginosa is an opportunistic gram-negative bacterium implicated in acute and chronic nosocomial infections and a leading cause of patient mortality. Such infections occur owing to biofilm formation that confers multidrug resistance and enhanced pathogenesis to the bacterium. In this study, we used a rational drug design strategy to inhibit the quorum signaling system of P. aeruginosa by designing potent inhibitory lead molecules against anthranilate-CoA ligase enzyme encoded by the pqsA gene. This enzyme produces autoinducers for cell-to-cell communication, which result in biofilm formation, and thus plays a pivotal role in the virulence of P. aeruginosa. A library of potential drug molecules was prepared by performing ligand-based screening using an available set of enzyme inhibitors. Subsequently, structure-based virtual screening was performed to identify compounds showing the best binding conformation with the target enzyme and forming a stable complex. The two hit compounds interact with the binding site of the enzyme through multiple short-range hydrophilic and hydrophobic interactions. Molecular dynamic simulation and MM-PBSA/GBSA results to calculate the affinity and stability of the hit compounds with the PqsA enzyme further confirmed their strong interactions. The hit compounds might be useful in tackling the resistant phenotypes of this pathogen.}, } @article {pmid33194439, year = {2020}, author = {Elamary, R and Salem, WM}, title = {Optimizing and purifying extracellular amylase from soil bacteria to inhibit clinical biofilm-forming bacteria.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e10288}, pmid = {33194439}, issn = {2167-8359}, abstract = {BACKGROUND: Bacterial biofilms have become a major threat to human health. The objective of this study was to isolate amylase-producing bacteria from soil to determine the overall inhibition of certain pathogenic bacterial biofilms.

METHODS: We used serial dilution and the streaking method to obtain a total of 75 positive amylase isolates. The starch-agar plate method was used to screen the amylolytic activities of these isolates, and we used morphological and biochemical methods to characterize the isolates. Optimal conditions for amylase production and purification using Sephadex G-200 and SDS-PAGE were monitored. We screened these isolates' antagonistic activities and the purified amylase against pathogenic and multi-drug-resistant human bacteria using the agar disk diffusion method. Some standard antibiotics were controlled according to their degree of sensitivity. Finally, we used spectrophotometric methods to screen the antibiofilm 24 and 48 h after application of filtering and purifying enzymes in order to determine its efficacy at human pathogenic bacteria.

RESULTS: The isolated Bacillus species were Bacillus megaterium (26.7%), Bacillus subtilis (16%), Bacillus cereus (13.3%), Bacillus thuringiesis (10.7%), Bacillus lentus (10.7%), Bacillus mycoides (5.3%), Bacillus alvei (5.3%), Bacillus polymyxa (4%), Bacillus circulans (4%), and Micrococcus roseus (4%). Interestingly, all isolates showed a high antagonism to target pathogens. B. alevi had the highest recorded activity (48 mm) and B. polymyxa had the lowest recorded activity (12 mm) against Staphylococcus aureus (MRSA) and Escherichia coli, respectively. On the other hand, we detected no antibacterial activity for purified amylase. The supernatant of the isolated amylase-producing bacteria and its purified amylase showed significant inhibition for biofilm: 93.7% and 78.8%, respectively. This suggests that supernatant and purified amylase may be effective for clinical and environmental biofilm control.

DISCUSSION: Our results showed that soil bacterial isolates such as Bacillus sp. supernatant and its purified amylase are good antibiofilm tools that can inhibit multidrug-resistant former strains. They could be beneficial for pharmaceutical use. While purified amylase was effective as an antibiofilm, the isolated supernatant showed better results.}, } @article {pmid33194115, year = {2020}, author = {Palka, L and Mazurek-Popczyk, J and Arkusz, K and Baldy-Chudzik, K}, title = {Susceptibility to biofilm formation on 3D-printed titanium fixation plates used in the mandible: a preliminary study.}, journal = {Journal of oral microbiology}, volume = {12}, number = {1}, pages = {1838164}, pmid = {33194115}, issn = {2000-2297}, abstract = {Background: In the oral and maxillofacial surgery, fixation plates are commonly used for the stabilization of bone fragments. Additive manufacturing has enabled us to design and create personalized fixation devices that would ideally fit any given fracture. Aim: The aim of the present preliminary study was to assess the susceptibility of 3D-printed titanium fixation plates to biofilm formation. Methods: Plates were manufactured using selective laser melting (SLM) from Ti-6Al-4 V. Reference strains of Streptococcus mutans, Staphyloccocus epidermidis, Staphylococcus aureus, Lactobacillus rhamnosus, and Candida albicans, were tested to evaluate the material's susceptibility to biofilm formation over 48 hours. Biofilm formations were quantified by a colorimetric method and colony-forming units (CFU) quantification. Scanning electron microscopy (SEM) visualized the structure of the biofilm. Results: Surface analysis revealed the average roughness of 102.75 nm and irregular topography of the tested plates. They were susceptible to biofilm formation by all tested strains. The average CFUs were as follows: S. mutans (11.91 x 10[7]) > S.epidermidis (4.45 x 10[7]) > S. aureus (2.3 x 10[7]) > C.albicans (1.22 x 10[7]) > L. rhamnosus (0.78 x 10[7]). Conclusions: The present preliminary study showed that rough surfaces of additively manufactured titanium plates are susceptible to microbial adhesion. The research should be continued in order to compare additively manufactured plates with other commercially available osteotomy plates. Therefore, we suggest caution when using this type of material.}, } @article {pmid33193267, year = {2020}, author = {Biot, FV and Bachert, BA and Mlynek, KD and Toothman, RG and Koroleva, GI and Lovett, SP and Klimko, CP and Palacios, GF and Cote, CK and Ladner, JT and Bozue, JA}, title = {Evolution of Antibiotic Resistance in Surrogates of Francisella tularensis (LVS and Francisella novicida): Effects on Biofilm Formation and Fitness.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {593542}, pmid = {33193267}, issn = {1664-302X}, abstract = {Francisella tularensis, the causative agent of tularemia, is capable of causing disease in a multitude of mammals and remains a formidable human pathogen due to a high morbidity, low infectious dose, lack of a FDA approved vaccine, and ease of aerosolization. For these reasons, there is concern over the use of F. tularensis as a biological weapon, and, therefore, it has been classified as a Tier 1 select agent. Fluoroquinolones and aminoglycosides often serve as the first line of defense for treatment of tularemia. However, high levels of resistance to these antibiotics has been observed in gram-negative bacteria in recent years, and naturally derived resistant Francisella strains have been described in the literature. The acquisition of antibiotic resistance, either natural or engineered, presents a challenge for the development of medical countermeasures. In this study, we generated a surrogate panel of antibiotic resistant F. novicida and Live Vaccine Strain (LVS) by selection in the presence of antibiotics and characterized their growth, biofilm capacity, and fitness. These experiments were carried out in an effort to (1) assess the fitness of resistant strains; and (2) identify new targets to investigate for the development of vaccines or therapeutics. All strains exhibited a high level of resistance to either ciprofloxacin or streptomycin, a fluoroquinolone and aminoglycoside, respectively. Whole genome sequencing of this panel revealed both on-pathway and off-pathway mutations, with more mutations arising in LVS. For F. novicida, we observed decreased biofilm formation for all ciprofloxacin resistant strains compared to wild-type, while streptomycin resistant isolates were unaffected in biofilm capacity. The fitness of representative antibiotic resistant strains was assessed in vitro in murine macrophage-like cell lines, and also in vivo in a murine model of pneumonic infection. These experiments revealed that mutations obtained by these methods led to nearly all ciprofloxacin resistant Francisella strains tested being completely attenuated while mild attenuation was observed in streptomycin resistant strains. This study is one of the few to examine the link between acquired antibiotic resistance and fitness in Francisella spp., as well as enable the discovery of new targets for medical countermeasure development.}, } @article {pmid33193241, year = {2020}, author = {Gao, H and Ma, L and Qin, Q and Qiu, Y and Zhang, J and Li, J and Lou, J and Diao, B and Zhao, H and Shi, Q and Zhang, Y and Kan, B}, title = {Fur Represses Vibrio cholerae Biofilm Formation via Direct Regulation of vieSAB, cdgD, vpsU, and vpsA-K Transcription.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {587159}, pmid = {33193241}, issn = {1664-302X}, abstract = {Attached Vibrio cholerae biofilms are essential for environmental persistence and infectivity. The vps loci (vpsU, vpsA-K, and vpsL-Q) are required for mature biofilm formation and are responsible for the synthesis of exopolysaccharide. Transcription of vps genes is activated by the signaling molecule bis-(3'-5')-cyclic di-GMP (c-di-GMP), whose metabolism is controlled by the proteins containing the GGDEF and/or EAL domains. The ferric uptake regulator (Fur) plays key roles in the transcription of many genes involved in iron metabolism and non-iron functions. However, roles for Fur in Vibrio biofilm production have not been documented. In this study, phenotypic assays demonstrated that Fur, independent of iron, decreases in vivo c-di-GMP levels and inhibits in vitro biofilm formation by Vibrio cholerae. The Fur box-like sequences were detected within the promoter-proximal DNA regions of vpsU, vpsA-K, vieSAB, and cdgD, suggesting that transcription of these genes may be under the direct control of Fur. Indeed, the results of luminescence, quantitative PCR (qPCR), electrophoretic mobility shift assay (EMSA), and DNase I footprinting assays demonstrated Fur to bind to the promoter-proximal DNA regions of vpsU, vpsA-K, and cdgD to repress their transcription. In contrast, Fur activates the transcription of vieSAB in a direct manner. The cdgD and vieSAB encode proteins with GGDEF and EAL domains, respectively. Thus, data presented here highlight a new physiological role for Fur wherein it acts as a repressor of V. cholerae biofilm formation mediated by decreasing the production of exopolysaccharide and the intracellular levels of c-di-GMP.}, } @article {pmid33193183, year = {2020}, author = {Hympanova, M and Terlep, S and Markova, A and Prchal, L and Dogsa, I and Pulkrabkova, L and Benkova, M and Marek, J and Stopar, D}, title = {The Antibacterial Effects of New N-Alkylpyridinium Salts on Planktonic and Biofilm Bacteria.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {573951}, pmid = {33193183}, issn = {1664-302X}, abstract = {An increasing microbial resistance to known antibiotics raises a demand for new antimicrobials. In this study the antimicrobial properties of a series of new N-Alkylpyridinium quaternary ammonium compounds (QACs) with varying alkyl chain lengths were evaluated for several nosocomial pathogens. The chemical identities of the new QACs were determined by NMR, LC-MS, and HRMS. All the planktonic bacteria tested were susceptible to the new QACs as evaluated by MIC and MBC assays. The antimicrobial effect was most pronounced against Staphylococcus aureus clinical isolates. Live/dead staining CLSM was used to test the effectiveness of the QACs in biofilms. The effectiveness was up to 10-fold lower than in the plankton. When QACs were used as irrigants in Er:YAG - SSP photoacoustic steaming, their effectiveness significantly increased. The combined use of irrigants and photoacoustic streaming increased biofilm removal from the surface and increased the killing rate of the cells remaining on the surface. This may allow for a shorter chemical exposure time and lower dosage of QACs used in applications. The results demonstrate that the new QACs have potential to be applied as antibacterial compounds effective against planktonic and biofilm bacteria as well as irrigants in removal of difficult-to-reach biofilms.}, } @article {pmid33193155, year = {2020}, author = {Mishra, R and Panda, AK and De Mandal, S and Shakeel, M and Bisht, SS and Khan, J}, title = {Natural Anti-biofilm Agents: Strategies to Control Biofilm-Forming Pathogens.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {566325}, pmid = {33193155}, issn = {1664-302X}, abstract = {Pathogenic microorganisms and their chronic pathogenicity are significant concerns in biomedical research. Biofilm-linked persistent infections are not easy to treat due to resident multidrug-resistant microbes. Low efficiency of various treatments and in vivo toxicity of available antibiotics drive the researchers toward the discovery of many effective natural anti-biofilm agents. Natural extracts and natural product-based anti-biofilm agents are more efficient than the chemically synthesized counterparts with lesser side effects. The present review primarily focuses on various natural anti-biofilm agents, i.e., phytochemicals, biosurfactants, antimicrobial peptides, and microbial enzymes along with their sources, mechanism of action via interfering in the quorum-sensing pathways, disruption of extracellular polymeric substance, adhesion mechanism, and their inhibitory concentrations existing in literature so far. This study provides a better understanding that a particular natural anti-biofilm molecule exhibits a different mode of actions and biofilm inhibitory activity against more than one pathogenic species. This information can be exploited further to improve the therapeutic strategy by a combination of more than one natural anti-biofilm compounds from diverse sources.}, } @article {pmid33192509, year = {2020}, author = {Kadam, S and Madhusoodhanan, V and Bandgar, A and Kaushik, KS}, title = {From Treatise to Test: Evaluating Traditional Remedies for Anti-Biofilm Potential.}, journal = {Frontiers in pharmacology}, volume = {11}, number = {}, pages = {566334}, pmid = {33192509}, issn = {1663-9812}, abstract = {Traditional plant-based remedies hold vast potential as novel antimicrobial agents, particularly for recalcitrant infection states such as biofilms. To explore their potential, it is important to bring these remedies out of historical treatises, and into present-day scientific evaluation. Using an example of Indian traditional medicine (Ayurveda), we present a perspective toward evaluating historical remedies for anti-biofilm potential. Across compendia, we identified three plant-based remedies (of Kalanchoe pinnata, Cynodon dactylon, and Ocimum tenuiflorum) recommended for wounds. The remedies were reconstituted in accordance with historical practices, and tested for their effects on biofilm formation and eradication assays of wound pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Based on our approach and the results obtained, we provide insights into the considerations and challenges related to identifying potential remedies in historical texts, and testing them in the laboratory with standard biofilm assays. We believe this will be relevant for future studies exploring anti-biofilm approaches at the interface of historical medicine and present-day scientific practices.}, } @article {pmid33191462, year = {2021}, author = {Katsipis, G and Tsalouxidou, V and Halevas, E and Geromichalou, E and Geromichalos, G and Pantazaki, AA}, title = {In vitro and in silico evaluation of the inhibitory effect of a curcumin-based oxovanadium (IV) complex on alkaline phosphatase activity and bacterial biofilm formation.}, journal = {Applied microbiology and biotechnology}, volume = {105}, number = {1}, pages = {147-168}, pmid = {33191462}, issn = {1432-0614}, mesh = {Alkaline Phosphatase ; Animals ; Biofilms ; Cattle ; Computer Simulation ; *Curcumin/pharmacology ; Escherichia coli ; *Staphylococcus aureus ; }, abstract = {The scientific interest in the development of novel metal-based compounds as inhibitors of bacterial biofilm-related infections and alkaline phosphatase (ALP) deregulating effects is continuous and rising. In the current study, a novel crystallographically defined heteroleptic V(IV)-curcumin-bipyridine (V-Cur) complex with proven bio-activity was studied as a potential inhibitor of ALP activity and bacterial biofilm. The inhibitory effect of V-Cur was evaluated on bovine ALP, with two different substrates: para-nitrophenyl phosphate (pNPP) and adenosine triphosphate (ATP). The obtained results suggested that V-Cur inhibited the ALP activity in a dose-dependent manner (IC50 = 26.91 ± 1.61 μM for ATP, IC50 = 2.42 ± 0.12 μM for pNPP) exhibiting a mixed/competitive type of inhibition with both substrates tested. The evaluation of the potential V-Cur inhibitory effect on bacterial biofilm formation was performed on Gram (+) bacteria Staphylococcus aureus (S. aureus) and Gram (-) Escherichia coli (E. coli) cultures, and it positively correlated with inhibition of bacterial ALP activity. In silico study proved the binding of V-Cur at eukaryotic and bacterial ALP, and its interaction with crucial amino acids of the active sites, verifying complex's inhibitory potential. The findings suggested a specific anti-biofilm activity of V-Cur, offering a further dimension in the importance of metal complexes, with naturally derived products as biological ligands, as therapeutic agents against bacterial infections and ALP-associated diseases. KEY POINTS: • V-Cur inhibits bovine and bacterial alkaline phosphatases and bacterial biofilm formation. • Alkaline phosphatase activity correlates with biofilm formation. • In silico studies prove binding of the complex on alkaline phosphatase.}, } @article {pmid33190591, year = {2020}, author = {Lin, D and Chen, K and Guo, J and Ye, L and Li, R and Chan, EWC and Chen, S}, title = {Contribution of biofilm formation genetic locus, pgaABCD, to antibiotic resistance development in gut microbiome.}, journal = {Gut microbes}, volume = {12}, number = {1}, pages = {1-12}, pmid = {33190591}, issn = {1949-0984}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/*genetics ; Biofilms/growth & development ; Ciprofloxacin/*pharmacology ; DNA Gyrase/genetics ; DNA-Binding Proteins/genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/*genetics/growth & development ; Escherichia coli Proteins/*genetics ; Gastrointestinal Microbiome/*drug effects ; Rats ; }, abstract = {The human gut microbiome is the presumed site in which the emergence and evolution of antibiotic-resistant organisms constantly take place. To delineate the genetic basis of resistance formation in gut microbiome strains, we investigated the changes in the subpopulation structure of Escherichia coli in rat intestine before and after antimicrobial treatment. We observed that antibiotic treatment was selected for an originally minor subpopulation E. coli carrying the biofilm-forming genetic locus pgaABCD and the toxin-antitoxin system HipAB. Such strains possessed dramatically enhanced ability to withstand the detrimental effects of antibiotics, becoming a dominant subspecies upon antibiotic treatment and eventually evolving into resistant mutants. In contrast, E. coli strains that did not carry pgaABCD and HipAB were eradicated upon antibiotic treatment. Our findings, therefore, suggested that genes encoding biofilm-forming ability played an important role in conferring specific gut E. coli strains the ability to evolve into resistant strains upon a prolonged antibiotic treatment, and that such strains may therefore be considered bacterial antibiotic resistance progenitor cells in the gut microbiome.}, } @article {pmid33189801, year = {2021}, author = {Yu, Z and Tao, S and Xu, HHK and Weir, MD and Fan, M and Liu, Y and Zhou, X and Liang, K and Li, J}, title = {Rechargeable adhesive with calcium phosphate nanoparticles inhibited long-term dentin demineralization in a biofilm-challenged environment.}, journal = {Journal of dentistry}, volume = {104}, number = {}, pages = {103529}, doi = {10.1016/j.jdent.2020.103529}, pmid = {33189801}, issn = {1879-176X}, mesh = {Anti-Bacterial Agents ; Biofilms ; Calcium Phosphates/pharmacology ; Dental Cements/pharmacology ; Dentin ; Humans ; Methacrylates ; *Nanoparticles ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVES: This study aims to investigate the long-term demineralization-inhibition capability of a rechargeable adhesive with nanoparticles of amorphous calcium phosphate (NACP) on dentin in a biofilm-challenged environment.

METHODS: The NACP adhesive was immersed in a pH 4 solution to exhaust calcium (Ca) and phosphate (P) ions and then recharged with Ca and P ions. Dentin samples were demineralized underStreptococcus mutans biofilms for 24 h and randomly divided into two groups: (1) dentin control, (2) dentin with recharged NACP adhesives. Each day, all the samples were immersed in brain heart infusion broth with 1% sucrose (BHIS) for 4 h, and then in artificial saliva (AS) for 20 h. This cycle was repeated for 10 days. The pH of BHIS, the Ca and P ions content of the BHIS and AS were measured daily. After 10 days, the lactic acid production and colony-forming units of the biofilms were tested. The changes of remineralization/demineralization were also analyzed.

RESULTS: Dentin in the control group showed further demineralization. The recharged NACP adhesive neutralized acids, increasing the pH to above 5, and released large amounts of Ca and P ions each day. The recharged NACP adhesive decreased the production of lactic acid (P < 0.05), inhibited dentin demineralization and sustained the dentin hardness in the biofilm-challenged environment, showing an excellent long-term demineralization-inhibition capability.

CONCLUSIONS: The NACP adhesive could continuously inhibit dentin demineralization in a biofilm-challenged environment by recharging with Ca and P ions.

SIGNIFICANCE: The rechargeable NACP adhesive could provide long-term dentin bond protection.}, } @article {pmid33189396, year = {2021}, author = {Manobala, T and Shukla, SK and Rao, TS and Kumar, MD}, title = {Kinetic modelling of the uranium biosorption by Deinococcus radiodurans biofilm.}, journal = {Chemosphere}, volume = {269}, number = {}, pages = {128722}, doi = {10.1016/j.chemosphere.2020.128722}, pmid = {33189396}, issn = {1879-1298}, mesh = {Adsorption ; Biofilms ; *Deinococcus ; Hydrogen-Ion Concentration ; Kinetics ; *Uranium/analysis ; }, abstract = {Increasing number of reports on uranium contamination in groundwater bodies is a growing concern. Deinococcus radiodurans biofilm-based U(VI) bioremediation has great potential to provide solution. This study focuses on the kinetic modelling of uranium biosorption by D. radiodurans biofilm biomass and identification of the functional groups involved in the sequestration process. The effect of temperature, pH and amount of biofilm dry mass were studied using two uranyl ion concentrations (100 and 1000 mg/L). D. radiodurans dry biomass showed good affinity for uranyl ion adsorption. The kinetic experiments revealed that the biosorption process was spontaneous and exothermic in nature. The modelling of kinetic adsorption data revealed that U(VI) sorption by D. radiodurans biofilm biomass follows a pseudo-second-order reaction. Mechanism of U(VI) sorption was suggested to follow an intra-particle diffusion model, which includes covalent bonding between U(VI) and functional groups present on the surface of biofilm biomass, and diffusional barrier acts as a rate limiting step. External mass transfer was the rate-limiting step as evident from Boyd and Elovich plot. Chemical modifications in surface functional groups of biofilm biomass, confirmed the involvement of carboxyl, phosphate, and hydroxyl groups in uranium binding as a significant loss in U(VI) sorption capacity was recorded in these chemically modified biomasses. XRD data indicated the formation of metal deposits, predominantly as uranyl phosphates.}, } @article {pmid33188577, year = {2021}, author = {Ušjak, D and Dinić, M and Novović, K and Ivković, B and Filipović, N and Stevanović, M and Milenković, MT}, title = {Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production, Adhesion and Surface Motility of Acinetobacter baumannii by Inhibiting ompA Gene Expression.}, journal = {Chemistry & biodiversity}, volume = {18}, number = {1}, pages = {e2000786}, doi = {10.1002/cbdv.202000786}, pmid = {33188577}, issn = {1612-1880}, mesh = {Acinetobacter baumannii/*physiology ; Acyl-Butyrolactones/metabolism ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Outer Membrane Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Chalcone/chemical synthesis/*chemistry/pharmacology ; Gene Expression/*drug effects ; RNA, Messenger/metabolism ; }, abstract = {An increasing lack of available therapeutic options against Acinetobacter baumannii urged researchers to seek alternative ways to fight this extremely resistant nosocomial pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm potential of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. Real-time PCR was used to evaluate mRNA expression of biofilm-associated virulence factor genes (ompA, bap, abaI) in treated A. baumannii strains. Also, we examined virulence properties related to the expression of these genes, such as fibronectin- and collagen-mediated adhesion, surface motility, and quorum-sensing activity. The results revealed that the expression of all tested genes is downregulated together with the reduction of adhesion and motility. The conclusion is that 2'-hydroxy-2-methoxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of ompA and bap genes, which is reflected in reduced biofilm formation, adhesion, and surface motility.}, } @article {pmid33188190, year = {2020}, author = {Boyeldieu, A and Ali Chaouche, A and Ba, M and Honoré, FA and Méjean, V and Jourlin-Castelli, C}, title = {The phosphorylated regulator of chemotaxis is crucial throughout biofilm biogenesis in Shewanella oneidensis.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {54}, pmid = {33188190}, issn = {2055-5008}, mesh = {Anabasine/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Chemotaxis ; Escherichia coli Proteins/metabolism ; Flagella/metabolism ; Gene Expression Regulation, Bacterial ; Methyl-Accepting Chemotaxis Proteins/genetics/*metabolism ; *Mutation ; Nicotine/metabolism ; Phosphorus-Oxygen Lyases/metabolism ; Phosphorylation ; Shewanella/*physiology ; }, abstract = {The core of the chemotaxis system of Shewanella oneidensis is made of the CheA3 kinase and the CheY3 regulator. When appropriated, CheA3 phosphorylates CheY3, which, in turn, binds to the rotor of the flagellum to modify the swimming direction. In this study, we showed that phosphorylated CheY3 (CheY3-P) also plays an essential role during biogenesis of the solid-surface-associated biofilm (SSA-biofilm). Indeed, in a ΔcheY3 strain, the formation of this biofilm is abolished. Using the phospho-mimetic CheY3D56E mutant, we showed that CheY-P is required throughout the biogenesis of the biofilm but CheY3 phosphorylation is independent of CheA3 during this process. We have recently found that CheY3 interacts with two diguanylate cyclases (DGCs) and with MxdA, the c-di-GMP effector, probably triggering exopolysaccharide synthesis by the Mxd machinery. Here, we discovered two additional DGCs involved in SSA-biofilm development and showed that one of them interacts with CheY3. We therefore propose that CheY3-P acts together with DGCs to control SSA-biofilm formation. Interestingly, two orthologous CheY regulators complement the biofilm defect of a ΔcheY3 strain, supporting the idea that biofilm formation could involve CheY regulators in other bacteria.}, } @article {pmid33188012, year = {2020}, author = {Tan, L and Fu, J and Feng, F and Liu, X and Cui, Z and Li, B and Han, Y and Zheng, Y and Yeung, KWK and Li, Z and Zhu, S and Liang, Y and Feng, X and Wang, X and Wu, S}, title = {Engineered probiotics biofilm enhances osseointegration via immunoregulation and anti-infection.}, journal = {Science advances}, volume = {6}, number = {46}, pages = {}, doi = {10.1126/sciadv.aba5723}, pmid = {33188012}, issn = {2375-2548}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Coated Materials, Biocompatible/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Osseointegration ; *Probiotics/pharmacology ; Surface Properties ; Titanium/pharmacology ; }, abstract = {Preventing multidrug-resistant bacteria-related infection and simultaneously improving osseointegration are in great demand for orthopedic implants. However, current strategies are still limited to a combination of non-U.S. Food and Drug Administration-approved antibacterial and osteogenic agents. Here, we develop a food-grade probiotic-modified implant to prevent methicillin-resistant Staphylococcus aureus (MRSA) infection and accelerate bone integration. Lactobacillus casei is cultured on the surface of alkali heat-treated titanium (Ti) substrates and inactivated by ultraviolet irradiation to avoid sepsis induced by viable bacteria. This inactivated L. casei biofilm shows excellent 99.98% antibacterial effectiveness against MRSA due to the production of lactic acid and bacteriocin. In addition, the polysaccharides in the L. casei biofilm stimulate macrophages to secrete abundant osteogenic cytokines such as oncostatin M and improve osseointegration of the Ti implant. Inactivated probiotics modification can be a promising strategy to endow implants with both excellent self-antibacterial activity and osteointegration ability.}, } @article {pmid33187998, year = {2021}, author = {Lefebvre, M and Razakandrainibe, R and Villena, I and Favennec, L and Costa, D}, title = {Cryptosporidium-Biofilm Interactions: a Review.}, journal = {Applied and environmental microbiology}, volume = {87}, number = {3}, pages = {}, pmid = {33187998}, issn = {1098-5336}, mesh = {*Biofilms ; *Cryptosporidium ; *Oocysts ; }, abstract = {Biofilms are increasingly implicated as playing a major role in waterborne cryptosporidiosis. This review aims to synthesize all currently available data on interactions between Cryptosporidium oocysts and biofilms. Initially described following a waterborne outbreak, the integration of Cryptosporidium oocysts in biofilm has been well demonstrated. Biofilms appear important in the dissemination/protection of oocysts in the environment. Consequently, it has been suggested that substrate-associated biofilms should be systematically considered in oocyst water quality assessment. The influence of physicochemical parameters has been studied on oocyst biofilm retention. Biofilm surface roughness, ionic concentration (especially Ca[2+]), laminar/turbulent flow, shear stress, and electrostatic repulsion forces appear important to consider regarding oocyst release from biofilm. However, data analysis carried out during this review also revealed important gaps in biological interactions within biofilms, offering many perspectives for future work.}, } @article {pmid33187450, year = {2020}, author = {Rodrigues, AC and Almeida, FA and André, C and Vanetti, MCD and Pinto, UM and Hassimotto, NMA and Vieira, ÉNR and Andrade, NJ}, title = {Phenolic extract of Eugenia uniflora L. and furanone reduce biofilm formation by Serratia liquefaciens and increase its susceptibility to antimicrobials.}, journal = {Biofouling}, volume = {36}, number = {9}, pages = {1031-1048}, doi = {10.1080/08927014.2020.1844881}, pmid = {33187450}, issn = {1029-2454}, mesh = {Anti-Infective Agents ; *Biofilms ; *Eugenia ; Plant Extracts/pharmacology ; *Serratia liquefaciens ; }, abstract = {Serratia liquefaciens is a spoilage microorganism of relevance in the dairy industry because it is psychrotrophic, able to form biofilm, and produces thermoresistant proteases and lipases. Phenolic compounds and furanones have been studied as inhibitors of biofilm formation. In this study, the potential of the pulp phenolic extract of Eugenia uniflora L. orange fruits, also called pitanga, and furanone C30 on the inhibition of biofilm formation by S. liquefaciens L53 and the susceptibility to different antimicrobials were evaluated. The pulp phenolic extract of pitanga had a high total phenolic content, being mainly composed of glycosylated quercetins and ellagitannins. Sub-inhibitory concentrations of this extract and furanone reduced biofilm formation by S. liquefaciens on polystyrene and the amount of polysaccharides, proteins and extracellular DNA in the biofilms. These biofilms were also more susceptible to kanamycin. The combinations of furanone with phenolic extract of pitanga or kanamycin showed a synergistic effect with total growth inhibition of S. liquefaciens.}, } @article {pmid33186743, year = {2021}, author = {Bohl, LP and Isaac, P and Breser, ML and Orellano, MS and Correa, SG and Tolosa de Talamoni, NG and Porporatto, C}, title = {Interaction between bovine mammary epithelial cells and planktonic or biofilm Staphylococcus aureus: The bacterial lifestyle determines its internalization ability and the pathogen recognition.}, journal = {Microbial pathogenesis}, volume = {152}, number = {}, pages = {104604}, doi = {10.1016/j.micpath.2020.104604}, pmid = {33186743}, issn = {1096-1208}, mesh = {Animals ; Biofilms ; Cattle ; Epithelial Cells ; Female ; Life Style ; *Mastitis, Bovine ; Plankton ; *Staphylococcal Infections/veterinary ; Staphylococcus aureus ; }, abstract = {The main cause of mastitis, one of the most costly diseases in the dairy industry, is bacterial intramammary infection. Many of these bacteria are biofilm formers. Biofilms have been associated with resistance to antibiotics and to the host immune system. Here, we evaluated different experimental models representing bacterial biofilm lifestyle with the aim to study bacterial invasion into bovine mammary epithelial cells and the interaction of these cells with planktonic or biofilm Staphylococcus aureus. Staphylococcus aureus V329, its nonbiofilm-forming mutant and bovine mammary alveolar cells (MAC-T) were used. Bacterial invasion was studied using the gentamicin exclusion test, cell viability by trypan blue exclusion technique, TLR2 expression by flow cytometry, IL1β/IL6 production by ELISA and IL8/TNFα gene expression by real-time polymerase chain reaction. Biofilm and planktonic S. aureus showed differences in their invasion ability, with the biofilm mode showing a lower ability. Planktonic S. aureus reduced MAC-T viability after 6 h of co-culture, while biofilms did so at 24 h. MAC-T infected with planktonic bacteria showed increased TLR2 expression. Both lifestyles increased IL8 expression and IL1β/IL6 production but did not modify TNFα expression. Our results demonstrate that the bacterial lifestyle affects the invasion behavior, suggesting that biofilms reduce the bacteria-epithelial cell interaction. Planktonic cultures seem to induce higher cellular activation than biofilms. Further knowledge about the complex host-biofilm interaction is necessary to design more efficient therapies against bovine mastitis.}, } @article {pmid33185947, year = {2021}, author = {Lei, L and Zeng, J and Wang, L and Gong, T and Zheng, X and Qiu, W and Zhang, R and Yun, L and Yang, Y and Li, Y}, title = {Quantitative acetylome analysis reveals involvement of glucosyltransferase acetylation in Streptococcus mutans biofilm formation.}, journal = {Environmental microbiology reports}, volume = {13}, number = {2}, pages = {86-97}, doi = {10.1111/1758-2229.12907}, pmid = {33185947}, issn = {1758-2229}, mesh = {Acetylation ; Biofilms ; Glucosyltransferases/genetics ; *Protein Processing, Post-Translational ; *Streptococcus mutans ; }, abstract = {Streptococcus mutans (S. mutans) effectively utilizes dietary sucrose for the exopolysaccharide productions, which are mostly synthesized by the effects of glucosyltransferases (Gtfs). In the present study, the acetylome of S. mutans was identified and quantitative acetylome analysis of the bacterial biofilm growth (SMB) was compared with that of planktonic growth (SMP). The dynamic changes of protein acetylation were quantified using the integrated approach involving TMT labeling and Kac affinity enrichment followed by high-resolution mass spectrometry-based quantitative proteomics. In total, 973 acetylation sites in 445 proteins were identified, among which 617 acetylation sites in 302 proteins were quantitated. The overall analysis indicated that 22.7% of proteins were acetylated. Among the quantified proteins in SMB, the acetylation degree of lysine in 56 sites increased, while that of lysine decreased in 52 sites. In the acetylome of S. mutans, six significantly enriched motifs were identified and obtained including Kac****K, KacF, Kac****R, KacY, KacH, F*Kac. In addition, KEGG pathway-based enrichment analysis indicated significant enrichments in glycolysis/gluconeogenesis, and RNA degradation. Particularly, most downregulated acetylated lysine proteins were glucosyltransferase-SI, glucosyltransferase-I, and glucosyltransferase-S in S. mutans biofilm, which probably reveals a switch-off mechanism for the regulation of glucosyltransferases function during the biofilm development.}, } @article {pmid33182533, year = {2020}, author = {Oliveira, VC and Souza, MT and Zanotto, ED and Watanabe, E and Coraça-Huber, D}, title = {Biofilm Formation and Expression of Virulence Genes of Microorganisms Grown in Contact with a New Bioactive Glass.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33182533}, issn = {2076-0817}, support = {2018/17073‒4 and 2013/07793‒6//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {Bioactive glass F18 (BGF18), a glass containing SiO2-Na2O-K2O-MgO-CaO-P2O5, is highly effective as an osseointegration buster agent when applied as a coating in titanium implants. Biocompatibility tests using this biomaterial exhibited positive results; however, its antimicrobial activity is still under investigation. In this study we evaluated biofilm formation and expression of virulence-factor-related genes in Candida albicans, Staphylococcus epidermidis, and Pseudomonas aeruginosa grown on surfaces of titanium and titanium coated with BGF18. C. albicans, S. epidermidis, and P. aeruginosa biofilms were grown on specimens for 8, 24, and 48 h. After each interval, the pH was measured and the colony-forming units were counted for the biofilm recovery rates. In parallel, quantitative real-time polymerase chain reactions were carried out to verify the expression of virulence-factor-related genes. Our results showed that pH changes of the culture in contact with the bioactive glass were merely observed. Reduction in biofilm formation was not observed at any of the studied time. However, changes in the expression level of genes related to virulence factors were observed after 8 and 48 h of culture in BGF18. BGF18 coating did not have a clear inhibitory effect on biofilm growth but promoted the modulation of virulence factors.}, } @article {pmid33182261, year = {2020}, author = {Reigada, I and Guarch-Pérez, C and Patel, JZ and Riool, M and Savijoki, K and Yli-Kauhaluoma, J and Zaat, SAJ and Fallarero, A}, title = {Combined Effect of Naturally-Derived Biofilm Inhibitors and Differentiated HL-60 Cells in the Prevention of Staphylococcus aureus Biofilm Formation.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33182261}, issn = {2076-2607}, support = {722467//H2020 Marie Skłodowska-Curie Actions/ ; }, abstract = {Nosocomial diseases represent a huge health and economic burden. A significant portion is associated with the use of medical devices, with 80% of these infections being caused by a bacterial biofilm. The insertion of a foreign material usually elicits inflammation, which can result in hampered antimicrobial capacity of the host immunity due to the effort of immune cells being directed to degrade the material. The ineffective clearance by immune cells is a perfect opportunity for bacteria to attach and form a biofilm. In this study, we analyzed the antibiofilm capacity of three naturally derived biofilm inhibitors when combined with immune cells in order to assess their applicability in implantable titanium devices and low-density polyethylene (LDPE) endotracheal tubes. To this end, we used a system based on the coculture of HL-60 cells differentiated into polymorphonuclear leukocytes (PMNs) and Staphylococcus aureus (laboratory and clinical strains) on titanium, as well as LDPE surfaces. Out of the three inhibitors, the one coded DHA1 showed the highest potential to be incorporated into implantable devices, as it displayed a combined activity with the immune cells, preventing bacterial attachment on the titanium and LDPE. The other two inhibitors seemed to also be good candidates for incorporation into LDPE endotracheal tubes.}, } @article {pmid33181842, year = {2020}, author = {Cannon, ML and Merchant, M and Kabat, W and Catherine, L and White, K and Unruh, B and Ramones, A}, title = {In Vitro Studies of Xylitol and Erythritol Inhibition of Streptococcus Mutans and Streptococcus Sobrinus Growth and Biofilm Production.}, journal = {The Journal of clinical pediatric dentistry}, volume = {44}, number = {5}, pages = {307-314}, doi = {10.17796/1053-4625-44.5.4}, pmid = {33181842}, issn = {1053-4628}, mesh = {Biofilms ; Erythritol ; Humans ; *Streptococcus mutans ; *Streptococcus sobrinus ; Xylitol/pharmacology ; }, abstract = {The aim of this study was to evaluate synergy and inhibitory effects of xylitol and erythritol on Streptococcus mutans and Streptococcus sobrinus growth and biomass production on a polystyrene plastic surface. Study design; S. mutans and sobrinus strains (American Type Culture Collection reference strains 31341, 35668, 25175, sobrinus 33478) were cultivated in media (Todd Hewitt Broth with 1% sucrose or heart-brain infusion broth with 1% sucrose) at differing concentrations of xylitol or erythritol in microtiter assay plates incubated for 48 hours. Bacterial growth was quantified and measured by optical density using a microplate reader. Experiments assessing synergy and biofilm growth were carried out also using microdilution assays. All four strains were inhibited by 30% (w/v) xylitol, and 15% erythritol at 150mg/ml erythritol, 2/4 strains had reduced growth; at 270mg/ml, 4/4 strains were inhibited. Bactericidal effects were not observed at any polyol concentration. Combinations of both polyols in a checker board array were used to determine if there were any benefits of polyol combinations. Results The combination studies yielded mixed outcomes with indifference in growth for strains 68 and 78, potential additive effect for strain 75 and possible antagonism for strain 41. Assessment of biomass formation and polyol interference were also performed post MIC assessment. Strains 41, 68 and 75 produced significant biomass in the absence of either polyol. Both polyols inhibited biomass formation in a dose-dependent fashion. Strain 75 is a poor biomass producer and could not be assessed for polyol effects in our assay. Conclusion: Our results demonstrate significant polyol influence on the oral Streptococcal strains tested in our laboratory.}, } @article {pmid33181436, year = {2020}, author = {Yi, L and Li, J and Fan, Q and Mao, C and Jin, M and Liu, Y and Sun, L and Grenier, D and Wang, Y}, title = {The otc gene of Streptococcus suis plays an important role in biofilm formation, adhesion, and virulence in a murine model.}, journal = {Veterinary microbiology}, volume = {251}, number = {}, pages = {108925}, doi = {10.1016/j.vetmic.2020.108925}, pmid = {33181436}, issn = {1873-2542}, mesh = {Animals ; Bacterial Adhesion/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Disease Models, Animal ; Female ; Mice ; Mice, Inbred BALB C ; Ornithine Carbamoyltransferase/*genetics ; Specific Pathogen-Free Organisms ; Streptococcal Infections/*veterinary/virology ; Streptococcus suis/*genetics/*pathogenicity/physiology ; Swine ; Virulence ; Virulence Factors/*genetics ; }, abstract = {Streptococcus suis (S. suis) is an emerging zoonotic pathogen that can cause meningitis, arthritis, pneumonia, and sepsis. It poses a serious threat to the swine industry and public health worldwide. Ornithine carbamoyltransferase (OTC) is involved in the arginine deiminase system. OTC, which is a widely distributed enzyme in microorganisms, mammals, and higher plants, catalyzes the conversion of ornithine to citrulline. The present study showed that the otc gene plays an important role in the pathogenesis of S. suis infections. The ability of an otc-deficient mutant (Δotc) to form a biofilm was significantly reduced compared to the wild-type (WT) strain, as determined by crystal violet staining. Confocal laser scanning microscopy and scanning electron microscopy observations showed that the weakening of biofilm formation by the Δotc strain is related to a decrease in the extracellular matrix. In addition, compared to the WT strain, the Δotc strain had a reduced capacity to adhere to human laryngeal epidermoid carcinoma (HEp-2) cells compared to the WT strain. A real-time PCR analysis showed that the expression of adhesion-related genes by the Δotc strain was also lower than that of the WT strain. The virulence of the Δotc strain was significantly lower than that of the WT strain in a murine infection model. In addition, a histological analysis showed that the pathogenicity of the Δotc strain was lower than that of the WT strain, causing only slight inflammatory lesions in lung, liver, spleen, and kidney tissues. No significant differences were observed between the complemented mutant (CΔotc) and WT strains with respect to biofilm formation, adhesion, gene expression, and virulence. The present study provided evidence that the otc gene plays a pivotal role in the regulation of S. suis adhesion and biofilm formation. It also suggested that the otc gene is indirectly involved in the pathogenesis of S. suis serotype 2 infections.}, } @article {pmid33181276, year = {2021}, author = {Gao, R and van der Mei, HC and Ren, Y and Chen, H and Chen, G and Busscher, HJ and Peterson, BW}, title = {Thermo-resistance of ESKAPE-panel pathogens, eradication and growth prevention of an infectious biofilm by photothermal, polydopamine-nanoparticles in vitro.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {32}, number = {}, pages = {102324}, doi = {10.1016/j.nano.2020.102324}, pmid = {33181276}, issn = {1549-9642}, mesh = {Bacteria/*drug effects/*radiation effects ; Biofilms/*growth & development ; Indoles/*pharmacology ; *Infrared Rays ; Microbial Viability/drug effects/radiation effects ; Nanoparticles/*chemistry ; Polymers/*pharmacology ; Staphylococcus aureus/physiology ; *Temperature ; }, abstract = {Nanotechnology offers many novel infection-control strategies that may help prevent and treat antimicrobial-resistant bacterial infections. Here, we synthesized polydopamine, photothermal-nanoparticles (PDA-NPs) without further surface-functionalization to evaluate their potential with respect to biofilm-control. Most ESKAPE-panel pathogens in suspension with photothermal-nanoparticles showed three- to four-log-unit reductions upon Near-Infra-Red (NIR)-irradiation, but for enterococci only less than two-log unit reduction was observed. Exposure of existing Staphylococcus aureus biofilms to photothermal-nanoparticles followed by NIR-irradiation did not significantly kill biofilm-inhabitants. This indicates that the biofilm mode of growth poses a barrier to penetration of photothermal-nanoparticles, yielding dissipation of heat to the biofilm-surrounding rather than in its interior. Staphylococcal biofilm-growth in the presence of photothermal-nanoparticles could be significantly prevented after NIR-irradiation because PDA-NPs were incorporated in the biofilm and heat dissipated inside it. Thus, unmodified photothermal nanoparticles have potential for prophylactic infection-control, but data also constitute a warning for possible development of thermo-resistance in infectious pathogens.}, } @article {pmid33180031, year = {2021}, author = {Çimen, M and Düzgün, AÖ}, title = {Antibiotic induced biofilm formation of novel multidrug resistant Acinetobacter baumannii ST2121 clone.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {68}, number = {2}, pages = {80-86}, doi = {10.1556/030.2020.01240}, pmid = {33180031}, issn = {1588-2640}, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Clone Cells ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; beta-Lactamases/genetics ; }, abstract = {The aim of this study was to identify antimicrobial resistance and virulence factor genes exhibited by multidrug resistant (MDR) Acinetobacter baumannii, to analyze biofilm formation and to investigate clonal subtypes of isolate. Whole genome sequencing was done by Illumina NovaSeq 6,000 platform and multilocus sequence typing (MLST) was performed by Oxford and Pasteur typing schemes. Influence of imipenem and levofloxacin on biofilm formation was investigated in 96-well plates at 3 replicates. The strain was found to carry OXA-23, OXA-51-like, AmpC and TEM-1 beta-lactamases. The sequence of the blaOXA-51-like gene has been identified as a blaOXA-66. According to Pasteur MLST scheme the strain displayed ST2 allelic profile. However, based on Oxford MLST scheme this strain represents the new ST2121, as the gdhB gene has a single allelic mutation namely, the gdhB-227. It was determined that MDR isolate carried bap, basABCDFGHIJ, csuA/BABCDE, bauABCDEF, plcD, pgaABCD, entE, barAB, ompA, abaIR, piT2EAFTE/AUBl, fimADT, cvaC, bfmR, bfmS virulence genes. In our study imipenem induced the highest biofilm formation at a concentration of 32 µg/ml and levofloxacin at a concentration of 16 µg/ml. In conclusion, we detected a new MDR A. baumannii ST2121 clone harboring blaOXA-66 gene that has been reported for the first time in Turkey.}, } @article {pmid33178628, year = {2020}, author = {Gries, CM and Rivas, Z and Chen, J and Lo, DD}, title = {Intravital Multiphoton Examination of Implant-Associated Staphylococcus aureus Biofilm Infection.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {574092}, pmid = {33178628}, issn = {2235-2988}, support = {S10 OD020042/OD/NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Mice ; Prostheses and Implants ; *Staphylococcal Infections ; *Staphylococcus aureus ; }, abstract = {Bacterial infections associated with implanted medical devices represents a healthcare crisis due to their persistence, antibiotic tolerance, and immune avoidance. Indwelling devices are rapidly coated with host plasma and extracellular matrix proteins which can then be exploited by bacterial pathogens for adherence and subsequent biofilm development. Our understanding of the host-pathogen interface that determines the fate of biofilm-mediated infections is limited to the experimental models employed by laboratories studying these organisms. Current in vivo models of biofilm-mediated infection, while certainly useful, are typically limited to end-point analyses of bacterial burden enumeration, immune cell profiling, and cytokine/chemokine analysis. Thus, with these models, the complex, real-time assessment of biofilm development and innate immune cell activity remains imperceptible. Here, we describe a novel murine biofilm infection model employing time-lapse intravital multiphoton microscopy which permits concurrent and real-time visualization of Staphylococcus aureus biofilm formation and immune cell activity. Using cell tracking, we found that S. aureus biofilms impede neutrophil chemotaxis, redirecting their migration patterns to prevent biofilm invasion. This approach is the first to directly examine device-associated biofilm development and host-pathogen interactions and will serve to both further our understanding of infection development and help reveal the effects of future antibiofilm treatment strategies.}, } @article {pmid33178552, year = {2020}, author = {Horton, MV and Nett, JE}, title = {Candida auris infection and biofilm formation: going beyond the surface.}, journal = {Current clinical microbiology reports}, volume = {7}, number = {3}, pages = {51-56}, pmid = {33178552}, issn = {2196-5471}, support = {2017074/DDCF_/Doris Duke Charitable Foundation/United States ; R01 AI145939/AI/NIAID NIH HHS/United States ; }, abstract = {PURPOSE OF REVIEW: Emergent fungal pathogen C. auris is spreading in hospitals throughout the world and mortality rates for patients with invasive disease approach 60%. This species exhibits a heightened capacity to colonize skin, persist on hospital surfaces, rapidly disseminate in healthcare settings, and resist antifungal therapy.

RECENT FINDINGS: Current investigations show that C. auris produces biofilms, surface-adherent communities that resist antifungals and withstand desiccation. These biofilms form when C. auris is growing on skin or in conditions expected in the hospital environment and on implanted medical devices.

SUMMARY: Here we will highlight the topic of biofilm formation by C. auris. We illustrate how this process influences resistance to antimicrobials and promotes nosocomial transmission.}, } @article {pmid33178172, year = {2020}, author = {Zhou, L and Zhang, Y and Ge, Y and Zhu, X and Pan, J}, title = {Regulatory Mechanisms and Promising Applications of Quorum Sensing-Inhibiting Agents in Control of Bacterial Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {589640}, pmid = {33178172}, issn = {1664-302X}, abstract = {A biofilm is an assemblage of microbial cells attached to a surface and encapsulated in an extracellular polymeric substance (EPS) matrix. The formation of a biofilm is one of the important mechanisms of bacterial resistance, which not only leads to hard-to-control bacterial infections in humans and animals but also enables bacteria to be a major problem in various fields, such as food processing, wastewater treatment and metalworking. Quorum sensing (QS) is a bacterial cell-to-cell communication process that depends on the bacterial population density and is mediated by small diffusible signaling molecules called autoinducers (AIs). Bacteria use QS to regulate diverse arrays of functions, including virulence and biofilm formation. Therefore, the interference with QS by using QS inhibiting agents, including QS inhibitors (QSIs) and quorum quenching (QQ) enzymes, to reduce or even completely repress the biofilm formation of pathogenic bacteria appears to be a promising approach to control bacterial infections. In this review, we summarize the mechanisms of QS-regulating biofilm formation and QS-inhibiting agents that control bacterial biofilm formation, strategies for the discovery of new QS inhibiting agents, and the current applications of QS-inhibiting agents in several fields to provide insight into the development of effective drugs to control pathogenic bacteria.}, } @article {pmid33178146, year = {2020}, author = {Oliveira, LT and Medina-Alarcón, KP and Singulani, JL and Fregonezi, NF and Pires, RH and Arthur, RA and Fusco-Almeida, AM and Mendes Giannini, MJS}, title = {Dynamics of Mono- and Dual-Species Biofilm Formation and Interactions Between Paracoccidioides brasiliensis and Candida albicans.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {551256}, pmid = {33178146}, issn = {1664-302X}, abstract = {The oral cavity is a highly diverse microbial environment in which microorganisms interact with each other, growing as biofilms on biotic and abiotic surfaces. Understanding the interaction among oral microbiota counterparts is pivotal for clarifying the pathogenesis of oral diseases. Candida spp. is one of the most abundant fungi in the oral mycobiome with the ability to cause severe soft tissue lesions under certain conditions. Paracoccidioides spp., the causative agent of paracoccidioidomycosis, may also colonize the oral cavity leading to soft tissue damage. It was hypothesized that both fungi can interact with each other, increasing the growth of the biofilm and its virulence, which in turn can lead to a more aggressive infectivity. Therefore, this study aimed to evaluate the dynamics of mono- and dual-species biofilm growth of Paracoccidioides brasiliensis and Candida albicans and their infectivity using the Galleria mellonella model. Biomass and fungi metabolic activity were determined by the crystal violet and the tetrazolium salt reduction tests (XTT), respectively, and the colony-forming unit (CFU) was obtained by plating. Biofilm structure was characterized by both scanning electronic- and confocal laser scanning- microscopy techniques. Survival analysis of G. mellonella was evaluated to assess infectivity. Our results showed that dual-species biofilm with P. brasiliensis plus C. albicans presented a higher biomass, higher metabolic activity and CFU than their mono-species biofilms. Furthermore, G. mellonella larvae infected with P. brasiliensis plus C. albicans presented a decrease in the survival rate compared to those infected with P. brasiliensis or C. albicans, mainly in the form of biofilms. Our data indicate that P. brasiliensis and C. albicans co-existence is likely to occur on oral mucosal biofilms, as per in vitro and in vivo analysis. These data further widen the knowledge associated with the dynamics of fungal biofilm growth that can potentially lead to the discovery of new therapeutic strategies for these infections.}, } @article {pmid33176843, year = {2020}, author = {Sandbakken, ET and Witsø, E and Sporsheim, B and Egeberg, KW and Foss, OA and Hoang, L and Bjerkan, G and Løseth, K and Bergh, K}, title = {Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study.}, journal = {Journal of orthopaedic surgery and research}, volume = {15}, number = {1}, pages = {522}, pmid = {33176843}, issn = {1749-799X}, support = {P-101926-20//St. Olavs Hospital Universitetssykehuset i Trondheim/ ; }, mesh = {Biofilms/*growth & development ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Microscopy, Fluorescence ; Sonication/*methods ; Staphylococcus epidermidis/*physiology ; Time Factors ; }, abstract = {BACKGROUND: In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy.

METHODS: We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed.

RESULTS: Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner.

CONCLUSION: There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.}, } @article {pmid33176791, year = {2020}, author = {Straub, H and Eberl, L and Zinn, M and Rossi, RM and Maniura-Weber, K and Ren, Q}, title = {A microfluidic platform for in situ investigation of biofilm formation and its treatment under controlled conditions.}, journal = {Journal of nanobiotechnology}, volume = {18}, number = {1}, pages = {166}, pmid = {33176791}, issn = {1477-3155}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/drug effects/*growth & development ; Culture Media ; Escherichia coli ; Microfluidics/*methods ; }, abstract = {BACKGROUND: Studying bacterial adhesion and early biofilm development is crucial for understanding the physiology of sessile bacteria and forms the basis for the development of novel antimicrobial biomaterials. Microfluidics technologies can be applied in such studies since they permit dynamic real-time analysis and a more precise control of relevant parameters compared to traditional static and flow chamber assays. In this work, we aimed to establish a microfluidic platform that permits real-time observation of bacterial adhesion and biofilm formation under precisely controlled homogeneous laminar flow conditions.

RESULTS: Using Escherichia coli as the model bacterial strain, a microfluidic platform was developed to overcome several limitations of conventional microfluidics such as the lack of spatial control over bacterial colonization and allow label-free observation of bacterial proliferation at single-cell resolution. This platform was applied to demonstrate the influence of culture media on bacterial colonization and the consequent eradication of sessile bacteria by antibiotic. As expected, the nutrient-poor medium (modified M9 minimal medium) was found to promote bacterial adhesion and to enable a higher adhesion rate compared to the nutrient-rich medium (tryptic soy broth rich medium). However, in rich medium the adhered cells colonized the glass surface faster than those in poor medium under otherwise identical conditions. For the first time, this effect was demonstrated to be caused by a higher retention of newly generated bacteria in the rich medium, rather than faster growth especially during the initial adhesion phase. These results also indicate that higher adhesion rate does not necessarily lead to faster biofilm formation. Antibiotic treatment of sessile bacteria with colistin was further monitored by fluorescence microscopy at single-cell resolution, allowing in situ analysis of killing efficacy of antimicrobials.

CONCLUSION: The platform established here represents a powerful and versatile tool for studying environmental effects such as medium composition on bacterial adhesion and biofilm formation. Our microfluidic setup shows great potential for the in vitro assessment of new antimicrobials and antifouling agents under flow conditions.}, } @article {pmid33176181, year = {2021}, author = {Rocha, MP and Santos, MS and Rodrigues, PLF and Araújo, TSD and de Oliveira, JM and Rosa, LP and Bagnato, VS and da Silva, FC}, title = {Photodynamic therapry with curcumin in the reduction of enterococcus faecalis biofilm in bone cavity: rMicrobiological and spectral fluorescense analysis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {33}, number = {}, pages = {102084}, doi = {10.1016/j.pdpdt.2020.102084}, pmid = {33176181}, issn = {1873-1597}, mesh = {Animals ; Biofilms ; Cattle ; *Curcumin/pharmacology ; Enterococcus faecalis ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (PDT) has emerged as a therapeutic strategy to conventional procedures using antibiotics.

OBJECTIVE: To evaluate the antimicrobial effectiveness of PDT using blue light emitting diode (LED) associated with curcumin on biofilms of Enterococcus faecalis in bovine bone cavities and also to analyze the presence of these biofilms through spectral fluorescence.

MATERIALS AND METHODS: Standardized suspensions of E. faecalis (ATCC 29212) were incubated in artificial bone cavities for 14 days at 36 °C ± 1 °C for biofilm formation. The test specimens were distributed among the four experimental groups (n = 10): L-C- (control), L + C- (LED for 5 min), L-C+ (curcumin for 5 min) and L + C+ (PDT). Aliquots were collected from the bone cavities after treatments and seeded on BHI agar for 24 h at 36 °C ± 1 °C for CFU count. Before and after each treatment the specimens were submitted to spectral fluorescence, whose images were compared in the Image J program. The log10 CFU/mL results were submitted to the Kruskal-Wallis test (5%) and the biofilm fluorescence spectroscopy results were submitted to the Wilcoxon test (5%).

RESULTS: All treatments presented statistical difference when compared to the control, and PDT was responsible for the largest reduction (1.92 log10 CFU/mL). There was a reduction in the fluorescence emitted after the treatments, with greater statistical difference in the PDT group.

CONCLUSION: PDT was efficient in the reduction of E. faecalis biofilms. In all groups post treatment there was a significant reduction of biofilms in the fluorescence spectroscopy images with greater reduction in the PDT group.}, } @article {pmid33173002, year = {2020}, author = {Chen, Y and Le Mauff, F and Wang, Y and Lu, R and Sheppard, DC and Lu, L and Zhang, S}, title = {The Transcription Factor SomA Synchronously Regulates Biofilm Formation and Cell Wall Homeostasis in Aspergillus fumigatus.}, journal = {mBio}, volume = {11}, number = {6}, pages = {}, pmid = {33173002}, issn = {2150-7511}, support = {81361//CIHR/Canada ; 123306//CIHR/Canada ; FDN-159902//CIHR/Canada ; }, mesh = {Aspergillosis/microbiology ; Aspergillus fumigatus/genetics/growth & development/*metabolism ; *Biofilms ; Cell Wall/genetics/*metabolism ; Fungal Proteins/genetics/*metabolism ; Gene Expression Regulation, Fungal ; Glucose/metabolism ; Homeostasis ; Humans ; Polysaccharides/biosynthesis ; Promoter Regions, Genetic ; Transcription Factors/genetics/*metabolism ; }, abstract = {Polysaccharides are key components of both the fungal cell wall and biofilm matrix. Despite having distinct assembly and regulation pathways, matrix exopolysaccharide and cell wall polysaccharides share common substrates and intermediates in their biosynthetic pathways. It is not clear, however, if the biosynthetic pathways governing the production of these polysaccharides are cooperatively regulated. Here, we demonstrate that cell wall stress promotes production of the exopolysaccharide galactosaminogalactan (GAG)-depend biofilm formation in the major fungal pathogen of humans Aspergillus fumigatus and that the transcription factor SomA plays a crucial role in mediating this process. A core set of SomA target genes were identified by transcriptome sequencing and chromatin immunoprecipitation coupled to sequencing (ChIP-Seq). We identified a novel SomA-binding site in the promoter regions of GAG biosynthetic genes agd3 and ega3, as well as its regulators medA and stuA Strikingly, this SomA-binding site was also found in the upstream regions of genes encoding the cell wall stress sensors, chitin synthases, and β-1,3-glucan synthase. Thus, SomA plays a direct regulation of both GAG and cell wall polysaccharide biosynthesis. Consistent with these findings, SomA is required for the maintenance of normal cell wall architecture and compositions in addition to its function in biofilm development. Moreover, SomA was found to globally regulate glucose uptake and utilization, as well as amino sugar and nucleotide sugar metabolism, which provides precursors for polysaccharide synthesis. Collectively, our work provides insight into fungal adaptive mechanisms in response to cell wall stress where biofilm formation and cell wall homeostasis were synchronously regulated.IMPORTANCE The cell wall is essential for fungal viability and is absent from human hosts; thus, drugs disrupting cell wall biosynthesis have gained more attention. Caspofungin is a member of a new class of clinically approved echinocandin drugs to treat invasive aspergillosis by blocking β-1,3-glucan synthase, thus damaging the fungal cell wall. Here, we demonstrate that caspofungin and other cell wall stressors can induce galactosaminogalactan (GAG)-dependent biofilm formation in the human pathogen Aspergillus fumigatus We further identified SomA as a master transcription factor playing a dual role in both biofilm formation and cell wall homeostasis. SomA plays this dual role by direct binding to a conserved motif upstream of GAG biosynthetic genes and genes involved in cell wall stress sensors, chitin synthases, and β-1,3-glucan synthase. Collectively, these findings reveal a transcriptional control pathway that integrates biofilm formation and cell wall homeostasis and suggest SomA as an attractive target for antifungal drug development.}, } @article {pmid33172298, year = {2020}, author = {Dutta, K and Karmakar, A and Jana, D and Ballav, S and Shityakov, S and Panda, AK and Ghosh, C}, title = {Benzyl isocyanate isolated from the leaves of Psidium guajava inhibits Staphylococcus aureus biofilm formation.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {1000-1017}, doi = {10.1080/08927014.2020.1842877}, pmid = {33172298}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins ; Biofilms ; Isocyanates ; Molecular Docking Simulation ; Plant Leaves ; *Psidium ; *Staphylococcus aureus ; }, abstract = {Benzyl isocyanate (BIC), from methanol extract of Psidium guajava leaves, exhibited substantial anti-biofilm activities against Staphylococcus aureus, the common bacterial pathogen in nosocomial infections. Major components of the extract included eugenol, BIC, phenyl-2-methoxy-4-(1-propenyl)-acetate and 2,5-pyrrolidinedione,1-penta-3-4-dienyl, analyzed by GC-MS and HPLC studies. BIC exhibited substantial anti-biofilm activitiy against S. aureus, established by assaying biofilm formation, biofilm metabolic activity, bacterial adherence to hydrocarbons, exopolysaccharide formation, and optical and scanning electron microscopic studies. BIC significantly downregulated the important biofilm markers of S. aureus, viz., icaAD, sarA and agr, observed by quantitative real time polymerase chain reaction analysis. Molecular docking studies revealed thermodynamically favorable interaction of BIC with IcaA, SarA and Agr, having Gibbs energy values of -8.45, -9.09 and -10.29 kcal mol[-1], respectively. BIC after binding to IcaR, the repressor of IcaA, influences its binding to target DNA site (Eshape, -157.27 kcal mol[-1]). The results are considered to demonstrate anti-biofilm potential of BIC against bacterial infections.}, } @article {pmid33171909, year = {2020}, author = {Ben Abdallah, F and Lagha, R and Gaber, A}, title = {Biofilm Inhibition and Eradication Properties of Medicinal Plant Essential Oils against Methicillin-Resistant Staphylococcus aureus Clinical Isolates.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {13}, number = {11}, pages = {}, pmid = {33171909}, issn = {1424-8247}, support = {TURSP-2020/39//Taif University/ ; }, abstract = {Methicillin-resistant Staphylococcus aureus is a major human pathogen that poses a high risk to patients due to the development of biofilm. Biofilms, are complex biological systems difficult to treat by conventional antibiotic therapy, which contributes to >80% of humans infections. In this report, we examined the antibacterial activity of Origanum majorana, Rosmarinus officinalis, and Thymus zygis medicinal plant essential oils against MRSA clinical isolates using disc diffusion and MIC methods. Moreover, biofilm inhibition and eradication activities of oils were evaluated by crystal violet. Gas chromatography-mass spectrometry analysis revealed variations between oils in terms of component numbers in addition to their percentages. Antibacterial activity testing showed a strong effect of these oils against MRSA isolates, and T. zygis had the highest activity succeeded by O. majorana and R. officinalis. Investigated oils demonstrated high biofilm inhibition and eradication actions, with the percentage of inhibition ranging from 10.20 to 95.91%, and the percentage of eradication ranging from 12.65 to 98.01%. O. majorana oil had the highest biofilm inhibition and eradication activities. Accordingly, oils revealed powerful antibacterial and antibiofilm activities against MRSA isolates and could be a good alternative for antibiotics substitution.}, } @article {pmid33171584, year = {2020}, author = {Yuyama, KT and Rohde, M and Molinari, G and Stadler, M and Abraham, WR}, title = {Unsaturated Fatty Acids Control Biofilm Formation of Staphylococcus aureus and Other Gram-Positive Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33171584}, issn = {2079-6382}, support = {111//Deutscher Akademischer Austauschdienst/ ; 111//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)/ ; }, abstract = {Infections involving biofilms are difficult to treat due to increased resistances against antibiotics and the immune system. Hence, there is an urgent demand for novel drugs against biofilm infections. During our search for novel biofilm inhibitors from fungi, we isolated linoleic acid from the ascomycete Hypoxylon fragiforme which showed biofilm inhibition of several bacteria at sub-MIC concentrations. Many fatty acids possess antimicrobial activities, but their minimum inhibitory concentrations (MIC) are high and reports on biofilm interferences are scarce. We demonstrated that not only linoleic acid but several unsaturated long-chain fatty acids inhibited biofilms at sub-MIC concentrations. The antibiofilm activity exerted by long-chain fatty acids was mainly against Gram-positive bacteria, especially against Staphylococcus aureus. Micrographs of treated S. aureus biofilms revealed a reduction in the extracellular polymeric substances, pointing to a possible mode of action of fatty acids on S. aureus biofilms. The fatty acids had a strong species specificity. Poly-unsaturated fatty acids had higher activities than saturated ones, but no obvious rule could be found for the optimal length and desaturation for maximal activity. As free fatty acids are non-toxic and ubiquitous in food, they may offer a novel tool, especially in combination with antibiotics, for the control of biofilm infections.}, } @article {pmid33170767, year = {2021}, author = {Javed, S and Mirani, ZA and Pirzada, ZA}, title = {Phylogenetic Group B2 Expressed Significant Biofilm Formation among Drug Resistant Uropathogenic Escherichia coli.}, journal = {The Libyan journal of medicine}, volume = {16}, number = {1}, pages = {1845444}, pmid = {33170767}, issn = {1819-6357}, mesh = {Biofilms/*growth & development ; Drug Resistance, Bacterial/*genetics ; Escherichia coli Infections/*microbiology ; Humans ; Phylogeny ; Prospective Studies ; Urinary Tract Infections/*microbiology ; Uropathogenic Escherichia coli/genetics/*physiology ; }, abstract = {Biofilm is an important virulent marker attributed to the development of urinary tract infections (UTIs) by uropathogenic E. coli (UPEC). Drug-resistant and biofilm-producing UPEC are highly problematic causing catheter-associated or recurrent UTIs with significant morbidity and mortality. The aim of the current study was to investigate the prevalence of biofilm formation and phylogenetic groups in drug-resistant UPEC to predict their ability to cause disease. This prospective study was conducted at the Department of Microbiology, University of Karachi from January to June 2019. A total of 50 highly drug-resistant UPEC were selected for this study. UPEC isolates were screened to form biofilm by Congo-red agar (CRA) and microtiter plate (MTP) technique. The representative biofilm-producing isolates were analysed by scanning electron microscopy (SEM) monitoring. Phylogenetic analysis was done by PCR method based on two preserved genes; chuA, yjaA and TspE4-C2 DNA fragment. On CRA 34 (68%) UPEC were slime producers, while on MTP 20 (40%) were strong biofilm producers, 19 (38%) moderate and 11 (22%) were low to negligible biofilm producers. Molecular typing confirmed that phylogenetic group B2 was prevalent in drug resistant UPEC strains. Pathogenic strains belonged to phylogenetic group B2 and D were found to have greater biofilm forming ability as compare to non-pathogenic commensal strains that belonged to phylogenetic group A. Our results indicate that biofilm formation vary in drug resistant UPEC belonged to different phylogenetic groups. This study indicates possible link between in vitro biofilm formation and phylogenetic groups of UPEC, therefore this knowledge might be helpful to predict the pathogenic potential of UPEC and help design strategies for controlling UTIs.}, } @article {pmid33170120, year = {2021}, author = {Feng, M and Burgess, AC and Cuellar, RR and Schwab, NR and Balish, MF}, title = {Modelling persistent Mycoplasma pneumoniae biofilm infections in a submerged BEAS-2B bronchial epithelial tissue culture model.}, journal = {Journal of medical microbiology}, volume = {70}, number = {1}, pages = {}, doi = {10.1099/jmm.0.001266}, pmid = {33170120}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Bronchi/*microbiology/ultrastructure ; Cell Line ; Epithelial Cells/microbiology/ultrastructure ; Humans ; Microscopy, Electron, Scanning ; Mycoplasma pneumoniae/drug effects/genetics/*physiology/ultrastructure ; Pneumonia, Mycoplasma/*microbiology ; }, abstract = {Introduction. Infections with the respiratory pathogen Mycoplasma pneumoniae are often chronic, recurrent and resistant, persisting after antibiotic treatment. M. pneumoniae grown on glass forms protective biofilms, consistent with a role for biofilms in persistence. These biofilms consist of towers of bacteria interspersed with individual adherent cells.Hypothesis/Gap Statement. A tissue culture model for M. pneumoniae biofilms has not been described or evaluated to address whether growth, development and resistance properties are consistent with persistence in the host. Moreover, it is unclear whether the M. pneumoniae cells in the biofilm towers and individual bacterial cells have distinct roles in disease.Aim. We evaluated the properties of biofilms of M. pneumoniae grown on the immortalized human bronchial epithelial cell line BEAS-2B in relation to persistence in the host. We observed nucleation of biofilm towers and the disposition of individual cells in culture, leading to a model of how tower and individual cells contribute to infection and disease.Methodology. With submerged BEAS-2B cells as a substrate, we evaluated growth and development of M. pneumoniae biofilms using scanning electron microscopy and confocal laser scanning microscopy. We characterized resistance to erythromycin and complement using minimum inhibitory concentration assays and quantification of colony forming units. We monitored biofilm tower formation using time-lapse microscopic analysis of host-cell-free M. pneumoniae cultures.Results. Bacteria grown on host cells underwent similar development to those grown without host cells, including tower formation, rounding and incidence of individual cells outside towers. Erythromycin and complement significantly reduced growth of M. pneumoniae. Towers formed exclusively from pre-existing aggregates of bacteria. We discuss a model of the M. pneumoniae biofilm life cycle in which protective towers derive from pre-existing aggregates, and generate individual cytotoxic cells.Conclusion . M. pneumoniae can form protective biofilms in a tissue culture model, implicating biofilms in chronic infections, with aggregates of M. pneumoniae cells being important for establishing infections.}, } @article {pmid33168286, year = {2021}, author = {Sun, H and Liu, H and Zhang, M and Liu, Y}, title = {A novel single-stage ceramic membrane moving bed biofilm reactor coupled with reverse osmosis for reclamation of municipal wastewater to NEWater-like product water.}, journal = {Chemosphere}, volume = {268}, number = {}, pages = {128836}, doi = {10.1016/j.chemosphere.2020.128836}, pmid = {33168286}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors ; Ceramics ; Membranes, Artificial ; Osmosis ; Waste Disposal, Fluid ; *Wastewater/analysis ; Water ; *Water Purification ; }, abstract = {In this study, a single-stage ceramic membrane moving bed biofilm reactor (CMMBBR) was developed for simultaneous COD and nitrogen removal, while its effluent was further reclaimed to ultra-clean water by a coupled reverse osmosis (RO) unit. Results showed that approximately 97% of COD and 93% of total nitrogen (TN) removal were obtained in CMMBBR, with the effluent COD and TN concentrations being 8.15 mg/L and 2.31 mg/L, respectively. The excellent performance of CMMBBR was achieved at a constant permeate flux of 30 L/m[2]/h (LMH), with the average dTMP/dt of 0.05 bar/d due to the low suspended sludge concentration (i.e. 75 mg VSS/L) and the effective membrane scouring by fluidized biocarriers. The excellent permeate quality of CMMBBR could lead to a very low RO fouling rate of 0.029 bar/d, with the product water quality meeting typical NEWater standards in major ions concerned. In addition, the energy and cost analyses further indicated that the proposed CMMBBR-RO process could reduce 43.8% of energy consumption and 23.5% of operating cost compared to the current NEWater production process. It is expected that the integrated CMMBBR-RO process could provide a promising alternative for municipal wastewater reclamation to high-grade product water towards minimized sludge production and energy-efficient operation.}, } @article {pmid33168174, year = {2022}, author = {Simoneti, DM and Pereira-Cenci, T and Dos Santos, MBF}, title = {Comparison of material properties and biofilm formation in interim single crowns obtained by 3D printing and conventional methods.}, journal = {The Journal of prosthetic dentistry}, volume = {127}, number = {1}, pages = {168-172}, doi = {10.1016/j.prosdent.2020.06.026}, pmid = {33168174}, issn = {1097-6841}, mesh = {Biofilms ; *Composite Resins ; *Crowns ; Materials Testing ; Printing, Three-Dimensional ; Surface Properties ; }, abstract = {STATEMENT OF PROBLEM: Three-dimensionally printed interim restorations are among the recent technological advancements in dentistry. However, evidence of their performance is lacking.

PURPOSE: The purpose of this in vitro study was to compare the properties of interim restorations made by 3D printing with different technologies, laser stereolithography (SLA), technology and selective laser sintering (SLS) with those obtained by conventional techniques from acrylic resin and bis-acryl resin.

MATERIAL AND METHODS: Four different groups (acrylic resin, bis-acryl resin, SLS, SLA) were tested for flexural strength, Vickers microhardness, fatigue test, compressive strength, surface roughness before and after polishing, and biofilm formation. Specimens were made in the form of rectangular blocks, disks, and single crowns by following the manufacturing technique of each material. One-way ANOVA was used to test biofilm formation, Vickers microhardness, and the results of the 3-point bend flexural test, while the paired t test was used to assess differences in surface roughness between the materials (α=.05 for all tests).

RESULTS: The highest Vickers microhardness value was for acrylic resin interim crowns, while the elastic moduli were lower for both the 3D printed materials. Only the SLA resin fractured during the fatigue test. For surface roughness, a statistically significant difference was found among the studied materials (P<.001), with SLA resin and bis-acryl resin having the lowest values. No statistically significant differences were found for biofilm formation (P>.05).

CONCLUSIONS: SLS resin had favorable results for the Vickers microhardness, higher maximum flexural strength, and peak stress in load-to-fracture tests, the fatigue test, and biofilm formation compared with acrylic resin and bis-acryl resin, while SLA resin showed favorable results only for biofilm formation and surface roughness.}, } @article {pmid33166536, year = {2021}, author = {Goraj, W and Pytlak, A and Kowalska, B and Kowalski, D and Grządziel, J and Szafranek-Nakonieczna, A and Gałązka, A and Stępniewska, Z and Stępniewski, W}, title = {Influence of pipe material on biofilm microbial communities found in drinking water supply system.}, journal = {Environmental research}, volume = {196}, number = {}, pages = {110433}, doi = {10.1016/j.envres.2020.110433}, pmid = {33166536}, issn = {1096-0953}, mesh = {Biofilms ; *Drinking Water ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; Water Microbiology ; Water Supply ; }, abstract = {The biofilms and water samples from a model installation built of PVC-U, PE-HD and cast iron pipes were investigated using standard heterotrophic plate count and 16S rRNA Next Generation Sequencing. The results of the high throughput identification imply that the construction material strongly influences the microbiome composition. PVC-U and PE-HD pipes were dominated with Proteobacteria (54-60%) while the cast pipe was overgrown by Nitrospirae (64%). It was deduced that the plastic pipes create a more convenient environment for the potentially pathogenic taxa than the cast iron. The 7-year old biofilms were described as complex habitats with sharp oxidation-reduction gradients, where co-existence of methanogenic and methanotrophic microbiota takes place. Furthermore, it was found that the drinking water distribution systems (DWDS) are a useful tool for studying the ecology of rare bacterial phyla. New ecophysiological aspects were described for Aquihabitans, Thermogutta and Vampirovibrio. The discrepancy between identity of HPC-derived bacteria and NGS-revealed composition of biofilm and water microbiomes point to the need of introducing new diagnostical protocols to enable proper assessment of the drinking water safety, especially in DWDSs operating without disinfection.}, } @article {pmid33163963, year = {2020}, author = {Ampofo, EK and Amponsah, IK and Asante-Kwatia, E and Armah, FA and Atchoglo, PK and Mensah, AY}, title = {Indigenous Medicinal Plants as Biofilm Inhibitors for the Mitigation of Antimicrobial Resistance.}, journal = {Advances in pharmacological and pharmaceutical sciences}, volume = {2020}, number = {}, pages = {8821905}, pmid = {33163963}, issn = {2633-4690}, abstract = {The majority of indigenes in the rural areas of Ghana use herbal medicines for their primary health care. In this study, an ethnobotanical survey was undertaken to document medicinal plants used by traditional healers in the Ejisu-Juaben district in the Ashanti region of Ghana to treat infections and to further investigate the antibiofilm formation properties of selected plants in resisting pathogenic bacteria. Seventy medicinal plants used by traditional practitioners for the treatment of skin infections and wounds were documented from the ethnobotanical survey. Forty out of the seventy plants were collected and their methanol extracts evaluated for antimicrobial activity by the agar diffusion assay. Extracts that showed antibacterial activity were tested for biofilm inhibitory activity, and the most active plant was subsequently purified to obtain the active constituents. Biofilm formation was significantly mitigated by petroleum ether, ethyl acetate, and methanol extracts of Holarrhena floribunda stem bark. Bioassay-guided fractionation of an alkaloidal extract prepared from the methanol fraction led to the isolation of three steroidal alkaloids, namely, holonamine, holadienine, and conessine. The isolated compounds demonstrated varying degrees of biofilm formation inhibitory properties. The current study reveals that screening of indigenous medicinal plants could unravel potential leads to salvage the declining efficacy of conventional antibiotics. Holarrhena floribunda stem bark extract has strong biofilm formation inhibition properties, which could be attributed to the presence of steroidal alkaloids.}, } @article {pmid33163845, year = {2020}, author = {Ishikawa, T and Omori, T and Kikuchi, K}, title = {Bacterial biomechanics-From individual behaviors to biofilm and the gut flora.}, journal = {APL bioengineering}, volume = {4}, number = {4}, pages = {041504}, pmid = {33163845}, issn = {2473-2877}, abstract = {Bacteria inhabit a variety of locations and play important roles in the environment and health. Our understanding of bacterial biomechanics has improved markedly in the last decade and has revealed that biomechanics play a significant role in microbial biology. The obtained knowledge has enabled investigation of complex phenomena, such as biofilm formation and the dynamics of the gut flora. A bottom-up strategy, i.e., from the cellular to the macroscale, facilitates understanding of macroscopic bacterial phenomena. In this Review, we first cover the biomechanics of individual bacteria in the bulk liquid and on surfaces as the base of complex phenomena. The collective behaviors of bacteria in simple environments are next introduced. We then introduce recent advances in biofilm biomechanics, in which adhesion force and the flow environment play crucial roles. We also review transport phenomena in the intestine and the dynamics of the gut flora, focusing on that in zebrafish. Finally, we provide an overview of the future prospects for the field.}, } @article {pmid33163025, year = {2020}, author = {Kıvanç, M and Er, S}, title = {Biofilm formation of Candida Spp. isolated from the vagina and antibiofilm activities of lactic acid bacteria on the these Candida Isolates.}, journal = {African health sciences}, volume = {20}, number = {2}, pages = {641-648}, pmid = {33163025}, issn = {1729-0503}, mesh = {Biofilms/*growth & development ; Candida/classification/isolation & purification/*pathogenicity ; Candidiasis/*prevention & control ; Female ; Humans ; Lactobacillales/*physiology ; Lactobacillus acidophilus/*growth & development ; Vagina/*microbiology ; }, abstract = {BACKGROUND: In this study, it was aimed to investigate the effects of bacterial cells and cell-free filtrates of Lactobacillus acidophilus 8MR7 and Lactobacillus paracasei subspecies paracasei 10MR8 on the biofilm formation of 3 Candida tropicalis, 3 C. glabrata and 12 C. albicans isolated from the vagina and identified their virulence factors.

METHODS: Haemolytic activities esterase activities, and phospholipase activities as virulence factors of Candida strains were determined. Biofilm formations of these isolates were determined by Congo Red agar and microtitration plate method. Antibiofilm activities of bacterial cells and cell-free filtrates of L. acidophilus 8MR7 and L. paracasei subspecies paracasei 10MR8 on Candida isolates were determined by the microtitration plate method.

RESULT: Bacterial cells of L. acidophilus 8MR7 and L. paracasei subspecies paracasei 10MR8 were not very effective in the inhibition of biofilm, whereas it has been observed that the cell-free filtrates of these bacteria inhibit the formation of biofilms of Candida strains. Although the main mechanism for inhibiting the formation of Candida spp. biofilm is the competition for adhesion, it is concluded that the substances contained in the cell-free filtrates of lactic acid bacteria are also important.

CONCLUSION: These isolates promise hope as potential bacteria that can be used for anti-adhesion purposes in health-care materials.}, } @article {pmid33162949, year = {2020}, author = {Rembe, JD and Huelsboemer, L and Plattfaut, I and Besser, M and Stuermer, EK}, title = {Antimicrobial Hypochlorous Wound Irrigation Solutions Demonstrate Lower Anti-biofilm Efficacy Against Bacterial Biofilm in a Complex in-vitro Human Plasma Biofilm Model (hpBIOM) Than Common Wound Antimicrobials.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {564513}, pmid = {33162949}, issn = {1664-302X}, abstract = {Biofilms pose a relevant factor for wound healing impairment in chronic wounds. With 78% of all chronic wounds being affected by biofilms, research in this area is of high priority, especially since data for evidence-based selection of appropriate antimicrobials and antiseptics is scarce. Therefore, the objective of this study was to evaluate the anti-biofilm efficacy of commercially available hypochlorous wound irrigation solutions compared to established antimicrobials. Using an innovative complex in-vitro human plasma biofilm model (hpBIOM), quantitative reduction of Pseudomonas aeruginosa, Staphylococcus aureus, and Methicillin-resistant S. aureus (MRSA) biofilms by three hypochlorous irrigation solutions [two <0.08% and one 0.2% sodium hypochlorite (NaClO)] was compared to a 0.04% polyhexanide (PHMB) irrigation solution and 0.1% octenidine-dihydrochloride/phenoxyethanol (OCT/PE). Efficacy was compared to a non-challenged planktonic approach, as well as with increased substance volume over a prolonged exposure (up to 72 h). Qualitative visualization of biofilms was performed by scanning electron microscopy (SEM). Both reference agents (OCT/PE and PHMB) induced significant biofilm reductions within 72 h, whereby high volume OCT/PE even managed complete eradication of P. aeruginosa and MRSA biofilms after 72 h. The tested hypochlorous wound irrigation solutions achieved no relevant penetration and eradication of biofilms despite increased volume and exposure. Only 0.2% NaClO managed a low reduction under prolonged exposure. The results demonstrate that low-dosed hypochlorous wound irrigation solutions are significantly less effective than PHMB-based irrigation solution and OCT/PE, thus unsuitable for biofilm eradication on their own. The used complex hpBIOM thereby mimics the highly challenging clinical wound micro-environment, providing a more profound base for future clinical translation.}, } @article {pmid33161889, year = {2022}, author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA}, title = {Physicochemical methods for biofilm removal allow for control of biofilm retention time in a high rate MBBR.}, journal = {Environmental technology}, volume = {43}, number = {10}, pages = {1593-1602}, doi = {10.1080/09593330.2020.1843078}, pmid = {33161889}, issn = {1479-487X}, mesh = {*Biofilms ; Bioreactors ; Carbon ; Surface Properties ; *Waste Disposal, Fluid/methods ; Wastewater ; }, abstract = {Controlling biofilm retention time in moving bed biofilm reactor (MBBR) and maintaining its performance for A-stage carbon redirection requires a reliable method to use as side stream biocarriers treatment. This paper investigates biofilm detachment and residual biofilm activity under multiple physicochemical treatment scenarios aiming to provide an applicable technique for control of biofilm retention time. Different mixing intensities (i.e. 30-120 rpm), filling fractions (i.e. 20%-100%), and pH (i.e. 2-12) were evaluated. Two continuously operating MBBRs were subjected to pH shocks of 2 and 12 to evaluate the impact of residual acidic or alkaline compounds on performance. The highest solids detachment (i.e. 70 ± 5%) was found in alkaline conditions and independent of mixing intensity and filling fraction. Biofilm detachment test revealed that alkaline shock produced higher detachment levels in a longer exposure time when compared to acidic conditions. The kinetic tests revealed 60% and 90% of the residual biofilm activity was lost at pH 12 and 2. The continuously operating MBBRs subjected to pH shocks of 2 and 12 demonstrated a 50% loss of soluble COD removal capability within one hydraulic retention time. Extracellular polymeric substances changes in its structure and surface properties influencing the degree of biofilm detachment and its solubilization properties leading to differences in biofilm resilience. The findings have shown that by applying a side stream alkali treatment it could be possible to control biofilm retention time ensuring its detachment up to 70% and a reduced impact on the residual biofilm activity returning to the reactor.}, } @article {pmid33161361, year = {2021}, author = {Sui, M and Li, Y and Jiang, Y and Zhang, Y and Wang, L and Zhang, W and Wang, X}, title = {Light exposure interferes with electroactive biofilm enrichment and reduces extracellular electron transfer efficiency.}, journal = {Water research}, volume = {188}, number = {}, pages = {116512}, doi = {10.1016/j.watres.2020.116512}, pmid = {33161361}, issn = {1879-2448}, mesh = {Biofilms ; Electrodes ; *Electrons ; Extracellular Polymeric Substance Matrix ; *Geobacter ; }, abstract = {Light plays a vital role in shaping the structure of natural biofilms, but the effect of light on electroactive biofilm (EAB) has not been systematically studied. Herein, the influence of light on the formation of EAB was investigated. The EAB grown in darkness was more electroactive (EAB-0) with a peak current of ∼4.5 A/m[2], which was 196 and 5556 times higher than EABs formed under light intensities of 600 (EAB-600) and 1200 lux (EAB-1200). A thin EAB (30 μm) with spherical pink aggregates was obtained after 13 days in the darkness, comparing to a dense and flat biofilm grown under light conditions. Although the biomass in EAB-1200 (38.5 ± 1.6 mg/L) was 3 times larger than that in EAB-0 (11.4 ± 1.8 mg/L), the degradation of substrate was not sufficient. EAB-0 contained 85% Geobacter species, while the Rhodopseudomonas species made up 66% and 75% of EAB-600 and EAB-1200, respectively. The polysaccharides produced by EAB-1200 was 4801 ± 253 mg/m[2], which were 2.3 times higher than 2073 ± 160 mg/m[2] of EAB-0, resulting in lower electro-conductivity of the extracellular polymeric substances (EPS) under light conditions. Our findings confirmed that the light exposure affected EAB performance by altering the microbial components, electron transfer capacity, and biofilm morphology, which can be used in predictions of the formation and properties of engineered EAB in outdoor environments.}, } @article {pmid33160121, year = {2021}, author = {Bhardwaj, DK and Taneja, NK and Dp, S and Chakotiya, A and Patel, P and Taneja, P and Sachdev, D and Gupta, S and Sanal, MG}, title = {Phenotypic and genotypic characterization of biofilm forming, antimicrobial resistant, pathogenic Escherichia coli isolated from Indian dairy and meat products.}, journal = {International journal of food microbiology}, volume = {336}, number = {}, pages = {108899}, doi = {10.1016/j.ijfoodmicro.2020.108899}, pmid = {33160121}, issn = {1879-3460}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms ; Dairy Products/*microbiology ; Escherichia coli/*drug effects/*genetics/pathogenicity ; Food Safety ; Foodborne Diseases/microbiology ; Genotype ; Humans ; India ; Meat Products/*microbiology ; Phenotype ; Quorum Sensing ; Virulence/genetics ; }, abstract = {Escherichia coli are commensal gastrointestinal microflora of humans, but few strains may cause food-borne diseases. Present study aimed to identify antimicrobial resistant (AMR), biofilm-forming E. coli from Indian dairy and meat products. A total of 32 E. coli isolates were identified and evaluated for biofilm-formation. EMC17, an E. coli isolate was established as a powerful biofilm-former that attained maximum biofilm-formation within 96 h on glass and stainless-steel surfaces. Presence and expression of virulence-associated genes (adhesins, invasins and polysaccharides) and ability to adhere and invade human liver carcinoma HepG2 cell lines implicates EMC17 to be pathotype belonging to Extra-intestinal Pathogenic E. coli (ExPEC). Antibiotic profiling of EMC17 identified it as multi-drug resistant (MDR) strain, possessing extended spectrum β-lactamases (ESBL's) and biofilm phenotype. Early production of quorum sensing molecules (AHLs) alongside EPS production facilitated early onset of biofilm formation by EMC17. Furthermore, the biofilm-forming genes of EMC17 were significantly upregulated 3-27 folds in the biofilm-state. This study showed prevalence of MDR, biofilm-forming, pathogenic E. coli in Indian dairy and meat products that potentially serve as reservoirs for transmission of antimicrobial-resistant (AMR) genes of bacteria from food to humans and pose serious food safety threat.}, } @article {pmid33160113, year = {2021}, author = {Wang, N and Gao, J and Yuan, L and Jin, Y and He, G}, title = {Metabolomics profiling during biofilm development of Bacillus licheniformis isolated from milk powder.}, journal = {International journal of food microbiology}, volume = {337}, number = {}, pages = {108939}, doi = {10.1016/j.ijfoodmicro.2020.108939}, pmid = {33160113}, issn = {1879-3460}, mesh = {Animals ; Bacillus licheniformis/isolation & purification/*physiology ; Biofilms/growth & development ; *Dairying ; Metabolomics ; Milk/*microbiology ; Powders ; }, abstract = {Bacillus licheniformis is a major source of microbial contamination to dairy industry, and biofilm formation by this spoilage bacterium aggravates the safety issues. Especially for milk powder manufactures, the evaporation process at temperatures between 50 °C and 70 °C before spray drying, is a critical control point against thermophilic bacteria multiplication. In our study, metabolomics analysis was performed to investigate dynamic changes of the metabolites and their roles during process of biofilm development of B. licheniformis at 55 °C for 24 h. Amino acid metabolism was quite active, with cooperation from lipid metabolism, carbohydrate metabolism and nucleotide metabolism. Amino acid biosynthesis provided significant contributions especially during early biofilm development from 8 to 12 h. Metabolites involved in specific pathways of arginine biosynthetic, galactose metabolism and sphingolipid metabolism played a crucial role in building biofilm. This work provided new insights into dynamic metabolic alternations and a comprehensive network during B. licheniformis biofilm development, which will extend the knowledge on the metabolic process of biofilm formation by B. licheniformis. The results are helpful in creating better environmental hygiene in dairy processing and new strategies for ensuring quality of dairy products.}, } @article {pmid33158546, year = {2020}, author = {Gui, Y and Uroosa, and Bai, X and Wang, Z and Xu, G and Xu, H}, title = {An approach to assessing ecological quality status due to microalgae bloom using biofilm-dwelling protozoa based on biological trait analysis.}, journal = {Marine pollution bulletin}, volume = {161}, number = {Pt A}, pages = {111795}, doi = {10.1016/j.marpolbul.2020.111795}, pmid = {33158546}, issn = {1879-3363}, mesh = {Biofilms ; *Biological Products ; Environmental Monitoring ; *Microalgae ; Water Quality ; }, abstract = {Functional diversity/distinctness measure based trait has been proved to be a robust indicator to summarize the description of community structures and to assess water quality in different types of aquatic environment. In this study, for identifying the shielding effect of microalgae against protozoan grazing, a nine-day survey was conducted by exposing protozoan communities to a series of concentration gradients (10[0] (control), 10[4], 10[5], 10[6] and 10[7] cells ml[-1]) of two microalgae, respectively. Our results showed clear resistance of two test microalgae against protozoan grazing in five treatments. The functional distinctness measures commonly represented a decreasing trend along the gradient of concentrations of both microalgae. Ellipse tests based on the paired functional distinctness indices revealed that community functioning represented an uptrend departure from the expected pattern with the concentrations of both microalgae increase. Therefore, we suggest that the functional distinctness measures might be a reliable approach to detect the ecological effect of microalgae against protozoan grazing.}, } @article {pmid33158159, year = {2020}, author = {Stone, W and Tolmay, J and Tucker, K and Wolfaardt, GM}, title = {Disinfectant, Soap or Probiotic Cleaning? Surface Microbiome Diversity and Biofilm Competitive Exclusion.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33158159}, issn = {2076-2607}, support = {N/A//Claude Leon Foundation/ ; }, abstract = {This study extends probiotic cleaning research to a built environment. Through an eight-month cleaning trial, we compared the effect of three cleaning products (disinfectant, plain soap, and a probiotic cleaner containing a patented Bacillus spore consortium), and tap water as the control, on the resident microbiome of three common hospital surfaces (linoleum, ceramic, and stainless steel). Pathogens, Escherichia coli and Staphylococcus aureus, were deposited and desiccated, and competitive exclusion was assessed for each microbiome. Cell survival was shown to be an incomplete tool for measuring microbial competitive exclusion. Biofilm competition offered a fuller understanding of competitive dynamics. A test for culturable cell survival showed that both plain soap and probiotic cleaner regimes established a surface microbiome that outcompeted the two pathogens. A different picture emerged when observing biofilms with a deposited and desiccated GFP-labeled pathogen, Pseudomonas aeruginosa. Competitive exclusion was again demonstrated. On surfaces cleaned with disinfectant the pathogen outcompeted the microbiomes. On surfaces cleaned with plain soap, the microbiomes outcompeted the pathogen. However, on surfaces cleaned with probiotic cleaner, despite the exponentially higher surface microbial loads, the microbiome did not completely outcompete the pathogen. Thus, the standard culturable cell test for survival on a surface confirmed the competitive advantage that is typically reported for probiotic cleaners. However, observation of competition in biofilms showed that the more diverse microbiome (according to alpha and beta indices) established on a surface cleaned with plain soap had a better competitive advantage than the monoculture established by the probiotic cleaner. Therefore, microbial diversity appears to be as critical to the competitive exclusion principle as cell numbers. The study showed that both plain soap and probiotic cleaner fostered competitive exclusion far more effectively than disinfectant. Probiotic cleaners with microbial diversity could be worth considering for hospital cleaning.}, } @article {pmid33158121, year = {2020}, author = {Vyas, HKN and Indraratna, AD and Everest-Dass, A and Packer, NH and De Oliveira, DMP and Ranson, M and McArthur, JD and Sanderson-Smith, ML}, title = {Assessing the Role of Pharyngeal Cell Surface Glycans in Group A Streptococcus Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33158121}, issn = {2079-6382}, support = {APP1143266//National Health and Medical Research Council/ ; }, abstract = {Group A Streptococcus (GAS) causes 700 million infections and accounts for half a million deaths per year. Antibiotic treatment failure rates of 20-40% have been observed. The role host cell glycans play in GAS biofilm formation in the context of GAS pharyngitis and subsequent antibiotic treatment failure has not been previously investigated. GAS serotype M12 GAS biofilms were assessed for biofilm formation on Detroit 562 pharyngeal cell monolayers following enzymatic removal of all N-linked glycans from pharyngeal cells with PNGase F. Removal of N-linked glycans resulted in an increase in biofilm biomass compared to untreated controls. Further investigation into the removal of terminal mannose and sialic acid residues with α1-6 mannosidase and the broad specificity sialidase (Sialidase A) also found that biofilm biomass increased significantly when compared to untreated controls. Increases in biofilm biomass were associated with increased production of extracellular polymeric substances (EPS). Furthermore, it was found that M12 GAS biofilms grown on untreated pharyngeal monolayers exhibited a 2500-fold increase in penicillin tolerance compared to planktonic GAS. Pre-treatment of monolayers with exoglycosidases resulted in a further doubling of penicillin tolerance in resultant biofilms. Lastly, an additional eight GAS emm-types were assessed for biofilm formation in response to terminal mannose and sialic acid residue removal. As seen for M12, biofilm biomass on monolayers increased following removal of terminal mannose and sialic acid residues. Collectively, these data demonstrate that pharyngeal cell surface glycan structures directly impact GAS biofilm formation in a strain and glycan specific fashion.}, } @article {pmid33157493, year = {2021}, author = {Matsugishi, A and Aoki-Nonaka, Y and Yokoji-Takeuchi, M and Yamada-Hara, M and Mikami, Y and Hayatsu, M and Terao, Y and Domon, H and Taniguchi, M and Takahashi, N and Yamazaki, K and Tabeta, K}, title = {Rice peptide with amino acid substitution inhibits biofilm formation by Porphyromonas gingivalis and Fusobacterium nucleatum.}, journal = {Archives of oral biology}, volume = {121}, number = {}, pages = {104956}, doi = {10.1016/j.archoralbio.2020.104956}, pmid = {33157493}, issn = {1879-1506}, mesh = {Amino Acid Substitution ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fusobacterium nucleatum/*drug effects/growth & development ; Oryza/*chemistry ; Peptides/*pharmacology ; Plant Proteins/pharmacology ; Porphyromonas gingivalis/*drug effects/growth & development ; }, abstract = {OBJECTIVE: Rice peptide has antibacterial properties that have been tested in planktonic bacterial culture. However, bacteria form biofilm at disease sites and are resistant to antibacterial agents. The aim of this study was to clarify the mechanisms of action of rice peptide and its amino acid substitution against periodontopathic bacteria and their antibiofilm effects.

DESIGN: Porphyromonas gingivalis and Fusobacterium nucleatum were treated with AmyI-1-18 rice peptide or its arginine-substituted analog, G12R, under anaerobic conditions. The amount of biofilm was evaluated by crystal violet staining. The integrity of the bacteria cytoplasmic membrane was studied in a propidium iodide (PI) stain assay and transmission electron microscopy (TEM).

RESULTS: Both AmyI-1-18 and G12R inhibited biofilm formation of P. gingivalis and F. nucleatum; in particular, G12R inhibited F. nucleatum at lower concentrations. However, neither peptide eradicated established biofilms significantly. According to the minimum inhibitory concentration and minimum bactericidal concentration against P. gingivalis, AmyI-1-18 has bacteriostatic properties and G12R has bactericidal activity, and both peptides showed bactericidal activity against F. nucleatum. PI staining and TEM analysis indicated that membrane disruption by G12R was enhanced, which suggests that the replacement amino acid reinforced the electostatic interaction between the peptide and bacteria by increase of cationic charge and α-helix content.

CONCLUSIONS: Rice peptide inhibited biofilm formation of P. gingivalis and F. nucleatum, and bactericidal activity via membrane destruction was enhanced by amino acid substitution.}, } @article {pmid33157445, year = {2021}, author = {Roveto, PM and Gupta, A and Schuler, AJ}, title = {Effects of surface skewness on local shear stresses, biofilm activity, and microbial communities for wastewater treatment.}, journal = {Bioresource technology}, volume = {320}, number = {Pt A}, pages = {124251}, doi = {10.1016/j.biortech.2020.124251}, pmid = {33157445}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; *Water Purification ; }, abstract = {This study's objective was to assess attachment surface skewness (asymmetric surface height variation) effects on biofilm development. 3D printed molds were used to create surfaces with 300 μm features to provide opposite skewness but identical roughness values. Surfaces with negative skewness had consistently greater nitrite oxidation and biomass growth than other surfaces during biofilm development when studied in annular bioreactor systems. CFD modelling predicted local shear stress differences that could explain experimental results. 16 s rRNA gene amplicon sequencing revealed population differences, including relatively high Acinetobacter and Terrimonas fractions on the negative skew surfaces, and PCoA analyses indicated the flat surface populations diverged from the skew surfaces by the study's end. The results suggest skewness is particularly important in systems where biofilms have not overgrown surface features, as in system startup, thin biofilms, and shorter time frame studies, which includes much previous microbial attachment research.}, } @article {pmid33156827, year = {2020}, author = {Poh, WH and Lin, J and Colley, B and Müller, N and Goh, BC and Schleheck, D and El Sahili, A and Marquardt, A and Liang, Y and Kjelleberg, S and Lescar, J and Rice, SA and Klebensberger, J}, title = {The SiaABC threonine phosphorylation pathway controls biofilm formation in response to carbon availability in Pseudomonas aeruginosa.}, journal = {PloS one}, volume = {15}, number = {11}, pages = {e0241019}, pmid = {33156827}, issn = {1932-6203}, mesh = {Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Carbon/*metabolism ; Crystallography, X-Ray ; Fumonisins/pharmacology ; Humans ; Microscopy, Electron, Scanning ; Models, Molecular ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Phosphoprotein Phosphatases/chemistry/genetics/metabolism ; Phosphorylation ; Protein Kinases/chemistry/genetics/metabolism ; Pseudomonas aeruginosa/genetics/pathogenicity/*physiology ; Signal Transduction ; Threonine/*metabolism ; }, abstract = {The critical role of bacterial biofilms in chronic human infections calls for novel anti-biofilm strategies targeting the regulation of biofilm development. However, the regulation of biofilm development is very complex and can include multiple, highly interconnected signal transduction/response pathways, which are incompletely understood. We demonstrated previously that in the opportunistic, human pathogen P. aeruginosa, the PP2C-like protein phosphatase SiaA and the di-guanylate cyclase SiaD control the formation of macroscopic cellular aggregates, a type of suspended biofilms, in response to surfactant stress. In this study, we demonstrate that the SiaABC proteins represent a signal response pathway that functions through a partner switch mechanism to control biofilm formation. We also demonstrate that SiaABCD functionality is dependent on carbon substrate availability for a variety of substrates, and that upon carbon starvation, SiaB mutants show impaired dispersal, in particular with the primary fermentation product ethanol. This suggests that carbon availability is at least one of the key environmental cues integrated by the SiaABCD system. Further, our biochemical, physiological and crystallographic data reveals that the phosphatase SiaA and its kinase counterpart SiaB balance the phosphorylation status of their target protein SiaC at threonine 68 (T68). Crystallographic analysis of the SiaA-PP2C domain shows that SiaA is present as a dimer. Dynamic modelling of SiaA with SiaC suggested that SiaA interacts strongly with phosphorylated SiaC and dissociates rapidly upon dephosphorylation of SiaC. Further, we show that the known phosphatase inhibitor fumonisin inhibits SiaA mediated phosphatase activity in vitro. In conclusion, the present work improves our understanding of how P. aeuruginosa integrates specific environmental conditions, such as carbon availability and surfactant stress, to regulate cellular aggregation and biofilm formation. With the biochemical and structural characterization of SiaA, initial data on the catalytic inhibition of SiaA, and the interaction between SiaA and SiaC, our study identifies promising targets for the development of biofilm-interference drugs to combat infections of this aggressive opportunistic pathogen.}, } @article {pmid33156436, year = {2021}, author = {Matiadis, D and Karagiaouri, M and Mavroidi, B and Nowak, KE and Katsipis, G and Pelecanou, M and Pantazaki, A and Sagnou, M}, title = {Synthesis and antimicrobial evaluation of a pyrazoline-pyridine silver(I) complex: DNA-interaction and anti-biofilm activity.}, journal = {Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine}, volume = {34}, number = {1}, pages = {67-85}, pmid = {33156436}, issn = {1572-8773}, support = {MIS-5033021//State Scholarships Foundation/ ; }, mesh = {Acinetobacter baumannii/drug effects ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Coordination Complexes/chemical synthesis/chemistry/*pharmacology ; Escherichia coli/drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas aeruginosa/drug effects ; Pyrazoles/chemistry/*pharmacology ; Pyridines/chemistry/*pharmacology ; Silver/chemistry/*pharmacology ; }, abstract = {The emergence of resistant bacterial strains mainly due to misuse of antibiotics has seriously affected our ability to treat bacterial illness, and the development of new classes of potent antimicrobial agents is desperately needed. In this study, we report the efficient synthesis of a new pyrazoline-pyridine containing ligand L1 which acts as an NN-donor for the formation of a novel silver (I) complex 2. The free ligand did not show antibacterial activity. High potency was exhibited by the complex against three Gram-negative bacteria, namely Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumanii with the minimum inhibitory concentration (MIC) ranging between 4 and 16 μg/mL (4.2-16.7 μM), and excellent activity against the fungi Candida albicans and Cryptococcus neoformans (MIC ≤ 0.25 μg/mL = 0.26 μM). Moreover, no hemolytic activity within the tested concentration range was observed. In addition to the planktonic growth inhibition, the biofilm formation of both Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa was significantly reduced by the complex at MIC concentrations in a dose-dependent manner for Pseudomonas aeruginosa, whereas a biphasic response was obtained for MRSA showing that the sub-MIC doses enhanced biofilm formation before its reduction at higher concentration. Finally, complex 2 exhibited strong DNA binding with a large drop in DNA viscosity indicating the absence of classical intercalation and suggesting the participation of the silver ion in DNA binding which may be related to its antibacterial activity. Taken together, the current results reveal that the pyrazoline-pyridine silver complexes are of high interest as novel antibacterial agents, justifying further in vitro and in vivo investigation.}, } @article {pmid33155359, year = {2021}, author = {Burov, VE and Li, J and Meng, J}, title = {Nitrogen removal from domestic wastewater in a novel hybrid anoxic-oxic biofilm reactor at different reflux ratios.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {6}, pages = {865-874}, doi = {10.1002/wer.1477}, pmid = {33155359}, issn = {1554-7531}, support = {51778171//National Natural Science Foundation of China/ ; 51908163//National Natural Science Foundation of China/ ; QA201928//Open Project of State Key Laboratory/ ; 2017M611376//China Postdoctoral Science Foundation/ ; LBH-Z17087//Postdoctoral Foundation of Hei Long Jiang Province/ ; }, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {A lab-scale hybrid anoxic-oxic biofilm reactor (HAOBR) with one anoxic compartment and two oxic compartments in sequence was constructed to treat domestic wastewater in this study. Performance of the HAOBR was evaluated at 25°C and hydraulic retention time 12 hr with reflux ratio increased from 100% to 300% by stages. The results showed that COD, NH 4 + - N , and TN removal presented an increasing trend with the increase of reflux ratio by stages. At the optimal reflux ratio of 300%, removal of COD, NH 4 + - N , and TN averaged 83.9%, 99.0%, and 80.8%, respectively. Analysis about pollutant concentration in each compartment of the HAOBR revealed that the excellent pollutant removal was mainly achieved by the cooperation of nitrification in 3rd oxic compartment and denitrification in 1st anoxic compartment. Denitrification in the anoxic zone of 2nd oxic compartment would also contribute to the nitrogen removal. The higher nitrogen removal of the HAOBR at the reflux ratio of 300% is attributed to the presence of the anammox in the 1st anoxic compartment, which is mainly due to the lower COD concentration in the compartment at the higher reflux ratio. PRACTITIONER POINTS: A hybrid anoxic-oxic baffled reactor was built to treat domestic wastewater. Effect of reflux ratio and mechanism of nitrogen removal were investigated. Reflux ratio 300% was favorable for COD, NH 4 + and TN removal. The removal of COD, NH 4 + and TN averaged 84.4%, 99.0% and 80.8%, respectively. Cooperation of nitrification, denitrification and anammox dominated the high nitrogen removal at the higher reflux ratio of 300%.}, } @article {pmid33154253, year = {2020}, author = {Deshamukhya, C and Das, BJ and Chetri, S and Paul, D and Chanda, DD and Banerjee, T and Bhattacharjee, A}, title = {Use of fluorescence foldscope as an effective tool for detection of biofilm formation in Pseudomonas aeruginosa.}, journal = {Indian journal of medical microbiology}, volume = {38}, number = {3 & 4}, pages = {397-400}, doi = {10.4103/ijmm.IJMM_20_118}, pmid = {33154253}, issn = {1998-3646}, mesh = {Agar ; Biofilms/*growth & development ; Coloring Agents ; Congo Red ; Culture Media ; Humans ; Microscopy, Fluorescence/*instrumentation ; Pseudomonas aeruginosa/*physiology ; }, abstract = {PURPOSE: Pseudomonas aeruginosa is an opportunistic pathogen with biofilm-forming ability, by the virtue of which they can evade the immune response and antimicrobial chemotherapy. Several methods have been designed for the detection of biofilms but require sophisticated instrumentation and expertise. The present study, therefore, used an improvised device, 'fluorescence foldscope' which is an origami-based fluorescence microscope as an easy and effective tool to detect biofilm formation.

METHODOLOGY: Three representatives of P. aeruginosa of clinical origin were taken for the study along with two reference strains PA01 and ATCC27853. The strains were cultured in Luria Bertani (LB) broth with and without carbapenem (imipenem and meropenem) and cephalosporin (ceftazidime, cefotaxime and ceftriaxone) pressure, respectively. The cultures were diluted to 1:100 in LB; seeded with sterile glass slides at 90° angle and incubated for 5 consecutive days. The slides were observed with fluorescence foldscope.

RESULTS: Fluorescence emission was observed in two test isolates CD1 and CD2 at 48 and 72 h, respectively, whereas no fluorescence was observed in CD3. The fluorescence observed in the isolates was not affected by 2 μg/ml carbapenem pressure, while with 2 μg/ml ceftazidime stress, a change in fluorescence was observed in CD2 in comparison to the fluorescence observed under normal growth condition.

CONCLUSION: Fluorescence foldscopy is an effective and reliable tool for the detection of biofilm formation in clinical isolates of P. aeruginosa under different laboratory conditions. Biofilm-forming P. aeruginosa worsens the medical condition and is difficult to eradicate. The present study came up with an effective and reliable tool for the detection of biofilm formation in clinical isolates of P. aeruginosa.}, } @article {pmid33153745, year = {2021}, author = {Jiang, Y and Khan, A and Huang, H and Tian, Y and Yu, X and Xu, Q and Mou, L and Lv, J and Zhang, P and Liu, P and Deng, L and Li, X}, title = {Corrigendum to "Using nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as biofilm support enhances oil-refinery wastewater treatment in a biofilm membrane bioreactor" [Sci. Total Environ., 646 (2019) 606-17/STOTEN-D-18-03954].}, journal = {The Science of the total environment}, volume = {760}, number = {}, pages = {143189}, doi = {10.1016/j.scitotenv.2020.143189}, pmid = {33153745}, issn = {1879-1026}, } @article {pmid33152529, year = {2021}, author = {Thornton, JM and Walker, JM and Sundarasivarao, PYK and Spur, BW and Rodriguez, A and Yin, K}, title = {Lipoxin A4 promotes reduction and antibiotic efficacy against Pseudomonas aeruginosa biofilm.}, journal = {Prostaglandins & other lipid mediators}, volume = {152}, number = {}, pages = {106505}, pmid = {33152529}, issn = {1098-8823}, support = {R01 AI128202/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Ciprofloxacin/pharmacology ; *Lipoxins ; *Pseudomonas aeruginosa ; Quorum Sensing/drug effects ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium commonly found in wound infections and airways of cystic fibrosis patients. P. aeruginosa readily forms biofilms which can reduce the efficacy of antibiotics used to eradicate the pathogen. We have previously shown that a Specialized Pro-resolving Mediator (SPM), Lipoxin A4 (LxA4) is a quorum sensing inhibitor which can reduce P. aeruginosa virulence. In this study, we examined the direct actions of LxA4 and RvD2 on P. aeruginosa biofilm formation and virulence gene expression. The influence of LxA4 on antibiotic efficacy and the combined effects on biofilm formation were also investigated. LxA4 and RvD2 reduced P. aeruginosa biofilm formation and virulence gene expression. LxA4 increased ciprofloxacin inhibition on biofilm formation but did not affect ciprofloxacin's action on non-adherent bacteria. On the other hand, LxA4 increased bacterial killing action of imipenem but did not affect imipenem's action on biofilm. We also found that LxA4 can increase ciprofloxacin's bacterial killing ability in established biofilm. Together these results suggest that LxA4 has direct effects on P. aeruginosa biofilm formation and can increase antibiotic efficacy directly.}, } @article {pmid33151037, year = {2021}, author = {Yi, X and Wang, C and Yu, X and Su, W and Yuan, Z}, title = {Chitosan/zinc nitrate microneedles for bacterial biofilm eradication.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {109}, number = {6}, pages = {911-920}, doi = {10.1002/jbm.b.34755}, pmid = {33151037}, issn = {1552-4981}, mesh = {Animals ; Biofilms/*growth & development ; Chitosan/*chemistry ; Escherichia coli/*physiology ; Mice ; *Needles ; Nitrates/*chemistry ; Staphylococcus aureus/*physiology ; Zinc Compounds/*chemistry ; }, abstract = {Chronic wounds are greatly health threatening owing to the increasing morbidity, and bacterial biofilm is a major cause of chronic wounds. The critical for bacterial biofilm eradication is overcome the barrier of extracellular polymeric substances (EPS) produced by the bacteria, and promote the diffusion of drugs within the biofilm. In this article, composite microneedles (MNs) of chitosan and zinc nitrate (CS-Zn[II] MNs) were investigated to eradicate bacterial biofilm. The CS-Zn(II) MNs combined the structure characteristic of MNs with the antibacterial properties of CS and Zn[2+] . The MNs can pierce the EPS due to the needle-like structure, and can transport directly the CS and Zn[2+] into the bacterial biofilm. The needle-like structure of MNs also increased the contact area between drug carrier and bacterial biofilm nearly 14-23% comparing with membrane without needle-like structure, and facilitated the diffusion of drugs. What is more, the synergistic effect of CS and Zn[2+] make the CS-Zn(II) MNs obtain excellent antibiofilm properties. Counting the colony forming units and bacterial live/dead staining tests confirmed the fascinating antibacterial abilities (up to 100% inhibition) and biofilm eradication properties, respectively, of the CS-Zn(II) MNs. The inhibition zone test shown that the antibiofilm effect of MNs was superior to membrane and the antibiofilm effect of MNs was become increasingly obvious along with the increase of the treatment time. Besides, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays proved that the CS-Zn(II) MNs possess brilliant cytocompatibility. These results indicate that the CS-Zn(II) MNs are promising method for bacterial biofilm eradication.}, } @article {pmid33148046, year = {2020}, author = {Panichikkal, J and Edayileveetil Krishnankutty, R}, title = {Rhizobacterial biofilm and plant growth promoting trait enhancement by organic acids and sugars.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {990-999}, doi = {10.1080/08927014.2020.1832219}, pmid = {33148046}, issn = {1029-2454}, mesh = {Acids ; *Biofilms ; Pseudomonas ; Soil Microbiology ; Sugars ; }, abstract = {In the study,Pseudomonas sp. K6 and Pseudomonas monteilii were found to form an enhanced biofilm when cultured in the presence of organic acids and sugars. Here, the highest biofilm could be observed for Pseudomonas sp. K6 (3.08 ± 0.13) and P. monteilii (1.99 ± 0.12) when cultured in presence of 10 µM malic acid. However, maximum production of indole 3 acetic acid (IAA) was observed with 25 µM succinic acid treatment for Pseudomonas sp. K6 (24.33 ± 0.57 µg ml[-1]) and with 25 µM galactose for P. monteilii (20 ± 0.0 µg ml[-1]). At the same time, Pseudomonas sp. K6 solubilized the highest quantity of phosphate in the presence of 50 µM citric acid (21.33 ± 0.0 µM) and P. monteilii was observed to produce 32.66 ± 1.25 µM soluble phosphate in the presence of 10 µM galactose. The results of the study demonstrate the role of organic acids and sugars in the enhancement of biofilm formation, IAA production and phosphate solubilization in selected Pseudomonas spp. and highlight the potential use of rhizobacteria in conjugation with supplement for the agricultural applications.}, } @article {pmid33147550, year = {2020}, author = {Madla-Cruz, E and De la Garza-Ramos, M and Romo-Sáenz, CI and Tamez-Guerra, P and Garza-Navarro, MA and Urrutia-Baca, V and Martínez-Rodríguez, MA and Gomez-Flores, R}, title = {Antimicrobial activity and inhibition of biofilm formation in vitro and on human dentine by silver nanoparticles/carboxymethyl-cellulose composites.}, journal = {Archives of oral biology}, volume = {120}, number = {}, pages = {104943}, doi = {10.1016/j.archoralbio.2020.104943}, pmid = {33147550}, issn = {1879-1506}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Carboxymethylcellulose Sodium/chemistry ; Cells, Cultured ; Dentin/*microbiology ; Fibroblasts/drug effects ; Gingiva/cytology ; Humans ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Silver/*pharmacology ; }, abstract = {OBJECTIVE: To evaluate the antimicrobial activity of a silver nanoparticles/carboxymethyl-cellulose (AgNPs/CMC) composite on in vitro and dentine disc heterogeneous biofilms.

DESIGN: AgNPs/CMC composite effect on normal human gingival fibroblast cells (HGF) viability was determined by the MTT reduction assay. In addition, we evaluated the antimicrobial effect of AgNPs/CMC composite on Candida albicans, Enterococcus faecalis, and Fusobacterium nucleatum growth in vitro and heterogeneous biofilms, as well as dentine disc biofilms.

RESULTS: Quasi-spherical AgNPs/CMC composites, with a mean 22.3 nm particle-size were synthesized. They were not toxic to HGF cells at concentrations tested that were antimicrobial, however they caused significant cytotoxicity (89 %, p <  0.05) at concentrations > 15 μg/mL. In vitro, they inhibited up to 67 %, 66 %, and 96 % C. albicans, E. faecalis, and F. nucleatum growth at concentrations ranging from 1.2 μg/mL to 9.6 μg/mL, as compared with untreated control. We also demonstrated significant (p <  0.05) 58 % biofilm reduction by 4.8 μg/mL AgNPs/CMC composite on human dentine discs.

CONCLUSION: AgNPs/CMC composite showed anti biofilm activity on monocultures, heterogenous cultures, and dentine discs, resulting a potentially effective alternative to prevent and eliminate infections after endodontic treatment.}, } @article {pmid33147125, year = {2020}, author = {Park, C and Shin, B and Kim, W and Cheong, H and Park, S and Park, W}, title = {Comparative genomics of wild-type and laboratory-evolved biofilm-overproducing Deinococcus metallilatus strains.}, journal = {Microbial genomics}, volume = {6}, number = {12}, pages = {}, pmid = {33147125}, issn = {2057-5858}, mesh = {Acetates/chemistry ; Bacterial Proteins/*genetics/radiation effects ; Biofilms/*growth & development/radiation effects ; Culture Media/chemistry ; Deinococcus/genetics/*growth & development/radiation effects ; Directed Molecular Evolution ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/radiation effects ; Genomics/*methods ; Glucose/chemistry ; Glyoxylates/chemistry ; Microbial Viability ; *Mutation ; Sequence Analysis, DNA ; Sequence Analysis, RNA ; Whole Genome Sequencing ; }, abstract = {Deinococcus metallilatus MA1002 was exposed to ultraviolet radiation to generate mutants with enhanced biofilm production. Two strains (nos 5 and 6) were then selected based on their high biofilm formation, as well as their possession of higher concentrations of extracellular matrix components (eDNA, protein and saccharides) than the wild-type (WT). Genomic sequencing revealed the presence of large genome deletions in a secondary chromosome in the mutants. Expression analyses of the WT and mutant strains indicated the upregulation of genes associated with exopolysaccharide synthesis and stress response. The mutant strains showed high mortality in glucose-supplemented (TYG) medium; however, cell death and biofilm formation were not increased in mutant cells grown under acetate- or glyoxylate-added media, suggesting that metabolic toxicity during glucose metabolism induced a high rate of cell death but improved biofilm formation in mutant strains. In damaged cells, eDNAs contributed to the enhanced biofilm formation of D. metallilatus.}, } @article {pmid33146404, year = {2021}, author = {Xia, Y and Jayathilake, PG and Li, B and Zuliani, P and Chen, J}, title = {CFD-DEM modelling of biofilm streamer oscillations and their cohesive failure in fluid flow.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {2}, pages = {918-929}, doi = {10.1002/bit.27619}, pmid = {33146404}, issn = {1097-0290}, support = {EP/K039083/1//Engineering and Physical Sciences Research Council/ ; }, mesh = {*Biofilms ; *Hydrodynamics ; *Models, Chemical ; *Stress, Mechanical ; }, abstract = {Biofilm streamer motion under different flow conditions is important for a wide range of industries. The existing work has largely focused on experimental characterisations of these streamers, which is often time-consuming and expensive. To better understand the physics of biofilm streamer oscillation and their interactions in fluid flow, a computational fluid dynamics-discrete element method model has been developed. The model was used to study the flow-induced oscillations and cohesive failure of single and multiple biofilm streamers. We have studied the effect of streamer length on the oscillation at varied flow rates. The predicted single biofilm streamer oscillations in various flow rates agreed well with experimental measurements. We have also investigated the effect of the spatial arrangement of streamers on interactions between two oscillating streamers in parallel and tandem arrangements. Furthermore, cohesive failure of streamers was studied in an accelerating fluid flow, which is important for slowing down biofilm-induced clogging.}, } @article {pmid33146329, year = {2020}, author = {Balhaddad, AA and Ayoub, HM and Gregory, RL}, title = {In-Vitro Model of Scardovia wiggsiae Biofilm Formation and Effect of Nicotine.}, journal = {Brazilian dental journal}, volume = {31}, number = {5}, pages = {471-476}, doi = {10.1590/0103-6440202003207}, pmid = {33146329}, issn = {1806-4760}, mesh = {Actinobacteria ; Biofilms ; *Dental Caries ; Dental Enamel ; Humans ; *Nicotine/pharmacology ; Streptococcus mutans ; }, abstract = {Recently, Scardovia wiggsiae has been reported to be strongly associated with caries formation. This study aimed to establish an in vitro model of S. wiggsiae biofilm and to investigate the effect of nicotine on S. wiggsiae colony-forming units (CFUs) growth. S. wiggsiae biofilm was grown overnight using brain-heart infusion (BHI) broth supplemented with 5 g of yeast extract/L (BHI-YE). The overnight culture was used as an inoculum to grow S. wiggsiae biofilm on standardized enamel and dentin samples. Samples were incubated with different nicotine concentrations (0, 0.5, 1, 2, 4, 8, 16 and 32 mg/mL) for 3 days. The dissociated biofilms were diluted, spiral plated on blood agar plates, and incubated for 24 h. CFUs/mL were quantified using an automated colony counter. A two-way ANOVA was used to compare the effect of different nicotine concentrations on S. wiggsiae CFUs. This study demonstrated that S. wiggsiae biofilm could be initiated and formed in vitro. Increased CFUs was observed through 0.5-4 mg/mL and 0.5-8 mg/mL of nicotine using enamel and dentin substrates, respectively. 16 and 32 mg/mL of nicotine were determined as the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), respectively. S. wiggsiae formed greater biofilm on enamel than dentin specimens in response to the nicotine stimulus. This study demonstrated the negative effect of smoking on increasing S. wiggsiae biofilm. Establishing S. wiggsiae biofilm in vitro may allow researchers in the future to have a better understanding of caries pathogenesis and bacterial interaction.}, } @article {pmid33146161, year = {2020}, author = {Vidallon, MLP and Teo, BM}, title = {Recent developments in biomolecule-based nanoencapsulation systems for antimicrobial delivery and biofilm disruption.}, journal = {Chemical communications (Cambridge, England)}, volume = {56}, number = {90}, pages = {13907-13917}, doi = {10.1039/d0cc05880g}, pmid = {33146161}, issn = {1364-548X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Capsules ; *Drug Delivery Systems ; Macromolecular Substances/chemistry/pharmacology ; Nanostructures/*chemistry ; }, abstract = {Biomolecules are very attractive nanomaterial components, generally, due to their biocompatibility, biodegradability, abundance, renewability, and sustainability, as compared to other resources for nanoparticle-based delivery systems. Biomolecule-based nanoencapsulation and nanodelivery systems can be designed and engineered for antimicrobial cargos in order to surmount classical and current challenges, including the emergence of multi-drug resistant strains of microorganisms, the low effectiveness and limitations in the applicability of the present antimicrobials, and biofilm formation. This feature article highlights the recent applications and capabilities of biomacromolecule-based nanomaterials for the delivery and activity enhancement of antimicrobials, and disruption of biofilms. Unique properties of some nanomaterials, arising from specific biomacromolecules, were also emphasized. We expect that this review will be helpful to researchers in engineering new types of antimicrobial nanocarriers, hybrid particles and colloidal systems with tailored properties.}, } @article {pmid33143246, year = {2020}, author = {Egorova, DA and Voronina, OL and Solovyev, AI and Kunda, MS and Aksenova, EI and Ryzhova, NN and Danilova, KV and Rykova, VS and Scherbakova, AA and Semenov, AN and Polyakov, NB and Grumov, DA and Shevlyagina, NV and Dolzhikova, IV and Romanova, YM and Gintsburg, AL}, title = {Integrated into Environmental Biofilm Chromobacterium vaccinii Survives Winter with Support of Bacterial Community.}, journal = {Microorganisms}, volume = {8}, number = {11}, pages = {}, pmid = {33143246}, issn = {2076-2607}, support = {MK-2241.2019.7//President Grant/ ; N 056-00078-19-00//Government Contract/ ; }, abstract = {Chromobacterium species are common in tropical and subtropical zones in environmental samples according to numerous studies. Here, we describe an environmental case of resident Chromobacterium vaccinii in biofilms associated with Carex spp. roots in Moscow region, Russia (warm-summer humid continental climate zone). We performed broad characterization of individual properties as well as surrounding context for better understanding of the premise of C. vaccinii survival during the winter season. Genome properties of isolated strains propose some insights into adaptation to habit and biofilm mode of life, including social cheaters carrying ΔluxR mutation. Isolated C. vaccinii differs from previously described strains in some biochemical properties and some basic characteristics like fatty acid composition as well as unique genome features. Despite potential to modulate membrane fluidity and presence of several genes responsible for cold shock response, isolated C. vaccinii did not survive during exposure to 4 °C, while in the complex biofilm sample, it was safely preserved for at least half a year in vitro at 4 °C. The surrounding bacterial community within the same biofilm with C. vaccinii represented a series of psychrophilic bacterial species, which may share resistance to low temperatures with other species within biofilm and provide C. vaccinii an opportunity to survive during the cold winter season.}, } @article {pmid33142941, year = {2020}, author = {Oh, YR and Ku, HM and Kim, D and Shin, SJ and Jung, IY}, title = {Efficacy of a Nickel-Titanium Ultrasonic Instrument for Biofilm Removal in a Simulated Complex Root Canal.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {21}, pages = {}, pmid = {33142941}, issn = {1996-1944}, abstract = {This study evaluated the effectiveness of NiTi ultrasonic tips for Enterococcus faecalis (E. faecalis) biofilm removal in simulated complex root canals. Sixty root canal models consisting of a 30-degree curved main canal and two lateral canals were constructed from polydimethylsiloxane and incubated with E. faecalis. Irrigants in root canals were activated using a manual syringe (SI), a stainless steel (SS) instrument, a nickel-titanium (Ni-Ti) ultrasonic instrument, or a sonic instrument (EA). Instruments of SI, SS, and NiTi-9 groups were placed 9 mm from the apex, whereas those in NiTi-2 and EA groups were placed 2 mm from the apex. The efficacy of each method was determined as the ratio of fluorescence concentration before and after activation. In the apical curved canal, the highest efficacy was found in the NiTi-2 group (99.40%), followed by SI (84.25%), EA (80.38%), SS (76.93%), and NiTi-9 (67.29%) groups. In lateral canals 1 and 2, the efficacy was the highest in the NiTi-2 group and the lowest in the SI group. The NiTi ultrasonic instrument could effectively remove biofilms in the curved canal and lateral canals. This instrument should be introduced close to the working length. An up-and-down motion of the activation instrument is recommended.}, } @article {pmid33139386, year = {2021}, author = {Pan, Y and Siddaramappa, S and Sandal, I and Dickerman, A and Bandara, AB and Inzana, TJ}, title = {The Role of luxS in Histophilus somni Virulence and Biofilm Formation.}, journal = {Infection and immunity}, volume = {89}, number = {2}, pages = {}, pmid = {33139386}, issn = {1098-5522}, mesh = {Animals ; Bacterial Proteins/genetics/*immunology ; Biofilms ; Carbon-Sulfur Lyases/genetics/*immunology ; Cattle ; Disease Models, Animal ; Genetic Variation ; Genotype ; Humans ; Lipopolysaccharides/*biosynthesis/*immunology ; Mice ; Pasteurellaceae/*genetics/*immunology/*pathogenicity ; Pasteurellaceae Infections/genetics/*immunology ; Quorum Sensing/immunology ; Sheep ; Virulence/*immunology ; }, abstract = {S-Ribosylhomocysteinase (LuxS) is required for the synthesis of the autoinducer-2 (AI-2) quorum-sensing signaling molecule in many Gram-negative bacteria. The bovine (and ovine) opportunistic pathogen Histophilus somni contains luxS and forms a biofilm containing an exopolysaccharide (EPS) in the matrix. Since biofilm formation is regulated by quorum sensing in many bacteria, the roles of luxS in H. somni virulence and biofilm formation were investigated. Although culture supernatants from H. somni were ineffective at inducing bioluminescence in the Vibrio harveyi reporter strain BB170, H. somniluxS complemented the biosynthesis of AI-2 in the luxS-deficient Escherichia coli strain DH5α. H. somni strain 2336 luxS was inactivated by transposon mutagenesis. RNA expression profiles revealed that many genes were significantly differentially expressed in the luxS mutant compared to that in the wild-type, whether the bacteria were grown planktonically or in a biofilm. Furthermore, the luxS mutant had a truncated and asialylated lipooligosaccharide (LOS) and was substantially more serum sensitive than the wild-type. Not surprisingly, the luxS mutant was attenuated in a mouse model for H. somni virulence, and some of the altered phenotypes were partially restored after the mutation was complemented with a functional luxS However, no major differences were observed between the wild-type and the luxS mutant in regard to outer membrane protein profiles, biofilm formation, EPS production, or intracellular survival. These results indicate that luxS plays a role in H. somni virulence in the context of LOS biosynthesis but not biofilm formation or other phenotypic properties examined.}, } @article {pmid33139237, year = {2020}, author = {Uzunbayir-Akel, N and Tekintas, Y and Yilmaz, FF and Ozturk, I and Okeer, M and Aydemir, SS and Cilli, FF and Hosgor-Limoncu, M}, title = {Effects of disinfectants and ciprofloxacin on quorum sensing genes and biofilm of clinical Pseudomonas aeruginosa isolates.}, journal = {Journal of infection and public health}, volume = {13}, number = {12}, pages = {1932-1938}, doi = {10.1016/j.jiph.2020.10.002}, pmid = {33139237}, issn = {1876-035X}, mesh = {Bacterial Proteins ; Biofilms ; Ciprofloxacin/pharmacology ; *Disinfectants/pharmacology ; Humans ; *Pseudomonas aeruginosa/genetics ; Quorum Sensing ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is one of the most virulent bacteria and quorum sensing (QS) genes have an importance on virulence factors such as biofilm that provide resistance against disinfectants and antibiotics.

OBJECTIVE: This study aimed to determine the minimum inhibitory concentrations of the disinfectants, to investigate the effects of disinfectants and ciprofloxacin on biofilm production mature biofilm of clinical P. aeruginosa isolates, and it was aimed to investigate the effects of the agents on the expression levels of several QS-related genes in the isolates.

METHODS: Minimum inhibitory concentration (MIC) levels of polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), quaternary ammonium compounds (QAC), glutaraldehyde (GLU) and ciprofloxacin (CIP) against clinical P. aeruginosa isolates were evaluated by microdilution method. Effects of the agents on the biofilm producing capacities of clonally unrelated nine strains were investigated by spectrophotometric method. Alterations in the expression of QS-related genes (lasI, lasR, rhlI and rhlR) were investigated by qPCR in three isolates that were CIP-susceptible and strong biofilm producer.

RESULTS: According to microdilution method results, three isolates were found as resistant, one isolate was found as intermediate susceptible and five isolates were found as susceptible to CIP, and CHX (7.81-31.25 μg/mL) had the lowest MIC against P. aeruginosa. CHX inhibited biofilm production levels of eight of nine isolates, and GLU and CIP inhibited six of nine isolates in the presence of agents at MIC levels. GLU inhibited the mature biofilm levels of three of nine isolates at MIC and MIC/4 levels and four of nine isolates at MIC/2 levels. Expression levels of QS-related genes were reduced or induced in the presence of different disinfectants.

CONCLUSIONS: More efforts are required to decrease the risk of ineffective and low-dose application of disinfectants and antimicrobials against bacteria. Targeting of QS-related genes may be a reasonable strategy for the inhibition of virulence factors in P. aeruginosa.}, } @article {pmid33139107, year = {2021}, author = {Chen, S and Xie, J and Wen, Z}, title = {Removal of pharmaceutical and personal care products (PPCPs) from waterbody using a revolving algal biofilm (RAB) reactor.}, journal = {Journal of hazardous materials}, volume = {406}, number = {}, pages = {124284}, doi = {10.1016/j.jhazmat.2020.124284}, pmid = {33139107}, issn = {1873-3336}, mesh = {Biofilms ; *Cosmetics ; Ecosystem ; *Pharmaceutical Preparations ; Waste Disposal, Fluid ; Wastewater ; *Water Pollutants, Chemical/analysis ; }, abstract = {The occurrence of Pharmaceutical and Personal Care Products (PPCPs) in the aquatic environment has raised concerns due to their accumulation in the ecosystem. This study aims to explore the feasibility of using a Revolving Algal Biofilm (RAB) reactor for PPCPs removal from waterbody. Five model PPCP compounds including ibuprofen, oxybenzone, triclosan, bisphenol A and N, N-diethyl-3-methylbenzamide (DEET) were mixed and added to the culture medium. It shows that PPCP removal efficiencies of the RAB reactor ranged from 70% to 100%. The degradation of PPCPs by the RAB reactor contributed > 90% PPCP removal while < 10% PPCPs removal was due to accumulation in the algal biomass. The nutrients removal performance of the RAB reactor was not affected by exposing to the PPCPs. The extracellular polysaccharides content of the biomass increased when exposing to PPCPs, while the extracellular proteins content remained constant. The Chl a content maintained constant in the PPCPs-treated biomass, but decreased in the biomass without PPCP treatment. It was also found that the microbial consortium of the RAB reactor was enriched with PPCPs degradation microorganisms with the progressing of feeding PPCPs. Collectively, this work demonstrates that the RAB system is a promising technology for removing PPCPs from wastewater.}, } @article {pmid33138034, year = {2020}, author = {Wang, L and Tkhilaishvili, T and Trampuz, A}, title = {Adjunctive Use of Phage Sb-1 in Antibiotics Enhances Inhibitory Biofilm Growth Activity versus Rifampin-Resistant Staphylococcus aureus Strains.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33138034}, issn = {2079-6382}, abstract = {Effective antimicrobials are crucial for managing Staphylococcus aureus implant-associated bone infections (IABIs), particularly for infections due to rifampin-resistant S. aureus (RRSA). Failure to remove the implant results in persistent infection; thus, prolonged suppressive antibiotic therapy may be a reasonable alternative. However, a high incidence of adverse events can necessitate the discontinuation of therapy. In this scenario, commercial Staphylococcal bacteriophage Sb-1 combined with antibiotics is an option, showing a promising synergistic activity to facilitate the treatment of biofilm infections. Therefore, we evaluated the efficacy of the inhibitory activity of five antibiotics (doxycycline, levofloxacin, clindamycin, linezolid, and rifampin) alone or combined with phage Sb-1 (10[6] PFU/mL) in a simultaneous and staggered manner, to combat five clinical RRSA strains and the laboratory strain MRSA ATCC 43300 in 72 h by isothermal microcalorimetry. The synergistic effects were observed when phage Sb-1 (10[6] PFU/mL) combined with antibiotics had at least 2 log-reduction lower concentrations, represented by a fractional biofilm inhibitory concentration (FBIC) of <0.25. Among the antibiotics that we tested, the synergistic effect of all six strains was achieved in phage/doxycycline and phage/linezolid combinations in a staggered manner, whereas a distinctly noticeable improvement in inhibitory activity was observed in the phage/doxycycline combination with a low concentration of doxycycline. Moreover, phage/levofloxacin and phage/clindamycin combinations also showed a synergistic inhibitory effect against five strains and four strains, respectively. Interestingly, the synergistic inhibitory activity was also observed in the doxycycline-resistant and levofloxacin-resistant profile strains. However, no inhibitory activity was observed for all of the combinations in a simultaneous manner, as well as for the phage/rifampin combination in a staggered manner. These results have implications for alternative, combined, and prolonged suppressive antimicrobial treatment approaches.}, } @article {pmid33137803, year = {2021}, author = {Gonik, E and Rodríguez Sartori, D and David Gara, P and Miñán, A and Fernández Lorenzo de Mele, M and Gonzalez, MC}, title = {Staphylococcus aureus biofilm eradication by the synergistic effect exerted by PEG-coated silicon dots immobilized in silica films and light irradiation.}, journal = {Nanotechnology}, volume = {32}, number = {9}, pages = {095105}, doi = {10.1088/1361-6528/abc6dd}, pmid = {33137803}, issn = {1361-6528}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Drug Synergism ; Glass ; Microbial Viability/drug effects ; Photosensitizing Agents/chemistry/*pharmacology ; Polyethylene Glycols/chemistry ; Quantum Dots ; Silicon/chemistry/*pharmacology ; Silicon Dioxide/chemistry ; Singlet Oxygen/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/*growth & development ; Wettability ; }, abstract = {Immobilization of PEG-covered silicon dots, PEGSiDs, on glass substrates was performed following a simple strategy involving particle embedding by a sol-gel process forming a silica film on glass slides. The obtained films, denoted as fSiO x -PEGSiD, constitute a water-wettable, strongly supported, photoluminescent glass coating. The films showed high capacity for photosensitizing singlet oxygen ([1]O2) in the UVA when immersed in water. Staphylococcus aureus colonies formed on fSiO x -PEGSiDs modified glasses revealed the inhibition of bacterial adhesion and bacterial growth leading to the formation of loosely-packed and smaller S. aureus colonies. Upon 350 nm light irradiation of the biofilmed fSiO x -PEGSiDs -modified glasses, S. aureus growth was inhibited and bacteria killed reducing the number of living bacteria by three orders of magnitude. Eradication of attached bacteria was achieved by the synergistic effect exerted by a less adherent fSiO x -PEGSiDs surface that inhibits biofilm formation and the ability of the surface to photosensitize [1]O2 to kill bacteria.}, } @article {pmid33137534, year = {2020}, author = {Azimi, A and Aslanimehr, M and Yaseri, M and Shadkam, M and Douraghi, M}, title = {Distribution of smf-1, rmlA, spgM and rpfF genes among Stenotrophomonas maltophilia isolates in relation to biofilm-forming capacity.}, journal = {Journal of global antimicrobial resistance}, volume = {23}, number = {}, pages = {321-326}, doi = {10.1016/j.jgar.2020.10.011}, pmid = {33137534}, issn = {2213-7173}, mesh = {Biofilms ; Drug Resistance, Microbial ; *Gram-Negative Bacterial Infections ; Humans ; Iran ; *Stenotrophomonas maltophilia/genetics ; }, abstract = {OBJECTIVES: The molecular mechanisms involved in biofilm formation inStenotrophomonas maltophilia are poorly understood. Here, we examined whether the presence of smf-1, rmlA, spgM and rpfF genes is associated with biofilm formation and antibiotic resistance in S. maltophilia.

METHODS: A total of 150 S. maltophilia isolates were collected from three tertiary-care hospitals in Iran and were identified through PCR amplification of the 23S rRNA gene. Biofilm formation was determined by microtitre plate assay. Presence of smf-1, rmlA, spgM and rpfF genes was examined by PCR.

RESULTS: Among the isolates examined, 148 (98.7%) were able to produce biofilm, of which 69 (46.0%) were strong biofilm-producers, whereas 32 (21.3%) and 47 (31.3%) were moderate and weak biofilm-producers, respectively. The frequency ofsmf-1, rmlA, spgM and rpfF was 99.3%, 98.0%, 97.3% and 70.0%, respectively. Statistical analysis indicated a direct correlation between presence of the rpfF gene and biofilm formation (P < 0.001). The high prevalence of smf-1 (99.3%) among the isolates is noted and there was a significant association between smf-1 and biofilm-forming ability (P < 0.01), but lower than rpfF. Additionally, a direct association was found between resistance to ticarcillin/clavulanate, ceftazidime, ciprofloxacin and doxycycline and strong biofilm formation in the S. maltophilia isolates (P < 0.01).

CONCLUSION: This study demonstrated thatS. maltophilia clinical isolates significantly differ in biofilm-forming ability. Moreover, presence of rpfF and smf-1, but not spgM, could be associated with biofilm formation. This study highlights the importance of rpfF in formation of biofilm compared with the other genes involved.}, } @article {pmid33136443, year = {2021}, author = {Vudhya Gowrisankar, Y and Manne Mudhu, S and Pasupuleti, SK and Suthi, S and Chaudhury, A and Sarma, PVGK}, title = {Staphylococcus aureus grown in anaerobic conditions exhibits elevated glutamine biosynthesis and biofilm units.}, journal = {Canadian journal of microbiology}, volume = {67}, number = {4}, pages = {323-331}, doi = {10.1139/cjm-2020-0434}, pmid = {33136443}, issn = {1480-3275}, mesh = {Anaerobiosis ; Bacteria/classification/genetics ; Biofilms/*growth & development ; Genetic Variation ; Glutamate-Ammonia Ligase/genetics/metabolism ; Glutamine/*biosynthesis ; Humans ; Methicillin-Resistant Staphylococcus aureus/growth & development/metabolism/pathogenicity/physiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/growth & development/metabolism/pathogenicity/*physiology ; }, abstract = {The enormous spread of Staphylococcus aureus infections through biofilms is a major concern in hospital-acquired infections. Biofilm formation by S. aureus on any surface is facilitated by adjusting its redox status. This organism is a facultative anaerobe shift more towards reductive conditions by enhancing nitrogen metabolism where glutamine synthesis plays a key role. Glutamine is synthesized by glutamine synthetase (GS) encoded by the glnA gene. The gene was amplified by PCR from the chromosomal DNA of S. aureus, sequenced (HQ329146.1), and cloned. The pure recombinant GS exhibited Km of 11.06 ± 0.05 mmol·L[-1] for glutamate and 2.4 ± 0.03 mmol·L[-1] for ATP. The glnA gene sequence showed a high degree of variability with its human counterpart, while it was highly conserved in bacteria. Structural analysis revealed that the GS structure of S. aureus showed close homology with other Gram-positive bacteria and exhibited a high degree of variation with Escherichia coli GS. In the present study, we observed the increased presence of GS activity in multidrug-resistant strains of S. aureus with elevated biofilm units, grown in brain heart infusion broth; among them methicillin-resistant strains S. aureus LMV 3, 4, and 5 showed higher biofilm units. All these results explain the important role of glutamine biosynthesis with elevated biofilm units in the pathogenesis of S. aureus.}, } @article {pmid33134957, year = {2020}, author = {Mouhat, M and Moorehead, R and Murdoch, C}, title = {In vitro Candida albicans biofilm formation on different titanium surface topographies.}, journal = {Biomaterial investigations in dentistry}, volume = {7}, number = {1}, pages = {146-157}, pmid = {33134957}, issn = {2641-5275}, abstract = {OBJECTIVES: To investigate if differences in titanium implant surface topography influence Candida albicans biofilm formation.

MATERIALS AND METHODS: Titanium discs were prepared and characterized using a profilometer: Group A (R a 0.15 µm, smooth), Group B (R a 0.64 µm, minimally rough) and Group C (R a 1.3 µm, moderately rough). Contact angle and surface free energy (SFE) were determined for each group. Non-preconditioned titanium discs were incubated with C. albicans for 24 h. In additional experiments, the titanium discs were initially coated with human saliva, bovine serum albumin or phosphate-buffered saline for 2 h before incubation with C. albicans for 24 h. The amount of fungal biofilm formation was quantified using a colorimetric assay.

RESULTS: C. albicans biofilm formation was significantly lower (p < 0.05) on the minimally rough titanium surface compared to smooth and moderately rough surfaces. The titanium surface displaying the lowest SFE (Group B) was associated with significantly lower (p < 0.05) C. albicans biofilm formation than the other two groups. Salivary coating resulted in greater adherence of C. albicans with increased surface roughness.

CONCLUSIONS: The minimally rough titanium discs displayed lowest SFE compared to smooth and moderately rough surfaces and showed the least C. albicans biofilm formation. This study demonstrated that C. albicans biofilm formation increased in a SFE-dependent manner. These findings suggest that SFE might be a more explanatory factor for C. albicans biofilm formation on titanium surfaces than roughness. The presence of a pellicle coating may negate the impact of SFE on C. albicans biofilm formation on titanium surfaces.}, } @article {pmid33134581, year = {2020}, author = {Guzman, JPMD and De Las Alas, TPL and Lucban, MC and Sevilla, CEC}, title = {Green tea (Camellia sinensis) extract inhibits biofilm formation in acyl homoserine lactone-producing, antibiotic-resistant Morganella morganii isolated from Pasig River, Philippines.}, journal = {Heliyon}, volume = {6}, number = {10}, pages = {e05284}, pmid = {33134581}, issn = {2405-8440}, abstract = {The drastic development of urban districts around the world has caused changes in the environment, specifically on metropolitan waterways such as the Pasig River in the Philippines. These significant changes resulted in diversity of microorganisms and their mechanisms employed such as antibiotic resistance and their communication system or quorum sensing (QS). In this study, four bacterial isolates from Pasig River, identified as Aeromonas salmonicida, Acinetobacter sp., Morganella morganii, and Citrobacter freundii, were observed to employ short-chain acyl homoserine lactone (AHL) as their signalling molecule based on in vitro assays using the biosensor strain Chromobacterium violaceum CV026. Furthermore, M. morganii isolate was shown to be resistant to chloramphenicol. This poses a significant threat not just to public health but also to the aquatic life present in the river. Thus, green tea (Camellia sinensis) extract was tested for its capability to inhibit in vitro biofilm formation in M. morganii, as well as the short-chain acyl homoserine lactone QS system using C. violaceum ATCC 12472. Results showed that the extract significantly (p < 0.05) inhibited biofilm formation in M. morganii at as low as 62.5 μg/mL (31.55%). Increasing the concentration (500 μg/mL) did not significantly (p > 0.05) enhance the activity (41.21%). Furthermore, the extract also inhibited pigmentation in C. violaceum ATCC 12472, suggesting QS inhibition. This study adds into record the production of short-chain AHLs by Aeromonas salmonicida, Acinetobacter sp., Morganella morganii, and Citrobacter freundii, as well as the potential of green tea extract as inhibitor of biofilm formation in antibiotic-resistant M. morganii possibly through QS inhibition.}, } @article {pmid33134137, year = {2020}, author = {Sah, SK and Rasool, U and Hemalatha, S}, title = {Andrographis paniculata extract inhibit growth, biofilm formation in multidrug resistant strains of Klebsiella pneumoniae.}, journal = {Journal of traditional and complementary medicine}, volume = {10}, number = {6}, pages = {599-604}, pmid = {33134137}, issn = {2225-4110}, abstract = {BACKGROUND AND AIM: Andrographis paniculata (Kalmegh), a valuable ancient medicinal herb is used in the treatment of several diseases in most Asian countries including India. Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infections in human. We have investigated the antimicrobial susceptibility and the presence of AmpC gene in K. pneumoniae strain isolated from the sputum of the patient.

EXPERIMENTAL PROCEDURE: Antibiotic susceptibility test and phenotypic detection of AmpC/ESBL beta-lactamase were performed by combined disc diffusion test. The CEA of A. paniculata was analyzed for its antibacterial potential against susceptible and resistant strains of K. pneumoniae through the broth microdilution method. Molecular detection of AmpC gene was carried by polymerase chain reaction (PCR).

RESULTS: Antibiotic susceptibility test displayed that the clinical isolate of K. pneumoniae were resistant towards cephalosporins, quinolone and monobactam but susceptible to carbapenems. Combined disk diffusion demonstrated AmpC[+ve]/ESBL[-ve] beta-lactamase. 250 μg/ml of CEA extract confirmed the inhibition of bacterial growth and biofilm formation compared to the antibiotic. CEA treated K. pneumoniae displayed a reduction of AmpC by polymerase chain reaction.

CONCLUSION: The present study illustrates that CEA extract of A. paniculata demonstrated potentiality to control K. pneumoniae growth and biofilm formation. CEA was able to suppress the expression of gene encoding AmpC. This study proves to be an economical approach to control the growth of K. pneumoniae which causes serious infections.}, } @article {pmid33133324, year = {2020}, author = {Yang, K and Liu, S and Li, H and Du, N and Yao, J and He, Q and Du, Y}, title = {NDM-1-Positive K. pneumoniae at a Teaching Hospital in Southwestern China: Clinical Characteristics, Antimicrobial Resistance, Molecular Characterization, Biofilm Assay, and Virulence.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2020}, number = {}, pages = {9091360}, pmid = {33133324}, issn = {1712-9532}, abstract = {BACKGROUND: The emergence of the NDM-1-positive Klebsiella pneumoniae (K. pneumoniae) strains has led to limited therapeutic options for clinical treatment. Understanding the clinical characteristics, antimicrobial resistance, biofilm assay, and the virulence genes of these isolated strains is of great significance.

METHODS: The polymerase chain reaction (PCR) was used to screen isolated NDM-1-positive K. pneumoniae. The clinical information of the patients was collected from medical records. The NDM-1-positive K. pneumoniae isolates were subjected to antimicrobial susceptibility testing and multilocus sequence typing. Sixty strains of NDM-1-negative K. pneumoniae isolated during the same period were collected as the control group for the virulence analysis. The virulence phenotype of the strains was preliminarily evaluated by the string test and crystal violet semiquantitative biofilm formation experiment. PCR combined with gene sequencing was used to detect common high toxicity capsule genes (K1, K2, K5, K20, K54, and K57) and common virulence-related genes (entB, ybtS, ureA, ycf, WabG, FimH, uge, iutA, KfuB, aerobactin, rmpA, magA, Alls, IrnN, and VatD).

RESULTS: In the 30 nonduplicated NDM-1-positive K. pneumoniae isolates, 43.33% (13/30) of the patients had a history of a stay in the neonatal intensive care unit (NICU). All of the isolates exhibited multidrug resistance. Nine STs were identified, 77% (10/13) strains from the NICU were ST11. The NDM-1-positive K. pneumoniae string tests were all negative, and 35% (21/60) NDM-1-negative K. pneumoniae were positive. The ratios of NDM-1-positive K. pneumoniae isolates biofilm formation ability according to strong, medium, and weak classification were 67%, 23%, and 10%, respectively. NDM-1-negative K. pneumoniae isolates were 60%, 25%, and 15%, respectively. There was no statistical difference between the two groups (t = 0.61, P=0.2723). The virulence-associated genes with more than 80% of detection rates among the 30 NDM-1-positive K. pneumoniae isolates included entB (100%, 30/30), ybtS (93.33%, 28/30), ureA (90%, 27/30), ycf (83.33%, 25/30), and wabG (90%, 27/30). KfuB and iutA were detected at prevalence of 3.33% and 13.33%. vatD, allS, iroN, aerobactin, and rmpA were not detected. In the NDM-1-negative K. pneumoniae, all other 14 virulence genes except VatD were detected. After statistical analysis, FimH, WabG, ycf, iutA, kfuB, aerobactin, rmpA, and Alls virulence genes, P < 0.005, there was a statistical difference.

CONCLUSION: NDM-1-positive K. pneumoniae exhibited multidrug resistance, MLST typing is mainly ST11, there is small clonal dissemination in the NICU in the hospital, and the NDM-1-positive K. pneumoniae virulence genes carrier rate is lower than the NDM-1-negative K. pneumoniae virulence genes carrier rate.}, } @article {pmid33133249, year = {2020}, author = {Rusu, D and Stratul, SI and Calniceanu, H and Boariu, M and Ogodescu, A and Milicescu, S and Didilescu, A and Roman, A and Surlin, P and Locovei, C and Chiperi, M and Solomon, S and Nica, L}, title = {A qualitative and semiquantitative SEM study of the morphology of the biofilm on root surfaces of human teeth with endodontic-periodontal lesions.}, journal = {Experimental and therapeutic medicine}, volume = {20}, number = {6}, pages = {201}, pmid = {33133249}, issn = {1792-0981}, abstract = {Over the last decades, scanning electron microscopy (SEM) proved to be invaluable for ultrastructural investigation, allowing imaging of the overall appearance and/or specific features of oral biofilms, e.g., microbial colonies and individual cells, glycocalyx, the presence of inorganic products. The aim of this study was the observation and evaluation of the morphology of the biofilm of endodontic-periodontal lesions (EPL) with a modified protocol involving a simplified histologic sample preparation and a low-vacuum SEM examination method. Twenty-one teeth with endodontic-periodontal involvement, extracted for periodontal reasons, were carefully washed with saline, underwent fixation in modified Karnovsky solution and were dehydrated in alcohol series. Samples were examined under low-vacuum SEM. Radicular surfaces were evaluated qualitatively and semiquantitatively for several characteristics, including the presence of bacterial types, the biofilm morphology and the content of root resorptions. Radicular surfaces were divided in four conventional zones Surfaces were evaluated for several characteristics: Presence of bacterial types, biofilm morphology, presence of root resorptions. High-quality images, relevant for endodontic-periodontal biofilms were collected. Continuous, established biofilm was found on all examined surfaces, its detection varying from 19% of the samples on the wall of cemental cone to 52.3% on the radicular surface of the periodontal pocket. Observed microorganisms included cocci, rods an filaments. Spirils and motile bacteria were only accidentally found. SEM investigation of surfaces involved in EPL revealed less surfaces covered by mature biofilm (in only 28.5% of the samples in the 'transition zone'), especially rods and filaments associated with cemental resorptions and calculus. Biofilm elements were better represented in periodontal pockets than in other zones of EPL (detected in up to 81% of the samples). A strong correlation between mature biofilm and the presence of cocci appears on all investigated zones (P<0.01). Microbiota appeared to be morphologically similar in apical and periodontal areas, especially in old EPL.}, } @article {pmid33131824, year = {2021}, author = {Verma, P and Singh, N and Anand, S}, title = {Short communication: A competitive exclusion study reveals the emergence of Bacillus subtilis as a predominant constitutive microorganism of a whey reverse osmosis membrane biofilm matrix.}, journal = {Journal of dairy science}, volume = {104}, number = {1}, pages = {221-227}, doi = {10.3168/jds.2020-18478}, pmid = {33131824}, issn = {1525-3198}, mesh = {Acinetobacter ; Bacillus licheniformis/isolation & purification ; Bacillus subtilis/*isolation & purification ; *Biofilms/growth & development ; Caseins ; Extracellular Polymeric Substance Matrix ; Osmosis ; Protein Hydrolysates ; Whey/*microbiology ; }, abstract = {Microbial attachment and colonization on separation membranes lead to biofilm formation. Some isolates within the biofilm microflora acquire greater resistance to the chemical cleaning protocols on prolonged use of membranes. It is thus likely that the constitutive microflora might compete with each other and result in certain species emerging as predominant, especially within older biofilms. To understand the microbial interactions within biofilms, the emergence of predominance was studied in the current investigation. An 18-mo-old reverse osmosis membrane was procured from a whey processing plant. The membrane pieces (2.54 × 2.54 cm[2]) were neutralized by dipping in Letheen broth. The resuscitation step was done in tryptic soy broth (TSB) at 37°C, followed by plating on tryptic soy agar (TSA) to recover the constitutive microflora. Distinct colonies of isolates were further identified using MALDI-TOF as Bacillus licheniformis, Exiguobacterium aurantiacum, Acinetobacter radioresistens, Bacillus subtilis (rpoB sequencing), and 1 unidentified species each of Exiguobacterium and Bacillus. Further, the competitive exclusion study helped establish the emergence of predominance using a co-culturing technique. Fifteen combinations (of 2 isolates each) were prepared from the isolates. Pure cultures of the respective isolates were spiked in a ratio of 1:1 in TSB and incubated at 37°C for 24 h, followed by plating on TSA. The enumerated colonies were distinguished based on colony morphology, Gram staining, and MALDI-TOF to identify the type of the isolate. Plate counts of B. subtilis emerged as predominant with mean log counts of 7.22 ± 0.22 cfu/mL. The predominance of B. subtilis was also validated using the process of natural selection in a multispecies growth environment. In this instance, the TSB culture with overnight-incubated membrane piece (with mixed-species biofilm) at 37°C for 12 h was inoculated in fresh TSB and incubated for the second cycle. Overall, 5 such sequential broth-culture incubation cycles were carried out, followed by pour plating on TSA plates, at the end of each cycle. The isolates obtained were identified using a similar methodology as mentioned above. The fifth subsequent transfer depicted the presence of only 1 B. subtilis isolate on plating, thereby validating its predominance under the conditions of the experiment.}, } @article {pmid33130966, year = {2020}, author = {Gharaghani, M and Taghipour, S and Zarei Mahmoudabadi, A}, title = {Molecular identification, biofilm formation and antifungal susceptibility of Rhodotorula spp.}, journal = {Molecular biology reports}, volume = {47}, number = {11}, pages = {8903-8909}, pmid = {33130966}, issn = {1573-4978}, support = {9722//Ahvaz Jundishapur University of Medical Sciences/ ; }, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Caspofungin/pharmacology ; DNA, Fungal/genetics ; DNA, Ribosomal Spacer/genetics ; Fluconazole/pharmacology ; Humans ; Imidazoles/*pharmacology ; Itraconazole/pharmacology ; Microbial Sensitivity Tests/*methods ; Phylogeny ; Rhodotorula/classification/*drug effects/physiology ; Species Specificity ; Triazoles/pharmacology ; Voriconazole/pharmacology ; }, abstract = {Luliconazole is an imidazole antifungal agent used in topical form for the treatment of onychomycosis and dermatophytosis. In vitro activity of luliconazole against dermatophytes, Candida, black fungi, Fusarium and Aspergillus species have been investigated. Rhodotorula spp. are environmental yeasts and emerged as opportunistic pathogens among immunocompromised patients. Rhodotorula's human infections are usually resistant to treatment with antifungal drugs especially triazoles and echinocandins. The present study aimed at the molecular detection of environmental isolates of Rhodotorula spp. Then, antifungal efficacy of luliconazole was evaluated against isolates and compared to other routine systemic antifungals including; caspofungin, posaconazole, fluconazole, itraconazole, amphotericin B, and voriconazole. The biofilm production of Rhodotorula isolates was also evaluated. In this study, 39 isolates of Rhodotorula spp. were isolated from the environment, detected using molecular methods, and tested against luliconazole. Then, the anti-fungal activity of luliconazole compared with several routine antifungals. Also, biofilm formation by using a crystal violet staining assay was performed. Our finding showed that luliconazole has a very high minimum inhibitory concentration (MIC) value (1-8 µg/ml) against Rhodotorula spp. Besides, 100% of Rhodotorula strains were resistant to caspofungin, followed by fluconazole 94.7% and voriconazole 74.4%. Amphotericin B was demonstrated excellent in vitro activity against this genus. Our result indicated that 59% of Rhodotorula spp. were in the mid-range of biofilm production. Our results indicated that luliconazole does not effective against the genus Rhodotorula. Furthermore, amphotericin B is the best drug against this genus in comparison to caspofungin and other azole drugs.}, } @article {pmid33128980, year = {2021}, author = {Hu, J and Xu, Y and Chen, Y and Chen, J and Dong, H and Yu, J and Qiang, Z and Qu, J and Chen, J}, title = {Formation of carbonaceous and nitrogenous iodinated disinfection byproducts from biofilm extracellular polymeric substances by the oxidation of iodide-containing waters with lead dioxide.}, journal = {Water research}, volume = {188}, number = {}, pages = {116551}, doi = {10.1016/j.watres.2020.116551}, pmid = {33128980}, issn = {1879-2448}, mesh = {Animals ; Biofilms ; CHO Cells ; Cricetinae ; Cricetulus ; *Disinfectants ; Disinfection ; Extracellular Polymeric Substance Matrix/chemistry ; Halogenation ; Iodides ; Lead ; Nitrogen/analysis ; *Water Pollutants, Chemical/analysis ; *Water Purification ; }, abstract = {Lead dioxide (PbO2) is an important form of lead mineral scales in drinking water pipes. Iodide (I[-]) widely presents in source waters and can be thermodynamically oxidized by PbO2 to the reactive iodine species (I2/HOI). Biofilm extracellular polymeric substances (EPS) are nonnegligible precursors of disinfection byproducts (DBPs). The aim was to study the oxidation of I[-] by PbO2 and formation of iodinated DBPs (I-DBPs) from EPS. At a high molar ratio of PbO2 to I[-] (> 100), the observed rate constants of I[-] oxidation decreased as pH increased from 6.0 to 9.0 with an H[+] dependence of 0.79, and the rate constant (k) was 1.6 × 10[11] M[-2.79] s[-1]. Most of formed I2/HOI (> 92%) was transformed to organic iodine in the presence of EPS. EPS had a lower formation potential (FP) of carbonaceous I-DBPs (C-IDBPs), while a higher that of nitrogenous I-DBPs (N-IDBPs) than HA, resulting in a higher Chinese Hamster Ovary cell cytotoxicity. Generally, the formation of I-DBPs decreased with the increase of pH due to the reduction of surface positive charge and electrochemical driving force. PbO2 dose and I[-] concentration also had a significant effect on the I-DBPs formation. EPS proteins had a higher FP of both C- and N-IDBPs than polysaccharides on account of more electrophilic sites and higher nitrogen content. In proteins, aspartic acid was the main contributor to triiodomethane and iodoacetic acids formation, whereas aspartic acid, asparagine and tyrosine were the major precursors of diiodoacetonitrile and diiodoacetamide. The study helps to improve the control strategy of I-DBPs when biofilm outbreaks in lead-containing water pipes.}, } @article {pmid33128581, year = {2021}, author = {Zhang, Y and Zhu, Y and Zuo, Y and Tang, C and Zhou, F and Cui, X and Wang, L}, title = {Effects of Rhein-8-O-β-D-glucopyranoside on the Biofilm Formation of Streptococcus mutans.}, journal = {Current microbiology}, volume = {78}, number = {1}, pages = {323-328}, pmid = {33128581}, issn = {1432-0991}, support = {18JK0656//Special scientific research plan project of Shaanxi provincial department of education/ ; 2017sf-111//Key plan of Shaanxi provincial science and technology department/ ; 2015QN13//Youth scientific research fund project of Xi'an Medical College/ ; }, mesh = {Anthraquinones ; Bacterial Proteins/genetics ; Biofilms ; *Dental Caries ; Humans ; *Streptococcus mutans/genetics ; }, abstract = {Dental caries is the most frequent biofilm-related human infectious disease in the oral cavity. Streptococcus mutans is one of the primary etiological agents of dental caries. The aim of our study was to investigate the effects of rhein-8-O-β-D-glucopyranoside (Rg) on the development of S. mutans biofilms. Growth curves were generated, and biofilm oxygen sensitivity was detected after Rg treatment. The expression levels of luxS, brpA, ffh, recA, nth, and smx were analyzed by real-time PCR. The trypan blue exclusion assay was used to measure the effect of Rg on monocyte viability. The results showed that Rg could significantly inhibit the growth of S. mutans and suppress the biofilm formation of S. mutans in a concentration-dependent manner. In Rg-treated biofilms, the expression levels of luxS, brpA, ffh, recA, nth, and smx were all decreased. Our results further showed that Rg was nontoxic, as Rg did not affect monocyte viability or lactate dehydrogenase activity in the exposed cells. These results suggested that Rg inhibited the biofilm formation of S. mutans, and the decrease in luxS, brpA, ffh, recA, nth, and smx expression might contribute to the antibacterial effects of Rg.}, } @article {pmid33128546, year = {2020}, author = {Zúñiga, A and Solis, C and Cartes, C and Nourdin, G and Yañez, A and Romero, A and Haussmann, D and Figueroa, J}, title = {Transcriptional analysis of metabolic and virulence genes associated with biofilm formation in Piscirickettsia salmonis strains.}, journal = {FEMS microbiology letters}, volume = {367}, number = {21}, pages = {}, doi = {10.1093/femsle/fnaa180}, pmid = {33128546}, issn = {1574-6968}, mesh = {Animals ; Biofilms/*growth & development ; Chile ; Fish Diseases/*microbiology ; Gene Expression Profiling ; Genes, Bacterial/genetics ; Piscirickettsia/*genetics/metabolism/*pathogenicity ; Piscirickettsiaceae Infections/*microbiology ; Salmonidae/microbiology ; Virulence Factors/*genetics ; }, abstract = {Piscirickettsia salmonis is a facultative intracellular bacterium that generates piscirickettsiosis affecting salmonids in Chile. The bacterium has the adaptability to survive in the marine environment under multiple stressful conditions. In this sense, this work focused on the analysis of a gene battery associated with biofilm formation under different culture conditions and on the adaptability of this biofilm to different media. The results indicated that the strains LF-89, IBM-034 and IBM-040 were strong biofilm producers, evidencing adaptability to the media by increasing the amount of biofilm through successive growths. Transcript levels of six genes described in various bacteria and P. salmonis, considered to have metabolic functions, and playing a relevant role in biofilm formation, were analyzed to evaluate bacterial functionality in the biofilm. The genes mazE-mazF, implicated in biofilm and stress, were markedly overexpressed in the biofilm condition in the three strains. For its part, gene gltA, an indicator of metabolic activity and related to virulence inhibition in Salmonella typhimurium, also seems to restrain the pathogenesis process in P. salmonis by inhibiting the expression of the virulence-associated genes liso and tcf. Finally, the expression of the glnA gene suggests the use of glutamine as an essential element for the growth of the biofilm.}, } @article {pmid33128507, year = {2021}, author = {Dorado-Morales, P and Martínez, I and Rivero-Buceta, V and Díaz, E and Bähre, H and Lasa, I and Solano, C}, title = {Elevated c-di-GMP levels promote biofilm formation and biodesulfurization capacity of Rhodococcus erythropolis.}, journal = {Microbial biotechnology}, volume = {14}, number = {3}, pages = {923-937}, pmid = {33128507}, issn = {1751-7915}, mesh = {Biofilms ; Cyclic GMP/analogs & derivatives ; *Rhodococcus/genetics ; }, abstract = {Bacterial biofilms provide high cell density and a superior adaptation and protection from stress conditions compared to planktonic cultures, making them a very promising approach for bioremediation. Several Rhodococcus strains can desulfurize dibenzothiophene (DBT), a major sulphur pollutant in fuels, reducing air pollution from fuel combustion. Despite multiple efforts to increase Rhodococcus biodesulfurization activity, there is still an urgent need to develop better biocatalysts. Here, we implemented a new approach that consisted in promoting Rhodococcus erythropolis biofilm formation through the heterologous expression of a diguanylate cyclase that led to the synthesis of the biofilm trigger molecule cyclic di-GMP (c-di-GMP). R. erythropolis biofilm cells displayed a significantly increased DBT desulfurization activity when compared to their planktonic counterparts. The improved biocatalyst formed a biofilm both under batch and continuous flow conditions which turns it into a promising candidate for the development of an efficient bioreactor for the removal of sulphur heterocycles present in fossil fuels.}, } @article {pmid33128291, year = {2021}, author = {Guo, S and Huang, Q and Chen, Y and Wei, J and Zheng, J and Wang, L and Wang, Y and Wang, R}, title = {Synthesis and Bioactivity of Guanidinium-Functionalized Pillar[5]arene as a Biofilm Disruptor.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {60}, number = {2}, pages = {618-623}, doi = {10.1002/anie.202013975}, pmid = {33128291}, issn = {1521-3773}, mesh = {Anti-Bacterial Agents/*chemical synthesis/pharmacology ; Biofilms/drug effects ; Calixarenes/*chemistry ; Cefazolin/pharmacology ; Escherichia coli/physiology ; Guanidine/*chemistry ; Microscopy, Confocal ; Staphylococcus aureus/physiology ; }, abstract = {Due to the inherent resistance of bacterial biofilms to antibiotics and their serious threat to global public health, novel therapeutic agents and strategies to tackle biofilms are urgently needed. To this end, we designed and synthesized a novel guanidinium-functionalized pillar[5]arene (GP5) that exhibited high antibacterial potency against Gram-negative E. coli (BH101) and Gram-positive S. aureus (ATCC25904) strains. More importantly, GP5 effectively disrupted preformed E. coli biofilms by efficient penetration through biofilm barriers and subsequent destruction of biofilm-enclosed bacteria. Furthermore, host-guest complexation between GP5 and cefazolin sodium, a conventional antibiotic that otherwise shows negligible activity against biofilms, exhibited much enhanced, synergistic disruption activity against E. coli biofilms, thus providing a novel supramolecular platform to effectively disrupt biofilms.}, } @article {pmid33127897, year = {2020}, author = {Varadarajan, AR and Allan, RN and Valentin, JDP and Castañeda Ocampo, OE and Somerville, V and Pietsch, F and Buhmann, MT and West, J and Skipp, PJ and van der Mei, HC and Ren, Q and Schreiber, F and Webb, JS and Ahrens, CH}, title = {An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {46}, pmid = {33127897}, issn = {2055-5008}, support = {MR/R005621/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Biofilms/classification/*growth & development ; Conserved Sequence ; *Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; *Genes, Essential ; Genomics ; Microfluidic Analytical Techniques ; Mutagenesis, Insertional ; Phenotype ; Proteogenomics ; Pseudomonas aeruginosa/classification/genetics/*physiology ; }, abstract = {Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms.}, } @article {pmid33127888, year = {2020}, author = {Chappell, TC and Nair, NU}, title = {Engineered lactobacilli display anti-biofilm and growth suppressing activities against Pseudomonas aeruginosa.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {48}, pmid = {33127888}, issn = {2055-5008}, support = {DP2 HD091798/HD/NICHD NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Lactobacillus/*metabolism ; Lactobacillus plantarum/metabolism ; Lacticaseibacillus rhamnosus/metabolism ; Metabolic Engineering ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas aeruginosa/drug effects/*physiology ; }, abstract = {Biofilms are an emerging target for new therapeutics in the effort to address the continued increase in resistance and tolerance to traditional antimicrobials. In particular, the distinct nature of the biofilm growth state often means that traditional antimcirobials, developed to combat planktonic cells, are ineffective. Biofilm treatments are designed to both reduce pathogen load at an infection site and decrease the development of resistance by rendering the embedded organisms more susceptible to treatment at lower antimicrobial concentrations. In this work, we developed a new antimicrobial treatment modality using engineered lactic acid bacteria (LAB). We first characterized the natural capacity of two lactobacilli, L. plantarum and L. rhamnosus, to inhibit P. aeruginosa growth, biofilm formation, and biofilm viability, which we found to be dependent upon the low pH generated during culture of the LAB. We further engineered these LAB to secrete enzymes known to degrade P. aeruginosa biofilms and show that our best performing engineered LAB, secreting a pathogen-derived enzyme (PelAh), degrades up to 85% of P. aeruginosa biofilm.}, } @article {pmid33126797, year = {2020}, author = {Etayash, H and Qian, Y and Pletzer, D and Zhang, Q and Xie, J and Cui, R and Dai, C and Ma, P and Qi, F and Liu, R and Hancock, REW}, title = {Host Defense Peptide-Mimicking Amphiphilic β-Peptide Polymer (Bu:DM) Exhibiting Anti-Biofilm, Immunomodulatory, and in Vivo Anti-Infective Activity.}, journal = {Journal of medicinal chemistry}, volume = {63}, number = {21}, pages = {12921-12928}, doi = {10.1021/acs.jmedchem.0c01321}, pmid = {33126797}, issn = {1520-4804}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/chemistry/*pharmacology/therapeutic use ; Antimicrobial Cationic Peptides/*chemistry ; Biofilms/*drug effects ; Cell Survival/drug effects ; Cytokines/pharmacology ; Disease Models, Animal ; Humans ; Immunity, Innate/drug effects ; Leukocytes, Mononuclear/cytology/drug effects/metabolism ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Peptidomimetics ; Polymers/*chemistry/pharmacology/therapeutic use ; Pseudomonas aeruginosa/drug effects/physiology ; Skin Diseases/drug therapy/microbiology/pathology ; }, abstract = {Therapeutic options to treat multidrug resistant bacteria, especially when present in biofilms, are limited due to their high levels of antibiotic resistance. Here, we report the anti-biofilm and immunomodulatory activities of the host defense peptide (HDP)-mimicking β-peptide polymer (20:80 Bu:DM) and investigated its activity in vivo. The polymer outperformed antibiotics in the removal and reduction of the viability of established biofilms, achieving a maximum activity of around 80% reduction in viability. Interestingly the polymer also exhibited HDP-like immunomodulation in inducing chemokines and anti-inflammatory cytokines and suppressing lipopolysaccharide-induced proinflammatory cytokines. When tested in a murine, high-density skin infection model using P. aeruginosa LESB58, the polymer was effective in diminishing abscess size and reducing bacterial load. This study demonstrates the dual functionality of HDP-mimicking β-peptide polymers in inhibiting biofilms and modulating innate immunity, as well as reducing tissue dermonecrosis.}, } @article {pmid33126193, year = {2021}, author = {Ramazanpour Esfahani, A and Batelaan, O and Hutson, JL and Fallowfield, HJ}, title = {Transport and retention of graphene oxide nanoparticles in sandy and carbonaceous aquifer sediments: Effect of physicochemical factors and natural biofilm.}, journal = {Journal of environmental management}, volume = {278}, number = {Pt 1}, pages = {111419}, doi = {10.1016/j.jenvman.2020.111419}, pmid = {33126193}, issn = {1095-8630}, mesh = {Biofilms ; Graphite ; *Groundwater ; *Nanoparticles ; Osmolar Concentration ; Porosity ; Sand ; Silicon Dioxide ; }, abstract = {There is a paucity of information regarding the interaction between GONPs and natural aquifer sediments. Therefore, batch and column experiments were carried out to determine the transport, retention and attachment behavior of GONPs with the surfaces of native aquifer sediments. The experiments were performed with sediments comprising contrasting mineralogical features (sand grains, quartz and limestone sediments), at different temperatures, ionic strength and compositions. Uniquely, this research also investigated the effect of natural biofilm on the retention behavior of nanoparticles in porous media. The retention rate of GONPs at 22 °C was higher than at 4 °C. Moreover, there was greater retention of GONPs onto the surfaces of collectors at higher ionic strengths and cation valence. The retention profiles (RPs) of GONPs in pristine porous media at low ionic strength were linear, which contrasted with hyper-exponential shape of RPs at high ionic strength. The size-distribution analysis of retained GONPs showed decreasing particle diameter with increasing distance from the column inlet at high ionic strength and equal diameter at low ionic strengths. The GONP retention rate was higher for natural porous media than for sand, due to the presence of metal oxides heterogeneities. The presence of biofilm on porous media increased the retention rate of GONPs when compared to the porous media in the absence of biofilm.}, } @article {pmid33125713, year = {2021}, author = {Zhang, C and Wang, C and Jatt, AN and Liu, H and Liu, Y}, title = {Role of RpoS in stress resistance, biofilm formation and quorum sensing of Shewanella baltica.}, journal = {Letters in applied microbiology}, volume = {72}, number = {3}, pages = {307-315}, doi = {10.1111/lam.13424}, pmid = {33125713}, issn = {1472-765X}, support = {ZR2018BC060//Shandong Provincial Natural Science Foundation, China/ ; 2018YYSP009//Key Research and Development of Shandong Province, China/ ; 2019GNC106085//Key Research and Development of Shandong Province, China/ ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Ethanol/pharmacology ; Gene Expression Regulation, Bacterial/genetics ; Hot Temperature ; Hydrogen Peroxide/pharmacology ; Locomotion/genetics ; Quorum Sensing/genetics/*physiology ; Seafood/microbiology ; Shewanella/*genetics/*physiology ; Sigma Factor/*genetics ; Stress, Physiological/genetics ; }, abstract = {Shewanella baltica is one of the most important bacterial species contributing to spoilage of seafood. Principally, RpoS has been recognized as the central regulator of stress resistance in many bacterial species. However, little is known about the role of RpoS in S. baltica. In this study, an rpoS mutant of S. baltica was constructed and analysed for its functions. The results showed that the survival rate of rpoS mutant decreased when treated with heat, ethanol and H2 O2, while increased the resistance to NaCl. Moreover RpoS promoted the biofilm formation of S. baltica at 30°C, while declined at 4°C. Interestingly, the rpoS-deficient mutant showed increased swimming motility. Furthermore, the results revealed that the production of quorum-sensing (QS) signals such as cyclo-(l-Pro-l-Leu) and cyclo-(l-Pro-l-Phe) reduced in rpoS mutant. Mainly, rpoS positively regulated QS response regulators, as the expression of all luxR genes in rpoS mutant significantly decreased relative to wild type. This study reveals that RpoS is a major regulator involved in stress responses, biofilm formation and quorum sensing system in S. baltica. The present work provides significant information for the control of microbiological spoilage of seafood.}, } @article {pmid33124800, year = {2020}, author = {Huang, C and Sun, PP and Won, J and Wang, Y and Boppart, SA and Nguyen, TH}, title = {Effect of Nonphosphorus Corrosion Inhibitors on Biofilm Pore Structure and Mechanical Properties.}, journal = {Environmental science & technology}, volume = {54}, number = {22}, pages = {14716-14724}, pmid = {33124800}, issn = {1520-5851}, support = {R01 EB013723/EB/NIBIB NIH HHS/United States ; R01 EB028615/EB/NIBIB NIH HHS/United States ; }, mesh = {Biofilms ; Corrosion ; *Drinking Water ; *Groundwater ; Silicon Dioxide ; }, abstract = {Understanding the effects of biofilm structural and mechanical properties, which can influence biofilm cohesiveness and detachment under physical stress, is critical for biofilm and biofilm-associated pathogen control. In this study, we used optical coherence tomography (OCT) and nanoindentation to determine the role of silicate and tin (two experimental nonphosphate corrosion inhibitors) on the porous structure and stiffness of three types of multispecies biofilms. These biofilms were grown from groundwater (a drinking water source), and this groundwater was amended with either tin or silicate corrosion inhibitor (0.5 mg/L as Sn and 20 mg/L as SiO2). Based on the elastic moduli of these biofilms, tin biofilms and groundwater biofilms were the stiffest, followed by silicate biofilms. The thickness normalized by the growth time for silicate biofilms was highest at 38 ± 7.1 μm/month, compared to 21 ± 3.2 and 11 ± 2.4 μm/month for tin biofilms and groundwater biofilms, respectively. The silicate biofilms had the greatest overall porosities and were thickest among the three biofilms. Based on the pore network modeling (PNM) of OCT images, larger pores and connections were found in the silicate biofilms compared to those in tin and groundwater biofilms. Our analysis showed that the thicker and more porous biofilms (silicate biofilms) were potentially less resistant to deformation than the thinner and denser biofilms (tin and groundwater biofilms).}, } @article {pmid33124343, year = {2020}, author = {Li, R and Yu, LF and Zhang, XX and Dai, ZC and Hua, SS and Peng, DC}, title = {[Adaptability of Nitrifying Biofilm Systems to Low Temperature: MBBR and IFAS].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {41}, number = {8}, pages = {3691-3698}, doi = {10.13227/j.hjkx.201911234}, pmid = {33124343}, issn = {0250-3301}, mesh = {*Biofilms ; Bioreactors ; Nitrification ; *Sewage ; Temperature ; }, abstract = {The long-term effects of a decreasing temperature on the nitrification performance, biofilm characteristics, and nitrifier community in a moving-bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) system were investigated at various temperatures (20, 15, and 10℃) to explore the adaptability of nitrifying biofilm systems to low temperatures. During the experiment, the extracellular polymeric substances (EPS) in the biofilms increased with decreasing temperature, which resulted in an increased biofilm mass and thickness. As there was only a biofilm phase in the MBBR to remove ammonia, the part of the carriers in the MBBR at 10℃ became plugged, which partially led to a deterioration in the effluent water quality. This indicated that the IFAS system was more adaptable to low temperatures than was the MBBR. Meanwhile, the results for the nitrifier activities showed that, although the nitrification contribution rate of the suspended phase in the IFAS system always dominated during the experiment, that of the fixed phase with regards to the ammonia uptake rate (AUR) gradually increased from 30.72% at 20℃ to 39.85% at 10℃. This indicated that the biofilm played an enhanced role in nitrification in the IFAS system. Moreover, the qPCR results revealed that the nitrifier copies of the number of biofilms increased slightly with decreased temperature, and coincided with an increase in biomass, which partially compensated for the decreased nitrification activity. These findings provide a theoretical basis for the application of the biofilm systems to wastewater treatment.}, } @article {pmid33124342, year = {2020}, author = {Jiang, YQ and Li, JH and Fang, ZG}, title = {[Effect of Porous Fillers Properties on Biofilm Growth].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {41}, number = {8}, pages = {3684-3690}, doi = {10.13227/j.hjkx.201912226}, pmid = {33124342}, issn = {0250-3301}, mesh = {*Biofilms ; Porosity ; *Sewage ; Wastewater ; }, abstract = {As an important part of biological aerated filters (BAFs), porous fillers are key to the effectiveness of BAF wastewater treatment. At present, there are many types of fillers, but the influence of the surface physical and chemical properties on biofilm formation is unclear, and how to compare and select the best biological filler remains a difficult problem in BAF engineering applications. In this study, the physical and chemical characteristics of several porous biological fillers that are commonly used in BAFs were studied, and the correlation between their physical/chemical properties and the biofilm attachment and enzyme activity of the biofilm on the filler was investigated. The results showed that the sponge filler could easily absorb sludge, but also clogged easily and the overall biofilm activity was not high. The three-dimensional hollow filler had a low surface-adsorbed biomass, but the specific surface area was large and the surface attachment growth biofilm activity was relatively strong. Ceramsite had a good hydrophilicity and high surface roughness, and the zeta potential was the most positive. Moreover, microorganisms easily attached and grew, it had the strongest sludge adhesion performance, and the best biofilm activity. According to a redundancy analysis (RDA), the main factor affecting the biomass on the surface of the fillers was the zeta potential, whereas the main factors affecting the surface sludge activity of the fillers was the clearance rate. According to the removal load of NH4[+]-N by six groups of reactors, the removal load of NH4[+]-N by ceramsite was the largest [68 g·(m[3]·d)[-1]], and was followed by volcanic rocks [67 g·(m[3]·d)[-1]]. Combined with the above factors, ceramsite was determined to be the most suitable filler for BAF.}, } @article {pmid33124148, year = {2021}, author = {Zhao, W and Vermace, RR and Mattes, TE and Just, C}, title = {Impacts of ammonia loading and biofilm age on the prevalence of nitrogen-cycling microorganisms in a full-scale submerged attached-growth reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {5}, pages = {787-796}, doi = {10.1002/wer.1471}, pmid = {33124148}, issn = {1554-7531}, support = {//University of Iowa/ ; }, mesh = {*Ammonia ; Anaerobiosis ; Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; Prevalence ; Wastewater ; }, abstract = {This study reports the impacts of seasonal ammonia load changes and biofilm age on the quantity of biomass and on the prevalence of ammonia- and nitrite-metabolizing organisms within a submerged attached-growth reactor (SAGR™) following lagoon treatment. Ammonia (NH3) loadings (0.12-3.17 kg/d) in the primary SAGR were measured over 223 days from May to December in 2017. Adjustment of the wastewater flow path on September 1 successfully increased NH3 loading to the primary SAGR, which subsequently caused reactor biomass to increase. The NH3 removal rate in October (0.5 kg/d) was greater than rates in June and July (0.3 and 0.2 kg/d) despite a water temperature decrease from >24 to 15.6°C. This elevated removal rate in October, and the sustained removal rate in December (0.4 kg/d, 5.3°C) were associated with a measured increase in microbial biomass. The relative abundance of the anammox organism C. Brocadia was 5 times greater in the mature biofilm after 686 days of growth, and the genus Pseudomonas increased sevenfold. The presence of Pseudomonas, which contains denitrifying species, and anammox suggests a high potential for removal of total nitrogen in SAGRs. PRACTITIONER POINTS: Pseudomonas prevalence and the presence of anammox suggest a high potential for total nitrogen removal in mature SAGR biofilms. The abundance of the anammox microorganism C. Brocadia was greater after 686 days of biofilm growth compared with 33 days. Simple operational changes can increase biomass in the SAGR to maintain, or even increase, NH3 transformation rates during cold weather.}, } @article {pmid33123497, year = {2020}, author = {Roisin, L and Melloul, E and Woerther, PL and Royer, G and Decousser, JW and Guillot, J and Dannaoui, E and Botterel, F}, title = {Modulated Response of Aspergillus fumigatus and Stenotrophomonas maltophilia to Antimicrobial Agents in Polymicrobial Biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {574028}, pmid = {33123497}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Antifungal Agents/pharmacology ; Aspergillus fumigatus ; Biofilms ; Humans ; Microbial Sensitivity Tests ; *Stenotrophomonas maltophilia ; }, abstract = {Introduction: The complexity of biofilms constitutes a therapeutic challenge and the antimicrobial susceptibility of fungal-bacterial biofilms remains poorly studied. The filamentous fungus Aspergillus fumigatus (Af) and the Gram-negative bacillus Stenotrophomonas maltophilia (Sm) can form biofilms and can be co-isolated from the airways of cystic fibrosis (CF) patients. We previously developed an in vitro biofilm model which highlighted the antibiosis effect of Sm on Af, which was dependent on the bacterial fitness. The aim of the present study was to investigate the in vitro susceptibility of Af and Sm in mono- or polymicrobial biofilms to five antimicrobial agents alone and in two-drug combinations. Methods: Af and Sm clinical reference strains and two strains from CF sputa were tested through a planktonic and biofilm approaches. Af, Sm, or Af-Sm susceptibilities to amphotericin B (AMB), itraconazole (ITC), voriconazole (VRC), levofloxacin (LVX), and rifampicin (RFN) were evaluated by conventional planktonic techniques, crystal violet, XTT, qPCR, and viable plate count. Results: Af planktonic cells and biofilms in formation were more susceptible to AMB, ITC, and VRC than Af mature biofilms. Af mature biofilms were susceptible to AMB, but not to ITC and VRC. Based on viable plate count, a lower concentration of LVX and RFN was required to reduce Sm cell numbers on biofilms in formation compared with mature biofilms. The antibiosis effect of Sm on Af growth was more pronounced for the association of CF strains that exhibited a higher fitness than the reference strains. In Af-Sm biofilms, the fungal susceptibility to AMB was increased compared with Af biofilms. In contrast, the bacterial susceptibility to LVX decreased in Af-Sm biofilms and was fungal biomass-dependent. The combination of AMB (64 μg/mL) with LVX or RFN (4 μg/mL) was efficient to impair Af and Sm growth in the polymicrobial biofilm. Conclusion: Sm increased the Af susceptibility to AMB, whereas Af protected Sm from LVX. Interactions between Af and Sm within biofilms modulate susceptibility to antimicrobial agents, opening the way to new antimicrobial strategies in CF patients.}, } @article {pmid33123112, year = {2020}, author = {Oliveira, VC and Bim, FL and Monteiro, RM and Macedo, AP and Santos, ES and Silva-Lovato, CH and Paranhos, HFO and Melo, LDR and Santos, SB and Watanabe, E}, title = {Identification and Characterization of New Bacteriophages to Control Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Endotracheal Tubes.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {580779}, pmid = {33123112}, issn = {1664-302X}, abstract = {Studies involving antimicrobial-coated endotracheal tubes are scarce, and new approaches to control multidrug-resistant Pseudomonas aeruginosa biofilm on these devices should be investigated. In this study, five new P. aeruginosa bacteriophages from domestic sewage were isolated. All of them belong to the order Caudovirales, Myoviridae family. They are pH and heat stable and produce 27 to 46 particles after a latent period of 30 min at 37°C. Their dsDNA genome (ranging from ∼62 to ∼65 kb) encodes 65 to 89 different putative proteins. They exhibit a broad lytic spectrum and infect 69.7% of the P. aeruginosa strains tested. All the bacteriophages were able to reduce the growth of P. aeruginosa strains in planktonic form. The bacteriophages were also able to reduce the biofilm viability rates and the metabolic activity of P. aeruginosa strains in a model of biofilms associated with endotracheal tubes. In addition, scanning electron microscopy micrographs showed disrupted biofilms and cell debris after treatment of bacteriophages, revealing remarkable biofilm reduction. The lytic activity on multidrug-resistant P. aeruginosa biofilm indicates that the isolated bacteriophages might be considered as good candidates for therapeutic studies and for the application of bacteriophage-encoded products.}, } @article {pmid33120233, year = {2021}, author = {Merkl, P and Aschtgen, MS and Henriques-Normark, B and Sotiriou, GA}, title = {Biofilm interfacial acidity evaluation by pH-Responsive luminescent nanoparticle films.}, journal = {Biosensors & bioelectronics}, volume = {171}, number = {}, pages = {112732}, pmid = {33120233}, issn = {1873-4235}, support = {758705/ERC_/European Research Council/International ; }, mesh = {Biofilms ; *Biosensing Techniques ; Hydrogen-Ion Concentration ; Luminescence ; *Nanoparticles ; }, abstract = {Biofilms are dense bacterial colonies that may adhere to the surfaces of medical devices and are major contributors to infections. These colonies are characterized by a self-produced matrix of extracellular polymeric substances (EPS). Bacterial biofilms are difficult to treat with the commonly used antibiotics partially because of their poor diffusion through the EPS and therefore require new targeted strategies to effectively fight them. Biofilms may produce an acidic microenvironment which can be exploited to design such targeted treatment strategies. However, there is currently a lack of high-throughput ways to determine the acidity of biofilms at their interface with the medical device. Here, a novel all-inorganic pH responsive system is developed from luminescent carbonated hydroxyapatite nanoparticles doped with Eu[3+] ions which can determine the biofilm acidity fluorometrically due to carbonate removal in acidic environments that directly affects the nanoparticle luminescence. The pH responsive nanoparticles are in-situ deposited during their production onto substrates on which a variety of clinically-relevant biofilms are grown. The acidity of their interfacial (micro)environment depends on the bacterial species and strain even when differences in biofilm biomass are considered.}, } @article {pmid33117092, year = {2020}, author = {Qasim, N and Shahid, M and Yousaf, F and Riaz, M and Anjum, F and Faryad, MA and Shabbir, R}, title = {Therapeutic Potential of Selected Varieties of Phoenix Dactylifera L. Against Microbial Biofilm and Free Radical Damage to DNA.}, journal = {Dose-response : a publication of International Hormesis Society}, volume = {18}, number = {4}, pages = {1559325820962609}, pmid = {33117092}, issn = {1559-3258}, abstract = {Phoenix dactylifera L. (Date palm) is the most widely consumed fruit around the world and is rich source of nutrients containing dietary fibers, minerals, vitamins, sugar, protein and antioxidants with potent bioactivities against various microbial pathogens. This study evaluated the therapeutic potential of 2 varieties of ethanolic extracts of Phoenix dactylifera i-e Ajwa and Khalas against bacterial biofilms. This study also investigated the protective effect of Ajwa and Khalas against hydroxyl radical damage to calf thymus DNA. Antioxidant potential through different antioxidant assays showed that Ajwa has higher antioxidant potential than Khalas. Both Ajwa and Khalas presented good antimicrobial activities against Bacillus subtilis and Pasteurella multocida. Biofilm inhibition assay showed that increasing concentration of Ajwa and Khalas exhibited higher percentage of bacterial biofilm inhibition. Microscopic examination revealed significant inhibition of microbial biofilm. Ajwa and Khalas protected the calf thymus DNA against damage caused by hydroxyl radicals produced by fenton reagent. Fourier Transform Infrared (FTIR) spectra confirmed the presence of O-H, C=C and C-O functional groups in tested extracts. The study concluded that tested varieties of Date palm have the potential to inhibit bacterial biofilms and can be used for therapeutic purposes against biofilm producing pathogens.}, } @article {pmid33116164, year = {2020}, author = {Di Giulio, M and Di Lodovico, S and Fontana, A and Traini, T and Di Campli, E and Pilato, S and D'Ercole, S and Cellini, L}, title = {Graphene Oxide affects Staphylococcus aureus and Pseudomonas aeruginosa dual species biofilm in Lubbock Chronic Wound Biofilm model.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {18525}, pmid = {33116164}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Graphite/metabolism/*pharmacology ; Microbial Sensitivity Tests ; Models, Biological ; Pseudomonas aeruginosa/drug effects/metabolism ; Staphylococcus aureus/drug effects/metabolism ; Wound Healing/*drug effects/physiology ; }, abstract = {Chronic wound management becomes a complex procedure because of the persistence of forming biofilm pathogens that do not respond to antimicrobial treatment. The aim of this paper is to detect the Graphene Oxide-GO effect on Staphylococcus aureus and Pseudomonas aeruginosa dual species wound biofilm in Lubbock Chronic Wound Biofilm-LCWB model. LCWB is a recognized model that mimics the spatial microbial colonization into chronic wounds and reproduces the wound and its clot. Staphylococcus aureus PECHA 10 and P. aeruginosa PECHA 4, are the pathogens used in the study. The GO effect on both in forming and mature biofilms, is detected by the evaluation of the CFU/mg reduction, the cell viability and ultrastructural analysis of the treated LCWBs. Graphene Oxide, at 50 mg/l, shows a significant antibiofilm effect in forming and mature LCWBs. In particular, during the biofilm formation, GO reduces the S. aureus and P. aeruginosa growth of 55.05% ± 4.73 and 44.18% ± 3.91 compared to the control. In mature biofilm, GO affects S. aureus and P. aeruginosa by reducing their growth of 70.24% ± 4.47 and 63.68% ± 17.56, respectively. Images taken by SEM show that GO display a disaggregated microbial effect also disrupting the fibrin network of the wound-like biofilm framework. In conclusion, GO used against microorganisms grown in LCWB, displays a significant inhibitory action resulting in a promising tool for potential application in wound management.}, } @article {pmid33116127, year = {2020}, author = {Heumann, A and Assifaoui, A and Da Silva Barreira, D and Thomas, C and Briandet, R and Laurent, J and Beney, L and Lapaquette, P and Guzzo, J and Rieu, A}, title = {Intestinal release of biofilm-like microcolonies encased in calcium-pectinate beads increases probiotic properties of Lacticaseibacillus paracasei.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {44}, pmid = {33116127}, issn = {2055-5008}, mesh = {Animals ; Biofilms/*growth & development ; Capsules ; Colitis/chemically induced/*diet therapy ; Dextran Sulfate/adverse effects ; Disease Models, Animal ; Drug Compounding ; Extracellular Polymeric Substance Matrix/metabolism ; Freeze Drying ; Lacticaseibacillus paracasei/*physiology ; Male ; Mice ; Osmotic Pressure ; Pectins/*chemistry ; Probiotics/*administration & dosage/pharmacology ; Treatment Outcome ; }, abstract = {In this study, we show that calcium pectinate beads (CPB) allow the formation of 20 µm spherical microcolonies of the probiotic bacteria Lacticaseibacillus paracasei (formerly designated as Lactobacillus paracasei) ATCC334 with a high cell density, reaching more than 10 log (CFU/g). The bacteria within these microcolonies are well structured and adhere to a three-dimensional network made of calcium-pectinate through the synthesis of extracellular polymeric substances (EPS) and thus display a biofilm-like phenotype, an attractive property for their use as probiotics. During bacterial development in the CPB, a coalescence phenomenon arises between neighboring microcolonies accompanied by their peripheral spatialization within the bead. Moreover, the cells of L. paracasei ATCC334 encased in these pectinate beads exhibit increased resistance to acidic stress (pH 1.5), osmotic stress (4.5 M NaCl), the freeze-drying process and combined stresses, simulating the harsh conditions encountered in the gastrointestinal (GI) tract. In vivo, the oral administration of CPB-formulated L. paracasei ATCC334 in mice demonstrated that biofilm-like microcolonies are successfully released from the CPB matrix in the colonic environment. In addition, these CPB-formulated probiotic bacteria display the ability to reduce the severity of a DSS-induced colitis mouse model, with a decrease in colonic mucosal injuries, less inflammation, and reduced weight loss compared to DSS control mice. To conclude, this work paves the way for a new form of probiotic administration in the form of biofilm-like microcolonies with enhanced functionalities.}, } @article {pmid33114511, year = {2020}, author = {Jabłońska-Wawrzycka, A and Rogala, P and Czerwonka, G and Michałkiewicz, S and Hodorowicz, M and Kowalczyk, P}, title = {Ruthenium(IV) Complexes as Potential Inhibitors of Bacterial Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {21}, pages = {}, pmid = {33114511}, issn = {1420-3049}, support = {Project miniGrant UJK No. SMGR.RN .20.262.656 and SMGR.RN .20.109.604//Ministerstwo Nauki i Szkolnictwa Wyższego/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacteria/*drug effects/genetics/growth & development/metabolism ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects/*growth & development ; Coordination Complexes/*chemistry/*pharmacology ; DNA Damage/drug effects ; DNA Glycosylases/antagonists & inhibitors ; Electrochemistry ; Models, Molecular ; Molecular Conformation ; Ruthenium/*chemistry ; }, abstract = {With increasing antimicrobial resistance there is an urgent need for new strategies to control harmful biofilms. In this study, we have investigated the possibility of utilizing ruthenium(IV) complexes (H3O)2(HL1)2[RuCl6]·2Cl·2EtOH (1) and [RuCl4(CH3CN)2](L[3]2)·H2O (2) (where L1-2-hydroxymethylbenzimadazole, L[3]2-1,4-dihydroquinoxaline-2,3-dione) as effective inhibitors for biofilms formation. The biological activities of the compounds were explored using E. coli, S. aureus, P. aeruginosa PAO1, and P. aeruginosa LES B58. The new chloride ruthenium complexes were characterized by single-crystal X-ray diffraction analysis, Hirshfeld surface analysis, FT-IR, UV-Vis, magnetic and electrochemical (CV, DPV) measurements, and solution conductivity. In the obtained complexes, the ruthenium(IV) ions possess an octahedral environment. The intermolecular classical and rare weak hydrogen bonds, and π···π stacking interactions significantly contribute to structure stabilization, leading to the formation of a supramolecular assembly. The microbiological tests have shown complex 1 exhibited a slightly higher anti-biofilm activity than that of compound 2. Interestingly, electrochemical studies have allowed us to determine the relationship between the oxidizing properties of complexes and their biological activity. Probably the mechanism of action of 1 and 2 is associated with generating a cellular response similar to oxidative stress in bacterial cells.}, } @article {pmid33114489, year = {2020}, author = {Lim, BS and Kim, BH and Shon, WJ and Ahn, SJ}, title = {Effects of Caries Activity on Compositions of Mutans Streptococci in Saliva-Induced Biofilm Formed on Bracket Materials.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {21}, pages = {}, pmid = {33114489}, issn = {1996-1944}, support = {20001155//the Ministry of Trade, Industry & Energy/ ; }, abstract = {This study aimed to investigate effects of caries activity on composition of mutans streptococci in saliva-induced biofilms formed on bracket materials. Three bracket materials were used as specimens: ceramic, metal, and plastic. After saliva was collected using a spitting method from caries-active (CA, decayed, missing, filled teeth (DMFT) score ≥ 10) and caries-free (CF, DMFT score = 0) subjects, saliva was mixed with growth media in a proportion of 1:10. The saliva solution was then incubated with each bracket material. After a saliva-induced biofilm was developed on the surface of the bracket material, the amounts of total bacteria and mutans streptococci were determined using real-time polymerase chain reaction. The results showed that biofilms from CA saliva contained more mutans streptococci but less total bacteria than biofilms from CF saliva, regardless of material type. Adhesion of total bacteria to ceramic was higher than to plastic, regardless of caries activity. Mutans streptococci adhered more to ceramic than to metal and plastic in both biofilms from CA and CF saliva, but there was a difference in adhesion between Streptococcus mutans and Streptococcus sobrinus. The amount of S. mutans was higher than that of S. sobrinus in biofilms from CA saliva despite similar amounts of the two strains in biofilms from CF saliva. The stronger adhesion of S. mutans to ceramic than to metal and plastic was more evident in biofilms from CA saliva than in biofilms from CF saliva. This study suggests that caries activity and material type significantly influenced composition of mutans streptococci in biofilms formed on bracket materials.}, } @article {pmid33113846, year = {2020}, author = {Stirpe, M and Brugnoli, B and Donelli, G and Francolini, I and Vuotto, C}, title = {Poloxamer 338 Affects Cell Adhesion and Biofilm Formation in Escherichia coli: Potential Applications in the Management of Catheter-Associated Urinary Tract Infections.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33113846}, issn = {2076-0817}, support = {HBMS//Hutchison Biofilm Medical Solutions Limited/ ; RP11715C785E4434//Sapienza Università di Roma/ ; }, abstract = {Poloxamers are nontoxic, amphiphilic copolymers used in different formulations. Due to its surfactant properties, Poloxamer 338 (P388) is herein proposed as a strategy to avoid biofilm formation often causing recalcitrant catheter-associated urinary tract infections (CAUTI). The aim is to evaluate the ability of P388 coatings to affect the adhesion of Ec5FSL and Ec9FSL Escherichia coli strains on silicone urinary catheters. Attenuated total reflection infrared spectroscopy, atomic force microscopy, and static water contact angle measurement were employed to characterize the P388-coated silicone catheter in terms of amount of P388 layered, coating thickness, homogeneity, and hydrophilicity. In static conditions, the antifouling power of P388 was defined by comparing the E. coli cells adherent on a hydrophilic P388-adsorbed catheter segment with those on an uncoated one. A P388-coated catheter, having a homogeneous coverage of 35 nm in thickness, reduced of 0.83 log10 and 0.51 log10 the biofilm of Ec5FSL and Ec9FSL, respectively. In dynamic conditions, the percentage of cell adhesion on P388-adsorbed silicone channels was investigated by a microfluidic system, simulating the in vivo conditions of catheterized patients. As a result, both E. coli isolates were undetected. The strong and stable antifouling property against E. coli biofilm lead us to consider P388 as a promising anti-biofilm agent for CAUTIs control.}, } @article {pmid33113538, year = {2021}, author = {Blicharz, L and Michalak, M and Szymanek-Majchrzak, K and Młynarczyk, G and Skowroński, K and Rudnicka, L and Samochocki, Z}, title = {The Propensity to Form Biofilm in vitro by Staphylococcus aureus Strains Isolated from the Anterior Nares of Patients with Atopic Dermatitis: Clinical Associations.}, journal = {Dermatology (Basel, Switzerland)}, volume = {237}, number = {4}, pages = {528-534}, doi = {10.1159/000511182}, pmid = {33113538}, issn = {1421-9832}, mesh = {Adolescent ; Adult ; Aged ; *Biofilms ; Dermatitis, Atopic/*microbiology ; Female ; Humans ; In Vitro Techniques ; Male ; Middle Aged ; Nasal Cavity/*microbiology ; Severity of Illness Index ; Skin/microbiology ; Staphylococcus aureus/*isolation & purification ; Young Adult ; }, abstract = {BACKGROUND: Atopic dermatitis is a chronic inflammatory dermatosis with complex pathogenesis. The skin microbiome in atopic dermatitis is dominated by Staphylococcus aureus which shows the ability to produce biofilm.

OBJECTIVES: The aim of this work was to assess the influence of S. aureus biofilm on the course of atopic dermatitis.

METHODS: Disease severity was evaluated based on the SCORAD index in 56 adult patients with atopic dermatitis. Microtiter plate assay of the propensity to form biofilm was performed on S. aureus strains isolated from the anterior nares, lesional skin, and nonlesional skin. Microbiological results were correlated to the clinical parameters and total IgE concentration.

RESULTS: Biofilm-producing strains of S. aureus were identified in 76.3% (29/38) and 79.1% (34/43) of samples from the anterior nares and lesional skin, respectively (p > 0.05), and in 48.5% (16/33) of samples from nonlesional skin (p < 0.03). Patients colonized by biofilm-producing strains of S. aureus within the anterior nares showed statistically higher mean values of total and objective SCORAD and its components (extent, dryness), and of the largest extent of skin lesions during the flares in the last year when compared to patients colonized by non-biofilm-producing strains. Carriage of biofilm-producing S. aureus on lesional skin was associated with higher mean values of the extent of skin lesions during stable periods of the disease.

CONCLUSIONS: The results of this study may suggest a relationship between the production of biofilm by S. aureus strains colonizing the anterior nares and the course of atopic dermatitis. Biofilm seems crucial for dispersal and persistent colonization of large areas of the skin by this pathogen. Destruction of S. aureus biofilm could positively affect the course of atopic dermatitis.}, } @article {pmid33111915, year = {2020}, author = {Rodrigues, RL and Lima, JLDC and Sena, KXDFR and Maciel, MAV}, title = {Phenotypic and genotypic analysis of biofilm production by Pseudomonas aeruginosa isolates from infection and colonization samples.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {53}, number = {}, pages = {e20200399}, pmid = {33111915}, issn = {1678-9849}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Genotype ; Humans ; Phenotype ; *Pseudomonas Infections ; *Pseudomonas aeruginosa/genetics ; Quorum Sensing/drug effects ; Virulence/genetics ; Virulence Factors ; }, abstract = {INTRODUCTION: Pseudomonas aeruginosa is an opportunistic pathogen associated with healthcare-related infections, affecting mainly patients with underlying diseases and immunosuppression. This microorganism has several virulence mechanisms that favour its pathogenesis, including the production of biofilm. This study aimed to analyze the phenotypic production of biofilms, the occurrence of quorum sensing (QS) genes, and the clonal profile of clinical isolates of P. aeruginosa from colonized/infected patients in a tertiary hospital in Recife-PE.

METHODS: We obtained 21 isolates that were classified as infection isolates (II), and 10 colonization isolates (CI). The phenotypic analysis for biofilm production was performed quantitatively. The QS genes were detected by specific PCRs, and the clonal profile was assessed using ERIC-PCR.

RESULTS: Of the 31 isolates, 58.1 % (18/31) were biofilm producers, of which 70 % (7/10) were CI and classified as weakly adherent; 52.4 % (11/21) of the II produced biofilms, and were classified as weak (38.1 %, (8/21)), moderate (9.5 %, (2/21)), and strongly adherent (4.8 %, (1/21)). All isolates harbored the QS genes analyzed. In the clonal analysis, 26 distinct genetic profiles were identified, highlighting the presence of a clone in four samples, i.e., one infection isolate, and 3 colonization isolates.

CONCLUSIONS: The detection of biofilm formation is important in P. aeruginosa in addition to the identification of colonization and infection isolates, especially from complex environments such as ICUs. Further, we define a strategy for monitoring and analyzing P. aeruginosa strains that can potentially cause infections in hospitalized patients.}, } @article {pmid33111157, year = {2020}, author = {Sterzenbach, T and Helbig, R and Hannig, C and Hannig, M}, title = {Bioadhesion in the oral cavity and approaches for biofilm management by surface modifications.}, journal = {Clinical oral investigations}, volume = {24}, number = {12}, pages = {4237-4260}, pmid = {33111157}, issn = {1436-3771}, support = {HE 7149/3-1//Deutsche Forschungsgemeinschaft/ ; }, mesh = {*Bacterial Adhesion ; *Biofilms ; Dental Pellicle ; Mouth ; Surface Properties ; }, abstract = {BACKGROUND: All soft and solid surface structures in the oral cavity are covered by the acquired pellicle followed by bacterial colonization. This applies for natural structures as well as for restorative or prosthetic materials; the adherent bacterial biofilm is associated among others with the development of caries, periodontal diseases, peri-implantitis, or denture-associated stomatitis. Accordingly, there is a considerable demand for novel materials and coatings that limit and modulate bacterial attachment and/or propagation of microorganisms.

OBJECTIVES AND FINDINGS: The present paper depicts the current knowledge on the impact of different physicochemical surface characteristics on bioadsorption in the oral cavity. Furthermore, it was carved out which strategies were developed in dental research and general surface science to inhibit bacterial colonization and to delay biofilm formation by low-fouling or "easy-to-clean" surfaces. These include the modulation of physicochemical properties such as periodic topographies, roughness, surface free energy, or hardness. In recent years, a large emphasis was laid on micro- and nanostructured surfaces and on liquid repellent superhydrophic as well as superhydrophilic interfaces. Materials incorporating mobile or bound nanoparticles promoting bacteriostatic or bacteriotoxic properties were also used. Recently, chemically textured interfaces gained increasing interest and could represent promising solutions for innovative antibioadhesion interfaces. Due to the unique conditions in the oral cavity, mainly in vivo or in situ studies were considered in the review.

CONCLUSION: Despite many promising approaches for modulation of biofilm formation in the oral cavity, the ubiquitous phenomenon of bioadsorption and adhesion pellicle formation in the challenging oral milieu masks surface properties and therewith hampers low-fouling strategies.

CLINICAL RELEVANCE: Improved dental materials and surface coatings with easy-to-clean properties have the potential to improve oral health, but extensive and systematic research is required in this field to develop biocompatible and effective substances.}, } @article {pmid33109020, year = {2020}, author = {Stricker, L and Guido, I and Breithaupt, T and Mazza, MG and Vollmer, J}, title = {Hybrid sideways/longitudinal swimming in the monoflagellate Shewanella oneidensis: from aerotactic band to biofilm.}, journal = {Journal of the Royal Society, Interface}, volume = {17}, number = {171}, pages = {20200559}, pmid = {33109020}, issn = {1742-5662}, mesh = {Biofilms ; Chemotaxis ; *Shewanella ; *Swimming ; }, abstract = {Shewanella oneidensis MR-1 are facultative aerobic electroactive bacteria with an appealing potential for sustainable energy production and bioremediation. They gather around air sources, forming aerotactic bands and biofilms. Here, we experimentally follow the evolution of the band around an air bubble, and we find good agreement with the numerical solutions of the pertinent transport equations. Video microscopy reveals a transition between motile and non-motile MR-1 upon oxygen depletion, preventing further development of the biofilm. We discover that MR-1 can alternate between longitudinal fast and sideways slow swimming. The resulting bimodal velocity distributions change in response to different oxygen concentrations and gradients, supporting the biological functions of aerotaxis and confinement.}, } @article {pmid33108702, year = {2021}, author = {Sharapova, Y and Švedas, V and Suplatov, D}, title = {Catalytic and lectin domains in neuraminidase A from Streptococcus pneumoniae are capable of an intermolecular assembly: Implications for biofilm formation.}, journal = {The FEBS journal}, volume = {288}, number = {10}, pages = {3217-3230}, doi = {10.1111/febs.15610}, pmid = {33108702}, issn = {1742-4658}, support = {15-14-00069-P//Russian Science Foundation/ ; }, mesh = {Amino Acid Sequence ; Anti-Bacterial Agents/*chemistry/pharmacology ; Bacterial Proteins/antagonists & inhibitors/*chemistry/genetics/metabolism ; Biofilms/drug effects/growth & development ; Catalytic Domain ; Computational Biology/methods ; Gene Expression ; Glycosides/*chemistry/metabolism ; Hydrogen Bonding ; Kinetics ; Mannose-Binding Lectins/*chemistry/pharmacology ; Models, Molecular ; Neuraminidase/antagonists & inhibitors/*chemistry/genetics/metabolism ; Plant Lectins/*chemistry/pharmacology ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Sequence Alignment ; Sequence Homology, Amino Acid ; Streptococcus pneumoniae/drug effects/*enzymology/growth & development ; Substrate Specificity ; Thermodynamics ; }, abstract = {Neuraminidase A from Streptococcus pneumoniae (NanA) is a cell wall-bound modular enzyme containing one lectin and one catalytic domain. Unlike homologous NanB and NanC expressed by the same bacterium, the two domains within one NanA molecule do not form a stable interaction and are spatially separated by a 16-amino acid-long flexible linker. In this work, the ability of NanA to form intermolecular assemblies was characterized using the methods of molecular modeling and bioinformatic analysis based on crystallographic data and by bringing together previously published experimental data. It was concluded that two catalytic domains, as well as one catalytic and one lectin domain, originating from two cell wall-bound NanA molecules, can interact through a previously uncharacterized interdomain interface to form complexes stabilized by a network of intermolecular hydrogen bonds and salt bridges. Supercomputer modeling strongly indicated that artocarpin, an earlier experimentally discovered inhibitor of the pneumococcal biofilm formation, is able to bind to a site located in the catalytic domain of one NanA entity and prevent its interaction with the lectin or catalytic domain of another NanA entity, thus directly precluding the generation of intermolecular assemblies. The revealed structural adaptation is discussed as one plausible mechanism of noncatalytic participation of this potentially key pathogenicity enzyme in pneumococcal biofilm formation.}, } @article {pmid33108462, year = {2021}, author = {Wang, R and Zhou, Y and Kalchayanand, N and Harhay, DM and Wheeler, TL}, title = {Consecutive Treatments with a Multicomponent Sanitizer Inactivate Biofilms Formed by Escherichia coli O157:H7 and Salmonella enterica and Remove Biofilm Matrix.}, journal = {Journal of food protection}, volume = {84}, number = {3}, pages = {408-417}, doi = {10.4315/JFP-20-321}, pmid = {33108462}, issn = {1944-9097}, mesh = {Biofilms ; Colony Count, Microbial ; *Escherichia coli O157 ; Extracellular Polymeric Substance Matrix ; Food Microbiology ; *Salmonella enterica ; }, abstract = {ABSTRACT: Many foodborne pathogens, including Escherichia coli O157:H7 and Salmonella enterica, can develop biofilms on contact surfaces at meat processing plants. Owing to the high tolerance of the biofilm cells associated with the three-dimensional biofilm structure and the well-expressed bacterial extracellular polymeric substances, it is a real challenge to completely inactivate and remove mature biofilms, as well as further prevent biofilm reoccurrence and pathogen survival. In the present study, we evaluated the effectiveness of consecutive treatments (10 to 120 min per treatment) by repeatedly applying a multicomponent sanitizer, based on a functional mechanism by synergistic combination of hydrogen peroxide and quaternary ammonia compounds, against biofilms formed by E. coli O157:H7 and S. enterica strains. Biofilms on stainless steel surfaces were treated with 2.5, 5, or 10% (recommended working concentration) of the sanitizer applied as a foam or liquid solution. Our results showed that the multicomponent sanitizer significantly (P < 0.05) reduced the amount of viable biofilm cells at all concentrations, as enumerable bacteria were only detected after low-concentration treatments (2.5 or 5%) with short exposure periods (10 or 20 min per treatment). Treatments with high concentrations (5 or 10%) of the sanitizer, multiple consecutive treatments (2 or 3 treatments), and sufficient exposure time (>60 min per treatment) effectively controlled pathogen survival postsanitization. Examination with a scanning electron microscope showed that treatment with the sanitizer at 5% strength significantly dissolved the connecting extracellular polysaccharide matrix and removed the majority of the biofilm matrix. No intact biofilm structure was detected after the 10% sanitizer treatment; instead, scattered individual bacteria with visibly altered cell morphology were observed. The treated bacteria exhibited indented and distorted shapes with shortened cell length and increased surface roughness, indicating severe cell injury and death. Our observations indicated that consecutive treatments with the multicomponent sanitizer was effective in inactivating E. coli O157:H7 and S. enterica biofilms and preventing pathogen reoccurrence.}, } @article {pmid33108154, year = {2020}, author = {Xu, M and Hu, Y and Xiao, Y and Zhang, Y and Sun, K and Wu, T and Lv, N and Wang, W and Ding, W and Li, F and Qiu, B and Li, J}, title = {Near-Infrared-Controlled Nanoplatform Exploiting Photothermal Promotion of Peroxidase-like and OXD-like Activities for Potent Antibacterial and Anti-biofilm Therapies.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {45}, pages = {50260-50274}, doi = {10.1021/acsami.0c14451}, pmid = {33108154}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Escherichia coli/*drug effects ; Infrared Rays ; Liposomes/chemistry ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Particle Size ; Photochemical Processes ; Quantum Dots/chemistry ; Sulfides/chemistry ; Surface Properties ; *Temperature ; Tungsten Compounds/chemistry ; Vancomycin/chemistry/*pharmacology ; Vancomycin-Resistant Staphylococcus aureus/*drug effects ; }, abstract = {Nanozymes that mimic peroxidase (POD) activity can convert H2O2 into bactericidal free radicals, which is referred to as chemodynamic therapy (CDT). High glutathione (GSH) levels in the infectious tissue severely limit the performance of CDT. Herein, we report a near-infrared-controlled antibacterial nanoplatform that is based on encapsulating tungsten sulfide quantum dots (WS2QDs) and the antibiotic vancomycin in a thermal-sensitive liposome. The system exploits the photothermal sensitivity of the WS2QDs to achieve selective liposome rupture for the targeted drug delivery. We determined that WS2QDs show a strong POD-like activity under physiological conditions and the oxidase-like activity, which can oxidate GSH to further improve the CDT efficacy. Moreover, we found that increased temperature promotes multiple enzyme-mimicking activities of WS2QDs. This platform exerts antibacterial effects against Gram-positive Mu50 (a vancomycin-intermediate Staphylococcus aureus reference strain) and Gram-negative Escherichia coli and disrupts biofilms for improved penetration of therapeutic agents inside biofilms. In vivo studies with mice bearing Mu50-caused skin abscess revealed that this platform confers potent antibacterial activity without obvious toxicity. Accordingly, our work illustrates that the photothermal and nanozyme properties of WS2QDs can be deployed alongside a conventional therapeutic to achieve synergistic chemodynamic/photothermal/pharmaco therapy for powerful antibacterial effects.}, } @article {pmid33107455, year = {2020}, author = {Kaur, G and Kumar Reddy, TV and Venkatesh, KV and Mahalakshmi, K}, title = {Effects of chitosan oligosaccharide and calcium hypochlorite on E. Faecali dentinal biofilm and smear layer removal - SEM analysis.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {31}, number = {4}, pages = {550-556}, doi = {10.4103/ijdr.IJDR_334_20}, pmid = {33107455}, issn = {1998-3603}, mesh = {Biofilms ; Calcium Compounds ; *Chitosan/pharmacology ; Edetic Acid ; Humans ; Microscopy, Electron, Scanning ; Oligosaccharides ; Root Canal Irrigants/pharmacology ; Root Canal Preparation ; *Smear Layer ; }, abstract = {BACKGROUND: The complex structure and irregularities of root canal walls are liable for infection by several bacterial species. Thus, the use of irrigants and auxiliary chemical solutions associated with instrumentation is necessary for effective eradication of the biofilm as well as complete removal of the smear layer.

AIM: To evaluate the effects of calcium hypochlorite and chitosan oligosaccharide (COS) in disinfecting Enterococcus faecalis root canal biofilm and smear layer removal with minimal erosion.

MATERIALS AND METHODS: A total of 70 mandibular premolars were decoronated at the cementoenamel junction. The samples were biomechanically prepared, sterilized in an autoclave, and incubated with E. faecalis (ATCC-29212) bacteria for 21 days. Cleaning and shaping were done till maximum apical file size of #45 K. Specimens were randomly divided into 4 groups: GROUP I: Control Group, GROUP II: 5% Sodium Hypochlorite (NaOCl) solution followed by 17% EDTA solution, GROUP III: 5% Calcium Hypochlorite [Ca(OCl)2] solution followed by 17% EDTA solution and GROUP IV: 5% Ca(OCl)2 solution followed by 1% COS. The samples were subjected to microbial count followed by smear layer removal under scanning electron microscope (SEM) at coronal, middle and apical third.

STATISTICAL ANALYSIS USED: Kruskal-Wallis Test and post-hoc Scheffe's test.

RESULTS: It was observed that Group IV showed the lowest amount of CFU count/mL and the highest amount of smear layer removal with a statistically significant difference (P < 0.05) when compared with the other three Groups.

CONCLUSION: 5% Ca(OCl)2 solution with 1% COS solution effectively removed the Enterococcus faecalis biofilm and smear layer from the root canals with minimal erosion.}, } @article {pmid33107284, year = {2020}, author = {Erdal, B and Yalınay, M and Elmas, Ç and Yazıcı, GN}, title = {[Investigation of Pseudomonas aeruginosa Biofilm Formation and Quorum Sensing Genes in Piperacillin/Tazobactam and Ciprofloxacin Sub-minimal Inhibitory Concentrations].}, journal = {Mikrobiyoloji bulteni}, volume = {54}, number = {4}, pages = {547-558}, doi = {10.5578/mb.70087}, pmid = {33107284}, issn = {0374-9096}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Ciprofloxacin/pharmacology ; Microbial Sensitivity Tests ; Piperacillin ; *Pseudomonas aeruginosa/genetics ; *Quorum Sensing/drug effects/genetics ; Tazobactam ; }, abstract = {Pseudomonas aeruginosa is a non-fermentative, oxidase-positive, motile gram-negative bacillus widespread in nature. The virulence factors of P.aeruginosa including the ability to grow under minimal growth conditions, the widespread presence in nature, and the ability to form biofilms make P.aeruginosa a highly important bacterium along with its resistance mechanisms against many antibiotics. The ability to form biofilms increases the symptom severity in diseases caused by P.aeruginosa and causes difficulties in the treatment. The aim of this study was to investigate the effects of sub-minimal inhibitory concentrations (sub-MIC) of piperacillin/tazobactam (TZP) and ciprofloxacin (CIP) which are used for the treatment of P.aeruginosa infections on biofilm formation and to investigate the relationship between the severity of biofilm formation and Quorum Sensing (QS) genes. The study included 24 P.aeruginosa isolates from the culture collection of Medical Microbiology Laboratory of Gazi University Faculty of Medicine. MIC values of TZP and CIP antibiotics were determined by the microdilution method. The biofilm layers in the antibiotic-free medium and in the sub-MIC (MIC/2, MIC/4 ve MIC/8) concentrations of antibiotics were visualized by using a scanning electron microscope (SEM). The QS genes (lasI, lasR, rhlI, and rhlR) of the 24 isolates with known biofilm characteristics were identified via the amplification of chromosomal DNA by using PCR method. In the study, it was foundthat both antibiotics reduced biofilm formation in a dose-dependent manner in sub-MIC concentrations compared to the antibiotic-free condition and that MIC/2 was the concentration, which reduced the biofilm formation most. These results were further confirmed by viewing the SEM images. The QS genes lasI, lasR, and rhlI were detected in a total of 19 isolates with moderately strong and strong biofilm formation, the rhlR gene was detected in six of the strong biofilm-forming isolates, in four of the moderately strong biofilm-forming isolates, and in three of the weak biofilm-forming isolates, respectively. The investigation of the effects of sub-MIC concentrations of antimicrobials, used for the treatment of P.aeruginosa infections, on the biofilm formation of P.aeruginosa and the investigation and better understanding of the QS systems associated with biofilm production will allow for finding out new treatment approaches and offer different options in combating infections with high morbidity and mortality.}, } @article {pmid33107032, year = {2021}, author = {Arias-Moliz, MT and Baca, P and Solana, C and Toledano, M and Medina-Castillo, AL and Toledano-Osorio, M and Osorio, R}, title = {Doxycycline-functionalized polymeric nanoparticles inhibit Enterococcus faecalis biofilm formation on dentine.}, journal = {International endodontic journal}, volume = {54}, number = {3}, pages = {413-426}, doi = {10.1111/iej.13436}, pmid = {33107032}, issn = {1365-2591}, support = {MAT2017-85999P MINECO/AEI/FEDER/UE//Spanish Ministry of Economy and Competitiveness and European Regional Development Fund/ ; #CTS-167//Regional Government of Andalusia Research Fund/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Dentin ; Doxycycline/pharmacology ; *Enterococcus faecalis ; Humans ; Microscopy, Confocal ; *Nanoparticles ; Root Canal Irrigants ; }, abstract = {AIM: To evaluate in a laboratory setting the antimicrobial properties and the potential to inhibit biofilm formation of novel remineralizing polymeric nanoparticles (NPs) when applied to dentine surfaces and to ascertain the effect of the functionalization of these NPs with zinc, calcium or doxycycline.

METHODOLOGY: The antimicrobial activity and inhibition of biofilm formation of polymeric NPs were analysed on human dentine blocks that were infected with Enterococcus faecalis before or after application of NPs. LIVE/DEAD ® testing under Confocal Laser Scanning Microscopy and bacterial culturing were employed to analyse biofilm biovolume and bacterial viability. Field Emission Scanning Electron Microscopy was also employed to assess biofilm morphology. One-way anova with Welch's correction and post hoc comparison by the Games-Howell test were performed for comparisons between groups.

RESULTS: The un-functionalized NPs displayed the greatest antimicrobial activity against E. faecalis biofilms as they provided the lowest biovolume (3865.7 ± 2926.97 µm[3] ; P < 0.001) and the highest dead/injured cells percentage (79.93 ± 18.40%; P < 0.001), followed by Dox-NPs (biovolume: 19,041.55 ± 17,638.23 µm[3] , dead/injured cells: 45.53 ± 26.50%; P < 0.001). Doxycycline-loaded NPs had the largest values of inhibition of biofilm formation with the lowest biofilm biovolume (8517.65 ± 7055.81 µm[3] ; P < 0.001) and a high dead/injured bacterial percentage (68.68 ± 12.50%; P < 0.001). Un-functionalized NPs did not reduce biomass growth (P > 0.05), but attained the largest percentage of compromised cells (93 ± 8.23%; P < 0.001), being able to disrupt biofilm formation. It also produced occlusion of dentinal tubules, potentially interfering with bacterial tubule penetration.

CONCLUSIONS: A new generation of bioactive nano-fillers (doxycycline-functionalized polymeric NPs) had antibacterial activity and occluded dentinal tubules. Incorporating these NPs into endodontic sealers may have the potential to enhance the outcome of root canal treatment.}, } @article {pmid33106345, year = {2020}, author = {Nairn, BL and Lee, GT and Chumber, AK and Steck, PR and Mire, MO and Lima, BP and Herzberg, MC}, title = {Uncovering Roles of Streptococcus gordonii SrtA-Processed Proteins in the Biofilm Lifestyle.}, journal = {Journal of bacteriology}, volume = {203}, number = {2}, pages = {}, pmid = {33106345}, issn = {1098-5530}, support = {K08 DE027705/DE/NIDCR NIH HHS/United States ; R01 DE025618/DE/NIDCR NIH HHS/United States ; }, mesh = {Aminoacyltransferases/chemistry/*metabolism ; Animals ; Bacterial Proteins/chemistry/genetics/metabolism/*physiology ; Biofilms/*growth & development ; Cysteine Endopeptidases/chemistry/*metabolism ; Dental Plaque/microbiology ; Gene Deletion ; Hemagglutination ; Humans ; Hydrophobic and Hydrophilic Interactions ; Mouth/microbiology ; Saliva/microbiology ; Sheep/blood ; Streptococcus gordonii/genetics/growth & development/*physiology ; }, abstract = {Streptococcus gordonii is a commensal oral organism. Harmless in the oral cavity, S. gordonii is an opportunistic pathogen. S. gordonii adheres to body surfaces using surface adhesive proteins (adhesins), which are critical to subsequent formation of biofilm communities. As in most Gram-positive bacteria, S. gordonii surface proteins containing the C-terminal LPXTG motif cleavage sequence are processed by sortase A (SrtA) to become covalently attached to the cell wall. To characterize the functional diversity and redundancy in the family of SrtA-processed proteins, an S. gordonii DL1 markerless deletion mutant library was constructed of each of the 26 putative SrtA-processed proteins. Each library member was evaluated for growth in rich medium, biofilm formation on plastic, saliva and salivary fractions, cell surface hydrophobicity (CSH), hemagglutination, and integration into an ex vivo plaque biofilm community. Library members were compared to the non-SrtA-processed adhesins AbpA and AbpB. While no major growth differences in rich medium were observed, many S. gordonii LPXTG/A proteins impacted biofilm formation on one or more of the substrates. Several mutants showed significant differences in hemagglutination, hydrophobicity, or fitness in the ex vivo plaque model. From the identification of redundant and unique functions in these in vitro and ex vivo systems, functional stratification among the LPXTG/A proteins is apparent.IMPORTANCES. gordonii interactions with its environment depend on the complement of cell wall proteins. A subset of these cell wall proteins requires processing by the enzyme sortase A (SrtA). The identification of SrtA-processed proteins and their functional characterization will help the community to better understand how S. gordonii engages with its surroundings, including other microbes, integrates into the plaque community, adheres to the tooth surface, and hematogenously disseminates to cause blood-borne infections. This study identified 26 putative SrtA-processed proteins through creation of a markerless deletion mutant library. The library was subject to functional screens that were chosen to better understand key aspects of S. gordonii physiology and pathogenesis.}, } @article {pmid33105653, year = {2020}, author = {Ban, GH and Li, Y and Wall, MM and Jun, S}, title = {A Nanoengineered Stainless Steel Surface to Combat Bacterial Attachment and Biofilm Formation.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33105653}, issn = {2304-8158}, support = {2015-67017-23083//U.S. Department of Agriculture/ ; 58-2040-8-010//Agricultural Research Service/ ; }, abstract = {Nanopatterning and anti-biofilm characterization of self-cleanable surfaces on stainless steel substrates were demonstrated in the current study. Electrochemical etching in diluted aqua regia solution consisting of 3.6% hydrogen chloride and 1.2% nitric acid was conducted at 10 V for 5, 10, and 15 min to fabricate nanoporous structures on the stainless steel. Variations in the etching rates and surface morphologic characteristics were caused by differences in treatment durations; the specimens treated at 10 V for 10 min showed that the nanoscale pores are needed to enhance the self-cleanability. Under static and realistic flow environments, the populations of Escherichia coli O157:H7 and Salmonella Typhimurium on the developed features were significantly reduced by 2.1-3.0 log colony-forming unit (CFU)/cm[2] as compared to bare stainless steel (p < 0.05). The successful fabrication of electrochemically etched stainless steel surfaces with Teflon coating could be useful in the food industry and biomedical fields to hinder biofilm formation in order to improve food safety.}, } @article {pmid33105606, year = {2020}, author = {Zayed, AR and Pecellin, M and Salah, A and Alalam, H and Butmeh, S and Steinert, M and Lesnik, R and Brettar, I and Höfle, MG and Bitar, DM}, title = {Characterization of Legionella pneumophila Populations by Multilocus Variable Number of Tandem Repeats (MLVA) Genotyping from Drinking Water and Biofilm in Hospitals from Different Regions of the West Bank.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {33105606}, issn = {2076-0817}, support = {DFG grant (HO 930/5-1&2)//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The West Bank can be considered a high-risk area for Legionnaires' disease (LD) due to its hot climate, intermittent water supply and roof storage of drinking water. Legionella, mostly L. pneumophila, are responsible for LD, a severe, community-acquired and nosocomial pneumonia. To date, no extensive assessment of Legionella spp and L. pneumophila using cultivation in combination with molecular approaches in the West Bank has been published. Two years of environmental surveillance of Legionella in water and biofilms in the drinking water distribution systems (DWDS) of eight hospitals was carried out; 180 L. pneumophila strains were isolated, mostly from biofilms in DWDS. Most of the isolates were identified as serogroup (Sg) 1 (60%) and 6 (30%), while a minor fraction comprised Sg 8 and 10. Multilocus Variable number of tandem repeats Analysis using 13 loci (MLVA-8(12)) was applied as a high-resolution genotyping method and compared to the standard Sequence Based Typing (SBT). The isolates were genotyped in 27 MLVA-8(12) genotypes (Gt), comprising four MLVA clonal complexes (VACC 1; 2; 5; 11). The major fraction of isolates constituted Sequence Type (ST)1 and ST461. Most of the MLVA-genotypes were highly diverse and often unique. The MLVA-genotype composition showed substantial regional variability. In general, the applied MLVA-method made it possible to reproducibly genotype the isolates, and was consistent with SBT but showed a higher resolution. The advantage of the higher resolution was most evident for the subdivision of the large strain sets of ST1 and ST461; these STs were shown to be highly pneumonia-relevant in a former study. This shows that the resolution by MLVA is advantageous for back-tracking risk sites and for the avoidance of outbreaks of L. pneumophila. Overall, our results provide important insights into the detailed population structure of L. pneumophila, allowing for better risk assessment for DWDS.}, } @article {pmid33104976, year = {2021}, author = {Bystrianský, L and Hujslová, M and Gryndler, M}, title = {Study of the effects of mineral salts on the biofilm formation on polypropylene fibers using three quantification methods.}, journal = {Folia microbiologica}, volume = {66}, number = {1}, pages = {133-143}, pmid = {33104976}, issn = {1874-9356}, support = {17-09946S//Grantová Agentura České Republiky/ ; CZ.02.1.01/0.0/0.0/16_013/0001821//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; }, mesh = {Bacteria/classification/drug effects/genetics/isolation & purification ; Bacteriological Techniques ; Biofilms/*drug effects/growth & development ; Biomass ; Culture Media/chemistry ; Microbiota/drug effects ; Minerals/analysis/*pharmacology ; Polypropylenes ; Salts/analysis/*pharmacology ; Soil Microbiology ; }, abstract = {The microbial biofilms are ubiquitous in nature and represent important biological entities that affect various aspects of human life. As such, they attracted considerable attention during last decades, with the factors affecting the biofilm development being among the frequently studied topics. In our work, the biofilm was cultivated on the surface of polypropylene fibers in a nutrient medium inoculated by the suspension of two unsterile soils. The effects of ionic strength and valence of salt on the amount of the produced biofilm and on composition of biofilm microbial communities were investigated. The effect of valence was significant in some OTUs: Arthrobacter/Pseudarthrobacter/Paenarthrobacter and Bacillus with positive response to monovalent salt (KCl) and Streptomyces, Lysinibacillus, Pseudomonas, and Ensifer with positive response to divalent salt (MgSO4). The significant preference for a certain concentration of salts was observed in the case of OTUs Agrobacterium, Bacillus (both 100 mM), and Brevundimonas (30 mM). A new quantification method based on measuring of oxidizable organic carbon in biofilm biomass, based on dichromate oxidation, was used. We compared the results obtained using this method with results of crystal violet destaining and measuring of extracted DNA concentration as proxies of the biofilm biomass. The dichromate oxidation is simple, inexpensive, and fast, and our results show that it may be more sensitive than crystal violet destaining. The highest biomass values tended to associate with high concentrations of the divalent salt. This trend was not observed in treatments where the monovalent salt was added. Our data confirm the importance of inorganic ions for biofilm composition and biomass accumulation.}, } @article {pmid33104852, year = {2021}, author = {Zhang, C and Wang, C and Xiu, Z}, title = {Regulation of c-di-GMP in Biofilm Formation of Klebsiella pneumoniae in Response to Antibiotics and Probiotic Supernatant in a Chemostat System.}, journal = {Current microbiology}, volume = {78}, number = {1}, pages = {133-143}, pmid = {33104852}, issn = {1432-0991}, support = {No. 21476042//National Natural Science Foundation of China (CN)/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Cyclic GMP/analogs & derivatives ; Gene Expression Regulation, Bacterial ; *Klebsiella pneumoniae/genetics/metabolism ; *Probiotics ; }, abstract = {The resistance of bacteria to antibiotics is a major public health issue. Klebsiella pneumoniae is a type exemplification of multi-resistant enterobacteria. Its high biofilm forming capacity is a major factor in the recurrent infection of the intestinal tract. In this study, the intrinsic mechanism of secondary growth of K. pneumoniae in response to antibiotics and the inhibition effect of probiotic supernatant on biofilm formation after antibiotic treatment were investigated in a polyester nonwoven chemostat bioreactor. The experimental results showed that the c-di-GMP content in the cells increased after treatment with levofloxacin, leading to the formation of a thick biofilm due to an increase in the production of extracellular polymer substance (EPS) and type 3 fimbriae. Biofilm prevents the mass transfer of levofloxacin and protects K. pneumoniae cells from being killed by levofloxacin. Under suitable conditions, K. pneumoniae cells on the biofilm enter into the suspension for secondary growth. Moreover, the inhibition of probiotic supernatant on the biofilm formation was mainly due to the reduced expression of yfiN and mrkJ genes, and the decreased concentration of c-di-GMP in cells, as well as the less secretion of EPS. At the same time, the decrease in the concentration of c-di-GMP also reduced the expression of the mrkABCDF gene and prevented the synthesis of the type 3 fimbriae. The results would help to understand the mechanism of antibiotic resistance of pathogenic bacteria and to provide evidence to address this problem through the use of probiotics.}, } @article {pmid33103954, year = {2020}, author = {Zhang, L and Li, Y and Zhang, Q and Du, N and Li, X and Zhang, Q and Yuan, L and Dong, F and Jiang, Y and Tang, J and Wang, Y}, title = {Antimicrobial Activity of an Implantable Wireless Blue Light-Emitting Diode Against Root Canal Biofilm In Vitro.}, journal = {Photobiomodulation, photomedicine, and laser surgery}, volume = {38}, number = {11}, pages = {694-702}, doi = {10.1089/photob.2020.4821}, pmid = {33103954}, issn = {2578-5478}, mesh = {*Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; *Photochemotherapy ; }, abstract = {Objective: We developed an implantable wireless blue micro light-emitting diode (micro-LED) device and evaluated the utility of continuous antimicrobial blue light (aBL) irradiation emitted from this micro-LED for root canal disinfection. Methods: An implantable wireless blue micro-LED device (peak wavelength: 410 nm, maximum power: 15 mW) was developed to be placed in the root canal. Optical transmission of the device in human dentin tissue was simulated using Monte Carlo ray-tracing method. The bactericidal effect of low-level aBL on planktonic root canal infection-related bacteria [Enterococcus faecalis, methicillin-resistant Streptococcus aureus (MRSA), and Prevotella intermedia] was evaluated by colony counting. The biocompatibility of continuous low-level aBL exposure was evaluated by infrared thermal imaging and cell viability tests. Thirty extracted intact human single-rooted teeth were prepared and the root canals were infected with E. faecalis for 14 days to form biofilm. The infected root canals were randomly divided into three groups (n = 10), and treated with normal saline (group NS), calcium hydroxide (group CH), and micro-LED device (group aBL) for 3 and 7 days. The bactericidal effect of each group was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results: Monte Carlo simulation showed that blue light irradiation of the micro-LED device decreased exponentially with the light transmission distance through human dentin tissue. Planktonic E. faecalis, MRSA, and P. intermedia were significantly eliminated after irradiation with 432, 36, and 1.35 J/cm[2] aBL, respectively (p < 0.05). Infrared thermal imaging and cell viability tests showed that continuous aBL exposure is biocompatible in vitro. CLSM and SEM analyses revealed that the micro-LED device had a greater antimicrobial effect than CH on E. faecalis biofilm in the root canal. Conclusions: The wireless blue micro-LED device is a promising and user-friendly approach for root canal disinfection that will facilitate infection control in the root canal using aBL.}, } @article {pmid33103466, year = {2020}, author = {Paul Bhattacharya, S and Mitra, A and Bhattacharya, A and Sen, A}, title = {Quorum quenching activity of pentacyclic triterpenoids leads to inhibition of biofilm formation by Acinetobacter baumannii.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {922-937}, doi = {10.1080/08927014.2020.1831480}, pmid = {33103466}, issn = {1029-2454}, mesh = {*Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Chromobacterium ; Molecular Docking Simulation ; Pseudomonas aeruginosa ; Quorum Sensing/drug effects ; Triterpenes/pharmacology ; }, abstract = {The quorum quenching (QQ) potential of three pentacyclic triterpenoids, glycyrrhetinic acid (GRA), ursolic acid (UA) and betulinic acid (BA), representing distinct groups of compounds, was evaluated. Violacein production by Chromobacterium violaceum and pyocyanin production by Pseudomonas aeruginosa were severely affected by GRA, UA and BA, suggesting a perturbation of N-acyl homoserine lactone (ASL) based signaling. Molecular docking analysis revealed a possible interaction between ASL-synthase and ASL-dependent transcriptional activator homologs from P. aeruginosa and Acinetobacter baumannii with common binding pockets for GRA, UA and BA. The triterpenoids inhibited biofilm formation by A. baumannii and affected the overall structure of biofilms. When administered in combination, two of the three molecules fostered antibiotic action against A. baumannii biofilms, widening the scope for developing novel combinations against the pathogen.}, } @article {pmid33102540, year = {2020}, author = {Torres, G and Vargas, K and Cuesta-Astroz, Y and Reyes-Vélez, J and Olivera-Angel, M}, title = {Phenotypic Characterization and Whole Genome Analysis of a Strong Biofilm-Forming Staphylococcus aureus Strain Associated With Subclinical Bovine Mastitis in Colombia.}, journal = {Frontiers in veterinary science}, volume = {7}, number = {}, pages = {530}, pmid = {33102540}, issn = {2297-1769}, abstract = {Staphylococcus aureus represent a serious threat to public health due to food safety, antibiotic resistance, and the potential zoonotic transmission of strains between dairy cattle and humans. Biofilm formation by S. aureus results in chronicity of the infections which confers protection against the immune response and antibiotics. Likewise, biofilm allows the exchange of mobile genetic material among different strains through microbial interactions inside the matrix. In Colombia, where S. aureus continues to be one of the main pathogens isolated from bovine intramammary infections and where milking by hand is highly frequent, there are knowledge gaps on the zoonotic potential of the strains. Therefore, the aim of this work was to characterize genotypically and phenotypically the S. aureus Sa1FB strain with strong biofilm production and to perform genomic and phenotypic comparisons with other relevant S. aureus strains (native and references strains). These results show a highly productive strain of biofilm and a low ability of cell invasion compared to the other two native strains. In addition, high genomic similarity between S. aureus Sa1FB and the reference strains was observed, despite of the differences reported at the clinical level. However, Sa1FB exhibited special features in terms of mobile genetic elements, highlighting its ability to accept foreign genetic material. Indeed, this could increase mutation, pathogenesis, and adaptability to new hosts, representing a risk for people in contact with the milk obtained from animals infected with these strains. These results present the relevance of surveillance for early detection of emergent clones with zoonotic potential, which reduces the risk of occupational exposure and their spread in the community.}, } @article {pmid33102249, year = {2020}, author = {Deng, Z and Luo, XM and Liu, J and Wang, H}, title = {Quorum Sensing, Biofilm, and Intestinal Mucosal Barrier: Involvement the Role of Probiotic.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {538077}, pmid = {33102249}, issn = {2235-2988}, mesh = {Bacteria ; Biofilms ; Intestinal Mucosa ; *Probiotics ; *Quorum Sensing ; }, abstract = {The intestine is a particularly dynamic environment in which the host constantly interacts with trillions of symbiotic bacteria called the microbiota. Using quorum sensing (QS) communication, bacteria can coordinate their social behavior and influence host cell activities in a non-invasive manner. Nowadays, a large amount of research has greatly spurred the understanding of how bacterial QS communication regulates bacterial cooperative behaviors due to coexistence and host-microbe interactions. In this review, we discuss bacterial QS in the gut and its role in biofilm formation. As a biological barrier, the mucosal immune system can effectively prevent pathogenic microorganisms and other immunogenic components from entering the internal environment of the host. We focus on the relationship between biofilm and intestinal mucosal immunity, and how probiotic bacteria may regulate them. This review is to provide a theoretical basis for the development of new techniques including probiotics targeting the intestinal barrier function, thereby improving gut health.}, } @article {pmid33102194, year = {2020}, author = {Thinina, AC and Karim, H and Alia, MM and Karim, A}, title = {Evaluation and quantification of the inhibition of biofilm and planktonic forms of Klebsiella pneumoniae by the polyphenolic extract of Pulicaria crispa.}, journal = {Journal of advanced pharmaceutical technology & research}, volume = {11}, number = {3}, pages = {117-122}, pmid = {33102194}, issn = {2231-4040}, abstract = {Analyses of polyphenolic plant extracts have shown significant results when used to control different pathogens. Many of these pathogens are responsible for different infections causing significant public health problems. This work aims basically to determine the efficiency of polyphenolic extract of Pulicaria crispa to prevent biofilm formation by Klebsiella pneumoniae. Strains were identified by their biochemical characters and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. P. crispa is a Saharan plant used to extract polyphenols to assess their inhibitory action against K. pneumoniae development and biofilm forming. High-performance liquid chromatography revealed quercetin as the most important component of the polyphenolic extract. All strains are biofilm forming and are resistant to many antibiotics. The Minimal inhibitory concentrations of biofilm (MICBs) of the extract range from 0.21 mg gallic acid equivalent (GAE) to 3.40 mg GAE. The minimal inhibitory concentrations vary from 0.1 mg GAE to 0.425 mg GAE. Although many plant extracts have already shown their antimicrobial and antibiofilm activities, their application in clinical cases requires a long-term endeavor.}, } @article {pmid33101239, year = {2020}, author = {Mayer, C and Muras, A and Parga, A and Romero, M and Rumbo-Feal, S and Poza, M and Ramos-Vivas, J and Otero, A}, title = {Quorum Sensing as a Target for Controlling Surface Associated Motility and Biofilm Formation in Acinetobacter baumannii ATCC[®] 17978[TM].}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {565548}, pmid = {33101239}, issn = {1664-302X}, abstract = {The important nosocomial pathogen Acinetobacter baumannii presents a quorum sensing (QS) system (abaI/abaR) mediated by acyl-homoserine-lactones (AHLs) and several quorum quenching (QQ) enzymes. However, the roles of this complex network in the control of the expression of important virulence-related phenotypes such as surface-associated motility and biofilm formation is not clear. Therefore, the effect of the mutation of the AHL synthase AbaI, and the exogenous addition of the QQ enzyme Aii20J on surface-associated motility and biofilm formation by A. baumannii ATCC[®] 17978[TM] was studied in detail. The effect of the enzyme on biofilm formation by several multidrug-resistant A. baumannii clinical isolates differing in their motility pattern was also tested. We provide evidence that a functional QS system is required for surface-associated motility and robust biofilm formation in A. baumannii ATCC[®] 17978[TM]. Important differences were found with the well-studied strain A. nosocomialis M2 regarding the relevance of the QS system depending on environmental conditions The in vitro biofilm-formation capacity of A. baumannii clinical strains was highly variable and was not related to the antibiotic resistance or surface-associated motility profiles. A high variability was also found in the sensitivity of the clinical strains to the action of the QQ enzyme, revealing important differences in virulence regulation between A. baumannii isolates and confirming that studies restricted to a single strain are not representative for the development of novel antimicrobial strategies. Extracellular DNA emerges as a key component of the extracellular matrix in A. baumannii biofilms since the combined action of the QQ enzyme Aii20J and DNase reduced biofilm formation in all tested strains. Results demonstrate that QQ strategies in combination with other enzymatic treatments such as DNase could represent an alternative approach for the prevention of A. baumannii colonization and survival on surfaces and the prevention and treatment of infections caused by this pathogen.}, } @article {pmid33100852, year = {2020}, author = {Wu, X and Al Farraj, DA and Rajaselvam, J and Alkufeidy, RM and Vijayaraghavan, P and Alkubaisi, NA and Agastian, P and Alshammari, MK}, title = {Characterization of biofilm formed by multidrug resistant Pseudomonas aeruginosa DC-17 isolated from dental caries.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {11}, pages = {2955-2960}, pmid = {33100852}, issn = {1319-562X}, abstract = {The present work reports with the screening of biofilm-producing bacteria from the dental caries. The dental pathogens showed resistance against various antibiotics and biofilm forming ability at various levels. Among the bacterial strain, Pseudomonas aeruginosa DC-17 showed enhanced biofilm production. Extracellular polymeric substance (EPS) was synthesized by the selected bacterial isolate considerably and contributed as the major component of biofilm. EPS composed of eDNA, proteins and lipids. The total protein content of the EPS was found to be 1.928 mg/mL and was the major component than carbohydrate and DNA. Carbohydrate content was 162.3 mg/L and DNA content of EPS was 4.95 μg/mL. These macromolecules interacted in the matrix to develop dynamic and specific interactions to signalling biofilm to differentiating various environments. Also, the isolated bacteria showed resistant against various commercially available antibiotics. The isolates showed more resistance against penicillin (98%) and were sensitive against amoxicillin. Among the factors, temperature, pH and sugar concentration influenced biofilm formation. Biofilm forming ability of the selected bacterial stain was tested at various pH values and alkaline pH was favoured for biofilm production. Biofilm production was found to be maximum at 40 °C and 8% sucrose enhanced biofilm formation. Biofilm formed by P. aeruginosa DC-17 was resistant against various tested antimicrobials and chemicals.}, } @article {pmid33100201, year = {2021}, author = {Bamunuarachchi, NI and Khan, F and Kim, YM}, title = {Inhibition of Virulence Factors and Biofilm Formation of Acinetobacter Baumannii by Naturally-derived and Synthetic Drugs.}, journal = {Current drug targets}, volume = {22}, number = {7}, pages = {734-759}, pmid = {33100201}, issn = {1873-5592}, mesh = {Acinetobacter Infections/drug therapy ; *Acinetobacter baumannii/drug effects ; *Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; *Biological Products/pharmacology ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; *Synthetic Drugs/pharmacology ; Virulence Factors/*antagonists & inhibitors ; }, abstract = {Acinetobacter baumannii is a gram-negative, aerobic, non-motile, and pleomorphic bacillus. A. baumannii is also a highly-infectious pathogen causing high mortality and morbidity rates in intensive care units. The discovery of novel agents against A. baumannii infections is urgently needed due to the emergence of drug-resistant A. baumannii strains and the limited number of efficacious antibiotics available for treatment. In addition to the production of several virulence factors, A. baumannii forms biofilms on the host cell surface as well. Formation of biofilms occurs through initial surface attachment, microcolony formation, biofilm maturation, and detachment stages, and is one of the major drug resistance mechanisms employed by A. baumannii. Several studies have previously reported the efficacy of naturally-derived and synthetic compounds as anti- biofilm and anti-virulence agents against A. baumannii. Here, inhibition of biofilm formation and virulence factors of A. baumannii using naturally-derived and synthetic compounds are reviewed.}, } @article {pmid33099201, year = {2021}, author = {Catao, ECP and Gallois, N and Fay, F and Misson, B and Briand, JF}, title = {Metal resistance genes enrichment in marine biofilm communities selected by biocide-containing surfaces in temperate and tropical coastal environments.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {268}, number = {Pt A}, pages = {115835}, doi = {10.1016/j.envpol.2020.115835}, pmid = {33099201}, issn = {1873-6424}, mesh = {Biofilms ; *Disinfectants ; Mediterranean Sea ; Metals ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Microorganisms able to form biofilms in marine ecosystems are selected depending on immersed surfaces and environmental conditions. Cell attachment directly on toxic surfaces like antifouling coatings suggests a selection of tolerant (or resistant) organisms with characteristics conferring adaptive advantages. We investigated if environment would drive metal resistance gene abundance in biofilms on artificial surfaces. Biofilms were sampled from three surfaces (a PVC reference and two antifouling coatings) deployed in three coastal waters with dissimilar characteristics: The Mediterranean Sea (Toulon) and Atlantic (Lorient) and Indian (Reunion) Oceans. The two coatings differed in metals composition, either Cu thiocyanate and Zn pyrithione (A3) or Cu2O (Hy). Metal resistance genes (MRG) specific to copper (cusA, copA, cueO) or other metals (czcA and pbrT) were monitored with qPCR in parallel to the microbial community using 16S rRNA gene metabarcoding. A lower α-diversity on A3 or Hy than on PVC was observed independent on the site. Weighted Unifrac suggested segregation of communities primarily by surface, with lower site effect. Metacoder log2 fold change ratio and LeFSe discrimination suggested Marinobacter to be specific of Hy and Altererythrobacter, Erythrobacter and Sphingorhabdus of A3. Likewise, the relative abundance of MRG (MRG/bacterial 16S rRNA) varied between surfaces and sites. A3 presented the greatest relative abundances for cusA, cueO and czcA. The latter could only be amplified from A3 communities, except at Toulon. Hy surface presented the highest relative abundance for copA, specifically at Lorient. These relative abundances were correlated with LeFSe discriminant taxa. Dasania correlated positively with all MRG except cueO. Marinobacter found in greater abundance in Hy biofilm communities correlated with the highest abundances of copA and Roseovarius with czcA. These results prove the selection of specific communities with abilities to tolerate metallic biocides forming biofilms over antifouling surfaces, and the secondary but significant influence of local environmental factors.}, } @article {pmid33098913, year = {2021}, author = {Liu, Y and Li, Y and Shi, L}, title = {Controlled drug delivery systems in eradicating bacterial biofilm-associated infections.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {329}, number = {}, pages = {1102-1116}, doi = {10.1016/j.jconrel.2020.10.038}, pmid = {33098913}, issn = {1873-4995}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Anti-Infective Agents/therapeutic use ; *Bacterial Infections/drug therapy ; Biofilms ; Drug Delivery Systems ; Humans ; }, abstract = {Drug delivery systems (DDS) have extensively progressed over the past decades for eradicating the bacteria embedded in biofilms while minimizing the side effects of antimicrobials on the normal tissues. They possess potential in solving the challenges of intrinsic antimicrobial-resistance and poor penetration of antimicrobials into biofilms. However, the guidelines for developing a controlled DDS for combating bacterial biofilms are limited. In this review, classical mechanisms and mathematical models of DDS were summarized in order to lay the foundation of controlled DDS development. Strategies for building controlled DDS were proposed based on the process of biofilm formation, including surface coatings, fibers, nanoparticles as DDS to prevent biofilm formation and eradicate bacterial biofilm-associated infections. The challenges that still remain in DDS design were discussed and future directions were suggested. We hope this review could give a "road map" to inspire readers and boost the development of the new generation of controlled drug release system for antimicrobial applications.}, } @article {pmid33097679, year = {2020}, author = {Chirathanamettu, TR and Pawar, PD}, title = {Quorum sensing-induced phenotypic switching as a regulatory nutritional stress response in a competitive two-species biofilm: An individual-based cellular automata model.}, journal = {Journal of biosciences}, volume = {45}, number = {}, pages = {}, pmid = {33097679}, issn = {0973-7138}, mesh = {Bacterial Infections/genetics/microbiology ; Biofilms/*growth & development ; Humans ; Hydroxyquinolines/metabolism ; Models, Biological ; Phenotype ; Pseudomonas aeruginosa/genetics/*growth & development/pathogenicity ; Quorum Sensing/genetics ; Staphylococcus aureus/genetics/*growth & development/pathogenicity ; Stress, Physiological/*genetics ; }, abstract = {Competition for nutrients in a polymicrobial biofilm may lead to susceptible species being subjected to nutritional stress. The influence of bacterial growth rates and interspecies interactions on their susceptibility and response to nutritional stress is not well understood. Pseudomonas aeruginosa and Staphylococcus aureus are two prevalent causative pathogens that coexist in biofilm-associated infections. Despite being the slower-growing species, P. aeruginosa dominates in a two-species biofilm by inducing phenotypic switching of S. aureus to a metabolicallychallenged small colony variant (SCV) via the release of 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). We hypothesize that P. aeruginosa experiences nutritional stress in competition with S. aureus, and that the release of HQNO is an adaptive response to nutritional stress.We present an individual-based two-species biofilm model in which interactions between entities induce emergent properties. As the biofilm matured, the difference in growth rates of the two species caused a non-uniform distribution of nutrients leading to nutritional stress for P. aeruginosa and a concurrent increase in the proportion of S. aureus subpopulation. The latter resulted in increased release of autoinducer, and subsequently the upregulation of P. aeruginosa cells via quorum sensing. Upregulated P. aeruginosa cells released HQNO at enhanced rates, thereby inducing phenotypic switching of S. aureus to SCVs which consume nutrient at a reduced rate. This shifted the nutrient distribution back in favor of P. aeruginosa, thereby relieving nutritional stress. Increase in nutritional stress potentiated the transformation of S. aureus into SCVs. HQNO production decreased once nutritional stress was relieved, indicating that phenotypic switching acts as a regulatory stress-adaptive response.}, } @article {pmid33097507, year = {2020}, author = {Alio, I and Gudzuhn, M and Pérez García, P and Danso, D and Schoelmerich, MC and Mamat, U and Schaible, UE and Steinmann, J and Yero, D and Gibert, I and Kohl, TA and Niemann, S and Gröschel, MI and Haerdter, J and Hackl, T and Vollstedt, C and Bömeke, M and Egelkamp, R and Daniel, R and Poehlein, A and Streit, WR}, title = {Phenotypic and Transcriptomic Analyses of Seven Clinical Stenotrophomonas maltophilia Isolates Identify a Small Set of Shared and Commonly Regulated Genes Involved in the Biofilm Lifestyle.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {24}, pages = {}, pmid = {33097507}, issn = {1098-5336}, mesh = {*Biofilms ; Europe ; Gene Expression Profiling ; *Genes, Bacterial ; *Genetic Variation ; Phenotype ; Proteolysis ; Stenotrophomonas maltophilia/genetics/*pathogenicity/*physiology ; Virulence ; }, abstract = {Stenotrophomonas maltophilia is one of the most frequently isolated multidrug-resistant nosocomial opportunistic pathogens. It contributes to disease progression in cystic fibrosis (CF) patients and is frequently isolated from wounds, infected tissues, and catheter surfaces. On these diverse surfaces S. maltophilia lives in single-species or multispecies biofilms. Since very little is known about common processes in biofilms of different S. maltophilia isolates, we analyzed the biofilm profiles of 300 clinical and environmental isolates from Europe of the recently identified main lineages Sgn3, Sgn4, and Sm2 to Sm18. The analysis of the biofilm architecture of 40 clinical isolates revealed the presence of multicellular structures and high phenotypic variability at a strain-specific level. Further, transcriptome analyses of biofilm cells of seven clinical isolates identified a set of 106 shared strongly expressed genes and 33 strain-specifically expressed genes. Surprisingly, the transcriptome profiles of biofilm versus planktonic cells revealed that just 9.43% ± 1.36% of all genes were differentially regulated. This implies that just a small set of shared and commonly regulated genes is involved in the biofilm lifestyle. Strikingly, iron uptake appears to be a key factor involved in this metabolic shift. Further, metabolic analyses implied that S. maltophilia employs a mostly fermentative growth mode under biofilm conditions. The transcriptome data of this study together with the phenotypic and metabolic analyses represent so far the largest data set on S. maltophilia biofilm versus planktonic cells. This study will lay the foundation for the identification of strategies for fighting S. maltophilia biofilms in clinical and industrial settings.IMPORTANCE Microorganisms living in a biofilm are much more tolerant to antibiotics and antimicrobial substances than planktonic cells are. Thus, the treatment of infections caused by microorganisms living in biofilms is extremely difficult. Nosocomial infections (among others) caused by S. maltophilia, particularly lung infection among CF patients, have increased in prevalence in recent years. The intrinsic multidrug resistance of S. maltophilia and the increased tolerance to antimicrobial agents of its biofilm cells make the treatment of S. maltophilia infection difficult. The significance of our research is based on understanding the common mechanisms involved in biofilm formation of different S. maltophilia isolates, understanding the diversity of biofilm architectures among strains of this species, and identifying the differently regulated processes in biofilm versus planktonic cells. These results will lay the foundation for the treatment of S. maltophilia biofilms.}, } @article {pmid33097267, year = {2021}, author = {Fu, Y and Peng, H and Liu, J and Nguyen, TH and Hashmi, MZ and Shen, C}, title = {Occurrence and quantification of culturable and viable but non-culturable (VBNC) pathogens in biofilm on different pipes from a metropolitan drinking water distribution system.}, journal = {The Science of the total environment}, volume = {764}, number = {}, pages = {142851}, doi = {10.1016/j.scitotenv.2020.142851}, pmid = {33097267}, issn = {1879-1026}, mesh = {Biofilms ; China ; *Drinking Water ; RNA, Ribosomal, 16S ; Water Microbiology ; Water Supply ; }, abstract = {Waterborne pathogens have been found in biofilms grown in drinking water distribution system (DWDS). However, there is a lack of quantitative study on the culturability of pathogens in biofilms from metropolitan DWDS. In this study, we quantified culturable and viable but non-culturable (VBNC) Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Vibrio cholerae in biofilms collected from five kinds of pipes (galvanized steel pipe, steel pipe, stainless steel clad pipe, ductile cast iron pipe and polyethylene pipe) and associated drinking water at an actual chlorinated DWDS in use from China. The results of these comprehensive analyses revealed that pipe material is a significant factor influencing the culturability of pathogen and microbial communities. Network analysis of the culturable pathogens and 16S rRNA gene inferred potential interactions between microbiome and culturability of pathogens. Although the water quality met the Chinese national standard of drinking water, however, VBNC pathogens were detected in both biofilms and water from the DWDS. This investigation suggests that stainless steel clad pipe (SSCP) was a better choice for pathogen control compared with other metal pipes. To our knowledge, this is the first study on culturable and VBNC pathogens in biofilms of different pipe materials in metropolitan DWDS.}, } @article {pmid33093606, year = {2020}, author = {Peng, Q and Lin, F and Ling, B}, title = {In vitro activity of biofilm inhibitors in combination with antibacterial drugs against extensively drug-resistant Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {18097}, pmid = {33093606}, issn = {2045-2322}, mesh = {Acinetobacter Infections/*drug therapy/microbiology ; Acinetobacter baumannii/*drug effects/isolation & purification ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/drug effects/*growth & development ; Drug Resistance, Multiple, Bacterial/*drug effects ; *Drug Synergism ; Drug Therapy, Combination ; Humans ; In Vitro Techniques ; }, abstract = {Acinetobacter baumannii is a common pathogen of nosocomial infection, and its ability to form biofilms further contributes to its virulence and multidrug resistance, posing a great threat to global public health. In this study, we investigated the inhibitory effects of five biofilm inhibitors (BFIs) (zinc lactate, stannous fluoride, furanone, azithromycin, and rifampicin) on biofilm formation of nine extensively drug-resistant A. baumannii (XDRAB), and assessed the synergistic antibacterial effects of these BFIs when combined with one of four conventional anti-A. baumannii antibiotics (imipenem, meropenem, tigecycline, and polymyxin B). Each of the five BFIs tested was found to be able to significantly inhibit biofilm formation of all the clinical isolates tested under sub-minimal inhibitory concentrations. Then, we observed synergistic effects (in 22%, 56% and 11% of the isolates) and additive effects (56%, 44% and 44%) when zinc lactate, stannous fluoride and furanone were combined with tigecycline, respectively. When zinc lactate and stannous fluoride were each used with a carbapenem (imipenem or meropenem), in 33% and 56-67% of the isolates, they showed synergistic and additive effects, respectively. Additivity in > 50% of the isolates was detected when rifampicin was combined with imipenem, meropenem, tigecycline, or polymyxin B; and a 100% additivity was noted with azithromycin-polymyxin B combination. However, antagonism and indifference were noted for polymyxin B in its combination with zinc lactate and stannous fluoride, respectively. In conclusion, five BFIs in combination with four antibacterial drugs showed different degrees of in vitro synergistic and additive antibacterial effects against XDRAB.}, } @article {pmid33092628, year = {2020}, author = {Wang, T and Ma, W and Jiang, Z and Bi, L}, title = {The penetration effect of HMME-mediated low-frequency and low-intensity ultrasound against the Staphylococcus aureus bacterial biofilm.}, journal = {European journal of medical research}, volume = {25}, number = {1}, pages = {51}, pmid = {33092628}, issn = {2047-783X}, support = {2016RQQXJ216//the Technology Research and Development Project of Harbin/ ; QC2016119//the Natural Science Foundation of Heilongjiang Province/ ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Hematoporphyrins/chemistry/*pharmacology ; Humans ; Molecular Structure ; Staphylococcal Infections/microbiology/prevention & control ; Staphylococcus aureus/*drug effects/physiology ; Time Factors ; *Ultrasonic Waves ; }, abstract = {BACKGROUND: The purpose of this study was to observe the effect of hematoporphyrin monomethyl ether (HMME)-mediated low-frequency and low-intensity ultrasound on mature and stable Staphylococcus aureus (S. aureus) biofilms under different ultrasound parameters.

METHODS: The biofilm was formed after 48-h culture with stable concentration of bacterial solution. Different types of ultrasound and time were applied to the biofilm, and the ultrasonic type and time of our experiments were determined when the biofilm was not damaged. The penetration effects of low-frequency and low-intensity ultrasound were decided by the amount of HMME that penetrated into the biofilm which was determined by fluorescence spectrometry.

RESULTS: The destruction of biofilms by pulse waveform was the strongest. Sinusoidal low-frequency and low-intensity ultrasound can enhance the biofilm permeability. For a period of time after the ultrasound was applied, the biofilm permeability increased, however, changes faded away over time.

CONCLUSIONS: Low-frequency and low-intensity sinusoidal ultrasound significantly increased the permeability of the biofilms, which was positively correlated with the time and the intensity of ultrasound. Simultaneous action of ultrasound and HMME was the most effective way to increase the permeability of the biofilms.}, } @article {pmid33092013, year = {2020}, author = {Santibañez, N and Vega, M and Pérez, T and Yáñez, A and González-Stegmaier, R and Figueroa, J and Enríquez, R and Oliver, C and Romero, A}, title = {Biofilm Produced In Vitro by Piscirickettsia salmonis Generates Differential Cytotoxicity Levels and Expression Patterns of Immune Genes in the Atlantic Salmon Cell Line SHK-1.}, journal = {Microorganisms}, volume = {8}, number = {10}, pages = {}, pmid = {33092013}, issn = {2076-2607}, support = {1171357//FONDECYT/ ; 11180994//FONDECYT/ ; 15110027//FONDAP INCAR/ ; }, abstract = {Piscirickettsia salmonis is the causative agent of Piscirickettsiosis, an infectious disease with a high economic impact on the Chilean salmonid aquaculture industry. This bacterium produces biofilm as a potential resistance and persistence strategy against stressful environmental stimuli. However, the in vitro culture conditions that modulate biofilm formation as well as the effect of sessile bacteria on virulence and immune gene expression in host cells have not been described for P. salmonis. Therefore, this study aimed to analyze the biofilm formation by P. salmonis isolates under several NaCl and iron concentrations and to evaluate the virulence of planktonic and sessile bacteria, together with the immune gene expression induced by these bacterial conditions in an Atlantic salmon macrophage cell line. Our results showed that NaCl and Fe significantly increased biofilm production in the LF-89 type strain and EM-90-like isolates. Additionally, the planktonic EM-90 isolate and sessile LF-89 generated the highest virulence levels, associated with differential expression of il-1β, il-8, nf-κb, and iκb-α genes in SHK-1 cells. These results suggest that there is no single virulence pattern or gene expression profile induced by the planktonic or sessile condition of P. salmonis, which are dependent on each strain and bacterial condition used.}, } @article {pmid33091996, year = {2021}, author = {Jingjing, E and Rongze, M and Zichao, C and Caiqing, Y and Ruixue, W and Qiaoling, Z and Zongbai, H and Ruiyin, S and Junguo, W}, title = {Improving the freeze-drying survival rate of Lactobacillus plantarum LIP-1 by increasing biofilm formation based on adjusting the composition of buffer salts in medium.}, journal = {Food chemistry}, volume = {338}, number = {}, pages = {128134}, doi = {10.1016/j.foodchem.2020.128134}, pmid = {33091996}, issn = {1873-7072}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects/*growth & development ; Buffers ; Carbon-Sulfur Lyases/genetics ; Culture Media/*chemistry ; Dose-Response Relationship, Drug ; Freeze Drying/*methods ; Homoserine/analogs & derivatives/metabolism ; Lactobacillus plantarum/cytology/*drug effects/metabolism/*physiology ; Lactones/metabolism ; Microbial Viability/*drug effects ; Quorum Sensing/drug effects ; Salts/*pharmacology ; Survival Rate ; }, abstract = {Lactic acid bacteria can improve their resistance to adverse environments through the formation of biofilm. This study found that adding different buffer salts in culture medium had a great impact on the freeze-drying survival rate of the Lactobacillus plantarum LIP-1, which could be linked to biofilm formation. Transcriptome data showed that potassium ions in buffer salt increased the expression of the luxS gene in the LuxS/autoinducer-2 (AI-2) quorum sensing system and increase synthesis of the quorum sensing signal AI-2. The AI-2 signal molecules up-regulated the cysE gene, which helps to promote biofilm formation. By adding a biofilm inhibitor, d-galactose, and performing a real-time quantitative polymerase chain reaction experiment, we found that d-galactose could down-regulated the luxS and cysE genes, reduced biofilm formation, and decreased the freeze-drying survival rate. The results of this study showed that promoting biofilm formation using appropriate buffer salts may lead to better freeze-drying survival rates.}, } @article {pmid33091849, year = {2020}, author = {Simon, G and Bérubé, C and Paquet-Côté, PA and Grenier, D and Voyer, N}, title = {Preventing Candida albicans biofilm formation using aromatic-rich piperazines.}, journal = {Bioorganic & medicinal chemistry}, volume = {28}, number = {23}, pages = {115810}, doi = {10.1016/j.bmc.2020.115810}, pmid = {33091849}, issn = {1464-3391}, mesh = {Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*physiology ; Cell Line ; Cell Survival/drug effects ; Humans ; Piperazines/chemical synthesis/*chemistry/pharmacology ; }, abstract = {The global increase in microbial resistance is an imminent threat to public health. Effective treatment of infectious diseases now requires new antimicrobial therapies. We report herein the discovery of aromatic-rich piperazines that inhibit biofilm formation by C. albicans. 22 piperazines, including 16 novel ones, were prepared efficiently using a combination of solid- and solution phase synthesis. The most potent compound prevents morphological switching under several hypha-inducing conditions and reduces C. albicans' ability to adhere to epithelial cells. These processes are essential to the development of Candida biofilms, which are associated with its increased resistance to immune defenses and antifungal agents.}, } @article {pmid33091581, year = {2020}, author = {Kannan, S and Balakrishnan, J and Govindasamy, A}, title = {Listeria monocytogens - Amended understanding of its pathogenesis with a complete picture of its membrane vesicles, quorum sensing, biofilm and invasion.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104575}, doi = {10.1016/j.micpath.2020.104575}, pmid = {33091581}, issn = {1096-1208}, mesh = {Animals ; Bacterial Proteins ; Biofilms ; Humans ; *Listeria ; *Listeria monocytogenes ; *Listeriosis ; Quorum Sensing ; }, abstract = {Listeria monocytogenes is a ubiquitous, intracellular foodborne pathogen that causes listeriosis in animals and humans. Pathogenic Listeria monocytogenes easily adapted to the conditions of human gastrointestinal tract and tolerate the counter changes such as acidity, bile, osmolarity, and antimicrobial peptides. They secrete specialized biologically active extra organ called membrane vesicles which comprises proteins, lipids, and lipopolysaccharides. Listerial vesicles possess functional versatility and play a significant role in pathogenesis by cell-free intercellular communication and toxin packaging. L. monocytogenes can attach promptly and decisively to inert substratum including intestinal mucosa, and forms biofilms and causes detrimental effects. Further, they invade the host cells through quorum sensing (QS) controlled virulence determinants and biofilms. The precise degree to which the bacterium retains the intracellular ambiance of host cells remains unknown. The machinery associated with intracellular survival, and the role of membrane vesicles, quorum sensing, and the Agr system in Listeria monocytogenes largely remains unclear. The current review focused to understand the role of membrane vesicles mediated pathogenesis biofilms, and delivers auxiliary impetus to understanding the potentials of virulence mediated invasion in Listeria monocytogenes.}, } @article {pmid33090669, year = {2021}, author = {Cascioferro, S and Carbone, D and Parrino, B and Pecoraro, C and Giovannetti, E and Cirrincione, G and Diana, P}, title = {Therapeutic Strategies To Counteract Antibiotic Resistance in MRSA Biofilm-Associated Infections.}, journal = {ChemMedChem}, volume = {16}, number = {1}, pages = {65-80}, doi = {10.1002/cmdc.202000677}, pmid = {33090669}, issn = {1860-7187}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Oxazolidinones/chemistry/pharmacology/therapeutic use ; Phenazines/chemistry/pharmacology/therapeutic use ; Protein Kinase Inhibitors/chemistry/pharmacology/therapeutic use ; Staphylococcal Infections/drug therapy/microbiology/pathology ; beta-Lactams/pharmacology/therapeutic use ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as one of the leading causes of persistent human infections. This pathogen is widespread and is able to colonize asymptomatically about a third of the population, causing moderate to severe infections. It is currently considered the most common cause of nosocomial infections and one of the main causes of death in hospitalized patients. Due to its high morbidity and mortality rate and its ability to resist most antibiotics on the market, it has been termed a "superbug". Its ability to form biofilms on biotic and abiotic surfaces seems to be the primarily means of MRSA antibiotic resistance and pervasiveness. Importantly, more than 80 % of bacterial infections are biofilm-mediated. Biofilm formation on indwelling catheters, prosthetic devices and implants is recognized as the cause of serious chronic infections in hospital environments. In this review we discuss the most relevant literature of the last five years concerning the development of synthetic small molecules able to inhibit biofilm formation or to eradicate or disperse pre-formed biofilms in the fight against MRSA diseases. The aim is to provide guidelines for the development of new anti-virulence strategies based on the knowledge so far acquired, and, to identify the main flaws of this research field, which have hindered the generation of new market-approved anti-MRSA drugs that are able to act against biofilm-associated infections.}, } @article {pmid33089285, year = {2020}, author = {Ma, J and Shao, Q and Yu, Y}, title = {[The effect of commonly used subgingival wedge-shaped defect filling materials on the formation of Porphyromonas gingivalis biofilm].}, journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology}, volume = {29}, number = {4}, pages = {375-379}, pmid = {33089285}, issn = {1006-7248}, mesh = {Biofilms ; *Dental Materials ; Glass Ionomer Cements ; Microscopy, Confocal ; *Porphyromonas gingivalis ; }, abstract = {PURPOSE: To investigate the effect of commonly used subgingival wedge-shaped defect filling materials on the formation of Porphyromonas gingivalis (P.gingivalis) biofilm.

METHODS: Subgingival class V cavities were prepared on the buccal surfaces of 48 extracted premolars. After that, the premolars were randomly divided into 3 groups (A, B and C) with 16 in each group. After filling and polishing with universal nano fluid resin, universal nano solid resin and glass ionomer cement individually, Isomet 4000 precision cutting machine was used to make specimens containing all the filling materials (mesiodistal distance: 5 mm, occlusal-gingival distance: 3 mm, buccolingual distance: 2 mm). All the specimens were placed in P.gingivalis bacterial solution for 24 hours to form P.gingivalis biofilm. Then the attachment amount of P.gingivalis was observed by crystal violet staining. Confocal laser scanning microscopy (CLSM) was used to observe the P.gingivalis biofilm. SPSS 22.0 software package was used for Kruskal-Wallis rank sum test.

RESULTS: The results of crystal violet staining showed that the amount of P.gingivalis adhered to the glass ionomer cement filling surface was significantly less than that of other groups(P<0.05). CLSM scan showed no significant difference in proportion of viable bacteria and biofilm thickness among three groups (P>0.05). P.gingivalis biofilm in glass ionomer cement group was sparse, showing small clumps, and did not aggregate into pieces. On the surface of universal nano solid resin, P.gingivalis biofilm was in large pieces with a three-dimensional structure.

CONCLUSIONS: Compared with the universal nano solid/fluid resin, the surface of glass ionomer cement is not conducive to the formation of P.gingivalis biofilm. Therefore, from the perspective of periodontal health, glass ionomer cement is suitable for filling treatment of subgingival wedge-shaped defects.}, } @article {pmid33087727, year = {2020}, author = {Klopper, KB and de Witt, RN and Bester, E and Dicks, LMT and Wolfaardt, GM}, title = {Biofilm dynamics: linking in situ biofilm biomass and metabolic activity measurements in real-time under continuous flow conditions.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {42}, pmid = {33087727}, issn = {2055-5008}, mesh = {Bacteriological Techniques/instrumentation/*methods ; Biofilms/*growth & development ; Biomass ; Carbon Dioxide ; Plankton/growth & development/microbiology ; Pseudomonas aeruginosa/metabolism/*physiology ; Spectrophotometry/instrumentation ; }, abstract = {The tools used to study biofilms generally involve either destructive, end-point analyses or periodic measurements. The advent of the internet of things (IoT) era allows circumvention of these limitations. Here we introduce and detail the development of the BioSpec; a modular, nondestructive, real-time monitoring system, which accurately and reliably track changes in biofilm biomass over time. The performance of the system was validated using a commercial spectrophotometer and produced comparable results for variations in planktonic and sessile biomass. BioSpec was combined with the previously developed carbon dioxide evolution measurement system (CEMS) to allow simultaneous measurement of biofilm biomass and metabolic activity and revealed a differential response of these interrelated parameters to changing environmental conditions. The application of this system can facilitate a greater understanding of biofilm mass-function relationships and aid in the development of biofilm control strategies.}, } @article {pmid33086880, year = {2020}, author = {Ziadi, I and El-Bassi, L and Bousselmi, L and Akrout, H}, title = {Characterization of the biofilm grown on 304L stainless steel in urban wastewaters: extracellular polymeric substances (EPS) and bacterial consortia.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {977-989}, doi = {10.1080/08927014.2020.1836163}, pmid = {33086880}, issn = {1029-2454}, mesh = {Bacteria ; *Biofilms ; Corrosion ; Extracellular Polymeric Substance Matrix ; *Stainless Steel ; Steel ; *Wastewater ; }, abstract = {Characterization of the biofilm growing on stainless steel (SS) in untreated (UTUWW) and treated (TUWW) urban wastewaters was performed. In both media, the first phase of biofilm growth was aerobic, when the genera Caldimonas, Caulobacter, Terriglobus and Edaphobacter (iron oxidizing bacteria [IOB]) and the genera Bacillus, Sulfurimonas, Syntrophobacter and Desulfobacter (sulfur oxidizing bacteria [SOB]) were identified. In the second phase, established after immersion for 7 days, the high amount of EPS inhibited the access of oxygen and promoted the growth of anaerobic bacteria, which were the genus Shewanella (iron-reducing bacterium [IRB]) and the genera Desulfovirga, Desulfovibrio, Desulfuromusa, Desulfococcus, and Desulfosarcina (sulfate-reducing bacteria [SRB]). Electrochemical measurements showed that in the first stage, the aerobic bacteria and the high amount of EPS delayed the cathodic reduction of oxygen. However, in the second stage, EPS and the anaerobic bacteria promoted anodic dissolution.}, } @article {pmid33083548, year = {2020}, author = {Chitlapilly Dass, S and Bosilevac, JM and Weinroth, M and Elowsky, CG and Zhou, Y and Anandappa, A and Wang, R}, title = {Impact of mixed biofilm formation with environmental microorganisms on E. coli O157:H7 survival against sanitization.}, journal = {NPJ science of food}, volume = {4}, number = {}, pages = {16}, pmid = {33083548}, issn = {2396-8370}, abstract = {Biofilm formation by foodborne pathogens is a serious threat to food safety and public health. Meat processing plants may harbor various microorganisms and occasional foodborne pathogens; thus, the environmental microbial community might impact pathogen survival via mixed biofilm formation. We collected floor drain samples from two beef plants with different E. coli O157:H7 prevalence history and investigated the effects of the environmental microorganisms on pathogen sanitizer tolerance. The results showed that biofilm forming ability and bacterial species composition varied considerably based on the plants and drain locations. E. coli O157:H7 cells obtained significantly higher sanitizer tolerance in mixed biofilms by samples from the plant with recurrent E. coli O157:H7 prevalence than those mixed with samples from the other plant. The mixed biofilm that best protected E. coli O157:H7 also had the highest species diversity. The percentages of the species were altered significantly after sanitization, suggesting that the community composition affects the role and tolerance level of each individual species. Therefore, the unique environmental microbial community, their ability to form biofilms on contact surfaces and the interspecies interactions all play roles in E. coli O157:H7 persistence by either enhancing or reducing pathogen survival within the biofilm community.}, } @article {pmid33082254, year = {2020}, author = {Afonina, I and Ong, J and Chua, J and Lu, T and Kline, KA}, title = {Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis.}, journal = {mBio}, volume = {11}, number = {5}, pages = {}, pmid = {33082254}, issn = {2150-7511}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; *CRISPR-Cas Systems ; Enterococcus faecalis/*genetics/*physiology ; Genes, Essential ; }, abstract = {Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication.IMPORTANCEEnterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology.}, } @article {pmid33082251, year = {2020}, author = {Klementiev, AD and Jin, Z and Whiteley, M}, title = {Micron Scale Spatial Measurement of the O2 Gradient Surrounding a Bacterial Biofilm in Real Time.}, journal = {mBio}, volume = {11}, number = {5}, pages = {}, pmid = {33082251}, issn = {2150-7511}, support = {F31 DE029415/DE/NIDCR NIH HHS/United States ; R01 GM116547/GM/NIGMS NIH HHS/United States ; }, mesh = {Anaerobiosis ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Ciprofloxacin/pharmacology ; Electrochemical Techniques ; Oxygen/*analysis ; Pseudomonas aeruginosa/drug effects/*physiology ; }, abstract = {Bacteria alter their local chemical environment through both consumption and the production of a variety of molecules, ultimately shaping the local ecology. Molecular oxygen (O2) is a key metabolite that affects the physiology and behavior of virtually all bacteria, and its consumption often results in O2 gradients within sessile bacterial communities (biofilms). O2 plays a critical role in several bacterial phenotypes, including antibiotic tolerance; however, our understanding of O2 levels within and surrounding biofilms has been hampered by the difficulties in measuring O2 levels in real-time for extended durations and at the micron scale. Here, we developed electrochemical methodology based on scanning electrochemical microscopy to quantify the O2 gradients present above a Pseudomonas aeruginosa biofilm. These results reveal that a biofilm produces a hypoxic zone that extends hundreds of microns from the biofilm surface within minutes and that the biofilm consumes O2 at a maximum rate. Treating the biofilm with levels of the antibiotic ciprofloxacin that kill 99% of the bacteria did not affect the O2 gradient, indicating that the biofilm is highly resilient to antimicrobial treatment in regard to O2 consumption.IMPORTANCE O2 is a fundamental environmental metabolite that affects all life on earth. While toxic to many microbes and obligately required by others, those that have appropriate physiological responses survive and can even benefit from various levels of O2, particularly in biofilm communities. Although most studies have focused on measuring O2 within biofilms, little is known about O2 gradients surrounding biofilms. Here, we developed electrochemical methodology based on scanning electrochemical microscopy to measure the O2 gradients surrounding biofilms in real time on the micron scale. Our results reveal that P. aeruginosa biofilms produce a hypoxic zone that can extend hundreds of microns from the biofilm surface and that this gradient remains even after the addition of antibiotic concentrations that eradicated 99% of viable cells. Our results provide a high resolution of the O2 gradients produced by P. aeruginosa biofilms and reveal sustained O2 consumption in the presence of antibiotics.}, } @article {pmid33081846, year = {2020}, author = {Bowler, P and Murphy, C and Wolcott, R}, title = {Biofilm exacerbates antibiotic resistance: Is this a current oversight in antimicrobial stewardship?.}, journal = {Antimicrobial resistance and infection control}, volume = {9}, number = {1}, pages = {162}, pmid = {33081846}, issn = {2047-2994}, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Stewardship/*methods ; Biofilms/*growth & development ; Cross Infection/drug therapy/*prevention & control ; *Drug Resistance, Microbial ; Gene Transfer, Horizontal ; Humans ; Mutation ; }, abstract = {OBJECTIVE: To raise awareness of the role of environmental biofilm in the emergence and spread of antibiotic resistance and its consideration in antimicrobial stewardship.

BACKGROUND: Antibiotic resistance is a major threat to public health. Overuse of antibiotics, increased international travel, and genetic promiscuity amongst bacteria have contributed to antibiotic resistance, and global containment efforts have so far met with limited success. Antibiotic resistance is a natural mechanism by which bacteria have adapted to environmental threats over billions of years and is caused either by genetic mutations or by horizontal gene transfer. Another ancient survival strategy involves bacteria existing within a self-produced polymeric matrix, which today is termed biofilm. Biofilm similarly enables bacterial tolerance to environmental threats, and also encourages the transfer of antibiotic resistance genes between bacterial species. This natural and ubiquitous mode of bacterial life has not been considered amongst strategies to tackle antibiotic resistance in healthcare facilities, despite its ability to significantly enhance bacterial survival and persistence, and to encourage antibiotic resistance.

CONCLUSION: Biofilm must be considered synonymously with antibiotic resistance because of its proficiency in transferring resistance genes as well as its innate phenotypic tolerance to antibiotics. Although biofilm falls outside of the current definition of antimicrobial stewardship, greater awareness of the existence, ubiquity, and consequences of environmental biofilm amongst healthcare practitioners is crucial to improving hygiene practices and controlling the emergence and spread of antibiotic resistance in healthcare facilities.}, } @article {pmid33081309, year = {2020}, author = {Balabanova, L and Shkryl, Y and Slepchenko, L and Cheraneva, D and Podvolotskaya, A and Bakunina, I and Nedashkovskaya, O and Son, O and Tekutyeva, L}, title = {Genomic Features of a Food-Derived Pseudomonas aeruginosa Strain PAEM and Biofilm-Associated Gene Expression under a Marine Bacterial α-Galactosidase.}, journal = {International journal of molecular sciences}, volume = {21}, number = {20}, pages = {}, pmid = {33081309}, issn = {1422-0067}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cold Shock Proteins and Peptides/genetics/metabolism ; *Food Microbiology ; *Genes, Bacterial ; Meat Products/microbiology ; Pseudomonas aeruginosa/*genetics/isolation & purification/physiology ; Quorum Sensing ; alpha-Galactosidase/genetics/metabolism ; }, abstract = {The biofilm-producing strains of P. aeruginosa colonize various surfaces, including food products and industry equipment that can cause serious human and animal health problems. The biofilms enable microorganisms to evolve the resistance to antibiotics and disinfectants. Analysis of the P. aeruginosa strain (serotype O6, sequence type 2502), isolated from an environment of meat processing (PAEM) during a ready-to-cook product storage (-20 °C), showed both the mosaic similarity and differences between free-living and clinical strains by their coding DNA sequences. Therefore, a cold shock protein (CspA) has been suggested for consideration of the evolution probability of the cold-adapted P. aeruginosa strains. In addition, the study of the action of cold-active enzymes from marine bacteria against the food-derived pathogen could contribute to the methods for controlling P. aeruginosa biofilms. The genes responsible for bacterial biofilm regulation are predominantly controlled by quorum sensing, and they directly or indirectly participate in the synthesis of extracellular polysaccharides, which are the main element of the intercellular matrix. The levels of expression for 14 biofilm-associated genes of the food-derived P. aeruginosa strain PAEM in the presence of different concentrations of the glycoside hydrolase of family 36, α-galactosidase α-PsGal, from the marine bacterium Pseudoalteromonas sp. KMM 701 were determined. The real-time PCR data clustered these genes into five groups according to the pattern of positive or negative regulation of their expression in response to the action of α-galactosidase. The results revealed a dose-dependent mechanism of the enzymatic effect on the PAEM biofilm synthesis and dispersal genes.}, } @article {pmid33080907, year = {2020}, author = {Olar, R and Badea, M and Maxim, C and Grumezescu, AM and Bleotu, C and Măruţescu, L and Chifiriuc, MC}, title = {Anti-biofilm Fe3O4@C18-[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate Derivative Core-shell Nanocoatings.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {20}, pages = {}, pmid = {33080907}, issn = {1996-1944}, support = {PDI-PFE-CDI ID 335//Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii/ ; PCCDI/2018 no. 52//Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii/ ; CNFIS-FDI-2020-0355//Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii/ ; }, abstract = {The derivatives 5,7-dimethyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (1) and 7-methyl-5-phenyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (2) were fully characterized by single-crystal X-ray diffraction. Their supramolecular structure is built through both π-π stacking and C=S-π interactions for both compounds. The embedment of the tested compounds into Fe3O4@C18 core-shell nanocoatings increased the protection degree against Candida albicans biofilms on the catheter surface, suggesting that these bioactive nanocoatings could be further developed as non-cytotoxic strategies for fighting biofilm-associated fungal infections.}, } @article {pmid33080455, year = {2021}, author = {Liang, D and He, W and Li, C and Wang, F and Crittenden, JC and Feng, Y}, title = {Remediation of nitrate contamination by membrane hydrogenotrophic denitrifying biofilm integrated in microbial electrolysis cell.}, journal = {Water research}, volume = {188}, number = {}, pages = {116498}, doi = {10.1016/j.watres.2020.116498}, pmid = {33080455}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Electrolysis ; Membranes ; *Nitrates ; Nitrogen ; RNA, Ribosomal, 16S ; }, abstract = {Complete biological denitrification is usually restricted in electron donor lacking waters. Hydrogenotrophic denitrification attracts attention for its clean and cost-efficiency advantages. Therein, the hydrogen could be effectively generated by microbial electrolysis cells (MECs) from organic wastes. In this study, a gas diffusion membrane (GDM) integrated MEC (MMEC) was constructed and provided a novel non-polluting approach for nitrate contaminated water remediation, in which the hydrogen was recovered from substrate degradation in anode and diffused across GDM as electron donor for denitrification. The high overall nitrogen removal of 91 ± 0.1%-95 ± 1.9% and 90 ± 1.6%-94 ± 2.2% were respectively achieved in Ti-MMEC and SS-MMEC with titanium and stainless-steel mesh as cathode at all applied voltages (0.4-0.8 V). Decreasing applied voltage from 0.8 to 0.4 V significantly improved the electron utilization efficiency for denitrification from 26 ± 3.6% to 73 ± 0.1% in Ti-MMEC. Integrating MEC with GDM greatly improved TN removal by 40% under applied voltage of 0.8 V. The hydrogenotrophic denitrifiers of Rhodocyclaceae, Paracoccus, and Dethiobacter, dominated in MMECs facilitating TN removal. Functional denitrification related genes including napAB, nirKS, norBC and nosZ predicted by PICRUSt2 based on 16S rRNA gene data demonstrated higher abundance in MMECs.}, } @article {pmid33080087, year = {2021}, author = {Rajasekharan, SK and Paz-Aviram, T and Galili, S and Berkovich, Z and Reifen, R and Shemesh, M}, title = {Biofilm formation onto starch fibres by Bacillus subtilis governs its successful adaptation to chickpea milk.}, journal = {Microbial biotechnology}, volume = {14}, number = {4}, pages = {1839-1846}, pmid = {33080087}, issn = {1751-7915}, support = {//Agricultural Research Organisation/ ; }, mesh = {*Bacillus subtilis/genetics/growth & development ; Bacterial Proteins/genetics ; *Biofilms ; *Cicer/chemistry ; Starch ; }, abstract = {Beneficial biofilms may confer effective adaptation to food matrices that assist bacteria in enduring hostile environmental conditions. The matrices, for instance, dietary fibres of various food products, might serve as a natural scaffold for bacterial cells to adhere and grow as biofilms. Here, we report on a unique interaction of Bacillus subtilis cells with the resistant starch fibresof chickpea milk (CPM), herein CPM fibres, along with the production of a reddish-pink pigment. Genetic analysis identified the pigment as pulcherrimin, and also revealed the involvement of Spo0A/SinI pathway in modulating the observed phenotypes. Besides, through successful colonization of the CPM fibres, the wild-type cells of B. subtilis displayed enhanced survivability and resilience to environmental stress, such as heat and in vitro gastrointestinal treatments. In total, we infer that the biofilm formation on CPM fibres is an adaptation response of B. subtilis for strategic survival.}, } @article {pmid33080080, year = {2022}, author = {Muras, A and Mallo, N and Otero-Casal, P and Pose-Rodríguez, JM and Otero, A}, title = {Quorum sensing systems as a new target to prevent biofilm-related oral diseases.}, journal = {Oral diseases}, volume = {28}, number = {2}, pages = {307-313}, doi = {10.1111/odi.13689}, pmid = {33080080}, issn = {1601-0825}, support = {ED431B 2020/13//Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia/ ; ED481A-2015/311//Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia/ ; }, mesh = {Bacteria/genetics ; Biofilms ; *Ecosystem ; *Quorum Sensing/physiology ; }, abstract = {OBJECTIVE: The present study summarizes the current knowledge on the role of bacterial extracellular signaling systems, known as quorum sensing (QS), in oral biofilm formation, and on the possibility of blocking these microbial communication systems as a potential approach to prevent and treat oral infectious diseases.

METHODS: A detailed literature review of the current knowledge of QS in the oral cavity was performed, using the databases MEDLINE (through PubMed) and Web of Science.

RESULTS: Accumulating direct and indirect evidence indicates an important role of QS molecules in the oral microbial ecosystem.

CONCLUSIONS: The mechanisms regulating gene expression through bacterial communication systems constitute a promising target to control oral biofilm formation. Although cell-to-cell communication is pivotal for biofilm formation of many pathogenic bacteria, knowledge concerning microbial interactions and signaling processes within multispecies biofilms in the oral cavity is still limited.}, } @article {pmid33079548, year = {2020}, author = {Yang, S and Tran, C and Whiteley, GS and Glasbey, T and Kriel, FH and McKenzie, DR and Manos, J and Das, T}, title = {Covalent Immobilization of N-Acetylcysteine on a Polyvinyl Chloride Substrate Prevents Bacterial Adhesion and Biofilm Formation.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {36}, number = {43}, pages = {13023-13033}, doi = {10.1021/acs.langmuir.0c02414}, pmid = {33079548}, issn = {1520-5827}, mesh = {*Acetylcysteine/pharmacology ; Animals ; Anti-Bacterial Agents/toxicity ; *Bacterial Adhesion ; Biofilms ; Gram-Positive Bacteria ; Humans ; Polyvinyl Chloride ; }, abstract = {Biofilm formation and antimicrobial resistance at surgical implant sites result in high morbidity and mortality. Identifying novel molecules that inhibit biofilm formation to coat surgical biomaterials is essential. One such compound is N-acetylcysteine (NAC), a potent antioxidant precursor for glutathione, necessary in mammalian cells and known to disrupt/prevent biofilms. In this study, NAC was covalently immobilized onto functionalized polyvinyl chloride surfaces using plasma immersion ion implantation (PIII) treatment that achieves covalent binding without the need for linker groups. NAC immobilization was characterized using water contact angles, Fourier-transform infrared, and X-ray photoelectron spectroscopy techniques. Bacterial viability and biofilm formation on NAC surfaces were assessed using resazurin assays, phase contrast microscopy, and colony counting experiments. Effect of NAC on bacterial polysaccharide production and DNA cleaving was investigated using the phenol-sulfuric acid method and the Qubit fluorometer. Surface thermodynamics between the NAC coating and bacterial cells were measured using the Lewis acid-base method. Surface characterization techniques demonstrated superficial changes after PIII treatment and subsequent covalent NAC immobilization. NAC-coated surfaces significantly reduced biofilm viability and the presence of Gram-negative and Gram-positive bacteria. NAC also decreased polysaccharide production and degraded DNA. This led to unfavorable conditions for biofilm formation on NAC-coated surfaces, as demonstrated by surface thermodynamic analysis. NAC-coated surfaces showed no cytotoxicity to human fibroblast cells. This study has successfully utilized NAC as an antibiofilm coating, which may pave the way for improved prophylactic coatings on medical implant devices in the future.}, } @article {pmid33078643, year = {2020}, author = {Bianchera, A and Buttini, F and Bettini, R}, title = {Micro/nanosystems and biomaterials for controlled delivery of antimicrobial and anti-biofilm agents.}, journal = {Expert opinion on therapeutic patents}, volume = {30}, number = {12}, pages = {983-1000}, doi = {10.1080/13543776.2020.1839415}, pmid = {33078643}, issn = {1744-7674}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/pharmacology ; Biocompatible Materials/chemistry ; Biofilms/*drug effects ; *Drug Delivery Systems ; Drug Development ; Drug Resistance, Bacterial ; Humans ; Nanoparticles ; Patents as Topic ; Respiratory Tract Infections/drug therapy/microbiology ; Wound Infection/drug therapy/microbiology ; }, abstract = {INTRODUCTION: Microbial resistance is a severe problem for clinical practice due to misuse of antibiotics that promotes the development of surviving strategies by bacteria and fungi. Microbial cells surrounded by a self-produced polymer matrix, defined as biofilms, are inherently more difficult to eradicate. Biofilms endow bacteria with a unique resistance against antibiotics and other anti-microbial agents and play a crucial role in chronic infection.

AREAS COVERED: Biofilm-associated antimicrobial resistance in the lung and wounds. Existing inhaled therapies for treatment of biofilm-associated lung infections. Role of pharmaceutical nanotechnologies to fight resistant microbes and biofilms.

EXPERT OPINION: The effectiveness of antibiotics has gradually decreased due to the onset of resistance phenomena. The formation of biofilms represents one of the most important steps in the development of resistance to antimicrobial treatment. The most obvious solution for overcoming this criticality would be the discovery of new antibiotics. However, the number of new molecules with antimicrobial activity brought into clinical development has considerably decreased. In the last decades the development of innovative drug delivery systems, in particular those based on nanotechnological platforms, has represented the most effective and economically affordable approach to optimize the use of available antibiotics, improving their effectiveness profile. Abbreviations AZT: Aztreonam; BAT: Biofilm antibiotic tolerance; CF: Cystic Fibrosis; CIP: Ciprofloxacin; CRS: Chronic Rhinosinusitis; DPPG: 1,2-dipalmytoyl-sn-glycero-3-phosphoglycerol; DSPC: 1,2-distearoyl-sn-glycero-phosphocholine sodium salt; EPS: extracellular polymeric substance; FEV1: Forced Expiratory Volume in the first second; GSNO: S-nitroso-glutathione; LAE: lauroyl arginate ethyl; MIC: Minimum inhibitory Concentration; NCFB: Non-Cystic Fibrosis Bronchiectasis; NTM: Non-Tuberculous Mycobacteria; NTM-LD: Non-tuberculous mycobacteria Lung Disease PA: Pseudomonas aeruginosa; pDMAEMA: poly(dimethylaminoethyl methacrylate);pDMAEMA-co-PAA-co-BMA: poly(dimethylaminoethyl methacrylate)-co-propylacrylic acid-co-butyl methacrylate; PEG: polyethylene glycol; PEGDMA: polyethylene glycol dimethacrylate;PCL: Poly-ε-caprolactone; PLA: poly-lactic acid; PLGA: poly-lactic-co-glycolic acid; PVA: poli-vinyl alcohol; SA: Staphylococcus aureus; TIP: Tobramycin Inhalation Powder; TIS: Tobramycin Inhalation Solution; TPP: Tripolyphosphate.}, } @article {pmid33078624, year = {2020}, author = {Afonso, TB and Simões, LC and Lima, N}, title = {Effect of quorum sensing and quenching molecules on inter-kingdom biofilm formation by Penicillium expansum and bacteria.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {965-976}, doi = {10.1080/08927014.2020.1836162}, pmid = {33078624}, issn = {1029-2454}, mesh = {4-Butyrolactone ; Biofilms ; Methylobacterium ; Penicillium ; *Quorum Sensing ; }, abstract = {The ecology of a biofilm is a complex function of different factors, including the presence of microbial metabolites excreted by the inhabitants of the biofilm. This study aimed to assess the effect of patulin, and N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) on inter-kingdom biofilm formation between a filamentous fungus and bacteria isolated from drinking water. The filamentous fungus Penicillium expansum and the bacteria Acinetobacter calcoaceticus and Methylobacterium oryzae were used as model species. M. oryzae biofilm formation and development was more susceptible to the presence of the quenching molecules than A. calcoaceticus biofilms. Patulin reduced M. oryzae biofilm growth while 3-oxo-C12-HSL caused an increase after 48 h. The presence of P. expansum had a detrimental effect on M. oryzae cell numbers, while an advantageous effect was observed with A. calcoaceticus. The overall results reveal that quorum sensing and quenching molecules have a significant effect on inter-kingdom biofilm formation, especially on bacterial numbers.}, } @article {pmid33077828, year = {2021}, author = {Wang, Y and Xiong, Y and Wang, Z and Zheng, J and Xu, G and Deng, Q and Wen, Z and Yu, Z}, title = {Comparison of solithromycin with erythromycin in Enterococcus faecalis and Enterococcus faecium from China: antibacterial activity, clonality, resistance mechanism, and inhibition of biofilm formation.}, journal = {The Journal of antibiotics}, volume = {74}, number = {2}, pages = {143-151}, pmid = {33077828}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; China ; Cross Infection/microbiology ; Drug Resistance, Bacterial/drug effects/genetics ; Enterococcus faecalis/*drug effects ; Enterococcus faecium/*drug effects ; Erythromycin/*pharmacology ; Linezolid/pharmacology ; Macrolides/*pharmacology ; Microbial Sensitivity Tests ; Triazoles/*pharmacology ; Vancomycin/pharmacology ; }, abstract = {Solithromycin (SOL), a fourth-generation macrolide and ketolide, has been reported to have robust antibacterial activity against a wide spectrum of Gram-positive bacteria. However, the impact of SOL on planktonic growth and biofilm formation of clinical enterococcus isolates remains unclear. In this study, 276 Enterococcus faecalis isolates and 122 Enterococcus faecium were retrospectively collected from a tertiary hospital from China. SOL against clinical isolates of enterococci from China were evaluated the antimicrobial activity in comparison with erythromycin, and explore its relationship with the clonality, virulence genes and resistance mechanism of these isolates. Our data showed that the MICs of SOL against clinical E. faecalis and E. faecium isolates from China were ≤4 and ≤8 mg l[-1], respectively. ST16 and ST179 were regarded as the risk factor to SOL resistance in E. faecalis. SOL could inhibit but not eradicate the biofilm formation of E. faecalis. The bactericidal effects of SOL against E. faecalis and E. faecium were demonstrated to be similar to linezolid and vancomycin using time-kill assays. In conclusion, SOL showed significantly enhanced antibacterial activity against clinical isolates of E. faecalis and E. faecium from China in comparison to erythromycin. Furthermore, SOL could inhibit the biofilm formation of E. faecalis and have the similar bactericidal ability as linezolid and vancomycin against both E. faecalis and E. faecium.}, } @article {pmid33077360, year = {2021}, author = {Gu, Y and Tian, J and Zhang, Y and Wu, R and Li, L and Zhang, B and He, Y}, title = {Dissecting signal molecule AI-2 mediated biofilm formation and environmental tolerance in Lactobacillus plantarum.}, journal = {Journal of bioscience and bioengineering}, volume = {131}, number = {2}, pages = {153-160}, doi = {10.1016/j.jbiosc.2020.09.015}, pmid = {33077360}, issn = {1347-4421}, mesh = {Biofilms/*growth & development ; *Environment ; Homoserine/*analogs & derivatives/metabolism ; Lactobacillus plantarum/cytology/metabolism/*physiology ; Lactones/*metabolism ; Quorum Sensing ; }, abstract = {Quorum sensing (QS) exists in bacteria to communicate with each other and regulate group behaviors in a cell density-dependent manner, which uses signal molecule autoinducer-2 (AI-2) to intra- and inter-species communication. Effects of exogenous AI-2 on biofilm formation and environmental tolerance in Lactobacillus plantarum are the focus of this review. The responses to the exogenous AI-2 cross multiple physiological metabolic behaviors involving the bacteria growth, morphological characterization, biofilm development, extracellular polysaccharides (EPS) amount and related genes expression as well as the environmental stresses tolerance. The cell surface was smoother in the AI-2 supplemented treatments than without AI-2. Meanwhile, AI-2 had ability to promote the growth and formation of biofilm by increasing the yield of EPS, the main components of biofilm. The changes in lamC and ftsH gene expression point to altered regulation for hydrolysis process of polysaccharides as well as the potential for enhanced biofilm formation. The presence of AI-2 also significantly improved (p < 0.01) the tolerance of bile salts in L. plantarum, but the same results did not appear in acid tolerance. In conclusion, AI-2 supplementation could improve the biofilm formation and bile salts tolerance in L. plantarum, and this effect was likely modulated by facilitating EPS production and suppression polysaccharides hydrolysis.}, } @article {pmid33075880, year = {2020}, author = {Kosztołowicz, T and Metzler, R}, title = {Diffusion of antibiotics through a biofilm in the presence of diffusion and absorption barriers.}, journal = {Physical review. E}, volume = {102}, number = {3-1}, pages = {032408}, doi = {10.1103/PhysRevE.102.032408}, pmid = {33075880}, issn = {2470-0053}, mesh = {*Absorption, Physicochemical ; Animals ; Anti-Bacterial Agents/*metabolism/pharmacology ; *Biofilms ; Diffusion ; *Models, Biological ; Proteus mirabilis/drug effects/metabolism/physiology ; }, abstract = {We propose a model of antibiotic diffusion through a bacterial biofilm when diffusion and/or absorption barriers develop in the biofilm. The idea of this model is: We deduce details of the diffusion process in a medium in which direct experimental study is difficult, based on probing diffusion in external regions. Since a biofilm has a gel-like consistency, we suppose that subdiffusion of particles in the biofilm may occur. To describe this process we use a fractional subdiffusion-absorption equation with an adjustable anomalous diffusion exponent. The boundary conditions at the boundaries of the biofilm are derived by means of a particle random walk model on a discrete lattice leading to an expression involving a fractional time derivative. We show that the temporal evolution of the total amount of substance that has diffused through the biofilm explicitly depends on whether there is antibiotic absorption in the biofilm. This fact is used to experimentally check for antibiotic absorption in the biofilm and if subdiffusion and absorption parameters of the biofilm change over time. We propose a four-stage model of antibiotic diffusion in biofilm based on the following physical characteristics: whether there is absorption of the antibiotic in the biofilm and whether all biofilm parameters remain unchanged over time. The biological interpretation of the stages, in particular their relation with the bacterial defense mechanisms, is discussed. Theoretical results are compared with empirical results of ciprofloxacin diffusion through Pseudomonas aeruginosa biofilm, and ciprofloxacin and gentamicin diffusion through Proteus mirabilis biofilm.}, } @article {pmid33075739, year = {2020}, author = {Dolid, A and Gomes, LC and Mergulhão, FJ and Reches, M}, title = {Combining chemistry and topography to fight biofilm formation: Fabrication of micropatterned surfaces with a peptide-based coating.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {196}, number = {}, pages = {111365}, doi = {10.1016/j.colsurfb.2020.111365}, pmid = {33075739}, issn = {1873-4367}, mesh = {*Bacterial Adhesion ; Biofilms ; *Biofouling/prevention & control ; Peptides/pharmacology ; Staphylococcus epidermidis ; Surface Properties ; }, abstract = {This paper describes the fabrication of antifouling surfaces by the combination of topography and peptide chemistry. The topography of the surface mimics the skin of the shark that can resist biofouling by having a certain microtopography. A peptide-based coating that resists fouling self-assembles on these surfaces. In biofilm formation assays, performed under static conditions, the resulting combination (micropattern with peptide coating) has superior antifouling properties against the Gram-negative and Gram-positive strains tested (Escherichia coli and Staphylococcus epidermidis, respectively) when compared to both micropatterned and peptide-coated surfaces. The same behavior was observed in dynamic assays performed in a parallel plate flow chamber (PPFC) setup, where E. coli could not attach to the micropatterned surface coated with peptide during the 30 min of initial adhesion. These assays, mimicking physiological shear stress conditions, suggest that the peptide-coated surface with micropatterned topography may be promising in reducing adhesion and subsequent biofilm formation in biomedical devices such as urinary catheters and stents, and cardiovascular, dental and orthopedic implants.}, } @article {pmid33073153, year = {2020}, author = {Lam, AK and Moen, EL and Pusavat, J and Wouters, CL and Panlilio, H and Ferrell, MJ and Houck, MB and Glatzhofer, DT and Rice, CV}, title = {PEGylation of Polyethylenimine Lowers Acute Toxicity while Retaining Anti-Biofilm and β-Lactam Potentiation Properties against Antibiotic-Resistant Pathogens.}, journal = {ACS omega}, volume = {5}, number = {40}, pages = {26262-26270}, pmid = {33073153}, issn = {2470-1343}, support = {P20 GM103640/GM/NIGMS NIH HHS/United States ; R03 AI142420/AI/NIAID NIH HHS/United States ; }, abstract = {Bacterial biofilms, often impenetrable to antibiotic medications, are a leading cause of poor wound healing. The prognosis is worse for wounds with biofilms of antimicrobial-resistant (AMR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and multi-drug resistant Pseudomonas aeruginosa (MDR-PA). Resistance hinders initial treatment of standard-of-care antibiotics. The persistence of MRSA, MRSE, and/or MDR-PA often allows acute infections to become chronic wound infections. The water-soluble hydrophilic properties of low-molecular-weight (600 Da) branched polyethylenimine (600 Da BPEI) enable easy drug delivery to directly attack AMR and biofilms in the wound environment as a topical agent for wound treatment. To mitigate toxicity issues, we have modified 600 Da BPEI with polyethylene glycol (PEG) in a straightforward one-step reaction. The PEG-BPEI molecules disable β-lactam resistance in MRSA, MRSE, and MDR-PA while also having the ability to dissolve established biofilms. PEG-BPEI accomplishes these tasks independently, resulting in a multifunction potentiation agent. We envision wound treatment with antibiotics given topically, orally, or intravenously in which external application of PEG-BPEIs disables biofilms and resistance mechanisms. In the absence of a robust pipeline of new drugs, existing drugs and regimens must be re-evaluated as combination(s) with potentiators. The PEGylation of 600 Da BPEI provides new opportunities to meet this goal with a single compound whose multifunction properties are retained while lowering acute toxicity.}, } @article {pmid33073086, year = {2020}, author = {Venkatramanan, M and Sankar Ganesh, P and Senthil, R and Akshay, J and Veera Ravi, A and Langeswaran, K and Vadivelu, J and Nagarajan, S and Rajendran, K and Shankar, EM}, title = {Inhibition of Quorum Sensing and Biofilm Formation in Chromobacterium violaceum by Fruit Extracts of Passiflora edulis.}, journal = {ACS omega}, volume = {5}, number = {40}, pages = {25605-25616}, pmid = {33073086}, issn = {2470-1343}, abstract = {Chromobacterium violaceum (C. violaceum) is a Gram-negative, rod-shaped facultatively anaerobic bacterium implicated with recalcitrant human infections. Here, we evaluated the anti-QS and antibiofilm activities of ethyl acetate extracts of Passiflora edulis (P. edulis) on the likely inactivation of acyl-homoserine lactone (AHL)-regulated molecules in C. violaceum both by in vitro and in silico analyses. Our investigations showed that the sub-MIC levels were 2, 1, and 0.5 mg/mL, and the concentrations showed a marked reduction in violacein pigment production by 75.8, 64.6, and 35.2%. AHL quantification showed 72.5, 52.2, and 35.9% inhibitions, inhibitions of EPS production (72.8, 36.5, and 25.9%), and reductions in biofilm formation (90.7, 69.4, and 51.8%) as compared to a control. Light microscopy and CLSM analysis revealed dramatic reduction in the treated biofilm group as compared to the control. GC-MS analysis showed 20 major peaks whose chemical structures were docked as the CviR ligand. The highest docking score was observed for hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester bonds in the active site of CviR with a binding energy of -8.825 kcal/mol. Together, we found that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester remarkably interacted with CviR to inhibit the QS system. Hence, we concluded that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester of P. edulis could likely be evaluated for treating C. violaceum infections.}, } @article {pmid33072039, year = {2020}, author = {Salzer, A and Keinhörster, D and Kästle, C and Kästle, B and Wolz, C}, title = {Small Alarmone Synthetases RelP and RelQ of Staphylococcus aureus Are Involved in Biofilm Formation and Maintenance Under Cell Wall Stress Conditions.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {575882}, pmid = {33072039}, issn = {1664-302X}, abstract = {The stringent response is characterized by the synthesis of the alarmone (p)ppGpp. The phenotypic consequences resulting from (p)ppGpp accumulation vary among species, and for several pathogenic bacteria, it has been shown that the activation of the stringent response strongly affects biofilm formation and maintenance. In Staphylococcus aureus, (p)ppGpp can be synthesized by the RelA/SpoT homolog Rel upon amino acid deprivation or by the two small alarmone synthetases RelP and RelQ under cell wall stress. We found that relP and relQ increase biofilm formation under cell wall stress conditions induced by a subinhibitory vancomycin concentration. However, the effect of (p)ppGpp on biofilm formation is independent of the regulators CodY and Agr. Biofilms formed by the strain HG001 or its (p)ppGpp-defective mutants are mainly composed of extracellular DNA and proteins. Furthermore, the induction of the RelPQ-mediated stringent response contributes to biofilm-related antibiotic tolerance. The proposed (p)ppGpp-inhibiting peptide DJK-5 shows bactericidal and biofilm-inhibitory activity. However, a non-(p)ppGpp-producing strain is even more vulnerable to DJK-5. This strongly argues against the assumption that DJK-5 acts via (p)ppGpp inhibition. In summary, RelP and RelQ play a major role in biofilm formation and maintenance under cell wall stress conditions.}, } @article {pmid33072035, year = {2020}, author = {Kreienbaum, M and Dörrich, AK and Brandt, D and Schmid, NE and Leonhard, T and Hager, F and Brenzinger, S and Hahn, J and Glatter, T and Ruwe, M and Briegel, A and Kalinowski, J and Thormann, KM}, title = {Isolation and Characterization of Shewanella Phage Thanatos Infecting and Lysing Shewanella oneidensis and Promoting Nascent Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {573260}, pmid = {33072035}, issn = {1664-302X}, abstract = {Species of the genus Shewanella are widespread in nature in various habitats, however, little is known about phages affecting Shewanella sp. Here, we report the isolation of phages from diverse freshwater environments that infect and lyse strains of Shewanella oneidensis and other Shewanella sp. Sequence analysis and microscopic imaging strongly indicate that these phages form a so far unclassified genus, now named Shewanella phage Thanatos, which can be positioned within the subfamily of Tevenvirinae (Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes; Caudovirales; Myoviridae; Tevenvirinae). We characterized one member of this group in more detail using S. oneidensis MR-1 as a host. Shewanella phage Thanatos-1 possesses a prolate icosahedral capsule of about 110 nm in height and 70 nm in width and a tail of about 95 nm in length. The dsDNA genome exhibits a GC content of about 34.5%, has a size of 160.6 kbp and encodes about 206 proteins (92 with an annotated putative function) and two tRNAs. Out of those 206, MS analyses identified about 155 phage proteins in PEG-precipitated samples of infected cells. Phage attachment likely requires the outer lipopolysaccharide of S. oneidensis, narrowing the phage's host range. Under the applied conditions, about 20 novel phage particles per cell were produced after a latent period of approximately 40 min, which are stable at a pH range from 4 to 12 and resist temperatures up to 55°C for at least 24 h. Addition of Thanatos to S. oneidensis results in partial dissolution of established biofilms, however, early exposure of planktonic cells to Thanatos significantly enhances biofilm formation. Taken together, we identified a novel genus of Myophages affecting S. oneidensis communities in different ways.}, } @article {pmid33072026, year = {2020}, author = {Liu, X and Zhang, K and Liu, Y and Zou, D and Wang, D and Xie, Z}, title = {Effects of Calcium and Signal Sensing Systems on Azorhizobium caulinodans Biofilm Formation and Host Colonization.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {563367}, pmid = {33072026}, issn = {1664-302X}, abstract = {Biofilm formation is important for establishing plants-microbe associations. The role of calcium on biofilm formation has been studied in many bacteria except rhizobia. In this study, we investigated the role of calcium for biofilm formation in Azorhizobium caulindans, which forms nodules in the stem and root of its host plant Sesbania rostrata. We found that calcium is essential for A. caulindans biofilm formation, in addition to the presence of extracellular matrix components, eDNA and proteins. Also, calcium-mediated biofilm formation was tested with chemotaxis, motility, cyclic di-GMP synthesis, and quorum sensing mutants. Finally, calcium was found to promote S. rostrata root colonization of A. caulinodans. In total, these results show that calcium is essential for A. caulindans biofilm formation, and it affects the interaction between A. caulinodans and host plant.}, } @article {pmid33068987, year = {2021}, author = {Li, Z and Dai, R and Yang, B and Chen, M and Wang, X and Wang, Z}, title = {An electrochemical membrane biofilm reactor for removing sulfonamides from wastewater and suppressing antibiotic resistance development: Performance and mechanisms.}, journal = {Journal of hazardous materials}, volume = {404}, number = {Pt B}, pages = {124198}, doi = {10.1016/j.jhazmat.2020.124198}, pmid = {33068987}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Microbial/genetics ; Genes, Bacterial ; Sulfadiazine ; *Sulfonamides ; *Wastewater ; }, abstract = {Sulfonamides, such as sulfadiazine (SDZ), are frequently detected in water and wastewater with their toxic and persistent nature arousing much concern. In this work, a novel electrochemical membrane biofilm reactor (EMBfR) was constructed for the removal of SDZ whilst suppressing the development of antibiotic resistance genes (ARGs). Results showed that the EMBfR achieved 94.9% removal of SDZ, significantly higher than that of a control membrane biofilm reactor (MBfR) without electric field applied (44.3%) or an electrolytic reactor without biofilm (77.3%). Moreover, the relative abundance of ARGs in the EMBfR was only 32.0% of that in MBfR, suggesting that the production of ARGs was significantly suppressed in the EMBfR. The underlying mechanisms relate to (i) the change of the microbial community structure in the presence of the electric field, leading to the enrichment of potential aromatic-degrading microorganisms (e.g., Rhodococcus accounting for 51.0% of the total in the EMBfR compared to 10.0% in the MBfR) and (ii) the unique degradation pathway of SDZ in the EMBfR attributed to the synergistic effect between the electrochemical and biological processes. Our study highlights the benefits of EMBfR in removing pharmaceuticals from contaminated waters and suppressing the development (and transfer) of ARGs in the environment.}, } @article {pmid33068819, year = {2020}, author = {Etemadi, A and Eftekhari Bayati, S and Pourhajibagher, M and Chiniforush, N}, title = {In vitro effect of antimicrobial photodynamic therapy with phycocyanin on Aggregatibacter actinomycetemcomitans biofilm on SLA titanium discs.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {32}, number = {}, pages = {102062}, doi = {10.1016/j.pdpdt.2020.102062}, pmid = {33068819}, issn = {1873-1597}, mesh = {Aggregatibacter actinomycetemcomitans ; *Anti-Infective Agents ; Biofilms ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Phycocyanin/pharmacology ; Titanium ; }, abstract = {BACKGROUND AND PURPOSE: The aim of this in vitro study was to evaluate antimicrobial photodynamic therapy (aPDT) with phycocyanin on Aggregatibacter actinomycetemcomitans biofilm formed on sandblasted, large-grit, and acid-etched (SLA) titanium discs.

MATERIALS AND METHODS: In this in vitro experimental study, the minimum inhibitory concentration (MIC), sublethal dose of diode laser irradiation time, and sublethal dose of aPDT were first determined. Next, 30 SLA titanium discs with 8 mm diameter and 2 mm thickness were incubated with A. actinomycetemcomitans in order for the bacterial biofilm to form, and were randomly divided into 5 groups (n = 6): (I) negative control with no treatment, (II) positive control, immersed in 0.2 % chlorhexidine (CHX) for 5 min, (III) phycocyanin alone with ×2 MIC concentration for 5 min, (IV) diode laser alone (635 nm wavelength, 220 mW power), and (V) PDT with diode laser and phycocyanin. The samples were then sonicated, and the number of colony-forming units (CFUs) on each disc was calculated. Data were analyzed using one-way ANOVA, t-test, and a post-hoc test.

RESULTS: aPDT with 125 μg/mL phycocyanin and 4 min irradiation of 635 nm diode laser decreasedA. actinomycetemcomitans biofilm by 40.07 %. The lowest mean colony count (CFUs/mL) was noted in 0.2 % CHX group (0.0 × 10[5] CFU/mL) while the highest mean was observed in the negative control group (4.55 ± 0.08 × 10[5] CFUs/mL). Using phycocyanin alone significantly decreased the A. actinomycetemcomitans count by 27.54 % (3.29 ± 0.06 × 10[5] CFUs/mL) compared with the negative control group (P < 0.0001). Significant differences were noted between the negative control and other groups (P < 0.0001).

CONCLUSION: aPDT with phycocyanin and diode laser can decrease the A. actinomycetemcomitans biofilm on SLA titanium implant surfaces and can be used as a safe and non-invasive decontamination method for reduction of A. actinomycetemcomitans biofilm on implant surfaces.}, } @article {pmid33066341, year = {2020}, author = {Zhang, H and Yuan, X and Wang, H and Ma, S and Ji, B}, title = {Performance and Microbial Community of Different Biofilm Membrane Bioreactors Treating Antibiotic-Containing Synthetic Mariculture Wastewater.}, journal = {Membranes}, volume = {10}, number = {10}, pages = {}, pmid = {33066341}, issn = {2077-0375}, support = {LGF20E080003, LQ20E080002//Natural Science Foundation of Zhejiang Province/ ; 21808200//National Natural Science Foundation of China/ ; 2017C510006, 2018A61028//Natural Science Foundation of Ningbo/ ; }, abstract = {The performance of pollutant removals, tetracycline (TC) and norfloxacin (NOR) removals, membrane fouling mitigation and the microbial community of three Anoxic/Oxic membrane bioreactors (AO-MBRs), including a moving bed biofilm MBR (MBRa), a fixed biofilm MBR (MBRb) and an AO-MBR (MBRc) for control, were compared in treating antibiotic-containing synthetic mariculture wastewater. The results showed that MBRb had the best effect on antibiotic removal and membrane fouling mitigation compared to the other two bioreactors. The maximum removal rate of TC reached 91.65% and the maximum removal rate of NOR reached 45.46% in MBRb. The addition of antibiotics had little effect on the removal of chemical oxygen demand (COD) and ammonia nitrogen (NH4[+]-N)-both maintained more than 90% removal rate during the entire operation. High-throughput sequencing demonstrated that TC and NOR resulted in a significant decrease in the microbial diversity and the microbial richness MBRs. Flavobacteriia, Firmicutes and Azoarcus, regarded as drug-resistant bacteria, might play a crucial part in the removal of antibiotics. In addition, the dynamics of microbial community had a great change, which included the accumulation of resistant microorganisms and the gradual reduction or disappearance of other microorganisms under antibiotic pressure. The research provides an insight into the antibiotic-containing mariculture wastewater treatment and has certain reference value.}, } @article {pmid33066191, year = {2020}, author = {Gaston, JR and Andersen, MJ and Johnson, AO and Bair, KL and Sullivan, CM and Guterman, LB and White, AN and Brauer, AL and Learman, BS and Flores-Mireles, AL and Armbruster, CE}, title = {Enterococcus faecalis Polymicrobial Interactions Facilitate Biofilm Formation, Antibiotic Recalcitrance, and Persistent Colonization of the Catheterized Urinary Tract.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {33066191}, issn = {2076-0817}, support = {R00 DK105205/DK/NIDDK NIH HHS/United States ; R01 DK123158/DK/NIDDK NIH HHS/United States ; T35 AI089693/AI/NIAID NIH HHS/United States ; UL1 TR001412/TR/NCATS NIH HHS/United States ; }, abstract = {Indwelling urinary catheters are common in health care settings and can lead to catheter-associated urinary tract infection (CAUTI). Long-term catheterization causes polymicrobial colonization of the catheter and urine, for which the clinical significance is poorly understood. Through prospective assessment of catheter urine colonization, we identified Enterococcus faecalis and Proteus mirabilis as the most prevalent and persistent co-colonizers. Clinical isolates of both species successfully co-colonized in a murine model of CAUTI, and they were observed to co-localize on catheter biofilms during infection. We further demonstrate that P. mirabilis preferentially adheres to E. faecalis during biofilm formation, and that contact-dependent interactions between E. faecalis and P. mirabilis facilitate establishment of a robust biofilm architecture that enhances antimicrobial resistance for both species. E. faecalis may therefore act as a pioneer species on urinary catheters, establishing an ideal surface for persistent colonization by more traditional pathogens such as P. mirabilis.}, } @article {pmid33065413, year = {2021}, author = {Kerdi, S and Qamar, A and Vrouwenvelder, JS and Ghaffour, N}, title = {Effect of localized hydrodynamics on biofilm attachment and growth in a cross-flow filtration channel.}, journal = {Water research}, volume = {188}, number = {}, pages = {116502}, doi = {10.1016/j.watres.2020.116502}, pmid = {33065413}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Filtration ; Hydrodynamics ; Membranes, Artificial ; *Water Purification ; }, abstract = {Biofilm attachment and growth in membrane filtration systems are considerably influenced by the localized flow inside the feed channel. The present work aims to map the biofilm attachment/growth mechanism under varying flow conditions. Effect of varying clearance region (space between the spacer filament and membrane surface) on biofouling pattern is investigated by using three 3D-printed pillar spacers having different filament diameters of 340, 500, and 1000 µm while maintaining the same pillar orientation, diameter and height. Direct Numerical Simulations (DNS) and Optical Coherence Tomography (OCT) were carried out to accurately predict the local hydrodynamics behavior and in-situ monitor the biofilm formation. On spacer filaments, biofouling attachment is primarily observed in the regions where low and non-fluctuating shear stresses are present. Conversely, on membrane surface, highest biofouling attachment was observed under spacer filaments where high shear stresses are prevalent along with low clearance height. Furthermore, as filtration time progresses, the biofilm grows faster on the membrane in the center of spacer cells where low shear stress with steady hydrodynamics conditions are prevalent. The proposed hydrodynamics approach envisages a full spectrum of spacer design constraints that can lead to intrinsic biofilm mitigation while improving filtration performance of membranes based water treatment.}, } @article {pmid33063478, year = {2020}, author = {Park, OJ and Jung, S and Park, T and Kim, AR and Lee, D and Jung Ji, H and Seong Seo, H and Yun, CH and Hyun Han, S}, title = {Enhanced biofilm formation of Streptococcus gordonii with lipoprotein deficiency.}, journal = {Molecular oral microbiology}, volume = {35}, number = {6}, pages = {271-278}, doi = {10.1111/omi.12319}, pmid = {33063478}, issn = {2041-1014}, mesh = {*Bacterial Proteins/genetics ; *Biofilms ; Dentin/microbiology ; Humans ; In Vitro Techniques ; Lipoproteins/*genetics ; Quorum Sensing ; *Streptococcus gordonii/genetics/physiology ; }, abstract = {Streptococcus gordonii is a commensal Gram-positive bacterium that acts as an opportunistic pathogen that can cause apical periodontitis, endocarditis, and pneumonia. Biofilm formation of bacteria is important for the initiation and progression of such diseases. Although lipoproteins play key roles in physiological functions, the role of lipoproteins of S. gordonii in its biofilm formation has not been clearly understood. In this study, we investigated the role of lipoproteins of S. gordonii in the bacterial biofilm formation using its lipoprotein-deficient strain (Δlgt). The S. gordonii Δlgt exhibited increased biofilm formation on the human dentin slices or on the polystyrene surfaces compared to the wild-type strain, while its growth rate did not differ from that of the wild-type. In addition, the S. gordonii Δlgt strain exhibited the enhanced LuxS mRNA expression and AI-2 production, which is known to be a positive regulator of biofilm formation, compared to the wild-type. Concordantly, the augmented biofilm formation of S. gordonii Δlgt was attenuated by an AI-2 inhibitor, D-ribose. In addition, lipoproteins from purified S. gordonii inhibited the biofilm formation of S. gordonii wild-type and Δlgt. Taken together, these results suggest that lipoprotein-deficient S. gordonii form biofilms more effectively than the wild-type strain, which might be related to the AI-2 quorum-sensing system.}, } @article {pmid33062684, year = {2020}, author = {Kaneko, T and Saito, T and Shobuike, T and Miyamoto, H and Matsuda, J and Fukazawa, K and Ishihara, K and Tanaka, S and Moro, T}, title = {2-Methacryloyloxyethyl Phosphorylcholine Polymer Coating Inhibits Bacterial Adhesion and Biofilm Formation on a Suture: An In Vitro and In Vivo Study.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {5639651}, pmid = {33062684}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/pharmacology ; Male ; Methacrylates/chemistry/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Mice ; Mice, Inbred C57BL ; Phosphorylcholine/*analogs & derivatives/chemistry/pharmacology ; Staphylococcus aureus/drug effects ; Sutures/*microbiology ; }, abstract = {Initial bacterial adhesion to medical devices and subsequent biofilm formation are known as the leading causes of surgical site infection (SSI). Therefore, inhibition of bacterial adhesion and biofilm formation on the surface of medical devices can reduce the risk of SSIs. In this study, a highly hydrophilic, antibiofouling surface was prepared by coating the bioabsorbable suture surface with poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate) (PMB). The PMB-coated and noncoated sutures exhibited similar mechanical strength and surface morphology. The effectiveness of the PMB coating on the suture to suppress adhesion and biofilm formation of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus was investigated both in vitro and in vivo. The bacterial adhesion test revealed that PMB coating significantly reduced the number of adherent bacteria, with no difference in the number of planktonic bacteria. Moreover, fluorescence microscopy and scanning electron microscopy observations of adherent bacteria on the suture surface after contact with bacterial suspension confirmed PMB coating-mediated inhibition of biofilm formation. Additionally, we found that the PMB-coated sutures exhibited significant antibiofouling effects in vivo. In conclusion, PMB-coated sutures demonstrated bacteriostatic effects associated with a highly hydrophilic, antibiofouling surface and inhibited bacterial adhesion and biofilm formation. Therefore, PMB-coated sutures could be a new alternative to reduce the risk of SSIs.}, } @article {pmid33059484, year = {2020}, author = {Prajapati, A and Chanda, MM and Dhayalan, A and Yogisharadhya, R and Chaudhary, JK and Mohanty, NN and Shivachandra, SB}, title = {Variability in in vitro biofilm production and antimicrobial sensitivity pattern among Pasteurella multocida strains.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {938-950}, doi = {10.1080/08927014.2020.1833192}, pmid = {33059484}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents ; *Biofilms ; Microbial Sensitivity Tests ; *Pasteurella multocida ; }, abstract = {Biofilm production, hitherto an uncharacterized feature among circulating Pasteurella multocida strains, was studied along with the antibiotic susceptibility pattern. On the basis of biofilm formation ability, all the strains were categorized into four groups under six different culture conditions: strong biofilm-forming (22%), moderate (19%), weak (51%), and non-adherent (7%). Strains from serogroups A and B formed significant biofilms in at least one culture condition whereas strains from serogroup D were unable to form biofilms. All strains were found to be susceptible to tetracycline. In addition, the correlation between diverse factors (host, capsule type, clinical condition and the tadD gene) as well as antimicrobial susceptibility in biofilm production were analyzed by Joint distribution models, and showed that enrofloxacin and azithromycin resistant strains were positively correlated with strong biofilm production.}, } @article {pmid33059473, year = {2020}, author = {Brilhante, RSN and Pereira, VS and Nobre, AFD and Oliveira, JS and Fernandes, MR and Costa, ADC and Rodrigues, AM and Camargo, ZP and Pereira-Neto, WA and Sidrim, JJC and Rocha, MFG}, title = {Exogenous fungal quorum sensing molecules inhibit planktonic cell growth and modulate filamentation and biofilm formation in the Sporothrix schenckii complex.}, journal = {Biofouling}, volume = {36}, number = {8}, pages = {909-921}, doi = {10.1080/08927014.2020.1828373}, pmid = {33059473}, issn = {1029-2454}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; Farnesol/pharmacology ; Plankton ; *Quorum Sensing ; *Sporothrix ; }, abstract = {This study investigated the effect of the quorum sensing molecules (QSMs) farnesol, 2-phenylehtanol, tyrosol and tryptophol against planktonic cells, filamentation and biofilms of Sporothrix spp. The antifungal activity of QSMs was evaluated by broth microdilution. QSMs showed MICs in the ranges of 0.01-1 µM (farnesol), 1-8 mM (2-phenylehtanol and tyrosol), and >16 mM (tryptophol). Filamentous biofilm formation was inhibited by farnesol and 2-phenylehtanol and stimulated by tyrosol. Yeast biofilm formation was inhibited by 2-phenylehtanol and tyrosol. Tryptophol did not affect Sporothrix biofilm formation. QSMs showed MICs against mature biofilms of 8-32 µM (farnesol), 8-32 mM (2-phenylehtanol) and 64-128 mM (tyrosol). In conclusion, farnesol, 2-phenylethanol and tyrosol have antifungal activity against planktonic and sessile cells and modulate filamentation and biofilm formation in Sporothrix spp.}, } @article {pmid33059384, year = {2021}, author = {Todhanakasem, T and Triwattana, K and Pom, J and Havanapan, P and Koombhongse, P and Thitisak, P}, title = {Physiological studies of the Pediococcus pentosaceus biofilm.}, journal = {Letters in applied microbiology}, volume = {72}, number = {2}, pages = {178-186}, doi = {10.1111/lam.13351}, pmid = {33059384}, issn = {1472-765X}, support = {F-CO-ITAP-07//Innovation Technology Assistance Program (ITAP)/ ; }, mesh = {Animals ; Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Glyceraldehyde-3-Phosphate Dehydrogenases/*metabolism ; Humans ; Pediococcus pentosaceus/*growth & development/*physiology ; Plankton/microbiology ; Polyesters/metabolism ; Probiotics ; Proteomics ; Signal Transduction ; Soybeans/metabolism ; }, abstract = {Pediococcus pentosaceus, a bacterium recently used in human and animal probiotics, was used in combination with supports made from polylactic acid composite soybean meal was used to study biofilm formation, and it was found that dense biofilms developed by Day 1. Proteomic comparison between planktonic and biofilm cultures of P. pentosaceus showed distinct expression patterns of intracellular and extracellular proteins. Type I glyceraldehyde-3-phosphate dehydrogenase was upregulated in biofilm cultures and mediated cell adhesion and encouraged biofilm production. GMP synthase, which regulates GMP synthesis and acts as an intracellular signal molecule to control cell mechanisms and has been exploited in the development of new therapeutic agents, was also upregulated in the biofilm mode of growth. The present work serves as a basis for future studies examining the complex network of systems that regulate lactic acid bacterial (LAB) biofilm formation and can serve as a framework for studies of production of therapeutic agents from LAB.}, } @article {pmid33059364, year = {2020}, author = {Miryala, S and Nair, VG and Chandramohan, S and Srinandan, CS}, title = {Matrix inhibition by Salmonella excludes uropathogenic E. coli from biofilm.}, journal = {FEMS microbiology ecology}, volume = {97}, number = {1}, pages = {}, doi = {10.1093/femsec/fiaa214}, pmid = {33059364}, issn = {1574-6941}, mesh = {Biofilms ; *Escherichia coli Infections ; *Escherichia coli Proteins ; Humans ; Salmonella/genetics ; *Uropathogenic Escherichia coli/genetics ; }, abstract = {Biofilm is a predominant lifestyle of bacteria that comprises of cells as collectives enmeshed in a polymeric matrix. Biofilm formation is vital for bacterial species as it provides access to nutrients and protects the cells from environmental stresses. Here we show that interference in biofilm matrix production is a strategy by the competing bacterial species to reduce the ability of the other species to colonize a surface. Escherichia coli colonies that differ in matrix production display different morphologies on Congo red agar media, which we exploited for screening bacterial isolates capable of inhibiting the matrix. The cell-free supernatants from growth culture of the screened isolates impaired uropathogenic E. coli (UPEC) UTI89 strain's biofilm. A physicochemical analysis suggested that the compound could be a glycopeptide or a polysaccharide. Isolates that inhibited matrix production belonged to species of the family Enterobacteriaceae such as Shigella, Escherichia, Enterobacter and Salmonella. Competition experiments between the isolates and the UPEC strain resulted in mutual inhibition, particularly during biofilm formation causing significant reduction in productivity and fitness. Furthermore, we show that Salmonella strains competitively excluded the UPEC strain in the biofilm by inhibiting its matrix production, highlighting the role of interference competition.}, } @article {pmid33059291, year = {2021}, author = {He, L and Yang, Q and Zhong, Y and Yao, F and Wu, B and Hou, K and Pi, Z and Wang, D and Li, X}, title = {Electro-assisted autohydrogenotrophic reduction of perchlorate and microbial community in a dual-chamber biofilm-electrode reactor.}, journal = {Chemosphere}, volume = {264}, number = {Pt 2}, pages = {128548}, doi = {10.1016/j.chemosphere.2020.128548}, pmid = {33059291}, issn = {1879-1298}, mesh = {Bacteria/genetics ; Biofilms ; Bioreactors ; Electrodes ; *Microbiota ; Nitrates ; Oxidation-Reduction ; *Perchlorates ; }, abstract = {The electro-assisted autohydrogenotrophic reduction of perchlorate (ClO4[-]) was investigated in a dual-chamber biofilm-electrode reactor (BER), in which the microbial community was inoculated from natural sediments. To avoid the effect of extreme pH and direct electron transfer on perchlorate reduction, a novel cathode configuration was designed. The pH of the cathode compartment was successfully controlled in the range of 7.2-8.4 during whole experiment. The effective biological autohydrogenotrophic reduction of perchlorate was achieved using hydrogen generated in-situ on the electrode surface, and the removal rate of 10 mg L[-1] perchlorate reached 98.16% at HRT of 48 h. The highest perchlorate removal flux reached to 1498.420 mg m[-2]·d[-1] with a 0.410 kW·h g-perchlorate[-1] energy consumption. The microbial community evolution in the BER was determined by high-throughput sequencing and the results indicated that the Firmicutes and Bacteroidetes were dominant at phylum level when perchlorate concentration was 10 mg L[-1] or lower. And the Proteobacteria became ascendant at the perchlorate concentration of 20 mg L[-1]. The functional populations for perchlorate reduction were successfully enriched including Nitrosomonas (30%), Thermomonas (9%), Comamonas (8%) and Hydrogenophaga (3%). Meanwhile, the proportion of functional population in biofilm linked to perchlorate concentration. With the increase of influent perchlorate concentration, the perchlorate-reducing bacteria (PRB) were enriched successfully and became ascendant.}, } @article {pmid33057751, year = {2020}, author = {Radovanovic, RS and Savic, NR and Ranin, L and Smitran, A and Opavski, NV and Tepavcevic, AM and Ranin, J and Gajic, I}, title = {Biofilm Production and Antimicrobial Resistance of Clinical and Food Isolates of Pseudomonas spp.}, journal = {Current microbiology}, volume = {77}, number = {12}, pages = {4045-4052}, doi = {10.1007/s00284-020-02236-4}, pmid = {33057751}, issn = {1432-0991}, support = {175039//Ministry of Education, Science and Technological Development of the Republic of Serbia/ ; No II 46009//Ministry of Education, Science and Technological Development of the Republic of Serbia/ ; }, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; *Drug Resistance, Bacterial ; Food Microbiology ; Humans ; Microbial Sensitivity Tests ; Pseudomonas/*drug effects/genetics ; *Pseudomonas Infections ; Pseudomonas aeruginosa/drug effects/genetics ; beta-Lactamases ; }, abstract = {Due to its ubiquity, ability to form biofilms, and acquire resistance mechanisms, Pseudomonas spp. become one of the major challenge for healthcare settings and food industry. The aims of this study were to assess the biofilm production of Pseudomonas spp. recovered from clinical and food specimens and to evaluate their antimicrobial resistance. A total of 108 isolates of Pseudomonas spp. were included in the study, 48 being clinical isolates recovered from patients admitted to four tertiary care hospitals throughout Serbia and 60 were isolated from the bulk tank milk samples and meat carcasses. Biofilm production was analyzed by microtiter plate assay. Antimicrobial susceptibility was evaluated by disk diffusion method according to the CLSI guidelines, while class A and B β-lactamases encoding genes were screened by PCR. A total of 98 (90.7%) strains were biofilm producers (moderate producer: 68, 69.4%; strong producer: 8, 8.2%). Although a slightly higher percentage of clinical isolates were biofilm producers (91.7%) compared to food isolates (90%), statistical significance was not observed (P > 0.05). The proportion of carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates was significantly higher among clinical (42%) isolates compared to food (1.7%) Pseudomonads (P < 0.05). The blaPER and blaNDM genes were found in ESBL (seven isolates) and MBL (two isolates) production, respectively. In the present study, we confirmed that biofilm formation was highly present in both clinical and food Pseudomonas spp. irrespective of the prior existence of resistance genes. Additionally, clinical settings pose a major reservoir of MDR Pseudomonas spp. and especially CRPA isolates.}, } @article {pmid33057038, year = {2020}, author = {Monti, D and Hubas, C and Lourenço, X and Begarin, F and Haouisée, A and Romana, L and Lefrançois, E and Jestin, A and Budzinski, H and Tapie, N and Risser, T and Mansot, JL and Keith, P and Gros, O and Lopez, PJ and Lauga, B}, title = {Physical properties of epilithic river biofilm as a new lead to perform pollution bioassessments in overseas territories.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {17309}, pmid = {33057038}, issn = {2045-2322}, abstract = {Chlordecone (CLD) levels measured in the rivers of the French West Indies were among the highest values detected worldwide in freshwater ecosystems, and its contamination is recognised as a severe health, environmental, agricultural, economic, and social issue. In these tropical volcanic islands, rivers show strong originalities as simplified food webs, or numerous amphidromous migrating species, making the bioindication of contaminations a difficult issue. The objective of this study was to search for biological responses to CLD pollution in a spatially fixed and long-lasting component of the rivers in the West Indies: the epilithic biofilm. Physical properties were investigated through complementary analyses: friction, viscosity as well as surface adhesion were analyzed and coupled with measures of biofilm carbon content and exopolymeric substance (EPS) production. Our results have pointed out a mesoscale chemical and physical reactivity of the biofilm that can be correlated with CLD contamination. We were able to demonstrate that epilithic biofilm physical properties can effectively be used to infer freshwater environmental quality of French Antilles rivers. The friction coefficient is reactive to contamination and well correlated to carbon content and EPS production. Monitoring biofilm physical properties could offer many advantages to potential users in terms of effectiveness and ease of use, rather than more complex or time-consuming analyses.}, } @article {pmid33056998, year = {2020}, author = {Izadi, P and Fontmorin, JM and Godain, A and Yu, EH and Head, IM}, title = {Parameters influencing the development of highly conductive and efficient biofilm during microbial electrosynthesis: the importance of applied potential and inorganic carbon source.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {40}, pmid = {33056998}, issn = {2055-5008}, mesh = {Acetates/chemistry ; Acetobacterium/genetics/*physiology ; Bacterial Proteins/genetics ; Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Carbon Dioxide/*chemistry ; Electric Conductivity ; Electrodes ; Oxidoreductases/genetics ; Silver Compounds/chemistry ; }, abstract = {Cathode-driven applications of bio-electrochemical systems (BESs) have the potential to transform CO2 into value-added chemicals using microorganisms. However, their commercialisation is limited as biocathodes in BESs are characterised by slow start-up and low efficiency. Understanding biosynthesis pathways, electron transfer mechanisms and the effect of operational variables on microbial electrosynthesis (MES) is of fundamental importance to advance these applications of a system that has the capacity to convert CO2 to organics and is potentially sustainable. In this work, we demonstrate that cathodic potential and inorganic carbon source are keys for the development of a dense and conductive biofilm that ensures high efficiency in the overall system. Applying the cathodic potential of -1.0 V vs. Ag/AgCl and providing only gaseous CO2 in our system, a dense biofilm dominated by Acetobacterium (ca. 50% of biofilm) was formed. The superior biofilm density was significantly correlated with a higher production yield of organic chemicals, particularly acetate. Together, a significant decrease in the H2 evolution overpotential (by 200 mV) and abundant nifH genes within the biofilm were observed. This can only be mechanistically explained if intracellular hydrogen production with direct electron uptake from the cathode via nitrogenase within bacterial cells is occurring in addition to the commonly observed extracellular H2 production. Indeed, the enzymatic activity within the biofilm accelerated the electron transfer. This was evidenced by an increase in the coulombic efficiency (ca. 69%) and a 10-fold decrease in the charge transfer resistance. This is the first report of such a significant decrease in the charge resistance via the development of a highly conductive biofilm during MES. The results highlight the fundamental importance of maintaining a highly active autotrophic Acetobacterium population through feeding CO2 in gaseous form, which its dominance in the biocathode leads to a higher efficiency of the system.}, } @article {pmid33055348, year = {2020}, author = {Stetsyk, MO and Stetsyk, AO and Zhero, NI and Kostenko, EY and Kostenko, SB and Pirchak, ID}, title = {MODERN SUBMISSION OF FORMATION, COMPOSITION AND ROLE OF ORAL (DENTAL) BIOFILM IN DEVELOPMENT OF PERIODONTAL DISEASES.}, journal = {Wiadomosci lekarskie (Warsaw, Poland : 1960)}, volume = {73}, number = {8}, pages = {1761-1764}, pmid = {33055348}, issn = {0043-5147}, mesh = {Biofilms ; Humans ; *Periodontal Diseases ; Periodontium ; }, abstract = {OBJECTIVE: The aim: To investigate current trends in the study of oral biofilm and its control.

PATIENTS AND METHODS: Materials and methods: A research of 32 literature sources has been made and it has been taken into account that some terminological differences in determining objects of study.

CONCLUSION: Conclusions: Detailed analysis of modern domestic and foreign literature argues the necessity of further in-depth study of oral biofilms. Understanding the ethiological factors and mechanisms of the pathogenesis periodontal tissues inflammatory diseases gives the opportunity to treat targetly by destroying complicated sections of the vital activities and oral biofilm microorganisms relationships.}, } @article {pmid33052843, year = {2020}, author = {Khoddami, S and Chew, BH and Lange, D}, title = {Problems and solutions of stent biofilm and encrustations: A review of literature.}, journal = {Turkish journal of urology}, volume = {46}, number = {Supp. 1}, pages = {S11-S18}, pmid = {33052843}, issn = {2149-3235}, abstract = {A ureteral stent is a commonly implanted urological device in patients with urinary tract obstruction. The main role of these stents is to allow adequate drainage of urine from the kidney into the bladder. Individuals with strictures, tumors, or obstructions from urinary stones do not have adequate urine flow and require ureteral stents as a part of their treatment to avoid potential hydronephrosis and renal failure. Although ureteral stents are highly effective in treating urinary tract obstructions, they have associated morbidities, such as biofilm formation and encrustation. Researchers have studied about how to diminish these negative outcomes by developing novel stent materials. Different coatings and biomaterials have been developed to reduce bacterial adhesion and crystal deposition onto the stent surfaces. Moreover, new investigation technologies, such as microfluidic platforms and encrustation sensors, have been utilized to better study the stents. Biofilms and encrustations can stem from bacterial origins; therefore, understanding the urinary microbiome will also provide insight into the solutions for treating them. There are still some gaps in our knowledge regarding the exact underlying mechanisms of stent-associated biofilms and encrustation. Future studies should include continuous testing of novel stent biomaterials for safety and efficacy, developing new technologies for identifying and extracting biofilms, enriching the assessment of stent encrustation, and diving deeper into understanding the urinary microbiome.}, } @article {pmid33050521, year = {2020}, author = {Talapko, J and Škrlec, I}, title = {The Principles, Mechanisms, and Benefits of Unconventional Agents in the Treatment of Biofilm Infection.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {13}, number = {10}, pages = {}, pmid = {33050521}, issn = {1424-8247}, abstract = {Today, researchers are looking at new ways to treat severe infections caused by resistance to standard antibiotic therapy. This is quite challenging due to the complex and interdependent relationships involved: the cause of infection-the patient-antimicrobial agents. The sessile biofilm form is essential in research to reduce resistance to very severe infections (such as ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter spp). The purpose of this study is to elucidate the mechanisms of the occurrence, maintenance, and suppression of biofilm infections. One form of biofilm suppression is the efficient action of natural antagonists of bacteria-bacteriophages. Bacteriophages effectively penetrate the biofilm's causative cells. They infect those bacterial cells and either destroy them or prevent the infection spreading. In this process, bacteriophages are specific, relatively easy to apply, and harmless to the patient. Antimicrobial peptides (AMPs) support the mechanisms of bacteriophages' action. AMPs could also attack and destroy infectious agents on their own (even on biofilm). AMPs are simple, universal peptide molecules, mainly cationic peptides. Additional AMP research could help develop even more effective treatments of biofilm (bacteriophages, antibiotics, AMPs, nanoparticles). Here, we review recent unconventional agents, such as bacteriophages and AMPs, used for eradication of biofilm, providing an overview of potentially new biofilm treatment strategies.}, } @article {pmid33050176, year = {2020}, author = {Fuchs, AL and Miller, IR and Schiller, SM and Ammons, MCB and Eilers, B and Tripet, B and Copié, V}, title = {Pseudomonas aeruginosa Planktonic- and Biofilm-Conditioned Media Elicit Discrete Metabolic Responses in Human Macrophages.}, journal = {Cells}, volume = {9}, number = {10}, pages = {}, pmid = {33050176}, issn = {2073-4409}, support = {P20 GM103408/GM/NIGMS NIH HHS/United States ; S10 RR026659/RR/NCRR NIH HHS/United States ; P20 GM103474/GM/NIGMS NIH HHS/United States ; K01 GM103821/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; Cells, Cultured ; Culture Media, Conditioned/metabolism/*pharmacology ; Cytokines/metabolism ; Humans ; Macrophages/*drug effects/*metabolism ; Metabolomics/methods ; Plankton/metabolism ; Pseudomonas aeruginosa/metabolism/pathogenicity ; }, abstract = {Macrophages (MΦs) are prevalent innate immune cells, present throughout human bodily tissues where they orchestrate innate and adaptive immune responses to maintain cellular homeostasis. MΦs have the capacity to display a wide array of functional phenotypes due to different microenvironmental cues, particularly soluble bacterial secretory products. Recent evidence has emerged demonstrating that metabolism supports MΦ function and plasticity, in addition to energy and biomolecular precursor production. In this study, 1D [1]H-NMR-based metabolomics was used to identify the metabolic pathways that are differentially altered following primary human monocyte-derived MΦ exposure to P. aeruginosa planktonic- and biofilm-conditioned media (PCM and BCM). Metabolic profiling of PCM- and BCM-exposed MΦs indicated a significant increase in glycolytic metabolism, purine biosynthesis, and inositol phosphate metabolism. In addition, these metabolic patterns suggested that BCM-exposed MΦs exhibit a hyperinflammatory metabolic profile with reduced glycerol metabolism and elevated catabolism of lactate and amino acids, relative to PCM-exposed MΦs. Altogether, our study reveals novel findings concerning the metabolic modulation of human MΦs after exposure to secretory microbial products and contributes additional knowledge to the field of immunometabolism in MΦs.}, } @article {pmid33049660, year = {2021}, author = {Nie, L and Chang, P and Ji, C and Zhang, F and Zhou, Q and Sun, M and Sun, Y and Politis, C and Shavandi, A}, title = {Poly(acrylic acid) capped iron oxide nanoparticles via ligand exchange with antibacterial properties for biofilm applications.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {197}, number = {}, pages = {111385}, doi = {10.1016/j.colsurfb.2020.111385}, pmid = {33049660}, issn = {1873-4367}, mesh = {Acrylic Resins ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; Ligands ; Magnetic Iron Oxide Nanoparticles ; *Metal Nanoparticles ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus ; *Staphylococcus aureus ; X-Ray Diffraction ; }, abstract = {Biofilm infections pose a rising threat to public health due to its existing protective shield, which preventing biocide penetration. Here, the oleate-capped iron oxide nanoparticles (OIONPs) were synthesized by the high-temperature method first; after then, the poly(acrylic acid)-capped iron oxide nanoparticles (PIONPs) were obtained via a ligand exchange reaction between OIONPs and sodium poly(acrylic acid). The physicochemical properties of PIONPs were evaluated by Fourier-transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Transmission Electron Microscopy (STEM), Dynamic Light Scattering (DLS), and zeta potential. The FT-IR analysis confirmed the successful ligand exchange on the surface of iron oxide nanoparticles. STEM images displayed that the prepared PIONPs were monodisperse spherical nanoparticles. The PIONPs were stable in ultrapure water and could be kept for 5 weeks without aggregation. Next, Cell Counting Kit-8 (CCK-8) assay and fluorescent images confirmed the excellent cytocompatibility of PIONPs, while the iron concentration of PIONPs was in the range of 5∼120 mg/L. Finally, PIONPs exhibited efficient antibacterial activity against E. coli and S. aureus, and Staphylococcus aureus subsp. aureus Rosenbach (SASAR) biofilm could be destroyed by treating PIONPs under alternating current (AC) applied field conditions.}, } @article {pmid33049327, year = {2021}, author = {Nunes, SO and Rosa, HDS and Canellas, ALB and Romanos, MTV and Dos Santos, KRN and Muricy, G and Oelemann, WMR and Laport, MS}, title = {High reduction of staphylococcal biofilm by aqueous extract from marine sponge-isolated Enterobacter sp.}, journal = {Research in microbiology}, volume = {172}, number = {1}, pages = {103787}, doi = {10.1016/j.resmic.2020.10.002}, pmid = {33049327}, issn = {1769-7123}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Catheter-Related Infections/drug therapy/microbiology ; Catheters, Indwelling/microbiology ; Cell Extracts/*pharmacology ; Cell Line ; Cross Infection/drug therapy/microbiology ; Enterobacter/*metabolism ; L Cells ; Mice ; Microbial Sensitivity Tests ; Porifera/microbiology ; Staphylococcal Infections/drug therapy/microbiology/prevention & control ; Staphylococcus aureus/*drug effects ; Staphylococcus epidermidis/*drug effects ; }, abstract = {Staphylococcus aureus and Staphylococcus epidermidis are among the most important bacterial species responsible for biofilm formation on indwelling medical devices, including orthopaedic implants. The increasing resistance to antimicrobials, partly attributed to the ability to form biofilms, is a challenge for the development of new antimicrobial agents. In this study, the cell-free supernatant obtained from sponge-associated Enterobacter strain 84.3 culture inhibited biofilm formation (>65%) and dissociated mature biofilm (>85%) formed by S. aureus and S. epidermidis strains. The culture supernatant was subjected to solvent partitioning and the aqueous extract presented a concentration-dependent antibiofilm activity for each strain with a minimum biofilm eradication concentration (MBEC) ranging from 16 to 256 μg/mL. The effect of the aqueous extract on mature S. aureus biofilm was analyzed by confocal scanning laser microscopy, showing a significant reduction of the biofilm layer as well as diminished interactions among the cells. This extract is not toxic for mammalian cells (L929 cell line). Studies targeting substances with antibiofilm activity gained significant attention in recent years due to difficult-to-treat biofilm infections. Here, sponge-associated Enterobacter 84.3 proved to be a source of substances capable of eradicating staphylococcal biofilm, with potential medical use in the future.}, } @article {pmid33046677, year = {2021}, author = {Jin, X and Zhou, J and Richey, G and Wang, M and Hong, SMC and Hong, SH}, title = {Undecanoic Acid, Lauric Acid, and N-Tridecanoic Acid Inhibit Escherichia coli Persistence and Biofilm Formation.}, journal = {Journal of microbiology and biotechnology}, volume = {31}, number = {1}, pages = {130-136}, pmid = {33046677}, issn = {1738-8872}, support = {R15 AI130988/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections ; Biofilms/*drug effects/*growth & development ; Drug Tolerance ; Escherichia coli/*drug effects ; Fatty Acids/*pharmacology ; Lauric Acids/*pharmacology ; }, abstract = {Persister cell formation and biofilms of pathogens are extensively involved in the development of chronic infectious diseases. Eradicating persister cells is challenging, owing to their tolerance to conventional antibiotics, which cannot kill cells in a metabolically dormant state. A high frequency of persisters in biofilms makes inactivating biofilm cells more difficult, because the biofilm matrix inhibits antibiotic penetration. Fatty acids may be promising candidates as antipersister or antibiofilm agents, because some fatty acids exhibit antimicrobial effects. We previously reported that fatty acid ethyl esters effectively inhibit Escherichia coli persister formation by regulating an antitoxin. In this study, we screened a fatty acid library consisting of 65 different fatty acid molecules for altered persister formation. We found that undecanoic acid, lauric acid, and N-tridecanoic acid inhibited E. coli BW25113 persister cell formation by 25-, 58-, and 44-fold, respectively. Similarly, these fatty acids repressed persisters of enterohemorrhagic E. coli EDL933. These fatty acids were all medium-chain saturated forms. Furthermore, the fatty acids repressed Enterohemorrhagic E. coli (EHEC) biofilm formation (for example, by 8-fold for lauric acid) without having antimicrobial activity. This study demonstrates that medium-chain saturated fatty acids can serve as antipersister and antibiofilm agents that may be applied to treat bacterial infections.}, } @article {pmid33045545, year = {2021}, author = {Renaudie, M and Dumas, C and Vuilleumier, S and Ernst, B}, title = {Biohydrogen production in a continuous liquid/gas hollow fiber membrane bioreactor: Efficient retention of hydrogen producing bacteria via granule and biofilm formation.}, journal = {Bioresource technology}, volume = {319}, number = {}, pages = {124203}, doi = {10.1016/j.biortech.2020.124203}, pmid = {33045545}, issn = {1873-2976}, mesh = {Bacteria ; Biofilms ; *Bioreactors ; Clostridium ; Fermentation ; *Hydrogen ; }, abstract = {The aim of this work was to develop a continuous liquid/gas membrane bioreactor (L/G MBR), i.e. a fermenting module including hollow fibers membrane for L/G separation, for biohydrogen production by dark fermentation. Originally seeded with sludge from a wastewater treatment plant, the L/G MBR underwent a complete stop for eight months. It was then operated without further reseeding. In the present experiment, performed 551 days after the last reseeding, average hydrogen yield of 1.1 ± 0.2 mol per mol glucose added and hydrogen productivity of 135 ± 22 mL/L/h were reached, with acetate and butyrate as the main metabolite products. DNA sequence analysis revealed that Clostridium beijerinckii, Clostridium pasteurianum and Enterobacter sp. were dominant in liquid outlet, in a biofilm on the surface of the hollow fibers and in microbial granules. The L/G MBR has potential for the concentration and the long-term maintenance of an active hydrogen-producing bacterial community without need for reseeding.}, } @article {pmid33045439, year = {2020}, author = {Kim, S and Jin, JS and Lee, DW and Kim, J}, title = {Antibacterial activities of and biofilm removal by Ablysin, an endogenous lysozyme-like protein originated from Acinetobacter baumannii 1656-2.}, journal = {Journal of global antimicrobial resistance}, volume = {23}, number = {}, pages = {297-302}, doi = {10.1016/j.jgar.2020.09.017}, pmid = {33045439}, issn = {2213-7173}, mesh = {*Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Muramidase/pharmacology ; }, abstract = {OBJECTIVES: Multidrug-resistant (MDR) Acinetobacter baumannii as well as MDR Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and other Enterobacteriaceae ('ESKAPE' pathogens) currently present a major public-health problem. These bacteria are associated with opportunistic infections in intensive care units as well as in immunocompromised patients. There is an urgent need for new alternative antibacterials to control these MDR bacteria. Here we describe the antibacterial action of a novel peptidoglycan hydrolase that targets the bacterial cell wall, identified in the genome of clinical isolate A. baumannii 1656-2.

METHODS: We generated a recombinant protein from a sequence encoding a lysozyme-like protein identified in the genome of A. baumannii 1656-2. We named it Ablysin and tested its antibacterial activity and biofilm removal ability targeting ESKAPE pathogens.

RESULTS: In vitro application of Ablysin resulted in growth inhibition of the six aforementioned bacterial species, with a highest activity against A. baumannii. Electron microscopy revealed the concentration-dependent (250-2000 μg/mL) rupture of A. baumannii bacterial cells accompanied by elimination of the associated biofilm.

CONCLUSIONS: Ablysin represents a potential new class of antibacterial proteins that can be used to target MDR A. baumannii as well as other bacterial species.}, } @article {pmid33044989, year = {2020}, author = {Moreno, A and Dos Santos, DM and Lamartine de Moraes Melo Neto, C and Luiz de Melo Moreno, A and de Magalhães Bertoz, AP and Goiato, MC}, title = {In vitro evaluation of the effect of different disinfectants on the biofilm of Staphylococcus epidermidis and Staphylococcus aureus formed on acrylic ocular prostheses.}, journal = {PloS one}, volume = {15}, number = {10}, pages = {e0240116}, pmid = {33044989}, issn = {1932-6203}, mesh = {Biofilms/*drug effects ; Disinfectants/*pharmacology ; Disinfection/methods ; Eye, Artificial/*microbiology ; Humans ; Staphylococcal Infections/prevention & control ; Staphylococcus aureus/*drug effects/physiology ; Staphylococcus epidermidis/*drug effects/physiology ; }, abstract = {The aim of this study was to evaluate the effect of disinfectants on the biofilm of Staphylococcus aureus and Staphylococcus epidermidis formed on the acrylic surface of ocular prostheses. In this study, 396 acrylic specimens were manufactured (50% for Staphylococcus epidermidis, and 50% for Staphylococcus aureus). For each bacterium, 66 specimens were subjected to biofilm formation on their surfaces for 24 hours, 66 specimens were subjected to biofilm formation on their surfaces for 48 hours, and 66 specimens were subjected to biofilm formation on their surfaces for 72 hours. Then, they were divided into groups according to disinfection method (n = 6): sterile distilled water for 10, 15, 30 min, and 6 hours (control); soap for 30 min (NES30); Opti-Free for 30 min (OPF30) and 6 h (OPF6); Efferdent for 15 min (EFF15); and 0.5%, 2%, and 4% chlorhexidine for 10 min (0.5% CHX10, 2% CHX10, and 4% CHX10). After the treatments, the specimens were vortexed to release the biofilm and the counting of bacterial colonies was performed (CFU/mL). Three-way ANOVA and the Tukey-Kramer HSD test were used (α = 0.05). For Staphylococcus epidermidis, there was no significant difference between NES30, OPF30, and OPF6 with their respective control groups; nor between NES30, OPF30, and OPF6 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, there was no significant difference between NES30 and OPF30 with their control group; nor between NES30 and OPF30 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, OPF6 showed a significant reduction in the number of CFU/mL when compared with its control group, NES30, and OPF30, regardless of the biofilm development period (P <0.05). For both bacteria, 0.5% CHX10, 2% CHX10,4% CHX10, and EFF15 showed a significant reduction in the number of CFU/mL when compared with their control groups, NES30, OPF30, and OPF6, regardless of the biofilm development period (P <0.05). Therefore, EFF15 and CHX (0.5%, 2% and 4%) were effective in reducing Staphylococcus epidermidis and Staphylococcus aureus on acrylic surfaces. NES30 and OPF (30 and 6) are not recommended.}, } @article {pmid33042098, year = {2020}, author = {Wu, R and Tao, Y and Cao, Y and Zhou, Y and Lin, H}, title = {Streptococcus mutans Membrane Vesicles Harboring Glucosyltransferases Augment Candida albicans Biofilm Development.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {581184}, pmid = {33042098}, issn = {1664-302X}, abstract = {Candida albicans, as the most common fungus in the oral cavity, is often detected in early childhood caries. Streptococcus mutans is the major etiological agent of dental caries, but the role of S. mutans on C. albicans growth and biofilm development remains to be elucidated. Membrane vesicles (MVs) are a cell-secreted subcellular fraction that play an important role in intercellular communication and disease progression. In the present study, we investigated whether MVs from S. mutans augment C. albicans growth and biofilm development. The results indicated that S. mutans MVs augmented C. albicans biofilm development but had no significant effect on C. albicans growth under planktonic conditions. Subsequently, we labeled S. mutans MVs with PKH26 and used confocal laser scanning microscopy (CLSM) to track S. mutans MVs, which were observed to be located in the C. albicans biofilm extracellular matrix. Monosaccharide tests showed that S. mutans MVs contribute to sucrose metabolism in C. albicans. Polysaccharides were significantly enriched in the S. mutans MV-treated group. MVs from ΔgtfBC mutant strains were compared with those from the wild-type S. mutans. The results revealed that MVs from the ΔgtfBC mutant had no effect on C. albicans biofilm formation and exopolysaccharide production. In addition, C. albicans biofilm transcriptional regulators (Ndt80, Als1, Mnn9, Van1, Pmr1, Gca1, and Big1) expression were upregulated in S. mutans MV-treated group. In summary, the results of the present study showed that S. mutans MVs harboring glucosyltransferases involved in exopolysaccharide production augment C. albicans biofilm development, revealing a key role for S. mutans MVs in cross-kingdom interactions between S. mutans and C. albicans.}, } @article {pmid33042036, year = {2020}, author = {Wang, Y and Song, J and Zhang, F and Zeng, K and Zhu, X}, title = {Antifungal Photodynamic Activity of Hexyl-Aminolevulinate Ethosomes Against Candida albicans Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2052}, pmid = {33042036}, issn = {1664-302X}, abstract = {Biofilm formation is responsible for the development of chronic and recurrent Candida albicans infections. The generation of biofilms is commonly accompanied by high resistance to conventional antifungal drugs, which can increase up to 1,000-fold. Fortunately, antimicrobial photodynamic therapy (aPDT) has shown excellent potential to treat biofilm infections. However, the current most commonly used photosensitizer (PS), aminolevulinic acid (ALA), is hydrophilic, unstable, and has low permeability, leading to unsatisfactory effects on biofilm eradication. To solve these problems, more stable lipophilic PSs and more effective permeability carriers could be considered as two effective solutions. Hexyl-aminolevulinate (HAL) has good bioavailability as a PS, and we proved in a previous study that ethosomes (ES), lipid-based nanocarriers, promote percutaneous drug penetration. In our previous study, a HAL-ES system presented superior photodynamic effects compared to those of ALA or HAL alone. Therefore, here, we aim to evaluate the biological effects of HAL-ES-mediated aPDT on C. albicans biofilm. An XTT sodium salt assay showed that aPDT using 0.5% HAL decreased C. albicans biofilm activity by 69.71 ± 0.43%. Moreover, aPDT with 0.5% HAL-ES further decreased biofilm activity by 92.95 ± 0.16% and inhibited growth of 25.71 ± 1.61% within 48 h, mostly via its effect on the hyphae growth, which correlated with a three-fold increase in C. albicans plasma membrane permeabilization. Notably, HAL-ES-mediated aPDT significantly reduced the sessile minimum inhibitory concentration 50 (SMIC50) of fluconazole to <2.0 μg/ml, and the 21-day survival rate of C. albicans biofilm-infected mice increased from 6.7 to 73.3%. It also significantly reduced the drug resistance and in vivo pathogenicity of C. albicans biofilm. These results demonstrate that HAL-ES-mediated aPDT could be an effective therapy for C. albicans biofilm infections; while also serving as a particularly promising effective treatment for cutaneous or mucocutaneous candidiasis and the prevention of progression to systemic candidiasis.}, } @article {pmid33042035, year = {2020}, author = {Maali, Y and Journo, C and Mahieux, R and Dutartre, H}, title = {Microbial Biofilms: Human T-cell Leukemia Virus Type 1 First in Line for Viral Biofilm but Far Behind Bacterial Biofilms.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2041}, pmid = {33042035}, issn = {1664-302X}, abstract = {Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). To date, it is the unique published example of a virus able to form a biofilm at the surface of infected cells. Deeply studied in bacteria, bacterial biofilms represent multicellular assemblies of bacteria in contact with a surface and shielded by the extracellular matrix (ECM). Microbial lifestyle in biofilms, either viral or bacterial, is opposed structurally and physiologically to an isolated lifestyle, in which viruses or bacteria freely float in their environment. HTLV-1 biofilm formation is believed to be promoted by viral proteins, mainly Tax, through remodeling of the ECM of the infected cells. HTLV-1 biofilm has been linked to cell-to-cell transmission of the virus. However, in comparison to bacterial biofilms, very little is known on kinetics of viral biofilm formation or dissemination, but also on its pathophysiological roles, such as escape from immune detection or therapeutic strategies, as well as promotion of leukemogenesis. The switch between production of cell-free isolated virions and cell-associated viral biofilm, although not fully apprehended yet, remains a key step to understand HTLV-1 infection and pathogenesis.}, } @article {pmid33042032, year = {2020}, author = {Mohanta, YK and Biswas, K and Jena, SK and Hashem, A and Abd Allah, EF and Mohanta, TK}, title = {Corrigendum: Anti-biofilm and Antibacterial Activities of Silver Nanoparticles Synthesized by the Reducing Activity of Phytoconstituents Present in the Indian Medicinal Plants.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1784}, doi = {10.3389/fmicb.2020.01784}, pmid = {33042032}, issn = {1664-302X}, abstract = {[This corrects the article DOI: 10.3389/fmicb.2020.01143.].}, } @article {pmid33040243, year = {2021}, author = {Xu, Y and Li, H and Zeng, XC}, title = {A novel biofilm bioreactor derived from a consortium of acidophilic arsenite-oxidizing bacteria for the cleaning up of arsenite from acid mine drainage.}, journal = {Ecotoxicology (London, England)}, volume = {30}, number = {7}, pages = {1437-1445}, pmid = {33040243}, issn = {1573-3017}, support = {41472219//the General Programs from the National Natural Science Foundation of China/ ; }, mesh = {*Arsenites ; Bacteria/genetics ; Biofilms ; Bioreactors ; Oxidation-Reduction ; }, abstract = {Arsenite (As(III)) was considered to be of great concern in acid mine drainage (AMD). A promising approach for cleaning up of arsenite from AMD is microbial oxidation of As(III) followed by adsorptions. However, there is virtually no research about the acidophilic bioreactor for As(III) oxidation so far. In this study, we formed a new biofilm bioreactor with a consortium of acidophilic As(III) oxidation bacteria. It is totally chemoautotrophic, with no need to add any carbon or other materials during the operations. It works well under pH 3.0-4.0, capable of oxidizing 1.0-20.0 mg/L As(III) in 3.0-4.5 h, respectively. A continuous operation of the bioreactor suggests that it is very stable and sustainable. Functional gene detection indicated that the biofilms possessed a unique diversity of As(III) oxidase genes. Taken together, this acidophilic bioreactor has great potential for industrial applications in the cleaning up of As(III) from AMD solution.}, } @article {pmid33040179, year = {2021}, author = {Qian, Y and Xia, L and Wei, L and Li, D and Jiang, W}, title = {Artesunate inhibits Staphylococcus aureus biofilm formation by reducing alpha-toxin synthesis.}, journal = {Archives of microbiology}, volume = {203}, number = {2}, pages = {707-717}, pmid = {33040179}, issn = {1432-072X}, support = {81703568//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Artesunate/*pharmacology ; Bacterial Toxins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Gene Expression Regulation, Bacterial/drug effects ; Hemolysin Proteins/genetics/metabolism ; Hemolysis ; Rabbits ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/metabolism ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus is one of the most common pathogens in bacterial biofilm infections. Antibiotic treatment for infection caused by S. aureus biofilms is challenging, and few effective strategies have been developed to combat these infections. The aim of this study was to investigate the effect and possible mechanisms of artesunate on the biofilm formation of S. aureus. Bacterial growth curves were determined by a microtiter plate. Biofilm formation was determined by the crystal violet staining method and confocal laser scanning microscopy. Bacterial adhesion was assayed by the colony-counting method. The expression of virulence and adhesion genes was determined by real-time PCR. The hemolytic activity and expression of ɑ-hemolysin were analyzed using rabbit erythrocytes and Western blotting. The results showed that artesunate could significantly inhibit the biofilm formation of S. aureus in a dose-dependent manner. Artesunate could also inhibit bacterial adhesion and the expression of hla, RNAIII and agrA as well as ɑ-hemolysin production. The effect of artesunate on adhesion genes (clfA, clfB, fnbA, fnbB) had strain specificity, but it did not affect the expression of ica genes. The results indicated that artesunate might inhibit ɑ-hemolysin synthesis by the agr system, which inhibits biofilm formation.}, } @article {pmid33039892, year = {2021}, author = {Chen, S and Dougherty, M and Chen, Z and Zuo, X and He, J}, title = {Managing biofilm growth and clogging to promote sustainability in an intermittent sand filter (ISF).}, journal = {The Science of the total environment}, volume = {755}, number = {Pt 1}, pages = {142477}, pmid = {33039892}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Filtration ; Nitrogen ; *Sand ; Silicon Dioxide ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {The sustainability of rural sanitation includes the long-term welfare of both rural and urban societies. As a commonly used rural sanitation technology, operation of intermittent sand filters (ISF) is impacted by biofilm clogging inside the ISF. In this study ISF performance is studied at low hydraulic loading rates (HLR) to explore the interaction between biofilm growth and wastewater treatment efficiency. CW2D/HYDRUS, a simulation model which does not include media hydraulic property changes caused by biofilm growth, is utilized as a numerical control to contrast the effects of biofilm growth inside an experimental ISF. A paired experiment with simulation demonstrate that biofilm clogging comprised dominantly of heterotrophs occurred in the top layers of the ISF. Lowered HLR slows clogging development but not final clogging extent. The biofilm clogging development zone offers adequate removal of applied biodegradable COD and NH4[+] - N. However, the spatial distribution of heterotrophs and biodegradable COD does not match the denitrification requirement of the resulting NO3[-] - N. A simultaneous nitrification and denitrification (SND) potential is manifested in the clogging development zone, but lowered HLR reduces media moisture level to a less favorable level for denitrification. Furthermore, slowed water movement under lower HLR aggravates the accumulation of NO3[-] - N, which can potentially result in counterproductive salt accumulation. Since biofilm growth is a natural and self-adaptive response to wastewater application, this study suggests accepting limited, managed biofilm growth and clogging in ISFs. In addition, this study calls for further research to manage biofilm growth and clogging for long-term ISF sustainability.}, } @article {pmid33039857, year = {2021}, author = {Yuan, H and Wang, Y and Lai, Z and Zhang, X and Jiang, Z and Zhang, X}, title = {Analyzing microalgal biofilm structures formed under different light conditions by evaluating cell-cell interactions.}, journal = {Journal of colloid and interface science}, volume = {583}, number = {}, pages = {563-570}, doi = {10.1016/j.jcis.2020.09.057}, pmid = {33039857}, issn = {1095-7103}, mesh = {Biofilms ; Biomass ; Cell Communication ; Light ; *Microalgae ; }, abstract = {Biofilm structure plays an important role in microalgae biofilm-based culture. This work aims to understand microalgal biofilm structures formed under different light conditions. Here, Scenedesmus obliquus was biofilm cultured under the light spectra of white, blue, green, and red, and the photoperiods of 5:5 s, 30:30 min, and 12:12 h (light : dark period). Biofilms were observed with confocal laser scanning microscopes and profilometry, then the porosity and roughness of biofilm were determined. We found that cells under white light formed a heterogeneous biofilm with many voids, high porosity, and roughness. While under red and blue lights, cells formed homogeneous biofilms with low porosity. Biofilm structures formed under different photoperiods were different. The mechanism of forming different biofilm structures under different light conditions was interpreted from the aspect of cell-cell interactions. Moreover, the results revealed that biomass accumulation increased with the increasing biofilm porosity due to the high effective diffusion coefficient.}, } @article {pmid33039591, year = {2020}, author = {Wille, J and Teirlinck, E and Sass, A and Van Nieuwerburgh, F and Kaever, V and Braeckmans, K and Coenye, T}, title = {Does the mode of dispersion determine the properties of dispersed Pseudomonas aeruginosa biofilm cells?.}, journal = {International journal of antimicrobial agents}, volume = {56}, number = {6}, pages = {106194}, doi = {10.1016/j.ijantimicag.2020.106194}, pmid = {33039591}, issn = {1872-7913}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Load ; Biofilms/drug effects/growth & development ; Colistin/*pharmacology ; Cyclic GMP/*metabolism ; Drug Resistance, Bacterial/*physiology ; Humans ; Moths/microbiology ; Pseudomonas aeruginosa/*drug effects/metabolism/pathogenicity ; Tobramycin/*pharmacology ; }, abstract = {INTRODUCTION: Actively dispersed Pseudomonas aeruginosa biofilm cells differ from planktonic cells, as they have a lower intracellular cyclic di-guanosine monophosphate (c-di-GMP) concentration and show increased virulence. In addition, the nature of the dispersion trigger has been shown to influence the antibiotic susceptibility of dispersed cells. However, properties of passively-dispersed cells, in which the dispersion trigger directly releases cells from the biofilm, have not been described. The present study determined c-di-GMP concentration, virulence in Galleria mellonella and antibiotic susceptibility of P. aeruginosa cells dispersed from biofilm using various triggers.

MATERIALS AND METHODS: P. aeruginosa biofilms grown in flow-cells were dispersed actively [exposure to the nitric oxide (NO)-donor sodium nitroprusside (SNP) or to glutamate] or passively [by stopping and restarting the flow or exposure to laser-induced vapor nanobubbles (VNB)], and properties of these dispersed cells were compared to those of spontaneously-dispersed cells.

RESULTS: The passively dispersed P. aeruginosa biofilm cells had significantly lower intracellular c-di-GMP levels than actively-dispersed cells. However, this did not result in differences in virulence in Galleria mellonella, nor in tobramycin and ciprofloxacin susceptibility. Passively-dispersed cells were more susceptible to colistin than actively- and spontaneously-dispersed cells. In cells dispersed by interrupting the flow, increased susceptibility to colistin was immediate, whereas this was delayed for VNB-dispersed cells.

CONCLUSION: Passively-dispersed P. aeruginosa biofilm cells have a decreased intracellular c-di-GMP concentration and an increased colistin susceptibility compared to actively-dispersed cells. No differences in virulence or susceptibility to tobramycin or colistin were observed.}, } @article {pmid33037223, year = {2020}, author = {Dunn, MJ and Fillinger, RJ and Anderson, LM and Anderson, MZ}, title = {Automated quantification of Candida albicans biofilm-related phenotypes reveals additive contributions to biofilm production.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {36}, pmid = {33037223}, issn = {2055-5008}, support = {F31 DE029409/DE/NIDCR NIH HHS/United States ; R01 AI148788/AI/NIAID NIH HHS/United States ; }, mesh = {Automation ; Biofilms/*growth & development ; Candida albicans/genetics/isolation & purification/*physiology ; Candidiasis, Invasive/*microbiology ; Cell Adhesion ; Culture Media/chemistry ; Genome, Fungal ; High-Throughput Screening Assays ; Humans ; Mycology/*methods ; Phenotype ; Temperature ; }, abstract = {Biofilms are organized communities of microbial cells that promote persistence among bacterial and fungal species. Biofilm formation by host-associated Candida species of fungi occurs on both tissue surfaces and implanted devices, contributing to host colonization and disease. In C. albicans, biofilms are built sequentially by adherence of yeast to a surface, invasion into the substrate, the formation of aerial hyphal projections, and the secretion of extracellular matrix. Measurement of these biofilm-related phenotypes remains highly qualitative and often subjective. Here, we designed an informatics pipeline for quantifying filamentation, adhesion, and invasion of Candida species on solid agar media and utilized this approach to determine the importance of these component phenotypes to C. albicans biofilm production. Characterization of 23 C. albicans clinical isolates across three media and two temperatures revealed a wide range of phenotypic responses among isolates in any single condition. Media profoundly altered all biofilm-related phenotypes among these isolates, whereas temperature minimally impacted these traits. Importantly, the extent of biofilm formation correlated significantly with the additive score for its component phenotypes under some conditions, experimentally linking the strength of each component to biofilm mass. In addition, the response of the genome reference strain, SC5314, across these conditions was an extreme outlier compared to all other strains, suggesting it may not be representative of the species. Taken together, development of a high-throughput, unbiased approach to quantifying Candida biofilm-related phenotypes linked variability in these phenotypes to biofilm production and can facilitate genetic dissection of these critical processes to pathogenesis in the host.}, } @article {pmid33036210, year = {2020}, author = {Ya'ari, S and Halperin-Sternfeld, M and Rosin, B and Adler-Abramovich, L}, title = {Surface Modification by Nano-Structures Reduces Viable Bacterial Biofilm in Aerobic and Anaerobic Environments.}, journal = {International journal of molecular sciences}, volume = {21}, number = {19}, pages = {}, pmid = {33036210}, issn = {1422-0067}, support = {1732/17//Israel Science Foundation/ ; }, mesh = {Aerobiosis ; Anaerobiosis ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/metabolism ; *Bacterial Adhesion ; *Bacterial Physiological Phenomena ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry ; Enterococcus faecalis/drug effects/metabolism/physiology ; Nanostructures/*chemistry ; Phenylalanine/analogs & derivatives/chemistry ; Streptococcus mutans/drug effects/metabolism/physiology ; Surface Properties ; }, abstract = {Bacterial biofilm formation on wet surfaces represents a significant problem in medicine and environmental sciences. One of the strategies to prevent or eliminate surface adhesion of organisms is surface modification and coating. However, the current coating technologies possess several drawbacks, including limited durability, low biocompatibility and high cost. Here, we present a simple antibacterial modification of titanium, mica and glass surfaces using self-assembling nano-structures. We have designed two different nano-structure coatings composed of fluorinated phenylalanine via the drop-cast coating technique. We investigated and characterized the modified surfaces by scanning electron microscopy, X-ray diffraction and wettability analyses. Exploiting the antimicrobial property of the nano-structures, we successfully hindered the viability of Streptococcus mutans and Enterococcus faecalis on the coated surfaces in both aerobic and anaerobic conditions. Notably, we found lower bacteria adherence to the coated surfaces and a reduction of 86-99% in the total metabolic activity of the bacteria. Our results emphasize the interplay between self-assembly and antimicrobial activity of small self-assembling molecules, thus highlighting a new approach of biofilm control for implementation in biomedicine and other fields.}, } @article {pmid33035921, year = {2021}, author = {Parrino, B and Carbone, D and Cascioferro, S and Pecoraro, C and Giovannetti, E and Deng, D and Di Sarno, V and Musella, S and Auriemma, G and Cusimano, MG and Schillaci, D and Cirrincione, G and Diana, P}, title = {1,2,4-Oxadiazole topsentin analogs as staphylococcal biofilm inhibitors targeting the bacterial transpeptidase sortase A.}, journal = {European journal of medicinal chemistry}, volume = {209}, number = {}, pages = {112892}, doi = {10.1016/j.ejmech.2020.112892}, pmid = {33035921}, issn = {1768-3254}, mesh = {Aminoacyltransferases/*antagonists & inhibitors/metabolism ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/*antagonists & inhibitors/metabolism ; Biofilms/*drug effects ; Cell Line ; Cysteine Endopeptidases/metabolism ; Humans ; Imidazoles/chemistry/*pharmacology ; Indoles/chemistry/*pharmacology ; Oxadiazoles/chemistry/*pharmacology ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {The inhibition or prevention of biofilm formation represents an emerging strategy in the war against antibiotic resistance, interfering with key players in bacterial virulence. This approach includes the inhibition of the catalytic activity of transpeptidase sortase A (Srt A), a membrane enzyme responsible for covalently attaching a wide variety of adhesive matrix molecules to the peptidoglycan cell wall in Gram-positive strains. A new series of seventeen 1,2,4-oxadiazole derivatives was efficiently synthesized and screened as potential new anti-virulence agents. The ability of inhibiting biofilm formation was evaluated against both Gram-positive and Gram-negative pathogens. Remarkably, all these compounds inhibited S. aureus and/or P. aeruginosa biofilm formation in a dose dependent manner, with 50% biofilm inhibitory concentrations (BIC50s) below 10 μM for the most active compounds. Inhibition of SrtA was validated as one of the possible mechanisms of action of these new 1,2,4-oxadiazole derivatives, in the tested Gram-positive pathogen, using a specific enzymatic assay for a recombinant S. aureus SrtA. The three most active compounds, eliciting BIC50 values for S. aureus ATCC 25923 between 0.7 and 9.7 μM, showed a good activity toward the enzyme eliciting IC50 values ranging from 2.2 to 10.4 μM.}, } @article {pmid33035856, year = {2021}, author = {Shivaprasad, DP and Taneja, NK and Lakra, A and Sachdev, D}, title = {In vitro and in situ abrogation of biofilm formation in E. coli by vitamin C through ROS generation, disruption of quorum sensing and exopolysaccharide production.}, journal = {Food chemistry}, volume = {341}, number = {Pt 1}, pages = {128171}, doi = {10.1016/j.foodchem.2020.128171}, pmid = {33035856}, issn = {1873-7072}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Ascorbic Acid/administration & dosage/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects ; Carbon-Sulfur Lyases/genetics ; Cheese/microbiology ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial/drug effects ; Escherichia coli/*drug effects/physiology ; Food Handling ; Food Microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/*metabolism ; Quorum Sensing/drug effects ; Reactive Oxygen Species/metabolism ; }, abstract = {Emergence of antimicrobial drug-resistance amongst food-borne pathogens has led to severe deficit of available therapeutics and requires novel interventions. This study determined the activity of vitamin C (VitC), a natural antioxidant as powerful antibacterial agent against multidrug-resistant (MDR), biofilm-forming E. coli. Our findings revealed that VitC wield antibacterial action in dose-time dependent manner with minimum inhibitory concentration (MIC) of 125 mM. At these concentrations VitC impaired quorum sensing (QS) and exopolysaccharide (EPS) production and induced sugar and protein leakage from the bacterial cells by virtue of reactive oxygen species (ROS) generation. Furthermore, VitC-treated bacteria showed downregulation of genes underpinning biofilm signaling (luxS) and regulation (bssR) by up to 27-folds. Finally, this study demonstrated the promising antimicrobial application of VitC, in situ, in Indian soft cheese (paneer) when applied as a coating. Therefore, VitC can be applied as natural and safe 'antimicrobial' against biofilm-forming bacteria in food systems vis-à-vis other conventional antimicrobials.}, } @article {pmid33035584, year = {2020}, author = {Valliammai, A and Selvaraj, A and Sangeetha, M and Sethupathy, S and Pandian, SK}, title = {5-Dodecanolide inhibits biofilm formation and virulence of Streptococcus pyogenes by suppressing core regulons of virulence.}, journal = {Life sciences}, volume = {262}, number = {}, pages = {118554}, doi = {10.1016/j.lfs.2020.118554}, pmid = {33035584}, issn = {1879-0631}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony-Forming Units Assay ; Gene Expression Regulation, Bacterial ; Humans ; Streptococcus pyogenes/*drug effects/genetics/pathogenicity ; Virulence/drug effects/genetics ; }, abstract = {This study determined the antibiofilm and antivirulence potential of 5-Dodecanolide (DD) against an exclusive human pathogen Streptococcus pyogenes. Biofilm quantification assay showed antibiofilm efficacy of DD with maximum biofilm inhibition of 85% at 225 μg/mL concentration. Efficacy of antibacterial property of DD (225 μg/mL) was confirmed by CFU analysis and Alamar blue assay. Microscopic analyses evidently confirmed micro-colony formation, biofilm thickness and surface coverage were reduced upon DD treatment. In addition, based on the results of in vitro assays, it was noted that DD impaired the synthesis of surface hydrophobicity, slime, hyaluronic acid, hemolysin and protease production. Interestingly, DD increased the autoaggregation of S. pyogenes hence, facilitated enhanced recognition of clumped bacterial cells for innate immune clearance. The results were further validated by the reduced survival of DD treated S. pyogenes in healthy human blood. Consequently, based on the qPCR analysis DD altered the expression of core regulons srv, ropB, mga and genes associated with biofilm formation and virulence such as speB, dltA, srtB, sagA and slo. Hence, the overall results of the present study for the first time revealed the antibiofilm and antivirulence property of DD against clinically important pathogen S. pyogenes and further clinical investigations are required to assess the therapeutic use of DD.}, } @article {pmid33034553, year = {2020}, author = {Freel, KC and Fouteau, S and Roche, D and Farasin, J and Huber, A and Koechler, S and Peres, M and Chiboub, O and Varet, H and Proux, C and Deschamps, J and Briandet, R and Torchet, R and Cruveiller, S and Lièvremont, D and Coppée, JY and Barbe, V and Arsène-Ploetze, F}, title = {Effect of arsenite and growth in biofilm conditions on the evolution of Thiomonas sp. CB2.}, journal = {Microbial genomics}, volume = {6}, number = {10}, pages = {}, pmid = {33034553}, issn = {2057-5858}, mesh = {Adaptation, Physiological/genetics ; Arsenates/metabolism ; Arsenic/metabolism ; Arsenites/*metabolism ; Biofilms/*growth & development ; *Burkholderiales/genetics/growth & development/metabolism ; DNA Repair/genetics ; DNA Transposable Elements/genetics ; Evolution, Molecular ; Gene Expression Profiling ; Genetic Variation/genetics ; Genome, Bacterial/*genetics ; Genomic Islands/genetics ; Mining ; Whole Genome Sequencing ; }, abstract = {Thiomonas bacteria are ubiquitous at acid mine drainage sites and play key roles in the remediation of water at these locations by oxidizing arsenite to arsenate, favouring the sorption of arsenic by iron oxides and their coprecipitation. Understanding the adaptive capacities of these bacteria is crucial to revealing how they persist and remain active in such extreme conditions. Interestingly, it was previously observed that after exposure to arsenite, when grown in a biofilm, some strains of Thiomonas bacteria develop variants that are more resistant to arsenic. Here, we identified the mechanisms involved in the emergence of such variants in biofilms. We found that the percentage of variants generated increased in the presence of high concentrations of arsenite (5.33 mM), especially in the detached cells after growth under biofilm-forming conditions. Analysis of gene expression in the parent strain CB2 revealed that genes involved in DNA repair were upregulated in the conditions where variants were observed. Finally, we assessed the phenotypes and genomes of the subsequent variants generated to evaluate the number of mutations compared to the parent strain. We determined that multiple point mutations accumulated after exposure to arsenite when cells were grown under biofilm conditions. Some of these mutations were found in what is referred to as ICE19, a genomic island (GI) carrying arsenic-resistance genes, also harbouring characteristics of an integrative and conjugative element (ICE). The mutations likely favoured the excision and duplication of this GI. This research aids in understanding how Thiomonas bacteria adapt to highly toxic environments, and, more generally, provides a window to bacterial genome evolution in extreme environments.}, } @article {pmid33033618, year = {2020}, author = {Medina, WRM and Eramo, A and Tu, M and Fahrenfeld, NL}, title = {Sewer biofilm microbiome and antibiotic resistance genes as function of pipe material, source of microbes, and disinfection: field and laboratory studies.}, journal = {Environmental science : water research & technology}, volume = {6}, number = {8}, pages = {2122-2137}, pmid = {33033618}, issn = {2053-1400}, support = {R25 GM058389/GM/NIGMS NIH HHS/United States ; }, abstract = {Wastewater systems are recognized pathways for the spread of antibiotic resistant bacteria, but relatively little is known about the microbial ecology of the sewer environment. Sewer biofilm colonization by antibiotic resistance gene (ARG) carrying bacteria may impact interpretations of sewage epidemiology data, water quality during sewer overflows, and hazard to utility workers. The objectives of this research were to evaluate the (1) microbiome of real and simulated sewer biofilms and their potential to accumulate ARGs and (2) susceptibility of simulated sewer biofilms to bleach disinfection. First, biofilm samples were collected from sewer municipal systems. Next, an annular biofilm reactor was used to simulate the sewer environment while controlling the pipe material (concrete vs. PVC). The reactor was operated either as fed semi-batch with sewer sediment and synthetic wastewater (Sed-SB) or fed with a continuous flow of raw sewage (WW-CF). The abundance of ARGs, human fecal marker HF183, and 16S rRNA gene copies in these biofilm samples was measured with qPCR. Amplicon sequencing was performed to compare the prokaryotic diversity between samples. Finally, the susceptibility of reactor biofilm to a 4.6% bleach disnfection protocol was evaluated using viability qPCR and amplicon sequencing. Field and WW-CF biofilms contained the most ARG copies and the microbial community compositions varied between the different biofilm samples (field, Sed-SB, and WW-CF). Pipe material did not affect the abundance of ARGs in the reactor samples. However, log removal following bleach treatment suggested that the biofilm grown on PVC surface was primarily dislodged from the surface by the bleach treatment whereas more bacteria were lysed within the biofilm that remained on the concrete surface. Viable bacteria carrying ARGs were observed following 10 minutes of treatment. This study showed that sewer biofilms can accumulate bacteria carrying ARGs and that while bleach can reduce sewer biofilm density, the protocol tested here will not completely remove the biofilms.}, } @article {pmid33032216, year = {2021}, author = {Zhou, Y and Kiely, PD and Kibbee, R and Ormeci, B}, title = {Effect of polymeric support material on biofilm development, bacterial population, and wastewater treatment performance in anaerobic fixed-film systems.}, journal = {Chemosphere}, volume = {264}, number = {Pt 1}, pages = {128477}, doi = {10.1016/j.chemosphere.2020.128477}, pmid = {33032216}, issn = {1879-1298}, mesh = {Anaerobiosis ; Bacteria/genetics ; *Biofilms ; Bioreactors ; Phosphorus ; Waste Disposal, Fluid ; *Water Purification ; }, abstract = {This study evaluated the performance of high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyvinylchloride (PVC), polypropylene (PP), polyvinylidene fluoride (PVDF) and polymethyl methacrylate (acrylic) when used as a support media in anaerobic attached-growth wastewater treatment systems. A combination of physical and chemical (total solids, protein, phosphorus, ammonia, chemical oxygen demand) methods, environmental scanning electron microscopy (ESEM) and Live/Dead viability assay) and genetic sequencing over a period of 81 days was used to provide an in-depth understanding of the impact of different polymer materials on biofilm formation, bacteria population, and wastewater treatment performance. The results showed that hydrophobic polymeric materials (i.e., PP and PVDF) promoted initial cell adhesion and biofilm formation (<16 days) better than the hydrophilic (i.e., ABS and HDPE) polymeric materials. However, under longer-term and steady-state operation (after 81 days), the hydrophilic materials demonstrated larger mature biofilm quantities and better wastewater treatment performance. The sequencing data showed biofilm bacterial community structures of the ABS and HDPE to be significantly different compared to the other polymeric materials tested. The data showed a positive correlation as well between the phyla present on the ABS and HDPE and COD removal. These results suggest that the type of polymeric material play an important role in biofilm development, bacterial population diversity, and wastewater treatment performance for anaerobic fixed-film systems, and ABS and HDPE performed better than the widely used PVC in the industry.}, } @article {pmid33027987, year = {2020}, author = {O'Shaughnessy, M and McCarron, P and Viganor, L and McCann, M and Devereux, M and Howe, O}, title = {The Antibacterial and Anti-biofilm Activity of Metal Complexes Incorporating 3,6,9-Trioxaundecanedioate and 1,10-Phenanthroline Ligands in Clinical Isolates of Pseudomonas Aeruginosa from Irish Cystic Fibrosis Patients.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {33027987}, issn = {2079-6382}, abstract = {Chronic infections of Pseudomonas aeruginosa in the lungs of cystic fibrosis (CF) patients are problematic in Ireland where inherited CF is prevalent. The bacteria's capacity to form a biofilm in its pathogenesis is highly virulent and leads to decreased susceptibility to most antibiotic treatments. Herein, we present the activity profiles of the Cu(II), Mn(II) and Ag(I) tdda-phen chelate complexes {[Cu(3,6,9-tdda)(phen)2].3H2O.EtOH} n (Cu-tdda-phen), {[Mn(3,6,9-tdda)(phen)2].3H2O.EtOH} n (Mn-tdda-phen) and [Ag2(3,6,9-tdda)(phen)4].EtOH (Ag-tdda-phen) (tddaH2 = 3,6,9-trioxaundecanedioic acid; phen = 1,10-phenanthroline) towards clinical isolates of P. aeruginosa derived from Irish CF patients in comparison to two reference laboratory strains (ATCC 27853 and PAO1). The effects of the metal-tdda-phen complexes and gentamicin on planktonic growth, biofilm formation (pre-treatment) and mature biofilm (post-treatment) alone and in combination were investigated. The effects of the metal-tdda-phen complexes on the individual biofilm components; exopolysaccharide, extracellular DNA (eDNA), pyocyanin and pyoverdine are also presented. All three metal-tdda-phen complexes showed comparable and often superior activity to gentamicin in the CF strains, compared to their activities in the laboratory strains, with respect to both biofilm formation and established biofilms. Combination studies presented synergistic activity between all three complexes and gentamicin, particularly for the post-treatment of established mature biofilms, and was supported by the reduction of the individual biofilm components examined.}, } @article {pmid33025721, year = {2021}, author = {Kumari, S and Mangwani, N and Das, S}, title = {Naphthalene catabolism by biofilm forming marine bacterium Pseudomonas aeruginosa N6P6 and the role of quorum sensing in regulation of dioxygenase gene.}, journal = {Journal of applied microbiology}, volume = {130}, number = {4}, pages = {1217-1231}, doi = {10.1111/jam.14867}, pmid = {33025721}, issn = {1365-2672}, support = {BT/PR/17390/BCE/8/1158/2016//Department of Biotechnology , Ministry of Science and Technology/ ; BT/PR14998/GBD/27/279/2010//Department of Biotechnology , Ministry of Science and Technology/ ; }, mesh = {Biodegradation, Environmental ; *Biofilms/drug effects/growth & development ; Dioxygenases/*genetics/metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Multienzyme Complexes/*genetics/metabolism ; Naphthalenes/*metabolism ; Pseudomonas aeruginosa/genetics/growth & development/metabolism/*physiology ; Quorum Sensing/drug effects/*physiology ; Soil Pollutants/metabolism ; Tannins/pharmacology ; }, abstract = {AIM: This study aims to establish the role of quorum sensing (QS) system on the regulation of naphthalene ring cleaving gene ndo (encoding naphthalene dioxygenase) in biofilm forming marine bacterium Pseudomonas aeruginosa N6P6 for naphthalene degradation.

METHODS AND RESULTS: Total cell count of P. aeruginosa N6P6 during biofilm mode of growth was slightly higher (7·3 × 10[8]  CFU per ml) than its planktonic mid-exponential phase culture (4·7 × 10[8]  CFU per ml). Naphthalene degradation in 20h by biofilm (48-h old) and planktonic culture was 99·4 ± 0·002% and 77 ± 3·25%, respectively. Pseudomonas aeruginosa N6P6 was able to degrade 64·3 ± 4·7% naphthalene in sterile soil microcosm in 24 h. The bacterium showed the presence of 136 bp ndo gene which was upregulated in a dose-dependent manner in presence of naphthalene. QS inhibitor (QSI) tannic acid downregulated the expression of ndo gene, naphthalene 1, 2-dioxygenase (N12O) enzyme activity and naphthalene degradation (by biofilm culture).

CONCLUSIONS: P. aeruginosa N6P6 shows chemotaxis towards naphthalene and adapts well in terrestrial environment for naphthalene degradation.

This study provides the information that the QS plays crucial role in biofilm formation in P. aeruginosa N6P6 and QS regulatory genes subsequently control the ndo gene for enzymatic degradation of naphthalene.}, } @article {pmid33025548, year = {2020}, author = {Oh, MH and Han, K}, title = {AbaR is a LuxR type regulator essential for motility and the formation of biofilm and pellicle in Acinetobacter baumannii.}, journal = {Genes & genomics}, volume = {42}, number = {11}, pages = {1339-1346}, doi = {10.1007/s13258-020-01005-8}, pmid = {33025548}, issn = {2092-9293}, support = {HI17C1657//Ministry of Health and Welfare/ ; }, mesh = {Acinetobacter baumannii/*genetics/growth & development ; Biofilms/*growth & development ; Cell Movement/*genetics ; Humans ; Quorum Sensing/genetics ; Repressor Proteins/*genetics ; Trans-Activators/*genetics ; }, abstract = {BACKGROUND: Acinetobacter baumannii is a major opportunistic pathogen causing nosocomial infections. Acinetobacter baumannii possesses a quorum sensing system consisting of abaI, encoding an autoinducer synthase, and abaR, encoding a putative LuxR type regulator. AbaI is required for motility and biofilm formation in A. baumannii. However, the functions of AbaR on the expression of abaI, motility, and the formation of biofilm and pellicle have not yet been explored.

OBJECTIVE: The aim of this study was to investigate the effects of abaR mutation on the expression of abaI, motility, and the formation of biofilm and pellicle.

METHODS: Functions of AbaR were assessed by the construction of an isogenic mutant and by evaluating the effects of abaR mutation on the expression of abaI, motility, and the formation of biofilm and pellicle.

RESULTS: The abaR mutant revealed a significant decrease in the expression of abaI. The disruption of abaR resulted in substantial defects in motility and the formation of biofilm and pellicle. Introduction of abaR in trans complemented the defects.

CONCLUSIONS: AbaR of A. baumannii is required for the expression of abaI and plays important roles in motility and the formation of biofilm and pellicle. AbaR may be considered to be a target of anti-biofilm agents.}, } @article {pmid33025062, year = {2021}, author = {Baeza, N and Mercade, E}, title = {Relationship Between Membrane Vesicles, Extracellular ATP and Biofilm Formation in Antarctic Gram-Negative Bacteria.}, journal = {Microbial ecology}, volume = {81}, number = {3}, pages = {645-656}, pmid = {33025062}, issn = {1432-184X}, support = {CTQ2014-59632-R//Ministerio de Ciencia, Innovación y Universidades/ ; BES-2015-074582//Ministerio de Ciencia, Innovación y Universidades/ ; 2014SGR1017//Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya/ ; }, mesh = {Adenosine Triphosphate ; Antarctic Regions ; Biofilms ; *Extracellular Vesicles ; Gram-Negative Bacteria ; *Shewanella ; }, abstract = {Biofilms offer a safe environment that favors bacterial survival; for this reason, most pathogenic and environmental bacteria live integrated in biofilm communities. The development of biofilms is complex and involves many factors, which need to be studied in order to understand bacterial behavior and control biofilm formation when necessary. We used a collection of cold-adapted Antarctic Gram-negative bacteria to study whether their ability to form biofilms is associated with a capacity to produce membrane vesicles and secrete extracellular ATP. In most of the studied strains, no correlation was found between biofilm formation and these two factors. Only Shewanella vesiculosa M7[T] secreted high levels of extracellular ATP, and its membrane vesicles caused a significant increase in the speed and amount of biofilm formation. In this strain, an important portion of the exogenous ATP was contained in membrane vesicles, where it was protected from apyrase treatment. These results confirm that ATP influences biofilm formation. Although the role of extracellular ATP in prokaryotes is still not well understood, the metabolic cost of its production suggests it has an important function, such as a role in biofilm formation. Thus, the liberation of extracellular ATP through membrane vesicles and its function deserve further study.}, } @article {pmid33024198, year = {2020}, author = {Yao, Y and Pu, Y and Ngan, WY and Kan, K and Pan, J and Li, M and Habimana, O}, title = {Effects of sodium citrate on the structure and microbial community composition of an early-stage multispecies biofilm model.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {16585}, pmid = {33024198}, issn = {2045-2322}, mesh = {Bacteria/*drug effects ; Bacterial Physiological Phenomena ; Biofilms/*drug effects ; Carbon/analysis ; *Coculture Techniques ; Culture Media/chemistry ; Microbial Interactions ; Microbiota/*drug effects/*physiology ; Nutrients/analysis ; Sodium Citrate/*pharmacology ; Water ; }, abstract = {In recent years, most biofilm studies have focused on fundamental investigations using multispecies biofilm models developed preferentially in simulated naturally occurring low-nutrient medium than in artificial nutrient-rich medium. Because biofilm development under low-nutrient growth media is slow, natural media are often supplemented with an additional carbon source to increase the rate of biofilm formation. However, there are knowledge gaps in interpreting the effects of such supplementation on the resulting biofilm in terms of structure and microbial community composition. We investigated the effects of supplementation of a simulated freshwater medium with sodium citrate on the resulting structure, bacterial community composition, and microbial network interactions of an early-stage multispecies biofilm model. Qualitative and quantitative analyses of acquired confocal laser scanning microscopy data confirmed that sodium citrate supplementation distinctly increased biofilm biomass. Sequencing data revealed that the microbial community structure of biofilms grown in sodium citrate-supplemented conditions was characterized with increased relative abundance and dominance of Proteobacteria compared with that of biofilms grown in sodium citrate-free conditions. Our findings suggest that the supplementation of a low-nutrient medium with a carbon source in experiments involving multispecies biofilms may lead to structural and compositional biases of the microbial community, causing changes in biofilm phenotype.}, } @article {pmid33022915, year = {2020}, author = {Abd El-Hamid, MI and Y El-Naenaeey, ES and M Kandeel, T and Hegazy, WAH and Mosbah, RA and Nassar, MS and Bakhrebah, MA and Abdulaal, WH and Alhakamy, NA and Bendary, MM}, title = {Promising Antibiofilm Agents: Recent Breakthrough against Biofilm Producing Methicillin-Resistant Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {33022915}, issn = {2079-6382}, abstract = {Multidrug resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) is a superbug pathogen that causes serious diseases. One of the main reasons for the lack of the effectiveness of antibiotic therapy against infections caused by this resistant pathogen is the recalcitrant nature of MRSA biofilms, which results in an increasingly serious situation worldwide. Consequently, the development of innovative biofilm inhibitors is urgently needed to control the biofilm formation by this pathogen. In this work, we thus sought to evaluate the biofilm inhibiting ability of some promising antibiofilm agents such as zinc oxide nanoparticles (Zno NPs), proteinase K, and hamamelitannin (HAM) in managing the MRSA biofilms. Different phenotypic and genotypic methods were used to identify the biofilm producing MDR MRSA isolates and the antibiofilm/antimicrobial activities of the used promising agents. Our study demonstrated strong antibiofilm activities of ZnO NPs, proteinase K, and HAM against MRSA biofilms along with their transcriptional modulation of biofilm (intercellular adhesion A, icaA) and quorum sensing (QS) (agr) genes. Interestingly, only ZnO NPs showed a powerful antimicrobial activity against this pathogen. Collectively, we observed overall positive correlations between the biofilm production and the antimicrobial resistance/agr genotypes II and IV. Meanwhile, there was no significant correlation between the toxin genes and the biofilm production. The ZnO NPs were recommended to be used alone as potent antimicrobial and antibiofilm agents against MDR MRSA and their biofilm-associated diseases. On the other hand, proteinase-K and HAM can be co-administrated with other antimicrobial agents to manage such types of infections.}, } @article {pmid33022530, year = {2020}, author = {Zhang, X and Zhang, Z and Liu, Y and Hao Ngo, H and Guo, W and Wang, H and Zhang, Y and Zhang, D}, title = {Impacts of sulfadiazine on the performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor system at different C/N ratios.}, journal = {Bioresource technology}, volume = {318}, number = {}, pages = {124180}, doi = {10.1016/j.biortech.2020.124180}, pmid = {33022530}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Extracellular Polymeric Substance Matrix ; Membranes, Artificial ; Sewage ; Sulfadiazine ; }, abstract = {The performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system was evaluated when exposed to 0.5 mg/L of antibiotic sulfadiazine (SDZ). Results indicated that although SDZ reduced the removal efficiency of NH4[+]-N and TN (up to 12%) and TOC (up to 6%) at low C/N (2.5 and 4), it had no significant effect at high C/N (6 and 9). It was found that SDZ was removed 75% and 58% at high C/N of 9 and low C/N of 2.5, respectively. SDZ decreased the ratio of volatile biomass/total biomass and sludge particle size and increased the concentrations of extracellular polymeric substance (EPS) and soluble microbial product (SMP) in MBR. Consequently, this accelerated the membrane fouling rates, with an average increase of 6.85 kPa/d at low C/N (2.5) and 0.513-0.701 kPa/d at medium and high C/N (4, 6 and 9).}, } @article {pmid33021681, year = {2021}, author = {Haque, MM and Haque, MA and Mosharaf, MK and Marcus, PK}, title = {Novel bacterial biofilm consortia that degrade and detoxify the carcinogenic diazo dye Congo red.}, journal = {Archives of microbiology}, volume = {203}, number = {2}, pages = {643-654}, pmid = {33021681}, issn = {1432-072X}, support = {Project ID: LS2018751//Ministry of Education, Bangladesh/ ; }, mesh = {Bacteria/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Carcinogens/metabolism ; Congo Red/*metabolism ; Inactivation, Metabolic ; Wastewater/chemistry ; }, abstract = {Free-living planktonic single bacterial strain can decolorize Congo red (CR) but often produces the carcinogenic, mutagenic and genotoxic aromatic amines. Planktonic single and bacterial consortia are more susceptible to toxic pollutants than their biofilm counterparts. In the present study, four biofilm consortia (C1 = Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304, C2 = Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201, C3 = E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401, and C4 = E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were prepared and assessed for bioremediation of CR. All these biofilm consortia remarkably decolorized (96.9 to 99.5%) the CR (100 mg/L) in static condition within 72 h incubation at 28 °C. These consortia also synthesized significantly more intracellular azoreductase and laccase enzyme than extracellular of these enzymes. UV-Vis spectral analysis revealed that the major peak at 478 nm wavelength of CR was completely disappeared. FTIR analysis showed several major peaks along with azo bonds are completely or partly disappeared, deformed or widened. Chemical oxygen demand was reduced by 86.4, 85.5, 87.0 and 86.2% by C1, C2, C3 and C4, respectively. Accordingly, biodegraded metabolites of CR by different biofilm consortia did not inhibit the germination of wheat seeds and bacterial growth. Thus, these biofilm consortia can be applied in bioremediation of wastewater containing CR for safe disposal into the environment. To our knowledge, this is the first report on degradation and detoxification of aqueous solution containing CR by bacterial biofilm consortia.}, } @article {pmid33021210, year = {2020}, author = {Silva Júnior, VV and Raposo, BL and Lopes, ACS and Araújo, PSR and Fontes, A and Cabral Filho, PE and Maciel, MAV}, title = {Activity of carbonyl cyanide-3-chlorophenylhydrazone on biofilm formation and antimicrobial resistance in Pseudomonas aeruginosa using quantum dots-meropenem conjugates as nanotools.}, journal = {Methods and applications in fluorescence}, volume = {8}, number = {4}, pages = {045005}, doi = {10.1088/2050-6120/aba7a2}, pmid = {33021210}, issn = {2050-6120}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial ; Hydrazones/*pharmacology ; Meropenem/chemical synthesis/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Quantum Dots/*chemistry ; }, abstract = {Hospital infections associated with multidrug-resistant (MDR) Pseudomonas aeruginosa are a worldwide public health problem. Efflux systems and biofilm formation are mechanisms related to resistance to carbapenemics. In this study, quantum dots (QDs) were used to evaluate the effect of carbonyl cyanide-3-chlorophenylhydrazone (CCCP), an efflux pump system inhibitor, on biofilm formation and antimicrobial resistance profile of P. aeruginosa strains. For this, QDs were covalently conjugated to meropenem (MPM) and incubated with a P. aeruginosa resistant isolate (P118) or a control sensitive strain (ATCC Pa27853). P118 was also analyzed with conjugates after previous CCCP efflux inhibitor incubation. Fluorescence microscopy images showed that both sensitive and resistant bacteria were efficiently labeled. Nevertheless, P118 isolates presented fluorescent cell agglomerates, suggesting biofilm formation. The addition of the CCCP changed the labeling profile of the resistant isolate, and the absence of agglomerates was observed, indicating no biofilm formation. Genetic assays revealed the presence of MexA and MexE genes encoding channel proteins from efflux pump systems in both resistant and sensitive strains. Disk-diffusion and broth microdilution tests determined drug susceptibility profiles in the presence and absence of CCCP for P118 isolates. We verified that the CCCP efflux system inhibitor may contribute to P. aeruginosa resistant phenotype reduction for some antimicrobials. This study verified the efficiency of QD-MPM conjugates to trigger and study biofilm formation, or its inhibition, before and after CCCP addition. QDs conjugated to antimicrobials can be used as nanotools to investigate multidrug-resistant bacterial strains on biofilm formation.}, } @article {pmid33020729, year = {2020}, author = {Thongsricome, T and Kanjanabuch, T and Maeboonruen, N and Pavatung, P and Katavetin, P and Eiam-Ong, S}, title = {Promising effect of in-situ lyticase enzyme therapy on peritoneal dialysis catheter obstruction from Acremonium fungal biofilm: A case report.}, journal = {Medical mycology case reports}, volume = {30}, number = {}, pages = {26-28}, pmid = {33020729}, issn = {2211-7539}, abstract = {We reported the first clinical use of lyticase enzyme in salvaging the peritoneal dialysis (PD) catheter obstruction from Acremonium fungal biofilm during the COVID-19 pandemic era with an impressive result in PD patient presenting with fungal peritonitis and ultrafiltration failure. The organism species was disclosed from PD effluent and catheter cultures. Adjuvant treatment with in-situ lyticase may be considered for catheter salvage therapy if the catheter could not promptly removed in time.}, } @article {pmid33020559, year = {2020}, author = {Wickramasinghe, NN and Hlaing, MM and Ravensdale, JT and Coorey, R and Chandry, PS and Dykes, GA}, title = {Characterization of the biofilm matrix composition of psychrotrophic, meat spoilage pseudomonads.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {16457}, pmid = {33020559}, issn = {2045-2322}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Extracellular Polymeric Substance Matrix/metabolism ; Food Microbiology/methods ; Meat/*microbiology ; Pseudomonas/*growth & development/metabolism ; Pseudomonas fragi/*growth & development/metabolism ; Temperature ; }, abstract = {Psychrotrophic Pseudomonas species are the key spoilage bacteria of aerobically stored chilled meat. These organisms readily form biofilms on meat under refrigerated conditions leading to consumer rejection and associated economic losses. Limited information is available on the matrix composition of the biofilms formed by these bacteria. We quantified and characterized the main components of the matrix of mono-species biofilms of selected Pseudomonas fragi and Pseudomonas lundensis strains using chemical analysis and Raman spectroscopy. The biofilms were grown at 10 °C and 25 °C on nitro-cellulose membranes placed on surface sterilized beef cuts. Extra-cellular polymeric substances of the matrix were extracted in soluble and bound forms and were chemically assessed for total carbohydrates, proteins and extra-cellular DNA. Both Pseudomonas species showed a significant increase in total carbohydrates and total proteins when grown at 10 °C as compared to 25 °C. Extra-cellular DNA did not show a strong correlation with growth temperature. Raman spectra were obtained from planktonic bacteria and membrane grown biofilms at 10 °C and 25 °C. Higher levels of guanine were detected in planktonic cells as compared to biofilm cells. This study suggests that psychrotrophic Pseudomonas species may respond to cold stress by increasing extra-cellular polymer secretions.}, } @article {pmid33020355, year = {2020}, author = {Millones-Gómez, PA and Maurtua-Torres, D and Bacilio-Amaranto, R and Calla-Poma, RD and Requena-Mendizabal, MF and Valderrama-Negron, AC and Calderon-Miranda, MA and Calla-Poma, RA and Huauya Leuyacc, ME}, title = {Antimicrobial Activity and Antiadherent Effect of Peruvian Psidium guajava (Guava) Leaves on a Cariogenic Biofilm Model.}, journal = {The journal of contemporary dental practice}, volume = {21}, number = {7}, pages = {733-740}, pmid = {33020355}, issn = {1526-3711}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms ; Dental Caries/*drug therapy ; Humans ; Peru ; Plant Leaves ; *Psidium ; }, abstract = {AIM: Phytomedicine has been commonly practiced as a form of traditional medicine in various cultures for the treatment of oral diseases. Recently, it has gained importance as an alternative to conventional treatment. Several extracts of plants and fruits have been recently evaluated for their potential activity against microorganisms involved in the development of dental caries. The purpose of this study was to evaluate the antimicrobial activity and antiadherent effect of the crude organic extract (COE) and three partitions (aqueous, butanolic, and chloroformic) of Psidium guajava (guava) leaves on a cariogenic biofilm model.

MATERIALS AND METHODS: Guava leaves were obtained from the mountains of northern Peru, where they grow wild and free of pesticides. The antimicrobial activity of the COEs and partitions against Streptococcus mutans and Streptococcus gordonii was determined by measuring the inhibition halos, while the effect on biofilm adhesion was determined by measuring the optical density using spectrophotometry.

RESULTS: An antibacterial effect of the COE and chloroformic partition against S. gordonii (p < 0.05) was found, as was a significant effect on biofilm adherence, with a minimum inhibitory concentration (MIC) of 0.78 mg/mL, which was maintained throughout the 7 days of evaluation.

CONCLUSION: We conclude that the COEs and their chloroformic partition have antimicrobial and antibiotic effects against this strain of S. gordonii, making them of particular interest for evaluation as a promising alternative for the prevention of dental caries.

CLINICAL SIGNIFICANCE: By knowing the antimicrobial effect of Psidium guajava, this substance can be effectively used in products aimed to prevent dental caries and periodontal disease.}, } @article {pmid33019733, year = {2020}, author = {Ramos, LS and Silva, LN and Branquinha, MH and Santos, ALS}, title = {Susceptibility of the Candida haemulonii Complex to Echinocandins: Focus on Both Planktonic and Biofilm Life Styles and a Literature Review.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {33019733}, issn = {2309-608X}, support = {01//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 01//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 01//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; }, abstract = {Candida haemulonii complex (C. haemulonii, C. duobushaemulonii and C. haemulonii var. vulnera) is well-known for its resistance profile to different available antifungal drugs. Although echinocandins are the most effective class of antifungal compounds against the C. haemulonii species complex, clinical isolates resistant to caspofungin, micafungin and anidulafungin have already been reported. In this work, we present a literature review regarding the effects of echinocandins on this emergent fungal complex. Published data has revealed that micafungin and anidulafungin were more effective than caspofungin against the species forming the C. haemulonii complex. Subsequently, we investigated the susceptibilities of both planktonic and biofilm forms of 12 Brazilian clinical isolates of the C. haemulonii complex towards caspofungin and micafungin (anidulafungin was unavailable). The planktonic cells of all the fungal isolates were susceptible to both of the test echinocandins. Interestingly, echinocandins caused a significant reduction in the biofilm metabolic activity (viability) of almost all fungal isolates (11/12, 91.7%). Generally, the biofilm biomasses were also affected (reduction range 20-60%) upon exposure to caspofungin and micafungin. This is the first report of the anti-biofilm action of echinocandins against the multidrug-resistant opportunistic pathogens comprising the C. haemulonii complex, and unveils the therapeutic potential of these compounds.}, } @article {pmid33017531, year = {2020}, author = {Silva, IA and de Souza Araújo, IJ and Stipp, RN and Puppin Rontani, RM}, title = {Glass-ionomer cement modifies the gene expression of Streptococcus mutans providing a lower virulent biofilm.}, journal = {American journal of dentistry}, volume = {33}, number = {5}, pages = {273-276}, pmid = {33017531}, issn = {0894-8275}, mesh = {Biofilms ; Glass Ionomer Cements/*pharmacology ; Streptococcus mutans/*genetics ; Sucrose ; Virulence ; }, abstract = {PURPOSE: To evaluate the effect of glass-ionomer cement (GIC) on gene expression (gtfC, gtfD, covR, and vicR) of Streptococcus mutans (S. mutans) biofilms at 2, 4 and 24 hours.

METHODS: Six groups were tested according to the materials and time observation, as follows: ceramic (IPS Empress Esthetic), as the control group, and GIC (Ketac Molar Easymix); and time points of S. mutans biofilm formation (2, 4, and 24 hours). Round-shaped samples (10 x 2 mm) of each material were prepared according to the manufacturers' specifications. GIC discs were handled in a laminar flow hood under aseptic conditions and stored at 100% relative humidity at 37°C for 24 hours to complete setting reaction. The samples were placed in a 24-well plate and immersed in 1.5 ml BHI + 1% sucrose with an inoculum of S. mutans UA159 to allow biofilm growth during 2, 4, and 24 hours. Next, the samples were removed, vortexed and centrifuged to collect cell pellets (n=5) for each material and time point. Pellets were stored at -80°C. Then, RNA was purified using the RNeasy Mini Kit protocol. The RNA was converted in cDNA using iScript cDNA Synthesis according to the manufacturer's recommendations. Analysis of gtfC, gtfD, vicR, and covR expressions was performed using Step One Real-Time qPCR device with specific primers for each gene and the analysis normalized by 16S reference gene expression. Data from gtfC, gtfD, and vicR were analyzed by t-test to compare between groups while Mann-Whitney was used to analyze covR expression (α= 0.05).

RESULTS: No significant differences at 2 and 4 hours between materials for all analyzed genes were noted. However, in the 24-hour period, a significant decrease in gtfC and vicR expressions were observed, while covR expression increased when GIC was compared to ceramic.

CLINICAL SIGNIFICANCE: The use of glass-ionomer cement decreased the virulence of S. mutans biofilms, which may imply a reduced bacterial cariogenic potential.}, } @article {pmid33015594, year = {2020}, author = {Crone, BC and Sorial, GA and Pressman, JG and Ryu, H and Keely, SP and Brinkman, N and Bennett-Stamper, C and Garland, JL}, title = {Design and evaluation of degassed anaerobic membrane biofilm reactors for improved methane recovery.}, journal = {Bioresource technology reports}, volume = {10}, number = {}, pages = {100407}, pmid = {33015594}, issn = {2589-014X}, support = {EPA999999/ImEPA/Intramural EPA/United States ; }, abstract = {Anaerobic treatment of domestic wastewater (DWW) produces dissolved methane that needs to be recovered for use as an energy product. Membrane-based recovery systems have been reported in the literature but are often limited by fouling. The objective of this study was to develop a methane producing biofilm on the shell side surface a membrane to allow for immediate recovery of methane as it was produced, negating mass transfer resistance caused by fouling. Between 89 and 96% of total methane produced was recovered via in-situ degassing without the need for fouling control or cleaning throughout 72 weeks of operation. High methane recovery efficiencies led to predictions of net positive energy yield in one reactor and a 32-61% reduction in energy demand in the others compared to the control. This research demonstrates the feasibility and usefulness of combining attached growth anaerobic wastewater treatment processes with hollow fiber membrane methane recovery systems for improved operation.}, } @article {pmid33013801, year = {2020}, author = {Li, M and Gašparovič, H and Weng, X and Chen, S and Korduláková, J and Jessen-Trefzer, C}, title = {The Two-Component Locus MSMEG_0244/0246 Together With MSMEG_0243 Affects Biofilm Assembly in M. smegmatis Correlating With Changes in Phosphatidylinositol Mannosides Acylation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {570606}, pmid = {33013801}, issn = {1664-302X}, abstract = {Ferric and ferrous iron is an essential transition metal for growth of many bacterial species including mycobacteria. The genomic region msmeg_0234 to msmeg_0252 from Mycobacterium smegmatis is putatively involved in iron/heme metabolism. We investigate the genes encoding the presumed two component system MSMEG_0244/MSMEG_0246, the neighboring gene msmeg_0243 and their involvement in this process. We show that purified MSMEG_0243 indeed is a heme binding protein. Deletion of msmeg_0243/msmeg_0244/msmeg_0246 in Mycobacterium smegmatis leads to a defect in biofilm formation and colony growth on solid agar, however, this phenotype is independent of the supplied iron source. Further, analysis of the corresponding mutant and its lipids reveals that changes in morphology and biofilm formation correlate with altered acylation patterns of phosphatidylinositol mannosides (PIMs). We provide the first evidence that msmeg_0244/msmeg_0246 work in concert in cellular lipid homeostasis, especially in the maintenance of PIMs, with the heme-binding protein MSMEG_0243 as potential partner.}, } @article {pmid33013797, year = {2020}, author = {Bottagisio, M and Barbacini, P and Bidossi, A and Torretta, E and deLancey-Pulcini, E and Gelfi, C and James, GA and Lovati, AB and Capitanio, D}, title = {Phenotypic Modulation of Biofilm Formation in a Staphylococcus epidermidis Orthopedic Clinical Isolate Grown Under Different Mechanical Stimuli: Contribution From a Combined Proteomic Study.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {565914}, pmid = {33013797}, issn = {1664-302X}, abstract = {One of the major causes of prosthetic joint failure is infection. Recently, coagulase negative Staphylococcus epidermidis has been identified as an emergent, nosocomial pathogen involved in subclinical prosthetic joint infections (PJIs). The diagnosis of PJIs mediated by S. epidermidis is usually complex and difficult due to the absence of acute clinical signs derived from the host immune system response. Therefore, analysis of protein patterns in biofilm-producing S. epidermidis allows for the examination of the molecular basis of biofilm formation. Thus, in the present study, the proteome of a clinical isolate S. epidermidis was analyzed when cultured in its planktonic or sessile form to examine protein expression changes depending on culture conditions. After 24 h of culture, sessile bacteria exhibited increased gene expression for ribosomal activity and for production of proteins related to the initial attachment phase, involved in the capsular polysaccharide/adhesin, surface associated proteins and peptidoglycan biosynthesis. Likewise, planktonic S. epidermidis was able to aggregate after 24 h, synthesizing the accumulation associate protein and cell-wall molecules through the activation of the YycFG and ArlRS, two component regulatory pathways. Prolonged culture under vigorous agitation generated a stressful growing environment triggering aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. Further studies will be essential to support these findings in order to further delineate the complex mechanisms of biofilm formation of S. epidermidis and they could provide the groundwork for the development of new drugs against biofilm-related infections, as well as the identification of novel biomarkers of subclinical or chronic infections mediated by these emerging, low virulence pathogens.}, } @article {pmid33013788, year = {2020}, author = {Liu, X and Li, Z and Fan, Y and Lekbach, Y and Song, Y and Xu, D and Zhang, Z and Ding, L and Wang, F}, title = {A Mixture of D-Amino Acids Enhances the Biocidal Efficacy of CMIT/MIT Against Corrosive Vibrio harveyi Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {557435}, pmid = {33013788}, issn = {1664-302X}, abstract = {Biocides are widely used for the mitigation of microbial contamination, especially in the field of the aviation fuel industry. However, the long-term use of biocide has raised the concerns regarding the environmental contamination and microbial drug resistance. In this study, the effect of a mixture of D-amino acids (D-tyrosine and D-methionine) on the enhancement of the bactericidal effect of 5-Chloro-2-Methyl-4-isothiazolin-3-one/2-Methyl-2H-isothiazole-3-one (CMIT/MIT) against corrosive Vibrio harveyi biofilm was evaluated. The results revealed that D-Tyr and D-Met alone can enhance the biocidal efficacy of CMIT/MIT, while the treatment of 5 ppm CMIT/MIT, 1 ppm D-Tyr and 100 ppm D-Met showed the best efficacy comparable to that of 25 ppm CMIT/MIT alone. The triple combination treatment successfully prevented the establishment of the corrosive V. harveyi biofilm and effectively removed the mature V. harveyi biofilm. These conclusions were confirmed by the results of sessile cell counts, images obtained by scanning electron microscope and confocal laser scanning microscope, and the ATP test kit.}, } @article {pmid33013719, year = {2020}, author = {Wang, F and Deng, L and Huang, F and Wang, Z and Lu, Q and Xu, C}, title = {Flagellar Motility Is Critical for Salmonella enterica Serovar Typhimurium Biofilm Development.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1695}, pmid = {33013719}, issn = {1664-302X}, abstract = {The food-borne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) causes self-limiting gastroenteritis in humans and is not easily eradicated because it often attaches to suitable surfaces to form biofilms that have high resistance to disinfectants and antimicrobials. To develop an alternative strategy for the treatment of biofilms, it is necessary to further explore the effects of flagellar motility on the development process of Salmonella biofilms. Here, we constructed flagella mutants (ΔflgE and ΔfliC) to systematically study this process. By comparing them with wild-type strains, we found that these mutants lacking flagellar motility form fewer biofilms in the early stage, and the formed mature biofilms contain more cells and extracellular polymeric substances (EPS). In addition, fewer mutant cells adhered to glass plates compared with wild-type cells even after 6 h of incubation, suggesting that flagellar motility plays a significant role in preliminary cell-surface interactions. More importantly, the motility of wild-type strain was greatly decreased when they were treated with carbonyl cyanide m-chlorophenylhydrazone, which inhibited flagellar motility and reduced biofilm formation, as in the case of the ΔflgE mutant. Overall, these findings suggest that flagellar motility plays an important role in Salmonella biofilm initiation and maturation, which can help us to counteract the mechanisms involved in biofilm formation and to develop more rational control strategies.}, } @article {pmid33011901, year = {2021}, author = {Wu, D and Li, X and Yu, Y and Gong, B and Zhou, X}, title = {Heparin stimulates biofilm formation of Escherichia coli strain Nissle 1917.}, journal = {Biotechnology letters}, volume = {43}, number = {1}, pages = {235-246}, pmid = {33011901}, issn = {1573-6776}, support = {31670120//National Natural Science Foundation of China/ ; }, mesh = {Biofilms/*drug effects ; *Escherichia coli/drug effects/growth & development ; Heparin/*pharmacology ; Salmonella typhimurium/drug effects/growth & development ; }, abstract = {OBJECTIVES: Escherichia coli strain Nissle 1917 (EcN), a gut probiotic competing with pathogenic bacteria, has been used to attenuate various intestinal dysfunctions. Heparin is a sulfated glycosaminoglycan enriched in the human and animal intestinal mucosa, which has a close connection with bacterial biofilm formation. However, the characteristics of heparin affecting bacterial biofilm formation remain obscure. In this study, we investigated the influence of heparin and its derivatives on EcN biofilm formation.

RESULTS: Here, we found that heparin stimulated EcN biofilm formation in a dose-dependent manner. With the addition of native heparin, the EcN biofilm formation increased 6.9- to 10.8-fold than that without heparin, and was 1.4-, 3.1-, 3.0-, and 3.8-fold higher than that of N-desulfated heparin (N-DS), 2-O-desulfated heparin (2-O-DS), 6-O-desulfated heparin (6-O-DS), and N-/2-O-/6-O-desulfated heparin (N-/2-O-/6-O-DS), respectively. Depolymerization of heparin produced chain-shortened heparin fragments with decreased molecular weight. The depolymerized heparins did not stimulate EcN biofilm formation. The OD570 value of EcN biofilm with the addition of chain-shortened heparin fragments was 8.7-fold lower than that of the native heparin. Furthermore, the biofilm formation of Salmonella enterica serovar Typhimurium was also investigated with the addition of heparin derivatives, and the results were consistent with that of EcN biofilm formation.

CONCLUSIONS: We conclude that heparin stimulated EcN biofilm formation. Both the sulfation and chain-length of heparin contributed to the enhancement of EcN biofilm formation. This study increases the understanding of how heparin affects biofilm formation, indicating the potential role of heparin in promoting intestinal colonization of probiotics that antagonize pathogen infections.}, } @article {pmid33010891, year = {2020}, author = {Yu, Z and Zhang, J and Ding, M and Wu, S and Shuangjia Li, and Zhang, M and Yin, J and Meng, Q}, title = {SspA positively controls exopolysaccharides production and biofilm formation by up-regulating the algU expression in Pseudoalteromonas sp. R3.}, journal = {Biochemical and biophysical research communications}, volume = {533}, number = {4}, pages = {988-994}, doi = {10.1016/j.bbrc.2020.09.118}, pmid = {33010891}, issn = {1090-2104}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; DNA-Binding Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Microscopy, Electron, Scanning ; Multigene Family ; Mutation ; Polysaccharides, Bacterial/*biosynthesis ; Pseudoalteromonas/genetics/*physiology/ultrastructure ; Sigma Factor/genetics/metabolism ; Up-Regulation ; }, abstract = {Biofilm formation enhances the survival and persistence of microorganisms in response to environmental stresses. It has been revealed that stringent starvation protein A (SspA) can function as an important regulator dealing with environmental stresses for bacterial survival. However, the connection between SspA and biofilm formation is essentially unclear yet. In this study, we presented evidence showing SspA positively controls biofilm formation by up-regulating exopolysaccharides (EPS) production in marine bacterium Pseudoalteromonas sp. R3. Both qPCR and lacZ reporter system congruously revealed that SspA positively controls the expression of EPS biosynthesis gene cluster. Unlike generally accepted thought that SspA regulates bacterial physiology by inhibiting the expression of histone-like nucleotide structuring protein (H-NS) gene, the function of SspA on EPS production and biofilm formation in Pseudoalteromonas sp. R3 is H-NS-independent. Instead, SspA positively regulates the expression of sigma factor AlgU-encoding gene, thus affecting EPS biosynthesis and biofilm formation. In view of the important role of SspA in biofilm formation, we believe that the improvement of tolerance to marine environmental stresses could be related to tuning of SspA-involved biofilm formation.}, } @article {pmid33010587, year = {2021}, author = {Selvaraj, A and Valliammai, A and Premika, M and Priya, A and Bhaskar, JP and Krishnan, V and Pandian, SK}, title = {Sapindus mukorossi Gaertn. and its bioactive metabolite oleic acid impedes methicillin-resistant Staphylococcus aureus biofilm formation by down regulating adhesion genes expression.}, journal = {Microbiological research}, volume = {242}, number = {}, pages = {126601}, doi = {10.1016/j.micres.2020.126601}, pmid = {33010587}, issn = {1618-0623}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Gene Expression/*drug effects ; Genes, Bacterial/genetics ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Oleic Acid/chemistry/*pharmacology ; Plant Extracts/*pharmacology ; Polymerase Chain Reaction ; Sapindus/*chemistry ; Spectroscopy, Fourier Transform Infrared ; Virulence Factors/genetics ; }, abstract = {Plants are boon to the mankind due to plenty of metabolites with medicinal values. Though plants have traditionally been used to treat various diseases, their biological values are not completely explored yet. Sapindus mukorossi is one such ethnobotanical plant identified for various biological activities. As biofilm formation and biofilm mediated drug resistance of methicillin-resistant Staphylococcus aureus (MRSA) have raised as serious global issue, search for antibiofilm agents has gained greater importance. Notably, antibiofilm potential of S. mukorossi is still unexplored. The aim of the study is to explore the effect of S. mukorossi methanolic extract (SMME) on MRSA biofilm formation and adhesive molecules production. Significantly, SMME exhibited 82 % of biofilm inhibition at 250 μg/mL without affecting the growth and microscopic analyses evidenced the concentration dependent antibiofilm activity of SMME. In vitro assays exhibited the reduction in slime, cell surface hydrophobicity, autoaggregation, extracellular polysaccharides substance and extracellular DNA synthesis upon SMME treatment. Further, qPCR analysis confirmed the ability of SMME to interfere with the expression of adhesion genes associated with biofilm formation such as icaA, icaD, fnbA, fnbB, clfA, cna, and altA. GC-MS analysis and molecular docking study revealed that oleic acid is responsible for the antibiofilm activity. FT-IR analysis validated the presence of oleic acid in SMME. These results suggest that SMME can be used as a promising therapeutic agent against MRSA biofilm-associated infections.}, } @article {pmid33010367, year = {2020}, author = {Oliveira-Júnior, JB and da Silva, EM and Veras, DL and Ribeiro, KRC and de Freitas, CF and de Lima, FCG and Gutierrez, SJC and Camara, CA and Barbosa-Filho, JM and Alves, LC and Brayner, FA}, title = {Antimicrobial activity and biofilm inhibition of riparins I, II and III and ultrastructural changes in multidrug-resistant bacteria of medical importance.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104529}, doi = {10.1016/j.micpath.2020.104529}, pmid = {33010367}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Chlorocebus aethiops ; *Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; *Staphylococcus aureus ; Vero Cells ; }, abstract = {Natural products have been used to treat various infections; however, the development of antimicrobials has made natural products in disuse. Riparin I, II and III are natural alkamide isolated from Aniba riparia (Ness) Mez (Lauraceae), that exhibit economic importance and it is used in traditional medicine, and popularly known as "louro". This study investigated the cytotoxicity, antimicrobial and antibiofilm activity, and ultrastructural changes in vitro by riparins I, II and III in Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. We analyzed the cytotoxicity by MTT assay in Vero cells and hemolytic action verified in human erythrocytes. The antimicrobial activity was determined by microdilution in broth against ATCC strains, identifying the susceptible species. Subsequently, only the MDR isolates of sensitive bacterial species were evaluated regarding its biofilm formation and ultrastructural changes. Riparin I presented low cytotoxicity and hemolytic percentage ranging from of 9.01%-12.97%. Only the riparin III that showed antimicrobial activity against MDR clinical isolates, and significant reduction in biofilm formation in S. aureus. Moreover, the riparin III promoted ultrastructural changes in bacterial cells, such as elongated cellular without bacterial septum, cells with a rugged appearance on the cell surface and cytoplasmic material extravasation. As has been noted riparin III has an inhibitory potential against biofilm formation in S. aureus, besides having antimicrobial activity and promoting ultrastructural changes in MDR clinical isolates. Thus, riparin III is an interesting alternative for further studies aiming to develop new therapeutic options.}, } @article {pmid33010007, year = {2021}, author = {Molham, F and Khairalla, AS and Azmy, AF and El-Gebaly, E and El-Gendy, AO and AbdelGhani, S}, title = {Anti-Proliferative and Anti-Biofilm Potentials of Bacteriocins Produced by Non-Pathogenic Enterococcus sp.}, journal = {Probiotics and antimicrobial proteins}, volume = {13}, number = {2}, pages = {571-585}, pmid = {33010007}, issn = {1867-1314}, mesh = {*Anti-Infective Agents/pharmacology ; *Antineoplastic Agents/pharmacology ; *Bacteriocins/genetics/pharmacology ; Biofilms ; Caco-2 Cells ; Cell Proliferation ; Enterococcus/genetics/*physiology ; Humans ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The incidence of cancer is increasing worldwide; likewise, the emergence of antibiotic-resistant biofilm-forming pathogens has led to a tremendous increase in morbidity and mortality. This study aimed to evaluate the probiotic properties of bacteriocin-producing Enterococcus sp. with a focus on their anti-biofilm and anticancer activities. Three of 79 Enterococcus isolates (FM43, FM65, FM50) were identified as producers of broad-spectrum bioactive molecules and were molecularly characterized as Enterococcus faecium by 16S rRNA sequencing. Phenotypic and genotypic screening for potential virulence factors revealed no factors known to promote pathogenicity. Treatment with proteinase K resulted in diminished antimicrobial activity; PCR-based screening for bacteriocin genes suggested the presence of both entA and entB genes that encode enterocins A and B, respectively. Maximum antimicrobial activity was detected during the early stationary phase, while activity disappeared after 24 h in culture. Bacteriocins from these isolates were stable at high temperatures and over a wide range of pH. Interestingly, crude supernatants of Ent. faecium FM43 and Ent. faecium FM50 resulted in significant destruction (80% and 48%, respectively; P < 0.05) of Streptococcus mutans ATCC 25175-associated preformed biofilms. Moreover, in vitro cytotoxicity assays revealed that extracts from Ent. faecium isolates FM43, FM65, and FM50 inhibited Caco-2 cell proliferation by 76.9%, 70%, and 85.3%, respectively. Taken together, the multifunctional capabilities of the microbial-derived proteins identified in our study suggest potentially important roles as alternative treatments for biofilm-associated infections and cancer.}, } @article {pmid33007505, year = {2021}, author = {Liu, B and Sun, M and Lu, F and Du, C and Li, X}, title = {Study of biofilm-influenced corrosion on X80 pipeline steel by a nitrate-reducing bacterium, Bacillus cereus, in artificial Beijing soil.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {197}, number = {}, pages = {111356}, doi = {10.1016/j.colsurfb.2020.111356}, pmid = {33007505}, issn = {1873-4367}, mesh = {*Bacillus cereus ; Beijing ; Biofilms ; Corrosion ; Nitrates ; Soil ; *Steel ; }, abstract = {The biofilm of Bacillus cereus on the surface of X80 pipeline steel was investigated from forming to shedding. Based on the observed biofilm morphology and pit analysis, it was found that B. cereus biofilm could stimulate X80 pipeline steel pitting corrosion, which was attributed to the nitrate reduction of bacteria beneath the biofilm. Electrochemical measurements and general corrosion rate results showed that B. cereus biofilm can better accelerate X80 pipeline steel corrosion compared to sterile solutions. Interestingly, the results also showed that thick biofilms had a slight tendency to inhibit the general corrosion process compared with its formation and exfoliation, which was confirmed by scanning Kelvin probe. The corrosion rate of X80 pipeline steel in artificial Beijing soil is closely related to the state of the biofilm, and nitrate reducing bacteria accelerates the occurrence of pits. The corresponding corrosion mechanisms are proposed.}, } @article {pmid33007485, year = {2020}, author = {Qu, X and Yang, H and Jia, B and Yu, Z and Zheng, Y and Dai, K}, title = {Biodegradable Zn-Cu alloys show antibacterial activity against MRSA bone infection by inhibiting pathogen adhesion and biofilm formation.}, journal = {Acta biomaterialia}, volume = {117}, number = {}, pages = {400-417}, doi = {10.1016/j.actbio.2020.09.041}, pmid = {33007485}, issn = {1878-7568}, mesh = {Absorbable Implants ; *Alloys/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Rats ; Staphylococcus aureus ; Zinc/pharmacology ; }, abstract = {Bone and joint-related infections remain the primary and most critical complications of orthopedic surgery. We have innovatively prepared Zn-Cu alloys to achieve outstanding material and antibacterial properties. In this study, we systematically assessed the material properties and antibacterial activity of these Zn-Cu alloys. Our results showed that the Zn-2Cu alloy had the best mechanical properties, biocompatibility, and osteogenic properties. Findings of microbial cultures, CLSM, SEM, and TEM indicated that Zn-2Cu alloy can inhibit both coagulase-positive and coagulase-negative staphylococci, as well as antibiotic-resistant strains (MRSA and MRSE), by preventing the bacteria adhesion and the biofilm formation. Zn-2Cu alloy could broadly affect the expression of MRSA genes associated with adhesion, autolysis, biofilm formation, virulence, and drug resistance. A rat femur intramedullary nail infection-prevention model was established and the Zn-2Cu alloy-treated group showed significant antibacterial activity against MRSA and reduced the inflammatory toxic side-effects and infection-related bone loss. Collectively, our results indicate the potential utility of Zn-Cu alloy implants with 2 wt% Cu in treating orthopedic infections. Statement of significance: Osteomyelitis is a serious complication of orthopedic surgeries. Wide use of antibiotics contributes to the appearance of multi-drug resistant strains like methicillin-resistant staphylococcus aureus (MRSA). Alternatively, anti-osteomyelitis implants with broad-spectrum antibacterial properties can be favorable. Here, the antibacterial performance of biodegradable Zn-Cu alloys was evaluated with four different bacteria strains including antibiotic-resistant strains (MRSA and MRSE). Zn-Cu alloys exert excellent bacterial killing capability in all strains. In a rat femur infection model, the alloy showed significant antibacterial activity against MRSA and reduced inflammatory toxic side-effects as well as infection-related bone loss. The antibacterial property of Zn-2Cu alloy was associated with inhibition of gene expression related to wall synthesis, adhesion, colonization, biofilm formation, autolysis, and secretion of virulence factors in MRSA.}, } @article {pmid33006773, year = {2021}, author = {Farmer, BD and Fuller, SA and Beck, BH and Abernathy, JW and Lange, MD and Webster, CD}, title = {Differential susceptibility of white bass (Morone chrysops), striped bass (Morone saxatilis) and hybrid striped bass (M. chrysops × M. saxatilis) to Flavobacterium columnare and effects of mucus on bacterial growth and biofilm development.}, journal = {Journal of fish diseases}, volume = {44}, number = {2}, pages = {161-169}, doi = {10.1111/jfd.13272}, pmid = {33006773}, issn = {1365-2761}, support = {6028-31630-008-00-D//Agricultural Research Service/ ; }, mesh = {Animals ; Bass ; Biofilms/growth & development ; Fish Diseases/genetics/*microbiology ; Flavobacteriaceae Infections/genetics/microbiology/*veterinary ; Flavobacterium/*growth & development ; Gills/microbiology ; Mucus/*microbiology ; }, abstract = {Columnaris disease generates substantial losses of many freshwater fish species; one is the hybrid striped bass. The ubiquitous aquatic bacterium Flavobacterium columnare can be highly effective in biofilm formation on fish skin and gills. Previous research showed a difference between columnaris disease susceptibility of hybrid striped bass (Morone saxatilis × M. chrysops) and white bass (M. chrysops). To understand these differential susceptibilities and possible mucosal relationship, we assessed total bacterial growth and biofilm formation with mucus derived from each moronid parental species: white bass and striped bass (M. saxatilis). Differential susceptibility was confirmed of the other parent species, the striped bass (M. saxatilis). In addition to intraspecies investigations, individual hybrid striped bass mucosal affects were also studied for deferential responses to bacterial growth and biofilm formation. Species- and concentration-dependent differences were detected in the total growth of the bacteria to host mucus. Our data suggest that bass mucus can significantly affect biofilm formation with the F. columnare isolate tested. There appears to be a correlation between the bacteria's response of growth and biofilms and bass species susceptibility. This study provides insight into our understanding of the host-pathogen interaction between F. columnare and moronids.}, } @article {pmid33006097, year = {2020}, author = {Duraisamy, S and Balakrishnan, S and Ranjith, S and Husain, F and Sathyan, A and Peter, AS and Prahalathan, C and Kumarasamy, A}, title = {Bacteriocin-a potential antimicrobial peptide towards disrupting and preventing biofilm formation in the clinical and environmental locales.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {36}, pages = {44922-44936}, pmid = {33006097}, issn = {1614-7499}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriocins ; Biofilms ; Peptides ; *Pharmaceutical Preparations ; }, abstract = {Biofilm, a consortium of microbial cells, protected by extracellular polymeric matrix, is considered a global challenge due to the inherent antibiotic resistance conferred by its lifestyle. Besides, it poses environmental threats causing huge damage in food industries, fisheries, refineries, water systems, pharmaceutical industries, medical industries, etc. Living in a community of microbial populations is most critical in the clinical field, making it responsible for about 80% of severe and chronic microbial diseases. The necessity to find an alternative approach is the need of the hour to solve these crises. So far, many approaches have been attempted to disrupt the initial stage of biofilm formation, including adherence and maturation. Bacteriocins are a group of antimicrobial peptides, produced by bacteria having the potential to disrupt biofilm either by itself or in combination with other drugs than antibiotic counterparts. A clear understanding on mechanisms of bacterial biofilm formation, progression, and resistance will surely lead to the development of innovative, effective biofilm control strategies in pharmaceutical, health care industries and environmental locales.}, } @article {pmid33005670, year = {2020}, author = {Raheel, IAER and Hassan, WH and Salem, SSR and Salam, HSH}, title = {Biofilm forming potentiality of Escherichia coli isolated from bovine endometritis and their antibiotic resistance profiles.}, journal = {Journal of advanced veterinary and animal research}, volume = {7}, number = {3}, pages = {442-451}, pmid = {33005670}, issn = {2311-7710}, abstract = {OBJECTIVE: The objectives of this study were to determine the biofilm-forming capability and antimicrobial susceptibility of Escherichia coli recovered from bovine endometritis samples.

MATERIALS AND METHODS: A total of 120 uterine specimens were collected from cows suffering from endometritis for bacteriological examination. Antimicrobial susceptibility testing was carried out for all isolated E. coli by using the disc diffusion method. The isolates were phenotypically studied for biofilm-forming ability by cultivation on yeast extract -casamino acids Congo red agar (CRA). Some randomly selected isolates were chosen for the molecular identification of some virulence and resistance genes.

RESULTS: A total of 58(48.3%) E. coli isolates could be isolated from the 120 samples. Antimicrobial susceptibility testing exhibited that 91.4%, 79.3%, 79.3%, 74.1%, and 58.6% of the isolates were sensitive to gentamicin, amoxicillin-clavulanic acid, ciprofloxacin, cephalexin, and sulfamethoxazole- trimethoprim, respectively. On the other hand, 91.4% and 70.7% isolates were resistant to cefotaxime and doxycycline, respectively. Cultivation on CRA revealed that 46.6% of isolates were biofilm producers. The molecular detection of resistance and virulence genes declared that all isolates harbored bla TEM, sul1, tetA, qnrS, bla CTX-M , and fimH with a percentage of 100%, papC (40%), and hlyA (10%). FimH was the most prevalent biofilm-associated gene.

CONCLUSION: The present study highlights the high prevalence of multi-drug- resistant E. coli associated with bovine endometritis. The detection of the fimH gene is circumstantial evidenced that this gene has a crucial role in biofilm formation in intrauterine pathogenic E. coli.}, } @article {pmid33004721, year = {2020}, author = {Zahir, S and Pal, TK and Sengupta, A and Biswas, S and Bar, S}, title = {Effect of Aerva sanguinolenta (Lal bishalyakarani) plant extract on biofilm-induced human enamel demineralization: An in vitro study.}, journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry}, volume = {38}, number = {3}, pages = {238-246}, doi = {10.4103/JISPPD.JISPPD_312_20}, pmid = {33004721}, issn = {1998-3905}, mesh = {*Amaranthaceae ; Biofilms ; *Dental Caries ; Dental Enamel ; Humans ; Plant Extracts/pharmacology ; Tooth Demineralization/*prevention & control ; }, abstract = {BACKGROUND: Controlling cariogenic biofilm formation by plant extracts could add to preventive strategies to dental caries.

OBJECTIVE: To evaluate in vitro the role of Aerva Sanguinolenta ethanolic extract on biofilm-induced microbial human enamel demineralization.

METHODOLOGY: The prepared enamel sections of study group (SG), positive control group (PCG), and negative control group (NCG) were immersed in 2 ml of 0.2% ethanolic extract of A. sanguinolenta, 0.12% chlorhexidine, and distilled water, respectively, for 2 min before subjecting to closed batch culture technique utilizing mono- or dual-species culture media of Streptococcus mutans and Lactobacillus acidophilus. Quantification of biofilm and demineralization of enamel was performed by crystal violet (CV) assay and scanning electron microscope (SEM) attached to energy-dispersive X-ray analysis, respectively.

STATISTICAL ANALYSIS: Two-way ANOVA and Tukey's test were used for analysis.

RESULTS: CV assay of biofilm recorded the highest and lowest optical absorbance value in NC3 (2.728660) and PC3 (0.364200), respectively. Thus, biofilm formation is highest in NCG and lowest among PCG. Surface roughness and porosity in enamel are greatest among NCG and lowest among SG as evident by SEM. Wt% of calcium (S3 47.7170) and phosphorus ion (S3 22.7330) was highest in SG, closely resembling that of B enamel (Ca = 41.9530, P = 19.6650). Wt% of oxygen is lowest in SG (S3 28.8920) and resembles baseline O2 (37.4950). Thus, the amount of biofilm formation is moderate and amount of demineralization of enamel is least among SGs.

CONCLUSION: Enamel exposed to 2 ml of 0.2% solution of A. sanguinolenta for 2 min could fairly inhibit formation of biofilm and positively inhibit underlying demineralization in cariogenic environment.}, } @article {pmid33002803, year = {2021}, author = {Zhu, Z and Shan, L and Zhang, X and Hu, F and Zhong, D and Yuan, Y and Zhang, J}, title = {Effects of bacterial community composition and structure in drinking water distribution systems on biofilm formation and chlorine resistance.}, journal = {Chemosphere}, volume = {264}, number = {Pt 1}, pages = {128410}, doi = {10.1016/j.chemosphere.2020.128410}, pmid = {33002803}, issn = {1879-1298}, mesh = {Biofilms ; Chlorine/pharmacology ; *Disinfectants/pharmacology ; Disinfection ; *Drinking Water ; Water Microbiology ; Water Supply ; }, abstract = {Community-intrinsic properties affect the composition and function of a microbial community. Understanding the microbial community-intrinsic properties in drinking water distribution systems (DWDS) could help to select disinfection strategies and aid in the prevention of waterborne infectious diseases. In this study, we investigated the formation of multi-species biofilms in six groups, each consisting of four or five mixed bacterial strains isolated from a simulated DWDS, at different incubation times (24, 48, and 72 h). We then evaluated the chlorine resistance of the 72-h multi-species biofilms in the presence of 0.3, 0.6, 1, 2, 4, and 10 mg/L residual chlorine. Microbacterium laevaniformans inhibited the formation of multi-species biofilms, Sphingomonas sp., Acinetobacter sp. and A. deluvii had the effect of promoting their growth, and B. cereus has little effect on the growth of multi-species biofilms. However, these inhibition and promotion effects were weak and inadequate to completely control the growth of multi-species biofilms. All multi-species produced strong biofilms after 72 h incubation, which could be due to microbial community-intrinsic properties. Community-intrinsic properties could maintain high EPS production and cell-to-cell connections in multi-species biofilms, and could affect the formation of multi-species biofilms. The chlorine resistance of multi-species biofilms was significantly improved by B. cereus, but significantly reduced by M. laevaniformans. These results indicated that the microbial community-intrinsic properties were influenced by the environment. At a relatively low disinfectant concentration (<2 mg/L residual chlorine), the community-intrinsic properties were maintained; however, when the disinfectant concentration was increased to 2-4 mg/L residual chlorine, the community-intrinsic properties weakened, and significantly affected the resistance of the microbial communities to the disinfectant. With further increases in concentration, to >4 mg/L residual chlorine, no significant difference was observed in the disinfectant resistance of the microbial community.}, } @article {pmid33000552, year = {2020}, author = {Rieusset, L and Rey, M and Muller, D and Vacheron, J and Gerin, F and Dubost, A and Comte, G and Prigent-Combaret, C}, title = {Secondary metabolites from plant-associated Pseudomonas are overproduced in biofilm.}, journal = {Microbial biotechnology}, volume = {13}, number = {5}, pages = {1562-1580}, pmid = {33000552}, issn = {1751-7915}, mesh = {Acyl-Butyrolactones ; Bacteria ; *Biofilms ; *Pseudomonas/genetics ; Rhizosphere ; }, abstract = {Plant rhizosphere soil houses complex microbial communities in which microorganisms are often involved in intraspecies as well as interspecies and inter-kingdom signalling networks. Some members of these networks can improve plant health thanks to an important diversity of bioactive secondary metabolites. In this competitive environment, the ability to form biofilms may provide major advantages to microorganisms. With the aim of highlighting the impact of bacterial lifestyle on secondary metabolites production, we performed a metabolomic analysis on four fluorescent Pseudomonas strains cultivated in planktonic and biofilm colony conditions. The untargeted metabolomic analysis led to the detection of hundreds of secondary metabolites in culture extracts. Comparison between biofilm and planktonic conditions showed that bacterial lifestyle is a key factor influencing Pseudomonas metabolome. More than 50% of the detected metabolites were differentially produced according to planktonic or biofilm lifestyles, with the four Pseudomonas strains overproducing several secondary metabolites in biofilm conditions. In parallel, metabolomic analysis associated with genomic prediction and a molecular networking approach enabled us to evaluate the impact of bacterial lifestyle on chemically identified secondary metabolites, more precisely involved in microbial interactions and plant-growth promotion. Notably, this work highlights the major effect of biofilm lifestyle on acyl-homoserine lactone and phenazine production in P. chlororaphis strains.}, } @article {pmid33000364, year = {2020}, author = {Zhang, J and Wang, H and Xie, T and Huang, Q and Xiong, X and Liu, Q and Wang, G}, title = {The YmdB protein regulates biofilm formation dependent on the repressor SinR in Bacillus cereus 0-9.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {11}, pages = {165}, doi = {10.1007/s11274-020-02933-z}, pmid = {33000364}, issn = {1573-0972}, support = {31572047//National Nature Science Foundation of China/ ; 31701831//This study was funded by National Nature Science Foundation of China (NSFC)/ ; }, mesh = {Amino Acid Sequence ; Bacillus cereus/*genetics/*metabolism ; Bacillus subtilis/genetics/metabolism ; Bacterial Proteins/*genetics/*metabolism ; *Biofilms ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; }, abstract = {YmdB, which can regulate biofilm formation independently, has been reported to exist in Bacillus subtilis. The B. cereus 0-9 genome also encodes a YmdB-like protein, which has measureable phosphodiesterase activity, and 72.35% sequence identity to YmdB protein of B. subtilis 168. In this work, we studied the function of YmdB protein and its encoding gene, ymdB, in B. cereus 0-9. Our results indicated that YmdB protein is critical for the biofilm formation of B. cereus 0-9. In ΔymdB mutant, the transcriptional levels of sinR and hag were up-regulated, and those of genes closely related to biofilm formation, such as sipW, tasA and calY, were down-regulated. Deletion of ymdB gene stimulates the swarming motility of B. cereus 0-9, and enhances it to travel outward, but reduces its ability to form complex spatial structures on the solid surface of MSgg plates. Hence, it is considered that YmdB plays a key role in biofilm formation, and this effect is likely achieved through the function of repressor SinR in B. cereus 0-9. Furthermore, by comparing the amino acid sequences of YmdB by Basic Local Alignment Search Tool (BLAST) in Genebank, we found that YmdB homologues are present in a variety of bacteria (Including Gram-negative bacteria) except B. subtilis and B. cereus. All these bacteria come at different evolutionary distances and belong to different genera. Therefore, we believe that YmdB exists in many types of bacteria and plays an important role in the stress-resistance of bacteria to adapt to the environment. These results can help us to further understand the biocontrol characteristics of B. cereus 0-9.}, } @article {pmid32998606, year = {2020}, author = {Aoki, M and Kowada, T and Hirakata, Y and Watari, T and Yamaguchi, T}, title = {Enrichment of microbial communities for hexavalent chromium removal using a biofilm reactor.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {55}, number = {14}, pages = {1589-1595}, doi = {10.1080/10934529.2020.1826791}, pmid = {32998606}, issn = {1532-4117}, mesh = {Bacteroidetes/drug effects ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Chromium/*analysis ; Firmicutes/drug effects ; Microbiota/*drug effects ; Polyurethanes/chemistry ; Proteobacteria/drug effects ; RNA, Ribosomal, 16S/genetics ; Water Pollutants, Chemical/*analysis ; Water Purification/*methods ; }, abstract = {Given the toxicity and widespread occurrence of hexavalent chromium [Cr(VI)] in aquatic environments, we investigated the feasibility of a down-flow hanging sponge (DHS) biofilm reactor for the enrichment of microbial communities capable of Cr(VI) removal. In the present study, a laboratory-scale DHS reactor fed with a molasses-based medium containing Cr(VI) was operated for 112 days for the investigation. The enrichment of Cr(VI)-removing microbial communities was evaluated based on water quality and prokaryotic community analyses. Once the DHS reactor began to operate, high average volumetric Cr(VI) removal rates of 1.21-1.45 mg L-sponge[-1] h[-1] were confirmed under varying influent Cr(VI) concentrations (approximately 20-40 mg L[-1]). 16S rRNA gene amplicon sequencing analysis suggested the presence of phylogenetically diverse prokaryotic lineages, including phyla that contain well-known Cr(VI)-reducing bacteria (e.g., Bacteroidetes, Firmicutes, and Proteobacteria) in the polyurethane sponge media of the DHS reactor. Therefore, our findings indicate that DHS reactors have great potential for the enrichment of Cr(VI)-removing microbial communities.}, } @article {pmid32996317, year = {2020}, author = {Moore, RE and Craft, KM and Xu, LL and Chambers, SA and Nguyen, JM and Marion, KC and Gaddy, JA and Townsend, SD}, title = {Leveraging Stereoelectronic Effects in Biofilm Eradication: Synthetic β-Amino Human Milk Oligosaccharides Impede Microbial Adhesion As Observed by Scanning Electron Microscopy.}, journal = {The Journal of organic chemistry}, volume = {85}, number = {24}, pages = {16128-16135}, pmid = {32996317}, issn = {1520-6904}, support = {R01 HD090061/HD/NICHD NIH HHS/United States ; R35 GM133602/GM/NIGMS NIH HHS/United States ; UL1 RR024975/RR/NCRR NIH HHS/United States ; UL1 TR000445/TR/NCATS NIH HHS/United States ; }, mesh = {*Biofilms ; Microscopy, Electron, Scanning ; *Milk, Human ; Oligosaccharides/pharmacology ; Staphylococcus aureus ; }, abstract = {Alongside Edward, Lemieux was among the earliest researchers studying negative hyperconjugation (i.e., the anomeric effect) or the preference for gauche conformations about the C1-O5 bond in carbohydrates. Lemieux also studied an esoteric, if not controversial, theory known as the reverse anomeric effect (RAE). This theory is used to rationalize scenarios where predicted anomeric stabilization does not occur. One such example is the Kochetkov amination where reducing end amines exist solely as the β-anomer. Herein, we provide a brief account of Lemieux's contributions to the field of stereoelectronics and apply this knowledge toward the synthesis of β-amino human milk oligosaccharides (βΑ-HMOs). These molecules were evaluated for their ability to inhibit growth and biofilm production in Group B Streptococcus (GBS) and Staphylococcus aureus. While the parent HMOs lacked antimicrobial and antibiofilm activity, their β-amino derivatives significantly inhibited biofilm formation in both species. Field emission gun-scanning single electron microscopy (FEG-SEM) revealed that treatment with β-amino HMOs significantly inhibits bacterial adherence and eliminates the ability of both microbes to form biofilms.}, } @article {pmid32995672, year = {2021}, author = {Tang, M and Chen, C and Zhu, J and Allcock, HR and Siedlecki, CA and Xu, LC}, title = {Inhibition of bacterial adhesion and biofilm formation by a textured fluorinated alkoxyphosphazene surface.}, journal = {Bioactive materials}, volume = {6}, number = {2}, pages = {447-459}, pmid = {32995672}, issn = {2452-199X}, support = {R21 AI139706/AI/NIAID NIH HHS/United States ; }, abstract = {The utilization of biomaterials in implanted blood-contacting medical devices often induces a persistent problem of microbial infection, which results from bacterial adhesion and biofilm formation on the surface of biomaterials. In this research, we developed new fluorinated alkoxyphosphazene materials, specifically poly[bis(octafluoropentoxy) phosphazene] (OFP) and crosslinkable OFP (X-OFP), with improved mechanical properties, and further modified the surface topography with ordered pillars to improve the antibacterial properties. Three X-OFP materials, X-OFP3.3, X-OFP8.1, X-OFP13.6, with different crosslinking densities were synthesized, and textured films with patterns of 500/500/600 nm (diameter/spacing/height) were fabricated via a two stage soft lithography molding process. Experiments with 3 bacterial strains: Staphylococcal epidermidis, Staphylococcal aureus, and Pseudomonas aeruginosa showed that bacterial adhesion coefficients were significantly lower on OFP and X-OFP smooth surfaces than on the polyurethane biomaterial, and surface texturing further reduced bacterial adhesion due to the reduction in accessible surface contact area. Furthermore the anti-bacterial adhesion effect shows a positive relationship with the crosslinking degree. Biofilm formation on the substrates was examined using a CDC biofilm reactor for 7 days and no biofilm formation was observed on textured X-OFP biomaterials. The results suggested that the combination of fluorocarbon chemistry and submicron topography modification in textured X-OFP materials may provide a practical approach to improve the biocompatibility of current biomaterials with significant reduction in risk of pathogenic infection.}, } @article {pmid32995315, year = {2020}, author = {S, LP and A, U and S J, GF}, title = {Investigation on the biofilm eradication potential of selected medicinal plants against methicillin-resistant Staphylococcus aureus.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {28}, number = {}, pages = {e00523}, pmid = {32995315}, issn = {2215-017X}, abstract = {Biofilms are multi-species bacterial communities with complex structures that create antibiotic resistance, cause life-threatening infections, thereby considerable economic loss; needed new approaches. Medicinal plants are focused as new alternatives for their therapeutic and antimicrobial effects. Our present study, Azadirachta indica, Moringa oleifera, Murraya koenigii, and Psidium guajava extracts were investigated against MRSA. The preliminary antimicrobial study showed pet. ether extract of A. indica and ethanolic extract of P. guajava showed a MIC value of 125 μg/mL and MBC value of 500 μg/mL. These extracts showed biofilm inhibition in the range of 60.0-83.9 % and did not possess any hemolytic activity to the human erythrocytes. The plant species investigated in this study had different degrees of antibiofilm activity against MRSA. However, we suggest that A. indica and P. guajava are promising candidates and further investigation is needed to isolate the antimicrobial compounds for the management of MRSA and its mechanism of activity.}, } @article {pmid32994746, year = {2020}, author = {Yang, X and Rajivgandhi, GN and Ramachandran, G and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Almanaa, TN and Manoharan, N and Viji, R}, title = {Preparative HPLC fraction of Hibiscus rosa-sinensis essential oil against biofilm forming Klebsiella pneumoniae.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {10}, pages = {2853-2862}, pmid = {32994746}, issn = {1319-562X}, abstract = {Recent years Klebsiella pneumoniae (K. pneumoniae) biofilm formation (BF) is emerging thread worldwide. For tackling this problem, we have chosen Hibiscus rosa-. pneumoniae. The HPLC purified essential oils (EOs sinensis (H. rosa-sinensis) (HRS) to inhibit the BF K) of H. rosa-sinensis was performed against BF K. pneumoniae and showed concentration dependent biofilm inhibition. At the MBIC of EOs (90 µg/ml), the biofilm inhibition was showed at 92% against selected BF K. Pneumoniae. The biofilm metabolic assay, exopolysaccharide quantification and hydrophobicity index variation results exhibited with 88%, 92% and 89% reduction at 90 μg/mL was observed respectively. In addition, the morphological modification of MBIC treated K. pneumoniae was clearly viewed by scanning electron microscope (SEM). Overall, all the invitro experiments result were confirmed that the MBIC of H. rosa-sinensis EOs was very effective against BF K. pneumonia.}, } @article {pmid32994285, year = {2020}, author = {Trego, AC and O'Sullivan, S and Quince, C and Mills, S and Ijaz, UZ and Collins, G}, title = {Size Shapes the Active Microbiome of Methanogenic Granules, Corroborating a Biofilm Life Cycle.}, journal = {mSystems}, volume = {5}, number = {5}, pages = {}, pmid = {32994285}, issn = {2379-5077}, support = {MR/L015080/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Methanogenic archaea are key players in cycling organic matter in nature but also in engineered waste treatment systems, where they generate methane, which can be used as a renewable energy source. In such systems in the built environment, complex methanogenic consortia are known to aggregate into highly organized, spherical granular biofilms comprising the interdependent microbial trophic groups mediating the successive stages of the anaerobic digestion (AD) process. This study separated methanogenic granules into a range of discrete size fractions, hypothesizing different biofilm growth stages, and separately supplied each with specific substrates to stimulate the activity of key AD trophic groups, including syntrophic acid oxidizers and methanogens. Rates of specific methanogenic activity were measured, and amplicon sequencing of 16S rRNA gene transcripts was used to resolve phylotranscriptomes across the series of size fractions. Increased rates of methane production were observed in each of the size fractions when hydrogen was supplied as the substrate compared with those of volatile fatty acids (acetate, propionate, and butyrate). This was connected to a shift toward hydrogenotrophic methanogenesis dominated by Methanobacterium and Methanolinea Interestingly, the specific active microbiomes measured in this way indicated that size was significantly more important than substrate in driving the structure of the active community in granules. Multivariate integration studywise discriminant analysis identified 56 genera shaping changes in the active community across both substrate and size. Half of those were found to be upregulated in the medium-sized granules, which were also the most active and potentially of the most important size, or life stage, for precision management of AD systems.IMPORTANCE Biological wastewater conversion processes collectively constitute one of the single biggest worldwide applications of microbial communities. There is an obvious requirement, therefore, to study the microbial systems central to the success of such technologies. Methanogenic granules, in particular, are architecturally fascinating biofilms that facilitate highly organized cooperation within the metabolic network of the anaerobic digestion (AD) process and, thus, are especially intriguing model systems for microbial ecology. This study, in a way not previously reported, provoked syntrophic and methanogenic activity and the structure of the microbial community, using specific substrates targeting the key trophic groups in AD. Unexpectedly, granule size more strongly than substrate shaped the active portion of the microbial community. Importantly, the findings suggest the size, or age, of granules inherently shapes the active microbiome linked to a life cycle. This provides exciting insights into the function of, and the potential for additional modeling of biofilm development in, methanogenic granules.}, } @article {pmid32993780, year = {2020}, author = {Horowitz, RI and Murali, K and Gaur, G and Freeman, PR and Sapi, E}, title = {Effect of dapsone alone and in combination with intracellular antibiotics against the biofilm form of B. burgdorferi.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {455}, pmid = {32993780}, issn = {1756-0500}, support = {not known//Global Lyme Alliance/ ; }, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Borrelia burgdorferi ; Dapsone/pharmacology ; Humans ; *Lyme Disease/drug therapy ; }, abstract = {OBJECTIVE: Lyme disease is a tick-borne, multisystemic disease caused by Borrelia burgdorferi. Standard treatments for early Lyme disease include short courses of oral antibiotics but relapses often occur after discontinuation of treatment. Several studies have suggested that ongoing symptoms may be due to a highly antibiotic resistant form of B. burgdorferi called biofilms. Our recent clinical study reported the successful use of an intracellular mycobacterium persister drug used in treating leprosy, diaminodiphenyl sulfone (dapsone), in combination therapy for the treatment of Lyme disease. In this in vitro study, we evaluated the effectiveness of dapsone individually and in combination with cefuroxime and/or other antibiotics with intracellular activity including doxycycline, rifampin, and azithromycin against Borrelia biofilm forms utilizing crystal violet biofilm mass, and dimethyl methylene blue glycosaminoglycan assays combined with Live/Dead fluorescent microscopy analyses.

RESULTS: Dapsone, alone or in various combinations with doxycycline, rifampin and azithromycin produced a significant reduction in the mass and protective glycosaminoglycan layer and overall viability of B. burgdorferi biofilm forms. This in vitro study strongly suggests that dapsone combination therapy could represent a novel and effective treatment option against the biofilm form of B. burgdorferi.}, } @article {pmid32993384, year = {2020}, author = {Souza, JGS and Del Bel Cury, AA and Cury, JA and Tenuta, LMA}, title = {On the release of fluoride from biofilm reservoirs during a cariogenic challenge: an in situ study.}, journal = {Biofouling}, volume = {36}, number = {7}, pages = {870-876}, doi = {10.1080/08927014.2020.1826455}, pmid = {32993384}, issn = {1029-2454}, mesh = {*Biofilms ; Calcium ; *Cariostatic Agents ; *Fluorides/pharmacokinetics ; Hydrogen-Ion Concentration ; Minerals ; Sucrose ; }, abstract = {Biofilm fluoride reservoirs may be a source of fluoride to the fluid phase during a sugar challenge reducing tooth mineral loss. However, the evidence for that is conflicting and has not been studied in biofilms containing different fluoride levels. In order to test fluoride release from biofilms with distinct fluoride concentrations, biofilms were grown in situ exposed to a combination of placebo, calcium and fluoride rinses forming biofilms with no (fluoride-free rinses), low (fluoride-only rinses) or high (calcium followed by fluoride rinses) fluoride concentrations, and collected before and 5 min after a sucrose challenge. Rinsing with fluoride increased fluoride concentration in the biofilm (p < 0.05), mainly when a calcium pre-rinse was used before the fluoride (p < 0.05). However, after a sugar challenge, no significant increase in the biofilm fluid fluoride concentration was observed, even in the fluoride-rich biofilms (p > 0.05). Fluoride-rich biofilms do not release fluoride to the fluid phase during a sugar challenge.}, } @article {pmid32993357, year = {2020}, author = {Faveri, M and Miquelleto, DEC and Bueno-Silva, B and Pingueiro, JMS and Figueiredo, LC and Dolkart, O and Yakobson, E and Barak, S and Feres, M and Shibli, JA}, title = {Antimicrobial effects of a pulsed electromagnetic field: an in vitro polymicrobial periodontal subgingival biofilm model.}, journal = {Biofouling}, volume = {36}, number = {7}, pages = {862-869}, doi = {10.1080/08927014.2020.1825694}, pmid = {32993357}, issn = {1029-2454}, mesh = {*Anti-Infective Agents ; *Bacteroides ; *Biofilms ; Capnocytophaga ; *Electromagnetic Fields ; }, abstract = {The objective was to test the influence of a pulsed electromagnetic field (PEMF) on bacterial biofilm colonization around implants incorporated with healing abutments. Healing abutments with (test group) and without (control group) active PEMF devices were placed in a multispecies biofilm consisting of 31 different bacterial species. The biofilm composition and total bacterial counts (x10[5]) were analyzed by checkerboard DNA-DNA hybridization. After 96 h, the mean level of 7 out of the 31 bacterial species differed significantly between groups, namely Eubacterium nodatum, Fusobacterium nucleatum ssp. nucleatum, Streptococcus intermedius, Streptococcus anginosus, Streptococcus mutans, Fusobacterium nucleatum ssp. Vicentii and Capnocytophaga ochracea were elevated in the control group (p < 0.05). The mean total bacterial counts were lower in the Test group vs the control group (p < 0.05). An electromagnetic healing cap had antimicrobial effects on the bacterial species and can be used to control bacterial colonization around dental implants. Further clinical studies should be conducted to confirm these findings.}, } @article {pmid32993180, year = {2020}, author = {Spałek, J and Deptuła, P and Cieśluk, M and Strzelecka, A and Łysik, D and Mystkowska, J and Daniluk, T and Król, G and Góźdź, S and Bucki, R and Durnaś, B and Okła, S}, title = {Biofilm Growth Causes Damage to Silicone Voice Prostheses in Patients after Surgical Treatment of Locally Advanced Laryngeal Cancer.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {32993180}, issn = {2076-0817}, support = {2018/30/M/NZ6/00502//Narodowe Centrum Nauki/ ; UDA- RPPD.01.01.00-20-001/15-00//Ministerstwo Nauki i Szkolnictwa Wyższego/ ; 024/RID/2018/19//Ministerstwo Nauki i Szkolnictwa Wyższego/ ; WZ/WM-IIB/2/2020//Ministerstwo Nauki i Szkolnictwa Wyższego/ ; }, abstract = {Voice prosthesis implantation with the creation of a tracheoesophageal fistula is the gold standard procedure for voice rehabilitation in patients after a total laryngectomy. All patients implanted with a voice prosthesis (VP) have biofilms of fungi and bacteria grow on their surface. Biofilm colonization is one of the main reasons for VP degradation that can lead to VP dysfunction, which increases the high risk of pneumonia. In a 20-month evaluation period, 129 cases of prostheses after replacement procedures were investigated. Microbiological examination of the biofilms revealed that there were four of the most common fungi species (Candida spp.) and a large variety of bacterial species present. We studied the relationship between the time of proper function of Provox VP, the microorganism composition of the biofilm present on it, and the degradation level of the silicone material. Evaluation of the surface of the removed VP using an atomic force microscope (AFM) has demonstrated that biofilm growth might drastically change the silicone's mechanical properties. Changes in silicone stiffness and thermal properties might contribute to the failure of VP function. Our data can serve in future studies for the development of methods to prevent or inhibit biofilm formation on the VP surface that would translate to an increase in their durability and safety.}, } @article {pmid32993120, year = {2020}, author = {Bujňáková, D and Čuvalová, A and Čížek, M and Humenik, F and Salzet, M and Čížková, D}, title = {Canine Bone Marrow Mesenchymal Stem Cell Conditioned Media Affect Bacterial Growth, Biofilm-Associated Staphylococcus aureus and AHL-Dependent Quorum Sensing.}, journal = {Microorganisms}, volume = {8}, number = {10}, pages = {}, pmid = {32993120}, issn = {2076-2607}, support = {2/0085/18//Vedecká Grantová Agentúra MŠVVaŠ SR a SAV/ ; 15-0613//Agentúra na Podporu Výskumu a Vývoja/ ; 19-0193//Agentúra na Podporu Výskumu a Vývoja/ ; 1/0376/20//Vedecká Grantová Agentúra MŠVVaŠ SR a SAV/ ; }, abstract = {The present study investigated the in vitro antibacterial, antibiofilm and anti-Quorum Sensing (anti-QS) activities of canine bone marrow mesenchymal stem cell-conditioned media (cBM MSC CM) containing all secreted factors <30 K, using a disc diffusion test (DDT), spectrophotometric Crystal Violet Assay (SCVA) and Bioluminescence Assay (BA) with QS-reporter Escherichia coli JM109 pSB1142. The results show a sample-specific bacterial growth inhibition (zones varied between 7-30 mm), statistically significant modulation of biofilm-associated Staphylococcus aureus and Escherichia coli bioluminescence (0.391 ± 0.062 in the positive control to the lowest 0.150 ± 0.096 in the experimental group, cf. 11,714 ± 1362 to 7753 ± 700, given as average values of absorbance A550 ± SD versus average values of relative light units to growth RLU/A550 ± SD). The proteomic analysis performed in our previous experiment revealed the presence of several substances with documented antibacterial, antibiofilm and immunomodulatory properties (namely, apolipoprotein B and D; amyloid-β peptide; cathepsin B; protein S100-A4, galectin 3, CLEC3A, granulin, transferrin). This study highlights that cBM MSC CM may represent an important new approach to managing biofilm-associated and QS signal molecule-dependent bacterial infections. To the best of our knowledge, there is no previous documentation of canine BM MSC CM associated with in vitro antibiofilm and anti-QS activity.}, } @article {pmid32992766, year = {2020}, author = {Melo, LDR and Pinto, G and Oliveira, F and Vilas-Boas, D and Almeida, C and Sillankorva, S and Cerca, N and Azeredo, J}, title = {The Protective Effect of Staphylococcus epidermidis Biofilm Matrix against Phage Predation.}, journal = {Viruses}, volume = {12}, number = {10}, pages = {}, pmid = {32992766}, issn = {1999-4915}, mesh = {Biofilms/*growth & development ; Biomass ; Caudovirales/physiology ; Colony Count, Microbial ; Extracellular Polymeric Substance Matrix/ultrastructure/virology ; Host-Pathogen Interactions ; Staphylococcus Phages/*physiology ; Staphylococcus epidermidis/physiology/*virology ; }, abstract = {Staphylococcus epidermidis is a major causative agent of nosocomial infections, mainly associated with the use of indwelling devices, on which this bacterium forms structures known as biofilms. Due to biofilms' high tolerance to antibiotics, virulent bacteriophages were previously tested as novel therapeutic agents. However, several staphylococcal bacteriophages were shown to be inefficient against biofilms. In this study, the previously characterized S. epidermidis-specific Sepunavirus phiIBB-SEP1 (SEP1), which has a broad spectrum and high activity against planktonic cells, was evaluated concerning its efficacy against S. epidermidis biofilms. The in vitro biofilm killing assays demonstrated a reduced activity of the phage. To understand the underlying factors impairing SEP1 inefficacy against biofilms, this phage was tested against distinct planktonic and biofilm-derived bacterial populations. Interestingly, SEP1 was able to lyse planktonic cells in different physiological states, suggesting that the inefficacy for biofilm control resulted from the biofilm 3D structure and the protective effect of the matrix. To assess the impact of the biofilm architecture on phage predation, SEP1 was tested in disrupted biofilms resulting in a 2 orders-of-magnitude reduction in the number of viable cells after 6 h of infection. The interaction between SEP1 and the biofilm matrix was further assessed by the addition of matrix to phage particles. Results showed that the matrix did not inactivate phages nor affected phage adsorption. Moreover, confocal laser scanning microscopy data demonstrated that phage infected cells were less predominant in the biofilm regions where the matrix was more abundant. Our results provide compelling evidence indicating that the biofilm matrix can work as a barrier, allowing the bacteria to be hindered from phage infection.}, } @article {pmid32991638, year = {2020}, author = {Dos Santos Neto, OM and do Nascimento, C and de Oliveira Silva, TS and Macedo, AP and Ribeiro, RF and Watababe, IS and Mardegan Issa, JP}, title = {Genomic Evaluation of Formed Biofilm on Dental Implants with Different Surface Treatments Associated with Zirconia or Titanium Abutments: An In Vitro Study.}, journal = {The International journal of oral & maxillofacial implants}, volume = {35}, number = {5}, pages = {888-899}, doi = {10.11607/jomi.8239}, pmid = {32991638}, issn = {1942-4434}, mesh = {Biofilms ; Dental Implant-Abutment Design ; *Dental Implants ; Genomics ; Humans ; Materials Testing ; *Titanium ; Zirconium ; }, abstract = {PURPOSE: The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments.

MATERIALS AND METHODS: Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments.

RESULTS: The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P < .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment.

CONCLUSION: Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species.}, } @article {pmid32991256, year = {2021}, author = {Özkul, C and Hazırolan, G}, title = {Oxacillinase Gene Distribution, Antibiotic Resistance, and Their Correlation with Biofilm Formation in Acinetobacter baumannii Bloodstream Isolates.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {5}, pages = {637-646}, doi = {10.1089/mdr.2020.0130}, pmid = {32991256}, issn = {1931-8448}, mesh = {Acinetobacter baumannii/*drug effects/enzymology/genetics ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Colistin/pharmacology ; Drug Resistance, Multiple, Bacterial/genetics ; Genes, Bacterial/*genetics ; Genotype ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; beta-Lactamases/*genetics ; }, abstract = {Objectives: The limitations of treatment options in bloodstream infections caused by multidrug-resistant Acinetobacter baumannii (MDRAB) have been related to high morbidity and mortality. The aim of our present study was to determine antimicrobial susceptibility profiles, molecular resistance patterns, and biofilm properties of A. baumannii isolated from bloodstream infections. Materials and Methods: In the present study, a total of 44 A. baumannii bloodstream isolates were included. Antimicrobial susceptibility profiles and biofilm formation ability were assessed. The distribution of class D carbapenemases, ISAba1, ISAba1/blaOXA-23, blaNDM-1, mcr-1, and ompA was investigated by polymerase chain reaction (PCR). Arbitrarily primed-PCR (AP-PCR) was performed to evaluate clonal relationships. Results: A total of 32 isolates were MDRAB, whereas 6 isolates were also resistant to colistin without mcr-1 positivity. All isolates were harboring blaOXA-51 gene, whereas blaOXA-23 positivity was 63.6%. Fifty percent of the isolates had ISAba1. ISAba1 upstream of blaOXA-23 was determined in 18 isolates. None of the isolates were positive for blaNDM-1 gene. Majority of the strains were strong biofilm producers (86.8%). A total of 56.8% of the isolates were positive for ompA gene with no direct association with strong biofilm formation. However, blaOXA-51 + 23 genotype and trimethoprim-sulfamethoxazole resistance showed a significant relationship with biofilm formation. AP-PCR analysis revealed six distinct clusters of A. baumannii. Conclusions: Herein, majority of the A. baumannii blood isolates were characterized as blaOXA-51+OXA-23 carbapenemase genotype and were strong biofilm formers. None of the isolates were positive for blaNDM-1, which was promising. Resistant isolates were tended to form strong biofilms. Our results highlight the emergence of oxacillinase-producing MDRAB isolated from bloodstream with high biofilm formation ability.}, } @article {pmid32990985, year = {2021}, author = {Pereira, TC and Boutsioukis, C and Dijkstra, RJB and Petridis, X and Versluis, M and de Andrade, FB and van de Meer, WJ and Sharma, PK and van der Sluis, LWM and So, MVR}, title = {Biofilm removal from a simulated isthmus and lateral canal during syringe irrigation at various flow rates: a combined experimental and Computational Fluid Dynamics approach.}, journal = {International endodontic journal}, volume = {54}, number = {3}, pages = {427-438}, pmid = {32990985}, issn = {1365-2591}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Abel Tasman Talent Program/ ; //European Society of Endodontology/ ; //the Abel Tasman Talent Program (ATTP) of the Graduate School of Medical Sciences of the University of Groningen/ ; //CNPq/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Hydrodynamics ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Syringes ; Therapeutic Irrigation ; }, abstract = {AIM: (i) To quantify biofilm removal from a simulated isthmus and a lateral canal in an artificial root canal system during syringe irrigation with NaOCl at different concentrations and delivered at various flow rates (ii) to examine whether biofilm removal is further improved by a final high-flow-rate rinse with an inert irrigant following irrigation with NaOCl. (iii) to simulate the irrigant flow in these areas using a computer model (iv) to examine whether the irrigant velocity calculated by the computer model is correlated to biofilm removal.

METHODOLOGY: Ninety-six artificial root canals with either a simulated isthmus or lateral canal were used. A dual-species in vitro biofilm was formed in these areas using a Constant Depth Film Fermenter. NaOCl at various concentrations (2, 5 and 10%) or adhesion buffer (control) was delivered for 30 s by a syringe and an open-ended needle at 0.033, 0.083, or 0.166 mL s[-1] or passively deposited in the main root canal (phase 1). All specimens were subsequently rinsed for 30 s with adhesion buffer at 0.166 mL s[-1] (phase 2). The biofilm was scanned by Optical Coherence Tomography to determine the percentage of the remaining biofilm. Results were analysed by two 3-way mixed-design ANOVAs (α = 0.05). A Computational Fluid Dynamics model was used to simulate the irrigant flow inside the artificial root canal system.

RESULTS: The flow rate during phase 1 and additional irrigation during phase 2 had a significant effect on the percentage of the remaining biofilm in the isthmus (P = 0.004 and P < 0.001). Additional irrigation during phase 2 also affected the remaining biofilm in the lateral canal significantly (P ≤ 0.007) but only when preceded by irrigation at medium or high flow rate during phase 1. The effect of NaOCl concentration was not significant (P > 0.05). Irrigant velocity in the isthmus and lateral canal increased with increasing flow rate and it was substantially correlated to biofilm removal from those areas.

CONCLUSIONS: The irrigant flow rate affected biofilm removal in vitro more than NaOCl concentration. Irrigant velocity predicted by the computer model corresponded with the pattern of biofilm removal from the simulated isthmus and lateral canal.}, } @article {pmid32990178, year = {2022}, author = {Xiao, J and Chen, M and Huang, M and Wang, M and Huang, J}, title = {Systematic evaluation of PDA/PAM/MAH-modified basalt fibre as biofilm carrier for wastewater treatment.}, journal = {Environmental technology}, volume = {43}, number = {9}, pages = {1328-1339}, doi = {10.1080/09593330.2020.1829085}, pmid = {32990178}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; Silicates ; *Waste Disposal, Fluid/methods ; *Water Purification ; }, abstract = {In this study, three kinds of modified basalt fibre (MBF) were used as biofilm carrier to treat wastewater, mainly for the removal of organic matter and nutrient pollutants, which was evaluated the feasibility of modification by pollutants removal performance. Polydopamine modified basalt fibre (PAD-BF) via the surface coating method were obtained. Polyacrylamide modified basalt fibre (PAM-BF) and maleic anhydride-modified basalt fibre (MAH-BF) via the surface grafting method were prepared. The surface physicochemical properties, biomass attachment capacity and pollutants removal efficiency of MBF were systematically investigated. Electron microscope scanning (SEM) revealed that the surface roughness of BF was obviously improved by modification. Besides, fourier transform infrared (FTIR) suggested that the MBF had more surface-active functional groups. The results of sludge immobilization tests showed that PDA/PAM/MAH-BF had higher bio-affinity than ordinary BF with 1.5∼2.3 times on immobilization ratio of microorganisms (IRM). Furthermore, the performances of PDA/PAM/MAH-BF as biofilm carrier for pollutants were significantly higher than that of ordinary BF group. Among them, the highest removal efficiency of COD in PAD-BF biofilm reactor was 95.29 ± 0.99%, while that of BF group was 86.30 ± 3.09%. PAM-BF group had the best removal effect of nutrients with the removal efficiency of 90.83 ± 7.69% for TP and 91.25 ± 6.43% for TN, respectively, while the removal rate of BF group was only about 70%. The improvement of dissolved oxygen (DO) in the MBF reactors was consistent with the enhancement of contaminant removal. Therefore, PDA/PAM/MAH-BF can be used as promising biological carrier fillers in wastewater treatment engineering.}, } @article {pmid32990175, year = {2020}, author = {Sowndarya, S and Kanmani, S and Raj, SA}, title = {Treatment of high-strength sewage by textile fibers-based sequencing batch biofilm reactor for simultaneous removal of organics and nutrients.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {55}, number = {13}, pages = {1548-1562}, doi = {10.1080/10934529.2020.1826239}, pmid = {32990175}, issn = {1532-4117}, mesh = {Biofilms/growth & development ; Bioreactors/*microbiology ; Denitrification ; Nitrification ; Nitrogen/*analysis ; Phosphorus/*analysis ; Sewage/*chemistry ; *Textiles ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*analysis ; }, abstract = {This study investigates the effectiveness of SBBR with low-cost textile fibers-based bio-carrier namely polypropylene fibers for the treatment of real sewage. The influent loading rates of COD, TN, and TP were averaged at 0.2780, 0.0170, and 0.0077 kg/m[3].d, respectively. The removal efficiencies of BOD, COD, TN, and TP recorded in SBBR were 98%, 93%, 82%, and 44%, respectively at an aeration time of 4 h. The TN and TP removal achieved in SBBR were 2.05 and 2.75 times, respectively higher than SBR. The COD removal efficiency was more than 90% under all SRT conditions (10, 14, 18, 22, and 26 d) in SBBR, and the highest efficiency of 93% was obtained at an SRT of 22 days. As the SRT increased, the nitrogen and phosphorus removal decreased, because the denitrification rate and phosphorus release and uptake rate decreased at longer SRT. Simultaneous nitrification and denitrification (SND) efficiency was 85% in SBBR and 44% in SBR, indicating the co-existence of aerobic nitrifiers and anoxic denitrifiers in the biofilm reactor. In SBBR, the nitrogen mass balance showed 74% of nitrogen removed by denitrification, 9% was removed through sludge wasting process, and 13% was removed in effluent at an SRT of 22 days and DO concentration of 3 mg/L. The t-test results suggest that the performance of SBBR was better than SBR in nitrogen and phosphorus removal at a 95% confidence interval.}, } @article {pmid32988818, year = {2020}, author = {Zhuchenko, G and Schmidt-Malan, S and Patel, R}, title = {Planktonic and Biofilm Activity of Eravacycline against Staphylococci Isolated from Periprosthetic Joint Infections.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {12}, pages = {}, pmid = {32988818}, issn = {1098-6596}, mesh = {*Anti-Bacterial Agents/pharmacology/therapeutic use ; *Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Plankton ; Prostheses and Implants/adverse effects ; *Staphylococcal Infections/drug therapy ; Staphylococcus ; Staphylococcus aureus ; *Tetracyclines/pharmacology ; }, abstract = {MIC and minimum biofilm bactericidal concentration (MBBC) values of eravacycline against 185 staphylococci from periprosthetic joint infections were determined. Staphylococcus aureus had MICs of ≤0.25 μg/ml. MICs for methicillin-susceptible and -resistant Staphylococcus epidermidis were ≤1 and ≤2 μg/ml, respectively. S. aureus and S. epidermidis MBBC50 and MBBC90 values were 8 and 16 μg/ml for each, showing poor anti-staphylococcal biofilm activity using the method studied.}, } @article {pmid32987638, year = {2020}, author = {Rosato, A and Sblano, S and Salvagno, L and Carocci, A and Clodoveo, ML and Corbo, F and Fracchiolla, G}, title = {Anti-Biofilm Inhibitory Synergistic Effects of Combinations of Essential Oils and Antibiotics.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {32987638}, issn = {2079-6382}, abstract = {In recent years, the increase of bacteria antibiotic- resistance has been a severe problem for public health. A useful solution could be to join some phytochemicals naturally present in essential oils (EOs) to the existing antibiotics, with the aim to increase their efficacy in therapies. According to in vitro studies, EOs and their components could show such effects. Among them, we studied the activity of Cinnammonum zeylanicum, Mentha piperita, Origanum vulgare, and Thymus vulgaris EOs on bacterial biofilm and their synergism when used in association with some common antibiotics such as norfloxacin, oxacillin, and gentamicin. The chemical composition of EOs was determined using gas chromatography (GC) coupled with mass spectrometry (MS) techniques. The EOs drug efficacy was evaluated on four different strains of Gram-positive bacteria forming biofilms. The synergistic effects were tested through the chequerboard microdilution method. The association EOs-antibiotics showed a strong destruction of the biofilm growth of the four bacterial species considered. The interaction of norfloxacin with EOs was the most effective in all the tested combinations against the strains object of this study. These preliminary results suggest the formulation of a new generation of antimicrobial agents based on a combination of antimicrobial compounds with different origin.}, } @article {pmid32987169, year = {2020}, author = {Vendramini, Y and Salles, A and Portella, FF and Brew, MC and Steier, L and de Figueiredo, JAP and Bavaresco, CS}, title = {Antimicrobial effect of photodynamic therapy on intracanal biofilm: A systematic review of in vitro studies.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {32}, number = {}, pages = {102025}, doi = {10.1016/j.pdpdt.2020.102025}, pmid = {32987169}, issn = {1873-1597}, mesh = {*Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Humans ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology/therapeutic use ; *Root Canal Therapy ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (A-PDT), is one of the adjunctive therapies developed to improve the effectiveness of root canal disinfection.. The aim of this study was to analyze the antimicrobial effect of PDT on intracanal biofilm.

METHODS: Two reviewers conducted a literature search in PubMed, MEDLINE, Lilacs, SciELO, EMBASE and Google Scholar using the following search strategy: photochemotherapy "[Mesh] OR (photodynamic therapy) AND" dental plaque "[Mesh] OR (dental biofilm) AND (root canal). The following data were collected: publication year, author's name, study site, type of study, participant number, type of photosensitizer, type of laser, method of data collection, application time and results. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS).

RESULTS: After selection based on title, abstract and full text, 27 studies were included in this systematic review. PDT reduced bacterial viability in most studies when combined with conventional endodontic techniques.

CONCLUSION: PDT reduced bacterial counts in most studies, especially when used as an adjunct to the conventional endodontic technique to treat refractory infection. However, PDT effects on in vitro bacterial biofilm were not accurately quantified because of the numerous biases in the studies reviewed.}, } @article {pmid32985275, year = {2020}, author = {Grande, R and Puca, V and Muraro, R}, title = {Antibiotic resistance and bacterial biofilm.}, journal = {Expert opinion on therapeutic patents}, volume = {30}, number = {12}, pages = {897-900}, doi = {10.1080/13543776.2020.1830060}, pmid = {32985275}, issn = {1744-7674}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Drug Resistance, Microbial ; Humans ; Patents as Topic ; }, } @article {pmid32985271, year = {2020}, author = {Carradori, S and Di Giacomo, N and Lobefalo, M and Luisi, G and Campestre, C and Sisto, F}, title = {Biofilm and Quorum Sensing inhibitors: the road so far.}, journal = {Expert opinion on therapeutic patents}, volume = {30}, number = {12}, pages = {917-930}, doi = {10.1080/13543776.2020.1830059}, pmid = {32985271}, issn = {1744-7674}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Drug Development ; Drug Resistance, Bacterial ; Humans ; Patents as Topic ; Quorum Sensing/*drug effects ; Structure-Activity Relationship ; }, abstract = {INTRODUCTION: Biofilm is a complex aggregation of microorganisms characterized by the presence of a dynamic, adhesive and protective extracellular matrix composed of polysaccharides, proteins and nucleic acids. It is estimated that the vast majority of human infections are related to the biofilm in which the microorganisms reside and communicate with each other (Quorum Sensing), surviving in hostile environmental conditions.

AREAS COVERED: This review provides a comprehensive focus on the development state of promising strategies against biofilm production and eradication describing chemical structures, results, administration routes, pharmaceutical compositions, and SARs as well as their shortcomings within the 2019-2020 range.

EXPERT OPINION: New pharmacological targets have been explored in the past years, allowing a broader therapeutic arsenal against biofilm-related pathologies. The Quorum Sensing system was targeted as well in order to avoid the development of intrinsically antibiotic-resistant bacteria and to enhance a proper host defense.}, } @article {pmid32984802, year = {2020}, author = {Bunse, P and Orschler, L and Agrawal, S and Lackner, S}, title = {Membrane aerated biofilm reactors for mainstream partial nitritation/anammox: Experiences using real municipal wastewater.}, journal = {Water research X}, volume = {9}, number = {}, pages = {100066}, pmid = {32984802}, issn = {2589-9147}, abstract = {This study investigated the potential of Membrane-Aerated Biofilm Reactors (MABRs) for mainstream nitrogen removal via partial nitration/anaerobic ammonium oxidation (anammox). Four laboratory-scale MABRs were operated with real municipal wastewater characterized by low concentrations of nitrogen (varying between 31 and 120 mg-NH4-N L[-1]) and the presence of biodegradable organic carbon (soluble COD (sCOD) between 7 and 230 mg-O2 L[-1]). Two reactors were operated with different aeration strategies (intermittent vs. continuous), the other two with differences in biomass retention (recirculation or removal of detached biomass). Keeping a constant HRT caused instabilities due to difficulties with setting the optimal oxygen flux for the respective surface loadings (1.6-6 g-NH4-N m[-2] d[-1]). Operating the MABRs with a constant surface loading (2 g-NH4-N m[-2] d[-1]) resulted in higher and more stable total nitrogen (TN) removal independent of the aeration strategy. The intermittently aerated MABR improved from an average TN removal of 23%-69%, the continuously aerated MABR from 20% to 50% TN removal. Independent of the feeding strategy, the continuously aerated reactor removed slightly more ammonium (80-95%) compared to the intermittently aerated reactor (74-93%). Limiting the oxygen supply by intermittent aeration proofed successful to favor partial nitritation and anammox. Continuous aeration did not achieve stable suppression of nitrite oxidizing bacteria (NOB). Of the removed ammonium, approx. 26% were left in the effluent as nitrate (only 10% with intermittent aeration). Recirculation of the detached biomass resulted in reattachment onto the biofilm or membrane surface. This recirculation led to significantly higher biomass retention times and thus to better performance. Removing detached biofilm from the reactor caused a slightly lower TN removal of 33% compared to 45% with reattachment, while average ammonium removal was 58% compared to 63%, respectively. Scouring events had a significant impact on the overall operation, resulting in short term losses of TN removal capacities of 50-100%. The microbial community composition was different depending on the aeration strategy and biomass retention. The continuously aerated reactor contained significantly more AOB than the intermittently aerated MABR. The reactor with biomass retention contained less ammonium oxidizing bacteria (AOB), compared to the reactor with low biomass retention. In all MABRs, anammox bacteria established in the biofilm after an initial drop in abundance.}, } @article {pmid32983764, year = {2020}, author = {Lee, MA}, title = {Reply: Breast Implant Illness, Biofilm, and the Role of Capsulectomy.}, journal = {Plastic and reconstructive surgery. Global open}, volume = {8}, number = {8}, pages = {e2994}, pmid = {32983764}, issn = {2169-7574}, } @article {pmid32983077, year = {2020}, author = {Hassan, MM and Harrington, NE and Sweeney, E and Harrison, F}, title = {Predicting Antibiotic-Associated Virulence of Pseudomonas aeruginosa Using an ex vivo Lung Biofilm Model.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {568510}, pmid = {32983077}, issn = {1664-302X}, support = {MR/R001898/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {BACKGROUND: Bacterial biofilms are known to have high antibiotic tolerance which directly affects clearance of bacterial infections in people with cystic fibrosis (CF). Current antibiotic susceptibility testing methods are either based on planktonic cells or do not reflect the complexity of biofilms in vivo. Consequently, inaccurate diagnostics affect treatment choice, preventing bacterial clearance and potentially selecting for antibiotic resistance. This leads to prolonged, ineffective treatment.

METHODS: In this study, we use an ex vivo lung biofilm model to study antibiotic tolerance and virulence of Pseudomonas aeruginosa. Sections of pig bronchiole were dissected, prepared and infected with clinical isolates of P. aeruginosa and incubated in artificial sputum media to form biofilms, as previously described. Then, lung-associated biofilms were challenged with antibiotics, at therapeutically relevant concentrations, before their bacterial load and virulence were quantified and detected, respectively.

RESULTS: The results demonstrated minimal effect on the bacterial load with therapeutically relevant concentrations of ciprofloxacin and meropenem, with the latter causing an increased production of proteases and pyocyanin. A combination of meropenem and tobramycin did not show any additional decrease in bacterial load but demonstrated a slight decrease in total proteases and pyocyanin production.

CONCLUSION: In this initial study of six clinical isolates of P. aeruginosa showed high levels of antibiotic tolerance, with minimal effect on bacterial load and increased proteases production, which could negatively affect lung function. Thus, the ex vivo lung model has the potential to be effectively used in larger studies of antibiotic tolerance in in vivo-like biofilms, and show how sub optimal antibiotic treatment of biofilms may potentially contribute to exacerbations and eventual lung failure. We demonstrate a realistic model for understanding antibiotic resistance and tolerance in biofilms clinically and for molecules screening in anti-biofilm drug development.}, } @article {pmid32983061, year = {2020}, author = {Gidari, A and Sabbatini, S and Schiaroli, E and Perito, S and Francisci, D and Baldelli, F and Monari, C}, title = {Tedizolid-Rifampicin Combination Prevents Rifampicin-Resistance on in vitro Model of Staphylococcus aureus Mature Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2085}, pmid = {32983061}, issn = {1664-302X}, abstract = {Staphylococcus aureus infections associated with implanted medical devices are difficult to treat and require long-lasting antibiotic therapies, especially when device removal is not possible or easy such as in the case of joint prostheses. Biofilm formation is a major cause of treatment failure and infection recurrence. This study aimed to test, for the first time, the in vitro combination of tedizolid plus rifampicin on methicillin-sensitive (MSSA ATCC 6538) and methicillin-resistant (MRSA ATCC 43300) S. aureus mature biofilm. Here, we demonstrated that the combination of tedizolid with rifampicin significantly disaggregated pre-formed biofilm of both strains, reduced their metabolic activity and exerted bactericidal activity at clinically meaningful concentrations. Notably, tedizolid was able to completely prevent the emergence of resistance to rifampicin. Moreover these effects were similar to those obtained with daptomycin plus rifampicin, a well-known and widely used combination. Preliminary results on some MRSA clinical isolates confirmed the efficacy of this combination in reducing biofilm biomass and preventing rifampicin resistance onset. Further in vivo studies are needed to confirm the validity of this promising therapeutic option that can be useful against biofilm-associated S. aureus infections.}, } @article {pmid32983053, year = {2020}, author = {Wu, J and Wu, D and Zhao, Y and Si, Y and Mei, L and Shao, J and Wang, T and Yan, G and Wang, C}, title = {Sodium New Houttuyfonate Inhibits Candida albicans Biofilm Formation by Inhibiting the Ras1-cAMP-Efg1 Pathway Revealed by RNA-seq.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2075}, pmid = {32983053}, issn = {1664-302X}, abstract = {Here, we aim to investigate the antifungal effect and mechanism of action of sodium new houttuyfonate (SNH) against Candida albicans. Microdilution analysis results showed that SNH possesses potent inhibitory activity against C. albicans SC5314, with a MIC80 of 256 μg/mL. Furthermore, we found that SNH can effectively inhibit the initial adhesion of C. albicans. Inverted microscopy, crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy results showed that morphological changes during the transition from yeast to hypha and the biofilm formation of C. albicans are repressed by SNH treatment. We also found that SNH can effectively inhibit the biofilm formation of clinical C. albicans strains (Z103, Z3044, Z1402, and Z1407) and SNH in combination with fluconazole, berberine chloride, caspofungin and itraconazole antifungal agents can synergistically inhibit the biofilm formation of C. albicans. Eukaryotic transcriptome sequencing and qRT-PCR results showed that SNH treatment resulted in significantly down-regulated expression in several biofilm formation related genes in the Ras1-cAMP-Efg1 pathway (ALS1, ALA1, ALS3, EAP1, RAS1, EFG1, HWP1, and TEC1) and significantly up-regulated expression in yeast form-associated genes (YWP1 and RHD1). We also found that SNH can effectively reduce the production of key messenger cAMP in the Ras1-cAMP-Efg1 pathway. Furthermore, using Galleria mellonella as an in vivo model we found that SNH can effectively treat C. albicans infection in vivo. Our presented results suggest that SNH exhibits potential antibiofilm effects related to inhibiting the Ras1-cAMP-Efg1 pathway in the biofilm formation of C. albicans.}, } @article {pmid32983050, year = {2020}, author = {Gama, JA and Fredheim, EGA and Cléon, F and Reis, AM and Zilhão, R and Dionisio, F}, title = {Dominance Between Plasmids Determines the Extent of Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2070}, pmid = {32983050}, issn = {1664-302X}, abstract = {Bacterial biofilms have an impact in medical and industrial environments because they often confer protection to bacteria against harmful agents, and constitute a source from which microorganisms can disperse. Conjugative plasmids can enhance bacterial ability to form biofilms because conjugative pili act as adhesion factors. However, plasmids may interact with each other, either facilitating or inhibiting plasmid transfer. Accordingly, we asked whether effects on plasmid transfer also impacts biofilm formation. We measured biofilm formation of Escherichia coli cells harboring two plasmid types, or when the two plasmids were present in the same population but carried in different cells. Using eleven natural isolated conjugative plasmids, we confirmed that some indeed promote biofilm formation and, importantly, that this ability is correlated with conjugative efficiency. Further we studied the effect of plasmid pairs on biofilm formation. We observed increased biofilm formation in approximately half of the combinations when both plasmids inhabited the same cell or when the plasmids were carried in different cells. Moreover, in approximately half of the combinations, independent of the co-inhabitation conditions, one of the plasmids alone determined the extent of biofilm formation - thus having a dominant effect over the other plasmid. The molecular mechanisms responsible for these interactions were not evaluated here and future research is required to elucidate them.}, } @article {pmid32983038, year = {2020}, author = {Fang, JY and Tang, KW and Yang, SH and Alalaiwe, A and Yang, YC and Tseng, CH and Yang, SC}, title = {Synthetic Naphthofuranquinone Derivatives Are Effective in Eliminating Drug-Resistant Candida albicans in Hyphal, Biofilm, and Intracellular Forms: An Application for Skin-Infection Treatment.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {2053}, pmid = {32983038}, issn = {1664-302X}, abstract = {Candida albicans is the most common cause of fungal infection. The emergence of drug resistance leads to the need for novel antifungal agents. We aimed to design naphthofuranquinone analogs to treat drug-resistant C. albicans for topical application on cutaneous candidiasis. The time-killing response, agar diffusion, and live/dead assay of the antifungal activity were estimated against 5-fluorocytosine (5-FC)- or fluconazole-resistant strains. A total of 14 naphthofuranquinones were compared for their antifungal potency. The lead compounds with hydroxyimino (TCH-1140) or O-acetyl oxime (TCH-1142) moieties were the most active agents identified, showing a minimum inhibitory concentration (MIC) of 1.5 and 1.2 μM, respectively. Both compounds were superior to 5-FC and fluconazole for killing planktonic fungi. Naphthofuranquinones efficiently diminished the microbes inside and outside the biofilm. TCH-1140 and TCH-1142 were delivered into C. albicans-infected keratinocytes to eradicate intracellular fungi. The compounds did not reduce the C. albicans burden inside the macrophages, but the naphthofuranquinones promoted the transition of fungi from the virulent hypha form to the yeast form. In the in vivo skin mycosis mouse model, topically applied 5-FC and TCH-1140 reduced the C. albicans load from 1.5 × 10[6] to 5.4 × 10[5] and 1.4 × 10[5] CFU, respectively. The infected abscess diameter was significantly decreased by TCH-1140 (3-4 mm) as compared to the control (8 mm). The disintegrated skin-barrier function induced by the fungi was recovered to the baseline by the compound. The data support the potential of TCH-1140 as a topical agent for treating drug-resistant C. albicans infection without causing skin irritation.}, } @article {pmid32982324, year = {2020}, author = {El-Nagdy, AH and Abdel-Fattah, GM and Emarah, Z}, title = {Detection and Control of Biofilm Formation by Staphylococcus aureus from Febrile Neutropenic Patient.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {3091-3101}, pmid = {32982324}, issn = {1178-6973}, abstract = {INTRODUCTION: Febrile neutropenia (FN) is the evolution of fever in a patient with neutropenia over 38.0°C. Neutropenia is diagnosed when absolute neutrophil count (ANC) <1500 cells/µL. FN represents a common complication of cancer treatment. Hence, it is featured to be a major cause of morbidity and mortality in cancer patients. Staphylococcus aureus is one of the most important microorganisms isolated from the blood of febrile neutropenic patients. Infections caused by S. aureus range from mild to life-threatening diseases. Biofilm production by S. aureus is one of the most significant virulence factors of the bacterium as it prevents the penetration of antibiotics. Recently, it has been shown that S. aureus carries the ica operon responsible for biofilm production. The aim of the work is to determine a genotypic characterization that includes not only the detection of icaA and icaD genes in S. aureus but also the determination of their relation to clinical and microbiological features. Empiric antibacterial treatment was recommended for cancer patients receiving chemotherapy.

MATERIALS AND METHODS: The relation between the presence of icaA and icaD and biofilm production was determined in a collection of 66 S. aureus samples from febrile neutropenic patients. Biofilm-forming ability was tested on Congo Red agar plates. Also, the effect of the most sensitive antibiotics on the bacterial cells was determined by an electron microscope.

RESULTS: Of the bacterial samples, 48 were biofilm-productive and 18 were non-biofilm productive. For the biofilm productive bacteria, 37.5% were positive for icaA, 22.9% were positive for icaD and 10.4% were positive for both. Linezolid was the most effective antibiotic and it is highly recommended for the treatment of febrile neutropenia caused by biofilm-productive S. aureus. Severe changes were found on the bacterial cell after being treated with Linezolid. The icaA and icaD genes were present in only 50% of biofilm-productive bacteria.

CONCLUSION: The ica operon is present in only 50% of biofilm-productive S. aureus and Linezolid is the best antibiotic against these bacteria.}, } @article {pmid32981148, year = {2021}, author = {Kim, HR and Eom, YB}, title = {Antifungal and anti-biofilm effects of 6-shogaol against Candida auris.}, journal = {Journal of applied microbiology}, volume = {130}, number = {4}, pages = {1142-1153}, doi = {10.1111/jam.14870}, pmid = {32981148}, issn = {1365-2672}, support = {NRF-2020R1F1A1071977//National Research Foundation of Korea/ ; SCH-20200618//Soonchunhyang University/ ; }, mesh = {Antifungal Agents/*pharmacology ; Aspartic Acid Proteases/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/physiology ; Catechols/*pharmacology ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {AIMS: This study aimed to assess the antifungal and anti-biofilm effects of 6-shogaol against Candida auris using in vitro phenotypic and genotypic analyses.

METHODS AND RESULTS: Our results showed that 6-shogaol exhibited antifungal as well as anti-biofilm activity by inhibiting biofilm formation and eradicating the preformed biofilms of C. auris. The rate and extent of antifungal activity were further confirmed by a time-kill assay. The XTT reduction assay confirmed that 6-shogaol decreased cellular metabolic activity in the biofilm. The effect of 6-shogaol on established C. auris biofilms was visualized by confocal laser scanning microscopy. Also, this study demonstrated that 6-shogaol reduced the levels of aspartyl proteinases and downregulated the expression of the efflux pump-related CDR1 gene in C. auris.

CONCLUSIONS: The data indicated that 6-shogaol extracted from ginger had antifungal and anti-biofilm effects on C. auris.

This study demonstrated the value of the plant-derived 6-shogaol as a promising and potent bioactive compound. The mode of action of this compound against C. auris biofilm was also proposed.}, } @article {pmid32981012, year = {2020}, author = {Oroh, SB and Mustopa, AZ and Budiarti, S and Budiarto, BR}, title = {Inhibition of enteropathogenic Escherichia coli biofilm formation by DNA aptamer.}, journal = {Molecular biology reports}, volume = {47}, number = {10}, pages = {7567-7573}, doi = {10.1007/s11033-020-05822-8}, pmid = {32981012}, issn = {1573-4978}, mesh = {Aptamers, Nucleotide/*pharmacology ; Biofilms/*drug effects/growth & development ; Enteropathogenic Escherichia coli/isolation & purification/*physiology ; Escherichia coli Infections/drug therapy ; Humans ; }, abstract = {Enteropathogenic Escherichia coli (EPEC) is a bioagent that causes diarrhea through the formation of biofilm. The recalcitrant of EPEC to the current conventional antibiotic treatment has grown a big concern in a way to find effective alternative inhibitors. Aptamers have been demonstrated to show the ability to kill the pathogenic bacteria through inhibition of biofilm formation. Therefore, this study aimed to investigate antibiofilm activities of six types of aptamers against EPEC K1.1 which was isolated from patients with diarrhea. Environmental conditions such as temperatures and pH which impacted on biofilm formation of EPEC K1.1 and also biofilm inhibition of aptamer on EPEC K1.1 were performed by counting the crystal violet formation in 96-well polystyrene microplates at OD570. The motility examination combined with qPCR were applied to prove the mechanism of aptamers inhibition on biofilm by targeting essential genes that involve biofilm formation. The result showed that by applying cut off value at 0.399, aptamer SELEX 10 Colony 5 exhibited the highest biofilm inhibition against EPEC K1.1 with an absorbance value of 0.126. Further analysis showed that this aptamer also was able to reduce the motility diameter of EPEC K1.1. The effect of this aptamer on EPEC K1.1 motility was confirmed by qPCR where the mRNA level of motB, csgA and lsrA gene reduced significantly compared to the untreated group. Aptamer SELEX 10 Colony 5 was able to inhibit biofilm formation through interfering the motility ability of EPEC K1.1 and also by reducing the mRNA level of biofilm formation-related genes. This study provides evidences that aptamer is effective and promising for both antibiofilm of EPEC K1.1 and alternative treatment of diarrhea.}, } @article {pmid32980427, year = {2020}, author = {Xi, Q and Hoth-Hannig, W and Deng, S and Jin, X and Fu, B and Hannig, M}, title = {The effect of polyphenol-containing solutions on in situ biofilm formation on enamel and dentin.}, journal = {Journal of dentistry}, volume = {102}, number = {}, pages = {103482}, doi = {10.1016/j.jdent.2020.103482}, pmid = {32980427}, issn = {1879-176X}, mesh = {Animals ; *Bacterial Adhesion ; Biofilms ; Cattle ; Dental Enamel ; Dentin ; Humans ; *Polyphenols ; }, abstract = {OBJECTIVES: To investigate the effects of Chinese gallnut extracts and pure tannic acid on in situ biofilm formation on enamel and dentin samples over 24 h.

METHODS: Bovine enamel and dentin samples were buccally fixed on maxillary splints. Six volunteers wore the splints for 24 h, and rinsed their mouths with tap water (control), 1% tannic acid- and 1% Chinese gallnut extracts-containing solution twice a day, 3 min after the splints were placed in the mouth and before night sleep. Live/dead staining was used for fluorescence microscopic (FM) visualization and quantification of bacteria viability of biofilms formed on enamel and dentin samples. Biofilm coverage was evaluated and recorded by FM and scanning electron microscopy (SEM). In addition, biofilms were analyzed by transmission electron microscopy (TEM). The Kruskal-Wallis test was used to analyze biofilm data.

RESULTS: Rinsing with tannic acid- and Chinese gallnut extracts-containing solutions significantly reduced in situ biofilm coverage on enamel and dentin samples (P < 0.05). The bacterial viability of biofilms formed on enamel samples was significantly reduced compared to the control (P < 0.05). TEM analysis revealed an increase in pellicle's electron density and thickness and only few or no bacteria adherent to the pellicle in the experimental samples.

CONCLUSIONS: Rinsing with tannic acid- and Chinese gallnut extracts-containing solutions can effectively inhibit in situ biofilm formation, modify the ultrastructure of biofilms on enamel and dentin surfaces and significantly reduce the bacterial viability of biofilm on enamel surfaces.

CLINICAL SIGNIFICANCE: Tannic acid- and Chinese gallnut extracts-containing solutions might be used for dental biofilm management.}, } @article {pmid32979903, year = {2020}, author = {Nath, S and Sinha, A and Singha, YS and Dey, A and Bhattacharjee, N and Deb, B}, title = {Prevalence of antibiotic-resistant, toxic metal-tolerant and biofilm-forming bacteria in hospital surroundings.}, journal = {Environmental analysis, health and toxicology}, volume = {35}, number = {3}, pages = {e2020018}, pmid = {32979903}, issn = {2671-9525}, abstract = {The emergence and rapid spread of antibiotic-resistant bacteria due to unethical and non-scientific disposal of hospital wastes and clinical by-products caused an alarming environmental concern and associated public health risks. The present study aims to assess the co-selection of antibiotic resistance and heavy metal tolerance by bacteria isolated from hospital effluents. These isolates were also tested for hemolytic activity, pH-tolerance, thermal inactivation, auto-aggregation, cell-surface hydrophobicity and interaction with other bacteria. The study reports the prevalence of antibiotic-resistant and heavy metal tolerant bacteria in clinical effluents and water samples. Most of these isolates were resistant to vancomycin, clindamycin, ampicillin, rifampicin, penicillin-G, methicillin and cefdinir, and evidenced the production of extended-spectrum β-lactamase enzyme. Toxic metals such as cadmium, copper, iron, lead and zinc also exert a selection pressure towards antibiotic resistance. Pseudomonas aeruginosa strain GCC_19W3, Bacillus sp. strain GCC_19S2 and Achromobacter spanius strain GCC_SB1 showed β-hemolysis, evidenced by the complete breakdown of the red blood cells. Highest auto-aggregation was exhibited by Bacillus sp. strain GCC_19S2; whereas, maximum cell-surface hydrophobicity was displayed by P. aeruginosa strain GCC_19W1. Antagonistic activity by Stenotrophomonas maltophilia strain GCC_19W2, P. aeruginosa strain GCC_19W3 and strains of Achromobacter restricts the growth of other microorganisms by producing some bactericidal substances. The study emphasises undertaking safety measures for the disposal of clinical effluents directly into the environment. The study suggests adopting necessary measures and regulations to restrict the spread of emerging pathogens within the hospital biome and community, which if unnoticed, might pose a significant clinical challenge.}, } @article {pmid32979797, year = {2020}, author = {Yasmeen, T and Ahmad, A and Arif, MS and Mubin, M and Rehman, K and Shahzad, SM and Iqbal, S and Rizwan, M and Ali, S and Alyemeni, MN and Wijaya, L}, title = {Biofilm forming rhizobacteria enhance growth and salt tolerance in sunflower plants by stimulating antioxidant enzymes activity.}, journal = {Plant physiology and biochemistry : PPB}, volume = {156}, number = {}, pages = {242-256}, doi = {10.1016/j.plaphy.2020.09.016}, pmid = {32979797}, issn = {1873-2690}, mesh = {Antioxidants/*metabolism ; Biofilms ; Helianthus/*microbiology/*physiology ; Plant Roots ; Rhizobiaceae/*physiology ; *Salt Tolerance ; Soil Microbiology ; }, abstract = {Salinity stress is one of the major environmental stresses that impose global socio-economic impacts, as well as hindering crop productivity. Halotolerant plant growth-promoting rhizobacteria (PGPR) having potential to cope with salinity stress can be employed to counter this issue in eco-friendly way. In the present investigation, halotolerant PGPR strains, AP6 and PB5, were isolated from saline soil and characterized for their biochemical, molecular and physiological traits. Sequencing of 16 S rRNA gene and comparative analysis confirmed the taxonomic affiliation of AP6 with Bacillus licheniformis and PB5 with Pseudomonas plecoglossicida. The study was carried out in pots with different levels of induced soil salinity viz. 0, 5, 10 and 15 dSm[-1] to evaluate the potential of bacterial inoculants in counteracting salinity stress in sunflower at different plant growth stages (30, 45 and 60 days after sowing). Both the bacterial inoculants were capable of producing indole acetic acid and biofilm, solubilizing inorganic rock phosphate, and also expressed ACC deaminase activity. The PGPR inoculated plants showed significantly higher fresh and dry biomass, plant height, root length and yield plant[-1]. Ameliorative significance of applied bacterial inoculants was also evidenced by mitigating oxidative stress through upregulation of catalase (CAT), superoxide dismutase (SOD) and guaiacol peroxidase (GPX) antioxidant enzymes. Increase in photosynthetic pigments, gas exchange activities and nutrient uptake are crucial salt stress adaptations, which were enhanced with the inoculation of salt tolerant biofilm producing PGPR in sunflower plants. Although increase in salinity stress levels has gradually decreased the plant's output compared to non-salinized plants, the plants inoculated with PGPR confronted salinity stress in much better way than uninoculated plants. Owing to the wide action spectrum of these bacterial inoculants, it was concluded that these biofilm PGPR could serve as effective bioinoculants and salinity stress alleviator for sunflower (oil seed crop) by increasing crop productivity in marginalized agricultural systems.}, } @article {pmid32979637, year = {2021}, author = {Vyas, N and Wang, QX and Walmsley, AD}, title = {Improved biofilm removal using cavitation from a dental ultrasonic scaler vibrating in carbonated water.}, journal = {Ultrasonics sonochemistry}, volume = {70}, number = {}, pages = {105338}, pmid = {32979637}, issn = {1873-2828}, mesh = {*Biofilms ; *Carbonated Water ; *Dental Instruments ; Sonication/*methods ; }, abstract = {The use of cavitation for improving biofilm cleaning is of great interest. There is no system at present that removes the biofilm from medical implants effectively and specifically from dental implants. Cavitation generated by a vibrating dental ultrasonic scaler tip can clean biomaterials such as dental implants. However, the cleaning process must be significantly accelerated for clinical applications. In this study we investigated whether the cavitation could be increased, by operating the scaler in carbonated water with different CO2 concentrations. The cavitation around an ultrasonic scaler tip was recorded with high speed imaging. Image analysis was used to calculate the area of cavitation. Bacterial biofilm was grown on surfaces and its removal was imaged with a high speed camera using the ultrasonic scaler in still and carbonated water. Cavitation increases significantly with increasing carbonation. Cavitation also started earlier around the tips when they were in carbonated water compared to non-carbonated water. Significantly more biofilm was removed when the scaler was operated in carbonated water. Our results suggest that using carbonated water could significantly increase and accelerate cavitation around ultrasonic scalers in a clinical situation and thus improve biofilm removal from dental implants and other biomaterials.}, } @article {pmid32978132, year = {2020}, author = {Jellison, K and Cannistraci, D and Fortunato, J and McLeod, C}, title = {Biofilm Sampling for Detection of Cryptosporidium Oocysts in a Southeastern Pennsylvania Watershed.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {23}, pages = {}, pmid = {32978132}, issn = {1098-5336}, mesh = {*Biofilms ; Cryptosporidium/*isolation & purification/physiology ; Drinking Water/parasitology ; Fresh Water/*parasitology ; Oocysts/isolation & purification ; Pennsylvania ; Water Supply ; }, abstract = {This study investigated the use of biofilms to monitor Cryptosporidium in water. Benthic rock and submersible slide biofilms were sampled upstream and downstream of point sources in a suburban watershed in southeastern Pennsylvania. More oocysts were detected in biofilms scraped from rocks downstream than upstream of a wastewater treatment plant (WWTP) (19 versus 5, respectively; n = 1). Although not statistically significant, Cryptosporidium oocysts were detected more frequently, and in greater numbers, in biofilms grown on slides downstream than upstream of this same WWTP (83.3% positive samples [n = 12] versus 45.5% positive samples [n = 11], respectively; P = 0.0567). Similarly, Cryptosporidium oocysts were detected more frequently, and in greater numbers, in rock biofilms collected downstream than upstream of a stormwater outfall impacted by defective sewer laterals (50% positive samples downstream and 17% positive samples upstream; n = 6; P = 0.2207). While oocyst detection data obtained by slide biofilms versus filters did not necessarily agree on a given day, there was no seasonal difference in the frequency of oocyst detection (P > 0.05) or numbers of oocysts detected (P > 0.05) whether the water was monitored by filtration or slide biofilm sampling. Within any given season, there was no difference in the frequency of oocyst detection (P > 0.05) or the numbers of oocysts detected (P > 0.05) whether the water was monitored by filtration or slide biofilm sampling. These data show that oocyst detection in biofilms is comparable to oocyst detection in filtered water samples. Biofilm sampling offers significant cost savings compared to the filtration-based EPA Method 1623.1 and could be used to identify watershed locations at potential risk for increased oocyst loads.IMPORTANCE Monitoring Cryptosporidium occurrence in watersheds that provide drinking water is necessary to determine where limited resources should most effectively be directed to protect consumers from waterborne exposure to pathogenic oocysts. Biofilms are a useful tool to monitor complex watersheds and identify point sources of Cryptosporidium oocyst contamination that need to be managed to protect public health. Compared to EPA Method 1623.1, the cost benefit of using biofilms to monitor for Cryptosporidium contamination will enable utilities to sample water supplies more frequently, and at more locations, than is currently possible given limited operating budgets. Biofilm sampling could be used to identify high-risk regions within a large, complex watershed and the associated water treatment plants at potential risk for increased oocyst loads in the water supply; this information could then be used to select the locations within the watershed where the more expensive EPA Method 1623.1 is warranted.}, } @article {pmid32977091, year = {2021}, author = {Lou, Z and Song, Y and Shao, B and Hu, J and Wang, J and Yu, J}, title = {Pre-electrochemical treatment combined with fixed bed biofilm reactor for pyridine wastewater treatment: From performance to microbial community analysis.}, journal = {Bioresource technology}, volume = {319}, number = {}, pages = {124110}, doi = {10.1016/j.biortech.2020.124110}, pmid = {32977091}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; Pyridines ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {To overcome the high biotoxicity and poor biodegradability of pyridine and its derivatives, a pre-electrochemical treatment combined with fixed bed biofilm reactor (EC-FBBR) was designed for multi-component stream including pyridine (Pyr), 3-cyanopyridine (3-CNPyr), and 3-chloropyridine (3-ClPyr). The EC-FBBR system could simultaneously degrade these pollutants with a mineralization efficiency of 90%, especially for the persistent 3-ClPyr. Specifically, the EC could partially degrade all pollutants, and allow them to be completely destructed in FBBR. With EC off, Rhodococcus (35.5%) became the most abundant genus in biofilm, probably due to its high tolerance to 3-ClPyr. With EC on, 3-ClPyr was reduced to an acceptable level, thus Paracoccus (21.1%) outcompeted among interspecies competition with Rhodococcus and became the dominant genus. Paracoccus was considered to participate in the subsequent degradation for the residual 3-ClPyr, and led to the complete destruction for all pollutants. This study proposed promising combination for effective treatment of multi-component pyridine wastewater.}, } @article {pmid32976967, year = {2020}, author = {Xu, D and Zhang, Y and Cheng, P and Wang, Y and Li, X and Wang, Z and Yi, H and Chen, H}, title = {Inhibitory effect of a novel chicken-derived anti-biofilm peptide on P. aeruginosa biofilms and virulence factors.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104514}, doi = {10.1016/j.micpath.2020.104514}, pmid = {32976967}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Chickens ; Microbial Sensitivity Tests ; Peptides ; *Pseudomonas aeruginosa ; Virulence Factors ; }, abstract = {The antibiotic resistance of Pseudomonas aeruginosa (P. aeruginosa) is correlated with the formation of biofilms. Several studies have focused on biofilms and the treatment of biofilm infection by antimicrobial peptides (AMPs). The present study analyzed the feasibility of cCATH-2 (a chicken-derived antimicrobial peptide) as a new strategy for anti-biofilm activities. Biofilm biomass (crystal violet staining) and viability of biofilm bacteria (colony counting) were measured in P. aeruginosa PAO1 biofilm at the stage of attachment (4 h), formation (14 h), and maturation (24 h). cCATH-2 (1/2MIC) had the ability to reduce the initial attachment of viable bacteria due to decreasing planktonic bacteria. All tested concentrations of cCATH-2 (1/32-1/2MIC) significantly reduced the biomass at the biofilm formation stage. In addition, cCATH-2 (2MIC) had significant effects on the biomass and viability of bacteria of pre-biofilms, which caused significant killing (>90%) of the bacteria in the biofilm. Thus, it was confirmed that cCATH-2 could infiltrate into pre-biofilm to kill the biofilm cells, as assessed by confocal laser scanning microscopy (CLSM). Furthermore, cCATH-2 had an obvious effect on the production of the majority of the virulence factors of PAO1 biofilms, and the effect was better than that of ciprofloxacin, especially on alginate (the structural component of biofilms). These findings suggested that cCATH-2 is a putative candidate for the development of anti-biofilm and anti-infective drugs.}, } @article {pmid32976081, year = {2022}, author = {Hu, Y and Hu, Y and Li, Y and Hui, M and Lu, Z and Li, H and Tian, H}, title = {Metagenomic insights into quorum sensing in membrane-aerated biofilm reactors for phenolic wastewater treatment.}, journal = {Environmental technology}, volume = {43}, number = {9}, pages = {1318-1327}, doi = {10.1080/09593330.2020.1829084}, pmid = {32976081}, issn = {1479-487X}, mesh = {Acyl-Butyrolactones ; Biofilms ; Metagenome ; *Quorum Sensing ; *Water Purification ; }, abstract = {Quorum sensing (QS) is of crucial importance for the formation and performance of biofilms adhered to aerated membranes. In this study, the QS-related genes in membrane-aerated biofilm reactors (MABR) for phenolic wastewater treatment were investigated through high-throughput metagenomic sequencing. Results showed that numerous regulatory QS-related genes were associated with the production of signals including acyl-homoserine lactones (AHLs) and diguanylate monophosphate (c-di-GMP), indicating that the biofilms were potentially regulated by the AHL-mediated QS and c-di-GMP-mediated QS systems. Species and functional contribution analysis demonstrated that Pseudomonas, Achromobacter, Rhodococcus, Granulicoccus and Thauera were the key QS-related gene carriers. Redundancy analysis and Spearman correlation analysis showed that high influent phenolic loading gave rise to a high relative abundance of QS bacteria within the biofilm community. Thus, QS-related genes likely play an important role in strengthening biofilm resistance to phenolics, as well as the removal of phenolic contaminants.}, } @article {pmid32975770, year = {2021}, author = {Gray, JA and Chandry, PS and Bowman, JP and Fox, EM}, title = {High-Throughput Screening of Biofilm Formation of Listeria monocytogenes on Stainless Steel Coupons Using a 96-Well Plate Format.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2220}, number = {}, pages = {115-122}, doi = {10.1007/978-1-0716-0982-8_9}, pmid = {32975770}, issn = {1940-6029}, mesh = {*Bacterial Adhesion ; *Biofilms ; Colony Count, Microbial ; *Food Microbiology ; Humans ; Listeria monocytogenes/*physiology ; Listeriosis/microbiology ; *Stainless Steel/analysis ; }, abstract = {Listeria monocytogenes is a foodborne pathogen capable of colonizing and persisting in the food production environment (FPE). While there are a variety of factors involved in L. monocytogenes' ability to persist in FPE, the ability to form biofilms has the potential to increase their chance of survival and long-term colonization. Understanding the mechanisms involved in L. monocytogenes ability to form biofilms may potentially help food safety managers optimize control strategies targeting it in the FPE. In this chapter, a high-throughput method to determine L. monocytogenes ability to attach and form biofilms utilizing FPE-grade stainless steel is described. This method provides fast and efficient results, facilitating scaling up to large numbers of isolates to measure their ability to form biofilms, where lower-throughput approaches can then be utilized to further characterize isolates of interest.}, } @article {pmid32975125, year = {2021}, author = {Silva, DF and Cordeiro, LV and Figueiredo, PTR and Diniz-Neto, H and Souza, HDDS and Lima, EO}, title = {The impact that β-citronellol isomers have on the biofilm formation of Candida yeasts.}, journal = {Natural product research}, volume = {35}, number = {24}, pages = {6002-6006}, doi = {10.1080/14786419.2020.1813131}, pmid = {32975125}, issn = {1478-6427}, mesh = {Acyclic Monoterpenes ; *Antifungal Agents/pharmacology ; Biofilms ; *Candida ; Candida albicans ; Microbial Sensitivity Tests ; }, abstract = {Infections associated with biofilms developed by Candida spp. are becoming a great problem due to its resistance against the immune response of the host and the action of antifungal agents. Hence, finding substances that can inhibit the development of biofilms increases the likelihood that these compounds one day can become good antifungals applied in the clinic. The aim of this study was to evaluate the effect of β-citronellol enantiomers on the biofilm formation by Candida albicans and Candida tropicalis isolated from bloodstream infections. Inhibition was evaluated by reading microplates treated with different concentrations of R-(+)-β-citronellol, S-(-)-β-citronellol and amphotericin B, compared to negative control, in spectrophotometer at 590 nm. All tested concentrations of β-citronellol enantiomers inhibited the biofilm formation of Candida. However, it is still necessary to evaluate the behavior of these isomers on mature biofilms, so that they can become more viable as antifungal therapeutical agents.}, } @article {pmid32974586, year = {2020}, author = {Fredendall, RJ and Stone, JL and Pehl, MJ and Orwin, PM}, title = {Transcriptome profiling of Variovorax paradoxus EPS under different growth conditions reveals regulatory and structural novelty in biofilm formation.}, journal = {Access microbiology}, volume = {2}, number = {6}, pages = {acmi000121}, pmid = {32974586}, issn = {2516-8290}, abstract = {We used transcriptome analysis by paired-end strand-specific RNA-seq to evaluate the specific changes in gene expression associated with the transition to static biofilm growth in the rhizosphere plant growth-promoting bacterium Variovorax paradoxus EPS. Triplicate biological samples of exponential growth, stationary phase and static biofilm samples were examined. DESeq2 and Rockhopper were used to identify robust and widespread shifts in gene expression specific to each growth phase. We identified 1711 protein-coding genes (28%) using DESeq2 that had altered expression greater than twofold specifically in biofilms compared to exponential growth. Fewer genes were specifically differentially expressed in stationary-phase culture (757, 12%). A small set of genes (103/6020) were differentially expressed in opposing fashions in biofilm and stationary phase, indicating potentially substantial shifts in phenotype. Gene-ontology analysis showed that the only class of genes specifically upregulated in biofilms was associated with nutrient transport, highlighting the importance of nutrient uptake in the biofilm. The biofilm-specific genes did not overlap substantially with the loci identified by mutagenesis studies, although some were present in both sets. The most highly upregulated biofilm-specific gene is predicted to be a part of the RNA degradosome, which indicates that RNA stability is used to regulate the biofilm phenotype. Two small putative proteins, Varpa_0407 and Varpa_3832, are highly expressed specifically in biofilms and are predicted to be secreted DNA-binding proteins, which may stabilize extracellular DNA as a component of the biofilm matrix. An flp/tad type-IV pilus locus (Varpa_5148-60) is strongly downregulated specifically in biofilms, in contrast with results from other systems for these pili. Mutagenesis confirms that this locus is important in surface motility rather than biofilm formation. These experimental results suggest that V. paradoxus EPS biofilms have substantial regulatory and structural novelty.}, } @article {pmid32974378, year = {2020}, author = {Pettersson, S and Ahnoff, M and Edin, F and Lingström, P and Simark Mattsson, C and Andersson-Hall, U}, title = {Corrigendum: A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and a Reduced Drop in Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks.}, journal = {Frontiers in nutrition}, volume = {7}, number = {}, pages = {128}, doi = {10.3389/fnut.2020.00128}, pmid = {32974378}, issn = {2296-861X}, abstract = {[This corrects the article on p. 88 in vol. 7, PMID: 32596251.].}, } @article {pmid32974104, year = {2020}, author = {Rosca, AS and Castro, J and Cerca, N}, title = {Evaluation of different culture media to support in vitro growth and biofilm formation of bacterial vaginosis-associated anaerobes.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e9917}, pmid = {32974104}, issn = {2167-8359}, support = {R01 AI146065/AI/NIAID NIH HHS/United States ; }, abstract = {BACKGROUND: Bacterial vaginosis (BV) is one of the most common vaginal infections worldwide. It is associated with the presence of a dense polymicrobial biofilm on the vaginal epithelium, formed mainly by Gardnerella species. The biofilm also contains other anaerobic species, but little is known about their role in BV development.

AIM: To evaluate the influence of different culture media on the planktonic and biofilm growth of six cultivable anaerobes frequently associated with BV, namely Gardnerella sp., Atopobium vaginae, Lactobacillus iners, Mobiluncus curtisii, Peptostreptococcus anaerobius and Prevotella bivia.

METHODS: A total of nine different culture media compositions, including commercially available and chemically defined media simulating genital tract secretions, were tested in this study. Planktonic cultures and biofilms were grown under anaerobic conditions (10% carbon dioxide, 10% helium and 80% nitrogen). Planktonic growth was assessed by optical density measurements, and biofilm formation was quantified by crystal violet staining.

RESULTS: Significant planktonic growth was observed for Gardnerella sp., A. vaginae and L. iners in New York City III broth, with or without ascorbic acid supplementation. Biofilm quantification showed high in vitro biofilm growth for Gardnerella sp., P. anaerobius and P. bivia in almost all culture media excluding Brucella broth. Contrary, only New York City III broth was able to promote biofilm formation for A. vaginae, L. iners and M. curtisii.

CONCLUSIONS: Our data demonstrate that New York City III broth relative to the other tested media is the most conducive for future studies addressing polymicrobial biofilms development as this culture medium allowed the formation of significant levels of single-species biofilms.}, } @article {pmid32973923, year = {2020}, author = {Guo, Y and Wang, G and Zhang, H and Wen, H and Li, W}, title = {Effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs.}, journal = {Biotechnology for biofuels}, volume = {13}, number = {}, pages = {162}, pmid = {32973923}, issn = {1754-6834}, abstract = {BACKGROUND: Extracellular electron transfer (EET) is essential in improving the power generation performance of electrochemically active bacteria (EAB) in microbial fuel cells (MFCs). Currently, the EET mechanisms of dissimilatory metal-reducing (DMR) model bacteria Shewanella oneidensis and Geobacter sulfurreducens have been thoroughly studied. Klebsiella has also been proved to be an EAB capable of EET, but the EET mechanism has not been perfected. This study investigated the effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs.

RESULTS: Herein, we covered the anode of MFC with a layer of microfiltration membrane to block the effect of the biofilm mechanism, and then explore the EET of the electron mediator mechanism of K. quasipneumoniae sp. 203 and electricity generation performance. In the absence of short-range electron transfer, we found that K. quasipneumoniae sp. 203 can still produce a certain power generation performance, and coated-MFC reached 40.26 mW/m[2] at a current density of 770.9 mA/m[2,] whereas the uncoated-MFC reached 90.69 mW/m[2] at a current density of 1224.49 mA/m[2]. The difference in the electricity generation performance between coated-MFC and uncoated-MFC was probably due to the microfiltration membrane covered in anode, which inhibited the growth of EAB on the anode. Therefore, we speculated that K. quasipneumoniae sp. 203 can also perform EET through the biofilm mechanism. The protein content, the integrity of biofilm and the biofilm activity all proved that the difference in the electricity generation performance between coated-MFC and uncoated-MFC was due to the extremely little biomass of the anode biofilm. To further verify the effect of electron mediators on electricity generation performance of MFCs, 10 µM 2,6-DTBBQ, 2,6-DTBHQ and DHNA were added to coated-MFC and uncoated-MFC. Combining the time-voltage curve and CV curve, we found that 2,6-DTBBQ and 2,6-DTBHQ had high electrocatalytic activity toward the redox reaction of K. quasipneumoniae sp. 203-inoculated MFCs. It was also speculated that K. quasipneumoniae sp. 203 produced 2,6-DTBHQ and 2,6-DTBBQ.

CONCLUSIONS: To the best of our knowledge, the three modes of EET did not exist separately. K. quasipneumoniae sp.203 will adopt the corresponding electron transfer mode or multiple ways to realize EET according to the living environment to improve electricity generation performance.}, } @article {pmid32972419, year = {2020}, author = {Pérez-Granda, MJ and Alonso, B and Zavala, R and Latorre, MC and Hortal, J and Samaniego, R and Bouza, E and Muñoz, P and Guembe, M}, title = {Selective digestive decontamination solution used as "lock therapy" prevents and eradicates bacterial biofilm in an in vitro bench-top model.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {19}, number = {1}, pages = {44}, pmid = {32972419}, issn = {1476-0711}, support = {PEJ15/BIO/AI-0406//Consejería de Educación, Juventud y Deporte, Comunidad de Madrid/ ; CP13/000268//Instituto de Salud Carlos III/ ; PI18/00045//Instituto de Salud Carlos III/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; Decontamination/*methods ; Equipment Contamination/prevention & control ; Escherichia coli/*drug effects/physiology ; Humans ; Intubation, Intratracheal/instrumentation ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Pneumonia, Ventilator-Associated/prevention & control ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {BACKGROUND: Most preventing measures for reducing ventilator-associated pneumonia (VAP) are based mainly on the decolonization of the internal surface of the endotracheal tubes (ETTs). However, it has been demonstrated that bacterial biofilm can also be formed on the external surface of ETTs. Our objective was to test in vitro the efficacy of selective digestive decontamination solution (SDDs) onto ETT to prevent biofilm formation and eradicate preformed biofilms of three different microorganisms of VAP.

METHODS: We used an in vitro model in which we applied, at the subglottic space of ETT, biofilms of either P. aeruginosa ATCC 15442, or E. coli ATCC 25922, or S. aureus ATCC 29213, and the SDDs at the same time (prophylaxis) or after 72 h of biofilm forming (treatment). ETT were incubated during 5 days with a regimen of 2 h-locks. ETT fragments were analyzed by sonication and confocal laser scanning microscopy to calculate the percentage reduction of cfu and viable cells, respectively.

RESULTS: Median (IQR) percentage reduction of live cells and cfu/ml counts after treatment were, respectively, 53.2% (39.4%-64.1%) and 100% (100%-100.0%) for P. aeruginosa, and 67.9% (46.7%-78.7%) and 100% (100%-100.0%) for E. coli. S. aureus presented a complete eradication by both methods. After prophylaxis, there were absence of live cells and cfu/ml counts for all microorganisms.

CONCLUSIONS: SDDs used as "lock therapy" in the subglottic space is a promising prophylactic approach that could be used in combination with the oro-digestive decontamination procedure in the prevention of VAP.}, } @article {pmid32971800, year = {2020}, author = {Cepas, V and Ballén, V and Gabasa, Y and Ramírez, M and López, Y and Soto, SM}, title = {Transposon Insertion in the purL Gene Induces Biofilm Depletion in Escherichia coli ATCC 25922.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32971800}, issn = {2076-0817}, support = {634588//European Commission/ ; REIPI RD16/0016/0010//Instituto de Salud Carlos III/ ; PI19/00478//Instituto de Salud Carlos III/ ; }, abstract = {Current Escherichia coli antibiofilm treatments comprise a combination of antibiotics commonly used against planktonic cells, leading to treatment failure. A better understanding of the genes involved in biofilm formation could facilitate the development of efficient and specific new antibiofilm treatments. A total of 2578 E. coli mutants were generated by transposon insertion, of which 536 were analysed in this study. After sequencing, Tn263 mutant, classified as low biofilm-former (LF) compared to the wild-type (wt) strain (ATCC 25922), showed an interruption in the purL gene, involved in the de novo purine biosynthesis pathway. To elucidate the role of purL in biofilm formation, a knockout was generated showing reduced production of curli fibres, leading to an impaired biofilm formation. These conditions were restored by complementation of the strain or addition of exogenous inosine. Proteomic and transcriptional analyses were performed to characterise the differences caused by purL alterations. Thirteen proteins were altered compared to wt. The corresponding genes were analysed by qRT-PCR not only in the Tn263 and wt, but also in clinical strains with different biofilm activity. Overall, this study suggests that purL is essential for biofilm formation in E. coli and can be considered as a potential antibiofilm target.}, } @article {pmid32971787, year = {2020}, author = {Shang, F and Wang, H and Xue, T}, title = {Anti-Biofilm Effect of Tea Saponin on a Streptococcus agalactiae Strain Isolated from Bovine Mastitis.}, journal = {Animals : an open access journal from MDPI}, volume = {10}, number = {9}, pages = {}, pmid = {32971787}, issn = {2076-2615}, support = {31672571//National Natural Science Foundation of China/ ; }, abstract = {Streptococcus agalactiae (GBS) is a highly contagious pathogen which not only can cause neonatal meningitis, pneumonia, and septicemia but is also considered to be a major cause of bovine mastitis (BM), leading to large economic losses to the dairy industry worldwide. Like many other pathogenic bacteria, GBS also has the capacity to form a biofilm structure in the host to cause persistent infection. Tea saponin (TS), is one of the main active agents extracted from tea ash powder, and it has good antioxidant and antibacterial activities. In this study, we confirmed that TS has a slight antibacterial activity against a Streptococcus agalactiae strain isolated from dairy cow with mastitis and inhibits its biofilm formation. By performing scanning electron microscopy (SEM) experiments, we observed that with addition of TS, the biofilm formed by this GBS strain exhibited looser structure and lower density. In addition, the results of real-time reverse transcription polymerase chain reaction (RT-PCR) experiments showed that TS inhibited biofilm formation by down-regulating the transcription of the biofilm-associated genes including srtA, fbsC, neuA, and cpsE.}, } @article {pmid32971750, year = {2020}, author = {Lauková, A and Pogány Simonová, M and Focková, V and Kološta, M and Tomáška, M and Dvorožňáková, E}, title = {Susceptibility to Bacteriocins in Biofilm-Forming, Variable Staphylococci Isolated from Local Slovak Ewes' Milk Lump Cheeses.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32971750}, issn = {2304-8158}, support = {SK-PT-18-0005//Laukova/ ; }, abstract = {Seventeen staphylococci isolated from 54 Slovak local lump cheeses made from ewes' milk were taxonomically allotted to five species and three clusters/groups involving the following species: Staphylococcus aureus (5 strains), Staphylococcus xylosus (3 strains), Staphylococcus equorum (one strain) Staphylococcus succinus (5 strains) and Staphylococcus simulans (3 strains). Five different species were determined. The aim of the study follows two lines: basic research in connection with staphylococci, and further possible application of the bacteriocins. Identified staphylococci were mostly susceptible to antibiotics (10 out of 14 antibiotics). Strains showed γ-hemolysis (meaning they did not form hemolysis) except for S. aureus SAOS1/1 strain, which formed β-hemolysis. S. aureus SAOS1/1 strain was also DNase positive as did S. aureus SAOS5/2 and SAOS51/3. The other staphylococci were DNase negative. S. aureus SAOS1/1 and SAOS51/3 showed biofilm formation on Congo red agar. However, using quantitative plate assay, 12 strains out of 17 showed low-grade biofilm formation (0.1 ≤ A570 < 1), while five strains did not form biofilm (A570 < 0.1). The growth of all strains, including those strains resistant to enterocins, was inhibited by nisin and gallidermin, with high inhibition activity resulting in the inhibition zone in size from 1600 up to 102,400 AU/mL (arbitrary unit per milliliter). This study contributes to microbiota colonization associated with raw ewe's milk lump cheeses; it also indicates bacteriocin treatment benefit, which can be used in prevention and/or elimination of staphylococci.}, } @article {pmid32971319, year = {2021}, author = {Liang, DH and Hu, Y and Liang, D and Chenga, J and Chena, Y}, title = {Bioaugmentation of Moving Bed Biofilm Reactor (MBBR) with Achromobacter JL9 for enhanced sulfamethoxazole (SMX) degradation in aquaculture wastewater.}, journal = {Ecotoxicology and environmental safety}, volume = {207}, number = {}, pages = {111258}, doi = {10.1016/j.ecoenv.2020.111258}, pmid = {32971319}, issn = {1090-2414}, mesh = {Achromobacter/metabolism ; Ammonia ; *Aquaculture ; Biofilms ; Bioreactors/microbiology ; Nitrates ; Nitrogen ; Sulfamethoxazole/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/microbiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {This study investigated whether bioaugmentation improves sulfamethoxazole (SMX) degradation and nitrogen removal in the Moving Bed Biofilm Reactor (MBBR) system. The effects of the C/N ratio on SMX degradation and nitrogen removal were also evaluated. Using MBBR system operation experiments, the bioaugmented reactor was found to perform more effectively than the non-bioaugmentation reactor, with the highest SMX, nitrate-N, and ammonia-N removal efficiencies of 80.49, 94.70, and 96.09%, respectively. The changes in the sulfonamide resistance genes and bacterial communities were detected at various operating conditions. The results indicate that the diversity of the bacterial communities and the abundance of resistance genes were markedly influenced by bioaugmentation and the C/N ratio, with Achromobacter among the dominant genera in the MBBR system. The bio-toxicity of samples, calculated as the inhibition percentage (IP) toward Escherichia coli, was found to decrease to non-toxic ranges after treatment.}, } @article {pmid32970473, year = {2020}, author = {Cacciatore, I and Marinelli, L}, title = {Patent evaluation of US2019338018 (A1) 2019-11-07 (antibody fragments for the treatment of biofilm-related disorders).}, journal = {Expert opinion on therapeutic patents}, volume = {30}, number = {12}, pages = {907-909}, doi = {10.1080/13543776.2020.1828864}, pmid = {32970473}, issn = {1744-7674}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chinchilla ; Ear, Middle/drug effects/microbiology ; Haemophilus Infections/*drug therapy/immunology ; Haemophilus influenzae/drug effects/immunology ; Humans ; Immunoglobulin Fab Fragments/immunology ; Immunoglobulin Fragments/*immunology ; Patents as Topic ; }, abstract = {INTRODUCTION: To date, microbial infections are also difficult to eradicate due to the increasing capability of bacteria to form a biofilm. In the era of antibiotic resistance, antibody-based approaches represent great promise in curing infective pathogens. The authors of US2019338018 patent propose a method for the treatment of biofilm-related disorders by using specific antibody fragments.

AREAS COVERED: The US2019338018 patent reports antibody fragments, pharmaceutical composition that contains it, and their application for the treatment of biofilm-linked disorders. Proof concept and preclinical results show that mAb mIhfB4NTHI Fab caused robust eradication of the biofilm in the middle ear lumen of chinchillas affected by Hemophilus influenzae infection.

EXPERT OPINION: Fab fragments of the US2019338018 patent are new in a general concept to treat bacterial biofilms and biofilm-linked disorders. However, pre-clinical data are only shown for the treatment with Fab fragments of infections caused by H. influenzae in the middle ear of chinchillas. There are no clinical trials that demonstrate that the treatment with Fab fragments may induce a disruption of biofilm produced by H. influenzae or other pathogens and an anti-inflammatory response in infected patients.}, } @article {pmid32969723, year = {2021}, author = {Zhang, Y and Pan, X and Wang, L and Chen, L}, title = {Iron metabolism in Pseudomonas aeruginosa biofilm and the involved iron-targeted anti-biofilm strategies.}, journal = {Journal of drug targeting}, volume = {29}, number = {3}, pages = {249-258}, doi = {10.1080/1061186X.2020.1824235}, pmid = {32969723}, issn = {1029-2330}, mesh = {Acquired Immunodeficiency Syndrome/complications ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cystic Fibrosis/complications ; Drug Resistance, Bacterial ; Humans ; Iron/*metabolism ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/isolation & purification/*physiology ; }, abstract = {Pseudomonas aeruginosa is a gram-negative bacterium that exists in various ecosystems, causing severe infections in patients with AIDS or cystic fibrosis. P. aeruginosa can form biofilm on a variety of surfaces, whereby the bacteria produce defensive substances and enhance antibiotic-resistance, making themselves more adaptable to hostile environments. P. aeruginosa resistance represents one of the main causes of infection-related morbidity and mortality at a global level. Iron is required for the growth of P. aeruginosa biofilm. This review summarises how the iron metabolism contributes to develop biofilm, and more importantly, it may provide some references for the clinic to achieve novel anti-biofilm therapeutics by targeting iron activities.}, } @article {pmid32968946, year = {2021}, author = {Yamamoto, S and Sayed, M and Takahashi, M and Matin, K and Hiraishi, N and Nikaido, T and Burrow, MF and Tagami, J}, title = {Effects of a surface prereacted glass-ionomer filler coating material on biofilm formation and inhibition of dentin demineralization.}, journal = {Clinical oral investigations}, volume = {25}, number = {2}, pages = {683-690}, pmid = {32968946}, issn = {1436-3771}, mesh = {Biofilms ; *Dental Caries ; Dentin ; Glass Ionomer Cements/pharmacology ; Humans ; Streptococcus mutans ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVES: This study investigated the ability of a surface prereacted glass-ionomer (S-PRG) coating material to inhibit the biofilm formation and demineralization of dentin.

METHODS AND MATERIALS: Dentin specimens were randomly divided into three groups: (1) no coating (control), (2) S-PRG filler-containing coat, and (3) a nonS-PRG filler-containing coat. Streptococcus mutans biofilms were grown on the dentin surfaces in a microcosm for 20 h. Then, the quantity of bacteria and water-insoluble glucan in the retained biofilm on the dentin surface were measured. Regarding demineralization inhibition test, specimens were demineralized for 5 days then sectioned into halves and observed under confocal laser scanning microscope (CLSM). One-way ANOVA and Tukey's HSD were used for statistical analysis.

RESULTS: The estimated mean surface roughness for specimens in the S-PRG group was statistically significantly higher than the estimates for both the nonS-PRG and the control group specimens. The quantity of bacteria and water-insoluble glucan/mm[2] revealed that the S-PRG group prevented biofilm formation and bacterial adhesion to the dentin surface compared with the control and nonS-PRG groups. The S-PRG group recorded the highest acid-resistance ability with no surface loss.

CONCLUSION: Application of S-PRG barrier coat on dentin surfaces can inhibit biofilm formation as well as protecting the dentin surface against demineralization.

CLINICAL SIGNIFICANCE: Coating material containing S-PRG fillers might be used for caries prevention, through inhibiting biofilm formation, enhancing mineralization, and reducing acidic attack by cariogenic bacteria.}, } @article {pmid32967183, year = {2020}, author = {Koch, M and Burkovski, A and Zulla, M and Rosiwal, S and Geißdörfer, W and Dittmar, R and Grobecker-Karl, T}, title = {Pilot Study on the Use of a Laser-Structured Double Diamond Electrode (DDE) for Biofilm Removal from Dental Implant Surfaces.}, journal = {Journal of clinical medicine}, volume = {9}, number = {9}, pages = {}, pmid = {32967183}, issn = {2077-0383}, abstract = {No proper treatment option for peri-implantitis exists yet. Based on previous studies showing the in vitro effectiveness of electrochemical disinfection using boron-doped diamond electrodes, novel double diamond electrodes (DDE) were tested here. Using a ceramic carrier and a laser structuring process, a clinically applicable electrode array was manufactured. Roughened metal discs (n = 24) made from Ti-Zr alloy were exposed to the oral cavities of six volunteers for 24 h in order to generate biofilm. Then, biofilm removal was carried out either using plastic curettes and chlorhexidine digluconate or electrochemical disinfection. In addition, dental implants were contaminated with ex vivo multispecies biofilm and disinfected using DDE treatment. Bacterial growth and the formation of biofilm polymer were determined as outcome measures. Chemo-mechanical treatment could not eliminate bacteria from roughened surfaces, while in most cases, a massive reduction of bacteria and biofilm polymer was observed following DDE treatment. Electrochemical disinfection was charge- and time-dependent and could also not reach complete disinfection in all instances. Implant threads had no negative effect on DDE treatment. Bacteria exhibit varying resistance to electrochemical disinfection with Bacillus subtilis, Neisseria sp., Rothiamucilaginosa, Staphylococcus haemolyticus, and Streptococcus mitis surviving 5 min of DDE application at 6 V. Electrochemical disinfection is promising but requires further optimization with respect to charge quantity and application time in order to achieve disinfection without harming host tissue.}, } @article {pmid32963343, year = {2021}, author = {Fernández, L and Gutiérrez, D and García, P and Rodríguez, A}, title = {Environmental pH is a key modulator of Staphylococcus aureus biofilm development under predation by the virulent phage phiIPLA-RODI.}, journal = {The ISME journal}, volume = {15}, number = {1}, pages = {245-259}, pmid = {32963343}, issn = {1751-7370}, mesh = {Animals ; Biofilms ; Computer Simulation ; Hydrogen-Ion Concentration ; Predatory Behavior ; *Staphylococcus Phages/genetics ; *Staphylococcus aureus ; }, abstract = {Previous work had shown that, in some Staphylococcus aureus strains, low concentrations of the virulent phage vB_SauM_phiIPLA-RODI (phiIPLA-RODI) promoted the formation of DNA-rich biofilms, whose cells exhibited significant transcriptional differences compared to an uninfected control. This study aimed to dissect the sequence of events leading to these changes. Analysis of phage propagation throughout biofilm development revealed that the number of phage particles increased steadily up to a certain point and then declined. This partial phage inactivation seemed to be a consequence of medium acidification due to glucose fermentation by the bacterium. Computer simulation of phage-host dynamics during biofilm development showed how even small differences in pH evolution can affect the outcome of phage infection. An acidic pH, together with successful phage propagation, was also necessary to observe the phage-associated changes in biofilm architecture and in the transcriptional profile of the bacterial population. Altogether, this study shows how the dynamics between phage and host can be tightly coordinated through an environmental cue, even in the context of a complex biofilm population.}, } @article {pmid32963304, year = {2020}, author = {Leulmi Pichot, S and Joisten, H and Grant, AJ and Dieny, B and Cowburn, RP}, title = {Magneto-mechanically actuated microstructures to efficiently prevent bacterial biofilm formation.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {15470}, pmid = {32963304}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Bacterial Adhesion ; Biofilms/drug effects/*growth & development ; Escherichia coli/drug effects/*growth & development ; Escherichia coli Infections/microbiology/*prevention & control ; Humans ; *Magnetics ; Microtechnology/*instrumentation ; Particle Size ; Surface Properties ; }, abstract = {Biofilm colonisation of surfaces is of critical importance in various areas ranging from indwelling medical devices to industrial setups. Of particular importance is the reduced susceptibility of bacteria embedded in a biofilm to existing antimicrobial agents. In this paper, we demonstrate that remotely actuated magnetic cantilevers grafted on a substrate act efficiently in preventing bacterial biofilm formation. When exposed to an alternating magnetic field, the flexible magnetic cantilevers vertically deflect from their initial position periodically, with an extremely low frequency (0.16 Hz). The cantilevers' beating prevents the initial stage of bacterial adhesion to the substrate surface and the subsequent biofilm growth. Our experimental data on E. coli liquid cultures demonstrate up to a 70% reduction in biofilm formation. A theoretical model has been developed to predict the amplitude of the cantilevers vertical deflection. Our results demonstrate proof-of-concept for a device that can magneto-mechanically prevent the first stage in bacterial biofilm formation, acting as on-demand fouling release active surfaces.}, } @article {pmid32959147, year = {2021}, author = {Elumalai, P and AlSalhi, MS and Mehariya, S and Karthikeyan, OP and Devanesan, S and Parthipan, P and Rajasekar, A}, title = {Bacterial community analysis of biofilm on API 5LX carbon steel in an oil reservoir environment.}, journal = {Bioprocess and biosystems engineering}, volume = {44}, number = {2}, pages = {355-368}, pmid = {32959147}, issn = {1615-7605}, support = {EEQ/2016/000449//Science and Engineering Research Board/ ; RSP-2019/68//Researchers Supporting Project/ ; }, mesh = {Biofilms/*growth & development ; Marinobacter/*physiology ; Microbial Consortia/*physiology ; *Mineral Oil ; *Steel ; }, abstract = {This study aimed to characterize the biofilm microbial community that causes corrosion of API 5LX carbon steel. API 5LX carbon steel coupons were incubated with raw produced water collected from two oil reservoir stations or filter-sterilized produced water. Biofilm 16S rRNA amplicon sequencing revealed that the bacterial community present in the biofilm was dominated by Proteobacteria, including Marinobacter hydrocarbonoclaustics and Marinobacter alkaliphilus. Electrochemical analysis such as impedance and polarization results indicated that Proteobacteria biofilm accelerated corrosion by ~ twofold (2.1 ± 0.61 mm/years) or ~ fourfold (~ 3.7 ± 0.42 mm/years) when compared to the control treatment (0.95 ± 0.1 mm/years). Scanning electron and atomic force microscopy revealed the presence of a thick biofilm and pitting corrosion. X-ray diffraction revealed higher amounts of the corrosion products Fe2O3, γ-FeOOH, and α-FeOOH, and confirmed that the microbial biofilm strongly oxidized the iron and contributed to the acceleration of corrosion of carbon metal API 5LX.}, } @article {pmid32958848, year = {2021}, author = {Chan, SY and Liu, SY and Seng, Z and Chua, SL}, title = {Biofilm matrix disrupts nematode motility and predatory behavior.}, journal = {The ISME journal}, volume = {15}, number = {1}, pages = {260-269}, pmid = {32958848}, issn = {1751-7370}, mesh = {Animals ; Biofilms ; Caenorhabditis elegans ; *Extracellular Polymeric Substance Matrix ; Polysaccharides, Bacterial ; *Predatory Behavior ; Pseudomonas aeruginosa ; }, abstract = {In nature, bacteria form biofilms by producing exopolymeric matrix that encases its entire community. While it is widely known that biofilm matrix can prevent bacterivore predation and contain virulence factors for killing predators, it is unclear if they can alter predator motility. Here, we report a novel "quagmire" phenotype, where Pseudomonas aeruginosa biofilms could retard the motility of bacterivorous nematode Caenorhabditis elegans via the production of a specific exopolysaccharide, Psl. Psl could reduce the roaming ability of C. elegans by impeding the slithering velocity of C. elegans. Furthermore, the presence of Psl in biofilms could entrap C. elegans within the matrix, with dire consequences to the nematode. After being trapped in biofilms, C. elegans could neither escape effectively from aversive stimuli (noxious blue light), nor leave easily to graze on susceptible biofilm areas. Hence, this reduced the ability of C. elegans to roam and predate on biofilms. Taken together, our work reveals a new function of motility interference by specific biofilm matrix components, and emphasizes its importance in predator-prey interactions.}, } @article {pmid32958735, year = {2020}, author = {Kim, YJ and Yu, HH and Park, YJ and Lee, NK and Paik, HD}, title = {Anti-Biofilm Activity of Cell-Free Supernatant of Saccharomyces cerevisiae against Staphylococcus aureus.}, journal = {Journal of microbiology and biotechnology}, volume = {30}, number = {12}, pages = {1854-1861}, pmid = {32958735}, issn = {1738-8872}, mesh = {Anti-Bacterial Agents/metabolism/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Saccharomyces cerevisiae/*metabolism ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus is one of the most common microorganisms and causes foodborne diseases. In particular, biofilm-forming S. aureus is more resistant to antimicrobial agents and sanitizing treatments than planktonic cells. Therefore, this study aimed to investigate the anti-biofilm effects of cell-free supernatant (CFS) of Saccharomyces cerevisiae isolated from cucumber jangajji compared to grapefruit seed extract (GSE). CFS and GSE inhibited and degraded S. aureus biofilms. The adhesion ability, auto-aggregation, and exopolysaccharide production of CFS-treated S. aureus, compared to those of the control, were significantly decreased. Moreover, biofilm-related gene expression was altered upon CFS treatment. Scanning electron microscopy images confirmed that CFS exerted anti-biofilm effects against S. aureus. Therefore, these results suggest that S. cerevisiae CFS has anti-biofilm potential against S. aureus strains.}, } @article {pmid32957050, year = {2021}, author = {Zheng, Z and Li, J and Chen, G and Peng, Y}, title = {Exploring the optimized strategy in the nitritation-anammox biofilm process for treating low ammonium wastewater.}, journal = {Bioresource technology}, volume = {319}, number = {}, pages = {124113}, doi = {10.1016/j.biortech.2020.124113}, pmid = {32957050}, issn = {1873-2976}, mesh = {*Ammonium Compounds/analysis ; Biofilms ; Bioreactors ; Denitrification ; Extracellular Polymeric Substance Matrix ; Nitrogen ; Oxidation-Reduction ; Sewage ; *Wastewater ; }, abstract = {The main challenge for achieving the simultaneous nitritation, anammox and denitrification (SNAD) process is to optimize the concentrations of nitrite and dissolved oxygen (DO). This study explored the performance of SNAD biofilm reactor under three operational strategies. At Stage 1, 2 and 3, the average concentrations of DO were 0.7, 2.7 and 5.2 mg/L, respectively. The peak concentrations of NO2[-]-N in the sequencing batch reactor (SBR) cycle were 5.3, 6.0 and 2.7 mg/L, respectively. The average removal rates of total inorganic nitrogen (TIN) were 0.30, 0.42 and 0.22 kg N/m[3]/d, respectively. Protein (PN) was the dominant extracellular polymeric substance (EPS) content on the SNAD biofilm. The PN concentration remained stable while the polysaccharide (PS) concentration changed rapidly under different operational strategies. High-throughput sequencing analysis indicated that high DO and long aeration period condition could lead to a slight decrease in the abundances of denitrifying bacteria and anammox bacteria.}, } @article {pmid32954847, year = {2020}, author = {Sidrim, JJ and Ocadaque, CJ and Amando, BR and de M Guedes, GM and Costa, CL and Brilhante, RS and A Cordeiro, R and Rocha, MF and Scm Castelo-Branco, D}, title = {Rhamnolipid enhances Burkholderia pseudomallei biofilm susceptibility, disassembly and production of virulence factors.}, journal = {Future microbiology}, volume = {15}, number = {}, pages = {1109-1121}, doi = {10.2217/fmb-2020-0010}, pmid = {32954847}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects ; Burkholderia pseudomallei/*drug effects/genetics/growth & development/physiology ; Ceftazidime/pharmacology ; Glycolipids/*pharmacology ; Microbial Sensitivity Tests ; Siderophores/metabolism ; Virulence Factors/genetics/*metabolism ; }, abstract = {Aim: This study evaluated the effect of the biosurfactant rhamnolipid on the antimicrobial susceptibility, biofilm growth dynamics and production of virulence factors by Burkholderia pseudomallei. Materials & methods: The effects of rhamnolipid on planktonic and biofilm growth and its interaction with antibacterial drugs were evaluated. Then, its effects on growing and mature biofilms and on protease and siderophore production were assessed. Results: Rhamnolipid did not inhibit B. pseudomallei growth, but significantly enhanced the activity of meropenem and amoxicillin-clavulanate against mature biofilms. Rhamnolipid significantly reduced the biomass of mature biofilms, significantly increased protease production by growing and mature biofilms and siderophore release by growing biofilms. Conclusion: Rhamnolipid enhances the antimicrobial activity against B. pseudomallei, assists biofilm disassembly and alters protease and siderophore production by bacterial biofilms.}, } @article {pmid32954115, year = {2020}, author = {Li, Y and Xiao, P and Wang, Y and Hao, Y}, title = {Mechanisms and Control Measures of Mature Biofilm Resistance to Antimicrobial Agents in the Clinical Context.}, journal = {ACS omega}, volume = {5}, number = {36}, pages = {22684-22690}, pmid = {32954115}, issn = {2470-1343}, abstract = {Biofilms are the aggregation of micro-organisms, which are composed of extracellular polymeric substance (EPS) and many other biochemical components. Though they might be beneficial to some wastewater and soil treatment processes, they may expose chronic infection and risk to personal hygiene in the industrial as well as the clinical context. Despite having a well-established disinfection and hygiene monitoring program for the prevention of formation and growth, biofilm persistently remains in the medical settings because of its antibiotic resistance to antimicrobial agents and even the immune system. In this paper, the contributing factors of antibiotic resistance and the corresponding mechanisms, including heterogeneity inside biofilms, the roles of the EPS matrix, cell density, and quorum sensing, and cell mutability, are reviewed. Moreover, current clinical practice and strategic applications are also suggested to address the biofilm resistance issues.}, } @article {pmid32953787, year = {2020}, author = {Feng, E and Shen, K and Lin, F and Lin, W and Zhang, T and Zhang, Y and Lin, F and Yang, Y and Lin, C}, title = {Improved osteogenic activity and inhibited bacterial biofilm formation on andrographolide-loaded titania nanotubes.}, journal = {Annals of translational medicine}, volume = {8}, number = {16}, pages = {987}, pmid = {32953787}, issn = {2305-5839}, abstract = {BACKGROUND: Delivery of local drugs with a titania nanotube is an attractive approach to combat implant-related infection. Our earlier study has confirmed that nanotubes loaded with gentamicin could significantly improve the antibacterial ability. On this basis, the used andrographolide in this paper has a high antibacterial activity, which cannot only avoid the evolution of antibiotic-resistant bacteria but also has simultaneously excellent biocompatibility with osteogenic cells.

METHODS: Two mg of andrographolide was loaded into titania nanotubes, which were fabricated into different diameters (50 and 100 nm) and 200 nm length by the method of lyophilization and vacuum drying. We chose a standard strain, Staphylococcus epidermidis (American Type Culture Collection 35984), and two clinical isolates, S. aureus 376 and S. epidermidis 389 to research the bacterial adhesion at 6, 12 and 24 hours and biofilm formation at 48, and 72 hours on the andrographolide-loaded nanotubes (NT-A) using the diffusion plate method. Smooth titanium (smooth Ti) and nanotubes with no drug loading (NT) were also inclusive and analyzed. Furthermore, the Sprague-Dawley (SD) rats mesenchymal stem cells were used to assess the influence of nanotubular topographies on the osteogenic differentiation of mesenchymal stem cells.

RESULTS: Our results showed that NT-A could inhibit bacterial adhesion and biofilm formation on implant surfaces. NT-A and NT, especially those with 100 nm diameters, were found to significantly promoted cell attachment, proliferation, diffusion, and osteogenic differentiation when compared with smooth Ti, while the same diameter in NT-A and NT did not differ.

CONCLUSIONS: Titania nanotube modification and andrographolide loading can significantly improve the antibacterial ability and osteogenic activity of orthopedic implants. Nanotubes-based local delivery could be a promising strategy for combating implant-associated infection.}, } @article {pmid32951490, year = {2020}, author = {Luo, Y and Yang, Q and Li, B and Yao, Y}, title = {Establishment of a quality control circle to reduce biofilm formation in flexible endoscopes by improvement of qualified cleaning rate.}, journal = {The Journal of international medical research}, volume = {48}, number = {9}, pages = {300060520952983}, pmid = {32951490}, issn = {1473-2300}, mesh = {Biofilms ; China ; *Disinfection ; Endoscopes ; *Equipment Contamination ; Humans ; Quality Control ; }, abstract = {OBJECTIVE: In recent years, the Emergency Care Research Institute has advised that endoscope cleaning is of considerable importance. In the present study, a quality control circle (QCC) was used to reduce the formation of biofilms in flexible endoscopes within one hospital in Guangdong Province, China.

METHODS: During reprocessing of 235 flexible endoscopes in the urology surgical suite, adenosine triphosphate (ATP) detection was used to monitor the efficacy of biofilm removal. The internal and external parts of flexible endoscopes were used as sampling sites by means of the flushing and smudge methods, respectively. When the two results reached the standard of less than 500 relative light units/piece at the same time, endoscopic biofilm clearance was considered to be qualified. A QCC was established to implement a 10-step plan-do-check-act model.

RESULTS: The baseline qualified rate (i.e., ATP monitoring pass rate) during reprocessing of 235 flexible endoscopes was 50%. During the study, the qualified rate increased to 85.29% after establishment of the QCC. During reprocessing of 150 flexible endoscopes in the following 6 months, the qualified rate remained at 90%.

CONCLUSION: Establishment of the QCC improved the removal of biofilm from flexible endoscopes in the urology surgical suite.}, } @article {pmid32950174, year = {2020}, author = {Mendez, E and Walker, DK and Vipham, J and Trinetta, V}, title = {The use of a CDC biofilm reactor to grow multi-strain Listeria monocytogenes biofilm.}, journal = {Food microbiology}, volume = {92}, number = {}, pages = {103592}, doi = {10.1016/j.fm.2020.103592}, pmid = {32950174}, issn = {1095-9998}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Centers for Disease Control and Prevention, U.S. ; Culture Media/metabolism ; Food-Processing Industry/instrumentation ; Listeria monocytogenes/*growth & development/physiology ; Stainless Steel/analysis ; United States ; }, abstract = {Listeria monocytogenes is one of the most concerning pathogens for the food industry due to its ability to form biofilms, particularly in difficult-to-clean sites of processing facilities. There is a current industry-wide lack of data to refer to when selecting a strategy to control L. monocytogenes biofilms in the food premises. Many strategies have been developed to study biofilm formation of bacteria; however, few have targeted L. monocytogenes biofilms under dynamic conditions. This study addresses the biofilm formation ability of L. monocytogenes on stainless steel and polycarbonate under dynamic conditions using TSBYE or BHI as media culture at 30 °C or 37 °C. Higher cell counts were recovered at 30 °C in TSBYE on polycarbonate while lower counts were obtained at 37 °C in BHI on stainless steel (P < 0.05). Nonetheless, all factors (temperature, media and material) were statistically significant (P < 0.05) and an interaction between temperature and media was observed (P < 0.05). To our knowledge, this work represents an initial framework to develop L. monocytogenes biofilms under different dynamic conditions. The use of CDC Biofilm Reactor is not widely used yet in the food industry and represent a novel approach to help sanitary control strategies implementation.}, } @article {pmid32949024, year = {2020}, author = {Zhang, N and Chang, YG and Tseng, R and Ovchinnikov, S and Schwarz, R and LiWang, A}, title = {Solution NMR structure of Se0862, a highly conserved cyanobacterial protein involved in biofilm formation.}, journal = {Protein science : a publication of the Protein Society}, volume = {29}, number = {11}, pages = {2274-2280}, pmid = {32949024}, issn = {1469-896X}, support = {R01 GM129325/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/*chemistry ; *Biofilms ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; *Synechococcus/chemistry/physiology ; }, abstract = {Biofilms are accumulations of microorganisms embedded in extracellular matrices that protect against external factors and stressful environments. Cyanobacterial biofilms are ubiquitous and have potential for treatment of wastewater and sustainable production of biofuels. But the underlying mechanisms regulating cyanobacterial biofilm formation are unclear. Here, we report the solution NMR structure of a protein, Se0862, conserved across diverse cyanobacterial species and involved in regulation of biofilm formation in the cyanobacterium Synechococcus elongatus PCC 7942. Se0862 is a class α+β protein with ααββββαα topology and roll architecture, consisting of a four-stranded β-sheet that is flanked by four α-helices on one side. Conserved surface residues constitute a hydrophobic pocket and charged regions that are likely also present in Se0862 orthologs.}, } @article {pmid32948964, year = {2020}, author = {Sharma, K and Bose, SK and Chhibber, S and Harjai, K}, title = {Exploring the Therapeutic Efficacy of Zingerone Nanoparticles in Treating Biofilm-Associated Pyelonephritis Caused by Pseudomonas aeruginosa in the Murine Model.}, journal = {Inflammation}, volume = {43}, number = {6}, pages = {2344-2356}, pmid = {32948964}, issn = {1573-2576}, support = {DST-INSPIRE # IF140915//Department of Science and Technology, Goverment of India/ ; }, mesh = {Animals ; Biofilms ; Disease Models, Animal ; Guaiacol/*analogs & derivatives/pharmacology ; HEK293 Cells ; Humans ; Inflammation ; Malondialdehyde ; Mice ; Microscopy, Electron, Scanning ; Nanoparticles/*chemistry ; Peroxidase ; Phagocytosis ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*metabolism ; Pyelonephritis/*drug therapy/metabolism ; Stem Cells ; Tetrazolium Salts/chemistry ; Thiazoles/chemistry ; }, abstract = {Biofilms of Pseudomonas aeruginosa can cause complicated urinary tract infections especially in people with indwelling catheters which may result in pyelonephritis. Microorganisms in biofilm demonstrate high resistance to both antibiotics and host protection mechanisms, often resulting in chronic and difficult-to-treat infections. This study is aimed to assess in vivo and ex vivo efficacy of Zingerone nanoparticles (Z-NPs) against P. aeruginosa biofilm-associated murine acute pyelonephritis. In the present study, Zingerone and chitosan acted synergistically in the form of Z-NPs and found to be nontoxic to the kidney cell lines as depicted in MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay demonstrating their cytocompatibility. In vivo experiments indicated that Z-NPs (100 mg/kg) treatment reduced P. aeruginosa pathogenicity and enhanced the clearance of bacterial count from the renal and bladder tissue. Z-NPs improved the disease outcome by lowering the levels of various inflammatory markers, and histopathological examination revealed better recovery in renal and bladder tissue. Besides, ex vivo efficacy also confirmed that Z-NPs enhanced serum bactericidal effect along with increased phagocytic uptake and intracellular killing of P. aeruginosa as confirmed by fluorescent microscopy. To the best of our knowledge, this is the first study to provide evidence that Z-NPs are effective therapeutic agents for combating P. aeruginosa associated pyelonephritis.}, } @article {pmid32948018, year = {2020}, author = {Brum, RS and Labes, LG and Volpato, CÂM and Benfatti, CAM and Pimenta, AL}, title = {Strategies to Reduce Biofilm Formation in PEEK Materials Applied to Implant Dentistry-A Comprehensive Review.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32948018}, issn = {2079-6382}, support = {1269_2017//ITI Foundation/ ; }, abstract = {Polyether-ether-ketone (PEEK) has emerged in Implant Dentistry with a series of short-time applications and as a promising material to substitute definitive dental implants. Several strategies have been investigated to diminish biofilm formation on the PEEK surface aiming to decrease the possibility of related infections. Therefore, a comprehensive review was carried out in order to compare PEEK with materials widely used nowadays in Implant Dentistry, such as titanium and zirconia, placing emphasis on studies investigating its ability to grant or prevent biofilm formation. Most studies failed to reveal significant antimicrobial activity in pure PEEK, while several studies described new strategies to reduce biofilm formation and bacterial colonization on this material. Those include the PEEK sulfonation process, incorporation of therapeutic and bioactive agents in PEEK matrix or on PEEK surface, PEEK coatings and incorporation of reinforcement agents, in order to produce nanocomposites or blends. The two most analyzed surface properties were contact angle and roughness, while the most studied bacteria were Escherichia coli and Staphylococcus aureus. Despite PEEK's susceptibility to biofilm formation, a great number of strategies discussed in this study were able to improve its antibiofilm and antimicrobial properties.}, } @article {pmid32947746, year = {2020}, author = {Ahamed, T and Brown, SP and Salehi, M}, title = {Investigate the role of biofilm and water chemistry on lead deposition onto and release from polyethylene: An implication for potable water pipes.}, journal = {Journal of hazardous materials}, volume = {400}, number = {}, pages = {123253}, doi = {10.1016/j.jhazmat.2020.123253}, pmid = {32947746}, issn = {1873-3336}, mesh = {Adsorption ; Biofilms ; *Drinking Water ; Hydrogen-Ion Concentration ; Kinetics ; Lead ; Polyethylene ; *Water Pollutants, Chemical/analysis ; }, abstract = {In this study, the influence of biofilm presence and water chemistry conditions on lead (Pb) deposition onto low density polyethylene (LDPE) surface was examined. The results demonstrated that biofilm presence on LDPE surfaces strongly and significantly enhanced Pb uptake, with the 13-fold greater equilibrium Pb surface loading when biofilm was present (1602 μg/m[2]) compared to the condition when it was absent (124 μg/m[2]). The kinetics of Pb adsorption onto LDPE surface when biofilm was present is best described by Pseudo 2nd order kinetic model. Pb adsorption onto new LDPE surfaces was significantly reduced from 1101 μg/m[2] to 134 μg/m[2] with increased aqueous solution's ionic strength from 3 × 10[-6] M to 0.0072 M. The presence of chlorine residual (2 mg/L) significantly reduced Pb adsorption onto LDPE surfaces by possible oxidation of Pb[2+] to Pb[4+] species. The kinetics of Pb release from LDPE surfaces was investigated under static and dynamic conditions through immediate exposure of Pb accumulated LDPE pellets to the synthetic water at pH 5.0 and 7.8. The results demonstrated a greater Pb release (86 %) at pH 5.0 compared to the pH 7.8 (58 %). An enhanced Pb release into the contact water was found under dynamic conditions compared to static conditions.}, } @article {pmid32946923, year = {2020}, author = {Hutchins, CF and Moore, G and Webb, J and Walker, JT}, title = {Investigating alternative materials to EPDM for automatic taps in the context of Pseudomonas aeruginosa and biofilm control.}, journal = {The Journal of hospital infection}, volume = {106}, number = {3}, pages = {429-435}, doi = {10.1016/j.jhin.2020.09.013}, pmid = {32946923}, issn = {1532-2939}, mesh = {Bacterial Load/statistics & numerical data ; Biofilms/*growth & development ; Disease Reservoirs/*microbiology ; Drinking Water/*microbiology ; Health Facilities/standards ; Manufactured Materials/*microbiology ; Nitriles ; Pseudomonas aeruginosa/*physiology ; Rubber ; Silicones ; Water Microbiology ; }, abstract = {BACKGROUND: Automatic taps use solenoid valves (SVs) which incorporate a rubber (typically EPDM) diaphragm to control water flow. Contaminated SVs can be reservoirs of opportunistic pathogens such as Pseudomonas aeruginosa; an important cause of healthcare-associated infection.

AIMS: To investigate the attachment and biofilm formation of P. aeruginosa on EPDM and relevant alternative rubbers to assess the impact on water hygiene in a laboratory model.

METHODS: Biofilm formation on EPDM, silicone and nitrile rubber coupons was investigated using a CDC biofilm reactor. SVs incorporating EPDM or nitrile rubber diaphragms were installed on to an experimental water distribution system (EWDS) and inoculated with P. aeruginosa. P. aeruginosa water levels were monitored for 12-weeks. SVs incorporating diaphragms (EPDM, silicone or silver ion-impregnated silicone rubber), pre-colonized with P. aeruginosa, were installed and the effect of flushing as a control measure was investigated. The concentration of P. aeruginosa in the water was assessed by culture and biofilm assessed by culture and microscopy.

FINDINGS: Bacterial attachment was significantly higher on nitrile (6.2 × 10[5] cfu/coupon) and silicone (5.4 × 10[5] cfu/coupon) rubber than on EPDM (2.9 ×10[5] cfu/coupon) (P<0.05, N = 17). Results obtained in vitro did not translate to the EWDS where, after 12-weeks in situ, there was no significant difference in P. aeruginosa water levels or biofilm levels. Flushing caused a superficial reduction in bacterial counts after <5 min of stagnation.

CONCLUSION: This study did not provide evidence to support replacement of EPDM with (currently available) alternative rubbers and indicated the first sample of water dispensed from a tap should be avoided for use in healthcare settings.}, } @article {pmid32944156, year = {2020}, author = {Ishikawa, KH and Mita, D and Kawamoto, D and Nicoli, JR and Albuquerque-Souza, E and Lorenzetti Simionato, MR and Mayer, MPA}, title = {Probiotics alter biofilm formation and the transcription of Porphyromonas gingivalis virulence-associated genes.}, journal = {Journal of oral microbiology}, volume = {12}, number = {1}, pages = {1805553}, pmid = {32944156}, issn = {2000-2297}, abstract = {BACKGROUND AND OBJECTIVE: The potential of probiotics on the prevention and control of periodontitis and other chronic inflammatory conditions has been suggested. Lactobacillus and Bifidobacterium species influence P. gingivalis interaction with gingival epithelial cells (GECs) but may not act in a unique way. In order to select the most appropriate probiotic against P. gingivalis, we aimed to evaluate the effect of several strains on Porphyromonas gingivalis biofilm formation and transcription virulence-associated factors (PgVAFs).

METHODS: Cell-free pH neutralized supernatants (CFS) and living Lactobacillus spp. and Bifidobacterium spp. were tested against P. gingivalis ATCC 33277 and W83, in mono- and multi-species (with Streptococcus oralis and S. gordonii) biofilms. Relative transcription of P. gingivalis genes (fimA, mfa1, kgp, rgp, ftsH and luxS) was determined in biofilms and under GECs co-infection.

RESULTS: Probiotics CFS reduced P. gingivalis ATCC 33277 levels in mono-species biofilms and living probiotics reduced P. gingivalis abundance in multi-species biofilms. L. acidophilus LA5 down-regulated transcription of most PgVAFs in biofilms and GECs.

CONCLUSIONS: Probiotics affect P. gingivalis biofilm formation by down-regulating overall PgVAFs with the most pronounced effect observed for L. acidophilus LA5.}, } @article {pmid32943252, year = {2021}, author = {Portell-Buj, E and López-Gavín, A and González-Martín, J and Tudó, G}, title = {In Vitro Biofilm Formation in Mycobacterium avium-intracellulare Complex.}, journal = {Archivos de bronconeumologia}, volume = {57}, number = {2}, pages = {140-141}, doi = {10.1016/j.arbres.2020.07.028}, pmid = {32943252}, issn = {2173-5751}, mesh = {Biofilms ; Humans ; Mycobacterium avium ; *Mycobacterium avium Complex ; *Mycobacterium avium-intracellulare Infection ; }, } @article {pmid32942620, year = {2020}, author = {Cuevas, JP and Moraga, R and Sánchez-Alonzo, K and Valenzuela, C and Aguayo, P and Smith, CT and García, A and Fernandez, Í and Campos, VL}, title = {Characterization of the Bacterial Biofilm Communities Present in Reverse-Osmosis Water Systems for Haemodialysis.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32942620}, issn = {2076-2607}, abstract = {Biofilm in reverse osmosis (RO) membranes is a common problem in water treatment at haemodialysis facilities. Bacteria adhere and proliferate on RO membranes, forming biofilms, obstructing and damaging the membranes and allowing the transfer of bacteria and/or cellular components potentially harmful to the health of haemodialysis patients. Our aim was to characterize the bacterial community associated to biofilm of RO membranes and to identify potentially pathogenic bacteria present in the haemodialysis systems of two dialysis centres in Chile. The diversity of the bacterial communities present on RO membranes and potable and osmosed water samples was evaluated using Illumina sequencing. Additionally, bacteria from potable water, osmosed water and RO membrane samples were isolated, characterized and identified by Sanger's sequencing. The molecular analyses of metagenomics showed that the phyla having a greater relative abundance in both dialysis centres were Proteobacteria and Planctomycetes. Pseudomonas, Stenotrophomonas, Agrobacterium, Pigmentiphaga, Ralstonia, Arthrobacter, Bacteroides and Staphylococcus were bacterial genera isolated from the different samples obtained at both haemodialysis centres. Pseudomonas spp. was a bacterial genus with greater frequency in all samples. Pseudomonas and Staphylococcus showed higher levels of resistance to the antibiotics tested. Results demonstrated the presence of potentially pathogenic bacteria, showing resistance to antimicrobials on RO membranes and in osmosed water in both dialysis centres studied.}, } @article {pmid32941438, year = {2020}, author = {Alvendal, C and Mohanty, S and Bohm-Starke, N and Brauner, A}, title = {Anti-biofilm activity of chlorhexidine digluconate against Candida albicans vaginal isolates.}, journal = {PloS one}, volume = {15}, number = {9}, pages = {e0238428}, pmid = {32941438}, issn = {1932-6203}, mesh = {Adult ; Antifungal Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Candida/drug effects ; Candida albicans/*drug effects/isolation & purification ; Candidiasis/drug therapy ; Candidiasis, Vulvovaginal/drug therapy/microbiology ; Chlorhexidine/*analogs & derivatives/metabolism/pharmacology ; Female ; Fluconazole/pharmacology ; Humans ; Microbial Sensitivity Tests/methods ; Vagina/microbiology ; }, abstract = {OBJECTIVES: Recurrent vulvovaginal candidiasis (RVVC) causes significant morbidity. Candida albicans is the main pathogen associated with both sporadic and recurrent candidiasis. Due to unsatisfactory treatment effect, the impact of chlorhexidine digluconate and fluconazole alone or in combination on C. albicans and biofilm was investigated.

METHODS: Vaginal C. albicans isolates from 18 patients with recurrent candidiasis and commensals from 19 asymptomatic women were isolated by culture. Crystal violet, XTT and colony forming unit assay were used to analyze the effect of chlorhexidine digluconate and fluconazole on growth of C. albicans, formation of new and already established, mature, biofilm.

RESULTS: Fluconazole reduced the growth of planktonic C. albicans. However, in established biofilm, fluconazole had no effect on the candida cells and was not able to disperse and reduce the biofilm. By contrast, chlorhexidine digluconate had a direct killing effect on C. albicans grown both planktonically and in biofilm. Chlorhexidine digluconate also dispersed mature biofilm and inhibited formation of new biofilm. No major differences were observed between commensal isolates and candida causing recurrent vulvovaginitis with respect to biofilm or growth after chlorhexidine digluconate treatment.

CONCLUSION: Biofilm is a problem in patients with recurrent vulvovaginal candidiasis reducing the effect of antifungal treatment. Development of new treatment strategies are urgently needed to decrease the recurrences. In already established biofilm, chlorhexidine digluconate dispersed the biofilm and was more effective in eradicating candida compared to fluconazole. Future treatment strategy may thus be a combination of chlorhexidine digluconate and fluconazole and prophylactic use of chlorhexidine digluconate to prevent biofilm formation and restrict infections.}, } @article {pmid32939990, year = {2020}, author = {Liang, M and Wang, Y and Ma, K and Yu, S and Chen, Y and Deng, Z and Liu, Y and Wang, F}, title = {Engineering Inorganic Nanoflares with Elaborate Enzymatic Specificity and Efficiency for Versatile Biofilm Eradication.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {16}, number = {41}, pages = {e2002348}, doi = {10.1002/smll.202002348}, pmid = {32939990}, issn = {1613-6829}, mesh = {Biofilms ; Catalysis ; *Metal Nanoparticles ; *Platinum ; Prospective Studies ; }, abstract = {Nanozyme has emerged as a versatile nanocatalyst yet is constrained with limited catalytic efficiency and specificity for various biomedical applications. Herein, by elaborately integrating the recognition/transduction carbon dots (CDs) with platinum nanoparticles (PtNPs), an exquisite CDs@PtNPs (CPP) nanoflare is engineered as an efficient and substrate-specific peroxidase-mimicking nanozyme for high-performance biosensing and antibacterial applications. The intelligent CPP-catalyzed hydrogen peroxide (H2 O2)-generated reactive oxygen species realize the sensitive diagnosis-guided enhanced disinfection of pathogens. Significantly, the CPP nanozyme shows the prominent biofilm eradication and wound healing in vivo by virtue of endogenous H2 O2 in acidic infection tissues, which can substantially preclude the annoying antibiotics resistance. A fundamental understanding on the present CPP nanoflare would not only facilitate the advancement of various prospective biocatalysts, but also establish a multifunctional means for versatile biosensing and smart diagnostic applications.}, } @article {pmid32938382, year = {2020}, author = {Steiger, EL and Muelli, JR and Braissant, O and Waltimo, T and Astasov-Frauenhoffer, M}, title = {Effect of divalent ions on cariogenic biofilm formation.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {287}, pmid = {32938382}, issn = {1471-2180}, mesh = {Bacterial Adhesion ; Biofilms/*drug effects/growth & development ; Calcium/*pharmacology ; Cations, Divalent ; Dental Caries/microbiology/pathology ; Durapatite ; Fructose/metabolism/pharmacology ; Glucose/metabolism/pharmacology ; Humans ; Magnesium/*pharmacology ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial ; Streptococcal Infections/microbiology/pathology ; Streptococcus mutans/*drug effects/genetics/growth & development/isolation & purification ; Sucrose/metabolism/pharmacology ; Zinc/*pharmacology ; }, abstract = {BACKGROUND: Divalent cations are able to interact with exopolysaccharides (EPS) and thus are capable to modify the structure and composition of dental biofilm. At the moment, little is known about the adsorption of metals by cariogenic EPS; thus, the aim of the present study was to evaluate the effect of divalent ions (calcium, magnesium, and zinc) on the growth and biofilm formation of mutans streptococci and on the dissolution of hydroxyapatite as well as to investigate their binding to the bacterial EPS.

RESULTS: S. mutans strains used in this study show the highest tolerance towards calcium of the ions tested. Growth parameters showed no differences to control condition for both strains up to 100 mM; revealing natural tolerance to higher concentration of calcium in the surroundings. Although excessive levels of calcium did not impair the growth parameters, it also did not have a positive effect on biofilm formation or its binding affinity to EPS. Magnesium-saturated environment proved to be counterproductive as strains were able to dissolve more Ca[2+] from the tooth surface in the presence of magnesium, therefore releasing excessive amounts of Ca[2+] in the environment and leading to the progression of the disease. Thus, this supports the idea of self-regulation, when more Ca[2+] is released, more calcium is bound to the biofilm strengthening its structure and however, also less is left for remineralization. Zinc inhibited bacterial adhesion already at low concentrations and had a strong antibacterial effect on the strains as well as on calcium dissolution; leading to less biofilm and less EPS. Additionally, Zn[2+] had almost always the lowest affinity to all EPS; thus, the unbound zinc could also still remain in the surrounding environment and keep its antimicrobial properties.

CONCLUSION: It is important to maintain a stable relationship between calcium, magnesium and zinc as excessive concentrations of one can easily destroy the balance between the three in cariogenic environment and lead to progression of the disease.}, } @article {pmid32937742, year = {2020}, author = {Ribeiro-Vidal, H and Sánchez, MC and Alonso-Español, A and Figuero, E and Ciudad, MJ and Collado, L and Herrera, D and Sanz, M}, title = {Antimicrobial Activity of EPA and DHA against Oral Pathogenic Bacteria Using an In Vitro Multi-Species Subgingival Biofilm Model.}, journal = {Nutrients}, volume = {12}, number = {9}, pages = {}, pmid = {32937742}, issn = {2072-6643}, mesh = {Analysis of Variance ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Docosahexaenoic Acids/*pharmacology ; Eicosapentaenoic Acid/*pharmacology ; Gingiva/microbiology ; Humans ; Microbial Viability/*drug effects ; Microscopy, Confocal ; Models, Biological ; Real-Time Polymerase Chain Reaction ; }, abstract = {In search for natural products with antimicrobial properties for use in the prevention and treatment of periodontitis, the purpose of this investigation was to evaluate the antimicrobial activity of two omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), using an in vitro multi-species subgingival biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of EPA and DHA extracts (100 µM) and the respective controls were assessed on 72 h biofilms by their submersion onto discs for 60 s. Antimicrobial activity was evaluated by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). ANOVA with Bonferroni correction was used to evaluate the antimicrobial activity of each of the fatty acids. Both DHA and EPA significantly reduced (p < 0.001 in all cases) the bacterial strains used in this biofilm model. The results with CLSM were consistent with those reported with qPCR. Structural damage was evidenced by SEM in some of the observed bacteria. It was concluded that both DHA and EPA have significant antimicrobial activity against the six bacterial species included in this biofilm model.}, } @article {pmid32937694, year = {2020}, author = {Su, JF and Wu, ZZ and Huang, TL and Zhang, H and Li, JW}, title = {A new technology for simultaneous calcium-nitrate and fluoride removal in the biofilm reactor.}, journal = {Journal of hazardous materials}, volume = {399}, number = {}, pages = {122846}, doi = {10.1016/j.jhazmat.2020.122846}, pmid = {32937694}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors ; Calcium ; *Denitrification ; Fluorides ; *Nitrates ; Nitrogen ; }, abstract = {In this study, a biofilm reactor containing Acinetobacter sp.H12 was established to investigate the simultaneous denitrification, the removal of calcium and fluoride performance. The main precipitation components in the reactor were determined by SEM, XPS and XRD. The effects of HRT (6 h, 9 h and 12 h), pH (6.0, 7.0, 8.0), influent F[-] concentration (3 mg/L, 5 mg/L, 10 mg/L) on synchronously removal of nitrate and F[-] and Ca[2+] during reactor operation were studied. Optimum operating conditions were achieved with a nitrate removal ratio of 100%, F[-] removal ratio of 81.91% and Ca[2+] removal ratio of 67.66%. Nitrogen was the main gaseous product analyzed by gas chromatography. Extracellular polymers (proteins) were also identified as sites for biological precipitation nucleation by fluorescence spectroscopy. Moreover, microbial distribution and community structure analysis showed that strain H12 was the dominat strain in the biofilm reactor. And combined with the performance prediction of the reactor, strain H12 played a major role in the process of simultaneous denitrification, F[-] and Ca[2+] removal.}, } @article {pmid32937249, year = {2020}, author = {Gilbertie, JM and Levent, G and Norman, KN and Vinasco, J and Scott, HM and Jacob, ME}, title = {Comprehensive phenotypic and genotypic characterization and comparison of virulence, biofilm, and antimicrobial resistance in urinary Escherichia coli isolated from canines.}, journal = {Veterinary microbiology}, volume = {249}, number = {}, pages = {108822}, doi = {10.1016/j.vetmic.2020.108822}, pmid = {32937249}, issn = {1873-2542}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Dog Diseases/*microbiology ; Dogs ; *Drug Resistance, Bacterial ; Escherichia coli Infections/microbiology/*veterinary ; Genotype ; Microbial Sensitivity Tests ; Urinary Tract Infections/microbiology/*veterinary ; Uropathogenic Escherichia coli/classification/*drug effects/*genetics ; Virulence Factors/genetics ; }, abstract = {Urinary tract infections (UTIs) affect nearly half of women and an estimated 14 % of the canine companion animal population at least once in their lifetime. As with humans, Escherichia coli is the most commonly isolated bacteria from canine UTIs and infections are dominated by specific phylogenetic groups with notable virulence attributes. In this study, we evaluated uropathogenic E. coli (UPEC) (n = 69) isolated from canine UTIs phenotypically and genotypically for virulence factors, biofilm formation and antimicrobial resistance profiles. Biofilm formation in UPEC strains was positively associated with common virulence factors including papG (p = 0.006), fimH (p < 0.0001), sfaS (p = 0.004), focA (p = 0.004), cnf-1 (p = 0.009) and hlyA (p = 0.006). There was a negative association between biofilm formation and phenotypic antimicrobial resistance for ampicillin (p < 0.0004), ciprofloxacin (p < 0.0001), and trimethoprim-sulfamethoxazole (p < 0.02), as well as multidrug resistance (isolates resistant to ≥ 3 classes of antimicrobials) (p < 0.0002), and the presence of extended spectrum beta-lactamase (ESBL)-producing genes (p < 0.05). In conclusion, UPECs isolated from clinical cases of canine UTIs show a broad negative association between antimicrobial resistance and biofilm formation, and this observation is supported both by phenotypic and genotypic endpoints. As the biofilm formation may result in antimicrobial tolerance, this could be a secondary evasive tactic of UPEC lacking traditional antimicrobial resistance traits. This observation is important for veterinary practitioners to consider when treating puzzling chronic intractable and/or recurrent cases of UTI that appear to be susceptible to antimicrobial therapy via traditional antimicrobial susceptibility testing (AST) methods.}, } @article {pmid32933329, year = {2021}, author = {Wakade, VS and Shende, P}, title = {Strategic advancements and multimodal applications of biofilm therapy.}, journal = {Expert opinion on biological therapy}, volume = {21}, number = {3}, pages = {395-412}, doi = {10.1080/14712598.2020.1822319}, pmid = {32933329}, issn = {1744-7682}, mesh = {Bacteria ; *Biofilms ; Humans ; *Quorum Sensing ; }, abstract = {INTRODUCTION: Biofilm is a layer of mucilage consisting of bacterial species like Escherichia coli and Streptococcus aureus adhering to the solid cell surface. Biofilm is an important and novel approach in a delivery system consisting of six elements that includes extracellular DNA, enzymes, proteins, bacteria, exopolysaccharides and water channels. The biofilm formation is based on two mechanisms: extra polymeric substance and quorum sensing. The microbes present in biofilm prevent direct interaction between the cell surface and foreign materials, like allergens, or toxic gases, like carbon-monoxide and chlorofluorocarbon, entering the body.

AREAS COVERED: The authors focus on the novel applications of biofilms such as adhesives, tissue engineering, targeted delivery system, probiotics, nutrients delivery, etc. Moreover, the information of the factors for biofilm formation, techniques useful in biofilm formation, and clinical studies are also covered in this article.

EXPERT OPINION: Many people believe that biofilms have a negative impact on human health, but the expert opinion states that biofilm is a futuristic approach useful in therapeutics for the treatment of tumors and cancer. Biofilms can be combined with novel delivery systems such as nanoparticles, microparticles, etc. for better therapeutic action.}, } @article {pmid32933157, year = {2020}, author = {Chen, H and Yang, Y and Weir, MD and Dai, Q and Lei, L and Homayounfar, N and Oates, TW and Yang, K and Zhang, K and Hu, T and Xu, HHK}, title = {Regulating Oral Biofilm from Cariogenic State to Non-Cariogenic State via Novel Combination of Bioactive Therapeutic Composite and Gene-Knockout.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32933157}, issn = {2076-2607}, support = {81771068//National Natural Science Foundation of China/ ; 2018JY0580//Applied Basic Research Program of Sichuan Province/ ; DFL20191501//Beijing Hospitals Authority Ascent Plan/ ; CFH2020-2-2142//Capital's Funds for Health Improvement and Research/ ; -//a seed grant from the University of Maryland Baltimore/ ; -//a bridge grant from the University of Maryland School of Dentistry/ ; }, abstract = {The objectives were to investigate a novel combination of gene-knockout with antimicrobial dimethylaminohexadecyl methacrylate (DMAHDM) composite in regulating oral biofilm from a cariogenic state toward a non-cariogenic state. A tri-species biofilm model included cariogenic Streptococcus mutans (S. mutans), and non-cariogenic Streptococcus sanguinis (S. sanguinis) and Streptococcus gordonii (S. gordonii). Biofilm colony-forming-units (CFUs), lactic acid and polysaccharide production were measured. TaqMan real-time-polymerase-chain reaction was used to determine the percentage of each species in biofilm. The rnc gene-knockout for S. mutans with DMAHDM composite reduced biofilm CFU by five logs, compared to control (p < 0.05). Using parent S. mutans, an overwhelming S. mutans percentage of 68.99% and 69.00% existed in biofilms on commercial composite and 0% DMAHDM composite, respectively. In sharp contrast, with a combination of S. mutans rnc knockout and DMAHDM composite, the cariogenic S. mutans percentage in biofilm was reduced to only 6.33%. Meanwhile, the non-cariogenic S. sanguinis + S. gordonii percentage was increased to 93.67%. Therefore, combining rnc-knockout with bioactive and therapeutic dental composite achieved the greatest reduction in S. mutans, and the greatest increase in non-cariogenic species, thereby yielding the least lactic acid-production. This novel method is promising to obtain wide applications to regulate biofilms and inhibit dental caries.}, } @article {pmid32933123, year = {2020}, author = {Usui, Y and Shimizu, T and Nakamura, A and Ito, M}, title = {Metabolites Produced by Kaistia sp. 32K Promote Biofilm Formation in Coculture with Methylobacterium sp. ME121.}, journal = {Biology}, volume = {9}, number = {9}, pages = {}, pmid = {32933123}, issn = {2079-7737}, support = {JP24117005//Ministry of Education, Culture, Sports, Science and Technology/ ; }, abstract = {Previously, we reported that the coculture of motile Methylobacterium sp. ME121 and non-motile Kaistia sp. 32K, isolated from the same soil sample, displayed accelerated motility of strain ME121 due to an extracellular polysaccharide (EPS) produced by strain 32K. Since EPS is a major component of biofilms, we aimed to investigate the biofilm formation in cocultures of the two strains. The extent of biofilm formation was measured by a microtiter dish assay with the dye crystal violet. A significant increase in the amount of biofilm was observed in the coculture of the two strains, as compared to that of the monocultures, which could be due to a metabolite produced by strain 32K. However, in the coculture with strain 32K, using Escherichia coli or Pseudomonas aeruginosa, there was no difference in the amount of biofilm formation as compared with the monoculture. Elevated biofilm formation was also observed in the coculture of strain ME121 with Kaistia adipata, which was isolated from a different soil sample. Methylobacterium radiotolerans, isolated from another soil sample, showed a significant increase in biofilm formation when cocultured with K. adipata, but not with strain 32K. We also found that the culture supernatants of strains 32K and K. adipata accelerated the motility of strains ME121 and M. radiotolerans, wherein culture supernatant of K. adipata significantly increased the motility of M. radiotolerans, as compared to that by the culture supernatant of strain 32K. These results indicated that there was a positive relationship between accelerated motility and increased biofilm formation in Methylobacterium spp. This is the first study to report that the metabolites from Kaistia spp. could specifically modulate the biofilm-forming ability of Methylobacterium spp. Methylobacterium spp. biofilms are capable of inhibiting the biofilm formation of mycobacteria, which are opportunistic pathogens that cause problems in infectious diseases. Thus, the metabolites from the culture supernatant of Kaistia spp. have the potential to contribute to the environment in which increased biofilm production of Methylobacterium is desired.}, } @article {pmid32932750, year = {2020}, author = {Mongaret, C and Varin-Simon, J and Lamret, F and El-Mahdy, TS and Brasme, L and Vernet-Garnier, V and Gangloff, SC and Ohl, X and Reffuveille, F}, title = {Cutibacterium acnes Biofilm Study during Bone Cells Interaction.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32932750}, issn = {2076-2607}, abstract = {Cutibacterium acnes is an opportunistic pathogen involved in Bone and Prosthesis Infections (BPIs). In this study, we observed the behavior of commensal and BPI C. acnes strains in the bone environment through bacterial internalization by osteoblast-like cells and biofilm formation. For the commensal strains, less than 1% of the bacteria were internalized; among them, about 32.7 ± 3.9% persisted intracellularly for up to 48 h. C. acnes infection seems to have no cytotoxic effect on bone cells as detected by LDH assay. Interestingly, commensal C. acnes showed a significant increase in biofilm formation after osteoblast-like internalization for 50% of the strains (2.8-fold increase). This phenomenon is exacerbated on a titanium support, a material used for medical devices. For the BPI clinical strains, we did not notice any increase in biofilm formation after internalization despite a similar internalization rate by the osteoblast-like cells. Furthermore, fluorescent staining revealed more live bacteria within the biofilm after osteoblast-like cell interaction, for all strains (BPIs and commensal). The genomic study did not reveal any link between their clinical origin and phylotype. In conclusion, we have shown for the first time the possible influence of internalization by osteoblast-like cells on commensal C. acnes.}, } @article {pmid32932628, year = {2020}, author = {Schestakow, A and Hannig, M}, title = {Effects of Experimental Agents Containing Tannic Acid or Chitosan on the Bacterial Biofilm Formation in Situ.}, journal = {Biomolecules}, volume = {10}, number = {9}, pages = {}, pmid = {32932628}, issn = {2218-273X}, mesh = {Adult ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cattle ; Chitosan/*pharmacology ; Chlorhexidine/pharmacology ; Dental Enamel/drug effects/microbiology ; Humans ; Hydrochloric Acid/pharmacology ; Hydrogen-Ion Concentration ; Periodontal Splints/microbiology ; Tannins/*pharmacology ; }, abstract = {Chitosan and tannic acid are known for their antibacterial properties. In the present in-situ study, their antibacterial and anti-adherent effects on biofilm formation on enamel were investigated. Six subjects carried upper jaw splints with bovine enamel specimens, allowing in-situ biofilm formation. During the two-day trial, subjects rinsed with experimental solutions that contained either chitosan, tannic acid (pH = 2.5), tannic acid (pH = 7) or hydrochloric acid. Water served as the negative and chlorhexidine as the positive control. Rinsing occurred four or five times following two different rinsing protocols to investigate both the immediate and long-lasting effects. After 48 h of intraoral exposure, the dental plaque was stained with LIVE/DEAD[®] BacLight, and fluorescence micrographs were evaluated by using the software ImageJ. The results were verified by scanning electron microscopy. Rinsing with chitosan resulted in little immediate antibacterial and anti-adherent effects but failed to show any long-lasting effect, while rinsing with tannic acid resulted in strong immediate and long-lasting effects. Except for a slightly lower antibacterial effect, the neutral solution of tannic acid was as good as the acidic solution. Hydrochloric acid showed neither an antibacterial nor an anti-adherent effect on dental biofilm formation. Experimental solutions containing tannic acid are promising anti-biofilm agents, irrespective of the pH values of the solutions. Chitosan, on the other hand, was not able to prevent biofilm formation.}, } @article {pmid32932117, year = {2020}, author = {Tang, Q and Sheng, Y and Li, C and Wang, W and Liu, X}, title = {Simultaneous removal of nitrate and sulfate using an up-flow three-dimensional biofilm electrode reactor: Performance and microbial response.}, journal = {Bioresource technology}, volume = {318}, number = {}, pages = {124096}, doi = {10.1016/j.biortech.2020.124096}, pmid = {32932117}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Denitrification ; Electrodes ; *Nitrates ; Sulfates ; }, abstract = {Nitrate removal from low carbon water is a problem in the water treatment, especially in the presence of high sulfate. In this work, an up-flow three-dimensional biofilm electrode reactor (3D-BER) was established to remove nitrate and sulfate from low organic carbon water. Results indicated that sulfate negatively affected nitrate removal. Moreover, high electric current and short hydraulic retention time deteriorated the performance of nitrate and sulfate removal. When the influent of SO4[2-] was 150 mg/L, the removal efficiency of NO3[-]-N and SO4[2-] was 88.49 ± 4.5% and 29.35 ± 5.5%, respectively. The high-throughput sequencing revealed that denitrifying bacteria dominated in the lower part of the reactor while sulfate reducing bacteria dominated in the upper part of the reactor. It was speculated that oxidation products of sulfide could serve as supplementary electron donors to enhance nitrate removal in the 3D-BER.}, } @article {pmid32930658, year = {2020}, author = {Vijayakumar, K and Manigandan, V and Jeyapragash, D and Bharathidasan, V and Anandharaj, B and Sathya, M}, title = {Eucalyptol inhibits biofilm formation of Streptococcus pyogenes and its mediated virulence factors.}, journal = {Journal of medical microbiology}, volume = {69}, number = {11}, pages = {1308-1318}, doi = {10.1099/jmm.0.001253}, pmid = {32930658}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Eucalyptol/*pharmacology ; Gene Expression ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Streptococcus pyogenes/*drug effects/*genetics/pathogenicity ; Virulence ; Virulence Factors/*genetics ; }, abstract = {Introduction. Streptococcus pyogenes is a diverse virulent synthesis pathogen responsible for invasive systemic infections. Establishment of antibiotic resistance in the pathogen has produced a need for new antibiofilm agents to control the biofilm formation and reduce biofilm-associated resistance development.Aim. The present study investigates the in vitro antibiofilm activity of eucalyptol against S. pyogenes.Methodology. The antibiofilm potential of eucalyptol was assessed using a microdilution method and their biofilm inhibition efficacy was visualized by microscopic analysis. The biochemical assays were performed to assess the influence of eucalyptol on virulence productions. Real-time PCR analysis was performed to evaluate the expression profile of the virulence genes.Results. Eucalyptol showed significant antibiofilm potential in a dose-dependent manner without affecting bacterial growth. Eucalyptol at 300 µg ml[-1] (biofilm inhibitory concentration) significantly inhibited the initial stage of biofilm formation in S. pyogenes. However, eucalyptol failed to diminish the mature biofilms of S. pyogenes at biofilm inhibitory concentration and it effectively reduced the biofilm formation on stainless steel, titanium, and silicone surfaces. The biochemical assay results revealed that eucalyptol greatly affects the cell-surface hydrophobicity, auto-aggregation, extracellular protease, haemolysis and hyaluronic acid synthesis. Further, the gene-expression analysis results showed significant downregulation of virulence gene expression upon eucalyptol treatment.Conclusion. The present study suggests that eucalyptol applies its antibiofilm assets by intruding the initial biofilm formation of S. pyogenes. Supplementary studies are needed to understand the mode of action involved in biofilm inhibition.}, } @article {pmid32929332, year = {2020}, author = {Zhang, Y and Pi, Y and Hua, Y and Xie, J and Wang, C and Guo, K and Zhao, Z and Yong, Y}, title = {Bacteria responsive polyoxometalates nanocluster strategy to regulate biofilm microenvironments for enhanced synergetic antibiofilm activity and wound healing.}, journal = {Theranostics}, volume = {10}, number = {22}, pages = {10031-10045}, pmid = {32929332}, issn = {1838-7640}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/metabolism ; Biofilms/*drug effects ; Cellular Microenvironment/*drug effects ; Female ; Hydrogen Peroxide/metabolism ; Mice ; Mice, Inbred BALB C ; Nanoparticles/*administration & dosage/chemistry ; Peroxidase/metabolism ; Reactive Oxygen Species/metabolism ; Tungsten Compounds/*pharmacology ; Wound Healing/*drug effects ; }, abstract = {Backgroud: Nowadays, biofilms that are generated as a result of antibiotic abuse cause serious threats to global public health. Such films are the primary factor that contributes to the failure of antimicrobial treatment. This is due to the fact that the films prevent antibiotic infiltration, escape from innate immune attacks by phagocytes and consequently generate bacterial resistance. Therefore, exploiting novel antibacterial agents or strategies is extremely urgent. Methods: Herein, we report a rational construction of a novel biofilm microenvironment (BME)-responsive antibacterial platform that is based on tungsten (W)-polyoxometalate clusters (POMs) to achieve efficient bactericidal effects. Results: On one hand, the acidity and reducibility of a BME could lead to the self-assembly of POMs to produce large aggregates, which favor biofilm accumulation and enhance photothermal conversion under near-infrared (NIR) light irradiation. On the other hand, reduced POM aggregates with BME-induced photothermal-enhanced efficiency also exhibit surprisingly high peroxidase-like activity in the catalysis of bacterial endogenous hydrogen peroxide (H2O2) to produce abundant reactive oxygen species (ROS). This enhances biofilm elimination and favors antibacterial effects. Most importantly, reduced POMs exhibit the optimal peroxidase-like activity in an acidic BME. Conclusion: Therefore, in addition to providing a prospective antibacterial agent, intelligent acid/reductive dual-responsive POMs will establish a new representative paradigm for the areas of healthcare with minimal side effects.}, } @article {pmid32928929, year = {2020}, author = {Slipski, CJ and Jamieson, TR and Zhanel, GG and Bay, DC}, title = {Riboswitch-Associated Guanidinium-Selective Efflux Pumps Frequently Transmitted on Proteobacterial Plasmids Increase Escherichia coli Biofilm Tolerance to Disinfectants.}, journal = {Journal of bacteriology}, volume = {202}, number = {23}, pages = {}, pmid = {32928929}, issn = {1098-5530}, mesh = {Biofilms/*drug effects ; Disinfectants/*pharmacology ; Drug Resistance, Bacterial/drug effects ; Escherichia coli/*drug effects/genetics/physiology ; Escherichia coli Proteins/genetics/metabolism ; Guanidine/*metabolism ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Plasmids/*genetics/metabolism ; Proteobacteria/*genetics ; Quaternary Ammonium Compounds/*pharmacology ; Riboswitch/*drug effects ; }, abstract = {Members of the small multidrug resistance (SMR) efflux pump family known as SugE (recently renamed Gdx) are known for their narrow substrate selectivity to small guanidinium (Gdm[+]) compounds and disinfectant quaternary ammonium compounds (QACs). Gdx members have been identified on multidrug resistance plasmids in Gram-negative bacilli, but their functional role remains unclear, as few have been characterized. Here, we conducted a survey of sequenced proteobacterial plasmids that encoded one or more SugE/Gdx sequences in an effort to (i) identify the most frequently represented Gdx member(s) on these plasmids and their sequence diversity, (ii) verify if Gdx sequences possess a Gdm[+] riboswitch that regulates their translation similarly to chromosomally encoded Gdx members, and (iii) determine the antimicrobial susceptibility profile of the most predominate Gdx member to various QACs and antibiotics in Escherichia coli strains BW25113 and KAM32. The results of this study determined 14 unique SugE sequences, but only one Gdx sequence, annotated as "SugE(p)," predominated among the >140 plasmids we surveyed. Enterobacterales plasmids carrying sugE(p) possessed a guanidine II riboswitch similar to the upstream region of E. coligdx Cloning and expression of sugE(p), gdx, and emrE sequences into a low-copy-number expression vector (pMS119EH) revealed significant increases in QAC resistance to a limited range of detergent-like QACs only when gdx and sugE(p) transformants were grown as biofilms. These findings suggest that sugE(p) presence on proteobacterial plasmids may be driven by species that frequently encounter Gdm[+] and QAC exposure.IMPORTANCE This study characterized the function of antimicrobial-resistant phenotypes attributed to plasmid-encoded guanidinium-selective small multidrug resistance (Gdm/SugE) efflux pumps. These sequences are frequently monitored as biocide resistance markers in antimicrobial resistance surveillance studies. Our findings reveal that enterobacterial gdm sequences transmitted on plasmids possess a guanidine II riboswitch, which restricts transcript translation in the presence of guanidinium. Cloning and overexpression of this gdm sequence revealed that it confers higher resistance to quaternary ammonium compound (QAC) disinfectants (which possess guanidium moieties) when grown as biofilms. Since biofilms are commonly eradicated with QAC-containing compounds, the presence of this gene on plasmids and its biofilm-specific resistance are a growing concern for clinical and food safety prevention measures.}, } @article {pmid32927675, year = {2020}, author = {Leão, C and Borges, A and Simões, M}, title = {NSAIDs as a Drug Repurposing Strategy for Biofilm Control.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32927675}, issn = {2079-6382}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {Persistent infections, usually associated with biofilm-producing bacteria, are challenging for both medical and scientific communities. The potential interest in drug repurposing for biofilm control is growing due to both disinvestment in antibiotic R&D and reduced efficacy of the available panel of antibiotics. In the present study, the antibacterial and antibiofilm activities of four non-steroidal anti-inflammatory drugs (NSAIDs), piroxicam (PXC), diclofenac sodium (DCF), acetylsalicylic acid (ASA) and naproxen sodium (NPX) were evaluated against Escherichia coli and Staphylococcus aureus. The minimum inhibitory/bactericidal concentrations (MICs and MBCs) and the dose-response curves from exposure to the selected NSAIDs were determined. MICs were found for PXC (800 μg/mL) and ASA (1750 μg/mL) against E. coli, and for DCF (2000 μg/mL) and ASA (2000 μg/mL) against S. aureus. No MBCs were found (>2000 μg/mL). The potential of NSAIDs to eradicate preformed biofilms was characterized in terms of biofilm mass, metabolic activity and cell culturability. Additionally, the NSAIDs were tested in combination with kanamycin (KAN) and tetracycline (TET). ASA, DCF and PXC promoted significant reductions in metabolic activity and culturability. However, only PXC promoted biofilm mass removal. Additive interactions were obtained for most of the combinations between NSAIDs and KAN or TET. In general, NSAIDs appear to be a promising strategy to control biofilms as they demonstrated to be more effective than conventional antibiotics.}, } @article {pmid32927027, year = {2020}, author = {Rasapalli, S and Murphy, ZF and Sammeta, VR and Golen, JA and Weig, AW and Melander, RJ and Melander, C and Macha, P and Vasudev, MC}, title = {Synthesis and biofilm inhibition studies of 2-(2-amino-6-arylpyrimidin-4-yl)quinazolin-4(3H)-ones.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {30}, number = {23}, pages = {127550}, pmid = {32927027}, issn = {1464-3405}, support = {R01 DE022350/DE/NIDCR NIH HHS/United States ; }, mesh = {Acinetobacter baumannii/drug effects/physiology ; Anti-Bacterial Agents/chemical synthesis/*pharmacology/toxicity ; Biofilms/*drug effects ; Cell Line ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Microbial Sensitivity Tests ; Molecular Structure ; Pyrimidines/chemical synthesis/*pharmacology/toxicity ; Quinazolinones/chemical synthesis/*pharmacology/toxicity ; Structure-Activity Relationship ; }, abstract = {Synthesis of novel 4(3H)-quinazolinonyl aminopyrimidine derivatives has been achieved via quinazolinonyl enones which in turn were obtained from 2-acyl-4(3H)-quinazolinone. They have been assayed for biofilm inhibition against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative bacteria (Acinetobacter baumannii). The analogues with 2,4,6-trimethoxy phenyl, 4-methylthio phenyl, and 3-bromo phenyl substituents (5h, 5j & 5k) have been shown to inhibit biofilm formation efficiently in MRSA with IC50 values of 20.7-22.4 μM). The analogues 5h and 5j have demonstrated low toxicity in human cells in vitro and can be investigated further as leads.}, } @article {pmid32926768, year = {2020}, author = {Chitrakar, I and Iuliano, JN and He, Y and Woroniecka, HA and Tolentino Collado, J and Wint, JM and Walker, SG and Tonge, PJ and French, JB}, title = {Structural Basis for the Regulation of Biofilm Formation and Iron Uptake in A. baumannii by the Blue-Light-Using Photoreceptor, BlsA.}, journal = {ACS infectious diseases}, volume = {6}, number = {10}, pages = {2592-2603}, pmid = {32926768}, issn = {2373-8227}, support = {R25 GM103962/GM/NIGMS NIH HHS/United States ; T32 GM092714/GM/NIGMS NIH HHS/United States ; }, mesh = {*Acinetobacter baumannii ; Bacterial Proteins/genetics ; Biofilms ; Humans ; Iron ; Light ; }, abstract = {The opportunistic human pathogen, A. baumannii, senses and responds to light using the blue light sensing A (BlsA) photoreceptor protein. BlsA is a blue-light-using flavin adenine dinucleotide (BLUF) protein that is known to regulate a wide variety of cellular functions through interactions with different binding partners. Using immunoprecipitation of tagged BlsA in A. baumannii lysates, we observed a number of proteins that interact with BlsA, including several transcription factors. In addition to a known binding partner, the iron uptake regulator Fur, we identified the biofilm response regulator BfmR as a putative BlsA-binding partner. Using microscale thermophoresis, we determined that both BfmR and Fur bind to BlsA with nanomolar binding constants. To better understand how BlsA interacts with and regulates these transcription factors, we solved the X-ray crystal structures of BlsA in both a ground (dark) state and a photoactivated light state. Comparison of the light- and dark-state structures revealed that, upon photoactivation, the two α-helices comprising the variable domain of BlsA undergo a distinct conformational change. The flavin-binding site, however, remains largely unchanged from dark to light. These structures, along with docking studies of BlsA and Fur, reveal key mechanistic details about how BlsA propagates the photoactivation signal between protein domains and on to its binding partner. Taken together, our structural and biophysical data provide important insights into how BlsA controls signal transduction in A. baumannii and provides a likely mechanism for blue-light-dependent modulation of biofilm formation and iron uptake.}, } @article {pmid32925997, year = {2020}, author = {Aleksandrowicz, P and Brzezińska-Błaszczyk, E and Dudko, A and Agier, J}, title = {Archaea Occurrence in the Subgingival Biofilm in Patients with Peri-implantitis and Periodontitis.}, journal = {The International journal of periodontics & restorative dentistry}, volume = {40}, number = {5}, pages = {677-683}, doi = {10.11607/prd.4670}, pmid = {32925997}, issn = {1945-3388}, mesh = {Archaea ; Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis ; *Periodontitis ; RNA, Ribosomal, 16S ; }, abstract = {This study aimed to determine the prevalence and diversity of archaea and select bacteria in the subgingival biofilm of patients with peri-implantitis in comparison to patients with unaffected implants and patients with periodontitis. Samples of subgingival biofilm from oral sites were collected for DNA extraction (n = 139). A 16S rRNA gene-based polymerase chain reaction assay was used to determine the presence of archaea and select bacteria. Seven samples were selected for direct sequencing. Archaea were detected in 10% of samples from peri-implantitis sites, but not in samples from the unaffected dental implant. Archaea were present in 53% and 64% of samples from mild and moderate/advanced periodontitis sites, respectively. The main representative of the Archaea domain found in biofilm from periodontitis and peri-implantitis sites was Methanobrevibacter oralis. The present results revealed that archaea are present in diseased but not healthy implants. It was also found that archaea were more abundant in periodontitis than in peri-implantitis sites. Hence, the potential role of archaea in peri-implantitis and periodontitis should be taken into consideration.}, } @article {pmid32924479, year = {2020}, author = {Meiers, J and Zahorska, E and Röhrig, T and Hauck, D and Wagner, S and Titz, A}, title = {Directing Drugs to Bugs: Antibiotic-Carbohydrate Conjugates Targeting Biofilm-Associated Lectins of Pseudomonas aeruginosa.}, journal = {Journal of medicinal chemistry}, volume = {63}, number = {20}, pages = {11707-11724}, pmid = {32924479}, issn = {1520-4804}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Carbohydrates/chemistry/*pharmacology ; Cell Line, Tumor ; Ciprofloxacin/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; HEK293 Cells ; Humans ; Lectins/*antagonists & inhibitors/metabolism ; Molecular Structure ; Pseudomonas aeruginosa/*drug effects/metabolism ; Structure-Activity Relationship ; }, abstract = {Chronic infections by Pseudomonas aeruginosa are characterized by biofilm formation, which effectively enhances resistance toward antibiotics. Biofilm-specific antibiotic delivery could locally increase drug concentration to break antimicrobial resistance and reduce the drug's peripheral side effects. Two extracellular P. aeruginosa lectins, LecA and LecB, are essential structural components for biofilm formation and thus render a possible anchor for biofilm-targeted drug delivery. The standard-of-care drug ciprofloxacin suffers from severe systemic side effects and was therefore chosen for this approach. We synthesized several ciprofloxacin-carbohydrate conjugates and established a structure-activity relationship. Conjugation of ciprofloxacin to lectin probes enabled biofilm accumulation in vitro, reduced the antibiotic's cytotoxicity, but also reduced its antibiotic activity against planktonic cells due to a reduced cell permeability and on target activity. This work defines the starting point for new biofilm/lectin-targeted drugs to modulate antibiotic properties and ultimately break antimicrobial resistance.}, } @article {pmid32924224, year = {2021}, author = {Abdalla, MM and Ali, IAA and Khan, K and Mattheos, N and Murbay, S and Matinlinna, JP and Neelakantan, P}, title = {The Influence of Surface Roughening and Polishing on Microbial Biofilm Development on Different Ceramic Materials.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {30}, number = {5}, pages = {447-453}, doi = {10.1111/jopr.13260}, pmid = {32924224}, issn = {1532-849X}, mesh = {Biofilms ; Ceramics ; *Computer-Aided Design ; *Dental Porcelain ; Materials Testing ; Poland ; Surface Properties ; }, abstract = {PURPOSE: To test the hypothesis that surface roughening and polishing of ceramics have no effect on their surface roughness and biofilm adhesion.

MATERIALS AND METHODS: Feldspathic ceramic Vitablocks™ TriLuxe forte (VTF), lithium disilicate glass IPS e.max Press™ (IPS) and zirconia reinforced lithium silicate Vita Suprinity™ (VS) ceramic blocks (n = 27 per group) were prepared from sintered CAD blocks using a water-cooled saw. They were further subdivided into 3 subgroups according to the surface treatment protocols (n = 9): as prepared, roughened and polished. The surface roughness of the ceramic blocks was measured using an electro-mechanical profilometer. The ceramic sections were inoculated with Streptococcus mutans and incubated for 48 hours to form a biofilm. The ceramic surfaces with the biofilms were analyzed using Confocal Laser Scanning Microscopy to calculate the percentage of live bacteria and substratum coverage by the biofilm, and further visualized using scanning electron microscopy. Statistical analysis was done with SPSS software using two-way ANOVA, followed by post hoc Bonferroni test to identify significant differences between the groups. The level of significance was set at p = 0.05.

RESULTS: As prepared VTF showed significantly higher mean surface roughness values than as prepared IPS and VS. The mean percentage of live bacteria and biofilm coverage of the substrate were significantly higher in the roughened ceramic blocks than the as prepared and polished blocks for all three ceramic types (p < 0.05). Polished specimens of VS significantly lower percentage of biofilm coverage than the other groups (p < 0.05).

CONCLUSIONS: This study sheds new light that adjustments of ceramic restorations prior to cementation increases the likelihood for formation and adhesion of microbial biofilms on the surface. Polished zirconia reinforced lithium disilicate ceramics demonstrated the lowest bacterial adhesion among the evaluated ceramics.}, } @article {pmid32923486, year = {2020}, author = {Cholo, MC and Rasehlo, SSM and Venter, E and Venter, C and Anderson, R}, title = {Effects of Cigarette Smoke Condensate on Growth and Biofilm Formation by Mycobacterium tuberculosis.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {8237402}, pmid = {32923486}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Catalase/metabolism ; Cigarette Smoking/*adverse effects ; Culture Media/metabolism ; Mycobacterium tuberculosis/*drug effects ; Oxidative Stress/drug effects ; Plankton/drug effects ; Reactive Oxygen Species/metabolism ; Tobacco/*adverse effects ; }, abstract = {MATERIALS AND METHODS: The planktonic and biofilm-forming cultures were prepared in Middlebrook 7H9 and Sauton broth media, respectively, using Mtb strain, H37Rv. The effects of CSC at concentrations of 0.05-3.12 mg/L on growth, biofilm formation and structure were evaluated using microplate Alamar Blue assay, spectrophotometric procedure and scanning electron microscopy (SEM), respectively. Involvement of reactive oxygen species in CSC-mediated biofilm formation was investigated by including catalase in biofilm-forming cultures.

RESULTS: CSC did not affect the growth of planktonic bacteria, but rather led to a statistically significant increase in biofilm formation at concentrations of 0.4-3.12 mg/L, as well as in the viability of biofilm-forming bacteria at CSC concentrations of 0.2-1.56 mg/L. SEM confirmed an agglomerated biofilm matrix and irregular bacterial morphology in CSC-treated biofilms. Inclusion of catalase caused significant attenuation of CSC-mediated augmentation of biofilm formation by Mtb, implying involvement of oxidative stress. These findings demonstrate that exposure of Mtb to CSC resulted in increased biofilm formation that appeared to be mediated, at least in part, by oxidative stress, while no effect on planktonic cultures was observed.

CONCLUSION: Smoking-related augmentation of biofilm formation by Mtb may contribute to persistence of the pathogen, predisposing to disease reactivation and counteracting the efficacy of antimicrobial chemotherapy.}, } @article {pmid32923408, year = {2020}, author = {Wasfi, R and Hamed, SM and Amer, MA and Fahmy, LI}, title = {Proteus mirabilis Biofilm: Development and Therapeutic Strategies.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {414}, pmid = {32923408}, issn = {2235-2988}, mesh = {Biofilms ; Humans ; *Proteus mirabilis ; Quorum Sensing ; Urease ; *Urinary Tract Infections/drug therapy ; }, abstract = {Proteus mirabilis is a Gram negative bacterium that is a frequent cause of catheter-associated urinary tract infections (CAUTIs). Its ability to cause such infections is mostly related to the formation of biofilms on catheter surfaces. In order to form biofilms, P. mirabilis expresses a number of virulence factors. Such factors may include adhesion proteins, quorum sensing molecules, lipopolysaccharides, efflux pumps, and urease enzyme. A unique feature of P. mirabilis biofilms that build up on catheter surfaces is their crystalline nature owing to their ureolytic biomineralization. This leads to catheter encrustation and blockage and, in most cases, is accompanied by urine retention and ascending UTIs. Bacteria embedded in crystalline biofilms become highly resistant to conventional antimicrobials as well as the immune system. Being refractory to antimicrobial treatment, alternative approaches for eradicating P. mirabilis biofilms have been sought by many studies. The current review focuses on the mechanism by which P. mirabilis biofilms are formed, and a state of the art update on preventing biofilm formation and reduction of mature biofilms. These treatment approaches include natural, and synthetic compounds targeting virulence factors and quorum sensing, beside other strategies that include carrier-mediated diffusion of antimicrobials into biofilm matrix. Bacteriophage therapy has also shown successful results in vitro for combating P. mirabilis biofilms either merely through their lytic effect or by acting as facilitators for antimicrobials diffusion.}, } @article {pmid32921470, year = {2020}, author = {Verma, P and Anand, S}, title = {Antimicrobial activity as a potential factor influencing the predominance of Bacillus subtilis within the constitutive microflora of a whey reverse osmosis membrane biofilm.}, journal = {Journal of dairy science}, volume = {103}, number = {11}, pages = {9992-10000}, doi = {10.3168/jds.2020-18576}, pmid = {32921470}, issn = {1525-3198}, mesh = {Acinetobacter/growth & development/isolation & purification ; Anti-Infective Agents/isolation & purification/*pharmacology ; Bacillus licheniformis/growth & development/isolation & purification ; Bacillus subtilis/*chemistry/growth & development/isolation & purification/physiology ; Biofilms/drug effects/*growth & development ; Caseins ; Micropore Filters/microbiology ; Osmosis ; Protein Hydrolysates ; Whey/*microbiology ; }, abstract = {Current cleaning and sanitation protocols may not be adequately effective in cleaning separation membranes and can result in the formation of resilient multispecies biofilms. The matured biofilms may result in a bacterial predominance with resilient strains on membranes with a prolonged use. In our previous study, we isolated organisms such as Bacillus subtilis, Bacillus licheniformis, Exiguobacterium aurantiacum, and Acinetobacter radioresistens from an 18-mo-old reverse osmosis membrane. The competitive exclusion studies revealed the predominance of B. subtilis within the membrane biofilm microflora. This study investigated the antimicrobial activity of the B. subtilis isolate as a potential cause of its predominance. The culture isolate was propagated in tryptic soy broth at 37°C, and microfiltered to prepare cell-free extracts (CFE) at 8-, 10-, 12-, 14-, 16-, and 18-h intervals. The CFE were freeze-dried and suspended in minimum quantities of HPLC-grade water to prepare concentrated solutions. The antimicrobial activities of CFE were tested using the agar-well assay against the biofilm constitutive microflora. The experiments were conducted in triplicates and means were compared for significant differences using a general linear mixed model procedure. The results indicated the highest antimicrobial activity of 12-h CFE of B. subtilis against other constitutive microflora such as Exiguobacterium sp., E. auranticum, and A. radioresistens, with average inhibition zone sizes of 16.5 ± 0.00, 16.25 ± 0.66, and 20.6 ± 0.00 mm, respectively. Upon treatment with proteinase K, the CFE completely lost its antimicrobial activity, establishing it to be a proteinaceous compound. The AA profiling revealed the total crude protein in CFE to be 51% (wt/wt), with its major constituent as glutamic acid (11.30% wt/wt). The freeze-dried CFE was thermally stable on exposure to the common temperature used for sanitizer applications (23.8°C for 5 and 10 min) and over a pH range of 3.0 to 6.3. The study helped us understand the role of the antimicrobial compound produced by B. subtilis as a potential cause of its predominance within the biofilm constitutive microflora.}, } @article {pmid32921268, year = {2021}, author = {Kaur, T and Putatunda, C and Vyas, A and Kumar, G}, title = {Zinc oxide nanoparticles inhibit bacterial biofilm formation via altering cell membrane permeability.}, journal = {Preparative biochemistry & biotechnology}, volume = {51}, number = {4}, pages = {309-319}, doi = {10.1080/10826068.2020.1815057}, pmid = {32921268}, issn = {1532-2297}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Bacillus cereus/drug effects ; Biofilms/*drug effects ; Cell Membrane Permeability/*drug effects ; Escherichia coli/drug effects ; Green Chemistry Technology/methods ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Particle Size ; Phyllanthus emblica/*chemistry ; Plant Extracts/chemistry ; Pseudomonas aeruginosa/drug effects ; Spectroscopy, Fourier Transform Infrared ; Streptococcus pyogenes/drug effects ; X-Ray Diffraction ; Zinc Oxide/*chemistry/*pharmacology ; }, abstract = {In the current scenario nanoparticles (NPs) have gained a breathtaking impetus due to their multidimensional applications in varied fields. In the present effort, biogenic synthesis of Zinc Oxide nanoparticles (ZnO NPs) was carried out using aqueous extract of dried powder of Emblica officinalis (Amla). Physicochemical characterization of nanoparticles was carried out via UV-Visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) wherein the particles were found to be quasi spherical and with a size ranging between 3 and 11 nm. The ZnO nanoparticles exhibited significant antibacterial activity against bacteria as Streptococcus pyogenes MTCC 442, Bacillus cereus MTCC 1272, Escherichia coli MTCC 1687 and Pseudomonas aeruginosa MTCC 4673. The nanoparticles displayed high anti-biofilm activity toward all the bacterial strains, when tested against three different base materials viz. glass, plastic and metal (Aluminum). Further, the nanoparticle treatment of bacterial cells caused changes in their cell membrane permeability, leading to leakage of nucleic acid from the bacterial cells, thereby defining it as the most probable mechanism for their anti-biofilm potential.}, } @article {pmid32920147, year = {2020}, author = {Ali, IAA and Cheung, BPK and Matinlinna, J and Lévesque, CM and Neelakantan, P}, title = {Trans-cinnamaldehyde potently kills Enterococcus faecalis biofilm cells and prevents biofilm recovery.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104482}, doi = {10.1016/j.micpath.2020.104482}, pmid = {32920147}, issn = {1096-1208}, mesh = {Acrolein/analogs & derivatives ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Enterococcus faecalis ; *Root Canal Irrigants ; Sodium Hypochlorite ; }, abstract = {Enterococcus faecalis is a biofilm-forming, nosocomial pathogen that is frequently isolated from failed root canal treatments. Contemporary root canal disinfectants are ineffective in eliminating these biofilms and preventing reinfection. As a result, there is a pressing need to identify novel and safe antibiofilm molecules. The effect of short-term (5 and 15 min) and long-term (24 h) treatments of trans-cinnamaldehyde (TC) on the viability of E. faecalis biofilms was compared with currently used root canal disinfectants. Treatment for 15 min with TC reduced biofilm metabolic activity as effective as 1% sodium hypochlorite and 2% chlorhexidine. Treatment with TC for 24 h was significantly more effective than 2% chlorhexidine in reducing the viable cell counts of biofilms. This serendipitous effect of TC was sustained for 10 days under growth-favoring conditions. For the first time, our study highlights the strong antibacterial activity of TC against E. faecalis biofilms, and notably, its ability to prevent biofilm recovery after treatment.}, } @article {pmid32920078, year = {2020}, author = {Han, H and Gao, Y and Chai, M and Zhang, X and Liu, S and Huang, Y and Jin, Q and Grzybowski, A and Ji, J and Yao, K}, title = {Biofilm microenvironment activated supramolecular nanoparticles for enhanced photodynamic therapy of bacterial keratitis.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {327}, number = {}, pages = {676-687}, doi = {10.1016/j.jconrel.2020.09.014}, pmid = {32920078}, issn = {1873-4995}, mesh = {Biofilms ; Humans ; *Keratitis/drug therapy ; *Nanoparticles ; *Photochemotherapy ; Pseudomonas aeruginosa ; }, abstract = {Infectious keratitis caused by bacterial biofilms is one of the main causes of corneal blindness, presenting a serious threat to public health. In this study, matrix metalloproteinase (MMP)-sensitive supramolecular nanoparticles (denoted as MMP-S NPs) were constructed for enhancing photodynamic antibacterial effect against biofilm-associated bacterial keratitis. MMP-S NPs were prepared by host-guest self-assembly of chlorin e6 (Ce6) conjugated β-cyclodextrin (β-CD) prodrug (β-CD-Ce6) and MMP-9-sensitive peptides (YGRKKKRRQRRR-GPLGVRG-EEEEEE) terminated with adamantane (Ad) (Ad-MMP-S PEPs). MMP-S NPs with EEEEEE peptide shell had a negatively charged surface, preventing adhesion to the normal ocular surface or healthy corneal cells, thus enhancing tear retention time. After arriving at the infected lesions, the protective EEEEEE peptide shell of MMP-S NPs was removed, triggered by overexpressed MMP-9 in the keratitis microenvironment. The subsequently exposed cationic peptides helped the nanoparticles penetrate and accumulate in biofilms as well as bind to Gram-negative bacteria Pseudomonas aeruginosa (P. aeruginosa), which eventually improved the photodynamic antibacterial effect. Furthermore, the P. aeruginosa keratitis model verified the high effectiveness of a topical eye drop formulation of MMP-S NPs in killing bacteria by destroying the bacterial membrane as a result of in situ photodynamic activation of reactive oxygen species (ROS) formation under light irradiation. Moreover, the inflammatory response in the cornea was inhibited to a great extent. As a result, further damage to the corneal tissue was completely suppressed. This research provides a viable antibacterial alternative to fight against bacterial keratitis through effective elimination of infectious bacteria and eradication of bacterial biofilms in the cornea.}, } @article {pmid32918643, year = {2020}, author = {Kavita, S and Pooranachithra, M and Singh, N and Prasanth, MI and Balamurugan, K and Goel, G}, title = {Lactobacillus gastricus BTM 7 prevents intestinal colonization by biofilm forming Cronobacter sakazakii in Caenorhabditis elegans model host.}, journal = {Antonie van Leeuwenhoek}, volume = {113}, number = {11}, pages = {1587-1600}, pmid = {32918643}, issn = {1572-9699}, support = {BT/PR6119/GBD/27/370/2012//Department of Biotechnology, Ministry of Science and Technology (IN)/ ; }, mesh = {Animals ; Biofilms/*growth & development ; Caenorhabditis elegans/genetics/*microbiology ; Cronobacter sakazakii/*growth & development/*pathogenicity ; Lactobacillus/*physiology ; Longevity/genetics ; *Probiotics ; }, abstract = {The study reports protective role of potential probiotic cultures against infection by biofilm forming Cronobacter sakazakii in Caenorhabditis elegans model system. Among the fifteen indigenous potential probiotics, the cell free supernatant of Lactobacillus gastricus BTM7 possessed highest antimicrobial action and biofilm inhibition against C. sakazakii. The competitive exclusion assays revealed that preconditioning with probiotics resulted in increased mean life span of the nematode to 12-13 days as compared to 5-6 days when the pathogen was administered alone. Enhanced expression of the marker genes (pmk-1, daf-16 and skn-1) was observed during the administration of probiotic cultures. The highest expression of pmk-1 (2.5 folds) was observed with administration of L. gastricus BTM7. The principal component analysis on selected variables revealed that L. gastricus BTM7 has the potential to limit the infection of C. sakazakii in C. elegans and enhance the expression of key genes involved in extending life span of the worm.}, } @article {pmid32918326, year = {2021}, author = {Kurakado, S and Miyashita, T and Chiba, R and Sato, C and Matsumoto, Y and Sugita, T}, title = {Role of arthroconidia in biofilm formation by Trichosporon asahii.}, journal = {Mycoses}, volume = {64}, number = {1}, pages = {42-47}, doi = {10.1111/myc.13181}, pmid = {32918326}, issn = {1439-0507}, support = {JP20fk0108135h0201//Japan Agency for Medical Research and Development/ ; JP20K16000//Japan Society for the Promotion of Science/ ; }, mesh = {Basidiomycota/*physiology ; Biofilms/*growth & development ; Cell Adhesion ; Culture Media/chemistry ; Hydrophobic and Hydrophilic Interactions ; Hyphae ; Nitrogen ; Polystyrenes ; Spores, Fungal/*physiology ; Trichosporonosis/microbiology ; }, abstract = {BACKGROUND: Trichosporon asahii is the major causative agent of disseminated and deep-seated trichosporonosis. It is capable of forming biofilms on surfaces, leading to medical device-related infection.Trichosporon asahii may be present as yeast form, hyphae and/or arthroconidia; however, the relationship between its biofilm-forming ability and its morphological transition is unclear.

OBJECTIVES: We investigated whether the T. asahii morphological transition contributes to its biofilm formation. We also determined the conditions required to induce each of the morphologies.

METHODS: Three high- and three low-biofilm-producing strains (HBS and LBS, respectively) were selected using a biofilm formation assay, and the cell surface hydrophobicity of these six strains was measured. For each strain, the morphology was observed and the number of each morphological form (yeast form, hypha and arthroconidium) was counted to calculate the ratio. Finally, the ability of cells each morphological type to adhere to the polystyrene substrate was evaluated.

RESULTS: The HBS exhibited abundant arthroconidia and hyphae; in contrast, the LBS produced mainly hyphae with few or no arthroconidia. The production of hyphae was increased by nitrogen-containing medium, and the production of arthroconidia was increased by nitrogen-deficient medium. Cells incubated under nitrogen-deficient conditions showed higher adherence to a polystyrene surface than those incubated in the presence of nitrogen.

CONCLUSION: Arthroconidia of T. asahii play a key role in biofilm formation by promoting cellular adhesion.}, } @article {pmid32918121, year = {2021}, author = {de Sousa, ET and Lima-Holanda, AT and Sales, LS and Nobre-Dos-Santos, M}, title = {Combined effect of starch and sucrose on carbonic anhydrase VI activity in saliva and biofilm of children with early childhood caries. Exposure to starch and sucrose alters carbonic anhydrase VI activity in saliva and biofilm.}, journal = {Clinical oral investigations}, volume = {25}, number = {5}, pages = {2555-2568}, pmid = {32918121}, issn = {1436-3771}, support = {2017/17630-8//FAPESP/ ; }, mesh = {Biofilms ; Carbonic Anhydrases ; Child ; Child, Preschool ; *Dental Caries ; Dental Caries Susceptibility ; Humans ; Hydrogen-Ion Concentration ; *Saliva ; Starch ; Sucrose/pharmacology ; }, abstract = {OBJECTIVES: This study aimed to investigate whether combined exposure to starch and sucrose modifies the activity of carbonic anhydrase VI (CA VI) in saliva (Study 1) and biofilm (Study 2) of children with early childhood caries (ECC).

MATERIAL AND METHODS: For Study 1 and Study 2, respectively, 54 and 46 preschoolers aged 4 to 5 were allocated into two groups: caries-free (CF) and with ECC. Children were exposed to rinses with sucrose, starch, and sucrose plus starch solutions. CA VI activity, pH, and buffering capacity (BC) were evaluated in saliva and biofilm.

RESULTS: In Study 1, a significant reduction in saliva pH was observed after sucrose and sucrose plus starch rinses. CA VI activity was influenced by ECC independently of the type of carbohydrate to which children were exposed. CA VI activity was higher in children with ECC; however, after rinses, CA VI activity was reduced. In Study 2, biofilm pH and BC were reduced after rinses with sucrose and sucrose plus starch. CA VI activity was significantly high before rinse in ECC group when compared with CF group; however, no difference was observed between groups after rinses.

CONCLUSIONS: In saliva, exposure to starch and sucrose (isolated or combined) induced a reduction in CA VI activity in children with ECC. In biofilm, the combination of starch and sucrose did not modify CA VI activity in ECC children.

CLINICAL RELEVANCE: The responsivity of the CA VI reflects directly in important parameters related to the pH maintenance on the oral cavity.}, } @article {pmid32918096, year = {2021}, author = {Keleş, A and Keskin, C and Kalkan, M and Yakupoğulları, Y and Gül, M and Aydemir, H and Şahin, F}, title = {Visualization and characterization of Enterococcus faecalis biofilm structure in bovine dentin using 2D and 3D microscopic techniques.}, journal = {Archives of microbiology}, volume = {203}, number = {1}, pages = {269-277}, pmid = {32918096}, issn = {1432-072X}, support = {114S511//Türkiye Bilimsel ve Teknolojik Araştirma Kurumu (TR)/ ; }, mesh = {Animals ; *Biofilms ; Cattle ; Dentin/*microbiology ; Enterococcus faecalis/*physiology/*ultrastructure ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; X-Ray Microtomography ; }, abstract = {Bacterial biofilms are related to various dental and periodontal infectious diseases, and the characterization of this biological structure with micro-computed tomography (micro-CT) may offer valuable information for clinical and research applications. In this study, we aimed to develop a model to visualize three-dimensionally the biofilm structure on dentin using micro-CT. Dentin blocks were prepared and incubated in tryptic soy broth with Enterococcus faecalis (ATCC 29212). The control group did not receive any staining procedure, while groups 1 and 2 were stained with 100% and 50% barium sulfate, respectively. Transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) were used to detect biofilm formation, barium sulfate penetration, and microbial cell density in the biofilm. Micro-computed tomography (micro-CT) (SkyScan 1172, Bruker Co., Belgium) was used to visualize biofilm formation on the dentin blocks. Biofilm thicknesses were measured from 10 different locations on the specimen surfaces, using CTAn v.1.14.4 software. Obtained data were statistically analyzed using Kruskal-Wallis and Dunn's tests. TEM photomicrographs showed that barium sulfate could penetrate the biofilm structure. CLSM analysis showed that viable and total cell densities were similar between the control and barium sulfate-treated groups (P > 0.05), indicating barium sulfate had no significant influence on cell density. In barium sulfate-treated blocks, biofilm could be discriminated from the dentin, and its thickness could be measured with micro-CT. This study showed that bacterial biofilm on dentin could be characterized by micro-CT after barium sulfate staining without causing any significant side effect on viable and total cell densities.}, } @article {pmid32917757, year = {2020}, author = {Kim, S and Li, XH and Hwang, HJ and Lee, JH}, title = {Thermoregulation of Pseudomonas aeruginosa Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {22}, pages = {}, pmid = {32917757}, issn = {1098-5336}, mesh = {Biofilms/*growth & development ; *Body Temperature Regulation ; Cyclic GMP/analogs & derivatives/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Pseudomonas aeruginosa/*physiology ; }, abstract = {We investigated the effect of temperature on the biofilm formation of Pseudomonas aeruginosa and revealed that the biofilm formation increased rapidly at temperatures lower than 25°C. P. aeruginosa formed the most robust biofilm of a conspicuous mushroom-like structure at 20°C. However, when the temperature increased to 25°C, the biofilm formation rapidly decreased. Above 25°C, as the temperature rose, the biofilm formation increased again little by little despite its less-structured form, indicating that 25°C is the low point of biofilm formation. The intracellular 3',5'-cyclic diguanylate (c-di-GMP) levels also decreased rapidly as the temperature rose from 20 to 25°C. The expression levels of pelA, algD, and pslA encoding Pel, alginate, and Psl, respectively, were also dramatically affected by temperature, with pelA being regulated in a pattern similar to that of the intracellular c-di-GMP levels, and the pattern seen for algD regulation was the most similar to the actual biofilm formation pattern. Total exopolysaccharide production was thermoregulated and followed the regulation pattern of c-di-GMP. Interestingly, the thermoregulation patterns in biofilm formation were different depending on the strain of P. aeruginosa Unlike PAO1, another strain, PA14, showed a gradual decrease in biofilm formation and c-di-GMP in the range of 20 to 37°C, and P. aeruginosa clinical isolates also showed slightly different patterns in biofilm formation in conjunction with temperature change, suggesting that different strains may sense different temperature ranges for biofilm formation. However, it is obvious that P. aeruginosa forms more biofilms at lower temperatures and that temperature is an important factor in determining the biofilm formation.IMPORTANCE Biofilm formation is an important protection mechanism used by most microorganisms and provides cells with many advantages, like high infectivity, antibiotic resistance, and strong survivability. Since most persistent bacterial infections are believed to be associated with biofilms, biofilm control is an important issue in medicine, environmental engineering, and industry. Biofilm formation is influenced by various environmental factors. Temperature is the most direct environmental cue encountered by microorganisms. Here, we investigated the effect of temperature on the biofilm formation of P. aeruginosa, a notorious pathogen, and found that temperature is an important factor determining the amount and structure of biofilms. Low temperatures greatly increase biofilm formation and give biofilms a highly conspicuous structure. Although thermoregulation of biofilm formation is mainly mediated by c-di-GMP, some c-di-GMP-independent regulations were also observed. This study shows how biofilms are formed at various temperatures and provides new insights to control biofilms using temperature.}, } @article {pmid32917750, year = {2020}, author = {Rizzi, A and Leroux, J and Charron-Lamoureux, V and Roy, S and Beauregard, PB and Bellenger, JP}, title = {Bacillus subtilis Modulates Its Usage of Biofilm-Bound Iron in Response to Environmental Iron Availability.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {22}, pages = {}, pmid = {32917750}, issn = {1098-5336}, mesh = {Bacillus subtilis/growth & development/*physiology ; *Biofilms ; Biological Transport ; Iron/*metabolism ; }, abstract = {Iron (Fe) is one of the most important micronutrients for most life forms on earth. While abundant in soil, Fe bioavailability in oxic soil is very low. Under environmental conditions, bacteria need to acquire sufficient Fe to sustain growth while limiting the energy cost of siderophore synthesis. Biofilm formation might mitigate this Fe stress, since it was shown to accumulate Fe in certain Gram-negative bacteria and that this Fe could be mobilized for uptake. However, it is still unclear if, and to what extent, the amount of Fe accumulated in the biofilm can sustain growth and if the mobilization of this local Fe pool is modulated by the availability of environmental Fe (i.e., Fe outside the biofilm matrix). Here, we use a nondomesticated strain of the ubiquitous biofilm-forming soil bacterium Bacillus subtilis and stable Fe isotopes to precisely evaluate the origin of Fe during growth in the presence of tannic acid and hydroxides, used as proxies for different environmental conditions. We report that this B. subtilis strain can accumulate a large quantity of Fe in the biofilm, largely exceeding Fe associated with cells. We also report that only a fraction of biofilm-bound Fe is available for uptake in the absence of other sources of Fe in the vicinity of the biofilm. We observed that the availability of environmental Fe modulates the usage of this pool of biofilm-bound Fe. Finally, our data suggest that consumption of biofilm-bound Fe relates to the efficacy of B. subtilis to transport Fe from the environment to the biofilm, possibly through siderophores.IMPORTANCE Recent pieces of evidence suggest that Fe bound to the biofilm could assume at least two important functions, a local source of Fe for uptake and a support to extracellular metabolism, such as extracellular electron transfer. Our results show that B. subtilis can use biofilm-bound Fe for uptake only if it does not compromise Fe homeostasis of the biofilm, i.e., maintains a minimum Fe concentration in the biofilm for extracellular purposes. We propose a theoretical framework based on our results and recent literature to explain how B. subtilis manages biofilm-bound Fe and Fe uptake in response to environmental Fe availability. These results provide important insights into the management of biofilm-bound and environmental Fe by B. subtilis in response to Fe stress.}, } @article {pmid32917370, year = {2020}, author = {Kim, HW and Lee, NY and Park, SM and Rhee, MS}, title = {A fast and effective alternative to a high-ethanol disinfectant: Low concentrations of fermented ethanol, caprylic acid, and citric acid synergistically eradicate biofilm-embedded methicillin-resistant Staphylococcus aureus.}, journal = {International journal of hygiene and environmental health}, volume = {229}, number = {}, pages = {113586}, doi = {10.1016/j.ijheh.2020.113586}, pmid = {32917370}, issn = {1618-131X}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Caprylates/*pharmacology ; Citric Acid/*pharmacology ; Decontamination/methods ; Disinfectants/*pharmacology ; Ethanol/*pharmacology ; Fermentation ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Silicones ; }, abstract = {BACKGROUND: There is a growing need to develop a powerful bactericidal method with low ethanol concentrations due to the frequent ineffectiveness of traditional antibiotics against biofilms and the side effect of a high ethanol concentration.

OBJECTIVES: This study aims to develop a novel synergistic technique replacing a high-ethanol disinfectant.

METHODS: Low concentrations of fermented ethanol (FE, 10-20%) with naturally derived antimicrobials, citric acid (CTA, 0.5-1.0%) and caprylic acid (CAP, 0.05-0.15%), were examined against a methicillin-resistant S. aureus (MRSA) biofilm formed on silicone coupons (catheter materials).

RESULTS: CTA and CAP were identified as effective antimicrobials that exhibited a synergistic interaction with FE. Complete eradication of MRSA biofilms (>7 log reduction) was obtained within 5 min after treatment with 20% FE plus 1.0% CTA and 0.15% CAP at both 22 and 37 °C, while individual treatments with each material showed negligible bactericidal effects (<1 log reduction except 0.15% CAP treatment at 37 °C). No bacteria were recovered from the surface after the combined treatment (five enrichment tests). The developed compounds were able to disinfect surfaces with more than 5 log-reduction within only 1 min at 22 °C. Confocal microscopy images showed that the combination of all three materials resulted in remarkable membrane damage and cell detachment from the silicone surface.

DISCUSSON: Application of FE plus CTA and CAP, therefore, can be a valuable decontamination technique for medical devices or can work as a surface disinfectant, reducing the concerns regarding undesirable high ethanol concentrations in disinfectants.}, } @article {pmid32916616, year = {2020}, author = {Svendsen, SB and El-Taliawy, H and Carvalho, PN and Bester, K}, title = {Concentration dependent degradation of pharmaceuticals in WWTP effluent by biofilm reactors.}, journal = {Water research}, volume = {186}, number = {}, pages = {116389}, doi = {10.1016/j.watres.2020.116389}, pmid = {32916616}, issn = {1879-2448}, mesh = {Attention ; Biofilms ; Bioreactors ; *Pharmaceutical Preparations ; Waste Disposal, Fluid ; Wastewater ; *Water Pollutants, Chemical/analysis ; }, abstract = {Conventional wastewater treatment lacks the ability to remove many pharmaceuticals. This is leading to emissions to the natural aquatic environment, where these compounds pose a risk to the aquatic organisms. An advanced wastewater treatment technique that has shown promising results is Moving Bed Biofilm Reactors (MBBR). Initial degradation velocity and degradation rate constants of the pharmaceuticals are important parameters for designing an optimal MBBR system; however, the degradation efficiency varies across studies and one of the most plausible causes might be initial concentration. Thus, to verify the effect of initial concentration, the degradation of a mixture of 18 pharmaceuticals at different initial concentrations was studied. For this study MBBR's with very low BOD loading were used as they were conditioned with effluent water. The experiment was set up as a MBBR batch incubation, using effluent wastewater as medium, spiked with the 18 pharmaceuticals in seven different concentration levels (approximately 0-300 µg L[-1]). The degradation of 14 out of 18 pharmaceuticals was concentration-dependent. The initial degradation velocity of the pharmaceuticals was either proportional to the initial concentration or was following a typical Michaelis-Menten kinetic. The degradation velocity of one compound, i.e., sulfamethizole might have been inhibited at high concentrations. The degradation rate constants from single first-order fittings (KSFO) for some compounds deviated from the expected behavior at low concentrations (below 10 µg L[-1]). This is suggested to be caused by simplicity of the Michaelis-Menten model, not taking possible occurrence of co-metabolism and mass-transfer limitations into account at low concentrations. This study underlines the fact that K values cannot be interpreted without paying attention to the tested concentration level. Furthermore, it shows that the used MBBRs was able to handle high concentrations of pharmaceuticals, and that the most efficient removal occurs at concentrations above 100 µg L[-1].}, } @article {pmid32916327, year = {2020}, author = {Banerjee, S and Ghosh, D and Vishakha, K and Das, S and Mondal, S and Ganguli, A}, title = {Photodynamic antimicrobial chemotherapy (PACT) using riboflavin inhibits the mono and dual species biofilm produced by antibiotic resistant Staphylococcus aureus and Escherichia coli.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {32}, number = {}, pages = {102002}, doi = {10.1016/j.pdpdt.2020.102002}, pmid = {32916327}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Biofilms ; Escherichia coli ; Extracellular Polymeric Substance Matrix ; *Methicillin-Resistant Staphylococcus aureus ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Riboflavin/pharmacology ; Staphylococcus aureus ; }, abstract = {PURPOSE: Multispecies biofilms play a significant role in persistent infections. Furthermore, by interspecies transfer of antibiotic resistance genes, multispecies biofilms spread antibiotic resistance. The purpose of this study was to investigate the effect of Photodynamic Antimicrobial Chemotherapy (PACT) using riboflavin on mono and multi species biofilms.

METHODS: For this we used two clinically relevant opportunistic pathogens species E. coli and S. aureus as mono-species and multispecies biofilms. We did broth dilution assay for antibacterial, crystal violet assay for biofilms and fluorometric study for reactive oxygen species (ROS) and extracellular polymeric substance (EPS) production by phenol-HCl method.

RESULTS: Antibacterial study revealed that photo-illuminated riboflavin shows bactericidal effect against each bacteria and their mix culture. E. coli was found to be little more resistant than S. aureus. Crystal violet assay revealed photo-illuminated riboflavin shows anti-biofilms activity against both mono and mix species biofilms. But mix species biofilms were more resistant to PACT than mono species biofilms. Further study revealed this may be due to the interaction between different EPS production, hence in mix species biofilms EPS production is less affected after PACT than mono species biofilms. We found photo-illuminated riboflavin increased the intracellular ROS production.

CONCLUSION: Photo-illuminated riboflavin shows bactericidal and anti-biofilms effect against each bacteria and their mix culture. Photo-illuminated increased intracellular ROS production, which may induce the oxidative stress and destroy the respiratory system of bacteria.}, } @article {pmid32916198, year = {2020}, author = {Baidamshina, DR and Koroleva, VA and Trizna, EY and Pankova, SM and Agafonova, MN and Chirkova, MN and Vasileva, OS and Akhmetov, N and Shubina, VV and Porfiryev, AG and Semenova, EV and Sachenkov, OA and Bogachev, MI and Artyukhov, VG and Baltina, TV and Holyavka, MG and Kayumov, AR}, title = {Anti-biofilm and wound-healing activity of chitosan-immobilized Ficin.}, journal = {International journal of biological macromolecules}, volume = {164}, number = {}, pages = {4205-4217}, doi = {10.1016/j.ijbiomac.2020.09.030}, pmid = {32916198}, issn = {1879-0003}, mesh = {Biofilms/*drug effects ; Chitosan/*chemistry ; Drug Carriers/chemistry ; *Enzymes, Immobilized ; Ficain/*chemistry/*pharmacology ; Hydrogen-Ion Concentration ; Kinetics ; Microbial Sensitivity Tests ; Proteolysis ; Solubility ; Staphylococcus aureus/drug effects ; Wound Healing/*drug effects ; }, abstract = {Biofouling is among the key factors slowing down healing of acute and chronic wounds. Here we report both anti-biofilm and wound-healing properties of the chitosan-immobilized Ficin. The proposed chitosan-adsorption approach allowed preserving ~90% of the initial total activity of the enzyme (when using azocasein as a substrate) with stabilization factor of 4.9, and ~70% of its specific enzymatic activity. In vitro, the chitosan-immobilized Ficin degraded staphylococcal biofilms, this way increasing the efficacy of antimicrobials against biofilm-embedded bacteria. In vivo, in the presence of Ficin (either soluble or immobilized), the S.aureus-infected skin wound areas in rats reduced twofold after 4 instead of 6 days treatment. Moreover, topical application of the immobilized enzyme resulted in a 3-log reduction of S. aureus cell count on the wound surfaces in 6 days, compared to more than 10 days required to achieve the same effect in control. Additional advantages include smoother reepithelisation, and new tissue formation exhibiting collagen structure characteristics closely reminiscent of those observed in the native tissue. Taken together, our data suggest that both soluble and immobilized Ficin appear beneficial for the treatment of biofilm-associated infections, as well as speeding up wound healing and microbial decontamination.}, } @article {pmid32913155, year = {2020}, author = {Suer, K and Ozkan, L and Guvenir, M}, title = {Antimicrobial effects of sodium hypochlorite and Er,Cr:YSGG laser against Enterococcus faecalis biofilm.}, journal = {Nigerian journal of clinical practice}, volume = {23}, number = {9}, pages = {1188-1193}, doi = {10.4103/njcp.njcp_632_18}, pmid = {32913155}, issn = {1119-3077}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Chromium ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*drug effects ; Erbium ; Gallium ; Humans ; Lasers, Solid-State/*therapeutic use ; Root Canal Irrigants/*pharmacology ; Root Canal Preparation ; Root Canal Therapy/methods ; Scandium ; Sodium Hypochlorite/*pharmacology ; Yttrium ; }, abstract = {AIMS: The aim of this study was to investigate the antimicrobial effect of Erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser with and without NaOCl solution. A total of 81 extracted human mandibular premolar teeth were used.

MATERIALS AND METHODS: After root canal preparation and sterilization, the samples were inoculated with E. faecalis for 24 hours. The specimens were divided into 4 experimental groups. Group 1 (n = 25) was irradiated with 2 W laser, group 2 (n = 25) was irradiated with 0.75 W laser in combination with 2.5% NaOCl, group 3 (n = 25) was irrigated with 5% NaOCl and group 4 (n = 6) was not treated. Statistical analysis was performed by using Wilcoxon Signed Ranks, Mann-Whitney U and Kruskal-Wallis H tests.

RESULTS: The combination of 0.75 W laser with 2.5% NaOCl regime was found to be just as effective at inhibiting the growth of E. faecalis and sterilization of all root canals as 5% NaOCl irrigation (P > 0.001). The 2 W laser had significant bactericidal effect in infected root canals however it did not eradicate all bacteria. The SEM observations were in accordance with the microbiologic findings.

CONCLUSIONS: Within the limitations of this laboratory study, NaOCl irrigation improved the antimicrobial effect of Er,Cr:YSGG laser irradiation. When the toxic effects of high percentage of NaOCl was considered, the combination of low-powered laser and low concentration of NaOCl can be used as an effective disinfection method in root canal treatment.}, } @article {pmid32911269, year = {2020}, author = {Pérez, J and Laureni, M and van Loosdrecht, MCM and Persson, F and Gustavsson, DJI}, title = {The role of the external mass transfer resistance in nitrite oxidizing bacteria repression in biofilm-based partial nitritation/anammox reactors.}, journal = {Water research}, volume = {186}, number = {}, pages = {116348}, doi = {10.1016/j.watres.2020.116348}, pmid = {32911269}, issn = {1879-2448}, mesh = {*Ammonium Compounds ; Bacteria/genetics ; Biofilms ; Bioreactors ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; Sewage ; }, abstract = {A model-based study was developed to analyse the behaviour of Moving Bed Biofilm Reactor (MBBR) and Integrated Fixed-Film Activated Sludge (IFAS) reactor configurations for the removal of nitrogen in the main water line of municipal wastewater treatment plants via partial nitritation/anammox (PN/AMX). The basic principles and underlying mechanisms linking operating conditions to process performance were investigated, with particular focus on nitrite oxidizing bacteria (NOB) repression and resulting volumetric conversion rates. The external mass transfer resistance is a major factor differentiating granular sludge PN/AMX processes from MBBR or IFAS systems. The external mass transfer resistance was found to promote the metabolic coupling between anammox (AMX) and ammonia oxidizing bacteria (AOB), crucial for NOB repression in the biofilm. Operation at low bulk DO prevents NOB proliferation in the flocs of IFAS systems as AMX activity limits nitrite availability (the so-called AMX nitrite sink). Importantly, the effectiveness of the AMX nitrite sink strongly depends on the AMX sensitivity to oxygen. Also, over a broad range of operational conditions, the seeding of AOB from the biofilm played a crucial role in maintaining their activity in the flocs. From a practical perspective, while low DO promotes NOB repression, lower nitrogen loads have to be applied to maintain the same effluent quality. Thus, a trade-off between NOB repression and volumetric conversion capacity needs to be defined. To this end, IFAS allow for higher volumetric rates, but the window of operating conditions with effective NOB repression is smaller than that for MBBR. Ultimately, this study identified the principles controlling NOB in MBBR and IFAS systems and the key differences with granular reactors, allowing for the interpretation of (seemingly contradictory) published experimental results.}, } @article {pmid32911240, year = {2020}, author = {Habashi, N and Marom, T and Steinberg, D and Zacks, B and Tamir, SO}, title = {Biofilm distribution on tympanostomy tubes: An ex vivo descriptive study.}, journal = {International journal of pediatric otorhinolaryngology}, volume = {138}, number = {}, pages = {110350}, doi = {10.1016/j.ijporl.2020.110350}, pmid = {32911240}, issn = {1872-8464}, mesh = {Bacteria ; *Biofilms ; Child, Preschool ; Humans ; Male ; Middle Ear Ventilation/*adverse effects/*instrumentation ; Otitis Media with Effusion/*surgery ; Postoperative Complications/*microbiology ; Prostheses and Implants/*microbiology ; }, abstract = {BACKGROUND: Tympanostomy tube (TT) insertion is a common procedure in children with otitis media with effusion. Post-TT otorrhea (PTTO) is a frequent post-operative complication. Biofilms are involved in chronic PTTO cases.

OBJECTIVE: To describe and qualitatively analyze the geometry and sites prone to biofilms on removed TTs, relatively to their position in the ear, past medical/surgical history and PTTO presence.

METHODS: Biofilms presence and topographic distribution on TTs were ex vivo evaluated by using scanning electron microscope, confocal microscope and stereo-microscope.

RESULTS: Forty-eight TTs from 30 children were analyzed. Indications for removal were: 71% due to retained TTs (average time from insertion: 24.4 ± 15.1 months), 23% due to chronic PTTO, and 6% due to TT obstruction/dysfunction. Different types of bacterial biofilms were detected on all TTs, regardless the time from their insertion nor their types. Biofilms were observed more on the perpendicular junction and on the internal lumen, and more biofilm colonies were detected on the medial part, facing the middle ear mucosa. TTs removed from children with PTTO exhibited more biofilm colonies when compared to their peers. Of the 16 children who underwent adenoidectomy concomitantly with TT insertion, 10 (62%) children were sent for TT removal due to retained TTs, and 6 (38%) children due to chronic PTTO (p = 0.03).

CONCLUSION: Descriptive analysis of biofilm topographic distribution demonstrated adhesions on specific TT areas: perpendicular junctions and the internal lumen. Such "prone zones" may be the future target areas for changes in TT geometry or can be specifically coated with anti-biofilm materials.}, } @article {pmid32911175, year = {2021}, author = {Wang, B and Lu, L and Zhang, Y and Fang, K and An, D and Li, H}, title = {Removal of bisphenol A by waste zero-valent iron regulating microbial community in sequencing batch biofilm reactor.}, journal = {The Science of the total environment}, volume = {753}, number = {}, pages = {142073}, doi = {10.1016/j.scitotenv.2020.142073}, pmid = {32911175}, issn = {1879-1026}, mesh = {Benzhydryl Compounds ; Biofilms ; Bioreactors ; Iron ; *Microbiota ; Phenols ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {The removal of bisphenol A (BPA) by waste zero-valent iron (ZVI) regulating microbial community in sequencing batch biofilm reactor (SBBR) was investigated. Compared with SBBR-BPA, the acclimation time of microorganisms in the presence of waste ZVI and BPA (SBBR-ZVI+BPA) decreased from 56 d to 49 d. During stable operation period, BPA was removed completely at 150th min and 100th min in the SBBR-BPA and SBBR-ZVI+BPA, respectively. The optimal initial pH and BPA concentration in the SBBRs were respectively 8.0 and 10 mg/L. The composition and content analysis of extracellular polymeric substances (EPS) using fluorescence spectrometer showed that the yield of EPS was enhanced by the addition of ZVI. The analysis of microbial community structure in the SBBRs using Illumina Miseq sequencing method indicated that the indexes of ACE, Chao1 and Shannon were higher and Simpson index was lower in the SBBR-ZVI+BPA. Moreover, the abundance of BPA biodegradation strains was increased in the presence of ZVI. This study provided a promising method with low cost of effectively removing BPA from wastewater.}, } @article {pmid32910518, year = {2020}, author = {Lee, CH and Chen, YC and Chen, IL and Chen, FJ and Chien, CC}, title = {Impact of biofilm production by Candida species and antifungal therapy on mortality of patients with candidemia.}, journal = {Mycoses}, volume = {63}, number = {12}, pages = {1382-1391}, doi = {10.1111/myc.13179}, pmid = {32910518}, issn = {1439-0507}, support = {CMRPG 8H0491//Chang Gung Memorial Hospital, Taiwan/ ; }, mesh = {Adult ; Aged ; Aged, 80 and over ; Biofilms/drug effects/*growth & development ; Candida/*drug effects/pathogenicity/physiology ; Candidemia/*drug therapy/*mortality ; Caspofungin/therapeutic use ; Echinocandins/therapeutic use ; Female ; Fluconazole/therapeutic use ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Multivariate Analysis ; Taiwan ; Tertiary Care Centers ; }, abstract = {BACKGROUND AND OBJECTIVES: Few studies have investigated the clinical outcomes of patients with candidemia caused by Candida species with different levels of biofilm formation. We aimed to investigate the impact of antifungal therapy on the outcome of candidemia caused by Candida species that were categorised as low biofilm formers (LBFs), moderate biofilm formers (MBFs), and high biofilm formers (HBFs).

METHODS: Adults with candidemia caused by LBF and HBF/MBF Candida species that were susceptible to fluconazole and caspofungin were included to investigate the impact of treatment with fluconazole vs an echinocandin on 30-day crude mortality.

RESULTS: In total, 215 patients with candidemia received fluconazole and 116 patients received an echinocandin. In multivariate analysis, Pittsburgh bacteremia score ≥ 4 (adjusted odds ratio [AOR] =2.42; 95% confidence interval [CI], 1.32-4.41), malignancy (AOR = 3.45; 95% CI, 1.83-6.51), not removing the central venous catheter within 48 hours of a positive blood culture (AOR = 4.69; 95% CI, 2.61-8.45), and treatment with fluconazole for candidemia due to HBF/MBF Candida spp. (AOR = 2.23; 95% CI, 1.22-4.06) were independent factors associated with 30-day mortality. Of the 165 patients infected by HBF/MBF Candida isolates, those who received azole therapy had a significantly higher sepsis-related mortality rate than those who received echinocandin therapy (44.9% [49/109] vs 26.8% [15/56], P = .03).

CONCLUSIONS: There was a trend of an independent association between fluconazole treatment and poor outcomes in the patients infected by HBF/MBF Candida strains.}, } @article {pmid32910268, year = {2020}, author = {Forwood, DL and Bryce, EK and Caro, E and Holman, DB and Meale, SJ and Chaves, AV}, title = {Influence of probiotics on biofilm formation and diversity of bacteria colonising crop sorghum ensiled with unsalable vegetables.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {20}, pages = {8825-8836}, doi = {10.1007/s00253-020-10877-5}, pmid = {32910268}, issn = {1432-0614}, mesh = {Animals ; Bacteria/genetics ; Biofilms ; Digestion ; Fermentation ; *Probiotics ; RNA, Ribosomal, 16S/genetics/metabolism ; *Refuse Disposal ; Rumen/metabolism ; Silage ; *Sorghum ; Vegetables ; Zea mays ; }, abstract = {The objective of this study was to characterise in situ digestion kinetics and bacterial colonisation of crop sorghum ensiled with unsalable carrot or pumpkin at 0, 20 or 40% dry matter (DM). Silages with or without the application of a commercial probiotic were incubated in situ for 0, 3, 6, 9, 24 and 48 h. Calculation of in situ digestion kinetics was conducted for DM, organic matter and neutral detergent fibre (aNDF). The V4 region of the 16S rRNA gene was sequenced to determine the composition and diversity of bacteria colonising the silage. Organic matter and DM digestion kinetics indicated that greater vegetable inclusion increased (P < 0.05) the soluble fraction and effective degradability. Bacterial richness at 48 h incubation was greater (P = 0.02) in 20% carrot and 40% pumpkin treatments, compared with the control. An effect of level × probiotic was observed with increased Shannon diversity (P = 0.01) for 40% carrot and 20% pumpkin probiotic treatments, respectively. Primary colonising bacteria were members of the Prevotella genus, dominating after 3 and 6 h of incubation. The abundance of Prevotella increased by 4.1% at 3 h (P < 0.01) and by 4.7% at 9 h incubation with probiotics, compared with the control. Secondary biofilm colonisers included members of Treponema, Saccharofermentans, Fibrobacter, Ruminobacter and Anaerosporobacter genera, dominant from 9 h incubation onward. This study demonstrated that including unsalable vegetables at 20 or 40% DM increases the soluble fraction and effective degradability of sorghum silage during in situ digestion and increases diversity of bacteria colonising ensiled vegetables within the rumen. KEY POINTS: • Ensiling unsalable vegetables is a viable strategy to reduce food waste. • Ensiled vegetables increased in situ soluble fraction and effective degradability. • Bacterial richness at 48 h incubation improved with 20% carrot or 40% pumpkin. • Diversity of colonising rumen bacteria increased with carrot or pumpkin inclusion.}, } @article {pmid32910213, year = {2020}, author = {Baldiris-Avila, R and Montes-Robledo, A and Buelvas-Montes, Y}, title = {Phylogenetic Classification, Biofilm-Forming Capacity, Virulence Factors, and Antimicrobial Resistance in Uropathogenic Escherichia coli (UPEC).}, journal = {Current microbiology}, volume = {77}, number = {11}, pages = {3361-3370}, pmid = {32910213}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Colombia ; Drug Resistance, Bacterial ; *Escherichia coli Infections/drug therapy ; Humans ; Phylogeny ; *Urinary Tract Infections ; *Uropathogenic Escherichia coli/genetics ; Virulence Factors/genetics ; }, abstract = {Uropathogenic Escherichia coli (UPEC) is the main cause of urinary tract infections; in recent years, its importance as a pathogen has increased due to the emergence of hypervirulent and multiresistant strains. In this study, 190 urinary isolates of E. coli were assigned into the seven phylogenetic groups A (11.1%), B1 (4.7%), B2 (46.8%), C (5.8%) D (25.3%) F (2.6%), and Clade I (2.1%), and various virulence genes were examined with polymerase chain reaction methods. All isolates had at least one virulence factor of the 9 analyzed fyuA (81.1%), fimH (96.8%), iutA (74.7%), ompT (66.8%), kpsMTII (66.8%), traT (58.9%), PAI (43.6%), PapAH (26.3%), and usp (3.2%). The results showed a direct relationship between the virulence factors and phylogenetic group A and B2. Further, virulence genetic profiles fimH, fyuA, ompT, traT, and kpsMTII correlated with the production of strong biofilm, multidrug resistance, and the production of moderate hemolysin. These results suggest that these strains may become reservoirs of genes that encode virulence factors, which could be transferred horizontally enhancing their genomic background and high possibility of acquiring new genetic information for possible dissemination. This study provides the first description of phylogroups in UPEC in the Colombian Caribbean and the association with virulence factor profile, antimicrobial susceptibility, and their possible role in the epidemiology in Colombia.}, } @article {pmid32908525, year = {2020}, author = {Socohou, A and Sina, H and Degbey, C and Nanoukon, C and Chabi-Sika, K and Ahouandjinou, H and Lehmane, H and Baba-Moussa, F and Baba-Moussa, L}, title = {Antibiotics Resistance and Biofilm Formation Capacity of Staphylococcus spp. Strains Isolated from Surfaces and Medicotechnical Materials.}, journal = {International journal of microbiology}, volume = {2020}, number = {}, pages = {6512106}, pmid = {32908525}, issn = {1687-918X}, abstract = {Staphylococcus spp. is most often implicated in nosocomial infections. The objective of this study is to evaluate the susceptibility to antibiotics and the biofilm formation capacity of staphylococci species isolated from surfaces and medicotechnical materials at the university hospital center of Abomey-Calavi/Sô-Ava in Benin. Samples were collected according to ISO/DIS14698-1 standard from the surfaces and medicotechnical materials by the dry swab method. The isolation of Staphylococcus strains was performed on Chapman agar, and their identification was performed using microscopic and biochemical methods. The susceptibility of Staphylococcus isolates to antibiotics was evaluated by the disc diffusion method according to EUCAST and CLSI recommendations. The biofilm formation was qualitatively assessed using microplates. Of the 128 surfaces and medicotechnical material samples analyzed, 77% were contaminated with Staphylococcus spp. Thirteen species of Staphylococcus were isolated in different proportions but the pediatric department was the most contaminated (33%) by S. aureus. Resistance to antibiotics considerably varies according to the species of Staphylococcus. However, antibiotics such as chloramphenicol and vancomycin are the most effective on S. aureus, whereas coagulase-negative staphylococci developed less resistance to gentamycin and ciprofloxacin. The biofilm test reveals that 37% of our isolated strains were biofilm formers. Although regular monitoring of hospital hygiene is crucial, the optimal use of antibiotics is a cornerstone of reducing antimicrobial resistance.}, } @article {pmid32908520, year = {2020}, author = {Abebe, GM}, title = {The Role of Bacterial Biofilm in Antibiotic Resistance and Food Contamination.}, journal = {International journal of microbiology}, volume = {2020}, number = {}, pages = {1705814}, pmid = {32908520}, issn = {1687-918X}, abstract = {Biofilm is a microbial association or community attached to different biotic or abiotic surfaces or environments. These surface-attached microbial communities can be found in food, medical, industrial, and natural environments. Biofilm is a critical problem in the medical sector since it is formed on medical implants within human tissue and involved in a multitude of serious chronic infections. Food and food processing surface become an ideal environment for biofilm formation where there are sufficient nutrients for microbial growth and attachment. Therefore, biofilm formation on these surfaces, especially on food processing surface becomes a challenge in food safety and human health. Microorganisms within a biofilm are encased within a matrix of extracellular polymeric substances that can act as a barrier and recalcitrant for different hostile conditions such as sanitizers, antibiotics, and other hygienic conditions. Generally, they persist and exist in food processing environments where they become a source of cross-contamination and foodborne diseases. The other critical issue with biofilm formation is their antibiotic resistance which makes medication difficult, and they use different physical, physiological, and gene-related factors to develop their resistance mechanisms. In order to mitigate their production and develop controlling methods, it is better to understand growth requirements and mechanisms. Therefore, the aim of this review article is to provide an overview of the role of bacterial biofilms in antibiotic resistance and food contamination and emphasizes ways for controlling its production.}, } @article {pmid32908166, year = {2020}, author = {Trizna, EY and Yarullina, MN and Baidamshina, DR and Mironova, AV and Akhatova, FS and Rozhina, EV and Fakhrullin, RF and Khabibrakhmanova, AM and Kurbangalieva, AR and Bogachev, MI and Kayumov, AR}, title = {Bidirectional alterations in antibiotics susceptibility in Staphylococcus aureus-Pseudomonas aeruginosa dual-species biofilm.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {14849}, pmid = {32908166}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; Symbiosis/*drug effects ; }, abstract = {In mixed infections, the bacterial susceptibility differs significantly compared to monocultures of bacteria, and generally the concentrations of antibiotics required for the treatment increases drastically. For S. aureus and P. aeruginosa dual species biofilms, it has been numerously reported that P. aeruginosa decreases S. aureus susceptibility to a broad range of antibiotics, including beta-lactams, glycopeptides, aminoglycosides, macrolides, while sensitizes to quinolones via secretion of various metabolites. Here we show that S. aureus also modulates the susceptibility of P. aeruginosa to antibiotics in mixed cultures. Thus, S. aureus-P. aeruginosa consortium was characterized by tenfold increase in susceptibility to ciprofloxacin and aminoglycosides compared to monocultures. The same effect could be also achieved by the addition of cell-free culture of S. aureus to P. aeruginosa biofilm. Moreover, similar increase in antibiotics efficacy could be observed following addition of S. aureus suspension to the P. aeruginosa mature biofilm, compared to P. aeruginosa monoculture, and vice versa. These findings open promising perspectives to increase the antimicrobial treatment efficacy of the wounds infected with nosocomial pathogens by the transplantation of the skin residential microflora.}, } @article {pmid32908042, year = {2021}, author = {Mao, B and Xie, Y and Yang, H and Yu, C and Ma, P and You, Z and Tsauo, C and Chen, Y and Cheng, L and Han, Q}, title = {Casein phosphopeptide-amorphous calcium phosphate modified glass ionomer cement attenuates demineralization and modulates biofilm composition in dental caries.}, journal = {Dental materials journal}, volume = {40}, number = {1}, pages = {84-93}, doi = {10.4012/dmj.2019-325}, pmid = {32908042}, issn = {1881-1361}, mesh = {Biofilms ; Calcium Phosphates ; Cariostatic Agents ; Caseins/pharmacology ; *Dental Caries/drug therapy/prevention & control ; *Glass Ionomer Cements/pharmacology ; Humans ; Phosphopeptides ; Tooth Remineralization ; }, abstract = {The study investigated the effects of the modified conventional glass ionomer cement (GIC) incorporated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on biofilm composition of dental caries. Shear bond strength, durability tests, adhesive remnant index (ARI) and scanning electron microscope were used to measure the physical properties. Microhardness and ions release were determined to evaluate anti-demineralization effects; growth of the biofilm and its composition were assessed using MTT assay and Q-PCR assay. All experimental groups exhibited a significant stimulation of ions release, and reduced attenuation of microhardness. Nearly 39% reduction in the bacterial biofilm was observed with 5% CPP-ACP group. The regulation ability is mainly manifested in the inhibition of S. mutans and promotion of S. gordonii. The modified GICs by exhibiting anti-demineralization effects potentially lead to a reduction in the cariogenicity of plaque and can serve as a putative promising remineralization system with both enhanced antimicrobial and remineralization properties.}, } @article {pmid32906685, year = {2020}, author = {Racenis, K and Kroica, J and Rezevska, D and Avotins, L and Skuditis, E and Popova, A and Puide, I and Kuzema, V and Petersons, A}, title = {S. aureus Colonization, Biofilm Production, and Phage Susceptibility in Peritoneal Dialysis Patients.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32906685}, issn = {2079-6382}, abstract = {Peritonitis caused by Staphylococcusaureus is of major importance in peritoneal dialysis (PD) patients due to its great virulence profile and biofilm formation ability. Bacteriophages are a potential tool to treat peritonitis resulting from biofilm-associated infections. We screened S. aureus colonization in 71 PD patients from the nasal cavity, groin, and PD exit-site regions and analyzed clinical outcomes in these patients. We performed biofilm-formation testing of different strains and compared the isolates of one patient to detect phenotypic differences in S. aureus. Phage cocktails were used to detect S. aureus in vitro susceptibility. An adaptation procedure was performed in cases of bacterial resistance. Around 30% of PD patients (n = 21) were found to be S. aureus carriers; from these, a total of 34 S. aureus strains were isolated, of which 61.8% (n = 21) produced a strong biofilm. Phenotypic differences in strain biofilm production were detected in eight patients out of ten. All strains were sensitive to commonly used antibiotics. Broadly positive phage lytic activity (100%) was observed in six cocktails out of seven, and bacterial resistance towards phages was overcome using adaptation. Overall phages showed a promising in vitro effect in biofilm-forming S. aureus strains.}, } @article {pmid32905001, year = {2020}, author = {Montenegro, LAS and Silva E Farias, IP and de Araújo, EC and de Pontes, JC and Raymundo, ML and de Sousa, SA and Almeida, LFD and Cavalcanti, YW}, title = {Biochemical and microbiological analysis of the saliva of institutionalized elderly: With edentulism, use of dentures and presence of biofilm.}, journal = {Journal of clinical and experimental dentistry}, volume = {12}, number = {7}, pages = {e632-e637}, pmid = {32905001}, issn = {1989-5488}, abstract = {BACKGROUND: To analyze biochemical and microbiological parameters of the saliva of institutionalized elders and to investigate the relation of these parameters with edentulism, use of dentures and presence of biofilm.

MATERIAL AND METHODS: A cross-sectional study carried was out in seven long-term institutions. Samples (n=161) of unstimulated saliva were collected for analysis of salivary flow, quantification of total proteins and identification of microorganisms. Oral examination was carried out to verify the number of missing teeth, the use of dentures and the presence of visible biofilm on the surface of teeth and dentures. Associations were performed using chi-square or Fisher's exact test (α<0.05). Mann-Whitney Test was used to identify differences in the salivary flow and total proteins (α<0.05).

RESULTS: There was no association between the type of edentulism and use of dentures with biochemical and microbiological parameters of saliva (p>0.05). Associations were observed between the presence of dentures biofilm and the colonization of Streptococcus sp. (p=0.038) and Candida sp. (p=0.03).

CONCLUSIONS: The absence of teeth and use of dentures do not influence the amount of total proteins and the microorganisms count in saliva. Denture biofilms are associated with the presence of Streptococcus sp. and Candida sp. in saliva of institutionalized elders. Key words:Candida, long-stay institutions for elders, saliva, Streptococcus, Staphylococcus.}, } @article {pmid32903711, year = {2020}, author = {Kumari, P and Nath, Y and Murty, US and Ravichandiran, V and Mohan, U}, title = {Sortase A Mediated Bioconjugation of Common Epitopes Decreases Biofilm Formation in Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1702}, pmid = {32903711}, issn = {1664-302X}, abstract = {Staphylococcus aureus is one of the most notorious pathogens and is frequently associated with nosocomial infections imposing serious risk to immune-compromised patients. This is in part due to its ability to colonize at the surface of indwelling medical devices and biofilm formation. Combating the biofilm formation with antibiotics has its own challenges like higher values of minimum inhibitory concentrations. Here, we describe a new approach to target biofilm formation by Gram positive bacteria. Sortase A is a transpeptidase enzyme which is responsible for tagging of around ∼22 cell surface proteins onto the outer surface. These proteins play a major role in the bacterial virulence. Sortase A recognizes its substrate through LPXTG motif. Here, we use this approach to install the synthetic peptide substrates onS. aureus. Sortase A substrate mimic, 6His-LPETG peptide was synthesized using solid phase peptide chemistry. Incorporation of the peptide on the cell surface was measured using ELISA. Effect of peptide incubation on Staphylococcus aureus biofilm was also studied. 71.1% biofilm inhibition was observed with 100 μM peptide while on silicon coated rubber latex catheter, 45.82% inhibition was observed. The present work demonstrates the inability of surface modified S. aureus to establish biofilm formation thereby presenting a novel method for attenuating its virulence.}, } @article {pmid32903686, year = {2020}, author = {Di Lodovico, S and Menghini, L and Ferrante, C and Recchia, E and Castro-Amorim, J and Gameiro, P and Cellini, L and Bessa, LJ}, title = {Hop Extract: An Efficacious Antimicrobial and Anti-biofilm Agent Against Multidrug-Resistant Staphylococci Strains and Cutibacterium acnes.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1852}, pmid = {32903686}, issn = {1664-302X}, abstract = {Bacteria belonging to Staphylococcus genus, in particular methicillin-resistant Staphylococcus aureus and multidrug-resistant Staphylococcus epidermidis, together with Cutibacterium acnes are the main strains involved in skin disease. The increase in multidrug-resistant bacteria has revived attention on natural compounds as alternative agents for the treatment management. Among these, hop extract, a hydroalcoholic solution obtained from experimental crops of Humulus lupulus L. variety cascade (hop), displays diverse biological properties including an antimicrobial one. The aim of this study was to evaluate the antimicrobial activity and the capacity to inhibit the biofilm formation of a characterized hop extract against S. aureus and S. epidermidis multidrug-resistant strains and against a C. acnes strain. The hop extract was characterized by (i) phytochemical analysis through a reversed-phase high-performance liquid chromatography (HPLC)-fluorimetric method, (ii) biocompatibility test with Artemia salina L., (iii) cytotoxicity against two cell lines, (iv) docking analysis, and (v) antimicrobial and antibiofilm activities by detection of zones inhibition, minimal inhibitory concentrations (MICs), biomass quantification, and cell viability. The hop extract was biocompatible and non-cytotoxic at all tested concentrations. HPLC analysis revealed significant levels of gallic acid, resveratrol, and rutin. This last compound was the most representative displaying a high affinity against PBP2a and KAS III (Ki values in the submicromolar range). The characterized hop extract showed a good antimicrobial action with MICs ranging from 1 to 16 μg/mL and was able to inhibit the biofilm formation of all tested strains, except for two S. aureus strains. The biofilm formed in presence of the hop extract was significantly reduced in most cases, even when present at a concentration of 1/4 MIC. The live/dead images showed a remarkable inhibition in the biofilm formation by hop extract with a weak killing action. Overall, the tested hop extract is a good candidate to further explore for its use in the prevention of infection particularly, by multidrug-resistant Gram-positive pathogens.}, } @article {pmid32903626, year = {2020}, author = {Yu, H and Xiong, J and Qiu, J and He, X and Sheng, H and Dai, Q and Li, D and Xin, R and Jiang, L and Li, Q and Chen, Q and Peng, J and Wang, M and Rao, X and Zhang, K}, title = {Type III Secretion Protein, PcrV, Impairs Pseudomonas aeruginosa Biofilm Formation by Increasing M1 Macrophage-Mediated Anti-bacterial Activities.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1971}, pmid = {32903626}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa biofilms employ a variety of strategies to hijack the host immune defense system to achieve chronic infection. However, the bacterial components that are involved in this process are not yet fully understood. PcrV, a needle tip protein of the P. aeruginosa type III secretion system (T3SS), was downregulated during P. aeruginosa biofilm infection. The impaired expression of the P. aeruginosa pcrV gene is associated with attenuated immune activation and an increased percentage of M2 macrophages following P. aeruginosa biofilm infection. Treatment with exogenous PcrV produced from Escherichia coli elevated tissue inflammation and the percentage of M1 macrophages, resulting in reduction in the biofilm burden. Further analyses demonstrated that the potential of PcrV to induce classically activated M1 macrophages as evidenced by the increased production of proinflammatory cytokines and anti-bacterial mediators, including inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS), as well as increased phagocytosis of bacteria. Mechanistically, PcrV-mediated promotion of macrophage M1 polarization and phagocytosis occurs through the activation of mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways. Collectively, these findings reveal a potential role of PcrV in skewing host immune defense to promote P. aeruginosa biofilm infection and provide new insights into the therapeutic strategies for P. aeruginosa biofilm infection.}, } @article {pmid32901923, year = {2020}, author = {Begić, M and Josić, D}, title = {Biofilm formation and extracellular microvesicles-The way of foodborne pathogens toward resistance.}, journal = {Electrophoresis}, volume = {41}, number = {20}, pages = {1718-1739}, doi = {10.1002/elps.202000106}, pmid = {32901923}, issn = {1522-2683}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Bacteria/cytology/drug effects/pathogenicity ; Bacterial Toxins ; *Biofilms ; *Drug Resistance, Bacterial ; *Extracellular Vesicles ; Food Microbiology ; Food Safety ; Foodborne Diseases/*microbiology ; Humans ; Mice ; Virulence Factors ; }, abstract = {Almost all known foodborne pathogens are able to form biofilms as one of the strategies for survival under harsh living conditions, to ward off the inhibition and the disinfection during food production, transport and storage, as well as during cleaning and sanitation of corresponding facilities. Biofilms are communities where microbial cells live under constant intracellular interaction and communication. Members of the biofilm community are embedded into extracellular matrix that contains polysaccharides, DNA, lipids, proteins, and small molecules that protect microorganisms and enable their intercellular communication under stress conditions. Membrane vesicles (MVs) are produced by both Gram positive and Gram negative bacteria. These lipid membrane-enveloped nanoparticles play an important role in biofilm genesis and in communication between different biofilm members. Furthermore, MVs are involved in other important steps of bacterial life like cell wall modeling, cellular division, and intercellular communication. They also carry toxins and virulence factors, as well as nucleic acids and different metabolites, and play a key role in host infections. After entering host cells, MVs can start many pathologic processes and cause serious harm and cell death. Prevention and inhibition of both biofilm formation and shedding of MVs by foodborne pathogens has a very important role in food production, storage, and food safety in general. Better knowledge of biofilm formation and maintaining, as well as the role of microbial vesicles in this process and in the process of host cells' infection is essential for food safety and prevention of both food spoilage and host infection.}, } @article {pmid32901713, year = {2020}, author = {Sadid-Zadeh, R and Willis, J and Forgo, G and Haraszthy, V}, title = {Comparative Analysis of Biofilm Formation on Materials Used for the Fabrication of Implant-Supported Prostheses.}, journal = {Brazilian dental journal}, volume = {31}, number = {4}, pages = {380-384}, doi = {10.1590/0103-6440202003385}, pmid = {32901713}, issn = {1806-4760}, mesh = {Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis ; Surface Properties ; Titanium ; }, abstract = {The purpose of this study was to compare biofilm formation on materials used for the fabrication of implant-supported dental prostheses. Twenty discs (D=15 mm, H=3 mm) were fabricated from one of the following restorative materials: yttria tetragonal zirconia polycrystal (Y-TZP); commercially pure titanium (CP-Ti); or heat-cured polymethyl methacrylate (PMMA). Specimens were polished following standard protocols. A non-contact profilometer (NPFLEX, Bruker, UK) was used to assess the surface roughness of each disk; results were reported as Ra (µm). Five strains of Gram-negative bacteria frequently associated with peri-implantitis, Aggregatibacter actinomycetemcomitans, Candida. albicans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia, were cultured on hand-polished discs fabricated from heat-cured PMMA, Y-TZP, or CP-Ti to compare biofilm formation on each type of material. The results were reported as colony-forming units per milliliter (CFU/mL). One-way ANOVA and post hoc tests were used to compare surface roughness and bacterial colonization on the respective materials. Statistical significance was set at a = 0.05. Discs fabricated from Y-TZP had a significantly higher Ra value (350 ± 30 µm) than either PMMA, or CP-Ti discs. Discs fabricated from either Y-TZP and CP-Ti may exhibit less colonization by bacteria associated with peri-mucositis and peri-implantitis. Y-TZP and CP-Ti are suggested materials for fabrication of implant-supported prostheses, considering biofilm formation.}, } @article {pmid32901508, year = {2020}, author = {Rizzo, NN and Pottker, ES and Webber, B and Borges, KA and Duarte, SC and Levandowski, R and Ruschel, LR and Rodrigues, LB}, title = {Effect of two lytic bacteriophages against multidrug-resistant and biofilm-forming Salmonella Gallinarum from poultry.}, journal = {British poultry science}, volume = {61}, number = {6}, pages = {640-645}, doi = {10.1080/00071668.2020.1805724}, pmid = {32901508}, issn = {1466-1799}, mesh = {Animals ; *Bacteriophages ; Biofilms ; Chickens ; Poultry ; *Poultry Diseases ; *Salmonella Infections, Animal ; *Salmonella enterica ; }, abstract = {1. Salmonella Gallinarum (SG) infections cause fowl typhoid, which leads to important economic losses. Multidrug resistance (MDR) and the capacity for bacteria to form biofilms could play an important role in the persistence of SG in poultry flocks resulting in intermittent disease outbreaks. The aim of the following study was to assess the lytic activity of two new bacteriophages (Salmonella phages UPF_BP1 and UPF_BP2) against MDR and biofilm-forming SG. 2. Forty-six strains of SG, isolated in 2015, were characterised by antimicrobial resistance, biofilm formation profiles and susceptibility to two new bacteriophages. 3. Of these strains, 24% were multidrug resistant and more than 80% formed biofilm, with no statistical difference between incubation temperatures (42°C or 22°C). With regard to the lytic activity of the phages, 85% of strains were susceptible to at least one phage. Of these, 74% were lysed by both phages, including MDR and biofilm producing strains. 4. The use of salmonella phages UPF_BP1 and UPF_BP2 were shown to be promising alternatives for the biological control of fowl typhoid.}, } @article {pmid32900808, year = {2020}, author = {Seviour, T and Wong, LL and Lu, Y and Mugunthan, S and Yang, Q and Shankari, U and Bessarab, I and Liebl, D and Williams, RBH and Law, Y and Kjelleberg, S}, title = {Phase Transitions by an Abundant Protein in the Anammox Extracellular Matrix Mediate Cell-to-Cell Aggregation and Biofilm Formation.}, journal = {mBio}, volume = {11}, number = {5}, pages = {}, pmid = {32900808}, issn = {2150-7511}, mesh = {Ammonium Compounds/*metabolism ; Anaerobiosis ; Bacteria/classification/genetics/*metabolism ; Bacterial Physiological Phenomena/genetics ; Bacterial Proteins/*chemistry/isolation & purification/*metabolism ; Biofilms/*growth & development ; Biophysical Phenomena ; *Oxidation-Reduction ; }, abstract = {This study describes the first direct functional assignment of a highly abundant extracellular protein from a key environmental and biotechnological biofilm performing an anaerobic ammonium oxidation (anammox) process. Expression levels of Brosi_A1236, belonging to a class of proteins previously suggested to be cell surface associated, were in the top one percentile of all genes in the "Candidatus Brocadia sinica"-enriched biofilm. The Brosi_A1236 structure was computationally predicted to consist of immunoglobulin-like anti-parallel β-strands, and circular dichroism conducted on the isolated surface protein indicated that β-strands are the dominant higher-order structure. The isolated protein was stained positively by the β-sheet-specific stain thioflavin T, along with cell surface- and matrix-associated regions of the biofilm. The surface protein has a large unstructured content, including two highly disordered domains at its C terminus. The disordered domains bound to the substratum and thereby facilitated the adhesion of negatively charged latex microspheres, which were used as a proxy for cells. The disordered domains and isolated whole surface protein also underwent liquid-liquid phase separation to form liquid droplets in suspension. Liquid droplets of disordered protein wet the surfaces of microspheres and bacterial cells and facilitated their coalescence. Furthermore, the surface layer protein formed gels as well as ordered crystalline structures. These observations suggest that biophysical remodeling through phase transitions promotes aggregation and biofilm formation.IMPORTANCE By employing biophysical and liquid-liquid phase separation concepts, this study revealed how a highly abundant extracellular protein enhances the key environmental and industrial bioprocess of anaerobic ammonium oxidation (anammox). Extracellular proteins of environmental biofilms are understudied and poorly annotated in public databases. Understanding the function of extracellular proteins is also increasingly important for improving bioprocesses and resource recovery. Here, protein functions were assessed based on theoretical predictions of intrinsically disordered domains, known to promote adhesion and liquid-liquid phase separation, and available surface layer protein properties. A model is thus proposed to explain how the protein promotes aggregation and biofilm formation by extracellular matrix remodeling and phase transitions. This work provides a strong foundation for functional investigations of extracellular proteins involved in biofilm development.}, } @article {pmid32900803, year = {2020}, author = {Bosch, ME and Bertrand, BP and Heim, CE and Alqarzaee, AA and Chaudhari, SS and Aldrich, AL and Fey, PD and Thomas, VC and Kielian, T}, title = {Staphylococcus aureus ATP Synthase Promotes Biofilm Persistence by Influencing Innate Immunity.}, journal = {mBio}, volume = {11}, number = {5}, pages = {}, pmid = {32900803}, issn = {2150-7511}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; R01 AI125588/AI/NIAID NIH HHS/United States ; }, mesh = {ATP Synthetase Complexes/*genetics/*immunology/metabolism ; Animals ; Biofilms/*growth & development ; Cytokines/immunology ; Disease Models, Animal ; Host-Pathogen Interactions/*immunology ; *Immunity, Innate ; Macrophages/immunology/microbiology ; Mice ; Mice, Inbred C57BL ; Staphylococcus aureus/*enzymology/genetics/*immunology/pathogenicity ; }, abstract = {Staphylococcus aureus is a major cause of prosthetic joint infection (PJI), which is characterized by biofilm formation. S. aureus biofilm skews the host immune response toward an anti-inflammatory profile by the increased recruitment of myeloid-derived suppressor cells (MDSCs) that attenuate macrophage proinflammatory activity, leading to chronic infection. A screen of the Nebraska Transposon Mutant Library identified several hits in the ATP synthase operon that elicited a heightened inflammatory response in macrophages and MDSCs, including atpA, which encodes the alpha subunit of ATP synthase. An atpA transposon mutant (ΔatpA) had altered growth kinetics under both planktonic and biofilm conditions, along with a diffuse biofilm architecture that was permissive for leukocyte infiltration, as observed by confocal laser scanning microscopy. Coculture of MDSCs and macrophages with ΔatpA biofilm elicited significant increases in the proinflammatory cytokines interleukin 12p70 (IL-12p70), tumor necrosis factor alpha (TNF-α), and IL-6. This was attributed to increased leukocyte survival resulting from less toxin and protease production by ΔatpA biofilm as determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The enhanced inflammatory response elicited by ΔatpA biofilm was cell lysis-dependent since it was negated by polyanethole sodium sulfanate treatment or deletion of the major autolysin, Atl. In a mouse model of PJI, ΔatpA-infected mice had decreased MDSCs concomitant with increased monocyte/macrophage infiltrates and proinflammatory cytokine production, which resulted in biofilm clearance. These studies identify S. aureus ATP synthase as an important factor in influencing the immune response during biofilm-associated infection and bacterial persistence.IMPORTANCE Medical device-associated biofilm infections are a therapeutic challenge based on their antibiotic tolerance and ability to evade immune-mediated clearance. The virulence determinants responsible for bacterial biofilm to induce a maladaptive immune response remain largely unknown. This study identified a critical role for S. aureus ATP synthase in influencing the host immune response to biofilm infection. An S. aureus ATP synthase alpha subunit mutant (ΔatpA) elicited heightened proinflammatory cytokine production by leukocytes in vitro and in vivo, which coincided with improved biofilm clearance in a mouse model of prosthetic joint infection. The ability of S. aureus ΔatpA to augment host proinflammatory responses was cell lysis-dependent, as inhibition of bacterial lysis by polyanethole sodium sulfanate or a ΔatpAΔatl biofilm did not elicit heightened cytokine production. These studies reveal a critical role for AtpA in shaping the host immune response to S. aureus biofilm.}, } @article {pmid32897417, year = {2020}, author = {Yi, L and Jin, M and Li, J and Grenier, D and Wang, Y}, title = {Antibiotic resistance related to biofilm formation in Streptococcus suis.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {20}, pages = {8649-8660}, doi = {10.1007/s00253-020-10873-9}, pmid = {32897417}, issn = {1432-0614}, support = {31902309, 31772761//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Biofilms ; Drug Resistance, Microbial ; *Streptococcal Infections/drug therapy/veterinary ; *Streptococcus suis ; Swine ; Virulence ; }, abstract = {Streptococcus suis (S. suis) is an important zoonotic agent, which seriously impacts the pig industry and human health in various countries. Biofilm formation is likely contributing to the virulence and drug resistance in S. suis. A better knowledge of biofilm formation as well as to biofilm-dependent drug resistance mechanisms in S. suis can be of great significance for the prevention and treatment of S. suis infections. This literature review updates the latest scientific data related to biofilm formation in S. suis and its impact on drug tolerance and resistance.Key points• Biofilm formation is the important reasons for drug resistance of SS infections.• The review includes the regulatory mechanism of SS biofilm formation.• The review includes the drug resistance mechanisms of SS biofilm.}, } @article {pmid32897280, year = {2020}, author = {Li, X and Tsui, KH and Tsoi, JKH and Green, DW and Jin, XZ and Deng, YQ and Zhu, YM and Li, XG and Fan, Z and Cheung, GS}, title = {A nanostructured anti-biofilm surface widens the efficacy against spindle-shaped and chain-forming rod-like bacteria.}, journal = {Nanoscale}, volume = {12}, number = {36}, pages = {18864-18874}, doi = {10.1039/d0nr03809a}, pmid = {32897280}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; *Biofilms ; Porphyromonas gingivalis ; Streptococcus mutans ; }, abstract = {Current control of pathogenic bacteria at all biomaterial interfaces is poorly attuned to a broad range of disease-causing pathogens. Leading antimicrobial surface functionalization strategies with antimicrobial peptides (AMPs), defensins, have not shown their promised efficacy. One of the main problems is the lack of stability and swift clearance from the surface. Surface nanotopography bearing sharp protrusions is a non-chemical solution that is intrinsically stable and long-lasting. Previously, the geometrically ordered arrays of nanotipped spines repelled or rapidly ruptured bacteria that come into contact. The killing properties so far work on cocci and rod-like bacteria, but there is no validation of the efficacy of protrusional surfaces on pathogenic bacteria with different sizes and morphologies, thus broadening the utility of such surfaces to cover increasingly more disease entities. Here, we report a synthetic analogue of nanotipped spines with a pyramidal shape that show great effectiveness on species of bacteria with strongly contrasting shapes and sizes. To highlight this phenomenon in the field of dental applications where selective bacterial control is vital to the clinical success of biomaterial functions, we modified the poly(methyl)-methacrylate (PMMA) texture and tested it against Streptococcus mutans, Enterococcus faecalis, Porphyromonas gingivalis, and Fusobacterium nucleatum. These nanopyramids performed effectively at levels well above those of normal and roughened PMMA biomaterials for dentistry and a model material for general use in medicine and disease transmission in hospital environments.}, } @article {pmid32896958, year = {2020}, author = {Dong, J and Wang, B and Xiang, B and Yang, J and Gong, Z and Wang, Z and Huang, Y and Chen, L}, title = {Research on the effect of TiO2 nanotubes coated by gallium nitrate on Staphylococcus aureus-Escherichia coli biofilm formation.}, journal = {Journal of clinical laboratory analysis}, volume = {34}, number = {9}, pages = {e23417}, pmid = {32896958}, issn = {1098-2825}, support = {2019FE001//Basic research plan of Yunnan Province (Joint special fund of Kunming Medical University)/ ; (-143)//Basic research plan of Yunnan Province (Joint special fund of Kunming Medical University)/ ; }, mesh = {*Bacterial Adhesion ; Biofilms/drug effects/*growth & development ; Escherichia coli/drug effects/*growth & development ; Gallium/*chemistry ; Humans ; Nanotubes/*chemistry ; Staphylococcus aureus/drug effects/*growth & development ; Titanium/chemistry/*pharmacology ; }, abstract = {BACKGROUND: In clinical practice, the cases with bacterial infection caused by titanium implants and bacterial biofilm formation on the surface of titanium materials implanted into human body can often be observed. Thus, this study aimed to demonstrate whether the mixed biofilm of Staphylococcus aureus/Escherichia coli can be formed on the surface of titanium material through in vitro experiments and its formation rules.

METHODS: The titanium plates were put into the well containing S aureus or/and E coli. Bacterial adhesion and biofilm formation were analyzed by crystal violet, XTT method, confocal laser scanning microscopy, and scanning electron microscopy.

RESULTS: The results of bacterial adhesion in each group at 6-72 hours showed that the number of bacterial adhesion in each group was increased with the extension of time and reached to the highest level at 72 hours. Moreover, the biofilm structure in the S aureus-E coli group was significantly more complex than that of the simple S aureus group or E coli group, and the number of bacteria was also significantly increased in the S aureus-E coli group.

CONCLUSION: Those data provide a laboratory basis for the prevention and treatment of mixed infection of subsequent biological materials.}, } @article {pmid32896574, year = {2020}, author = {Silvestre, I and Borrego, MJ and Jordão, L}, title = {Biofilm formation by ST17 and ST19 strains of Streptococcus agalactiae.}, journal = {Research in microbiology}, volume = {171}, number = {8}, pages = {311-318}, doi = {10.1016/j.resmic.2020.08.001}, pmid = {32896574}, issn = {1769-7123}, mesh = {Biofilms/*growth & development ; Culture Media/metabolism ; Extracellular Polymeric Substance Matrix/chemistry ; Glucose ; Humans ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning ; Plasma ; Streptococcus agalactiae/*growth & development/ultrastructure ; Virulence Factors/metabolism ; }, abstract = {Bacterial biofilms are an important virulence factor with a vital role in evasion from the host immune system, colonization and infection. The aim of the present study was to evaluate in vitro the effects of three environmental factors (H[+], glucose and human plasma) in biofilm formation, by carrier and invasive Streptococcus agalactiae strains of ST17 and ST19 sequence types, including DNase producers and non-producers. Bacteria ability to assemble biofilms was classified based on crystal violet assay. Biofilm formation was also monitored by scanning electron microscopy. Depending on the growth medium used, each bacterial isolate could fit in different biofilm production categories. Our data showed that optimal conditions for S. agalactiae biofilm assembly were reached after 48 h incubation at pH 7.6 in the presence of glucose and inactivated human plasma. In the presence of inactivated human plasma, the biofilm biomass of ST19 strains experienced a higher increase than ST17 strains. The composition of the extracellular polymeric matrix of the three strongest biofilm producers (all from ST17) was accessed by enzymatic digestion of mature biofilms and proteins were shown to be the predominant component. The detailed identification of the extracellular protein components should contribute to the development of new therapeutic strategies to fight S. agalactiae infections.}, } @article {pmid32894779, year = {2020}, author = {Costa, RC and Souza, JGS and Bertolini, M and Retamal-Valdes, B and Feres, M and Barão, VAR}, title = {Extracellular biofilm matrix leads to microbial dysbiosis and reduces biofilm susceptibility to antimicrobials on titanium biomaterial: An in vitro and in situ study.}, journal = {Clinical oral implants research}, volume = {31}, number = {12}, pages = {1173-1186}, doi = {10.1111/clr.13663}, pmid = {32894779}, issn = {1600-0501}, support = {2018/04630-2//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; 304853/2018-6//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brazil (CAPES) [financial code 001]; and Conselho Nacional de Desenvolvimento Científico e Tecnológico-Brazil (CNPq)./ ; }, mesh = {Biofilms ; Dysbiosis ; *Extracellular Polymeric Substance Matrix ; Humans ; *Streptococcus mutans ; Titanium/pharmacology ; }, abstract = {OBJECTIVES: To test the role of exopolysaccharide (EPS) polymers matrix to modulate the composition/virulence of biofilms growing on titanium (Ti) surfaces, the effect on antibiotic susceptibility, and whether a dual-targeting therapy approach for disrupted EPS matrix could improve the antimicrobial effect.

MATERIALS AND METHODS: A microcosm biofilm model using human saliva as inoculum was used, and the microbial composition was assessed by checkerboard DNA-DNA hybridization. EPS-enriched biofilms virulence was tested using fibroblast monolayer. Povidone-iodine (PI) was used as EPS-targeting agent followed by amoxicillin + metronidazole antibiotic to reduce bacterial biomass using an in situ model.

RESULTS: An EPS-enriched environment, obtained by sucrose exposure, promoted bacterial accumulation and led to a dysbiosis on biofilms, favoring the growth of Streptococcus, Fusobacterium, and Campylobacter species and even strict anaerobic species related to peri-implant infections, such as Porphyromonas gingivalis and Tannerella forsythia (~3-fold increase). EPS-enriched biofilm transitioned from a commensal aerobic to a pathogenic anaerobic profile. EPS increased biofilm virulence promoting higher host cell damage and reduced antimicrobial susceptibility, but the use of a dual-targeting approach with PI pre-treatment disrupted EPS matrix scaffold, increasing antibiotic effect on in situ biofilms.

CONCLUSION: Altogether, our data provide new insights of how EPS matrix creates an environment that favors putative pathogens growth and shed light to a promising approach that uses matrix disruption as initial step to potentially improve implant-related infections treatment.}, } @article {pmid32894594, year = {2021}, author = {Jeffries, J and Thongsomboon, W and Visser, JA and Enriquez, K and Yager, D and Cegelski, L}, title = {Variation in the ratio of curli and phosphoethanolamine cellulose associated with biofilm architecture and properties.}, journal = {Biopolymers}, volume = {112}, number = {1}, pages = {e23395}, doi = {10.1002/bip.23395}, pmid = {32894594}, issn = {1097-0282}, support = {SGTP; NIH NHGRI T32HG000044/NH/NIH HHS/United States ; 2001189//National Science Foundation/ ; CAREER/PECASE Award 1453247//National Science Foundation/ ; SGTP; NIH NHGRI T32HG000044/NH/NIH HHS/United States ; }, mesh = {Bacterial Proteins/*chemistry ; *Biofilms ; Biomass ; Carbon-13 Magnetic Resonance Spectroscopy ; Cellulose/*chemistry ; Escherichia coli/isolation & purification/physiology ; Ethanolamines/chemistry ; Extracellular Matrix/*chemistry ; }, abstract = {Bacterial biofilms are communities of bacteria entangled in a self-produced extracellular matrix (ECM). Escherichia coli direct the assembly of two insoluble biopolymers, curli amyloid fibers, and phosphoethanolamine (pEtN) cellulose, to build remarkable biofilm architectures. Intense curiosity surrounds how bacteria harness these amyloid-polysaccharide composites to build biofilms, and how these biopolymers function to benefit bacterial communities. Defining ECM composition involving insoluble polymeric assemblies poses unique challenges to analysis and, thus, to comparing strains with quantitative ECM molecular correlates. In this work, we present results from a sum-of-the-parts [13] C solid-state nuclear magnetic resonance (NMR) analysis to define the curli-to-pEtN cellulose ratio in the isolated ECM of the E. coli laboratory K12 strain, AR3110. We compare and contrast the compositional analysis and comprehensive biofilm phenotypes for AR3110 and a well-studied clinical isolate, UTI89. The ECM isolated from AR3110 contains approximately twice the amount of pEtN cellulose relative to curli content as UTI89, revealing plasticity in matrix assembly principles among strains. The two parent strains and a panel of relevant gene mutants were investigated in three biofilm models, examining: (a) macrocolonies on agar, (b) pellicles at the liquid-air interface, and (c) biomass accumulation on plastic. We describe the influence of curli, cellulose, and the pEtN modification on biofilm phenotypes with power in the direct comparison of these strains. The results suggest that curli more strongly influence adhesion, while pEtN cellulose drives cohesion. Their individual and combined influence depends on both the biofilm modality (agar, pellicle, or plastic-associated) and the strain itself.}, } @article {pmid32894492, year = {2021}, author = {Sandala, J and Gunn, JS}, title = {In Vitro Evaluation of Anti-biofilm Agents Against Salmonella enterica.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2182}, number = {}, pages = {127-139}, doi = {10.1007/978-1-0716-0791-6_12}, pmid = {32894492}, issn = {1940-6029}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Salmonella enterica/*drug effects ; }, abstract = {Salmonella enterica is able to establish robust adherent communities called biofilms that allow for long-term colonization of both biotic and abiotic surfaces. These biofilm communities pose a significant challenge to successful eradication of the bacteria from contaminated surfaces and the infected host, as entry into the biofilm phenotype confers the bacterial population with tolerance to a variety of environmental and therapeutic insults to which it would otherwise be susceptible. The identification of antimicrobial strategies that specifically target the Salmonella biofilm state is therefore of great importance in order to both prevent and treat biofilm-mediated disease. Here, we provide detailed methods for the in vitro cultivation of Salmonella biofilms that can easily be scaled up for use in high-throughput screening of candidate anti-biofilm agents. These assays may also be utilized to further characterize the inhibitory and/or disruptive capabilities of lead anti-biofilm agents, as well as to identify combination treatments that demonstrate enhanced anti-biofilm effects. Furthermore, the assays may be slightly modified (e.g., optimal growth conditions) to evaluate other bacterial genera.}, } @article {pmid32894030, year = {2020}, author = {Yu, L and Wang, H and Han, X and Li, W and Xue, M and Qi, K and Chen, X and Ni, J and Deng, R and Shang, F and Xue, T}, title = {The two-component system, BasSR, is involved in the regulation of biofilm and virulence in avian pathogenic Escherichia coli.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {49}, number = {6}, pages = {532-546}, doi = {10.1080/03079457.2020.1781791}, pmid = {32894030}, issn = {1465-3338}, mesh = {Animals ; Biofilms/*growth & development ; Chickens/*microbiology ; Computational Biology ; Escherichia coli/genetics/growth & development/*pathogenicity ; Escherichia coli Infections/microbiology/*veterinary ; Gene Expression Profiling/veterinary ; Mutation ; Poultry Diseases/*microbiology ; Virulence ; Virulence Factors/*genetics ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is a subgroup of extra-intestinal pathogenic E. coli (ExPEC) strains that cause avian colibacillosis, resulting in significant economic losses to the poultry industry worldwide. It has been reported that a few two-component signal transduction systems (TCS) participate in the regulation of the virulence factors of APEC infection. In this study, a basSR-deficient mutant strain was constructed from its parent strain APECX40 (WT), and high-throughput sequencing (RNA-seq) was performed to analyse the transcriptional profile of WT and its mutant strain XY1. Results showed that the deletion of basSR down-regulated the transcript levels of a series of biofilm- and virulence-related genes. Results of biofilm formation assays and bird model experiments indicated that the deletion of basSR inhibited biofilm formation in vitro and decreased bacterial virulence and colonization in vivo. In addition, electrophoretic mobility shift assays confirmed that the BasR protein could bind to the promoter regions of several biofilm- and virulence-related genes, including ais, opgC and fepA. This study suggests that the BasSR TCS might be a global regulator in the pathogenesis of APEC infection. RESEARCH HIGHLIGHTS Transcriptional profiling showed that BasSR might be a global regulator in APEC. BasSR increases APEC pathogenicity in vivo. BasSR positively regulates biofilm- and the virulence-associated genes. BasSR can bind to the promoter regions of virulence-associated genes ais, opgC and fepA.}, } @article {pmid32893500, year = {2020}, author = {Pan, M and Lu, C and Zheng, M and Zhou, W and Song, F and Chen, W and Yao, F and Liu, D and Cai, J}, title = {Unnatural Amino-Acid-Based Star-Shaped Poly(l-Ornithine)s as Emerging Long-Term and Biofilm-Disrupting Antimicrobial Peptides to Treat Pseudomonas aeruginosa-Infected Burn Wounds.}, journal = {Advanced healthcare materials}, volume = {9}, number = {19}, pages = {e2000647}, doi = {10.1002/adhm.202000647}, pmid = {32893500}, issn = {2192-2659}, mesh = {Amino Acids ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Burns/drug therapy ; Mice ; Microbial Sensitivity Tests ; Ornithine ; Pore Forming Cytotoxic Proteins ; *Pseudomonas aeruginosa ; }, abstract = {Peptide-based antimicrobial materials are recognized as promising alternatives to antibiotics to circumvent the emergence of antibiotic-resistant bacteria or to combat multiple resistant bacteria by targeting the bacterial cell membrane. The components and conformations of antimicrobial peptides are extensively explored to achieve broad-spectrum and effective antimicrobial activity. Here, star-shaped antimicrobial polypeptides are fabricated by employing homologs of poly(l-lysine)s (i.e., poly(l-ornithine)s, poly(l-lysine)s, and poly(l-α,ζ-diaminoheptylic acid)s) with the aim of modulating their charge/hydrophobicity balance and rationalizing their structure-antimicrobial property relationships. The in vitro antibacterial investigation reveals that unnatural amino-acid-based star-shaped poly(l-ornithine)s have remarkable proteolytic stability, excellent biofilm-disrupting capacity, and broad-spectrum antimicrobial activity, even against difficult-to-kill Gram-negative Pseudomonas aeruginosa. Furthermore, star-shaped poly(l-ornithine)s significantly reduce the microbial burden and improve the burn wound healing of mouse skin infected with P. aeruginosa. These results demonstrate that unnatural amino-acid-based star-shaped poly(l-ornithine)s can serve as emerging long-term and biofilm-disrupting antimicrobial agents to treat biofilm-related infections in burn, especially caused by notorious P. aeruginosa.}, } @article {pmid32892026, year = {2020}, author = {Cheng, P and Chu, R and Zhang, X and Song, L and Chen, D and Zhou, C and Yan, X and Cheng, JJ and Ruan, R}, title = {Screening of the dominant Chlorella pyrenoidosa for biofilm attached culture and feed production while treating swine wastewater.}, journal = {Bioresource technology}, volume = {318}, number = {}, pages = {124054}, doi = {10.1016/j.biortech.2020.124054}, pmid = {32892026}, issn = {1873-2976}, mesh = {Animals ; Biofilms ; Biomass ; *Chlorella ; Lipids ; *Microalgae ; Swine ; Wastewater/analysis ; }, abstract = {This research 12 microalgal species were screened for biofilm attached culture in the treatment of anaerobically digested swine wastewater (ADSW). The influence of ADSW on biomass productivity and removal efficiencies were evaluated using biofilm attached culture with the selected Chlorella pyrenoidosa. The variation of nutritional components from algal cells were further analysed to evaluate the potential applications of C. pyrenoidosa. The results showed that C. pyrenoidosa had the highest tolerance to ADSW, and the highest removal efficiencies for wastewater pollutants were reached when cultured in 5 times diluted ADSW. These test conditions resulted in an algal cell biomass composed of 57.30% proteins, 14.87% extracellular polysaccharide, 3.08% crude fibre, 5.57% crude ash, 2.85% moisture. Amino acids in proteins contained 21.73% essential amino acids and the EAA/NEAA value was 0.64. The essential amino acid score indicates that the selected C. pyrenoidosa could be a good protein source for feed addition.}, } @article {pmid32891907, year = {2020}, author = {Bunse, P and Orschler, L and Agrawal, S and Lackner, S}, title = {WITHDRAWN: Membrane Aerated Biofilm Reactors for mainstream partial nitritation / anammox: Experiences using real municipal wastewater.}, journal = {Water research}, volume = {186}, number = {}, pages = {116351}, doi = {10.1016/j.watres.2020.116351}, pmid = {32891907}, issn = {1879-2448}, mesh = {*Biofilms ; *Wastewater ; }, abstract = {The Publisher regrets that this article is an accidental duplication of a published article, http://dx.doi.org/10.1016/j.wroa.2020.100066. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.}, } @article {pmid32891016, year = {2020}, author = {White, JK and Nielsen, JL and Larsen, CM and Madsen, AM}, title = {Impact of dust on airborne Staphylococcus aureus' viability, culturability, inflammogenicity, and biofilm forming capacity.}, journal = {International journal of hygiene and environmental health}, volume = {230}, number = {}, pages = {113608}, doi = {10.1016/j.ijheh.2020.113608}, pmid = {32891016}, issn = {1618-131X}, mesh = {Animals ; Biofilms ; Dust ; Farms ; *Staphylococcal Infections ; *Staphylococcus aureus ; Swine ; }, abstract = {Staphylococcus aureus is an opportunistic pathogen associated with soft-tissue infections commonly encountered in indoor and farm environments as a component of airborne dust, which can potentially deposit in the respiratory tracts of workers and residents. However, knowledge regarding the survival and inflammatory potential of S. aureus in airborne dust has not been described. The objective of this study was to obtain knowledge on whether the presence of dust during aerosolisation affects the culturability (ability to grow on agar plates), their biofilm forming capacity, viability (using a viability qPCR), and inflammatory potential (using a human granulocyte based assay), and whether time from aerosolisation to subsequent analyses (the resting time) affects these. Aerosols containing S. aureus (DSM6148) in the presence of sterilised airborne dust from a pig farm were found to have higher culturability, viability, inflammatory potential, and ability to form biofilm compared with S. aureus aerosols generated without airborne dust. When aerosols of S. aureus were generated without dust, they showed a reduction in the culturability, as well as the biofilm forming capacity and an extended resting time was associated with a reduction in culturability, and biofilm forming capacity. In contrast, no differences in the viability were observed in samples with different resting times. The lack of a significant effect of different resting times on viability, and the significant effect on culturability, suggests that the stresses of aerosolisation may induce a viable, but not culturable (VBNC) state in S. aureus. A synergistic effect was found between S. aureus and dust concerning their ability to induce inflammation. In conclusion presence of airborne dust during aerosolisation of S. aureus affects the culturability, biofilm forming capacity, and inflammatory potential, but not the viability of S. aureus. This is of importance in relation to hygiene as well as how exposure to S. aureus is measured.}, } @article {pmid32889579, year = {2021}, author = {Sari, S and Koçak, E and Kart, D and Özdemir, Z and Acar, MF and Sayoğlu, B and Karakurt, A and Dalkara, S}, title = {Azole derivatives with naphthalene showing potent antifungal effects against planktonic and biofilm forms of Candida spp.: an in vitro and in silico study.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {24}, number = {1}, pages = {93-102}, pmid = {32889579}, issn = {1618-1905}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Azoles/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/genetics/physiology ; Candidiasis/drug therapy/*microbiology ; Drug Resistance, Fungal ; Humans ; Microbial Sensitivity Tests ; Naphthalenes/chemistry/pharmacology ; Plankton/drug effects/genetics/physiology ; }, abstract = {Candida infections pose a serious public health threat due to increasing drug resistance. Azoles are first-line antifungal drugs for fungal infections. In this study, we tested an in-house azole collection incorporating naphthalene ring to find hits against planktonic and biofilm forms of resistant Candida spp. In the collection, potent derivatives were identified against the susceptible strains of Candida with minimum inhibitory concentration (MIC) values lower than those of the reference drug, fluconazole. MIC values of 0.125 μg/ml against C. albicans, 0.0625 μg/ml against C. parapsilosis, and 2 μg/ml against C. krusei, an intrinsically azole-resistant non-albicans Candida, were obtained. Some of the derivatives were highly active against fluconazole-resistant clinical isolate of C. tropicalis. Inhibition of C. albicans biofilms was also observed at 4 μg/ml similar as amphotericin B, the reference drug known for its antibiofilm activity. Through molecular docking studies, affinities and key interactions of the compounds with fungal lanosterol 14α-demethylase (CYP51), the target enzyme of azoles, were predicted. The interactions of imidazole with heme cofactor and of the naphthalene with Tyr118 were highlighted in line with the literature data. As a result, this study proves the importance of naphthalene for the antifungal activity of azoles against Candida spp. in both planktonic and biofilm forms.}, } @article {pmid32889121, year = {2020}, author = {Aydin, S and Can, K}, title = {Pyophage cocktail for the biocontrol of membrane fouling and its effect in aerobic microbial biofilm community during the treatment of antibiotics.}, journal = {Bioresource technology}, volume = {318}, number = {}, pages = {123965}, doi = {10.1016/j.biortech.2020.123965}, pmid = {32889121}, issn = {1873-2976}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; *Biofouling ; Bioreactors ; Membranes, Artificial ; Wastewater ; }, abstract = {Membrane bioreactor systems face an inevitable challenge that is biofouling, which not only hinders the operation of the system, but also poses an environmental and medical concern caused by the increased antibiotic resistance in bacterial biofilms. This study investigates the disruption of membrane fouling using bacteriophage cocktail (Pyophage) in an aerobic membrane bioreactor for treatment of wastewater containing high non-lethal concentration of erythromycin, tetracycline and sulfamethoxazole, while also considering the effect of the cocktail on performance. The results indicate that Pyophage cocktail contributes significantly to the decrease (45%) in transmembrane pressure while also suppressing biofilm-producing bacteria compared to the control reactors. It also reconstructed biodegradation mechanism of antibiotics especially increasing the relative abundance of gram-negative bacteria by enhancement the removal rate of erythromycin and sulfamethoxazole from the aerobic system to 99%.}, } @article {pmid32887330, year = {2020}, author = {Zhou, W and Peng, X and Zhou, X and Bonavente, A and Weir, MD and Melo, MAS and Imazato, S and Oates, TW and Cheng, L and Xu, HHK}, title = {Novel Nanocomposite Inhibiting Caries at the Enamel Restoration Margins in an In Vitro Saliva-Derived Biofilm Secondary Caries Model.}, journal = {International journal of molecular sciences}, volume = {21}, number = {17}, pages = {}, pmid = {32887330}, issn = {1422-0067}, support = {81372889//National Natural Science Foundation of China/ ; 2017HH0008//International Science and Technology Cooperation of Sichuan/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Calcium Phosphates/*pharmacology ; Cattle ; Dental Caries/microbiology/pathology/*prevention & control ; Dental Enamel/*drug effects/microbiology/pathology ; Disease Models, Animal ; Hardness ; In Vitro Techniques ; Nanocomposites/*chemistry ; Saliva/*microbiology ; }, abstract = {Secondary caries often occurs at the tooth-composite margins. This study developed a novel bioactive composite containing DMAHDM (dimethylaminohexadecyl methacrylate) and NACP (nanoparticles of amorphous calcium phosphate), inhibiting caries at the enamel restoration margins in an in vitro saliva-derived biofilm secondary caries model for the first time. Four composites were tested: (1) Heliomolar nanocomposite, (2) 0% DMAHDM + 0% NACP, (3) 3% DMAHDM + 0% NACP, (D) 3% DMAHDM + 30% NACP. Saliva-derived biofilms were tested for antibacterial effects of the composites. Bovine enamel restorations were cultured with biofilms, Ca and P ion release of nanocomposite and enamel hardness at the enamel restoration margins was measured. Incorporation of DMAHDM and NACP into composite did not affect the mechanical properties (p > 0.05). The biofilms' CFU (colony-forming units) were reduced by 2 logs via DMAHDM (p < 0.05). Ca and P ion release of the nanocomposite was increased at cariogenic low pH. Enamel hardness at the margins for DMAHDM group was 25% higher than control (p < 0.05). With DMAHDM + NACP, the enamel hardness was the greatest and about 50% higher than control (p < 0.05). Therefore, the novel composite containing DMAHDM and NACP was strongly antibacterial and inhibited enamel demineralization, resulting in enamel hardness at the margins under biofilms that approached the hardness of healthy enamel.}, } @article {pmid32887236, year = {2020}, author = {Paduszynska, MA and Greber, KE and Paduszynski, W and Sawicki, W and Kamysz, W}, title = {Activity of Temporin A and Short Lipopeptides Combined with Gentamicin against Biofilm Formed by Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32887236}, issn = {2079-6382}, abstract = {The formation of biofilms on biomaterials causes biofilm-associated infections. Available treatments often fail to fight the microorganisms in the biofilm, creating serious risks for patient well-being and life. Due to their significant antibiofilm activities, antimicrobial peptides are being intensively investigated in this regard. A promising approach is a combination therapy that aims to increase the efficacy and broaden the spectrum of antibiotics. The main goal of this study was to evaluate the antimicrobial efficacy of temporin A and the short lipopeptides (C10)2-KKKK-NH2 and (C12)2-KKKK-NH2 in combination with gentamicin against biofilm formed by Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA). Peptides were synthesized with solid-phase temperature-assisted synthesis methodology. The minimum inhibitory concentrations (MICs), fractional inhibitory concentrations (FICs), minimum biofilm eradication concentrations (MBECs), and the influence of combinations of compounds with gentamicin on bacterial biofilm were determined for reference strains of SA (ATCC 25923) and PA (ATCC 9027). The peptides exhibited significant potential to enhance the antibacterial activity of gentamicin against SA biofilm, but there was no synergy in activity against planktonic cells. The antibiotic applied alone demonstrated strong activity against planktonic cells and poor effectiveness against SA biofilm. Biofilm formed by PA was much more sensitive to gentamicin, but some positive influences of supplementation with peptides were noticed. The results of the performed experiments suggest that the potential application of peptides as adjuvant agents in the treatment of biofilm-associated infections should be studied further.}, } @article {pmid32886494, year = {2020}, author = {Zhang, B and Yu, P and Wang, Z and Alvarez, PJJ}, title = {Hormetic Promotion of Biofilm Growth by Polyvalent Bacteriophages at Low Concentrations.}, journal = {Environmental science & technology}, volume = {54}, number = {19}, pages = {12358-12365}, doi = {10.1021/acs.est.0c03558}, pmid = {32886494}, issn = {1520-5851}, mesh = {*Bacteriophages/genetics ; Biofilms ; *Biofouling ; Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {Interactions between bacteriophages (phages) and biofilms are poorly understood despite their broad ecological and water quality implications. Here, we report that biofilm exposure to lytic polyvalent phages at low concentrations (i.e., 10[2]-10[4] phages/mL) can counterintuitively promote biofilm growth and densification (corroborated by confocal laser scanning microscopy (CLSM)). Such exposure hormetically upregulated quorum sensing genes (by 4.1- to 24.9-fold), polysaccharide production genes (by 3.7- to 9.3-fold), and curli synthesis genes (by 4.5- to 6.5-fold) in the biofilm-dwelling bacterial hosts (i.e., Escherichia coli and Pseudomonas aeruginosa) relative to unexposed controls. Accordingly, the biofilm matrix increased its polysaccharide and extracellular DNA content relative to unexposed controls (by 41.8 ± 2.3 and 81.4 ± 2.2%, respectively), which decreased biofilm permeability and increased structural integrity. This contributed to enhanced resistance to disinfection with chlorine (bacteria half-lives were 6.08 ± 0.05 vs 3.91 ± 0.03 min for unexposed controls) and to subsequent phage infection (biomass removal was 18.2 ± 1.2 vs 32.3 ± 1.2% for unexposed controls), apparently by mitigating diffusion of these antibacterial agents through the biofilm. Overall, low concentrations of phages reaching a biofilm may result in unintended biofilm stimulation, which might accelerate biofouling, biocorrosion, or other biofilm-related water quality problems.}, } @article {pmid32884912, year = {2020}, author = {Sen, S and Borah, SN and Bora, A and Deka, S}, title = {Rhamnolipid exhibits anti-biofilm activity against the dermatophytic fungi Trichophyton rubrum and Trichophyton mentagrophytes.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {27}, number = {}, pages = {e00516}, pmid = {32884912}, issn = {2215-017X}, abstract = {Dermatophytes are responsible for a majority of fungal infections in humans and other vertebrates, causing dermatophytosis. Treatment failures are often associated with biofilm formation, making dermatophytes resistant to antifungals. In this study, effects of a rhamnolipid (RL-SS14) produced by Pseudomonas aeruginosa SS14 on planktonic cells of Trichophyton rubrum and Trichophyton mentagrophytes, their biofilm formation, and disruption of mature biofilms were assessed. The composition of RL-SS14 was analysed using FTIR, HPLC-ESI-MS, and GC-MS. Minimum inhibitory concentrations against the planktonic forms of T. rubrum and T. mentagrophytes were 0.5 mg/mL and 0.125 mg/mL, respectively. Crystal-violet (biofilm biomass) and safranin (extracellular matrix) staining revealed that RL-SS14 significantly inhibited biofilm formation and also reduced preformed biofilms in a dose-dependent manner. Microscopic visualization of treated biofilms via SEM, AFM, and CLSM revealed marked morphological damage, cell death, and reduced extracellular matrix. The results indicate the potential of RL-SS14 as an anti-biofilm agent against dermatophytes.}, } @article {pmid32884095, year = {2020}, author = {Irshad, MS and Arshad, N and Ahmed, I and Abbasi, MS and Idrees, M and Ahmad, S and Sharaf, M and Asghar, MS and Zaindin, M}, title = {Low-cost green recyclable biomaterial for energy-dependent electrical switching and intact biofilm with antibacterial properties.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {14600}, pmid = {32884095}, issn = {2045-2322}, abstract = {A highly cost-effective recycled biomaterial extracted from lime peel has been made biocompatible and has been coated on a commercial fluorine-doped tin oxide (FTO) substrate of glass using the spin coating method. Structural, morphologic, electronic, and antibacterial measurements were thoroughly characterized as a green biomaterial thin film using X-rays (XRD), PL, FTIR, Raman, SEM, HRTEM, AFM, I-V, and antibacterial diffusion techniques. The comprehensive analysis of structures of recyclable waste in the form of lime peel extract (LPE) as thin films showed the crystalline cellulose structure that corresponds to the lattice fringe (0.342 nm) exposed by HRTEM. The K[+1] interstitial active sites or vacancies in LPE/FTO thin films are confirmed by the PL spectra that show important evidence about conduction mechanisms, and hence facilitates Ag[+1] ion migration from the top to the bottom electrode. The AFM investigations revealed the minor surface roughness (169.61 nm) of the LPE/FTO film, which controls the current leakage that is associated with surface defects. The designed memory cell (Ag/LPE/FTO) exhibits stable, reproducible electrical switching under low operational voltage and is equipped with excellent retention over 5 × 10[3] s. Furthermore, owing to presence of flavonoids and their superior antioxidant nature, lime peel extract powder shows tremendous antimicrobial activity against gram-positive and Gram-negative bacterial strains.}, } @article {pmid32883934, year = {2020}, author = {Das, AK and Dudeja, M and Kohli, S and Ray, P and Singh, M and Kaur, PS}, title = {Biofilm synthesis and other virulence factors in multidrug-resistant uropathogenic enterococci isolated in Northern India.}, journal = {Indian journal of medical microbiology}, volume = {38}, number = {2}, pages = {200-209}, doi = {10.4103/ijmm.IJMM_19_355}, pmid = {32883934}, issn = {1998-3646}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Carbon-Oxygen Ligases/genetics ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial ; Enterococcus/drug effects/isolation & purification/metabolism/pathogenicity ; Enterococcus faecalis/drug effects/isolation & purification/metabolism/pathogenicity ; Enterococcus faecium/drug effects/isolation & purification/metabolism/*pathogenicity ; Genes, Bacterial ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; India ; Microbial Sensitivity Tests ; Urinary Tract Infections/*microbiology ; Vancomycin Resistance/genetics ; Vancomycin-Resistant Enterococci/genetics/isolation & purification/*pathogenicity/physiology ; Virulence/genetics ; Virulence Factors/*biosynthesis/genetics ; }, abstract = {PURPOSE: Enterococci express high degree of resistance towards wide range of antibiotics. Production of biofilm and many virulence factors along with drug resistance makes it difficult to eradicate the infection from urinary tract. The present study detected the expression of such factors including biofilm production by multidrug-resistant (MDR) enterococci.

MATERIALS AND METHODS: Drug susceptibility of 103 uropathogenic enterococci was performed followed by estimation of minimum inhibitory concentration of high-level gentamicin and vancomycin by microbroth dilution method. Vancomycin-resistant genes were detected by multiplex polymerase chain reaction. Production of virulence factors such as haemagglutination, caseinase, lipase, gelatinase, haemolysin and β-lactamase was detected by phenotypic methods in MDR strains. Biofilm production was detected by calcofluor-white fluorescence staining and semi-quantitative adherence assay.

RESULTS: 45% and 18.4% of the isolates were high-level gentamicin-resistant and vancomycin-resistant enterococci (VRE), respectively. vanA gene was detected in 14 and vanB gene in 5 strains. Biofilm, caseinase and gelatinase were the most expressed virulence factor. Expression of caseinase, gelatinase and lipase was significantly higher in Enterococcus faecalis (P < 0.05). Expression of haemagglutination, gelatinase and haemolysin among the vancomycin-resistant isolates was significantly higher (P < 0.05).

CONCLUSION: VanA and vanB are the prevalent genotypes responsible for vancomycin resistance. The high prevalence of MDR enterococcal strains producing biofilm and virulence determinants raises concern. asa1, hyl, esp, gelE, cyl and other genes are known to express these factors and contribute to biofilm formation. Most uropathogenic enterococci expressed biofilm at moderate level and can be detected effectively by calcofluor-white staining. No correlation was noted between vancomycin resistance and biofilm production.}, } @article {pmid32883093, year = {2020}, author = {Pinel, ISM and Kim, LH and Proença Borges, VR and Farhat, NM and Witkamp, GJ and van Loosdrecht, MCM and Vrouwenvelder, JS}, title = {Effect of phosphate availability on biofilm formation in cooling towers.}, journal = {Biofouling}, volume = {36}, number = {7}, pages = {800-815}, doi = {10.1080/08927014.2020.1815011}, pmid = {32883093}, issn = {1029-2454}, mesh = {*Biofilms ; *Biofouling/prevention & control ; Biomass ; Membranes, Artificial ; Phosphates ; *Water Purification ; }, abstract = {Phosphate limitation has been suggested as a preventive method against biofilms. P-limited feed water was studied as a preventive strategy against biofouling in cooling towers (CTs). Three pilot-scale open recirculating CTs were operated in parallel for five weeks. RO permeate was fed to the CTs (1) without supplementation (reference), (2) with supplementation by biodegradable carbon (P-limited) and (3) with supplementation of all nutrients (non-P-limited). The P-limited water contained ≤10 µg PO4 l[-1]. Investigating the CT-basins and coupons showed that P-limited water (1) did not prevent biofilm formation and (2) resulted in a higher volume of organic matter per unit of active biomass compared with the other CTs. Exposure to external conditions and cycle of concentration were likely factors that allowed a P concentration sufficient to cause extensive biofouling despite being the limiting compound. In conclusion, phosphate limitation in cooling water is not a suitable strategy for CT biofouling control.}, } @article {pmid32882535, year = {2020}, author = {Turrini, P and Tescari, M and Visaggio, D and Pirolo, M and Lugli, GA and Ventura, M and Frangipani, E and Visca, P}, title = {The microbial community of a biofilm lining the wall of a pristine cave in Western New Guinea.}, journal = {Microbiological research}, volume = {241}, number = {}, pages = {126584}, doi = {10.1016/j.micres.2020.126584}, pmid = {32882535}, issn = {1618-0623}, mesh = {Acidobacteria/classification/genetics/isolation & purification ; Actinobacteria/classification/genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*classification/*drug effects ; Biofilms/*growth & development ; Caves/*microbiology ; DNA, Bacterial/genetics ; Drug Resistance, Bacterial/genetics ; Firmicutes/classification/genetics/isolation & purification ; Metagenome/genetics ; Microbial Sensitivity Tests ; Microbiota/*genetics ; New Guinea ; Proteobacteria/classification/genetics/isolation & purification ; Pseudomonas/classification/genetics/isolation & purification ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Soil Microbiology ; }, abstract = {Caves are extreme environments inhabited by microbial communities adapted to thrive oligotrophic conditions. Cave microbes are organised in complex ecological networks and have developed survival strategies involving the production and release of a large variety of secondary metabolites, including antibiotic-like compounds. In this study, the structure and the metabolic features of a biofilm-like microbial community lining the walls of a pristine karst cavity (the Yumugi river cave) located in a remote region of the Western New Guinea were investigated. 16S rRNA and shotgun sequence analyses highlighted the prevalence of chemoorganotrophic phyla (Proteobacteria, Actinobacteria, Firmicutes and Acidobacteria), consistent with metabolic predictions inferred from the cave metagenome analysis. Few clinically relevant antimicrobial resistance genes were detected. A culture-based approach allowed the isolation of some heterotrophic members of the bacterial community, and antimicrobial susceptibility testing revealed an overall high level of resistance to different antimicrobials classes. Isolates presumptively representing new uncharacterized members of genus Pseudomonas displayed interesting antibiotic properties against Gram-positive indicator strains. Our work supports the hypothesis that caves represent a reservoir for new bacterial species and drug discovery research.}, } @article {pmid32882442, year = {2020}, author = {Mirzaie, A and Peirovi, N and Akbarzadeh, I and Moghtaderi, M and Heidari, F and Yeganeh, FE and Noorbazargan, H and Mirzazadeh, S and Bakhtiari, R}, title = {Preparation and optimization of ciprofloxacin encapsulated niosomes: A new approach for enhanced antibacterial activity, biofilm inhibition and reduced antibiotic resistance in ciprofloxacin-resistant methicillin-resistance Staphylococcus aureus.}, journal = {Bioorganic chemistry}, volume = {103}, number = {}, pages = {104231}, doi = {10.1016/j.bioorg.2020.104231}, pmid = {32882442}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/chemistry/*pharmacology ; Drug Carriers/chemistry ; Drug Liberation ; Drug Resistance, Multiple, Bacterial/*drug effects ; Humans ; Liposomes/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Microbial Sensitivity Tests ; }, abstract = {Ciprofloxacin is an alternative to vancomycin for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The objective of this study was to optimization of niosomes encapsulated ciprofloxacin and evaluate their antibacterial and anti-biofilm efficacies against ciprofloxacin-resistant methicillin-resistant S. aureus (CR-MRSA) strains. Formulation of niosomes encapsulated ciprofloxacin were optimized by changing the proportions of Tween 60, Span 60, and cholesterol. The optimized ciprofloxacin encapsulated niosomal formulations based on Span 60 and Tween 60 were prepared and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The SEM and TEM results showed that the formulation of niosomes encapsulated ciprofloxacin were spherical with a size between 50 and 150 nm. The prepared niosomal formulations showed high storage stability up to 30 days with the slight change in size and drug entrapment during the storage, making them good candidates for drug delivery systems. Optimum niosome encapsulated ciprofloxacin enhanced antibacterial activity against CR-MRSA strains via reduction in minimum inhibitory concentration (MIC) value and inhibited significantly biofilm formation. Niosome encapsulated ciprofloxacin down-regulated the expression of icaB biofilm formation gene. Our results showed that encapsulating ciprofloxacin in niosomes is a promising approach to enhanced antibacterial activity, biofilm inhibition and reduced resistance to antibiotic in CR-MRSA strains.}, } @article {pmid32881183, year = {2021}, author = {Gharieb, R and Saad, M and Abdallah, K and Khedr, M and Farag, E and Abd El-Fattah, A}, title = {Insights on toxin genotyping, virulence, antibiogram profiling, biofilm formation and efficacy of disinfectants on biofilms of Clostridium perfringens isolated from poultry, animals and humans.}, journal = {Journal of applied microbiology}, volume = {130}, number = {3}, pages = {819-831}, doi = {10.1111/jam.14838}, pmid = {32881183}, issn = {1365-2672}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Toxins/*genetics ; Biofilms/*drug effects/growth & development ; Chickens/microbiology ; Clostridium Infections/microbiology ; Clostridium perfringens/drug effects/genetics/*isolation & purification/physiology ; Disinfectants/*pharmacology ; Drug Resistance, Multiple, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Poultry/microbiology ; Virulence/genetics ; }, abstract = {AIMS: This study aimed to determine the toxin genotypes, virulence determinants and antibiogram of Clostridium perfringens isolated from poultry, animals and humans. Biofilm formation and the efficacy of disinfectants on C. perfringens biofilms were studied.

METHODS AND RESULTS: Thirty C. perfringens isolates (20 clinical and 10 from chicken carcasses) were genotyped by PCR and all isolates were genotype A (cpa+). The overall prevalence of cpe, cpb2, netB and tpeL virulence genes was 6·7, 56·7, 56·7 and 36·7% respectively. Twenty-one isolates (70%) were multidrug-resistant, 8 (26·7%) were extensive drug-resistant and one isolate (3·3%) was pan drug-resistant. The average multiple antibiotic resistance index was 0·7. Biofilms were produced by 63·3% of C. perfringens isolates and categorized as weak (36·7%), moderate (16·7%) and strong (10%). Sodium hypochlorite caused significant reduction in C. perfringens biofilms (P < 0·0001).

CONCLUSIONS: All C. perfringens strains in this study were type A, resistant to multiple antibiotics and most of them were biofilm producers. Sodium hypochlorite showed higher efficacy in reducing C. perfringens biofilms.

This study reported the efficacy of disinfectants in reducing C. perfringens biofilms of economic and public health concern and recommends application on surfaces in farms, food processing plants and slaughterhouses.}, } @article {pmid32881009, year = {2020}, author = {Banerjee, A and Batabyal, K and Singh, AD and Joardar, SN and Dey, S and Isore, DP and Sar, TK and Dutta, TK and Bandyopadhyay, S and Samanta, I}, title = {Multi-drug resistant, biofilm-producing high-risk clonal lineage of Klebsiella in companion and household animals.}, journal = {Letters in applied microbiology}, volume = {71}, number = {6}, pages = {580-587}, doi = {10.1111/lam.13381}, pmid = {32881009}, issn = {1472-765X}, support = {1G-25/2016//Department of Science & Technology and Biotechnology, Government of West Bengal/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cats/microbiology ; Cefotaxime/pharmacology ; Dogs/microbiology ; *Drug Resistance, Multiple, Bacterial ; Goats/microbiology ; India ; Klebsiella/classification/*drug effects/enzymology/physiology ; Klebsiella Infections/drug therapy ; Livestock/*microbiology ; Pets/*microbiology ; Sheep ; beta-Lactamases/genetics/metabolism ; }, abstract = {Antimicrobial resistance is a global emergency which needs one health approach to address. The present study was conducted to detect the prevalence of beta-lactamase and biofilm-producing Klebsiella strains in rectal swabs (n = 624) collected from healthy dogs, cats, sheep and goats reared as companion or household animals in India. The dogs and cats were frequently exposed to third- or fourth-generation cephalosporins for therapy. The sheep and goats were occasionally exposed to antibiotics and had environmental exposure. Phenotypical ESBL (n = 93) and ACBL (n = 88)-producing Klebsiella were isolated significantly more (P < 0·05) from companion animals than household animals. Majority of the Klebsiella possessed blaCTX-M-15 . The sequences blaCTX-M-15.2 , blaCTX-M-197 and blaCTX-M-225 are reported first time from the companion animals. All ACBL-producing isolates possessed blaAmpC . The present study detected 65·8% of Klebsiella strains as biofilm producers possessing the studied biofilm associated genes. The isolates showed phenotypical resistance against chloramphenicol, tetracycline, doxycycline, co-trimoxazole, ampicillin, cefotaxime/clavulanic acid. The present study showed that companion and household animals (dogs, cats, sheep, goats) may act as a carrier of ESBL/biofilm-producing, multi-drug resistant, high-risk clonal lineage of Klebsiella.}, } @article {pmid32880989, year = {2021}, author = {Pereira, TC and Dijkstra, RJB and Petridis, X and Sharma, PK and van de Meer, WJ and van der Sluis, LWM and de Andrade, FB}, title = {Chemical and mechanical influence of root canal irrigation on biofilm removal from lateral morphological features of simulated root canals, dentine discs and dentinal tubules.}, journal = {International endodontic journal}, volume = {54}, number = {1}, pages = {112-129}, pmid = {32880989}, issn = {1365-2591}, support = {//European Society of Endodontology/ ; //Abel Tasman Talent Program/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 2010/20196-3//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Dentin ; *Root Canal Irrigants/pharmacology ; Root Canal Preparation ; Sodium Hypochlorite/pharmacology ; Therapeutic Irrigation ; }, abstract = {AIM: To investigate the anti-biofilm efficacy of irrigation using a simulated root canal model, the chemical effect of irrigants against biofilms grown on dentine discs and their impact on biofilm viscoelasticity, the efficacy of the irrigants in decontaminating infected dentinal tubules and the capacity of bacteria to regrow.

METHODOLOGY: Biofilm removal, viscoelastic analysis of remaining biofilms and bacterial viability were evaluated using a simulated root canal model with lateral morphological features, dentine discs and a dentinal tubule model, respectively. Experiments were conducted using a two-phase irrigation protocol. Phase 1: a modified salt solution (RISA) and sodium hypochlorite (NaOCl) were used at a low flow rate to evaluate the chemical action of the irrigants. Ultrasonic activation (US) of a chemically inert solution (buffer) was used to evaluate the mechanical efficacy of irrigation. Phase 2: a final irrigation with buffer at a high flow rate was performed for all groups. Optical coherence tomography (OCT), low load compression testing (LLCT) and confocal scanning laser microscopy analysis were used in the different models. One-way analysis of variance (anova) was performed for the OCT and LLCT analysis, whilst Kruskal-Wallis and Wilcoxon ranked tests for the dentinal tubule model.

RESULTS: US and high flow rate removed significantly more biofilm from the artificial lateral canal. For biofilm removal from the artificial isthmus, no significant differences were found between the groups. Within-group analysis revealed significant differences between the steps of the experiment, with the exception of NaOCl. For the dentine discs, no significant differences regarding biofilm removal and viscoelasticity were detected. In the dentinal tubule model, NaOCl exhibited the greatest anti-biofilm efficacy.

CONCLUSIONS: The mechanical effect of irrigation is important for biofilm removal. An extra high flow irrigation rate resulted in greater biofilm removal than US in the artificial isthmus. The mechanical effect of US seemed to be more effective when the surface contact biofilm-irrigant was small. After the irrigation procedures, the remaining biofilm could survive after a 5-day period. RISA and NaOCl seemed to alter post-treatment remaining biofilms.}, } @article {pmid32880907, year = {2021}, author = {Kim, HS and Cha, E and Ham, SY and Park, JH and Nam, S and Kwon, H and Byun, Y and Park, HD}, title = {Linoleic acid inhibits Pseudomonas aeruginosa biofilm formation by activating diffusible signal factor-mediated quorum sensing.}, journal = {Biotechnology and bioengineering}, volume = {118}, number = {1}, pages = {82-93}, doi = {10.1002/bit.27552}, pmid = {32880907}, issn = {1097-0290}, support = {1485016734//Korea Ministry of Environment/ ; }, mesh = {Biofilms/*drug effects/growth & development ; Fatty Acids, Monounsaturated/*metabolism ; Linoleic Acid/*pharmacology ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing/*drug effects ; Signal Transduction/*drug effects ; }, abstract = {Bacterial biofilm formation causes serious problems in various fields of medical, clinical, and industrial settings. Antibiotics and biocide treatments are typical methods used to remove bacterial biofilms, but biofilms are difficult to remove effectively from surfaces due to their increased resistance. An alternative approach to treatment with antimicrobial agents is using biofilm inhibitors that regulate biofilm development without inhibiting bacterial growth. In the present study, we found that linoleic acid (LA), a plant unsaturated fatty acid, inhibits biofilm formation under static and continuous conditions without inhibiting the growth of Pseudomonas aeruginosa. LA also influenced the bacterial motility, extracellular polymeric substance production, and biofilm dispersion by decreasing the intracellular cyclic diguanylate concentration through increased phosphodiesterase activity. Furthermore, quantitative gene expression analysis demonstrated that LA induced the expression of genes associated with diffusible signaling factor-mediated quorum sensing that can inhibit or induce the dispersion of P. aeruginosa biofilms. These results suggest that LA is functionally and structurally similar to a P. aeruginosa diffusible signaling factor (cis-2-decenoic acid) and, in turn, act as an agonist molecule in biofilm dispersion.}, } @article {pmid32880470, year = {2021}, author = {Pu, H and Xu, Y and Sun, DW and Wei, Q and Li, X}, title = {Optical nanosensors for biofilm detection in the food industry: principles, applications and challenges.}, journal = {Critical reviews in food science and nutrition}, volume = {61}, number = {13}, pages = {2107-2124}, doi = {10.1080/10408398.2020.1808877}, pmid = {32880470}, issn = {1549-7852}, mesh = {Bacteria ; *Biofilms ; Food Handling ; Food Industry ; *Food-Processing Industry ; Humans ; }, abstract = {Biofilms are the universal lifestyle of bacteria enclosed in extracellular polymeric substances (EPS) on the contact surfaces of food processing facilities. The EPS-encapsulated foodborne bacterial pathogens are the main food contaminant sources, posing a serious threat to human health. The microcrystalline, sophisticated and dynamic biofilms necessitate the development of conventional microscopic imaging and spectral technology. Nanosensors, which can transfer the biochemical information into optical signals, have recently emerged for biofilm optical detection with high sensitivity and high spatial resolution at nanoscale scopes. Therefore, the aim of this review is to clarify the main detection scope in biofilms and the detection principles of optical nanosensors arousing Raman enhancement, fluoresce conversion and color change. The difficulties and challenges of biofilm characterization including the secretion and variation of main biochemical components are first discussed, the details about the principles and application examples of bioassays targeting foodborne pathogens based on optical nanosensors are then summarized. Finally, the challenges and future trends in developing optical nanosensors are also highlighted. The current review indicates that optical nanosensors have taken the challenges of detecting biofilm in complex food samples, including the characterization of biofilm formation mechanism, identification of microbial metabolic activities, diagnosis of potential food pathogens and sanitation monitoring of food processing equipment. Numerous in-depth explorations and various trials have proven that the bioassays based on multifunctional optical nanosensors are promising to ensure and promote food safety and quality. However, there still remains a daunting challenge to structure reproducible, biocompatible and applicable nano-sensors for biofilm characterization, identification, and imaging.}, } @article {pmid32879370, year = {2020}, author = {Kim, HJ and Cho, MY and Lee, ES and Jung, HI and Kim, BI}, title = {Effects of short-time exposure of surface pre-reacted glass-ionomer eluate on dental microcosm biofilm.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {14425}, pmid = {32879370}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Glass Ionomer Cements/*pharmacology ; Humans ; Microbiota/drug effects ; Mouth/microbiology ; }, abstract = {This study evaluated the antibacterial effects of short-time exposure of surface pre-reacted glass-ionomer (S-PRG) eluate on oral microcosm biofilm. Biofilms were treated with an S-PRG eluate at different concentrations (25%, 50%, and 100%), distilled water (DW), and 0.1% chlorhexidine (CHX) twice a day for 5 min repeatedly. After 7 days, the total and aciduric bacterial counts and biofilm dry weights were measured. An image analysis program calculated the red/green (R/G) ratios in the biofilm autofluorescence images. Microscopic analyses quantified the biofilm thickness and live/dead cell ratio and determined morphological changes in the biofilm. Bacterial counts and dry weights were not significantly different in the DW group for all S-PRG eluate concentrations. An increasing trend in the R/G ratio for 7 days biofilm treatment was observed for the S-PRG eluate and the DW groups. Furthermore, the live/dead cell ratios in the biofilm and the biofilm thickness of the S-PRG eluate groups were similar to those of the DW group. The bacteria morphology inside the biofilm changed only in the CHX group. Short-time S-PRG eluate treatment showed no significant antibacterial and antibiofilm effects. These results indicated that limited biofilm formation inhibition can be obtained by using only the S-PRG eluate.}, } @article {pmid32879157, year = {2020}, author = {Galván-Pacheco, J and Vitales-Noyola, M and González-Amaro, AM and Bujanda-Wong, H and Aragón-Piña, A and Méndez-González, V and Pozos-Guillén, A}, title = {Evaluation of in vitro biofilm elimination of Enterococcus faecalis using a continuous ultrasonic irrigation device.}, journal = {Journal of oral science}, volume = {62}, number = {4}, pages = {415-419}, doi = {10.2334/josnusd.19-0399}, pmid = {32879157}, issn = {1880-4926}, mesh = {Biofilms ; Dental Pulp Cavity ; *Enterococcus faecalis ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Therapeutic Irrigation ; Ultrasonics ; }, abstract = {This study sought to evaluate biofilm elimination using the HBW Ultrasonic Ring based on continuous ultrasonic irrigation. Forty-five premolars and molars with complex curvatures were included. An Enterococcus faecalis biofilm was established for 30 days on the extracted teeth. The teeth were then stratified into three experimental groups for instrumentation and irrigation (i.e. HBW Ultrasonic Ring, conventional irrigation, and passive ultrasonic irrigation). Pre- and post-instrumentation samples were collected, and reductions of bacterial load were evaluated by McFarland's scale, counting of colony-forming units, and scanning electronic microscopy. The HBW Ultrasonic Ring promoted a higher reduction in bacterial load relative to conventional irrigation (P < 0.05) and a similar reduction compared with passive ultrasonic irrigation (P > 0.05). These results suggest the HBW Ultrasonic Ring is a promising alternative modality for simultaneous instrumentation and irrigation during root canal treatment, achieving an appropriate level of bacterial reduction and allowing the passage of the irrigating solution throughout the entire working length.}, } @article {pmid32878628, year = {2020}, author = {Hunt, CM and Collins, CM and Benedict, MQ}, title = {Measuring and reducing biofilm in mosquito rearing containers.}, journal = {Parasites & vectors}, volume = {13}, number = {1}, pages = {439}, pmid = {32878628}, issn = {1756-3305}, support = {OPP1141988//Bill and Melinda Gates Foundation/ ; }, mesh = {Animals ; Aquaculture ; Bacteria/drug effects ; Biofilms/*drug effects ; Culicidae/*growth & development ; Equipment and Supplies/microbiology ; Larva/growth & development ; Sodium Hypochlorite/pharmacology ; }, abstract = {BACKGROUND: Mosquito rearing containers contain organic-rich water that nourishes numerous bacteria, some of which are capable of forming biofilms. Biofilm is broadly an extracellular polymeric matrix (EPS) in which living bacteria occur, and the accumulation of biofilm is possible during routine stock-keeping as most of these containers are re-used. Whether biofilm has an effect on the mosquito rearing is not a question that has been investigated, nor have measures to reduce biofilm in this context been systematically studied.

METHODS: We measured biofilm accumulation in standard rearing containers by staining with crystal violet and determining the OD using a spectrophotometer. We also treated rearing containers with 0.1% sodium hypochlorite to determine its effectiveness in reducing biofilm abundance. Lastly, we performed an analysis of the relationship between the occurrence of biofilm and the likelihood of microbial blooms that were associated with larval death during trials of larval diets.

RESULTS: We observed that soaking rearing containers overnight in 0.1% sodium hypochlorite greatly reduced biofilm, but we observed no relationship between the use of containers that had not been treated with bleach and subsequent microbial blooms.

CONCLUSIONS: Larva rearing leaves detectable biofilm. While we were unable to correlate microbial blooms with the presence of biofilm, as a precaution, we recommend that plastic containers that are re-used be treated with 0.1% sodium hypochlorite occasionally.}, } @article {pmid32877731, year = {2020}, author = {Guo, P and Xue, HY and Buttaro, BA and Tran, NT and Wong, HL}, title = {Enhanced eradication of intracellular and biofilm-residing methicillin-resistant Staphylococcus aureus (MRSA) reservoirs with hybrid nanoparticles delivering rifampicin.}, journal = {International journal of pharmaceutics}, volume = {589}, number = {}, pages = {119784}, pmid = {32877731}, issn = {1873-3476}, support = {R01 AI132852/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; *Nanoparticles ; Rifampin ; *Staphylococcal Infections/drug therapy ; }, abstract = {Osteomyelitis carries a high risk of recurrence even after extended, aggressive antibiotic therapy. One of the key challenges is to eradicate the reservoirs of methicillin-resistant Staphylococcus aureus (MRSA) inside the host bone cells and their biofilms. Our goal is to develop rifampicin loaded lipid-polymer hybrid nanocarriers (Rf-LPN) and evaluate if they can achieve enhanced rifampicin delivery to eradicate these intracellular and biofilm-residing MRSA. After optimization of the composition, Rf-LPN demonstrated size around 110 nm in diameter that remained stable in serum-supplemented medium, drug payload up to 11.7% and sustained rifampicin release for 2 weeks. When comparing Rf-LPN with free rifampicin, moderate but significant (p < 0.05) improvement of the activities against three osteomyelitis-causing bacteria (USA300-0114, CDC-587, RP-62A) in planktonic form were observed. In comparison, the enhancements in the activities against the biofilms and intracellular MRSA by Rf-LPN were even more substantial. The MBEC50 values against USA300-0114, CDC-587, and RP-62A were 42 vs 155, 70 vs 388, and 265 ng/ml vs over 400 ng/ml, respectively, and up to 18.5-fold reduction in the intracellular MRSA counts in osteoblasts was obtained. Confocal microscope images confirmed extensive accumulation of Rf-LPN inside the biofilm matrix and MRSA-infected osteoblasts. Overall, in this proof-of-concept study we have developed and validated the strategy to exploit the nanoparticle-cell and nanoparticle-biofilm interactions with a new rifampicin nanoformulation for prevention of osteomyelitis recurrence and chronicity caused by the elusive MRSA.}, } @article {pmid32876953, year = {2020}, author = {Manna, S and Ghanty, C and Baindara, P and Barik, TK and Mandal, SM}, title = {Electrochemical communication in biofilm of bacterial community.}, journal = {Journal of basic microbiology}, volume = {60}, number = {10}, pages = {819-827}, doi = {10.1002/jobm.202000340}, pmid = {32876953}, issn = {1521-4028}, mesh = {Bacteria/metabolism ; *Bacterial Physiological Phenomena ; *Biofilms/growth & development ; Cell Membrane/metabolism ; Drug Resistance, Bacterial ; Electrophysiological Phenomena ; Ion Channels/metabolism ; Membrane Potentials ; Microbial Interactions ; Signal Transduction ; }, abstract = {Electrochemical communication during biofilm formation has recently been identified. Bacteria within biofilm-adopt different strategies for electrochemical communication such as direct contact via membrane-bound molecules, diffusive electron transfer via soluble redox-active molecules, and ion channel-mediated long-range electrochemical signaling. Long-range electrical signals are important to communicate with distant members within the biofilm, which function through spatially propagating waves of potassium ion (K[+]) that depolarizes neighboring cells. During propagation, these waves coordinate between the metabolic states of interior and peripheral cells of the biofilm. The understanding of electrochemical communication within the biofilm may provide new strategies to control biofilm-mediated drug resistance. Here, we summarized the different mechanisms of electrochemical communication among bacterial populations and suggested its possible role in the development of high level of antibiotic resistance. Thus, electrochemical signaling opens a new avenue concerning the electrophysiology of bacterial biofilm and may help to control the biofilm-mediated infection by developing future antimicrobials.}, } @article {pmid32874465, year = {2020}, author = {Astuti, SD and Hafidiana, and Rulaningtyas, R and Abdurachman, and Putra, AP and Samian, and Arifianto, D}, title = {The efficacy of photodynamic inactivation with laser diode on Staphylococcus aureus biofilm with various ages of biofilm.}, journal = {Infectious disease reports}, volume = {12}, number = {Suppl 1}, pages = {8736}, pmid = {32874465}, issn = {2036-7430}, abstract = {Biofilms are able to cause microorganisms to be 80% more resistant to antibiotics. The extracelullar polymeric substance (EPS) in biofilm functions to protect bacteria, making it difficult for antibiotics to penetrate the biofilm layer. This study aims to determine the effectiveness of photodynamic inactivation with blue diode laser to reduce Staphylococcus aureus biofilm at various ages of biofilms. The light source is a 403 nm blue diode laser with an energy power of about 27.65±0.01 mW. The study was designed with two groups: Group C was the untreated control group with variations in age of biofilms (0; 6; 11; 17; 24; 32; 40 and 48) hours; Group T was a laser treatment group with variations in age of biofilm and energy density (4.23; 8.46; 12.70; 16.93 and 21.16) J/cm[2]. Biofilm reduction measurement method using ELISA test was performed to calculate OD[595] value. The statistical analysis results of variance showed that there was an influence of biofilm age and irradiation energy density of laser on biofilm reduction. Optical density analysis showed the most optimum biofilm reduction happened when biofilm age is perfectly constructed (about 17 hours) and with 91% reduction. The longer biofilm age lived among those biofilms, the greater the reduction. The results of the Scanning Microscope Electron and fluorescent microscope measurement showed destruction site of the EPS biofilm and bacterial cell death. So, the activated photodynamic with 403 nm laser diode is effective to reduce the Staphylococcus aureus biofilm in the maturation phase.}, } @article {pmid32874454, year = {2020}, author = {Kriswandini, IL and I, D and Tantiana, and P, N and T, B and Ia, P and Pnbn, T}, title = {The forming of bacteria biofilm from Streptococcus mutans and Aggregatibacter actinomycetemcomitans as a marker for early detection in dental caries and periodontitis.}, journal = {Infectious disease reports}, volume = {12}, number = {Suppl 1}, pages = {8722}, pmid = {32874454}, issn = {2036-7430}, abstract = {BACKGROUND: This is an initial study of the biofilm of Streptococcus mutans (S.mutans) and Aggregatibacter actinomycetemcomitans (A.a). S. mutans and A.aare bacteria that cause infection diseases in the oral cavity. These bacteria have the ability to form biofilms. The study of bacterial biofilm proteins was used as an alternative to early prevention for oral infections. It would be used for the purpose of creating a marker for Infection Detection Kit in the oral cavity.

OBJECTIVE: To easily detect caries or Periodontitis with the biofilms of S. mutans and A.a at the early stage. The forming of biofilm proteins from S.mutans and A.a induced with 5% glucose, 5% lactose, 5% soy protein, and 5% iron will be use as a marker for early detection to Dental caries and Periodontitis.

METHODS: SDS-PAGE electrophoresis technique was used in the study to measure the molecular weight of S. mutans and A.a biofilms induced with 5% glucose, 5% lactose, 5% soy protein, and 5% iron.

RESULTS: Biofilm bands of S. mutans and A.a were formed with the various numbers depending on the induction used. These results are early chararterization of biofilm that will beused as a marker for early detection of infectious diseases in oral cavity (Dental Caries and Periodontitis).

CONCLUSIONS S MUTANS: bacteria induced with 5% glucose had one band of biofilm protein, with 5% lactose had four bands of biofilm proteins, and with soy protein had seven bands of biofilm protein, but with 5% iron did not produce any protein bands and neither did A.a.}, } @article {pmid32873610, year = {2020}, author = {She, Q and Hunter, E and Qin, Y and Nicolau, S and Zalis, EA and Wang, H and Chen, Y and Chai, Y}, title = {Negative Interplay between Biofilm Formation and Competence in the Environmental Strains of Bacillus subtilis.}, journal = {mSystems}, volume = {5}, number = {5}, pages = {}, pmid = {32873610}, issn = {2379-5077}, abstract = {Environmental strains of the soil bacterium Bacillus subtilis have valuable applications in agriculture, industry, and biotechnology; however, environmental strains are genetically less accessible. This reduced accessibility is in sharp contrast to laboratory strains, which are well known for their natural competence, and a limitation in their applications. In this study, we observed that robust biofilm formation by environmental strains of B. subtilis greatly reduced the frequency of competent cells in the biofilm. By using model strain 3610, we revealed a cross-pathway regulation that allows biofilm matrix producers and competence-developing cells to undergo mutually exclusive cell differentiation. We further demonstrated that the competence activator ComK represses the key biofilm regulatory gene sinI by directly binding to the sinI promoter, thus blocking competent cells from simultaneously becoming matrix producers. In parallel, the biofilm activator SlrR represses competence through three distinct mechanisms involving both genetic regulation and cell morphological changes. Finally, we discuss the potential implications of limiting competence in a bacterial biofilm.IMPORTANCE The soil bacterium Bacillus subtilis can form robust biofilms, which are important for its survival in the environment. B. subtilis also exhibits natural competence. By investigating competence development in B. subtilis in situ during biofilm formation, we reveal that robust biofilm formation often greatly reduces the frequency of competent cells within the biofilm. We then characterize a cross-pathway regulation that allows cells in these two developmental events to undergo mutually exclusive cell differentiation during biofilm formation. Finally, we discuss potential biological implications of limiting competence in a bacterial biofilm.}, } @article {pmid32873073, year = {2020}, author = {Xu, J and Gao, Y and Meng, Y and Wu, W and Tsauo, C and Guo, T and Cao, Y and Huang, D and Zhou, X and He, J}, title = {Mechano-chemical coupling of irrigation enhances endodontic biofilm debridement.}, journal = {Biofouling}, volume = {36}, number = {7}, pages = {792-799}, doi = {10.1080/08927014.2020.1814753}, pmid = {32873073}, issn = {1029-2454}, mesh = {*Biofilms ; Debridement ; Enterococcus faecalis ; *Root Canal Irrigants ; *Sodium Hypochlorite ; }, abstract = {The complexity of the root canal system results in areas where mechanical instrumentation is impossible during endodontic treatment. To disinfect these areas, the effect of irrigation on biofilm debridement is of great significance but has not yet been well explored. Using an in vitro Enterococcus faecalis biofilm model and a biofilm reactor, the present study provides a better understanding of the relative contributions of mechanical and chemical effects of irrigation on biofilm removal, as well as the factors influencing their coupling efficiency. The results clearly demonstrate that, the mechanical effect of irrigation alone does not significantly influence the stability of biofilms. However, the mechanical effect promotes biofilm eradication by coupling with the chemical effect. In addition, both the irrigant concentration and the irrigant-biofilm contact time are among the key factors affecting the mechano-chemical coupling. This knowledge may serve to better direct endodontists in designing irrigation regimes during root canal therapy.}, } @article {pmid32872324, year = {2020}, author = {Wang, G and Zhao, G and Chao, X and Xie, L and Wang, H}, title = {The Characteristic of Virulence, Biofilm and Antibiotic Resistance of Klebsiella pneumoniae.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {17}, pages = {}, pmid = {32872324}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Drug Resistance, Microbial ; Genes, Bacterial ; Humans ; Klebsiella Infections/*drug therapy/epidemiology/*microbiology ; Klebsiella pneumoniae/*drug effects/genetics/isolation & purification/pathogenicity ; Polymerase Chain Reaction ; Virulence/genetics ; Virulence Factors ; }, abstract = {Klebsiella pneumoniae is an important gram-negative opportunistic pathogen that causes a variety of infectious diseases, including urinary tract infections, bacteremia, pneumonia, and liver abscesses. With the emergence of multidrug-resistant (MDR) and hypervirulent K. pneumoniae (hvKP) strains, the rapid spread of these clinical strains in geography is particularly worrying. However, the detailed mechanisms of virulence and antibiotic resistance in K. pneumoniae are still not very clear. Therefore, studying and elucidating the pathogenic mechanisms and drug resistance mechanism of K. pneumoniae infection are important parts of current medical research. In this paper, we systematically summarized the virulence, biofilm, and antibiotic tolerance mechanisms of K. pneumoniae, and explored the application of whole genome sequencing and global proteomics, which will provide new clues for clinical treatment of K. pneumoniae.}, } @article {pmid32872142, year = {2020}, author = {Hall, DC and Król, JE and Cahill, JP and Ji, HF and Ehrlich, GD}, title = {The Development of a Pipeline for the Identification and Validation of Small-Molecule RelA Inhibitors for Use as Anti-Biofilm Drugs.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32872142}, issn = {2076-2607}, support = {R01 DC002148/DC/NIDCD NIH HHS/United States ; 02148/DC/NIDCD NIH HHS/United States ; }, abstract = {Biofilm infections have no approved effective medical treatments and can only be disrupted via physical means. This means that any biofilm infection that is not addressable surgically can never be eliminated and can only be managed as a chronic disease. Therefore, there is an urgent need for the development of new classes of drugs that can target the metabolic mechanisms within biofilms which render them recalcitrant to traditional antibiotics. Persister cells within the biofilm structure may play a large role in the enhanced antibiotic recalcitrance of bacteria biofilms. Biofilm persister cells can be resistant to up to 1000 times the minimal inhibitory concentrations of many antibiotics, as compared to their planktonic envirovars; they are thought to be the prokaryotic equivalent of metazoan stem cells. Their metabolic resistance has been demonstrated to be an active process induced by the stringent response that is triggered by the ribosomally-associated enzyme RelA in response to amino acid starvation. This 84-kD pyrophosphokinase produces the "magic spot" alarmones, collectively called (p)ppGpp. These alarmones act by directly regulating transcription by binding to RNA polymerase. These transcriptional changes lead to a major shift in cellular function to both upregulate oxidative stress-combating enzymes and down regulate major cellular functions associated with growth and replication. These changes in gene expression produce the quiescent persister cells. In this work, we describe a hybrid in silico laboratory pipeline for identifying and validating small-molecule inhibitors of RelA for use in the combinatorial treatment of bacterial biofilms as re-potentiators of classical antibiotics.}, } @article {pmid32871619, year = {2020}, author = {Zeller, B and Stöckli, S and Zaugg, LK and Astasov-Frauenhoffer, M and Hauser-Gerspach, I and Waltimo, T and Zitzmann, NU}, title = {Biofilm formation on metal alloys, zirconia and polyetherketoneketone as implant materials in vivo.}, journal = {Clinical oral implants research}, volume = {31}, number = {11}, pages = {1078-1086}, doi = {10.1111/clr.13654}, pmid = {32871619}, issn = {1600-0501}, mesh = {Alloys ; Benzophenones ; Biofilms ; *Dental Implants ; Humans ; Polymers ; Surface Properties ; Titanium ; *Zirconium ; }, abstract = {OBJECTIVES: This study investigated biofilm formation on discs of metal alloys, zirconia and polyetherketoneketone in vivo.

MATERIAL AND METHODS: Sixteen healthy volunteers conducted two runs of 24 hr each wearing an intraoral splint with 15 discs representing five different materials (gold-based [EL] and silver-based [PA] noble metal alloys; zirconia [ZR]; polyetherketoneketone [PEKK]; titanium zirconium alloy [TiZr]). Safranin staining assays and colony-forming unit (CFU) counts were conducted. Linear mixed-effects models were used to compare materials, and geometric mean ratios with 95% confidence interval were calculated with the level of significance set at α = 0.05.

RESULTS: Less biofilm mass and lower CFU counts were found on PA and EL, while ZR and PEKK developed similar levels as the reference material TiZr alloy. Compared with PA, biofilm mass was 1.5 times higher for EL (p = .004), 1.7 times higher for PEKK (p < .001), 2.2 times higher for TiZr (p < .001) and 2.4 times higher for ZR (p < .001). The culturing method confirmed these results for EL and PA with lower CFU compared to TiZr. The biomass staining technique and cell culturing correlated for EL and PA.

CONCLUSION: Silver-based noble alloy and gold-based high noble alloy demonstrated the least biofilm formation indicating a potential clinical use as material for implant components in the transmucosal compartment. Zirconia and Polyetherketoneketone revealed similar results as the reference material titanium zirconium alloy used in commercially available titanium dental implant.}, } @article {pmid32871610, year = {2020}, author = {Herrmann, H and Kern, JS and Kern, T and Lautensack, J and Conrads, G and Wolfart, S}, title = {Early and mature biofilm on four different dental implant materials: An in vivo human study.}, journal = {Clinical oral implants research}, volume = {31}, number = {11}, pages = {1094-1104}, doi = {10.1111/clr.13656}, pmid = {32871610}, issn = {1600-0501}, support = {CF41001//Oral Reconstruction Foundation (previously Camlog Foundation)/ ; }, mesh = {Bacterial Adhesion ; Biofilms ; *Dental Implants ; Dental Materials ; Humans ; Surface Properties ; Titanium ; Zirconium ; }, abstract = {OBJECTIVES: The aim of this study was to examine the microbial composition of early (after 3 days, D3) and mature biofilms (after 31 days, D31) on materials typically used in implant/abutment buildups. Implant/abutment materials with different surface roughness values (Ra) were compared to detect differences in the quantity and quality of bacterial composition.

MATERIAL AND METHODS: Four different materials were investigated: rough implant surface (sand-blasted acid-etched titanium, Ti-p), implant collar (machined titanium, Ti-m), titanium abutment (Ti6Al4V), and zirconium dioxide abutment (ZrO2). Fourteen periodontally healthy subjects received mandibular acrylic devices with four disks (one for each material) facing the anterior lingual area. The total bacterial count was analyzed using RT-qPCR. Both presence and proliferation of 20 selected bacterial species were assessed with microarrays.

RESULTS: The highest mean total cell counts (x10[8]  ± standard deviation) were detected at D3 on ZrO2 (5.63 ± 4.83; Ra  = 0.74 µm), followed by Ti-p (4.53 ± 5.00; Ra  = 1.87), Ti-m (4.43 ± 9.38; Ra  = 0.18 µm), and Ti6Al4V (3.83 ± 3.13; Ra  = 0.16 µm). ZrO2 showed significantly higher total bacterial cell counts than Ti-p and Ti-m (p < .05) for both time intervals. The microarrays detected 16 (D3) and 17 (D31) bacterial species; those associated with healthy oral microbiotas, but also bacteria of the red complex (Tannerella forsythia, Treponema denticola), were found on all materials.

CONCLUSIONS: Biofilms on ZrO2 harbored a higher total number of bacterial cells compared with those formed on titanium surfaces with much lower roughness values. Putative periodontopathogens were detected on all materials after both time intervals. Implant/abutment materials with a low surface roughness showed less biofilm accumulation.}, } @article {pmid32871516, year = {2020}, author = {Mahto, KU and Das, S}, title = {Whole genome characterization and phenanthrene catabolic pathway of a biofilm forming marine bacterium Pseudomonas aeruginosa PFL-P1.}, journal = {Ecotoxicology and environmental safety}, volume = {206}, number = {}, pages = {111087}, doi = {10.1016/j.ecoenv.2020.111087}, pmid = {32871516}, issn = {1090-2414}, mesh = {Bacterial Proteins/genetics ; Biodegradation, Environmental ; Biofilms/*growth & development ; Genome, Bacterial/*genetics ; Marine Biology ; Metabolic Networks and Pathways/*genetics ; Phenanthrenes/*metabolism ; Plasmids/genetics ; Polycyclic Aromatic Hydrocarbons/metabolism ; Pseudomonas aeruginosa/genetics/growth & development/metabolism/*physiology ; }, abstract = {Pseudomonas aeruginosa is a small rod shaped Gram-negative bacterium of Gammaproteobacteria class known for its metabolic versatility. P. aeruginosa PFL-P1 was isolated from Polycyclic Aromatic Hydrocarbons (PAHs) contaminated site of Paradip Port, Odisha Coast, India. The strain showed excellent biofilm formation and could retain its ability to form biofilm grown with different PAHs in monoculture as well as co-cultures. To explore mechanistic insights of PAHs metabolism, the whole genome of the strain was sequenced. Next generation sequencing unfolded a genome size of 6,333,060 bp encoding 5857 CDSs. Gene ontology distribution assigned to a total of 2862 genes, wherein 2235 genes were allocated to biological process, 1549 genes to cellular component and 2339 genes to molecular function. A total of 318 horizontally transferred genes were identified when the genome was compared with the reference genomes of P. aeruginosa PAO1 and P. aeruginosa DSM 50071. Further comparison of P. aeruginosa PFL-P1 genome with P. putida containing TOL plasmids revealed similarities in the meta cleavage pathway employed for degradation of aromatic compounds like xylene and toluene. Gene annotation and pathway analysis unveiled 145 genes involved in xenobiotic biodegradation and metabolism. The biofilm cultures of P. aeruginosa PFL-P1 could degrade ~74% phenanthrene within 120 h while degradation increased up to ~76% in co-culture condition. GC-MS analysis indicated presence of diverse metabolites indicating the involvement of multiple pathways for one of the PAHs (phenanthrene) degradation. The strain also possesses the genetic machinery to utilize diverse toxic aromatic compounds such as naphthalene, benzoate, aminobenzoate, fluorobenzoate, toluene, xylene, styrene, atrazine, caprolactam etc. Common catabolic gene clusters such as benABCD, xylXYZ and catAB were observed within the genome of P. aeruginosa PFL-P1 which play key roles in the degradation of various toxic aromatic compounds.}, } @article {pmid32871431, year = {2020}, author = {Gui, Y and Bai, X and Zhong, X and Sikder, MNA and Xu, H}, title = {Seasonal variability in biological trait pattern of biofilm-dwelling protozoa in colonization surveys for marine bioassessment.}, journal = {Marine pollution bulletin}, volume = {160}, number = {}, pages = {111604}, doi = {10.1016/j.marpolbul.2020.111604}, pmid = {32871431}, issn = {1879-3363}, mesh = {Biofilms ; China ; *Ciliophora ; Environmental Monitoring ; Seasons ; Surveys and Questionnaires ; }, abstract = {Biological trait analysis (BTA) has been proved to be a powerful tool to evaluate marine water quality. The species trait distributions of biofilm-dwelling protozoa were studied in a coastal region of the Yellow Sea, northern China, during a four-season cycle. The BTA demonstrated that: (1) the protozoa showed a significant seasonal variability in biological trait pattern during the colonization process across four seasons; (2) the colonization dynamics in species trait distribution followed different temporal models; (3) the functional dynamics in spring and summer were significantly different from those in autumn and winter (P < 0.05); and (4) functional diversity showed lower values in spring and summer than in autumn and winter. These findings suggest that BTA is subject to a high seasonal variability during colonization surveys when protozoa are used as bioindicators of marine water quality.}, } @article {pmid32869465, year = {2020}, author = {Pruteanu, M and Hernández Lobato, JI and Stach, T and Hengge, R}, title = {Common plant flavonoids prevent the assembly of amyloid curli fibres and can interfere with bacterial biofilm formation.}, journal = {Environmental microbiology}, volume = {22}, number = {12}, pages = {5280-5299}, doi = {10.1111/1462-2920.15216}, pmid = {32869465}, issn = {1462-2920}, support = {//Berliner Sparkassenstiftung Medizin/ ; }, mesh = {Amyloid/*metabolism ; Anti-Bacterial Agents/*pharmacology ; Bacteria/classification/*drug effects/growth & development ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Extracellular Polymeric Substance Matrix/drug effects/metabolism ; Flavonoids/*pharmacology ; Humans ; Protein Multimerization/drug effects ; Species Specificity ; }, abstract = {Like all macroorganisms, plants have to control bacterial biofilm formation on their surfaces. On the other hand, biofilms are highly tolerant against antimicrobial agents and other stresses. Consequently, biofilms are also involved in human chronic infectious diseases, which generates a strong demand for anti-biofilm agents. Therefore, we systematically explored major plant flavonoids as putative anti-biofilm agents using different types of biofilms produced by Gram-negative and Gram-positive bacteria. In Escherichia coli macrocolony biofilms, the flavone luteolin and the flavonols myricetin, morin and quercetin were found to strongly reduce the extracellular matrix. These agents directly inhibit the assembly of amyloid curli fibres by driving CsgA subunits into an off-pathway leading to SDS-insoluble oligomers. In addition, they can interfere with cellulose production by still unknown mechanisms. Submerged biofilm formation, however, is hardly affected. Moreover, the same flavonoids tend to stimulate macrocolony and submerged biofilm formation by Pseudomonas aeruginosa. For Bacillus subtilis, the flavonone naringenin and the chalcone phloretin were found to inhibit growth. Thus, plant flavonoids are not general anti-biofilm compounds but show species-specific effects. However, based on their strong and direct anti-amyloidogenic activities, distinct plant flavonoids may provide an attractive strategy to specifically combat amyloid-based biofilms of some relevant pathogens.}, } @article {pmid32867504, year = {2020}, author = {Gardin, E and Zanna, S and Seyeux, A and Mercier, D and Allion-Maurer, A and Marcus, P}, title = {Early stage of marine biofilm formation on duplex stainless steel.}, journal = {Biointerphases}, volume = {15}, number = {4}, pages = {041014}, doi = {10.1116/6.0000361}, pmid = {32867504}, issn = {1559-4106}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Pseudoalteromonas/*physiology ; Seawater/microbiology ; Spectrometry, Mass, Secondary Ion ; Stainless Steel/*chemistry/pharmacology ; Surface Properties ; }, abstract = {The aim of this work was to investigate the bacteria-surface interactions occurring during the first hour of adhesion of marine Pseudoalteromonas NCIMB 2021 at the surface of 2304 lean duplex stainless steel in artificial seawater. A complete characterization of the biofilm and the passive film was performed coupling epifluorescence microscopy, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time of flight secondary ion mass spectrometry (ToF-SIMS). The coupling of XPS and ToF-SIMS analyses revealed that (1) protein and polysaccharide contents in the biofilm are similar in the presence or absence of nutrients, (2) the biofilm is mainly composed of proteins and the protein content is similar to the one of Tightly Bound EPS, (3) increased bacterial activity due to nutrients leads to chromium enrichment in the passive film in close vicinity to the bacteria.}, } @article {pmid32867208, year = {2020}, author = {Lamret, F and Colin, M and Mongaret, C and Gangloff, SC and Reffuveille, F}, title = {Antibiotic Tolerance of Staphylococcus aureus Biofilm in Periprosthetic Joint Infections and Antibiofilm Strategies.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32867208}, issn = {2079-6382}, abstract = {The need for bone and joint prostheses is currently growing due to population aging, leading to an increase in prosthetic joint infection cases. Biofilms represent an adaptive and quite common bacterial response to several stress factors which confer an important protection to bacteria. Biofilm formation starts with bacterial adhesion on a surface, such as an orthopedic prosthesis, further reinforced by matrix synthesis. The biofilm formation and structure depend on the immediate environment of the bacteria. In the case of infection, the periprosthetic joint environment represents a particular interface between bacteria, host cells, and the implant, favoring biofilm initiation and maturation. Treating such an infection represents a huge challenge because of the biofilm-specific high tolerance to antibiotics and its ability to evade the immune system. It is crucial to understand these mechanisms in order to find new and adapted strategies to prevent and eradicate implant-associated infections. Therefore, adapted models mimicking the infectious site are of utmost importance to recreate a relevant environment in order to test potential antibiofilm molecules. In periprosthetic joint infections, Staphylococcus aureus is mainly involved because of its high adaptation to the human physiology. The current review deals with the mechanisms involved in the antibiotic resistance and tolerance of Staphylococcus aureus in the particular periprosthetic joint infection context, and exposes different strategies to manage these infections.}, } @article {pmid32866726, year = {2020}, author = {Singh, T and Hook, AL and Luckett, J and Maitz, MF and Sperling, C and Werner, C and Davies, MC and Irvine, DJ and Williams, P and Alexander, MR}, title = {Discovery of hemocompatible bacterial biofilm-resistant copolymers.}, journal = {Biomaterials}, volume = {260}, number = {}, pages = {120312}, pmid = {32866726}, issn = {1878-5905}, support = {103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; MC_G0802525/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Animals ; *Anti-Bacterial Agents ; Biofilms ; Mice ; Pseudomonas aeruginosa ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Blood-contacting medical devices play an important role within healthcare and are required to be biocompatible, hemocompatible and resistant to microbial colonization. Here we describe a high throughput screen for copolymers with these specific properties. A series of weakly amphiphilic monomers are combinatorially polymerized with acrylate glycol monomers of varying chain lengths to create a library of 645 multi-functional candidate materials containing multiple chemical moieties that impart anti-biofilm, hemo- and immuno-compatible properties. These materials are screened in over 15,000 individual biological assays, targeting two bacterial species, one Gram negative (Pseudomonas aeruginosa) and one Gram positive (Staphylococcus aureus) commonly associated with central venous catheter infections, using 5 different measures of hemocompatibility and 6 measures of immunocompatibililty. Selected copolymers reduce platelet activation, platelet loss and leukocyte activation compared with the standard comparator PTFE as well as reducing bacterial biofilm formation in vitro by more than 82% compared with silicone. Poly(isobornyl acrylate-co-triethylene glycol methacrylate) (75:25) is identified as the optimal material across all these measures reducing P. aeruginosa biofilm formation by up to 86% in vivo in a murine foreign body infection model compared with uncoated silicone.}, } @article {pmid32866008, year = {2020}, author = {Liu, J and Hou, JS and Li, YB and Miao, ZY and Sun, PH and Lin, J and Chen, WM}, title = {Novel 2-Substituted 3-Hydroxy-1,6-dimethylpyridin-4(1H)-ones as Dual-Acting Biofilm Inhibitors of Pseudomonas aeruginosa.}, journal = {Journal of medicinal chemistry}, volume = {63}, number = {19}, pages = {10921-10945}, doi = {10.1021/acs.jmedchem.0c00763}, pmid = {32866008}, issn = {1520-4804}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Iron/metabolism ; Iron Chelating Agents/chemistry/pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism ; Pyridones/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {2-Heptyl-3-hydroxy-4(1H)-quinolone (PQS), a compound from P. aeruginosa, functions as both a quorum sensing (QS) regulator and a potent iron chelator to induce expression of pyoverdine and pyochelin which are involved in high-affinity iron transport systems. A potential dual-acting antibiofilm strategy requires molecules designed to interfere with iron uptake and the QS system of P. aeruginosa. A series of 2-substituted 3-hydroxy-1,6-dimethylpyridin-4-ones have been designed, synthesized, and tested as biofilm inhibitors of P. aeruginosa. One compound, N-((1,3,6-trimethyl-4-oxo-1,4-dihydropyridin-2-yl)methyl)hexanamide (10d), exhibits 68.67% biofilm inhibitory activity at 20 μM. Further mechanistic studies have confirmed that this compound not only inhibits the QS systems of P. aeruginosa but also acts as an iron chelator to compete strongly with pyoverdine, causing iron deficiency in bacteria. The pyoverdine receptor FpvA was revealed as the target of 10d by the Pvds mutant strain, fpvA-overexpressed strain, and in silico studies.}, } @article {pmid32865612, year = {2020}, author = {Cai, YM and Webb, JS}, title = {Optimization of nitric oxide donors for investigating biofilm dispersal response in Pseudomonas aeruginosa clinical isolates.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {20}, pages = {8859-8869}, pmid = {32865612}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Cystic Fibrosis ; Humans ; Nitric Oxide Donors/pharmacology ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; }, abstract = {Pseudomonas aeruginosa biofilms contribute heavily to chronic lung infection in cystic fibrosis patients, leading to morbidity and mortality. Nitric oxide (NO) has been shown to disperse P. aeruginosa biofilms in vitro, ex vivo and in clinical trials as a promising anti-biofilm agent. Traditional NO donors such as sodium nitroprusside (SNP) have been extensively employed in different studies. However, the dosage of SNP in different studies was not consistent, ranging from 500 nM to 500 μM. SNP is light sensitive and produces cyanide, which may lead to data misinterpretation and inaccurate predictions of dispersal responses in clinical settings. New NO donors and NO delivery methods have therefore been explored. Here we assessed 7 NO donors using P. aeruginosa PAO1 and determined that SNP and Spermine NONOate (S150) successfully reduced > 60% biomass within 24 and 2 h, respectively. While neither dosage posed toxicity towards bacterial cells, chemiluminescence assays showed that SNP only released NO upon light exposure in M9 media and S150 delivered much higher performance spontaneously. S150 was then tested on 13 different cystic fibrosis P. aeruginosa (CF-PA) isolates; most CF-PA biofilms were significantly dispersed by 250 μM S150. Our work therefore discovered a commercially available NO donor S150, which disperses CF-PA biofilms efficiently within a short period of time and without releasing cyanide, as an alternative of SNP in clinical trials in the future. KEY POINTS: • S150 performs the best in dispersing P. aeruginosa biofilms among 7 NO donors. • SNP only releases NO in the presence of light, while S150 releases NO spontaneously. • S150 successfully disperses biofilms formed by P. aeruginosa cystic fibrosis clinical isolates.}, } @article {pmid32865425, year = {2021}, author = {Fei, P and Xie, Q and Jiang, Y and Feng, H and Chang, Y and Kang, H and Xing, M and Chen, J}, title = {Genotyping, Antimicrobial Susceptibility and Biofilm Formation of Bacillus cereus Isolated from Powdered Food Products in China.}, journal = {Foodborne pathogens and disease}, volume = {18}, number = {1}, pages = {8-15}, doi = {10.1089/fpd.2020.2802}, pmid = {32865425}, issn = {1556-7125}, mesh = {Bacillus cereus/genetics/*isolation & purification/physiology ; Biofilms/*growth & development ; China ; Drug Resistance, Bacterial/*physiology ; Food Contamination/*analysis ; Food Microbiology ; Foods, Specialized/*microbiology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phylogeny ; Powders ; }, abstract = {This study was conducted to reveal the genotyping, antimicrobial susceptibility, and biofilm formation of Bacillus cereus isolated from powdered food products in China. Five hundred powdered food samples were collected from five provinces in China: 100 samples each of powdered infant formula (PIF), soy milk powder (SMP), lotus root powder (LRP), walnut powder (WP), and rice flour (RF). The genotyping of isolates was analyzed using multilocus sequence typing; meanwhile, antimicrobial susceptibility, and ability of biofilms formation on stainless steel tube of isolates were evaluated. Forty-two B. cereus strains were detected with an overall contamination rate of 8.4%, as well as, the highest B. cereus contamination rate was found in SMP (10%), followed by LRP (9%), WP (9%), RF (8%), and PIF (6%). These isolates were divided into 22 sequence types (STs); among them, ST32 (4/42, 9.5%) was the predominant ST. Phylogenetic relationships showed that the 42 strains of B. cereus were divided into three groups (group I, group II, and group III). Antimicrobial susceptibility testing indicated that all isolates were susceptible to tetracycline, gentamicin, erythromycin, and chloramphenicol, while resistant to ampicillin, cefepime, oxacillin, and rifampin. The analysis of ability of biofilm formation on stainless steel tube showed optical density (OD)595 value of 66.7% of B. cereus isolates was greater than 1. The OD595 level of isolates belonging to group III was higher compared with the other two groups, and OD595 values of B. cereus HB1 and HN5 were greater than 2. These findings improved the understanding of the characteristics of B. cereus isolated from powdered food products in China, and provided a theoretical basis for the prevention and control of B. cereus in food industry.}, } @article {pmid32862759, year = {2021}, author = {Thüring, M and Ganapathy, S and Schlüter, MAC and Lechner, M and Hartmann, RK}, title = {6S-2 RNA deletion in the undomesticated B. subtilis strain NCIB 3610 causes a biofilm derepression phenotype.}, journal = {RNA biology}, volume = {18}, number = {1}, pages = {79-92}, pmid = {32862759}, issn = {1555-8584}, mesh = {Bacillus subtilis/*genetics/*growth & development ; Biofilms/*growth & development ; *Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genetic Association Studies ; Genotype ; *Phenotype ; RNA, Bacterial/*genetics ; RNA, Messenger ; RNA, Untranslated/*genetics ; Spores, Bacterial ; }, abstract = {Bacterial 6S RNA regulates transcription via binding to the active site of RNA polymerase holoenzymes. 6S RNA has been identified in the majority of bacteria, in most cases encoded by a single gene. Firmicutes including Bacillus subtilis encode two 6S RNA paralogs, 6S-1 and 6S-2 RNA. Hypothesizing that the regulatory role of 6S RNAs may be particularly important under natural, constantly changing environmental conditions, we constructed 6S RNA deletion mutants of the undomesticated B. subtilis wild-type strain NCIB 3610. We observed a strong phenotype for the ∆6S-2 RNA strain that showed increased biofilm formation on solid media and the ability to form surface-attached biofilms in liquid culture. This phenotype remained undetected in derived laboratory strains (168, PY79) that are defective in biofilm formation. Quantitative RT-PCR data revealed transcriptional upregulation of biofilm marker genes such as tasA, epsA and bslA in the ∆6S-2 RNA strain, particularly during transition from exponential to stationary growth phase. Salt stress, which blocks sporulation at a very early stage, was found to override the derepressed biofilm phenotype of the ∆6S-2 RNA strain. Furthermore, the ∆6S-2 RNA strain showed retarded swarming activity and earlier spore formation. Finally, the ∆6S-1&2 RNA double deletion strain showed a prolonged lag phase of growth under oxidative, high salt and alkaline stress conditions, suggesting that the interplay of both 6S RNAs in B. subtilis optimizes and fine-tunes transcriptomic adaptations, thereby contributing to the fitness of B. subtilis under the unsteady and temporarily harsh conditions encountered in natural habitats.}, } @article {pmid32862102, year = {2020}, author = {Tian, X and Schopf, A and Amaral-Stewart, B and Christensson, M and Morgan-Sagastume, F and Vincent, S and Delatolla, R}, title = {Anammox attachment and biofilm development on surface-modified carriers with planktonic- and biofilm-based inoculation.}, journal = {Bioresource technology}, volume = {317}, number = {}, pages = {124030}, doi = {10.1016/j.biortech.2020.124030}, pmid = {32862102}, issn = {1873-2976}, mesh = {Anaerobiosis ; *Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; Plankton ; Sewage ; }, abstract = {This study investigates the kinetics, attachment, biofilm development and anammox bacteria enrichment of a novel detached anammox biofilm inoculation method on non-modified virgin MBBR carriers and pre-seeded denitrifying carriers. The study compares these results to the more common use of attached anammox carriers for anammox MBBR inoculation. The anammox bacteria specific attachment-growth rates for virgin carriers inoculated with detached anammox biofilm mass were 38.1% greater for the first 25 days, leading to approximately 30% less time required to achieve complete biofilm coverage than those measured in attached biofilm carrier inoculated systems during the attachment and early biofilm growth stages. The biofilm thickness increase rate was also 52.3% higher for virgin carriers with detached biofilm inoculum. Further, inoculation using pre-seeded denitrifying carriers compared to virgin carriers demonstrated a 13.8% preferential increase in anammox bacteria specific attachment-growth rate and a corresponding 47.2% higher NH4[+]-N removal rate at the time of biofilm maturation.}, } @article {pmid32861933, year = {2020}, author = {Uroosa, and Kazmi, SSUH and Xu, G and Xu, H}, title = {Insights into the effects of harmful algal bloom on ecological quality status using body-size spectrum of biofilm-dwelling ciliates in marine ecosystems.}, journal = {Marine pollution bulletin}, volume = {160}, number = {}, pages = {111596}, doi = {10.1016/j.marpolbul.2020.111596}, pmid = {32861933}, issn = {1879-3363}, mesh = {Biofilms ; *Ciliophora ; *Dinoflagellida ; Ecosystem ; Harmful Algal Bloom ; }, abstract = {The effects of two harmful algae Alexandrium tamarense and Gymnodinium catenatum on ecological quality status were identified using biofilm-dwelling ciliate assemblage as test organism communities. The body-size spectra of the test ciliates were observed at a gradient of cell concentrations of both algal species: 10[0] (control), followed by10[2], 10[3], 10[4] and 10[5] cells ml[-1]. The test ciliates showed clear variations in body-size spectra along the concentration gradients of both algal species. In terms of probability density, the ciliates generally peaked at low levels of algal concentrations (10[0]-10[4] cells ml[-1]) in small size forms, followed by the forms with large sizes at the concentration of 10[5] cells ml[-1] of both algal species. Bootstrapped-average analysis demonstrated a significant change in body-size spectrum when algal concentrations were higher than 10[4] cells ml[-1]. It is suggested that the body-size spectrum of the ciliates may be used to indicate the effects of harmful algal bloom.}, } @article {pmid32861003, year = {2020}, author = {Zhou, X and Wang, G and Ge, D and Yin, Z}, title = {Development of aerobic methane oxidation, denitrification coupled to methanogenesis (AMODM) in a microaerophilic expanded granular sludge blanket biofilm reactor.}, journal = {Journal of environmental management}, volume = {275}, number = {}, pages = {111280}, doi = {10.1016/j.jenvman.2020.111280}, pmid = {32861003}, issn = {1095-8630}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Methane ; Nitrogen ; Oxidation-Reduction ; Prospective Studies ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {The issue of enhancing nitrogen removal and managing dissolved methane emission in anaerobic treatment systems is a major bottleneck in its wider application to treat high-strength organic wastewater with nitrate. Herein, a novel aerobic methane oxidation, denitrification coupled to methanogenesis (AMODM) process was developed in a glucose-fed microaerobic expanded granular sludge blanket biofilm reactor (EGSBBR) through in-situ utilization of produced methane for nitrogen removal. The 162-day operation demonstrated that long-term treatment performance under the decreased COD/NO3[-]-N (C/N) ratio from 66.7 to 10 and the optimal C/N ratio for completing AMODM was found to be 16.7. Microbial community analysis further evidenced that Methanothrix as key methanogen predominated in the sludge bed, while Methlogaea as aerobic methane oxidizer was mainly detected in the packing bed of the hybrid system. Meanwhile, some facultative heterotrophic and dissimilated nitrate-reduction (DNRA) genera also co-existed. The profiling of key functional genes further proved concurrent occurrence of methanogenesis, aerobic methane oxidation and denitrification. Furthermore, possible microbial mechanism on AMODM process was elucidated from the prospective of targeted species interaction within the reactor. This research provides a robust and environment-friendly alternative process treating nitrate-containing organic wastewater towards efficient nitrogen removal, low resource consumption, bioenergy recovery and greenhouse gas reduction.}, } @article {pmid32859056, year = {2020}, author = {Campana, R and Mangiaterra, G and Tiboni, M and Frangipani, E and Biavasco, F and Lucarini, S and Citterio, B}, title = {A Fluorinated Analogue of Marine Bisindole Alkaloid 2,2-Bis(6-bromo-1H-indol-3-yl)ethanamine as Potential Anti-Biofilm Agent and Antibiotic Adjuvant Against Staphylococcus aureus.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {13}, number = {9}, pages = {}, pmid = {32859056}, issn = {1424-8247}, support = {DISB_FRANGIPANI_PROG_SIC_ALIMENTARE//Department of Biomolecular Sciences (DISB), University of Urbino Carlo Bo/ ; }, abstract = {Methicillin resistant Staphylococcus aureus (MRSA) infections represent a major global healthcare problem. Therapeutic options are often limited by the ability of MRSA strains to grow as biofilms on medical devices, where antibiotic persistence and resistance is positively selected, leading to recurrent and chronic implant-associated infections. One strategy to circumvent these problems is the co-administration of adjuvants, which may prolong the efficacy of antibiotic treatments, by broadening their spectrum and lowering the required dosage. The marine bisindole alkaloid 2,2-bis(6-bromo-1H-indol-3-yl)ethanamine (1) and its fluorinated analogue (2) were tested for their potential use as antibiotic adjuvants and antibiofilm agents against S. aureus CH 10850 (MRSA) and S. aureus ATCC 29213 (MSSA). Both compounds showed antimicrobial activity and bisindole 2 enabled 256-fold reduction (ΣFICs = 0.5) in the minimum inhibitory concentration (MIC) of oxacillin for the clinical MRSA strain. In addition, these molecules inhibited biofilm formation of S. aureus strains, and compound 2 showed greater eradicating activity on preformed biofilm compared to 1. None of the tested molecules exerted a viable but non-culturable cells (VBNC) inducing effect at their MIC values. Moreover, both compounds exhibited no hemolytic activity and a good stability in plasma, indicating a non-toxic profile, hence, in particular compound 2, a potential for in vivo applications to restore antibiotic treatment against MRSA infections.}, } @article {pmid32856923, year = {2020}, author = {Cui, T and Wu, S and Sun, Y and Ren, J and Qu, X}, title = {Self-Propelled Active Photothermal Nanoswimmer for Deep-Layered Elimination of Biofilm In Vivo.}, journal = {Nano letters}, volume = {20}, number = {10}, pages = {7350-7358}, doi = {10.1021/acs.nanolett.0c02767}, pmid = {32856923}, issn = {1530-6992}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Gold ; *Metal Nanoparticles ; Phototherapy ; *Staphylococcus aureus ; }, abstract = {Increasing penetration of antibacterial agents into biofilm is a promising strategy for improvement of therapeutic effect and slowdown of the progression of antibiotic resistance. Herein, we design a near-infrared (NIR) light-driven nanoswimmer (HSMV). Under NIR light irradiation, HSMV performs efficient self-propulsion and penetrates into the biofilm within 5 min due to photothermal conversion of asymmetrically distributed AuNPs. The localized thermal (∼45 °C) and thermal-triggered release of vancomycin (Van) leads to an efficient combination of photothermal therapy and chemotherapy in one system. The active motion of HSMV increases the effective distance of photothermal therapy (PTT) and also improves the therapeutic index of the antibiotic, resulting in superior biofilm removal rate (>90%) in vitro. Notably, HSMV can eliminate S. aureus biofilms grown in vivo under 10 min of laser irradiation without damage to healthy tissues. This work may shed light on therapeutic strategies for in vivo treatment of biofilm-associated infections.}, } @article {pmid32856330, year = {2020}, author = {Desbois, AP and Cook, KJ and Buba, E}, title = {Antibiotics modulate biofilm formation in fish pathogenic isolates of atypical Aeromonas salmonicida.}, journal = {Journal of fish diseases}, volume = {43}, number = {11}, pages = {1373-1379}, doi = {10.1111/jfd.13232}, pmid = {32856330}, issn = {1365-2761}, support = {//Commonwealth Scholarship Commission/ ; //University of Stirling/ ; }, mesh = {Aeromonas salmonicida/*drug effects/growth & development ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Oxytetracycline/pharmacology ; Thiamphenicol/analogs & derivatives/pharmacology ; }, abstract = {Atypical Aeromonas salmonicida causes furunculosis infections of non-salmonid fish, which requires antibiotic therapy. However, antibiotics may induce biofilm in some bacteria, which protects them against hostile conditions while allowing them to persist on surfaces, thus forming a reservoir for infection. The aim of this study was to determine whether atypical isolates of A. salmonicida increased biofilm in the presence of two antibiotics, florfenicol and oxytetracycline. A microtitre plate assay was used to quantify biofilm in the presence and absence of each antibiotic. Fifteen of 28 isolates formed biofilms under control conditions, while 23 of 28 isolates increased biofilm formation in the presence of at least one concentration of at least one antibiotic. For oxytetracycline, the most effective concentration causing biofilm to increase was one-quarter of that preventing visible bacterial growth, whereas for florfenicol it was one-half of this value. This is the first study to demonstrate that a bacterial pathogen of fish increases biofilm in response to antibiotics. Biofilm formation may increase the risk of re-infection in culture systems and this lifestyle favours the transmission of genetic material, which has implications for the dissemination of antibiotic-resistance genes and demonstrates the need for enhanced disease prevention measures against atypical A. salmonicida.}, } @article {pmid32854286, year = {2020}, author = {Doghri, I and Portier, E and Desriac, F and Zhao, JM and Bazire, A and Dufour, A and Rochette, V and Sablé, S and Lanneluc, I}, title = {Anti-Biofilm Activity of a Low Weight Proteinaceous Molecule from the Marine Bacterium Pseudoalteromonas sp. IIIA004 against Marine Bacteria and Human Pathogen Biofilms.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32854286}, issn = {2076-2607}, support = {CPER littoral 2007-14//CPER/ ; EC2CO program MicroBiEn 2013-14//CNRS/ ; Région Poitou-Charente//Région Poitou-Charente/ ; Région Bretagne//Région Bretagne/ ; Conseil Général de la Charente Maritime (PhD grant)//Conseil Général de la Charente Maritime/ ; FEDER//FEDER/ ; }, abstract = {Pseudoalteromonas bacteria are known as potential bioactive metabolite producers. Because of the need to obtain natural molecules inhibiting the bacterial biofilms, we investigated the biofilm inhibitory activity of the marine bacterium Pseudoalteromonas sp. IIIA004 against the pioneer surface colonizer Roseovarius sp. VA014. The anti-biofilm activity from the culture supernatant of Pseudoalteromonas sp. IIIA004 (SNIIIA004) was characterized in microtiter plates (static conditions/polystyrene surface) and in flow cell chambers (dynamic conditions/glass surface). The Pseudoalteromonas exoproducts exhibited an inhibition of Roseovarius sp. VA014 biofilm formation as well as a strong biofilm dispersion, without affecting the bacterial growth. Microbial adhesion to solvent assays showed that SNIIIA004 did not change the broad hydrophilic and acid character of the Roseovarius strain surface. Bioassay-guided purification using solid-phase extraction and C18 reverse-phase-high-performance liquid chromatography (RP-HPLC) was performed from SNIIIA004 to isolate the proteinaceous active compound against the biofilm formation. This new anti-biofilm low weight molecule (< 3kDa), named P004, presented a wide spectrum of action on various bacterial biofilms, with 71% of sensitive strains including marine bacteria and human pathogens. Pseudoalteromonas sp. IIIA004 is a promising source of natural anti-biofilm compounds that combine several activities.}, } @article {pmid32853527, year = {2021}, author = {Wan, SX and Tian, J and Liu, Y and Dhall, A and Koo, H and Hwang, G}, title = {Cross-Kingdom Cell-to-Cell Interactions in Cariogenic Biofilm Initiation.}, journal = {Journal of dental research}, volume = {100}, number = {1}, pages = {74-81}, pmid = {32853527}, issn = {1544-0591}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE027970/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Candida albicans ; Cell Communication ; Streptococcus gordonii ; *Streptococcus mutans ; }, abstract = {Candida albicans is known to form polymicrobial biofilms with various Streptococcus spp., including mitis and mutans group streptococci. Streptococcus gordonii (mitis group) has been shown to bind avidly to C. albicans hyphae via direct cell-to-cell interaction, while the cariogenic pathogen Streptococcus mutans (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between S. mutans (or S. gordonii) and C. albicans in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that S. gordonii binding force to the C. albicans surface is significantly higher than that ofS. mutans to the fungal surface (~2-fold). However, S. mutans binding forces are dramatically enhanced when the C. albicans cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated C. albicans), which vastly exceeds the forces between S. gordonii andC. albicans. The enhanced binding affinity of S. mutans to glucan-coated C. albicans resulted in a larger structure during early biofilm initiation compared to S. gordonii-C. albicans biofilms. Ultimately, this resulted in S. mutans dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of Candida-streptococcal interaction whereby extracellular glucans may selectively favor S. mutans binding interactions with C. albicans during cariogenic biofilm development.}, } @article {pmid32853401, year = {2021}, author = {Schuldt, L and Bi, J and Owen, G and Shen, Y and Haapasalo, M and Häkkinen, L and Larjava, H}, title = {Decontamination of rough implant surfaces colonized by multispecies oral biofilm by application of leukocyte- and platelet-rich fibrin.}, journal = {Journal of periodontology}, volume = {92}, number = {6}, pages = {875-885}, doi = {10.1002/JPER.20-0205}, pmid = {32853401}, issn = {1943-3670}, mesh = {Biofilms ; Decontamination ; Leukocytes ; *Platelet-Rich Fibrin ; Surface Properties ; Titanium ; }, abstract = {BACKGROUND: Decontamination of biofilm-infected rough implant surfaces is challenging. Platelet rich blood products have been shown to have anti-microbial properties against periodontal pathogens. Our aim was to investigate the effect of a potential biological implant surface disinfectant, leukocyte- and platelet-rich fibrin (L-PRF), on a mature oral multispecies biofilm on a rough titanium surface.

METHODS: Sandblasted, large grit, acid-etched (SLA) titanium disks were inoculated with subgingival dental plaque and cultured anaerobically for 21 days. The L-PRF membranes were collected from 12 donors in three trials (four donors in each trial). The disks were rinsed with 0.9% NaCl and exposed to the cell-rich portion of the L-PRF membranes for 48 hours followed by scanning electron microscope (SEM) analysis immediately or after rinsing with 0.9% NaCl prior to fixation. The presence of platelet factor-4 in the rinse samples was analyzed by Western blotting. Remaining bacteria were quantified from SEM images of the implant surfaces and their numbers statistically compared.

RESULTS: The L-PRF-treated samples without rinsing displayed numerous cells with multiple pseudopodia in immediate contact with bacteria that appeared perforated and increased in size. The cells were identified as platelets based on morphological criteria and by positive reaction for platelet factor-4 by Western blotting. After post-treatment rinsing, the L-PRF-treated disks displayed a significant reduction in bacterial counts (in average 92% reduction).

CONCLUSION: Application of L-PRF significantly reduced bacterial counts on contaminated SLA titanium surface, most likely through anti-microbial action by platelets.}, } @article {pmid32853235, year = {2020}, author = {Proano-Pena, G and Carrano, AL and Blersch, DM}, title = {Analysis of very-high surface area 3D-printed media in a moving bed biofilm reactor for wastewater treatment.}, journal = {PloS one}, volume = {15}, number = {8}, pages = {e0238386}, pmid = {32853235}, issn = {1932-6203}, mesh = {Ammonia/chemistry ; Bacteria/growth & development ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Mass Media ; Nitrates/chemistry ; Nitrification/physiology ; Nitrogen/chemistry ; Printing, Three-Dimensional ; Waste Disposal, Fluid/methods ; Wastewater/*analysis/*microbiology ; }, abstract = {Moving Bed Biofilm Reactors (MBBRs) can efficiently treat wastewater by incorporating suspended biocarriers that provide attachment surfaces for active microorganisms. The performance of MBBRs for wastewater treatment is, among other factors, contingent upon the characteristics of the surface area of the biocarriers. Thus, novel biocarrier topology designs can potentially increase MBBR performance in a significant manner. The goal of this work is to assess the performance of 3-D-printed biofilter media biocarriers with varying surface area designs for use in nitrifying MBBRs for wastewater treatment. Mathematical models, rendering, and 3D printing were used to design and fabricate gyroid-shaped biocarriers with a high degree of complexity at three different levels of specific surface area (SSA), generally providing greater specific surface areas than currently available commercial designs. The biocarriers were inoculated with a nitrifying bacteria community, and tested in a series of batch reactors for ammonia conversion to nitrate, in three different experimental configurations: constant fill ratio, constant total surface area, and constant biocarrier media count. Results showed that large and medium SSA gyroid biocarriers delivered the best ammonia conversion performance of all designs, and significantly better than that of a standard commercial design. The percentage of ammonia nitrogen conversion at 8 hours for the best performing biocarrier design was: 99.33% (large SSA gyroid, constant fill ratio), 94.74% (medium SSA gyroid, constant total surface area), and 92.73% (large SSA gyroid, constant biocarrier media count). Additionally, it is shown that the ammonia conversion performance was correlated to the specific surface area of the biocarrier, with the greatest rates of ammonia conversion (99.33%) and nitrate production (2.7 mg/L) for manufactured gyroid biocarriers with a specific surface area greater than 1980.5 m2/m3. The results suggest that the performance of commercial MBBRs for wastewater treatment can be greatly improved by manipulation of media design through topology optimization.}, } @article {pmid32851551, year = {2020}, author = {Majumdar, M and Dubey, A and Goswami, R and Misra, TK and Roy, DN}, title = {In vitro and in silico studies on the structural and biochemical insight of anti-biofilm activity of andrograpanin from Andrographis paniculata against Pseudomonas aeruginosa.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {10}, pages = {143}, doi = {10.1007/s11274-020-02919-x}, pmid = {32851551}, issn = {1573-0972}, support = {YSS/2015/001965//Science and Engineering Research Board/ ; }, mesh = {Andrographis/*chemistry ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/chemistry/drug effects ; Biofilms/*drug effects/growth & development ; Diterpenes/chemistry/*pharmacology ; Gentamicins/pharmacology ; Ligases ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/drug effects ; Secondary Metabolism ; Trans-Activators ; Transcription Factors ; Virulence Factors ; }, abstract = {Microbial infections have become a global threat to drug-tolerant phenomena due to their biofilm formatting capacity. In many cases, conventional antimicrobial drugs fail to combat the infection, thus necessitating the discovery of some alternative medicine. Over several decades, plant metabolites have played a critical role in treating a broad spectrum of microbial infections due to its low cytotoxicity. Andrograpanin, a secondary metabolite, is a diterpenoid present in the leaf of Andrographis paniculata. In this study, andrograpanin (0.15 mM) exhibited significant inhibition on biofilm production by Pseudomonas aeruginosa in the presence of gentamicin (0.0084 mM). The impaired production of extracellular polymeric substances and several virulence factors of Pseudomonas aeruginosa were investigated to understand the mechanism of action mediated by andrograpanin. The structural alteration of biofilm was evaluated by using fluorescence microscopy, atomic force microscopy and field emission scanning electron microscopy. The in silico molecular simulation studies predicted interaction of andrograpanin with quorum sensing proteins such as RhlI, LasI, LasR, and swarming motility protein BswR of Pseudomonas aeruginosa. Overall the studies indicate that andrograpanin could be used as a therapeutic molecule against biofilm development by Pseudomonas aeruginosa.}, } @article {pmid32850471, year = {2020}, author = {Zhang, K and Li, X and Yu, C and Wang, Y}, title = {Promising Therapeutic Strategies Against Microbial Biofilm Challenges.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {359}, pmid = {32850471}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents ; *Biofilms ; Extracellular Matrix ; Multicenter Studies as Topic ; }, abstract = {Biofilms are communities of microorganisms that are attached to a biological or abiotic surface and are surrounded by a self-produced extracellular matrix. Cells within a biofilm have intrinsic characteristics that are different from those of planktonic cells. Biofilm resistance to antimicrobial agents has drawn increasing attention. It is well-known that medical device- and tissue-associated biofilms may be the leading cause for the failure of antibiotic treatments and can cause many chronic infections. The eradication of biofilms is very challenging. Many researchers are working to address biofilm-related infections, and some novel strategies have been developed and identified as being effective and promising. Nevertheless, more preclinical studies and well-designed multicenter clinical trials are critically needed to evaluate the prospects of these strategies. Here, we review information about the mechanisms underlying the drug resistance of biofilms and discuss recent progress in alternative therapies and promising strategies against microbial biofilms. We also summarize the strengths and weaknesses of these strategies in detail.}, } @article {pmid32849437, year = {2020}, author = {Lyu, Z and Shang, Y and Wang, X and Wu, Y and Zheng, J and Liu, H and Gong, T and Ye, L and Qu, D}, title = {Monoclonal Antibodies Specific to the Extracellular Domain of Histidine Kinase YycG of Staphylococcus epidermidis Inhibit Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1839}, pmid = {32849437}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis is frequently associated with biofilm-related infections. Biofilms drastically reduce the efficacy of conventional antibiotics and the host immune system. In S. epidermidis biofilm formation, a major role is played by the YycG/YycF two-component system, and previous findings have indicated that inhibitors targeting the cytoplasmic HATPase_c domain of YycG kinase in S. epidermidis exhibit bactericidal and biofilm-killing activities. Therefore, we hypothesized that monoclonal antibodies (mAbs) against YycG extracellular (YycGex) domain would block the signal transduction and influence the biofilm formation of S. epidermidis. In this study, we screened out two YycGex-specific mAbs showing the highest affinity for the target, mAbs 2F3 and 1H1. These mAbs inhibited S. epidermidis biofilm formation in a dose-dependent manner, and at a concentration of 160 μg/mL, mAbs 2F3 and 1H1 caused 78.3 and 93.1% biofilm reduction, respectively, relative to normal mouse IgG control. When co-cultivated with YycGex mAbs, S. epidermidis cells showed diminished initial-adherence capacity, and the antibody treatment further led to a marked decrease in the synthesis of polysaccharide intercellular adhesin and in the transcriptional level of genes encoding proteins involved in biofilm formation. Lastly, we determined that the epitopes recognized by the two YycGex mAbs are located within aa 59-70 of the YycGex domain. It indicates that the YycGex domain may be a potential candidate as a vaccine for the prevention of S. epidermidis biofilm infections.}, } @article {pmid32849390, year = {2020}, author = {Lisle, JT}, title = {Nutrient Removal and Uptake by Native Planktonic and Biofilm Bacterial Communities in an Anaerobic Aquifer.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1765}, pmid = {32849390}, issn = {1664-302X}, abstract = {Managed aquifer recharge (MAR) offers a collection of water storage and storage options that have been used by resource managers to mitigate the reduced availability of fresh water. One of these technologies is aquifer storage and recovery (ASR), where surface water is treated then recharged into a storage zone within an existing aquifer for later recovery and discharge into a body of water. During the storage phase of ASR, nutrient concentrations in the recharge water have been shown to decrease due, presumably via the uptake by the native aquifer microbial community. In this study, the native microbial community in an anaerobic carbonate aquifer zone targeted for ASR storage was segregated into planktonic and biofilm communities then challenged with NO3-N, PO4-P, and acetate as dissolved organic carbon (DOC) to determine their respective removal and uptake rates. The planktonic community removed NO3-N at a rate of 0.059 mg L[-1]d[-1], PO4-P at 5.73 × 10[-8]-1.03 × 10[-7] mg L[-1]d[-1] and DOC at 0.015-0.244 mg L[-1]d[-1]. The biofilm community was significantly more proficient, removing NO3-N at 0.116 mg L[-1]d[-1] (1.6-9.0 μg m[-2]d[-1]), PO4-P at 4.20-5.91 × 10[-5] mg L[-1]d[-1] (2.47-9.88 ng m[-2]d[-1]) and DOC at 0.301-0.696 mg L[-1]d[-1] (29.0-71.0 μg m[-2]d[-1]). Additionally, the PO4-P sorption rate onto the carbonate aquifer matrix ranged from 1.64 × 10[-7] to 9.25 × 10[-7] mg PO4-P m[-2] day[-1]. These rates were applied to field data collected at an ASR facility in central Florida and from the same aquifer storage zone from which the biofilm communities were grown. With only 10% of the available surface area within the storage zone being colonized by biofilms, typical concentrations of NO3-N, PO4-P, and DOC in the recharged filtered surface waters would be reduced to below detection limits, and by 81.4 and 91.1%, respectively, during a 150 days storage period.}, } @article {pmid32849352, year = {2020}, author = {Al-Shabib, NA and Husain, FM and Qais, FA and Ahmad, N and Khan, A and Alyousef, AA and Arshad, M and Noor, S and Khan, JM and Alam, P and Albalawi, TH and Shahzad, SA}, title = {Phyto-Mediated Synthesis of Porous Titanium Dioxide Nanoparticles From Withania somnifera Root Extract: Broad-Spectrum Attenuation of Biofilm and Cytotoxic Properties Against HepG2 Cell Lines.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1680}, pmid = {32849352}, issn = {1664-302X}, abstract = {There is grave necessity to counter the menace of drug-resistant biofilms of pathogens using nanomaterials. Moreover, we need to produce nanoparticles (NPs) using inexpensive clean biological approaches that demonstrate broad-spectrum inhibition of microbial biofilms and cytotoxicity against HepG2 cell lines. In the current research work, titanium dioxide (TiO2) NPs were fabricated through an environmentally friendly green process using the root extract of Withania somnifera as the stabilizing and reducing agent to examine its antibiofilm and anticancer potential. Further, X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron micrograph (TEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) techniques were used for determining the crystallinity, functional groups involved, shape, size, thermal behavior, surface area, and porosity measurement, respectively, of the synthesized TiO2 NPs. Antimicrobial potential of the TiO2 NPs was determined by evaluating the minimum inhibitory concentration (MIC) against Escherichia coli, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Listeria monocytogenes, Serratia marcescens, and Candida albicans. Furthermore, at levels below the MIC (0.5 × MIC), TiO2 NPs demonstrated significant inhibition of biofilm formation (43-71%) and mature biofilms (24-64%) in all test pathogens. Cell death due to enhanced reactive oxygen species (ROS) production could be responsible for the impaired biofilm production in TiO2 NP-treated pathogens. The synthesized NPs induced considerable reduction in the viability of HepG2 in vitro and could prove effective in controlling liver cancer. In summary, the green synthesized TiO2 NPs demonstrate multifarious biological properties and could be used as an anti-infective agent to treat biofilm-based infections and cancer.}, } @article {pmid32849349, year = {2020}, author = {Munsch-Alatossava, P and Alatossava, T}, title = {Potential of N2 Gas Flushing to Hinder Dairy-Associated Biofilm Formation and Extension.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1675}, pmid = {32849349}, issn = {1664-302X}, abstract = {Worldwide, the dairy sector remains of vital importance for food production despite severe environmental constraints. The production and handling conditions of milk, a rich medium, promote inevitably the entrance of microbial contaminants, with notable impact on the quality and safety of raw milk and dairy products. Moreover, the persistence of high concentrations of microorganisms (especially bacteria and bacterial spores) in biofilms (BFs) present on dairy equipment or environments constitutes an additional major source of milk contamination from pre- to post-processing stages: in dairies, BFs represent a major concern regarding the risks of disease outbreaks and are often associated with significant economic losses. One consumption trend toward "raw or low-processed foods" combined with current trends in food production systems, which tend to have more automation and longer processing runs with simultaneously more stringent microbiological requirements, necessitate the implementation of new and obligatory sustainable strategies to respond to new challenges regarding food safety. Here, in light of studies, performed mainly with raw milk, that considered dominant "planktonic" conditions, we reexamine the changes triggered by cold storage alone or combined with nitrogen gas (N2) flushing on bacterial populations and discuss how the observed benefits of the treatment could also contribute to limiting BF formation in dairies.}, } @article {pmid32849347, year = {2020}, author = {Vazquez-Munoz, R and Lopez, FD and Lopez-Ribot, JL}, title = {Silver Nanoantibiotics Display Strong Antifungal Activity Against the Emergent Multidrug-Resistant Yeast Candida auris Under Both Planktonic and Biofilm Growing Conditions.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1673}, pmid = {32849347}, issn = {1664-302X}, abstract = {Candida auris is an emergent multidrug-resistant pathogenic yeast with an unprecedented ability for a fungal organism to easily spread between patients in clinical settings, leading to major outbreaks in healthcare facilities. The formation of biofilms by C. auris contributes to infection and its environmental persistence. Most antifungals and sanitizing procedures are not effective against C. auris, but antimicrobial nanomaterials could represent a viable alternative to combat the infections caused by this emerging pathogen. We have previously described an easy and inexpensive method to synthesize silver nanoparticles (AgNPs) in non-specialized laboratories. Here, we have assessed the antimicrobial activity of the resulting AgNPs on C. auris planktonic and biofilm growth phases. AgNPs displayed a strong antimicrobial activity against all the stages of all C. auris strains tested, representative of four different clades. Under planktonic conditions, minimal inhibitory concentration (MIC) values of AgNPs against the different strains were <0.5 μg ml[-1]; whereas calculated IC50 values for inhibition of biofilms formation were <2 μg ml[-1] for all, but one of the C. auris strains tested. AgNPs were also active against preformed biofilms formed by all different C. auris strains, with IC50 values ranging from 1.2 to 6.2 μg ml[-1]. Overall, our results indicate potent activity of AgNPs against strains of C. auris, both under planktonic and biofilm growing conditions, and indicate that AgNPs may contribute to the control of infections caused by this emerging nosocomial threat.}, } @article {pmid32849336, year = {2020}, author = {Wischer, D and Schneider, D and Poehlein, A and Herrmann, F and Oruc, H and Meinhardt, J and Wagner, O and Ahmed, R and Kharin, S and Novikova, N and Haag, R and Daniel, R and Grohmann, E}, title = {Novel Antimicrobial Cellulose Fleece Inhibits Growth of Human-Derived Biofilm-Forming Staphylococci During the SIRIUS19 Simulated Space Mission.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1626}, pmid = {32849336}, issn = {1664-302X}, abstract = {Two novel antimicrobial surface coatings were assessed for their lasting antibacterial effect under simulated space conditions during the SIRIUS-19 study. Because long-term space travel can affect the human immune system, astronauts are particularly susceptible to infectious disease. Moreover, the space flight environment can alter the composition of microbial communities within the spacecraft and increase bacterial virulence and resistance to antibiotics. In addition to protecting the crew from infection by human pathogens, prevention and elimination of bacterial contamination is important to avoid corrosion and damage of the technical equipment. The antimicrobial coating AGXX[®] consists of micro-galvanic cells composed of silver and ruthenium which damage bacterial cells through the release of reactive oxygen species. Over the last years, several studies on the antimicrobial effect of AGXX[®] have demonstrated an effective inhibition of growth and even complete elimination of many pathogenic bacteria - including multiresistant microorganisms - as well as their biofilms. The second antimicrobial coating, GOX, consists of chemically modified graphene oxide. Through a positive surface charge and its flexible scaffold, GOX can multivalently bind and immobilize bacteria via electrostatic attraction. Here, AGXX[®] and GOX were applied to non-metallic carriers not previously tested. The antimicrobial coated materials, as well as uncoated control samples, were exposed in the SIRIUS artificial space module and analyzed at different time points during the 4-months isolation study. Survival and growth of airborne heterotrophic, aerobic bacteria on the surfaces were assessed by cultivation-based methods, employing growth conditions suitable for potential human pathogens. Human-associated, biofilm-forming Staphylococcus spp. (S. hominis, S. haemolyticus, and S. epidermidis) strongly dominated at all time points, most were resistant against erythromycin, kanamycin, and ampicillin. AGXX[®] coatings completely inhibited growth of these opportunistic pathogens on all tested surface materials. Particularly, AGXX[®]-cellulose fleece achieved a clear reduction in bacterial load able to recover post contact. GOX-cellulose fleece effectively immobilized bacteria. Sequence analysis of 16S rRNA gene amplicons revealed that the isolated Staphylococcus spp. did not dominate the overall bacterial community, accounting for only 0.1-0.4% of all sequences. Instead, molecular data revealed Lactobacillus, Comamonas, Pseudomonas, Sporosarcina, and Bacillus as the dominant genera across all samples and time points.}, } @article {pmid32849331, year = {2020}, author = {Yang, Y and Chen, F and Chen, HY and Peng, H and Hao, H and Wang, KJ}, title = {A Novel Antimicrobial Peptide Scyreprocin From Mud Crab Scylla paramamosain Showing Potent Antifungal and Anti-biofilm Activity.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1589}, pmid = {32849331}, issn = {1664-302X}, abstract = {Natural antimicrobial peptides (AMPs) are potential antibiotic alternatives. Marine crustaceans are thought to generate more powerful and various AMPs to protect themselves from infections caused by pathogenic microorganisms in their complex aquatic habitat, thus becoming one of the most promising sources of AMPs or other bioactive substances. In the study, a novel protein was identified as an interacting partner of male-specific AMP SCY2 in Scylla paramamosain and named scyreprocin. The recombinant product of scyreprocin (rScyreprocin) was successfully expressed in Escherichia coli. rScyreprocin exerted potent, broad-spectrum antifungal, antibacterial, and anti-biofilm activity (minimum inhibitory concentrations from 0.5 to 32 μM) through differential modes of action, including disruption of cell membrane integrity and induction of cell apoptosis, and has rapid bactericidal (in 0.5-2 h) and fungicidal (in 8-10 h) kinetics. In addition to its fungicidal activity against planktonic fungi, rScyreprocin also prevented the adhesion of fungal cells, inhibited biofilm formation, and eradicated the mature biofilms. Moreover, rScyreprocin showed a profound inhibitory effect on spore germination of Aspergillus spp. (minimum inhibitory concentrations from 4 to 8 μM). This peptide was not cytotoxic to murine and mammalian cells and could increase the survival rate of Oryzias melastigma under the challenge of Vibrio harveyi. Taken together, the novel AMP scyreprocin would be a promising alternative to antibiotics used in aquaculture and medicine.}, } @article {pmid32849322, year = {2020}, author = {Liu, W and Wu, Z and Mao, C and Guo, G and Zeng, Z and Fei, Y and Wan, S and Peng, J and Wu, J}, title = {Antimicrobial Peptide Cec4 Eradicates the Bacteria of Clinical Carbapenem-Resistant Acinetobacter baumannii Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1532}, pmid = {32849322}, issn = {1664-302X}, abstract = {The drug resistance rate of Acinetobacter baumannii increases year on year, and the drugs available for the treatment of carbapenem-resistant A. baumannii (CRAB) infection are extremely limited. A. baumannii, which forms biofilms, protects itself by secreting substrates such as exopolysaccharides, allowing it to survive under adverse conditions and increasing drug resistance. Antimicrobial peptides are small molecular peptides with broad-spectrum antibacterial activity and immunomodulatory function. Previous studies have shown that the antimicrobial peptide Cec4 has a strong effect on A. baumannii, but the antibacterial and biofilm inhibition of this antimicrobial peptide on clinical carbapenem resistance A. baumannii is not thoroughly understood. In this study, it was indicated that most of the 200 strains of CRAB were susceptible to Cec4 with a MIC of 4 μg/ml. Cec4 has a strong inhibitory and eradication effect on the CRAB biofilm; the minimum biofilm inhibition concentration (MBIC) was 64-128 μg/ml, and the minimum biofilm eradication concentration (MBEC) was 256-512 μg/ml. It was observed that Cec4 disrupted the structure of the biofilm using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). A comparative transcriptome analysis of the effects of the antimicrobial peptide Cec4 on CRAB biofilm, identified 185 differentially expressed genes, including membrane proteins, bacterial resistance genes, and pilus-related genes. The results show that multiple metabolic pathways, two-component regulation systems, quorum sensing, and antibiotic synthesis-related pathways in A. baumannii biofilms were affected after Cec4 treatment. In conclusion, Cec4 may represent a new choice for the prevention and treatment of clinical infections, and may also provide a theoretical basis for the development of antimicrobial peptide drugs.}, } @article {pmid32849320, year = {2020}, author = {Cambronel, M and Nilly, F and Mesguida, O and Boukerb, AM and Racine, PJ and Baccouri, O and Borrel, V and Martel, J and Fécamp, F and Knowlton, R and Zimmermann, K and Domann, E and Rodrigues, S and Feuilloley, M and Connil, N}, title = {Influence of Catecholamines (Epinephrine/Norepinephrine) on Biofilm Formation and Adhesion in Pathogenic and Probiotic Strains of Enterococcus faecalis.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1501}, pmid = {32849320}, issn = {1664-302X}, abstract = {Enterococcus faecalis has controversial status due to its emerging role in nosocomial infections, while some strains with beneficial effects are used as probiotics and starter cultures in dairy industry. These bacteria can be found as resident or transient germs in the gut or on skin, where they are continually exposed to various eukaryotic molecules. In this context, the aim of our work was to evaluate the effect of the catecholamine stress hormones, epinephrine (Epi), and norepinephrine (NE) on some Enterococcus strains. Four E. faecalis strains were included in this study: E. faecalis MMH594 and E. faecalis V583, pathogenic strains of clinical origin, E. faecalis Symbioflor 1 clone DSM 16431, a pharmaceutical probiotic, and E. faecalis OB15, a probiotic strain previously isolated from Tunisian rigouta (Baccouri et al., 2019). Epi was found to modulate the formation of biofilm (biovolume and thickness) in E. faecalis, whether pathogens or probiotics. NE had less effect on biofilm formation of these bacteria. We also investigated the effect of Epi and NE on adhesion of E. faecalis to eukaryotic cells as it is the first step of colonization of the host. Epi was found to significantly enhance the adhesion of MMH594 and OB15 to Caco-2/TC7 intestinal cells and HaCaT keratinocyte cells, whereas NE significantly increased the adhesion of V583 and Symbioflor 1 DSM 16431 to Caco-2/TC7 cells, the adhesion of MMH594, Symbioflor 1 DSM 16431, and OB15 to HaCaT cells. Analysis of a putative adrenergic sensor of Epi/NE in E. faecalis, compared to QseC, the Escherichia coli adrenergic receptor, allowed the identification of VicK as the nearest protein to QseC with 29% identity and 46% similarity values. Structure modeling and molecular docking of VicK corroborated the hypothesis of possible interactions of this putative adrenergic sensor with Epi and NE, with binding energies of -4.08 and -4.49 kcal/mol, respectively. In conclusion, this study showed for the first time that stress hormones could increase biofilm formation and adhesion to eukaryotic cells in E. faecalis. Future experiments will aim to confirm by in vivo studies the role of VicK as adrenergic sensor in E. faecalis probiotic and pathogen strains. This may help to develop new strategies of antagonism/competition in the gut or skin ecological niches, and to prevent the colonization by opportunistic pathogens.}, } @article {pmid32848429, year = {2020}, author = {Rafaque, Z and Abid, N and Liaqat, N and Afridi, P and Siddique, S and Masood, S and Kanwal, S and Dasti, JI}, title = {In-vitro Investigation of Antibiotics Efficacy Against Uropathogenic Escherichia coli Biofilms and Antibiotic Induced Biofilm Formation at Sub-Minimum Inhibitory Concentration of Ciprofloxacin.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {2801-2810}, pmid = {32848429}, issn = {1178-6973}, abstract = {BACKGROUND: Community-acquired urinary tract infections are associated with significant morbidity, and uropathogenic Escherichia coli (UPEC) alone causes 90% of urinary tract infections. This bacterium retains a diverse armament of virulence factors including fimbria, hemolysins, and siderophores production. In a post invasion scenario, formation of intracellular communities mimic biofilm-like characteristics and are linked to recurrent urinary tract infections. We investigated the effects of different frontline antibiotics on the formation, inhibition, and eradication of biofilms of virulent UPEC strains.

MATERIALS AND METHODS: A total of 155 UPEC strains were scrutinized for various virulence factors including gelatinase, cell surface hydrophobicity, hemagglutination, and serum bactericidal activity. Biofilm formation was confirmed by three different methods: Congo red agar, test tube, and tissue culture plate method. Biofilm inhibition and eradication assays were performed according to the standard protocols. Topographical analysis of biofilms was done by scanning electronic microscopy (SEM).

RESULTS: Out of 155 strains, 113 (73%) were strong biofilm formesr, while 37 (24%) produced biofilms at moderate level. Significant differences were observed between MICs of planktonic cells (MIC-p) and MICs of UPEC biofilms (MIC-b). Among tested frontline antibiotics, levofloxacin successfully inhibited biofilms at a concentration of 32 µg/mL, while trimethoprim eradicated biofilms at higher concentrations (512-1024 µg/mL). Ciprofloxacin treatment at sub-MIC level significantly enhanced biofilm formation (P<0.05).

CONCLUSION: The majority of UPEC strains are strong biofilm formers and show higher tolerance towards frontline antibiotics in biofilm form. We observed significant inhibitory effects of levofloxacin (32 µg/mL) on UPEC biofilms, while treatment with sub-minimal concentrations of ciprofloxacin significantly enhanced biofilm formation. Out of all tested antibiotics, trimethoprim (512-1024 µg/mL) eradicated UPEC biofilms.}, } @article {pmid32848055, year = {2020}, author = {Kowalski, CH and Morelli, KA and Schultz, D and Nadell, CD and Cramer, RA}, title = {Fungal biofilm architecture produces hypoxic microenvironments that drive antifungal resistance.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {36}, pages = {22473-22483}, pmid = {32848055}, issn = {1091-6490}, support = {R01 AI130128/AI/NIAID NIH HHS/United States ; P20 GM113132/GM/NIGMS NIH HHS/United States ; R01 AI146121/AI/NIAID NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; F31 AI138354/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/*pharmacology ; *Aspergillus fumigatus/drug effects/physiology ; Biofilms/*drug effects ; Cell Hypoxia ; *Cellular Microenvironment/drug effects/physiology ; *Drug Resistance, Fungal ; Oxygen/pharmacology ; }, abstract = {Human fungal infections may fail to respond to contemporary antifungal therapies in vivo despite in vitro fungal isolate drug susceptibility. Such a discrepancy between in vitro antimicrobial susceptibility and in vivo treatment outcomes is partially explained by microbes adopting a drug-resistant biofilm mode of growth during infection. The filamentous fungal pathogen Aspergillus fumigatus forms biofilms in vivo, and during biofilm growth it has reduced susceptibility to all three classes of contemporary antifungal drugs. Specific features of filamentous fungal biofilms that drive antifungal drug resistance remain largely unknown. In this study, we applied a fluorescence microscopy approach coupled with transcriptional bioreporters to define spatial and temporal oxygen gradients and single-cell metabolic activity within A. fumigatus biofilms. Oxygen gradients inevitably arise during A. fumigatus biofilm maturation and are both critical for, and the result of, A. fumigatus late-stage biofilm architecture. We observe that these self-induced hypoxic microenvironments not only contribute to filamentous fungal biofilm maturation but also drive resistance to antifungal treatment. Decreasing oxygen levels toward the base of A. fumigatus biofilms increases antifungal drug resistance. Our results define a previously unknown mechanistic link between filamentous fungal biofilm physiology and contemporary antifungal drug resistance. Moreover, we demonstrate that drug resistance mediated by dynamic oxygen gradients, found in many bacterial biofilms, also extends to the fungal kingdom. The conservation of hypoxic drug-resistant niches in bacterial and fungal biofilms is thus a promising target for improving antimicrobial therapy efficacy.}, } @article {pmid32847685, year = {2020}, author = {Tao, S and Su, Z and Xiang, Z and Xu, HHK and Weir, MD and Fan, M and Yu, Z and Zhou, X and Liang, K and Li, J}, title = {Nano-calcium phosphate and dimethylaminohexadecyl methacrylate adhesive for dentin remineralization in a biofilm-challenged environment.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {10}, pages = {e316-e328}, doi = {10.1016/j.dental.2020.08.001}, pmid = {32847685}, issn = {1879-0097}, mesh = {Anti-Bacterial Agents ; Biofilms ; Calcium Phosphates/pharmacology ; *Dental Cements ; Dentin ; Environment ; Humans ; *Methacrylates ; }, abstract = {OBJECTIVE: Dentin remineralization at the bonded interface would protect it from external risk factors, therefore, would enhance the longevity of restoration and combat secondary caries. Dental biofilm, as one of the critical biological factors in caries formation, should not be neglected in the assessment of caries preventive agents. In this work, the remineralization effectiveness of demineralized human dentin in a multi-species dental biofilm environment via an adhesive containing nanoparticles of amorphous calcium phosphate (NACP) and dimethylaminohexadecyl methacrylate (DMAHDM) was investigated.

METHODS: Dentin demineralization was promoted by subjecting samples to a three-species acidic biofilm containing Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii for 24h. Samples were divided into a control group, a DMAHDM adhesive group, an NACP group, and an NACP+DMAHDM adhesive group. A bonded model containing a control-bonded group, a DMAHDM-bonded group, an NACP-bonded group, and an NACP+DMAHDM-bonded group was also included in this study. All samples were subjected to a remineralization protocol consisting of 4-h exposure per 24-h period in brain heart infusion broth plus 1% sucrose (BHIS) followed by immersion in artificial saliva for the remaining period. The pH of BHIS after 4-h immersion was measured every other day. After 14 days, the biofilm was assessed for colony-forming unit (CFU) count, lactic acid production, live/dead staining, and calcium and phosphate content. The mineral changes in the demineralized dentin samples were analyzed by transverse microradiography.

RESULTS: The in vitro experiment results showed that the NACP+DMAHDM adhesive effectively achieved acid neutralization, decreased biofilm colony-forming unit (CFU) count, decreased biofilm lactic acid production, and increased biofilm calcium and phosphate content. The NACP+DMAHDM adhesive group had higher remineralization value than the NACP or DMAHDM alone adhesive group.

SIGNIFICANCE: The NACP+DMAHDM adhesive was effective in remineralizing dentin lesion in a biofilm model. It is promising to use NACP+DMAHDM adhesive to protect bonded interface, inhibit secondary caries, and prolong the longevity of restoration.}, } @article {pmid32847138, year = {2020}, author = {Sabbatini, S and Monari, C and Ballet, N and Decherf, AC and Bozza, S and Camilloni, B and Perito, S and Vecchiarelli, A}, title = {Anti-Biofilm Properties of Saccharomyces cerevisiae CNCM I-3856 and Lacticaseibacillus rhamnosus ATCC 53103 Probiotics against G. vaginalis.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32847138}, issn = {2076-2607}, support = {C3928-01//Lesaffre International/ ; }, abstract = {Bacterial vaginosis (BV) is characterized by the presence of a polymicrobial biofilm where Gardnerella vaginalis plays a key role. Previously, we demonstrated that Saccharomyces cerevisiae CNCM (French National Collection of Cultures of Microorganisms) I-3856 is helpful in resolving experimental simulated BV in mice. In this study, we analyzed its capacity to affect G. vaginalis biofilms and to potentiate the activity of standard antimicrobial agents. We also investigated the anti-biofilm activity of Lacticaseibacillus rhamnosus GG (ATCC 53103), a well-known strain for its intestinal healthy benefits. Biofilm biomass was assessed by crystal violet staining, and G. vaginalis viability was assessed by a colony forming unit (CFU) assay. Here, for the first time, we demonstrated that S. cerevisiae CNCM I-3856 as well as L. rhamnosus GG were able (i) to significantly inhibit G. vaginalis biofilm formation, (ii) to markedly reduce G. vaginalis viability among the biomass constituting the biofilm, (iii) to induce disaggregation of preformed biofilm, and (iv) to kill a consistent amount of bacterial cells in a G. vaginalis preformed biofilm. Furthermore, S. cerevisiae CNCM I-3856 strongly potentiates the metronidazole effect on G. vaginalis biofilm viability. These results suggest that S. cerevisiae CNCM I-3856 as well as L. rhamnosus GG could be potential novel therapeutic agents against bacterial vaginosis.}, } @article {pmid32846942, year = {2020}, author = {Bose, R and Ioannidis, K and Foschi, F and Bakhsh, A and Kelly, RD and Deb, S and Mannocci, F and Niazi, SA}, title = {Antimicrobial Effectiveness of Calcium Silicate Sealers against a Nutrient-Stressed Multispecies Biofilm.}, journal = {Journal of clinical medicine}, volume = {9}, number = {9}, pages = {}, pmid = {32846942}, issn = {2077-0383}, abstract = {PURPOSE: This study compared the antimicrobial efficacy of calcium silicate sealers (BioRoot RCS and Total Fill BC) and conventional sealers (AH Plus and Tubli-seal) against planktonic bacteria and a nutrient-stressed multispecies biofilm.

METHODS: Antimicrobial properties of freshly mixed sealers were investigated using the direct contact test (DCT) and a nutrient-stressed multispecies biofilm comprised of five endodontic strains. Antimicrobial activity was determined using quantitative viable counts and confocal laser scanning microscopy (CLSM) analysis with live/dead staining. The pH of the sealers was analysed over a period of 28 days in Hanks Balanced Salt Solution (HBSS). Analysis of variance (ANOVA) with Tukey tests and the Kruskal-Wallis test were used for data analysis with a significance of 5%.

RESULTS: All endodontic sealers exhibited significant antimicrobial activity against planktonic bacteria (p < 0.05). BioRoot RCS caused a significant reduction in viable counts of the biofilms compared to AH Plus and the control (p < 0.05), while no significant difference could be observed compared to TotalFill BC and Tubli-seal (p > 0.05). CLSM analysis showed that BioRoot RCS and TotalFill BC exhibited significant biofilm inhibition compared to Tubli-seal, AH Plus and the control (p < 0.05). BioRoot RCS presented with the highest microbial killing, followed by TotalFill BC and Tubli-seal. Alkalizing activity was seen from the onset by BioRoot RCS, TotalFill BC and AH Plus. After 28 days, BioRoot RCS demonstrated the highest pH in HBSS (pH > 12).

CONCLUSIONS: Calcium silicate sealers exhibited effective antimicrobial properties. This was demonstrated by superior biofilm inhibition capacity and microbial killing, with strong alkalizing activity compared to epoxy-based and zinc oxide-eugenol-based sealers.}, } @article {pmid32846586, year = {2020}, author = {Fernández-Gómez, P and López, M and Prieto, M and González-Raurich, M and Alvarez-Ordóñez, A}, title = {The role of the general stress response regulator RpoS in Cronobacter sakazakii biofilm formation.}, journal = {Food research international (Ottawa, Ont.)}, volume = {136}, number = {}, pages = {109508}, doi = {10.1016/j.foodres.2020.109508}, pmid = {32846586}, issn = {1873-7145}, mesh = {Biofilms ; *Cronobacter sakazakii/genetics ; Culture Media ; Microscopy, Electron, Scanning ; Stainless Steel ; }, abstract = {The relationship between biofilm formation and RpoS status was assessed in nine field isolates of C. sakazakii. Their ability to form biofilms was studied in BHI and minimum media with different pH values and supplemented or not with the amino acids arginine, lysine and glutamic acid. Biofilm formation, both on polystyrene and stainless steel, was measured by spectrometric determination of the fixed crystal violet and the biofilms were visualized by confocal laser scanning microscopy and scanning electron microscopy. Despite the existing heterogeneity among the different strains, biofilm formation was generally higher in buffered minimum media (pH 7.0) supplemented with lysine than in other culture media and on stainless steel plates than on polystyrene. The results showed a lower ability to form biofilms for a strain with a loss-of-function mutation in the rpoS gene, the general stress response regulator of Gram-negative bacteria, when compared to the rest of the strains, which harboured a functional rpoS. The complementation of this strain with a functional rpoS gene resulted in an increase in its biofilm formation ability up to levels comparable to those observed for strains with a functional rpoS. However, the differences were markedly reduced when the incubation time was increased from 24 to 48 h, indicating that the loss of RpoS caused a delay in the development of mature biofilms, rather than a complete inhibition of biofilm production in C. sakazakii.}, } @article {pmid32844569, year = {2021}, author = {Walsh, DJ and Livinghouse, T and Durling, GM and Arnold, AD and Brasier, W and Berry, L and Goeres, DM and Stewart, PS}, title = {Novel phenolic antimicrobials enhanced activity of iminodiacetate prodrugs against biofilm and planktonic bacteria.}, journal = {Chemical biology & drug design}, volume = {97}, number = {1}, pages = {134-147}, pmid = {32844569}, issn = {1747-0285}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Imino Acids/*chemistry ; Microbial Sensitivity Tests ; Phenols/*chemistry/pharmacology ; Prodrugs/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/physiology ; Staphylococcus epidermidis/drug effects/physiology ; Structure-Activity Relationship ; }, abstract = {Prodrugs are pharmacologically attenuated derivatives of drugs that undergo bioconversion into the active compound once reaching the targeted site, thereby maximizing their efficiency. This strategy has been implemented in pharmaceuticals to overcome obstacles related to absorption, distribution, and metabolism, as well as with intracellular dyes to ensure concentration within cells. In this study, we provide the first examples of a prodrug strategy that can be applied to simple phenolic antimicrobials to increase their potency against mature biofilms. The addition of (acetoxy)methyl iminodiacetate groups increases the otherwise modest potency of simple phenols. Biofilm-forming bacteria exhibit a heightened tolerance toward antimicrobial agents, thereby accentuating the need for new antibiotics as well as those, which incorporate novel delivery strategies to enhance activity toward biofilms.}, } @article {pmid32843653, year = {2020}, author = {Kho, W and Kim, MK and Jung, M and Chong, YP and Kim, YS and Park, KH and Chong, Y}, title = {Strain-specific anti-biofilm and antibiotic-potentiating activity of 3',4'-difluoroquercetin.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {14162}, pmid = {32843653}, issn = {2045-2322}, mesh = {Animals ; Animals, Outbred Strains ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/classification/*drug effects ; Ceftazidime/pharmacology ; Drug Evaluation, Preclinical ; Drug Synergism ; Female ; Gram-Negative Bacteria/drug effects ; Membrane Transport Proteins/drug effects ; Mice ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas Infections/drug therapy ; Quercetin/chemistry ; Random Allocation ; Staphylococcus aureus/drug effects ; beta-Lactam Resistance/drug effects ; }, abstract = {Antibacterial properties of 3',4'-difluoroquercetin (di-F-Q), a fluorine-substituted stable quercetin derivative, were investigated. Even though di-F-Q itself did not show interesting antibacterial activity, treatment of the Staphylococcus aureus strains with di-F-Q resulted in a dose-dependent reduction in biofilm formation with IC50 values of 1.8 ~ 5.3 mg/L. Also, the antibacterial activity of ceftazidime (CAZ) against carbapenem-resistant Pseudomonas aeruginosa (CRPA) showed eightfold decrease upon combination with di-F-Q. Assessment of the antimicrobial activity of CAZ in combination with di-F-Q against 50 clinical isolates of P. aeruginosa confirmed 15.7% increase in the percentages of susceptible P. aeruginosa isolates upon addition of di-F-Q to CAZ. Further mechanistic studies revealed that di-F-Q affected the antibiotics efflux system in CRPA but not the β-lactamase activity. Thus, di-F-Q was almost equally effective as carbonyl cyanide m-chlorophenyl hydrazine in inhibiting antibiotic efflux by P. aeruginosa. In vivo evaluation of the therapeutic efficacy of CAZ-(di-F-Q) combination against P. aeruginosa showed 20% of the mice treated with CAZ-(di-F-Q) survived after 7 days in IMP carbapenemase-producing multidrug-resistant P. aeruginosa infection group while no mice treated with CAZ alone survived after 2 days. Taken together, di-F-Q demonstrated unique strain-specific antimicrobial properties including anti-biofilm and antibiotic-potentiating activity against S. aureus and P. aeruginosa, respectively.}, } @article {pmid32841855, year = {2020}, author = {Cook, S and Price, O and King, A and Finnegan, C and van Egmond, R and Schäfer, H and Pearson, JM and Abolfathi, S and Bending, GD}, title = {Bedform characteristics and biofilm community development interact to modify hyporheic exchange.}, journal = {The Science of the total environment}, volume = {749}, number = {}, pages = {141397}, doi = {10.1016/j.scitotenv.2020.141397}, pmid = {32841855}, issn = {1879-1026}, mesh = {Biofilms ; Geologic Sediments ; Hydrology ; *Microbiota ; *Rivers ; }, abstract = {The physical and biological attributes of riverine ecosystems interact in a complex manner which can affect the hydrodynamic behaviour of the system. This can alter the mixing characteristics of a river at the sediment-water interface. Research on hyporheic exchange has increased in recent years driven by a greater appreciation for the importance of this dynamic ecotone in connecting and regulating river systems. An understanding of process-based interactions driving hyporheic exchange is still limited, specifically the feedbacks between the physical and biological controlling factors. The interplay between bed morphology and sediment size on biofilm community development and the impact on hyporheic exchange mechanisms, was experimentally considered. Purpose built recirculating flume systems were constructed and three profiles of bedform investigated: i) flat, ii) undulating λ = 1 m, ii) undulating λ = 0.2 m, across two different sized sediments (0.5 mm and 5 mm). The influence of biofilm growth and bedform interaction on hyporheic exchange was explored, over time, using discrete repeat injections of fluorescent dye into the flumes. Hyporheic exchange rates were greatest in systems with larger sediment sizes (5 mm) and with more bedforms (undulating λ = 0.2). Sediment size was a dominant control in governing biofilm growth and hyporheic exchange in systems with limited bedform. In systems where bedform was prevalent, sediment size and biofilm appeared to no longer be a control on exchange due to the physical influence of advective pumping. Here, exchange rates within these environments were more consistent overtime, despite greater microbial growth. As such, bedform has the potential to overcome the rate limiting effects of biotic factors on hyporheic exchange and sediment size on microbial penetration. This has implications for pollutant and nutrient penetration; bedforms increase hydrological connectivity, generating the opportunity to support microbial communities at depth and as such, improve the self-purification ability of river systems.}, } @article {pmid32841296, year = {2020}, author = {Schwechheimer, C and Hebert, K and Tripathi, S and Singh, PK and Floyd, KA and Brown, ER and Porcella, ME and Osorio, J and Kiblen, JTM and Pagliai, FA and Drescher, K and Rubin, SM and Yildiz, FH}, title = {A tyrosine phosphoregulatory system controls exopolysaccharide biosynthesis and biofilm formation in Vibrio cholerae.}, journal = {PLoS pathogens}, volume = {16}, number = {8}, pages = {e1008745}, pmid = {32841296}, issn = {1553-7374}, support = {R01 AI055987/AI/NIAID NIH HHS/United States ; R01 AI114261/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Phosphorylation/physiology ; Polysaccharides, Bacterial/*biosynthesis/genetics ; *Protein Multimerization ; Protein Tyrosine Phosphatases/genetics/*metabolism ; Vibrio cholerae/*physiology ; }, abstract = {Production of an extracellular matrix is essential for biofilm formation, as this matrix both secures and protects the cells it encases. Mechanisms underlying production and assembly of matrices are poorly understood. Vibrio cholerae, relies heavily on biofilm formation for survival, infectivity, and transmission. Biofilm formation requires Vibrio polysaccharide (VPS), which is produced by vps gene-products, yet the function of these products remains unknown. Here, we demonstrate that the vps gene-products vpsO and vpsU encode respectively for a tyrosine kinase and a cognate tyrosine phosphatase. Collectively, VpsO and VpsU act as a tyrosine phosphoregulatory system to modulate VPS production. We present structures of VpsU and the kinase domain of VpsO, and we report observed autocatalytic tyrosine phosphorylation of the VpsO C-terminal tail. The position and amount of tyrosine phosphorylation in the VpsO C-terminal tail represses VPS production and biofilm formation through a mechanism involving the modulation of VpsO oligomerization. We found that tyrosine phosphorylation enhances stability of VpsO. Regulation of VpsO phosphorylation by the phosphatase VpsU is vital for maintaining native VPS levels. This study provides new insights into the mechanism and regulation of VPS production and establishes general principles of biofilm matrix production and its inhibition.}, } @article {pmid32840477, year = {2020}, author = {Askora, A and El-Telbany, M and El-Didamony, G and Ariny, E and Askoura, M}, title = {Characterization of φEf-vB1 prophage infecting oral Enterococcus faecalis and enhancing bacterial biofilm formation.}, journal = {Journal of medical microbiology}, volume = {69}, number = {9}, pages = {1151-1168}, doi = {10.1099/jmm.0.001246}, pmid = {32840477}, issn = {1473-5644}, mesh = {Bacteriophages/*physiology ; Base Composition ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis/genetics/isolation & purification/*physiology/*virology ; Genome, Viral ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Lysogeny ; Open Reading Frames ; Periodontitis ; Prophages/classification/genetics/isolation & purification/*physiology ; Siphoviridae/classification/genetics/*isolation & purification/physiology ; }, abstract = {Introduction. Enterococcus faecalis is a facultative, anaerobic, opportunistic pathogen associated with medical and dental diseases. Bacterial phenotypic traits and pathogenesis are often influenced by lysogeny.Aim. The aim of this study was to characterize both the morphology and complete genome sequences of induced prophages purified from E. faecalis clinical isolates.Methodology. E. faecalis isolates were recovered from the roots of teeth of patients attending an endodontic clinic. The morphological features of isolated phage were characterized using transmission electron microscopy (TEM). DNA sequencing was performed using the Illumina MiSeq platform.Results. TEM indicated that the isolated φEf-vB1 prophage belongs to the family Siphoviridae. The φEf-vB1 prophage was stable over a wide range of temperatures and pH. Sequencing of φEf-vB1 DNA revealed that the phage genome is 37 561 bp in length with a G+C content of 37.6mol% and contained 53 ORFs. Comparison with previously predicted prophage genomes using blast revealed that φEf-vB1 has a high sequence similarity to previously characterized phage genomes. The lysogenic E. faecalis strain exhibited a higher biofilm formation capacity relative to the non-lysogenic strain.Conclusion. The current findings highlight the role of lysogeny in modification of E. faecalis properties and reveal the potential importance of prophages in E. faecalis biology and pathogenesis.}, } @article {pmid32840353, year = {2020}, author = {Haidari, H and Kopecki, Z and Bright, R and Cowin, AJ and Garg, S and Goswami, N and Vasilev, K}, title = {Ultrasmall AgNP-Impregnated Biocompatible Hydrogel with Highly Effective Biofilm Elimination Properties.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {37}, pages = {41011-41025}, doi = {10.1021/acsami.0c09414}, pmid = {32840353}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biocompatible Materials/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Escherichia coli/drug effects ; Fibroblasts/drug effects ; Humans ; Hydrogels/chemical synthesis/chemistry/*pharmacology ; Keratinocytes/drug effects ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Particle Size ; Pseudomonas aeruginosa/drug effects ; Silver/chemistry/*pharmacology ; Staphylococcus aureus/drug effects ; Staphylococcus epidermidis/drug effects ; Surface Properties ; Thiomalates/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Ultrasmall silver nanoparticles (AgNPs; size < 3 nm) have attracted a great deal of interest as an alternative to commercially available antibiotics due to their ability to eliminate a wide range of microbial pathogens. However, most of these ultrasmall AgNPs are highly reactive and unstable, as well as susceptible to fast oxidation. Therefore, both the stability and toxicity remain major shortcomings for their clinical application and uptake. To circumvent these problems, we present a novel strategy to impregnate ultrasmall AgNPs into a biocompatible thermosensitive hydrogel that enables controlled release of silver alongside long-term storage stability and highly potent antibacterial activity. The advantage of this strategy lies in the combination of a homogenous dispersion of AgNPs in a hydrogel network, which serves as a sustained-release reservoir, and the unique feature of ultrasmall AgNP size, which provides an improved biofilm eradication capacity. The superior biofilm dispersion properties of the AgNP hydrogel is demonstrated in both single-species and multispecies biofilms, eradicating ∼80% of established biofilms compared to untreated controls. Notably, the effective antibacterial concentration of the formulation shows minimal toxicity to human fibroblasts and keratinocytes. These findings present a promising novel strategy for the development of AgNP hydrogels as an efficient antibacterial platform to combat resistant bacterial biofilms associated with wound infections.}, } @article {pmid32840051, year = {2020}, author = {Abdel Razek, MMM and Moussa, AY and El-Shanawany, MA and Singab, ANB}, title = {A New Phenolic Alkaloid from Halocnemum strobilaceum Endophytes: Antimicrobial, Antioxidant and Biofilm Inhibitory Activities.}, journal = {Chemistry & biodiversity}, volume = {17}, number = {10}, pages = {e2000496}, doi = {10.1002/cbdv.202000496}, pmid = {32840051}, issn = {1612-1880}, support = {//NMR facility/ ; //ESI-LC/MS/ ; //Center for Drug Discovery and Research Development/ ; }, mesh = {Alkaloids/chemistry/isolation & purification/*pharmacology ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Antioxidants/chemistry/isolation & purification/*pharmacology ; Biofilms/drug effects ; Cell Line, Tumor ; Chenopodiaceae/chemistry ; Endophytes/*chemistry ; Fluorescence Recovery After Photobleaching ; Humans ; Molecular Conformation ; Oxidative Stress/drug effects ; Penicillium/chemistry ; Phenols/chemistry/isolation & purification/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Reactive Oxygen Species/metabolism ; }, abstract = {Human infections caused by microbial biofilm formation represent a growing major health threat. A new alkaloid, 3-amino-5-(3-hydroxybutan-2-yl)-4-methylphenol, was isolated from the corn grit culture of the endophytic isolate Penicillium citrinum-314 associated with Halocnemum strobilaceum, a halophyte growing in the Egyptian marshes. The new alkaloid was identified by 1D, 2D-NMR and HR-ESI-MS-MS and given the trivial name halociline. The antioxidant, antimicrobial and antibiofilm activities were recorded. Furthermore, another known compound, 1,3,6-trihydroxy-7-methoxy-9H-xanthen-9-one, was obtained in smaller amounts and revealed a non-microbicidal 100 % reduction in biofilm formation, with an MBIC value of 62.5 μg/mL (228 μM) against Pseudomonas aeruginosa (Ferm-BAM), a FRAP value of 447.941±37.876 mM/L as well as a marked safety profile against three cancer cell lines. Through in silico molecular docking study, in the binding sites of Pseudomonas enzymes, key ligand enzyme interactions were determined to support the in vitro results.}, } @article {pmid32839480, year = {2020}, author = {Qayoom, I and Verma, R and Murugan, PA and Raina, DB and Teotia, AK and Matheshwaran, S and Nair, NN and Tägil, M and Lidgren, L and Kumar, A}, title = {A biphasic nanohydroxyapatite/calcium sulphate carrier containing Rifampicin and Isoniazid for local delivery gives sustained and effective antibiotic release and prevents biofilm formation.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {14128}, pmid = {32839480}, issn = {2045-2322}, mesh = {Antitubercular Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Bone Regeneration/drug effects ; Calcium Sulfate/*pharmacology ; Computational Biology ; Delayed-Action Preparations/pharmacology ; Drug Carriers/*pharmacology ; Drug Interactions ; Drug Therapy, Combination ; Durapatite/*pharmacology ; Isoniazid/*pharmacology ; Microbial Sensitivity Tests ; Mycobacterium smegmatis/drug effects ; Rifampin/*pharmacology ; Tuberculosis, Osteoarticular/*drug therapy ; }, abstract = {Long term multiple systemic antibiotics form the cornerstone in the treatment of bone and joint tuberculosis, often combined with local surgical eradication. Implanted carriers for local drug delivery have recently been introduced to overcome some of the limitations associated with conventional treatment strategies. In this study, we used a calcium sulphate hemihydrate (CSH)/nanohydroxyapatite (nHAP) based nanocement (NC) biomaterial as a void filler as well as a local delivery carrier of two standard of care tuberculosis drugs, Rifampicin (RFP) and Isoniazid (INH). We observed that the antibiotics showed different release patterns where INH showed a burst release of 67% and 100% release alone and in combination within one week, respectively whereas RFP showed sustained release of 42% and 49% release alone and in combination over a period of 12 weeks, respectively indicating different possible interactions of antibiotics with nHAP. The interactions were studied using computational methodology, which showed that the binding energy of nHAP with RFP was 148 kcal/mol and INH was 11 kcal/mol, thus varying substantially resulting in RFP being retained in the nHAP matrix. Our findings suggest that a biphasic ceramic based drug delivery system could be a promising treatment alternative to bone and joint TB.}, } @article {pmid32839186, year = {2020}, author = {Zafar, M and Jahan, H and Shafeeq, S and Nimtz, M and Jänsch, L and Römling, U and Choudhary, MI}, title = {Clarithromycin Exerts an Antibiofilm Effect against Salmonella enterica Serovar Typhimurium rdar Biofilm Formation and Transforms the Physiology towards an Apparent Oxygen-Depleted Energy and Carbon Metabolism.}, journal = {Infection and immunity}, volume = {88}, number = {11}, pages = {}, pmid = {32839186}, issn = {1098-5522}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Clarithromycin/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Salmonella typhimurium/*drug effects/*physiology ; }, abstract = {Upon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection toward various forms of environmental stresses to individual cells. Thus, bacterial cells within biofilms become tolerant against antimicrobials and the immune system. In the present study, we evaluated the antibiofilm activity of the macrolides clarithromycin and azithromycin. Clarithromycin showed antibiofilm activity against rdar (red, dry, and rough) biofilm formation of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium ATCC 14028 (Nal[r]) at a 1.56 μM subinhibitory concentration in standing culture and dissolved cell aggregates at 15 μM in a microaerophilic environment, suggesting that the oxygen level affects the activity of the drug. Treatment with clarithromycin significantly decreased transcription and production of the rdar biofilm activator CsgD, with biofilm genes such as csgB and adrA to be concomitantly downregulated. Although fliA and other flagellar regulon genes were upregulated, apparent motility was downregulated. RNA sequencing showed a holistic cell response upon clarithromycin exposure, whereby not only genes involved in the biofilm-related regulatory pathways but also genes that likely contribute to intrinsic antimicrobial resistance, and the heat shock stress response were differentially regulated. Most significantly, clarithromycin exposure shifted the cells toward an apparent oxygen- and energy-depleted status, whereby the metabolism that channels into oxidative phosphorylation was downregulated, and energy gain by degradation of propane 1,2-diol, ethanolamine and l-arginine catabolism, potentially also to prevent cytosolic acidification, was upregulated. This analysis will allow the subsequent identification of novel intrinsic antimicrobial resistance determinants.}, } @article {pmid32838699, year = {2022}, author = {Mansuri, A and Lokhande, K and Kore, S and Gaikwad, S and Nawani, N and Swamy, KV and Junnarkar, M and Pawar, S}, title = {Antioxidant, anti-quorum sensing, biofilm inhibitory activities and chemical composition of Patchouli essential oil: in vitro and in silico approach.}, journal = {Journal of biomolecular structure & dynamics}, volume = {40}, number = {1}, pages = {154-165}, doi = {10.1080/07391102.2020.1810124}, pmid = {32838699}, issn = {1538-0254}, mesh = {Anti-Bacterial Agents/pharmacology ; Antioxidants/pharmacology ; Biofilms ; Molecular Docking Simulation ; *Oils, Volatile/pharmacology ; Plant Extracts/pharmacology ; *Pogostemon ; Quorum Sensing ; Virulence Factors ; }, abstract = {The interest in naturally occurring essential oils from medicinal plants has increased extremely over the last decade markedly because they possess antimicrobial and antioxidant protective properties against different chronic diseases. Extensive survival of drug-resistant infectious bacteria depends on quorum sensing (QS) signaling network which raises the need for alternative antibacterial compounds. The aim of this study was to examine the phytochemical compounds of patchouli essential oil (PEO) and to assess its antioxidant activity. Antioxidant studies estimated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method showed that the PEO has effective antioxidant activity (IC50 19.53 µg/mL). QS inhibitory activity of PEO was examined by employing the biosensor strain, Chromobacterium violaceum CV12472. At sub-lethal concentrations, PEO potentially reduced the QS regulated violacein synthesis in CV12472 without inhibiting its cell proliferation. Moreover, it also effectively reduced the production of some QS regulated virulence factors and biofilm development in P. aeruginosa PAO1 without hindering its growth. Phytochemical analysis of PEO was done by GC/MS technique. Molecular docking of PEO major compounds with QS (LasR and FabI) and biofilm regulator proteins (MvfR and Sialidase) of PAO1 was evaluated. These phytocompounds showed potential hydrogen binding interactions with these proteins. The overall results, in vitro and in silico, suggest that PEO could be applied as biocontrol agent against antibiotic resistance pathogens. Communicated by Ramaswamy H. Sarma.}, } @article {pmid32838409, year = {2020}, author = {Brilhante, RSN and Costa, ADC and Pereira, VS and Fernandes, MR and de Oliveira, JS and Rodrigues, AM and Camargo, ZP and Pereira-Neto, WA and Sidrim, JJC and Rocha, MFG}, title = {Antifungal activity of deferiprone and EDTA against Sporothrix spp.: Effect on planktonic growth and biofilm formation.}, journal = {Medical mycology}, volume = {}, number = {}, pages = {}, doi = {10.1093/mmy/myaa073}, pmid = {32838409}, issn = {1460-2709}, abstract = {UNLABELLED: The present study evaluated the antifungal activity of the chelators deferiprone (DFP) and ethylenediaminetetraacetic acid (EDTA) and their effect on biofilm formation of the S. schenckii complex. Eighteen strains of Sporothrix spp. (seven S. brasiliensis, three S. globosa, three S. mexicana and five Sporothrix schenckii sensu stricto) were used. Minimum inhibitory concentration (MIC) values for EDTA and DFP against filamentous forms of Sporothrix spp. ranged from 32 to 128 μg/ml. For antifungal drugs, MIC values ranged from 0.25 to 4 μg/ml for amphotericin B, from 0.25 to 4 μg/ml for itraconazole, and from 0.03 to 0.25 μg/ml for terbinafine. The chelators caused inhibition of Sporothrix spp. in yeast form at concentrations ranging from 16 to 64 μg/ml (for EDTA) and 8 to 32 μg/ml (for DFP). For antifungal drugs, MIC values observed against the yeast varied from 0.03 to 0.5 μg/ml for AMB, 0.03 to 1 μg/ml for ITC, and 0.03 to 0.13 μg/ml for TRB. Both DFP and EDTA presented synergistic interaction with antifungals against Sporothrix spp. in both filamentous and yeast form. Biofilms formed in the presence of the chelators (512 μg/ml) showed a reduction of 47% in biomass and 45% in metabolic activity. Our data reveal that DFP and EDTA reduced the growth of planktonic cells of Sporothrix spp., had synergistic interaction with antifungal drugs against this pathogen, and reduced biofilm formation of Sporothrix spp.

LAY SUMMARY: Our data reveal that iron chelators deferiprone and ethylenediaminetetraacetic acid reduced the growth of planktonic cells of Sporothrix spp. as well as had synergistic interaction with antifungal drugs against this pathogen and reduced biofilm formation of Sporothrix spp.}, } @article {pmid32835773, year = {2020}, author = {Lima, SL and Rossato, L and Salles de Azevedo Melo, A}, title = {Evaluation of the potential virulence of Candida haemulonii species complex and Candida auris isolates in Caenorhabditis elegans as an in vivo model and correlation to their biofilm production capacity.}, journal = {Microbial pathogenesis}, volume = {148}, number = {}, pages = {104461}, doi = {10.1016/j.micpath.2020.104461}, pmid = {32835773}, issn = {1096-1208}, mesh = {Animals ; Antifungal Agents/pharmacology ; Biofilms ; Caenorhabditis elegans ; *Candida ; *Candidiasis ; Virulence ; }, abstract = {Candida haemulonii species complex (Can. haemulonii sensu stricto, Can. duobushaemulonii and Can. haemulonii var. vulnera) and related species (Can. auris and Can. pseudohaemulonii) have attracted attention due to reduced susceptibility to azoles and amphotericin B. Furthermore, attributes of potential virulence have been recognized in Can. haemulonii species complex and Can. auris, like the capability to form biofilm, which represent the most important risk factors for persistent candidemia. However, the relationship between biofilm production and impact on host mortality is still unclear. To evaluate the potential virulence of Can. haemulonii species complex and Can. auris isolates by correlating biofilm production and capacity to kill Caenorhabditis elegans as an in vivo model. In this study, virulence factors were characterized among a total of sixty-six Can. haemulonii species complex and Can. auris isolates to gain insight about virulence traits of these pathogenic yeasts by evaluating the in vitro biofilm production and potential pathogenicity for Cae. elegans, as an in vivo infection model. All clinical isolates tested were biofilm producer, inter- and intra-specific differences on the biofilm forming capacity by the strains were observed. Can. auris and Can. haemuolonii var. vulnera showed similar biofilm production, both higher than Can. haemulonii sensu stricto and Can. duobushaemulonii. Regarding the virulence of the Cae. elegans model, Can. haemulonii species complex and Can. auris isolates were capable of causing infection in Cae. elegans, and our data suggest that the high biofilm production by Can. haemulonii var. vulnera and Can. duobushaemulonii isolates may impact in the pathogenicity caused on Cae. elegans.}, } @article {pmid32835683, year = {2020}, author = {Zhou, Y and Li, R and Guo, B and Zhang, L and Zhang, H and Xia, S and Liu, Y}, title = {Three-dimension oxygen gradient induced low energy input for grey water treatment in an oxygen-based membrane biofilm reactor.}, journal = {Environmental research}, volume = {191}, number = {}, pages = {110124}, doi = {10.1016/j.envres.2020.110124}, pmid = {32835683}, issn = {1096-0953}, mesh = {Biofilms ; Bioreactors ; Humans ; Nitrogen ; *Oxygen ; Waste Disposal, Fluid ; Wastewater ; *Water Purification ; }, abstract = {Grey water (GW) containing high levels of linear alkylbenzene sulfonates (LAS) can be a threat to human health and organisms in the environment if not treated properly. Although aerobic treatment could achieve high organics removal efficiency, conventional aeration can lead to serious foaming and energy waste. Here, we systematically evaluated an oxygen based membrane biofilm reactor (O2-MBfR) for its capacity to simultaneously remove organics and nitrogen from GW. The dissolved oxygen (DO) concentration inside the reactor was maintained at 0.4 mg/L by gradually controlling the lumen air pressure. Results showed that the O2-MBfR achieved high removal efficiency of total chemical oxygen demand (TCOD), total linear alkylbenzene sulfonates (LAS) and total nitrogen (TN) of 89.7%, 99.1% and 78.1%, respectively, with a hydraulic retention time (HRT) of 7.5 h. Lower HRT (7.0 h) led to the accumulation of LAS in the biofilm, which caused cell lysis and damaged the O2-MBfR system, leading to a discernible and continuous decline of the reactor performance. The O2-MBfR design completely eliminated foaming formation and the three-dimension oxygen gradient design led to low air pressure inside the membrane fiber, which enabled the high removal efficiency for both organics and nitrogen with low energy input and GW treatment cost, providing the fundamental knowledge for practical application of O2-MBfR in wastewater treatment.}, } @article {pmid32835161, year = {2020}, author = {Khuntia, HK and Chanakya, HN}, title = {Accumulation of antibiotic-resistant genes in anaerobic biofilm reactor fed with household chemical products.}, journal = {SN applied sciences}, volume = {2}, number = {8}, pages = {1320}, pmid = {32835161}, issn = {2523-3971}, abstract = {This research aims to determine the presence of antibiotic-resistant genes (ARG) in anaerobic biofilm reactors (ABR) fed with household chemical products (HCP) such as laundry detergents and handwash without any influx of antibiotics. The ABR comprised a three-chamber design with bottom sludge, a middle chamber containing fluidized PVC spiral, and a top chamber with packed coir fiber as a biofilm support medium, respectively. Four different ABRs were simultaneously operated for a prolonged period (200 day) and subjected to variations in physicochemical conditions. The ABRs fed with HCP exhibited solitary accumulation of log (4.4-7.5) ermC gene copies/g VS whereas, ARG was undetectable in glucose fed ABRs indicating that HCP exhibited antimicrobial activities synonyms to Erythromycin. Accumulation of Erythromycin-C (ermC) was relatively higher on the biofilm inhabiting PVC support medium and further accentuated by effluent recycling to log 7.5 ermC gene copies at a ratio of ermC/16S gene copies of 0.65. Physico-chemical factors such as substrate composition, biofilm support medium, and effluent recycling simultaneously elevated the concentration of ermC genes. The results indicated that HCP augments the accumulation of ARG in the microbiome, subsequently, increasing the risk in ARG transmission from sewage treatment plants to the ecology and humans.}, } @article {pmid32832655, year = {2020}, author = {Qu, D and Hou, Z and Li, J and Luo, L and Su, S and Ye, Z and Bai, Y and Zhang, X and Chen, G and Li, Z and Wang, Y and Xue, X and Luo, X and Li, M}, title = {A new coumarin compound DCH combats methicillin-resistant Staphylococcus aureus biofilm by targeting arginine repressor.}, journal = {Science advances}, volume = {6}, number = {30}, pages = {eaay9597}, pmid = {32832655}, issn = {2375-2548}, mesh = {Anti-Bacterial Agents/pharmacology ; Arginine/pharmacology ; Biofilms ; Coumarins ; *Methicillin-Resistant Staphylococcus aureus ; Molecular Docking Simulation ; }, abstract = {Staphylococcus aureus infection is difficult to eradicate because of biofilm formation and antibiotic resistance. The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection necessitates the development of a new agent against bacterial biofilms. We report a new coumarin compound, termed DCH, that effectively combats MRSA in vitro and in vivo and exhibits potent antibiofilm activity without detectable resistance. Cellular proteome analysis suggests that the molecular mechanism of action of DCH involves the arginine catabolic pathway. Using molecular docking and binding affinity assays of DCH, and comparison of the properties of wild-type and ArgR-deficient MRSA strains, we demonstrate that the arginine repressor ArgR, an essential regulator of the arginine catabolic pathway, is the target of DCH. These findings indicate that DCH is a promising lead compound and validate bacterial ArgR as a potential target in the development of new drugs against MRSA biofilms.}, } @article {pmid32832272, year = {2020}, author = {Ao, X and Zhao, J and Yan, J and Liu, S and Zhao, K}, title = {Comparative transcriptomic analysis of Lactiplantibacillus plantarum RS66CD biofilm in high-salt conditions and planktonic cells.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e9639}, pmid = {32832272}, issn = {2167-8359}, abstract = {BACKGROUND: Lactiplantibacillus plantarum (L. plantarum), a dominant strain in traditional fermented foods, is widely used in fermentation industry because of its fast acid production. However, L. plantarum is easily inactivated due to acidity, high temperature and other factors. The formation of biofilm by bacteria can effectively increase environmental tolerance. Therefore, it is important to improve the environmental tolerance of L. plantarum by studying its biofilm formation conditions and regulatory mechanisms.

METHODS: After determining a suitable NaCl concentration for promoting biofilm formation, L. plantarum was grown with 48 g L[-1] NaCl. Differential gene expressions in L. plantarum biofilm vs. planktonic cells were analyzed using RNA sequencing and validated using qPCR.

RESULT: L. plantarum RS66CD biofilm formation formed highest amount of when grown at 48 g L[-1] NaCl. Altogether 447 genes were up-regulated and 426 genes were down-regulated in the biofilm. KEGG pathway analysis showed that genes coding for D-Alanine metabolism, peptidoglycan biosynthesis, two-component system, carbon metabolism, bacterial secretion system, lysine biosynthesis and fatty acid metabolism were crucial for biofilm formation. In addition, eight other genes related to biofilm formation were differentially expressed. Our results provide insights into the differential gene expression involved in biofilm formation, which can help to reveal gene regulation during L. plantarum biofilm formation.}, } @article {pmid32831503, year = {2020}, author = {Resende, M and Martinez, EF}, title = {Topographic characterization and in vitro biofilm adhesion to titanium and polypropylene membranes used for alveolar preservation.}, journal = {Journal of Indian Society of Periodontology}, volume = {24}, number = {4}, pages = {316-321}, pmid = {32831503}, issn = {0972-124X}, abstract = {BACKGROUND: Nonresorbable membranes have been widely used in guided bone regeneration (GBR) procedures in posttooth extraction alveoli. In this context, one of the properties suggested by the GBR technique is that these barriers, when exposed to the oral environment, control or prevent the infiltration of connective and epithelial tissue cells, favoring the proliferation of bone cells inside the alveolus, without the growth of biofilm.

MATERIALS AND METHODS: This in vitro study evaluated the topographic characteristics and in vitro biofilm adhesion on membranes used for alveolar preservation, bone Heal™ and Titanium Seal™. Fragments of these membranes (5 mm × 5 mm) were used for all experiments. The topographical morphology and chemical characterization of the membranes were analyzed by scanning electron microscope and dispersive energy X-ray spectroscopy, respectively. For the in vitro biofilm adhesion assay, samples were immersed in Candida albicans (American Type Culture Collection [ATCC] 10231) and Staphylococcus aureus (ATCC 25923) mixed biofilm for 7 and 14 days. Biofilm formation was measured by quantitative analysis with crystal violet aqueous solution, in a spectrophotometer, with a wavelength of 590 nm.

RESULTS: The ultrastructural images showed a rough surface for the titanium membrane, without homogeneity in the surface structure, while the polypropylene membrane presented a smoother surface without depressions. The chemical composition of the membranes by Ehlers-Danlos syndrome has identified the presence of copolymer and traces of zinc for the polypropylene membrane; in contrast, the titanium membrane revealed the unique presence of titanium. In addition, there was a decrease in biofilm formation on the surface of the titanium membrane compared to polypropylene (P < 0.05), at both evaluated times.

CONCLUSIONS: It can be concluded that despite the greater heterogeneity of the titanium membrane surface, the results showed less biofilm formation on this membrane (P < 0.05), which may be indicated in cases of oral cavity exposure.}, } @article {pmid32831025, year = {2020}, author = {Chen, X and Thomsen, TR and Winkler, H and Xu, Y}, title = {Influence of biofilm growth age, media, antibiotic concentration and exposure time on Staphylococcus aureus and Pseudomonas aeruginosa biofilm removal in vitro.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {264}, pmid = {32831025}, issn = {1471-2180}, support = {27751//Det Obelske Familiefond (DK)/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Culture Media/chemistry ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/*physiology ; Staphylococcus aureus/drug effects/*physiology ; Time Factors ; Tobramycin/pharmacology ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: Biofilm is known to be tolerant towards antibiotics and difficult to eradicate. Numerous studies have reported minimum biofilm eradication concentration (MBEC) values of antibiotics for many known biofilm pathogens. However, the experimental parameters applied in these studies differ considerably, and often the rationale behind the experimental design are not well described. This makes it difficult to compare the findings. To demonstrate the importance of experimental parameters, we investigated the influence of biofilm growth age, antibiotic concentration and treatment duration, and growth media on biofilm eradication. Additionally, OSTEOmycin™, a clinically used antibiotic containing allograft bone product, was tested for antibiofilm efficacy.

RESULTS: The commonly used Calgary biofilm device was used to grow 24 h and 72 h biofilms of Staphylococcus aureus and Pseudomonas aeruginosa, which were treated with time-dependent vancomycin (up to 3000 mg L[- 1]) and concentration-dependent tobramycin (up to 80 mg L[- 1]), respectively. Two common bacteriological growth media, tryptic soy broth (TSB) and cation-adjusted Mueller Hinton broth (CaMHB), were tested. We found for both species that biofilms were more difficult to kill in TSB than in CaMHB. Furthermore, young biofilms (24 h) were easier to eradicate than old biofilms (72 h). In agreement with vancomycin being time-dependent, extension of the vancomycin exposure increased killing of S. aureus biofilms. Tobramycin treatment of 24 h P. aeruginosa biofilms was found concentration-dependent and time-independent, however, increasing killing was indicated for 72 h P. aeruginosa biofilms. Treatment with tobramycin containing OSTEOmycin T™ removed 72 h and 168 h P. aeruginosa biofilms after 1 day treatment, while few 72 h S. aureus biofilms survived after 2 days treatment with vancomycin containing OSTEOmycin V™.

CONCLUSIONS: This study demonstrated biofilm removal efficacy was influenced by media, biofilm age and antibiotic concentration and treatment duration. It is therefore necessary to taking these parameters into consideration when designing experiments. The results of OSTEOmycin™ products indicated that simple in vitro biofilm test could be used for initial screening of antibiofilm products. For clinical application, a more clinically relevant biofilm model for the specific biofilm infection in question should be developed to guide the amount of antibiotics used for local antibiofilm treatment.}, } @article {pmid32828986, year = {2020}, author = {Liu, Y and Ping, Y and Xiong, Y and Zhou, R and Xu, F and Wang, J and Li, J}, title = {Genotype, biofilm formation ability and specific gene transcripts characteristics of endodontic Enterococcus faecalis under glucose deprivation condition.}, journal = {Archives of oral biology}, volume = {118}, number = {}, pages = {104877}, doi = {10.1016/j.archoralbio.2020.104877}, pmid = {32828986}, issn = {1879-1506}, mesh = {Bacterial Proteins/genetics ; *Biofilms ; *Enterococcus faecalis/genetics/growth & development ; Genotype ; *Glucose ; }, abstract = {OBJECTIVE: To study the relationship between the specific gene and biofilm formation ability of seven wild type Enterococcus faecalis (E. faecalis) under glucose deprivation conditions.

DESIGN: Wild type E. faecalis (3RC, 5RC, 25RC, 31RC, 33RC, 37RC, 58RC) extracted from the teeth with persistent apical periodontitis were cultured under glucose deprivation conditions and then resequenced. The biofilm formation ability was compared using primary adherence assay, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The transcriptional level of biofilm formation-related genes (ace, gelE, efa, esp and fsrB) were detected.

RESULTS: Genomic resequencing showed that 3RC and 58RC (Class B) were similar, while 5RC, 25RC, 31RC, 33RC and 37RC (Class A) were similar. Based on primary adherence assay, CLSM and SEM results, biofilm formation ability of Class B strains was lower, while Class A strains were higher when compared with control group (0.25 % glucose). Furthermore, compared with control group (0.25 % glucose), the transcriptional levels of ace, efa and fsrB genes were upregulated in all strains; the transcriptional levels of gelE were downregulated in Class B strains, upregulated in Class A strains; the transcriptional levels of esp of Class B strains were downregulated, while upregulated in 25RC, 31RC and 37RC (Class A), and not observed in 5RC and 33RC.

CONCLUSION: The genotypes of wild type E. faecalis of different persistent periapical periodontitis teeth are different. The genotype differences and the transcription levels of related virulence genes (ace, gelE, efa, esp and fsrB) are related to the biological phenotype.}, } @article {pmid32828902, year = {2020}, author = {Tatta, ER and Kumavath, R}, title = {Rhodethrin and Rubrivivaxin as potential source of anti-biofilm agents against vancomycin resistant Enterococcus faecalis (ATCC 19443).}, journal = {Microbial pathogenesis}, volume = {148}, number = {}, pages = {104457}, doi = {10.1016/j.micpath.2020.104457}, pmid = {32828902}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; *Enterococcus faecalis ; Microbial Sensitivity Tests ; Vancomycin ; *Vancomycin-Resistant Enterococci ; }, abstract = {Enterococcus faecalis is frequently present in the hospital environment and readily forms a biofilm that protects from antibiotics and resistance against environmental stress conditions, thereby increasing nosocomial chronic infections. This study aims to assess antimicrobial and antibiofilm activities of two novel terpenoid derivatives Rhodethrin (Rdn) and Rubrivivaxin (Rbn) against vancomycin resistant Enterococcus faecalis strain (ATCC19443). Both terpenoids effectively prevent biofilm formation with >75% attenuation in cell biomass and significantly decrease the production of exopolysaccharides (EPSs) (p = 0.005) and besides their expansion on different surface media. The findings provide new evidence that such terpenoid derivatives could be developed as novel antibacterial drugs.}, } @article {pmid32828863, year = {2020}, author = {Ledwoch, K and Robertson, A and Lauran, J and Norville, P and Maillard, JY}, title = {It's a trap! The development of a versatile drain biofilm model and its susceptibility to disinfection.}, journal = {The Journal of hospital infection}, volume = {106}, number = {4}, pages = {757-764}, doi = {10.1016/j.jhin.2020.08.010}, pmid = {32828863}, issn = {1532-2939}, mesh = {Biofilms/*drug effects/growth & development ; Cross Infection/prevention & control ; *Disinfectants ; *Disinfection ; Hospitals ; Peracetic Acid/pharmacology ; Reproducibility of Results ; Sodium Hypochlorite/pharmacology ; Surface-Active Agents/pharmacology ; Triazines/pharmacology ; *Water Supply ; }, abstract = {BACKGROUND: Pathogens in drain biofilms pose a significant risk for hospital-acquired infection. However, the evidence of product effectiveness in controlling drain biofilm and pathogen dissemination are scarce. A novel in-vitro biofilm model was developed to address the need for a robust, reproduceable and simple testing methodology for disinfection efficacy against a complex drain biofilm.

METHODS: Identical complex drain biofilms were established simultaneously over 8 days, mimicking a sink trap. Reproducibility of their composition was confirmed by next-generation sequencing. The efficacy of sodium hypochlorite 1000 ppm (NaOCl), sodium dichloroisocyanurate 1000 ppm (NaDCC), non-ionic surfactant (NIS) and peracetic acid 4000 ppm (PAA) was explored, simulating normal sink usage conditions. Bacterial viability and recovery following a series of 15-min treatments were measured in three distinct parts of the drain.

RESULTS: The drain biofilm consisted of 119 mixed species of Gram-positive and -negative bacteria. NaOCl produced a >4 log10 reduction in viability in the drain front section alone, while PAA achieved a >4 log10 reduction in viability in all of the drain sections following three 15-min doses and prevented biofilm regrowth for >4 days. NIS and NaDCC failed to control the biofilm in any drain sections.

CONCLUSIONS: Drains are one source of microbial pathogens in healthcare settings. Microbial biofilms are notoriously difficult to eradicate with conventional chemical biocidal products. The development of this reproducible in-vitro drain biofilm model enabled understanding of the impact of biocidal products on biofilm spatial composition and viability in different parts of the drain.}, } @article {pmid32826216, year = {2020}, author = {Díaz-Garrido, N and Lozano, CP and Kreth, J and Giacaman, RA}, title = {Competition and Caries on Enamel of a Dual-Species Biofilm Model with Streptococcus mutans and Streptococcus sanguinis.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {21}, pages = {}, pmid = {32826216}, issn = {1098-5336}, support = {R01 DE021726/DE/NIDCR NIH HHS/United States ; R01 DE029492/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Dental Caries/*microbiology ; Dental Enamel/*microbiology ; *Microbial Interactions ; Streptococcus mutans/*physiology ; Streptococcus sanguis/*physiology ; }, abstract = {Imbalances within the dental biofilm trigger dental caries, currently considered a dysbiosis and the most prevalent noncommunicable disease. There is still a gap in knowledge about the dynamics of enamel colonization by bacteria from the dental biofilm in caries. The aim, therefore, was to test whether the sequence of enamel colonization by a typically commensal and a cariogenic species modifies biofilm's cariogenicity. Dual-species biofilms of Streptococcus mutans and Streptococcus sanguinis on saliva-coated enamel slabs were inoculated in different sequences: S. mutans followed by S. sanguinis (Sm-Ss), S. sanguinis followed by S. mutans (Ss-Sm), S. mutans and S. sanguinis inoculated at the same time (Sm=Ss), and the single-species controls S. mutans followed by S. mutans (Sm-Sm) and S. sanguinis followed by S. sanguinis (Ss-Ss). Biofilms were exposed to 10% sucrose 3 times per day for 5 days, and the slabs/biofilms were retrieved to assess demineralization, viable cells, biomass, proteins, polysaccharides, and H2O2 production. Compared with Sm-Sm, primary inoculation with S. sanguinis reduced demineralization (P < 0.05). Both Ss-Sm and Sm=Ss sequences showed reduction in biomass, protein, and polysaccharide content (P < 0.05). The highest S. sanguinis viable count and H2O2 production level and the lowest acidogenicity were observed when S. sanguinis colonized enamel before S. mutans (P < 0.05). Initial enamel adherence with commensal biofilms seems to induce more intense competition against more typically cariogenic species, reducing cariogenicity.IMPORTANCE The concept of caries as an ecological disease implies the understanding of the intricate relationships among the populating microorganisms. Under frequent sugar exposure, some bacteria from the dental biofilm develop pathogenic traits that lead to imbalances (dysbiosis). Depending on which microorganism colonizes the dental surface first, different competition strategies may be developed. Studying the interactions in the entire dental biofilm is not an easy task. In this study, therefore, we modeled the interplay among these microorganisms using a caries-inducing species (S. mutans) and a health-associated species (S. sanguinis). Initial enamel adherence with S. sanguinis seems to induce more intense competition against typically caries-inducing species. Besides continuous exposure with sugars, early colonization of the enamel by highly cariogenic species like S. mutans appears to be needed to develop caries lesions as well. Promoting early colonization by health-associated bacteria such as S. sanguinis could help to maintain oral health, delaying dysbiosis.}, } @article {pmid32825575, year = {2020}, author = {Chen, Z and Schlafer, S and Göstemeyer, G and Schwendicke, F}, title = {Probiotic Effects on Multispecies Biofilm Composition, Architecture, and Caries Activity In Vitro.}, journal = {Microorganisms}, volume = {8}, number = {9}, pages = {}, pmid = {32825575}, issn = {2076-2607}, support = {CSC 201708440261//China Scholarship Council/ ; DFG SCHW 1766/2-2//Deutsche Forschungsgemeinschaft/ ; }, abstract = {While probiotics have been tested for their anti-caries effect in vitro and also clinically, there is a lack of understanding of their effects on complex dental biofilms. We assessed two probiotics, Lactobacillus reuteri and Streptococcus oligofermentans, on a continuous-cultured model containing Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces naeslundii. Cariogenic biofilms were grown on bovine enamel specimens and daily challenged with L. reuteri or S. oligofermentans whole culture (LC/SC) or cell-free supernatant (LS/SS) or medium only (negative control, NC) (n = 21/group) for 10 days. Biofilm was assessed via counting colony-forming units, quantitative polymerase chain reaction, and fluorescence in situ hybridization. Caries activity was determined by pH measurements and by assessing mineral loss (ΔZ) using transverse microradiography. Both LC and SC significantly reduced total and strain-specific cariogenic bacterial numbers (p < 0.05). ΔZ was reduced in LC (mean ± SD: 1846.67 ± 317.89) and SC (3315.87 ± 617.30) compared to NC (4681.48 ± 495.18, p < 0.05). No significant reductions in bacterial numbers and ΔZ was induced by supernatants. Biofilm architecture was not considerably affected by probiotic applications. Viable probiotics L. reuteri and S. oligofermentans, but not their culture supernatants, could reduce the caries activity of multi-species biofilms in vitro.}, } @article {pmid32825203, year = {2020}, author = {Rodríguez-López, P and Filipello, V and Di Ciccio, PA and Pitozzi, A and Ghidini, S and Scali, F and Ianieri, A and Zanardi, E and Losio, MN and Simon, AC and Alborali, GL}, title = {Assessment of the Antibiotic Resistance Profile, Genetic Heterogeneity and Biofilm Production of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolated from The Italian Swine Production Chain.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32825203}, issn = {2304-8158}, support = {Progetto Classyfarm//Ministero della Salute/ ; }, abstract = {The main aim of the present study was to evaluate the level of antibiotic resistance, prevalence and virulence features of methicillin-resistant Staphylococcus aureus (MRSA) isolated from heavy swine at abattoir level and farming environments in Lombardy (Northern Italy). With this scope, 88 different heavy swine farms were surveyed, obtaining a total of n = 440 animal swabs and n = 150 environmental swabs. A total of n = 87 MRSA isolates were obtained, with an overall MRSA incidence of 17.50% (n = 77) among animal samples and a 6.67% (n = 10) among environmental. Molecular characterisation using multilocus sequence typing (MLST) plus spa-typing showed that sequence type ST398/t899 and ST398/t011 were the most commonly isolated genotypes, although other relevant sequence types such as ST1 or ST97 were also found. A lack of susceptibility to penicillins, tetracycline and ceftiofur was detected in >91.95, 85.05 and 48.28% of the isolates, respectively. Resistance to doxycycline (32.18%), enrofloxacin (27.59%) and gentamicin (25.29%) was also observed. Additionally, a remarkable level of antibiotic multiresistance (AMR) was observed representing a 77.01% (n = 67) of the obtained isolates. Genetic analysis revealed that 97.70% and 77.01% of the isolates harboured at least one antibiotic resistance or enterotoxin gene, respectively, pointing out a high isolate virulence potential. Lastly, 55.17% (n = 48) were able to produce measurable amounts of biofilm after 24 h. In spite of the current programmes for antibiotic reduction in intensively farming, a still on-going high level of AMR and virulence potential in MRSA was demonstrated, making this pathogen a serious risk in swine production chain, highlighting once more the need to develop efficient, pathogen-specific control strategies.}, } @article {pmid32824942, year = {2020}, author = {Torres, JP and Senejani, AG and Gaur, G and Oldakowski, M and Murali, K and Sapi, E}, title = {Ex Vivo Murine Skin Model for B. burgdorferi Biofilm.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32824942}, issn = {2079-6382}, abstract = {Borrelia burgdorferi, the causative agent of Lyme disease, has been recently shown to form biofilm structures in vitro and in vivo. Biofilms are tightly clustered microbes characterized as resistant aggregations that allow bacteria to withstand harsh environmental conditions, including the administration of antibiotics. Novel antibiotic combinations have recently been identified for B. burgdorferi in vitro, however, due to prohibiting costs, those agents have not been tested in an environment that can mimic the host tissue. Therefore, researchers cannot evaluate their true effectiveness against B. burgdorferi, especially its biofilm form. A skin ex vivo model system could be ideal for these types of experiments due to its cost effectiveness, reproducibility, and ability to investigate host-microbial interactions. Therefore, the main goal of this study was the establishment of a novel ex vivo murine skin biopsy model for B. burgdorferi biofilm research. Murine skin biopsies were inoculated with B. burgdorferi at various concentrations and cultured in different culture media. Two weeks post-infection, murine skin biopsies were analyzed utilizing immunohistochemical (IHC), reverse transcription PCR (RT-PCR), and various microscopy methods to determine B. burgdorferi presence and forms adopted as well as whether it remained live in the skin tissue explants. Our results showed that murine skin biopsies inoculated with 1 × 10[7] cells of B. burgdorferi and cultured in BSK-H + 6% rabbit serum media for two weeks yielded not just significant amounts of live B. burgdorferi spirochetes but biofilm forms as well. IHC combined with confocal and atomic force microscopy techniques identified specific biofilm markers and spatial distribution of B. burgdorferi aggregates in the infected skin tissues, confirming that they are indeed biofilms. In the future, this ex vivo skin model can be used to study development and antibiotic susceptibility of B. burgdorferi biofilms in efforts to treat Lyme disease effectively.}, } @article {pmid32824901, year = {2020}, author = {El-Sayed, NR and Samir, R and Jamil M Abdel-Hafez, L and Ramadan, MA}, title = {Olive Leaf Extract Modulates Quorum Sensing Genes and Biofilm Formation in Multi-Drug Resistant Pseudomonas aeruginosa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {9}, pages = {}, pmid = {32824901}, issn = {2079-6382}, abstract = {Biofilm acts as a complex barrier against antibiotics. In this study, we investigated the inhibitory activities of Olea europaea (olive) leaves Camellia sinensis (green tea), Styrax benzoin, Ocimum basilicum, Humulus lupulus, Ruta graveolens, and Propolis extracts on the biofilm formation, pyocyanin production, and twitching motility of Pseudomonas aeruginosa isolates. Moreover, we investigated the effect of olive leaf extract on the transcription of some biofilm related genes. A total of 204 isolates of Pseudomonas were collected from different Egyptian hospitals. A susceptibility test, carried out using the disc diffusion method, revealed that 49% of the isolates were multidrug-resistant. More than 90% of the isolates were biofilm-forming, of which 26% were strong biofilm producers. At subinhibitory concentrations, green tea and olive leaf extracts had the highest biofilm inhibitory effects with 84.8% and 82.2%, respectively. The expression levels of lasI, lasR, rhlI, and rhlR treated with these extracts were significantly reduced (p < 0.05) by around 97-99% compared to untreated isolates. This study suggests the ability of olive leaf extract to reduce the biofilm formation and virulence factor production of P. aeruginosa through the down regulation of quorum sensing (QS) genes. This may help in reducing our dependence on antibiotics and to handle biofilm-related infections of opportunistic pathogens more efficiently.}, } @article {pmid32824104, year = {2020}, author = {Raorane, CJ and Lee, JH and Lee, J}, title = {Rapid Killing and Biofilm Inhibition of Multidrug-Resistant Acinetobacter baumannii Strains and Other Microbes by Iodoindoles.}, journal = {Biomolecules}, volume = {10}, number = {8}, pages = {}, pmid = {32824104}, issn = {2218-273X}, support = {2018R1D1A3B07040699//Basic Science Research Program through the NRF funded by the Ministry of Education/International ; 2014R1A6A1031189//Priority Research Center Program through the NRF funded by the Ministry of Education/International ; }, mesh = {Acinetobacter baumannii/drug effects/*physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/growth & development ; Ciprofloxacin/pharmacology ; Colistin/pharmacology ; Drug Resistance, Multiple, Bacterial/*drug effects ; Escherichia coli/growth & development ; Gentamicins/pharmacology ; Indoles/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas aeruginosa/growth & development ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/growth & development ; }, abstract = {Multi-drug resistant Acinetobacter baumannii is well-known for its rapid acclimatization in hospital environments. The ability of the bacterium to endure desiccation and starvation on dry surfaces for up to a month results in outbreaks of health care-associated infections. Previously, indole and its derivatives were shown to inhibit other persistent bacteria. We found that among 16 halogenated indoles, 5-iodoindole swiftly inhibited A. baumannii growth, constrained biofilm formation and motility, and killed the bacterium as effectively as commercial antibiotics such as ciprofloxacin, colistin, and gentamicin. 5-Iodoindole treatment was found to induce reactive oxygen species, resulting in loss of plasma membrane integrity and cell shrinkage. In addition, 5-iodoindole rapidly killed three Escherichia coli strains, Staphylococcus aureus, and the fungus Candida albicans, but did not inhibit the growth of Pseudomonas aeruginosa. This study indicates the mechanism responsible for the activities of 5-iodoindole warrants additional study to further characterize its bactericidal effects on antibiotic-resistant A. baumannii and other microbes.}, } @article {pmid32823918, year = {2020}, author = {Gajewska, J and Chajęcka-Wierzchowska, W}, title = {Biofilm Formation Ability and Presence of Adhesion Genes among Coagulase-Negative and Coagulase-Positive Staphylococci Isolates from Raw Cow's Milk.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32823918}, issn = {2076-0817}, support = {528-0712-0819//Uniwersytet Warmińsko-Mazurski w Olsztynie/ ; }, abstract = {The capacity for biofilm formation is one of the crucial factors of staphylococcal virulence. The occurrence of biofilm-forming staphylococci in raw milk may result in disturbances in technological processes in dairy factories as well as the contamination of finished food products. Therefore, this study aimed to determine the prevalence and characteristics of staphylococcal biofilm formation in raw milk samples and to explore the genetic background associated with biofilm formation in those isolates. The material subjected to testing included 30 cow's milk samples acquired from farms in the central part of Poland. A total of 54 staphylococcal strains were isolated from the samples, of which 42 were classified as coagulase-negative (CoNS) staphylococci belonging to the following species: S. haemolyticus, S. simulans, S. warneri, S. chromogenes, S. hominis, S. sciuri, S. capitis, S. xylosus and S. saprophyticus, while 12 were classified as S. aureus. The study examined the isolates' capacity for biofilm formation and the staphylococcal capacity for slime production and determined the presence of genetic determinants responsible for biofilm formation, i.e., the icaA, icaD, bap and eno and, additionally, among coagulase-negative staphylococci, i.e., the aap, bhp, fbe, embP and atlE. Each tested isolate exhibited the capacity for biofilm formation, of which most of them (79.6%) were capable of forming a strong biofilm, while 5.6% formed a moderate biofilm, and 14.8% a weak biofilm. A capacity for slime production was demonstrated in 51.9% isolates. Most of the tested staphylococcal strains (90.7%) had at least one of the tested genes. Nearly half (47.6%) of the CoNS had the eno gene, while for S. aureus, the eno gene was demonstrated in 58.3% isolates. The frequency of the bap gene occurrence was 23.8% and 25% in CoNS strains and S. aureus, respectively. The fbe gene was demonstrated in only three CoNS isolates. The presence of the icaA was only demonstrated in CoNS strains (24.1%), while the icaD was found in both CoNS strains (21.4%) and S. aureus (100%). Among the CoNS, the presence of the embP (16.7%), aap (28.6%) and atlE (23.8%) was demonstrated as well. The obtained study results indicate that bacteria of the Staphylococcus spp. genus have a strong potential to form a biofilm, which may pose a hazard to consumer health.}, } @article {pmid32823528, year = {2020}, author = {Gabe, V and Zeidan, M and Kacergius, T and Bratchikov, M and Falah, M and Rayan, A}, title = {Lauryl Gallate Activity and Streptococcus mutans: Its Effects on Biofilm Formation, Acidogenicity and Gene Expression.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {16}, pages = {}, pmid = {32823528}, issn = {1420-3049}, mesh = {Biofilms/*drug effects/*growth & development ; Gallic Acid/*analogs & derivatives/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Glass/chemistry ; Hydrogen-Ion Concentration ; Polystyrenes/chemistry ; Streptococcus mutans/*drug effects/genetics/*physiology ; }, abstract = {Streptococcus mutans bacterium is implicated in the pathogenesis of dental caries due to the production of biofilm and organic acids from dietary sucrose. Despite the availability of various means of prophylaxis, caries still has a high worldwide prevalence. Therefore, it is important to find new pharmaceuticals to inhibit S. mutans biofilm formation and acidogenicity. The aim of the current study was to evaluate the activity of lauryl gallate (dodecyl gallate) against S. mutans acidogenicity, the expression of biofilm-associated genes, and biofilm development on solid surfaces (polystyrene, glass). The biofilm quantities produced by S. mutans bacteria were assessed using colorimetric and optical profilometry techniques. Acidogenicity was evaluated by measuring the pH of the biofilm growth medium with microelectrode. Assessment of the expression of gene coding for glucan-binding protein B (gbpB), glucosyltranferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of F1 protein (atpD) was carried out using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The results demonstrate the capacity of lauryl gallate to significantly inhibit S. mutans acidogenicity and biofilm development on solid surfaces, in a dose-dependent manner, compared to untreated bacteria (p < 0.05). The highest activity of lauryl gallate occurred at a concentration of 98.98 µM, at which it suppressed biofilm formation by 100% and lowered pH levels by 98%. The effect of lauryl gallate treatment on gene expression changes, as demonstrated by our RT-qPCR data, was limited to the gtfD gene only, was a significant (48%) decrease in gene expression, obtained for the biofilm-producing bacteria, while a 300% increase in fold change for the same gene occurred in the planktonic cells. It is important to note that in previous studies we showed a broader effect of related derivatives. However, a similar magnitude of difference in effects between biofilm and planktonic cells for the atpD gene was obtained after treatment with octyl gallate and reverse magnitude for the same gene after treatment with ethyl gallate. Therefore, to ascertain the possible direct or indirect effects of lauryl gallate, as well as octyl gallate and ethyl gallate, more research is needed to examine the effects on the amount of enzymes and on the enzymatic activity of the products of the affected genes that are involved in the production and maintenance of biofilm by S. mutans.}, } @article {pmid32823027, year = {2021}, author = {Tang, K and Rosborg, P and Rasmussen, ES and Hambly, A and Madsen, M and Jensen, NM and Hansen, AA and Sund, C and Andersen, HG and Torresi, E and Kragelund, C and Andersen, HR}, title = {Impact of intermittent feeding on polishing of micropollutants by moving bed biofilm reactors (MBBR).}, journal = {Journal of hazardous materials}, volume = {403}, number = {}, pages = {123536}, doi = {10.1016/j.jhazmat.2020.123536}, pmid = {32823027}, issn = {1873-3336}, mesh = {Biodegradation, Environmental ; *Biofilms ; Bioreactors ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {Moving bed biofilm reactors (MBBRs) were placed at two wastewater treatment plants, where they were constantly fed with effluent and intermittently fed with primary wastewater. Each reactor was subjected to different feast/famine periods and flow rates of primary wastewater, thus the different organic and nutrient loads (chemical oxygen demand(COD), ammonium(NH4-N)) resulted in different feast-famine conditions applied to the biomass. In batch experiments, this study investigated the effects of various feast-famine conditions on the biodegradation of micropollutants by MBBRs applied as an effluent polishing step. Rate constants of micropollutant removals were found to be positively correlated to the load of the total COD and NH4-N, indicating that higher organic loads were favourable for the growth of micropollutant degraders in these MBBRs. Rate constant of atenolol was five times higher when the biomass was fed with the highest COD and NH4-N load than it was fed with the lowest COD and NH4-N load. For diclofenac, mycophenolic acid and iohexol, their maximum rate constants were obtained with feeding of COD and NH4-N of approximately 570 mgCOD/d and 40∼60 mgNH4-N/d respectively. This also supports the concept that co-metabolism (rather competition inhibition or catabolic repression) plays an important role in micropollutants biodegradation in wastewater.}, } @article {pmid32818768, year = {2020}, author = {D'Ercole, S and Di Fermo, P and Di Giulio, M and Di Lodovico, S and Di Campli, E and Scarano, A and Tripodi, D and Cellini, L and Petrini, M}, title = {Near-infrared NIR irradiation and sodium hypochlorite: An efficacious association to counteract the Enterococcus faecalis biofilm in endodontic infections.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {210}, number = {}, pages = {111989}, doi = {10.1016/j.jphotobiol.2020.111989}, pmid = {32818768}, issn = {1873-2682}, mesh = {Biofilms/*drug effects/radiation effects ; Dentin/cytology/microbiology/pathology ; Enterococcus faecalis/drug effects/*physiology ; Humans ; In Vitro Techniques ; *Infrared Rays ; Microscopy, Fluorescence ; Polystyrenes/chemistry ; Sodium Hypochlorite/*pharmacology ; }, abstract = {New strategies are necessary for the prevention of endodontic infections caused by Enterococcus faecalis, a common resistant pathogen and biofilm producer. Aim of the present study was to compare the effects of Near-Infrared (NIR) Light-Emitting Diode (LED) irradiation and different concentrations of sodium hypochlorite (NaOCl) alone or combined to each other on the E. faecalis biofilm, on artificial and human dentin surfaces. E. faecalis ATCC 29212 preformed biofilms, on polystyrene wells and on dentin discs, were treated with 880 nm NIR irradiation and NaOCl at 4%, 2.5%, 1% and 0.5% alone and combined to each other (NIR irradiation plus NaOCl 1% or 0.5%) at 5 and 10 min. Treated biofilms were compared to the controls for (i) biofilm biomass evaluation, (ii) CFU count for the quantification of cultivable cells and (iii) cells viability. All the detected experimental conditions displayed a significant reduction of biofilm biomass (p < 0.001) and CFUs/mL (p < 0.01) in respect to the controls on both tested surfaces. The effects on the E. faecalis biomass, colony count and cell viability were not time-dependent except for NaOCl 2.5% and 1% in the biofilm biomass reductions on human dentin discs. NIR-LED irradiation alone showed a reduction of E. faecalis aggregates without interfering with cell viability whereas NaOCl alone expressed a killing effect in a concentration dependent way. The combination of NIR-LED irradiation with NaOCl 1% and 0.5% displayed a double effect of cluster disaggregation and cell killing. In particular, NIR-LED irradiation combined with NaOCl 0.5% displayed an anti-biofilm activity major than those expressed by NaOCl 0.5% alone (p = 0.001) with a reduction of biomass 93% vs 71% and 97% vs 25% after 10 min, on polystyrene wells and human dentin discs, respectively. The innovative use of NIR-LED irradiation combined at short times with low concentration of NaOCl (1% and 0.5%) is capable to reach a significant effect on E. faecalis biofilm, especially on human dentin discs.}, } @article {pmid32817910, year = {2021}, author = {Zhang, X and Zhang, G and Chai, M and Yao, X and Chen, W and Chu, PK}, title = {Synergistic antibacterial activity of physical-chemical multi-mechanism by TiO2 nanorod arrays for safe biofilm eradication on implant.}, journal = {Bioactive materials}, volume = {6}, number = {1}, pages = {12-25}, pmid = {32817910}, issn = {2452-199X}, abstract = {Treatment of implant-associated infection is becoming more challenging, especially when bacterial biofilms form on the surface of the implants. Developing multi-mechanism antibacterial methods to combat bacterial biofilm infections by the synergistic effects are superior to those based on single modality due to avoiding the adverse effects arising from the latter. In this work, TiO2 nanorod arrays in combination with irradiation with 808 near-infrared (NIR) light are proven to eradicate single specie biofilms by combining photothermal therapy, photodynamic therapy, and physical killing of bacteria. The TiO2 nanorod arrays possess efficient photothermal conversion ability and produce a small amount of reactive oxygen species (ROS). Physiologically, the combined actions of hyperthermia, ROS, and puncturing by nanorods give rise to excellent antibacterial properties on titanium requiring irradiation for only 15 min as demonstrated by our experiments conducted in vitro and in vivo. More importantly, bone biofilm infection is successfully treated efficiently by the synergistic antibacterial effects and at the same time, the TiO2 nanorod arrays improve the new bone formation around implants. In this protocol, besides the biocompatible TiO2 nanorod arrays, an extra photosensitizer is not needed and no other ions would be released. Our findings reveal a rapid bacteria-killing method based on the multiple synergetic antibacterial modalities with high biosafety that can be implemented in vivo and obviate the need for a second operation. The concept and antibacterial system described here have large clinical potential in orthopedic and dental applications.}, } @article {pmid32817433, year = {2020}, author = {Mhatre, E and Snyder, DJ and Sileo, E and Turner, CB and Buskirk, SW and Fernandez, NL and Neiditch, MB and Waters, CM and Cooper, VS}, title = {One gene, multiple ecological strategies: A biofilm regulator is a capacitor for sustainable diversity.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {35}, pages = {21647-21657}, pmid = {32817433}, issn = {1091-6490}, support = {R01 GM110444/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Burkholderia cenocepacia/*genetics/growth & development ; Cyclic GMP/analogs & derivatives/genetics ; Directed Molecular Evolution/methods ; Gene Expression Regulation, Bacterial/genetics ; Mutation/genetics ; Phenotype ; Quorum Sensing/*genetics ; Signal Transduction/genetics ; Virulence/genetics ; }, abstract = {Many bacteria cycle between sessile and motile forms in which they must sense and respond to internal and external signals to coordinate appropriate physiology. Maintaining fitness requires genetic networks that have been honed in variable environments to integrate these signals. The identity of the major regulators and how their control mechanisms evolved remain largely unknown in most organisms. During four different evolution experiments with the opportunist betaproteobacterium Burkholderia cenocepacia in a biofilm model, mutations were most frequently selected in the conserved gene rpfR RpfR uniquely integrates two major signaling systems-quorum sensing and the motile-sessile switch mediated by cyclic-di-GMP-by two domains that sense, respond to, and control the synthesis of the autoinducer cis-2-dodecenoic acid (BDSF). The BDSF response in turn regulates the activity of diguanylate cyclase and phosphodiesterase domains acting on cyclic-di-GMP. Parallel adaptive substitutions evolved in each of these domains to produce unique life history strategies by regulating cyclic-di-GMP levels, global transcriptional responses, biofilm production, and polysaccharide composition. These phenotypes translated into distinct ecology and biofilm structures that enabled mutants to coexist and produce more biomass than expected from their constituents grown alone. This study shows that when bacterial populations are selected in environments challenging the limits of their plasticity, the evolved mutations not only alter genes at the nexus of signaling networks but also reveal the scope of their regulatory functions.}, } @article {pmid32817093, year = {2020}, author = {Béchon, N and Jiménez-Fernández, A and Witwinowski, J and Bierque, E and Taib, N and Cokelaer, T and Ma, L and Ghigo, JM and Gribaldo, S and Beloin, C}, title = {Autotransporters Drive Biofilm Formation and Autoaggregation in the Diderm Firmicute Veillonella parvula.}, journal = {Journal of bacteriology}, volume = {202}, number = {21}, pages = {}, pmid = {32817093}, issn = {1098-5530}, mesh = {*Adhesins, Bacterial/genetics/metabolism ; Bacterial Adhesion/*genetics ; Biofilms/*growth & development ; *Type V Secretion Systems/genetics/metabolism ; Veillonella/*physiology ; }, abstract = {The Negativicutes are a clade of the Firmicutes that have retained the ancestral diderm character and possess an outer membrane. One of the best studied Negativicutes, Veillonella parvula, is an anaerobic commensal and opportunistic pathogen inhabiting complex human microbial communities, including the gut and the dental plaque microbiota. Whereas the adhesion and biofilm capacities of V. parvula are expected to be crucial for its maintenance and development in these environments, studies of V. parvula adhesion have been hindered by the lack of efficient genetic tools to perform functional analyses in this bacterium. Here, we took advantage of a recently described naturally transformable V. parvula isolate, SKV38, and adapted tools developed for the closely related Clostridia spp. to perform random transposon and targeted mutagenesis to identify V. parvula genes involved in biofilm formation. We show that type V secreted autotransporters, typically found in diderm bacteria, are the main determinants of V. parvula autoaggregation and biofilm formation and compete with each other for binding either to cells or to surfaces, with strong consequences for V. parvula biofilm formation capacity. The identified trimeric autotransporters have an original structure compared to classical autotransporters identified in Proteobacteria, with an additional C-terminal domain. We also show that inactivation of the gene coding for a poorly characterized metal-dependent phosphohydrolase HD domain protein conserved in the Firmicutes and their closely related diderm phyla inhibits autotransporter-mediated biofilm formation. This study paves the way for further molecular characterization of V. parvula interactions with other bacteria and the host within complex microbiota environments.IMPORTANCEVeillonella parvula is an anaerobic commensal and opportunistic pathogen whose ability to adhere to surfaces or other bacteria and form biofilms is critical for it to inhabit complex human microbial communities such as the gut and oral microbiota. Although the adhesive capacity of V. parvula has been previously described, very little is known about the underlying molecular mechanisms due to a lack of genetically amenable Veillonella strains. In this study, we took advantage of a naturally transformable V. parvula isolate and newly adapted genetic tools to identify surface-exposed adhesins called autotransporters as the main molecular determinants of adhesion in this bacterium. This work therefore provides new insights on an important aspect of the V. parvula lifestyle, opening new possibilities for mechanistic studies of the contribution of biofilm formation to the biology of this major commensal of the oral-digestive tract.}, } @article {pmid32815217, year = {2021}, author = {de-Sousa, ET and Lima-Holanda, AT and Nobre-Dos-Santos, M}, title = {Carbonic anhydrase VI activity in saliva and biofilm can predict early childhood caries: A preliminary study.}, journal = {International journal of paediatric dentistry}, volume = {31}, number = {3}, pages = {361-371}, doi = {10.1111/ipd.12717}, pmid = {32815217}, issn = {1365-263X}, support = {2017/17630-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Biofilms ; Carbonic Anhydrases ; Child ; Child, Preschool ; Cross-Sectional Studies ; *Dental Caries/diagnosis ; Dental Caries Susceptibility ; Humans ; Hydrogen-Ion Concentration ; *Saliva ; }, abstract = {AIM: This study aimed to investigate whether carbonic anhydrase VI activity (CA VIACT), pH, and buffering capacity (BC) in saliva and biofilm could predict the number of lesion occurrence and early childhood caries (ECC).

DESIGN: A cross-sectional study was performed in a sample of 44 children aged 4 to 5 years who were examined regarding their caries status (dmfs + active white spot lesions-WSL) and allocated into two groups: ECC and caries-free (CF). Saliva and biofilm were collected to determine pH, BC, and CA VIACT . Data were analyzed using the Student t test, and multiple linear regression and logistic regression analyses followed by the ROC curve.

RESULTS: Children with ECC exhibited lower pH and BC in saliva and a higher CA VIACT in both saliva and biofilm. Only saliva pH could predict the dmfs + active WSL. In biofilm, if CA VIACT is increased by one pixel/µg, 0.85 ± 0.28 increase is expected in the number of active WSL. Salivary pH and CA VIACT in saliva and biofilm had the power to predict ECC occurrence.

CONCLUSION: Changes in saliva pH and CA VIACT in biofilm predicted the number of lesion occurrence. Furthermore, CA VIACT in both saliva and biofilm can predict propensity for ECC.}, } @article {pmid32812080, year = {2020}, author = {Mitsuwan, W and Wintachai, P and Voravuthikunchai, SP}, title = {Rhodomyrtus tomentosa Leaf Extract and Rhodomyrtone Combat Streptococcus pneumoniae Biofilm and Inhibit Invasiveness to Human Lung Epithelial and Enhance Pneumococcal Phagocytosis by Macrophage.}, journal = {Current microbiology}, volume = {77}, number = {11}, pages = {3546-3554}, pmid = {32812080}, issn = {1432-0991}, support = {PHD/0033/2553//Royal Golden Jubilee (RGJ) Ph.D. Programme/ ; RTA 6180006//TRF Senior Research Scholar/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; Lung ; Macrophages ; Microbial Sensitivity Tests ; Phagocytosis ; *Plant Extracts/pharmacology ; *Streptococcus pneumoniae ; Xanthones ; }, abstract = {Rhodomyrtus tomentosa leaf has been traditionally used to treat many infections. This plant species has been documented to possess a wide spectrum of pharmacological effects. This study aimed to determine the effects of Rhodomyrtus tomentosa leaf extract and its potent purified compound, rhodomyrtone, on Streptococcus pneumoniae virulence factors including biofilms, capsule formation, and invasiveness which play important roles in infections. Ethanol leaf extract and rhodomyrtone demonstrated excellent antibacterial activity against S. pneumoniae with minimal inhibitory concentration (MIC) ranging from 16-32 µg/ml and 0.125-1 µg/ml, respectively. The ability of the extract and rhodomyrtone to prevent biofilm formation and eradicate mature biofilms was assessed. The extract and rhodomyrtone at 1/8 × MIC significantly inhibited biofilm formation in all clinical isolates (P < 0.05). The viability of 8-day biofilm-grown cells significantly decreased following the treatment with the extract and rhodomyrtone at 16 × MIC. 40-90% reduction in the bacterial adhesion and invasion to A549 human alveolar epithelial cells was observed after challenging with the extract and rhodomyrtone, compared with the control within 60 min. Increase in 90-99% phagocytosis of the bacterial cells by RAW264.7 macrophage cell line was detected following the treatment with the extract and rhodomyrtone at 1/2 × MIC, compared with the control. The results suggested potential medicinal benefits of the extract and rhodomyrtone for the treatment of pneumococcal infections.}, } @article {pmid32811553, year = {2020}, author = {Sakano, T and Bittner, EA and Chang, MG and Berra, L}, title = {Above and beyond: biofilm and the ongoing search for strategies to reduce ventilator-associated pneumonia (VAP).}, journal = {Critical care (London, England)}, volume = {24}, number = {1}, pages = {510}, pmid = {32811553}, issn = {1466-609X}, mesh = {Biofilms ; Humans ; Intubation, Intratracheal ; Longitudinal Studies ; *Pneumonia, Ventilator-Associated ; Prospective Studies ; }, } @article {pmid32811434, year = {2020}, author = {Chen, S and Teng, T and Wen, S and Zhang, T and Huang, H}, title = {The aceE involves in mycolic acid synthesis and biofilm formation in Mycobacterium smegmatis.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {259}, pmid = {32811434}, issn = {1471-2180}, support = {31600107//National Natural Science Foundation of China/International ; 81672065//National Natural Science Foundation of China/International ; 5192006//Beijing Natural Science Foundation/International ; 2018ZX10302-301-004//National Major Science and Technology Projects of China/International ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Chromatography, Liquid ; Genetic Complementation Test ; Mass Spectrometry ; Membrane Proteins/genetics/*metabolism ; Microbial Sensitivity Tests ; Microscopy, Electron ; Mutagenesis, Site-Directed ; *Mutation ; Mycobacterium smegmatis/metabolism/*physiology ; Mycolic Acids/*metabolism ; }, abstract = {BACKGROUND: The integrity of cell wall structure is highly significant for the in vivo survival of mycobacteria. We hypothesized that changes in morphology may indicate changes in cell wall metabolism and identified an aceE gene mutant (aceE-mut) which presented a deficient colony morphology on 7H10 agar by screening transposon mutagenesis in Mycolicibacterium smegmatis, basonym Mycobacterium smegmatis (M. smegmatis). This study aimed to identify the functional role of aceE gene in cell wall biosynthesis in M. smegmatis.

RESULTS: We observed that the colony morphology of aceE-mut was quite different, smaller and smoother on the solid culture medium than the wild-type (WT) strain during the transposon library screening of M. smegmatis. Notably, in contrast with the WT, which aggregates and forms biofilm, the aceE-mut lost its ability of growing aggregately and biofilm formation, which are two very important features of mycobacteria. The morphological changes in the aceE-mut strain were further confirmed by electron microscopy which indicated smoother and thinner cell envelope images in contrast with the rough morphology of WT strains. Additionally, the aceE-mut was more fragile to acidic stress and exhibited a pronounced defects in entering the macrophages as compared to the WT. The analysis of mycolic acid (MA) using LC-MS indicated deficiency of alpha-MA and epoxy-MA in aceE-mut strain whereas complementation of the aceE-mut with a wild-type aceE gene restored the composition of MA.

CONCLUSIONS: Over all, this study indicates that aceE gene plays a significant role in the mycolic acid synthesis and affects the colony morphology, biofilm formation of M. smegmatis and bacteria invasion of macrophage.}, } @article {pmid32811177, year = {2020}, author = {Zhao, X and Duan, X and Dai, Y and Zhen, J and Guo, J and Zhang, K and Wang, X and Kuang, Z and Wang, H and Niu, J and Fan, L and Xie, J}, title = {Mycobacterium Von Willebrand factor protein MSMEG_3641 is involved in biofilm formation and intracellular survival.}, journal = {Future microbiology}, volume = {15}, number = {}, pages = {1033-1044}, doi = {10.2217/fmb-2020-0064}, pmid = {32811177}, issn = {1746-0921}, mesh = {Amino Acid Sequence ; Bacterial Proteins/chemistry/genetics/*metabolism ; *Biofilms ; Humans ; Macrophages/microbiology ; Microbial Viability ; Mycobacterium Infections, Nontuberculous/*microbiology ; Mycobacterium smegmatis/genetics/*growth & development/*metabolism ; Mycobacterium tuberculosis/chemistry/genetics/metabolism ; Protein Domains ; Sequence Alignment ; }, abstract = {Aim:Mycobacterium tuberculosis in vitro biofilm is associated with the virulence and persistence capability. Our aim is to delineate factors involved in biofilms development. Materials & methods: We performed transposon mutants screen and found that mutation of MSMEG_3641, a homolog of M. tuberculosis Rv1836c, can change M. smegmatis colony morphology and biofilm. Results: MSMEG_3641 contains a vWA domain that is highly conserved among Mycobacteria. The phenotypes of MSMEG_3641 mutants include disrupted biofilm, weakened migration ability and changed colony morphology. All phenotypes might be contributed to the enhanced cell wall permeability and declined cell aggregation ability. Conclusion: To our knowledge, this is the first report concerning the mycobacteria Von Willebrand factor domain function, especially in colony morphology and biofilm development.}, } @article {pmid32811167, year = {2021}, author = {Cacciatore, FA and Brandelli, A and Malheiros, PDS}, title = {Combining natural antimicrobials and nanotechnology for disinfecting food surfaces and control microbial biofilm formation.}, journal = {Critical reviews in food science and nutrition}, volume = {61}, number = {22}, pages = {3771-3782}, doi = {10.1080/10408398.2020.1806782}, pmid = {32811167}, issn = {1549-7852}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; *Disinfection ; *Food Microbiology ; Food-Processing Industry ; *Nanotechnology ; }, abstract = {The elimination of microbial surface contaminants is one of the most important steps in Good Manufacturing Practices in order to maintain food safety. This is usually achieved by detergents and chemical sanitizers, although an increased demand exists for the use of natural products for disinfection purposes. Several natural substances present antibacterial activity against the main foodborne pathogens, demonstrating great potential for use in the food industry. Some difficulties such as high volatility, residual taste and/or degradation by exposure to harsh processing conditions have been reported. Nanoparticle encapsulation appears as a strategy to protect bioactive compounds, maintaining their antimicrobial activity and providing controlled release as well. This article presents the potential of natural antimicrobials and their combination with nanotechnological strategies as an alternative for food surface disinfection and prevent microbial biofilm formation.}, } @article {pmid32810638, year = {2020}, author = {Papalini, C and Sabbatini, S and Monari, C and Mencacci, A and Francisci, D and Perito, S and Pasticci, MB}, title = {In vitro antibacterial activity of ceftazidime/avibactam in combination against planktonic and biofilm carbapenemase-producing Klebsiella pneumoniae isolated from blood.}, journal = {Journal of global antimicrobial resistance}, volume = {23}, number = {}, pages = {4-8}, doi = {10.1016/j.jgar.2020.07.028}, pmid = {32810638}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents ; Azabicyclo Compounds ; Bacterial Proteins ; Biofilms ; Ceftazidime/pharmacology ; Humans ; *Klebsiella Infections ; Klebsiella pneumoniae/genetics ; Microbial Sensitivity Tests ; Plankton ; Retrospective Studies ; beta-Lactamases ; }, abstract = {OBJECTIVES: The aim of this study was to report on in vitro tests of antibacterial activity of ceftazidime/avibactam in combination against planktonic or biofilm KPC carbapenemase-producing Klebsiella pneumoniae (KPC-Kp), the rate of KPC-Kp blood isolates in University of Perugia Hospital over a 5-year period, and their antimicrobial susceptibility patterns.

METHODS: The antibacterial activity of ceftazidime/avibactam in combination with other antimicrobials was assessed against planktonic and biofilm bacteria by Etest and checkerboard assay. A retrospective review of laboratory data was performed to evaluate the rate of KPC-Kp from blood samples and their antimicrobial susceptibility patterns.

RESULTS: Between 2014 and 2019, 130/4241 (3.1%) KPC-Kp were identified from blood cultures. Their rate increased from 2.3% in 2014-2015 to 4.5% over the last 3 years. Overall, 4.6% (6/130) of KPC-Kp isolates were susceptible to meropenem, 65.4% (85/130) to colistin, 65.1% (84/129) to tigecycline, 34.6% (45/130) to amikacin, 36.2% (42/116) to gentamicin, 40.2% (39/97) to fosfomycin and 91.5% (65/71) to ceftazidime/avibactam. Five of six ceftazidime/avibactam-resistant KPC-Kp were isolated from patients not treated with ceftazidime/avibactam. Synergism was detected both by Etest and checkerboard assay for the combination of ceftazidime/avibactam plus meropenem against planktonic isolates, whilst lower bactericidal activity was observed in biofilm KPC-Kp isolates.

CONCLUSIONS: Our in vitro data suggest that the combination of ceftazidime/avibactam plus meropenem has a synergistic antibacterial activity against planktonic bacteria, whilst a lower activity was detected against biofilm, suggesting worse clinical outcomes whenever biofilm infections are present. Further analyses are required to confirm these results before extending them to clinical practice.}, } @article {pmid32806683, year = {2020}, author = {Kučera, I and Sedláček, V}, title = {Involvement of the cbb3-Type Terminal Oxidase in Growth Competition of Bacteria, Biofilm Formation, and in Switching between Denitrification and Aerobic Respiration.}, journal = {Microorganisms}, volume = {8}, number = {8}, pages = {}, pmid = {32806683}, issn = {2076-2607}, support = {GA16-18476S//Grantová Agentura České Republiky/ ; }, abstract = {Paracoccus denitrificans has a branched electron transport chain with three terminal oxidases transferring electrons to molecular oxygen, namely aa3-type and cbb3-type cytochrome c oxidases and ba3-type ubiquinol oxidase. In the present study, we focused on strains expressing only one of these enzymes. The competition experiments showed that possession of cbb3-type oxidase confers significant fitness advantage during oxygen-limited growth and supports the biofilm lifestyle. The aa3-type oxidase was shown to allow rapid aerobic growth at a high oxygen supply. Activity of the denitrification pathway that had been expressed in cells grown anaerobically with nitrate was fully inhibitable by oxygen only in wild-type and cbb3 strains, while in strains aa3 and ba3 dinitrogen production from nitrate and oxygen consumption occurred simultaneously. Together, the results highlight the importance of the cbb3-type oxidase for the denitrification phenotype and suggest a way of obtaining novel bacterial strains capable of aerobic denitrification.}, } @article {pmid32806643, year = {2020}, author = {Capita, R and Castaño-Arriba, A and Rodríguez-Melcón, C and Igrejas, G and Poeta, P and Alonso-Calleja, C}, title = {Diversity, Antibiotic Resistance, and Biofilm-Forming Ability of Enterobacteria Isolated from Red Meat and Poultry Preparations.}, journal = {Microorganisms}, volume = {8}, number = {8}, pages = {}, pmid = {32806643}, issn = {2076-2607}, support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación (Junta de Castilla y León)/ ; }, abstract = {A total of 44 samples of beef, pork, and poultry preparations were tested. Average counts (log cfu/g) of enterobacteria were 1.99 ± 0.99 (beef preparations), 1.96 ± 1.44 (pork), 2.09 ± 0.92 (chicken), and 2.17 ± 1.06 (turkey) (p > 0.05). Two hundred enterobacterial strains were identified and 13 genera (21 species) were distinguished, including species that are a significant cause of infection. The most common genera were Escherichia (32.5% of strains), Serratia (17.0%), Hafnia (12.5%), and Salmonella (12.0%). Isolates were screened by disc diffusion for susceptibility to 15 antibiotics. A total of 126 strains (63% of the isolates) were multirresistant (having resistance to two or more antibiotics), 46 (23%) were resistant to one antibiotic, and 28 (14%) were sensitive to all antibiotics. The average number of resistances per strain was 2.53 ± 2.05. A higher (p < 0.05) average number of resistances was observed in strains from turkey (3.14 ± 2.55) than in strains from beef (2.15 ± 1.22), pork (2.16 ± 1.39), or chicken (2.44 ± 2.22). At least 50% of strains showed resistance or reduced susceptibility to ampicillin, cefotaxime, ceftazidime, or streptomycin, considered to be "critically important" antimicrobial agents in human medicine. Seventy-nine strains (39.5%), 60 strains (30.0%), and 46 strains (23.0%) were weak, moderate, and strong biofilm producers (crystal violet assay), respectively. This investigation provides evidence that bacteria from red meat and poultry preparations pose major potential risk to consumers.}, } @article {pmid32806515, year = {2020}, author = {Lee, MJ and Kim, JY and Seo, JY and Mangal, U and Cha, JY and Kwon, JS and Choi, SH}, title = {Resin-Based Sealant with Bioactive Glass and Zwitterionic Material for Remineralisation and Multi-Species Biofilm Inhibition.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {32806515}, issn = {2079-4991}, support = {NRF-2018R1C1B6000989 and 2020R1C1C1009703//Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning/ ; }, abstract = {Since pits and fissures are the areas most commonly affected by caries due to their structural irregularity, bioactive resin-based sealant (RBS) may contribute to the prevention of secondary caries. This study aims to investigate the mechanical, physical, ion-release, enamel remineralisation, and antibacterial capabilities of the novel RBS with bioactive glass (BAG) and 2-methacryloyloxyethyl phosphorylcholine (MPC). For the synthesis, 12.5 wt% BAG and 3 wt% MPC were incorporated into RBS. The contact angle, flexural strength, water sorption, solubility, and viscosity were investigated. The release of multiple ions relating to enamel remineralisation was investigated. Further, the attachments of bovine serum albumin, brain heart infusion broth, and Streptococcus mutans on RBS were studied. Finally, the thickness and biomass of a human saliva-derived microsm biofilm model were analysed before aging, with static immersion aging and with thermocycling aging. In comparison to commercial RBS, BAG+MPC increased the wettability, water sorption, solubility, viscosity, and release of multiple ions, while the flexural strength did not significantly differ. Furthermore, RBS with MPC and BAG+MPC significantly reduced protein and bacteria adhesion and suppressed multi-species biofilm attachment regardless of the existence of aging and its type. The novel RBS has great potential to facilitate enamel remineralisation and suppress biofilm adhesion, which could prevent secondary dental caries.}, } @article {pmid32805359, year = {2020}, author = {Zhang, K and Yang, X and Yang, J and Qiao, X and Li, F and Liu, X and Wei, J and Wang, L}, title = {Alcohol dehydrogenase modulates quorum sensing in biofilm formations of Acinetobacter baumannii.}, journal = {Microbial pathogenesis}, volume = {148}, number = {}, pages = {104451}, doi = {10.1016/j.micpath.2020.104451}, pmid = {32805359}, issn = {1096-1208}, mesh = {*Acinetobacter baumannii/genetics ; Alcohol Dehydrogenase/genetics ; Bacterial Proteins ; Biofilms ; Quorum Sensing ; }, abstract = {Acinetobacter baumannii (A. baumannii) is a common opportunistic nosocomial pathogen, which is able to produce biofilms on the surface of indwelling medical devices, and consequentially causes severe infections in clinical settings. In order to identify genes that involved in the biofilm formation of A. baumannii, the differential expression of genes between biofilms and planktonic cells was analyzed by RNAseq assay and validated in clinical isolates. The RNAseq data showed that 264 genes were up-regulated, while 240 genes were down-regulated in the biofilms of A. baumannii. Among them, the gene encoding alcohol dehydrogenase (ADH), a known molecule of bacterial quorum sensing (QS) system that plays a key role in biofilm formation bacteria, was one of the most up-regulated gene in both reference strains and clinical isolates. Functional studies using ADH inhibitor disulfiram and activator taurine further demonstrated that the presence of disulfiram significantly inhibit the cell growth, motility and biofilm formation, paralleled by a decreased expression of QS-related genes, including AbaI, A1S_0109, and A1S_0112, in a dose-dependent manner; vice versa, the addition of ADH activator taurine, and QS molecule C12- homoserine lactone synthase (HSL) led a dose-dependent increase of bacterial growth, motility and biofilm production, along with an increased expression of QS-related genes in both reference strains and clinical isolates of A. baumannii. These results suggested that the ADH was a key molecule able to modulate the QS system and promote the biofilm formation, growth and motility in A. baumannii.}, } @article {pmid32804439, year = {2020}, author = {Ali, S and Jenkins, B and Cheng, J and Lobb, B and Wei, X and Egan, S and Charles, TC and McConkey, BJ and Austin, J and Doxey, AC}, title = {Slr4, a newly identified S-layer protein from marine Gammaproteobacteria, is a major biofilm matrix component.}, journal = {Molecular microbiology}, volume = {114}, number = {6}, pages = {979-990}, pmid = {32804439}, issn = {1365-2958}, mesh = {Aquatic Organisms/genetics ; Bacterial Outer Membrane Proteins/genetics/isolation & purification/ultrastructure ; *Biofilms ; Extracellular Polymeric Substance Matrix/metabolism ; Membrane Glycoproteins/*genetics/isolation & purification/ultrastructure ; Phylogeny ; Protein Conformation ; Pseudoalteromonas/*genetics ; }, abstract = {S-layers are paracrystalline proteinaceous lattices that surround prokaryotic cells, forming a critical interface between the cells and their extracellular environment. Here, we report the discovery of a novel S-layer protein present in the Gram-negative marine organism, Pseudoalteromonas tunicata D2. An uncharacterized protein (EAR28894) was identified as the most abundant protein in planktonic cultures and biofilms. Bioinformatic methods predicted a beta-helical structure for EAR28894 similar to the Caulobacter S-layer protein, RsaA, despite sharing less than 20% sequence identity. Transmission electron microscopy revealed that purified EAR28894 protein assembled into paracrystalline sheets with a unique square lattice symmetry and a unit cell spacing of ~9.1 nm. An S-layer was found surrounding the outer membrane in wild-type cells and completely removed from cells in an EAR28894 deletion mutant. S-layer material also appeared to be "shed" from wild-type cells and was highly abundant in the extracellular matrix where it is associated with outer membrane vesicles and other matrix components. EAR28894 and its homologs form a new family of S-layer proteins that are widely distributed in Gammaproteobacteria including species of Pseudoalteromonas and Vibrio, and found exclusively in marine metagenomes. We propose the name Slr4 for this novel protein family.}, } @article {pmid32803814, year = {2020}, author = {Silva, DAL and Tavares, RM and Nero, LA}, title = {Interference of sanitizers, NaCl and curing salts on Listeria monocytogenes adhesion and subsequent biofilm formation.}, journal = {Letters in applied microbiology}, volume = {71}, number = {5}, pages = {438-443}, doi = {10.1111/lam.13374}, pmid = {32803814}, issn = {1472-765X}, support = {//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; }, mesh = {Acetic Acid/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*growth & development ; Disinfectants/*pharmacology ; Food Handling ; Food Microbiology ; Food-Processing Industry ; Guanidines/pharmacology ; Hydrogen Peroxide/pharmacology ; Listeria monocytogenes/*drug effects/isolation & purification/metabolism ; Listeriosis/prevention & control ; Meat/microbiology ; Microbial Sensitivity Tests ; Peracetic Acid/pharmacology ; Quaternary Ammonium Compounds/pharmacology ; Salts/*pharmacology ; Sodium Chloride/*pharmacology ; }, abstract = {Listeria monocytogenes, a well-known foodborne pathogen and the causative agent of listeriosis, has the ability to persist in food processing environments due to its high adhesion ability in different surfaces, playing an important role in the food industry. The aim of this study was to assess how the main stressing conditions, usually observed in meat processing facilities (sanitizers, NaCl, curing salts), interfere in L. monocytogenes adhesion and biofilm formation. The isolates, representatives of different L. monocytogenes lineages (n = 6) were subjected to four different sanitizers (S1: quaternary ammonium; S2: peracetic acid, hydrogen peroxide and glacial acetic acid, S3: biguanide polyhexamethylene hydrochloride, S4: hydrogen peroxide) to verify adhesion ability and susceptibility based on minimum inhibitory concentration (MIC). In addition, the isolates adhesion and biofilm were assessed up to 72 h under different conditions: sanitizers (MIC values), curing salts and NaCl (both at 5, 7·5, 10%), at different temperatures (4, 12 and 37°C). Despite the effectiveness of sanitizers, isolates presented higher biofilm development when compared to controls in the presence of quaternary ammonium (S1, 1: 1,024) at 4°C, over the tested time (P < 0·05). Furthermore, different responses were observed for the different L. monocytogenes strains tested, providing a better understanding of the persistence of this pathogen in the food processing facilities.}, } @article {pmid32803600, year = {2020}, author = {Tavşanoğlu, ÜN and Başaran Kankılıç, G and Akca, G and Çırak, T and Erdoğan, Ş}, title = {Microplastics in a dam lake in Turkey: type, mesh size effect, and bacterial biofilm communities.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {36}, pages = {45688-45698}, pmid = {32803600}, issn = {1614-7499}, support = {6602a-FEN/18-226//Bozok Üniversitesi/ ; }, mesh = {Biofilms ; Ecosystem ; Environmental Monitoring ; *Lakes ; Microplastics ; Plastics ; Turkey ; *Water Pollutants, Chemical/analysis ; }, abstract = {The evaluation of microplastic (MP) pollution has been drawing attention for the last decades. MP pollution has been studied widely in marine environments, but limited data exists for freshwater ecosystems on potential source and transport of MPs. The type, shape, plastic components, and the color of the MPs were investigated using various-mesh-sizes (300 and 100 μm) nets in four sampling stations of Süreyyabey Dam Lake in Turkey. The growth of bacterial isolates on the MPs surface and surrounding water was also investigated. The type of the MPs and the interaction between the mesh size and the type of the MPs showed significant differences (p < 0.05). Fibers were found to be the most abundant particle type constituting 45% and 80% of the total MPs found in 330-μm and 100-μm mesh sizes, respectively. In total the observed MP abundance in the dam lake was 5.25 particles m[-3], and 4.09 particles m[-3] was observed for 100-μm and 330-μm mesh sizes, respectively. The color of the identified microplastics showed variations among microplastic types; however, the dominant color was transparent in each net. The main plastic components of the MPs are polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, and polypropylene. The microbial community mainly consists of potentially pathogenic strains such as Escherichia coli, Enterococcus faecalis, and Acinetobacter baumanii complex. The current study could contribute valuable background information both for MP pollution and for biofilm composition in a dam. However, the surface of the MPs and biofilm formation should be investigated urgently to understand the vector potential of MPs.}, } @article {pmid32803295, year = {2020}, author = {Du, H and Zhou, L and Lu, Z and Bie, X and Zhao, H and Niu, YD and Lu, F}, title = {Transcriptomic and proteomic profiling response of methicillin-resistant Staphylococcus aureus (MRSA) to a novel bacteriocin, plantaricin GZ1-27 and its inhibition of biofilm formation.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {18}, pages = {7957-7970}, doi = {10.1007/s00253-020-10589-w}, pmid = {32803295}, issn = {1432-0614}, support = {No. 2015BAD16B04//National Research Program of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriocins/genetics ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Proteomics ; Transcriptome ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has become a worrisome superbug, due to its wide distribution and multidrug resistance. To characterize effects of a newly identified plantaricin GZ1-27 on MRSA, transcriptomic and proteomic profiling of MRSA strain ATCC43300 was performed in response to sub-MIC (16 μg/mL) plantaricin GZ1-27 stress. In total, 1090 differentially expressed genes (padj < 0.05) and 418 differentially expressed proteins (fold change > 1.2, p < 0.05) were identified. Centralized protein expression clusters were predicted in biological functions (biofilm formation, DNA replication and repair, and heat-shock) and metabolic pathways (purine metabolism, amino acid metabolism, and biosynthesis of secondary metabolites). Moreover, a capacity of inhibition MRSA biofilm formation and killing biofilm cells were verified using crystal violet staining, scanning electron microscopy, and confocal laser-scanning microscopy. These findings yielded comprehensive new data regarding responses induced by plantaricin and could inform evidence-based methods to mitigate MRSA biofilm formation.}, } @article {pmid32803069, year = {2020}, author = {Sun, W and Liu, L and Yu, Y and Yu, B and Liang, C and Ying, H and Liu, D and Chen, Y}, title = {Biofilm-Related, Time-Series Transcriptome and Genome Sequencing in Xylanase-Producing Aspergillus niger SJ1.}, journal = {ACS omega}, volume = {5}, number = {31}, pages = {19737-19746}, pmid = {32803069}, issn = {2470-1343}, abstract = {In this study, we found that biofilm formation is a critical factor affecting the activity of Aspergillus niger SJ1 xylanase. Xylanase activity increased 8.8% from 1046.88 to 1147.74 U/mL during A. niger SJ1 immobilized fermentation with biofilm formation. Therefore, we carried out the work of genomic analysis and biofilm-related time-series transcriptome analysis of A. niger SJ1 for better understanding of the ability of A. niger SJ to produce xylanase and biofilm formation. Genome annotation results revealed a complete biofilm polysaccharide component synthesis pathway in A. niger SJ1 and five proteins regarding xylanase synthesis. In addition, results of transcriptome analysis revealed that the genes involved in the synthesis of cell wall polysaccharides and amino acid anabolism were highly expressed in the biofilm. Furthermore, the expression levels of major genes in the gluconeogenesis pathway and mitogen-activated protein kinase pathway were examined.}, } @article {pmid32802827, year = {2020}, author = {Hunt, BC and Stanford, D and Xu, X and Li, J and Gaggar, A and Rowe, SM and Raju, SV and Swords, WE}, title = {Haemophilus influenzae persists in biofilm communities in a smoke-exposed ferret model of COPD.}, journal = {ERJ open research}, volume = {6}, number = {3}, pages = {}, pmid = {32802827}, issn = {2312-0541}, support = {P30 DK072482/DK/NIDDK NIH HHS/United States ; R21 AI133445/AI/NIAID NIH HHS/United States ; R35 HL135816/HL/NHLBI NIH HHS/United States ; T32 HL134640/HL/NHLBI NIH HHS/United States ; }, abstract = {RATIONALE: Non-typeable Haemophilus influenzae (NTHi) is a common inhabitant of the human nasopharynx and upper airways that can cause opportunistic infections of the airway mucosa including bronchopulmonary infections in patients with chronic obstructive pulmonary disease (COPD). It is clear that opportunistic infections contribute significantly to inflammatory exacerbations of COPD; however, there remains much to be learned regarding specific host and microbial determinants of persistence and/or clearance in this context.

METHODS: In this study, we used a recently described ferret model for COPD, in which animals undergo chronic long-term exposure to cigarette smoke, to define host-pathogen interactions during COPD-related NTHi infections.

RESULTS: NTHi bacteria colonised the lungs of smoke-exposed animals to a greater extent than controls, and elicited acute host inflammation and neutrophilic influx and activation, along with a significant increase in airway resistance and a decrease in inspiratory capacity consistent with inflammatory exacerbation; notably, these findings were not observed in air-exposed control animals. NTHi bacteria persisted within multicellular biofilm communities within the airway lumen, as evidenced by immunofluorescent detection of bacterial aggregates encased within a sialylated matrix as is typical of NTHi biofilms and differential bacterial gene expression consistent with the biofilm mode of growth.

CONCLUSIONS: Based on these results, we conclude that acute infection with NTHi initiates inflammatory exacerbation of COPD disease. The data also support the widely held hypothesis that NTHi bacteria persist within multicellular biofilm communities in the lungs of patients with COPD.}, } @article {pmid32802683, year = {2020}, author = {Swanson, E}, title = {Breast Implant Illness, Biofilm, and the Role of Capsulectomy.}, journal = {Plastic and reconstructive surgery. Global open}, volume = {8}, number = {7}, pages = {e2999}, pmid = {32802683}, issn = {2169-7574}, } @article {pmid32801807, year = {2020}, author = {Li, Z and Yin, H and Chen, W and Jiang, C and Hu, J and Xue, Y and Yao, D and Peng, Y and Hu, X}, title = {Synergistic Effect of Pseudolaric Acid B with Fluconazole Against Resistant Isolates and Biofilm of Candida tropicalis.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {2733-2743}, pmid = {32801807}, issn = {1178-6973}, abstract = {PURPOSE: Candida tropicalis (C. tropicalis) has emerged as an important fungal pathogen due to its increasing resistance to conventional antifungal agents, especially fluconazole (FLC). Pseudolaric acid B (PAB), a herbal-originated diterpene acid from Pseudolarix kaempferi Gordon, has been reported to possess inhibitory activity against fungus. The present study aims to investigate the antifungal effect of PAB alone and in combination with FLC on planktonic and biofilm cells of C. tropicalis.

METHODS: The antifungal activity of PAB against planktonic isolates was evaluated alone and in combination with FLC using the chequerboard microdilution method and growth curve assay. The anti-biofilm effects were quantified by tetrazolium (XTT) reduction assay, which were further confirmed by scanning electron microscopy (SEM) and fluorescent microscope to observe morphological changes of biofilm treated with PAB and FLC.

RESULTS: It was revealed that PAB alone exhibited similar inhibitory activity against FLC-resistant and FLC-susceptible strains with median MIC ranging from 8 to 16 µg/mL. When administered in combination, synergism was observed in all (13/13) FLC-resistant and (2/9) FLC-susceptible strains with FICI ranging from 0.070 to 0.375. Moreover, the concomitant use of PAB and FLC exhibited a strong dose-dependent synergistic inhibitory effect on the early and mature biofilm, eliminating more than 80% biofilm formation. SEM found that PAB, different from azoles, could significantly inhibit spore germination and destroy the cell integrity causing cell deformation, swelling, collapse and outer membrane perforation.

CONCLUSION: PAB was highly active against FLC-resistant isolates and biofilm of C. tropicalis, particularly when combined with FLC. These findings suggest that PAB may have potential as a novel antifungal agent with different targets from azole drugs.}, } @article {pmid32801701, year = {2020}, author = {Liang, G and Shi, H and Qi, Y and Li, J and Jing, A and Liu, Q and Feng, W and Li, G and Gao, S}, title = {Specific Anti-biofilm Activity of Carbon Quantum Dots by Destroying P. gingivalis Biofilm Related Genes.}, journal = {International journal of nanomedicine}, volume = {15}, number = {}, pages = {5473-5489}, pmid = {32801701}, issn = {1178-2013}, mesh = {Animals ; Anti-Bacterial Agents/adverse effects/*chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects ; Carbon/chemistry/pharmacology ; Escherichia coli/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Metronidazole/chemistry/pharmacology ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Periodontitis/microbiology ; Porphyromonas gingivalis/*drug effects/genetics/physiology ; Quantum Dots/*chemistry ; Rabbits ; Spectrophotometry, Ultraviolet ; Staphylococcus aureus/drug effects ; Tinidazole/chemistry/pharmacology ; Virulence Factors/antagonists & inhibitors ; }, abstract = {INTRODUCTION: Biofilms protect bacteria from antibiotics and this can produce drug-resistant strains, especially the main pathogen of periodontitis, Porphyromonas gingivalis. Carbon quantum dots with various biomedical properties are considered to have great application potential in antibacterial and anti-biofilm treatment.

METHODS: Tinidazole carbon quantum dots (TCDs) and metronidazole carbon quantum dots (MCDs) were prepared by a hydrothermal method with the clinical antibacterial drugs tinidazole and metronidazole, respectively. Then, TCDs and MCDs were characterized by transmission electron microscopy, UV-visible spectroscopy, infrared spectroscopy and energy-dispersive spectrometry. The antibacterial effects were also investigated under different conditions.

RESULTS: The TCDs and MCDs had uniform sizes. The results of UV-visible and energy-dispersive spectrometry confirmed their important carbon polymerization structures and the activity of the nitro group, which had an evident inhibitory effect on P. gingivalis, but almost no effect on other bacteria, including Escherichia coli, Staphylococcus aureus and Prevotella nigrescens. Importantly, the TCDs could penetrate the biofilms to further effectively inhibit the growth of P. gingivalis under the biofilms. Furthermore, it was found that the antibacterial effect of TCDs lies in its ability to impair toxicity by inhibiting the major virulence factors and related genes involved in the biofilm formation of P. gingivalis, thus affecting the self-assembly of biofilm-related proteins.

CONCLUSION: The findings demonstrate a promising new method for improving the efficiency of periodontitis treatment by penetrating the P. gingivalis biofilm with preparations of nano-level antibacterial drugs.}, } @article {pmid32801564, year = {2020}, author = {Jebril, NMT}, title = {Evaluation of two fixation techniques for direct observation of biofilm formation of Bacillus subtilis in situ, on Congo red agar, using scanning electron microscopy.}, journal = {Veterinary world}, volume = {13}, number = {6}, pages = {1133-1137}, pmid = {32801564}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Direct observation, scanning electron microscopy (SEM) is a common method used for the observations of biofilms. N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide) (EDC) fixation method has proven to be a valuable fixation method in the observation of these biofilms. Still, it entails a method of biofilm fixation that can damage slim structures, leading to the impossible observation of biofilm development. In contrast, alcian blue and lysine (ABL) fixation technique appears more glycocalyx of biofilm, fully preserved samples, which may provide much insight into the development of B. subtilis biofilms.

MATERIALS AND METHODS: Here, the evaluation of the fixation of ABL technique for the study of B. subtilis biofilms was carried out in situ, on Congo red agar. In doing so, the comparison to commonly use conventional EDC technique for sample fixation, and observation was carried out. Observations were based on SEM over 30 samples.

RESULTS: Overall, ABL technique provided excellent observation of biofilms formed in situ, on Congo red agar, and revealed slime structures, which have not been observed, much in standard EDC fixation or earlier in other studies of these biofilms in B. subtilis.

CONCLUSION: This study reported the appropriate use of ABL in the fixation technique for the preservation of biofilm of B. subtilis.}, } @article {pmid32801551, year = {2020}, author = {Sachivkina, N and Lenchenko, E and Blumenkrants, D and Ibragimova, A and Bazarkina, O}, title = {Effects of farnesol and lyticase on the formation of Candida albicans biofilm.}, journal = {Veterinary world}, volume = {13}, number = {6}, pages = {1030-1036}, pmid = {32801551}, issn = {0972-8988}, abstract = {BACKGROUND AND AIM: Candida albicans is a dimorphic fungus that has both yeast and filamentous forms. It is part of the normal flora in the oral and genital areas of mammals. One factor for the pathogenicity of C. albicans is its ability to switch from yeast to hyphae. The hyphal form adheres and penetrates tissues more readily than the yeast form and produces biofilms that are associated with chronic infection. Biofilms are protective niches that enable microorganisms to be more resistant to antibiotic treatment, thus allowing for persistent infection. The first stage in the transition from yeast to hyphae involves the formation of a germ tube, and this transition is triggered by interactions with host cells. Germ tube formation is dependent on serum, pH, temperature, and quorum-sensing molecules (QSMs). Farnesol, which is a QSM in C. albicans, can prevent yeast to hyphae conversion and inhibits the growth of fungal biofilm. Lyticase is a synergistic enzyme complex that catalyzes yeast cell lysis by b-1,3-glucanase and is a highly specific alkaline protease that produces protoplasts or spheroplasts. This study investigated the effect of farnesol and lyticase on the formation of C. albicans biofilms.

MATERIALS AND METHODS: C. albicans ATCC 2091 was cultivated on liquid and solid Sabouraud media. The presence of C. albicans was confirmed using HiCrome Candida Agar chromogenic medium. Enzyme activities were assayed using a HiCandida Identification Kit. The morphology and densitometry parameters of C. albicans biofilms were considered in the presence of farnesol (Sigma-Aldrich, Germany), lyticase (from Arthrobacter luteus; Sigma-Aldrich, Germany), and farnesol-lyticase.

RESULTS: This study shows that both farnesol and lyticase possess antifungal activity against C. albicans biofilms. A significant difference among treatment groups (p<0.05) was observed from strong biofilm production to medium and weak.

CONCLUSION: Many studies have been devoted to the antimicrobial action of farnesol. Bacterial enzyme lyticase is also used to degrade fungal cell walls. Both molecules show substantial antifungal properties that are similar to the properties of modern antimycotics. The current study demonstrates that farnesol and lyticase can disrupt biofilm formation in C. albicans ATCC 2091, which is an effective biofilm producer.}, } @article {pmid32801176, year = {2020}, author = {Anderson, AC and Rothballer, M and Altenburger, MJ and Woelber, JP and Karygianni, L and Vach, K and Hellwig, E and Al-Ahmad, A}, title = {Long-Term Fluctuation of Oral Biofilm Microbiota following Different Dietary Phases.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {20}, pages = {}, pmid = {32801176}, issn = {1098-5336}, mesh = {Adult ; Animals ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Diet ; Dietary Fiber/administration & dosage ; Humans ; *Microbiota ; Milk ; Mouth/*microbiology ; Sucrose/administration & dosage ; Yogurt ; }, abstract = {Caries development is associated with shifts in the oral biofilm microbiota and primarily linked to frequent simple carbohydrate consumption. Different nutritional ingredients can either promote or prevent caries development. To investigate the effects of selected ingredients on the oral biofilm microbiota in situ, 11 study participants underwent 3-month-long dietary phases with intake of a regular diet (PI), additional frequent sucrose (PII), milk and yoghurt (PIII), and a diet rich in dietary fiber (PIV) and then returned to their regular diet (PV). Oral biofilm was sampled and analyzed applying 16S rRNA Illumina MiSeq sequencing. Additionally, the effect on the enamel was analyzed by measuring enamel surface roughness with laser scanning microscopy. The beta-diversity results showed that the microbiota in all the following phases differed significantly from PI and that the microbial community in PII was significantly different from all other phases. The abundance of the genus Streptococcus fluctuated over the course of the five phases, with a significant increase in PII (P = 0.01), decreasing in PIII and PIV (PIII and PIV versus PII: P < 0.00001) and increasing again toward PV. Other taxa showed various fluctuations of their abundances, with PV returning approximately to the levels of PI. In conclusion, while elevated sucrose consumption favored caries-promoting non-mutans streptococci, frequent milk and yoghurt intake caused a significant decrease in the abundance of these microbial taxa and in addition reduced enamel surface roughness. These results indicate that modulations of the oral biofilm microbiota can be attained even in adults through dietary changes and corresponding recommendations can be made for the prevention of caries development.IMPORTANCE Caries affects a large proportion of the population worldwide, resulting in high treatment costs. Its etiology can be ascribed to shifts of the microbiota in dental biofilms primarily driven by dietary factors. It is unclear how diet affects the microbial community of plaque biofilm in situ and whether it can be modulated to help prevent caries development. To address these issues, we analyzed changes of the in situ plaque microbiota following 3-month-long dietary changes involving elevated sucrose, dairy, and dietary fiber consumption over a period of 15 months. Applying high-throughput sequencing, we found non-mutans streptococci, a taxonomic group involved in the beginning stages toward microbial dysbiosis, in decreased abundance with elevated dairy and dietary fiber intake. Through analysis of the enamel surface roughness, these effects were confirmed. Therefore, correspondent dietary measures can be recommended for children as well as adults for caries prevention.}, } @article {pmid32799080, year = {2020}, author = {Li, Z and Wang, J and Feng, K and Li, Y and Ding, J and Liu, B and Ren, N and Xing, D}, title = {Rapid recruitment of hydrogen-producing biofilms for hydrogen production in a moving bed biofilm reactor by a sequential immobilization and deoxygenization approach.}, journal = {Bioresource technology}, volume = {317}, number = {}, pages = {123979}, doi = {10.1016/j.biortech.2020.123979}, pmid = {32799080}, issn = {1873-2976}, mesh = {Bacteria ; *Biofilms ; *Bioreactors ; Fermentation ; Hydrogen ; Waste Disposal, Fluid ; }, abstract = {To reduce start-up time and enhance hydrogen production efficiency, a sequential immobilization and deoxygenization (SIDO) strategy for hydrogen production was investigated in continuous-flow moving bed biofilm reactors (MBBRs). The pre-immobilization process accelerated the initial enrichment of hydrogen-producing bacteria (HPB) and promoted the biofilm formation, which contribute to higher hydrogen production efficiency in SIDO-MBBRs compared to a non-immobilized reactor. A similar deoxygenization effect was achieved by inoculation with Pseudomonas aeruginosa compared with N2 sparging, and the P. aeruginosa pre-immobilized MBBR (Pse-MBBR) showed a higher H2 yield in the initial stage of operation. Microbial community analysis found a higher abundance of putative HPB in the range of 82.82-96.56%, with the predominant populations in the SIDO-MBBR assigned to genera Clostridium and Enterobacter. The results suggest that the SIDO-MBBR is an effective approach for rapid recruitment of HPB and start-up of fermentative hydrogen production.}, } @article {pmid32798981, year = {2020}, author = {Balu, S and Bhunia, S and Gachhui, R and Mukherjee, J}, title = {Assessment of polycyclic aromatic hydrocarbon contamination in the Sundarbans, the world's largest tidal mangrove forest and indigenous microbial mixed biofilm-based removal of the contaminants.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {266}, number = {Pt 1}, pages = {115270}, doi = {10.1016/j.envpol.2020.115270}, pmid = {32798981}, issn = {1873-6424}, mesh = {Biofilms ; Environmental Monitoring ; Geologic Sediments ; Polycyclic Aromatic Hydrocarbons/*analysis ; Sphingobacterium ; Water Pollutants, Chemical/*analysis ; Wetlands ; }, abstract = {The distribution of polycyclic aromatic hydrocarbons (PAHs) in the surface water and sediments in five regions of the Indian Sundarbans was assessed. The capability of microbial biofilm communities to sequester PAHs in a biofilm-promoting vessel was evaluated. The total PAH concentration of water and sediments ranged from undetectable to 125 ng ml[-1] and 4880 to 2 × 10[4] ng g[-1] dry weight respectively. The total PAHs concentration of sediments exceeded the Effects Range-Low value and the recommended Effects Range-Median values, implying the PAHs might adversely affect the biota of the Sundarbans. Pyrogenic and petrogenic sources of PAH contamination were identified in most of the sampling sites. Indigenous biofilms were cultivated in a patented biofilm-promoting culture vessel containing liquid media spiked with 16 priority PAHs. Biofilm-mediated 97-100% removal efficiency of 16 PAHs was attained in all media. There was no significant difference between the mean residual PAH from the liquid media collected from hydrophobic and hydrophilic flasks. Residual amounts of acenaphthene (Ace), anthracene (Ant), benzo(b)fluoranthene [B(b)F], benzo(a)pyrene [B(a)P] and benzo(g,h,i)perylene [B(g,h,i)P] showed differences when cultivated in hydrophobic and hydrophilic flasks. The mean residual amounts of total PAHs extracted from biofilm biomasses were variable. A biofilm obtained from a specific sampling site cultured in the hydrophobic flask showed higher PAH sequestration when compared to the removal attained in the hydrophilic flask. Relative abundances of different microbial communities in PAH-sequestering biofilms revealed bacterial phyla including Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Chloroflexi and Planctomycetes as well as members of Ascomycota phylum of fungi. The dominance of Candida tropicalis, Clostridium butyricum, Sphingobacterium multivorum and Paecilomyces fulvus were established.}, } @article {pmid32798808, year = {2020}, author = {Lu, S and Lu, B and Tan, G and Moe, W and Xu, W and Wang, Y and Xing, D and Zhu, X}, title = {Mo2N nanobelt cathodes for efficient hydrogen production in microbial electrolysis cells with shaped biofilm microbiome.}, journal = {Biosensors & bioelectronics}, volume = {167}, number = {}, pages = {112491}, doi = {10.1016/j.bios.2020.112491}, pmid = {32798808}, issn = {1873-4235}, mesh = {*Bioelectric Energy Sources ; Biofilms ; *Biosensing Techniques ; Electrodes ; Electrolysis ; Hydrogen ; *Microbiota ; RNA, Ribosomal, 16S ; Stenotrophomonas ; }, abstract = {High cost platinum (Pt) catalysts limit the application of microbial electrolysis cells (MECs) for hydrogen (H2) production. Here, inexpensive and efficient Mo2N nanobelt cathodes were prepared using an ethanol method with minimized catalyst and binder loadings. The chronopotentiometry tests demonstrated that the Mo2N nanobelt cathodes had similar catalytic activities for H2 evolution compared to that of Pt/C (10 wt%). The H2 production rates (0.39 vs. 0.37 m[3]-H2/m[3]/d), coulombic efficiencies (90% vs. 77%), and overall hydrogen recovery (74% vs. 70%) of MECs with the Mo2N nanobelt cathodes were also comparable to those with Pt/C cathodes. However, the cost of Mo2N nanobelt catalyst ($ 31/m[2]) was much less than that of Pt/C catalysts ($ 1930/m[2]). Furthermore, the biofilm microbiomes at electrodes were studied using the PacBio sequencing of full-length 16S rRNA gene. It indicated Stenotrophomonas nitritireducens as a putative electroactive bacterium dominating the anode biofilm microbiomes. The majority of dominant species in the Mo2N and Pt/C cathode communities belonged to Stenotrophomonas nitritireducens, Stenotrophomonas maltophilia, and Comamonas testosterone. The dominant populations in the cathode biofilms were shaped by the cathode materials. This study demonstrated Mo2N nanobelt catalyst as an alternative to Pt catalyst for H2 production in MECs.}, } @article {pmid32796690, year = {2020}, author = {Grecka, K and Xiong, ZR and Chen, H and Pełka, K and Worobo, RW and Szweda, P}, title = {Effect of Ethanol Extracts of Propolis (EEPs) against Staphylococcal Biofilm-Microscopic Studies.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32796690}, issn = {2076-0817}, support = {S10 RR025502/RR/NCRR NIH HHS/United States ; 2015/18/E/NZ6/00700//Narodowym Centrum Nauki/ ; }, abstract = {Staphylococci growing in the form of biofilm exhibit high resistance to a plethora of antibiotics. The aim of the study was to assess the influence of ethanolic extract of propolis (EEPs) on S. epidermidis ATCC 35984 biofilm using fluorescent microscopy. Propidium iodide (PI) and SYTO 9 were used for differentiation of live and dead cells, and calcofluor white was used to stain the extracellular matrix, the self-produced extracellular polymeric substances (EPS). The outcomes of the research confirm the promising potential of EEPs for eradication of staphylococcal biofilm. However, its activity cannot be classified as fully satisfactory, either in terms of the effectiveness of elimination of bacterial cells or disturbing the EPS structure. A two or even four times higher concentration of EEPs compared to MIC (Minimum Inhibitory Concentration) against planktonic cells (128 µg/mL) was necessary for effective (estimated for 90%) elimination of living cells from the biofilm structure. Unfortunately, even at that concentration of EEPs, the extracellular matrix was only partially disturbed and effectively protected the residual population of living cells of S. epidermidis ATCC 35984. In our opinion, a combination of EEPs with agents disrupting components of EPS, e.g., proteases, lysines, or enzymes degrading extracellular DNA or PIA (polysaccharide intercellular adhesin).}, } @article {pmid32795820, year = {2021}, author = {Hu, J and Tang, Y and Ai, F and Lin, M and Ruan, J}, title = {Biofilm for leaching precious metals from waste printed circuit boards using biocyanidation technology.}, journal = {Journal of hazardous materials}, volume = {403}, number = {}, pages = {123586}, doi = {10.1016/j.jhazmat.2020.123586}, pmid = {32795820}, issn = {1873-3336}, mesh = {Biofilms ; Copper ; *Electronic Waste/analysis ; Pseudomonas ; Recycling ; Silver ; Technology ; }, abstract = {Presently, biocyanidation technology is being usually adopted to recover precious metals from an increasing quantity of waste printed circuit boards. The main aim of this work was to investigate the biofilm formation of Pseudomonas and its ability to leach precious metals. Based on batch experiments, strain 113 showed the highest biofilm-forming activity in optimal culture conditions of pH 7.0, 25 °C, and 1/25 NB medium among the Pseudomonas strains isolated. Both low concentrations of Cu[2+] (500 ppm) and Ag[+] (2.5 ppm) promoted biofilm formation. Under the optimal culture conditions for biofilm formation, the concentration of CN[-] was up to 5.0 ppm. In the continuous silver leaching experiment, the Ag[+] concentration reached 4.0 ppm and the leaching efficiency was 14.7 % at 7 d. The results of this study may contribute to the construction of a bioreactor used for continuous leaching of waste printed circuit boards in an attempt to recover precious metals. Our results may also aid in the industrialization of biocyanidation technology.}, } @article {pmid32794770, year = {2020}, author = {Tavakolian, M and Munguia-Lopez, JG and Valiei, A and Islam, MS and Kinsella, JM and Tufenkji, N and van de Ven, TGM}, title = {Highly Absorbent Antibacterial and Biofilm-Disrupting Hydrogels from Cellulose for Wound Dressing Applications.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {36}, pages = {39991-40001}, doi = {10.1021/acsami.0c08784}, pmid = {32794770}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Bandages ; Biofilms/drug effects ; Cellulose/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Hydrogels/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Particle Size ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; Surface Properties ; Wound Healing/*drug effects ; }, abstract = {In this study, a carboxyl-modified cellulosic hydrogel was developed as the base material for wound dressings. ε-poly-l-lysine, a natural polyamide, was then covalently linked to the hydrogel through a bioconjugation reaction, which was confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR). The antibacterial efficacy of the hydrogel was tested against two model bacteria, Staphylococcus aureus and Pseudomonas aeruginosa, two of the most commonly found bacteria in wound infections. Bacterial viability and biofilm formation after exposure of bacteria to the hydrogels were used as efficacy indicators. Live/Dead assay was used to measure the number of compromised bacteria using a confocal laser scanning microscope. The results show that the antibacterial hydrogel was able to kill approximately 99% of the exposed bacteria after 3 h of exposure. In addition, NIH/3T3 fibroblasts were used to study the biocompatibility of the developed hydrogels. Water-soluble tetrazolium salt (WST)-1 assay was used to measure the metabolic activity of the cells and Live/Dead assay was used to measure the viability of the cells after 24, 48, and 72 h. The developed antibacterial hydrogels are light weight, have a high water-uptake capacity, and show high biocompatibility with the model mammalian cells, which make them a promising candidate to be used for wound dressing applications.}, } @article {pmid32794395, year = {2020}, author = {Mushashe, AM and de Almeida, SA and Ferracane, JL and Merritt, J and Correr, GM}, title = {Effect of biofilm exposure on marginal integrity of composite restorations.}, journal = {American journal of dentistry}, volume = {33}, number = {4}, pages = {201-205}, pmid = {32794395}, issn = {0894-8275}, support = {R35 DE028252/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; *Composite Resins ; *Dental Cavity Preparation ; Dental Marginal Adaptation ; Dental Restoration, Permanent ; Glass ; Microscopy, Electron, Scanning ; Streptococcus mutans ; }, abstract = {PURPOSE: To evaluate the effect of bacterial exposure on the marginal integrity of dentin-resin interfaces for composites with and without bioactive glass (BAG).

METHODS: Cavity preparations of 5 mm width and 1.5 mm depth were machined into dentin disks by means of a computer controlled milling system. After applying the bonding agent, cavity preparations (n=3-5) were restored by incremental technique with experimental resin composites (50:50 BisGMA/TEGDMA: 72wt% filler) with different filler compositions: control - 67 wt% silanated strontium glass and 5wt% aerosol-silica filler and BAG - 57 wt% silanated strontium glass and 15 wt% BAG-65 wt% silica. Samples were then stored in sterile Todd-Hewitt media or co-incubated with Streptococcus mutans (UA 159), at 37°C, 5% CO2 for 1-2 weeks. For samples co-incubated with a living biofilm, a luciferase assay was performed in order to assess its viability. Surfaces were impressed before and after each storage condition and replicas examined in a scanning electron microscope. Using image analysis software (Image J), the discontinuous margins percentage (%DM) was quantitatively assessed. Data were analyzed using two-way ANOVA followed by Tukey's test (α= 0.05).

RESULTS: Gap size ranged between 7-23 µm. The bacterial exposure significantly increased the %DM in both groups predominantly due to the formation of new gap regions. There was no difference between control and BAG composites regarding %DM and the biofilm viability. Bacterial exposure promoted degradation of composite restoration marginal integrity, with no difference between composites with and without BAG.

CLINICAL SIGNIFICANCE: The samples incubated with living biofilm had a higher gap percentage in the margins, confirming the negative effect of cariogenic bacteria on margin degradation. The parameters defined for such synergy can help to understand the multi-factorial aspect of marginal discontinuity and therefore, predict the behavior of composite restorations subjected to the challenging oral environment.}, } @article {pmid32793584, year = {2020}, author = {Leyva Del Rio, D and Sartori, N and Tomblin, NB and Phark, JH and Pardi, V and Murata, RM and Duarte, S}, title = {Bioactive Dental Adhesive System With tt-Farnesol: Effects on Dental Biofilm and Bonding Properties.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {865}, pmid = {32793584}, issn = {2296-4185}, abstract = {BACKGROUND: Composite dental restorations are commonly used to restore cavitated carious lesions. Unfortunately, the main reason for failure is the development of secondary caries adjacent to the restoration. To improve the long-term survival of restorations, antibacterial agents have been added into dental materials. In this study, we assessed the antibacterial and bonding capacity of a commercial universal dental adhesive incorporated with the antibacterial agent tt-farnesol creating 3 experimental adhesives: 0.38% (v/v), 1.90% (v/v), and 3.80% (v/v), plus a control (no incorporation of tt-farnesol).

METHODS: The antibacterial activity was evaluated by assessing colony-forming units (CFU), biofilm dry weight (DW) and production of extracellular insoluble polysaccharides (EIP) at day 2, 3, and 5 of biofilm growth post surface treatment on the surface of composite disks. The effect of tt-farnesol on the chemical and bonding capacity of the adhesive system was assessed via pH analysis, degree of conversion (DC), and microtensile bond strengths to human dentin in both self-etch and etch-and-rinse application modes. A qualitative analysis of the effects of tt-farnesol on biofilm formation was evaluated using scanning electron microscopy (SEM). The sealing capacity of all adhesive systems tested was evaluated using confocal laser scanning microscopy (CLSM).

RESULTS: The 3.80% (v/v) experimental adhesive exhibited the lowest CFU count and lowest production of EIP at day 5. DW and pH values did no exhibit statistical differences among all tested groups. Bond strengths and DC decreased with the incorporation of the antibacterial agent into the adhesive system regardless of the concentration of tt-farnesol.

CONCLUSION: The incorporation of tt-farnesol into the adhesive system significantly reduced bacterial viability and production of EIP; however, the bonding properties of the experimental dental adhesives were altered.}, } @article {pmid32792823, year = {2019}, author = {Nikolaeva, EN and Tsarev, VN and Tsareva, TV and Ippolitov, EV and Arutyunov, SD}, title = {Interrelation of Cardiovascular Diseases with Anaerobic Bacteria of Subgingival Biofilm.}, journal = {Contemporary clinical dentistry}, volume = {10}, number = {4}, pages = {637-642}, pmid = {32792823}, issn = {0976-237X}, abstract = {AIMS: The aim of this study is to study the colonization of subgingival biofilm (SGB) with periodontopathogenic bacteria species and endothelium-dependent vasodilation in patients with coronary heart disease and concomitant periodontitis.

SUBJECTS AND METHODS: Forty-five patients with cardiovascular diseases (CVDs) were examined - 28 women (62%) and 17 men (38%) aged 53-76 years, including 15 patients with acute myocardial infarction (AMI), 15 patients with exertional angina (pectoris), and 15 patients with chronic periodontitis (CP) without CVD. Dental and cardiological health conditions were determined, a biochemical blood test was conducted, endothelium-dependent vasodilation in the brachial artery was measured, and DNA of periodontopathogenic bacteria in SGB was detected.

RESULTS: A reliable interrelation between the colonization of SGB with periodontopathogenic bacteria and development of AMI was established. In AMI patients, the frequency of Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans detection was significantly higher than in the group of participants without cardiovascular disease. The presence of P. gingivalis and A. actinomycetemcomitans in patients with CP directly correlated with severity of periodontal tissue destruction. Endothelium-dependent vasodilation in the brachial artery moderately correlated with patient's cardiological condition (r = 0.3284), biochemical markers of atherosclerosis development (r = 0.6465), and frequency of P. intermedia detection in periodontal pockets (r = 0.3828).

CONCLUSIONS: Periodontal status in patients with AMI is characterized by unsatisfactory and poor hygiene, increased indices of bleeding on probing, and periodontal pocket depth in comparison to groups of patients with angina pectoris and CP without cardiovascular pathology.}, } @article {pmid32792334, year = {2020}, author = {Schilcher, K and Horswill, AR}, title = {Staphylococcal Biofilm Development: Structure, Regulation, and Treatment Strategies.}, journal = {Microbiology and molecular biology reviews : MMBR}, volume = {84}, number = {3}, pages = {}, pmid = {32792334}, issn = {1098-5557}, support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects/*growth & development ; Cell Proliferation ; Drug Resistance, Microbial ; Extracellular Matrix/metabolism ; Humans ; Immune Evasion ; Phage Therapy ; Quorum Sensing ; Signal Transduction ; Staphylococcal Infections/drug therapy/immunology/*microbiology ; Staphylococcus aureus/immunology/*physiology ; Staphylococcus epidermidis/immunology/*physiology ; Trans-Activators/metabolism ; }, abstract = {In many natural and clinical settings, bacteria are associated with some type of biotic or abiotic surface that enables them to form biofilms, a multicellular lifestyle with bacteria embedded in an extracellular matrix. Staphylococcus aureus and Staphylococcus epidermidis, the most frequent causes of biofilm-associated infections on indwelling medical devices, can switch between an existence as single free-floating cells and multicellular biofilms. During biofilm formation, cells first attach to a surface and then multiply to form microcolonies. They subsequently produce the extracellular matrix, a hallmark of biofilm formation, which consists of polysaccharides, proteins, and extracellular DNA. After biofilm maturation into three-dimensional structures, the biofilm community undergoes a disassembly process that leads to the dissemination of staphylococcal cells. As biofilms are dynamic and complex biological systems, staphylococci have evolved a vast network of regulatory mechanisms to modify and fine-tune biofilm development upon changes in environmental conditions. Thus, biofilm formation is used as a strategy for survival and persistence in the human host and can serve as a reservoir for spreading to new infection sites. Moreover, staphylococcal biofilms provide enhanced resilience toward antibiotics and the immune response and impose remarkable therapeutic challenges in clinics worldwide. This review provides an overview and an updated perspective on staphylococcal biofilms, describing the characteristic features of biofilm formation, the structural and functional properties of the biofilm matrix, and the most important mechanisms involved in the regulation of staphylococcal biofilm formation. Finally, we highlight promising strategies and technologies, including multitargeted or combinational therapies, to eradicate staphylococcal biofilms.}, } @article {pmid32788689, year = {2020}, author = {Barrientos-Moreno, L and Molina-Henares, MA and Ramos-González, MI and Espinosa-Urgel, M}, title = {Arginine as an environmental and metabolic cue for cyclic diguanylate signalling and biofilm formation in Pseudomonas putida.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {13623}, pmid = {32788689}, issn = {2045-2322}, mesh = {Arginine/*metabolism ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; *Gene Expression Regulation, Bacterial ; Pseudomonas Infections/*microbiology ; Pseudomonas putida/*growth & development/metabolism ; }, abstract = {Cyclic diguanylate (c-di-GMP) is a broadly conserved intracellular second messenger that influences different bacterial processes, including virulence, stress tolerance or social behaviours and biofilm development. Although in most cases the environmental cue that initiates the signal transduction cascade leading to changes in cellular c-di-GMP levels remains unknown, certain L- and D-amino acids have been described to modulate c-di-GMP turnover in some bacteria. In this work, we have analysed the influence of L-amino acids on c-di-GMP levels in the plant-beneficial bacterium Pseudomonas putida KT2440, identifying L-arginine as the main one causing a significant increase in c-di-GMP. Both exogenous (environmental) and endogenous (biosynthetic) L-arginine influence biofilm formation by P. putida through changes in c-di-GMP content and altered expression of structural elements of the biofilm extracellular matrix. The contribution of periplasmic binding proteins forming part of amino acid transport systems to the response to environmental L-arginine was also studied. Contrary to what has been described in other bacteria, in P. putida these proteins seem not to be directly responsible for signal transduction. Rather, their contribution to global L-arginine pools appears to determine changes in c-di-GMP turnover. We propose that arginine plays a connecting role between cellular metabolism and c-di-GMP signalling in P. putida.}, } @article {pmid32787095, year = {2020}, author = {Fei, Y and Wu, J and An, HW and Zhu, K and Peng, B and Cai, J and Zhang, Y and Li, LL and Wang, H and Huang, Z}, title = {Identification of New Nitric Oxide-Donating Peptides with Dual Biofilm Eradication and Antibacterial Activities for Intervention of Device-Related Infections.}, journal = {Journal of medicinal chemistry}, volume = {63}, number = {17}, pages = {9127-9135}, doi = {10.1021/acs.jmedchem.9b01832}, pmid = {32787095}, issn = {1520-4804}, mesh = {Amino Acid Sequence ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology/therapeutic use ; Antimicrobial Cationic Peptides/*chemistry/pharmacology/therapeutic use ; Biofilms/*drug effects ; Cephalosporins/pharmacology ; Escherichia coli/physiology ; Hemolysis/drug effects ; Injections, Subcutaneous ; Mice ; Nitric Oxide/metabolism ; Nitric Oxide Donors/*chemistry/pharmacology/therapeutic use ; Staphylococcal Infections/drug therapy/pathology ; Staphylococcus aureus/physiology ; }, abstract = {Implantable medical device-related infections with biofilms have become a significant challenge in clinics. Based on the potential bacteria biofilm dispersing effect of nitric oxide (NO) and the unique antibacterial activity of antimicrobial peptides (AMP), we synthesized five peptides and selected the most potent one to conjugate its N-terminal with a furoxan moiety to offer a hitherto unknown NO-donating antimicrobial peptide (FOTyr-AMP), which exhibited Staphylococcus aureus and Escherichia coli biofilm dispersion and eradication, and potent antibacterial activities in vitro. In an implanted biofilm infection mice model, topical subcutaneous injection of FOTyr-AMP allowed synergetic eradication of bacterial biofilms and potent antibacterial activity, superior to the antibiotic cephalosporin C. Given the low hemolysis effect, little influence on the blood pressure, and potent in vivo efficacy of FOTyr-AMP, it is clear that subcutaneous administration of FOTyr-AMP could be a promising approach for the intervention of medical device-related biofilm infections with desirable safety.}, } @article {pmid32786580, year = {2020}, author = {Chen, X and Yang, L and Sun, J and Wei, W and Liu, Y and Ni, BJ}, title = {Influences of Longitudinal Heterogeneity on Nitrous Oxide Production from Membrane-Aerated Biofilm Reactor: A Modeling Perspective.}, journal = {Environmental science & technology}, volume = {54}, number = {17}, pages = {10964-10973}, doi = {10.1021/acs.est.0c04067}, pmid = {32786580}, issn = {1520-5851}, mesh = {Biofilms ; *Bioreactors ; Nitrogen ; *Nitrous Oxide/analysis ; Wastewater ; }, abstract = {As a promising technology for sustainable nitrogen removal from wastewater, the membrane-aerated biofilm reactors (MABRs) performing autotrophic deammonification are faced with the problem of unwanted production of nitrous oxide (N2O, a potent greenhouse gas). As a common tool to study N2O production from such an MABR, the traditional one-dimensional modeling approach fails to simulate the existence of longitudinal gradients in the reactor and therefore might render N2O production significantly deviated from reality. To this end, this work aims to study the influences of key longitudinal gradients (i.e., in oxygen, liquid-phase components, and biofilm thickness) on the N2O production from a typical MABR performing autotrophic deammonification by applying a modified version of a newly developed compartmental model. Through comparing the modeling results of different reactor configurations, this work reveals that the single impact of the longitudinal gradients studied on the N2O production from the MABR follows the order: oxygen (significant) > liquid-phase components (slight) > biofilm thickness (almost none). When multiple longitudinal gradients are present, they become correlated and would jointly influence the N2O production and nitrogen removal of the MABR. The results also show the need for multispot measurements to get an accurate representation of spatial biofilm features of the MABR configuration with the membrane lumen designed/operated as a plug flow reactor. While the traditional modeling approach is acceptable to evaluate the nitrogen removal in most cases, it might overestimate or underestimate the N2O production from the MABR with at least one of the longitudinal gradients in oxygen and liquid-phase components. For such an MABR, the longitudinal heterogeneity in biofilm thickness and the number of biofilm thickness classes to be included in the model would also make a difference to the simulation results, especially the N2O production. The work also proposes that under the studied conditions, proper design/operation of the MABR in consideration of longitudinal heterogeneity has the theoretical potential of reducing the N2O production by 77% without significantly compromising the nitrogen removal.}, } @article {pmid32785735, year = {2021}, author = {Balan, B and Dhaulaniya, AS and Varma, DA and Sodhi, KK and Kumar, M and Tiwari, M and Singh, DK}, title = {Microbial biofilm ecology, in silico study of quorum sensing receptor-ligand interactions and biofilm mediated bioremediation.}, journal = {Archives of microbiology}, volume = {203}, number = {1}, pages = {13-30}, pmid = {32785735}, issn = {1432-072X}, mesh = {Bacteria/*metabolism ; Bacterial Proteins/*metabolism ; *Biodegradation, Environmental ; *Biofilms ; Computer Simulation ; *Ligands ; Quorum Sensing/*physiology ; }, abstract = {Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric substances (EPS). This review attempts to explain biofilm architecture, development phases, and forces that drive bacteria to promote biofilm mode of growth. Bacterial chemical communication, also known as Quorum sensing (QS), which involves the production, detection, and response to small molecules called autoinducers, is highlighted. The review also provides a brief outline of interspecies and intraspecies cell-cell communication. Additionally, we have performed docking studies using Discovery Studio 4.0, which has enabled our understanding of the prominent interactions between autoinducers and their receptors in different bacterial species while also scoring their interaction energies. Receptors, such as LuxN (Phosphoreceiver domain and RecA domain), LuxP, and LuxR, interacted with their ligands (AI-1, AI-2, and AHL) with a CDocker interaction energy of - 31.6083 kcal/mole; - 34.5821 kcal/mole, - 48.2226 kcal/mole and - 41.5885 kcal/mole, respectively. Since biofilms are ideal for the remediation of contaminants due to their high microbial biomass and their potential to immobilize pollutants, this article also provides an overview of biofilm-mediated bioremediation.}, } @article {pmid32785202, year = {2020}, author = {Sengupta, B and Adhikari, P and Mallet, E and Havner, R and Pradhan, P}, title = {Spectroscopic Study on Pseudomonas Aeruginosa Biofilm in the Presence of the Aptamer-DNA Scaffolded Silver Nanoclusters.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {16}, pages = {}, pmid = {32785202}, issn = {1420-3049}, support = {P20 GM103476/GM/NIGMS NIH HHS/United States ; Research and Creative Activity Grant number 150030-26214-150//Stephen F. Austin State University/ ; AN-0008//Welch Foundation/ ; 1800732//National Science Foundation/ ; }, mesh = {Aptamers, Nucleotide/*chemistry/metabolism ; Base Sequence ; *Biofilms/growth & development ; Circular Dichroism ; Hydrophobic and Hydrophilic Interactions ; Metal Nanoparticles/*chemistry ; Pseudomonas aeruginosa/*chemistry/metabolism/physiology ; Silver/*chemistry ; Spectrometry, Fluorescence ; }, abstract = {We report the effectiveness of silver nanocluster (Ag-NC) against the biofilm of Pseudomonas aeruginosa (PA). Two DNA aptamers specific for PA and part of their sequences were chosen as templates for growing the Ag-NC. While circular dichroism (CD) studies determined the presence of secondary structures, UV/Vis absorption, and fluorescence spectroscopic studies confirmed the formation of the fluorescent Ag-NC on the DNA templates. Furthermore, mesoscopic physics-based partial wave spectroscopy (PWS) was used to analyze the backscattered light signal that can detect the degree of nanoscale mass density/refractive index fluctuations to identify the biofilm formation, comparatively among the different aptamers with respect to the control sample. The importance of the secondary structure of the aptamer DNA in targeting, successfully binding with the cells and delivering the Ag-NC, is evidenced by the decrease in disorder strength (Ld) of the Ag-NC treated samples compared to the untreated PA cells, which showed the abundance of higher Ld in the PWS studies. The higher Ld value attributed to the higher mass density fluctuations and the formation of biofilm. We envision this study to open a new avenue in using a powerful optical microscopic technique like PWS in detection, and DNA aptamer enclosed silver nanoclusters to prevent biofilms for opportunist pathogens like Pseudomonas aeruginosa.}, } @article {pmid32784631, year = {2020}, author = {Ćwiek, K and Korzekwa, K and Tabiś, A and Bania, J and Bugla-Płoskońska, G and Wieliczko, A}, title = {Antimicrobial Resistance and Biofilm Formation Capacity of Salmonella enterica Serovar Enteritidis Strains Isolated from Poultry and Humans in Poland.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32784631}, issn = {2076-0817}, abstract = {Salmonella enterica ser. Enteritidis (S. enterica ser. Enteritidis) is the most frequently detected serovar in human salmonellosis, and its ability to produce a biofilm and the risk of transmission from animals and food of animal origin to humans are significant. The main aim of the present work was to compare S. enterica ser. Enteritidis strains isolated from poultry and human feces in terms of resistance profiles, prevalence of selected resistance genes, and their potential for biofilm formation, by assessing their biofilm growth intensity, the prevalence and expression of selected genes associated with this phenomenon, and the correlation between increased antimicrobial resistance and biofilm formation ability of the two tested groups of S. enterica ser. Enteritidis. This study showed a difference in antimicrobial resistance (minimal inhibitory concentration value) between S. enterica ser. Enteritidis groups; however, the majority of multidrug-resistant (MDR) strains were isolated from poultry (environmental samples from chicken broilers, turkey broilers, and laying hens). Differences in the prevalence of resistance genes were observed; the most common gene among poultry strains was floR, and that among strains from humans was blaTEM. S. enterica ser. Enteritidis strains isolated from poultry under the tested incubation conditions exhibited better biofilm growth than strains isolated from humans. A higher level of gene expression associated with the production of cellulose was only detected in the S48 strain isolated from poultry. On the other hand, increased expression of genes associated with quorum sensing was observed in two strains isolated from poultry farms and one strain isolated from human feces.}, } @article {pmid32784363, year = {2020}, author = {Quintieri, L and Caputo, L and De Angelis, M and Fanelli, F}, title = {Genomic Analysis of Three Cheese-Borne Pseudomonas lactis with Biofilm and Spoilage-Associated Behavior.}, journal = {Microorganisms}, volume = {8}, number = {8}, pages = {}, pmid = {32784363}, issn = {2076-2607}, support = {3QKDQX3//Apulia Region, Italy/ ; }, abstract = {Psychrotrophic pseudomonads cause spoilage of cold fresh cheeses and their shelf-life reduction. Three cheese-borne Pseudomonas sp., ITEM 17295, ITEM 17298, and ITEM 17299 strains, previously isolated from mozzarella cheese, revealed distinctive spoilage traits based on molecular determinants requiring further investigations. Genomic indexes (ANI, isDDH), MLST-based phylogeny of four housekeeping genes (16S rRNA, gyrB, rpoB and rpoD) and genome-based phylogeny reclassified them as Pseudomonas lactis. Each strain showed distinctive phenotypic traits at 15 and 30 °C: ITEM 17298 was the highest biofilm producer at both temperatures, whilst ITEM 17295 and ITEM 17299 showed the strongest proteolytic activity at 30 °C. A wider pattern of pigments was found for ITEM 17298, while ITEM 17295 colonies were not pigmented. Although the high genomic similarity, some relevant molecular differences supported this phenotypic diversity: ITEM 17295, producing low biofilm amount, missed the pel operon involved in EPS synthesis and the biofilm-related Toxin-Antitoxin systems (mqsR/mqsA, chpB/chpS); pvdS, required for the pyoverdine synthesis, was a truncated gene in ITEM 17295, harboring, instead, a second aprA involved in milk proteolysis. This work provided new insight into the food spoiler microbiota by identifying these mozzarella cheese spoilers as P. lactis; molecular targets to be exploited in the development of novel preservative strategies were also revealed.}, } @article {pmid32784083, year = {2020}, author = {Rodrigues de Assis, L and Calijuri, ML and Assemany, PP and Silva, TA and Teixeira, JS}, title = {Innovative hybrid system for wastewater treatment: High-rate algal ponds for effluent treatment and biofilm reactor for biomass production and harvesting.}, journal = {Journal of environmental management}, volume = {274}, number = {}, pages = {111183}, doi = {10.1016/j.jenvman.2020.111183}, pmid = {32784083}, issn = {1095-8630}, mesh = {Biofilms ; Biomass ; *Chlorella vulgaris ; *Microalgae ; Ponds ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {The use of algal biomass still faces challenges associated with the harvesting stages. To address this issue, we propose an innovative hybrid system, in which a biofilm reactor (BR) operates as an algal biomass production and harvesting unit connected to a high-rate algal pond (HRAP), a wastewater treatment unit. BR did not interfered with the biomass chemical composition (protein = 32%, carbohydrates = 11% and total lipids = 18%), with the wastewater treatment (removals efficiency: chemical oxygen demand = 59%, ammonia nitrogen = 78%, total phosphorus = 16% and Escherichia coli = 1 log unit), and did not alter the sedimentation characteristics of the biomass (sludge volume index = 29 mg/L and humidity content = 92%) in the secondary settling tank of the hybrid system. On the other hand, the results showed that this technology achieved a biomass production about 2.6x greater than the conventional system without a BR, and the efficiency of harvesting of the hybrid system was 61%, against 22% obtained with the conventional system. In addition, the BR promoted an increase in the density (~1011 org/m[2]) and diversity of microalgae in the hybrid system. Chlorella vulgaris was the most abundant species (>60%) from the 4th week of operation until the end of the experiment. Hence, results confirm that the integration of BR into a wastewater treatment plant optimised the production and harvesting of biomass of the hybrid system, making it a promising technology. The importance of economic and environmental analysis studies of BR is highlighted in order to enable its implementation on a large scale.}, } @article {pmid32782291, year = {2020}, author = {Kot, B and Sytykiewicz, H and Sprawka, I and Witeska, M}, title = {Effect of manuka honey on biofilm-associated genes expression during methicillin-resistant Staphylococcus aureus biofilm formation.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {13552}, pmid = {32782291}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/*drug effects ; *Honey ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Staphylococcal Infections/*drug therapy/microbiology ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) are among the most important biofilm-forming pathogens responsible for hard-to-treat infections. Looking for alternatives to antibiotics that prevent biofilm formation, we investigated the effects of manuka honey on the transcriptional profile of genes essential for staphylococcal biofilm formation using qRT-PCR. mRNA from two hospital MRSA strains (strong and weak biofilm producer) were isolated after 4, 8, 12 and 24 h from cells grown in biofilm. Manuka honey at 1/2 minimum biofilm inhibition concentration (MBIC) significantly reduced MRSA cell viability in biofilm. Manuka honey downregulated the genes encoding laminin- (eno), elastin- (ebps) and fibrinogen binding protein (fib), and icaA and icaD involved in biosynthesis of polysaccharide intercellular adhesin in both weakly and strongly adhering strain compared to the control (untreated biofilm). Expression levels of cna (collagen binding protein) and map/eap (extracellular adherence protein-Eap) were reduced in weakly adhering strain. The lowest expression of investigated genes was observed after 12 h of manuka honey treatment at 1/2 MBIC. This study showed that the previously unknown mechanism of manuka honey action involved inhibition of S. aureus adhesion due to reduction in expression of crucial genes associated with staphylococcal biofilm.}, } @article {pmid32781835, year = {2020}, author = {Prado, MM and Kovalski, DJ and Torrez, WB and Bueno-Silva, B and Feres, M and de Almeida, J and Porto, LM}, title = {Development of a multispecies periodontal biofilm model within a stirred bioreactor.}, journal = {Biofouling}, volume = {36}, number = {6}, pages = {725-735}, doi = {10.1080/08927014.2020.1805600}, pmid = {32781835}, issn = {1029-2454}, mesh = {Animals ; Bacteria ; *Biofilms ; *Bioreactors ; Cattle ; }, abstract = {The objective of this work was to develop a subgingival biofilm model using a stirred bioreactor. Discs of bovine teeth were adapted to a stirred bioreactor filled with a culture medium containing bacterial species associated with periodontal health or disease. After anaerobic incubation, the biofilms growing on the substratum surfaces were collected and analyzed. The mean number of Colony-forming Units (CFUs) varied, but with no difference between 3 and 7 days of biofilm formation (p > 0.05). Scanning Electron Microscopy (SEM) analysis showed a uniform biofilm layer covering the cement layer of the root surface containing bacteria with diverse morphology. In checkerboard DNA-DNA hybridization, bacterial species were identified in both biofilms. In conclusion, a subgingival biofilm model was developed using a stirred bioreactor, allowing the in vitro reproduction of complex microbial communities. This is an advanced model that may be useful to mimic complex clinical periodontal biofilms.}, } @article {pmid32781280, year = {2021}, author = {Song, P and Xiao, Y and Ren, ZJ and Brooks, JP and Lu, L and Zhou, B and Zhou, Y and Freguia, S and Liu, Z and Zhang, N and Li, Y}, title = {Electrochemical biofilm control by reconstructing microbial community in agricultural water distribution systems.}, journal = {Journal of hazardous materials}, volume = {403}, number = {}, pages = {123616}, doi = {10.1016/j.jhazmat.2020.123616}, pmid = {32781280}, issn = {1873-3336}, mesh = {Biofilms ; *Biofouling ; *Microbiota ; Water ; *Water Purification ; }, abstract = {Biofilm causes considerable technical challenges in agricultural water distribution systems. Electrochemical treatment (ECT) is a potential technique for controlling biofilm in the systems. Given the limited information on how ECT performance changes of irrigation systems and microbial biofilm community shifts. In this study, the effect of anti-biofilm was assessed. Illumina Miseq high-throughput sequencing, combined with molecular ecological network analysis, were applied to detect the effects of ECT on attached biofilm microbial communities. We found that ECT effectively mitigated biofilm formation with the fixed-biofilm biomass reduced by 37.5 %-79.9 %. ECT significantly shifted the bacterial community structures in the biofilm, reduced the communities' diversity, and changed the dominant species. Molecular ecological network analysis showed that the complexity and size of bacterial networks were destabilized under ECT and decreased the interactions among bacterial species. The reconstruction in bacterial community and networks were responsible for the decline in extracellular polymer substances and biofilm biomass. However, chlorine-resistant bacteria were found increased after ECT, and higher relative abundance and low biofilm removal was identified in continuous ECT as compared with intermittent ECT. These results aimed to highlight the opportunity for biofouling mitigation by ECT for irrigation systems, and reveal the potential anti-biofilm microbial mechanisms of ECT.}, } @article {pmid32780824, year = {2021}, author = {Matsumoto, Y and Kurakado, S and Sugita, T}, title = {Evaluating Candida albicans biofilm formation in silkworms.}, journal = {Medical mycology}, volume = {59}, number = {2}, pages = {201-205}, doi = {10.1093/mmy/myaa064}, pmid = {32780824}, issn = {1460-2709}, mesh = {Animals ; Biofilms/*growth & development ; Bombyx/*microbiology ; Candida albicans/*growth & development/*physiology ; Equipment and Supplies/microbiology ; Polyurethanes ; }, abstract = {Candida albicans is a pathogenic fungus that causes deep mycosis in immunocompromised patients and forms a biofilm on catheter surfaces. Here we showed that C. albicans infection of silkworms led to biofilm formation on the surface of polyurethane fibers, a catheter substrate material, while inside the silkworm body. Silkworms inserted with polyurethane fibers survived for at least 48 hours. When silkworms inserted with polyurethane fibers were subsequently infected with C. albicans, biofilm formed on the surface of the polyurethane fiber within 24 hours in the silkworm body. These results suggest that silkworms can be used to evaluate C. albicans biofilm formation.}, } @article {pmid32780778, year = {2020}, author = {Jiang, W and Ubhayasekera, W and Breed, MC and Norsworthy, AN and Serr, N and Mobley, HLT and Pearson, MM and Knight, SD}, title = {MrpH, a new class of metal-binding adhesin, requires zinc to mediate biofilm formation.}, journal = {PLoS pathogens}, volume = {16}, number = {8}, pages = {e1008707}, pmid = {32780778}, issn = {1553-7374}, support = {R01 AI059722/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/chemistry/genetics/*metabolism ; Amino Acid Sequence ; *Biofilms ; Fimbriae Proteins/chemistry/genetics/*metabolism ; Humans ; Proteus Infections/metabolism/microbiology ; Proteus mirabilis/chemistry/genetics/*metabolism ; Sequence Alignment ; Urinary Tract Infections/metabolism/*microbiology ; Zinc/chemistry/*metabolism ; }, abstract = {Proteus mirabilis, a Gram-negative uropathogen, is a major causative agent in catheter-associated urinary tract infections (CAUTI). Mannose-resistant Proteus-like fimbriae (MR/P) are crucially important for P. mirabilis infectivity and are required for biofilm formation and auto-aggregation, as well as for bladder and kidney colonization. Here, the X-ray crystal structure of the MR/P tip adhesin, MrpH, is reported. The structure has a fold not previously described and contains a transition metal center with Zn2+ coordinated by three conserved histidine residues and a ligand. Using biofilm assays, chelation, metal complementation, and site-directed mutagenesis of the three histidines, we show that an intact metal binding site occupied by zinc is essential for MR/P fimbria-mediated biofilm formation, and furthermore, that P. mirabilis biofilm formation is reversible in a zinc-dependent manner. Zinc is also required for MR/P-dependent agglutination of erythrocytes, and mutation of the metal binding site renders P. mirabilis unfit in a mouse model of UTI. The studies presented here provide important clues as to the mechanism of MR/P-mediated biofilm formation and serve as a starting point for identifying the physiological MR/P fimbrial receptor.}, } @article {pmid32780570, year = {2021}, author = {Ballal, V and Khandelwal, D and Yegneswaran, PP and Varghese, J and Al-Haj Husain, N and Özcan, M}, title = {Evaluation of Smear Layer Removal and Antimicrobial Efficacy of HybenX Against Enterococcus Faecalis Biofilm.}, journal = {The European journal of prosthodontics and restorative dentistry}, volume = {29}, number = {1}, pages = {6-13}, doi = {10.1922/EJPRD_2054Ballal08}, pmid = {32780570}, issn = {0965-7452}, mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Edetic Acid/pharmacology ; Enterococcus faecalis ; Humans ; Microscopy, Electron, Scanning ; Phenols ; Root Canal Irrigants/pharmacology ; Root Canal Preparation ; *Smear Layer ; Sodium Hypochlorite/pharmacology ; }, abstract = {To evaluate the antibacterial efficacy of HybenX, an endodontic irrigant against Enterococcus faecalis biofilm and determine its efficacy in removal of smear layer. Forty root canals were inoculated with E. faecalis for three weeks, divided into 4 groups and irrigated with: Group1: 5 ml 2.5% sodium hypochlorite; Group2: 5 ml 2% chlorhexidine gluconate; Group3: 5 ml HybenX; Group4: 5 ml distilled water (control). Dentin shavings were collected and plated on agar plates, followed by colony forming unit (CFU) determination. For smear layer removal examination, 30 single rooted teeth were instrumented and divided into 3 groups and treated with: GroupI: 5 ml of 17% EDTA; GroupII:5 ml of HybenX; and GroupIII: 5 ml of distilled water. Samples were then subjected to SEM examination. All irrigants showed a significant reduction in CFUs compared to the control group (P⟨ .001), but none compared to each other. Regarding smear layer removal in the apical third, EDTA removed smear layer more effectively than HybenX (P = .014). HybenX demonstrated good antimicrobial efficacy against E. faecalis biofilm and removed the smear layer effectively in coronal and middle third of the root canal system. HybenX can be considered as a promising irrigating agent in root canal treatment of infected teeth.}, } @article {pmid32779018, year = {2020}, author = {Verma, N and Srivastava, S and Malik, R and Yadav, JK and Goyal, P and Pandey, J}, title = {Computational investigation for modeling the protein-protein interaction of TasA(28-261)-TapA(33-253): a decisive process in biofilm formation by Bacillus subtilis.}, journal = {Journal of molecular modeling}, volume = {26}, number = {9}, pages = {226}, doi = {10.1007/s00894-020-04507-0}, pmid = {32779018}, issn = {0948-5023}, support = {SERB/YS/LS/294/2013//Science and Engineering Research Board/ ; F./2015-16/NFO-2015-17-OBC-UTT-28124//University Grants Commission/ ; }, mesh = {*Bacillus subtilis/genetics/metabolism ; Bacterial Proteins/*chemistry/genetics/metabolism ; Binding Sites ; Biofilms/growth & development ; Carrier Proteins/*chemistry ; *Models, Molecular ; Protein Binding ; Protein Conformation ; *Protein Interaction Domains and Motifs ; *Protein Interaction Mapping ; Protein Interaction Maps ; }, abstract = {Biofilms have a significant role in microbial persistence, antibiotic resistance, and chronic infections; consequently, there is a pressing need for development of novel "anti-biofilm strategies." One of the fundamental mechanisms involved in biofilm formation is protein-protein interactions of "amyloid-like proteins" (ALPs) in the extracellular matrix. Such interactions could be potential targets for development of novel anti-biofilm strategies; therefore, assessing the structural features of these interactions could be of great scientific value. Characterization of structural features the of protein-protein interaction with conventional structure biology tools including X-ray diffraction and nuclear magnetic resonance is technically challenging, expensive, and time-consuming. In contrast, modeling such interactions is time-efficient and economical, and might provide deeper understanding of structural basis of interactions. Although it is often acknowledged that molecular modeling methods have varying accuracy, their careful implementation with supplementary verification methods can provide valuable insight and directions for future studies. With this reasoning, during the present study, the protein-protein interaction of TasA(28-261)-TapA(33-253) (which is a decisive process for biofilm formation by Bacillus subtilis) was modeled using in silico approaches, viz., molecular modeling, protein-protein docking, and molecular dynamics simulations. Results obtained here identified amino acid residues present within intrinsically disordered regions of both proteins to be critical for interaction. These results were further supported with principal component analyses (PCA) and free energy landscape (FEL) analyses. Results presented here represent novel finding, and we hypothesize that amino acid residues identified during the present study could be targeted for inhibition of biofilm formation by B. subtilis.}, } @article {pmid32778558, year = {2020}, author = {Calder, JT and Christman, ND and Hawkins, JM and Erickson, DL}, title = {A Trimeric Autotransporter Enhances Biofilm Cohesiveness in Yersinia pseudotuberculosis but Not in Yersinia pestis.}, journal = {Journal of bacteriology}, volume = {202}, number = {20}, pages = {}, pmid = {32778558}, issn = {1098-5530}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Pseudogenes ; Selection, Genetic ; Siphonaptera/microbiology ; Type V Secretion Systems/metabolism ; Yersinia pestis/genetics/*growth & development ; Yersinia pseudotuberculosis/genetics/*growth & development ; Yersinia pseudotuberculosis Infections/microbiology/transmission ; }, abstract = {Cohesion of biofilms made by Yersinia pestis and Yersinia pseudotuberculosis has been attributed solely to an extracellular polysaccharide matrix encoded by the hms genes (Hms-dependent extracellular matrix [Hms-ECM]). However, mutations in the Y. pseudotuberculosis BarA/UvrY/CsrB regulatory cascade enhance biofilm stability without dramatically increasing Hms-ECM production. We found that treatment with proteinase K enzyme effectively destabilized Y. pseudotuberculosiscsrB mutant biofilms, suggesting that cell-cell interactions might be mediated by protein adhesins or extracellular matrix proteins. We identified an uncharacterized trimeric autotransporter lipoprotein (YPTB2394), repressed by csrB, which has been referred to as YadE. Biofilms made by a ΔyadE mutant strain were extremely sensitive to mechanical disruption. Overexpression of yadE in wild-type Y. pseudotuberculosis increased biofilm cohesion, similar to biofilms made by csrB or uvrY mutants. We found that the Rcs signaling cascade, which represses Hms-ECM production, activated expression of yadE The yadE gene appears to be functional in Y. pseudotuberculosis but is a pseudogene in modern Y. pestis strains. Expression of functional yadE in Y. pestis KIM6+ weakened biofilms made by these bacteria. This suggests that although the YadE autotransporter protein increases Y. pseudotuberculosis biofilm stability, it may be incompatible with the Hms-ECM production that is essential for Y. pestis biofilm production in fleas. Inactivation of yadE in Y. pestis may be another instance of selective gene loss in the evolution of flea-borne transmission by this species.IMPORTANCE The evolution of Yersinia pestis from its Y. pseudotuberculosis ancestor involved gene acquisition and gene losses, leading to differences in biofilm production. Characterizing the unique biofilm features of both species may provide better understanding of how each adapts to its specific niches. This study identifies a trimeric autotransporter, YadE, that promotes biofilm stability of Y. pseudotuberculosis but which has been inactivated in Y. pestis, perhaps because it is not compatible with the Hms polysaccharide that is crucial for biofilms inside fleas. We also reveal that the Rcs signaling cascade, which represses Hms expression, activates YadE in Y. pseudotuberculosis The ability of Y. pseudotuberculosis to use polysaccharide or YadE protein for cell-cell adhesion may help it produce biofilms in different environments.}, } @article {pmid32776210, year = {2020}, author = {Zara, G and Budroni, M and Mannazzu, I and Fancello, F and Zara, S}, title = {Yeast biofilm in food realms: occurrence and control.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {9}, pages = {134}, pmid = {32776210}, issn = {1573-0972}, support = {2017B7MMJ5_001//MIUR/ ; }, mesh = {Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Food ; *Food Microbiology ; Saccharomyces cerevisiae/drug effects ; Yeasts/drug effects/*physiology ; }, abstract = {In natural environments, microorganisms form microbial aggregates called biofilms able to adhere to a multitude of different surfaces. Yeasts make no exception to this rule, being able to form biofilms in a plethora of environmental niches. In food realms, yeast biofilms may cause major problems due to their alterative activities. In addition, yeast biofilms are tenacious structures difficult to eradicate or treat with the current arsenal of antifungal agents. Thus, much effort is being made to develop novel approaches to prevent and disrupt yeast biofilms, for example through the use of natural antimicrobials or small molecules with both inhibiting and dispersing properties. The aim of this review is to provide a synopsis of the most recent literature on yeast biofilms regarding: (i) biofilm formation mechanisms; (ii) occurrence in food and in food-related environments; and (iii) inhibition and dispersal using natural compounds, in particular.}, } @article {pmid32775870, year = {2020}, author = {Zhang, M and Liu, X and Xie, Y and Zhang, Q and Zhang, W and Jiang, X and Lin, J}, title = {Biological Safe Gold Nanoparticle-Modified Dental Aligner Prevents the Porphyromonas gingivalis Biofilm Formation.}, journal = {ACS omega}, volume = {5}, number = {30}, pages = {18685-18692}, pmid = {32775870}, issn = {2470-1343}, abstract = {Oral microbiology could directly influence overall health. Porphyromonas gingivalis (P. gingivalis) is a highly pathogenic bacterium that causes periodontitis and other related systematic diseases, including Alzheimer's disease. Orthodontic devices (e.g., invisalign aligner) is commonly used in populations with periodontitis who are also at a high risk of systematic diseases. In this study, newly explored antibacterial 4,6-diamino-2-pyrimidinethiol-modified gold nanoparticles (AuDAPT) were coated onto aligners. The coated aligners showed favorable antibacterial activity against P. gingivalis. In the presence of the coated aligner, the number of planktonic cells was decreased, and biofilm formation was prevented. This material also showed favorable biocompatibility in vivo and in vitro. This study reveals a new method for treating oral P. gingivalis by coating aligners with AuDAPT, which has typical advantages compared to other treatments for both periodontitis and related systematic diseases.}, } @article {pmid32772715, year = {2020}, author = {Sharma, G and Dang, S and K, A and Kalia, M and Gabrani, R}, title = {Synergistic antibacterial and anti-biofilm activity of nisin like bacteriocin with curcumin and cinnamaldehyde against ESBL and MBL producing clinical strains.}, journal = {Biofouling}, volume = {36}, number = {6}, pages = {710-724}, doi = {10.1080/08927014.2020.1804553}, pmid = {32772715}, issn = {1029-2454}, mesh = {Acrolein/analogs & derivatives ; Animals ; *Anti-Bacterial Agents/pharmacology ; *Bacteriocins ; *Biofilms ; Chlorocebus aethiops ; *Curcumin/pharmacology ; Microbial Sensitivity Tests ; *Nisin/pharmacology ; Vero Cells ; beta-Lactamases ; }, abstract = {Bacteriocins are small peptides that can inhibit the growth of a diverse range of microbes. There is a need to identify bacteriocins that are effective against biofilms of resistant clinical strains. The present study focussed on the efficacy of purified nisin like bacteriocin-GAM217 against extended spectrum β-lactamase (ESBL) and metallo-beta-lactamase (MBL) producing clinical strains. Bacteriocin-GAM217 when combined with curcumin and cinnamaldehyde, synergistically enhanced antibacterial activity against planktonic and biofilm cultures of Staphylococcus epidermidis and Escherichia coli. Bacteriocin-GAM217 and phytochemical combinations inhibited biofilm formation by >80%, and disrupted the biofilm for selected ESBL and MBL producing clinical strains. The anti-adhesion assay showed that these combinatorial compounds significantly lowered the attachment of bacteria to Vero cells and that they elicited membrane permeability and rapid killing as viewed by confocal microscopy. This study demonstrates that bacteriocin-GAM217 in combination with phytochemicals can be a potential anti-biofilm agent and thus has potential for biomedical applications.}, } @article {pmid32771657, year = {2020}, author = {Huang, ZX and Yu, JH and Xu, XJ and Xu, XF and Zeng, T and Lin, J and Chen, WM}, title = {Cajaninstilbene acid analogues as novel quorum sensing and biofilm inhibitors of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {148}, number = {}, pages = {104414}, doi = {10.1016/j.micpath.2020.104414}, pmid = {32771657}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Pseudomonas aeruginosa/*drug effects ; *Quorum Sensing/drug effects ; Salicylates/*pharmacology ; Stilbenes/*pharmacology ; Virulence Factors ; }, abstract = {Biofilm formation and virulence factor secretion in opportunistic pathogen Pseudomonas aeruginosa are essential for establishment of chronic and recurrent infection, which are regulated by quorum sensing (QS) system. In this study, a set of cajaninstilbene acid analogues were designed and synthesized, and their abilities to inhibit QS and biofilm formation were investigated. Among all the compounds, compounds 3g, 3m and 3o showed potent anti-biofilm activity, especially 3o exhibited promising biofilm inhibitory activity with biofilm inhibition ratio of 49.50 ± 1.35% at 50 μM. Three lacZ reporter strains were constructed to identify the effects of compound 3o on different QS systems. Compound 3o showed the suppression on the expression of lasB-lacZ and pqsA-lacZ as well as on the production of their corresponding virulence factors. Therefore, compound 3o is expected to be generated as a lead compound with inhibition of biofilm formation and QS of Pseudomonas aeruginosa.}, } @article {pmid32771591, year = {2020}, author = {Bhadila, G and Filemban, H and Wang, X and Melo, MAS and Arola, DD and Tay, FR and Oates, TW and Weir, MD and Sun, J and Xu, HHK}, title = {Bioactive low-shrinkage-stress nanocomposite suppresses S. mutans biofilm and preserves tooth dentin hardness.}, journal = {Acta biomaterialia}, volume = {114}, number = {}, pages = {146-157}, doi = {10.1016/j.actbio.2020.07.057}, pmid = {32771591}, issn = {1878-7568}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Calcium Phosphates ; *Dental Caries/drug therapy/prevention & control ; Dentin ; Hardness ; Humans ; Methacrylates/pharmacology ; *Nanocomposites ; Streptococcus mutans ; }, abstract = {Recurrent dental caries is one of the main reasons for resin composite restoration failures. This study aimed to: (1) develop a bioactive, low-shrinkage-stress, antibacterial and remineralizing composite and evaluate the sustainability of its antibacterial effect against Streptococcus mutans (S. mutans) biofilms; and (2) evaluate the remineralization and cariostatic potential of the composite containing nanoparticles of amorphous calcium phosphate (NACP) and dimethylaminohexadecyl methacrylate (DMAHDM), using dentin hardness measurement and a biofilm-induced recurrent caries model. The antibacterial and remineralizing low-shrinkage-stress composite consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE), 3% DMAHDM and 20% NACP. S. mutans biofilm was used to evaluate antibiofilm activity, before and after 3 months of composite aging in acidic solution. Human dentin was used to develop a recurrent caries biofilm-model. Adding DMAHDM and NACP into low shrinkage-stress composite did not compromise the flexural strength. The low-shrinkage-stress composite with DMAHDM achieved substantial reductions in biofilm colony-forming units (CFU), lactic acid production, and biofilm biomass (p < 0.05). The low-shrinkage-stress DMAHDM+NACP composite exhibited no significant difference in antibacterial performance before and after 3 months of aging, demonstrating long-term antibacterial activity. Under S. mutans biofilm acidic attack, dentin hardness (GPa) was 0.24 ± 0.04 for commercial control, and 0.23 ± 0.03 for experimental control, but significantly higher at 0.34 ± 0.03 for DMAHDM+NACP group (p < 0.05). At an instrumental compliance of 0.33 μm/N, the polymerization shrinkage stress of the new composite was 36% lower than that of a traditional composite (p < 0.05). The triple strategy of antibacterial, remineralization and lower shrinkage-stress has great potential to inhibit recurrent caries and increase restoration longevity. Statement of Significance Polymerization shrinkage stress, masticatory load over time as well as biochemical degradation can lead to marginal failure and secondary caries. The present study developed a new low-shrinkage-stress, antibacterial and remineralizing dental nanocomposite. Polymerization shrinkage stress was greatly reduced, biofilm acid production was inhibited, and tooth dentin mineral and hardness were preserved. The antibacterial composite possessed a long-lasting antibiofilm effect against cariogenic bacteria S. mutans. The new bioactive nanocomposite has the potential to suppress recurrent caries at the restoration margins, protects tooth structures, and increases restoration longevity.}, } @article {pmid32769186, year = {2020}, author = {Griewisch, KF and Pierce, JG and Elfenbein, JR}, title = {Genetic Determinants of Salmonella Resistance to the Biofilm-Inhibitory Effects of a Synthetic 4-Oxazolidinone Analog.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {20}, pages = {}, pmid = {32769186}, issn = {1098-5336}, support = {K08 AI108794/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial/*genetics ; Oxazolidinones/*pharmacology ; Salmonella typhimurium/drug effects/*genetics ; }, abstract = {Biofilms formed by Salmonella enterica are a frequent source of food supply contamination. Since biofilms are inherently resistant to disinfection, new agents capable of preventing biofilm formation are needed. Synthetic analogs of 4-oxazolidinone containing natural products have shown promise as antibiofilm compounds against Gram-positive bacteria. The purpose of our study was 2-fold: to establish the antibiofilm effects and mechanism of action of a synthetic 4-oxazolidinone analog (JJM-ox-3-70) and to establish mechanisms of resistance to this compound in Salmonella enterica serovar Typhimurium (S Typhimurium). JJM-ox-3-70 inhibited biofilm formation but had no effect on cell growth. The antibiofilm effects were linked to disruption of curli fimbriae and flagellar gene expression and alteration in swimming motility, suggesting an effect on multiple cellular processes. Using a 2-step screening approach of defined multigene and single-gene deletion mutant libraries, we identified 3 mutants that produced less biofilm in the presence of JJM-ox-3-70 than the isogenic WT, with phenotypes reversed by complementation in trans Genes responsible for S Typhimurium resistance to the compound included acrB, a component of the major drug efflux pump AcrAB-TolC, and two genes of unknown function (STM0437 and STM1292). The results of this study suggest that JJM-ox-3-70 inhibits biofilm formation by indirect inhibition of extracellular matrix production that may be linked to disruption of flagellar motility. Further work is needed to establish the role of the newly characterized genes as potential mechanisms of biofilm intrinsic antimicrobial resistance.IMPORTANCE Biofilms are resistant to killing by disinfectants and antimicrobials. S. enterica biofilms facilitate long-term host colonization and persistence in food processing environments. Synthetic analogs of 4-oxazolidinone natural products show promise as antibiofilm agents. Here, we show that a synthetic 4-oxazolidinone analog inhibits Salmonella biofilm through effects on both motility and biofilm matrix gene expression. Furthermore, we identify three genes that promote Salmonella resistance to the antibiofilm effects of the compound. This work provides insight into the mechanism of antibiofilm effects of a synthetic 4-oxazolidinone analog in Gram-negative bacteria and demonstrates new mechanisms of intrinsic antimicrobial resistance in Salmonella biofilms.}, } @article {pmid32768224, year = {2020}, author = {Lu, J and Li, L and Pan, F and Zuo, G and Yu, D and Liu, R and Fan, H and Ma, Z}, title = {PagC is involved in salmonella pullorum OMVs production and affects biofilm production.}, journal = {Veterinary microbiology}, volume = {247}, number = {}, pages = {108778}, doi = {10.1016/j.vetmic.2020.108778}, pmid = {32768224}, issn = {1873-2542}, mesh = {Animals ; Bacterial Outer Membrane/*physiology ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; Cecum/microbiology ; Chickens/microbiology ; Gene Deletion ; Intestines/microbiology ; Salmonella enterica/classification/*genetics/physiology ; Specific Pathogen-Free Organisms ; }, abstract = {The pagC gene is ubiquitously distributed in Salmonella, but there is limited information regarding its function. Pullorum disease (PD) is a septicemic disease caused by Salmonella Pullorum, which also harbors the pagC gene. In this study, we constructed an S. Pullorum pagC gene deletion strain and its complemented strain. First, we confirmed that the pagC gene does not participate in bacterial growth regulation or environmental pH adaptation. Interestingly, the results of subsequent analyses indicated that the pagC gene defect led to increased bacterial colonization in the intestine (especially in the cecum) and increased biofilm formation, while the number of outer-membrane vesicles (OMVs) in the bacterial culture decreased. Purified OMVs were able to reduce S. Pullorum biofilm formation in vitro. In addition, the results of a mass spectrometry analysis of purified OMVs indicated that some enzymes harbored by OMVs may be involved in biofilm degradation. Based on these results, we conclude that deletion of the pagC gene leads to reduced S. Pullorum OMVs production, which subsequently promotes biofilm stability, increases bacterial colonization in the intestine, and potentially inhibits the switch from sessile to planktonic growth.}, } @article {pmid32768206, year = {2020}, author = {Liu, Y and Gong, Q and Qian, X and Li, D and Zeng, H and Li, Y and Xue, F and Ren, J and Zhu Ge, X and Tang, F and Dai, J}, title = {Prophage phiv205-1 facilitates biofilm formation and pathogenicity of avian pathogenic Escherichia coli strain DE205B.}, journal = {Veterinary microbiology}, volume = {247}, number = {}, pages = {108752}, doi = {10.1016/j.vetmic.2020.108752}, pmid = {32768206}, issn = {1873-2542}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Cell Line ; Chickens ; Ducks/microbiology ; Escherichia coli/genetics/*pathogenicity/virology ; Escherichia coli Infections/microbiology/*veterinary ; Fibroblasts/microbiology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Prophages/*physiology ; Virulence ; }, abstract = {Avian colibacillosis caused by avian pathogenic Escherichia coli (APEC) causes significant economic losses to the poultry industry worldwide and is also a leading potential threat to human health. Bacteriophages integrate into the host bacterial chromosome, and are an important source of genetic variation and have a major impact on bacterial evolution. Previously, we predicted prophage phiv205-1 in APEC strain DE205B. Here, to determine the function of prophage phiv205-1, we constructed the prophage deletion mutant DE205BΔphiv205-1. Compared with the wild-type (WT) APEC strain DE205B, the adherence and invasive abilities of DE205BΔphiv205-1 were reduced by 41.88 %(P < 0.05). Further, the mutant strain had 52.38 % reduced biofilm formation compared with the WT strain (P < 0.001). Chick challenge showed that the median lethal dose (LD50) of the mutant strain and WT strain was 3.13 × 10[5] colony-forming units (CFU) and 3.86 × 10[4] CFU, respectively, indicating that the mutant strain had decreased virulence compared with the WT strain. Furthermore, in vivo studies showed that, compared with the WT strain, DE205BΔphiv205-1 bacterial loads were reduced by 1.6-fold (P < 0.05) and 4.8-fold (P < 0.001) in the lungs and brains, respectively, of the infected chicks. In conclusion, the prophage phiv205-1 contributes to the virulence of APEC strain DE205B by facilitating the adherence, biofilm formation, and colonization abilities of its host strain.}, } @article {pmid32767025, year = {2020}, author = {Song, YM and Zhou, HY and Wu, Y and Wang, J and Liu, Q and Mei, YF}, title = {In Vitro Evaluation of the Antibacterial Properties of Tea Tree Oil on Planktonic and Biofilm-Forming Streptococcus mutans.}, journal = {AAPS PharmSciTech}, volume = {21}, number = {6}, pages = {227}, doi = {10.1208/s12249-020-01753-6}, pmid = {32767025}, issn = {1530-9932}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Dental Caries/microbiology ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Streptococcus mutans/drug effects ; Tea Tree Oil/*pharmacology ; }, abstract = {Streptococcus mutans (S. mutans) is the principal etiologic agent in the occurrence of human dental caries and the formation of biofilms on the surface of teeth. Tea tree oil (TTO) has been demonstrated to exhibit a wide range of pharmacological actions that can effectively inhibit the activity of bacteria. In this context, we evaluated the in vitro antimicrobial effects of TTO on S. mutans both during planktonic growth and in biofilms compared with 0.2% CHX. We determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the microdilution method, the bacteriostatic rate using an MTT assay, and the antimicrobial time using a time-kill assay. Then, we explored the effects of TTO on acid production and cell integrity. Furthermore, the effects of TTO on the biomass and bacterial activity of S. mutans biofilms were studied. Finally, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to investigate the structure and activity of biofilms. The MIC and MBC values were 0.125% and 0.25%, and the bacterial inhibition rate was concentration dependent. TTO can effectively inhibit bacterial acid production and destroy the integrity of the cell membrane. Electron micrographs revealed a reduction in bacterial aggregation, inhibited biofilm formation, and reduced biofilm thickness. The effect of TTO was the same as that of 0.2% CHX at a specific concentration. In summary, we suggest that TTO is a potential anticariogenic agent that can be used against S. mutans.}, } @article {pmid32765439, year = {2020}, author = {Xie, X and Liu, X and Li, Y and Luo, L and Yuan, W and Chen, B and Liang, G and Shen, R and Li, H and Huang, S and Duan, C}, title = {Advanced Glycation End Products Enhance Biofilm Formation by Promoting Extracellular DNA Release Through sigB Upregulation in Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1479}, pmid = {32765439}, issn = {1664-302X}, abstract = {Bacterial biofilms do serious harm to the diabetic foot ulcer (DFU) because they play a crucial role in infection invasion and spread. Staphylococcus aureus, the predominant Gram-positive bacteria in diabetic foot infection (DFI), is often associated with colonization and biofilm formation. Through biofilm formation tests in vitro, we observed that S. aureus bacteria isolated from DFU wounds were more prone to form biofilms than those from non-diabetic patients, while there was no difference in blood sugar between the biofilm (+) diabetics (DB+) and biofilm (-) diabetics (DB-). Furthermore, we found that advanced glycation end products (AGEs) promoted the biofilm formation of S. aureus in clinical isolates and laboratory strains in vitro, including a methicillin-resistant strain. Analysis of biofilm components demonstrated that the biofilms formed mainly by increasing extracellular DNA (eDNA) release; remarkably, the S. aureus global regulator sigB was upregulated, and its downstream factor lrgA was downregulated after AGE treatments. Mechanism studies using a sigB-deleted mutant (Newman-ΔsigB) confirmed that AGEs decreased expression of lrgA via induction of sigB, which is responsible for eDNA release and is a required component for S. aureus biofilm development. In conclusion, the present study suggests that AGEs promote S. aureus biofilm formation via an eDNA-dependent pathway by regulating sigB. The data generated by this study will provide experimental proof and theoretical support to improve DFU infection healing.}, } @article {pmid32765020, year = {2020}, author = {Sharifian, P and Yaslianifard, S and Fallah, P and Aynesazi, S and Bakhtiyari, M and Mohammadzadeh, M}, title = {Investigating the Effect of Nano-Curcumin on the Expression of Biofilm Regulatory Genes of Pseudomonas aeruginosa.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {2477-2484}, pmid = {32765020}, issn = {1178-6973}, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen that causes serious nosocomial infections, especially in immunodeficient patients and cystic fibrosis, cancer, and burned individuals. The biofilm that plays an important role in the virulence of P. aeruginosa is under the regulation of quorum sensing and two-component regulatory systems of bacteria. Curcumin, an active phenolic extract of turmeric has shown an inhibitory effect on the biofilm formation of some pathogenic bacteria. Thus, the present study aims to evaluate the effect of Nano-Curcumin on the expression of major regulatory genes involved in biofilm formation of P. aeruginosa.

MATERIALS AND METHODS: The biofilm formation of P. aeruginosa ATCC 10145 was assessed in the presence of 15, 20, and 25 µg/mL concentrations of Nano-Curcumin using the microplate titer method. The effect of Nano-Curcumin on the expression level of regulatory genes were determined by relative reverse transcriptase-realtime PCR.

RESULTS: In the absence of Nano-Curcumin, P. aeruginosa strain ATCC 10145 strongly produced biofilm (3+) and in the presence of 15 and 20 µg/mL, biofilm formation was reduced to moderate (2+) and weak biofilm producer (1+), respectively. Nano-Curcumin at a concentration of 25µg/mL inhibited biofilm formation in P. aeruginosa. The expression of regulatory genes was not affected by biofilm inhibitory concentrations of Nano-Curcumin.

CONCLUSION: The antibiofilm mechanism of Curcumin is not related to the downregulation of regulatory systems of P. aeruginosa and probably it prevents the formation of a complete biofilm structure.}, } @article {pmid32763746, year = {2020}, author = {Carneiro, RB and Mukaeda, CM and Sabatini, CA and Santos-Neto, ÁJ and Zaiat, M}, title = {Influence of organic loading rate on ciprofloxacin and sulfamethoxazole biodegradation in anaerobic fixed bed biofilm reactors.}, journal = {Journal of environmental management}, volume = {273}, number = {}, pages = {111170}, doi = {10.1016/j.jenvman.2020.111170}, pmid = {32763746}, issn = {1095-8630}, mesh = {Anaerobiosis ; Bacteria, Anaerobic ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; *Ciprofloxacin ; Sewage ; *Sulfamethoxazole ; Waste Disposal, Fluid ; }, abstract = {Antibiotic compounds, notably sulfamethoxazole (SMX) and ciprofloxacin (CIP), are ubiquitous emerging contaminants (ECs), which are often found in domestic sewage. They are associated with the development of antimicrobial resistance. Operational parameters, e.g. organic loading rate (OLR), hydraulic retention time (HRT) and sludge retention time, may influence EC biodegradation in wastewater treatment plants. This study assessed the impact of the OLR variation on the biodegradation of CIP and SMX, applying two configurations of anaerobic fixed bed reactors: anaerobic packed bed biofilm reactor (APBBR) and anaerobic structured bed biofilm reactor (ASBBR). A significant reduction in the biodegradation of SMX (APBBR: 93-69%; ASBBR: 94-81%) and CIP (APBBR: 85-66%; ASBBR: 85-64%) was observed increasing OLR from 0.6 to 2.0 kgCOD m[-3] d[-1]. The decrease in the HRT from 12 to 4 h resulted in higher liquid-phase mass transfer coefficient (APBBR: ks from 0.01 to 0.05 cm h[-1]; ASBBR: ks from 0.07 to 0.24 cm h[-1]), but this was not enough to overcome the decrease in the antibiotic-biomass contact time on biofilm, thus reducing the bioreactors' performance. The ASBBR favored biomethane production (from 7 to 17 mLCH4 g[-1]VSS L[-1] d[-1]) and biodegradation kinetics (kbio from 1.7 to 4.2 and for SMX and from 2.1 to 4.8 L g[-1]VSS d[-1] for CIP) due to the higher relative abundance of the archaea community in the biofilm and the lower liquid-phase mass transfer resistance in the structured bed. CIP and SMX cometabolic biodegradation was associated to the hydrogenotrophic methanogenesis (mainly Methanobacterium genus) in co-culture with fermentative bacteria (notably the genera Clostridium, Bacillus, Lactivibrio, Syntrophobacter and Syntrophorhabdus). The anaerobic fixed bed biofilm reactors proved to be highly efficient in biodegrading the antibiotics, preventing them from spreading to the environment.}, } @article {pmid32763572, year = {2021}, author = {Abbasi, M and Aminian-Dehkordi, J and Mousavi, SM}, title = {A novel computational simulation approach to study biofilm significance in a packed-bed biooxidation reactor.}, journal = {Chemosphere}, volume = {262}, number = {}, pages = {127680}, doi = {10.1016/j.chemosphere.2020.127680}, pmid = {32763572}, issn = {1879-1298}, mesh = {Bacteria/*metabolism ; Beds ; Biofilms ; *Bioreactors ; Computer Simulation ; }, abstract = {Fe (II) biooxidation has recently gained significant interest. It plays a key role in a number of environmental and industrial processes such as bioleaching, acid mine drainage treatment, desulphurization of sour gases, and coal desulphurization. In this work, a three-dimensional CFD model for gas-liquid flow in a lab-scale packed-bed biooxidation reactor is used. The reactor is randomly packed with spherical particles, and the particles are covered with Leptospirillum ferrooxidans biofilm for Fe (II) biooxidation. A modified Jodrey-Tory algorithm is used to generate random packing with actual porosity of 0.42, and biofilm layer with constant thickness is considered over the particles. A simplified Eulerian-Eulerian model is used to obtain detailed flow field. The concentration profile in the reactor and the conversion of Fe (II) from the present simulations are obtained and validated using experimental data reported in the literature. The results of the study indicate that about three-quarters of the conversion occurs in the upper half of the reactor and Fe (II) concentration on the biofilm surface at the lower quarter of the reactor does not exceed 5 mM (The inlet concentration is 89.6 mM). The findings reveal that rate-limiting phenomena may vary in different parts of the reactor. The results obtained through the simulations represent advantages for the design and optimization of packed-bed biofilm reactors.}, } @article {pmid32763530, year = {2020}, author = {Gerbersdorf, SU and Koca, K and de Beer, D and Chennu, A and Noss, C and Risse-Buhl, U and Weitere, M and Eiff, O and Wagner, M and Aberle, J and Schweikert, M and Terheiden, K}, title = {Exploring flow-biofilm-sediment interactions: Assessment of current status and future challenges.}, journal = {Water research}, volume = {185}, number = {}, pages = {116182}, doi = {10.1016/j.watres.2020.116182}, pmid = {32763530}, issn = {1879-2448}, mesh = {Biofilms ; Ecosystem ; *Geologic Sediments ; Water ; *Water Pollutants, Chemical/analysis ; }, abstract = {Biofilm activities and their interactions with physical, chemical and biological processes are of great importance for a variety of ecosystem functions, impacting hydrogeomorphology, water quality and aquatic ecosystem health. Effective management of water bodies requires advancing our understanding of how flow influences biofilm-bound sediment and ecosystem processes and vice-versa. However, research on this triangle of flow-biofilm-sediment is still at its infancy. In this Review, we summarize the current state of the art and methodological approaches in the flow-biofilm-sediment research with an emphasis on biostabilization and fine sediment dynamics mainly in the benthic zone of lotic and lentic environments. Example studies of this three-way interaction across a range of spatial scales from cell (nm - µm) to patch scale (mm - dm) are highlighted in view of the urgent need for interdisciplinary approaches. As a contribution to the review, we combine a literature survey with results of a pilot experiment that was conducted in the framework of a joint workshop to explore the feasibility of asking interdisciplinary questions. Further, within this workshop various observation and measuring approaches were tested and the quality of the achieved results was evaluated individually and in combination. Accordingly, the paper concludes by highlighting the following research challenges to be considered within the forthcoming years in the triangle of flow-biofilm-sediment: i) Establish a collaborative work among hydraulic and sedimentation engineers as well as ecologists to study mutual goals with appropriate methods. Perform realistic experimental studies to test hypotheses on flow-biofilm-sediment interactions as well as structural and mechanical characteristics of the bed. ii) Consider spatially varying characteristics of flow at the sediment-water interface. Utilize combinations of microsensors and non-intrusive optical methods, such as particle image velocimetry and laser scanner to elucidate the mechanism behind biofilm growth as well as mass and momentum flux exchanges between biofilm and water. Use molecular approaches (DNA, pigments, staining, microscopy) for sophisticated community analyses. Link varying flow regimes to microbial communities (and processes) and fine sediment properties to explore the role of key microbial players and functions in enhancing sediment stability (biostabilization). iii) Link laboratory-scale observations to larger scales relevant for management of water bodies. Conduct field experiments to better understand the complex effects of variable flow and sediment regimes on biostabilization. Employ scalable and informative observation techniques (e.g., hyperspectral imaging, particle tracking) that can support predictions on the functional aspects, such as metabolic activity, bed stability, nutrient fluxes under variable regimes of flow-biofilm-sediment.}, } @article {pmid32762802, year = {2020}, author = {Czieborowski, M and Hübenthal, A and Poehlein, A and Vogt, I and Philipp, B}, title = {Genetic and physiological analysis of biofilm formation on different plastic surfaces by Sphingomonas sp. strain S2M10 reveals an essential function of sphingan biosynthesis.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {10}, pages = {918-935}, doi = {10.1099/mic.0.000961}, pmid = {32762802}, issn = {1465-2080}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Carbon/analysis/metabolism ; DNA Transposable Elements/genetics ; Flagella/genetics/metabolism ; Histidine Kinase/genetics/metabolism ; Mutation ; Plastics/chemistry/*metabolism ; Polysaccharides, Bacterial/*biosynthesis/genetics ; Signal Transduction ; Sphingomonas/genetics/isolation & purification/metabolism/*physiology ; Transcription, Genetic ; Water Microbiology ; }, abstract = {Alphaproteobacteria belonging to the group of the sphingomonads are frequently found in biofilms colonizing pure-water systems, where they cause technical and hygienic problems. In this study, physiological properties of sphingomonads for biofilm formation on plastic surfaces were analysed. Sphingomonas sp. strain S2M10 was isolated from a used water-filtration membrane and submitted to transposon mutagenesis for isolating mutants with altered biofilm formation. Mutants showing strongly decreased biofilm formation carried transposon insertions in genes for the biosynthesis of the polysaccharide sphingan and for flagellar motility. Flagella-mediated attachment was apparently important for biofilm formation on plastic materials of intermediate hydrophobicity, while a mutant with defect in spnB, encoding the first enzyme in sphingan biosynthesis, showed no biofilm formation on all tested materials. Sphingan-dependent biofilm formation was induced in the presence of specific carbon sources while it was not induced in complex medium with yeast extract and tryptone. The regulation of sphingan-based biofilm formation was investigated by interfering with the CckA/ChpT/CtrA phosphorelay, a central signal-transduction pathway in most Alphaproteobacteria. Construction and ectopic expression of a kinase-deficient histidine kinase CckA caused cell elongation and massive sphingan-dependent cell aggregation. In addition, it caused increased activity of the promotor of spnB. In conclusion, these results indicate that sphingan-based biofilm formation by sphingomonads might be triggered by specific carbon sources under prototrophic conditions resembling a milieu that often prevails in pure-water systems.}, } @article {pmid32762195, year = {2020}, author = {Ignatova, NI and Alexandrova, NA and Zaslavskaya, MI and Abramycheva, DV}, title = {[Evaluation of the influence of culturing on the intensity of biofilm formation by Klebsiella pneumoniae strains.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {65}, number = {8}, pages = {512-515}, doi = {10.18821/0869-2084-2020-65-8-512-515}, pmid = {32762195}, issn = {0869-2084}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Humans ; *Klebsiella Infections ; *Klebsiella pneumoniae ; }, abstract = {Due to the prevalence of biofilm infections caused by Klebsiella pneumoniae, in laboratory diagnostic practice it has a great importance to obtain a standard model of Klebsiella biofilm for evaluating the bactericidal effect and effectiveness of antimicrobial drugs. Describes the method of Klebsiella biofilms formation in vitro. The intensity of biofilm formation was evaluated by the ability of bacteria to bind the crystal violet. The degree of film formation was measured by optical density. The presence of an intercellular matrix was confirmed by staining of Congo-red solution followed by light microscopy. The effect of exogenous and endogenous factors on biofilm formation by K. pneumoniae strains was investigated. The influence of the nutrient composition, the age of the culture («daily», «weekly»), the presence of oxygen and the temperature conditions were studied. The nutrient composition of the medium significantly influenced on biofilm formation of K. pneumoniae: DMEM stimulated biofilm formation in most strains in vitro compared to TSB. The age of the culture (daily, weekly) did not significantly affect the biofilm formation of Klebsiella. At the same time, the temperature of culturing and the presence of oxygen can both stimulate and inhibit biofilm formation, depending on the strain under study. Most strains of Klebsiella better form a biofilm under aerobic conditions at 37º C.}, } @article {pmid32760962, year = {2020}, author = {Kreis, CT and Sullan, RMA}, title = {Interfacial nanomechanical heterogeneity of the E. coli biofilm matrix.}, journal = {Nanoscale}, volume = {12}, number = {32}, pages = {16819-16830}, doi = {10.1039/d0nr03646c}, pmid = {32760962}, issn = {2040-3372}, mesh = {*Anti-Infective Agents ; Biofilms ; Escherichia coli ; *Extracellular Polymeric Substance Matrix ; Microscopy, Atomic Force ; }, abstract = {The interface between bacterial biofilms and their environment plays a vital role in the recalcitrance of biofilms to biological, chemical, and mechanical threats. Nonetheless, we know little about the physical parameters that dictate the interfacial morphology and nanomechanics of biofilms. Here, we present a robust, reproducible, and quantitative platform based on atomic force microscopy (AFM) that allows for correlated high-resolution imaging of the morphology and nanomechanical properties of an intact E. coli biofilm-under physiological conditions. We developed analysis algorithms based on linearized Hertzian contact mechanics to discriminate, at the nanoscale, the elasticity of the extracellular polymeric substances (EPS) from bacteria within the biofilm. We were able to identify two distinct EPS populations with approximately 10-fold difference in their elastic properties. A correlation between EPS' elasticity and morphology points to different functions of the EPS populations within a mature E. coli biofilm. Thus, beyond high-resolution nanomechanical maps of a complex biological sample, we provide direct evidence of nanoscale heterogeneities at the biofilm interface. As interactions between biofilms and various antimicrobial agents occur at the nanoscale, understanding the physico-mechanical properties at the interface-with nanometer resolution-is imperative in devising targeted strategies against bacterial biofilms. We anticipate that in conjunction with other existing approaches, our quantitative imaging platform will provide mechanistic insights into the action and effectiveness of antimicrobials and antibiofilm agents.}, } @article {pmid32759754, year = {2020}, author = {Srivastava, N and Ellepola, K and Venkiteswaran, N and Chai, LYA and Ohshima, T and Seneviratne, CJ}, title = {Lactobacillus Plantarum 108 Inhibits Streptococcus mutans and Candida albicans Mixed-Species Biofilm Formation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32759754}, issn = {2079-6382}, support = {2014/079/STB/B2B FY14/06 and 1455/2016, respectively//NUHSRO and NMRC/CIRG/ ; }, abstract = {Streptococcus mutans is the principal biofilm forming oral pathogen associated with dental caries. Studies have shown that Candida albicans, a commensal oral fungus is capable of forming pathogenic mixed-species biofilms with S. mutans. The treatment of bacterial and fungal infections using conventional antimicrobial agents has become challenging due to the antimicrobial resistance of the biofilm mode of growth. The present study aimed to evaluate the efficacy of secretory components of Lactobacillus plantarum 108, a potentially promising probiotic strain, against S. mutans and C. albicans single and mixed-species biofilms. L. plantarum 108 supernatant inhibited S. mutans and C. albicans single-species biofilms as shown by XTT reduction assay, crystal violet assay, and colony forming units counting. The probiotic supernatant significantly inhibited the S. mutans and C. albicans mixed-species biofilm formation. The pre-formed mixed-species biofilms were also successfully reduced. Confocal microscopy showed poorly developed biofilm architecture in the probiotic supernatant treated biofilms. Moreover, the expression of S. mutans genes associated with glucosyltransferase activity and C. albicans hyphal specific genes (HWP1, ALS1 and ALS3) were down-regulated in the presence of the probiotic supernatant. Altogether, the data demonstrated the capacity of L. plantarum 108 supernatant to inhibit the S. mutans and C. albicans mixed-species biofilms. Herein, we provide a new insight on the potential of probiotic-based strategies to prevent bacterial-fungal mixed-species biofilms associated with dental caries.}, } @article {pmid32759753, year = {2020}, author = {Vach, K and Al-Ahmad, A and Anderson, A and Woelber, JP and Karygianni, L and Wittmer, A and Hellwig, E}, title = {Analysing the Relationship between Nutrition and the Microbial Composition of the Oral Biofilm-Insights from the Analysis of Individual Variability.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32759753}, issn = {2079-6382}, abstract = {The influence of a change in nutrition on the oral microbiota are discussed in literature, but usually only changes of population mean values are reported. This paper introduces simple methods to also analyse and report the variability of patients' reactions considering data from the culture analysis of oral biofilm. The framework was illustrated by an experimental study exposing eleven participants to different nutrition schemes in five consecutive phases. Substantial inter-individual variations in the individual reactions were observed. A new coherence index made it possible to identify 14 instances where the direction of individual changes tended to coincide with the direction of the mean change with more than 95% probability. The heterogeneity in variability across different bacteria species was limited. This allowed us to develop recommendations for sample sizes in future studies. For studies measuring the concentration change of bacteria as a reaction to nutrition change, the use of replications and analysis of the variability is recommended. In order to detect moderate effects of a change in nutrition on the concentration of single bacterial taxa, 30 participants with three repetitions are often adequate. Insights into the relationship between nutrition and the microbial composition can be helpful for the development of dietary habits that promote the establishment of a healthy microbial flora and can therefore prevent the initiation of oral diseases such as caries and periodontitis.}, } @article {pmid32759748, year = {2020}, author = {Balaure, PC and Grumezescu, AM}, title = {Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part II: Active, Combined Active and Passive, and Smart Bacteria-Responsive Antibiofilm Nanocoatings.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {10}, number = {8}, pages = {}, pmid = {32759748}, issn = {2079-4991}, abstract = {The second part of our review describing new achievements in the field of biofilm prevention and control, begins with a discussion of the active antibiofilm nanocoatings. We present the antibiofilm strategies based on antimicrobial agents that kill pathogens, inhibit their growth, or disrupt the molecular mechanisms of biofilm-associated increase in resistance and tolerance. These agents of various chemical structures act through a plethora of mechanisms targeting vital bacterial metabolic pathways or cellular structures like cell walls and cell membranes or interfering with the processes that underlie different stages of the biofilm life cycle. We illustrate the latter action mechanisms through inhibitors of the quorum sensing signaling pathway, inhibitors of cyclic-di-GMP signaling system, inhibitors of (p)ppGpp regulated stringent response, and disruptors of the biofilm extracellular polymeric substances matrix (EPS). Both main types of active antibiofilm surfaces, namely non-leaching or contact killing systems, which rely on the covalent immobilization of the antimicrobial agent on the surface of the coatings and drug-releasing systems in which the antimicrobial agent is physically entrapped in the bulk of the coatings, are presented, highlighting the advantages of each coating type in terms of antibacterial efficacy, biocompatibility, selective toxicity, as well as drawbacks and limitations. Developments regarding combined strategies that join in a unique platform, both passive and active elements are not omitted. In such platforms with dual functionality, passive and active strategies can be applied either simultaneously or sequentially. We especially emphasize those systems that can be reversely and repeatedly switched between the non-fouling status and the bacterial killing status, thereby allowing several bacteria-killing/surface regeneration cycles to be performed without significant loss of the initial bactericidal activity. Eventually, smart antibiofilm coatings that release their antimicrobial payload on demand, being activated by various triggers such as changes in local pH, temperature, or enzymatic triggers, are presented. Special emphasis is given to the most recent trend in the field of anti-infective surfaces, specifically smart self-defensive surfaces for which activation and switch to the bactericidal status are triggered by the pathogens themselves.}, } @article {pmid32758834, year = {2020}, author = {Guo, K and Wu, N and Manolaki, P and Baattrup-Pedersen, A and Riis, T}, title = {Short-period hydrological regimes override physico-chemical variables in shaping stream diatom traits, biomass and biofilm community functions.}, journal = {The Science of the total environment}, volume = {743}, number = {}, pages = {140720}, doi = {10.1016/j.scitotenv.2020.140720}, pmid = {32758834}, issn = {1879-1026}, mesh = {Biofilms ; Biomass ; Chlorophyll A ; *Diatoms ; Ecosystem ; Hydrology ; *Rivers ; }, abstract = {Despite increasing interest in hydrological effects on riverine ecosystems, few studies have documented the impact of hydrology on biofilm community functions, and those existing have typically focused on annual-based hydrological indices. In this study, we conducted monthly samplings during a year in five lowland streams with different flow regimes and investigated the impacts of hydrological conditions and physico-chemical variables on the trait composition of diatoms growing on artificial substrates, biomass (chlorophyll a and ash free dry weight), and biofilm community functions (biochemical processes, i.e., biofilm metabolism and nutrient uptake rates measured in the laboratory). Instead of the commonly used annual-based hydrological indices, we calculated indices for shorter periods (14 and ~28 days) of the hydrological regimes. Results of species-based variation partitioning showed that short-period hydrological indices (10.10 ± 7.18%) contributed more to explain species distribution than physico-chemical variables (5.90 ± 3.83%), indicating the dominant role of hydrology in structuring the diatom community. Specifically, we found different response patterns for different guilds and size classes to the hydrological and physico-chemical variables, and our results demonstrated that species tolerating high disturbance may be more appropriate as indicators of environmental disturbance than low-tolerant species. We also found dominant effects of short-period hydrological events on biomass and biofilm community functions. Despite an overall negative effect of high flow events and flow variations on biomass and biofilm community functions, positive effects on function-biomass ratios were also observed, indicating that the effects of flow regimes on biofilm are complex. In conclusion, our study highlights the importance of including short-period hydrological conditions in studies on environmental factors shaping benthic algae. Based on our results, we recommend use of short-period hydrological conditions when investigating the effects of flow regime on biofilm community composition and functions.}, } @article {pmid32756660, year = {2020}, author = {Lin, X and Li, Y and Luo, W and Xiao, L and Zhang, Z and Zhao, J and Liu, C and Li, Y}, title = {Leucine-activated nanohybrid biofilm for skin regeneration via improving cell affinity and neovascularization capacity.}, journal = {Journal of materials chemistry. B}, volume = {8}, number = {35}, pages = {7966-7976}, doi = {10.1039/d0tb00958j}, pmid = {32756660}, issn = {2050-7518}, mesh = {Animals ; Biocompatible Materials/*chemistry/*pharmacology ; Cell Line ; Cell Proliferation/drug effects ; Fibroblasts/cytology/drug effects ; Leucine/*chemistry/*pharmacology ; Mice ; Nanostructures/chemistry ; Neovascularization, Physiologic/*drug effects ; Polyesters/chemistry ; Regeneration/*drug effects ; Skin/blood supply/*drug effects ; }, abstract = {The accumulation of skin diseases has increased the need for biomimicking materials with high bioactivity and biosafety for wound healing, where how to improve the cell affinity of the skin regenerative materials as well as their neovascularization capacity is a key factor for rapid regeneration of the injured skin tissue. In the current study, we developed an advanced type of biodegradable nanofibrous biofilm which can attract skin-related cells and accelerate blood vessel formation for skin regeneration. Firstly, bioactive nanohybrids (LEU@LP) were fabricated via in situ doping of the nutrient amino acid leucine (beneficial for fibroblast proliferation and protein synthesis) into LAPONITE® nanodisks (enriched in Mg and Si favorable for vascularization). LEU@LP nanoparticles were then hybridized with a biodegradable polylactide (PLA) nanofibrous mesh via an airbrushing technique, followed by a subsequent ammonia plasma surface treatment to improve PLA's hydrophilicity to increase cell affinity. The resulting hybrid biofilms with skin-biomimicking nanofibrous structural networks can promote cell adhesion, spreading, migration and proliferation of fibroblasts, leading to the ideal skin wound healing (with blood vessel formation and hair follicle regeneration), probably attributed to their better hydrophilicity to promote cell affinity and the capacity of sustainable release of leucine (beneficial for fibroblasts proliferation) and the composition provision (Mg and Si which are beneficial for neovascularization).}, } @article {pmid32756432, year = {2020}, author = {Mangzira Kemung, H and Tan, LT and Chan, KG and Ser, HL and Law, JW and Lee, LH and Goh, BH}, title = {Streptomyces sp. Strain MUSC 125 from Mangrove Soil in Malaysia with Anti-MRSA, Anti-Biofilm and Antioxidant Activities.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {15}, pages = {}, pmid = {32756432}, issn = {1420-3049}, support = {FRGS grant to KGC grant no: FP022-2018A//University of Malaya Research Grant/ ; vote no. GBA-81811A//External Industry Grant from Biotek Abadi Sdn Bhd/ ; GA-HW-19-L01 & GA-HW-19-S02//Monash Global Asia in the 21st Century (GA21) research grants/ ; FRGS/1/2019/WAB09/MUSM/02/1 & FRGS/1/2019/SKK08/MUSM/02/7//Fundamental Research Grant Scheme/ ; }, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Antioxidants/*chemistry ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; DNA, Bacterial/genetics/metabolism ; Gas Chromatography-Mass Spectrometry ; Malaysia ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Microbial Sensitivity Tests ; Multigene Family ; Phenotype ; Phylogeny ; Polyketide Synthases/genetics ; RNA, Ribosomal, 16S/classification/genetics/metabolism ; *Soil Microbiology ; Streptomyces/*chemistry/classification/isolation & purification ; }, abstract = {There is an urgent need to search for new antibiotics to counter the growing number of antibiotic-resistant bacterial strains, one of which is methicillin-resistant Staphylococcus aureus (MRSA). Herein, we report a Streptomyces sp. strain MUSC 125 from mangrove soil in Malaysia which was identified using 16S rRNA phylogenetic and phenotypic analysis. The methanolic extract of strain MUSC 125 showed anti-MRSA, anti-biofilm and antioxidant activities. Strain MUSC 125 was further screened for the presence of secondary metabolite biosynthetic genes. Our results indicated that both polyketide synthase (pks) gene clusters, pksI and pksII, were detected in strain MUSC 125 by PCR amplification. In addition, gas chromatography-mass spectroscopy (GC-MS) detected the presence of different chemicals in the methanolic extract. Based on the GC-MS analysis, eight known compounds were detected suggesting their contribution towards the anti-MRSA and anti-biofilm activities observed. Overall, the study bolsters the potential of strain MUSC 125 as a promising source of anti-MRSA and antibiofilm compounds and warrants further investigation.}, } @article {pmid32756304, year = {2020}, author = {Pradal, I and Esteban, J and Mediero, A and García-Coca, M and Aguilera-Correa, JJ}, title = {Contact Effect of a Methylobacterium sp. Extract on Biofilm of a Mycobacterium chimaera Strain Isolated from a 3T Heater-Cooler System.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32756304}, issn = {2079-6382}, support = {PI18/01068//Instituto de Salud Carlos III/ ; PT17/0019//Instituto de Salud Carlos III/ ; }, abstract = {Mycobacterium chimaera is an opportunistic slowly growing non-tuberculous mycobacteriumof increasing importance due to the outbreak of cases associated with contaminated 3T heater-cooler device (HCD) extracorporeal membrane oxygenator (ECMO). The aim of this study was to evaluate the effect of pre-treating a surface with a Methylobacterium sp. CECT 7180 extract to inhibit the M. chimaera ECMO biofilm as well as of the treatment after different dehydration times. Surface adherence, biofilm formation and treatment effect were evaluated by estimating colony-forming units (CFU) per square centimeter and characterizing the amount of covered surface area, thickness, cell viability, and presence of intrinsic autofluorescence at different times using confocal laser scanning microscopy and image analysis. We found that exposing a surface to the Methylobacterium sp. CECT 7180 extract inhibited M. chimaera ECMO biofilm development. This effect could be result of the effect of Methylobacterium proteins, such as DNaK, trigger factor, and xanthine oxidase. In conclusion, exposing a surface to the Methylobacteriumsp. extract inhibits M. chimaera ECMO biofilm development. Furthermore, this extract could be used as a pre-treatment prior to disinfection protocols for equipment contaminated with mycobacteria after dehydration for at least 96 h.}, } @article {pmid32754136, year = {2020}, author = {Petruzzi, B and Dickerman, A and Lahmers, K and Scarratt, WK and Inzana, TJ}, title = {Polymicrobial Biofilm Interaction Between Histophilus somni and Pasteurella multocida.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1561}, pmid = {32754136}, issn = {1664-302X}, abstract = {Histophilus somni and Pasteurella multocida are two of multiple agents responsible for bovine respiratory disease (BRD) in cattle. Following respiratory infection of calves with H. somni, P. multocida may also be isolated from the lower respiratory tract. Because H. somni may form a biofilm during BRD, we sought to determine if P. multocida can co-exist with H. somni in a polymicrobial biofilm in vitro and in vivo. Interactions between the two species in the biofilm were characterized and quantified by fluorescence in situ hybridization (FISH). The biofilm matrix of each species was examined using fluorescently tagged lectins (FTL) specific for the exopolysaccharide (EPS) using confocal laser scanning microscopy. Bacterial interactions were determined by auto-aggregation and biofilm morphology. Pasteurella multocida and H. somni were evenly distributed in the in vitro biofilm, and both species contributed to the polymicrobial biofilm matrix. The average biomass and biofilm thickness, and the total carbohydrate and protein content of the biofilm, were greatest when both species were present. Polymicrobial bacterial suspensions auto-aggregated faster than single species suspensions, suggesting physical interactions between the two species. Almost 300 P. multocida genes were significantly differentially regulated when the bacteria were in a polymicrobial biofilm compared to a mono-species biofilm, as determined by RNA-sequencing. As expected, host genes associated with inflammation and immune response were significantly upregulated at the infection site following H. somni challenge. Encapsulated P. multocida isolates not capable of forming a substantial biofilm enhanced an in vitro polymicrobial biofilm with H. somni, indicating they contributed to the polymicrobial biofilm matrix. Indirect evidence indicated that encapsulated P. multocida also contributed to a polymicrobial biofilm in vivo. Only the EPS of H. somni could be detected by FTL staining of bovine tissues following challenge with H. somni. However, both species were isolated and an immune response to the biofilm matrix of both species was greater than the response to planktonic cells, suggesting encapsulated P. multocida may take advantage of the H. somni biofilm to persist in the host during chronic BRD. These results may have important implications for the management and prevention of BRD.}, } @article {pmid32754126, year = {2020}, author = {Gonçalves, LNC and Costa-Orlandi, CB and Bila, NM and Vaso, CO and Da Silva, RAM and Mendes-Giannini, MJS and Taylor, ML and Fusco-Almeida, AM}, title = {Biofilm Formation by Histoplasma capsulatum in Different Culture Media and Oxygen Atmospheres.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1455}, pmid = {32754126}, issn = {1664-302X}, abstract = {Histoplasma capsulatum is a dimorphic fungus that causes an important systemic mycosis called histoplasmosis. It is an infectious disease with high prevalence and morbidity that affects the general population. Recently, the ability of these fungi to form biofilms, a phenotype that can induce resistance and enhance virulence, has been described. Despite some efforts, data regarding the impact of nutrients and culture media that affect the H. capsulatum biofilm development in vitro are not yet available. This work aimed to study H. capsulatum biofilms, by checking the influence of different culture media and oxygen atmospheres in the development of these communities. The biofilm formation by two strains (EH-315 and G186A) was characterized under different culture media: [Brain and Heart Infusion (BHI), Roswell Park Memorial Institute (RPMI) with 2% glucose, Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% fetal bovine serum and nutrient medium HAM-F12 (HAM-F12) supplemented with glucose (18.2 g/L), glutamic acid (1 g/L), HEPES (6 g/L) and L-cysteine (8.4 mg/L)] and oxygen atmospheres (aerobiosis and microaerophilia), using the XTT reduction assay to quantify metabolic activities, crystal violet staining for biomass, safranin staining for the quantification of polysaccharide material and scanning electron microscopy (SEM) for the observation of topographies. Results indicated that although all culture mediums have stimulated the maturation of the communities, HAM-F12 provided the best development of biomass and polysaccharide material when compared to others. Regarding the oxygen atmospheres, both stimulated an excellent development of the communities, however in low oxygen conditions an exuberant amount of extracellular matrix was observed when compared to biofilms formed in aerobiosis, mainly in the HAM-F12 media. SEM images showed yeasts embedded by an extracellular matrix in several points, corroborating the colorimetric assays. However, biofilms formed in BHI, RPMI, and DMEM significantly induced yeast to hyphae reversal, requiring further investigation. The results obtained so far contribute to in vitro study of biofilms formed by these fungi and show that nutrition promoted by different media modifies the development of these communities. These data represent advances in the field of biofilms and contribute to future studies that can prove the role of these communities in the fungi-host interaction.}, } @article {pmid32753866, year = {2020}, author = {Fulaz, S and Devlin, H and Vitale, S and Quinn, L and O'Gara, JP and Casey, E}, title = {Tailoring Nanoparticle-Biofilm Interactions to Increase the Efficacy of Antimicrobial Agents Against Staphylococcus aureus.}, journal = {International journal of nanomedicine}, volume = {15}, number = {}, pages = {4779-4791}, pmid = {32753866}, issn = {1178-2013}, mesh = {Anti-Infective Agents/*pharmacology ; *Biofilms/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects/*physiology/ultrastructure ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry/ultrastructure ; Proton Magnetic Resonance Spectroscopy ; Silicon Dioxide/chemistry ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing old drugs and improving antimicrobial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are common causes of biofilm-associated infections but produce different biofilm matrices. MSSA biofilm cells are typically embedded in an extracellular polysaccharide matrix, whereas MRSA biofilms comprise predominantly of surface proteins and extracellular DNA (eDNA). Nanoparticles (NPs) have the potential to enhance the delivery of antimicrobial agents into biofilms. However, the mechanisms which influence the interactions between NPs and the biofilm matrix are not yet fully understood.

METHODS: To investigate the influence of NPs surface chemistry on vancomycin (VAN) encapsulation and NP entrapment in MRSA and MSSA biofilms, mesoporous silica nanoparticles (MSNs) with different surface functionalization (bare-B, amine-D, carboxyl-C, aromatic-A) were synthesised using an adapted Stöber method. The antibacterial efficacy of VAN-loaded MSNs was assessed against MRSA and MSSA biofilms.

RESULTS: The two negatively charged MSNs (MSN-B and MSN-C) showed a higher VAN loading in comparison to the positively charged MSNs (MSN-D and MSN-A). Cellular binding with MSN suspensions (0.25 mg mL[-1]) correlated with the reduced viability of both MSSA and MRSA biofilm cells. This allowed the administration of low MSNs concentrations while maintaining a high local concentration of the antibiotic surrounding the bacterial cells.

CONCLUSION: Our data suggest that by tailoring the surface functionalization of MSNs, enhanced bacterial cell targeting can be achieved, leading to a novel treatment strategy for biofilm infections.}, } @article {pmid32753507, year = {2020}, author = {Otto, SB and Martin, M and Schäfer, D and Hartmann, R and Drescher, K and Brix, S and Dragoš, A and Kovács, ÁT}, title = {Privatization of Biofilm Matrix in Structurally Heterogeneous Biofilms.}, journal = {mSystems}, volume = {5}, number = {4}, pages = {}, pmid = {32753507}, issn = {2379-5077}, abstract = {The self-produced biofilm provides beneficial protection for the enclosed cells, but the costly production of matrix components makes producer cells susceptible to cheating by nonproducing individuals. Despite detrimental effects of nonproducers, biofilms can be heterogeneous, with isogenic nonproducers being a natural consequence of phenotypic differentiation processes. For instance, in Bacillus subtilis biofilm cells differ in production of the two major matrix components, the amyloid fiber protein TasA and exopolysaccharides (EPS), demonstrating different expression levels of corresponding matrix genes. This raises questions regarding matrix gene expression dynamics during biofilm development and the impact of phenotypic nonproducers on biofilm robustness. Here, we show that biofilms are structurally heterogeneous and can be separated into strongly and weakly associated clusters. We reveal that spatiotemporal changes in structural heterogeneity correlate with matrix gene expression, with TasA playing a key role in biofilm integrity and timing of development. We show that the matrix remains partially privatized by the producer subpopulation, where cells tightly stick together even when exposed to shear stress. Our results support previous findings on the existence of "weak points" in seemingly robust biofilms as well as on the key role of linkage proteins in biofilm formation. Furthermore, we provide a starting point for investigating the privatization of common goods within isogenic populations.IMPORTANCE Biofilms are communities of bacteria protected by a self-produced extracellular matrix. The detrimental effects of nonproducing individuals on biofilm development raise questions about the dynamics between community members, especially when isogenic nonproducers exist within wild-type populations. We asked ourselves whether phenotypic nonproducers impact biofilm robustness, and where and when this heterogeneity of matrix gene expression occurs. Based on our results, we propose that the matrix remains partly privatized by the producing subpopulation, since producing cells stick together when exposed to shear stress. The important role of linkage proteins in robustness and development of the structurally heterogeneous biofilm provides an entry into studying the privatization of common goods within isogenic populations.}, } @article {pmid32753311, year = {2020}, author = {Alam, K and Farraj, DAA and Mah-E-Fatima, S and Yameen, MA and Elshikh, MS and Alkufeidy, RM and Mustafa, AEMA and Bhasme, P and Alshammari, MK and Alkubaisi, NA and Abbasi, AM and Naqvi, TA}, title = {Anti-biofilm activity of plant derived extracts against infectious pathogen-Pseudomonas aeruginosa PAO1.}, journal = {Journal of infection and public health}, volume = {13}, number = {11}, pages = {1734-1741}, doi = {10.1016/j.jiph.2020.07.007}, pmid = {32753311}, issn = {1876-035X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Humans ; Pakistan ; *Plant Extracts/pharmacology ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing ; Virulence Factors ; }, abstract = {BACKGROUND: Biofilm forming ability of Pseudomonas aeruginosa make them vulnerable, because it makes them recalcitrant against various antibiotics. Quorum sensing (QS) is cell density based signaling that helps in bacterial cell-cell communication, which regulated various virulence factors such as pigment and biofilm formation that contribute in the establishment of chronic infections. The interruption of QS is one of the effective approach to control various virulence factors. Present study was intended with the aim to authenticate antibiofilm potential in different solvents based extracts of selected medicinal plant species viz. Berginia ciliata, Clematis grata and Clematis viticella traditionally used by the inhabitants of Himalayan region of Pakistan to treat various pathogenic diseases. P. aeruginosa PAO1, an opportunistic pathogen and involves in various life-threatening infections specifically in immune deficient patients was used as a model pathogen.

METHODS: Plants were extracted in various organic (ethanol, methanol, acetone, ethyl acetate, hexane, chloroform) as well as in aqueous solvents and their ability to inhibit biofilm was measured. Biofilm of PAO1 was grown in Jensen's medium while growing at 30°C and crystal violet assay was performed to assess the biofilm inhibiting activity of plant extracts.

RESULTS: Solvents play a vital role in extraction of plant components and it was found that the plants in various solvents exhibit different activity against the PAO1 biofilm. Comparatively, 1% methanolic extract of B. ciliata (rhizome with skin), showed more than 80% inhibition of biofilm formation without effecting on the growth of the bacterium. Significant correlation between flavonoids content and antibiofilm activity in methanolic extract revealed the contribution of secondary metabolites in P. aeruginosa (PAO1) biofilm inhibition.

CONCLUSION: Our study revealed that plants under investigation more specifically B. ciliata could be a potential candidate for drug discovery to treat P. aeruginosa PAO1, induced infectious diseases especially for its biofilm treatment.}, } @article {pmid32752248, year = {2020}, author = {Mitwalli, H and Balhaddad, AA and AlSahafi, R and Oates, TW and Melo, MAS and Xu, HHK and Weir, MD}, title = {Novel CaF2 Nanocomposites with Antibacterial Function and Fluoride and Calcium Ion Release to Inhibit Oral Biofilm and Protect Teeth.}, journal = {Journal of functional biomaterials}, volume = {11}, number = {3}, pages = {}, pmid = {32752248}, issn = {2079-4983}, abstract = {(1) Background: The objective of this study was to develop a novel dental nanocomposite containing dimethylaminohexadecyl methacrylate (DMAHDM), 2-methacryloyloxyethyl phosphorylcholine (MPC), and nanoparticles of calcium fluoride (nCaF2) for preventing recurrent caries via antibacterial, protein repellent and fluoride releasing capabilities. (2) Methods: Composites were made by adding 3% MPC, 3% DMAHDM and 15% nCaF2 into bisphenol A glycidyl dimethacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (denoted BT). Calcium and fluoride ion releases were evaluated. Biofilms of human saliva were assessed. (3) Results: nCaF2+DMAHDM+MPC composite had the lowest biofilm colony forming units (CFU) and the greatest ion release; however, its mechanical properties were lower than commercial control composite (p < 0.05). nCaF2+DMAHDM composite had similarly potent biofilm reduction, with mechanical properties matching commercial control composite (p > 0.05). Fluoride and calcium ion releases from nCaF2+DMAHDM were much more than commercial composite. Biofilm CFU on composite was reduced by 4 logs (n = 9, p < 0.05). Biofilm metabolic activity and lactic acid were also substantially reduced by nCaF2+DMAHDM, compared to commercial control composite (p < 0.05). (4) Conclusions: The novel nanocomposite nCaF2+DMAHDM achieved strong antibacterial and ion release capabilities, without compromising the mechanical properties. This bioactive nanocomposite is promising to reduce biofilm acid production, inhibit recurrent caries, and increase restoration longevity.}, } @article {pmid32751780, year = {2020}, author = {Hasan, M and Zafar, A and Shahzadi, I and Luo, F and Hassan, SG and Tariq, T and Zehra, S and Munawar, T and Iqbal, F and Shu, X}, title = {Fractionation of Biomolecules in Withania coagulans Extract for Bioreductive Nanoparticle Synthesis, Antifungal and Biofilm Activity.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {15}, pages = {}, pmid = {32751780}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antifungal Agents/*pharmacology ; Aspergillus niger/drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects ; Chemical Fractionation/methods ; Cobalt/*chemistry ; Hexanes/chemistry ; Metal Nanoparticles/*chemistry ; Methanol/chemistry ; Microbial Sensitivity Tests ; Oxides/*chemistry ; Phytochemicals/*pharmacology ; Plant Extracts/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Solvents/chemistry ; Staphylococcus aureus/drug effects ; Withania/*chemistry ; }, abstract = {Withania coagulans contains a complex mixture of various bioactive compounds. In order to reduce the complexity of the plant extract to purify its phytochemical biomolecules, a novel fractionation strategy using different solvent combination ratios was applied to isolate twelve bioactive fractions. These fractions were tested for activity in the biogenic synthesis of cobalt oxide nanoparticles, biofilm and antifungal activities. The results revealed that plant extract with bioactive fractions in 30% ratio for all solvent combinations showed more potent bioreducing power, according to the observed color changes and the appearance of representative absorption peaks at 500-510 nm in the UV-visible spectra which confirm the synthesis of cobalt oxide nanoparticles (Co3O4 NPs). XRD diffraction was used to define the crystal structure, size and phase composition of the products. The fractions obtained using 90% methanol/hexane and 30% methanol/hexane showed more effectiveness against biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus so these fractions could potentially be used to treat bacterial infections. The 90% hexane/H2O fraction showed excellent antifungal activity against Aspergillus niger and Candida albicans, while the 70% methanol/hexane fraction showed good antifungal activity for C. albicans, so these fractions are potentially useful for the treatment of various fungal infections. On the whole it was concluded that fractionation based on effective combinations of methanol/hexane was useful to investigate and study bioactive compounds, and the active compounds from these fractions may be further purified and tested in various clinical trials.}, } @article {pmid32751652, year = {2020}, author = {Mitwalli, H and Alsahafi, R and Balhaddad, AA and Weir, MD and Xu, HHK and Melo, MAS}, title = {Emerging Contact-Killing Antibacterial Strategies for Developing Anti-Biofilm Dental Polymeric Restorative Materials.}, journal = {Bioengineering (Basel, Switzerland)}, volume = {7}, number = {3}, pages = {}, pmid = {32751652}, issn = {2306-5354}, support = {n/a//University of Maryland School of Dentistry departmental fund/ ; }, abstract = {Polymeric materials are the first choice for restoring tooth cavities, bonding tooth-colored fillings, sealing root canal systems, and many other dental restorative applications. However, polymeric materials are highly susceptible to bacterial attachment and colonization, leading to dental diseases. Many approaches have been investigated to minimize the formation of biofilms over polymeric restorative materials and at the tooth/material interfaces. Among them, contact-killing compounds have shown promising results to inhibit dental biofilms. Contact-killing compounds can be immobilized within the polymer structure, delivering a long-lasting effect with no leaching or release, thus providing advantages compared to release-based materials. This review discusses cutting-edge research on the development of contact-killing compounds in dental restorative materials to target oral pathogens. Contact-killing compounds in resin composite restorations, dental adhesives, root canal sealers, denture-based materials, and crown cements have all demonstrated promising antibacterial properties. Contact-killing restorative materials have been found to effectively inhibit the growth and activities of several oral pathogens related to dental caries, periodontal diseases, endodontic, and fungal infections. Further laboratory optimization and clinical trials using translational models are needed to confirm the clinical applicability of this new generation of contact-killing dental restorative materials.}, } @article {pmid32751577, year = {2020}, author = {Verran, J and Jackson, S and Scimone, A and Kelly, P and Redfern, J}, title = {Biofilm Control Strategies: Engaging with the Public.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32751577}, issn = {2079-6382}, abstract = {There are few peer-reviewed publications about public engagement with science that are written by microbiologists; those that exist tend to be a narrative of an event rather than a hypothesis-driven investigation. However, it is relatively easy for experienced scientists to use a scientific method in their approach to public engagement. This short communication describes three public engagement activities hosted by the authors, focused on biofilm control: hand hygiene, plaque control and an externally applied antimicrobial coating. In each case, audience engagement was assessed using quantitative and/or qualitative methods. A critical evaluation of the findings enabled the construction of a public engagement 'tick list' for future events that would enable a hypothesis-driven approach with more effective communication activities and more robust evaluation.}, } @article {pmid32751457, year = {2020}, author = {Al Azzaz, J and Al Tarraf, A and Heumann, A and Da Silva Barreira, D and Laurent, J and Assifaoui, A and Rieu, A and Guzzo, J and Lapaquette, P}, title = {Resveratrol Favors Adhesion and Biofilm Formation of Lacticaseibacillus paracasei subsp. paracasei Strain ATCC334.}, journal = {International journal of molecular sciences}, volume = {21}, number = {15}, pages = {}, pmid = {32751457}, issn = {1422-0067}, support = {2014FR16M0OP014//European Regional Development Fund/ ; Inprobiaus//Institut Carnot Qualiment/ ; }, mesh = {Bacterial Adhesion/*drug effects ; HCT116 Cells ; HT29 Cells ; Humans ; *Lacticaseibacillus paracasei/drug effects/growth & development ; Probiotics/*metabolism ; Resveratrol/*pharmacology ; }, abstract = {Bacterial strains of the Lactobacillaceae family are widely used as probiotics for their multifaceted potential beneficial properties. However, no official recommendations for their clinical use exist since, in many cases, oral administrations of these bacteria displayed limited beneficial effects in human. Additional research is thus needed to improve the efficiency of existing strains with strong potential. In this context, we assess in vitro the effects of nine polyphenols to stimulate biofilm formation by lactobacilli, a feature enhancing their functionalities. Among these polyphenols, we identify trans-Resveratrol (referred to hereafter as Resveratrol) as a potent inducer of biofilm formation by Lacticaseibacillus paracasei (formerly designated as Lactobacillus paracasei) ATCC334 strain. This effect is strain-dependent and relies on the enhancement of L. paracasei adhesion to abiotic and biotic surfaces, including intestinal epithelial cells. Mechanistically, Resveratrol modify physico-chemical properties of the bacterial surface and thereby enhances L. paracasei aggregation, subsequently facilitating adhesion and biofilm development. Together, our in vitro data demonstrate that Resveratrol might be used to modulate the behavior of Lactobacilli with probiotic properties. Combination of probiotics and polyphenols could be considered to enhance the probiotic functionalities in further in vivo studies.}, } @article {pmid32751405, year = {2020}, author = {Vazquez-Munoz, R and Lopez, FD and Lopez-Ribot, JL}, title = {Bismuth Nanoantibiotics Display Anticandidal Activity and Disrupt the Biofilm and Cell Morphology of the Emergent Pathogenic Yeast Candida auris.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32751405}, issn = {2079-6382}, abstract = {Candida auris is an emergent multidrug-resistant pathogenic yeast, which forms biofilms resistant to antifungals, sanitizing procedures, and harsh environmental conditions. Antimicrobial nanomaterials represent an alternative to reduce the spread of pathogens-including yeasts-regardless of their drug-resistant profile. Here we have assessed the antimicrobial activity of easy-to-synthesize bismuth nanoparticles (BiNPs) against the emergent multidrug-resistant yeast Candida auris, under both planktonic and biofilm growing conditions. Additionally, we have examined the effect of these BiNPs on cell morphology and biofilm structure. Under planktonic conditions, BiNPs MIC values ranged from 1 to 4 µg mL[-1] against multiple C. auris strains tested, including representatives of all different clades. Regarding the inhibition of biofilm formation, the calculated BiNPs IC50 values ranged from 5.1 to 113.1 µg mL[-1]. Scanning electron microscopy (SEM) observations indicated that BiNPs disrupted the C. auris cell morphology and the structure of the biofilms. In conclusion, BiNPs displayed strong antifungal activity against all strains of C. auris under planktonic conditions, but moderate activity against biofilm growth. BiNPs may potentially contribute to reducing the spread of C. auris strains at healthcare facilities, as sanitizers and future potential treatments. More research on the antimicrobial activity of BiNPs is warranted.}, } @article {pmid32750675, year = {2020}, author = {Mukherjee, M and Zaiden, N and Teng, A and Hu, Y and Cao, B}, title = {Shewanella biofilm development and engineering for environmental and bioenergy applications.}, journal = {Current opinion in chemical biology}, volume = {59}, number = {}, pages = {84-92}, doi = {10.1016/j.cbpa.2020.05.004}, pmid = {32750675}, issn = {1879-0402}, mesh = {Bacterial Proteins/genetics/metabolism ; Biodegradation, Environmental ; Bioelectric Energy Sources/microbiology ; Biofilms/*growth & development ; Genetic Engineering ; Quorum Sensing ; Shewanella/genetics/*physiology ; }, abstract = {The genus Shewanella comprises about 70 species of Gram-negative, facultative anaerobic bacteria inhabiting various environments, which have shown great potential in various biotechnological applications ranging from environmental bioremediation, metal(loid) recovery and material synthesis to bioenergy generation. Most environmental and energy applications of Shewanella involve the biofilm mode of growth on surfaces of solid minerals or electrodes. In this article, we first provide an overview of Shewanella biofilm biology with the focus on biofilm dynamics, biofilm matrix, and key signalling systems involved in Shewanella biofilm development. Then we review strategies recently exploited to engineer Shewanella biofilms to improve biofilm-mediated bioprocesses.}, } @article {pmid32750589, year = {2021}, author = {Liu, L and Ji, M and Wang, F and Tian, Z and Yan, Z and Wang, S}, title = {N-acyl-l-homoserine lactones release and microbial community changes in response to operation temperature in an anammox biofilm reactor.}, journal = {Chemosphere}, volume = {262}, number = {}, pages = {127602}, doi = {10.1016/j.chemosphere.2020.127602}, pmid = {32750589}, issn = {1879-1298}, mesh = {Bacteria/classification ; Biofilms ; Biomass ; Bioreactors/*microbiology ; Homoserine/*metabolism ; Lactones/*metabolism ; *Microbiota ; Nitrogen ; Oxidation-Reduction ; Quorum Sensing ; Temperature ; }, abstract = {A 1 L lab-scale anaerobic ammonium oxidation (anammox) biofilm reactor with nitrogen loading rate of 0.11 g/L d was run for 110 days with the operation temperature declining from 36 °C to 15 °C. The total inorganic nitrogen removal efficiency showed a reduction from 80% to 66%, when the temperature declined from 36 °C to 15 °C. N-acyl-l-homoserine lactones (AHLs) concentrations, especially C8-HSL and C6-HSL, declined in both water and biomass phases, and this decline indicated that the quorum sensing weakened. Microbial community analysis revealed that Candidatus Kuenenia was the predominant anammox bacteria during the entire operating period. The abundance of Candidatus Kuenenia increased from 1.43% to 22.89% when the temperature decreasing from 36 °C to 15 °C. The correlation between microbial genus and AHLs was complicated. Overall, the temperature decrease weakened the quorum sensing so that the nitrogen removal performance deteriorated, and increasing the anammox activity might be an efficient way to improve performance.}, } @article {pmid32749905, year = {2020}, author = {Sikdar, R and Elias, M}, title = {Quorum quenching enzymes and their effects on virulence, biofilm, and microbiomes: a review of recent advances.}, journal = {Expert review of anti-infective therapy}, volume = {18}, number = {12}, pages = {1221-1233}, pmid = {32749905}, issn = {1744-8336}, support = {R35 GM133487/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacteria/*pathogenicity ; *Biofilms ; Humans ; Microbiota/physiology ; Quorum Sensing/*physiology ; Virulence/physiology ; }, abstract = {INTRODUCTION: Numerous bacterial behaviors are regulated by a cell-density dependent mechanism known as Quorum Sensing (QS). QS relies on communication between bacterial cells using diffusible signaling molecules known as autoinducers. QS regulates physiological processes such as metabolism, virulence, and biofilm formation. Quorum Quenching (QQ) is the inhibition of QS using chemical or enzymatic means to counteract behaviors regulated by QS.

AREAS COVERED: We examine the main, diverse QS mechanisms present in bacterial species, with a special emphasis on AHL-mediated QS. We also discuss key in vitro and in vivo systems in which interference in QS was investigated. Additionally, we highlight promising developments, such as the substrate preference of the used enzymatic quencher, in the application of interference in QS to counter bacterial virulence.

EXPERT OPINION: Enabled via the recent isolation of highly stable quorum quenching enzymes and/or molecular engineering efforts, the effects of the interference in QS were recently evaluated outside of the traditional model of single species culture. Signal disruption in complex microbial communities was shown to result in the disruption of complex microbial behaviors, and changes in population structures. These new findings, and future studies, may result in significant changes in the traditional views about QS.}, } @article {pmid32749521, year = {2020}, author = {Sowndarya, J and Rubini, D and Sinsinwar, S and Senthilkumar, M and Nithyanand, P and Vadivel, V}, title = {Gallic Acid an Agricultural Byproduct Modulates the Biofilm Matrix Exopolysaccharides of the Phytopathogen Ralstonia solanacearum.}, journal = {Current microbiology}, volume = {77}, number = {11}, pages = {3339-3354}, pmid = {32749521}, issn = {1432-0991}, mesh = {Extracellular Polymeric Substance Matrix ; Gallic Acid/pharmacology ; *Solanum lycopersicum ; Plant Diseases ; *Ralstonia solanacearum ; Virulence ; }, abstract = {Ralstonia solanacearum is a soil-borne plant pathogen which causes wilt disease in economically important crops of the Solanaceae family in tropical and temperate regions. As biofilm formation is the major virulence factor in R. solanacearum, research inputs are necessary to identify natural biofilm inhibitors to mitigate virulence of this bacterium. Hence in the present work, the anti-biofilm potential of phytochemical compound gallic acid (GA) isolated from an agricultural byproduct (cashewnut shell) was investigated. Initially the Minimum inhibitory concentration (MIC) of crude extracts of cashewnut shell and coconut shell against R. solanacearum were investigated. The MIC of both the extracts were 400 µg/ml and their sub-MIC (200 µg/ml) inhibited biofilms in the range of 62-70% and 49-57%, respectively. As the cashewnut shell extract have higher biofilm inhibitory effect compared to coconut shell extract, we proceeded our further study by isolating the major compound GA from cashewnut shell by acid hydrolysate method. The sub-MIC of crude cashewnut shell extract inhibited 85% of young biofilms. The MIC of GA were observed at 3 mg/ml and sub-MIC (1.5 mg/ml) was found to eradicate 85% of mature biofilms which was confirmed by standard crystal violet assay and the biofilm reduction was further visualized under light microscopy and scanning electron microscopic images. Toxicity of GA was evaluated against R. solanacearum through XTT cell viability assay and found no antibacterial effect at sub-MIC. Additionally, it is confirmed with growth curve and time kill assays. Swimming and twitching motility were considered as an important virulence factors to invade plants and to block the xylem vessels. Therefore, sub-MIC of GA was found to inhibit both swimming and twitching motility of about 93% and 63% respectively. Anti-biofilm efficacy of GA was also worked well with tomato plant model where remarkable biofilm inhibition was found on treatment with GA before and after 24 h of infection with R. solanacearum. Hence GA will be an alternative, cheap source which is eco-friendly as well as novel source for the treatment of R. solanacearum biofilms and to prevent wilt disease in important crops.}, } @article {pmid32749122, year = {2020}, author = {Kou, J and Xin, TY and McCarron, P and Gupta, G and Dureja, H and Satija, S and Mehta, M and Bakshi, HA and Tambuwala, MM and Collet, T and Dua, K and Chellappan, DK}, title = {Going Beyond Antibiotics: Natural Plant Extracts as an Emergent Strategy to Combat Biofilm-Associated Infections.}, journal = {Journal of environmental pathology, toxicology and oncology : official organ of the International Society for Environmental Toxicology and Cancer}, volume = {39}, number = {2}, pages = {125-136}, doi = {10.1615/JEnvironPatholToxicolOncol.2020032665}, pmid = {32749122}, issn = {2162-6537}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/*drug effects ; Host-Pathogen Interactions ; Humans ; Infections/*drug therapy/microbiology ; Plant Extracts/*pharmacology/therapeutic use ; Quorum Sensing/drug effects ; }, abstract = {Biofilms are a collective of multiple types of bacteria that develop on a variety of surfaces. Biofilm development results in heightened resistance to antibiotics. Quorum sensing plays an important role in biofilm development as it is one of the common communication mechanisms within cells, which balances and stabilizes the environment, when the amount of bacteria increases. Because of the important implications of the roles biofilms play in infectious diseases, it is crucial to investigate natural antibacterial agents that are able to regulate biofilm formation and development. Various studies have suggested that natural plant products have the potential to suppress bacterial growth and exhibit chemopreventive traits in the modulation of biofilm development. In this review, we discuss and collate potential antibiofilm drugs and biological molecules from natural sources, along with their underlying mechanisms of action. In addition, we also discuss the antibiofilm drugs that are currently under clinical trials and highlight their potential future uses.}, } @article {pmid32748817, year = {2020}, author = {Alamri, AM and Alsultan, AA and Ansari, MA and Alnimr, AM}, title = {Biofilm-Formation in Clonally Unrelated Multidrug-Resistant Acinetobacter baumannii Isolates.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32748817}, issn = {2076-0817}, abstract = {This study analyzed the genotype, antibiotic resistance, and biofilm formation of Acinetobacter baumannii strains and assessed the correlation between biofilm formation, antibiotic resistance, and biofilm-related risk factors. A total of 207 non-replicate multi-drug-resistant A. baumannii strains were prospectively isolated. Phenotypic identification and antimicrobial susceptibility testing were carried out. Isolate biofilm formation ability was evaluated using the tissue culture plate (TCP), Congo red agar, and tube methods. Clonal relatedness between the strains was assessed by enterobacterial repetitive intergenic consensus-PCR genotyping. Of the 207 isolates, 52.5% originated from an intensive care unit setting, and pan resistance was observed against ceftazidime and cefepime, with elevated resistance (99-94%) to piperacillin/tazobactam, imipenem, levofloxacin, and ciprofloxacin. alongside high susceptibility to tigecycline (97.8%). The Tissue culture plate, Tube method, and Congo red agar methods revealed that 53.6%, 20.8%, and 2.7% of the strains were strong biofilm producers, respectively, while a significant correlation was observed between biofilm formation and device-originating respiratory isolates (p = 0.0009) and between biofilm formation in colonized vs. true infection isolates (p = 0.0001). No correlation was detected between antibiotic resistance and biofilm formation capacity, and the majority of isolates were clonally unrelated. These findings highlight the urgent need for implementing strict infection control measures in clinical settings.}, } @article {pmid32748136, year = {2020}, author = {Babushkina, IV and Bondarenko, AS and Ulyanov, VY and Mamonova, IA}, title = {Biofilm Formation by Gram-Negative Bacteria during Implant-Associated Infection.}, journal = {Bulletin of experimental biology and medicine}, volume = {169}, number = {3}, pages = {365-368}, doi = {10.1007/s10517-020-04888-5}, pmid = {32748136}, issn = {1573-8221}, mesh = {Biofilms/*growth & development ; Gram-Negative Bacteria/*growth & development/physiology ; Humans ; }, abstract = {Nonfermenting gram-negative bacteria and enterobacteria isolated from various biomaterials of patients of the orthopedic trauma hospital with implant-associated infection demonstrated significantly (p<0.05) higher biofilm formation capacity than the reference strains. The differences in biofilm formation kinetics were revealed: biofilm maturation and the beginning of its dispersion after 48-h incubation in enterobacteria and longer biofilm maturation phase in nonfermenting gram-negative bacteria. It was found that the strains isolated from sonication fluid have reliably (p<0.05) higher propensity to biofilm formation than bacteria isolated from aspirate and wound exudate.}, } @article {pmid32747262, year = {2020}, author = {Szymańska, M and Karakulska, J and Sobolewski, P and Kowalska, U and Grygorcewicz, B and Böttcher, D and Bornscheuer, UT and Drozd, R}, title = {Glycoside hydrolase (PelAh) immobilization prevents Pseudomonas aeruginosa biofilm formation on cellulose-based wound dressing.}, journal = {Carbohydrate polymers}, volume = {246}, number = {}, pages = {116625}, doi = {10.1016/j.carbpol.2020.116625}, pmid = {32747262}, issn = {1879-1344}, mesh = {Acetobacteraceae/*chemistry/physiology ; Animals ; Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Proteins/biosynthesis/genetics/pharmacology ; *Bandages ; Biofilms/*drug effects/growth & development ; Cell Line ; Cellulose/biosynthesis/*chemistry/isolation & purification ; Cloning, Molecular ; Enzymes, Immobilized/biosynthesis/genetics/pharmacology ; Escherichia coli/genetics/metabolism ; Fibroblasts/cytology/drug effects ; Gene Expression ; Genetic Vectors/chemistry/metabolism ; Glycoside Hydrolases/biosynthesis/genetics/*pharmacology ; Mice ; Protein Domains ; Pseudomonas aeruginosa/*drug effects/growth & development/pathogenicity ; Recombinant Proteins/biosynthesis/genetics/pharmacology ; }, abstract = {Bacterial cellulose (BC) is recognized as a wound dressing material well-suited for chronic wounds; however, it has no intrinsic antimicrobial activity. Further, the formation of biofilms can limit the effectiveness of the pre-saturation of BC with antimicrobial agents. Here, to hinder biofilm formation by P. aeruginosa, we immobilized the hydrolytic domain of PelA (a glycohydrolase involved in the synthesis of biofilm polysaccharide Pel) on the surface of BC. The immobilization of 32.35 ± 1.05 mg PelAh per g BC membrane resulted in an eight-fold higher P. aeruginosa cell detachment from BC membrane, indicating reduced biofilm matrix stability. Further, 1D and 2D infrared spectroscopy analysis indicated systematic reduction of polysaccharide biofilm elements, confirming the specificity of immobilized PelAh. Importantly, BC-PelAh was not cytotoxic towards L929 fibroblast cells. Thus, we conclude that PelAh can be used in BC wound dressings for safe and specific protection against biofilm formation by P. aeruginosa.}, } @article {pmid32746783, year = {2020}, author = {Schneider, R and Primon-Barros, M and Von Borowski, RG and Chat, S and Nonin-Lecomte, S and Gillet, R and Macedo, AJ}, title = {Pseudonajide peptide derived from snake venom alters cell envelope integrity interfering on biofilm formation in Staphylococcus epidermidis.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {237}, pmid = {32746783}, issn = {1471-2180}, mesh = {Amino Acid Motifs ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Line ; Cell Membrane/*drug effects/metabolism ; Cell Survival/drug effects ; Cell Wall/*drug effects/metabolism ; Gene Expression/drug effects ; Humans ; Permeability/drug effects ; Snake Venoms/*chemistry ; Staphylococcus epidermidis/*drug effects ; Teichoic Acids/genetics/metabolism ; }, abstract = {BACKGROUND: The increase in bacterial resistance phenotype cases is a global health problem. New strategies must be explored by the scientific community in order to create new treatment alternatives. Animal venoms are a good source for antimicrobial peptides (AMPs), which are excellent candidates for new antimicrobial drug development. Cathelicidin-related antimicrobial peptides (CRAMPs) from snake venoms have been studied as a model for the design of new antimicrobial pharmaceuticals against bacterial infections.

RESULTS: In this study we present an 11 amino acid-long peptide, named pseudonajide, which is derived from a Pseudonaja textilis venom peptide and has antimicrobial and antibiofilm activity against Staphylococcus epidermidis. Pseudonajide was selected based on the sequence alignments of various snake venom peptides that displayed activity against bacteria. Antibiofilm activity assays with pseudonajide concentrations ranging from 3.12 to 100 μM showed that the lowest concentration to inhibit biofilm formation was 25 μM. Microscopy analysis demonstrated that pseudonajide interacts with the bacterial cell envelope, disrupting the cell walls and membranes, leading to morphological defects in prokaryotes.

CONCLUSIONS: Our results suggest that pseudonajide's positives charges interact with negatively charged cell wall components of S. epidermidis, leading to cell damage and inhibiting biofilm formation.}, } @article {pmid32745913, year = {2020}, author = {Liu, Y and Ren, H and Wang, D and Zhang, M and Sun, S and Zhao, Y}, title = {The synergistic antifungal effects of gypenosides combined with fluconazole against resistant Candida albicans via inhibiting the drug efflux and biofilm formation.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {130}, number = {}, pages = {110580}, doi = {10.1016/j.biopha.2020.110580}, pmid = {32745913}, issn = {1950-6007}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/physiology ; Candidiasis/drug therapy ; Drug Resistance, Fungal/*drug effects ; Drug Synergism ; Fluconazole/*pharmacology ; Gynostemma ; Larva/microbiology ; Lepidoptera/microbiology ; Plant Extracts/pharmacology ; }, abstract = {The increased resistance of Candida to conventional antifungals brings great challenges for the clinical treatment of Candida infections. Recently, more attention has been paid to the research on combination therapy, which is a potential therapeutic approach for overcoming Candida resistance. In the present study, we first investigated the interaction between gypenosides (Gyp) and fluconazole (FLC) against Candida albicans (C. albicans) in vitro and in vivo. The in vitro test revealed a synergistic antifungal activity between Gyp and FLC against FLC-resistant (FLC[R]) C. albicans and indifferent effects for FLC-susceptible (FLC[S]) C. albicans, with the fractional inhibitory concentration index of 0.2539-0.2578 and 1-1.5, respectively. Besides, Gyp displayed synergistic interaction with FLC against FLC[R]C. albicans performed biofilm over 4 h, with the fractional inhibitory concentration index <0.5. In vivo, the combined antifungal efficacy of Gyp with FLC was evaluated by Galleria mellonella (G. mellonella) larvae. Gyp plus FLC prolonged the survival rate and reduced tissue invasion of larvae infected with FLC[R]C. albicans. Further experiments to get a first hint at what antifungal mechanisms might be inhibition of early biofilm formation, suppression of drug efflux, and inhibition of yeast-hyphal conversion. These findings will provide a new approach for the treatment of C. albicans infection.}, } @article {pmid32745664, year = {2020}, author = {Liu, T and Luo, J and Bi, G and Du, Z and Kong, J and Chen, Y}, title = {Antibacterial synergy between linezolid and baicalein against methicillin-resistant Staphylococcus aureus biofilm in vivo.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104411}, doi = {10.1016/j.micpath.2020.104411}, pmid = {32745664}, issn = {1096-1208}, mesh = {Animals ; *Anti-Bacterial Agents/pharmacology ; Biofilms ; *Flavanones/pharmacology ; Humans ; *Linezolid/pharmacology ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Rats ; *Staphylococcal Infections/drug therapy ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) can form biofilms, which prevents the penetration of antibiotics, decreasing their efficacy. This study investigated whether baicalein has synergistic antibacterial effects with linezolid in vivo. We cultivated MRSA 17546 biofilms on silicone implants and inserted them into the air pouches of rat models. The rats were treated with linezolid, baicalein, or a combination therapy for three consecutive days. All treatments reduced the number of colony-forming units (CFU) in the biofilms compared to the control (p < 0.05). However, by day two, the CFU counts were significantly lower in the combination group than in the individual treatment groups (p < 0.05). Histological analysis of the air pouches showed that the severity of the inflammatory cell infiltration was severe in the combination therapy group. In the combination group, the biofilm structure on the implant's surface was sparse and more free colonies could be seen by scanning electron microscopy (SEM); by day three, no obvious biofilm was observed. The serum levels of Staphylococcus enterotoxin A (SEA), C-reactive protein (CRP), and procalcitonin (PCT) were the lowest in the group where rats were treated with the combination of baicalein and linezolid (p < 0.05) compared to other groups. The results suggest that baicalein may inhibit the accessory gene regulator system, reducing the expression of SEA, thus lowering CRP and PCT levels. Furthermore, the inhibitory effect was more pronounced when baicalein was combined with linezolid. These results provide an important basis for the development of a new combination regimen to treat patients with biofilm-associated MRSA infections.}, } @article {pmid32744537, year = {2020}, author = {Manfiolli, AO and Dos Reis, TF and de Assis, LJ and de Castro, PA and Silva, LP and Hori, JI and Walker, LA and Munro, CA and Rajendran, R and Ramage, G and Goldman, GH}, title = {Erratum to "Mitogen activated protein kinases (MAPK) and protein phosphatases are involved in Aspergillus fumigatus adhesion and biofilm formation" [Cell Surf. 1 (2018) 43-56].}, journal = {Cell surface (Amsterdam, Netherlands)}, volume = {6}, number = {}, pages = {100035}, doi = {10.1016/j.tcsw.2020.100035}, pmid = {32744537}, issn = {2468-2330}, abstract = {[This corrects the article DOI: 10.1016/j.tcsw.2018.03.002.].}, } @article {pmid32743877, year = {2020}, author = {Chen, G and Gan, J and Yang, C and Zuo, Y and Peng, J and Li, M and Huo, W and Xie, Y and Zhang, Y and Wang, T and Deng, X and Liang, H}, title = {The SiaA/B/C/D signaling network regulates biofilm formation in Pseudomonas aeruginosa.}, journal = {The EMBO journal}, volume = {39}, number = {15}, pages = {e105997}, pmid = {32743877}, issn = {1460-2075}, } @article {pmid32742809, year = {2020}, author = {Gaio, V and Cerca, N}, title = {Biofilm released cells can easily be obtained in a fed-batch system using ica+ but not with ica- isolates.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e9549}, pmid = {32742809}, issn = {2167-8359}, abstract = {UNLABELLED: Staphylococcus epidermidis is one of the major opportunistic bacterial pathogens in healthcare facilities, mainly due to its strong ability to form biofilms in the surface of indwelling medical devices. To study biofilms under in vitro conditions, both fed-batch and flow systems are widely used, with the first being the most frequent due to their low cost and ease of use.

AIM: To assess if a fed-batch system previously developed to obtain biofilm released cells (Brc) from strong biofilm producing S. epidermidis isolates could also be used to obtain and characterize Brc from isolates with lower abilities to form biofilms.

METHODOLOGY: The applicability of a fed-batch system to obtain Brc from biofilms of 3 ica [+] and 3 ica [-] isolates was assessed by quantifying the biofilm and Brc biomass by optical density (OD) and colony-forming units (CFU) measurements. The effect of media replacement procedures of fed-batch systems on the amount of biofilm was determined by quantifying the biofilm and biofilm bulk fluid, by CFU, after consecutive washing steps.

RESULTS: The fed-batch model was appropriate to obtain Brc from ica[+] isolates, that presented a greater ability to form biofilms and release cells. However, the same was not true for ica [-] isolates, mainly because the washing procedure would physically remove a significant number of cells from the biofilm.

CONCLUSIONS: This study demonstrates that a fed-batch system is only feasible to be used to obtain Brc from S. epidermidis when studying strong and cohesive biofilm-forming isolates.}, } @article {pmid32742608, year = {2020}, author = {Kadkhoda, H and Ghalavand, Z and Nikmanesh, B and Kodori, M and Houri, H and Taghizadeh Maleki, D and Karimi Bavandpour, A and Eslami, G}, title = {Characterization of biofilm formation and virulence factors of Staphylococcus aureus isolates from paediatric patients in Tehran, Iran.}, journal = {Iranian journal of basic medical sciences}, volume = {23}, number = {5}, pages = {691-698}, pmid = {32742608}, issn = {2008-3866}, abstract = {OBJECTIVES: Staphylococcus aureus can cause several infections. Its capability to form biofilm has been reported to be a vital property involved in the bacteria's pathogenesis. Various genes contributing to biofilm formation have not yet been completely clarified. This study was designed to evaluate the factors influencing adherence and biofilm formation in S. aureus isolated from paediatric patients.

MATERIALS AND METHODS: One hundred and ninety-seven S. aureus isolates were obtained from pediatric patients and confirmed with phenotypic and molecular examinations. Antimicrobial susceptibility testing and biofilm formation were evaluated using standard methods. The genes encoding adhesion and virulence factors were investigated by the PCR method.

RESULTS: The most efficient antibiotics against S. aureus isolates were vancomycin and linezolid. Approximately, 54.2% of MSSA and 85.6% of MRSA isolates were biofilm producers according to the microtiter test. Our analysis indicated that MRSA isolates are better able to form biofilm compared with MSSA isolates. All isolates harbored clfA, fnbpA, icaA, icaB, icaC, and icaD, while clfB, fnbB, hlg, and pvl were detected in 99.5%, 42.1%, 97.5%, and 5.6% of isolates, respectively. In addition, a significant difference was found in fnhB gene and biofilm formation.

CONCLUSION: Our findings showed a significant correlation between mecA and pvl genes and MRSA and biofilm formation in S. aureus isolates. Additionally, this study indicated the significant role of the fnhB gene as a major marker for S. aureus biofilm formation. Therefore, further experiments are warranted to exactly elucidate the function of the fnhB gene in the formation of biofilm.}, } @article {pmid32740359, year = {2020}, author = {Pai, AB and McGuire, MD and Davidge, KN and Dean, MC and Costello, GM and Souza, E and Mukherjee, S and Heung, M and Yevzlin, AS and Yessayan, LT}, title = {Lipoteichoic Acid as a Potential Noninvasive Biomarker of Biofilm in Dialysis Access.}, journal = {ASAIO journal (American Society for Artificial Internal Organs : 1992)}, volume = {66}, number = {8}, pages = {960-965}, doi = {10.1097/MAT.0000000000001091}, pmid = {32740359}, issn = {1538-943X}, mesh = {Aged ; Arteriovenous Shunt, Surgical/adverse effects ; *Biofilms ; Biomarkers/*blood ; Central Venous Catheters/adverse effects/*microbiology ; Female ; Gram-Positive Bacterial Infections/*blood/diagnosis ; Humans ; Lipopolysaccharides/*blood ; Male ; Middle Aged ; Pilot Projects ; Prosthesis-Related Infections/*blood/diagnosis ; Renal Dialysis/adverse effects/instrumentation/methods ; Teichoic Acids/*blood ; Treatment Outcome ; }, abstract = {Tunneled central venous catheters (TCVCs) are colonized by Gram-positive organisms and form biofilm. Lipoteichoic acid (LTA) is a Gram-positive cell wall component that can be measured in serum. The purpose of this pilot study was to characterize LTA concentrations in hemodialysis (HD) patients with TCVCs compared to other access types and to evaluate biofilm morphology and microbiology in TCVCs removed by clinical decision. The study enrolled patients with TCVCs (18), grafts (19), and fistulas (18). Blood samples were collected before HD, at 30 minutes, 2 hours, and end of HD. Catheters removed by clinical decision were evaluated by scanning electron microscopy (SEM) for biofilm morphology, and portions of the catheter were cultured. LTA was detectable in all samples and concentrations increased significantly in all access types during HD (p < 0.05 for all comparisons). Patients with TCVCs that had a >30% increase in LTA concentration from baseline also had the greatest rate of increase (slope) compared to grafts and fistulas (p = 0.03 and p = 0.04, respectively). Catheters removed by clinical decision (n = 7) and examined by SEM had deposition of fibrin. Cultures revealed polymicrobial colonization. TCVCs had the highest rate of increase of LTA during HD. Further studies to determine the source of LTA in patients with AVG and AVF are warranted.}, } @article {pmid32739870, year = {2020}, author = {D'Andrea, MM and Lau, GW}, title = {DNABII targeting antibodies as vaccines against biofilm diseases.}, journal = {EBioMedicine}, volume = {58}, number = {}, pages = {102921}, pmid = {32739870}, issn = {2352-3964}, support = {R01 HL090699/HL/NHLBI NIH HHS/United States ; R01 HL142626/HL/NHLBI NIH HHS/United States ; }, mesh = {Antibodies ; Bacterial Proteins ; *Biofilms ; Humans ; *Vaccines ; }, } @article {pmid32737867, year = {2020}, author = {Ventura, RF and Galdino, ACM and Viganor, L and Schuenck, RP and Devereux, M and McCann, M and Santos, ALS and Nunes, APF}, title = {Antimicrobial action of 1,10-phenanthroline-based compounds on carbapenemase-producing Acinetobacter baumannii clinical strains: efficacy against planktonic- and biofilm-growing cells.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {4}, pages = {1703-1710}, pmid = {32737867}, issn = {1678-4405}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/growth & development/isolation & purification/metabolism ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects/growth & development ; Carbapenems/pharmacology ; Copper/chemistry/pharmacology ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; Phenanthrolines/chemistry/*pharmacology ; Silver/chemistry/pharmacology ; beta-Lactamases/*metabolism ; }, abstract = {Therapeutic options are limited for patients infected with Acinetobacter baumannii due to its multidrug-resistance profile. So, the search for new antimicrobials against this gram-negative bacterial pathogen has become a worldwide priority. The present study aimed to evaluate the effects of 1,10-phenanthroline (phen), 1,10-phenanthroline-5,6-dione (phendione), [Ag(phendione)2]ClO4 (Ag-phendione) and [Cu(phendione)3](ClO4)2·4H2O (Cu-phendione) on 26 carbapenemase-producing A. baumannii strains. The susceptibility to carbapenems was performed by detecting the metallo-beta-lactamase (MBL) genes by PCR and by determining the MIC. Also, disk diffusion method was applied to evaluate the susceptibility to other antimicrobial classes. The test compounds were evaluated on both planktonic- and biofilm-growing bacterial cells. The results revealed that all A. baumannii strains had the intrinsic blaoxa-51 gene, and at least one of the blaoxa-23 or blaoxa-24 genes. The geometric mean MIC and minimum bactericidal concentration (MBC) values, respectively, were as follows: Cu-phendione (1.56 and 2.30 μM), Ag-phendione (2.48 and 3.63 μM), phendione (9.44 and 9.70 μM), and phen (70.46 and 184.28 μM). The test compounds (at 0.5 × MIC) affected the biofilm formation and disrupted the mature biofilm, in a typically dose-dependent manner, reducing biomass and viability parameters. Collectively, silver and copper-phendione derivatives presented potent antimicrobial action against planktonic- and biofilm-forming cells of carbapenemase-producing A. baumannii.}, } @article {pmid32737484, year = {2020}, author = {Yin, Q and Wu, S and Wu, L and Wang, Z and Mu, Y and Zhang, R and Dong, C and Zhou, B and Zhao, B and Zheng, J and Sun, Y and Cheng, X and Yang, L}, title = {A novel in silico antimicrobial peptide DP7 combats MDR Pseudomonas aeruginosa and related biofilm infections.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {75}, number = {11}, pages = {3248-3259}, doi = {10.1093/jac/dkaa308}, pmid = {32737484}, issn = {1460-2091}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Computer Simulation ; Mice ; Microbial Sensitivity Tests ; Pore Forming Cytotoxic Proteins ; *Pseudomonas Infections/drug therapy ; *Pseudomonas aeruginosa ; }, abstract = {BACKGROUND: Antimicrobial peptides are promising alternative antimicrobial agents to combat MDR. DP7, an antimicrobial peptide designed in silico, possesses broad-spectrum antimicrobial activities and immunomodulatory effects. However, the effects of DP7 against Pseudomonas aeruginosa and biofilm infection remain largely unexplored.

OBJECTIVES: To assess (i) the antimicrobial activity of DP7 against MDR P. aeruginosa; and (ii) the antibiofilm activity against biofilm infection. Also, to preliminarily investigate the possible antimicrobial mode of action.

METHODS: The MICs of DP7 for 104 clinical P. aeruginosa strains (including 57 MDR strains) and the antibiofilm activity were determined. RNA-Seq, genome sequencing and cell morphology were conducted. Both acute and chronic biofilm infection mouse models were established. Two mutants, resulting from point mutations associated with LPS and biofilms, were constructed to investigate the potential mode of action.

RESULTS: DP7, at 8-32 mg/L, inhibited the growth of clinical P. aeruginosa strains and, at 64 mg/L, reduced biofilm formation by 43% to 68% in vitro. In acute lung infection, 0.5 mg/kg DP7 exhibited a 70% protection rate and reduced bacterial colonization by 50% in chronic infection. DP7 mainly suppressed gene expression involving LPS and outer membrane proteins and disrupted cell wall structure. Genome sequencing of the DP7-resistant strain DP7R revealed four SNPs controlling LPS and biofilm production. gshA44 and wbpJ139 mutants displayed LPS reduction and motility deficiency, conferring the reduction of LPS and biofilm biomass of strain DP7R and indicating that LPS was a potential target of DP7.

CONCLUSIONS: These results demonstrate that DP7 may hold potential as an effective antimicrobial agent against MDR P. aeruginosa and related infections.}, } @article {pmid32737303, year = {2020}, author = {Obana, N and Nakamura, K and Nomura, N}, title = {Temperature-regulated heterogeneous extracellular matrix gene expression defines biofilm morphology in Clostridium perfringens.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {29}, pmid = {32737303}, issn = {2055-5008}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Clostridium perfringens/*physiology ; Extracellular Polymeric Substance Matrix/*genetics ; Gene Expression Regulation, Bacterial ; Temperature ; }, abstract = {Cells in biofilms dynamically adapt to surrounding environmental conditions, which alters biofilm architecture. The obligate anaerobic pathogen Clostridium perfringens shows different biofilm structures in different temperatures. Here we find that the temperature-regulated production of extracellular polymeric substance (EPS) is necessary for morphological changes in biofilms. We identify BsaA proteins as an EPS matrix necessary for pellicle biofilm formation at lower temperature and find that extracellularly secreted BsaA protein forms filamentous polymers. We show that sipW-bsaA operon expression is bimodal, and the EPS-producing population size is increased at a lower temperature. This heterogeneous expression of the EPS gene requires a two-component system. We find that EPS-producing cells cover EPS-nonproducing cells attaching to the bottom surface. In the deletion mutant of pilA2, encoding a type IV pilin, the EPS gene expression is ON in the whole population. This heterogeneity is further regulated by the cleavage of the pilA2 mRNA by RNase Y, causing temperature-responsive EPS expression in biofilms. As temperature is an environmental cue, C. perfringens may modulate EPS expression to induce morphological changes in biofilm structure as a strategy for adapting to interhost and external environments.}, } @article {pmid32736723, year = {2020}, author = {Anandkumar, B and George, RP and Philip, J}, title = {Efficacy of imidazolium and piperidinium based ionic liquids on inhibiting biofilm formation on titanium and carbon steel surfaces.}, journal = {Analytica chimica acta}, volume = {1126}, number = {}, pages = {38-51}, doi = {10.1016/j.aca.2020.05.072}, pmid = {32736723}, issn = {1873-4324}, abstract = {In the present study, the efficacies of three different cationic and anionic ionic liquids (ILs) on biofilm formation on materials used in cooling water systems were evaluated. Two imidazolium based ILs; 1-Ethyl 3-Methylimidazolium tetrafluoroborate - (IL-E) and 1-Butyl-3-methylimidazolium chloride - (IL-I) with anionic fluoride and chloride groups and one piperidinium based IL, N-methyl-N-propylpiperidinium bis(trifluoromethylsulfonyl)imide - (IL-M) with fluoromethyl group as anion were used. The efficacy of these ILs were evaluated on planktonic and sessile cells of major biofilm formers in cooling water systems using Gram negative bacterium Pseudomonas sp. and Gram positive bacterium Bacillus sp. Further their effect on inhibiting biofilm formation on titanium and carbon steel surfaces were also evaluated. Results showed that planktonic cells of Pseudomonas sp. and Bacillus sp. were effectively inhibited by 25 ppm of IL-M and IL-E, respectively. For both bacteria, 50 ppm of IL-I was enough to inhibit and eradicate the sessile cell formation. Among the three ILs, IL-E was the best in inhibiting the adhesion of bacterial cells on Ti and CS surfaces. These results suggest that Imidazolium based ILs are effective in controlling sessile cell formation and eradicating mature biofilm as compared to piperidinium based IL. Further, Imidazolium based IL with fluoride anion (IL-E) was the best in inhibiting adhesion of these bacterial cells and thereby biofilm formation on material surfaces. This study establishes the feasibility of using ILs in cooling water system for bacterial biofilm control along with other conventional biofouling control methods.}, } @article {pmid32736143, year = {2020}, author = {Martins, ML and Ribeiro-Lages, MB and Masterson, D and Magno, MB and Cavalcanti, YW and Maia, LC and Fonseca-Gonçalves, A}, title = {Efficacy of natural antimicrobials derived from phenolic compounds in the control of biofilm in children and adolescents compared to synthetic antimicrobials: A systematic review and meta-analysis.}, journal = {Archives of oral biology}, volume = {118}, number = {}, pages = {104844}, doi = {10.1016/j.archoralbio.2020.104844}, pmid = {32736143}, issn = {1879-1506}, mesh = {Adolescent ; *Anti-Infective Agents ; Biofilms/*drug effects ; Biological Products/*pharmacology ; Child ; Humans ; Mouth/microbiology ; Phenols/*pharmacology ; Streptococcus mutans/drug effects ; }, abstract = {AIM: To evaluate the efficacy of natural antimicrobials derived from phenolic compounds (NAPs), compared to synthetic antimicrobials (SAs), in the biofilm control and microorganisms (MOs) count among children and adolescents at different intervention times through a systematic review and meta-analysis.

METHODS: Electronic searches were carried out in PubMed, Scopus, Cochrane Library, Web of Science, VHL, and Grey Literature. Randomized and non-randomized clinical trials were included. Methodological quality and risk of bias were assessed using the tools ROBINS-I and RoB 2.0. Meta-analyses (MAs) were performed according to three parameters: the influence of NAPs on the plaque index (PI) mean; the period of NAPs administration (≤15 days/>15 days) on the biofilm reduction; and the influence of NAPs on the MOs count subgrouping according to the type of MO (total MOs, S. mutans, and Streptococcus spp.). The standard mean differences were calculated (p ≤ 0.05) for all analyses, and the heterogeneity was tested through the I[2] index. The evidence was certainty-tested using the GRADE approach.

RESULTS: Sixteen studies were selected for qualitative synthesis, and 12 studies were included in the MAs. NAPs were less efficacious in improving the PI (p < 0.0001, I[2]>87 %) and reducing biofilm over time (p < 0.01, I[2]>87 %) but presented a reduction in MOs count similar to that of SAs (p = 0.3, I[2] = 0%). The quality of the evidence ranged from moderate to low.

CONCLUSION: Although the use of NAPs is similar to the use of SAs in reducing MOs count, it is less effective than SAs in improving PI mean and for biofilm reduction over time.}, } @article {pmid32736020, year = {2020}, author = {Ghodake, V and Vishwakarma, J and Vavilala, SL and Patravale, V}, title = {Cefoperazone sodium liposomal formulation to mitigate P. aeruginosa biofilm in Cystic fibrosis infection: A QbD approach.}, journal = {International journal of pharmaceutics}, volume = {587}, number = {}, pages = {119696}, doi = {10.1016/j.ijpharm.2020.119696}, pmid = {32736020}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Cefoperazone ; *Cystic Fibrosis/drug therapy ; Extracellular Polymeric Substance Matrix ; Humans ; Liposomes ; *Pseudomonas Infections ; Pseudomonas aeruginosa ; }, abstract = {Cystic fibrosis (CF), an atypical genetic disorder, develops due to mutations in cystic fibrosis transmembrane conductance regulator gene, which consequently leads to infection and inflammation. CF infections are commonly characterized by the presence of an extracellular polymeric substance (EPS) matrix or the 'biofilm', which presents an entry barrier for the antibiotics. The current research work focuses on systematic Quality by Design based development of cefoperazone sodium loaded liposome formulation. DPPC and cholesterol containing liposomes were formulated by using 'thin film hydration' method. The freeze drying and further characterization of optimized formulation was carried out for particle size distribution, % entrapment efficiency, FTIR, DSC and pXRD. The IC50 value of the formulation (0.42 μg/ml) was found to be half of that of the drug (0.92 μg/ml). The formulation showed 50% biofilm inhibition and eradication at ~1 μg/ml. The cell surface hydrophobicity was reduced to ~50% at MIC value of the formulation while it was 78% for the control. The EPS component of P. aeruginosa biofilm reduced to 17% after treatment with 0.42 μg/ml formulation. The effect of formulation on biofilm was further confirmed by SEM analysis which revealed that the biofilm was disintegrated on treatment with 0.42 μg/ml of formulation.}, } @article {pmid32734981, year = {2020}, author = {Liu, L and Ge, C and Zhang, Y and Ma, W and Su, X and Chen, L and Li, S and Wang, L and Mu, X and Xu, Y}, title = {Tannic acid-modified silver nanoparticles for enhancing anti-biofilm activities and modulating biofilm formation.}, journal = {Biomaterials science}, volume = {8}, number = {17}, pages = {4852-4860}, doi = {10.1039/d0bm00648c}, pmid = {32734981}, issn = {2047-4849}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; *Silver/pharmacology ; Tannins ; }, abstract = {The formation of bacterial biofilms is a key factor in the emergence of chronic infections due to the strong resistance of biofilms to conventional antibiotics. There is an urgent need to develop an effective strategy to control the formation of biofilms. In this study, a nanocomposite of tannic acid and silver (Tannin-AgNPs) was designed and successfully prepared based on the quorum sensing (QS) inhibitory activity of tannic acid and the anti-bacterial activity of silver. The dynamic light scattering and SEM observations indicated that the obtained Tannin-AgNPs were spherical with a mean particle size of 42.37 nm. Tannic acid was successfully modified on the surface of silver nanoparticles and characterized via Fourier transform infrared (FTIR) spectroscopy. The prepared Tannin-AgNPs demonstrated a more effective anti-bacterial and anti-biofilm activity against E. coli than the unmodified AgNPs or tannic acid. In addition, the Tannin-AgNPs can modulate the formation process of E. coli biofilms, shorten the growth period of biofilms and extend the dispersion period of biofilms. Tannin-AgNPs also showed the function of decreasing the production of the QS signal molecule. The proposed strategy of constructing a nanocomposite using AgNPs and natural components with QS inhibitory activity is effective and promising for inhibiting the formation of biofilms.}, } @article {pmid32734273, year = {2020}, author = {Kim, SY and Kang, SS}, title = {Anti-Biofilm Activities of Manuka Honey against Escherichia coli O157:H7.}, journal = {Food science of animal resources}, volume = {40}, number = {4}, pages = {668-674}, pmid = {32734273}, issn = {2636-0780}, abstract = {Manuka honey (MH) has been shown anti-bacterial activity against several pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation by Escherichia coli O157:H7 has not yet been examined. In this study, MH significantly reduced E. coli O157:H7 biofilm. Moreover, pre- and post-treatment with MH also significantly reduced E. coli O157:H7 biofilm. Cellular metabolic activities exhibited that the viability of E. coli O157:H7 biofilm cells was reduced in the presence of MH. Further, colony forming unit of MH-treated E. coli O157:H7 biofilm was significantly reduced by over 70%. Collectively, this study suggests the potential of anti-biofilm properties of MH which could be applied to control E. coli O157:H7.}, } @article {pmid32731889, year = {2020}, author = {Eydou, Z and Jad, BN and Elsayed, Z and Ismail, A and Magaogao, M and Hossain, A}, title = {Investigation on the effect of vitamin C on growth & biofilm-forming potential of Streptococcus mutans isolated from patients with dental caries.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {231}, pmid = {32731889}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/pharmacology ; Ascorbic Acid/*pharmacology ; Biofilms/*drug effects/growth & development ; Dental Caries/*microbiology ; Humans ; Kinetics ; Microbial Sensitivity Tests ; Streptococcus mutans/*drug effects/growth & development/isolation & purification ; Vitamins/*pharmacology ; }, abstract = {BACKGROUND: Streptococcus mutans is a major cause of dental caries. Its capacity to produce biofilm is fundamental in the pathogenesis of this ubiquitous condition. As maintaining a healthy dentition is a genuine goal given the contemporary advance in caries control, researchers are striving to achieve a breakthrough in caries therapy. We are taking the anti-cariogenic properties of vitamin C a step-further, considering the well-known evidence of the inversely proportionate relationship between salivary levels of vitamin C and dental caries. The aim of this study was to determine MIC, MBC, biofilm prevention concentration (BPC), and derivative measures of vitamin C against fresh clinical isolates of S. mutans to evaluate its efficacy as an anti-cariogenic agent.

RESULTS: Based on the data of four independent experiments done in quadruplicates, we found a concentration-dependent inhibitory effect of vitamin C on all S. mutans strains tested. The average MBC, MIC, and BPC of vitamin C were found to be 10.16, 9.38, and 5.61 mg/ml, respectively. Spectrophotometric quantitation of crystal violet showed diminished biofilm formation in the presence of vitamin C (p < 0.05). When compared with gentamicin, vitamin C produced a zone of inhibition that was three times as large against the clinical isolates.

CONCLUSION: Our results show that vitamin C has a negative effect on S. mutans growth and biofilm formation. Being the first to meticulously utilize BPC to explore a well-known effect of vitamin C, this report aims to help in the instigation of trials of higher evidence that will ultimately culminate in repurposing vitamin C as a novel anti-cariogenic agent, albeit further studies are required to provide auxiliary evidence in this context.}, } @article {pmid32730885, year = {2020}, author = {Galvão, FO and Dantas, FGDS and Santos, CRL and Marchioro, SB and Cardoso, CAL and Wender, H and Sangalli, A and Almeida-Apolonio, AA and Oliveira, KMP}, title = {Cochlospermum regium (Schrank) pilger leaf extract inhibit methicillin-resistant Staphylococcus aureus biofilm formation.}, journal = {Journal of ethnopharmacology}, volume = {261}, number = {}, pages = {113167}, doi = {10.1016/j.jep.2020.113167}, pmid = {32730885}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; *Bixaceae/chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development/ultrastructure ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Plant Extracts/isolation & purification/*pharmacology ; Plant Leaves/chemistry ; }, abstract = {Cochlospermum regium, known as "algodãozinho", is an important plant belonging to Brazilian biodiversity used in traditional medicine to treat infections, wounds and skin conditions.

AIM OF THE STUDY: To assess the effects of aqueous and ethanolic extracts from C. regium leaves on methicillin-resistant Staphylococcus aureus planktonic cells and biofilm formation.

MATERIAL AND METHODS: The phytochemical characterization of the extracts was carried out by quantification of flavonoids, phenols and tannins and HPLC-DAD. Minimum inhibitory concentrations, cell viability, and enzyme activity inhibition were determined in planktonic cells exposed to C. regium extracts. The effect of the extracts on biofilms was assessed by quantifying colony-forming units (CFUs) and the extracellular matrix, and by visualizing the biofilm structure using scanning electron microscopy.

RESULTS: Leaf extract contents showed high concentration of phenols and the gallic and ellagic acids were identified. The extracts showed potent antimicrobial activities at concentrations ranging from 62.5-250 μg/mL, and decreased coagulase activity. In addition, the extracts prevented biofilm formation, and the aqueous extract completely inhibited its formation.

CONCLUSIONS: C. regium extracts stand out as promising alternative treatments for the prevention and treatment of methicillin-resistant Staphylococcus aureus infections.}, } @article {pmid32730867, year = {2020}, author = {Kanchanapiboon, J and Kongsa, U and Pattamadilok, D and Kamponchaidet, S and Wachisunthon, D and Poonsatha, S and Tuntoaw, S}, title = {Boesenbergia rotunda extract inhibits Candida albicans biofilm formation by pinostrobin and pinocembrin.}, journal = {Journal of ethnopharmacology}, volume = {261}, number = {}, pages = {113193}, doi = {10.1016/j.jep.2020.113193}, pmid = {32730867}, issn = {1872-7573}, mesh = {Actins/genetics/metabolism ; Amphotericin B/pharmacology ; Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/genetics/growth & development ; Dose-Response Relationship, Drug ; Flavanones/isolation & purification/*pharmacology ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal ; *Zingiberaceae/chemistry ; }, abstract = {Boesenbergia rotunda (L.) Mansf. (Zingiberaceae) is an indigenous plant of Southeast Asia. Based on ethnopharmacological use, the rhizome is recommended in the treatment of stomachache, leukoplakia, abscesses, and leukorrhea in Thailand primary health care system. Candida albicans often causes leukorrhea, and infection of many mucosal sites. Its infection leads to serious illness.

AIM OF THE STUDY: This study aimed to investigate the effects of the ethanolic extract of the B. rotunda rhizome on C. albicans ATCC10231 in the stages of planktonic and biofilm formation and to explore the underlying mechanisms.

MATERIALS AND METHODS: The chemical composition of the extract was determined using ultra-performance liquid chromatography (UPLC). The planktonic growth of C. albicans was evaluated by the microdilution method, following EUCAST guidelines. For each stage of biofilm formation, the biofilm was assessed by the MTT assay. The biofilm structure was examined under a light microscope. The degree of cell surface hydrophobicity was measured. The mRNA levels of ALS1, ALS3, and ACT1 were determined by RT-qPCR.

RESULTS: The extract of B. rotunda consisted of 25% (w/w) pinostrobin and 12% (w/w) pinocembrin. All stages of C. albicans biofilm formation were significantly inhibited by the extract, whereas the planktonic growth did not change. Biofilm development greatly decreased due to the extract in a concentration-dependent manner, with an IC50 value of 17.7 μg/mL. Pinostrobin and pinocembrin demonstrated inhibitory effects during this stage. These results were in accordance with the microscopic evaluation. The filamentous form decreased with pinocembrin rather than pinostrobin. Moreover, the cell surface hydrophobicity was significantly decreased by 6.25 and 12.5 μg/mL of the extract and 100 μM of pinocembrin. The ALS3 mRNA level was noticeably decreased by 12.5 μg/mL of the extract, 100 μM of pinostrobin, and 100 μM of pinocembrin. The ACT1 mRNA level decreased significantly with pinocembrin. However, the ALS1 mRNA level was not altered following all treatments.

CONCLUSION: The ethanolic extract of B. rotunda could inhibit biofilm formation of C. albicans, especially during the biofilm development stage, by means of reducing the cell surface hydrophobicity and suppressing the ALS3 mRNA expression. Pinocembrin had a stronger effect on ALS3 mRNA expression than pinostrobin. Only pinocembrin significantly decreased the ACT1 mRNA level.}, } @article {pmid32730363, year = {2020}, author = {Mallick, I and Kirtania, P and Szabó, M and Bashir, F and Domonkos, I and Kós, PB and Vass, I}, title = {A simple method to produce Synechocystis PCC6803 biofilm under laboratory conditions for electron microscopic and functional studies.}, journal = {PloS one}, volume = {15}, number = {7}, pages = {e0236842}, pmid = {32730363}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Cell Membrane/*metabolism/ultrastructure ; Microscopy, Electron, Scanning/*methods ; Polysaccharides, Bacterial/*metabolism/ultrastructure ; Synechocystis/*growth & development/metabolism/*ultrastructure ; }, abstract = {Cyanobacteria can form biofilms in nature, which have ecological roles and high potential for practical applications. In order to study them we need biofilm models that contain healthy cells and can withstand physical manipulations needed for structural studies. At present, combined studies on the structural and physiological features of axenic cyanobacterial biofilms are limited, mostly due to the shortage of suitable model systems. Here, we present a simple method to establish biofilms using the cyanobacterium Synechocystis PCC6803 under standard laboratory conditions to be directly used for photosynthetic activity measurements and scanning electron microscopy (SEM). We found that glass microfiber filters (GMF) with somewhat coarse surface features provided a suitable skeleton to form Synechocystis PCC6803 biofilms. Being very fragile, untreated GMFs were unable to withstand the processing steps needed for SEM. Therefore, we used polyhydroxybutyrate coating to stabilize the filters. We found that up to five coats resulted in GMF stabilization and made possible to obtain high resolution SEM images of the structure of the surface-attached cells and the extensive exopolysaccharide and pili network, which are essential features of biofilm formation. By using pulse-amplitude modulated variable chlorophyll fluorescence imaging, it was also demonstrated that the biofilms contain photosynthetically active cells. Therefore, the Synechocystis PCC6803 biofilms formed on coated GMFs can be used for both structural and functional investigations. The model presented here is easy to replicate and has a potential for high-throughput studies.}, } @article {pmid32730291, year = {2020}, author = {Vyas, N and Sammons, RL and Kuehne, SA and Johansson, C and Stenport, V and Wang, QX and Walmsley, AD}, title = {The effect of standoff distance and surface roughness on biofilm disruption using cavitation.}, journal = {PloS one}, volume = {15}, number = {7}, pages = {e0236428}, pmid = {32730291}, issn = {1932-6203}, mesh = {*Biofilms ; Dental Implants/microbiology ; Image Processing, Computer-Assisted ; Surface Properties ; Time Factors ; Ultrasonics ; }, abstract = {Effective biofilm removal from surfaces in the mouth is a clinical challenge. Cavitation bubbles generated around a dental ultrasonic scaler are being investigated as a method to remove biofilms effectively. It is not known how parameters such as surface roughness and instrument distance from biofilm affect the removal. We grew Strepotococcus sanguinis biofilms on coverslips and titanium discs with varying surface roughness (between 0.02-3.15 μm). Experimental studies were carried out for the biofilm removal using high speed imaging and image analysis to calculate the area of biofilm removed at varying ultrasonic scaler standoff distances from the biofilm. We found that surface roughness up to 2 μm does not adversely affect biofilm removal but a surface roughness of 3 μm caused less biofilm removal. The standoff distance also has different effects depending on the surface roughness but overall a distance of 1 mm is just as effective as a distance of 0.5 mm. The results show significant biofilm removal due to an ultrasonic scaler tip operating for only 2s versus 15-60s in previous studies. The technique developed for high speed imaging and image analysis of biofilm removal can be used to investigate physical biofilm disruption from biomaterial surfaces in other fields.}, } @article {pmid32727033, year = {2020}, author = {Špacapan, M and Danevčič, T and Štefanic, P and Porter, M and Stanley-Wall, NR and Mandic-Mulec, I}, title = {The ComX Quorum Sensing Peptide of Bacillus subtilis Affects Biofilm Formation Negatively and Sporulation Positively.}, journal = {Microorganisms}, volume = {8}, number = {8}, pages = {}, pmid = {32727033}, issn = {2076-2607}, support = {P4-0116//Javna Agencija za Raziskovalno Dejavnost RS/ ; J4-9302//Javna Agencija za Raziskovalno Dejavnost RS/ ; "Young Researcher Grant"//Javna Agencija za Raziskovalno Dejavnost RS/ ; BB/M013774//BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N022254/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Quorum sensing (QS) is often required for the formation of bacterial biofilms and is a popular target of biofilm control strategies. Previous studies implicate the ComQXPA quorum sensing system of Bacillus subtilis as a promoter of biofilm formation. Here, we report that ComX signaling peptide deficient mutants form thicker and more robust pellicle biofilms that contain chains of cells. We confirm that ComX positively affects the transcriptional activity of the PepsA promoter, which controls the synthesis of the major matrix polysaccharide. In contrast, ComX negatively controls the PtapA promoter, which drives the production of TasA, a fibrous matrix protein. Overall, the biomass of the mutant biofilm lacking ComX accumulates more monosaccharide and protein content than the wild type. We conclude that this QS phenotype might be due to extended investment into growth rather than spore development. Consistent with this, the ComX deficient mutant shows a delayed activation of the pre-spore specific promoter, PspoIIQ, and a delayed, more synchronous commitment to sporulation. We conclude that ComX mediated early commitment to sporulation of the wild type slows down biofilm formation and modulates the coexistence of multiple biological states during the early stages of biofilm development.}, } @article {pmid32725561, year = {2020}, author = {Mohammed, AN and Radi, AM and Khaled, R and Abo El-Ela, FI and Kotp, AA}, title = {Exploitation of new approach to control of environmental pathogenic bacteria causing bovine clinical mastitis using novel anti-biofilm nanocomposite.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {34}, pages = {42791-42805}, doi = {10.1007/s11356-020-10054-1}, pmid = {32725561}, issn = {1614-7499}, mesh = {Animals ; Biofilms ; Cattle ; Escherichia coli ; Female ; Mice ; *Nanocomposites ; Spectroscopy, Fourier Transform Infrared ; *Staphylococcus aureus ; }, abstract = {New approaches are required for prevention and control of biofilm-producing bacteria and consequently mitigating the health problems of bovine clinical mastitis. This work designed to determine prevalence rates of biofilm-producing bacteria that causing bovine clinical mastitis and evaluate the anti-biofilm effectiveness of novel nanocomposite of zinc-aluminum layered double hydroxide intercalated with gallic acid (GA) as chelating agent (Zn-Al LDH/GA) on the prevention and control of environmental pathogenic bacteria; Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus), and Coagulase-negative staphylococci (CNS), besides Listeria monocytogenes (L. monocytogenes) and assess the ability to use as an antimicrobial agent, and/or sanitizer for milking equipment. All samples (n = 230) involved clinical mastitis cow's milk (n = 50) beside environmental samples (n = 180) were collected then examined for isolation and identification of bacterial pathogens. Zn-Al LDH/GA nanocomposite was synthesized using co-precipitation method, then characterized by Fourier-transform infrared spectroscopy (FT-IR); X-ray diffraction (XRD); field emission scanning electron microscopy (FESEM); high-resolution transmission electron microscopy (HRTEM); thermogravimetric analysis (TGA); differential thermal analysis (DTA); zeta potential; DLS analysis; and Brunauer, Emmett, and Teller (BET) surface area. The anti-biofilm activity of nanocomposite against mastitis-causing bacteria was detected using the broth micro-dilution and disc-diffusion assay. Results, the minimum concentration of Zn-Al LDH/GA that inhibited the growth of gram-positive and negative bacteria, were 312-625 and 5000 μg/mL, respectively. The LD50 of Zn-Al LDH/GA was determined in mice at 1983.3 mg/kg b.wt. As a conclusion, Zn-Al LDH/GA nanocomposite proved its efficiency as an antimicrobial agent and/or sanitizer used for cleaning of milking equipment, due to it could inhibit the growth and multiplication of potentially pathogenic bacteria that causing clinical mastitis and its formation of biofilm on the milking equipment. Zn-Al LDH/GA was found to use under varying pH conditions compared with other commercial sanitizer used besides the formation of nanocomposite increases the material stability.}, } @article {pmid32724094, year = {2020}, author = {Furner-Pardoe, J and Anonye, BO and Cain, R and Moat, J and Ortori, CA and Lee, C and Barrett, DA and Corre, C and Harrison, F}, title = {Anti-biofilm efficacy of a medieval treatment for bacterial infection requires the combination of multiple ingredients.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {12687}, pmid = {32724094}, issn = {2045-2322}, support = {MR/N014294/1/MRC_/Medical Research Council/United Kingdom ; 17/0005690/DUK_/Diabetes UK/United Kingdom ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Bacterial Infections/microbiology/*prevention & control ; Biofilms/*drug effects/growth & development ; Garlic/*chemistry ; Humans ; Microbial Sensitivity Tests ; Onions/*chemistry ; Plant Extracts/isolation & purification/*pharmacology ; }, abstract = {Novel antimicrobials are urgently needed to combat drug-resistant bacteria and to overcome the inherent difficulties in treating biofilm-associated infections. Studying plants and other natural materials used in historical infection remedies may enable further discoveries to help fill the antibiotic discovery gap. We previously reconstructed a 1,000-year-old remedy containing onion, garlic, wine, and bile salts, known as 'Bald's eyesalve', and showed it had promising antibacterial activity. In this current paper, we have found this bactericidal activity extends to a range of Gram-negative and Gram-positive wound pathogens in planktonic culture and, crucially, that this activity is maintained against Acinetobacter baumannii, Stenotrophomonas maltophilia, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pyogenes in a soft-tissue wound biofilm model. While the presence of garlic in the mixture can explain the activity against planktonic cultures, garlic has no activity against biofilms. We have found the potent anti-biofilm activity of Bald's eyesalve cannot be attributed to a single ingredient and requires the combination of all ingredients to achieve full activity. Our work highlights the need to explore not only single compounds but also mixtures of natural products for treating biofilm infections and underlines the importance of working with biofilm models when exploring natural products for the anti-biofilm pipeline.}, } @article {pmid32724037, year = {2020}, author = {Flores-Valdez, MA and Aceves-Sánchez, MJ and Peterson, EJR and Baliga, N and Bravo-Madrigal, J and De la Cruz-Villegas, MÁ and Ares, MA and Born, S and Voskuil, M and Pérez-Padilla, NA and Burciaga-Flores, M and Camacho-Villegas, TA and Espinoza-Jorge, MG}, title = {Transcriptional portrait of M. bovis BCG during biofilm production shows genes differentially expressed during intercellular aggregation and substrate attachment.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {12578}, pmid = {32724037}, issn = {2045-2322}, mesh = {BCG Vaccine/genetics/metabolism ; Bacterial Adhesion ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Mycobacterium bovis/*genetics/metabolism ; Mycobacterium tuberculosis/*genetics/physiology ; Operon ; Regulon ; Transcription, Genetic ; }, abstract = {Mycobacterium tuberculosis and M. smegmatis form drug-tolerant biofilms through dedicated genetic programs. In support of a stepwise process regulating biofilm production in mycobacteria, it was shown elsewhere that lsr2 participates in intercellular aggregation, while groEL1 was required for biofilm maturation in M. smegmatis. Here, by means of RNA-Seq, we monitored the early steps of biofilm production in M. bovis BCG, to distinguish intercellular aggregation from attachment to a surface. Genes encoding for the transcriptional regulators dosR and BCG0114 (Rv0081) were significantly regulated and responded differently to intercellular aggregation and surface attachment. Moreover, a M. tuberculosis H37Rv deletion mutant in the Rv3134c-dosS-dosR regulon, formed less biofilm than wild type M. tuberculosis, a phenotype reverted upon reintroduction of this operon into the mutant. Combining RT-qPCR with microbiological assays (colony and surface pellicle morphologies, biofilm quantification, Ziehl-Neelsen staining, growth curve and replication of planktonic cells), we found that BCG0642c affected biofilm production and replication of planktonic BCG, whereas ethR affected only phenotypes linked to planktonic cells despite its downregulation at the intercellular aggregation step. Our results provide evidence for a stage-dependent expression of genes that contribute to biofilm production in slow-growing mycobacteria.}, } @article {pmid32723278, year = {2020}, author = {Hortaç İştar, E and Alışkan, HE and Başustaoğlu, A}, title = {[Determination of Biofilm Formation Properties of Methicillin Sensitive and Resistant Staphylococcus aureus Isolates by Conventional and Molecular Methods].}, journal = {Mikrobiyoloji bulteni}, volume = {54}, number = {2}, pages = {223-234}, doi = {10.5578/mb.69204}, pmid = {32723278}, issn = {0374-9096}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Humans ; Methicillin/pharmacology ; *Methicillin-Resistant Staphylococcus aureus/physiology ; Microbial Sensitivity Tests ; *Staphylococcal Infections ; *Staphylococcus aureus/drug effects/physiology ; }, abstract = {Biofilm-related infections are considered as among the foremost causes of treatment failure nowadays. One of the most common causes of biofilm-related infections is Staphylococcus aureus. It becomes extremely difficult to determine the appropriate treatment protocol while biofilm-related infections are coexisting with bacterial methicillin resistance. The aim of this study was to observe the potential of biofilm formation of methicillin-sensitive and -resistant S.aureus strains isolated from different clinical specimens and to determine reliable and effective methods for biofilm detection. A total of 200 S.aureus strains (100 methicillin-resistant and 100 methicillin-susceptible) isolated from 107 wound, 93 blood and catheter specimens, which were accepted as causative agents, included in the study. In order to determine the methicillin sensitivity, oxacillin minimal inhibitory concentration value obtained by an automated system and cefoxitin disc diffusion method were evaluated together. Biofilm formation was investigated by modified Christensen (MC), MTT, BioTimer and Congo Red Agar (CRA) methods, and the presence of ica operon responsible for biofilm formation was also observed by polymerase chain reaction. It has been shown that methicillin-resistant isolates produce biofilms in a shorter time and higher rate, and their biofilm structure is denser than methicillin-sensitive isolates in all MC, MTT and BioTimer methods. There was no difference between blood and wound isolates in biofilm formation. The most sensitive and specific conventional methods were MTT and BioTimer methods respectively. There was no significant difference between the isolates containing a gene region of icaADBC operon and the biofilm forming isolates according to MC, MTT, BioTimer and CCA methods. There was a high correlation between the presence of biofilm and ica positivity, and the tendency to form biofilm augmented as the number of ica genes increased. It has been emphasized that more virulent strains such as methicillin-resistant S.aureus have a higher tendency to form biofilm, and these two resistance mechanisms have been shown to support each other as cascade. ica detection may be an important reagent in itself for the detection of virulent strains, thus detection of the ica presence may be an early marker of treatment decisions, determination of protection strategies, and struggle with biofilm-related infections. In cases where molecular methods are not available, the existence of quick, easy-to-apply and reliable conventional methods to detect biofilm formation is extremely important. All conventional methods used in this study seem to be sufficient in this respect. MC and MTT methods stand out in terms of biofilm quantitation. BioTimer method is a very new and remarkable test used to detect biofilm formation. In conclusion, determining the potential of biofilm formation of colonizing or causative agents and taking essential precautions before interventional procedures will decrease biofilm related infections and related morbidity and mortality.}, } @article {pmid32722996, year = {2020}, author = {Bose, SK and Nirbhavane, P and Batra, M and Chhibber, S and Harjai, K}, title = {Nanolipoidal α-terpineol modulates quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa.}, journal = {Nanomedicine (London, England)}, volume = {15}, number = {18}, pages = {1743-1760}, doi = {10.2217/nnm-2020-0134}, pmid = {32722996}, issn = {1748-6963}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Molecular Docking Simulation ; *Pseudomonas aeruginosa ; *Quorum Sensing ; Virulence ; Virulence Factors/genetics/pharmacology ; }, abstract = {Aim:Pseudomonas aeruginosa has emerged as a major opportunistic pathogen meaning there is an immediate need to develop efficient antivirulence agents which offer a new class of superior therapeutics. Methods: Nanostructured lipid carriers (NLCs) containing α-terpineol (αT) were developed and characterized to determine expression profiles of quorum sensing regulated genes, antivirulence activity and antibiofilm effects against P. aeruginosa. Results: The αT-NLCs had a size of 145.4 nm, polydispersity index of 0.242 and ζ-potential of -31.4 mV. They exhibited pronounced effects on the inhibition of quorum sensing mediated virulence and biofilm formation which were confirmed by molecular docking analysis and gene expression profiles. Conclusion: αT-NLCs show promise as effective antivirulence agents against P. aeruginosa in the postantibiotic era.}, } @article {pmid32722654, year = {2020}, author = {Bossi Esteves, M and Lopes Nalin, J and Kudlawiec, K and Caserta Salviatto, R and de Melo Sales, T and Sicard, A and Piacentini Paes de Almeida, R and Alves de Souza, A and Roberto Spotti Lopes, J}, title = {XadA2 Adhesin Decreases Biofilm Formation and Transmission of Xylella fastidiosa subsp. pauca.}, journal = {Insects}, volume = {11}, number = {8}, pages = {}, pmid = {32722654}, issn = {2075-4450}, abstract = {Xylella fastidiosa is a vector-borne bacterium that causes diseases in many plants of economic interest. The bacterium-vector initial interactions involve bacterial membrane-bound adhesins that mediate cell attachment to the foregut of insect vectors. We investigated the role of the afimbrial adhesin XadA2 in the binding and biofilm formation of X. fastidiosa subsp. pauca to vector surfaces in vitro, as well as its potential to disrupt pathogen transmission. We showed that XadA2 has binding affinity for polysaccharides on sharpshooter hindwings, used as a proxy for the interactions between X. fastidiosa and vectors. When in a medium without carbon sources, the bacterium used wing components, likely chitin, as a source of nutrients and formed a biofilm on the wing surface. There was a significant reduction in X. fastidiosa biofilm formation and cell aggregation on vector wings in competition assays with XadA2 or its specific antibody (anti-XadA2). Finally, pathogen acquisition and transmission to plant were significantly reduced when the vectors acquired X. fastidiosa from an artificial diet supplemented with anti-XadA2. These results show that XadA2 is important in mediating bacterial colonization in the insect and that it could be used as a target for blocking X. fastidiosa transmission.}, } @article {pmid32722296, year = {2020}, author = {Fauzia, KA and Miftahussurur, M and Syam, AF and Waskito, LA and Doohan, D and Rezkitha, YAA and Matsumoto, T and Tuan, VP and Akada, J and Yonezawa, H and Kamiya, S and Yamaoka, Y}, title = {Biofilm Formation and Antibiotic Resistance Phenotype of Helicobacter pylori Clinical Isolates.}, journal = {Toxins}, volume = {12}, number = {8}, pages = {}, pmid = {32722296}, issn = {2072-6651}, support = {221S0002//Ministry of Education, Culture, Sports, Science and Technology/International ; 16H06279//Ministry of Education, Culture, Sports, Science and Technology/International ; 18KK0266//Ministry of Education, Culture, Sports, Science and Technology/International ; 19H03473//Ministry of Education, Culture, Sports, Science and Technology/International ; 18K16182//Ministry of Education, Culture, Sports, Science and Technology/International ; Institutional Program for Young Researcher Overseas Visits and the Strategic Funds for the Promotion of Science and Technology Agency (JST)//Japan Society for the Promotion of Science/International ; no. 123.4/D2.3/KP/2018//World Class Professor Program 2018/International ; 340/UN3.14/LT/2019//Hibah Riset Mandat Universitas Airlangga/International ; }, mesh = {Amoxicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Clarithromycin/pharmacology ; *Drug Resistance, Bacterial ; Dyspepsia/microbiology ; Helicobacter Infections/microbiology ; Helicobacter pylori/*drug effects/isolation & purification/physiology ; Humans ; Indonesia ; Levofloxacin/pharmacology ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; Phenotype ; Tetracycline/pharmacology ; }, abstract = {We evaluated biofilm formation of clinical Helicobacter pylori isolates from Indonesia and its relation to antibiotic resistance. We determined the minimum inhibition concentration (MIC) of amoxicillin, clarithromycin, levofloxacin, metronidazole and tetracycline by the Etest to measure the planktonic susceptibility of 101 H. pylori strains. Biofilms were quantified by the crystal violet method. The minimum biofilm eradication concentration (MBEC) was obtained by measuring the survival of bacteria in a biofilm after exposure to antibiotics. The majority of the strains formed a biofilm (93.1% (94/101)), including weak (75.5%) and strong (24.5%) biofilm-formers. Planktonic resistant and sensitive strains produced relatively equal amounts of biofilms. The resistance proportion, shown by the MBEC measurement, was higher in the strong biofilm group for all antibiotics compared to the weak biofilm group, especially for clarithromycin (p = 0.002). Several cases showed sensitivity by the MIC measurement, but resistance according to the MBEC measurements (amoxicillin, 47.6%; tetracycline, 57.1%; clarithromycin, 19.0%; levofloxacin, 38.1%; and metronidazole 38.1%). Thus, biofilm formation may increase the survival of H. pylori and its resistance to antibiotics. Biofilm-related antibiotic resistance should be evaluated with antibiotic susceptibility.}, } @article {pmid32721752, year = {2020}, author = {Song, Z and Zhang, X and Sun, F and Ngo, HH and Guo, W and Wen, H and Li, C and Zhang, Z}, title = {Specific microbial diversity and functional gene (AOB amoA) analysis of a sponge-based aerobic nitrifying moving bed biofilm reactor exposed to typical pharmaceuticals.}, journal = {The Science of the total environment}, volume = {742}, number = {}, pages = {140660}, doi = {10.1016/j.scitotenv.2020.140660}, pmid = {32721752}, issn = {1879-1026}, mesh = {Ammonia ; Bacteria ; *Biofilms ; *Bioreactors ; Nitrification ; Wastewater ; }, abstract = {Four bench-scale sponge-based aerobic nitrifying moving bed biofilm reactors (MBBRs) were used to treat municipal wastewater containing typical pharmaceuticals (1 mg/L, 2 mg/L and 5 mg/L). This preliminary research aims to investigate the effects of sulfadiazine (SDZ), ibuprofen (IBU) and carbamazepine (CBZ) on nitrification performance and explore specific microbial diversity and functional gene (Ammonia-oxidizing bacteria (AOB), amoA) of MBBRs. After 90 days of operation, the MBBR without pharmaceuticals could remove up to 97.4 ± 1.5% of NH4[+]-N while the removals of NH4[+]-N by the MBBRs with SDZ, IBU and CBZ were all suppressed to varying degrees. Based on the Shannon and Chao 1 index, the specific microbial diversity and richness in biofilm samples increased at a range of 1 mg/L to 2 mg/L pharmaceuticals (SDZ, IBU or CBZ) and started decreasing after the pharmaceutical concentration was higher than 2 mg/L. The determination of functional gene (AOB amoA) showed that Proteobacteria was the most dominant bacteria within all biofilms with the relative abundance ranging from 24.81% to 55.32%. Furthermore, Nitrosomonas was the most numerous genus in AOB, followed by Campylobacter and Thauera, whose relative abundance shifted under the pressure of different pharmaceuticals.}, } @article {pmid32719941, year = {2020}, author = {Lee, YJ and Wang, C}, title = {Proteomic analysis reveals the temperature-dependent presence of extracytoplasmic peptidases in the biofilm exoproteome of Listeria monocytogenes EGD-e.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {58}, number = {9}, pages = {761-771}, doi = {10.1007/s12275-020-9522-8}, pmid = {32719941}, issn = {1976-3794}, mesh = {Biofilms/*growth & development ; Cell Membrane/enzymology ; Cell Wall/*enzymology ; Chromatography, Liquid ; Listeria monocytogenes/*metabolism ; Peptide Hydrolases/*analysis/*metabolism ; Protease Inhibitors/pharmacology ; Proteome/analysis ; Tandem Mass Spectrometry ; }, abstract = {The foodborne pathogen Listeria monocytogenes resists environmental stresses by forming biofilms. Because this pathogen transmits between the environment and the host, it must adapt to temperature as an environmental stress. In this study, we aimed to identify which proteins were present depending on the temperature in the biofilms of L. monocytogenes EGD-e. Proteins in the supernatants of biofilms formed at 25°C and 37°C were compared using two-dimensional gel electrophoresis and liquid chromatography with tandem mass spectrometry. The larger number of extracytoplasmic proteins associated with cell wall/membrane/envelop biogenesis was identified from the supernatant of biofilms formed at 25°C (7) than those at 37°C (0). Among the 16 extracytoplasmic proteins detected only at 25°C, three were peptidases, namely Spl, Cwh, and Lmo0186. Moreover, mRNA expression of the three peptidases was higher at 25°C than at 37°C. Interestingly, this adaptation of gene expression to temperature was present in sessile cells but not in dispersed cells. After inhibiting the activity of extracytoplasmic peptidases with a protease inhibitor, we noted that the levels of biofilm biomass increased with higher concentrations of the protease inhibitor only when L. monocytogenes grew biofilms at 25°C and not at 37°C. Overall, our data suggest an effect of temperature on the presence of peptidases in L. monocytogenes biofilms. Additionally, increasing the levels of extracytoplasmic peptidases in biofilms is likely a unique feature for sessile L. monocytogenes that causes a naturally occurring breakdown of biofilms and facilitates the pathogen exiting biofilms and disseminating into the environment.}, } @article {pmid32715767, year = {2020}, author = {Romeu, MJL and Domínguez-Pérez, D and Almeida, D and Morais, J and Campos, A and Vasconcelos, V and Mergulhão, FJM}, title = {Characterization of planktonic and biofilm cells from two filamentous cyanobacteria using a shotgun proteomic approach.}, journal = {Biofouling}, volume = {36}, number = {6}, pages = {631-645}, doi = {10.1080/08927014.2020.1795141}, pmid = {32715767}, issn = {1029-2454}, mesh = {*Biofilms ; Chromatography, Liquid ; *Cyanobacteria ; *Plankton ; *Proteomics ; Tandem Mass Spectrometry ; }, abstract = {Cyanobacteria promote marine biofouling with significant impacts. A qualitative proteomic analysis, by LC-MS/MS, of planktonic and biofilm cells from two cyanobacteria was performed. Biofilms were formed on glass and perspex at two relevant hydrodynamic conditions for marine environments (average shear rates of 4 s[-1] and 40 s[-1]). For both strains and surfaces, biofilm development was higher at 4 s[-1]. Biofilm development of Nodosilinea sp. LEGE 06145 was substantially higher than Nodosilinea sp. LEGE 06119, but no significant differences were found between surfaces. Overall, 377 and 301 different proteins were identified for Nodosilinea sp. LEGE 06145 and Nodosilinea sp. LEGE 06119. Differences in protein composition were more noticeable in biofilms formed under different hydrodynamic conditions than in those formed on different surfaces. Ribosomal and photosynthetic proteins were identified in most conditions. The characterization performed gives new insights into how shear rate and surface affect the planktonic to biofilm transition, from a structural and proteomics perspective.}, } @article {pmid32714744, year = {2020}, author = {Pu, J and Liu, Y and Zhang, J and An, B and Li, Y and Wang, X and Din, K and Qin, C and Li, K and Cui, M and Liu, S and Huang, Y and Wang, Y and Lv, Y and Huang, J and Cui, Z and Zhao, S and Zhong, C}, title = {Virus Disinfection from Environmental Water Sources Using Living Engineered Biofilm Materials.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {7}, number = {14}, pages = {1903558}, pmid = {32714744}, issn = {2198-3844}, abstract = {Waterborne viruses frequently cause disease outbreaks and existing strategies to remove such viral pathogens often involve harsh or energy-consuming water treatment processes. Here, a simple, efficient, and environmentally friendly approach is reported to achieve highly selective disinfection of specific viruses with living engineered biofilm materials. As a proof-of-concept, Escherichia coli biofilm matrix protein CsgA was initially genetically fused with the influenza-virus-binding peptide (C5). The resultant engineered living biofilms could correspondingly capture virus particles directly from aqueous solutions, disinfecting samples to a level below the limit-of-detection for a qPCR-based detection assay. By exploiting the surface-adherence properties of biofilms, it is further shown that polypropylene filler materials colonized by the CsgA-C5 biofilms can be utilized to disinfect river water samples with influenza titers as high as 1 × 10[7] PFU L[-1]. Additionally, a suicide gene circuit is designed and applied in the engineered strain that strictly limits the growth of bacterial, therefore providing a viable route to reduce potential risks confronted with the use of genetically modified organisms. The study thus illustrates that engineered biofilms can be harvested for the disinfection of pathogens from environmental water samples in a controlled manner and highlights the unique biology-only properties of living substances for material applications.}, } @article {pmid32714301, year = {2020}, author = {Bidossi, A and Bottagisio, M and Savadori, P and De Vecchi, E}, title = {Identification and Characterization of Planktonic Biofilm-Like Aggregates in Infected Synovial Fluids From Joint Infections.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1368}, pmid = {32714301}, issn = {1664-302X}, abstract = {Recent in vitro studies reported the exceptional ability of some bacterial species to form biofilm-like aggregates in human and animal synovial fluids (SF), but evidences from infected clinical samples are still lacking. In this study, we investigated whether this bacterial phenotype was present in infected SFs collected from joint infections and if it was maintained in in vitro settings. SFs sent for culture to the Laboratory of Microbiology of our institute were directly analyzed by means of confocal laser scanning microscopy (CLSM), and the infective agents were isolated for further in vitro tests. Moreover, sterile SF was collected from patients who did not receive previous antibiotic therapy to investigate the formation of bacterial aggregates, together with biofilm and matrix production on a titanium surface. Finally, antibiotic susceptibility studies were performed by using bovine SF. Four Staphylococcus aureus, one Staphylococcus lugdunensis, and one Prevotella bivia strain were identified in the infected SFs. The CLSM analysis showed that all staphylococci were present as a mixture of single cells and bacterial clumps surrounded by an exopolymeric substance, which comprised SF-derived fibrin, while all P. bivia cells appeared separated. Despite that, differences in the ability to aggregate between S. aureus and S. lugdunensis were observed in clinical SFs. These different phenotypes were further confirmed by in vitro growth, even though the application of such ex vivo approach lead all staphylococci to form exceptionally large microbial aggregates, which are several folds bigger than those observed in clinical samples. Planktonic aggregates challenged for antibiotic susceptibility revealed a sharp increase of recalcitrance to the treatments. Although this is still at a preliminary stage, the present work confirmed the ability of staphylococci to form free-floating biofilm-like aggregates in infected SF from patients with joint infections. Furthermore, the obtained results pointed out that future in vitro research on joint infections will benefit from the use of human- or animal-derived SF. Even though this approach should be carefully validated in further studies comprising a larger microbial population, these findings pose new challenges in the treatment of infected native and prosthetic joints and for the approach to new investigations.}, } @article {pmid32712662, year = {2021}, author = {Song, YD and Hsu, CC and Lew, SQ and Lin, CH}, title = {Candida tropicalis RON1 is required for hyphal formation, biofilm development, and virulence but is dispensable for N-acetylglucosamine catabolism.}, journal = {Medical mycology}, volume = {59}, number = {4}, pages = {379-391}, doi = {10.1093/mmy/myaa063}, pmid = {32712662}, issn = {1460-2709}, mesh = {Acetylglucosamine/*metabolism ; Biofilms/*growth & development ; Candida tropicalis/*genetics/*growth & development/pathogenicity/physiology ; Gene Expression Regulation, Fungal ; Hyphae/*growth & development ; Receptor Protein-Tyrosine Kinases/*genetics ; Virulence/genetics ; }, abstract = {UNLABELLED: NDT80-like family genes are highly conserved across a large group of fungi, but the functions of each Ndt80 protein are diverse and have evolved differently among yeasts and pathogens. The unique NDT80 gene in budding yeast is required for sexual reproduction, whereas three NDT80-like genes, namely, NDT80, REP1, and RON1, found in Candida albicans exhibit distinct functions. Notably, it was suggested that REP1, rather than RON1, is required for N-acetylglucosamine (GlcNAc) catabolism. Although Candida tropicalis, a widely dispersed fungal pathogen in tropical and subtropical areas, is closely related to Candida albicans, its phenotypic, pathogenic and environmental adaptation characteristics are remarkably divergent. In this study, we focused on the Ron1 transcription factor in C. tropicalis. Protein alignment showed that C. tropicalis Ron1 (CtRon1) shares 39.7% identity with C. albicans Ron1 (CaRon1). Compared to the wild-type strain, the C. tropicalis ron1Δ strains exhibited normal growth in different carbon sources and had similar expression levels of several GlcNAc catabolic genes during GlcNAc treatment. In contrast, C. tropicalis REP1 is responsible for GlcNAc catabolism and is involved in GlcNAc catabolic gene expressions, similar to C. albicans Rep1. However, REP1 deletion strains in C. tropicalis promote hyphal development in GlcNAc with low glucose content. Interestingly, CtRON1, but not CaRON1, deletion mutants exhibited significantly impaired hyphal growth and biofilm formation. As expected, CtRON1 was required for full virulence. Together, the results of this study showed divergent functions of CtRon1 compared to CaRon1; CtRon1 plays a key role in yeast-hyphal dimorphism, biofilm formation and virulence.

LAY ABSTRACT: In this study, we identified the role of RON1, an NDT80-like gene, in Candida tropicalis. Unlike the gene in Candida albicans, our studies showed that RON1 is a key regulator of hyphal formation, biofilm development and virulence but is dispensable for N-acetylglucosamine catabolism in C. tropicalis.}, } @article {pmid32712501, year = {2020}, author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA}, title = {Controlling biofilm retention time in an A-stage high-rate moving bed biofilm reactor for organic carbon redirection.}, journal = {The Science of the total environment}, volume = {745}, number = {}, pages = {141051}, doi = {10.1016/j.scitotenv.2020.141051}, pmid = {32712501}, issn = {1879-1026}, mesh = {Biofilms ; Biomass ; Bioreactors ; *Carbon ; *Waste Disposal, Fluid ; }, abstract = {The A-stage of the AB process can minimize carbon oxidation by redirecting carbon to side-stream processes for harvesting carbon as energy and/or bioproduct. The redirection/harvesting of carbon has been studied in systems which utilize suspended biomass cultures. The potential of high-rate moving bed biofilm reactors, however, has not been explored. This study sought to control the biofilm solids retention time in a high-rate moving bed biofilm reactor operated at 17 ± 4 g-bCOD m[-2]d[-1]. Biofilm solids retention time was controlled by one of two strategies (i.e., 100% and 60% effective biofilm removal) that targeted several nominal biofilm solids retention times (i.e., 8, 6, 4, and 2 days) by employing different biocarrier replacement times. The results demonstrated that the suspended solids activity could be reduced by decreasing the nominal biofilm solids retention time. Using the 60% biofilm removal strategy, the actual biofilm solids retention time with a nominal biofilm solids retention time of 2 days was 12 h. When utilizing the 100% biofilm removal strategy, an actual biofilm solids retention time of less than 3 h was achieved with a nominal biofilm solids retention time of 2 days. The control reactor, which was a conventional moving bed biofilm reactor with no biocarrier replacement, was estimated to have a biofilm solids retention time of 2 days. Overall, the biofilm removal strategies favored carbon redirection and maximized the biomass yield at 1.1 ± 0.3 g-TSS g-COD[-1] removed.}, } @article {pmid32712354, year = {2021}, author = {Kim, HS and Jang, Y and Ham, SY and Park, JH and Kang, HJ and Yun, ET and Shin, DH and Kim, KC and Park, HD}, title = {Effect of broad-spectrum biofilm inhibitor raffinose, a plant galactoside, on the inhibition of co-culture biofilm on the microfiltration membrane.}, journal = {Journal of hazardous materials}, volume = {402}, number = {}, pages = {123501}, doi = {10.1016/j.jhazmat.2020.123501}, pmid = {32712354}, issn = {1873-3336}, mesh = {Biofilms ; *Biofouling/prevention & control ; Bioreactors ; Coculture Techniques ; Galactosides ; Membranes, Artificial ; Raffinose ; Sewage ; *Staphylococcus aureus ; }, abstract = {A membrane bioreactor (MBR) integrates process such as membrane filtration and biological treatment of activated sludge. However, organic, inorganic and biological matters cause membrane fouling, which seriously affects membrane performance. The goal of this study was to evaluate the biofouling inhibition capacity of raffinose during the MBR process. The results showed that 0-1,000 μM raffinose significantly reduced the formation of the P. aeruginosa and S. aureus co-culture biofilm by about 25-52 % in a concentration-dependent manner. In addition, the effect of raffinose on the microfiltration membrane biofilm was tested in a flow reactor and lab-scale MBR unit. The results showed that the co-culture biofilm and transmembrane pressure were decreased by raffinose treatment compared to those by furanone C-30 treatment. These results clearly demonstrated that raffinose, broad-spectrum biofilm inhibitor, inhibits biofilm formation in mixed cultures and could be used to mitigate biofouling in MBR processes.}, } @article {pmid32711113, year = {2020}, author = {Mirzaei, R and Mohammadzadeh, R and Sholeh, M and Karampoor, S and Abdi, M and Dogan, E and Moghadam, MS and Kazemi, S and Jalalifar, S and Dalir, A and Yousefimashouf, R and Mirzaei, E and Khodavirdipour, A and Alikhani, MY}, title = {The importance of intracellular bacterial biofilm in infectious diseases.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104393}, doi = {10.1016/j.micpath.2020.104393}, pmid = {32711113}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms ; *Communicable Diseases ; *Haemophilus Infections ; Haemophilus influenzae ; Humans ; Moraxella catarrhalis ; }, abstract = {Various bacterial species, previously known as extracellular pathogens, can reside inside different host cells by adapting to intracellular modes by forming microbial aggregates with similar characteristics to bacterial biofilms. Additionally, bacterial invasion of human cells leads to failure in antibiotic therapy, as most conventional anti-bacterial agents cannot reach intracellular biofilm in normal concentrations. Various studies have shown that bacteria such as uropathogenic Escherichia coli, Pseudomonas aeruginosa, Borrelia burgdorferi,Moraxella catarrhalis, non-typeable Haemophilus influenzae, Streptococcus pneumonia, and group A Streptococci produce biofilm-like structures within the host cells. For the first time in this review, we will describe and discuss the new information about intracellular bacterial biofilm formation and its importance in bacterial infectious diseases.}, } @article {pmid32711085, year = {2020}, author = {Mekky, AEM and Sanad, SMH}, title = {Novel bis(pyrazole-benzofuran) hybrids possessing piperazine linker: Synthesis of potent bacterial biofilm and MurB inhibitors.}, journal = {Bioorganic chemistry}, volume = {102}, number = {}, pages = {104094}, doi = {10.1016/j.bioorg.2020.104094}, pmid = {32711085}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antineoplastic Agents/chemical synthesis/chemistry/*pharmacology ; Benzofurans/chemistry/pharmacology ; Biofilms/*drug effects ; Carbohydrate Dehydrogenases/*antagonists & inhibitors/metabolism ; Cell Line ; Cell Proliferation/drug effects ; Dose-Response Relationship, Drug ; Drug Resistance, Bacterial/drug effects ; Drug Screening Assays, Antitumor ; Enterococcus faecalis/drug effects ; Escherichia coli/drug effects ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Piperazine/chemistry/pharmacology ; Pyrazoles/chemistry/pharmacology ; Staphylococcus aureus/drug effects ; Structure-Activity Relationship ; }, abstract = {Novel 1,4-bis[(2-(3-(dimethylamino)-1-oxoprop-2-en-1-yl)benzofuran-5-yl)methyl]piperazine was prepared and used as a key synthon for the this study. Therefore, 1,3-dipolar cycloaddition of this synthon with the appropriate hydrazonyl chlorides afforded a new series of bis(1,3,4-trisubstituted pyrazoles), linked via piperazine moiety. Furthermore, it reacted with hydrazine hydrate and phenyl hydrazine individually to afford the corresponding 1,4-bis[(2-(1H-pyrazolyl)benzofuran-5-yl)methyl]piperazines. Different bacterial strains and cell lines were selected to study the in-vitro antibacterial and cytotoxic activities for the new derivatives. 1,4-Bis[((2-(3-acetyl-1-(4-nitrophenyl)-1H-pyrazole-4-yl)carbonyl)benzofuran-5-yl)methyl]piperazine 5e showed the best antibacterial efficacies with MIC/MBC values of 1.2/1.2, 1.2/2.4 and 1.2/2.4 μM against each of E. coli, S. aureus and S. mutans strains, respectively. In addition, the inhibitory activity of some new bis(pyrazoles) as MRSA and VRE inhibitors were studied. Compound 5e gave the best inhibitory activity with MIC/MBC values of 18.1/36.2, 9.0/18.1 and 18.1/18.1 µM, respectively, against MRSA (ATCC:33591 and ATCC:43300) and VRE (ATCC:51575) bacterial strains, respectively. Compound 5e showed more effective biofilm inhibition activities than the reference Ciprofloxacin. It showed IC50 values of 3.0 ± 0.05, 3.2 ± 0.08 and 3.3 ± 0.07 μM against S. aureus, S. mutans and E. coli strains, respectively. Furthermore, experimental study showed excellent inhibitory activities of 1,4-bis[((2-(3-substituted-1-aryl-1H-pyrazole-4-yl)carbonyl)benzofuran-5-yl)methyl]piperazine derivatives, attached to p-NO2 or p-Cl groups, against MurB enzyme. Compound 5e gave the best MurB inhibitory activity with IC50 value of 3.1 μM. The in-silico study was performed to predict the capability of new derivatives as potential inhibitors of MurB enzyme.}, } @article {pmid32710776, year = {2020}, author = {Nelson, J and El-Gendy, AO and Mansy, MS and Ramadan, MA and Aziz, RK}, title = {The biosurfactants iturin, lichenysin and surfactin, from vaginally isolated lactobacilli, prevent biofilm formation by pathogenic Candida.}, journal = {FEMS microbiology letters}, volume = {367}, number = {15}, pages = {}, doi = {10.1093/femsle/fnaa126}, pmid = {32710776}, issn = {1574-6968}, mesh = {Biofilms/*drug effects ; Candida/*drug effects ; Lactobacillus/chemistry ; Lipopeptides/pharmacology ; Lipoproteins/pharmacology ; Peptides, Cyclic/pharmacology ; Surface-Active Agents/*pharmacology ; }, abstract = {Lactic acid bacteria (LAB), particularly lactobacilli, are major components of the vaginal microbiota. Lactobacilli are facultative anaerobes forming a critical line of defense against pathogenic microorganisms, including those forming biofilms, such as Candida spp. This study aimed to investigate the anti-adhesion capabilities of vaginal Lactobacillus isolates against biofilms formed by pathogenic Candida species. When the extracellular biosurfactant activities of culture supernatants from 120 Lactobacillus isolates were evaluated by the oil-spreading method, clear spreading zones were recognized. Biofilm formation was quantified by the crystal violet plate assay, and different isolates exhibited anti-adhesion activity that ranged from 65.6to 74.4% inhibition against Candida spp. biofilms. Liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HRESIMS) identified biosurfactants, extracted from three representative Lactobacillus isolates, as surfactin, iturin and lichenysin. Finally, the distribution of representative genes from six different biosynthetic clusters, related to the production of different biosurfactants, was investigated by the polymerase chain reaction. In conclusion, surfactin, iturin and lichenysin were identified for the first time in vaginal Lactobacillus spp. These biosurfactants, which showed strong anti-adherence activity may be used as promising antibiofilm agents in equipment care to prevent vaginal infections by pathogenic Candida spp. with the prospect of reducing nosocomial infections.}, } @article {pmid32709907, year = {2020}, author = {Ahmed, MN and Abdelsamad, A and Wassermann, T and Porse, A and Becker, J and Sommer, MOA and Høiby, N and Ciofu, O}, title = {The evolutionary trajectories of P. aeruginosa in biofilm and planktonic growth modes exposed to ciprofloxacin: beyond selection of antibiotic resistance.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {28}, pmid = {32709907}, issn = {2055-5008}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Cytoskeletal Proteins/genetics ; *Drug Resistance, Bacterial ; Evolution, Molecular ; Flavoproteins/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Genetic Fitness ; Genotype ; Mutation ; Plankton/*drug effects ; Pseudomonas aeruginosa/drug effects/*physiology ; Quorum Sensing ; }, abstract = {Ciprofloxacin (CIP) is used to treat Pseudomonas aeruginosa biofilm infections. We showed that the pathways of CIP-resistance development during exposure of biofilms and planktonic P. aeruginosa populations to subinhibitory levels of CIP depend on the mode of growth. In the present study, we analyzed CIP-resistant isolates obtained from previous evolution experiments, and we report a variety of evolved phenotypic and genotypic changes that occurred in parallel with the evolution of CIP-resistance. Cross-resistance to beta-lactam antibiotics was associated with mutations in genes involved in cell-wall recycling (ftsZ, murG); and could also be explained by mutations in the TCA cycle (sdhA) genes and in genes involved in arginine catabolism. We found that CIP-exposed isolates that lacked mutations in quorum-sensing genes and acquired mutations in type IV pili genes maintained swarming motility and lost twitching motility, respectively. Evolved CIP-resistant isolates showed high fitness cost in planktonic competition experiments, yet persisted in the biofilm under control conditions, compared with ancestor isolates and had an advantage when exposed to CIP. Their persistence in biofilm competition experiments in spite of their fitness cost in planktonic growth could be explained by their prolonged lag-phase. Interestingly, the set of mutated genes that we identified in these in vitro-evolved CIP-resistant colonies, overlap with a large number of patho-adaptive genes previously reported in P. aeruginosa isolates from cystic fibrosis (CF) patients. This suggests that the antibiotic stress is contributing to the bacterial evolution in vivo, and that adaptive laboratory evolution can be used to predict the in vivo evolutionary trajectories.}, } @article {pmid32709126, year = {2020}, author = {Adame-Gómez, R and Cruz-Facundo, IM and García-Díaz, LL and Ramírez-Sandoval, Y and Pérez-Valdespino, A and Ortuño-Pineda, C and Santiago-Dionisio, MC and Ramírez-Peralta, A}, title = {Biofilm Production by Enterotoxigenic Strains of Bacillus cereus in Different Materials and under Different Environmental Conditions.}, journal = {Microorganisms}, volume = {8}, number = {7}, pages = {}, pmid = {32709126}, issn = {2076-2607}, support = {PFCE 2019//Secretaria de Educación Pública/International ; }, abstract = {Foodborne illnesses, such as infections or food poisoning, can be caused by bacterial biofilms present in food matrices or machinery. The production of biofilms by several strains of Bacillus cereus on different materials under different culture conditions was determined, as well as the relationship of biofilms with motility, in addition to the enterotoxigenic profile and candidate genes that participate in the production of biofilms. Biofilm production of B. cereus strains was determined on five materials: glass, polystyrene, polyethylene, polyvinylchloride (PVC), PVC/glass; in three culture media: Phenol red broth, tryptic soy broth, and brain heart infusion broth; in two different temperatures (37 °C and 25 °C), and in two different oxygen conditions (oxygen and CO2 tension). Furthermore, the strains were molecularly characterized by end-point polymerase chain reaction. Motility was determined on semi-solid agar. The B. cereus strains in this study were mainly characterized as enterotoxigenic strains; statistically significant differences were found in the PVC material and biofilm production. Motility was positively associated with the production of biofilm in glass/PVC. The sipW and tasA genes were found in two strains. The results of this study are important in the food industry because the strains carry at least one enterotoxin gene and produce biofilms on different materials.}, } @article {pmid32708754, year = {2020}, author = {Andrade, JC and João, AL and Alonso, CS and Barreto, AS and Henriques, AR}, title = {Genetic Subtyping, Biofilm-Forming Ability and Biocide Susceptibility of Listeria monocytogenes Strains Isolated from a Ready-to-Eat Food Industry.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, pmid = {32708754}, issn = {2079-6382}, support = {Project UID/CVT/00276/2019//CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon/ ; }, abstract = {Listeria monocytogenes is a foodborne pathogen of special concern for ready-to-eat food producers. The control of its presence is a critical step in which food-grade sanitizers play an essential role. L. monocytogenes is believed to persist in food processing environments in biofilms, exhibiting less susceptibility to sanitizers than planktonic cells. This study aimed to test the susceptibility of L. monocytogenes in planktonic culture and biofilm to three commercial food-grade sanitizers and to benzalkonium chloride; together with the genetic subtyping of the isolates. L. monocytogenes isolates were collected from raw materials, final products and food-contact surfaces during a 6-year period from a ready-to-eat meat-producing food industry and genetically characterized. Serogrouping and pulsed-field gel electrophoresis (PFGE) revealed genetic variability and differentiated L. monocytogenes isolates in three clusters. The biofilm-forming ability assay revealed that the isolates were weak biofilm producers. L. monocytogenes strains were susceptible both in the planktonic and biofilm form to oxidizing and ethanol-based compounds and to benzalkonium chloride, but not to quaternary ammonium compound. A positive association of biofilm-forming ability and LD90 values for quaternary ammonium compound and benzalkonium chloride was found. This study highlights the need for preventive measures improvement and for a conscious selection and use of sanitizers in food-related environments to control Listeria monocytogenes.}, } @article {pmid32708039, year = {2020}, author = {Kunicka-Styczyńska, A and Tyfa, A and Laskowski, D and Plucińska, A and Rajkowska, K and Kowal, K}, title = {Clove Oil (Syzygium aromaticum L.) Activity against Alicyclobacillus acidoterrestris Biofilm on Technical Surfaces.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {15}, pages = {}, pmid = {32708039}, issn = {1420-3049}, mesh = {Alicyclobacillus/*drug effects ; Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Clove Oil/*chemistry/pharmacology ; Glass/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*chemistry/pharmacology ; Polyvinyl Chloride/chemistry ; Surface Properties ; Syzygium/*chemistry ; }, abstract = {Acidotermophilic bacteria Alicyclobacillus acidoterrestris is one of the main contaminants in the fruit industry forming biofilms which are difficult to remove from the production line by conventional methods. An alternative approach aims for the use of essential oils to prevent Alicyclobacillus biofilm development. The effect of clove essential oil on A. acidoterrestris biofilms on glass and polyvinyl chloride surfaces under static and agitated culture conditions was investigated by atomic force microscopy and the plate count method. The medium-flow and the type of technical surface significantly influenced A. acidoterrestris biofilm. The PVC was colonized in a greater extent comparing to glass. Clove essential oil in 0.05% (v/v) caused 25.1-65.0% reduction of biofilms on the technical surfaces along with substantial changes in their morphology by a decrease in the biofilm: height, surface roughness, and surface area difference. The oil also induced alteration in individual bacterial cells length and visible increase of their roughness. Clove essential oil seems to release EPS from biofilm and thus induce detachment of bacteria from the surface. Due to anti-A. acidoterrestris biofilm activity, the clove oil may be used in the juice industry to hinder a development of A. acidoterrestris biofilms on production surfaces.}, } @article {pmid32707856, year = {2020}, author = {de Figueiredo, KA and da Silva, HDP and Miranda, SLF and Gonçalves, FJDS and de Sousa, AP and de Figueiredo, LC and Feres, M and Bueno-Silva, B}, title = {Brazilian Red Propolis Is as Effective as Amoxicillin in Controlling Red-Complex of Multispecies Subgingival Mature Biofilm In Vitro.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {32707856}, issn = {2079-6382}, support = {PROEX program (grant number 0475/2019, process number 23038.005614/2019-74)//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {This study investigated the effects of Brazilian Red Propolis (BRP) extract on seven-day-old multispecies subgingival biofilms. Mixed biofilm cultures containing 31 species associated with periodontal health or disease were grown for six days on a Calgary device. Then, mature biofilms were treated for 24 h with BRP extract at different concentrations (200-1600 µg/mL), amoxicillin (AMOXI) at 54 µg/mL (positive control) or vehicle (negative control). Biofilm metabolic activity was determined by colorimetry, and bacterial counts/proportions were determined by DNA-DNA hybridization. Data were analyzed by Kruskal-Wallis and Dunn's tests. Treatment with BRP at 1600, 800 and 400 μg/mL reduced biofilm metabolic activity by 56%, 56% and 57%, respectively, as compared to 65% reduction obtained with AMOXI. Mean total cell counts were significantly reduced in all test groups (~50-55%). Lower proportions of red, green and yellow complex species were observed upon treatment with BRP (400 µg/mL) and AMOXI, but only AMOXI reduced the proportions of Actinomyces species. In conclusion, BRP extract was as effective as AMOXI in killing seven-day-old multispecies biofilm pathogens and did not affect the levels of the host-compatible Actinomyces species. These data suggest that BRP may be an alternative to AMOXI as an adjunct in periodontal therapy. In vivo studies are needed to validate these results.}, } @article {pmid32707220, year = {2020}, author = {Marinković, J and Ćulafić, DM and Nikolić, B and Đukanović, S and Marković, T and Tasić, G and Ćirić, A and Marković, D}, title = {Antimicrobial potential of irrigants based on essential oils of Cymbopogon martinii and Thymus zygis towards in vitro multispecies biofilm cultured in ex vivo root canals.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104842}, doi = {10.1016/j.archoralbio.2020.104842}, pmid = {32707220}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Child ; Cymbopogon/*chemistry ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; *Oils, Volatile/pharmacology ; Root Canal Irrigants/*pharmacology ; Sodium Hypochlorite ; Thymus Plant/*chemistry ; }, abstract = {OBJECTIVE: The objective was to determine the antibiofilm efficacy of Cymbopogon martinii and Thymus zygis essential oils and to estimate the disruption potential of oil-based endodontic irrigants on the multispecies biofilm formed in the root canals of extracted teeth.

DESIGN: The essential oils were characterized (GC-MS), while their antibacterial and cytotoxic properties were detected by microdilution and MTT assays. Particles sizes and polydispersity indices were determined for the irrigants. The isolates from root canals of pediatric patients were identified (MALDI-TOF). The multispecies biofilms were formed from Streptococcus mitis, Streptococcus sanguinis and Enterococcus faecalis. Antibiofilm properties of the essential oils and irrigants were determined by crystal violet and plate counting assay. Statistical analysis was performed by one-way ANOVA.

RESULTS: The screening of biofilm biomass revealed a disruption potential of C. martinii essential oil. The plate counting assay showed the efficacy of both oils in diminishing cell viability: high in biofilms (reduction of log10CFU was 2.75-2.87) and moderate in the planktons formed above. The essential oil-based irrigants showed the same antibiofilm activity as in the control (1.5 % sodium hypochlorite) for C. martini and almost 2-fold higher for T. zygis. Successive irrigations with 1.5 % sodium hypochlorite, saline and an oil-based irrigant was more efficient for C. martini than for the control (reductions of log10CFU was 1.69 and 1.14, respectively).

CONCLUSIONS: Notable activities achieved by essential oils and oil-based irrigants, particularly regarding C. martini, against the biofilm consisting of S. mitis, S. sanguinis, and E. faecalis, are expected to encourage further research in endodontics.}, } @article {pmid32702578, year = {2020}, author = {Zhang, Q and Chen, X and Zhang, Z and Luo, W and Wu, H and Zhang, L and Zhang, X and Zhao, T}, title = {Performance and microbial ecology of a novel moving bed biofilm reactor process inoculated with heterotrophic nitrification-aerobic denitrification bacteria for high ammonia nitrogen wastewater treatment.}, journal = {Bioresource technology}, volume = {315}, number = {}, pages = {123813}, doi = {10.1016/j.biortech.2020.123813}, pmid = {32702578}, issn = {1873-2976}, mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; *Nitrification ; Nitrogen/analysis ; *Wastewater ; }, abstract = {To overcome long start-up time, poor ammonia tolerance and removal performance of traditional moving bed biofilm reactor (MBBR) inoculated with activated sludge for high-ammonia wastewater treatment, a novel MBBR based on heterotrophic nitrification-aerobic denitrification (HN-AD) was proposed. Start-up of MBBR was firstly performed via inoculated with HN-AD bacteria. Start-up time was shortened from 39 d to 15 d, NH4[+] tolerance was enhanced from 200 mg/L to 1000 mg/L, and TN removal was increased from 30.4% to 80.7%. The carrier types and NH4[+] concentration had significant effects on nitrogen removal and microbial ecology. When the NH4[+] concentration was increased to 900 mg/L in MBBR using polyvinyl alcohol gel as carrier, the TN removal, the abundance of HN-AD bacteria Acinetobacter, Pseudomonas and Paracoccus, which played a key role in TN removal and ammonia tolerance, and the abundance of genes related to nitrogen removal were much higher than those of MBBR using kaldness.}, } @article {pmid32701973, year = {2020}, author = {Barros, CHN and Fulaz, S and Vitale, S and Casey, E and Quinn, L}, title = {Interactions between functionalised silica nanoparticles and Pseudomonas fluorescens biofilm matrix: A focus on the protein corona.}, journal = {PloS one}, volume = {15}, number = {7}, pages = {e0236441}, pmid = {32701973}, issn = {1932-6203}, mesh = {Biofilms/*drug effects/growth & development ; Chromatography, Liquid ; Humans ; Metal Nanoparticles/*chemistry ; Protein Corona/chemistry ; Protein Interaction Maps/drug effects ; Pseudomonas fluorescens/*drug effects/growth & development ; Silicon Dioxide/chemistry/*pharmacology ; Tandem Mass Spectrometry ; }, abstract = {Biofilms are microbial communities embedded in an extracellular polymeric matrix and display an enhanced tolerance to the action of antimicrobials. The emergence of novel functionalised nanoparticles is considered a promising avenue for the development of biofilm-specific antimicrobial technologies. However, there is a gap in the understanding of interactions between nanoparticles and the biofilm matrix. Particularly, questions are raised on how nanoparticle charge and surface groups play a role in aggregation when in contact with biofilm components. Herein we present the synthesis of four types of silica nanoparticles and undertake an analysis of their interactions with Pseudomonas fluorescens biofilm matrix. The effect of the biofilm matrix components on the charge and aggregation of the nanoparticles was assessed. Additionally, the study focused on the role of matrix proteins, with the in-depth characterisation of the protein corona of each nanoparticle by Liquid Chromatography with Tandem Mass Spectrometry experiments. The protein corona composition is dependent on the nanoparticle type; non-functionalised nanoparticles show less protein selectivity, whereas carboxylate-functionalised nanoparticles prefer proteins with a higher isoelectric point. These outcomes provide insights into the field of biofilm-nanoparticle interactions that can be valuable for the design of new nano-based targeting systems in future anti-biofilm applications.}, } @article {pmid32700606, year = {2020}, author = {Shi, J and Ma, Z and Pan, H and Liu, Y and Chu, Y and Wang, J and Chen, L}, title = {Biofilm-encapsulated nano drug delivery system for the treatment of colon cancer.}, journal = {Journal of microencapsulation}, volume = {37}, number = {7}, pages = {481-491}, doi = {10.1080/02652048.2020.1797914}, pmid = {32700606}, issn = {1464-5246}, mesh = {Animals ; Antimetabolites, Antineoplastic/*administration & dosage/therapeutic use ; Bacterial Outer Membrane/*chemistry ; Cell Line, Tumor ; Colonic Neoplasms/*drug therapy ; Drug Carriers/*chemistry ; Drug Delivery Systems ; Escherichia coli/*chemistry ; Fluorouracil/*administration & dosage/therapeutic use ; Humans ; Mice, Inbred BALB C ; Silicon Dioxide/chemistry ; }, abstract = {AIM: In this study, 5-fluorouracil (5-FU) is delivered to target colon without the interference of mononuclear phagocyte system (MPS).

METHODS: Outer membrane vesicles (OMVs) were used as the biological shield to disguise mesoporous silica (MSN) and 5-FU. OMVs-MSN-5-FU were prepared by high pressure co-extrusion, and characterised on the basis of size, drug loading, transmission electron microscope, infra-red spectroscopy, differential scanning calorimetry, thermal gravity analysis, % in vitro release, MTT assay, cell uptake and in vivo imaging.

RESULTS: OMVs-MSN-5-FU with -18.22 ± 0.17 mV zeta potential and 90.4 ± 9.1 nm size were used for oral treatment of colon cancer. Drug loading of the drug was 50.22%±0.17 (w/w). The cumulative release of OMVs-MSN-5-FU reached 75.07%±0.94 in tumour microenvironment. The percentage of cell viability of OMVs-MSN-5-FU was 33.75%±2.73. In vivo experiments results confirmed that OMVs-MSN-5-FU could be taken up by colon cancer cells.

CONCLUSIONS: The study provided a promising nano platform for the targeting treatment of colon cancer.}, } @article {pmid32700468, year = {2020}, author = {Wang, S and Zhi, L and Shan, W and Lu, H and Xu, Q and Li, J}, title = {Correlation of extracellular polymeric substances and microbial community structure in denitrification biofilm exposed to adverse conditions.}, journal = {Microbial biotechnology}, volume = {13}, number = {6}, pages = {1889-1903}, pmid = {32700468}, issn = {1751-7915}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Extracellular Polymeric Substance Matrix ; *Microbiota ; Nitrogen ; }, abstract = {Microbial community may respond to different adverse conditions and result in the variation of extracellular polymeric substances (EPS) in denitrification biofilm; this study discovered the role of EPS in accordance with the analysis of cyclic diguanylate (c-di-GMP) and electron equilibrium (EE) under low organic loading rate, shock organic loading rate and low temperature conditions. Good nitrate removal performance could be achieved under shock organic loading rate and low temperature conditions; however, owing to the low organic loading rate, the carbon source was preferentially utilized for biomass growth. Tightly bound EPS (TB-EPS) contents progressively increased and facilitated cell adhesion and biofilm formation. The stable TB protein (TB-PN) content in TB-EPS built a cross-linked network to maintain internal biofilm structure and led to the rapid biosynthesis of polysaccharides, which could further enhance microbial adhesion and improve nitrate removal. C-di-GMP played an important role in biomass retention and biofilm formation, based on the correlation analysis of c-di-GMP and EPS. TB polysaccharide (TB-PS) contents presented a significant positive correlation with c-di-GMP content, microbial adhesion and biofilm stabilization was further enhanced through c-di-GMP regulation. In addition, a remarkable negative correlation between electron deletion rate (EDR) and TB-PN and TB-PS was discovered, and TB-PS was required to serve as energy source to enhance denitrification according to EE analysis. Surprisingly, dynamic microbial community was observed due to the drastic community succession under low temperature conditions, and the discrepancy between the dominant species for denitrification was found under shock organic loading rate and low temperature conditions. The notable increase in bacterial strains Simlicispira, Pseudomonas and Chryseobacterium was conducive to biofilm formation and denitrification under shock organic loading rate, while Dechloromonas and Zoogloea dramatically enriched for nitrate removal under low temperature conditions. The high abundance of Dechloromonas improved the secretion of EPS through the downstream signal transduction, and the c-di-GMP conserved in Pseudomonas concurrently facilitated to enhance exopolysaccharide production to shock organic loading rate and low temperature conditions.}, } @article {pmid32700454, year = {2020}, author = {Chen, L and Li, H and Wen, H and Zhao, B and Niu, Y and Mo, Q and Wu, Y}, title = {Biofilm formation in Acinetobacter baumannii was inhibited by PAβN while it had no association with antibiotic resistance.}, journal = {MicrobiologyOpen}, volume = {9}, number = {9}, pages = {e1063}, pmid = {32700454}, issn = {2045-8827}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification/*physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Dipeptides/*pharmacology ; Drug Resistance, Bacterial/genetics ; Gene Expression ; Genotype ; Humans ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; }, abstract = {This study was conducted to investigate the relationship between Acinetobacter baumannii biofilm formation and antibiotic resistance. Furthermore, the effects of PAβN, a potential efflux pump inhibitor, on A. baumannii biofilm formation and dispersion were tested, and the gene expression levels of efflux pumps were determined to study the mechanisms. A total of 92 A. baumannii isolates from infected patients were collected and identified by multiplex PCR. The antimicrobial susceptibility of A. baumannii clinical isolates was tested by VITEK 2 COMPACT[®] . Genotypes were determined by ERIC-2 PCR. Biofilm formation and dispersion were detected by crystal violet staining. The presence and mRNA expression of efflux pump genes were analyzed by conventional PCR and real-time PCR, respectively. More than 50% of the A. baumannii strains formed biofilm and were divided into different groups according to their biofilm-forming ability. Antibiotic resistance rates among most groups did not significantly differ. There were 7 clonal groups in 92 strains of A. baumannii and no dominant clones among the different biofilm-forming groups. PAβN inhibited A. baumannii biofilm formation and enhanced its dispersion, whereas adeB, adeJ, and adeG and the mRNA expression of adeB, abeM, and amvA showed no differences in the different biofilm-forming groups. In conclusion, there was no clear relationship between biofilm formation and antibiotic resistance in A. baumannii. The effects of PAβN on A. baumannii biofilm formation and dispersion were independent of the efflux pumps.}, } @article {pmid32700202, year = {2021}, author = {Romero, MC and Ramos, G and González, I and Ramírez, F}, title = {A Novel Method to Reveal a Ureolytic Biofilm Attachment and In Situ Growth Monitoring by Electrochemical Impedance Spectroscopy.}, journal = {Applied biochemistry and biotechnology}, volume = {193}, number = {5}, pages = {1379-1396}, pmid = {32700202}, issn = {1559-0291}, mesh = {Ammonium Compounds/metabolism ; *Biofilms ; Electric Capacitance ; Electric Impedance ; Microscopy, Electron, Scanning ; }, abstract = {The formation of biofilms capable of efficiently carrying out ureolysis is of fundamental importance in several biotechnological systems such as urinary tract infections, building materials and municipal wastewater treatment. This work proposes a straightforward method for the formation of a ureolytic biofilm attached to graphite. The proposed strategy reduced the time needed to complete ureolysis to 3 days instead of 16 days required in suspension culture. To confirm the formation of a ureolytic biofilm, scanning electron microscopy and confocal laser scanning microscopy studies were employed ex situ. However, it is imperative to analyse the biofilm by direct non-invasive techniques. Accordingly, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were used as in situ monitoring techniques. The reduction in OCP from - 0.01 to - 0.2 V vs. Ag/AgCl and the increase in capacitance from 200 to 260 μF cm[-2] were related to biofilm attachment. To the best of our knowledge, this is the first time in which a ureolytic biofilm attachment has been analysed by EIS. The increase in the biomass from 0.04 to 2.81 μm[3] μm[-2] and in average thickness from 10.19 to 32.78 μm was related to biofilm maturation.}, } @article {pmid32699922, year = {2021}, author = {Hwang, HY and Kim, HE}, title = {Influence of a novel pH-cycling model using dental microcosm biofilm on the remineralizing efficacy of fluoride in early carious lesions.}, journal = {Clinical oral investigations}, volume = {25}, number = {1}, pages = {337-344}, pmid = {32699922}, issn = {1436-3771}, support = {NRF-2019R1F1A1058152//National Research Foundation of Korea/ ; }, mesh = {Animals ; Biofilms ; Cariostatic Agents/pharmacology ; Cattle ; *Dental Caries/drug therapy/prevention & control ; Dental Enamel ; *Fluorides ; Humans ; Hydrogen-Ion Concentration ; Tooth Remineralization ; }, abstract = {OBJECTIVES: To evaluate the remineralizing efficacy of fluoride in early carious lesions using a novel microbial pH-cycling model that combines the chemical pH-cycling model with dental microcosm biofilms.

MATERIALS AND METHODS: Artificial carious lesions were formed in 48 bovine incisors. The chemical and microbial pH-cycling models were applied to 24 specimens, respectively; the latter was applied after formation of dental microcosm biofilms for 6 days, based on the human saliva inoculation. The pH-cycling schedule was repeated for 12 days. All specimens were evaluated for fluorescence loss (ΔF) using quantitative light-induced fluorescence-digital before and after the pH-cycling. Specimen biofilms were further analyzed for red/green values (R/G ratios) and colony-forming units (CFUs). One-way analysis of variance and Tukey's post hoc analysis were used to analyze change in fluorescence loss (ΔΔF) according to the pH-cycling model and treatment.

RESULTS: When the chemical pH-cycling and microbial pH-cycling models were used, ΔΔF was 1.36 (p = 0.008) and 1.17 (p > 0.05) times higher, respectively, in the fluoride-treated group than that in the distilled water-treated group. In the microbial pH-cycling model, R/G ratios and CFU counts of biofilms were not significantly different between treatments (p > 0.05).

CONCLUSIONS: No significant difference was observed in the remineralizing efficacy of fluoride according to the presence of dental biofilms covering early carious lesions.

CLINICAL RELEVANCE: The remineralizing efficacy of fluoride could be overestimated in the absence of dental biofilms. Therefore, for accurate evaluation of the clinical value of remineralizing agents, dental biofilms should be included in in vitro tests.}, } @article {pmid32699879, year = {2021}, author = {Cano, EJ and Caflisch, KM and Bollyky, PL and Van Belleghem, JD and Patel, R and Fackler, J and Brownstein, MJ and Horne, B and Biswas, B and Henry, M and Malagon, F and Lewallen, DG and Suh, GA}, title = {Phage Therapy for Limb-threatening Prosthetic Knee Klebsiella pneumoniae Infection: Case Report and In Vitro Characterization of Anti-biofilm Activity.}, journal = {Clinical infectious diseases : an official publication of the Infectious Diseases Society of America}, volume = {73}, number = {1}, pages = {e144-e151}, pmid = {32699879}, issn = {1537-6591}, support = {R01 AR056647/AR/NIAMS NIH HHS/United States ; UL1 TR002377/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/therapeutic use ; *Arthroplasty, Replacement, Knee/adverse effects ; Biofilms ; Humans ; Klebsiella pneumoniae ; Male ; Middle Aged ; *Phage Therapy ; *Prosthesis-Related Infections/drug therapy ; }, abstract = {BACKGROUND: Prosthetic joint infection (PJI) is a potentially limb-threatening complication of total knee arthroplasty. Phage therapy is a promising strategy to manage such infections including those involving antibiotic-resistant microbes, and to target microbial biofilms. Experience with phage therapy for infections associated with retained hardware is limited. A 62-year-old diabetic man with a history of right total knee arthroplasty 11 years prior who had suffered multiple episodes of prosthetic knee infection despite numerous surgeries and prolonged courses of antibiotics, with progressive clinical worsening and development of severe allergies to antibiotics, had been offered limb amputation for persistent right prosthetic knee infection due to Klebsiella pneumoniae complex. Intravenous phage therapy was initiated as a limb-salvaging intervention.

METHODS: The patient received 40 intravenous doses of a single phage (KpJH46Φ2) targeting his bacterial isolate, alongside continued minocycline (which he had been receiving when he developed increasing pain, swelling, and erythema prior to initiation of phage therapy). Serial cytokine and biomarker measurements were performed before, during, and after treatment. The in vitro anti-biofilm activity of KpJH46Φ2, minocycline and the combination thereof was evaluated against a preformed biofilm of the patient's isolate and determined by safranin staining.

RESULTS: Phage therapy resulted in resolution of local symptoms and signs of infection and recovery of function. The patient did not experience treatment-related adverse effects and remained asymptomatic 34 weeks after completing treatment while still receiving minocycline. A trend in biofilm biomass reduction was noted 22 hours after exposure to KpJH46Φ2 (P = .063). The addition of phage was associated with a satisfactory outcome in this case of intractable biofilm-associated prosthetic knee infection. Pending further studies to assess its efficacy and safety, phage therapy holds promise for treatment of device-associated infections.}, } @article {pmid32699383, year = {2020}, author = {Levipan, HA and Irgang, R and Yáñez, A and Avendaño-Herrera, R}, title = {Improved understanding of biofilm development by Piscirickettsia salmonis reveals potential risks for the persistence and dissemination of piscirickettsiosis.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {12224}, pmid = {32699383}, issn = {2045-2322}, mesh = {Animals ; Aquaculture/methods ; Biofilms/*growth & development ; Cell Line ; Chile ; Fish Diseases/microbiology ; Genotype ; Head Kidney/microbiology ; Piscirickettsia/genetics/*growth & development ; Piscirickettsiaceae Infections/*microbiology ; Salmo salar/microbiology ; }, abstract = {Piscirickettsia salmonis is the causative agent of piscirickettsiosis, a disease with high socio-economic impacts for Chilean salmonid aquaculture. The identification of major environmental reservoirs for P. salmonis has long been ignored. Most microbial life occurs in biofilms, with possible implications in disease outbreaks as pathogen seed banks. Herein, we report on an in vitro analysis of biofilm formation by P. salmonis Psal-103 (LF-89-like genotype) and Psal-104 (EM-90-like genotype), the aim of which was to gain new insights into the ecological role of biofilms using multiple approaches. The cytotoxic response of the salmon head kidney cell line to P. salmonis showed interisolate differences, depending on the source of the bacterial inoculum (biofilm or planktonic). Biofilm formation showed a variable-length lag-phase, which was associated with wider fluctuations in biofilm viability. Interisolate differences in the lag phase emerged regardless of the nutritional content of the medium, but both isolates formed mature biofilms from 288 h onwards. Psal-103 biofilms were sensitive to Atlantic salmon skin mucus during early formation, whereas Psal-104 biofilms were more tolerant. The ability of P. salmonis to form viable and mucus-tolerant biofilms on plastic surfaces in seawater represents a potentially important environmental risk for the persistence and dissemination of piscirickettsiosis.}, } @article {pmid32697076, year = {2020}, author = {Ray, A and Edmonds, KA and Palmer, LD and Skaar, EP and Giedroc, DP}, title = {Staphylococcus aureus Glucose-Induced Biofilm Accessory Protein A (GbaA) Is a Monothiol-Dependent Electrophile Sensor.}, journal = {Biochemistry}, volume = {59}, number = {31}, pages = {2882-2895}, pmid = {32697076}, issn = {1520-4995}, support = {R01 AI069233/AI/NIAID NIH HHS/United States ; F32 AI122516/AI/NIAID NIH HHS/United States ; T32 HL094296/HL/NHLBI NIH HHS/United States ; R01 AI073843/AI/NIAID NIH HHS/United States ; R35 GM118157/GM/NIGMS NIH HHS/United States ; K99 HL143441/HL/NHLBI NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Bacterial Proteins/chemistry/*metabolism ; Biofilms ; Fluorescence Polarization ; Models, Molecular ; Operon/genetics ; Protein Conformation ; Staphylococcus aureus/genetics/*metabolism/physiology ; Sulfhydryl Compounds/*metabolism ; }, abstract = {Staphylococcus aureus is a commensal pathogen that has evolved to protect itself from unfavorable conditions by forming complex community structures termed biofilms. The regulation of the formation of these structures is multifactorial and in S. aureus involves a number of transcriptional regulators. GbaA (glucose-induced biofilm accessory protein A) is a tetracycline repressor (TetR) family regulator that harbors two conserved Cys residues (C55 and C104) and impacts the regulation of formation of poly-N-acetylglucosamine-based biofilms in many methicillin-resistant S. aureus (MRSA) strains. Here, we show that GbaA-regulated transcription of a divergently transcribed operon in a MRSA strain can be induced by potent electrophiles, N-ethylmaleimide and methylglyoxal. Strikingly, induction of transcription in cells requires C55 or C104, but not both. These findings are consistent with in vitro small-angle X-ray scattering, chemical modification, and DNA operator binding experiments, which reveal that both reduced and intraprotomer (C55-C104) disulfide forms of GbaA have very similar overall structures and each exhibits a high affinity for the DNA operator, while DNA binding is strongly inhibited by derivatization of one or the other Cys residues via formation of a mixed disulfide with bacillithiol disulfide or a monothiol derivatization adduct with NEM. While both Cys residues are reactive toward electrophiles, C104 in the regulatory domain is the more reactive thiolate. These characteristics enhance the inducer specificity of GbaA and would preclude sensing of generalized cellular oxidative stress via disulfide bond formation. The implications of the findings for GbaA function in MRSA strains are discussed.}, } @article {pmid32696587, year = {2020}, author = {Goudarzi, H and Goudarzi, M and Sabzehali, F and Fazeli, M and Salimi Chirani, A}, title = {Genetic analysis of methicillin-susceptible Staphylococcus aureus clinical isolates: High prevalence of multidrug-resistant ST239 with strong biofilm-production ability.}, journal = {Journal of clinical laboratory analysis}, volume = {34}, number = {11}, pages = {e23494}, pmid = {32696587}, issn = {1098-2825}, support = {20515//Shahid Beheshti University of Medical Sciences/ ; }, mesh = {Biofilms ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial/*genetics ; Humans ; Iran ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Multilocus Sequence Typing ; *Staphylococcal Infections/epidemiology/microbiology ; *Staphylococcus aureus/drug effects/genetics/pathogenicity ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: The distributions of methicillin-susceptible Staphylococcus aureus (MSSA) are divers geographically with different genetic backgrounds. Data related to molecular characteristics of MSSA compare to methicillin-resistant Staphylococcus aureus (MRSA) is sparse.

METHODS: In this cross-sectional study, antimicrobial susceptibility testing, virulence genes analysis, biofilm formation, accessory gene regulator (agr) typing, and multilocus sequence typing (MLST) characterized on 75 MSSA isolates.

RESULTS: Multidrug-resistance MSSA was found to be 84%. Forty-eight (64%) isolates were toxinogenic with 34 and 14 isolates carrying pvl and tst representing 45.3% and 18.7%. The most common SE genes were sed (20%), sec (16%), and sea (16%). Fifty-five (73.3%) isolates were confirmed as biofilm producer with a markedly high prevalence of fnbA (93.3%), fnbB (86.7%), icaA (65.3%), icaD (53.3%), can (24%), ebp (10.7%), and bap (1.3%). A total of 3 agr types (I, 73.3%; III, 16%; II, 10.7%) and 4 clonal complexes (CCs) and sequence types (STs), namely CC8/ST293 (45.3%), CC/ST22 (28%), CC/ST30 (16%), and CC/ST5 (10.7%) were detected in this study. All the high and low-level mupirocin resistance strains belonged to ST239 and ST22 strains, respectively. All the fusidic acid-resistant isolates carried fusC and belonged to ST30.

CONCLUSIONS: These findings indicated that ST239 with strong biofilm production ability is the most common type in MSSA strains isolated from patients. It seems that the antimicrobial resistance profiles, toxin, and biofilm formation were closely associated with specific STs. Further studies are required to identify and control of these clonal lineages in our area.}, } @article {pmid32696279, year = {2020}, author = {Çam, S and Brinkmeyer, R}, title = {Differential expression of vvhA and CPS operon allele 1 genes in Vibrio vulnificus under biofilm and planktonic conditions.}, journal = {Antonie van Leeuwenhoek}, volume = {113}, number = {10}, pages = {1437-1446}, doi = {10.1007/s10482-020-01452-z}, pmid = {32696279}, issn = {1572-9699}, mesh = {Alleles ; Bacterial Proteins/*genetics ; *Biofilms ; *Gene Expression Regulation, Bacterial ; Humans ; Kinetics ; Vibrio vulnificus/*genetics/*growth & development ; }, abstract = {Examination of genes encoding for the virulence factors, hemolysin/cytolysin (vvhA) and capsular polysaccharide (CPS allele 1), during biofilm formation revealed that their expression was influenced by the maturity of the biofilm as well as by temperature. At 24 °C, expression of vvhA during biofilm formation was low between 4 and 12 h but increased 10-fold by 24 h to (5.1 × 10[4] ± 6.3 × 10[3]mRNA copies/ml) as the biofilm matured. Compared to planktonic cells, expression of vvhA during biofilm formation at 24 °C was initially up-regulated at 4 h (1.07 ± 0.00-fold) but then was down-regulated almost four-fold during the intermediate and mature stages of biofilm formation. In contrast, vvhA expression at 37 °C was up-regulated almost four-fold in the early stages (4 and 6 h) of biofilm formation and remained two-fold up-regulated by 24 h even as the biofilm was deteriorating. CPS allele 1 expression at 24 °C during biofilm formation was up-regulated (1.50 ± 0.18-fold) during the initial attachment phase of the cells but was strongly down-regulated during the intermediate phases at 8 and 10 h (74.42 ± 42.16-fold and 453.76 ± 193.32-fold, respectively), indicating that capsular polysaccharide (CPS) is not important to intermediate biofilm architecture. Interestingly, as the biofilm matured by 24 h, expression of CPS allele 1 was again up-regulated (1.88 ± 1.07), showing that CPS plays a role in mature biofilm. At 37 °C, CPS allele 1 expression was significantly up-regulated (up to 10[5]) during biofilm formation, indicating that the biofilm form of V. vulnificus may be preferred over the planktonic form in the human host.}, } @article {pmid32695305, year = {2020}, author = {da Silva, FA and Medeiros, SMFRDS and da Costa-Junior, SD and Roberto, AEM and Palácio, SB and de Lima-Neto, RG and Neves, RP and Magalhães, CP and Garcia, JE and Cavalcanti, IMF}, title = {Antimicrobial Resistance Profile and Biofilm Production of Microorganisms Isolated from Oropharynx of Rupornis magnirostris (Gmelin, 1788) and Caracara plancus (Miller, 1777).}, journal = {Veterinary medicine international}, volume = {2020}, number = {}, pages = {8888618}, pmid = {32695305}, issn = {2090-8113}, abstract = {The aim of this preliminary study was to identify microorganisms with antimicrobial resistance profile and biofilm producers in oropharynx of Rupornis magnirostris and Caracara plancus. Six R. magnirostris and six C. plancus maintained in Triage Center for Wild Animals (CETAS) facilities were studied. Coagulase-positive staphylococci (CoPS), enterobacteria, and yeasts were identified by the biochemical analysis or MALDI-TOF mass spectrometry. The resistance profile of the microorganisms was analyzed according to CLSI. The biofilm production was evaluated by Congo red and violet crystal staining methods. Among the 12 birds, 10 presented strains of CoPS and/or enterobacteria with resistance profile, such as methicillin-resistant CoPS (MR-CoPS), vancomycin-resistant CoPS (VR-CoPS), extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL), and Klebsiella pneumoniae carbapenemase- (KPC-) producing bacteria. Regards the fungal analysis, Candida spp., Cryptococcus spp., Rhodotorula mucilaginosa, R. glutinis, and Trichosporon coremiiforme were identified. All the Trichosporon coremiiforme strains were resistant to amphotericin B, as well as all the Rhodotorula mucilaginosa exhibited resistance to fluconazole. Related to the biofilm production, among the 8 CoPS, 27 enterobacteria, and 10 yeasts isolates, 3, 16, and 7 strains were biofilm producers, respectively. Thus, the presence of these microorganisms in birds of prey is worrisome, highlighting its possible influence in the spread of infections in urban centers.}, } @article {pmid32693267, year = {2020}, author = {Jiang, M and Zheng, J and Perez-Calleja, P and Picioreanu, C and Lin, H and Zhang, X and Zhang, Y and Li, H and Nerenberg, R}, title = {New insight into CO2-mediated denitrification process in H2-based membrane biofilm reactor: An experimental and modeling study.}, journal = {Water research}, volume = {184}, number = {}, pages = {116177}, doi = {10.1016/j.watres.2020.116177}, pmid = {32693267}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors ; Carbon Dioxide ; *Denitrification ; Nitrates ; }, abstract = {The H2-based membrane biofilm reactor (H2-MBfR) is an emerging technology for removal of nitrate (NO3[-]) in water supplies. In this research, a lab-scale H2-MBfR equipped with a separated CO2 providing system and a microsensor measuring unit was developed for NO3[-] removal from synthetic groundwater. Experimental results show that efficient NO3[-] reduction with a flux of 1.46 g/(m[2]⋅d) was achieved at the optimal operating conditions of hydraulic retention time (HRT) 80 min, influent NO3[-] concentration 20 mg N/L, H2 pressure 5 psig and CO2 addition 50 mg/L. Given the complex counter-diffusion of substrates in the H2-MBfR, mathematical modeling is a key tool to both understand its behavior and optimize its performance. A sophisticated model was successfully established, calibrated and validated via comparing the measured and simulated system performance and/or substrate gradients within biofilm. Model results indicate that i) even under the optimal operating conditions, denitrifying bacteria (DNB) in the interior and exterior of biofilm suffered low growth rate, attributed to CO2 and H2 limitation, respectively; ii) appropriate operating parameters are essential to maintaining high activity of DNB in the biofilm; iii) CO2 concentration was the decisive factor which matters its dominant role in mediating hydrogenotrophic denitrification process; iv) the predicted optimum biofilm thickness was 650 µm that can maximize the denitrification flux and prevent loss of H2.}, } @article {pmid32692259, year = {2020}, author = {Strateva, T and Trifonova, A and Savov, E and Mitov, I and Peykov, S}, title = {Characterization of an extensively drug-resistant Stenotrophomonas maltophilia clinical isolate with strong biofilm formation ability from Bulgaria.}, journal = {Infectious diseases (London, England)}, volume = {52}, number = {11}, pages = {841-845}, doi = {10.1080/23744235.2020.1792545}, pmid = {32692259}, issn = {2374-4243}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Bulgaria ; *Gram-Negative Bacterial Infections ; Humans ; Stenotrophomonas maltophilia/*drug effects/isolation & purification ; }, } @article {pmid32691665, year = {2021}, author = {Jiménez Hernández, M and Soriano, A and Filella, X and Calvo, M and Coll, E and Rebled, JM and Poch, E and Graterol, F and Compte, MT and Maduell, F and Fontsere, N}, title = {Impact of locking solutions on conditioning biofilm formation in tunnelled haemodialysis catheters and inflammatory response activation.}, journal = {The journal of vascular access}, volume = {22}, number = {3}, pages = {370-379}, doi = {10.1177/1129729820942040}, pmid = {32691665}, issn = {1724-6032}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Infective Agents/*administration & dosage/adverse effects ; Anticoagulants/*administration & dosage/adverse effects ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/diagnosis/microbiology/*prevention & control ; *Catheters, Indwelling ; Citric Acid/*administration & dosage/adverse effects ; Equipment Design ; Female ; Heparin/*administration & dosage/adverse effects ; Humans ; Inflammation/blood/etiology/*prevention & control ; Inflammation Mediators/blood ; Interleukin-6/blood ; Male ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Middle Aged ; Pilot Projects ; Prospective Studies ; Renal Dialysis/adverse effects/*instrumentation ; Surface Properties ; Taurine/administration & dosage/adverse effects/*analogs & derivatives ; Thiadiazines/*administration & dosage/adverse effects ; Time Factors ; Treatment Outcome ; }, abstract = {INTRODUCTION: The surface of tunnelled cuffed catheters provides an optimal environment for the development of biofilms, which have recently been described as conditioning films because of the presence of adherent biological materials. These biofilms are associated with infection and thrombosis and potentially increase patients' inflammatory response. These complications could be reduced by the use of locking solutions.

OBJECTIVE: To analyse biofilm formation, using confocal and electron microscopy, in tunnelled cuffed catheters locked with three different solutions and to determine the relationship between these solutions and inflammatory response.

STUDY DESIGN: This prospective study included 35 haemodialysis patients with tunnelled cuffed catheter removal for non-infection-related reasons. The participants were divided into three groups according to the lock solution used: (1) heparin 1: 5000 IU; (2) citrate 4%; and (3) taurolidine 1.35%, citrate 4% and heparin 500 IU (taurolock); in the latter group, 25,000 IU taurolidine-urokinase was used in the last weekly session. All tunnelled cuffed catheters were cultured, and the inner surface was evaluated with confocal and electron microscopy. The inflammatory profile of included patients was determined at tunnelled cuffed catheter removal.

RESULTS: There were no differences in clinical or demographic variables between the three subgroups. Biofilm thickness was lower in the taurolidine group than in the citrate 4% and heparin groups (28.85 ± 6.86 vs 49.99 ± 16.56 vs 56.2 ± 15.67 µm, respectively; p < 0.001), as was biofilm volume (1.01 ±1.18 vs 3.7 ± 2.15 vs 5.55 ±2.44, µm[3], respectively; p < 0.001). The mean interleukin-6 value was 39%, which was 50% lower than in the citrate and heparin groups, but without significance differences.

CONCLUSION: Our results show that biofilms were found in all tunnelled cuffed catheters, but the thickness and volume were significantly lower in tunnelled cuffed catheters locked with taurolidine solution. Therefore, the type of locking solution used in tunnelled cuffed catheters should maintain tunnelled cuffed catheter sterility and prevent catheter-related bloodstream infections. No significant difference was observed in the inflammatory profile according to the type of locking solution.}, } @article {pmid32691440, year = {2020}, author = {Wu, YF and Lee, TY and Liao, WT and Chuan, HH and Cheng, NC and Cheng, CM}, title = {Rapid detection of biofilm with modified alcian blue staining: In-vitro protocol improvement and validation with clinical cases.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {28}, number = {6}, pages = {834-843}, doi = {10.1111/wrr.12845}, pmid = {32691440}, issn = {1524-475X}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Alcian Blue/*pharmacokinetics ; Bacteria/*growth & development/ultrastructure ; *Biofilms ; Coloring Agents/pharmacology ; Follow-Up Studies ; Humans ; Microscopy, Electron, Scanning ; Middle Aged ; Staining and Labeling/*methods ; Wound Healing/*physiology ; Wound Infection/*diagnosis/microbiology ; Young Adult ; }, abstract = {For chronic wounds, biofilm infection is a critical issue because it can tip the scales toward an unhealing state. Biofilm-based wound therapy has been extensively advocated. However, point-of-care biofilm diagnosis still largely relies on clinical judgment. In this study, we aimed to develop a rapid tool for diagnosing wound biofilm presence by alcian blue staining. First, we sought to optimize alcian blue staining using a colorimetric-based approach to detect the biofilm, specifically targeting polysaccharides in the extracellular polymeric substances. Among examined transfer membranes and cationic detergents at various concentrations, we selected a positively charged nylon transfer membrane for sample loading, and 1% cetyl trimethyl ammonium chloride (CTAC) as the blocking solution. After sample loading and blocking, the membrane was immersed in alcian blue solution for staining, followed by immersion in 1% CTAC to decrease background noise. Each step required only 30 seconds, and the whole procedure was completed within a few minutes. In the second part of this study, we enrolled 31 patients with chronic wounds to investigate the predictive validity of biofilm detection for unhealed wounds at a 1-month follow-up visit. Among the 18 cases with positive wound biofilm staining, 15 wounds (83.3%) were not healed at the 1-month follow-up visit. Only three unhealed wounds (30%) produced in negative staining cases. This finding indicates that biofilm infection is associated with poor healing outcome for chronic wounds. Moreover, our staining results correlated well with the clinical microbiological culture assessment (83.9% consistency; 95.2% sensitivity, and 60% specificity). In conclusion, the modified alcian blue staining protocol used here represents a rapid and sensitive procedure for detecting biofilm in chronic wounds. This technique provides a practical point-of-care approach for detection of wound biofilm, the implementation of which may improve clinical outcomes for chronic wound patients. Additional studies are required to validate this method.}, } @article {pmid32691297, year = {2020}, author = {Alawadhi, NB and Lippert, F and Gregory, RL}, title = {Effects of casein phosphopeptide-amorphous calcium phosphate crème on nicotine-induced Streptococcus mutans biofilm in vitro.}, journal = {Clinical oral investigations}, volume = {24}, number = {10}, pages = {3513-3518}, doi = {10.1007/s00784-020-03221-8}, pmid = {32691297}, issn = {1436-3771}, mesh = {Biofilms ; Calcium Phosphates ; Caseins ; Nicotine ; Phosphopeptides ; *Streptococcus mutans ; }, abstract = {OBJECTIVES: The aim of this study was to test the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) crème, or MI Paste™ (MIP), on nicotine-induced Streptococcus mutans biofilm. The experiment utilized S. mutans biofilm assays with varying concentrations of nicotine and MIP aqueous concentrate levels. First hand exposure to nicotine has been demonstrated to significantly increase S. mutans biofilm formation, while the active component, CPP-ACP, in MIP has been shown to reduce S. mutans biofilm formation.

MATERIALS AND METHODS: A 24-h culture of S. mutans UA159 in microtiter plates were treated with varying nicotine concentrations (0-32 mg/ml) in Tryptic Soy Broth supplemented with 1% sucrose (TSBS) with or without MIP aqueous concentrate. A spectrophotometer was used to determine total growth absorbance and planktonic growth. The microtiter plate wells were washed, fixed, and stained with crystal violet dye and the absorbance measured to determine biofilm formation.

RESULTS: The presence of MIP aqueous concentrate inhibits nicotine-induced S. mutans biofilm formation at different concentrations of nicotine (0-32 mg/ml).

CONCLUSION: The results demonstrated nicotine-induced S. mutans biofilm formation is decreased in the presence of MIP. This provides further evidence about the cariostatic properties of CPP-ACP, the active soluble ingredient in the MIP, and reconfirms the harmful effects of nicotine.

CLINICAL SIGNIFICANCE: Smokers may gain dual benefits from the use of MIP, as a remineralization agent and as a cariostatic agent, by inhibiting nicotine-induced S. mutans biofilm formation.}, } @article {pmid32690651, year = {2020}, author = {Maisuria, VB and Hosseinidoust, Z and Tufenkji, N}, title = {Correction for Maisuria et al., "Polyphenolic Extract from Maple Syrup Potentiates Antibiotic Susceptibility and Reduces Biofilm Formation of Pathogenic Bacteria".}, journal = {Applied and environmental microbiology}, volume = {86}, number = {15}, pages = {}, doi = {10.1128/AEM.01341-20}, pmid = {32690651}, issn = {1098-5336}, } @article {pmid32690648, year = {2020}, author = {Min, JG and Sanchez Rangel, UJ and Franklin, A and Oda, H and Wang, Z and Chang, J and Fox, PM}, title = {Topical Antibiotic Elution in a Collagen-Rich Hydrogel Successfully Inhibits Bacterial Growth and Biofilm Formation In Vitro.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {10}, pages = {}, pmid = {32690648}, issn = {1098-6596}, mesh = {Animals ; *Anti-Bacterial Agents/pharmacology ; Biofilms ; Collagen ; Humans ; *Hydrogels ; Pseudomonas aeruginosa ; }, abstract = {Chronic wounds are a prominent concern, accounting for $25 billion of health care costs annually. Biofilms have been implicated in delayed wound closure, but they are susceptible to developing antibiotic resistance and treatment options continue to be limited. A novel collagen-rich hydrogel derived from human extracellular matrix presents an avenue for treating chronic wounds by providing appropriate extracellular proteins for healing and promoting neovascularization. Using the hydrogel as a delivery system for localized secretion of a therapeutic dosage of antibiotics presents an attractive means of maximizing delivery while minimizing systemic side effects. We hypothesize that the hydrogel can provide controlled elution of antibiotics leading to inhibition of bacterial growth and disruption of biofilm formation. The rate of antibiotic elution from the collagen-rich hydrogel and the efficacy of biofilm disruption was assessed with Pseudomonas aeruginosa Bacterial growth inhibition, biofilm disruption, and mammalian cell cytotoxicity were quantified using in vitro models. The antibiotic-loaded hydrogel showed sustained release of antibiotics for up to 24 h at therapeutic levels. The treatment inhibited bacterial growth and disrupted biofilm formation at multiple time points. The hydrogel was capable of accommodating various classes of antibiotics and did not result in cytotoxicity in mammalian fibroblasts or adipose stem cells. The antibiotic-loaded collagen-rich hydrogel is capable of controlled antibiotic release effective for bacteria cell death without native cell death. A human-derived hydrogel that is capable of eluting therapeutic levels of antibiotic is an exciting prospect in the field of chronic wound healing.}, } @article {pmid32689917, year = {2020}, author = {Collins, AJ and Smith, TJ and Sondermann, H and O'Toole, GA}, title = {From Input to Output: The Lap/c-di-GMP Biofilm Regulatory Circuit.}, journal = {Annual review of microbiology}, volume = {74}, number = {}, pages = {607-631}, pmid = {32689917}, issn = {1545-3251}, support = {R01 GM123609/GM/NIGMS NIH HHS/United States ; T32 AI007519/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/metabolism ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Pseudomonas fluorescens/*genetics/*metabolism ; }, abstract = {Biofilms are the dominant bacterial lifestyle. The regulation of the formation and dispersal of bacterial biofilms has been the subject of study in many organisms. Over the last two decades, the mechanisms of Pseudomonas fluorescens biofilm formation and regulation have emerged as among the best understood of any bacterial biofilm system. Biofilm formation by P. fluorescens occurs through the localization of an adhesin, LapA, to the outer membrane via a variant of the classical type I secretion system. The decision between biofilm formation and dispersal is mediated by LapD, a c-di-GMP receptor, and LapG, a periplasmic protease, which together control whether LapA is retained or released from the cell surface. LapA localization is also controlled by a complex network of c-di-GMP-metabolizing enzymes. This review describes the current understanding of LapA-mediated biofilm formation by P. fluorescens and discusses several emerging models for the regulation and function of this adhesin.}, } @article {pmid32687650, year = {2021}, author = {Nowak, J and Visnovsky, SB and Cruz, CD and Fletcher, GC and van Vliet, AHM and Hedderley, D and Butler, R and Flint, S and Palmer, J and Pitman, AR}, title = {Inactivation of the gene encoding the cationic antimicrobial peptide resistance factor MprF increases biofilm formation but reduces invasiveness of Listeria monocytogenes.}, journal = {Journal of applied microbiology}, volume = {130}, number = {2}, pages = {464-477}, doi = {10.1111/jam.14790}, pmid = {32687650}, issn = {1365-2672}, support = {CAWX1317//New Zealand Ministry of Business, Innovation and Employment/ ; }, mesh = {Antimicrobial Cationic Peptides/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Caco-2 Cells ; Drug Resistance, Bacterial/*genetics ; Humans ; Listeria monocytogenes/drug effects/genetics/pathogenicity/*physiology ; Mutation ; Virulence/genetics ; }, abstract = {AIMS: To understand the genetics involved in surface attachment and biofilm formation of Listeria monocytogenes.

METHODS AND RESULTS: An in vitro screen of a Himar1 transposon library of L. monocytogenes strain 15G01 identified three transposants that produced significantly different biofilm levels when compared to the wild-type strain; two mutants exhibited enhanced biofilm formation and one produced less biofilm biomass than the wild-type. The mutant 15G01 mprF::Himar1, which had a transposon insertion in the mprF gene, was selected for further analysis. The mutant produced a more densely populated biofilm on solid surfaces such as stainless steel and polystyrene, as determined using scanning electron and light microscopy. The 15G01 mprF::Himar1 mutant remained viable in biofilms, but showed an increase in sensitivity to the cationic antimicrobial gallidermin. The mutant also displayed reduced invasiveness in CaCo-2 intestinal cells, suggesting virulence properties are compromised by the inactivation of mprF.

CONCLUSIONS: Biofilm formation and gallidermin resistance of L. monocytogenes is influenced by mprF, but this trait is associated with a compromise in invasiveness.

The presence of pathogenic microorganisms in the food processing environment can cause a significant problem, especially when these microorganisms are established as biofilms. This study shows that the inactivation of the mprF gene results in enhanced biofilm formation and abiotic surface attachment of L. monocytogenes.}, } @article {pmid32686304, year = {2020}, author = {Kanampalliwar, A and Singh, DV}, title = {Extracellular DNA builds and interacts with vibrio polysaccharide in the biofilm matrix formed by Vibrio cholerae.}, journal = {Environmental microbiology reports}, volume = {12}, number = {5}, pages = {594-606}, doi = {10.1111/1758-2229.12870}, pmid = {32686304}, issn = {1758-2229}, support = {//Department of Biotechnology, New Delhi/International ; }, mesh = {*Biofilms ; DNA, Bacterial/genetics/*metabolism ; Extracellular Space/genetics/*metabolism ; Polysaccharides, Bacterial/*metabolism ; Vibrio cholerae/genetics/*physiology ; }, abstract = {Vibrio cholerae form biofilm, which is essential for their survival under harsh environmental conditions. The eDNA produced during biofilm formation and interaction with other components like vibrio polysaccharide is less studied in Vibrio cholerae despite its importance in biofilm structure and stability. In this study, we selected two strains of V. cholerae, which produced sufficient extracellular DNA in the biofilm, for characterization and studied its interaction with vibrio polysaccharide. Our data demonstrate that eDNA is present in the biofilm and interacts with VPS in V. cholerae. Our findings suggest that eDNA contributes to biofilm integrity by interacting with VPS and provides strength to the biofilm. Moreover, it might interact with other components of biofilm, which need further study.}, } @article {pmid32685674, year = {2020}, author = {Clitherow, KH and Binaljadm, TM and Hansen, J and Spain, SG and Hatton, PV and Murdoch, C}, title = {Medium-Chain Fatty Acids Released from Polymeric Electrospun Patches Inhibit Candida albicans Growth and Reduce the Biofilm Viability.}, journal = {ACS biomaterials science & engineering}, volume = {6}, number = {7}, pages = {4087-4095}, pmid = {32685674}, issn = {2373-9878}, mesh = {Antifungal Agents/pharmacology ; Biofilms ; *Candida albicans ; *Candidiasis, Oral/drug therapy ; Fatty Acids ; Humans ; }, abstract = {Oral candidiasis is a very common oral condition among susceptible individuals, with the main causative organism being the fungus Candida albicans. Current drug delivery systems to the oral mucosa are often ineffective because of short drug/tissue contact times as well as increased prevalence of drug-resistant Candida strains. We evaluated the potency of saturated fatty acids as antifungal agents and investigated their delivery by novel electrospun mucoadhesive oral patches using agar disk diffusion and biofilm assays. Octanoic (C8) and nonanoic (C9) acids were the most effective at inhibiting C. albicans growth on disk diffusion assays, both in solution or when released from polycaprolactone (PCL) or polyvinylpyrrolidone/RS100 (PVP/RS100) electrospun patches. In contrast, dodecanoic acid (C12) displayed the most potent antifungal activity against pre-existing C. albicans biofilms in solution or when released by PCL or PVP/RS100 patches. Both free and patch-released saturated fatty acids displayed a significant toxicity to wild-type and azole-resistant strains of C. albicans. These data not only provide evidence that certain saturated fatty acids have the potential to be used as antifungal agents but also demonstrate that this therapy could be delivered directly to Candida-infected sites using electrospun mucoadhesive patches, demonstrating a potential new therapeutic approach to treat oral thrush.}, } @article {pmid32683796, year = {2021}, author = {Rouabhia, M and Semlali, A}, title = {Electronic cigarette vapor increases Streptococcus mutans growth, adhesion, biofilm formation, and expression of the biofilm-associated genes.}, journal = {Oral diseases}, volume = {27}, number = {3}, pages = {639-647}, doi = {10.1111/odi.13564}, pmid = {32683796}, issn = {1601-0825}, support = {FO123458//Fondation de l'Université Laval/ ; RGPIN-2019-04475//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Biofilms ; *Dental Caries ; *E-Cigarette Vapor ; *Electronic Nicotine Delivery Systems ; Humans ; Streptococcus mutans/genetics ; }, abstract = {OBJECTIVE: It still not known whether electronic cigarettes (e-cigarettes) contribute to dental caries. This study aimed to evaluate the effect of e-cigarettes on the growth of Streptococcus mutans, the formation of biofilm, and the expression of certain virulence genes.

MATERIALS AND METHODS: Streptococcus mutans cells were exposed or not to e-cigarettes with and without nicotine or to cigarette smoke twice a day for 15 min each exposure period. The bacterial growth and the expression of glucosyltranferase, competence, and glucan-binding genes were evaluated after 24 hr. Biofilm formation was assessed after 1, 2, and 3 days. S. mutans adhesion and growth to e-cigarette exposed human teeth were assessed.

RESULTS: We observed an increase in S. mutans growth with e-cigarettes, mainly at the early culture period. This was confirmed by an increase of biofilm mass ranging from 8 ± 0.5 mg with the control to 47 ± 5 mg after six exposures to nicotine-rich e-cigarettes. S. mutans cells adhered better to e-cigarette exposed teeth. E-cigarettes increased the expression of glucosyltranferase, competence, and glucan-binding genes.

CONCLUSIONS: E-cigarettes increased the growth of S. mutans and the expression of virulent genes. E-cigarettes promoted the adhesion to, and formation of biofilms on teeth surfaces.}, } @article {pmid32683348, year = {2020}, author = {Miari, M and Rasheed, SS and Haidar Ahmad, N and Itani, D and Abou Fayad, A and Matar, GM}, title = {Natural products and polysorbates: Potential Inhibitors of biofilm formation in Pseudomonas aeruginosa.}, journal = {Journal of infection in developing countries}, volume = {14}, number = {6}, pages = {580-588}, doi = {10.3855/jidc.11834}, pmid = {32683348}, issn = {1972-2680}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics ; Biofilms/*drug effects/*growth & development ; Biological Products/*pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Polysorbates/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects/genetics ; }, abstract = {INTRODUCTION: With all the challenges super bugs are imposing, biofilm formation opens the door against various more complicated challenges. Such issue may be highlighted with the ability of the latter to render the antibiotics hardly accessible to bacterial cells and sheds the light on the importance of finding antibiofilm formers. Therefore, we assessed the inhibitory effect of natural product extracts (ginger, wild blueberry) and polysorbates (PS20, PS80) on biofilm formation at the molecular level.

METHODOLOGY: Growth inhibition assay was performed to test the effect of ginger (Zingiber Officinale), wild blueberry (Vaccinium Angustifolium), and polysorbates on Pseudomonas aeruginosa (PAN14) growth. Transcription levels of biofilm exopolysaccharides encoding genes (ndvB, pelC, algC) and quorum sensing genes (lasI, lasR, rhlI, rhlR) for LasI/LasR and RhlI/ RhlR systems were evaluated by RT qPCR.

RESULTS: The polysorbates and the extracts of both ginger and wild blueberry had no effect on the growth of P. aeruginosa. Biofilms' examination has unraveled the effectiveness of treatments used in reducing its formation. Moreover, a significant reduction in the expression of all genes tested for biofilm exopolysaccharides and its quorum sensing system was observed.

CONCLUSION: The decrease in the relative gene expression of the exopolysaccharides and quorum sensing encoding genes sheds the light on the mechanism of action of ginger and wild blueberry's constituents as well as polysorbates 20 and 80 on P. aeruginosa biofilm formation. Future studies need to assess the antibiofilm effect of each fraction of herbal extracts separately.}, } @article {pmid32681872, year = {2020}, author = {Evelhoch, SR}, title = {Biofilm and Chronic Nonhealing Wound Infections.}, journal = {The Surgical clinics of North America}, volume = {100}, number = {4}, pages = {727-732}, doi = {10.1016/j.suc.2020.05.004}, pmid = {32681872}, issn = {1558-3171}, mesh = {*Biofilms ; Chronic Disease ; Humans ; Prosthesis-Related Infections/physiopathology/prevention & control ; Pseudomonas Infections/physiopathology/prevention & control ; Pseudomonas aeruginosa/physiology ; Staphylococcal Infections/physiopathology/prevention & control ; Staphylococcus aureus/physiology ; Therapies, Investigational ; Wound Healing/*physiology ; Wound Infection/diagnosis/*physiopathology/prevention & control ; }, abstract = {In this review, the author summarizes the role of biofilm formation in chronic nonhealing wound infections along with characteristics of biofilm formation, diagnosis, detection, and treatment. Because biofilms are still not clearly understood, treatment and diagnosis are currently difficult.}, } @article {pmid32680859, year = {2020}, author = {Domnin, P and Arkhipova, A and Petrov, S and Sysolyatina, E and Parfenov, V and Karalkin, P and Mukhachev, A and Gusarov, A and Moisenovich, M and Khesuani, Y and Ermolaeva, S}, title = {An In Vitro Model of Nonattached Biofilm-Like Bacterial Aggregates Based on Magnetic Levitation.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {18}, pages = {}, pmid = {32680859}, issn = {1098-5336}, mesh = {*Bacterial Adhesion ; *Biofilms ; Escherichia coli/*physiology ; In Vitro Techniques ; *Magnetic Phenomena ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Models, Biological ; }, abstract = {Chronic infections are associated with the formation of nonattached biofilm-like aggregates. In vitro models of surface-attached biofilms do not always accurately mimic these processes. Here, we tested a new approach to create in vitro nonattached bacterial aggregates using the principle of magnetic levitation of biological objects placed into a magnetic field gradient. Bacteria grown under magnetic levitation conditions formed nonattached aggregates that were studied with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) and characterized quantitatively. Nonattached aggregates consisted of bacteria submerged into an extracellular matrix and demonstrated features characteristic of biofilms, such as a polymeric matrix that binds Ruby Red and Congo red dyes, a prerequisite of bacterial growth, and increased resistance to gentamicin. Three quantitative parameters were explored to characterize strain-specific potential to form nonattached aggregates: geometric sizes, relative quantities of aggregated and free-swimming bacteria, and Congo red binding. Among three tested Escherichia coli strains, one strain formed nonattached aggregates poorly, and for this strain, all three of the considered parameters were different from those of the other two strains (P < 0.05). Further, we characterized biofilm formation on plastic and agar surfaces by these strains and found that good biofilm formation ability does not necessarily indicate good nonattached aggregate formation ability, and vice versa. The model and quantitative methods can be applied for in vitro studies of nonattached aggregates and modeling bacterial behavior in chronic infections, as it is important to increase our understanding of the role that nonattached bacterial aggregates play in the pathogenesis of chronic diseases.IMPORTANCE An increasing amount of evidence indicates that chronic infections are associated with nonattached biofilm-like aggregates formed by pathogenic bacteria. These aggregates differ from biofilms because they form under low-shear conditions within the volume of biological fluids and they do not attach to surfaces. Here, we describe an in vitro model that provides nonattached aggregate formation within the liquid volume due to magnetic levitation. Using this model, we demonstrated that despite morphological and functional similarities of nonattached aggregates and biofilms, strains that exhibit good biofilm formation might exhibit poor nonattached aggregate formation, suggesting that mechanisms underlying the formation of biofilms and nonattached aggregates are not identical. The magnetic levitation approach can be useful for in vitro studies of nonattached aggregate formation and simulation of bacterial behavior in chronic infections.}, } @article {pmid33405678, year = {2019}, author = {Sadrearhami, Z and Namivandi-Zangeneh, R and Price, E and Krasowska, M and Al-Bataineh, SA and Whittle, J and Wong, EHH and Blencowe, A and Boyer, C}, title = {S-Nitrosothiol Plasma-Modified Surfaces for the Prevention of Bacterial Biofilm Formation.}, journal = {ACS biomaterials science & engineering}, volume = {5}, number = {11}, pages = {5881-5887}, doi = {10.1021/acsbiomaterials.9b01063}, pmid = {33405678}, issn = {2373-9878}, abstract = {The development of novel strategies for the prevention of bacterial infections is of utmost importance because of the exponential growth in the number of patient morbidity related to nosocomial and chronic infections. Nitric oxide (NO) is known to be a potent inhibitor of bacterial growth and adhesion to surfaces. Here, we develop an antibiofilm coating that possesses S-nitrosothiol NO donors via plasma polymerization (PP) for biofilm prevention applications. Cell culture dishes of four different film thicknesses ranging from 125 to 1000 nm were coated via PP using a thiol monomer. The thiol functionality on the substrates was converted to S-nitrosothiol NO precursors using tert-butyl nitrite. The successful conjugation of thiol and subsequent formation of S-nitrosothiol functionalities on the substrates were confirmed using X-ray photoelectron spectroscopy and UV-vis analysis. These coatings are capable of releasing NO over 2 days, and the NO loading is tunable by the polymer film thickness. The antibiofilm activity of the surfaces was assessed using Gram-negative bacteria, Pseudomonas aeruginosa. Higher film thickness (and hence, higher NO loading) demonstrate better antibiofilm activity, and the best performing coating shows 81 and 60% inhibition of bacterial attachment to the surface after exposure to bacterial culture solution for 24 and 36 h, respectively. Overall, the NO-releasing plasma-modified surfaces present a potential viable strategy to inhibit bacterial biofilm formation.}, } @article {pmid33405531, year = {2019}, author = {Wang, W and Cheng, X and Liao, J and Lin, Z and Chen, L and Liu, D and Zhang, T and Li, L and Lu, Y and Xia, H}, title = {Synergistic Photothermal and Photodynamic Therapy for Effective Implant-Related Bacterial Infection Elimination and Biofilm Disruption Using Cu9S8 Nanoparticles.}, journal = {ACS biomaterials science & engineering}, volume = {5}, number = {11}, pages = {6243-6253}, doi = {10.1021/acsbiomaterials.9b01280}, pmid = {33405531}, issn = {2373-9878}, abstract = {Implant-related bacterial infections are one of the most common but tricky problems in orthopedic clinics because the formation of biofilms inhibits the penetration of antibiotics to kill bacteria effectively; thus, a new strategy is urgently needed. Antibacterial nanomaterials [e.g., copper (Cu)-based nanoparticles (NPs)] combined with near-infrared (NIR) irradiation show enhanced antibacterial activity against clinical bacteria. However, their antibacterial efficiency toward implant-related infections and against biofilm formation remains unclear. Here, unique polyethylene glycol-modified Cu9S8 NPs with good biocompatibility were synthesized. We found that the Cu9S8 NPs exhibited high photothermal performance and could increase the generation of reactive oxygen species under NIR irradiation (808 nm, 1 W cm[-2]). The Cu9S8 NPs with NIR irradiation successfully destroyed the bacterial structure, resulting in the death of the clinically derived Staphylococcus aureus growing on titanium (Ti) plates. Moreover, this excellent antibacterial activity was indicated to have a synergistic effect with photothermal therapy (PTT) and photodynamic therapy (PDT) by comparison to Cu9S8 with heating treatment in a water bath with similar temperature changes compared to NIR + Cu9S8. Finally, the biofilm formation on the Ti plates was effectively disrupted by NIR + Cu9S8 treatment, while Cu9S8 with thermal treatment showed a mild impact. Hence, Cu9S8 NP-based PTT and PDT can provide a promising approach to eliminating implant-related bacteria and disrupting bacterial biofilms.}, } @article {pmid33405836, year = {2019}, author = {Mutreja, I and Warring, SL and Lim, KS and Swadi, T and Clinch, K and Mason, JM and Sheen, CR and Thompson, DR and Ducati, RG and Chambers, ST and Evans, GB and Gerth, ML and Miller, AG and Woodfield, TBF}, title = {Biofilm Inhibition via Delivery of Novel Methylthioadenosine Nucleosidase Inhibitors from PVA-Tyramine Hydrogels while Supporting Mesenchymal Stromal Cell Viability.}, journal = {ACS biomaterials science & engineering}, volume = {5}, number = {2}, pages = {748-758}, doi = {10.1021/acsbiomaterials.8b01141}, pmid = {33405836}, issn = {2373-9878}, abstract = {The rise of antibiotic resistance, coupled with increased expectations for mobility in later life, is creating a need for biofilm inhibitors and delivery systems that will reduce surgical implant infection. A limitation of some of these existing delivery approaches is toxicity exhibited toward host cells. Here, we report the application of a novel inhibitor of the enzyme, methylthioadenosine nucleosidase (MTAN), a key enzyme in bacterial metabolic pathways, which include S-adenosylmethionine catabolism and purine nucleotide recycling, in combination with a poly(vinyl alcohol)-tyramine-based (PVA-Tyr) hydrogel delivery system. We demonstrate that a lead MTAN inhibitor, selected from a screened library of 34 candidates, (2S)-2-(4-amino-5H-pyrrolo3,2-dpyrimidin-7-ylmethyl)aminoundecan-1-ol (31), showed a minimum biofilm inhibitory concentration of 2.2 ± 0.4 μM against a clinical staphylococcal species isolated from an infected implant. We observed that extracellular DNA, a key constituent of biofilms, is significantly reduced when treated with 10 μM compound 31, along with a decrease in biofilm thickness. Compound 31 was incorporated into a hydrolytically degradable photo-cross-linked PVA-Tyr hydrogel and the release profile was evaluated by HPLC studies. Compound 31 released from the PVA-hydrogel system significantly reduced biofilm formation (77.2 ± 8.4% biofilm inhibition). Finally, compound 31 released from PVA-Tyr showed no negative impact on human bone marrow stromal cell (MSC) viability, proliferation, or morphology. The results demonstrate the potential utility of MTAN inhibitors in treating infections caused by Gram-positive bacteria, and the development of a nontoxic release system that has potential for tunability for time scale of delivery.}, } @article {pmid33350139, year = {2018}, author = {Nahar, S and Mizan, MFR and Ha, AJ and Ha, SD}, title = {Advances and Future Prospects of Enzyme-Based Biofilm Prevention Approaches in the Food Industry.}, journal = {Comprehensive reviews in food science and food safety}, volume = {17}, number = {6}, pages = {1484-1502}, doi = {10.1111/1541-4337.12382}, pmid = {33350139}, issn = {1541-4337}, support = {//Natl. Research Foundation of Korea/ ; 2016R1A2B4007960//Ministry of Education, Science, and Technology/ ; }, abstract = {Food poisoning and foodborne diseases are a growing public health concern worldwide. Approximately 30 known and many unknown pathogens are the main culprits for these conditions. Biofilms are a heterogeneous living-form of pathogens and are considered a safe haven for their pathogenicity. In the field of food processing, the persistence of biofilms results in an increased likelihood of food contamination, which ultimately compromises overall food quality and safety. Because of the robust heterogeneity and resistant phenotypic nature of biofilms, the impairment of biofilms is very challenging when using conventional cleaning agents/antibiotics. Therefore, the development of alternative approaches is of great interest to the food industry. Recently, many researchers have found that use of enzymes can provide an exciting and effective therapeutic approach for solving biofilm-associated problems in the food industry, because enzymes are involved in almost every stage of biofilm detachment and degradation. Here, we describe biofilm-associated problems in the food industry and recent advances in enzyme-based biofilm impairment strategies. We also highlight major limitations, challenges, and possible prospects of enzyme-based biofilm-targeting technologies.}, } @article {pmid32743127, year = {2018}, author = {Manfiolli, AO and Dos Reis, TF and de Assis, LJ and de Castro, PA and Silva, LP and Hori, JI and Walker, LA and Munro, CA and Rajendran, R and Ramage, G and Goldman, GH}, title = {Mitogen activated protein kinases (MAPK) and protein phosphatases are involved in Aspergillus fumigatus adhesion and biofilm formation.}, journal = {Cell surface (Amsterdam, Netherlands)}, volume = {1}, number = {}, pages = {43-56}, pmid = {32743127}, issn = {2468-2330}, support = {MR/N006364/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {The main characteristic of biofilm formation is extracellular matrix (ECM) production. The cells within the biofilm are surrounded by ECM which provides structural integrity and protection. During an infection, this protection is mainly against cells of the immune system and antifungal drugs. A. fumigatus forms biofilms during static growth on a solid substratum and in chronic aspergillosis infections. It is important to understand how, and which, A. fumigatus signal transduction pathways are important for the adhesion and biofilm formation in a host during infection. Here we investigated the role of MAP kinases and protein phosphatases in biofilm formation. The loss of the MAP kinases MpkA, MpkC and SakA had an impact on the cell surface and the ECM during biofilm formation and reduced the adherence of A. fumigatus to polystyrene and fibronectin-coated plates. The phosphatase null mutants ΔsitA and ΔptcB, involved in regulation of MpkA and SakA phosphorylation, influenced cell wall carbohydrate exposure. Moreover, we characterized the A. fumigatus protein phosphatase PphA. The ΔpphA strain was more sensitive to cell wall-damaging agents, had increased β-(1,3)-glucan and reduced chitin, decreased conidia phagocytosis by Dictyostelium discoideum and reduced adhesion and biofilm formation. Finally, ΔpphA strain was avirulent in a murine model of invasive pulmonary aspergillosis and increased the released of tumor necrosis factor alpha (TNF-α) from bone marrow derived macrophages (BMDMs). These results show that MAP kinases and phosphatases play an important role in signaling pathways that regulate the composition of the cell wall, extracellular matrix production as well as adhesion and biofilm formation in A. fumigatus.}, } @article {pmid33429647, year = {2017}, author = {Cox, SC and Jamshidi, P and Eisenstein, NM and Webber, MA and Burton, H and Moakes, RJA and Addison, O and Attallah, M and Shepherd, DET and Grover, LM}, title = {Surface Finish has a Critical Influence on Biofilm Formation and Mammalian Cell Attachment to Additively Manufactured Prosthetics.}, journal = {ACS biomaterials science & engineering}, volume = {3}, number = {8}, pages = {1616-1626}, doi = {10.1021/acsbiomaterials.7b00336}, pmid = {33429647}, issn = {2373-9878}, abstract = {Additive manufacturing (AM) technologies enable greater geometrical design freedom compared with subtractive processes. This flexibility has been used to manufacture patient-matched implants. Although the advantages of AM are clear, the optimization at each process stage is often understated. Here we demonstrate that surface finishing of selective laser melted (SLM) implants significantly alters topography, which has implications for cellular and biofilm adhesion. Hot isostatic pressing of as-fabricated Ti-6Al-4V implants was shown to reduce porosity (1.04 to 0.02%) and surface roughness (34 ± 8 to 22 ± 3 μm). Despite these surface changes, preosteoblasts exhibited a similar viability and proliferation after 7 days of culture. Contrastingly, sandblasting and polishing significantly reduced cellular activity and increased cytotoxicity. Bacterial specimens (Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa) adhered more homogeneously to sandblasted implants compared with other treatments. This suggests that sandblasting may place the implant at risk of infection and reduce the strength of interaction with the surrounding soft tissues. The ability to tune the adhesion of cells to additively manufactured Ti-6Al-4V implants using postprocessing methods was demonstrated. Because the degree of tissue integration required of implants is application specific, these methods may be useful to tailor osseointegration. However, surface competition between mammalian and bacterial cells remains a challenge.}, } @article {pmid32905512, year = {2015}, author = {Hill, C and Pan, M and Babrak, L and Danelishvili, L and Morais, H and Bermudez, LE}, title = {Presence of Virulence-Associated Genes and Ability to Form Biofilm among Clinical Isolates of Escherichia coli Causing Urinary Infection in Domestic Animals.}, journal = {Advances in microbiology}, volume = {5}, number = {8}, pages = {573-579}, pmid = {32905512}, issn = {2165-3402}, support = {R01 AI043199/AI/NIAID NIH HHS/United States ; }, abstract = {BACKGROUND: Urinary tract infection caused by Escherichia coli is a frequently observed condition both in humans and animals. Uropathogenic E. coli (UPEC) has been shown to have a pathogenicity island that enables them to infect the urinary tract. Because there is little information about the presence of UPEC-associated virulent genes in animal isolates this work was carried out with the intent to enhance the understanding about the strains of E.coli that cause infections in animals.

RESULTS: We screened 21 E. coli strains isolated causing urinary tract infection in domestic animals. Primers were designed to amplify urinary infection-associated genes. Nine genes, papA, tcpC, fyuA, tpbA, Lma, hylA, picU, tonB, and flicC were then amplified and sequenced. Different from the human isolate CFT073, all the animals E. coli lack some of the pathogenesis-associated genes. Genes encoding for proteins used to scavenge iron appear not to be so necessary during animal infections as they are in human infection. In further investigation of phenotypic properties, it was observed that animal UPECs have significantly more impaired ability to form biofilms than human UPEC strain.

CONCLUSIONS: This study identified significant differences between human and animal UPECs. This may have its roots in the fact that it is difficult to determine if an animal has symptoms. Future studies will focus on some of the observations.}, } @article {pmid33007795, year = {2013}, author = {Greco-Stewart, VS and Ali, H and Kumaran, D and Kalab, M and Rood, IGH and de Korte, D and Ramírez-Arcos, S}, title = {Biofilm formation by Staphylococcus capitis strains isolated from contaminated platelet concentrates.}, journal = {Journal of medical microbiology}, volume = {62}, number = {12}, pages = {1917}, doi = {10.1099/jmm.0.068593-0}, pmid = {33007795}, issn = {1473-5644}, } @article {pmid33264836, year = {2006}, author = {Gapes, D and Pérez, J and Picioreanu, C and van Loosdrecht, M}, title = {Corrigendum to "Modeling biofilm and floc diffusion processes based on analytical solution of reaction-diffusion equations" [Water Res. 39 (2005) 1311-1323].}, journal = {Water research}, volume = {40}, number = {16}, pages = {3144-3145}, doi = {10.1016/j.watres.2006.06.015}, pmid = {33264836}, issn = {1879-2448}, } @article {pmid32679710, year = {2020}, author = {Achinas, S and Yska, SK and Charalampogiannis, N and Krooneman, J and Euverink, GJW}, title = {A Technological Understanding of Biofilm Detection Techniques: A Review.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {14}, pages = {}, pmid = {32679710}, issn = {1996-1944}, abstract = {Biofouling is a persistent problem in almost any water-based application in several industries. To eradicate biofouling-related problems in bioreactors, the detection of biofilms is necessary. The current literature does not provide clear supportive information on selecting biofilm detection techniques that can be applied to detect biofouling within bioreactors. Therefore, this research aims to review all available biofilm detection techniques and analyze their characteristic properties to provide a comparative assessment that researchers can use to find a suitable biofilm detection technique to investigate their biofilms. In addition, it discusses the confluence of common bioreactor fabrication materials in biofilm formation.}, } @article {pmid32679241, year = {2020}, author = {Balto, H and Bukhary, S and Al-Omran, O and BaHammam, A and Al-Mutairi, B}, title = {Combined Effect of a Mixture of Silver Nanoparticles and Calcium Hydroxide against Enterococcus faecalis Biofilm.}, journal = {Journal of endodontics}, volume = {46}, number = {11}, pages = {1689-1694}, doi = {10.1016/j.joen.2020.07.001}, pmid = {32679241}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Calcium Hydroxide/pharmacology ; Dentin ; *Enterococcus faecalis ; *Metal Nanoparticles ; Root Canal Irrigants ; Silver/pharmacology ; }, abstract = {INTRODUCTION: The aim of this study was to evaluate the antibiofilm effectiveness of calcium hydroxide (Ca[OH]2) mixed with 0.02% silver nanoparticles (AgNPs) in comparison with 1 mg/mL triple antibiotic paste (TAP), Ca(OH)2, and 0.02% AgNPs against Enterococcus faecalis using confocal laser scanning microscopy.

METHODS: Ninety dentin disks were prepared, sterilized, and inoculated with E. faecalis to establish a 3-week-old biofilm model. The samples received 1 mg/mL TAP, a mixture of Ca(OH)2 + 0.02% AgNPs, Ca(OH)2, or 0.02% AgNPs (n = 20/group). Specimens in each group were equally subdivided into 2 groups and incubated for 2 and 4 weeks. Untreated dentin disks (n = 10) were exposed to sterile saline solution and acted as a positive control. Sterile dentin disks (n = 10) were incubated anaerobically in brain-heart infusion broth and served as a negative control. At the end of each observation period, the specimens were stained with LIVE/DEAD BacLight dye (Molecular Probes, Eugene, OR) and analyzed with confocal laser scanning microscopy to determine the proportion of dead cells in the biofilm. Statistical analysis was performed using the generalized linear model repeated measure and Tukey tests (P < .05).

RESULTS: A significantly greater proportion of dead cells was observed in the samples treated with 1 mg/mL TAP (90.39% and 99.41%) and a mixture of Ca(OH)2 + AgNPs (90.85% and 98.49%) than those in the samples treated with Ca(OH)2 (76.14% and 91.71%) and AgNPs (62.83% and 88.07%) at 2 and 4 weeks, respectively. A significant difference in the antibiofilm effectiveness was observed among the groups (P < .05), except for 1 mg/mL TAP and the mixture of Ca(OH)2 + AgNPs (P > .05). All medicaments showed a significant difference in antibiofilm efficacy at the 2 time points.

CONCLUSIONS: The mixture of Ca(OH)2 + AgNPs showed a high antibiofilm effect and was not significantly different from 1 mg/mL TAP. Furthermore, long-term contact between intracanal medicaments and bacterial cells achieved significant antibiofilm efficacy.}, } @article {pmid32679054, year = {2020}, author = {Slettengren, M and Mohanty, S and Kamolvit, W and van der Linden, J and Brauner, A}, title = {Making medical devices safer: impact of plastic and silicone oil on microbial biofilm formation.}, journal = {The Journal of hospital infection}, volume = {106}, number = {1}, pages = {155-162}, doi = {10.1016/j.jhin.2020.07.011}, pmid = {32679054}, issn = {1532-2939}, mesh = {Bacteria/drug effects ; Biofilms/*drug effects ; Candida/drug effects ; Coated Materials, Biocompatible/*pharmacology ; Equipment and Supplies/*microbiology ; Microbial Sensitivity Tests ; Plastics/*pharmacology ; Silicone Oils/*pharmacology ; Viscosity ; }, abstract = {BACKGROUND: Medical devices face the challenge of microbial biofilm attached to the surface. Ultimately, this may jeopardize the function of the device and increase the patient's risk of infection. However, reliable methods to prevent biofilm are lacking.

AIM: To investigate the effect of silicone oil-coated polypropylene plastic, used in a new automatic urinometer, on biofilm formation; furthermore, to explore the impact of silicone oil viscosity and compare polypropylene with polystyrene, another common medical plastic.

METHODS: Common pathogens, including extended-spectrum beta lactamase (ESBL) -producing and multi-drug-resistant bacteria, as well as Candida albicans, were investigated. Isogenic Escherichia coli strains deficient in the important biofilm forming factors curli, cellulose and type 1 fimbriae (fim D) were used to determine the possible mode of action by silicone oil. Clear flat-bottomed polypropylene or polystyrene wells were pretreated with either low- or medium-viscosity silicone oil and microbes were added. After 72 h, biofilm formation was quantified using crystal violet assay.

FINDINGS: Silicone oil-coated polypropylene plastic surfaces, regardless of the oil viscosity, significantly inhibited biofilm formation of all tested Gram-negative and Gram-positive bacteria, including ESBL-producing and multi-drug resistant strains, as well as C. albicans. Silicone oil did not affect bacterial or candida growth and curli fimbriae were found to be the main target of silicone oil. Polypropylene plastic itself without oil had a better effect in preventing biofilm formation than polystyrene.

CONCLUSION: These findings suggest a new strategy to decrease microbial biofilm formation, which may reduce hospital-acquired infections and prevent dysfunction of medical devices.}, } @article {pmid32679053, year = {2020}, author = {Park, KH and Jung, M and Kim, DY and Lee, YM and Lee, MS and Ryu, BH and Hong, SI and Hong, KW and Bae, IG and Cho, OH}, title = {Effects of subinhibitory concentrations of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus.}, journal = {The Journal of hospital infection}, volume = {106}, number = {2}, pages = {295-302}, doi = {10.1016/j.jhin.2020.07.010}, pmid = {32679053}, issn = {1532-2939}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Carrier State/microbiology ; Chlorhexidine/*pharmacology ; Disinfectants/*pharmacology ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Mupirocin/*pharmacology ; Republic of Korea ; Staphylococcal Infections/blood/microbiology ; Tertiary Care Centers ; }, abstract = {BACKGROUND: The effects of subinhibitory concentrations (sub-MICs) of antibacterial agents on the biofilm-forming ability of Staphylococcus aureus require further study.

AIM: To investigate the effects of sub-MICs of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus (MRSA) isolates.

METHODS: MRSA isolates were collected from patients with bloodstream infections at a tertiary care hospital. The basal level of biofilm formation and biofilm induction by sub-MICs of chlorhexidine and mupirocin were evaluated by measuring biofilm mass stained with Crystal Violet.

FINDINGS: Of the 112 MRSA isolates tested, 63 (56.3%) and 44 (39.3%) belonged to sequence type (ST)5 and ST72 lineages, respectively, which are the predominant healthcare- and community-associated clones in South Korea. ST5 isolates were more likely to have chlorhexidine MIC ≥4 (73.0% vs 29.5%), resistance to mupirocin (23.8% vs 0%), agr dysfunction (73.0% vs 9.1%), and qacA/B gene (58.7% vs 2.3%) compared to ST72 isolates. The basal level of biofilm formation ability was frequently stronger in ST72 isolates compared to ST5 isolates (77.3% vs 12.7%). Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in 56.3% and 53.6%, respectively, of all isolates. Biofilm induction was more prevalent in ST5 isolates (85.7% for chlorhexidine, 69.8% for mupirocin) than in ST72 isolates (15.9% for chlorhexidine, 27.3% for mupirocin).

CONCLUSION: Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in half of the clinical MRSA isolates. Our results suggest that ST5 MRSA biofilm can be induced together with some other bacterial virulent factors following exposure to chlorhexidine, which might confer a survival advantage to this clone in the healthcare environment.}, } @article {pmid32674601, year = {2020}, author = {Gonçalves, B and Fernandes, L and Henriques, M and Silva, S}, title = {Environmental pH modulates biofilm formation and matrix composition in Candida albicans and Candida glabrata.}, journal = {Biofouling}, volume = {36}, number = {5}, pages = {621-630}, doi = {10.1080/08927014.2020.1793963}, pmid = {32674601}, issn = {1029-2454}, mesh = {*Biofilms ; Candida ; *Candida albicans ; *Candida glabrata ; Female ; Humans ; Hydrogen-Ion Concentration ; }, abstract = {Candida species are fungal opportunistic pathogens capable of colonizing and infecting various human anatomical sites, where they have to adapt to distinct niche-specific pH conditions. The aim of this study was to analyse the features of Candida albicans and Candida glabrata biofilms developed under neutral and vaginal acidic (pH 4) conditions. C. albicans produced thicker and more filamentous biofilms under neutral than under acidic conditions. On the other hand, the formation of biofilms by C. glabrata was potentiated by the acidic conditions suggesting the high adaptability of this species to the vaginal environment. In general, both species developed biofilms containing higher amounts of matrix components (protein and carbohydrate) under neutral than acidic conditions, although the opposite result was found for one C. glabrata strain. Overall, this study contributes to a better understanding of the modulation of C. albicans and C. glabrata virulence by specific pH conditions.}, } @article {pmid32673893, year = {2020}, author = {van der Kooij, D and Veenendaal, HR and Italiaander, R}, title = {Corroding copper and steel exposed to intermittently flowing tap water promote biofilm formation and growth of Legionella pneumophila.}, journal = {Water research}, volume = {183}, number = {}, pages = {115951}, doi = {10.1016/j.watres.2020.115951}, pmid = {32673893}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; Copper ; Ferric Compounds ; *Legionella pneumophila ; Steel ; Water Microbiology ; Water Supply ; }, abstract = {The information about the impact of copper pipes on the growth of Legionella pneumophila in premise plumbing is controversial. For this reason, pipe segments of copper, stainless steel (SS), mild steel (MS), polyethylene, chlorinated polyvinylchloride (CPVC) and glass (controls) were exposed to intermittently flowing (20 min stagnation time) nonchlorinated tap water of 37 °C or 16 °C (ambient temperature) during six months to study the impact of metals on biofilm formation and growth of L. pneumophila. Biofilm concentrations (BfC, measured as ATP) on copper were 3 (at 37 °C) to 6 (at 16 °C) times higher than on SS. The maximum colony counts of L. pneumophila on the materials tested at 37 °C showed a quadratic relationship with the associated BfCs, with highest values on copper and MS. The average Cu concentration on the glass control of copper (glass-copper) was more than two log units lower than the Fe concentration on glass-MS, suggesting that copper released less corrosion by-products than MS. The release of corrosion by-products with attached biomass from MS most likely enhanced biofilm formation on glass-MS. Cloning and 16S RNA gene sequence analysis of the predominating biofilm bacteria revealed that an uncultured Xanthobacteraceae bacterium and Reyranella accounted for 75% of the bacterial community on copper at 37 °C. The nitrite-oxidizing Nitrospira moscoviensis, which can also utilize hydrogen (H2) and formate, accounted for >50% of the bacterial abundance in the biofilms on MS and glass-MS at 37 °C. The predominating presence of the strictly anaerobic non-fermentative Fe(III)-reducing Geobacter and the Fe(II)-oxidizing Gallionella on MS exposed to tap water of 16 °C indicated anoxic niches and the availability of H2, low molecular weight carboxylic acids (LMWCAs) and Fe(II) at the MS surface. LMWCAs likely also promoted bacterial growth on copper, but the release mechanisms from natural organic matter at the surface of corroding metals are unclear. The effects of water stagnation time and flow dynamics on biofilm formation on copper requires further investigation.}, } @article {pmid32671849, year = {2020}, author = {Manafi, L and Aliakbarlu, J and Dastmalchi Saei, H}, title = {Antibiotic resistance and biofilm formation ability of Salmonella serotypes isolated from beef, mutton, and meat contact surfaces at retail.}, journal = {Journal of food science}, volume = {85}, number = {8}, pages = {2516-2522}, doi = {10.1111/1750-3841.15335}, pmid = {32671849}, issn = {1750-3841}, mesh = {Abattoirs ; Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Cattle ; *Drug Resistance, Multiple, Bacterial ; Food Contamination/analysis ; Humans ; Microbial Sensitivity Tests ; Red Meat/economics/*microbiology ; Salmonella/classification/*drug effects/genetics/*physiology ; Serogroup ; Sheep ; }, abstract = {In this study, Salmonella isolates recovered from meat (beef and mutton) and meat contact surfaces at retail were investigated to determine their serotype, antibiotic resistance, and biofilm formation ability. Salmonella was found in 29 (24.17%) samples out of 120 samples including 14/50 (28%) of beef, 10/40 (25%) of mutton, and 5/30 (16.67%) of meat contact surfaces. Seven isolates were identified as S. Enteritidis, three as S. Typhimurium, and two as S. Typhi, while the rest of the isolates were considered as other Salmonella spp. All of the isolates were resistant to at least one antimicrobial agent and 48.27% of them were identified as multidrug-resistant (MDR) Salmonella. All (100%) of meat contact surfaces isolates, 42.8% of beef isolates, and 30% of mutton isolates were found to be MDR Salmonella. Resistance to nalidixic acid (100%), tetracycline (79.3%), and sulphamethoxazole/trimethoprim (44.8%) were observed. The gyrA gene was detected in 19 of 29 isolates, but tetA was found in one isolate. All of the serotypes were able to form biofilm (75.86 % moderate and 24.14 % strong) and S. Enteritidis was the strongest biofilm producer. The findings indicated that the majority of Salmonella isolates in this study were MDR and biofilm producer. Then, safety measures such as cleaning and disinfection must be taken to control Salmonella and promote public health. PRACTICAL APPLICATION: The present study provides useful information on the prevalence of Salmonella serotypes in meat and meat contact surfaces and their antibiotic resistance patterns as well as biofilm formation capacities. Improving hygiene practices in livestock, slaughterhouses, and at retails may reduce the risk of meat contamination to Salmonella. Meanwhile, high levels of antibiotic resistance in Salmonella isolates emphasized on the improper use of antibiotics.}, } @article {pmid32671613, year = {2020}, author = {García, JFM and Rojas, L and Zenteno, E and Cruz, CV and Abascal, EN}, title = {Characterization of Actinobacillus seminis biofilm formation.}, journal = {Antonie van Leeuwenhoek}, volume = {113}, number = {9}, pages = {1371-1383}, doi = {10.1007/s10482-020-01447-w}, pmid = {32671613}, issn = {1572-9699}, support = {219919//DGAPA-PAPIIT-UNAM/ ; }, mesh = {Actinobacillus Infections/microbiology ; Actinobacillus seminis/*drug effects/*growth & development ; Animals ; Antibodies, Bacterial/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Calcium/*pharmacology ; Furans/pharmacology ; Iron/*pharmacology ; Microbial Viability ; Microscopy, Electron, Scanning ; Quorum Sensing/drug effects ; Sheep ; }, abstract = {Actinobacillus seminis is an autochthonous gram-negative bacterium that affects reproductive organs, causing epididymitis, low fertility, and occasional abortions in ovine and goats. The virulence factors and the pathogenicity mechanisms of A. seminis have not been clearly elucidated yet. In this work, biofilm production by A. seminis in in vitro assays is described and characterized. After 48-h incubation at 37 °C in trypticase soy broth, A. seminis formed biofilms containing an extracellular matrix comprised mainly of fibrillar material. Microaerophilia or the presence of calcium diminished biofilm formation in approximately 50% and 70%, respectively, but low iron concentrations increased it 40%. Through enzymatic digestion, it was found that proteins were the main component of these biofilms. Structural observations through scanning electron microscopy indicated the presence of a high amount of fibrillar material in which bacteria were immersed. Antibodies against different bacterial surface proteins, such as anti-biofilm matrix and anti-adhesin, diminished biofilm formation in 70% and 25%, respectively; whereas furanone C-30 and LED-209, compounds described as quorum-sensing inhibitors, completely inhibited biofilm formation. In conclusion, environmental conditions can influence strongly biofilm formation in A. seminis, and this could be an advantageous strategy that allows bacteria to persist inside a host.}, } @article {pmid32671274, year = {2020}, author = {Gupta, KK and Devi, D}, title = {Characteristics investigation on biofilm formation and biodegradation activities of Pseudomonas aeruginosa strain ISJ14 colonizing low density polyethylene (LDPE) surface.}, journal = {Heliyon}, volume = {6}, number = {7}, pages = {e04398}, pmid = {32671274}, issn = {2405-8440}, abstract = {The accelerated population and industrial development have caused an extensive increase in the use of plastic products. Since polyethylene degrades slowly generating poisonous compounds, therefore, elimination of plastic from the environment is the prerequisite requirement today. Biodegradation of plastics seems to be a convenient and effective method to curb this problem. In view of this, the present study focuses on LDPE degradation capability of bacterial strain Pseudomonas aeruginosa ISJ14 (Accession No. MG554742) isolated from waste dump sites. Further, the stability of 16S rDNA of the isolate was determined by applying bioinformatics tools. For biodegradation studies, the polyethylene films were incubated with the culture of P. aeruginosa ISJ14 in two different growth medium namely Bushnell Hass broth (BHM) and Minimal Salt medium (MSM) for 60 days at 37 °C on 180 rpm. In addition, hydrophobicity and viability of bacterial isolate along with quantification of total protein content was also done. The microbial degradation was confirmed by surface modification and formation of fissures on polyethylene surface along with the variation in the intensity of functional groups as well as an increase in the carbonyl index using field emission scanning electron microscopy (Fe-SEM) and Fourier transform infrared spectrophotometry (FTIR). These results indicate that P. aeruginosa strain ISJ14 can prove to be a suitable candidate for LDPE waste treatment without causing any harm to our health or environment.}, } @article {pmid32671021, year = {2020}, author = {Piarali, S and Marlinghaus, L and Viebahn, R and Lewis, H and Ryadnov, MG and Groll, J and Salber, J and Roy, I}, title = {Activated Polyhydroxyalkanoate Meshes Prevent Bacterial Adhesion and Biofilm Development in Regenerative Medicine Applications.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {442}, pmid = {32671021}, issn = {2296-4185}, abstract = {Regenerative medicine has become an extremely valuable tool offering an alternative to conventional therapies for the repair and regeneration of tissues. The re-establishment of tissue and organ functions can be carried out by tissue engineering strategies or by using medical devices such as implants. However, with any material being implanted inside the human body, one of the conundrums that remains is the ease with which these materials can get contaminated by bacteria. Bacterial adhesion leads to the formation of mature, alive and complex three-dimensional biofilm structures, further infection of surrounding tissues and consequent development of complicated chronic infections. Hence, novel tissue engineering strategies delivering biofilm-targeted therapies, while at the same time allowing tissue formation are highly relevant. In this study our aim was to develop surface modified polyhydroxyalkanoate-based fiber meshes with enhanced bacterial anti-adhesive and juvenile biofilm disrupting properties for tissue regeneration purposes. Using reactive and amphiphilic star-shaped macromolecules as an additive to a polyhydroxyalkanoate spinning solution, a synthetic antimicrobial peptide, Amhelin, with strong bactericidal and anti-biofilm properties, and Dispersin B, an enzyme promoting the disruption of exopolysaccharides found in the biofilm matrix, were covalently conjugated to the fibers by addition to the solution before the spinning process. Staphylococcus epidermidis is one of the most problematic pathogens responsible for tissue-related infections. The initial antibacterial screening showed that Amhelin proved to be strongly bactericidal at 12 μg/ml and caused >50% reductions of biofilm formation at 6 μg/ml, while Dispersin B was found to disperse >70% of pre-formed biofilms at 3 μg/ml. Regarding the cytotoxicity of the agents toward L929 murine fibroblasts, a CC50 of 140 and 115 μg/ml was measured for Amhelin and Dispersin B, respectively. Optimization of the electrospinning process resulted in aligned fibers. Surface activated fibers with Amhelin and Dispersin B resulted in 83% reduction of adhered bacteria on the surface of the fibers. Additionally, the materials developed were found to be cytocompatible toward L929 murine fibroblasts. The strategy reported in this preliminary study suggests an alternative approach to prevent bacterial adhesion and, in turn biofilm formation, in materials used in regenerative medicine applications such as tissue engineering.}, } @article {pmid32670252, year = {2020}, author = {Eix, EF and Nett, JE}, title = {How Biofilm Growth Affects Candida-Host Interactions.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1437}, pmid = {32670252}, issn = {1664-302X}, support = {2017074/DDCF_/Doris Duke Charitable Foundation/United States ; R01 AI145939/AI/NIAID NIH HHS/United States ; }, abstract = {Candida spp. proliferate as surface-associated biofilms in a variety of clinical niches. These biofilms can be extremely difficult to eradicate in healthcare settings. Cells within biofilm communities grow as aggregates and produce a protective extracellular matrix, properties that impact the ability of the host to respond to infection. Cells that disperse from biofilms display a phenotype of enhanced pathogenicity. In this review, we highlight host-biofilm interactions for Candida, focusing on how biofilm formation influences innate immune responses.}, } @article {pmid32670211, year = {2020}, author = {Quintieri, L and Fanelli, F and Zühlke, D and Caputo, L and Logrieco, AF and Albrecht, D and Riedel, K}, title = {Biofilm and Pathogenesis-Related Proteins in the Foodborne P. fluorescens ITEM 17298 With Distinctive Phenotypes During Cold Storage.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {991}, pmid = {32670211}, issn = {1664-302X}, abstract = {In food chain, Pseudomonas spp. cause spoilage by reducing shelf life of fresh products, especially during cold storage, with a high economic burden for industries. However, recent studies have shed new light on health risks occurring when they colonize immunocompromised patient tissues. Likewise to P. aeruginosa, they exhibit antibiotic resistance and biofilm formation, responsible for their spread and persistence in the environment. Biofilm formation might be induced by environmental stresses, such as temperature fluctuations causing physiological and metabolic changes exacerbating food spoilage (by protease and pigment synthesis), and the production of adhesion molecules, chemotactic or underestimated virulence factors. In order to provide a new insight into phenotypic biodiversity of Pseudomonas spoilers isolated from cold stored cheese, in this work 19 Pseudomonas spp. were investigated for biofilm, pigments, exopolysaccharide production and motility at low temperature. Only nine strains showed these phenotypic traits and the blue pigmenting cheese strain P. fluorescens ITEM 17298 was the most distinctive. In addition, this strain decreased the survival probability of infected Galleria mellonella larvae, showing, for the first time, a pathogenic potential. Genomic and proteomic analyses performed on the ITEM 17298 planktonic cells treated or not with lactoferrin derived antibiofilm peptides allowed to reveal specific biofilm related-pathways as well as proteins involved in pathogenesis. Indeed, several genes were found related to signaling system by cGMP-dependent protein kinases, cellulose, rhamnolipid and alginate synthesis, antibiotic resistance, adhesion and virulence factors. The proteome of the untreated ITEM 17298, growing at low temperature, showed that most of the proteins associated with biofilm regulation, pigmentation motility, antibiotic resistance and pathogenecity were repressed, or decreased their levels in comparison to that of the untreated cultures. Thus, the results of this work shed light on the complex pathways network allowing psychrotrophic pseudomonads to adapt themselves to food-refrigerated conditions and enhance their spoilage. In addition, the discovery of virulence factors and antibiotic resistance determinants raises some questions about the need to deeper investigate these underestimated bacteria in order to increase awareness and provide input to update legislation on their detection limits in foods.}, } @article {pmid32669679, year = {2020}, author = {Hofer, U}, title = {How to build a biofilm.}, journal = {Nature reviews. Microbiology}, volume = {18}, number = {9}, pages = {476-477}, pmid = {32669679}, issn = {1740-1534}, mesh = {Bacteria/genetics ; *Biofilms ; *Microscopy ; }, } @article {pmid32669472, year = {2020}, author = {Vandenbussche, I and Sass, A and Pinto-Carbó, M and Mannweiler, O and Eberl, L and Coenye, T}, title = {DNA Methylation Epigenetically Regulates Gene Expression in Burkholderia cenocepacia and Controls Biofilm Formation, Cell Aggregation, and Motility.}, journal = {mSphere}, volume = {5}, number = {4}, pages = {}, pmid = {32669472}, issn = {2379-5042}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Burkholderia cenocepacia/*genetics/*physiology ; *DNA Methylation ; *Epigenesis, Genetic ; *Gene Expression Regulation, Bacterial ; Larva/microbiology ; Methyltransferases/genetics/metabolism ; Moths/microbiology ; Movement ; Virulence ; }, abstract = {Respiratory tract infections by the opportunistic pathogen Burkholderia cenocepacia often lead to severe lung damage in cystic fibrosis (CF) patients. New insights in how to tackle these infections might emerge from the field of epigenetics, as DNA methylation is an important regulator of gene expression. The present study focused on two DNA methyltransferases (MTases) in B. cenocepacia strains J2315 and K56-2 and their role in regulating gene expression. In silico predicted DNA MTase genes BCAL3494 and BCAM0992 were deleted in both strains, and the phenotypes of the resulting deletion mutants were studied: deletion mutant ΔBCAL3494 showed changes in biofilm structure and cell aggregation, while ΔBCAM0992 was less motile. B. cenocepacia wild-type cultures treated with sinefungin, a known DNA MTase inhibitor, exhibited the same phenotype as DNA MTase deletion mutants. Single-molecule real-time sequencing was used to characterize the methylome of B. cenocepacia, including methylation at the origin of replication, and motifs CACAG and GTWWAC were identified as targets of BCAL3494 and BCAM0992, respectively. All genes with methylated motifs in their putative promoter region were identified, and qPCR experiments showed an upregulation of several genes, including biofilm- and motility-related genes, in MTase deletion mutants with unmethylated motifs, explaining the observed phenotypes in these mutants. In summary, our data confirm that DNA methylation plays an important role in regulating the expression of B. cenocepacia genes involved in biofilm formation, cell aggregation, and motility.IMPORTANCE CF patients diagnosed with Burkholderia cenocepacia infections often experience rapid deterioration of lung function, known as cepacia syndrome. B. cenocepacia has a large multireplicon genome, and much remains to be learned about regulation of gene expression in this organism. From studies in other (model) organisms, it is known that epigenetic changes through DNA methylation play an important role in this regulation. The identification of B. cenocepacia genes of which the expression is regulated by DNA methylation and identification of the regulatory systems involved in this methylation are likely to advance the biological understanding of B. cenocepacia cell adaptation via epigenetic regulation. In time, this might lead to novel approaches to tackle B. cenocepacia infections in CF patients.}, } @article {pmid32667788, year = {2020}, author = {Zhou, L and Jiang, Y and Wan, Y and Liu, X and Zhou, H and Li, W and Li, N and Wang, X}, title = {Electron Flow Shifts from Anode Respiration to Nitrate Reduction During Electroactive Biofilm Thickening.}, journal = {Environmental science & technology}, volume = {54}, number = {15}, pages = {9593-9600}, doi = {10.1021/acs.est.0c01343}, pmid = {32667788}, issn = {1520-5851}, mesh = {Biofilms ; *Denitrification ; Electrodes ; *Electrons ; Nitrates ; Nitrogen ; Oxidation-Reduction ; }, abstract = {As electrons generated through substrate oxidation compete with electrodes, dissimilatory nitrate reduction to ammonium (DNRA), denitrification in bioelectrochemical systems in the presence of nitrate, and nitrate reduction through an electroactive biofilm (EAB) are unpredictable. We find that pathways of nitrate reduction are related to EAB thickness and that 76 ± 2 μm is the critical thickness of a biofilm at which both the inner and outer layers simultaneously include DNRA, leading to a maximum level of DNRA efficiency of 42%. Fractions of electrons flowing during nitrate reduction are relatively stable, but their distributions between DNRA and denitrification vary with biofilm thickness. Electrons prefer denitrification in an EAB that is 66 ± 2 μm, while DNRA reversely surpasses denitrification when the thickness increases in the range of 76 ± 2 to 210 ± 2 μm. Biofilm thickening enhances the DNRA of all biofilms close to solution, where nirK remains constant and nrfA is significantly upregulated. However, nrfA is downregulated in layers close to the electrode when the biofilm is thicker than 76 ± 2 μm. These findings reveal the spatially heterogeneous reduction of nitrate in thick EABs, highlighting the importance of biofilm thickness to the regulation of end products of nitrate reduction.}, } @article {pmid32666947, year = {2020}, author = {Rathnaweera, SS and Rusten, B and Manamperuma, LD and Wang, S and Helland, B}, title = {Innovative, compact and energy-efficient biofilm process for nutrient removal from wastewater.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {9}, pages = {1941-1950}, doi = {10.2166/wst.2020.245}, pmid = {32666947}, issn = {0273-1223}, mesh = {Biofilms ; Bioreactors ; Nitrogen/analysis ; Nutrients ; Sewage ; *Waste Disposal, Fluid ; Wastewater/*analysis ; }, abstract = {Rapid population growth, industrial development and stringent demand for treatment of wastewater require developing and emerging economies to upgrade existing wastewater treatment plants (WWTPs) or planning new WWTPs. In the context of unavailability or unaffordability of land and resources for infrastructure expansion, low cost, small footprint, less energy consumption and product reuse are some of the major factors to be considered when either upgrading or designing new WWTPs in developing and emerging economies. Although the transition from activated sludge to biofilm processes has partly solved these challenges, there are innovations that can make the processes even more compact and more efficient. Newly developed CFIC (continuous flow intermittent cleaning) process is the next generation moving bed biological wastewater treatment system and is an example for addressing these issues. The CFIC pilot studies showed promising performance for biological chemical oxygen demand and nitrogen removal as well as particle separation facilitating wastewater reuse.}, } @article {pmid32666184, year = {2020}, author = {Liang, C and Ding, S and Sun, W and Liu, L and Zhao, W and Zhang, D and Ying, H and Liu, D and Chen, Y}, title = {Biofilm-based fermentation: a novel immobilisation strategy for Saccharomyces cerevisiae cell cycle progression during ethanol production.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {17}, pages = {7495-7505}, doi = {10.1007/s00253-020-10770-1}, pmid = {32666184}, issn = {1432-0614}, support = {21636003//National Natural Science Foundation of China/ ; SBK2017010373//National Outstanding Youth Foundation of China/ ; 2018YFA0902200, 2018yfb1501705//National Key Research and Development Program of China/ ; IRT_14R28//the program for changjiang scholars and innovative research team in university/ ; SICAM//Jiangsu National Synergistic Innovation Center for Advanced Materials/ ; BE2014715//Science and Technology Support Program of Jiangsu Province/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; }, mesh = {Biofilms ; Cell Division ; Ethanol ; Fermentation ; Protein Kinases/metabolism ; *Saccharomyces cerevisiae/metabolism ; *Saccharomyces cerevisiae Proteins/genetics/metabolism ; }, abstract = {Biofilm-based fermentation, as a new immobilisation strategy, is beneficial for industrial fermentation due to its excellent environmental resistance, high productivity and continuous fermentation relative to calcium alginate-immobilised fermentation. These two techniques differ mainly regarding cell stages. Here, we describe the cell phenotype of Saccharomyces cerevisiae biofilm-based fermentation and compare cell cycle stages with those during immobilisation in calcium alginate. Most cells in the biofilm-based fermentation adhered to the cotton-fibre carrier of the biofilm and were in the G2/M phase whereas alginate-embedded cells were in the G1/G0 phase. Deletion of the RIM15 gene, which regulates cell cycle progression according to nutritional status, hampered the cell cycle arrest observed in alginate-embedded cells, enhanced biofilm formation and improved fermentation ability. The improved biofilm formation shown by the rim15△ strain could be attributed to an increase in the expression level of the adhesion protein FLO11 and synthesis of trehalose. These findings suggest that the extracellular environment is mainly responsible for the difference between biofilm-based fermentation and alginate-embedded fermentation, and that RIM15 plays an essential role in cell cycle progression. KEY POINTS: • In the biofilm, S. cerevisiae cell populations were mostly in the G2/M phase while alginate-embedded cells were arrested in the G1/G0 phase. • The RIM15 gene partially influenced the cell cycle progression observed during ethanol fermentation. • Biofilm-based cells were actively adsorbed on the physical carrier. • Biofilm immobilisation could maintain cell division activity explaining its fermentation efficiency.}, } @article {pmid32665665, year = {2020}, author = {Kelly, SM and Lanigan, N and O'Neill, IJ and Bottacini, F and Lugli, GA and Viappiani, A and Turroni, F and Ventura, M and van Sinderen, D}, title = {Bifidobacterial biofilm formation is a multifactorial adaptive phenomenon in response to bile exposure.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {11598}, pmid = {32665665}, issn = {2045-2322}, support = {SFI/12/RC/2273-P1/SFI_/Science Foundation Ireland/Ireland ; }, mesh = {Animals ; Bacterial Proteins/genetics ; Bifidobacterium breve/*genetics/growth & development/metabolism ; Bile/metabolism ; Bile Acids and Salts/*adverse effects ; *Biofilms ; Carbon-Sulfur Lyases/genetics ; Gastrointestinal Microbiome/drug effects/*genetics ; Gastrointestinal Tract/drug effects/microbiology ; Gene Expression Profiling ; Humans ; Mutagenesis, Insertional/genetics ; Mutation/genetics ; Osmotic Pressure/drug effects ; Polysaccharides, Bacterial/pharmacology ; Transcriptome/drug effects/genetics ; }, abstract = {In the current study, we show that biofilm formation by various strains and species belonging to Bifidobacterium, a genus that includes gut commensals with reported health-promoting activities, is induced by high concentrations of bile (0.5% (w/v) or higher) and individual bile salts (20 mM or higher), rather than by acid or osmotic stress. The transcriptomic response of a bifidobacterial prototype Bifidobacterium breve UCC2003 to such high bile concentrations was investigated and a random transposon bank of B. breve UCC2003 was screened for mutants that affect biofilm formation in order to identify genes involved in this adaptive process. Eleven mutants affected in their ability to form a biofilm were identified, while biofilm formation capacity of an insertional mutation in luxS and an exopolysaccharide (EPS) negative B. breve UCC2003 was also studied. Reduced capacity to form biofilm also caused reduced viability when exposed to porcine bile. We propose that bifidobacterial biofilm formation is an adaptive response to high concentrations of bile in order to avoid bactericidal effects of high bile concentrations in the gastrointestinal environment. Biofilm formation appears to be a multi-factorial process involving EPS production, proteins and extracellular DNA release, representing a crucial strategy in response to bile stress in order to enhance fitness in the gut environment.}, } @article {pmid32665400, year = {2020}, author = {Yarawsky, AE and Herr, AB}, title = {The staphylococcal biofilm protein Aap forms a tetrameric species as a necessary intermediate before amyloidogenesis.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {37}, pages = {12840-12850}, pmid = {32665400}, issn = {1083-351X}, support = {R01 GM094363/GM/NIGMS NIH HHS/United States ; U19 AI070235/AI/NIAID NIH HHS/United States ; }, mesh = {*Amyloid/chemistry/metabolism ; *Bacterial Proteins/chemistry/metabolism ; *Biofilms ; *Protein Multimerization ; Repetitive Sequences, Amino Acid ; Staphylococcus epidermidis/chemistry/*physiology ; *Zinc/chemistry/metabolism ; }, abstract = {The accumulation-associated protein (Aap) from Staphylococcus epidermidis is a biofilm-related protein that was found to be a critical factor for infection using a rat catheter model. The B-repeat superdomain of Aap, composed of 5-17 B-repeats, each containing a Zn[2+]-binding G5 and a spacer subdomain, is responsible for Zn[2+]-dependent assembly leading to accumulation of bacteria during biofilm formation. We previously demonstrated that a minimal B-repeat construct (Brpt1.5) forms an antiparallel dimer in the presence of 2-3 Zn[2+] ions. More recently, we have reported the presence of functional amyloid-like fibrils composed of Aap within S. epidermidis biofilms and demonstrated that a biologically relevant construct containing five and a half B-repeats (Brpt5.5) forms amyloid-like fibrils similar to those observed in the biofilm. In this study, we analyze the initial assembly events of the Brpt5.5 construct. Analytical ultracentrifugation was utilized to determine hydrodynamic parameters of reversibly associating species and to perform linked equilibrium studies. Linkage studies indicated a mechanism of Zn[2+]-induced dimerization similar to smaller constructs; however, Brpt5.5 dimers could then undergo further Zn[2+]-induced assembly into a previously uncharacterized tetramer. This led us to search for potential Zn[2+]-binding sites outside of the dimer interface. We developed a Brpt5.5 mutant that was unable to form the tetramer and was concordantly incapable of amyloidogenesis. CD and dynamic light scattering indicate that a conformational transition in the tetramer species is a critical step preceding amyloidogenesis. This mechanistic model for B-repeat assembly and amyloidogenesis provides new avenues for potential therapeutic targeting of staphylococcal biofilms.}, } @article {pmid32664334, year = {2020}, author = {Mangiaterra, G and Cedraro, N and Vaiasicca, S and Citterio, B and Galeazzi, R and Laudadio, E and Mobbili, G and Minnelli, C and Bizzaro, D and Biavasco, F}, title = {Role of Tobramycin in the Induction and Maintenance of Viable but Non-Culturable Pseudomonas aeruginosa in an In Vitro Biofilm Model.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, pmid = {32664334}, issn = {2079-6382}, support = {FFC#13/2017//Fondazione per la Ricerca sulla Fibrosi Cistica/ ; FFC#16/2019//Fondazione per la Ricerca sulla Fibrosi Cistica/ ; PSA 2016//Università Politecnica delle Marche/ ; }, abstract = {The recurrence of Pseudomonas aeruginosa (PA) biofilm infections is a major issue in cystic fibrosis (CF) patients. A pivotal role is played by the presence of antibiotic-unresponsive persisters and/or viable but non-culturable (VBNC) forms, whose development might be favored by subinhibitory antibiotic concentrations. The involvement of tobramycin and ciprofloxacin, widely used to treat CF PA lung infections, in the abundance of VBNC cells was investigated in PA biofilms models. In vitro biofilms of the laboratory strain PAO1-N and the clinical strain C24 were developed and starved by subculture for 170 days in a non-nutrient (NN) broth, unsupplemented or supplemented with one-quarter minimal inhibitory concentration (MIC) of tobramycin or ciprofloxacin. VBNC cells abundance, estimated as the difference between total live (detected by qPCR and flow cytometry) and colony forming unit (CFU) counts, showed a strain- and drug-specific pattern. A greater and earlier abundance of VBNC PAO1-N cells was detected in all conditions. Exposure of the C24 strain to NN and NN + ciprofloxacin induced only a transient VBNC subpopulation, which was more abundant and stable until the end of the experiment in tobramycin-exposed biofilms. The same response to tobramycin was observed in the PAO1-N strain. These findings suggest that low tobramycin concentrations might contribute to PA infection recurrence by favoring the development of VBNC forms.}, } @article {pmid32664205, year = {2020}, author = {Trøstrup, H and Laulund, ASB and Moser, C}, title = {Insights into Host-Pathogen Interactions in Biofilm-Infected Wounds Reveal Possibilities for New Treatment Strategies.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, pmid = {32664205}, issn = {2079-6382}, abstract = {Normal wound healing occurs in three phases-the inflammatory, the proliferative, and the remodeling phase. Chronic wounds are, for unknown reasons, arrested in the inflammatory phase. Bacterial biofilms may cause chronicity by arresting healing in the inflammatory state by mechanisms not fully understood. Pseudomonas aeruginosa, a common wound pathogen with remarkable abilities in avoiding host defense and developing microbial resistance by biofilm formation, is detrimental to wound healing in clinical studies. The host response towards P. aeruginosa biofilm-infection in chronic wounds and impact on wound healing is discussed and compared to our own results in a chronic murine wound model. The impact of P. aeruginosa biofilms can be described by determining alterations in the inflammatory response, growth factor profile, and count of leukocytes in blood. P. aeruginosa biofilms are capable of reducing the host response to the infection, despite a continuously sustained inflammatory reaction and resulting local tissue damage. A recent observation of in vivo synergism between immunomodulatory and antimicrobial S100A8/A9 and ciprofloxacin suggests its possible future therapeutic potential.}, } @article {pmid32663508, year = {2020}, author = {Campbell, M and Cho, CY and Ho, A and Huang, JY and Martin, B and Gilbert, ES}, title = {4-Ethoxybenzoic acid inhibits Staphylococcus aureus biofilm formation and potentiates biofilm sensitivity to vancomycin.}, journal = {International journal of antimicrobial agents}, volume = {56}, number = {3}, pages = {106086}, doi = {10.1016/j.ijantimicag.2020.106086}, pmid = {32663508}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Drug Therapy, Combination ; Gallic Acid/analogs & derivatives/pharmacology ; Humans ; Hydrophobic and Hydrophilic Interactions ; Hydroxybenzoate Ethers/*pharmacology ; Staphylococcus aureus/*drug effects ; Structure-Activity Relationship ; Vancomycin/*pharmacology ; }, abstract = {The adverse health effects of Staphylococcus aureus biofilm infections coupled with an increased global prevalence of antibiotic resistance highlight the need for novel anti-pathogenic, anti-biofilm compounds. The authors recently determined that ethyl-4-ethoxybenzoic acid (EEB) had anti-pathogenic, anti-biofilm activity. Based on this finding, a structure-activity analysis was undertaken to identify more effective compounds. Microtitre crystal violet assays followed by plate counts were conducted to measure the dose-dependent anti-biofilm and antimicrobial activities of 13 phenolic compounds related to EEB. By displaying these characteristics on a two-component plot, 4-ethoxybenzoic acid (4EB) and methyl gallate were identified as two anti-pathogenic, anti-biofilm compounds of interest. To characterize their mechanisms of activity, their effects on cell hydrophobicity, hemolysis activity, membrane integrity, extracellular polymeric substance production and vancomycin sensitivity were examined. Both 4EB and methyl gallate inhibited up to 87% of biofilm formation with minimal impact on the viability of stationary-phase cells or bacterial growth. Combination treatments of 4EB and vancomycin decreased the viability of biofilm-dwelling cells by up to 85% compared with vancomycin alone, indicating a synergistic effect. Methyl gallate did not potentiate vancomycin. 4EB decreased the percentage of hydrophobic cells in culture from 78% to 49%, indicating that 4EB may prevent biofilm formation by altering cell membrane hydrophobicity. These findings suggest that 4EB has potential as an anti-pathogenic, anti-biofilm agent for the prevention of S. aureus biofilms, or as a treatment for established biofilms when combined with antibiotics.}, } @article {pmid32663461, year = {2020}, author = {Karygianni, L and Ren, Z and Koo, H and Thurnheer, T}, title = {Biofilm Matrixome: Extracellular Components in Structured Microbial Communities.}, journal = {Trends in microbiology}, volume = {28}, number = {8}, pages = {668-681}, doi = {10.1016/j.tim.2020.03.016}, pmid = {32663461}, issn = {1878-4380}, mesh = {Bacteria/*metabolism/pathogenicity ; Biofilms/*growth & development ; Cellular Microenvironment/physiology ; Extracellular Matrix/*microbiology ; Extracellular Polymeric Substance Matrix/*microbiology ; Humans ; Microbiota/physiology ; Virulence/physiology ; }, abstract = {Biofilms consist of microbial communities embedded in a 3D extracellular matrix. The matrix is composed of a complex array of extracellular polymeric substances (EPS) that contribute to the unique attributes of biofilm lifestyle and virulence. This ensemble of chemically and functionally diverse biomolecules is termed the 'matrixome'. The composition and mechanisms of EPS matrix formation, and its role in biofilm biology, function, and microenvironment are being revealed. This perspective article highlights recent advances about the multifaceted role of the 'matrixome' in the development, physical-chemical properties, and virulence of biofilms. We emphasize that targeting biofilm-specific conditions such as the matrixome could lead to precise and effective antibiofilm approaches. We also discuss the limited knowledge in the context of polymicrobial biofilms, and the need for more in-depth analyses of the EPS matrix in mixed communities that are associated with many human infectious diseases.}, } @article {pmid32663301, year = {2020}, author = {Kowalska, J and MaĆkiw, E and Stasiak, M and Kucharek, K and Postupolski, J}, title = {Biofilm-Forming Ability of Pathogenic Bacteria Isolated from Retail Food in Poland.}, journal = {Journal of food protection}, volume = {83}, number = {12}, pages = {2032-2040}, doi = {10.4315/JFP-20-135}, pmid = {32663301}, issn = {1944-9097}, mesh = {Bacillus cereus ; *Biofilms ; *Listeria monocytogenes ; Poland ; Staphylococcus aureus ; }, abstract = {ABSTRACT: Biofilms have a significant impact on food safety in the food industry. Many foodborne outbreaks have been associated with pathogenic bacterial strains that can form a biofilm. The present study was conducted under the Official Control and Monitoring Program in Poland to examine the ability of pathogenic bacteria collected from retail food samples to form biofilms. Biofilm formation was assessed by qualitative detection of extracellular polymeric substances on Congo red agar, by adherence to glass with the tube method, by the crystal violet biofilm (CV) assay, and by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. A total of 40 isolates from food samples (10 strains each of Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Bacillus cereus) were examined. The strains were classified as adherent, slightly adherent, or nonadherent; biofilm production was classified as weak (WBP), moderate (MBP), or strong (SBP); and metabolic activity was classified as weak (WMA), moderate (MMA), or high (HMA). The incubation conditions and time influenced the amount of biofilm formed as well as did the growth medium. In the test tubes with Luria-Bertani broth (LBB), 22.5% of the strains were adherent and 77.5% were slightly adherent. Stronger adhesion was obtained in brain heart infusion (BHI) with 2% sucrose; 60% of the isolates were classified as adherent. With the CV assay with LBB, SBP was noted for 7.5% of the strains after 24 h of incubation and for 37.5% of the strains after 48 h. In BHI plus 2% sucrose, SBP was noted for 42.5 and 37.6% of the strains after 24 and 48 h, respectively. With the MTT assay with LBB, HMA was found for 15% of the strains after 24 h of incubation and for 25% of the strains after 48 h. In BHI plus 2% sucrose, 70 and 85% of the incubated strains were classified as HMA after 24 and 48 h, respectively.}, } @article {pmid32663201, year = {2020}, author = {Moazzezy, N and Asadi Karam, MR and Rafati, S and Bouzari, S and Oloomi, M}, title = {Inhibition and eradication activity of truncated α-defensin analogs against multidrug resistant uropathogenic Escherichia coli biofilm.}, journal = {PloS one}, volume = {15}, number = {7}, pages = {e0235892}, pmid = {32663201}, issn = {1932-6203}, mesh = {Amoxicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology/toxicity ; *Biofilms ; Cefixime/pharmacology ; Ciprofloxacin/pharmacology ; Drug Resistance, Bacterial ; Drug Synergism ; Norfloxacin/pharmacology ; Uropathogenic Escherichia coli/*drug effects ; alpha-Defensins/*pharmacology/toxicity ; }, abstract = {Today the development of antibiotic resistance, especially in the treatment of bacterial infections associated with biofilms, has led to increasing the importance of antimicrobial peptides (AMPs). In this work, antimicrobial and synergistic activity of three truncated HNP-1 analogs (2Abz14S29, 2Abz23S29, and HNP1ΔC18A) with β-lactam (amoxicillin and cefixime) and fluoroquinolones (ciprofloxacin and norfloxacin) antibiotics against multidrug-resistant (MDR) uropathogenic E. coli clinical isolates were evaluated. The anti-biofilm potential of peptides at different stages was also investigated. All peptides exhibited additive activity just with β-lactam antibiotics in a checkerboard synergy assay. Inhibition and eradication of MDR uropathogenic E. coli biofilm were shown by all test peptides at different concentrations. Thus, truncated HNP-1 analogs (2Abz14S29, 2Abz23S29, and HNP1ΔC18A) may have the potential for the treatment of urinary tract infections (UTIs) caused by biofilm-forming MDR uropathogenic E. coli.}, } @article {pmid32662782, year = {2020}, author = {Burroughs, L and Ashraf, W and Singh, S and Martinez-Pomares, L and Bayston, R and Hook, AL}, title = {Development of dual anti-biofilm and anti-bacterial medical devices.}, journal = {Biomaterials science}, volume = {8}, number = {14}, pages = {3926-3934}, doi = {10.1039/d0bm00709a}, pmid = {32662782}, issn = {2047-4849}, support = {MR/P001033/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Coated Materials, Biocompatible/pharmacology ; Humans ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {The rising occurrence of antimicrobial resistance demands new strategies for delivering antibiotics to ensure their effective use. In this study, a multi-functional strategy to address medical device associated infections is explored whereby an anti-attachment and an antibacterial mechanism have been combined. Silicone catheters impregnated with multiple antibiotics are coated with polyacrylate coatings previously shown to reduce bacterial attachment and biofilm formation. Antibiotics are delivered through the applied coating and the delivery rate depends on the coating thickness and the calculated log P. Coated devices achieve a zone of inhibition and TK100 to Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus similar to those of uncoated devices, whilst maintaining anti-attachment properties. No adverse immunological responses of the coatings were observed. The multi-functional nature of the device developed in the study represents an important approach to combatting medical device associated infections.}, } @article {pmid32662568, year = {2020}, author = {de Chaves, MA and Ferreira do Amaral, T and Monteiro da Silva Rodrigues Coutinho, N and Fernanda Andrzejewski Kaminski, T and Teixeira, ML and Flavio Souza de Oliveira, L and de Andrade, SF and Fuentefria, AM}, title = {Synergistic association of clioquinol with antifungal drugs against biofilm forms of clinical Fusarium isolates.}, journal = {Mycoses}, volume = {63}, number = {10}, pages = {1069-1082}, doi = {10.1111/myc.13142}, pmid = {32662568}, issn = {1439-0507}, support = {16/2551-0000517-6//Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul/ ; //Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brazil (CAPES)/ ; //National Council for Technological Development (CNPq)/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Ciclopirox/pharmacology ; *Clioquinol/administration & dosage/pharmacology/toxicity ; Drug Combinations ; *Drug Synergism ; Fusariosis/*drug therapy ; Fusarium/drug effects/isolation & purification ; Humans ; Leukocytes/drug effects ; Microbial Sensitivity Tests ; Voriconazole/pharmacology ; }, abstract = {BACKGROUND: The influence of biofilm on the complexity of fungal diseases has been reported in recent years, especially in non-invasive mycoses such as keratitis and onychomycosis. The difficulty in treating cases of fusariosis in the human medical clinic exemplifies this situation, because when Fusarium spp. are present in the form of biofilm, the permeation of antifungal agents is compromised.

OBJECTIVES: This study proposes an association of clioquinol, an inhibitor of fungal cells with antifungal drugs prescribed to combat fusariosis in humans.

METHODS: Susceptibility was assessed by microdilution in broth. Formation of biofilm by staining with violet crystal. Inhibition and removal of biofilm using the MTT colorimetric reagent. Time-kill combination, hypoallergenicity test, cytotoxicity test and toxicity prediction by computer analysis were also performed.

RESULTS: Clioquinol associated with voriconazole and ciclopirox inhibited biofilm formation. Possibly, clioquinol acts in the germination and elongation of hyphae, while voriconazole prevents cell adhesion and ciclopirox the formation of the extracellular polymeric matrix. The CLIO-VRC association reduced the biofilm formation by more than 90%, while the CLIO-CPX association prevented over 95%. None of the association was irritating, and over 90% of the leucocytes remained viable. Computational analysis does not reveal toxicity relevant to CLIO, whereas VRC and CPX showed some risks for systemic use, but suitable for topical formulations.

CONCLUSIONS: The combination of CLIO-VRC or CLIO-CPX proved to be a promising association strategy in the medical clinic, both in combating fungal keratitis and onychomycosis, since they prevent the initial process of establishing an infection, the formation of biofilm.}, } @article {pmid32661313, year = {2020}, author = {Heim, CE and Bosch, ME and Yamada, KJ and Aldrich, AL and Chaudhari, SS and Klinkebiel, D and Gries, CM and Alqarzaee, AA and Li, Y and Thomas, VC and Seto, E and Karpf, AR and Kielian, T}, title = {Lactate production by Staphylococcus aureus biofilm inhibits HDAC11 to reprogramme the host immune response during persistent infection.}, journal = {Nature microbiology}, volume = {5}, number = {10}, pages = {1271-1284}, pmid = {32661313}, issn = {2058-5276}, support = {P30 GM110768/GM/NIGMS NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; R01 AI125588/AI/NIAID NIH HHS/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; P20 GM103427/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Biomarkers ; Biosynthetic Pathways ; Cytokines/metabolism ; Histone Deacetylases/*metabolism ; Host-Pathogen Interactions/*immunology ; Inflammation Mediators/metabolism ; Lactic Acid/*metabolism ; Macrophages/immunology/metabolism ; Myeloid-Derived Suppressor Cells/immunology/metabolism ; Staphylococcal Infections/*immunology/metabolism/*microbiology ; Staphylococcus aureus/*physiology ; }, abstract = {Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI), resulting in considerable disability and prolonged treatment. It is known that host leukocyte IL-10 production is required for S. aureus biofilm persistence in PJI. An S. aureus bursa aurealis Tn library consisting of 1,952 non-essential genes was screened for mutants that failed to induce IL-10 in myeloid-derived suppressor cells (MDSCs), which identified a critical role for bacterial lactic acid biosynthesis. We generated an S. aureus ddh/ldh1/ldh2 triple Tn mutant that cannot produce D- or L-lactate. Co-culture of MDSCs or macrophages with ddh/ldh1/ldh2 mutant biofilm produced substantially less IL-10 compared with wild-type S. aureus, which was also observed in a mouse model of PJI and led to reduced biofilm burden. Using MDSCs recovered from the mouse PJI model and in vitro leukocyte-biofilm co-cultures, we show that bacterial-derived lactate inhibits histone deacetylase 11, causing unchecked HDAC6 activity and increased histone 3 acetylation at the Il-10 promoter, resulting in enhanced Il-10 transcription in MDSCs and macrophages. Finally, we show that synovial fluid of patients with PJI contains elevated amounts of D-lactate and IL-10 compared with control subjects, and bacterial lactate increases IL-10 production by human monocyte-derived macrophages.}, } @article {pmid32661124, year = {2020}, author = {Alamiri, F and Chao, Y and Baumgarten, M and Riesbeck, K and Hakansson, AP}, title = {A Role of Epithelial Cells and Virulence Factors in Biofilm Formation by Streptococcus pyogenes In Vitro.}, journal = {Infection and immunity}, volume = {88}, number = {10}, pages = {}, pmid = {32661124}, issn = {1098-5522}, mesh = {Anti-Bacterial Agents/pharmacology ; Antigens, Bacterial/genetics/metabolism ; Bacterial Capsules/genetics/metabolism ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Biomass ; Carrier Proteins/genetics/metabolism ; Drug Resistance, Bacterial ; Epithelial Cells/*microbiology/ultrastructure ; Extracellular Matrix/microbiology/ultrastructure ; Keratinocytes/microbiology/ultrastructure ; Serogroup ; Streptococcus pyogenes/*pathogenicity ; Virulence Factors/genetics/*metabolism ; }, abstract = {Biofilm formation by Streptococcus pyogenes (group A streptococcus [GAS]) in model systems mimicking the respiratory tract is poorly documented. Most studies have been conducted on abiotic surfaces, which poorly represent human tissues. We have previously shown that GAS forms mature and antibiotic-resistant biofilms on physiologically relevant epithelial cells. However, the roles of the substratum, extracellular matrix (ECM) components, and GAS virulence factors in biofilm formation and structure are unclear. In this study, biofilm formation was measured on respiratory epithelial cells and keratinocytes by determining biomass and antibiotic resistance, and biofilm morphology was visualized using scanning electron microscopy. All GAS isolates tested formed biofilms that had similar, albeit not identical, biomass and antibiotic resistance for both cell types. Interestingly, functionally mature biofilms formed more rapidly on keratinocytes but were structurally denser and coated with more ECM on respiratory epithelial cells. The ECM was crucial for biofilm integrity, as protein- and DNA-degrading enzymes induced bacterial release from biofilms. Abiotic surfaces supported biofilm formation, but these biofilms were structurally less dense and organized. No major role for M protein, capsule, or streptolysin O was observed in biofilm formation on epithelial cells, although some morphological differences were detected. NAD-glycohydrolase was required for optimal biofilm formation, whereas streptolysin S and cysteine protease SpeB impaired this process. Finally, no correlation was found between cell adherence or autoaggregation and GAS biofilm formation. Combined, these results provide a better understanding of the role of biofilm formation in GAS pathogenesis and can potentially provide novel targets for future treatments against GAS infections.}, } @article {pmid32661078, year = {2020}, author = {Reichhardt, C and Jacobs, HM and Matwichuk, M and Wong, C and Wozniak, DJ and Parsek, MR}, title = {The Versatile Pseudomonas aeruginosa Biofilm Matrix Protein CdrA Promotes Aggregation through Different Extracellular Exopolysaccharide Interactions.}, journal = {Journal of bacteriology}, volume = {202}, number = {19}, pages = {}, pmid = {32661078}, issn = {1098-5530}, support = {R00 GM134121/GM/NIGMS NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; K99 GM134121/GM/NIGMS NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI061396/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*genetics/*metabolism ; Alginates/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/growth & development ; Extracellular Polymeric Substance Matrix/*metabolism ; Gene Expression Regulation, Bacterial ; Mutation ; Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*genetics/*metabolism ; }, abstract = {Pseudomonas aeruginosa is an important pathogen that causes chronic infections that involve multicellular aggregates called biofilms. Within biofilms, bacteria are surrounded in a protective extracellular matrix of proteins, exopolysaccharides (EPS), and DNA. A key P. aeruginosa matrix protein is an extracellular adhesin called CdrA, which promotes aggregation by binding to the EPS Psl and via CdrA-CdrA interactions. We hypothesized that because of its ability to bind Psl, CdrA would be important only for strains that use Psl as the primary EPS (e.g., the laboratory strain PAO1). Thus, we predicted that cdrA might be dispensable for biofilm formation by strains that do not utilize Psl (e.g., the laboratory strain PA14). Instead, we observed that cdrA deletion strains exhibited biofilm defects, regardless of their EPS dependencies. We screened a panel of clinical and environmental P. aeruginosa isolates for the presence of the cdrA allele and production of CdrA protein. All isolates that we tested contained the cdrA allele, and these alleles had minimal sequence variation compared to the reference PAO1 cdrA gene. Additionally, all isolates except one produced detectable CdrA protein. We investigated the possible mechanisms of CdrA-promoted biofilm formation in these strains where Psl is not dominant, and we discovered that CdrA binds to Pel. Although Psl and Pel chemical structures are distinct, this appears to be a specific interaction, since previous work has shown that CdrA binds discriminately to other EPS. Our findings provide new understanding of biofilm formation across P. aeruginosa isolates and emphasize the versatility of CdrA.IMPORTANCE Depending upon the strain, Pseudomonas aeruginosa can use different exopolysaccharides (e.g., Psl, Pel, and alginate) to build its biofilm matrix. Previously, we demonstrated that the biofilm matrix protein CdrA binds to Psl, promoting biofilm formation and aggregate stability. As such, it was thought that CdrA might be important for biofilm assembly only in strains that rely upon Psl. However, past studies indicated that CdrA can interact with monosaccharides not present in Psl, including N-acetylglucosamine, a constituent of another EPS called Pel. We discovered that CdrA also binds to Pel and promotes biofilm formation by strains in which Psl is not dominant. Thus, our findings suggest that CdrA plays a common role as a biofilm matrix cross-linker across P. aeruginosa isolates with different EPS.}, } @article {pmid32661076, year = {2020}, author = {Hsieh, ML and Waters, CM and Hinton, DM}, title = {VpsR Directly Activates Transcription of Multiple Biofilm Genes in Vibrio cholerae.}, journal = {Journal of bacteriology}, volume = {202}, number = {18}, pages = {}, pmid = {32661076}, issn = {1098-5530}, support = {F30 GM123632/GM/NIGMS NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cyclic GMP/*metabolism ; DNA-Directed RNA Polymerases/*metabolism ; Gene Expression Regulation, Bacterial ; Operon ; Promoter Regions, Genetic ; Sigma Factor/*metabolism ; Vibrio cholerae/*genetics ; }, abstract = {Vibrio cholerae biofilm biogenesis, which is important for survival, dissemination, and persistence, requires multiple genes in the Vibrio polysaccharides (vps) operons I and II as well as the cluster of ribomatrix (rbm) genes. Transcriptional control of these genes is a complex process that requires several activators/repressors and the ubiquitous signaling molecule, cyclic di-GMP (c-di-GMP). Previously, we demonstrated that VpsR directly activates RNA polymerase containing σ[70] (σ[70]-RNAP) at the vpsL promoter (P vpsL), which precedes the vps-II operon, in a c-di-GMP-dependent manner by stimulating formation of the transcriptionally active, open complex. Using in vitro transcription, electrophoretic mobility shift assays, and DNase I footprinting, we show here that VpsR also directly activates σ[70]-RNAP transcription from other promoters within the biofilm formation cluster, including P vpsU , at the beginning of the vps-I operon, P rbmA , at the start of the rbm cluster, and P rbmF , which lies upstream of the divergent rbmF and rbmE genes. In this capacity, we find that VpsR is able to behave both as a class II activator, which functions immediately adjacent/overlapping the core promoter sequence (P vpsL and P vpsU), and as a class I activator, which functions farther upstream (P rbmA and P rbmF). Because these promoters vary in VpsR-DNA binding affinity in the absence and presence of c-di-GMP, we speculate that VpsR's mechanism of activation is dependent on both the concentration of VpsR and the level of c-di-GMP to increase transcription, resulting in finely tuned regulation.IMPORTANCEVibrio cholerae, the bacterial pathogen that is responsible for the disease cholera, uses biofilms to aid in survival, dissemination, and persistence. VpsR, which directly senses the second messenger c-di-GMP, is a major regulator of this process. Together with c-di-GMP, VpsR directly activates transcription by RNA polymerase containing σ[70] from the vpsL biofilm biogenesis promoter. Using biochemical methods, we demonstrate for the first time that VpsR/c-di-GMP directly activates σ[70]-RNA polymerase at the first genes of the vps and ribomatrix operons. In this regard, it functions as either a class I or class II activator. Our results broaden the mechanism of c-di-GMP-dependent transcription activation and the specific role of VpsR in biofilm formation.}, } @article {pmid32660224, year = {2020}, author = {Khasawneh, AI and Himsawi, N and Abu-Raideh, J and Salameh, MA and Al-Tamimi, M and Al Haj Mahmoud, S and Saleh, T}, title = {Status of Biofilm-Forming Genes among Jordanian Nasal Carriers of Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus.}, journal = {Iranian biomedical journal}, volume = {24}, number = {6}, pages = {386-398}, pmid = {32660224}, issn = {2008-823X}, mesh = {Adult ; Aged ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Carrier State/*microbiology ; Female ; *Genes, Bacterial ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Middle Aged ; Nose/*microbiology ; Students, Medical ; }, abstract = {BACKGROUND: Biofilm formation in Staphylococcus aureus is a major virulence factor. Both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are common causes of community- and hospital-acquired infections and are associated with biofilm formation. The status of biofilm-forming genes has not been explored in Jordanian nasal carriers of S. aureus. This study investigates antibiotic resistance patterns and the prevalence of biofilm-forming genes between MSSA and MRSA in two distinct populations in Jordan.

METHODS: A total of 35 MSSA and 22 MRSA isolates were recovered from hospitalized patients and medical students at Prince Hamzah Hospital, Jordan. Antibiotic susceptibility was tested using disk diffusion method and Vitek 2 system. The phenotypic biofilm formation was tested using Congo red agar and microtiter plate assays. The prevalence of the biofilm-forming genes was determined using multiplex PCR.

RESULTS: Among 57 S. aureus isolates, 22 (38.6%) isolates were MRSA and were highly resistant against benzylpenicillin, oxacillin, and imipenem. The frequencies of the icaADBC were 77.1%, 97.1%, 94.3%, and 97.1% respectively in MSSA compared to 86.4%, 100%, 100%, and 100% in MRSA isolates. On the other hand, the frequency of the fnbA, fnbB, clfA, fib, clfB, ebps, eno, and cna genes was 81.8%, 90.9%, 95.5%, 90.9%, 86.4%, 100%, 100%, and 40.9%, respectively in the MRSA isolates.

CONCLUSION: In both groups, MRSA isolates, in comparison to MSSA, were significantly more resistant to cefoxitin, oxacillin, imipenem, tetracycline, clindamycin, and trimethoprim-sulfamethoxazole. Unexpectedly, biofilm formation and gene prevalence between MRSA and MSSA isolates showed no significant difference, suggesting other potential virulence mechanisms.}, } @article {pmid32660074, year = {2020}, author = {Naradasu, D and Miran, W and Okamoto, A}, title = {Metabolic Current Production by an Oral Biofilm Pathogen Corynebacterium matruchotii.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {14}, pages = {}, pmid = {32660074}, issn = {1420-3049}, support = {Grant Nos. 17H04969//Japan Society for the Promotion of Science/ ; 19gm6010002h0004//Japan Agency for Medical Research and Development/ ; }, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Corynebacterium/*physiology ; Electrodes ; }, abstract = {The development of a simple and direct assay for quantifying microbial metabolic activity is important for identifying antibiotic drugs. Current production capabilities of environmental bacteria via the process called extracellular electron transport (EET) from the cell interior to the exterior is well investigated in mineral-reducing bacteria and have been used for various energy and environmental applications. Recently, the capability of human pathogens for producing current has been identified in different human niches, which was suggested to be applicable for drug assessment, because the current production of a few strains correlated with metabolic activity. Herein, we report another strain, a highly abundant pathogen in human oral polymicrobial biofilm, Corynebacterium matruchotii, to have the current production capability associated with its metabolic activity. It showed the current production of 50 nA/cm[2] at OD600 of 0.1 with the working electrode poised at +0.4 V vs. a standard hydrogen electrode in a three-electrode system. The addition of antibiotics that suppress the microbial metabolic activity showed a significant current decrease (>90%), establishing that current production reflected the cellular activity in this pathogen. Further, the metabolic fixation of atomically labeled [13]C (31.68% ± 2.26%) and [15]N (19.69% ± 1.41%) confirmed by high-resolution mass spectrometry indicated that C. matruchotii cells were metabolically active on the electrode surface. The identified electrochemical activity of C. matruchotii shows that this can be a simple and effective test for evaluating the impact of antibacterial compounds, and such a method might be applicable to the polymicrobial oral biofilm on electrode surfaces, given four other oral pathogens have already been shown the current production capability.}, } @article {pmid32660039, year = {2020}, author = {Emett, J and David, R and McDaniel, J and McDaniel, S and Kingsley, K}, title = {Comparison of DNA Extracted from Pediatric Saliva, Gingival Crevicular Fluid and Site-Specific Biofilm Samples.}, journal = {Methods and protocols}, volume = {3}, number = {3}, pages = {}, pmid = {32660039}, issn = {2409-9279}, abstract = {(1) Introduction: Due to the non-invasive nature of saliva, many methods have been used to isolate and collect DNA from saliva samples for microbial screening. Many oral microbes also inhabit the oral biofilm, which may represent significantly different microbial constituents that may contribute to oral health and disease, including caries and periodontal disorders. Moreover, the biofilm may vary within the same patient at different sites. Few studies have evaluated the comparison between DNA isolated from saliva and DNA from site-specific biofilm, with virtually no studies addressing this analysis among pediatric patients. (2) Methods: An existing repository of paper point derived biofilm, gingival crevicular fluid (GCF), and unstimulated saliva samples previously collected from pediatric patients (n = 47) was identified. DNA was isolated from biofilm sites (tongue, upper buccal molar, mandibular lingual incisor), and GCF and saliva were used for quantitative DNA comparison using a phenol:chloroform extraction. A quantitative and qualitative analysis was performed using the NanoDrop 2000 spectrophotometer using absorbance readings at A230 nm, A260 nm and A280 nm. (3) Results: These data demonstrated the successful isolation of DNA from all of the patient samples, with the highest concentrations observed among unstimulated saliva (4264.1 ng/μL) and the lowest derived from GCF (1771.5 ng/μL). No differences were observed between males and females or minorities and non-minority patients. In addition, comparison of the overall concentrations of DNA obtained from adult samples was slightly higher than, but not significantly different from, the concentrations obtained from pediatric samples (p = 0.2827). A real-time quantitative qPCR screening revealed that all of the samples evaluated harbored bacterial and human DNA of sufficient quantity and quality for a molecular screening greater than the limit of detection (ΔRn = 0.01). (4) Conclusions: Many methods are currently available to provide the sampling and screening of saliva and specific sites within the oral cavity, but the validation and comparison of simple and low-cost methods, that include paper point sampling and unstimulated saliva collection, may suggest these methods and protocols provide sufficient DNA quality and quantity for molecular screening and other comparison applications. In addition, although heterogeneity will be a constant and consistent feature between patient samples, standardized methods that provide similar and consistent DNA from various oral sites may provide needed consistency for screening and molecular analysis.}, } @article {pmid32659425, year = {2020}, author = {Xing, Y and Luo, X and Liu, S and Wan, W and Huang, Q and Chen, W}, title = {Synergistic effect of biofilm growth and cadmium adsorption via compositional changes of extracellular matrix in montmorillonite system.}, journal = {Bioresource technology}, volume = {315}, number = {}, pages = {123742}, doi = {10.1016/j.biortech.2020.123742}, pmid = {32659425}, issn = {1873-2976}, mesh = {Adsorption ; Bentonite ; Biofilms ; *Cadmium ; Extracellular Matrix ; Soil ; Soil Pollutants/*analysis ; }, abstract = {The interaction of bacterial biofilm and clay minerals provides great potential for heavy metal remediation in contaminated soil, yet, little is known about how heavy metal, clay minerals and their combinations affect the bacterial biofilm performance and heavy metal adsorption. In this study, the response of biofilm development as well as Cd[2+] adsorption in the presence of Cd[2+] and montmorillonite has been deciphered. Low concentrations of Cd[2+] and montmorillonite or their combinations enhanced biofilm formation by increasing polysaccharides proportion in the biofilm matrix, and the maximum adsorption capacity of Cd[2+] by biofilm was increased by 1.5 times. Furthermore, the immobilization of Cd[2+] by soil was significantly improved when S14-biofilm was introduced. Such results could gain deeper insight into bacterial survival tactics in the complex systems which makes major contribution to microbial remediation of heavy metal polluted environments.}, } @article {pmid32658320, year = {2020}, author = {Li, M and Matouš, K and Nerenberg, R}, title = {Predicting biofilm deformation with a viscoelastic phase-field model: Modeling and experimental studies.}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {11}, pages = {3486-3498}, doi = {10.1002/bit.27491}, pmid = {32658320}, issn = {1097-0290}, mesh = {*Biofilms ; Elasticity/*physiology ; *Models, Biological ; Pseudomonas aeruginosa/cytology/physiology ; *Viscosity ; }, abstract = {Biofilms commonly develop in flowing aqueous environments, where the flow causes the biofilm to deform. Because biofilm deformation affects the flow regime, and because biofilms behave as complex heterogeneous viscoelastic materials, few models are able to predict biofilm deformation. In this study, a phase-field (PF) continuum model coupled with the Oldroyd-B constitutive equation was developed and used to simulate biofilm deformation. The accuracy of the model was evaluated using two types of biofilms: a synthetic biofilm, made from alginate mixed with bacterial cells, and a Pseudomonas aeruginosa biofilm. Shear rheometry was used to experimentally determine the mechanical parameters for each biofilm, used as inputs for the model. Biofilm deformation under fluid flow was monitored experimentally using optical coherence tomography. The comparison between the experimental and modeling geometries, for selected horizontal cross sections, after fluid-driven deformation was good. The relative errors ranged from 3.2 to 21.1% for the synthetic biofilm and from 9.1 to 11.1% for the P. aeruginosa biofilm. This is the first demonstration of the effectiveness of a viscoelastic PF biofilm model. This model provides an important tool for predicting biofilm viscoelastic deformation. It also can benefit the design and control of biofilms in engineering systems.}, } @article {pmid32658271, year = {2020}, author = {Rattanaphan, P and Mittraparp-Arthorn, P and Srinoun, K and Vuddhakul, V and Tansila, N}, title = {Indole signaling decreases biofilm formation and related virulence of Listeria monocytogenes.}, journal = {FEMS microbiology letters}, volume = {367}, number = {14}, pages = {}, doi = {10.1093/femsle/fnaa116}, pmid = {32658271}, issn = {1574-6968}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Humans ; Indoles/*metabolism ; Listeria monocytogenes/genetics/*pathogenicity/*physiology ; Listeriosis/microbiology ; Quorum Sensing ; Virulence ; }, abstract = {Bacterial communication system known as quorum sensing (QS) is a pivotal system for bacterial survival, adaptation and pathogenesis. Members in the multicellular community may synthesize or acquire a signaling molecule in order to elicit downstream cellular processes. Roles of indole and derivatives, a new class of quorum-sensing signal molecules, in various bacterial physiologies and virulence have been reported recently. Indole is normally found in mammal gastrointestinal tract as a metabolite of tryptophan metabolism by microbiota. Therefore, interspecies connection via indole signaling among commensal bacteria and enteric pathogens could be anticipated. Effects of indole exposure on the virulence of Listeria monocytogenes were investigated by phenotypic and molecular approaches. Results demonstrated that synthetic indole and indole-rich conditioned medium significantly diminished biofilm formation and related virulence of L. monocytogenes including motility, cell aggregation and exopolysaccharide production. Transcript levels of virulence-associated (pssE, dltA, flaA, fliI, motB, agrA and hly) and regulatory genes (codY, sigB, prfA and gmaR) were substantially downregulated in indole-treated cells. Only mogR gene encoding for a repressor of motility genes was upregulated after indole exposure. Our findings raise the possibility that L. monocytogenes may acquire indole signaling from gut microbiota for resource-effective adaptation upon transition to new environment.}, } @article {pmid32656058, year = {2020}, author = {Al-Joufi, FA and Aljarallah, KM and Hagras, SA and Al Hosiny, IM and Salem-Bekhit, MM and Youssof, AME and Shakeel, F}, title = {Microbial spectrum, antibiotic susceptibility profile, and biofilm formation of diabetic foot infections (2014-18): a retrospective multicenter analysis.}, journal = {3 Biotech}, volume = {10}, number = {7}, pages = {325}, pmid = {32656058}, issn = {2190-572X}, abstract = {This study identifies the risk factors, microbiological properties, antimicrobial susceptibility patterns, mortality, and clinical complications associated with organisms causing diabetic foot infections (DFIs) with or without antibiotic treatment using data from a retrospective multicenter surveillance. Specimens collected from different hospitals were cultured and the extended-spectrum β-lactamase (ESBL) excretion was estimated. The antibacterial susceptibility pattern and biofilm formation were completed along with the recommended standard methods. Overall, 792 diabetic foot patients (DFPs) were enrolled and a total of 1803 causative organisms were isolated. Polymicrobial infection was identified in 48.5% of the patients. The isolated Gram-positive pathogens (46.7%) were higher than Gram-negative (38.6%) or anaerobes (7.9%). The predominant pathogens were S. aureus (22.2%), methicillin-resistant S. aureus (7.7%), Enterococcus spp. (12.8%), Pseudomonas aeruginosa (9.4%), E. coli (7.9%), Klebsiella spp. (7.5%), Proteus mirabilis (8.9%), coagulase negative staphylococci (CoNS) (6.6%), anaerobic organisms (5.9%), and fungi (2.3%). Vancomycin and clindamycin exhibited no activity against Gram-positive bacteria. However, meropenem and imipenem displayed high activity against the Gram-negative isolates. Out of the 765 tested strains, 251 showed moderate (15.8%) to high (34%) level biofilm-producing phenotype. DFIs were widespread among the diabetic patients with different microbial etiology and the major organisms were aerobic organisms. Our findings may provide an insight into the development of appropriate therapeutic strategies for the management of DFIs.}, } @article {pmid32655644, year = {2020}, author = {Amzil, K and Hamadi, F and Latrache, H and Mimouni, R and Abou Oualid, H and Azelmad, K and Saidi, A and Elboulani, A and Mabrouki, M}, title = {Pseudomonas aeruginosa Biofilm Removal from Two Kinds of Granite Commonly Found in Catering Kitchen.}, journal = {International journal of microbiology}, volume = {2020}, number = {}, pages = {4313908}, pmid = {32655644}, issn = {1687-918X}, abstract = {The biofilm formation on the surfaces which are in direct contact with food products might lead to their contamination and, consequently, present serious health problems for the consumers. The goals of the present work were to study P. aeruginosa biofilm formation on two granites and to investigate the efficiency of sodium hypochlorite (NaCLO) against the same biofilm formed on these substrata using the plate count method (PCM) and epifluorescence microscopy (EP). More biofilm cells adhered to Rosa Porrino than Gris Pinhel, and the PCM method indicated that NaCLO was efficient against the biofilm installed on the Gris Pinhel at the concentration of 1.5% after 15 min of treatment, while it was not efficient against the one installed on the Rosa Porrino. By contrast, the EP showed that the biofilm persists on two granites after NaCLO treatment, at different concentrations and contact times. In addition, the surface properties of granites such as mineral composition, roughness, and physicochemical properties were determined by X-ray diffraction (XRD), scanning electron microscopy coupled with electron diffraction spectroscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared (FTIR), atomic force microscopy (AFM), and contact angle measurement (CAM), respectively. The results revealed that Gris Pinhel is hydrophilic with a high roughness value and Rosa Porrino is hydrophobic with low roughness, while both of them contain the quartz, feldspar, and mica as the main dominant compositions.}, } @article {pmid32655511, year = {2020}, author = {Mohanta, YK and Biswas, K and Jena, SK and Hashem, A and Abd Allah, EF and Mohanta, TK}, title = {Anti-biofilm and Antibacterial Activities of Silver Nanoparticles Synthesized by the Reducing Activity of Phytoconstituents Present in the Indian Medicinal Plants.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1143}, pmid = {32655511}, issn = {1664-302X}, abstract = {Biofilm forming from a variety of microbial pathogens can pose a serious health hazard that is difficult to combat. Nanotechnology, however, represents a new approach to fighting and eradicating biofilm-forming microorganisms. In the present study, the sustainable synthesis and characterization of biocompatible silver nanoparticles (AgNPs) from leaf extracts of Semecarpus anacardium, Glochidion lanceolarium, and Bridelia retusa was explored. Continuous synthesis was observed in a UV-vis spectroscopic analysis and the participating phytoconstituents, flavonoids, phenolic compounds, phytosterols, and glycosides, were characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy. The size and surface charge of the particles were also measured by dynamic light scattering spectroscopy. Scanning electron microscopy study was employed to examine the morphology of the nanoparticles. The spectroscopic and microscopic study confirmed the successful synthesis of AgNPs by plant extracts acting as strong reducing agents. The synthesized AgNPs were screened for antibacterial and anti-biofilm activity against human pathogens Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. Results of the study demonstrate the potential of phyto-synthesized AgNPs to act as anti-biofilm agents and for other biomedical applications.}, } @article {pmid32654773, year = {2020}, author = {Tang, C and Chen, J and Zhang, L and Zhang, R and Zhang, S and Ye, S and Zhao, Z and Yang, D}, title = {Exploring the antibacterial mechanism of essential oils by membrane permeability, apoptosis and biofilm formation combination with proteomics analysis against methicillin-resistant staphylococcus aureus.}, journal = {International journal of medical microbiology : IJMM}, volume = {310}, number = {5}, pages = {151435}, doi = {10.1016/j.ijmm.2020.151435}, pmid = {32654773}, issn = {1618-0607}, mesh = {Amomum/chemistry ; Anti-Infective Agents/chemistry/pharmacology ; Apoptosis/*drug effects ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects ; Biosynthetic Pathways ; Cell Membrane Permeability/*drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*metabolism/ultrastructure ; Microscopy, Electron, Scanning ; Oils, Volatile/chemistry/*pharmacology ; Proteome ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causes of food poisoning and infectious diseases worldwide, it can produce a large number of virulence factors, enhance the colonization ability of the host so that it can quickly colonize and spread on the surface of the objects. Essential oil (EO) is one of the natural products with antimicrobial properties, can be used as an important source of antibacterial agent discovery, and has a broad development prospect. However, the unclear mechanisms of antibacterial action have become an obstacle to its further development and use. Hence, the objective of the present study was to reveal the antibacterial mechanism of EO from Amomum villosum Lour (A villosum Lour) against MRSA using label-free quantitative proteomics, investigate the effect of EO on the bacterial proteome, enzymatic activities and leakage of bacterial intracellular biomacromolecule. Proteomic analysis of MRSA in the presence of EO found that a total of 144 differential expressed proteins (DEPs) between the control and treatment group, in which 42 proteins were distinctly up-regulated and 102 proteins were down-regulated. Besides, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, determination of cell membrane permeability and apoptosis, scanning electron microscopy (SEM) observations, bacterial surface hydrophobicity, and biofilm formation measurement were performed. Collectively, the above results indicated that the cell membrane damage by EO leads to the loss of membrane integrity and causes leakage of intracellular macromolecular substances, inhibition of protein, and biofilm synthesis. These findings manifested that EO exerts antibacterial effect by multiple avenues and expands our understanding of the antibacterial mechanism, it has potential application value in food preservative and pharmaceutical industries.}, } @article {pmid32654599, year = {2020}, author = {Ambrósio, JAR and Pinto, BCDS and da Silva, BGM and Passos, JCDS and Beltrame Junior, M and Costa, MS and Simioni, AR}, title = {BSA nanoparticles loaded-methylene blue for photodynamic antimicrobial chemotherapy (PACT): effect on both growth and biofilm formation by Candida albicans.}, journal = {Journal of biomaterials science. Polymer edition}, volume = {31}, number = {17}, pages = {2182-2198}, doi = {10.1080/09205063.2020.1795461}, pmid = {32654599}, issn = {1568-5624}, mesh = {*Anti-Infective Agents ; Antifungal Agents/pharmacology ; Biofilms ; Candida albicans ; Methylene Blue/pharmacology ; *Nanoparticles ; *Photochemotherapy ; Photosensitizing Agents ; Serum Albumin, Bovine ; }, abstract = {It has been demonstrated an increase in resistance of Candida albicans to conventional therapies, probably, due the indiscriminate use of the conventional antifungal drugs. In this aspect, the nanotechnology generates the possibility of creating new therapeutic agents. Thus, the objective of this paper was to produce and characterize a bovine serum albumin (BSA) nanoparticle encapsulated with Methylene Blue (MB). In addition, the effect of BSA nanoparticles encapsulated with MB (BSA-MB) was evaluated on both growth and biofilm formation by C. albicans by Photodynamic Antimicrobial Chemotherapy (PACT) protocols. The BSA-MB nanoparticles were prepared by the desolvation process. The nanoparticulate system was studied by steady-state techniques, scanning electron microscopy and their biological activity was evaluated in vitro both growth and biofilm formation by C. albicans. The synthetized BSA-MB nanoparticles were spherical in shape exhibiting a 100-200 nm diameter with a low tendency to aggregate (PDI values < 0.2). MB photophysical properties were shown to be preserved after BSA encapsulation. A significant reduction in C. albicans growth, after PACT was observed, in a dependent manner on MB-loaded in BSA nanoparticles concentration used. It was observed an inhibition of 23, 65 and 83% in the presence of MB-loaded in BSA nanoparticles 0.1, 0.5 and 1.0 µg.mL[-1], respectively. In addition, MB-loaded BSA nanoparticles 0.5 µg.mL[-1] were able to reduce both biofilm formation (80%) and the transition from yeast to filamentous form by C. albicans. The results presented here demonstrated a potentiation of the phototoxic effect of MB after BSA encapsulation, since the concentrations of MB-loaded BSA nanoparticles necessary to inhibits ∼50% of C. albicans development was 10 times minor than that observed for free MB. Taken together, these results suggest the potential of PACT, using MB-loaded BSA nanoparticles in inhibiting C. albicans development. The synthesis and design of BSA nanoparticles can be successfully applied for MB encapsulation and offer the possibility to drive the toxicity effect to a specific target, as an evaluation on both growth and biofilm formation by Candida albicans.}, } @article {pmid32654271, year = {2020}, author = {Christensen, DG and Marsden, AE and Hodge-Hanson, K and Essock-Burns, T and Visick, KL}, title = {LapG mediates biofilm dispersal in Vibrio fischeri by controlling maintenance of the VCBS-containing adhesin LapV.}, journal = {Molecular microbiology}, volume = {114}, number = {5}, pages = {742-761}, pmid = {32654271}, issn = {1365-2958}, support = {P20 GM125508/GM/NIGMS NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; R01 GM114288/GM/NIGMS NIH HHS/United States ; R01 GM135254/GM/NIGMS NIH HHS/United States ; R35 GM130355/GM/NIGMS NIH HHS/United States ; R37 AI050661/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*metabolism ; Aliivibrio fischeri/genetics/*metabolism ; Animals ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Decapodiformes/metabolism ; Phosphoric Diester Hydrolases/metabolism ; Signal Transduction ; Symbiosis ; }, abstract = {Efficient symbiotic colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri depends on bacterial biofilm formation on the surface of the squid's light organ. Subsequently, the bacteria disperse from the biofilm via an unknown mechanism and enter through pores to reach the interior colonization sites. Here, we identify a homolog of Pseudomonas fluorescens LapG as a dispersal factor that promotes cleavage of a biofilm-promoting adhesin, LapV. Overproduction of LapG inhibited biofilm formation and, unlike the wild-type parent, a ΔlapG mutant formed biofilms in vitro. Although V. fischeri encodes two putative large adhesins, LapI (near lapG on chromosome II) and LapV (on chromosome I), only the latter contributed to biofilm formation. Consistent with the Pseudomonas Lap system model, our data support a role for the predicted c-di-GMP-binding protein LapD in inhibiting LapG-dependent dispersal. Furthermore, we identified a phosphodiesterase, PdeV, whose loss promotes biofilm formation similar to that of the ΔlapG mutant and dependent on both LapD and LapV. Finally, we found a minor defect for a ΔlapD mutant in initiating squid colonization, indicating a role for the Lap system in a relevant environmental niche. Together, these data reveal new factors and provide important insights into biofilm dispersal by V. fischeri.}, } @article {pmid32654171, year = {2020}, author = {Lucero-Mejía, JE and Romero-Gómez, SJ and Hernández-Iturriaga, M}, title = {A new classification criterion for the biofilm formation index: A study of the biofilm dynamics of pathogenic Vibrio species isolated from seafood and food contact surfaces.}, journal = {Journal of food science}, volume = {85}, number = {8}, pages = {2491-2497}, doi = {10.1111/1750-3841.15325}, pmid = {32654171}, issn = {1750-3841}, mesh = {Animals ; *Biofilms ; Food Contamination/analysis ; Food Microbiology ; Mexico ; Phylogeny ; Seafood/*microbiology ; Vibrio/*classification/genetics/*isolation & purification/physiology ; }, abstract = {The bacterial biofilm formation index (BFI) is measured by a microtiter plate assay, and it is typically performed at 72 hr. However, the dynamics of biopolymer formation change during this incubation period. The aims of this study were to follow the biofilm formation dynamics of Vibrio strains isolated from samples of seafood and food contact surfaces (FCS) and to propose a new BFI classification criterion. Samples from seafood (136) and FCS (14) were collected from retail markets in Queretaro, Mexico. The presence of Vibrio spp. was determined, the strains were isolated, and the six major pathogenic species (V. cholerae, V. alginolyticus, V. fluvialis, V. parahaemolyticus, V. vulnificus, V. mimicus) were identified by PCR. The BFI of the isolates was determined by the microtiter plate method. Fifty-one strains were isolated and identified as V. alginolytivcus (25), V. vulnificus (12), V. cholerae (7), V. parahaemolyticus (6), and V. mimicus (1). A quantitative classification criterion of biofilm formation was proposed based on the following factors: BFI dynamics (no formation, continuous increase, and increase followed by decrease), time of maximum BFI (early: 24 hr; late: 48 to 72 hr), and degree of BFI (none, weak, moderate, and strong). A numerical value was assigned to each factor to correlate the resulting BFI profile with a risk level. Thirteen BFI profiles were observed, having risk level values from 0 to 10. Vibrio alginolyticus, V. cholerae, and V. vulnificus showed the highest BFI profile diversities, which included the riskiest profiles. The proposed BFI criterion describes the dynamics of bacterial biopolymer formation and associates them with the possible risk implications. PRACTICAL APPLICATION: In food processing environments, the presence of bacterial biofilms that could include foodborne pathogens might favor cross-contamination due to direct contact or biofilm dispersal into food products. The new quantitative classification criterion for biofilm formation considers their production dynamics over time, the biofilm quantity, and the level of biofilm dispersal. These characteristics are represented by a numerical value that reflects the level of risk associated with the presence of a biofilm-producing strain on a food contact surface.}, } @article {pmid32654154, year = {2020}, author = {Wu, S and Liu, Y and Lei, L and Zhang, H}, title = {Nanographene oxides carrying antisense walR RNA regulates the Enterococcus faecalis biofilm formation and its susceptibility to chlorhexidine.}, journal = {Letters in applied microbiology}, volume = {71}, number = {5}, pages = {451-458}, doi = {10.1111/lam.13354}, pmid = {32654154}, issn = {1472-765X}, support = {2018SZ0125//Sichuan Provincial Natural Science Foundation of China/ ; 2019YFS0270//Sichuan Provincial Natural Science Foundation of China/ ; 2019YFS0270//Natural Science Foundation of China/ ; 2018SZ0125//Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; Enterococcus faecalis/drug effects/*growth & development ; Graphite/*pharmacology ; Humans ; Microscopy, Confocal ; Oxides/pharmacology ; Periapical Periodontitis/microbiology ; Polyethyleneimine/pharmacology ; RNA, Antisense/*genetics ; Root Canal Irrigants/pharmacology ; }, abstract = {Enterococcus faecalis is the dominant pathogen for persistent periapical periodontitis. The chlorhexidine (CHX) is used as conversional irrigation agents during endodontic root canal therapy. It was reported that the antisense walR RNA (ASwalR) suppressed the biofilm organization. The aim of this study was to investigate the antimicrobial effects of novel graphene oxide (GO)-polyethylenimine (PEI)-based antisense walR (ASwalR) on the inhibition of E. faecalis biofilm and its susceptibility to chlorhexidine. The recombinant ASwalR plasmids were modified with a gene encoding enhanced green fluorescent protein (ASwalR-eGFP) as a reporter gene so that the transformation efficiency could be evaluated by the fluorescence intensity. The GO-PEI-based ASwalR vector transformation strategy was developed to be transformed into E. faecalis and to over-produce ASwalR in biofilms. Colony forming units (CFU) and confocal laser scanning microscopy were used to investigate whether the antibacterial properties of antisense walR interference strategy sensitize E. faecalis biofilm to the CHX. The results indicated that overexpression of ASwalR by GO-PEI-based transformation strategy could inhibit biofilm formation, decrease the EPS synthesis and increase the susceptibility of E. faecalis biofilms to CHX. Our reports demonstrated that antisense walR RNA will be a supplementary strategy in treating E. faecalis with irrigation agents.}, } @article {pmid32652741, year = {2020}, author = {Morghad, T and Hassaine, H and Boutarfi, Z and Gaouar, S and Bellifa, S and Meziani, Z}, title = {Bacteriological water quality and biofilm formation in the treatment system of the hemodialysis unit in Tlemcen, Algeria.}, journal = {Seminars in dialysis}, volume = {33}, number = {5}, pages = {394-401}, doi = {10.1111/sdi.12898}, pmid = {32652741}, issn = {1525-139X}, mesh = {Algeria/epidemiology ; Biofilms ; *Hemodialysis Units, Hospital ; Humans ; Renal Dialysis ; Water Microbiology ; *Water Quality ; }, abstract = {OBJECTIVE: To evaluate and compare the microbiological quality of osmosis water at the distribution loop, at the dialysis generator inlet and to study the prevalence of biofilm in the tubing.

METHODS: Microbiological analysis of 20 water loop samples, 10 water samples were taken at the machine entry and 10 pipe segments from tubing connecting the machines to the loop was done.

RESULTS: The bacterial enumeration results of the loop water vary from 90 to 150 CFU/mL, while the average number of bacteria at the entry of the machines was 182 CFU/mL. The counts of the adhered bacteria in the tubing were worrying with rates ranging from 4.30 to 6.74 Log CFU/ cm[2] . Fifty percentage of the strains isolated were Bacillus, followed by Enterobacter cloacae 23.52%, Staphylococcus, and others such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumanii. More than half of the tubing strains were highly formative of biofilm, 13 strains with medium capacity and 10 were weakly.

CONCLUSION: This study indicates bacterial water contamination. The formation of a biofilm will certainly harm the effectiveness of the various disinfection methods in this unit. Water quality is influenced not only by the high rate of bacterial colonization, but also differences in standards for dialysis water.}, } @article {pmid32652437, year = {2020}, author = {Yu, Z and Pei, H and Li, Y and Yang, Z and Xie, Z and Hou, Q and Nie, C}, title = {Inclined algal biofilm photobioreactor (IABPBR) for cost-effective cultivation of lipid-rich microalgae and treatment of seawater-diluted anaerobically digested effluent from kitchen waste with the aid of phytohormones.}, journal = {Bioresource technology}, volume = {315}, number = {}, pages = {123761}, doi = {10.1016/j.biortech.2020.123761}, pmid = {32652437}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; Cost-Benefit Analysis ; Lipids ; *Microalgae ; *Photobioreactors ; Plant Growth Regulators ; Seawater ; Wastewater ; }, abstract = {Previous study has demonstrated that freshwater can be replaced with seawater for dilution of feed to algal production and wastewater treatment, but high harvest cost in suspended-growth systems is still a troublesome limitation for large-scale production. Therefore, a novel inclined algal biofilm photobioreactor (IABPBR) was constructed for algal bioproduct production and treatment of seawater-diluted anaerobically digested effluent (SA) in this study. Fluffy polyester was selected as the best carrier for the algal biofilm among ten discarded materials. With the help of phytohormones, the viability of SDEC-18 was clearly enhanced and an algal biomass productivity of 5.66 g/m[2]/d was achieved. The SDEC-18 biofilm provided removal capacities of 0.65, 0.25 and 3.31 g/m[2]/d for TN, TP and COD. Phytohormones clearly enhanced the lipid biosynthesis, with an extraordinary lipid productivity of 3.98 g/m[2]/d being achieved. Moreover, an automatic harvesting system was designed for the efficient harvesting process during large-scale production.}, } @article {pmid32651162, year = {2020}, author = {Novotny, LA and Goodman, SD and Bakaletz, LO}, title = {Targeting a bacterial DNABII protein with a chimeric peptide immunogen or humanised monoclonal antibody to prevent or treat recalcitrant biofilm-mediated infections.}, journal = {EBioMedicine}, volume = {59}, number = {}, pages = {102867}, pmid = {32651162}, issn = {2352-3964}, support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antibodies, Monoclonal/immunology/*pharmacology ; Bacterial Infections/drug therapy/microbiology/prevention & control ; Bacterial Proteins/*antagonists & inhibitors/immunology ; Biofilms/*drug effects ; DnaB Helicases/*antagonists & inhibitors/immunology ; Drug Evaluation, Preclinical ; Humans ; Mice ; Peptides/chemistry/immunology/*pharmacology ; Rabbits ; }, abstract = {BACKGROUND: Chronic and recurrent bacterial diseases are recalcitrant to treatment due to the ability of the causative agents to establish biofilms, thus development of means to prevent or resolve these structures are greatly needed. Our approach targets the DNABII family of bacterial DNA-binding proteins, which serve as critical structural components within the extracellular DNA scaffold of biofilms formed by all bacterial species tested to date. DNABII-directed antibodies rapidly disrupt biofilms and release the resident bacteria which promote their subsequent clearance by either host immune effectors or antibiotics that are now effective at a notably reduced concentration.

METHODS: First, as a therapeutic approach, we used intact IgG or Fab fragments against a chimeric peptide immunogen designed to target protective epitopes within the DNA-binding tip domains of integration host factor to disrupt established biofilms in vitro and to mediate resolution of existing disease in vivo. Second, we performed preventative active immunisation with the chimeric peptide to induce the formation of antibody that blocks biofilm formation and disease development in a model of viral-bacterial superinfection. Further, toward the path for clinical use, we humanised a monoclonal antibody against the chimeric peptide immunogen, then characterised and validated that it maintained therapeutic efficacy.

FINDINGS: We demonstrated efficacy of each approach in two well-established pre-clinical models of otitis media induced by the prevalent respiratory tract pathogen nontypeable Haemophilus influenzae, a common biofilm disease.

INTERPRETATION: Collectively, our data revealed two approaches with substantive efficacy and potential for broad application to combat diseases with a biofilm component.

FUNDING: Supported by R01 DC011818 to LOB and SDG.}, } @article {pmid32650496, year = {2020}, author = {Roscetto, E and Masi, M and Esposito, M and Di Lecce, R and Delicato, A and Maddau, L and Calabrò, V and Evidente, A and Catania, MR}, title = {Anti-Biofilm Activity of the Fungal Phytotoxin Sphaeropsidin A Against Clinical Isolates of Antibiotic-Resistant Bacteria.}, journal = {Toxins}, volume = {12}, number = {7}, pages = {}, pmid = {32650496}, issn = {2072-6651}, support = {E62F16001250003//Compagnia di San Paolo/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology/toxicity ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Bridged Bicyclo Compounds, Heterocyclic/*pharmacology ; Cell Line ; Diterpenes/*pharmacology/toxicity ; Dose-Response Relationship, Drug ; *Drug Resistance, Bacterial ; Drug Synergism ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Many pathogens involved in human infection have rapidly increased their antibiotic resistance, reducing the effectiveness of therapies in recent decades. Most of them can form biofilms and effective drugs are not available to treat these formations. Natural products could represent an efficient solution in discovering and developing new drugs to overcome antimicrobial resistance and treat biofilm-related infections. In this study, 20 secondary metabolites produced by pathogenic fungi of forest plants and belonging to diverse classes of naturally occurring compounds were evaluated for the first time against clinical isolates of antibiotic-resistant Gram-negative and Gram-positive bacteria. epi-Epoformin, sphaeropsidone, and sphaeropsidin A showed antimicrobial activity on all test strains. In particular, sphaeropsidin A was effective at low concentrations with Minimum Inhibitory Concentration (MIC) values ranging from 6.25 μg/mL to 12.5 μg/mL against all reference and clinical test strains. Furthermore, sphaeropsidin A at sub-inhibitory concentrations decreased methicillin-resistant S. aureus (MRSA) and P. aeruginosa biofilm formation, as quantified by crystal violet staining. Interestingly, mixtures of sphaeropsidin A and epi-epoformin have shown antimicrobial synergistic effects with a concomitant reduction of cytotoxicity against human immortalized keratinocytes. Our data show that sphaeropsidin A and epi-epoformin possess promising antimicrobial properties.}, } @article {pmid32649279, year = {2020}, author = {Ogasawara, H and Ishizuka, T and Hotta, S and Aoki, M and Shimada, T and Ishihama, A}, title = {Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {9}, pages = {880-890}, doi = {10.1099/mic.0.000947}, pmid = {32649279}, issn = {1465-2080}, mesh = {Binding Sites ; Biofilms/*growth & development ; Escherichia coli K12/*genetics/*growth & development/metabolism ; Escherichia coli Proteins/*genetics/metabolism ; Fimbriae, Bacterial/physiology ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; *Promoter Regions, Genetic ; Trans-Activators/*genetics/metabolism ; Transcription Factors/genetics/*metabolism ; }, abstract = {Under stressful conditions, Escherichia coli forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study 'promoter-specific transcription-factor' (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.}, } @article {pmid32646902, year = {2020}, author = {Cavalcanti, GS and Wasserscheid, J and Dewar, K and Shikuma, NJ}, title = {Complete Genome Sequences of Two Marine Biofilm Isolates, Leisingera sp. nov. Strains 201A and 204H, Novel Representatives of the Roseobacter Group.}, journal = {Microbiology resource announcements}, volume = {9}, number = {28}, pages = {}, pmid = {32646902}, issn = {2576-098X}, abstract = {Here, we report the complete-genome assemblies of biofilm isolates 201A and 204H. They possess six and seven plasmids, respectively, with a size ranging from 44 kb to 159 kb. Genomic comparisons place the two strains into one new species belonging to the genus Leisingera as novel representatives of the Roseobacter group.}, } @article {pmid32644968, year = {2020}, author = {Schraa, O and Rosenthal, A and Wade, MJ and Rieger, L and Miletić, I and Alex, J}, title = {Assessment of aeration control strategies for biofilm-based partial nitritation/anammox systems.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {8}, pages = {1757-1765}, doi = {10.2166/wst.2020.174}, pmid = {32644968}, issn = {0273-1223}, mesh = {Ammonia ; Biofilms ; *Bioreactors ; *Nitrogen ; Oxidation-Reduction ; }, abstract = {The objective of this work was to compare the nitrogen removal in mainstream, biofilm-based partial nitritation anammox (PN/A) systems employing (1) constant setpoint dissolved oxygen (DO) control, (2) intermittent aeration, and (3) ammonia-based aeration control (ABAC). A detailed water resource recovery facility (WRRF) model was used to study the dynamic performance of these aeration control strategies with respect to treatment performance and energy consumption. The results show that constant setpoint DO control cannot meet typical regulatory limits for total ammonia nitrogen (NHx-N). Intermittent aeration shows improvement but requires optimisation of the aeration cycle. ABAC shows the best treatment performance with the advantages of continuous operation and over 20% lower average energy consumption as compared to intermittent aeration.}, } @article {pmid32640544, year = {2020}, author = {Minami, M and Takase, H and Taira, M and Makino, T}, title = {Suppressive Effects of Hainosan (Painongsan) against Biofilm Production by Streptococcus mutans.}, journal = {Dentistry journal}, volume = {8}, number = {3}, pages = {}, pmid = {32640544}, issn = {2304-6767}, abstract = {Streptococcus mutans, a bacterium that causes dental plaques, forms a biofilm on tooth surfaces. This biofilm can cause gingivitis by stimulating the gingival margin. However, there is no established treatment for biofilm removal. Hainosan (Painongsan), a traditional Japanese Kampo formula, has been used to treat gingivitis. Therefore, we investigated the biofilm suppressive effects of the hainosan extract (HNS) and its components on S. mutans. We conducted scanning electron microscopy and confocal laser microscopy analyses to clarify the anti-biofilm activities of HNS and its crude drugs. We also performed a quantitative RT-PCR assay to assess the biofilm-related gene expression. HNS showed a significant dose-dependent suppressive effect on biofilm formation. Both the scanning electron microscopy and confocal laser microscopy analyses also revealed the significant inhibitory effects of the extract on biofilm formation. Transmission electron microscopy analysis showed that HNS disrupted the surface of the bacterial wall. Furthermore, HNS reduced the hydrophobicity of the bacteria, and suppressed the mRNA expression of β-glucosyltransferase (gtfB), glucosyltransferase-SI (gtfC), and fructosyltransferase (ftf). Among the constituents of hainosan, the extract of the root of Platycodon grandiflorum (PG) showed the strongest biofilm suppression effect. Platycodin D, one of the constituent natural compounds of PG, inhibited S. mutans-associated biofilm. These findings indicate that hainosan eliminates dental plaques by suppressing biofilm formation by S. mutans.}, } @article {pmid32640045, year = {2021}, author = {Gonzalez, T and Stevens, ML and Baatyrbek Kyzy, A and Alarcon, R and He, H and Kroner, JW and Spagna, D and Grashel, B and Sidler, E and Martin, LJ and Biagini Myers, JM and Khurana Hershey, GK and Herr, AB}, title = {Biofilm propensity of Staphylococcus aureus skin isolates is associated with increased atopic dermatitis severity and barrier dysfunction in the MPAACH pediatric cohort.}, journal = {Allergy}, volume = {76}, number = {1}, pages = {302-313}, pmid = {32640045}, issn = {1398-9995}, support = {R01 AI127392/AI/NIAID NIH HHS/United States ; T32 GM063483/GM/NIGMS NIH HHS/United States ; U19 AI070235/AI/NIAID NIH HHS/United States ; UL1 TR001425/TR/NCATS NIH HHS/United States ; }, mesh = {Adult ; Biofilms ; Child ; *Dermatitis, Atopic ; Filaggrin Proteins ; Humans ; Skin ; *Staphylococcal Infections ; Staphylococcus aureus ; Staphylococcus epidermidis/genetics ; }, abstract = {BACKGROUND: Atopic dermatitis (AD) patients are often colonized with Staphylococcus aureus, and staphylococcal biofilms have been reported on adult AD skin lesions. The commensal S epidermidis can antagonize S aureus, although its role in AD is unclear. We sought to characterize S aureus and S epidermidis colonization and biofilm propensity and determine their associations with AD severity, barrier function, and epidermal gene expression in the first US early-life cohort of children with AD, the Mechanisms of Progression of Atopic Dermatitis to Asthma in Children (MPAACH).

METHODS: The biofilm propensity of staphylococcal isolates was assessed by crystal violet assays. Gene expression of filaggrin and antimicrobial alarmins S100A8 and S100A9 was measured in keratinocyte RNA extracted from skin tape strips. Staphylococcal biofilms sampled from MPAACH skin were visualized using scanning electron microscopy.

RESULTS: Sixty-two percent of staphylococcal isolates (sampled from 400 subjects) formed moderate/strong biofilms. Sixty-eight percent of subjects co-colonized with both staphylococcal species exhibited strains that formed cooperative mixed-species biofilms. Scanning electron microscopy verified the presence of staphylococcal biofilms on the skin of MPAACH children. Staphylococcus aureus strains showing higher relative biofilm propensity compared with S epidermidis were associated with increased AD severity (P = .03) and increased lesional and nonlesional transepidermal water loss (P = .01, P = .03).

CONCLUSIONS: Our data suggest a pathogenic role for S aureus biofilms in AD. We found that strain-level variation in staphylococcal isolates governs the interactions between S epidermidis and S aureus and that the balance between these two species, and their biofilm propensity, has important implications for AD.}, } @article {pmid32637741, year = {2020}, author = {Han, W and Zhou, B and Yang, K and Xiong, X and Luan, S and Wang, Y and Xu, Z and Lei, P and Luo, Z and Gao, J and Zhan, Y and Chen, G and Liang, L and Wang, R and Li, S and Xu, H}, title = {Biofilm-inspired adhesive and antibacterial hydrogel with tough tissue integration performance for sealing hemostasis and wound healing.}, journal = {Bioactive materials}, volume = {5}, number = {4}, pages = {768-778}, pmid = {32637741}, issn = {2452-199X}, abstract = {Uncontrolled bleeding and infection can cause significant increases in mortalities. Hydrogel sealants have attracted extensive attention for their ability to control bleeding. However, because interfacial water is a formidable barrier to strong surface bonding, a challenge remains in finding a product that offers robust tissue adhesion combined with anti-infection properties. Inspired by the strong adhesive mechanism of biofilm and mussels, we report a novel dual bionic adhesive hydrogel (DBAH) based on chitosan grafted with methacrylate (CS-MA), dopamine (DA), and N-hydroxymethyl acrylamide (NMA) via a facile radical polymerization process. CS-MA and DA were simultaneously included in the adhesive polymer for imitating the two key adhesive components: polysaccharide intercellular adhesin (PIA) of staphylococci biofilm and 3,4-dihydroxy-l-phenylalanine (Dopa) of mussel foot protein, respectively. DBAH presented strong adhesion at 34 kPa even upon three cycles of full immersion in water and was able to withstand up to 168 mm Hg blood pressure, which is significantly higher than the 60-160 mm Hg measured in most clinical settings. Most importantly, these hydrogels presented outstanding hemostatic capability under wet and dynamic in vivo movements while displaying excellent antibacterial properties and biocompatibility. Therefore, DBAH represents a promising class of biomaterials for high-efficiency hemostasis and wound healing.}, } @article {pmid32636429, year = {2020}, author = {Elamary, RB and Albarakaty, FM and Salem, WM}, title = {Efficacy of Acacia nilotica aqueous extract in treating biofilm-forming and multidrug resistant uropathogens isolated from patients with UTI syndrome.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {11125}, pmid = {32636429}, issn = {2045-2322}, mesh = {Acacia/*chemistry ; Acinetobacter Infections/drug therapy ; Acinetobacter baumannii/drug effects ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Child ; Drug Resistance, Multiple, Bacterial ; Escherichia coli Infections/drug therapy ; Female ; Gas Chromatography-Mass Spectrometry ; Humans ; Klebsiella Infections/drug therapy ; Klebsiella pneumoniae/drug effects ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Plant Extracts/*therapeutic use ; Proteus Infections/drug therapy ; Proteus mirabilis/drug effects ; Pseudomonas Infections/drug therapy ; Urinary Tract Infections/*drug therapy/microbiology ; Uropathogenic Escherichia coli/drug effects ; Young Adult ; }, abstract = {Escherichia coli is the dominant bacterial cause of UTI among the uropathogens in both developed and developing countries. This study is to investigate the effect of Acacia nilotica aqueous extract on the survival and biofilm of isolated pathogens to reduce UTIs diseases. A total of 170 urine samples were collected from Luxor general hospital and private medical analysis laboratories in Luxor providence, Egypt. Samples were screened for the incidence of uropathogens by biochemical tests, antibiotics susceptibility, detection of virulence, and antibiotic-resistant genes by multiplex PCR, biofilm formation, and time-killing assay. Escherichia coli is by far the most prevalent causative agent with the percentage of 73.7% followed by Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeuroginosa, and Acinetobacter baumanii. Isolates were multidrug-resistant containing blaTEM, blaSHV, blaCTX, qnrs, and aac(3)-Ia resistant genes. All isolates were sensitive to 15-16.7 mg ml[-1] of Acacia nilotica aqueous extract. Time killing assay confirmed the bactericidal effect of the extract over time (20-24 h). A high percentage of 3-Cyclohexane-1-Carboxaldehyde, 2,6,6-trimethyl (23.5%); á-Selinene (15.12%); Oleic Acid (14.52%); Globulol (11.35%) were detected among 19 bioactive phytochemical compounds in the aqueous extract of A. nilotica over the GC-mass spectra analysis. The plant extract reduced significantly the biofilm activity of E. coli, K. pneumoniae, P. mirabilis, and P. aeuroginosa by 62.6, 59. 03, 48.9 and 39.2%, respectively. The challenge to improve the production of A. nilotica phytochemicals is considered a very low price for the return.}, } @article {pmid32636245, year = {2020}, author = {Freiberg, JA and Le Breton, Y and Harro, JM and Allison, DL and McIver, KS and Shirtliff, ME}, title = {The Arginine Deiminase Pathway Impacts Antibiotic Tolerance during Biofilm-Mediated Streptococcus pyogenes Infections.}, journal = {mBio}, volume = {11}, number = {4}, pages = {}, pmid = {32636245}, issn = {2150-7511}, support = {R01 AI047928/AI/NIAID NIH HHS/United States ; T32 AI007540/AI/NIAID NIH HHS/United States ; R01 AI069568/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/drug effects/*growth & development ; Female ; Gene Expression Regulation, Bacterial ; Humans ; Hydrolases/*metabolism ; Male ; Metabolic Networks and Pathways ; Mice, Inbred C57BL ; Streptococcus pyogenes/*drug effects/enzymology ; }, abstract = {Bacterial biofilms are responsible for a variety of serious human infections and are notoriously difficult to treat due to their recalcitrance to antibiotics. Further work is necessary to elicit a full understanding of the mechanism of this antibiotic tolerance. The arginine deiminase (ADI) pathway is responsible for bacterial pH maintenance and is highly expressed during biofilm growth in multiple bacterial species. Using the group A Streptococcus (GAS) as a model human pathogen, the ADI pathway was demonstrated to contribute to biofilm growth. The inability of antibiotics to reduce GAS populations when in a biofilm was demonstrated by in vitro studies and a novel animal model of nasopharyngeal infection. However, disruption of the ADI pathway returned GAS biofilms to planktonic levels of antibiotic sensitivity, suggesting the ADI pathway is influential in biofilm-related antibiotic treatment failure and provides a new strategic target for the treatment of biofilm infections in GAS and potentially numerous other bacterial species.IMPORTANCE Biofilm-mediated bacterial infections are a major threat to human health because of their recalcitrance to antibiotic treatment. Through the study of Streptococcus pyogenes, a significant human pathogen that is known to form antibiotic-tolerant biofilms, we demonstrated the role that a bacterial pathway known for responding to acid stress plays in biofilm growth and antibiotic tolerance. This not only provides some insight into antibiotic treatment failure in S. pyogenes infections but also, given the widespread nature of this pathway, provides a potentially broad target for antibiofilm therapies. This discovery has the potential to impact the treatment of many different types of recalcitrant biofilm infections.}, } @article {pmid32636243, year = {2020}, author = {Park, JS and Choi, HY and Kim, WG}, title = {The Nitrite Transporter Facilitates Biofilm Formation via Suppression of Nitrite Reductase and Is a New Antibiofilm Target in Pseudomonas aeruginosa.}, journal = {mBio}, volume = {11}, number = {4}, pages = {}, pmid = {32636243}, issn = {2150-7511}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Chlorophenols/*pharmacology ; Escherichia coli/genetics ; Gene Expression Regulation, Bacterial ; Gene Library ; Nitric Oxide/metabolism ; Nitrite Reductases/*antagonists & inhibitors/genetics ; Nitrites/*metabolism ; Peptides, Cyclic/*pharmacology ; Pseudomonas aeruginosa/*drug effects/enzymology/genetics ; Virulence ; }, abstract = {Biofilm-forming bacteria, including the Gram-negative Pseudomonas aeruginosa, cause multiple types of chronic infections and are responsible for serious health burdens in humans, animals, and plants. Nitric oxide (NO) has been shown to induce biofilm dispersal via triggering a reduction in cyclic-di-GMP levels in a variety of bacteria. However, how NO, at homeostatic levels, also facilitates biofilm formation is unknown. Here, we found that complestatin, a structural analog of vancomycin isolated from Streptomyces, inhibits P. aeruginosa biofilm formation by upregulating NO production via nitrite reductase (NIR) induction and c-di-GMP degradation via phosphodiesterase (PDE) stimulation. The complestatin protein target was identified as a nitrite transporter from a genome-wide screen using the Keio Escherichia coli knockout library and confirmed using nitrite transporter knockout and overexpression strains. We demonstrated that the nitrite transporter stimulated biofilm formation by controlled NO production via appropriate NIR suppression and subsequent diguanylate cyclase (DGC) activation, not PDE activity, and c-di-GMP production in E. coli and P. aeruginosa Thus, this study provides a mechanism for NO-mediated biofilm formation, which was previously not understood.IMPORTANCE Bacterial biofilms play roles in infections and avoidance of host defense mechanisms of medically important pathogens and increase the antibiotic resistance of the bacteria. Nitric oxide (NO) is reported to be involved in both biofilm formation and dispersal, which are conflicting processes. The mechanism by which NO regulates biofilm dispersal is relatively understood, but there are no reports about how NO is involved in biofilm formation. Here, by investigating the mechanism by which complestatin inhibits biofilm formation, we describe a novel mechanism for governing biofilm formation in Escherichia coli and Pseudomonas aeruginosa Nitrite transporter is required for biofilm formation via regulation of NO levels and subsequent c-di-GMP production. Additionally, the nitrite transporter contributes more to P. aeruginosa virulence than quorum sensing. Thus, this study identifies nitrite transporters as new antibiofilm targets for future practical and therapeutic agent development.}, } @article {pmid32634677, year = {2020}, author = {Lai, CY and Song, Y and Wu, M and Lu, X and Wang, Y and Yuan, Z and Guo, J}, title = {Microbial selenate reduction in membrane biofilm reactors using ethane and propane as electron donors.}, journal = {Water research}, volume = {183}, number = {}, pages = {116008}, doi = {10.1016/j.watres.2020.116008}, pmid = {32634677}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; Electrons ; *Ethane ; Oxidation-Reduction ; *Propane ; Selenic Acid ; }, abstract = {Selenate (Se(VI)) contamination in groundwater is one of major concerns for human health, in particular in shale gas extraction sites. Microbial selenate reduction coupled to methane (CH4) oxidation has been demonstrated very recently. Little is known whether ethane (C2H6) and butane (C3H8) are able to drive selenate reduction, although they are also important components in shale gas. In this study, we demonstrated Se(VI) bio-reduction could be achieved using C2H6 and C3H8 as electron donors and carbon sources. Scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX) confirmed elemental Se (Se[0]) was the major final product formed from Se(VI) bio-reduction. Polyhydroxyalkanoates (PHAs) were generated in the biofilms as the internal electron-storage materials, which were consumed for sustaining Se(VI) bio-reduction in absence of C2H6 and C3H8. Microbial community analysis showed that two genera capable of oxidizing gaseous alkanes dominated in the biofilms, including Mycobacterium (in both C2H6 and C3H8-fed biofilms) and Rhodococcus (in C3H8-fed biofilm). In addition, several potential Se(VI) reducers (e.g., Variovorax) were detected in the biofilms. Investigation of Communities by Reconstruction of Unobserved States analysis supported that predictive genes associated with alkanes oxidation, denitrification and PHAs cycle were enriched in the biofilms. These findings offer insights into the process of selenate reduction driven by C2H6 and C3H8, which ultimately may help to develop a solution to use shale gas for groundwater remediation, especially near shale gas exploitation sites.}, } @article {pmid32634643, year = {2020}, author = {Lin, Z and Huang, W and Zhou, J and He, X and Wang, J and Wang, X and Zhou, J}, title = {The variation on nitrogen removal mechanisms and the succession of ammonia oxidizing archaea and ammonia oxidizing bacteria with temperature in biofilm reactors treating saline wastewater.}, journal = {Bioresource technology}, volume = {314}, number = {}, pages = {123760}, doi = {10.1016/j.biortech.2020.123760}, pmid = {32634643}, issn = {1873-2976}, mesh = {*Ammonia ; *Archaea ; Bacteria ; Biofilms ; Denitrification ; Nitrification ; Nitrogen ; Oxidation-Reduction ; Phylogeny ; Temperature ; Wastewater ; }, abstract = {To reveal nitrogen removal mechanisms under environmental stresses, biofilm reactors were operated at different temperatures (10 °C-35 °C) treating saline wastewater (salinity 3%). The results showed nitrogen removal efficiency was 98.46% at 30 °C and 60.85% at 10 °C, respectively. Both ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) participated in nitrification. 94.9% of the overall ammonia oxidation was attributed to AOA at 10 °C, but only 48.2% of that was undertaken by AOA at 35 °C. AOA had a greater contribution at low temperature, which demonstrated that nitrogen removal pathway varied with temperature. Aerobic denitrification was more stable than anoxic denitrification. High-throughput sequencing showed Crenarchaeota was the dominant AOA (97.02-34.47%), cooperating with various heterotrophic AOB. Real-time PCR indicated that AOA was three orders of magnitude more abundant than AOB. AOA was more resistant to low temperature and high-saline stresses. Ammonia oxidizers had distinct responses to temperature change and showed diverse relationships at different temperatures.}, } @article {pmid32634470, year = {2020}, author = {de Sá Almeida, JS and de Oliveira Marre, AT and Teixeira, FL and Boente, RF and Domingues, RMCP and de Paula, GR and Lobo, LA}, title = {Lactoferrin and lactoferricin B reduce adhesion and biofilm formation in the intestinal symbionts Bacteroides fragilis and Bacteroides thetaiotaomicron.}, journal = {Anaerobe}, volume = {64}, number = {}, pages = {102232}, doi = {10.1016/j.anaerobe.2020.102232}, pmid = {32634470}, issn = {1095-8274}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Bacteroides/*drug effects/*physiology ; Bacteroides fragilis/drug effects/physiology ; Bacteroides thetaiotaomicron/drug effects/physiology ; Biofilms/*drug effects ; Gastrointestinal Tract/microbiology ; Humans ; Lactoferrin/*pharmacology ; }, abstract = {Several factors affect the composition of species that inhabit our intestinal tract, including mode of delivery, genetics and nutrition. Antimicrobial peptides and proteins secreted in the gastrointestinal tract are powerful tools against bacteria. Lactoferrin (LF) inhibits the growth of several bacterial species, such as Enterobacteriaceae, but may stimulate probiotic bacteria. Activity of LF against gut symbiotic species of the Bacteroides genus could give us insights on how these species colonize the gut. We investigated the effects of the antimicrobial protein lactoferrin and its derived peptide, lactoferricin B on two species of strict anaerobes, opportunistic pathogens that cause diseases in both adults and children, commonly found in the microbiota of the human gastrointestinal tract, Bacteroides fragilis and B. thetaiotaomicron., In vitro biofilm formation and binding to laminin were strongly inhibited by a low concentration of lactoferrin (12.5 μg/ml). Conversely, the growth of the strains in a micro-dilution assay in minimal media with different iron sources was not affected by physiological concentrations (2 mg/ml) of apo-lactoferrin or holo-lactoferrin. The combination of lactoferrin with antibiotics in synergism assays was also negative. The lactoferricin B fragment was also unable to inhibit growth in a similar test with concentrations of up to 32 μg/ml. Resistance to lactoferrin could confer an advantage to these species, even when high amount of this protein is present in the gastrointestinal tract. However, colonization is hampered by the binding and biofilm inhibitiory effect of lactoferrin, which may explain the low prevalence of Bacteroides in healthy babies. Resistance to this antimicrobial protein may help understand the success of these opportunistic pathogens during infection in the peritoneum.}, } @article {pmid32633012, year = {2020}, author = {Yin, L and Zhu, W and Chen, D and Zhou, Y and Lin, H}, title = {Small noncoding RNA sRNA0426 is involved in regulating biofilm formation in Streptococcus mutans.}, journal = {MicrobiologyOpen}, volume = {9}, number = {9}, pages = {e1096}, pmid = {32633012}, issn = {2045-8827}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Metabolic Networks and Pathways ; Nucleic Acid Conformation ; Polysaccharides, Bacterial/*biosynthesis/genetics ; RNA, Bacterial/chemistry/genetics/*metabolism ; RNA, Messenger/genetics/metabolism ; RNA, Small Untranslated/chemistry/genetics/*metabolism ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*genetics/*physiology ; }, abstract = {Evidence suggests that small noncoding RNAs (sRNAs) are involved in the complex regulatory networks governing biofilm formation. Few studies have investigated the role of sRNAs in Streptococcus mutans (S. mutans). In the present study, the association between sRNA and biofilm formation in S. mutans was explored. sRNAs that are differentially expressed in the biofilm and planktonic states of this bacterium were identified by quantitative real-time PCR (qRT-PCR). Confocal laser scanning microscopy was used to investigate the characteristics of biofilm formation in a standard strain of S. mutans (UA159, ATCC 700610) and ten clinical strains. Bioinformatics analyses were employed to predict and examine potential sRNA regulatory pathways. The results showed that sRNA0426 has a strong positive relationship with dynamic biofilm formation. Moreover, sRNA0426 expression was positively correlated with exopolysaccharide (EPS) production. Bioinformatics analyses showed that sRNA0426 is involved in biofilm formation such as metabolic pathways, especially carbon metabolism. Five target mRNAs (GtfB, GtfC, GtfD, ComE, and CcpA) involved in the synthesis of EPS were selected for further evaluation; the expression levels of three of these mRNAs (GtfB, GtfC, and CcpA) were positively correlated with sRNA0426 expression levels, and the expression level of one (ComE) was negatively correlated. In conclusion, the results suggested that sRNA0426 may play an important and positive role in the biofilm formation of S. mutans and provide novel insight into the S. mutans biofilm regulatory network.}, } @article {pmid32632872, year = {2020}, author = {Thibeaux, R and Kainiu, M and Goarant, C}, title = {Biofilm Formation and Quantification Using the 96-Microtiter Plate.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2134}, number = {}, pages = {207-214}, doi = {10.1007/978-1-0716-0459-5_19}, pmid = {32632872}, issn = {1940-6029}, mesh = {Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Gentian Violet/chemistry ; High-Throughput Screening Assays/methods ; Leptospira/growth & development ; Mass Screening/methods ; Staining and Labeling/methods ; }, abstract = {Biofilm formation in microtiter plates is certainly the most commonly used method to grow and study biofilm. This simple design is very popular due to its high-throughput screening capacities, low cost, and easy handling. In the protocol described here, we focus on the use of 96-well optically clear, polystyrene flat-bottom plate to study biofilm formation by Leptospira spp. and quantify the biofilm formation by crystal violet (CV) staining. We also describe an alternative method, based on phase contrast image analysis that we believe is more suitable for accurately quantifying biofilm growth by reducing handling of this fragile structure.}, } @article {pmid32631946, year = {2020}, author = {Collins, AJ and Pastora, AB and Smith, TJ and O'Toole, GA}, title = {MapA, a Second Large RTX Adhesin Conserved across the Pseudomonads, Contributes to Biofilm Formation by Pseudomonas fluorescens.}, journal = {Journal of bacteriology}, volume = {202}, number = {18}, pages = {}, pmid = {32631946}, issn = {1098-5530}, support = {P30 CA023108/CA/NCI NIH HHS/United States ; R01 GM123609/GM/NIGMS NIH HHS/United States ; T32 AI007519/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*physiology ; *Bacterial Adhesion ; Biofilms/*growth & development ; Cell Membrane/metabolism ; Gene Expression Regulation, Bacterial ; Periplasm/metabolism ; Pseudomonas fluorescens/*physiology ; }, abstract = {Mechanisms by which cells attach to a surface and form a biofilm are diverse and differ greatly among organisms. The Gram-negative gammaproteobacterium Pseudomonas fluorescens attaches to a surface through the localization of the large type 1-secreted RTX adhesin LapA to the outer surface of the cell. LapA localization to the cell surface is controlled by the activities of a periplasmic protease, LapG, and an inner membrane-spanning cyclic di-GMP-responsive effector protein, LapD. A previous study identified a second, LapA-like protein encoded in the P. fluorescens Pf0-1 genome: Pfl01_1463. Here, we identified specific growth conditions under which Pfl01_1463, here called MapA (medium adhesion protein A) is a functional adhesin contributing to biofilm formation. This adhesin, like LapA, appears to be secreted through a Lap-related type 1 secretion machinery, and its localization is controlled by LapD and LapG. However, differing roles of LapA and MapA in biofilm formation are achieved, at least in part, through the differences in the sequences of the two adhesins and different distributions of the expression of the lapA and mapA genes within a biofilm. LapA-like proteins are broadly distributed throughout the Proteobacteria, and furthermore, LapA and MapA are well conserved among other Pseudomonas species. Together, our data indicate that the mechanisms by which a cell forms a biofilm and the components of a biofilm matrix can differ depending on growth conditions and the matrix protein(s) expressed.IMPORTANCE Adhesins are critical for the formation and maturation of bacterial biofilms. We identify a second adhesin in P. fluorescens, called MapA, which appears to play a role in biofilm maturation and whose regulation is distinct from the previously reported LapA adhesin, which is critical for biofilm initiation. Analysis of bacterial adhesins shows that LapA-like and MapA-like adhesins are found broadly in pseudomonads and related organisms, indicating that the utilization of different suites of adhesins may be broadly important in the Gammaproteobacteria.}, } @article {pmid32631880, year = {2020}, author = {Dal Co, A and Brenner, MP}, title = {Tracing cell trajectories in a biofilm.}, journal = {Science (New York, N.Y.)}, volume = {369}, number = {6499}, pages = {30-31}, doi = {10.1126/science.abd1225}, pmid = {32631880}, issn = {1095-9203}, mesh = {Bacteria ; *Biofilms ; Cell Differentiation ; *Microscopy ; }, } @article {pmid32628991, year = {2020}, author = {Mahdi, LH and Nazem Abdul-Hur, G and Auda, IG}, title = {Evidence of anti- K. pneumoniae biofilm activity of novel Entrococcus faecalis enterocin GLHM.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104366}, doi = {10.1016/j.micpath.2020.104366}, pmid = {32628991}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteriocins/pharmacology ; Biofilms ; Bridged-Ring Compounds ; *Enterococcus faecalis ; }, abstract = {Many enterocins were produced from the lactic acid bacteria, Enterococcus faecalis, they belonged to different types of bacteriocins and have different characteristics. The present study aimed to search for another enterocin and test its ability to inhibit Klebsiella pneumoniae biofilm as compared with the most effective antibacterial agent. E. faecalis isolates were isolated from stools of breastfeeding babies. Klebsiella pneumoniae isolates were from urinary tract infections and urinary catheters. K. pneumoniae isolates showed biofilm formation potential and multidrug resistance phenotype but amikacin was the most effective one. Enterocin production by gene harboring E. faecalis was screened, then enterocin was purified, characterized, and antibacterial activity and MIC of enterocin were determined. Produced enterocin has characteristics differ from other discovered enterocins. Furthermore, the crude and purified enterocin of E. faecalis possess significant antibacterial activity against K. pneumoniae isolates as compare with control (p < 0.05), and antibiofilm activity of enterocin was stronger than the antibiofilm activity of amikacin (P < 0.05), as well as the enterocin, was potent than the amikacin in preventing the formation of biofilm on the catheter. In conclusion, a novel enterocin was produced from Enterococcus faecalis (enterocin GLHM) is proteinous bacteriocin, relatively heat-stable and have full activity at neutral pH and was belong to type II bacteriocin. Enterocin GLHM have anti-K. pneumoniae and anti-K. pneumoniae biofilm significantly better than amikacin.}, } @article {pmid32626941, year = {2020}, author = {Tada, A and Nakayama-Imaohji, H and Yamasaki, H and Elahi, M and Nagao, T and Yagi, H and Ishikawa, M and Shibuya, K and Kuwahara, T}, title = {Effect of thymoquinone on Fusobacterium nucleatum‑associated biofilm and inflammation.}, journal = {Molecular medicine reports}, volume = {22}, number = {2}, pages = {643-650}, pmid = {32626941}, issn = {1791-3004}, mesh = {Actinomyces/cytology/drug effects/physiology ; Benzoquinones/*pharmacology ; Biofilms/*drug effects ; Fusobacterium nucleatum/cytology/*drug effects/*physiology ; Gingiva/drug effects ; Humans ; Inflammation/*metabolism ; Microscopy, Confocal ; Periodontitis/drug therapy/microbiology ; Plant Oils/chemistry ; THP-1 Cells ; Thymol/pharmacology ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {Periodontitis affects oral tissues and induces systemic inflammation, which increases the risk of cardiovascular disease and metabolic syndrome. Subgingival plaque accumulation is a trigger of periodontitis. Fusobacterium nucleatum (FN) contributes to subgingival biofilm complexity by intercalating with early and late bacterial colonizers on tooth surfaces. In addition, inflammatory responses to FN are associated with the progression of periodontitis. Nigella sativa Lin. seed, which is known as black cumin (BC), has been used as a herbal medicine to treat ailments such as asthma and infectious diseases. The current study examined the inhibitory effect of BC oil and its active constituents, thymol (TM) and thymoquinone (TQ), on FN‑associated biofilm and inflammation. FN‑containing biofilms were prepared by co‑cultivation with an early dental colonizer, Actinomyces naeslundii (AN). The stability and biomass of FN/AN dual species biofilms were significantly higher compared with FN alone. This effect was retained even with prefixed cells, indicating that FN/AN co‑aggregation is mediated by physicochemical interactions with cell surface molecules. FN/AN biofilm formation was significantly inhibited by 0.1% TM or TQ. Confocal laser scanning microscopy indicated that treatment of preformed FN/AN biofilm with 0.01% of BC, TM or TQ significantly reduced biofilm thickness, and TQ demonstrated a cleansing effect equivalent to that of isopropyl methylphenol. TQ dose‑dependently suppressed TNF‑α production from a human monocytic cell line, THP‑1 exposed to FN, yet showed no toxicity to THP‑1 cells. These results indicated that oral hygiene care using TQ could reduce FN‑associated biofilm and inflammation in gingival tissue.}, } @article {pmid32623704, year = {2020}, author = {Donmez, HG and Sahal, G and Akgor, U and Cagan, M and Ozgul, N and Beksac, MS}, title = {The relationship between the presence of HPV infection and biofilm formation in cervicovaginal smears.}, journal = {Infection}, volume = {48}, number = {5}, pages = {735-740}, pmid = {32623704}, issn = {1439-0973}, mesh = {Adult ; *Biofilms ; Cervix Uteri/virology ; Female ; Humans ; Middle Aged ; Papillomaviridae/*physiology ; Papillomavirus Infections/*physiopathology ; Turkey ; Vagina/virology ; *Vaginal Smears ; Young Adult ; }, abstract = {PURPOSE: To demonstrate and understand the association of HPV infection and biofilm formation.

METHODS: The study consisted of cervicovaginal samples of 72 women who were evaluated at the colposcopy unit. Papanicolaou staining was used for cytological examination while "Crystal Violet Binding" assay was performed to detect biofilm formation.

RESULTS: HPV-DNA was positive in 55.5% (n = 40) of the patients. The biofilm formation rate was statistically significantly higher in the HPV-positive women (45%) compared to HPV-negative women (21.9%) (P < 0.05). There was a statistically significant relationship between the presence of single HPV and "high-risk HPV" types and biofilm formation (P < 0.05). Biofilm formation was found in 80% of women with abnormal smear demonstrating atypical epithelial cells (P < 0.05).

CONCLUSION: Biofilm formation is more frequent at the cervicovaginal microbiota of patients with HPV infection. This finding is especially important in cases with atypical epithelial cells at their cervicovaginal smears.}, } @article {pmid32623133, year = {2020}, author = {Kunrath, MF and Monteiro, MSG and Gupta, S and Hubler, R and de Oliveira, SD}, title = {Influence of titanium and zirconia modified surfaces for rapid healing on adhesion and biofilm formation of Staphylococcus epidermidis.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104824}, doi = {10.1016/j.archoralbio.2020.104824}, pmid = {32623133}, issn = {1879-1506}, mesh = {*Bacterial Adhesion ; *Biofilms ; *Staphylococcus epidermidis ; Surface Properties ; *Titanium/pharmacology ; Zirconium/*pharmacology ; }, abstract = {OBJECTIVE: Surface alterations have been employed to enhance the osseointegration process in biomedical implants. However, these modifications may influence bacterial adhesion in different ways. Therefore, this study developed five different surfaces and evaluated the Staphylococcus epidermidis growth in early (1 h) and late (24 h) contact.

DESIGN: The Titanium (Ti) and Zirconia (Zr) surfaces were divided in five groups and characterized concerning your morphology, roughness, wettability and chemical surface composition. Then, were evaluated regarding bacterial adhesion and biofilm formation/thickness, viability and morphology.

RESULTS: Different topographies were manufactured resulting in a variety of combinations of surface properties. High roughness showed significantly higher bacterial adhesion in 1 h, while high hydrophilicity revealed greater bacterial proliferation in 24 h. Morphological changes were not found visually, however the viability test showed some cell membrane damage in the Ti micro and nano groups.

CONCLUSIONS: Finally, surface distinct properties influence the growth of S. epidermidis independent of the based-material. Furthermore, some surface properties require precautions for use in contaminated sites according to the increased adhesion of S. epidermidis presented when in contact.}, } @article {pmid32622258, year = {2020}, author = {Ayoub, HM and Gregory, RL and Tang, Q and Lippert, F}, title = {The anti-caries efficacy of three fluoride compounds at increasing maturation of a microcosm biofilm.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104781}, doi = {10.1016/j.archoralbio.2020.104781}, pmid = {32622258}, issn = {1879-1506}, mesh = {Biofilms/*drug effects ; Cariostatic Agents/*pharmacology ; *Dental Caries/drug therapy/prevention & control ; Fluorides/*pharmacology ; Humans ; Minerals ; Sodium Fluoride/pharmacology ; *Tooth Demineralization ; Tooth Remineralization ; }, abstract = {OBJECTIVE: To explore the anti-caries efficacy of three fluoride compounds at increasing maturation of a microcosm biofilm.

DESIGN: Microcosm biofilm, obtained from saliva collected from three donors (IRB #1406440799), was grown on enamel samples (n = 18/group) for 24-h (Brain Heart Infusion; 0.2 % sucrose). Then, pH cycling model started. Three maturations were explored (4d, 8d, and 12d). The pH cycling consisted of daily 2 × 5 min treatments (NaF, SnF2, AmF: 287.5 ppm F, and de-ionized water [DIW]), 4 × 10 min remineralization (BHI, no sucrose, pH 7.0), and 3 × 2:15 h demineralization (BHI, 1% sucrose, pH 4.5). We analyzed the enamel (surface microhardness [VHNchange], integrated mineral loss [ΔZ], lesion depth [L]), and the biofilm (viability [log10 CFU/mL], lactic acid production [LDH], and exopolysaccharide [EPS] amount). Data were analyzed using two-way ANOVA (p = 0.05).

RESULTS: The interaction between tested variables was significant for VHNchange, viability, LDH, EPS (p = 0.0354, p = 0.0001, p < 0.0001, p < 0.0001), but not for L (p = 0.2412) or ΔZ (p = 0.6811). LDH and EPS analyses exhibited more tolerance of mature biofilm against NaF (LDH and EPS p < 0.0001); NaF-treated groups demonstrated significantly lower results than the control in the 12d group. The effect of SnF2 and AmF continued over time. VHNchange, L, and ΔZ: The effect of SnF2 and AmF was higher than NaF and DIW. L and ΔZ did not result in significant differences over time (all treatments). Within each maturation, fluoride compounds demonstrated statistically significantly lower L and ΔZ values than DIW.

CONCLUSIONS: Biofilm's maturation may influence the selection of fluoride compounds to achieve an optimum cariostatic effect.}, } @article {pmid32622167, year = {2020}, author = {Hou, YN and Ma, JF and Yang, ZN and Sun, SY and Wang, AJ and Cheng, HY}, title = {Insight into the electrocatalytic performance of in-situ fabricated electroactive biofilm-Pd: The role of biofilm thickness, initial Pd(II) concentration and the exposure time to Pd precursor.}, journal = {The Science of the total environment}, volume = {742}, number = {}, pages = {140536}, doi = {10.1016/j.scitotenv.2020.140536}, pmid = {32622167}, issn = {1879-1026}, mesh = {Biofilms ; Catalysis ; Hydrogen ; *Nanoparticles ; *Palladium ; }, abstract = {Biogenic palladium (bio-Pd) nanoparticles have been considered as promising biocatalyst for energy generation and contaminants remediation in water and sediment. Recently, an electroactive biofilm-Pd (EAB-Pd) network, which can be used directly as electrocatalyst and show enhanced electrocatalytic performance, has exhibited tremendous application potential. However, the information regarding to the controllable biosynthetic process and corresponding catalytic properties is scarce. This study demonstrated that the catalytic performance of EAB-Pd could be influenced by Pd loading on bacteria cells (Pd/cells), which was crucial to determine the final distribution characteristic of Pd nanocrystal on EAB skeleton. For instance, the high Pd/cells (over 0.18 pg cell[-1]) exhibited almost 6-fold and 1.5-fold enhancement over EAB-Pds with Pd/cells below 0.03 in catalytic current toward hydrogen evolution reaction and nitrobenzene reduction, respectively. In addition, the Pd/cells was found to be affected by the synthesis factors, such as the ratio of biomass to initial Pd(II) concentration (cells/PdII) and the exposure time of EAB to Pd(II) precursor solution. The Pd/cells increased significantly as the cell/PdII ratio decreased from ~5.5 × 10[7] to ~1.3 × 10[7] cells L mg[-1] or the prolongation of exposure time from 3 h to 24 h. The findings developed in this work extensively expand our knowledge for the in-situ designing biogenic electrocatalyst and provide important information for the development of its catalytic property.}, } @article {pmid32622078, year = {2020}, author = {Skariyachan, S and Ravishankar, R and Gopal, D and Muddebihalkar, AG and Uttarkar, A and Praveen, PKU and Niranjan, V}, title = {Response regulator GacA and transcriptional activator RhlR proteins involved in biofilm formation of Pseudomonas aeruginosa are prospective targets for natural lead molecules: Computational modelling, molecular docking and dynamic simulation studies.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {85}, number = {}, pages = {104448}, doi = {10.1016/j.meegid.2020.104448}, pmid = {32622078}, issn = {1567-7257}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins/*chemistry ; Biofilms/*drug effects ; Drug Discovery ; Drug Evaluation, Preclinical ; Metabolic Networks and Pathways/drug effects ; Molecular Conformation ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Pentacyclic Triterpenes/*pharmacology ; Protein Binding ; Pseudomonas aeruginosa/*chemistry/*drug effects ; Transcription Factors/chemistry ; }, abstract = {Pseudomonas aeruginosa has become a global concern due to its extreme resistance to most of the last resort antibiotics. Present study focuses on the screening of potential molecular targets involved in regulation of biofilm formation in P. aeruginosa and identification of potential natural lead molecules against these targets by molecular modelling, docking and simulation studies. Response regulator (GacA) and transcriptional activator (RhlR) involved in biofilm formation in P. aeruginosa were identified as molecular targets by metabolic pathway analysis and the three dimensional structures of these proteins were predicted by homology modelling and validated. By thorough literature survey, 78 lead molecules were screened and their pharmacokinetic profiles were determined and best two of them selected. The binding potential of selected lead molecules against GacA and RhlR were predicted by molecular docking and their binding energy was compared with the interaction of meropenem and its usual target penicillin binding protein-3. The stabilities of best docked complex were studied by molecular dynamic (MD) simulation. This study showed that Celastrol present in Celastrus paniculatus and Rotiorinol present in Chaetomium cupreum showed better binding affinities with GacA (binding energy -7.2 kcal/mol) and RhlR (binding energy -8.0 kcal/mol) respectively in comparison with the binding of Meropenem and its target (binding energy -6.2 kcal/mol). MD simulation studies showed that GacA-Celastrol and RhlR-Rotiorinol complexes demonstrated conformational stability throughout the simulation. This study highlights the application of GacA and RhlR as prospective targets and Celastrol and Rotiorinol are the potential lead molecules towards biofilm producing drug resistant P. aeruginosa.}, } @article {pmid32621273, year = {2020}, author = {Nagaram, P and Pasupuleti, M and Arockiaraj, J}, title = {CxxC Zinc Finger Protein Derived Peptide, MF18 Functions Against Biofilm Formation.}, journal = {The protein journal}, volume = {39}, number = {4}, pages = {337-349}, doi = {10.1007/s10930-020-09904-1}, pmid = {32621273}, issn = {1875-8355}, mesh = {*Antimicrobial Cationic Peptides/chemistry/pharmacology ; Biofilms/*drug effects ; *DNA-Binding Proteins/chemistry/pharmacology ; Escherichia coli/*physiology ; Staphylococcus aureus/*physiology ; Zinc Fingers ; }, abstract = {The major threat in modern medicine was biofilm forming bacterial related infections and they were highly tolerant to conventional antibiotics and a boundless demand for new drugs. In this regard, antimicrobial peptide (AMP) have been considered as potential alternative agents to conventional antibiotics. In this study, we have reported a CxxC zinc finger protein derived peptide, MF18 and its various biological role including activity against biofilm forming bacteria. Zinc finger protein are important in regulation of several cellular processes and wide range of molecular functions. The CxxC zinc finger protein identified from the cDNA library of a teleost fish; further it was characterised using various online bioinformatics programs. During the in-silico analysis, an AMP named MF18 was identified from the CxxC zinc finger protein, then it was synthesised for further biological activity studies. The antimicrobial activity of MF18 was confirmed against the biofilm clinical isolates such as Staphylococcus aureus and Escherichia coli. The MIC of the antimicrobial peptide at the concentration of 320 µM was observed against these two biofilm bacteria. The mechanism of the peptides was determined using bacteria on its membrane permeabilization ability by scanning electron microscopy. It is exhibited that the MF18 potentially influenced in damaging the morphology of the bacteria. The toxicity of MF18 against the continuous cell line (RAW 264.7) was demonstrated by MTT assay and also using peripheral red blood cells by haemolytic assay; both assays showed that the peptide have no toxicity on the cells at lower concentration. Overall, the study showed the potential therapeutic application of the peptide in pharma industry.}, } @article {pmid32621125, year = {2020}, author = {Xiong, Q and Liu, D and Zhang, H and Dong, X and Zhang, G and Liu, Y and Zhang, R}, title = {Quorum sensing signal autoinducer-2 promotes root colonization of Bacillus velezensis SQR9 by affecting biofilm formation and motility.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {16}, pages = {7177-7185}, doi = {10.1007/s00253-020-10713-w}, pmid = {32621125}, issn = {1432-0614}, support = {31670113//National Natural Science Foundation of China/ ; 31870096//National Natural Science Foundation of China/ ; 2018YFD0500201//National Key R & D Program of China/ ; }, mesh = {Bacillus/*genetics/*physiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/genetics ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Homoserine/*analogs & derivatives/genetics ; Lactones ; Luminescent Measurements ; Movement ; Plant Roots/*microbiology ; *Quorum Sensing ; }, abstract = {Root colonization of beneficial rhizobacteria is critical for their beneficial effects. Quorum sensing (QS) has been reported to affect the colonization of many plant pathogens. However, how QS signals regulate root colonization of beneficial rhizobacteria is unclear. In this study, the QS signal AI-2 synthetase-encoding gene luxS was completely deleted from the genome of the plant beneficial rhizobacterium Bacillus velezensis SQR9, and bioluminescence experiments showed that AI-2 production was blocked. Deletion of luxS reduced biofilm formation, motility, and root colonization of B. velezensis SQR9, while addition of exogenous AI-2 to the mutant restored this phenomenon. These results indicated that AI-2 positively affects the root colonization of B. velezensis SQR9. This study provided new insights for enhancing the colonization of beneficial rhizobacteria. KEY POINTS: • LuxS participated in the synthesis of the quorum sensing signal AI-2 in B. velezensis. • AI-2 enhanced motility, biofilm formation, and root colonization of B. velezensis. • AI-2 stimulated the production of γ-polyglutamic acid by B. velezensis.}, } @article {pmid32620785, year = {2020}, author = {Daood, U and Matinlinna, JP and Pichika, MR and Mak, KK and Nagendrababu, V and Fawzy, AS}, title = {A quaternary ammonium silane antimicrobial triggers bacterial membrane and biofilm destruction.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {10970}, pmid = {32620785}, issn = {2045-2322}, mesh = {Aminoacyltransferases/antagonists & inhibitors ; Anti-Infective Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/antagonists & inhibitors/chemistry/drug effects ; Biofilms/*drug effects/growth & development ; Cysteine Endopeptidases ; Dental Caries/drug therapy/microbiology ; Dental Plaque/drug therapy/microbiology ; Dentin/drug effects/microbiology/ultrastructure ; Disinfectants/pharmacology ; Humans ; In Vitro Techniques ; Lactobacillus acidophilus/drug effects/physiology ; Microscopy, Electron, Scanning ; Molecular Docking Simulation ; Mouth/microbiology ; Quaternary Ammonium Compounds/*pharmacology ; Silanes/*pharmacology ; Streptococcus mutans/drug effects/physiology ; }, abstract = {To study the antimicrobial effects of quaternary ammonium silane (QAS) exposure on Streptococcus mutans and Lactobacillus acidophilus bacterial biofilms at different concentrations. Streptococcus mutans and Lactobacillus acidophilus biofilms were cultured on dentine disks, and incubated for bacterial adhesion for 3-days. Disks were treated with disinfectant (experimental QAS or control) and returned to culture for four days. Small-molecule drug discovery-suite was used to analyze QAS/Sortase-A active site. Cleavage of a synthetic fluorescent peptide substrate, was used to analyze inhibition of Sortase-A. Raman spectroscopy was performed and biofilms stained for confocal laser scanning microscopy (CLSM). Dentine disks that contained treated dual-species biofilms were examined using scanning electron microscopy (SEM). Analysis of DAPI within biofilms was performed using CLSM. Fatty acids in bacterial membranes were assessed with succinic-dehydrogenase assay along with time-kill assay. Sortase-A protein underwent conformational change due to QAS molecule during simulation, showing fluctuating alpha and beta strands. Spectroscopy revealed low carbohydrate intensities in 1% and 2% QAS. SEM images demonstrated absence of bacterial colonies after treatment. DAPI staining decreased with 1% QAS (p < 0.05). Fatty acid compositions of dual specie biofilm increased in both 1% and 2% QAS specimens (p < 0.05). Quaternary ammonium silane demonstrated to be a potent antibacterial cavity disinfectant and a plaque inhibitor and can be of potential significance in eliminating caries-forming bacteria.}, } @article {pmid32620725, year = {2020}, author = {Kelten, OS and Hepdeniz, OK and Tuncer, Y and Kankaya, DA and Gurdal, O}, title = {Effect of surface characteristic of different restorative materials containing glass ionomer on Streptococcus mutans biofilm.}, journal = {Nigerian journal of clinical practice}, volume = {23}, number = {7}, pages = {957-964}, doi = {10.4103/njcp.njcp_538_19}, pmid = {32620725}, issn = {1119-3077}, mesh = {Acrylic Resins ; Apatites/*chemistry ; Biofilms/*growth & development ; Composite Resins/chemistry/*pharmacology ; Dental Plaque/microbiology/*prevention & control ; Dental Restoration, Permanent ; Glass Ionomer Cements/*chemistry ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Silicon Dioxide ; Streptococcus mutans/drug effects/*growth & development ; Surface Properties ; }, abstract = {AIM: The aims of this study were to evaluate the surface morphology and surface roughness of restorative materials containing glass ionomer, analyze Streptococcus mutans biofilm formation on the surface of materials, and determine the correlation between surface roughness and biofilm.

MATERIALS AND METHODS: Four restorative materials: resin-modified glass ionomer; giomer; amalgomer; and glass carbomer were used and for each material, 6 mm in diameter and 2 mm in thickness disc-shaped specimens were prepared to evaluate the surface morphology (n = 3), surface roughness (n = 16), and biofilm (n = 20). Surface morphology was analyzed with a scanning electron microscope. Surface roughness was evaluated via an atomic force microscope. The biofilm was evaluated by counting the colony-forming units. Surface roughness measurements were evaluated using a one-way analysis of variance and Tukey HSD test. Biofilm parameters were analyzed using the Kruskal-Wallis H and Mann-Whitney U test. Pearson's correlation test was used to determine the correlation between surface roughness and biofilm.

RESULTS: While the highest roughness values were obtained for amalgomer and glass carbomer, the lowest roughness values belonged to giomer and resin-modified glass ionomer. Statistically significant differences in the number of adherent bacteria were observed between the materials only on day 1. No statistically significant correlation was determined between surface roughness and biofilm.

CONCLUSIONS: The resin content and small filler particle size of material positively affect surface roughness. However, there is no direct relationship between surface roughness and biofilm.}, } @article {pmid32619807, year = {2020}, author = {Zhang, P and Ding, XS and Zhao, B and An, Q and Guo, JS}, title = {Acceleration of biofilm formation in start-up of sequencing batch biofilm reactor using carriers immobilized with Pseudomonas stutzeri strain XL-2.}, journal = {Bioresource technology}, volume = {314}, number = {}, pages = {123736}, doi = {10.1016/j.biortech.2020.123736}, pmid = {32619807}, issn = {1873-2976}, mesh = {Acceleration ; Biofilms ; Bioreactors ; Nitrogen ; *Pseudomonas stutzeri ; Waste Disposal, Fluid ; }, abstract = {P. stutzeri strain XL-2 initially immobilized on polypropylene carriers accelerated the biofilm formation in start-up of sequencing batch biofilm reactor (SBBR) (denoted R1). The biofilm formation in R1 was approximately completed in 36 days, which was shorter than that of 48 days in an identical SBBR (denoted R2) without strain XL-2. Meanwhile, R1 presented a rapid stabilization of NH4[+]-N and TN removal to 81.7% and 72.4% respectively. Surface plasmon resonance demonstrated that strain XL-2 enhanced the initial adhesion of carrier surface due to the production of extracellular polymeric substances (EPS), which made it easier for other EPS-producing strains, such as Thauera and Flavobacterium, to adhere to the carriers. PICRUSt revealed that biofilm in R1 presented relatively higher activity of EPS biosynthesis enzymes (glycosyltransferase and asparagine synthase). Thus, high EPS content was obtained due to the application of carriers immobilized with strain XL-2 and finally promoted the biofilm formation.}, } @article {pmid32619353, year = {2020}, author = {Cordeiro, RA and de Andrade, ARC and Portela, FVM and Pereira, LMG and Moura, SGB and Sampaio, MD and Pereira, EMA and de Melo Guedes, GM and Bandeira, SP and de Lima-Neto, RG and Melo, VMM and Brilhante, RSN and Castelo-Branco, DSCM and Rocha, MFG and Sidrim, JJC}, title = {Proposal for a microcosm biofilm model for the study of vulvovaginal candidiasis.}, journal = {Biofouling}, volume = {36}, number = {5}, pages = {610-620}, doi = {10.1080/08927014.2020.1785435}, pmid = {32619353}, issn = {1029-2454}, mesh = {Antifungal Agents/*therapeutic use ; *Biofilms ; Candida albicans ; Candidiasis, Vulvovaginal/*drug therapy ; Female ; Fluconazole ; Humans ; Microbial Sensitivity Tests ; }, abstract = {This study proposes a microcosm biofilm (MiB) model for the study of vulvovaginal candidiasis (VVC). Different conditions that mimic the vaginal environment were tested for MiB formation. The best growth conditions were obtained with samples incubated in vaginal fluid simulator medium pH 4.5 at 35 °C under a microaerophilic atmosphere. MiBs were evaluated for growth kinetics, fluconazole susceptibility and morphology. Samples containing high numbers of bacteria were analyzed for metagenomics. At 48 h, MiBs presented a higher cell density (CFU ml[-1]), a higher biomass and tolerance to fluconazole than their corresponding monospecies biofilms. Morphological analysis of MiBs revealed blastoconidia preferentially adhered to epithelial cells. Abundant Lactobacillus spp. were detected in two clinical samples; their MiBs showed a lower biomass and a higher fluconazole susceptibility. The proposed model proved to be a useful tool for the study of the complex microbial relationship in the vaginal environment, and may help to find new strategies for VVC control.}, } @article {pmid32619289, year = {2021}, author = {Wu, Z and Zheng, R and Zhang, J and Wu, S}, title = {Transcriptional profiling of Pseudomonas aeruginosa PAO1 in response to anti-biofilm and anti-infection agent exopolysaccharide EPS273.}, journal = {Journal of applied microbiology}, volume = {130}, number = {1}, pages = {265-277}, doi = {10.1111/jam.14764}, pmid = {32619289}, issn = {1365-2672}, support = {31600035//National Natural Science Foundation of China/ ; //Chinese Academy of Sciences/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Extracellular Matrix/drug effects/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Polysaccharides/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects/genetics ; Transcriptome/*drug effects ; Virulence Factors/genetics ; }, abstract = {AIMS: Relatively, few anti-biofilm polysaccharides against Pseudomonas aeruginosa were done to investigate the underlying molecular mechanism. Exopolysaccharide EPS273 can clearly reduce biofilm formation and infection of P. aeruginosa. This study aims to investigate its anti-biofilm and anti-infection mechanism on transcriptional level.

METHODS AND RESULTS: Herein, we used an RNA-Seq transcriptomic approach to investigate the underlying anti-biofilm and anti-infection mechanism of EPS273. The expression levels of a large number of genes were changed after P. aeruginosa PAO1 was treated with EPS273. Especially, the genes related to biofilm formation, such as gene involved in production of extracellular matrix and virulence factor, genes involved in flagella and cell motility and genes involved in iron acquisition. Notably, the expression levels of genes involved in regulatory and signal transduction were markedly downregulated, such as two-component system PhoP-PhoQ and quorum sensing (QS) system LasI/LasR and RhlI/RhlR. Furthermore, when genes phoP and phoQ were disrupted, respectively, the reduction of biofilm formation and cell motility in mutant △phoP or △phoQ was also detected.

CONCLUSION: EPS273 may exert its anti-biofilm and anti-infection function by downregulating gene expression of two-component system PhoP-PhoQ and QS systems LasI/LasR and RhlI/RhlR of P. aeruginosa, which further regulated expression of genes involved in biofilm formation.

Our data will expand understanding of anti-biofilm mechanisms of polysaccharides on transcriptomic level.}, } @article {pmid32619153, year = {2020}, author = {da Silva, ACB and Sardi, JCO and de Oliveira, DGL and de Oliveira, CFR and Dos Santos, HF and Dos Santos, EL and Crusca, E and Cardoso, MH and Franco, OL and Macedo, MLR}, title = {Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda.}, journal = {Biofouling}, volume = {36}, number = {5}, pages = {516-527}, doi = {10.1080/08927014.2020.1776857}, pmid = {32619153}, issn = {1029-2454}, mesh = {Animals ; Antifungal Agents/*pharmacology ; *Biofilms ; *Candida ; Candida albicans ; Humans ; Microbial Sensitivity Tests ; Peptides ; Profilins/*pharmacology ; Spodoptera/*microbiology ; }, abstract = {Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide-PEP-IA18-was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5 µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10 × MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.}, } @article {pmid32616121, year = {2020}, author = {Liu, Y and Zeng, R and Duan, Z and Xu, H and Wu, Q and Chen, Q and Lin, T and Li, M}, title = {[Effect of 5-aminolevulinic Acid Photodynamics Therapy on Biofilm of Propionibacterium Acnes].}, journal = {Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae}, volume = {42}, number = {3}, pages = {283-288}, doi = {10.3881/j.issn.1000-503X.11774}, pmid = {32616121}, issn = {1000-503X}, mesh = {Aminolevulinic Acid ; *Biofilms ; Photochemotherapy ; Photosensitizing Agents ; Propionibacterium acnes ; }, abstract = {Objective To investigate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) on Propionibacterium acnes (P.acnes) biofilm. Methods P.acnes biofilms were constructed on a cell slide and treated with ALA-PDT.According to different light doses,the biofilms were divided into six groups:ALA-PDT group [ALA-PDT1 (50 J/cm[2]),ALA-PDT2 group (100 J/cm[2]),ALA-PDT3 group (200 J/cm[2])],ALA-only group (ALA group),light-only group (LED),and a negative control group (ALA-PDT-group).The biofilm structure and the ratio of the dead bacteria/live bacteria were observed using a laser confocal microscope (CLSM).Biofilm viability was measured using the XTT assay. Results CLSM showed that the biofilm structures of ALA group and LED group were not significantly different from that of ALA-PDT-group,whereas the biofilm structure was more seriously damaged in ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group than in the ALA-PDT-group.The ratios of the dead/live bacteria in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group were 0.350±0.033, 0.305±0.046, 0.330±0.032, 1.525±0.439, 2.293±0.148 and 3.092±0.189,respectively.ALA group(md=0.003, P=1.000)and LED group(md=-0.025, P=1.000)did not significantly differ from the ALA-PDT-group.However,the ratio of dead/live bacteria in ALA-PDT-group was significantly lower than those in ALA-PDT1 group (md=-0.162, P<0.001),ALA-PDT2 group (md=-0.254, P<0.001),and ALA-PDT3 group (md=-0.352, P<0.001).The values of the XTT assay were were 0.462±0.028,0.465±0.044,0.437±0.047,0.301±0.040,0.207±0.001,and 0.110±0.007,respectively,in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group.Although the values of XTT assay in ALA(md=-0.044, P=1.000)and LED groups (md=-0.020, P=1.000)did not significantly differ from that in ALA-PDT-group,it was significantly higher in ALA-PDT-group than in ALA-PDT1 group (md=1.175, P<0.001),ALA-PDT2 group (md=1.942, P<0.001),and ALA-PDT3 group (md=-0.352, md=2.742, P<0.001). Conclusions ALA-PDT has an inhibitory effect on P.acnes biofilm.ALA-PDT destroys biofilm structure and inhibits biofilm viability.}, } @article {pmid32615520, year = {2020}, author = {Chaves, S and Longo, M and Gómez López, A and Del V Loto, F and Mechetti, M and Romero, CM}, title = {Control of microbial biofilm formation as an approach for biomaterials synthesis.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {194}, number = {}, pages = {111201}, doi = {10.1016/j.colsurfb.2020.111201}, pmid = {32615520}, issn = {1873-4367}, mesh = {*Biocompatible Materials ; *Biofilms ; Enzymes, Immobilized ; Rheology ; Viscosity ; }, abstract = {The search for new biomaterials with superior mechanical properties is the focus in the area of materials science. A promising pathway is drawing inspiration from nature to design and develop materials with enhanced properties. In this work, a novel strategy to produce functionalized supramolecular bionanomaterials from the microbial biofilm is reported. Tuneable biofilms with specific characteristics were obtained by controlling the culture condition of the microorganism. When the exopolysaccharide (EPS) production was desired the tryptone was the best nutritional component for the EPS production into the biofilm. However, for the expression of a high amount of amyloid protein the combination of peptone and glucose was the best nutritional choice. Each biofilm obtained showed its owner rheology properties. These properties were altered by the addition of extracellular DNA, which increased the viscosity of the biofilm and induced a viscoelastic hydrogel behavior. Besides, as a proof of concept of bionanomaterial, a novel supramolecular polymeric hybrid EPS-Amyloid protein (EPAP) was obtained from the biofilm and it was tested as a new natural functionalized support for enzyme immobilization. The results suggest that this technology could be used as a new concept to obtain biomaterials from biofilms by controlling the nutritional conditions of a microorganism. Understanding environmental factors affecting biofilm formation will help the development of methods for controlling biofilm production and therefore obtaining new biomaterials.}, } @article {pmid32614918, year = {2020}, author = {Moussa, DG and Aparicio, C}, title = {Targeting the oral plaque microbiome with immobilized anti-biofilm peptides at tooth-restoration interfaces.}, journal = {PloS one}, volume = {15}, number = {7}, pages = {e0235283}, pmid = {32614918}, issn = {1932-6203}, support = {R01 DE026117/DE/NIDCR NIH HHS/United States ; R90 DE023058/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*administration & dosage/pharmacology ; Antimicrobial Cationic Peptides/*administration & dosage/pharmacology ; Biofilms/*drug effects/growth & development ; Coated Materials, Biocompatible/chemistry ; Dental Plaque/*drug therapy ; Dentin/chemistry/microbiology ; Durapatite/chemistry ; Humans ; Immobilized Proteins/administration & dosage/pharmacology ; Microbiota/drug effects ; }, abstract = {Recurrent caries, the development of carious lesions at the interface between the restorative material and the tooth structure, is highly prevalent and represents the primary cause for failure of dental restorations. Correspondingly, we exploited the self-assembly and strong antibiofilm activity of amphipathic antimicrobial peptides (AAMPs) to form novel coatings on dentin that aimed to prevent recurrent caries at susceptible cavosurface margins. AAMPs are alternative to traditional antimicrobial agents and antibiotics with the ability to target the complex and heterogeneous organization of microbial communities. Unlike approaches that have focused on using these AAMPs in aqueous solutions for a transient activity, here we assess the effects on microcosm biofilms of a long-acting AAMPs-based antibiofilm coating to protect the tooth-composite interface. Genomewise, we studied the impact of AAMPs coatings on the dental plaque microbial community. We found that non-native all D-amino acids AAMPs coatings induced a marked shift in the plaque community and selectively targeted three primary acidogenic colonizers, including the most common taxa around Class II composite restorations. Accordingly, we investigated the translational potential of our antibiofilm dentin using multiphoton pulsed near infra-red laser for deep bioimaging to assess the impact of AAMPs-coated dentin on plaque biofilms along dentin-composite interfaces. Multiphoton enabled us to record the antibiofilm potency of AAMPs-coated dentin on plaque biofilms throughout exaggeratedly failed interfaces. In conclusion, AAMPs-coatings on dentin showed selective and long-acting antibiofilm activity against three dominant acidogenic colonizers and potential to resist recurrent caries to promote and sustain the interfacial integrity of adhesive-based interfaces.}, } @article {pmid32612893, year = {2020}, author = {Dosler, S and Hacioglu, M and Yilmaz, FN and Oyardi, O}, title = {Biofilm modelling on the contact lenses and comparison of the in vitro activities of multipurpose lens solutions and antibiotics.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e9419}, pmid = {32612893}, issn = {2167-8359}, abstract = {During the contact lens (CL) usage, microbial adhesion and biofilm formation are crucial threats for eye health due to the development of mature biofilms on CL surfaces associated with serious eye infections such as keratitis. For CL related eye infections, multi drug resistant Pseudomonas aeruginosa or Staphylococcus aureus (especially MRSA) and Candida albicans are the most common infectious bacteria and yeast, respectively. In this study, CL biofilm models were created by comparing them to reveal the differences on specific conditions. Then the anti-biofilm activities of some commercially available multipurpose CL solutions (MPSs) and antibiotic eye drops against mature biofilms of S. aureus, P. aeruginosa, and C. albicans standard and clinical strains were determined by the time killing curve (TKC) method at 6, 24 and 48 h. According to the biofilm formation models, the optimal biofilms occurred in a mixture of bovine serum albumin (20% v/v) and lysozyme (2 g/L) diluted in PBS at 37 °C for 24 h, without shaking. When we compared the CL types under the same conditions, the strongest biofilms according to their cell density, were formed on Pure Vision ≥ Softens 38 > Acuve 2 ∼ Softens Toric CLs. When we compared the used CLs with the new ones, a significant increase at the density of biofilms on the used CLs was observed. The most active MPS against P. aeruginosa and S. aureus biofilms at 24 h was Opti-Free followed by Bio-True and Renu according to the TKC analyses. In addition, the most active MPS against C. albicans was Renu followed by Opti-Free and Bio-True at 48 h. None of the MPSs showed 3 Log bactericidal/fungicidal activity, except for Opti-Free against S. aureus and P. aeruginosa biofilms during 6 h contact time. Moreover, all studied antibiotic eye drops were active against S. aureus and P. aeruginosa biofilms on CLs at 6 h and 24 h either directly or as 1/10 concentration, respectively. According to the results of the study, anti-biofilm activities of MPSs have changed depending on the chemical ingredients and contact times of MPSs, the type of infectious agent, and especially the CL type and usage time.}, } @article {pmid32612729, year = {2020}, author = {Li, T and Zhang, Z and Wang, F and He, Y and Zong, X and Bai, H and Liu, Z}, title = {Antimicrobial Susceptibility Testing of Metronidazole and Clindamycin against Gardnerella vaginalis in Planktonic and Biofilm Formation.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2020}, number = {}, pages = {1361825}, pmid = {32612729}, issn = {1712-9532}, abstract = {BACKGROUND: Bacterial vaginosis (BV), one of the most common vaginal ecosystem-related microbiologic syndromes, is the most common disorder in women of reproductive age. Gardnerella (G.) vaginalis is the predominant species causing this infection. Our aim was to compare the antimicrobial susceptibilities of metronidazole and clindamycin against G. vaginalis at planktonic and biofilm levels.

METHODS: From September 2019 to October 2019, we recruited a total of 10 patients with BV who underwent gynecological examinations at Beijing Obstetrics and Gynecology Hospital. G. vaginalis isolates were obtained from the vagina and identified using their characteristic colony morphology. Sequence data of clinical G. vaginalis isolates were confirmed by comparing 16S rDNA sequences. Subsequently, clinical isolates were evaluated for antimicrobial susceptibilities in vitro to metronidazole and clindamycin at planktonic and biofilm levels. The minimum inhibitory concentration (MIC) for metronidazole and clindamycin was evaluated by antimicrobial susceptibility testing. The minimum biofilm eradication concentration (MBEC) was evaluated by the biofilm inhibition assay.

RESULTS: Planktonic clinical isolates showed a significantly higher susceptibility rate (76.67%) and lower resistance rate (23.33%) to clindamycin than to metronidazole (susceptibility rate: 38.24%; resistance rate: 58.82%; P < 0.05 for both). Furthermore, in comparison to planktonic isolates, the minimum inhibitory concentration (MIC) of metronidazole was significantly higher for biofilm-forming isolates (7.3 ± 2.6 μg/mL vs. 72.4 ± 18.3 μg/mL; P=0.005); the resistance rate was 27.3%, and the minimum biofilm eradication concentration (MBEC) was >128 μg/mL. Moreover, the MIC of clindamycin was higher too for biofilm-forming isolates (0.099 ± 0.041 μg/mL vs. 23.7 ± 9.49 μg/mL; P=0.034); the resistance rate was 27.3%, and the MBEC of clindamycin was 28.4 ± 6.50 μg/mL.

CONCLUSION: Our results indicate that in comparison to metronidazole, clindamycin seems to be a better choice to tackle G. vaginalis as it exhibits a relatively higher susceptibility rate and lower resistance rate.}, } @article {pmid32610234, year = {2020}, author = {Zhuang, Z and Yang, G and Mai, Q and Guo, J and Liu, X and Zhuang, L}, title = {Physiological potential of extracellular polysaccharide in promoting Geobacter biofilm formation and extracellular electron transfer.}, journal = {The Science of the total environment}, volume = {741}, number = {}, pages = {140365}, doi = {10.1016/j.scitotenv.2020.140365}, pmid = {32610234}, issn = {1879-1026}, mesh = {Biofilms ; Electrons ; Ferric Compounds ; *Geobacter ; Oxidation-Reduction ; Polysaccharides ; }, abstract = {Geobacter sulfurreducens biofilms have promising applications in renewable energy, pollutant bioremediation, and bioelectronic applications. Genetically manipulating G. sulfurreducens biofilms is an effective strategy to improve the capacity of extracellular electron transfer (EET). Extracellular polysaccharide, a sticky component surrounding microbes, plays an important role in EET. Herein, we constructed a mutant of G. sulfurreducens strain PCA overexpressing the gene GSU1501 (part of the ATP-dependent exporter of the polysaccharide biosynthesis gene operon), designated strain PCA-1501, to increase EET capacity. Experimental results showed that the overexpression of GSU1501 increased extracellular polysaccharide secretion by 25.5%, which promoted the formation of biofilm with higher thickness and viability, as well as the content of extracellular c-type cytochromes. Compared with the control strain, the mutant showed a higher capacity of Fe(III) oxide reduction and current generation (increased by 20.4% and 22.2%, respectively). Interestingly, the overexpression of GSU1501 hindered the pili formation by reducing the transcription level of pilA; a compensatory relationship between extracellular polysaccharide and pili in promoting biofilm formation deserves further investigation. This study provides a feasible method to promote the EET capacity of G. sulfurreducens biofilms, which benefit their bioelectrochemical applications.}, } @article {pmid32609185, year = {2020}, author = {Jain, A and Armstrong, SR and Banas, JA and Qian, F and Maia, RR and Teixeira, EC}, title = {Dental adhesive microtensile bond strength following a biofilm-based in vitro aging model.}, journal = {Journal of applied oral science : revista FOB}, volume = {28}, number = {}, pages = {e20190737}, pmid = {32609185}, issn = {1678-7765}, mesh = {Biofilms ; Composite Resins ; *Dental Bonding ; Dental Cements ; Dentin ; *Dentin-Bonding Agents ; Materials Testing ; Resin Cements ; Tensile Strength ; }, abstract = {OBJECTIVE: Laboratory tests are routinely used to test bonding properties of dental adhesives. Various aging methods that simulate the oral environment are used to complement these tests for assessment of adhesive bond durability. However, most of these methods challenge hydrolytic and mechanical stability of the adhesive- enamel/dentin interface, and not the biostability of dental adhesives. To compare resin-dentin microtensile bond strength (μTBS) after a 15-day Streptococcus mutans (SM) or Streptococcus sobrinus (SS) bacterial exposure to the 6-month water storage (WS) ISO 11405 type 3 test.

METHODOLOGY: A total of 31 molars were flattened and their exposed dentin was restored with Optibond-FL adhesive system and Z-100 dental composite. Each restored molar was sectioned and trimmed into four dumbbell-shaped specimens, and randomly distributed based on the following aging conditions: A) 6 months of WS (n=31), B) 5.5 months of WS + 15 days of a SM-biofilm challenge (n=31), C) 15 days of a SM-biofilm challenge (n=31) and D) 15 days of a SS-biofilm challenge (n=31). μTBS were determined and the failure modes were classified using light microscopy.

RESULTS: Statistical analyses showed that each type of aging condition affected μTBS (p<0.0001). For Group A (49.7±15.5MPa), the mean μTBS was significantly greater than in Groups B (19.3±6.3MPa), C (19.9±5.9MPa) and D (23.6±7.9MPa). For Group D, the mean μTBS was also significantly greater than for Groups B and C, but no difference was observed between Groups B and C.

CONCLUSION: A Streptococcus mutans- or Streptococcus sobrinus-based biofilm challenge for 15 days resulted in a significantly lower μTBS than did the ISO 11405 recommended 6 months of water storage. This type of biofilm-based aging model seems to be a practical method for testing biostability of resin-dentin bonding.}, } @article {pmid32608853, year = {2020}, author = {Qin, JW and Xin, X and Lu, H and Zhang, PP and Wang, LR and Zou, CW and Guo, JY}, title = {[Bacterial Community Shifts and Nitrogen Removal Characteristics for a SNAD Process Treating Anaerobic Digester Liquor of Swine Wastewater (ADLSW) in a Continuous-Flow Biofilm Reactor (CFBR)].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {41}, number = {5}, pages = {2349-2357}, doi = {10.13227/j.hjkx.201910018}, pmid = {32608853}, issn = {0250-3301}, mesh = {Anaerobiosis ; Animals ; Bacteria ; Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Oxidation-Reduction ; Sewage ; Swine ; *Wastewater ; }, abstract = {To realize a simultaneous partial nitrification, ANAMMOX (anaerobic ammonium oxidation), and denitrification (SNAD) process treating anaerobic digester liquor of swine wastewater (ADLSW) in a continuous-flow biofilm reactor (CFBR), we first gradually increased the influent ammonium (NH4[+]-N) concentration, and then enhanced the ADLSW ratio in the influent during operation; dissolved oxygen (DO) was controlled at (0.4±0.1) mg·L[-1] by adjusting the air flow rate, and the temperature was kept at (30±1)℃. Meanwhile, high-throughput sequencing and quantitative PCR (polymerase chain reaction) techniques were used to analyze the bacterial community shifts and the amount of dominant nitrogen removal bacteria. The results demonstrated that a successful start-up of the SNAD process was accomplished in 150 d, and replacement of the actual biogas slurry was completed in 298 d. The effluent (NO3[-]-N+NO2[-]-N)/ΔNH4[+]-N value was less than 0.11, and the average removal rates of NH4[+]-N and TN (total nitrogen) increased to 63.26% and 55.71%, respectively. Moreover, high-throughput sequencing results demonstrated that the dominant microbial populations at phylum level were Chloroflexi (with a relative abundance of 50.78%), Proteobacteria (13.34%), and Planctomycetes (9.26%). The relative abundance of Nitrosomonas increased from 1.55% to 1.98%. In addition, the relative abundance of Candidatus_Brocadia and Candidatus_Kuenenia increased from 0.01% and (<0.01%) to 4.66% and 4.18%, respectively, and the relative abundance of Denitratisoma increased from (<0.01%) to 2.06%. Meanwhile, qPCR analysis showed that the amounts of ammonia-oxidizing bacteria, ANAMMOX, and denitrifying bacteria increased significantly compared with the inoculated sludge. An efficient and stable nitrogen removal rate can be achieved, and the follow-up processing cost can be reduced, by application of the SNAD treatment process for ADLSW.}, } @article {pmid32608741, year = {2020}, author = {Zhao, ZR and Zhang, JY and Li, D and Li, FH}, title = {[Purification Characteristics of Urban Tail Water from Sewage Treatment Plant by Biofilm Ecological Floating Bed].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {41}, number = {2}, pages = {809-814}, doi = {10.13227/j.hjkx.201905150}, pmid = {32608741}, issn = {0250-3301}, mesh = {*Biofilms ; Bioreactors ; Nitrogen/*isolation & purification ; *Sewage ; *Waste Disposal, Fluid ; Water ; *Water Purification ; }, abstract = {The purification characteristics of nitrogenous tail water were investigated using a biofilm ecological floating bed technology to study biofilm length, hydraulic retention time (HRT), and biofilm coverage area with the aim to explore the purification characteristics of biofilm on urban tail water. Results show that the removal rates of NH4[+]-N, NO3[-]-N, and TN were 90.82%, 62.7%, and 81.96%, respectively, at the half water depth to the suspended biofilm. The removal rate of NH4[+]-N was only 22.07%, and the concentration changes of NO3[-]-N and TN were not obvious throughout the whole water depth to the suspended biofilm. When the HRT was 6 days, the removal rates of NH4[+]-N and TN could reach 82.01% and 62.88%, respectively, whereas the lowest rates were 55.24% and 46.82%, respectively. When the HRT was 12 days, the removal rates of NH4[+]-N and TN reached up to 81.4% and 79.93%, respectively, whereas the lowest rates were 8.73% and 17.23%, respectively. In contrast, the nitrogen removal efficiency was high and stable when the HRT was 6 days. When the coverage area was 10%, the removal rate was decreased in one operation cycle. When the coverage area was 20%, the removal rate showed an upward trend. Under the conditions of 10% and 20% biofilm coverage area, the removal rates of TN were 62.88% and 71.09%, respectively.}, } @article {pmid32608190, year = {2020}, author = {Ho, MH and Hasturk, H and Young, DF and Xie, H}, title = {In vivo and ex vivo actions of a novel P. gingivalis inhibitor on multi-species biofilm, inflammatory response, and periodontal bone loss.}, journal = {Molecular oral microbiology}, volume = {35}, number = {5}, pages = {193-201}, pmid = {32608190}, issn = {2041-1014}, support = {R21 DE025332/DE/NIDCR NIH HHS/United States ; S21 MD000104/MD/NIMHD NIH HHS/United States ; U54 MD007593/MD/NIMHD NIH HHS/United States ; }, mesh = {*Alveolar Bone Loss/drug therapy ; Animals ; Biofilms/*drug effects ; Cells, Cultured ; *Chronic Periodontitis/drug therapy ; Cytokines/metabolism ; Humans ; Keratinocytes ; Mice ; Peptides/*pharmacology ; Porphyromonas gingivalis/*drug effects ; Virulence ; }, abstract = {Chronic periodontitis is one of the most common infectious inflammatory diseases worldwide. Current therapeutic options for the disease are only partially and temporarily successful due to periodontal re-emergence of pathogens such as Porphyromonas gingivalis, a keystone bacterium in the oral microbial communities, which elicits a dysbiosis between the microbiota and the host. Previously, we reported a peptide inhibitor of P. gingivalis (SAPP) that specifically targets P. gingivalis and reduces its virulence potential in vitro. Here, we show that SAPP can modulate the ability of P. gingivalis to suppress the host innate immune system. Using a cytokine array analysis, we found that the levels of several cytokines including IL-6, IL-8, and MCP-1 in the culture media of human oral keratinocytes (HOKs) were significantly diminished in the presence of P. gingivalis. Whereas the levels of these cytokines were restored, at least partially, in the culture media of HOKs by SAPP treatment. Furthermore, we also observed in an ex vivo assay that SAPP efficiently inhibited biofilm primed formation by mixed-species oral bacteria, and significantly dampened the abnormally innate immune responses induced by these bacteria. We also demonstrated, using a mouse model, that SAPP could prevent alveolar bone loss induced by P. gingivalis. Our results suggest that SAPP specifically targets P. gingivalis and its associated bacterial communities and could be envisioned as an emerging therapy for periodontitis.}, } @article {pmid32607723, year = {2020}, author = {Ueda, A and Ogasawara, S and Horiuchi, K}, title = {Identification of the genes controlling biofilm formation in the plant commensal Pseudomonas protegens Pf-5.}, journal = {Archives of microbiology}, volume = {202}, number = {9}, pages = {2453-2459}, doi = {10.1007/s00203-020-01966-0}, pmid = {32607723}, issn = {1432-072X}, support = {16KT0150//Japan Society for the Promotion of Science/ ; }, mesh = {Adhesins, Bacterial/genetics/metabolism ; Bacterial Proteins/*genetics ; *Biofilms ; Genes, Regulator ; Histidine Kinase/genetics ; Mutation ; Pseudomonas/*genetics ; }, abstract = {Determinant genes controlling biofilm formation in a plant commensal bacterium, Pseudomonas protegens Pf-5, were identified by transposon mutagenesis. Comprehensive screening of 7500 transposon-inserted mutants led to the isolation of four mutants exhibiting decreased and five mutants exhibiting increased biofilm formation. Mutations in the genes encoding MFS drug resistance transporter, LapA adhesive protein, RetS sensor histidine kinase/response regulator, and HecA adhesin/hemagglutinin led to decreased biofilm formation, indicating that these genes are necessary for biofilm formation in Pf-5. The mutants exhibiting increased biofilm formation had transposon insertions in the genes coding for an outer membrane protein, a GGDEF domain-containing protein, AraC transcriptional regulator, non-ribosomal peptide synthetase OfaB, and the intergenic region of a DNA-binding protein and the Aer aerotaxis receptor, suggesting that these genes are negative regulators of biofilm formation. Some of these mutants also showed altered swimming and swarming motilities, and a negative correlation between biofilm formation and swarming motility was observed. Thus, sessile-motile lifestyle is regulated by divergent regulatory genes in Pf-5.}, } @article {pmid32606995, year = {2020}, author = {Lamichhane, K and Adhikari, N and Bastola, A and Devkota, L and Bhandari, P and Dhungel, B and Thapa Shrestha, U and Adhikari, B and Banjara, MR and Rijal, KR and Ghimire, P}, title = {Biofilm-Producing Candida Species Causing Oropharyngeal Candidiasis in HIV Patients Attending Sukraraj Tropical and Infectious Diseases Hospital in Kathmandu, Nepal.}, journal = {HIV/AIDS (Auckland, N.Z.)}, volume = {12}, number = {}, pages = {211-220}, pmid = {32606995}, issn = {1179-1373}, abstract = {INTRODUCTION: Oropharyngeal candidiasis are the commonest fungal infections among HIV-positive patients. The main objective of this study was to explore biofilm-producing Candida species causing oropharyngeal infections among HIV patients attending Sukraraj Tropical and Infectious Diseases Hospital (STIDH) in Kathmandu, Nepal.

METHODS: Oropharyngeal swabs were collected from the HIV-positive patients between July and December 2019. A total of 174 oropharyngeal swabs were cultured on Sabouraud Dextrose Agar (SDA). All samples were inoculated on SDA slants supplemented with chloramphenicol and underwent incubation at 37°C for 24-48 hours. Any visible growth reported was processed for the identification of the species. Candida species were differentiated based on the growth and colour of the isolates on CHROM agar candida. Biofilm production in Candida species was determined by the microtiter plate method (MPM). Antifungal susceptibility testing was performed using the disc diffusion method.

RESULTS: Among 174 oropharyngeal samples, 23.6% (n=41/174) of them had oropharyngeal infections and 36.6% of the oropharyngeal infections (15/41) had CD4 T-lymphocytes count below 200 cells/mm[3] who were also active tobacco users (p<0.05). Among Candidial growth, 61% (25/41) were Candida albicans and 39% (16/41) were non-albicans. Of 41 Candida spp., 65% (27/41) were biofilm producers. An equal proportion of Candida albicans (4 isolates) and non-albicans (4 isolates) were strong biofilm producers. C. albicans isolates were sensitive towards clotrimazole (96%; 24/25) and fluconazole (92%; 23/25), whereas sensitivity towards ketoconazole was only 48% (12/25). Non-albicans Candida was highly sensitive to amphotericin-B (62.5%; 10/16) followed by clotrimazole (56.2%; 9/16). The biofilm-producing Candida isolates showed the highest resistivity (51.9%; 14/27) to ketoconazole and lowest (22.2%; 6/27) to clotrimazole.

CONCLUSION: Oropharyngeal candidiasis is a common opportunistic infection among HIV-infected individuals. The majority of cases of oropharyngeal candidiasis are caused by biofilm producers Candida albicans and non-albicans Candida. Biofilm producers Candida were more resistant towards commonly used antifungal drugs.}, } @article {pmid32606813, year = {2020}, author = {Kashef, MT and Saleh, NM and Assar, NH and Ramadan, MA}, title = {The Antimicrobial Activity of Ciprofloxacin-Loaded Niosomes against Ciprofloxacin-Resistant and Biofilm-Forming Staphylococcus aureus.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {1619-1629}, pmid = {32606813}, issn = {1178-6973}, abstract = {PURPOSE: The threat of Staphylococcus aureus antimicrobial resistance is increasing worldwide. Niosomes are a new drug delivery system that enhances the antimicrobial potential of antibiotics. We hereby aim to evaluate the antimicrobial and antibiofilm activity of ciprofloxacin-loaded niosomes.

METHODS: The antimicrobial susceptibility of clinical S. aureus isolates (n=59) was determined by Kirby-Bauer disk diffusion method. Their biofilm formation activity was tested by Christensen's method. Two ciprofloxacin-loaded niosomal formulations were prepared by thin-film hydration method, and their minimum inhibitory concentrations (MIC) were determined by agar dilution method, against ciprofloxacin-resistant and biofilm-forming isolates (n=24). Their ability to inhibit biofilm formation and eradicate already formed biofilms was evaluated and further confirmed by scanning electron microscope images. Non-synonymous mutations, in a quinolone resistance-determining regions of S. aureus isolates, were detected by polymerase chain reaction.

RESULTS: Most of the isolates were methicillin- (47/59) and ciprofloxacin-resistant (45/59). All except two isolates were capable of biofilm production. Niosomal preparation I reduced ciprofloxacin MIC by twofold in four isolates, whereas preparation II reduced ciprofloxacin MIC of most isolates by 8- to 32-fold, with three isolates that became ciprofloxacin-susceptible. Non-synonymous mutations were detected in isolates that maintained phenotypic ciprofloxacin resistance against ciprofloxacin-loaded niosomal preparation II. Ciprofloxacin-loaded niosomes reduced the minimum biofilm inhibitory concentration and the minimum biofilm eradication concentration in 58% and 62% of the tested isolates, respectively.

CONCLUSION: Ciprofloxacin-loaded niosomes can restore ciprofloxacin activity against resistant S. aureus isolates. To our knowledge, this is the first report on the inhibition of biofilm formation and eradication of formed biofilms by ciprofloxacin-loaded niosomes.}, } @article {pmid32604791, year = {2020}, author = {De Gregorio, E and Esposito, A and Vollaro, A and De Fenza, M and D'Alonzo, D and Migliaccio, A and Iula, VD and Zarrilli, R and Guaragna, A}, title = {N-Nonyloxypentyl-l-Deoxynojirimycin Inhibits Growth, Biofilm Formation and Virulence Factors Expression of Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {32604791}, issn = {2079-6382}, support = {PRIN2017 (Grant 2017SFBFER)//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; FFC #20/2019//Fondazione per la Ricerca sulla Fibrosi Cistica/ ; }, abstract = {Staphylococcus aureus is one of the major causes of hospital- and community-associated bacterial infections throughout the world, which are difficult to treat due to the rising number of drug-resistant strains. New molecules displaying potent activity against this bacterium are urgently needed. In this study, d- and l-deoxynojirimycin (DNJ) and a small library of their N-alkyl derivatives were screened against S. aureus ATCC 29213, with the aim to identify novel candidates with inhibitory potential. Among them, N-nonyloxypentyl-l-DNJ (l-NPDNJ) proved to be the most active compound against S. aureus ATCC 29213 and its clinical isolates, with the minimum inhibitory concentration (MIC) value of 128 μg/mL. l-NPDNJ also displayed an additive effect with gentamicin and oxacillin against the gentamicin- and methicillin-resistant S. aureus isolate 00717. Sub-MIC values of l-NPDNJ affected S. aureus biofilm development in a dose-dependent manner, inducing a strong reduction in biofilm biomass. Moreover, real-time reverse transcriptase PCR analysis revealed that l-NPDNJ effectively inhibited at sub-MIC values the transcription of the spa, hla, hlb and sea virulence genes, as well as the agrA and saeR response regulator genes.}, } @article {pmid32603591, year = {2020}, author = {Locke, LW and Shankaran, K and Gong, L and Stoodley, P and Vozar, SL and Cole, SL and Tweedle, MF and Wozniak, DJ}, title = {Evaluation of Peptide-Based Probes toward In Vivo Diagnostic Imaging of Bacterial Biofilm-Associated Infections.}, journal = {ACS infectious diseases}, volume = {6}, number = {8}, pages = {2086-2098}, pmid = {32603591}, issn = {2373-8227}, support = {R01 AI134895/AI/NIAID NIH HHS/United States ; R01 EB022134/EB/NIBIB NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; U24 CA180803/CA/NCI NIH HHS/United States ; }, mesh = {*Bacterial Infections ; *Biofilms ; Diagnostic Imaging ; Humans ; Peptides ; Pseudomonas aeruginosa ; }, abstract = {The clinical management of bacterial biofilm infections represents an enormous challenge in today's healthcare setting. The NIH estimates that 65% of bacterial infections are biofilm-related, and therapeutic outcomes are positively correlated with early intervention. Currently, there is no reliable imaging technique to detect biofilm infections in vivo, and current clinical protocols for accurate and direct biofilm identification are nonexistent. In orthopedic implant-associated biofilm infections, for example, current detection methods are based on nonspecific X-ray or radiolabeled white blood cell imaging, coupled with peri-prosthetic tissue or fluid samples taken invasively, and must be cultured. This approach is time-consuming and often fails to detect biofilm bacteria due to sampling errors and a lack of sensitivity. The ability to quantify bacterial biofilms by real-time noninvasive imaging is an urgent unmet clinical need that would revolutionize the management and treatment of these devastating types of infections. In the present study, we assembled a collection of fluorescently labeled peptide candidates to specifically explore their biofilm targeting properties. We evaluated these fluorescently labeled peptides using various in vitro assays for their ability to specifically and nondestructively target biofilms produced by model bacterial pathogen Pseudomonas aeruginosa. The lead candidate that emerged, 4Iphf-HN17, demonstrated rapid biofilm labeling kinetics, a lack of bactericidal activity, and biofilm targeting specificity in human cell infection models. In vivo fluorescently labeled 4Iphf-HN17 showed enhanced accumulation in biofilm-infected wounds, thus warranting further study.}, } @article {pmid32603487, year = {2020}, author = {Ohn, HM and Mizuno, T and Sudo, Y and Miyoshi, SI}, title = {Interaction of Escherichia coli and its culture supernatant with Vibrio vulnificus during biofilm formation.}, journal = {Microbiology and immunology}, volume = {64}, number = {9}, pages = {593-601}, doi = {10.1111/1348-0421.12829}, pmid = {32603487}, issn = {1348-0421}, support = {//Japan Agency for Medical Research and Development/ ; JP19fm0108002//Ministry of Education, Culture, Sports, Science and Technology/ ; }, mesh = {Biofilms/*growth & development ; *Culture Media, Conditioned ; Escherichia coli/*growth & development ; *Microbial Interactions ; Microbial Viability ; Vibrio vulnificus/*growth & development ; }, abstract = {Vibrio vulnificus is a foodborne pathogen causing septicemia with high mortality rate. In this study, we explored how Escherichia coli, one of the commensal bacteria in the human gastrointestinal tract, can interact with V. vulnificus. Our study results show that the amount of biofilm produced by V. vulnificus was reduced in the presence of E. coli ATCC 35218, although the growth of V. vulnificus L-180 remained unaffected. We also detected an antibiofilm effect of E. coli culture supernatant against V. vulnificus, which could not be reduced even after heat treatment. These findings indicate that E. coli and its culture supernatant may be suitable to prevent biofilm formation by V. vulnificus. By contrast, live cells of V. vulnificus could reduce the amount of preformed E. coli biofilm, but its culture supernatant could not. This suggests that the cell-associated factors contribute toward reduction in E. coli biofilm. Therefore, we speculate that ingestion of an infectious dose of V. vulnificus might induce dislodging of the commensal bacteria from the intestinal epithelia and thus can colonize to initiate the infection.}, } @article {pmid32601062, year = {2020}, author = {Marmont, LS and Whitfield, GB and Pfoh, R and Williams, RJ and Randall, TE and Ostaszewski, A and Razvi, E and Groves, RA and Robinson, H and Nitz, M and Parsek, MR and Lewis, IA and Whitney, JC and Harrison, JJ and Howell, PL}, title = {PelX is a UDP-N-acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {34}, pages = {11949-11962}, pmid = {32601062}, issn = {1083-351X}, support = {R01 AI143916/AI/NIAID NIH HHS/United States ; FDN154327//CIHR/Canada ; R01 AI077628/AI/NIAID NIH HHS/United States ; P30 EB009998/EB/NIBIB NIH HHS/United States ; MOP 43998//CIHR/Canada ; R01 AI134895/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Carbohydrate Epimerases/genetics/*metabolism ; Polysaccharides, Bacterial/genetics/*metabolism ; Pseudomonas/*physiology ; Pseudomonas aeruginosa/*physiology ; Uridine Diphosphate N-Acetylglucosamine/genetics/metabolism ; }, abstract = {Pel is a GalNAc-rich bacterial polysaccharide that contributes to the structure and function of Pseudomonas aeruginosa biofilms. The pelABCDEFG operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of pel gene clusters has helped us identify an additional gene, pelX, that is present adjacent to pelABCDEFG in >100 different bacterial species. The pelX gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pseudomonas protegens Pf-5 as a model to elucidate PelX function as Pseudomonas aeruginosa lacks a pelX homologue in its pel gene cluster. We found that P. protegens forms Pel-dependent biofilms; however, despite expression of pelX under these conditions, biofilm formation was unaffected in a ΔpelX strain. This observation led us to identify a pelX paralogue, PFL_5533, which we designate here PgnE, that appears to be functionally redundant to pelX In line with this, a ΔpelX ΔpgnE double mutant was substantially impaired in its ability to form Pel-dependent biofilms. To understand the molecular basis for this observation, we determined the structure of PelX to 2.1 Å resolution. The structure revealed that PelX resembles UDP-GlcNAc C4-epimerases. Using [1]H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Our results indicate that Pel-dependent biofilm formation requires a UDP-GlcNAc C4-epimerase that generates the UDP-GalNAc precursors required by the Pel synthase machinery for polymer production.}, } @article {pmid32600373, year = {2020}, author = {Thorarinsdottir, HR and Kander, T and Holmberg, A and Petronis, S and Klarin, B}, title = {Biofilm formation on three different endotracheal tubes: a prospective clinical trial.}, journal = {Critical care (London, England)}, volume = {24}, number = {1}, pages = {382}, pmid = {32600373}, issn = {1466-609X}, support = {2012-01252//VINNOVA/International ; 814201//Skåne County Council's Research and Development Foundation/International ; }, mesh = {Aged ; *Biofilms ; Body Mass Index ; Female ; Humans ; Intubation, Intratracheal/adverse effects/*instrumentation ; Male ; Middle Aged ; Prospective Studies ; Proton Pump Inhibitors/administration & dosage/therapeutic use ; Respiration, Artificial/*adverse effects/instrumentation/methods ; Simplified Acute Physiology Score ; Sweden ; }, abstract = {BACKGROUND: Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.

METHODS: We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.

RESULTS: High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14-15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06-0.59], p = 0.005, and OR 0.34 [95% CI 0.13-0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17-1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.

CONCLUSION: High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.

TRIAL REGISTRATION: ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.}, } @article {pmid32600259, year = {2020}, author = {Loimaranta, V and Mazurel, D and Deng, D and Söderling, E}, title = {Xylitol and erythritol inhibit real-time biofilm formation of Streptococcus mutans.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {184}, pmid = {32600259}, issn = {1471-2180}, support = {11-2520//Turku University Foundation/International ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Dielectric Spectroscopy/instrumentation ; Erythritol/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Viability/drug effects ; Polysaccharides, Bacterial/metabolism ; Streptococcus mutans/drug effects/*physiology ; Xylitol/*pharmacology ; }, abstract = {BACKGROUND: Regular consumption of xylitol decreases the number of cariogenic streptococci in dental plaque. In vitro biofilm models to study the mechanism of xylitol action have been set-up, but the obtained results are contradictory. Biofilm growth is a dynamic process with time-specific characteristics that may remain undetected in conventional end-point biofilm tests. In this study we used an impedance spectroscopy instrument, xCELLigence Real Time Cell Analyzer (RTCA), that allows label-free, non-invasive real-time monitoring of biofilm formation, to explore effects of xylitol on biofilm formation by Streptococcus mutans. Based on the obtained information of biofilm dynamics, we assessed the number of viable bacteria, the polysaccharide content, and the expression levels of selected genes involved in glucan-mediated biofilm formation in different biofilm stages. Xylitol inhibition was compared with that of erythritol; another polyol suggested to have a positive impact on oral health.

RESULTS: Our results showed that real-time monitoring provided new information of polyol-induced changes in S. mutans biofilm formation dynamics. The inhibitory effect of polyols was more pronounced in the early stages of biofilm formation but affected also the measured total amount of formed biofilm. Effects seen in the real-time biofilm assay were only partially explained by changes in CFU values and polysaccharide amounts in the biofilms. Both xylitol and erythritol inhibited real-time biofilm formation by all the nine tested S. mutans strains. Sensitivity of the strains to inhibition varied: some were more sensitive to xylitol and some to erythritol. Xylitol also modified the expression levels of gbpB, gtfB, gtfC and gtfD genes that are important in polysaccharide-mediated adherence of S. mutans.

CONCLUSION: The erythritol- and xylitol- induced inhibition of biofilm formation was only partly explained by decrease in the number of viable S. mutans cells or the amount of polysaccharides in the biofilm matrix, suggesting that in addition to reduced proliferation also the matrix composition and thereby the surface attachment quality of biofilm matrix may be altered by the polyols.}, } @article {pmid32600258, year = {2020}, author = {Katongole, P and Nalubega, F and Florence, NC and Asiimwe, B and Andia, I}, title = {Biofilm formation, antimicrobial susceptibility and virulence genes of Uropathogenic Escherichia coli isolated from clinical isolates in Uganda.}, journal = {BMC infectious diseases}, volume = {20}, number = {1}, pages = {453}, pmid = {32600258}, issn = {1471-2334}, support = {107743//African Academy of Sciences/ ; }, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*growth & development ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial/genetics ; Escherichia coli Infections/drug therapy/*epidemiology/microbiology ; Humans ; Microbial Sensitivity Tests ; Phenotype ; Polymerase Chain Reaction ; Prevalence ; Uganda/epidemiology ; Urinary Tract Infections/drug therapy/*epidemiology/microbiology ; Uropathogenic Escherichia coli/drug effects/*genetics/isolation & purification/*pathogenicity ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {INTRODUCTION: Uropathogenic E. coli is the leading cause of Urinary tract infections (UTIs), contributing to 80-90% of all community-acquired and 30-50% of all hospital-acquired UTIs. Biofilm forming Uropathogenic E. coli are associated with persistent and chronic inflammation leading to complicated and or recurrent UTIs. Biofilms provide an environment for poor antibiotic penetration and horizontal transfer of virulence genes which favors the development of Multidrug-resistant organisms (MDRO). Understanding biofilm formation and antimicrobial resistance determinants of Uropathogenic E. coli strains will provide insight into the development of treatment options for biofilm-associated UTIs. The aim of this study was to determine the biofilm forming capability, presence of virulence genes and antimicrobial susceptibility pattern of Uropathogenic E. coli isolates in Uganda.

METHODS: This was a cross-sectional study carried in the Clinical Microbiology and Molecular biology laboratories at the Department of Medical Microbiology, Makerere University College of Health Sciences. We randomly selected 200 Uropathogenic E. coli clinical isolates among the stored isolates collected between January 2018 and December 2018 that had significant bacteriuria (> 10[5] CFU). All isolates were subjected to biofilm detection using the Congo Red Agar method and Antimicrobial susceptibility testing was performed using the Kirby disk diffusion method. The isolates were later subjected PCR for the detection of Urovirulence genes namely; Pap, Fim, Sfa, Afa, Hly and Cnf, using commercially designed primers.

RESULTS: In this study, 62.5% (125/200) were positive biofilm formers and 78% (156/200) of these were multi-drug resistant (MDR). The isolates were most resistant to Trimethoprim sulphamethoxazole and Amoxicillin (93%) followed by gentamycin (87%) and the least was imipenem (0.5%). Fim was the most prevalent Urovirulence gene (53.5%) followed by Pap (21%), Sfa (13%), Afa (8%), Cnf (5.5%) and Hyl (0%).

CONCLUSIONS: We demonstrate a high prevalence of biofilm-forming Uropathogenic E. coli strains that are highly associated with the MDR phenotype. We recommend routine surveillance of antimicrobial resistance and biofilm formation to understand the antibiotics suitable in the management of biofilm-associated UTIs.}, } @article {pmid32599948, year = {2020}, author = {Balaure, PC and Grumezescu, AM}, title = {Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {10}, number = {6}, pages = {}, pmid = {32599948}, issn = {2079-4991}, abstract = {Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of "emergent properties", meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both "fouling-resistant" and "fouling release" strategies are addressed as well as their synergic combination in a single unique nanoplatform.}, } @article {pmid32599828, year = {2020}, author = {Hathroubi, S and Zerebinski, J and Clarke, A and Ottemann, KM}, title = {Helicobacter pylori Biofilm Confers Antibiotic Tolerance in Part via A Protein-Dependent Mechanism.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {32599828}, issn = {2079-6382}, support = {R01 AI116946/AI/NIAID NIH HHS/United States ; 1S10OD023528/NH/NIH HHS/United States ; RO1AI116946//National Institute of Allergy and Infectious Diseases/ ; }, abstract = {Helicobacter pylori, a WHO class I carcinogen, is one of the most successful human pathogens colonizing the stomach of over 4.4 billion of the world's population. Antibiotic therapy represents the best solution but poor response rates have hampered the elimination of H. pylori. A growing body of evidence suggests that H. pylori forms biofilms, but the role of this growth mode in infection remains elusive. Here, we demonstrate that H. pylori cells within a biofilm are tolerant to multiple antibiotics in a manner that depends partially on extracellular proteins. Biofilm-forming cells were tolerant to multiple antibiotics that target distinct pathways, including amoxicillin, clarithromycin, and tetracycline. Furthermore, this tolerance was significantly dampened following proteinase K treatment. These data suggest that H. pylori adapts its phenotype during biofilm growth resulting in decreased antibiotic susceptibility but this tolerance can be partially ameliorated by extracellular protease treatment.}, } @article {pmid32599404, year = {2020}, author = {Li, C and Gu, Z and Zhu, S and Liu, D}, title = {17β-Estradiol removal routes by moving bed biofilm reactors (MBBRs) under various C/N ratios.}, journal = {The Science of the total environment}, volume = {741}, number = {}, pages = {140381}, doi = {10.1016/j.scitotenv.2020.140381}, pmid = {32599404}, issn = {1879-1026}, mesh = {Ammonia ; Biofilms ; *Bioreactors ; Estradiol ; *Nitrification ; }, abstract = {This study evaluated the contribution of biotic and abiotic routes to the 17β-estradiol (E2) removal in moving bed biofilm reactors (MBBRs), and uncovered the interrelation between the E2 removal routes and biofilm characteristics, which was not researched in previous literature. Three MBBRs with different C/N ratios (0 for C/N0; 2 for C/N2; and 5 for C/N5) were operated in continuous mode. A 65-day degradation demonstrated that the MBBRs had high potential to remove E2 regardless of the C/N (E2 removal greater than 99% for all MBBRs; P > 0.05). Further batch tests showed that the E2 removal mainly resulted from heterotrophic activities for all MBBRs, accounting for approximately 85% for all MBBRs (P > 0.05), followed by nitrification (10-11%) and adsorption (4-5%). Importantly, lower adhesive force likely led to higher E2 adsorption onto biofilms. Besides, enhanced ammonia oxidizing rate (AOR) was consistent with the high contribution of nitrification to the E2 attenuation. Importantly, heterotrophic activity was positively correlated with its contribution to E2 removal (r = 0.99, P < 0.05). To sum, the results obtained in this study helped to understand the E2 removal routes in nitrifying biofilm systems.}, } @article {pmid32599380, year = {2020}, author = {Tang, K and Ooi, GTH and Torresi, E and Kaarsholm, KMS and Hambly, A and Sundmark, K and Lindholst, S and Sund, C and Kragelund, C and Christensson, M and Bester, K and Andersen, HR}, title = {Municipal wastewater treatment targeting pharmaceuticals by a pilot-scale hybrid attached biofilm and activated sludge system (Hybas™).}, journal = {Chemosphere}, volume = {259}, number = {}, pages = {127397}, doi = {10.1016/j.chemosphere.2020.127397}, pmid = {32599380}, issn = {1879-1298}, mesh = {Biofilms/growth & development ; Bioreactors ; Nitrification ; *Pharmaceutical Preparations ; Sewage/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater ; *Water Pollutants, Chemical ; }, abstract = {A hybrid wastewater treatment process with combined attached biofilm (moving bed biofilm reactor) and activated sludge, named as Hybas™, was implemented for the treatment of municipal wastewater. The system consisted of six staged reactors in series including pre-denitrification and nitrification in the Hybas™ line and post-denitrification in a pure MBBR. In addition to the significant removal of nutrients and organic matter from municipal wastewater, Hybas™ also showed removal capacity for pharmaceuticals. Of particular interest was the enhanced removal for pharmaceuticals (i.e. X-ray contrast media) compared to other biological systems. Spiking experiments showed that the maximum removal rate constants (k, h[-1]) for 10 out of the 21 investigated pharmaceuticals (including diclofenac) were observed to occur within the two aerobic Hybas ™ reactors, operated in a flow-shifting mode that allows even biofilm growth of nitrifying bacteria. In total, 14 out of the 21 pharmaceuticals were removed by more than 50% during continuous flow operation in the all Hybas™ line and post-denitrification MBBR. The calculated and estimated removal contributions of pharmaceuticals by each individual reactor were also assessed.}, } @article {pmid32598252, year = {2020}, author = {Ismail, NS and Subbiah, SK and Taib, NM}, title = {Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Pseudomonas aeruginosa from Clinical Isolates.}, journal = {Current pharmaceutical biotechnology}, volume = {21}, number = {14}, pages = {1539-1550}, doi = {10.2174/1389201021666200629145217}, pmid = {32598252}, issn = {1873-4316}, support = {FRGS 5524635//Fundamental Research Grant Scheme/ ; 9520900//UPM Putra/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; Carbon/*metabolism ; Environmental Microbiology ; Humans ; *Metabolome/drug effects ; Microarray Analysis ; Microbial Sensitivity Tests ; Phenotype ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/*growth & development/isolation & purification/metabolism ; }, abstract = {BACKGROUND: This is the fastest work in obtaining the metabolic profiles of Pseudomonas aeruginosa in order to combat the infection diseases which leads to high morbidity and mortality rates. Pseudomonas aeruginosa is a high versatility of gram-negative bacteria that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism and regulatory system, ensure the survival of this microorganism in the diverse environment condition. Determination of differences in carbon sources utilization among biofilm and non-biofilm of Pseudomonas aeruginosa provides a platform in understanding the metabolic activity of the microorganism.

METHODS: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog).

RESULTS AND DISCUSSION: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid.

CONCLUSION: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.}, } @article {pmid32596251, year = {2020}, author = {Pettersson, S and Ahnoff, M and Edin, F and Lingström, P and Simark Mattsson, C and Andersson-Hall, U}, title = {A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and Lower Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks.}, journal = {Frontiers in nutrition}, volume = {7}, number = {}, pages = {88}, pmid = {32596251}, issn = {2296-861X}, abstract = {The purpose of this study was to evaluate the substrate oxidation of three commercially available, 14%-carbohydrate sports drinks with different compositions, osmolality, and pH for their impact on dental exposure to low pH. In a cross-over, randomized double-blinded design, 12 endurance athletes (age 31. 2 ± 7.7 years, V ˙ O2max 65.6 ± 5.0 mL·kg[-1]) completed 180 min of cycling at 55% Wmax. During the first 100 min of cycling, athletes consumed amylopectin starch (AP), maltodextrin+sucrose (MD+SUC), or maltodextrin+fructose hydrogel (MD+FRU) drinks providing 95 g carbohydrate·h[-1], followed by water intake only at 120 and 160 min. Fuel use was determined using indirect calorimetry and stable-isotope techniques. Additionally, dental biofilm pH was measured using the microtouch method in a subsample of participants (n = 6) during resting conditions before, and at different time intervals up to 45 min following a single bolus of drink. Exogenous carbohydrate oxidation (CHOEXO) during the 2nd hour of exercise was significantly (P < 0.05) different between all three drinks: MD+FRU (1.17 ± 0.17 g·min[-1]), MD+SUC (1.01 ± 0.13 g·min[-1]), and AP (0.84 ± 0.11 g·min[-1]). At the end of exercise, CHOEXO and blood glucose concentrations (3.54 ± 0.50, 4.07 ± 0.67, and 4.28 ± 0.47 mmol·L[-1], respectively) were significantly lower post MD+FRU consumption than post MD+SUC and AP consumption (P < 0.05). Biofilm acidogenicity at rest demonstrated a less pronounced pH fall for MD+FRU compared to the acidulant-containing MD+SUC and AP (P < 0.05). In conclusion, while total intake of MD+FRU showed signs of completed uptake before end of monitoring, this was less so for MD+SUC, and not at all the case for AP. Thus, this study showed that despite carbohydrates being encapsulated in a hydrogel, a higher CHOEXO was observed following MD+FRU drink ingestion compared to AP and MD+SUC consumption upon exposure to the acidic environment of the stomach. This finding may be related to the higher fructose content of the MD+FRU drink compared with the MD+SUC and AP drinks. Furthermore, a carbohydrate solution without added acidulants, which are commonly included in commercial sport drinks, may have less deleterious effects on oral health.}, } @article {pmid32596125, year = {2020}, author = {Hu, D and Zou, L and Yu, W and Jia, F and Han, H and Yao, K and Jin, Q and Ji, J}, title = {Relief of Biofilm Hypoxia Using an Oxygen Nanocarrier: A New Paradigm for Enhanced Antibiotic Therapy.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {7}, number = {12}, pages = {2000398}, pmid = {32596125}, issn = {2198-3844}, abstract = {Biofilms are chief culprits of most intractable infections and pose great threats to human health. Conventional antibiotic therapies are hypodynamic to biofilms due to their strong drug resistance, closely related with biofilm hypoxia. A new strategy for enhanced antibiotic therapy by relieving biofilm hypoxia is reported here. A two-step sequential delivery strategy is fabricated using perfluorohexane (PFH)-loaded liposomes (lip) as oxygen (O2) carriers (denoted as lip@PFH@O2) and commercial antibiotics. The results indicate that the two-step sequential treatment exhibits much lower minimum bactericidal concentrations than the antibiotic treatment alone. In this design, the lip@PFH@O2 holds positively charged surface for better biofilm penetration. After penetrating into biofilm, oxygen can be released from lip@PFH@O2 by inches, which greatly relieves biofilm hypoxia. With the relief of hypoxia, the quorum sensing and the drug efflux pumps of bacteria are suppressed by restraining related gene expression, leading to the reduced antibiotic resistance. Furthermore, the in vivo experimental results also demonstrate that lip@PFH@O2 can effectively relieve biofilm hypoxia and enhance therapeutic efficacy of antibiotics. As a proof-of-concept, this research provides an innovative strategy for enhanced antibiotic therapy by relieving hypoxia, which may hold a bright future in combating biofilm-associated infections.}, } @article {pmid32596100, year = {2020}, author = {Hakimi Alni, R and Ghorban, K and Dadmanesh, M}, title = {Combined effects of Allium sativum and Cuminum cyminum essential oils on planktonic and biofilm forms of Salmonella typhimurium isolates.}, journal = {3 Biotech}, volume = {10}, number = {7}, pages = {315}, pmid = {32596100}, issn = {2190-572X}, abstract = {Sa lmonella typhimurium (S. typhimurium) represents an important global public health problem and has the ability to survive under desiccation conditions in foods and food processing facilities for years. The aim of this study was to investigate the effects of Allium sativum (A. sativum) and Cuminum cyminum (C. cyminum) essential oils (EOs) against planktonic growth, biofilm formation and quorum sensing (QS) of S. Typhimurium isolates, the strong biofilm producers. The major components of EOs were determined by gas chromatography-mass spectrometry (GC-MS). Biofilm formation of S. Typhimurium isolates was measured by crystal violet staining. Then, the effects of the EOs on the planktonic cell growth (using determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)), measurement of the synergistic effects of EOs (using checkerboard method), biofilm formation (using microtiter-plate test and scanning electron microscope (SEM)), and expression of QS and cellulose synthesis genes (using quantitative real-time PCR) were assessed. Finally, tetrazolium-based colorimetric (MTT) assay was used to examine EOs cytotoxicity on the Vero cell line. GC-MS analysis showed that terpineol, carene and pinene in C. cyminum EO and sulfur compounds in A. sativum EO were the major components of the plant extract. The Geometric mean of MIC values of the A. sativum and C. cyminum were 0.66 and 2.62 μL mL[-1], respectively. The geometric means of the fractional inhibitory concentration index (FICi) for both EOs were calculated as 1.05. The qPCR results showed that MIC/2 concentrations of both EOs significantly down-regulated of QS (sdiA and luxS) and cellulose synthesis (csgD and adrA) genes. Scanning electron microscopy showed the EOs reduced the amount of S. Typhimurium mature biofilm. In general, we showed that C. cyminum and A. sativum EOs can be considered as the potential agents against planktonic and biofilm form of S. Typhimurium without any concern of cytotoxic effect at 4 MIC concentrations on the eukaryotic Vero cells.}, } @article {pmid32595625, year = {2020}, author = {Cui, P and Feng, L and Zhang, L and He, J and An, T and Fu, X and Li, C and Zhao, X and Zhai, Y and Li, H and Yan, W and Li, H and Luo, X and Lei, C and Wang, H and Yang, X}, title = {Antimicrobial Resistance, Virulence Genes, and Biofilm Formation Capacity Among Enterococcus species From Yaks in Aba Tibetan Autonomous Prefecture, China.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1250}, pmid = {32595625}, issn = {1664-302X}, abstract = {Yaks provide necessities such as meat and milk for Tibetans living at high altitudes on and around the Qinghai-Tibetan Plateau. Enterococci are ubiquitous members of the animal gut microbiota that can cause biofilm-associated opportunistic infections. Meanwhile, multidrug-resistant Enterococcus also poses a serious threat to public health. This study aims to characterize antibiotic resistance, virulence genes, and biofilm formation of enterococci from yaks. From April 2018 to July 2019, we collected 395 fecal samples of yaks in Aba Tibetan Autonomous Prefecture, China. Enterococci isolated from the samples were identified and classified according to the 16S rDNA sequence. The antibiotic resistance of each isolate was detected according to the Kirby-Bauer disk diffusion method, and antibiotic resistance genes were detected by polymerase chain reaction (PCR) and sequencing. Enterococcal biofilms were assessed using standard procedures. Different virulence genes were detected by PCR and sequencing. In total, 381 enterococci strains were recovered, with Enterococcus faecalis (41.99%) and Enterococcus faecium (37.80%) being the predominant species. Many isolates were multidrug- resistant (60.37%) and showed a high resistance rate to rifampicin (64.30%) and tetracycline (61.54%). We also detected various antimicrobial resistance (AMR) genes in the tested strains. The E. faecalis strains had higher frequency of biofilm formation and virulence genes than other enterococcal species. This is the first report that shows yaks are repositories for drug-resistant enterococci with virulent determinants and biofilms that may spread into humans and to environment. This study also provides useful data suggesting that enterococci may pose a potential health risk to yaks. Therefore, active surveillance of AMR and pathogenesis in enterococci from yaks is urgently warranted.}, } @article {pmid32595199, year = {2020}, author = {Cherdvorapong, V and Panti, N and Suyotha, W and Tsuchiya, Y and Toyotake, Y and Yano, S and Wakayama, M}, title = {Prevention of oral biofilm formation and degradation of biofilm by recombinant α-1,3-glucanases from Streptomyces thermodiastaticus HF3-3.}, journal = {The Journal of general and applied microbiology}, volume = {66}, number = {5}, pages = {256-264}, doi = {10.2323/jgam.2019.11.003}, pmid = {32595199}, issn = {1349-8037}, mesh = {Bacterial Proteins/genetics/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Escherichia coli/genetics/metabolism ; Glycoside Hydrolases/genetics/metabolism/*pharmacology ; Hydrogen-Ion Concentration ; Recombinant Proteins/metabolism/pharmacology ; Streptococcus mutans/drug effects/growth & development/metabolism ; Streptomyces/*enzymology/genetics ; Temperature ; Toothpastes/chemistry ; }, abstract = {The genes encoding α-1,3-glucanases (Agls; AglST1 and AglST2) from Streptomyces thermodiastaticus HF3-3 were cloned and were then expressed in Escherichia coli Rosetta-gami B (DE3). We purified the resultant histidine (His)-tagged α-1,3-glucanases (recombinant enzymes, rAglST1 and rAglST2). Both the recombinant enzymes were similar to the wild-type enzymes. We examined the effects of rAglST1 and rAglST2 on the formation and degradation of biofilms on glass plates with Streptococcus mutans NRBC 13955 by evaluating the biofilm content (%), release of reducing sugar (mM), release of S. mutans (log CFU/mL), and the biofilm structure using laser scanning microscopy (LSM). The results showed that after incubation for 16 h, rAglST1 and rAglST2 reduced the formation of biofilm to 52% and 49% of the control, respectively. The result may reflect the fact that the concentration of the reducing sugar and the number of S. mutans cells in the rAglATs-added medium were higher than in the control medium. After an 8-h treatment with rAglST1 and rAglST2, biofilms decreased to less than 60% of the control. The number of S. mutans cells in the reaction mixture gradually increased during the incubation period. The enzymes can degrade the biofilms that were pre-formed on the glass plate by more than 50% after a 30-min incubation in the presence of toothpaste ingredients (1% w/v of sodium fluoride, benzethonium chloride, and sodium dodecyl sulfate) at 50°C. Our study showed that rAglST1 and rAglST2 have advantageous properties for dental care applications.}, } @article {pmid32594845, year = {2020}, author = {Huang, C and Liu, LZ and Kong, HK and Law, COK and Hoa, PQ and Ho, PL and Lau, TCK}, title = {A novel incompatibility group X3 plasmid carrying blaNDM-1 encodes a small RNA that regulates host fucose metabolism and biofilm formation.}, journal = {RNA biology}, volume = {17}, number = {12}, pages = {1767-1776}, pmid = {32594845}, issn = {1555-8584}, mesh = {Biofilms/*growth & development ; Carbohydrate Metabolism/drug effects ; Computational Biology/methods ; Escherichia coli/drug effects/*genetics/growth & development/*metabolism ; Fucose/*metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; High-Throughput Nucleotide Sequencing ; Humans ; Microbial Sensitivity Tests ; Plasmids/*genetics ; *RNA, Bacterial ; Transcriptome ; beta-Lactamases/*genetics ; }, abstract = {The emergence of New Delhi metallo-beta-lactamase (NDM-1) has become a major health threat to clinical managements of gram-negative bacteria infections. A novel incompatibility group X3 plasmid (IncX3) pNDM-HN380 carrying blaNDM-1 has recently been found to epidemiologically link with multiple geographical areas in China. In this paper, we studied the metabolic responses of host bacteria E. coli J53 upon introduction of pNDM-HN380. A reduction of bacterial motility was observed in J53/pNDM-HN380. We profiled the RNA repertoires of the transconjugants and found a downregulation of genes involved in flagella and chemotaxis metabolic pathways at logarithmic (log) phase. We also identified a novel intragenic region (IGR) small RNA plas2. The plasmid-transcribed sRNA IGR plas2 was further characterized as a regulator of fucRwhich controls the fucose metabolism. By knockdown of IGR plas2 using an antisense decoy, we managed to inhibit the formation of bacterial biofilm of the host. Our study demonstrated a potential way of utilizing plasmid-transcribed sRNA against infectious bacteria.}, } @article {pmid32594432, year = {2020}, author = {Zeng, M and Yang, J and Wu, Z and Wang, W and Xu, L and Wu, N and Wang, C}, title = {Achieving single-stage autotrophic nitrogen removal by composite membrane aerated biofilm with gel under two microbial entrapping patterns: experimental and modeling aspects.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {28}, pages = {35381-35391}, pmid = {32594432}, issn = {1614-7499}, support = {21607114//National Natural Science Foundation of China/ ; 201901260//Tianjin Agricultrual Commission Program/ ; 2019YJSS035//Postgraduate research and innovation project of Tianjin/ ; }, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; *Nitrogen ; Oxidation-Reduction ; Wastewater ; }, abstract = {Single-stage autotrophic nitrogen removal offers advantages of low energy and carbon consumptions. Based on previous work about a novel composite membrane aerated biofilm (CMAB), two microbial entrapping patterns (mixed and stratified patterns) were evaluated for their applicability to artificially regulate the spatial distribution of distinct microbial aggregates for single-stage autotrophic nitrogen removal. Experimental results showed that the stratified pattern caused little accumulation of NO2[-] and NO3[-], which leads to a superior nitrogen removal performance compared with the mixed pattern. Candidatus Kuenenia was found to be the major anammox bacterium in the gel film of the mixed pattern and the outer film of the stratified pattern. In contrast, Nitrosomonas, as a representative genus of ammonia-oxidizing bacteria, was substantially enriched in the inner film of the stratified pattern and the gel film of the mixed pattern. Finally, modeling results further confirmed the advantages of the stratified pattern with respect to the formation of rational microbial and nutrient profiles in gel films. The ratio of partial nitrification and anammox film thicknesses should remain below 3:2 to obtain a high fraction of anammox bacteria and to avoid NO2[-] accumulation. Increasing O2 surface loading does not affect microbial profiles, but can greatly promote the TN removal performance only in the stratified pattern. Overall, the stratified pattern should be employed to achieve optimal microbial profiles and nitrogen removal efficiency.}, } @article {pmid32593786, year = {2020}, author = {Gao, L and Han, F and Zhang, X and Liu, B and Fan, D and Sun, X and Zhang, Y and Yan, L and Wei, D}, title = {Simultaneous nitrate and dissolved organic matter removal from wastewater treatment plant effluent in a solid-phase denitrification biofilm reactor.}, journal = {Bioresource technology}, volume = {314}, number = {}, pages = {123714}, doi = {10.1016/j.biortech.2020.123714}, pmid = {32593786}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrates ; Nitrogen ; *Wastewater ; }, abstract = {In the present study, an up-flow solid-phase denitrification biofilm reactor (US-DBR) was established for simultaneous nitrate and dissolved organic matter (DOM) removal from wastewater treatment plant effluent. After 100 days operation, the nitrate and COD removal efficiencies were high of 97% and 80%, respectively. According to EEM-FRI analysis, aromatic and tryptophan protein-like, humic-like and fulvic acid-like substances were identified in DOM. Additionally, protein-like substances in DOM components were much easier transformed as carbon source for denitrification. Moreover, protein secondary structure of DOM changed significantly due to the biodegradation and microorganisms metabolic process. High-throughput sequencing analysis implied that Simplicispira, Diaphorobacter, Hydrogenophaga, Pseudoxanthmonas and Stenotrophomonas were the dominate genera in the whole of US-DBR, that were responsible for the removal of nitrate, organics and degradation of solid carbon source, respectively. This study provided a further biological basis about practical application of solid-phase denitrification for simultaneously remove nitrate and organic matter.}, } @article {pmid32593705, year = {2020}, author = {Sorkhdini, P and Gregory, RL and Crystal, YO and Tang, Q and Lippert, F}, title = {Effectiveness of in vitro primary coronal caries prevention with silver diamine fluoride - Chemical vs biofilm models.}, journal = {Journal of dentistry}, volume = {99}, number = {}, pages = {103418}, doi = {10.1016/j.jdent.2020.103418}, pmid = {32593705}, issn = {1879-176X}, mesh = {Biofilms ; Cariostatic Agents ; *Dental Caries/prevention & control ; Fluorides, Topical ; Humans ; Quaternary Ammonium Compounds/pharmacology ; Silver Compounds ; *Tooth Demineralization/prevention & control ; }, abstract = {OBJECTIVES: The main goal of this study was to investigate the effectiveness of SDF and its individual components, silver (Ag[+]) and fluoride (F[-]) ions, in preventing enamel demineralization using biofilm and chemical models.

METHODES: Polished human enamel specimens were assigned to five treatment groups (n = 18 per group): SDF (38 %); SDF followed by application of a saturated solution of potassium iodide (SDF + KI); silver nitrate (AgNO3; silver control, 253,900 ppm Ag[+]); potassium fluoride (KF; fluoride control, 44,800 ppm F); deionized water (DIW). Treatments were applied once to sound enamel. In the biofilm model, specimens were demineralized by aerobic overnight incubation using cariogenic bacteria isolated from human saliva in brain heart infusion supplemented with 0.2 % sucrose for three days. In the chemical model, enamel specimens were immersed in a demineralizing solution containing 0.1 M lactic acid, 4.1 mM CaCl2, 8.0 mM KH2PO4, 0.2 % Carbopol 907, pH adjusted to 5.0 for five days. Vickers surface microhardness was used to determine the extent of enamel demineralization. Data were analyzed using one-way ANOVA.

RESULTS: In the chemical model, there was no statistically significant difference between SDF and SDF + KI in preventing coronal caries (p < 0.0001). In the biofilm model, SDF + KI was significantly less effective in preventing demineralization than SDF (p < 0.0001). In both models, SDF and SDF + KI were superior in their ability to prevent caries lesion formation than AgNO3 and DIW.

CONCLUSION: KI application after SDF treatment appears to impair SDF's ability to prevent biofilm-mediated but not chemically induced demineralization.

CLINICAL SIGNIFICANCE: SDF may be a viable option in preventing primary coronal caries.}, } @article {pmid32593105, year = {2020}, author = {Xiang, Y and Shao, Z and Chai, H and Ji, F and He, Q}, title = {Functional microorganisms and enzymes related nitrogen cycle in the biofilm performing simultaneous nitrification and denitrification.}, journal = {Bioresource technology}, volume = {314}, number = {}, pages = {123697}, doi = {10.1016/j.biortech.2020.123697}, pmid = {32593105}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Nitrification ; Nitrogen ; Phylogeny ; }, abstract = {Simultaneous nitrification and denitrification (SND) is a potential energy-saving process in wastewater treatment while the nitrogen removal mechanism is still unclear due to the lack of information about the functional microbes and enzymes. Sequencing batch biofilm reactors were implemented to achieve efficient SND. Eight nitrogen removal related microorganisms out of the top abundant 20 microbial community and reference species were used to construct a phylogenetic tree. Functional enzymes and modules analysis were investigated to reveal the SND pathway: in the aerobic part of the biofilm, ammonia oxidation was catalyzed by complete ammonia oxidizers while in the inner anoxic part, denitrification, dissimilatory nitrate reduction (DNRA) and nitrogen fixation (NF) cooperated to stimulate nitrate removal. These results provide a practical aeration control strategy to achieve SND and indicate that DNRA and NF are important nitrogen removal pathways that should not be ignored in the SND mechanism.}, } @article {pmid32592930, year = {2020}, author = {Kato, K and Tamura, K and Shimazaki, Y}, title = {Oral biofilm uptake of mineral ions released from experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104777}, doi = {10.1016/j.archoralbio.2020.104777}, pmid = {32592930}, issn = {1879-1506}, mesh = {*Biofilms ; Dental Enamel ; *Dental Plaque/drug therapy ; Fluorides/*metabolism ; Glass Ionomer Cements/*chemistry ; Humans ; Minerals/*metabolism ; Toothpastes/*chemistry ; }, abstract = {OBJECTIVE: To clarify the fluoride/mineral kinetics in an oral biofilm following concurrent application of fluoride and other mineral ions released from experimental toothpaste containing S-PRG filler using depth-specific analysis.

STUDY DESIGN: Twenty subjects wore in situ plaque-generating devices, comprised of a pair of enamel slabs, and a biofilm was allowed to form. The devices were removed after three days, immersed in the toothpaste filtrate containing Al, B, Sr and F ions for 1 min, and then reinserted at the same location. After 30 min, the devices were removed and samples were obtained by sectioning into outer, middle and inner biofilm layers (300-μm thick). Samples treated with filtrate containing F without S-PRG filler extract served as the control. Fluoride and the three other mineral ions extracted from 4-μm sections were quantified using a fluoride electrode and ICP-AES, respectively. The results were corrected for biomass volume, estimated by the area measurement of stained 2-μm sections.

RESULTS: The mean uptake ratios (S-PRG/control, ng/mm[3]) of Al, B, Sr and F were 186.6/53.7, 58.4/25.0, 456.9/125.7 and 43.6/12.0, respectively, in the outer layer, indicating that the mineral ions could easily diffuse into the biofilm. F concentrations in the outer biofilm treated using filtrate with S-PRG filler extract were significantly higher than those in controls, although both biofilms were exposed to filtrates containing the same level of F.

CONCLUSIONS: The results suggest that toothpaste containing S-PRG filler promotes fluoride retention in oral biofilms via the uptake of other mineral ions.}, } @article {pmid32592827, year = {2020}, author = {Braga, AS and Simas, LLM and Pires, JG and Souza, BM and de Melo, FPSR and Saldanha, LL and Dokkedal, AL and Magalhães, AC}, title = {Antibiofilm and anti-caries effects of an experimental mouth rinse containing Matricaria chamomilla L. extract under microcosm biofilm on enamel.}, journal = {Journal of dentistry}, volume = {99}, number = {}, pages = {103415}, doi = {10.1016/j.jdent.2020.103415}, pmid = {32592827}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cariostatic Agents ; Cattle ; Chlorhexidine/pharmacology ; *Dental Caries ; Dental Enamel ; Humans ; *Matricaria ; Mouthwashes/pharmacology ; Streptococcus mutans ; *Tooth Demineralization ; }, abstract = {OBJECTIVE: This study evaluated the antibiofilm and anti-caries effects of an experimental mouth rinse containing aqueous extract of Matricaria chamomilla L.

METHODS: Microcosm biofilm was produced on bovine enamel, from pooled human saliva mixed with McBain saliva, under 0.2 % sucrose exposure, for 5 days. The biofilm was daily treated using (1 mL/1 min): Vochysia tucanorum Mart. (2.5 mg/mL); Myrcia bella Cambess. (1.25 mg/mL); Matricaria chamomilla L. (20 mg/mL); Malva sylvestris (Malvatricin® Plus-Daudt); 0.12 % Chlorhexidine (PerioGard®-Palmolive, Positive control) and PBS (Negative control). The % dead bacteria, biofilm thickness, EPS biovolume, lactic acid concentration, the CFU counting (total microorganisms, Lactobacillus sp., total streptococci and Streptococcus mutans/S. sobrinus) were determined. Enamel demineralization was measured by TMR.

RESULTS: All mouth rinses induced bacterial death compared to PBS (p < 0.0001). The biofilm thickness varied from 12 ± 2 μm (chlorhexidine) to 18 ± 2 μm (V. tucanorum) (ANOVA/Tukey, p < 0.0001). The EPS biovolume varied from 7(4)% (chlorhexidine) to 30(20)% (PBS) (Kruskal-Wallis/Dunn, p < 0.0001). The lactic acid production was reduced by M. sylvestris (1.1 ± 0.2 g/L) and chlorhexidine (0.6 ± 0.2 g/L) compared to PBS (2.6 ± 1.3 g/L) (ANOVA, p < 0.0001). Malva sylvestris and chlorhexidine showed significant low CFU for total microorganisms, Lactobacillus sp. and total streptococci. Only chlorhexidine significantly reduced S. mutans/S. sobrinus. CFUs for total streptococci and Lactobacillus sp, were also significantly reduced by M. chamomilla L. Malva sylvestris (63.4 % of mineral loss reduction), chlorhexidine (47.4 %) and M. chamomilla L. (39.4 %) significantly reduced enamel demineralization compared to PBS (ANOVA/Tukey, p < 0.0001).

CONCLUSION: M. chamomilla L. has lower antibiofilm action, but comparable anti-caries effect to those found for chlorhexidine, under this model.

CLINICAL RELEVANCE: This study shows that the antibiofilm and anti-caries potential may vary between the commercial and experimental mouth rinses containing natural agents, with promising results for those containing Matricaria chamomilla L. and Malva Sylvestris.}, } @article {pmid32590200, year = {2020}, author = {Koşarsoy Ağçeli, G and Cihangir, N}, title = {Nano-sized biopolymer levan: Its antimicrobial, anti-biofilm and anti-cancer effects.}, journal = {Carbohydrate research}, volume = {494}, number = {}, pages = {108068}, doi = {10.1016/j.carres.2020.108068}, pmid = {32590200}, issn = {1873-426X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Antineoplastic Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Biopolymers/chemistry/*pharmacology ; Cell Proliferation/drug effects ; Drug Screening Assays, Antitumor ; Fructans/chemistry/*pharmacology ; Humans ; MCF-7 Cells ; Nanoparticles/*chemistry ; Tumor Cells, Cultured ; }, abstract = {Among other polysaccharides, levan is a fructan with great potential in biotechnological applications due to its functional properties. The levan has only been available in small quantities because of its high cost. Here, a levan-producing microorganism was isolated from soil and identified as Pseudomonas mandelii. TGA, SEM, FTIR, [1]H NMR, [13]C NMR and Zetasizer analyses were used to characterize thermal properties and the morphology of the levan. It is the first time, the levan synthesized from P. mandelii is reported as nano sized. The culture conditions were optimized. It is the most comprehensive optimization study regarding levan production of P. mandelii up to the present. The optimum conditions found for levan production were 37 °C, at pH 8, under static conditions, with 15% sucrose and 1.5% mannitol as the C sources and yeast extract as the N source. In addition, the levan production yield was calculated at optimum conditions. Antibacterial activity of levan was evaluated against bacteria and the largest zone of inhibition was observed against E. coli at a concentration of 1000 μg/mL. Antibiofilm activity of levan was evaluated, and we found that all levan concentrations inhibited biofilm formation of all microorganisms in the study. We have shown that the levan from Pseudomonas mandelii induce cytotoxicity breast (MCF-7) cells in a dose-dependent manner.}, } @article {pmid32589289, year = {2020}, author = {Wang, S and Breslawec, AP and Li, C and Poulin, MB}, title = {A Colorimetric Assay to Enable High-Throughput Identification of Biofilm Exopolysaccharide-Hydrolyzing Enzymes.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {26}, number = {47}, pages = {10719-10723}, doi = {10.1002/chem.202002475}, pmid = {32589289}, issn = {1521-3765}, mesh = {Acetylglucosamine/metabolism ; *Biofilms ; *Colorimetry ; Escherichia coli/growth & development/metabolism ; Glycoside Hydrolases/*analysis/*metabolism ; }, abstract = {Glycosidase enzymes that hydrolyze the biofilm exopolysaccharide poly-β-(1→6)-N-acetylglucosamine (PNAG) are critical tools to study biofilm and potential therapeutic biofilm dispersal agents. Function-driven metagenomic screening is a powerful approach for the discovery of new glycosidase but requires sensitive assays capable of distinguishing between the desired enzyme and functionally related enzymes. Herein, we report the synthesis of a colorimetric PNAG disaccharide analogue whose hydrolysis by PNAG glycosidases results in production of para-nitroaniline that can be continuously monitored at 410 nm. The assay is specific for enzymes capable of hydrolyzing PNAG and not related β-hexosaminidase enzymes with alternative glycosidic linkage specificities. This analogue enabled development of a continuous colorimetric assay for detection of PNAG hydrolyzing enzyme activity in crude E. coli cell lysates and suggests that this disaccharide probe will be critical for establishing the functional screening of metagenomic DNA libraries.}, } @article {pmid32588628, year = {2020}, author = {Kang, J and Liu, L and Liu, Y and Wang, X}, title = {Ferulic Acid Inactivates Shigella flexneri through Cell Membrane Destructieon, Biofilm Retardation, and Altered Gene Expression.}, journal = {Journal of agricultural and food chemistry}, volume = {68}, number = {27}, pages = {7121-7131}, doi = {10.1021/acs.jafc.0c01901}, pmid = {32588628}, issn = {1520-5118}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Cell Membrane/*drug effects/genetics/metabolism ; Coumaric Acids/*pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Shigella flexneri/*drug effects/genetics/physiology ; }, abstract = {Antibiotic resistance and capacity for biofilm formation of Shigella flexneri render previous prevention and control strategies minimally effective. Ferulic acid (FA) has been demonstrated to be useful due to its application in foods as an alternative natural preservative. However, information regarding the S. flexneri phenotype and molecular responses to FA exposure is limited. The present study investigated the effects of FA on S. flexneri planktonic growth and biofilm formation. The results demonstrated that the cell membrane of S. flexneri in planktonic growth mode exhibited irreversible destruction after FA exposure, as characterized by decreased cell viability, leakage of cytoplasmic constituents, accelerated adenosine triphosphate (ATP) consumption, cell membrane depolarization, and cellular morphological changes. FA significantly inhibited S. flexneri adhesion and biofilm formation at a working concentration (1/8 MIC) that almost did not inhibit planktonic growth. Transcriptomics profiling showed that the exposure to a subinhibitory concentration of FA dramatically altered gene expression in the S. flexneri biofilm, as a total of 169 differentially expressed genes (DEGs) were upregulated and 533 DEGs were downregulated, compared to the intact biofilm. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the DEGs were mainly involved in pathways of ribosomes, ABC transporters, and the citrate cycle. Furthermore, we show that FA altered the transcription of S. flexneri genes associated with adhesion, transcriptional regulation, and the synthesis and transport of extracellular polymeric substances that contribute to biofilm formation. These data provide novel insights into S. flexneri behavioral responses to FA exposure and suggest that FA could effectively constrain S. flexneri and its biofilm formation.}, } @article {pmid32588553, year = {2020}, author = {Parlak, O and Richter-Dahlfors, A}, title = {Bacterial Sensing and Biofilm Monitoring for Infection Diagnostics.}, journal = {Macromolecular bioscience}, volume = {20}, number = {11}, pages = {e2000129}, doi = {10.1002/mabi.202000129}, pmid = {32588553}, issn = {1616-5195}, mesh = {Bacteria/*metabolism ; Bacterial Infections/*diagnosis ; *Biofilms ; Biosensing Techniques/*methods ; Electrochemistry ; Molecularly Imprinted Polymers/chemistry ; }, abstract = {Recent insights into the rapidly emerging field of bacterial sensing and biofilm monitoring for infection diagnostics are discussed as well as recent key developments and emerging technologies in the field. Electrochemical sensing of bacteria and bacterial biofilm via synthetic, natural, and engineered recognition, as well as direct redox-sensing approaches via algorithm-based optical sensing, and tailor-made optotracing technology are discussed. These technologies are highlighted to answer the very critical question: "how can fast and accurate bacterial sensing and biofilm monitoring be achieved? Following on from that: "how can these different sensing concepts be translated for use in infection diagnostics? A central obstacle to this transformation is the absence of direct and fast analysis methods that provide high-throughput results and bio-interfaces that can control and regulate the means of communication between biological and electronic systems. Here, the overall progress made to date in building such translational efforts at the level of an individual bacterial cell to a bacterial community is discussed.}, } @article {pmid32587287, year = {2020}, author = {do Nascimento Dias, J and de Souza Silva, C and de Araújo, AR and Souza, JMT and de Holanda Veloso Júnior, PH and Cabral, WF and da Glória da Silva, M and Eaton, P and de Souza de Almeida Leite, JR and Nicola, AM and Albuquerque, P and Silva-Pereira, I}, title = {Mechanisms of action of antimicrobial peptides ToAP2 and NDBP-5.7 against Candida albicans planktonic and biofilm cells.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {10327}, pmid = {32587287}, issn = {2045-2322}, mesh = {Amphotericin B/pharmacology/therapeutic use ; Animals ; Antifungal Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candidiasis/*drug therapy/microbiology ; Cell Membrane Permeability/drug effects ; Cell Wall/drug effects ; Disease Models, Animal ; Drug Resistance, Fungal ; Drug Synergism ; Drug Therapy, Combination/methods ; Fluconazole/pharmacology/therapeutic use ; Humans ; Microbial Sensitivity Tests ; Moths ; Pore Forming Cytotoxic Proteins/*pharmacology/therapeutic use ; }, abstract = {Candida albicans is a major cause of human infections, ranging from relatively simple to treat skin and mucosal diseases to systemic life-threatening invasive candidiasis. Fungal infections treatment faces three major challenges: the limited number of therapeutic options, the toxicity of the available drugs, and the rise of antifungal resistance. In this study, we demonstrate the antifungal activity and mechanism of action of peptides ToAP2 and NDBP-5.7 against planktonic cells and biofilms of C. albicans. Both peptides were active against C. albicans cells; however, ToAP2 was more active and produced more pronounced effects on fungal cells. Both peptides affected C. albicans membrane permeability and produced changes in fungal cell morphology, such as deformations in the cell wall and disruption of ultracellular organization. Both peptides showed synergism with amphotericin B, while ToAP2 also presents a synergic effect with fluconazole. Besides, ToAP2 (6.25 µM.) was able to inhibit filamentation after 24 h of treatment and was active against both the early phase and mature biofilms of C. albicans. Finally, ToAP2 was protective in a Galleria mellonella model of infection. Altogether these results point to the therapeutic potential of ToAP2 and other antimicrobial peptides in the development of new therapies for C. albicans infections.}, } @article {pmid32586125, year = {2020}, author = {Kannappan, A and Durgadevi, R and Srinivasan, R and Lagoa, RJL and Packiavathy, IASV and Pandian, SK and Veera Ravi, A}, title = {2-Hydroxy-4-methoxybenzaldehyde from Hemidesmus indicus is antagonistic to Staphylococcus epidermidis biofilm formation.}, journal = {Biofouling}, volume = {36}, number = {5}, pages = {549-563}, doi = {10.1080/08927014.2020.1777989}, pmid = {32586125}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*toxicity ; Benzaldehydes/*toxicity ; Biofilms/*drug effects ; Hemidesmus ; Humans ; Staphylococcal Infections ; Staphylococcus epidermidis/*drug effects ; }, abstract = {Staphylococcus epidermidis (SE) is an opportunistic nosocomial pathogen that accounts for recalcitrant device-related infections worldwide. Owing to the growing interest in plants and their secondary metabolites targeting bacterial adhesion, this study was intended to uncover the anti-biofilm potential of Hemidesmus indicus and its major constituent 2-hydroxy-4-methoxybenzaldehyde (HMB) against SE. The minimum biofilm inhibitory concentration (MBIC) of H. indicus root extract and HMB were found to be 500 and 250 µg ml[-1], respectively. The results of time-dependent biofilm inhibition and mature biofilm disruption assays confirmed that HMB targets initial cell adhesion. Furthermore, interference by HMB in the expression of adhesin genes (icaA, aap and bhp) and biofilm components was associated with an increased susceptibility of SE to oxidative stress and antibiotics. To conclude, this study reports for the first time HMB as a potential drug against SE biofilms.}, } @article {pmid32585940, year = {2020}, author = {Szymczyk-Ziółkowska, P and Hoppe, V and Rusińska, M and Gąsiorek, J and Ziółkowski, G and Dydak, K and Czajkowska, J and Junka, A}, title = {The Impact of EBM-Manufactured Ti6Al4V ELI Alloy Surface Modifications on Cytotoxicity toward Eukaryotic Cells and Microbial Biofilm Formation.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {12}, pages = {}, pmid = {32585940}, issn = {1996-1944}, support = {049M/0001/19//Politechnika Wrocławska/ ; SUB.D230.20.002//Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu/ ; }, abstract = {Electron beam melting (EBM) is an additive manufacturing technique, which allows forming customized implants that perfectly fit the loss of the anatomical structure of bone. Implantation efficiency depends not only on the implant's functional or mechanical properties but also on its surface properties, which are of great importance with regard to such biological processes as bone regeneration or microbial contamination. This work presents the impact of surface modifications (mechanical polishing, sandblasting, and acid-polishing) of EBM-produced Ti6Al4V ELI implants on essential biological parameters. These include wettability, cytotoxicity toward fibroblast and osteoblast cell line, and ability to form biofilm by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Obtained results indicated that all prepared surfaces exhibited hydrophilic character and the highest changes of wettability were obtained by chemical modification. All implants displayed no cytotoxicity against osteoblast and fibroblast cell lines regardless of the modification type. In turn, the quantitative microbiological tests and visualization of microbial biofilm by means of electron microscopy showed that type of implant's modification correlated with the species-specific ability of microbes to form biofilm on it. Thus, the results of the presented study confirm the relationship between such technological aspects as surface modification and biological properties. The provided data are useful with regard to applications of the EBM technology and present a significant step towards personalized, customized implantology practice.}, } @article {pmid32585445, year = {2020}, author = {Dornelas Figueira, LM and Ricomini Filho, AP and da Silva, WJ and Del BeL Cury, AA and Ruiz, KGS}, title = {Glucose effect on Candida albicans biofilm during tissue invasion.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104728}, doi = {10.1016/j.archoralbio.2020.104728}, pmid = {32585445}, issn = {1879-1506}, mesh = {*Biofilms ; *Candida albicans ; *Candidiasis ; Cells, Cultured ; Cytokines/metabolism ; Epithelial Cells/*microbiology ; Glucose/*pharmacology ; Humans ; }, abstract = {OBJECTIVE: To evaluate, in vitro, the effect of two glucose concentrations (0.1 mM and 1.0 mM, simulating glucose concentration in saliva of healthy and diabetic individuals) on Candida albicans biofilm grown on epithelial monolayer.

MATERIAL AND METHODS: C. albicans was inoculated on epithelial monolayers supplemented with 0.1 mM, 1.0 mM or no glucose. Control groups without C. albicans were also evaluated. Tissue response was assessed through the production of Interleukin-1α, Interleukin-8, Interleukin-6, Interleukin-10 and tumor necrosis factor-α. The complex of monolayer and biofilms were evaluated by quantitative reverse transcription polymerase chain reaction for expression of E-cadherin (CDH1), Caspase-3 (CASP3), β-defensin-1 (DEFB-1) and β-defensin-3 (DEFB-3). The biofilm architecture was visualized by confocal laser scanning microscopy.

RESULTS: The production of Interleukin-1α and Interleukin-8 were increased in the presence of C. albicans (p < 0.05). Glucose did not interfere in the release of any cytokine evaluated. C. albicans downregulated transcripts for CDH1 (p < 0.05). Glucose did not induce a significant change in CDH1, CASP3, DEFB-1 and DEFB-3 messenger RNA expression. The biofilms were more structured in the presence of glucose, but no difference in the diffusion of hyphae through the epithelial cells were observed.

CONCLUSIONS: The data suggest that glucose concentration does not affect the behavior of C. albicans during tissue invasion and other mechanisms must be related to the greater susceptibility of diabetic individuals to candidiasis.}, } @article {pmid32585104, year = {2020}, author = {Li, Y and Liu, X and Li, B and Zheng, Y and Han, Y and Chen, DF and Yeung, KWK and Cui, Z and Liang, Y and Li, Z and Zhu, S and Wang, X and Wu, S}, title = {Near-Infrared Light Triggered Phototherapy and Immunotherapy for Elimination of Methicillin-Resistant Staphylococcus aureus Biofilm Infection on Bone Implant.}, journal = {ACS nano}, volume = {14}, number = {7}, pages = {8157-8170}, doi = {10.1021/acsnano.0c01486}, pmid = {32585104}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Immunotherapy ; *Methicillin-Resistant Staphylococcus aureus ; Osteogenesis ; Phototherapy ; }, abstract = {Clinically, methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection inevitably induces the failure of bone implants. Herein, a hydrophilic and viscous hydrogel of poly(vinyl alcohol) modified with chitosan, polydopamine, and NO release donor was formed on a red phosphorus nanofilm deposited on a titanium implant (Ti-RP/PCP/RSNO). Under the irradiation of near-infrared light (NIR), peroxynitrite ([•]ONOO[-]) was formed by the reaction between the released NO and superoxide ([•]O2[-]) produced by the RP nanofilm. Specifically, we revealed the antibacterial mechanism of the ONOO[-] against the MRSA biofilm. In addition, osteogenic differentiation was promoted and inflammatory polarization was regulated by the released NO without NIR irradiation through upregulating the expression of Opn and Ocn genes and TNF-α. The MRSA biofilm was synergistically eradicated by [•]ONOO[-], hyperthermia, and [•]O[2-] under NIR irradiation as well as the immunoreaction of the M1 polarization. The in vivo results also confirmed the excellent osteogenesis and biofilm eradication by released NO from the RP/PCP/RSNO system under NIR irradiation, indicating the noninvasive tissue reconstruction of MRSA-infected tissues through phototherapy and immunotherapy.}, } @article {pmid32584995, year = {2020}, author = {Costa, ACBP and Back-Brito, GN and Mayer, FL and Hube, B and Wilson, D}, title = {Candida albicans Mrv8, is involved in epithelial damage and biofilm formation.}, journal = {FEMS yeast research}, volume = {20}, number = {5}, pages = {}, pmid = {32584995}, issn = {1567-1364}, support = {214317/Z/18/Z/WT_/Wellcome Trust/United Kingdom ; 09 7377/Z/11/Z/WT_/Wellcome Trust/United Kingdom ; MR/N006364/1/MRC_/Medical Research Council/United Kingdom ; MR/N006364/2/MRC_/Medical Research Council/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Antifungal Agents/pharmacology ; *Biofilms/drug effects ; Candida albicans/drug effects/*pathogenicity ; Cell Line, Tumor ; Fungal Proteins/genetics/*metabolism ; Host-Pathogen Interactions ; Humans ; Mouth Mucosa/*microbiology ; }, abstract = {Candida albicans is the most common human fungal pathogen that can cause superficial and deep-seated infections in susceptible individuals. Despite its medical importance, the vast majority of C. albicans genes remain of unknown function. Here, we report a role for the lineage-specific gene, MRV8, in host pathogen interactions, mycelial microcolony maturation and biofilm formation. In silico analysis indicated that MRV8 encodes a four-pass transmembrane protein unique to the closely related pathogens C. albicans and Candida dubliniensis. Deletion of MRV8 did not affect C. albicans adherence to, or initial invasion into human oral epithelia, but inhibited mycelial development and strongly reduced epithelial damage. mrv8Δ/Δ cells exhibited a media-dependent defect in biofilm formation and mutant biofilm metabolic activity was enhanced by cyclosporin A. mrv8Δ/Δ biofilms were more tolerant to treatment with caspofungin, but not to fluconazole or amphotericin B. Co-stimulation with calcium chloride and calcofluor white rescued biofilm growth in the presence of caspofungin, and this rescue-effect was Mrv8-dependent. Together, our data demonstrate an important role for a lineage-specific gene (MRV8) in C. albicans biofilm formation, drug tolerance and host-pathogen interactions.}, } @article {pmid32583509, year = {2020}, author = {Desch, A and Freifrau von Maltzahn, N and Stumpp, N and Dalton, M and Yang, I and Stiesch, M}, title = {Biofilm formation on zirconia and titanium over time-An in vivo model study.}, journal = {Clinical oral implants research}, volume = {31}, number = {9}, pages = {865-880}, doi = {10.1111/clr.13632}, pmid = {32583509}, issn = {1600-0501}, mesh = {Biofilms ; Humans ; Surface Properties ; Time ; *Titanium ; *Zirconium ; }, abstract = {OBJECTIVES: The aim of this study was to evaluate volume, vitality and diversity of biofilms on the abutment materials zirconia and titanium as a function of time using an in vivo model for the biofilm formation.

MATERIALS AND METHODS: The development of biofilms on zirconia and titanium grade 4 test specimens in the human oral cavity over time was analysed. After pretreatment, a total of 96 titanium and 96 zirconia discs were fixed on 12 composite splints, which were worn by 12 volunteers. After 6 hr, 24 hr, 3 days and 5 days, biofilms on 48 specimens of each material were analysed with confocal laser scanning microscopy (CLSM). The microbiota composition on the other 48 test specimens was examined using full-length 16S sequence analysis. Statistical analysis was performed by SPSS and R, and level of significance was set at 0.05.

RESULTS: Confocal laser scanning microscopy analysis of the biofilms revealed significant changes in volume over time on zirconia and titanium. The material did not significantly influence the volume or live/dead ratio at the individual time points. The composition of the microbiome was influenced by the age of the biofilm, but not by the material of the test specimen. The most frequently found bacteria were Streptococcus spp., followed by Neisseria spp., Rothia spp., Haemophilus spp., Gemella spp. and Abiotrophia spp.

CONCLUSIONS: On both materials, the quantity and diversity of the microbiome increased over time. Apart from a slight difference in Veillonella abundance at one time point, there were no significant differences between zirconia and titanium.}, } @article {pmid32583190, year = {2020}, author = {Kallscheuer, N and Wiegand, S and Boedeker, C and Peeters, SH and Jogler, M and Heuer, A and Jetten, MSM and Rohde, M and Jogler, C}, title = {Caulifigura coniformis gen. nov., sp. nov., a novel member of the family Planctomycetaceae isolated from a red biofilm sampled in a hydrothermal area.}, journal = {Antonie van Leeuwenhoek}, volume = {113}, number = {12}, pages = {1927-1937}, pmid = {32583190}, issn = {1572-9699}, support = {KA 4967/1-1//DFG/ ; JO 893/4-1//DFG/ ; ALWOP.308//Nederlandse Organisatie voor Wetenschappelijk Onderzoek/ ; 024002002//Soehngen Institute for Anaerobic Microbiology/ ; }, mesh = {Bacterial Typing Techniques ; Base Composition ; Biofilms ; DNA, Bacterial ; Fatty Acids/analysis ; Phylogeny ; *Planctomycetales/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {Pan44[T], a novel strain belonging to the phylum Planctomycetes, was isolated from a red biofilm in a hydrothermal area close to the island Panarea in the Tyrrhenian Sea north of Sicily, Italy. The strain forms white colonies on solid medium and displays the following characteristics: cell division by budding, formation of rosettes, presence of matrix or fimbriae and long stalks. The cell surface has an interesting and characteristic texture made up of triangles and rectangles, which leads to a pine cone-like morphology of the strain. Strain Pan44[T] is mesophilic (temperature optimum 26 °C), slightly alkaliphilic (pH optimum 8.0), aerobic and heterotrophic. The strain has a genome size of 6.76 Mb with a G + C content of 63.2%. Phylogenetically, the strain is a member of the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. Our analysis supports delineation of strain Pan44[T] from all known genera in this family, hence, we propose to assign it to a novel species within a novel genus, for which we propose the name Caulifigura coniformis gen. nov., sp. nov., represented by Pan44[T] (DSM 29405[T] = LMG 29788[T]) as the type strain.}, } @article {pmid32582564, year = {2020}, author = {Kim, JH and Ruegger, PR and Lebig, EG and VanSchalkwyk, S and Jeske, DR and Hsiao, A and Borneman, J and Martins-Green, M}, title = {High Levels of Oxidative Stress Create a Microenvironment That Significantly Decreases the Diversity of the Microbiota in Diabetic Chronic Wounds and Promotes Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {259}, pmid = {32582564}, issn = {2235-2988}, support = {R21 AI138188/AI/NIAID NIH HHS/United States ; R35 GM124724/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms ; Corynebacterium ; *Diabetes Mellitus ; Humans ; *Microbiota ; Oxidative Stress ; Pseudomonas aeruginosa ; Staphylococcus ; }, abstract = {Diabetics chronic wounds are characterized by high levels of oxidative stress (OS) and are often colonized by biofilm-forming bacteria that severely compromise healing and can result in amputation. However, little is known about the role of skin microbiota in wound healing and chronic wound development. We hypothesized that high OS levels lead to chronic wound development by promoting the colonization of biofilm-forming bacteria over commensal/beneficial bacteria. To test this hypothesis, we used our db/db[-/-] mouse model for chronic wounds where pathogenic biofilms develop naturally after induction of high OS immediately after wounding. We sequenced the bacterial rRNA internal transcribed spacer (ITS) gene of the wound microbiota from wound initiation to fully developed chronic wounds. Indicator species analysis, which considers a species' fidelity and specificity, was used to determine which bacterial species were strongly associated with healing wounds or chronic wounds. We found that healing wounds were colonized by a diverse and dynamic bacterial microbiome that never developed biofilms even though biofilm-forming bacteria were present. Several clinically relevant species that are present in human chronic wounds, such as Cutibacterium acnes, Achromobacter sp., Delftia sp., and Escherichia coli, were highly associated with healing wounds. These bacteria may serve as bioindicators of healing and may actively participate in the processes of wound healing and preventing pathogenic bacteria from colonizing the wound. In contrast, chronic wounds, which had high levels of OS, had low bacterial diversity and were colonized by several clinically relevant, biofilm-forming bacteria such as Pseudomonas aeruginosa, Enterobacter cloacae, Corynebacterium frankenforstense, and Acinetobacter sp. We observed unique population trends: for example, P. aeruginosa associated with aggressive biofilm development, whereas Staphylococcus xylosus was only present early after injury. These findings show that high levels of OS in the wound significantly altered the bacterial wound microbiome, decreasing diversity and promoting the colonization of bacteria from the skin microbiota to form biofilm. In conclusion, bacteria associated with non-chronic or chronic wounds could function as bioindicators of healing or non-healing (chronicity), respectively. Moreover, a better understanding of bacterial interactions between pathogenic and beneficial bacteria within an evolving chronic wound microbiota may lead to better solutions for chronic wound management.}, } @article {pmid32582122, year = {2020}, author = {Yan, J and Xie, J}, title = {Comparative Proteome Analysis of Shewanella putrefaciens WS13 Mature Biofilm Under Cold Stress.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1225}, pmid = {32582122}, issn = {1664-302X}, abstract = {Worldwide, Shewanella putrefaciens is the predominant seafood spoilage microorganism during cold storage. This bacterium can attach to biotic/abiotic surfaces to form biofilms which contribute to seafood quality degradation and shelf-life reduction. The mechanism of S. putrefaciens biofilm formation is not yet described. Crystal violet staining in combination with confocal laser scanning microscopy (CLSM) was used to study the sequence of events leading to the establishment of a mature biofilm at 4, 15, and 30°C. In addition, the main chemical constituents of the mature biofilm were determined by Raman spectroscopy (RM), whereas, comparative proteomic analysis was used to quantify changes in metabolic pathways and to find out underlying protein determinants. The physical dimensions of the mature biofilm, i.e., biomass, biovolume, and mean thickness, were higher at 4°C when compared to 15 and 30°C. The variations of proteins measured by RM confirmed the importance of proteins during the formation of a mature biofilm. Comparative proteomic analysis showed that siderophore and iron chelate transport proteins were down-regulated during mature biofilm formation. The down-regulated aforementioned proteins are involved in promoting iron storage in response to a higher demand for metabolic energy, whereas, the upregulated proteins of the sulfur relay system, pyrimidine metabolism, and purine metabolism are related to bacterial adaptability. Synthesis of proteins related to cold stress was increased and proteins involved in aminoacyl-tRNA biosynthesis were up-regulated, whereas, proteins involved in aminopeptidase activity were down-regulated. Proteolysis to scavenge energy was reduced as proteins involved in pyrophosphatase activity were up-regulated. Also extracellular eDNA was found which may play an important role in maintaining the stability of mature S. putrefaciens biofilm structures under cold stress. This work provides a better understanding of the role of proteins in mature biofilms. In addition, the biofilm formation mechanism of a psychrotrophic spoilage bacterial species at low temperature is explored, which may contribute to generating biofilm controlling strategies during seafood preservation and processing.}, } @article {pmid32582085, year = {2020}, author = {Trego, AC and Galvin, E and Sweeney, C and Dunning, S and Murphy, C and Mills, S and Nzeteu, C and Quince, C and Connelly, S and Ijaz, UZ and Collins, G}, title = {Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1126}, pmid = {32582085}, issn = {1664-302X}, support = {MR/L015080/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Methanogenic sludge granules are densely packed, small, spherical biofilms found in anaerobic digesters used to treat industrial wastewaters, where they underpin efficient organic waste conversion and biogas production. Each granule theoretically houses representative microorganisms from all of the trophic groups implicated in the successive and interdependent reactions of the anaerobic digestion (AD) process. Information on exactly how methanogenic granules develop, and their eventual fate will be important for precision management of environmental biotechnologies. Granules from a full-scale bioreactor were size-separated into small (0.6-1 mm), medium (1-1.4 mm), and large (1.4-1.8 mm) size fractions. Twelve laboratory-scale bioreactors were operated using either small, medium, or large granules, or unfractionated sludge. After >50 days of operation, the granule size distribution in each of the small, medium, and large bioreactor sets had diversified beyond-to both bigger and smaller than-the size fraction used for inoculation. Interestingly, extra-small (XS; <0.6 mm) granules were observed, and retained in all of the bioreactors, suggesting the continuous nature of granulation, and/or the breakage of larger granules into XS bits. Moreover, evidence suggested that even granules with small diameters could break. "New" granules from each emerging size were analyzed by studying community structure based on high-throughput 16S rRNA gene sequencing. Methanobacterium, Aminobacterium, Propionibacteriaceae, and Desulfovibrio represented the majority of the community in new granules. H2-using, and not acetoclastic, methanogens appeared more important, and were associated with abundant syntrophic bacteria. Multivariate integration (MINT) analyses identified distinct discriminant taxa responsible for shaping the microbial communities in different-sized granules.}, } @article {pmid32582081, year = {2020}, author = {Wu, X and Zhang, S and Li, H and Shen, L and Dong, C and Sun, Y and Chen, H and Xu, B and Zhuang, W and Deighton, M and Qu, Y}, title = {Biofilm Formation of Candida albicans Facilitates Fungal Infiltration and Persister Cell Formation in Vaginal Candidiasis.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1117}, pmid = {32582081}, issn = {1664-302X}, abstract = {BACKGROUND: Vaginal candidiasis is an important medical condition awaiting more effective treatment. How Candida albicans causes this disease and survives antifungal treatment is not yet fully understood. This study aimed to establish a comprehensive understanding of biofilm-related defensive strategies that C. albicans uses to establish vaginal candidiasis and to survive antifungal treatment.

METHODS: A mouse model of vaginal candidiasis was adopted to examine the formation of biotic biofilms on the vaginal epithelium and fungal infiltration by laboratory and clinical strains of C. albicans. Histopathological changes and local inflammation in the vaginal epithelium caused by C. albicans of different biofilm phenotypes were compared. Antifungal susceptibility testing was carried out for C. albicans grown as planktonic cells, microplate-based abiotic biofilms, and epithelium-based biotic biofilms. Formation of persister cells by C. albicans in different growth modes was also quantified and compared.

RESULTS: C. albicans wild-type reference strains and clinical isolates, but not the biofilm-defective mutants, formed a significant number of biotic biofilms on the vaginal epithelium of mice and infiltrated the epithelium. Biofilm formation and epithelial invasion induced local inflammatory responses and histopathological changes in the vaginal epithelium including neutrophil infiltration and subcorneal microabscesses. Biofilm growth on the vaginal epithelium also led to high resistance to antifungal treatments and promoted the formation of antifungal-tolerant persister cells.

CONCLUSION: This study comprehensively assessed biofilm-related microbial strategies that C. albicans uses in vaginal candidiasis and provided experimental evidence to support the important role of biofilm formation in the histopathogenesis of vaginal candidiasis and the recalcitrance of the infection to antifungal treatment.}, } @article {pmid32579104, year = {2020}, author = {Choo, S and Borchert, E and Wiese, J and Saha, M and Künzel, S and Weinberger, F and Hentschel, U}, title = {Polaribacter septentrionalilitoris sp. nov., isolated from the biofilm of a stone from the North Sea.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {70}, number = {7}, pages = {4305-4314}, doi = {10.1099/ijsem.0.004290}, pmid = {32579104}, issn = {1466-5034}, mesh = {Bacterial Typing Techniques ; Base Composition ; *Biofilms ; Carotenoids/chemistry ; DNA, Bacterial/genetics ; Fatty Acids/chemistry ; Flavobacteriaceae/*classification/isolation & purification ; North Sea ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Vitamin K 2/analogs & derivatives/chemistry ; }, abstract = {A new member of the family Flavobacteriaceae was isolated from the biofilm of a stone at Nordstrand, a peninsula at the German North Sea shore. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain ANORD1[T] was most closely related to the validly described type strains Polaribacter porphyrae LNM-20[T] (97.0 %) and Polaribacter reichenbachii KMM 6386[T] (96.9 % 16S rRNA gene sequence similarity) and clustered with Polaribacter gangjinensis K17-16[T] (96.0 %). Strain ANORD1[T] was determined to be mesophilic, Gram-negative, non-motile and strictly aerobic. Optimal growth was observed at 20-30 °C, within a salinity range of 2-7 % sea salt and from pH 7-10. Like other type strains of the genus Polaribacter, ANORD1[T] was tested negative for flexirubin-type pigments, while carotenoid-type pigments were detected. The DNA G+C content of strain ANORD1[T] was 30.6 mol%. The sole respiratory quinone detected was menaquinone 6 (MK-6). The major fatty acids identified were C15 : 0, iso-C15 : 0, C15 : 1 ω6c and iso-C15 : 0 3-OH. Based on the polyphasic approach, strain ANORD1[T] represents a novel species in the genus Polaribacter, with the name Polaribacter septentrionalilitoris sp. nov. being proposed. The type strain is ANORD1[T] (=DSM 110039[T]=NCIMB 15081[T]=MTCC 12685[T]).}, } @article {pmid32578800, year = {2020}, author = {Silva, AM and Miranda, LFB and AraÚjo, ASM and Prado JÚnior, RR and Mendes, RF}, title = {Electric toothbrush for biofilm control in individuals with Down syndrome: a crossover randomized clinical trial.}, journal = {Brazilian oral research}, volume = {34}, number = {}, pages = {e057}, doi = {10.1590/1807-3107bor-2020.vol34.0057}, pmid = {32578800}, issn = {1807-3107}, mesh = {Adolescent ; Adolescent Behavior ; *Biofilms ; Caregivers ; Child ; Child Behavior ; Cross-Over Studies ; Dental Caries/prevention & control ; *Dental Devices, Home Care ; Dental Plaque/*prevention & control ; Down Syndrome/*physiopathology ; Equipment Design ; Female ; Humans ; Male ; Statistics, Nonparametric ; Time Factors ; Toothbrushing/*instrumentation ; Treatment Outcome ; }, abstract = {Poor oral hygiene seems to be the norm in children and teenagers with Down Syndrome (DS). Advances in design and types of toothbrushes may improve biofilm control. This randomized, single-blind, crossover clinical trial evaluated the effectiveness of electric toothbrushes regarding mechanical control of biofilm in children and teenagers with DS and their cooperation. Twenty-nine participants with DS, aged 6 to 14 years, used both types of toothbrushes: electric (ET) and manual (MT). The order of use of the different types of toothbrushes was randomly defined, including a 7-day period with each type with 7-day washout period in between. The Turesky-Quigley-Hein biofilm index was used before and after brushing to assess the effectiveness of the technique. Frankl's behavioral scale was used during toothbrushing to assess the participants' cooperation. Paired T-test, Mann Whitney, Chi-square, and Fisher's Exact tests were applied, with a significance level of 5%. The quantity of dental biofilm was significantly reduced after both brushing techniques (p < 0.001). However, no significant difference was found in total biofilm (ET: 0.73 ± 0.36; MT: 0.73 ± 0.34; p = 0.985) or % biofilm reduction (ET: 72.22%; MT: 70.96%; p = 0.762) after brushing between techniques or in % biofilm reduction between toothbrushes of age groups (6 -9 years, p = 0.919; 10-14 years, p = 0.671). Participants showed similar cooperation level with the two types of toothbrush (p = 1.000). The use of electric or manual toothbrush had no effect on the quantity of dental biofilm removed in children and teenagers with DS, nor did it influence their cooperation during the procedure.}, } @article {pmid32577899, year = {2020}, author = {Bulut, F and Cumbul, A and Safak, AS}, title = {An analysis of the histomorphometric and clinical significance of mucosal biofilm in tonsil tissue of the children with a history of recurrent/chronic tonsillitis in both the mother and father.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {277}, number = {12}, pages = {3381-3389}, pmid = {32577899}, issn = {1434-4726}, mesh = {Biofilms ; Child ; Child, Preschool ; Fathers ; Female ; Humans ; Male ; Mothers ; Palatine Tonsil ; Recurrence ; *Tonsillectomy ; *Tonsillitis/surgery ; }, abstract = {PURPOSE: The aim of this study is to analyse the histomorphometric and clinical features of the mucosal biofilm in tonsil tissue of children with a history of recurrent/chronic tonsillitis in both the mother and father.

METHODS: This study enrolled 82 children (between 3 and 14 years of age). These children were divided into two main groups according to the present of recurrent/chronic tonsillitis. Patients in group 1 were divided into four subgroups (A, B, C, D) according to the history of recurrent/chronic tonsillitis in mother and/or father. 30 patients in group 1 were underwent tonsillectomy and the 52 patients in control group (2) have not had history of recurrent/chronic tonsillitis. To that end, among children with a history of recurrent/chronic tonsillitis certain changes in the volume and thickness of mucosal biofilm in tonsil tissue have been exhibited with respect to it is histomorphometric and clinical significance.

RESULTS: The children with a parental history of recurrent/chronic tonsillitis in group A, an increase in the thickness and volume of mucosal biofilm samples was detected according to the other subgroups (B, C, D). Parents history of group A patients statistically significant differences were detected with respect to halitosis symptoms, attack age of the first tonsillitis and resistant fever despite antibiotic treatment for children under the age of 3 years.

CONCLUSIONS: This study showed that children under the age of 3 years of age with a history of recurrent/chronic tonsillitis in both the mother and father, halitosis symptoms, attack age of the first tonsillitis and resistant fever despite antibiotic treatment are collectively linked.}, } @article {pmid32576676, year = {2020}, author = {Walsh, BJC and Wang, J and Edmonds, KA and Palmer, LD and Zhang, Y and Trinidad, JC and Skaar, EP and Giedroc, DP}, title = {The Response of Acinetobacter baumannii to Hydrogen Sulfide Reveals Two Independent Persulfide-Sensing Systems and a Connection to Biofilm Regulation.}, journal = {mBio}, volume = {11}, number = {3}, pages = {}, pmid = {32576676}, issn = {2150-7511}, support = {F32 AI122516/AI/NIAID NIH HHS/United States ; T32 GM109825/GM/NIGMS NIH HHS/United States ; R01 AI101171/AI/NIAID NIH HHS/United States ; R35 GM118157/GM/NIGMS NIH HHS/United States ; T32 GM131994/GM/NIGMS NIH HHS/United States ; K99 HL143441/HL/NHLBI NIH HHS/United States ; }, mesh = {Acinetobacter baumannii/*drug effects/*genetics ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Regulator ; Hydrogen Sulfide/*metabolism/*pharmacology ; Proteomics ; Sulfides/metabolism/pharmacology ; Transcription Factors/genetics/metabolism ; }, abstract = {Acinetobacter baumannii is an opportunistic nosocomial pathogen that is the causative agent of several serious infections in humans, including pneumonia, sepsis, and wound and burn infections. A. baumannii is also capable of forming proteinaceous biofilms on both abiotic and epithelial cell surfaces. Here, we investigate the response of A. baumannii toward sodium sulfide (Na2S), known to be associated with some biofilms at oxic/anoxic interfaces. The addition of exogenous inorganic sulfide reveals that A. baumannii encodes two persulfide-sensing transcriptional regulators, a primary σ[54]-dependent transcriptional activator (FisR), and a secondary system controlled by the persulfide-sensing biofilm growth-associated repressor (BigR), which is only induced by sulfide in a fisR deletion strain. FisR activates an operon encoding a sulfide oxidation/detoxification system similar to that characterized previously in Staphylococcus aureus, while BigR regulates a secondary persulfide dioxygenase (PDO2) as part of yeeE-yedE-pdo2 sulfur detoxification operon, found previously in Serratia spp. Global S-sulfuration (persulfidation) mapping of the soluble proteome reveals 513 persulfidation targets well beyond FisR-regulated genes and includes five transcriptional regulators, most notably the master biofilm regulator BfmR and a poorly characterized catabolite regulatory protein (Crp). Both BfmR and Crp are well known to impact biofilm formation in A. baumannii and other organisms, respectively, suggesting that persulfidation of these regulators may control their activities. The implications of these findings on bacterial sulfide homeostasis, persulfide signaling, and biofilm formation are discussed.IMPORTANCE Although hydrogen sulfide (H2S) has long been known as a respiratory poison, recent reports in numerous bacterial pathogens reveal that H2S and more downstream oxidized forms of sulfur collectedly termed reactive sulfur species (RSS) function as antioxidants to combat host efforts to clear the infection. Here, we present a comprehensive analysis of the transcriptional and proteomic response of A. baumannii to exogenous sulfide as a model for how this important human pathogen manages sulfide/RSS homeostasis. We show that A. baumannii is unique in that it encodes two independent persulfide sensing and detoxification pathways that govern the speciation of bioactive sulfur in cells. The secondary persulfide sensor, BigR, impacts the expression of biofilm-associated genes; in addition, we identify two other transcriptional regulators known or projected to regulate biofilm formation, BfmR and Crp, as highly persulfidated in sulfide-exposed cells. These findings significantly strengthen the connection between sulfide homeostasis and biofilm formation in an important human pathogen.}, } @article {pmid32576670, year = {2020}, author = {Béchon, N and Mihajlovic, J and Vendrell-Fernández, S and Chain, F and Langella, P and Beloin, C and Ghigo, JM}, title = {Capsular Polysaccharide Cross-Regulation Modulates Bacteroides thetaiotaomicron Biofilm Formation.}, journal = {mBio}, volume = {11}, number = {3}, pages = {}, pmid = {32576670}, issn = {2150-7511}, mesh = {Animals ; Bacterial Adhesion/genetics ; Bacterial Capsules/chemistry/*genetics ; Bacteroides thetaiotaomicron/*genetics/*physiology ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Male ; Mice ; Mice, Inbred C3H ; Mutagenesis ; Polysaccharides, Bacterial/*chemistry ; Specific Pathogen-Free Organisms ; }, abstract = {Bacteroides thetaiotaomicron is one of the most abundant gut symbiont species, whose contribution to host health through its ability to degrade dietary polysaccharides and mature the immune system is under intense scrutiny. In contrast, adhesion and biofilm formation, which are potentially involved in gut colonization and microbiota structure and stability, have hardly been investigated in this intestinal bacterium. To uncover B. thetaiotaomicron biofilm-related functions, we performed a transposon mutagenesis in the poorly biofilm-forming reference strain VPI-5482 and showed that capsule 4, one of the eight B. thetaiotaomicron capsules, hinders biofilm formation. We then showed that the production of capsules 1, 2, 3, 5, and 6 also inhibits biofilm formation and that decreased capsulation of the population correlated with increased biofilm formation, suggesting that capsules could be masking adhesive surface structures. In contrast, we showed that capsule 8 displayed intrinsic adhesive properties. Finally, we demonstrated that BT2934, the wzx homolog of the B. thetaiotaomicron glycosylation locus, competes with capsule production and impacts its adhesion capacity. This study therefore establishes B. thetaiotaomicron capsule regulation as a major determinant of B. thetaiotaomicron biofilm formation, providing new insights into how modulation of different B. thetaiotaomicron surface structures affects in vitro biofilm formation.IMPORTANCE The human gut harbors a complex bacterial community that plays important roles in host health and disease, including nutrient acquisition, maturation of the immune system, and resistance to infections. The capacity to adhere to surfaces and form communities called biofilms is believed to be important for niche colonization and maintenance of gut bacteria. However, little is known about the adhesion capacity of most gut bacteria. In this study, we investigated biofilm formation in Bacteroides thetaiotaomicron, one of the most abundant bacteria of the normal mammalian intestine. We identified that B. thetaiotaomicron capsules, a group of eight surface-exposed polysaccharidic layers mediating important interactions with the gut environment, are also major determinants of biofilm formation that mask or unmask adhesion factors. Studying how B. thetaiotaomicron regulates its adhesion properties will allow us to better understand the physiology and specific properties of this important gut symbiont within anaerobic biofilms.}, } @article {pmid32576653, year = {2020}, author = {Simmons, EL and Bond, MC and Koskella, B and Drescher, K and Bucci, V and Nadell, CD}, title = {Biofilm Structure Promotes Coexistence of Phage-Resistant and Phage-Susceptible Bacteria.}, journal = {mSystems}, volume = {5}, number = {3}, pages = {}, pmid = {32576653}, issn = {2379-5077}, support = {P20 GM113132/GM/NIGMS NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; R01 AI081838/AI/NIAID NIH HHS/United States ; T32 HL134598/HL/NHLBI NIH HHS/United States ; }, abstract = {Encounters among bacteria and their viral predators (bacteriophages) are among the most common ecological interactions on Earth. These encounters are likely to occur with regularity inside surface-bound communities that microbes most often occupy in natural environments. Such communities, termed biofilms, are spatially constrained: interactions become limited to near neighbors, diffusion of solutes and particulates can be reduced, and there is pronounced heterogeneity in nutrient access and physiological state. It is appreciated from prior theoretical work that phage-bacteria interactions are fundamentally different in spatially structured contexts, as opposed to well-mixed liquid culture. Spatially structured communities are predicted to promote the protection of susceptible host cells from phage exposure, and thus weaken selection for phage resistance. The details and generality of this prediction in realistic biofilm environments, however, are not known. Here, we explore phage-host interactions using experiments and simulations that are tuned to represent the essential elements of biofilm communities. Our simulations show that in biofilms, phage-resistant cells-as their relative abundance increases-can protect clusters of susceptible cells from phage exposure, promoting the coexistence of susceptible and phage-resistant bacteria under a large array of conditions. We characterize the population dynamics underlying this coexistence, and we show that coexistence is recapitulated in an experimental model of biofilm growth measured with confocal microscopy. Our results provide a clear view into the dynamics of phage resistance in biofilms with single-cell resolution of the underlying cell-virion interactions, linking the predictions of canonical theory to realistic models and in vitro experiments of biofilm growth.IMPORTANCE In the natural environment, bacteria most often live in communities bound to one another by secreted adhesives. These communities, or biofilms, play a central role in biogeochemical cycling, microbiome functioning, wastewater treatment, and disease. Wherever there are bacteria, there are also viruses that attack them, called phages. Interactions between bacteria and phages are likely to occur ubiquitously in biofilms. We show here, using simulations and experiments, that biofilms will in most conditions allow phage-susceptible bacteria to be protected from phage exposure, if they are growing alongside other cells that are phage resistant. This result has implications for the fundamental ecology of phage-bacteria interactions, as well as the development of phage-based antimicrobial therapeutics.}, } @article {pmid32576596, year = {2020}, author = {Rodríguez López, AL and Lee, MR and Wang, NB and Dunn, KK and Sanchez, H and Raman, N and Andes, DR and Lynn, DM and Palecek, SP}, title = {Correction for Rodríguez López et al., "Small-Molecule Morphogenesis Modulators Enhance the Ability of 14-Helical β-Peptides To Prevent Candida albicans Biofilm Formation".}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {7}, pages = {}, doi = {10.1128/AAC.00841-20}, pmid = {32576596}, issn = {1098-6596}, } @article {pmid32575628, year = {2020}, author = {Singh, R and Dubey, AK}, title = {Isolation and Characterization of a New Endophytic Actinobacterium Streptomyces californicus Strain ADR1 as a Promising Source of Anti-Bacterial, Anti-Biofilm and Antioxidant Metabolites.}, journal = {Microorganisms}, volume = {8}, number = {6}, pages = {}, pmid = {32575628}, issn = {2076-2607}, abstract = {In view of the fast depleting armamentarium of drugs against significant pathogens, like methicillin-resistant Staphylococcus aureus (MRSA) and others due to rapidly emerging drug-resistance, the discovery and development of new drugs need urgent action. In this endeavor, a new strain of endophytic actinobacterium was isolated from the plant Datura metesl, which produced secondary metabolites with potent anti-infective activities. The isolate was identified as Streptomyces californicus strain ADR1 based on 16S rRNA gene sequence analysis. Metabolites produced by the isolate had been investigated for their antibacterial attributes against important pathogens: S. aureus, MRSA, S. epidermis, Enterococcus faecium and E. faecalis. Minimum inhibitory concentration (MIC90) values against these pathogens varied from 0.23 ± 0.01 to 5.68 ± 0.20 μg/mL. The metabolites inhibited biofilm formation by the strains of S. aureus and MRSA (Biofilm inhibitory concentration [BIC90] values: 0.74 ± 0.08-4.92 ± 0.49 μg/mL). The BIC90 values increased in the case of pre-formed biofilms. Additionally, the metabolites possessed good antioxidant properties, with an inhibitory concentration (IC90) value of 217.24 ± 6.77 µg/mL for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. An insight into different classes of compounds produced by the strain ADR1 was obtained by chemical profiling and GC-MS analysis, wherein several therapeutic classes, for example, alkaloids, phenolics, terpenes, terpenoids and glycosides, were discovered.}, } @article {pmid32574911, year = {2020}, author = {Ma, Y and Zhang, Z and Nitin, N and Sun, G}, title = {Integration of photo-induced biocidal and hydrophilic antifouling functions on nanofibrous membranes with demonstrated reduction of biofilm formation.}, journal = {Journal of colloid and interface science}, volume = {578}, number = {}, pages = {779-787}, doi = {10.1016/j.jcis.2020.06.037}, pmid = {32574911}, issn = {1095-7103}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Biofouling/prevention & control ; Hydrophobic and Hydrophilic Interactions ; *Nanofibers ; }, abstract = {Survival and pathogenic microbial adhesions on surfaces of materials followed by the formation of biofilms with robust resistance to antibiotics constitute the forefront of disease transmissions. Conventional strategies responding to this challenge are rather limited due to the biofouling effect of microorganisms or the irreversible consumption of antimicrobial agents embedded into the materials. Herein, we report an approach of combining photo-induced rechargeable biocidal properties with microbial resisting and releasing zwitterionic hydrophilic functions on surfaces of materials to improve antifouling performances. Poly(vinyl alcohol-co-ethylene) (EVOH) nanofibrous membranes (NFMs) were chemically incorporated with both 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BPTCD), a photoactive chemical, and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), a zwitterionic monomer. Both functional agents work independently and construct concerted microbial resisting, killing, and releasing functions to reduce microbial contamination and biofilm formation. The resulted SBMA@EVOH NFMs exhibited integrated features of large ROS production capacity, ease of photoactive rechargeability and controllability, long-term stability, high biocidal efficacy (>99.9999% via contact killing), and promising antifouling performance, which enable the SBMA@EVOH NFMs to serve as a biocidal material for food safety and medical applications.}, } @article {pmid32574876, year = {2020}, author = {Yuan, K and Li, S and Zhong, F}, title = {Treatment of coking wastewater in biofilm-based bioaugmentation process: Biofilm formation and microbial community analysis.}, journal = {Journal of hazardous materials}, volume = {400}, number = {}, pages = {123117}, doi = {10.1016/j.jhazmat.2020.123117}, pmid = {32574876}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors ; *Coke ; Humans ; *Microbiota ; Nitrogen/analysis ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Coking wastewater (CWW) containing complicated organic compositions and strong toxicity cause potential hazards to natural water bodies as well as human health. The aim of this study was integrating newly isolated Comamonas sp. ZF-3, biofilm-based bioaugmentation and fluidized bed reactor into an anoxic filter-fluidized bed reactor (AF-FBR) system to treat actual CWW. The results showed that 93 % of chemical oxygen demand (COD) and 97 % of ammonia nitrogen (NH4[+]-N) removal efficiency were achieved with hydraulic retention time of 70 h. The main pollutants including phenolic compounds, heterocyclic compounds and polycyclic aromatic hydrocarbons could be removed via biofilm-based process in AF-FBR. The formation of carrier biofilm was consistent with the system performance as well as the biofilm community evolution, during which the microbial community was gradually dominated by some functional genus (e.g., Comamonas, Thiobacillus, Pseudomonas and Thauera), meanwhile, ammonium-oxidizing bacteria Nitrosomonas, nitrite-oxidizing bacteria Nitrospira and denitrifiers (e.g., Pseudomonas, Thiobacillus and Bacillus) coexisted in biofilm to form a microbial community for biological nitrogen removal. Such microbial community structure explained the observed simultaneous removal of COD and NH4[+]-N in the AF-FBR.}, } @article {pmid32573275, year = {2020}, author = {Díaz, MA and González, SN and Alberto, MR and Arena, ME}, title = {Human probiotic bacteria attenuate Pseudomonas aeruginosa biofilm and virulence by quorum-sensing inhibition.}, journal = {Biofouling}, volume = {36}, number = {5}, pages = {597-609}, doi = {10.1080/08927014.2020.1783253}, pmid = {32573275}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Humans ; *Probiotics ; *Pseudomonas aeruginosa ; Quorum Sensing/*drug effects ; Virulence ; Virulence Factors ; }, abstract = {This work investigated chloroform extracts from culture supernatants of two human probiotic bacteria, Lactobacillus casei CRL 431 and Lactobacillus acidophilus CRL 730 for the production of virulence factors and quorum sensing (QS) interference against three Pseudomonas aeruginosa strains. Both extracts inhibited biofilm biomass (up to 50%), biofilm metabolic activity (up to 39%), the production of the enzyme elastase (up to 63%) and pyocyanin (up to 77%), and decreased QS, without presenting any antibacterial acgivity. In addition, the chloroform extracts of both strains disrupted preformed biofilms of the three strains of P. aeruginosa analyzed (up to 40%). GC-MS analysis revealed that the major compounds detected in the bioactive extracts were four diketopiperazines. This study suggests that the metabolites of L. casei and L. acidophilus could be a promising alternative to combat the pathogenicity of P. aeruginosa.}, } @article {pmid32571216, year = {2020}, author = {Szerencsés, B and Igaz, N and Tóbiás, Á and Prucsi, Z and Rónavári, A and Bélteky, P and Madarász, D and Papp, C and Makra, I and Vágvölgyi, C and Kónya, Z and Pfeiffer, I and Kiricsi, M}, title = {Size-dependent activity of silver nanoparticles on the morphological switch and biofilm formation of opportunistic pathogenic yeasts.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {176}, pmid = {32571216}, issn = {1471-2180}, support = {GINOP-2.3.2-15-2016-00035//Hungarian Government and European Union/International ; GINOP-2.3.2-15-2016-00038//Hungarian Goverment and European Union/International ; UNKP-18-3-I-SZTE-42//Hungarian Ministry of Technology and Innovation/International ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*growth & development ; Cell Line ; Dynamic Light Scattering ; Fungi/drug effects/pathogenicity/*physiology ; Humans ; Hyphae/drug effects ; Keratinocytes/*cytology/drug effects/microbiology ; Metal Nanoparticles ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Particle Size ; Silver/chemistry/*pharmacology ; }, abstract = {BACKGROUND: Dimorphism and biofilm formation are important virulence factors of some opportunistic human pathogenic yeasts. Such species commensally colonize skin or mucosal surfaces generally in yeast form, but under particular circumstances, convert into virulent hyphae and disseminate internal organs or cause mucocutaneous infections. The yeast-to-hypha shape-conversion promotes the development of a biofilm, a thick extracellular matrix with sessile cells within. The biofilm is capable to prevent the penetration of antifungal drugs, rendering the surviving biofilm-resident cells intrinsic sources of recurrent infections. The aim of this study was to evaluate the ability of silver nanoparticles (AgNPs) to attenuate the morphological switch and biofilm formation of several opportunistic pathogenic yeasts and to determine whether this feature depends on the nanoparticle size.

RESULTS: AgNPs in three different sizes were prepared by chemical reduction approach and characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and dynamic light scattering. The antifungal activity was evaluated by the microdilution method, the inhibitory capacity on biofilm formation and the biofilm degradation ability of differently sized AgNPs was assessed by viability assay. The morphological state of opportunistic pathogenic yeast cells in monoculture and in co-culture with human keratinocytes in the presence of AgNPs was examined by flow cytometry and scanning electron microscopy. All the three AgNPs inhibited the growth of the examined opportunistic pathogenic yeasts, nevertheless, AgNPs with the smallest diameter exhibited the most prominent toxic activities. AgNPs attenuated the biofilm formation in a nanoparticle size-dependent manner; however, their biofilm destruction capacity was negligible. AgNPs with the smallest size exerted the most significant effect on suppressing the morphological change of pathogens in monoculture as well as in a co-culture with keratinocytes.

CONCLUSIONS: Our results confirm that AgNPs are capable to hinder yeast-to-hypha morphological conversion and biofilm formation of opportunistic pathogens and this biological effect of AgNPs is size-dependent.}, } @article {pmid32570785, year = {2020}, author = {Jeon, BK and Lee, CH and Kim, AR and Han, SH and Kim, HJ and Antonson, SA and Kim, SY}, title = {Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {12}, pages = {}, pmid = {32570785}, issn = {1996-1944}, support = {2017M3A9E4047246//National Research Foundation of Korea/ ; NRF-2018R1A5A2024418//National Research Foundation of Korea/ ; }, abstract = {Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite-dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.}, } @article {pmid32570081, year = {2020}, author = {Zhao, L and Wang, Z and Ren, HY and Nan, J and Chen, C and Ren, NQ}, title = {Improving biogas upgrading and liquid chemicals production simultaneously by a membrane biofilm reactor.}, journal = {Bioresource technology}, volume = {313}, number = {}, pages = {123693}, doi = {10.1016/j.biortech.2020.123693}, pmid = {32570081}, issn = {1873-2976}, mesh = {Biofilms ; *Biofuels ; *Bioreactors ; Carbon Dioxide ; Hydrogen ; Methane ; }, abstract = {In this study, a novel membrane biofilm reactor (MBfR) was developed for simultaneously biogas upgrading and liquid chemicals production. With external hydrogen supplied from inside of the gas permeable hollow fiber of the MBfR, CO2 in biogas could be captured via a biological process as liquid chemicals and simultaneously producing high-purity methane. Continuous operation of MBfR further confirmed that higher solubilized hydrogen was favorably affecting acetate and ethanol titer and rate, and methane purity. Moreover, by retaining biomass on the outer surface of hollow fiber, the highest biogas purity (96.7%) and acetate and ethanol production rates (37.8 and 13.5 mmol L[-1]d[-1]) were achieved at a hydraulic retention time of 2.0 d. Meanwhile, the CO2 and hydrogen conversion efficiency reached to the maximum of 93.8% and 98.1%, respectively. The findings obtained can pave a new way for efficient liquid chemical production and biogas upgrading with both economic and environmental benefits.}, } @article {pmid32569817, year = {2020}, author = {Vargas-Straube, MJ and Beard, S and Norambuena, R and Paradela, A and Vera, M and Jerez, CA}, title = {High copper concentration reduces biofilm formation in Acidithiobacillus ferrooxidans by decreasing production of extracellular polymeric substances and its adherence to elemental sulfur.}, journal = {Journal of proteomics}, volume = {225}, number = {}, pages = {103874}, doi = {10.1016/j.jprot.2020.103874}, pmid = {32569817}, issn = {1876-7737}, mesh = {Acidithiobacillus ; Bacterial Proteins ; Biofilms ; *Copper ; *Extracellular Polymeric Substance Matrix ; Sulfur ; }, abstract = {Acidithiobacillus ferrooxidans is an acidophilic bacterium able to grow in environments with high concentrations of metals. It is a chemolithoautotroph able to form biofilms on the surface of solid minerals to obtain its energy. The response of both planktonic and sessile cells of A. ferrooxidans ATCC 23270 grown in elemental sulfur and adapted to high copper concentration was analyzed by quantitative proteomics. It was found that 137 proteins varied their abundance when comparing both lifestyles. Copper effllux proteins, some subunits of the ATP synthase complex, porins, and proteins involved in cell wall modification increased their abundance in copper-adapted sessile lifestyle cells. On the other hand, planktonic copper-adapted cells showed increased levels of proteins such as: cupreredoxins involved in copper cell sequestration, some proteins related to sulfur metabolism, those involved in biosynthesis and transport of lipopolysaccharides, and in assembly of type IV pili. During copper adaptation a decreased formation of biofilms was measured as determined by epifluorescence microscopy. This was apparently due not only to a diminished number of sessile cells but also to their exopolysaccharides production. This is the first study showing that copper, a prevalent metal in biomining environments causes dispersion of A. ferrooxidans biofilms. SIGNIFICANCE: Copper is a metal frequently found in high concentrations at mining environments inhabitated by acidophilic microorganisms. Copper resistance determinants of A. ferrooxidans have been previously studied in planktonic cells. Although biofilms are recurrent in these types of environments, the effect of copper on their formation has not been studied so far. The results obtained indicate that high concentrations of copper reduce the capacity of A. ferrooxidans ATCC 23270 to form biofilms on sulfur. These findings may be relevant to consider for a bacterium widely used in copper bioleaching processes.}, } @article {pmid32569709, year = {2020}, author = {Kotian, A and Aditya, V and Jazeela, K and Karunasagar, I and Karunasagar, I and Deekshit, VK}, title = {Effect of bile on growth and biofilm formation of non-typhoidal salmonella serovars isolated from seafood and poultry.}, journal = {Research in microbiology}, volume = {171}, number = {5-6}, pages = {165-173}, doi = {10.1016/j.resmic.2020.06.002}, pmid = {32569709}, issn = {1769-7123}, mesh = {Animals ; *Bile ; Biofilms/*growth & development ; Cellulose/biosynthesis ; Food Microbiology ; Poultry/*microbiology ; Salmonella/*growth & development/isolation & purification ; Seafood/*microbiology ; }, abstract = {Bacterial cells adopt various strategies to adapt themselves in diverse environmental conditions. Salmonella is one such bacteria with diverse mechanisms to survive, replicate and infect in wide host range. This study aims at investigating the biofilm-forming ability of multidrug-resistant and sensitive Salmonella serovars on exposure to bile. Antibiogram of all the isolates was determined by disk diffusion method and their biofilm-forming ability in the presence or absence of bile was assessed by microtiter plate assay. Biofilm results were validated by calcofluor, Congo red plate and test tube method. Few isolates were selected for further study of their expression of biofilm related genes on exposure to bile using real time PCR. Among the 59 isolates of Salmonella isolated from seafood and poultry, 30 isolates were multi-drug resistant (MDR). Under control conditions, 57% (n = 25) of the serovars were able to form biofilm. While, 86% (n = 51) of the serovars produced biofilm in the presence of bile. The relative gene expression study of the selected serovars for 8 different genes showed a striking difference in the expression levels, supporting the hypothesis that the presence of bile triggers biofilm formation in food associated strains of non-typhoidal Salmonella by upregulation of genes involved in biofilm production.}, } @article {pmid32569268, year = {2020}, author = {Foster, CE and Kok, M and Flores, AR and Minard, CG and Luna, RA and Lamberth, LB and Kaplan, SL and Hulten, KG}, title = {Adhesin genes and biofilm formation among pediatric Staphylococcus aureus isolates from implant-associated infections.}, journal = {PloS one}, volume = {15}, number = {6}, pages = {e0235115}, pmid = {32569268}, issn = {1932-6203}, mesh = {Adhesins, Bacterial/*genetics ; Biofilms/*growth & development ; Child ; *Genes, Bacterial ; Humans ; Prosthesis-Related Infections/*genetics/*microbiology ; Skin/pathology ; Soft Tissue Infections/genetics/microbiology ; Staphylococcus aureus/*genetics/*isolation & purification ; }, abstract = {BACKGROUND: Microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) facilitate Staphylococcus aureus adherence to host tissue. We hypothesized that S. aureus isolates from implant-associated infections (IAIs) would differ in MSCRAMM profile and biofilm formation in vitro compared to skin and soft tissue infection (SSTI) isolates.

METHODS: Pediatric patients and their isolates were identified retrospectively. IAI and SSTI isolates were matched (1:4). Pulsed field gel electrophoresis was performed to group isolates as USA300 vs. non-USA300. Whole genome sequencing was performed and raw sequence data were interrogated for presence of MSCRAMMs (clfA, clfB, cna, ebh, efb, fnbpA, fnbpB, isdA, isdB, sdrC, sdrD, sdrE), biofilm-associated (icaA,D,B,C), and Panton-Valentine leukocidin (lukSF-PV) genes, accessory gene regulator group, and multilocus sequence types. In vitro biofilm formation was assessed for 47 IAI and 47 SSTI isolates using a microtiter plate assay. Conditional logistic regression was performed for analysis of matched data (STATA11, College Station, TX).

RESULTS: Forty-seven IAI and 188 SSTI isolates were studied. IAI isolates were more often methicillin susceptible S. aureus and non-USA300 vs. SSTI isolates [34 (72%) vs. 79 (42%), p = 0.001 and 38 (81%) vs. 57 (30%) p <0.001, respectively]. Greater than 98% of isolates carried clfA, clfB, efb, isdA, isdB, and icaA,D,B,C while cna was more frequently found among IAI vs. SSTI isolates (p = 0.003). Most isolates were strong biofilm producers.

CONCLUSIONS: S. aureus IAI isolates were significantly more likely to be MSSA and non-USA300 than SSTI isolates. Carriage of MSCRAMMs and biofilm formation did not differ significantly between isolates. Evaluation of genetic polymorphisms and gene expression profiles are needed to further delineate the role of adhesins in the pathogenesis of IAIs.}, } @article {pmid32566535, year = {2020}, author = {Azam, MW and Zuberi, A and Khan, AU}, title = {bolA gene involved in curli amyloids and fimbriae production in E. coli: exploring pathways to inhibit biofilm and amyloid formation.}, journal = {Journal of biological research (Thessalonike, Greece)}, volume = {27}, number = {}, pages = {10}, pmid = {32566535}, issn = {1790-045X}, abstract = {BACKGROUND: Biofilm formation is a complex phenomenon of bacterial cells, involved in several human infections. Its formation is regulated and controlled by several protein factors. The BolA-like proteins (bolA gene) are conserved in both prokaryotes and eukaryotes. The BolA protein is a transcription factor involved in bacterial cell motility and biofilm formation. This study was initiated to elucidate the role of the bolA gene in the curli biogenesis and amyloid production as well as to observe changes in the expression of fimH, a fimbriae gene.

METHODS: Knockdown mutants of Escherichia coli MG1655 bolA gene (bolA-KD) were generated using CRISPR interference. The results obtained, were validated through gene expression using RT-PCR, microscopic analysis and different biofilm and amyloid assays.

RESULTS: The bolA knockdown mutants showed a decrement in curli amyloid fibers, in fimbriae production and biofilm formation. We have also observed a reduction in EPS formation, eDNA production and extracellular protein content. Gene expression data showed that bolA downregulation caused the suppression of csgA and csgD of curli that led to the reduction in curli fiber and the amyloid formation and also the suppression of fimH, leading to the loss of fimbriae.

CONCLUSIONS: Curli fibers and fimbriae are found to be involved in biofilm formation leading to the pathogenicity of the bacterial cell. BolA is a conserved protein and is found to play a significant role in curli and fimbriae formation in E. coli. This study further proved that CRISPRi mediated suppression of the bolA gene leads to inhibition of biofilm formation through curli and fimbriae inhibition. Hence, it may be proposed as a possible target for intervention of biofilm mediated infections.}, } @article {pmid32566142, year = {2020}, author = {Hashimoto, A and Miyamoto, H and Kobatake, T and Nakashima, T and Shobuike, T and Ueno, M and Murakami, T and Noda, I and Sonohata, M and Mawatari, M}, title = {The combination of silver-containing hydroxyapatite coating and vancomycin has a synergistic antibacterial effect on methicillin-resistant Staphylococcus aureus biofilm formation.}, journal = {Bone & joint research}, volume = {9}, number = {5}, pages = {211-218}, pmid = {32566142}, issn = {2046-3758}, abstract = {AIMS: Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation.

METHODS: Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 10[6] or 43.0 (SD 8.4) x 10[5] colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 10[6]  or 72.0 (SD 4.2) x 10[5]  CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting.

RESULTS: Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment.

CONCLUSION: Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI.Cite this article: Bone Joint Res. 2020;9(5):211-218.}, } @article {pmid32564705, year = {2021}, author = {Higgins, M and Zhang, L and Ford, R and Brownlie, J and Kleidon, T and Rickard, CM and Ullman, A}, title = {The microbial biofilm composition on peripherally inserted central catheters: A comparison of polyurethane and hydrophobic catheters collected from paediatric patients.}, journal = {The journal of vascular access}, volume = {22}, number = {3}, pages = {388-393}, doi = {10.1177/1129729820932423}, pmid = {32564705}, issn = {1724-6032}, mesh = {Age Factors ; Bacteria/*growth & development/isolation & purification ; Biofilms/*growth & development ; Catheter-Related Infections/diagnosis/*microbiology ; Catheterization, Central Venous/adverse effects/*instrumentation ; Catheterization, Peripheral/adverse effects/*instrumentation ; Catheters, Indwelling/*microbiology ; Central Venous Catheters/*microbiology ; Child ; Female ; Humans ; Hydrophobic and Hydrophilic Interactions ; Male ; *Polyurethanes ; Time Factors ; }, abstract = {BACKGROUND: Peripherally inserted central catheters are susceptible to microbial colonisation and subsequent biofilm formation, leading to central line-associated bloodstream infection, a serious peripherally inserted central catheter-related complication. Next-generation peripherally inserted central catheter biomaterials, such as hydrophobic materials (e.g. Endexo[®]), may reduce microbial biofilm formation or attachment, consequently reducing the potential for central line-associated bloodstream infection.

METHODS: Within a randomised controlled trial, culture-dependent and culture-independent methods were used to determine if the biomaterials used in traditional polyurethane peripherally inserted central catheters and hydrophobic peripherally inserted central catheters impacted microbial biofilm composition. This study also explored the impact of other clinical characteristics including central line-associated bloodstream infection, antibiotic therapy and dwell time on the microbial biofilm composition of peripherally inserted central catheters.

RESULTS: From a total of 32 patients, one peripherally inserted central catheter was determined to be colonised with Staphylococcus aureus, and on further analysis, the patient was diagnosed with central line-associated bloodstream infection. All peripherally inserted central catheters (n = 17 polyurethane vs n = 15 hydrophobic) were populated with complex microbial communities, including peripherally inserted central catheters considered non-colonised. The two main microbial communities observed included Staphylococcus spp., dominant on the colonised peripherally inserted central catheter, and Enterococcus, dominant on non-colonised peripherally inserted central catheters. Both the peripherally inserted central catheter biomaterial design and antibiotic therapy had no significant impact on microbial communities. However, the diversity of microbial communities significantly decreased with dwell time.

CONCLUSION: More diverse pathogens were present on the colonised peripherally inserted central catheter collected from the patient with central line-associated bloodstream infection. Microbial biofilm composition did not appear to be affected by the design of peripherally inserted central catheter biomaterials or antibiotic therapy. However, the diversity of the microbial communities appeared to decrease with dwell time.}, } @article {pmid32564255, year = {2020}, author = {Tak, S and Tiwari, A and Vellanki, BP}, title = {Correction to: Identification of emerging contaminants and their transformation products in a moving bed biofilm reactor (MBBR)-based drinking water treatment plant around River Yamuna in India.}, journal = {Environmental monitoring and assessment}, volume = {192}, number = {7}, pages = {445}, doi = {10.1007/s10661-020-08381-4}, pmid = {32564255}, issn = {1573-2959}, abstract = {The original version of this article unfortunately contains mistakes introduced during the production phase. Figures 7, 8, and 10 were incorrectly captured.}, } @article {pmid32562967, year = {2020}, author = {Zhang, L and Fu, G and Zhang, Z}, title = {Long-term stable and energy-neutral mixed biofilm electrode for complete nitrogen removal from high-salinity wastewater: Mechanism and microbial community.}, journal = {Bioresource technology}, volume = {313}, number = {}, pages = {123660}, doi = {10.1016/j.biortech.2020.123660}, pmid = {32562967}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Electrodes ; *Microbiota ; Nitrification ; Nitrogen ; Salinity ; *Wastewater ; }, abstract = {The steady mixed biofilm electrode (MBE) was investigated for the removal of nitrogen from mustard tuber wastewater. Results showed that complete nitrogen removal occurred over a wide initial chemical oxygen demand (COD)/total nitrogen (TN) ratio ranging from 2.8 to 9.8 using MBE. MBE revealed broad-spectrum applicability for the treatment of high-salinity wastewater containing different forms of nitrogen. Bio-electrochemical process, in-situ heterotrophic nitrogen reduction, ammonia stripping, nitrogen assimilation, and endogenous denitrification coexisted for the removal of nitrogen. Batch activity tests and functional microorganism analysis confirmed that autotrophic/heterotrophic nitrification, anoxic/aerobic denitrification, and nitrogen bio-electrochemical reduction cooperated to achieve efficient nitrogen conversion. More importantly, the analysis of the preliminary energy balance demonstrated that MBE was self-sustaining. The long-term operation stability of MBE was of great importance for its practical application. The results provided herein offer new insights into bioelectrochemical nitrogen removal and resource treatment of high-salinity wastewater.}, } @article {pmid32562809, year = {2020}, author = {Moralez, AP and Perini, HF and Paulo, EA and Furlaneto-Maia, L and Furlaneto, MC}, title = {Effect of phenotypic switching on biofilm traits in Candida tropicalis.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104346}, doi = {10.1016/j.micpath.2020.104346}, pmid = {32562809}, issn = {1096-1208}, mesh = {Animals ; Biofilms ; *Candida tropicalis/genetics ; *Moths ; Phenotype ; Virulence ; }, abstract = {Candida tropicalis can undergo multiple forms of phenotypic switching. We have reported a switching system in C. tropicalis that is associated with changes in virulence attributes. We aimed to assess biofilm formation by distinct switch states of C. tropicalis and evaluate whether their sessile cells exhibit altered virulence traits. C. tropicalis strains included the parental phenotype (a clinical isolate) and four switch phenotypes (crepe, rough, revertant of crepe and revertant of rough). Biofilm formation and adhesion capability of sessile cells on polystyrene were assessed through quantification of total biomass. Filamentous forms were characterized by direct counting of sessile cells. A virulence assay was conducted using the Galleria mellonella infection model. Switch variants (crepe and rough) and their revertant counterparts produced higher biofilm biomass (P < 0.05) than the parental strain. Additionally, filamentous forms were enriched among sessile cells of switched strains compared to those observed for sessile cells of the parental strain, with the exception of the revertant of rough. Sessile cells of switched strains showed higher adhesion to polystyrene compared to the parental strain. Sessile cells of the crepe variant and its revertant strain (RC) exhibited higher virulence against G. mellonella larvae than sessile cells of the parental strain. Our findings indicate that switching events in C. tropicalis affect biofilm development and that sessile cells of distinct switch states may exhibit increased adhesion ability and enhanced virulence towards G. mellonella larvae.}, } @article {pmid32561585, year = {2020}, author = {Cai, W and Liu, W and Wang, B and Yao, H and Guadie, A and Wang, A}, title = {Semiquantitative Detection of Hydrogen-Associated or Hydrogen-Free Electron Transfer within Methanogenic Biofilm of Microbial Electrosynthesis.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {17}, pages = {}, pmid = {32561585}, issn = {1098-5336}, mesh = {Archaea/metabolism/*physiology ; Bacteria/metabolism ; *Bacterial Physiological Phenomena ; *Biofilms ; Electron Transport ; Hydrogen/*metabolism ; Methane/*metabolism ; }, abstract = {Hydrogen-entangled electron transfer has been verified as an important extracellular pathway of sharing reducing equivalents to regulate biofilm activities within a diversely anaerobic environment, especially in microbial electrosynthesis systems. However, with a lack of useful methods for in situ hydrogen detection in cathodic biofilms, the role of hydrogen involvement in electron transfer is still debatable. Here, a cathodic biofilm was constructed in CH4-produced microbial electrosynthesis reactors, in which the hydrogen evolution dynamic was analyzed to confirm the presence of hydrogen-associated electron transfer near the cathode within a micrometer scale. Fluorescent in situ hybridization images indicated that a colocalized community of archaea and bacteria developed within a 58.10-μm-thick biofilm at the cathode, suggesting that the hydrogen gradient detected by the microsensor was consumed by the collaboration of bacteria and archaea. Coupling of a microsensor and cyclic voltammetry test further provided semiquantitative results of the hydrogen-associated contribution to methane generation (around 21.20% ± 1.57% at a potential of -0.5 V to -0.69 V). This finding provides deep insight into the mechanism of electron transfer in biofilm on conductive materials.IMPORTANCE Electron transfer from an electrode to biofilm is of great interest to the fields of microbial electrochemical technology, bioremediation, and methanogenesis. It has a promising potential application to boost more value-added products or pollutant degradation. Importantly, the ability of microbes to obtain electrons from electrodes and utilize them brings new insight into direct interspecies electron transfer during methanogenesis. Previous studies verified the direct pathway of electron transfer from the electrode to a pure-culture bacterium, but it was rarely reported how the methanogenic biofilm of mixed cultures shares electrons by a hydrogen-associated or hydrogen-free pathway. In the current study, a combination method of microsensor and cyclic voltammetry successfully semiquantified the role of hydrogen in electron transfer from an electrode to methanogenic biofilm.}, } @article {pmid32560415, year = {2020}, author = {Pannella, G and Lombardi, SJ and Coppola, F and Vergalito, F and Iorizzo, M and Succi, M and Tremonte, P and Iannini, C and Sorrentino, E and Coppola, R}, title = {Effect of Biofilm Formation by Lactobacillus plantarum on the Malolactic Fermentation in Model Wine.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {32560415}, issn = {2304-8158}, abstract = {Biofilm life-style of Lactobacillus plantarum (L. plantarum) strains was evaluated in vitro as a new and suitable biotechnological strategy to assure L-malic acid conversion in wine stress conditions. Sixty-eight L. plantarum strains isolated from diverse sources were assessed for their ability to form biofilm in acid (pH 3.5 or 3.2) or in ethanol (12% or 14%) stress conditions. The effect of incubation times (24 and 72 h) on the biofilm formation was evaluated. The study highlighted that, regardless of isolation source and stress conditions, the ability to form biofilm was strain-dependent. Specifically, two clusters, formed by high and low biofilm producer strains, were identified. Among high producer strains, L. plantarum Lpls22 was chosen as the highest producer strain and cultivated in planktonic form or in biofilm using oak supports. Model wines at 12% of ethanol and pH 3.5 or 3.2 were used to assess planktonic and biofilm cells survival and to evaluate the effect of biofilm on L-malic acid conversion. For cells in planktonic form, a strong survival decay was detected. In contrast, cells in biofilm life-style showed high resistance, assuring a prompt and complete L-malic acid conversion.}, } @article {pmid32560399, year = {2020}, author = {Fu, Y and An, Q and Cheng, Y and Yang, Y and Wang, L and Zhang, H and Ge, Y and Li, D and Zhang, Y}, title = {A Textile Pile Debridement Material Consisting of Polyester Fibers for in Vitro Removal of Biofilm.}, journal = {Polymers}, volume = {12}, number = {6}, pages = {}, pmid = {32560399}, issn = {2073-4360}, support = {51803095//National Natural Science Foundation of China/ ; BK20190927//Natural Science Foundation of Jiangsu Province/ ; 2019Z104//Postdoctoral Daily Program of Jiangsu Province/ ; MS12018005//Nantong Science and Technology Project/ ; W201905//Open Project Program of Key Laboratory of Textile Science & Technology (Donghua University), Ministry of Education/ ; }, abstract = {Biofilms formed on skin wound lead to inflammation and a delay of healing. In the present work, a novel textile pile debridement material was prepared and treated by plasma. Samples before and after plasma treatment were characterized by a series of methods, including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water uptake capacity. Besides, mechanical, coagulation, and in vitro biofilm removal performances of the textile pile debridement material were evaluated, with a medical gauze as a control. The results demonstrate that the plasma treatment produced corrosions and oxygen-containing polar groups on the fiber surface, offering an enhanced water uptake capacity of the textile pile debridement material. In addition, compressive tests certify the mechanical performances of the textile pile debridement material in both dry and wet conditions. The results from a kinetic clotting time test suggest a favorable ability to promote blood coagulation. Furthermore, the results of an MTT cell viability assay, SEM, and confocal laser scanning microscopy (CLSM) illustrate that the textile pile debridement material demonstrates a more superior in vitro biofilm removal performance than medical gauze. All of these characterizations suggest that the textile pile debridement material can offer a feasible application for clinical wound debridement.}, } @article {pmid32560208, year = {2020}, author = {Singh, P and Pandit, S and Mokkapati, V and Garnæs, J and Mijakovic, I}, title = {A Sustainable Approach for the Green Synthesis of Silver Nanoparticles from Solibacillus isronensis sp. and Their Application in Biofilm Inhibition.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {12}, pages = {}, pmid = {32560208}, issn = {1420-3049}, mesh = {Biofilms/*drug effects/growth & development ; Escherichia coli/*physiology ; *Green Chemistry Technology ; Metal Nanoparticles/*chemistry ; Planococcaceae/*chemistry ; Pseudomonas aeruginosa/*physiology ; *Silver/chemistry/pharmacology ; }, abstract = {The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields and facile synthesis of nanoparticles. The green synthesis provides the coating or capping of biomolecules on nanoparticles surface, which confer their biological activity. In this study, we report green synthesis of silver nanoparticles (AgNPs) by an environmental isolate; named as AgNPs1, which showed 100% 16S rRNA sequence similarity with Solibacillus isronensis. UV/visible analysis (UV/Vis), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stable nature of nanoparticles was studied by thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS). Further, these nanoparticles were tested for biofilm inhibition against Escherichia coli and Pseudomonas aeruginosa. The AgNPs showed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.12 µg/mL and 6.25 µg/mL for E. coli, and 1.56 µg/mL and 3.12 µg/mL for P. aeruginosa, respectively.}, } @article {pmid32559664, year = {2020}, author = {Li, K and Qian, J and Wang, P and Wang, C and Lu, B and Jin, W and He, X and Tang, S and Zhang, C and Gao, P}, title = {Responses of freshwater biofilm formation processes (from colonization to maturity) to anatase and rutile TiO2 nanoparticles: Effects of nanoparticles aging and transformation.}, journal = {Water research}, volume = {182}, number = {}, pages = {115953}, doi = {10.1016/j.watres.2020.115953}, pmid = {32559664}, issn = {1879-2448}, mesh = {Biofilms ; Fresh Water ; *Nanoparticles ; *Titanium ; }, abstract = {Most of the current studies on the toxicology of pristine nanoparticles (NPs) are environmentally irrelevant, because their ''aging'' process accompanied by the physicochemical transformation is inevitable in the environment. Considering aging phenomenon will gain a better understanding of the toxicity and fate of NPs in the environment. Here, we focused on the physicochemical transformation of anatase-NPs (TiO2-A) and rutile-NPs (TiO2-R) after 90 days of aging and investigated the responses of freshwater biofilm formation to the stress changes of naturally aged TiO2-NPs (aTiO2-NPs). We found that after aging, the TiO2-NPs underwent sophisticated physicochemical transformations in the original morphology and microstructure owing to organic and crystal salts inclusions, such as energy band changes and the formation of Ti[3+] on the NPs surfaces. These comprehensive transformations increased the stability of NPs in the exposed suspension. However, the physicochemical transformations were crystal-forms-dependent, and aging did not change the crystal structure and crystallinity. Interestingly, compared to pristine NPs, aTiO2-NPs showed much lower cytotoxicity and had the weaker ability to promote or inhibit the biofilm formation (p < 0.05) owing to the passivation of photoactivity caused by the comprehensive effect of the inclusions, especially for aTiO2-A. Regardless of aging or not of crystal forms, responses of biofilm formation were exposure-concentration-dependent, namely low concentration promotion (0.1 mg/L) and high concentration inhibition (10 mg/L), e.g., role transition of the pioneers (algae or bacteria) in initial colonization, extracellular polymeric substances (EPS) secretion and compositions of development stages with polysaccharide (PS)-rich and protein (PRO)-rich stages, and biomass and cell activity at different depths of mature biofilms. The reactive oxygen species (ROS) induced by TiO2-NPs showed typical hormesis. The changing trends of the autoinducers (c-di-GMP and quorum sensing signals including AHL and AI-2) were highly consistent with the growth stages of biofilms and were stimulated or suppressed by TiO2-NPs. The NPs crystal-dependently changed the microorganism community structures, while the UPGMA clustering of bacteria was based on the growth stages of the biofilms. The toxic mechanisms revealed that photoactivity and nanoscale retention of particles are the main reasons for the differences in the ecological stress capacity of four kinds of TiO2-NPs. Aging reduced characteristic differences of two pristine NPs and even reversed their relative stresses levels (p > 0.05). However, the toxicity of high-concentration aTiO2-NPs (10 mg/L) remained serious in a water environment. This study provides a better understanding for the water environmental risks evaluation and policy control of nanoparticles, that is, the effect of time aging has to be considered.}, } @article {pmid32559542, year = {2020}, author = {Schwarz, A and Suárez, JI and Aybar, M and Nancucheo, I and Martínez, P and Rittmann, BE}, title = {A membrane-biofilm system for sulfate conversion to elemental sulfur in mining-influenced waters.}, journal = {The Science of the total environment}, volume = {740}, number = {}, pages = {140088}, doi = {10.1016/j.scitotenv.2020.140088}, pmid = {32559542}, issn = {1879-1026}, mesh = {Biofilms ; *Bioreactors ; Mining ; Oxidation-Reduction ; *Sulfates ; Sulfur ; }, abstract = {A system of two membrane biofilm reactors (MBfRs) was tested for the conversion of sulfate (1.5 g/L) in mining-process water into elemental sulfur (S[0]) particles. Initially, a H2-based MBfR reduced sulfate to sulfide, and an O2-based MBfR then oxidized sulfide to S[0]. Later, the two MBfRs were coupled by a recirculation flow. Surface loading, reactor-coupling configuration, and substrate-gas pressure exerted important controls over performance of each MBfR and the coupled system. Continuously recirculating the liquid between the H2-based MBfR and the O2-based MBfR, compared to series operation, avoided the buildup of sulfide and gave overall greater sulfate removal (99% vs 62%) and production of S[0] (61% vs 54%). The trade-off was that recirculation coupling demanded greater delivery of H2 and O2 (in air) due to the establishment of a sulfur cycle catalyzed by Sulfurospirillum spp., which had an average abundance of 46% in the H2-based MBfR fibers and 62% in the O2-based MBfR fibers at the end of the experiments. Sulfate-reducing bacteria (Desulfovibrio and Desulfomicrobium) and sulfur-oxidizing bacteria (Thiofaba, Thiomonas, Acidithiobacillus and Sulfuricurvum) averaged only 22% and 11% in the H2-based MBfR and O2-based MBfR fibers, respectively. Evidence suggests that the undesired Sulfurospirillum species, which reduce S[0] to sulfide, can be suppressed by increasing sulfate-surface loading and H2 pressure.}, } @article {pmid32558324, year = {2020}, author = {Llama-Palacios, A and Potupa, O and Sánchez, MC and Figuero, E and Herrera, D and Sanz, M}, title = {Proteomic analysis of Fusobacterium nucleatum growth in biofilm versus planktonic state.}, journal = {Molecular oral microbiology}, volume = {35}, number = {4}, pages = {168-180}, doi = {10.1111/omi.12303}, pmid = {32558324}, issn = {2041-1014}, mesh = {*Biofilms ; *Fusobacterium nucleatum ; Humans ; *Plankton ; Proteomics ; Virulence ; }, abstract = {Fusobacterium nucleatum is isolated from both supra- and sub-gingival dental biofilms in humans and has been implicated in the aetiology of periodontitis. Also, this bacterium plays an important role in serious infections in other parts of the body. The aim of this investigation was to study the protein differential expression of F. nucleatum when growing on biofilm, compared to planktonic state, using proteomic analysis by the 2D-DIGE™ system. In all, 68 proteins were differentially expressed during biofilm growth (1.5-fold, p < .05), being 20 downexpressed and 31 overexpressed. The repressed proteins belonged to metabolism, biosynthesis and were outer membrane proteins (OMPs); and overexpressed were proteins involved in metabolism, transcription, translation, transport and proteins with unknown function. Also, of the seven enzymes that regulate the synthesis of butyrate, six of them were differentially expressed (overexpressed and downexpressed) when the bacteria were forming biofilms. The enzymatic activities of two of the enzymes in the butyrate pathway were analysed when the bacteria were growing in biofilms or in planktonic growth. All these results confirmed that this metabolic pathway is important in the formation of the biofilm of F. nucleatum and in its pathogenicity, both in the oral cavity and in other locations of the body.}, } @article {pmid32557120, year = {2020}, author = {Huang, X and Zheng, M and Yi, Y and Patel, A and Song, Z and Li, Y}, title = {Inhibition of berberine hydrochloride on Candida albicans biofilm formation.}, journal = {Biotechnology letters}, volume = {42}, number = {11}, pages = {2263-2269}, pmid = {32557120}, issn = {1573-6776}, support = {17TD0013//Education Department of Sichuan Province/ ; JSZX2018006//Chengdu University of Traditional Chinese Medicine (CN)/ ; }, mesh = {Antifungal Agents/*pharmacology ; Berberine/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/*physiology ; DNA-Binding Proteins/genetics ; Down-Regulation ; Fungal Proteins/*genetics ; Gene Expression Profiling ; Gene Expression Regulation, Fungal/drug effects ; Membrane Glycoproteins/genetics ; Microbial Sensitivity Tests ; Microbial Viability ; Transcription Factors/genetics ; }, abstract = {OBJECTIVE: This study aimed to investigate the inhibitory effect of berberine hydrochloride (BH) on Candida albicans (C.albicans) ATCC10231 biofilm formation.

RESULTS: This paper found a positive correlation between the concentration of BH and its inhibitory effect on the cellular activity of early biofilms because we found that 128 and 32 μg/mL BH significantly inhibited biofilm formation (P < 0.05). BH significantly inhibited the cellular activity in early biofilms, destroyed the microscopic morphology of C.albicans and reduced the thickness of the biofilm. Both 128 and 32 μg/mL concentration solutions of BH significantly inhibited biofilm formation (P < 0.05). We found that the inhibitory effect of BH solution was positively correlated with its concentration and 128 μg/mL BH was better than 4 μg/mL fluconazole. Additionally, the results of RT-PCR indicated that 128 and 32 μg/mL BH inhibited the expression of EFG1, HWP1, ECE1, and ALS1 (P < 0.05).

CONCLUSION: The efficacy of BH in inhibiting the formation of C.albicans biofilm by killing the cells in the biofilm and destroying its structure; and the mechanism may be to down-regulate the expression of EFG1, HWP1, ECE1, and ALS1 in hyphae formation, thereby, retarding the morphological transformation of C. albicans.}, } @article {pmid32556007, year = {2020}, author = {Miranda, SLF and Damaceno, JT and Faveri, M and Figueiredo, LC and Soares, GMS and Feres, M and Bueno-Silva, B}, title = {In Vitro Antimicrobial Effect of Cetylpyridinium Chloride on Complex Multispecies Subgingival Biofilm.}, journal = {Brazilian dental journal}, volume = {31}, number = {2}, pages = {103-108}, doi = {10.1590/0103-6440202002630}, pmid = {32556007}, issn = {1806-4760}, mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; *Anti-Infective Agents, Local ; Biofilms ; Cetylpyridinium ; Chlorhexidine ; }, abstract = {Periodontopathogenic subgingival biofilm is the main etiological agent of periodontitis. Thus, a search for antimicrobials as adjuvant for periodontal treatment in the literature is intense. Cetylpyridinium chloride (CPC) is a well-known antimicrobial agent commonly used in mouthrinses. However, CPC effects on a complex biofilm model were not found over the literature. Therefore, the aim of this manuscript is to evaluate 0.075% CPC antimicrobial properties in a multispecies subgingival biofilm model in vitro. The subgingival biofilm composed by 31 species related to periodontitis was formed for 7 days, using the calgary device. The treatments with CPC and chlorhexidine (CHX) 0.12% (as positive control) were performed 2x/day, for 1 min, from day 3 until the end of experimental period, totaling 8 treatments. After 7 days of biofilm formation, biofilm metabolic activity was evaluated by a colorimetric reaction and biofilms microbial composition by DNA-DNA hybridization. Statistical analysis was performed using ANOVA with data transformed via BOX-COX followed by Dunnett post-hoc. Both CPC and CHX reduced biofilm metabolic activity in 60% and presented antimicrobial activity against 13 different species. Specifically, only CHX reduced levels of F.n. vicentii and P. gingivalis while only CPC reduced A. odontolyticus and A. israelli. CPC was as effective as CHX as antimicrobial through in vitro complex multispecies subgingival biofilm. However, future studies using in vivo models of experimental periodontal disease should be performed to prove such effect.}, } @article {pmid32554257, year = {2020}, author = {Subbiahdoss, G and Reimhult, E}, title = {Biofilm formation at oil-water interfaces is not a simple function of bacterial hydrophobicity.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {194}, number = {}, pages = {111163}, doi = {10.1016/j.colsurfb.2020.111163}, pmid = {32554257}, issn = {1873-4367}, mesh = {*Bacterial Adhesion ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; *Staphylococcus aureus ; *Staphylococcus epidermidis ; Water ; }, abstract = {Bacterial adsorption to interfaces is the initial step in biofilm formation. The mechanism of biofilm formation at liquid-liquid interfaces differs from the process of biofilm formation on solid-liquid interfaces. Until now, the former is not well understood. We study the bacterial adsorption and biofilm formation of three different bacteria, P. aeruginosa, S. aureus, and S. epidermidis at the n-decane-water interface, with focus on the relationship between bacteria wettability, excretion of biosurfactants, and biofilm formation. The adhesion capacity of these bacteria to hydrocarbons was characterized using the bacterial adherence to hydrocarbons test. We monitored the interfacial rheology of bacterial adsorption and biofilm formation at the interface over time using a drop shape analyzer and imaged the formed biofilms by using fluorescence and scanning electron microscopy. P. aeruginosa showed high adhesion capacity to hydrocarbons, while the adhesion capacity of both staphylococci was negligible. P. aeruginosa also showed rapid adsorption to the n-decane-water interface as measured by the rapid decrease in interfacial tension for the pure bacteria suspension. However, S. epidermidis, with a negligible hydrophobicity value, showed the most substantial reduction in interfacial tension and the formation of the most elastic biofilms at the oil-water interface. S. epidermidis accomplishes this by the secretion of biosurfactants. S. aureus did not form biofilms at the n-decane-water interface, in contrast to P. aeruginosa and S. epidermidis. We conclude that bacterial adsorption and biofilm formation at oil-water interfaces, in general, are not simple functions of cell hydrophobicity. Biosurfactant modification and metabolism of the interface also play essential roles.}, } @article {pmid32554017, year = {2020}, author = {Zhou, Y and Guo, B and Li, R and Zhang, L and Xia, S and Liu, Y}, title = {Treatment of grey water (GW) with high linear alkylbenzene sulfonates (LAS) content and carbon/nitrogen (C/N) ratio in an oxygen-based membrane biofilm reactor (O2-MBfR).}, journal = {Chemosphere}, volume = {258}, number = {}, pages = {127363}, doi = {10.1016/j.chemosphere.2020.127363}, pmid = {32554017}, issn = {1879-1298}, mesh = {Alkanesulfonic Acids/*analysis ; Biodegradation, Environmental ; Biofilms/drug effects/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Carbon/*analysis ; Membranes, Artificial ; Nitrogen/*analysis ; Oxygen/*chemistry ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*analysis ; }, abstract = {Grey water (GW) containing high levels of linear alkylbenzene sulfonates (LAS) can be a threat to the human health and organisms in the environment if not treated properly. Although aerobic treatment may achieve high GW treatment efficacy, conventional aeration can lead to serious foaming. Here, we firstly and systematically evaluated an oxygen-based membrane biofilm reactor (O2-MBfR) for its capacity to simultaneous remove organics and nitrogen from greywater with high LAS levels and carbon/nitrogen (C/N) ratios. After a five-day startup period, multifarious microorganisms formed multifunctional biofilms and the MBfR achieved high removal rates of chemical oxygen demand (COD), LAS, and total nitrogen (TN) of 88.4%, 95.6%, and 80%, respectively, with a hydraulic retention time of 7.86 h. Higher organics loading (5.53 g TCOD/m[2]-day) caused cell lysis and damaged the O2-MBfR system, leading to a discernible and continuous decline of the reactor performance. The O2-MBfR design completely eliminated foaming formation. LAS -biodegrading-rich genus containing Clostridium, Parvibaculum, Dechloromonas, Desulfovibrio, Mycobacterium, Pseudomonas, and Zoogloea enable the nearly complete removal of LAS even under high C/N conditions. Results demonstrated that the O2-MBfR technology is feasible for treating GW containing high LAS and C/N ratio, while remaining free of foaming formation, and at a low cost due to high O2 utilization rates.}, } @article {pmid32552790, year = {2020}, author = {Miao, W and Sheng, L and Yang, T and Wu, G and Zhang, M and Sun, J and Ainiwaer, A}, title = {The impact of flavonoids-rich Ziziphus jujuba Mill. Extract on Staphylococcus aureus biofilm formation.}, journal = {BMC complementary medicine and therapies}, volume = {20}, number = {1}, pages = {187}, pmid = {32552790}, issn = {2662-7671}, support = {Q2015-01-06//the Xinjiang traditional Chinese medicine new drug research and development projects/ ; 81660695//the National Natural Science Foundation of China/ ; 2-14-01//Xinjiang Tianshan talent projects/ ; qn2015jq005//Training project for outstanding young people in science and technology in the Xinjiang/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Flavonoids/*pharmacology ; Plant Extracts/*pharmacology ; Staphylococcus aureus/*drug effects ; Ziziphus/*chemistry ; }, abstract = {BACKGROUND: To evaluate the in vitro antibacterial effect of flavonoids-rich Ziziphus jujuba Mill. extract (FZM) against the formation of bacterial biofilms (BBFs) in Staphylococcus aureus.

RESULTS: FZM can effectively inhibit the formation of S. aureus biofilms in vitro. Morphological observation showed a decrease in both biofilm adhesion and thickness. Results of confocal laser scanning microscopy used to detect the thickness of the BBFs showed that FZM treatment reduced the thickness of the BBFs. Furthermore, after the Image-Pro Plus v.6.0 analysis of the fluorescence intensity, FZM treatment reduced the thickness of the BBFs as well as the proportion of green fluorescence. Scanning electron microscopy showed that FZM can disrupt the channels available for substance exchange in the biofilm, thus exposing the bacterial cells and damaging its three-dimensional structures.

CONCLUSION: FZM can inhibit biofilm formation, improve the bacterial pH environment, and eliminate the hydrophobic effect of reactive oxygen species and flavonoids.}, } @article {pmid32552165, year = {2020}, author = {Grønseth, T and Vestby, LK and Nesse, LL and von Unge, M and Silvola, JT}, title = {Bioactive glass S53P4 eradicates Staphylococcus aureus in biofilm/planktonic states in vitro.}, journal = {Upsala journal of medical sciences}, volume = {125}, number = {3}, pages = {217-225}, pmid = {32552165}, issn = {2000-1967}, mesh = {Biofilms/*drug effects ; *Glass ; Microbial Sensitivity Tests ; Plankton/*drug effects ; Staphylococcus aureus/*drug effects ; }, abstract = {Background: Increasing antimicrobial resistance to antibiotics is a substantial health threat. Bioactive glass S53P4 (BAG) has an antimicrobial effect that can reduce the use of antibiotics. The aim of this study was to evaluate the antimicrobial efficacy of BAG in vitro on staphylococci in biofilm and in planktonic form. Secondary aims were to investigate whether supernatant fluid primed from BAG retains the antibacterial capacity and if ciprofloxacin enhances the effect.Methods: BAG-S53P4 granules, <45 µm, primed in tryptic soy broth (TSB) were investigated with granules present in TSB (100 mg/mL) and after removal of granules (100, 200, and 400 mg/mL). The efficacy of BAG to eradicate Staphylococcus aureus biofilm in vitro was tested using 10 different clinical strains and 1 reference strain in three test systems: the biofilm-oriented antiseptic test based on metabolic activity, the biofilm bactericidal test based on culturing surviving bacteria, and confocal laser scanning microscopy (CLSM) combined with LIVE/DEAD staining.Results: Exposure to 48 h primed BAG granules (100 mg/mL) produced bactericidal effects in 11/11 strains (p = 0.001), and CLSM showed reduction of viable bacteria in biofilm (p = 0.001). Supernatant primed 14 days, 400 mg/mL, reduced metabolic activity (p < 0.001), showed bactericidal effects for 11/11 strains (p = 0.001), and CLSM showed fewer viable bacteria (p = 0.001). The supernatant primed for 48 h, or in concentrations lower than 400 mg/mL at 14 days, did not completely eradicate biofilm.Conclusion: Direct exposure to BAG granules, or primed supernatant fluid, effectively eradicated S. aureus in biofilm. The anti-biofilm effect is time- and concentration-dependent. When BAG had reached its full antimicrobial effect, ciprofloxacin had no additional effect.}, } @article {pmid32550510, year = {2020}, author = {Arata, Y and Oshima, T and Ikeda, Y and Kimura, H and Sako, Y}, title = {OP50, a bacterial strain conventionally used as food for laboratory maintenance of C. elegans, is a biofilm formation defective mutant.}, journal = {microPublication biology}, volume = {2020}, number = {}, pages = {}, pmid = {32550510}, issn = {2578-9430}, support = {P40 OD010440/OD/NIH HHS/United States ; }, } @article {pmid32549591, year = {2020}, author = {Nagar, N and Aswathanarayan, JB and Vittal, RR}, title = {Anti-quorum sensing and biofilm inhibitory activity of Apium graveolens L. oleoresin.}, journal = {Journal of food science and technology}, volume = {57}, number = {7}, pages = {2414-2422}, pmid = {32549591}, issn = {0022-1155}, abstract = {Apium graveolens L. (Apiaceae) is a dietary herb used as a spice, condiment and medicine. A. graveolens (Celery) has been studied for its antimicrobial property and for its application as flavours in food industry. The present study investigated the Apium graveolens oleoresin as an anti-quorum sensing and antibiofilm agent. The quorum sensing and biofilm inhibition study was carried out using biosensor strains Chromobacterium violaceum CV12472 and Pseudomonas aeruginosa PAO1. The MIC of celery oleoresin against C. violaceum CV12472 and P. aeruginosa PAO1 was 10 and 25% v/v, respectively. Inhibition of violacein and biofilm formation was tested at concentrations of oleoresins ranging from 1.56 and 50% v/v. The oleoresins showed a concentration dependent QS inhibitory activity and at sub-MIC of 6.25 and 12.5% v/v, the oleoresins significantly inhibited violacein production and biofilm formation (p < 0.05). Similarly, the celery oleoresin had significant QS modulatory effect on swimming, swarming and twitching motility in P. aeruginosa PAO1 at 12.5% v/v (p < 0.05). The major phytoconstituents present in celery oleoresin as analysed by GC-MS were eicosadiene, benzenemethanol and methyl ester which have not been previously reported. The findings suggest that celery has QS and biofilm inhibitory potential against gram negative pathogens and can find application as food intervention techniques.}, } @article {pmid32548895, year = {2020}, author = {Cai, Y and Wang, C and Chen, Z and Xu, Z and Li, H and Li, W and Sun, Y}, title = {Transporters HP0939, HP0497, and HP0471 participate in intrinsic multidrug resistance and biofilm formation in Helicobacter pylori by enhancing drug efflux.}, journal = {Helicobacter}, volume = {25}, number = {4}, pages = {e12715}, doi = {10.1111/hel.12715}, pmid = {32548895}, issn = {1523-5378}, support = {81471991//National Natural Science Foundation of China/ ; 81671978//National Natural Science Foundation of China/ ; 81772143//National Natural Science Foundation of China/ ; 81670486//National Natural Science Foundation of China/ ; 81374101//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*metabolism/pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial/*drug effects/genetics ; Gene Expression ; Helicobacter Infections/microbiology ; Helicobacter pylori/drug effects/genetics/isolation & purification/*physiology ; Humans ; Membrane Transport Proteins/genetics/*metabolism ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: The multidrug resistance of Helicobacter pylori is becoming an increasingly serious issue. It is therefore necessary to study the mechanism of multidrug resistance of H pylori. We have previously identified that the HP0939, HP0497, and HP0471 transporters affect the efflux of drugs from H pylori. As efflux pumps participate in bacterial multidrug resistance and biofilm formation, we hypothesized that these transporters could be involved in the multidrug resistance and biofilm formation of H pylori.

MATERIALS AND METHODS: We therefore constructed three knockout strains, Δhp0939, Δhp0497, and Δhp0471, and three high-expression strains, Hp0939[he] , Hp0497[he] , and Hp0471[he] , using the wild-type (WT) 26 695 strain of H pylori as the template. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of wild strains, knockout strains, and high-expression strains to amoxicillin, metronidazole, and other antibiotics were measured. The efflux capacity of high-expression strains and wild strains was compared by Hoechst 33 342 accumulation assay.

RESULTS: Determination of the MIC and MBC of the antibiotics revealed that the knockout strains were more sensitive to antibiotics, while the high-expression strains were less sensitive to antibiotics, compared to the WT. The ability of the high-expression strains to efflux drugs was significantly higher than that of the WT. We also induced H pylori to form biofilms, and observed that the knockout strains could barely form biofilms and were more sensitive to several antibiotics, compared to the WT. The mRNA expression of hp0939, hp0497, and hp0471 in the clinically sensitive and multidrug-resistant strains was determined, and it was found that these genes were highly expressed in the multidrug-resistant strains that were isolated from the clinics.

CONCLUSIONS: In this study, we found three transporters involved in intrinsic multidrug resistance of H pylori.}, } @article {pmid32548178, year = {2020}, author = {Chen, G and Liang, H}, title = {A novel c-di-GMP signal system regulates biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbial cell (Graz, Austria)}, volume = {7}, number = {6}, pages = {160-161}, doi = {10.15698/mic2020.06.720}, pmid = {32548178}, issn = {2311-2638}, abstract = {The bacterial second messenger cyclic-di-GMP (c-di-GMP) controls biofilm formation and other phenotypes relevant to pathogenesis. The human pathogen Pseudomonas aeruginosa encodes 17 diguanylate cyclase (DGCs) proteins which are required for c-di-GMP synthesis. Therefore, the c-di-GMP regulatory system in P. aeruginosa is highly sophisticated. SiaD, one of the DGC enzymes, is co-transcribed with SiaA/B/C and has been shown to be essential for bacterial aggregate formation in response to environmental stress. However, the detailed function of this operon remains unknown. In our recent paper (Chen et al., doi: 10.15252/embj.2019103412), we have demonstrated that the siaABCD operon encodes a signaling network that regulates biofilm and aggregate formation by modulating the enzymatic activity of SiaD. Among this signaling system, SiaC interaction with SiaD promotes the diguanylate cyclase activity of SiaD and subsequently facilities the intracellular c-di-GMP synthesis; SiaB is a unique protein kinase that phosphorylates SiaC, whereas SiaA phosphatase can dephosphorylate SiaC. The phosphorylation state of SiaC is critical for its interaction with SiaD, which will switch on or off the DGC activity of SiaD. This report unveils a novel signaling system that controls biofilm formation, which may provide a potential target for developing antimicrobial drugs.}, } @article {pmid32548095, year = {2020}, author = {Hamida, RS and Ali, MA and Goda, DA and Khalil, MI and Al-Zaban, MI}, title = {Novel Biogenic Silver Nanoparticle-Induced Reactive Oxygen Species Inhibit the Biofilm Formation and Virulence Activities of Methicillin-Resistant Staphylococcus aureus (MRSA) Strain.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {433}, pmid = {32548095}, issn = {2296-4185}, abstract = {Emerging antibiotic-resistant bacteria result in increased mortality and have negative economic impacts. It is necessary to discover new strategies to create alternative antibacterial agents that suppress the bacterial resistance mechanism and limit the spread of serious infectious bacterial diseases. Silver nanoparticles may represent a new medicinal agents as alternative antibiotics affect different bacterial mechanisms such as virulence and resistance. In addition to that of silver nitrate (AgNO3) and ampicillin, for the first time, the inhibitory effect of silver nanoparticles synthesized using Desertifilum sp. (D-SNPs) was evaluated against five pathogenic bacteria using the agar well diffusion method. Also, the influence of D-SNPs and AgNO3 on bacterial antioxidant and metabolic activities was studied. The antibacterial activity of D-SNPs and AgNO3 against methicillin-resistant Staphylococcus aureus (MRSA) strains was studied at the morphological and molecular level. D-SNPs and AgNO3 have the ability to inhibit the growth of the five bacterial strains and resulted in an imbalance in the CAT, GSH, GPx and ATPase levels. MRSA treated with D-SNPs and AgNO3 showed different morphological changes such as apoptotic bodies formation and cell wall damage. Moreover, both caused genotoxicity and denaturation of MRSA cellular proteins. Additionally, TEM micrographs showed the distribution of SNPs synthesized by MRSA. This result shows the ability of MRSA to reduce silver nitrate into silver nanoparticles. These data indicate that D-SNPs may be a significant alternative antibacterial agent against different bacteria, especially MDR bacteria, by targeting the virulence mechanism and biofilm formation, leading to bacterial death.}, } @article {pmid32547965, year = {2020}, author = {Colquhoun, JM and Rather, PN}, title = {Insights Into Mechanisms of Biofilm Formation in Acinetobacter baumannii and Implications for Uropathogenesis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {253}, pmid = {32547965}, issn = {2235-2988}, support = {R21 AI142489/AI/NIAID NIH HHS/United States ; }, mesh = {*Acinetobacter Infections ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Retrospective Studies ; Virulence ; }, abstract = {Multidrug resistant Acinetobacter baumannii is a serious healthcare threat. In fact, the Center for Disease Control recently reported that carbapenem-resistant A. baumannii is responsible for more than 8,500 infections, 700 deaths, and $281 million in healthcare costs annually in the United States with few, if any, treatment options available, leading to its designation as a pathogen of urgent concern and a priority for novel antimicrobial development. It is hypothesized that biofilms are, at least in part, responsible for the high prevalence of A. baumannii nosocomial and recurrent infections because they frequently contaminate hospital surfaces and patient indwelling devices; therefore, there has been a recent push for mechanistic understanding of biofilm formation, maturation and dispersal. However, most research has focused on A. baumannii pneumonia and bloodstream infections, despite a recent retrospective study showing that 17.1% of A. baumannii isolates compiled from clinical studies over the last two decades were obtained from urinary samples. This highlights that A. baumannii is an underappreciated uropathogen. The following minireview will examine our current understanding of A. baumannii biofilm formation and how this influences urinary tract colonization and pathogenesis.}, } @article {pmid32547124, year = {2020}, author = {Khoshnood, S and Savari, M and Abbasi Montazeri, E and Farajzadeh Sheikh, A}, title = {Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {1547-1558}, pmid = {32547124}, issn = {1178-6973}, abstract = {INTRODUCTION: Acinetobacter baumannii is an opportunistic pathogen responsible for nosocomial infections. The emergence of colistin-resistant A. baumannii is a significant threat to public health. The aim of this study was to investigate the molecular characterization and genotyping of clinical A. baumannii isolates in Southwestern Iran.

METHODS: A total of 70 A. baumannii isolates were collected from patients admitted to Imam Khomeini Hospital in Ahvaz, Southwestern Iran. Minimum inhibitory concentration test was conducted by using Vitek 2 system. The presence of biofilm-forming genes and colistin resistance-related genes were evaluated by PCR. The isolates were also examined for their biofilm formation ability and the expression of pmrA and pmrB genes. Finally, multilocus sequence typing (MLST) and PCR-based sequence group were used to determine the genetic relationships of the isolates.

RESULTS: Overall, 61 (87.1%) and 9 (12.8%) isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR), respectively. Colistin and tigecycline with 2 (2.8%) and 32 (45.7%) resistance rates had the highest effect. Among all the isolates, 55 (78.5%), 7 (10%), and 3 (4.3%) were strong, moderate, and weak biofilm producers, respectively. The frequency rates of biofilm-related genes were 64 (91.4%), 70 (100%), 56 (80%), and 22 (31.42%) for bap, ompA, csuE, and blaPER1 , respectively. Overexpression of pmrA and pmrB genes was observed in two colistin-resistance isolates, but the expression of these genes did not change in colistin-sensitive isolates. Additionally, 37 (52.8%) and 8 (11.4%) isolates belonged to groups 1 (ICII) and 2 (IC I), respectively. MLST analysis revealed a total of nine different sequence types that six isolates belonged to clonal complex 92 (corresponding to ST801, ST118, ST138, ST 421, and ST735). Other isolates were belonging to ST133 and ST216, and two colistin-resistant (Ab4 and Ab41) isolates were belonging to ST387 and ST1812.

CONCLUSION: The present study revealed the presence of MDR and XDR A. baumannii isolates harboring biofilm genes and emergence of colistin-resistant isolates in Southwestern Iran. These isolates had high diversity, which was affirmed by typing techniques. The control measures and regular surveillance are urgently needed to preclude the spread of these isolates.}, } @article {pmid32546074, year = {2020}, author = {Thakur, S and Ray, S and Jhunjhunwala, S and Nandi, D}, title = {Insights into coumarin-mediated inhibition of biofilm formation in Salmonella Typhimurium.}, journal = {Biofouling}, volume = {36}, number = {4}, pages = {479-491}, doi = {10.1080/08927014.2020.1773447}, pmid = {32546074}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Coumarins/*pharmacology ; *Salmonella typhimurium ; }, abstract = {Coumarins have been shown to possess antimicrobial, anti-quorum sensing and anti-biofilm properties against a wide range of pathogenic bacteria. This study aimed to shed light on the effects of non-substituted coumarin on biofilm formation by the foodborne pathogen Salmonella Typhimurium. Additionally, its efficacy was tested in combination with another potent anti-biofilm agent, resveratrol. Coumarin inhibited biofilm formation for prolonged periods in millimolar concentrations with marginal effects on planktonic growth. It attenuated curli and cellulose production, likely by downregulating the transcript levels of major biofilm formation genes csgD, csgA and adrA. Coumarin further restricted motility in a dose-dependent manner. In addition, coumarin with resveratrol exhibited improved anti-biofilm properties compared with the individual compounds alone. Thus, coumarin alone or with resveratrol can be employed for inhibiting biofilms in food storage and processing units.}, } @article {pmid32545793, year = {2020}, author = {Doub, JB and Heil, EL and Ntem-Mensah, A and Neeley, R and Ching, PR}, title = {Rifabutin Use in Staphylococcus Biofilm Infections: A Case Series.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {32545793}, issn = {2079-6382}, abstract = {This is a case series of 10 patients who had staphylococcal biofilm infections that were treated with adjuvant rifabutin therapy instead of rifampin therapy. In these cases, rifampin was contraindicated secondary to drug-drug interactions with the patients' chronic medications. Rifabutin therapy was well tolerated with no side effects. As well, no patients had recurrence of their staphylococcal infections. This case series shows that rifabutin can be a beneficial adjuvant therapy in Staphylococcus biofilm infections when drug-drug interactions limit the use of rifampin.}, } @article {pmid32544646, year = {2020}, author = {Aldakheel, FM and Alduraywish, SA and Jhugroo, P and Jhugroo, C and Divakar, DD}, title = {Quantification of pathogenic bacteria in the subgingival oral biofilm samples collected from cigarette-smokers, individuals using electronic nicotine delivery systems and non-smokers with and without periodontitis.}, journal = {Archives of oral biology}, volume = {117}, number = {}, pages = {104793}, doi = {10.1016/j.archoralbio.2020.104793}, pmid = {32544646}, issn = {1879-1506}, mesh = {Aggregatibacter actinomycetemcomitans ; Bacteroides ; *Biofilms ; Chronic Periodontitis/*microbiology ; Electronic Nicotine Delivery Systems ; Humans ; Non-Smokers ; Periodontal Attachment Loss ; Periodontal Pocket ; Porphyromonas gingivalis ; Prevotella intermedia ; Smokers ; Tannerella forsythia ; Treponema denticola ; }, abstract = {OBJECTIVE: The aim of the present study was to quantify pathogenic bacteria isolated from the subgingival oral-biofilm samples collected from cigarette-smokers and ENDS-users with periodontitis, when compared to non-smokers with and without periodontitis.

METHODS: Demographic data was collected using a questionnaire. Periodontal parameters (plaque [PI] and gingival [GI] indices, clinical attachment loss [CAL], probing depth [PD] and marginal bone loss [MBL]) were measured. Subgingival oral bio-film samples were collected and assessed for periodontopathogenic bacteria (Aggregatibacter actinomycetemcomitans [A. actinomycetemcomitans], Prevotella intermedia [P. intermedia], Porphyromonas gingivalis [P. gingivalis], Tannerella forsythia [T. forsythia] and Treponema denticola [T. denticola]). Group-comparisons were performed; and P < 0.01 were considered statistically significant.

RESULTS: All cigarette-smokers, ENDS-users and non-smokers with periodontitis had Grade-B periodontitis. The CFU/mL of A. actinomycetemcomitans (P < 0.001) and P. gingivalis (P < 0.001) were significantly higher among cigarette-smokers (P < 0.01) and ENDS-users (P < 0.01) than non-smokers with periodontitis. The CFU/mL of T. denticola were significantly higher among cigarette-smokers (P < 0.001), ENDS-users (P < 0.001) and non-smokers with periodontitis (P < 0.001) compared with non-smokers without periodontitis. There was no statistically significant difference in the CFU/mL of P. intermedia and T. denticola among cigarette-smokers, ENDS-users and non-smokers with periodontitis.

CONCLUSION: Counts of periodontopathogenic bacteria in the subgingival oral-biofilm are comparable among cigarette-smokers and individuals using ENDS.}, } @article {pmid32543337, year = {2021}, author = {Grygorcewicz, B and Wojciuk, B and Roszak, M and Łubowska, N and Błażejczak, P and Jursa-Kulesza, J and Rakoczy, R and Masiuk, H and Dołęgowska, B}, title = {Environmental Phage-Based Cocktail and Antibiotic Combination Effects on Acinetobacter baumannii Biofilm in a Human Urine Model.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {1}, pages = {25-35}, doi = {10.1089/mdr.2020.0083}, pmid = {32543337}, issn = {1931-8448}, mesh = {Acinetobacter baumannii/*drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Combined Modality Therapy ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Phage Therapy/*methods ; Urine/*microbiology ; }, abstract = {The emergence of multidrug-resistant (MDR) bacterial infections poses a catastrophic threat to medicine. The development of phage-based therapy combined with antibiotics might be an advantageous weapon in the arms race between human and MDR bacteria. A cocktail composed of the MDR Acinetobacter baumannii infecting bacteriophages with high lytic activity was used in combination with antibiotics to destroy a bacterial biofilm in human urine. A. baumannii exhibited varying susceptibility to the host range of bacteriophages used in this study, ranging from 56% to 84%. This study demonstrated that bacteriophages could reduce biofilm biomass in a human urine model, and some of the antibiotics commonly used in the treatment of urinary tract infection (UTI) act synergistically with phage cocktails. Additionally, the combined treatment showed a significantly greater reduction of biofilm biomass and clearance of persister cells.}, } @article {pmid32542998, year = {2021}, author = {Hartman, AM and Jumde, VR and Elgaher, WAM and Te Poele, EM and Dijkhuizen, L and Hirsch, AKH}, title = {Potential Dental Biofilm Inhibitors: Dynamic Combinatorial Chemistry Affords Sugar-Based Molecules that Target Bacterial Glucosyltransferase.}, journal = {ChemMedChem}, volume = {16}, number = {1}, pages = {113-123}, pmid = {32542998}, issn = {1860-7187}, mesh = {Anti-Bacterial Agents/*chemistry/metabolism ; Bacteria/*enzymology ; Bacterial Proteins/*antagonists & inhibitors/metabolism ; Combinatorial Chemistry Techniques ; Drug Discovery ; Glucosyltransferases/*antagonists & inhibitors/metabolism ; Protein Binding ; Small Molecule Libraries/chemistry/metabolism ; Structure-Activity Relationship ; Sugars/*chemistry ; Surface Plasmon Resonance ; }, abstract = {We applied dynamic combinatorial chemistry (DCC) to find novel ligands of the bacterial virulence factor glucosyltransferase (GTF) 180. GTFs are the major producers of extracellular polysaccharides, which are important factors in the initiation and development of cariogenic dental biofilms. Following a structure-based strategy, we designed a series of 36 glucose- and maltose-based acylhydrazones as substrate mimics. Synthesis of the required mono- and disaccharide-based aldehydes set the stage for DCC experiments. Analysis of the dynamic combinatorial libraries (DCLs) by UPLC-MS revealed major amplification of four compounds in the presence of GTF180. Moreover, we found that derivatives of the glucose-acceptor maltose at the C1-hydroxy group act as glucose-donors and are cleaved by GTF180. The synthesized hits display medium to low binding affinity (KD values of 0.4-10.0 mm) according to surface plasmon resonance. In addition, they were investigated for inhibitory activity in GTF-activity assays. The early-stage DCC study reveals that careful design of DCLs opens up easy access to a broad class of novel compounds that can be developed further as potential inhibitors.}, } @article {pmid32542738, year = {2020}, author = {Zhang, C and Zhu, F and Jatt, AN and Liu, H and Niu, L and Zhang, L and Liu, Y}, title = {Characterization of co-culture of Aeromonas and Pseudomonas bacterial biofilm and spoilage potential on refrigerated grass carp (Ctenopharyngodon idellus).}, journal = {Letters in applied microbiology}, volume = {71}, number = {4}, pages = {337-344}, doi = {10.1111/lam.13341}, pmid = {32542738}, issn = {1472-765X}, support = {2018YYSP009//Key Research and Development of Shandong Province, China/ ; 2019GNC106085//Key Research and Development of Shandong Province, China/ ; ZR2018BC060//Shandong Provincial Natural Science Foundation, China/ ; ZR2019PC058//Shandong Provincial Natural Science Foundation, China/ ; }, mesh = {Aeromonas/growth & development/*physiology ; Animals ; Biofilms ; Carps/*microbiology ; Coculture Techniques ; Food Contamination/analysis ; Pseudomonas/growth & development/*physiology ; }, abstract = {Aeromonas and Pseudomonas are important bacterial species involved in spoilage of refrigerated freshwater fish. In this study, 10 Aeromonas and seven Pseudomonas bacterial strains were isolated from spoiled grass carp and identified. Twelve of seventeen bacterial strains showed high potential of biofilm formation and 14 of 17 can produce extracellular protease. In order to explore the spoilage capacity of dual-species, the sterile grass carp fillets were inoculated with mono- and dual-species of Aeromonas salmonicida and Pseudomonas azotoformans strains. The results revealed significantly higher levels of the total viable count and total volatile basic nitrogen in dual-species as compared to mono-species from day 6. The higher contents of histamine, cadaverine and serious degradation in muscles tissue were also observed in dual-species after 10 days of storage. Results of in vitro experiments showed that the co-culture of A. salmonicida and P. azotoformans significantly increased the bacterial maximum growth rate, promoted the biofilm formation and improved the spoilage capacity of bacterial strains. This study has revealed that the co-culture of Aeromonas and Pseudomonas bacterial strains accelerated spoilage process of grass carp and increased biofilm formation. It indicates that the mixed-cultures of spoilage micro-organisms pose a huge threat to food industry.}, } @article {pmid32541123, year = {2020}, author = {Wang, C and Lei, L and Cai, F and Li, Y}, title = {Nitrogen removal and microbial communities of a completely autotrophic nitrogen removal over nitrite (CANON) sequencing batch biofilm reactor (SBBR) at different inorganic carbon (IC) concentrations.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {5}, pages = {1071-1079}, doi = {10.2166/wst.2020.203}, pmid = {32541123}, issn = {0273-1223}, mesh = {Autotrophic Processes ; Biofilms ; Bioreactors ; Carbon ; Denitrification ; *Microbiota ; *Nitrites ; Nitrogen ; }, abstract = {In this study, the completely autotrophic nitrogen removal over nitrite (CANON) process was initiated in a sequencing batch biofilm reactor (SBBR). Then the reactor was operated under different IC/N ratios. The total inorganic nitrogen removal efficiency (TINRE) at IC/N ratios of 0.75, 1.0, 1.25, 1.5 and 2.0 were 37.0 ± 11.0%, 58.9 ± 10.2%, 73.9 ± 3.2%, 73.6 ± 1.8% and 72.6 ± 2.0%, respectively. The suitable range of IC/N ratio in this research is 1.25-2.0. The poor nitrogen removal performance at IC/N ratio of 0.75 was due to the lack of growth substrate for AnAOB and low pH simultaneously; at IC/N ratio of 1.0 this was because the substrate concentration was insufficient for fully recovering the AnAOB activities. Microbial analysis indicated that Nitrosomonas, Nitrospira and Candidatus Brocadia were the main ammonium oxidation bacteria (AOB), nitrite oxidation bacteria (NOB) and anammox bacteria (AnAOB), respectively. In addition, at IC ratios of 1.25 or higher, denitrification was promoted with the rise of IC/N ratio, which might be because the change of IC concentrations caused cell lysis of microorganisms and provided organic matter for denitrification.}, } @article {pmid32541108, year = {2020}, author = {Skoyles, A and Chaganti, SR and Mundle, SOC and Weisener, CG}, title = {'Nitrification kinetics and microbial community dynamics of attached biofilm in wastewater treatment'.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {5}, pages = {891-905}, doi = {10.2166/wst.2020.170}, pmid = {32541108}, issn = {0273-1223}, mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; Kinetics ; *Microbiota ; *Nitrification ; Nitrogen ; RNA, Ribosomal, 16S ; Wastewater ; }, abstract = {A comparative bench-scale and field site analysis of BioCord was conducted to investigate seasonal microbial community dynamics and its impact on nitrogen removal in wastewater. This was assessed using metabolite (NO3 [-]) stable isotope analysis, high-throughput sequencing of the 16S rRNA gene, and RT-qPCR of key genes in biological treatment representing nitrification, anammox, and denitrification. Bench-scale experiments showed an increase in nitrifiers with increasing ammonia loading resulting in an ammonia removal efficiency up to 98 ± 0.14%. Stable isotope analysis showed that [15]ɛ and δ[18]ONO3 could be used in monitoring the efficiency of the enhanced biological nitrification. In the lagoon field trials, an increase in total nitrogen promoted three principle nitrifying genera (Nitrosomonas, Nitrospira, Candidatus Nitrotoga) and enhanced the expression of denitrification genes (nirK, norB, and nosZ). Further, anaerobic ammonia oxidizers were active within BioCord biofilm. Even at lower temperatures (2-6°C) the nitrifying bacteria remained active on the BioCord.}, } @article {pmid32540933, year = {2020}, author = {Parthasarathy, S and Jordan, LD and Schwarting, N and Woods, MA and Abdullahi, Z and Varahan, S and Passos, PMS and Miller, B and Hancock, LE}, title = {Involvement of Chromosomally Encoded Homologs of the RRNPP Protein Family in Enterococcus faecalis Biofilm Formation and Urinary Tract Infection Pathogenesis.}, journal = {Journal of bacteriology}, volume = {202}, number = {17}, pages = {}, pmid = {32540933}, issn = {1098-5530}, support = {K12 GM063651/GM/NIGMS NIH HHS/United States ; R01 AI077782/AI/NIAID NIH HHS/United States ; R21 AI117424/AI/NIAID NIH HHS/United States ; R25 GM060182/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial ; Enterococcus faecalis/drug effects/genetics/*metabolism ; Gene Expression Regulation, Bacterial/physiology ; Humans ; Urinary Tract Infections/*microbiology ; }, abstract = {Enterococcus faecalis is an opportunistic pathogen capable of causing infections, including endocarditis and urinary tract infections (UTI). One of the well-characterized quorum-sensing pathways in E. faecalis involves coordination of the conjugal transfer of pheromone-responsive plasmids by PrgX, a member of the RRNPP protein family. Members of this protein family in various Firmicutes have also been shown to contribute to numerous cellular processes, including sporulation, competence, conjugation, nutrient sensing, biofilm formation, and virulence. As PrgX is a plasmid-encoded RRNPP family member, we surveyed the genome of the multidrug-resistant strain V583 for additional RRNPP homologs using computational searches and refined those identified hits for predicted structural similarities to known RRNPP family members. This led us to investigate the contribution of the chromosomally encoded RRNPP homologs to biofilm processes and pathogenesis in a catheter-associated urinary tract infection (CAUTI) model. In this study, we identified five such homologs and report that 3 of the 5 homologs, EF0073, EF1599, and EF1316, affect biofilm formation as well as outcomes in the CAUTI model.IMPORTANCEEnterococcus faecalis causes health care-associated infections and displays resistance to a variety of broad-spectrum antibiotics by acquisition of resistance traits as well as the ability to form biofilms. Even though a growing number of factors related to biofilm formation have been identified, mechanisms that contribute to biofilm formation are still largely unknown. Members of the RRNPP protein family regulate a diverse set of biological reactions in low-G+C Gram-positive bacteria (Firmicutes). Here, we identify three predicted structural homologs of the RRNPP family, EF0073, EF1599, and EF1316, which affect biofilm formation and CAUTI pathogenesis.}, } @article {pmid32540665, year = {2020}, author = {Yuan, S and Yu, Z and Pan, S and Huang, J and Meng, F}, title = {Deciphering the succession dynamics of dominant and rare genera in biofilm development process.}, journal = {The Science of the total environment}, volume = {739}, number = {}, pages = {139961}, doi = {10.1016/j.scitotenv.2020.139961}, pmid = {32540665}, issn = {1879-1026}, mesh = {*Bacteria ; Biofilms ; *Ecosystem ; In Situ Hybridization, Fluorescence ; }, abstract = {Deciphering the succession dynamics of dominant and rare taxa is crucial to understand the stability and ecosystem functions of biofilm communities. However, the essential laws of the succession dynamics based on dominant and rare taxa were still unenlightened. Herein, we investigated the succession dynamics of dominant and rare genera in multi-species biofilms developed in flow cells fed with 10 and 40 mg-TOC/L LB broth. The relative abundance of dominant genera (Enterobacteria and Acinetobacter) decreased remarkably (from 94.63% to 73.22%) in 10 mg-TOC/L LB broth, whereas they kept relatively steady (93.75 ± 4.23%) along with the cultivation time in 40 mg-TOC/L LB broth. Fluorescence in situ hybridization showed that rare genera tended to form clusters at both concentrations, while weaker dispersal of dominant genera caused patchier biofilm structures in 10 mg-TOC/L LB broth compared to that in 40 mg-TOC/L LB broth. Null model analyses further demonstrated that the stochastic ecological drift was more pronounced in the community assembly of biofilms in 10 mg-TOC/L LB broth (73.33%) than those in 40 mg-TOC/L LB broth (60.95%), weakening the competitive superiority of dominant taxa in the patchier biofilms. In addition, the co-occurrence network reflected that the positive interactions among rare genera contributed to exclude dominant genera in 10 mg-TOC/L LB broth, whereas negative interactions only occurred between the dominant Enterobacter and Acinetobacter or rare Comamonas in 40 mg-TOC/L LB broth. This study highlighted the distinctive succession dynamics of dominant and rare genera in biofilms at different substrate concentrations, which would advance our understanding of the biofilm communities in biofilm-related process.}, } @article {pmid32539963, year = {2020}, author = {Wu, S and Huang, J and Zhang, F and Dai, J and Pang, R and Zhang, J and Zeng, H and Gu, Q and Zhang, S and Zhang, Y and Xue, L and Wang, J and Ding, Y and Wu, Q}, title = {Staphylococcus argenteus isolated from retail foods in China: Incidence, antibiotic resistance, biofilm formation and toxin gene profile.}, journal = {Food microbiology}, volume = {91}, number = {}, pages = {103531}, doi = {10.1016/j.fm.2020.103531}, pmid = {32539963}, issn = {1095-9998}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; China/epidemiology ; *Drug Resistance, Bacterial/genetics ; Enterotoxins/*genetics ; *Food Microbiology ; Genes, Bacterial ; Genotype ; Incidence ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Prevalence ; Staphylococcus/drug effects/genetics/*isolation & purification/pathogenicity ; Virulence/genetics ; }, abstract = {Staphylococcus argenteus is a novel species of coagulase-positive staphylococci which was separated from Staphylococcus aureus in 2014. It can threaten human health like S. aureus but can not identify with conventional biochemical or other phenotypic testing. From 2011 to 2016, 1581 S. aureus strains were isolated from 4300 samples from retail foods covering most provincial capitals in China. According to multilocus sequence typing (MLST) and PCR confirmation, 7.2% of isolates (114/1581) were confirmed as S. argenteus. The pathogen was distributed in 22 of 39 sampled cities and all food types. Interestingly, most S. argenteus positive samples were collected from coastal cities in South China. MLST detected 8 different sequence types (STs), including five new STs. CC2250 was the predominant lineage of S. argenteus, followed by CC1223. To further characterize the isolates, their antibiotic resistance, virulence genes, biofilm formation and biofilm-related genes were examined. The pvl gene was not detected in S. argenteus, and only 1 isolate (0.9%) was positive for the tsst-1 gene. For 18 enterotoxin genes, 16.7% (19/114) of isolates harboured more than three genes, whereas 70.2% (80/114) of isolates had none of the investigated genes. Penicillin and ampicillin were the major antibiotics to which the S. argenteus isolates were resistant, followed by tetracycline, kanamycin and fusidic acid. A total of 94.7% of isolates had the ability to produce biofilms and all isolates harboured icaA, fnbA, and fib genes. Other biofilm-related genes, such as eno, clfB, fnbB, and icaC, were also found in 99.1%, 92.1%, 88.6%, and 74.6% of isolates, respectively. This study is the first systematic investigation of the prevalence of S. argenteus in retail foods in China and shows their ubiquity in food. We also provide comprehensive surveillance of the incidence of S. argenteus in retail foods and information to enable more accurate and effective treatment of infections of this new species.}, } @article {pmid32538610, year = {2020}, author = {Martínez, SR and Ibarra, LE and Ponzio, RA and Forcone, MV and Wendel, AB and Chesta, CA and Spesia, MB and Palacios, RE}, title = {Photodynamic Inactivation of ESKAPE Group Bacterial Pathogens in Planktonic and Biofilm Cultures Using Metallated Porphyrin-Doped Conjugated Polymer Nanoparticles.}, journal = {ACS infectious diseases}, volume = {6}, number = {8}, pages = {2202-2213}, doi = {10.1021/acsinfecdis.0c00268}, pmid = {32538610}, issn = {2373-8227}, mesh = {Bacteria ; Biofilms ; *Nanoparticles ; Plankton ; Polymers ; *Porphyrins/pharmacology ; Staphylococcus aureus ; }, abstract = {Photodynamic inactivation (PDI) protocols using photoactive metallated porphyrin-doped conjugated polymer nanoparticles (CPNs) and blue light were developed to eliminate multidrug-resistant pathogens. CPNs-PDI protocols using varying particle concentrations and irradiation doses were tested against nine pathogenic bacterial strains including antibiotic-resistant bacteria of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens group. The bactericidal effect was achieved in methicillin-resistant Staphylococus aureus (S. aureus) strains using low light doses (9.6-14.4 J/cm[2]), while Gram-negative bacteria required a higher light dose (28.8 J/cm[2]). The bacteria-CPN interaction was studied through flow cytometry, taking advantage of the intrinsic CPN fluorescence, demonstrating that CPNs efficiently bind to the bacterial envelope. Finally, the performance of CPNs-PDI was explored in biofilms; good antibiofilm ability and almost complete eradication were observed for S. aureus and Escherichia coli biofilms, respectively, using confocal microscopy. Overall, we demonstrated that CPNs-PDI is an efficient tool not only to kill superbugs as sessile cells but also to disrupt and eradicate biofilms of highly relevant pathogenic bacterial species.}, } @article {pmid32528653, year = {2019}, author = {Septiana, S and Bachtiar, BM and Yuliana, ND and Wijaya, CH}, title = {Cajuputs candy impairs Candida albicans and Streptococcus mutans mixed biofilm formation in vitro.}, journal = {F1000Research}, volume = {8}, number = {}, pages = {1923}, pmid = {32528653}, issn = {2046-1402}, mesh = {Biofilms ; Candida albicans ; Candy ; Indonesia ; *Melaleuca ; *Streptococcus mutans ; }, abstract = {Background:Cajuputs candy (CC), an Indonesian functional food, utilizes the bioactivity of Melaleuca cajuputi essential oil (MCEO) to maintain oral cavity health. Synergistic interaction between Candida albicans and Streptococcus mutans is a crucial step in the pathogenesis of early childhood caries. Our recent study revealed several alternative MCEOs as the main flavors in CC. The capacity of CC to interfere with the fungus-bacterium relationship remains unknown. This study aimed to evaluate CC efficacy to impair biofilm formation by these dual cariogenic microbes. Methods: The inhibition capacity of CC against mixed-biofilm comprising C. albicans and S. mutans was assessed by quantitative (crystal violet assay, tetrazolium salt [MTT] assay, colony forming unit/mL counting, biofilm-related gene expression) and qualitative analysis (light microscopy and scanning electron microscopy). Result: Both biofilm-biomass and viable cells were significantly reduced in the presence of CC. Scanning electron microscopy imaging confirmed this inhibition capacity, demonstrating morphology alteration of C. albicans, along with reduced microcolonies of S. mutans in the biofilm mass. This finding was related to the transcription level of selected biofilm-associated genes, expressed either by C. albicans or S. mutans. Based on qPCR results, CC could interfere with the transition of C. albicans yeast form to the hyphal form, while it suppressed insoluble glucan production by S. mutans. G2 derived from Mojokerto MCEO showed the greatest inhibition activity on the relationship between these cross-kingdom oral microorganisms (p < 0.05). Conclusion: In general, all CC formulas showed biofilm inhibition capacity. Candy derived from Mojokerto MCEO showed the greatest capacity to maintain the yeast form of C. albicans and to inhibit extracellular polysaccharide production by S. mutans. Therefore, the development of dual-species biofilms can be impaired effectively by the CC tested.}, } @article {pmid32535996, year = {2021}, author = {Galego, L and Barahona, S and Romão, CV and Arraiano, CM}, title = {Phosphorylation status of BolA affects its role in transcription and biofilm development.}, journal = {The FEBS journal}, volume = {288}, number = {3}, pages = {961-979}, doi = {10.1111/febs.15447}, pmid = {32535996}, issn = {1742-4658}, mesh = {Amino Acid Sequence ; Binding Sites/genetics ; Biofilms/*growth & development ; Blotting, Western ; Escherichia coli/*genetics/metabolism/physiology ; Escherichia coli Proteins/chemistry/*genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Mass Spectrometry/methods ; Mutation ; Phosphorylation ; Protein Domains ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Homology, Amino Acid ; Serine/chemistry/genetics/metabolism ; Threonine/chemistry/genetics/metabolism ; Transcription Factors/chemistry/*genetics/metabolism ; }, abstract = {BolA has been characterized as an important transcriptional regulator, which is induced in stationary phase of growth, and in response to several stresses. In Escherichia coli, its cellular function is associated with cell wall synthesis and division, morphology, permeability, motility and biofilm formation. Phosphorylation has been widely described as one of the most important events involved in the modulation of the activity of many transcription factors. In the present work, we have demonstrated in vivo and by mass spectrometry that BolA is phosphorylated in four highly conserved protein positions: S26, S45, T81 and S95. S95 is located in the C terminus unstructured region of the protein, and the other three sites are in the DNA-binding domain. These positions were mutated to nonphosphorylated residues, and their effects were investigated on different known BolA functions. Using northern blot experiments, we showed that the regulation of the expression of these Ser/Thr BolA mutants is performed at the post-translational level. Western blot results revealed that the stability/turnover of the mutated BolA proteins is differently affected depending on the dephosphorylated residue. Moreover, we provide evidences that phosphorylation events are crucial in the modulation of BolA activity as a transcription factor and as a regulator of cell morphology and biofilm development. Here, we propose that phosphorylation affects BolA downstream functions and discuss the possible significance of these phosphoresidues in the protein structure, stability, dimerization and function as a transcription factor.}, } @article {pmid32534180, year = {2020}, author = {Ouyang, J and Feng, W and Lai, X and Chen, Y and Zhang, X and Rong, L and Sun, F and Chen, Y}, title = {Quercetin inhibits Pseudomonas aeruginosa biofilm formation via the vfr-mediated lasIR system.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104291}, doi = {10.1016/j.micpath.2020.104291}, pmid = {32534180}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics ; Biofilms ; Gene Expression Regulation, Bacterial ; *Pseudomonas aeruginosa/genetics ; Pyocyanine ; *Quercetin/pharmacology ; Quorum Sensing ; Virulence Factors/genetics ; }, abstract = {Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause biofilm-associated infections. Biofilm formation is partially regulated by the quorum sensing (QS) system, and quercetin can inhibit QS, biofilm formation and virulence factors. We therefore speculated that quercetin would inhibit the formation of P. aeruginosa biofilm via the QS system. In this study, we successfully constructed lasI, rhlI and lasI/rhlI gene-knockout strains. The knockout of the lasI and lasI/rhlI genes resulted in decreases in adhesion, biofilm formation, swarming motility and the expression of biofilm-associated genes, whereas deletion of the rhlI gene had no obvious influence on these biofilm-related indicators with the exception of the swarming motility. After treatment with quercetin, the lasI- and lasI/rhlI-mutant strains exhibited increased adhesion, biofilm formation, swarming motility and biofilm-associated gene expression compared with the control group. However, quercetin still exerted an inhibitory effect on these physiological factors and the biofilm-associated gene expression in the rhlI-mutant strain. The knockout of QS genes reduced the production of pyocyanin and protease activity, but after the virulence factors of the QS-mutant strains treated with quercetin showed almost no differences compared with those of the control group. In addition, quercetin could significantly inhibit vfr gene expression regardless of the presence of QS genes. The results indicated that quercetin might inhibit the lasIR system through the vfr gene and ultimately the formation of P. aeruginosa biofilms.}, } @article {pmid32534064, year = {2020}, author = {Richter, AM and Possling, A and Malysheva, N and Yousef, KP and Herbst, S and von Kleist, M and Hengge, R}, title = {Local c-di-GMP Signaling in the Control of Synthesis of the E. coli Biofilm Exopolysaccharide pEtN-Cellulose.}, journal = {Journal of molecular biology}, volume = {432}, number = {16}, pages = {4576-4595}, pmid = {32534064}, issn = {1089-8638}, mesh = {Biofilms/*growth & development ; Cellulose/metabolism ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli K12/metabolism/*physiology ; Escherichia coli Proteins/*metabolism ; Glucosyltransferases/metabolism ; Intracellular Signaling Peptides and Proteins/metabolism ; Phosphoric Diester Hydrolases/metabolism ; Phosphorus-Oxygen Lyases/metabolism ; Polysaccharides, Bacterial/*metabolism ; Signal Transduction ; }, abstract = {In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.}, } @article {pmid32533131, year = {2020}, author = {Rumbaugh, KP and Sauer, K}, title = {Biofilm dispersion.}, journal = {Nature reviews. Microbiology}, volume = {18}, number = {10}, pages = {571-586}, pmid = {32533131}, issn = {1740-1534}, support = {R01 AI075257/AI/NIAID NIH HHS/United States ; R01 AI080710/AI/NIAID NIH HHS/United States ; R01 AI150761/AI/NIAID NIH HHS/United States ; R21 AI137462/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacteria/*genetics/growth & development/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Endonucleases/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Glycoside Hydrolases/genetics/metabolism ; Mice ; Peptide Hydrolases/genetics/metabolism ; Phosphoric Diester Hydrolases/genetics/metabolism ; Plankton/genetics/growth & development/metabolism ; Quorum Sensing/*genetics ; Signal Transduction ; Transcriptome ; }, abstract = {The formation of microbial biofilms enables single planktonic cells to assume a multicellular mode of growth. During dispersion, the final step of the biofilm life cycle, single cells egress from the biofilm to resume a planktonic lifestyle. As the planktonic state is considered to be more vulnerable to antimicrobial agents and immune responses, dispersion is being considered a promising avenue for biofilm control. In this Review, we discuss conditions that lead to dispersion and the mechanisms by which native and environmental cues contribute to dispersion. We also explore recent findings on the role of matrix degradation in the dispersion process, and the distinct phenotype of dispersed cells. Last, we discuss the translational and therapeutic potential of dispersing bacteria during infection.}, } @article {pmid32532998, year = {2020}, author = {Thibeaux, R and Soupé-Gilbert, ME and Kainiu, M and Girault, D and Bierque, E and Fernandes, J and Bähre, H and Douyère, A and Eskenazi, N and Vinh, J and Picardeau, M and Goarant, C}, title = {The zoonotic pathogen Leptospira interrogans mitigates environmental stress through cyclic-di-GMP-controlled biofilm production.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {24}, pmid = {32532998}, issn = {2055-5008}, mesh = {Animals ; Bacterial Proteins/genetics ; Bacterial Zoonoses/microbiology ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/*genetics ; Gene Expression Regulation, Bacterial ; Humans ; Leptospira interrogans/*physiology ; Mutation ; Phosphoric Diester Hydrolases/*genetics ; Phosphorus-Oxygen Lyases/*genetics ; Spatio-Temporal Analysis ; Stress, Physiological ; }, abstract = {The zoonotic bacterium Leptospira interrogans is the aetiological agent of leptospirosis, a re-emerging infectious disease that is a growing public health concern. Most human cases of leptospirosis result from environmental infection. Biofilm formation and its contribution to the persistence of virulent leptospires in the environment or in the host have scarcely been addressed. Here, we examined spatial and time-domain changes in biofilm production by L. interrogans. Our observations showed that biofilm formation in L. interrogans is a highly dynamic process and leads to a polarized architecture. We notably found that the biofilm matrix is composed of extracellular DNA, which enhances the biofilm's cohesiveness. By studying L. interrogans mutants with defective diguanylate cyclase and phosphodiesterase genes, we show that biofilm production is regulated by intracellular levels of bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) and underpins the bacterium's ability to withstand a wide variety of simulated environmental stresses. Our present results show how the c-di-GMP pathway regulates biofilm formation by L. interrogans, provide insights into the environmental persistence of L. interrogans and, more generally, highlight leptospirosis as an environment-borne threat to human health.}, } @article {pmid32530919, year = {2020}, author = {Harrison, JJ and Almblad, H and Irie, Y and Wolter, DJ and Eggleston, HC and Randall, TE and Kitzman, JO and Stackhouse, B and Emerson, JC and Mcnamara, S and Larsen, TJ and Shendure, J and Hoffman, LR and Wozniak, DJ and Parsek, MR}, title = {Elevated exopolysaccharide levels in Pseudomonas aeruginosa flagellar mutants have implications for biofilm growth and chronic infections.}, journal = {PLoS genetics}, volume = {16}, number = {6}, pages = {e1008848}, pmid = {32530919}, issn = {1553-7404}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; //CIHR/Canada ; R01 AI061396/AI/NIAID NIH HHS/United States ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/growth & development ; Biosynthetic Pathways/genetics ; Cystic Fibrosis/complications/microbiology ; Flagella/metabolism ; *Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions/*genetics ; Humans ; Mutagenesis, Site-Directed ; Mutation ; Polysaccharides, Bacterial/biosynthesis ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*genetics/pathogenicity ; Selection, Genetic ; }, abstract = {Pseudomonas aeruginosa colonizes the airways of cystic fibrosis (CF) patients, causing infections that can last for decades. During the course of these infections, P. aeruginosa undergoes a number of genetic adaptations. One such adaptation is the loss of swimming motility functions. Another involves the formation of the rugose small colony variant (RSCV) phenotype, which is characterized by overproduction of the exopolysaccharides Pel and Psl. Here, we provide evidence that the two adaptations are linked. Using random transposon mutagenesis, we discovered that flagellar mutations are linked to the RSCV phenotype. We found that flagellar mutants overexpressed Pel and Psl in a surface-contact dependent manner. Genetic analyses revealed that flagellar mutants were selected for at high frequencies in biofilms, and that Pel and Psl expression provided the primary fitness benefit in this environment. Suppressor mutagenesis of flagellar RSCVs indicated that Psl overexpression required the mot genes, suggesting that the flagellum stator proteins function in a surface-dependent regulatory pathway for exopolysaccharide biosynthesis. Finally, we identified flagellar mutant RSCVs among CF isolates. The CF environment has long been known to select for flagellar mutants, with the classic interpretation being that the fitness benefit gained relates to an impairment of the host immune system to target a bacterium lacking a flagellum. Our new findings lead us to propose that exopolysaccharide production is a key gain-of-function phenotype that offers a new way to interpret the fitness benefits of these mutations.}, } @article {pmid32529892, year = {2020}, author = {Muzammil, S and Khurshid, M and Nawaz, I and Siddique, MH and Zubair, M and Nisar, MA and Imran, M and Hayat, S}, title = {Aluminium oxide nanoparticles inhibit EPS production, adhesion and biofilm formation by multidrug resistant Acinetobacter baumannii.}, journal = {Biofouling}, volume = {36}, number = {4}, pages = {492-504}, doi = {10.1080/08927014.2020.1776856}, pmid = {32529892}, issn = {1029-2454}, mesh = {*Acinetobacter baumannii ; Aluminum Oxide/*toxicity ; Anti-Bacterial Agents ; Biofilms/*drug effects/growth & development ; Extracellular Polymeric Substance Matrix/*metabolism ; HeLa Cells ; Humans ; Microbial Sensitivity Tests ; Nanoparticles/*toxicity ; }, abstract = {Acinetobacter baumannii is a biofilm forming multidrug resistant (MDR) pathogen responsible for respiratory tract infections. In this study, aluminium oxide nanoparticles (Al2O3 NPs) were synthesized and characterized by TEM and EDX and shown to be spherical shaped nanoparticles with a diameter < 10 nm. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) for the Al2O3 NPs ranged between 125 and 1,000 µg ml[-1]. Exposure to NPs caused cellular membrane disruption, indicated by an increase in cellular leakage of the contents. Biofilm inhibition was 11.64 to 70.2%, whereas attachment of bacteria to polystyrene surfaces was reduced to 48.8 to 51.9% in the presence of NPs. Nanoparticles also reduced extracellular polymeric substance production and the biomass of established biofilms. The data revealed the non-toxic nature of Al2O3 NPs up to a concentrations of 120 µg ml[-1] in HeLa cell lines. These results demonstrate an effective and safer use of Al2O3 NPs against the MDR A. baumannii by targeting biofilm formation, adhesion and EPS production.}, } @article {pmid32529277, year = {2020}, author = {Eran, Z and Akçelik, M and Yazıcı, BC and Özcengiz, G and Akçelik, N}, title = {Regulation of biofilm formation by marT in Salmonella Typhimurium.}, journal = {Molecular biology reports}, volume = {47}, number = {7}, pages = {5041-5050}, doi = {10.1007/s11033-020-05573-6}, pmid = {32529277}, issn = {1573-4978}, support = {114Z871//TUBITAK/ ; }, mesh = {Bacterial Adhesion ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Caco-2 Cells ; *Gene Expression Regulation, Bacterial ; Hep G2 Cells ; Humans ; Mutation ; Promoter Regions, Genetic ; Salmonella typhimurium/*genetics/pathogenicity/physiology ; }, abstract = {In this study, we aimed at identifying the regulatory role of marT gene, known as the regulator of misL, on 15 different biofilm-related genes in S. Typhimurium 14028 strain. We also tested the strains for their ability to form biofilm and determined the adherence characteristics of the wild type and the mutant strains of the organism on Caco-2 and HEp-2 cells. For comparative analyses of the candidate genes, individual gene mutations were created via antibiotic gene cassette insertion into each gene of interest. marT gene was cloned behind an arabinose inducible BAD promoter in order to control marT expression. This recombinant plasmid was transfer into each of the 15 mutant strains to investigate the level of expression of each single gene in the presence and absence of marT induction. Besides determination of variations in biofilm formation by each mutant strain, the attachment characteristics of them onto Caco-2 and HEp-2 cell lines were also reported. As a result of attachments experiments on polystyrene surfaces, it was determined that the biofilm production capacity of each mutant strain decreased in a statistically significant manner (p < 0.05). QRT-PCR trials indicated that the marT gene regulates the expression of 14 genes, namely fimA, fimD, fimF, fimH, stjB, stjC, csgA, csgD, ompC, sthB, sthE, rmbA, fliZ and yaiC, in a positive manner. QRT-PCR studies were also revealed that the MarT protein positively regulates its own promoter. When the adherence characteristics of the mutant strains and the wild-type were investigated by using Caco-2 and HEp-2 cells, it was determined that the single gene mutations did have no effect on bacterial adhesion. In view of our mutational analyses and biofilm formation studies, it was concluded that fliZ, ompC, rmbA, stjB and stjC genes are related with biofilm formation in Salmonella, besides other cellular functions of them. Taken together, our data suggested that the regulatory role of MarT protein is not only restricted to the regulation of misL gene expression, but it rather acts as a general regulator on the biofilm-related genes in Salmonella.}, } @article {pmid32528421, year = {2020}, author = {Liu, C and Sun, D and Zhu, J and Liu, J and Liu, W}, title = {The Regulation of Bacterial Biofilm Formation by cAMP-CRP: A Mini-Review.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {802}, pmid = {32528421}, issn = {1664-302X}, abstract = {Biofilms are communities of microorganisms that live in a self-produced extracellular matrix in order to survive in hostile environments. Second messengers, such as c-di-GMP and cAMP, participate in the regulation of biofilm formation. c-di-GMP is a major molecule that is involved in modulating the bacterial transition between a planktonic lifestyle and biofilm formation. Aside from regulating carbon catabolism repression in most bacteria, cAMP has also been found to mediate biofilm formation in many bacteria. Although the underlying mechanisms of biofilm formation mediated by cAMP-CRP have been well-investigated in several bacteria, the regulatory pathways of cAMP-CRP are still poorly understood compared to those of c-di-GMP. Moreover, some bacteria appear to form biofilm in response to changes in carbon source type or concentration. However, the relationship between the carbon metabolisms and biofilm formation remains unclear. This mini-review provides an overview of the cAMP-CRP-regulated pathways involved in biofilm formation in some bacteria. This information will benefit future investigations of the underlying mechanisms that connect between biofilm formation with nutrient metabolism, as well as the cross-regulation between multiple second messengers.}, } @article {pmid32527216, year = {2020}, author = {Bhardwaj, RG and Ellepolla, A and Drobiova, H and Karched, M}, title = {Biofilm growth and IL-8 & TNF-α-inducing properties of Candida albicans in the presence of oral gram-positive and gram-negative bacteria.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {156}, pmid = {32527216}, issn = {1471-2180}, support = {SRUL 01/14//Kuwait University/International ; }, mesh = {Biofilms/*growth & development ; Blood/immunology/microbiology ; Candida albicans/immunology/*physiology ; Gram-Negative Bacteria/*physiology ; Gram-Positive Bacteria/*physiology ; Humans ; Interleukin-8/*genetics/metabolism ; Microbial Interactions ; Mouth/microbiology ; Tumor Necrosis Factor-alpha/*genetics/metabolism ; Up-Regulation ; }, abstract = {BACKGROUND: Interaction of C. albicans with oral bacteria is crucial for its persistence, but also plays a potential role in the infection process. In the oral cavity, it grows as part of dental plaque biofilms. Even though growth and interaction of C. albicans with certain bacterial species has been studied, little is known about its biofilm growth in vitro in the simultaneous presence of Gram-negative and Gram-positive bacteria. The aim was to evaluate the growth of C. albicans in polymicrobial biofilms comprising oral Gram-negative and Gram-positive bacteria. Further, we also aimed to assess the potential of C. albicans in the Candida-bacteria polymicrobial biofilm to elicit cytokine gene expression and cytokine production from human blood cells.

RESULTS: C. albicans cell counts increased significantly up to 48 h in polymicrobial biofilms (p < 0.05), while the bacterial counts in the same biofilms increased only marginally as revealed by qPCR absolute quantification. However, the presence of bacteria in the biofilm did not seem to affect the growth of C. albicans. Expression of IL-8 gene was significantly (p < 0.05) higher upon stimulation from biofilm-supernatants than from biofilms in polymicrobial setting. On the contrary, TNF-α expression was significantly higher in biofilms than in supernatants but was very low (1-4 folds) in the monospecies biofilm of C. albicans. ELISA cytokine quantification data was in agreement with mRNA expression results.

CONCLUSION: Persistence and enhanced growth of C. albicans in polymicrobial biofilms may imply that previously reported antagonistic effect of A. actinomycetemcomitans was negated. Increased cytokine gene expression and cytokine production induced by Candida-bacteria polymicrobial biofilms and biofilm supernatants suggest that together they possibly exert an enhanced stimulatory effect on IL-8 and TNF-α production from the host.}, } @article {pmid32526346, year = {2020}, author = {Bhadila, G and Wang, X and Zhou, W and Menon, D and Melo, MAS and Montaner, S and Oates, TW and Weir, MD and Sun, J and Xu, HHK}, title = {Novel low-shrinkage-stress nanocomposite with remineralization and antibacterial abilities to protect marginal enamel under biofilm.}, journal = {Journal of dentistry}, volume = {99}, number = {}, pages = {103406}, doi = {10.1016/j.jdent.2020.103406}, pmid = {32526346}, issn = {1879-176X}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Calcium Phosphates/pharmacology ; Composite Resins/pharmacology ; Dental Enamel ; Methacrylates/pharmacology ; *Nanocomposites ; Streptococcus mutans ; }, abstract = {OBJECTIVES: Polymerization shrinkage stress may lead to marginal damage, microleakage and failure of composite restorations. The objectives of this study were to : (1) develop a novel nanocomposite with low-shrinkage-stress, antibacterial and remineralization properties to reduce marginal enamel demineralization under biofilms; (2) evaluate the mechanical properties of the composite and calcium (Ca) and phosphate (P) ion release; and (3) investigate the cytotoxicity of the new low-shrinkage-stress monomer in vitro.

METHODS: The low-shrinkage-stress resin consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE), and 3 % dimethylaminohexadecyl methacrylate (DMAHDM) and 20 % calcium phosphate nanoparticles (NACP) were added. Mechanical properties, polymerization shrinkage stress, and degree of conversion were evaluated. The growth of Streptococcus mutans (S. mutans) on enamel slabs with different composites was assessed. Ca and P ion releases and monomer cytotoxicity were measured.

RESULTS: Composite with DMAHDM and NACP had flexural strength of 84.9 ± 10.3 MPa (n = 6), matching that of a commercial control composite. Adding 3 % DMAHDM did not negatively affect the composite ion release. Under S. mutans biofilm, the marginal enamel hardness was 1.2 ± 0.1 GPa for the remineralizing and antibacterial group, more than 2-fold the 0.5 ± 0.07 GPa for control (p < 0.05). The polymerization shrinkage stress of the new composite was 40 % lower than that of traditional composite control (p < 0.05). The new monomers had fibroblast viability similar to that of traditional monomer control (p > 0.1).

CONCLUSION: A novel low-shrinkage-stress nanocomposite was developed with remineralizing and antibacterial properties. This new composite is promising to inhibit recurrent caries at the restoration margins by reducing polymerization stress and protecting enamel hardness.}, } @article {pmid32523805, year = {2020}, author = {Lin, MF and Lin, YY and Lan, CY}, title = {Characterization of biofilm production in different strains of Acinetobacter baumannii and the effects of chemical compounds on biofilm formation.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e9020}, pmid = {32523805}, issn = {2167-8359}, abstract = {Acinetobacter baumannii, an important emerging pathogen of nosocomial infections, is known for its ability to form biofilms. Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, which increases the probability of nosocomial infections and outbreaks. This study was undertaken to characterize the biofilm production of different strains of A. baumannii and the effects of chemical compounds, especially antibiotics, on biofilm formation. In this study, no statistically significant relationship was observed between the ability to form a biofilm and the antimicrobial susceptibility of the A. baumannii clinical isolates. Biofilm formation caused by A. baumannii ATCC 17978 after gene knockout of two-component regulatory system gene baeR, efflux pump genes emrA/emrB and outer membrane coding gene ompA revealed that all mutant strains had less biofilm formation than the wild-type strain, which was further supported by the images from scanning electron microscopy and confocal laser scanning microscopy. The addition of amikacin, colistin, LL-37 or tannic acid decreased the biofilm formation ability of A. baumannii. In contrast, the addition of lower subinhibitory concentration tigecycline increased the biofilm formation ability of A. baumannii. Minimum biofilm eradication concentrations of amikacin, imipenem, colistin, and tigecycline were increased obviously for both wild type and multidrug resistant clinical strain A. baumannii VGH2. In conclusion, the biofilm formation ability of A. baumannii varied in different strains, involved many genes and could be influenced by many chemical compounds.}, } @article {pmid32523574, year = {2020}, author = {Lohse, MB and Gulati, M and Craik, CS and Johnson, AD and Nobile, CJ}, title = {Combination of Antifungal Drugs and Protease Inhibitors Prevent Candida albicans Biofilm Formation and Disrupt Mature Biofilms.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {1027}, pmid = {32523574}, issn = {1664-302X}, support = {R35 GM124594/GM/NIGMS NIH HHS/United States ; R41 AI112038/AI/NIAID NIH HHS/United States ; R01 AI083311/AI/NIAID NIH HHS/United States ; R43 AI131710/AI/NIAID NIH HHS/United States ; P50 AI150476/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilms formed by the fungal pathogen Candida albicans are resistant to many of the antifungal agents commonly used in the clinic. Previous reports suggest that protease inhibitors, specifically inhibitors of aspartyl proteases, could be effective antibiofilm agents. We screened three protease inhibitor libraries, containing a total of 80 compounds for the abilities to prevent C. albicans biofilm formation and to disrupt mature biofilms. The compounds were screened individually and in the presence of subinhibitory concentrations of the most commonly prescribed antifungal agents for Candida infections: fluconazole, amphotericin B, or caspofungin. Although few of the compounds affected biofilms on their own, seven aspartyl protease inhibitors inhibited biofilm formation when combined with amphotericin B or caspofungin. Furthermore, nine aspartyl protease inhibitors disrupted mature biofilms when combined with caspofungin. These results suggest that the combination of standard antifungal agents together with specific protease inhibitors may be useful in the prevention and treatment of C. albicans biofilm infections.}, } @article {pmid32520698, year = {2020}, author = {Koza, A and Jerdan, R and Cameron, S and Spiers, AJ}, title = {Three biofilm types produced by a model pseudomonad are differentiated by structural characteristics and fitness advantage.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {8}, pages = {707-716}, doi = {10.1099/mic.0.000938}, pmid = {32520698}, issn = {1465-2080}, mesh = {Adaptation, Physiological/genetics ; Bacterial Adhesion ; *Biofilms/growth & development ; Biological Evolution ; Microbial Interactions ; Mutation ; Pseudomonas fluorescens/genetics/growth & development/*physiology ; Rheology ; Viscosity ; }, abstract = {Model bacterial biofilm systems suggest that bacteria produce one type of biofilm, which is then modified by environmental and physiological factors, although the diversification of developing populations might result in the appearance of adaptive mutants producing altered structures with improved fitness advantage. Here we compare the air-liquid (A-L) interface viscous mass (VM) biofilm produced by Pseudomonas fluorescens SBW25 and the wrinkly spreader (WS) and complementary biofilm-forming strain (CBFS) biofilm types produced by adaptive SBW25 mutants in order to better understand the link between these physical structures and the fitness advantage they provide in experimental microcosms. WS, CBFS and VM biofilms can be differentiated by strength, attachment levels and rheology, as well as by strain characteristics associated with biofilm formation. Competitive fitness assays demonstrate that they provide similar advantages under static growth conditions but respond differently to increasing levels of physical disturbance. Pairwise competitions between biofilms suggest that these strains must be competing for at least two growth-limiting resources at the A-L interface, most probably O2 and nutrients, although VM and CBFS cells located lower down in the liquid column might provide an additional fitness advantage through the colonization of a less competitive zone below the biofilm. Our comparison of different SBW25 biofilm types illustrates more generally how varied biofilm characteristics and fitness advantage could become among adaptive mutants arising from an ancestral biofilm-forming strain and raises the question of how significant these changes might be in a range of medical, biotechnological and industrial contexts where diversification and change may be problematic.}, } @article {pmid32520436, year = {2020}, author = {Smith, S and Waters, V and Jahnke, N and Ratjen, F}, title = {Standard versus biofilm antimicrobial susceptibility testing to guide antibiotic therapy in cystic fibrosis.}, journal = {The Cochrane database of systematic reviews}, volume = {6}, number = {6}, pages = {CD009528}, pmid = {32520436}, issn = {1469-493X}, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects/growth & development ; Cystic Fibrosis/*complications ; Female ; Humans ; Male ; Microbial Sensitivity Tests/methods ; Pseudomonas Infections/complications/*drug therapy ; Pseudomonas aeruginosa/*drug effects/physiology ; Randomized Controlled Trials as Topic ; Respiratory Tract Infections/*drug therapy/microbiology ; Sputum/microbiology ; }, abstract = {BACKGROUND: Clinicians typically select the antibiotics used to treat pulmonary infections in people with cystic fibrosis based on the results of antimicrobial susceptibility testing performed on bacteria traditionally grown in a planktonic mode (grown in a liquid). However, there is considerable evidence to suggest that Pseudomonas aeruginosa actually grows in a biofilm (or slime layer) in the airways of people with cystic fibrosis with chronic pulmonary infections. Therefore, choosing antibiotics based on biofilm rather than conventional antimicrobial susceptibility testing could potentially improve response to treatment of Pseudomonas aeruginosa in people with cystic fibrosis. This is an update of a previously published Cochrane Review.

OBJECTIVES: To compare biofilm antimicrobial susceptibility testing-driven therapy to conventional antimicrobial susceptibility testing-driven therapy in the treatment of Pseudomonas aeruginosa infection in people with cystic fibrosis.

SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Most recent search: 07 April 2020. We also searched two ongoing trials registries and the reference lists of relevant articles and reviews. Most recent searches: 07 April 2020 and 05 September 2017.

SELECTION CRITERIA: Randomized controlled trials (RCTs) of antibiotic therapy based on biofilm antimicrobial susceptibility testing compared to antibiotic therapy based on conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infection in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS: Two authors independently selected RCTs, assessed their risk of bias and extracted data from eligible trials. Additionally, the review authors contacted the trial investigators to obtain further information. The quality of the evidence was assessed using the GRADE criteria.

MAIN RESULTS: The searches identified two multicentre, double-blind RCTs eligible for inclusion in the review with a total of 78 participants (adults and children); one RCT was undertaken in people who were clinically stable, the second was in people experiencing pulmonary exacerbations. Both RCTs prospectively assessed whether the use of biofilm antimicrobial susceptibility testing improved microbiological and clinical outcomes in participants with cystic fibrosis who were infected with Pseudomonas aeruginosa. The primary outcome was the change in sputum Pseudomonas aeruginosa density from the beginning to the end of antibiotic therapy. Although the intervention was shown to be safe, the data from these two RCTs did not provide evidence that biofilm susceptibility testing was superior to conventional susceptibility testing either in terms of microbiological or lung function outcomes. One of the trials also measured risk and time to subsequent exacerbation as well as quality of life measures and did not demonstrate any difference between groups in these outcomes. Both RCTs had an overall low risk of bias and the quality of the evidence using GRADE criteria was deemed to be moderate to high for the outcomes selected.

AUTHORS' CONCLUSIONS: The current evidence is insufficient to recommend choosing antibiotics based on biofilm antimicrobial susceptibility testing rather than conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infections in people with cystic fibrosis. Biofilm antimicrobial susceptibility testing may be more appropriate in the development of newer, more effective formulations of drugs which can then be tested in clinical trials.}, } @article {pmid32519201, year = {2021}, author = {Anjum, MM and Patel, KK and Dehari, D and Pandey, N and Tilak, R and Agrawal, AK and Singh, S}, title = {Anacardic acid encapsulated solid lipid nanoparticles for Staphylococcus aureus biofilm therapy: chitosan and DNase coating improves antimicrobial activity.}, journal = {Drug delivery and translational research}, volume = {11}, number = {1}, pages = {305-317}, pmid = {32519201}, issn = {2190-3948}, mesh = {Anacardic Acids ; Biofilms ; *Chitosan ; Deoxyribonucleases ; Drug Carriers ; Excipients ; Humans ; Lipids ; *Nanoparticles ; Particle Size ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus ; }, abstract = {Biofilm mediated bacterial infections are the key factors in the progression of infectious diseases due to the evolution of antimicrobial resistance. Traditional therapy involving antibiotics is not adequate enough for treatment of such infections due to the increased resistance triggered by biofilm. To overcome this challenge, we developed anacardic acid (Ana) loaded solid lipid nanoparticles (SLNs), further coated with chitosan and DNase (Ana-SLNs-CH-DNase). The DNase coating was hypothesized to degrade the e-DNA, while chitosan was coated to yield positively charged SLNs with additional adhesion to biofilms. The SLNs were developed using homogenization method and further evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Drug excipient compatibility was confirmed by using FT-IR study, while encapsulation of Ana in SLNs was confirmed by X-ray diffraction study. The SLNs demonstrated sustained release for up to 24 h and excellent stability at room temperature for up to 3 months. The developed SLNs were found non-toxic against human immortalized keratinocyte (HaCaT) cells while demonstrated remarkably higher antimicrobial efficacy against Staphylococcus aureus. Excellent effect of the developed SLNs on minimum biofilm inhibition concentration and minimum biofilm eradication concentration further confirmed the superiority of the developed formulation strategy. A significant (p < 0.05) reduction in biofilm thickness and biomass, as confirmed by confocal laser scanning microscopy, was observed in the case of developed SLNs in comparison with control. Cumulatively, the results suggest the enhanced efficacy of the developed formulation strategy to overcome the biofilm-mediated antimicrobial resistance. Graphical abstract.}, } @article {pmid32518594, year = {2020}, author = {Jasemi, S and Emaneini, M and Fazeli, MS and Ahmadinejad, Z and Nomanpour, B and Sadeghpour Heravi, F and Sechi, LA and Feizabadi, MM}, title = {Toxigenic and non-toxigenic patterns I, II and III and biofilm-forming ability in Bacteroides fragilis strains isolated from patients diagnosed with colorectal cancer.}, journal = {Gut pathogens}, volume = {12}, number = {}, pages = {28}, pmid = {32518594}, issn = {1757-4749}, abstract = {BACKGROUND: Enterotoxigenic Bacteroides fragilis (ETBF) associated with the initiation and progression of colorectal cancer (CRC) has been alarmingly reported all over the world. In this study, simultaneous investigation of toxigenic and non-toxigenic patterns I, II and III and biofilm formation ability of Bacteroides fragilis isolated from patients with colorectal cancer was performed.

METHODS: Thirty-one patients diagnosed with CRC and thirty-one control subjects were recruited in this study. Specimens were cultured on BBE and BBA culture media. Classical phenotypic identification tests and PCR was performed to verify Bacteroides fragilis presence. Also, biofilm-forming ability and expression of bft gene were assessed under biofilm and planktonic forms.

RESULTS: A total of 68 B.fragilis was isolated from all colorectal tissue, of which 13 isolates (19.1%) (11 isolates from CRC and 2 from normal tissue) were positive for bft gene. The abundance patterns of I, II and III were as follow in descending order; pattern I > pattern III > pattern II in CRC subjects and pattern II > pattern III > pattern I in normal tissues. Also, pattern I showed higher biofilm formation ability compared to other patterns. Toxin expression was significantly reduced in biofilm form comparing with planktonic form.

CONCLUSIONS: Based on our findings, there was a difference between the abundance of patterns I, II, and III and biofilm formation in isolates obtained from CRC and normal tissues. Biofilm formation ability and toxin encoding gene (bft) are two main virulence factors in B. fragilis pathogenicity which require more investigation to treat B. fragilis infections effectively.}, } @article {pmid32518329, year = {2020}, author = {El Zawawy, NA and El-Shenody, RA and Ali, SS and El-Shetehy, M}, title = {A novel study on the inhibitory effect of marine macroalgal extracts on hyphal growth and biofilm formation of candidemia isolates.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {9339}, pmid = {32518329}, issn = {2045-2322}, mesh = {Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development/metabolism/*physiology ; Fungal Polysaccharides/biosynthesis ; Hyphae/*drug effects/*growth & development ; Seaweed/*chemistry ; }, abstract = {Biofilm formation and hyphal growth are considered to be the most serious virulence factors of Candida species in blood causing candidemia infections, which are difficult to treat due to the spread of resistant Candida isolates to most antifungal drugs. Therefore, in this study, we investigated the effect of different types and concentrations of selected macroalgal extracts from Cladostephus spongiosus (Phaeophyta), Laurencia papillosa (Rhodophyta), and Codium arabicum (Chlorophyta) in inhibiting those virulence factors of the isolated Candida. Acetone extract of C. spongiosus (AECS) showed a stronger anticandidal activity against the selected strains than ethanol extract. Candida krusei was the highest biofilm producer among the selected isolates. AECS showed an inhibition of C. krusei biofilm formation as well as a reduction in the viability of preformed biofilms. Also, AECS reduced various sugars in the candidal exo-polysaccaride layer (EPS). Scanning electron microscopy (SEM) and light microscopic images revealed an absence of hyphae and an alteration in the morphology of biofilm cells when treated with AECS. Moreover, AECS downregulated the expression of hyphal specific genes, hyphal wall protein 1 (HWP1), Agglutinin-like protein 1 (ALS1) and fourth secreted aspartyl proteinase (SAP4), which confirmed the inhibitory effect of AECS on hyphal growth and biofilm formation. Gas chromatography-mass spectrophotometer (GC-MS) analysis of AECS showed three major compounds, which were non-existent in the ethanol extract, and might be responsible for the anticandidal activity; these revealed compounds were 4-hydroxy-4-methyl-2-pentanone, n-hexadecenoic acid, and phenol, 2-methoxy-4-(2-propenyl). These active compounds of AECS may be promising for future pharmaceutical applications in the treatment of candidemia.}, } @article {pmid32518194, year = {2020}, author = {Anderton, CR and Mobberley, JM and Cole, JK and Nunez, JR and Starke, R and Boaro, AA and Yesiltepe, Y and Morton, BR and Cory, AB and Cardamone, HC and Hofmockel, KS and Lipton, MS and Moran, JJ and Renslow, RS and Fredrickson, JK and Lindemann, SR}, title = {Nitrogen Source Governs Community Carbon Metabolism in a Model Hypersaline Benthic Phototrophic Biofilm.}, journal = {mSystems}, volume = {5}, number = {3}, pages = {}, pmid = {32518194}, issn = {2379-5077}, abstract = {Increasing anthropogenic inputs of fixed nitrogen are leading to greater eutrophication of aquatic environments, but it is unclear how this impacts the flux and fate of carbon in lacustrine and riverine systems. Here, we present evidence that the form of nitrogen governs the partitioning of carbon among members in a genome-sequenced, model phototrophic biofilm of 20 members. Consumption of NO3 [-] as the sole nitrogen source unexpectedly resulted in more rapid transfer of carbon to heterotrophs than when NH4 [+] was also provided, suggesting alterations in the form of carbon exchanged. The form of nitrogen dramatically impacted net community nitrogen, but not carbon, uptake rates. Furthermore, this alteration in nitrogen form caused very large but focused alterations to community structure, strongly impacting the abundance of only two species within the biofilm and modestly impacting a third member species. Our data suggest that nitrogen metabolism may coordinate coupled carbon-nitrogen biogeochemical cycling in benthic biofilms and, potentially, in phototroph-heterotroph consortia more broadly. It further indicates that the form of nitrogen inputs may significantly impact the contribution of these communities to carbon partitioning across the terrestrial-aquatic interface.IMPORTANCE Anthropogenic inputs of nitrogen into aquatic ecosystems, and especially those of agricultural origin, involve a mix of chemical species. Although it is well-known in general that nitrogen eutrophication markedly influences the metabolism of aquatic phototrophic communities, relatively little is known regarding whether the specific chemical form of nitrogen inputs matter. Our data suggest that the nitrogen form alters the rate of nitrogen uptake significantly, whereas corresponding alterations in carbon uptake were minor. However, differences imposed by uptake of divergent nitrogen forms may result in alterations among phototroph-heterotroph interactions that rewire community metabolism. Furthermore, our data hint that availability of other nutrients (i.e., iron) might mediate the linkage between carbon and nitrogen cycling in these communities. Taken together, our data suggest that different nitrogen forms should be examined for divergent impacts on phototrophic communities in fluvial systems and that these anthropogenic nitrogen inputs may significantly differ in their ultimate biogeochemical impacts.}, } @article {pmid32517335, year = {2020}, author = {Behzadi, P and Urbán, E and Gajdács, M}, title = {Association between Biofilm-Production and Antibiotic Resistance in Uropathogenic Escherichia coli (UPEC): An In Vitro Study.}, journal = {Diseases (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {32517335}, issn = {2079-9721}, abstract = {Urinary tract infections (UTIs) are among the most common infections requiring medical attention worldwide. The production of biofilms is an important step in UTIs, not only from a mechanistic point of view, but this may also confer additional resistance, distinct from other aspects of multidrug resistance (MDR). A total of two hundred and fifty (n = 250) Escherichia coli isolates, originating from clean-catch urine samples, were included in this study. The isolates were classified into five groups: wild-type, ciprofloxacin-resistant, fosfomycin-resistant, trimethoprim-sulfamethoxazole-resistant and extended spectrum β-lactamase (ESBL)-producing strains. The bacterial specimens were cultured using eosine methylene blue agar and the colony morphology of isolates were recorded. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests. Biofilm-formation of the isolates was carried out with the crystal violet tube-adherence method. n = 76 isolates (30.4%) produced large colonies (>3 mm), mucoid variant colonies were produced in n = 135 cases (54.0%), and n = 119 (47.6%) were positive for biofilm formation. The agreement (i.e., predictive value) of mucoid variant colonies in regard to biofilm production in the tube-adherence assay was 0.881 overall. Significant variation was seen in the case of the group of ESBL-producers in the ratio of biofilm-producing isolates. The relationship between biofilm-production and other resistance determinants has been extensively studied. However, no definite conclusion can be reached from the currently available data.}, } @article {pmid32517201, year = {2020}, author = {Olszewska, MA and Gędas, A and Simões, M}, title = {The Effects of Eugenol, Trans-Cinnamaldehyde, Citronellol, and Terpineol on Escherichia coli Biofilm Control as Assessed by Culture-Dependent and -Independent Methods.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {11}, pages = {}, pmid = {32517201}, issn = {1420-3049}, support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; }, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Acyclic Monoterpenes/*pharmacology ; Anti-Infective Agents/*pharmacology ; Antimutagenic Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Escherichia coli O157/drug effects/*growth & development ; Eugenol/*pharmacology ; Terpenes/*pharmacology ; }, abstract = {Bacterial biofilms contribute to problems with preserving food hygiene, jeopardizing any conventional intervention method used by the food industry. Hence, the approach of using essential oil (EO) compounds effective in biofilm control has considerable merit and deserves in-depth research. In this study, the effect of selected EO compounds (eugenol, trans-cinnamaldehyde, citronellol, and terpineol) was assessed on Escherichia coli biofilm control by plate count, resazurin assay, and Syto[®] 9/PI (-/propidium iodide) staining coupled with flow cytometry (FCM) and confocal laser scanning microscopy (CLSM). The selected EO compounds effectively inhibited the growth of planktonic E. coli at low concentrations of 3-5 mM, revealing a high antimicrobial activity. EO compounds markedly interfered with biofilms too, with trans-cinnamaldehyde causing the most prominent effects. Its antibiofilm activity was manifested by a high reduction of cell metabolic activity (>60%) and almost complete reduction in biofilm cell culturability. In addition, almost 90% of the total cells had perturbed cell membranes. Trans-cinnamaldehyde further impacted the cell morphology resulting in the filamentation and, thus, in the creation of a mesh network of cells. Citronellol scored the second in terms of the severity of the observed effects. However, most of all, it strongly prevented native microcolony formation. Eugenol and terpineol also affected the formation of a typical biofilm structure; however, small cell aggregates were still repeatedly found. Overall, eugenol caused the mildest impairment of cell membranes where 50% of the total cells showed the Syto[®] 9+/PI- pattern coupled with healthy cells and another 48% with injured cells (the Syto[®] 9+/PI+). For terpineol, despite a similar percentage of healthy cells, another 45% was shared between moderately (Syto[®] 9+PI+) and heavily (Syto[®] 9-PI+) damaged cells. The results highlight the importance of a multi-method approach for an accurate assessment of EO compounds' action against biofilms and may help develop better strategies for their effective use in the food industry.}, } @article {pmid32516724, year = {2020}, author = {Tran, TN and Kim, DG and Ko, SO}, title = {Efficient removal of 17α-ethinylestradiol from secondary wastewater treatment effluent by a biofilm process incorporating biogenic manganese oxide and Pseudomonas putida strain MnB1.}, journal = {Journal of hazardous materials}, volume = {398}, number = {}, pages = {122810}, doi = {10.1016/j.jhazmat.2020.122810}, pmid = {32516724}, issn = {1873-3336}, mesh = {Biofilms ; Ethinyl Estradiol ; Manganese Compounds ; Oxides ; *Pseudomonas putida ; *Water Purification ; }, abstract = {This study proposes a biofilm process to immobilize biogenic manganese oxide (BMO) and Pseudomonas putida MnB1 (BMO-MnB1), which shows excellent synergistic effects for 17α-ethinylestradiol (EE2) from secondary wastewater treatment effluent (WWTE). Modified granular activated carbon (M-GAC) was used as the packing carrier, inoculated with Pseudomonas putida MnB1 and Mn(II) to form the BMO-MnB1 biofilm. Feasibility tests were performed to compare the EE2 removal efficiency with that of the conventional biofilm process (BAC) for heterogeneous microbial communities. Results show that in the BAC, EE2 was removed mainly by adsorption, with biodegradation contributing only slightly to the overall performance. In contrast, the BMO-MnB1 biofilter outperformed the BAC. Furthermore, less than 4% of the total EE2 removed was extracted from the biofilter medium over 150 days of operation, confirming that EE2 was biodegraded by P. putida MnB1 or chemically oxidized by BMO. Our results suggest that BMO-MnB1 biofilm processes have high potential for practical applications in removal of endocrine disrupting compounds from wastewater effluent.}, } @article {pmid32516672, year = {2020}, author = {Huang, S and Song, Q and Li, Q and Zhang, H and Luo, X and Zheng, Z}, title = {Damage of heavy metals to Vallisneria natans (V. natans) and characterization of microbial community in biofilm.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {225}, number = {}, pages = {105515}, doi = {10.1016/j.aquatox.2020.105515}, pmid = {32516672}, issn = {1879-1514}, mesh = {Antioxidants/metabolism ; Biofilms/*drug effects/growth & development ; Biomass ; Chlorophyll/metabolism ; Cyanobacteria/drug effects/growth & development ; Drug Synergism ; Firmicutes/drug effects/growth & development ; Hydrocharitaceae/*drug effects/microbiology/ultrastructure ; Malondialdehyde/metabolism ; Metals, Heavy/*toxicity ; Microbiota/*drug effects ; Periphyton/drug effects ; Photosynthesis/drug effects ; Water Pollutants, Chemical/*toxicity ; }, abstract = {Heavy metals can cause a significant damage to submerged macrophytes and affect its periphyton biofilms in aquatic environments. This study investigated the effects of heavy metals such as copper (Cu), lead (Pb), cadmium (Cd) and their mixture on physiological and biochemical responses and ultrastructure characteristics of Vallisneria natans (V. natans). Furthermore, differences in structures of microbial communities were observed in biofilms. The results showed that Cu[2+], Pb[2+], Cd[2+] and their mixture could destroy cell structure and photosynthetic system, and directly caused oxidative damage to submerged macrophyte and induced antioxidant enzyme system. In general, biomass and total chlorophyll content of V. natans noticeably decreased, while the activities of superoxide dismutase, peroxidase and catalase were enhanced by heavy metal stress inducement in restricted range, and the malondialdehyde content increased with the aggravation of the damage. The single heavy metal stress played a negative impact, however, the combined stress was not always synergistic effects on plants. High-throughput sequencing analysis suggested that heavy metals changed the abundance and structure of the microbial biofilm community. Proteobacteria and Bacteroidete were the dominant bacteria under heavy metal stress and other species and abundance of bacteria such as Firmicute, Cyanobacteria, Chloroflexi, Actinobacteria, Verrucomicrobia, Acidobacteria, Deinococcus-Thermus, Chlamydiae were also present. These findings provided useful information for further understanding about submerged macrophytes and periphyton biofilms responsed to heavy metal stress in aquatic environments in the future.}, } @article {pmid32515601, year = {2020}, author = {Mizan, MFR and Ashrafudoulla, M and Hossain, MI and Cho, HR and Ha, SD}, title = {Effect of essential oils on pathogenic and biofilm-forming Vibrio parahaemolyticus strains.}, journal = {Biofouling}, volume = {36}, number = {4}, pages = {467-478}, doi = {10.1080/08927014.2020.1772243}, pmid = {32515601}, issn = {1029-2454}, mesh = {Biofilms ; Microbial Sensitivity Tests ; *Oils, Volatile ; Quorum Sensing ; *Vibrio parahaemolyticus ; }, abstract = {In this study, the effect of three essential oils (EOs) - clove oil (CO), thyme oil (TO), and garlic oil (GO), which are generally recognized as safe - on the planktonic growth, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), motility, biofilm formation, and quorum sensing (QS) of Vibrio parahaemolyticus was investigated. All three EOs showed bacteriostatic activity, with MICs in the range 0.02%-0.09% (v/v). CO and TO completely controlled planktonic growth at 0.28% and 0.08% (v/v), which is four times their MIC (4 × MIC), after 10 min, whereas GO completely controlled growth at 0.36% (v/v) (4 × MIC) after treatment for 20 min. V. parahaemolyticus motility was significantly reduced by all three EOs at 4 × MIC (0.28% for CO, 0.08% for TO, and 0.36% for GO), whereas QS was controlled and biofilm formation reduced by all three EOs at 8 × MIC (0.56% for CO, 0.16% for TO, and 0.72% for GO) after 30 min of treatment. These results suggest that CO, TO, and GO have a significant inhibitory effect on V. parahaemolyticus cells in biofilm sand thus represent a promising strategy for improving food safety. These results provide the evidence required to encourage further research into the practical use of the proposed EOs in food preparation processes.}, } @article {pmid32515418, year = {2020}, author = {Carvalho, TS and Halter, JE and Muçolli, D and Lussi, A and Eick, S and Baumann, T}, title = {Pellicle Modification with Casein and Mucin Does Not Promote In Vitro Bacterial Biofilm Formation.}, journal = {Oral health & preventive dentistry}, volume = {18}, number = {1}, pages = {475-483}, doi = {10.3290/j.ohpd.a43351}, pmid = {32515418}, issn = {1757-9996}, mesh = {Biofilms ; *Caseins ; Dental Enamel ; Dental Pellicle ; Humans ; *Mucins ; Saliva ; }, abstract = {PURPOSE: During biofilm formation, bacterial species do not attach directly onto the enamel surface, but rather onto the salivary pellicle. Salivary pellicle modification with casein and mucin can hinder erosive demineralisation of the enamel, but it should also not promote bacterial adhesion. The aim of our study was to assess whether salivary pellicle modification with casein, or mucin, or a mixture of both proteins (casein and mucin) influence bacterial adhesion, biofilm diversity, metabolism and composition, or enamel demineralisation, after incubation in: (a) a single bacterial model; (b) a five-species biofilm model; or (c) biofilm reformation using the five-species biofilm model after removal of initial biofilm with toothbrushing.

MATERIALS AND METHODS: Enamel specimens were prepared from human molars. Whole-mouth stimulated human saliva was used for pellicle formation. Four pellicle modification groups were established: control (non-modified pellicle); casein - modified with 0.5% casein; mucin - modified with 0.5% mucin; casein and mucin - modified with 0.5% casein and 0.5% mucin. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 6 h or 24 h.

RESULTS: After 24 h incubation in the five-species biofilm model, the mucin group presented significantly lower biofilm mass than the control (p = 0.028) and the casein and mucin (p = 0.030) groups. No other differences between the groups were observed in any of the other experimental procedures.

CONCLUSION: Pellicle modification with casein and mucin does not promote in vitro bacterial biofilm formation.}, } @article {pmid32512756, year = {2020}, author = {Kaoukab-Raji, A and Biskri, L and Allaoui, A}, title = {Inactivation of the sfgtr4 Gene of Shigella flexneri Induces Biofilm Formation and Affects Bacterial Pathogenicity.}, journal = {Microorganisms}, volume = {8}, number = {6}, pages = {}, pmid = {32512756}, issn = {2076-2607}, support = {FRSM: 3.4.623.06 and 3.4556.11//Belgian FRSM (: conventions: 3.4.623.06 and 3.4556.11)/ ; }, abstract = {Biofilm formation is a significant cause for the environmental persistence of foodborne pathogens. This phenomenon remains misunderstood in Shigella flexneri whose pathogenicity is mainly associated with the virulence plasmid pWR100. Sequence analysis of the latter predicts a putative lipopolysaccharides (LPS) glycosyltransferase (Gtr) encoded by Sfgtr4, which is the second gene of the SfpgdA-orf186-virK-msbB2 locus. We demonstrated here that purified SfGtr4 exhibited a Gtr activity in vitro by transferring glucose to lipid A. To establish the role of SfGtr4 in virulence, we generated a Sfgtr4 mutant and assessed its phenotype in vitro. Sfgtr4 mutant significantly reduced HeLa cells invasion without impairing type III effectors secretion, increased susceptibility to lysozyme degradation, and enhanced bacterial killing by polymorphonuclear neutrophils (PMNs). SfGtr4 is related to proteins required in biofilm formation. We established conditions whereby wild-type Shigella formed biofilm and revealed that its appearance was accelerated by the Sfgtr4 mutant. Additional phenotypical analysis revealed that single SfpdgA and double SfpgdA-Sfgtr4 mutants behaved similarly to Sfgtr4 mutant. Furthermore, a molecular interaction between SfGtr4 and SfPgdA was identified. In summary, the dual contribution of SfGtr4 and SfPgdA to the pathogenicity and the regulation biofilm formation by S. flexneri was demonstrated here.}, } @article {pmid32512247, year = {2020}, author = {Leelanarathiwat, K and Katsuta, Y and Katsuragi, H and Watanabe, F}, title = {Antibacterial activity of blue high-power light-emitting diode-activated flavin mononucleotide against Staphylococcus aureus biofilm on a sandblasted and etched surface.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101855}, doi = {10.1016/j.pdpdt.2020.101855}, pmid = {32512247}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Flavin Mononucleotide ; Methylene Blue/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; *Staphylococcus aureus ; }, abstract = {BACKGROUND: Because of high affinity to the titanium implant surface, Staphylococcus aureus (S. aureus) has been reported as key microorganism that cause the peri-implantitis, even though it is not the typical periodontal pathogenic bacterial strain. The aim of this study was to evaluate the antibacterial property of the aPDT device, using blue high-power LED light activated flavin mononucleotide, comparing to the previously proven aPDT method using methylene blue and red laser on S. aureus biofilm.

METHODS: Commercial pure titanium grade 4 modified surface with SLA were used to form S. aureus biofilm for 48 h. Two aPDT systems were used in this study; 1) HELBO®Blue Photosensitizer (Bredent medical), which is methylene blue (MB) activated by 670-nm red diode laser and 2) FotoSan® Blue agent Gel (CMS Dental), which contains flavin mononucleotide (FMN) activated by FotoSan® BLUE LAD (Light Activated Disinfection) light. The antibacterial tests were performed by total viable count, crystal violet assay, and direct observation methods.

RESULTS: Using the light activated-PS, the log reduction in CFU/mL compared to non-treatment was 1.23 ± 0.19 log10 and 1.23 ± 0.12 log10 (about 93 % of reduction) for MB and FMN, respectively. The significant difference in the reduction could be determined when comparing with using only light (p < 0.01). Regarding two aPDT systems, the decrease in amount of bacteria after treatment was not significantly different (p > 0.05).

CONCLUSION: The antibacterial activities of aPDT using blue high-power LED light activated flavin mononucleotide on S. aureus biofilm was comparable to those of previous research supporting aPDT using photoactivated MB.}, } @article {pmid32510928, year = {2020}, author = {Rouillard, KR and Markovetz, MR and Bacudio, LG and Hill, DB and Schoenfisch, MH}, title = {Pseudomonas aeruginosa Biofilm Eradication via Nitric Oxide-Releasing Cyclodextrins.}, journal = {ACS infectious diseases}, volume = {6}, number = {7}, pages = {1940-1950}, doi = {10.1021/acsinfecdis.0c00246}, pmid = {32510928}, issn = {2373-8227}, mesh = {Biofilms ; *Cyclodextrins ; Humans ; Nitric Oxide ; *Pseudomonas aeruginosa ; Tobramycin ; }, abstract = {Pseudomonas aeruginosa is the main contributor to the morbidity and mortality of cystic fibrosis (CF) patients. Chronic respiratory infections are rarely eradicated due to protection from CF mucus and the biofilm matrix. The composition of the biofilm matrix determines its viscoelastic properties and affects antibiotic efficacy. Nitric oxide (NO) can both disrupt the physical structure of the biofilm and eradicate interior colonies. The effects of a CF-like growth environment on P. aeruginosa biofilm susceptibility to NO were investigated using parallel plate macrorheology and particle tracking microrheology. Biofilms grown in the presence of mucins and DNA contained greater concentrations of DNA in the matrix and exhibited concomitantly larger viscoelastic moduli compared to those grown in tryptic soy broth. Greater viscoelastic moduli correlated with increased tolerance to tobramycin and colistin. Remarkably, NO-releasing cyclodextrins eradicated all biofilms at the same concentration. The capacity of NO-releasing cyclodextrins to eradicate P. aeruginosa biofilms irrespective of matrix composition suggests that NO-based therapies may be superior antibiofilm treatments compared to conventional antibiotics.}, } @article {pmid32510869, year = {2020}, author = {Liu, Z and Hong, CJ and Yang, Y and Dai, L and Ho, CL}, title = {Advances in Bacterial Biofilm Management for Maintaining Microbiome Homeostasis.}, journal = {Biotechnology journal}, volume = {15}, number = {10}, pages = {e1900320}, doi = {10.1002/biot.201900320}, pmid = {32510869}, issn = {1860-7314}, support = {DWKF20190001//Shenzhen Institutes of Advanced Technology External Funds/ ; 2018KTSCX200//Guangdong Innovative Projects for the Characteristics of General Colleges and Universities/ ; 2019ZT08Y191//Guangdong Innovative and Entrepreneurial Research Team Program/ ; }, mesh = {Anti-Bacterial Agents ; Bacteria ; *Biofilms ; Homeostasis ; Humans ; *Microbiota ; }, abstract = {Certain microbial biofilm in the human-microbiota community can negatively impact the host microbiome. This gives rise to various methods to prevent the formation of biofilms or to facilitate biofilm dispersal from surfaces and tissues in the host. Despite all these efforts, these persistent microbial biofilms on surfaces and in the host tissue can result in health problems to the host and its microbiome. It is the adaptive behavior of microbes within the biofilm that confers on these tenacious microbes the resistance to harsh environments, antibiotic treatments, and the ability to evade the host immune system. In this review, the approaches to combat microbial biofilm in the last decade are discussed. The biochemical pathway regulating biofilm formation is first discussed, followed by the discussion of the three approaches to combat biofilm formation: physical, chemical, and biological approaches. The advances in these approaches have given rise to methods of effectively dispersing the microbial biofilm and preventing the adherence of these microbial communities altogether. As there are numerous approaches to target biofilm, in this review the attempt is to provide insights on how these approaches have been used to modulate the host-microbiome by looking at the individual strengths and weaknesses.}, } @article {pmid32510398, year = {2020}, author = {Ng, JCY and Chiu, JMY}, title = {Changes in biofilm bacterial communities in response to combined effects of hypoxia, ocean acidification and nutrients from aquaculture activity in Three Fathoms Cove.}, journal = {Marine pollution bulletin}, volume = {156}, number = {}, pages = {111256}, doi = {10.1016/j.marpolbul.2020.111256}, pmid = {32510398}, issn = {1879-3363}, mesh = {*Aquaculture ; Biofilms ; Humans ; Hydrogen-Ion Concentration ; Hypoxia ; Nutrients ; RNA, Ribosomal, 16S ; *Seawater ; }, abstract = {Anthropogenic nutrient enrichment results in hypoxia, ocean acidification and elevated nutrients (HOAN) in coastal environments throughout the world. Here, we examined the composition of biofilm bacterial communities from a nutrient-excessive fish farm with low dissolved oxygen (DO) and pH levels using 16S rRNA gene sequencing. HOAN was accompanied by higher bacterial diversity and richness, and resulted in an altered community composition than the control site. HOAN resulted in more Flavobacteriales, Rhizobiales, Epsilonproteobacteria and Vibrionales, but less Oceanospirillales and Alteromonadales. Photobacterium sp. and Vibrio sp. were mostly found to be exclusive to HOAN conditions, suggesting that HOAN could possibly proliferate the presence of these potential pathogens. Our study suggests the complexity of bacterial communities to hypoxia and acidification in response to increased nutrient loads, along with identities of nutrient, oxygen and pH-susceptible bacterial groups that are most likely affected under this ocean trend.}, } @article {pmid32509022, year = {2020}, author = {Li, T and Wang, G and Yin, P and Li, Z and Zhang, L and Tang, P}, title = {Adaptive expression of biofilm regulators and adhesion factors of Staphylococcus aureus during acute wound infection under the treatment of negative pressure wound therapy in vivo.}, journal = {Experimental and therapeutic medicine}, volume = {20}, number = {1}, pages = {512-520}, pmid = {32509022}, issn = {1792-0981}, abstract = {Negative pressure wound therapy (NPWT) is gaining acceptance as a physical therapy for a wide variety of infected wounds. To gain insight into the response of bacteria to NPWT in vivo, the adaptive expression of biofilm regulators and adhesion factors of Staphylococcus aureus (S. aureus), the most frequently isolated pathogen in the clinic, during acute wound infection was investigated. A 3 cm full-thickness dermal wound was created on each side of a rabbit back and inoculated with green fluorescent protein-labeled S. aureus. NPWT was initiated at 6 h post inoculation, with the wound on the contralateral side as the untreated self-control. The wounds were subjected to a 28 day observation period. Histological analysis, laser scanning confocal microscopy and scanning electron microscopy revealed a transition of S. aureus to a free-living phenotype in tissues treated with NPWT, compared with microcolonies in untreated wounds. Viable bacteria counts showed a modest reduction in the bioburden of NPWT group on day 8 (P<0.001), with ~1x10[6] colony-forming units/g tissue. Transcript analysis of biofilm- and colonization-related genes were investigated using reverse transcription-quantitative PCR on postoperative days 1, 2, 4 and 8. The poly-beta-1,6-N-acetyl-D-glucosamine synthase locus and holin-like protein CidA/antiholin-like protein LrgA network were less active in the NPWT group compared with the untreated control group. Accordingly, the expression profile switched to an elevated expression of the adhesive factors UDP-phosphate N-acetylglucosaminyl 1-phosphate transferase (at days 0-4) and fibronectin-binding protein A and iron-regulated surface determinant protein A at >4 days during both stages of colonization. Meanwhile, low expression levels of the effector molecule (RNAIII) of the accessory gene regulator type I (agr) system was detected in NPWT group, suggesting that the bacterial density in NPWT-treated wounds was under the threshold for agr activation, thus not leading to an active and invasive infection. The wounds treated by NPWT healed completely on day 28, compared with an average of an 8.11% defect area in the control group (P<0.001). The results of the current study indicated that S. aureus responds to NPWT by regulating gene expression, manifesting a decrease in biofilm formation and an increase in bacterial colonization in vivo, which potentially benefits the wound repair and healing process.}, } @article {pmid32508783, year = {2020}, author = {Wang, Z and Shen, Y and Haapasalo, M}, title = {Dynamics of Dissolution, Killing, and Inhibition of Dental Plaque Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {964}, pmid = {32508783}, issn = {1664-302X}, abstract = {The present study aims to establish a standardized model that makes it possible to evaluate the dynamic dissolution of biofilm, killing of biofilm microbes and inhibition of growth of biofilm by disinfecting solutions. Biofilm was grown from dental plaque bacteria on collagen-coated hydroxyapatite (HA) disks for 3 days or 3 weeks under anaerobic conditions. Biofilms were stained with the LIVE/DEAD viability stain and subjected to sterile water, 2% sodium hypochlorite (NaOCl), 6% NaOCl, or 2% chlorhexidine (CHX) for 32 min. Dynamic change in fluorescence on bacterial cells and extracellular polymeric substance (EPS) during the exposure was analyzed using Alexa Fluor 647-labeled dextran conjugate and a live-cell imaging confocal laser scanning microscopy (LC-CLSM). The biofilm structures after treatments were visualized by scanning electron microscopy (SEM). The treated biofilms on HA disks were collected and subjected to colony forming unit (CFU) counting. Another set of sterile HA disks were coated with CHX prior to the monitoring of plaque biofilm growth for 12 h. The LC-CLSM results showed that NaOCl dissolved biofilm effectively, more so at a higher concentration and longer exposure time. Six percent NaOCl was the most effective at dissolving and killing bacteria (e.g., 99% bacterial reduction in 3-day-old biofilm and 95% bacterial reduction in 3-week-old biofilm in 32 min) followed by 2% NaOCl and CHX. Sodium hypochlorite dissolved over 99.9% of the EPS whereas CHX only slightly reduced the EPS biovolume in 32 min. CFU results indicated that the dispersed biofilm bacteria are more resistant than planktonic bacteria to disinfectants. SEM showed the disruption of biofilm after exposures to CHX and NaOCl. The use of 2% CHX and sterile water did not result in biofilm dissolution. However, prior exposure of the HA disks to 2 and 0.2% CHX for 3 min prevented biofilm from growing on the HA disk surfaces for at least 12 h. This new platform has the potential to aid in a better understanding of the antibiofilm properties of oral disinfectants.}, } @article {pmid32508761, year = {2020}, author = {Li, W and Wang, JJ and Qian, H and Tan, L and Zhang, Z and Liu, H and Pan, Y and Zhao, Y}, title = {Insights Into the Role of Extracellular DNA and Extracellular Proteins in Biofilm Formation of Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {813}, pmid = {32508761}, issn = {1664-302X}, abstract = {The extracellular polymeric substances (EPS) construct the three-dimensional (3-D) structure of biofilms, but their respective roles are still not clear. Therefore, this study aimed to illuminate the role of key chemical components [extracellular DNA (eDNA), extracellular proteins, and carbohydrates] of EPS in biofilm formation of Vibrio parahaemolyticus. The correlations between each key chemical component and biofilm formation were first determined, showing that the biofilm formation of V. parahaemolyticus was strongly positively correlated with both eDNA and protein content (P < 0.01), but not with carbohydrates. Subsequently, individual DNase I or protease K treatment markedly reduced the initial adhesion and structural stability of the formed biofilms by hydrolyzing the eDNA or extracellular proteins, but did not induce significant dispersion of mature biofilms. However, the combination of DNase I and protease K treatment induced the obvious dispersion of the mature biofilms through the concurrent destruction of eDNA and extracellular proteins. The analysis at a structural level showed that the collapse of biofilms was mainly attributed to the great damage of the loop configuration of eDNA and the secondary structure of proteins caused by the enzyme treatment. Therefore, this study provides a deep understanding of the role of key chemical components of EPS in biofilm development of V. parahaemolyticus, which may give a new strategy to develop environmentally friendly methods to eradicate the biofilms in food industry.}, } @article {pmid32507630, year = {2020}, author = {López, ALR and Lee, MR and Ortiz, BJ and Gastfriend, BD and Whitehead, R and Lynn, DM and Palecek, SP}, title = {Corrigendum to "Preventing S. aureus biofilm formation on titanium surfaces by the release of antimicrobial β-peptides from polyelectrolyte multilayers" Acta Biomaterialia 2019, 93, 50-62.}, journal = {Acta biomaterialia}, volume = {111}, number = {}, pages = {429}, doi = {10.1016/j.actbio.2020.05.003}, pmid = {32507630}, issn = {1878-7568}, support = {R33 AI127442/AI/NIAID NIH HHS/United States ; }, } @article {pmid32506835, year = {2020}, author = {Panchatcharam, BS and Cooksley, CM and Ramezanpour, M and Vediappan, RS and Bassiouni, A and Wormald, PJ and Psaltis, AJ and Vreugde, S}, title = {Staphylococcus aureus biofilm exoproteins are cytotoxic to human nasal epithelial barrier in chronic rhinosinusitis.}, journal = {International forum of allergy & rhinology}, volume = {10}, number = {7}, pages = {871-883}, doi = {10.1002/alr.22566}, pmid = {32506835}, issn = {2042-6984}, mesh = {Biofilms ; Cells, Cultured ; Chronic Disease ; Humans ; Nasal Mucosa ; *Sinusitis ; *Staphylococcus aureus ; }, abstract = {BACKGROUND: Chronic rhinosinusitis patients (CRS) suffer from chronic inflammation of the sinus mucosa associated with chronic relapsing infections. Mucosal biofilms, associated with Staphylococcus aureus, have been implicated as a cause. We compared the effect of exoproteins secreted from clinical isolates of S aureus from CRS patients in planktonic and biofilm form on the nasal epithelial barrier.

METHODS: Clinical S aureus isolates from 39 CRS patients were grown in planktonic and biofilm forms and their exoproteins concentrated. These were applied to primary human nasal epithelial cells grown at the air-liquid interface. Transepithelial electrical resistance, permeability of flourescein isothiocyanate-dextrans, and cytotoxicity were measured. Structure and expression of tight junctions zona occludens-1, and claudin-1 proteins were assessed by electron microscopy and immunofluorescence. The Wilcoxon signed rank test was used for statistical analyses.

RESULTS: S aureus biofilm exoproteins showed dose- and time-dependent reduction of transepithelial electrical resistance, increased cell toxicity, and increased permeability (p < 0.001) compared with equal concentrations of planktonic cultures. Discontinuity in zona occludens-1 and claudin-1 immunofluorescence was confirmed as disrupted tight junctions on electron microscopy.

CONCLUSION: S aureus biofilm exoproteins disrupt the mucosal barrier structure in a time- and dose-dependent manner and are toxic. Damage to the mucosal barrier by S aureus biofilm exoproteins may play a major role in CRS etiopathogenesis.}, } @article {pmid32505890, year = {2020}, author = {Kragh, ML and Muchaamba, F and Tasara, T and Truelstrup Hansen, L}, title = {Cold-shock proteins affect desiccation tolerance, biofilm formation and motility in Listeria monocytogenes.}, journal = {International journal of food microbiology}, volume = {329}, number = {}, pages = {108662}, doi = {10.1016/j.ijfoodmicro.2020.108662}, pmid = {32505890}, issn = {1879-3460}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cold Shock Proteins and Peptides/genetics/*metabolism ; Desiccation ; Food Handling ; *Food Microbiology ; Gene Deletion ; Listeria monocytogenes/*physiology ; Sequence Deletion ; }, abstract = {Listeria monocytogenes is a foodborne pathogen whose biofilm formation and desiccation tolerance may contribute to its survival in the food industry. L. monocytogenes possesses three cold-shock domain family proteins (CspA, CspB and CspD) known to be essential for adaptation against various food-relevant stress conditions including cold growth. The role of Csps in desiccation tolerance and biofilm formation was investigated in csp mutants as well as twenty-one other wild-type (WT) strains. Mutants with a single (ΔcspA) or multiple (ΔcspAB, ΔcspAD and ΔcspABD) deletions of csp genes, in a desiccation sensitive WT background (L. monocytogenes EGD-e) were immotile and exhibited an elevated desiccation tolerance compared to the parent strain. However, deletion of cspA in the more desiccation resistant food and outbreak related L. monocytogenes strains 568 and 08-5578 had no impact on desiccation tolerance although compared to the parent strains the mutants were also immotile. A correlation between lower motility and higher desiccation tolerance was observed among the 20 WT strains (Spearman rank correlation, rs = -0.56, p = 0.01), although exceptions occurred indicating that multiple factors influence the diverse desiccation tolerance among L. monocytogenes strains. Expression of cspA was upregulated in WT EGD-e, 568 and 08-5578 strains after desiccation for seven days, while the 568 and 08-5578 ΔcspA mutants expressed elevated levels of cspD and cspB (>30 fold higher) compared to their WTs. This indicates that upregulation of the other csps compensates for the deleted cspA gene. Although biofilm formation was improved in all EGDe csp mutants relative to the WT strain, the opposite was observed for 568 and 08-5578 WT strains and their cspA deletion mutants. Only motile strains formed biofilm in the peg lid assay but a significant negative correlation (rs = -0.60, p = 0.01) was seen between higher motility and higher biofilm formation of WT strains. In conclusion, the survival of L. monocytogenes strains in the food processing environment may depend on the control of motility, which is a necessity for biofilm formation but disadvantageous for desiccation survival.}, } @article {pmid32505537, year = {2020}, author = {Porter, GC and Tompkins, GR and Schwass, DR and Li, KC and Waddell, JN and Meledandri, CJ}, title = {Anti-biofilm activity of silver nanoparticle-containing glass ionomer cements.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {8}, pages = {1096-1107}, doi = {10.1016/j.dental.2020.05.001}, pmid = {32505537}, issn = {1879-0097}, mesh = {Biofilms ; Color ; Glass Ionomer Cements ; Materials Testing ; *Metal Nanoparticles ; *Silver/pharmacology ; }, abstract = {OBJECTIVE: To develop a silver nanoparticle (AgNP) formulation for incorporation into glass ionomer cements (GICs) which minimises biofilm growth on restoration surfaces.

METHODS: GICs, Fuji IX, Ketac Molar, and Riva Selfcure were modified with 6, 10 and 24 μg per GIC capsule of α-lipoic acid-capped AgNPs. Monoculture biofilms of Streptococcus mutans were cultured (72 h) on GIC specimens (n = 3) and biofilm accumulation was quantified using a viability stain with confocal laser scanning microscopy. Compression strength and flexural strength (CS & FS) were measured according to ISO 9917-1:2007 (n = 8, n = 25). GIC colour was measured at 0, 1, and 14 days following AgNP incorporation using a digital spectrophotometer. Silver release from AgNP-modified GIC specimens was monitored at 1, 3, 7 and 14 days using inductively coupled plasma-mass spectrometry.

RESULTS: AgNP-modified Fuji IX demonstrated the greatest reduction in biofilm accumulation, with 10 μg Ag/capsule inhibiting biofilm formation by 99%. Ketac Molar and Riva Selfcure required 24 μg Ag/capsule to achieve 78% biofilm reduction. AgNP-modified GICs demonstrated significantly higher CS and FS than sintered silver-containing GICs, and possessed equivalent or higher strength values when compared to unmodified GICs. The colour shades of AgNP-modified GICs were more comparable to VITA shades of non-modified GICs than were sintered silver-containing GICs. The silver (≥99.6%) remained within the GIC for at least two weeks following incorporation.

SIGNIFICANCE: AgNP-modified GICs exhibited significant antibiofilm activity and retained mechanical properties equivalent or superior to non-modified GICs. AgNP-modified GICs could reduce bacterial colonisation on and around restorations thereby reducing restoration failure caused by secondary caries.}, } @article {pmid32504487, year = {2020}, author = {Wu, J and Yang, Q and Jiang, X and Fan, Y and Zhang, Y and Huang, R}, title = {Oxyresveratrol promotes biofilm formation, cell attachment and aggregation of Streptococcus gordonii in the presence of sucrose.}, journal = {FEMS microbiology letters}, volume = {367}, number = {12}, pages = {}, doi = {10.1093/femsle/fnaa090}, pmid = {32504487}, issn = {1574-6968}, mesh = {Anti-Infective Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Drug Interactions ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Stilbenes/*pharmacology ; Streptococcus gordonii/*drug effects/genetics ; Sucrose/*pharmacology ; }, abstract = {Streptococcus gordonii is a commensal colonizer of oral cavity that initiates the formation of dental plaque. Oxyresveratrol is a natural purification from plants with antibacterial effects on various oral bacteria including Streptococcus mutans. The aim of this study was to investigate the effects of oxyresveratrol on S. gordonii. The basic viability, biofilm formation and cell aggregation of S. gordonii treated with oxyresveratrol were investigated. Oxyresveratrol dose-dependently inhibited the growth of S. gordonii in the absence of sucrose. However, in the presence of sucrose, it promoted biofilm formation under MIC. Both the biofilm formation and extracellular polysaccharides synthesis reached the maximum level at ½ MIC (250 μg/mL) oxyresveratrol. The gene expressions of abpA, abpB, scaA, gtfG, hsa, cshA, cshB, ccpA, srtA and sspB were upregulated when treated with 62.5 and 125 μg/mL oxyresveratrol. A total eight of the ten genes were significantly upregulated at 250 μg/mL oxyresveratrol except abpB and sspB, which were downregulated at 250 μg/mL without significance. In conclusion, oxyresveratrol has dual-effects on S. gordonii. Considering its specific biofilm suppressive effect on S. mutans, it might be a candidate for bacterial interspecies modulator applied in caries prevention.}, } @article {pmid32503907, year = {2020}, author = {Guan, C and Che, F and Zhou, H and Li, Y and Li, Y and Chu, J}, title = {Effect of Rubusoside, a Natural Sucrose Substitute, on Streptococcus mutans Biofilm Cariogenic Potential and Virulence Gene Expression In Vitro.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {16}, pages = {}, pmid = {32503907}, issn = {1098-5336}, mesh = {Biofilms/*drug effects/growth & development ; Dental Caries/microbiology/*prevention & control ; Diterpenes, Kaurane ; *Gene Expression ; *Genes, Bacterial ; Glucosides ; Polysaccharides, Bacterial/*metabolism ; Streptococcus mutans/*drug effects/genetics/physiology ; Virulence ; Virulence Factors/*genetics ; }, abstract = {Dental caries is a biofilm-mediated disease in which Streptococcus mutans is the main pathogenic microorganism, and its incidence is closely related to sucrose. Rubusoside is a natural nonnutritive sweetener isolated from Rubus suavissimus S. Lee. This study was designed to determine the effect of this sucrose substitute on the cariogenic properties and virulence gene expression of S. mutans biofilms. S. mutans was exposed to brain heart infusion (BHI) medium (as a control), 1% sucrose-supplemented medium, 1% rubusoside-supplemented medium, and 1% xylitol-supplemented medium. The growth curve of the biofilm was monitored by crystal violet staining, and the pH was measured every 24 h. After 5 days, the biofilms formed on the glass coverslips were recovered to determine the biomass (dry weight and total amount of soluble proteins), numbers of CFU, and amounts of intra- and extracellular polysaccharides. Biofilm structural imaging was performed using a scanning electron microscope (SEM). Virulence gene expression (gtfB, gtfC, gtfD, ftf, spaP, gbpB, ldh, atpF, vicR, and comD) was determined by reverse transcription-quantitative PCR. Growth in rubusoside resulted in lower levels of acid production than observed during growth in sucrose, xylitol, and the control, while it also reduced the level of biofilm accumulation and bacterial viability and even reduced the level of production of extracellular polysaccharides. By SEM, the levels of biofilm formation and extracellular matrix during growth in rubusoside were lower than these levels during growth in sucrose and xylitol. From the perspective of virulence genes, growth in rubusoside and xylitol significantly inhibited the expression of virulence genes compared with their levels of expression after growth in sucrose. Among these genes, gtfB, gtfC, gbpB, ldh, and comD downregulation was found with growth in rubusoside compared with their expression with growth in xylitol. Therefore, rubusoside appears to be less potentially cariogenic than sucrose and xylitol and may become an effective sucrose substitute for caries prevention. Further studies are needed to deepen these findings.IMPORTANCE Dental caries is a major public health challenge and places heavy biological, social, and financial burdens on individuals and health care systems. To palliate the deleterious effect of sucrose on the virulence factors of S. mutans, massive commercial efforts have been oriented toward developing products that may act as sucrose substitutes. Rubusoside, a natural sucrose substitute, is a plant extract with a high level of sweetness. Although some studies have shown that rubusoside does not produce acids or inhibit the growth of S. mutans, little attention has been paid to its effect on dental biofilm and the underlying mechanisms. Our study focuses on the effect of rubusoside on the formation and structure of biofilms and the expression of virulence genes. The results confirm that rubusoside can inhibit accumulation, bacterial viability, polysaccharide production by the biofilm, and related gene expression. These results provide further insight into the cariogenicity of S. mutans biofilms and demonstrate a new perspective for studying the impact of sucrose substitutes on caries.}, } @article {pmid32503624, year = {2020}, author = {Liu, Y and Hannig, M}, title = {Vinegar inhibits the formation of oral biofilm in situ.}, journal = {BMC oral health}, volume = {20}, number = {1}, pages = {167}, pmid = {32503624}, issn = {1472-6831}, support = {SFB 1027//German Research Foundation, DFG, SFB 1027/International ; }, mesh = {*Acetic Acid/pharmacology ; Animals ; *Biofilms ; Cattle ; Dental Enamel ; Dental Pellicle ; Microscopy, Electron, Transmission ; Saliva ; }, abstract = {BACKGROUND: Vinegar has been recognized as an effective antimicrobial agent for long. This study intended to elucidate the effect of commercially available vinegar on in situ pellicle formation and existing 24-h biofilms.

METHODS: In situ biofilm formation took place on bovine enamel slabs mounted in individual splints and exposed intraorally over 3 min and 24 h, respectively. After 5 s rinsing with vinegar, all samples were analyzed via fluorescence microscopy (FM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, salivary samples were collected and analyzed via FM. Samples with water rinsing served as controls.

RESULTS: Vinegar caused destruction of the pellicle. Compared to the control group, vinegar rinsing reduced the outer globular layer of the pellicle (p < 0.001), and resulted in formation of subsurface pellicle. Also, vinegar rinsing could reduce bacterial viability and disrupt the 24-h biofilm. Total bacteria amount of saliva samples decreased remarkably (p < 0.001) after vinegar rinsing within 30 min. Reduction of bacterial viability was observed even 120 min after vinegar rinsing in both biofilm and saliva sample (p < 0.001).

CONCLUSION: This in situ study reveals that rinsing with vinegar for only 5 s alters the pellicle layer resulting in subsurface pellicle formation. Furthermore, vinegar rinsing will destruct mature (24-h) biofilms, and significantly reduce the viability of planktonic microbes in saliva, thereby decreasing biofilm formation.}, } @article {pmid32503535, year = {2020}, author = {Sun, Y and Wen, S and Zhao, L and Xia, Q and Pan, Y and Liu, H and Wei, C and Chen, H and Ge, J and Wang, H}, title = {Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in Northeast China.}, journal = {BMC veterinary research}, volume = {16}, number = {1}, pages = {176}, pmid = {32503535}, issn = {1746-6148}, support = {No. 17XG10//the "Academic Backbone" Project of Northeast Agricultural University/ ; 31672532//National Natural Science Foundation of China/ ; 201910224139//SIPT Program/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/growth & development ; China ; Diarrhea/microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Female ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Proteus mirabilis/*drug effects/*genetics/pathogenicity ; Virulence/genetics ; }, abstract = {BACKGROUND: The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016.

RESULTS: Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in the biofilm producer group was significantly higher than that in the non-producer group. Biofilm production was significantly associated with the expression of ureC, zapA, rsmA, hmpA, mrpA, atfA, and pmfA (P < 0.05). The results of drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin (P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice (P > 0.05).

CONCLUSION: Our findings suggested that a high level of multidrug resistance in P. mirabilis isolates obtained from diarrhetic animals in northeast China. The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.}, } @article {pmid32502632, year = {2020}, author = {Vijayakumar, K and Bharathidasan, V and Manigandan, V and Jeyapragash, D}, title = {Quebrachitol inhibits biofilm formation and virulence production against methicillin-resistant Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104286}, doi = {10.1016/j.micpath.2020.104286}, pmid = {32502632}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Inositol/analogs & derivatives ; *Methicillin-Resistant Staphylococcus aureus ; Virulence ; }, abstract = {The present study evaluated the quebrachitol (QBC) antibiofilm and antivirulence potential against methicillin-resistant Staphylococcus aureus (MRSA). QBC inhibited MRSA biofilm formation at concentration dependent manner without affecting the bacterial growth. Then, QBC biofilm efficacy was confirmed with light and confocal laser scanning microscopy analysis. QBC treatment significantly inhibited the biofilm formation on stainless steel, titanium and silicone surfaces. Besides, QBC treatment significantly reduced the MRSA virulence productions such as lipase and hemolysis. Moreover, it reduced MRSA survival rate in the presence of hydrogen peroxide. QBC treatment inhibited the MRSA adherence on hydrophobic, hydrophilic, collagen coating and fibrinogen coating surfaces. As well as it significantly reduced the autolysin and bacterial aggregation progress. The real-time PCR analysis revealed the ability of QBC downregulated the virulence genes expression including global regulator sarA, agr and polysaccharide intracellular adhesion (PIA) encode ica. The cumulative results of the present study suggest that QBC as a potential agent to combat against MRSA pathogenesis.}, } @article {pmid32502284, year = {2020}, author = {Pereira, TC and Dijkstra, RJB and Petridis, X and van der Meer, WJ and Sharma, PK and de Andrade, FB and van der Sluis, LWM}, title = {The influence of time and irrigant refreshment on biofilm removal from lateral morphological features of simulated root canals.}, journal = {International endodontic journal}, volume = {53}, number = {12}, pages = {1705-1714}, pmid = {32502284}, issn = {1365-2591}, support = {//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; //Abel Tasman Talent Program/ ; //European Society of Endodontology/ ; //Graduate School of Medical Sciences of the University of Groningen/ ; }, mesh = {*Biofilms ; *Dental Pulp Cavity ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite/pharmacology ; Time Factors ; }, abstract = {AIM: To evaluate the effect of irrigant refreshment and exposure time of a 2% sodium hypochlorite solution (NaOCl) on biofilm removal from simulated lateral root canal spaces using two different flow rates.

METHODOLOGY: A dual-species biofilm was formed by a Constant Depth Film Fermenter (CDFF) for 96 h in plug inserts with anatomical features resembling an isthmus or lateral canal-like structures. The inserts were placed in a root canal model facing the main canal. NaOCl 2% and demineralized water (control group) were used as irrigant solutions. Both substances were applied at a flow rate of 0.05 and 0.1 mL s[-1] . The samples were divided into three groups with zero, one or two refreshments in a total exposure time of 15 min. A three-way analysis of variance (anova) was performed to investigate the interaction amongst the independent variables and the effect of consecutive irrigant refreshment on percentage of biofilm removal. A Tukey post hoc test was used to evaluate the effect of each independent variable on percentage biofilm removal in the absence of statistically significant interactions.

RESULTS: For the lateral canal, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time (P = 0.005). There was no significant effect in biofilm removal between the consecutive irrigant refreshments measured in the same biofilm. For the isthmus, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time; both NaOCl and a high flow rate removed significantly more biofilm when the exposure time was analysed (P = 0.018 and P = 0.029, respectively). Evaluating the effect of consecutive irrigant refreshment on the same biofilm, 2% NaOCl, 0.1 mL s[-1] flow rate and one or two refreshments removed significant more biofilm (P = 0.04, 0.034 and 0.003, <0.001, respectively).

CONCLUSIONS: In this model, refreshment did not improve biofilm removal from simulated lateral root canal spaces. NaOCl removed more biofilm from the lateral canal- and isthmus-like structure. A higher flow rate removed significantly more biofilm from the isthmus-like structure. There was always remaining biofilm left after the irrigation procedures.}, } @article {pmid32500253, year = {2020}, author = {Khosravi, M and Mirzaie, A and Kashtali, AB and Noorbazargan, H}, title = {Antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of novel synthesized gold nanoparticles coated Anthemis atropatana extract against multidrug- resistant Klebsiella pneumoniae strains.}, journal = {Archives of microbiology}, volume = {202}, number = {8}, pages = {2105-2115}, doi = {10.1007/s00203-020-01930-y}, pmid = {32500253}, issn = {1432-072X}, mesh = {Anthemis/*chemistry ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/drug effects ; Drug Resistance, Multiple/*drug effects ; Enzyme Activation/drug effects ; Gene Expression Regulation/drug effects ; Gold/chemistry/*pharmacology ; HEK293 Cells ; Humans ; Klebsiella pneumoniae/*drug effects ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/*pharmacology ; Urease/metabolism ; }, abstract = {In this study, the antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of green synthesized gold nanoparticles (AuNPs) coated Anthemis atropatana extract against multidrug- resistant (MDR) Klebsiella pneumoniae strains were evaluated. The green synthesized AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform infrared spectroscopy (FTIR). Then, antibacterial, anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities of AuNPs were investigated using micro-dilation, Congored agar, microtiter plate and MIC of ethidium bromide methods, respectively. Subsequently, the expression of mrkA, wzm and acrB genes was evaluated using quantitative Real-Time PCR (qRT-PCR). The synthesized AuNPs exhibited antibacterial activity against MDR strains of K. pneumoniae (minimum inhibitory concentration (MIC) of 6.25-50 µg/ml), as well as showed significant anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities against MDR strains. AuNPs showed significant inhibition against jack-bean urease and down-regulated the expression of mrkA, wzm and acrB genes. Moreover, the in vitro cytotoxic activity confirmed by MTT assay on the HEK-293 normal cell line showed negligible cytotoxicity. Thus, the present study suggests the potential use of AuNPs in the development of novel therapeutics for the prevention of biofilm-associated K. pneumoniae infections.}, } @article {pmid32498595, year = {2021}, author = {Mirzaei, B and Babaei, R and Valinejad, S}, title = {Staphylococcal Vaccine Antigens related to biofilm formation.}, journal = {Human vaccines & immunotherapeutics}, volume = {17}, number = {1}, pages = {293-303}, pmid = {32498595}, issn = {2164-554X}, mesh = {Anti-Bacterial Agents ; Biofilms ; Humans ; *Methicillin-Resistant Staphylococcus aureus/genetics ; *Staphylococcal Infections/prevention & control ; *Staphylococcal Vaccines ; Staphylococcus aureus/genetics ; Staphylococcus epidermidis ; }, abstract = {The number and frequency of multidrug-resistant (MDR) strains as a frequent cause of nosocomial infections have increased, especially for Methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, in part due to device-related infections. The transition to antibiotic-resistance in related bacterial genes and the capability for immune escape have increased the sustainability of biofilms produced by these bacteria. The formation and changes in biofilms have been suggested as a target to prevent or treat staphylococcal infections. Thus, this study reviews the development of candidate staphylococcal vaccines by database searching, and evaluates the immunogenicity and efficacy profiles of bacterial components involved in biofilms. The literature suggests that using common staphylococcal vaccine antigens and multivalent vaccines should further enhance vaccine efficacy.}, } @article {pmid32498472, year = {2020}, author = {Ni, P and Wang, L and Deng, B and Jiu, S and Ma, C and Zhang, C and Almeida, A and Wang, D and Xu, W and Wang, S}, title = {Combined Application of Bacteriophages and Carvacrol in the Control of Pseudomonas syringae pv. actinidiae Planktonic and Biofilm Forms.}, journal = {Microorganisms}, volume = {8}, number = {6}, pages = {}, pmid = {32498472}, issn = {2076-2607}, support = {MH235//Shanghai Minhang Science and Technology Commission/ ; }, abstract = {Pseudomonas syringae pv. actinidiae (Psa) is the causative agent of the bacterial canker of kiwifruit (Actinidia spp.). Phage therapy has been suggested as a viable alternative approach to controlling this disease, but its efficacy is limited by the emergence of phage-resistant mutants. Carvacrol is an essential oil that may be useful for the control of Psa. Combination therapies can be used to overcome resistance development. Here, the combination of phages (single phage suspensions of phages PN05 and PN09, and a cocktail of both phages) and carvacrol was investigated in controlling Psa planktonic and biofilm forms in vitro. The phage therapy alone (with phages PN05 and PN09), and the carvacrol alone (minimum inhibitory concentration 2.0 mg/mL), inhibited Psa growth, but the combined effect of both therapies was more effective. The phages alone effectively inhibited Psa growth for 24 h, but Psa regrowth was observed after this time. The carvacrol (2.0 mg/mL) alone prevented the biofilm formation for 48 h, but did not destroy the pre-formed biofilms. The combined treatment, phages and carvacrol (2.0 mg/mL), showed a higher efficacy, preventing Psa regrowth for more than 40 h. In conclusion, the combined treatment with phages and carvacrol may be a promising, environment-friendly and cost-effective approach to controlling Psa in the kiwifruit industry.}, } @article {pmid32497775, year = {2020}, author = {Pourhajibagher, M and Miri-Moosavi, RS and Chiniforush, N and Safaraei, Y and Arian-Kia, S and Lalegani, MR and Bazarjani, F and Bahador, A}, title = {Anti-biofilm activity of Chlorella-mediated light activated disinfection: Ex vivo inhibition of intracanal mature Enterococcus faecalis biofilms via application of natural product.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101853}, doi = {10.1016/j.pdpdt.2020.101853}, pmid = {32497775}, issn = {1873-1597}, mesh = {Biofilms ; *Biological Products ; *Chlorella ; Dental Pulp Cavity ; Disinfection ; Enterococcus faecalis ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Root Canal Irrigants ; Sodium Hypochlorite ; }, abstract = {BACKGROUND: This study aimed to evaluate the effects of light-activated disinfection (LAD) as a strategy for optimizing root canal disinfection using Chlorella (Chlo) as a natural photosensitizer against Enterococcus faecalis biofilms ex vivo.

MATERIALS AND METHODS: The physical and chemical stability and absorption spectra of Chlo were determined. The mature microbial biofilm of E. faecalis was formed in root canals of 70 freshly extracted single-rooted premolars. After determining the minimum inhibitory concentration (MIC) of Chlo using the agar dilution testing, E. faecalis biofilms were exposed in the following groups (n = 10): 1- Chlo at a concentration of 2× MIC, 1- Chlo at a concentration of 4× MIC, 3- Diode laser, 4-2× MIC dose of Chlo-mediated LAD, 5-4× MIC dose of Chlo-mediated LAD, 6-0.2 % chlorohexidine (CHX), and 7- control group (E. faecalis biofilms without exposure to any photosensitizer and light source). The quantitative and qualitative evaluations of E. faecalis biofilms were done using counts of colony forming units (CFUs) and scanning electron microscope (SEM) and fluorescence microscope analysis, respectively.

RESULTS: According to the results, the MIC of Chlo was 125 μg/mL, which inhibited the growth of E. faecalis. To evaluate the anti-biofilm effects of Chlo, the 2× and 4× MICs of Chlo (250 and 500 μg/mL, respectively) were used in the current study. The 4× MIC dose (500 μg/mL) of Chlo-mediated LAD was significantly more effective compared to other groups (P < 0.05), while the lowest percentage of dead cells was detected in the diode laser irradiation group. In addition, there was no significant difference in the log10 CFU of E. faecalis between the biofilm treated with 500 μg/mL Chlo-mediated LAD (1.27 ± 0.05) versus 0.2 % CHX (1.10 ± 0.06) (P < 0.05). As Moreover, SEM and fluorescence microscope images of the microbial biofilms showed that the highest percentage of dead bacteria was found in the 500 μg/mL Chlo-mediated LAD group.

CONCLUSIONS: The results of this study suggest that Chlo-mediated LAD can be used as an adjuvant therapy to eliminate the E. faecalis biofilms in the root canal system.}, } @article {pmid32496982, year = {2021}, author = {Thaarup, IC and Bjarnsholt, T}, title = {Current In Vitro Biofilm-Infected Chronic Wound Models for Developing New Treatment Possibilities.}, journal = {Advances in wound care}, volume = {10}, number = {2}, pages = {91-102}, doi = {10.1089/wound.2020.1176}, pmid = {32496982}, issn = {2162-1918}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*physiology ; Candidiasis/*metabolism/microbiology ; Cells, Cultured ; Chronic Disease ; Fibroblasts/*drug effects/metabolism/microbiology ; Gram-Positive Bacteria/*physiology ; Gram-Positive Bacterial Infections/*metabolism/microbiology ; Humans ; Keratinocytes/*drug effects/metabolism/microbiology ; Pseudomonas Infections/*metabolism/microbiology ; Pseudomonas aeruginosa/*physiology ; Skin/cytology ; Wound Healing/drug effects ; Wound Infection/*metabolism/microbiology ; }, abstract = {Significance: The prevalence of chronic wounds is increasing worldwide. The most recent estimates suggest that up to 2% of the population in the industrialized countries is affected. Recent Advances: During the past few decades, bacterial biofilms have been elucidated as one of the primary reasons why chronic wounds fail to heal. Critical Issues: There is a lack of direct causation and evidence of the role that biofilms play in persistent wounds, which complicates research on new treatment options, since it is still unknown which factors dominate. For this reason, several different in vitro wound models that mimic the biofilm infections observed in chronic wounds and other chronic infections have been created. These different models are, among other purposes, used to test a variety of wound care products. However, chronic wounds are highly complex, and several different factors must be taken into consideration along with the infection, including physiochemical and human-supplemented factors. Furthermore, the limitations of using in vitro models, such as the lack of a responsive immune system should always be given due consideration. Future Directions: Present understandings of all the elements and interactions that take place within chronic wounds are incomplete. As our insight of in vivo chronic wounds continues to expand, so too must the in vitro models used to mimic these infections evolve and adapt to new knowledge.}, } @article {pmid32496187, year = {2020}, author = {Pezzoni, M and Pizarro, RA and Costa, CS}, title = {Role of quorum sensing in UVA-induced biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {8}, pages = {735-750}, doi = {10.1099/mic.0.000932}, pmid = {32496187}, issn = {1465-2080}, mesh = {4-Butyrolactone/analogs & derivatives/genetics/metabolism ; Biofilms/growth & development/*radiation effects ; Gene Expression Regulation, Bacterial/radiation effects ; Genes, Bacterial/genetics ; Guanosine Tetraphosphate/genetics/metabolism ; Mutation ; Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas aeruginosa/*physiology/radiation effects ; Quorum Sensing/genetics/*physiology/radiation effects ; Transcription, Genetic/radiation effects ; Ultraviolet Rays ; }, abstract = {Pseudomonas aeruginosa, a versatile bacterium present in terrestrial and aquatic environments and a relevant opportunistic human pathogen, is largely known for the production of robust biofilms. The unique properties of these structures complicate biofilm eradication, because they make the biofilms very resistant to diverse antibacterial agents. Biofilm development and establishment is a complex process regulated by multiple regulatory genetic systems, among them is quorum sensing (QS), a mechanism employed by bacteria to regulate gene transcription in response to population density. In addition, environmental factors such as UVA radiation (400-315 nm) have been linked to biofilm formation. In this work, we further investigate the mechanism underlying the induction of biofilm formation by UVA, analysing the role of QS in this phenomenon. We demonstrate that UVA induces key genes of the Las and Rhl QS systems at the transcriptional level. We also report that pelA and pslA genes, which are essential for biofilm formation and whose transcription depends in part on QS, are significantly induced under UVA exposure. Finally, the results demonstrate that in a relA strain (impaired for ppGpp production), the UVA treatment does not induce biofilm formation or QS genes, suggesting that the increase of biofilm formation due to exposure to UVA in P. aeruginosa could rely on a ppGpp-dependent QS induction.}, } @article {pmid32494168, year = {2020}, author = {Zhang, DX and Li, Y and Yang, XQ and Su, HY and Wang, Q and Zhang, ZH and Liu, YC and Tian, CL and Cui, CC and Liu, MC}, title = {In vitro Antibiotic Susceptibility, Virulence Genes Distribution and Biofilm Production of Staphylococcus aureus Isolates from Bovine Mastitis in the Liaoning Province of China.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {1365-1375}, pmid = {32494168}, issn = {1178-6973}, abstract = {PURPOSE: The aim of this study was to identify the subtype, characterize the antimicrobial resistance, determine the virulence gene distribution, and analyze the biofilm production of Staphylococcus aureus isolates from bovine mastitis milk samples in the Liaoning Province of China.

MATERIALS AND METHODS: In total, 56 Staph. aureus isolates were collected and identified in this study; the isolates were divided into different spa types based on the sequence of the polymorphic X region of the spa gene. Additionally, antimicrobial susceptibility was investigated using the broth microdilution method, and 18 virulence genes were detected using PCR. Biofilm formation was measured by spectrophotometry with crystal violet staining and observed using confocal laser scanning microscopy.

RESULTS: There were 12.12% (56/462) milk samples that were positive for Staph. aureus. These isolates were nonsusceptible to sulfamethoxazole (100%), penicillin (76.9%), daptomycin (76.79%), clindamycin (69.64%), and oxacillin (60.71%); however, the majority of the isolates (80.4%) were susceptible to amoxicillin/clavulanate. The predominant virulence genes encoded the cytotoxins, hla (94.64%) and hlb (89.29%), and the adhesion factors clfA (89.29%), clfB (89.29%), and fnbB (80.36%). Comparatively, virulence genes related to other adhesion factors such as cna (8.93%) and enterotoxins, such as seg (26.79%), sea (16.07%), seb (7.14%), and sec (7.14%) were detected at relatively lower rates. The following eight spa types were identified: t267 (35.84%), t730 (22.64%), t518 (15.09%), t1190 (11.32%), t1456 (9.43%), t224 (1.88%), t9129 (1.88%), and t177 (1.88%). The highest biofilm production was observed for t267. Staph. aureus exhibited various patterns of biofilm formation, with the biofilm often being associated with a tower-shaped structure or a thicker biofilm.

CONCLUSION: Our results indicated that Staph. aureus isolates from dairy cows with mastitis in the Liaoning Province of China were non-susceptible to sulfamethoxazole, penicillin, daptomycin, oxacillin, and clindamycin. Additionally, the most prevalent subtype was t267, which displayed resistance to multiple antimicrobial agents and harbored several virulence genes, including clfA, clfB, fnbB, hla, and hlb.}, } @article {pmid32493549, year = {2020}, author = {Bernegossi, J and Fontana, CR and Caiaffa, KS and Duque, C and Chorilli, M}, title = {Inhibitory Effect of a KSL-W Peptide-Loaded Poloxamer 407-Based Microemulsions for Buccal Delivery on Fusobacterium nucleatum Biofilm.}, journal = {Journal of biomedical nanotechnology}, volume = {16}, number = {3}, pages = {390-397}, doi = {10.1166/jbn.2020.2896}, pmid = {32493549}, issn = {1550-7033}, mesh = {Antimicrobial Cationic Peptides ; Biofilms ; *Fusobacterium nucleatum ; Poloxamer ; Scattering, Small Angle ; X-Ray Diffraction ; }, abstract = {KSL-W peptide has demonstrated antibacterial and antifungal activity and inhibitory effects against oral biofilm. This study aimed to check out the effect of chlorhexidine (CLX) or KSL-W peptide-loaded poloxamer 407-based microemulsions for buccal delivery on Fusobacterium nucleatum (F. nucleatum) biofilm. The formulation (F) containing 10% copolymer poloxamer 407 dispersion (1%), 40% oleic acid and 50% PPG-5-CETETH-20 was characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, bioadhesive and syringeability; and in the treatment of a biofilm produced by F. nucleatum. The darkfield images obtained by PLM and the SAXS curves with an extended peak indicated that the system was characteristic of microemulsions. In a continuous analysis, microemulsions exhibited Newtonian behavior. In frequency, the oscillatory analysis profile presented predominantly viscous behavior. Bioadhesive force detected in the analysis of F (7.4 ± 1.81 mN˙ s) and syringeability (17.83± 5.97 N · mm) being adequate values for buccal administration. After 4 h, KSL-W-loaded F shown over 20% higher effectiveness than chlorhexidine-loaded microemulsions. In conclusion, the KSL-W-loaded microemulsions showed a considerable reduction in F. nucleatum biofilm formation and presented promising structural properties for buccal drug delivery.}, } @article {pmid32493365, year = {2020}, author = {Engel, AS and Kranz, HT and Schneider, M and Tietze, JP and Piwowarcyk, A and Kuzius, T and Arnold, W and Naumova, EA}, title = {Biofilm formation on different dental restorative materials in the oral cavity.}, journal = {BMC oral health}, volume = {20}, number = {1}, pages = {162}, pmid = {32493365}, issn = {1472-6831}, mesh = {Bacterial Adhesion/*physiology ; *Biofilms ; Dental Enamel/microbiology ; Dental Implants/*microbiology ; *Dental Materials ; Dental Plaque/microbiology ; Humans ; Mouth/*microbiology ; Surface Properties ; }, abstract = {BACKGROUND: Bacterial biofilms adhere to all tissues and surfaces in the oral cavity. Oral biofilms are responsible for the decay of human dental structures and the inflammatory degeneration of the alveolar bone. Moreover, oral biofilms on artificial materials influence the lifespan of dental prostheses and restoratives.

METHODS: To investigate in vivo oral biofilm formation and growth, five different dental restorative materials were analyzed and compared to human enamel. The roughness of the materials and the human enamel control probe were measured at the start of the study. The dental restorative materials and the human enamel control probe were placed in dental splints and worn for 3 h, 24 h and 72 h.

RESULTS: Scanning electron microscopy (SEM) revealed major differences between oral biofilm formation and growth on the materials compared to those on human enamel. Microbiological analyses showed that bacterial strains differed between the materials. Significant differences were observed in the roughness of the dental materials.

CONCLUSIONS: It can be concluded that material roughness affects biofilm formation on dental surfaces and restoratives, but other factors, such as surface charge, surface energy and material composition, may also have an influence.}, } @article {pmid32493283, year = {2020}, author = {Ohsumi, T and Takenaka, S and Sakaue, Y and Suzuki, Y and Nagata, R and Hasegawa, T and Ohshima, H and Terao, Y and Noiri, Y}, title = {Adjunct use of mouth rinses with a sonic toothbrush accelerates the detachment of a Streptococcus mutans biofilm: an in vitro study.}, journal = {BMC oral health}, volume = {20}, number = {1}, pages = {161}, pmid = {32493283}, issn = {1472-6831}, support = {23592795//Japan Society for the Promotion of Science/International ; 16K20451//Japan Society for the Promotion of Science/International ; }, mesh = {Bacterial Adhesion ; Bacterial Load ; Biofilms/drug effects ; Chlorhexidine ; Dental Enamel/*microbiology ; Humans ; Mouthwashes/*pharmacology ; Streptococcus mutans/*drug effects ; Toothbrushing/*instrumentation/methods ; Ultrasonics/*instrumentation ; }, abstract = {BACKGROUND: The aim of this in vitro study was to examine the possible enhancement of the biofilm peeling effect of a sonic toothbrush following the use of an antimicrobial mouth rinse.

METHODS: The biofilm at a noncontact site in the interdental area was treated by sound wave convection with the test solution or by immersion in the solution. The biofilm peeling effect was evaluated by determining the bacterial counts and performing morphological observations. A Streptococcus mutans biofilm was allowed to develop on composite resin discs by cultivation with stirring at 50 rpm for 72 h. The specimens were then placed in recesses located between plastic teeth and divided into an immersion group and a combination group. The immersion group was treated with phosphate buffer, chlorhexidine digluconate Peridex™ (CHX) mouth rinse or Listerine® Fresh Mint (EO) mouth rinse. The combination group was treated with CHX or EO and a sonic toothbrush.

RESULTS: The biofilm thickness was reduced by approximately one-half compared with the control group. The combination treatment produced a 1 log reduction in the number of bacteria compared to the EO immersion treatment. No significant difference was observed in the biofilm peeling effect of the immersion group compared to the control group.

CONCLUSIONS: The combined use of a sonic toothbrush and a mouth rinse enhanced the peeling of the biofilm that proliferates in places that are difficult to reach using mechanical stress.}, } @article {pmid32492906, year = {2020}, author = {Ionescu, AC and Cazzaniga, G and Ottobelli, M and Garcia-Godoy, F and Brambilla, E}, title = {Substituted Nano-Hydroxyapatite Toothpastes Reduce Biofilm Formation on Enamel and Resin-Based Composite Surfaces.}, journal = {Journal of functional biomaterials}, volume = {11}, number = {2}, pages = {}, pmid = {32492906}, issn = {2079-4983}, abstract = {Background: Toothpastes containing nano-hydroxyapatite (n-HAp) substituted with metal ions provide calcium and phosphate ions to dental hard tissues, reducing demineralization, and promoting remineralization. Few data are available about the effect of these bioactive compounds on oral microbiota. Methods: This in vitro study evaluated the influence of two commercially-available substituted n-HAp-based toothpastes (α: Zn-carbonate substituted n-HAp; β: F, Mg, Sr-carbonate substituted n-HAp) on early colonization (EC, 12 h) and biofilm formation (BF, 24 h) by oral microbiota. Controls were brushed with distilled water. Artificial oral microcosm and Streptococcus mutans biofilms were developed using human enamel and a resin-based composite (RBC) as adherence surfaces. Two test setups, a shaking multiwell plate and a modified drip-flow reactor (MDFR), were used to simulate clinical conditions during the night (low salivary flow and clearance) and daytime, respectively. Energy-dispersive X-ray spectrometry (EDS) was used to evaluate specimens' surfaces after toothpaste treatment. Fluoride release from β toothpaste was evaluated. Viable adherent biomass was quantified by MTT assay, and biofilms' morphology was highlighted using confocal microscopy. Results: EDS showed the presence of remnants from the tested toothpastes on both adherence surfaces. β toothpaste showed significantly lower EC and BF compared to control using the artificial oral microcosm model, while α toothpaste showed lower EC and BF compared to control, but higher EC and BF compared to β toothpaste. The effect shown by β toothpaste was, to a minimal extent, due to fluoride release. Interestingly, this result was seen on both adherence surfaces, meaning that the tested toothpastes significantly influenced EC and BF even on RBC surfaces. Furthermore, the effect of toothpaste treatments was higher after 12 h than 24 h, suggesting that toothbrushing twice a day is more effective than brushing once. Conclusions: The efficacy of these treatments in reducing microbial colonization of RBC surfaces may represent a promising possibility in the prevention of secondary caries.}, } @article {pmid32492772, year = {2020}, author = {Kostoglou, D and Protopappas, I and Giaouris, E}, title = {Common Plant-Derived Terpenoids Present Increased Anti-Biofilm Potential against Staphylococcus Bacteria Compared to a Quaternary Ammonium Biocide.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {32492772}, issn = {2304-8158}, abstract = {The antimicrobial actions of three common plant-derived terpenoids (i.e., carvacrol, thymol and eugenol) were compared to those of a typical quaternary ammonium biocide (i.e., benzalkonium chloride; BAC), against both planktonic and biofilm cells of two widespread Staphylococcus species (i.e., S. aureus and S. epidermidis). The minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each compound against the planktonic cells of each species were initially determined, together with their minimum biofilm eradication concentrations (MBECs). Various concentrations of each compound were subsequently applied, for 6 min, against each type of cell, and survivors were enumerated by agar plating to calculate log reductions and determine the resistance coefficients (Rc) for each compound, as anti-biofilm effectiveness indicators. Sessile communities were always more resistant than planktonic ones, depending on the biocide and species. Although lower BAC concentrations were always needed to kill a specified population of either cell type compared to the terpenoids, for the latter, the required increases in their concentrations, to be equally effective against the biofilm cells with respect to the planktonic ones, were not as intense as those observed in the case of BAC, presenting thus significantly lower Rc. This indicates their significant anti-biofilm potential and advocate for their further promising use as anti-biofilm agents.}, } @article {pmid32492592, year = {2020}, author = {Hülsen, T and Sander, EM and Jensen, PD and Batstone, DJ}, title = {Application of purple phototrophic bacteria in a biofilm photobioreactor for single cell protein production: Biofilm vs suspended growth.}, journal = {Water research}, volume = {181}, number = {}, pages = {115909}, doi = {10.1016/j.watres.2020.115909}, pmid = {32492592}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; Biomass ; Bioreactors ; Dietary Proteins ; *Photobioreactors ; *Proteobacteria ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Single cell protein (SCP), has been proposed as alternative to effectively upgrade and recycle organics and nutrients from wastewater. Biomass recovery is a critical issue, and recovery as a biofilm is effective in comparison with sedimentation of suspended biomass. This study aims to determine the applicability of purple phototrophic bacteria (PPB) biofilm on infra-red irradiated, submerged surfaces for the treatment of pre-settled red meat processing wastewater, and SCP generation. PPB removed up to 66% of COD and 42% of TN and TP during batch operation with total areal productivities between 15 and 20 gVS m[-2] d[-1] achieved. More than 60% of the total biomass grew attached (as biofilm) with the remainder being suspended. The biofilm can be harvested at around 160 gTS L[-1] with high protein (>96 g L[-1]) and low ash contents (>4.0% compared to >30% in the wastewater). The compositions of attached and suspended biomass differed significantly, where the suspended fraction resembled the wastewater composition (e.g. in terms of inert components). The PPB community was similar in the suspended and biofilm fractions while the biofilm had higher relative abundance of PPB representatives (57% vs 43%). A consistent product composition is highly relevant for the manufacturer and ultimately determines the value as feed, feed additive, or supplement.}, } @article {pmid32492459, year = {2020}, author = {Meng, J and Xu, J and Chen, J}, title = {The role of osmoregulated periplasmic glucans in the biofilm antibiotic resistance of Yersinia enterocolitica.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104284}, doi = {10.1016/j.micpath.2020.104284}, pmid = {32492459}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics ; Biofilms ; Drug Resistance, Microbial ; Glucans ; *Yersinia enterocolitica/genetics ; }, abstract = {The formation of biofilms by bacteria is of great significance because it involves many physiological changes that serve to protect the cells from various stresses. One of the best-known biofilm-specific properties of bacteria is that bacteria that grow in biofilms are generally more resistant to antibiotics than their planktonic counterparts. In a previous study, osmoregulated periplasmic glucans (OPGs), catalyzed by the opgGH operon, were identified and found to function in Rcs signalling in Yersinia enterocolitica. In this study, the possible contribution of OPGs to antimicrobial resistance of Y. enterocolitica biofilms were investigated, and the results showed that OPGs, especially when overexpressed, conferred a high level of biofilm resistance to two different classes of antibiotics onto Y. enterocolitica. Subsequent analysis revealed that OPGs regulated the biofilm architecture in Y. enterocolitica by promoting the bacteria to form large cell aggregates. Moreover, the opgGH genes in biofilms showed higher expression than in planktonic cultures. OPGs were required to induce the expression of genes related to flagella, extracellular polysaccharide, and c-di-GMP biosynthesis in Y. enterocolitica biofilms and this effect was more significant when OPGs were overproduced. The current investigation showed an extension in the biological role of OPGs in Y. enterocolitica and provided a strong theoretical basis to further study this resistance mechanism at the molecular level to identify new drug targets or disinfectants for the treatment of infections caused by Y. enterocolitica within biofilms.}, } @article {pmid32491277, year = {2020}, author = {Earl, C and Arnaouteli, S and Bamford, NC and Porter, M and Sukhodub, T and MacPhee, CE and Stanley-Wall, NR}, title = {The majority of the matrix protein TapA is dispensable for Bacillus subtilis colony biofilm architecture.}, journal = {Molecular microbiology}, volume = {114}, number = {6}, pages = {920-933}, doi = {10.1111/mmi.14559}, pmid = {32491277}, issn = {1365-2958}, support = {BB/M013774/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N022254/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 097818/Z/11/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Amino Acid Sequence ; Bacillus subtilis/*genetics/*growth & development/metabolism ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Extracellular Matrix Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Sequence Deletion ; }, abstract = {Biofilm formation is a co-operative behaviour, where microbial cells become embedded in an extracellular matrix. This biomolecular matrix helps manifest the beneficial or detrimental outcome mediated by the collective of cells. Bacillus subtilis is an important bacterium for understanding the principles of biofilm formation. The protein components of the B. subtilis matrix include the secreted proteins BslA, which forms a hydrophobic coat over the biofilm, and TasA, which forms protease-resistant fibres needed for structuring. TapA is a secreted protein also needed for biofilm formation and helps in vivo TasA-fibre formation but is dispensable for in vitro TasA-fibre assembly. We show that TapA is subjected to proteolytic cleavage in the colony biofilm and that only the first 57 amino acids of the 253-amino acid protein are required for colony biofilm architecture. Through the construction of a strain which lacks all eight extracellular proteases, we show that proteolytic cleavage by these enzymes is not a prerequisite for TapA function. It remains unknown why TapA is synthesised at 253 amino acids when the first 57 are sufficient for colony biofilm structuring; the findings do not exclude the core conserved region of TapA having a second role beyond structuring the B. subtilis colony biofilm.}, } @article {pmid32489278, year = {2020}, author = {Bin, C and Al-Dhabi, NA and Esmail, GA and Arokiyaraj, S and Arasu, MV}, title = {Potential effect of Allium sativum bulb for the treatment of biofilm forming clinical pathogens recovered from periodontal and dental caries.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {6}, pages = {1428-1434}, pmid = {32489278}, issn = {1319-562X}, abstract = {Biofilm producing clinical bacterial isolates were isolated from periodontal and dental caries samples and identified as, Lactobacillus acidophilus, Streptococcus sanguis, S. salivarius, S. mutansand Staphylococcus aureus. Among the identified bacterial species, S. aureus and S. mutansshowed strong biofilm producing capacity. The other isolated bacteria, Streptococcus sanguis, S. salivarius showed moderate biofilm formation. These pathogens were subjected for the production of extracellular polysaccharides (EPS) in nutrient broth medium and the strain S. aureus synthesized more amounts of EPS (610 ± 11.2 µg/ml) than S. sanguis (480 ± 5.8 µg/ml).EPS production was found to be less in S. salivarius (52 ± 3.8 µg/ml).The solvent extract of A. sativum bulb showed the phytochemicals such as, carbohydrate, total protein, alkaloids, saponins, flavonoids, tannins and sterioids. The solvent extract of A. sativum bulb showed wide ranges of activity against the selected dental pathogens. The difference in antibacterial activity of the solvent extract revealed differences in solubility of phytochemicals in organic solvents. Ethanol extract was highly active againstS. aureus (25 ± 2 mm). The Minimum Inhibitory Concentration (MIC) of crude garlic bulb varied widely and this clearly showed that bacteria exhibits different level of susceptibility to secondary metabolites. MIC value ranged between 20 ± 2 mg/ml and 120 ± 6 mg/ml and Minimum Bactericidal Concentration (MBC) value ranged from 60 ± 5 mg/l to 215 ± 7 mg/ml. To conclude, A. sativum bulb can be effectively used to treat periodontal and dental caries infections.}, } @article {pmid32488138, year = {2020}, author = {Warraich, AA and Mohammed, AR and Perrie, Y and Hussain, M and Gibson, H and Rahman, A}, title = {Evaluation of anti-biofilm activity of acidic amino acids and synergy with ciprofloxacin on Staphylococcus aureus biofilms.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {9021}, pmid = {32488138}, issn = {2045-2322}, support = {BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Aspartic Acid/administration & dosage/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects ; Ciprofloxacin/*pharmacology ; Colony Count, Microbial ; Dose-Response Relationship, Drug ; Drug Synergism ; Glutamic Acid/administration & dosage/*pharmacology ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Acidic amino acids, aspartic acid (Asp) and glutamic acid (Glu) can enhance the solubility of many poorly soluble drugs including ciprofloxacin (Cip). One of the mechanisms of resistance within a biofilm is retardation of drug diffusion due to poor penetration across the matrix. To overcome this challenge, this work set to investigate novel counter ion approach with acidic amino acids, which we hypothesised will disrupt the biofilm matrix as well as simultaneously improve drug effectiveness. The anti-biofilm activity of D-Asp and D-Glu was studied on Staphylococcus aureus biofilms. Synergistic effect of combining D-amino acids with Cip was also investigated as a strategy to overcome anti-microbial resistance in these biofilms. Interestingly at equimolar combinations, D-Asp and D-Glu were able to significantly disperse (at 20 mM and 40 mM) established biofilms and inhibit (at 10 mM, 20 mM and 40 mM) new biofilm formation in the absence of an antibiotic. Moreover, our study confirmed L-amino acids also exhibit anti-biofilm activity. The synergistic effect of acidic amino acids with Cip was observed at lower concentration ranges (<40 mM amino acids and <90.54 µM, respectively), which resulted in 96.89% (inhibition) and 97.60% (dispersal) reduction in CFU with exposure to 40 mM amino acids. Confocal imaging indicated that the amino acids disrupt the honeycomb-like extracellular DNA (eDNA) meshwork whilst also preventing its formation.}, } @article {pmid32487404, year = {2020}, author = {Baig, U and Ansari, MA and Gondal, MA and Akhtar, S and Khan, FA and Falath, WS}, title = {Single step production of high-purity copper oxide-titanium dioxide nanocomposites and their effective antibacterial and anti-biofilm activity against drug-resistant bacteria.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {113}, number = {}, pages = {110992}, doi = {10.1016/j.msec.2020.110992}, pmid = {32487404}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Copper/*chemistry ; Drug Resistance, Bacterial/*drug effects ; HCT116 Cells ; HEK293 Cells ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Nanocomposites/*chemistry/toxicity ; Particle Size ; Pseudomonas aeruginosa/drug effects/physiology ; Titanium/*chemistry ; }, abstract = {In the present research work, copper oxide-titanium dioxide nanocomposites were synthesized for the first time using advanced pulsed laser ablation in liquid (PLAL) technique for disinfection of drug-resistant pathogenic waterborne biofilm-producing bacterial strains. For this, a series of copper oxide-titanium dioxide nanocomposites were synthesized by varying the composition of copper oxide (5%, 10%, and 20%) with titanium dioxide. The pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were characterized by advanced instrumental techniques. XRD, TEM, FE-SEM, EDX, elemental mapping and XPS analysis results consistently revealed the successful formation of copper oxide-titanium dioxide nanocomposites using PLAL technique. The antibacterial and antibiofilm activities of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were investigated against biofilm-producing strains of Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa by various methods. Our results revealed that the PLAL synthesized copper oxide-titanium dioxide nanocomposites showed enhanced anti-biofilm and antibacterial activity compared to pure titanium dioxide in a dose-dependent manner against targeted pathogens. Furthermore, the effects of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites on bacterial morphology, biofilm formation, aggregation and their colonization by targeted pathogens were also examined using scanning electron microscopy. Microscopic images clearly showed that the cell envelope of almost all the cells were rumples, rough, had irregularities and abnormal appearance with the major damage being characterized by the formation of "pits". Many depressions and indentations were also seen in their cell envelope and the original shape of Pseudomonas aeruginosa cells changed from normal rod to swollen, large and elongated which indicates the loss of membrane integrity and damage of cell wall and membrane. The findings suggested that PLAL synthesized copper oxide-titanium dioxide nanocomposites have good potential for removal of biofilm or killing of pathogenic bacteria in water distribution network and for wastewater treatment, hospital and environmental applications. In addition, cytotoxic activity of pure TiO2 and PLAL synthesized copper oxide-titanium dioxide nanocomposites against normal and healthy cells (HEK-293) and cancerous cells (HCT-116) were also evaluated by MTT assay. The MTT assay results showed no cytotoxic effects on HEK-293 cells, which suggest TiO2 and PLAL synthesized copper oxide-titanium dioxide nanocomposites are non-toxic to the normal cells.}, } @article {pmid32487374, year = {2020}, author = {Awasthi, A and Sharma, P and Jangir, L and Kamakshi, and Awasthi, G and Awasthi, KK and Awasthi, K}, title = {Dose dependent enhanced antibacterial effects and reduced biofilm activity against Bacillus subtilis in presence of ZnO nanoparticles.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {113}, number = {}, pages = {111021}, doi = {10.1016/j.msec.2020.111021}, pmid = {32487374}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacillus subtilis/*physiology ; Biofilms/*drug effects ; Gentian Violet/pharmacology ; Metal Nanoparticles/*chemistry ; Oxidative Stress/drug effects ; Reactive Oxygen Species/metabolism ; Zinc Oxide/*chemistry/toxicity ; }, abstract = {Bacterial biofilms are self-produced matrix of sticky extracellular polymeric substances. They result in fouling in the food industry, water treatment plants, and possess significant environmental and industrial impacts. Nanoparticles have shown immense potential and have been effective in combating bacterial biofilm, which is the common cause of drug resistance development, biofouling in water treatment plants and the food industry. Hence, in order to explore the same, Zinc oxide nanoparticles have been synthesized by chemical synthesis method and their action against Bacillus subtilis biofilm formation was evaluated in this study by crystal violet and ROS assay. The dose-dependent reduction in biofilm biomass and density was observed as a result of nanoparticle exposure. There was considerable reduction in biofilm formation after treatment with ZnO nanoparticles. Change in surface morphology of the Bacillus subtilis cells was observed which could be due to oxidative stress induced by ZnO nanoparticles. The oxidative stress was estimated by measurement of catalase activity that also showed dose-dependent decrease.}, } @article {pmid32486591, year = {2020}, author = {Liu, MJ and Zhang, YL and Wan, XY}, title = {[Research progress on methicillin-resistant Staphylococcus aureus biofilm].}, journal = {Zhonghua nei ke za zhi}, volume = {59}, number = {6}, pages = {473-476}, doi = {10.3760/cma.j.cn112138-20190704-00470}, pmid = {32486591}, issn = {0578-1426}, mesh = {Anti-Bacterial Agents/*therapeutic use ; *Biofilms ; Humans ; Methicillin ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Microbial Sensitivity Tests ; Staphylococcal Infections/*diagnosis/*drug therapy ; }, } @article {pmid32485913, year = {2020}, author = {Cai, H and Wang, Y and Wu, K and Guo, W}, title = {Enhanced Hydrophilic and Electrophilic Properties of Polyvinyl Chloride (PVC) Biofilm Carrier.}, journal = {Polymers}, volume = {12}, number = {6}, pages = {}, pmid = {32485913}, issn = {2073-4360}, abstract = {Polyvinyl chloride (PVC) biofilm carrier is used as a carrier for bacterial adsorption in wastewater treatment. The hydrophilicity and electrophilicity of its surface play an important role in the adsorption of bacteria. The PVC biofilm carrier was prepared by extruder, and its surface properties were investigated. In order to improve the hydrophilicity and electrophilic properties of the PVC biofilm carrier, polyvinyl alcohol (PVA) and cationic polyacrylamide (cPAM) were incorporated into polyvinyl chloride (PVC) by blending. Besides, the surface area of the PVC biofilm carrier was increased by azodicarbonamide modified with 10% by weight of zinc oxide (mAC). The surface contact angle of PVC applied by PVA and cPAM at 5 wt %, 15 wt % was 81.6°, which was 18.0% lower than pure PVC. It shows the significant improvement of the hydrophilicity of PVC. The zeta potential of pure PVC was -9.59 mV, while the modified PVC was 14.6 mV, which proves that the surface charge of PVC changed from negative to positive. Positive charge is more conducive to the adsorption of bacteria. It is obvious from the scanning electron microscope (SEM) images that holes appeared on the surface of the PVC biofilm carrier after adding mAC, which indicates the increase of PVC surface area.}, } @article {pmid32485401, year = {2020}, author = {Xiao, B and Zou, Z and Bhandari, J and Zhang, Y and Yan, G}, title = {Exposure to diode laser (810nm) affects the bacterial adherence and biofilm formation in a E. faecalis biofilm model.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101772}, doi = {10.1016/j.pdpdt.2020.101772}, pmid = {32485401}, issn = {1873-1597}, mesh = {Biofilms ; *Enterococcus faecalis ; Lasers, Semiconductor ; *Photochemotherapy/methods ; Photosensitizing Agents ; Sodium Hypochlorite ; }, abstract = {BACKGROUND: A large number of studies have shown that diode laser can effectively kill Enterococcus faecalis (E. faecalis). However, to our knowledge there has been little information regarding high-level analysis of sterilization mechanism on E. faecalis biofilm models after laser irradiation. This study provides emphasis on the E. faecalis viability and exopolysaccharide content after laser irradiation. It also aims to examine whether diode laser affects the biofilm formation and adherence of E. faecalis biofilm at the level of gene expression.

METHODS: E. faecalis (ATCC 29,212) was inoculated for biofilm formation. After growing for 48 h, the biofilms were submitted to the following treatments, twice daily (n = 6): (i) Diode laser with energy densities as 28.7 J/cm[2]; (ii) 1% sodium hypochlorite (NaOCl) was used as a positive control; (iii) 0.9 % physiological saline (NaCl) was used as a negative control. After 120 h of biofilm growth, bactericidal activity of diode laser was evaluated by using plate count method and scanning electron microscopy (SEM). The distribution of extracellular polysaccharide was assessed by Confocal laser scanning microscopy (CLSM). Anthrone method was used to quantify the amount of water-soluble exopolysaccharide (WSE) and water-insoluble exopolysaccharides (WIE) in E. faecalis. Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to assess transcription of genes (gelE, ace and esp) related to formation and adherence of E. faecalis biofilm.

RESULTS: Compared with NaCl, diode laser significantly destabilizedE. faecalis biofilm, which showing a decrease in the number of bacteria and inhibiting the adherence of biofilm (p < 0.05). From Anthrone method and CLSM, the study found that diode laser lowered the concentration of WSE and WIE in biofilms (p < 0.05). In addition, transcription of gene gelE, ace and esp were also reduced after irradiation of diode laser (p < 0.05).

CONCLUSION: By inhibiting the synthesis of WIE and WSE, diode laser may reduce the formation of E. faecalis biofilm. The expression of specific genes (gelE, ace and esp) involved in bacterial adherence and biofilm formation were down regulated under the exposure to diode laser (810 nm), which in turn is expected to decrease the pathogenicity of E. faecalis.}, } @article {pmid32484808, year = {2020}, author = {Qin, H and Liu, Y and Cao, X and Jiang, J and Lian, W and Qiao, D and Xu, H and Cao, Y}, title = {RpoS is a pleiotropic regulator of motility, biofilm formation, exoenzymes, siderophore and prodigiosin production, and trade-off during prolonged stationary phase in Serratia marcescens.}, journal = {PloS one}, volume = {15}, number = {6}, pages = {e0232549}, pmid = {32484808}, issn = {1932-6203}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cell Membrane Permeability/physiology ; Enzymes/*metabolism ; Gene Expression Regulation ; Gene Knockdown Techniques ; Movement/physiology ; Prodigiosin/*biosynthesis ; Promoter Regions, Genetic ; Serratia marcescens/*physiology ; Siderophores/*biosynthesis ; Sigma Factor/genetics/*metabolism ; Stress, Physiological ; }, abstract = {Prodigiosin is an important secondary metabolite produced by Serratia marcescens. It can help strains resist stresses from other microorganisms and environmental factors to achieve self-preservation. Prodigiosin is also a promising secondary metabolite due to its pharmacological characteristics. However, pigmentless S. marcescens mutants always emerge after prolonged starvation, which might be a way for the bacteria to adapt to starvation conditions, but it could be a major problem in the industrial application of S. marcescens. To identify the molecular mechanisms of loss of prodigiosin production, two mutants were isolated after 16 days of prolonged incubation of wild-type (WT) S. marcescens 1912768R; one mutant (named 1912768WR) exhibited reduced production of prodigiosin, and a second mutant (named 1912768W) was totally defective. Comparative genomic analysis revealed that the two mutants had either mutations or deletions in rpoS. Knockout of rpoS in S. marcescens 1912768R had pleiotropic effects. Complementation of rpoS in the ΔrpoS mutant further confirmed that RpoS was a positive regulator of prodigiosin production and that its regulatory role in prodigiosin biosynthesis was opposite that in Serratia sp. ATCC 39006, which had a different type of pig cluster; further, rpoS from Serratia sp. ATCC 39006 and other strains complemented the prodigiosin defect of the ΔrpoS mutant, suggesting that the pig promoters are more important than the genes in the regulation of prodigiosin production. Deletion of rpoS strongly impaired the resistance of S. marcescens to stresses but increased membrane permeability for nutritional competence; competition assays in rich and minimum media showed that the ΔrpoS mutant outcompeted its isogenic WT strain. All these data support the idea that RpoS is pleiotropic and that the loss of prodigiosin biosynthesis in S. marcescens 1912768R during prolonged incubation is due to a mutation in rpoS, which appears to be a self-preservation and nutritional competence (SPANC) trade-off.}, } @article {pmid32484655, year = {2020}, author = {Zhang, J and Chen, C and Chen, J and Zhou, S and Zhao, Y and Xu, M and Xu, H}, title = {Dual Mode of Anti-Biofilm Action of G3 against Streptococcus mutans.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {25}, pages = {27866-27875}, doi = {10.1021/acsami.0c00771}, pmid = {32484655}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Streptococcus mutans/*drug effects ; }, abstract = {Oral biofilms, formed by multiple microorganisms and their extracellular polymeric substances, seriously affect people's life. The emergence of the resistance of biofilms to conventional antibiotics and their side effects on the oral cavity have posed a great challenge in the treatment of dental diseases. Recently, antimicrobial peptides have been recognized as promising alternatives to conventional antibiotics due to their broad antibacterial spectrum, high antibacterial activity, and specific mechanism. However, the research of their anti-biofilm behaviors is still in its infancy, and the underlying mechanism remains unclear. In this study, we investigated the anti-biofilm activities of a designed helical peptide (G3) against Streptococcus mutans (S. mutans), one of the primary causative pathogens of caries. The results indicated that G3 inhibited S. mutans biofilm formation by interfering with different stages of biofilm development. At the initial stage, G3 inhibited the bacterial adhesion by decreasing the bacterial surface charges, hydrophobicity, membrane integrity, and adhesion-related gene transcription. At the later stage, G3 interacted with extracellular DNA to destabilize the 3D architecture of mature biofilms and thus dispersed them. The high activity of G3 against S. mutans biofilms, along with its specific modes of action, endows it great application potential in preventing and treating dental plaque diseases.}, } @article {pmid32484105, year = {2021}, author = {Al Marjania, MF and Kouhsari, E and Ali, FS and Authman, SH}, title = {Evaluation of type II Toxin-Antitoxin Systems, Antibiotic Resistance Profiles, and Biofilm Quorum Sensing Genes in Acinetobacter Baumannii Isolates in Iraq.}, journal = {Infectious disorders drug targets}, volume = {21}, number = {2}, pages = {180-186}, doi = {10.2174/1871526520666200525170318}, pmid = {32484105}, issn = {2212-3989}, mesh = {Acinetobacter Infections ; *Acinetobacter baumannii/drug effects ; Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Cross Infection ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Iraq ; Quorum Sensing/drug effects ; *Toxin-Antitoxin Systems ; }, abstract = {BACKGROUND: Bacterial Toxin-Antitoxin (TAs) systems are extensive two-component elements in the bacterial genome, which are involved in many key biological functions, including growth arrest, survival, biofilm formation, plasmid maintenance, defense against phages, persistence, and virulence.

AIM: This study aimed to assess the molecular determinants involved in TAs, biofilm quorum sensing, and antibiotic resistance profiles in Acinetobacter baumannii isolated from Baghdad's hospitals in Iraq.

METHODS: A total of 127 A. baumannii isolates were collected from 2160 different clinical samples. The antimicrobial susceptibility test was performed using the disk diffusion test. All isolates were characterized for molecular determinants involved in TAs and biofilm formation using the wellknown PCR-based sequencing assay.

RESULTS: A high multi-drug resistant (MDR) (96.06%; 122/127) and imipenem resistance (84.25%; 107/127) rates were observed from A.baumannii isolates. Results showed the presence of rhlIR gene in three isolates (2.36%), and lasIR gene appeared in two isolates (1.57%) isolates, whilst, mazEF, ccdAB, and relBE genes have not been detected among any of the isolates.

CONCLUSION: A high MDR and imipenem resistance rates within a low prevalence of rhlIR, and lasIR genes could be found in clinical A. baumannii isolates from some of the Iraqi hospitals.}, } @article {pmid32482721, year = {2020}, author = {Labine, M and DePledge, L and Feirer, N and Greenwich, J and Fuqua, C and Allen, KD}, title = {Enzymatic and Mutational Analysis of the PruA Pteridine Reductase Required for Pterin-Dependent Control of Biofilm Formation in Agrobacterium tumefaciens.}, journal = {Journal of bacteriology}, volume = {202}, number = {16}, pages = {}, pmid = {32482721}, issn = {1098-5530}, support = {R01 GM120337/GM/NIGMS NIH HHS/United States ; }, abstract = {Pterins are ubiquitous biomolecules with diverse functions including roles as cofactors, pigments, and redox mediators. Recently, a novel pterin-dependent signaling pathway that controls biofilm formation was identified in the plant pathogen, Agrobacterium tumefaciens A key player in this pathway is a pteridine reductase termed PruA, where its enzymatic activity has been shown to control surface attachment and limit biofilm formation. Here, we biochemically characterize PruA to investigate the catalytic properties and substrate specificity of this pteridine reductase. PruA demonstrates maximal catalytic efficiency with dihydrobiopterin and comparable activities with the stereoisomers dihydromonapterin and dihydroneopterin. Since A. tumefaciens does not synthesize or utilize biopterins, the likely physiological substrate is dihydromonapterin or dihydroneopterin, or both. Notably, PruA does not exhibit pteridine reductase activity with dihydrofolate or fully oxidized pterins. Site-directed mutagenesis studies of a conserved tyrosine residue, the key component of a putative catalytic triad, indicate that this tyrosine is not directly involved in PruA catalysis but may be important for substrate or cofactor binding. Additionally, mutagenesis of the arginine residue in the N-terminal TGX3RXG motif significantly reduces the catalytic efficiency of PruA, supporting its proposed role in pterin binding and catalysis. Finally, we report the enzymatic characterization of PruA homologs from Pseudomonas aeruginosa and Brucella abortus, thus expanding the roles and potential significance of pteridine reductases in diverse bacteria.Importance Biofilms are complex multicellular communities that are formed by diverse bacteria. In the plant pathogen, Agrobacterium tumefaciens, the transition from a free-living motile state to a non-motile biofilm state is governed by a novel signaling pathway involving small molecules called pterins. The involvement of pterins in biofilm formation is unexpected and prompts many questions about the molecular details of this pathway. This work biochemically characterizes the PruA pteridine reductase involved in the signaling pathway to reveal its enzymatic properties and substrate preference, thus providing important insight into pterin biosynthesis and its role in A. tumefaciens biofilm control. Additionally, the enzymatic characteristics of related pteridine reductases from mammalian pathogens are examined to uncover potential roles of these enzymes in other bacteria.}, } @article {pmid32482286, year = {2020}, author = {Fiamengo, TE and Runcan, EE and Premanandan, C and Blawut, B and Coutinho da Silva, MA}, title = {Evaluation of Biofilm Production by Escherichia coli Isolated From Clinical Cases of Canine Pyometra.}, journal = {Topics in companion animal medicine}, volume = {39}, number = {}, pages = {100429}, doi = {10.1016/j.tcam.2020.100429}, pmid = {32482286}, issn = {1946-9837}, mesh = {Animals ; Biofilms ; Dog Diseases/*microbiology ; Dogs ; Escherichia coli/*isolation & purification/metabolism ; Female ; Pyometra/microbiology/*veterinary ; }, abstract = {Many Escherichia coli (E. coli) strains produce biofilm that confers antimicrobial resistance. However, studies of biofilm production by E. coli from canine pyometra are lacking. Objectives were to elucidate the role of biofilm production by E. coli in pyometra by: (1) assessing the ability of E. coli to produce biofilm in vitro, and (2) confirming biofilm in situ. Endometrial biopsies were obtained from bitches with pyometra and preserved for microscopic analysis (n = 25). An endometrial swab was submitted for aerobic culture. Samples with confirmed E. coli were evaluated further for biofilm production in vitro and in vivo. Seventy percent of cases (16/23) resulted in pure growth of 1 or 2 E. coli strains, totaling 20 isolates. Fifteen isolates (15/20, 75%) had higher optical densities then negative controls (P < .05). On histopathology, all tissues exhibited endometrial inflammation and mucus was located within endometrial glands and occasionally overlying epithelium on 14 slides (14/16, 88%). Bacteria was noted in 50% of slides (8/16). During FISH acellular debris within the uterine lumen consistent with biofilm was noted on 94% of samples (15/16) and E coli was positively identified on all samples (15/15). Areas suggestive of the presence of biofilm were observed on all samples on scanning electron microscopy; but, bacteria consistent with E. coli were only visualized in 9 samples (9/16, 56%). In conclusion, we demonstrated that relevant strains of E. coli produce biofilm in vitro and in vivo, which may be considered in the development of new pyometra treatments aimed at disrupting these E. coli biofilm.}, } @article {pmid32479963, year = {2020}, author = {Liu, C and Yan, B and Duan, J and Hou, B}, title = {Biofilm inhibition effect of an ivermectin/silyl acrylate copolymer coating and the colonization dynamics.}, journal = {The Science of the total environment}, volume = {736}, number = {}, pages = {139599}, doi = {10.1016/j.scitotenv.2020.139599}, pmid = {32479963}, issn = {1879-1026}, mesh = {Acrylates ; Biofilms ; *Biofouling ; Ivermectin ; Polymers ; }, abstract = {Ivermectin is now being used as a substitute for toxic organic biocide in marine antifouling coatings due to its environmentally friendly nature and the efficacy against parasites. However, the release performance of ivermectin from the hydrolyzed acrylic-based resin into the seawater is not clear. Moreover, the efficiency and mechanism of ivermectin in preventing biofilm or slime formation have not been fully investigated. In this study, a coating was developed by mixing ivermectin with an acrylic-based resin, silyl acrylate copolymer, and a 45-day in situ antifouling test was conducted in the Yellow Sea. Direct observation and confocal microscope investigation indicated that the polymer coating with ivermectin was effective against biofilm formation. High-throughput sequencing analysis showed that ivermectin can selectively inhibit the adhesion of microorganisms. Abundances of Gammaproteobacteria and Alphaproteobacteria decreased significantly with the increased concentration of ivermectin. As for the eukaryote community, species of Stolidobranchia and unidentified_Bacillariophyceae were proved to be sensitive to ivermectin. Therefore, the ivermectin/silyl acrylate copolymer coating is a promising substitute for marine antifouling material.}, } @article {pmid32479710, year = {2020}, author = {Jeronimo, LP and Choi, MR and Yeon, SH and Park, SK and Yoon, YH and Choi, SH and Kim, HJ and Jang, IT and Park, JK and Rha, KS and Kim, YM}, title = {Effects of povidone-iodine composite on the elimination of bacterial biofilm.}, journal = {International forum of allergy & rhinology}, volume = {10}, number = {7}, pages = {884-892}, doi = {10.1002/alr.22568}, pmid = {32479710}, issn = {2042-6984}, mesh = {Animals ; *Anti-Infective Agents, Local ; Biofilms ; Mice ; Povidone-Iodine ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {BACKGROUND: Povidone-iodine (PVP-I) is well known as an antiseptic and exhibits extensive activity against various pathogens. However, due to its uniquely unpleasant nature, it cannot be used locally to deactivate various sinonasal pathogens. Therefore, we developed a PVP-I composite that blocks the unpleasant odor of PVP-I for use as a local antiseptic in the sinonasal cavity and evaluated its effect on bacterial biofilm's formation and elimination in in vivo and in vitro models.

METHODS: MTT, lactate dehydrogenase, and live/dead staining assay were performed to examine the cellular toxicity of PVP-I composites on the primary human nasal epithelial and RPMI 2650 cells. Crystal violet assay was performed to quantify bacterial biofilm after treating with various agents, including PVP-I and antibiotics. Hematoxylin-and-eosin staining, live/dead staining assay, and scanning electron microscopy were conducted to evaluate the effect of PVP-I on biofilm formation in a mice biofilm model.

RESULTS: It was observed that the PVP-I composite did not have any significant toxic effect on the nasal epithelial cells. Furthermore, the PVP-I composite effectively inhibited the formation of bacterial biomass within a dose-dependent manner after 48 hours of incubation with Pseudomonas aeruginosa and Staphylococcus aureus. In mice, it effectively eliminated biofilm from the mucosa of the nasal cavity and maxillary sinus at the tested concentrations.

CONCLUSION: The results of this study indicate that the PVP-I composite is a promising compound that could be used locally to prevent the formation of biofilms and to eliminate them from the sinonasal cavity.}, } @article {pmid32479611, year = {2020}, author = {Shakerimoghaddam, A and Razavi, D and Rahvar, F and Khurshid, M and Ostadkelayeh, SM and Esmaeili, SA and Khaledi, A and Eshraghi, M}, title = {Evaluate the Effect of Zinc Oxide and Silver Nanoparticles on Biofilm and icaA Gene Expression in Methicillin-Resistant Staphylococcus aureus Isolated From Burn Wound Infection.}, journal = {Journal of burn care & research : official publication of the American Burn Association}, volume = {41}, number = {6}, pages = {1253-1259}, doi = {10.1093/jbcr/iraa085}, pmid = {32479611}, issn = {1559-0488}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Burns/*microbiology ; Gene Expression/drug effects ; Metal Nanoparticles ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Silver/*pharmacology ; Staphylococcal Infections/*drug therapy ; Wound Infection/*drug therapy/*microbiology ; Zinc Oxide/*pharmacology ; }, abstract = {Methicillin-resistant Staphylococcus aureus is the cause of nosocomial and community-acquired infections. This study aimed to evaluate the effect of zinc oxide and silver nanoparticles (ZnO-Ag NPs) on biofilms formation and icaA gene expression in methicillin-resistant S. aureus (MRSA). In this study, three standard strains (ATCC 43300, 25923, and 29913) and a clinical isolate are included. The minimum inhibitory concentration (MIC) of nanoparticles was determined by microdilution broth method. The antibacterial effects of ZnO-Ag NPs either alone or in combination with each other were compared with vancomycin (as the control group). The effect of MIC and sub-MIC concentrations of ZnO-Ag NPs on biofilm formation was determined by the microtiter plate method. The expression level of the icaA gene was assessed by real-time PCR LightCycler® 96 software (Version 1.1.0.1320, Roche, Germany). technique. All experiments were repeated three times. Data were analyzed using SPSS software through ANOVA and t-test. The P-value of less than .05 was considered as statistically significant. The average MICs of ZnO, Ag, and ZnO-Ag NPs compounds were 393.2, 179.8, and 60.8 μg/ml, respectively. The compound of ZnO-Ag NPs had a synergistic effect against all isolates. ZnO-Ag NPs decreased the biofilm formation rate at MIC and sub-MIC concentrations (P < .001). Sub-MIC ZnO-Ag NPs concentration significantly reduced the icaA gene expression in S. aureus strains (P < .03). The sub-MIC concentration of ZnO-Ag NPs reduced biofilm formation rate and icaA gene expression in Staphylococcus aureus strains compared with vancomycin. It can be used to cover medical devices after examining more clinical isolates to prevent bacterial colonization.}, } @article {pmid32479089, year = {2020}, author = {Nguyen, BVG and Nagakubo, T and Toyofuku, M and Nomura, N and Utada, AS}, title = {Synergy between Sophorolipid Biosurfactant and SDS Increases the Efficiency of P. aeruginosa Biofilm Disruption.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {36}, number = {23}, pages = {6411-6420}, doi = {10.1021/acs.langmuir.0c00643}, pmid = {32479089}, issn = {1520-5827}, mesh = {*Biofilms ; Glycolipids/toxicity ; Oleic Acids ; *Pseudomonas aeruginosa ; }, abstract = {Biofilms are communities of bacteria encased in self-secreted extracellular polymeric substances (EPS) that adhere stubbornly to submerged surfaces. Once established, these communities can cause serious chronic illnesses in medical settings, while they can promote corrosion and biofouling in industrial settings. Due to the difficulty of their removal, strongly oxidizing chemicals and detergents can be used to degrade and remove biofilms by killing the cells and degrading the matrix; however, the choice of compounds is limited in delicate environments due to the potential damage they may cause. In the case of detergents, most are synthesized from nonrenewable petrochemicals that have a degree of aquatic toxicity. There is a growing need to identify and characterize alternatives to synthetic surfactants. Biosurfactants, which are surfactants produced by microorganisms, are a promising alternative since they can be synthesized from renewable resources, have low environmental toxicity, and have been shown to have higher degrees of specificity in the mechanism of action. Sophorolipids are a class of glycolipid surfactants produced by yeast that have demonstrated great promise due to large yields from renewable feedstocks and for antimicrobial properties; however, the effect of the application of sophorolipids to Gram-negative bacterial biofilms has not been well studied. We investigate the antibiofilm properties of sophorolipids by demonstrating its ability to cause the catastrophic disruption of Pseudomonas aeruginosa PAO1 biofilms in microfluidic channels. We show that while sophorolipids inflict little damage to the bacteria, they weaken the EPS biofilm matrix, leading to surface-detachment and breakup of the biofilm. Furthermore, we find that sophorolipids act cooperatively with the widely used surfactant, sodium dodecyl sulfate. When combined, concentrations ∼100-fold lower than the minimum effective concentration, when used independently, recover potency. Biosurfactants are typically expensive to produce, thus our work demonstrates a means to improve efficacy while simultaneously reducing both cost and the amount of environmentally harmful substances used.}, } @article {pmid32477314, year = {2020}, author = {Qu, Y and Li, Y and Cameron, DR and Easton, CD and Zhu, X and Zhu, M and Salwiczek, M and Muir, BW and Thissen, H and Daley, A and Forsythe, JS and Peleg, AY and Lithgow, T}, title = {Hyperosmotic Infusion and Oxidized Surfaces Are Essential for Biofilm Formation of Staphylococcus capitis From the Neonatal Intensive Care Unit.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {920}, pmid = {32477314}, issn = {1664-302X}, abstract = {Staphylococcus capitis is an opportunistic pathogen often implicated in bloodstream infections in the neonatal intensive care unit (NICU). This is assisted by its ability to form biofilms on indwelling central venous catheters (CVC), which are highly resistant to antibiotics and the immune system. We sought to understand the fundamentals of biofilm formation by S. capitis in the NICU, using seventeen clinical isolates including the endemic NRCS-A clone and assessing nine commercial and two modified polystyrene surfaces. S. capitis clinical isolates from the NICU initiated biofilm formation only in response to hyperosmotic conditions, followed by a developmental progression driven by icaADBC expression to establish mature biofilms, with polysaccharide being their major extracellular polymer substance (EPS) matrix component. Physicochemical features of the biomaterial surface, and in particular the level of the element oxygen present on the surface, significantly influenced biofilm development of S. capitis. A lack of highly oxidized carbon species on the surface prevented the immobilization of S. capitis EPS and the formation of mature biofilms. This information provides guidance in regard to the preparation of hyperosmolar total parenteral nutrition and the engineering of CVC surfaces that can minimize the risk of catheter-related bloodstream infections caused by S. capitis in the NICU.}, } @article {pmid32477292, year = {2020}, author = {Adnan, M and Patel, M and Deshpande, S and Alreshidi, M and Siddiqui, AJ and Reddy, MN and Emira, N and De Feo, V}, title = {Effect of Adiantum philippense Extract on Biofilm Formation, Adhesion With Its Antibacterial Activities Against Foodborne Pathogens, and Characterization of Bioactive Metabolites: An in vitro-in silico Approach.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {823}, pmid = {32477292}, issn = {1664-302X}, abstract = {Adiantum philippense (A. philippense), an ethnomedicinally important fern, has become an interesting herb in the search for novel bioactive metabolites, which can also be used as therapeutic agents. Primarily, in this study, A. philippense crude extract was screened for its phytochemical constituents, antagonistic potential, and effect on bacterial adhesion and biofilm formation against common food pathogens. Phytochemical profiling of A. philippense was carried out by using High Resolution-Liquid Chromatography and Mass Spectroscopy (HR-LCMS) followed by antibacterial activity via agar cup/well diffusion, broth microdilution susceptibility methods, and growth curve analysis. Antibiofilm potency and efficacy were assessed on the development, formation, and texture of biofilms through light microscopy, fluorescent microscopy, scanning electron microscopy, and the assessment of exopolysaccharide production. Correspondingly, a checkerboard test was performed to evaluate the combinatorial effect of A. philippense and chloramphenicol. Lastly, molecular docking studies of identified phytochemicals with adhesin proteins of tested food pathogens, which helps the bacteria in surface attachment and leads to biofilm formation, were assessed. A. philippense crude extract was found to be active against all tested food pathogens, displaying the rapid time-dependent kinetics of bacterial killing. A. philippense crude extract also impedes the biofilm matrix by reducing the total content of exopolysaccharide, and, likewise, the microscopic images revealed a great extent of disruption in the architecture of biofilms. A synergy was observed between A. philippense crude extract and chloramphenicol for E. coli, S. aureus, and P. aeruginosa, whereas an additive effect was observed for S. flexneri. Various bioactive phytochemicals were categorized from A. philippense crude extract using HR-LCMS. The molecular docking of these identified phytochemicals was interrelated with the active site residues of adhesin proteins, IcsA, Sortase A, OprD, EspA, and FimH from S. flexneri, S. aureus, P. aeruginosa, and E. coli, respectively. Thus, our findings represent the bioactivity and potency of A. philippense crude extract against food pathogens not only in their planktonic forms but also against/in biofilms for the first time. We have also correlated these findings with the possible mechanism of biofilm inhibition via targeting adhesin proteins, which could be explored further to design new bioactive compounds against biofilm producing foodborne bacterial pathogens.}, } @article {pmid32477285, year = {2020}, author = {Su, T and He, J and Li, N and Liu, S and Xu, S and Gu, L}, title = {A Rational Designed PslG With Normal Biofilm Hydrolysis and Enhanced Resistance to Trypsin-Like Protease Digestion.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {760}, pmid = {32477285}, issn = {1664-302X}, abstract = {A glycosyl hydrolase produced by Pseudomonas aeruginosa, PslG, has become a promising candidate for biofilm treatment because of its ability to inhibit and disperse biofilms by disrupting exopolysaccharide matrix at nanomolar concentrations. However, as a protein, PslG used for treatment may be degraded by the ubiquitous proteases (of which trypsin-like serine proteases are a major group) secreted by human cells. This would lead to an insufficient effective concentration of PslG. Here, based on the result of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and structural analysis, we generate a PslG mutant (K286A/K433S) with greatly enhanced trypsin resistance. This measure raises IC50 (the concentration of trypsin that can degrade 50% of protein in 30 min at 37°C) from 0.028 mg mL[-1] of the wild-type PslG to 0.283 mg mL[-1] of PslG [K286A/K433S] . In addition, biofilm inhibition assay shows that PslG [K286A/K433S] is much more efficient than wild-type PslG in the presence of trypsin. This indicates that PslG [K286A/K433S] is a better biofilm inhibitor than wild-type PslG in clinical use where trypsin-like proteases widely exist.}, } @article {pmid32477284, year = {2020}, author = {Priya, A and Pandian, SK}, title = {Piperine Impedes Biofilm Formation and Hyphal Morphogenesis of Candida albicans.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {756}, pmid = {32477284}, issn = {1664-302X}, abstract = {Candida albicans is the primary etiological agent associated with the pathogenesis of candidiasis. Unrestricted growth of C. albicans in the oral cavity may lead to oral candidiasis, which can progress to systemic infections in worst scenarios. Biofilm of C. albicans encompasses yeast and hyphal forms, where hyphal formation and yeast to hyphal morphological transitions are contemplated as the key virulence elements. Current clinical repercussions necessitate the identification of therapeutic agent that can limit the biofilm formation and escalating the susceptibility of C. albicans to immune system and conventional antifungals. In the present study, a plant-derived alkaloid molecule, piperine, was investigated for the antibiofilm and antihyphal activities against C. albicans. Piperine demonstrated a concentration-dependent antibiofilm activity without exerting negative impact on growth and metabolic activity. Inhibition in the hyphal development was witnessed through confocal laser-scanning microscopy and scanning electron microscopy. Interestingly, piperine displayed a tremendous potential to inhibit the virulence-associated colony morphologies, such as filamentation and wrinkling. Furthermore, piperine regulated morphological transitions between yeast and hyphal forms by inhibiting hyphal extension and swapping hyphal phase to yeast forms yet under filamentation-inducing circumstances. Remarkably, piperine-challenged C. albicans exhibited low potential for spontaneous antibiofilm resistance development. In addition, piperine effectively reduced in vivo colonization and prolonged survival of C. albicans-infected Caenorhabditis elegans, thereby expounding the distinct antivirulent potential. Transcriptomic analysis revealed piperine significantly downregulating the expression of several biofilm related and hyphal-specific genes (ALS3, HWP1, EFG1, CPH1, etc.). Furthermore, no acute toxicity was observed in the HBECs and nematodes exposed to piperine. Altogether, results from this study reveals the potential of piperine to inhibit biofilm and hyphal morphogenesis, and its in vivo efficacy and innocuous nature to HBECs suggests that piperine may be considered as a potential candidate for the treatment of biofilm-associated C. albicans infection, especially for oral candidiasis.}, } @article {pmid32476070, year = {2020}, author = {Jeon, DM and An, JS and Lim, BS and Ahn, SJ}, title = {Orthodontic bonding procedures significantly influence biofilm composition.}, journal = {Progress in orthodontics}, volume = {21}, number = {1}, pages = {14}, pmid = {32476070}, issn = {2196-1042}, support = {2017R1A2B4001834//National Research Foundation of Korea/ ; }, mesh = {Animals ; Bacterial Adhesion ; *Biofilms ; Cattle ; Porphyromonas gingivalis ; *Streptococcus mutans ; Surface Properties ; }, abstract = {BACKGROUND: Because changes in surface properties affect bacterial adhesion, orthodontic bonding procedures may significantly influence biofilm formation and composition around orthodontic appliances. However, most studies used a mono-species biofilm model under static conditions, which does not simulate the intraoral environment and complex interactions of oral microflora because the oral cavity is a diverse and changeable environment. In this study, a multi-species biofilm model was used under dynamic culture conditions to assess the effects of the orthodontic bonding procedure on biofilm formation and compositional changes in two main oral pathogens, Streptococcus mutans and Porphyromonas gingivalis.

METHODS: Four specimens were prepared with bovine incisors and bonding adhesive: untreated enamel surface (BI), enamel surface etched with 37% phosphoric acid (ET), primed enamel surface after etching (PR), and adhesive surface (AD). Surface roughness (SR), surface wettability (SW), and surface texture were evaluated. A multi-species biofilm was developed on each surface and adhesion amounts of Streptococcus mutans, Porphyromonas gingivalis, and total bacteria were analyzed at day 1 and day 4 using real-time polymerase chain reaction. After determining the differences in biofilm formation, SR, and SW between the four surfaces, relationships between bacteria levels and surface properties were analyzed.

RESULTS: The order of SR was AD < PR < BI < ET, as BI and ET showed more irregular surface texture than PR and AD. For SW, ET had the greatest value followed by PR, BI, and AD. S. mutans and P. gingivalis showed greater adhesion to BI and ET with rougher and more wettable surfaces than to AD with smoother and less wettable surfaces. The adhesion of total bacteria and S. mutans significantly increased over time, but the amount of P. gingivalis decreased. The adhesion amounts of all bacteria were positively correlated with SR and SW, irrespective of incubation time.

CONCLUSIONS: Within the limitations of this study, changes in SR and SW associated with orthodontic bonding had significant effects on biofilm formation and composition of S. mutans and P. gingivalis.}, } @article {pmid32474673, year = {2021}, author = {Liang, J and Liang, D and Liang, Y and He, J and Zuo, S and Zhao, W}, title = {Effects of a derivative of reutericin 6 and gassericin A on the biofilm of Streptococcus mutans in vitro and caries prevention in vivo.}, journal = {Odontology}, volume = {109}, number = {1}, pages = {53-66}, pmid = {32474673}, issn = {1618-1255}, support = {2018B030311047//Guangdong Science and Technology Department/ ; 201804010419//Guangzhou Science, Technology and Innovation Commission/ ; }, mesh = {Bacteriocins ; Biofilms ; Cariostatic Agents ; *Dental Caries/prevention & control ; Humans ; *Streptococcus mutans ; }, abstract = {It is known that Streptococcus mutans (S. mutans) is the leading cariogenic pathogen. Recently, an increasing number of antimicrobial peptides (AMPs) have been brought into consideration as anti-caries agents. Here, we designed and synthesized an AMP derived from reutericin 6 and/or gassericin A, named LN-7, and explored its effect on biofilm of S. mutans UA159 in vitro and development of dental caries in vivo. Antibacterial assays showed that LN-7 was more active against S. mutans (3.2 μM) than many peptide-based agents, capable of killing other types of Streptococci in oral cavity. In addition, LN-7 presented fast killing kinetics, with more than 97% S. mutans killed within 5 min. The mechanism of the antimicrobial activity mainly lies on the disruption of bacterial membrane. Effects of LN-7 on the biofilm formation and the viability of preformed biofilm were quantified by crystal violet staining, which showed that LN-7 could effectively inhibit the biofilm accumulation of S. mutans. Moreover, the biofilm of S. mutans treated with LN-7 displayed notable changes in bacterial viability and morphology, observed by confocal laser scanning microscopy and scanning electron microscopy. In addition, topical oral treatment with LN-7 could suppress the development of dental caries in vivo, reducing the occurrence of severe dental lesion in a rodent model. These results reveal a new peptide-based agent as a topical treatment for dental caries, opening the door to clinical studies to explore its potential for caries prevention.}, } @article {pmid32474537, year = {2020}, author = {Eroshenko, DV and Polyudova, TV and Pyankova, AA}, title = {VapBC and MazEF toxin/antitoxin systems in the regulation of biofilm formation and antibiotic tolerance in nontuberculous mycobacteria.}, journal = {International journal of mycobacteriology}, volume = {9}, number = {2}, pages = {156-166}, doi = {10.4103/ijmy.ijmy_61_20}, pmid = {32474537}, issn = {2212-554X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Bacterial Toxins/*genetics ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Mycobacterium smegmatis/drug effects/*genetics/*physiology ; Toxin-Antitoxin Systems/*genetics ; }, abstract = {BACKGROUND: Mycobacterium smegmatis and other nontuberculous mycobacteria (NTM) are widely distributed in the environment, but a significant increase of NTM infections has taken place in the last few decades. The objective of this study was to determine the role of toxin-antitoxin (TA) vapBC and mazEF systems that act as effectors of persistence in the stress response of NTM.

METHODS: The growth ability and the biofilm formation of NTM were evaluated by conventional methods. Bacterial cell viability was determined using MTT staining, agar plating, or the method of limiting dilutions. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of antibiotics were estimated using broth and agar dilution methods.

RESULTS: Despite a comparable growth dynamics and biofilm formation on solid/liquid interface with the wild type, a M. smegmatis vapBC, mazEF, and vapBC × mazEF deletion mutant produced more abundant pellicle and were more susceptible to heat shock. Significant differences were also found in the resistance wild type of NTM to isoniazid and ciprofloxacin reflected by higher MBC/MIC ratios. The proposed method of cultivation of agar blocks without visible growth after MIC determination into a liquid medium allows us to detect transition of all wild type of NTM strains to a dormant state in the presence of subMICs of isoniazid and ciprofloxacin while all deletion mutants failed to form dormant cells.

CONCLUSION: Our data suggest that both vapBC and mazEF TA systems putatively involved in the heat and antibiotic stress response of NTM via their key role in transition to the dormant state.}, } @article {pmid32474228, year = {2020}, author = {Wagner, EM and Pracser, N and Thalguter, S and Fischel, K and Rammer, N and Pospíšilová, L and Alispahic, M and Wagner, M and Rychli, K}, title = {Identification of biofilm hotspots in a meat processing environment: Detection of spoilage bacteria in multi-species biofilms.}, journal = {International journal of food microbiology}, volume = {328}, number = {}, pages = {108668}, doi = {10.1016/j.ijfoodmicro.2020.108668}, pmid = {32474228}, issn = {1879-3460}, mesh = {Animals ; Austria ; Biofilms/classification/growth & development ; Brochothrix/*isolation & purification ; Cattle ; Disinfection/methods ; *Food Handling ; Food Microbiology ; Foodborne Diseases/microbiology ; Meat/*microbiology ; Poultry/microbiology ; Pseudomonas/*isolation & purification ; Psychrobacter/*isolation & purification ; RNA, Ribosomal, 16S/analysis ; }, abstract = {Biofilms are comprised of microorganisms embedded in a self-produced matrix that normally adhere to a surface. In the food processing environment they are suggested to be a source of contamination leading to food spoilage or the transmission of food-borne pathogens. To date, research has mainly focused on the presence of (biofilm-forming) bacteria within food processing environments, without measuring the associated biofilm matrix components. Here, we assessed the presence of biofilms within a meat processing environment, processing pork, poultry and beef, by the detection of microorganisms and at least two biofilm matrix components. Sampling included 47 food contact surfaces and 61 non-food contact surfaces from eleven rooms within an Austrian meat processing plant, either during operation or after cleaning and disinfection. The 108 samples were analysed for the presence of microorganisms by cultivation and targeted quantitative real-time PCR based on 16S rRNA. Furthermore, the presence of the major matrix components carbohydrates, extracellular DNA and proteins was evaluated. Overall, we identified ten biofilm hotspots, among them seven of which were sampled during operation and three after cleaning and disinfection. Five biofilms were detected on food contact surfaces (cutters and associated equipment and a screw conveyor) and five on non-food contact surfaces (drains and water hoses) resulting in 9.3 % of the sites being classified as biofilm positive. From these biofilm positive samples, we cultivated bacteria of 29 different genera. The most prevalent bacteria belonged to the genera Brochothrix (present in 80 % of biofilms), Pseudomonas and Psychrobacter (isolated from 70 % biofilms). From each biofilm we isolated bacteria from four to twelve different genera, indicating the presence of multi-species biofilms. This work ultimately determined the presence of multi-species biofilms within the meat processing environment, thereby identifying various sources of potential contamination. Especially the identification of biofilms in water hoses and associated parts highlights the need of a frequent monitoring at these sites. The knowledge gained about the presence and composition of biofilms (i.e. chemical and microbiological) will help to prevent and reduce biofilm formation within food processing environments.}, } @article {pmid32474216, year = {2020}, author = {Wang, J and Liu, Q and Dong, D and Hu, H and Wu, B and Ren, H}, title = {In-situ monitoring of the unstable bacterial adhesion process during wastewater biofilm formation: A comprehensive study.}, journal = {Environment international}, volume = {140}, number = {}, pages = {105722}, doi = {10.1016/j.envint.2020.105722}, pmid = {32474216}, issn = {1873-6750}, mesh = {Actinobacteria ; *Bacterial Adhesion ; Biofilms ; Sphingomonas ; *Wastewater ; }, abstract = {The initial bacterial adhesion phase is a pivotal and unstable step in the formation of biofilms. The initiation of biofilm formation is an unstable process caused by the reversible adhesion of bacteria, which is always time-consuming and yet to be elucidated. In this study, impedance-based real time cell analysis (RTCA) was employed to comprehensively investigate the initial bacterial adhesion process. Results showed that the time required for the unstable adhesion process was significantly (p < 0.05) reduced by increasing the initial concentration of bacteria, which is mainly attributed to the large deposition rate of bacteria at high concentrations. In addition, the unstable adhesion process is also regulated by shear stress, derived in this work from orbital shaking. Shear stress improves the reversibility of unstable bacterial attachment. Furthermore, attachment characteristics during the unstable phase vary between different species of bacteria (Sphingomonas rubra, Nakamurella multipartita and mixed bacteria). The S. rubra strain and mixed culture were more prone to adhere to the substratum surface during the unstable process, which was attributed to the smaller xDLVO energy barrier and motility of species in comparison with N. multipartita. Meanwhile, the molecular composition of extracellular polymeric substances (EPS) in the initial attachment phase presented a significant difference in expressed proteins, indicating the important role of proteins in EPS that strengthen bacterial adhesion. Overall, these findings suggest that during the biofilm reactor start-up process, seed sludge conditions, including the bacterial concentration, composition and hydraulics, need to be carefully considered.}, } @article {pmid32474215, year = {2020}, author = {Huyan, J and Tian, Z and Zhang, Y and Zhang, H and Shi, Y and Gillings, MR and Yang, M}, title = {Dynamics of class 1 integrons in aerobic biofilm reactors spiked with antibiotics.}, journal = {Environment international}, volume = {140}, number = {}, pages = {105816}, doi = {10.1016/j.envint.2020.105816}, pmid = {32474215}, issn = {1873-6750}, mesh = {*Anti-Bacterial Agents/pharmacology ; Bacteria ; Biofilms ; Drug Resistance, Microbial/genetics ; *Integrons/genetics ; }, abstract = {Class 1 integrons are strongly associated with the dissemination of antibiotic resistance in bacteria. However, little is known about whether the presence of antibiotics affects the abundance of integrons and antibiotic resistance genes during biological wastewater treatment. To explore the roles of class 1 integrons in spreading antibiotic resistance genes in environmental compartments, the dynamics of integrons were followed in biofilm reactors treating synthetic wastewater respectively spiked with streptomycin (STM) and oxytetracycline (OTC). The relative abundance of the integron-integrase gene (intI1) increased 12 or 29-fold respectively when treated with STM or OTC, under incrementally increasing dosage regimes from 0 to 50 mg L[-1]. Significant increases in intI1 abundance initially occurred at an antibiotic dose of 0.1 mg L[-1]. At the beginning of the experiment, 51% to 64% of integrons carried no gene cassettes. In STM and OTC spiked systems, there was a significant increase in the proportion of integrons that contained resistance gene cassettes, particularly at intermediate and higher antibiotic concentrations. Gene cassettes encoding resistance to aminoglycosides, trimethoprim, beta-lactam, erythromycin, and quaternary ammonium compounds were all detected in the treated systems. Three tetracycline resistance genes (tetA, tetC, tetG) were significantly correlated with the abundance of intI1 (p < 0.01), despite no tet resistance being present as a gene cassette. Genome sequencing of isolates showed synteny between the tet resistance genes and intI1, mediated through linkage to transposable elements including Tn3, IS26 and ISCR3. Class 1 integrons appeared to be under positive selection in the presence of antibiotics, and might have actively acquired new gene cassettes during the experiment.}, } @article {pmid32474211, year = {2020}, author = {Zhang, Z and Liu, Y and Lu, M and Lyu, X and Gong, T and Tang, B and Wang, L and Zeng, J and Li, Y}, title = {Rhodiola rosea extract inhibits the biofilm formation and the expression of virulence genes of cariogenic oral pathogen Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {116}, number = {}, pages = {104762}, doi = {10.1016/j.archoralbio.2020.104762}, pmid = {32474211}, issn = {1879-1506}, mesh = {*Biofilms/drug effects ; *Dental Caries/drug therapy/prevention & control ; Humans ; Plant Extracts/pharmacology ; *Rhodiola ; Streptococcus mutans/genetics ; Virulence ; }, abstract = {OBJECTIVE: The present study aimed to evaluate the effect of Rhodiola rosea extract (RE) on Streptococcus mutans biofilm formation and the relevant mechanism of its action.

METHODS: The effect of RE on the biofilm formation and extracellular polysaccharides (EPS) synthesis of S. mutans was assessed by confocal laser scanning microscopy (CLSM), crystal violet staining and CFU counting method. Scanning electron microscopy (SEM) was applied to observe the surface morphology of S. mutans biofilms formed on glass coverslips and dental enamel. To study the relevant mechanism, quantitative real time PCR (qRT-PCR) and zymogram assay were applied to measure the expression of virulence genes and the enzymatic activity of glucosyltransferases (Gtfs) under the treatment of RE. The CCK-8 assay was also performed on macrophages (RAWs) and human oral keratinocytes (HOKs) in order to evaluate its biocompatibility.

RESULTS: As a result, RE inhibited the biofilm formation and EPS synthesis of S. mutans. RE also suppressed the expression of gtf genes and quorum sensing (QS) system as well as the enzymatic activity of Gtf proteins. Moreover, RE exhibited a good biocompatibility to human cells.

CONCLUSIONS: This study provides the evidence for RE as a novel anti-biofilm agent for clinical use.}, } @article {pmid32473427, year = {2020}, author = {Xiong, F and Zhao, X and Wen, D and Li, Q}, title = {Effects of N-acyl-homoserine lactones-based quorum sensing on biofilm formation, sludge characteristics, and bacterial community during the start-up of bioaugmented reactors.}, journal = {The Science of the total environment}, volume = {735}, number = {}, pages = {139449}, doi = {10.1016/j.scitotenv.2020.139449}, pmid = {32473427}, issn = {1879-1026}, mesh = {*Acyl-Butyrolactones ; Bacteria ; Biofilms ; *Quorum Sensing ; Sewage ; }, abstract = {Bioaugmentation is an effective technology for treating wastewater containing recalcitrant organic pollutants. However, it is restricted by several technical problems, including the difficult colonization and survival of the inoculated bacteria, and the time-consuming start-up process. Considering the important roles of quorum sensing (QS) in regulating microbial behaviors, this study investigated the effects of N-acyl-homoserine lactones (AHLs)-based manipulation on the start-up of biofilm reactors bioaugmented with a pyridine-degrading strain Paracoccus sp. BW001. The results showed that, in the presence of two specific exogenous AHLs (C6-HSL and 3OC6-HSL), the biofilm formation process on carriers was significantly accelerated, producing thick and structured biofilms. The protein and polysaccharide contents of the extracellular polymeric substances (EPS) and soluble microbial products (SMP) in sludge were also elevated, possibly due to the increased abundance of several EPS-producing bacterial genera. Specifically, the stability and complexity of protein structures were improved. Besides the reactor running time, the AHL-manipulation was proved to be the main factor that drove the shift of bacterial community structures in the reactors. The addition of exogenous AHLs significantly increased the succession rate of bacterial communities and decreased the bacterial alpha diversity. Most importantly, the final proportions of the inoculated strain BW001 were elevated by nearly 100% in both sludge and biofilm communities via the AHL-manipulation. These findings strongly elucidated that AHL-based QS was deeply involved in biofilm formation, sludge characteristics, and microbial community construction in bioaugmented reactors, providing a promising start-up strategy for bioaugmentation technology.}, } @article {pmid32471277, year = {2020}, author = {Gieroba, B and Krysa, M and Wojtowicz, K and Wiater, A and Pleszczyńska, M and Tomczyk, M and Sroka-Bartnicka, A}, title = {The FT-IR and Raman Spectroscopies as Tools for Biofilm Characterization Created by Cariogenic Streptococci.}, journal = {International journal of molecular sciences}, volume = {21}, number = {11}, pages = {}, pmid = {32471277}, issn = {1422-0067}, support = {LIDER/11/0070/L-8/16/NCBR/2017//National Centre for Research and Development within the Lider VIII/ ; LIDER/11/0070/L-8/16/NCBR/2017//Foundation for Polish Science/ ; }, mesh = {Bacterial Proteins/chemistry ; *Biofilms ; Dental Caries/*microbiology ; Extracellular Matrix/chemistry ; Humans ; Polysaccharides, Bacterial/chemistry ; Saliva/chemistry/microbiology ; Spectroscopy, Fourier Transform Infrared/*methods ; Spectrum Analysis, Raman/*methods ; Streptococcus/metabolism/*pathogenicity ; }, abstract = {Fourier transform infrared (FT-IR) and Raman spectroscopy and mapping were applied to the analysis of biofilms produced by bacteria of the genus Streptococcus. Bacterial biofilm, also called dental plaque, is the main cause of periodontal disease and tooth decay. It consists of a complex microbial community embedded in an extracellular matrix composed of highly hydrated extracellular polymeric substances and is a combination of salivary and bacterial proteins, lipids, polysaccharides, nucleic acids, and inorganic ions. This study confirms the value of Raman and FT-IR spectroscopies in biology, medicine, and pharmacy as effective tools for bacterial product characterization.}, } @article {pmid32471210, year = {2020}, author = {Bossù, M and Selan, L and Artini, M and Relucenti, M and Familiari, G and Papa, R and Vrenna, G and Spigaglia, P and Barbanti, F and Salucci, A and Giorgio, GD and Rau, JV and Polimeni, A}, title = {Characterization of Scardovia wiggsiae Biofilm by Original Scanning Electron Microscopy Protocol.}, journal = {Microorganisms}, volume = {8}, number = {6}, pages = {}, pmid = {32471210}, issn = {2076-2607}, abstract = {Early childhood caries (ECC) is a severe manifestation of carious pathology with rapid and disruptive progression. The ECC microbiota includes a wide variety of bacterial species, among which is an anaerobic newly named species, Scardovia wiggsiae, a previously unidentified Bifidobacterium. Our aim was to provide the first ultrastructural characterization of S. wiggsiae and its biofilm by scanning electron microscopy (SEM) using a protocol that faithfully preserved the biofilm architecture and allowed an investigation at very high magnifications (order of nanometers) and with the appropriate resolution. To accomplish this task, we analyzed Streptococcus mutans' biofilm by conventional SEM and VP-SEM protocols, in addition, we developed an original procedure, named OsO4-RR-TA-IL, which avoids dehydration, drying and sputter coating. This innovative protocol allowed high-resolution and high-magnification imaging (from 10000× to 35000×) in high-vacuum and high-voltage conditions. After comparing three methods, we chose OsO4-RR-TA-IL to investigate S. wiggsiae. It appeared as a fusiform elongated bacterium, without surface specialization, arranged in clusters and submerged in a rich biofilm matrix, which showed a well-developed micro-canalicular system. Our results provide the basis for the development of innovative strategies to quantify the effects of different treatments, in order to establish the best option to counteract ECC in pediatric patients.}, } @article {pmid32468379, year = {2020}, author = {Elsayed, MM and Elgohary, FA and Zakaria, AI and Elkenany, RM and El-Khateeb, AY}, title = {Novel eradication methods for Staphylococcus aureus biofilm in poultry farms and abattoirs using disinfectants loaded onto silver and copper nanoparticles.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {24}, pages = {30716-30728}, doi = {10.1007/s11356-020-09340-9}, pmid = {32468379}, issn = {1614-7499}, mesh = {Abattoirs ; Animals ; Biofilms ; Chickens ; Copper ; *Disinfectants ; Egypt ; Farms ; Humans ; *Metal Nanoparticles ; *Nanoparticles ; Poultry ; Staphylococcus aureus ; }, abstract = {Recent developments in the nanotechnology field have created opportunities to design new biomaterials for Staphylococcus aureus biofilm eradication. These biomaterials including disinfectant-loaded nanoparticles could overcome the limitations of conventional disinfectants. The objective of this study was to assess the biocidal activity of five commercial disinfectants (DC&R®, VirkonS®, TH4++, Tek-Trol, and peracetic acid) alone and as with silver and copper nanocomposites on S. aureus biofilm at different concentrations and exposure times. Consequently, 227 samples were collected from two broiler farms, two-layer farms, and three abattoirs at El-Dakahlia Province, Egypt, during summer 2018. The samples were collected from birds as well as the surrounding environment. S. aureus strains were isolated and biofilm producers were phenotypically evaluated by Congo red agar (CRA) test. Besides, 4 biofilm-associated genes including bap, fnbA, cna, and ebps were genotypically detected by PCR technology. Out of 227 collected samples, 141 (62.1%) strains were identified as S. aureus, while 127 strains (90.1%) were S. aureus biofilm producers for all examined samples except for hand swabs of abattoir workers. The prevalence of fnbA and bap genes was 79.5% (101/127) and 20.5% (26/127), respectively but, no strains harbored cna or ebps genes. Tested nanocomposites were prepared using an aqueous solution of metal salts such as copper sulfate and silver nitrate and added to the same amount of disinfectant solution. The obtained nanocomposites were characterized by transmission electron microscopy (TEM) and zeta potential which showed spherical and elongated particles and with a surface charge of disinfectants-silver and copper nanocomposites-of 2.92 and 3.43 mV, respectively. Complete eradication of S. aureus biofilm was observed after treatment with disinfectants loaded onto silver (AgNPs) and copper (CuNPs) nanoparticles in varying concentrations as well as at different exposure times in comparing to disinfectants alone. Our results exhibited the potential applications of disinfectant nanocomposites in complete eradication of S. aureus biofilm in farms and abattoirs without developing of disinfectant resistant bacteria.}, } @article {pmid32466464, year = {2020}, author = {Noumi, E and Merghni, A and Alreshidi, M and Del Campo, R and Adnan, M and Haddad, O and De Feo, V and Snoussi, M}, title = {Phenotypic and Genotypic Characterization with MALDI-TOF-MS Based Identification of Staphylococcus spp. Isolated from Mobile Phones with their Antibiotic Susceptibility, Biofilm Formation, and Adhesion Properties.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {11}, pages = {}, pmid = {32466464}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Cell Phone ; Drug Resistance, Bacterial ; Genotype ; Humans ; Phenotype ; Phylogeny ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; *Staphylococcus/genetics/isolation & purification ; }, abstract = {Cell phones, smartphones, and tablets are extensively used in social and professional life, so they are frequently exposed to bacteria. The main goal of the present work was to isolate and characterize Staphylococci strains from students' cell phone mobiles. Subsequently, 24 Staphylococci strains were tested against a wide range of antibiotics, for the distribution of some virulence-related genes and their ability to form biofilm. Staphylococcus spp. were cultured from all studied devices on chromogenic medium and identified using the matrix-assisted laser desorption/ionization (MALDI), time-of-flight (TOF) mass spectrometry (MS) technique (MALDI-TOF-MS). The results obtained showed that S.aureus was the dominant species (19 strains, 79.1%), followed by S.warneri (3 strains, 12.5%), and S.haemolyticus (2 strains, 8.3%). Isolated strains showed high percentages of hydrolytic enzymes production, resistance to many tested antibiotics, and 37.5% expressed the mecA gene. The tested strains were highly adhesive to polystyrene and glass and expressed implicated icaA (62.5%) and icaD (66.6%) genes. All Staphylococcus spp. strains tested were found to possess proteases and the α-hemolysin gene. Our results highlighted the importance of mobile phones as a great source of Staphylococcus spp., and these species were found to be resistant to many antibiotics with multiple antibiotic resistance (MAR) index ranging from (0.444) to (0.812). Most of the studied strains are able to form biofilm and expressed many virulence genes. Phylogenetic analysis based on the phenotypic and genetic characters highlighted the phenotypic and genetic heterogeneity of the S.aureus population studied. Further analyses are needed to elucidate the human health risks associated with the identified Staphylococci strains.}, } @article {pmid32466324, year = {2020}, author = {Abdel-Aziz, MM and Emam, TM and Raafat, MM}, title = {Hindering of Cariogenic Streptococcus mutans Biofilm by Fatty Acid Array Derived from an Endophytic Arthrographis kalrae Strain.}, journal = {Biomolecules}, volume = {10}, number = {5}, pages = {}, pmid = {32466324}, issn = {2218-273X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Ascomycota/*chemistry/pathogenicity ; Biofilms/*drug effects ; Biological Products/chemistry/*pharmacology ; Cells, Cultured ; Coriandrum/microbiology ; Endophytes/chemistry/pathogenicity ; Fatty Acids/chemistry/*pharmacology ; Fibroblasts/drug effects/microbiology ; Humans ; Streptococcus mutans/*drug effects/pathogenicity/physiology ; }, abstract = {Streptococcus mutans has been considered as the major etiological agent of dental caries, mostly due to its arsenal of virulence factors, including strong biofilm formation, exopolysaccharides production, and high acid production. Here, we present the antivirulence activity of fatty acids derived from the endophytic fungus Arthrographis kalrae isolated from Coriandrum sativum against Streptococcus mutans. The chemical composition of the fatty acids was analyzed by gas chromatography-mass spectrometry GC-MS and revealed nine compounds representing 99.6% of fatty acids, where unsaturated and saturated fatty acids formed 93.8% and 5.8 % respectively. Oleic and linoleic acids were the major unsaturated fatty acids. Noteworthy, the fatty acids at the concentration of 31.3 mg L[-1] completely inhibited Streptococcus mutans biofilm, and water insoluble extracellular polysaccharide production in both polystyrene plates, and tooth model assay using saliva-coated hydroxyapatite discs. Inhibition of biofilm correlated significantly and positively with the inhibition of water insoluble extracellular polysaccharide (R=1, p <0.0001). Furthermore, Arthrographis kalrae fatty acids at a concentration of 7.8 mg L[-1] exhibited acidogenesis-mitigation activity. They did not show bactericidal activity against Streptococcus mutans and cytotoxic activity against human oral fibroblast cells at the concentration used. On the other hand, saliva-coated hydroxyapatite discs treated with sub-minimum biofilm inhibitory concentration of fatty acids showed disturbed biofilm architecture with a few unequally distributed clumped matrices using fluorescence microscopy. Our findings revealed that the intracellular fatty acid arrays derived from endophytic Arthrographis kalrae could contribute to the biofilm-preventing alternatives, specifically Streptococcus mutans biofilms.}, } @article {pmid32466299, year = {2020}, author = {Swolana, D and Kępa, M and Idzik, D and Dziedzic, A and Kabała-Dzik, A and Wąsik, TJ and Wojtyczka, RD}, title = {The Antibacterial Effect of Silver Nanoparticles on Staphylococcus epidermidis Strains with Different Biofilm-Forming Ability.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {10}, number = {5}, pages = {}, pmid = {32466299}, issn = {2079-4991}, support = {KNW-2-K32/D/9/N//Medical University of Silesia/ ; }, abstract = {Among many infectious diseases, infections caused by pathogens of Staphylococcus species exert a substantial influence upon human health, mainly due to their continuous presence on human skin and mucous membranes. For that reason, an intensive search for new, effective anistaphyloccocal agents can currently be observed worldwide. In recent years, there has been growing interest in nanoparticles, as compounds with potential antibacterial effect. The antibacterial activity of silver containing substances has been well recognized, but thoughtful studies focused on the effect of silver nanoparticles on bacterial biofilm are scarce. The aim of this study was to assess the influence of silver nanoparticles (AgNPs) with particle sizes in the range between 10 and 100 nm, and a concentration range from 1 to 10 µg/mL, upon Staphylococcus epidermidis strains with different biofilm-forming abilities (BFAs). The studies revealed the highest level of antimicrobial activity for AgNPs in relation to S. epidermidis strains with BFA, and what is more, the observed effect was proportional to the increasing particles' size, and strains not forming biofilm were more susceptible to silver nanoparticles with the smallest examined size, which was 10 nm.}, } @article {pmid32466155, year = {2020}, author = {Staszczyk, M and Jurczak, A and Magacz, M and Kościelniak, D and Gregorczyk-Maga, I and Jamka-Kasprzyk, M and Kępisty, M and Kołodziej, I and Kukurba-Setkowicz, M and Krzyściak, W}, title = {Effect of Polyols and Selected Dental Materials on the Ability to Create a Cariogenic Biofilm-On Children Caries-Associated Streptococcus Mutans Isolates.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {10}, pages = {}, pmid = {32466155}, issn = {1660-4601}, mesh = {*Biofilms ; Child ; *Dental Caries ; Dental Materials ; Diet ; Humans ; *Polymers ; *Streptococcus mutans ; *Sweetening Agents ; }, abstract = {Secondary caries is a disease associated with the formation of biofilm on the border of the tooth and dental filling. Its development is strongly influenced by the dietary sweet foods and the type of dental material. The aim of the study was to assess the effect of sweeteners on the ability of clinical Streptococcus mutans strains to form biofilm on dental materials. Strains were isolated from plaque samples from 40 pediatric patients from the 3-6 ICADS II group. The ability to form biofilm was tested on composite and glass ionomer dental materials used for milk teeth filling in the presence of sucrose, xylitol, sorbitol, and erythritol. The bacterial film mass after 12, 24, 48, and 72 h and the number of bacterial colonies significantly decreased (p < 0.01) compared to the initial value for 5% erythritol and sorbitol on examined materials. A greater inhibitory effect was noted for glass ionomers compared to composites. Sucrose and xylitol supported biofilm formation, while erythritol had the best inhibitory effect. The use of fluoride-releasing glass ionomers exerted an effect synergistic to erythritol, i.e., inhibited plaque formation and the amount of cariogenic S. mutans. Selection of proper type of dental material together with replacing sucrose with polyols can significantly decrease risk of secondary caries development. Erithritol in combination with glass ionomer seems to be the most effective in secondary caries prevention.}, } @article {pmid32466117, year = {2020}, author = {Iseppi, R and Di Cerbo, A and Aloisi, P and Manelli, M and Pellesi, V and Provenzano, C and Camellini, S and Messi, P and Sabia, C}, title = {In Vitro Activity of Essential Oils Against Planktonic and Biofilm Cells of Extended-Spectrum β-Lactamase (ESBL)/Carbapenamase-Producing Gram-Negative Bacteria Involved in Human Nosocomial Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32466117}, issn = {2079-6382}, abstract = {The aim of this study was to analyze the antibacterial activity of four essential oils (EOs), Melaleuca alternifolia, Eucalyptus globulus, Mentha piperita, and Thymus vulgaris, in preventing the development and spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and carbapenemase (KPC)-producing Klebsiella pneumoniae. A total of 60 strains were obtained from the stock collection from the Microbiology Laboratory of Hesperia Hospital, Modena, Italy. Twenty ESBL-producing E. coli, 5 K. pneumoniae, 13 KPC-producing K. pneumoniae, and 20 MBL-producing P. aeruginosa were cultured and reconfirmed as ESBL and carbapenamase producers. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (ESBL and KPC/MBL). Antibacterial activity of the EOs was determined using the agar disk diffusion assay, and minimal inhibitory concentrations (MICs) were also evaluated. Lastly, adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 24 randomly selected strains. M. alternifolia and T. vulgaris EOs showed the best antibacterial activity against all tested strains and, as revealed by agar disk diffusion assay, M. alternifolia was the most effective, even at low concentrations. This effect was also confirmed by MICs, with values ranging from 0.5 to 16 µg/mL and from 1 to 16 µg/mL, for M. alternifolia and T. vulgaris EOs, respectively. The EOs' antibacterial activity compared to antibiotics confirmed M. alternifolia EO as the best antibacterial agent. T. vulgaris EO also showed a good antibacterial activity with MICs lower than both reference antibiotics. Lastly, a significant anti-biofilm activity was observed for the two EOs (*P < 0.05 and **P < 0.01 for M. alternifolia and T. vulgaris EOs, respectively). A good antibacterial and anti-biofilm activity of M. alternifolia and T. vulgaris EOs against all selected strains was observed, thus demonstrating a future possible use of these EOs to treat infections caused by ESBL/carbapenemase-producing strains, even in association with antibiotics.}, } @article {pmid32464310, year = {2020}, author = {Santos, FAGD and Leite-Andrade, MC and Brandão, IS and Alves, AIDS and Buonafina, MDS and Nunes, M and Araújo-Neto, LN and Freitas, MA and Brayner, FA and Alves, LC and Coutinho, HDM and Neves, RP}, title = {Anti-biofilm effect by the combined action of fluconazole and acetylsalicylic acid against species of Candida parapsilosis complex.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {84}, number = {}, pages = {104378}, doi = {10.1016/j.meegid.2020.104378}, pmid = {32464310}, issn = {1567-7257}, mesh = {Antifungal Agents/pharmacology ; Aspirin/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Candida parapsilosis/*drug effects/physiology ; Cyclooxygenase Inhibitors/pharmacology ; Fluconazole/administration & dosage/*pharmacology ; Glucose/metabolism ; Microbial Sensitivity Tests ; }, abstract = {The Candida parapsilosis complex has been associated with highly refractory infections mainly due to the presence of biofilms. High glucose levels enable the development of this virulence factor which can aggravate the clinical condition of patients with diabetes mellitus, those using parenteral nutrition, with invasive medical device, including others. Combined antifungal therapy, such as azole and cyclooxygenase inhibitors, may be an alternative in such infections since they modulate prostaglandin production favoring the adhesion and development of biofilms. Thus, the present study aimed to evaluate the influence of glucose supplementation in the formation and detection of Candida parapsilosis complex biofilms and to treat them using fluconazole and a cyclooxygenase inhibitor in combination. Protein spectra evaluation allowed the differentiation between species from the complex (score > 2) in our studies. All isolates were able to form active biofilms at different glucose concentrations. In addition, a significant reduction in biofilm formation was observed when fluconazole and acetylsalicylic acid were combined. The ultrastructural analysis presented typical biofilm characteristics by species from the complex. These data support new combined therapies for the treatment of fungal infections, especially with those which are resistant and therapeutic failure is associated with virulence factors.}, } @article {pmid32464303, year = {2020}, author = {Frassinetti, S and Falleni, A and Del Carratore, R}, title = {Effect of itraconazole on Staphylococcus aureus biofilm and extracellular vesicles formation.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104267}, doi = {10.1016/j.micpath.2020.104267}, pmid = {32464303}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Extracellular Vesicles ; Itraconazole/pharmacology ; *Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {Staphylococcus aureus is a leading cause of a wide range of clinical chronic infections mainly due to the establishment of a biofilm. Biofilm, a population of bacteria within a self-produced matrix of extracellular polymeric substance, decreases the susceptibility to antibiotics, immune defenses and contributes to antimicrobial resistance. To date antibiotic combination has been considered a strategy to combat S. aureus infection, but this approach does not solves the main pharmacokinetic problem caused by biofilms, consisting in insufficient drug penetration within the structure. Therefore, new antimicrobial agents that could overcome this resistance need to be discovered. Fighting staphylococcal resistance and biofilm formation is an important goal of the pharmaceutical research. Some fungicide has been observed to have antibacterial effect. anyway their use as antibiotics on S.aureus has been poorly studied. The aim of this work was to investigate the effect of the fungicide itraconazole (IT) on S. aureus biofilm formation and explore by SEM the morphological alteration after treatment. A strong biofilm disaggregation and morphologically different extracellular vesicles (EV) production were observed starting from sublethal IT doses. This suggests that IT resistance phenomena on the part of S. aureus are more difficult to establish respect other antibiotics. The adjuvant properties of IT could be used to combat bacterial biofilm and/or to improve antibiotic treatment. Moreover, because the production of EV represents a secretory pathway involved in intercellular communication shared to mammalian cells, fungi, and bacteria, our study is important to increase information that can be generalized to higher organisms.}, } @article {pmid32464301, year = {2020}, author = {Okaro, U and George, S and Valdes, S and Macaluso, K and Anderson, B}, title = {A non-coding RNA controls transcription of a gene encoding a DNA binding protein that modulates biofilm development in Bartonella henselae.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104272}, doi = {10.1016/j.micpath.2020.104272}, pmid = {32464301}, issn = {1096-1208}, mesh = {Adhesins, Bacterial ; Animals ; *Bartonella henselae/genetics ; Biofilms ; DNA-Binding Proteins ; RNA, Untranslated ; }, abstract = {Bartonella henselae (Bh) is a Gram-negative zoonotic bacterium that can grow as large aggregates and form biofilms in vitro dependent upon the adhesin BadA. Previously, we reported that the Houston-1 strain of Bh has a family of nine small, highly-expressed intergenic transcripts called Bartonellaregulatory transcripts, Brt1-9. Each of the Brts bears a stem and loop structure on the 3' end followed by a gene encoding a DNA binding protein called the Transcriptional regulatory proteins, Trp1-9. RNA-seq analysis of laboratory-grown bacteria revealed the trps were poorly transcribed suggesting that the 3' stem and loop on the Brts results in transcript termination upstream of the trp genes under these conditions. Here we demonstrate that transcription of brt1 continues into trp1 when Bh is grown in a biofilm. Deletion of brt1, or just the 3' terminus of brt1 (containing the stem and loop structure), resulted in increased transcription of both trp1 and badA and increased biofilm formation. Trp1 was shown to directly bind the putative badA promoter region as demonstrated by an electrophoretic mobility shift assay (EMSA). Our data suggest that the 3' end of brt1 responds to a stimulus generated by growth of Bh in an in vitro biofilm to allow increased trp1 transcription. We further show that transcription of trp1 increases under conditions consistent with the mammalian host but is not highly expressed in the cat flea vector until the bacterium is excreted into the flea feces. Based on these data, we hypothesize that the 3' end of Brt1 functions to control trp1 transcription and Trp1 in turn results in increased badA expression and enhanced biofilm formation.}, } @article {pmid32463353, year = {2020}, author = {Kim, HR and Shin, DS and Jang, HI and Eom, YB}, title = {Anti-biofilm and anti-virulence effects of zerumbone against Acinetobacter baumannii.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {8}, pages = {717-726}, doi = {10.1099/mic.0.000930}, pmid = {32463353}, issn = {1465-2080}, mesh = {Acinetobacter baumannii/*drug effects/pathogenicity/physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Drug Resistance, Multiple, Bacterial/drug effects/genetics ; Gene Expression/drug effects ; Locomotion/drug effects ; Microbial Sensitivity Tests ; Sesquiterpenes/*pharmacology ; Virulence/drug effects/genetics ; }, abstract = {Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen that affects patients with a compromised immune system and is becoming increasingly important as a hospital-derived infection. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of zerumbone as a novel anti-biofilm and/or anti-virulence agent against A. baumannii. The results showed that zerumbone at sub-inhibitory doses decreased biofilm formation and disrupted established A. baumannii biofilms. The zerumbone-induced decrease in biofilm formation was dose-dependent based on the results of microtitre plate biofilm assays and confocal laser scanning microscopy. In addition, our data validated the anti-virulence efficacy of zerumbone, wherein it significantly interfered with the motility of A. baumannii. To support these phenotypic results, transcriptional analysis revealed that zerumbone downregulated the expression of biofilm- and virulence-associated genes (adeA, adeB, adeC and bap) in A. baumannii. Overall, our findings suggested that zerumbone might be a promising bioactive agent for the treatment of biofilm- and virulence-related infections caused by multidrug-resistant A. baumannii.}, } @article {pmid32463024, year = {2020}, author = {Badar, W and Ullah Khan, MA}, title = {Analytical study of biosynthesised silver nanoparticles against multi-drug resistant biofilm-forming pathogens.}, journal = {IET nanobiotechnology}, volume = {14}, number = {4}, pages = {331-340}, pmid = {32463024}, issn = {1751-875X}, mesh = {A549 Cells ; *Anti-Bacterial Agents/chemistry/pharmacology ; Antineoplastic Agents/chemistry/pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Cell Survival/drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Particle Size ; *Silver/chemistry/pharmacology ; }, abstract = {The emergence of the huge number of multi-drug resistant (MDR) bacteria requires an alternative to the drugs. Silver nanoparticles (AgNPs) are a strong candidate for this due to their bactericidal properties, which can be better concluded by understanding their morphology and chemistry. The study hypothesised that AgNPs synthesised using leaves of Syzygium cumini can be used to treat locally emerging MDRs forming biofilms on indwelling medical devices. Synthesised particles were characterised by methods like UV-visible spectroscopy, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Zetasizer. Fourier transform infrared spectroscopy, and high-performance liquid chromatography were used to predict phytochemicals present in the leaves. The shape of particles is revealed to be relatively spherical, with average size to be around 10-100 nm. Phenolic compounds are attributed to the formation of nanoparticles, stability analysis shows particles to be stable, and zeta potential determined the surface charge to be -20.1 mV. Biosynthesised particles are found to possess efficient antibacterial activity MDR bacteria developing biofilms in medical devices; hence, it is concluded that S. cumini based NPs can be used to develop a layer on implant-related medical devices. Toxicity evaluation against A594 cancer cells portrays AgNPs to be potential tumour reduction agents in a concentration-dependent manner.}, } @article {pmid32462243, year = {2020}, author = {Cusimano, MG and Ardizzone, F and Nasillo, G and Gallo, M and Sfriso, A and Martino-Chillura, D and Schillaci, D and Baldi, F and Gallo, G}, title = {Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag[+] release as determined by a novel phycoerythrin-based assay.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {14}, pages = {6325-6336}, pmid = {32462243}, issn = {1432-0614}, support = {none//Università di Palermo/ ; none//Università Ca' Foscari di Venezia/ ; }, mesh = {Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Culture Media/chemistry ; Iron/analysis/*chemistry/metabolism ; Klebsiella oxytoca/metabolism ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Phycoerythrin/chemistry ; Polysaccharides, Bacterial/chemistry/metabolism ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry/metabolism/pharmacology ; Staphylococcus aureus/drug effects ; }, abstract = {Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag[+], Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium-containing citrate (as sole carbon source) and supplemented with Ag[+] and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag[+] ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence-based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium-dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag[+] release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents.Key points • Klebsiella oxytoca DSM 29614 produces bimetal nanoparticles containing Fe and Ag.• Fe concentration in growth medium affects nanoparticle yield and composition.• Phycoerythrin fluorescence-based assay was developed to determine Ag[+]release.• Antimicrobial efficacy of bimetal nanoparticle parallels Ag[+]ions release.}, } @article {pmid32462094, year = {2020}, author = {Lima, JY and Moreira, C and Nunes Freitas, PN and Olchanheski, LR and Veiga Pileggi, SA and Etto, RM and Staley, C and Sadowsky, MJ and Pileggi, M}, title = {Structuring biofilm communities living in pesticide contaminated water.}, journal = {Heliyon}, volume = {6}, number = {5}, pages = {e03996}, pmid = {32462094}, issn = {2405-8440}, abstract = {The wide use of pesticides in agriculture expose microbiota to stressful conditions that require the development of survival strategies. The bacterial response to many pollutants has not been elucidated in detail, as well as the evolutionary processes that occur to build adapted communities. The purpose of this study was to evaluate the bacterial population structure and adaptation strategies in planktonic and biofilm communities in limited environments, as tanks containing water used for washing herbicide containers. This biodiversity, with high percentage of nonculturable microorganisms, was characterized based on habitat and abiotic parameters using molecular and bioinformatics tools. According to water and wastewater standards, the physicochemical conditions of the tank water were inadequate for survival of the identified bacteria, which had to develop survival strategies in this hostile environment. The biodiversity decreased in the transition from planktonic to biofilm samples, indicating a possible association between genetic drift and selection of individuals that survive under stressful conditions, such as heating in water and the presence of chlorine, fluorine and agrochemicals over a six-month period. The abundance of Enterobacter, Acinetobacter and Pseudomonas in biofilms from water tanks was linked to essential processes, deduced from the genes attributed to these taxonomic units, and related to biofilm formation, structure and membrane transport, quorum sensing and xenobiotic degradation. These characteristics were randomly combined and fixed in the biofilm community. Thus, communities of biofilm bacteria obtained under these environmental conditions serve as interesting models for studying herbicide biodegradation kinetics and the prospects of consortia suitable for use in bioremediation in reservoirs containing herbicide-contaminated wastewater, as biofilters containing biofilm communities capable of degrading herbicides.}, } @article {pmid32460495, year = {2020}, author = {Zhang, J and Brown, J and Scurr, DJ and Bullen, A and MacLellan-Gibson, K and Williams, P and Alexander, MR and Hardie, KR and Gilmore, IS and Rakowska, PD}, title = {Cryo-OrbiSIMS for 3D Molecular Imaging of a Bacterial Biofilm in Its Native State.}, journal = {Analytical chemistry}, volume = {92}, number = {13}, pages = {9008-9015}, doi = {10.1021/acs.analchem.0c01125}, pmid = {32460495}, issn = {1520-6882}, mesh = {Adenine/chemistry ; *Biofilms ; Freezing ; Imaging, Three-Dimensional ; Microscopy, Confocal ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing ; Spectrometry, Mass, Secondary Ion/*methods ; }, abstract = {Secondary ion mass spectrometry (SIMS) is gaining popularity for molecular imaging in the life sciences because it is label-free and allows imaging in two and three dimensions. The recent introduction of the OrbiSIMS has significantly improved the utility for biological imaging through combining subcellular spatial resolution with high-performance Orbitrap mass spectrometry. SIMS instruments operate in high-vacuum, and samples are typically analyzed in a freeze-dried state. Consequently, the molecular and structural information may not be well-preserved. We report a method for molecular imaging of biological materials, preserved in a native state, by using an OrbiSIMS instrument equipped with cryogenic sample handling and a high-pressure freezing protocol compatible with mass spectrometry. The performance is demonstrated by imaging a challenging sample (>90% water) of a mature Pseudomonas aeruginosa biofilm in its native state. The 3D distribution of quorum sensing signaling molecules, nucleobases, and bacterial membrane molecules is revealed with high spatial-resolution and high mass-resolution. We discover that analysis in the frozen-hydrated state yields a 10 000-fold increase in signal intensity for polar molecules such as amino acids, which has important implications for SIMS imaging of metabolites and pharmaceuticals.}, } @article {pmid32460269, year = {2020}, author = {Hillman, KM and Sims, RC}, title = {Struvite formation associated with the microalgae biofilm matrix of a rotating algal biofilm reactor (RABR) during nutrient removal from municipal wastewater.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {4}, pages = {644-655}, doi = {10.2166/wst.2020.133}, pmid = {32460269}, issn = {0273-1223}, mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; *Microalgae ; Nutrients ; Phosphates ; Phosphorus ; Struvite ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Struvite was observed within the microalgae biofilm matrix of an outdoor, pilot-scale rotating algal biofilm reactor (RABR) designed to remove nitrogen and phosphorus from municipal anaerobic digester filtrate. The bottom layer of cells (2.5-month growth) and two top layers of cells (1-week and 2.5-month growth) were evaluated on east- and west-facing sides of the RABR. Sun orientation and shading effects of upper biofilm layers impacted the species composition and microalgae content of the bottom biofilm layers. Struvite formed within the microalgae biofilm matrix, and a higher struvite content appeared to be correlated with a higher microalgae content. The highest struvite content (expressed as %wt. of total solids) was observed in the east- and west-facing bottom layers of growth and west-facing 1-week growth (5.0%, 4.3%, and 4.1%, respectively). The lowest struvite content was observed in east- and west-facing 2.5-month growth and east-facing 1-week growth (1.1%, 1.5%, and 1.1%, respectively). Despite RABR influent component ion molar ratios with potential for various magnesium and calcium precipitates, microalgae biofilm provided pH and nucleation sites favorable to struvite precipitation. This evaluation is the first in the refereed literature the authors are aware of that reports on the association of struvite formation in the presence of a microalgae biofilm.}, } @article {pmid32459613, year = {2020}, author = {Badal, D and Jayarani, AV and Kollaran, MA and Kumar, A and Singh, V}, title = {Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems.}, journal = {Journal of medical microbiology}, volume = {69}, number = {6}, pages = {906-919}, doi = {10.1099/jmm.0.001199}, pmid = {32459613}, issn = {1473-5644}, mesh = {4-Butyrolactone/analogs & derivatives/physiology ; Bacterial Proteins/*physiology ; *Biofilms ; Equipment Contamination ; Fimbriae, Bacterial/physiology ; Flagella/physiology ; Intubation, Intratracheal/*instrumentation ; Pneumonia, Ventilator-Associated/etiology ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing ; }, abstract = {Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.}, } @article {pmid32457749, year = {2020}, author = {Parducho, KR and Beadell, B and Ybarra, TK and Bush, M and Escalera, E and Trejos, AT and Chieng, A and Mendez, M and Anderson, C and Park, H and Wang, Y and Lu, W and Porter, E}, title = {The Antimicrobial Peptide Human Beta-Defensin 2 Inhibits Biofilm Production of Pseudomonas aeruginosa Without Compromising Metabolic Activity.}, journal = {Frontiers in immunology}, volume = {11}, number = {}, pages = {805}, pmid = {32457749}, issn = {1664-3224}, support = {R25 GM061331/GM/NIGMS NIH HHS/United States ; SC1 GM096916/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Cells, Cultured ; Humans ; Metabolic Networks and Pathways/*drug effects ; Microbial Viability/*drug effects ; Microscopy, Atomic Force ; Organic Chemicals/metabolism ; Pseudomonas aeruginosa/*drug effects/*metabolism ; Quorum Sensing ; Signal Transduction ; beta-Defensins/*pharmacology ; }, abstract = {Biofilm production is a key virulence factor that facilitates bacterial colonization on host surfaces and is regulated by complex pathways, including quorum sensing, that also control pigment production, among others. To limit colonization, epithelial cells, as part of the first line of defense, utilize a variety of antimicrobial peptides (AMPs) including defensins. Pore formation is the best investigated mechanism for the bactericidal activity of AMPs. Considering the induction of human beta-defensin 2 (HBD2) secretion to the epithelial surface in response to bacteria and the importance of biofilm in microbial infection, we hypothesized that HBD2 has biofilm inhibitory activity. We assessed the viability and biofilm formation of a pyorubin-producing Pseudomonas aeruginosa strain in the presence and absence of HBD2 in comparison to the highly bactericidal HBD3. At nanomolar concentrations, HBD2 - independent of its chiral state - significantly reduced biofilm formation but not metabolic activity, unlike HBD3, which reduced biofilm and metabolic activity to the same degree. A similar discrepancy between biofilm inhibition and maintenance of metabolic activity was also observed in HBD2 treated Acinetobacter baumannii, another Gram-negative bacterium. There was no evidence for HBD2 interference with the regulation of biofilm production. The expression of biofilm-related genes and the extracellular accumulation of pyorubin pigment, another quorum sensing controlled product, did not differ significantly between HBD2 treated and control bacteria, and in silico modeling did not support direct binding of HBD2 to quorum sensing molecules. However, alterations in the outer membrane protein profile accompanied by surface topology changes, documented by atomic force microscopy, was observed after HBD2 treatment. This suggests that HBD2 induces structural changes that interfere with the transport of biofilm precursors into the extracellular space. Taken together, these data support a novel mechanism of biofilm inhibition by nanomolar concentrations of HBD2 that is independent of biofilm regulatory pathways.}, } @article {pmid32457724, year = {2020}, author = {Aqawi, M and Gallily, R and Sionov, RV and Zaks, B and Friedman, M and Steinberg, D}, title = {Cannabigerol Prevents Quorum Sensing and Biofilm Formation of Vibrio harveyi.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {858}, pmid = {32457724}, issn = {1664-302X}, abstract = {Cannabigerol (CBG) is a non-psychoactive cannabinoid naturally present in trace amounts in the Cannabis plant. So far, CBG has been shown to exert diverse activities in eukaryotes. However, much less is known about its effects on prokaryotes. In this study, we investigated the potential role of CBG as an anti-biofilm and anti-quorum sensing agent against Vibrio harveyi. Quorum sensing (QS) is a cell-to-cell communication system among bacteria that involves small signaling molecules called autoinducers, enabling bacteria to sense the surrounding environment. The autoinducers cause alterations in gene expression and induce bioluminescence, pigment production, motility and biofilm formation. The effect of CBG was tested on V. harveyi grown under planktonic and biofilm conditions. CBG reduced the QS-regulated bioluminescence and biofilm formation of V. harveyi at concentrations not affecting the planktonic bacterial growth. CBG also reduced the motility of V. harveyi in a dose-dependent manner. We further observed that CBG increased LuxO expression and activity, with a concomitant 80% downregulation of the LuxR gene. Exogenous addition of autoinducers could not overcome the QS-inhibitory effect of CBG, suggesting that CBG interferes with the transmission of the autoinducer signals. In conclusion, our study shows that CBG is a potential anti-biofilm agent via inhibition of the QS cascade.}, } @article {pmid32457717, year = {2020}, author = {Silva, AV and Edel, M and Gescher, J and Paquete, CM}, title = {Exploring the Effects of bolA in Biofilm Formation and Current Generation by Shewanella oneidensis MR-1.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {815}, pmid = {32457717}, issn = {1664-302X}, abstract = {Microbial electrochemical technologies (METs) have emerged in recent years as a promising alternative green source of energy, with microbes consuming organic matter to produce energy or valuable byproducts. It is the ability of performing extracellular electron transfer that allows these microbes to exchange electrons with an electrode in these systems. The low levels of current achieved have been the limiting factor for the large-scale application of METs. Shewanella oneidensis MR-1 is one of the most studied electroactive organisms regarding extracellular electron transfer, and it has been shown that biofilm formation is a key factor for current generation. The transcription factor bolA has been identified as a central player in biofilm formation in other organisms, with its overexpression leading to increased biofilm. In this work we explore the effect of this gene in biofilm formation and current production by S. oneidensis MR-1. Our results demonstrate that an increased biofilm formation and consequent current generation was achieved by the overexpression of this gene. This information is crucial to optimize electroactive organisms toward their practical application in METs.}, } @article {pmid32456668, year = {2020}, author = {Akinpelu, S and Ajayi, A and Smith, SI and Adeleye, AI}, title = {Efflux pump activity, biofilm formation and antibiotic resistance profile of Klebsiella spp. isolated from clinical samples at Lagos University Teaching Hospital.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {258}, pmid = {32456668}, issn = {1756-0500}, mesh = {Amoxicillin/pharmacology ; Ampicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cefuroxime/pharmacology ; Cells, Cultured ; Community-Acquired Infections ; Drug Combinations ; *Drug Resistance, Multiple, Bacterial ; Hospitals, Teaching ; Hospitals, University ; Humans ; Imipenem/pharmacology ; Klebsiella/*drug effects/isolation & purification/metabolism/pathogenicity ; Klebsiella Infections/blood/drug therapy/urine ; Microbial Sensitivity Tests ; Nigeria ; Ofloxacin/pharmacology ; Tertiary Care Centers ; }, abstract = {OBJECTIVE: Nosocomial and community acquired multidrug resistant Klebsiella infections are wide spread resulting in high morbidity and mortality due to limited number of antibiotics treatment options. This study investigated efflux pump activity, biofilm forming potential and antibiotic susceptibility profile of Klebsiella spp. isolated from clinical samples in a tertiary hospital in Lagos Nigeria. Eighteen clinical Klebsiella spp. isolated from urine, blood and sputum were subjected to antibiotic susceptibility testing using the disc diffusion method. Efflux pump activity was evaluated by the ethidium bromide cartwheel method and biofilm forming ability was determined by the tissue culture plate technique.

RESULTS: All 18 (100%) Klebsiella isolates were resistant to cefuroxime, cefixime, amoxicillin - clavulanate, ampicillin + cloxacillin, cefotaxime, and imipenem. Seventeen (94.4%) were resistant to ofloxacin while sixteen (88.9%) were resistance to nalidixic acid, Gentamicin and levofloxacin. All Klebsiella isolates possessed active efflux pump with the ability to form biofilm. However, their biofilm forming capabilities varied as 4 (22.2%) were strong, 3 (16.7%) were moderate and 11 (61.1%) were weak biofilm formers. Findings in this study reveal multiple factors at play in mediating the high level of antibiotic resistance observed in Klebsiella isolates. Hence a multifaceted approach is advocated in managing the infections caused by the pathogen.}, } @article {pmid32455691, year = {2020}, author = {Teul, J and Deja, S and Celińska-Janowicz, K and Ząbek, A and Młynarz, P and Barć, P and Junka, A and Smutnicka, D and Bartoszewicz, M and Pałka, J and Miltyk, W}, title = {LC-QTOF-MS and [1]H NMR Metabolomics Verifies Potential Use of Greater Omentum for Klebsiella pneumoniae Biofilm Eradication in Rats.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32455691}, issn = {2076-0817}, support = {DEC-2012/07/N/NZ4/02528//National Science Centre in Poland/ ; }, abstract = {Bacterial wound infections are a common problem associated with surgical interventions. In particular, biofilm-forming bacteria are hard to eradicate, and alternative methods of treatment based on covering wounds with vascularized flaps of tissue are being developed. The greater omentum is a complex organ covering the intestines in the abdomen, which support wound recovery following surgical procedures and exhibit natural antimicrobial activity that could improve biofilm eradication. We investigated changes in rats' metabolome following Klebsiella pneumoniae infections, as well as the greater omentum's ability for Klebsiella pneumoniae biofilm eradication. Rats received either sterile implants or implants covered with Klebsiella pneumoniae biofilm (placed in the peritoneum or greater omentum). Metabolic profiles were monitored at days 0, 2, and 5 after surgery using combined proton nuclear magnetic resonance ([1]H NMR) and high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOF‑MS) measurements of urine samples followed by chemometric analysis. Obtained results indicated that grafting of the sterile implant to the greater omentum did not cause major disturbances in rats' metabolism, whereas the sterile implant located in the peritoneum triggered metabolic perturbations related to tricarboxylic acid (TCA) cycle, as well as choline, tryptophan, and hippurate metabolism. Presence of implants colonized with Klebsiella pneumoniae biofilm resulted in similar levels of metabolic perturbations in both locations. Our findings confirmed that surgical procedures utilizing the greater omentum may have a practical use in wound healing and tissue regeneration in the future.}, } @article {pmid32455536, year = {2020}, author = {Ferriol-González, C and Domingo-Calap, P}, title = {Phages for Biofilm Removal.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32455536}, issn = {2079-6382}, support = {20200063//European Society of Clinical Microbiology and Infectious Diseases/ ; 724519/ERC_/European Research Council/International ; }, abstract = {Biofilms are clusters of bacteria that live in association with surfaces. Their main characteristic is that the bacteria inside the biofilms are attached to other bacterial cells and to the surface by an extracellular polymeric matrix. Biofilms are capable of adhering to a wide variety of surfaces, both biotic and abiotic, including human tissues, medical devices, and other materials. On these surfaces, biofilms represent a major threat causing infectious diseases and economic losses. In addition, current antibiotics and common disinfectants have shown limited ability to remove biofilms adequately, and phage-based treatments are proposed as promising alternatives for biofilm eradication. This review analyzes the main advantages and challenges that phages can offer for the elimination of biofilms, as well as the most important factors to be taken into account in order to design effective phage-based treatments.}, } @article {pmid32454957, year = {2020}, author = {Sapata, DM and Ramos, AL and Sábio, S and Normando, D and Pascotto, RC}, title = {Evaluation of biofilm accumulation on and deactivation force of orthodontic Ni-Ti archwires before and after exposure to an oral medium: A prospective clinical study.}, journal = {Journal of dental research, dental clinics, dental prospects}, volume = {14}, number = {1}, pages = {41-47}, pmid = {32454957}, issn = {2008-210X}, abstract = {Background. This in vitro study aimed to evaluate biofilm accumulation on and deactivation force of orthodontic nickeltitanium (NiTi) archwires before and after exposure to an oral medium. Methods. Four commercial brands of orthodontic NiTi 0.016" archwires were examined before and after exposure to the oral medium for 4 weeks. Six archwire segments, 30 mm in length, from each manufacturer were tested in a device with four selfligating brackets, channel 0.022", adapted to a universal test machine to evaluate the deactivation force between 0.5 and 3 mm of deflection. The presence of biofilm on the archwire surfaces was evaluated by scanning electron microscopy, before and after exposure to the oral medium. The Wilcoxon and kappa tests were applied to the biofilm scores, three-way ANOVA for repeated measures (Bonferroni post-test), and linear regression between biofilm and deactivation force. Results. The exposure to the oral medium promoted moderate to severe presence of debris on the archwire surfaces and caused a reduction in deactivation force for the Ormco and GAC brands, while maintaining them with adequate force levels. The MORELLI and ORTHOMETRIC archwires underwent no significant reduction in deactivation force; moreover, these maintained elevated levels of force after exposure to the oral medium. The Spearman test indicated a low correlation between biofilm accumulation and deflection force for the Morelli (R2=0.132 and P=0.683) and Orthometric (R2=0.308 and P=0.330) brands. On the other hand, the GAC (R=0.767 and P=0.004) and ORMCO (R=0.725 and P=0.008) brands exhibited statistically significant correlation between these variables. Conclusion. Exposure to the oral medium for one month might give rise to significant changes in the dissipation of forces of orthodontic NiTi archwires, resulting from biofilm accumulation.}, } @article {pmid32454735, year = {2019}, author = {Kart, D and Kuştimur, AS}, title = {Investigation of Gelatinase Gene Expression and Growth of Enterococcus faecalis Clinical Isolates in Biofilm Models.}, journal = {Turkish journal of pharmaceutical sciences}, volume = {16}, number = {3}, pages = {356-361}, pmid = {32454735}, issn = {2148-6247}, abstract = {OBJECTIVES: Enterococcus faecalis is the major reason for biofilm-related infections and it also interacts with Staphylococcus aureus in biofilms. Gelatinase (gelE) enzyme is an important virulence factor of E. faecalis for biofilm formation. This study aimed to compare the biofilm producing E. faecalis isolates from urine and urinary catheters. The influence of S. aureus on the growth of E. faecalis biofilm cells was also investigated in a dual biofilm model in vitro. Another aim was to evaluate E. faecalis gelE gene expression during biofilm formation.

MATERIALS AND METHODS: Firstly, crystal violet staining was used to measure the total biofilm biomass of the isolates. Secondly, plate counting was performed to determine the biofilm formation ability of E. faecalis isolates and the effect of S. aureus on E. faecalis biofilm formation. Finally, the gelE expression profile of the isolates was assessed by quantitative real time-polymerase chain reaction.

RESULTS: According to crystal violet staining and plate counting, all E. faecalis isolates were biofilm producers and the number of E. faecalis sessile cells increased in the presence of S. aureus. Among the 21 E. faecalis isolates, ten expressed high levels of the gelE gene, while eight of them had low expression profiles (p<0.05).

CONCLUSION: When they grow together, S. aureus may give some advantages to E. faecalis such as increasing sessile cell growth. The expression of the gelE gene was not affected by E. faecalis biofilm formation of the isolates collected from the patients with urinary tract infections.}, } @article {pmid32454336, year = {2020}, author = {Zakaria, BS and Dhar, BR}, title = {Changes in syntrophic microbial communities, EPS matrix, and gene-expression patterns in biofilm anode in response to silver nanoparticles exposure.}, journal = {The Science of the total environment}, volume = {734}, number = {}, pages = {139395}, doi = {10.1016/j.scitotenv.2020.139395}, pmid = {32454336}, issn = {1879-1026}, mesh = {Biofilms ; Electrodes ; Extracellular Polymeric Substance Matrix ; *Metal Nanoparticles ; *Microbiota ; Silver ; }, abstract = {Understanding the toxic effect of silver nanoparticles (AgNPs) on various biological wastewater treatment systems is of significant interest to researchers. In recent years, microbial electrochemical technologies have opened up new opportunities for bioenergy and chemicals production from organic wastewater. However, the effects of AgNPs on microbial electrochemical systems are yet to be understood fully. Notably, no studies have investigated the impact of AgNPs on a microbial electrochemical system fed with a complex fermentable substrate. Here, we investigated the impact of AgNPs (50 mg/L) exposure to a biofilm anode in a microbial electrolysis cell (MEC) fed with glucose. The volumetric current density was 29 ± 2.0 A/m[3] before the AgNPs exposure, which decreased to 20 ± 2.2 A/m[3] after AgNPs exposure. The biofilms produced more extracellular polymeric substances (EPS) to cope with the AgNPs exposure, while carbohydrate to protein ratio in EPS considerably increased from 0.4 to 0.7. Scanning electron microscope (SEM) imaging also confirmed the marked excretion of EPS, forming a thick layer covering the anode biofilms after AgNPs injection. Transmission electron microscope (TEM) imaging showed that AgNPs still penetrated some microbial cells, which could explain the deterioration of MEC performance after AgNPs exposure. The relative expression level of the quorum signalling gene (LuxR) increased by 30%. Microbial community analyses suggested that various fermentative bacterial species (e.g., Bacteroides, Synergistaceae_vadinCA02, Dysgonomonas, etc.) were susceptible to AgNPs toxicity, which led to the disruption of their syntrophic partnership with electroactive bacteria. The abundance of some specific electroactive bacteria (e.g., Geobacter species) also decreased. Moreover, decreased relative expressions of various extracellular electron transfer associated genes (omcB, omcC, omcE, omcZ, omcS, and pilA) were observed. However, the members of family Enterobacteriaceae, known to perform a dual function of fermentation and anodic respiration, became dominant after biofilm anode exposed to AgNPs. Thus, EPS extraction provided partial protection against AgNPs exposure.}, } @article {pmid32454294, year = {2020}, author = {Baattrup-Pedersen, A and Graeber, D and Kallestrup, H and Guo, K and Rasmussen, JJ and Larsen, SE and Riis, T}, title = {Effects of low flow and co-occurring stressors on structural and functional characteristics of the benthic biofilm in small streams.}, journal = {The Science of the total environment}, volume = {733}, number = {}, pages = {139331}, doi = {10.1016/j.scitotenv.2020.139331}, pmid = {32454294}, issn = {1879-1026}, mesh = {Biofilms ; Chlorophyll A ; Ecosystem ; *Geologic Sediments ; *Rivers ; }, abstract = {Low flow and co-occurring stress is a more and more frequent phenomenon these years in small agricultural streams as a consequence of climate change. In the present study we explored short and longer term structural responses of the stream benthic algae community and biofilm metabolism to multiple stress in small streams applying a semi-experimental approach. We hypothesized that i) a reduction in flow in combination with secondary stress (nutrients and sediments) have immediate effects on the benthic algae community in terms of biomass (chlorophyll a, biovolume), taxonomic and trait (lifeform and size distribution) compositions as well as on metabolism (GPP and CR), and ii) that changes in the benthic algae community persist due to altered environmental settings but that functional redundancy among benthic algae species provides a high level of resilience in metabolism (GPP and CR). Overall, we found that stress imposed by nutrients was less pronounced than stress imposed by fine sediments under low flow, and that nutrient enrichment to some extent mitigated effects of fine sediments. Fine sediment deposition mediated a decline in the fraction of erect algae and/or algae with mucilage stalks but this did not happen under co-occurring stress from both sediments and nutrients. Additionally, fine sediment deposition mediated a decline in GPP of the biofilm, but again this did not happen under co-occurring stress from nutrients. We conclude that 1) the benthic algae community and biofilm metabolism displayed similar resilience to stress imposed by low flow and co-occurring stress from nutrients and sediments on a short and longer time scale and 2) as structure-function adaptations may occur at several trophic levels in the biofilm, more research is needed to explore mechanisms underlying mitigating effects of nutrients in response to sediment deposition under low flow.}, } @article {pmid32452215, year = {2022}, author = {Badi, S and Salah Abbassi, M and Snoussi, M and Werheni, R and Hammami, S and Maal-Bared, R and Hassen, A}, title = {High rates of antibiotic resistance and biofilm production in Escherichia coli isolates from food products of animal and vegetable origins in Tunisia: a real threat to human health.}, journal = {International journal of environmental health research}, volume = {32}, number = {2}, pages = {406-416}, doi = {10.1080/09603123.2020.1769039}, pmid = {32452215}, issn = {1369-1619}, mesh = {Animals ; Biofilms ; Drug Resistance, Microbial ; *Escherichia coli/genetics ; Humans ; Microbial Sensitivity Tests ; Tunisia ; *Vegetables ; }, abstract = {The aim of this study was to compare the antibiotic susceptibility of eighty Escherichia coli isolates from vegetables and food products of animal origin in Tunisia, and to study their genes encoding antibiotic resistance and in vitro biofilm forming capacity. Antimicrobial susceptibilities were determined, as well as PCR investigation of genes associated with antibiotic resistance. Biofilm formation was tested using four different methods: the microtiter plate-, MTT-staining-, XTT-staining-, and the Congo Red Agar assays. High antibiotic resistance rates were observed for amoxicillin (68.7%), amoxicillin/clavulanic acid (73.7%), gentamicin (68.7%), kanamycin (66.2%), nalidixic acid (36.2%), streptomycin (68.7%) and tetracycline (35%). The majority of isolates was multidrug resistant and biofilm producer. MTT testing showed that vegetables isolates were significantly higher biofilm producers compared to foods of animal origins. This study showed that E. coli isolates from food products were reservoirs of genes encoding antibiotic-resistance and have a high propensity to produce biofilm.}, } @article {pmid32451882, year = {2020}, author = {Li, M and Shi, D and Li, Y and Xiao, Y and Chen, M and Chen, L and Du, H and Zhang, W}, title = {Recombination of T4-like Phages and Its Activity against Pathogenic Escherichia coli in Planktonic and Biofilm Forms.}, journal = {Virologica Sinica}, volume = {35}, number = {5}, pages = {651-661}, pmid = {32451882}, issn = {1995-820X}, mesh = {*Bacteriophages ; Biofilms ; Escherichia coli ; *Phage Therapy ; Plankton ; }, abstract = {The increasing emergence of multi-drug resistant Escherichia coli (E. coli) has become a global concern, primarily due to the limitation of antimicrobial treatment options. Phage therapy has been considered as a promising alternative for treating infections caused by multi-drug resistant E. coli. However, the application of phages as a promising antimicrobial agent is limited by their narrow host range and specificity. In this research, a recombinant T4-like phage, named WGqlae, has been obtained by changing the receptor specificity determinant region of gene 37, using a homologous recombination platform of T4-like phages established by our laboratory previously. The engineered phage WGqlae can lyse four additional hosts, comparing to its parental phages WG01 and QL01. WGqlae showed similar characteristics, including thermo and pH stability, optimal multiplicity of infection and one-step growth curve, to the donor phage QL01. In addition, sequencing results showed that gene 37 of recombinant phage WGqlae had genetically stable even after 20 generations. In planktonic test, phage WGqlae had significant antimicrobial effects on E. coli DE192 and DE205B. The optical density at 600 nm (OD600) of E. coli in phage WGqlae treating group was significantly lower than that of the control group (P < 0.01). Besides, phage WGqlae demonstrated an obvious inhibitory effect on the biofilm formation and the clearance of mature biofilms. Our study suggested that engineered phages may be promising candidates for future phage therapy applications against pathogenic E. coli in planktonic and biofilm forms.}, } @article {pmid32451587, year = {2020}, author = {Vishwakarma, J and V L, S}, title = {Unraveling the anti-biofilm potential of green algal sulfated polysaccharides against Salmonella enterica and Vibrio harveyi.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {14}, pages = {6299-6314}, pmid = {32451587}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Chlamydomonas reinhardtii/chemistry ; Chlorophyta/*chemistry ; DNA, Bacterial/metabolism ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/isolation & purification/pharmacology ; Polysaccharides/chemistry/isolation & purification/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Quorum Sensing/drug effects ; Salmonella enterica/*drug effects/growth & development ; Sulfates/chemistry/isolation & purification/pharmacology ; Vibrio/*drug effects/growth & development ; }, abstract = {One of the main reasons for the bacterial resistance to antibiotics is caused by biofilm formation of microbial pathogens during bacterial infections. Salmonella enterica and Vibrio harveyi are known to form biofilms and represent a major health concern worldwide, causing human infections responsible for morbidity and mortality. The current study aims to investigate the effect of purified sulfated polysaccharides (SPs) from Chlamydomonas reinhardtii (Cr) on planktonic and biofilm growth of these bacteria. The effect of Cr-SPs on bacterial planktonic growth was assessed by using the agar well diffusion method, which showed clear zones ranging from 13 to 26 mm in diameter from 0.5 to 8 mg/mL of Cr-SPs against both the bacteria. Time-kill activity and reduction in clonogenic propagation further help to understand the anti-microbial potential of Cr-SPs. The minimum inhibitory concentration of Cr-SPs against S. enterica and V. harveyi was as low as 440 μg/mL and 490 μg/mL respectively. Cr-SPs inhibited bacterial cell attachment up to 34.65-100% at 0.5-8 mg/mL in S. enterica and V. harveyi respectively. Cr-SPs also showed 2-fold decrease in the cell surface hydrophobicity, indicating their potential to prevent bacterial adherence. Interestingly, Cr-SPs efficiently eradicated the preformed biofilms. Increased reduction in total extracellular polysaccharide (EPS) and extracellular DNA (eDNA) content in a dose-dependent manner demonstrates Cr-SPs ability to interact and destroy the bacterial EPS layer. SEM analysis showed that Cr-SPs effectively distorted preformed biofilms and also induced morphological changes. Furthermore, Cr-SPs also showed anti-quorum-sensing potential by reducing bacterial urease and protease activities. These results indicate the potential of Cr-SPs as an anti-biofilm agent and will help to develop them as alternative therapeutics against biofilm-forming bacterial infections. KEY POINTS: • Cr-SPs not only inhibited biofilm formation but also eradicated preformed biofilms. • Cr-SPs altered bacterial cell surface hydrophobicity preventing biofilm formation. • Cr-SPs efficiently degraded eDNA of the EPS layer disrupting mature biofilms. • Cr-SPs reduced activity of quorum-sensing-mediated enzymes like protease and urease.}, } @article {pmid32450528, year = {2020}, author = {Zhang, L and Liang, E and Cheng, Y and Mahmood, T and Ge, F and Zhou, K and Bao, M and Lv, L and Li, L and Yi, J and Lu, C and Tan, Y}, title = {Is combined medication with natural medicine a promising therapy for bacterial biofilm infection?.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {128}, number = {}, pages = {110184}, doi = {10.1016/j.biopha.2020.110184}, pmid = {32450528}, issn = {1950-6007}, mesh = {Anti-Bacterial Agents/adverse effects/*therapeutic use ; Bacteria/*drug effects/growth & development ; Bacterial Infections/*drug therapy/microbiology ; Bacteriophages/physiology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial ; Drug Therapy, Combination ; Humans ; Plant Preparations/adverse effects/*therapeutic use ; Quorum Sensing/drug effects ; Treatment Outcome ; }, abstract = {Bacterial biofilms widely exist in nature and seriously threaten global public health. Biofilms always cause persistent infection and seriously aggravate the occurrence of antibiotic resistance, which makes the treatment of bacterial infection difficult. Current conventional therapies, such as antibiotics, bacteriophages and quorum sensing inhibitors, are widely used to combat biofilms. However, these therapies are inadequate for the safe and effective treatment of biofilms. Antibiotics often produce resistance in treated bacteria, and antibacterial peptides are easily decomposed by proteases, so their efficacy is reduced. These results indicate that the treatment of biofilms needs further improvement. Increasing evidence has shown that natural medicine therapies have significant inhibitory effects on biofilms. This review summarized and analyzed the efficacy characteristics and corresponding mechanisms of conventional and natural medicine therapies combatting biofilms. By comparison, the advantages and disadvantages of those therapies have been classified and interpreted, so we have inferred that combined medication with natural medicines will be a more effective strategy against biofilms. This review lays a promising foundation for the development of antibiofilm agents and provides novel thinking for the treatment of bacterial biofilm infections.}, } @article {pmid32450425, year = {2020}, author = {Zhou, X and Ahmad, JI and van der Hoek, JP and Zhang, K}, title = {Thermal energy recovery from chlorinated drinking water distribution systems: Effect on chlorine and microbial water and biofilm characteristics.}, journal = {Environmental research}, volume = {187}, number = {}, pages = {109655}, doi = {10.1016/j.envres.2020.109655}, pmid = {32450425}, issn = {1096-0953}, mesh = {Biofilms ; Chlorine ; *Drinking Water ; Hot Temperature ; Water Microbiology ; Water Supply ; }, abstract = {Thermal energy recovery from drinking water has a high potential in the application of sustainable building and industrial cooling. However, drinking water and biofilm microbial qualities should be concerned because the elevated water temperature after cold recovery may influence the microbial activities in water and biofilm phases in drinking water distribution systems (DWDSs). In this study, the effect of cold recovery on microbial qualities was investigated in a chlorinated DWDS. The chlorine decay was slight (1.1%-15.5%) due to a short contact time (~60 s) and was not affected by the cold recovery (p > 0.05). The concentrations of cellular ATP and intact cell numbers in the bulk water were partially inactivated by the residual chlorine, with the removal rates of 10.1%-16.2% and 22.4%-29.4%, respectively. The chlorine inactivation was probably promoted by heat exchangers but was not further enhanced by higher temperatures. The higher water temperature (25 °C) enhanced the growth of biofilm biomass on pipelines. Principle coordination analysis (PCoA) showed that the biofilms on the stainless steel plates of HEs and the plastic pipe inner surfaces had totally different community compositions. Elevated temperatures favored the growth of Pseudomonas spp. and Legionella spp. in the biofilm after cold recovery. The community functional predictions revealed more abundances of five human diseases (e.g. Staphylococcis aureus infection) and beta-lactam resistance pathways in the biofilms at higher temperature. Compared with a previous study with a non-chlorinated DWDS, chlorine dramatically reduced the biofilm biomass growth but raised the relative abundances of the chlorine-resistant genera (i.e. Pseudomonas and Sphingomonas) in bacterial communities.}, } @article {pmid32450399, year = {2020}, author = {Tu, C and Chen, T and Zhou, Q and Liu, Y and Wei, J and Waniek, JJ and Luo, Y}, title = {Biofilm formation and its influences on the properties of microplastics as affected by exposure time and depth in the seawater.}, journal = {The Science of the total environment}, volume = {734}, number = {}, pages = {139237}, doi = {10.1016/j.scitotenv.2020.139237}, pmid = {32450399}, issn = {1879-1026}, mesh = {*Biofilms ; China ; Environmental Monitoring ; Microplastics ; Seawater ; Water Pollutants, Chemical ; }, abstract = {The effects of microbial colonization and biofilm formation on microplastics in the marine and coastal environments have aroused global concern recently. However, the simultaneous influences of exposure time and depth on biofilm formation, and subsequently on the properties variations of microplastics is less studied. In this study, polyethylene (PE) film was exposed at three depths (2 m, 6 m, and 12 m) for three time periods (30 days, 75 days, and 135 days) in the coastal seawater of Yellow Sea, China. The results show that the total amount of biofilms markedly increased with exposure time, but decreased with water depth. Typical morphologies and compositions of biofilms such as coccus-, rod-, disc-shaped bacteria and filaments, as well as a dense layer of extracellular polymeric substances were observed on the surfaces of the PE microplastics. Biofilm formation could decrease the hydrophobicity of PE microplastics, and increase the abundances of hydrophilic C-O and CO groups on the surface of PE. Alphaproteobacteria, Gammaproteobacteria and Bacteroidia were identified as the core microbiome of the PE associated biofilms, while the dominant bacteria families vary from the early to the late phases of the biofilm formation. Our results indicate that microplastics associated biofilms could affect the environmental processes and fates of microplastics in the marine and coastal environment.}, } @article {pmid32449144, year = {2020}, author = {Hujslová, M and Gryndlerová, H and Bystrianský, L and Hršelová, H and Gryndler, M}, title = {Biofilm and planktonic microbial communities in highly acidic soil (pH < 3) in the Soos National Nature Reserve, Czech Republic.}, journal = {Extremophiles : life under extreme conditions}, volume = {24}, number = {4}, pages = {577-591}, doi = {10.1007/s00792-020-01177-x}, pmid = {32449144}, issn = {1433-4909}, support = {CZ.02.1.01/0.0/0.0/16_013/0001821//Ministry of Education, Youth and Sports of the Czech Republic/ ; 17-09946S//Grantová Agentura České Republiky/ ; }, mesh = {Biofilms ; Czech Republic ; Hydrogen-Ion Concentration ; *Microbiota ; *Plankton ; Soil ; Soil Microbiology ; }, abstract = {Biofilm formation is a typical life strategy used by microorganisms populating acidic water systems. The same strategy might be used by microbes in highly acidic soils that are, however, neglected in this regard. In the present study, the microbial community in such highly acidic soil in the Soos National Nature Reserve (Czech Republic) has been investigated using high-throughput DNA sequencing and the organisms associated with biofilm life mode and those preferring planktonic life were distinguished using the biofilm trap technique. Our data show the differences between biofilm and planktonic microbiota fraction, although the majority of the organisms were capable of using both life modes. The by far most abundant prokaryotic genus was Acidiphilium and fungi were identified among the most abundant eukaryotic elements in biofilm formations. On the other hand, small flagellates from diverse taxonomical groups predominated in plankton. The application of cellulose amendment as well as the depth of sampling significantly influenced the composition of the detected microbial community.}, } @article {pmid32446309, year = {2020}, author = {Lundström, T and Lingström, P and Wattle, O and Carlén, A and Birkhed, D}, title = {Equine saliva components during mastication, and in vivo pH changes in the oral biofilm of sound and carious tooth surfaces after sucrose exposure.}, journal = {Acta veterinaria Scandinavica}, volume = {62}, number = {1}, pages = {21}, pmid = {32446309}, issn = {1751-0147}, mesh = {Animals ; Biofilms/*drug effects ; Dental Caries/*microbiology ; Horses/*physiology ; Hydrogen-Ion Concentration ; Mastication/*physiology ; Microbiota/drug effects ; Saliva/*chemistry ; Sucrose/*pharmacology ; Tooth/*microbiology ; }, abstract = {BACKGROUND: The role of saliva composition and dietary sugar in development of infundibular caries in equine cheek teeth is not fully understood. This study analysed electrolyte and urea concentrations in saliva in relation to different forage and measured pH changes after sucrose application in vivo in sound and carious cheek teeth.

RESULTS: Forage type had no effect on the equine saliva electrolyte concentrations, which varied considerably both intra- and inter-individually. Chewing resulted in increased values for all electrolytes except bicarbonate. Compared with stimulated human saliva, horse saliva after mastication, contained higher amounts of potassium, calcium and bicarbonate, and less phosphate. The in vivo pH measurements showed a lower resting pH and a more pronounced pH drop after sucrose application in carious teeth compared to sound teeth.

CONCLUSIONS: No large differences were found between the composition of equine saliva and human saliva. A more pronounced acidogenicity was found for the carious than sound teeth. Thus, the caries process in equine cheek teeth seems to follow the same pattern as in human teeth, caused by acid production by oral microorganisms after sugar consumption.}, } @article {pmid32444896, year = {2020}, author = {Yang, Z and Wang, Z and Lei, M and Zhu, J and Yang, Y and Wu, S and Yu, B and Niu, H and Ying, H and Liu, D and Wang, Y}, title = {Effects of Spo0A on Clostridium acetobutylicum with an emphasis on biofilm formation.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {6}, pages = {80}, doi = {10.1007/s11274-020-02859-6}, pmid = {32444896}, issn = {1573-0972}, support = {21706123//the National Nature Science Foundation of China/ ; 21636003//Key Programme/ ; SBK2017010373//Outstanding Youth Foundation of Jiangsu Province of China/ ; 2018YFA0902200//National Key Research and Development Program of China/ ; 2018YFB1501705//National Key Research and Development Program of China/ ; KYCX18_1111//Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; IRT_14R28//the Program for Changjiang Scholars and Innovative Research Team in University/ ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Biofuels/microbiology ; Clostridium acetobutylicum/genetics/growth & development/*metabolism ; Fermentation ; Gene Expression Profiling ; Gene Silencing ; Genetic Engineering/methods ; Transcription Factors/genetics ; }, abstract = {Clostridium acetobutylicum is a well-known strain for biofuel production. In previous work, it was found that this strain formed biofilm readily during fermentation processes. Biofilm formation could protect cells and enhance productivities under environmental stresses in our previous work. To explore the molecular mechanism of biofilm formation, Spo0A of C. acetobutylicum was selected to investigate its influences on biofilm formation and other physiological performances. When spo0A gene was disrupted, the spo0A mutant could hardly form biofilm. The aggregation and adhesion abilities of the spo0A mutant as well as its swarming motility were dramatically reduced compared to those of wild type strain. Sporulation was also negatively influenced by spo0A disruption, and solvent production was almost undetectable in the spo0A mutant fermentation. Furthermore, proteomic differences between wild type strain and the spo0A mutant were consistent with physiological performances. This is the first study confirming a genetic clue to C. acetobutylicum biofilm and will be valuable for biofilm optimization through genetic engineering in the future.}, } @article {pmid32443816, year = {2020}, author = {Khan, F and Yu, H and Kim, YM}, title = {Bactericidal Activity of Usnic Acid-Chitosan Nanoparticles against Persister Cells of Biofilm-Forming Pathogenic Bacteria.}, journal = {Marine drugs}, volume = {18}, number = {5}, pages = {}, pmid = {32443816}, issn = {1660-3397}, support = {NRF-2019R1A2C1087156//National Research Foundation of Korea/ ; R2020052//National Institute of Fisheries Science/ ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Benzofurans/chemistry/*pharmacology ; *Biofilms ; Chitosan/chemistry/*pharmacology ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Humans ; Nanoparticles ; }, abstract = {The present study aimed to prepare usnic acid (UA)-loaded chitosan (CS) nanoparticles (UA-CS NPs) and evaluate its antibacterial activity against biofilm-forming pathogenic bacteria. UA-CS NPs were prepared through simple ionic gelification of UA with CS, and further characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and field-emission transmission electron microscopy. The UA-CS NPs presented a loading capacity (LC) of 5.2%, encapsulation efficiency (EE) of 24%, and a spherical shape and rough surface. The maximum release of UA was higher in pH 1.2 buffer solution as compared to that in pH 6.8 and 7.4 buffer solution. The average size and zeta potential of the UA-CS NPs was 311.5 ± 49.9 nm in diameter and +27.3 ± 0.8 mV, respectively. The newly prepared UA-CS NPs exhibited antibacterial activity against persister cells obtained from the stationary phase in batch culture, mature biofilms, and antibiotic-induced gram-positive and gram-negative pathogenic bacteria. Exposure of sub-inhibitory concentrations of UA-CS NPs to the bacterial cells resulted in a change in morphology. The present study suggests an alternative method for the application of UA into nanoparticles. Furthermore, the anti-persister activity of UA-CS NPs may be another possible strategy for the treatment of infections caused by biofilm-forming pathogenic bacteria.}, } @article {pmid32443196, year = {2020}, author = {Sun, X and Chen, B and Xia, B and Li, Q and Zhu, L and Zhao, X and Gao, Y and Qu, K}, title = {Impact of mariculture-derived microplastics on bacterial biofilm formation and their potential threat to mariculture: A case in situ study on the Sungo Bay, China.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {262}, number = {}, pages = {114336}, doi = {10.1016/j.envpol.2020.114336}, pmid = {32443196}, issn = {1873-6424}, mesh = {Animals ; Bacteria ; Bays ; Biofilms ; China ; Environmental Monitoring ; Microplastics ; *Plastics ; Water Pollutants, Chemical/*analysis ; }, abstract = {Microplastics (MPs) pollution in the marine environment has attracted considerable global attention. However, the colonization of microorganisms on mariculture-derived MPs and their effects on mariculture remain poorly understood. In this study, the MPs (fishing nets, foams and floats) and a natural substrate, within size ranges (1-4 mm), were then incubated for 21 days in Sungo Bay (China), and the composition and diversity of bacterial communities attached on all substrates were investigated. Results showed that bacterial communities on MPs mainly originated from their surrounding seawater and sediment, with an average contribution on total MPs adherent population of 47.91% and 37.33%, respectively. Principle coordinate analysis showed that community similarity between MPs and surrounding seawater decreased with exposure time. In addition, lower average bacterial community diversity and higher relative abundances of bacteria from the genera Vibrio, Pseudoalteromonas and Alteromonas on MPs than those in their surrounding seawater and sediments indicated that MPs might enrich potential pathogens and bacteria related with carbohydrate metabolism. They are responsible for the significant differences in KEGG Orthology pathways (infectious disease and carbohydrate metabolism) between MPs and seawater. The KO pathway (Infectious Diseases) associated with MPs was also significantly higher than those with feathers in the nearshore area. MPs might be vectors for enrichment of potentially pathogenic Vibrio, and enhance the ecological risk of MPs to mariculture industry.}, } @article {pmid32442664, year = {2020}, author = {Liu, W and Lu, H and Chu, X and Lou, T and Zhang, N and Zhang, B and Chu, W}, title = {Tea polyphenols inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances resistance to Klebsiella pneumoniae infection in Caenorhabditis elegans model.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104266}, doi = {10.1016/j.micpath.2020.104266}, pmid = {32442664}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Caenorhabditis elegans ; Chromobacterium ; Klebsiella pneumoniae ; *Pneumonia ; Polyphenols/pharmacology ; Pseudomonas aeruginosa ; *Quorum Sensing ; Tea ; Virulence ; }, abstract = {Bacteria cells can communicate with each other via quorum sensing (QS) system. Various physiological characteristics including virulence factors and biofilm formation are controlled by QS. So interrupting the bacterial communication is an alternative strategy instead of antibiotics for control bacterial infection. The aim of this study was to investigate the effects of tea polyphenols (TPs) on quorum sensing and virulence factors of Klebsiella pneumoniae. In vitro study showed that the anti-QS activity of tea polyphenols against Chromobacterium violaceum in violacein production. At sub-MICs, TPs inhibited the motility, reduced protease and exopolysaccharide (EPS) production and also biofilm formation in K. pneumoniae. In addition, in vivo study showed that tea polyphenols at 200 μg/mL and 400 μg/mL increased the survival rate of Caenorhabditis elegans to 73.3% and 82.2% against K. pneumonia infection. Our findings suggest that tea polyphenols can act as an effective QS inhibitor and can serve as a novel anti-virulence agent for the management of bacterial pathogens.}, } @article {pmid32442576, year = {2020}, author = {Swiontek Brzezinska, M and Walczak, M and Kalwasińska, A and Richert, A and Świątczak, J and Deja-Sikora, E and Burkowska-But, A}, title = {Biofilm formation during biodegradation of polylactide, poly (3,4 hydroxybutyrate) and poly(ε-caprolactone) in activated sludge.}, journal = {International journal of biological macromolecules}, volume = {159}, number = {}, pages = {539-546}, doi = {10.1016/j.ijbiomac.2020.05.107}, pmid = {32442576}, issn = {1879-0003}, mesh = {Bacteria ; Biocompatible Materials/chemistry ; *Biodegradation, Environmental ; *Biofilms ; Chemical Phenomena ; Hydrolysis ; Hydroxybutyrates/*chemistry ; Polyesters/*chemistry ; Polymers/chemistry ; Sewage/*microbiology ; }, abstract = {Biodegradable materials, namely pure polylactide (PLA), poly (3,4-hydroxybutyrate) (PHB), poly(ε-caprolactone) (PCL) were investigated to assess their degradability by activated sludge. The study aimed at the isolation of biofilm-forming bacteria and the determination of their hydrolytic activity toward the PLA, PHB, and PCL with embedded PHMG derivatives. The biological oxygen demand and physical properties (tensile strength, water vapor permeability, surface structure) of materials indicated that PCL was the best biodegradable film. Aeromonas and Rhodococcus isolated from the polymers' surface during the process of decomposition showed the ability to form biofilms. The introduction of PHMG derivatives into PLA, PCL, and PHB films did not affect biofilm formation and hydrolase activity for most of the isolates. PHMG derivatives at the concentration of 1% disturbed the degradation process.}, } @article {pmid32441080, year = {2020}, author = {Arutyunov, AS and Tsareva, TV and Kirakosyan, LG and Levchenko, IM}, title = {[Features and significance of adhesion of bacteria and fungi of the oral cavity as the initial stage of the formation of a microbial biofilm on dental polymer materials].}, journal = {Stomatologiia}, volume = {99}, number = {2}, pages = {79-84}, doi = {10.17116/stomat20209902179}, pmid = {32441080}, issn = {0039-1735}, mesh = {Bacteria ; Biofilms ; Candida albicans ; *Dental Materials ; Mouth ; *Polymers ; }, abstract = {OBJECTIVE: Characteristics of the adhesion of yeast fungi and oral bacteria of various types in vitro to samples of polymeric materials for fixed structures of dental prostheses, obtained using various technologies: adjective digital 3D printing and traditional methods.

MATERIAL AND METHODS: Conducted model experiments on the adhesion of bacterial (including the main periodontopic-pathogenic species - P. gingivalis, P. intermedia, etc.) and fungal pathogens (C. albicans) to standard samples of polymer materials NextDent C & B Micro Filled Hybrid («NextDent», Netherlands), Detax Freeprint temp UV («Detax», Germany), obtained by digital additive 3D printing technology, and Luxatemp Automix Plus («DMG», Germany) and Acrytemp («Zhermack», Italy) - by the traditional method as a control. Removal of adhering microbes from the material was carried out using an ultrasound machine (exposure time 10 minutes, power 60 kHz).

RESULTS: The dependence of the degree of microbial adhesion on the nature of the material and processing technology (3D printing, milling) was established. The materials of NextDent C & B Micro Filled Hybrid and Detax Freeprint temp UV showed high resistance to adhesion of clinical isolates of periodontal pathogenic bacteria and C. albicans fungi.

CONCLUSION: The lowest adhesion values for periodontopathogenic species and C. albicans fungi were detected when using samples of materials obtained by 3D printing: NextDent C & B Micro Filled Hybrid and Detax Freeprint temp UV compared to Luxatemp Automix Plus and Acrytemp polymers.}, } @article {pmid32440423, year = {2020}, author = {Lee, M and Ponraja, G and McLeod, K and Chong, S}, title = {Breast Implant Illness: A Biofilm Hypothesis.}, journal = {Plastic and reconstructive surgery. Global open}, volume = {8}, number = {4}, pages = {e2755}, pmid = {32440423}, issn = {2169-7574}, abstract = {BACKGROUND: "Breast implant illness" (BII) is a poorly defined cluster of nonspecific symptoms, attributed by patients as being caused by their breast implants. These symptoms can include joint pain, skin and hair changes, concentration, and fatigue. Many patients complaining of BII symptoms are dismissed as psychosomatic. There are currently over 10,000 peer-reviewed articles on breast implants, but at the time of commencing this study, only 2 articles discussed this entity. At the same time, mainstream media and social media are exploding with nonscientific discussion about BII.

METHODS: We have prospectively followed 50 consecutive patients, self-referring for explantation due to BII. We analyzed their preoperative symptoms and followed up each patient with a Patient-Reported Outcome Questionnaire. All implants and capsules were, if possible, removed en bloc. Explanted implants were photographed. Implant shell and capsule sent for histology and microbiological culture.

RESULTS: BII symptoms were not shown to correlate with any particular implant type, surface, or fill. There was no significant finding as to duration of implant or location of original surgery. Chronic infection was found in 36% of cases with Propionibacterium acnes the most common finding. Histologically, synoviocyte metaplasia was found in a significantly greater incidence than a matched cohort that had no BII symptoms (P = 0.0164). Eighty-four percent of patients reported partial or complete resolution of BII symptoms on Patient-Reported Outcome Questionnaire. None of the 50 patients would consider having breast implants again.

CONCLUSION: The authors believe BII to be a genuine entity worthy of further study. We have identified microbiological and histological abnormalities in a significant number of patients identifying as having BII. A large proportion of these patients have reported resolution or improvement of their symptoms in patient-reported outcomes. Improved microbiology culture techniques may identify a larger proportion of chronic infection, and further investigation of immune phenotypes and toxicology may also be warranted in this group.}, } @article {pmid32439613, year = {2020}, author = {Toledano-Osorio, M and Osorio, R and Aguilera, FS and Medina-Castillo, AL and Toledano, M and Osorio, E and Acosta, S and Chen, R and Aparicio, C}, title = {Polymeric nanoparticles protect the resin-dentin bonded interface from cariogenic biofilm degradation.}, journal = {Acta biomaterialia}, volume = {111}, number = {}, pages = {316-326}, doi = {10.1016/j.actbio.2020.05.002}, pmid = {32439613}, issn = {1878-7568}, mesh = {Biofilms ; *Dental Bonding ; Dentin ; Dentin-Bonding Agents/pharmacology ; Materials Testing ; *Nanoparticles ; Polymers ; Resin Cements/pharmacology ; Tensile Strength ; Zinc ; }, abstract = {The objective was to assess doxycycline (Dox) and zinc (Zn) doped nanoparticles' (NPs) potential to protect the resin-dentin interface from cariogenic biofilm. Three groups of polymeric NPs were tested: unloaded, loaded with zinc and with doxycycline. NPs were applied after dentin etching. The disks were exposed to a cariogenic biofilm challenge in a Drip-Flow Reactor during 72 h and 7 d. Half of the specimens were not subjected to biofilm formation but stored 72 h and 7 d. LIVE/DEAD® viability assay, nano-dynamic mechanical assessment, Raman spectroscopy and field emission electron microscopy (FESEM) analysis were performed. The measured bacterial death rates, at 7 d were 46% for the control group, 51% for the undoped-NPs, 32% for Dox-NPs, and 87% for Zn-NPs; being total detected bacteria reduced five times in the Dox-NPs group. Zn-NPs treated samples reached, in general, the highest complex modulus values at the resin-dentin interface over time. Regarding the mineral content, Zn-NPs-treated dentin interfaces showed the highest mineralization degree associated to the phosphate peak and the relative mineral concentration. FESEM images after Zn-NPs application permitted to observe remineralization of the etched and non-resin infiltrated collagen layer, and bacteria were scarcely encountered. The combined antibacterial and remineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Dox-NPs exerted an antibacterial role but did not remineralize the bonded interface. Undoped-NPs did not improve the properties of the interfaces. Application of Zn-doped NPs during the bonding procedure is encouraged. STATEMENT OF SIGNIFICANCE: Application of Zn-doped nanoparticles on acid etched dentin reduced biofilm formation and viability at the resin-dentin interface due to both remineralization and antibacterial properties. Doxycycline-doped nanoparticles also diminished oral biofilm viability, but did not remineralize the resin-dentin interface.}, } @article {pmid32439578, year = {2020}, author = {Rocca, DM and Silvero C, MJ and Aiassa, V and Cecilia Becerra, M}, title = {Rapid and effective photodynamic treatment of biofilm infections using low doses of amoxicillin-coated gold nanoparticles.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101811}, doi = {10.1016/j.pdpdt.2020.101811}, pmid = {32439578}, issn = {1873-1597}, mesh = {Amoxicillin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Gold ; *Metal Nanoparticles ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Pseudomonas aeruginosa ; Staphylococcus aureus ; }, abstract = {Bacterial biofilm are complex microbial communities covered by a matrix of extracellular polymeric substances, which develops when a community of microorganisms irreversibly adheres to a living or inert surface. This structure is considered an important virulence factor because it is difficult to eradicate and often responsible for treatment failures. This adherent community represents one of the greatest problems in public health due to the continued emergence of conventional antibiotic-therapy resistance. Photodynamic Antimicrobial Therapy (PACT) is a therapeutic alternative and promises to be an effective treatment against multiresistant bacteria biofilm, demonstrating a broad spectrum of action. This work demonstrates the reduction in biofilms of relevant clinical isolates (as Pseudomonas aeruginosa and Staphylococcus aureus) treated with PACT using low concentrations of amoxicillin-coated gold nanoparticles (amoxi@AuNP) as a photosensitizer. Moreover, the viability reduction of 60% in S. aureus biofilms and 70% in P. aeruginosa biofilms were obtained after three hours of irradiation with white light and amoxi@AuNP. Scanning electron microscopy analysis revealed that amoxi@AuNP could penetrate and cause damage to the biofilm matrix, and interact with bacteria cells. A strong biofilm production in P. aeruginosa was observed by confocal laser scanning microscopy using acridine orange as a probe, and a markedly decrease in live bacteria was appreciated when PACT was applied. The use of amoxi@AuNP for PACT allows the viability reduction of clinical Gram positive and Gram negative biofilms. This novel strategy needs shorter irradiation times and lower concentrations of nanoparticles than other reports described. This could be attributed to two major innovations: the selectivity for the bacterial wall given by the amoxicillin and the polydispersity of size and shapes with seems to contribute to the photo-antibacterial capacity.}, } @article {pmid32439563, year = {2020}, author = {Hans, S and Purkait, D and Nandan, S and Bansal, M and Hameed, S and Fatima, Z}, title = {Rec A disruption unveils cross talk between DNA repair and membrane damage, efflux pump activity, biofilm formation in Mycobacterium smegmatis.}, journal = {Microbial pathogenesis}, volume = {149}, number = {}, pages = {104262}, doi = {10.1016/j.micpath.2020.104262}, pmid = {32439563}, issn = {1096-1208}, mesh = {Antitubercular Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; DNA Repair ; *Mycobacterium smegmatis/genetics ; *Mycobacterium tuberculosis/genetics ; }, abstract = {Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) has emerged in recent decades as one of the leading causes of mortality worldwide. The burden of TB is alarmingly high, with one third affected global population as reported by WHO. Short-course treatment with an antibiotic is a powerful weapon to treat infection of susceptible MTB strain, however; MTB has developed resistance to anti-TB drugs, which is an escalating global health crisis. Thus there is urgent need to identify new drug targets. RecA is a 38 kilodalton protein required for the repair and maintenance of DNA and regulation of the SOS response. The objective of this study is to understand the effect of disruption of RecA gene (deletion mutant ΔdisA from previous study) in a surrogate model for MTB, Mycobacterium smegmatis. This study demonstrated that disruption of RecA causes enhanced susceptibility towards rifampicin and generation of ROS leading to lipid peroxidation and impaired membrane homeostasis as depicted by altered cell membrane permeability and efflux pump activity. Mass spectrometry based lipidomic analysis revealed decreased mycolic acid moieties, phosphatidylinositol mannosides (PIM), Phthiocerol dimycocerosate (DIM). Furthermore, biofilm formation was considerably reduced. Additionally, we have validated all the disrupted phenotypes by RT-PCR which showed a good correlation with the biochemical assays. Lastly, RecA mutant displayed reduced infectivity in Caenorhabditis elegans illustrating its vulnerability as antimycobacterial target. Together, present study establishes a link between DNA repair, drug efflux and biofilm formation and validates RecA as an effective drug target. Intricate studies are needed to further understand and exploit this therapeutic opportunity.}, } @article {pmid32437832, year = {2020}, author = {Tang, M and Wei, X and Wan, X and Ding, Z and Ding, Y and Liu, J}, title = {The role and relationship with efflux pump of biofilm formation in Klebsiella pneumoniae.}, journal = {Microbial pathogenesis}, volume = {147}, number = {}, pages = {104244}, doi = {10.1016/j.micpath.2020.104244}, pmid = {32437832}, issn = {1096-1208}, mesh = {*Anti-Bacterial Agents/pharmacology ; Biofilms ; China ; Humans ; *Klebsiella pneumoniae ; Microbial Sensitivity Tests ; }, abstract = {This study aimed to identify the role and relationship with efflux pump of biofilm formation in Klebsiella pneumoniae. Sixty-one K. pneumoniae clinical isolates were collected between January and June of 2017 from the affiliated hospital of southwest medical university in Luzhou, China. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) were determined using broth microdilution method. Crystal violet (CV) staining and confocal laser scanning microscope (CLSM) were used to monitor biofilm formation. Efflux pump expression was investigated qualitatively and quantitatively by polymerase chain reaction (PCR) and reverse transcriptase quantitative PCR (RT-qPCR). Crystal violet staining was performed to evaluate the effect of efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazine (CCCP) on K. pneumoniae biofilms. Our results showed that crystal violet staining and CLSM had good consistency in biofilm detection. Biofilm formation was an independent biological behavior of the strain and measured at 24 h was reasonable. Biofilms up-regulated antimicrobial resistance and expression of efflux pump gene acrA, emrB, oqxA, and qacEΔ1 in K. pneumoniae. CCCP inhibited biofilms but dose-dependent effect was obvious. Altogether, our data demonstrates that biofilm formation, as well as its interaction with efflux pump, promotes antimicrobial resistance in K. pneumoniae.}, } @article {pmid32434379, year = {2020}, author = {Yang, D and Reyes-De-Corcuera, JI}, title = {Continuous flow system for biofilm formation using controlled concentrations of Pseudomonas putida from chicken carcass and coupled to electrochemical impedance detection.}, journal = {Biofouling}, volume = {36}, number = {4}, pages = {389-402}, doi = {10.1080/08927014.2020.1763966}, pmid = {32434379}, issn = {1029-2454}, mesh = {Animals ; *Biofilms ; Chickens/microbiology ; Electric Impedance ; *Pseudomonas putida ; }, abstract = {Most studies dealing with monitoring the dynamics of biofilm formation use microbial suspensions at high concentrations. These conditions do not always represent food or water distribution systems. A continuous flow system capable of controlling the concentration of the microbial suspension stream from 10[4] to 10[6] CFU ml[-1] is reported. Pseudomonas putida biofilms formed using 100-fold, 1,000-fold or 10,000-fold diluted bacterial suspensions were monitored in-line by electrochemical impedance spectroscopy (EIS) and total plate counts. Randles equivalent circuit model and a modified Randles model with biofilm elements were used to fit the EIS data. In Randles equivalent circuit, the charge transfer resistance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the charge transfer resistance. In the biofilm model, the biofilm resistance and the double layer capacitance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the biofilm resistance.}, } @article {pmid32433466, year = {2020}, author = {Dong, Y and Li, S and Zhao, D and Liu, J and Ma, S and Geng, J and Lu, C and Liu, Y}, title = {IolR, a negative regulator of the myo-inositol metabolic pathway, inhibits cell autoaggregation and biofilm formation by downregulating RpmA in Aeromonas hydrophila.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {22}, pmid = {32433466}, issn = {2055-5008}, mesh = {Aeromonas hydrophila/genetics/*physiology ; Bacterial Proteins/chemistry/*genetics ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Inositol/*metabolism ; Metabolic Networks and Pathways ; Models, Molecular ; Protein Conformation ; Sequence Analysis, RNA ; Virulence Factors ; }, abstract = {Aeromonas hydrophila is the causative agent of motile Aeromonad septicemia in fish. Previous studies have shown that the myo-inositol metabolism is essential for the virulence of this bacterium. IolR is a transcription inhibitor that negatively regulates myo-inositol metabolic activity. While in the process of studying the inositol catabolism in A. hydrophila Chinese epidemic strain NJ-35, we incidentally found that ΔiolR mutant exhibited obvious autoaggregation and increased biofilm formation compared to the wild type. The role of surface proteins in A. hydrophila autoaggregation was confirmed by different degradation treatments. Furthermore, calcium promotes the formation of aggregates, which disappear in the presence of the calcium chelator EGTA. Transcriptome analysis, followed by targeted gene deletion, demonstrated that biofilm formation and autoaggregation caused by the inactivation of iolR was due to the increased transcription of a RTX-family adhesion gene, rmpA. Further, IolR was determined to directly regulate the transcription of rmpA. These results indicated that iolR is negatively involved in autoaggregation and biofilm formation in A. hydrophila, and this involvement was associated with its inhibition on the expression of rmpA.}, } @article {pmid32432813, year = {2020}, author = {Luze, H and Holzer, J and Nischwitz, SP and Kamolz, LP}, title = {The importance of in vivo biofilm models for clinical practice.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {28}, number = {4}, pages = {578-579}, doi = {10.1111/wrr.12819}, pmid = {32432813}, issn = {1524-475X}, mesh = {*Biofilms ; *Wound Healing ; }, } @article {pmid32432137, year = {2020}, author = {Ma, Q and Wang, H and Chen, ZN and Wu, YQ and Yu, DZ and Wang, PJ and Shi, HB and Su, KM}, title = {Removal of biofilm is essential for long-term ventilation tube retention.}, journal = {World journal of clinical cases}, volume = {8}, number = {9}, pages = {1592-1599}, pmid = {32432137}, issn = {2307-8960}, abstract = {BACKGROUND: Although long-term retention of a ventilation tube is required in many ear diseases, spontaneous removal of conventional ventilation tube is observed in patients within 3 to 12 mo. To address this issue, we aimed to determine a new method for long-term retention of the ventilation tube.

AIM: To explore the value of removing the biofilm for long-term retention of tympanostomy ventilation tubes.

METHODS: A case-control study design was used to evaluate the safety and effectiveness of long-term tube retention by directly removing the biofilm (via surgical exfoliation) in patients who underwent myringotomy with ventilation tube placement. The patients were randomly divided into two groups: Control group and treatment group. Patients in the treatment group underwent regular biofilm exfoliation surgery in the clinic, whereas those in the control group did not have their biofilm removed. Only conventional ventilation tubes were placed in this study. Outcome measures were tube position and patency. Tube retention time and any complications were documented.

RESULTS: Eight patients with biofilm removal and eight patients without biofilm removal as a control group were enrolled in the study. The tympanostomy tube retention time was significantly longer in the treatment group (43.5 ± 26.4 mo) than in the control group (9.5 ± 6.9 mo) (P = 0.003). More tympanostomy tubes were found to be patent and in correct position in the treatment group during the follow-up intervals than in the control group (P = 0.01).

CONCLUSION: Despite the use of short-term ventilation tubes, direct biofilm removal can be a well-tolerated and effective treatment for long-term tube retention of tympanostomy ventilation tubes in patients who underwent myringotomy.}, } @article {pmid32432073, year = {2020}, author = {Soukarieh, F and Liu, R and Romero, M and Roberston, SN and Richardson, W and Lucanto, S and Oton, EV and Qudus, NR and Mashabi, A and Grossman, S and Ali, S and Sou, T and Kukavica-Ibrulj, I and Levesque, RC and Bergström, CAS and Halliday, N and Mistry, SN and Emsley, J and Heeb, S and Williams, P and Cámara, M and Stocks, MJ}, title = {Hit Identification of New Potent PqsR Antagonists as Inhibitors of Quorum Sensing in Planktonic and Biofilm Grown Pseudomonas aeruginosa.}, journal = {Frontiers in chemistry}, volume = {8}, number = {}, pages = {204}, pmid = {32432073}, issn = {2296-2646}, support = {/WT_/Wellcome Trust/United Kingdom ; }, abstract = {Current treatments for Pseudomonas aeruginosa infections are becoming less effective because of the increasing rates of multi-antibiotic resistance. Pharmacological targeting of virulence through inhibition of quorum sensing (QS) dependent virulence gene regulation has considerable therapeutic potential. In P. aeruginosa, the pqs QS system regulates the production of multiple virulence factors as well as biofilm maturation and is a promising approach for developing antimicrobial adjuvants for combatting drug resistance. In this work, we report the hit optimisation for a series of potent novel inhibitors of PqsR, a key regulator of the pqs system, bearing a 2-((5-methyl-5H-[1,2,4]triazino[5,6-b]indol-3-yl)thio) acetamide scaffold. The initial hit compound 7 (PAO1-L IC50 0.98 ± 0.02 μM, PA14 inactive at 10 μM) was obtained through a virtual screening campaign performed on the PqsR ligand binding domain using the University of Nottingham Managed Chemical Compound Collection. Hit optimisation gave compounds with enhanced potency against strains PAO1-L and PA14, evaluated using P. aeruginosa pqs-based QS bioreporter assays. Compound 40 (PAO1-L IC50 0.25 ± 0.12 μM, PA14 IC50 0.34 ± 0.03 μM) is one of the most potent PqsR antagonists reported showing significant inhibition of P. aeruginosa pyocyanin production and pqs system signaling in both planktonic cultures and biofilms. The co-crystal structure of 40 with the PqsR ligand binding domain revealed the specific binding interactions occurring between inhibitor and this key regulatory protein.}, } @article {pmid32431810, year = {2020}, author = {Pijls, BG and Sanders, IMJG and Kujiper, EJ and Nelissen, RGHH}, title = {Induction heating for eradicating Staphylococcus epidermidis from biofilm.}, journal = {Bone & joint research}, volume = {9}, number = {4}, pages = {192-199}, pmid = {32431810}, issn = {2046-3758}, abstract = {AIMS: Induction heating is a noninvasive, nonantibiotic treatment modality that can potentially be used to cause thermal damage to the bacterial biofilm on the metal implant surface. The purpose of this study was to determine the effectiveness of induction heating on killing Staphylococcus epidermidis from biofilm and to determine the possible synergistic effect of induction heating and antibiotics.

METHODS: S. epidermidis biofilms were grown on titanium alloy (Ti6Al4V) coupons for 24 hours (young biofilm) and seven days (mature biofilm). These coupons with biofilm were heated to temperatures of 50°C, 55°C, 60°C, 65°C, 70°C, 80°C, and 90°C for 3.5 minutes and subsequently exposed to vancomycin and rifampicin at clinically relevant concentrations.

RESULTS: For the young biofilm, total eradication was observed at 65°C or higher for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. For the mature biofilm, total eradication was observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. Total eradication was also observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 1 mg/l and rifampicin 1 mg/l followed by another thermal shock of 60°C for 3.5 minutes (two thermal shocks).

CONCLUSION: Induction heating of Ti6Al4V coupons is effective in reducing bacterial load in vitro for S. epidermidis biofilms. Induction heating and antibiotics have a synergistic effect resulting in total eradication of the biofilm at 60°C or higher for clinically relevant concentrations of vancomycin and rifampicin.Cite this article: Bone Joint Res. 2020;9(4):192-199.}, } @article {pmid32431213, year = {2021}, author = {Said, MB and Saad, MB and Bousselmi, L and Ghrabi, A}, title = {Use of the catalytic complex TiO2/red cabbage anthocyanins to reduce the biofilm formation by planktonic bacteria.}, journal = {Environmental technology}, volume = {42}, number = {25}, pages = {4006-4014}, doi = {10.1080/09593330.2020.1771432}, pmid = {32431213}, issn = {1479-487X}, mesh = {*Anthocyanins/pharmacology ; Bacteria ; Biofilms ; *Brassica ; Plankton ; Titanium ; }, abstract = {The bacterial cells dwelling within the biofilm usually develop resistance against common disinfectants. In this current study, to improve the effectiveness of photocatalytic treatment, a natural sensitizer in combination with unsupported titanium dioxide nanoparticles (TiO2-NPs) was used to optimize the absorbance of NPs in the visible region and, to enhance the catalytic activity of the semiconductor. Different kinetic parameters were determined according to the first-order and the biphasic models to evaluate the ability of tested bacteria to form biofilm under different photocatalytic treatment conditions. As a result, the addition of red cabbage anthocyanins (RCA) as photosensitizer allows the enhancement of biocide activity of TiO2-NPs and the reduction of biofilm formation by tested bacteria.}, } @article {pmid32429830, year = {2020}, author = {Souza, C and Mota, HF and Faria, YV and Cabral, FO and Oliveira, DR and Sant'Anna, LO and Nagao, PE and Santos, CDS and Moreira, LO and Mattos-Guaraldi, AL}, title = {Resistance to Antiseptics and Disinfectants of Planktonic and Biofilm-Associated Forms of Corynebacterium striatum.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {12}, pages = {1546-1558}, doi = {10.1089/mdr.2019.0124}, pmid = {32429830}, issn = {1931-8448}, mesh = {Adult ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Corynebacterium/*drug effects ; Cross Infection/prevention & control ; Disinfectants/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Plankton/*drug effects ; Virulence ; }, abstract = {Disinfection and antisepsis are of primary importance in controlling nosocomial infections and outbreaks by pathogens expressing multiple resistance to antimicrobial agents (multidrug-resistant [MDR]) used in therapy. Nowadays, infections related to health services (HAIs) due to MDR and multidrug-susceptible (MDS) Corynebacterium striatum should not be underestimated, including patients using invasive medical devices. The virulence potential of C. striatum needs further investigation. Currently, susceptibility profiles of planktonic and/or sessile forms of four C. striatum strains of different pulsed-field gel electrophoresis types were examined as biocides based on the manufacturer's recommendations: 2% glutaraldehyde (GA), 2% peracetic acid (PA), 1% potassium monopersulfate (Virkon[®]; VK), 1% sodium hypochlorite (SH), and 70% ethyl alcohol (ET). Time-kill assays using 2% bovine serum albumin (BSA) were performed for evaluation of influence of organic matter on biocides effects. Planktonic forms expressed GA resistance at different levels. C. striatum viability was observed until 2, 4, 20, and 30 min for MDR 2369/II, MDS 1954/IV, MDR 1987/I, and MDS 1961/III strains, respectively. In contrast to GA, the biocides PA, VK24h, SH, and ET had higher effective bacterial mortality. However, storage of VK (48 hr) reduced their biocide activities. Moreover, mature biofilms were produced on abiotic substrates, including steel surfaces. Post-treatment with GA (30 min), survival of sessile forms was ≥100% than planktonic forms of all C. striatum tested strains. Independent of biocides tested, BSA increased the survival of planktonic and sessile forms (p ≤ 0.005). Present data indicated that hospital staff should be aware of dissemination and eradication of HAIs by C. striatum presenting resistance to biocides, including high-level disinfectants, such as GA.}, } @article {pmid32429187, year = {2020}, author = {Bumunang, EW and Ateba, CN and Stanford, K and Niu, YD and Wang, Y and McAllister, TA}, title = {Activity of Bacteriophage and Complex Tannins against Biofilm-Forming Shiga Toxin-Producing Escherichia coli from Canada and South Africa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32429187}, issn = {2079-6382}, support = {FOS.07.17//Beef Cattle Research Council/ ; 98983//National Research Foundation of South Africa/ ; 001//Alberta Agriculture and Forestry, Growing Forward 2/ ; }, abstract = {Bacteriophages, natural killers of bacteria, and plant secondary metabolites, such as condensed tannins, are potential agents for the control of foodborne pathogens. The first objective of this study evaluated the efficacy of a bacteriophage SA21RB in reducing pre-formed biofilms on stainless-steel produced by two Shiga toxin-producing Escherichia coli (STEC) strains, one from South Africa and the other from Canada. The second objective examined the anti-bacterial and anti-biofilm activity of condensed tannin (CT) from purple prairie clover and phlorotannins (PT) from brown seaweed against these strains. For 24-h-old biofilms, (O113:H21; 6.2 log10 colony-forming units per square centimeter (CFU/cm[2]) and O154:H10; 5.4 log10 CFU/cm[2]), 3 h of exposure to phage (10[13] plaque-forming units per milliliter (PFU/mL)) reduced (p ≤ 0.05) the number of viable cells attached to stainless-steel coupons by 2.5 and 2.1 log10 CFU/cm[2] for O113:H21 and O154:H10, respectively. However, as biofilms matured, the ability of phage to control biofilm formation declined. In biofilms formed for 72 h (O113:H21; 5.4 log10 CFU/cm[2] and O154:H10; 7 log10 CFU/cm[2]), reductions after the same duration of phage treatment were only 0.9 and 1.3 log10 CFU/cm[2] for O113:H21 and O154:H10, respectively. Initial screening of CT and PT for anti-bacterial activity by a microplate assay indicated that both STEC strains were less sensitive (p ≤ 0.05) to CT than PT over a concentration range of 25-400 µg/mL. Based on the lower activity of CT (25-400 µg/mL), they were not further examined. Accordingly, PT (50 µg/mL) inhibited (p ≤ 0.05) biofilm formation for up to 24 h of incubation at 22 °C, but this inhibition progressively declined over 72 h for both O154:H10 and O113:H21. Scanning electron microscopy revealed that both SA21RB and PT eliminated 24 h biofilms, but that both strains were able to adhere and form biofilms on stainless-steel coupons at longer incubation times. These findings revealed that phage SA21RB is more effective at disrupting 24 than 72 h biofilms and that PT were able to inhibit biofilm formation of both E. coli O154:H10 and O113:H21 for up to 24 h.}, } @article {pmid32429151, year = {2020}, author = {Ingendoh-Tsakmakidis, A and Eberhard, J and Falk, CS and Stiesch, M and Winkel, A}, title = {In Vitro Effects of Streptococcus oralis Biofilm on Peri-Implant Soft Tissue Cells.}, journal = {Cells}, volume = {9}, number = {5}, pages = {}, pmid = {32429151}, issn = {2073-4409}, mesh = {*Biofilms ; Cell Adhesion ; Cell Shape ; Cell Survival ; Cytokines/metabolism ; Epithelial Cells/metabolism/*microbiology ; Fibroblasts/metabolism/*microbiology ; Gingiva/pathology ; Humans ; Inflammation Mediators/metabolism ; Prostheses and Implants/*microbiology ; Streptococcus oralis/*physiology ; Transcription, Genetic ; Up-Regulation/genetics ; }, abstract = {Human gingival epithelial cells (HGEps) and fibroblasts (HGFs) are the main cell types in peri-implant soft tissue. HGEps are constantly exposed to bacteria, but HGFs are protected by connective tissue as long as the mucosa-implant seal is intact. Streptococcus oralis is one of the commensal bacteria, is highly abundant at healthy implant sites, and might modulate soft tissue cells-as has been described for other streptococci. We have therefore investigated the effects of the S. oralis biofilm on HGEps and HGFs. HGEps or HGFs were grown separately on titanium disks and responded to challenge with S. oralis biofilm. HGFs were severely damaged after 4 h, exhibiting transcriptional inflammatory and stress responses. In contrast, challenge with S. oralis only induced a mild transcriptional inflammatory response in HGEps, without cellular damage. HGFs were more susceptible to the S. oralis biofilm than HGEps. The pro-inflammatory interleukin 6 (IL-6) was attenuated in HGFs, as was interleukin 8 (CXCL8) in HGEps. This indicates that S. oralis can actively protect tissue. In conclusion, commensal biofilms can promote homeostatic tissue protection, but only if the implant-mucosa interface is intact and HGFs are not directly exposed.}, } @article {pmid32428444, year = {2020}, author = {Riquelme, SA and Liimatta, K and Wong Fok Lung, T and Fields, B and Ahn, D and Chen, D and Lozano, C and Sáenz, Y and Uhlemann, AC and Kahl, BC and Britto, CJ and DiMango, E and Prince, A}, title = {Pseudomonas aeruginosa Utilizes Host-Derived Itaconate to Redirect Its Metabolism to Promote Biofilm Formation.}, journal = {Cell metabolism}, volume = {31}, number = {6}, pages = {1091-1106.e6}, pmid = {32428444}, issn = {1932-7420}, support = {R35 HL135800/HL/NHLBI NIH HHS/United States ; S10 RR027050/RR/NCRR NIH HHS/United States ; UL1 TR001863/TR/NCATS NIH HHS/United States ; UL1 TR001873/TR/NCATS NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Humans ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Pseudomonas aeruginosa/*metabolism ; Succinates/*metabolism ; }, abstract = {The bacterium Pseudomonas aeruginosa is especially pathogenic, often being associated with intractable pneumonia and high mortality. How P. aeruginosa avoids immune clearance and persists in the inflamed human airway remains poorly understood. In this study, we show that P. aeruginosa can exploit the host immune response to maintain infection. Notably, unlike other opportunistic bacteria, we found that P. aeruginosa alters its metabolic and immunostimulatory properties in response to itaconate, an abundant host-derived immunometabolite in the infected lung. Itaconate induces bacterial membrane stress, resulting in downregulation of lipopolysaccharides (LPS) and upregulation of extracellular polysaccharides (EPS). These itaconate-adapted P. aeruginosa accumulate lptD mutations, which favor itaconate assimilation and biofilm formation. EPS, in turn, induces itaconate production by myeloid cells, both in the airway and systemically, skewing the host immune response to one permissive of chronic infection. Thus, the metabolic versatility of P. aeruginosa needs to be taken into account when designing therapies.}, } @article {pmid32427342, year = {2020}, author = {Chatterjee, S and Samal, B and Singh, P and Pradhan, BB and Verma, RK}, title = {Transition of a solitary to a biofilm community life style in bacteria: a survival strategy with division of labour.}, journal = {The International journal of developmental biology}, volume = {64}, number = {4-5-6}, pages = {259-265}, doi = {10.1387/ijdb.190176sc}, pmid = {32427342}, issn = {1696-3547}, mesh = {Adaptation, Physiological/*physiology ; Bacteria/cytology/*metabolism ; Bacterial Adhesion/physiology ; Bacterial Proteins/metabolism/physiology ; Biofilms/*growth & development ; *Microbial Viability ; *Models, Biological ; Plant Leaves/microbiology ; Quorum Sensing/*physiology ; Xanthomonas/cytology/metabolism/physiology ; }, abstract = {Multicellularity is associated with higher eukaryotes having an organized division of labour and a coordinated action of different organs composed of multiple cell types. This division of different cell types and organizations to form a multicellular structure by developmental programming is a key to the multitasking of complex traits that enable higher eukaryotes to cope with fluctuating environmental conditions. Microbes such as bacteria, on the other hand, are unicellular and have flourished in diverse environmental conditions for a much longer time than eukaryotes in evolutionary history. In this review, we will focus on different strategies and functions exhibited by microbes that enable them to adapt to changes in lifestyle associated with transitioning from a unicellular solitary state to a complex community architecture known as a biofilm. We will also discuss various environmental stimuli and signaling processes which bacteria utilize to coordinate their social traits and enable themselves to form complex multicellular-like biofilm structures, and the division of labour operative within such communities driving their diverse social traits. We will also discuss here recent studies from our laboratory using a plant-associated bacterial pathogen as a model organism to elucidate the mechanism of bacterial cell-cell communication and the transition of a bacterial community to a multicellular-like structure driven by the complex regulation of traits influenced by cell density, as well as environmental sensing such as chemotaxis and nutrient availability. These studies are shedding important insights into bacterial developmental transitions and will help us to understand community cooperation and conflict using bacterial cell-cell communication as a model system.}, } @article {pmid32425915, year = {2020}, author = {Böttcher, B and Hoffmann, B and Garbe, E and Weise, T and Cseresnyés, Z and Brandt, P and Dietrich, S and Driesch, D and Figge, MT and Vylkova, S}, title = {The Transcription Factor Stp2 Is Important for Candida albicans Biofilm Establishment and Sustainability.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {794}, pmid = {32425915}, issn = {1664-302X}, abstract = {The fungal pathogen Candida albicans forms polymorphic biofilms where hyphal morphogenesis and metabolic adaptation are tightly coordinated by a complex intertwined network of transcription factors. The sensing and metabolism of amino acids play important roles during various phases of biofilm development - from adhesion to maturation. Stp2 is a transcription factor that activates the expression of amino acid permease genes and is required for environmental alkalinization and hyphal growth in vitro and during macrophage phagocytosis. While it is well established that Stp2 is activated in response to external amino acids, its role in biofilm formation remains unknown. In addition to widely used techniques, we applied newly developed approaches for automated image analysis to quantify Stp2-regulated filamentation and biofilm growth. Our results show that in the stp2Δ deletion mutant adherence to abiotic surfaces and initial germ tube formation were strongly impaired, but formed mature biofilms with cell density and morphological structures comparable to the control strains. Stp2-dependent nutrient adaptation appeared to play an important role in biofilm development: stp2Δ biofilms formed under continuous nutrient flow displayed an overall reduction in biofilm formation, whereas under steady conditions the mutant strain formed biofilms with lower metabolic activity, resulting in increased cell survival and biofilm longevity. A deletion of STP2 led to increased rapamycin susceptibility and transcriptional activation of GCN4, the transcriptional regulator of the general amino acid control pathway, demonstrating a connection of Stp2 to other nutrient-responsive pathways. In summary, the transcription factor Stp2 is important for C. albicans biofilm formation, where it contributes to adherence and induction of morphogenesis, and mediates nutrient adaption and cell longevity in mature biofilms.}, } @article {pmid32425911, year = {2020}, author = {Zhang, G and Lu, M and Liu, R and Tian, Y and Vu, VH and Li, Y and Liu, B and Kushmaro, A and Li, Y and Sun, Q}, title = {Inhibition of Streptococcus mutans Biofilm Formation and Virulence by Lactobacillus plantarum K41 Isolated From Traditional Sichuan Pickles.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {774}, pmid = {32425911}, issn = {1664-302X}, abstract = {Among cariogenic microbes, Streptococcus mutans is considered a major etiological pathogen of dental caries. Lactobacilli strains have been promoted as possible probiotic agents against S. mutans, although the inhibitory effect of Lactobacilli on caries has not yet been properly addressed. The objective of this study was to screen Lactobacillus strains found in traditional Sichuan pickles and to evaluate their antagonistic properties against S. mutans in vitro and in vivo. In the current study, we analyzed 54 Lactobacillus strains isolated from pickles and found that strain L. plantarum K41 showed the highest inhibitory effect on S. mutans growth as well as on the formation of exopolysaccharides (EPS) and biofilm in vitro. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) revealed the reduction of both EPS and of the network-like structure in S. mutans biofilm when these bacteria were co-cultured with strain L. plantarum K41. Furthermore, when rats were treated with strain L. plantarum K41, there was a significant reduction in the incidence and severity of dental caries. Due to K41's origin in a high salinity environment, it showed a high tolerance to acids and salts. This may give this strain an advantage in harsh oral conditions. Results showed that L. plantarum K41 isolated from traditional Sichuan pickles effectively inhibited S. mutans biofilm formation and thus possesses a potential inhibitory effect on dental caries in vivo.}, } @article {pmid32425737, year = {2020}, author = {Xu, X and Peng, Q and Zhang, Y and Tian, D and Zhang, P and Huang, Y and Ma, L and Qiao, Y and Shi, B}, title = {A novel exopolysaccharide produced by Lactobacillus coryniformis NA-3 exhibits antioxidant and biofilm-inhibiting properties in vitro.}, journal = {Food & nutrition research}, volume = {64}, number = {}, pages = {}, pmid = {32425737}, issn = {1654-661X}, abstract = {BACKGROUND: Exopolysaccharides (EPSs) secreted from lactic acid bacteria are carbohydrate polymers with reported biological activities. In this study, we extracted and characterized the composition as well as antioxidant and biofilm-inhibitory properties of EPS from Lactobacillus coryniformis NA-3 isolated from northeast Chinese sauerkraut (Suan Cai).

METHODS: Lactobacillus coryniformis NA-3 was identified with 16S rDNA amplification and Neighbor Joining (NJ) phylogenetic analysis. EPS derived from Lactobacillus coryniformis NA-3 (EPS-NA3) was analyzed, including compositions by high-performance liquid chromatography (HPLC), functional groups by Fourier-transform infrared spectroscopy (FT-IR) and glycosidic bond configuration by Hydrogen-1 Nuclear Magnetic Resonance ([1]H NMR). Antioxidant activity of EPS was evaluated with hydroxyl and superoxide radical-scavenging. Anti-biofilm activities of EPS-NA3 were checked through inhibition and dispersion.

RESULTS: The monosaccharide composition of EPS included α-rhamnose, α-mannose, α-galactose, and α-glucose in a ratio of 2.6:1.0:5.0:3.3. The free radical-scavenging abilities of EPS-NA3 were 37.77% ± 1.56% and 78.87% ± 3.07% on hydroxyl and superoxide reactive oxygen species respectively. Moreover, EPS-NA3 attenuated the formation of Bacillus cereus and Salmonella typhimurium biofilms by inhibition ratios of approximately 80% and 40% respectively. Additionally, treatment with EPS-NA3 dispersed established biofilms of B. cereus and S. typhimurium by approximately 90% and 20% respectively.

CONCLUSION: These results suggest that EPS-NA3 may be developed as antioxidant and anti-biofilm agents for industrial and clinical applications due to its capacity of scavenging free radicals, inhibition of bacterial biofilm formation, and dispersion of established biofilms.}, } @article {pmid32424471, year = {2020}, author = {Julák, J and Vaňková, E and Válková, M and Kašparová, P and Masák, J and Scholtz, V}, title = {Combination of non-thermal plasma and subsequent antibiotic treatment for biofilm re-development prevention.}, journal = {Folia microbiologica}, volume = {65}, number = {5}, pages = {863-869}, pmid = {32424471}, issn = {1874-9356}, support = {Progress Q25//Charles University/ ; 17-15936S//GA CR/ ; }, mesh = {Alloys ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects ; Drug Resistance, Microbial ; Escherichia coli/drug effects ; Microbial Sensitivity Tests ; Plasma Gases/*pharmacology ; Species Specificity ; Staphylococcus epidermidis/drug effects ; Titanium ; }, abstract = {The influence of non-thermal plasma (NTP) treatment on the prevention of antibiotic resistance of microbial biofilms was studied. Staphylococcus epidermidis and Escherichia coli bacteria and a yeast Candida albicans, grown on the surface of Ti-6Al-4V alloy used in the manufacture of prosthetic implants, were employed. Their biofilms were exposed to NTP produced by DC cometary discharge and subsequently treated with antibiotics commonly used for the treatment of infections caused by them: erythromycin (ERY), polymyxin B (PMB), or amphotericin B (AMB), respectively. All biofilms displayed significant reduction of their metabolic activity after NTP exposure, the most sensitive was S. epidermidis. The subsequent action of antibiotics caused significant decrease in the metabolic activity of S. epidermidis and E. coli, but not C. albicans, although the area covered by biofilm decreased in all cases. The combined effect of NTP with antibiotics was thus proved to be a promising strategy in bacterial pathogen treatment.}, } @article {pmid32422308, year = {2020}, author = {Falkinham, JO}, title = {Disinfection and cleaning of heater-cooler units: suspension- and biofilm-killing.}, journal = {The Journal of hospital infection}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.jhin.2020.05.005}, pmid = {32422308}, issn = {1532-2939}, abstract = {BACKGROUND: Non-tuberculous mycobacteria (NTM) infections in cardiac surgery patients, caused by Mycobacterium chimaera or Mycobacterium abscessus, have been traced to NTM-aerosols produced by heater-cooler units of cardiopulmonary bypass equipment.

AIM: To develop a protocol to disinfect the water reservoir(s) of heater-coolers to reduce NTM numbers and thereby prevent potential NTM aerosolization; and to devise an approach to disrupt surface biofilms of heater-coolers to reduce reinoculation of the heater-cooler reservoir(s) after disinfection.

METHODS: A laboratory-scale Centers for Disease Control and Prevention bioreactor and a heater-cooler were inoculated with M. chimaera or M. abscessus to measure the ability of different disinfection protocols to reduce NTM colony-forming units in water and biofilm samples and to delay the reappearance of NTM after disinfection.

FINDINGS: The combination of an enzyme detergent cleaning agent and Clorox® were equivalent to Clorox alone in reducing M. chimaera cfu in heater-cooler water reservoir samples. However, reappearance of those bacteria was delayed by 12 weeks by the combination of enzyme detergent cleaning agent and Clorox exposure compared to Clorox disinfection alone.

CONCLUSION: A combination of an enzyme detergent and Clorox was an effective disinfection treatment and significantly delayed the reappearance of M. chimaera in the heater-cooler reservoir.}, } @article {pmid32420501, year = {2020}, author = {Venkata, S and Zeeshan, F and Kamal, A and Luqman, AK and Saif, H}, title = {Efficiency of vanillin in impeding metabolic adaptability and virulence of Candida albicans by inhibiting glyoxylate cycle, morphogenesis, and biofilm formation.}, journal = {Current medical mycology}, volume = {6}, number = {1}, pages = {1-8}, pmid = {32420501}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: Candida albicans is the fourth most common cause of nosocomial fungal infections across the world. The current drug regimens are suffering from such drawbacks as drug resistance, toxicity, and costliness; accordingly, they highlight the need for the discovery of novel drug agents. The metabolic adaptability under low-carbon conditions and expression of functional virulence traits mark the success of pathogens to cause infection. The metabolic pathways, such as glyoxylate cycle (GC), enable C. albicans to survive under glucose-deficient conditions prevalent in the hostile niche. Therefore, the key enzymes, namely isocitrate lyase (ICL) and malate synthase (MLS), represent attractive agents against C. albicans. Similarly, virulence traits, such as morphogenesis and biofilm formation, are the crucial determinants of C. albicans pathogenicity. Regarding this, the present study was conducted to uncover the role of vanillin (Van), a natural food flavoring agent, in inhibiting GC, yeast-to-hyphal transition, and biofilm formation in human fungal pathogen C. albicans.

MATERIALS AND METHODS: For the determination of hypersensitivity under low-glucose conditions, phenotypic susceptibility assay was utilized. In addition, enzyme activities were estimated based on crude extracts while in-silico binding was confirmed by molecular docking. The assessment of morphogenesis was accomplished using hyphal-inducing media, and biofilm formation was estimated using calcofluor staining, MTT assay, and biomass measurement. Additionally, the in vivo efficacy of Van was demonstrated using Caenorhabditis elegans nematode model.

RESULTS: Based on the results, Van was found to be a potent GC inhibitor that phenocopied ICL1 deletion mutant and displayed hypersensitivity under low-carbon conditions. Accordingly, Van facilitated the inhibition of ICL and MLS activities in vitro. Molecular docking analyses revealed the in-silico binding affinity of Van with Icl1p and Mls1p. Those analyses were also confirmative of the binding of Van to the active sites of both proteins with better binding energy in comparison to their known inhibitors. Furthermore, Van led to the attenuation of such virulence traits as morphogenesis, biofilm formation, and cell adherence. Finally, the antifungal efficacy of Van was demonstrated by the enhanced survival of C. elegans with Candida infection. The results also confirmed negligible hemolytic activity on erythrocytes.

CONCLUSION: As the findings of the present study indicated, Van is a persuasive natural compound that warrants further attention to exploit its anticandidal potential.}, } @article {pmid32419108, year = {2020}, author = {Romiyo, V and Wilson, JW}, title = {Phenotypes, transcriptome, and novel biofilm formation associated with the ydcI gene.}, journal = {Antonie van Leeuwenhoek}, volume = {113}, number = {8}, pages = {1109-1122}, pmid = {32419108}, issn = {1572-9699}, support = {Dennis M. Cook Endowed Gregor Mendel Chair in Genetics//Villanova University/ ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; DNA-Binding Proteins/*genetics/*metabolism ; Escherichia coli/genetics/metabolism ; Escherichia coli Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial ; *Phenotype ; Regulon ; Salmonella typhimurium/genetics/metabolism ; Sequence Deletion ; Transcription Factors/*genetics/*metabolism ; *Transcriptome ; }, abstract = {The ydcI gene has previously been shown to encode a DNA-binding protein involved with acid stress resistance and induced biofilm formation in a strain of Salmonella enterica serovar Typhimurium. In addition, characterisation of the ydcI gene in Escherichia coli and other bacteria demonstrated strikingly different tolerance for induced ydcI expression across Gram negative species. In this report, we investigated the conservation of these phenotypes across multiple strains of S. Typhimurium and E. coli, and we used RNA Seq to identify the transcriptome of the ΔydcI mutant compared to WT in S. Typhimurium and E. coli (to establish the YdcI regulon in each species). We constructed deletion mutants in each species based on the RNA Seq results and tested these mutants for the relevant ydcI-related phenotypes. Though no evidence for a role in these phenotypes was found via the RNA Seq deletion mutants, we found that the ydcI-induced biofilm in S. Typhimurium is formed independently of the major biofilm genes csgA and bcsA indicating a potentially novel type of biofilm formation.}, } @article {pmid32418905, year = {2020}, author = {Khan, F and Lee, JW and Javaid, A and Park, SK and Kim, YM}, title = {Inhibition of biofilm and virulence properties of Pseudomonas aeruginosa by sub-inhibitory concentrations of aminoglycosides.}, journal = {Microbial pathogenesis}, volume = {146}, number = {}, pages = {104249}, doi = {10.1016/j.micpath.2020.104249}, pmid = {32418905}, issn = {1096-1208}, mesh = {Aminoglycosides/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; *Pseudomonas aeruginosa/cytology/drug effects/growth & development ; Quorum Sensing/drug effects ; Trans-Activators/metabolism ; Virulence/*drug effects ; }, abstract = {Aminoglycosides are a commonly used class of antibiotics; however, their application has been discontinued due to the emergence of multi-drug resistance bacterial strains. In the present study, the subinhibitory concentrations (sub-MIC) of several aminoglycosides were determined and tested as an antibiofilm and for their anti-virulence properties against Pseudomonas aeruginosa PAO1, which is an opportunistic foodborne pathogen. P. aeruginosa PAO1 exhibits multiple mechanisms of resistance, including the formation of biofilm and production of several virulence factors, against aminoglycoside antibiotics. The sub-MIC of these antibiotics exhibited biofilm inhibition of P. aeruginosa in alkaline TSB (pH 7.9). Moreover, various concentrations of these aminoglycosides also eradicate the mature biofilm of P. aeruginosa. In the presence of sub-MIC of aminoglycosides, the morphological changes of P. aeruginosa were found to change from rod-shaped to the filamentous, elongated, and streptococcal forms. Similar growth conditions and sub-MIC of aminoglycosides were also found to attenuate several virulence properties of P. aeruginosa PAO1. Molecular docking studies demonstrate that these aminoglycosides possess strong binding properties with the LasR protein, which is a well-characterized quorum-sensing receptor of P. aeruginosa. The present study suggests a new approach to revitalize aminoglycosides as antibiofilm and antivirulence drugs to treat infections caused by pathogenic bacteria.}, } @article {pmid32418125, year = {2020}, author = {van Geelen, L and Kaschani, F and Sazzadeh, SS and Adeniyi, ET and Meier, D and Proksch, P and Pfeffer, K and Kaiser, M and Ioerger, TR and Kalscheuer, R}, title = {Natural brominated phenoxyphenols kill persistent and biofilm-incorporated cells of MRSA and other pathogenic bacteria.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {13}, pages = {5985-5998}, pmid = {32418125}, issn = {1432-0614}, support = {270650915 / GRK2158//Deutsche Forschungsgemeinschaft/ ; KA 2259/5-1//Deutsche Forschungsgemeinschaft/ ; KA 2894/7-1//Deutsche Forschungsgemeinschaft/ ; N/A//Jürgen Manchot Stiftung/ ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects/growth & development ; Biological Products/chemistry/*pharmacology ; Cell Line ; Drug Resistance, Bacterial/drug effects/genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Mutation ; Phenols/chemistry/*pharmacology ; Phosphoenolpyruvate Sugar Phosphotransferase System/genetics ; Porifera/chemistry ; }, abstract = {Due to a high unresponsiveness to chemotherapy, biofilm formation is an important medical problem that frequently occurs during infection with many bacterial pathogens. In this study, the marine sponge-derived natural compounds 4,6-dibromo-2-(2',4'-dibromophenoxy)phenol and 3,4,6-tribromo-2-(2',4'-dibromophenoxy)phenol were found to exhibit broad antibacterial activity against medically relevant gram-positive and gram-negative pathogens. The compounds were not only bactericidal against both replicating and stationary phase-persistent planktonic cells of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa; they also killed biofilm-incorporated cells of both species while not affecting biofilm structural integrity. Moreover, these compounds were active against carbapenemase-producing Enterobacter sp. This simultaneous activity of compounds against different growth forms of both gram-positive and gram-negative bacteria is rare. Genome sequencing of spontaneous resistant mutants and proteome analysis suggest that resistance is mediated by downregulation of the bacterial EIIBC phosphotransferase components scrA and mtlA in MRSA likely leading to a lower uptake of the molecules. Due to their only moderate cytotoxicity against human cell lines, phenoxyphenols provide an interesting new scaffold for development of antimicrobial agents with activity against planktonic cells, persisters and biofilm-incoporated cells of ESKAPE pathogens. KEY POINTS: • Brominated phenoxyphenols kill actively replicating and biofilm-incorporated bacteria. • Phosphotransferase systems mediate uptake of brominated phenoxyphenols. • Downregulation of phosphotransferase systems mediate resistance.}, } @article {pmid32417953, year = {2021}, author = {Wang, J and Lu, J and Zhang, Y and Wu, J and Luo, Y}, title = {Unique Bacterial Community of the Biofilm on Microplastics in Coastal Water.}, journal = {Bulletin of environmental contamination and toxicology}, volume = {107}, number = {4}, pages = {597-601}, pmid = {32417953}, issn = {1432-0800}, support = {41671319//National Natural Science Foundation of China/ ; tsqn201812116//Taishan Scholars Program of Shandong Province/ ; Y739011021//Two-Hundred Talents Plan of Yantai/ ; QYZDJ-SSW-DQC015//Key Research Program of Frontier Sciences of CAS/ ; Y629041021//One Hundred Talents Program of Chinese Academy of Sciences/ ; }, mesh = {Biofilms ; *Microplastics ; *Plastics ; Silicon Dioxide ; Water ; }, abstract = {Being immersed in seawater for a few days, microorganisms will adhere to the surface of different materials and form biofilms. After being immersed in seawater for 1 week, high-throughput sequencing method was used to analyze the bacterial community structure of the biofilms on the surface of microbeads with different materials including steel, SiO2, and polyvinyl chloride (PVC). Operational taxonomic unit clustering results showed that some differences existed in the bacterial communities attached to the surface of different microbeads. Each microbead made by different material had its unique bacterial community. The heatmap indicated that the dominant genera on the surface of different microbeads were different from each other. Quantitative analysis showed that the relative abundance of dominant genera were different among different types of microbeads. Beta diversity analysis and principal component analysis showed that difference in the bacterial community on surface of steel-bead and PVC-bead was the most significant.}, } @article {pmid32417519, year = {2020}, author = {Luan, X and Zhang, H and Tian, Z and Yang, M and Wen, X and Zhang, Y}, title = {Microbial community functional structure in an aerobic biofilm reactor: Impact of streptomycin and recovery.}, journal = {Chemosphere}, volume = {255}, number = {}, pages = {127032}, doi = {10.1016/j.chemosphere.2020.127032}, pmid = {32417519}, issn = {1879-1298}, mesh = {Aerobiosis ; Anti-Bacterial Agents/analysis/*toxicity ; Biofilms/*drug effects/growth & development ; Bioreactors/*microbiology ; Carbon/metabolism ; Drug Resistance, Bacterial/drug effects/genetics ; Metagenome/drug effects ; Microbiota/*drug effects/genetics ; Nitrification ; Nitrogen/metabolism ; Streptomycin/analysis/*toxicity ; Wastewater/chemistry/microbiology ; Water Pollutants, Chemical/analysis/*toxicity ; Water Purification/*methods ; }, abstract = {Antibiotics can affect microbial community structure and promote antibiotic resistance. However, the course of microbial community recovery in wastewater treatment systems after antibiotic disturbance remains unclear. Herein, multiple molecular biology tools, including 16S amplicon sequencing, GeoChip 5.0, quantitative polymerase chain reaction (qPCR), and metagenomic sequencing, were used to investigate the year-long (352 d) recovery of the microbial community functional structure in an aerobic biofilm reactor. Nitrification was completely inhibited under 50 mg/L of streptomycin spiking (STM_50) due to the significant reduction of ammonia-oxidizing bacteria, but recovered to original pre-disturbance levels after streptomycin removal, indicating the high resilience of ammonia-oxidizing bacteria. Bacterial community richness and diversity decreased significantly under STM_50 (p < 0.05), but recovered to levels similar to those observed before disturbance after 352 d. In contrast, bacterial composition did not recover to the original structure. The carbon degradation and nitrogen cycling functional community significantly changed after recovery compared to that observed pre-disturbance (p < 0.05), thus indicating functional redundancy. Additionally, levels of aminoglycoside and total antibiotic resistance genes under STM_50 (relative abundance, 0.33 and 0.80, respectively) and after one year of recovery (0.12 and 0.29, respectively) were higher than the levels detected pre-disturbance (0.04 and 0.24, respectively). This study provides an overall depiction of the recovery of the microbial community functional structure after antibiotic exposure. Our findings give notice that recovery caused by antibiotic disturbance in the water environment should be taken more seriously, and that engineering control strategies should be implemented to prevent the antibiotic pollution of wastewater.}, } @article {pmid32417483, year = {2020}, author = {Xu, Y and Ou, Q and Zhou, X and He, Q and Wu, Z and Huang, R and Song, J and Ma, J and Huangfu, X}, title = {Impacts of carrier properties, environmental conditions and extracellular polymeric substances on biofilm formation of sieved fine particles from activated sludge.}, journal = {The Science of the total environment}, volume = {731}, number = {}, pages = {139196}, doi = {10.1016/j.scitotenv.2020.139196}, pmid = {32417483}, issn = {1879-1026}, mesh = {Biofilms ; *Extracellular Polymeric Substance Matrix ; Hydrophobic and Hydrophilic Interactions ; *Sewage ; Surface Properties ; }, abstract = {To investigate the effect of properties of carriers, environmental conditions and extracellular polymeric substances (EPS) on the initial adhesion of biofilm formation in biofilm-based reactors, a quartz crystal microbalance with dissipation (QCM-D) was applied to monitor the deposition rates and viscoelastic properties of sieved sludge particles on model biocarriers. The results suggested that surface charge, hydrophobicity and surface coating of five representative carriers influenced deposition rates and viscoelastic properties of biofilm, whose variation with NaCl concentrations was controlled by not only the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction but also non-DLVO forces. On hydrophobic surface, the addition of cationic substances enhanced the deposition rates and the compaction of deposited layer due to strong "hydrophobizing effect". For examples, 10 mM Ca[2+], 10 mM Mg[2+] and 10 mg/L poly-l-lysine enhanced the deposition rates to nearly 3, 2 and 4 times, as well as reduced the softness of deposited layer to almost 35%, 60% and 35%. Conversely, 10 mg/L negatively charged alginate might cause water retainment and steric shielding, thereby reducing the deposition rates to 40% and increasing the softness of deposited film to 120%. The presence of EPS sub-fractions can modify surface properties of sludge particles, to distinct degrees, contributing to biofilm formation. Notably, compared to tightly bound EPS (TB-EPS), loosely bound EPS (LB-EPS) was more conducive to microbial attachment, but the presence of LB-EPS promoted the formation of a soft layer on a hydrophobic surface. Overall, these results provide insights into intrinsic mechanisms of the variation of deposition rates and viscoelastic properties responding to critical factors, which are meaningful to predict and regulate the initial adhesion process in biofilm-based reactors.}, } @article {pmid32417469, year = {2020}, author = {Guo, L and Wang, J and Gou, Y and Tan, L and Liu, H and Pan, Y and Zhao, Y}, title = {Comparative proteomics reveals stress responses of Vibrio parahaemolyticus biofilm on different surfaces: Internal adaptation and external adjustment.}, journal = {The Science of the total environment}, volume = {731}, number = {}, pages = {138386}, doi = {10.1016/j.scitotenv.2020.138386}, pmid = {32417469}, issn = {1879-1026}, mesh = {Biofilms ; *Biological Phenomena ; Proteomics ; Stainless Steel ; *Vibrio parahaemolyticus ; }, abstract = {Vibrio parahaemolyticus is a kind of gram-negative marine pathogen, which usually adheres to stainless steel (SS), glass (GS) and other abiotic surfaces in aquaculture and food processing in the form of biofilm and causes the spread of gastrointestinal illness. However, the deeply survival adaptation mechanism of V. parahaemolyticus biofilm cells on these contact surface remained unclear. Here, proteomics was used to investigated the physiological response of the V. parahaemolyticus biofilms cells to different abiotic surfaces (SS, GS and polystyrene (PS)). In addition, the effect of contact materials on the physical-chemical properties of biofilms are also characterized. Results showed that the expression of proteins of biofilm cells established on the SS surface were mainly related to the alleviation of metal ion stress and toxicity. The up-regulated proteins in the biofilm cells formed on the GS surface were mainly involved in the biological processes of sugar uptake, protein synthesis and bacterial chemotaxis. Meanwhile, the significantly expressed proteins in the biofilm cells formed on the PS surface were mainly involved in the cellular physiological activity of aromatic compound metabolism, osmotic stress and nutrient transport. All functional proteins mentioned above were closely related to the interaction characteristics of the contact surface and biofilm. This study provided an in-depth comparison of V. parahaemolyticus biofilm formation on these three abiotic surfaces, and presented a model in first time for the adaptation behavior of biofilm cells on different surfaces as affected by metal ion stress, nutrition, osmotic stress, and sugar utilization, which could facilitate an efficient control strategy for biofilm formation in industrial field.}, } @article {pmid32417365, year = {2020}, author = {Pejčić, M and Stojanović-Radić, Z and Genčić, M and Dimitrijević, M and Radulović, N}, title = {Anti-virulence potential of basil and sage essential oils: Inhibition of biofilm formation, motility and pyocyanin production of Pseudomonas aeruginosa isolates.}, journal = {Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association}, volume = {141}, number = {}, pages = {111431}, doi = {10.1016/j.fct.2020.111431}, pmid = {32417365}, issn = {1873-6351}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; Ocimum basilicum/*chemistry ; Oils, Volatile/*pharmacology ; Pseudomonas aeruginosa/*drug effects/metabolism/pathogenicity ; Pyocyanine/*antagonists & inhibitors/biosynthesis ; Salvia officinalis/*chemistry ; Virulence/*drug effects ; }, abstract = {The effects of basil (Ocimum basilicum) and sage (Salvia officinalis) essential oils on selected virulence factors (biofilm formation, mature biofilm resistance, motility, and pyocyanin production) of Pseudomonas aeruginosa clinical isolates were evaluated in the present study for the first time. The two essential oils were chemically characterized by GC and GC-MS analyses. Linalool and (E)-anethole were found to be the main components of the investigated basil oil, while α-thujone and camphor were the major constituents of the studied sage essential oil. The oils inhibited biofilm formation up to 99.9% vs control, and significant reductions (74.7-99.9%) were also noted when the oils were applied to mature biofilms. Likewise, swimming, swarming, and twitching motility patterns were highly affected by both oils. The basil and sage oils reduced pyocyanin production by 13.32-55.6% and 5.0-58.7%, respectively. Thus, basil and sage essential oils are potentially highly efficient antipseudomonal agents that could be used against both acute and chronic infections.}, } @article {pmid32417013, year = {2020}, author = {Luo, W and Huang, Y and Zhou, X and Han, Q and Peng, X and Ren, B and Li, J and Li, M and Cheng, L}, title = {The effect of disaggregated nano-hydroxyapatite on oral biofilm in vitro.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {7}, pages = {e207-e216}, doi = {10.1016/j.dental.2020.04.005}, pmid = {32417013}, issn = {1879-0097}, mesh = {Biofilms ; *Durapatite ; Microscopy, Confocal ; *Nanostructures ; }, abstract = {OBJECTIVE: Agglomeration is a common problem facing the preparation and application of nanomaterials, and whether nano-hydroxyapatite (nano HA) can modulate oral microecology left to be unclear. In this study, nano HA was disaggregated by sodium hexametaphosphate (SHMP) and ultrasonic cavitation to observe whether agglomeration would affect its effect on oral bacterial biofilm.

METHODS: Dynamic light scattering (DLS) and scanning electronic microscope (SEM) were used to observe the treatment solutions. Single-species biofilms and multi-species biofilms were treated with 10% nano HA, 10% disaggregated nano HA, 10% micro hydroxyapatite (micro HA) and deionized water (DDW) for 30min and analyzed via MTT assay, lactic acid measurement, SEM and confocal laser scanning microscope (CLSM). Real-time polymerase chain reaction was performed to analyze the biofilm composition.

RESULTS: Ultrasonic cavitation combined with SHMP could significantly reduce the degree of agglomeration of nano HA. Disaggregated nano HA could inhibit bacterial growth and reduce the ability of bacterial biofilm to produce lactic acid and extracellular polysaccharides. There was no significant difference on composition of multi-species biofilms between nano HA and disaggregated nano HA.

SIGNIFICANCE: The disaggregated nano-hydroxyapatite could inhibit the metabolism and acid production of oral bacterial biofilm, but did not significantly affect the composition of multi-species biofilms.}, } @article {pmid32416355, year = {2020}, author = {Rahman, APH and Dash, S and Mohanty, PS and Mishra, A and Lundborg, CS and Tripathy, SK}, title = {Sonophotocatalytic disinfection of Shigella species under visible light irradiation: Insights into its molecular mechanism, antibacterial resistance and biofilm formation.}, journal = {Environmental research}, volume = {187}, number = {}, pages = {109620}, doi = {10.1016/j.envres.2020.109620}, pmid = {32416355}, issn = {1096-0953}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Disinfection ; Light ; *Shigella ; }, abstract = {Microbial contamination of water is one of the major sources of many diseases worldwide. Evolution of antibacterial resistance (ABR) alongside the caveats in most of the water treatment methods causes the severity of the current problem extremely vexing. This calls for an urgent need to develop new treatment methods aiming to reduce the microbial as well as ABR load in the environment. Herein, we successfully developed a visible light assisted sonophotocatalysis (SPC) using Fe/ZnO nanoparticles (NPs) for the disinfection of Shigella dysenteriae. A consortia containing S. dysenteriae and S. flexineri was also completely disinfected using SPC. Growth conditions of S. dysenteriae like growth phases and growth temperaturehad different outcomes on the overall efficacy of SPC. Compared with catalysts such as ZnO and TiO2, Fe/ZnO resulted in better disinfection. Multi-ROS production, mostly containing h[+] and O2· radicals, due to the electron displacement in the catalyst and acoustic cavitation was identified as the factors behind bacterial lethality. The ROS produced was found to interfere with the metabolic activities of S. dysenteriae by causing membrane perturbation. We identified DNA damage inside the cells and the subsequent release of intracellular components. The compositional changes in the fatty acid makeup of the cells were altered as a result of SPC and few fatty acid markers indicating the stress posed by SPC were also identified. Loss of ABR in S. dysenteriae was also recorded post SPC treatment. Abatement in the biofilm forming ability of the injured bacterial cells was also recorded, proving the extremity of stress induced by SPC. Hence, the excellent efficacy of SPC in disinfecting bacteria is proposed for tertiary water treatment applications.}, } @article {pmid32416351, year = {2020}, author = {Tantivitayakul, P and Kaypetch, R and Muadchiengka, T}, title = {Thymoquinone inhibits biofilm formation and virulence properties of periodontal bacteria.}, journal = {Archives of oral biology}, volume = {115}, number = {}, pages = {104744}, doi = {10.1016/j.archoralbio.2020.104744}, pmid = {32416351}, issn = {1879-1506}, mesh = {*Benzoquinones/pharmacology ; Biofilms ; *Fusobacterium nucleatum/drug effects ; *Porphyromonas gingivalis/drug effects ; Virulence ; }, abstract = {OBJECTIVES: To evaluate the effects of thymoquinone (TQ) on biofilm formation, hemolysis, hydrogen sulfide (H2S) production and expression of virulence factors of Fusobacterium nucleatum and Porphyromonas gingivalis.

MATERIALS AND METHODS: Reference strains of F. nucleatum ATCC 25586 and P. gingivalis A7436 were tested in our study. The minimum inhibitory concentration (MIC) of TQ was determined by broth microdilution method. The impacts of TQ on virulence properties of the periodontal bacteria including biofilm formation, hemolysis and H2S activities were studied. Quantitative RT-PCR was performed to evaluate the expression levels of key virulence factors including outer membrane proteins (aim-1, fadA) in F. nucleatum as well as cysteine proteinases or gingipains (rgpA, rgpB, kgp) and fimbriae (fimA, mfa1) in P. gingivalis.

RESULTS: The MIC of TQ were 12.5 and 1.56 μg/mL in F. nucleatum and P. gingivalis, respectively. The sub-MIC concentrations of TQ could prevent biofilm formation and hemolysis activities of both bacteria. TQ also inhibited H2S production which is highly associated with oral malodour. Scanning electron microscopy revealed that TQ could disrupt bacterial membrane and led to cell lysis. Furthermore, TQ reduced the expression of major virulence factors tested in F. nucleatum and P. gingivalis.

CONCLUSIONS: The TQ had potent antibacterial effect and could attenuate virulence properties of F. nucleatum and P. gingivalis. Therefore, TQ has the potential to be developed and used in periodontal treatments, especially to prevent the progression of periodontitis.}, } @article {pmid32415949, year = {2020}, author = {Zhang, L and Jin, M and Sun, M}, title = {Inhibition characteristics of biofilm structure of Staphylococcus aureus.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {66}, number = {2}, pages = {204-211}, pmid = {32415949}, issn = {1165-158X}, mesh = {Acetic Acid/chemistry ; Alkanes/chemistry ; *Biofilms ; Cell Membrane/metabolism ; Staphylococcus aureus/*physiology ; }, abstract = {Different extracts have different effects on the biofilm structure of Staphylococcus aureus, and the biofilm structure of Staphylococcus aureus will produce different inhibition reactions. In this study, different experimental reagent extracts were used to analyze the inhibition characteristics of Staphylococcus aureus biofilm structure. The inhibition characteristics of bacterial biofilm structure were obtained by using the same bacteria species and the same experimental environment. The results showed that the chloroform extract had a good inhibitory effect on the biofilm structure, which could effectively inhibit the formation of biofilm; the acetic acid extract had an impact on the formation of biofilm, which was destructive to the biofilm; the petroleum ether extract had no effect on the formation of biofilm, that is, it had no inhibitory effect.}, } @article {pmid32415612, year = {2020}, author = {Iseppi, R and Feminò, R and Sabia, C and Messi, P}, title = {Evaluation of Bacterial Biofilm Removal Properties of MEDSTER 2000 Cold Sterilant on Different Materials.}, journal = {Advances in experimental medicine and biology}, volume = {1282}, number = {}, pages = {127-137}, doi = {10.1007/5584_2020_542}, pmid = {32415612}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Disinfection/methods ; *Surface Properties/drug effects ; }, abstract = {We studied the antibacterial and anti-biofilm properties of MEDSTER 2000, a pH neutral biodegradable mixed acidic peroxide disinfectant belonging to the class IIb medical device which has been designed for decontamination and cold sterilization of hospital instruments. The broth microdilution method was used to define the antibacterial activity against planktonic form of both classified bacteria and antibiotic resistant strains of clinical source, whereas effectiveness toward their biofilm was determined on mature biofilm, grown both on plastic and stainless steel surfaces. The results showed that for the planktonic form the antibacterial activity of MEDSTER 2000 was already observed after 10 min at the lowest concentration (0.1%), and this effect was not exposure-and/or concentration-dependent. After the same time of exposure at the concentration of 2% the disinfectant was able to completely eradicate all tested bacteria grown in sessile form on both surfaces, with a greater than 6 log CFU/cm[2] reduction in viable cells. This result is supported by the microscope observation by crystal violet and live/dead assays. For the high antibacterial and anti-biofilm ability emerged, MEDSTER 2000 could represent a new and more effective approach for semicritical devices that need a high-level disinfection and could not sustain the process of heat sterilization.}, } @article {pmid32415320, year = {2020}, author = {Benedek, T and Szentgyörgyi, F and Szabó, I and Farkas, M and Duran, R and Kriszt, B and Táncsics, A}, title = {Aerobic and oxygen-limited naphthalene-amended enrichments induced the dominance of Pseudomonas spp. from a groundwater bacterial biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {13}, pages = {6023-6043}, pmid = {32415320}, issn = {1432-0614}, support = {PD 128831//Nemzeti Kutatási Fejlesztési és Innovációs Hivatal/ ; ÚNKP-19-3-I//New National Excellence Program of the Ministry of Innovation and Technology/ ; NKFIH-1159-6/2019//Higher Education Institutional Excellence Program awarded by the Ministry of Human Capacities/ ; }, mesh = {Bacteria/classification/genetics/isolation & purification/metabolism ; Bacterial Proteins/genetics ; Biodegradation, Environmental ; *Biofilms/growth & development ; Dioxygenases/genetics ; Genetic Variation ; Groundwater/chemistry/*microbiology ; Microbiota ; Multienzyme Complexes/genetics ; Naphthalenes/analysis/*metabolism ; Oxygen/analysis/*metabolism ; Phylogeny ; Polycyclic Aromatic Hydrocarbons/metabolism ; Pseudomonas/classification/genetics/*isolation & purification/metabolism ; Water Pollutants, Chemical/metabolism ; }, abstract = {In this study, we aimed at determining the impact of naphthalene and different oxygen levels on a biofilm bacterial community originated from a petroleum hydrocarbon-contaminated groundwater. By using cultivation-dependent and cultivation-independent approaches, the enrichment, identification, and isolation of aerobic and oxygen-limited naphthalene degraders was possible. Results indicated that, regardless of the oxygenation conditions, Pseudomonas spp. became the most dominant in the naphthalene-amended selective enrichment cultures. Under low-oxygen conditions, P. veronii/P. extremaustralis lineage affiliating bacteria, and under full aerobic conditions P. laurentiana-related isolates were most probably capable of naphthalene biodegradation. A molecular biological tool has been developed for the detection of naphthalene 1,2-dioxygenase-related 2Fe-2S reductase genes of Gram-negative bacteria. The newly developed COnsensus DEgenerate Hybrid Oligonucleotide Primers (CODEHOP-PCR) technique may be used in the monitoring of the natural attenuation capacity of PAH-contaminated sites. A bacterial strain collection with prolific biofilm-producing and effective naphthalene-degrading organisms was established. The obtained strain collection may be applicable in the future for the development of biofilm-based bioremediation systems for the elimination of PAHs from groundwater (e.g., biofilm-based biobarriers).}, } @article {pmid32415073, year = {2020}, author = {Bamford, NC and Le Mauff, F and Van Loon, JC and Ostapska, H and Snarr, BD and Zhang, Y and Kitova, EN and Klassen, JS and Codée, JDC and Sheppard, DC and Howell, PL}, title = {Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {2450}, pmid = {32415073}, issn = {2041-1723}, support = {81361//CIHR/Canada ; 43998//CIHR/Canada ; FDN-159902//CIHR/Canada ; P41 GM111244/GM/NIGMS NIH HHS/United States ; FDN-154327//CIHR/Canada ; 123306//CIHR/Canada ; }, mesh = {Acetylation ; Amidohydrolases/*chemistry/*metabolism ; Amino Acid Sequence ; Aspergillus fumigatus/*enzymology/genetics/*physiology ; Biofilms/*growth & development ; Catalytic Domain ; Conserved Sequence ; Fungal Proteins/*chemistry/*metabolism ; Gene Expression Regulation, Fungal ; Glycosaminoglycans/biosynthesis ; Metals/metabolism ; Polysaccharides/*metabolism ; Protein Domains ; Structural Homology, Protein ; Structure-Activity Relationship ; Substrate Specificity ; Time Factors ; }, abstract = {The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes.}, } @article {pmid32414689, year = {2020}, author = {Iwahashi, J and Kamei, K and Watanabe, H}, title = {Disruption of Aspergillus fumigatus biofilm by Streptococcus pneumoniae: Mycelial fragmentation by hydrogen peroxide.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {26}, number = {8}, pages = {831-837}, doi = {10.1016/j.jiac.2020.03.015}, pmid = {32414689}, issn = {1437-7780}, mesh = {Aspergillosis/microbiology ; Aspergillus fumigatus/*drug effects/physiology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Extracellular Matrix/drug effects/metabolism ; Humans ; Hydrogen Peroxide/metabolism/*pharmacology ; Microscopy, Electron, Scanning ; Pneumococcal Infections/microbiology ; Streptococcus pneumoniae/drug effects/*metabolism/physiology ; Streptolysins/metabolism ; }, abstract = {Biofilm is a complex structure consisting of microorganisms such as bacteria, fungi and an extracellular matrix (ECM). Biofilms are involved in most microbial infections and show persistent resistance to antibiotic treatment and immune response. Both Aspergillus fumigatus and Streptococcus pneumoniae are colonizers that can form biofilms in the respiratory tract. These pathogens have been simultaneously isolated from the same patient, but their interaction is poorly understood. We observed morphological changes in single- and mixed-species biofilms prepared for confocal laser scanning microscopy and scanning electron microscopy (SEM). Pneumococci suppressed the development of a fungal biofilm, and it even disrupted a preformed fungal biofilm. When a preformed fungal biofilm was treated with pneumococci, the mycelial network was fragmented, and only bacteria could develop. SEM revealed that the fragmented mycelium was further disrupted into fine filaments as treatment time progressed, and that the ECM of the preformed fungal biofilm had disappeared. The pneumococcal culture supernatant contained mycelial fragmentation activity that was heat-sensitive. The culture supernatant of a mutant pneumococcal strain deficient in pneumolysin (Δply) also exhibited the mycelial fragmentation activity. Enolase and lactate oxidase, which are involved in glycolysis and hydrogen peroxide production, were identified in the culture supernatant of the Δply mutant. Neither the wild type nor the mutant strain could fragment the mycelium in the presence of catalase. These data suggest that hydrogen peroxide could fragment the mycelium and would terminate the co-existence of A. fumigatus and S. pneumoniae in biofilm.}, } @article {pmid32413811, year = {2020}, author = {Arun, D and Vimala, R and Devendranath Ramkumar, K}, title = {Investigating the microbial-influenced corrosion of UNS S32750 stainless-steel base alloy and weld seams by biofilm-forming marine bacterium Macrococcus equipercicus.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {135}, number = {}, pages = {107546}, doi = {10.1016/j.bioelechem.2020.107546}, pmid = {32413811}, issn = {1878-562X}, mesh = {Alloys/*chemistry ; *Biofilms ; *Corrosion ; Microscopy, Atomic Force ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Seawater/*microbiology ; Stainless Steel/*chemistry ; Staphylococcaceae/*metabolism/ultrastructure ; }, abstract = {This study investigates the microbial-influenced corrosion of UNS S32750 super-duplex stainless-steel joints fabricated using different welding methods. Herein, the samples were introduced into a medium inoculated with Macrococcus equipercicus isolated from a marine environment. Confocal laser scanning microscopy and atomic force microscopy were used to characterise the topography and formation of pits in the corroded samples, respectively. Potentiodynamic polarisation studies were conducted on both the base alloy and weld seams exposed for 30 and 60 days in the experimental system inoculated with M. equipercicus and un-inoculated system. Results indicate that the thickness of the biofilm formed due to this bacterium increased and became heterogeneous with an increase in the exposure time, thereby resulting in micro-pits. Bacterial colonisation was observed in all the coupons after exposure to the inoculated medium. Although micro-pits were observed in all the coupons, the base metal and flux-cored arc weld seams showed highest sensitivity to bacterial attack.}, } @article {pmid32413575, year = {2020}, author = {Patel, M and Srivastava, V and Ahmad, A}, title = {Dodonaea viscosa var angustifolia derived 5,6,8-trihydroxy-7,4' dimethoxy flavone inhibits ergosterol synthesis and the production of hyphae and biofilm in Candida albicans.}, journal = {Journal of ethnopharmacology}, volume = {259}, number = {}, pages = {112965}, doi = {10.1016/j.jep.2020.112965}, pmid = {32413575}, issn = {1872-7573}, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development/metabolism/ultrastructure ; Ergosterol/*biosynthesis ; Flavonoids/isolation & purification/*pharmacology ; Hyphae/*drug effects/growth & development ; Microbial Sensitivity Tests ; Plant Extracts/isolation & purification/*pharmacology ; *Sapindaceae/chemistry ; }, abstract = {Candida albicans is developing resistance to existing drugs increasing morbidity and mortality, which elevates an immediate need to explore new antifungal agents. Phytochemicals are an excellent source of therapeutic agents. We previously reported the antifungal activity of the crude extract of Dodonaea viscosa var. angustifolia Jacq. (DVA) from which a beneficial compound flavone: 5,6,8-trihydroxy-7,4' dimethoxy flavone (5,6,8-trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) abbreviated as TMMC, was extracted.

AIM OF THE STUDY: The present study evaluated the effect of a TMMC subfraction on biofilms, membrane stability, ergosterol biosynthesis and germ tube (GT) formation in Candida albicans.

MATERIALS AND METHODS: Extracts were prepared and fractionated to obtain purified TMMC. Minimum inhibitory concentrations of TMMC were obtained and subinhibitory concentrations were selected for further studies. Confocal laser scanning microscopy (CLSM) was performed to assess the effect of TMMC on membrane permeability and sterol deposition using propidium iodide (PI) and filipin stains, respectively.

RESULTS: Minimum inhibitory concentrations (MIC) and Minimum Fungicidal concentrations (MFC) of TMMC were 0.39 mg/mL and 1.56 mg/mL, respectively. TMMC inhibited biofilm formation and damaged mature biofilms at 0.39 mg/mL and 1.56 mg/mL, respectively. CLSM further confirmed the disruption and architectural changes in biofilms following treatment with TMMC. TMMC also inhibited GT formation and ergosterol biosynthesis in a concentration dependent manner, which was further confirmed by varying sterol distribution and membrane disruption in treated and untreated cells.

CONCLUSIONS: With the multiple targets at different concentrations, TMMC warrants its potential use as antifungal drug against C. albicans. However further studies using animal models and more mechanistic approaches will be required.}, } @article {pmid32410574, year = {2020}, author = {Peng, N and Cai, P and Mortimer, M and Wu, Y and Gao, C and Huang, Q}, title = {The exopolysaccharide-eDNA interaction modulates 3D architecture of Bacillus subtilis biofilm.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {115}, pmid = {32410574}, issn = {1471-2180}, support = {2016YFD0800206//National Basic Research Program of China (973 Program)/International ; 41877029//National Natural Science Foundation of China/International ; NAF\R1\191017//Royal Society-Newton Advanced Fellowship/International ; 2016YFD0800206//National Key Research Program of China/International ; 2019020701011469//Wuhan Science and Technology Bureau/International ; }, mesh = {Bacillus subtilis/drug effects/*physiology ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; DNA, Bacterial/*metabolism ; Deoxyribonuclease I/pharmacology ; Microscopy, Atomic Force ; Microscopy, Confocal ; Polysaccharides, Bacterial/*metabolism ; }, abstract = {BACKGROUND: Bacterial biofilms are surface-adherent microbial communities in which individual cells are surrounded by a self-produced extracellular matrix of polysaccharides, extracellular DNA (eDNA) and proteins. Interactions among matrix components within biofilms are responsible for creating an adaptable structure during biofilm development. However, it is unclear how the interactions among matrix components contribute to the construction of the three-dimensional (3D) biofilm architecture.

RESULTS: DNase I treatment significantly inhibited Bacillus subtilis biofilm formation in the early phases of biofilm development. Confocal laser scanning microscopy (CLSM) and image analysis revealed that eDNA was cooperative with exopolysaccharide (EPS) in the early stages of B. subtilis biofilm development, while EPS played a major structural role in the later stages. In addition, deletion of the EPS production gene epsG in B. subtilis SBE1 resulted in loss of the interaction between EPS and eDNA and reduced the biofilm biomass in pellicles at the air-liquid interface. The physical interaction between these two essential biofilm matrix components was confirmed by isothermal titration calorimetry (ITC).

CONCLUSIONS: Biofilm 3D structures become interconnected through surrounding eDNA and EPS. eDNA interacts with EPS in the early phases of biofilm development, while EPS mainly participates in the maturation of biofilms. The findings of this study provide a better understanding of the role of the interaction between eDNA and EPS in shaping the biofilm 3D matrix structure and biofilm formation.}, } @article {pmid32409992, year = {2020}, author = {Tak, S and Tiwari, A and Vellanki, BP}, title = {Identification of emerging contaminants and their transformation products in a moving bed biofilm reactor (MBBR)-based drinking water treatment plant around River Yamuna in India.}, journal = {Environmental monitoring and assessment}, volume = {192}, number = {6}, pages = {365}, doi = {10.1007/s10661-020-08303-4}, pmid = {32409992}, issn = {1573-2959}, support = {933-CED//NBCC/ ; }, mesh = {Biofilms ; *Bioreactors ; Environmental Monitoring ; India ; Rivers ; *Water Pollutants, Chemical ; *Water Purification ; }, abstract = {The prevalence of emerging contaminants of concern in water regimes is very common these days. High anthropogenic intervention is leading to occurrence of various types of microcontaminants of concern in drinking water systems. Their removal using conventional form of treatment systems employed in water treatment plants is not widely researched upon. Their fate in the conventional as well as advanced water treatment system needs to be focused upon for efficient and safe water disposal. Some compounds may leave the system unchanged or some might transform into much more toxic byproduct. Moreover, understanding level of occurrence of these emerging contaminants in source water bodies is also quintessential for assessing their fate in treatment plant itself as well as in the final treated water. Here in this study, the occurrence and removal of various classes of emerging contaminants were investigated in a moving bed biofilm reactor (MBBR)-based advanced drinking water treatment plant (ADWTP) alongside one conventional drinking water treatment plant, both of which use River Yamuna as the source of water. Non-target analysis utilizing high-performance liquid chromatography combined with time of flight (HPLC-QToF) identified more than 300 compounds. Pharmaceuticals accounted for a major fraction (58%) of the identified compounds, followed by plasticizers and insecticides. Nine parent compound and their transformation products were additionally identified using solid-phase extraction followed by analysis using gas chromatography mass spectrometry and HPLC-QToF. The degradation pathway of the parent compounds in MBBR-based ADWTP was also analyzed in depth. The efficiency of each unit process of MBBR-based drinking water treatment plant was studied in terms of removal of few emerging contaminants. Pharmaceutical compound like diclofenac supposedly was persistent, even, toward the end of the treatment train. Semi-quantitative analysis revealed ineffective removal of pyridine, hydrochlorothiazide, and diethyl phthalate in the outlet of ADWTP. ADWTP was able to remove a few emerging contaminants, but a few were recalcitrant. Likewise, it was established that although some parent compounds were degraded, much more toxic transformation products were formed and were prevalent at the end of the treatment.}, } @article {pmid32409853, year = {2020}, author = {Saygin, H and Baysal, A}, title = {Biofilm Formation of Clinically Important Bacteria on Bio-Based and Conventional Micro/Submicron-Sized Plastics.}, journal = {Bulletin of environmental contamination and toxicology}, volume = {105}, number = {1}, pages = {18-25}, doi = {10.1007/s00128-020-02876-z}, pmid = {32409853}, issn = {1432-0800}, mesh = {Bacteria ; Biofilms ; Environmental Monitoring ; Humans ; Particle Size ; Plastics/*analysis ; Water Pollutants, Chemical/*analysis ; }, abstract = {Micron/submicron-sized plastic debris in the environment is a global issue of increasing concern and may harm human health. A large number of studies have shown that plastic debris has various toxicological effects on different organisms. Thus, efforts have increased to replace conventional plastics with bioplastics. However, investigations on the relation of submicron-sized bioplastics- and conventional plastics to culture-dependent biofilm formation and their similarities and discrepancies are still very limited. For this purpose, two end products made from bioplastics and their equivalent end products from conventional plastics were used to examine the response of the biofilm formation of selected clinically important bacteria. To evaluate the similarities and differences of submicron-sized bioplastics and conventional plastics on biofilm formation, the physicochemistry (particle size, zeta potential, chemical composition, and surface chemistry) of the tested plastics was examined, as well as the characteristics of the biofilms (categorization, protein/carbohydrate).}, } @article {pmid32408616, year = {2020}, author = {Naclerio, GA and Onyedibe, KI and Sintim, HO}, title = {Lipoteichoic Acid Biosynthesis Inhibitors as Potent Inhibitors of S. aureus and E. faecalis Growth and Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {10}, pages = {}, pmid = {32408616}, issn = {1420-3049}, support = {N/A//Purdue University/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; *Biofilms/drug effects/growth & development ; Enterococcus faecalis/*physiology ; Lipopolysaccharides/*biosynthesis ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Teichoic Acids/*biosynthesis ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10-10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria's ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation.}, } @article {pmid32408121, year = {2020}, author = {Yuan, L and Lyu, P and Huang, YY and Du, N and Qi, W and Hamblin, MR and Wang, Y}, title = {Corrigendum to "Potassium iodide enhances the photobactericidal effect of methylene blue on Enterococcus faecalis as planktonic cells and as biofilm infection in teeth" [J Photochem Photobiol B 203(2020) 1-11/111730].}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {207}, number = {}, pages = {111892}, doi = {10.1016/j.jphotobiol.2020.111892}, pmid = {32408121}, issn = {1873-2682}, } @article {pmid32408033, year = {2020}, author = {Zhu, C and Mahmood, Z and Zhang, W and Akram, MW and Ainur, D and Ma, H}, title = {In situ investigation of acute exposure of graphene oxide on activated sludge: Biofilm characteristics, microbial activity and cytotoxicity.}, journal = {Ecotoxicology and environmental safety}, volume = {199}, number = {}, pages = {110639}, doi = {10.1016/j.ecoenv.2020.110639}, pmid = {32408033}, issn = {1090-2414}, mesh = {Biofilms/*drug effects ; China ; Graphite/*toxicity ; Microbial Viability/*drug effects ; Reactive Oxygen Species/metabolism ; Sewage/chemistry/*microbiology ; Wastewater/chemistry/*microbiology ; Water Pollutants, Chemical/*toxicity ; Water Purification/methods ; }, abstract = {Graphene Oxide (GO) has wide applications in many fields which has caused a large expected quantity of the graphene-based wastes. It is necessary to understand the toxic effects of the GO on the activated sludge (AS) considering its inevitable discharge to the wastewater treatment plants as the ultimate repositories for these wastes. In this study, the acute exposures of the multilayer Nano-graphene oxide (MNGO) at different dosages were conducted in order to investigate its integrated effects on the formation of the biofilm, mature biofilm and the microbial activity of the activated sludge. Raman spectroscopy and laser scanning confocal microscopy (LSCM) were adopted for the in-situ characterization of the biofilm with the exposure of the MNGO. The results showed that the activated sludge was tolerable to the acute exposure of the less than 100 mg/L of the MNGO, especially for the mature biofilm, and only a subtle decrease was found in the size and thickness during the formation of the biofilm, while the amount of 300 mg/L of the MNGO caused the sever deterioration on the activated sludge system. The microbial metabolic activity, viability, and the biological removal of the nutrients were significantly affected with the more than 100 mg/L of the MNGO. It was also demonstrated by the microbial cytotoxicity tests that the increase in the exposure of the MNGO was related to the increase in the reactive oxygen species (ROS) and the damaging degree of the cell membrane.}, } @article {pmid32407890, year = {2020}, author = {Nie, M and Deng, DM and Wu, Y and de Oliveira, KT and Bagnato, VS and Crielaard, W and Rastelli, ANS}, title = {Photodynamic inactivation mediated by methylene blue or chlorin e6 against Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101817}, doi = {10.1016/j.pdpdt.2020.101817}, pmid = {32407890}, issn = {1873-1597}, mesh = {Biofilms ; Chlorophyllides ; Methylene Blue/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Porphyrins ; *Streptococcus mutans ; }, abstract = {BACKGROUND: An appropriate photosensitizer (PS) for photodynamic inactivation should have a pronounced antimicrobial efficacy but low dark toxicity. The aim of this study is to investigate the concentration-dependent antimicrobial efficacies of methylene blue (MB) and chlorin e6 (Ce6), against Streptococcus mutans biofilms and to compare the efficacies of these two PSs.

METHODS: The 48-h S. mutans UA159 biofilms, grown on glass coverslips, were subjected to MB or Ce6 at 25, 50, 100 and 200 μM with or without irradiation by 660 nM LED light (L). Control groups (-PS-L and -PS + L) were also included. Viability of the biofilm was analyzed by CFU/biofilm and biofilm lactic acid production was quantified by an enzymatic assay.

RESULTS: With irradiation, MB under 25 μM resulted in 2-log reduction in biofilm viability and 30-fold reduction in biofilm lactic acid production. However, this biofilm killing efficacy did not change with increasing MB concentration. The biofilm killing efficacy of Ce6 increased with increasing Ce6 concentrations and resulted in 5-log reduction in biofilm viability. The lactic acid inhibitory effect of Ce6 was significantly lower than MB at 25 μM (p<0.01) but higher than MB at 200 μM (p=0.05), although the difference at 200 μM did not reach statistical significance. No dark toxicity could be observed for MB whereas low dark toxicity could be seen for Ce6 when the concentration is above 50 μM.

CONCLUSION: Ce6 under 200 μM showed to be a more powerful PS for photodynamic inactivation than MB. Both Ce6- and MB-based photodynamic inactivation are useful methods for biofilm control in caries prevention.}, } @article {pmid32407475, year = {2021}, author = {Sánchez-Herrera, R and Flores-Villavicencio, LL and Pichardo-Molina, JL and Castruita-Domínguez, JP and Aparicio-Fernández, X and Sabanero López, M and Villagómez-Castro, JC}, title = {Analysis of biofilm formation by Sporothrix schenckii.}, journal = {Medical mycology}, volume = {59}, number = {1}, pages = {31-40}, doi = {10.1093/mmy/myaa027}, pmid = {32407475}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Extracellular Matrix/*physiology ; Humans ; Sporothrix/*growth & development ; Sporotrichosis/*physiopathology ; Virulence/*physiology ; }, abstract = {The development of mature biofilms is an aid in numerous aspects of the life cycle of fungi. It is well known that Sporothrix schenckii complex causes a benign subcutaneous mycosis, but recent studies have suggestedthat biofilm formation may be one of the important factors involved in its virulence. Here we report the study of the biomass organization and a model of the stages of S. schenckii biofilm development: adsorption, active adhesion, microcolony formation, maturation, and dispersal of biofilm fragments. During the development, the biofilm is surrounded by extracellular matrix, which contains glycoprotein (mannose rich), carbohydrates, lipids, and nucleic acid. In addition, the extracellular DNA increases in extracellular matrix as a key component to structural integrity and antifungal resistance. The study of S. schenckii biofilm contributes to a better understanding of growth biofilm and physiology, adding new insights into the mechanisms of virulence and persistence of pathogenic microorganisms.}, } @article {pmid32407362, year = {2020}, author = {Pestrak, MJ and Gupta, TT and Dusane, DH and Guzior, DV and Staats, A and Harro, J and Horswill, AR and Stoodley, P}, title = {Correction: Investigation of synovial fluid induced Staphylococcus aureus aggregate development and its impact on surface attachment and biofilm formation.}, journal = {PloS one}, volume = {15}, number = {5}, pages = {e0233534}, pmid = {32407362}, issn = {1932-6203}, abstract = {[This corrects the article DOI: 10.1371/journal.pone.0231791.].}, } @article {pmid32404511, year = {2020}, author = {Chakraborty, T and Tóth, Z and Tóth, R and Vágvölgyi, C and Gácser, A}, title = {Iron Metabolism, Pseudohypha Production, and Biofilm Formation through a Multicopper Oxidase in the Human-Pathogenic Fungus Candida parapsilosis.}, journal = {mSphere}, volume = {5}, number = {3}, pages = {}, pmid = {32404511}, issn = {2379-5042}, mesh = {Biofilms/*growth & development ; Candida parapsilosis/*genetics/*metabolism ; Fungal Proteins/genetics/*metabolism ; Genome, Fungal ; Homeostasis ; Humans ; Hyphae/physiology ; Iron/*metabolism ; Oxidoreductases/genetics/*metabolism ; Virulence ; Virulence Factors/genetics ; }, abstract = {Among all the essential micronutrients, iron plays an important role in mammalian biology. It is also essential for pathogens infecting mammalian hosts, including bacteria, fungi, and protozoans. As the availability of accessible iron is limited within the mammalian host, several human-pathogenic fungal pathogens, such as Candida albicans, Cryptococcus neoformans, Candida glabrata, and Aspergillus fumigatus, have developed various iron uptake mechanisms. Although Candida parapsilosis is the second or third most common non-albicans Candida species associated with systemic and superficial Candida infections in immunocompromised patients, the mechanisms of iron uptake and homoeostasis remain unknown in this fungus. In the current report, we show that a homologue of the multicopper oxidase gene FET3 is present in the genome of C. parapsilosis (CPAR2_603600) and plays a significant role in iron acquisition. We found that homozygous deletion mutants of CPAR2_603600 showed defects under low-iron conditions and were also sensitive to various stressors. Our results also revealed that the levels of pseudohypha formation and biofilm formation were reduced in the null mutants compared to the wild type. This phenotypic defect could be partially rescued by supplementation with excess iron in the growth medium. The expression levels of the orthologues of various iron metabolism-related genes were also altered in the mutants compared to the parental strain. In conclusion, our report describes the role of CPAR2_603600 in iron homoeostasis maintenance as well as morphology and biofilm formation regulation in this pathogenic fungus.IMPORTANCEC. parapsilosis is the second or third most common opportunistic human-pathogenic Candida species, being responsible for severe fungal infections among immunocompromised patients, especially low-birth-weight infants (0 to 2 years of age). Among the major virulence factors that pathogenic fungi possess is the ability to compete with the host for essential micronutrients, including iron. Accessible iron is required for the maintenance of several metabolic processes. In order to obtain accessible iron from the host, pathogenic fungi have developed several iron acquisition and metabolic mechanisms. Although C. parapsilosis is a frequent cause of invasive candidiasis, little is known about what iron metabolic processes this fungus possesses that could contribute to the species' virulent behavior. In this study, we identified the multicopper oxidase FET3 gene that regulates iron homeostasis maintenance and also plays important roles in the morphology of the fungus as well as in biofilm formation, two additional factors in fungal virulence.}, } @article {pmid32403300, year = {2020}, author = {Madaha, EL and Gonsu, HK and Bughe, RN and Fonkoua, MC and Ateba, CN and Mbacham, WF}, title = {Occurrence of blaTEM and blaCTXM Genes and Biofilm-Forming Ability among Clinical Isolates of Pseudomonas aeruginosa and Acinetobacter baumannii in Yaoundé, Cameroon.}, journal = {Microorganisms}, volume = {8}, number = {5}, pages = {}, pmid = {32403300}, issn = {2076-2607}, support = {0000//North-West University/ ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa (PSA) and Acinetobacter baumannii (ACB) are non-fermentative bacteria mostly associated with nosocomial infections in humans.

OBJECTIVE: This study aimed to determine the antimicrobial resistance profiles and virulence gene of PSA and ACB previously isolated from humans in selected health facilities in Yaoundé, Cameroon.

METHODS: A total of 77 and 27 presumptive PSA and ACB isolates, respectively, were collected from the Yaoundé teaching hospital. These isolates were previously isolated from various samples including pus, blood and broncho-alveolar lavage. The identities of the isolates were determined through polymerase chain reaction (PCR) amplification of PSA and ACB specific sequences. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disc diffusion method. Phenotypical expression of AmpC β-lactamases (AmpC), extended spectrum β-lactamases (ESBLs) and metallo β-Lactamases (MBLs) were determined using the combined disc method. Bacterial genomes were screened for the presence of β-lactamases blaTEM and blaCTXM genes using specific PCR. The pathogenicity of PSA and ACB was assessed through amplification of the lasB, exoA, pslA and exoS as well as OmpA and csuE virulence genes, respectively.

RESULTS: Of the 77 presumptive PSA isolates, a large proportion (75 to 97.4%) were positively identified. All (100%) of the presumptive 27 ACB harbored the ACB-specific ITS gene fragment by PCR. Twenty five percent of the PSA isolates produced ESBLs phenotypically while more than 90% of these isolates were positive for the lasB, exoA, pslA and exoS genes. A large proportion (88%) of the ACB isolates harboured the OmpA and csuE genes. blaTEM and blaCTXM were detected in 17 and 4% of PSA, respectively, while a much higher proportion (70 and 29%) of the ACB isolates possessed these resistance determinants respectively.

CONCLUSION: Our findings reveal the occurrence of both virulence and drug-resistant determinants in clinical PSA and ACB isolates from patients in health care settings in Yaoundé, Cameroon, thus suggesting their role in the pathological conditions in patients.}, } @article {pmid32403244, year = {2020}, author = {Francis, F and Druart, F and Mavungu, JDD and De Boevre, M and De Saeger, S and Delvigne, F}, title = {Biofilm Mode of Cultivation Leads to an Improvement of the Entomotoxic Patterns of Two Aspergillus Species.}, journal = {Microorganisms}, volume = {8}, number = {5}, pages = {}, pmid = {32403244}, issn = {2076-2607}, abstract = {Two fungi, i.e., Aspergillus flavus Link and Aspergillus oryzae (Ahlb.) E. Cohn, were cultivated according to two methodologies, namely submerged and biofilm cultures with the primary aim to use their secondary metabolites the supernatant CL50, and CL90 varied between 1.3% (v/v) to 12.7% (v/v) for incubation times from 24 to 72 h. While the A. flavus supernatant entomotoxicity was higher than this of A. oryzae, the biofilm culture application increased the efficiency of the former. Proteomic analysis of the supernatants revealed discrepancies among the two species and modes of cultivation. Furthermore, the secondary metabolite profiles of both Aspergillus cultures were verified. Aspergillic acid, beta-cyclopiazonic acid, cyclopiazonic acid, ferrineospergillin, flavacol, and spermadin A were most predominant. Generally, these secondary metabolites were present in higher concentrations in the supernatants of A. flavus and biofilm cultures. These molecular identifications correlated positively with entomotoxic activity. Noteworthy, the absence of carcinogenic aflatoxins was remarkable, and it will allow further valorization to produce A. flavus to develop potential biopesticides.}, } @article {pmid32403180, year = {2020}, author = {Subh, L and Correa, W and Pinkvos, TJ and Behrens, P and Brandenburg, K and Gutsmann, T and Stiesch, M and Doll, K and Winkel, A}, title = {Synthetic anti-endotoxin peptides interfere with Gram-positive and Gram-negative bacteria, their adhesion and biofilm formation on titanium.}, journal = {Journal of applied microbiology}, volume = {129}, number = {5}, pages = {1272-1286}, doi = {10.1111/jam.14701}, pmid = {32403180}, issn = {1365-2672}, support = {//Brandenburg Antiinfectiva GmbH/ ; //Volkswagen Foundation/ ; KF3382401CS4//Federal Ministry of Economic Affairs and Energy, Germany/ ; //Ministry of Economic Affairs/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; Cell Line ; Humans ; Peptides/chemistry/*pharmacology ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/microbiology/prevention & control ; Titanium/chemistry/*pharmacology ; }, abstract = {AIMS: Implant-associated infections arise from the formation of bacterial biofilms, which are difficult to be treated with conventional antibiotics. Therefore, there is a need for new implant functionalizations, which inhibit biofilm formation. The aim of the present study was to characterize the effect of synthetic peptides to assess their applicability for this purpose.

METHODS AND RESULTS: Two synthetic anti-endotoxin peptides, Pep19-2.5 and Pep19-4LF (Aspidasept I and II) were tested against both Gram-positive (Staphylococcus aureus and Streptococcus oralis) and Gram-negative (Pseudomonas aeruginosa and Aggregatibacter actinomycetemcomitans) bacteria associated with implant infections. Their activity was evaluated against different states of biofilm formation on the implant material titanium using CFU, live/dead fluorescence staining and confocal microscopy. Both peptides inhibited planktonic bacteria growth, impacted initial bacterial adhesion, reduced biofilm volume and increased the proportion of dead cells. Additionally, cytotoxicity analyses showed that neither peptide harmed human gingival fibroblasts nor osteoblasts at lower concentrations.

CONCLUSION: A concentration-dependent antibacterial activity of both peptides against biofilms of four clinically relevant bacteria could be demonstrated.

The results of this study serve as a promising basis for the improvement of these peptides in order to finally achieve a peptide-equipped antibacterial implant surface.}, } @article {pmid32402850, year = {2020}, author = {Tiwari, M and Panwar, S and Kothidar, A and Tiwari, V}, title = {Rational targeting of Wzb phosphatase and Wzc kinase interaction inhibits extracellular polysaccharides synthesis and biofilm formation in Acinetobacter baumannii.}, journal = {Carbohydrate research}, volume = {492}, number = {}, pages = {108025}, doi = {10.1016/j.carres.2020.108025}, pmid = {32402850}, issn = {1873-426X}, mesh = {Acinetobacter baumannii/*drug effects/metabolism ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Labetalol/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Conformation ; Phenols/chemistry/*pharmacology ; Polysaccharides/*antagonists & inhibitors/biosynthesis ; Protein Binding/drug effects ; Protein Tyrosine Phosphatases/*antagonists & inhibitors/chemistry/metabolism ; Protein-Tyrosine Kinases/*antagonists & inhibitors/chemistry/metabolism ; }, abstract = {Acinetobacter baumannii is an opportunistic nosocomial pathogen, and responsible for high mortality and morbidity. Biofilm formation is one of the resistance determinants, where extracellular polysaccharide (EPS) is an essential component. EPS synthesis and its export is regulated by the bacterial Wza-Wzb-Wzc system. Wzc exhibits auto-phosphorylation protein tyrosine kinase activity, while Wzb is a protein tyrosine phosphatase. Wzb mediates dephosphorylation of Wzc. Dephosphorylated Wzc is required for the export of the EPS through porin Wza-Wzc complex. It shows that the interaction of Wzb with Wzc is critical for the export of EPS. Therefore, if the Wzb-Wzc interaction is inhibited, then it might hinder the EPS transport and diminish the biofilm formation. In this study, we have modelled the Wzb, and Wzc proteins and further validated using PSVS, ProSA, RAMPAGE, and PDBsum. The modelled proteins were used for protein-protein docking. The docked protein-protein complex was minimized by Schrodinger software using OPLS_2005 force field. The binding site of the minimized Wzb-Wzc complex was identified by Sitemap. The high throughput virtual screening identified Labetalol hydrochloride and 4-{1-hydroxy-2-[(1-methyl-3-phenylpropyl) amino] propyl} phenol from FDA-approved drug library based on their interaction at the interface of Wzb-Wzc complex. The inhibitor-protein complex was further undergone molecular mechanics analysis using Generalized Born model and Solvent Accessibility (MMGBSA) to estimate the binding free energies. The lead was also used to generate the pharmacophore model and screening the molecule with antimicrobial scaffold. The identified lead was experimentally validated for its effect on EPS quantity and biofilm formation by A. baumannii. Wzb-Wzc interaction is essential for biofilm and EPS export; hence, the identified lead might be useful to regulate the biofilm formation by A. baumannii.}, } @article {pmid32399218, year = {2020}, author = {Ramazanpour Esfahani, A and Batelaan, O and Hutson, JL and Fallowfield, HJ}, title = {Role of biofilm on virus inactivation in limestone aquifers: implications for managed aquifer recharge.}, journal = {Journal of environmental health science & engineering}, volume = {18}, number = {1}, pages = {21-34}, pmid = {32399218}, issn = {2052-336X}, abstract = {BACKGROUND: Virus, as nano-sized microorganisms are prevalent in aquifers, which threaten groundwater quality and human health wellbeing. Virus inactivation by attachment onto the limestone surfaces is a determining factor in the transport and retention behavior of virus in carbonaceous aquifers.

METHODS: In the present study, the inactivation of MS2 -as a model virus- by attachment onto the surfaces of limestone grains was investigated in a series of batch experiments under different conditions such as limestone particle size distribution (0.25-0.50, 0.5-1 and 1-2 mm), treated wastewater and RO water, temperature (4 and 22 °C), initial MS2 concentrations (10[3]-10[7] PFU/mL) and static and dynamic conditions. The experimental data of MS2 inactivation was also fitted to a non-linear kinetic model with shoulder and tailing. The characteristics of biofilm on the surfaces of limestone aquifer materials were assessed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).

RESULTS: The inactivation rate of virus decreased with increasing the adsorbent diameter. Furthermore, virus inactivation was greater at room temperature (22 °C) than 4 °C, in both static and dynamic conditions. The inactivation of virus via attachment onto the limestone aquifer materials in dynamic conditions was higher than under static conditions. In addition, fitting the experimental data with a kinetic model showed that virus inactivation was high at higher temperature, smaller limestone grains and dynamic conditions. Moreover, the experiments with treated wastewater showed that in authentic aqueous media, the virus inactivation was considerably higher than in RO water, due to the presence of either monovalent or divalent cations and surface roughness created by biofilms.

CONCLUSION: Finally, in terms of managed aquifer recharge systems, the presence of biofilm increases bacteria and virus retention onto the aquifer surfaces. Graphical abstract.}, } @article {pmid32397430, year = {2020}, author = {Castillo Pedraza, MC and de Oliveira Fratucelli, ED and Ribeiro, SM and Florez Salamanca, EJ and da Silva Colin, J and Klein, MI}, title = {Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {9}, pages = {}, pmid = {32397430}, issn = {1420-3049}, support = {FAPESP #2014/05423-0, #2017/00753-0, #2017/07408-6, #2017/26623-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; #311707/2016-5, #PIBIC41910//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; #405, #443//PROPe-UNESP/ ; }, mesh = {Administration, Topical ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Dental Caries/microbiology/prevention & control ; Drug Synergism ; Flavonoids/*pharmacology ; Fluorides/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Lipopolysaccharides/antagonists & inhibitors/metabolism ; Models, Biological ; Polysaccharides, Bacterial/antagonists & inhibitors/metabolism ; Saliva/chemistry/drug effects/*microbiology ; Small Molecule Libraries/*pharmacology ; Streptococcus mutans/drug effects/genetics/*growth & development ; Teichoic Acids/antagonists & inhibitors/metabolism ; }, abstract = {Dental caries is a diet-biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.}, } @article {pmid32397205, year = {2020}, author = {Vollaro, A and Esposito, A and Esposito, EP and Zarrilli, R and Guaragna, A and De Gregorio, E}, title = {PYED-1 Inhibits Biofilm Formation and Disrupts the Preformed Biofilm of Staphylococcus aureus.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32397205}, issn = {2079-6382}, support = {PRIN2017 (Grant 2017SFBFER to RZ)//Ministero dell'Istruzione, dell'Università e della Ricerca/International ; }, abstract = {Pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1 (PYED-1), a heterocyclic corticosteroid derivative of deflazacort, exhibits broad-spectrum antibacterial activity against Gram-negative and Gram-positive bacteria. Here, we investigated the effect of PYED-1 on the biofilms of Staphylococcus aureus, an etiological agent of biofilm-based chronic infections such as osteomyelitis, indwelling medical device infections, periodontitis, chronic wound infections, and endocarditis. PYED-1 caused a strong reduction in biofilm formation in a concentration dependent manner. Furthermore, it was also able to completely remove the preformed biofilm. Transcriptional analysis performed on the established biofilm revealed that PYED-1 downregulates the expression of genes related to quorum sensing (agrA, RNAIII, hld, psm, and sarA), surface proteins (clfB and fnbB), secreted toxins (hla, hlb, and lukD), and capsular polysaccharides (capC). The expression of genes that encode two main global regulators, sigB and saeR, was also significantly inhibited after treatment with PYED-1. In conclusion, PYED-1 not only effectively inhibited biofilm formation, but also eradicated preformed biofilms of S. aureus, modulating the expression of genes related to quorum sensing, surface and secreted proteins, and capsular polysaccharides. These results indicated that PYED-1 may have great potential as an effective antibiofilm agent to prevent S. aureus biofilm-associated infections.}, } @article {pmid32396007, year = {2020}, author = {Zhang, L and Chichlowski, M and Gross, G and Holle, MJ and Lbarra-Sánchez, LA and Wang, S and Miller, MJ}, title = {Milk Fat Globule Membrane Protects Lactobacillus rhamnosus GG from Bile Stress by Regulating Exopolysaccharide Production and Biofilm Formation.}, journal = {Journal of agricultural and food chemistry}, volume = {68}, number = {24}, pages = {6646-6655}, doi = {10.1021/acs.jafc.0c02267}, pmid = {32396007}, issn = {1520-5118}, mesh = {Animals ; Bile Acids and Salts/*pharmacology ; *Biofilms ; Glycolipids/*chemistry ; Glycoproteins/*chemistry ; Lacticaseibacillus rhamnosus/drug effects/genetics/growth & development/*physiology ; Lipid Droplets/*chemistry ; Mice ; Mice, Inbred BALB C ; Microbial Viability ; Polysaccharides, Bacterial/*metabolism ; Probiotics/*chemistry ; Swine ; }, abstract = {The milk fat globule membrane (MFGM) is a complex, highly conserved structure surrounding fat droplets secreted into mammalian milk. This study evaluated the impact of MFGM on Lactobacillus rhamnosus GG (LGG). MFGM-10 (2.5 g/L, 5 g/L, and 10 g/L) did not affect LGG growth in MRS medium but enhanced the ability of LGG to survive in the presence of 0.5% porcine bile. In the presence of MFGM-10 (5 g/L) and bile (0.5%), there were less complex polysaccharides in the media and less capsular polysaccharides associated with the LGG cells compared to the bile exposure alone (p < 0.05). The expression of four EPS genes was modulated by bile stress and MFGM. Biofilm thickness was increased (p < 0.05) during bile stress with MFGM compared to other treatments. Furthermore, MFGM increased LGG survival during transit in the murine GI tract. Future experiments will determine the impact of MFGM on LGG probiotic functionality.}, } @article {pmid32394240, year = {2020}, author = {Abu El-Wafa, WM and Ahmed, RH and Ramadan, MA}, title = {Synergistic effects of pomegranate and rosemary extracts in combination with antibiotics against antibiotic resistance and biofilm formation of Pseudomonas aeruginosa.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {3}, pages = {1079-1092}, pmid = {32394240}, issn = {1678-4405}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; *Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Drug Therapy, Combination ; Humans ; Microbial Sensitivity Tests ; Phylogeny ; Plant Extracts/*pharmacology ; Pomegranate/*chemistry ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/isolation & purification/physiology ; Rosmarinus/*chemistry ; }, abstract = {The combination of plant extract and antibiotic represents a template for developing of antibiofilm drugs. This study investigated the synergistic effects of pomegranate/rosemary/antibiotic combinations against antibiotic resistance and biofilm formation of Pseudomonas aeruginosa. The results showed that 17 (85%) of total P. aeruginosa isolates were biofilm producers; however, 5 (25%) isolates were demonstrated as a strong biofilm producer. The highest MIC level (1024 μg/ml) of tested antibiotics against strong biofilm producer isolates was observed with piperacillin, however the MIC ranges of ceftazidime, gentamycin, imipenem, and levofloxacin against these isolates were reached to (256-1024 μg/ml), (32-1024 μg/ml), (8-1024 μg/ml), and (8-512 μg/ml), respectively. PS-1 was the representative isolate for strong biofilm formation and high antibiotic resistance. 16S rRNA gene analysis suggested that PS-1 (accession No. MN619678) was identified as a strain of P. aeruginosa POA1. Pomegranate and rosemary extracts were the most effective extracts in biofilm inhibition, which significantly inhibited 91.93 and 90.83% of PS-1 biofilm, respectively. Notably, the synergism between both plant extracts and antibiotics has significantly reduced the MICs of used antibiotics at the level lower than the susceptibility breakpoints. Pomegranate/rosemary/antibiotic combinations achieved the highest biofilm eradication, which ranging from 90.0 to 99.6%, followed by the eradication ranges of pomegranate/rosemary combination, rosemary, and pomegranate extracts, which reached to (76.5-85.4%), (53.1-73.7%), and (41.2-71.5%), respectively. The findings suggest that pomegranate/rosemary/antibiotic combinations may be an effective therapeutic agent for antibiotic resistance and biofilm formation of P. aeruginosa.}, } @article {pmid32394095, year = {2020}, author = {Tsukatani, T and Sakata, F and Kuroda, R and Akao, T}, title = {Biofilm Eradication Activity of Herb and Spice Extracts Alone and in Combination Against Oral and Food-Borne Pathogenic Bacteria.}, journal = {Current microbiology}, volume = {77}, number = {9}, pages = {2486-2495}, doi = {10.1007/s00284-020-02017-z}, pmid = {32394095}, issn = {1432-0991}, support = {224//Yamazaki Spice Promotion Foundation/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Plant Extracts/pharmacology ; *Spices ; *Syzygium ; }, abstract = {The purpose of this study was to select herbs and spices with potent biofilm eradication activities. Further, the combined effects of herb and spice extracts against pathogenic biofilms were evaluated. The biofilm eradication activities of ethanol extracts of 104 herbs and spices were measured by combining a colorimetric microbial viability assay with a biofilm formation technique. Ethanol extract of clove had potent biofilm eradication activities against Escherichia coli, Porphyromonas gingivalis, and Streptococcus mutans. Ethanol extracts of eucalyptus and rosemary had potent biofilm eradication activities against P. gingivalis, Staphylococcus aureus and S. mutans. The combination of extracts of clove with eucalyptus or rosemary showed synergistic or additive effects, or both, on biofilm eradication activities. The main biofilm inhibitors in the ethanol extracts of clove, eucalyptus and rosemary were eugenol, macrocarpals and carnosic acid, respectively. The combinations of extracts of clove with eucalyptus or rosemary had potent biofilm eradication activities against oral and food-borne pathogenic bacteria. The findings of the present study reveal that specific combinations of herb and spice extracts may prevent and control biofilm-related oral diseases, food spoilage, and food poisoning.}, } @article {pmid32393519, year = {2020}, author = {Kimura, T and Kobayashi, K}, title = {Role of Glutamate Synthase in Biofilm Formation by Bacillus subtilis.}, journal = {Journal of bacteriology}, volume = {202}, number = {14}, pages = {}, pmid = {32393519}, issn = {1098-5530}, mesh = {Bacillus subtilis/*enzymology/genetics/*physiology ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Citric Acid/metabolism ; Citric Acid Cycle ; Gene Expression Regulation, Bacterial ; Glutamate Synthase/genetics/*metabolism ; Mutation ; Operon ; }, abstract = {Bacillus subtilis forms robust biofilms in the presence of large amounts of carbon sources, such as glycerol. However, little is known about the importance of the metabolic systems, or the relationship between metabolic systems and regulatory systems, involved in biofilm formation. Glutamate synthase, encoded by gltAB, is an enzyme that converts 2-ketoglutarate (a tricarboxylic acid [TCA] cycle intermediate) and glutamine into glutamate, which is a general amino group donor in metabolism. Here, we show that a ΔgltA mutant exhibited early arrest of biofilm formation in complex medium containing glycerol. This phenotype was not due to glutamate auxotrophy. Consistent with its biofilm formation phenotype, the ΔgltA mutant exhibited an early decrease in expression of the epsA and tapA operons, which are responsible for production of biofilm matrix polymers. This resulted from decreased activity of their regulator, Spo0A, as evidenced by reduced expression of other Spo0A-regulated genes in the ΔgltA mutant. The ΔgltA mutation prevented biofilm formation only in the presence of large amounts of glycerol. Moreover, limited expression of citrate synthase (but not other TCA enzymes) restored biofilm-forming ability to the ΔgltA mutant. These results indicate that the ΔgltA mutant accumulates an inhibitory intermediate (citrate) in the TCA cycle in the presence of large amounts of glycerol. The ΔgltA mutant formed biofilms when excess iron was added to the medium. Taken together, the data suggest that accumulation of citrate ions by the ΔgltA mutant causes iron shortage due to chelation, which prevents activation of Spo0A and causes defective biofilm formation.IMPORTANCEBacillus subtilis, a model organism for bacterial biofilm formation, forms robust biofilms in a medium-dependent manner. Although the regulatory network that controls biofilm formation has been well studied, the importance of the underlying metabolic systems remains to be elucidated. The present study demonstrates that a metabolic disorder in a well-conserved metabolic system causes accumulation of an inhibitory metabolic intermediate that prevents activation of the system that regulates biofilm formation. These findings increase our understanding of the coordination between cellular metabolic status and the regulatory networks governing biofilm formation.}, } @article {pmid32392736, year = {2020}, author = {Brück, HL and Coutte, F and Dhulster, P and Gofflot, S and Jacques, P and Delvigne, F}, title = {Growth Dynamics of Bacterial Populations in a Two-Compartment Biofilm Bioreactor Designed for Continuous Surfactin Biosynthesis.}, journal = {Microorganisms}, volume = {8}, number = {5}, pages = {}, pmid = {32392736}, issn = {2076-2607}, abstract = {Biofilm bioreactors are promising systems for continuous biosurfactant production since they provide process stability through cell immobilization and avoid foam formation. In this work, a two-compartment biofilm bioreactor was designed consisting of a stirred tank reactor and a trickle-bed reactor containing a structured metal packing for biofilm formation. A strong and poor biofilm forming B. subtilis 168 strain due to restored exopolysaccharides (EPS) production or not were cultivated in the system to study the growth behavior of the planktonic and biofilm population for the establishment of a growth model. A high dilution rate was used in order to promote biofilm formation on the packing and wash out unwanted planktonic cells. Biofilm development kinetics on the packing were assessed through a total organic carbon mass balance. The EPS[+] strain showed a significantly improved performance in terms of adhesion capacity and surfactin production. The mean surfactin productivity of the EPS[+] strain was about 37% higher during the continuous cultivation compared to the EPS[-] strain. The substrate consumption together with the planktonic cell and biofilm development were properly predicted by the model (α = 0.05). The results show the efficiency of the biofilm bioreactor for continuous surfactin production using an EPS producing strain.}, } @article {pmid32392720, year = {2020}, author = {Tse, MCC and Cheung, GSP}, title = {Spatial Cleaning Action of Ultrasonic Irrigation on Enterococcus faecalis Biofilm.}, journal = {Dentistry journal}, volume = {8}, number = {2}, pages = {}, pmid = {32392720}, issn = {2304-6767}, abstract = {This study aimed to examine the spatial cleaning effect of ultrasonic irrigation in simulated root canal with oblong cross section in the absence of antimicrobial agent. A 7-day E. faecalis biofilm was cultivated in a rectangular, simulated canal model and subjected to passive ultrasonic irrigation (PUI) with sterile saline for 5 minutes. After that, the biofilm was examined by confocal microscopy after bacterial viability staining at 58 sites around and beyond the endosonic file. Results showed that, at the vicinity of the file, the amount of viable bacteria ranged from 13.1% (2.75 mm from the tip) to 40.5% (4.5 mm level). Lesser amounts of live bacteria were observed within 1 mm from the vibrating file, which amount increased for sites farther away. At 3 mm distance, the amount of bacteria (35.5 to 64.4%) was significantly greater than areas situated close to the vibrating file (P < 0.01). Sites next to the anti-nodes of file had less bacteria remaining than sites near the nodes (P = 0.050). Apically (0.5 mm or more), the amount of bacteria was significantly greater than that at the file tip (16.4%) (P < 0.05). It was concluded that PUI is able to dislodge a single-species biofilm, provided that they are situated in close vicinity to the vibrating file.}, } @article {pmid32392236, year = {2020}, author = {Kriem, LS and Wright, K and Ccahuana-Vasquez, RA and Rupp, S}, title = {Confocal Raman microscopy to identify bacteria in oral subgingival biofilm models.}, journal = {PloS one}, volume = {15}, number = {5}, pages = {e0232912}, pmid = {32392236}, issn = {1932-6203}, mesh = {Actinomyces ; Bacteria/*isolation & purification ; Bacteriological Techniques/methods ; Biofilms/growth & development ; Culture Media ; Fusobacterium nucleatum ; Gingiva/microbiology ; Gingivitis/*microbiology ; Microbial Viability ; Microbiota ; Microscopy, Confocal/methods ; Nonlinear Optical Microscopy/*methods ; Periodontitis/*microbiology ; Plankton ; Prevotella intermedia ; Streptococcus mutans ; Veillonella ; }, abstract = {The study of oral disease progression, in relation to the accumulation of subgingival biofilm in gingivitis and periodontitis is limited, due to either the ability to monitor plaque in vitro. When compared, optical spectroscopic techniques offer advantages over traditional destructive or biofilm staining approaches, making it a suitable alternative for the analysis and continued development of three-dimensional structures. In this work, we have developed a confocal Raman spectroscopy analysis approach towards in vitro subgingival plaque models. The main objective of this study was to develop a method for differentiating multiple oral subgingival bacterial species in planktonic and biofilm conditions, using confocal Raman microscopy. Five common subgingival bacteria (Fusobacterium nucleatum, Streptococcus mutans, Veillonella dispar, Actinomyces naeslundii and Prevotella nigrescens) were used and differentiated using a 2-way orthogonal Partial Least Square with Discriminant Analysis (O2PLS-DA) for the collected spectral data. In addition to planktonic growth, mono-species biofilms cultured using the 'Zürich Model' were also analyzed. The developed method was successfully used to predict planktonic and mono-species biofilm species in a cross validation setup. The results show differences in the presence and absence of chemical bands within the Raman spectra. The O2PLS-DA model was able to successfully predict 100% of all tested planktonic samples and 90% of all mono-species biofilm samples. Using this approach we have shown that Confocal Raman microscopy can analyse and predict the identity of planktonic and mono-species biofilm species, thus enabling its potential as a technique to map oral multi-species biofilm models.}, } @article {pmid32392155, year = {2020}, author = {Naradasu, D and Guionet, A and Miran, W and Okamoto, A}, title = {Microbial current production from Streptococcus mutans correlates with biofilm metabolic activity.}, journal = {Biosensors & bioelectronics}, volume = {162}, number = {}, pages = {112236}, doi = {10.1016/j.bios.2020.112236}, pmid = {32392155}, issn = {1873-4235}, mesh = {Anti-Infective Agents, Local/pharmacology ; *Biofilms/drug effects ; *Biosensing Techniques/methods ; Electricity ; Electrodes ; Humans ; Microbial Sensitivity Tests/methods ; Streptococcus mutans/drug effects/*physiology ; Triclosan/pharmacology ; }, abstract = {Once pathogens form a biofilm, they become more tolerant to drugs and quicker to recover from physical removal than planktonic cells. Because such robustness of a biofilm is associated with the active metabolism of its constituent microbes, establishment of a direct assay quantifying biofilm's metabolic activity is important for developing antibiofilm substrates and techniques. Current production capability via extracellular electron transport (EET) was recently found in Gram-positive pathogens, which we hypothesized to correlate with the metabolic activity of their biofilm. Here, we identified current production from the biofilm of oral pathogen Streptococcus mutans that enables the electrochemical assessments of their metabolic activity in situ which conventionally require gene insertion for a fluorescent protein expression. Single-potential amperometry (SA) showed that S. mutans produced an anodic current and formed a biofilm within 8 h on a +0.4 V electrode vs a standard hydrogen electrode (SHE) in the presence of the electron donor glucose. Current production was significantly decreased by the addition of a metabolic inhibitor Triclosan. Furthermore, the anabolic activity of a single cell using high-resolution mass spectroscopy revealed that higher current production resulted in a higher metabolic fixation of an atomically labeled nitrogen [15]N. These results demonstrate that current production in S. mutans reflects its metabolic activity. Given electrochemical impedance spectroscopy (EIS) helps quantifying the bacterial cell adhesion on the electrode, combination of EIS and SA could be a novel assay for EET capable pathogens for quantifying their time-dependent metabolic activity, cellular electrode coverage and physiological response to antibiofilm compounds.}, } @article {pmid32391052, year = {2020}, author = {Yadav, MK and Go, YY and Chae, SW and Park, MK and Song, JJ}, title = {Asian Sand Dust Particles Increased Pneumococcal Biofilm Formation in vitro and Colonization in Human Middle Ear Epithelial Cells and Rat Middle Ear Mucosa.}, journal = {Frontiers in genetics}, volume = {11}, number = {}, pages = {323}, pmid = {32391052}, issn = {1664-8021}, abstract = {INTRODUCTION: Air pollutants such as Asian sand dust (ASD) and Streptococcus pneumoniae are risk factors for otitis media (OM). In this study, we evaluate the role of ASD in pneumococcal in vitro biofilm growth and colonization on human middle ear epithelium cells (HMEECs) and rat middle ear using the rat OM model.

METHODS: S. pneumoniae D39 in vitro biofilm growth in the presence of ASD (50-300 μg/ml) was evaluated in metal ion-free BHI medium using CV-microplate assay, colony-forming unit (cfu) counts, resazurin staining, scanning electron microscopy (SEM), and confocal microscopy (CF). Biofilm gene expression analysis was performed using real-time RT-PCR. The effects of ASD or S. pneumoniae individually or on co-treatment on HMEECs were evaluated by detecting HMEEC viability, apoptosis, and reactive oxygen species (ROS) production. In vivo colonization of S. pneumoniae in the presence of ASD was evaluated using the rat OM model, and RNA-Seq was used to evaluate the alterations in gene expression in rat middle ear mucosa.

RESULTS: S. pneumoniae biofilm growth was significantly (P < 0.05) elevated in the presence of ASD. SEM and CF analysis revealed thick and organized pneumococcal biofilms in the presence of ASD (300 μg/ml). However, in the absence of ASD, bacteria were unable to form organized biofilms, the cell size was smaller than normal, and long chain-like structures were formed. Biofilms grown in the presence of ASD showed elevated expression levels of genes involved in biofilm formation (luxS), competence (comA, comB, ciaR), and toxin production (lytA and ply). Prior exposure of HMEECs to ASD, followed by treatment for pneumococci, significantly (P < 0.05) decreased cell viability and increased apoptosis, and ROS production. In vivo experiment results showed significantly (P < 0.05) more than 65% increased bacteria colonization in rat middle ear mucosa in the presence of ASD. The apoptosis, cell death, DNA repair, inflammation and immune response were differentially regulated in three treatments; however, number of genes expressed in co-treatments was higher than single treatment. In co-treatment, antimicrobial protein/peptide-related genes (S100A family, Np4, DEFB family, and RATNP-3B) and OM-related genes (CYLD, SMAD, FBXO11, and CD14) were down regulated, and inflammatory cytokines and interleukins, such as IL1β, and TNF-related gene expression were elevated.

CONCLUSION: ASD presence increased the generation of pneumococcal biofilms and colonization.}, } @article {pmid32390423, year = {2020}, author = {Tan, CH and Oh, HS and Sheraton, VM and Mancini, E and Joachim Loo, SC and Kjelleberg, S and Sloot, PMA and Rice, SA}, title = {Convection and the Extracellular Matrix Dictate Inter- and Intra-Biofilm Quorum Sensing Communication in Environmental Systems.}, journal = {Environmental science & technology}, volume = {54}, number = {11}, pages = {6730-6740}, doi = {10.1021/acs.est.0c00716}, pmid = {32390423}, issn = {1520-5851}, mesh = {Bacteria ; Biofilms ; *Convection ; Extracellular Matrix ; *Quorum Sensing ; }, abstract = {The mechanisms and impact of bacterial quorum sensing (QS) for the coordination of population-level behaviors are well studied under laboratory conditions. However, it is unclear how, in otherwise open environmental systems, QS signals accumulate to sufficient concentration to induce QS phenotypes, especially when quorum quenching (QQ) organisms are also present. We explore the impact of QQ activity on QS signaling in spatially organized biofilms in scenarios that mimic open systems of natural and engineered environments. Using a functionally differentiated biofilm system, we show that the extracellular matrix, local flow, and QQ interact to modulate communication. In still aqueous environments, convection facilitates signal dispersal while the matrix absorbs and relays signals to the cells. This process facilitates inter-biofilm communication even at low extracellular signal concentrations. Within the biofilm, the matrix further regulates the transport of the competing QS and QQ molecules, leading to heterogenous QS behavior. Importantly, only extracellular QQ enzymes can effectively control QS signaling, suggesting that the intracellular QQ enzymes may not have evolved to degrade environmental QS signals for competition.}, } @article {pmid32390104, year = {2020}, author = {Abdelfattah, A and Hossain, MI and Cheng, L}, title = {High-strength wastewater treatment using microbial biofilm reactor: a critical review.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {5}, pages = {75}, doi = {10.1007/s11274-020-02853-y}, pmid = {32390104}, issn = {1573-0972}, mesh = {*Biofilms ; Biomass ; Bioreactors/*microbiology ; Bromates/metabolism ; Carbon/metabolism ; Denitrification ; Industrial Microbiology ; Membranes ; Nitrification ; Nitrogen ; Perchlorates/metabolism ; Sewage/microbiology ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {Biofilm reactors retain microbial cells in the form of biofilm which is attached to free moving or fixed carrying materials, thus providing a high active biomass concentration and automatic liquid and solid separation. Nowadays, microbial biofilm reactors have been widely used in high-strength wastewater treatment where very high pollutant removal efficiency is required, which usually requires excessive space and aeration energy for conventional activated sludge-based treatment. This paper provides an overview of microbial biofilm reactors developed over the last half-century, including moving bed biofilm reactor (MBBR), trickling filter (TF) reactor, rotating biological contactor (RBC), membrane biofilm reactor (MBfR), passive aeration simultaneous nitrification and denitrification (PASND) biofilm reactor, for their applications in high-strength wastewater treatment of not only removing carbon, nitrogen, sulphur but also a variety of oxidized contaminants including perchlorate and bromate. Despite the advance of biofilm reactor that exhibits high resistance to excessive pollutants loading, its drawbacks both from engineering and microbiological point of view are reviewed. The future prospects of biofilm reactor are also discussed in this review paper.}, } @article {pmid32389829, year = {2020}, author = {Crecencio, RB and Brisola, MC and Bitner, D and Frigo, A and Rampazzo, L and Borges, KA and Furian, TQ and Salle, CTP and Moraes, HLS and Faria, GA and Da Silva, AS and Stefani, LM}, title = {Antimicrobial susceptibility, biofilm formation and genetic profiles of Escherichia coli isolated from retail chicken meat.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {84}, number = {}, pages = {104355}, doi = {10.1016/j.meegid.2020.104355}, pmid = {32389829}, issn = {1567-7257}, mesh = {Animals ; Biofilms ; Brazil ; Chickens/*microbiology ; Escherichia coli/*drug effects/*genetics/isolation & purification ; Food Microbiology ; Microbial Sensitivity Tests/methods ; Poultry Products/microbiology ; beta-Lactamases/genetics ; }, abstract = {Brazil is the number one exporter of chicken meat, and this industry maintains constant microbiological vigilance. The objective of this study was to characterize the pathogenicity, antimicrobial resistance (AMR) and the profile of biofilm production of Escherchia coli strains isolated from raw refrigerated cuts of chicken meat sold in retail markets of the four largest poultry companies in Brazil. We collected 150 samples of chicken meat, in order to isolate E. coli and performed susceptibility tests (to amoxicillin associated with clavulanic acid, ceftiofur, enrofloxacin, gentamicin, and trimethoprim + sulfamethoxazole). In addition, the disc approximation test to detect extended spectrum beta-lactamases enzymes (ESBLs) producers was performed. E. coli ability to form biofilm was checked using polystyrene microplates. We also searched for ESBLs genes (blaCTY-M2, blaSHV-1, blaTEM-1, blaCTX-M2, blaOXA-1, blaPSE-1 and AmpC) and adhesion genes (sfa/foc, afa/draB, iha, hrla, fimC, tsh, papC, mat, cr1, felA, fimH and papG) in ESBL-E. coli producers and in those E. coli classified as strongly biofilm formers, respectively. The overall percentage of E. coli isolation was 58.66%, with brand A having the highest percentage (70%), followed by brands D, B and C (60, 53.3 and 50%, respectively). The highest resistance profile was observed for beta-lactams (39.5%), followed by sulfonamide associated to trimethoprim (36.9%) and polymyxin (33.4%). Of the isolates obtained, 77% were non-susceptible to at least one antimicrobial. Brand A showed the highest overall percentage of resistance with 95.23%, followed by brands C (80%), B (75%) and D (69.44%). Overall, 73.86% of the isolates were non susceptible to at least one antibiotic and 36.3% were multiresistants. A total of 17.04% of E. coli strains were identified as ESBLs producers and 70.44% were able to form biofilms (moderate-to-strong). The blaTEM-1 gene was the most prevalent (73.33%), followed by blaSHV-1 (46.66%) and blaCMY-2 (6%). Of the 31 strongly biofilm-forming strains, 26 (83.87%), 24 (77.41%) and 20 (64.51%) expressed fimC, papG and crl genes, respectively. Taken together, our results show that Brazilian chicken meat can be contaminated with E. coli that are non-susceptible to multiple antibiotics, able to form biofilm and showing a diverse repertoire of adhesins linked to pathogenicity depending on the brand evaluated.}, } @article {pmid32389294, year = {2020}, author = {Martins de Andrade, V and Bardají, E and Heras, M and Ramu, VG and Junqueira, JC and Diane Dos Santos, J and Castanho, MARB and Conceição, K}, title = {Antifungal and anti-biofilm activity of designed derivatives from kyotorphin.}, journal = {Fungal biology}, volume = {124}, number = {5}, pages = {316-326}, doi = {10.1016/j.funbio.2019.12.002}, pmid = {32389294}, issn = {1878-6146}, mesh = {Animals ; *Antifungal Agents/pharmacology ; *Biofilms/drug effects ; *Candida/drug effects ; Drug Resistance/drug effects ; *Endorphins/chemistry/pharmacology ; Larva/microbiology ; Microbial Sensitivity Tests ; Moths/microbiology ; }, abstract = {Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous analgesic neuropeptide first isolated from bovine brain in 1979. Previous studies have shown that kyotorphins possess anti-inflammatory and antimicrobial activity. Six kyotorphins-KTP-NH2, KTP-NH2-DL, ibuprofen-conjugated KTP (IbKTP), IbKTP-NH2, N-methyl-D-Tyr-L-Arg, and N-methyl-L-Tyr-D-Arg-were designed and synthesized to improve lipophilicity and resistance to enzymatic degradation. This study assessed the antimicrobial and antibiofilm activity of these peptides. The antifungal activity of kyotorphins was determined in representative strains of Candida species, including Candida albicans ATCC 10231, Candida krusei ATCC 6258, and six clinical isolates-Candida dubliniensis 19-S, Candida glabrata 217-S, Candida lusitaniae 14-S, Candida novergensis 51-S, Candida parapsilosis 63, and Candida tropicalis 140-S-obtained from the oral cavity of HIV-positive patients. The peptides were synthesized by standard solution or solid-phase synthesis, purified by RP-HPLC (purity >95 %), and characterized by nuclear magnetic resonance. The results of the broth microdilution assay and scanning electron microscopy showed that IbKTP-NH2 presented significant antifungal activity against Candida strains and antibiofilm activity against the clinical isolates. The absence of toxic activity and survival after infection was assessed after injecting the peptide in larvae of Galleria mellonella as experimental infection model. Furthermore, IbKTP-NH2 had strong antimicrobial activity against multidrug-resistant bacteria and fungi and was not toxic to G. mellonella larvae up to a concentration of 500 mM. These results suggest that IbKTP-NH2, in addition to its known effect on cell membranes, can elicit a cellular immune response and, therefore, is promising for biomedical application.}, } @article {pmid32388374, year = {2020}, author = {Zhang, X and Wang, C and Wu, P and Yin, W and Xu, L}, title = {New insights on biological nutrient removal by coupling biofilm-based CANON and denitrifying phosphorus removal (CANDPR) process: Long-term stability assessment and microbial community evolution.}, journal = {The Science of the total environment}, volume = {730}, number = {}, pages = {138952}, doi = {10.1016/j.scitotenv.2020.138952}, pmid = {32388374}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors ; Denitrification ; *Microbiota ; Nitrogen ; Nutrients ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {It was difficult to obtain a stable and efficient biological nutrient removal for high-strength wastewater treatment, the possibility of exploiting innovative CANDPR process, integrating biofilm-based completely autotrophic nitrogen removal over nitrite (CANON) with denitrifying phosphorus removal (DPR) was evaluated to resolve the difficulty. Results revealed that the excellent NH4[+]-N, PO4[3-]-P and COD removal efficiencies of 96%, 96% and 91%, were achieved respectively under a high nitrogen loading rate (0.79 kg·m[-3]·d[-1]) without adding organic matters during 320 days operation. Promoting NOx[-]-N recirculation demonstrated as an efficient strategy for further nutrient depletion, facilitating the enhanced NO3[-]-N removal to 100% with the considerably high P-uptake performance. Batch tests confirmed that denitrifying phosphorus accumulating organisms (DPAOs) using NO3[-]-N as electron acceptors accounting for 68% in total PAOs. Dechloromonas was identified as dominating genus in DPR, while Nitrosomonas (1.31%), Candidatus_Kuenenia (5.53%) and Candidatus_Brocadia (1.77%) contributed to the desirable nitrogen removal, indicating that cooperative consortia of DPAOs, AOB and AnAOB were harvested during long-term operation. The CANDPR process was verified to be energy-saving and treatment-reliable for renovating of existing plants.}, } @article {pmid32388030, year = {2020}, author = {Recupido, F and Toscano, G and Tatè, R and Petala, M and Caserta, S and Karapantsios, TD and Guido, S}, title = {The role of flow in bacterial biofilm morphology and wetting properties.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {192}, number = {}, pages = {111047}, doi = {10.1016/j.colsurfb.2020.111047}, pmid = {32388030}, issn = {1873-4367}, abstract = {Biofilms are bacterial communities embedded in an extracellular matrix, able to adhere to surfaces. Different experimental set-ups are widely used for in vitro biofilm cultivation; however, a well-defined comparison among different culture conditions, especially suited to interfacial characterization, is still lacking in the literature. The main objective of this work is to study the role of flow on biofilm formation, morphology and interfacial properties. Three different in vitro setups, corresponding to stagnant, shaking, and laminar flow conditions (custom-made flow cell), are used in this work to grow single strain biofilms of Pseudomonas fluorescens AR 11 on glass coupons. Results show that flow conditions significantly influenced biofilm formation kinetics, affecting mass transfer and cell attachment/detachment processes. Distinct morphological patterns are found under different flow regimes. Static contact angle data do not depend significantly on biofilm growth conditions in the parametric range investigated in this work.}, } @article {pmid32387904, year = {2020}, author = {Jiang, L and Wu, A and Fang, D and Zhang, Y and Shen, Q and Xu, X and Ji, F}, title = {Denitrification performance and microbial diversity using starch-polycaprolactone blends as external solid carbon source and biofilm carriers for advanced treatment.}, journal = {Chemosphere}, volume = {255}, number = {}, pages = {126901}, doi = {10.1016/j.chemosphere.2020.126901}, pmid = {32387904}, issn = {1879-1298}, mesh = {Biofilms ; Bioreactors/microbiology ; Carbon/chemistry ; Comamonadaceae ; Denitrification ; Nitrates/chemistry ; Nitrogen/chemistry ; Polyesters/*chemistry ; Starch/chemistry ; Temperature ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; }, abstract = {Enhanced nitrate removal from the secondary effluent in municipal wastewater treatment plants (WWTPs) is essential for avoiding water eutrophication. To this end, a vertical baffled solid-phase denitrification reactor (VBSDR) was developed using a starch and polycaprolactone (PCL) blend plate (S-PCL) as a carbon source and biofilm carrier. In this study, we evaluated the denitrification performance and microbial diversity of the VBSDR. The results of the Fourier transform infrared spectroscopy (FTIR), carbon leaching experiment, and scanning electron microscopy (SEM) demonstrated that the S-PCL structure can be attached and degraded more rapidly. Furthermore, the denitrification performance under varied operational conditions, i.e., influent nitrate loading rate (NLR) and operating temperature, was also investigated. Herein, when treating low C/N ratio and low-strength wastewater, a high denitrification rate (DR) [0.33 gN/(L·d)] was achieved. The effect of temperature on DR can be described by the Arrhenius-type equation, which shows that low temperature has a negative influence on DR and nitrate removal efficiency. Furthermore, DR was simultaneously affected by the NLR and temperature. The microbial diversity and community structure were determined by Illumina high-throughput sequencing. The special carbon source led to Acidovorax (denitrifying bacteria) and Flavobacterium (hydrolysis acidifying bacteria) being the VBSDR biofilm's most predominant functional bacteria at the genus level.}, } @article {pmid32387459, year = {2020}, author = {Bohm, GC and Gándara, L and Di Venosa, G and Mamone, L and Buzzola, F and Casas, A}, title = {Photodynamic inactivation mediated by 5-aminolevulinic acid of bacteria in planktonic and biofilm forms.}, journal = {Biochemical pharmacology}, volume = {177}, number = {}, pages = {114016}, doi = {10.1016/j.bcp.2020.114016}, pmid = {32387459}, issn = {1873-2968}, mesh = {Aminolevulinic Acid/metabolism/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Gram-Negative Bacteria/*drug effects/physiology ; Gram-Positive Bacteria/*drug effects/physiology ; Light ; Photochemotherapy/*methods ; Photosensitizing Agents/metabolism/*pharmacology ; Plankton/microbiology ; Porphyrins/analysis/metabolism ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus ; Staphylococcus epidermidis/drug effects/physiology ; Time Factors ; }, abstract = {Bacterial photodynamic inactivation (PDI) employing endogenous production of porphyrins from 5-aminolevulinic acid (ALA) - named ALA-PDI-, is a new promising tool to achieve bacteria control in non-spread infections. The technique combines the action of the porphyrins acting as photosensitisers with light, to produce reactive oxygen species to target the pathogen. To date, some clinical applications of ALA-PDI have been reported although variable responses ranging from total eradication to absence of photokilling were found. ALA-PDI conducted at suboptimal conditions may lead to misleading results and the complexity of haem synthesis in bacteria hinders the optimization of the treatment. The present work aimed to gain insight on the variables affecting ALA-PDI in Gram-positives and Gram-negatives bacteria growing on planktonic and biofilm cultures and to correlate the degree of the response with the amount and type of porphyrin synthesised. Staphylococcus epidermidis and Escherichia coli clinical isolates and Pseudomonas aeruginosa ATCC27853 and Staphylococcus aureus ATCC25923 strains were utilised, and the optimal conditions of concentration and time exposure of ALA, and light dose were set. In both Gram-positive species analysed, a peak of porphyrin synthesis was observed at 1-2 mM ALA in biofilm and planktonic cultures, which fairly correlated with the decrease in the number of CFU after PDI (5 to 7 logs) and porphyrin content was in the same order of magnitude. In addition, ALA-PDI was similarly effective for planktonic and biofilm S. aureus cultures, and more effective in S. epidermidis planktonic cultures at low light doses. Beyond a certain light dose, it was not possible to achieve further photosensitization. Similarly, a plateau of cell death was attained at a certain ALA incubation time. Accumulation of hydrophilic porphyrins at longer incubation periods was observed. The proportion of porphyrins changed as a function of ALA concentration and incubation time in the Gram-positive bacteria, though we did not find a clear correlation between the porphyrin type and PDI response. As a salient feature was the presence of isococroporphyrin isoforms in both Gram-positive and Gram-negative bacteria. Gram-negative bacteria were quite refractory to the treatment: P. aeruginosa was slightly inactivated (4-logs reduction) at 40 mM ALA, whereas E. coli was not inactivated at all. These species accumulated high ALA quantities and the amount of porphyrins did not correlate with the degree of photoinactivation. Our microscopy studies show that porphyrins are not located in the envelopes of Gram-negative bacteria, reinforcing the hypothesis that endogenous porphyrins fail to attack these structures.}, } @article {pmid32384621, year = {2020}, author = {Azzola, F and Ionescu, AC and Ottobelli, M and Cavalli, N and Brambilla, E and Corbella, S and Francetti, L}, title = {Biofilm Formation on Dental Implant Surface Treated by Implantoplasty: An In Situ Study.}, journal = {Dentistry journal}, volume = {8}, number = {2}, pages = {}, pmid = {32384621}, issn = {2304-6767}, abstract = {Peri-implantitis is a biofilm-related disease whose characteristics are peri-implant tissues inflammation and bone resorption. Some clinical trials report beneficial effects after implantoplasty, namely the surgical smoothening of the implant surface, but there is a lack of data about the development of the bacterial biofilm on those smoothened surfaces. The aim of this study is to evaluate how implantoplasty influences biofilm formation. Three implants with moderately rough surfaces (control) and three implants treated with implantoplasty (test) were set on a tray reproducing the supra- and sub-gingival environment. One volunteer wore this tray for five days. Every 24 h, plaque coverage was measured and, at the end of the period of observartion, the implant surfaces were analyzed using scanning electron microscopy and confocal laser scanning microscopy. The proportion of implant surface covered with plaque was 65% (SD = 7.07) of the control implants and 16% (SD = 0) of the test implants. Untreated surfaces showed mature, complex biofilm structures with wide morphological diversity, and treated surfaces did not show the formation of mature biofilm structures. This study supports the efficacy of implantoplasty in reducing plaque adhesion and influencing biofilm formation. These results can be considered a preliminary proof of concept, but they may encourage further studies about the effects of implantoplasty on biofilm formation.}, } @article {pmid32384241, year = {2020}, author = {Shi, Y and Tian, Z and Gillings, MR and Zhang, Y and Zhang, H and Huyan, J and Yang, M}, title = {Novel Transposon Tn6433 Variants Accelerate the Dissemination of tet(E) in Aeromonas in an Aerobic Biofilm Reactor under Oxytetracycline Stresses.}, journal = {Environmental science & technology}, volume = {54}, number = {11}, pages = {6781-6791}, doi = {10.1021/acs.est.0c01272}, pmid = {32384241}, issn = {1520-5851}, mesh = {*Aeromonas ; Anti-Bacterial Agents ; Biofilms ; Genes, Bacterial ; Integrons ; *Oxytetracycline ; Plasmids/genetics ; }, abstract = {Little is known about the mechanisms that disseminate antibiotic resistance genes (ARGs) in wastewater microbial communities under antibiotic stress. The role of horizontal transfer mechanisms in dissemination of ARGs in an aerobic biofilm reactor under incremental oxytetracycline doses from 0 to 50 mg/L was studied. Aeromonas strains were the most common culturable bacteria in the reactor, with tet(E) as the most prevalent ARGs (73.3%) being possibly responsible for the oxytetracycline resistance phenotype. Genomic sequencing demonstrated that tet(E) was mainly carried by a Tn3 family transposon named Tn6433, whose incidence increased from 14.6% to 75.0% across the treatments. Tn6433 carrying tet(E) was initially detected in Aeromonas chromosomes at an oxytetracycline dose of 1 mg/L but subsequently detected on plasmids pAeca1-a variants (pAeca1-a, pAeca1-b, and pAeme6) and pAeca2 under higher oxytetracycline stress. The core region of the Tn6433-tet(E) structure was highly conserved, consisting of a transposition and resolution module, a class 1 integron, core passenger genes, and a Tn1722/Tn501-like transposon. Such a structure was found on both the chromosome and plasmids, suggesting that Tn6433 mediated the transposition of tet(E) from the chromosome to plasmid pAeca2 under increasing stresses. Bacteria carrying the transferable plasmid pAeca1-a were dominant in high antibiotic treatments, suggesting that Tn6433 disseminated tet(E), conferring selective advantages to recipients of this ARG.}, } @article {pmid32382563, year = {2020}, author = {Siddique, MH and Aslam, B and Imran, M and Ashraf, A and Nadeem, H and Hayat, S and Khurshid, M and Afzal, M and Malik, IR and Shahzad, M and Qureshi, U and Khan, ZUH and Muzammil, S}, title = {Effect of Silver Nanoparticles on Biofilm Formation and EPS Production of Multidrug-Resistant Klebsiella pneumoniae.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {6398165}, pmid = {32382563}, issn = {2314-6141}, mesh = {Biofilms/*drug effects/growth & development ; Drug Resistance, Multiple, Bacterial/*drug effects ; Klebsiella pneumoniae/*physiology ; Metal Nanoparticles/*chemistry ; Silver/chemistry/*pharmacology ; }, abstract = {Antibiotic resistance against present antibiotics is rising at an alarming rate with need for discovery of advanced methods to treat infections caused by resistant pathogens. Silver nanoparticles are known to exhibit satisfactory antibacterial and antibiofilm activity against different pathogens. In the present study, the AgNPs were synthesized chemically and characterized by UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. Antibacterial activity against MDR K. pneumoniae strains was evaluated by agar diffusion and broth microdilution assay. Cellular protein leakage was determined by the Bradford assay. The effect of AgNPs on production on extracellular polymeric substances was evaluated. Biofilm formation was assessed by tube method qualitatively and quantitatively by the microtiter plate assay. The cytotoxic potential of AgNPs on HeLa cell lines was also determined. AgNPs exhibited an MIC of 62.5 and 125 μg/ml, while their MBC is 250 and 500 μg/ml. The production of extracellular polymeric substance decreased after AgNP treatment while cellular protein leakage increased due to higher rates of cellular membrane disruption by AgNPs. The percentage biofilm inhibition was evaluated to be 64% for K. pneumoniae strain MF953600 and 86% for MF953599 at AgNP concentration of 100 μg/ml. AgNPs were evaluated to be minimally cytotoxic and safe at concentrations of 15-120 μg/ml. The data evaluated by this study provided evidence of AgNPs being safe antibacterial and antibiofilm compounds against MDR K. pneumoniae.}, } @article {pmid32381824, year = {2020}, author = {Gómez, C and Salcedo-Moncada, D and Ayala, G and Watanabe, R and Pineda, M and Alvítez-Temoche, D and Mayta-Tovalino, F}, title = {Antimicrobial Efficacy of Calcium and Sodium Hypochlorite at Different Concentrations on a Biofilm of Enterococcus faecalis and Candida albicans: An In Vitro Comparative Study.}, journal = {The journal of contemporary dental practice}, volume = {21}, number = {2}, pages = {178-182}, pmid = {32381824}, issn = {1526-3711}, mesh = {*Anti-Infective Agents ; Biofilms ; Calcium ; Candida albicans ; *Enterococcus faecalis ; Root Canal Irrigants ; Sodium Hypochlorite ; }, abstract = {AIM: To compare the antimicrobial efficacy of sodium hypochlorite (NaClO at 2.5% and 5.25%) and calcium hypochlorite [Ca(ClO)2 at 2.5%] on a biofilm of Enterococcus faecalis ATCC 29212™ and Candida albicans ATCC 10231™.

MATERIALS AND METHODS: We performed an experimental in vitro study. Strains of C. albicans and E. faecalis, which had previously been reactivated were used. Then the colonies to be used were standardized in a turbidity standard to guarantee a quantity of 108 (CFU/mL) using the McFarland scale (0.5). Subsequently, the biofilm formed in brain-heart infusion agar was seeded into 42 sterile disks previously embedded with the experimental substances. Both 2.5% NaClO and Ca(ClO)2 solutions were placed in each Petri dish. They were then incubated at 37°C for 24 hours and the inhibition halos were measured using the Kirby-Bauer technique.

RESULTS: The means between the halos corresponding to NaClO and Ca(ClO)2 at 2.5% were 13.38 ± 0.64 mm and 13.42 ± 0.62 mm, respectively. According to the Tukey test, no statistically significant differences were found between the hypochlorite groups evaluated (p = 0.989).

CONCLUSION: Both Ca(ClO)2 and NaClO have a similar antimicrobial efficacy with biofilm based on E. faecalis and C. albicans, with no statistically significant differences between the two.

CLINICAL SIGNIFICANCE: This study demonstrates the effectiveness of Ca(ClO)2 and NaClO as endodontic irrigators to combat the most frequent microorganisms of the root canal.}, } @article {pmid32380504, year = {2020}, author = {Khamari, B and Lama, M and Pachi Pulusu, C and Biswal, AP and Lingamallu, SM and Mukkirla, BS and Sahoo, AK and Dash, HSN and Sharda, R and Kumar, P and Bulagonda, EP}, title = {Molecular Analyses of Biofilm-Producing Clinical Acinetobacter baumannii Isolates from a South Indian Tertiary Care Hospital.}, journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre}, volume = {29}, number = {6}, pages = {580-587}, pmid = {32380504}, issn = {1423-0151}, mesh = {Acinetobacter baumannii/*genetics/isolation & purification/*physiology ; *Biofilms ; Drug Resistance, Multiple, Bacterial/*genetics ; Humans ; Microbial Sensitivity Tests ; Random Amplified Polymorphic DNA Technique ; Tertiary Care Centers ; Virulence Factors/metabolism ; beta-Lactamases/genetics ; }, abstract = {OBJECTIVES: The aim of the study was to determine the presence of antimicrobial-resistance (AMR) genes, virulence genes, and mobile genetic elements (MGEs) in 14 biofilm-producing clinical isolates of Acinetobacter baumannii.

MATERIALS AND METHODS: PCR amplification was performed to analyse the prevalence of genes associated with antibiotic resistance (extended-spectrum β-lactamases [ESBLs] and metallo-β-lactamases [MBLs]), virulence factors, MGEs (class 1 integron, Tn1213, and A. baumannii antibiotic resistance [AbaR]), and comM among the study isolates. Random amplified polymorphic DNA (RAPD) PCR was then deployed to understand their phylogenetic relationship. All the isolates were investigated for biofilm production.

RESULTS: Two isolates were antibiotic-sensitive (AS), 3 were multi-drug-resistant (MDR), and the remaining 9 were extensively drug-resistant (XDR). The majority of the isolates were found to be positive for biofilm production and were sensitive against tetracycline and colistin only. Ab14 and Ab11 were found to be resistant to minocycline and colistin, respectively. blaTEM, blaOXA, blaNDM, blaVIM, blaSIM, and blaPER-1; class 1 integron; composite transposon Tn1213; AbaR island, and virulence factor genes were detected among the isolates. These pathogens were found to have originated from multiple clonal lineages.

CONCLUSION: Biofilm-producing A. baumannii with multiple virulence and AMR genes pose serious clinical challenges. The presence of MGEs further compounds the situation as these isolates serve as potential reservoirs of AMR and virulence genes. Together with their capacity for natural competence, A. baumannii, if left unchecked, will lead to the spread of resistance determinants to previously sensitive bacteria and may aid in the emergence of untreatable pan-drug-resistant phenotypes.}, } @article {pmid32380254, year = {2020}, author = {Souza Amaral, L and Orzari Ribeiro, A and Rodrigues Perussi, J}, title = {Evidence of hypericin photoinactivation of E. faecalis: From planktonic culture to mammalian cells selectivity up to biofilm disruption.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {31}, number = {}, pages = {101759}, doi = {10.1016/j.pdpdt.2020.101759}, pmid = {32380254}, issn = {1873-1597}, mesh = {Animals ; Anthracenes ; Biofilms ; Enterococcus faecalis ; Perylene/analogs & derivatives ; *Photochemotherapy/methods ; *Photosensitizing Agents/pharmacology ; Plankton ; }, abstract = {Antimicrobial Photodynamic Therapy (aPDT) is an alternative for microbiological inactivation. The aPDT is a method that uses a photosensitizer (PS) excited by visible light at the appropriate wavelength and the molecular oxygen present in the tissues resulting in the production of reactive oxygen species, which causes oxidative damage to biological molecules. This study aimed to perform an in vitro experimental sequence for photoinactivation of E. faecalis using Hypericin (HY) from planktonic culture to selectivity assays using mammalian cells up to biofilm. The results show that E. faecalis rapidly absorb HY. The levels of inactivation of E. faecalis reached up to 99% in planktonic culture. Transmission and Scanning Electron Microscopy demonstrate the remarkable morphological alterations resulting from photooxidation being the loss of membrane integrity assessed by fluorescence microscopy combined with a LIVE/DEAD™ kit. HY did not present cytotoxicity to the fibroblasts cell at the used conditions proving to be a selective molecule. Finally, 60% of photoinactivation was observed in the biofilm of E. faecalis when subject to HY-aPDT. These outcomes show the advantages of sequential in vitro experiments besides showing that HY is a potential PS for clinical trials due to its selectivity and photodynamic effect. This study also draws attention to the benefits of using methodologies that can evidence the antimicrobial effect beyond the typical constellation of cell death.}, } @article {pmid32378822, year = {2020}, author = {Natan, M and Jacobi, G and Banin, E and Ashkenazi, S}, title = {Prevention and Treatment of Pseudomonas Aeruginosa-Based Biofilm with Ethanol.}, journal = {The Israel Medical Association journal : IMAJ}, volume = {22}, number = {5}, pages = {299-302}, pmid = {32378822}, issn = {1565-1088}, mesh = {Anti-Infective Agents, Local/*administration & dosage/pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/prevention & control ; Ethanol/*administration & dosage/pharmacology ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/prevention & control ; Pseudomonas aeruginosa/*drug effects/*physiology ; }, abstract = {BACKGROUND: Although indwelling catheters are increasingly used in modern medicine, they can be a source of microbial contamination and hard-to-treat biofilms, which jeopardize patient lives. At times 70% ethanol is used as a catheter-lock solution due to its bactericidal properties. However, high concentrations of ethanol can result in adverse effects and in malfunction of the catheters.

OBJECTIVES: To determine whether low concentrations of ethanol can prevent and treat biofilms of Pseudomonas aeruginosa.

METHODS: Ethanol was tested at a concentration range of 0.625-80% against laboratory and clinical isolates of P. aeruginosa for various time periods (2-48 hours). The following parameters were evaluated following ethanol exposure: prevention of biofilm formation, reduction of biofilm metabolic activity, and inhibition of biofilm regrowth.

RESULTS: Exposing P. aeruginosa to twofold ethanol gradients demonstrated a significant biofilm inhibition at concentrations as low as 2.5%. Treating pre-formed biofilms of P. aeruginosa with 20% ethanol for 4 hours caused a sharp decay in the metabolic activity of both the laboratory and clinical P. aeruginosa isolates. In addition, treating mature biofilms with 20% ethanol prevented the regrowth of bacteria encased within it.

CONCLUSIONS: Low ethanol concentrations (2.5%) can prevent in vitro biofilm formation of P. aeruginosa. Treatment of previously formed biofilms can be achieved using 20% ethanol, thereby keeping the catheters intact and avoiding complications that can result from high ethanol concentrations.}, } @article {pmid32377640, year = {2020}, author = {Xiu, W and Gan, S and Wen, Q and Qiu, Q and Dai, S and Dong, H and Li, Q and Yuwen, L and Weng, L and Teng, Z and Mou, Y and Wang, L}, title = {Biofilm Microenvironment-Responsive Nanotheranostics for Dual-Mode Imaging and Hypoxia-Relief-Enhanced Photodynamic Therapy of Bacterial Infections.}, journal = {Research (Washington, D.C.)}, volume = {2020}, number = {}, pages = {9426453}, pmid = {32377640}, issn = {2639-5274}, abstract = {The formation of bacterial biofilms closely associates with infectious diseases. Until now, precise diagnosis and effective treatment of bacterial biofilm infections are still in great need. Herein, a novel multifunctional theranostic nanoplatform based on MnO2 nanosheets (MnO2 NSs) has been designed to achieve pH-responsive dual-mode imaging and hypoxia-relief-enhanced antimicrobial photodynamic therapy (aPDT) of bacterial biofilm infections. In this study, MnO2 NSs were modified with bovine serum albumin (BSA) and polyethylene glycol (PEG) and then loaded with chlorin e6 (Ce6) as photosensitizer to form MnO2-BSA/PEG-Ce6 nanosheets (MBP-Ce6 NSs). After being delivered into the bacterial biofilm-infected tissues, the MBP-Ce6 NSs could be decomposed in acidic biofilm microenvironment and release Ce6 with Mn[2+], which subsequently activate both fluorescence (FL) and magnetic resonance (MR) signals for effective dual-mode FL/MR imaging of bacterial biofilm infections. Meanwhile, MnO2 could catalyze the decomposing of H2O2 in biofilm-infected tissues into O2 and relieve the hypoxic condition of biofilm, which significantly enhances the efficacy of aPDT. An in vitro study showed that MBP-Ce6 NSs could significantly reduce the number of methicillin-resistant Staphylococcus aureus (MRSA) in biofilms after 635 nm laser irradiation. Guided by FL/MR imaging, MRSA biofilm-infected mice can be efficiently treated by MBP-Ce6 NSs-based aPDT. Overall, MBP-Ce6 NSs not only possess biofilm microenvironment-responsive dual-mode FL/MR imaging ability but also have significantly enhanced aPDT efficacy by relieving the hypoxia habitat of biofilm, which provides a promising theranostic nanoplatform for bacterial biofilm infections.}, } @article {pmid32374766, year = {2020}, author = {Nikinmaa, S and Alapulli, H and Auvinen, P and Vaara, M and Rantala, J and Kankuri, E and Sorsa, T and Meurman, J and Pätilä, T}, title = {Dual-light photodynamic therapy administered daily provides a sustained antibacterial effect on biofilm and prevents Streptococcus mutans adaptation.}, journal = {PloS one}, volume = {15}, number = {5}, pages = {e0232775}, pmid = {32374766}, issn = {1932-6203}, mesh = {Adaptation, Biological/*drug effects/radiation effects ; Anti-Bacterial Agents/*pharmacology ; Bacterial Load/drug effects/radiation effects ; Biofilms/*drug effects/radiation effects ; Humans ; Indocyanine Green/*pharmacology ; Microbial Viability/drug effects/radiation effects ; Oral Hygiene/methods ; Periodontitis/drug therapy ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Streptococcus mutans/*drug effects/radiation effects ; }, abstract = {Antibacterial photodynamic therapy (aPDT) and antibacterial blue light (aBL) are emerging treatment methods auxiliary to mechanical debridement for periodontitis. APDT provided with near-infrared (NIR) light in conjunction with an indocyanine green (ICG) photosensitizer has shown efficacy in several dental in-office-treatment protocols. In this study, we tested Streptococcus mutans biofilm sensitivity to either aPDT, aBL or their combination dual-light aPDT (simultaneous aPDT and aBL) exposure. Biofilm was cultured by pipetting diluted Streptococcus mutans suspension with growth medium on the bottom of well plates. Either aPDT (810 nm) or aBL (405 nm) or a dual-light aPDT (simultaneous 810 nm aPDT and 405 nm aBL) was applied with an ICG photosensitizer in cases of aPDT or dual-light, while keeping the total given radiant exposure constant at 100 J/cm2. Single-dose light exposures were given after one-day or four-day biofilm incubations. Also, a model of daily treatment was provided by repeating the same light dose daily on four-day and fourteen-day biofilm incubations. Finally, the antibacterial action of the dual-light aPDT with different energy ratios of 810 nm and 405 nm of light were examined on the single-day and four-day biofilm protocols. At the end of each experiment the bacterial viability was assessed by colony-forming unit method. Separate samples were prepared for confocal 3D biofilm imaging. On a one-day biofilm, the dual-light aPDT was significantly more efficient than aBL or aPDT, although all modalities were bactericidal. On a four-day biofilm, a single exposure of aPDT or dual-light aPDT was more efficient than aBL, resulting in a four logarithmic scale reduction in bacterial counts. Surprisingly, when the same amount of aPDT was repeated daily on a four-day or a fourteen-day biofilm, bacterial viability improved significantly. A similar improvement in bacterial viability was observed after repetitive aBL application. This viability improvement was eliminated when dual-light aPDT was applied. By changing the 405 nm to 810 nm radiant exposure ratio in dual-light aPDT, the increase in aBL improved the antibacterial action when the biofilm was older. In conclusion, when aPDT is administered repeatedly to S. mutans biofilm, a single wavelength-based aBL or aPDT leads to a significant biofilm adaptation and increased S. mutans viability. The combined use of aBL light in synchrony with aPDT arrests the adaptation and provides significantly improved and sustained antibacterial efficacy.}, } @article {pmid32373581, year = {2020}, author = {Cho, KH and Tryon, RG and Kim, JH}, title = {Screening for Diguanylate Cyclase (DGC) Inhibitors Mitigating Bacterial Biofilm Formation.}, journal = {Frontiers in chemistry}, volume = {8}, number = {}, pages = {264}, pmid = {32373581}, issn = {2296-2646}, abstract = {The majority of bacteria in the natural environment organize themselves into communal biofilms. Biofilm formation benefits bacteria conferring resistance to harmful molecules (e.g., antibiotics, disinfectants, and host immune factors) and coordinating their gene expression through quorum sensing (QS). A primary signaling molecule promoting bacterial biofilm formation is the universal second messenger cyclic di-GMP. This dinucleotide predominantly controls the gene expression of motility, adhesins, and capsule production to coordinate biofilm formation. Cyclic di-GMP is synthesized by diguanylate cyclases (DGCs) that have a GGDEF domain and is degraded by phosphodiesterases (PDEs) containing either an EAL or an HD-GYP domain. Since high cellular c-di-GMP concentrations are correlated with promoting the ability of bacteria to form biofilms, numerous research endeavors to identify chemicals capable of inhibiting the c-di-GMP synthesis activity of DGCs have been performed in order to inhibit bacterial biofilm formation. This review describes currently identified chemical inhibitors that disturb the activity of DGCs and the methods of screening and assay for their discovery.}, } @article {pmid32373078, year = {2020}, author = {Wang, Y and Gong, S and Dong, X and Li, J and Grenier, D and Yi, L}, title = {In vitro Mixed Biofilm of Streptococcus suis and Actinobacillus pleuropneumoniae Impacts Antibiotic Susceptibility and Modulates Virulence Factor Gene Expression.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {507}, pmid = {32373078}, issn = {1664-302X}, abstract = {Streptococcus suis (S. suis) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) are primary swine pathogens that have been frequently co-isolated from pigs suffering from severe respiratory disease. The purpose of this study was to investigate the biological impacts of the interactions between S. suis and A. pleuropneumoniae. A single- and dual-species culture model was established in vitro via S. suis HA9801 (serotype 2) and A. pleuropneumoniae CVCC265 (serotype 1). The single or mixed biofilms were imaged by confocal laser scanning microscopy. The biomass and viable cells in biofilms were quantified by crystal violet staining and determination of colony-forming units. The antibiotic susceptibility was determined by a microdilution broth method. The differences in gene transcription in pure- or mixed-species biofilms of S. suis and A. pleuropneumoniae was evaluated by quantitative PCR. S. suis and A. pleuropneumoniae formed two-species biofilms when co-cultured in vitro. When co-cultured with S. suis, biofilm formation by A. pleuropneumoniae was significantly increased with the absence of NAD that is necessary for the growth of A. pleuropneumoniae. Moreover, compared with monocultures, the antibiotic resistance of S. suis and A. pleuropneumoniae was both enhanced in the co-culture model. When grown in dual-species biofilms, for A. pleuropneumoniae, genes associated with virulence factors, including exotoxins and adhesins, were significantly upregulated. For S. suis, virulence factor-related genes cps2, gdh, mrp, and sly were highly induced. These results suggest that the interspecies interactions between S. suis and A. pleuropneumoniae may be cooperative under specific conditions and may play an important role in the disease progression and persistent infection.}, } @article {pmid32372498, year = {2020}, author = {Wrobel, A and Saragliadis, A and Pérez-Ortega, J and Sittman, C and Göttig, S and Liskiewicz, K and Spence, MH and Schneider, K and Leo, JC and Arenas, J and Linke, D}, title = {The inverse autotransporters of Yersinia ruckeri, YrInv and YrIlm, contribute to biofilm formation and virulence.}, journal = {Environmental microbiology}, volume = {22}, number = {7}, pages = {2939-2955}, doi = {10.1111/1462-2920.15051}, pmid = {32372498}, issn = {1462-2920}, support = {704903//H2020 Marie Skłodowska-Curie Actions/International ; 249793 and 240483//Norges Forskningsråd/International ; //Universitetet i Oslo Department of Biosciences - COMPI/International ; }, mesh = {Adhesins, Bacterial ; Animals ; Biofilms ; Fish Diseases/*microbiology ; Type V Secretion Systems/*metabolism ; Virulence/*genetics ; Virulence Factors/genetics ; Yersinia Infections/*microbiology/prevention & control ; Yersinia ruckeri/*genetics/*pathogenicity ; }, abstract = {Yersinia ruckeri causes enteric redmouth disease (ERM) that mainly affects salmonid fishes and leads to significant economic losses in the aquaculture industry. An increasing number of outbreaks and the lack of effective vaccines against some serotypes necessitates novel measures to control ERM. Importantly, Y. ruckeri survives in the environment for long periods, presumably by forming biofilms. How the pathogen forms biofilms and which molecular factors are involved in this process, remains unclear. Yersinia ruckeri produces two surface-exposed adhesins, belonging to the inverse autotransporters (IATs), called Y. ruckeri invasin (YrInv) and Y. ruckeri invasin-like molecule (YrIlm). Here, we investigated whether YrInv and YrIlm play a role in biofilm formation and virulence. Functional assays revealed that YrInv and YrIlm promote biofilm formation on different abiotic substrates. Confocal microscopy revealed that they are involved in microcolony interaction and formation, respectively. The effect of both IATs on biofilm formation correlated with the presence of different biopolymers in the biofilm matrix, including extracellular DNA, RNA and proteins. Moreover, YrInv and YrIlm contributed to virulence in the Galleria mellonella infection model. Taken together, we propose that both IATs are possible targets for the development of novel diagnostic and preventative strategies to control ERM.}, } @article {pmid32372396, year = {2020}, author = {Köder, K and Hardt, S and Gellert, MS and Haupenthal, J and Renz, N and Putzier, M and Perka, C and Trampuz, A}, title = {Outcome of spinal implant-associated infections treated with or without biofilm-active antibiotics: results from a 10-year cohort study.}, journal = {Infection}, volume = {48}, number = {4}, pages = {559-568}, pmid = {32372396}, issn = {1439-0973}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Child ; Cohort Studies ; Female ; Germany ; Humans ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Postoperative Complications/drug therapy/*microbiology ; Proportional Hazards Models ; Prostheses and Implants/*statistics & numerical data ; Prosthesis-Related Infections/*drug therapy/microbiology ; Spine/surgery ; *Treatment Failure ; Young Adult ; }, abstract = {PURPOSE: Biofilm-active antibiotics are suggested to improve the outcome of implant-associated infections; however, their role in infections after spinal instrumentation is unclear. Therefore, we evaluated the outcome of patients with spinal implant-associated infections treated with and without biofilm-active antibiotics.

METHODS: The probability of infection-free survival was estimated for treatment of spinal implant-associated infections with and without biofilm-active antibiotics using the Kaplan-Meier method; Cox proportional-hazards regression model was used to identify factors associated with treatment failure.

RESULTS: Among 93 included patients, early-onset infection was diagnosed in 61 (66%) and late-onset in 32 infections (34%). Thirty patients (32%) were treated with biofilm-active antibiotic therapy and 63 (68%) without it. The infection-free survival after a median follow-up of 53.7 months (range, 8 days-9.4 years) was 67% (95% confidence interval [CI], 55-82%) after 1 year and 58% (95% CI 43-71%) after 2 years. The infection-free survival after 1 and 2 years was 94% (95% CI 85-99%) and 84% (95% CI 71-93%) for patients treated with biofilm-active antibiotics, respectively, and 57% (95% CI 39-80%) and 49% (95% CI 28-61%) for those treated without biofilm-active antibiotics, respectively (p = 0.009). Treatment with biofilm-active antibiotics (hazard ratio [HR], 0.23, 95% CI 0.07-0.77), infection with Staphylococcus auras (HR, 2.19, 95% CI 1.04-4.62) and polymicrobial infection (HR, 2.44, 95% CI 1.09-6.04) were significantly associated with treatment outcome. Severe pain was observed more often in patients without biofilm-active antibiotic therapy (49% vs. 18%, p = 0.027).

CONCLUSION: Treatment with biofilm-active antibiotics was associated with better treatment outcome and less postoperative pain intensity.}, } @article {pmid32371860, year = {2020}, author = {Gu, H and Lee, SW and Carnicelli, J and Zhang, T and Ren, D}, title = {Magnetically driven active topography for long-term biofilm control.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {2211}, pmid = {32371860}, issn = {2041-1723}, support = {R21 AI142424/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/microbiology/prevention & control ; Biofilms/drug effects/*growth & development ; Biomass ; Electromagnetic Fields ; Microbial Sensitivity Tests/methods ; Prosthesis-Related Infections/microbiology/prevention & control ; Pseudomonas aeruginosa/drug effects/metabolism/*physiology ; Staphylococcus aureus/drug effects/metabolism/*physiology ; Time Factors ; Uropathogenic Escherichia coli/drug effects/metabolism/*physiology ; }, abstract = {Microbial biofilm formation on indwelling medical devices causes persistent infections that cannot be cured with conventional antibiotics. To address this unmet challenge, we engineer tunable active surface topographies with micron-sized pillars that can beat at a programmable frequency and force level in an electromagnetic field. Compared to the flat and static controls, active topographies with the optimized design prevent biofilm formation and remove established biofilms of uropathogenic Escherichia coli (UPEC), Pseudomonas aeruginosa, and Staphylococcus aureus, with up to 3.7 logs of biomass reduction. In addition, the detached biofilm cells are found sensitized to bactericidal antibiotics to the level comparable to exponential-phase planktonic cells. Based on these findings, a prototype catheter is engineered and found to remain clean for at least 30 days under the flow of artificial urine medium, while the control catheters are blocked by UPEC biofilms within 5 days.}, } @article {pmid32371322, year = {2020}, author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Esposito, G}, title = {Simultaneous nitrification, denitrification and phosphorus removal in a continuous-flow moving bed biofilm reactor alternating microaerobic and aerobic conditions.}, journal = {Bioresource technology}, volume = {310}, number = {}, pages = {123453}, doi = {10.1016/j.biortech.2020.123453}, pmid = {32371322}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Nitrification ; Nitrogen ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; }, abstract = {A continuous-flow moving bed biofilm reactor (IAMBBR) alternating microaerobic and aerobic conditions was used to remove carbon, nitrogen and phosphorus through simultaneous nitrification and denitrification coupled to phosphorus removal (SNDPR). The IAMBBR was operated under different dissolved oxygen (DO) ranges (0.2-2, 0.2-3 and 0.2-4 mg L[-1]) and feed C/N ratios (2.8, 3.6 and 4.2) at HRT of 1 day. At a DO range of 0.2-3 mg L[-1] and feed C/N ratio of 3.6, the IAMBBR achieved simultaneous removal of dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO4[3-] with average efficiencies of 100%, 62% and 75%, respectively. Illumina sequencing revealed the coexistence of nitrifiers and P-accumulating denitrifiers (e.g. Hydrogenophaga) in the IAMBBR biofilm. Batch activity tests showed that phosphorus uptake did not occur under stable anaerobic or anoxic conditions, nor under aerobic conditions in absence of nitrate.}, } @article {pmid32371288, year = {2020}, author = {He, L and Rong, H and Wu, D and Li, M and Wang, C and Tong, M}, title = {Influence of biofilm on the transport and deposition behaviors of nano- and micro-plastic particles in quartz sand.}, journal = {Water research}, volume = {178}, number = {}, pages = {115808}, doi = {10.1016/j.watres.2020.115808}, pmid = {32371288}, issn = {1879-2448}, mesh = {Biofilms ; Osmolar Concentration ; *Plastics ; Porosity ; *Quartz ; Sand ; Silicon Dioxide ; }, abstract = {Biofilm, community of bacteria ubiquitously present in natural environment, may interact with plastic particles and affect the transport of plastic particles in environment. The significance of biofilm (Escherichia coli) on the transport and deposition behaviors of three different sized plastic particles (0.02 μm NPs, 0.2 μm MP and 2 μm MP) were examined under both 10 mM and 50 mM NaCl solutions by comparing the breakthrough curves and retained profiles of plastic particles in bare sand versus those in biofilm-coated sand. Regardless of ionic strengths, the presence of biofilm increases the deposition of all three sized plastic particles in porous media. Via employing X-ray microtomography imaging (XMT) and Scanning electron microscope (SEM), we find that the presence of biofilm could narrow the flow path especially near to the inlet of the column and increase the surface roughness of porous media (by decreasing DLVO repulsive interaction), which contributes to the enhanced the deposition of plastic particles. Extracellular polymeric substances (EPS) present on the biofilm are found to contribute to the enhanced deposition of plastic particles. Packed column experiments, quartz crystal microbalance with dissipation (QCM-D) as well as parallel plate flow chamber experiments all show that three major components of EPS, proteins, polysaccharide, and humic substances all contribute to the enhanced deposition of plastic particles. O-H and N-H groups present on cell surfaces are highly likely to form hydrogen bond with plastic particles and increase the deposition plastic particles. Elution experiments show that decreasing solution ionic strength could release small portion of plastic particles from both bare and biofilm-coated sand columns especially from the segments near to the column inlet (with slighter lower percentage from biofilm-coated columns based on the total mass of retained plastics). In contrast, increasing flow rate does not obviously detach the plastic particles that already deposited onto porous media. The results of this study clearly show that the presence of biofilm in natural environment could enhance the deposition and decrease the transport of plastic particles.}, } @article {pmid32369936, year = {2020}, author = {Tseng, YK and Chen, YC and Hou, CJ and Deng, FS and Liang, SH and Hoo, SY and Hsu, CC and Ke, CL and Lin, CH}, title = {Evaluation of Biofilm Formation in Candida tropicalis Using a Silicone-Based Platform with Synthetic Urine Medium.}, journal = {Microorganisms}, volume = {8}, number = {5}, pages = {}, pmid = {32369936}, issn = {2076-2607}, support = {NTU-109L7813//National Taiwan University/ ; }, abstract = {Molecular mechanisms of biofilm formation in Candida tropicalis and current methods for biofilm analyses in this fungal pathogen are limited. (2) Methods: Biofilm biomass and crystal violet staining of the wild-type and each gene mutant strain of C. tropicalis were evaluated on silicone under synthetic urine culture conditions. (3) Results: Seven media were tested to compare the effects on biofilm growth with or without silicone. Results showed that biofilm cells of C. tropicalis were unable to form firm biofilms on the bottom of 12-well polystyrene plates. However, on a silicone-based platform, Roswell Park Memorial Institute 1640 (RPMI 1640), yeast nitrogen base (YNB) + 1% glucose, and synthetic urine media were able to induce strong biofilm growth. In particular, replacement of Spider medium with synthetic urine in the adherence step and the developmental stage is necessary to gain remarkably increased biofilms. Interestingly, unlike Candida albicans, the C. tropicalis ROB1 deletion strain but not the other five biofilm-associated mutants did not cause a significant reduction in biofilm formation, suggesting that the biofilm regulatory circuits of the two species are divergent. (4) Conclusions: This system for C. tropicalis biofilm analyses will become a useful tool to unveil the biofilm regulatory network in C. tropicalis.}, } @article {pmid32367731, year = {2020}, author = {Lethongkam, S and Daengngam, C and Tansakul, C and Siri, R and Chumpraman, A and Phengmak, M and Voravuthikunchai, SP}, title = {Prolonged inhibitory effects against planktonic growth, adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube.}, journal = {Biofouling}, volume = {36}, number = {3}, pages = {292-307}, doi = {10.1080/08927014.2020.1759041}, pmid = {32367731}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects ; Disposable Equipment/*microbiology ; Equipment Contamination/prevention & control ; Humans ; Intubation, Intratracheal ; Metal Nanoparticles/*chemistry ; Nylons/chemistry/*pharmacology ; Plankton/*drug effects/growth & development/microbiology ; Pneumonia, Ventilator-Associated/*microbiology/prevention & control ; Pseudomonas aeruginosa/drug effects ; Silver/chemistry/*pharmacology ; Staphylococcus aureus/drug effects ; }, abstract = {Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ∼ 17 ± 3 µm accommodating high loading of 60 ± 35 nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p < 0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72 h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.}, } @article {pmid32367541, year = {2020}, author = {Fadhlaoui, M and Laderriere, V and Lavoie, I and Fortin, C}, title = {Influence of Temperature and Nickel on Algal Biofilm Fatty Acid Composition.}, journal = {Environmental toxicology and chemistry}, volume = {39}, number = {8}, pages = {1566-1577}, doi = {10.1002/etc.4741}, pmid = {32367541}, issn = {1552-8618}, support = {//Fonds Québécois de la Recherche sur la Nature et les Technologies/International ; //Canada Research Chair program/International ; //Knowledge CREATE program/International ; }, mesh = {Biofilms/*drug effects ; Chlorophyta/*drug effects ; Fatty Acids/*metabolism ; Fatty Acids, Unsaturated/metabolism ; Nickel/*pharmacology ; Principal Component Analysis ; Stress, Physiological/drug effects ; *Temperature ; }, abstract = {Freshwater biofilms play an important role in aquatic ecosystems and are widely used to evaluate environmental conditions. Little is known about the effects of temperature and metals on biofilm fatty acid composition. In the present study, we exposed a natural biofilm cultured in mesocosms to a gradient of nickel (Ni) concentrations at 15 and 21 °C for 28 d. Metal bioaccumulation, algal taxonomic composition, and biofilm fatty acid profiles were determined. At both temperatures, bioaccumulated Ni increased with Ni exposure concentration and reached the highest values at 25 µM Ni, followed by a decrease at 55 and 105 µM Ni. In control biofilms, palmitic acid (16:0), palmitoleic acid (16:1n7), oleic acid (18:1n9), linoleic acid (18:2n6), and linolenic acid (18:3n3) were the dominant fatty acids at 15 and 21 °C. This composition suggests a dominance of cyanobacteria and green algae, which was subsequently confirmed by microscopic observations. The increase in temperature resulted in a decrease in the ratio of unsaturated to saturated fatty acids, which is considered to be an adaptive response to temperature variation. Polyunsaturated fatty acids (PUFAs) tended to decrease along the Ni gradient, as opposed to saturated fatty acids which increased with Ni concentrations. Temperature and Ni affected differently the estimated desaturase and elongase activities (product/precursor ratios). The increase in PUFAs at 15 °C was concomitant to an increase in Δ9-desaturase (D9D). The estimated activities of D9D, Δ12-desaturase, and Δ15-desaturase decreased along the Ni gradient and reflected a decline in PUFAs. The elevated estimated elongase activity reflected the observed increase in saturated fatty acids at the highest Ni exposure concentration (105 µM). Our results suggest that fatty acids could be used as an endpoint to evaluate environmental perturbations. Environ Toxicol Chem 2020;39:1566-1577. © 2020 SETAC.}, } @article {pmid32367495, year = {2020}, author = {Punniyakotti, P and Panneerselvam, P and Perumal, D and Aruliah, R and Angaiah, S}, title = {Anti-bacterial and anti-biofilm properties of green synthesized copper nanoparticles from Cardiospermum halicacabum leaf extract.}, journal = {Bioprocess and biosystems engineering}, volume = {43}, number = {9}, pages = {1649-1657}, doi = {10.1007/s00449-020-02357-x}, pmid = {32367495}, issn = {1615-7605}, support = {PDF/2017/001134//Science and Engineering Research Board/ ; }, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry ; Biofilms/*drug effects/growth & development ; *Copper/chemistry/pharmacology ; Green Chemistry Technology ; *Metal Nanoparticles/chemistry/therapeutic use ; Plant Extracts/*chemistry ; Plant Leaves/*chemistry ; Sapindaceae/*chemistry ; }, abstract = {In the present study, a copper nanoparticle (Cu NPs) was synthesized by a green synthesis method with Cardiospermum halicacabum leaf extract. The surface area of Cu NPs was measured with dynamic light scattering (DLS). UV-Vis spectrum clearly illustrates the typical absorption peak of Cu NPs. The crystalline property of Cu NPs was confirmed from the XRD pattern. TEM analysis clearly indicates the average particle size of synthesized Cu NPs was in the range of 30-40 nm with hexagonal shape. Energy-dispersive spectroscopy confirms the major strong peaks of Cu NPs. FTIR analysis confirms the existence of various functional biomolecules over the metal nanoparticles and they are playing an important role in the formation of Cu NPs. The antibacterial and anti-biofilm analyses were carried out to confirm their aptitude for biomedical applications. Interestingly, Cu NPs control the development of biofilm by attaching over the cell wall and disturb their growth and development.}, } @article {pmid32366710, year = {2020}, author = {Bilal, H and Bergen, PJ and Tait, JR and Wallis, SC and Peleg, AY and Roberts, JA and Oliver, A and Nation, RL and Landersdorfer, CB}, title = {Clinically Relevant Epithelial Lining Fluid Concentrations of Meropenem with Ciprofloxacin Provide Synergistic Killing and Resistance Suppression of Hypermutable Pseudomonas aeruginosa in a Dynamic Biofilm Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {7}, pages = {}, pmid = {32366710}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Ciprofloxacin/pharmacology ; Humans ; Meropenem/pharmacology ; Microbial Sensitivity Tests ; *Pseudomonas Infections/drug therapy ; *Pseudomonas aeruginosa ; }, abstract = {Treatment of exacerbations of chronic Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) is highly challenging due to hypermutability, biofilm formation, and an increased risk of resistance emergence. We evaluated the impact of ciprofloxacin and meropenem as monotherapy and in combination in the dynamic in vitro CDC biofilm reactor (CBR). Two hypermutable P. aeruginosa strains, PAOΔmutS (MIC of ciprofloxacin [MICciprofloxacin], 0.25 mg/liter; MICmeropenem, 2 mg/liter) and CW44 (MICciprofloxacin, 0.5 mg/liter; MICmeropenem, 4 mg/liter), were investigated for 120 h. Concentration-time profiles achievable in epithelial lining fluid (ELF) following FDA-approved doses were simulated in the CBR. Treatments were ciprofloxacin at 0.4 g every 8 h as 1-h infusions (80% ELF penetration), meropenem at 6 g/day as a continuous infusion (CI) (30% and 60% ELF penetration), and their combinations. Counts of total and less-susceptible planktonic and biofilm bacteria and MICs were determined. Antibiotic concentrations were quantified by an ultrahigh-performance liquid chromatography photodiode array (UHPLC-PDA) assay. For both strains, all monotherapies failed, with substantial regrowth and resistance of planktonic (≥8 log10 CFU/ml) and biofilm (>8 log10 CFU/cm[2]) bacteria at 120 h (MICciprofloxacin, up to 8 mg/liter; MICmeropenem, up to 64 mg/liter). Both combination treatments demonstrated synergistic bacterial killing of planktonic and biofilm bacteria of both strains from ∼48 h onwards and suppressed regrowth to ≤4 log10 CFU/ml and ≤6 log10 CFU/cm[2] at 120 h. Overall, both combination treatments suppressed the amplification of resistance of planktonic bacteria for both strains and of biofilm bacteria for CW44. The combination with meropenem at 60% ELF penetration also suppressed the amplification of resistance of biofilm bacteria for PAOΔmutS Thus, combination treatment demonstrated synergistic bacterial killing and resistance suppression against difficult-to-treat hypermutable P. aeruginosa strains.}, } @article {pmid32366054, year = {2020}, author = {Kabel, KI and Labena, A and Keshawy, M and Hozzein, WN}, title = {Progressive Applications of Hyperbranched Polymer Based on Diarylamine: Antimicrobial, Anti-Biofilm and Anti-Aerobic Corrosion.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {9}, pages = {}, pmid = {32366054}, issn = {1996-1944}, support = {RSP-2019/53//King Saud University/ ; }, abstract = {New generations of hyperbranched aramids were synthesized from diarylamine and methyl acrylate using an AB2 monomer approach in a straightforward one-pot preparation. The chemical structure of hyperbranched Phenylenediamine/Methyl Acrylate HB(PDMA was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance ([1]HNMR) spectroscopy. In addition, the particle's size and distribution were recorded using Dynamic Light Scattering (DLS). Moreover, the synthesized HB(PDMA)s displayed broad-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria as well as yeast strains and anti-biofilm activity where the highest activity was attributed to HB(PDMA)G4 at the lowest Minimum Inhibitory, Minimum Bactericidal, and Fungicidal Concentrations (MIC, MBC, and MFC, respectively). Furthermore, the HB(PDMA)s expressed anti-bacterial activity against isolated Pseudomonas sp. (R301) at a salinity of 35,000 ppm (NaCl). In addition, they revealed different corrosion inhibition efficiencies at the cultivated medium salinity at the estimated minimum bactericidal concentrations. The highest metal corrosion inhibition efficiencies were 59.5 and 94.3% for HB(PDMA)G4 at the Minimum Bactericidal Concentrations (MBCs) and two times Minimum Bactericidal Concentrations (2XMBCs), respectively, in comparison to both negative and positive controls.}, } @article {pmid32365789, year = {2020}, author = {Whelan, S and O'Grady, MC and Corcoran, D and Finn, K and Lucey, B}, title = {Uropathogenic Escherichia coli Biofilm-Forming Capabilities are not Predictable from Clinical Details or from Colonial Morphology.}, journal = {Diseases (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {32365789}, issn = {2079-9721}, support = {RISAM_SW_2018//Cork Institute of Technology/ ; }, abstract = {Antibiotic resistance is increasing to an extent where efficacy is not guaranteed when treating infection. Biofilm formation has been shown to complicate treatment, whereby the formation of biofilm is associated with higher minimum inhibitory concentration values of antibiotic. The objective of the current paper was to determine whether biofilm formation is variable among uropathogenic Escherichia coli isolates and whether formation is associated with recurrent urinary tract infection (UTI), and whether it can be predicted by phenotypic appearance on culture medium A total of 62 E. coli isolates that were reported as the causative agent of UTI were studied (33 from patients denoted as having recurrent UTI and 29 from patients not specified as having recurrent UTI). The biofilm forming capability was determined using a standard microtitre plate method, using E. coli ATCC 25922 as the positive control. The majority of isolates (93.6%) were found to be biofilm formers, whereby 81% were denoted as strong or very strong producers of biofilm when compared to the positive control. Through the use of a Wilcox test, the difference in biofilm forming propensity between the two patient populations was found to not be statistically significant (p = 0.5). Furthermore, it was noted that colony morphology was not a reliable predictor of biofilm-forming propensity. The findings of this study indicate that biofilm formation is very common among uropathogens, and they suggest that the biofilm-forming capability might be considered when treating UTI. Clinical details indicating a recurrent infection were not predictors of biofilm formation.}, } @article {pmid32365462, year = {2020}, author = {Alves, P and Gomes, LC and Rodríguez-Emmenegger, C and Mergulhão, FJ}, title = {Efficacy of A Poly(MeOEGMA) Brush on the Prevention of Escherichia coli Biofilm Formation and Susceptibility.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {5}, pages = {}, pmid = {32365462}, issn = {2079-6382}, support = {346972946//Deutsche Forschungsgemeinschaft/ ; UIDB/00511/2020//Fundação para a Ciência e a Tecnologia/ ; PD/BD/114317/2016//Fundação para a Ciência e a Tecnologia/ ; CEECIND/01700/2017//Fundação para a Ciência e a Tecnologia/ ; 19893 N//Forschungskuratorium Textil, Bundesministerium für Wirtschaft und Energie/ ; }, abstract = {Urinary tract infections are one of the most common hospital-acquired infections, and they are often associated with biofilm formation in indwelling medical devices such as catheters and stents. This study aims to investigate the antibiofilm performance of a polymer brush-poly[oligo(ethylene glycol) methyl ether methacrylate], poly(MeOEGMA)-and evaluate its effect on the antimicrobial susceptibility of Escherichia coli biofilms formed on that surface. Biofilms were formed in a parallel plate flow chamber (PPFC) for 24 h under the hydrodynamic conditions prevailing in urinary catheters and stents and challenged with ampicillin. Results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) and glass. The polymer brush reduced by 57% the surface area covered by E. coli after 24 h, as well as the number of total adhered cells. The antibiotic treatment potentiated cell death and removal, and the total cell number was reduced by 88%. Biofilms adapted their architecture, and cell morphology changed to a more elongated form during that period. This work suggests that the poly(MeOEGMA) brush has potential to prevent bacterial adhesion in urinary tract devices like ureteral stents and catheters, as well as in eradicating biofilms developed in these biomedical devices.}, } @article {pmid32365130, year = {2020}, author = {De Natale, A and Mele, BH and Cennamo, P and Del Mondo, A and Petraretti, M and Pollio, A}, title = {Microbial biofilm community structure and composition on the lithic substrates of Herculaneum Suburban Baths.}, journal = {PloS one}, volume = {15}, number = {5}, pages = {e0232512}, pmid = {32365130}, issn = {1932-6203}, mesh = {Baths/*history ; Biofilms/*growth & development ; Construction Materials/history/microbiology ; Environmental Microbiology ; History, Ancient ; Humans ; Italy ; *Microbiota/genetics ; Microscopy, Confocal ; }, abstract = {In this work, we want to investigate the impact of different substrates and different environmental condition on the biofilm communities growing on plaster, marble, and mortar substrates inside the Herculaneum Suburban Baths. To do so, we measured environmental conditions and sampled biofilm communities along the walls of the baths and used culture-dependent and -independent molecular techniques (DGGE) to identify the species at each sampling sites. We used the species pool to infer structure and richness of communities within each site in each substrate, and confocal light scanning microscopy to assess the three-dimensional structure of the sampled biofilms. To gather further insights, we built a meta-community network and used its local realizations to analyze co-occurrence patterns of species. We found that light is a limiting factor in the baths environment, that moving along sites equals moving along an irradiation gradient, and that such gradient shapes the community structure, de facto separating a dark community, rich in Bacteria, Fungi and cyanobacteria, from two dim communities, rich in Chlorophyta. Almost all sites are dominated by photoautotrophs, with Fungi and Bacteria relegated to the role of rare species., and structural properties of biofilms are not consistent within the same substrate. We conclude that the Herculaneum suburban baths are an environment-shaped community, where one dark community (plaster) and one dim community (mortar) provides species to a "midway" community (marble).}, } @article {pmid32363762, year = {2020}, author = {Vera-González, N and Bailey-Hytholt, CM and Langlois, L and de Camargo Ribeiro, F and de Souza Santos, EL and Junqueira, JC and Shukla, A}, title = {Anidulafungin liposome nanoparticles exhibit antifungal activity against planktonic and biofilm Candida albicans.}, journal = {Journal of biomedical materials research. Part A}, volume = {108}, number = {11}, pages = {2263-2276}, doi = {10.1002/jbm.a.36984}, pmid = {32363762}, issn = {1552-4965}, mesh = {Anidulafungin/administration & dosage/*pharmacology ; Animals ; Antifungal Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Candidiasis/drug therapy/veterinary ; Humans ; Liposomes/chemistry ; Nanoparticles/chemistry ; Plankton/drug effects ; }, abstract = {Fungal infections can cause significant patient morbidity and mortality. Nanoparticle therapeutics have the potential to improve treatment of these infections. Here we report the development of liposomal nanoparticles incorporating anidulafungin, a potent antifungal, with the goal of increasing its solubility and aiding in localization to fungi. Liposomes were fabricated with three concentrations of anidulafungin yielding monodisperse ~100 nm unilamellar vesicles. All three formulations inhibited planktonic Candida albicans growth at a minimum inhibitory concentration equivalent to free drug. All three formulations also disrupted preformed C. albicans biofilms, reducing fungal burden by as much as 99%, exhibiting superior biofilm disruption compared with free drug. Liposome formulations tested in vivo in C. albicans infected Galleria mellonella wax moth larvae demonstrated increased survival compared to free drug equivalents, leading to a survival of 33 to 67% of larvae over 7 days depending on the liposome utilized compared with only 25% survival of larvae administered free drug. Liposomal formulations along with free anidulafungin did not cause red blood cell lysis. Ultimately, the liposome formulations reported here increased anidulafungin solubility, displayed promising efficacy against planktonic and biofilm C. albicans, and improved the survival of C. albicans-infected G. mellonella compared to free anidulafungin.}, } @article {pmid32362877, year = {2020}, author = {Žiemytė, M and Rodríguez-Díaz, JC and Ventero, MP and Mira, A and Ferrer, MD}, title = {Effect of Dalbavancin on Staphylococcal Biofilms When Administered Alone or in Combination With Biofilm-Detaching Compounds.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {553}, pmid = {32362877}, issn = {1664-302X}, abstract = {Microorganisms grown in biofilms are more resistant to antimicrobial treatment and immune system attacks compared to their planktonic forms. In fact, infections caused by biofilm-forming Staphylococcus aureus and Staphylococcus epidermidis are a large threat for public health, including patients with medical devices. The aim of the current manuscript was to test the effect of dalbavancin, a recently developed lipoglycopeptide antibiotic, alone or in combination with compounds contributing to bacterial cell disaggregation, on staphylococcal biofilm formation and elimination. We used real-time impedance measurements in microtiter plates to study biofilm growth dynamics of S. aureus and S. epidermidis strains, in the absence or presence of dalbavancin, linezolid, vancomycin, cloxacillin, and rifampicin. Further experiments were undertaken to check whether biofilm-detaching compounds such as N-acetylcysteine (NAC) and ficin could enhance dalbavancin efficiency. Real-time dose-response experiments showed that dalbavancin is a highly effective antimicrobial, preventing staphylococcal biofilm formation at low concentrations. Minimum biofilm inhibitory concentrations were up to 22 higher compared to standard E-test values. Dalbavancin was the only antimicrobial that could halt new biofilm formation on established biofilms compared to the other four antibiotics. The addition of NAC decreased dalbavancin efficacy while the combination of dalbavancin with ficin was more efficient than antibiotic alone in preventing growth once the biofilm was established. Results were confirmed by classical biofilm quantification methods such as crystal violet (CV) staining and viable colony counting. Thus, our data support the use of dalbavancin as a promising antimicrobial to treat biofilm-related infections. Our data also highlight that synergistic and antagonistic effects between antibiotics and biofilm-detaching compounds should be carefully tested in order to achieve an efficient treatment that could prevent both biofilm formation and disruption.}, } @article {pmid32361449, year = {2020}, author = {Qi, X and Liu, P and Liang, P and Hao, W and Li, M and Li, Q and Zhou, Y and Huang, X}, title = {Biofilm's morphology design for high sensitivity of bioelectrochemical sensor: An experimental and modeling study.}, journal = {The Science of the total environment}, volume = {729}, number = {}, pages = {138908}, doi = {10.1016/j.scitotenv.2020.138908}, pmid = {32361449}, issn = {1879-1026}, mesh = {*Biofilms ; Biomass ; *Electricity ; Electrodes ; }, abstract = {High sensitivity is essential for the application of bioelectrochemical system-based sensor (BES sensor) in water quality early-warning, where the electroactive biofilm is of vital importance as it delivers a responsive electric signal to toxic substances. This study artificially designed the morphology of a naturally formed biofilm by employing a serrated knife to scrape the biofilm and thus obtained a reduced thickness and roughness. Then it was further cut by half to halve the biomass. BES sensors equipped with control and processed biofilms were operated under constant anode potential (CAP) and tested at different Cu(II) concentrations to study their sensitivities. Results revealed that the scraped biofilms delivered much increased sensitivity towards Cu(II) shock, which was attributed to a reduced thickness as illustrated by macroscopic and microscopic morphology analysis. Another finding was that biomass per unit interfacial area, rather than the biomass, also affected the sensitivity. To further describe how the inner biofilm responded the toxicity after morphology design, a one-dimension mass transfer model was developed to simulate the mass transfer of Cu(II) in the biofilms with different thicknesses. The relative threshold value of inlet Cu(II) concentration was employed to fit the modeling and experimental results, indicating that decreased biofilm thickness was beneficial for improving the sensitivity.}, } @article {pmid32360467, year = {2020}, author = {Valliammai, A and Sethupathy, S and Ananthi, S and Priya, A and Selvaraj, A and Nivetha, V and Aravindraja, C and Mahalingam, S and Pandian, SK}, title = {Proteomic profiling unveils citral modulating expression of IsaA, CodY and SaeS to inhibit biofilm and virulence in methicillin-resistant Staphylococcus aureus.}, journal = {International journal of biological macromolecules}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.ijbiomac.2020.04.231}, pmid = {32360467}, issn = {1879-0003}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the dangerous human pathogens and it is categorized as a high priority multi-drug resistant bacterium by WHO. Biofilm forming ability of MRSA is responsible for persistent infections and also difficult to eradicate using antibiotic therapy as biofilm is much more resistant to antibiotics. Thus, targeting biofilm and virulence has become an alternative approach to attenuate the pathogenicity of bacterium without affecting the growth. Hence, the present study was aimed at evaluation of antibiofilm potential of citral against MRSA and to decode the possible mode of action. Citral inhibited biofilm formation by MRSA without affecting growth at 100 μg/mL. Microscopic analyses evidenced that citral greatly hampered the surface adherence of MRSA. Effect of citral on cellular proteome of MRSA was studied using two-dimensional gel electrophoresis (2DGE) and differentially regulated proteins were identified using nano LC-MS/MS and MALDI-TOF/TOF analysis. Gene ontology and STRING analysis revealed that citral differentially regulated the proteins involved in pleotropic transcriptional repression (CodY), cell wall homeostasis (IsaA), regulation of exotoxin secretion (SaeS), cell adhesion, hemolysis, capsular polysaccharide biosynthesis and pathogenesis. Gene expression analysis and in vitro assays further validated the alteration in synthesis of slime, hemolysin, lipase, staphyloxanthin and oxidant susceptibility. Thus, the present study unveiled the multiple protein targeted antibiofilm potential of citral and portrays citral as a promising therapeutic agent to combat biofilm mediated MRSA infections with less possibility of resistance development.}, } @article {pmid32360272, year = {2020}, author = {Vitorino, I and Albuquerque, L and Wiegand, S and Kallscheuer, N and da Costa, MS and Lobo-da-Cunha, A and Jogler, C and Lage, OM}, title = {Alienimonas chondri sp. nov., a novel planctomycete isolated from the biofilm of the red alga Chondrus crispus.}, journal = {Systematic and applied microbiology}, volume = {43}, number = {3}, pages = {126083}, doi = {10.1016/j.syapm.2020.126083}, pmid = {32360272}, issn = {1618-0984}, mesh = {*Biofilms/growth & development ; Fatty Acids/analysis/chemistry ; Genome, Bacterial ; Genomics/methods ; Phylogeny ; Planctomycetales/*classification/*genetics/isolation & purification/ultrastructure ; RNA, Ribosomal, 16S/genetics ; *Rhodophyta/growth & development ; Seaweed/*classification/*genetics/isolation & purification/ultrastructure ; }, abstract = {The phylum Planctomycetes comprises bacteria with peculiar and very unique characteristics among prokaryotes. In marine environments, macroalgae biofilms are well known for harboring planctomycetal diversity. Here, we describe a novel isolate obtained from the biofilm of the red alga Chondrus crispus collected at a rocky beach in Porto, Portugal. The novel strain LzC2[T] is motile, rosette-forming with spherical- to ovoid-shaped cells. LzC2[T] forms magenta- to pinkish-colored colonies in M13 and M14 media. Transmission and scanning electron microscopy observations showed a division by polar and lateral budding. Mother cells are connected to the daughter cells by a tubular neck-like structure. The strain requires salt for growth. Vitamins are not required for growth. Optimal growth occurs from 15 to 30°C and within a pH range from 5.5 to 10.0. Major fatty acids are anteiso-C15:0 (54.2%) and iso-C15:0 (19.5%). Phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid represent the main lipids and menaquinone 6 (MK-6) is the only quinone present. 16S rRNA gene-based phylogenetic analysis supports the affiliation to the phylum Planctomycetes and family Planctomycetaceae, with Alienimonas as the closest relative. Strain LzC2[T] shares 97% 16S rRNA gene sequence similarity with Alienimonas californiensis. LzC2[T] has a genome size of 5.3 Mb and a G+C content of 68.3%. Genotypic and phenotypic comparison with the closest relatives strongly suggest that LzC2[T] (=CECT 30038[T]=LMG XXXT) is a new species of the genus Alienimonas, for which we propose the name Alienimonas chondri sp. nov., represented by LzC2[T] as type strain. 16S rRNA gene accession number: GenBank=MN757873.1. Genome accession number: GenBank=WTPX00000000.}, } @article {pmid32358981, year = {2020}, author = {El-Chami, MF and Mayotte, J and Bonner, M and Holbrook, R and Stromberg, K and Sohail, MR}, title = {Response to the letter to the editor: Wettability and roughness: Important determinants of bacterial adhesion and biofilm formation.}, journal = {Journal of cardiovascular electrophysiology}, volume = {31}, number = {7}, pages = {1886-1887}, doi = {10.1111/jce.14517}, pmid = {32358981}, issn = {1540-8167}, mesh = {*Bacterial Adhesion ; *Biofilms ; Humans ; Materials Testing ; Wettability ; }, } @article {pmid32358834, year = {2020}, author = {Campbell, M and Fathi, R and Cheng, SY and Ho, A and Gilbert, ES}, title = {Rhamnus prinoides (gesho) stem extract prevents co-culture biofilm formation by Streptococcus mutans and Candida albicans.}, journal = {Letters in applied microbiology}, volume = {71}, number = {3}, pages = {294-302}, doi = {10.1111/lam.13307}, pmid = {32358834}, issn = {1472-765X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Candida albicans/drug effects/*growth & development ; Coculture Techniques ; Dental Caries/microbiology/prevention & control ; Plant Extracts/*pharmacology ; Plant Leaves ; Rhamnus/*chemistry ; Streptococcus mutans/drug effects/*growth & development ; }, abstract = {Streptococcus mutans and Candida albicans exhibit a symbiotic relationship to form polymicrobial biofilms that exacerbate oral infections including early-childhood caries, periodontitis and candidiasis. Rhamnus prinoides (gesho) has traditionally been used for the treatment of a variety of illnesses and was recently found to inhibit Gram-positive bacterial biofilm formation. We hypothesized that Rhamnus prinoides extracts have anti-biofilm activity against S. mutans and C. albicans mono- and dual-species biofilms. Ethanol extracts were prepared from gesho stems and leaves; then anti-biofilm activity was assessed using crystal violet, resazurin and XTT staining. Ethanol extracts significantly inhibited Streptococcus mutans and Candida albicans mono-species biofilm formation up to 97 and 75%, respectively. The stem ethanol extract disrupted S. mutans and C. albicans co-culture synergism, with 98% less polymicrobial biofilm formation than the untreated control. Additionally, this extract inhibited planktonic S. mutans cell growth and decreased biofilm polysaccharide production up to 99%. The reduction in polysaccharide production is likely a contributing factor in the anti-biofilm activity of GSE. These findings indicate that gesho or gesho-derived compounds may have potential as additives to oral hygiene products. SIGNIFICANCE AND IMPACT OF THE STUDY: Oral Streptococcus mutans and Candida albicans biofilms are associated with a variety of illnesses. When occurring together, the resulting infections are especially challenging to treat due to enhanced biofilm formation and antibiotic resistance. More therapeutics that can effectively prevent polymicrobial biofilm formation and disrupt interspecies synergism are needed. Rhamnus prinoides ethanol extracts significantly inhibited dual-species biofilm formation and disrupted interspecies synergism.}, } @article {pmid32357560, year = {2020}, author = {Estevez, MB and Raffaelli, S and Mitchell, SG and Faccio, R and Alborés, S}, title = {Biofilm Eradication Using Biogenic Silver Nanoparticles.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {9}, pages = {}, pmid = {32357560}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Cell Membrane/chemistry/drug effects/ultrastructure ; Escherichia coli/chemistry/*drug effects/physiology/ultrastructure ; Fatty Acids/analysis/chemistry/metabolism ; Hydrogen-Ion Concentration ; Metal Nanoparticles/*chemistry/ultrastructure ; Microscopy, Electron, Scanning Transmission ; Osmolar Concentration ; Particle Size ; Phanerochaete/*chemistry ; Silver/*chemistry ; Spectrum Analysis, Raman ; }, abstract = {Microorganisms offer an alternative green and scalable technology for the synthesis of value added products. Fungi secrete high quantities of bioactive substances, which play dual-functional roles as both reducing and stabilizing agents in the synthesis of colloidal metal nanoparticles such as silver nanoparticles, which display potent antimicrobial properties that can be harnessed for a number of industrial applications. The aim of this work was the production of silver nanoparticles using the extracellular cell free extracts of Phanerochaete chrysosporium, and to evaluate their activity as antimicrobial and antibiofilm agents. The 45-nm diameter silver nanoparticles synthesized using this methodology possessed a high negative surface charge close to -30 mV and showed colloidal stability from pH 3-9 and under conditions of high ionic strength ([NaCl] = 10-500 mM). A combination of environmental SEM, TEM, and confocal Raman microscopy was used to study the nanoparticle-E. coli interactions to gain a first insight into their antimicrobial mechanisms. Raman data demonstrate a significant decrease in the fatty acid content of E. coli cells, which suggests a loss of the cell membrane integrity after exposure to the PchNPs, which is also commensurate with ESEM and TEM images. Additionally, these biogenic PchNPs displayed biofilm disruption activity for the eradication of E. coli and C. albicans biofilms.}, } @article {pmid32357268, year = {2020}, author = {Purkait, S and Bhattacharya, A and Bag, A and Chattopadhyay, RR}, title = {Evaluation of antibiofilm efficacy of essential oil components β-caryophyllene, cinnamaldehyde and eugenol alone and in combination against biofilm formation and preformed biofilms of Listeria monocytogenes and Salmonella typhimurium.}, journal = {Letters in applied microbiology}, volume = {71}, number = {2}, pages = {195-202}, doi = {10.1111/lam.13308}, pmid = {32357268}, issn = {1472-765X}, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Eugenol/pharmacology ; Listeria monocytogenes/*drug effects/growth & development ; Microbial Sensitivity Tests ; Oils, Volatile/pharmacology ; Polycyclic Sesquiterpenes/*pharmacology ; Salmonella typhimurium/*drug effects/growth & development ; }, abstract = {The aim of this study was to examine whether the process of initial colonization and the formation of mature biofilm structure of foodborne bacterial pathogens Listeria monocytogenes and Salmonella typhimurium can be impeded by active essential oil components β-caryophyllene, cinnamaldehyde and eugenol at their individual and combined effects. Among the essential oil components tested, cinnamaldehyde and eugenol at their individual effect showed >50% degradation in biofilm biomass against preformed (matured) biofilms of both the studied bacteria, whereas β-caryophyllene failed to do so. In combination, cinnamaldehyde/eugenol blend showed synergistic antibiofilm efficacy against preformed biofilms of both the studied bacteria L. monocytogenes (FICI: 0·24) and S. typhimurium (FICI: 0·40), whereas other tested combinations showed additive antibiofilm efficacy with FICI ranged from 2·02 to 2·35. Essential oil components alone and in combination also showed much higher inhibition effect on biofilm formation at the initial stage compared to their inhibition effect on preformed biofilms. The results provide evidence that cinnamaldehyde/eugenol combination may help in designing a more potent novel, natural antibiofilm blend at sufficiently low concentrations in the food and pharmaceutical industries. SIGNIFICANCE AND IMPACT OF THE STUDY: In the present work, synergistic antibiofilm efficacy of cinnamaldehyde/eugenol combination against established biofilms of foodborne bacterial pathogens Listeria monocytogenes and Salmonella typhimurium has been reported. These synergistic interactions may help in designing a more potent, safe and effective novel natural antibiofilm agent in food and pharmaceutical industries. Besides, this combination will also be helpful in reducing concentration of individual components, thereby minimizing the undesirable impact on sensory properties of food. To our knowledge, this is the first time, synergistic antibiofilm efficacy of cinnamaldehyde/eugenol blend against established biofilms of foodborne bacterial pathogens has been reported.}, } @article {pmid32356400, year = {2020}, author = {Cay, S and Ozeke, O and Ozcan, F and Topaloglu, S and Aras, D}, title = {Wettability and roughness: Important determinants of bacterial adhesion and biofilm formation.}, journal = {Journal of cardiovascular electrophysiology}, volume = {31}, number = {7}, pages = {1885}, doi = {10.1111/jce.14515}, pmid = {32356400}, issn = {1540-8167}, mesh = {*Bacterial Adhesion ; Biofilms ; Humans ; *Pacemaker, Artificial ; Polymers ; Wettability ; Xylenes ; }, } @article {pmid32355781, year = {2020}, author = {Xiang, B and Lei, Y and Chen, Y and Zhao, G and Zhou, Y and Zhou, Y and Huang, Y and Ye, L}, title = {Mechanistic study on the inhibition of Staphylococcus epidermidis biofilm by agrC-specific binding polypeptide.}, journal = {Annals of translational medicine}, volume = {8}, number = {6}, pages = {337}, pmid = {32355781}, issn = {2305-5839}, abstract = {BACKGROUND: Considering the wide-spread misuse of antibiotics, the development of new antibacterial drugs may effectively prevent the emergence of antibiotic resistance in bacteria. The understanding of the mechanism underlying the Staphylococcus epidermidis agrC-specific binding polypeptide-mediated inhibition of S. epidermidis biofilm formation may supply ideas for the development of new antibacterial drugs.

METHODS: S. epidermidis cells were cultured with different concentrations (0, 100, 200, 400, 800, and 1,600 µg/mL) of agrC-specific binding polypeptide (N1) and blank (N0). Crystal violet staining was performed to test the formation of biofilms and to determine the best concentration of agrC-specific binding polypeptides, and the bacterial inhibitory concentration was also determined. At different time points (6, 12, 18, 24, and 30 h), XTT assay was used to measure bacterial viability, and the real-time quantitative polymerase chain reaction was performed to measure the expression of atlE, icaA, fbe, and icaR genes. The sulfuric acid-phenol method was used to determine polysaccharide intercellular adhesin (PIA) levels.

RESULTS: The biofilm formation ability of S. epidermidis was the lowest after treatment with 800 µg/mL agrC-specific binding polypeptide. After 6 h of culture, agrC-specific binding polypeptide upregulated the expression of atlE, icaA, fbe, and icaR and increased the bacterial viability. However, the polypeptide downregulated the expression of atlE, icaA, fbe, and icaR and inhibited S. epidermidis growth and PIA formation after 12 h of culture. Although agrC-specific binding polypeptide upregulated the expression of atlE, icaA, fbe, and icaR after 18 h, they inhibited bacterial growth and PIA formation.

CONCLUSIONS: Thus, agrC-specific binding polypeptide could downregulate the expression of atlE, icaA, fbe, and icaR and inhibit PIA formation by S. epidermidis after 12 h, demonstrating its transient inhibitory effects on the biofilm formation ability of S. epidermidis. Its effective concentration was 800 µg/mL.}, } @article {pmid32355001, year = {2020}, author = {Gallego-Hernandez, AL and DePas, WH and Park, JH and Teschler, JK and Hartmann, R and Jeckel, H and Drescher, K and Beyhan, S and Newman, DK and Yildiz, FH}, title = {Upregulation of virulence genes promotes Vibrio cholerae biofilm hyperinfectivity.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {20}, pages = {11010-11017}, pmid = {32355001}, issn = {1091-6490}, support = {R01 HL117328/HL/NHLBI NIH HHS/United States ; S10 OD023528/OD/NIH HHS/United States ; R01 AI114261/AI/NIAID NIH HHS/United States ; R01 AI102584/AI/NIAID NIH HHS/United States ; R01 AI127850/AI/NIAID NIH HHS/United States ; R01 AI055987/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cholera Toxin ; Disease Models, Animal ; Fimbriae, Bacterial ; *Gene Expression Regulation, Bacterial ; Intestines/diagnostic imaging/microbiology/pathology ; Mice ; Phenotype ; *Up-Regulation ; Vibrio cholerae/*genetics/growth & development ; Virulence/genetics ; Virulence Factors/*genetics ; }, abstract = {Vibrio cholerae remains a major global health threat, disproportionately impacting parts of the world without adequate infrastructure and sanitation resources. In aquatic environments, V. cholerae exists both as planktonic cells and as biofilms, which are held together by an extracellular matrix. V. cholerae biofilms have been shown to be hyperinfective, but the mechanism of hyperinfectivity is unclear. Here we show that biofilm-grown cells, irrespective of the surfaces on which they are formed, are able to markedly outcompete planktonic-grown cells in the infant mouse. Using an imaging technique designed to render intestinal tissue optically transparent and preserve the spatial integrity of infected intestines, we reveal and compare three-dimensional V. cholerae colonization patterns of planktonic-grown and biofilm-grown cells. Quantitative image analyses show that V. cholerae colonizes mainly the medial portion of the small intestine and that both the abundance and localization patterns of biofilm-grown cells differ from that of planktonic-grown cells. In vitro biofilm-grown cells activate expression of the virulence cascade, including the toxin coregulated pilus (TCP), and are able to acquire the cholera toxin-carrying CTXФ phage. Overall, virulence factor gene expression is also higher in vivo when infected with biofilm-grown cells, and modulation of their regulation is sufficient to cause the biofilm hyperinfectivity phenotype. Together, these results indicate that the altered biogeography of biofilm-grown cells and their enhanced production of virulence factors in the intestine underpin the biofilm hyperinfectivity phenotype.}, } @article {pmid32354252, year = {2020}, author = {Mohamed, MSM and Mostafa, HM and Mohamed, SH and Abd El-Moez, SI and Kamel, Z}, title = {Combination of Silver Nanoparticles and Vancomycin to Overcome Antibiotic Resistance in Planktonic/Biofilm Cell from Clinical and Animal Source.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {11}, pages = {1410-1420}, doi = {10.1089/mdr.2020.0089}, pmid = {32354252}, issn = {1931-8448}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Drug Resistance, Microbial/*drug effects ; Humans ; Metal Nanoparticles/*administration & dosage ; Microbial Sensitivity Tests/methods ; Plankton/*drug effects ; Silver/*administration & dosage ; Vancomycin/*pharmacology ; }, abstract = {This study aims to evaluate the prevalence of multidrug-resistant (MDR) and biofilm-forming pathogens from animal source compared to clinical ones. In addition, to assess the antibacterial and antibiofilm activity of silver nanoparticles (AgNPs) alone and/or mixed with vancomycin. Out of 62 bacterial isolates from animal respiratory tract infection (RTI), 50.00% were defined as MDR, while among human ones, 44.00% were MDR. The bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae were the predominant isolated bacteria from both animal and human origin with frequency percentage of 50.00, 22.32, and 18.75, respectively. Among Staph. aureus strains, mecA gene was detected in 60.00% and 61.54% of animal and human isolates, respectively, while mecALGA251 (mecC) gene was detected in 13.33% and 15.38% of animal and human isolates, respectively. Biofilm formation ability among animal isolates was 83.87%, while among human ones was 86.00%. AgNPs were effective in inhibiting planktonic cells with minimal inhibitory concentration (MIC) values (0.625-10 μg/mL), as well as eradicating biofilm with minimal biofilm eradication concentration values (1.25-10 μg/mL). Noticeable low MIC of AgNPs was required for the isolates from animal source (0.625-5 μg/mL) compared to clinical ones (0.625-10 μg/mL). Remarkable reduction in AgNP effective concentration was observed after combination with 1/4 MIC of vancomycin with minimum recorded concentration of 0.08 μg/mL. In conclusion, the prevalence of MDR among RT pathogens was recorded with high ability to produce biofilm and virulence factors from both animal and human pathogens. AgNPs showed strong antibacterial and antibiofilm activity alone and mixed with vancomycin, with up to fourfold reduction of AgNP inhibitory dose.}, } @article {pmid32353392, year = {2020}, author = {Lakshmi, SA and Bhaskar, JP and Krishnan, V and Sethupathy, S and Pandipriya, S and Aruni, W and Pandian, SK}, title = {Inhibition of biofilm and biofilm-associated virulence factor production in methicillin-resistant Staphylococcus aureus by docosanol.}, journal = {Journal of biotechnology}, volume = {317}, number = {}, pages = {59-69}, doi = {10.1016/j.jbiotec.2020.04.014}, pmid = {32353392}, issn = {1873-4863}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Erythrocytes ; Fatty Alcohols/*pharmacology ; Hemolysis/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/metabolism ; Sheep ; Transcriptome/drug effects ; Virulence Factors/*metabolism ; }, abstract = {Antimicrobial resistance is a major public health concern in infection control. Hence, a multi-pronged approach is necessary to curb the severity of infections. The present study entails the identification of docosanol (fatty alcohol) from Streptomyces as a novel antibiofilm agent which can target the virulence factors of MRSA. Results showed that docosanol as a potent antibiofilm agent and found to inhibit several virulence factors of MRSA. The antibiofilm efficacy of docosanol analyzed through light and scanning electron microscopy showed a significant reduction in adherent cells. Moreover, analysis of three-dimensional structure of biofilm matrix by confocal laser scanning microscope demonstrated effective antibiofilm potential of docosanol. In addition, docosanol reduced the survival rate of MRSA in healthy human blood and enhanced the neutrophil-mediated killing by interfering with hemolysin production. RT-qPCR analysis revealed the down regulation of several virulence genes, possibly by affecting the expression of the accessory gene regulator (agr) system and transcriptional regulator sarA. These findings suggest that docosanol could effectively reduce the biofilm phenotype and virulence production, and thus becomes a promising candidate to treat MRSA infections.}, } @article {pmid32352767, year = {2020}, author = {Coutaud, M and Paule, A and Méheut, M and Viers, J and Rols, JL and Pokrovsky, OS}, title = {Elemental and Isotopic Variations of Copper and Zinc Associated with the Diel Activity of Phototrophic Biofilm.}, journal = {Environmental science & technology}, volume = {54}, number = {11}, pages = {6741-6750}, doi = {10.1021/acs.est.0c00733}, pmid = {32352767}, issn = {1520-5851}, mesh = {Biofilms ; *Copper ; Isotopes ; Organic Chemicals ; *Zinc ; }, abstract = {The response in metal concentrations and isotopic composition to variations in photosynthetic activity of aquatic micro-organisms is crucially important for understanding the environmental controls on metal fluxes and isotope excursions. Here we studied the impacts of two successive diel cycles on physicochemical parameters, Cu and Zn concentrations, and isotopic composition in solution in the presence of mature phototrophic biofilm in a rotating annular bioreactor. The diel cycles induced fluctuations in temperature, pH, and dissolved oxygen concentration following the variation in the photosynthesis activity of the biofilm. Diel variations in metal concentrations were primarily related to the pH variation, with an increase in metal concentration in solution related to a pH decrease. For both metals, δ([66]Zn) and δ([65]Cu) in solution exhibited complex but reproducible diel cycles. Diel variations in photosynthetic activity led to alternatively positive and negative isotope fractionation, producing the sorption of light Zn (Δ([66]Znsorbed-solution) = -0.1 ± 0.06‰) and heavy Cu isotopes (Δ([65]Cusorbed-solution) = +0.17 ± 0.06‰) during the day at high pH and the excretion of lighter Zn isotopes (-0.4‰ < Δ([66]Znexcreted-biofilm) < +0.14‰) and heavy Cu isotopes (Δ([65]Cuexcreted-biofilm) = +0.7 ± 0.3‰) during the night at lower pH. We interpreted Zn and Cu diel cycles as a combination of a desorption of exopolymeric substance-metal complexes and a small active efflux during the night with adsorption and incorporation via an active uptake during the day. The hysteresis of metal concentration in solution over the diel cycle suggested the more important role of uptake compared to desorption and efflux from the biofilm. The phototrophic biofilm presents a non-negligible highly labile metal pool with important potential for contrasting isotopic fractionation at the diel scale.}, } @article {pmid32352288, year = {2020}, author = {Wu, Y and Luo, X and Qin, B and Li, F and Häggblom, MM and Liu, T}, title = {Enhanced Current Production by Exogenous Electron Mediators via Synergy of Promoting Biofilm Formation and the Electron Shuttling Process.}, journal = {Environmental science & technology}, volume = {54}, number = {12}, pages = {7217-7225}, doi = {10.1021/acs.est.0c00141}, pmid = {32352288}, issn = {1520-5851}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Electron Transport ; Electrons ; *Shewanella/genetics ; }, abstract = {Exogenous electron mediators (EMs) can facilitate extracellular electron transfer (EET) via electron shuttling processes, but it is still unclear whether and how biofilm formation is affected by the presence of EMs. Here, the impacts of EMs on EET and biofilm formation were investigated in bioelectrochemical systems (BESs) with Shewanella oneidensis MR-1, and the results showed that the presence of five different EMs led to high density current production. All the EMs substantially promoted biofilm formation with 15-36 times higher total biofilm DNA with EMs than without EMs, and they also increased the production of extracellular polymeric substances, which was favorable for biofilm formation. The current decreased substantially after removing EMs from the medium or by replacing electrodes without biofilm, suggesting that both biofilm and EMs are required for high density current production. EET-related gene expression was upregulated with EMs, resulting in the high flux of cell electron output. A synergistic mechanism was proposed: EMs in suspension were quickly reduced by the cells and reoxidized rapidly by the electrode, resulting in a microenvironment with sufficient oxidized EMs for biofilm formation, and thus, besides the well-known electron shuttling process, the EM-induced high biofilm formation and high Mtr gene expression could jointly contribute to the EET and subsequently produce a high density current. This study provides a new insight into EM-enhanced current production via regulating the biofilm formation and EET-related gene expression.}, } @article {pmid32351494, year = {2020}, author = {Tkhilaishvili, T and Wang, L and Perka, C and Trampuz, A and Gonzalez Moreno, M}, title = {Using Bacteriophages as a Trojan Horse to the Killing of Dual-Species Biofilm Formed by Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {695}, pmid = {32351494}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are pathogens able to colonize surfaces and form together a mixed biofilm. Dual-species biofilms are significantly more resistant to antimicrobials than a monomicrobial community, leading to treatment failure. Due to their rapid bactericidal activity, the self-amplification ability and the biofilm degrading properties, bacteriophages represent a promising therapeutic option in fighting biofilm-related infections. In this study, we investigated the effect of either the simultaneous or staggered application of commercially available phages and ciprofloxacin versus S. aureus/P. aeruginosa dual-species biofilms in vitro. Biofilms were grown on porous glass beads and analyzed over time. Different techniques such as microcalorimetry, sonication and scanning electron microscopy were combined for the evaluation of anti-biofilm activities. Both bacterial species were susceptible to ciprofloxacin and to phages in their planktonic form of growth. Ciprofloxacin tested alone against biofilms required high concentration ranging from 256 to >512 mg/L to show an inhibitory effect, whereas phages alone showed good and moderate activity against MRSA biofilms and dual-species biofilms, respectively, but low activity against P. aeruginosa biofilms. The combination of ciprofloxacin with phages showed a remarkable improvement in the anti-biofilm activity of both antimicrobials with complete eradication of dual-species biofilms after staggered exposure to Pyophage or Pyophage + Staphylococcal phage for 12 h followed by 1 mg/L of ciprofloxacin, a dose achievable by intravenous or oral antibiotic administration. Our study provides also valuable data regarding not only dosage but also an optimal time of antimicrobial exposure, which is crucial in the implementation of combined therapies.}, } @article {pmid32350966, year = {2021}, author = {Dygico, LK and Gahan, CGM and Grogan, H and Burgess, CM}, title = {Examining the efficacy of mushroom industry biocides on Listeria monocytogenes biofilm.}, journal = {Journal of applied microbiology}, volume = {130}, number = {4}, pages = {1106-1116}, doi = {10.1111/jam.14681}, pmid = {32350966}, issn = {1365-2672}, support = {14F881//Department of Agriculture, Food and the Marine/ ; //Teagasc/ ; }, mesh = {Agaricales/*growth & development ; Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Disinfectants/*pharmacology ; Food Contamination/prevention & control ; Food Microbiology ; Fungicides, Industrial/*pharmacology ; Listeria monocytogenes/*drug effects/physiology ; }, abstract = {AIMS: The aim of this study was to test the efficacy of new and currently used biocides in the mushroom industry for inactivating Listeria monocytogenes biofilm.

METHODS AND RESULTS: A laboratory-scale study was initially carried out to test the efficacy of eleven biocidal products against a cocktail of five L. monocytogenes strains that were grown to 3-day biofilms on stainless steel coupons. Biocidal efficacy was then tested under clean and dirty conditions based on the EN 13697:2015 method. The results for the biocides tested ranged between 1·7-log and 6-log reduction of biofilm, with only the efficacy of the sodium hypochlorite-based biocide being significantly reduced in dirty conditions. A pilot-scale trial was then carried out on a subset of biocides against L. monocytogenes on concrete floors in a mushroom growing room and it was found that biocide efficacy in laboratory-scale did not translate well in pilot-scale.

CONCLUSIONS: Biocides that are used in the mushroom industry and potential alternative biocides were determined to be effective against L. monocytogenes biofilm in both laboratory-scale and pilot-scale experiments.

This study has direct impact for the industry as it provides information on the efficacy of currently used biocides and other biocidal products against L. monocytogenes, an added benefit to their primary use.}, } @article {pmid32350287, year = {2020}, author = {Ramos-Vivas, J and Chapartegui-González, I and Fernández-Martínez, M and González-Rico, C and Fortún, J and Escudero, R and Marco, F and Linares, L and Montejo, M and Aranzamendi, M and Muñoz, P and Valerio, M and Aguado, JM and Resino, E and Ahufinger, IG and Vega, AP and Martínez-Martínez, L and Fariñas, MC and , }, title = {Author Correction: Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {7452}, doi = {10.1038/s41598-020-60496-3}, pmid = {32350287}, issn = {2045-2322}, abstract = {An amendment to this paper has been published and can be accessed via a link at the top of the paper.}, } @article {pmid32350164, year = {2020}, author = {Inaba, T and Obana, N and Habe, H and Nomura, N}, title = {Biofilm Formation by Streptococcus mutans is Enhanced by Indole via the Quorum Sensing Pathway.}, journal = {Microbes and environments}, volume = {35}, number = {2}, pages = {}, pmid = {32350164}, issn = {1347-4405}, mesh = {Biofilms/*drug effects/growth & development ; DNA, Bacterial/metabolism ; Indoles/*pharmacology ; Mutation ; *Quorum Sensing/genetics ; Streptococcus mutans/*drug effects/genetics/growth & development/physiology ; }, abstract = {Interspecies interactions among oral microorganisms in the pathogenic biofilms causing dental caries have not yet been elucidated in detail. We herein demonstrated that indole and its derivatives induced biofilm formation by Streptococcus mutans. Indole is an intercellular signaling molecule that is produced by oral bacteria other than S. mutans. The amounts of biofilm and extracellular DNA were significantly increased by the addition of indole and 4-hydroxyindole (4-HI). An examination with quorum sensing mutants showed that the induction of biofilm formation by indole and 4-HI required a quorum sensing system. These results suggest that this intercellular signaling molecule plays a role in pathogenic biofilm formation.}, } @article {pmid32349419, year = {2020}, author = {Dong, J and Zhang, L and Liu, Y and Xu, N and Zhou, S and Yang, Q and Yang, Y and Ai, X}, title = {Thymol Protects Channel Catfish from Aeromonas hydrophila Infection by Inhibiting Aerolysin Expression and Biofilm Formation.}, journal = {Microorganisms}, volume = {8}, number = {5}, pages = {}, pmid = {32349419}, issn = {2076-2607}, support = {2019YFD0901702, 2019YFD0900104//National Key R&D Program of China/ ; 31702368//the National Nature Science Foundation of China/ ; }, abstract = {Aeromonas hydrophila is an opportunistic pathogen responsible for a number of diseases in freshwater farming. Moreover, the bacterium has been identified as a zoonotic pathogen that threatens human health. Antibiotics are widely used for treatments of infectious diseases in aquaculture. However, the abuse of antibiotics has led to the emergence of antimicrobial resistant strains. Thus, novel strategies are required against resistant A. hydrophila strains. The quorum sensing (QS) system, involved in virulence factor production and biofilm formation, is a promising target in identifying novel drugs against A. hydrophila infections. In this study, we found that thymol, at sub-inhibitory concentrations, could significantly reduce the production of aerolysin and biofilm formation by inhibiting the transcription of genes aerA, ahyI, and ahyR. These results indicate that thymol inhibits the quorum sensing system. The protective effects of thymol against A. hydrophila mediated cell injury were determined by live/dead assay and lactate dehydrogenase (LDH) release assay. Moreover, the in vivo study showed that thymol could significantly decrease the mortality of channel catfish infected with A. hydrophila. Taken together, these findings demonstrate that thymol could be chosen as a phytotherapeutic candidate for inhibiting quorum sensing system-mediated aerolysin production and biofilm formation in A. hydrophila.}, } @article {pmid32348684, year = {2020}, author = {Saleh, D and Sharma, M and Seguin, P and Jabaji, S}, title = {Organic acids and root exudates of Brachypodium distachyon: effects on chemotaxis and biofilm formation of endophytic bacteria.}, journal = {Canadian journal of microbiology}, volume = {66}, number = {10}, pages = {562-575}, doi = {10.1139/cjm-2020-0041}, pmid = {32348684}, issn = {1480-3275}, mesh = {Acids/pharmacology ; Bacteria/drug effects/growth & development ; Biofilms/drug effects/*growth & development ; Brachypodium/*chemistry/*microbiology ; Chemotaxis/drug effects/*physiology ; Endophytes/drug effects/*physiology ; Host Microbial Interactions ; Microbial Consortia/drug effects ; Plant Exudates/pharmacology ; Plant Roots/chemistry/microbiology ; }, abstract = {Root colonization by plant-growth-promoting bacteria could not be useful without the beneficial properties of the bacterium itself. Thus, it is necessary to evaluate the bacterial capacity to form biofilms and establish a successful interaction with the plant roots. We assessed the ability of growth-promoting bacterial strains to form biofilm and display chemotactic behaviour in response to organic acids and (or) root exudates of the model plant Brachypodium distachyon. This assessment was based on the evaluation of single strains of bacteria and a multispecies consortium. The strains coexisted together and formed biofilm under biotic (living root) and abiotic (glass) surfaces. Citric acid stimulated biofilm formation in all individual strains, indicating a strong chemotactic behaviour towards organic acids. Recognizing that the transition from single strains of bacteria to a "multicellular" system would not happen without the presence of adhesion, the alginate and exopolysaccharide (EPS) contents were evaluated. The EPS amounts were comparable in single strains and consortium forms. Alginate production increased 160% in the consortium subjected to drought stress (10% PEG). These findings demonstrated that (i) bacteria-bacteria interaction is the hub of various factors that would not only affect their relation but also could indirectly affect the balanced plant-microbe relation and (ii) root exudates could be very selective in recruiting a highly qualified multispecies consortium.}, } @article {pmid32348624, year = {2020}, author = {Mensi, M and Scotti, E and Sordillo, A and Agosti, R and Calza, S}, title = {Plaque disclosing agent as a guide for professional biofilm removal: A randomized controlled clinical trial.}, journal = {International journal of dental hygiene}, volume = {18}, number = {3}, pages = {285-294}, doi = {10.1111/idh.12442}, pmid = {32348624}, issn = {1601-5037}, mesh = {Biofilms ; Dental Care ; *Dental Plaque ; Dental Plaque Index ; Gingiva ; Humans ; }, abstract = {OBJECTIVES: To evaluate through computer software analysis, the efficacy of the use of a plaque disclosing agent as a visual guide for biofilm removal during professional mechanical plaque removal in terms of post-treatment residual plaque area (RPA).

METHODS: Thirty-two healthy patients were selected and randomized in two groups to receive a session of professional mechanical plaque removal with air-polishing followed by ultrasonic instrumentation with (Guided Biofilm therapy-GBT) or without (Control) the preliminary application of a plaque disclosing agent as visual guide. The residual plaque area (RPA) was evaluated through re-application of the disclosing agent and computer software analysis, considering the overall tooth surface and the gingival and coronal portions separately.

RESULTS: A statistically and clinically significant difference between treatments is observed, with GBT achieving an RPA of 6.1% (4.1-9.1) vs 12.0% (8.2-17.3) of the Control on the Gingival surface and of 3.5% (2.3-5.2) vs 9.0% (6-13.1) on the Coronal, with a proportional reduction going from 49.2% (P-value = .018) on the former surface to more than 60% (P-value = .002) on the latter.

CONCLUSION: The application of a plaque disclosing agent to guide plaque removal seems to lead to better biofilm removal.}, } @article {pmid32347873, year = {2020}, author = {He, X and Wu, X and Qiao, Y and Hu, T and Wang, D and Han, X and Li, CM}, title = {Electrical tension-triggered conversion of anaerobic to aerobic respiration of Shewanella putrefaciens CN32 cells while promoting biofilm growth in microbial fuel cells.}, journal = {Chemical communications (Cambridge, England)}, volume = {56}, number = {45}, pages = {6050-6053}, doi = {10.1039/d0cc01605e}, pmid = {32347873}, issn = {1364-548X}, mesh = {Aerobiosis ; Anaerobiosis ; *Bioelectric Energy Sources ; Biofilms/*growth & development ; Electrodes ; Gene Expression Regulation, Bacterial ; Nanostructures ; Shewanella putrefaciens/genetics/*physiology ; }, abstract = {A global gene expression analysis of Shewanella putrefaciens CN32 cells nearby a nanostructured microbial anode reveals an electrical tension-triggered conversion of anaerobic respiration to aerobic respiration with increased excretion of flavin electron shuttles and cytochrome C proteins, which sheds light on the role of electric tension in cell organisms.}, } @article {pmid32346560, year = {2020}, author = {Razali, MH and Ismail, NA and Amin, KAM}, title = {Physical, mechanical, chemical and biological properties data of gellan gum incorporating titanium dioxide nanoparticles biofilm.}, journal = {Data in brief}, volume = {30}, number = {}, pages = {105478}, pmid = {32346560}, issn = {2352-3409}, abstract = {Gellan gum incorporating titanium dioxide nanoparticles biofilm was synthesized and characterized using UV, FTIR and XRD to study their physical and chemical properties. The mechanical properties were measured using universal mechanical testing. Meanwhile, the biological properties were investigated towards for antibacterial and cell proliferation. This comprehensive data are relevant with the research article entitled "Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies" [1].}, } @article {pmid32344238, year = {2020}, author = {Zhao, Y and Shu, X and Tu, Q and Yang, Y and Liu, C and Fu, D and Li, W and Duan, C}, title = {Pollutant removal from agricultural drainage water using a novel double-layer ditch with biofilm carriers.}, journal = {Bioresource technology}, volume = {310}, number = {}, pages = {123344}, doi = {10.1016/j.biortech.2020.123344}, pmid = {32344238}, issn = {1873-2976}, mesh = {Agriculture ; Biofilms ; *Environmental Pollutants ; Nitrogen ; Phosphorus ; *Water ; }, abstract = {Agricultural drainage ditches can prevent flooding and mitigate agricultural pollution; however, the performance is unsatisfactory in plateau areas like the Dianchi Lake basin. Thus, a novel double-layer ditch system (DDS) with a fibrous packing as biofilm carriers was developed to form the carrier-attached biofilms and enhance the pollutant removal. The results indicated the DDS performed better than a single-layer ditch system, and annual average removal efficiencies of TN, NO3[-]-N, NH4[+]-N, TP, COD and SS were 18.61%, 17.13%, 7.74%, 11.90%, 11.95% and 23.71%, respectively. High amount and carbon, nitrogen and phosphorus contents of biofilms are favourable to pollutant removal by DDS. Although bacterial diversity of biofilms remained relatively stable throughout the year, the relative abundance of dominant assemblages varied greatly. Denitrifying microorganisms affiliated with Bacteroidetes might contribute to effective NO3[-]-N reduction. This study demonstrates DDS performed well and provides a novel method for application of biofilm carriers in drainage ditches.}, } @article {pmid32342070, year = {2020}, author = {Jewell, MP and Saccomano, SC and David, AA and Harris, JK and Zemanick, ET and Cash, KJ}, title = {Nanodiagnostics to monitor biofilm oxygen metabolism for antibiotic susceptibility testing.}, journal = {The Analyst}, volume = {145}, number = {11}, pages = {3996-4003}, doi = {10.1039/d0an00479k}, pmid = {32342070}, issn = {1364-5528}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colistin/pharmacology ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Nanoparticles/chemistry ; Oxygen/*analysis/*metabolism ; Porphyrins/chemistry ; Pseudomonas aeruginosa/*drug effects/*metabolism/physiology ; Pyridinium Compounds/chemistry ; Styrenes/chemistry ; Tobramycin/pharmacology ; }, abstract = {In clinical environments, many serious antibiotic-resistant infections are caused by biofilm-forming species. This presents issues when attempting to determine antimicrobial dosing as traditional antibiotic susceptibility tests (ASTs) are typically designed around planktonic bacteria and thus offer information that is not relevant to the biofilm phenotype present in the patient. Even the popular Calgary biofilm device may provide inaccurate minimum biofilm inhibitory concentrations (MBICs) and can be time- and material-intensive. In this work, we present a method utilizing oxygen-sensitive nanosensor technology to monitor the oxygen consumption dynamics of living biofilms as they are exposed to antibiotics. We incorporated our nanosensors into biofilms grown from P. aeruginosa strains of varying sensitivity to traditional classes of antibiotics. Through measuring nanosensor response under antibiotic administration we determined the concentrations able to cease biofilm metabolism. This method provides information on the MBIC as well as kinetic response information in a manner that requires fewer materials and is more reflective of biofilm behavior than a traditional AST.}, } @article {pmid32341917, year = {2020}, author = {Metcalf, DG and Bowler, PG}, title = {Clinical impact of an anti-biofilm Hydrofiber dressing in hard-to-heal wounds previously managed with traditional antimicrobial products and systemic antibiotics.}, journal = {Burns & trauma}, volume = {8}, number = {}, pages = {tkaa004}, pmid = {32341917}, issn = {2321-3868}, abstract = {BACKGROUND: Hard-to-heal wounds are often compromised by the presence of biofilm. This presents an infection risk, yet traditional antimicrobial wound care products and systemic antibiotics are often used despite the uncertainty of therapeutic success and wound progression. The aim of this study was to investigate the clinical impact of a next-generation anti-biofilm Hydrofiber wound dressing (AQUACEL Ag+ Extra[AQAg+ E]) in hard-to-heal wounds that had previously been treated unsuccessfully with traditional silver-, iodine- or polyhexamethylene biguanide (PHMB)-containing dressings and products and/or systemic antibiotics.

METHODS: Clinical case study evaluations of the anti-biofilm dressing were conducted, where deteriorating or stagnant wounds were selected by clinicians and primary dressings were replaced by the anti-biofilm dressing for up to 4 weeks, or as deemed clinically appropriate, with monitoring via case report forms. The data was stratified for cases where traditional silver-, iodine- or PHMB-containing products, or systemic antibiotics, had been used prior to the introduction of the anti-biofilm dressing.

RESULTS: Sixty-five cases were identified for inclusion, wounds ranging in duration from 1 week to 20 years (median: 12 months). In 47 (72%) cases the wounds were stagnant, while 15 (23%) were deteriorating; 3 wounds were not recorded. After an average of 4.2 weeks of management with the anti-biofilm dressing (range: 1-11 weeks), in 11 (17%) cases the wounds had healed (i.e. complete wound closure), 40 (62%) wounds improved, 9 (14%) wounds remained the same and 5 (8%) wounds deteriorated.

CONCLUSIONS: The introduction of this anti-biofilm dressing into protocols of care that had previously involved wound management with traditional antimicrobial products and/or antibiotics was shown to facilitate improvements in the healing status of most of these hard-to-heal wounds. Dressings containing proven anti-biofilm technology, in combination with antimicrobial silver and exudate management technology, appear to be an effective alternative to traditional antimicrobial products and antibiotics in the cases presented here. The use of antimicrobial wound dressings that contain anti-biofilm technology may have a key role to play in more effective wound management and antibiotic stewardship.}, } @article {pmid32339889, year = {2020}, author = {Elmaadawy, K and Hu, J and Guo, S and Hou, H and Xu, J and Wang, D and Liang, T and Yang, J and Liang, S and Xiao, K and Liu, B}, title = {Enhanced treatment of landfill leachate with cathodic algal biofilm and oxygen-consuming unit in a hybrid microbial fuel cell system.}, journal = {Bioresource technology}, volume = {310}, number = {}, pages = {123420}, doi = {10.1016/j.biortech.2020.123420}, pmid = {32339889}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Oxygen ; *Water Pollutants, Chemical ; }, abstract = {An innovative cathodic algal biofilm microbial fuel cell equipped with a bioactive oxygen consuming unit (AB-OCU-MFC) was proposed for enhancing the leachate treatment containing biorefractory organic matters and high strength of ammonium nitrogen. The proposed AB-OCU-MFC performed better with regard to COD, NH4[+]-N, TN removals and algal biomass yield than standalone algal biofilm-MFC and control reactors. AB-OCU-MFC with OCU of 2 cm thickness removed more than 86% of COD, 89.4% of NH4[+]-N, 76.7% of TN and produced a maximum voltage of 0.39 V and biomass productivity of 1.23 g·L[-1]·d[-1]. The High-throughput sequencing of DNA showed a significant change in microbial community of reactors implemented with OCU, in which the ratio of exoelectrogenic bacteria of anode and denitrifying bacteria on cathode were significantly increased. The results obtained by cathodic algal biofilm MFC with low cost and bioactive barrier of OCU, would provide a new sight for practical application of MFC.}, } @article {pmid32339850, year = {2020}, author = {Chotinantakul, K and Chansiw, N and Okada, S}, title = {Biofilm formation and transfer of a streptomycin resistance gene in enterococci from fermented pork.}, journal = {Journal of global antimicrobial resistance}, volume = {22}, number = {}, pages = {434-440}, doi = {10.1016/j.jgar.2020.04.016}, pmid = {32339850}, issn = {2213-7173}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Drug Resistance, Bacterial ; Enterococcus/genetics ; Humans ; *Pork Meat ; *Red Meat ; Streptomycin/pharmacology ; Swine ; }, abstract = {OBJECTIVES: Multidrug-resistant (MDR) enterococci are found extensively in food samples. This study characterized the phenotypic virulence factors and the ability of horizontal gene transfer of a streptomycin resistance gene among enterococci isolated from fermented pork.

METHODS: Thirty-six MDR enterococci were subjected to screening of gelatinase, biofilm formation at various temperatures (4 °C, 25 °C and 37 °C), clumping ability and conjugation.

RESULTS: All gelatinase-positive and clumping-positive strains were Enterococcus faecalis (41.7% and 38.9%, respectively). None of Enterococcus faecium and Enterococcus hirae demonstrated both phenotypes. Moderate and strong biofilm formations were found mostly at optimal temperatures in all the three species tested. However, moderate and weak biofilm formations could be found in 52.8% at 4 °C. No association was observed between biofilm formation and asa1, efaA, gelE and esp genes. Surprisingly, our data revealed evidence of the streptomycin resistance gene (aadE) being transferred among meat E. faecalis isolates as characterized by the pheromone-clumping response.

CONCLUSIONS: Here we report the co-existence of some virulence factors and MDR enterococci from fermented pork. Our data demonstrated for the first time that the aadE gene could be transferred via conjugation among enterococci isolated from meat, contributing to streptomycin resistance. This study highlights the importance of horizontal gene transfer within the food chain reservoir and that transfer to humans might be possible, causing harm or untreatable diseases.}, } @article {pmid32339263, year = {2020}, author = {Ben-Sahil, A and Mohamed, A and Beyenal, H}, title = {Three-dimensional biofilm image reconstruction for assessing structural parameters.}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {8}, pages = {2460-2468}, doi = {10.1002/bit.27363}, pmid = {32339263}, issn = {1097-0290}, support = {1706889//National Science Foundation (NSF)/International ; }, mesh = {Algorithms ; *Biofilms ; Imaging, Three-Dimensional/*methods ; Microscopy, Confocal/*methods ; }, abstract = {Parameters representing three-dimensional (3D) biofilm structure are quantified from confocal laser-scanning microscope (CLSM) images. These 3D parameters describe the distribution of biomass pixels within the space occupied by a biofilm; however, they lack a direct connection to biofilm activity. As a result, researchers choose a handful of parameters without there being a consensus on a standard set of parameters. We hypothesized that a select 3D parameter set could be used to reconstruct a biofilm image and that the reconstructed and original biofilm images would have similar activities. To test this hypothesis, an algorithm was developed to reconstruct a biofilm image with parameters identical to those of the original CLSM image. We introduced an objective method to assess the reconstruction algorithm by comparing the activities of the original and reconstructed biofilm images. We found that biofilm images with identical structural parameters showed nearly identical activities and substrate concentration profiles. This implies that the set containing all common structural parameters can successfully describe biofilm structure. This finding is significant, as it opens the door to the next step, of finding a smaller standard set of biofilm structural parameters that can be used to compare biofilm structure.}, } @article {pmid32338055, year = {2020}, author = {Delpech, G and Ceci, M and Lissarrague, S and García Allende, L and Baldaccini, B and Sparo, M}, title = {In vitro activity of the antimicrobial peptide AP7121 against the human methicillin-resistant biofilm producers Staphylococcus aureus and Staphylococcus epidermidis.}, journal = {Biofouling}, volume = {36}, number = {3}, pages = {266-275}, doi = {10.1080/08927014.2020.1756266}, pmid = {32338055}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Hip Prosthesis/microbiology ; Humans ; In Vitro Techniques ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Plankton/drug effects/microbiology ; Staphylococcal Infections/prevention & control ; Staphylococcus aureus/drug effects/isolation & purification ; Staphylococcus epidermidis/*drug effects/isolation & purification ; }, abstract = {In vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis biofilm producers from blood cultures of patients with prosthetic hip infections was evaluated. The Minimum Inhibitory Concentration (MIC) for AP7121 was determined and the bactericidal activity of AP7121 (MICx1, MICx4) against planktonic cells was studied at 4, 8 and 24 h. The biofilms formed were incubated with AP7121 (MICx1, MICx4) for 1 and 24 h. The anti-adhesion effect of an AP7121-treated inert surface over the highest MIC isolate was studied with scanning electron microscopy (SEM). The bactericidal activity of AP7121 against all the planktonic staphylococcal cells was observed at 4 h at both peptide concentrations. Dose-dependent anti-biofilm activity was detected. AP7121 (MICx4) showed bactericidal activity at 24 h in all isolates. SEM confirmed prevention of biofilm formation. This research showed the in vitro anti-biofilm activity of AP7121 against MRSA and S. epidermidis and the prevention of biofilm formation by them on an abiotic surface.}, } @article {pmid32335654, year = {2019}, author = {Sharma, M and Sapkota, J and Jha, B and Mishra, B and Bhatt, CP}, title = {Biofilm Formation and Extended-Spectrum Beta-Lactamase Producer among Acinetobacter Species Isolated in a Tertiary Care Hospital: A Descriptive Cross-sectional Study.}, journal = {JNMA; journal of the Nepal Medical Association}, volume = {57}, number = {220}, pages = {424-428}, pmid = {32335654}, issn = {1815-672X}, mesh = {Acinetobacter/isolation & purification/physiology ; Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/isolation & purification/*physiology ; Acinetobacter calcoaceticus/isolation & purification/*physiology ; Bacteremia/microbiology ; Biofilms/*growth & development ; Cross-Sectional Studies ; Drug Resistance, Multiple/physiology ; Humans ; Microbial Sensitivity Tests ; Nepal ; Respiratory Tract Infections/microbiology ; Tertiary Care Centers ; Urinary Tract Infections/microbiology ; beta-Lactam Resistance/*physiology ; beta-Lactamases/metabolism ; }, abstract = {INTRODUCTION: Acinetobacter species are short, stout, gram-negative coccobacilli, generally considered to be a relatively low-grade pathogen. However, its resistance towards multiple classes of antibiotics through an array of resistance mechanisms including its ability to form biofilm has led to its emergence as an important pathogen in hospital settings. This study was done to determine the prevalence of biofilm former and Extended-spectrum Beta-Lactamase producer among Acinetobacter species.

METHODS: A descriptive cross-sectional study was done in the clinical microbiology laboratory, Kathmandu Medical College from January to June 2019. Convenient sampling method was used. Ethical approval was taken from the Institutional Review Committee, Ref no. 2812201805. Preliminary identification followed by characterization of Acinetobacter species was done. Antibiotic susceptibility test was done using the Kirby-Bauer method following Clinical and Laboratory Standards Institute guidelines. Extended-spectrum Beta-Lactamase was detected by combined disc method and Biofilm detection was done using congo red agar method. Statistical Package for Social Sciences 16.0 version statistical software package was used for statistical analysis. Point estimate at 95% Confidence Interval was calculated along with frequencyand proportion for binarydata.

RESULTS: Among 108 Acinetobacter species, 86 (79.7%) Acinetobacter calcoaceticus-A. baumannii complex was seen. Seventy-eight (72%) of the isolates were multidrug-resistant, 34 (31%) of the isolates were Extended-spectrum Beta-Lactamase producer and only 10 (9.3%) of the isolates, were biofilm producers.

CONCLUSIONS: Multidrug-resistant Acinetobacter spp. with the ability to produce Extended-spectrum Beta-Lactamase is prevalent in our hospital settings. Strict compliance with infection control practices is necessary to curb its spread.}, } @article {pmid32335283, year = {2020}, author = {Zheng, M and Shi, J and Xu, C and Han, Y and Zhang, Z and Han, H}, title = {Insights into electroactive biofilms for enhanced phenolic degradation of coal pyrolysis wastewater (CPW) by magnetic activated coke (MAC): Metagenomic analysis in attached biofilm and suspended sludge.}, journal = {Journal of hazardous materials}, volume = {395}, number = {}, pages = {122688}, doi = {10.1016/j.jhazmat.2020.122688}, pmid = {32335283}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors ; Coal ; *Coke ; Magnetic Phenomena ; Phenols ; Pyrolysis ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {To investigate the role of electroactive biofilms for enhanced phenolic degradation, lignite activated coke (LAC) and MAC were used as carriers in moving-bed biofilm reactor (MBBR) for CPW treatment. In contrast to activated sludge (AS) reactor, the carriers improved degradation performance of MBBR. Although two MBBRs exerted similar degradation capacity with over 92% of COD and 93% phenols removal under the highest phenolics concentration (500 mg/L), the effluent of MAC-based MBBR remained higher biodegradability (BOD5/COD = 0.34 vs 0.18) than that of LAC-based MBBR. Metagenomic analysis revealed that electroactive biofilms determined phenolic degradation of MAC-based MBBR. Primarily, Geobacter (17.33%) started Fe redox cycle on biofilms and developed syntrophy with Syntrophorhabdus (6.47%), which fermented phenols into easily biodegradable substrates. Subsequently, Ignavibacterium (3.38% to 2.52%) and Acidovorax (0.46% to 8.83%) conducted biological electricity from electroactive biofilms to suspended sludge. They synergized with dominated genus in suspended sludge, Alicycliphilus (19.56%) that accounted for phenolic oxidation and nitrate reduction. Consequently, the significantly advantage of Geobater and Syntrophorhabdus was the keystone reason for superior biodegradability maintenance of MAC-based MBBR.}, } @article {pmid32334358, year = {2020}, author = {Show, KY and Ling, M and Guo, H and Lee, DJ}, title = {Laboratory and full-scale performances of integrated anaerobic granule-aerobic biofilm-activated sludge processes for high strength recalcitrant paint wastewater.}, journal = {Bioresource technology}, volume = {310}, number = {}, pages = {123376}, doi = {10.1016/j.biortech.2020.123376}, pmid = {32334358}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Paint ; *Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Sustainable treatment of wastewaters generated from paint production is increasingly posing an environmental concern. Recalcitrant paint wastewaters are mostly treated by energy and cost intensive physicochemical methods like incineration, distillation or advanced oxidation. This paper reported for the first time a case study applying biological treatment processes to properly handle a high-strength recalcitrant paint wastewater with 5-day biochemical oxygen demand (BOD5)/chemical oxygen demand (COD) less than 0.02. A biological treatment scheme integrating anaerobic granular sludge blanket reactor, aerobic carrier biofilm reactor and aerobic activated sludge bioreactor was proposed and examined. Laboratory and full-scale trials demonstrated satisfactory operation with overall COD removal up to 99%. Besides yielding consistent effluent quality conforming to the discharge limits, the full-scale plant gained considerable savings in operating cost over a 5-year operation. With proper microbial adaptation and cultivation, as well as adequate reactor and process designs, the scheme offers a good feasibility for efficient and cost-effective treatment of the high strength and recalcitrant paint wastewater.}, } @article {pmid32334259, year = {2020}, author = {Inaba, T and Aoyagi, T and Hori, T and Charfi, A and Suh, C and Lee, JH and Sato, Y and Ogata, A and Aizawa, H and Habe, H}, title = {Clarifying prokaryotic and eukaryotic biofilm microbiomes in anaerobic membrane bioreactor by non-destructive microscopy and high-throughput sequencing.}, journal = {Chemosphere}, volume = {254}, number = {}, pages = {126810}, doi = {10.1016/j.chemosphere.2020.126810}, pmid = {32334259}, issn = {1879-1298}, mesh = {Anaerobiosis ; Bacteria ; Biofilms/growth & development ; Bioreactors/*microbiology ; Eukaryota ; High-Throughput Nucleotide Sequencing ; Membranes ; Membranes, Artificial ; Microbiota ; Microscopy ; Phylogeny ; Prokaryotic Cells ; Sewage ; Solid Waste ; Waste Disposal, Fluid/*methods ; }, abstract = {Anaerobic membrane bioreactor (AnMBR) is used for the treatment of organic solid waste. Clogging of filtration membrane pores, called membrane fouling, is one of the most serious issues for the sustainable operation of AnMBR. Although the physical and chemical mechanisms of the membrane fouling have been widely studied, the biological mechanisms are still unclear. The biofilm formation and development on the membrane might cause the membrane fouling. In this study, the prokaryotic and eukaryotic microbiomes of the membrane-attached biofilms in an AnMBR treating a model slurry of organic solid waste were investigated by non-destructive microscopy and high-throughput sequencing of 16S and 18S rRNA genes. The non-destructive visualization indicated that the biofilm was layered with different structures. The lowermost residual fouling layer was mesh-like and composed of filamentous microorganisms, while the upper cake layer was mainly the non-dense and non-cell region. The principal coordinate and phylogenetic analyses of the sequence data showed that the biofilm microbiomes were different from the sludge. The lowermost layer consisted of operational taxonomic units that were related to Leptolinea tardivitalis and Methanosaeta concilii (9.53-10.07% and 1.14-1.64% of the total prokaryotes, respectively) and Geotrichum candidum (30.22-82.31% of the total eukaryotes), all of which exhibited the filamentous morphology. Moreover, the upper layer was inhabited by the presumably cake-degrading bacteria and predatory eukaryotes. The biofilm microbiome features were consistent with the microscope-visualized structure. These results demonstrated that the biofilm structure and microbiome were the layer specific, which provides better understanding of biological mechanisms of membrane fouling in the AnMBR.}, } @article {pmid32333655, year = {2020}, author = {Hassan, K and Hamdy, O and Helmy, M and Mostafa, H}, title = {Enhancing treated wastewater effluent characteristics using hybrid biofilm/activated sludge process - a case study.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {81}, number = {2}, pages = {217-227}, doi = {10.2166/wst.2020.074}, pmid = {32333655}, issn = {0273-1223}, mesh = {Biofilms ; Bioreactors ; *Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {This paper documents the results of 12 months of monitoring of an upgraded hybrid moving bed biofilm reactor-conventional activated sludge wastewater treatment plant (MBBR-CAS WWTP). It also targets the assessment of the increment of the hydraulic load on existing treatment units with a zero construction and land cost. The influent flow to the plant was increased from 21,000 m[3] d[-1] to 30,000 m[3] d[-1], 40% of the existing CAS reactor volume was used for the MBBR zone with a carrier fill fraction of 47.62% and with Headworks Bio ActiveCell™ 515 used as media; no modifications were made for the primary and secondary tanks. The hybrid reactor showed high removal efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), with average effluent values recording 33.00 ± 8.87 mg L[-1], 52.90 ± 9.65 mg L[-1] and 29.50 ± 6.64 mg L[-1] respectively. Nutrient removals in the hybrid modified biological reactor were moderate compared with carbon removal despite the high C/N ratio of 12.33. Findings in this study favor the application of MBBR in the upgrading of existing CAS plants with the plant BOD5 removal efficiency recording an increase of about 5% compared with the plant before upgrade and effluent values well within the legal requirements.}, } @article {pmid32333442, year = {2020}, author = {Binns, R and Li, W and Wu, CD and Campbell, S and Knoernschild, K and Yang, B}, title = {Effect of Ultraviolet Radiation on Candida albicans Biofilm on Poly(methylmethacrylate) Resin.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {29}, number = {8}, pages = {686-692}, doi = {10.1111/jopr.13180}, pmid = {32333442}, issn = {1532-849X}, support = {//UIC COD Wach Research Fund/ ; }, mesh = {Acrylic Resins ; Biofilms ; *Candida albicans ; *Polymethyl Methacrylate ; Surface Properties ; Ultraviolet Rays ; }, abstract = {PURPOSE: To investigate the effect of 254-nm ultraviolet light on the viability of Candida albicans biofilm on poly(methylmethacrylate).

METHODS: Poly(methylmethacrylate) specimens (1 cm × 1 cm × 1 mm) were placed in 6-well culture plates. Each well contained 8 ml of 10[4] colony forming units/milliliter of C. albicans ATCC90028 and Sabouraud dextrose broth. Plates were incubated at 37°C for 24 hours. Specimens were then divided into 11 groups (n = 4): no treatment control groups, 3.8% sodium perborate immersion for 5 minutes (PP5m) and for 12 hours (PO12h), and 6 groups exposed to ultraviolet light for 5, 15, 30, 60, 120 or 300 seconds separately using UVP XX-15S series lamps. After sonication, cell suspensions were plated, and colony-forming units were counted. The relationship between survival of C. albicans and ultraviolet light irradiation energy exposure was analyzed and compared to the survival of sodium perborate groups. The effect of disinfection treatments and ultraviolet light energy exposure on C. albicans survival was analyzed with ANOVA (alpha = 0.05).

RESULTS: There was a significant decrease in C. albicans survival with increasing ultraviolet light energy exposure (p = 0.00001, p < 0.05) Survival vs. immersion exposure time analysis of chemical disinfection showed no survival of C. albicans in groups PP5m and PO12h. C. albicans in the UV 300s group with energy of 210 mJ/cm[2] (71 CFU/ml) showed a statistical difference from that of two chemical immersion groups (PP5m, PO12h = 0 CFU/ml) (p = 0.00001, p < 0.05).

CONCLUSION: Ultraviolet 254 nm irradiation demonstrated a significant inhibition of C. albicans survival on poly(methylmethacrylate) samples. Ultraviolet light exposure of 300 seconds inhibited the survival of C. albicans close to the level of 3.8% sodium perborate treatment.}, } @article {pmid32332820, year = {2020}, author = {Wang, T and Guo, Z and Shen, Y and Cui, Z and Goodwin, A}, title = {Accumulation mechanism of biofilm under different water shear forces along the networked pipelines in a drip irrigation system.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {6960}, pmid = {32332820}, issn = {2045-2322}, mesh = {Agricultural Irrigation/*instrumentation ; Biofilms/*growth & development ; *Shear Strength ; }, abstract = {The behavior of clogging has a close relationship with the biofilm attached on inner surface of the pipeline in a drip irrigation system using reclaimed water. Therefore, inhibiting biofilm growth is the key to completely addressing the clogging problem. Water shear forces play a vital role in the formation, development and detachment of biofilm. In order to find out the accumulation mechanism of biofilm under different water shear forces, this paper considered 8 different shear forces with a range of [0, 0.7]Pa on the inner surface of pipelines in drip irrigation systems using three kinds of reclaimed water. The results indicate that dry weight (DW), phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) of biofilms show a S-type trend, the maximum contents were observed when τ was 0.2 Pa or 0. 35 Pa. Besides, the influence of water shear forces on biofilms is dual. The formation of biofilm is a dynamic stabilization process. When there is a relatively large shear force, it is favorable to the transport and renewal of microorganisms and nutrients. Meantime, the renewal speed of biofilms is also relatively fast. It is easy to form the biofilms with large surface and small thickness due to relatively high possibility of detachment. When the shear force is small, the transport speed of microorganisms and nutrients are limited, and the ability of microorganisms to secrete polysaccharides is reduced, which makes the nutrients needed for microbial growth insufficient and the adhesion between particles is also reduced, resulting in loose, unstable and an easily removed biofilm structure. After a comprehensive consideration of the dual influence, the critical controlling threshold of internal water shear force was obtained as [0, 0.20] ∪ [0.35, +∞] Pa. In addition, the growth model established in this paper can well describe the growth kinetics of attached biofilms, and provide theoretical reference for monitoring the occurrence of bio-clogging process in drip irrigation systems.}, } @article {pmid32331171, year = {2020}, author = {Ji, MK and Moon, BK and Kim, HS and Park, C and Oh, GJ and Cho, H and Lim, HP}, title = {Assessment of Inhibition of Biofilm Formation on TiO2 Nanotubes According to Non-Thermal Plasma Treatment Conditions and the Elapsed Time in the Atmosphere.}, journal = {Journal of nanoscience and nanotechnology}, volume = {20}, number = {9}, pages = {5742-5745}, doi = {10.1166/jnn.2020.17658}, pmid = {32331171}, issn = {1533-4899}, mesh = {Atmosphere ; Biofilms ; *Nanotubes ; Surface Properties ; *Titanium ; }, abstract = {Periimplantitis is an inflammation similar to periodontitis, and is caused by biofilms formed on the surface of dental implants. Application of plasma on biomaterials has been reported to decrease the initial adhesion of microorganism by causing chemical changes without changing the surface morphology. The purpose of this study is to evaluate the effect of inhibition of biofilm formation on the elapsed time after plasma treatment. Non thermal plasma generator (PGS-200 Plasma generator, Expantech Co., Korea) was applied to the specimens. The elapsed time in the atmosphere was set to 5 immediately after treatment, after 30 minutes of treatment, after 60 minutes of treatment, after 90 minutes of treatment. Surface property change with the elapsed time in the atmosphere after plasma treatment were confirmed by X-ray photoelectron spectroscopy and contact angle. Inhibition of biofilm formation was evaluated by the fluorescent nucleic acid staining. It was confirmed that the chemical composition and bonding state of the surface changes as the elapsed time in the atmosphere increases after plasma treatment. The adhesion of Porphyromonas gingivalis was the lowest immediately after plasma treatment, and increased again with increasing elapsed time in the atmosphere after plasma treatment. As a result of this study, it was confirmed that elapsed time in the atmosphere is a very important factor for inhibition of biofilm formation.}, } @article {pmid32330801, year = {2020}, author = {Ma, J and Wang, K and Gong, H and Yuan, Q and Yang, M and He, C and Shi, C and San, E}, title = {Integrating floc, aggregate and carrier to reap high-quality anammox biofilm.}, journal = {Bioresource technology}, volume = {309}, number = {}, pages = {123325}, doi = {10.1016/j.biortech.2020.123325}, pmid = {32330801}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Chemoautotrophic Growth ; *Nitrogen ; Oxidation-Reduction ; Sewage ; }, abstract = {This work investigated the effects of integration of floc, aggregate and carrier (IFAC) on anammox biofilm quality and development mechanisms. The IFAC system harvested high-quality anammox biofilm with a reduction of 60% in the formation period, an increment of 282.14%~397.26% in mechanical stability, an enhancement of 10.18 ~ 21.56% in ecological stability and an improvement of 9.44%~46.18% in abundance of the phylum Planctomycetes. Aggregates enabled carriers to accumulate initial biomass efficiently and equipped biofilm with additional joint forces. Floc promoted accumulation of terminal biomass, enhanced ecological stability by improving community diversity and raised abundance of the phylum Planctomycetes by assisting anammox consortium settlement. A model of the development procedure of high-quality anammox biofilm was established and a strategy for pre-designing the IFAC system to reap high-quality biofilm was proposed. We expect our findings to provide theoretical guidance for designs and applications of anammox process with excellent stability.}, } @article {pmid32329182, year = {2021}, author = {Huang, Q and Zakaria, BS and Zhang, Y and Zhang, L and Liu, Y and Dhar, BR}, title = {A high-rate anaerobic biofilm reactor for biomethane recovery from source-separated blackwater at ambient temperature.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {1}, pages = {61-74}, doi = {10.1002/wer.1347}, pmid = {32329182}, issn = {1554-7531}, support = {//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Methane ; *Sewage ; Temperature ; }, abstract = {Anaerobic bioreactors for source-separated blackwater are mostly operated at low organic loading rates (OLRs) due to low biodegradability and the potential of ammonia inhibition. In this study, an anaerobic biofilm reactor having conductive carbon fibers as the media was investigated for the high-rate treatment of blackwater collected from vacuum toilets. The bioreactor was operated at different OLRs ranged from 0.77 to 3.01 g COD/L-d in four stages for a total operating period of ~ 250 days. With the increase of OLRs, the specific methane production rate increased from 105.3 to 304.6 ml/L-d with high methane content in biogas (75.5%-83%). The maximum methane yield was achieved at hydraulic retention time (HRT) of 15 days. Highest organics and suspended solids removal (80%-83%) were achieved at 20-days HRT, while increased OLRs resulted in diminished removal efficiencies. The state variables, including pH, total ammonia nitrogen, short-chain volatile fatty acids, and soluble chemical oxygen demand, indicated the system had a great capability to withstand the high OLRs. Microbial community analysis revealed that the high performance might be attributed to direct interspecies electron transfer (DIET) facilitated by potentially electroactive bacteria (e.g., Syntrophomonas, Clostridium) and electrotrophic archaea (e.g., Methanosaeta and Methanosarcina species) enriched on the carbon fibers. PRACTITIONER POINTS: An anaerobic biofilm reactor was investigated for biomethane recovery from source-separated blackwater. Conductive carbon fibers were utilized as the media to stimulate enrichment of potentially electroactive methanogenic communities. The bioreactor was operated at ambient temperature for over 250 days. High methane production rate and high-quality biogas were achieved at OLRs ranged from 0.77 to 3.01 g COD/L-d. Microbial community analysis suggested direct interspecies electron transfer (DIET) between specific electroactive bacteria and electrotrophic archaea.}, } @article {pmid32329166, year = {2020}, author = {Mikolai, C and Kommerein, N and Ingendoh-Tsakmakidis, A and Winkel, A and Falk, CS and Stiesch, M}, title = {Early host-microbe interaction in a peri-implant oral mucosa-biofilm model.}, journal = {Cellular microbiology}, volume = {22}, number = {8}, pages = {e13209}, doi = {10.1111/cmi.13209}, pmid = {32329166}, issn = {1462-5822}, mesh = {Actinomyces/physiology ; *Biofilms ; Cytokines/immunology ; Fibroblasts/immunology/*microbiology ; *Host Microbial Interactions/genetics/immunology ; Humans ; *Models, Anatomic ; Mouth Mucosa/immunology/*microbiology ; Porphyromonas gingivalis/immunology/physiology ; Veillonella/immunology/physiology ; }, abstract = {The host-microbe relationship is pivotal for oral health as well as for peri-implant diseases. Peri-implant mucosa and commensal biofilm play important roles in the maintenance of host-microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host-microbe interaction between commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and organotypic peri-implant mucosa using our three-dimensional model. After 24 hr, biofilms induced weak inflammatory reaction in the peri-implant mucosa by upregulation of five genes related to immune response and increased secretion of IL-6 and CCL20. Biofilm volume was reduced which might be explained by secretion of β-Defensins-1, -2, and CCL20. The specific tissue reaction without intrinsic overreaction might contribute to intact mucosa. Thus, a relationship similar to homeostasis and oral health was established within the first 24 hr. In contrast, the mucosa was damaged and the bacterial distribution was altered after 48 hr. These were accompanied by an enhanced immune response with upregulation of additional inflammatory-related genes and increased cytokine secretion. Thus, the homeostasis-like relationship was disrupted. Such profound knowledge of the host-microbe interaction at the peri-implant site may provide the basis to improve strategies for prevention and therapy of peri-implant diseases.}, } @article {pmid32326756, year = {2020}, author = {Kim, MA and Kim, JH and Nam, OH}, title = {Tea extracts differentially inhibit Streptococcus mutans and Streptococcus sobrinus biofilm colonization depending on the steeping temperature.}, journal = {Biofouling}, volume = {36}, number = {3}, pages = {256-265}, doi = {10.1080/08927014.2020.1755429}, pmid = {32326756}, issn = {1029-2454}, mesh = {Biofilms/*drug effects/growth & development ; Catechin/pharmacology ; Plant Extracts/isolation & purification/*pharmacology ; Streptococcus mutans/*drug effects/growth & development ; Streptococcus sobrinus/*drug effects/growth & development ; Tea/*chemistry ; *Temperature ; }, abstract = {This study aimed to evaluate the effects of tea extracts on oral biofilm colonization depending on steeping temperature. S. mutans and S. sobrinus were cultured and treated with green or black tea extracts prepared under different steeping conditions. Biofilm formation, glucosyltransferase (GTF) levels, bacterial growth, and acidogenicity were evaluated. Biofilms were also assessed by gas chromatography-mass spectrometry and confocal laser scanning microscopy. All extracts with hot steeping showed higher inhibitory effects on biofilm formation and cell viability and lower GTF levels compared with those with cold steeping (p < 0.05). Hot steeping significantly reduced bacterial growth (p < 0.05) and maintained the pH. Catechins were only identified from hot steeping extracts. Within the limits of this study, extracts with cold steeping showed lower inhibitory effects on oral biofilms. The different effects between steeping extracts may be attributed to the difference in catechins released from tea extracts under the different steep conditions.}, } @article {pmid32326753, year = {2020}, author = {Cocco, AR and Cuevas-Suárez, CE and Liu, Y and Lund, RG and Piva, E and Hwang, G}, title = {Anti-biofilm activity of a novel pit and fissure self-adhesive sealant modified with metallic monomers.}, journal = {Biofouling}, volume = {36}, number = {3}, pages = {245-255}, pmid = {32326753}, issn = {1029-2454}, support = {R01 DE027970/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesives/chemistry/*pharmacology ; Animals ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/growth & development ; Dental Caries/microbiology/*prevention & control ; Humans ; Methacrylates/chemistry ; Mice ; Microbiota/drug effects ; Pit and Fissure Sealants/chemistry/*pharmacology ; Streptococcus mutans/drug effects/growth & development ; Streptococcus oralis/drug effects/growth & development ; Zinc/*chemistry ; }, abstract = {Dental plaque is a biofilm composed of a complex oral microbial community. The accumulation of plaque in the pit and fissures of dental elements often leads to the development of tooth decay (dental caries). Here, potent anti-biofilm materials were developed by incorporating zinc methacrylates or di-n-butyl-dimethacrylate-tin into the light-curable sealant and their physical, mechanical, and biological properties were evaluated. The data revealed that 5% di-n-butyl-dimethacrylate-tin (SnM 5%) incorporated sealant showed strong anti-biofilm efficacy against various single-species (Streptococcus mutans or Streptococcus oralis or Candida albicans) and S. mutans-C. albicans cross-kingdom dual-species biofilms without either impairing the mechanical properties of the sealant or causing cytotoxicities against mouse fibroblasts. The findings indicate that the incorporation of SnM 5% in the experimental pit and fissure self-adhesive sealant may have the potential to be part of current chemotherapeutic strategies to prevent the formation of cariogenic oral biofilms that cause dental caries.}, } @article {pmid32326710, year = {2020}, author = {Vašková, S and Slobodníková, L and Fajtl, D and Blažíčková, S and Botek, R and Melicháčová, V}, title = {Biofilm-producing potential of urinary pathogens isolated from chronic and recurrent urinary tract infections and impact of biofilm on gentamicin and colistin in vitro efficacy.}, journal = {Epidemiologie, mikrobiologie, imunologie : casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne}, volume = {69}, number = {1}, pages = {3-9}, pmid = {32326710}, issn = {1210-7913}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteria/drug effects/isolation & purification ; *Bacterial Physiological Phenomena/drug effects ; *Biofilms/drug effects ; Chronic Disease ; *Colistin/pharmacology ; Gentamicins/pharmacology ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; *Urinary Tract Infections/microbiology ; }, abstract = {AIM: The presented study was to compare in vitro biofilm production by bacterial strains from chronic/recurrent and from acute non-complicated UTIs. The activity of gentamicin and colistin on biofilm form of these strains has also been detected, with goal to predict the gentamicin and colistin therapeutic efficacy in the antimicrobial treatment of patients with a suspected presence of biofilm in urinary tract.

MATERIAL AND METHODS: The group of 40 bacterial strains repeatedly isolated from patients with chronic or recurrent UTIs was compared with the group of 40 strains from acute UTIs. Both groups contained comparable number of strains of Escherichia coli, Klebsiella spp., Proteus mirabilis and Pseudomonas aeruginosa. Biofilm production was assessed by method in polystyrene microtiter plate. The MIC and MBC values of gentamicin and colistin were detected by broth microdilution assay. The minimal biofilm inhibitory (MBIC) and biofilm eradication concentrations (MBEC) were tested by microdilution method. Non-inactivated biofilm-associated bacteria were detected after overnight incubation in broth medium free of antimicrobials. The statistical analysis of results was performed by Fisher's exact test and by Student's t-test.

RESULTS: Biofilm was produced by 90% strains from chronic UTIs, but only by 52% of strains from acute UTIs (p = 0.0004). In the biofilm producing strains, the MBIC values of gentamicin reached from four to 256 mg/L, the MBIC levels of colistin from two to 64 mg/L. The minimal biofilm eradicating concentrations were even higher: for gentamicin from eight to > 512 mg/L, and for colistin from 32 to > 512 mg/L. The differences between MIC and MBIC/MBEC levels were statistically highly significant (p < 0.0001). Presumably, the therapeutic success of parenterally applied gentamicin or colistin on biofilm-related urinary tract infections would be, without respect to the high concentration of gentamicin or colistin achievable in urine during parenteral application, rather unpredictable. Local intravesical instillation would allow for achieving higher gentamicin and colistin concentrations; however, there is need for interpretation criteria for MBEC values concerning therapy, as well as for clinical studies allowing for application of those values to predict clinical success of therapy.

CONCLUSIONS: Laboratory detection of biofilm production and evaluation of the MBIC/MBEC values of antimicrobials for strains producing biofilm might be a valuable complement to the microbiologic diagnostics of chronic and recurrent UTIs. It might provide valuable information for more reliable individualised therapy and so decrease the risk of emergence and selection of multiresistant strains during repeated and non-eradicating therapy of chronic and recurrent UTIs.}, } @article {pmid32326407, year = {2020}, author = {Nové, M and Kincses, A and Szalontai, B and Rácz, B and Blair, JMA and González-Prádena, A and Benito-Lama, M and Domínguez-Álvarez, E and Spengler, G}, title = {Biofilm Eradication by Symmetrical Selenoesters for Food-Borne Pathogens.}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32326407}, issn = {2076-2607}, support = {SZTE ÁOK-KKA 2018/270-62-2//Faculty of Medicine, University of Szeged/ ; GINOP-2.3.2-15-2016-00038//Hungary/ ; EFOP 3.6.3-VEKOP-16-2017-00009//Hungary/ ; Iniciativas Ropelanas//Zamora, Spain/ ; Asociación Cultural Trevinca//Zamora, Spain/ ; }, abstract = {Infections caused by Salmonella species and Staphylococcus aureus represent major health and food industry problems. Bacteria have developed many strategies to resist the antibacterial activity of antibiotics, leading to multidrug resistance (MDR). The over-expression of drug efflux pumps and the formation of biofilms based on quorum sensing (QS) can contribute the emergence of MDR. For this reason, the development of novel effective compounds to overcome resistance is urgently needed. This study focused on the antibacterial activity of nine symmetrical selenoesters (Se-esters) containing additional functional groups including oxygen esters, ketones, and nitriles against Gram-positive and Gram-negative bacteria. Firstly, the minimum inhibitory concentrations of the compounds were determined. Secondly, the interaction of compounds with reference antibiotics was examined. The efflux pump (EP) inhibitory properties of the compounds were assessed using real-time fluorimetry. Finally, the anti-biofilm and quorum sensing inhibiting effects of selenocompounds were determined. The methylketone and methyloxycarbonyl selenoesters were the more effective antibacterials compared to cyano selenoesters. The methyloxycarbonyl selenoesters (Se-E2 and Se-E3) showed significant biofilm and efflux pump inhibition, and a methyloxycarbonyl selenoester (Se-E1) exerted strong QS inhibiting effect. Based on results selenoesters could be promising compounds to overcome bacterial MDR.}, } @article {pmid32326022, year = {2020}, author = {Angell, IL and Bergaust, L and Hanssen, JF and Aasen, EM and Rudi, K}, title = {Ecological Processes Affecting Long-Term Eukaryote and Prokaryote Biofilm Persistence in Nitrogen Removal from Sewage.}, journal = {Genes}, volume = {11}, number = {4}, pages = {}, pmid = {32326022}, issn = {2073-4425}, mesh = {Bacteria/*growth & development ; Biofilms/*growth & development ; Bioreactors/*microbiology ; *Denitrification ; Ecology ; Eukaryota/*physiology ; Prokaryotic Cells/*microbiology ; Sewage/*microbiology ; }, abstract = {The factors affecting long-term biofilm stability in sewage treatment remain largely unexplored. We therefore analyzed moving bed bioreactors (MBBRs) biofilm composition and function two years apart from four reactors in a nitrogen-removal sewage treatment plant. Multivariate ANOVA revealed a similar prokaryote microbiota composition on biofilm carriers from the same reactors, where reactor explained 84.6% of the variance, and year only explained 1.5%. Eukaryotes showed a less similar composition with reactor explaining 56.8% of the variance and year 9.4%. Downstream effects were also more pronounced for eukaryotes than prokaryotes. For prokaryotes, carbon source emerged as a potential factor for deterministic assembly. In the two reactors with methanol as a carbon source, the bacterial genus Methylotenera dominated, with M. versatilis as the most abundant species. M. versatilis showed large lineage diversity. The lineages mainly differed with respect to potential terminal electron acceptor usage (nitrogen oxides and oxygen). Searches in the Sequence Read Archive (SRA) database indicate a global distribution of the M. versatilis strains, with methane-containing sediments as the main habitat. Taken together, our results support long-term prokaryote biofilm persistence, while eukaryotes were less persistent.}, } @article {pmid32325685, year = {2020}, author = {Rodrigues, CF and Černáková, L}, title = {Farnesol and Tyrosol: Secondary Metabolites with a Crucial quorum-sensing Role in Candida Biofilm Development.}, journal = {Genes}, volume = {11}, number = {4}, pages = {}, pmid = {32325685}, issn = {2073-4425}, mesh = {Antioxidants/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida/drug effects/*growth & development/metabolism ; Farnesol/*pharmacology ; Phenylethyl Alcohol/*analogs & derivatives/pharmacology ; *Quorum Sensing ; Secondary Metabolism ; }, abstract = {When living in biological and interactive communities, microorganisms use quorum-sensing mechanisms for their communication. According to cell density, bacteria and fungi can produce signaling molecules (e.g., secondary metabolites), which participate, for example, in the regulation of gene expression and coordination of collective behavior in their natural niche. The existence of these secondary metabolites plays a main role in competence, colonization of host tissues and surfaces, morphogenesis, and biofilm development. Therefore, for the design of new antibacterials or antifungals and understanding on how these mechanisms occur, to inhibit the secretion of quorum-sensing (e.g., farnesol and tyrosol) molecules leading the progress of microbial infections seems to be an interesting option. In yeasts, farnesol has a main role in the morphological transition, inhibiting hyphae production in a concentration-dependent manner, while tyrosol has a contrary function, stimulating transition from spherical cells to germ tube form. It is beyond doubt that secretion of both molecules by fungi has not been fully described, but specific meaning for their existence has been found. This brief review summarizes the important function of these two compounds as signaling chemicals participating mainly in Candida morphogenesis and regulatory mechanisms.}, } @article {pmid32325576, year = {2020}, author = {Tian, Z and Palomo, A and Zhang, H and Luan, X and Liu, R and Awad, M and Smets, BF and Zhang, Y and Yang, M}, title = {Minimum influent concentrations of oxytetracycline, streptomycin and spiramycin in selecting antibiotic resistance in biofilm type wastewater treatment systems.}, journal = {The Science of the total environment}, volume = {720}, number = {}, pages = {137531}, doi = {10.1016/j.scitotenv.2020.137531}, pmid = {32325576}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Drug Resistance, Microbial ; Genes, Bacterial ; Oxytetracycline ; Spiramycin ; Streptomycin ; Wastewater ; }, abstract = {It has been demonstrated that antibiotic resistance could be induced and selected under high antibiotic concentrations in biological wastewater treatment systems. However, little is available regarding the minimum concentrations of antibiotics for selecting antibiotic resistance during wastewater treatment. Herein, the minimum influent concentrations of oxytetracycline, streptomycin, and spiramycin in selecting antibiotic resistance in biofilm type wastewater treatment systems were investigated by spiking respective antibiotic into wastewater with an antibiotic dose increasing from 0 to 0.1, 1, 5, 25, 50 mg/L stepwise over a period of 606 days. Significant increase (p < .01) in the total abundance of antibiotic resistance genes was observed for both streptomycin and oxytetracycline at a dose of 0.1 mg/L according to metagenomic sequencing, while the concentration levels leading to significant increases (p < .05) in resistant bacteria ratio were higher: 5 mg/L for streptomycin and 25 mg/L for oxytetracycline. Although resistome abundance increased with the increase of spiramycin dose, neither the corresponding Macrolide-Lincosamide-Streptogramin (MLS) resistance genes nor the resistant bacteria ratio showed perceptible increase. Partial canonical correspondence analysis showed that both bacterial community shift and mobile genetic elements alteration contributed to the enrichment of resistomes under the presence of streptomycin and oxytetracycline. Regarding spiramycin which is mainly targeting on Gram-positive bacteria, the dominance of the intrinsically resisting Gram-negative bacteria in the biofilm microbiota might be responsible for the vague change of MLS resistant determinants under the spiramycin stress. The results demonstrated that it is possible to prevent the development of antibiotic resistance during wastewater treatment by controlling the influent streptomycin and oxytetracyline concentrations below 0.1 mg/L. This work proposed an actionable approach for the management of antibiotic production wastewater.}, } @article {pmid32325511, year = {2020}, author = {Reichling, J}, title = {Anti-biofilm and Virulence Factor-Reducing Activities of Essential Oils and Oil Components as a Possible Option for Bacterial Infection Control.}, journal = {Planta medica}, volume = {86}, number = {8}, pages = {520-537}, doi = {10.1055/a-1147-4671}, pmid = {32325511}, issn = {1439-0221}, mesh = {Anti-Bacterial Agents ; Bacteria ; *Bacterial Infections ; Biofilms ; Chromobacterium ; Humans ; *Oils, Volatile ; Pseudomonas aeruginosa ; Quorum Sensing ; Virulence Factors ; }, abstract = {Pathogenic biofilm-associated bacteria that adhere to biological or nonbiological surfaces are a big challenge to the healthcare and food industries. Antibiotics or disinfectants often fail in an attempt to eliminate biofilms from those surfaces. Based on selected experimental research, this review deals with the potential biofilm-inhibiting, virulence factor-reducing, and biofilm-eradicating activities of essential oils and single essential oil compounds using Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Chromobacterium violaceum as model organisms. In addition, for the bacteria reviewed in this overview, different essential oils and essential oil compounds were reported to be able to modulate the expression of genes that are involved in the formation of autoinducer molecules, biofilms, and virulence factors. The anti-quorum sensing activity of some essential oils and single essential oil compounds was demonstrated using the gram-negative bacterium C. violaceum. Reporter strains of this bacterium produce the violet-colored compound violacein whose synthesis is regulated by quorum sensing autoinducer molecules called acylhomeserinlactones. Of great interest was the discovery that enantiomeric monoterpenes affected the quorum sensing regulation system in different ways. While the (+)-enantiomers of carvone, limonene, and borneol increased violacein formation, their (-)-analogues inhibited violacein production.For the successful eradication of biofilms and the bacteria living inside them, it is absolutely necessary that the lipophilic volatile substances can penetrate into the aqueous channels of biofilms. As shown in recent work, hydrophilic nano-delivery systems encapsulating essential oils/essential oil compounds with antibacterial effects may contribute to overcome this problem.}, } @article {pmid32325482, year = {2020}, author = {Yaban, B and Kikhney, J and Musci, M and Petrich, A and Schmidt, J and Hajduczenia, M and Schoenrath, F and Falk, V and Moter, A}, title = {Aerococcus urinae - A potent biofilm builder in endocarditis.}, journal = {PloS one}, volume = {15}, number = {4}, pages = {e0231827}, pmid = {32325482}, issn = {1932-6203}, mesh = {Aerococcus/*isolation & purification/physiology ; Aged ; Aged, 80 and over ; *Biofilms ; Endocarditis, Bacterial/*diagnosis/*microbiology ; Female ; Heart Valves/*microbiology ; Humans ; In Situ Hybridization, Fluorescence/methods ; Male ; Urinary Tract Infections/microbiology/pathology ; }, abstract = {The diagnosis of infective endocarditis (IE) remains a challenge. One of the rare bacterial species recently associated with biofilms and negative cultures in infective endocarditis is Aerococcus urinae. Whether the low number of reported cases might be due to lack of awareness and misidentification, mainly as streptococci, is currently being discussed. To verify the relevance and biofilm potential of Aerococcus in endocarditis, we used fluorescence in situ hybridization to visualize the microorganisms within the heart valve tissue. We designed and optimized a specific FISH probe (AURI) for in situ visualization and identification of A. urinae in sections of heart valves from two IE patients whose 16S rRNA gene sequencing had deteced A. urinae. Both patients had a history of urinary tract infections. FISH visualized impressive in vivo grown biofilms in IE, thus confirming the potential of A. urinae as a biofilm pathogen. In both cases, FISH/PCR was the only method to unequivocally identify A. urinae as the only causative pathogen for IE. The specific FISH assay for A. urinae is now available for further application in research and diagnostics. A. urinae should be considered in endocarditis patients with a history of urinary tract infections. These findings support the biofilm potential of A. urinae as a virulence factor and are meant to raise the awareness of this pathogen.}, } @article {pmid32325345, year = {2020}, author = {Faille, C and Brauge, T and Leleu, G and Hanin, A and Denis, C and Midelet, G}, title = {Comparison of the performance of the biofilm sampling methods (swab, sponge, contact agar) in the recovery of Listeria monocytogenes populations considering the seafood environment conditions.}, journal = {International journal of food microbiology}, volume = {325}, number = {}, pages = {108626}, doi = {10.1016/j.ijfoodmicro.2020.108626}, pmid = {32325345}, issn = {1879-3460}, mesh = {Agar ; Animals ; Azides/chemistry ; Biofilms/*growth & development ; Carnobacterium/isolation & purification ; Disinfectants/pharmacology ; Europe ; Fishes/microbiology ; Food Microbiology/*methods ; Listeria monocytogenes/*isolation & purification ; Propidium/analogs & derivatives/chemistry ; Pseudomonas fluorescens/isolation & purification ; Seafood/*microbiology ; Stainless Steel/analysis ; }, abstract = {AIMS: The aim of this study was to evaluate the performance of sampling methods [contact plates, sponges, and swabs] in the recovery of biofilm Listeria monocytogenes populations considering the seafood environment conditions (nature of conditioning, of materials and bacterial species).

METHODS AND RESULTS: Different materials (stainless steel, polyvinyl chloride, polyurethane) were conditioned with two fish filtrates, the ready-to-eat the most consumed in Europe (smoked salmon, cod). After, we added the suspension of Listeria monocytogenes, alone or with Pseudomonas fluorescens or Carnobacterium strains, and incubated for 48 h at 8 °C. Then, the 48 h-biofilms were sampled with different methods (contact plates, sponges, and swabs). The cultivable bacterial populations were enumerated on agar, while the L. monocytogenes total and viable populations were quantified by qPCR and propidium monoazide-qPCR (PMA-qPCR), respectively. The amount of L. monocytogenes in biofilms was affected only by the nature of the conditioning with lowest adherent bacteria with cod versus with smoked salmon conditioning. Considering the amount of total population, the swab displayed the lowest values versus the sponges and the contact plates. An explanation was that the observations of the swab by microscopy showed the bacteria trapped within it. The recovery of cultivable bacterial populations was not significantly different with the three sampling methods. On the contrary, we showed that the VBNC populations were only detached by two of three methods (contact plates, sponges) while for the dead populations, those were contact plates and swabs.

CONCLUSIONS: The nature of the conditioning influenced the amount of the bacteria in biofilms. And the performance of the recovery of the bacterial populations (dead, VBNC, cultivable) was dependent on the methods used.

This study showed that the seafood environmental conditions influenced the biofilm formation and the assessment of the efficiency of cleaning and disinfectant operations could be significantly affected by the used sampling methods.}, } @article {pmid32325265, year = {2020}, author = {Dezhurko-Korol, VA and Novozhilova, NE and Makeeva, IM and Arkhipova, AY and Moisenovich, MM and Akhmadishina, LV and Lukashev, AN and Semenov, AM and Leontieva, MR and Byakova, SF}, title = {The influence of centrifugation and inoculation time on the number, distribution, and viability of intratubular bacteria and surface biofilm in deciduous and permanent bovine dentin.}, journal = {Archives of oral biology}, volume = {114}, number = {}, pages = {104716}, doi = {10.1016/j.archoralbio.2020.104716}, pmid = {32325265}, issn = {1879-1506}, mesh = {Animals ; *Biofilms ; Cattle ; *Centrifugation ; Dentin/*microbiology ; *Enterococcus faecalis ; *Microbial Viability ; Microscopy, Electron, Scanning ; Tooth, Deciduous/microbiology ; }, abstract = {UNLABELLED: The present study aimed to assess the influence of centrifugation and inoculation time on the number, distribution, and viability of intratubular bacteria and surface monospecies E. faecalis biofilm.

MATERIALS AND METHODS: Forty-four semicylindrical specimens cut from primary (n = 22) and permanent (n = 22) bovine teeth were randomly assigned to the experimental groups. Teeth of each type were inoculated with E. faecalis with and without centrifugation for 1 and 14 days. The number, localization, viability of bacteria and depth of their penetration were assessed with bacterial culturing of dentin shavings, scanning electron microscopy (SEM) and confocal laser electron microscopy (CLSM). Three-way ANOVA with post-hoc Tukey test were used to assess the influence of different experimental setups on dentin infection.

RESULTS: Severe dentin infection was observed in permanent and deciduous teeth after centrifugation and 1-day incubation: bacteria reached the full length of dentinal tubules and colony-forming units were too numerous to count. The volume of green fluorescence didn't differ significantly in permanent teeth compared with deciduous (p = 1.0). After 1-day stationary inoculation, small number of cultivable bacteria and few viable bacteria in dentinal tubules were found in both groups. After 14-day stationary inoculation, the dentin infection according to CLSM was deeper in deciduous teeth compared with permanent (p = 0.006 and p = 0.019 for centrifugation and stationary inoculation, respectively).

CONCLUSION: The most even and dense dentin infection was observed in primary and permanent bovine teeth after centrifugation and 1-day inoculation, and in deciduous teeth after 14-day stationary inoculation.}, } @article {pmid32324227, year = {2020}, author = {Vaňková, E and Kašparová, P and Dulíčková, N and Čeřovský, V}, title = {Combined effect of lasioglossin LL-III derivative with azoles against Candida albicans virulence factors: biofilm formation, phospholipases, proteases and hemolytic activity.}, journal = {FEMS yeast research}, volume = {20}, number = {3}, pages = {}, doi = {10.1093/femsyr/foaa020}, pmid = {32324227}, issn = {1567-1364}, mesh = {Antifungal Agents/*pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis/*pharmacokinetics ; Azoles/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects ; Erythrocytes/drug effects ; Hemolysis/*drug effects ; Humans ; Hydrophobic and Hydrophilic Interactions/drug effects ; Peptide Hydrolases/*metabolism ; Phospholipases/*antagonists & inhibitors ; Virulence Factors ; }, abstract = {Candida albicans has several virulence factors at its disposal, including yeast-hyphal transition associated with biofilm formation, phospholipases, proteases and hemolytic activity, all of which contribute to its pathogenesis. We used synthetic derivative LL-III/43 of antimicrobial peptide lasioglossin LL-III to enhance effect of azoles on attenuation of C. albicans virulence factors. LL-III/43 was able to inhibit initial adhesion or biofilm formation of C. albicans strains at 50 µM. Azoles, however, were ineffective at this concentration. Using fluorescently labeled LL-III/43, we observed that peptide covered C. albicans cells, partially penetrated through their membranes and then accumulated inside cells. LL-III/43 (25 µM) in combination with clotrimazole prevented biofilm formation already at 3.1 µM clotrimazole. Neither LL-III/43 nor azoles were able to significantly inhibit phospholipases, proteases, or hemolytic activity of C. albicans. LL-III/43 (25 µM) and clotrimazole (50 µM) in combination decreased production of these virulence factors, and it completely attenuated its hemolytic activity. Scanning electron microscopy showed that LL-III/43 (50 µM) prevented C. albicans biofilm formation on Ti-6Al-4 V alloy used in orthopedic surgeries and combination of LL-III/43 (25 µM) with clotrimazole (3.1 µM) prevented biofilm formation on urinary catheters. Therefore, mixture of LL-III/43 and clotrimazole is suitable candidate for future pharmaceutical research.}, } @article {pmid32322819, year = {2020}, author = {Permana, AD and Mir, M and Utomo, E and Donnelly, RF}, title = {Bacterially sensitive nanoparticle-based dissolving microneedles of doxycycline for enhanced treatment of bacterial biofilm skin infection: A proof of concept study.}, journal = {International journal of pharmaceutics: X}, volume = {2}, number = {}, pages = {100047}, pmid = {32322819}, issn = {2590-1567}, support = {/WT_/Wellcome Trust/United Kingdom ; }, abstract = {The presence of bacterial biofilms in wounds is a main issue in the healing process. Conventional therapy of bacterial biofilms is hampered by the poor penetration of antibacterial agents through the physical barrier on the infected skin and the non-specific target of antibacterial agents. Here, we present a combination approach of bacterial sensitive nanoparticles (NPs) and dissolving microneedles (MNs) of doxycycline (DOX) for improved biofilm penetration and specifically delivering DOX to the infection site. The NPs were prepared from poly(lactic-co-glycolic acid) and poly (Ɛ-caprolactone) decorated with chitosan. The release of DOX was improved with the presence of bacterial producing biofilm up to 7-fold. The incorporation of these NPs into dissolving MNs was able to significantly enhance the dermatokinetic profiles of DOX, indicated by higher retention time compared to needle-free patches. Importantly, the antibiofilm activity in ex vivo biofilm model showed that after 48 h, the bacterial bioburdens decreased up to 99.99% following the application of this approach. The results presented here assist as proof of principle for the improvement of dermatokinetic profiles and antibiofilm activities of DOX, following its formulation into bacterial sensitive NPs and delivery via MN. Future studies must explore in vivo efficacy in a suitable animal model.}, } @article {pmid32322380, year = {2020}, author = {Shayesteh, F and Ahmad, A and Usup, G}, title = {In vitro anti-biofilm activity of bacteriocin from a marine Bacillus sp. strain Sh10 against Proteus mirabilis.}, journal = {Iranian journal of microbiology}, volume = {12}, number = {1}, pages = {52-61}, pmid = {32322380}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Biofilm formed by Proteus mirabilis strains is one of the most important medical problems especially in the case of device-related urinary tract infections. This study was conducted to evaluate the bacteriocin produced by a marine isolate of Bacillus sp. Sh10, for it's in vitro inhibitory activity against pre-formed biofilm and in interference with the biofilm-forming of two biofilm-producing bacteria (P. mirabilis UCa4 and P. mirabilis UCe1).

MATERIALS AND METHODS: Sensitivity of two biofilm-producing bacteria (P. mirabilis UCa4 and P. mirabilis UCe1) to bacteriocin, was investigated in planktonic and biofilm states by cell viability and crystal violet assay, respectively. Scanning electron microscopy (SEM) was also performed to determine the effect of bacteriocin on the morphology of the cells associated with biofilm.

RESULTS: It was found that bacteriocin possessed bactericidal activity to biofilm-forming isolates in the planktonic state. However, bacteriocin interferes with the formation of biofilms and disrupts established biofilms. Bacteriocin reduced biofilm formation in the isolates of P. mirabilis UCa4 and P. mirabilis UCe1 with SMIC50 of 32 and 128 μg/mL, desirable SMIC50 of bacteriocin for biofilm disruption were 128 and 256 μg/mL, respectively. The SEM results indicated that bacteriocin affected the cell morphology of biofilm-associated cells.

CONCLUSION: The present findings indicated that bacteriocin from Bacillus sp. Sh10 has bactericidal properties against biofilm-forming isolates of P. mirabilis UCa4 and P. mirabilis UCe1 and has the ability to inhibit the formation of biofilm and disrupt established biofilm.}, } @article {pmid32321490, year = {2020}, author = {Kruse, AB and Maamar, R and Akakpo, DL and Woelber, JP and Wittmer, A and Vach, K and Ratka-Krüger, P and Al-Ahmad, A}, title = {Effects of subgingival air-polishing with trehalose powder on oral biofilm during periodontal maintenance therapy: a randomized-controlled pilot study.}, journal = {BMC oral health}, volume = {20}, number = {1}, pages = {123}, pmid = {32321490}, issn = {1472-6831}, support = {ZVS20140127//Duerr Dental SE/International ; }, mesh = {Adult ; Aged ; Biofilms/*drug effects ; Dental Plaque/microbiology/*therapy ; Dental Scaling/*instrumentation ; Female ; Humans ; Male ; Middle Aged ; Outcome and Process Assessment, Health Care ; Periodontal Pocket/*drug therapy/prevention & control ; Pilot Projects ; Powders ; Trehalose/*pharmacology/therapeutic use ; }, abstract = {BACKGROUND: This pilot study was part of a larger study which compared the effect of subgingival air-polishing using trehalose powder with sonic scaling on clinical parameters during supportive periodontal therapy. Within this microbiological part of the investigation subgingival samples were taken from 10 participants to analyze the survival of different bacterial species after the two different treatments as a proof of principle.

METHODS: In 10 participants two non-adjacent, single-root teeth requiring treatment (PD =5 mm with bleeding on probing (BOP) or > 5 mm) were selected following a split-mouth design and were treated either with a sonic scaler or air-polishing device and trehalose powder. For persistent pockets (PD =4 mm and BOP or > 4 mm), treatment was repeated after 3 months. Subgingival biofilm samples were taken at baseline (BL), subsequently and three and six months after treatment. After determination of the bacterial counts (TBL), isolated bacteria were identified by MALDI-TOF-MS. If unsuccessful, PCR and 16S rDNA sequencing were performed.

RESULTS: In both treatment groups, TBL decreased immediately after treatment remaining at a lower level. This confirms the findings of the larger study regarding clinical parameters showing a comparable effect on PD, BOP and CAL. Immediately after treatment, the diversity of detected species decreased significantly more than in the sonic group (p = 0.03). After 3 months, the proportion of Gram-positive anaerobic rods was lower in the air-polishing group (powder/ sonic 7%/ 25.9%, p = 0.025). Also, there was a greater reduction of Gram-negative aerobic rods for this group at this time (air-polishing/ sonic - 0.91 / -0.23 Log10 cfu/ ml, p = 0.020).

CONCLUSION: Within the limitations of this study air-polishing and sonic treatment seem to have a comparable effect on the subgingival oral biofilm during supportive periodontal treatment.

TRIAL REGISTRATION: The study was registered in an international trial register (German Clinical Trial Register number DRKS 00006296) on 10th of June 2015. HTML&TRIAL_ID = DRKS00006296.}, } @article {pmid32321306, year = {2020}, author = {Marques, DM and Oliveira, VC and Souza, MT and Zanotto, ED and Issa, JPM and Watanabe, E}, title = {Biomaterials for orthopedics: anti-biofilm activity of a new bioactive glass coating on titanium implants.}, journal = {Biofouling}, volume = {36}, number = {2}, pages = {234-244}, doi = {10.1080/08927014.2020.1755842}, pmid = {32321306}, issn = {1029-2454}, mesh = {Biocompatible Materials/*chemistry ; Biofilms/*growth & development ; Candida albicans/growth & development ; Glass/*chemistry ; Prostheses and Implants/*microbiology ; Pseudomonas aeruginosa/growth & development ; Staphylococcus epidermidis/growth & development ; Surface Properties ; Titanium/*chemistry ; }, abstract = {This study evaluated adhesion and biofilm formation by Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis on surfaces of titanium (Ti) and titanium coated with F18 Bioactive Glass (BGF18). Biofilms were grown and the areas coated with biofilm were determined after 2, 4 and 8 h. Microscopy techniques were applied in order to visualize the structure of the mature biofilm and the extracellular matrix. On the BGF18 specimens, there was less biofilm formation by C. albicans and S. epidermidis after incubation for 8 h. For P. aeruginosa biofilm, a reduction was observed after incubation for 4 h, and it remained reduced after 8 h on BGF18 specimens. All biofilm matrices seemed to be thicker on BGF18 surface than on titanium surfaces. BGF18 showed significant anti-biofilm activity in comparison with Ti in the initial periods of biofilm formation; however, there was extensive biofilm after incubation for 48 h.}, } @article {pmid32320601, year = {2020}, author = {Li, Q and Tan, L and Wang, H and Kou, Y and Shi, X and Zhang, S and Pan, Y}, title = {Fusobacterium nucleatum Interaction with Pseudomonas aeruginosa Induces Biofilm-Associated Antibiotic Tolerance via Fusobacterium Adhesin A.}, journal = {ACS infectious diseases}, volume = {6}, number = {7}, pages = {1686-1696}, doi = {10.1021/acsinfecdis.9b00402}, pmid = {32320601}, issn = {2373-8227}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Fusobacterium ; *Fusobacterium nucleatum ; Humans ; *Pseudomonas aeruginosa ; }, abstract = {Respiratory infections with Pseudomonas aeruginosa or Fusobacterium nucleatum are associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and failure in antibiotic treatment. However, the impact of these dual-species interactions on the severity of chronic obstructive pulmonary disease (COPD) and biofilm antibiotic susceptibility remains poorly understood. This study demonstrated that F. nucleatum frequently coexisted with P. aeruginosa in the respiratory tract, and the number of F. nucleatum was negatively correlated with the lung function of AECOPD patients. The coculture of P. aeruginosa and F. nucleatum promoted bacterial proliferation and induced antibiotic tolerance through the formation of a dense biofilm surrounded by excessive Pel and Psl polysaccharides. Moreover, Fusobacterium adhesin A (FadA), rather than F. nucleatum spent medium, induced antibiotic tolerance of the P. aeruginosa biofilm. These results indicate that F. nucleatum is a biomarker of lung function decline in AECOPD patients and interacts with P. aeruginosa in vitro to resist antibiotics via FadA, which would be a potential anti-infective target of these dual-species infection.}, } @article {pmid32320228, year = {2020}, author = {Gao, Y and Wang, J and Chai, M and Li, X and Deng, Y and Jin, Q and Ji, J}, title = {Size and Charge Adaptive Clustered Nanoparticles Targeting the Biofilm Microenvironment for Chronic Lung Infection Management.}, journal = {ACS nano}, volume = {14}, number = {5}, pages = {5686-5699}, doi = {10.1021/acsnano.0c00269}, pmid = {32320228}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Azithromycin/pharmacology ; *Biofilms ; Lung ; *Nanoparticles ; }, abstract = {Chronic lung infection caused by bacterial biofilms is an extremely serious clinical problem, which can lead to the failure of antibiotic therapy. Although nanoparticles have shown great potential in the treatment of biofilms, the efficient penetration and retention of nanoparticles in biofilms is still a big challenge. To address this issue, we herein fabricate size and charge adaptive azithromycin (AZM)-conjugated clustered nanoparticles (denoted as AZM-DA NPs) as therapeutic agents for treating biofilms. The AZM-DA NPs are prepared by electrostatic complexation between AZM conjugated amino-ended poly(amidoamine) dendrimer (PAMAM) and 2,3-dimethyl maleic anhydride (DA) modified poly(ethylene glycol)-block-polylysine (PEG-b-PLys). It is noteworthy that the AZM-DA NPs can disassemble in an acidic biofilm microenvironment (pH 6.0), leading to the release of secondary AZM-conjugated PAMAM nanoparticles (PAMAM-AZM NPs). PAMAM-AZM NPs with small size and positive charge are beneficial for improved penetration and retention inside biofilms, enhanced permeabilization of the bacterial membrane, and increased internalization of AZM, thus exhibiting excellent antibiofilm activities. AZM-DA NPs are also favorable as long-term antibacterial agents due to the reduced occurrence of drug resistance. In vivo therapeutic performance is confirmed by the reduced bacterial burden and the alleviated inflammation in the chronic lung infection model. This research not only develops an innovative strategy for antibiotic delivery in vivo but also provides an effective way for the management of biofilm-associated infections, including chronic lung infection.}, } @article {pmid32320095, year = {2020}, author = {Oda, M and Kurosawa, M and Yamamoto, H and Domon, H and Takenaka, S and Ohsumi, T and Maekawa, T and Yamasaki, N and Furue, Y and Terao, Y}, title = {Sulfated vizantin inhibits biofilm maturation by Streptococcus mutans.}, journal = {Microbiology and immunology}, volume = {64}, number = {7}, pages = {493-501}, doi = {10.1111/1348-0421.12797}, pmid = {32320095}, issn = {1348-0421}, support = {26293390//Japan Society for the Promotion of Science/ ; 26305034//Japan Society for the Promotion of Science/ ; 26670816//Japan Society for the Promotion of Science/ ; 15H05017//Japan Society for the Promotion of Science/ ; 18H02657//Japan Society for the Promotion of Science/ ; AS2531332Q//Adaptable and Seamless Technology Transfer Program through Target-Driven R and D/ ; //JSPS KAKENHI/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/*growth & development ; Cell Line ; Dental Caries/microbiology/prevention & control ; Glucosyltransferases/antagonists & inhibitors/metabolism ; Glycolipids/*pharmacology ; Humans ; Streptococcus mutans/*drug effects/*growth & development ; Sulfates/chemistry ; Trehalose/*analogs & derivatives/pharmacology ; Virulence Factors/metabolism ; }, abstract = {Streptococcus mutans is the main pathogen of dental caries and adheres to the tooth surface via soluble and insoluble glucans produced by the bacterial glucosyltransferase enzyme. Thus, the S. mutans glucosyltransferase is an important virulence factor for this cariogenic bacterium. Sulfated vizantin effectively inhibits biofilm formation by S. mutans without affecting its growth. In this study, less S. mutans biofilm formation occurred on hydroxyapatite discs coated with sulfated vizantin than on noncoated discs. Sulfated vizantin showed no cytotoxicity against the human gingival cell line Ca9-22. Sulfated vizantin dose-dependently inhibited the extracellular release of cell-free glucosyltransferase from S. mutans and enhanced the accumulation of cell-associated glucosyltransferase, compared with that observed with untreated bacteria. Sulfated vizantin disrupted the localization balance between cell-associated glucosyltransferase and cell-free glucosyltransferase, resulting in inhibited biofilm maturation. These results indicate that sulfated vizantin can potentially serve as a novel agent for preventing dental caries.}, } @article {pmid32318864, year = {2020}, author = {Iseppi, R and Sabia, C and Bondi, M and Mariani, M and Messi, P}, title = {Virulence Factors, Drug Resistance and Biofilm Formation in Pseudomonas Species Isolated from Healthcare Water Systems.}, journal = {Current microbiology}, volume = {77}, number = {8}, pages = {1737-1745}, pmid = {32318864}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion ; Biofilms/*growth & development ; *Drug Resistance, Multiple, Bacterial ; Glass ; Hospitals ; Italy ; Microbial Sensitivity Tests ; Polystyrenes ; Pseudomonas/classification/*drug effects/*pathogenicity ; *Virulence Factors ; *Water Microbiology ; *Water Supply ; }, abstract = {Pseudomonas aeruginosa is a frequent causative agent of healthcare-associated diseases, but recently, other members of the Pseudomonas genus have been recognized to cause human colonization and infection. Since the aquatic environment could be an important source of contamination, we studied the drug resistance and virulence profiles in Pseudomonas species isolated from healthcare water systems. 17 Pseudomonas spp. out of 57 were randomly selected and their drug resistance and virulence profiles were later evaluated. Based on the positivity to the tests, the adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 6 strains, each belonging to different species. Six Pseudomonas strains (35%) were α-hemolytic, nine (53%) showed a positivity to the gelatinase test, and P. acidovorans 2R only was capable to degrade DNA. All Pseudomonas strains presented urease activity and the production of siderophores was widely observed (64,7%). Most of the strains showed one of the three types of motilities, 15 Pseudomonas (88.23%) resulted bacteriocin producers and all strains were resistant to one or more antibiotics. Lastly, among the six selected strains, P. aeruginosa 98.5 and P. fluorescens 97.4 were the best biofilm producers. Our study has highlighted how the majority of isolates shows biological characteristics that contribute to the pathogenicity of Pseudomonas. These features emphasize the virulence potentiality of other members of the Pseudomonas genus besides Pseudomonas aeruginosa, making them potentially pathogenic, especially against immunocompromised individuals.}, } @article {pmid32318110, year = {2020}, author = {Diriba, K and Kassa, T and Alemu, Y and Bekele, S}, title = {In Vitro Biofilm Formation and Antibiotic Susceptibility Patterns of Bacteria from Suspected External Eye Infected Patients Attending Ophthalmology Clinic, Southwest Ethiopia.}, journal = {International journal of microbiology}, volume = {2020}, number = {}, pages = {8472395}, pmid = {32318110}, issn = {1687-918X}, abstract = {BACKGROUND: Ocular disease with its complications is a major public health problem which has significant impacts on the quality of life particularly in developing countries. An eye infection due to bacterial agents can lead to reduced vision and blindness. This study was aimed to assess the antimicrobial susceptibility pattern and biofilm-forming potential of bacteria isolated from suspected external eye infected patients in Jimma.

METHOD: A cross-sectional facility-based study was conducted on 319 suspect patients with external eye infections from March to June 2017 at Jimma University Medical Center (JUMC) Ophthalmology Department in Ethiopia. External ocular specimens were collected and standard operating procedures were followed to handle and culture throughout the study period. Antimicrobial susceptibility was determined by the disk diffusion method according to CLSI guidelines. Microtiter (96 wells) plate method was used to screen biofilm formation by ELISA reader at 570 nm.

RESULTS: Out of 319 study participants with an external eye infection, the prevalence of bacterial pathogens was 46.1%. The predominant bacterial isolates were coagulase-negative staphylococcus (CoNS) (27.7%) followed by Staphylococcus aureus (19.7%). Among Gram-negative groups, Pseudomonas aeruginosa (6.8%) was the leading isolate. Increased antimicrobial resistance was observed for tetracycline (64%), erythromycin (66.7%), and penicillin (77.1%). Amoxicillin-clavulanic acid, ciprofloxacin, and gentamicin were the most effective drugs for external eye infections due to susceptibility ranging from 70 to 100% among both Gram-negative and Gram-positive groups. Methicillin-resistant S. aureus (MRSA) accounted for 13.8%. Multidrug resistance (MDR) accounted for 68.7%. The overall biofilm formation rate of bacterial ocular pathogens was 66.1%, where P. aeruginosa (40%), CoNS (34.1%), and S. aureus (31%) formed strong biofilm phenotype.

CONCLUSION: The prevalence rate of bacterial isolates was high. Almost all bacterial isolates were resistant to at least one or more drugs. MDR pathogens were observed increasingly among biofilm formers or vice versa.}, } @article {pmid32316415, year = {2020}, author = {Sheng, H and Xue, Y and Zhao, W and Hovde, CJ and Minnich, SA}, title = {Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle.}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32316415}, issn = {2076-2607}, support = {P20GM103408//Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under Grant #P20GM103408/ ; IDAO1467//Agricultural Research Service/ ; IDAO1406//Agricultural Research Service/ ; }, abstract = {Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.}, } @article {pmid32316222, year = {2020}, author = {Sampedro, I and Pérez-Mendoza, D and Toral, L and Palacios, E and Arriagada, C and Llamas, I}, title = {Effects of Halophyte Root Exudates and Their Components on Chemotaxis, Biofilm Formation and Colonization of the Halophilic Bacterium Halomonas Anticariensis FP35[T].}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32316222}, issn = {2076-2607}, support = {RYC-2014-15532//Ministerio de Economía, Industria y Competitividad, Gobierno de España/ ; }, abstract = {Increase in soil salinity poses an enormous problem for agriculture and highlights the need for sustainable crop production solutions. Plant growth-promoting bacteria can be used to boost the growth of halophytes in saline soils. Salicornia is considered to be a promising salt-accumulating halophyte for capturing large amounts of carbon from the atmosphere. In addition, colonization and chemotaxis could play an important role in Salicornia-microbe interactions. In this study, the role of chemotaxis in the colonization of the halophilic siredophore-producing bacteria, Halomonas anticariensis FP35[T], on Salicornia hispanica plants was investigated. The chemotactic response of FP35[T] to Salicornia root exudates showed optimum dependence at a salt concentration of 5 % NaCl (w/v). Oleanolic acid, the predominant compound in the exudates detected by HPLC and identified by UPLC-HRMS Q-TOF, acts as a chemoattractant. In vitro experiments demonstrated the enhanced positive effects of wild-type H. anticariensis strain FP35[T] on root length, shoot length, germination and the vigour index of S. hispanica. Furthermore, these positive effects partially depend on an active chemotaxis system, as the chemotaxis mutant H. anticariensis FP35 ΔcheA showed reduced plant growth promotion for all the parameters tested. Overall, our results suggest that chemotaxis responses to root exudates play an important role in interactions between Salicornia and halophilic bacteria, enhance their colonization and boost plant growth promotion. Preliminary results also indicate that root exudates have a positive impact on H. anticariensis FP35[T] biofilm formation under saline conditions, an effect which totally depends on the presence of the cheA gene.}, } @article {pmid32315795, year = {2020}, author = {Chen, Z and Zhang, X and Ma, Y and Song, Y and Li, Y and Geng, G and Huang, Y}, title = {Anammox biofilm system under the stress of Hg(II): Nitrogen removal performance, microbial community dynamic and resistance genes expression.}, journal = {Journal of hazardous materials}, volume = {395}, number = {}, pages = {122665}, doi = {10.1016/j.jhazmat.2020.122665}, pmid = {32315795}, issn = {1873-3336}, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Mercury/toxicity ; *Microbiota ; Nitrogen/analysis ; Oxidation-Reduction ; Sewage ; }, abstract = {The existence of heavy metals in wastewater has obtained more attention due to its high toxicity and non-degradability. In this study, we investigated the changes of anaerobic ammonium oxidation (Anammox) system under long-term invasion of Hg(Ⅱ). The results indicated that the total nitrogen removal efficiency (TNRE) dropped to around 55 % as Hg(Ⅱ) concentration went up to 20 mg L[-1]. But the functional bacteria rapidly developed some resistant abilities and maintained a stable TNRE of 65 % till the end of test. The maximum relative expression fold change of merA, merB, merD and merR were 468.8476, 23.7383, 5.0321 and 15.2514 times, respectively. The high positive correlation between the expression abundance of metal resistance genes and the concentrations of Hg(Ⅱ) revealed the resistant mechanisms of microorganisms to heavy metals. Moreover, the protective strategy based on extracellular polymeric substances also contributed to the stability of Anammox system.}, } @article {pmid32315688, year = {2020}, author = {Gumus, B and Acar, T and Atabey, T and Derman, S and Sahin, F and Arasoglu, T}, title = {The battle against biofilm infections: juglone loaded nanoparticles as an anticandidal agent.}, journal = {Journal of biotechnology}, volume = {316}, number = {}, pages = {17-26}, doi = {10.1016/j.jbiotec.2020.04.009}, pmid = {32315688}, issn = {1873-4863}, mesh = {Antifungal Agents/*administration & dosage/chemistry ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Drug Liberation ; Nanoparticles/*administration & dosage/chemistry ; Naphthoquinones/*administration & dosage/chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer/*administration & dosage/chemistry ; }, abstract = {In this study, juglone nanoparticles were prepared by single emulsion solvent evaporation method and their effect against Candida albicans biofilm was investigated in comparison with the free juglone and Fluconazole by performing XTT, crystal violet, standard plate count, confocal microscopy and membrane depolarization analyses. Juglone nanoparticles and free juglone were found to inhibit biofilm formation and pre-established biofilms (98-100%) at all doses tested, whereas Fluconazole did not cause a significant inhibition, even at the highest dose applied, especially against pre-established biofilms. Membrane depolarization analysis showed that free juglone and juglone loaded nanoparticles were effective on C. albicans membrane structure and have fluorescence quenching effect on DiSC3(5). It is extremely important that the antibiofilm activity of the juglone nanoparticles is similar to that of the juglone used at the same concentration, since similar effect is provided by using less active substance due to controlled release. Accordingly, it can easily be said that juglone loaded nanoparticles are much more effective in the formation and elimination of C. albicans biofilm than the free juglone and Fluconazole.}, } @article {pmid32309695, year = {2020}, author = {Ahmed, B and Ameen, F and Rizvi, A and Ali, K and Sonbol, H and Zaidi, A and Khan, MS and Musarrat, J}, title = {Destruction of Cell Topography, Morphology, Membrane, Inhibition of Respiration, Biofilm Formation, and Bioactive Molecule Production by Nanoparticles of Ag, ZnO, CuO, TiO2, and Al2O3 toward Beneficial Soil Bacteria.}, journal = {ACS omega}, volume = {5}, number = {14}, pages = {7861-7876}, pmid = {32309695}, issn = {2470-1343}, abstract = {The unregulated discharge of nanoparticles (NPs) from various nanotechnology industries into the environment is expected to alter the composition and physiological functions of soil microbiota. Considering this knowledge gap, the impact of five NPs (Ag, ZnO, CuO, Al2O3, and TiO2) differing in size and morphology on growth behavior and physiological activity of Azotobacter chroococcum, Bacillus thuringiensis, Pseudomonas mosselii, and Sinorhizobium meliloti were investigated. Various biochemical and microscopic approaches were adopted. Interestingly, all bacterial strains were found sensitive to Ag-NPs and ZnO-NPs but showed tolerance toward CuO, Al2O3, and TiO2-NPs. The loss of cellular respiration due to NPs was coupled with a reduction in population size. ZnO-NPs at 387.5 μg mL[-1] had a maximum inhibitory impact on A. chroococcum and reduced its population by 72%. Under Ag-NP stress, the reduction in IAA secretion by bacterial strains followed the order S. meliloti (74%) > P. mosselii (63%) > A. chroococcum (49%). The surface of bacterial cells had small- or large-sized aggregates of NPs. Also, numerous gaps, pits, fragmented, and disorganized cell envelopes were visible. Additionally, a treated cell surface appeared corrugated with depressions and alteration in cell length and a strong heterogeneity was noticed under atomic force microscopy (AFM). For instance, NPs induced cell roughness for P. mosselii followed the order 12.6 nm (control) > 58 nm (Ag-NPs) > 41 nm (ZnO-NPs). TEM analysis showed aberrant morphology, cracking, and disruption of the cell envelope with extracellular electron-dense materials. Increased permeability of the inner cell membrane caused cell death and lowered EPS production. Ag-NPs and ZnO-NPs also disrupted the surface adhering ability of bacteria, which varied with time and concentration of NPs. Conclusively, a plausible mechanism of NP toxicity to bacteria has been proposed to understand the mechanistic basis of ecological interaction between NPs and resourceful bacteria. These results also emphasize to develop strategies for the safe disposal of NPs.}, } @article {pmid32308750, year = {2020}, author = {Wang, C and Chen, P and Qiao, Y and Kang, Y and Yan, C and Yu, Z and Wang, J and He, X and Wu, H}, title = {pH responsive superporogen combined with PDT based on poly Ce6 ionic liquid grafted on SiO2 for combating MRSA biofilm infection.}, journal = {Theranostics}, volume = {10}, number = {11}, pages = {4795-4808}, pmid = {32308750}, issn = {1838-7640}, mesh = {Animals ; Biofilms/*drug effects ; Disease Models, Animal ; Hydrogen-Ion Concentration ; Ionic Liquids/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Photochemotherapy/*methods ; Photosensitizing Agents/chemistry ; Porosity ; Porphyrins/chemistry ; Rabbits ; Silicon Dioxide/*chemistry ; Staphylococcal Infections/*drug therapy/microbiology ; }, abstract = {Background: Biofilm infection caused by multidrug-resistant bacteria is difficult to eradicate by conventional therapies. Photodynamic therapy (PDT) is an effective antibacterial method for fighting against biofilm infection. However, the blocked photosensitizers outside of biofilm greatly limit the efficacy of PDT. Methods: Herein, a novel acid-responsive superporogen and photosensitizer (SiO2-PCe6-IL) was developed. Because of the protonation of the photosensitizer and the high binding energy of the polyionic liquid, SiO2-PCe6-IL changed to positive SiO2-PIL[+] in an acidic microenvironment of biofilm infection. SiO2-PIL[+] could combine with negatively charged extracellular polymeric substances (EPS) and create holes to remove the biofilm barrier. To strengthen the interaction between SiO2-PIL[+] and EPS, SiO2-PIL[+] of high charge density was prepared by grafting the high-density initiation site of ATRP onto the surface of the SiO2 base. Results: Due to the rapid protonation rate of COO[-] and the strong binding energy of SiO2-PIL[+] with EPS, SiO2-PCe6-IL could release 90% of Ce6 in 10 s. With the stronger electrostatic and hydrophobic interaction of SiO2-PIL[+] with EPS, the surface potential, hydrophobicity, adhesion and mechanical strength of biofilm were changed, and holes in the biofilm were created in 10 min. Combining with the release of photosensitizers and the porous structure of the biofilm, Ce6 was efficiently concentrated in the biofilm. The in vitro and in vivo antibacterial experiments proved that SiO2-PCe6-IL dramatically improved the PDT efficacy against MRSA biofilm infection. Conclusion: These findings suggest that SiO2-PCe6-IL could rapidly increase the concentration of photosensitizer in biofilm and it is an effective therapy for combating biofilm infection.}, } @article {pmid32307570, year = {2020}, author = {Shen, C and Islam, MT and Masuda, Y and Honjoh, KI and Miyamoto, T}, title = {Transcriptional changes involved in inhibition of biofilm formation by ε-polylysine in Salmonella Typhimurium.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {12}, pages = {5427-5436}, doi = {10.1007/s00253-020-10575-2}, pmid = {32307570}, issn = {1432-0614}, support = {DI-7201//Agriculture, Forestry and Fisheries Research Council/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Plastics ; Polylysine/*pharmacology ; Salmonella typhimurium/*drug effects/physiology ; }, abstract = {The pathogenicity of Salmonella Typhimurium, a foodborne pathogen, is mainly attributed to its ability to form biofilm on food contact surfaces. ε-polylysine, a polymer of positively charged lysine, is reported to inhibit biofilm formation of both gram-positive and gram-negative bacteria. To elucidate the mechanism underlying ε-polylysine-mediated inhibition of biofilm formation, the transcriptional profiles of ε-polylysine-treated and untreated Salmonella Typhimurium cells were comparatively analysed. The genome-wide DNA microarray analysis was performed using Salmonella Typhimurium incubated with 0.001% ε-polylysine in 0.1% Bacto Soytone at 30 °C for 2 h. The expression levels of genes involved in curli amyloid fibres and cellulose production, quorum sensing, and flagellar motility were downregulated, whereas those of genes associated with colanic acid synthesis were upregulated after treatment with ε-polylysine. The microarray results were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, treatment with ε-polylysine decreased the production of colanic acid in Salmonella Typhimurium. The findings of this study improved our understanding of the mechanisms underlying ε-polylysine-mediated biofilm inhibition and may contribute to the development of new disinfectants to control biofilm during food manufacturing and storage.}, } @article {pmid32307173, year = {2020}, author = {Elegbeleye, JA and Buys, EM}, title = {Molecular characterization and biofilm formation potential of Bacillus subtilis and Bacillus velezensis in extended shelf-life milk processing line.}, journal = {Journal of dairy science}, volume = {103}, number = {6}, pages = {4991-5002}, doi = {10.3168/jds.2019-17919}, pmid = {32307173}, issn = {1525-3198}, mesh = {Animals ; Bacillus/*growth & development/isolation & purification ; Bacillus subtilis/*growth & development ; *Biofilms ; *Dairying ; Milk/*microbiology ; Multilocus Sequence Typing ; Pasteurization ; Spores, Bacterial/isolation & purification ; }, abstract = {This study aims to characterize Bacillus subtilis complex group from raw, pasteurized, and packaged extended shelf-life (ESL) milk samples, to determine their biofilm potential and source-track the microbial contaminants to control their presence during processing. Isolates were characterized using multi-locus sequence typing (MLST) with 7 housekeeping genes. The primers used were designed from the coding regions with the highest number of polymorphic sites. The heat resistance profile indicated that all 12 isolates are psychrotolerant as well as thermophilic, with temperature ranges of 6°C to 55°C (B43, B44, B52, B54, B55, B56, B57), 6°C to 60°C (B46, B47, B48), and 15°C to 60°C (B49, B50). A general linear model 2-way repeated-measure ANOVA of the biofilm-forming potential of the isolates shows a statistically significant difference across the time of incubation (6, 12, 18, and 24 h). All isolates except 2 formed moderate to strong biofilms, with B44 having the most robust biofilm formation (3.14 ± 0.60). Scanning electron and confocal microscopy images reveal the strain specificity of the biofilm structure. The MLST analysis identified all isolates as belonging to either B. subtilis or Bacillus velezensis. All the isolates were novel sequence types (ST) when compared with the PubMLST database (https://pubmlst.org/) but showed relatedness to isolates in the raw milk that was processed. The closest ST are 96 for B. velezensis and 128 for B. subtilis, mostly isolated from soil. This study presents the significance of biofilms of thermophilic B. subtilis and B. velezensis and their possible perpetuation in the dairy processing plant. The information provided is a call for an innovative food contact surface or any other intervention that can minimize or prevent microbial adhesion in the processing plant, to prevent negative effects in ESL milk.}, } @article {pmid32304794, year = {2020}, author = {Alvarenga, DJ and Matias, LMF and Oliveira, LM and Leão, LPMO and Hawkes, JA and Raimundo, BVB and Castro, LFD and Campos, MMA and Siqueira, FDS and Santos, TD and Carvalho, DT}, title = {Exploring how structural changes to new Licarin A derivatives effects their bioactive properties against rapid growing mycobacteria and biofilm formation.}, journal = {Microbial pathogenesis}, volume = {144}, number = {}, pages = {104203}, doi = {10.1016/j.micpath.2020.104203}, pmid = {32304794}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Clarithromycin/pharmacology ; Lignans/*chemistry/*pharmacology ; Microbial Sensitivity Tests ; Mycobacterium/*drug effects ; Myristica/chemistry ; Nontuberculous Mycobacteria/*drug effects/physiology ; Sulfamethoxazole/pharmacology ; }, abstract = {Several species of rapidly growing mycobacteria (RGM) have been associated with biofilms in areas such as biomedical devices, water distribution systems, cosmetic surgery, and catheter-related blood infections. Biofilms which exhibit antimicrobial resistance such as those formed by the genus Mycobacterium pose a significant risk to health and are of particular interest to researchers. Licarin A (a neolignan found in numerous plant species e.g. nutmeg) has been reported to show a wide range of biological actions including anti-inflammatory, antioxidant, and antibacterial properties. The aim of this study was to prepare a set of Licarin A derivatives and investigate the impact of specific structural changes on its antimycobacterial ability, and its effect on the biofilm formation of RGM species. Initially, the phenolic sub-unit and alkenyl side chain of Licarin A were modified to create derivatives with a higher partition coefficient; as the activity of a compound against mycobacteria seems to be strongly influenced by its hydrophobicity. Further, polar groups were inserted into the side chain to change the hydrophilic-lipophilic profile of the molecules. Results showed variability in the susceptibility profile of mycobacteria against the Licarin A derivatives under analysis. A number of the derivatives showed significant inhibitory activity of planktonic growth of the three strains of mycobacteria used, with even lower MIC values than those observed with reference drugs and Licarin A itself. Cytotoxicity assays showed they also have low toxicity, confirming that structural modifications to the Licarin A have made improvements to its antimycobacterial properties.}, } @article {pmid32303851, year = {2020}, author = {Grudlewska-Buda, K and Skowron, K and Gospodarek-Komkowska, E}, title = {Comparison of the intensity of biofilm formation by Listeria monocytogenes using classical culture-based method and digital droplet PCR.}, journal = {AMB Express}, volume = {10}, number = {1}, pages = {75}, pmid = {32303851}, issn = {2191-0855}, abstract = {Listeria monocytogenes is a Gram-positive bacterium, commonly found in food, water or sewage. This microorganism is capable of forming biofilm on different surfaces such as steel, glass, polypropylene etc. Recently an increase in cases of listeriosis has been noted, making L. monocytogenes the important health threat. Therefore, there is a need for rapid and sensitive detection of this pathogen. This study aimed to compare the number of L. monocytogenes cells recovered from the biofilm (prepared on steel and polypropylene) using the detection and amplification of the hlyA gene (droplet digital PCR, ddPCR) and the classical culture method. The research material consisted of 96 L. monocytogenes strains. A total of 58 isolates were obtained from clinical samples and 38 isolates derived from the municipal sewage treatment plant. Additionally, the reference strain ATCC[®]19111™ (WDCM00020) was used. The Pearson correlation coefficient for the results obtained by the classical culture-based method and ddPCR was 0.864 and 0.725, for biofilms produced on AISI 304 stainless steel surface and the polypropylene surface, respectively. Correlations were statistically significant (p ≤ 0.001), indicating that the ddPCR technique is an effective tool for the assessment of bacteria number in the biofilm.}, } @article {pmid32302854, year = {2020}, author = {Peng, YY and Gao, F and Yang, HL and Wu, HW and Li, C and Lu, MM and Yang, ZY}, title = {Simultaneous removal of nutrient and sulfonamides from marine aquaculture wastewater by concentrated and attached cultivation of Chlorella vulgaris in an algal biofilm membrane photobioreactor (BF-MPBR).}, journal = {The Science of the total environment}, volume = {725}, number = {}, pages = {138524}, doi = {10.1016/j.scitotenv.2020.138524}, pmid = {32302854}, issn = {1879-1026}, mesh = {Aquaculture ; Biofilms ; Biomass ; *Chlorella vulgaris ; *Microalgae ; Nitrogen/analysis ; Nutrients ; Phosphorus ; Photobioreactors ; Sulfonamides ; Wastewater ; }, abstract = {Microalgae based wastewater treatment has attracted increasing attention for its many advantages in recent years. In this study, a novel microalgae biofilm membrane photobioreactor (BF-MPBR) was developed for the efficient microalgae cultivation and the removal of nutrient and sulfonamides (SAs) from marine aquaculture wastewater. Two BF-MPBRs with hydraulic retention time (HRT) of 1 day and 2 days respectively were continuously operated for 70 days without harvesting microalgae. Concentrated and attached culture of marine Chlorella vulgaris was achieved in these continuous flow BF-MPBRs due to the suspended solid carriers and microfiltration membrane module in the reactors. The algal biomass productivity achieved in BF-MPBRs with HRT of 1 day and 2 days were 14.02 and 22.03 mg L[-1] day[-1], respectively. In addition, at the end of the cultivation, 60.4% and 45.0% of microalgae were fixed into algal biofilm in BF-MPBRs with 1 day and 2 day HRT, respectively. Compared with batch cultivation, more efficient nutrient and SAs removal performance was achieved in BF-MPBRs, although the HRT of the BF-MPBRs used in this study was only 1 or 2 days. During the stable operation stage of the BF-MPBRs, the reduction in dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), sulfadiazine (SDZ), sulfamethazine (SMZ) and sulfamethoxazole (SMX) were found in the range of 91.0-99.6%, 92.1-98.4%, 61.0-79.2%, 50.0-76.7% and 60.8-82.1%, respectively. Therefore, nutrient and SAs were simultaneously and efficiently removed from marine aquaculture wastewater by microalgae cultivation in BF-MPBR.}, } @article {pmid32302361, year = {2020}, author = {Pestrak, MJ and Gupta, TT and Dusane, DH and Guzior, DV and Staats, A and Harro, J and Horswill, AR and Stoodley, P}, title = {Investigation of synovial fluid induced Staphylococcus aureus aggregate development and its impact on surface attachment and biofilm formation.}, journal = {PloS one}, volume = {15}, number = {4}, pages = {e0231791}, pmid = {32302361}, issn = {1932-6203}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion/drug effects/*physiology ; Biofilms/drug effects/*growth & development ; Fibrinogen/pharmacology ; Fibronectins/pharmacology ; Humans ; Staphylococcus aureus/drug effects/*physiology ; Synovial Fluid/drug effects/*microbiology ; Time Factors ; }, abstract = {Periprosthetic joint infections (PJIs) are a devastating complication that occurs in 2% of patients following joint replacement. These infections are costly and difficult to treat, often requiring multiple corrective surgeries and prolonged antimicrobial treatments. The Gram-positive bacterium Staphylococcus aureus is one of the most common causes of PJIs, and it is often resistant to a number of commonly used antimicrobials. This tolerance can be partially attributed to the ability of S. aureus to form biofilms. Biofilms associated with the surface of indwelling medical devices have been observed on components removed during chronic infection, however, the development and localization of biofilms during PJIs remains unclear. Prior studies have demonstrated that synovial fluid, in the joint cavity, promotes the development of bacterial aggregates with many biofilm-like properties, including antibiotic resistance. We anticipate these aggregates have an important role in biofilm formation and antibiotic tolerance during PJIs. Therefore, we sought to determine specifically how synovial fluid promotes aggregate formation and the impact of this process on surface attachment. Using flow cytometry and microscopy, we quantified the aggregation of various clinical S. aureus strains following exposure to purified synovial fluid components. We determined that fibrinogen and fibronectin promoted bacterial aggregation, while cell free DNA, serum albumin, and hyaluronic acid had minimal effect. To determine how synovial fluid mediated aggregation affects surface attachment, we utilized microscopy to measure bacterial attachment. Surprisingly, we found that synovial fluid significantly impeded bacterial surface attachment to a variety of materials. We conclude from this study that fibrinogen and fibronectin in synovial fluid have a crucial role in promoting bacterial aggregation and inhibiting surface adhesion during PJI. Collectively, we propose that synovial fluid may have conflicting protective roles for the host by preventing adhesion to surfaces, but by promoting bacterial aggregation is also contributing to the development of antibiotic tolerance.}, } @article {pmid32299665, year = {2020}, author = {Vyas, N and Grewal, M and Kuehne, SA and Sammons, RL and Walmsley, AD}, title = {High speed imaging of biofilm removal from a dental implant model using ultrasonic cavitation.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {6}, pages = {733-743}, doi = {10.1016/j.dental.2020.03.003}, pmid = {32299665}, issn = {1879-0097}, mesh = {Biofilms ; *Dental Implants ; Dental Scaling ; Microscopy, Electron, Scanning ; Surface Properties ; *Ultrasonics ; }, abstract = {OBJECTIVES: Current instruments cannot clean in between dental implant threads and effectively remove biofilm from the rough implant surface without damaging it. Cavitation bubbles have the potential to disrupt biofilms. The aim of this study was to see how biofilms can be disrupted using non-contact cavitation from an ultrasonic scaler, imaged inside a restricted implant pocket model using high speed imaging.

METHODS: Streptococcus sanguinis biofilm was grown for 7 days on dental implants. The implants were placed inside a custom made restricted pocket model and immersed inside a water tank. An ultrasonic scaler tip was placed 0.5mm away from the implant surface and operated at medium power or high power for 2s. The biofilm removal process was imaged using a high speed camera operating at 500 fps. Image analysis was used to calculate the amount of biofilm removed from the high speed images. Scanning electron microscopy was done to visualize the implant surface after cleaning.

RESULTS: Cavitation was able to remove biofilm from dental implants. More biofilm was removed at high power. Scanning electron microscopy showed that the implant surface was clean at the points where the cavitation was most intense. High speed imaging showed biofilm removal underneath implant threads, in areas next to the ultrasonic scaler tip.

SIGNIFICANCE: A high speed imaging protocol has been developed to visualize and quantify biofilm removal from dental implants in vitro. Cavitation bubbles from dental ultrasonic scalers are able to successfully disrupt biofilm in between implant threads.}, } @article {pmid32295873, year = {2020}, author = {Bailey, MT and Lauber, CL and Novotny, LA and Goodman, SD and Bakaletz, LO}, title = {Immunization with a Biofilm-Disrupting Nontypeable Haemophilus influenzae Vaccine Antigen Did Not Alter the Gut Microbiome in Chinchillas, Unlike Oral Delivery of a Broad-Spectrum Antibiotic Commonly Used for Otitis Media.}, journal = {mSphere}, volume = {5}, number = {2}, pages = {}, pmid = {32295873}, issn = {2379-5042}, support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {Administration, Oral ; Amoxicillin-Potassium Clavulanate Combination ; Animals ; Anti-Bacterial Agents ; Antibodies, Bacterial/blood ; Antigens, Bacterial/*administration & dosage/immunology ; Biofilms/*growth & development ; Chinchilla/microbiology ; Cohort Studies ; Ear, Middle/microbiology ; Female ; *Gastrointestinal Microbiome ; Haemophilus Infections/immunology/prevention & control ; Haemophilus Vaccines/*administration & dosage ; Haemophilus influenzae/immunology/pathogenicity ; Immunization ; Male ; Otitis Media/drug therapy/microbiology/*prevention & control ; }, abstract = {The use of broad-spectrum antibiotics to treat diseases, such as the highly prevalent pediatric disease otitis media (OM), contributes significantly to the worldwide emergence of multiple-antibiotic-resistant microbes, and gut dysbiosis with diarrhea is a common adverse sequela. Moreover, for many diseases, like OM, biofilms contribute significantly to chronicity and recurrence, yet biofilm-resident bacteria are characteristically highly resistant to antibiotics. The most cost-effective way to both prevent and resolve diseases like OM, as well as begin to address the problem of growing antibiotic resistance, would be via the development of novel approaches to eradicate bacterial biofilms. Toward this goal, we designed a vaccine antigen that induces the formation of antibodies that prevent biofilm formation and, thereby, experimental OM in the middle ears of chinchillas by the predominant Gram-negative pathogen responsible for this disease, nontypeable Haemophilus influenzae These antibodies also significantly disrupt preexisting biofilms formed by diverse pathogens. Whereas preclinical data strongly support the continued development of this vaccine antigen, which targets an essential structural element of bacterial biofilms, a concern has been whether active immunization would also lead to unintended collateral damage in the form of an altered gut microbiome. To address this concern, we assessed changes in the microbiome of the chinchilla gut over time after the delivery of either amoxicillin-clavulanate, the standard of care for OM, or after immunization with our biofilm-targeted vaccine antigen either via a traditional subcutaneous route or via a novel noninvasive transcutaneous route. We show that differences in the abundance of specific taxa were found only in the stools of antibiotic-treated animals.IMPORTANCE The prevalence of chronic and recurrent diseases, combined with the overuse/abuse of antibiotics that has led to the sobering emergence of bacteria resistant to multiple antibiotics, has mandated that we develop novel approaches to better manage these diseases or, ideally, prevent them. Biofilms play a key role in the pathogenesis of chronic and recurrent bacterial diseases but are difficult, if not impossible, to eradicate with antibiotics. We developed a vaccine antigen designed to mediate biofilm disruption; however, it is also important that delivery of this vaccine does not induce collateral damage to the microbiome. The studies described here validated a vaccine approach that targets biofilms without the consequences of an altered gut microbiome. While delivery of the antibiotic most commonly given to children with ear infections did indeed alter the gut microbiome, as expected, immunization via traditional injection or by noninvasive delivery to the skin did not result in changes to the chinchilla gut microbiome.}, } @article {pmid32294591, year = {2020}, author = {Li, T and Zhou, Q and Zhou, L and Yan, Y and Liao, C and Wan, L and An, J and Li, N and Wang, X}, title = {Acetate limitation selects Geobacter from mixed inoculum and reduces polysaccharide in electroactive biofilm.}, journal = {Water research}, volume = {177}, number = {}, pages = {115776}, doi = {10.1016/j.watres.2020.115776}, pmid = {32294591}, issn = {1879-2448}, mesh = {Acetates ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Geobacter ; Polysaccharides ; }, abstract = {Bioelectrochemical systems (BESs) are widely investigated as a promising technology to recover bioenergy or synthesize value-added products from wastewaters. The performance of BES depends on the activity of electroactive biofilm (EAB). As the core of BES, it is still unclear how the EAB is formed from mixed inoculum, and how exoelectrogens compete with non-exoelectrogens. Here we confirmed that microbial community composition and the morphology of EAB on the electrode including the thickness and porosity of the biofilm are critical for the performance of BES, and these properties can be simply controlled by the substrate concentration during EAB formation. The EAB formed with 0.1 g/L of acetate (EAB-0.1) exhibited a 90% higher current density than that formed with 1.0 g/L acetate (EAB-1.0). EAB-0.1 had a 50% higher electroactivity per biomass and a 20% thinner thickness than EAB-1.0, which was partly due to the 54% decrease of insulative polysaccharide in biofilm. Limited acetate also imposed a selective pressure to enrich Geobacter up to 88% compared to 72% when acetate was abundant. Our findings demonstrate that a highly active EAB can be formed by limiting substrate concentration, providing a broader understanding of the EAB formation process, the ecology of interspecies competitions and potential applications for bioenergy recovery and trace toxicant detection in the future.}, } @article {pmid32292058, year = {2020}, author = {Janek, T and Drzymała, K and Dobrowolski, A}, title = {In vitro efficacy of the lipopeptide biosurfactant surfactin-C15 and its complexes with divalent counterions to inhibit Candida albicans biofilm and hyphal formation.}, journal = {Biofouling}, volume = {36}, number = {2}, pages = {210-221}, doi = {10.1080/08927014.2020.1752370}, pmid = {32292058}, issn = {1029-2454}, mesh = {Antifungal Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development/metabolism ; Coordination Complexes/*pharmacology ; Fungal Proteins/genetics ; Green Fluorescent Proteins/genetics ; Hyphae/*drug effects/growth & development ; Lipopeptides/*pharmacology ; Peptides, Cyclic/*pharmacology ; Surface-Active Agents/*metabolism ; }, abstract = {Surfactin is a type of cyclic lipopeptide biosurfactant implicated in a wide range of applications. Although its antimicrobial activity has been characterized, its effect on Candida albicans physiology remains to be elucidated. The present study evaluated the influence of surfactin-C15 (SF) and its complexes with divalent counterions on C. albicans biofilm formation and preformed biofilms. The SF and metal(II)-SF complexes inhibited biofilm formation and reduced the metabolic activity of mature biofilms in a concentration-dependent manner. The same concentrations of the compounds studied dislodged preexisting biofilms grown on polystyrene plates. Moreover, SF and its metal(II) complexes reduced the mRNA expression of hypha-specific genes HWP1, ALS1, ALS3, ECE1 and SAP4 without exhibiting significant growth inhibition. Further research showed that the compounds tested reduced cellular surface hydrophobicity (CSH). These results suggest that SF and metal(II)-SF complexes could be used as anti-biofilm agents against C. albicans hypha-related infections in clinical practice.}, } @article {pmid32290861, year = {2020}, author = {Aldrich, AL and Heim, CE and Shi, W and Fallet, RW and Duan, B and Kielian, T}, title = {TLR2 and caspase-1 signaling are critical for bacterial containment but not clearance during craniotomy-associated biofilm infection.}, journal = {Journal of neuroinflammation}, volume = {17}, number = {1}, pages = {114}, pmid = {32290861}, issn = {1742-2094}, support = {R01 AR073225/AR/NIAMS NIH HHS/United States ; R01 NS107369/NS/NINDS NIH HHS/United States ; R01NS107369/NS/NINDS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Caspase 1/*deficiency ; Containment of Biohazards/*methods ; Craniotomy/*adverse effects ; Female ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Signal Transduction/physiology ; Staphylococcal Infections/etiology/metabolism ; Staphylococcus aureus/growth & development ; Surgical Wound Infection/etiology/*metabolism ; Toll-Like Receptor 2/*deficiency ; }, abstract = {BACKGROUND: A craniotomy is required to access the brain for tumor resection or epilepsy treatment, and despite precautionary measures, infectious complications occur at a frequency of 1-3%. Approximately half of craniotomy infections are caused by Staphylococcus aureus (S. aureus) that forms a biofilm on the bone flap, which is recalcitrant to antibiotics. Our prior work in a mouse model of S. aureus craniotomy infection revealed a critical role for myeloid differentiation factor 88 (MyD88) in bacterial containment and pro-inflammatory mediator production. Since numerous receptors utilize MyD88 as a signaling adaptor, the current study examined the importance of Toll-like receptor 2 (TLR2) and TLR9 based on their ability sense S. aureus ligands, namely lipoproteins and CpG DNA motifs, respectively. We also examined the role of caspase-1 based on its known association with TLR signaling to promote IL-1β release.

METHODS: A mouse model of craniotomy-associated biofilm infection was used to investigate the role of TLR2, TLR9, and caspase-1 in disease progression. Wild type (WT), TLR2 knockout (KO), TLR9 KO, and caspase-1 KO mice were examined at various intervals post-infection to quantify bacterial burden, leukocyte recruitment, and inflammatory mediator production in the galea, brain, and bone flap. In addition, the role of TLR2-dependent signaling during microglial/macrophage crosstalk with myeloid-derived suppressor cells (MDSCs) was examined.

RESULTS: TLR2, but not TLR9, was important for preventing S. aureus outgrowth during craniotomy infection, as revealed by the elevated bacterial burden in the brain, galea, and bone flap of TLR2 KO mice concomitant with global reductions in pro-inflammatory mediator production compared to WT animals. Co-culture of MDSCs with microglia or macrophages, to model interactions in the brain vs. galea, respectively, also revealed a critical role for TLR2 in triggering pro-inflammatory mediator production. Similar to TLR2, caspase-1 KO animals also displayed increased S. aureus titers coincident with reduced pro-inflammatory mediator release, suggestive of pathway cooperativity. Treatment of caspase-1 KO mice with IL-1β microparticles significantly reduced S. aureus burden in the brain and galea compared to empty microparticles, confirming the critical role of IL-1β in limiting S. aureus outgrowth during craniotomy infection.

CONCLUSIONS: These results demonstrate the existence of an initial anti-bacterial response that depends on both TLR2 and caspase-1 in controlling S. aureus growth; however, neither pathway is effective at clearing infection in the WT setting, since craniotomy infection persists when both molecules are present.}, } @article {pmid32290491, year = {2020}, author = {Przekwas, J and Wiktorczyk, N and Budzyńska, A and Wałecka-Zacharska, E and Gospodarek-Komkowska, E}, title = {Ascorbic Acid Changes Growth of Food-Borne Pathogens in the Early Stage of Biofilm Formation.}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32290491}, issn = {2076-2607}, support = {UPB 523//Uniwersytet Mikolaja Kopernika w Toruniu/ ; }, abstract = {Since bacterial biofilm may contribute to the secondary contamination of food during the manufacturing/processing stage there is a need for new methods allowing its effective eradication. Application of food additives such as vitamin C already used in food industry as antioxidant food industry antioxidants may be a promising solution. The aim of this research was evaluation of the impact of vitamin C (ascorbic acid), in a range of concentrations 2.50 µg mL[-1]-25.0 mg mL[-1], on biofilms of Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes strains isolated from food. The efficacy of ascorbic acid was assessed based on the reduction of optical density (λ = 595 nm). The greatest elimination of the biofilm was achieved at the concentration of vitamin C of 25.0 mg mL[-1]. The effect of the vitamin C on biofilm, however, was strain dependent. The concentration of 25.0 mg mL[-1] reduced 93.4%, 74.9%, and 40.5% of E. coli, L. monocytogenes, and S. aureus number, respectively. For E. coli and S. aureus lower concentrations were ineffective. In turn, for L. monocytogenes the biofilm inhibition was observed even at the concentration of 0.25 mg mL[-1]. The addition of vitamin C may be helpful in the elimination of bacterial biofilms. Nonetheless, some concentrations can induce growth of the pathogens, posing risk for the consumers' health.}, } @article {pmid32289462, year = {2020}, author = {Anane, YA and Apalata, T and Vasaikar, S and Okuthe, GE and Songca, SP}, title = {In vitro antimicrobial photodynamic inactivation of multidrug-resistant Acinetobacter baumannii biofilm using Protoporphyrin IX and Methylene blue.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {30}, number = {}, pages = {101752}, doi = {10.1016/j.pdpdt.2020.101752}, pmid = {32289462}, issn = {1873-1597}, mesh = {*Acinetobacter Infections/drug therapy ; *Acinetobacter baumannii ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Humans ; Methylene Blue/pharmacology/therapeutic use ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology/therapeutic use ; Protoporphyrins ; }, abstract = {BACKGROUND: Acinetobacter baumannii is a challenging pathogen due to the rapid development of antimicrobial resistance and biofilm formation. The objective of this study was to evaluate the effect of antimicrobial photodynamic inactivation against biofilms of multidrug-resistant A. baumannii isolated from clinical, abattoir and aquatic sources.

METHODS: The isolates were tested for susceptibility to imipenem, meropenem, tigecycline and colistin using autoSCAN-4 automated system and rechecked by the E-test. Methylene blue, Protoporphyrin IX, and a halogen lamp were used in the in vitro assay against biofilms of the isolates. The antimicrobial photodynamic inactivation was assessed by counting colony-forming units (CFU).

RESULTS: The isolates from abattoir and aquatic sources were resistant to carbapenems (>64 μg/mL) but susceptible to tigecycline (2 μg/mL) and colistin (Abattoir, 0.35 μg/mL and Aquatic, 0.24 μg/mL), whereas the clinical isolate was susceptible to only colistin (0.5 μg/mL) using the E-test. The log survival percentages of the control group at a concentration of 20 μM were 5 × 10[-6] % for Protoporphyrin IX and 2 × 10[-6] % for Methylene blue. Therefore, Methylene blue showed higher bacterial reduction of 7.0 log10 colony forming units than 6.0 log10 for Protoporphyrin IX. No significant difference was observed with respect to the origin of isolates and the minimum inhibitory concentrations.

CONCLUSION: The results indicate that antimicrobial photodynamic inactivation could be an alternative strategy for the control of infections caused by multi-drug resistant A. baumannii by significantly reducing biofilm growth at a sub-lethal concentrations.}, } @article {pmid32289218, year = {2020}, author = {Amin, M and Rowley-Neale, S and Shalamanova, L and Lynch, S and Wilson-Nieuwenhuis, JT and El Mohtadi, M and Banks, CE and Whitehead, KA}, title = {Molybdenum Disulfide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {18}, pages = {21057-21069}, doi = {10.1021/acsami.0c02278}, pmid = {32289218}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology/toxicity ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Cell Line ; Disulfides/chemistry/*pharmacology/toxicity ; Humans ; Molybdenum/chemistry/*pharmacology/toxicity ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; Wettability ; }, abstract = {The reduction of bacteria and biofilm formation is important when designing surfaces for use in industry. Molybdenum disulfide surfaces (MoS2SUR) were produced using MoS2 particle (MoS2PAR) sizes of 90 nm, 2 μm, and 6 μm containing MoS2PAR concentrations of 5%, 10%, 15%, and 20%. These were tested to determine the efficacy of the MoS2SUR to impede bacterial retention and biofilm formation of two different types of bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. The MoS2SUR were characterized using Fourier transform infrared spectroscopy, ion-coupled plasma atomic emission spectroscopy, scanning electron microscopy, optical profilometry, and water contact angles. The MoS2SUR made with the smaller 90 nm MoS2PAR sizes demonstrated smaller topographical-shaped features. As the size of the incorporated MoS2PAR increased, the MoS2SUR demonstrated wider surface features, and they were less wettable. The increase in MoS2PAR concentration within the MoS2SUR groups did not affect the surface topography but did increase wettability. However, the increase in MoS2PAR size increased both the surface topography and wettability. The MoS2SUR with the smaller topographical-shaped features influenced the retention of the S. aureus bacteria. Increased MoS2SUR topography and wettability resulted in the greatest reduction in bacterial retention, and the bacteria became more heterogeneously dispersed and less clustered across the surfaces. The surfaces that exhibited decreased bacterial retention (largest particle sizes, largest features, greatest roughness, and most wettable) resulted in decreased biofilm formation. Cytotoxicity testing of the surface using cell viability demonstrated that the MoS2SUR were not toxic against HK-2 cells at MoS2PAR sizes of 90 nm and 2 μm. This work demonstrated that individual surface variables (MoS2SUR topographic shape and roughness, MoS2PAR size, and concentration) decreased bacterial loading on the surfaces, which then decreased biofilm formation. By optimizing MoS2SUR properties, it was possible to impede bacterial retention and subsequent biofilm formation.}, } @article {pmid32285904, year = {2020}, author = {Bhatia, E and Banerjee, R}, title = {Hybrid silver-gold nanoparticles suppress drug resistant polymicrobial biofilm formation and intracellular infection.}, journal = {Journal of materials chemistry. B}, volume = {8}, number = {22}, pages = {4890-4898}, doi = {10.1039/d0tb00158a}, pmid = {32285904}, issn = {2050-7518}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Infections/*drug therapy ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/drug effects ; Cells, Cultured ; Drug Resistance, Bacterial/drug effects ; Gold/chemistry/*pharmacology ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Humans ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Particle Size ; Quercetin/chemistry ; Silver/chemistry/*pharmacology ; Surface Properties ; }, abstract = {Over decades bacteria have evolved multiple mechanisms to fight antibiotics. Biofilm formation by bacteria is one such mechanism as it forms a barrier and creates an acidic environment that reduces the efficiency of antimicrobials. Bacteria have also developed the ability to persist intracellularly within mammalian cells, causing recurrent infections. Many antibiotics are rendered ineffective due to poor penetration across biofilms and within mammalian cells. In this study, silver-gold hybrid nanoparticles were developed as anti-microbial agents to combat biofilm formation and intracellular infections. Biogenic hybrid silver gold nanoparticles were developed in an organic solvent free single reaction mixture using quercetin, a flavonoid, as the reducing and stabilizing agent. Silver-gold nanoparticles of 40 ± 10 nm diameter were effective against a broad spectrum of bacteria with minimum bactericidal concentrations of 10 μg ml-1 and 20 μg ml-1 for Gram negative and Gram-positive organisms, respectively. These nanoparticles were also effective against mixed infections at 20 μg ml-1. Their mode of action involves generating intracellular oxidative stress in both Gram negative and Gram-positive bacteria, which causes damage to the cell wall. Polymicrobial biofilm formation was suppressed and intracellular infection was reduced by 70% to 90% in fibroblast and monocyte cell lines. These results indicate that hybrid silver gold nanoparticles are promising agents to suppress biofilm formation and tackle intracellular infections.}, } @article {pmid32284373, year = {2020}, author = {Chen, HH and Chang, CC and Yuan, YH and Liaw, SJ}, title = {A CpxR-Regulated zapD Gene Involved in Biofilm Formation of Uropathogenic Proteus mirabilis.}, journal = {Infection and immunity}, volume = {88}, number = {7}, pages = {}, pmid = {32284373}, issn = {1098-5522}, mesh = {Bacterial Proteins/*genetics ; *Biofilms ; Cell Cycle Proteins/*genetics ; Copper/metabolism ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Mutation ; Promoter Regions, Genetic ; Proteus Infections/*microbiology ; Proteus mirabilis/*physiology ; Sequence Analysis, DNA ; }, abstract = {Proteus mirabilis, a frequent uropathogen, forms extensive biofilms on catheters that are infamously difficult to treat. To explore the mechanisms of biofilm formation by P. mirabilis, we performed in vivo transposon mutagenesis. A mutant with impaired biofilm formation was isolated. The mutant was found to have Tn5 inserted in the zapD gene, encoding an outer membrane protein of the putative type 1 secretion system ZapBCD. zapBCD and its upstream zapA gene, encoding a protease, constitute an operon under the control of CpxR, a two-component regulator. The cpxR mutant and zapA mutant strains also had a biofilm-forming defect. CpxR positively regulates the promoter activities of zapABCD, cpxP, and cpxR An electrophoretic mobility shift assay revealed that CpxR binds zapA promoter DNA. The loss of zapD reduced CpxR-regulated gene expression of cpxR, zapA, cpxP, and mrpA, the mannose-resistant Proteus-like (MR/P) fimbrial major subunit gene. The restoration of biofilm formation in the zapD mutant with a CpxR-expressing plasmid reinforces the idea that CpxR-mediated gene expression contributes to zapD-involved biofilm formation. In trans expression of zapBCD from a zapBCD-expressing plasmid also reestablished the biofilm formation ability of the cpxR mutant to a certain level. The zapD and cpxR mutants had significantly lower protease activity, adhesion, and autoaggregation ability and production of exopolysaccharides and extracellular DNA (eDNA) than did the wild type. Finally, we identified copper as a signal for CpxR to increase biofilm formation. The loss of cpxR or zapD abolished the copper-mediated biofilm upshift. CpxR was required for copper-induced expression of zapA and cpxR Taken together, these data highlight the important role of CpxR-regulated zapD in biofilm formation and the underlying mechanisms in P. mirabilis.}, } @article {pmid32283494, year = {2020}, author = {Vyas, N and Wang, QX and Manmi, KA and Sammons, RL and Kuehne, SA and Walmsley, AD}, title = {How does ultrasonic cavitation remove dental bacterial biofilm?.}, journal = {Ultrasonics sonochemistry}, volume = {67}, number = {}, pages = {105112}, doi = {10.1016/j.ultsonch.2020.105112}, pmid = {32283494}, issn = {1873-2828}, mesh = {Bacteria/*isolation & purification ; *Biofilms ; Microbubbles ; *Sonication ; Streptococcus/growth & development ; Surface Properties ; Tooth/*microbiology ; }, abstract = {Bacterial biofilm accumulation is problematic in many areas, leading to biofouling in the marine environment and the food industry, and infections in healthcare. Physical disruption of biofilms has become an important area of research. In dentistry, biofilm removal is essential to maintain health. The aim of this study is to observe biofilm disruption due to cavitation generated by a dental ultrasonic scaler (P5XS, Acteon) using a high speed camera and determine how this is achieved. Streptococcus sanguinis biofilm was grown on Thermanox™ coverslips (Nunc, USA) for 4 days. After fixing and staining with crystal violet, biofilm removal was imaged using a high speed camera (AX200, Photron). An ultrasonic scaler tip (tip 10P) was held 2 mm away from the biofilm and operated for 2 s. Bubble oscillations were observed from high speed image sequences and image analysis was used to track bubble motion and calculate changes in bubble radius and velocity on the surface. The results demonstrate that most of the biofilm disruption occurs through cavitation bubbles contacting the surface within 2 s, whether individually or in cavitation clouds. Cleaning occurs through shape oscillating microbubbles on the surface as well as through fluid flow.}, } @article {pmid32283260, year = {2020}, author = {Xi, D and Yang, S and Liu, Q and Li, Y and Li, Y and Yan, J and Wang, X and Ning, K and Cao, B}, title = {The response regulator ArcA enhances biofilm formation in the vpsT manner under the anaerobic condition in Vibrio cholerae.}, journal = {Microbial pathogenesis}, volume = {144}, number = {}, pages = {104197}, doi = {10.1016/j.micpath.2020.104197}, pmid = {32283260}, issn = {1096-1208}, mesh = {*Anaerobiosis ; Bacterial Outer Membrane Proteins/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cholera/microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Oxygen/pharmacology ; Promoter Regions, Genetic ; Repressor Proteins/*genetics ; Vibrio cholerae/*genetics/*metabolism ; Virulence/genetics ; Virulence Factors/*genetics/metabolism ; }, abstract = {Vibrio cholerae, the agent of severe diarrheal disease cholera, is known to form biofilm to persist in the environmental and the host[,]s intestines. The bacteria execute a complex regulatory pathway producing virulence factors that allow colonization and cause disease in response to environmental signals in the intestine, including low oxygen-limited condition. VpsR and VpsT are primary regulators of the biofilm formation-regulatory network. In this study, we determined that anaerobic induction enhanced biofilm formation via the two component system, ArcB/A, which functions as a positive regulator of toxT expression. The biofilm formation has reduced approximately 2.4-fold in the ΔarcA mutant compared to the wild type in anaerobic condition. Chip-qPCR and EMSA assays confirmed that ArcA can bind directly to the vpsT promoter and then activates the expression of biofilm formation related genes, vpsA-K and vpsL-Q. Meanwhile, the ΔarcA mutant decreased the ability of colonization in intestine with CI (competition index) of 0.27 compared to wild type strain. These results suggest that ArcA links the expression of virulence and biofilm synthesis genes during anaerobic condition, and contributes to understand the complex relationship between biofilm formation and the intestinal signals during infection.}, } @article {pmid32283258, year = {2020}, author = {Zhao, F and Yang, H and Bi, D and Khaledi, A and Qiao, M}, title = {A systematic review and meta-analysis of antibiotic resistance patterns, and the correlation between biofilm formation with virulence factors in uropathogenic E. coli isolated from urinary tract infections.}, journal = {Microbial pathogenesis}, volume = {144}, number = {}, pages = {104196}, doi = {10.1016/j.micpath.2020.104196}, pmid = {32283258}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Databases, Factual ; Drug Resistance, Bacterial/*drug effects/genetics ; Escherichia coli Infections/epidemiology ; Humans ; Iran/epidemiology ; Microbial Sensitivity Tests ; Urinary Tract Infections/drug therapy/*microbiology ; Uropathogenic Escherichia coli/*drug effects/genetics/*isolation & purification ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {Urinary tract infection (UTI) is caused by the invasion of the pathogen in the urinary system that can manifest as symptomatic or asymptomatic bacteriuria. This study was conducted to investigate antibiotic resistance patterns, and the correlation between biofilm formations with virulence factors in uropathogenic E. coli isolates retrieved from UTI. We searched Scopus and Google Scholar, PubMed, Web of sciences for studies published in the English language between 1st 2005 to 31st December 2019. The Mesh terms and text words included "biofilms", OR "biofilm formation", AND "antibiotic resistance", OR "drug-resistance", OR "antimicrobial drug resistance", AND "urinary tract infections", OR "UTI", AND "biofilm related-genes", AND "virulence factors" AND "correlation", AND "Uropathogenic Escherichia coli", OR "Uropathogenic E. coli" AND "prevalence" AND "Iran". Data analyzed using Comprehensive Meta-Analysis (CMA) software. The random-effects model was used to calculate the pooled prevalence with 95% confidence interval (CI). The combined rates of biofilm formation in Uropathogenic E. coli (UPEC) isolates were achieved as 84.6% (95% CI: 72.7-91.9). Also, 24.8%, 26.1% and 44.6% of UPEC isolates were able to create strong, moderate and weak biofilm, respectively. The highest pooled antibiotic resistance was against Ampicillin followed by Tetracycline with resistance rates of 74.6% and 64.9%, respectively. Accordingly, some studies reported that biofilm production was significantly associated with antibiotic resistance and virulence genes (p < 0.05). This study showed a high tendency among UPEC isolates to form biofilm (more than 84%), also, most studies included in the present review reported a significant correlation between biofilm formation with antibiotic resistance and virulence factors.}, } @article {pmid32281883, year = {2020}, author = {Talluri, SNL and Winter, RM and Salem, DR}, title = {Conditioning film formation and its influence on the initial adhesion and biofilm formation by a cyanobacterium on photobioreactor materials.}, journal = {Biofouling}, volume = {36}, number = {2}, pages = {183-199}, doi = {10.1080/08927014.2020.1748186}, pmid = {32281883}, issn = {1029-2454}, mesh = {Adsorption ; Anabaena/*growth & development/physiology ; *Bacterial Adhesion ; Biofilms/*growth & development ; Construction Materials/*microbiology ; Hydrophobic and Hydrophilic Interactions ; Photobioreactors/*microbiology ; Surface Properties ; }, abstract = {Although cyanobacteria are a common group of microorganisms well-suited to utilization in photobioreactors (PBRs), studies of cyanobacteria fouling and its prevention are scarce. Using a cyanobacterium, Anabaena sp. PCC 7120, which had been genetically modified to enhance linalool production, the formation of conditioning films and the effects of these on the physico-chemical surface properties of various PBR materials during initial adhesion and biofilm formation were investigated. The adhesion assay revealed that the overall attachment of Anabaena was substratum dependent and no correlation between the hydrophobicity/roughness of clean material and cell attachment was found. Surface hydrophilicity/hydrophobicity of all the materials changed within 12 h due to formation of conditioning films. ATR-FTIR spectroscopy revealed that the fractional change in protein deposition between 12 to 96 h was consistent with Anabaena cell attachment but polysaccharide deposition was material specific and did not correlate with cell attachment on the PBR materials. Also, the delay in conditioning film proteins on PVC and PTFE indicated that components other than proteins may be responsible for the decrease in contact angles on these surfaces within 12 h. This indicates the important role of the chemical nature of adsorbed conditioning films in determining the initial attachment of Anabaena to PBR materials. The lower rate of attachment of Anabaena on the hydrophilic surfaces (glass and PMMA) between 72 h to 96 h (regime 3) showed that these surfaces could potentially have low fouling characteristics at extended time scales and should be considered for further research.}, } @article {pmid32280870, year = {2020}, author = {Fallah Atanaki, F and Behrouzi, S and Ariaeenejad, S and Boroomand, A and Kavousi, K}, title = {BIPEP: Sequence-based Prediction of Biofilm Inhibitory Peptides Using a Combination of NMR and Physicochemical Descriptors.}, journal = {ACS omega}, volume = {5}, number = {13}, pages = {7290-7297}, pmid = {32280870}, issn = {2470-1343}, abstract = {Biofilms are biological systems that are formed by a community of microorganisms in which microbial cells are connected on a surface within a self-produced matrix of an extracellular polymeric substance. On some occasions, microorganisms use biofilms to protect themselves against the harmful effects of the host body immune system and the surrounding environment, hence increasing their chances of survival against the various anti-microbial agents. Biofilms play a crucial role in medicine and industry because of the problems they cause. Designing agents that inhibit bacterial biofilm formation is very costly and takes too much time in the laboratory to be discovered and validated. Therefore, developing computational tools for the prediction of biofilm inhibitor peptides is inevitable and important. Here, we present a computational prediction tool to screen the vast number of peptide sequences and select potential candidate peptides for further lab experiments and validation. In this learning model, different feature vectors, extracted from the peptide primary structure, are exploited to learn patterns from the sequence of biofilm inhibitory peptides. Various classification algorithms including SVM, random forest, and k-nearest neighbor have been examined to evaluate their performance. Overall, our approach showed better prediction in comparison with other prediction methods. In this study, for the first time, we applied features extracted from NMR spectra of amino acids along with physicochemical features. Although each group of features showed good discrimination potential alone, we used a combination of features to enhance the performance of our method. Our prediction tool is freely available.}, } @article {pmid32279616, year = {2020}, author = {Aramwit, P and Napavichayanum, S and Pienpinijtham, P and Rasmi, Y and Bang, N}, title = {Antibiofilm activity and cytotoxicity of silk sericin against Streptococcus mutans bacteria in biofilm: an in vitro study.}, journal = {Journal of wound care}, volume = {29}, number = {Sup4}, pages = {S25-S35}, doi = {10.12968/jowc.2020.29.Sup4.S25}, pmid = {32279616}, issn = {0969-0700}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Bombyx ; Humans ; Microbial Sensitivity Tests ; Pressure Ulcer/*microbiology ; Sericins/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {OBJECTIVE: To investigate the potential of sericin extracted by different methods to inhibit biofilm formation (prevention) and disrupt already formed biofilm (treatment).

METHOD: In this in vitro study, sericin was extracted by heat, acid, alkali and urea. Streptococcus mutans bacteria were cultivated in the presence of various concentrations of sericin to evaluate antibiofilm formation using cell density assay (inhibition effect before biofilm formed). Conversely, various concentrations of sericin were added to a biofilm already formed by Streptococcus mutans bacteria, and the viability of bacteria assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (disruption effects after biofilm formed). Structures of extracted sericin were evaluated using circular dichroism and Fourier-transform infrared spectrometer.

RESULTS: The urea-extracted sericin at all concentrations (12.5mg/ml, 25mg/ml, 50mg/ml and 100mg/ml) showed the highest potential antibiofilm activity in terms of both inhibition and disruption effects, compared with sericin extracted by heat, acid or alkali. The heat-extracted and acid-extracted sericin were found to reduce the biofilm formation dose-dependently, while the alkali-extracted sericin did not show either inhibition or disruption effect on the bacterial biofilm. The urea-extracted sericin also killed the bacteria residing within the biofilm, possibly due to its modified structure which may destabilise the bacterial cell wall, leading to membrane disintegration and, finally, cell death.

CONCLUSION: Our results demostrated the antibiofilm activity of sericin. This could form the basis of further research on the mechanism and application of sericin as a novel antibiofilm agent.}, } @article {pmid32279402, year = {2020}, author = {Di Marco, NI and Pungitore, CR and Lucero-Estrada, CSM}, title = {Aporphinoid alkaloids inhibit biofilm formation of Yersinia enterocolitica isolated from sausages.}, journal = {Journal of applied microbiology}, volume = {129}, number = {4}, pages = {1029-1042}, doi = {10.1111/jam.14664}, pmid = {32279402}, issn = {1365-2672}, support = {PROICO 02-1518//Science and Technology Department, National University of San Luis, Argentina/ ; PROICO 02-2516//Science and Technology Department, National University of San Luis, Argentina/ ; PROICO 2-0914//Science and Technology Department, National University of San Luis, Argentina/ ; //Alexander von Humboldt Foundation/ ; PICT-2015-1722//National Agency for Scientific and Technological Promotion, Argentina/ ; PICT-2017-0785//National Agency for Scientific and Technological Promotion, Argentina/ ; //CONICET/ ; //National University of San Luis/ ; }, mesh = {Alkaloids/chemistry/*pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Gene Expression Regulation, Bacterial/drug effects ; Meat Products/*microbiology ; Microbial Sensitivity Tests ; Quorum Sensing/drug effects ; Virulence Factors/genetics ; Yersinia enterocolitica/*drug effects/isolation & purification/physiology ; }, abstract = {AIMS OF THE STUDY: The ability of Yersinia enterocolitica strains to form biofilms and the capacity of different alkaloids to inhibit biofilm formation were investigated.

METHODS AND RESULTS: The capacity to form biofilm on polystyrene of 31 Y. enterocolitica strains was evaluated. Biofilm and quorum sensing (QS) inhibition of 17 alkaloids were assayed; furthermore, minimum biofilm inhibitory concentration (MBIC) was determined. The capacity to form biofilms among the examined strains seemed to be a strain-related feature. The best biofilm inhibitors at 100 µmol l[-1] were oliverine (1), guatterine (3), liriodenine (4), oliveridine (5) and pachypodanthine (6), which showed biofilm inhibition higher than 87%. Pachypodanthine (6) was the most effective compound with MBIC value of 12·5 µmol l[-1] at subinhibitory concentration and also was able to inhibit QS system and reduce yenR expression at this concentration.

CONCLUSION: This is the first study to demonstrate that oliverine, liriodenine, and pachypodanthine are able to inhibit biofilm formation of Y. enterocolitica without critically disturbing its growing capacity. At MBIC, pachypodanthine inhibited biofilm formation and QS.

The use of aporphinoid alkaloids as biofilms inhibitory agents might potentially be useful to treat biofilm-associated infections in the future.}, } @article {pmid32279229, year = {2021}, author = {Kumbar, VM and Peram, MR and Kugaji, MS and Shah, T and Patil, SP and Muddapur, UM and Bhat, KG}, title = {Effect of curcumin on growth, biofilm formation and virulence factor gene expression of Porphyromonas gingivalis.}, journal = {Odontology}, volume = {109}, number = {1}, pages = {18-28}, pmid = {32279229}, issn = {1618-1255}, mesh = {Adhesins, Bacterial/genetics ; Biofilms ; *Curcumin/pharmacology ; Gene Expression ; *Porphyromonas gingivalis ; Virulence Factors/genetics ; }, abstract = {Porphyromonas gingivalis is a keystone pathogen and major colonizer in host tissue which plays a pivotal role in periodontitis among the other polymicrobial infections. Increasing facts demonstrate that curcumin has antibacterial activity and anti-biofilm effect against the periodontopathogens through diverse mechanisms that have a positive impact on periodontal health. The present study was aimed to elucidate the effect of curcumin on biofilm formation and virulence factor gene expression of P. gingivalis. By using gene expression studies, we exploited the mechanism of anti-biofilm effects of curcumin on P. gingivalis. The minimum inhibitory concentration and minimum bactericidal concentration of curcumin for both ATCC and clinical strains of P. gingivalis were found to be 62.5 and 125 µg ml[-1] respectively. Curcumin prevented bacterial adhesion and biofilm formation in a dose-dependent manner. Further, curcumin attenuated the virulence of P. gingivalis by reducing the expression of genes coding for major virulence factors, including adhesions (fimA, hagA, and hagB) and proteinases (rgpA, rgpB, and kgp). The results indicated that curcumin has shown anti-biofilm as well as antibacterial activity against P. gingivalis. Further, curcumin because of its pleiotropic actions could be a simple and inexpensive therapeutic strategy in the treatment of periodontal disease.}, } @article {pmid32278760, year = {2020}, author = {Zhang, Z and Lyu, X and Xu, Q and Li, C and Lu, M and Gong, T and Tang, B and Wang, L and Zeng, W and Li, Y}, title = {Utilization of the extract of Cedrus deodara (Roxb. ex D.Don) G. Don against the biofilm formation and the expression of virulence genes of cariogenic bacterium Streptococcus mutans.}, journal = {Journal of ethnopharmacology}, volume = {257}, number = {}, pages = {112856}, doi = {10.1016/j.jep.2020.112856}, pmid = {32278760}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology/toxicity ; Biofilms/*drug effects/growth & development ; *Cedrus/chemistry/toxicity ; Cells, Cultured ; Dental Caries/microbiology/*prevention & control ; Gene Expression Regulation, Bacterial ; Glucosyltransferases/genetics ; Humans ; Plant Extracts/isolation & purification/*pharmacology/toxicity ; Streptococcus mutans/*drug effects/genetics/growth & development/pathogenicity ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {Cedrus deodara (Roxb. ex D.Don) G. Don is applied as anti-inflammatory and anti-infection agents in folklore medicine.

AIM OF THE STUDY: The present study aimed to assess the antimicrobial activity of Cedrus deodara (Roxb. ex D.Don) G. Don extract (CDE) against Streptococcus mutans biofilm formation and its biocompatibility, as well as to identify its chemical components.

MATERIALS AND METHODS: Confocal laser scanning microscopy (CLSM), crystal violet staining, and CFU counting assay were applied to investigate the effect of CDE on S. mutans biofilm formation and extracellular polysaccharides (EPS) synthesis. The microstructure of S. mutans biofilms formed on glass coverslips and bovine enamel treated with CDE was observed by scanning electron microscopy (SEM). qRT-PCR was used to measure the expression of virulence genes gtfB, gtfC, and gtfD, and zymogram assay was performed to investigate the enzymatic activity of Gtfs. Moreover, HPLC-MS and NMR were applied to identify its chemical components. CCK-8 assay was also performed on human oral cells to evaluate its biocompatibility.

RESULTS: Under the treatment of CDE, S. mutans formed less biofilm on both coverslips and enamel surfaces and synthesized less EPS. Moreover, CDE downregulated the expression of gtf genes and inhibited the enzymatic activity of Gtfs. According to HPLC-MS and NMR results, molecular structures of six main compounds in CDE were identified. CDE also has a good biocompatibility.

CONCLUSIONS: CDE exhibits inhibitory activity against S. mutans and a good biocompatibility. It has the potential to be developed as anti-caries agents for clinical use.}, } @article {pmid32278165, year = {2020}, author = {Wang, J and Zhou, J and Wang, Y and Wen, Y and He, L and He, Q}, title = {Efficient nitrogen removal in a modified sequencing batch biofilm reactor treating hypersaline mustard tuber wastewater: The potential multiple pathways and key microorganisms.}, journal = {Water research}, volume = {177}, number = {}, pages = {115734}, doi = {10.1016/j.watres.2020.115734}, pmid = {32278165}, issn = {1879-2448}, mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; Mustard Plant ; Nitrification ; *Nitrogen ; *Wastewater ; }, abstract = {This study first compared the efficiencies and mechanisms of the nitrogen removal in an aerobic sequencing batch biofilm reactor (SBBR) treating mustard tuber wastewater from high salt (30 gNaCl L[-1]) to ultra-high salt (70 gNaCl L[-1]). High-efficiency maintaining of nitrification was observed. Despite of high BOD5/TN (5.5-9), distinct denitrification decline for lack of carbon in response to salt stress was observed. Considering the high concentrations of sulfate in mustard wastewater, and the existence of sulfur-reducing bacteria (SRB) and sulfur-driven denitrifiers (DNSOB) in the aerobic SBBR, sulfate reduction-sulfur autotrophic denitrification process is a feasible idea to solve this problem. By modified to intermittent aeration mode, sulfur cycle was developed in SBBR. The average removal efficiency of COD, TN reached 85.20% and 98.56%, respectively. By batch activity tests and microbial community analysis, ammonia oxidation activity by ammonia-oxidizing archaea (AOA) was observed, and high abundance of AOA (Arch-amoA/AOB amoA: 2.38 × 10[2]) together with ammonia-oxidizing bacteria (AOB) of Nitrosomonas_halophila (1.23%) ensured the high efficient nitrification. After running mode change, specific sulfur-driven NO3[-]-N reduction rate increased and the abundance of dominant SRB and DNSOB rose from 3.95% to 10.79% and 2.22% to 9.95%, respectively. The sulfate-reducing process during anaerobic phase provided electron donors for subsequent autotrophic denitrification, making outlet NO3[-]-N concentrations reduced from 18.26 mg L[-1] to 1.93 mg L[-1]. The sulfur activity batch test showed that 73.80%∼80.92% of sulfate were circulation utilized, and rest of them conversed to the gaseous H2S and S[0]. In addition to DNSOB, anoxic denitrifier of Halomonas (22.91%), aerobic denitrifier of Phaeodactylibacter (2.75%) and endogenous denitrifier of Defluviicoccus (3.18%) were also dominant heterotrophic bacteria (all halophilic or halotolerant) in the intermittent aeration SBBR. Batch activity tests and periodic laws have also verified the existence of corresponding denitrification pathways. This study shows that the enrichment of special halophilic functional bacteria with multiple nitrogen removal pathways is a good idea for the efficient treatment of high-concentrated hypersaline industrial wastewater.}, } @article {pmid32277108, year = {2020}, author = {Cai, YM and Hutchin, A and Craddock, J and Walsh, MA and Webb, JS and Tews, I}, title = {Differential impact on motility and biofilm dispersal of closely related phosphodiesterases in Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {6232}, pmid = {32277108}, issn = {2045-2322}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cyclic GMP/metabolism ; Gene Expression Regulation, Bacterial/physiology ; Genes, Bacterial/*genetics ; Nitric Oxide/metabolism ; Phosphoric Diester Hydrolases/genetics/*metabolism ; Protein Domains ; Pseudomonas aeruginosa/*physiology ; Sequence Deletion ; }, abstract = {In Pseudomonas aeruginosa, the transition between planktonic and biofilm lifestyles is modulated by the intracellular secondary messenger cyclic dimeric-GMP (c-di-GMP) in response to environmental conditions. Here, we used gene deletions to investigate how the environmental stimulus nitric oxide (NO) is linked to biofilm dispersal, focusing on biofilm dispersal phenotype from proteins containing putative c-di-GMP turnover and Per-Arnt-Sim (PAS) sensory domains. We document opposed physiological roles for the genes ΔrbdA and Δpa2072 that encode proteins with identical domain structure: while ΔrbdA showed elevated c-di-GMP levels, restricted motility and promoted biofilm formation, c-di-GMP levels were decreased in Δpa2072, and biofilm formation was inhibited, compared to wild type. A second pair of genes, ΔfimX and ΔdipA, were selected on the basis of predicted impaired c-di-GMP turnover function: ΔfimX showed increased, ΔdipA decreased NO induced biofilm dispersal, and the genes effected different types of motility, with reduced twitching for ΔfimX and reduced swimming for ΔdipA. For all four deletion mutants we find that NO-induced biomass reduction correlates with increased NO-driven swarming, underlining a significant role for this motility in biofilm dispersal. Hence P. aeruginosa is able to differentiate c-di-GMP output using structurally highly related proteins that can contain degenerate c-di-GMP turnover domains.}, } @article {pmid32276211, year = {2020}, author = {Qian, W and Yang, M and Li, X and Sun, Z and Li, Y and Wang, X and Wang, T}, title = {Anti-microbial and anti-biofilm activities of combined chelerythrine-sanguinarine and mode of action against Candida albicans and Cryptococcus neoformans in vitro.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {191}, number = {}, pages = {111003}, doi = {10.1016/j.colsurfb.2020.111003}, pmid = {32276211}, issn = {1873-4367}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Benzophenanthridines/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Cryptococcus neoformans/*drug effects ; Isoquinolines/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Particle Size ; Surface Properties ; }, abstract = {The increasing prevalence of fungal infections coupled with emerging drug resistance has stimulated an urgent need to explore new and effective antifungal agents. Sanguinarine and chelerythrine constitute alkaloids that have exhibited antifungal activities. However, the effects of a 1:1 mixture of these agents against Candida albicans and Cryptococcus neoformans have remained largely unexplored. The purpose of this study was to assess the anti-fungal and anti-biofilm efficacy of combined chelerythrine-sanguinarine against C. albicans and C. neoformans in vitro. Combined chelerythrine-sanguinarine inhibited C. albicans and C. neoformans growth with minimum inhibitory concentrations (MICs) of 2 and 16 μg/mL, respectively, and effectively inhibited adhesion and biofilm formation of these pathogens at minimum biofilm inhibitory concentrations of 1 and 8 μg/mL. Notably, the mixture significantly eradicated mature C. albicans and C. neoformans biofilms at 8 and 128 μg/mL, respectively. In particular, the mixture was found to disrupt cell membrane integrity and enhance penetration of antibiotics into fungal cells, suggesting its antifungal mode of action. Hence, combined chelerythrine-sanguinarine shows promise as a potential anti-fungal and anti-biofilm agent for the management of serious infections caused by C. albicans and C. neoformans.}, } @article {pmid32276085, year = {2020}, author = {Song, X and Pan, H and Wang, H and Liao, X and Sun, D and Xu, K and Chen, T and Zhang, X and Wu, M and Wu, D and Gao, Y}, title = {Identification of new dermaseptins with self-assembly tendency: membrane disruption, biofilm eradication, and infected wound healing efficacy.}, journal = {Acta biomaterialia}, volume = {109}, number = {}, pages = {208-219}, doi = {10.1016/j.actbio.2020.03.024}, pmid = {32276085}, issn = {1878-7568}, mesh = {Amino Acid Sequence ; Amphibian Proteins/chemistry/isolation & purification/*therapeutic use ; Animals ; Anti-Bacterial Agents/chemistry/isolation & purification/*therapeutic use ; Antimicrobial Cationic Peptides/chemistry/isolation & purification/*therapeutic use ; Anura ; Biofilms/drug effects ; Cell Membrane/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Mice, Inbred ICR ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Protein Conformation, alpha-Helical ; Skin/microbiology ; Staphylococcal Infections/*drug therapy ; Wound Healing/*drug effects ; }, abstract = {Severe infections associated with antibiotic-resistant bacteria and biofilms have attracted increasing interest as these diseases are difficult to treat with current antibiotics. Typical cationic antimicrobial peptides dermaseptins are considered to be the most promising next-generation antibiotics because of their broad-spectrum antimicrobial activities and minor side effects. Two new dermaseptin peptides, DMS-PS1 and DMS-PS2, have been identified by "shotgun" molecular cloning of encoding cDNAs in the crude skin secretions of the waxy monkey tree frog, Phyllomedusa sauvagei. The mature peptide sequences predicted from the cloned cDNAs were separated from crude skin secretions and confirmed by mass spectrometry. Chemically synthetic replicates were assessed for various biological activities. Both dermaseptins were potently effective against a broad spectrum of microorganisms including antibiotic-resistant bacteria and displayed significant potency against gram-positive and gram-negative bacterial biofilms with low toxicity towards mammalian red blood cells. Remarkably, DMS-PS2 was effective against infections in murine skin caused by methicillin-resistant Staphylococcus aureus as a result of an induced wound. The actions of DMS-PS2 were with a membrane permeabilization mode. Overall, the data provided convincing evidence for the development of anti-infectious agents and/or biomaterials as a new therapeutic approach against bacterial infections. STATEMENT OF SIGNIFICANCE: Bacterial adhesion to biomaterials remains a major problem. Antimicrobial peptides (AMPs) are well-known components of the innate immune system that can be applied to overcome biofilm-associated infections. Cationic dermaseptin peptides showed significant broad-spectrum antimicrobial activities and activities against bacterial biofilms of persistent infections in association with weak toxicity for mammalian red blood cells. The membrane permeabilizing ability of DMS-PS2 was confirmed, and importantly, it demonstrated potent efficiency of the treatment of MRSA infected murine skin model. Furthermore, beyond our expectation, DMS-PS2 showed a self-aggregating parameter, indicating a promising potential for the use of immobilized AMPs in clinical applications., which makes it also a promising suggestion for infection-proof biomaterial development.}, } @article {pmid32272740, year = {2020}, author = {Guła, G and Szymanowska, P and Piasecki, T and Góras, S and Gotszalk, T and Drulis-Kawa, Z}, title = {The Application of Impedance Spectroscopy for Pseudomonas Biofilm Monitoring during Phage Infection.}, journal = {Viruses}, volume = {12}, number = {4}, pages = {}, pmid = {32272740}, issn = {1999-4915}, mesh = {Biofilms/*growth & development ; Culture Media ; Dielectric Spectroscopy/*methods ; Extracellular Polymeric Substance Matrix/physiology ; Pseudomonas Phages/*physiology ; Pseudomonas aeruginosa/*physiology/*virology ; }, abstract = {Bacterial biofilm prevention and eradication are common treatment problems, hence there is a need for advanced and precise experimental methods for its monitoring. Bacterial resistance to antibiotics has resulted in an interest in using a natural bacterial enemy-bacteriophages. In this study, we present the application of quartz tuning forks (QTF) as impedance sensors to determine in real-time the direct changes in Pseudomonas aeruginosa PAO1 biofilm growth dynamics during Pseudomonas phage LUZ 19 treatment at different multiplicities of infection (MOI). The impedance of the electric equivalent circuit (EEC) allowed us to measure the series resistance (Rs) corresponding to the growth-medium resistance (planktonic culture changes) and the conductance (G) corresponding to the level of QTF sensor surface coverage by bacterial cells and the extracellular polymer structure (EPS) matrix. It was shown that phage impacts on sessile cells (G dynamics) was very similar in the 10-day biofilm development regardless of applied MOI (0.1, 1 or 10). The application of phages at an early stage (at the sixth h) and on three-day biofilm caused a significant slowdown in biofilm dynamics, whereas the two-day biofilm turned out to be insensitive to phage infection. We observed an inhibitory effect of phage infection on the planktonic culture (Rs dynamics) regardless of the MOI applied and the time point of infection. Moreover, the Rs parameter made it possible to detect PAO1 population regrowth at the latest time points of incubation. The number of phage-insensitive forms reached the level of untreated culture at around the sixth day of infection. We conclude that the proposed impedance spectroscopy technique can be used to measure the physiological changes in the biofilm matrix composition, as well as the condition of planktonic cultures in order to evaluate the activity of anti-biofilm compounds.}, } @article {pmid32272414, year = {2020}, author = {Wang, H and Zhang, H and Zhang, K and Qian, Y and Yuan, X and Ji, B and Han, W}, title = {Membrane fouling mitigation in different biofilm membrane bioreactors with pre-anoxic tanks for treating mariculture wastewater.}, journal = {The Science of the total environment}, volume = {724}, number = {}, pages = {138311}, doi = {10.1016/j.scitotenv.2020.138311}, pmid = {32272414}, issn = {1879-1026}, mesh = {Biofilms ; *Biofouling ; Bioreactors ; Membranes, Artificial ; Motor Vehicles ; Sewage ; *Wastewater ; }, abstract = {This study compared the membrane fouling mitigation in two novel types of biofilm membrane bioreactor coupled with a pre-anoxic tank (BF-AO-MBR)-namely a fixed biofilm membrane bioreactor (FB-MBR) with fiber bundle bio-carriers and a moving-bed biofilm membrane bioreactor (MB-MBR) with suspended bio-carriers-relative to an anoxic/oxic MBR (AO-MBR), at salinities ranging from zero to 60 g/L. The results showed that the FB-MBR mitigated membrane fouling to a greater degree than the MB-MBR and AO-MBR. During operation, the FB-MBR exhibited the lowest fouling development, with three membrane filtration cycles, while the AO-MBR and MB-MBR had 22 and nine cycles, respectively. The key fouling factor in all reactors was cake layer resistance (RC), which contributed to 89.61, 62.20, and 83.17% of the total fouling resistance (RT) in AO-MBR, FB-MBR and MB-MBR, respectively. Additionally, in the FB-MBR, the pore blocking resistance (30.07%) was also an important cause of fouling. Fiber bundle bio-carriers and suspended bio-carriers reduced the RT by 37.68% and 21.24% (mainly the RC) compared to that of AO-MBR. Furthermore, FB-MBR and MB-MBR caused a decrease of suspended biomass (80.14 and 15.90%, respectively), and the latter exhibited a higher sludge particle size than AO-MBR, possibly resulting in the cake layer decline. The studied BF-AO-MBRs further alleviated the fouling propensity by reducing the amount of soluble microbial product (SMP) and extracellular polymeric substances (EPS) under all salinity levels, especially the FB-MBR. Among the protein components, the amounts of tryptophan protein-like substance and aromatic protein-like substance were significantly lower in the FB-MBR compared to the AO-MBR and MB-MBR. Additionally, at 60 g/L salinity, the structure of the microbial community in the FB-MBR had a lower abundance of Bacteroidetes and more biomacromolecule degraders, which may have contributed to the moderation of membrane fouling.}, } @article {pmid32272386, year = {2020}, author = {Alves, P and Gomes, LC and Vorobii, M and Rodriguez-Emmenegger, C and Mergulhão, FJ}, title = {The potential advantages of using a poly(HPMA) brush in urinary catheters: effects on biofilm cells and architecture.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {191}, number = {}, pages = {110976}, doi = {10.1016/j.colsurfb.2020.110976}, pmid = {32272386}, issn = {1873-4367}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Coated Materials, Biocompatible/*chemistry ; Escherichia coli/*growth & development ; Escherichia coli Infections/microbiology ; Humans ; Methacrylates/*chemistry ; Polymers/*chemistry ; Surface Properties ; *Urinary Catheters ; }, abstract = {Infections related to bacterial colonization of medical devices are a growing concern given the socio-economical impacts in healthcare systems. Colonization of a device surface with bacteria usually triggers the development of a biofilm, which is more difficult to eradicate than free-floating or adhered bacteria and can act as a reservoir for subsequent infections. Biofilms often harbor Viable but nonculturable (VBNC) cells that are likely to be more resistant to antibiotic treatment and that can become active in more favorable conditions causing infection. Biofilm formation is dependent on different factors, chiefly the properties of the surface and of the surrounding medium, and the hydrodynamic conditions. In this work, the antifouling performance of a poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)) brush was evaluated in vitro in conditions that mimic a urinary catheter using Escherichia coli as a model organism. The results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) (the most common material for catheters) and glass. A decrease in initial adhesion and surface coverage was observed on the brush. This antifouling behavior was maintained during biofilm maturation and even in a simulated post-bladder infection period when the reduction in total cell number reached 87 %. Biofilms were shown to adapt their architecture during that period and VBNC cells adsorbed weakly on the brushes and were completely washed away. Taken together, these results suggest that the use of the poly(HPMA) brush in urinary tract devices such as catheters and stents may reduce biofilm formation and possibly render the formed biofilms more susceptible to antibiotic treatment and with reduced infectivity potential.}, } @article {pmid32272212, year = {2020}, author = {Hamdy, R and Soliman, SSM and Alsaadi, AI and Fayed, B and Hamoda, AM and Elseginy, SA and Husseiny, MI and Ibrahim, AS}, title = {Design and synthesis of new drugs inhibitors of Candida albicans hyphae and biofilm formation by upregulating the expression of TUP1 transcription repressor gene.}, journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences}, volume = {148}, number = {}, pages = {105327}, pmid = {32272212}, issn = {1879-0720}, support = {R01 AI063503/AI/NIAID NIH HHS/United States ; R01 AI141202/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects ; Erythrocytes/drug effects ; Fungal Proteins/*metabolism ; Gene Expression Regulation, Fungal/drug effects ; Hemolysis ; Humans ; Hyphae/*drug effects ; Rhodanine ; Transcription Factors/metabolism ; }, abstract = {Candida albicans is a common human fungal pathogen that causes disease ranging from superficial to lethal infections. C. albicans grows as budding yeast which can transform into hyphae in response to various environmental or biological stimuli. Although both forms have been associated with virulence, the hyphae form is responsible for the formation of multi-drug resistance biofilm. Here, new compounds were designed to selectively inhibit C. albicans hyphae formation without affecting human cells to afford sufficient safety. The newly designed 5-[3-substitued-4-(4-substituedbenzyloxy)-benzylidene]-2-thioxo-thiazolidin-4-one derivatives, named SR, showed very specific and effective inhibition activity against C. albicans hyphae formation. SR compounds caused hyphae inhibition activity at concentrations 10-40 fold lower than the concentration required to inhibit Candida yeast and bacterial growths. The anti-hyphae inhibition activities of SR compounds were via activation of the hyphae transcription repressor gene, TUP1. Correlation studies between the expression of TUP1 gene and the activity of SR compounds confirmed that the anti-C. albicans activities of SR compounds were via inhibition of hyphae formation. The newly designed SR compounds showed 10-40% haemolytic activity on human erythrocytes when compared to 100% haemolysis by 0.1% triton employed as positive control. Furthermore, theoretical prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of SR compounds confirmed their safety, efficient metabolism and possible oral bioavailability. With the minimal toxicity and significant activity of the newly-designed SR compounds, a future optimization of pharmaceutical formulation may develop a promising inhibitor of hyphal formation not only for C. albicans but also for other TUP1- dependent dimorphic fungal infections.}, } @article {pmid32272186, year = {2020}, author = {Iwaki, T and Ohshima, T and Tasaki, T and Momoi, Y and Ikawa, S and Kitano, K and Yamamoto, T}, title = {High microbicidal effect of peroxynitric acid on biofilm-infected dentin in a root carious tooth model and verification of tissue safety.}, journal = {Journal of oral biosciences}, volume = {62}, number = {2}, pages = {189-194}, doi = {10.1016/j.job.2020.03.002}, pmid = {32272186}, issn = {1880-3865}, mesh = {Aged ; Biofilms ; *Dental Caries ; Dentin ; Humans ; Nitrates ; Streptococcus mutans ; }, abstract = {OBJECTIVES: Root-caries, which frequently occurs in elderly people, is more difficult to treat than caries in a tooth crown, especially in filling restorations. To overcome this difficulty, it is essential to find a strategy for sufficiently sterilizing the infected dentin; however, techniques for sterilizing carious pathogens inside the biofilm, called dental plaque, have not yet been established. Recently, dental applications of plasma sterilization technology have attracted attention. The mechanism of plasma sterilization became clear, and revealed that peroxynitric acid (PNA) is an effective sterilization substance. Highly concentrated PNA solutions can be chemically synthesized in large quantities without using plasma technology. We thought that the application of PNA solution could be a novel treatment for root caries, and examined the microbicidal effect and safety of PNA.

METHODS: A sterilization experiment was performed using an extracted tooth model infected with Streptococcus mutans. Subsequently, a biofilm of S. mutans and Candida albicans was formed on a plate or a dentin slice, and sterilization experiments were performed in comparison with chlorhexidine. Furthermore, a toxicity test of PNA was performed using an epithelial tissue model.

RESULTS: In the infection model, sterilization was achieved with a 22 mM PNA solution in only 10 s. In the biofilm model, a 22 mM PNA solution showed a higher microbicidal effect than 2.0% chlorhexidine. In the toxicity test, 2.0% chlorhexidine was toxic, but a 220 mM PNA solution showed no toxicity.

CONCLUSIONS: PNA is an unprecedented disinfectant that has high microbicidal activity on biofilm and is safe for tissues.}, } @article {pmid32269377, year = {2020}, author = {Tan, D and Hansen, MF and de Carvalho, LN and Røder, HL and Burmølle, M and Middelboe, M and Svenningsen, SL}, title = {High cell densities favor lysogeny: induction of an H20 prophage is repressed by quorum sensing and enhances biofilm formation in Vibrio anguillarum.}, journal = {The ISME journal}, volume = {14}, number = {7}, pages = {1731-1742}, pmid = {32269377}, issn = {1751-7370}, mesh = {Animals ; Biofilms ; Cell Count ; *Lysogeny ; *Prophages/genetics ; Quorum Sensing ; Vibrio ; }, abstract = {Temperate ϕH20-like phages are repeatedly identified at geographically distinct areas as free phage particles or as prophages of the fish pathogen Vibrio anguillarum. We studied mutants of a lysogenic isolate of V. anguillarum locked in the quorum-sensing regulatory modes of low (ΔvanT) and high (ΔvanO) cell densities by in-frame deletion of key regulators of the quorum-sensing pathway. Remarkably, we find that induction of the H20-like prophage is controlled by the quorum-sensing state of the host, with an eightfold increase in phage particles per cell in high-cell-density cultures of the quorum-sensing-deficient ΔvanT mutant. Comparative studies with prophage-free strains show that biofilm formation is promoted at low cell density and that the H20-like prophage stimulates this behavior. In contrast, the high-cell-density state is associated with reduced prophage induction, increased proteolytic activity, and repression of biofilm. The proteolytic activity may dually function to disperse the biofilm and as a quorum-sensing-mediated antiphage strategy. We demonstrate an intertwined regulation of phage-host interactions and biofilm formation, which is orchestrated by host quorum-sensing signaling, suggesting that increased lysogeny at high cell density is not solely a strategy for phages to piggy-back the successful bacterial hosts but is also a host strategy evolved to take control of the lysis-lysogeny switch to promote host fitness.}, } @article {pmid32268566, year = {2020}, author = {Fontecha-Umaña, F and Ríos-Castillo, AG and Ripolles-Avila, C and Rodríguez-Jerez, JJ}, title = {Antimicrobial Activity and Prevention of Bacterial Biofilm Formation of Silver and Zinc Oxide Nanoparticle-Containing Polyester Surfaces at Various Concentrations for Use.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32268566}, issn = {2304-8158}, support = {RTI2018-098267-R-C32//Ministerio de Ciencia, Innovación y Universidades/ ; }, abstract = {Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm[2]) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm[2]). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm[2]) and S. aureus (3.84 log CFU/cm[2]). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm[2]) and S. aureus (4.11 log CFU/cm[2]). The results also showed a high correlation between concentration levels and the bacterial activity of Ag-ZnO-NPs (R[2] = 0.97 for S. aureus, and R[2] = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.}, } @article {pmid32267888, year = {2020}, author = {Karbysheva, S and Di Luca, M and Butini, ME and Winkler, T and Schütz, M and Trampuz, A}, title = {Comparison of sonication with chemical biofilm dislodgement methods using chelating and reducing agents: Implications for the microbiological diagnosis of implant associated infection.}, journal = {PloS one}, volume = {15}, number = {4}, pages = {e0231389}, pmid = {32267888}, issn = {1932-6203}, mesh = {Bacteria/drug effects/*isolation & purification ; Bacterial Load/methods ; Biofilms/*drug effects ; Calorimetry ; Chelating Agents/*pharmacology ; Dithiothreitol/pharmacology ; Edetic Acid/pharmacology ; Escherichia coli/isolation & purification/physiology ; Humans ; Microscopy, Electron, Scanning ; Prosthesis-Related Infections/*diagnosis/microbiology ; Pseudomonas aeruginosa/isolation & purification/physiology ; Reducing Agents/chemistry/*pharmacology ; Sodium Chloride/pharmacology ; *Sonication ; Staphylococcus aureus/isolation & purification/physiology ; Staphylococcus epidermidis/isolation & purification/physiology ; }, abstract = {The diagnosis of implant-associated infections is hampered due to microbial adherence and biofilm formation on the implant surface. Sonication of explanted devices was shown to improve the microbiological diagnosis by physical removal of biofilms. Recently, chemical agents have been investigated for biofilm dislodgement such as the chelating agent ethylenediaminetetraacetic acid (EDTA) and the reducing agent dithiothreitol (DTT). We compared the activity of chemical methods for biofilm dislodgement to sonication in an established in vitro model of artificial biofilm. Biofilm-producing laboratory strains of Staphylococcus epidermidis (ATCC 35984), S. aureus (ATCC 43300), E. coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 53278) were used. After 3 days of biofilm formation, porous glass beads were exposed to control (0.9% NaCl), sonication or chemical agents. Quantitative and qualitative biofilm analyses were performed by colony counting, isothermal microcalorimetry and scanning electron microscopy. Recovered colony counts after treatment with EDTA and DTT were similar to those after exposure to 0.9% NaCl for biofilms of S. epidermidis (6.3 and 6.1 vs. 6.0 log10 CFU/mL, S. aureus (6.4 and 6.3 vs. 6.3 log10 CFU/mL), E. coli (5.2 and 5.1 vs. 5.1 log10 CFU/mL and P. aeruginosa (5.1 and 5.2 vs. 5.0 log10 CFU/mL, respectively). In contrast, with sonication higher CFU counts were detected with all tested microorganisms (7.5, 7.3, 6.2 and 6.5 log10 CFU/mL, respectively) (p <0.05). Concordant results were observed with isothermal microcalorimetry and scanning electron microscopy. In conclusion, sonication is superior to both tested chemical methods (EDTA and DTT) for dislodgement of S. epidermidis, S. aureus, E. coli and P. aeruginosa biofilms. Future studies may evaluate potential additive effect of chemical dislodgement to sonication.}, } @article {pmid32266235, year = {2020}, author = {McGivney, E and Cederholm, L and Barth, A and Hakkarainen, M and Hamacher-Barth, E and Ogonowski, M and Gorokhova, E}, title = {Rapid Physicochemical Changes in Microplastic Induced by Biofilm Formation.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {205}, pmid = {32266235}, issn = {2296-4185}, abstract = {Risk assessment of microplastic (MP) pollution requires understanding biodegradation processes and related changes in polymer properties. In the environment, there are two-way interactions between the MP properties and biofilm communities: (i) microorganisms may prefer some surfaces, and (ii) MP surface properties change during the colonization and weathering. In a 2-week experiment, we studied these interactions using three model plastic beads (polyethylene [PE], polypropylene [PP], and polystyrene [PS]) exposed to ambient bacterioplankton assemblage from the Baltic Sea; the control beads were exposed to bacteria-free water. For each polymer, the physicochemical properties (compression, crystallinity, surface chemistry, hydrophobicity, and surface topography) were compared before and after exposure under controlled laboratory conditions. Furthermore, we characterized the bacterial communities on the MP surfaces using 16S rRNA gene sequencing and correlated community diversity to the physicochemical properties of the MP. Significant changes in PE crystallinity, PP stiffness, and PS maximum compression were observed as a result of exposure to bacteria. Moreover, there were significant correlations between bacterial diversity and some physicochemical characteristics (crystallinity, stiffness, and surface roughness). These changes coincided with variation in the relative abundance of unique OTUs, mostly related to the PE samples having significantly higher contribution of Sphingobium, Novosphingobium, and uncultured Planctomycetaceae compared to the other test materials, whereas PP and PS samples had significantly higher abundance of Sphingobacteriales and Alphaproteobacteria, indicating possible involvement of these taxa in the initial biodegradation steps. Our findings demonstrate measurable signs of MP weathering under short-term exposure to environmentally relevant microbial communities at conditions resembling those in the water column. A systematic approach for the characterization of the biodegrading capacity in different systems will improve the risk assessment of plastic litter in aquatic environments.}, } @article {pmid32260576, year = {2020}, author = {Shafeeq, S and Wang, X and Lünsdorf, H and Brauner, A and Römling, U}, title = {Draft Genome Sequence of the Urinary Catheter Isolate Enterobacter ludwigii CEB04 with High Biofilm Forming Capacity.}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32260576}, issn = {2076-2607}, support = {634588.//Horizon 2020 Framework Programme/ ; }, abstract = {: Enterobacter ludwigii is a fermentative Gram-negative environmental species and accidental human pathogen that belongs to the Enterobacter cloacae complex with the general characteristics of the genus Enterobacter. The clinical isolate E. ludwigii CEB04 was derived from a urinary tract catheter of an individual not suffering from catheter-associated urinary tract infection. The draft genome sequence of the high biofilm forming E. ludwigii CEB04 was determined by PacBio sequencing. The chromosome of E. ludwigii CEB04 is comprised of one contig of 4,892,375 bps containing 4596 predicted protein-coding genes and 120 noncoding RNAs. E. ludwigii CEB04 harbors several antimicrobial resistance markers and has an extended cyclic-di-GMP signaling network compared to Escherichia coli K-12.}, } @article {pmid32260420, year = {2020}, author = {Jouneghani, RS and Castro, AHF and Panda, SK and Swennen, R and Luyten, W}, title = {Antimicrobial Activity of Selected Banana Cultivars Against Important Human Pathogens, Including Candida Biofilm.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32260420}, issn = {2304-8158}, abstract = {Ten banana (Musa spp.) cultivars were studied for their antimicrobial properties. Three plant parts (corm, pseudostem and leaves) were collected separately and extracted with different solvents, viz., hexane, acetone, ethanol and water. The 50% inhibitory concentration (IC50) was evaluated using a broth microdilution assay. Eight human bacterial and one fungal pathogen were tested. Acetone and ethanol extract(s) often exhibited significant antimicrobial activity, while hexane extracts were less active. Aqueous extracts often showed microbial growth, possibly by endophytes. Leaf extracts were most active, followed by pseudostem, and corm was least active. All the tested banana cultivars were found to contain antimicrobials, as demonstrated by inhibition of selected human pathogens. However, cultivars such as Dole, Saba, Fougamou, Namwah Khom, Pelipita and Mbwazirume showed a broad-spectrum activity, inhibiting all tested pathogens. Other cultivars such as Petit Naine and Kluai Tiparot showed a narrow-spectrum activity, including antibiofilm activity against Candida albicans. Our results support the use of different parts of banana plants in traditional human medicine for infections, including diarrhea and dysentery, and some sexually transmitted diseases, as well as for packaging spoilable materials like food.}, } @article {pmid32260416, year = {2020}, author = {Chen, L and Tang, ZY and Cui, SY and Ma, ZB and Deng, H and Kong, WL and Yang, LW and Lin, C and Xiong, WG and Zeng, ZL}, title = {Biofilm Production Ability, Virulence and Antimicrobial Resistance Genes in Staphylococcus aureus from Various Veterinary Hospitals.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32260416}, issn = {2076-0817}, support = {2018YFD0500300//the National Key R&D Program of China/ ; }, abstract = {: Staphylococcus aureus (S. aureus) is one of the most clinically important zoonotic pathogens, but an understanding of the prevalence, biofilm formulation ability, virulence, and antimicrobial resistance genes of S. aureus from veterinary hospitals is lacking. By characterizing S. aureus in different origins of veterinary hospitals in Guangzhou, China, in 2019, we identified with the presence of S. aureus in pets (17.1%), veterinarians (31.7%), airborne dust (19.1%), environmental surfaces (4.3%), and medical device surfaces (10.8%). Multilocus sequence typing (MLST) and Staphylococcus protein A (spa) typing analyses demonstrated methicillin-sensitive S. aureus (MSSA) ST398-t571, MSSA ST188-t189, and methicillin-resistant S. aureus (MRSA) ST59-t437 were the most prevalent lineage. S. aureus with similar pulsed-field gel electrophoresis (PFGE) types distributed widely in different kinds of samples. The crystal violet straining assays revealed 100% (3/3) of MRSA ST59 and 81.8% (9/11) of MSSA ST188 showed strong biofilm formulation ability, whereas other STs (ST1, ST5, ST7, ST15, ST88, ST398, ST3154 and ST5353) showed weak biofilm production ability. Polymerase chain reaction (PCR) confirmed the most prevalent leucocidin, staphylococcal enterotoxins, ica operon, and adhesion genes were lukD-lukE (49.0%), sec-sel (15.7%), icaA-icaB-icaC-icaR (100.0%), and fnbB-cidA-fib-ebps-eno (100.0%), respectively. Our study showed that the isolates with strong biofilm production ability had a higher prevalence in clfA, clfB, fnbA and sdrC genes compared to the isolates with weak biofilm production ability. Furthermore, 2 ST1-MRSA isolates with tst gene and 1 ST88-MSSA isolate with lukS/F-PV gene were detected. In conclusion, the clonal dissemination of S. aureus of different origins in veterinary hospitals may have occurred; the biofilm production capacity of S. aureus is strongly correlated with ST types; some adhesion genes such as clfA, clfB, fnbA, and sdrC may pose an influence on biofilm production ability and the emergence of lukS/F-PV and tst genes in S. aureus from veterinary hospitals should raise our vigilance.}, } @article {pmid32260245, year = {2020}, author = {Karkowska-Kuleta, J and Surowiec, M and Gogol, M and Koziel, J and Potempa, B and Potempa, J and Kozik, A and Rapala-Kozik, M}, title = {Peptidylarginine Deiminase of Porphyromonas gingivalis Modulates the Interactions between Candida albicans Biofilm and Human Plasminogen and High-Molecular-Mass Kininogen.}, journal = {International journal of molecular sciences}, volume = {21}, number = {7}, pages = {}, pmid = {32260245}, issn = {1422-0067}, support = {R01 DE022597/DE/NIDCR NIH HHS/United States ; 2015/17/B/NZ6/02078//National Science Centre of Poland/ ; }, mesh = {Bacterial Proteins/pharmacology ; Biofilms/drug effects ; Candida albicans/drug effects/*physiology ; Chromatography, Liquid ; Citrullination ; Fungal Proteins/*metabolism ; Humans ; Immunity, Innate ; Kininogens/chemistry/*metabolism ; Plasminogen/*metabolism ; Porphyromonas gingivalis/*enzymology ; Protein Binding ; Protein-Arginine Deiminases/*pharmacology ; Tandem Mass Spectrometry ; }, abstract = {Microorganisms that create mixed-species biofilms in the human oral cavity include, among others, the opportunistic fungus Candida albicans and the key bacterial pathogen in periodontitis, Porphyromonas gingivalis. Both species use arsenals of virulence factors to invade the host organism and evade its immune system including peptidylarginine deiminase that citrullinates microbial and host proteins, altering their function. We assessed the effects of this modification on the interactions between the C. albicans cell surface and human plasminogen and kininogen, key components of plasma proteolytic cascades related to the maintenance of hemostasis and innate immunity. Mass spectrometry was used to identify protein citrullination, and microplate tests to quantify the binding of modified plasminogen and kininogen to C. albicans cells. Competitive radioreceptor assays tested the affinity of citrullinated kinins to their specific cellular receptors. The citrullination of surface-exposed fungal proteins reduced the level of unmodified plasminogen binding but did not affect unmodified kininogen binding. However, the modification of human proteins did not disrupt their adsorption to the unmodified fungal cells. In contrast, the citrullination of kinins exerted a significant impact on their interactions with cellular receptors reducing their affinity and thus affecting the role of kinin peptides in the development of inflammation.}, } @article {pmid32260180, year = {2020}, author = {Ramos, LS and Mello, TP and Branquinha, MH and Santos, ALS}, title = {Biofilm Formed by Candida haemulonii Species Complex: Structural Analysis and Extracellular Matrix Composition.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {6}, number = {2}, pages = {}, pmid = {32260180}, issn = {2309-608X}, support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 002//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 003//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; }, abstract = {Candida haemulonii species complex (C. haemulonii, C. duobushaemulonii, and C. haemulonii var. vulnera) has emerged as opportunistic, multidrug-resistant yeasts able to cause fungemia. Previously, we showed that C. haemulonii complex formed biofilm on polystyrene. Biofilm is a well-known virulence attribute of Candida spp. directly associated with drug resistance. In the present study, the architecture and the main extracellular matrix (ECM) components forming the biofilm over polystyrene were investigated in clinical isolates of the C. haemulonii complex. We also evaluated the ability of these fungi to form biofilm on catheters used in medical arena. The results revealed that all fungi formed biofilms on polystyrene after 48 h at 37 °C. Microscopic analyses demonstrated a dense network of yeasts forming the biofilm structure, with water channels and ECM. Regarding ECM, proteins and carbohydrates were the main components, followed by nucleic acids and sterols. Mature biofilms were also detected on late bladder (siliconized latex), nasoenteric (polyurethane), and nasogastric (polyvinyl chloride) catheters, with the biomasses being significantly greater than on polystyrene. Collectively, our results demonstrated the ability of the C. haemulonii species complex to form biofilm on different types of inert surfaces, which is an incontestable virulence attribute associated with devices-related candidemia in hospitalized individuals.}, } @article {pmid32259432, year = {2020}, author = {Liu, G and Zhang, Y and Liu, X and Hammes, F and Liu, WT and Medema, G and Wessels, P and van der Meer, W}, title = {360-Degree Distribution of Biofilm Quantity and Community in an Operational Unchlorinated Drinking Water Distribution Pipe.}, journal = {Environmental science & technology}, volume = {54}, number = {9}, pages = {5619-5628}, pmid = {32259432}, issn = {1520-5851}, mesh = {Bacteria ; Biofilms ; *Drinking Water ; Water Microbiology ; Water Supply ; }, abstract = {In the present study, triplicate rings of 360° pipe surfaces of an operational drinking water distribution pipe were swabbed. Each ring was equally divided into 16 parts for swabbing. The collected swabs were grouped into 3 sections and compared with the biofilm samples sampled by sonication of specimens from the same pipe. The results showed that the biofilm is unevenly distributed over the 16 parts and the 3 sections of the pipe surface. Both the active biomass and the number of observed OTUs increased as the measurements proceeded from the top to the bottom of the pipe. The bacterial community was dominated in all sections by Proteobacteria. At the genus level, Nitrospira spp., Terrimonas spp., and Hyphomicrobium spp. were dominant in all sections. Gaiella spp. and Vicinamibacter spp. dominated in S-I, Blastopirellula spp. and Pirellula spp. dominated in S-II, while Holophaga spp. and Phaeodactylibacter spp. dominated in S-III. When swabbing and pipe specimen sonication were compared, the results showed that the sampling strategy significantly influences the obtained biofilm bacterial community. A consistent multisectional swabbing strategy is proposed for future biofilm sampling; it involves collecting swabs from all sections and comparing the swabs from the same position/section across locations.}, } @article {pmid32259408, year = {2020}, author = {Contreras-Guerrero, P and Ortiz-Magdaleno, M and Urcuyo-Alvarado, MS and Cepeda-Bravo, JA and Leyva-Del Rio, D and Pérez-López, JE and Romo-Ramírez, GF and Sánchez-Vargas, LO}, title = {Effect of dental restorative materials surface roughness on the in vitro biofilm formation of Streptococcus mutans biofilm.}, journal = {American journal of dentistry}, volume = {33}, number = {2}, pages = {59-63}, pmid = {32259408}, issn = {0894-8275}, mesh = {Biofilms ; Ceramics ; Computer-Aided Design ; *Dental Materials ; Dental Porcelain ; Materials Testing ; *Streptococcus mutans ; Surface Properties ; }, abstract = {PURPOSE: To evaluate Streptococcus mutans biofilm formation over different restorative dental materials.

METHODS: Using a bioreactor over 72 hours, four commercially available ceramics were evaluated: IPS E-max Press, IPS E-max CAD, Lava Ultimate CAD-CAM, Vita Enamic and two resin composites (SR Nexco Paste and Brilliant NG). The results were evaluated using atomic force microscopy and confocal microscopy, the biofilm was stained and the arbitrary fluorescence units (AFU) quantified.

RESULTS: The results showed that IPS E-max CAD had the lowest roughness values (4.29±1.79 nm), while the highest values were observed for Vita Enamic discs ((77.13±17.35 nm). Analysis of S. mutans biofilm formation by AFU revealed lower values for IPS E-max CAD (6.77±1.67 nm); the highest values were found for Lava Ultimate (79.99±22.23 nm). Regarding the composite groups, SR Nexco Paste showed roughness values of 15.07±2.77 nm and lower arbitrary fluorescence units of 30.92±12.01 nm than Brilliant NT. There was a correlation between the surface roughness of ceramics and composite with S. mutans biofilm formation.

CLINICAL SIGNIFICANCE: The adhesion of oral bacteria to restorative dental materials plays a key role in the success of dental treatment; the surface roughness influences the S. mutans biofilm formation.}, } @article {pmid32259407, year = {2020}, author = {Ishizawa, M and Tomiyama, K and Hasegawa, H and Hamada, N and Mukai, Y}, title = {Comprehensive analysis of bacterial flora of a biofilm model in initial caries-inducing environment.}, journal = {American journal of dentistry}, volume = {33}, number = {2}, pages = {55-58}, pmid = {32259407}, issn = {0894-8275}, mesh = {Adult ; Bacteria ; Biofilms ; *Dental Caries ; Humans ; Saliva ; Streptococcus mutans ; Sucrose ; }, abstract = {PURPOSE: To analyze changes in pH and bacterial flora with duration of culture and timing of sugar supply using a polymicrobial biofilm model.

METHODS: The biofilm was prepared using the method of Exterkate et al. Stimulated saliva from an adult was collected on a glass slide and added to unbuffered McBain medium containing 0.2% sucrose and cultivated under anaerobic conditions for 10 hours. Cultivation continued anaerobically in saliva-free medium refreshed twice daily, with or without sucrose, in five groups: in the Control and Groups A and C, with 0.2% sucrose for 96, 192 and 288 hours, respectively; in Groups B and E, with 0.2% sucrose for 96 hours then, respectively, without for 96 and 192 hours; in Group D, with 0.2% sucrose for 96 hours, without for 96 hours, then with for 96 hours. The pH of all spent medium was measured. Total bacteria counts were determined by Q-PCR. The bacterial composition was determined by next-generation sequencing of 16S rDNA.

RESULTS: The pH of spent medium depended on the presence or absence of sucrose. Total bacteria counts were higher in A, C and D than the other groups, and markedly lower in Group E. Principal components analysis and cluster analysis showed wider variation of bacterial flora of the biofilm in Groups B, D and E than other groups.

CLINICAL SIGNIFICANCE: Inspection of bacterial flora of a biofilm model of the initial caries-inducing environment may lead to the development of materials and procedures for the prevention of dental caries.}, } @article {pmid32257646, year = {2020}, author = {Li, W and Xue, M and Yu, L and Qi, K and Ni, J and Chen, X and Deng, R and Shang, F and Xue, T}, title = {QseBC is involved in the biofilm formation and antibiotic resistance in Escherichia coli isolated from bovine mastitis.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e8833}, pmid = {32257646}, issn = {2167-8359}, abstract = {BACKGROUND: Mastitis is one of the most common infectious diseases in dairy cattle and causes significant financial losses in the dairy industry worldwide. Antibiotic therapy has been used as the most effective strategy for clinical mastitis treatment. However, due to the extensive use of antibacterial agents, antimicrobial resistance (AMR) is considered to be one of the reasons for low cure rates in bovine mastitis. In addition, biofilms could protect bacteria by restricting antibiotic access and shielding the bacterial pathogen from mammary gland immune defences. The functional mechanisms of quorum sensing E. coli regulators B an d C (QseBC) have been well studied in E. coli model strains; however, whether QseBC regulates antibiotic susceptibility and biofilm formation in clinical E. coli strain has not been reported.

METHODS: In this study, we performed construction of the qseBC gene mutant, complementation of the qseBC mutant, antimicrobial susceptibility testing, antibacterial activity assays, biofilm formation assays, real-time reverse transcription PCR (RT-PCR) experiments and electrophoretic mobility shift assays (EMSAs) to investigate the role of qseBC in regulating biofilm formation and antibiotic susceptibility in the clinical E. coli strain ECDCM2.

RESULTS: We reported that inactivation of QseBC led to a decrease in biofilm formation capacity and an increase in antibiotic susceptibility of an E. coli strain isolated from a dairy cow that suffered from mastitis. In addition, this study indicated that QseBC increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, csgA, fliC, motA, wcaF and fimA and decreased antibiotic susceptibility by upregulating the transcription of the efflux-pump-associated genes marA, acrA, acrB, acrD, emrD and mdtH. We also performed EMSA assays, and the results showed that QseB can directly bind to the marA promoter.

CONCLUSIONS: The QseBC two-component system affects antibiotic sensitivity by regulating the transcription of efflux-pump-associated genes. Further, biofilm-formation-associated genes were also regulated by QseBC TCS in E. coli ECDCM2. Hence, this study might provide new clues to the prevention and treatment of infections caused by the clinical E. coli strains.}, } @article {pmid32256460, year = {2020}, author = {Khoury, ZH and Vila, T and Puthran, TR and Sultan, AS and Montelongo-Jauregui, D and Melo, MAS and Jabra-Rizk, MA}, title = {The Role of Candida albicans Secreted Polysaccharides in Augmenting Streptococcus mutans Adherence and Mixed Biofilm Formation: In vitro and in vivo Studies.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {307}, pmid = {32256460}, issn = {1664-302X}, support = {R21 DE028693/DE/NIDCR NIH HHS/United States ; }, abstract = {The oral cavity is a complex environment harboring diverse microbial species that often co-exist within biofilms formed on oral surfaces. Within a biofilm, inter-species interactions can be synergistic in that the presence of one organism generates a niche for another enhancing colonization. Among these species are the opportunistic fungal pathogen Candida albicans and the bacterial species Streptococcus mutans, the etiologic agents of oral candidiasis and dental caries, respectively. Recent studies have reported enhanced prevalence of C. albicans in children with caries indicating potential clinical implications for this fungal-bacterial interaction. In this study, we aimed to specifically elucidate the role of C. albicans-derived polysaccharide biofilm matrix components in augmenting S. mutans colonization and mixed biofilm formation. Comparative evaluations of single and mixed species biofilms demonstrated significantly enhanced S. mutans retention in mixed biofilms with C. albicans. Further, S. mutans single species biofilms were enhanced upon exogenous supplementation with purified matrix material derived from C. albicans biofilms. Similarly, growth in C. albicans cell-free spent biofilm culture media enhanced S. mutans single species biofilm formation, however, the observed increase in S. mutans biofilms was significantly affected upon enzymatic digestion of polysaccharides in spent media, identifying C. albicans secreted polysaccharides as a key factor in mediating mixed biofilm formation. The enhanced S. mutans biofilms mediated by the various C. albicans effectors was also demonstrated using confocal laser scanning microscopy. Importantly, a clinically relevant mouse model of oral co-infection was adapted to demonstrate the C. albicans-mediated enhanced S. mutans colonization in a host. Analyses of harvested tissue and scanning electron microscopy demonstrated significantly higher S. mutans retention on teeth and tongues of co-infected mice compared to mice infected only with S. mutans. Collectively, the findings from this study strongly indicate that the secretion of polysacharides from C. albicans in the oral environment may impact the development of S. mutans biofilms, ultimately increasing dental caries and, therefore, Candida oral colonization should be considered as a factor in evaluating the risk of caries.}, } @article {pmid32256266, year = {2020}, author = {Abdulhaq, N and Nawaz, Z and Zahoor, MA and Siddique, AB}, title = {Association of biofilm formation with multi drug resistance in clinical isolates of Pseudomonas aeruginosa.}, journal = {EXCLI journal}, volume = {19}, number = {}, pages = {201-208}, pmid = {32256266}, issn = {1611-2156}, abstract = {Pseudomonas aeruginosa is considered as foremost cause of hospital acquired infections due to its innate and plasmid mediated resistance to multiple antibiotics making it a multi drug resistant (MDR) pathogen. Biofilm formation is a pathogenic mechanism harbored by this pathogen which further elevates its resistance to antibiotics and host defense system. The aim of the present study was to evaluate the biofilm forming potential and distribution of pslA gene in multi drug resistant Pseudomonas aeruginosa isolates obtained from different clinical samples. A total of 200 different clinical samples were collected after obtaining written consent from the patients. The samples were subjected to isolation and identification of P. aeruginosa by standard microbiological procedures. Confirmation of isolates was done by polymerase chain reaction targeting oprL gene. Kirby Bauer method was performed for detection of MDR isolates. Congo red agar (CRA) test and Microtiter plate assay (MPA) for observing the biofilm forming ability and amplification of pslA gene was also performed on MDR isolates. The results showed that from 200 samples 52 (26 %) were P. aeruginosa and among them 20 (38.46 %) were MDR isolates. The CRA showed 23 (44.23 %) while MPA detected 49 (94.23 %) isolates as biofilm producers while all the MDR isolates showed biofilm formation by MPA method. The pslA gene was detected in all biofilm forming isolates while 90 % in MDR P. aeruginosa. It was concluded that biofilm forming P. aeruginosa are more resistant to tested antibiotics and biofilm formation is strongly associated with presence of pslA gene.}, } @article {pmid32256169, year = {2020}, author = {Al-Shabib, NA and Husain, FM and Rehman, MT and Alyousef, AA and Arshad, M and Khan, A and Masood Khan, J and Alam, P and Albalawi, TA and Shahzad, SA and Syed, JB and Al-Ajmi, MF}, title = {Food color 'Azorubine' interferes with quorum sensing regulated functions and obliterates biofilm formed by food associated bacteria: An in vitro and in silico approach.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {4}, pages = {1080-1090}, pmid = {32256169}, issn = {1319-562X}, abstract = {Quorum sensing (QS) plays a crucial role in different stages of biofilm development, virulence production, and subsequently to the growth of bacteria in food environments. Biofilm mediated spoilage of food is one of the ongoing challenge faced by the food industry worldwide as it incurs substantial economic losses and leads to various health issues. In the present investigation, we studied the interference of quorum sensing, its regulated virulence functions, and biofilm in food-associated bacteria by colorant azorubine. In vitro bioassays demonstrated significant inhibition of QS and its coordinated virulence functions in Chromobacterium violaceum 12472 (violacein) and Pseudomonas aeruginosa PAO1 (elastase, protease, pyocyanin, and alginate). Further, the decrease in the production EPS (49-63%) and swarming motility (61-83%) of the pathogens was also recorded at sub-MICs. Azorubine demonstrated broad-spectrum biofilm inhibitory potency (50-65%) against Chromobacterium violaceum, Pseudomonas aeruginosa, E. coli O157:H7, Serratia marcescens, and Listeria monocytogenes. ROS generation due to the interaction between bacteria and azorubine could be responsible for the biofilm inhibitory action of the food colorant. Findings of the in vitro studies were well supported by molecular docking and simulation analysis of azorubine and QS virulence proteins. Azorubine showed strong binding to PqsA as compared to other virulent proteins (LasR, Vfr, and QscR). Thus, it is concluded that azorubine is a promising candidate to ensure food safety by curbing the menace of bacterial QS and biofilm-based spoilage of food and reduce economic losses.}, } @article {pmid32255642, year = {2021}, author = {Arias, SL and Devorkin, J and Civantos, A and Allain, JP}, title = {Escherichia coli Adhesion and Biofilm Formation on Polydimethylsiloxane are Independent of Substrate Stiffness.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {37}, number = {1}, pages = {16-25}, doi = {10.1021/acs.langmuir.0c00130}, pmid = {32255642}, issn = {1520-5827}, mesh = {*Bacterial Adhesion ; Biofilms ; Dimethylpolysiloxanes ; *Escherichia coli ; Humans ; Surface Properties ; }, abstract = {Bacterial adhesion and biofilm formation on the surface of biomedical devices are detrimental processes that compromise patient safety and material functionality. Several physicochemical factors are involved in biofilm growth, including the surface properties. Among these, material stiffness has recently been suggested to influence microbial adhesion and biofilm growth in a variety of polymers and hydrogels. However, no clear consensus exists about the role of material stiffness in biofilm initiation and whether very compliant substrates are deleterious to bacterial cell adhesion. Here, by systematically tuning substrate topography and stiffness while keeping the surface free energy of polydimethylsiloxane substrates constant, we show that topographical patterns at the micron and submicron scale impart unique properties to the surface which are independent of the material stiffness. The current work provides a better understanding of the role of material stiffness in bacterial physiology and may constitute a cost-effective and simple strategy to reduce bacterial attachment and biofilm growth even in very compliant and hydrophobic polymers.}, } @article {pmid32252300, year = {2020}, author = {Flannery, A and Le Berre, M and Pier, GB and O'Gara, JP and Kilcoyne, M}, title = {Glycomics Microarrays Reveal Differential In Situ Presentation of the Biofilm Polysaccharide Poly-N-acetylglucosamine on Acinetobacter baumannii and Staphylococcus aureus Cell Surfaces.}, journal = {International journal of molecular sciences}, volume = {21}, number = {7}, pages = {}, pmid = {32252300}, issn = {1422-0067}, support = {Postgraduate Scholarship award//Irish Research Council/ ; Analytical Chemistry Trust Fund Fellowship 2018//Royal Society of Chemistry/ ; HRA-POR-2015-1158/HRBI_/Health Research Board/Ireland ; }, mesh = {Acetylglucosamine/metabolism ; Acinetobacter baumannii/*metabolism ; Bacterial Outer Membrane/metabolism ; *Biofilms ; *Glycomics/methods ; Humans ; *Microarray Analysis/methods ; Models, Biological ; Molecular Structure ; Polysaccharides, Bacterial/chemistry/*metabolism ; Staphylococcus aureus/*metabolism ; Virulence Factors/metabolism ; }, abstract = {The biofilm component poly-N-acetylglucosamine (PNAG) is an important virulence determinant in medical-device-related infections caused by ESKAPE group pathogens including Gram-positive Staphylococcus aureus and Gram-negative Acinetobacter baumannii. PNAG presentation on bacterial cell surfaces and its accessibility for host interactions are not fully understood. We employed a lectin microarray to examine PNAG surface presentation and interactions on methicillin-sensitive (MSSA) and methicillin-resistant S. aureus (MRSA) and a clinical A. baumannii isolate. Purified PNAG bound to wheatgerm agglutinin (WGA) and succinylated WGA (sWGA) lectins only. PNAG was the main accessible surface component on MSSA but was relatively inaccessible on the A. baumannii surface, where it modulated the presentation of other surface molecules. Carbohydrate microarrays demonstrated similar specificities of S. aureus and A. baumannii for their most intensely binding carbohydrates, including 3' and 6'sialyllactose, but differences in moderately binding ligands, including blood groups A and B. An N-acetylglucosamine-binding lectin function which binds to PNAG identified on the A. baumannii cell surface may contribute to biofilm structure and PNAG surface presentation on A. baumannii. Overall, these data indicated differences in PNAG presentation and accessibility for interactions on Gram-positive and Gram-negative cell surfaces which may play an important role in biofilm-mediated pathogenesis.}, } @article {pmid32252278, year = {2020}, author = {Bissong, MEA and Ateba, CN}, title = {Genotypic and Phenotypic Evaluation of Biofilm Production and Antimicrobial Resistance in Staphylococcus aureus Isolated from Milk, North West Province, South Africa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32252278}, issn = {2079-6382}, support = {0000//North-West University/ ; }, abstract = {Background: Biofilm formation in S. aureus may reduce the rate of penetration of antibiotics, thereby complicating treatment of infections caused by these bacteria. The aim of this study was to correlate biofilm-forming potentials, antimicrobial resistance, and genes in S. aureus isolates. Methods: A total of 64 milk samples were analysed, and 77 S. aureus were isolated. Results: Seventy (90.9%) isolates were biofilm producers. The ica biofilm-forming genes were detected among 75.3% of the isolates, with icaA being the most prevalent (49, 63.6%). The icaB gene was significantly (P = 0.027) higher in isolates with strong biofilm formation potentials. High resistance (60%-90%) of the isolates was observed against ceftriaxone, vancomycin, and penicillin, and 25 (32.5%) of S. aureus showed multidrug resistance (MDR) to at least three antibiotics. Five resistance genes, namely blaZ (29, 37.7%), vanC (29, 37.7%), tetK (24, 31.2%), tetL (21, 27.3%), and msrA/B (16, 20.8%) were detected. Most MDR phenotypes possessed at least one resistance gene alongside the biofilm genes. However, no distinct pattern was identified among the resistance and biofilm phenotypes. Conclusions: The high frequency of potentially pathogenic MDR S. aureus in milk samples intended for human consumption, demonstrates the public health relevance of this pathogen in the region.}, } @article {pmid32251913, year = {2020}, author = {Feng, X and Wu, Q and Che, L and Ren, N}, title = {Analyzing the inhibitory effect of metabolic uncoupler on bacterial initial attachment and biofilm development and the underlying mechanism.}, journal = {Environmental research}, volume = {185}, number = {}, pages = {109390}, doi = {10.1016/j.envres.2020.109390}, pmid = {32251913}, issn = {1096-0953}, mesh = {Biofilms ; *Biofouling ; Bioreactors ; *Extracellular Polymeric Substance Matrix ; Sewage ; }, abstract = {Metabolic uncouplers inhibit biofilm and biofouling formation in membrane bioreactor (MBR) systems, which have been considered as a potential biofouling control alternative. To better understand the inhibitory mechanism of uncoupler on biofouling, this study investigated the impact of the uncoupler 3, 3', 4', 5-tetrachlorosalicylanilide (TCS) on biofilm formation of B. subtilis in different development stages. Significant reductions in both the initial bacterial attachment stage and the subsequent biofilm development stage were caused by TCS at 100 μg/L. The motility of B. subtilis in semisolid medium was inhibited by TCS, which explicitly explained the reduction in initial bacterial attachment. Meanwhile, a reduction of extracellular polymeric substance (EPS) secretion owing to TCS suggested why biofilm development was suppressed. In addition, the fluorescent materials in tight-bound EPS (TB-EPS) and loose-bound EPS (LB-EPS) of Bacillus subtilis cultured in different TCS concentrations were distinguished and quantified by three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). The results of this study suggested that the biofilm inhibitory mechanism of the uncoupler was both a inhibition in bacterial motor ability and a reduction in EPS secretion.}, } @article {pmid32251912, year = {2020}, author = {Wang, J and Li, G and Yin, H and An, T}, title = {Bacterial response mechanism during biofilm growth on different metal material substrates: EPS characteristics, oxidative stress and molecular regulatory network analysis.}, journal = {Environmental research}, volume = {185}, number = {}, pages = {109451}, doi = {10.1016/j.envres.2020.109451}, pmid = {32251912}, issn = {1096-0953}, mesh = {Bacteria ; *Biofilms ; Copper/toxicity ; *Extracellular Polymeric Substance Matrix ; Oxidative Stress ; }, abstract = {Overwhelming growth of bacterial biofilms on different metal-based pipeline materials are intractable and pose a serious threat to public health when tap water flows though these pipelines. Indeed, the underlying mechanism of biofilm growth on the surface of different pipeline materials deserves detailed exploration to provide subsequent implementation strategies for biofilm control. Thus, in this study, how bacteria response to their encounters was explored, when they inhabit different metal-based pipeline substrates. Results revealed that bacteria proliferated when they grew on stainless steel (SS) and titanium sheet (Ti), quickly developing into bacterial biofilms. In contrast, the abundance of bacteria on copper (Cu) and nickel foam (Ni) substates decreased sharply by 4-5 logs within 24 h. The morphological shrinkage and shortening of bacterial cells, as well as a sudden 64-fold increase of carbohydrate content in extracellular polymeric substances (EPS), were observed on Cu substrate. Furthermore, generation of reactive oxygen species and fluctuation of enzymatic activity demonstrated the destruction of redox equilibrium in bacteria. Bacteria cultured on Cu substrate showed the strongest response, followed by Ni, SS and Ti. The oxidative stress increased quickly during the growth of bacterial biofilm, and almost all tested metal transporter-related genes were upregulated by 2-11 folds on Cu, which were higher than on other substrates (1-2 folds for SS and Ti, 2-9 folds for Ni). Finally, these behaviors were compared under the biofilm regulatory molecular network. This work may facilitate better understanding different response mechanisms during bacterial biofilm colonization on metal-based pipelines and provide implications for subsequent biofilm control.}, } @article {pmid32250587, year = {2020}, author = {Lee, JH and Kim, YG and Khadke, SK and Yamano, A and Watanabe, A and Lee, J}, title = {Correction to Inhibition of Biofilm Formation by Candida albicans and Polymicrobial Microorganisms by Nepodin via Hyphal-Growth Suppression.}, journal = {ACS infectious diseases}, volume = {6}, number = {5}, pages = {1283}, doi = {10.1021/acsinfecdis.0c00146}, pmid = {32250587}, issn = {2373-8227}, } @article {pmid32249239, year = {2020}, author = {Tsuchiya, Y and Nakagawa, T and Takahashi, R}, title = {Quantification and Phylogenetic Analysis of Ammonia Oxidizers on Biofilm Carriers in a Full-Scale Wastewater Treatment Plant.}, journal = {Microbes and environments}, volume = {35}, number = {2}, pages = {}, pmid = {32249239}, issn = {1347-4405}, mesh = {Ammonia/*metabolism ; Archaea/*classification/metabolism ; Bacteria/*classification/metabolism ; Biofilms/*growth & development ; Japan ; Nitrification ; Oxidation-Reduction ; Phylogeny ; *Waste Disposal, Fluid ; Wastewater/*microbiology ; }, abstract = {Biofilm carriers have been used to remove ammonia in several wastewater treatment plants (WWTPs) in Japan. However, the abundance and species of ammonia oxidizers in the biofilms formed on the surface of carriers in full-scale operational WWTP tanks remain unclear. In the present study, we conducted quantitative PCR and PCR cloning of the amoA genes of ammonia-oxidizing bacteria and archaea (AOB and AOA) and a complete ammonia oxidizer (comammox) in the biofilm formed on the carriers in a full-scale WWTP. The quantification of amoA genes showed that the abundance of AOB and comammox was markedly greater in the biofilm than in the activated sludge suspended in a tank solution of the WWTP, while AOA was not detected in the biofilm or the activated sludge. A phylogenetic analysis of amoA genes revealed that as-yet-uncultivated comammox Nitrospira and uncultured AOB Nitrosomonas were predominant in the biofilm. The present results suggest that the biofilm formed on the surface of carriers enable comammox Nitrospira and AOB Nitrosomonas to co-exist and remain in the full-scale WWTP tank surveyed in this study.}, } @article {pmid32249162, year = {2020}, author = {Kishii, K and Hamada, M and Aoki, K and Ito, K and Onodera, J and Ishii, Y and Tateda, K}, title = {Differences in biofilm formation and transcription of biofilm-associated genes among Acinetobacter baumannii clinical strains belonging to the international clone II lineage.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {26}, number = {7}, pages = {693-698}, doi = {10.1016/j.jiac.2020.02.017}, pmid = {32249162}, issn = {1437-7780}, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/genetics/*pathogenicity ; Biofilms/*growth & development ; DNA, Bacterial/genetics/isolation & purification ; Fimbriae Proteins/genetics ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Humans ; Operon/genetics ; *Transcription, Genetic ; Virulence/genetics ; Whole Genome Sequencing ; }, abstract = {Acinetobacter baumannii isolates belonging to international clonal lineage (IC) II are often multidrug-resistant and are the predominant cause of nosocomial outbreaks. While many studies have investigated the genetic and functional basis of antimicrobial resistance of these strains, few have examined specific virulence characteristics such as biofilm formation or overall pathogenic potential. Here, we analyzed biofilm formation and the associated mechanisms in A. baumannii clinical isolates from Japan belonging to the IC II lineage. Draft whole-genome sequence data for each of the isolates was analyzed to detect biofilm-associated genes, including csu (pili) and bfmS/R (two-component regulatory system), and transcription of these genes was evaluated using reverse transcription quantitative PCR. Biofilm formation was measured by crystal violet staining assay. csu operon genes showed some variation in prevalence among the isolates, with an overall prevalence of 73.7% (14/19). The biofilms formed by csu operon-positive isolates were significantly more mature than those of csu operon-negative isolates, supporting the importance of the csu operon in biofilm formation by A. baumannii. However, there was substantial variation among the csu operon-positive isolates, indicating the influence of other factors in biofilm formation. Furthermore, transcriptional levels of csu operon genes were highly divergent, with comprehensive analysis indicating that regulatory factors other than bfmS/R were involved. Our findings are a first step towards understanding the mechanisms of biofilm formation by A. baumannii IC II strains.}, } @article {pmid32248441, year = {2020}, author = {Duc, HM and Son, HM and Ngan, PH and Sato, J and Masuda, Y and Honjoh, KI and Miyamoto, T}, title = {Isolation and application of bacteriophages alone or in combination with nisin against planktonic and biofilm cells of Staphylococcus aureus.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {11}, pages = {5145-5158}, doi = {10.1007/s00253-020-10581-4}, pmid = {32248441}, issn = {1432-0614}, mesh = {Animals ; Biofilms/drug effects/growth & development ; Chickens/virology ; Fishes/virology ; Food Microbiology/*methods ; Genome, Viral ; Host Specificity ; Nisin/pharmacology ; Podoviridae/genetics/isolation & purification/*metabolism ; Pork Meat/virology ; Staphylococcus Phages/genetics/*isolation & purification/*metabolism ; Staphylococcus aureus/*drug effects/growth & development/virology ; Virulence/drug effects ; }, abstract = {Staphylococcus aureus is a notorious foodborne pathogen since it has ability to produce variety of toxins including heat-stable enterotoxin, form biofilm, and acquire resistance to antibiotics. Biocontrol of foodborne pathogens by lytic bacteriophages garners increasing interest from both researchers and food industry. In the present study, 29 phages against S. aureus were successfully isolated from chicken, pork, and fish. Characterization of the isolates revealed that phage SA46-CTH2 belonging to Podoviridae family had a number of features suitable for food industry applications such as wide host range, short latent period, large burst size, high stress tolerance, and a genome free of virulence genes. Furthermore, phage SA46-CTH2 alone or in combination with nisin exhibited great efficacy in reducing planktonic and biofilm cells of S. aureus at various conditions tested. The combination of phage SA46-CTH2 and nisin was also found to be able to inhibit the regrowth of S. aureus at both 37 and 24 °C.Key points• A total of 29 S. aureus phages were successfully isolated from fish, pork, and chicken products. • Phage SA46-CTH2 was characterized by host range, morphology, and genome sequencing. • SA46-CTH2 significantly reduced both planktonic and biofilm cells of S. aureus. • Combination of SA46-CTH2 and nisin inhibited the regrowth of S. aureus.}, } @article {pmid32248439, year = {2020}, author = {Shu, Q and Wei, T and Lu, H and Niu, Y and Chen, Q}, title = {Mannosylerythritol lipids: dual inhibitory modes against Staphylococcus aureus through membrane-mediated apoptosis and biofilm disruption.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {11}, pages = {5053-5064}, doi = {10.1007/s00253-020-10561-8}, pmid = {32248439}, issn = {1432-0614}, support = {LR13C200002//Natural Science Foundation of Zhejiang Province/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Apoptosis/*drug effects ; Bacterial Outer Membrane/*drug effects ; Biofilms/*drug effects/growth & development ; Food Microbiology ; Glycolipids/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Staphylococcus aureus/*drug effects ; Surface-Active Agents/pharmacology ; }, abstract = {Mannosylerythritol lipids (MELs) are novel biosurfactants performing excellent physical-chemical properties as well as bioactivities. This study is aimed to explore the antibacterial and antibiofilm activity of mannosylerythritol lipids against foodborne gram-positive Staphylococcus aureus. The results of growth curve and survival rate revealed the significant inhibitory effect of MELs against S. aureus. The visualized pictures by scanning electron microscope and transmission electron microscope exposed apparent morphological and ultrastructure changes of MEL-treated cells. Furthermore, flow cytometry confirmed that MELs have promoted cell apoptosis and damaged the cell membrane. Notably, MEL-A also exhibited outstanding antibiofilm activity against S. aureus biofilm on different material surfaces including polystyrene, glass, and stainless steel, verified by confocal laser scanning microscope. These findings suggest that the antimicrobial activity of MELs is related to inhibit planktonic cells and biofilm of S. aureus, indicating that it has potential to be an alternative to antibacterial agents and preservatives applied into food processing.Key Points • MELs have strong antibacterial activity against Staphylococcus aureus.• MELs mainly damage the cell membrane of Staphylococcus aureus.• Mannosylerythritol lipids inhibit the bacterial adhesion to remove biofilm.}, } @article {pmid32246698, year = {2020}, author = {Narayanan, VS and Muddaiah, S and Shashidara, R and Sudheendra, US and Deepthi, NC and Samaranayake, L}, title = {Variable antifungal activity of curcumin against planktonic and biofilm phase of different candida species.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {31}, number = {1}, pages = {145-148}, doi = {10.4103/ijdr.IJDR_521_17}, pmid = {32246698}, issn = {1998-3603}, mesh = {Antifungal Agents ; Biofilms ; *Candida ; Candida albicans ; *Curcumin ; Fluconazole ; Microbial Sensitivity Tests ; Plankton ; }, abstract = {OBJECTIVE: To evaluate the in vitro antifungal activity of curcumin against 2 strains of Candida albicans (ATCC 90028 and a clinical isolate - JY strain) and 1 isolate each of 3 nonalbicans - Candida species [Candida parapsilosis (ATCC 22019), C. glabrata (ATCC 90030), and C. dublieniensis (MYA 646)].

MATERIALS AND METHODS: Planktonic MIC of the 4 Candida species was determined using micro broth dilution assay according to CLSI M27-A3 criteria. The biofilm development and sensitivity assay were performed with the 2 C. albicans strains.

RESULTS: Curcumin at high concentrations (0.1-2 mg/mL) was effective in inhibiting planktonic organisms of all the 5 tested Candida strains. The planktonic phase and the biofilm phase of C. albicans ATCC 90028 exhibited similar MIC values for curcumin (0.5 mg/mL). Both curcumin and fluconazole were ineffective against the mature biofilms of JY strain.

CONCLUSION: Our results reported here for the first time, in particular for the biofilm state of C. albicans, imply that curcumin a natural product could be used as a therapeutic alternative to conventional antifungals although further investigations are required to evaluate its potential.}, } @article {pmid32245764, year = {2020}, author = {Romero, F and Acuña, V and Sabater, S}, title = {Multiple Stressors Determine Community Structure and Estimated Function of River Biofilm Bacteria.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {12}, pages = {}, pmid = {32245764}, issn = {1098-5336}, mesh = {Bacteria/classification/genetics ; *Bacterial Physiological Phenomena ; *Biofilms ; *Climate Change ; Desiccation ; Hot Temperature/adverse effects ; Microbiota/*physiology ; Pesticides/adverse effects ; RNA, Bacterial/analysis ; RNA, Ribosomal, 16S/analysis ; Rivers/*microbiology ; Stress, Physiological ; Water Pollutants, Chemical/adverse effects ; }, abstract = {Freshwater ecosystems are exposed to multiple stressors, but their individual and combined effects remain largely unexplored. Here, we investigated the response of stream biofilm bacterial communities to warming, hydrological stress, and pesticide exposure. We used 24 artificial streams on which epilithic (growing on coarse sediments) and epipsammic (growing on fine sediments) stream biofilms were maintained. Bacterial community composition and estimated function of biofilms exposed during 30 days to individual and combined stressors were assessed using 16S rRNA gene metabarcoding. Among the individual effects by stressors, hydrological stress (i.e., a simulated low-flow situation) was the most relevant, since it significantly altered 57% of the most abundant bacterial taxa (n = 28), followed by warming (21%) and pesticide exposure (11%). Regarding the combined effects, 16% of all stressor combinations resulted in significant interactions on bacterial community composition and estimated function. Antagonistic responses prevailed (57 to 89% of all significant interactions), followed by synergisms (11 to 43%), on specific bacterial taxa, indicating that multiple-stressor scenarios could lead to unexpected shifts in the community composition and associated functions of riverine bacterial communities.IMPORTANCE Freshwater ecosystems such as rivers are of crucial importance for human well-being. However, human activities result in many stressors (e.g., toxic chemicals, increased water temperatures, and hydrological alterations) cooccurring in rivers and streams worldwide. Among the many organisms inhabiting rivers and streams, bacteria are ecologically crucial; they are placed at the base of virtually all food webs and they recycle the organic matter needed for bigger organisms. Most of these bacteria are in close contact with river substratum, where they form the biofilms. There is an urgent need to evaluate the effects of these stressors on river biofilms, so we can anticipate future environmental problems. In this study, we experimentally exposed river biofilms to a pesticide mixture, an increase in water temperature and a simulated low-flow condition, in order to evaluate the individual and joint effects of these stressors on the bacterial community composition and estimated function.}, } @article {pmid32244101, year = {2020}, author = {Wen, HQ and Ren, HY and Xie, GJ and Cao, GL and Xing, DF and Ren, NQ and Liu, BF}, title = {Synthesized effects of proteomic and extracellular polymeric substance (EPS) revealing the enhanced hydrogen production by formed biofilm of photo-fermentative bacteria.}, journal = {Environment international}, volume = {139}, number = {}, pages = {105683}, doi = {10.1016/j.envint.2020.105683}, pmid = {32244101}, issn = {1873-6750}, mesh = {Bacteria ; Biofilms ; *Extracellular Polymeric Substance Matrix ; Hydrogen ; *Proteomics ; }, abstract = {Photo-fermentative hydrogen production, the new energy production alternative, was greatly enhanced by formed biofilm. To understand the mechanism of enhancement, the intracellular proteome and extracellular polymeric substance (EPS)[i] during biofilm formation were investigated in this work. Experimental results indicated that a possible and effective altered system could transfer light to hydrogen. Proteins were significantly regulated, for example those related with nitrogenase, flagellin, EPS transportation and DNA duplication were up-regulated while those concerned photosystem were down-regulated. It revealed these changes of proteins contributed to positive activity of key enzymes, improved communication system and increased total light utilization efficiency thus leading to enhanced capacity of hydrogen production. Besides above metabolic changes inside the cells, EPS secreted by the bacteria played an important role in hydrogen production and its yield decided the release of hydrogen. When EPS descended to a lower concentration during biofilm formation, it meant carbon source for EPS synthesis was reduced, and more energy and reducing power could be transferred into hydrogen energy. More importantly, this work found that composition and structure of EPS were efficiently influenced by the formation of biofilm, such as benzene and O-H structure, secondary protein structure and the kinds of protein, which were important to stable biofilm and efficient hydrogen production. Therefore, final hydrogen yield was improved by altered protein and EPS resulted from biofilm formation. This study demonstrated that formation of biofilm is an efficient, ecological and attracting way to the future bio-hydrogen production.}, } @article {pmid32243047, year = {2020}, author = {Ho, DK and Murgia, X and De Rossi, C and Christmann, R and Hüfner de Mello Martins, AG and Koch, M and Andreas, A and Herrmann, J and Müller, R and Empting, M and Hartmann, RW and Desmaele, D and Loretz, B and Couvreur, P and Lehr, CM}, title = {Squalenyl Hydrogen Sulfate Nanoparticles for Simultaneous Delivery of Tobramycin and an Alkylquinolone Quorum Sensing Inhibitor Enable the Eradication of P. aeruginosa Biofilm Infections.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {59}, number = {26}, pages = {10292-10296}, pmid = {32243047}, issn = {1521-3773}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Delayed-Action Preparations/chemistry/toxicity ; Drug Synergism ; Humans ; Microbial Sensitivity Tests ; Mucus/microbiology ; Nanoparticles/*chemistry/toxicity ; Pseudomonas aeruginosa/*drug effects/physiology ; Quinolones/pharmacology ; Quorum Sensing/*drug effects ; Squalene/analogs & derivatives/toxicity ; Sulfuric Acid Esters/chemistry/toxicity ; Tobramycin/*pharmacology ; Zebrafish ; }, abstract = {Elimination of pulmonary Pseudomonas aeruginosa (PA) infections is challenging to accomplish with antibiotic therapies, mainly due to resistance mechanisms. Quorum sensing inhibitors (QSIs) interfering with biofilm formation can thus complement antibiotics. For simultaneous and improved delivery of both active agents to the infection sites, self-assembling nanoparticles of a newly synthesized squalenyl hydrogen sulfate (SqNPs) were prepared. These nanocarriers allowed for remarkably high loading capacities of hydrophilic antibiotic tobramycin (Tob) and a novel lipophilic QSI at 30 % and circa 10 %, respectively. The drug-loaded SqNPs showed improved biofilm penetration and enhanced efficacy in relevant biological barriers (mucin/human tracheal mucus, biofilm), leading to complete eradication of PA biofilms at circa 16-fold lower Tob concentration than Tob alone. This study offers a viable therapy optimization and invigorates the research and development of QSIs for clinical use.}, } @article {pmid32242775, year = {2021}, author = {García-Borjas, KA and Ceballos-Olvera, I and Luna-Castro, S and Peña-Avelino, Y}, title = {Bovine Lactoferrin can Decrease the In Vitro Biofilm Production and Show Synergy with Antibiotics Against Listeria and Escherichia coli Isolates.}, journal = {Protein and peptide letters}, volume = {28}, number = {1}, pages = {101-107}, doi = {10.2174/0929866527666200403111743}, pmid = {32242775}, issn = {1875-5305}, support = {DSA/103.5/16/10526//PRODEP Mexico/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cattle ; Drug Synergism ; Escherichia coli/isolation & purification/*physiology ; Lactoferrin/agonists/*pharmacology ; Listeria/isolation & purification/*physiology ; }, abstract = {BACKGROUND: Bovine Lactoferrin (bLf) has been reported as antimicrobial, antiviral, immunomodulatory and anticancer protein. Escherichia coli and Listeria spp. are food-borne bacteria that can produce illness in human being and mammals, the emergent antimicrobial drug resistance has been reported in these pathogens.

OBJECTIVE: The aim for this study was to evaluate the bLf effect on in vitro biofilm production and the synergic effect of antibiotics on E. coli and Listeria isolates.

METHODS: E. coli and Listeria specimens were isolated from bovine carcasses and slaughterhouses surfaces, respectively. Biofilm formation was analyzed with or without bLf, incubated for 48 h and spectrophotometry, cell viability was analyzed by colony-forming unit (CFU) and the synergistic effect of bLf with ampicillin, oxytetracycline, and streptomycin was evaluated through the fractional concentration index (FCI).

RESULTS: Our results show that a low bLf concentration (0.8 μM) can diminish the in vitro biofilm production in Listeria isolates; also improves the in vitro oxytetracycline and streptomycin activity against E. coli, and ampicillin activity against Listeria isolates.

CONCLUSION: bLf can affect the biofilm production in Listeria isolates from slaughterhouses surfaces and shown synergic effect with ampicillin. Also has a synergic effect with oxytetracycline and streptomycin against E. coli isolates from bovine carcasses.}, } @article {pmid32242746, year = {2020}, author = {Robino, L and Scavone, P}, title = {Nanotechnology in biofilm prevention.}, journal = {Future microbiology}, volume = {15}, number = {}, pages = {377-379}, doi = {10.2217/fmb-2019-0327}, pmid = {32242746}, issn = {1746-0921}, mesh = {Bacterial Infections/*prevention & control/*therapy ; *Biofilms/growth & development ; Disinfection/methods ; Equipment and Supplies ; Humans ; *Nanostructures ; *Nanotechnology ; }, } @article {pmid32242627, year = {2020}, author = {Angiolella, L and Rojas, F and Mussin, J and Greco, R and Sosa, MLA and Zalazar, L and Giusiano, G}, title = {Biofilm formation, adherence, and hydrophobicity of M. sympodialis, M. globosa, and M. slooffiae from clinical isolates and normal skinVirulence factors of M. sympodialis, M. globosa and M. slooffiae.}, journal = {Medical mycology}, volume = {58}, number = {8}, pages = {1162-1168}, doi = {10.1093/mmy/myaa017}, pmid = {32242627}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Cell Adhesion ; Dermatomycoses/*microbiology ; Humans ; Hydrophobic and Hydrophilic Interactions ; Malassezia/classification/isolation & purification/*physiology ; Skin/*microbiology ; Species Specificity ; Virulence Factors ; }, abstract = {The genus Malassezia comprises a heterogeneous group of species that cause similar pathologies. Malassezia yeasts were considered as the most abundant skin eukaryotes of the total skin mycobiome. The ability of this fungus to colonize or infect is determined by complex interactions between the fungal cell and its virulence factors. This study aims to evaluate in vitro the hydrophobicity levels, the adherence capacity on a polystyrene surface and the ability to form biofilm of 19 isolates, including M. sympodialis, M. globosa, and M. slooffiae, from healthy subjects and from dermatological disorders. Cellular surface hydrophobicity levels were determined by two-phase system. The biofilm formation was determined by tetrazolium salt (XTT) reduction assay and by Scanning Electron Microscopy (SEM). Strain dependence was observed in all virulence factors studied. All isolates of M. sympodialis, M. globosa, and M. slooffiae demonstrated their ability to form biofilm at variable capacities. SEM observations confirmed a variable extracellular matrix after 48 hours of biofilm formation. All isolates of M. globosa were highly adherent and/or hydrophobic as well as biofilm producers. In contrast, M. slooffiae was the least biofilm producer. No significant differences between virulence factors were demonstrated for M. sympodialis, either as clinical isolate or as inhabitant of human microbiota. Results of this work together with the previous M. furfur research confirm that the most frequently Malassezia species isolated from normal subject's skin and patients with dermatosis, form biofilm with different capacities. The study of these virulence factors is important to highlight differences between Malassezia species and to determine their involvement in pathological processes.}, } @article {pmid32242577, year = {2020}, author = {Zhang, L and Li, Z and Chen, Z}, title = {Live cell fluorescent stain of bacterial curli and biofilm through supramolecular recognition between bromophenol blue and CsgA.}, journal = {Chemical communications (Cambridge, England)}, volume = {56}, number = {37}, pages = {5014-5017}, doi = {10.1039/d0cc01643h}, pmid = {32242577}, issn = {1364-548X}, mesh = {Bacterial Proteins/*chemistry/metabolism ; *Biofilms ; Bromphenol Blue/*chemistry ; Escherichia coli/physiology ; Escherichia coli Proteins/*chemistry/genetics/metabolism ; Microscopy, Fluorescence ; Protein Binding ; Recombinant Proteins/biosynthesis/chemistry/isolation & purification ; Spectrometry, Fluorescence ; }, abstract = {Identification of curli-specific dyes for biofilm communities of microorganisms is an important task. We describe here a curli fluorescent light-up probe called bromophenol blue, which binds to curli via recognizing CsgA. This platform may provide a new perspective for the research on biofilm, amyloid disease and living materials.}, } @article {pmid32241895, year = {2020}, author = {Starr, CG and Ghimire, J and Guha, S and Hoffmann, JP and Wang, Y and Sun, L and Landreneau, BN and Kolansky, ZD and Kilanowski-Doroh, IM and Sammarco, MC and Morici, LA and Wimley, WC}, title = {Synthetic molecular evolution of host cell-compatible, antimicrobial peptides effective against drug-resistant, biofilm-forming bacteria.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {15}, pages = {8437-8448}, pmid = {32241895}, issn = {1091-6490}, support = {R21 AI119104/AI/NIAID NIH HHS/United States ; U54 GM104940/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/*chemical synthesis/chemistry ; Antimicrobial Cationic Peptides/*administration & dosage/*chemical synthesis/chemistry ; Bacteria/*drug effects/genetics ; Bacterial Infections/*drug therapy/microbiology ; Biofilms/*drug effects ; Directed Molecular Evolution ; *Drug Resistance, Bacterial ; Female ; Humans ; Mice ; Microbial Sensitivity Tests ; }, abstract = {Novel classes of antibiotics and new strategies to prevent and treat infections are urgently needed because the rapid rise in drug-resistant bacterial infections in recent decades has been accompanied by a parallel decline in development of new antibiotics. Membrane permeabilizing antimicrobial peptides (AMPs) have long been considered a potentially promising, novel class of antibiotic, especially for wound protection and treatment to prevent the development of serious infections. Yet, despite thousands of known examples, AMPs have only infrequently proceeded as far as clinical trials, especially the chemically simple, linear examples. In part, this is due to impediments that often limit their applications in vivo. These can include low solubility, residual toxicity, susceptibility to proteolysis, and loss of activity due to host cell, tissue, and protein binding. Here we show how synthetic molecular evolution can be used to evolve potentially advantageous antimicrobial peptides that lack these impediments from parent peptides that have at least some of them. As an example of how the antibiotic discovery pipeline can be populated with more promising candidates, we evolved and optimized one family of linear AMPs into a new generation with high solubility, low cytotoxicity, potent broad-spectrum sterilizing activity against a panel of gram-positive and gram-negative ESKAPE pathogens, and antibiofilm activity against gram-positive and gram-negative biofilms. The evolved peptides have these activities in vitro even in the presence of concentrated host cells and also in vivo in the complex, cell- and protein-rich environment of a purulent animal wound model infected with drug-resistant bacteria.}, } @article {pmid32240676, year = {2020}, author = {Ayoub, HM and Gregory, RL and Tang, Q and Lippert, F}, title = {Comparison of human and bovine enamel in a microbial caries model at different biofilm maturations.}, journal = {Journal of dentistry}, volume = {96}, number = {}, pages = {103328}, doi = {10.1016/j.jdent.2020.103328}, pmid = {32240676}, issn = {1879-176X}, mesh = {Animals ; Biofilms ; Cariostatic Agents/therapeutic use ; Cattle ; *Dental Caries/drug therapy ; Dental Enamel ; Fluorides ; Humans ; Hydrogen-Ion Concentration ; *Tooth Demineralization ; }, abstract = {OBJECTIVES: To compare human versus bovine enamel when used in microbial caries models; and to evaluate the use of nylon mesh to support biofilm growth over enamel.

METHODS: Twenty-four sub-subgroups were included (time factor: 4, 8, and 12 days; substrate factor: human/bovine; mesh factor: yes/no; treatment factor: 18.4 mM NaF (350 ppm F), de-ionized water [DIW]; n = 9/sub-subgroup). Microcosm biofilm from human saliva (IRB approval #1,406,440,799) was grown on enamel specimens for 24-h (Brain Heart Infusion media; 0.2 % sucrose), using active attachment model. Then, pH-cycling took place. At the end of each pH-cycling period, enamel specimens were analyzed: surface microhardness (VHNchange); transverse microradiography (integrated mineral loss [ΔZ], lesion depth [L]). Biofilm was analyzed: lactic acid production (LDH activity); exopolysaccharide (EPS) amount; and viability (12-day sub-groups). Data were analyzed using ANOVA at a 5 % level of significance.

RESULTS: The three-way interaction between pH-cycling duration, substrate type, and treatment type was significant for (VHNchange [p < 0.0005], ΔZ [p = 0.0027], and L [p < 0.0001]). VHNchange exhibited increased lesion severity as pH-cycling time increases, in both treatments. VHNchange data indicated a treatment effect in all timepoints. ΔZ and L exhibited higher values with more mature biofilms. ANOVA analyses for LDH and EPS indicated a significance between variables (LDH p = 0.0100; EPS p < 0.0001). Mesh-covered specimens resulted in lower LDH and EPS values in all maturations. ANOVA analyses of viability (12 days) between variables was significant.

CONCLUSION: within the study's limitations, human or bovine enamel can be used in microbial in vitro caries models to study biofilm's maturation and anticaries agents.

CLINICAL SIGNIFICANCE: This study demonstrated how a known cariostatic effect of a fluoride concentration in toothpastes can be modulated by the maturation stage of oral biofilm. This can represent hard to reach areas in the oral cavity (e.g. in orthodontic patients or patients with intermaxillary fixation following oral and maxillofacial surgeries).}, } @article {pmid32239203, year = {2020}, author = {Ageorges, V and Monteiro, R and Leroy, S and Burgess, CM and Pizza, M and Chaucheyras-Durand, F and Desvaux, M}, title = {Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation.}, journal = {FEMS microbiology reviews}, volume = {44}, number = {3}, pages = {314-350}, doi = {10.1093/femsre/fuaa008}, pmid = {32239203}, issn = {1574-6976}, mesh = {Bacterial Adhesion/genetics ; *Biofilms ; Diarrhea/etiology/microbiology ; Escherichia coli/*genetics ; Escherichia coli Infections/complications/microbiology ; Genes, Bacterial/genetics ; }, abstract = {Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.}, } @article {pmid32238987, year = {2020}, author = {Macedo, VC and Pereira, PC and Queiroz, JRC and Dal Piva, AMO and Moura, DMD and Tango, RN and Bottino, MA and Souza, ROAE}, title = {Effect of Air-Particle-Abrasion Protocols on Surface Roughness and Early Biofilm Formation of Zirconia.}, journal = {Oral health & preventive dentistry}, volume = {18}, number = {1}, pages = {153-159}, doi = {10.3290/j.ohpd.a44321}, pmid = {32238987}, issn = {1757-9996}, mesh = {Biofilms ; *Dental Bonding ; Dental Materials ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; *Silicon Dioxide ; Surface Properties ; Zirconium ; }, abstract = {PURPOSE: The air-particle-abrasion on zirconia in the gingival area of connectors and pontics in fixed partial dentures appears to increase fracture resistance. This study evaluated 'in situ' biofilm formation on the zirconia surface after different air-particle-abrasion protocols.

MATERIALS AND METHODS: Ninety sintered blocks (5 × 5 × 2 mm) of yttrium partially stabilised zirconia (Y-TZP) were obtained and randomised among nine groups according to the factors 'type of particle' (Alumina 50 and 110 µm; Cojet and Rocatec) and 'pressure' (2.5 and 3.5 bar) used for sandblasting for 10 s. The surface roughness (Ra/Rz) was measured before and after sandblasting. For the in-situ analyses, custom-made removable intraoral devices n = 10 with one sample of each group attached to the buccal area were used by volunteers for 8 h at night. The specimens were analysed under confocal microscopy to quantify both biovolume and thickness of the initial biofilm formed. One-way analysis of variance (ANOVA) and Dunnett's tests were performed (5%).

RESULTS: The roughness values ranged from 0.05 to 0.39 µm for Ra and from 0.35 to 2.11 µm for Rz, p = 0.00. Mean biofilm thickness ranged from 0.06 and 0.54 µm (p = 0.005), while the biovolume values were between 0.02 and 0.61 µm3/µm2 (p = 0.002). Values statistically significant for biofilm thickness and biovolume were found in groups sandblasted with Rocatec using 3.5 bar.

CONCLUSION: In order to increase the fracture resistance of zirconia fixed partial dentures (FPDs), the air particle abrasion of zirconia with SiO2 (110 μm/3.5 bar), in the gingival area of connectors and pontics, should be avoided.}, } @article {pmid32238858, year = {2020}, author = {Galdiero, E and de Alteriis, E and De Natale, A and D'Alterio, A and Siciliano, A and Guida, M and Lombardi, L and Falanga, A and Galdiero, S}, title = {Eradication of Candida albicans persister cell biofilm by the membranotropic peptide gH625.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {5780}, pmid = {32238858}, issn = {2045-2322}, mesh = {Amino Acid Sequence ; Amphotericin B/pharmacology ; Antifungal Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Candidiasis/drug therapy/microbiology ; Drug Design ; Drug Resistance, Fungal/drug effects ; Humans ; }, abstract = {Biofilm formation poses an important clinical trouble due to resistance to antimicrobial agents; therefore, there is an urgent demand for new antibiofilm strategies that focus on the use of alternative compounds also in combination with conventional drugs. Drug-tolerant persisters are present in Candida albicans biofilms and are detected following treatment with high doses of amphotericin B. In this study, persisters were found in biofilms treated with amphotericin B of two clinical isolate strains, and were capable to form a new biofilm in situ. We investigated the possibility of eradicating persister-derived biofilms from these two Candida albicans strains, using the peptide gH625 analogue (gH625-M). Confocal microscopy studies allowed us to characterize the persister-derived biofilm and understand the mechanism of interaction of gH625-M with the biofilm. These findings confirm that persisters may be responsible for Candida biofilm survival, and prove that gH625-M was very effective in eradicating persister-derived biofilms both alone and in combination with conventional antifungals, mainly strengthening the antibiofilm activity of fluconazole and 5-flucytosine. Our strategy advances our insights into the development of effective antibiofilm therapeutic approaches.}, } @article {pmid32238809, year = {2020}, author = {Gierl, L and Stoy, K and Faíña, A and Horn, H and Wagner, M}, title = {An open-source robotic platform that enables automated monitoring of replicate biofilm cultivations using optical coherence tomography.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {18}, pmid = {32238809}, issn = {2055-5008}, mesh = {Bacteriological Techniques/methods ; Biofilms/*growth & development ; Robotics ; Tomography, Optical Coherence/*instrumentation ; User-Computer Interface ; }, abstract = {The paper introduces a fully automated cultivation and monitoring tool to study biofilm development in replicate experiments operated in parallel. To gain a fundamental understanding of the relation between cultivation conditions and biofilm characteristics (e.g., structural, mechanical) a monitoring setup allowing for the standardization of methods is required. Optical coherence tomography (OCT) is an imaging modality ideal for biofilms since it allows for the monitoring of structure in real time. By integrating an OCT device into the open-source robotic platform EvoBot, a fully automated monitoring platform for investigating biofilm development in several flow cells at once was realized. Different positioning scenarios were tested and revealed that the positioning accuracy is within the optical resolution of the OCT. On that account, a reliable and accurate monitoring of biofilm development by means of OCT has become possible. With this robotic platform, reproducible biofilm experiments including a statistical analysis are achievable with only a small investment of operator time. Furthermore, a number of structural parameters calculated within this study confirmed the necessity to perform replicate biofilm cultivations.}, } @article {pmid32238271, year = {2020}, author = {Ionescu, AC and Hahnel, S and König, A and Brambilla, E}, title = {Resin composite blocks for dental CAD/CAM applications reduce biofilm formation in vitro.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {5}, pages = {603-616}, doi = {10.1016/j.dental.2020.03.016}, pmid = {32238271}, issn = {1879-0097}, mesh = {Biofilms ; *Composite Resins ; Computer-Aided Design ; *Dental Materials ; Humans ; Materials Testing ; Surface Properties ; }, abstract = {OBJECTIVES: Modern dentistry is increasingly focusing on digital procedures, including CAD/CAM technologies. New materials have to resist in a demanding environment that includes secondary caries occurrence. The current study hypothesized that the microbiological behavior of different RBCs for CAD/CAM applications is better than that of their counterparts for direct restorations due to differences in the surface characteristics.

METHODS: Both direct and CAD/CAM RBCs were tested. Specimens were obtained from each group, polished, cleaned, stored in artificial saliva (1w), then sterilized under UV (24h). Specimens' surface was assessed using profilometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction; resin/filler content was assessed using thermogravimetry. After pre-incubation with sterile human saliva (24h), the microbiological behavior of the materials was assessed using four models: Streptococcus mutans adherence (2h), S. mutans biofilm formation in an orbital shaking bioreactor (24h), S. mutans biofilm formation in a continuous-flow bioreactor simulating shear forces (24h), and mixed-plaque formation in the bioreactor (24h). The viable biomass adhering to the specimens' surfaces was measured using a tetrazolium dye-based test. Statistical analysis included verification of normality of distribution and homoscedasticity, then Oneway ANOVA and Tukey's test (α=5%).

RESULTS: When using the bioreactor setup, CAD/CAM RBCs generally yielded lower S. mutans and mixed-plaque biofilm formation compared to direct RBCs. This difference was not evidenced in the first two microbiological models. Differences in manufacturing and curing processes rather than in materials' surface roughness and composition could explain these results.

SIGNIFICANCE: CAD/CAM RBCs are promising materials from a microbiological point of view, featuring reduced biofilm formation on their surfaces when shear conditions similar to in vivo ones are present.}, } @article {pmid32236723, year = {2020}, author = {Vieira, TI and Alexandria, AK and Menezes, JCV and do Amaral, LH and Dos Santos, TMP and Neves, AA and Lopes, RT and Cabral, LM and Valença, AMG and Maia, LC}, title = {Characterization and effect of nanocomplexed fluoride solutions on the inhibition of enamel demineralization created by a multispecies cariogenic biofilm model.}, journal = {Clinical oral investigations}, volume = {24}, number = {11}, pages = {3947-3959}, pmid = {32236723}, issn = {1436-3771}, support = {E-26/202.924/2017//FAPERJ/ ; 303535/2016-4//CNPq/ ; 001//CAPES/ ; }, mesh = {Biofilms ; Cariostatic Agents ; Dental Enamel ; *Fluorides ; Minerals ; *Sodium Fluoride ; Titanium ; }, abstract = {OBJECTIVES: The aim of this study was to assess the in vitro caries preventive effect of nanocomplexed solutions of hydroxypropyl-β-cyclodextrin and γ-cyclodextrin associated with titanium tetrafluoride (TiF4) after different complexation times (12 or 72 h).

MATERIALS AND METHODS: Enamel blocks were randomly distributed in 9 groups (n = 11): negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, TiF4, hydroxypropyl-β-cyclodextrin:TiF4 12 h, hydroxypropyl-β-cyclodextrin:TiF4 72 h, γ-cyclodextrin:TiF4 12 h, γ-cyclodextrin:TiF4 72 h, and NaF (positive control). The solutions were applied for 1 min and the blocks were exposed to a biofilm model. Nanocompounds were characterized by differential scanning calorimetry and X-ray powder diffraction. The percentage of surface microhardness loss (%SML), mineral density changes (ΔZ), lesion depth, surface morphology (scanning electron microscopy-SEM), and chemical characterization (energy-dispersive spectroscopy-EDS) were assessed.

RESULTS: No oxidation was observed, and the formation of the nanocomplexes was evidenced by changes in the melting point compared to pure cyclodextrins and the loss of crystallinity of the materials. Hydroxypropyl-β-cyclodextrin:TiF4 72 h resulted in lower %SML than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, and TiF4 (p < 0.05). NaF differed from all groups (p < 0.05), except for hydroxypropyl-β-cyclodextrin:TiF4 72 h (p = 0.83). ΔZ of hydroxypropyl-β-cyclodextrin:TiF4 72 h was higher than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, γ-cyclodextrin:TiF4 1 2 h, γ-cyclodextrin:TiF4 72 h, and NaF (p < 0.05) and similar to TiF4 and hydroxypropyl-β-cyclodextrin:TiF4 12 h (p > 0.05). SEM/EDS detected Ti in the blocks subjected to TiF4-products.

CONCLUSION: The hydroxypropyl-β-cyclodextrin:TiF4 72 h solution showed caries preventive effect on the surface and subsurface of the enamel.

CLINICAL RELEVANCE: A hydroxypropyl-β-cyclodextrin nanosystem, in association with TiF4 after 72 h of complexation, may be a promising agent for the prevention of enamel demineralization.}, } @article {pmid32236357, year = {2020}, author = {Kim, T and Kim, MA and Hwang, YC and Rosa, V and Del Fabbro, M and Min, KS}, title = {Effect of a calcium hydroxide-based intracanal medicament containing N-2-methyl pyrrolidone as a vehicle against Enterococcus faecalis biofilm.}, journal = {Journal of applied oral science : revista FOB}, volume = {28}, number = {}, pages = {e20190516}, pmid = {32236357}, issn = {1678-7765}, mesh = {Analysis of Variance ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Calcium Chloride/chemistry/pharmacology ; Calcium Hydroxide/chemistry/*pharmacology ; Cattle ; Colony Count, Microbial ; Drug Combinations ; Enterococcus faecalis/*drug effects ; Materials Testing ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Potassium Chloride/chemistry/pharmacology ; Pyrrolidinones/chemistry/*pharmacology ; Reproducibility of Results ; Root Canal Irrigants/chemistry/*pharmacology ; Sodium Bicarbonate/chemistry/pharmacology ; Sodium Chloride/chemistry/pharmacology ; Statistics, Nonparametric ; }, abstract = {INTRODUCTION: This study investigated the effect of a calcium hydroxide (CH) paste (CleaniCal®) containing N-2-methyl pyrrolidone (NMP) as a vehicle on Enterococcus faecalis (E. faecalis) biofilms compared with other products containing saline (Calasept Plus™) or propylene glycol (PG) (Calcipex II®).

METHODOLOGY: Standardized bovine root canal specimens were used. The antibacterial effects were measured by colony-forming unit counting. The thickness of bacterial microcolonies and exopolysaccharides was assessed using confocal laser scanning microscopy. Morphological features of the biofilms were observed using field-emission scanning electron microscopy (FE-SEM). Bovine tooth blocks covered with nail polish were immersed into the vehicles and dispelling was observed. The data were analyzed using one-way analysis of variance and Tukey tests (p<0.05).

RESULTS: CleaniCal® showed the highest antibacterial activity, followed by Calcipex II® (p<0.05). Moreover, NMP showed a higher antibacterial effect compared with PG (p<0.05). The thickness of bacteria and EPS in the CleaniCal® group was significantly lower than that of other materials tested (p<0.05). FE-SEM images showed the specimens treated with Calasept Plus™ were covered with biofilms, whereas the specimens treated with other medicaments were not. Notably, the specimen treated with CleaniCal® was cleaner than the one treated with Calcipex II®. Furthermore, the nail polish on the bovine tooth block immersed in NMP was completely dispelled.

CONCLUSIONS: CleaniCal® performed better than Calasept Plus™ and Calcipex II® in the removal efficacy of E. faecalis biofilms. The results suggest the effect might be due to the potent dissolving effect of NMP on organic substances.}, } @article {pmid32236356, year = {2020}, author = {Ayoub, HM and Gregory, RL and Tang, Q and Lippert, F}, title = {Influence of salivary conditioning and sucrose concentration on biofilm-mediated enamel demineralization.}, journal = {Journal of applied oral science : revista FOB}, volume = {28}, number = {}, pages = {e20190501}, pmid = {32236356}, issn = {1678-7765}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Dental Enamel/chemistry/*microbiology ; Dental Pellicle/microbiology ; Hardness ; Microradiography/methods ; Pasteurization ; Reference Values ; Saliva/*chemistry/microbiology ; Sucrose/analysis/*chemistry ; Surface Properties ; Tooth Demineralization/*microbiology ; }, abstract = {INTRODUCTION: The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types.

OBJECTIVE: To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization.

METHODOLOGY: Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA.

RESULTS: The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001).

CONCLUSION: Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.}, } @article {pmid32236097, year = {2020}, author = {Bundalovic-Torma, C and Whitfield, GB and Marmont, LS and Howell, PL and Parkinson, J}, title = {A systematic pipeline for classifying bacterial operons reveals the evolutionary landscape of biofilm machineries.}, journal = {PLoS computational biology}, volume = {16}, number = {4}, pages = {e1007721}, pmid = {32236097}, issn = {1553-7358}, support = {R21 AI126466/AI/NIAID NIH HHS/United States ; MOP 43998//CIHR/Canada ; FDN154327//CIHR/Canada ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/growth & development ; Biological Evolution ; Computational Biology/*methods ; Evolution, Molecular ; Gene Duplication ; Operon/*genetics/*physiology ; Phylogeny ; Virulence Factors ; }, abstract = {In bacteria functionally related genes comprising metabolic pathways and protein complexes are frequently encoded in operons and are widely conserved across phylogenetically diverse species. The evolution of these operon-encoded processes is affected by diverse mechanisms such as gene duplication, loss, rearrangement, and horizontal transfer. These mechanisms can result in functional diversification, increasing the potential evolution of novel biological pathways, and enabling pre-existing pathways to adapt to the requirements of particular environments. Despite the fundamental importance that these mechanisms play in bacterial environmental adaptation, a systematic approach for studying the evolution of operon organization is lacking. Herein, we present a novel method to study the evolution of operons based on phylogenetic clustering of operon-encoded protein families and genomic-proximity network visualizations of operon architectures. We applied this approach to study the evolution of the synthase dependent exopolysaccharide (EPS) biosynthetic systems: cellulose, acetylated cellulose, poly-β-1,6-N-acetyl-D-glucosamine (PNAG), Pel, and alginate. These polymers have important roles in biofilm formation, antibiotic tolerance, and as virulence factors in opportunistic pathogens. Our approach revealed the complex evolutionary landscape of EPS machineries, and enabled operons to be classified into evolutionarily distinct lineages. Cellulose operons show phyla-specific operon lineages resulting from gene loss, rearrangement, and the acquisition of accessory loci, and the occurrence of whole-operon duplications arising through horizonal gene transfer. Our evolution-based classification also distinguishes between PNAG production from Gram-negative and Gram-positive bacteria on the basis of structural and functional evolution of the acetylation modification domains shared by PgaB and IcaB loci, respectively. We also predict several pel-like operon lineages in Gram-positive bacteria and demonstrate in our companion paper (Whitfield et al PLoS Pathogens, in press) that Bacillus cereus produces a Pel-dependent biofilm that is regulated by cyclic-3',5'-dimeric guanosine monophosphate (c-di-GMP).}, } @article {pmid32235590, year = {2020}, author = {Cáceres, M and Hidalgo, W and Stashenko, E and Torres, R and Ortiz, C}, title = {Essential Oils of Aromatic Plants with Antibacterial, Anti-Biofilm and Anti-Quorum Sensing Activities against Pathogenic Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32235590}, issn = {2079-6382}, support = {1102-777-57586//Departamento Administrativo de Ciencia, Tecnología e Innovación (COLCIENCIAS)/ ; }, abstract = {Both the ability of bacteria to form biofilms and communicate through quorum sensing allows them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, seventeen essential oils (EOs) were investigated for the antimicrobial, antibiofilm, and anti-quorum sensing activities on Escherichia. coli O157:H7, Escherichia coli O33, and Staphylococcus epidermidis ATCC 12228. All essential oils were isolated from plant material by using hydrodistillation and analyzed by GC-MS. The antimicrobial activity was performed by using the microdilution technique. Subinhibitory concentrations of each EO were assayed for biofilm inhibition in both bacterial strains. Quantification of violacein in Chromobacterium violaceum CV026 was performed for the anti-quorum sensing activity. The cytotoxicity activity of the EOs was evaluated on Vero cell line by using MTT method. Thymol-carvacrol-chemotype (I and II) oils from Lippia origanoides and Thymus vulgaris oil exhibited the higher antimicrobial activity with MIC values of 0.37-0.75 mg/mL. In addition, these EOs strongly inhibited the biofilm formation and violacein (QS) production in a concentration-dependent manner, highlighting thymol-carvacrol-chemotype (II) oil as the best candidate for further studies in antibiotic design and development against bacterial resistance.}, } @article {pmid32235332, year = {2020}, author = {Namour, M and Verspecht, T and El Mobadder, M and Teughels, W and Peremans, A and Nammour, S and Rompen, E}, title = {Q-Switch Nd:YAG Laser-Assisted Elimination of Multi-Species Biofilm on Titanium Surfaces.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {7}, pages = {}, pmid = {32235332}, issn = {1996-1944}, abstract = {(1) Background: The relatively high prevalence of peri-implantitis (PI) and the lack of a standard method for decontamination of the dental implant surface have pushed us to conduct further research in the field. Bacterial biofilms were found to play a primordial role in the etiology of PI. Therefore, the aim is to evaluate the efficacy of a laser-assisted elimination of biofilm protocol in the removal of a multi-species biofilm on titanium surfaces. (2) Methods: In total, 52 titanium discs (grade 4) were used. The study group consisted of 13 titanium disks contaminated with multi-species biofilms and subsequently irradiated with the laser (T + BF + L). The control groups consisted of the following types of titanium disks: 13 contaminated with multi-species biofilms (T + BF), 13 sterile and irradiated (T + L), 13 sterile and untreated (T). Q-Switch Nd:YAG laser Irradiation parameters were the following: energy density equal to 0.597 J/cm[2] per pulse, power equal to 270 milliwatt per pulse, 2.4 mm of spot diameter, and 10 Hz repetition rate for pulse duration of six nanoseconds (ns). The laser irradiation was made during 2 s of total time in non-contact and at 0.5 mm away from the titanium disc surface. After treatment, presence of biofilms on the disks was evaluated by staining with crystal violet (CV), which was measured as optical density at six hundred thirty nm, and statistical analyses were done. (3) Results: the optical density values were 0.004 ± 0.004 for the study group T + BF + L, 0.120 ± 0.039 for group T + BF, 0.006 ± 0.003 for group T + L, and 0.007 ± 0.007 for group T. For the study group, laser treatment resulted in a total elimination of the biofilm, with mean values statistically significantly lower than those of contaminated titanium surfaces and similar to those of sterile titanium surfaces. (4) Conclusions: Our irradiation protocol provided a significant elimination of the multi-species biofilm on titanium surfaces. Laser treated titanium surfaces were biofilm-free, similar to the sterile ones.}, } @article {pmid32233822, year = {2020}, author = {Abusrewil, S and Alshanta, OA and Albashaireh, K and Alqahtani, S and Nile, CJ and Scott, JA and McLean, W}, title = {Detection, treatment and prevention of endodontic biofilm infections: what's new in 2020?.}, journal = {Critical reviews in microbiology}, volume = {46}, number = {2}, pages = {194-212}, doi = {10.1080/1040841X.2020.1739622}, pmid = {32233822}, issn = {1549-7828}, mesh = {Animals ; Bacteria/genetics/isolation & purification ; Bacterial Infections/microbiology/*prevention & control ; Bacterial Physiological Phenomena ; *Biofilms ; Dental Pulp Cavity/microbiology ; Dental Pulp Diseases/microbiology/*prevention & control ; Endodontics ; Humans ; }, abstract = {Endodontic disease, a biofilm infection of the root canal space, is a significant cause of dental morbidity worldwide. Endodontic treatment, or root canal treatment, as it is commonly known is founded on the ability to eradicate microbial biofilm infection and prevent re-infection of the highly complex root canal space. Despite many "advances" in clinical endodontics we have seen little improvement in outcomes. The aim of this critical review paper is to provide a contemporary view of endodontic microbiology and biofilm polymicrobiality, provide an understanding of the host response, and how together these impact upon clinical treatment. Ultimately, it is intended to provide insight into novel opportunities and strategies for the future diagnostics, treatment, and prevention of endodontic disease.}, } @article {pmid32233533, year = {2020}, author = {Rohanizadegan, Y and Sonner, S and Eberl, HJ}, title = {Discrete attachment to a cellulolytic biofilm modeled by an Itô stochastic differential equation.}, journal = {Mathematical biosciences and engineering : MBE}, volume = {17}, number = {3}, pages = {2236-2271}, doi = {10.3934/mbe.2020119}, pmid = {32233533}, issn = {1551-0018}, mesh = {*Biofilms ; Biomass ; Computer Simulation ; *Models, Biological ; Stochastic Processes ; }, abstract = {We propose a mathematical framework for introducing random attachment of bacterial cells in a deterministic continuum model of cellulosic biofilms. The underlying growth model is a highly nonlinear coupled PDE-ODE system. It is regularised and discretised in space. Attachment is described then via an auxiliary stochastic process that induces impulses in the biomass equation. The resulting system is an Itô stochastic differential equation. Unlike the more direct approach of modeling attachment by additive noise, the proposed model preserves non-negativity of solutions. Our numerical simulations are able to reproduce characteristic features of cellulolytic biofilms with cell attachment from the aqueous phase. Grid refinement studies show convergence for the expected values of spatially integrated biomass density and carbon concentration. We also examine the sensitivity of the model with respect to the parameters that control random attachment.}, } @article {pmid32232531, year = {2020}, author = {Li, C and Jiang, C and Jing, H and Jiang, C and Wang, H and Du, X and Lou, Z}, title = {Separation of phenolics from peony flowers and their inhibitory activities and action mechanism on bacterial biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {10}, pages = {4321-4332}, doi = {10.1007/s00253-020-10540-z}, pmid = {32232531}, issn = {1432-0614}, support = {JUFSTR20180204//National Resource Center for the First-Year Experience and Students in Transition, University of South Carolina (US)/ ; 2017YFD0400803//Guangxi Talent Highland of Preservation and Deep Processing Research in Fruit and Vegetables (CN)/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Flowers/chemistry ; Microbial Sensitivity Tests ; Paeonia/*chemistry ; Phenols/isolation & purification/*pharmacology ; Quorum Sensing/drug effects ; }, abstract = {Separation and enrichment of phenolics from peony flowers were performed to improve the anti-biofilm and antibacterial activities for the first time. Through several times of separation, the purity of phenolics components increased significantly, and the anti-biofilm and antibacterial activities of phenolics components against E. coli and S. aureus were also significantly improved. Finally, the phenolics of peony flowers in the eluent of silica gel column chromatography (PPF-ESGCC) were found to exhibit the highest anti-biofilm and antibacterial activities. The inhibition rates of PPF-ESGCC on biofilms of E. coli and S. aureus were 77.93%, and 87.03% respectively, at a very low concentration (1/2 MIC, 0.235 mg/mL). It was found that the biofilm inhibition was achieved by inhibiting their swimming, swarming, twitching motilities, exopolysaccharide (EPS) production, and quorum sensing (QS). Moreover, there was a positive dose-dependent relationship (r = 0.75 to 1) between the inhibition rates and concentrations of PPF-ESGCC during the critical biofilm-formation stage (1-3 days). Chemical composition analysis showed the PPF-ESGCC comprised of gallic acid, kaempferol-7-O-glucoside, and apigenin-7-O-glucoside. In conclusion, PPF-ESGCC exhibited strong inhibitory effect on biofilm formation and gallic acid, kaempferol-7-O-glucoside, and apigenin-7-O-glucoside might play a crucial role in inhibiting biofilm formation. Meanwhile, this study indicated that PPF-ESGCC, a new natural QS inhibitor and biofilm inhibitor, could be used as a novel intervention strategy to enhance the safety and quality of food.}, } @article {pmid32232239, year = {2020}, author = {Qian, Y and Altamimi, A and Yates, SA and Sarkar, S and Cochran, M and Zhou, M and Levi-Polyachenko, N and Matson, JB}, title = {H2S-releasing amphiphilic dipeptide hydrogels are potent S. aureus biofilm disruptors.}, journal = {Biomaterials science}, volume = {8}, number = {9}, pages = {2564-2576}, pmid = {32232239}, issn = {2047-4849}, support = {R01 GM123508/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/drug effects ; Dipeptides/*administration & dosage/chemistry ; Hydrogels/*administration & dosage ; Hydrogen Sulfide/*chemistry ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {As a gasotransmitter, hydrogen sulfide (H2S) has been studied to treat wounds and inflammation, but its potential antimicrobial effects in this context have not been evaluated. An H2S-releasing dipeptide hydrogel (S-FE), and several non-H2S-releasing control dipeptides, (C-FE, C-GE, FBA-FE, and FE where S = S-aroylthiooxime, an H2S donor; C = control, an oxime incapable of H2S release; FBA = 4-formylbenzamide, also incapable of H2S release; and E, F, G = glutamic acid, phenylalanine, and glycine, respectively), were studied to correlate differences in their chemical structures and H2S-releasing abilities with their antimicrobial effects on Staphylococcus aureus bacteria. Dipeptides with Phe (S-FE, C-FE, and FE) self-assembled into nanoribbons in water and displayed β-sheet formation and enhanced fluorescence, while the other two dipeptides (FBA-FE and C-GE) did not form assemblies in water. In vitro experiments with Staphylococcus aureus, which is a commonly found bacterium associated with wounds, showed significant antimicrobial effects from some of the dipeptides. Dipeptide S-FE inhibited bacterial growth more effectively than any of the controls, thereby limiting biofilm formation or disrupting established biofilms. These antimicrobial H2S-releasing dipeptide hydrogels provide a promising new approach to treat wound infections.}, } @article {pmid32232010, year = {2020}, author = {Dean, SN and Milton, ME and Cavanagh, J and van Hoek, ML}, title = {Francisella novicida Two-Component System Response Regulator BfpR Modulates iglC Gene Expression, Antimicrobial Peptide Resistance, and Biofilm Production.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {82}, pmid = {32232010}, issn = {2235-2988}, support = {R01 GM055769/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Antimicrobial Cationic Peptides/pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Blood Proteins/pharmacology ; Cathelicidins/pharmacology ; Drug Resistance, Bacterial ; Francisella/drug effects/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Macrophages/microbiology ; Moths/microbiology ; Mutation ; Pore Forming Cytotoxic Proteins/*pharmacology ; Virulence/genetics ; Virulence Factors/*genetics/metabolism ; }, abstract = {Response regulators are a critical part of the two-component system of gene expression regulation in bacteria, transferring a signal from a sensor kinase into DNA binding activity resulting in alteration of gene expression. In this study, we investigated a previously uncharacterized response regulator in Francisella novicida, FTN_1452 that we have named BfpR (Biofilm-regulating Francisella protein Regulator, FTN_1452). In contrast to another Francisella response regulator, QseB/PmrA, BfpR appears to be a negative regulator of biofilm production, and also a positive regulator of antimicrobial peptide resistance in this bacterium. The protein was crystallized and X-ray crystallography studies produced a 1.8 Å structure of the BfpR N-terminal receiver domain revealing interesting insight into its potential interaction with the sensor kinase. Structural analysis of BfpR places it in the OmpR/PhoP family of bacterial response regulators along with WalR and ResD. Proteomic and transcriptomic analyses suggest that BfpR overexpression affects expression of the critical Francisella virulence factor iglC, as well as other proteins in the bacterium. We demonstrate that mutation of bfpR is associated with an antimicrobial peptide resistance phenotype, a phenotype also associated with other response regulators, for the human cathelicidin peptide LL-37 and a sheep antimicrobial peptide SMAP-29. F. novicida with mutated bfpR replicated better than WT in intracellular infection assays in human-derived macrophages suggesting that the down-regulation of iglC expression in bfpR mutant may enable this intracellular replication to occur. Response regulators have been shown to play important roles in the regulation of bacterial biofilm production. We demonstrate that F. novicida biofilm formation was highly increased in the bfpR mutant, corresponding to altered glycogen synthesis. Waxworm infection experiments suggest a role of BfpR as a negative modulator of iglC expression with de-repression by Mg[2+]. In this study, we find that the response regulator BfpR may be a negative regulator of biofilm formation, and a positive regulator of antimicrobial peptide resistance in F. novicida.}, } @article {pmid32231093, year = {2020}, author = {Papaianni, M and Cuomo, P and Fulgione, A and Albanese, D and Gallo, M and Paris, D and Motta, A and Iannelli, D and Capparelli, R}, title = {Bacteriophages Promote Metabolic Changes in Bacteria Biofilm.}, journal = {Microorganisms}, volume = {8}, number = {4}, pages = {}, pmid = {32231093}, issn = {2076-2607}, abstract = {Bacterial biofilm provides bacteria with resistance and protection against conventional antimicrobial agents and the host immune system. Bacteriophages are known to move across the biofilm to make it permeable to antimicrobials. Mineral hydroxyapatite (HA) can improve the lytic activity of bacteriophages, and, together with eicosanoic acid (C20:0), can destroy the biofilm structure. Here, we demonstrate the efficacy of the combined use of phage, HA and C20:0 against Xanthomonas campestris pv campestris (Xcc) biofilm. We used nuclear magnetic resonance (NMR)-based metabolomics to investigate the molecular determinants related to the lytic action, aiming at identifying the metabolic pathways dysregulated by phage treatment. Furthermore, we identified specific markers (amino acids, lactate and galactomannan) which are involved in the control of biofilm stability. Our data show that Xccφ1, alone or in combination with HA and C20:0, interferes with the metabolic pathways involved in biofilm formation. The approach described here might be extended to other biofilm-producing bacteria.}, } @article {pmid32230813, year = {2020}, author = {Mettrick, K and Hassan, K and Lamont, I and Reid, D}, title = {The Iron-chelator, N,N'-bis (2-hydroxybenzyl) Ethylenediamine-N,N'-Diacetic acid is an Effective Colistin Adjunct against Clinical Strains of Biofilm-Dwelling Pseudomonas aeruginosa.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {4}, pages = {}, pmid = {32230813}, issn = {2079-6382}, support = {352611//National Health and Medical Research Council/ ; N/A//Royal Hobart Hospital Research Foundation/ ; N/A//Australian Cystic Fibrosis Research Trust/ ; }, abstract = {Targeting the iron requirement of Pseudomonas aeruginosa may be an effective adjunctive for conventional antibiotic treatment against biofilm-dwelling P. aeruginosa. We, therefore, assessed the anti-biofilm activity of N,N'-bis (2-hydroxybenzyl) ethylenediamine-N,N'-diacetic acid (HBED), which is a synthetic hexadentate iron chelator. The effect of HBED was studied using short-term (microtitre plate) and longer-term (flow-cell) biofilm models, under aerobic, anaerobic, and microaerobic (flow-cell) conditions and in combination with the polymyxin antibiotic colistimethate sodium (colistin). HBED was assessed against strains of P. aeruginosa from patients with cystic fibrosis and the reference strain PAO1. HBED inhibited growth and biofilm formation of all clinical strains under aerobic and anaerobic conditions, but inhibitory effects against PAO1 were predominantly exerted under anaerobic conditions. PA605, which is a clinical strain with a robust biofilm-forming phenotype, was selected for flow-cell studies. HBED significantly reduced biomass and surface coverage of PA605, and, combined with colistin, HBED significantly enhanced the microcolony killing effects of colistin to result in almost complete removal of the biofilm. HBED combined with colistin is highly effective in vitro against biofilms formed by clinical strains of P. aeruginosa.}, } @article {pmid32229312, year = {2020}, author = {Ríos-Castillo, AG and Ripolles-Avila, C and Rodríguez-Jerez, JJ}, title = {Detection of Salmonella Typhimurium and Listeria monocytogenes biofilm cells exposed to different drying and pre-enrichment times using conventional and rapid methods.}, journal = {International journal of food microbiology}, volume = {324}, number = {}, pages = {108611}, doi = {10.1016/j.ijfoodmicro.2020.108611}, pmid = {32229312}, issn = {1879-3460}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Culture Media ; Desiccation/*methods ; Food Microbiology/*methods ; Listeria monocytogenes/growth & development/*isolation & purification ; Microbial Viability ; Salmonella typhimurium/growth & development/*isolation & purification ; Time Factors ; }, abstract = {The capacity of real-time PCR (RT-PCR), the VIDAS immunoassay system, and the conventional count method for detecting Salmonella enterica serovar Typhimurium and Listeria monocytogenes biofilm cells was evaluated in this study. After biofilm formation, tests were performed under different drying times (0, 6, 12, 24, and 72 h) and pre-enrichment times (0, 6, 18, and 25 h). The direct epifluorescence microscopic results demonstrated that Salmonella Typhimurium and L. monocytogenes biofilm cells can remain viable for 72 h under drying conditions. Pre-enrichment time and type of medium played an essential role in the detection of both microorganisms after drying. Furthermore, RT-PCR was more sensitive than VIDAS and the conventional method for detecting Salmonella Typhimurium and L. monocytogenes cells at different drying times and without pre-enrichment (0 h), with a detection range between 10[2] and 10[7] CFU/mL. TSBYE-T80 used as a pre-enrichment medium was effective for detecting both bacteria and was more effective than Demi Fraser-T80 medium for detecting L. monocytogenes. Therefore, pre-enrichment is recommended to avoid false positives and false negatives due to the presence of dead cells or a very low initial concentration of cells after drying.}, } @article {pmid32229287, year = {2020}, author = {Srivastava, GN and Malwe, AS and Sharma, AK and Shastri, V and Hibare, K and Sharma, VK}, title = {Molib: A machine learning based classification tool for the prediction of biofilm inhibitory molecules.}, journal = {Genomics}, volume = {112}, number = {4}, pages = {2823-2832}, doi = {10.1016/j.ygeno.2020.03.020}, pmid = {32229287}, issn = {1089-8646}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; *Machine Learning ; Principal Component Analysis ; *Software ; }, abstract = {Identification of biofilm inhibitory small molecules appears promising for therapeutic intervention against biofilm-forming bacteria. However, the experimental identification of such molecules is a time-consuming task, and thus, the computational approaches emerge as promising alternatives. We developed the 'Molib' tool to predict the biofilm inhibitory activity of small molecules. We curated a training dataset of biofilm inhibitory molecules, and the structural and chemical features were used for feature selection, followed by algorithms optimization and building of machine learning-based classification models. On five-fold cross validation, Random Forest-based descriptor, fingerprint and hybrid classification models showed accuracies of 0.93, 0.88 and 0.90, respectively. The performances of all models were evaluated on two different validation datasets including biofilm inhibitory and non-inhibitory molecules, attesting to its accuracy (≥ 0.90). The Molib web server would serve as a highly useful and reliable tool for the prediction of biofilm inhibitory activity of small molecules.}, } @article {pmid32228495, year = {2020}, author = {Kosari, F and Taheri, M and Moradi, A and Hakimi Alni, R and Alikhani, MY}, title = {Evaluation of cinnamon extract effects on clbB gene expression and biofilm formation in Escherichia coli strains isolated from colon cancer patients.}, journal = {BMC cancer}, volume = {20}, number = {1}, pages = {267}, pmid = {32228495}, issn = {1471-2407}, mesh = {Anti-Infective Agents/*therapeutic use ; Biofilms ; *Cinnamomum zeylanicum ; Colonic Neoplasms/microbiology/*therapy ; Escherichia coli/genetics/*metabolism ; Escherichia coli Infections/*therapy ; Gene Expression Regulation, Bacterial ; Humans ; Oils, Volatile ; Peptides/genetics/*metabolism ; Phytotherapy ; Plant Extracts/*therapeutic use ; Polyketides/*metabolism ; }, abstract = {BACKGROUND: Colon cancer is one of the most common malignancies and the fourth leading cause of cancer-related mortality in the world. Colibactin, which is synthesized by the pks genomic island of E. coli interfere with the eukaryotic cell cycle. Cinnamon has an antimicrobial effect and considered as a colon cancer-preventing agent. The aim of the study was to evaluate the effects of cinnamon extract and cinnamaldehyde on clbB gene expression and biofilm formation in clinical isolates of E. coli.

METHODS: Thirty E. coli carrying pks gene were isolated from the colon cancer patients, inflammatory bowel disease and healthy subjects. Antibiotic susceptibility was evaluated by disk diffusion method and the minimum inhibitory concentration of cinnamon essential oil and cinnamaldehyde by microdilution broth method. In vitro biofilm formation of E.coli isolates was monitored using a microtiter plate method. The presence of clbB, clbA and clbQ genes in E.coli isolates were evaluated by PCR. The effect of cinnamaldehyde and cinnamon essential oil on clbB gene expression was evaluated by Real-Time PCR.

RESULTS: The highest antibiotic resistance was obtained with 94.4% for ticarcillin-clavulanic acid, azithromycin, amoxicillin, and amikacin. The MIC for all clinical isolates was 32 μl/ml of cinnamon essential oil and the MIC of cinnamaldehyde was between 0.00002 to 0.03 μl/ml. After exposure of isolates to cinnamon extract and cinnamaldehyde, 40 and 13.3% were weakly biofilm producers, respectively. The frequencies of clbB, clbA, and clbQ genes were 23.3, 23.3, and 26.7%, respectively. The expression of clbB gene in the presence of the Sub-MIC concentration of cinnamon essential oil and cinnamaldehyde was decreased in 8 isolates compared to untreated isolates (p-value < 0.05).

CONCLUSIONS: The antibacterial activity of cinnamaldehyde and cinnamon essential oil allows the use of these herbal compounds for treatment or supplements in infections caused by E. coli and in patients with suspected colorectal cancer.}, } @article {pmid32226914, year = {2020}, author = {Santiago, AJ and Burgos-Garay, ML and Kartforosh, L and Mazher, M and Donlan, RM}, title = {Bacteriophage treatment of carbapenemase-producing Klebsiella pneumoniae in a multispecies biofilm: a potential biocontrol strategy for healthcare facilities.}, journal = {AIMS microbiology}, volume = {6}, number = {1}, pages = {43-63}, pmid = {32226914}, issn = {2471-1888}, abstract = {The p-traps of hospital handwashing sinks represent a potential reservoir for antimicrobial-resistant organisms of major public health concern, such as carbapenemase-producing KPC+ Klebsiella pneumoniae (CPKP). Bacteriophages have reemerged as potential biocontrol agents, particularly against biofilm-associated, drug-resistant microorganisms. The primary objective of our study was to formulate a phage cocktail capable of targeting a CPKP strain (CAV1016) at different stages of colonization within polymicrobial drinking water biofilms using a CDC biofilm reactor (CBR) p-trap model. A cocktail of four CAV1016 phages, all exhibiting depolymerase activity, were isolated from untreated wastewater using standard methods. Biofilms containing Pseudomonas aeruginosa, Micrococcus luteus, Stenotrophomonas maltophilia, Elizabethkingia anophelis, Cupriavidus metallidurans, and Methylobacterium fujisawaense were established in the CBR p-trap model for a period of 28 d. Subsequently, CAV1016 was inoculated into the p-trap model and monitored over a period of 21 d. Biofilms were treated for 2 h at either 25 °C or 37 °C with the phage cocktail (10[9] PFU/ml) at 7, 14, and 21 d post-inoculation. The effect of phage treatment on the viability of biofilm-associated CAV1016 was determined by plate count on m-Endo LES agar. Biofilm heterotrophic plate counts (HPC) were determined using R2A agar. Phage titers were determined by plaque assay. Phage treatment reduced biofilm-associated CAV1016 viability by 1 log10 CFU/cm[2] (p < 0.05) at 7 and 14 d (37 °C) and 1.4 log10 and 1.6 log10 CFU/cm[2] (p < 0.05) at 7 and 14 d, respectively (25 °C). No significant reduction was observed at 21 d post-inoculation. Phage treatment had no significant effect on the biofilm HPCs (p > 0.05) at any time point or temperature. Supplementation with a non-ionic surfactant appears to enhance phage association within biofilms. The results of this study suggest the potential of phages to control CPKP and other carbapenemase-producing organisms associated with microbial biofilms in the healthcare environment.}, } @article {pmid32224409, year = {2020}, author = {Hu, J and Wang, C and Shao, B and Fu, L and Yu, J and Qiang, Z and Chen, J}, title = {Enhanced formation of carbonaceous and nitrogenous disinfection byproducts from biofilm extracellular polymeric substances undercatalysis of copper corrosion products.}, journal = {The Science of the total environment}, volume = {723}, number = {}, pages = {138160}, doi = {10.1016/j.scitotenv.2020.138160}, pmid = {32224409}, issn = {1879-1026}, mesh = {Biofilms ; Copper ; Corrosion ; *Disinfectants ; Disinfection ; Extracellular Polymeric Substance Matrix ; Halogenation ; Nitrogen/analysis ; Water Pollutants, Chemical/*analysis ; *Water Purification ; }, abstract = {Biofilm formation is ubiquitous on the corroded inner surface of water distribution pipes. Extracellular polymeric substances (EPS) secreted by biofilm microorganisms are nonnegligible precursors of disinfection byproducts (DBPs). The aim was to study the catalysis of copper corrosion products (CCPs, CuO and Cu[2+]) on the formation of carbonaceous and nitrogenous DBPs (C-DBPs and N-DBPs) with EPS as a precursor. Results indicate that CCPs had a remarkable enhancement on the formation of DBPs, especially N-DBPs. The enhancement by Cu[2+] was mainly via homogeneous catalysis initiating from its complexation with EPS, while that by CuO was primarily through heterogeneous catalysis initiating from the polarization of Cl atom in HOCl/OCl[-]. The enhancement was more evident as pH increased because an alkaline condition favored the electrostatic interactions of CCPs with EPS and HOCl/OCl[-]. The presence of Br[-] weakened the enhancement, which may be attributed to that HOBr/OBr[-] had a much higher reaction rate than HOCl/OCl[-] towards the low reactive moieties in EPS. Due to more phenolic or unsaturated/conjugated groups, EPS proteins had a higher catalytic formation of DBPs than EPS polysaccharides. Among the major amino acids in EPS proteins for DBPs formation, tyrosine had the highest enhancement on the formation of trihalomethanes, while histidine had the highest catalytic formation of halogenated acetic acids, acetonitriles and acetamides. The study helps to understand the formation of DBPs by the joint actions of EPS and CCPs in drinking water distribution systems.}, } @article {pmid32224208, year = {2020}, author = {Qais, FA and Shafiq, A and Ahmad, I and Husain, FM and Khan, RA and Hassan, I}, title = {Green synthesis of silver nanoparticles using Carum copticum: Assessment of its quorum sensing and biofilm inhibitory potential against gram negative bacterial pathogens.}, journal = {Microbial pathogenesis}, volume = {144}, number = {}, pages = {104172}, doi = {10.1016/j.micpath.2020.104172}, pmid = {32224208}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Carum/metabolism ; Chromobacterium/drug effects ; Drug Resistance, Multiple, Bacterial/physiology ; Indoles/metabolism ; Locomotion/drug effects ; Metal Nanoparticles/*chemistry ; Plant Extracts/chemistry/pharmacology ; Prodigiosin/biosynthesis ; Pseudomonas aeruginosa/drug effects ; Pyocyanine/biosynthesis ; Quorum Sensing/*drug effects ; Serratia marcescens/drug effects ; Silver/*pharmacology ; Virulence Factors/*antagonists & inhibitors ; Wound Infection/drug therapy/microbiology ; }, abstract = {Antimicrobial resistance among pathogenic bacteria has become a global threat to human health. Due to poor progress in development of new antimicrobial drugs, there is a need for the development of novel alternative strategies to combat the problem of multidrug resistance. Moreover, there is focus on ecofriendly approach for the synthesis nanoparticles having efficient medicinal properties including antivirulence properties to tackle the emergence of multi-drug resistance. Targeting quorum sensing controlled virulence factors and biofilms has come out to be a novel anti-infective drug target. The silver nanoparticles (Ag@CC-NPs) were synthesized from aqueous extract of Carum copticum and characterized using UV-vis absorption spectroscopy, fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Ag@CC-NPs were checked for its ability to inhibit quorum sensing-mediated virulence factors and biofilms against three test pathogens at sub-MIC values. There was ~75% inhibition of violacein production by Ag@CC-NPs against C. violaceum. The P. aeruginosa virulence factors such as pyocyanin production, pyoverdin production, exoprotease activity, elastase activity, swimming motility and rhamnolipid production were inhibited by 76.9, 49.0, 71.1, 53.3, 89.5, and 60.0% at sub-MIC. Moreover, virulence factors of S. marcescens viz. prodigiosin production, exoprotease activity, and swarming motility was reduced by 78.4, 67.8, and 90.7%. Ag@CC-NPs also exhibited broad-spectrum antibiofilm activity with 77.6, 86.3, and 75.1% inhibition of biofilms of P. aeruginosa, S. marcescens, and C. violaceum respectively. The biofilm formation on glass coverslip was reduced remarkably as evident from SEM and CLSM analysis. The findings revealed the in vitro efficacy of Ag@CC-NPs against bacterial pathogens and can be exploited in the development of alternative therapeutic agent in management of bacterial infections for topical application, mainly wound infection, or coating of surfaces to prevent bacterial adherence on medical devices.}, } @article {pmid32224190, year = {2020}, author = {Hamada, M and Yamaguchi, T and Ishii, Y and Chono, K and Tateda, K}, title = {Inhibitory effect of fidaxomicin on biofilm formation in Clostridioides difficile.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {26}, number = {7}, pages = {685-692}, doi = {10.1016/j.jiac.2020.02.014}, pmid = {32224190}, issn = {1437-7780}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Clostridioides difficile/*drug effects/genetics ; Clostridium Infections/*drug therapy/microbiology ; Fidaxomicin/*pharmacology/therapeutic use ; Flagellin/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; RNA, Bacterial/biosynthesis/isolation & purification ; RNA, Messenger/biosynthesis/isolation & purification ; Transcription, Genetic/drug effects ; }, abstract = {Clostridioides difficile infection results from a disturbance of the normal microbial flora of the colon, allowing proliferation of C. difficile and toxin production by toxigenic strains. Fidaxomicin, a macrocyclic antibiotic that prevents RNA synthesis in C. difficile and inhibits spore formation, toxin production, and cell proliferation, is clinically effective in treating C. difficile infection. As recent studies have suggested that biofilm formation influences C. difficile colonization and infection in the colon, we undertook the present study to determine the effects of fidaxomicin on C. difficile biofilm formation. Sub-minimum inhibitory concentrations (MICs) of fidaxomicin inhibited biofilm formation by C. difficile UK027 and delayed planktonic growth. Sub-MICs of vancomycin did not inhibit biofilm formation or affect planktonic growth. In C. difficile UK027 exposed to sub-MICs of fidaxomicin, mRNA expression of biofilm-related flagellin gene fliC was slightly increased compared with that of other biofilm-related genes (pilA1, cwp84, luxS, dccA, and spo0A). In conclusion, this study indicates that sub-MICs of fidaxomicin inhibit C. difficile UK027 biofilm formation by influencing cell growth and fliC transcription.}, } @article {pmid32221908, year = {2020}, author = {Caraballo Guzmán, A and González Hurtado, MI and Cuesta-Astroz, Y and Torres, G}, title = {Metagenomic characterization of bacterial biofilm in four food processing plants in Colombia.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {3}, pages = {1259-1267}, pmid = {32221908}, issn = {1678-4405}, support = {55965//Colciencias/ ; }, mesh = {Bacteria/classification/*genetics/isolation & purification ; *Biofilms ; Colombia ; Disinfection ; Equipment Contamination/*statistics & numerical data ; Food Handling/*instrumentation ; Metagenome ; Metagenomics ; *Microbiota ; }, abstract = {Bacteria inside biofilms are more persistent and resistant to stress conditions found in the production environment of food processing plants, thus representing a constant risk for product safety and quality. Therefore, the aim of this study was to characterize, using 16S rRNA sequencing, the bacterial communities from biofilms found in four food processing plants (P1, P2, P3, and P4). In total, 50 samples from these four processing plants were taken after cleaning and disinfection processes. Four phyla: Proteobacteria, Firmicutes, Actinobacteria, and Bacteroides represented over 94% of the operational taxonomic units found across these four plants. A total of 102 families and 189 genera were identified. Two genera, Pseudomonas spp. and Acinetobacter spp., were the most frequently found (93.47%) across the four plants. In P1, Pseudomonas spp. and Lactobacillus spp. were the dominant genera, whereas Lactobacillus spp. and Streptococcus spp. were identified in P2. On the other hand, biofilms found in P3 and P4 mainly consisted of Pseudomonas spp. and Acinetobacter spp. Our results indicate that different bacterial genera of interest to the food industry due to their ability to form biofilm and affect food quality can coexist inside biofilms, and as such, persist in production environments, representing a constant risk for manufactured foods. In addition, the core microbiota identified across processing plants evaluated was probably influenced by type of food produced and cleaning and disinfection processes performed in each one of these.}, } @article {pmid32221298, year = {2020}, author = {Taglialegna, A and Matilla-Cuenca, L and Dorado-Morales, P and Navarro, S and Ventura, S and Garnett, JA and Lasa, I and Valle, J}, title = {The biofilm-associated surface protein Esp of Enterococcus faecalis forms amyloid-like fibers.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {15}, pmid = {32221298}, issn = {2055-5008}, mesh = {Amyloid/metabolism ; Bacterial Adhesion ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Enterococcus faecalis/metabolism/*physiology ; Hydrogen-Ion Concentration ; Membrane Proteins/*chemistry/genetics/*metabolism ; Protein Aggregates ; Protein Domains ; Recombinant Proteins/chemistry/metabolism ; }, abstract = {Functional amyloids are considered as common building block structures of the biofilm matrix in different bacteria. In previous work, we have shown that the staphylococcal surface protein Bap, a member of the Biofilm-Associated Proteins (BAP) family, is processed and the fragments containing the N-terminal region become aggregation-prone and self-assemble into amyloid-like structures. Here, we report that Esp, a Bap-orthologous protein produced by Enterococcus faecalis, displays a similar amyloidogenic behavior. We demonstrate that at acidic pH the N-terminal region of Esp forms aggregates with an amyloid-like conformation, as evidenced by biophysical analysis and the binding of protein aggregates to amyloid-indicative dyes. Expression of a chimeric protein, with its Esp N-terminal domain anchored to the cell wall through the R domain of clumping factor A, showed that the Esp N-terminal region is sufficient to confer multicellular behavior through the formation of an extracellular amyloid-like material. These results suggest that the mechanism of amyloid-like aggregation to build the biofilm matrix might be widespread among BAP-like proteins. This amyloid-based mechanism may not only have strong relevance for bacteria lifestyle but could also contribute to the amyloid burden to which the human physiology is potentially exposed.}, } @article {pmid32220258, year = {2020}, author = {Yu, S and Jiang, B and Jia, C and Wu, H and Shen, J and Hu, X and Xie, Z}, title = {Investigation of biofilm production and its association with genetic and phenotypic characteristics of OM (osteomyelitis) and non-OM orthopedic Staphylococcus aureus.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {19}, number = {1}, pages = {10}, pmid = {32220258}, issn = {1476-0711}, support = {BWS13C014//Key Project of the General Logistics Department of PLA/ ; 81672160//General Program of National Natural Foundation of China/ ; 31570127//General Program of National Natural Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects/growth & development ; Drug Resistance, Multiple, Bacterial/genetics ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Musculoskeletal Diseases/drug therapy/*microbiology ; Osteomyelitis/drug therapy/microbiology ; Phenotype ; *Staphylococcal Infections/drug therapy ; *Staphylococcus aureus/drug effects/genetics/isolation & purification ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Staphylococcus aureus is a primary pathogen of orthopedic infections. By mediating antimicrobial resistance, S. aureus biofilm plays an important role in the recalcitrance of orthopedic infections, especially for the intractable osteomyelitis (OM). This study investigated the relationship between biofilm production and various genetic or phenotypic characteristics among orthopedic S. aureus strains.

METHODS: A total of 137 orthopedic S. aureus isolates were enrolled and divided into OM and non-OM groups. Biofilm production was evaluated using the crystal violet assay. Genetic and phenotypic characteristics including MRSA identification, MLST and spa typing, carriage of virulence genes, drug resistance, and patients' inflammatory responses indicators were characterized. The relationship between biofilm production and above-mentioned features was respectively analyzed among all isolates and compared between OM and non-OM isolates.

RESULTS: Biofilm production presented no significant difference between OM (including 9 MRSA isolates) and non-OM (including 21 MRSA isolates) strains. We found that ST88, t377 and ST630-MSSA-t377 strains produced very strong biofilms, while MLST types of ST15, ST25, ST398, ST5, ST59 and spa types of t002, t2325, t437 tended to produce weaker biofilms. Strains with the following profiles produced stronger biofilms: fib(+)-hlgv(+)-lukED(+)-sei(-)-sem(-)-seo(-) for all isolates, sei(-)-sem(-)-seo(-) for OM isolates, and cna (+)-fib (+)-hlgv (+)-lukED (+)-seb(-)-sed(-) for non-OM isolates. In addition, not any single drug resistance was found to be related to biofilm production. We also observed that, among OM patients, strains with stronger biofilms caused weaker inflammatory responses.

CONCLUSION: Some genetic or phenotypic characteristics of orthopedic strains were associated with biofilm production, and this association could be different among OM and non-OM strains. The results are of great significance for better understanding, evaluating and managing different kinds of biofilm-associated orthopedic infections, and provide potential targets for biofilm clearance.}, } @article {pmid32219018, year = {2020}, author = {Reamtong, O and Indrawattana, N and Rungruengkitkun, A and Thiangtrongjit, T and Duangurai, T and Chongsa-Nguan, M and Pumirat, P}, title = {Altered proteome of a Burkholderia pseudomallei mutant defective in short-chain dehydrogenase affects cell adhesion, biofilm formation and heat stress tolerance.}, journal = {PeerJ}, volume = {8}, number = {}, pages = {e8659}, pmid = {32219018}, issn = {2167-8359}, abstract = {Burkholderia pseudomallei is a Gram-negative bacillus that causes melioidosis and is recognized as an important public health problem in southeast Asia and northeast Australia. The treatment of B. pseudomallei infection is hampered by resistance to a wide range of antimicrobial agents and no vaccine is currently available. At present, the underlying mechanisms of B. pseudomallei pathogenesis are poorly understood. In our previous study, we reported that a B. pseudomallei short-chain dehydrogenase (SDO; BPSS2242) mutant constructed by deletion mutagenesis showed reduced B. pseudomallei invasion and initial intracellular survival. This indicated that SDO is associated with the pathogenesis of melioidosis. In the present study, the role of B. pseudomallei SDO was further investigated using the SDO deletion mutant by a proteomic approach. The protein profiles of the SDO mutant and wild-type K96243 were investigated through gel-based proteomic analysis. Quantitative intensity analysis of three individual cultures of the B. pseudomallei SDO mutant revealed significant down-regulation of five protein spots compared with the wild-type. Q-TOF MS/MS identified the protein spots as a glutamate/aspartate ABC transporter, prolyl-tRNA synthetase, Hsp70 family protein, quinone oxidoreductase and a putative carboxypeptidase. Functional assays were performed to investigate the role of these differentially expressed proteins in adhesion to host cells, biofilm induction and survival under heat stress conditions. The SDO deletion mutant showed a decreased ability to adhere to host cells. Moreover, biofilm formation and the survival rate of bacteria under heat stress conditions were also reduced in the mutant strain. Our findings provide insight into the role of SDO in the survival and pathogenesis of B. pseudomallei at the molecular level, which may be applied to the prevention and control of B. pseudomallei infection.}, } @article {pmid32216092, year = {2020}, author = {Casar, CP and Kruger, BR and Flynn, TM and Masterson, AL and Momper, LM and Osburn, MR}, title = {Mineral-hosted biofilm communities in the continental deep subsurface, Deep Mine Microbial Observatory, SD, USA.}, journal = {Geobiology}, volume = {18}, number = {4}, pages = {508-522}, doi = {10.1111/gbi.12391}, pmid = {32216092}, issn = {1472-4669}, mesh = {Biodiversity ; *Biofilms ; Earth, Planet ; Minerals ; }, abstract = {Deep subsurface biofilms are estimated to host the majority of prokaryotic life on Earth, yet fundamental aspects of their ecology remain unknown. An inherent difficulty in studying subsurface biofilms is that of sample acquisition. While samples from marine and terrestrial deep subsurface fluids have revealed abundant and diverse microbial life, limited work has described the corresponding biofilms on rock fracture and pore space surfaces. The recently established Deep Mine Microbial Observatory (DeMMO) is a long-term monitoring network at which we can explore the ecological role of biofilms in fluid-filled fractures to depths of 1.5 km. We carried out in situ cultivation experiments with single minerals representative of DeMMO host rock to explore the ecological drivers of biodiversity and biomass in biofilm communities in the continental subsurface. Coupling cell densities to thermodynamic models of putative metabolic reactions with minerals suggests a metabolic relationship between biofilms and the minerals they colonize. Our findings indicate that minerals can significantly enhance biofilm cell densities and promote selective colonization by taxa putatively capable of extracellular electron transfer. In turn, minerals can drive significant differences in biodiversity between fluid and biofilm communities. Given our findings at DeMMO, we suggest that host rock mineralogy is an important ecological driver in deep continental biospheres.}, } @article {pmid32216024, year = {2020}, author = {Velichko, NS and Grinev, VS and Fedonenko, YP}, title = {Characterization of biopolymers produced by planktonic and biofilm cells of Herbaspirillum lusitanum P6-12.}, journal = {Journal of applied microbiology}, volume = {129}, number = {5}, pages = {1349-1363}, doi = {10.1111/jam.14647}, pmid = {32216024}, issn = {1365-2672}, mesh = {Bacterial Capsules/chemistry/metabolism ; *Biofilms/growth & development ; Biopolymers/*chemistry/metabolism ; Extracellular Polymeric Substance Matrix/chemistry/metabolism ; Glycoproteins/chemistry/metabolism ; Herbaspirillum/*chemistry/growth & development/metabolism/*physiology ; Lipopolysaccharides/chemistry/metabolism ; Polysaccharides, Bacterial/chemistry/metabolism ; }, abstract = {AIMS: The goal of this study was to characterize biopolymers from two modes of the Herbaspirillum lusitanum P6-12 growth: planktonic, in which cells are free swimming, and biofilm life style, in which the cells are sessile.

METHODS AND RESULTS: Differences in biopolymers composition from planktonic and biofilm cells of H. lusitanum strain P6-12 were analysed using Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulphate-polyacrylamide gel electrophoresis, gas-liquid chromatography and spectrophotometry. A high degree of polymer separation and purification was achieved by ultracentrifugation, and column chromatography allowed us to identify the chemical differences between biopolymers from biofilm and planktonic H. lusitanum. It was shown that planktonic cells of H. lusitanum P6-12 when cultivated in a liquid medium to the end of the exponential phase of growth, produced two high-molecular-weight glycoconjugates (were arbitrarily called CPS-I and CPS-II) of a lipopolysaccharide (LPS) nature and a lipid-polysacharide complex (were arbitrarily called EPS). The EPS, CPS-I, CPS-II had different monosaccharide and lipid compositions. The extracellular polymeric matrix (EPM) produced by the biofilm cells was mostly proteinaceous, with a small amount of carbohydrates (up to 3%). From the biofilm culture medium, a free extracellular polymeric substance (was arbitrarily called fEPS) was obtained that contained proteins and carbohydrates (up to 7%). The cells outside the biofilm had capsules containing high-molecular-weight glycoconjugate (was arbitrarily called CPSFBC) that consisted of carbohydrates (up to 10%), proteins (up to 16%) and lipids (up to 70%).

CONCLUSIONS: During biofilm formation, the bacteria secreted surface biopolymers that differed from those of the planktonic cells. The heterogeneity of the polysaccharide containing biopolymers of the H. lusitanum P6-12 surface is probably conditioned by their different functions in plant colonization and formation of an efficient symbiosis, as well as in cell adaptation to existence in plant tissues.

The results of the study permit a better understanding of the physiological properties of the biopolymers, for example, in plant-microbe interactions.}, } @article {pmid32215705, year = {2020}, author = {Kaur, A and Capalash, N and Sharma, P}, title = {Expression of Meiothermus ruber luxS in E. coli alters the antibiotic susceptibility and biofilm formation.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {10}, pages = {4457-4469}, doi = {10.1007/s00253-020-10480-8}, pmid = {32215705}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/*genetics ; Drug Resistance, Microbial/*genetics ; Escherichia coli/*drug effects/*genetics/physiology ; Gene Expression Profiling ; Genetic Complementation Test ; Membrane Transport Proteins/genetics ; Microbial Sensitivity Tests ; Quorum Sensing/drug effects ; }, abstract = {Quorum sensing (QS) and signal molecules used for interspecies communication are well defined in mesophiles, but there is still a plethora of microorganisms in which existence and mechanisms of QS need to be explored, thermophiles being among them. In silico analysis has revealed the presence of autoinducer-2 (AI-2) class of QS signaling molecules in thermophiles, synthesized by LuxS (AI-2 synthase), though the functions of this system are not known. In this study, LuxS of Meiothermus ruber was used for understanding the mechanism and functions of AI-2 based QS among thermophilic bacteria. The luxS gene of M. ruber was expressed in luxS[-] deletion mutant of Escherichia coli. Complementation of luxS resulted in significant AI-2 activity, enhanced biofilm formation, and antibiotic susceptibility. Transcriptome analysis showed significant differential expression of 204 genes between the luxS-complemented and luxS[-] deletion mutant of E. coli. Majority of the genes regulated by luxS belonged to efflux pumps. This elucidation may contribute towards finding novel alternatives against incessant antibiotic resistance in bacteria.Key Points• Expression of luxS in luxS[-]E. coli resulted in increase in biofilm index. • Reduction in the MIC of antibiotics was observed after complementation of luxS. • Downregulation of efflux pump genes was observed after complementation of luxS. • Transcriptome analysis showed that 204 genes were differentially regulated significantly.}, } @article {pmid32213553, year = {2020}, author = {Kırmusaoğlu, S and Kaşıkçı, H}, title = {Identification of ica-dependent biofilm production by Staphylococcus aureus clinical isolates and antibiofilm effects of ascorbic acid against biofilm production.}, journal = {Journal of clinical pathology}, volume = {73}, number = {5}, pages = {261-266}, doi = {10.1136/jclinpath-2019-206280}, pmid = {32213553}, issn = {1472-4146}, mesh = {Anti-Bacterial Agents/*pharmacology ; Ascorbic Acid/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects/growth & development ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {AIMS: Staphylococcus aureus (S. aureus) is a life-threatening pathogen with high morbidity and mortality rates which causes nosocomial and community-acquired infections. Biofilm, considered to be a common virulence factor for pathogens, plays a significant role in recurrent and untreatable infections. Biofilm formation of S. aureus is mediated by synthesis of either poly-N-acetylglucosamine in an ica-dependent manner or surface proteins in an ica-independent manner. In some cases treatment is impossible and recurrent. In this study, ica-dependent biofilm-producing S. aureus isolates were detected and the anti-biofilm effect of ascorbic acid against biofilm formation of isolates was investigated.

METHODS: A total of 21 methicillin-sensitive S. aureus (MSSA) clinical isolates stored in our bacterial stock were used to detect ica-dependent biofilm-producing MSSA isolates. The anti-biofilm study was undertaken with three ica-dependent biofilm-producing isolates (MSSA2-4) and ATCC 29213 (MSSA1). Biofilms and the anti-biofilm effect of ascorbic acid were detected using the microtitre plate (MtP) method. 16S-rRNA, nuc, icaA and icaD genes and expression levels of icaA and icaD of isolates were detected by RT-PCR.

RESULTS: The minimum inhibitory concentrations (MICs) of ascorbic acid prevented biofilm formation of MSSA1 and MSSA3. Also, 1/2 MIC of ascorbic acid prevented biofilm formation of MSSA3. It was observed that biofilm formation decreased with increased concentration. There was no significant increase in ica gene expression of MSSA1 and MSSA2. Expression of icaA and icaD of MSSA3 decreased 13% and 38%, respectively. Expression of icaA in MSSA4 decreased 12%.

CONCLUSION: The results of our study show that ascorbic acid can be used as an anti-biofilm agent to prevent biofilm formation of S. aureus and thus biofilm-related infections.}, } @article {pmid32211736, year = {2020}, author = {Qiao, Z and Yao, Y and Song, S and Yin, M and Yang, M and Yan, D and Yang, L and Luo, J}, title = {Gold nanorods with surface charge-switchable activities for enhanced photothermal killing of bacteria and eradication of biofilm.}, journal = {Journal of materials chemistry. B}, volume = {8}, number = {15}, pages = {3138-3149}, doi = {10.1039/d0tb00298d}, pmid = {32211736}, issn = {2050-7518}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/drug effects ; Escherichia coli/*drug effects ; Gold/chemistry/*pharmacology ; Hydrogen-Ion Concentration ; Infrared Rays ; Microbial Sensitivity Tests ; Molecular Structure ; Nanotubes/*chemistry ; Particle Size ; Photothermal Therapy ; Polymethacrylic Acids/chemistry/pharmacology ; Staphylococcus aureus/*drug effects ; Surface Properties ; }, abstract = {The increasing growth and severity of bacterial biofilm infections and the appearance of multidrug-resistant bacteria pose alarming threats to public healthcare systems, mainly due to their formidable tolerance to conventional antibiotics. Different from the antibacterial mechanisms of antibiotics, gold nanorods (AuNRs) disinfect microbes by local heating induced by near-infrared (NIR) light irradiation; thus, they are potential disinfection agents. In an attempt to increase the biocompatibility and antibacterial activities of AuNRs against organisms in both planktonic and biofilm phenotypes, polymethacrylate with pendant carboxyl betaine groups was decorated on AuNRs (PCB-AuNRs) to afford AuNRs with pH-induced surface charge-transformable activities. The zwitterion-modified AuNRs demonstrated a pH-responsive transition from negative charge to positive charge; this confers the AuNRs with a change in functionality from biocompatible zwitterionic nanocomposites in healthy tissues (pH = ∼7.4) to enhanced antimicrobial cationic nanocomposites at acidic bacterial infection sites (pH = ∼5.5). AuNRs coated by polymethacrylate with pendant mPEG (PPEGMA-AuNRs) without surface charge transition activities were used for comparison. PCB-AuNRs presented better antimicrobial activity against Gram-negative bacteria (E. coli), Gram-positive bacteria (S. aureus) and their drug-resistant strains (MRSA and EBSL E. coli) than PPEGMA-AuNRs as a result of their pH-responsive surface charge transition activities. Moreover, PCB-AuNRs demonstrated deeper penetration into mature biofilms and better biofilm elimination activities than their non-surface charge-transformable counterparts. The results indicate that the designed zwitterion-coated AuNRs are a promising antibacterial agent for fighting bacterial infections.}, } @article {pmid32210924, year = {2020}, author = {Zhong, X and Wu, Q and Zhang, J and Ma, Z and Wang, J and Nie, X and Ding, Y and Xue, L and Chen, M and Wu, S and Wei, X and Zhang, Y}, title = {Campylobacter jejuni Biofilm Formation Under Aerobic Conditions and Inhibition by ZnO Nanoparticles.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {207}, pmid = {32210924}, issn = {1664-302X}, abstract = {Campylobacter jejuni is a major foodborne pathogen worldwide. As it forms biofilms, it can become a persistent contaminant in the food and pharmaceutical industries. In this study, it was demonstrated that C. jejuni could make more biofilm in aerobic conditions than in microaerobic conditions, and only 13.9% C. jejuni entered coccus (a VBNC state) under microaerobic conditions; however, the rate increased to 95.5% under aerobic conditions. C. jejuni could form more biofilm in mixed culture with Escherichia coli or Pseudomonas aeruginosa than in pure culture. Scanning electron microscope results showed that C. jejuni retained its normal spiral shape under aerobic conditions for 48 h by forming crosslinks with the aerobic and facultative anaerobic bacteria. Additionally, culture medium containing 0.5 mg/ml ZnO nanoparticles inhibited biofilm formation. Our results provide information on a new approach to controlling contamination via C. jejuni.}, } @article {pmid32210139, year = {2020}, author = {Topa, SH and Palombo, EA and Kingshott, P and Blackall, LL}, title = {Activity of Cinnamaldehyde on Quorum Sensing and Biofilm Susceptibility to Antibiotics in Pseudomonas aeruginosa.}, journal = {Microorganisms}, volume = {8}, number = {3}, pages = {}, pmid = {32210139}, issn = {2076-2607}, abstract = {Quorum sensing (QS) plays an important role during infection for the opportunistic human pathogen Pseudomonas aeruginosa. Quorum sensing inhibition (QSI) can disrupt this initial event of infection without killing bacterial cells, and thus QS inhibitors have been suggested as novel approaches for anti-infective therapy. Cinnamaldehyde (CAD) is a P. aeruginosa biofilm inhibitor and disperser of preformed biofilms. In this study, the combined use of CAD and colistin (COL) revealed a synergistic activity, but this was not the case for CAD combined with carbenicillin, tobramycin (TOB), or erythromycin in checkerboard assays for P. aeruginosa. CAD demonstrated QSI activity by repression of the expression of lasB, rhlA and pqsA in GFP reporter assays. Approximately 70% reduction in GFP production was observed with the highest CAD concentration tested in all the QS reporter strains. TOB also showed strong QSI when combined with CAD in reporter assays. Combination treatments revealed an additive activity of CAD with COL and TOB in biofilm inhibition (75.2% and 83.9%, respectively) and preformed biofilm dispersion (~90% for both) when compared to the individual treatments. Therefore, a proposed method to mitigate P. aeruginosa infection is a combination therapy of CAD with COL or CAD with TOB as alternatives to current individual drug therapies.}, } @article {pmid32209391, year = {2020}, author = {Emad, F and Khalafalah, AK and El Sayed, MA and Mohamed, AH and Stadler, M and Helaly, SE}, title = {Three new polyacetylene glycosides (PAGs) from the aerial part of Launaea capitata (Asteraceae) with anti-biofilm activity against Staphylococcus aureus.}, journal = {Fitoterapia}, volume = {143}, number = {}, pages = {104548}, doi = {10.1016/j.fitote.2020.104548}, pmid = {32209391}, issn = {1873-6971}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Asteraceae/*chemistry ; Biofilms/*drug effects ; Egypt ; Glucosides ; Glycosides/isolation & purification/*pharmacology ; Luteolin ; Microbial Sensitivity Tests ; Molecular Structure ; Phytochemicals/isolation & purification/pharmacology ; Plant Components, Aerial/chemistry ; Polyacetylene Polymer/isolation & purification/*pharmacology ; Staphylococcus aureus/drug effects ; }, abstract = {Four polyacetylenic glycosides, three of which are new, together with two known flavonoids were isolated from the methanol extract of the aerial parts of Launaea capitate, designated bidensyneoside A1 (1), 6´-O-acetyl-bidensyneoside A1 (2), bidensyneoside E (3), bidensyneoside F (4), luteolin (5) and luteolin-7-glucoside (6) also known as cynaroside. Their structures were elucidated by comprehensive analysis of 1D, 2D-NMR and HR-MS data. The absolute configuration of the bidensyneosides was determined by Mosher ester analysis and the optical rotation values. The isolated compounds were tested against biofilm formation of Staphylococcus aureus as well as against several pathogens including Gram-positive bacteria, Gram-negative bacteria, fungi and yeasts. Furthermore, they were tested for their cytotoxicity against two cancer cell lines L929 and KB-3-1. Compound 4 showed moderate inhibition of S. aureus biofilm formation with 30% and 25% at 256 and 128 μg/mL, respectively, while compounds 1 and 5 showed weak inhibition with 20% at 256 μg/mL. Compound 5 showed moderate cytotoxicity against both cell lines L929 and KB-3-1, with IC50 values of 18 μg/mL.}, } @article {pmid32209050, year = {2020}, author = {Martinez, S and Garcia, JG and Williams, R and Elmassry, M and West, A and Hamood, A and Hurtado, D and Gudenkauf, B and Ventolini, G and Schlabritz-Loutsevitch, N}, title = {Lactobacilli spp.: real-time evaluation of biofilm growth.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {64}, pmid = {32209050}, issn = {1471-2180}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Electric Impedance ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; Lactobacillus/genetics/*physiology ; Sequence Analysis, RNA ; Species Specificity ; Time Factors ; Video Recording ; Exome Sequencing ; }, abstract = {BACKGROUND: Biofilm is a fundamental bacterial survival mode which proceeds through three main generalized phases: adhesion, maturation, and dispersion. Lactobacilli spp. (LB) are critical components of gut and reproductive health and are widely used probiotics. Evaluation of time-dependent mechanisms of biofilm formation is important for understanding of host-microbial interaction and development of therapeutic interventions. Time-dependent LB biofilm growth was studied in two systems: large biofilm output in continuous flow system (microfermenter (M), Institute Pasteur, France) and electrical impedance-based real time label-free cell analyzer (C) (xCELLigence, ACEA Bioscience Inc., San Diego, CA). L. plantarum biofilm growth in M system was video-recorded, followed by analyses using IMARIS software (Bitplane, Oxford Instrument Company, Concord, MA, USA). Additionally, whole genome expression and analyses of attached (A) and dispersed (D) biofilm phases at 24 and 48 h were performed.

RESULTS: The dynamic of biofilm growth of L. plantarum was similar in both systems except for D phases. Comparison of the transcriptome of A and D phases revealed, that 121 transcripts differ between two phases at 24 h. and 35 transcripts - at 48 h. of M growth. The main pathways, down-regulated in A compared to D phases after 24 h. were transcriptional regulation, purine nucleotide biosynthesis, and L-aspartate biosynthesis, and the upregulated pathways were fatty acid and phospholipid metabolism as well as ABC transporters and purine nucleotide biosynthesis. Four LB species differed in the duration and amplitude of attachment phases, while growth phases were similar.

CONCLUSION: LB spp. biofilm growth and propagation area dynamic, time-dependent processes with species-specific and time specific characteristics. The dynamic of LB biofilm growth agrees with published pathophysiological data and points out that real time evaluation is an important tool in understanding growth of microbial communities.}, } @article {pmid32208520, year = {2020}, author = {Mai, Q and Yang, G and Cao, J and Zhang, X and Zhuang, L}, title = {Stratified microbial structure and activity within anode biofilm during electrochemically assisted brewery wastewater treatment.}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {7}, pages = {2023-2031}, doi = {10.1002/bit.27342}, pmid = {32208520}, issn = {1097-0290}, support = {//National Program for Support of Top-Notch Young Professionals/International ; 2017TX04Z351//Guangdong Special Support Program/International ; 201903010071//Science and Technology Program of Guangzhou, China/International ; }, mesh = {*Bioelectric Energy Sources/microbiology ; *Biofilms ; Electrodes ; Ethanol/*isolation & purification ; Geobacter/*physiology ; Microbiota ; Wastewater/*analysis/microbiology ; *Water Purification/instrumentation/methods ; }, abstract = {In a bioelectrochemical system (BES), microbial community of anode biofilm is crucial to BES performance. In this study, the stratified pattern of community structure and activity of an anode-respiring biofilm in a BES fueled with brewery wastewater was investigated over time. The anode biofilm exhibited a superior performance in the removal of ethanol to that of an open-circuit system. The electrical current density reached a high level of 0.55mA/cm[2] with a Coulombic efficiency of 71.4%, but decreased to 0.18mA/cm[2] in the late stage of operation. A mature biofilm developed a more active outer layer covering a less active inner core, although the activities of the outer and inner layers of biofilm were similar in the early stage. More Geobacter spp., typical exoelectrogens, were enriched in the outer layer than in the inner layer of biofilm in the early stage, while more Geobacter spp. were distributed in the inner layer than in the outer layer in the late stage. The inactive and Geobacter-occupied inner layer of biofilm might be responsible for the decreased electricity generation from wastewater in the late stage of operation. This study provides better understanding of the effect of anode biofilm structure on BES performance.}, } @article {pmid32208257, year = {2020}, author = {Zhang, H and Bi, Z and Pan, Y and Huang, Y and Li, DP and Shan, J}, title = {Enhanced phosphorus storage in suspended biofilm by increasing dissolved oxygen.}, journal = {The Science of the total environment}, volume = {722}, number = {}, pages = {137876}, doi = {10.1016/j.scitotenv.2020.137876}, pmid = {32208257}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors ; Oxygen ; Phosphorus ; Waste Disposal, Fluid ; }, abstract = {The phosphorus recovery efficiency in PAOs-biofilm system is so far limited to stimulating phosphorus release by adding concentrated organic carbon solution during the anaerobic stage. In present study, a PAOs-biofilm sequence batch reactor (BSBR) were operated to investigate whether increase of the phosphorus storage content via DO control can stimulate the release in the biofilm. During the operation of BSBR for 160 days, the phosphorus content in biofilm (Pbiofilm) was doubled via increasing dissolved oxygen (DO) from 4 to 6 mg/L. With the COD of 200 mg/L in the anaerobic phase, the phosphorus release was enhaced, resulting in an significant increase of phosphorus concentration from 94.85 to 179.5 mg/L in recirculated solution. Batch tests further clarified explicitly the increase of Pbiofilm stimulated a phosphorus release rate but this must be balanced since high Pbiofilm reduced the phosphorus removal capacity of the biofilm. With analysis of P[31]-NMR, Ortho-P and Poly-P were the main phosphorus species stored in biofilm. The microbial cell played a more important role than EPS in phosphorus storage. The dominant phylum in the master reactor was Proteobacteria with an abundance of 64.4%, in which the Rhodocyclaceae was the dominant PAOs with an abundance of 10.1%. The outcome of this study elucidated that increase of phosphorus storage via DO control which facilitated more efficient phosphorus release with much lower organic carbon source consumption during the enrichment of phosphorus. Meanwhile, we provided a new perspective for the recovery of phosphorus in future wastewater treatment plants.}, } @article {pmid32207926, year = {2020}, author = {Kastl, A and Bogler, A and Spinnler, M and Sattelmayer, T and Be'er, A and Bar-Zeev, E}, title = {Impact of Hydrodynamics on the First Stages of Biofilm Formation in Forward Osmosis with Spacers.}, journal = {Environmental science & technology}, volume = {54}, number = {8}, pages = {5279-5287}, doi = {10.1021/acs.est.0c00380}, pmid = {32207926}, issn = {1520-5851}, mesh = {Biofilms ; *Biofouling ; Hydrodynamics ; Membranes, Artificial ; Osmosis ; *Water Purification ; }, abstract = {Initial deposition of bacteria is a critical stage during biofilm formation and biofouling development in membrane systems used in the water industry. However, the effects of hydrodynamic conditions on spatiotemporal deposition patterns of bacteria during the initial stages of biofilm formation remain unclear. Large field epifluorescence microscopy enabled in situ and real-time tracking of Bacillus subtilis in a forward osmosis system with spacers during the first 4 h of biofilm formation. This study quantitatively compares the spatiotemporal deposition patterns between different hydrodynamic conditions: high and low permeate water flux (6 or 30 L m[-2] h[-1]) as well as high and low crossflow velocity (1 or 14 cm s[-1]). Low crossflow velocity and high permeate water flux maximized bacterial attachment to the membrane surface, which was 60 times greater (6 × 10[3] cells mm[-2]) than at high crossflow velocity and low permeate water flux (<100 cells mm[-2]). Imaging at 30 s intervals revealed three phases (i.e., lag, exponential, and linear) in the development of deposition over time. Quantification of spatial deposition patterns showed that an increase in the ratio of permeate water flux to crossflow velocity led to a homogeneous deposition, while a decrease had the opposite effect. The insights of this research indicate that an appropriate choice of hydrodynamic conditions can minimize bacteria accumulation prior to biofilm formation in new and cleaned FO membrane systems treating water of high fouling propensity.}, } @article {pmid32207608, year = {2020}, author = {Voss, M and Alessio, KO and Vianna Santos, RC and de Souza, ME and Clerici, DJ and Wagner, R and Cichoski, AJ and Costa, ABD and Helfer, GA and Machado, GS and Barbosa, JLV and Müller, EI and Barin, JS}, title = {Rapid, Noninvasive, and Nondestructive Method for Biofilm Imaging on Metallic Surfaces Using Active Thermography.}, journal = {Analytical chemistry}, volume = {92}, number = {8}, pages = {5682-5687}, doi = {10.1021/acs.analchem.9b05713}, pmid = {32207608}, issn = {1520-6882}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Food Microbiology ; Microbial Sensitivity Tests ; Peracetic Acid/pharmacology ; Pseudomonas aeruginosa/drug effects ; Stainless Steel/*chemistry ; Surface Properties ; *Thermography ; }, abstract = {A simple, rapid, low-cost method was proposed for the imaging of Pseudomonas aeruginosa biofilms on metallic surfaces using an infrared camera. Stainless steel coupons were cooled to generate a thermal gradient in relation to biofilm for active thermography (AT). Both cooling and image acquisition times were optimized and the images obtained with AT were compared with those from scanning electron microscopy. A free software (Thermofilm) was developed for image processing and the results were compared with the software ImageJ, with good agreement (from 87.7 to 103.8%). Images of coupons treated with sanitizer (peracetic acid) were obtained to show the applicability of the proposed method for biofilm studies. All analytical steps could be performed in 3 min in a noncontact, nondestructive, low-cost, portable, and easy-to-use way.}, } @article {pmid32204360, year = {2020}, author = {Liu, H and Liu, X and Ding, N}, title = {An Innovative in Situ Monitoring of Sulfate Reduction within a Wastewater Biofilm by H2S and SO4[2-] Microsensors.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {6}, pages = {}, pmid = {32204360}, issn = {1660-4601}, mesh = {*Biofilms ; Environmental Monitoring ; *Hydrogen Sulfide ; Oxidation-Reduction ; Sulfates ; *Wastewater ; }, abstract = {Microelectrodes can be used to obtain chemical profiles within biofilm microenvironments. For example, sulfate (SO4[2-]) and hydrogen sulfide (H2S) microelectrodes can be used to study sulfate reduction activity in this context. However, there is no SO4[2-] microelectrode available for studying sulfate reduction in biofilms. In this study, SO4[2-] and H2S microelectrodes were fabricated and applied in the measurement of a wastewater membrane-aerated biofilm (MAB) to investigate the in situ sulfate reduction activity. Both the SO4[2-] and H2S microelectrodes with a tip diameter of around 20 micrometers were successfully developed and displayed satisfying selectivity to SO4[2][-] and H2S, respectively. The Nernstian slopes of calibration curves of the fabricated SO4[2-] electrodes were close to -28.1 mV/decade, and the R[2] values were greater than 98%. Within the selected concentration range from 10[-][5] M (0.96 mg/L) to 10[-][2] M (960 mg/L), the response of the SO4[2-] microelectrode was log-linearly related to its concentration. The successfully fabricated SO4[2-] microelectrode was combined with the existing H2S microelectrode and applied on an environmental wastewater biofilm sample to investigate the sulfate reduction activity within it. The H2S and SO4[2-] microelectrodes showed stable responses and good performance, and the decrease of SO4[2-] with an accompanying increased of H2S within the biofilm indicated the in situ sulfate reduction activity. The application of combined SO4[2-] and H2S microelectrodes in wastewater biofilms could amend the current understanding of sulfate reduction and sulfur oxidation within environmental biofilms based on only H2S microelectrodes.}, } @article {pmid32201415, year = {2020}, author = {Kamagata, Y}, title = {Recent Biofilm Studies Open a New Door in Microbial Ecology.}, journal = {Microbes and environments}, volume = {35}, number = {1}, pages = {}, pmid = {32201415}, issn = {1347-4405}, mesh = {*Biofilms ; *Ecology ; Environmental Pollutants ; Japan ; Research/*statistics & numerical data ; }, } @article {pmid32199161, year = {2020}, author = {Lu, Z and Li, D and Jiang, L and Chen, G and Li, K and Liu, G}, title = {Characterizing the biofilm stoichiometry and kinetics on the media in situ based on pulse-flow respirometer coupling with a new breathing reactor.}, journal = {Chemosphere}, volume = {252}, number = {}, pages = {126378}, doi = {10.1016/j.chemosphere.2020.126378}, pmid = {32199161}, issn = {1879-1298}, mesh = {*Biofilms ; Biomass ; *Bioreactors ; Heterotrophic Processes ; Kinetics ; Sewage/chemistry ; Waste Disposal, Fluid/*methods ; Wastewater ; }, abstract = {Biofilm based systems and the hybrid between activated sludge and biofilms have been popularly applied for wastewater treatment. Unlike the suspended biomass, the biofilm concentration and kinetics on the media cannot be easily measured. In this study, a novel and easy-to-use approach has been developed based on pulse-flow respirometer to characterize the biofilm stoichiometry and kinetics in situ. With the new designed breathing reactor, the mutual interference between the magnetic stirring and biofilm media that happened in the conventional breathing reactor was solved. Moreover, Microsoft Excel based programs had been developed to fit the oxygen uptake rate curves with dynamic nonlinear regression. With this new approach, the yield coefficient, maximum oxidation capacity, and half-saturation constant of substrate for the heterotrophic biofilms in a fix bed reactor were determined to be 0.46 g-VSS/g-COD, 67.0 mg-COD/(h·L-media), and 4.4 mg-COD/L, respectively. Those parameters for biofilm ammonia oxidizers from a moving bed biofilm reactor were determined to be 0.17 g-VSS/g-N, 18.6 mg-N/(h·L-media), and 1.2 mg-N/L, respectively, and they were 0.11 g-VSS/g-N, 20.9 mg-N/(h·L-media), and 0.98 mg-N/L for nitrite oxidizers in the same biofilms. This study also found that the maximum specific substrate utilization rate for detached biofilms increased by 3.2 times, indicating that maintaining biofilm integrity was very important in the kinetic tests. Using this approach, the biofilm kinetics on the media can be regularly measured for treatment optimization.}, } @article {pmid32198447, year = {2020}, author = {Muthamil, S and Prasath, KG and Priya, A and Precilla, P and Pandian, SK}, title = {Global proteomic analysis deciphers the mechanism of action of plant derived oleic acid against Candida albicans virulence and biofilm formation.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {5113}, pmid = {32198447}, issn = {2045-2322}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/genetics ; Candidiasis/*drug therapy ; Drug Resistance, Fungal/genetics ; Fungal Proteins/analysis/genetics ; Humans ; Microbial Sensitivity Tests ; Mucous Membrane/microbiology ; Murraya/metabolism ; Oleic Acid/*pharmacology ; Oxidative Stress/drug effects ; Proteomics ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Virulence/drug effects ; }, abstract = {Candida albicans is a commensal fungus in humans, mostly found on the mucosal surfaces of the mouth, gut, vagina and skin. Incidence of ever increasing invasive candidiasis in immunocompromised patients, alarming occurrence of antifungal resistance and insufficient diagnostic methods demand more focused research into C. albicans pathogenicity. Consequently, in the present study, oleic acid from Murraya koenigii was shown to have the efficacy to inhibit biofilm formation and virulence of Candida spp. Results of in vitro virulence assays and gene expression analysis, impelled to study the protein targets which are involved in the molecular pathways of C. albicans pathogenicity. Proteomic studies of differentially expressed proteins reveals that oleic acid induces oxidative stress responses and mainly targets the proteins involved in glucose metabolism, ergosterol biosynthesis, lipase production, iron homeostasis and amino acid biosynthesis. The current study emphasizes anti-virulent potential of oleic acid which can be used as a therapeutic agent to treat Candida infections.}, } @article {pmid32196364, year = {2022}, author = {Peruč, D and Tićac, B and Broznić, D and Maglica, Ž and Šarolić, M and Gobin, I}, title = {Juniperus communis essential oil limit the biofilm formation of Mycobacterium avium and Mycobacterium intracellulare on polystyrene in a temperature-dependent manner.}, journal = {International journal of environmental health research}, volume = {32}, number = {1}, pages = {141-154}, doi = {10.1080/09603123.2020.1741519}, pmid = {32196364}, issn = {1369-1619}, mesh = {Biofilms ; *Juniperus ; Mycobacterium avium ; Mycobacterium avium Complex ; *Oils, Volatile/pharmacology ; Polystyrenes ; Temperature ; }, abstract = {Formation of biofilms allows bacterial cells to survive in adverse environments. Nontuberculous mycobacteria are ubiquitous in aqueous environments, where they adhere to surfaces and create a biofilm. This has led to the emergence of healthcare-associated infections and the use of biomaterials in medicine. Essential oils (EO) are substances of natural origin whose effect on microorganisms has been the subject of numerous studies. Here, we investigated the effect of Juniperus communis EO on nontuberculous mycobacteria and their early and mature biofilm formation in sterilised tap water. The combination of Juniperus communis EO and increasing ambient temperature showed a synergistic effect on the reduction of biofilm formation of Mycobacterium avium and Mycobacterium intracellulare on a polystyrene surface. A significant antibiofilm effect of Juniperus communis EO was also found at subinhibitory concentrations, suggesting a potential role for it as an alternative disinfectant of natural water.}, } @article {pmid32196074, year = {2020}, author = {Alhede, M and Alhede, M and Qvortrup, K and Kragh, KN and Jensen, PØ and Stewart, PS and Bjarnsholt, T}, title = {The origin of extracellular DNA in bacterial biofilm infections in vivo.}, journal = {Pathogens and disease}, volume = {78}, number = {2}, pages = {}, pmid = {32196074}, issn = {2049-632X}, mesh = {Animals ; *Biofilms ; DNA, Bacterial/*metabolism ; Extracellular Traps/*metabolism ; Histones/metabolism ; Humans ; Mice ; Neutrophils/physiology/ultrastructure ; Pseudomonas Infections/immunology/metabolism/microbiology ; Pseudomonas aeruginosa/physiology ; }, abstract = {Extracellular DNA (eDNA) plays an important role in both the aggregation of bacteria and in the interaction of the resulting biofilms with polymorphonuclear leukocytes (PMNs) during an inflammatory response. Here, transmission electron and confocal scanning laser microscopy were used to examine the interaction between biofilms of Pseudomonas aeruginosa and PMNs in a murine implant model and in lung tissue from chronically infected cystic fibrosis patients. PNA FISH, DNA staining, labeling of PMN DNA with a thymidine analogue and immunohistochemistry were applied to localize bacteria, eDNA, PMN-derived eDNA, PMN-derived histone H3 (H3), neutrophil elastase (NE) and citrullinated H3 (citH3). Host-derived eDNA was observed surrounding bacterial biofilms but not within the biofilms. H3 localized to the lining of biofilms while NE was found throughout biofilms. CitH3, a marker for neutrophil extracellular traps (NETs) was detected only sporadically indicating that most host-derived eDNA in vivo was not a result of NETosis. Together these observations show that, in these in vivo biofilm infections with P. aeruginosa, the majority of eDNA is found external to the biofilm and derives from the host.}, } @article {pmid32195889, year = {2020}, author = {Ferlic, PW and Liebensteiner, M and Nogler, M and Weinberg, AM and Kühn, KD and Coraça-Huber, D}, title = {Increased Staphylococcus aureus Biofilm Formation on Biodegradable Poly(3-Hydroxybutyrate)-Implants Compared with Conventional Orthopedic Implants: An In Vitro Analysis.}, journal = {Journal of orthopaedic trauma}, volume = {34}, number = {4}, pages = {210-215}, doi = {10.1097/BOT.0000000000001674}, pmid = {32195889}, issn = {1531-2291}, mesh = {3-Hydroxybutyric Acid ; Biofilms ; Humans ; Hydroxybutyrates ; Polyesters ; Prohibitins ; *Staphylococcal Infections ; *Staphylococcus aureus ; Titanium ; }, abstract = {OBJECTIVE: To compare the biofilm formation on a biodegradable material, poly(3-hydroxybutyrate) (PHB), with that on conventional titanium (Ti) and steel (St) implant material.

METHODS: Pins made of the different materials were incubated in Müller-Hinton broth inoculated with 2 × 10 colony-forming units (CFU)·mL of Staphylococcus aureus for 2 and 7 days and then sonicated for the disruption of the biofilms. CFU were counted to quantify the number of bacteria in the biofilm, and the cell proliferation assay 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H- tetrazolium-5-carboxanilid salt was used to evaluate their metabolic activity. Scanning electron microscopy visualized the structure of the biofilm.

RESULTS: We found a significantly higher metabolic activity and CFU count in the biofilm of PHB pins compared with St and Ti pins (analysis of variance, P < 0.0001). Scanning electron microscopy revealed structured biofilms on PHB pins already after 2 days of incubation, which was not observed on the other tested implants.

CONCLUSION: PHB implants seem to provide an environment that advantages the formation of biofilms of S. aureus, a common pathogen in implant-related infections. The amount of biofilm is higher on PHB implant compared with conventionally used orthopedic titanium and steel implants. To overcome the potential risk of surgical site infections linked to the clinical use of PHB implants, possible modifications of the material, increasing its antibacterial properties, need to be further investigated.}, } @article {pmid32195387, year = {2020}, author = {Tosato, MG and Schilardi, P and Lorenzo de Mele, MF and Thomas, AH and Lorente, C and Miñán, A}, title = {Synergistic effect of carboxypterin and methylene blue applied to antimicrobial photodynamic therapy against mature biofilm of Klebsiella pneumoniae.}, journal = {Heliyon}, volume = {6}, number = {3}, pages = {e03522}, pmid = {32195387}, issn = {2405-8440}, abstract = {The control of multidrug-resistant (MDR) bacteria is a growing public health problem, and new strategies are urgently needed for the control of the infections caused by these microorganisms. Notoriously, some MDR microorganisms generate complex structures or biofilms, which adhere to surfaces and confer extraordinary resistance properties that are fundamental challenges to control infections. One of the promising strategies for the control of MDR bacteria is antimicrobial photodynamic therapy (aPDT), which takes advantage of suitable photosensitizers (PS), oxygen and radiation to eradicate microorganisms by the generation of highly reactive species, including reactive oxygen species (ROS) that cause cytotoxic damage and cell death. Habitual aPDT treatments use only methylene blue (MB), but MDR microorganism eradication is not completely achieved. The key result of this study revealed that a combination of two known PSs, 6-carboxypterin (Cap, 100 μM) and MB (2.5-10 μM) exposed to ultraviolet and visible radiation, presents a synergistic effect on the eradication of a MDR Klebsiella pneumoniae strain. Similar effect was observed when the treatment was performed either with planktonic or biofilm growing cells. Moreover, it was found that after treatment the killing action continues in the absence of irradiation leading to the eradication of the microorganisms growing in biofilm. Therefore, the combined aPDT represents a promising strategy for the management of clinical contact surfaces, disinfection of surgical instruments, biofouling and even antimicrobial wastewater treatment.}, } @article {pmid32195120, year = {2020}, author = {Rodriguez-Nava, G and Mohamed, A and Yanez-Bello, MA and Trelles-Garcia, DP}, title = {Advances in medicine and positive natural selection: Prosthetic valve endocarditis due to biofilm producer Micrococcus luteus.}, journal = {IDCases}, volume = {20}, number = {}, pages = {e00743}, pmid = {32195120}, issn = {2214-2509}, abstract = {Over the past years there has been a considerable increase in the use of aortic bioprostheses for treating aortic valve disease. With the increasing use of implanted medical devices, the incidence of prosthetic valve endocarditis has also increased. This is accompanied by a shift in the microbiology of infectious endocarditis. Micrococcus species are usually regarded as contaminants from skin and mucous membranes that rarely cause infectious diseases, however, they have the capacity to create biofilms from prosthetic materials and hence, to cause disease. We report the case of a 54-year-old woman who developed native valve infective endocarditis due to Micrococcus luteus. To our knowledge, only 18 cases of M. luteus prosthetic valve endocarditis have been described, none in the English literature.}, } @article {pmid32193579, year = {2020}, author = {Gutiérrez-Almada, K and González-Acosta, B and Borges-Souza, JM and Aguila-Ramírez, RN}, title = {Marine bacteria associated with shallow hydrothermal systems in the Gulf of California with the capacity to produce biofilm inhibiting compounds.}, journal = {Archives of microbiology}, volume = {202}, number = {6}, pages = {1477-1488}, pmid = {32193579}, issn = {1432-072X}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Aeromonas caviae/drug effects ; Anti-Bacterial Agents/*metabolism ; Antibiosis/*physiology ; Bacillus/drug effects ; Biofilms/*growth & development ; Brevibacillus/drug effects ; Chromobacterium/isolation & purification/*metabolism/physiology ; Hydrothermal Vents/*microbiology ; Mexico ; Pseudomonas aeruginosa/drug effects ; Quorum Sensing/physiology ; Vibrio alginolyticus/drug effects ; }, abstract = {Shallow hydrothermal systems are extreme environments. The sediments and fluids emitted from the vents present unusual physical and chemical conditions compared to other marine areas, which promotes unique biodiversity that has been of great interest for biotechnology for some years. In this work, a bioprospective study was carried out to evaluate the capacity of bacteria associated with shallow hydrothermal vents to produce biofilm-inhibiting compounds. Degradation assays of N-acyl homoserine lactone (AHL) autoinducers (C6HSL) involved in the quorum sensing process were carried out on 161 strains of bacteria isolated from three shallow hydrothermal systems located in Baja California Sur (BCS), Mexico. The biosensor Chromobacterium violaceum CV026 was used. Twenty-three strains showed activity, and organic extracts were obtained with ethyl acetate. The potential of the extracts to inhibit the formation of biofilms was tested against two human pathogenic strains (Pseudomonas aeruginosa PAO1 and Aeromonas caviae ScH3), a shrimp pathogen (Vibrio parahaemolyticus M8), and two marine strains identified as producing biofilms on submerged surfaces (Virgibacillus sp C29 and Vibrio alginolyticus C96). The results showed that Vibrio alginolyticus and Brevibacillus thermoruber, as well as some thermotolerant strains (mostly Bacillus), produce compounds that inhibit bacterial biofilms (B. licheniformis, B. paralicheniformis, B. firmus, B. oceanizedimenis, B. aerius and B. sonorensis).}, } @article {pmid32193350, year = {2020}, author = {Fei, C and Mao, S and Yan, J and Alert, R and Stone, HA and Bassler, BL and Wingreen, NS and Košmrlj, A}, title = {Nonuniform growth and surface friction determine bacterial biofilm morphology on soft substrates.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {14}, pages = {7622-7632}, pmid = {32193350}, issn = {1091-6490}, support = {R01 GM082938/GM/NIGMS NIH HHS/United States ; R21 AI146223/AI/NIAID NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; R21 AI114223/AI/NIAID NIH HHS/United States ; }, mesh = {Agar/*pharmacology ; Anisotropy ; Biofilms/*growth & development ; Biomechanical Phenomena ; Friction ; Stress, Mechanical ; Surface Properties ; Vibrio cholerae/*physiology ; }, abstract = {During development, organisms acquire three-dimensional (3D) shapes with important physiological consequences. While basic mechanisms underlying morphogenesis are known in eukaryotes, it is often difficult to manipulate them in vivo. To circumvent this issue, here we present a study of developing Vibrio cholerae biofilms grown on agar substrates in which the spatiotemporal morphological patterns were altered by varying the agar concentration. Expanding biofilms are initially flat but later undergo a mechanical instability and become wrinkled. To gain mechanistic insights into this dynamic pattern-formation process, we developed a model that considers diffusion of nutrients and their uptake by bacteria, bacterial growth/biofilm matrix production, mechanical deformation of both the biofilm and the substrate, and the friction between them. Our model shows quantitative agreement with experimental measurements of biofilm expansion dynamics, and it accurately predicts two distinct spatiotemporal patterns observed in the experiments-the wrinkles initially appear either in the peripheral region and propagate inward (soft substrate/low friction) or in the central region and propagate outward (stiff substrate/high friction). Our results, which establish that nonuniform growth and friction are fundamental determinants of stress anisotropy and hence biofilm morphology, are broadly applicable to bacterial biofilms with similar morphologies and also provide insight into how other bacterial biofilms form distinct wrinkle patterns. We discuss the implications of forming undulated biofilm morphologies, which may enhance the availability of nutrients and signaling molecules and serve as a "bet hedging" strategy.}, } @article {pmid32192962, year = {2020}, author = {Jiang, H and Peng, Y and Li, X and Zhang, F and Wang, Z and Ren, S}, title = {Advanced nitrogen removal from mature landfill leachate via partial nitrification-Anammox biofilm reactor (PNABR) driven by high dissolved oxygen (DO): Protection mechanism of aerobic biofilm.}, journal = {Bioresource technology}, volume = {306}, number = {}, pages = {123119}, doi = {10.1016/j.biortech.2020.123119}, pmid = {32192962}, issn = {1873-2976}, abstract = {A novel partial nitrification-Anammox biofilm reactor (PNABR) operated under high dissolved oxygen (DO) with pre-anoxic - aerobic - anoxic operational mode was developed for efficient denitrogenation from mature landfill leachate. With DO concentration gradually increasing to 4.03 ± 0.03 mg/L, the ammonia oxidation rate (AOR) was enhanced to 25.8 mgNH4[+]-N/(L h), while nitrite oxidation bacteria (NOB) was inhibited effectively by alternating free ammonia (FA) and oxygen starvation. DO micro-distribution revealed that estimated 1900 μm of aerobic biofilm could protect anammox biofilm underneath from being inhibited by high DO. qPCR analysis further suggested that ammonia oxidation bacteria (AOB) abundance in whole biofilm was 6.12 × 10[9] gene copies/(g dry sludge), which was twice than found in the floc. Anammox bacteria accounted for 2.39% of total bacteria in whole biofilm, contributing 90.0% to nitrogen removal. Nitrogen removal rate (NRR) and nitrogen removal efficiency (NRE) finally reached 396.6 gN/(m[3] d) and 96.1%, respectively.}, } @article {pmid32192956, year = {2020}, author = {Swain, G and Sonwani, RK and Giri, BS and Singh, RS and Jaiswal, RP and Rai, BN}, title = {Collective removal of phenol and ammonia in a moving bed biofilm reactor using modified bio-carriers: Process optimization and kinetic study.}, journal = {Bioresource technology}, volume = {306}, number = {}, pages = {123177}, doi = {10.1016/j.biortech.2020.123177}, pmid = {32192956}, issn = {1873-2976}, abstract = {The performance of a moving bed biofilm reactor (MBBR) with bio-carriers made of polypropylene-polyurethane foam (PP-PUF) was evaluated for the collective removal of phenol and ammonia. Three independent variables, including pH (5.0-8.0), retention time (2.0-12.0 h), and airflow rate (0.8-3.5 L/min) were optimized using central composite design (CCD) of response surface methodology (RSM). The maximum removal of phenol and ammonia was obtained to be 92.6, and 91.8%, respectively, in addition to the removal of 72.3% in the chemical oxygen demand (COD) level at optimum conditions. First-order and second-order kinetic models were analyzed to evaluate the pollutants removal kinetics in a MBBR. Finally, a second-order model was found to be appropriate for predicting reaction kinetics. The values of second-order rate constants were obtained to be 2.35, 0.25, and 1.85 L[2]/gVSS gCOD h for phenol, COD, and ammonia removal, respectively.}, } @article {pmid32192922, year = {2020}, author = {Alibi, S and Ben Selma, W and Ramos-Vivas, J and Smach, MA and Touati, R and Boukadida, J and Navas, J and Ben Mansour, H}, title = {Anti-oxidant, antibacterial, anti-biofilm, and anti-quorum sensing activities of four essential oils against multidrug-resistant bacterial clinical isolates.}, journal = {Current research in translational medicine}, volume = {68}, number = {2}, pages = {59-66}, doi = {10.1016/j.retram.2020.01.001}, pmid = {32192922}, issn = {2452-3186}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Antioxidants/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biphenyl Compounds ; Cinnamomum zeylanicum/chemistry ; Disk Diffusion Antimicrobial Tests ; Drug Evaluation, Preclinical ; Drug Resistance, Multiple, Bacterial ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Indoles/metabolism ; Microbial Sensitivity Tests ; Oils, Volatile/isolation & purification/*pharmacology ; Origanum/chemistry ; Picrates ; Quorum Sensing/*drug effects ; Syzygium/chemistry ; Thymus Plant/chemistry ; }, abstract = {PURPOSE OF THE STUDY: Outbreaks of multidrug-resistant bacteria are increasingly reported at the clinical setting. The antimicrobial, anti-biofilm, anti-quorum sensing, and anti-oxidant activities of four essential oils extracted from Cinnamomum verum, Origanum majorana, Thymus vulgaris, and Eugenia caryophyllata against Gram-positive and Gram-negative multidrug-resistant bacteria were evaluated in vitro.

MATERIALS AND METHODS: This study was conducted on 105 multidrug resistant clinical strains. Inhibition diameter zone, minimum inhibitory concentration, and minimum bactericide concentration of the oils were determined using agar disc diffusion method and microdilution. The ability of the 4 essential oils to inhibit the production of bacterial biofilms was tested on polystyrene plates, as well as their inhibitory effect on the production of violacein by Chromobacterium violaceum CV026. The anti-oxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl scavenging method.

RESULTS: Essential oils of Cinnamomum verum, Thymus vulgaris and Eugenia caryophyllata showed an important antibacterial activity. The inhibition diameter zone was higher than 20 mm for 90.24 %, 85.71 % and 60.95 % of strains respectively. These essential oils have a remarkable anti-biofilm and anti-quorum sensing activities against almost all the species studied. Clove extract revealed the highest anti-oxidant activity (Pourcentage of inhibtion of DPPH = 90.3 %).

CONCLUSION: These results supported the use of the 4 essential oils as alternative or complementary agents to treat infections caused by multidrug-resistant bacteria, and to prevent biofilm formation and quorum sensing signaling. They might be used as a safe anti-oxidants instead of harmful artificial ones.}, } @article {pmid32192009, year = {2020}, author = {Tran, P and Enos, T and Luth, K and Hamood, A and Ray, C and Mitchell, K and Reid, TW}, title = {Organo-Selenium-Containing Polyester Bandage Inhibits Bacterial Biofilm Growth on the Bandage and in the Wound.}, journal = {Biomedicines}, volume = {8}, number = {3}, pages = {}, pmid = {32192009}, issn = {2227-9059}, support = {x//South Plains Foundation/ ; }, abstract = {The dressing material of a wound plays a key role since bacteria can live in the bandage and keep re-infecting the wound, thus a bandage is needed that blocks biofilm in the bandage. Using an in vivo wound biofilm model, we examined the effectiveness of an organo-selenium (OS)-coated polyester dressing to inhibit the growth of bacteria in a wound. Staphylococcus aureus (as well as MRSA, Methicillin resistant Staph aureus), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over 7 logs of inhibition (100%) was found for all the bacterial strains on the material of the OS-coated wound dressing and in the tissue under that dressing. Confocal laser scanning microscopy along with IVIS spectrum in vivo imaging confirmed the CFU results. Thus, the dressing acts as a reservoir for a biofilm, which causes wound infection. The same results were obtained after soaking the dressing in PBS at 37 °C for three months before use. These results suggest that an OS coating on polyester dressing is both effective and durable in blocking wound infection.}, } @article {pmid32190119, year = {2020}, author = {Liu, L and Yu, B and Sun, W and Liang, C and Ying, H and Zhou, S and Niu, H and Wang, Y and Liu, D and Chen, Y}, title = {Calcineurin signaling pathway influences Aspergillus niger biofilm formation by affecting hydrophobicity and cell wall integrity.}, journal = {Biotechnology for biofuels}, volume = {13}, number = {}, pages = {54}, pmid = {32190119}, issn = {1754-6834}, abstract = {BACKGROUND: Biofilms, as a kind of fixed-cell community, can greatly improve industrial fermentation efficiency in immobilized fermentation, but the regulation process is still unclear, which restricts their application. Ca[2+] was reported to be a key factor affecting biofilm formation. However, the effect of Ca[2+] on biofilm structure and microbiology was yet only studied in bacteria. How Ca[2+]-mediated calcineurin signaling pathway (CSP) alters biofilm formation in bacteria and fungi has rarely been reported. On this basis, we investigated the regulation of CSP on the formation of biofilm in Aspergillus niger.

RESULTS: Deletion of the key genes MidA, CchA, CrzA or CnaA in the CSP lowered the Ca[2+] concentration in the mycelium to a different extent, inhibited the formation of A. niger biofilm, reduced the hydrophobicity and adhesion of spores, destroyed the cell wall integrity of hyphae, and reduced the flocculation ability of hyphae. qRT-PCR results showed that the expression of spore hydrophobic protein RodA, galactosaminogalactan (GAG) biosynthesis genes (uge3, uge5, agd3, gtb3), and α-1,3-glucan biosynthesis genes (ags1, ags3) in the ∆MidA, ∆CchA, ∆CrzA, ∆CnaA strains were significantly down-regulated compared with those of the wild type (WT). In addition, the transcription levels of the chitin synthesis gene (chsB, chsD) and β-1,3-glucan synthesis gene (FksA) were consistent with the change in chitin and β-1,3-glucan contents in mutant strains.

CONCLUSION: These results indicated that CSP affected the hydrophobicity and adhesion of spores, the integrity of mycelial cell walls and flocculation by affecting Ca[2+] levels in mycelium, which in turn affected biofilm formation. This work provides a possible explanation for how CSP changes the formation of A. niger biofilm, and reveals a pathway for controlling biofilm formation in industrial immobilized fermentation.}, } @article {pmid32189340, year = {2020}, author = {Li, Y and Wang, Y and Chen, X and Jiang, W and Jiang, X and Zeng, Y and Li, X and Feng, Z and Luo, J and Zhang, L}, title = {Antimicrobial peptide GH12 as root canal irrigant inhibits biofilm and virulence of Enterococcus faecalis.}, journal = {International endodontic journal}, volume = {53}, number = {7}, pages = {948-961}, doi = {10.1111/iej.13296}, pmid = {32189340}, issn = {1365-2591}, support = {81771062//National Natural Science Foundation of China/ ; 2018101581//National Innovation and Entrepreneurship Training Program/ ; }, mesh = {Anti-Bacterial Agents/therapeutic use ; *Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Enterococcus faecalis ; *Root Canal Irrigants ; Virulence ; }, abstract = {AIM: The objectives of this laboratory-based study were to investigate the effects of GH12 on Enterococcus faecalis biofilm and virulence.

METHODOLOGY: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of GH12 against E. faecalis were first determined. A time-kill assay was further conducted. The effects of GH12 on the expression of virulence and stress genes in E. faecalis were evaluated by RT-qPCR. Crystal violet stain was used to investigate the effects of GH12 on E. faecalis biofilm formation and 1-day-old biofilm. Finally, an ex vivo tooth model contaminated with E. faecalis was used to evaluate the antimicrobial activity of GH12 as an irrigant by CFU counting, SEM and CLSM. One-way anova and Tukey's multiple comparisons test were used to compare the differences amongst groups (α = 0.05).

RESULTS: The MICs and MBCs of GH12 against E. faecalis were 8.0 ± 0.0 and 16.0 ± 0.0 mg L[-1] , respectively, and GH12 at 32.0 mg L[-1] reduced the bacterial numbers by more than 99.9% within 1 min. Various virulence genes (efaA, esp and gelE) and stress genes (dnaK, groEL, ctsR and clpPBCEX) in E. faecalis were significantly downregulated by GH12 at sub-MIC levels (P < 0.05). Additionally, both E. faecalis biofilm formation and the biomass of 1-day-old E. faecalis biofilm were significantly reduced by GH12 (P < 0.05). Elimination of E. faecalis in biofilms from root canal walls was achieved through irrigation with 64.0 mg L[-1] GH12 for 30 min. CLSM analysis revealed that GH12 at 64.0 mg L[-1] was most effective in eliminating bacteria within dentinal tubules (P < 0.05).

CONCLUSION: In a laboratory setting, and when used as an irrigant, GH12 suppressed E. faecalis, downregulated specific virulence and stress-associated genes, eliminated intracanal E. faecalis protected by biofilms and killed bacteria in dentinal tubules. These results emphasize the need for preclinical and clinical studies to explore the potential of GH12 as an antimicrobial agent during root canal treatment.}, } @article {pmid32188097, year = {2020}, author = {Labena, A and Hegazy, MA and Sami, RM and Hozzein, WN}, title = {Multiple Applications of a Novel Cationic Gemini Surfactant: Anti-Microbial, Anti-Biofilm, Biocide, Salinity Corrosion Inhibitor, and Biofilm Dispersion (Part II).}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {6}, pages = {}, pmid = {32188097}, issn = {1420-3049}, support = {RSP-2019/53//King Saud University/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cations ; Corrosion ; Disinfectants/*pharmacology ; Microbial Sensitivity Tests ; *Salinity ; Surface-Active Agents/*pharmacology ; }, abstract = {The Egyptian petroleum industries are incurring severe problems with corrosion, particularly corrosion that is induced by sulfidogenic microbial activities in harsh salinity environments despite extensively using biocides and metal corrosion inhibitors. Therefore, in this study, a synthesized cationic gemini surfactant (SCGS) was tested as a broad-spectrum antimicrobial, anti-bacterial, anti-candida, anti-fungal, anti-biofilm (anti-adhesive), and bio-dispersion agent. The SCGS was evaluated as a biocide against environmental sulfidogenic-bacteria and as a corrosion inhibitor for a high salinity cultivated medium. The SCGS displayed wide spectrum antimicrobial activity with minimum bactericidal/fungicidal inhibitory concentrations. The SCGS demonstrated anti-bacterial, anti-biofilm, and bio-dispersion activity. The SCGS exhibited bactericidal activity against environmental sulfidogenic bacteria and the highest corrosion inhibition efficiency of 93.8% at 5 mM. Additionally, the SCGS demonstrated bio-dispersion activity against the environmental sulfidogenic bacteria at 5.49% salinity. In conclusion, this study provides a novel synthesized cationic surfactant with many applications in the oil and gas industry: as broad-spectrum antimicrobial and anti-biofilm agents, corrosion inhibition for high salinity, biocides for environmentally sulfidogenic bacteria, and as bio-dispersion agents.}, } @article {pmid32185542, year = {2020}, author = {Kerfahi, D and Harvey, BP and Agostini, S and Kon, K and Huang, R and Adams, JM and Hall-Spencer, JM}, title = {Responses of Intertidal Bacterial Biofilm Communities to Increasing pCO2.}, journal = {Marine biotechnology (New York, N.Y.)}, volume = {22}, number = {6}, pages = {727-738}, doi = {10.1007/s10126-020-09958-3}, pmid = {32185542}, issn = {1436-2236}, mesh = {Aquatic Organisms ; Bacteria/*classification/genetics ; Bacterial Physiological Phenomena ; *Biofilms ; Carbon Dioxide/*chemistry ; Ecosystem ; Japan ; RNA, Ribosomal, 16S/genetics ; Seawater/*chemistry ; }, abstract = {The effects of ocean acidification on ecosystems remain poorly understood, because it is difficult to simulate the effects of elevated CO2 on entire marine communities. Natural systems enriched in CO2 are being used to help understand the long-term effects of ocean acidification in situ. Here, we compared biofilm bacterial communities on intertidal cobbles/boulders and bedrock along a seawater CO2 gradient off Japan. Samples sequenced for 16S rRNA showed differences in bacterial communities with different pCO2 and between habitat types. In both habitats, bacterial diversity increased in the acidified conditions. Differences in pCO2 were associated with differences in the relative abundance of the dominant phyla. However, despite the differences in community composition, there was no indication that these changes would be significant for nutrient cycling and ecosystem function. As well as direct effects of seawater chemistry on the biofilm, increased microalgal growth and decreased grazing may contribute to the shift in bacterial composition at high CO2, as documented by other studies. Thus, the effects of changes in bacterial community composition due to globally increasing pCO2 levels require further investigation to assess the implications for marine ecosystem function. However, the apparent lack of functional shifts in biofilms along the pCO2 gradient is a reassuring indicator of stability of their ecosystem functions in shallow ocean margins.}, } @article {pmid32185467, year = {2020}, author = {Zhu, ML and Wang, YH and Dai, Y and Wu, XQ and Ye, JR}, title = {Effects of Different Culture Conditions on the Biofilm Formation of Bacillus pumilus HR10.}, journal = {Current microbiology}, volume = {77}, number = {8}, pages = {1405-1411}, pmid = {32185467}, issn = {1432-0991}, support = {2017YFD0600104//National Key Research and Development Program of China/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; }, mesh = {Bacillus pumilus/*physiology ; *Bacteriological Techniques ; Biofilms/*growth & development ; Hydrogen-Ion Concentration ; Plant Roots/*microbiology ; Rhizosphere ; Salinity ; Salt Tolerance ; Soil Microbiology ; Temperature ; }, abstract = {Many studies have focused on the significant role of biofilm formation by Bacillus in the biocontrol process. Bacillus pumilus HR10 is a plant growth-promoting rhizobacterium with multiple biocontrol functions, including promoting growth, controlling pathogens, and assisting in the formation of mycorrhizae. Currently, there is no relevant report on the biofilm formation of B. pumilus HR10 and its influencing factors. B. pumilus HR10 was found to easily form a stable biofilm structure on the surface of media, with awesome swarming ability. The optimum temperature for biofilm formation was 37 °C. B. pumilus HR10 formed most obviously at pH 7.0 and was not extremely sensitive to acidic or alkaline conditions. Most of the polysaccharide components of plant root exudates promoted the biofilm formation by B. pumilus HR10, with glucose having the greatest promoting effect. Low concentrations of Fe[2+], Mg[2+], Ca[2+], K[+], and Na[+] enhanced biofilm formation. In summary, biofilm formation can improve the tolerance of B. pumilus HR10 to salt and certain heavy metal ion stresses and contribute to its application in different plants and soils with high salinity or heavy metals in the field.}, } @article {pmid32184763, year = {2020}, author = {Alonso, VPP and Harada, AMM and Kabuki, DY}, title = {Competitive and/or Cooperative Interactions of Listeria monocytogenes With Bacillus cereus in Dual-Species Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {177}, pmid = {32184763}, issn = {1664-302X}, abstract = {Microorganisms in dairy industries can form monospecies, dual-species, or multispecies biofilms, showing cooperative or competitive behaviors, which might contribute to the reduction of efficiency of cleaning and sanitization processes and eventually turn into a potential source of contamination. This study proposes to evaluate the behavior of Listeria monocytogenes in monospecies biofilms, cocultured with Bacillus cereus. The isolates were of dairy origin, and the selection occurred after studies of competition among species. The biofilm formations on AISI 304 stainless steel at 25°C in a stationary culture were analyzed to observe the cooperative or competitive interactions among species, as well as the effect of pre-adhered cells. Biofilm formation assays were performed in four experiments: Experiment 1: in the presence of strains of antagonistic substance producer B. cereus (+); Experiment 2: extract of the antagonistic substance of B. cereus; Experiment 3: pre-adhered cells of B. cereus; and Experiment 4: pre-adhered cells of L. monocytogenes. Subsequently, cooperative behavior was observed by scanning electron microscopy. The L. monocytogenes monospecies biofilm counts of greater than 5 log colony-forming units (CFU)/cm[2] were also observed in dual-species biofilms in the presence of B. cereus (non-producers of antagonist substance), showing cooperative behavior between species. However, in the presence of antagonistic substance produced by B. cereus, the counts were lower, 1.39 and 1.70 log CFU/cm[2] (p > 0.05), indicating that the antagonistic substance contributes to competitive interactions. These data are relevant for the development of new studies to control L. monocytogenes in the dairy industry.}, } @article {pmid32183203, year = {2020}, author = {Kabir, MN and Aras, S and Wadood, S and Chowdhury, S and Fouladkhah, AC}, title = {Fate and Biofilm Formation of Wild-Type and Pressure-Stressed Pathogens of Public Health Concern in Surface Water and on Abiotic Surfaces.}, journal = {Microorganisms}, volume = {8}, number = {3}, pages = {}, pmid = {32183203}, issn = {2076-2607}, abstract = {Since the historic outbreak near Broad Street in London, which serves as cornerstone of modern epidemiology, infectious diseases spread in surface and sub-surface water has been a persisting public health challenge. The current study investigated persistence of wild-type and pressure-stressed Listeria monocytogenes, Escherichia coli O157:H7, and non-typhoidal Salmonella enterica serovars in surface water stored aerobically for up to 28 days at 5, 25, and 37 °C. Additionally, biofilm formation of wild-type and pressure-stressed non-typhoidal Salmonella serovars were monitored on surface of stainless steel and rubber coupons for 28 days at 25 and 37 °C. While L. monocytogenes exhibited a lower (p < 0.05) survival rate at 5 °C, relative to the two Gram-negative pathogens, at higher temperatures of 25 and 37 °C, all three pathogens exhibited similar (p ≥ 0.05) trends for survival in surface water. Both wild-type and pressure-stressed Salmonella serovars in the vast majority of tested times, temperatures, and surfaces exhibited comparable (p ≥ 0.05) persistence and biofilm formation capability. Our study thus indicates the occurrence of contamination could lead to prolonged survival of these microorganisms in low-nutrient environments and highlights the need for preventive measures such as those articulated under Produce Safety Rule of the U.S. Food Safety Modernization Act.}, } @article {pmid32182913, year = {2020}, author = {Xie, F and Zan, Y and Zhang, X and Zhang, H and Jin, M and Zhang, W and Zhang, Y and Liu, S}, title = {Differential Abilities of Mammalian Cathelicidins to Inhibit Bacterial Biofilm Formation and Promote Multifaceted Immune Functions of Neutrophils.}, journal = {International journal of molecular sciences}, volume = {21}, number = {5}, pages = {}, pmid = {32182913}, issn = {1422-0067}, support = {31873016//National Natural Science Foundation of China/ ; 31772757//National Natural Science Foundation of China/ ; 2017YFD0500102//National Key Research and Development Program of China/ ; QC2016044//Natural Science Foundation of Heilongjiang Province/ ; YQ2019C031//Natural Science Foundation of Heilongjiang Province/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Cathelicidins/*pharmacology ; Female ; Humans ; Immunologic Factors/*pharmacology ; Lung/drug effects ; Mammals/*metabolism ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests/methods ; Neutrophils/*drug effects ; }, abstract = {Mammalian cathelicidins act as the potent microbicidal molecules for controlling bacterial infection, and are considered promising alternatives to traditional antibiotics. Their ability to modulate host immune responses, as well as their bactericidal activities, is essential for therapeutic interventions. In this study, we compared the bactericidal activities, antibiofilm activities and immune-modulatory properties of cathelicidins BMAP-27, BMAP-34, mCRAMP, and LL-37, and evaluated the therapeutic efficacy of the combination of BMAP-27 and LL-37 using a mouse pulmonary infection model. Our results showed that all of the four cathelicidins effectively killed bacteria via rapid induction of membrane permeabilization, and BMAP-27 exhibited the most excellent bactericidal activity against diverse bacterial pathogens. BMAP-27, mCRAMP, and LL-37 effectively inhibited biofilm formation, while BMAP-34, mCRAMP and LL-37 exerted immunomodulatory functions with varying degrees of efficacy by stimulating the chemotaxis of neutrophils, inducing the production of reactive oxygen species, and facilitating the formation of neutrophil extracellular traps. Of note, the combination of BMAP-27 and LL-37 effectively enhanced the clearance of Pseudomonas aeruginosa and reduced the organ injury in vivo. Together, these findings highlight that identifying the appropriate synergistic combination of mammalian cathelicidins with different beneficial properties may be an effective strategy against bacterial infection.}, } @article {pmid32182506, year = {2020}, author = {Tsitouras, A and Basu, O and Al-Ghussain, N and Delatolla, R}, title = {Kinetic effects of anaerobic staging and aeration rates on sequencing batch moving bed biofilm reactors: Carbon, nitrogen, and phosphorus treatment of cheese production wastewater.}, journal = {Chemosphere}, volume = {252}, number = {}, pages = {126407}, doi = {10.1016/j.chemosphere.2020.126407}, pmid = {32182506}, issn = {1879-1298}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Carbon/analysis/metabolism ; *Cheese ; Eutrophication ; Food Handling ; Kinetics ; Nitrogen/analysis/metabolism ; Phosphorus/analysis/metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/microbiology ; }, abstract = {The food and beverage industry produces wastewaters containing high concentrations of organic carbon and nutrients, which when discharged leads to eutrophication and algal blooms. Given recent stringencies in effluent regulations, industries are required to treat their wastewater on-site. There is a critical need for compact, high-rate, cost-effective wastewater technologies to treat industrial wastewaters, such as the sequencing batch moving bed biofilm reactor. The aim of this study is to investigate the potential and evaluate the performance of the sequencing batch moving bed biofilm reactor cycling between anaerobic and aerobic stages to treat high-strength food and beverage wastewaters. Specifically, this study focuses on the effects of anaerobic staging times and enhanced aeration on the removal of carbon, nitrogen, and phosphorous from cheese production wastewaters. Increasing anaerobic staging times was found to improve the removal rates of carbon beyond previously reported moving bed biofilm reactor results. Increasing the anaerobic stage however decreased the total nitrogen removal, with organic nitrogen undergoing ammonification during the anaerobic stage. This study demonstrates an optimum anaerobic staging time of 138 min; with a carbon removal rate of 31.1 g-sCOD·m[-2]d[-1] and a nitrogen removal rate of 1.3 g-N·m[-2]d[-1]. Enhanced aeration was found to be detrimental to phosphorous removal, where a moderate aeration rate demonstrated a net total phosphorous removal of approximately 22 mg-P·l[-1] with the phosphorous-content of the suspended solids being approximately 4%. Finally, the sequencing batch moving bed biofilm reactor shows potential for on-site treatment of carbon, nitrogen, and phosphorous from cheese production wastewater.}, } @article {pmid32182142, year = {2020}, author = {Qiu, Y and Wu, Y and Lu, B and Zhu, G and Gong, T and Wang, R and Peng, Q and Li, Y}, title = {Inhibition of methicillin-resistant Staphylococcus aureus (MRSA) biofilm by cationic poly (D, L-lactide-co-glycolide) nanoparticles.}, journal = {Biofouling}, volume = {36}, number = {2}, pages = {159-168}, doi = {10.1080/08927014.2020.1740687}, pmid = {32182142}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cations ; Dose-Response Relationship, Drug ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Plankton/drug effects/microbiology ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry/*pharmacology ; Time Factors ; Vancomycin/pharmacology ; }, abstract = {The emergent need for new treatment methods for multi-drug resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) has focused attention on novel potential tools like nanoparticles (NPs). In the present study, a drug-free cationic nanoparticles (CNPs) system was developed and its anti-MRSA effects were firstly investigated. The results showed that CNPs (261.7 nm, 26.1 mv) showed time- and concentration-dependent activity against MRSA growth, killing ∼ 90% of planktonic bacterial cells in 3 h at 400 μg ml[-1], and completely inhibiting biofilm formation at 1000 μg ml[-1]. Moreover, CNPs at 400 μg ml[-1] reduced the minimum inhibitory concentration (MIC) of vancomycin on inhibition of planktonic MRSA growth (∼ 25%) and biofilm formation (∼ 50%). The CNPs-bacteria interaction force was up to 22 nN. Overall, these data suggest that CNPs have a good potential in clinical applications for the prevention and treatment of MRSA infection.}, } @article {pmid32180020, year = {2020}, author = {Mishra, S and Yang, X and Ray, S and Fraceto, LF and Singh, HB}, title = {Antibacterial and biofilm inhibition activity of biofabricated silver nanoparticles against Xanthomonas oryzae pv. oryzae causing blight disease of rice instigates disease suppression.}, journal = {World journal of microbiology & biotechnology}, volume = {36}, number = {4}, pages = {55}, pmid = {32180020}, issn = {1573-0972}, support = {31700457//National Natural Science Foundation of China/ ; 2019PC0095//CAS President's International Fellowship Initiative (PIFI)/ ; 2018M631112//China Postdoctoral Science Foundation/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Metal Nanoparticles ; Microbial Sensitivity Tests ; Oryza/*growth & development/microbiology ; Particle Size ; Plant Diseases/microbiology/prevention & control ; Silver/chemistry/*pharmacology ; Xanthomonas/*drug effects/physiology ; }, abstract = {Antimicrobial activity of silver nanoparticles (AgNPs) has been well documented in earlier studies. As their efficient role in combating phytopathogens has begun recently, there is a huge scope to explore their effectiveness in agriculture. Considering the strong antifungal activity of biosynthesized AgNPs (as reported in our previous study), our main aim is to elucidate their antibacterial activity against bacterial plant pathogens to authenticate their wide range of agricultural applications. The present manuscript highlights the potential role of biosynthesized AgNPs against Xanthomonas oryzae pv. oryzae (Xoo) causing disastrous sheath blight disease of rice worldwide. We observed strong antibacterial activity of biosynthesized AgNPs (size ~ 12 nm) against Xoo at 20, 30 and 50 µg/mL concentrations. The significant inhibitory impact of AgNPs on biofilm formation by Xoo was noted even at the lower dose of 5 µg/mL (p = 0.001). Maximum biofilm inhibition (p = 0.000) was caused at 50 µg/mL concentration of AgNPs in comparison to control. Furthermore, disease suppression by biosynthesized AgNPs was authenticated under greenhouse conditions. Foliar spray of AgNPs significantly reduced the blight symptoms in rice sheaths as shown by 9.25% DLA (% Diseased leaf area) as compared to 33.91% DLA in Xoo inoculated rice plants. Altogether, our data suggest that biosynthesized AgNPs based nanoformulation can be applied for successful management of blight disease of rice. In addition, the antibiofilm strategies instigated by AgNPs can be exploited against a wide range of bacterial phytopathogens. In light of rapidly emerging antibiotic-resistant microbial strains, the current work provides an alternate effective platform for the application of nanoformulation for augmenting sustainability in the agriculture.}, } @article {pmid32179838, year = {2020}, author = {Besser, M and Dietrich, M and Weber, L and Rembe, JD and Stuermer, EK}, title = {Efficacy of antiseptics in a novel 3-dimensional human plasma biofilm model (hpBIOM).}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {4792}, pmid = {32179838}, issn = {2045-2322}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biguanides/*pharmacology ; *Biofilms ; Drug Resistance, Bacterial ; Glycocalyx ; Humans ; Imines ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests/*methods ; Plasma/*microbiology ; Pseudomonas aeruginosa/*drug effects ; Pyridines/*pharmacology ; Time Factors ; Translational Research, Biomedical ; }, abstract = {The increasing incidence of non-healing wounds constitutes a pivotal socio-economic burden. 60-80% of chronic wounds are colonized by pathogenic microorganisms within a protective extracellular polymeric substance, bearing a great challenge in wound management. Human plasma was used to prepare the biofilm model (hpBIOM), adding pathogens to the plasma and forming Coagula-like discs with integrated pathogens were produced. The antiseptics Octenisept and Lavasorb were tested regarding their antibacterial properties on clinically relevant biofilm-growing bacteria (MRSA, P. aeruginosa) in the hpBIOM. Biofilm-typical glycocalyx-formation was confirmed using immunohistochemical staining. Treatment of a 12 h-maturated biofilm with Octenisept resulted in complete eradication of P. aeruginosa and MRSA after 48 h. Lavasorb proved less effective than Octenisept in this setting. In more mature biofilms (24 h), both antiseptics showed a delayed, partially decreased efficacy. Summarized, the hpBIOM provides essential factors for a translational research approach to be used for detailed human biofilm analyses and evaluation of antimicrobial/-biofilm properties of established and novel therapeutic strategies and products. Octenisept and Lavasorb showed an attenuated efficacy in the hpBIOM compared to planktonic conditions and previously published biofilm-studies, prompting the question for the necessity of introducing new international standards and pre-admission requirements on a translational base.}, } @article {pmid32179736, year = {2019}, author = {El-Awady, A and de Sousa Rabelo, M and Meghil, MM and Rajendran, M and Elashiry, M and Stadler, AF and Foz, AM and Susin, C and Romito, GA and Arce, RM and Cutler, CW}, title = {Polymicrobial synergy within oral biofilm promotes invasion of dendritic cells and survival of consortia members.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {11}, pmid = {32179736}, issn = {2055-5008}, support = {R01 DE014328/DE/NIDCR NIH HHS/United States ; R01 DE029468/DE/NIDCR NIH HHS/United States ; R21 DE020916/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Coinfection/*microbiology ; Dendritic Cells/*microbiology ; Fimbriae, Bacterial/genetics ; Fusobacterium nucleatum/genetics/physiology ; Gingiva/*microbiology ; Humans ; Inflammation ; *Microbial Consortia ; Microbiota ; Periodontitis/*microbiology ; Porphyromonas gingivalis/genetics/physiology ; RNA, Ribosomal, 16S/genetics ; Streptococcus gordonii/genetics/physiology ; }, abstract = {Years of human microbiome research have confirmed that microbes rarely live or function alone, favoring diverse communities. Yet most experimental host-pathogen studies employ single species models of infection. Here, the influence of three-species oral microbial consortium on growth, virulence, invasion and persistence in dendritic cells (DCs) was examined experimentally in human monocyte-derived dendritic cells (DCs) and in patients with periodontitis (PD). Cooperative biofilm formation by Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis was documented in vitro using growth models and scanning electron microscopy. Analysis of growth rates by species-specific 16s rRNA probes revealed distinct, early advantages to consortium growth for S. gordonii and F. nucleatum with P. gingivalis, while P. gingivalis upregulated its short mfa1 fimbriae, leading to increased invasion of DCs. F. nucleatum was only taken up by DCs when in consortium with P. gingivalis. Mature consortium regressed DC maturation upon uptake, as determined by flow cytometry. Analysis of dental plaques of PD and healthy subjects by 16s rRNA confirmed oral colonization with consortium members, but DC hematogenous spread was limited to P. gingivalis and F. nucleatum. Expression of P. gingivalis mfa1 fimbriae was increased in dental plaques and hematogenous DCs of PD patients. P. gingivalis in the consortium correlated with an adverse clinical response in the gingiva of PD subjects. In conclusion, we have identified polymicrobial synergy in a three-species oral consortium that may have negative consequences for the host, including microbial dissemination and adverse peripheral inflammatory responses.}, } @article {pmid32178462, year = {2020}, author = {Gkotsis, P and Zouboulis, A and Mitrakas, M}, title = {Using Additives for Fouling Control in a Lab-Scale MBR; Comparing the Anti-Fouling Potential of Coagulants, PAC and Bio-Film Carriers.}, journal = {Membranes}, volume = {10}, number = {3}, pages = {}, pmid = {32178462}, issn = {2077-0375}, abstract = {This study investigates the effect of different additives, such as coagulants/flocculants, adsorption agents (powdered activated carbon, PAC), and bio-film carriers, on the fouling propensity of a lab-scale membrane bio-reactor (MBR) treating synthetic municipal wastewater. The coagulation agents FO 4350 SSH, Adifloc KD 451, and PAC1 A9-M at concentrations of 10 mg/L, 10 mg/L, and 100 mg Al/L, respectively, and PAC at a concentration of 3.6 ± 0.1 g/L, exhibited the best results during their batch-mode addition to biomass samples. The optimal additives FO 4350 SSH and Adifloc KD 451 were continuously added to the bioreactor at continuous-flow addition experiments and resulted in increased membrane lifetime by 16% and 13%, respectively, suggesting that the decrease of SMPc concentration and the increase of sludge filterability is the dominant fouling reduction mechanism. On the contrary, fouling reduction was low when PAC1 A9-M and PAC were continuously added, as the membrane lifetime was increased by approximately 6%. Interestingly, the addition of bio-film carriers (at filling ratios of 40%, 50%, and 60%) did not affect SMPc concentration, sludge filterability, and trans-membrane pressure (TMP). Finally, the effluent quality was satisfactory in terms of organics and ammonia removal, as chemical oxygen demand (COD), biochemical oxygen demand (BOD)5, and ΝΗ-N concentrations were consistently below the permissible discharge limits and rarely exceeded 30, 15, and 0.9 mg/L, respectively.}, } @article {pmid32178447, year = {2020}, author = {Faria, SI and Teixeira-Santos, R and Romeu, MJ and Morais, J and Vasconcelos, V and Mergulhão, FJ}, title = {The Relative Importance of Shear Forces and Surface Hydrophobicity on Biofilm Formation by Coccoid Cyanobacteria.}, journal = {Polymers}, volume = {12}, number = {3}, pages = {}, pmid = {32178447}, issn = {2073-4360}, support = {UIDB/00511/2020//Fundação para a Ciência e a Tecnologia/ ; 0302_CVMAR_I_1_P//Interreg/ ; UIDB/04423/2020//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {Understanding the conditions affecting cyanobacterial biofilm development is crucial to develop new antibiofouling strategies and decrease the economic and environmental impact of biofilms in marine settings. In this study, we investigated the relative importance of shear forces and surface hydrophobicity on biofilm development by two coccoid cyanobacteria with different biofilm formation capacities. The strong biofilm-forming Synechocystis salina was used along with the weaker biofilm-forming Cyanobium sp. Biofilms were developed in defined hydrodynamic conditions using glass (a model hydrophilic surface) and a polymeric epoxy coating (a hydrophobic surface) as substrates. Biofilms developed in both surfaces at lower shear conditions contained a higher number of cells and presented higher values for wet weight, thickness, and chlorophyll a content. The impact of hydrodynamics on biofilm development was generally stronger than the impact of surface hydrophobicity, but a combined effect of these two parameters strongly affected biofilm formation for the weaker biofilm-producing organism. The antibiofilm performance of the polymeric coating was confirmed at the hydrodynamic conditions prevailing in ports. Shear forces were shown to have a profound impact on biofilm development in marine settings regardless of the fouling capacity of the existing flora and the hydrophobicity of the surface.}, } @article {pmid32178243, year = {2020}, author = {Zeng, B and Wang, C and Zhang, P and Guo, Z and Chen, L and Duan, K}, title = {Heat Shock Protein DnaJ in Pseudomonas aeruginosa Affects Biofilm Formation via Pyocyanin Production.}, journal = {Microorganisms}, volume = {8}, number = {3}, pages = {}, pmid = {32178243}, issn = {2076-2607}, support = {IRT-15R55//IRT/ ; RGPIN-05864-2019//Natural Sciences and Engineering Research Council of Canada/ ; 2018JM3013//Provincial Natural Science Foundation of Shaanxi Province/ ; }, abstract = {Heat shock proteins (HSPs) play important biological roles, and they are implicated in bacterial response to environmental stresses and in pathogenesis of infection. The role of HSPs in P. aeruginosa, however, remains to be fully elucidated. Here, we report the unique role of HSP DnaJ in biofilm formation and pathogenicity in P. aeruginosa. A dnaJ mutant produced hardly any pyocyanin and formed significantly less biofilms, which contributed to decreased pathogenicity as demonstrated by reduced mortality rate in a Drosophila melanogaster infection model. The reduced pyocyanin production in the dnaJ mutant was a result of the decreased transcription of phenazine synthesis operons including phzA1, phzA2, phzS, and phzM. The reduction of biofilm formation and initial adhesion in the dnaJ mutant could be reversed by exogenously added pyocyanin or extracellular DNA (eDNA). Consistent with such observations, absence of dnaJ significantly reduced the release of eDNA in P. aeruginosa and addition of exogenous pyocyanin could restore eDNA release. These results indicate dnaJ mutation caused reduced pyocyanin production, which in turn caused the decreased eDNA, resulting in decreased biofilm formation. DnaJ is required for pyocyanin production and full virulence in P. aeruginosa; it affects biofilm formation and initial adhesion via pyocyanin, inducing eDNA release.}, } @article {pmid32176702, year = {2020}, author = {Wu, DC and Zamorano-Sánchez, D and Pagliai, FA and Park, JH and Floyd, KA and Lee, CK and Kitts, G and Rose, CB and Bilotta, EM and Wong, GCL and Yildiz, FH}, title = {Reciprocal c-di-GMP signaling: Incomplete flagellum biogenesis triggers c-di-GMP signaling pathways that promote biofilm formation.}, journal = {PLoS genetics}, volume = {16}, number = {3}, pages = {e1008703}, pmid = {32176702}, issn = {1553-7404}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; S10 OD023528/OD/NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/genetics/metabolism ; Fimbriae, Bacterial/metabolism ; Flagella/*metabolism/physiology ; Gene Expression Regulation, Bacterial/genetics ; Phosphorus-Oxygen Lyases/genetics/metabolism ; Second Messenger Systems/physiology ; Signal Transduction/physiology ; Vibrio cholerae/genetics/metabolism ; }, abstract = {The assembly status of the V. cholerae flagellum regulates biofilm formation, suggesting that the bacterium senses a lack of movement to commit to a sessile lifestyle. Motility and biofilm formation are inversely regulated by the second messenger molecule cyclic dimeric guanosine monophosphate (c-di-GMP). Therefore, we sought to define the flagellum-associated c-di-GMP-mediated signaling pathways that regulate the transition from a motile to a sessile state. Here we report that elimination of the flagellum, via loss of the FlaA flagellin, results in a flagellum-dependent biofilm regulatory (FDBR) response, which elevates cellular c-di-GMP levels, increases biofilm gene expression, and enhances biofilm formation. The strength of the FDBR response is linked with status of the flagellar stator: it can be reversed by deletion of the T ring component MotX, and reduced by mutations altering either the Na+ binding ability of the stator or the Na+ motive force. Absence of the stator also results in reduction of mannose-sensitive hemagglutinin (MSHA) pilus levels on the cell surface, suggesting interconnectivity of signal transduction pathways involved in biofilm formation. Strains lacking flagellar rotor components similarly launched an FDBR response, however this was independent of the status of assembly of the flagellar stator. We found that the FDBR response requires at least three specific diguanylate cyclases that contribute to increased c-di-GMP levels, and propose that activation of biofilm formation during this response relies on c-di-GMP-dependent activation of positive regulators of biofilm production. Together our results dissect how flagellum assembly activates c-di-GMP signaling circuits, and how V. cholerae utilizes these signals to transition from a motile to a sessile state.}, } @article {pmid32176238, year = {2019}, author = {Gliosca, LA and D Eramo, LR and Bozza, FL and Soken, L and Abusamra, L and Salgado, PA and Squassi, AF and Molgatini, SL}, title = {Microbiological study of the subgingival biofilm in HIV+/HAART patients at a specialized dental service.}, journal = {Acta odontologica latinoamericana : AOL}, volume = {32}, number = {3}, pages = {147-155}, pmid = {32176238}, issn = {1852-4834}, support = {UBACyT 20720120100008BA//Research Support Programme for Universidad de Buenos Aires/Argentina ; UBACyT 20020120100324BA//Research Support Programme for Universidad de Buenos Aires/Argentina ; }, mesh = {Adult ; Aged ; Aggregatibacter actinomycetemcomitans/isolation & purification ; Anti-HIV Agents/pharmacology ; *Antiretroviral Therapy, Highly Active ; Argentina ; Biofilms ; Dental Health Services ; Dental Plaque/microbiology ; Female ; Gingiva/*microbiology ; HIV Infections/complications/*drug therapy/*microbiology ; Humans ; Male ; Middle Aged ; Periodontal Diseases ; Periodontal Pocket/*microbiology ; Periodontitis/complications/*microbiology ; Porphyromonas gingivalis/isolation & purification ; Tannerella forsythia ; Treponema denticola ; }, abstract = {The aim of this study was to describe the microbiological profile of HIV patients under highly active antiretroviral treatment (HAART). This crosssectional study comprised 32 HIV patients with periodontal disease (PD) who had been under HAART for more than 6 months. Information about the patients' medical history was obtained from clinical records. Clinical dental examination was performed by a calibrated researcher using standard dental instruments to determine probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). A total 4,765 periodontal sites were evaluated, 125 of which were also studied microbiologically. Subgingival biofilm samples were obtained using sterile paper points; one set was used for microbiological culture studies and the other for endpoint PCR. Statistical analysis was performed using KruskalWallis and posthoc DunnBonferroni contrast tests. All participants were on HAART at the time of the study, and 90.6% had a viral load below 50 copies / mm3. Prevalence of periodontally active sites was low in the study population. Microbiological studies: Black pigmented anaerobic bacteria and fusiform CFU counts were significantly higher in samples from sites with BOP and PD ≥4mm (p 0.020 and p 0.005, respectively). Molecular Assays: Detection of Porphyromonas gingivalis (p 0.002), Tannerella forsythia (p 0.023) and Treponema denticola (p 0.015) was significantly more frequent at sites with BOP and PD ≥4mm. Conclusions: The patients living with HIV/AIDS under HAART studied here had low prevalence of clinical periodontal disease signs. However, significant detection of P. gingivalis, T. denticola, and T. forsythia in periodontal active sites, and the involvement of these microorganisms as potential HIV reactivators, show the importance of creating awareness among dental health professionals of the need for close dental and periodontal monitoring in HIV patients.}, } @article {pmid32174897, year = {2020}, author = {Bergsveinson, J and Roy, J and Maynard, C and Sanschagrin, S and Freeman, CN and Swerhone, GDW and Dynes, JJ and Tremblay, J and Greer, CW and Korber, DR and Lawrence, JR}, title = {Metatranscriptomic Insights Into the Response of River Biofilm Communities to Ionic and Nano-Zinc Oxide Exposures.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {267}, pmid = {32174897}, issn = {1664-302X}, abstract = {Manufactured Zn oxide nanoparticle (ZnO-NP) are extensively used world-wide in personal care and industrial products and are important contaminants of aquatic environments. To understand the overall impact of ZnO-NP contamination on aquatic ecosystems, investigation of their toxicity on aquatic biofilms is of particular consequence, given biofilms are known sinks for NP contaminants. In order to assess alterations in the functional activity of river microbial biofilm communities as a result of environmentally-relevant ZnO-NP exposure, biofilms were exposed to ionic zinc salt or ZnOPs that were uncoated (hydrophilic), coated with silane (hydrophobic) or stearic acid (lipophilic), at a total concentration of 188 μg l[-1] Zn. ICP-MS analyses of biofilms indicated ZnO-NP concentrated in the biofilms, with hydrophilic, hydrophobic, and lipophilic treatments reaching 0.310, 0.250, and 0.220 μg Zn cm[-2] of biofilm, respectively, while scanning transmission X-ray microspectroscopy (STXM) analyses of biofilms confirmed that Zn was extensively- and differentially-sorbed to biofilm material. Microbial community composition, based on taxonomic affiliation of mRNA sequences and enumeration of protozoa and micrometazoa, was not affected by these treatments, and the total transcriptional response of biofilms to all experimental exposures was not indicative of a global toxic-response, as cellular processes involved in general cell maintenance and housekeeping were abundantly transcribed. Transcripts related to major biological processes, including photosynthesis, energy metabolism, nitrogen metabolism, lipid metabolism, membrane transport, antibiotic resistance and xenobiotic degradation, were differentially expressed in Zn-exposures relative to controls. Notably, transcripts involved in nitrogen fixation and photosynthesis were decreased in abundance in response to Zn-exposure, while transcripts related to lipid degradation and motility-chemotaxis were increased, suggesting a potential role of Zn in biofilm dissolution. ZnO-NP and ionic Zn exposures elicited generally overlapping transcriptional responses, however hydrophilic and hydrophobic ZnO-NPs induced a more distinct effect than that of lipophilic ZnO-NPs, which had an effect similar to that of low ionic Zn exposure. While the physical coating of ZnO-NP may not induce specific toxicity observable at a community level, alteration of ecologically important processes of photosynthesis and nitrogen cycling are an important potential consequence of exposure to ionic Zn and Zn oxides.}, } @article {pmid32174561, year = {2020}, author = {Cheng, L and Min, D and Liu, DF and Zhu, TT and Wang, KL and Yu, HQ}, title = {Deteriorated biofilm-forming capacity and electroactivity of Shewanella oneidnsis MR-1 induced by insertion sequence (IS) elements.}, journal = {Biosensors & bioelectronics}, volume = {156}, number = {}, pages = {112136}, doi = {10.1016/j.bios.2020.112136}, pmid = {32174561}, issn = {1873-4235}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; DNA Transposable Elements ; Electricity ; Shewanella/genetics/growth & development/*physiology ; }, abstract = {Shewanella oneidensis MR-1, a model species of exoelectrogenic bacteria (EEB), has been widely applied in bioelectrochemical systems. Biofilms of EEB grown on electrodes are essential in governing the current output and power density of bioelectrochemical systems. The MR-1 genome is exceptionally dynamic due to the existence of a large number of insertion sequence (IS) elements. However, to date, the impacts of IS elements on the biofilm-forming capacity of EEB and performance of bioelectrochemical systems remain unrevealed. Herein, we isolated a non-motile mutant (NMM) with biofilm-deficient phenotype from MR-1. We found that the insertion of an ISSod2 element into the flrA (encoding the master regulator for flagella synthesis and assembly) of MR-1 resulted in the non-motile and biofilm-deficient phenotypes in NMM cells. Notably, such a variant was readily confused with the wild-type strain because there were no obvious differences in growth rates and colonial morphologies between the two strains. However, the reduced biofilm formation on the electrodes and the deteriorated performances of bioelectrochemical systems and Cr(VI) immobilization for the strain NMM were observed. Given the wide distribution of IS elements in EEB, appropriate cultivation and preservation conditions should be adopted to reduce the likelihood that IS elements-mediated mutation occurs in EEB. These findings reveal the negative impacts of IS elements on the biofilm-forming capacity of EEB and performance of bioelectrochemical systems and suggest that great attention should be given to the actual physiological states of EEB before their applications.}, } @article {pmid32173268, year = {2020}, author = {Gonçalves, B and Bernardo, R and Wang, C and Schröder, MS and Pedro, NA and Butler, G and Azeredo, J and Henriques, M and Pereira Mira, N and Silva, S}, title = {Effect of progesterone on Candida albicans biofilm formation under acidic conditions: A transcriptomic analysis.}, journal = {International journal of medical microbiology : IJMM}, volume = {310}, number = {3}, pages = {151414}, doi = {10.1016/j.ijmm.2020.151414}, pmid = {32173268}, issn = {1618-0607}, mesh = {Acids/*pharmacology ; Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/*genetics ; Candidiasis, Vulvovaginal/microbiology ; Female ; Fluconazole/pharmacology ; Fungal Proteins/genetics ; *Gene Expression Profiling ; Humans ; Hydrogen-Ion Concentration ; Progesterone/*pharmacology ; Transcriptome ; Virulence/drug effects ; }, abstract = {Vulvovaginal candidiasis (VVC) caused by Candida albicans is a common disease worldwide. A very important C. albicans virulence factor is its ability to form biofilms on epithelium and/or on intrauterine devices promoting VVC. It has been shown that VVC has a hormonal dependency and that progesterone affects virulence traits of C. albicans cells. To understand how the acidic environment (pH 4) and progesterone (either alone and in combination) modulate C. albicans response during formation of biofilm, a transcriptomic analysis was performed together with characterization of the biofilm properties. Compared to planktonic cells, acidic biofilm-cells exhibited major changes in their transcriptome, including modifications in the expression of 286 genes that were not previously associated with biofilm formation in C. albicans. The vast majority of the genes up-regulated in the acidic biofilm cells (including those uniquely identified in our study) are known targets of Sfl1, and consistently, Sfl1 deletion is herein shown to impair the formation of acidic biofilms (pH 4). Under the acidic conditions used, the presence of progesterone reduced C. albicans biofilm biomass and structural cohesion. Transcriptomic analysis of biofilms developed in the presence of progesterone led to the identification of 65 down-regulated genes including, among others, the regulator Tec1 and several of its target genes, suggesting that the function of this transcription factor is inhibited by the presence of the hormone. Additionally, progesterone reduced the susceptibility of biofilm cells to fluconazole, consistent with an up-regulation of efflux pumps. Overall, the results of this study show that progesterone modulates C. albicans biofilm formation and genomic expression under acidic conditions, which may have implications for C. albicans pathogenicity in the vaginal environment.}, } @article {pmid32172878, year = {2020}, author = {Affes, S and Maalej, H and Aranaz, I and Kchaou, H and Acosta, N and Heras, Á and Nasri, M}, title = {Controlled size green synthesis of bioactive silver nanoparticles assisted by chitosan and its derivatives and their application in biofilm preparation.}, journal = {Carbohydrate polymers}, volume = {236}, number = {}, pages = {116063}, doi = {10.1016/j.carbpol.2020.116063}, pmid = {32172878}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/drug effects ; Chitosan/*analogs & derivatives ; Food Packaging ; Free Radical Scavengers/chemistry/*pharmacology ; Green Chemistry Technology ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Silver/chemistry/*pharmacology ; }, abstract = {The aim of this work was to explore the effect of various molecular weight (Mw) chitosan depolymerization products (CDP) on the silver nanoparticles (AgNPs) and chitosan/AgNPs blend films production. Produced AgNPs, stable during 30 days in a colloïdal form, were characterized in terms of UV-vis, transmission electron microscopy (TEM), dynamic light scattering (DLS) and fourier transform infrared spectroscopy (FTIR) analyses. AgNPs displayed interesting antibacterial and antioxidant properties that were affected by the physicochemical properties of used chitosans. Interestingly, CDP may be used for the preparation of bioactive and stable AgNPs. Additionally, chitosan/AgNPs blend films were prepared and characterized in terms of physiochemical and biological properties. As compared to the chitosan film, various properties were enhanced in the chitosan/AgNPs blend films, including light barrier, opacity, elongation at break, as well as bioactivities, thus suggesting that films could be used as novel alternative food packaging applications.}, } @article {pmid32172260, year = {2020}, author = {Hadadi-Fishani, M and Khaledi, A and Fatemi-Nasab, ZS}, title = {Correlation between biofilm formation and antibiotic resistance in Pseudomonas aeruginosa: a meta-analysis.}, journal = {Le infezioni in medicina}, volume = {28}, number = {1}, pages = {47-54}, pmid = {32172260}, issn = {2532-8689}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Ceftriaxone/pharmacology ; Colistin/pharmacology ; *Drug Resistance, Bacterial ; Humans ; Iran ; Polymyxin B/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Tobramycin/pharmacology ; }, abstract = {Biofilm formation is one of the important resistance mechanisms in Pseudomonas aeruginosa. This study aimed to consider the correlation between biofilm formation and antibiotic resistance in Pseudomonas aeruginosa through a systematic review and meta-analysis. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) strategies. Scientific databases were searched by MeSH terms and keywords such as "Pseudomonas aeruginosa", "biofilm formation", "antibiotic resistance", "prevalence" AND "Iran", to obtain articles published from 1st January 2016 to 30th November 2019. Studies recording biofilm formation and antibiotic resistance in P. aeruginosa recovered from clinical samples of Iranian patients were included. Data analysis was performed using CMA software. The combined biofilm formation rate was reported as 87.6 % (95% CI: 80-92.5). The heterogeneity index among the selected articles was Q2=96.5, I2=85.5, and t=0.26 (p=0.16). The pooled occurrences of strong, moderate and weak biofilms were 47.7% (95% CI: 28.7-67.3), 30.2% (95% CI: 19.4-43.8), and 27.4% (95% CI: 8.8-59.8), respectively. The pooled prevalence of MDR P. aeruginosa strains was as follows: 62.5% (95% CI: 40-77.2). The highest combined rates of antibiotic resistance were against ceftriaxone and tobramycin with the rates of 79.2.9% (95% CI: 54.2-96.2) and 64.4% (95% CI: 36.3-92), respectively. Also, the lowermost antibiotic resistance rates were against colistin and polymyxin B, with the prevalence of 2.1% (95% CI: 0.2-18.1), and 3% (95% CI: 0.5-17.3), respectively. More than half of the studies included in the present review showed a significant correlation between biofilm formation and antibiotic resistance pattern.}, } @article {pmid32172163, year = {2020}, author = {Banerjee, S and Vishakha, K and Das, S and Dutta, M and Mukherjee, D and Mondal, J and Mondal, S and Ganguli, A}, title = {Antibacterial, anti-biofilm activity and mechanism of action of pancreatin doped zinc oxide nanoparticles against methicillin resistant Staphylococcus aureus.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {190}, number = {}, pages = {110921}, doi = {10.1016/j.colsurfb.2020.110921}, pmid = {32172163}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Pancreatin/chemistry/*pharmacology ; Particle Size ; Surface Properties ; Zinc Oxide/chemistry/*pharmacology ; }, abstract = {Staphylococcus aureus are known to cause diseases from normal skin wound to life intimidating infections. Among the drug resistant strain, management of methicillin resistant Staphylococcus aureus (MRSA) is very difficult by using conventional antibiotic treatment. Both Zinc oxide nanoparticles (ZnONPs) and pancreatin (PK) are known to have antibacterial activity. Our main objective is to dope PK on ZnONPs to reduced zinc-oxide toxicity but increased anti-bacterial and anti-biofilms activity. In present study, we showed that, functions of zinc oxide nanoparticles with pancreatin enzyme (ZnONPs-PK) have anti-bacterial, anti-biofilms, anti-motility and anti-virulence properties against MRSA. Moreover, ZnONPs-PK were more potent to eradicate MRSA than only ZnONPs and PK. Application of the produced nano-composites as treatment on infected swine dermis predominantly reflects the potential treatment property of it. The vancomycin sensitivity of MRSA was significantly increased on application with ZnONPs-PK. Further study revealed cell membrane was the target of the ZnONPs-PK and that leads to oxidative damage of the cells. The produced nanoparticles were found completely non-toxic to human's keratinocytes and lung epithelial cell lines at its bactericidal concentration. Overall, this study emphasizes the potential mechanisms underlying the selective bactericidal properties of ZnONPs-PK against MRSA. This novel nanoparticle strategy may provide the ideal solution for comprehensive management of MRSA and its associated diseases with minimising the use of antibiotics.}, } @article {pmid32172053, year = {2020}, author = {Liu, J and Liu, T and Chen, S and Yu, H and Zhang, Y and Quan, X}, title = {Enhancing anaerobic digestion in anaerobic integrated floating fixed-film activated sludge (An-IFFAS) system using novel electron mediator suspended biofilm carriers.}, journal = {Water research}, volume = {175}, number = {}, pages = {115697}, doi = {10.1016/j.watres.2020.115697}, pmid = {32172053}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; *Electrons ; Methane ; *Sewage ; }, abstract = {Suspended biofilm carriers mediating direct interspecies electron transfer (DIET)-based syntrophic metabolism is a promising strategy to enhance anaerobic digestion and methane production by associating the advantages of conductive suspended biofilm carriers and anaerobic integrated floating fixed-film and activated sludge (An-IFFAS) process. However, the current knowledge of DIET using conductive suspended biofilm carrier is still limited. In this study, novel electron mediator suspended biofilm carriers had been prepared by introducing a series of graphite powders (3 wt%, 5 wt% and 7 wt%) into high-density polyethylene (HDPE), and applied in An-IFFAS reactors. Results showed that An-IFFAS reactors filled with graphite-modified carriers could enhance the degradation of organic matters and the production of methane significantly in comparison with the control reactor filled with conventional HDPE carriers at organic loading rates (OLRs) of 5.9-23.7 kg COD/m[3]/d. Microbial analysis proved that 7 wt% graphite-modified carrier improved approximately 4.2% abundance of Geobacter and 7.3% abundance of electrotrophic methanogens (Methanothrix) that exchange electron via DIET comparing with that of HDPE carriers, respectively. These findings demonstrated that electron mediator suspended biofilm carrier was able to potentially proceed DIET and enhance the efficiency of anaerobic digestion and recover CH4-related energy.}, } @article {pmid32171881, year = {2020}, author = {Cavalcante, LLR and Tedesco, AC and Takahashi, LAU and Curylofo-Zotti, FA and Souza-Gabriel, AE and Corona, SAM}, title = {Conjugate of chitosan nanoparticles with chloroaluminium phthalocyanine: Synthesis, characterization and photoinactivation of Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {30}, number = {}, pages = {101709}, doi = {10.1016/j.pdpdt.2020.101709}, pmid = {32171881}, issn = {1873-1597}, mesh = {Animals ; Biofilms ; Cattle ; *Chitosan ; Indoles ; *Nanoparticles ; Organometallic Compounds ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Streptococcus mutans ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (aPDT) using chloroaluminium phthalocyanine (ClAlPc) has high oxidative power allowing for the control of biofilms, especially when the photosensitizer is administered in an appropriate release vehicle. This study aimed to develop/characterize the ClAlPc encapsulated in chitosan nanoparticles (CSNPs), and evaluate its antimicrobial properties against S. mutans biofilms.

METHODS: CSNPs were prepared by ion gelation, and characterization studies included particle size, polydispersion index (IPd), zeta potential, accelerated stability, absorption spectrum and ClAlPc quantification. The S. mutans biofilms were formed in bovine dentin blocks at 37 °C for 48 h under microaerophilic conditions. 8 μM ClAlPc was combined with a diode laser (InGaAlP) at 660 nm and 100 J/cm[2]. The aPDT toxicity was verified by dark phototoxicity. The antimicrobial activity was verified by CFU/mL and biofilm was analyzed by scanning electron microscopy (SEM). The number of viable bacteria was analyzed by ANOVA and Tukey HSD tests (α = 0.05).

RESULTS: The characterization revealed that the ClAlPc nanoparticles were found in nanometer-scale with adequate photophysical and photochemical properties. The aPDT mediated by ClAlPc + CSNPs nanoconjugate showed a significant reduction in the viability of S. mutans (1log10 CFU/mL) compared to the negative control (PBS, p < 0.05). The aPDT mediated by ClAlPc was similar to PBS (p > 0.05). SEM revealed change in biofilm morphology following the treatment of bacteria with aPDT ClAlPc + CSNPs. Cells were arranged as single or in shorted chains. Irregular shapes of S. mutans were found.

CONCLUSION: ClAlPc nanoparticles are considered stable and aPDT mediated by ClAlPc + CSNPs nanoconjugate was effective against S. mutans biofilm.}, } @article {pmid32171176, year = {2020}, author = {Jin, X and Yang, N and Liu, Y and Guo, F and Liu, H}, title = {Bifunctional cathode using a biofilm and Pt/C catalyst for simultaneous electricity generation and nitrification in microbial fuel cells.}, journal = {Bioresource technology}, volume = {306}, number = {}, pages = {123120}, doi = {10.1016/j.biortech.2020.123120}, pmid = {32171176}, issn = {1873-2976}, abstract = {Biofouling frequently causes catalyst deterioration at the cathode of microbial fuel cells (MFCs). A biofilm-covered Pt/C cathode (BPC) was fabricated via in situ cultivation of a biofilm on a Pt/C cathode (PC) in a dual-chambered MFC, which enables effective removal of NH4[+]-N and copious generation of electricity. Experimental results show 99% NH4[+]-N removal by the nitrifying bacteria that constitute 35.7% of all microorganisms on the BPC and a maximum BPC-MFC power density of 0.97 W/m[2], which is comparable to that of PC-MFCs (0.99 W/m[2]). BPC biofilm size is restricted by the limited amount of organic material in the cathode chamber, which constrains the biomass to less than 0.3 g protein /m[2]. The bifunctional-cathode equipped MFC shows great promise as an energy-saving technology for wastewater treatment in the future.}, } @article {pmid32169780, year = {2020}, author = {Bhatt, L and Chen, L and Guo, J and Klie, RF and Shi, J and Pesavento, RP}, title = {Hydrolyzed Ce(IV) salts limit sucrose-dependent biofilm formation by Streptococcus mutans.}, journal = {Journal of inorganic biochemistry}, volume = {206}, number = {}, pages = {110997}, pmid = {32169780}, issn = {1873-3344}, support = {K08 DE028009/DE/NIDCR NIH HHS/United States ; T32 DE018381/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Cell Proliferation/drug effects ; Cerium/chemistry/*pharmacology ; Dental Caries/drug therapy/metabolism/*pathology ; Humans ; Hydrolysis ; Inhibitory Concentration 50 ; Nanoparticles/*chemistry ; Salts/chemistry/pharmacology ; Streptococcus mutans/*drug effects/physiology ; Sucrose/*metabolism ; }, abstract = {Several studies have focused on the antimicrobial effects of cerium oxide nanoparticles (CeO2-NP) but few have focused on their effects on bacteria under initial biofilm formation conditions. Streptococcus mutans is a prolific biofilm former contributing to dental caries in the presence of fermentable carbohydrates and is a recognized target for therapeutic intervention. CeO2-NP derived solely from Ce(IV) salt hydrolysis were found to reduce adherent bacteria by approximately 40% while commercial dispersions of "bare" CeO2-NP (e.g., 3 nm, 10-20 nm, 30 nm diameter) and Ce(NO3)3·6H2O were either inactive or observed to slightly increase biofilm formation under similar in vitro conditions. Planktonic growth and dispersal assays support a non-bactericidal mode of biofilm inhibition active in the initial phases of S. mutans biofilm production. Human cell proliferation assays suggest only minor effects of hydrolyzed Ce(IV) salts on cellular metabolism at concentrations up to 1 mM Ce, with less observed toxicity compared to equimolar concentrations of AgNO3. The results presented herein have implications in clinical dentistry.}, } @article {pmid32169491, year = {2020}, author = {Hairul Islam, MI and Arokiyaraj, S and Kuralarasan, M and Senthil Kumar, V and Harikrishnan, P and Saravanan, S and Ashok, G and Chellappandian, M and Bharanidharan, R and Muralidaran, S and Thirugnanasambantham, K}, title = {Inhibitory potential of EGCG on Streptococcus mutans biofilm: A new approach to prevent Cariogenesis.}, journal = {Microbial pathogenesis}, volume = {143}, number = {}, pages = {104129}, doi = {10.1016/j.micpath.2020.104129}, pmid = {32169491}, issn = {1096-1208}, mesh = {Biofilms/*drug effects ; Catechin/*analogs & derivatives/pharmacology/therapeutic use ; Dental Caries/microbiology/*prevention & control ; Humans ; Microscopy, Electron, Scanning ; Molecular Docking Simulation ; Streptococcus mutans/*drug effects/ultrastructure ; Tooth/microbiology ; }, abstract = {Dental caries is a common cause for tooth loss and Streptococcus mutans is identified as the etiologic pathogen. This study evaluates the inhibitory potential of Epigallocatechin gallate (EGCG) on S.mutans glucansucrase enzyme and its biofilm. Glucansucrase binding and the inhibitory potential of EGCG was validated using AutoDock tool and enzyme inhibitory assay. Biofilm inhibitory potential was also confirmed using Scanning Electron Microscopic (SEM) analysis in human tooth samples. Molecular docking revealed that EGCG interacted with GLU 515 and TRP 517 amino acids and binds to glucansucrase. SEM analysis revealed inhibition of S.mutans biofilm by various concentrations of EGCG on surfaces of tooth samples. Bioinformatics and biological assays confirmed that EGCG potentially binds to the S. mutans glucansucrase and inhibits its enzymatic activity. Enzymatic inhibition of glucansucrase attenuated biofilm formation potential of S. mutans on tooth surface. Thus, we conclude that EGCG inhibitory potential of S. mutans biofilm on the tooth surface is a novel approach in prevention of dental caries.}, } @article {pmid32169075, year = {2020}, author = {Wannigama, DL and Hurst, C and Hongsing, P and Pearson, L and Saethang, T and Chantaravisoot, N and Singkham-In, U and Luk-In, S and Storer, RJ and Chatsuwan, T}, title = {A rapid and simple method for routine determination of antibiotic sensitivity to biofilm populations of Pseudomonas aeruginosa.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {19}, number = {1}, pages = {8}, pmid = {32169075}, issn = {1476-0711}, support = {No. 39 (2/61)//Chulalongkorn University/ ; No. 39 (2/61)//Faculty of Medicine, Chulalongkorn University/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests/*methods ; *Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {Treatment of infections by Pseudomonas aeruginosa forming biofilms after antimicrobial testing on planktonic bacteria can result in substantial failure. Therefore, we offer a robust and simple experimental platform to test the impact of antimicrobials on biofilms. Antibiotic response patterns varied uniquely within biofilm formation capacity and minimal biofilm eradication concentrations (MBECs) has a significantly better discriminatory power than minimum inhibitory concentrations (MICs) to differentiate the overall efficiency of antibiotics to eradicate biofilm. Our resazurin-based 96-well-plate platform is able to emulate bacterial responses to antibiotics under biofilm conditions in a fast, simple, and cost-effective screening method adaptable to automation, and warrants trials in the clinic.}, } @article {pmid32167817, year = {2020}, author = {Azevedo, MM and Lisboa, C and Cobrado, L and Pina-Vaz, C and Rodrigues, A}, title = {Hard-to-heal wounds, biofilm and wound healing: an intricate interrelationship.}, journal = {British journal of nursing (Mark Allen Publishing)}, volume = {29}, number = {5}, pages = {S6-S13}, doi = {10.12968/bjon.2020.29.5.S6}, pmid = {32167817}, issn = {0966-0461}, mesh = {Anti-Infective Agents, Local/*therapeutic use ; *Biofilms/drug effects/growth & development ; Humans ; Wound Healing/*physiology ; *Wound Infection/microbiology/prevention & control/therapy ; }, abstract = {Hard-to-heal wounds are a major public health problem that incur high economic costs. A major source of morbidity, they can have an overwhelming impact on patients, caregivers and society. In contrast to acute wound healing, which follows an 'orderly and timely reparative process', the healing of hard-to-heal wounds is delayed because the usual biological progression is interrupted. This article discusses hard-to-heal wounds, the impact they have on patients and healthcare systems, and how biofilms and other factors affect the wound-healing process. Controlling and preventing infection is of utmost importance for normal wound healing. Rational use of anti-infectious agents is crucial and is particularly relevant in the context of rising healthcare costs. Knowledge of the complex relationship between hard-to-heal wounds, biofilm formation and wound healing is vital for efficient management of hard-to-heal wounds.}, } @article {pmid32167434, year = {2020}, author = {Khan, F and Lee, JW and Pham, DNT and Khan, MM and Park, SK and Shin, IS and Kim, YM}, title = {Antibiofilm Action of ZnO, SnO2 and CeO2 Nanoparticles Towards Grampositive Biofilm Forming Pathogenic Bacteria.}, journal = {Recent patents on nanotechnology}, volume = {14}, number = {3}, pages = {239-249}, doi = {10.2174/1872210514666200313121953}, pmid = {32167434}, issn = {2212-4020}, mesh = {Biofilms/*drug effects ; Cerium/*pharmacology ; Humans ; Listeria monocytogenes/drug effects/*physiology/ultrastructure ; Metal Nanoparticles/*chemistry/ultrastructure ; Staphylococcus aureus/drug effects/*physiology/ultrastructure ; Tin Compounds/*pharmacology ; Toxicity Tests ; Zinc Oxide/*pharmacology ; }, abstract = {BACKGROUND: The ability to form biofilm and produce several virulence factors has caused numerous human pathogens to become tremendously resistant towards traditional antibiotic treatments, thus, new alternative strategies are urgently in demand. One of the strategies that have recently been developed involves the application of metallic Nanoparticles (NPs). Up to the present, promising results in terms of antimicrobial and antibiofilm activities have been observed in a wide range of metal NPs.

METHODS: The present study has selected three metal oxides such as ZnO, SnO2 and CeO2 NPs to comparatively investigate their antibiofilm and antibacterial properties against two Gram-positive human pathogens, which are Listeria monocytogenes and Staphylococcus aureus.

RESULTS: The anti-biofilm activities of ZnO, SnO2 and CeO2 NPs against S. aureus and L. monocytogenes were assayed by crystal violet staining and confirmed by microscopic visualization using SEM. The synthesis of amyloid protein by S. aureus and exopolysaccharide by L. monocytogenes in the presence of ZnO, SnO2 and CeO2 NPs was evaluated by Congo red assay.

DISCUSSION: Results have shown that ZnO, SnO2 and CeO2 NPs effectively inhibited biofilm formation of both L. monocytogenes and S. aureus. The microscopic analysis also confirmed the antibiofilm activity of these NPs. It was also found that only ZnO NPs inhibited cell growth as well as the production of amyloid protein in S. aureus.

CONCLUSION: Overall, these results indicated that ZnO, SnO2 and CeO2 NPs can be considered as potential agents for treating the infections caused by L. monocytogenes and S. aureus, especially those associated with biofilm formation. Based on the present study, further studies are required to understand their mechanisms at both phenotypic and molecular levels, as well as their in vivo cytotoxicity, thereby enabling the applications of these metal oxide NPs in biomedical fields and food industry.}, } @article {pmid32166519, year = {2020}, author = {Ford, N and Chopp, D}, title = {A Dimensionally Reduced Model of Biofilm Growth Within a Flow Cell.}, journal = {Bulletin of mathematical biology}, volume = {82}, number = {3}, pages = {40}, doi = {10.1007/s11538-020-00715-0}, pmid = {32166519}, issn = {1522-9602}, support = {DMS-1547394//National Science Foundation/International ; }, mesh = {Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Biomass ; Computer Simulation ; Hydrodynamics ; Mathematical Concepts ; *Models, Biological ; }, abstract = {Biofilms are colonies of bacteria attached to surfaces. They play a critical role in many engineering and medical applications. Scientists study biofilm growth in flow cells but often have limited direct knowledge of the environmental conditions in the apparatus. Using fully resolved, numerical simulations to estimate conditions within a flow cell is computationally expensive. In this paper, we use asymptotic analysis to create a simulation of a biofilm system that has one growth-limiting substrate, and we show that this method runs quickly while maintaining similar accuracy to prior models. These equations can provide a better understanding of the environmental conditions in experiments and can establish the boundary conditions for further smaller-scale numerical simulations.}, } @article {pmid32165225, year = {2020}, author = {Dian Permana, A and Mir, M and Utomo, E and Donnelly, RF}, title = {WITHDRAWN: Bacterially sensitive nanoparticle-based dissolving microneedles of doxycycline for enhanced treatment of bacterial biofilm skin infection: A proof of concept study.}, journal = {International journal of pharmaceutics}, volume = {}, number = {}, pages = {119220}, doi = {10.1016/j.ijpharm.2020.119220}, pmid = {32165225}, issn = {1873-3476}, } @article {pmid32164475, year = {2022}, author = {Faria, JB and Santiago, MB and Silva, CB and Geraldo-Martins, VR and Nogueira, RD}, title = {Development of Streptococcus mutans biofilm in the presence of human colostrum and 3'-sialyllactose.}, journal = {The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians}, volume = {35}, number = {4}, pages = {630-635}, doi = {10.1080/14767058.2020.1730321}, pmid = {32164475}, issn = {1476-4954}, mesh = {Biofilms ; *Colostrum ; Female ; Humans ; Infant, Newborn ; Oligosaccharides ; Pregnancy ; Saliva ; *Streptococcus mutans ; }, abstract = {AIM: To evaluate the initial adhesion and formation of Streptococcus mutans biofilm in vitro in the presence of saliva, human colostrum and 3'-sialyllactose.

METHODS: Human colostrum and salivas were collected from 30 mothers and newborn postpartum. Eighteen hours culture of S. mutans was treated with colostrum or 3'-sialyllactose in three different moments: before, during, and after 24 h from the microbial inoculation. Salivas were also tested in conjunction with colostrum. The assays were realized in sterile 96-well flat-bottom microtiter plates for 24 h. The biofilms were fixed, washed, stained with crystal violet, and extracted. Absorbance was measured to evaluate biofilm growth mass.

RESULTS: Colostrum applied after and during the inoculation decreased biofilm formation when compared with the control (p < .05). The presence of saliva increased the biofilm biomass (p < .05). The application of 3'-sialyllactose reduced biofilm formation independently of moments of application (p < .05).

CONCLUSION: Saliva contributed to the proliferation of biofilm and colostrum did not prevent the initial adhesion, but interfered in the accumulation and development of microorganisms in biofilms. 3'-sialyllactose significantly decreased biofilm formation. This information expands the importance of colostrum as a potent oral antimicrobial biofluid.}, } @article {pmid32161578, year = {2020}, author = {Jordana-Lluch, E and Garcia, V and Kingdon, ADH and Singh, N and Alexander, C and Williams, P and Hardie, KR}, title = {A Simple Polymicrobial Biofilm Keratinocyte Colonization Model for Exploring Interactions Between Commensals, Pathogens and Antimicrobials.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {291}, pmid = {32161578}, issn = {1664-302X}, support = {MR/N010477/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Skin offers protection against external insults, with the skin microbiota playing a crucial defensive role against pathogens that gain access when the skin barrier is breached. Linkages between skin microbes, biofilms and disease have not been well established although single-species biofilm formation by skin microbiota in vitro has been extensively studied. Consequently, the purpose of this work was to optimize and validate a simple polymicrobial biofilm keratinocyte model for investigating commensal, pathogen and keratinocyte interactions and for evaluating therapeutic agents or health promoting interventions. The model incorporates the commensals (Staphylococcus epidermidis and Micrococcus luteus) and pathogens (Staphylococcus aureus and Pseudomonas aeruginosa) which form robust polymicrobial biofilms on immortalized keratinocytes (HaCat cells). We observed that the commensals reduce the damage caused to the keratinocyte monolayer by either pathogen. When the commensals were combined with P. aeruginosa and S. aureus, much thinner biofilms were observed than those formed by the pathogens alone. When P. aeruginosa was inoculated with S. epidermidis in the presence or absence of M. luteus, the commensals formed a layer between the keratinocytes and pathogen. Although S. aureus completely inhibited the growth of M. luteus in dual-species biofilms, inclusion of S. epidermidis in triple or quadruple species biofilms, enabled M. luteus to retain viability. Using this polymicrobial biofilm keratinocyte model, we demonstrate that a quorum sensing (QS) deficient S. aureus agr mutant, in contrast to the parent, failed to damage the keratinocyte monolayer unless supplied with the exogenous cognate autoinducing peptide. In addition, we show that treatment of the polymicrobial keratinocyte model with nanoparticles containing an inhibitor of the PQS QS system reduced biofilm thickness and P. aeruginosa localization in mono- and polymicrobial biofilms.}, } @article {pmid32160744, year = {2020}, author = {Zhang, X and Yuan, H and Wang, Y and Guan, L and Zeng, Z and Jiang, Z and Zhang, X}, title = {Cell Surface Energy Affects the Structure of Microalgal Biofilm.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {36}, number = {12}, pages = {3057-3063}, doi = {10.1021/acs.langmuir.0c00274}, pmid = {32160744}, issn = {1520-5827}, mesh = {Biofilms ; Biomass ; Biotechnology ; *Chlorella ; *Microalgae ; }, abstract = {Microalgae biofilm-based culture systems have wide applications in environmental engineering and biotechnology. Biofilm structure is critical for the transport of nutrients, gas, and signaling molecules in a microalgal biofilm. This work aims to understand the influence of cell surface energy (SE) on the microalgal biofilm structure. Three microalgae species were used as model cells in the study: Chlorella sp., Nannochloris oculata, and Chlorella pyrenoidosa. First, by mediating biofilm culture conditions, we obtained Chlorella sp. cells with SEs of 40.4 ± 1.5, 44.7 ± 1.0, and 62. 7 ± 1.2 mJ/m[2], N. oculata cells with SEs of 47.7 ± 0.5, 41.1 ± 1.0, and 62.6 ± 1.2 mJ/m[2], and C. pyrenoidosa cells with SEs of 64.0 ± 0.6, 62.1 ± 0.7, and 62.8 ± 0.6 mJ/m[2]. Then, based on the characterizations of biofilm structures, we found that cell SE can significantly affect the microalgae biofilm structure. When the cell SEs ranged from 40 to 50 mJ/m[2], the microalgae cells formed heterogeneous biofilms with a large number of open voids, and the biofilm porosity was higher than 20%. Alternatively, when the cell SEs ranged from 50 to 65 mJ/m[2], the cells formed a flat, homogeneous biofilm with the porosity lower than 20%. Finally, the influencing mechanism of cell SE on biofilm structure was interpreted based on the thermodynamic theory via analyzing the co-adhesion energy between cells. The study has important implications in understanding factors that influence the biofilm structures.}, } @article {pmid32160088, year = {2020}, author = {Suleman, L and Purcell, L and Thomas, H and Westgate, S}, title = {Use of internally validated in vitro biofilm models to assess antibiofilm performance of silver-containing gelling fibre dressings.}, journal = {Journal of wound care}, volume = {29}, number = {3}, pages = {154-161}, doi = {10.12968/jowc.2020.29.3.154}, pmid = {32160088}, issn = {0969-0700}, mesh = {*Bandages ; Biofilms/*drug effects ; Candida albicans/drug effects ; Gels ; Humans ; Models, Biological ; Pseudomonas aeruginosa/drug effects ; Reproducibility of Results ; Silver/administration & dosage/pharmacology/*therapeutic use ; Staphylococcus aureus/drug effects ; Wound Healing ; Wound Infection/*drug therapy/microbiology/nursing ; }, abstract = {OBJECTIVE: To assess the efficacy of five silver-containing gelling fibre wound dressings against single-species and multispecies biofilms using internally validated, UKAS-accredited in vitro test models.

METHOD: Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans single- and multispecies biofilms were cultured using Centres for Disease Control (CDC) biofilm reactors and colony drip flow reactors (CDFR). Following a 72 hour incubation period, the substrates on which biofilms were grown were rinsed to remove planktonic microorganisms and then challenged with fully hydrated silver-containing gelling fibre wound dressings. Following dressing application for 24 or 72 hours, remaining viable organisms from the treated biofilms were quantified.

RESULTS: In single-species in vitro models, all five antimicrobial dressings were effective in eradicating Staphylococcus aureus and Pseudomonas aeruginosa biofilm bacteria. However, only one of the five dressings (Hydrofiber technology with combination antibiofilm/antimicrobial technology) was able to eradicate the more tolerant single-species Candida albicans biofilm. In a more complex and stringent CDFR biofilm model, the hydrofiber dressing with combined antibiofilm/antimicrobial technology was the only dressing that was able to eradicate multispecies biofilms such that no viable organisms were recovered.

CONCLUSION: Given the detrimental effects of biofilm on wound healing, stringent in vitro biofilm models are increasingly required to investigate the efficacy of antimicrobial dressings. Using accredited in vitro biofilm models of increasing complexity, differentiation in the performance of dressings with combined antibiofilm/antimicrobial technology against those with antimicrobial properties alone, was demonstrated.}, } @article {pmid32159509, year = {2020}, author = {Ray, S and Da Costa, R and Thakur, S and Nandi, D}, title = {Salmonella Typhimurium encoded cold shock protein E is essential for motility and biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {5}, pages = {460-473}, doi = {10.1099/mic.0.000900}, pmid = {32159509}, issn = {1465-2080}, mesh = {Bacterial Proteins/genetics/*physiology ; Biofilms/*growth & development ; Biological Phenomena ; Cold Shock Proteins and Peptides/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Movement ; Mutation ; Salmonella typhimurium/*genetics/*physiology/ultrastructure ; Up-Regulation ; }, abstract = {The ability of bacteria to form biofilms increases their survival under adverse environmental conditions. Biofilms have enormous medical and environmental impact; consequently, the factors that influence biofilm formation are an important area of study. In this investigation, the roles of two cold shock proteins (CSP) during biofilm formation were investigated in Salmonella Typhimurium, which is a major foodborne pathogen. Among all CSP transcripts studied, the expression of cspE (STM14_0732) was higher during biofilm growth. The cspE deletion strain (ΔcspE) did not form biofilms on a cholesterol coated glass surface; however, complementation with WT cspE, but not the F30V mutant, was able to rescue this phenotype. Transcript levels of other CSPs demonstrated up-regulation of cspA (STM14_4399) in ΔcspE. The cspA deletion strain (ΔcspA) did not affect biofilm formation; however, ΔcspEΔcspA exhibited higher biofilm formation compared to ΔcspE. Most likely, the higher cspA amounts in ΔcspE reduced biofilm formation, which was corroborated using cspA over-expression studies. Further functional studies revealed that ΔcspE and ΔcspEΔcspA exhibited slow swimming but no swarming motility. Although cspA over-expression did not affect motility, cspE complementation restored the swarming motility of ΔcspE. The transcript levels of the major genes involved in motility in ΔcspE demonstrated lower expression of the class III (fliC, motA, cheY), but not class I (flhD) or class II (fliA, fliL), flagellar regulon genes. Overall, this study has identified the interplay of two CSPs in regulating two biological processes: CspE is essential for motility in a CspA-independent manner whereas biofilm formation is CspA-dependent.}, } @article {pmid32159447, year = {2020}, author = {Hosseini, M and Shapouri Moghaddam, A and Derakhshan, S and Hashemipour, SMA and Hadadi-Fishani, M and Pirouzi, A and Khaledi, A}, title = {Correlation Between Biofilm Formation and Antibiotic Resistance in MRSA and MSSA Isolated from Clinical Samples in Iran: A Systematic Review and Meta-Analysis.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {9}, pages = {1071-1080}, doi = {10.1089/mdr.2020.0001}, pmid = {32159447}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Coagulase/*genetics/metabolism ; Gene Expression ; Humans ; Iran/epidemiology ; Methicillin/*pharmacology ; Methicillin Resistance/*genetics ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/growth & development ; Microbial Sensitivity Tests ; Prevalence ; Staphylococcal Infections/drug therapy/epidemiology/microbiology ; Staphylococcus aureus/drug effects/*genetics/growth & development ; }, abstract = {Objectives: This study aimed at reviewing the correlation between biofilm formation and antibiotic resistance in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates. Materials and Methods: This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocols. The literature search was conducted in PubMed, Web of Science (ISI), and Scopus databases. Combinations of Mesh terms such as "biofilms" OR "biofilm formation," AND "Drug Resistance" OR "Antimicrobial Drug Resistance" OR "Antibiotic Resistance" AND "Staphylococcus aureus" OR "Methicillin-resistant Staphylococcus aureus" or "MRSA" AND "Methicillin-sensitive Staphylococcus aureus" OR "MSSA" AND "biofilm-related genes" AND "Prevalence" AND "Iran" were searched. Two reviewers independently searched the databases. Analyses were performed in Comprehensive Meta-Analysis software. The random-effects model was used to obtain the combined prevalence with a 95% confidence interval (CI). Results: The combined prevalence of MRSA retrieved from Iranian clinical samples was 48.3% (95% CI: 40.8-55.9). The pooled rate of biofilm formation in MRSA strains was reported as 80.9% (95% CI: 67.8-89.4). Overall, 52.9%, 45.3%, and 22.5% of MRSA isolates were strong, moderate, and weak biofilm producers, respectively. The highest frequency of biofilm-related genes was observed for icaD gene (67.7%) followed by clfA gene with a frequency of 64.7%. Among seven studies that addressed the relationship between biofilm formation and antibiotic resistance, six reported positive associations. Conclusions: Regarding the MRSA strains, they had a significantly higher ability of biofilm formation than MSSA strains; therefore, preventive measures against infections caused by them are required.}, } @article {pmid32156542, year = {2020}, author = {Wang, Z and Yang, Q and Wang, X and Li, R and Qiao, H and Ma, P and Sun, Q and Zhang, H}, title = {Antibacterial activity of xanthan-oligosaccharide against Staphylococcus aureus via targeting biofilm and cell membrane.}, journal = {International journal of biological macromolecules}, volume = {153}, number = {}, pages = {539-544}, doi = {10.1016/j.ijbiomac.2020.03.044}, pmid = {32156542}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/*metabolism ; *Drug Delivery Systems ; Oligosaccharides/chemistry/*pharmacology ; Polysaccharides, Bacterial/*chemistry ; Staphylococcus aureus/*physiology ; }, abstract = {Previously, an antioxidant xanthan-oligosaccharide (LW-XG) was successfully produced via bio-degradation of commercial xanthan. In present work, the antibacterial activity and mechanism action of LW-XG against Staphylococcus aureus were studied. Inhibition zone of LW-XG in agar diffusion test was evident and its minimal inhibitory concentration (MIC) against S. aureus was 0.63 mg/mL. Inhibitory mechanism investigation showed that LW-XG increased the cell membrane permeability of S. aureus. Meanwhile, we found that LW-XG could retard the formation of S. aureus biofilm and lower the transcriptional levels of genes (fnbA, fnbB and clfB) related to biofilm formation. Furthermore, LW-XG decreased the Ca[2+]-Mg[2+]-ATPase activity on S. aureus cell membrane and promoted the accumulation of calcium ions in cytoplasm. Overall, LW-XG could inhibit the growth of S. aureus and be regarded as a promising antibacterial substitute in food and pharmaceutical industries.}, } @article {pmid32156305, year = {2020}, author = {Kurakado, S and Chiba, R and Sato, C and Matsumoto, Y and Sugita, T}, title = {N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine, a zinc chelator, inhibits biofilm and hyphal formation in Trichosporon asahii.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {142}, pmid = {32156305}, issn = {1756-0500}, support = {JP18fk0108045//Japan Agency for Medical Research and Development/ ; }, mesh = {Biofilms/*drug effects ; Chelating Agents/*pharmacology ; Ethylenediamines/*pharmacology ; Hyphae/drug effects/*growth & development ; Trichosporon/drug effects/*physiology ; Zinc/*chemistry ; }, abstract = {OBJECTIVE: Trichosporon asahii is the major causative fungus of disseminated or deep-seated trichosporonosis and forms a biofilm on medical devices. Biofilm formation leads to antifungal drug resistance, so biofilm-related infections are relatively difficult to treat and infected devices often require surgical removal. Therefore, prevention of biofilm formation is important in clinical settings. In this study, to identify metal cations that affect biofilm formation, we evaluated the effects of cation chelators on biofilm formation in T. asahii.

RESULTS: We evaluated the effect of cation chelators on biofilm formation, since microorganisms must assimilate essential nutrients from their hosts to form and maintain biofilms. The inhibition by N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) was greater than those by other cation chelators, such as deferoxamine, triethylenetetramine, and ethylenediaminetetraacetic acid. The inhibitory effect of TPEN was suppressed by the addition of zinc. TPEN also inhibited T. asahii hyphal formation, which is related to biofilm formation, and the inhibition was suppressed by the addition of zinc. These results suggest that zinc is essential for biofilm formation and hyphal formation. Thus, zinc chelators have the potential to be developed into a new treatment for biofilm-related infection caused by T. asahii.}, } @article {pmid32155005, year = {2020}, author = {Shipitsyna, IV and Osipova, EV and Ovchinnikov, EN and Leonchuk, DS}, title = {[Dependence of biofilm-forming ability on the antibiotic sensitivity of Pseudomonas aeruginosa clinical strains isolated from patients with chronic osteomyelitis.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {65}, number = {1}, pages = {37-41}, doi = {10.18821/0869-2084-2020-65-1-37-41}, pmid = {32155005}, issn = {0869-2084}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Carbapenems ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Osteomyelitis/*microbiology ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*drug effects/*growth & development ; }, abstract = {Due to the spreading highly resistant strains among clinically significant P. aeruginosa clones, it becomes necessary to prescribe antibiotics not only taking into account the knowledge of sensitivity spectrum of a particular isolate but the data of microorganism biofilm activity as well. To study the dependence of biofilm-forming ability on the sensitivity to antibacterial preparations of P. aeruginosa clinical strains, isolated from patients with chronic osteomyelitis. 36 patients above 18 with chronic osteomyelitis of long tubular bones who were treated in the center of purulent osteology took part in the experiment. Object of the study - material isolated from wounds, fistulas, as well as from inflammatory foci. The sensitivity of isolated microorganisms to 10 antibiotics was analyzed: Piperacillin/Tazobactam, Imipenem, Meropenem, Aztreonam, Amikacin, Ciprofloxacin, Ceftriaxone, Ceftazidime, Cefotaxime, Cefepime. High- and medium-adhesive strains accounted for 86,1 % among P. aeruginosa clinical isolates, obtained from the wounds of patients with chronic osteomyelitis of long tubular bones. Highly adhesive strains are resistant to a wide range of antibacterial preparations used clinically. Penicillins were the most effective preparations when analyzing antibioticograms obtained for highly adhesive strains, for medium adhesive strains - penicillins, aminoglycosides and carbapenems, for low adhesive ones - aminoglycosides, penicillins, carbapenems, monobactams, quinolones. P. aeruginosa multi-resistance is a serious problem in the treatment of patients with chronic osteomyelitis. Spreading antibiotic-resistant strains of P. aeruginosa is associated with the presence of bacteria in the biofilm. Since adhesion is the first step in the biofilm formation, it is important to identify strains having high adhesive ability timely.}, } @article {pmid32154728, year = {2020}, author = {Ma, J and Lin, W and Xu, L and Liu, S and Xue, W and Chen, S}, title = {Resistance to Long-Term Bacterial Biofilm Formation Based on Hydrolysis-Induced Zwitterion Material with Biodegradable and Self-Healing Properties.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {36}, number = {12}, pages = {3251-3259}, doi = {10.1021/acs.langmuir.0c00006}, pmid = {32154728}, issn = {1520-5827}, mesh = {Adsorption ; *Biocompatible Materials/toxicity ; Biofilms ; Hydrolysis ; *Quartz Crystal Microbalance Techniques ; Surface Properties ; }, abstract = {Long-term resistance of biomaterials to the bacterial biofilm formation without antibiotic or biocide is highly demanded for biomedical applications. In this work, a novel biodegradable biomaterial with excellent capability to prevent long-term bacterial biofilm formation is prepared by the following two steps. Ethylcarboxybetaine ester analogue methacrylate (ECBEMA), poly(ethylene glycol) monomethacrylate (PEGMA), and 3-methacryloxypropyletris(trimethylsiloxy)silane (TRIS) were copolymerized to obtain p(ECBEMA-PEGMA-TRIS) (PEPT). Then, PEPT was cross-linked by isocyanate-terminated polylactic acid (IPDI-PLA-IPDI) to obtain the final PEPTx-PLAy (x and y are the number-average molecular weights (Mn) of PEPT and PLA, respectively) with optimal mechanical strength and adjustable surface regeneration rate. Static contact angle measurement, protein adsorption measurement, and attenuated total reflectance infrared (ATR-IR) results show that the PEPT19800-PLA800 film surface can generate a zwitterionic layer to resist nonspecific protein adsorption after surface hydrolysis. Quartz crystal microbalance with dissipation (QCM-D) results indicates that the PEPT19800-PLA800 film can undergo gradual degradation of the surface layer at the lowest swelling rate. Particularly, this material can efficiently resist the bacterial biofilm formation of both Gram-positive bacteria and Gram-negative bacteria over 14 and 6 days, respectively. Moreover, the material also shows an ideal self-healing feature to adapt to harsh conditions. Thus, this nonfouling material shows great potential in biomedical applications and marine antifouling coatings without antibiotic or biocide.}, } @article {pmid32150327, year = {2020}, author = {Mirzaei, R and Mohammadzadeh, R and Alikhani, MY and Shokri Moghadam, M and Karampoor, S and Kazemi, S and Barfipoursalar, A and Yousefimashouf, R}, title = {The biofilm-associated bacterial infections unrelated to indwelling devices.}, journal = {IUBMB life}, volume = {72}, number = {7}, pages = {1271-1285}, doi = {10.1002/iub.2266}, pmid = {32150327}, issn = {1521-6551}, mesh = {Animals ; Bacterial Infections/*microbiology ; Biofilms/*growth & development ; Catheters, Indwelling ; Humans ; }, abstract = {Biofilms are microbial communities established in the self-produced extracellular substances that include up to 80% of associated microbial infections. During biofilm formation, bacterial cells shift from the planktonic forms to aggregated forms surrounded by an extracellular polymeric substance. The bacterial biofilm shows resistance against immune reactions as well as antibiotics and is potentially able to cause disorders by both device-related and nondevice-related infections. The nondevice-related bacterial biofilm infections include dental plaque, urinary tract infections, cystic fibrosis, otitis media, infective endocarditis, tonsillitis, periodontitis, necrotizing fasciitis, osteomyelitis, infectious kidney stones, and chronic inflammatory diseases. In this review, we will summarize and examine the literature about bacterial biofilm infections unrelated to indwelling devices.}, } @article {pmid32149585, year = {2021}, author = {Sun, Y and Huang, L and Lai, C and Li, H and Yang, P}, title = {Removal of organics from shale gas fracturing flowback fluid using expanded granular sludge bed and moving bed biofilm reactor.}, journal = {Environmental technology}, volume = {42}, number = {24}, pages = {3736-3746}, doi = {10.1080/09593330.2020.1739750}, pmid = {32149585}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Natural Gas ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {Shale gas fracturing flowback fluid contains various degradation difficulty organic compounds after hydraulic fracturing. A hybrid treatment method was developed for treating flowback and produced water (FPW) using pre-treatment (NaClO) followed by the expanded granular sludge bed (EGSB) and moving bed biofilm reactor (MBBR). Gas chromatography-mass spectrometry (GC-MS) was employed to detect organic composition in the FPW, the pre-treated FPW, EGSB and MBBR effluent. FPW had high chemical oxygen demand (COD) (3278 mg/L) and the majority of organic compounds in the FPW composed of alkanes and heteroatomic compounds with polymers and polarity. 20% COD removal was achieved after adding 5 g/L of NaClO in FPW (pH = 7, stirring for 20 mins) as pre-treatment and > C30 alkanes in FPW were decomposed a lot in the pre-treatment process. The pre-treated FPW was diluted (volumetric ratio of 20%/50%) with synthetic wastewater/pure water. In the final stage of operation, Cl[-] and COD concentration of influent to EGSB-MBBR system was around 7000 ± 100 mg/L and 3000 mg/L. EGSB-MBBR system achieved 93.84% COD removal rate, in which EGSB dominated COD removal (>80%). According to the GC-MS results, EGSB had an increase of C11-C30 compounds and a decrease of less C1-C10 content due to the consumption of > C30 compounds and low molecular weight (LWM) compounds. Meanwhile, aerobic microorganisms in MBBR metabolized LWM organics which contributed a lot to the COD removal (25.06∼68. 22%). The results indicated that the pre-treatment and biological EGSB-MBBR system could be an efficient option used for FPW treating.}, } @article {pmid32146497, year = {2020}, author = {Karuppiah, V and Thirunanasambandham, R}, title = {Quebrachitol from Rhizophora mucronata inhibits biofilm formation and virulence production in Staphylococcus epidermidis by impairment of initial attachment and intercellular adhesion.}, journal = {Archives of microbiology}, volume = {202}, number = {6}, pages = {1327-1340}, pmid = {32146497}, issn = {1432-072X}, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Inositol/*analogs & derivatives/pharmacology ; Microscopy, Electron, Scanning ; Plant Extracts/*pharmacology ; Rhizophoraceae/chemistry ; Staphylococcus epidermidis/*drug effects/metabolism/physiology/ultrastructure ; Virulence/drug effects ; }, abstract = {Staphylococcus epidermidis is well recognized nosocomial pathogen in clinical settings for their implants associated infections. Biofilm and virulence production executes a S. epidermidis pathogenesis against host. Hence, interfering of biofilm formation has become an auspicious to control the pathogenesis of S. epidermidis. The present study evaluates antibiofilm potential of Rhizophora mucronata against S. epidermidis biofilms. Rhizophora mucronata leaves extract significantly inhibited the biofilm formation and quebrachitol was identified as an active compound responsible for the biofilm inhibition. Quebrachitol significantly inhibited biofilm formation at concentration dependent manner without exhibit non-bactericidal property. And, quebrachitol reduced the biofilm building components such as exopolysaccharides, lipase and proteins production. Confocal laser scanning microscopic studies obtained quebrachitol surface independent biofilm efficacy against S. epidermidis. Notably, quebrachitol significantly reduced S. epidermidis adherence on biotic (coated with type I collagen and fibrinogen) and abiotic (hydrophobic and hydrophilic) surfaces. Addition of quebrachitol inhibits autolysis mediated initial attachment and accumulation associated aggregation process. Moreover, quebrachitol significantly reduced the hydrolases virulence production which supports S. epidermidis invasion into the host. Furthermore, gene expression analysis revealed the ability of quebrachitol to downregulate the virulence genes expression which are mainly involved in biofilm formation and virulence production. The results obtained from the present study suggest that quebrachitol as an ideal candidate for the therapeutic action against S. epidermidis pathogenesis.}, } @article {pmid32145619, year = {2020}, author = {Benjedim, S and Romero-Cano, LA and Pérez-Cadenas, AF and Bautista-Toledo, MI and Lotfi, EM and Carrasco-Marín, F}, title = {Removal of emerging pollutants present in water using an E-coli biofilm supported onto activated carbons prepared from argan wastes: Adsorption studies in batch and fixed bed.}, journal = {The Science of the total environment}, volume = {720}, number = {}, pages = {137491}, doi = {10.1016/j.scitotenv.2020.137491}, pmid = {32145619}, issn = {1879-1026}, mesh = {Adsorption ; Biofilms ; Charcoal ; Escherichia coli ; Hydrogen-Ion Concentration ; Kinetics ; Water ; Water Pollutants, Chemical/*isolation & purification ; }, abstract = {In order to improve the removal rates of paracetamol and amoxicillin present in water, activated carbons prepared from argan waste were designed as a support for a biofilm-based on E. coli yielding microporous materials with high surface areas, in such a way that the biofilm support could be made homogeneously on the internal and external surface of the material. Adsorption studies without the presence of the biofilm showed rapid kinetics with adsorption constants kPCT = 0.06 and kAMX = 0.007 min[-1]. The adsorption isotherms could be described by the Langmuir isotherm model reaching a maximum adsorption capacity of qPCT = 502 and qAMX = 319 mg g[-1]. In contrast, the results obtained for the materials that support the biofilm showed slow kinetics (kPCT = 0.007 and kAMX = 0.003 min[-1]) and a remarkable change in the shape of the adsorption isotherms, since the experimental data are better represented by a combined Langmuir-Freundlich model, in which three important stages are observed: (i) In a first stage, adsorption is carried out in those spaces available after supporting the biofilm in the surface of the ACs. Once these spaces have been saturated, a second stage (ii) is present with an exponential behavior typical of the Freundlich isotherm, attributed to the adsorption of the pharmaceutical compounds in the biofilm, Finally a third stage is observed (iii) where the asymptotic behavior typical of the saturation of the adsorbent according to the Langmuir model is already appreciated (qPCT = 504 and qAMX = 465 mg g[-1]).}, } @article {pmid32145556, year = {2020}, author = {Bighiu, MA and Höss, S and Traunspurger, W and Kahlert, M and Goedkoop, W}, title = {Limited effects of pesticides on stream macroinvertebrates, biofilm nematodes, and algae in intensive agricultural landscapes in Sweden.}, journal = {Water research}, volume = {174}, number = {}, pages = {115640}, doi = {10.1016/j.watres.2020.115640}, pmid = {32145556}, issn = {1879-2448}, mesh = {Agriculture ; Animals ; Biofilms ; Environmental Monitoring ; Invertebrates ; *Nematoda ; *Pesticides ; Rivers ; Sweden ; *Water Pollutants, Chemical ; }, abstract = {Pesticides are frequently detected in surface waters, sometimes at levels exceeding ecotoxicological guidelines. We screened for almost 100 pesticides in 32 streams from intense agricultural areas in Southern Sweden, in concert with water chemistry parameters. In addition, we investigated the communities of benthic macroinvertebrates, biofilm nematodes and algae and calculated multiple bioassessment metrics. The number of pesticides found in each stream ranged between 2 and 52, but the sum of Toxic Units (ΣTU) for the mixtures was generally low, and exceeded the European Uniform Principles only in a single sample for algae and in 2% of the samples for Daphnia. Only nematode communities were significantly correlated with the ΣTU, potentially due to their higher pesticide exposure in biofilms. Diatom metrics showed that most streams were impacted by eutrophication and macroinvertebrate metrics showed good status in most streams, whereas the SPEARpesticides (SPEcies At Risk) index, specifically designed to indicate pesticide effects, showed that about half of the samples were at risk. Interestingly, SPEARpesticides was not correlated to ΣTUDaphnia, and this discrepancy suggests that redefining the boundaries for quality classes might be necessary for this index. Moreover, SPEARpesticides was positively correlated with the commonly used macroinvertebrate index ASPT, although disparate results were found for several streams. We argue that this questions the scaling of both metrics and the specificity of their responses. We discuss that the overall good/moderate status of the streams, despite the intense agriculture in the catchments, can be due to the fact that i) a sampling strategy with repeated grab samples did not capture peak pesticide concentrations, thus underestimating acute exposure, ii) pesticide run-off indeed was low, due to measures such as buffer strips, and iii) the nutrient-rich conditions and high sediment loads counteracted pesticide toxicity. We conclude that agricultural land use was the overriding stressor in the investigated streams, including strong effects of nutrients, less apparent effects of pesticides and likely impact of hydromorphological alterations (not specifically addressed in this study).}, } @article {pmid32144559, year = {2020}, author = {Kebaili, H and Kameche, M and Innocent, C and Benayyad, A and Kosimaningrum, WE and Sahraoui, T}, title = {Scratching and transplanting of electro-active biofilm in fruit peeling leachate by ultrasound: re-inoculation in new microbial fuel cell for enhancement of bio-energy production and organic matter detection.}, journal = {Biotechnology letters}, volume = {42}, number = {6}, pages = {965-978}, doi = {10.1007/s10529-020-02858-5}, pmid = {32144559}, issn = {1573-6776}, mesh = {*Bioelectric Energy Sources ; Biofilms/*radiation effects ; Carbon/chemistry ; Electricity ; Equipment Design ; Fruit/*microbiology ; Oxidation-Reduction ; Sodium Acetate/analysis ; Sonication ; }, abstract = {OBJECTIVE: An electro-active biofilm of Fruit Peeling (FP) leachate was formed onto the Carbon Felt (CF) bio-anode in a Microbial Fuel Cell (MFC), after functioning for a long time. The electro active-biofilm thus formed was then scratched by ultrasound and re-inoculated in a new leachate to be transplanted onto the bio-anode. This procedure allowed the microbial electron charge transfer and therefore the enhancement of the bio-energy production of the fuel cell.

RESULTS: By using the repetitive mechanical biofilm removal, re-suspension and electrochemically facilitated biofilm formation, the voltage was substantially increased. In effect, the voltage of the 1st G of biofilm, rose gradually and reached its maximum value of 65 mV after 10 days. Whilst the 2nd generation allowed to obtain the maximum voltage 276 mV and without any lag time. The DCO abatement using the 1st G biofilm was 68% greater than the 3rd G 26%. Besides, the electrochemical impedance spectroscopy characterization and cyclic voltammetry of bio-anode with 2nd G biofilm confirmed the ability of electro-active biofilm formation on a new support. The biofilm transplanted showed thus greater kinetic performance, with reduced lag time demonstrating the interest of the selection that took place during the formation of successive biofilms.

CONCLUSIONS: Despite the transplantation of the electro-active biofilm onto the bio-anode, the MFC still produced relatively lower power output. Nevertheless, it has been tested successfully for monitoring and detecting the oxidation of sodium acetate substrate in the very wide concentration range 0.0025-35 g/l.}, } @article {pmid32144150, year = {2020}, author = {Anderson, EM and Sychantha, D and Brewer, D and Clarke, AJ and Geddes-McAlister, J and Khursigara, CM}, title = {Correction: Peptidoglycomics reveals compositional changes in peptidoglycan between biofilm- and planktonic-derived Pseudomonas aeruginosa.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {10}, pages = {3387}, doi = {10.1074/jbc.AAC120.012947}, pmid = {32144150}, issn = {1083-351X}, } @article {pmid32143032, year = {2020}, author = {Mielcarek, A and Rodziewicz, J and Janczukowicz, W and Struk-Sokołowska, J}, title = {The impact of biodegradable carbon sources on nutrients removal in post-denitrification biofilm reactors.}, journal = {The Science of the total environment}, volume = {720}, number = {}, pages = {137377}, doi = {10.1016/j.scitotenv.2020.137377}, pmid = {32143032}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; Nitrogen ; Nutrients ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Wastewater from households wastewater treatment plants (HWWTP) is discharged to the ground or to the surface waters. Special consideration should be given to the improvement of HWWTP effectiveness, particularly in relation to nutrients. The addition of biodegradable carbon sources to biofilm reactor, can enhance microbial activity but may also lead to filling clogging. The study aimed to compare 3 different organic substrates: acetic acid (commonly applied)and two untypical - citric acid and waste beer, under the same operational conditions in a post-denitrification biofilm reactor. The study investigated the impact of a type of organic substrate, low pH and time on: (1) biofilm growth, (2) the characteristics of extracellular polymeric substances (EPS), (3) the kinetics of nutrients removal and (4) reactor clogging. Results were referred to (5) the effectiveness of nutrients removal. The study demonstrated that low pH assured the development of a thinbiofilm. Citric acid ensured the lowest biomass volume, being by 53% lower than in the reactor with acetic acid and by as much as 61% lower than in the reactor with waste beer. The soluble EPS fraction prevailed in the total EPS in all reactors. The content of the tightly bound EPS fraction ranged from 26.93% (citric acid) to 36.32% (waste beer). Investigations showed also a high ratio of exoproteins to polysaccharide in all fractions, which indicated a significant role of proteins in developing a highly-proliferating biofilm. The treated wastewater met requirements of Polish regulations concerning COD and nitrogen concentrations.}, } @article {pmid32142554, year = {2020}, author = {Yamada, KJ and Heim, CE and Xi, X and Attri, KS and Wang, D and Zhang, W and Singh, PK and Bronich, TK and Kielian, T}, title = {Monocyte metabolic reprogramming promotes pro-inflammatory activity and Staphylococcus aureus biofilm clearance.}, journal = {PLoS pathogens}, volume = {16}, number = {3}, pages = {e1008354}, pmid = {32142554}, issn = {1553-7374}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; U01 CA198910/CA/NCI NIH HHS/United States ; P30 GM127200/GM/NIGMS NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; P30 GM110768/GM/NIGMS NIH HHS/United States ; P20 GM103427/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*drug effects ; Cellular Reprogramming/*drug effects ; Implants, Experimental/*microbiology ; Inflammation/drug therapy/metabolism/pathology ; Mice ; Monocytes/*metabolism/pathology ; Oligomycins/*pharmacology ; Oxidative Phosphorylation/drug effects ; Staphylococcal Infections/drug therapy/*metabolism/pathology ; Staphylococcus aureus/*physiology ; }, abstract = {Biofilm-associated prosthetic joint infections (PJIs) cause significant morbidity due to their recalcitrance to immune-mediated clearance and antibiotics, with Staphylococcus aureus (S. aureus) among the most prevalent pathogens. We previously demonstrated that S. aureus biofilm-associated monocytes are polarized to an anti-inflammatory phenotype and the adoptive transfer of pro-inflammatory macrophages attenuated biofilm burden, highlighting the critical role of monocyte/macrophage inflammatory status in dictating biofilm persistence. The inflammatory properties of leukocytes are linked to their metabolic state, and here we demonstrate that biofilm-associated monocytes exhibit a metabolic bias favoring oxidative phosphorylation (OxPhos) and less aerobic glycolysis to facilitate their anti-inflammatory activity and biofilm persistence. To shift monocyte metabolism in vivo and reprogram cells to a pro-inflammatory state, a nanoparticle approach was utilized to deliver the OxPhos inhibitor oligomycin to monocytes. Using a mouse model of S. aureus PJI, oligomycin nanoparticles were preferentially internalized by monocytes, which significantly reduced S. aureus biofilm burden by altering metabolism and promoting the pro-inflammatory properties of infiltrating monocytes as revealed by metabolomics and RT-qPCR, respectively. Injection of oligomycin alone had no effect on monocyte metabolism or biofilm burden, establishing that intracellular delivery of oligomycin is required to reprogram monocyte metabolic activity and that oligomycin lacks antibacterial activity against S. aureus biofilms. Remarkably, monocyte metabolic reprogramming with oligomycin nanoparticles was effective at clearing established biofilms in combination with systemic antibiotics. These findings suggest that metabolic reprogramming of biofilm-associated monocytes may represent a novel therapeutic approach for PJI.}, } @article {pmid32142402, year = {2020}, author = {Kim, D and Koo, H}, title = {Spatial Design of Polymicrobial Oral Biofilm in Its Native Disease State.}, journal = {Journal of dental research}, volume = {99}, number = {6}, pages = {597-603}, pmid = {32142402}, issn = {1544-0591}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacteria ; *Biofilms ; Candida albicans ; Child, Preschool ; Dental Caries ; Humans ; Microbiota ; Mouth ; }, abstract = {Biofilms are structured microbial communities adhered to surfaces that cause many human infections. The study of oral biofilms has revealed complex composition, spatial organization, and phenotypic/genotypic diversity of the resident microbiota at the various sites in the mouth. Yet, knowledge about the spatial arrangement, positioning, and function of the polymicrobial community across the intact biofilm architecture remains sparse. Using multiple length scale imaging and computational analysis, we discovered unique spatial designs comprising mixed interbacterial species and interkingdom communities within intact biofilms formed on teeth of toddlers with caries. Intriguing structural patterns ranging from intermixed communities with extensive coaggregation (including bacterial-fungal clustering) to spatially segregated species forming a multilayered architecture were found. Among them, a distinctive 3-dimensional structure exhibited densely clustered cariogenic pathogens that were surrounded by outer layers of mixed bacterial communities in juxtaposition, forming a highly ordered spatial organization. These findings are particularly relevant as we approach the postmicrobiome era whereby studying the spatial structure of the pathogen and commensal microbiota may be important for understanding the microbiome function at the infection site to coordinate the disease process in situ.}, } @article {pmid32140903, year = {2020}, author = {Wultańska, D and Piotrowski, M and Pituch, H}, title = {The effect of berberine chloride and/or its combination with vancomycin on the growth, biofilm formation, and motility of Clostridioides difficile.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {39}, number = {7}, pages = {1391-1399}, pmid = {32140903}, issn = {1435-4373}, mesh = {Anti-Bacterial Agents/*pharmacology ; Berberine/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Chlorides/chemistry/pharmacology ; Clostridioides difficile/classification/*drug effects/isolation & purification/physiology ; Clostridium Infections/microbiology ; Drug Synergism ; Humans ; Locomotion/*drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Vancomycin/*pharmacology ; }, abstract = {This study aims to investigate the antimicrobial and antibiofilm activity of berberine chloride (BBR) and vancomycin (VAN) as well as synergistic combinations of BBR with VAN against Clostridioides difficile strains. The effect of different concentrations of BBR on strain motility was also assessed. Twelve C. difficile strains (two reference C. difficile 630, ATCC 9689, and one control M120, and 9 clinical C. difficile strains belonging to the PCR-ribotype (RT027)) were collected and investigated for their susceptibility to BBR and VAN in planktonic and biofilm forms. Both the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of BBR for the C. difficile strains were found to vary over a broad range (256-1.024 mg/L and 256-16.384 mg/L, respectively). The MIC and MBC of VAN also varied greatly, ranging from 0.25 to 4.0 mg/L for MIC and 0.25 to 64.0 mg/L for MBC. The synergistic effect of the sub-MIC (1/2 MIC) BBR with VAN reduced of MICs of VAN against the planktonic forms of ten C. difficile strains. The sub-MIC of BBR enhanced the biofilm formation of one strain and was found to be statistically significant. In addition, the sub-MIC of BBR with VAN surprisingly enhanced the biofilm formation of one C. difficile strain. The effect of inhibition of motility in the presence of BBR was statistically significant for 3 clinical strains (p < 0.05). Altogether, BBR exhibited strong antimicrobial activity against C. difficile, and the analysis of the combination of BBR with VAN showed a synergistic effect.}, } @article {pmid32135377, year = {2020}, author = {Du, B and Gu, Y and Chen, G and Wang, G and Liu, L}, title = {Flagellar motility mediates early-stage biofilm formation in oligotrophic aquatic environment.}, journal = {Ecotoxicology and environmental safety}, volume = {194}, number = {}, pages = {110340}, doi = {10.1016/j.ecoenv.2020.110340}, pmid = {32135377}, issn = {1090-2414}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/metabolism/*physiology ; }, abstract = {Flagellar motility enables resource acquisition and noxious substance evasion, underpinning imperative ecological processes in aquatic environments. Yet the underlying mechanism that links flagellar motility with surface attachment and thereby biofilm formation, especially in conditions of limited resource availability, remains elusive. Here, we present experimental and modeling evidence to unveil bacterial motility and biofilm formation under nutrient-limited stresses with Pseudomonas aeruginosa (WT) and its nonflagellated isogenic mutant (ΔfliC) as model bacteria. Results revealed that boosted flagellar motility of WT strain promoted biofilm initialization to a peak value of 0.99 × 10[7] cells/cm[2] at 1/50 dilution after 20 min incubation. We hypothesized that bacteria can invoke instant motility acceleration for survival confronting nutrient-limited stress, accompanied by optimized chemotactic foraging through sensing ambient chemical gradients. Accordingly, accelerated cell motility in oligotrophic environment created increased cell-cell and cell-surface interactions and thereof facilitated biofilm initialization. It was confirmed by the consistence of modeling predictions and experimental results of cell velocity and surface attachment. With the development of biofilm, promotion effect of flagellar motility responding to nutrient deprivation-stress faded out. Instead, loss of motility profiting increased growth rates and extracellular protein excretion, associated with an enhancement of biofilm development for the mutant in oligotrophic aquatic environment. For both strains, nutrient limitation evidently reduced planktonic cell propagation as expected. Our results offer new insights into the mechanical understanding of biofilm formation shaped by environmental stresses and associating biological responses.}, } @article {pmid32135329, year = {2020}, author = {Gómez-Gómez, B and Sanz-Landaluce, J and Pérez-Corona, MT and Madrid, Y}, title = {Fate and effect of in-house synthesized tellurium based nanoparticles on bacterial biofilm biomass and architecture. Challenges for nanoparticles characterization in living systems.}, journal = {The Science of the total environment}, volume = {719}, number = {}, pages = {137501}, doi = {10.1016/j.scitotenv.2020.137501}, pmid = {32135329}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; Biomass ; Ecosystem ; *Nanoparticles ; Tellurium ; }, abstract = {The unexpected impact of nanoparticles on environment and human health remains as a matter of concern. In this sense, understanding the interaction between nanoparticles and biological indicators such as microorganism may help to understand their fate and effect in environmental systems. However, the adverse effect of nanoparticles greatly depends on their properties and, therefore, a precise evaluation of nanoparticles physicochemical characteristics is mandatory as the first step in accurately elucidating their behaviour in different ecosystems. Here in this work, in house-synthesized tellurium-based nanoparticles have been fully characterized for first time by means of a multi-method approach. Once characterized, the effect of these nanoparticles on Staphylococcus aureus and Escherichia coli biofilm biomass and structure was explored and quantified for first time. Moreover, the morphological transformations of tellurium based nanoparticles within the confines of a biofilm are also highlighted. Architectural metric calculations evidenced that nanoparticles were able to reduce the biovolume of the biofilm produced for both bacteria. Interestingly, the interaction between nanoparticles and bacterial communities led to the transformation of tellurium nanoparticles from sphere to rod-shaped nanoparticles. These findings open new insights into the behaviour of a type of uncommon nanoparticles such as tellurium-based nanoparticles on microbial communities.}, } @article {pmid32134563, year = {2020}, author = {Lee, YJ and Wang, C}, title = {Links between S-adenosylmethionine and Agr-based quorum sensing for biofilm development in Listeria monocytogenes EGD-e.}, journal = {MicrobiologyOpen}, volume = {9}, number = {5}, pages = {e1015}, pmid = {32134563}, issn = {2045-8827}, mesh = {Biofilms/*growth & development ; DNA, Bacterial/genetics ; Extracellular Polymeric Substance Matrix/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Listeria monocytogenes/genetics/*physiology ; Mutation ; Peptidoglycan/genetics/metabolism ; Quorum Sensing/*genetics ; S-Adenosylmethionine/*metabolism ; }, abstract = {Listeria monocytogenes is the causative agent of human listeriosis which has high hospitalization and mortality rates for individuals with weakened immune systems. The survival and dissemination of L. monocytogenes in adverse environments can be reinforced by the formation of biofilms. Therefore, this study aimed to understand the mechanisms underlying listerial biofilm development. Given that both nutrient availability and quorum sensing (QS) have been known as the factors influencing biofilm development, we hypothesized that the signal from a sentinel metabolite S-adenosylmethionine (SAM) and Agr-based QS could be synchronous in L. monocytogenes to modulate nutrient availability, the synthesis of extracellular polymeric substances (EPSs), and biofilm formation. We performed biofilm assays and quantitative real-time PCR to investigate how biofilm volumes and the expression of genes for the synthesis of EPS were affected by SAM supplementation, agr deletion, or both. We found that exogenously applied SAM induced biofilm formation and that the expression of genes encoding the EPS synthesis machineries was regulated by SAM and/or Agr QS. Moreover, the gene transcription of components acting in the methyl cycle for SAM synthesis and Agr QS was affected by the signals from the other system. In summary, we reveal an interconnection at the transcriptional level between metabolism and QS in L. monocytogenes and highlight the critical role of metabolite-oriented QS in biofilm development.}, } @article {pmid32131862, year = {2020}, author = {Bidossi, A and Bottagisio, M and De Grandi, R and De Vecchi, E}, title = {Ability of adhesion and biofilm formation of pathogens of periprosthetic joint infections on titanium-niobium nitride (TiNbN) ceramic coatings.}, journal = {Journal of orthopaedic surgery and research}, volume = {15}, number = {1}, pages = {90}, pmid = {32131862}, issn = {1749-799X}, mesh = {Alloys/*administration & dosage ; Bacterial Adhesion/*physiology ; Biocompatible Materials/*administration & dosage ; Biofilms/*growth & development ; Ceramics/therapeutic use ; Humans ; Microscopy, Confocal/methods ; Propionibacteriaceae/growth & development/isolation & purification ; Prosthesis-Related Infections/*pathology/prevention & control ; Pseudomonas aeruginosa/growth & development/isolation & purification ; Staphylococcal Infections/*pathology/prevention & control ; Staphylococcus aureus/growth & development/isolation & purification ; Staphylococcus epidermidis/growth & development/isolation & purification ; }, abstract = {BACKGROUND: Orthopedic metal implants are notoriously associated with release of metallic ions able to cause biological adverse reactions which might lead to implant loosening and failure. To limit any possible adverse reactions, ceramic coatings for orthopedic metal implants have been introduced. However, information regarding the interaction of these coatings with microbes responsible for periprosthetic joint infections (PJIs) is lacking. Hence, the aim of the present in vitro study is to assess the microbial affinity to a titanium-niobium nitride (TiNbN) coating.

METHODS: Adhesion and biofilm formation of clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Cutibacterium acnes were assessed on TiNbN-coated titanium discs in comparison with uncoated titanium and cobalt-chrome alloys discs, with either smooth or rough surfaces. Bacterial adhesion was performed by counting adhered bacteria in the first hours of incubation, and the biofilm formation was performed by means of a spectrophotometric assay and by confocal laser scan microscopy after 72 hours of incubation.

RESULTS: Overall, Staphylococcus aureus and Staphylococcus epidermidis, among the most common bacteria responsible for PJIs, displayed a significantly decreased attachment in the first hours of contact and, when cultured in presence of TiNbN coating, in comparison with CoCrMo. Biofilm formation of the four tested strains was comparable on all alloys.

CONCLUSIONS: Although the onset of a PJI is more complex than in an in vitro scenario, these findings suggest that TiNbN-coated orthopedic implants do not increase PJIs risk while ameliorating tribological and surface properties could represent a valid choice to limit possible complications such as metal hypersensitivity.}, } @article {pmid32131730, year = {2020}, author = {Nesse, LL and Osland, AM and Mo, SS and Sekse, C and Slettemeås, JS and Bruvoll, AEE and Urdahl, AM and Vestby, LK}, title = {Biofilm forming properties of quinolone resistant Escherichia coli from the broiler production chain and their dynamics in mixed biofilms.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {46}, pmid = {32131730}, issn = {1471-2180}, support = {projects 221663 and 250212//The Research Council of Norway/International ; Project 31142//Norwegian Veterinary Institute/International ; }, mesh = {Animals ; Biofilms/*growth & development ; Chickens/*microbiology ; Drug Resistance, Bacterial ; Escherichia coli/classification/isolation & purification/*physiology ; Glass ; Norway ; Phylogeny ; Quinolones/pharmacology ; Surface Properties ; }, abstract = {BACKGROUND: Quinolone resistant Escherichia coli (QREC) have been found in samples from Norwegian broiler chicken, despite quinolones not being administered to poultry in Norway. Biofilm production may be one factor contributing to the observed persistence in the broiler production chain. In the present study, 158 QREC strains from chicken caecal and retail meat samples were screened for biofilm production in microtiter plates, biofilm morphotype on Congo Red (CR) agar plates and phylotype by multiplex PCR. Furthermore, the dynamics in mixed biofilms with strains of different morphotypes were studied on glass slides and on CR agar plates.

RESULTS: All strains but one produced biofilm in microtiter plates and/or on CR agar plates at room temperature. There were no differences between strains from chicken caecum and chicken retail meat in the mean amount of biofilm produced in microtiter plates. Furthermore, no differences in biofilm production were observed between phylotypes. However, significant differences in biofilm production were found between biofilm morphotypes. The morphotype RDAR (red dry and rough, which has both curli and cellulose in the matrix, was displayed by 70% of the strains. Mean biofilm production by these strains were significantly higher than by strains with the morphotypes PDAR (pink dry and rough) with only cellulose or BDAR (brown dry and rough) with only curli. Interestingly, the two latter morphotypes produced biofilms with the morphotype RDAR when grown together. None of the strains achieved significantly higher numbers of colony forming units (cfu) in mixed biofilms than in single strain biofilms on glass slides.

CONCLUSIONS: The results indicate that QREC can form biofilm reservoirs on both inert and organic surfaces in production environments, as well as on meat. This may contribute to persistence and dissemination of the strains. Strains with both curli and cellulose in the biofilm matrix were significantly better biofilm formers than strains lacking one of these components. However, strains with only one of the components could compensate for this by producing mixed biofilms with strains having the other component, and thereby most likely enhance their probabilities of persistence in the production environment.}, } @article {pmid32131450, year = {2020}, author = {Bellich, B and Jou, IA and Caterino, M and Rizzo, R and Ravenscroft, N and Fazli, M and Tolker-Nielsen, T and Brady, JW and Cescutti, P}, title = {Burkholderia cenocepacia H111 Produces a Water-Insoluble Exopolysaccharide in Biofilm: Structural Determination and Molecular Modelling.}, journal = {International journal of molecular sciences}, volume = {21}, number = {5}, pages = {}, pmid = {32131450}, issn = {1422-0067}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; GM123283/NH/NIH HHS/United States ; }, mesh = {*Biofilms ; Burkholderia cenocepacia/*metabolism/physiology ; Glycosides/analysis ; Hydrophobic and Hydrophilic Interactions ; Polysaccharides, Bacterial/*chemistry/metabolism ; Solubility ; }, abstract = {Biofilms are a multicellular way of life, where bacterial cells are close together and embedded in a hydrated macromolecular matrix which offers a number of advantages to the cells. Extracellular polysaccharides play an important role in matrix setup and maintenance. A water-insoluble polysaccharide was isolated and purified from the biofilm produced by Burkholderia cenocepacia strain H111, a cystic fibrosis pathogen. Its composition and glycosidic linkages were determined using Gas-Liquid Chromatography-Mass Spectrometry (GLC-MS) on appropriate carbohydrate derivatives while its complete structure was unraveled by 1D and 2D NMR spectroscopy in deuterated sodium hydroxide (NaOD) aqueous solutions. All the collected data demonstrated the following repeating unit for the water-insoluble B. cenocepacia biofilm polysaccharide: [3)-α-d-Galp-(1→3)-α-d-Glcp-(1→3)-α-d-Galp-(1→3)-α-d-Manp-(1→]n Molecular modelling was used, coupled with NMR Nuclear Overhauser Effect (NOE) data, to obtain information about local structural motifs which could give hints about the polysaccharide insolubility. Both modelling and NMR data pointed at restricted dynamics of local conformations which were ascribed to the presence of inter-residue hydrogen bonds and to steric restrictions. In addition, the good correlation between NOE data and calculated interatomic distances by molecular dynamics simulations validated potential energy functions used for calculations.}, } @article {pmid32128090, year = {2019}, author = {Mir, Z and Nodeh Farahani, N and Abbasian, S and Alinejad, F and Sattarzadeh, M and Pouriran, R and Dahmardehei, M and Mirzaii, M and Khoramrooz, SS and Darban-Sarokhalil, D}, title = {The prevalence of exotoxins, adhesion, and biofilm-related genes in Staphylococcus aureus isolates from the main burn center of Tehran, Iran.}, journal = {Iranian journal of basic medical sciences}, volume = {22}, number = {11}, pages = {1267-1274}, pmid = {32128090}, issn = {2008-3866}, abstract = {OBJECTIVES: The present study investigated the prevalence of genes encoding for exotoxins, adhesion and biofilm factors in Staphylococcus aureus isolates obtained from samples in a referral burn hospital in Tehran, Iran.

MATERIALS AND METHODS: S. aureus isolates obtained from patients, personnel and surfaces in the wards of a burn hospital were identified and confirmed by biochemical and molecular tests, respectively. The susceptibility of isolates was determined using the disk diffusion method. Virulence factors were detected by multiplex PCR.

RESULTS: The frequency of hla, hlb, hld, hlg, tst and pvl genes was 92.8%, 34.7%, 89.8%, 11.9%, 10.7%, and 0.5% respectively. The results revealed that the hla gene had the highest frequency among isolates (94.4% for methicillin-resistant S. aureus (MRSA) and 89.8% for methicillin-susceptible S. aureus (MSSA)). The most prevalent adhesion and biofilm-related gene was eno (85.6%). The prevalence of the remaining genes was as follows: fib (71.8%), clfB (70%), cna (59.2 %), fnbB (17.9%), icaA (72.4%), and icaD (85.6%). The incidence of fib, hlb, hlg, and tst genes was significantly higher in MRSA isolates compare to the MSSA isolates. Moreover, the resistance rates for all antibiotics were higher is MRSA isolates except for nitrofurantoin and chloramphenicol antibiotics.

CONCLUSION: Data indicate the high prevalence rates of virulence factors among S. aureus isolates, especially MRSA strains in the burn hospital. This should to be taken into account in the development of an effective infection control policy and continuous monitoring of drug resistance in hospitals.}, } @article {pmid32126585, year = {2020}, author = {Hubbard, ATM and Newire, E and Botelho, J and Reiné, J and Wright, E and Murphy, EA and Hutton, W and Roberts, AP}, title = {Isolation of an antimicrobial-resistant, biofilm-forming, Klebsiella grimontii isolate from a reusable water bottle.}, journal = {MicrobiologyOpen}, volume = {9}, number = {6}, pages = {1128-1134}, pmid = {32126585}, issn = {2045-8827}, mesh = {Amoxicillin/pharmacology ; Ampicillin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Drinking Water/*microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Fosfomycin/pharmacology ; Genome, Bacterial/genetics ; Humans ; Klebsiella/classification/*genetics/*isolation & purification ; Microbial Sensitivity Tests ; Polypropylenes ; Polystyrenes ; Virulence Factors/genetics ; Water Microbiology ; Whole Genome Sequencing ; beta-Lactamases/genetics ; }, abstract = {A reusable water bottle was swabbed as part of the citizen science project "Swab and Send," and a Klebsiella grimontii isolate was recovered on chromogenic agar and designated SS141. Whole-genome sequencing of SS141 showed it has the potential to be a human pathogen as it contains the biosynthetic gene cluster for the potent cytotoxin, kleboxymycin, and genes for other virulence factors. The genome also contains the antibiotic-resistant genes, blaOXY-6-4 , and a variant of fosA, which is likely to explain the observed resistance to ampicillin, amoxicillin, and fosfomycin. We have also shown that SS141 forms biofilms on both polystyrene and polypropylene surfaces, providing a reasonable explanation for its ability to colonize a reusable water bottle. With the increasing use of reusable water bottles as an alternative to disposables and a strong forecast for growth in this industry over the next decade, this study highlights the need for cleanliness comparable to other reusable culinary items.}, } @article {pmid32126482, year = {2020}, author = {Wang, R and Wang, X and Deng, C and Chen, Z and Chen, Y and Feng, X and Zhong, Z}, title = {Partial nitritation performance and microbial community in sequencing batch biofilm reactor filled with zeolite under organics oppression and its recovery strategy.}, journal = {Bioresource technology}, volume = {305}, number = {}, pages = {123031}, doi = {10.1016/j.biortech.2020.123031}, pmid = {32126482}, issn = {1873-2976}, abstract = {Influences of organics on partial nitritation performance were investigated in a lab-scale sequencing batch biofilm reactor filled with zeolite. Significant differences in nitrite production rate (NPR) were observed between different dosages of glucose. With influent COD/N ratio from 0 to 1.5, NPR declined from 0.4 to 0.05 kg/(m[3]·d). Meanwhile, an appropriate NO2[-]-N/NH4[+]-N ratio (1.4 ± 0.5) could be obtained for simultaneous anammox denitrification at COD/N ratio of 0.5. Increasing airflow rate was found as an effective recovery strategy. Other than competition of heterotrophs with nitrifiers for dissolved oxygen, it has been verified that addition of organics generated higher free ammonia, and then further inhibitedammonium oxidizing bacteria (AOB). Moreover, three-dimensional excitation-emission matrix (3D-EEM) results revealed that protein-like and humic acid-like substances were the main components in extracellularpolymericsubstances (EPS). And high-throughput sequencing analysis demonstrated that the relative abundance of AOB decreased.}, } @article {pmid32126307, year = {2020}, author = {Garcez, AS and Barros, LC and Fernandes, MRU and Fujii, DN and Suzuki, SS and Nepomuceno, R}, title = {Fluorescence image and microbiological analysis of biofilm retained around healthy and inflamed orthodontic miniscrews.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {30}, number = {}, pages = {101707}, doi = {10.1016/j.pdpdt.2020.101707}, pmid = {32126307}, issn = {1873-1597}, mesh = {Biofilms ; Bone Screws ; Fluorescence ; Humans ; *Orthodontic Anchorage Procedures ; *Photochemotherapy/methods ; Photosensitizing Agents ; Republic of Korea ; }, abstract = {INTRODUCTION: Peri-miniscrew inflammation is one of the causes of orthodontic miniscrew failure.

OBJECTIVE: The aim of this study was to correlate and quantify throughout autofluorescence images, PCR and microbiologic count of biofilm retained around orthodontic miniscrew and the presence of Porphyromonas gingivalis.

MATERIALS AND METHODS: Forty miniscrews used for orthodontic treatment were evaluated during orthodontic treatment, collected from patients and divided into two groups: healthy and inflamed miniscrews. To be considered inflamed, the samples should present: loss of stability checked by periotest®, clinical presence of mucositis, red aspect of the gum or bleeding around the miniscrew. Immediately after removal of the miniscrews, they were photographed using a macro 100 lens and a Pentax camera coupled to a fluorescent equipment - Qscan (AioBio - Korea) with 405 nm excitation wavelength and a blue band filter. A microbiologic sample was collected with a sterile microbrush scrubbed around the miniscrew tread. Fluorescent images were analyzed with ImageJ software to quantify fluorescent intensity and fluorescent area and microbiological samples were submitted to CFU count for total contamination and q-PCR assay to quantify Porphyromonas gingivalis.

RESULTS: The results showed a good correlation between CFU count and fluorescent intensity and PCR/fluorescent area. The healthy miniscrews presented less fluorescent intensity and lower CFU count when compared to inflamed miniscrews. q-PCR analysis showed a higher number of P. gingivalis contamination around inflamed miniscrews.

CONCLUSION: Quantification of biofilm retained by miniscrew by images of autofluorescence is a simple and reliable method with great potential for clinical use to monitory inflammation around miniscrew and risk of loss.}, } @article {pmid32125643, year = {2020}, author = {Łusiak-Szelachowska, M and Weber-Dąbrowska, B and Górski, A}, title = {Bacteriophages and Lysins in Biofilm Control.}, journal = {Virologica Sinica}, volume = {35}, number = {2}, pages = {125-133}, pmid = {32125643}, issn = {1995-820X}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacteriophages/*chemistry ; Biofilms/*drug effects ; Communicable Diseases/*therapy ; Drug Therapy, Combination ; Humans ; *Phage Therapy ; Viral Proteins/*therapeutic use ; }, abstract = {To formulate the optimal strategy of combatting bacterial biofilms, in this review we update current knowledge on the growing problem of biofilm formation and its resistance to antibiotics which has spurred the search for new strategies to deal with this complication. Based on recent findings, the role of bacteriophages in the prevention and elimination of biofilm-related infections has been emphasized. In vitro, ex vivo and in vivo biofilm treatment models with single bacteriophages or phage cocktails have been compared. A combined use of bacteriophages with antibiotics in vitro or in vivo confirms earlier reports of the synergistic effect of these agents in improving biofilm removal. Furthermore, studies on the application of phage-derived lysins in vitro, ex vivo or in vivo against biofilm-related infections are encouraging. The strategy of combined use of phage and antibiotics seems to be different from using lysins and antibiotics. These findings suggest that phages and lysins alone or in combination with antibiotics may be an efficient weapon against biofilm formation in vivo and ex vivo, which could be useful in formulating novel strategies to combat bacterial infections. Those findings proved to be relevant in the prevention and destruction of biofilms occurring during urinary tract infections, orthopedic implant-related infections, periodontal and peri-implant infections. In conclusion, it appears that most efficient strategy of eliminating biofilms involves phages or lysins in combination with antibiotics, but the optimal scheme of their administration requires further studies.}, } @article {pmid32125530, year = {2020}, author = {Martínez-Hernández, M and Reda, B and Hannig, M}, title = {Chlorhexidine rinsing inhibits biofilm formation and causes biofilm disruption on dental enamel in situ.}, journal = {Clinical oral investigations}, volume = {24}, number = {11}, pages = {3843-3853}, pmid = {32125530}, issn = {1436-3771}, support = {SFB 1027//German Research Foundation/ ; }, mesh = {Animals ; *Anti-Infective Agents, Local/pharmacology ; Biofilms ; Cattle ; *Chlorhexidine/pharmacology ; Dental Enamel ; Humans ; Microscopy, Fluorescence ; Mouthwashes/pharmacology ; }, abstract = {OBJECTIVES: This in situ study aims to evaluate the effects of chlorhexidine (CHX) mouth rinsing on biofilm formation and moreover on the disruption of existing mature dental biofilms.

METHODS: Biofilms were formed in situ by five volunteers on bovine enamel specimens fixed to individual acrylic splints. For biofilm formation analysis, the volunteers intraorally exposed the splint for 48 h. Mouth rinsing using 10 ml of 0.2% CHX or water as control was performed for 30 s every 12 h. For analysis of biofilm disruption, the biofilm was formed on enamel specimens for 48 h. Then, the first CHX rinse was carried out. A second rinse followed after an additional 12 h, again for 30 s using 10 ml of 0.2% CHX. Biofilm vitality was imaged by fluorescence microscopy after vital fluorescence staining. Additionally, the ultrastructure of the biofilm was examined by transmission electron microscopy.

RESULTS: Rinses with 0.2% CHX significantly reduced biofilm formation on enamel. Both biofilm colonization and vitality were dramatically impaired. Moreover, a considerable biofilm disruption induced by the CHX rinses was observed. Remarkably, a single application of CHX to a 48-h mature biofilm causes biofilm ultrastructure alterations and induces a substantial reduction in biofilm thickness and bacterial vitality.

CONCLUSIONS: CHX mouth rinses induced a significant inhibition of biofilm formation on native enamel. Furthermore, an important biofilm disrupting effect under in situ conditions was detected.

CLINICAL RELEVANCE: CHX rinses could be used as a short-term treatment protocol for biofilm management focused on patients unable to reach adequate oral hygiene.}, } @article {pmid32123776, year = {2020}, author = {Garcia, IM and Rodrigues, SB and Rodrigues Gama, ME and Branco Leitune, VC and Melo, MA and Collares, FM}, title = {Guanidine derivative inhibits C. albicans biofilm growth on denture liner without promote loss of materials' resistance.}, journal = {Bioactive materials}, volume = {5}, number = {2}, pages = {228-232}, pmid = {32123776}, issn = {2452-199X}, abstract = {To reduce the burden of denture stomatitis and oral candidiasis, an aqueous solution containing polyhexamethylene guanidine hydrochloride (PHMGH) was investigated as an antifungal disinfectant against the leading cause of these oral conditions, Candida albicans. The solutions formulated with concentrations ranging from 0.125 to 0.50 wt% enabled increasing disinfection at the initial 5min-contact with 72h-mature candida biofilms formed on denture liner specimens. After 10 min-contact, the solution at lower concentration has reached total fungal elimination. The results also indicated that the denture liners preserved their mechanical property after the maximum contact time with the solution at the highest tested concentration. The PHMGH aqueous solutions at 0.125 wt% could be applied to promote interim denture liner disinfection without promoting the loss of materials' mechanical property.}, } @article {pmid32123422, year = {2020}, author = {Silva, HRA and de Souza, GM and Fernandes, JD and Constantino, CJL and Winkelstroter, LK}, title = {Unravelling the effects of the food components ascorbic acid and capsaicin as a novel anti-biofilm agent against Escherichia coli.}, journal = {Journal of food science and technology}, volume = {57}, number = {3}, pages = {1013-1020}, pmid = {32123422}, issn = {0022-1155}, abstract = {This study aimed to evaluate the influence of capsaicin and ascorbic acid on the physiology of biofilm formation and dispersion. The influence of the E. coli ATCC 25922 biofilm and five E. coli isolates were observed in the presence of sodium hypochlorite 2.5 mM and subinhibitory concentrations of capsaicin (7 mM) and ascorbic acid (100 mM). The cells counts were performed through standard plaque count and the architecture visualized by confocal microscopy. The proteins, carbohydrates, and DNA present in the biofilm matrix were also quantified. There was a reduction in adhered cells in the presence of capsaicin (7 mM) and ascorbic acid (100 mM) in the biofilm formation kinetics, however, regarding the dispersion, only capsaicin altered the biofilm, data confirmed by confocal fluorescence microscopy (p < 0.05). It was noted that the matrix composition is dynamic and may be affected by changes in growth conditions such as the presence of antimicrobial substances.}, } @article {pmid32122829, year = {2020}, author = {Abbasi, MA and Zeb, A and Rehman, A and Siddiqui, SZ and Shah, SAA and Shahid, M and Fatima, H}, title = {Synthesis, Bacterial biofilm inhibition and cytotoxicity of new N-Alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {33}, number = {1}, pages = {41-47}, pmid = {32122829}, issn = {1011-601X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacillus subtilis/drug effects ; Biofilms/*drug effects ; Cattle ; Escherichia coli/drug effects ; Hemolysis/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; Sulfonamides/*chemical synthesis/chemistry/*pharmacology/*toxicity ; }, abstract = {The current research was commenced by reaction of 1,4-benzodioxane-6-amine (1) with 4-nitrobenzenesulfonyl chloride (2) in the presence of aqueous base under dynamic pH control at 9 to yield N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamide (3) which was further reacted with a series of alkyl/aralkyl halides (4a-i) in polar aprotic solvent using catalytic amount of lithium hydride which acts as base to afford some new N-alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides (5a-i). The projected structures of all the synthesized derivatives were characterized by contemporary techniques i.e., IR, 1H-NMR and EIMS. The biofilm Inhibitory action of all synthesized molecules was carried out against Escherichia coli and Bacillus subtilis. It was inferred from their results that 5f and 5e exhibited suitable inhibitory action against the biofilms of these bacterial strains. Moreover, their cytotoxicity was also checked and it was concluded that these synthesized molecules displayed docile cytotoxicity.}, } @article {pmid32122607, year = {2020}, author = {Alwis, PA and Treerat, P and Gong, L and Deveson Lucas, D and Allwood, EM and Prescott, M and Devenish, RJ and Adler, B and Boyce, JD}, title = {Disruption of the Burkholderia pseudomallei two-component signal transduction system BbeR-BbeS leads to increased extracellular DNA secretion and altered biofilm formation.}, journal = {Veterinary microbiology}, volume = {242}, number = {}, pages = {108603}, doi = {10.1016/j.vetmic.2020.108603}, pmid = {32122607}, issn = {1873-2542}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Burkholderia pseudomallei/*genetics/*physiology ; DNA/*metabolism ; *Gene Deletion ; Melioidosis/microbiology ; Mice, Inbred BALB C ; Mutation ; Phenotype ; Signal Transduction/*genetics ; Virulence ; }, abstract = {Two-component signal transduction systems (TCSTS) are abundant among prokaryotes and regulate important functions, including drug resistance and virulence. The Gram-negative bacterium Burkholderia pseudomallei, which causes the severe infectious disease melioidosis, encodes 136 putative TCSTS components. In silico analyses of these TCSTS indicated that the predicted BbeR-BbeS system (BPSL1036-BPSL1037) displayed significant amino acid sequence similarity to the Shigella flexneri virulence-associated OmpR-EnvZ osmoregulator. To assess the function of the B. pseudomallei BbeR-BbeS system, we constructed by allelic exchange a ΔbbeRS double mutant strain lacking both genes, and single ΔbbeR and ΔbbeS mutants. All three mutant strains caused disease in the BALB/c acute melioidosis model at the same rate as the wild-type strain, displayed unchanged swarming motility on semi-solid medium, and were unaffected for viability on high-osmolarity media. However, when cultured at 37 °C for at least 14 days, ΔbbeS and ΔbbeR colonies developed a distinct, hypermucoid morphology absent in similarly-cultured wild-type colonies. At both 30 °C and 37 °C, these hypermucoid strains produced wild-type levels of type I capsule but released increased quantities of extracellular DNA (eDNA). Upon static growth in liquid medium, all B. pseudomallei strains produced pellicle biofilms that contained DNA in close association with bacterial cells; however, the ΔbbeS and ΔbbeR strains produced increased biofilms with altered microscopic architecture compared to the wild-type. Unusually, while the ΔbbeS and ΔbbeR single-deletion mutants displayed clear phenotypes, the ΔbbeRS double-deletion mutant was indistinguishable from the wild-type strain. We propose that BbeR-BbeS indirectly affects eDNA secretion and biofilm formation through cross-talk with one or more other TCSTS.}, } @article {pmid32121646, year = {2020}, author = {Santana, JCC and Gardim, RB and Almeida, PF and Borini, GB and Quispe, APB and Llanos, SAV and Heredia, JA and Zamuner, S and Gamarra, FMC and Farias, TMB and Ho, LL and Berssaneti, FT}, title = {Valorization of Chicken Feet By-Product of the Poultry Industry: High Qualities of Gelatin and Biofilm from Extraction of Collagen.}, journal = {Polymers}, volume = {12}, number = {3}, pages = {}, pmid = {32121646}, issn = {2073-4360}, support = {CNPq-Capes-FAPIC/CNPq (UNINOVE)//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {In this research, products with high quality were obtained from natural sources. The sensorial qualities, chemical characterization, and physical properties of gelatin extracted from chicken feet were compared with commercial gelatins. The extraction process was performed using acetic acid on a concentration ranging from 0.318% to 3.682%, processing time between 1.0 h and 8.4 h and extraction temperature between 43.3 °C and 76.8 °C. After the end of each assay, the yield was measured. Results showed that, under the best conditions, the collagen extraction yield was above 8%, and comprised 78.525 g/100 g of protein. Collagen analyzed by ICP-MS was composed of 99.44% of macro-minerals that are of great importance to human health. ATR-FTIR analysis showed that approximately 70.90% of the total protein from chicken feet is collagen, whereas, in commercial gelatin, only 30.31% is collagen. When comparing chicken gelatin with commercial gelatin, most sensory attributes were similar and chicken gelatin gained acceptance by more than 80% of the consumers. Additionally, the collagen films obtained from chicken feet and swine showed water absorption, odors, and texture characteristics similar to commercial material, such as latex and celofane. Consequently, due to its similarity to human skin, it is possible to apply it as a biocurative.}, } @article {pmid32121332, year = {2020}, author = {Reigada, I and Pérez-Tanoira, R and Patel, JZ and Savijoki, K and Yli-Kauhaluoma, J and Kinnari, TJ and Fallarero, A}, title = {Strategies to Prevent Biofilm Infections on Biomaterials: Effect of Novel Naturally-Derived Biofilm Inhibitors on a Competitive Colonization Model of Titanium by Staphylococcus aureus and SaOS-2 Cells.}, journal = {Microorganisms}, volume = {8}, number = {3}, pages = {}, pmid = {32121332}, issn = {2076-2607}, support = {722467//H2020 Marie Skłodowska-Curie Actions/ ; N/A//Jane ja Aatos Erkon Säätiö/ ; }, abstract = {Biofilm-mediated infection is a major cause of bone prosthesis failure. The lack of molecules able to act in biofilms has driven research aimed at identifying new anti-biofilm agents via chemical screens. However, to be able to accommodate a large number of compounds, the testing conditions of these screenings end up being typically far from the clinical scenario. In this study, we assess the potential applicability of three previously discovered anti-biofilm compounds to be part of implanted medical devices by testing them on in vitro systems that more closely resemble the clinical scenario. To that end, we used a competition model based on the co-culture of SaOS-2 mammalian cells and Staphylococcus aureus (collection and clinical strains) on a titanium surface, as well as titanium pre-conditioned with high serum protein concentration. Additionally, we studied whether these compounds enhance the previously proven protective effect of pre-incubating titanium with SaOS-2 cells. Out of the three, DHA1 was the one with the highest potential, showing a preventive effect on bacterial adherence in all tested conditions, making it the most promising agent for incorporation into bone implants. This study emphasizes and demonstrates the importance of using meaningful experimental models, where potential antimicrobials ought to be tested for the protection of biomaterials in translational applications.}, } @article {pmid32120451, year = {2020}, author = {Zhu, Y and Li, JJ and Reng, J and Wang, S and Zhang, R and Wang, B}, title = {Global trends of Pseudomonas aeruginosa biofilm research in the past two decades: A bibliometric study.}, journal = {MicrobiologyOpen}, volume = {9}, number = {6}, pages = {1102-1112}, pmid = {32120451}, issn = {2045-8827}, mesh = {*Bibliometrics ; Biofilms/*growth & development ; Humans ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*growth & development ; Software ; Soil Microbiology ; Water Microbiology ; }, abstract = {Pseudomonas aeruginosa biofilm formation is a primary cause of chronic infections. This has been a highly active area of research over the past two decades due to causing high mortality risks in immunocompromised patients. This study evaluates global trends in the dynamic and rapidly evolving field of P. aeruginosa biofilm research through bibliometric and visualized analyses. Publications from 1994 to 2018 on P. aeruginosa biofilm research were retrieved from Web of Science, Scopus, and PubMed, and their bibliometric data were systematically studied. The VOSviewer software was used to conduct global analyses of bibliographic coupling, coauthorship, cocitation, and co-occurrence. A total of 9,527 publications were included in this study. The overall number of publications and research interest in the field displayed a strongly rising trend. The USA made the greatest contributions to the field, with the highest h-index and number of citations compared with other countries, while Denmark had the highest average citation per publication. The Journal of Bacteriology had the highest number of publications in the field, while the University of Copenhagen was the institution with the highest contribution influence. Co-occurrence network maps revealed that the most prominent topics in P. aeruginosa biofilm research were mechanistic studies, in vitro/in vivo studies, and biofilm formation studies. Pseudomonas aeruginosa biofilms constitute a dynamic research area in microbiology with increasing global research interest. Future studies will likely focus on investigating the mechanisms of biofilm formation to solve infection-associated clinical problems.}, } @article {pmid32120041, year = {2020}, author = {Stewart, PS and Bjarnsholt, T}, title = {Risk factors for chronic biofilm-related infection associated with implanted medical devices.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {26}, number = {8}, pages = {1034-1038}, doi = {10.1016/j.cmi.2020.02.027}, pmid = {32120041}, issn = {1469-0691}, mesh = {Animals ; Biofilms/*growth & development ; Breast Implants/microbiology ; Female ; Foreign-Body Reaction/*etiology ; Humans ; Joint Prosthesis/microbiology ; Male ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*etiology ; Risk Factors ; Surgical Mesh/microbiology ; }, abstract = {BACKGROUND: The use of implanted medical devices is associated with a small but clinically important risk of foreign body infection. A key question is: why do some patients develop chronic infection associated with an implanted device, but most do not?

AIMS: The literature on patient-specific risk factors for chronic infections associated with five types of implants was surveyed to glean clues about the etiology of these infections.

SOURCES: Data were collected from 47 articles through calendar year 2017 for five categories of device-related infections: cardiovascular implantable electronic devices (CIEDs), hernia meshes, prosthetic hip and knee joints, prosthetic shoulder joints and breast implants.

CONTENT: Important risk factors include immunomodulation/steroid therapy, diabetes, smoking, and renal disease/haemodialysis-findings that point to a critical role of a compromised innate immune response in determining vulnerable subpopulations.

IMPLICATIONS: A model of biofilm-related device infection is presented that posits defects in the innate immune response both systemically and locally, in the immediate vicinity of an abiotic biomaterial. The limitations of in vitro and animal models of chronic device-related infections are discussed in this context as are implications for research and clinical practice.}, } @article {pmid32119949, year = {2020}, author = {Elshaarawy, RFM and Ismail, LA and Alfaifi, MY and Rizk, MA and Eltamany, EE and Janiak, C}, title = {Inhibitory activity of biofunctionalized silver-capped N-methylated water-soluble chitosan thiomer for microbial and biofilm infections.}, journal = {International journal of biological macromolecules}, volume = {152}, number = {}, pages = {709-717}, doi = {10.1016/j.ijbiomac.2020.02.284}, pmid = {32119949}, issn = {1879-0003}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Chitosan/*chemistry ; Escherichia coli/drug effects ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests/methods ; Nanocomposites/chemistry ; Silver/*chemistry ; Water/*chemistry ; }, abstract = {One of the most important self-defense strategies employed by bacteria to resist the action of antibiotics is a biofilm formation upon the infected surface. Thus, there is an urgent need to explore novel candidates that have potent antibacterial and anti-biofilm effects to tackle this challenge. In this endeavor, we have transformed shrimp shell wastes to N-methylated water-soluble chitosan thiomer (MWSCT) which was used as either a chelating agent or bio-reductant and capping agent for Ag(I) ions in the preparation of a Ag(I)MWSCT complex or silver nanocomposite (Ag(0)MWSCT), for targeting antibacterial and anti-biofilm applications. The antibacterial and anti-biofilm performance of the new methylated chitosan thiomer (MWSCT) and its silver architectures (Ag(I)MWSCT, Ag(0)MWSCT) were assessed in vitro against E. coli and S. aureus. These new materials have significant capacities to synergistically inhibit the proliferation of the targeted bacterial cells and biofilm formation, in a structure- and species-dependent manner. Ag(0)MWSCT emerged as the most potent compound in inhibiting the growth of bacterial strains (MICE. coli/ MICS. aureus = 0.05/ 0.34 μg/mL, 1.6-/ 2.5-times lower than that recorded for the clinical drug (ciprofloxacin, Cipro). Also, this nanocomposite showed the highest anti-biofilm effects (only 1.7% E. coli biofilm growth; 11.8% staphylococcal biofilm growth).}, } @article {pmid32118481, year = {2019}, author = {Svobodová, L and Lederer, T and Rosická, P and Svoboda, P and Novák, L and Dostálková, J and Jirků, V}, title = {Advanced characterization of natural biofilm on nanofiber scaffold.}, journal = {Physiological research}, volume = {68}, number = {Suppl 4}, pages = {S491-S499}, doi = {10.33549/physiolres.934384}, pmid = {32118481}, issn = {1802-9973}, mesh = {*Biofilms ; *Culture Media ; *Nanofibers ; Polyurethanes ; Porosity ; Rhodococcus ; }, abstract = {Nanofiber scaffolds provide numerous advantages over common carriers engineered for microorganisms. The most important advantage is an increased speed of primary surface colonization (up to four times faster), which shortens the time required for the areal biofilm formation and optimum performance of attached microorganisms (higher efficiency of biological activity of up to twice as fast). Image analysis predicts early formation of biofilm even in beginning stages; analysis of biofilm reveals the different structures of bacterial colonies on both scaffolds (higher porosity, size, and number of bacterial colonies on nanofiber's surface). The image analysis correlates well with determinations of dry matter (linear correlation of 0.96) and proteins (linear correlation of 0.89).}, } @article {pmid32118127, year = {2020}, author = {Ghosh, A and Jayaraman, N and Chatterji, D}, title = {Small-Molecule Inhibition of Bacterial Biofilm.}, journal = {ACS omega}, volume = {5}, number = {7}, pages = {3108-3115}, pmid = {32118127}, issn = {2470-1343}, abstract = {Antibiotic resistance is a massive and serious threat to human welfare and healthcare. Apart from being genetically resistant to antibiotics, the other important mechanism by which bacteria can evade antibiotics is multidrug tolerance. Here cells enter into a transiently nongrowing phase, and as a result, latent infection remains inside the host, causing disease recurrence. Biofilm-derived antibiotic tolerance and persister formation of the pathogenic bacteria inside the host remain a serious issue of treatment failure and recurrent chronic infection in the case of all major pathogens. As a result, new chemotherapeutic agents are sought that specifically inhibit biofilm formation or maturation as well as cause the dispersion of mature biofilms, thus allowing the conventional drugs to kill sensitive cells residing inside. This mini-review attempts to analyze different small-molecule-based chemical approaches that have been used to enable bacterial biofilm inhibition at different steps of maturation.}, } @article {pmid32117880, year = {2020}, author = {Vogel, J and Wakker-Havinga, M and Setroikromo, R and Quax, WJ}, title = {Immobilized Acylase PvdQ Reduces Pseudomonas aeruginosa Biofilm Formation on PDMS Silicone.}, journal = {Frontiers in chemistry}, volume = {8}, number = {}, pages = {54}, pmid = {32117880}, issn = {2296-2646}, abstract = {The bacterial biofilm plays a key role in nosocomial infections, especially those related to medical devices in sustained contact with patients. The active dispersion of bacterial cells out of biofilms acts as a reservoir for infectious diseases. The formation of such biofilms is a highly complex process, which is coordinated by many regulatory mechanisms of the pathogen including quorum sensing (QS). Many bacteria coordinate the expression of key virulence factors dependent on their population density through QS. The inhibition of this system is called quorum quenching (QQ). Thus, preventing the development of biofilms is considered a promising approach to prevent the development of hard to treat infections. Enzymatic QQ is the concept of interfering with the QS system of bacteria outside the cell. PvdQ is an acylase with an N-terminal nucleophile (Ntn-hydrolase) that is a part of the pyoverdine gene cluster (pvd). It is able to cleave irreversibly the amide bond of long chain N-acyl homoserine lactones (AHL) rendering them inactive. Long chain AHLs are the main signaling molecule in the QS system of the gram-negative pathogen Pseudomonas aeruginosa PA01, which is known for surface-associated biofilms on indwelling catheters and is also the cause of catheter-associated urinary tract infections. Furthermore, PA01 is a well characterized pathogen with respect to QS as well as QQ. In this study, we immobilized the acylase PvdQ on polydimethylsiloxane silicone (PDMS), creating a surface with quorum quenching properties. The goal is to control infections by minimizing the colonization of indwelling medical devices such as urinary catheters or intravascular catheters. The enzyme activity was confirmed by testing the degradation of the main auto-inducer that mediates QS in P. aeruginosa. In this article we report for the first time a successful immobilization of the quorum quenching acylase PvdQ on PDMS silicone. We could show that immobilized PvdQ retained its activity after the coating procedure and showed a 6-fold reduction of the auto-inducer 3-oxo-C12 in a biosensor setup. Further we report significant reduction of a P. aeruginosa PA01 biofilm on a coated PDMS surface compared to the same untreated material.}, } @article {pmid32117803, year = {2020}, author = {Santos, R and Cavalheiro, M and Costa, C and Takahashi-Nakaguchi, A and Okamoto, M and Chibana, H and Teixeira, MC}, title = {Screening the Drug:H[+] Antiporter Family for a Role in Biofilm Formation in Candida glabrata.}, journal = {Frontiers in cellular and infection microbiology}, volume = {10}, number = {}, pages = {29}, pmid = {32117803}, issn = {2235-2988}, mesh = {Antifungal Agents ; Antiporters/genetics ; Biofilms ; *Candida glabrata/genetics ; Humans ; Microbial Sensitivity Tests ; *Pharmaceutical Preparations ; }, abstract = {Biofilm formation and drug resistance are two key pathogenesis traits exhibited by Candida glabrata as a human pathogen. Interestingly, specific pathways appear to be in the crossroad between the two phenomena, making them promising targets for drug development. In this study, the 10 multidrug resistance transporters of the Drug:H[+] Antiporter family of C. glabrata were screened for a role in biofilm formation. Besides previously identified players in this process, namely CgTpo1_2 and CgQdr2, two others are shown to contribute to biofilm formation: CgDtr1 and CgTpo4. The deletion of each of these genes was found to lead to lower biofilm formation, in both SDB and RPMI media, while their expression was found to increase during biofilm development and to be controlled by the transcription factor CgTec1, a predicted key regulator of biofilm formation. Additionally, the deletion of CgDTR1, CgTPO4, or even CgQDR2 was found to increase plasma membrane potential and lead to decreased expression of adhesin encoding genes, particularly CgALS1 and CgEPA1, during biofilm formation. Although the exact role of these drug transporters in biofilm formation remains elusive, our current model suggests that their control over membrane potential by the transport of charged molecules, may affect the perception of nutrient availability, which in turn may delay the triggering of adhesion and biofilm formation.}, } @article {pmid32117679, year = {2020}, author = {Vyas, R and Pandya, M and Pohnerkar, J and Kumar, GN}, title = {Vitreoscilla hemoglobin promotes biofilm expansion and mitigates sporulation in Bacillus subtilis DK1042.}, journal = {3 Biotech}, volume = {10}, number = {3}, pages = {118}, pmid = {32117679}, issn = {2190-572X}, abstract = {Biofilm formation is considered as a stress combating strategy adopted by bacteria in response to variety of cellular and environmental signals. Impaired respiration due to low oxygen concentrations is one such signal that triggers wrinkling and robust biofilm formation in Bacillus subtilis. Vitreoscilla hemoglobin (VHb) improves microaerobic growth and bioproduct synthesis in a variety of bacteria by supplying oxygen to the respiratory chain. Present study was carried out to determine the effect of VHb on multicellularity of B. subtilis. Thus, B. subtilis DK1042 (WT) was genetically modified to express vgb and gfp genes under the control of P43 promoter at amyE locus by double cross over events. Biofilm formation by the integrant NRM1113 and WT was monitored on Lysogeny broth (LB) and LB containing glycerol and manganese (LBGM) medium. The WT produced more wrinkled colonies than NRM1113 on LB and LBGM medium. Concomitantly, biofilm-associated sporulation and production of pulcherriminic acid was decreased in NRM1113 as compared to WT on LB as well as LBGM. Expression studies of genes encoding structural components of biofilms revealed ~ 70% down-regulation of bslA gene in NRM1113 on both LB and LBGM which is correlated with reduced wrinkling in NRM1113. Moreover, NRM1113 showed increased colony expansion compared to WT in LB, LBGM and high osmolarity conditions. VHb expression alters various processes in different host cells, our study represents that VHb modulates biofilm formation, sporulation and pulcherriminic acid formation in B. subtilis DK1042.}, } @article {pmid32117185, year = {2020}, author = {Zheng, J and Chen, Z and Lin, Z and Sun, X and Bai, B and Xu, G and Chen, J and Yu, Z and Qu, D}, title = {Radezolid Is More Effective Than Linezolid Against Planktonic Cells and Inhibits Enterococcus faecalis Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {196}, pmid = {32117185}, issn = {1664-302X}, abstract = {The aim of this study was to compare the effects of radezolid and linezolid on planktonic and biofilm cells of Enterococcus faecalis. A total of 302 E. faecalis clinical isolates were collected, and the minimum inhibitory concentrations (MICs) of radezolid and linezolid were determined by the agar dilution method. Changes in the transcriptome of a high-level, in vitro-induced linezolid-resistant isolate were assessed by RNA sequencing and RT-qPCR, and the roles of efflux pump-related genes were confirmed by overexpression analysis. Biofilm biomass was evaluated by crystal violet staining and the adherent cells in the biofilms were quantified according to CFU numbers. The MIC50/MIC90 values of radezolid (0.25/0.50 mg/L) against the 302 E. faecalis clinical isolates were eightfold lower than those of linezolid (2/4 mg/L). The radezolid MICs against the high-level linezolid-resistant isolates (linezolid MICs ≥ 64 mg/L) increased to ≥ 4 mg/L with mutations in the four copies of the V domain of the 23S rRNA gene. The mRNA expression level of OG1RF_12220 (mdlB2, multidrug ABC superfamily ATP-binding cassette transporter) increased in the high-level linezolid-resistant isolates, and radezolid and linezolid MICs against the linezolid-sensitive isolate increased with overexpression of OG1RF_12220. Radezolid (at 1/4 or 1/8× the MIC) inhibited E. faecalis biofilm formation to a greater extent than linezolid, which was primarily achieved through the inhibition of ahrC, esp, relA, and relQ transcription in E. faecalis. In conclusion, radezolid is more effective than linezolid against planktonic E. faecalis cells and inhibits biofilm formation by this bacterium.}, } @article {pmid32117157, year = {2020}, author = {Fan, Y and Huang, X and Chen, J and Han, B}, title = {Formation of a Mixed-Species Biofilm Is a Survival Strategy for Unculturable Lactic Acid Bacteria and Saccharomyces cerevisiae in Daqu, a Chinese Traditional Fermentation Starter.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {138}, pmid = {32117157}, issn = {1664-302X}, abstract = {The existence and function of unculturable microorganisms are necessary to explain patterns of microbial diversity and investigate the assembly and succession of the complex microbial community. Chinese traditional alcoholic fermentation starter contains a complex microbial community harboring unculturable species that control the microbial diversity and have distinct functions. In this study, we revealed the presence, functions, and interactions of these unculturable species. Results of microbial diversity revealed by culture-dependent and metagenomic sequencing methods identified unculturable species and the potential functional species. Unculturable Saccharomyces cerevisiae and Lactobacillus sp. had a strong ability to form biofilms and co-existed as a mixed-species biofilm in the starter community. Using a hydrolase activity assay and fortified fermentation, we determined that the function of S. cerevisiae and Lactobacillus sp. to produce ethanol and flavor compounds. Widespread microbial interactions were identified among the biofilm isolates. S. cerevisiae was the main component of the biofilm and dominated the metabolic activities in the mixed-species biofilm. The environmental adaptability and biomass of Lactobacillus sp. were increased through its interaction with S. cerevisiae. The mixed biofilm of S. cerevisiae and Lactobacillus sp. also provides a tool for correlating microbial diversity patterns with their function in the alcoholic fermentation starter, and may provide a new understanding of fermentation mechanisms. Formation of a mixed-species biofilm represents a strategy for unculturable species to survive in competition with other microbes in a complex community.}, } @article {pmid32117136, year = {2020}, author = {Tkhilaishvili, T and Wang, L and Tavanti, A and Trampuz, A and Di Luca, M}, title = {Antibacterial Efficacy of Two Commercially Available Bacteriophage Formulations, Staphylococcal Bacteriophage and PYO Bacteriophage, Against Methicillin-Resistant Staphylococcus aureus: Prevention and Eradication of Biofilm Formation and Control of a Systemic Infection of Galleria mellonella Larvae.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {110}, pmid = {32117136}, issn = {1664-302X}, abstract = {Sessile bacteria growing on surfaces are more resistant to standard antibiotics than their planktonic counterpart. Due to their antimicrobial properties, bacteriophages have re-emerged as a promising approach to treat bacterial biofilm-associated infections. Here, we evaluated the ability of two commercially available phage formulations, Staphylococcal bacteriophage (containing the monophage Sb-1) and PYO bacteriophage (a polyphage), in preventing and eradicating an in vitro biofilm of methicillin-resistant Staphylococcus aureus (MRSA) by isothermal microcalorimetry and high-resolution confocal laser scanning microscopy (CLSM). Moreover, to assess the potential in vivo efficacy of both phage preparations, a Galleria mellonella model of MRSA systemic infection was used. Microcalorimetry measurement showed that 10[7] PFU/ml (the highest tested titer) of both phage formulations were able to inhibit planktonic growth in a concentration-dependent manner. However, MRSA biofilm was eradicated only by co-incubation of 5-7 days with the highest phage titers, respectively. In the experiments of biofilm prevention, isothermal microcalorimetry revealed that the heat production was completely abolished in the presence of sub-inhibitory titers (10[4] PFU/ml) of phages. These data were also confirmed by confocal laser scanning microscopy. Both phage formulations increased the survival of G. mellonella larvae preventing or treating MRSA infection compared to untreated control. In conclusion, tested phage formulations are promising for preventing device colonization and killing biofilm bacteria attached on a surface. Novel strategies for direct coating and release of phages from material should be investigated.}, } @article {pmid32117114, year = {2020}, author = {Başaran, TI and Berber, D and Gökalsın, B and Tramice, A and Tommonaro, G and Abbamondi, GR and Erginer Hasköylü, M and Toksoy Öner, E and Iodice, C and Sesal, NC}, title = {Extremophilic Natrinema versiforme Against Pseudomonas aeruginosa Quorum Sensing and Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {79}, pmid = {32117114}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes high morbidity and mortality rates due to its biofilm form. Biofilm formation is regulated via quorum sensing (QS) mechanism and provides up to 1000 times more resistance against conventional antibiotics. QS related genes are expressed according to bacterial population density via signal molecules. QS inhibitors (QSIs) from natural sources are widely studied evaluating various extracts from extreme environments. It is suggested that extremely halophilic Archaea may also produce QSI compounds. For this purpose, we tested QS inhibitory potentials of ethyl acetate extracts from cell free supernatants and cells of Natrinema versiforme against QS and biofilm formation of P. aeruginosa. To observe QS inhibition, all extracts were tested on P. aeruginosa lasB-gfp, rhlA-gfp, and pqsA-gfp biosensor strains and biofilm inhibition was studied using P. aeruginosa PAO1. According to our results, QS inhibition ratios of cell free supernatant extract (CFSE) were higher than cell extract (CE) on las system, whereas CE was more effective on rhl system. In addition, anti-biofilm effect of CFSE was higher than CE. Structural analysis revealed that the most abundant compound in the extracts was trans 4-(2-carboxy-vinyl) benzoic acid.}, } @article {pmid32117094, year = {2020}, author = {Peppoloni, S and Pericolini, E and Colombari, B and Pinetti, D and Cermelli, C and Fini, F and Prati, F and Caselli, E and Blasi, E}, title = {The β-Lactamase Inhibitor Boronic Acid Derivative SM23 as a New Anti-Pseudomonas aeruginosa Biofilm.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {35}, pmid = {32117094}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a Gram-negative nosocomial pathogen, often causative agent of severe device-related infections, given its great capacity to form biofilm. P. aeruginosa finely regulates the expression of numerous virulence factors, including biofilm production, by Quorum Sensing (QS), a cell-to-cell communication mechanism used by many bacteria. Selective inhibition of QS-controlled pathogenicity without affecting bacterial growth may represent a novel promising strategy to overcome the well-known and widespread drug resistance of P. aeruginosa. In this study, we investigated the effects of SM23, a boronic acid derivate specifically designed as β-lactamase inhibitor, on biofilm formation and virulence factors production by P. aeruginosa. Our results indicated that SM23: (1) inhibited biofilm development and production of several virulence factors, such as pyoverdine, elastase, and pyocyanin, without affecting bacterial growth; (2) decreased the levels of 3-oxo-C12-HSL and C4-HSL, two QS-related autoinducer molecules, in line with a dampened lasR/lasI system; (3) failed to bind to bacterial cells that had been preincubated with P. aeruginosa-conditioned medium; and (4) reduced both biofilm formation and pyoverdine production by P. aeruginosa onto endotracheal tubes, as assessed by a new in vitro model closely mimicking clinical settings. Taken together, our results indicate that, besides inhibiting β-lactamase, SM23 can also act as powerful inhibitor of P. aeruginosa biofilm, suggesting that it may have a potential application in the prevention and treatment of biofilm-associated P. aeruginosa infections.}, } @article {pmid32117092, year = {2020}, author = {Liu, L and Shen, X and Yu, J and Cao, X and Zhan, Q and Guo, Y and Yu, F}, title = {Subinhibitory Concentrations of Fusidic Acid May Reduce the Virulence of S. aureus by Down-Regulating sarA and saeRS to Reduce Biofilm Formation and α-Toxin Expression.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {25}, pmid = {32117092}, issn = {1664-302X}, abstract = {Staphylococcus aureus is an important pathogen in hospital and community infections. Fusidic acid is particularly effective in treating skin and wound infections caused by staphylococci. The purpose of our study was to clarify the effect of fusidic acid on the biofilm formation and α-toxin expression of S. aureus at subinhibitory concentrations [1/64, 1/32, and 1/16 × minimum inhibitory concentration (MIC)]. A total of 504 genes greater than a twofold or less than twofold change in expression of S. aureus effected by subinhibitory concentrations of fusidic acid were found, including 232 up-regulated genes and 272 down-regulated genes, which were determined by transcriptome sequencing. Our results showed subinhibitory concentrations of fusidic acid significantly inhibited the expression of hla, spa, icaA, and cidA at the mRNA level in clinical S. aureus strains tested. And subinhibitory concentrations of fusidic acid can significantly reduce the hemolysis activity and α-toxin production of S. aureus. In addition, the subinhibitory concentrations of fusidic acid significantly inhibited biofilm formation, autolysis, cell aggregation, and polysaccharide intercellular adhesin (PIA) production of S. aureus. Moreover, fusidic acid effectively reduces the damage of mouse skin lesion area. Furthermore, fusidic acid reduced the expression of the two-component regulatory system saeRS and staphylococcal accessory gene regulator (sarA). In conclusion, our results suggested that the subinhibitory concentrations of fusidic acid may reduce the virulence of S. aureus by down-regulating sarA and saeRS to reduce biofilm formation and α-toxin expression, which will provide a theoretical basis for the clinical treatment of S. aureus infection. This is the first report that fusidic acid has an inhibitory effect on the virulence of S. aureus, and this broadens the clinical application of fusidic acid.}, } @article {pmid32117086, year = {2019}, author = {Wang, Q and Yang, Q and Wu, W}, title = {Graphene-Based Steganographic Aptasensor for Information Computing and Monitoring Toxins of Biofilm in Food.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {3139}, pmid = {32117086}, issn = {1664-302X}, abstract = {Fungi-forming biofilm would produce various toxins in food. The toxin contamination will cause great harm to food and human health. Herein, a novel graphene-based steganographic aptasensor was assembled for multifunctional applications, which depended on the specific recognition and information encoding ability of DNA aptamers [mycotoxins, including zearalenone (ZEN) and ochratoxin A (OTA) aptamers, as models] and the selective absorption and fluorescence quenching capacities of graphene oxide (GO). The graphene-based steganographic aptasensor can be regarded as an information encryption and steganographic system using GO as a cover, aptamers for specific target recognition as information carriers and dual targets (ZEN and OTA) as special keys. In our work, the fluorescence of capture probes (Cy3 aptamer and Alexa Fluor 488 aptamer) was quenched by GO to realize information encryption. In the presence of dual targets in the GO-APT solution, Cy3 aptamer (APT1), and Alexa Fluor 488 aptamer (APT2) were released from the surface of GO, decrypting the hidden information. In addition, our work offers a sensor for rapid and sensitive simultaneous fluorescence determination of ZEN and OTA. The detection limit of the aptasensor was 1.797 ng/ml for ZEN and 1.484 ng/ml for OTA. In addition, the graphene-based steganographic aptasensor can be used to construct a molecular logic gate system in which GO, aptamers, and mycotoxins are employed as the input and compounds and fluorescence signals were used as the output. This would be helpful to control the biofilm toxin in the future.}, } @article {pmid32114965, year = {2021}, author = {Naresh Yadav, D and Naz, I and Anand Kishore, K and Saroj, D}, title = {Evaluation of tire derived rubber (TDR) fixed biofilm reactor (FBR) for remediation of Methylene blue dye from wastewater.}, journal = {Environmental technology}, volume = {42}, number = {23}, pages = {3627-3640}, doi = {10.1080/09593330.2020.1737736}, pmid = {32114965}, issn = {1479-487X}, mesh = {Biodegradation, Environmental ; Biofilms ; *Methylene Blue ; Rubber ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The present investigation is focused on development of aerobic biofilm on tire-derived rubber (TDR) media and then evaluation of such system for bioremediation of Methylene blue (MB) dye for 9 weeks. After 9 weeks of operation, the COD, BOD, ammonia and color values have been declined by 89.2%, 98.3%, 99.61% and 99.81%, respectively, While SEM-EDX results showed a variance in weight percent of various elements in TDR without biofilm i.e. raw TDR media, as well as in the 1st and 9th-week samples. Moreover, fine and strong peaks were observed in both the MB simulated wastewater and 9th week TDR samples at 1190, 1300, 1400, 1450, 1500 and 1618 cm[-1] respectively by Raman Spectroscopic analysis. Further, FTIR analysis was performed for the MB simulated wastewater, and absorbance peaks ranging from 1591 to 1363 cm[-1] and 3410 cm[-1] were observed in all the samples with different intensities. To assess the biodeterioration of the TDR media, ATR was performed for the raw, 1st, 2nd and 9th week TDR media samples and in the raw TDR, two important bands, 842 and 2962 cm[-1] were noticed representing -CH = CH and -CH3. A clear variation of bands and peak intensities were observed in different support media samples. The results indicate that TDR media is a resilient, chemically resistant material and could be employed for the biofilm growth for biological treatment of textile dye wastewater.}, } @article {pmid32112948, year = {2020}, author = {Gu, W and Wang, L and Liu, Y and Liang, P and Zhang, X and Li, Y and Huang, X}, title = {Anammox bacteria enrichment and denitrification in moving bed biofilm reactors packed with different buoyant carriers: Performances and mechanisms.}, journal = {The Science of the total environment}, volume = {719}, number = {}, pages = {137277}, doi = {10.1016/j.scitotenv.2020.137277}, pmid = {32112948}, issn = {1879-1026}, mesh = {Ammonium Compounds ; Bacteria ; Biofilms ; Bioreactors ; *Denitrification ; Nitrogen ; Oxidation-Reduction ; Sewage ; Wastewater ; }, abstract = {Anaerobic ammonium oxidation (anammox) is recognized as the most cost-effective process for nitrogen removal from wastewater. In this study, effects of polyethylene plastics, nonwoven fabric, granular activated carbon (GAC) and polyurethane sponge as buoyant carriers were evaluated in lab-scale moving bed biofilm reactors (MBBRs). The overall performance of MBBRs with four types of carriers from priority to inferiority was noticed as, GAC, nonwoven fabrics, polyurethane sponge and polyethylene plastics under the same packing ratio of 20 v% and an average carrier size of 4 × 4 × 4 mm. The hydrophobic surface of GAC could selectively adsorb hydrophobic protein and favor anammox bacteria attachment, which contributed to achieving a total nitrogen removal rate of 0.40 kg-N/(m[3]·d) in 60 days. In conclusion, our results provide compelling evidence for achieving effective anammox process in an MBBR with GAC carriers and would benefit towards accomplishing a stable partial nitritation-anammox process in the future.}, } @article {pmid32111586, year = {2020}, author = {Souza, JGS and Bertolini, M and Thompson, A and Barão, VAR and Dongari-Bagtzoglou, A}, title = {Biofilm Interactions of Candida albicans and Mitis Group Streptococci in a Titanium-Mucosal Interface Model.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {9}, pages = {}, pmid = {32111586}, issn = {1098-5336}, support = {R01 DE013986/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Candida albicans/*physiology ; Humans ; Mouth Mucosa/*microbiology ; Streptococcus gordonii/*physiology ; Titanium/*physiology ; Viridans Streptococci/*physiology ; }, abstract = {Streptococci from the mitis group (represented mainly by Streptococcus mitis, Streptococcus oralis, Streptococcus sanguinis, and Streptococcus gordonii) form robust biofilms with Candida albicans in different experimental models. These microorganisms have been found in polymicrobial biofilms forming on titanium biomaterial surfaces in humans with peri-implant disease. The purpose of this work was to study mutualistic interactions in biofilms forming on titanium and their effect on the adjacent mucosa, using a relevant infection model. Single and mixed biofilms of C. albicans and each Streptococcus species were grown on titanium disks. Bacterial and fungal biovolume and biomass were quantified in these biofilms. Organotypic mucosal constructs were exposed to preformed titanium surface biofilms to test their effect on secretion of proinflammatory cytokines and cell damage. C. albicans promoted bacterial biofilms of all mitis Streptococcus species on titanium surfaces. This relationship was mutualistic since all bacterial species upregulated the efg1 hypha-associated gene in C. albicans Mixed biofilms caused increased tissue damage but did not increase proinflammatory cytokine responses compared to biofilms comprising Candida alone. Interestingly, spent culture medium from tissues exposed to titanium biofilms suppressed Candida growth on titanium surfaces.IMPORTANCE Our findings provide new insights into the cross-kingdom interaction between C. albicans and Streptococcus species representative of the mitis group. These microorganisms colonize titanium-based dental implant materials, but little is known about their ability to cause inflammation and damage of the adjacent mucosal tissues. Using an in vitro biomaterial-mucosal interface infection model, we showed that mixed biofilms of each species with C. albicans enhance tissue damage. One possible mechanism for this effect is the increased fungal hypha-associated virulence gene expression we observed in mixed biofilms with these species. Interestingly, we also found that the interaction of multispecies biofilms with organotypic mucosal surfaces led to the release of growth-suppressing mediators of Candida, which may represent a homeostatic defense mechanism of the oral mucosa against fungal overgrowth. Thus, our findings provide novel insights into biofilms on biomaterials that may play an important role in the pathogenesis of mucosal infections around titanium implants.}, } @article {pmid32109809, year = {2020}, author = {Zhang, L and Zhang, Y and Patterson, J and Arslan, M and Zhang, Y and Gamal El-Din, M}, title = {Biofiltration of oil sands process water in fixed-bed biofilm reactors shapes microbial community structure for enhanced degradation of naphthenic acids.}, journal = {The Science of the total environment}, volume = {718}, number = {}, pages = {137028}, doi = {10.1016/j.scitotenv.2020.137028}, pmid = {32109809}, issn = {1879-1026}, mesh = {Biodegradation, Environmental ; Biofilms ; Carboxylic Acids ; Filtration ; *Microbiota ; Oil and Gas Fields ; Ozone ; Water Pollutants, Chemical ; }, abstract = {Naphthenic acids (NAs) are a complex mixture of carboxylic acids present in oil sands process water (OSPW). Their recalcitrant nature makes them difficult to be removed from the environment using conventional remediation strategies. This study hypothesized that, upon continuous operation, biofiltration of OSPW in fixed-bed biofilm reactors would allow the development of NA-degrading microbial community within the biofilter following successful removal. Both raw and ozonated OSPW were treated in the biofilters and changes in microbial community were tested via 16S/18S amplicon sequencing and metatranscriptomics. Through switch from suspended growth to attached growth, a shift in indigenous microbial community was seen following by an increase in alpha diversity. Concomitantly, improved degradation of NAs was monitored, i.e., 35.8% and 69.4% of NAs were removed from raw and ozonated OSPW, respectively. Metatranscriptomics analysis suggested the presence of genes involved in the degradation of organic acids and petroleum-related compounds. Specifically, functional abundance of aromatic compounds' metabolism improved from 0.05% to 0.76%; whereas abundance of benzoate transport and degradation pathway increased from 0.04% to 0.64%. These changes conclude that continuous operation of OSPW in the bioreactors was in favor of shaping the overall microbiome towards better NA degradation.}, } @article {pmid32109732, year = {2020}, author = {Almomani, F and Bohsale, RR}, title = {Optimizing nutrient removal of moving bed biofilm reactor process using response surface methodology.}, journal = {Bioresource technology}, volume = {305}, number = {}, pages = {123059}, doi = {10.1016/j.biortech.2020.123059}, pmid = {32109732}, issn = {1873-2976}, abstract = {The potential of 3-stages process (anaerobic, anoxic and moving bed biofilm reactor (MBBR)) for organic matter and nutrient removals from secondary WWTP effluents at various hydraulic retention time (HRT) and nitrate recycle ratio (R) was investigated. Percentage removals of total nitrogen (%TNremoval) and phosphorous (%TPremoval) were optimized using response surface methodology (RSM). Under optimized conditions (HRTtotal = 12.8 hr and R = 1.5) significant chemical oxygen demand removal (%CODremoval), %TNremoval and %TPremoval of 95.5%, 96.2%, 94.70% were attained. The MMBR effectively reduced organic matter and nutrient under low HRT and R. %TNremoval was improved by increasing the HRTR2 up to 1.5 h at R ≤ 2. Bio-uptake of phosphorus and nitrate is controlled by release of secondary phosphorous. Reactors demonstrated stable biofilm characteristics except for a slight decrease in biofilm thickness due to flow-shear stress. The 3-stages process performed four times higher than suspended growth process and similar to 5-stage Bardenpho-MBBR.}, } @article {pmid32109606, year = {2020}, author = {Haghi Ghahremanloi Olia, A and Ghahremani, M and Ahmadi, A and Sharifi, Y}, title = {Comparison of biofilm production and virulence gene distribution among community- and hospital-acquired Staphylococcus aureus isolates from northwestern Iran.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {81}, number = {}, pages = {104262}, doi = {10.1016/j.meegid.2020.104262}, pmid = {32109606}, issn = {1567-7257}, mesh = {Adhesins, Bacterial/genetics ; Biofilms/*growth & development ; Community-Acquired Infections/*microbiology ; Genes, Bacterial/genetics ; Hospitals ; Humans ; Iran ; Methicillin Resistance/genetics ; Methicillin-Resistant Staphylococcus aureus/*genetics ; Staphylococcal Infections/microbiology ; Virulence/*genetics ; Virulence Factors/*genetics ; }, abstract = {INTRODUCTION: The emergence of antimicrobial-resistant isolates among Staphylococcus aureus and their genetic variations has become a major concern worldwide. The present study aims at comparing the biofilm formation and the genes encoding adhesion molecules in methicillin-susceptible, community- and hospital-acquired methicillin-resistant, vancomycin-intermediate and vancomycin-resistant S. aureus isolates.

METHODOLOGY: The current study was conducted on 60 S.aureus isolates, collected at Urmia University of Medical Sciences, Iran, between the years 2014 and 2015. The modified Congo-red agar and Microtiter plate methods were used to determine biofilm production. PCR was used to detect the genes which were associated with a protein family of staphylococcal microbial surface components recognizing adhesive matrix molecules. The data were analyzed using SPSS (IBM SPSS Statistics, version 16).

RESULTS: Of 60 isolates, 57 (95%) were biofilm producers. Unlike the bbp gene, which was only detected in 3 (5%) isolates, the eno and icaD genes were identified as the most prevalent as they were detected in 53 (88.3%) and 50 (85%) of 60 isolates, respectively. The dominant virulotype comprised eight genes (icaA, icaD, clfA, clfB, fnbA, cna, eno, ebpS) in eight isolates, six of which were community-acquired-MRSAs.

CONCLUSION: A high percentage of the S. aureus isolates could produce a biofilm which is more common among methicillin-susceptible isolates. The high frequency of eno and icaD genes suggests that these genes may synergistically function in the onset and progression of bacterial colonization and biofilm formation. Meanwhile, this ability may help the bacteria resist the exposure of antibacterial agents and cause severe infections.}, } @article {pmid32108951, year = {2020}, author = {Soares, RB and Costa, DH and Miyakawa, W and Delgado, MGT and Garcez, AS and Yoshimura, TM and Ribeiro, MS and Nunez, SC}, title = {Photodynamic Activity on Biofilm in Endotracheal Tubes of Patients Admitted to an Intensive Care Unit.}, journal = {Photochemistry and photobiology}, volume = {96}, number = {3}, pages = {618-624}, doi = {10.1111/php.13239}, pmid = {32108951}, issn = {1751-1097}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; Humans ; *Intensive Care Units ; Intubation, Intratracheal/adverse effects/*instrumentation ; Microscopy, Electron, Scanning ; *Photochemotherapy ; Pseudomonas aeruginosa/*drug effects/growth & development/isolation & purification ; }, abstract = {Ventilator-associated pneumonia (VAP) is an infection that arises after endotracheal intubation affecting patients under intensive care. The presence of the endotracheal tube (ETT) is a risk factor since it is colonized by multispecies biofilm. Antimicrobial photodynamic therapy (aPDT) could be a strategy to decontaminate ETTs. We verify if methylene blue (MB) associated with external illumination of the ETT could be an alternative to destroy biofilm. We performed an in vitro and ex vivo study. In vitro study was performed with P. aeruginosa biofilm grew over ETT for 7 days. After treatment, the surviving cells were cultured for 3 days and the biofilm was analyzed by crystal violet absorbance. Ex vivo study employed ETT obtained from extubated patients. aPDT was performed with MB (100 µm) and red LED (λ = 640±20 nm). We quantified the biofilm thickness and used scanning electron microscopy and fluorescence technique to verify morphological and functional changes after aPDT. Our results showed that bacteria remain susceptible to aPDT after sequential treatments. We also attested that aPDT can reduce biofilm thickness, disrupt biofilm attachment from ETT surface and kill microbial cells. These data suggest that aPDT should be investigated to decrease VAP incidence via ETT decontamination.}, } @article {pmid32107915, year = {2020}, author = {Zhu, Z and Chen, Y and Li, S and Lin, H and Qin, G and Cai, C}, title = {Ortho-Substituted α-Phenyl Mannoside Derivatives Promoted Early-Stage Adhesion and Biofilm Formation of E. coli 83972.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {19}, pages = {21300-21310}, doi = {10.1021/acsami.9b17868}, pmid = {32107915}, issn = {1944-8252}, mesh = {Adhesins, Escherichia coli/metabolism ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Escherichia coli/*drug effects/physiology ; Fimbriae Proteins/metabolism ; Flow Cytometry ; Mannosides/chemical synthesis/metabolism/*pharmacology ; Protein Binding ; Silicones/chemistry ; }, abstract = {Prevention of catheter-associated urinary tract infection (CAUTI) over long-term usage of urinary catheters remains a great challenge. Bacterial interference using nonpathogenic bacteria, such as E. coli 83972, have been investigated in many pilot-scale clinical studies as a potentially nonantibiotic based strategy for CAUTI prevention. We have demonstrated that preforming a dense and stable biofilm of the nonpathogenic E. coli greatly enhances their capability to prevent pathogen colonization. Such nonpathogenic biofilms were formed by E. coli 83972 expressing type 1 fimbriae (fim+ E. coli 83972) on mannoside-presenting surfaces. In this work, we report the synthesis of a series of mannoside derivatives with a wide range of binding affinities, all being equipped with a handle for covalent attachment to silicone surfaces. We established a high-throughput competitive assay based on mannoside-modified particles and flow-cytometry to directly measure the binding affinity between the mannoside ligands and fim+ E. coli 83972. We demonstrated that the bacterial adhesion and biofilm formation were strongly correlated to the binding affinity of the immobilized mannoside ligands. Mass spectrometry based proteomic analysis indicated a substantial difference in the proteome of the extracellular polymeric substance (EPS) secreted by biofilms on different mannoside surfaces, which might be related to the biofilm stability.}, } @article {pmid32106606, year = {2020}, author = {Park, KM and Kim, HJ and Jeong, M and Koo, M}, title = {Enterotoxin Genes, Antibiotic Susceptibility, and Biofilm Formation of Low-Temperature-Tolerant Bacillus cereus Isolated from Green Leaf Lettuce in the Cold Chain.}, journal = {Foods (Basel, Switzerland)}, volume = {9}, number = {3}, pages = {}, pmid = {32106606}, issn = {2304-8158}, abstract = {The prevalence and characteristics of low-temperature-tolerant Bacillus cereus (psychrotolerant B. cereus) in green leaf lettuce collected during cold chain were investigated. Among the 101 isolated B. cereus samples, only 18 were capable of growth at 7 °C, and these isolates shared potential health hazard characteristics with mesophilic isolates. Most psychrotolerant B. cereus isolates contained various combinations of nheA, nheB, nheC, hblA, hblA, hblC, hblD, cytK, and entFM. Most isolates of psychrotolerant B. cereus possessed at least two enterotoxin genes and 28% of isolates harbored tested nine enterotoxin genes. Additionally, the psychrotolerant B. cereus isolates showed resistance to tetracycline and rifampin and intermediate levels of resistance to clindamycin. A total of 23% of isolates among psychrotolerant B. cereus displayed a high level of biofilm formation at 7 °C than at 10 °C or 30 °C. The results of this study indicate that cold distribution and storage for green leaf lettuce may fail to maintain food safety due to the presence of enterotoxigenic, antibiotic-resistant, and strong biofilm forming psychrotolerant B. cereus isolates, which therefore poses a potential health risk to the consumer. Our findings provide the first account of the prevalence and characteristics of psychrotolerant B. cereus isolated from green leaf lettuce during cold storage, suggesting a potential hazard of psychrotolerant B. cereus isolates to public health and the food industry.}, } @article {pmid32106485, year = {2020}, author = {Gulías, Ò and McKenzie, G and Bayó, M and Agut, M and Nonell, S}, title = {Effective Photodynamic Inactivation of 26 Escherichia coli Strains with Different Antibiotic Susceptibility Profiles: a Planktonic and Biofilm Study.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {3}, pages = {}, pmid = {32106485}, issn = {2079-6382}, support = {CTQ2016-78454-C2-1-R//Ministerio de Ciencia, Innovación y Universidades/ ; CTQ2013-48767-C3-1-R//Ministerio de Ciencia, Innovación y Universidades/ ; }, abstract = {The emergence of multidrug-resistant bacteria is a growing problem and alternative therapies are being sought to effectively address this issue. The aim of this study is to assess a range of Escherichia coli strains' susceptibility to Methylene Blue-mediated antimicrobial photodynamic therapy and determine if this is affected by their antibiotic-resistance profile. Two reference and twenty-four uropathogenic clinical E. coli strains were used in this study. All were tested in vitro for antimicrobial susceptibility against sixteen antibiotics. Strains underwent photodynamic treatments using the photosensitizer Methylene Blue with red light and tested in both planktonic and biofilm state. It was found that reference strain ATCC 25922 was susceptible to all tested antibiotics whereas reference strain ATCC 35218 showed resistance only to Ampicillin. With the exception of strains number 16 and 22, all of the isolated strains were multidrug-resistant according to the criteria established by the European Centre for Disease Prevention and Control and the Centre for Disease Control and Prevention, where acquired non-susceptibility to at least one agent in three or more antimicrobial categories is outlined. Photodynamic therapy induced more than 3 log10 colony-forming units' reduction to all strains in planktonic state. Whereas when tested in biofilm state, two and a half times the original dose of methylene blue was necessary to cause a 3 log10 antimicrobial effect. There were statistically significant differences in susceptibility among the strains tested in both the planktonic and biofilm experiments. Nevertheless, antimicrobial photodynamic therapy could inactivate all multidrug-resistant strains in the planktonic and biofilm state.}, } @article {pmid32105802, year = {2020}, author = {Li, Y and Xia, H and Bai, F and Song, X and Zhuang, L and Xu, H and Zhang, X and Zhang, X and Qiao, M}, title = {PA5001 gene involves in swimming motility and biofilm formation in Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {144}, number = {}, pages = {103982}, doi = {10.1016/j.micpath.2020.103982}, pmid = {32105802}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics ; Base Sequence ; Biofilms/*growth & development ; Flagella/physiology ; Gene Deletion ; Gene Expression Regulation, Bacterial/genetics ; Gene Knockout Techniques ; Humans ; Locomotion/*genetics ; Microscopy, Electron, Transmission ; Plasmids/genetics ; Pseudomonas Infections/pathology ; Pseudomonas aeruginosa/*genetics/isolation & purification/physiology ; Sequence Analysis, DNA ; }, abstract = {Pseudomonas aeruginosa is a nosocomial human pathogen causing infections in immunocompromised patients. To explore new genes involved in P. aeruginosa swimming motility, Mu transposon mutagenesis library was screened for isolates with altered swimming motility. Eleven nonmobile mutants were identified. Sequence analysis shows the nonmobile phenotype of one isolate was attributed to the inactivation of PA5001 gene. PA5001 knockout mutant based on the PAK lab strain also displayed comparable phenotypes suggesting the universal gene function regardless of strain. Exotic PA5001 gene fragment provided on expressing plasmid was capable of storing nonmobile phenotype of PA5001 mutant, suggesting the functional involvement of PA5001 gene on bacterial swimming. Impact of PA5001 inactivation on biofilm formation was examined, as adhesion and interaction during biofilm formation is highly dependent of bacterial mobility. The result shows that normal architecture of biofilm was disrupted in the mutant. Complementing by exotic PA5001 gene fragment resulted in the restoration of biofilm phenotype. Our results provide evidences suggesting the functional participation of PA5001 gene in bacterial mobility and biofilm formation. The critical function by PA5001 in bacterial motility and biofilm might serve as hint for the novel target for the treatment of chronic infections caused by P. aeruginosa.}, } @article {pmid32105313, year = {2020}, author = {Ricciardelli, A and Casillo, A and Corsaro, MM and Tutino, ML and Parrilli, E and van der Mei, HC}, title = {Pentadecanal and pentadecanoic acid coatings reduce biofilm formation of Staphylococcus epidermidis on PDMS.}, journal = {Pathogens and disease}, volume = {78}, number = {3}, pages = {}, doi = {10.1093/femspd/ftaa012}, pmid = {32105313}, issn = {2049-632X}, mesh = {Aldehydes/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Coated Materials, Biocompatible/*pharmacology ; Dimethylpolysiloxanes/chemistry ; Equipment and Supplies/microbiology ; Fatty Acids/*pharmacology ; Staphylococcus epidermidis/*drug effects ; }, abstract = {Staphylococcus epidermidis is well known to be one of the major causes of infections related to medical devices, mostly due to its strong capacity to form device-associated biofilms. Nowadays, these infections represent a severe burden to the public health system and the necessity of novel antibacterial strategies for the treatment of these difficult-to-eradicate infections is urgent. The Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 was found to be able to produce an anti-biofilm molecule, the pentadecanal, active against S. epidermidis. In this work, we modified one of the most widely used silicone-based polymers, polydimethylsiloxane (PDMS), by adsorption of pentadecanal and its most promising derivative, pentadecanoic acid, on the PDMS surface. The biofilm formation of S. epidermidis RP62A on both untreated and modified PDMS was performed in a parallel plate flow chamber system, demonstrating the capability of the proposed anti-biofilm coatings to strongly reduce the biofilm formation. Furthermore, drug-release capacity and long-term efficacy (21 days) were also proven for the pentadecanoic acid coating.}, } @article {pmid32104742, year = {2019}, author = {Modiri, M and Hashemi, SJ and GhazvinI, RD and Khodavaisy, S and Ahmadi, A and Ghaffari, M and Rezaie, S}, title = {Antifungal susceptibility pattern and biofilm-related genes expression in planktonic and biofilm cells of Candida parapsilosis species complex.}, journal = {Current medical mycology}, volume = {5}, number = {4}, pages = {35-42}, pmid = {32104742}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: Candida parapsilosis complex isolates are mainly responsible for nosocomial catheter-related infection in immunocompromised patients. Biofilm formation is regarded as one of the most pertinent key virulence factors in the development of these emerging infections. The present study aimed to compare in vitro antifungal susceptibility patterns and biofilm-related genes expression ratio in planktonic and biofilm's cells of clinically C. parapsilosis complex isolates.

MATERIALS AND METHODS: The current study was conducted on a number of 17 clinical C. parapsilosis complex (10 C. parapsilosis sensu stricto, 5 C. orthopsilosis, and 2 C. metapsilosis). The antifungal susceptibility patterns of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin in planktonic and biofilm forms were closely examined using CLSI M27-A3 broth microdilution method. The expression levels of biofilm-related genes (BCR1, EFG1, and FKS1) were evaluated in planktonic and biofilm's cells using Real-time polymerase chain reaction (PCR) technique.

RESULTS: The obtained results indicated that all C. parapsilosis complex isolates were able to produce high and moderate amounts of biofilm forms. In addition, the sessile minimum inhibitory concentrations were reported to be high for fluconazole (≥ 64 µg/ml), itraconazole, voriconazole, and posaconazole (≥ 16 µg/ml), as compared to planktonic minimum inhibitory concentrations. Moreover, a significant difference was observed between antifungal susceptibility patterns for all azole antifungal agents (P<0.05). Furthermore, the BCR1 overexpression was considered significant in biofilms with regard to planktonic cells in C. parapsilosis species complex (P=0.002).

CONCLUSION: C. parapsilosis complex isolates were found susceptible to most of the tested antifungal drugs, while biofilms demonstrated a noticeable resistant to azoles. The marked discrepancy noted in antifungal susceptibility patterns among these species should be highlighted to achieve effective therapeutic treatment.}, } @article {pmid32103775, year = {2020}, author = {Mirzaei, B and Faridifar, P and Shahmoradi, M and Shapouri, R and Iranpour, F and Haghi, F and Ezzedin, M and Babaei, R and Mousavi, SF}, title = {Genotypic and phenotypic analysis of biofilm formation Staphylococcus epidermidis isolates from clinical specimens.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {114}, pmid = {32103775}, issn = {1756-0500}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Drug Resistance, Bacterial/*genetics ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phenotype ; Polymerase Chain Reaction ; Prosthesis-Related Infections/microbiology ; Staphylococcal Infections/blood/microbiology/urine ; Staphylococcus epidermidis/classification/*genetics/physiology ; }, abstract = {OBJECTIVES: Staphylococcus epidermidis is the primary causative agent of infections associated with indwelling biomaterials. Antibiotic susceptibility patterns, Biofilm formation capability, and screening of responsible genes in biofilm formation procedure in clinical isolates (icaA, icaB, icaC, icaD, sdrG, and atlE) were assigned as the main objectives in this study. The clinical samples were analyzed via standard biochemical assays for identifying different bacteria which were confirmed using the multiplex colony PCR method. Subsequently, biofilm-formation capability, antibiotic susceptibility testing, and the frequency of genes responsible for biofilm formation in the confirmed strains were checked.

RESULTS: Out of 183 clinical specimens 54 S. epidermidis isolates were detected by targeting a housekeeping gene (sesc) taking advantage of the PCR procedure. All of the strains were Biofilm forming producers. The in vitro biofilm formation assays determined that 45 (83.33%), 5 (9.26%), 4 (7.41%) were strong, moderate, and weak biofilm former strains respectively. Among the isolated strains, the specific frequencies of the biofilm-forming genes were specified to be (98%) for sdrG, (84%) for atlE, (80%) for icaC, and (70%) for icaD. Cefamandole and Amikacin are the most effective antibiotics in isolated strains. All strains were ascertained to be methicillin and amoxicillin/clavulanic acid resistant.}, } @article {pmid32102851, year = {2020}, author = {Yarawsky, AE and Johns, SL and Schuck, P and Herr, AB}, title = {The biofilm adhesion protein Aap from Staphylococcus epidermidis forms zinc-dependent amyloid fibers.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {14}, pages = {4411-4427}, pmid = {32102851}, issn = {1083-351X}, support = {R01 GM094363/GM/NIGMS NIH HHS/United States ; U19 AI070235/AI/NIAID NIH HHS/United States ; }, mesh = {Amyloid/*metabolism ; Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Chelating Agents/chemistry ; Microscopy, Confocal ; Pentetic Acid/pharmacology ; Protein Binding ; Protein Domains ; Protein Folding ; Recombinant Fusion Proteins/biosynthesis/chemistry/isolation & purification ; Staphylococcus epidermidis/*physiology ; Temperature ; Zinc/chemistry/*metabolism ; }, abstract = {The skin-colonizing commensal bacterium Staphylococcus epidermidis is a leading cause of hospital-acquired and device-related infections. Its pathogenicity in humans is largely due to its propensity to form biofilms, surface-adherent bacterial accumulations that are remarkably resistant to chemical and physical stresses. Accumulation-associated protein (Aap) from S. epidermidis has been shown to be necessary and sufficient for mature biofilm formation and catheter infection. Aap contains up to 17 tandem B-repeat domains, capable of zinc-dependent assembly into twisted, rope-like intercellular filaments in the biofilm. Using microscopic and biophysical techniques, we show here that Aap B-repeat constructs assemble further into zinc-dependent functional amyloid fibers. We observed such amyloid fibers by confocal microscopy during both early and late stages of S. epidermidis biofilm formation, and we confirmed that extracellular fibrils from these biofilms contain Aap. Unlike what has been observed for amyloidogenic biofilm proteins from other bacteria, which typically use chaperones or initiator proteins to initiate amyloid assembly, our findings indicate that Aap from S. epidermidis requires Zn[2+] as a catalyst that drives amyloid fiber formation, similar to many mammalian amyloid-forming proteins that require metals for assembly. This work provides detailed insights into S. epidermidis biofilm formation and architecture that improve our understanding of persistent staphylococcal infections.}, } @article {pmid32102470, year = {2020}, author = {Achek, R and Hotzel, H and Nabi, I and Kechida, S and Mami, D and Didouh, N and Tomaso, H and Neubauer, H and Ehricht, R and Monecke, S and El-Adawy, H}, title = {Phenotypic and Molecular Detection of Biofilm Formation in Staphylococcus aureus Isolated from Different Sources in Algeria.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {2}, pages = {}, pmid = {32102470}, issn = {2076-0817}, abstract = {Staphylococcus aureus is an opportunistic bacterium causing a wide variety of diseases. Biofilm formation of Staphylococcus aureus is of primary public and animal health concern. The purposes of the present study were to investigate the ability of Staphylococcus aureus isolated from animals, humans, and food samples to form biofilms and to screen for the presence of biofilm-associated and regulatory genes. In total, 55 Staphylococcus aureus isolated from sheep mastitis cases (n = 28), humans (n = 19), and from food matrices (n = 8) were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The ability of Staphylococcus aureus for slime production and biofilm formation was determined quantitatively. A DNA microarray examination was performed to detect adhesion genes (icaACD and biofilm-associated protein gene (bap)), genes encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), regulatory genes (accessory gene regulator (agr) and staphylococcal accessory regulator (sarA)), and the staphylococcal cassette chromosome mec elements (SCCmec). Out of 55 Staphylococcus aureus isolates, 39 (71.0%) and 23 (41.8%) were producing slime and biofilm, respectively. All Staphylococcus aureus strains isolated from food showed biofilm formation ability. 52.6% of the Staphylococcus aureus strains isolated from sheep with mastitis, and 17.9% of isolates from humans, were able to form a biofilm. Microarray analysis typed the Staphylococcus aureus into 15 clonal complexes. Among all Staphylococcus aureus isolates, four of the human isolates (21.1%) harbored the mecA gene (SCCmec type IV) typed into 2 clonal complexes (CC22-MRSA-IV and CC80-MRSA-IV) and were considered as methicillin-resistant, while two of them were slime-producing. None of the isolates from sheep with mastitis harbored the cna gene which is associated with biofilm production. The fnbB gene was found in 100%, 60% and 40% of biofilm-producing Staphylococcus aureus isolated from food, humans, and sheep with mastitis, respectively. Three agr groups were present and agr group III was predominant with 43.6%, followed by agr group I (38.2%), and agr group II (18.2%). This study revealed the capacity of Staphylococcus aureus isolates to form biofilms and highlighted the genetic background displayed by Staphylococcus aureus isolates from different sources in Algeria.}, } @article {pmid32102181, year = {2020}, author = {Majtan, J and Sojka, M and Palenikova, H and Bucekova, M and Majtan, V}, title = {Vitamin C Enhances the Antibacterial Activity of Honey against Planktonic and Biofilm-Embedded Bacteria.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {4}, pages = {}, pmid = {32102181}, issn = {1420-3049}, support = {VEGA 2/0004/18//Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Ascorbic Acid/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Catalase/metabolism ; Escherichia coli/drug effects ; Heating ; *Honey ; Hydrogen Peroxide/metabolism/pharmacology ; Microbial Sensitivity Tests ; Plankton/*microbiology ; Staphylococcus aureus/drug effects ; }, abstract = {Multifactorial antibacterial action is an important feature of honey; however, its bactericidal efficacy against biofilm-embedded bacteria is limited. The aim of this study was to investigate the impact of vitamin C (Vit C) on the antibacterial activity of natural honeys against planktonic as well as biofilm-embedded bacterial pathogens. The antibacterial activity of four honey samples supplemented with Vit C was expressed as the minimum inhibitory concentration (MIC). At sub-MICs, Vit C significantly increased the antibacterial activity of the tested honeys against Pseudomonas aeruginosa in planktonic cultures. However, after supplementation, honeydew honey, the most active honey, was ineffective against Staphylococcus aureus. On the other hand, when 100% honeydew honey was supplemented with Vit C (100 mg/g of honey) in a multispecies wound biofilm model, complete eradication of almost all bacterial isolates, including S. aureus, was observed. Furthermore, a mixture of honey and Vit C was partially effective against Enterococcus faecalis, whereas honey alone exhibited no antibacterial activity against this bacterium. Vit C counteracted hydrogen peroxide in honey solution and, thus, eliminated the major antibacterial compound present in honey. It is likely that a combination of honey with Vit C may trigger the intracellular production of reactive oxygen species in bacterial cells, but the exact cellular mechanisms warrant further investigations.}, } @article {pmid32100933, year = {2020}, author = {Abdulkareem, AA and Al Marah, ZA and Abdulbaqi, HR and Alshaeli, AJ and Milward, MR}, title = {A randomized double-blind clinical trial to evaluate the efficacy of chlorhexidine, antioxidant, and hyaluronic acid mouthwashes in the management of biofilm-induced gingivitis.}, journal = {International journal of dental hygiene}, volume = {18}, number = {3}, pages = {268-277}, doi = {10.1111/idh.12432}, pmid = {32100933}, issn = {1601-5037}, mesh = {*Anti-Infective Agents, Local ; Antioxidants ; Biofilms ; Chlorhexidine ; *Dental Plaque ; Dental Plaque Index ; Double-Blind Method ; *Gingivitis ; Humans ; Hyaluronic Acid ; Mouthwashes ; }, abstract = {OBJECTIVES: To investigate the antiplaque and antigingivitis efficacy in addition to evaluating side effects and subjects' perceptions of three commercially available mouthwashes.

METHODS: This study was a double-blind, parallel, and short-term trial. A total of 75 dental students with biofilm-induced gingivitis were included in the final analysis of the current study. Clinical parameters (plaque index and bleeding on probing) and the staining effect were measured at baseline and after 7 days. In addition, a VAS-based assessment questionnaire was completed by the participants.

RESULTS: All interventions significantly reduced plaque scores, but chlorhexidine (CHX) had a significantly higher effect than the hyaluronic acid (HA) and antioxidant mouthwashes. However, all mouthwashes significantly reduced the total bleeding scores to <10% in 53% of the patients, compared to the baseline record. Additionally, teeth underwent shade changes in association with all interventions by the end of the study. Analysis of feedback about the mouthwashes showed that the participants seemed to prefer the HA mouthwash over the other mouthwashes.

CONCLUSIONS: CHX remains the most effective antiplaque mouthwash although HA and antioxidants are as effective as CHX in reducing bleeding. In addition, based on its better acceptance by the participants, HA is potentially a good alternative to CHX.}, } @article {pmid32097807, year = {2020}, author = {Xu, X and Zhu, J and Thies, JE and Wu, W}, title = {Methanol-linked synergy between aerobic methanotrophs and denitrifiers enhanced nitrate removal efficiency in a membrane biofilm reactor under a low O2:CH4 ratio.}, journal = {Water research}, volume = {174}, number = {}, pages = {115595}, doi = {10.1016/j.watres.2020.115595}, pmid = {32097807}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors ; Denitrification ; Methane ; *Methanol ; Nitrates ; Oxidation-Reduction ; }, abstract = {Nitrate removal efficiency of aerobic methane oxidation coupled with denitrification (AME-D) process was elevated by enhancing the methanol-linked synergy in a membrane biofilm reactor (MBfR) under a low O2:CH4 ratio. After 140 days' enrichment, the nitrate removal rate increased significantly from 3 to 4 mg-N L[-1] d[-1] to 22.09 ± 1.21 mg-N L[-1] d[-1] and the indicator, mol CH4 consumed/mol reduced NO3[-]-N (C/N ratio), decreased to 1.79 which was very close to the theoretical minimum value (1.27-1.39). The increased nitrate removal efficiency was largely related to the enhanced relationship between aerobic methanotrophs and methanol-utilizing denitrifiers. Type I methanotrophs and some denitrifiers, especially those potential methanol-utilizing denitrifiers from Methylobacillus, Methylotenera, Methylophilus and Methyloversatilis, were abundant in the MBfR sludge. Aerobic methanotrophs and potential methanol-utilizing denitrifiers were closely associated in many globular aggregates (5-10 μm diameter) in the MBfR sludge, which may have promoted the denitrifiers to capture methanol released by methanotrophs efficiently. If we assume methanol is the only cross-feeding intermediate in the MBfR, about 38-60% of the CH4 supplied would be converted to methanol and secreted rather than continuing to be oxidized. At least 63% of this secreted methanol should be utilized for denitrification instead of being oxidized by oxygen in the MBfR. These findings suggest that the nitrate removal efficiency of the AME-D process could be significantly improved.}, } @article {pmid32096497, year = {2020}, author = {Wang, Y and Shen, X and Ma, S and Guo, Q and Zhang, W and Cheng, L and Ding, L and Xu, Z and Jiang, J and Gao, L}, title = {Oral biofilm elimination by combining iron-based nanozymes and hydrogen peroxide-producing bacteria.}, journal = {Biomaterials science}, volume = {8}, number = {9}, pages = {2447-2458}, doi = {10.1039/c9bm01889a}, pmid = {32096497}, issn = {2047-4849}, mesh = {Biofilms/*growth & development ; Cell Survival ; Durapatite ; Ferric Compounds/*administration & dosage ; Ferrous Compounds/*administration & dosage ; Humans ; Hydrogen Peroxide/*metabolism ; Keratinocytes ; Peroxidase/*metabolism ; Saliva ; Streptococcus gordonii/*metabolism ; Streptococcus mutans/*physiology ; Tooth ; }, abstract = {Dental caries is a global risk in terms of oral health in many schoolchildren and in a vast majority of adults. The primary factor for caries formation is the attachment of bacteria on the tooth surface to form an oral biofilm which generates acids to demineralize calcium and eventually cause tooth decay. Oral biofilm elimination is still a challenge because bacteria are embedded inside with the biofilm matrix protecting them, preventing the penetration of antibiotics or bactericides. Promising strategies for disrupting oral biofilms have been developed, including the use of natural enzymes to degrade the biofilm matrix and hydrogen peroxide to kill bacteria. Here we demonstrate a strategy that combines nanozymes with peroxidase-like activity and bacteria generating biogenic hydrogen peroxide to eliminate oral biofilms for caries treatment. By using a saliva-coated hydroxyapatite disc and sectioned human tooth to mimic the real oral environment, we analyze the influence of iron oxide nanozymes or iron sulfide nanozymes on a Streptococcus mutans biofilm in the presence of Streptococcus gordonii which can generate hydrogen peroxide. Bacterial viability assays and biofilm morphology characterization show that the combination of nanozymes and bacteria remarkably reduces the bacteria number (5 lg reduction) and biofilm matrix (85% reduction). Therefore, the combination of iron-based nanozymes and hydrogen peroxide-generating bacteria may provide a new strategy for oral biofilm elimination in dental caries treatment.}, } @article {pmid32096135, year = {2020}, author = {Garcia, DR and Deckey, DG and Zega, A and Mayfield, C and Spake, CSL and Emanuel, T and Daniels, A and Jarrell, J and Glasser, J and Born, CT and Eberson, CP}, title = {Analysis of growth and biofilm formation of bacterial pathogens on frequently used spinal implant materials.}, journal = {Spine deformity}, volume = {8}, number = {3}, pages = {351-359}, doi = {10.1007/s43390-020-00054-z}, pmid = {32096135}, issn = {2212-1358}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Orthopedic Procedures ; Prostheses and Implants/*microbiology/ultrastructure ; Spine/surgery ; Staphylococcus aureus/*growth & development/physiology/ultrastructure ; Staphylococcus epidermidis/*growth & development/physiology/ultrastructure ; Surgical Wound Infection/*microbiology ; }, abstract = {STUDY DESIGN: A microscopy-based investigation of the permissive factors leading towards bacterial adherence on commonly utilized spinal implants.

OBJECTIVE: The adherence and subsequent colonization and biofilm formation of bacteria on orthopaedic implants represents one of the most serious problems facing orthopaedic surgeons. Once a biofilm is formed, surgeons may have to resort to implant removal, a strategy that may cause substantial patient morbidity and lead to additional cost to the healthcare system. This problem has been further compounded by the rise of antibiotic-resistant strains of bacterial pathogens. In this study, two commonly encountered bacterial pathogens in surgical site infections (SSI) were characterized for adherence pattern, density, and propagation on five commonly used spinal implant materials via scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results show that bacterial adherence is largely dependent on the microtopographical features observed on the surface of the materials tested.

METHODS: Five commonly utilized spinal implant materials were inoculated with two of the most common nosocomial pathogens and visualized via scanning electron microscopy and confocal laser scanning microscopy.

RESULTS: Analysis of 90 spinal implant pieces showed that even though no material showed the ability to prevent adherence of both pathogens tested, the presence of surface imperfections and rougher microtopography was found to harbor the most bacterial presence.

CONCLUSION: Our data suggests that implants materials with uniform surface and minimal imperfections may reduce the ability of bacterial to adhere to implants.

LEVEL OF EVIDENCE: Level I evidence: "Investigation of a diagnostic test".}, } @article {pmid32095864, year = {2020}, author = {Wong, LL and Natarajan, G and Boleij, M and Thi, SS and Winnerdy, FR and Mugunthan, S and Lu, Y and Lee, JM and Lin, Y and van Loosdrecht, M and Law, Y and Kjelleberg, S and Seviour, T}, title = {Extracellular protein isolation from the matrix of anammox biofilm using ionic liquid extraction.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {8}, pages = {3643-3654}, pmid = {32095864}, issn = {1432-0614}, support = {1301-IRIS-59//Ministry of the Environment and Water Resources - Singapore (SG)/ ; SCELSE//Ministry of Education - Singapore/ ; }, mesh = {Ammonium Compounds/*chemistry ; Anaerobiosis ; Bacteria/*chemistry ; Bacterial Proteins/*isolation & purification ; *Biofilms ; Bioreactors ; Ionic Liquids/*chemistry ; Liquid-Liquid Extraction/methods ; Oxidation-Reduction ; Polysaccharides, Bacterial/*chemistry ; }, abstract = {Anaerobic ammonium oxidation (anammox)-performing bacteria self-assemble into compact biofilms by expressing extracellular polymeric substances (EPS). Anammox EPS are poorly characterized, largely due to their low solubility in typical aqueous solvents. Pronase digestion achieved 19.5 ± 0.9 and 41.4 ± 1.4% (w/w) more solubilization of laboratory enriched Candidatus Brocadia sinica anammox granules than DNase and amylase, respectively. Nuclear magnetic resonance profiling of the granules confirmed proteins as dominant biopolymer within the EPS. Ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate and N,N-dimethylacetamide (EMIM-Ac/DMAc) mixture was applied to extract the major structural proteins. Further treatment by anion exchange chromatography isolated homologous serine (S)- and threonine (T)-rich proteins BROSI_A1236 and UZ01_01563, which were major components of the extracted proteins, and sequentially highly similar to putative anammox extracellular proteins KUSTD1514 and WP_070066018.1 of Ca. Kuenenia stuttgartiensis and Ca. Brocadia sapporoensis, respectively. Six monosaccharides (i.e., arabinose, xylose, rhamnose, fucose, galactose, and mannose) were enriched for BROSI_A1236 against all other major proteins. The sugars, however, contributed < 0.5% (w/w) of total granular biomass and were likely co-enriched as glycoprotein appendages. This study demonstrates that BROSI_A1236 is a major extracellular component of Ca. B. sinica anammox biofilms that is likely a common anammox extracellular polymer, and can be isolated from the matrix following ionic liquid extraction.}, } @article {pmid32094136, year = {2020}, author = {Jahanbakhsh, S and Singh, NB and Yim, J and Kebriaei, R and Smith, JR and Lev, K and Tran, TT and Rose, WE and Arias, CA and Rybak, MJ}, title = {Impact of Daptomycin Dose Exposure Alone or in Combination with β-Lactams or Rifampin against Vancomycin-Resistant Enterococci in an In Vitro Biofilm Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {5}, pages = {}, pmid = {32094136}, issn = {1098-6596}, support = {R01 AI114699/AI/NIAID NIH HHS/United States ; R21 AI143229/AI/NIAID NIH HHS/United States ; K24 AI121296/AI/NIAID NIH HHS/United States ; R01 AI148342/AI/NIAID NIH HHS/United States ; R01 AI134637/AI/NIAID NIH HHS/United States ; R21 AI109266/AI/NIAID NIH HHS/United States ; }, mesh = {Ampicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Cephalosporins/pharmacology ; Daptomycin/*pharmacology ; Drug Combinations ; Enterococcus faecium/*drug effects ; Ertapenem/pharmacology ; Humans ; Microbial Sensitivity Tests ; Rifampin/*pharmacology ; Vancomycin-Resistant Enterococci/*drug effects ; beta-Lactams/*pharmacology ; }, abstract = {Enterococcus faecium strains are commonly resistant to vancomycin and β-lactams. In addition, E. faecium often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant Enterococcus faecium (VREfm), namely, strains S447 and HOU503, in an in vitro biofilm model. HOU503 harbors common LiaS and LiaR substitutions, whereas S447 lacks mutations associated with the LiaFSR pathway. MIC results demonstrated that both strains were susceptible to DAP and resistant to CPT, AMP, ERT, and RIF. The 168-h pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor models (simulating human antibiotic exposures) were used with titanium and polyurethane coupons to evaluate the efficacy of antibiotic combinations. DAP 12 and 14 achieved bactericidal activity against S447 but lacked such effect against HOU503. Addition of ERT and RIF enhanced DAP activity, allowing DAP 8 and 10 plus ERT or RIF to produce bactericidal activity against both strains at 168 h. While DAP 8 and 10 plus CPT improved killing, they did not reach bactericidal reduction against S447. Combination of AMP, CPT, ERT, or RIF resulted in enhanced and bactericidal activity for DAP against HOU503 at 168 h. Our data provide further support for the use of combinations of DAP with AMP, ERT, CPT, and RIF in infections caused by biofilm producing VREfm. Further research involving DAP combinations against biofilm-producing enterococci is warranted.}, } @article {pmid32093422, year = {2020}, author = {Song, X and Gaascht, F and Schmidt-Dannert, C and Salomon, CE}, title = {Discovery of Antifungal and Biofilm Preventative Compounds from Mycelial Cultures of a Unique North American Hericium sp. Fungus.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {4}, pages = {}, pmid = {32093422}, issn = {1420-3049}, support = {2016 Minnesota Futures Research grant//University of Minnesota, OVPR/ ; }, mesh = {Agaricales/*chemistry/growth & development ; *Antifungal Agents/chemistry/pharmacology ; Biofilms ; Candida albicans/*growth & development ; Mycelium/*chemistry/growth & development ; }, abstract = {Edible mushrooms are an important source of nutraceuticals and for the discovery of bioactive metabolites as pharmaceuticals. In this work, the OSMAC (One Strain, Many Active Compounds) approach was used to isolate two new compounds (1 and 2) along with seven known compounds (3-9) from a mycelial culture of a unique North American edible mushroom Hericium sp. The fruiting body was collected in Marine on St. Croix, Minnesota (USA), and mycelial cultures were grown on four different solid and liquid media. Extracts from the mycelial cultures were screened for antimicrobial activity and only the extract from the Cheerios substrate culture exhibited antifungal activity. Bioassay guided fractionation and HPLC analysis were used to isolate nine pure compounds and the structures of the known compounds were established by analysis of the NMR and mass spectrometry data and comparison to published reports. Compound 1 is a new erinacerin alkaloid and 2 is an aldehyde derivative of 4-hydroxy chroman. Four chlorinated orcinol derivatives (3-6), a pyran (7), erinaceolactone (8), and erinacine (9) were identified. Compound 4 showed antifungal activity against C. albicans and C. neoformans (MIC = 31.3-62.5 μg/mL, respectively). Compound 4 also inhibited biofilm formation of C. albicans and C. neoformans at 7.8 μg/mL. These results suggest that mycelial cultures of edible fungi may provide useful, bioactive compounds.}, } @article {pmid32093365, year = {2020}, author = {Li, Y and Yang, B and Tian, J and Sun, W and Wang, G and Qian, A and Wang, C and Shan, X and Kang, Y}, title = {An iTRAQ-Based Comparative Proteomics Analysis of the Biofilm and Planktonic States of Aeromonas veronii TH0426.}, journal = {International journal of molecular sciences}, volume = {21}, number = {4}, pages = {}, pmid = {32093365}, issn = {1422-0067}, support = {JJKH20190910KJ//he 13th Five-Year Science and Technology Research and Planning Project of Education Department of Jilin province/ ; 201801//Doctoral Fund of Jilin Agricultural University/ ; 20170101016JC//the Natural Science Foundation of Science and Technology Department of Jilin Province/ ; JJKH20180694KJ//the Project of Jilin Provincial Education Department/ ; }, mesh = {Aeromonas veronii/*physiology ; Bacterial Proteins/*biosynthesis ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/*physiology ; *Proteomics ; }, abstract = {Aeromonas veronii is a virulent fish pathogen that causes extensive economic losses in the aquaculture industry worldwide. In this study, a virulent strain of A. veronii TH0426 was used to establish an in vitro biofilm model. The results show that the biofilm-forming abilities of A. veronii TH0426 were similar in different media, peaking under conditions of 20 °C and pH 6. Further, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics methods were used to compare the differential expression of A. veronii between the biofilm and planktonic cells. The results show alterations in 277 proteins, with 130 being upregulated and 147 downregulated. Pathway analysis and GO (Gene Ontology) annotations indicated that these proteins are mainly involved in metabolic pathways and the biosynthesis of secondary metabolites and antibiotics. These proteins are the main factors affecting the adaptability of A. veronii to its external environment. MRM (multiple reaction 27 monitoring) and qPCR (qPCR) were used to verify the differential proteins of the selected A. veronii. This is the first report on the biofilm and planktonic cells of A. veronii, thus contributing to studying the infection and pathogenesis of A. veronii.}, } @article {pmid32092999, year = {2020}, author = {Ogawa, A and Takakura, K and Hirai, N and Kanematsu, H and Kuroda, D and Kougo, T and Sano, K and Terada, S}, title = {Biofilm Formation Plays a Crucial Rule in the Initial Step of Carbon Steel Corrosion in Air and Water Environments.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {4}, pages = {}, pmid = {32092999}, issn = {1996-1944}, abstract = {In this study, we examined the relationship between the effect of a zinc coating on protecting carbon steel against biofilm formation in both air and water environments. SS400 carbon steel coupons were covered with a zinc thermal spray coating or copper thermal spray coating. Coated coupons were exposed to either air or water conditions. Following exposure, the surface conditions of each coupon were observed using optical microscopy, and quantitatively analyzed using an x-ray fluorescence analyzer. Debris on the surface of the coupons was used for biofilm analysis including crystal violet staining for quantification, Raman spectroscopic analysis for qualification, and microbiome analysis. The results showed that the zinc thermal spray coating significantly inhibited iron corrosion as well as biofilm formation in both air and water environments. The copper thermal spray coating, however, accelerated iron corrosion in both air and water environments, but accelerated biofilm formation only in a water environment. microbially-influenced-corrosion-related bacteria were barely detected on any coupons, whereas biofilms were detected on all coupons. To summarize these results, electrochemical corrosion is dominant in an air environment and microbially influenced corrosion is strongly involved in water corrosion. Additionally, biofilm formation plays a crucial rule in carbon steel corrosion in both air and water, even though microbially-influenced-corrosion-related bacteria are barely involved in this corrosion.}, } @article {pmid32090355, year = {2020}, author = {Chen, G and Gan, J and Yang, C and Zuo, Y and Peng, J and Li, M and Huo, W and Xie, Y and Zhang, Y and Wang, T and Deng, X and Liang, H}, title = {The SiaA/B/C/D signaling network regulates biofilm formation in Pseudomonas aeruginosa.}, journal = {The EMBO journal}, volume = {39}, number = {6}, pages = {e103412}, pmid = {32090355}, issn = {1460-2075}, support = {2019JQ-134//Natural Science Basic Research Program of Shaanxi/International ; IRT1174//The Program for Changjiang Scholars and Innovative Research Team in University/International ; ITR_15R55//The Program for Changjiang Scholars and Innovative Research Team in University/International ; 31622003//National Natural Science Foundation of China/International ; 31670080//National Natural Science Foundation of China/International ; 31870060//National Natural Science Foundation of China/International ; 31700064//National Natural Science Foundation of China/International ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Phenotype ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; Pseudomonas aeruginosa/enzymology/genetics/pathogenicity/*physiology ; *Signal Transduction ; Virulence ; }, abstract = {Bacterial cyclic-di-GMP (c-di-GMP) production is associated with biofilm development and the switch from acute to chronic infections. In Pseudomonas aeruginosa, the diguanylate cyclase (DGC) SiaD and phosphatase SiaA, which are co-transcribed as part of a siaABCD operon, are essential for cellular aggregation. However, the detailed functions of this operon and the relationships among its constituent genes are unknown. Here, we demonstrate that the siaABCD operon encodes for a signaling network that regulates SiaD enzymatic activity to control biofilm and aggregates formation. Through protein-protein interaction, SiaC promotes SiaD diguanylate cyclase activity. Biochemical and structural data revealed that SiaB is an unusual protein kinase that phosphorylates SiaC, whereas SiaA phosphatase can dephosphorylate SiaC. The phosphorylation state of SiaC is critical for its interaction with SiaD, which will switch on or off the DGC activity of SiaD and regulate c-di-GMP levels and subsequent virulence phenotypes. Collectively, our data provide insights into the molecular mechanisms underlying the modulation of DGC activity associated with chronic infections, which may facilitate the development of antimicrobial drugs.}, } @article {pmid32089678, year = {2020}, author = {Eladawy, M and El-Mowafy, M and El-Sokkary, MMA and Barwa, R}, title = {Effects of Lysozyme, Proteinase K, and Cephalosporins on Biofilm Formation by Clinical Isolates of Pseudomonas aeruginosa.}, journal = {Interdisciplinary perspectives on infectious diseases}, volume = {2020}, number = {}, pages = {6156720}, pmid = {32089678}, issn = {1687-708X}, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that can form biofilms, which confer resistance to immune clearance and antibacterial treatment. Therefore, effective strategies to prevent biofilm formation are warranted. Here, 103 P. aeruginosa clinical isolates were quantitatively screened for biofilm formation ability via the tissue culture plate method. The effects of lysozyme (hydrolytic enzyme) and proteinase K (protease) on biofilm formation were evaluated at different concentrations. Lysozyme (30 μg/mL), but not proteinase K, significantly inhibited biofilm formation (19% inhibition). Treatment of 24-hour-old biofilms of P. aeruginosa isolates with 50 times the minimum inhibitory concentrations (MICs) of ceftazidime and cefepime significantly decreased the biofilm mass by 32.8% and 44%, respectively. Moreover, the exposure of 24-hour-old biofilms of P. aeruginosa isolates to lysozyme (30 μg/mL) and 50 times MICs of ceftazidime or cefepime resulted in a significant reduction in biofilm mass as compared with the exposure to lysozyme or either antibacterial agent alone. The best antibiofilm effect (49.3%) was observed with the combination of lysozyme (30 μg/mL) and 50 times MIC of cefepime. The promising antibiofilm activity observed after treatment with 50 times MIC of ceftazidime or cefepime alone or in combination with lysozyme (30 μg/mL) is indicative of a novel strategy to eradicate pseudomonal biofilms in intravascular devices and contact lenses.}, } @article {pmid32089579, year = {2020}, author = {Dwivedi, M and Muralidhar, S and Saluja, D}, title = {Hibiscus sabdariffa Extract Inhibits Adhesion, Biofilm Initiation and Formation in Candida albicans.}, journal = {Indian journal of microbiology}, volume = {60}, number = {1}, pages = {96-106}, pmid = {32089579}, issn = {0046-8991}, support = {P40 OD010440/OD/NIH HHS/United States ; }, abstract = {Microbial biofilms act as reservoirs for pathogenic sessile microbes which reside inside the three dimensional matrix of the biofilm, and are thus protected against anti-microbial drugs. Most of the anti-microbial drugs fail to completely abolish the biofilm associated infections. In the present study, we provide evidence of Hibiscus sabdariffa (Hs) extract having possible anti-microbial activity, with emphasis on Candida albicans biofilm. The Hs extract was shown to be effective against C. albicans pre-formed biofilm at 3.125 mg/ml and was able to inhibit the hyphae initiation and adherence of cells. Furthermore, Hs extract was able to reduce the C. albicans load in C. elegans by effectively killing the Candida cells thereby reducing the viable colony count and effectively increasing the lifespan of worms. The percentage of viable hatched progeny of worms exposed to Hs extract (both at conc. 1.5 mg/ml and 6.25 mg/ml), was also comparable to that of the control untreated eggs. The Hs extract was also found to be significantly effective against fluconazole resistant C. albicans isolated from patients. Thus, we, for the first time, propose Hs extract as a prospective drug candidate and substitute for eradicating pre-formed biofilm and inhibiting the growth of C. albicans.}, } @article {pmid32089576, year = {2020}, author = {Meena, H and Mishra, R and Ranganathan, S and Sarma, VV and Ampasala, DR and Kalia, VC and Lee, JK and Siddhardha, B}, title = {Phomopsis tersa as Inhibitor of Quorum Sensing System and Biofilm Forming Ability of Pseudomonas aeruginosa.}, journal = {Indian journal of microbiology}, volume = {60}, number = {1}, pages = {70-77}, pmid = {32089576}, issn = {0046-8991}, abstract = {Endophytic fungi provide rich reservoir for novel antimicrobial compounds. An endophytic fungus, from Carica papaya plant identified as Phomopsis tersa, was investigated for attenuating the quorum sensing mediated pathogenicity of Pseudomonas aeruginosa PAO1. Crude extract of P. tersa was found to reduce the production of redox-active pigments-pyocyanin and pyoverdine in P. aeruginosa PAO1 by 92.46% and 71.55%, respectively at sub-MIC concentration of 900 μg/mL. In addition, the crude extract was also able to inhibit the expression of virulence factors involved in biofilm formation: exopolysaccharide (72.21%) and alginate (72.50%). Secretion of cell-lytic enzymes was also found to be reduced: chitinase by 79.73% and elastase by 74.30%. 3-Isobutylhexahydropyrrolo[1,2-a]pyrazine-1,4-dione identified from GC-MS analysis, displayed favorable molecular interactions with P. aeruginosa transcriptional regulators, LasR and RhlR with good docking scores of - 6.873 kJ/mol and - 6.257 kJ/mol, respectively. The study thus reveals the potential use of P. tersa for discovering drugs against infectious pathogens.}, } @article {pmid32087316, year = {2020}, author = {Shehabeldine, AM and Ashour, RM and Okba, MM and Saber, FR}, title = {Callistemon citrinus bioactive metabolites as new inhibitors of methicillin-resistant Staphylococcus aureus biofilm formation.}, journal = {Journal of ethnopharmacology}, volume = {254}, number = {}, pages = {112669}, doi = {10.1016/j.jep.2020.112669}, pmid = {32087316}, issn = {1872-7573}, mesh = {Biofilms/*drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects/ultrastructure ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning Transmission ; Myrtaceae/*chemistry ; Phytochemicals/isolation & purification/pharmacology ; Plant Extracts/chemistry/*pharmacology ; Plant Leaves/chemistry ; Staphylococcus aureus/*drug effects/ultrastructure ; Xanthophylls/*antagonists & inhibitors ; }, abstract = {The development of new inhibitors of bacterial virulence factors from natural origin has recently received significant attention. Callistemon citrinus Skeels is an important plant of great medicinal value. Its antimicrobial activity is well documented. Although several compounds were isolated from this plant, the actual bioactive compounds responsible for its antimicrobial activity are still unrevealed.

AIM OF THE STUDY: To evaluate the effect of C. citrinus crude extract and isolated compounds on methicillin-resistant and sensitive Staphylococcus aureus.

MATERIALS AND METHODS: The methylene chloride-methanol extract (MME) of C. citrinus leaves was prepared by Soxhlet apparatus. Biologically guided fractionation of MME was accomplished using several normal and reversed phase silica gel columns. The potency of MME and its isolated compounds against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) was evaluated. In addition, the mechanism of resistance was studied using three virulence factors; antibiofilm activity, inhibition of staphyloxanthin biosynthesis and effect on acid tolerance. Ultrastructural changes in MRSA and MSSA were observed by TEM to understand mode of action of these compounds.

RESULTS: Pulverulentone A (C1), 8- desmethyl eucalyptin (C2) and eucalyptin (C3) were isolated from the most bioactive fraction of MME. Confocal scanning laser microscopy images revealed that C. citrinus isolated compounds destroyed the intact architecture of biofilm, thickness and reduced its biomass. Pulverulentone A (C1) showed the most potent anti-biofilm activity up to 71% and 62.3% against MRSA and MSSA, respectively. It also exhibited the highest inhibition of staphyloxanthin biosynthesis of MRSA and MSSA by 55.6% and 54.5%, respectively. The bacterial cell membrane was compromised, losing its integrity and releasing important cellular constituents when exposed to C1-C3 CONCLUSIONS: C. citrinus phenolics and acylphloroglucinols may serve as potential source of plant-based antibacterials and thus could be implicated to control MRSA biofilm formation.}, } @article {pmid32086747, year = {2020}, author = {Ahmed, T and Pattnaik, S and Khan, MB and Ampasala, DR and Busi, S and Sarma, VV}, title = {Inhibition of quorum sensing-associated virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1 by Mycoleptodiscus indicus PUTY1.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {2}, pages = {467-487}, pmid = {32086747}, issn = {1678-4405}, mesh = {Ascomycota/*chemistry ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Molecular Dynamics Simulation ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/*drug effects ; Secondary Metabolism ; Virulence Factors/*antagonists & inhibitors ; }, abstract = {Pseudomonas aeruginosa is the second most emerging multidrug-resistant, opportunistic pathogen after Acinetobacter baumannii that poses a threat in nursing homes, hospitals, and patients who need devices such as ventilators and blood catheters. Its ability to form quorum sensing-regulated virulence factors and biofilm makes it more resistant to top most therapeutic agents such as carbapenems and next-generation antibiotics. In the current study, we studied the quorum quenching potential of secondary metabolites of Mycoleptodiscus indicus PUTY1 strain. In vitro observation showed a mitigation in virulence factors such as rhamnolipids, protease, elastase pyocyanin, exopolysaccharides, and hydrogen cyanide gas. Furthermore, a significant reduction in the motility such as swimming, swarming, twitching, and inhibition in biofilm formation by Pseudomonas aeruginosa PAO1 was observed. Results of in vitro studies were further confirmed by in silico studies through docking and molecular dynamic simulation of GC-MS-detected compounds of Mycoleptodiscus indicus employing LasR and RhlR proteins. Both in vitro and in silico observations indicate a new alternative approach for combating virulence of Pseudomonas aeruginosa by targeting its protein receptors LasR and RhlR. Graphical abstract.}, } @article {pmid32086003, year = {2020}, author = {Zhai, S and Ji, M and Zhao, Y and Su, X}, title = {Shift of bacterial community and denitrification functional genes in biofilm electrode reactor in response to high salinity.}, journal = {Environmental research}, volume = {184}, number = {}, pages = {109007}, doi = {10.1016/j.envres.2019.109007}, pmid = {32086003}, issn = {1096-0953}, mesh = {Betaproteobacteria ; *Biofilms ; *Bioreactors ; *Denitrification ; Electrodes ; Nitrates ; Nitrogen ; Piscirickettsiaceae ; Salinity ; }, abstract = {High salinity suppresses denitrification by inhibiting microorganism activities. The shift of microbial community and denitrification functional genes under salinity gradient was systematically investigated in a biofilm electrode reactor (BER) and biofilm reactor (BR) systems. Denitrification efficiency of both BER and BR was not significantly inhibited during the period of low salinity (0-2.0%). As the salinity increased to 2.5%, BER could overcome the impact of high salinity and maintained a relatively stable denitrification performance, and the effluent NO3[-]-N was lower than 1.5 mg/L. High salinity (>2.5%) impoverished microbial diversity and altered the microbial community in both BER and BR. However, two genera Methylophaga and Methyloexplanations were enriched in BER due to electrochemical stimulation, which can tolerate high salinity (>3.0%). The relative abundance of Methylophaga in BER was almost 10 times as much as in BR. Paracoccus is a hydrogen autotrophic denitrifier, which was obviously inhibited with 1.0% NaCl. The hetertrophic denitrifiers were primarily responsible for the nitrate removal in the BER compared to the autotrophic denitrifiers. The abundance and proportion of denitrifying functional genes confirmed that main denitrifiers shift to salt-tolerant species (nirK-type denitrifiers) to reduce the toxic effects. The napA (2.2 × 10[8] to 6.5 × 10[8] copies/g biofilm) and nosZ (2.2 × 10[7] to 4.4 × 10[7] copies/g biofilm) genes were more abundant in BER compared to BR's, which was attributed to the enrichment of Methylophaga alcalica and Methyloversatilis universalis FAM5 in the BER. The results proved that BER had greater denitrification potential under high salinity (>2.0%) stress at the molecular level.}, } @article {pmid32085686, year = {2021}, author = {Cui, F and Kim, M and Lee, W and Park, C and Kim, M}, title = {Pseudo-analytical solutions for multi-species biofilm model of aerobic granular sludge.}, journal = {Environmental technology}, volume = {42}, number = {22}, pages = {3421-3431}, doi = {10.1080/09593330.2020.1733673}, pmid = {32085686}, issn = {1479-487X}, mesh = {Aerobiosis ; Biofilms ; Bioreactors ; Nitrogen ; *Sewage ; *Waste Disposal, Fluid ; }, abstract = {This paper demonstrates modelling of the aerobic granular sludge (AGS) process with the pseudo-analytical solutions (PAS) of a biofilm model. A MATLAB programmed graphical user interface platform was developed to facilitate the model calculation and access. Model calibration and validation were carried out through using experimental data collected from a granular sludge sequencing batch reactor operation. The experimental and modelling results identified the distribution of heterotrophs and nitrifiers on the AGS and its contribution to the performance of wastewater treatment. The model could describe multi-species biofilms according to the distinguishing features among the three levels of PAS models. The models demonstrated increasing degrees of interaction (no interaction, competition for nitrogen and layering and protection) between heterotrophs and nitrifiers. Modelling the AGS process using PAS increases the accessibility of the simulation of multiple species in both biofilm and suspended biomass.}, } @article {pmid32084407, year = {2020}, author = {Lories, B and Roberfroid, S and Dieltjens, L and De Coster, D and Foster, KR and Steenackers, HP}, title = {Biofilm Bacteria Use Stress Responses to Detect and Respond to Competitors.}, journal = {Current biology : CB}, volume = {30}, number = {7}, pages = {1231-1244.e4}, pmid = {32084407}, issn = {1879-0445}, support = {209397/Z/17/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*Biofilms ; Drug Resistance, Bacterial/*genetics ; Genome, Bacterial/*physiology ; Microbial Interactions/*genetics ; Phenotype ; Salmonella typhimurium/*physiology ; Single-Cell Analysis ; }, abstract = {Bacteria use complex regulatory networks to cope with stress, but the function of these networks in natural habitats is poorly understood. The competition sensing hypothesis states that bacterial stress response systems can serve to detect ecological competition, but studying regulatory responses in diverse communities is challenging. Here, we solve this problem by using differential fluorescence induction to screen the Salmonella Typhimurium genome for loci that respond, at the single-cell level, to life in biofilms with competing strains of S. Typhimurium and Escherichia coli. This screening reveals the presence of competing strains drives up the expression of genes associated with biofilm matrix production (CsgD pathway), epithelial invasion (SPI1 invasion system), and, finally, chemical efflux and antibiotic tolerance (TolC efflux pump and AadA aminoglycoside 3-adenyltransferase). We validate that these regulatory changes result in the predicted phenotypic changes in biofilm, mammalian cell invasion, and antibiotic tolerance. We further show that these responses arise via activation of major stress responses, providing direct support for the competition sensing hypothesis. Moreover, inactivation of the type VI secretion system (T6SS) of a competitor annuls the responses to competition, indicating that T6SS-derived cell damage activates these stress response systems. Our work shows that bacteria use stress responses to detect and respond to competition in a manner important for major phenotypes, including biofilm formation, virulence, and antibiotic tolerance.}, } @article {pmid32084213, year = {2020}, author = {Jalal, N and Lee, SF}, title = {The MsrAB reducing pathway of Streptococcus gordonii is needed for oxidative stress tolerance, biofilm formation, and oral colonization in mice.}, journal = {PloS one}, volume = {15}, number = {2}, pages = {e0229375}, pmid = {32084213}, issn = {1932-6203}, mesh = {Amino Acid Sequence ; Animals ; Bacterial Proteins ; Biofilms/*growth & development ; Female ; Gene Expression Regulation, Bacterial ; Membrane Transport Proteins ; Methionine Sulfoxide Reductases/*metabolism ; Mice ; Mice, Inbred BALB C ; Mouth/*microbiology ; *Operon ; *Oxidative Stress ; Sequence Homology ; Signal Transduction ; Streptococcal Infections/*microbiology/pathology ; Streptococcus gordonii/enzymology/*growth & development ; }, abstract = {The ability of Streptococcus gordonii to cope with oxidative stress is important for survival and persistence in dental plaque. In this study, we used mutational, phenotypic, and biochemical approaches to characterize the role of a methionine sulfoxide reductase (MsrAB) and proteins encoded by genes in the msrAB operon and an adjacent operon in oxidative stress tolerance in S. gordonii. The results showed that MsrAB and four other proteins encoded in the operons are needed for protection from H2O2 and methionine sulfoxide. These five proteins formed a reducing pathway that was needed for oxidative stress tolerance, biofilm formation, and oral colonization in mice. In the pathway, MsrAB was the enzyme that repaired oxidatively damaged proteins, and the two thioredoxin-like lipoproteins (SdbB and Sgo_1177) and two CcdA proteins were proteins that maintained the catalytic cycle of MsrAB. Consistent with the role in oxidative stress tolerance, the production of MsrAB, SdbB, and Sgo_11777 was induced in aerobic growth and planktonic cells.}, } @article {pmid32084198, year = {2020}, author = {Kirchhoff, L and Arweiler-Harbeck, D and Arnolds, J and Hussain, T and Hansen, S and Bertram, R and Buer, J and Lang, S and Steinmann, J and Höing, B}, title = {Imaging studies of bacterial biofilms on cochlear implants-Bioactive glass (BAG) inhibits mature biofilm.}, journal = {PloS one}, volume = {15}, number = {2}, pages = {e0229198}, pmid = {32084198}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects/ultrastructure ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects/growth & development ; Cochlear Implants/*microbiology ; *Glass ; *Microscopy, Electron, Scanning ; *Molecular Imaging ; }, abstract = {The capability of Pseudomonas aeruginosa and Staphylococcus aureus to form biofilm on varying CI component materials differs in the presence and absence of bioactive glass (BAG). The application of BAG induces significant changes in biofilm morphology which can be visualized via scanning electron microscopy (SEM). Bacterial biofilm formation on medical devices, such as cochlear implants (CI), can lead to chronic infections. Interestingly, BAG of type S53P4 seems to be a promising tool for use in the reduction of biofilm development. Primarily, four bacterial species known to cause implant-related infections, P.aeruginosa (ATCC9027), S. aureus (ATCC6538), Staphylococcus epidermidis (ATCC12228) and Streptococcus pyogenes (ATCC19615) were analyzed regarding their capacity to form biofilm on CI components manufactured from three kinds of material: silicone, platinum and titanium. Subsequently, P. aeruginosa and S. aureus biofilms were visualized using scanning electron microscopy, comparing BAG-treated biofilm with non-treated biofilm. The four bacterial species presented biofilm-forming capabilities in a species and surface dependent manner. Metal CI components allowed for the greatest proliferation of biofilm. S. aureus and P. aeruginosa showed the highest rate of biofilm formation on polystyrene surfaces. For both species, SEM revealed altered biofilm morphology after treatment of S53P4 BAG. This study indicates that bacterial biofilm formation and structure on CI components is dependent on the surface composition, altering between metal and silicone surfaces. After application of BAG, changes in biofilm morphology on CI components were observed. These data highlight the impact of BAG on bacterial biofilm morphology.}, } @article {pmid32083796, year = {2020}, author = {Budell, WC and Germain, GA and Janisch, N and McKie-Krisberg, Z and Jayaprakash, AD and Resnick, AE and Quadri, LEN}, title = {Transposon mutagenesis in Mycobacterium kansasii links a small RNA gene to colony morphology and biofilm formation and identifies 9,885 intragenic insertions that do not compromise colony outgrowth.}, journal = {MicrobiologyOpen}, volume = {9}, number = {4}, pages = {e988}, pmid = {32083796}, issn = {2045-8827}, support = {R03 AI128314/AI/NIAID NIH HHS/United States ; R03 AI135755/AI/NIAID NIH HHS/United States ; R03 AI 128314/NH/NIH HHS/United States ; R03 AI 135755/NH/NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Butterflies/microbiology ; DNA Transposable Elements/*genetics ; Genome, Bacterial/genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Mutagenesis/genetics ; Mycobacterium Infections, Nontuberculous/*drug therapy/microbiology ; Mycobacterium kansasii/*drug effects/*genetics/growth & development ; Opportunistic Infections/drug therapy/microbiology ; RNA, Bacterial/*genetics ; }, abstract = {Mycobacterium kansasii (Mk) is a resilient opportunistic human pathogen that causes tuberculosis-like chronic pulmonary disease and mortality stemming from comorbidities and treatment failure. The standard treatment of Mk infections requires costly, long-term, multidrug courses with adverse side effects. The emergence of drug-resistant isolates further complicates the already challenging drug therapy regimens and threatens to compromise the future control of Mk infections. Despite the increasingly recognized global burden of Mk infections, the biology of this opportunistic pathogen remains essentially unexplored. In particular, studies reporting gene function or generation of defined mutants are scarce. Moreover, no transposon (Tn) mutagenesis tool has been validated for use in Mk, a situation limiting the repertoire of genetic approaches available to accelerate the dissection of gene function and the generation of gene knockout mutants in this poorly characterized pathogen. In this study, we validated the functionality of a powerful Tn mutagenesis tool in Mk and used this tool in conjunction with a forward genetic screen to establish a previously unrecognized role of a conserved mycobacterial small RNA gene of unknown function in colony morphology features and biofilm formation. We also combined Tn mutagenesis with next-generation sequencing to identify 12,071 Tn insertions that do not compromise viability in vitro. Finally, we demonstrated the susceptibility of the Galleria mellonella larva to Mk, setting the stage for further exploration of this simple and economical infection model system to the study of this pathogen.}, } @article {pmid32083136, year = {2020}, author = {Li, X and Kim, J and Wu, J and Ahamed, AI and Wang, Y and Martins-Green, M}, title = {N-Acetyl-cysteine and Mechanisms Involved in Resolution of Chronic Wound Biofilm.}, journal = {Journal of diabetes research}, volume = {2020}, number = {}, pages = {9589507}, pmid = {32083136}, issn = {2314-6753}, support = {R21 AI138188/AI/NIAID NIH HHS/United States ; }, mesh = {Acetylcysteine/*pharmacology ; Animals ; Biofilms/*drug effects ; Chronic Disease ; DNA, Bacterial/analysis/drug effects ; *Diabetes Mellitus ; Disease Models, Animal ; Extracellular Polymeric Substance Matrix/*drug effects ; Free Radical Scavengers/*pharmacology ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Mice ; Mice, Obese ; Microbial Viability/drug effects ; Microscopy, Confocal ; Microscopy, Fluorescence ; Oxidative Stress/drug effects ; Protein Biosynthesis/drug effects ; *Pseudomonas Infections ; Pseudomonas aeruginosa/*drug effects/metabolism/ultrastructure ; *Wound Infection ; Wounds and Injuries ; }, abstract = {Chronic wounds are a major global health problem with the presence of biofilm significantly contributing to wound chronicity. Current treatments are ineffective in resolving biofilm and simultaneously killing the bacteria; therefore, effective biofilm-resolving drugs are needed. We have previously shown that, together with α-tocopherol, N-acetyl-cysteine (NAC) significantly improves the healing of biofilm-containing chronic wounds, in a diabetic mouse model we developed, by causing disappearance of the bacteria and breakdown of the extracellular polymeric substance (EPS). We hypothesize that NAC creates a microenvironment that affects bacterial survival and EPS integrity. To test this hypothesis, we developed an in vitro biofilm system using microbiome taken directly from diabetic mouse chronic wounds. For these studies, we chose mice in which chronic wound microbiome was rich in Pseudomonas aeruginosa (97%). We show that NAC at concentrations with pH < pKa causes bacterial cell death and breakdown of EPS. When used before biofilm is formed, NAC leads to bacterial cell death whereas treatment after the biofilm is established NAC causes biofilm dismantling accompanied by bacterial cell death. Mechanistically, we show that NAC can penetrate the bacterial membrane, increase oxidative stress, and halt protein synthesis. We also show that low pH is important for the actions of NAC and that bacterial death occurs independently of the presence of biofilm. In addition, we show that both the acetyl and carboxylic groups play key roles in NAC functions. The results presented here provide insight into the mechanisms by which NAC dismantles biofilm and how it could be used to treat chronic wounds after debridement (NAC applied at the start of culture) or without debridement (NAC applied when biofilm is already formed). This approach can be taken to develop biofilm from microbiome taken directly from human chronic wounds to test molecules that could be effective for the treatment of specific biofilm compositions.}, } @article {pmid32082279, year = {2020}, author = {Martín-Rodríguez, AJ and Rhen, M and Melican, K and Richter-Dahlfors, A}, title = {Nitrate Metabolism Modulates Biosynthesis of Biofilm Components in Uropathogenic Escherichia coli and Acts as a Fitness Factor During Experimental Urinary Tract Infection.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {26}, pmid = {32082279}, issn = {1664-302X}, abstract = {To successfully colonize a variety of environments, bacteria can coordinate complex collective behaviors such as biofilm formation. To thrive in oxygen limited niches, bacteria's versatile physiology enables the utilization of alternative electron acceptors. Nitrate, the second most favorable electron acceptor after oxygen, plays a prominent role in the physiology of uropathogenic Escherichia coli (UPEC) and is abundantly found in urine. Here we analyzed the role of extracellular nitrate in the pathogenesis of the UPEC strain CFT073 with an initial focus on biofilm formation. Colony morphotyping in combination with extensive mutational, transcriptional, and protein expression analyses of CFT073 wild-type and mutants deficient in one or several nitrate reductases revealed an association between nitrate reduction and the biosynthesis of biofilm extracellular matrix components. We identified a role for the nitrate response regulator NarL in modulating expression of the biofilm master regulator CsgD. To analyze the role of nitrate reduction during infection in vivo, we tested wild-type CFT073 and a nitrate reductase null mutant in an ascending urinary tract infection (UTI) model. Individually, each strain colonized extensively, suggesting that nitrate reduction is expendable during UTI. However, during competitive co-infection, the strain incapable of nitrate reduction was strongly outcompeted. This suggests that nitrate reduction can be considered a non-essential but advantageous fitness factor for UPEC pathogenesis. This implies that UPEC rapidly adapts their metabolic needs to the microenvironment of infected tissue. Collectively, this work demonstrates a unique association between nitrate respiration, biofilm formation, and UPEC pathogenicity, highlighting how the use of alternative electron acceptors enables bacterial pathogens to adapt to challenging infectious microenvironments.}, } @article {pmid32081907, year = {2020}, author = {Tursi, SA and Puligedda, RD and Szabo, P and Nicastro, LK and Miller, AL and Qiu, C and Gallucci, S and Relkin, NR and Buttaro, BA and Dessain, SK and Tükel, Ç}, title = {Salmonella Typhimurium biofilm disruption by a human antibody that binds a pan-amyloid epitope on curli.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {1007}, pmid = {32081907}, issn = {2041-1723}, support = {R21 AI119368/AI/NIAID NIH HHS/United States ; R21 AI137541/AI/NIAID NIH HHS/United States ; R21 AI132996/AI/NIAID NIH HHS/United States ; R56 AI125429/AI/NIAID NIH HHS/United States ; U01 AG010483/AG/NIA NIH HHS/United States ; R21 AI126133/AI/NIAID NIH HHS/United States ; }, mesh = {Amyloid/*immunology ; Animals ; Antibodies, Monoclonal/immunology ; Bacterial Proteins/*immunology ; Biofilms/*growth & development ; Catheter-Related Infections/prevention & control ; Epitopes/immunology ; Humans ; Macrophages/immunology ; Mice ; Salmonella Infections/prevention & control ; Salmonella typhimurium/*immunology/*physiology ; }, abstract = {Bacterial biofilms, especially those associated with implanted medical devices, are difficult to eradicate. Curli amyloid fibers are important components of the biofilms formed by the Enterobacteriaceae family. Here, we show that a human monoclonal antibody with pan-amyloid-binding activity (mAb 3H3) can disrupt biofilms formed by Salmonella enterica serovar Typhimurium in vitro and in vivo. The antibody disrupts the biofilm structure, enhancing biofilm eradication by antibiotics and immune cells. In mice, 3H3 injections allow antibiotic-mediated clearance of catheter-associated S. Typhimurium biofilms. Thus, monoclonal antibodies that bind a pan-amyloid epitope have potential to prevent or eradicate bacterial biofilms.}, } @article {pmid32077490, year = {2020}, author = {Islam, M and Durie, I and Ramadan, R and Purchase, D and Marvasi, M}, title = {Exploitation of nitric oxide donors to control bacterial adhesion on ready-to-eat vegetables and dispersal of pathogenic biofilm from polypropylene.}, journal = {Journal of the science of food and agriculture}, volume = {100}, number = {7}, pages = {3078-3086}, doi = {10.1002/jsfa.10340}, pmid = {32077490}, issn = {1097-0010}, mesh = {Bacterial Adhesion/*drug effects ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Coriandrum/microbiology ; Disinfectants/pharmacology ; Fast Foods/analysis/*microbiology ; Hydrazines/pharmacology ; Molsidomine/pharmacology ; Nitric Oxide Donors/*pharmacology ; Peas/microbiology ; Plastics/analysis ; Polypropylenes/analysis ; Salmonella typhimurium/*drug effects/physiology ; Vegetables/*microbiology ; }, abstract = {BACKGROUND: Nitric oxide (NO) donors have been used to control biofilm formation. Nitric oxide can be delivered in situ using organic carriers and acts as a signaling molecule. Cells exposed to NO shift from biofilm to the planktonic state and are better exposed to the action of disinfectants. In this study, we investigate the capability of the NO donors molsidomine, MAHAMA NONOate, NO-aspirin and diethylamine NONOate to act as anti-adhesion agents on ready-to-eat vegetables, as well as dispersants for a number of pathogenic biofilms on plastic.

RESULTS: Our results showed that 10 pM molsidomine reduced the attachment of Salmonella enterica sv Typhimurium 14 028 to pea shoots and coriander leaves of about 0.5 Log(CFU/leaf) when compared with untreated control. The association of 10 pmol L[-1] molsidomine with 0.006% H2 O2 showed a synergistic effect, leading to a significant reduction in cell collection on the surface of the vegetable of about 1 Log(CFU/leaf). Similar results were obtained for MAHMA NONOate. We also showed that the association of diethylamine NONOate at 10 mmol L[-1] and 10 pmol L[-1] with the quaternary ammonium compound diquat bromide improved the effectiveness of biofilm dispersal by 50% when compared with the donor alone.

CONCLUSIONS: Our findings reveal a dual role of NO compounds in biofilm control. Molsidomine, MAHMA NONOate, and diethylamine NONOate are good candidates for either preventing biofilm formation or dispersing biofilm, especially when used in conjunction with disinfectants. Nitric oxide compounds have the potential to be developed into a toolkit for pro-active practices for good agricultural practices (GAPs), hazard analysis and critical control points (HACCP), and cleaning-in-place (CIP) protocols in industrial settings where washing is routinely applied. © 2020 Society of Chemical Industry.}, } @article {pmid32077074, year = {2020}, author = {Reginatto, P and Bergamo, VZ and Berlitz, SJ and Guerreiro, ICK and de Andrade, SF and Fuentefria, AM}, title = {Rational selection of antifungal drugs to propose a new formulation strategy to control Candida biofilm formation on venous catheters.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {3}, pages = {1037-1049}, pmid = {32077074}, issn = {1678-4405}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects ; Candidiasis/microbiology/prevention & control ; Catheter-Related Infections/microbiology/prevention & control ; Central Venous Catheters/*microbiology ; Drug Combinations ; Drug Synergism ; }, abstract = {INTRODUCTION: Infections associated with medical devices are often related to colonization by Candida spp. biofilm; in this way, numerous strategies have been developed and studied, mainly in order to prevent this type of fungal growth.

AIM: Considering the above, the main objective of the present study is to make a rational choice of the best antifungal therapy for the in vitro treatment of the biofilm on venous catheters, proposing an innovative formulation of a film-forming system to coat the surface in order to prevent the formation of biofilms.

METHODOLOGY: Anidulafungin, fluconazole, voriconazole, ketoconazole, amphotericin B, and the association of anidulafungin and amphotericin B were tested against biofilms of C. albicans, C. tropicalis, and C. parapsilosis strains in microtiter plates and in a polyurethane catheter. Besides, anidulafungin, amphotericin B, and the combination of both were incorporated in a film-forming system and were evaluated against biofilm.

RESULTS: The superior activity of anidulafungin was demonstrated in relation to the other antifungal agents. Although amphotericin B showed good activity, high concentrations were required. The combination showed a synergistic action, in solution and in the formulation, showing excellent results, with activity above 90%.

CONCLUSION: Due to the superiority of anidulafungin and the synergistic activity of the combination, these alternatives were the most promising options for use in a formulation proposal as a new strategy to combat the Candida spp. biofilm. These formulations demonstrated high in vitro performance in the prevention of biofilms, indicating that they are candidates with great potential for in vivo tests.}, } @article {pmid32076613, year = {2020}, author = {Feldman, M and Sionov, R and Smoum, R and Mechoulam, R and Ginsburg, I and Steinberg, D}, title = {Comparative Evaluation of Combinatory Interaction between Endocannabinoid System Compounds and Poly-L-lysine against Streptococcus mutans Growth and Biofilm Formation.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {7258380}, pmid = {32076613}, issn = {2314-6141}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Arachidonic Acids/pharmacology ; Biofilms/*drug effects ; Dental Plaque/prevention & control ; Drug Combinations ; Endocannabinoids/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Oleic Acids/pharmacology ; Polylysine/chemistry/*pharmacology ; Polyunsaturated Alkamides/pharmacology ; Streptococcus mutans/*drug effects/growth & development ; }, abstract = {Endocannabinoid/endocannabinoid-like (EC/EC-like) are natural endogenous compounds which have been found to affect MRSA pathogenicity. Our previous studies showed that EC/EC-like was able to impair staphylococcal biofilm formation and maintenance as well as to alter biofilm-associated virulence factors. In the present study, we investigated the combinatory effect of the selected EC/EC-like with a natural antimicrobial agent, poly-L-lysine, on cariogenic bacteria Streptococcus mutans growth and biofilm formation. Among four tested EC/EC-like, only two, anandamide (AEA) and oleoylethanolamide (OEA), exhibited synergistic combinatory effect with poly-L-lysine against S. mutans. We attribute this distinct effect to differences in the fatty acid chain structure of the selected EC/EC-like compounds. Moreover, AEA exerted a specific antibiofilm mode of action against S. mutans by effecting total inhibition of biofilm formation while still allowing bacteria viability. Finally, we postulate that the presence of EC/EC-like and poly-L-lysine could enhance the permeability and efficacy of each other via hydrophobic and electrostatic interactions with the S. mutans membrane. In conclusion, we assume that a combination of endogenous natural compounds such as EC/EC-like and poly-L-lysine may benefit oral hygiene by preventing dental plaque.}, } @article {pmid32074168, year = {2021}, author = {Shafiei, SNS and Ahmad, K and Ikhsan, NFM and Ismail, SI and Sijam, K}, title = {Suppression of Xanthomonas oryzae pv. oryzae biofilm formation by Acacia mangium methanol leaf extract.}, journal = {Brazilian journal of biology = Revista brasleira de biologia}, volume = {81}, number = {1}, pages = {11-17}, doi = {10.1590/1519-6984.206124}, pmid = {32074168}, issn = {1678-4375}, mesh = {*Acacia ; Biofilms ; Methanol ; *Oryza ; Plant Diseases ; Plant Extracts/pharmacology ; Xanthomonas ; }, abstract = {Xanthomonas oryzae pv. oryzae (Xoo), a pathogen responsible for rice bacterial leaf blight, produces biofilm to protect viable Xoo cells from antimicrobial agents. A study was conducted to determine the potency of Acacia mangium methanol (AMMH) leaf extract as a Xoo biofilm inhibitor. Four concentrations (3.13, 6.25, 9.38, and 12.5 mg/mL) of AMMH leaf extract were tested for their ability to inhibit Xoo biofilm formation on a 96-well microtiter plate. The results showed that the negative controls had the highest O.D. values from other treatments, indicating the intense formation of biofilm. This was followed by the positive control (Streptomycin sulfate, 0.2 mg/mL) and AMMH leaf extract at concentration 3.13 mg/mL, which showed no significant differences in their O.D. values (1.96 and 1.57, respectively). All other treatments at concentrations of 6.25, 9.38, and 12.5 mg/mL showed no significant differences in their O.D. values (0.91, 0.79, and 0.53, respectively). For inhibition percentages, treatment with concentration 12.5 mg/mL gave the highest result (81.25%) followed by treatment at concentrations 6.25 and 9.38 mg/mL that showed no significant differences in their inhibition percentage (67.75% and 72.23%, respectively). Concentration 3.13 mg/mL resulted in 44.49% of biofilm inhibition and the positive control resulted in 30.75% of biofilm inhibition. Confocal laser scanning microscopy (CLSM) analysis of Xoo biofilm inhibition and breakdown showed the presence of non-viable Xoo cells and changes in aggregation size due to increase in AMMH leaf extract concentration. Control slides showed the absence of Xoo dead cells.}, } @article {pmid32074086, year = {2019}, author = {Goudarzi, M and Mohammadi, A and Amirpour, A and Fazeli, M and Nasiri, MJ and Hashemi, A and Goudarzi, H}, title = {Genetic diversity and biofilm formation analysis of Staphylococcus aureus causing urinary tract infections in Tehran, Iran.}, journal = {Journal of infection in developing countries}, volume = {13}, number = {9}, pages = {777-785}, doi = {10.3855/jidc.11329}, pmid = {32074086}, issn = {1972-2680}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms ; Humans ; Iran/epidemiology ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/isolation & purification ; Polymerase Chain Reaction ; Prevalence ; Staphylococcal Infections/epidemiology/*microbiology ; Staphylococcus aureus/drug effects/*genetics/isolation & purification ; Urinary Tract Infections/epidemiology/*microbiology ; Virulence Factors ; }, abstract = {INTRODUCTION: Over the past decades, prevalence of biofilm-forming Staphylococcus aureus strains has significantly increased in urinary tract infections. The aim of this study was to investigate prevalence of biofilm forming and adhesion encoding genes and to analyze distribution of different agr and spa types in S. aureus isolates.

METHODOLOGY: In the present study, 75 S. aureus isolates obtained from patients with urinary tract infections were examined for susceptibility to antimicrobial agents. Adhesion, biofilm, and spa encoding genes were detected by PCR screening; agr types were determined using multiplex PCR.

RESULTS: Among the 75 isolates, 72% were biofilm producers and 28% were non-biofilm producers. Notably, the ability to produce biofilm was higher among MRSA strains ompared to MSSA strains. The most prevalent biofilm forming gene was icaD (77.3%), followed by icaA (76%), icaB (57.3%) and icaC (50.7%). Adhesion genes clfA, clfB, fnbB, can, fnbA, ebp and bap were detected in 94.7%, 92%, 68%, 64%, 64%, 60% and 5.3% of the isolates, respectively. The spa types t426 and t7789 were found among the non-MDR isolates. It was found that t790, t084, t7789 and t325 spa types were biofilm producers, while t426 and t1339 spa types were non-biofilm producers.

CONCLUSION: Biofilm encoding genes icaD and spa type t790 and agr type III were the most prevalent factors among MDR biofilm producer isolates. The study emphasized that identification of genes and characterization of molecular types involved in biofilm formation should be considered.}, } @article {pmid32072274, year = {2020}, author = {Ren, X and Wang, L and Chen, W}, title = {Oxytropis glabra DC. Inhibits Biofilm Formation of Staphylococcus epidermidis by Down-Regulating ica Operon Expression.}, journal = {Current microbiology}, volume = {77}, number = {7}, pages = {1167-1173}, doi = {10.1007/s00284-019-01847-w}, pmid = {32072274}, issn = {1432-0991}, support = {Grant 31260026//the National Science Foundation of China/ ; Grant NCET-11-1071//Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province (CN)/ ; Grant 2009JC07//Society of the Friendly Sons of St. Patrick for the Relief of Emigrants from Ireland (US)/ ; }, mesh = {Biofilms/*drug effects ; Down-Regulation/*drug effects ; Operon/drug effects ; *Oxytropis ; Plant Extracts/chemistry/*pharmacology ; Staphylococcus epidermidis/*drug effects/genetics ; }, abstract = {Staphylococcus epidermidis is one of the main causes of medical device-related infections and bovine mastitis owing to its biofilm-forming abilities. Oxytropis glabra DC. is one of the most widespread Fabaceae species and used as a Chinese herbal formulation in Western China. Our research investigated the effects of O. glabra on the biofilm formation of S. epidermidis and the possible inhibiting mechanism. The biofilm-forming reference strain, S. epidermidis SE-1 (ATCC 35,984), was employed as a model and semi-quantitative biofilm assay was performed to evaluate the antibiofilm activity of O. glabra. The exopolysaccharides (EPS) production and expression of ica operon were studied to explore the possible antibiofilm mechanism using thin-layer chromatography and quantitative real-time PCR assay, respectively. The results obtained indicated that O. glabra decoction at 7.5 mg mL[-1] significantly inhibited biofilm formation by about 95% without affecting cell growth of S. epidermidis. Two hydrolysis productions of EPS were significantly decreased by 64% and 54% with the addition of 7.5 mg mL[-1]O. glabra and the expression of icaR was significantly up-regulated 2.2-times, whereas icaB was significantly down-regulated more than 50% by 7.5 mg mL[-1]O. glabra. These findings suggest a potential application for O. glabra as a promising candidate for the exploration of new drugs against S. epidermidis biofilm-associated infections.}, } @article {pmid32071069, year = {2020}, author = {Sun, Y and Li, Y and Luo, Q and Huang, J and Chen, J and Zhang, R and Wang, X}, title = {LuxS/AI-2 Quorum Sensing System in Edwardsiella piscicida Promotes Biofilm Formation and Pathogenicity.}, journal = {Infection and immunity}, volume = {88}, number = {5}, pages = {}, pmid = {32071069}, issn = {1098-5522}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/*genetics ; Edwardsiella/*genetics ; Gene Deletion ; Gene Expression Regulation, Bacterial/genetics ; Quorum Sensing/*genetics ; Transcriptome/genetics ; Virulence/*genetics ; }, abstract = {LuxS/AI-2 is an important quorum sensing system which affects the growth, biofilm formation, virulence, and metabolism of bacteria. LuxS is encoded by the luxS gene, but how this gene is associated with a diverse array of physiological activities in Edwardsiella piscicida (E. piscicida) is not known. Here, we constructed an luxS gene mutant strain, the △luxS strain, to identify how LuxS/AI-2 affects pathogenicity. The results showed that LuxS was not found in the luxS gene mutant strain, and this gene deletion decreased E. piscicida growth compared to that of the wild-type strain. Meanwhile, the wild-type strain significantly increased penetration and motility in mucin compared to levels with the △luxS strain. The 50% lethal dose (LD50) of the E. piscicida △luxS strain for zebrafish was significantly higher than that of the wild-type strain, which suggested that the luxS gene deletion could attenuate the strain's virulence. The AI-2 activities of EIB202 were 56-fold higher than those in the △luxS strain, suggesting that the luxS gene promotes AI-2 production. Transcriptome results demonstrated that between cells infected with the △luxS strain and those infected with the wild-type strain 46 genes were significantly differentially regulated, which included 34 upregulated genes and 12 downregulated genes. Among these genes, the largest number were closely related to cell immunity and signaling systems. In addition, the biofilm formation ability of EIB202 was significantly higher than that of the △luxS strain. The supernatant of EIB202 increased the biofilm formation ability of the △luxS strain, which suggested that the luxS gene and its product LuxS enhanced biofilm formation in E. piscicida All results indicate that the LuxS/AI-2 quorum sensing system in E. piscicida promotes its pathogenicity through increasing a diverse array of physiological activities.}, } @article {pmid32070890, year = {2020}, author = {Shabbir, S and Faheem, M and Ali, N and Kerr, PG and Wang, LF and Kuppusamy, S and Li, Y}, title = {Periphytic biofilm: An innovative approach for biodegradation of microplastics.}, journal = {The Science of the total environment}, volume = {717}, number = {}, pages = {137064}, doi = {10.1016/j.scitotenv.2020.137064}, pmid = {32070890}, issn = {1879-1026}, mesh = {Biodegradation, Environmental ; *Biofilms ; Microplastics ; Polyethylene ; Water Pollutants, Chemical ; }, abstract = {Microplastics (MPs) have been gaining the attention of environmental researchers since the 1960s anecdotal reports of plastic entanglement and ingestion by marine creatures. Due to their increasing accretion in aquatic environments, as well as resistance towards degradation, marine litter research has focused on microplastics more recently. In the present study, a relatively new method of biodegradation was implemented for the biodegradation of three structurally different MPs i.e. polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET). Periphytic biofilm was used for this purpose in various backgrounds of carbon sources (glucose, peptone, and glucose and peptone). Biodegradation of MPs was estimated in terms of weight loss. It was observed that the addition of glucose enhanced the biodegradation of MPs by periphyton biofilm for all MPs (from 9.52%-18.02%, 5.95%-14.02% and 13.24-19.72% for PP, PE and PET respectively) after 60 days compared to natural biofilm alone. To the contrary, peptone, and glucose and peptone together, were inhibitory. Biodegradation was further confirmed by morphological changes observed using SEM, FTIR spectra and GPC lent further support to the results whereby new peaks appeared along with reduction in old peaks and decrease in peak intensities. MiSeq sequencing shows that Deinococcus-thermus > Proteobacteria > Cyanobacteria are the dominant phyla in natural biofilms, and their relative abundances increase after the addition of glucose. However, the abundances shifted to Deinococcus-thermus > Cyanobacteria > Firmicutes > Bacteroidetes, when the biofilms were treated with either peptone alone, or with glucose and peptone together. Therefore, the change in biodegradation capability might also be due to the change in the microbial community structures after addition of the C-sources. These experiments provide an innovative approach towards effective biodegradation of MPs using a relatively new environment-friendly method.}, } @article {pmid32070273, year = {2020}, author = {Chen, T and Dong, G and Zhang, S and Zhang, X and Zhao, Y and Cao, J and Zhou, T and Wu, Q}, title = {Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {36}, pmid = {32070273}, issn = {1471-2180}, support = {No.81971986//National Natural Science Foundation of China/International ; No.2019KY098//Health Department of Zhejiang Province of the People's Republic of China/International ; }, mesh = {Animals ; Biofilms/drug effects/*growth & development ; Culture Media/chemistry ; Disease Models, Animal ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Iron/*pharmacology ; Iron Chelating Agents/adverse effects ; Klebsiella pneumoniae/drug effects/genetics/*pathogenicity ; Lepidoptera/microbiology ; Liver Abscess/metabolism/*microbiology ; Virulence/drug effects ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses.

RESULTS: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P < 0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron-restricted conditions (P < 0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron-restricted conditions (P < 0.05).

CONCLUSIONS: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.}, } @article {pmid32070067, year = {2020}, author = {Hahn, MM and Gunn, JS}, title = {Salmonella Extracellular Polymeric Substances Modulate Innate Phagocyte Activity and Enhance Tolerance of Biofilm-Associated Bacteria to Oxidative Stress.}, journal = {Microorganisms}, volume = {8}, number = {2}, pages = {}, pmid = {32070067}, issn = {2076-2607}, support = {R21 AI156328/AI/NIAID NIH HHS/United States ; R01AI116917/NH/NIH HHS/United States ; }, abstract = {Salmonella enterica serovar Typhi causes 14.3 million acute cases of typhoid fever that are responsible for 136,000 deaths each year. Chronic infections occur in 3%-5% of those infected and S. Typhi persists primarily in the gallbladder by forming biofilms on cholesterol gallstones, but how these bacterial communities evade host immunity is not known. Salmonella biofilms produce several extracellular polymeric substances (EPSs) during chronic infection, which are hypothesized to prevent pathogen clearance either by protecting biofilm-associated bacteria from direct humoral attack or by modulating innate phagocyte interaction with biofilms. Using wild-type and EPS-deficient planktonic and biofilm Salmonella, the direct attack hypothesis was tested by challenging biofilms with human serum and antimicrobial peptides. Biofilms were found to be tolerant to these molecules, but these phenotypes were independent of the tested EPSs. By examining macrophage and neutrophil responses, new roles for biofilm-associated capsular polysaccharides and slime polysaccharides were identified. The S. Typhi Vi antigen was found to modulate innate immunity by reducing macrophage nitric oxide production and neutrophil reactive oxygen species (ROS) production. The slime polysaccharides colanic acid and cellulose were found to be immune-stimulating and represent a key difference between non-typhoidal serovars and typhoidal serovars, which do not express colanic acid. Furthermore, biofilm tolerance to the exogenously-supplied ROS intermediates hydrogen peroxide (H2O2) and hypochlorite (ClO) indicated an additional role of the capsular polysaccharides for both serovars in recalcitrance to H2O2 but not ClO, providing new understanding of the stalemate that arises during chronic infections and offering new directions for mechanistic and clinical studies.}, } @article {pmid32069253, year = {2019}, author = {Rodrigues, RS and Lima, NCDS and Taborda, RLM and Esquerdo, RP and Gama, AR and Nogueira, PA and Orlandi, PP and Matos, NB}, title = {Antibiotic resistance and biofilm formation in children with Enteropathogenic Escherichia coli (EPEC) in Brazilian Amazon.}, journal = {Journal of infection in developing countries}, volume = {13}, number = {8}, pages = {698-705}, doi = {10.3855/jidc.10674}, pmid = {32069253}, issn = {1972-2680}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Brazil ; Child ; Child, Preschool ; *Drug Resistance, Bacterial ; Enteropathogenic Escherichia coli/*drug effects/*growth & development/isolation & purification ; Escherichia coli Infections/*microbiology ; Female ; Gastroenteritis/*microbiology ; Hospitals ; Humans ; Infant ; Male ; }, abstract = {INTRODUCTION: Enteropathogenic Escherichia coli is an important causative agent of diarrhea in both developed and developing countries.

METHODOLOGY: We assessed the antibiotic resistance profile and the ability of 71 Enteropathogenic Escherichia coli (EPEC) isolates from children in the age group 6 years, or younger, to form biofilm. These children were hospitalized in Cosme and Damião Children Hospital in Porto Velho, Western Brazilian Amazon, between 2010 and 2012, with clinical symptoms of acute gastroenteritis.

RESULTS: The highest frequency of atypical EPEC (aEPEC) isolates reached 83.1% (59/71). Most EPEC isolates presented Localized Adherence Like (LAL) pattern in HEp-2 cells (57.7% - 41/71). Biofilm production was observed in 33.8% (24/71) of EPEC isolates, and it means statistically significant association with shf gene (p = 0.0254). The highest antimicrobial resistance rates and a large number of multiresistant isolates 67.6% (48/71), regarded cefuroxime (CXM), ampicillin (AMP), trimethoprim-sulfamethoxazole (SXT) and tetracycline (TET), respectively, mainly in typical EPEC (tEPEC). Furthermore, 96% (68/71) of EPEC isolates in the present study were resistant to at least one antibiotic, whereas only 3 isolates were sensitive to all the tested drugs.

CONCLUSION: Based on our findings, there was increased aEPEC identification. EPEC isolates showed high resistance rate; most strains showed multiresistance; thus, they work as warning about the continuous need of surveillance towards antimicrobial use. Besides, the ability of forming biofilm was evidenced by the EPEC isolates. This outcome is worrisome, since it is a natural resistance mechanism of bacteria.}, } @article {pmid32069025, year = {2020}, author = {Yuan, Z and Lin, C and He, Y and Tao, B and Chen, M and Zhang, J and Liu, P and Cai, K}, title = {Near-Infrared Light-Triggered Nitric-Oxide-Enhanced Photodynamic Therapy and Low-Temperature Photothermal Therapy for Biofilm Elimination.}, journal = {ACS nano}, volume = {14}, number = {3}, pages = {3546-3562}, doi = {10.1021/acsnano.9b09871}, pmid = {32069025}, issn = {1936-086X}, mesh = {Adsorption ; Anti-Bacterial Agents/chemistry/*pharmacology ; Arginine/chemistry/*pharmacology ; Biofilms/drug effects ; Indocyanine Green/chemistry/*pharmacology ; Indoles/chemistry/*pharmacology ; Infrared Rays ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Molecular Structure ; Nanoparticles/chemistry ; Nitric Oxide/chemistry/*pharmacology ; Particle Size ; Photothermal Therapy ; Polymers/chemistry/*pharmacology ; Porosity ; Staphylococcus aureus/drug effects ; Surface Properties ; *Temperature ; }, abstract = {Photothermal treatment (PTT) involving a combination of therapeutic modalities recently emerged as an efficient alternative for combating biofilm. However, PTT-related local high temperature may destroy the surrounding healthy tissues. Herein, we present an all-in-one phototherapeutic nanoplatform consisting of l-arginine (l-Arg), indocyanine green (ICG), and mesoporous polydopamine (MPDA), namely, AI-MPDA, to eliminate the already-formed biofilm. The fabrication process included surface modification of MPDA with l-Arg and further adsorption of ICG via π-π stacking. Under near-infrared (NIR) exposure, AI-MPDA not only generated heat but also produced reactive oxygen species, causing a cascade catalysis of l-Arg to release nitric oxide (NO). Under NIR irradiation, biofilm elimination was attributed to the NO-enhanced photodynamic therapy and low-temperature PTT (≤45 °C). Notably, the NIR-triggered all-in-one strategy resulted in severe destruction of bacterial membranes. The phototherapeutic AI-MPDA also displayed good cytocompatibility. NIR-irradiated AI-MPDA nanoparticles not only prevented bacterial colonization but also realized a rapid recovery of infected wounds. More importantly, the all-in-one phototherapeutic platform displayed effective biofilm elimination with an efficiency of around 100% in a abscess formation model. Overall, this low-temperature phototherapeutic platform provides a reliable tool for combating already-formed biofilms in clinical applications.}, } @article {pmid32066216, year = {2020}, author = {Shin, DS and Rhee, KJ and Eom, YB}, title = {Effect of Probiotic Clostridium butyricum NCTC 7423 Supernatant on Biofilm Formation and Gene Expression of Bacteroides fragilis.}, journal = {Journal of microbiology and biotechnology}, volume = {30}, number = {3}, pages = {368-377}, pmid = {32066216}, issn = {1738-8872}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteroides fragilis/drug effects/*physiology ; *Biofilms ; *Clostridium butyricum ; Gene Expression ; Gene Expression Regulation, Bacterial/*drug effects ; Probiotics/*pharmacology ; }, abstract = {Enterotoxigenic Bacteroides fragilis (ETBF) is the main pathogen causing severe inflammatory diseases and colorectal cancer. Its biofilm plays a key role in the development of colorectal cancer. The objective of this study was to determine the antagonistic effects of cell-free supernatants (CFS) derived from Clostridium butyricum against the growth and biofilm of ETBF. Our data showed that C. butyricum CFS inhibited the growth of B. fragilis in planktonic culture. In addition, C. butyricum CFS exhibited an antibiofilm effect by inhibiting biofilm development, disassembling preformed biofilms and reducing the metabolic activity of cells in biofilms. Using confocal laser scanning microscopy, we found that C. butyricum CFS significantly suppressed the proteins and extracellular nucleic acids among the basic biofilm components. Furthermore, C. butyricum CFS significantly downregulated the expression of virulence- and efflux pump-related genes including ompA and bmeB3 in B. fragilis. Our findings suggest that C. butyricum can be used as biotherapeutic agent by inhibiting the growth and biofilm of ETBF.}, } @article {pmid32065820, year = {2019}, author = {Nor A'shimi, MH and Alattraqchi, AG and Mohd Rani, F and A Rahman, NI and Ismail, S and Abdullah, FH and Othman, N and Cleary, DW and Clarke, SC and Yeo, CC}, title = {Biocide susceptibilities and biofilm-forming capacities of Acinetobacter baumannii clinical isolates from Malaysia.}, journal = {Journal of infection in developing countries}, volume = {13}, number = {7}, pages = {626-633}, doi = {10.3855/jidc.11455}, pmid = {32065820}, issn = {1972-2680}, mesh = {Acinetobacter Infections/epidemiology/*microbiology ; Acinetobacter baumannii/*drug effects/*growth & development/isolation & purification ; Benzalkonium Compounds/pharmacology ; Benzethonium/pharmacology ; Biofilms/*drug effects/*growth & development ; Chlorhexidine/analogs & derivatives/pharmacology ; Cross Infection/epidemiology/microbiology ; Disinfectants/*pharmacology ; *Drug Resistance, Bacterial ; Humans ; Malaysia/epidemiology ; Microbial Sensitivity Tests ; Prevalence ; }, abstract = {INTRODUCTION: Acinetobacter baumannii is a Gram-negative nosocomial pathogen that has the capacity to develop resistance to all classes of antimicrobial compounds. However, very little is known regarding its susceptibility to biocides (antiseptics and disinfectants) and capacity to form biofilms, particularly for Malaysian isolates.

AIM: To determine the susceptibility of A. baumannii isolates to commonly-used biocides, investigate their biofilm-forming capacities and the prevalence of biocide resistance and biofilm-associated genes.

METHODOLOGY: . The minimum inhibitory concentration (MIC) values of 100 A. baumannii hospital isolates from Terengganu, Malaysia, towards the biocides benzalkonium chloride (BZK), benzethonium chloride (BZT) and chlorhexidine digluconate (CLX), were determined by broth microdilution. The isolates were also examined for their ability to form biofilms in 96-well microplates. The prevalence of biocide resistance genes qacA, qacE and qacDE1 and the biofilm-associated genes bap and abaI were determined by polymerase chain reaction (PCR).

RESULTS: Majority of the A. baumannii isolates (43%) showed higher MIC values (> 50 µg/mL) for CLX than for BZK (5% for MIC > 50 µg/mL) and BZT (9% for MIC > 50 µg/mL). The qacDE1 gene was predominant (63%) followed by qacE (28%) whereas no isolate was found harbouring qacA. All isolates were positive for the bap and abaI genes although the biofilm-forming capacity varied among the isolates.

CONCLUSION: The Terengganu A. baumannii isolates showed higher prevalence of qacDE1 compared to qacE although no correlation was found with the biocides' MIC values. No correlation was also observed between the isolates' biofilm-forming capacity and the MIC values for the biocides.}, } @article {pmid32064391, year = {2020}, author = {Ripa, R and Shen, AQ and Funari, R}, title = {Detecting Escherichia coli Biofilm Development Stages on Gold and Titanium by Quartz Crystal Microbalance.}, journal = {ACS omega}, volume = {5}, number = {5}, pages = {2295-2302}, pmid = {32064391}, issn = {2470-1343}, abstract = {Bacterial biofilms are responsible for persistent infections and biofouling, raising serious concerns in both medical and industrial processes. These motivations underpin the need to develop methodologies to study the complex biological structures of biofilms and prevent their formation on medical implants, tools, and industrial apparatuses. Here, we report the detailed comparison of Escherichia coli biofilm development stages (adhesion, maturation, and dispersion) on gold and titanium surfaces by monitoring the changes in both frequency and dissipation of a quartz crystal microbalance (QCM) device, a cheap and reliable microgravimetric sensor which allows the real-time and label-free characterization of various stages of biofilm development. Although gold is the most common electrode material used for QCM sensors, the titanium electrode is also readily available for QCM sensors; thus, QCM sensors with different metal electrodes serve as a simple platform to probe how pathogens interact with different metal substrates. The QCM outcomes are further confirmed by atomic force microscopy and crystal violet staining, thus validating the effectiveness of this surface sensitive sensor for microbial biofilm research. Moreover, because QCM technology can easily modify the substrate types and coatings, QCM sensors also provide well-controlled experimental conditions to study antimicrobial surface treatments and eradication procedures, even on mature biofilms.}, } @article {pmid32059494, year = {2020}, author = {Fagerlund, A and Heir, E and Møretrø, T and Langsrud, S}, title = {Listeria Monocytogenes Biofilm Removal Using Different Commercial Cleaning Agents.}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {4}, pages = {}, pmid = {32059494}, issn = {1420-3049}, support = {262306//Norwegian Research Funding for Agriculture and Food Industry/ ; 221663//Norwegian Research Funding for Agriculture and Food Industry/ ; }, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Colony Count, Microbial ; Disinfectants/*pharmacology ; Disinfection/methods ; Food Contamination ; Food Handling/methods ; *Food Microbiology ; Food-Processing Industry/methods ; Humans ; Listeria monocytogenes/*drug effects/pathogenicity ; Temperature ; }, abstract = {Effective cleaning and disinfection (C&D) is pivotal for the control of Listeria monocytogenes in food processing environments. Bacteria in biofilms are protected from biocidal action, and effective strategies for the prevention and removal of biofilms are needed. In this study, different C&D biofilm control strategies on pre-formed L. monocytogenes biofilms on a conveyor belt material were evaluated and compared to the effect of a conventional chlorinated, alkaline cleaner (agent A). Bacterial reductions up to 1.8 log were obtained in biofilms exposed to daily C&D cycles with normal user concentrations of alkaline, acidic, or enzymatic cleaning agents, followed by disinfection using peracetic acid. No significant differences in bactericidal effects between the treatments were observed. Seven-day-old biofilms were more tolerant to C&D than four-day-old biofilms. Attempts to optimize biofilm eradication protocols for four alkaline, two acidic, and one enzymatic cleaning agent, in accordance with the manufacturers' recommendations, were evaluated. Increased concentrations, the number of subsequent treatments, the exposure times, and the temperatures of the C&D agents provided between 4.0 and >5.5 log reductions in colony forming units (CFU) for seven-day-old L. monocytogenes biofilms. Enhanced protocols of conventional and enzymatic C&D protocols have the potential for improved biofilm control, although further optimizations and evaluations are needed.}, } @article {pmid32059431, year = {2020}, author = {Meto, A and Colombari, B and Meto, A and Boaretto, G and Pinetti, D and Marchetti, L and Benvenuti, S and Pellati, F and Blasi, E}, title = {Propolis Affects Pseudomonas aeruginosa Growth, Biofilm Formation, eDNA Release and Phenazine Production: Potential Involvement of Polyphenols.}, journal = {Microorganisms}, volume = {8}, number = {2}, pages = {}, pmid = {32059431}, issn = {2076-2607}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen responsible for a wide range of clinical conditions, from mild infections to life-threatening nosocomial biofilm-associated diseases, which are particularly severe in susceptible individuals. The aim of this in vitro study was to assess the effects of an Albanian propolis on several virulence-related factors of P. aeruginosa, such as growth ability, biofilm formation, extracellular DNA (eDNA) release and phenazine production. To this end, propolis was processed using three different solvents and the extracted polyphenolic compounds were identified by means of high performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) analysis. As assessed by a bioluminescence-based assay, among the three propolis extracts, the ethanol (EtOH) extract was the most effective in inhibiting both microbial growth and biofilm formation, followed by propylene glycol (PG) and polyethylene glycol 400 (PEG 400) propolis extracts. Furthermore, Pseudomonas exposure to propolis EtOH extract caused a decrease in eDNA release and phenazine production. Finally, caffeic acid phenethyl ester (CAPE) and quercetin decreased upon propolis EtOH extract exposure to bacteria. Overall, our data add new insights on the anti-microbial properties of a natural compound, such as propolis against P. aeruginosa. The potential implications of these findings will be discussed.}, } @article {pmid32058691, year = {2020}, author = {Konai, MM and Barman, S and Issa, R and MacNeil, S and Adhikary, U and De, K and Monk, PN and Haldar, J}, title = {Hydrophobicity-Modulated Small Antibacterial Molecule Eradicates Biofilm with Potent Efficacy against Skin Infections.}, journal = {ACS infectious diseases}, volume = {6}, number = {4}, pages = {703-714}, doi = {10.1021/acsinfecdis.9b00334}, pmid = {32058691}, issn = {2373-8227}, support = {MR/S004688/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Amino Acids/chemistry ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Female ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; HEK293 Cells ; Humans ; *Hydrophobic and Hydrophilic Interactions ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Skin Diseases, Bacterial/*drug therapy ; Small Molecule Libraries/*chemistry ; Staphylococcal Infections/drug therapy/microbiology ; Structure-Activity Relationship ; }, abstract = {The role of molecular arrangement of hydrophobic and hydrophilic groups for designing membrane-active molecules remains largely ambiguous. To explore this aspect, herein we report a series of membrane-active small molecules by varying the spatial distribution of hydrophobic groups. The two terminal amino groups of linear triamines such as diethylene triamine, bis(trimethylene)triamine, and bis(hexamethylene)triamine were conjugated with cationic amino acids bearing variable side chain hydrophobicity (such as diaminobutyric acid, ornithine, and lysine). The hydrophobicity was also modulated through conjugation of different long chain fatty acids with the central secondary amino group of the triamine. Molecules with constant backbone hydrophobicity displayed an enhanced antibacterial activity and decreased hemolytic activity upon increasing the side chain hydrophobicity of amino acids. On the other hand, increased hydrophobicity in the backbone introduced a slight hemolytic activity but a higher increment in antibacterial activity, resulting in better selective antibacterial compounds. The optimized lead compound derived from structure-activity-relationship (SAR) studies was the dodecanoyl analogue of a lysine series of compounds consisting of bis(hexamethylene)triamine as the backbone. This compound was active against various Gram-positive and Gram-negative bacteria at a low concentration (MIC ranged between 3.1 and 6.3 μg/mL) and displayed low toxicity toward mammalian cells (HC50 = 890 μg/mL and EC50 against HEK = 85 μg/mL). Additionally, it was able to kill metabolically inactive bacterial cells and eradicate preformed biofilms of MRSA. This compound showed excellent activity in a mouse model of skin infection with reduction of ∼4 log MRSA burden at 40 mg/kg dose without any sign of skin toxicity even at 200 mg/kg. More importantly, it revealed potent efficacy in an ex vivo model of human skin infection (with reduction of 85% MRSA burden at 50 μg/mL), which indicates great potential of the compound as an antibacterial agent to treat skin infections.}, } @article {pmid32058164, year = {2020}, author = {Dash, DM and Osborne, WJ}, title = {Rapid biodegradation and biofilm-mediated bioremoval of organophosphorus pesticides using an indigenous Kosakonia oryzae strain -VITPSCQ3 in a Vertical-flow Packed Bed Biofilm Bioreactor.}, journal = {Ecotoxicology and environmental safety}, volume = {192}, number = {}, pages = {110290}, doi = {10.1016/j.ecoenv.2020.110290}, pmid = {32058164}, issn = {1090-2414}, mesh = {Biodegradation, Environmental ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Enterobacteriaceae/*enzymology/genetics/physiology ; Environmental Pollutants/*metabolism ; Insecticides/*metabolism ; Kinetics ; Organothiophosphates/*metabolism ; Organothiophosphorus Compounds/*metabolism ; Rhizosphere ; }, abstract = {The widespread use of pesticides has been one of the major anthropogenic sources of environmental pollution. Organophosphorus (OP) pesticides are predominantly used in agriculture due to their broad-spectrum insecticidal activity and chemical stability. The study was focused on the biodegradation of OP pesticides, Profenofos (PF) and Quinalphos (QP) in culture media using bacterium isolated from wetland paddy rhizosphere. The strain VITPSCQ3 showed higher pesticide tolerance, efficient biofilm formation and was capable of synthesizing organophosphate degrading enzymes. Based on the 16S rRNA gene sequencing the isolate exhibited maximum sequence similarity with Kosakinia oryzae (GenBank accession number: KR149275). Biodegradation assay with various concentrations of PF and QP (200, 400, 600 and 800 mg L[-1]) showed maximum degradation up to 82% and 92% within 48 h. The kinetic studies revealed the biodegradation rates (k) to be 0.0844 min[-1] and 0.107 min[-1] with half-lives (h) of 18 h and 14.8 h for PF and QP. The degradation products were identified by GCMS and possible degradation pathways were proposed using Insilico techniques. To the best of our knowledge, this is the first report on the biodegradation of PF and QP using Kosakonia oryzae. Bioremoval of PF and QP from aqueous solution was performed using the biofilm of VITPSCQ3 developed on selected substrates in a circulating Vertical-flow packed-bed biofilm (VFPBB) bioreactor. Charcoal, gravel and mushroom (Agaricus bisporus) were used as biofilm carriers. Mushroom showed strong biofilm formation with optimum biodegradation capacity of up to 96% for PF and 92% for QP within 120 min reaction time.}, } @article {pmid32057619, year = {2020}, author = {Dey, P and Parai, D and Banerjee, M and Hossain, ST and Mukherjee, SK}, title = {Naringin sensitizes the antibiofilm effect of ciprofloxacin and tetracycline against Pseudomonas aeruginosa biofilm.}, journal = {International journal of medical microbiology : IJMM}, volume = {310}, number = {3}, pages = {151410}, doi = {10.1016/j.ijmm.2020.151410}, pmid = {32057619}, issn = {1618-0607}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Ciprofloxacin/*pharmacology ; Flavanones/*pharmacology ; Macrophages/drug effects ; Mice ; Microbial Sensitivity Tests ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects ; Tetracycline/*pharmacology ; }, abstract = {The study aims to explore the combinatorial effect of naringin with antibiotics, ciprofloxacin and tetracycline on Pseudomonas aeruginosa biofilms. The antibiofilm efficacy of selected treatment regimes against P. aeruginosa biofilm were quantified by crystal violet assay, MTT assay, Congo red binding assay, and were visualized by confocal laser scanning microscopy and scanning electron microscopy. All the assays reflected antibiofilm activities, however, combinatorial performances of naringin with antibiotics were found to be more significant. A significant reduction in swimming and swarming motilities along with pellicle formation and altered colony morphology were observed as a result of combinatorial effect. The cytotoxicity of naringin and its antibiotic combinations was assayed on murine macrophage cell line. The applicability of such combinations was tested for their relative eradication against pre-formed biofilm on urinary catheter surface. This finding indicated that naringin potentiates the efficacy of both ciprofloxacin and tetracycline on P. aeruginosa biofilm in comparison to their solo treatment. The finding would help to open hitherto unexplored possibilities of establishing naringin as a potential antibiofilm agent and suggest on the possibility of its use in drug-herb combinations for managing biofilm-associated bacterial infections.}, } @article {pmid32056620, year = {2020}, author = {Sikder, MNA and Xu, G and Xu, H}, title = {Seasonal variability in taxonomic breadth of biofilm-dwelling ciliates in colonization surveys for marine bioassessment.}, journal = {Marine pollution bulletin}, volume = {151}, number = {}, pages = {110828}, doi = {10.1016/j.marpolbul.2019.110828}, pmid = {32056620}, issn = {1879-3363}, mesh = {Biodiversity ; *Biofilms ; *Ciliophora ; *Ecosystem ; *Environmental Monitoring ; Seasons ; Surveys and Questionnaires ; }, abstract = {To determine an optimal sampling strategy for collecting samples with an expected taxonomic breadth, a 1-year baseline colonization survey was conducted in Chinese coastal waters using glass slides as an artificial substratum for biofilm-dwelling ciliates. A total of 240 slide samples were collected at a depth of 1 m in a four-season cycle. The taxonomic composition and structure of the ciliate communities differed from spring to winter. The colonization dynamics in taxonomic distinctness showed a significant variability among the four seasons. Expectation tests on the pairs of average taxonomic distinctness indices demonstrated a seasonal variability in taxonomic breadth of the ciliates, with high expectation levels in spring and autumn and low levels in the other two seasons. These findings suggest that there was a significant seasonal variability in taxonomic breadth for colonization surveys of biofilm-dwelling ciliates, and that an optimal sampling strategy should be determined for bioassessment in marine ecosystems.}, } @article {pmid32056409, year = {2020}, author = {Panariello, BH and Azabi, AA and Mokeem, LS and AlMady, FA and Lippert, F and Hara, AT and Duarte, S}, title = {The effects of charcoal dentifrices on Streptococcus mutans biofilm development and enamel demineralization.}, journal = {American journal of dentistry}, volume = {33}, number = {1}, pages = {12-16}, pmid = {32056409}, issn = {0894-8275}, mesh = {Animals ; Biofilms ; Cariostatic Agents ; Cattle ; Charcoal ; Dental Enamel ; *Dentifrices ; Fluorides ; Sodium Fluoride ; Streptococcus mutans ; *Tooth Demineralization ; Tooth Remineralization ; }, abstract = {PURPOSE: To evaluate the in vitro effects of commercially available charcoal dentifrices on Streptococcus mutans biofilm development and their ability to prevent enamel demineralization.

METHODS: Streptococcus mutans biofilm was formed on polished bovine enamel specimens (n= 9 per treatment), and treated twice-daily for 120 seconds over the course of 5 days with: charcoal dentifrice containing fluoride (1,000 ppm F) (CF+), fluoride-free charcoal dentifrice (CF-), regular fluoride (1,100 ppm F) dentifrice (F+), or regular fluoride-free dentifrice (F-). Chlorhexidine (CHX, 0.12%) and deionized water (DIW) were used as positive and negative controls, respectively. Biofilms were analyzed for bacterial viability (colony-forming units, CFU). The pH of the medium was measured daily. Enamel specimens were analyzed using Vickers microhardness (HV) and transversal microradiography (TMR). Data were analyzed using one-way ANOVA followed by post-hoc tests (α= 0.05).

RESULTS: F+ showed higher pH values than CF+ and CF-, and CF- presented higher pH than CF+, showing that CF+ did not have inhibitory effects on the acidogenicity of cariogenic biofilms. CFU was significantly decreased when specimens were treated with CF+, CF- and F+, compared to specimens treated with DIW (P≤ 0.035) or F- (P≤ 0.001), respectively. However, the reduction observed was minimal (approximately 1 log). CF+ and CF- were less effective than F+ in preventing enamel demineralization as determined using HV (P= 0.041 and P= 0.003, respectively) and TMR (P≤ 0.001). Both charcoal dentifrices (CF+, CF-) did not show relevant inhibition of S. mutans biofilm growth. Additionally, neither product prevented enamel demineralization compared to a regular fluoride-containing dentifrice.

CLINICAL SIGNIFICANCE: The tested charcoal dentifrices did not exhibit anticaries potential.}, } @article {pmid32055912, year = {2020}, author = {Gao, XY and Liu, Y and Miao, LL and Liu, ZP}, title = {Pseudomonas sp. AOB-7 utilizes PHA granules as a sustained-release carbon source and biofilm carrier for aerobic denitrification of aquaculture water.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {7}, pages = {3183-3192}, doi = {10.1007/s00253-020-10452-y}, pmid = {32055912}, issn = {1432-0614}, support = {KFJ-BRP-009//Chinese Academy of Sciences/ ; }, mesh = {3-Hydroxybutyric Acid/biosynthesis ; Aerobiosis ; Aquaculture ; Biodegradation, Environmental ; Biofilms/*growth & development ; Carbon/metabolism ; *Denitrification ; Nitrates/isolation & purification ; Polyhydroxyalkanoates/*metabolism ; Pseudomonas/growth & development/*metabolism ; Water Pollutants, Chemical/isolation & purification ; Water Purification ; }, abstract = {Nitrate accumulation causes long-time threat to aquatic animals in recirculating aquaculture system (RAS); thus, nitrate removal is also required in RASs. However, the lack of carbon sources makes denitrification difficult to function. Nitrate removal performance of an aerobic denitrifying and extracellular polyhydroxyalkanoate depolymerase-producing bacterium, Pseudomonas sp. AOB-7, using polyhydroxyalkanoate (PHA) granules as a solid sustained-release carbon source in RAS was evaluated. With the initial nitrate-N concentration of 140 mg/L, the high denitrification rates of 0.056 g NO3[-]-N L[-1] day[-1] and 0.035 g NO3[-]-N L[-1] day[-1] were achieved in denitrification medium containing poly-β-hydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), respectively. Significant erosions and pits formed on the surface of the granules made them a good biofilm carrier for AOB-7, and 3-hydroxybutyrate (3-HB) monomer was the major product released to aquatic phase, which was benefit to animals. SEM photos showed that AOB-7 entered and attached on the inside of the PHA particle holes. A 4-week application trial was conducted to reveal the effects of PHB (AOB-7) denitrifying agent and 3-HB produced on growth of zebrafish (Brachydanio rerio) by adding 0.1% (w/v) PHB (AOB-7) denitrifying agent. Result indicated that PHB (AOB-7) denitrifying agent can significantly reduce nitrate-N content in RASs. Compared with the control group, feed coefficient ratio reduced by 18% and weight gain ratio increased by 29% in the PHB (AOB-7) denitrifying agent group. 3-HB monomer produced during the denitrification was speculated to function as a prebiotic and promote zebrafish growth. KEY POINTS: • AOB-7 showed a good aerobic denitrifying ability on PHA granules as sustained-release C source. • PHB (AOB-7) denitrifying agent can significantly reduce nitrate content in RAS. • R-3-HB monomer was the major product released to aquatic phase and function as a prebiotic.}, } @article {pmid32054862, year = {2020}, author = {Van Nguyen, P and Plocek, V and Váchová, L and Palková, Z}, title = {Glucose, Cyc8p and Tup1p regulate biofilm formation and dispersal in wild Saccharomyces cerevisiae.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {7}, pmid = {32054862}, issn = {2055-5008}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Culture Media/chemistry ; Gene Expression Regulation, Fungal ; Glucose/*metabolism ; Mutation ; Nuclear Proteins/*genetics/metabolism ; Repressor Proteins/*genetics/metabolism ; Saccharomyces cerevisiae/genetics/*physiology ; Saccharomyces cerevisiae Proteins/*genetics/metabolism ; Surface Properties ; }, abstract = {Saccharomyces cerevisiae is a mainly beneficial yeast, widely used in the food industry. However, there is growing evidence of its potential pathogenicity, leading to fungemia and invasive infections. The medical impact of yeast pathogens depends on formation of biofilms: multicellular structures, protected from the environment. Cell adhesion is a prerequisite of biofilm formation. We investigated the adherence of wild and genetically modified S. cerevisiae strains, formation of solid-liquid interface biofilms and associated regulation. Planktonic and static cells of wild strain BRF adhered and formed biofilms in glucose-free medium. Tup1p and Cyc8p were key positive and negative regulators, respectively. Glucose caused increased Cyc8p levels and blocked cell adhesion. Even low glucose levels, comparable with levels in the blood, allowed biofilm dispersal and release of planktonic cells. Cyc8p could thus modulate cell adhesion in different niches, dependently on environmental glucose level, e.g., high-glucose blood versus low-glucose tissues in host organisms.}, } @article {pmid32051871, year = {2020}, author = {Manilal, A and Sabu, KR and Shewangizaw, M and Aklilu, A and Seid, M and Merdikios, B and Tsegaye, B}, title = {In vitro antibacterial activity of medicinal plants against biofilm-forming methicillin-resistant Staphylococcus aureus: efficacy of Moringa stenopetala and Rosmarinus officinalis extracts.}, journal = {Heliyon}, volume = {6}, number = {1}, pages = {e03303}, pmid = {32051871}, issn = {2405-8440}, abstract = {The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is slowly rising in Ethiopia for the past few decades. Therefore, novel classes of antibiotics are indispensable to combat the increased incidence of newly emerging multidrug-resistant bacteria like MRSA. Terrestrial flora is considered as a reservoir of novel bioactive secondary metabolites as they have provided us with the largest array of natural products. In this background, the present study is intended to evaluate the in-vitro antibacterial efficacy of five medicinal plants (Ocimum lamiifolium Hochst. ex Benth., Rosmarinus officinalis L, Catharanthus roseus Linn., Azadirachta indica A. Juss and Moringa stenopetala Bac) against a panel of seven biofilm-forming MRSA. The leaves of the plants were extracted in organic solvents of varying polarity and the resultant crude extracts of respective medicinal plants were inspected for their antimicrobial activity by well diffusion technique. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the plant extracts against MRSA were determined by the broth dilution method. Besides, an anti-biofilm assay of the most potent plant extract was also performed, after which its chemical constituents were delineated by combined Gas Chromatographic and Mass Spectroscopic profiling (GC-MS). The results revealed that, of the five plants, three species including M. stenopetala, R. officinalis, and O. lamifolium exhibited significant antibacterial activity. Organic solvents with high and medium polarity were excellent in extracting antimicrobials compared to nonpolar solvents. The broadest and highest rank of activity was observed in the crude ethanolic extract of M. stenopetala. Based on the MIC/MBC ratio, the crude ethanolic extract of M. stenopetala was determined to be bacteriostatic. Anti-biofilm assay showed that the extract of M. stenopetala fairly inhibited the growth of MRSA in the preformed biofilm matrix. The GC-MS analysis of M. stenopetala revealed the presence of twelve compounds with antimicrobial activity. The present study provides new insight into the development of novel drug leads to the management of MRSA.}, } @article {pmid32051263, year = {2020}, author = {Harro, JM and Shirtliff, ME and Arnold, W and Kofonow, JM and Dammling, C and Achermann, Y and Brao, K and Parvizi, J and Leid, JG}, title = {Development of a Novel and Rapid Antibody-Based Diagnostic for Chronic Staphylococcus aureus Infections Based on Biofilm Antigens.}, journal = {Journal of clinical microbiology}, volume = {58}, number = {5}, pages = {}, pmid = {32051263}, issn = {1098-660X}, mesh = {Animals ; Antigens, Bacterial ; Biofilms ; *Osteomyelitis ; Rabbits ; *Staphylococcal Infections/diagnosis ; Staphylococcus aureus ; }, abstract = {Prosthetic joint infections are difficult to diagnose and treat due to biofilm formation by the causative pathogens. Pathogen identification relies on microbial culture that requires days to weeks, and in the case of chronic biofilm infections, lacks sensitivity. Diagnosis of infection is often delayed past the point of effective treatment such that only the removal of the implant is curative. Early diagnosis of an infection based on antibody detection might lead to less invasive, early interventions. Our study examined antibody-based assays against the Staphylococcus aureus biofilm-upregulated antigens SAOCOL0486 (a lipoprotein), glucosaminidase (a domain of SACOL1062), and SACOL0688 (the manganese transporter MntC) for detection of chronic S. aureus infection. We evaluated these antigens by enzyme-linked immunosorbent assay (ELISA) using sera from naive rabbits and rabbits with S. aureus-mediated osteomyelitis, and then we validated a proof of concept for the lateral flow assay (LFA). The SACOL0688 LFA demonstrated 100% specificity and 100% sensitivity. We demonstrated the clinical diagnostic utility of the SACOL0688 antigen using synovial fluid (SF) from humans with orthopedic implant infections. Elevated antibody levels to SACOL0688 in clinical SF specimens correlated with 91% sensitivity and 100% specificity for the diagnosis of S. aureus infection by ELISA. We found measuring antibodies levels to SACOL0688 in SF using ELISA or LFA provides a tool for the sensitive and specific diagnosis of S. aureus prosthetic joint infection. Development of the LFA diagnostic modality is a desirable, cost-effective option, potentially providing rapid readout in minutes for chronic biofilm infections.}, } @article {pmid32050878, year = {2020}, author = {Zeybek, Z and Türkmen, A}, title = {[Investigation of the Incidence of Legionella and Free-Living Amoebae in Swimming Pool Waters and Biofilm Specimens in Istanbul by Different Methods].}, journal = {Mikrobiyoloji bulteni}, volume = {54}, number = {1}, pages = {50-65}, doi = {10.5578/mb.68962}, pmid = {32050878}, issn = {0374-9096}, mesh = {*Amoeba/physiology ; *Biofilms ; *Environmental Monitoring/methods ; Incidence ; *Legionella/physiology ; *Swimming Pools ; Turkey ; *Water/parasitology ; *Water Microbiology ; }, abstract = {Legionella bacteria living in free form or in biofilm and free-living amoebae (FLA) can infect humans through swimming pools and can cause various diseases. FLA may also threaten the health of swimmers because they are capable of being hosts for Legionella and some other bacteria. The aim of this study was to investigate the presence of total aerobic heterotrophic bacteria (TAHB), FLA and Legionella bacteria in swimming pool waters and biofilm samples in Istanbul by using culture and FISH methods. Water plate count agar (wPCA), buffered charcoal yeast extract (BCYE) agar supplemented with glycinevancomycin-polymyxin-cycloheximide (GVPC) and Escherichia coli cultivated non-nutrient agar (NNA) were used for the culture of TAHB, Legionella and FLA. For the FISH method analysis , Leg 705 and Leg PNE1 probes labeled with fluorescent dye for Legionella and ACANTHA probe for Acanthamoeba genus FLA were used. Legionella pneumophila serogroup 1 ATCC 33152, L.pneumophila serogroup 3 ATCC 33155 and Acanthamoeba castellani ATCC 50373 were used as positive controls. TAHB were grown in 92% and 84% of water and biofilm samples. Although Legionella bacteria could not be grown in any of the water samples, it was detected in 6 (24%) water samples by FISH method. Although these bacteria could be grown in 1 (4%) of biofilm samples, 7 (28%) were detected by FISH method. FLA were found to be 16% by culture in water samples and 28% by FISH analysis. These amoebae were detected 8% and 20% in biofilm samples by culture and FISH method, respectively. It was determined that one of the isolates of FLA had thermotolerant activity (potentially pathogenic). L.pneumophila serogroup 1 was detected in one water sample and in four biofilm samples. According to the culture method, TAHB and FLA were found to be more common in water samples than in biofilm samples and Legionella bacteria were more common in biofilm samples than in water samples (p≤ 0.05). In the detection of Legionella bacteria, the superiority of FISH method compared to culture method was found to be statistically significant (p≤ 0.05). In this study, it was found that the number of TAHB in the controlled swimming pools was within the limits determined by the Ministry of Health (≤ 200 cfu/ml). It will be appropriate to examine both water and biofilm samples for the investigation of TAHB, FLA and Legionella. It may be appropriate to use both culture and FISH methods to detect the presence of FLA in water and biofilm samples. This study is the first study to investigate the presence of Legionella and FLA in swimming pools in Istanbul, and further studies are needed to examine more pool water and biofilm samples. With the data obtained, the health principles and controls of swimming pools will be re-considered and will be contributed to public health.}, } @article {pmid32050877, year = {2020}, author = {Altınok, Ö and Boral, B and Ergin, A and Eser, ÖK}, title = {[Existence of Biofilm and Biofilm-Associated Virulence Genes in Multi-Drug Resistant Invasive Acinetobacter baumannii Isolates].}, journal = {Mikrobiyoloji bulteni}, volume = {54}, number = {1}, pages = {40-49}, doi = {10.5578/mb.20204}, pmid = {32050877}, issn = {0374-9096}, mesh = {*Acinetobacter Infections/microbiology ; *Acinetobacter baumannii/drug effects/genetics ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Drug Resistance, Multiple, Bacterial/genetics ; Humans ; *Virulence/genetics ; }, abstract = {Acinetobacter baumannii is a multi-drug resistant (MDR) gram-negative pathogen leading to nosocomial infections. Hospital-acquired infections due to A.baumannii occur especially in patients hospitalized in intensive care units. Important infections related to this bacterium are pneumonia, bacteremia, endocarditis, skin and soft tissue, urinary tract infections and meningitis. Human transmission is usually through the hospital environment or through medical personnel. A.baumannii isolates increases their virulence not only being multiple resistance to antibiotics but as well as the ability to form biofilm. The biofilm formation of A.baumannii isolates were mostly related with genes encoding curli fiber (csgA), the chaperone-usher fimbria (csuE) and the outer membrane (ompA). The aim of this study was to demonstrate biofilm production and virulence genes in MDR invasive A.baumannii isolates. MDR and similarity status previously known invasive A.baumannii (n= 156) isolates were included in the study. Biofilm production was determined by quantitative microplate biofilm method. Virulence genes csgA, csuE, fimH, ompA and blaPER-1 were investigated by polymerase chain reaction (PCR). It was determined that 60.3% (94/156) of all the isolates formed biofilm. Of these 94 isolates, 17 were weak, 33 were medium and 44 were strong. The mean biomass forming capacity of the isolates was found to be 2.23 ± 0.0033. Among the isolates included in the study (n= 156) the frequency of csgA, csuE, ompA, fimH and blaPER-1 genes were 71.2%, 32.1%, 21.8%, 7.1% and 3.2% respectively. The frequency of csgA, ompA, bap, csuE, fimH virulence genes were found to be 41.5%, 24.5%, 20.2% and 5.3% among biofilm positive isolates respectively. Biofilm-forming isolates were most commonly found in pulsotype II 19.1% (18/94), pulsotype IX 17.0% (16/94) and pulsotype VI 12.8% (12/94). In this study, when the distribution of virulence genes were compAred with the isolates that have weak, medium and strong biofilm, all of the studied genes were found to be more abundant in isolates with strong and medium positive biofilm production. This has shown that excluding fimH gene, csgA, csuE and ompA genes have contributed to the biofilm formation in invasive A.baumannii isolates, respectively.}, } @article {pmid32050341, year = {2020}, author = {Huang, ZS and Wei, ZS and Xiao, XL and Li, BL and Ming, S and Cheng, XL and Jiao, HY}, title = {Bioconversion of Hg[0] into HA-Hg for simultaneous removal of Hg[0] and NO in a denitrifying membrane biofilm reactor.}, journal = {Chemosphere}, volume = {244}, number = {}, pages = {125544}, doi = {10.1016/j.chemosphere.2019.125544}, pmid = {32050341}, issn = {1879-1298}, mesh = {Bacteria ; Biofilms ; Bioreactors/*microbiology ; Denitrification ; Humic Substances ; Membranes ; Mercury/analysis/*metabolism ; Nitric Oxide/*metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Bacterial mercury oxidation coupled to denitrification offers great potential for simultaneous removal of elemental mercury (Hg[0]) and nitric oxide (NO) in a denitrifying membrane biofilm reactor (MBfR). Four potentially contributory mechanisms tested separately, namely, membrane gas separation, medium absorption, biosorption and biotransformation, which contributed 4.9%/7.2%, 8.1%/8.9%, 38.8%/9.5% and 48.2%/84.9% of overall Hg[0]/NO removal in MBfR. Herein, Hg[0] bio-oxidation, oxidative Hg[0] biosorption and denitrification played leading roles in simultaneous removal of Hg[0] and NO. Living microbes performed simultaneous Hg[0] bio-oxidation and denitrification, in which Hg[0] as electron donor was biologically oxidized to oxidized mercury (Hg[2+]), while NO as the terminal electron acceptor was denitrified to N2. The Hg[2+] further complexed with humic acids in extracellular polymeric substances via functional groups (-SH, -OH, -NH[-] and -COO[-]) and formed humic acids bound mercury (HA-Hg). Non-living microbial matrix performed oxidative Hg[0] biosorption, in which Hg[0] may be physically adsorbed by cellular matrix, then non-metabolically oxidized to Hg[2+] via oxidative complexation with -SH in humic acids and finally cleavage of S-H bond and surface charge transfer led to formation of HA-Hg. Therefore, bioconversion of Hg[0] to HA-Hg by Hg[0] bio-oxidation and oxidative Hg[0] biosorption coupled with NO denitrification to N2 dynamically cooperated to accomplish simultaneous removal of Hg[0] and NO in MBfR.}, } @article {pmid32049553, year = {2020}, author = {Jacquier, H and Vironneau, P and Dang, H and Verillaud, B and Lamers, G and Herman, P and Vicaut, E and Tessier, N and Bidet, P and Varon, E and Van Den Abbeele, T and Cambau, E and Bercot, B and Kania, R}, title = {Bacterial biofilm in adenoids of children with chronic otitis media. Part II: a case-control study of nasopharyngeal microbiota, virulence, and resistance of biofilms in adenoids.}, journal = {Acta oto-laryngologica}, volume = {140}, number = {3}, pages = {220-224}, doi = {10.1080/00016489.2020.1718749}, pmid = {32049553}, issn = {1651-2251}, mesh = {Adenoids/*microbiology ; Analysis of Variance ; Bacteria/*isolation & purification ; Biofilms ; Case-Control Studies ; Child ; Chronic Disease ; Drug Resistance, Bacterial ; Firmicutes/isolation & purification ; Haemophilus influenzae/isolation & purification/virology ; Humans ; Microbial Sensitivity Tests ; Nasopharynx/microbiology ; Otitis Media/*microbiology ; Staphylococcus aureus/isolation & purification ; Streptococcus pneumoniae/isolation & purification/virology ; Streptococcus pyogenes/isolation & purification/virology ; }, abstract = {Background: We previously described that adenoid tissue in children with chronic otitis media (COM) contained more mucosal biofilms than adenoid tissue removed for hypertrophy.Aims/objectives: The aim of the second part was to characterize nasopharyngeal microbiota and explore virulence of the most common middle ear pathogens.Material and methods: Bacteriological analysis was performed following a culture-based approach on the samples recovered from 30 patients of COM group (15 biofilm-positive and 15 biofilm-negative) and from 30 patients of a control group (15 biofilm-positive and 15 biofilm-negative). Virulence factors of Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae were investigated.Results: The most frequent species were Firmicutes followed by Proteobacteria and Actinobacteria. The presence of biofilm was statistically associated with an increase of the number of bacterial species and Firmicutes phylum regardless of the condition (case/control). No virulence factors associated with invasive isolates were found for the most common middle ear pathogens.Conclusions and significance: This case-control study demonstrated that the presence of COM plus biofilm was associated with a given microbiota which contained more Firmicutes. Our study allows a better understanding of physiopathological mechanisms involved in chronic otitis media and paves the way for further investigations.}, } @article {pmid32048958, year = {2020}, author = {Jang, YS and Mosolygó, T}, title = {Inhibition of Bacterial Biofilm Formation by Phytotherapeutics with Focus on Overcoming Antimicrobial Resistance.}, journal = {Current pharmaceutical design}, volume = {26}, number = {24}, pages = {2807-2816}, doi = {10.2174/1381612826666200212121710}, pmid = {32048958}, issn = {1873-4286}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Anti-Infective Agents/pharmacology ; Bacteria ; Biofilms ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, abstract = {Bacteria within biofilms are more resistant to antibiotics and chemical agents than planktonic bacteria in suspension. Treatment of biofilm-associated infections inevitably involves high dosages and prolonged courses of antimicrobial agents; therefore, there is a potential risk of the development of antimicrobial resistance (AMR). Due to the high prevalence of AMR and its association with biofilm formation, investigation of more effective anti-biofilm agents is required. From ancient times, herbs and spices have been used to preserve foods, and their antimicrobial, anti-biofilm and anti-quorum sensing properties are well known. Moreover, phytochemicals exert their anti-biofilm properties at sub-inhibitory concentrations without providing the opportunity for the emergence of resistant bacteria or harming the host microbiota. With increasing scientific attention to natural phytotherapeutic agents, numerous experimental investigations have been conducted in recent years. The present paper aims to review the articles published in the last decade in order to summarize a) our current understanding of AMR in correlation with biofilm formation and b) the evidence of phytotherapeutic agents against bacterial biofilms and their mechanisms of action. The main focus has been put on herbal anti-biofilm compounds tested to date in association with Staphylococcus aureus, Pseudomonas aeruginosa and food-borne pathogens (Salmonella spp., Campylobacter spp., Listeria monocytogenes and Escherichia coli).}, } @article {pmid32048076, year = {2020}, author = {Fu, H and Chen, F and Liu, W and Kong, W and Wang, C and Fang, X and Ye, J}, title = {Adding nutrients to the biocontrol strain JK-SH007 promotes biofilm formation and improves resistance to stress.}, journal = {AMB Express}, volume = {10}, number = {1}, pages = {32}, pmid = {32048076}, issn = {2191-0855}, support = {CX [16] 1005//the agricultural Independent Innovation Project of Jiangsu Province/ ; }, abstract = {Burkholderia pyrrocinia JK-SH007 is an important biocontrol strain for the prevention and treatment of poplar canker disease. Its powerful biocontrol function is inseparable from its successful colonization of poplar trees. Bacterial biofilms can ensure the long-term colonization of a host. To explore the mechanism of action of biofilms in the biocontrol process, we manipulated various exogenous factors to explore the morphology of the JK-SH007 biofilm in vitro. The addition of glycerol and MgSO4 to TSB medium stimulated biofilm production, increased the resistance of JK-SH007 to disease, enhanced the survival of JK-SH007 in nutrient-poor environments and maintained the antagonistic ability of JK-SH007 against the poplar canker pathogen. Therefore, we constructed and optimized a biofilm-forming system to produce a large number of stable JK-SH007 biofilms. The optimized system showed that the optimal incubation time for JK-SH007 biofilm formation was 14 h, the optimal temperature of the static culture was 25 °C, and the optimal pH was 5. The optimal medium for biofilm formation was TSB medium, 1% glycerol and 50 mM MgSO4. RT-qPCR experiments showed that an increase in the expression of the suhB gene promoted JK-SH007 biofilm formation, while an increase in the expression level of the ropN gene inhibited JK-SH007 biofilm formation. The possible mechanism by which JK-SH007 was inhibited by biofilm formation under natural culture was revealed. These results indicate the importance of adding nutrients to JK-SH007 biocides produced on a commercial scale. This is the first report of JK-SH007 producing a long-lasting biofilm that guarantees antagonism.}, } @article {pmid32048056, year = {2020}, author = {Pedroza-Dávila, U and Uribe-Alvarez, C and Morales-García, L and Espinoza-Simón, E and Méndez-Romero, O and Muhlia-Almazán, A and Chiquete-Félix, N and Uribe-Carvajal, S}, title = {Metabolism, ATP production and biofilm generation by Staphylococcus epidermidis in either respiratory or fermentative conditions.}, journal = {AMB Express}, volume = {10}, number = {1}, pages = {31}, pmid = {32048056}, issn = {2191-0855}, support = {IN203018//UNAM DGAPA PAPIIT/ ; }, abstract = {Staphylococcus epidermidis is a Gram-positive saprophytic bacterium found in the microaerobic/anaerobic layers of the skin that becomes a health hazard when it is carried across the skin through punctures or wounds. Pathogenicity is enhanced by the ability of S. epidermidis to associate into biofilms, where it avoids attacks by the host and antibiotics. To test the effect of oxygen on metabolism and biofilm generation, cells were cultured at different oxygen concentrations ([O2]). As [O2] decreased, S. epidermidis metabolism went from respiratory to fermentative. Remarkably, the rate of growth decreased at low [O2] while a high concentration of ATP ([ATP]) was kept. Under hypoxic conditions bacteria associated into biofilms. Aerobic activity sensitized the cell to hydrogen peroxide-mediated damage. In the presence of metabolic inhibitors, biofilm formation decreased. It is suggested that at low [O2] S. epidermidis limits its growth and develops the ability to form biofilms.}, } @article {pmid32046702, year = {2020}, author = {Alshahrani, AM and Gregory, RL}, title = {In vitro Cariostatic effects of cinnamon water extract on nicotine-induced Streptococcus mutans biofilm.}, journal = {BMC complementary medicine and therapies}, volume = {20}, number = {1}, pages = {45}, pmid = {32046702}, issn = {2662-7671}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cariostatic Agents/*pharmacology ; Cinnamomum zeylanicum/*chemistry ; Dental Caries/drug therapy/microbiology ; Microbial Sensitivity Tests ; Nicotine/adverse effects ; Plant Extracts/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {BACKGROUND: Dental caries is one of the most prevalent chronic oral diseases worldwide. Dental caries is mainly associated with Streptococcus mutans and the Lactobacillus species. A specific relationship was found between nicotine and S. mutans growth as the presence of nicotine increased S. mutans biofilm formation. Nicotine is able to increase the number of S. mutans and extracellular polysaccharide (EPS) synthesis. Among the widely used herbs and spices is cinnamon which demonstrated a strong antibacterial activity against a wide variety of bacteria including S. mutans and showed the ability to inhibit S. mutans biofilm formation. Cinnamon essential oil, obtained from the leaves of C. zeylanicum, has been demonstrated to be effective against S. mutans and Lactobacillus acidophilus, which are partially responsible for dental plaque formation and caries development. The aim of this study was to identify the effects of nicotine exposure on the inhibitory effects of cinnamon water extract on S. mutans biofilm formation.

MATERIALS AND METHODS: A 24-h culture of S. mutans UA159 in microtiter plates was treated with varying nicotine concentrations (0-32 mg/ml) in Tryptic Soy broth supplemented with 1% sucrose (TSBS) with or without a standardized concentration (2.5 mg/ml) of cinnamon water extract. A spectrophotometer was used to determine total growth absorbance and planktonic growth. The microtiter plate wells were washed, fixed and stained with crystal violet dye and the absorbance measured to determine biofilm formation.

RESULTS: The presence of 2.5 mg/ml cinnamon water extract inhibits nicotine-induced S. mutans biofilm formation from 34 to 98% at different concentrations of nicotine (0-32 mg/ml).

CONCLUSION: The results demonstrated nicotine-induced S. mutans biofilm formation is decreased from 34 to 98% in the presence of 2.5 mg/ml cinnamon water extract. This provides further evidence about the biofilm inhibitory properties of cinnamon water extract and reconfirms the harmful effects of nicotine.}, } @article {pmid32045645, year = {2020}, author = {Mirzaei, R and Mirzaei, H and Alikhani, MY and Sholeh, M and Arabestani, MR and Saidijam, M and Karampoor, S and Ahmadyousefi, Y and Moghadam, MS and Irajian, GR and Hasanvand, H and Yousefimashouf, R}, title = {Bacterial biofilm in colorectal cancer: What is the real mechanism of action?.}, journal = {Microbial pathogenesis}, volume = {142}, number = {}, pages = {104052}, doi = {10.1016/j.micpath.2020.104052}, pmid = {32045645}, issn = {1096-1208}, abstract = {Human colorectal cancer is the third most common cancer around the world. Colorectal cancer has various risk factors, but current works have bolded a significant activity for the microbiota of the human colon in the development of this disease. Bacterial biofilm has been mediated to non-malignant pathologies like inflammatory bowel disease but has not been fully documented in the setting of colorectal cancer. The investigation has currently found that bacterial biofilm is mediated to colon cancer in the human and linked to the location of human cancer, with almost all right-sided adenomas of colon cancers possessing bacterial biofilm, whilst left-sided cancer is rarely biofilm positive. The profound comprehension of the changes in colorectal cancer can provide interesting novel concepts for anticancer treatments. In this review, we will summarize and examine the new knowledge about the links between colorectal cancer and bacterial biofilm.}, } @article {pmid32044647, year = {2020}, author = {Wang, S and Ma, L and Xu, Y and Wang, Y and Zhu, N and Liu, J and Dolfing, J and Kerr, P and Wu, Y}, title = {The unexpected concentration-dependent response of periphytic biofilm during indole acetic acid removal.}, journal = {Bioresource technology}, volume = {303}, number = {}, pages = {122922}, doi = {10.1016/j.biortech.2020.122922}, pmid = {32044647}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; Biofilms ; *Ecosystem ; *Indoleacetic Acids ; Plant Growth Regulators ; }, abstract = {Due to its extensive application in agriculture as a germinating agent and growth promoter, indole acetic acid (IAA) is present in a variety of aquatic ecosystems. To explore the response of microbial aggregates to exogenous IAA in aquatic ecosystems, periphytic biofilm, a typical microbial aggregate, was exposed to IAA at different concentrations. Results reveal an unexpected concentration-dependent effect of IAA on periphytic biofilm. Concentrations of IAA less than 10 mg/L inhibit periphytic growth, but stimulate growth when the IAA concentration exceeds 50 mg/L. Periphytic biofilm adapts to different IAA concentrations by antioxidant enzyme activation, community structure optimization and carbon-metabolism pattern change, and promotes bioremediation of IAA contaminated water in the process. The removal rates of IAA reached up to 95%-100%. This study reveals the capacity of periphytic biofilm for IAA removal in practice.}, } @article {pmid32043899, year = {2020}, author = {Dávila-Aviña, J and Gil-Solís, C and Merino-Mascorro, J and García, S and Heredia, N}, title = {Phenolics with Bactericidal Activity Alter Motility and Biofilm Formation in Enterotoxigenic, Enteropathogenic, and Enterohemorrhagic Escherichia coli.}, journal = {Foodborne pathogens and disease}, volume = {17}, number = {9}, pages = {568-575}, doi = {10.1089/fpd.2019.2766}, pmid = {32043899}, issn = {1556-7125}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Enterohemorrhagic Escherichia coli/*drug effects ; Enteropathogenic Escherichia coli/*drug effects ; Enterotoxigenic Escherichia coli/*drug effects ; Escherichia coli Proteins/genetics ; Genes, Bacterial ; Microbial Sensitivity Tests ; Polyphenols/*pharmacology ; Virulence ; }, abstract = {Most Escherichia coli strains are innocuous to human beings; however, some strains can cause diarrhea and are grouped into pathotypes. Since current trends promote the use of natural-origin compounds to control bacteria, in this study, the effects of the phenolic compounds (PCs) tannic acid (TA), gallic acid (GA), methyl gallate (MG), and epigallocatechin gallate (EG) on the growth, swarming motility, biofilm formation, and expression of selected virulence genes of three E. coli pathotypes (enteropathogenic Escherichia coli [EPEC], enterohemorrhagic Escherichia coli [EHEC], and enterotoxigenic Escherichia coli [ETEC]) were evaluated. Minimum bactericidal concentrations (MBCs) were determined by using microtiter plates, and the effects of sublethal PC concentrations on swarming motility were evaluated on Luria-Bertani agar. Biofilm formation was assessed in microtiter plates via crystal violet staining, and the expression levels of genes involved in biofilm formation (flhC, fliA, fliC, and csgA) and swarming motility (csgD and cyaA) were evaluated via quantitative PCR. All PC were bactericidal with minimal bactericidal concentrations ranging from 0.07 to 2.1 mg/mL. At concentrations lower than the MBC, PCs decreased swarming motility (14.8-100%). GA reduced biofilm formation in all of the tested strains; however, TA, MG, and EG induced biofilm formation in some strains at specific concentrations. TA induced the overexpression of csgA, csgD, and cyaA, whereas the other PCs did not have any effects or reduced their expression levels. The PCs tested in this study showed potential to control E. coli strains belonging to the EHEC, ETEC, and EPEC pathotypes by affecting their growth, swarming motility, and virulence gene expression; however, proper concentrations must be used to avoid the induction of undesirable virulence factor genes.}, } @article {pmid32043412, year = {2020}, author = {Attanasio, V and Di Luca, M and Carozza, A and Severino, S and Pallotto, C and Capoluongo, N and Palmiero, G and Bernardo, M and Tascini, C}, title = {Clinical efficacy of amoxicillin/clavulanate plus cefditoren as de-escalation combination therapy for endocarditis due to strongly biofilm-forming Enterococcus faecalis.}, journal = {Infectious diseases (London, England)}, volume = {52}, number = {5}, pages = {376-379}, doi = {10.1080/23744235.2020.1725109}, pmid = {32043412}, issn = {2374-4243}, mesh = {Aged ; Amoxicillin-Potassium Clavulanate Combination/*therapeutic use ; Anti-Bacterial Agents/*therapeutic use ; Biofilms ; Cephalosporins/*therapeutic use ; Drug Therapy, Combination ; Endocarditis, Bacterial/*drug therapy ; Enterococcus faecalis/*drug effects/isolation & purification ; Female ; Humans ; Length of Stay ; Male ; Middle Aged ; Treatment Outcome ; }, } @article {pmid32043363, year = {2020}, author = {Bose, SK and Chauhan, M and Dhingra, N and Chhibber, S and Harjai, K}, title = {Terpinen-4-ol attenuates quorum sensing regulated virulence factors and biofilm formation in Pseudomonas aeruginosa.}, journal = {Future microbiology}, volume = {15}, number = {}, pages = {127-142}, doi = {10.2217/fmb-2019-0204}, pmid = {32043363}, issn = {1746-0921}, mesh = {Acyl-Butyrolactones/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Drug Synergism ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/*metabolism ; Quorum Sensing/drug effects ; Terpenes/*pharmacology ; Virulence/*drug effects ; Virulence Factors/genetics/metabolism ; }, abstract = {Aim: To investigate the effects of Terpinen-4-ol on quorum sensing (QS)-regulated biofilm formation and virulence factors production in Pseudomonas aeruginosa. Materials & methods: QS inhibition, molecular docking analysis and gene expression studies were performed to check attenuation effect of Terpinen-4-ol on virulence of P. aeruginosa. Production of various virulence factors and biofilm formation were studied at sub-MIC of Terpinen-4-ol alone and in combination with ciprofloxacin. Results: Terpinen-4-ol at sub-MIC exhibited QS inhibition and downregulated all key QS genes. Molecular docking analysis showed high binding affinities of Terpinen-4-ol with QS receptors. Terpinen-4-ol exhibited synergistic interaction with ciprofloxacin and further reduced production of all the virulence factors and biofilms formation. Conclusion: Terpinen-4-ol could be developed into antivirulence drug after its in vivo evaluation for treatment strategies.}, } @article {pmid32042258, year = {2020}, author = {Bukhari, SI and Aleanizy, FS}, title = {Association of OprF mutant and disturbance of biofilm and pyocyanin virulence in pseudomonas aeruginosa.}, journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society}, volume = {28}, number = {2}, pages = {196-200}, pmid = {32042258}, issn = {1319-0164}, abstract = {Outer membrane porin F (OprF) is a major structural membrane protein of Pseudomonas aeruginosa, a recognised human opportunistic pathogen which is correlated with severe hospital-acquired infections. This study investigating a multiphenotypic approach, based on the comparative study of a wild type strain of P. aeruginosa, its isogenic OprF mutant. Both P. aeruginosa PAO1 and OprF mutant strains were grown in same condition and cultures were subjected to further analysis by SDS PAGE, pyocyanin production and biofilm formation that was analyse using scanning electron microscopy. Based on biofilm formation essay and pyocyanin production, the study showed that OprF plays a dynamic role in P. aeruginosa virulence. The absence of OprF results in slow growth rate corresponded to elongated lag phase and reduced biofilm production also a significance reduction in the production of the quorum-sensing-dependent virulence factors pyocyanin. Accordingly, in the OprF mutant scanning electron microscope "SEM" images showed impaired cellular niche and detached cells when compared to regular attached P. aeruginosa wild type cells in the niche. Taken together, this study shows the contribution of OprF in P. aeruginosa virulence, at least partly through impairment of biofilm, cell to cell attachment in niche and pyocyanin production. This study show a vital link between OprF and virulence factor production, providing novel insights for its role in pathogenicity and future could provide the basis for the development of novel drug targets for antibiotics and vaccines.}, } @article {pmid32042100, year = {2020}, author = {Souza, JGS and Bertolini, M and Thompson, A and Mansfield, JM and Grassmann, AA and Maas, K and Caimano, MJ and Barao, VAR and Vickerman, MM and Dongari-Bagtzoglou, A}, title = {Role of glucosyltransferase R in biofilm interactions between Streptococcus oralis and Candida albicans.}, journal = {The ISME journal}, volume = {14}, number = {5}, pages = {1207-1222}, pmid = {32042100}, issn = {1751-7370}, support = {R21 AI128379/AI/NIAID NIH HHS/United States ; RO1 DE013986//U.S. Department of Health & Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/International ; RO1AI029735//U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/International ; R21AI126146//U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/International ; }, mesh = {Animals ; *Biofilms ; Candida albicans/genetics/*physiology ; Glucans ; Glucosyltransferases/*metabolism ; Glycogen Debranching Enzyme System ; Mice ; Streptococcus ; Streptococcus mutans/genetics ; Streptococcus oralis/genetics/*physiology ; }, abstract = {Streptococcal glucosyltransferases (Gtf) synthesize α-glucan exopolymers which contribute to biofilm matrix. Streptococcus oralis interacts with the opportunistic pathogen Candida albicans to form hypervirulent biofilms. S. oralis 34 has a single gtf gene (gtfR). However, the role of gtfR in single and mixed species biofilms with C. albicans has never been examined. A gtfR deletion mutant, purified GtfR, and recombinant GtfR glucan-binding domain were tested in single and mixed biofilms on different substrata in vitro. A mouse oral infection model was also used. We found that in single species biofilms growing with sucrose on abiotic surfaces S. oralis gtfR increased biofilm matrix, but not bacterial biomass. In biofilms with C. albicans, S. oralis encoding gtfR showed increased bacterial biomass on all surfaces. C. albicans had a positive effect on α-glucan synthesis, and α-glucans increased C. albicans accretion on abiotic surfaces. In single and mixed infection of mice receiving sucrose S. oralis gtfR enhanced mucosal burdens. However, sucrose had a negative impact on C. albicans burdens and reduced S. oralis burdens in co-infected mice. Our data provide new insights on the GtfR-mediated interactions between the two organisms and the influence of biofilm substratum and the mucosal environment on these interactions.}, } @article {pmid32041788, year = {2020}, author = {Gries, CM and Biddle, T and Bose, JL and Kielian, T and Lo, DD}, title = {Staphylococcus aureus Fibronectin Binding Protein A Mediates Biofilm Development and Infection.}, journal = {Infection and immunity}, volume = {88}, number = {5}, pages = {}, pmid = {32041788}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 AI063426/AI/NIAID NIH HHS/United States ; R01 AI121073/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*metabolism ; Animals ; Bacterial Adhesion/physiology ; Bacterial Proteins/*metabolism ; Biofilms/growth & development ; Humans ; Mice ; Mice, Inbred C57BL ; Protein Binding/physiology ; Staphylococcal Infections/*metabolism/*microbiology ; Staphylococcus aureus/*metabolism/*pathogenicity ; }, abstract = {Implanted medical device-associated infections pose significant health risks, as they are often the result of bacterial biofilm formation. Staphylococcus aureus is a leading cause of biofilm-associated infections which persist due to mechanisms of device surface adhesion, biofilm accumulation, and reprogramming of host innate immune responses. We found that the S. aureus fibronectin binding protein A (FnBPA) is required for normal biofilm development in mammalian serum and that the SaeRS two-component system is required for functional FnBPA activity in serum. Furthermore, serum-developed biofilms deficient in FnBPA were more susceptible to macrophage invasion, and in a model of biofilm-associated implant infection, we found that FnBPA is crucial for the establishment of infection. Together, these findings show that S. aureus FnBPA plays an important role in physical biofilm development and represents a potential therapeutic target for the prevention and treatment of device-associated infections.}, } @article {pmid32041059, year = {2020}, author = {Roy, D and McEvoy, J and Khan, E}, title = {Abundance and activity of ammonia oxidizing archaea and bacteria in bulk water and biofilm in water supply systems practicing chlorination and chloramination: Full and laboratory scale investigations.}, journal = {The Science of the total environment}, volume = {715}, number = {}, pages = {137043}, doi = {10.1016/j.scitotenv.2020.137043}, pmid = {32041059}, issn = {1879-1026}, mesh = {Ammonia ; *Archaea ; Bacteria ; *Biofilms ; Halogenation ; Nitrification ; Oxidation-Reduction ; Phylogeny ; Soil Microbiology ; Water ; Water Supply ; }, abstract = {The abundance and nitrification activity of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) in bulk water and biofilm in chloraminated and chlorinated water supply systems were investigated. The abundance of AOB varied between cold and warm periods while that was the case for AOA only in biofilm. Lower ammonia concentrations favored the abundance of AOA over AOB. AOA and AOB were found more in distal zones of the distribution system (DS). Higher numbers of AOA and AOB were observed in DS associated with chloramination compared to those associated with chlorination. Significant positive correlations between ammonia-N in bulk water and AOA indicate a possibility of involvement of AOA in nitrification in DS. A separate laboratory-based experiment simulating DS condition was conducted to understand the effects of chlorine and chloramine dosages and temperature on AOA and AOB. AOA were inhibited less than AOB in the presence of lower concentrations of chlorine and chloramine (1.5 and 2.0 mg/L chlorine; 0.05-0.1 and 0.3-0.4 mg/L chloramine) while both of them were not detected at higher dosages (2.5 mg/L chlorine and 1.5-1.6 mg/L chloramine). At a low temperature (10-12 °C), chloramine and chlorine provided similar inhibition trends in which AOB were inhibited more than AOA. At a high temperature (25 °C), chloramine was less inhibitory to AOA and AOB than chlorine.}, } @article {pmid32040901, year = {2019}, author = {Godovalov, AP and Stepanov, MS and Yakovlev, MV and Kobzarenko, EE and Batog, KA}, title = {[Determination of biofilm forming activity of microorganisms on synthetic polymeric materials.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {64}, number = {12}, pages = {758-761}, doi = {10.18821/0869-2084-2019-64-12-758-761}, pmid = {32040901}, issn = {0869-2084}, mesh = {*Biofilms ; Candida albicans/*growth & development ; Dental Cements ; Escherichia coli K12/*growth & development ; Glass Ionomer Cements ; Polyurethanes ; Polyvinyl Chloride ; Zinc Oxide ; }, abstract = {Microorganisms are able to form biofilms on surfaces of biotic and abiotic nature. In turn, in human biotopes there are optimal conditions for the implementation of biofilm-forming activity. Moreover, in medical practice, polymeric materials are often used for drainage or prosthetics, which can also be successfully colonized by bacteria. However, in laboratory practice, the formation of biofilms is usually evaluated on glass or polystyrene. The purpose of the study is to evaluate the methodological features of studying the biofilm-forming activity of microorganisms on the surface of synthetic polymeric materials. We used strains of Staphylococcus aureus ATCC 25923, Escherichia coli K-12, Candida albicans ATCC 10231, as well as synthetic polymeric materials - DentLight Flow light-curing composite material (nano-hybrid fluid composite; Russia), glass ionomer chemical curing Fuji 1 (Japan), cement for temporary fixation of orthopedic constructions TempBond NE (USA), acrylic, polyurethane and polyvinyl chloride. The formation of biofilms in flat-bottomed ELISA plates in this study was considered as a control group. If the polymer belonged to cold curing materials, sterile flat-bottomed tablets were used, the bottom of which was filled with a thin layer of plastic. After hardening of the plastic, biofilms were formed in the tablets. In the second series of experiments, hot cured materials cut into equal parts 5×5×1 mm in size were placed in the wells of a plate and again used to determine biofilm formation with subsequent coloring. To extract the dye, the pieces were transferred to a new plate to exclude the amount of film biomass formed on the walls of the plate wells. In both cases, cultivation was carried out at 37° C for 24-48 hours. The biomass of the film was stained with fuchsin. Statistical data processing was performed using t-Student criterion. For the threshold level of significance, the value p <0.05 was taken. It is established that the proposed options for determining biofilm forming ability are available and indicative. It was revealed that the same microorganisms have individual biofilm formation indicators for each polymer material. The light curing dental composite and polyvinyl chloride exhibit the more pronounced antiadhesive properties than cements and polyurethane. Up to date, most of the studies of biofilm formation have been carried out using glass or polystyrene, which, as a rule, are not used for the manufacture of prostheses, catheters, drains, etc., which makes it difficult to assess the true film-forming activity of microorganisms. The proposed methodological approaches, especially the second option for preparing testing samples, solve this problem. In general, the proposed approaches to testing biofilm-forming activity on polymers are very simple to implement and generally available. For an adequate study of the biofilms formation, it will be advisable to use polymer materials, directly used in medicine, rather than polystyrene tablets, the material of which is found exclusively in laboratory practice.}, } @article {pmid32039189, year = {2020}, author = {Hoseinzadeh, E and Wei, C and Farzadkia, M and Rezaee, A}, title = {Effects of Low Frequency-Low Voltage Alternating Electric Current on Apoptosis Progression in Bioelectrical Reactor Biofilm.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {2}, pmid = {32039189}, issn = {2296-4185}, abstract = {Bioelectrochemical systems have undergone several modifications to promote the enzymes or pathways used to reduce the energy required for microbial metabolism. Changes in dominant bacteria, population, and growth rates occur when an electric current is applied intermittently. Applying electricity to bioelectrical reactor (BER) biofilms can either stimulate cells or lead to cell death; therefore, determining the applied voltage range that leads to viable and stimulated bacteria is crucial. We investigated the progression of apoptosis induced by a low frequency-low voltage alternating electric current (AC) in a BER biofilm and found that biofilms on carbon cloth (CC) and stainless steel (SS) 304 electrodes had pHzpc values of 8.67. The pHzpc of the biofilms increased by two compared to that of the inoculant bacteria mass. Furthermore, the Henderson-Hasselbalch equation reveals that the compositions of cell walls of the biofilms that formed on the CC and SS304 electrodes are very similar. In contrast, the CC and SS304 biofilms differ from the inoculant biomass without the influence of an AC field; this indicates that there are differences in the compositions of the cell walls in the present bacteria. Fourier transform infrared spectroscopy was used to compare spectra of the biofilms with that of the inoculation mass, and there were differences in shape and absorbance intensity, indicating variability in the composition, and quantity of each individual biofilm component. In addition, the dehydrogenase activity (DHA) content varied under different applied voltages; the highest DHA was obtained at 8 Vpp. A flow cytometry analysis showed a relatively low number of apoptotic cells (10.93 ± 5.19%) for the AC amplitudes studied. Thus, a low voltage-low frequency AC likely induces significant changes in bacterial metabolic activity but causes no significant change in their viability.}, } @article {pmid32039129, year = {2019}, author = {Stapleton, EM and Manges, R and Parker, G and Stone, EA and Peters, TM and Blount, RJ and Noriega, J and Li, X and Zabner, J and Polgreen, PM and Chipara, O and Herman, T and Comellas, AP}, title = {Indoor Particulate Matter From Smoker Homes Induces Bacterial Growth, Biofilm Formation, and Impairs Airway Antimicrobial Activity. A Pilot Study.}, journal = {Frontiers in public health}, volume = {7}, number = {}, pages = {418}, pmid = {32039129}, issn = {2296-2565}, support = {P01 HL091842/HL/NHLBI NIH HHS/United States ; P30 ES005605/ES/NIEHS NIH HHS/United States ; U54 TR001356/TR/NCATS NIH HHS/United States ; }, abstract = {Background: Particulate matter (PM) air pollution causes deleterious health effects; however, less is known about health effects of indoor air particulate matter (IAP). Objective: To understand whether IAP influences distinct mechanisms in the development of respiratory tract infections, including bacterial growth, biofilm formation, and innate immunity. Additionally, we tested whether IAP from Iowa houses of subjects with and without recent respiratory exacerbations recapitulated the National Institute of Standards and Technology (NIST) IAP findings. Methods: To test the effect of NIST and Iowa IAP on bacterial growth and biofilm formation, we assessed Staphylococcus aureus growth and Pseudomonas aeruginosa biofilm formation with and without the presence of IAP. To assess the effect of IAP on innate immunity, we exposed primary human airway surface liquid (ASL) to NIST, and Iowa IAP. Lastly, we tested whether specific metals may be responsible for effects on airway innate immunity. Results: NIST and Iowa IAP significantly enhanced bacterial growth and biofilm formation. NIST IAP (whole particle and the soluble portion) impaired ASL antimicrobial activity. IAP from one Iowa home significantly impaired ASL antimicrobial activity (p < 0.05), and five other homes demonstrated a trend (p ≤ 0.18) of impaired ASL antimicrobial activity. IAP from homes of subjects with a recent history of respiratory exacerbation tended (p = 0.09) to impair ASL antimicrobial activity more than IAP from homes of those without a history respiratory exacerbation. Aluminum and Magnesium impaired ASL antimicrobial activity, while copper was bactericidal. Combining metals varied their effect on ASL antimicrobial activity. Conclusions: NIST IAP and Iowa IAP enhanced bacterial growth and biofilm formation. ASL antimicrobial activity was impaired by NIST IAP, and Iowa house IAP from subjects with recent respiratory exacerbation tended to impair ASL antimicrobial activity. Individual metals may explain impaired ASL antimicrobial activity; however, antimicrobial activity in the presence of multiple metals warrants further study.}, } @article {pmid32038604, year = {2020}, author = {Dahyot, S and Oxaran, V and Niepceron, M and Dupart, E and Legris, S and Destruel, L and Didi, J and Clamens, T and Lesouhaitier, O and Zerdoumi, Y and Flaman, JM and Pestel-Caron, M}, title = {Role of the LytSR Two-Component Regulatory System in Staphylococcus lugdunensis Biofilm Formation and Pathogenesis.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {39}, pmid = {32038604}, issn = {1664-302X}, abstract = {Staphylococcus lugdunensis is a coagulase negative Staphylococcus recognized as a virulent pathogen. It is responsible for a wide variety of infections, some of which are associated with biofilm production, such as implanted medical device infections or endocarditis. However, little is known about S. lugdunensis regulation of virulence factor expression. Two-component regulatory systems (TCS) play a critical role in bacterial adaptation, survival, and virulence. Among them, LytSR is widely conserved but has variable roles in different organisms, all connected to metabolism or cell death and lysis occurring during biofilm development. Therefore, we investigated here the functions of LytSR in S. lugdunensis pathogenesis. Deletion of lytSR in S. lugdunensis DSM 4804 strain did not alter either susceptibility to Triton X-100 induced autolysis or death induced by antibiotics targeting cell wall synthesis. Interestingly, ΔlytSR biofilm was characterized by a lower biomass, a lack of tower structures, and a higher rate of dead cells compared to the wild-type strain. Virulence toward Caenorhabditis elegans using a slow-killing assay was significantly reduced for the mutant compared to the wild-type strain. By contrast, the deletion of lytSR had no effect on the cytotoxicity of S. lugdunensis toward the human keratinocyte cell line HaCaT. Transcriptional analyses conducted at mid- and late-exponential phases showed that lytSR deletion affected the expression of 286 genes. Most of them were involved in basic functions such as the metabolism of amino acids, carbohydrates, and nucleotides. Furthermore, LytSR appeared to be involved in the regulation of genes encoding known or putative virulence and colonization factors, including the fibrinogen-binding protein Fbl, the major autolysin AtlL, and the type VII secretion system. Overall, our data suggest that the LytSR TCS is implicated in S. lugdunensis pathogenesis, through its involvement in biofilm formation and potentially by the control of genes encoding putative virulence factors.}, } @article {pmid32038515, year = {2019}, author = {Hegde, SR}, title = {Computational Identification of the Proteins Associated With Quorum Sensing and Biofilm Formation in Mycobacterium tuberculosis.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {3011}, pmid = {32038515}, issn = {1664-302X}, abstract = {With prolonged therapy and increased instances of drug resistance, tuberculosis is viewed as a serious infectious disease causing high mortality. Emerging concepts in Mycobacterium tuberculosis pathogenicity include biofilm formation, which endows bacterial survival in the host for a long time. To tackle chronic tuberculosis infection, a detailed understanding of the bacterial survival mechanisms is crucial. Using comparative genomics and literature mining, 115 M. tuberculosis proteins were shortlisted for their likely association with biofilm formation or quorum sensing. These include essential genes such as secA2, lpqY-sugABC, Rv1176c, and Rv0195, many of which are also known virulence factors. Furthermore, the functional relationship among these proteins was established by considering known protein-protein interactions, regulatory interactions, and gene expression correlation data/information. Graph centrality and motif analyses predicted the importance of proteins, such as Rv0081, DevR, RegX3, Rv0097, and Rv1996 in M. tuberculosis biofilm formation. Analysis of conservation across other biofilm-forming bacteria suggests that most of these genes are conserved in mycobacteria. As the processes, such as quorum sensing, leading to biofilm formation involve diverse pathways and interactions between proteins, these system-wide studies provide a novel perspective toward understanding mycobacterial persistence.}, } @article {pmid32037796, year = {2020}, author = {Liu, T and Khai Lim, Z and Chen, H and Hu, S and Yuan, Z and Guo, J}, title = {Temperature-Tolerated Mainstream Nitrogen Removal by Anammox and Nitrite/Nitrate-Dependent Anaerobic Methane Oxidation in a Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {54}, number = {5}, pages = {3012-3021}, doi = {10.1021/acs.est.9b05650}, pmid = {32037796}, issn = {1520-5851}, mesh = {*Ammonium Compounds ; Anaerobiosis ; Biofilms ; Bioreactors ; Denitrification ; *Methane ; Nitrites ; Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; Temperature ; }, abstract = {The mainstream anaerobic ammonium oxidation (anammox) process provides strong support to the on-going paradigm shift from energy-negative to energy-neutral in wastewater treatment plants. However, the low temperature (e.g., below 15 °C) represents one of the major challenges for mainstream anammox in practice. In this study, a stable nitrogen removal rate (0.13 kg m[-3] day[-1]), together with a high-level effluent quality (<5.0 mg N L[-1]), was achieved in a lab-scale upflow membrane biofilm reactor (MBfR) by coupling anammox with nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) microorganisms, at a temperature as low as 10 °C. With the temperature being progressively decreased from 25 to 10 °C, the total nitrogen removal efficiency was maintained in the range of 90-94% at a constant hydraulic retention time of 9 h. The impact of temperature on the biofilm system coupling anammox and n-DAMO reactions increased at a lower temperature range with higher Arrhenius coefficients. Additionally, 16S rRNA gene sequencing results showed that anammox bacteria, n-DAMO bacteria, and n-DAMO archaea jointly dominated the biofilm, and their respective abundances remained relatively stable when the temperature was decreased. The major reason for this temperature-tolerated performance is the overcapacity developed, which is indicated by biofilm thickness measurements and mathematical modeling. The stable performance obtained in this study shows promise for the n-DAMO application in domestic wastewater.}, } @article {pmid32037588, year = {2020}, author = {Wei, D and Zhao, XH}, title = {Calcium maintained higher quality and enhanced resistance against chilling stress by regulating enzymes in reactive oxygen and biofilm metabolism of Chinese winter jujube fruit.}, journal = {Journal of food biochemistry}, volume = {44}, number = {4}, pages = {e13161}, doi = {10.1111/jfbc.13161}, pmid = {32037588}, issn = {1745-4514}, mesh = {Biofilms ; Calcium ; China ; Fruit ; Oxygen ; *Ziziphus ; }, abstract = {The postharvest senescence of Chinese winter jujube fruit can be effectively delayed by refrigerated storage. However, chilling injury often occurs in jujube fruit during cold storage. In this study, Chinese winter jujubes were sprayed with CaCl2 (4%) 3 times at intervals of 2 hr on the day of refrigeration. The results presented that maximum difference of 2.7 N firmness, 3.42% TAC, and 0.8 OD280 /g polyphenol content were detected in calcium-treated fruit during cold storage, but the levels of O2- , MDA, hydrogen peroxide, browning rate, electrolyte leakage, and weight loss rate were significantly inhibited (p < .05). The maximum difference of enzymes activity of CAT, POD, SOD was 2.1, 10.8, and 40.6 mol h[-1] kg[-1] respectively, but 21.1 mol h[-1] kg[-1] PPO was restrained in the treated group. In conclusion, the results provided a reliable method for inhibiting cold injury and explained the internal molecular mechanism of the fruit regulated by calcium. PRACTICAL APPLICATIONS: Refrigerated storage is an important method for extending the storage time of Chinese winter jujube fruit. However, cold damage may occur when the jujubes are stored at low temperature for long-term. It is, therefore, of great significance to find a new method and reveal the molecular mechanism. We believe that our study makes a significant contribution to the literature because it provides an effective method of maintaining higher quality and mechanistic insights into the resistance against the chilling stress of jujubes.}, } @article {pmid32036742, year = {2021}, author = {Skariyachan, S and Gopal, D and Kadam, SP and Muddebihalkar, AG and Uttarkar, A and Niranjan, V}, title = {Carbon fullerene acts as potential lead molecule against prospective molecular targets of biofilm-producing multidrug-resistant Acinetobacter baumanni and Pseudomonas aerugenosa: computational modeling and MD simulation studies.}, journal = {Journal of biomolecular structure & dynamics}, volume = {39}, number = {3}, pages = {1121-1137}, doi = {10.1080/07391102.2020.1726821}, pmid = {32036742}, issn = {1538-0254}, mesh = {*Acinetobacter baumannii/genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms ; Carbon/pharmacology ; Drug Resistance, Multiple, Bacterial/genetics ; *Fullerenes/pharmacology ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Prospective Studies ; Pseudomonas ; }, abstract = {This study aimed to screen putative drug targets associated with biofilm formation of multidrug-resistant Acinetobacter baumannii and Pseudomonas areugenosa and prioritize carbon nano-fullerene as potential lead molecule by structure-based virtual screening. Based on the functional role, 36 and 83 genes that are involved in biofilm formation of A. baumannii and P. areugenosa respectively were selected and metabolic network was computationally constructed. The genes that lack three-dimensional structures were predicted and validated. Carbon nano-fullerene selected as lead molecule and their drug-likeliness and pharmacokinetics properties were computationally predicted. The binding potential of carbon nano-fullerene toward selected drug targets was modeled and compared with the binding of conventional drugs, doripenem, and polymyxin-B with their usual targets. The stabilities of four best-docked complexes were confirmed by molecular dynamic (MD) simulation. This study suggested that selected genes demonstrated relevant interactions in the constructed metabolic pathways. Carbon fullerene exhibited significant binding abilities to most of the prioritized targets in comparison with the binding of last-resort antibiotics and their usual target. The four best ligand-receptor interactions predicted by molecular docking revealed that stability throughout MD simulation. Notably, carbon fullerene exhibited profound binding with outer membrane protein (OmpA) and ribonuclease-HII (rnhB) of A. baumannii and 2-heptyl-4(1H)-quinolone synthase (pqsBC) and chemotaxis protein (wspA) of P. aeruginosa. Thus, the current study suggested that carbon fullerene was probably used as potential lead molecules toward selected targets of A. baumannii and P. aeruginosa and the applied aspects probably scaled up to design promising lead molecules toward these pathogens. Communicated by Ramaswamy H. Sarma.}, } @article {pmid32036275, year = {2020}, author = {Brescia, F and Marchetti-Deschmann, M and Musetti, R and Perazzolli, M and Pertot, I and Puopolo, G}, title = {The rhizosphere signature on the cell motility, biofilm formation and secondary metabolite production of a plant-associated Lysobacter strain.}, journal = {Microbiological research}, volume = {234}, number = {}, pages = {126424}, doi = {10.1016/j.micres.2020.126424}, pmid = {32036275}, issn = {1618-0623}, abstract = {Lysobacter spp. are common bacterial inhabitants of the rhizosphere of diverse plant species. However, the impact of the rhizosphere conditions on their physiology is still relatively understudied. To provide clues on the behaviour of Lysobacter spp. in this ecological niche, we investigated the physiology of L. capsici AZ78 (AZ78), a biocontrol strain isolated from tobacco rhizosphere, on a common synthetic growth medium (LBA) and on a growth medium containing components of the plant rhizosphere (RMA). The presence of a halo surrounding the AZ78 colony on RMA was a first visible effect related to differences in growth medium composition and it corresponded to the formation of a large outer ring. The lower quantity of nutrients available in RMA as compared with LBA was associated to a higher expression of a gene encoding cAMP-receptor-like protein (Clp), responsible for cell motility and biofilm formation regulation. AZ78 cells on RMA were motile, equipped with cell surface appendages and organised in small groups embedded in a dense layer of fibrils. Metabolic profiling by mass spectrometry imaging revealed increased diversity of analytes produced by AZ78 on RMA as compared with LBA. In particular, putative cyclic lipodepsipeptides, polycyclic tetramate macrolactams, cyclic macrolactams and other putative secondary metabolites with antibiotic activity were identified. Overall, the results obtained in this study shed a light on AZ78 potential to thrive in the rhizosphere by its ability to move, form biofilm and release secondary metabolites.}, } @article {pmid32034730, year = {2020}, author = {Benmouna, Z and Dalache, F and Zadi-Karam, H and Karam, NE and Vuotto, C}, title = {Ability of Three Lactic Acid Bacteria to Grow in Sessile Mode and to Inhibit Biofilm Formation of Pathogenic Bacteria.}, journal = {Advances in experimental medicine and biology}, volume = {1282}, number = {}, pages = {105-114}, doi = {10.1007/5584_2020_495}, pmid = {32034730}, issn = {0065-2598}, mesh = {*Bacterial Adhesion ; Bacteriocins/metabolism ; Biofilms/*growth & development ; Enterococcus/*growth & development/metabolism/*physiology ; Escherichia coli/*growth & development/pathogenicity ; Humans ; Staphylococcus aureus/*growth & development/pathogenicity ; Staphylococcus epidermidis/*growth & development/pathogenicity ; }, abstract = {In this study, we explored the effect of three lactic acid bacteria (LAB), i.e. Enterococcus sp CM9, Enterococcus sp CM18 and Enterococcus faecium H3, and their supernatants, on seven biofilm-forming pathogenic strains isolated from human urinary tract or nose infections. By quantitative biofilm production assay, a strong adherence ability of Enterococcus sp CM9 and Enterococcus sp CM18 was revealed while E. faecium H3 resulted to be moderately adherent. Inhibition tests demonstrated an antimicrobial activity of LAB against pathogens.The presence of cell free supernatant (CFS) of CM9 and CM18 strains significantly decreased the adhesion of S. aureus 10,850, S. epidermidis 4,296 and E. coli FSL24. The CFS of H3 strain was effective against S. epidermidis 4,296 and P. aeruginosa PA1FSL biofilms only. Biofilm formation of K. pneumoniae Kp20FSL, A. baumannii AB8FSL and ESBL+ E. coli FS101570 have not been affected by any CSF while P. aeruginosa PA1FSL biofilm increase in presence of CM9 and CM18 CFS.Confocal Laser Scanning Microscopy revealed that K. pneumoniae Kp20FSL biofilm was inhibited by Enterococcus sp CM9, when grown together.Our results suggest that the LAB strains and/or their bacteriocins can be considered as potential tools to control biofilm formation of some bacterial pathogens.}, } @article {pmid32034427, year = {2020}, author = {Röhner, E and Jacob, B and Böhle, S and Rohe, S and Löffler, B and Matziolis, G and Zippelius, T}, title = {Sodium hypochlorite is more effective than chlorhexidine for eradication of bacterial biofilm of staphylococci and Pseudomonas aeruginosa.}, journal = {Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA}, volume = {28}, number = {12}, pages = {3912-3918}, doi = {10.1007/s00167-020-05887-9}, pmid = {32034427}, issn = {1433-7347}, support = {S 01/17//Stiftung Endoprothetik/ ; }, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; Chondrocytes/drug effects/microbiology ; Humans ; Prosthesis-Related Infections/prevention & control ; Pseudomonas aeruginosa/*drug effects ; Sodium Hypochlorite/*pharmacology ; Staphylococcus aureus/*drug effects ; Staphylococcus epidermidis/*drug effects ; }, abstract = {PURPOSE: Periprosthetic infection is a common reason for surgical revision. Given the increasing resistance of bacteria to antibiotics (e.g., VRE, 4-MRGN) local antiseptic treatment is gaining in importance. However, no standard guideline-based treatment recommendation is yet available. The aim of this study was to investigate the effectiveness of sodium hypochlorite and chlorhexidine against bacterial biofilms. Furthermore, the toxicity of both antiseptics towards human chondrocytes was examined.

METHODS: Human chondrocytes were isolated, cultivated and treated with sodium hypochlorite and chlorhexidine. The viability of cultures was assessed by determination of cell count, XTT and MTT ELISAs, and fluorescent staining with propidium iodide. Bacterial strains of Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa were added to liquid media and incubated overnight. After determination of bacterial concentrations polyethylene (PE) devices were inoculated with bacteria for 48 h until biofilms formed. The devices were then washed, treated with antiseptics for 2 and 5 min and subsequently spread on agar plates.

RESULTS: Sodium hypochlorite is more effective than chlorhexidine in penetrating biofilms of S. aureus, S. epidermidis and P. aeruginosa. Both antiseptics are chondrotoxic, but sodium hypochlorite damages human chondrocytes less than chlorhexidine in vitro.

CONCLUSIONS: The findings confirm the effectiveness of sodium hypochlorite and chlorhexidine against bacterial biofilms. Both antiseptics can be recommended for the treatment of periprosthetic infections. The toxic effects of sodium hypochlorite and chlorhexidine towards chondrocytes may mean there is a risk of damage to cartilage tissue.

LEVEL OF EVIDENCE: Controlled experimental study.}, } @article {pmid32033878, year = {2020}, author = {Lawrence, JA and Huang, Z and Rathinavelu, S and Hu, JF and Garo, E and Ellis, M and Norman, VL and Buckle, R and Williams, RB and Starks, CM and Eldridge, GR}, title = {Optimized plant compound with potent anti-biofilm activity across gram-negative species.}, journal = {Bioorganic & medicinal chemistry}, volume = {28}, number = {5}, pages = {115229}, doi = {10.1016/j.bmc.2019.115229}, pmid = {32033878}, issn = {1464-3391}, mesh = {Amines/chemical synthesis/chemistry/*pharmacology ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Gram-Negative Bacteria/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {Many human diseases, including cystic fibrosis lung infections, are caused or exacerbated by bacterial biofilms. Specialized modes of motility, including swarming and twitching, allow gram-negative bacteria to spread across surfaces and form biofilms. Compounds that inhibit these motilities could slow the spread of biofilms, thereby allowing antibiotics to work better. We previously demonstrated that a set of plant-derived triterpenes, including oleanolic acid and ursolic acid, inhibit formation of Escherichia coli and Pseudomonas aeruginosa biofilms, and alter expression of genes involved in chemotaxis and motility. In the present study, we have prepared a series of analogs of oleanolic acid. The analogs were evaluated against clinical isolates of E. coli and P. aeruginosa in biofilm formation assays and swarming assays. From these analogs, compound 9 was selected as a lead compound for further development. Compound 9 inhibits E. coli biofilm formation at 4 µg/mL; it also inhibits swarming at ≤1 µg/mL across multiple clinical isolates of P. aeruginosa, E. coli, Burkholderia cepacia, and Salmonella enterica, and at <0.5 µg/mL against multiple agricultural strains. Compound 9 also potentiates the activity of the antibiotics tobramycin and colistin against swarming P. aeruginosa; this is notable, as tobramycin and colistin are inhaled antibiotics commonly used to treat P. aeruginosa lung infections in people with cystic fibrosis. qPCR experiments suggested that 9 alters expression of genes involved in regulating Type IV pili; western blots confirmed that expression of Type IV pili components PilA and PilY1 decreases in P. aeruginosa in the presence of 9.}, } @article {pmid32033530, year = {2020}, author = {Zheng, J and Wu, Y and Lin, Z and Wang, G and Jiang, S and Sun, X and Tu, H and Yu, Z and Qu, D}, title = {ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of Enterococcus faecalis.}, journal = {BMC microbiology}, volume = {20}, number = {1}, pages = {30}, pmid = {32033530}, issn = {1471-2180}, support = {SMGC201705029//Sanming Project of Medicine in Shenzhen/International ; JCYJ20170412143551332//Shenzhen Science and Technology Innovation Commission/International ; JCYJ20180302144431923//Shenzhen Science and Technology Innovation Commission/International ; JCYJ20180508162403996//Shenzhen Science and Technology Innovation Commission/International ; JCYJ20180302144721183//Shenzhen Science and Technology Innovation Commission/International ; 2019027//Shenzhen Nanshan District Scientific Research Program of the People's Republic of China/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Drug Resistance, Bacterial ; Endopeptidase Clp/*genetics/metabolism ; Enterococcus faecalis/*pathogenicity/physiology ; *Gene Deletion ; Linezolid/pharmacology ; Minocycline/pharmacology ; Proteomics/*methods ; Stress, Physiological ; Tandem Mass Spectrometry ; Virulence ; }, abstract = {BACKGROUND: ClpP is important for bacterial growth and plays an indispensable role in cellular protein quality control systems by refolding or degrading damaged proteins, but the physiological significance of ClpP in Enterococcus faecalis remains obscure. A clpP deletion mutant (△clpP) was constructed using the E. faecalis OG1RF strain to clarify the effect of ClpP on E. faecalis. The global abundance of proteins was determined by a mass spectrometer with tandem mass tag labeling.

RESULTS: The ΔclpP mutant strain showed impaired growth at 20 °C or 45 °C at 5% NaCl or 2 mM H2O2. The number of surviving ΔclpP mutants decreased after exposure to the high concentration (50× minimal inhibitory concentration) of linezolid or minocycline for 96 h. The ΔclpP mutant strain also demonstrated decreased biofilm formation but increased virulence in a Galleria mellonella model. The mass spectrometry proteomics data indicated that the abundances of 135 proteins changed (111 increased, 24 decreased) in the ΔclpP mutant strain. Among those, the abundances of stress response or virulence relating proteins: FsrA response regulator, gelatinase GelE, regulatory protein Spx (spxA), heat-inducible transcription repressor HrcA, transcriptional regulator CtsR, ATPase/chaperone ClpC, acetyl esterase/lipase, and chaperonin GroEL increased in the ΔclpP mutant strain; however, the abundances of ribosomal protein L4/L1 family protein (rplD), ribosomal protein L7/L12 (rplL2), 50S ribosomal protein L13 (rplM), L18 (rplR), L20 (rplT), 30S ribosomal protein S14 (rpsN2) and S18 (rpsR) all decreased. The abundances of biofilm formation-related adapter protein MecA increased, while the abundances of dihydroorotase (pyrC), orotate phosphoribosyltransferase (pyrE), and orotidine-5'-phosphate decarboxylase (pyrF) all decreased in the ΔclpP mutant strain.

CONCLUSION: The present study demonstrates that ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of E. faecalis.}, } @article {pmid32033480, year = {2020}, author = {Leonetti, S and Tuvo, B and Campanella, B and Legnaioli, S and Onor, M and Bramanti, E and Totaro, M and Baggiani, A and Giorgi, S and Privitera, GP and Piolanti, N and Parchi, PD and Casini, B}, title = {Evaluation of Microbial Adhesion and Biofilm Formation on Nano-Structured and Nano-Coated Ortho-Prosthetic Materials by a Dynamic Model.}, journal = {International journal of environmental research and public health}, volume = {17}, number = {3}, pages = {}, pmid = {32033480}, issn = {1660-4601}, mesh = {Acrylic Resins/administration & dosage/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Joint Prosthesis/*microbiology ; Metal Nanoparticles/*administration & dosage ; Silver/administration & dosage/*pharmacology ; }, abstract = {The bio-engineering technologies of medical devices through nano-structuring and coating was recently proposed to improve biocompatibility and to reduce microbial adhesion in the prevention of implantable device-related infections. Our aim was to evaluate the ability of new nano-structured and coated materials to prevent the adhesion and biofilm formation, according to the American Standard Test Method ASTM-E2647-13. The materials composition was determined by X-ray Fluorescence and Laser Induced Breakdown Spectroscopy. Silver release was evaluated by Inductively Coupled Plasma Mass Spectrometry analysis. The gene expression levels of the Quorum Sensing Las and Rhl system were evaluated by the ΔΔCt method. The Log bacterial density (Log CFU/cm[2]) on TiAl6V4 was 4.41 ± 0.76 and 4.63 ± 1.01 on TiAl6V4-AgNPs compared to 2.57 ± 0.70 on CoCr and 2.73 ± 0.61 on CoCr-AgNPs (P < 0.0001, A.N.O.V.A.- one way test). The silver release was found to be equal to 17.8 ± 0.2 µg/L after the batch phase and 1.3 ± 0.1 µg/L during continuous flow. The rhlR gene resulted in a 2.70-fold increased expression in biofilm growth on the silver nanoparticles (AgNPs) coating. In conclusion, CoCr showed a greater ability to reduce microbial adhesion, independently of the AgNPs coating. The silver release resulted in promoting the up-regulation of the Rhl system. Further investigation should be conducted to optimize the effectiveness of the coating.}, } @article {pmid32033098, year = {2020}, author = {Niu, TX and Wang, XN and Wu, HY and Bi, JR and Hao, HS and Hou, HM and Zhang, GL}, title = {Transcriptomic Analysis, Motility and Biofilm Formation Characteristics of Salmonella typhimurium Exposed to Benzyl Isothiocyanate Treatment.}, journal = {International journal of molecular sciences}, volume = {21}, number = {3}, pages = {}, pmid = {32033098}, issn = {1422-0067}, support = {No.2017YFC1600403//The National Key R and D Program of China/ ; 31571888//The National Natural Science Foundation of China/ ; 2019-MS-021//Liaoning Provincial Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Gene Expression Profiling/methods ; Isothiocyanates/*pharmacology ; Microbial Sensitivity Tests/methods ; Salmonella typhimurium/*drug effects/genetics ; Transcriptome/*drug effects/*genetics ; Virulence/drug effects/genetics ; Virulence Factors/genetics ; }, abstract = {Salmonella typhimurium (S. typhimurium) is a common foodborne pathogen that not only causes diseases and contaminates food, but also causes considerable economic losses. Therefore, it is necessary to find effective and feasible methods to control S. typhimurium. In this study, changes in S. typhimurium after treatment with benzyl isothiocyanate (BITC) were detected by transcriptomics to explore the antibacterial effect of BITC at subinhibitory concentration. The results showed that, in contrast to the control group (SC), the BITC-treated group (SQ_BITC) had 197 differentially expressed genes (DEGs), of which 115 were downregulated and 82 were upregulated. We screened out eight significantly downregulated virulence-related genes and verified gene expression by quantitative Real-time Polymerase Chain Reaction (qRT-PCR). We also selected motility and biofilm formation to observe the effects of BITC on the other virulence related factors of S. typhimurium. The results showed that both swimming and swarming were significantly inhibited. BITC also had a significant inhibitory effect on biofilm formation, and showed an effect on bacterial morphology. These results will be helpful for understanding the mechanism of the antibacterial action of BITC against S. typhimurium and other foodborne pathogens.}, } @article {pmid32032989, year = {2020}, author = {Anticó, E and Fontàs, C and Vera, R and Mostazo, G and Salvadó, V and Guasch, H}, title = {A novel Cyphos IL 104-based polymer inclusion membrane (PIM) probe to mimic biofilm zinc accumulation.}, journal = {The Science of the total environment}, volume = {715}, number = {}, pages = {136938}, doi = {10.1016/j.scitotenv.2020.136938}, pmid = {32032989}, issn = {1879-1026}, mesh = {*Biofilms ; Environmental Monitoring ; Polymers ; Rivers ; Water Pollutants, Chemical ; Zinc ; }, abstract = {The presence of Zn in surface waters from abandoned mining zones is a critical issue since excess Zn concentrations may affect aquatic life and whole ecosystems. We present, for the first time, a simple tool based on a polymer inclusion membrane (PIM) intended to monitor Zn in river water by mimicking metal accumulation in the biofilm. The PIM-based probe contains a polymeric membrane prepared using cellulose triacetate (CTA, 50% w/w) as the base polymer, nitrophenyloctyl ether (NPOE) as the plasticizer (20% w/w), and the ionic liquid (IL) Cyphos 104 as the extractant (30% w/w). The accumulation of Zn in the acceptor phase (0.01 M HNO3) was evaluated for different free metal concentrations at 4 h accumulation time resulting in a good correlation between the free metal concentration and the accumulated one. We also found that the metal accumulated agrees with the free metal fraction upon addition of EDTA in the donor solution. The results for Zn accumulation with the PIM-based probe were found to be comparable to those obtained for a biofilm that was grown in a stream from an abandoned mine area and subsequently translocated to the laboratory and put in contact with Zn polluted stream water, so confirming the effectiveness of this new probe in mimicking Zn accumulation in the biofilm.}, } @article {pmid32032938, year = {2020}, author = {Hong, P and Wu, X and Shu, Y and Wang, C and Tian, C and Wu, H and Xiao, B}, title = {Bioaugmentation treatment of nitrogen-rich wastewater with a denitrifier with biofilm-formation and nitrogen-removal capacities in a sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {303}, number = {}, pages = {122905}, doi = {10.1016/j.biortech.2020.122905}, pmid = {32032938}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {A strain with efficient biofilm-formation and aerobic denitrification capabilities was isolated and identified as Pseudomonas mendocina IHB602. In pure culture, strain IHB602 removed almost all NO3[-]-N, NO2[-]-N, and NH4[+]-N (initial concentrations 50 mg/L) within 24 h. The strain produced large amounts of extracellular polymeric substances (maximum 430.33 mg/g cell dry weight) rich in protein but containing almost no humic acid. This, and strong autoaggregation (maximum 47.09%) and hydrophobicity (maximum 85.07%), imparted strain IHB602 with biofilm forming traits. A sequencing batch biofilm reactor bioaugmented with strain IHB602 (SBBR1) had more rapid biofilm-formation than the control without strain IHB602 inoculation (SBBR2). During the stabilization period, the effluent removal ratios for NH4[+]-N (95%), NO3[-]-N (91%) and TN (88%) in SBBR1 were significantly higher than those in SBBR2 (NH4[+]-N: 91%, NO3[-]-N: 88%, TN: 82%). Microbial community structure analysis revealed that strain IHB602 successfully proliferated and contributed to nitrogen removal as well as biofilm formation.}, } @article {pmid32032775, year = {2020}, author = {Liu, T and Guo, J and Hu, S and Yuan, Z}, title = {Model-based investigation of membrane biofilm reactors coupling anammox with nitrite/nitrate-dependent anaerobic methane oxidation.}, journal = {Environment international}, volume = {137}, number = {}, pages = {105501}, doi = {10.1016/j.envint.2020.105501}, pmid = {32032775}, issn = {1873-6750}, mesh = {Anaerobiosis ; *Biofilms ; Bioreactors ; Denitrification ; *Methane/chemistry ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; }, abstract = {An innovative process coupling anaerobic ammonium oxidation (anammox) with nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) in membrane biofilm reactors (MBfRs) has been developed to achieve high-level nitrogen removal from both sidestream (i.e., anaerobic digestion liquor) and mainstream (i.e., domestic strength) wastewater. In this study, a 1D biofilm model embedding the n-DAMO and anammox reactions was developed to facilitate further understanding of the process and its optimization. The model was calibrated and validated using comprehensive data sets from two independent MBfRs, treating sidestream- and mainstream-strength wastewater, respectively. Modelling results revealed a unique biofilm stratification. While anammox bacteria dominated throughout the biofilm, n-DAMO archaea (coupling nitrate reduction with anaerobic methane oxidation) only occurred at the inner layer and n-DAMO bacteria (coupling nitrite reduction with anaerobic methane oxidation) spread more evenly with a slightly higher fraction in the outer layer. The established MBfRs were robust against dynamic influent flowrates and nitrite/ammonium ratios. Thicker biofilms were beneficial for not only the total nitrogen (TN) removal but also the system robustness. Additionally, a positive correlation between the nitrogen removal efficiency and the residual methane emission was observed, as a result of higher methane partial pressure required. However, there was a threshold of methane partial pressure, above which the residual methane increased but nitrogen removal efficiency was stable. Meanwhile, thicker biofilms were also favorable to achieve less residual methane emission. Simulation results also suggested the feasibility of methane-based MBfRs to polish mainstream anammox effluent to meet a stringent N discharge standard (e.g., TN < 5 mg/L).}, } @article {pmid32032766, year = {2020}, author = {Chen, L and Gu, L and Geng, X and Xu, G and Huang, X and Zhu, X}, title = {A novel cis antisense RNA AsfD promotes Salmonella enterica serovar Typhi motility and biofilm formation.}, journal = {Microbial pathogenesis}, volume = {142}, number = {}, pages = {104044}, doi = {10.1016/j.micpath.2020.104044}, pmid = {32032766}, issn = {1096-1208}, abstract = {Bacterial non-coding RNAs (ncRNAs) can participate in multiple biological processes, including motility, biofilm formation, and virulence. Using high-throughput sequencing and transcriptome analysis of Salmonella enterica serovar Typhi (S. Typhi), we identified a novel antisense RNA located at the opposite strand of the flhDC operon. In this study, a northern blot and qRT-PCR were used to confirm the expression of this newfound antisense RNA in S. Typhi. Moreover, 5' RACE and 3' RT-PCR were performed to reveal the molecular characteristics of the antisense RNA, which was 2079 nt - 2179 nt in length, covered the entire flhDC operon sequence, and termed AsfD. The level of AsfD expression was higher during the stationary phase of S. Typhi and activated by the regulators, OmpR and Fis. When AsfD was overexpressed, the level of flagellar gene flhDC transcription increased; moreover, the level of fliA and fljB expression, as well as the motility and biofilm formation of S. Typhi were also enhanced. The results of this study suggest that AsfD is likely to enhance the motility and biofilm formation of S. Typhi by up-regulating flhDC expression.}, } @article {pmid32029764, year = {2020}, author = {Ahmad, I and Nygren, E and Khalid, F and Myint, SL and Uhlin, BE}, title = {A Cyclic-di-GMP signalling network regulates biofilm formation and surface associated motility of Acinetobacter baumannii 17978.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {1991}, pmid = {32029764}, issn = {2045-2322}, mesh = {Acinetobacter baumannii/pathogenicity/*physiology ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cloning, Molecular ; Computational Biology ; Cyclic GMP/*analogs & derivatives/metabolism ; Fimbriae, Bacterial/metabolism ; Gene Expression Regulation, Bacterial ; Humans ; Opportunistic Infections/*microbiology ; Recombinant Proteins/genetics/metabolism ; Salmonella typhimurium/genetics/metabolism ; Signal Transduction/physiology ; Vibrio cholerae/genetics/metabolism ; }, abstract = {Acinetobacter baumannii has emerged as an increasing multidrug-resistant threat in hospitals and a common opportunistic nosocomial pathogen worldwide. However, molecular details of the pathogenesis and physiology of this bacterium largely remain to be elucidated. Here we identify and characterize the c-di-GMP signalling network and assess its role in biofilm formation and surface associated motility. Bioinformatic analysis revealed eleven candidate genes for c-di-GMP metabolizing proteins (GGDEF/EAL domain proteins) in the genome of A. baumannii strain 17978. Enzymatic activity of the encoded proteins was assessed by molecular cloning and expression in the model organisms Salmonella typhimurium and Vibrio cholerae. Ten of the eleven GGDEF/EAL proteins altered the rdar morphotype of S. typhimurium and the rugose morphotype of V. cholerae. The over expression of three GGDEF proteins exerted a pronounced effect on colony formation of A. baumannii on Congo Red agar plates. Distinct panels of GGDEF/EAL proteins were found to alter biofilm formation and surface associated motility of A. baumannii upon over expression. The GGDEF protein A1S_3296 appeared as a major diguanylate cyclase regulating macro-colony formation, biofilm formation and the surface associated motility. AIS_3296 promotes Csu pili mediated biofilm formation. We conclude that a functional c-di-GMP signalling network in A. baumannii regulates biofilm formation and surface associated motility of this increasingly important opportunistic bacterial pathogen.}, } @article {pmid32029738, year = {2019}, author = {Vermilyea, DM and Ottenberg, GK and Davey, ME}, title = {Citrullination mediated by PPAD constrains biofilm formation in P. gingivalis strain 381.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {7}, pmid = {32029738}, issn = {2055-5008}, support = {T90 DE021990/DE/NIDCR NIH HHS/United States ; F31DE027278//U.S. Department of Health & Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/International ; R01DE019117//U.S. Department of Health & Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/International ; F31 DE027278/DE/NIDCR NIH HHS/United States ; R01DEO24580//U.S. Department of Health & Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/International ; R01 DE019117/DE/NIDCR NIH HHS/United States ; R01 DE024580/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/metabolism ; Arginine/metabolism ; Biofilms/*growth & development ; *Citrullination ; Citrulline/metabolism ; Gene Deletion ; Porphyromonas gingivalis/enzymology/*genetics/*physiology ; Protein-Arginine Deiminases/genetics/metabolism ; }, abstract = {Porphyromonas gingivalis is the only known human-associated prokaryote that produces a peptidylarginine deiminase (PPAD), a protein-modifying enzyme that is secreted along with a number of virulence factors via a type IX secretion system (T9SS). While the function of PPAD in P. gingivalis physiology is not clear, human peptidylarginine deiminases are known to convert positively charged arginine residues within proteins to neutral citrulline and, thereby, impact protein conformation and function. Here, we report that the lack of citrullination in a PPAD deletion mutant (Δ8820) enhances biofilm formation. More Δ8820 cells attached to the surface than the parent strain during the early stages of biofilm development and, ultimately, mature Δ8820 biofilms were comprised of significantly more cell-cell aggregates and extracellular matrix. Imaging by electron microscopy discovered that Δ8820 biofilm cells secrete copious amounts of protein aggregates. Furthermore, gingipain-derived adhesin proteins, which are also secreted by the T9SS were predicted by mass spectrometry to be citrullinated and citrullination of these targets by wild-type strain 381 in vitro was confirmed. Lastly, Δ8820 biofilms contained more gingipain-derived adhesin proteins and more gingipain activity than 381 biofilms. Overall, our findings support the model that citrullination of T9SS cargo proteins known to play a key role in colonization, such as gingipain-derived adhesin proteins, is an underlying mechanism that modulates P. gingivalis biofilm development.}, } @article {pmid32029309, year = {2020}, author = {Burneo, BS and Juárez, AS and Nieto-Monteros, DA}, title = {Un-steady state modeling for free cyanide removal and biofilm growth in a RBC batch process.}, journal = {Journal of hazardous materials}, volume = {388}, number = {}, pages = {120647}, doi = {10.1016/j.jhazmat.2019.05.040}, pmid = {32029309}, issn = {1873-3336}, mesh = {Bacillus/*growth & development ; Biofilms/*growth & development ; Biomass ; Bioreactors/*microbiology ; Cyanides/*analysis ; Gold ; Mining ; Models, Theoretical ; Water Pollutants, Chemical/*analysis ; Water Purification/*methods ; }, abstract = {Biofilm growth and free cyanide biological removal from gold mine wastewater were modeled and simulated using a bench-scale rotating biological contactor (RBC). Eight batch cultures were run in three independent compartments (1.7 L, each) of the RBC. The system worked under the following conditions: [CNi[-]] = 0.3 g/L, pH = 10.5 ± 0.5, T = 20 ± 5 °C, ω =5 rpm, and 40.5 % of disc submersion. During each culture, biofilm thickness, biomass, and free cyanide concentration in the liquid were quantified. Subsequently, μmax, [Formula: see text] , [Formula: see text] were determined using experimental data to later model and simulate the biofilm thickness and free cyanide biological removal with Wolfram Mathematica software. After the experiments, free cyanide biological removal was 96.33 % after three days, and maximum biofilm thickness was 0.0292 cm in the 16th day. Moreover, biofilm growth and free cyanide consumption models were adjusted to the experimental data with r[2] = 0.90 and r[2] = 0.99. Also, there was an equivalent error of 7.89 and 7.38 and a standard deviation of 10.89 % and 10.17 %, between the models and their experimental data, respectively. Finally, the proposed models will allow improvement of reactor operation and its design.}, } @article {pmid32028684, year = {2020}, author = {Vestby, LK and Grønseth, T and Simm, R and Nesse, LL}, title = {Bacterial Biofilm and its Role in the Pathogenesis of Disease.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {2}, pages = {}, pmid = {32028684}, issn = {2079-6382}, abstract = {Recognition of the fact that bacterial biofilm may play a role in the pathogenesis of disease has led to an increased focus on identifying diseases that may be biofilm-related. Biofilm infections are typically chronic in nature, as biofilm-residing bacteria can be resilient to both the immune system, antibiotics, and other treatments. This is a comprehensive review describing biofilm diseases in the auditory, the cardiovascular, the digestive, the integumentary, the reproductive, the respiratory, and the urinary system. In most cases reviewed, the biofilms were identified through various imaging technics, in addition to other study approaches. The current knowledge on how biofilm may contribute to the pathogenesis of disease indicates a number of different mechanisms. This spans from biofilm being a mere reservoir of pathogenic bacteria, to playing a more active role, e.g., by contributing to inflammation. Observations also indicate that biofilm does not exclusively occur extracellularly, but may also be formed inside living cells. Furthermore, the presence of biofilm may contribute to development of cancer. In conclusion, this review shows that biofilm is part of many, probably most chronic infections. This is important knowledge for development of effective treatment strategies for such infections.}, } @article {pmid32028622, year = {2020}, author = {Nett, JE and Andes, DR}, title = {Contributions of the Biofilm Matrix to Candida Pathogenesis.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {6}, number = {1}, pages = {}, pmid = {32028622}, issn = {2309-608X}, support = {2017074/DDCF_/Doris Duke Charitable Foundation/United States ; K08 AI108727/AI/NIAID NIH HHS/United States ; K08 AI108727/NH/NIH HHS/United States ; 112580130/DDCF/Doris Duke Charitable Foundation/United States ; R01AI073289/NH/NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; }, abstract = {In healthcare settings, Candida spp. cause invasive disease with high mortality. The overwhelming majority of cases are associated with the use of critically-needed medical devices, such as vascular catheters. On the surface of these indwelling materials, Candida forms resilient, adherent biofilm communities. A hallmark characteristic of this process is the production of an extracellular matrix, which promotes fungal adhesion and provides protection from external threats. In this review, we highlight the medical relevance of device-associated Candida biofilms and draw attention to the process of Candida-biofilm-matrix production. We provide an update on the current understanding of how biofilm extracellular matrix contributes to pathogenicity, particularly through its roles in the promoting antifungal drug tolerance and immune evasion.}, } @article {pmid32026679, year = {2020}, author = {Barlow, DE and Biffinger, JC and Estrella, L and Lu, Q and Hung, CS and Nadeau, LJ and Crouch, AL and Russell, JN and Crookes-Goodson, WJ}, title = {Edge-Localized Biodeterioration and Secondary Microplastic Formation by Papiliotrema laurentii Unsaturated Biofilm Cells on Polyurethane Films.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {36}, number = {6}, pages = {1596-1607}, doi = {10.1021/acs.langmuir.9b03421}, pmid = {32026679}, issn = {1520-5827}, mesh = {Basidiomycota ; Biofilms ; *Microplastics ; Plastics ; *Polyurethanes ; }, abstract = {Painted environmental surfaces are prone to microbiological colonization with potential coating deterioration induced by the microorganisms. Accurate mechanistic models of these interactions require an understanding of the heterogeneity in which the deterioration processes proceed. Here, unsaturated biofilms (i.e., at air/solid interfaces) of the yeast Papiliotrema laurentii were prepared on polyether polyurethane (PEUR) and polyester-polyether polyurethane (PEST-PEUR) coatings and incubated for up to 33 days at controlled temperature and humidity with no additional nutrients. Transmission micro-Fourier transform infrared microscopy (μFTIR) confirmed preferential hydrolysis of the ester component by the biofilm. Atomic force microscopy combined with infrared nanospectroscopy (AFM-IR) was used to analyze initial PEST-PEUR coating deterioration processes at the single-cell level, including underlying surfaces that became exposed following cell translocation. The results revealed distinct deterioration features that remained localized within ∼10 μm or less of the edges of individual cells and cell clusters. These features comprised depressions of up to ∼300 nm with locally reduced ester/urethane ratios. They are consistent with a formation process initiated by enzymatic ester hydrolysis followed by erosion from water condensation cycles. Further observations included particle accumulation in the broader biofilm vicinity. AFM-IR spectroscopy indicated these to be secondary microplastics consisting of urethane-rich oligomeric aggregates. Overall, multiple contributing factors have been identified that can facilitate differential deterioration rates across the PEST-PEUR surface. Effects of the imposed nutrient conditions on Papiliotrema laurentii physiology were also apparent, with cells developing the characteristics of starvation response, despite the availability of polyester metabolites as a carbon source. The combined results provide new laboratory insights into field-relevant microbiological polymer deterioration mechanisms and biofilm physiology at polymer coating interfaces.}, } @article {pmid32023892, year = {2020}, author = {de Oliveira, RVD and Bonafé, FSS and Spolidorio, DMP and Koga-Ito, CY and Farias, AL and Kirker, KR and James, GA and Brighenti, FL}, title = {Streptococcus mutans and Actinomyces naeslundii Interaction in Dual-Species Biofilm.}, journal = {Microorganisms}, volume = {8}, number = {2}, pages = {}, pmid = {32023892}, issn = {2076-2607}, support = {2012/17236-4, 2013/12326-8, 2014/16935-1, 2014/02397-8 and 2015/07679-4//São Paulo Research Foundation (FAPESP)/ ; Finance Code 001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES)/ ; }, abstract = {The study of bacterial interaction between Streptococcus mutans and Actinomyces naeslundii may disclose important features of biofilm interspecies relationships. The aim of this study was to characterize-with an emphasis on biofilm formation and composition and metabolic activity-single- and dual-species biofilms of S. mutans or A. naeslundii, and to use a drip flow reactor (DFR) to evaluate biofilm stress responses to 0.2% chlorhexidine diacetate (CHX). Single- and dual-species biofilms were grown for 24 h. The following factors were evaluated: cell viability, biomass and total proteins in the extracellular matrix, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide-"XTT"-reduction and lactic acid production. To evaluate stress response, biofilms were grown in DFR. Biofilms were treated with CHX or 0.9% sodium chloride (NaCl; control). Biofilms were plated for viability assessment. Confocal laser-scanning microscopy (CLSM) was also performed. Data analysis was carried out at 5% significance level. S. mutans viability and lactic acid production in dual-species biofilms were significantly reduced. S. mutans showed a higher resistance to CHX in dual-species biofilms. Total protein content, biomass and XTT reduction showed no significant differences between single- and dual-species biofilms. CLSM images showed the formation of large clusters in dual-species biofilms. In conclusion, dual-species biofilms reduced S. mutans viability and lactic acid production and increased S. mutans' resistance to chlorhexidine.}, } @article {pmid32023715, year = {2020}, author = {Guo, HN and Chen, Z and Xiang, J}, title = {[Influence of abaR gene knockout on growth metabolism and biofilm formation of Acinetobacter baumannii].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {36}, number = {1}, pages = {32-36}, doi = {10.3760/cma.j.issn.1009-2587.2020.01.006}, pmid = {32023715}, issn = {1009-2587}, support = {16ZR1420800//Natural Science Foundation of Shanghai Municipal Science and Technology Commission/ ; }, mesh = {*Acinetobacter baumannii ; Anti-Bacterial Agents ; *Biofilms ; Gene Knockout Techniques ; Polymerase Chain Reaction ; }, abstract = {Objective: To investigate the influence of abaR gene knockout on growth metabolism and biofilm formation of Acinetobacter baumannii. Methods: The abaR gene was knocked out from Acinetobacter baumannii standard strain ATCC 17978 (wild strain) by homologous recombination method, and then the ATCC 17978 abaR knockout strain (ATCC 17978/ΔabaR: : Kn) was obtained and verified by polymerase chain reaction (PCR) electrophoresis and sequencing. The growth curves of Acinetobacter baumannii wild strain and Acinetobacter baumannii knockout strain were determined by microplate reader within cultivation hour (CH) 18, and the biofilm formation ability was measured by crystal violet staining at CH 8, 24, and 48, respectively. The sample number at each time point was 3.The results were denoted as absorbance value. Data were processed with analysis of variance of factorial design, one-way analysis of variance, t test, and least-significant difference test. Results: (1) The length of PCR product of target fragment ΔabaR: : Kn was 3 029 bp. The abaR gene was knocked out to obtain the knockout strain ATCC 17978/ΔabaR: : Kn. The length of PCR product of the knockout strain was 3 300 bp. The abaR gene was successfully knocked out. (2) At CH 2, 3, and 4, the absorbance values of Acinetobacter baumannii wild strain were slightly higher than those of the knockout strain. The absorbance values of Acinetobacter baumannii wild strain and knockout strain were similar from CH 5 to 18. (3) At CH 8 and 24, the biofilm formation ability of Acinetobacter baumannii wild strains (0.644±0.066, 0.574±0.184) was similar to that of knockout strains (0.559±0.008, 0.394±0.030, t=2.209, 1.167, P>0.05). At CH 48, the biofilm formation ability of Acinetobacter baumannii wild strains (1.157±0.259) was significantly stronger than that of Acinetobacter baumannii knockout strains (0.576±0.026, t=3.865, P<0.05). The biofilm formation ability of Acinetobacter baumannii wild strains at CH 48 was significantly stronger than that at CH 8 and 24 (P<0.05). The biofilm formation ability of Acinetobacter baumannii knockout strains at CH 24 was significantly weaker than that at CH 8 and 48 (P<0.05). Conclusions: The abaR gene of Acinetobacter baumannii ATCC 17978 can be successfully knocked out by homologous recombination to obtain its knockout strain ATCC 17978/ΔabaR: : Kn. The abaR gene does not affect the growth and metabolism of Acinetobacter baumanniibut can weaken its biofilm formation ability.}, } @article {pmid32023713, year = {2020}, author = {Qi, ZY and Yang, SY and Dong, SW and Zhao, FF and Qin, JH and Xiang, J}, title = {[Biological characteristics and genomic information of a bacteriophage against pan-drug resistant Klebsiella pneumoniae in a burn patient and its effects on bacterial biofilm].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {36}, number = {1}, pages = {14-23}, doi = {10.3760/cma.j.issn.1009-2587.2020.01.004}, pmid = {32023713}, issn = {1009-2587}, support = {16ZR1420800//Natural Science Foundation of Shanghai Science and Technology Commission/ ; }, mesh = {*Bacteriophages ; Biofilms ; *Burns ; China ; Genomics ; Humans ; Klebsiella pneumoniae ; }, abstract = {Objective: To isolate a bacteriophage against pan-drug resistant Klebsiella pneumoniae in a burn patient, and to study its biological characteristics, genomic information, and effects on bacterial biofilm. Methods: (1) In 2018, pan-drug resistant Klebsiella pneumoniae UA168 (hereinafter referred to as the host bacteria) solution isolated from the blood of a burn patient in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (hereinafter referred to as Ruijin Hospital) was used to isolate and purify the bacteriophage against pan-drug resistant Klebsiella pneumoniae from the sewage of Ruijin Hospital with sewage co-culture method, drip plate method, and double-agar plate method. The bacteriophage was named as phage KP168 and the plaque morphology was observed. (2) The phage KP168 solution was taken for cesium chloride density gradient centrifugation and dialysis, and then the morphology of phage KP168 was observed through transmission electron microscope after phosphotungstic acid negative staining. (3) The phage KP168 solution was taken to determine the lytic ability of the phage KP168 against 20 strains of pan-drug resistant Klebsiella pneumoniae isolated from the burned patients' blood in Ruijin Hospital by the drip plate method, and then the lysis rate was calculated. (4) The phage KP168 solution at a initial titer of 9.3×10(11) plaque-forming unit (PFU)/mL (400 μL per tube) and the host bacteria solution at a concentration of 1×10(9) colony-forming unit (CFU)/mL (4 mL per tube) were conventionally shaking cultured together for 4 hours at multiplicity of infection (MOI) of 10.000, 1.000, 0.100, 0.010, or 0.001, respectively (1 tube per MOI). The titer of phage KP168 was measured by the double-agar plate method (the measurement method was the same below) to select the optimal MOI. The experiment was repeated three times. (5) The host bacteria solution at a concentration of 1×10(9) CFU/mL (4 mL per tube) and the phage KP168 solution at an adjusted titer of 5×10(7) PFU/mL (400 μL per tube) were mixed at the MOI of 0.005. The plaques were counted 0 (immediately), 1, 2, 3, 4, 5, 15, and 30 minutes (1 tube at each time point) after mixing by the double-agar plate method (the counting method was the same below), and the percentage of adsorbed phages was calculated to screen for the optimal adsorption time. The experiment was repeated three times. (6) The host bacteria solution at a concentration of 1×10(9) CFU/mL (300 μL per tube) and the phage KP168 solution at a titer of 5×10(8) PFU/mL (60 μL per tube) were mixed at MOI of 0.005 and conventionally shaking cultured after standing for the optimal adsorption time. The phage KP168 titer was measured 0 (immediately), 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 minutes after culture, and a one-step growth curve was drawn. The experiment was repeated three times. (7) The phage KP168 solution at a titer of 2.5×10(10) PFU/mL was left to stand for 1 hour at 37, 40, 50, 60, or 70 ℃ (3 tubes at each time point, 1 mL per tube) for counting the plaques, and then the thermal stability curve was drawn. SM buffer at a pH values of 5.0, 6.0, 7.0, 7.4, 8.0, 9.0, or 10.0 were added to the phage KP168 solution at a titer of 3.0×10(10) PFU/mL, respectively. The mixed solution was left to stand for 1 hour at 37 ℃ (3 tubes of each pH, each tube containing 100 μL phage KP168 solution and 900 μL SM buffer), and then the plaques were counted, and an acid-base stability curve was drawn. (8) The phage KP168 solution was taken for DNA extraction and sequencing after dialysis as in experiment (2). The whole genome was annotated with Prokka to obtain the coding sequence of phage KP168. Nucleotide's BLAST function was used to proceed nucleic acid sequence alignment for finding a known phage with the highest similarity to the phage KP168 nucleic acid sequence, and Blastx function was used to translate the coding sequence into protein for its function prediction. The comparison with Antibiotic Resistance Genes Database and Virulence Factors Database was proceeded. (9) In a 96-well plate, at a MOI of 1.000, 0.100, 0.010 or 0.001 (3 wells per MOI), 20 μL phage KP168 solution at a initial titer of 5.8×10(10) PFU/mL was added to 200 μL host bacteria solution at a concentration of 1.5×10(8) CFU/mL (the same concentration below) for co-cultivation for 48 hours. After 200 μL host bacteria solution was left to stand for 48 hours, 20 μL phage KP168 solution at a titer of 1×10(6,) 1×10(7,) 1×10(8,) 1×10(9,) or 1×10(10) PFU/mL (3 wells per titer) was added respectively for action for 4 hours. In both experiments, 200 μL host bacteria solution added with 20 μL SM buffer (3 wells) acted as a negative control, and 220 μL LB culture medium (3 wells) acted as a blank control. Absorbance values were measured by a microplate reader, and inhibition/destruction rates of biofilm were calculated. The experiments were both repeated three times. Results: (1) The plaques of phage KP168 successfully isolated and purified were transparent and round, and its diameter was approximately 1.5 mm. (2) The phage KP168 has a regular polyhedron structure with a diameter of about 50 nm and without a tail. (3) The phage KP168 could lyse 13 of 20 strains of Klebsiella pneumoniae from burned patients, with a lysis rate of 65.0%. (4) When MOI was 1.000, the titer was the highest after co-culturing the phage KP168 with the host bacteria for 4 hours, which was the optimal MOI. (5) After the mixing of the phage KP168 with the host bacteria for 4 minutes, the percentage of the adsorbed phage reached the highest, which was the optimal adsorption time. (6) The one-step growth curve showed that during the lysis of the host bacteria by phage KP168, the incubation period was about 10 minutes, and the lysis period was about 40 minutes. (7) With the condition of 40 ℃ or pH 7.4, the number of plaques and the activity of phage KP168 reached the highest. (8) The genome of phage KP168 was a linear double-stranded DNA with a length of 40 114 bp. There were 48 possible coding sequences. It had the highest similarity to Klebsiella phage_vB_Kp1. The most similar known proteins corresponding to the translated proteins of coding sequences contained 23 hypothetical proteins and 25 proteins with known functions. No resistance genes or virulence factor genes were found. The GeneBank accession number was KT367885. (9) After 48 hours of co-cultivation of the phage KP168 and the host bacteria at each MOI, the inhibition rates of biofilm were similar, with an average of about 45%. After the phage KP168 with a titer of 1×10(9) PFU/mL acted on the biofilm formed by the host bacteria for 4 h, the destruction rate of biofilm was the highest, reaching an average of 42%. Conclusions: In this study, a bacteriophage against pan-drug resistant Klebsiella pneumoniae from a burn patient, phage KP168, is isolated from sewage, which belongs to the tailless phage. It has a wide host spectrum, short adsorption time, and short incubation period, with certain thermal and acid-base stability. Its genomic information is clear, and it does not contain resistance genes or virulence factor genes. It also has an inhibitory effect on the formation of bacterial biofilm and a destructive effect on the formed bacterial biofilm.}, } @article {pmid32023304, year = {2020}, author = {Siebert, C and Villers, C and Pavlou, G and Touquet, B and Yakandawala, N and Tardieux, I and Renesto, P}, title = {Francisella novicida and F. philomiragia biofilm features conditionning fitness in spring water and in presence of antibiotics.}, journal = {PloS one}, volume = {15}, number = {2}, pages = {e0228591}, pmid = {32023304}, issn = {1932-6203}, mesh = {Adaptation, Physiological ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Ciprofloxacin/pharmacology ; Conserved Sequence ; DNA, Bacterial/chemistry ; *Drug Resistance, Bacterial ; Francisella/drug effects/genetics/pathogenicity/*physiology ; Fresh Water/*microbiology ; Gram-Negative Bacterial Infections/microbiology ; Humans ; }, abstract = {Biofilms are currently considered as a predominant lifestyle of many bacteria in nature. While they promote survival of microbes, biofilms also potentially increase the threats to animal and public health in case of pathogenic species. They not only facilitate bacteria transmission and persistence, but also promote spreading of antibiotic resistance leading to chronic infections. In the case of Francisella tularensis, the causative agent of tularemia, biofilms have remained largely enigmatic. Here, applying live and static confocal microscopy, we report growth and ultrastructural organization of the biofilms formed in vitro by these microorganisms over the early transition from coccobacillary into coccoid shape during biofilm assembly. Using selective dispersing agents, we provided evidence for extracellular DNA (eDNA) being a major and conserved structural component of mature biofilms formed by both F. subsp. novicida and a human clinical isolate of F. philomiragia. We also observed a higher physical robustness of F. novicida biofilm as compared to F. philomiragia one, a feature likely promoted by specific polysaccharides. Further, F. novicida biofilms resisted significantly better to ciprofloxacin than their planktonic counterparts. Importantly, when grown in biofilms, both Francisella species survived longer in cold water as compared to free-living bacteria, a trait possibly associated with a gain in fitness in the natural aquatic environment. Overall, this study provides information on survival of Francisella when embedded with biofilms that should improve both the future management of biofilm-related infections and the design of effective strategies to tackle down the problematic issue of bacteria persistence in aquatic ecosystems.}, } @article {pmid32021324, year = {2020}, author = {Hu, L and Shi, Y and Xu, Q and Zhang, L and He, J and Jiang, Y and Liu, L and Leptihn, S and Yu, Y and Hua, X and Zhou, Z}, title = {Capsule Thickness, Not Biofilm Formation, Gives Rise to Mucoid Acinetobacter baumannii Phenotypes That are More Prevalent in Long-Term Infections: A Study of Clinical Isolates from a Hospital in China.}, journal = {Infection and drug resistance}, volume = {13}, number = {}, pages = {99-109}, pmid = {32021324}, issn = {1178-6973}, abstract = {BACKGROUND: Acinetobacter baumannii is a nosocomial pathogen of critical importance due to the increasing numbers of antibiotic-resistant isolates. Colonies can have a smooth or matt appearance, but also exhibit slimy, mucoid growth, with the latter being increasingly isolated in patients in recent years.

METHODS: We isolated 60 A. baumannii strains from altogether 56 patients and found that all patients were infected by mucoid strains, with four patients having also matt phenotypes in addition to the mucoid ones. The morphology of the colonies and capsules was observed. The antibiotics susceptibilities were tested, and the biofilm formation ability was determined by crystal violet staining. The whole-genome sequencing (WGS) was performed on all the strains, and then the core genome multilocus sequence typing (cgMLST) and drug resistance gene analysis were performed. Finally, a part of isolates were selected to test virulence in a Galleria mellonella model.

RESULTS: We observed much larger capsules in the mucoid strains compared to the matt isolates. But the mucoid phenotype did not correlate with the amount of biofilm produced by the strain. Almost all mucus-type A. baumannii were multi-drug resistant isolates, containing various antibiotic resistance genes. The main ST types of mucoid-type A.baumannii were ST191 and ST195, of which ST191 isolates were more virulence, while ST195 isolates were weaker.

CONCLUSION: The mucoid A. baumannii had resistance to most antibiotics and some strains had high virulence, which should be paid attention in clinical.}, } @article {pmid32021094, year = {2020}, author = {Xie, Y and Liu, X and Zhou, P}, title = {In vitro Antifungal Effects of Berberine Against Candida spp. In Planktonic and Biofilm Conditions.}, journal = {Drug design, development and therapy}, volume = {14}, number = {}, pages = {87-101}, pmid = {32021094}, issn = {1177-8881}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Berberine/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Plankton/*drug effects ; }, abstract = {PURPOSE: Antifungal resistance associated with the extensive use of antifungals and biofilm formation presents major clinical challenges. Thus, new therapeutic strategies for fungal infections are urgently required. This study aimed to evaluate the in vitro antifungal effects of the natural bioactive alkaloid berberine against Candida spp. in planktonic and biofilm conditions.

METHODS: Using the CLSI M27-A3 reference method for broth dilution antifungal susceptibility testing of yeasts, the MICs for five standard strains comprised of Candida albicans (ATCC 10231, ATCC 90028), Candida krusei (ATCC 6258), Candida glabrata (ATCC 90030), Candida dubliniensis (MYA 646), and six clinical isolates (CLC1-CLC6) were tested. The 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to evaluate the inhibitory effects of berberine against Candida biofilms. The optical density value at 490 nm was measured and illustrated using concentration-absorbance curves. Finally, the effects were quantified by confocal laser scanning microscopy (CLSM), and 3-dimensional reconstruction was performed. The viability inhibition rates, biofilm formation, and thickness decrease rates were tested and analyzed using independent-samples t-test. The differences among the five Candida strains were analyzed using one way ANOVA.

RESULTS: The MICs for the five standard strains described above were 80, 160, 10, 20, and 40 μg/mL, respectively, which was similar to that of the clinical isolates, suggesting the stable, broad-spectrum antifungal activity of berberine. Berberine exerted concentration-dependent inhibitory effects against Candida biofilms, which were enhanced with the maturation of Candida biofilms. Berberine decreased the viability of Candida biofilms, with inhibition rates by CLSM ranging from 19.89 ± 0.57% to 96.93 ± 1.37%. Following 3-dimensional reconstruction, the biofilms of the berberine-treated group displayed a poorly developed architecture, and the biofilm thickness decrease rates ranged from 15.49 ± 8.45% to 30.30 ± 15.48%.

CONCLUSION: Berberine exhibited significant antifungal activity in Candida spp. The results provide a useful reference for multiple Candida infections and biofilm infections associated with antifungal resistance. Therefore, berberine might have novel therapeutic potential as an antifungal agent or a major active component of antifungal drugs.}, } @article {pmid32020907, year = {2020}, author = {Machineni, L}, title = {Effects of biotic and abiotic factors on biofilm growth dynamics and their heterogeneous response to antibiotic challenge.}, journal = {Journal of biosciences}, volume = {45}, number = {}, pages = {}, pmid = {32020907}, issn = {0973-7138}, mesh = {Anti-Bacterial Agents/metabolism/*pharmacology ; Biofilms/*drug effects/*growth & development ; Drug Resistance, Microbial ; Micronutrients/*metabolism ; Quorum Sensing ; }, abstract = {Over the last couple of decades, with the crisis of new antimicrobial arsenal, multidrug-resistant clinical pathogens have been observed extensively. In clinical and medical settings, these persistent pathogens predominantly grow as complex heterogeneous structures enmeshed in a self-produced exopolysaccharide matrix, termed as biofilms. Since biofilms can rapidly form by adapting new environmental surroundings and have potential effect on human health, it is critical to study them promptly and consistently. Biofilm infections are challenging in the contamination of medical devices and implantations, food processing and pharmaceutical industrial settings, and in dental area caries, periodontitis and so on. The persistence of infections associated with biofilms has been mainly attributed to the increased antibiotic resistance offered by the cells growing in biofilms. In fact, it is well known that this recalcitrance of bacterial biofilms is multifactorial, and there are several resistance mechanisms that may act in parallel in order to provide an enhanced level of resistance to the biofilm. In combination, distinct resistance mechanisms significantly decrease our ability to control and eradicate biofilm-associated infections with current antimicrobial arsenal. In addition, various factors are known to influence the process of biofilm formation, growth dynamics, and their heterogeneous response towards antibiotic therapy. The current review discusses the contribution of cellular and physiochemical factors on the growth dynamics of biofilm, especially their role in antibiotic resistance mechanisms of bacterial population living in surface attached growth mode. A systematic investigation on the effects and treatment of biofilms may pave the way for novel therapeutic strategies to prevent and treat biofilms in healthcare and industrial settings.}, } @article {pmid32020424, year = {2020}, author = {Çankirili, NK and Kart, D and Çelebi-Saltik, B}, title = {Evaluation of the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa on human umbilical cord CD146+ stem cells and stem cell-based decellularized matrix.}, journal = {Cell and tissue banking}, volume = {21}, number = {2}, pages = {215-231}, doi = {10.1007/s10561-020-09815-6}, pmid = {32020424}, issn = {1573-6814}, support = {TYL-2019-17802//Hacettepe University, Scientific Research Project Coordination Unit/ ; }, mesh = {Biofilms/*growth & development ; Biomarkers/metabolism ; CD146 Antigen/*metabolism ; Cell Differentiation ; Cell Proliferation ; Cell Shape ; Cells, Cultured ; Coculture Techniques ; Extracellular Matrix/*metabolism ; Extracellular Matrix Proteins/metabolism ; Gene Expression Regulation, Bacterial ; Humans ; Proteome/metabolism ; Pseudomonas aeruginosa/genetics/*physiology/ultrastructure ; Staphylococcus aureus/genetics/*physiology/ultrastructure ; Stem Cells/*cytology ; Umbilical Cord/*cytology ; }, abstract = {This study aims to evaluate the CD146+ stem cells obtained from the human umbilical cord and their extracellular matrix proteins on in vitro Pseudomonas aeruginosa and Staphylococcus aureus biofilms to understand their possible antimicrobial activity. CD146+ stem cells were determined according to cell surface markers and differentiation capacity. Characterization of the decellularized matrix was done with DAPI, Masson's Trichrome staining and proteome analysis. Cell viability/proliferation of cells in co-cultures was evaluated by WST-1 and crystal-violet staining. The effects of cells and decellularized matrix proteins on biofilms were investigated on a drip flow biofilm reactor and their effects on gene expression were determined by RT-qPCR. We observed that CD146/105+ stem cells could differentiate adipogenically and decellularized matrix showed negative DAPI and positive collagen staining with Masson' s Trichrome. Proteome analysis of the decellularized matrix revealed some matrix components and growth factors. Although the decellularized matrix significantly reduced the cell counts of P. aeruginosa, no significant difference was observed for S. aureus cells in both groups. Supporting data was obtained from the gene expression results of P. aeruginosa with the significant down-regulation of rhlR and lasR. For S. aureus, icaADBC genes were significantly up-regulated when grown on the decellularized matrix.}, } @article {pmid32018281, year = {2020}, author = {Zavattini, A and Cowie, J and Niazi, S and Giovarruscio, M and Sauro, S and Foschi, F}, title = {Reduction of an in vitro Intraradicular Multispecies Biofilm Using Two Rotary Instrumentation Sequences.}, journal = {European journal of dentistry}, volume = {14}, number = {1}, pages = {1-7}, pmid = {32018281}, issn = {1305-7456}, abstract = {OBJECTIVE: The purpose of this research was to investigate the effect per se of two shaping and cleaning techniques on the reduction of an in vitro multispecies biofilm.

MATERIALS AND METHODS:  A total of 39 freshly extracted monoradicular teeth for periodontal reason were decoronated. Roots were sectioned longitudinally. After autoclaving, a specific stressed biofilm was grown on the root halves that were subsequently reassembled in a silicone index. Two treatments (n = 9 each)-RaCe (Schottlander; Letchworth Garden City, United Kingdom) and ProTaper Gold (PTG; Dentsply Maillefer, Baillagues, Switzerland)-were tested; three noninstrumented samples served as a control group and three were rinsed with saline. Posttreatment samples were taken at three different levels of the root. Colony-forming units were counted after incubations. Additionally, three treatments (n = 5 each)-RaCe, PTG, and saline only-were evaluated under a confocal laser scanning microscope (CLSM).

STATISTICAL ANALYSIS:  Statistical analysis was conducted using Tukey's test and analysis of variance to evaluate the post-instrumentation bioburden.

RESULTS:  Both instrumentations were able to reduce the biofilm; however, differences were not present between them (p > 0.05). CLSM showed biofilm killing and disruption through mechanical shaping alone.

CONCLUSIONS:  Intraradicular biofilm is reduced with mechanical shaping. There was no difference between RaCe and PTG systems in biofilm reduction despite differences in design, file sequence, and rotational speed.}, } @article {pmid32017602, year = {2020}, author = {Bumunang, EW and Ateba, CN and Stanford, K and McAllister, TA and Niu, YD}, title = {Biofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons.}, journal = {Canadian journal of microbiology}, volume = {66}, number = {4}, pages = {328-336}, doi = {10.1139/cjm-2019-0554}, pmid = {32017602}, issn = {1480-3275}, mesh = {*Biofilms ; Equipment Contamination ; Escherichia coli Proteins/genetics/metabolism ; Food Handling/*instrumentation ; Shiga-Toxigenic Escherichia coli/genetics/growth & development/*physiology ; Stainless Steel/chemistry ; }, abstract = {This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air-liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air-liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.}, } @article {pmid32013708, year = {2021}, author = {Kamble, E and Pardesi, K}, title = {Antibiotic Tolerance in Biofilm and Stationary-Phase Planktonic Cells of Staphylococcus aureus.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {27}, number = {1}, pages = {3-12}, doi = {10.1089/mdr.2019.0425}, pmid = {32013708}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Plankton/*drug effects ; Staphylococcus aureus/*drug effects/genetics ; Time Factors ; }, abstract = {The ability of Staphylococcus aureus to form biofilms and persisters is a major cause of recalcitrant infections that are difficult to treat. We have examined time-dependent variation in persister population present in stationary-phase planktonic cells and biofilms of S. aureus when treated with bactericidal antibiotics having different cellular targets. Fourteen isolates identified as S. aureus were found to be resistant to three to nine classes of antibiotics tested according to the CLSI guidelines. Among the sensitive isolates, S48 was found to be the strongest biofilm producer, whereas J6 was the weakest. The four antibiotics, ciprofloxacin, daptomycin, tobramycin, and vancomycin, inhibited biofilm formation, whereas daptomycin was the strongest in disrupting 24-hr-old biofilm. Treatment of stationary-phase planktonic cells with 100 × minimum inhibitory concentration (MIC) of these antibiotics showed a typical biphasic pattern indicating the presence of persister cells. Twenty-four-hour-old biofilm of the two isolates tested at 100 × MIC of the antibiotics showed a similar biphasic pattern. Tolerance of biofilm cells was greater as compared with planktonic cells, which could be due to elevated number of persisters found in the biofilm as compared with planktonic cells.}, } @article {pmid32013373, year = {2020}, author = {Kirmusaoglu, S}, title = {Improved β-Lactam Susceptibility Against ica-Dependent Biofilm-Embedded Staphylococcus aureus by 2-Aminothiazole.}, journal = {Clinical laboratory}, volume = {66}, number = {1}, pages = {}, doi = {10.7754/Clin.Lab.2020.191112}, pmid = {32013373}, issn = {1433-6510}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial/drug effects ; Humans ; *Methicillin-Resistant Staphylococcus aureus/drug effects/genetics ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; Thiazoles/*pharmacology ; beta-Lactams/*pharmacology ; }, abstract = {BACKGROUND: Due to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) producing biofilm, causing recurrent infections worldwide, new therapeutic combinations need to be discovered to prevent resistance and to make treatment available. It was aimed to improve β-lactam susceptibility against ica-dependent biofilm-embedded Staphylococcus aureus (S. aureus), even in blaZ and mecA carriers, by 2-aminothiazole.

METHODS: Virulence genes in isolates were detected by qRT-PCR. MICs, MBCs of 2-aminothiazole and β-lactams against planktonic and sessile ica-dependent biofilm-producer isolates were investigated. Activities of 2-aminothiazole combined β-lactams against sessile one MRSA ATCC 43300, one MRSA, and two MSSA were investigated by checkerboard-assay.

RESULTS: Activities of 2-aminothiazole combined β-lactams were found synergistic and partially-synergistic against both biofilm-embedded MRSA and MSSA-isolates with FIC-indexes ranging between 0.193 - 0.387 and 0.535 - 0.745 and between 0.358 - 0.415 and 0.707 - 1.0, respectively. MICs of β-lactams against MSSA and MRSA were decreased 2- to 8-fold and 0- to 8-fold by sub-MICs of 2-aminothiazole, respectively.

CONCLUSIONS: Sub-MIC 2-aminothiazole combined Sub-MIC β-lactams can be a choice in varying applications to treat biofilm-associated staphylococcal infections.}, } @article {pmid32013221, year = {2020}, author = {Yuan, G and Li, P and Xu, X and Li, P and Zhong, Q and He, S and Yi, H and Yi, W and Guan, Y and Wen, ZT}, title = {Azalomycin F5a Eradicates Staphylococcus aureus Biofilm by Rapidly Penetrating and Subsequently Inducing Cell Lysis.}, journal = {International journal of molecular sciences}, volume = {21}, number = {3}, pages = {}, pmid = {32013221}, issn = {1422-0067}, support = {81660578, 81960636 and 81460529//National Natural Science Foundation of China/ ; 20192ACBL20020//Natural Science Foundation of Jiangxi Province/ ; }, mesh = {Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Biofilms/*drug effects ; DNA/chemistry/metabolism ; Deoxyribonuclease I/metabolism ; Macrolides/chemistry/metabolism/*pharmacology ; Microbial Sensitivity Tests ; Staphylococcus aureus/*physiology ; }, abstract = {Antimicrobial resistance has emerged as a serious threat to public health. Bacterial biofilm, as a natural lifestyle, is a major contributor to resistance to antimicrobials. Azalomycin F5a, a natural guanidine-containing polyhydroxy macrolide, has remarkable activities against Gram-positive bacteria, including Staphylococcus aureus, a major causative agent of hospital-acquired infections. To further evaluate its potential to be developed as a new antimicrobial agent, its influence on S. aureus biofilm formation was evaluated using the crystal violet method, and then its eradication effect against mature biofilms was determined by confocal laser scanning microscopy, the drop plate method, and regrowth experiments. The results showed that azalomycin F5a could significantly inhibit S. aureus biofilm formation, and such effects were concentration dependent. In addition, it can also eradicate S. aureus mature biofilms with the minimum biofilm eradication concentration of 32.0 μg/mL. As extracellular deoxyribonucleic acid (eDNA) plays important roles in the structural integrity of bacterial biofilm, its influence on the eDNA release in S. aureus biofilm was further analyzed using gel electrophoresis. Combined with our previous works, these results indicate that azalomycin F5a could rapidly penetrate biofilm and causes damages to the cell membrane, leading to an increase in DNase release and eventually eradicating S. aureus biofilm.}, } @article {pmid32011777, year = {2020}, author = {Davis, SC and Pastar, I}, title = {Reply to "Questioning the use of an acute porcine wound model to assess anti-biofilm activity of dressings".}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {28}, number = {3}, pages = {429-430}, doi = {10.1111/wrr.12795}, pmid = {32011777}, issn = {1524-475X}, mesh = {Animals ; Bandages ; Biofilms ; *Pseudomonas aeruginosa ; Silver ; Swine ; Wound Healing ; *Wound Infection ; }, } @article {pmid32011702, year = {2020}, author = {Ceballos Garzon, A and Amado, D and Robert, E and Parra Giraldo, CM and Le Pape, P}, title = {Impact of calmodulin inhibition by fluphenazine on susceptibility, biofilm formation and pathogenicity of caspofungin-resistant Candida glabrata.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {75}, number = {5}, pages = {1187-1193}, doi = {10.1093/jac/dkz565}, pmid = {32011702}, issn = {1460-2091}, mesh = {Antifungal Agents/pharmacology/therapeutic use ; Biofilms ; Calmodulin/genetics ; *Candida glabrata/genetics ; Caspofungin ; Drug Resistance, Fungal ; Echinocandins/pharmacology ; *Fluphenazine/pharmacology ; Microbial Sensitivity Tests ; Virulence ; }, abstract = {BACKGROUND: In recent decades, Candida glabrata has emerged as a frequent cause of life-threatening fungal infection. In C. glabrata, echinocandin resistance is associated with mutations in FKS1/FKS2 (β-1,3-glucan synthase). The calmodulin/calcineurin pathway is implicated in response to antifungal stress and calcineurin gene disruption specifically reverses Fks2-mediated resistance of clinical isolates.

OBJECTIVES: We evaluated the impact of calmodulin inhibition by fluphenazine in two caspofungin-resistant C. glabrata isolates.

METHODS: C. glabrata isolates were identified by ITS1/ITS4 (where ITS stands for internal transcribed spacer) sequencing and the echinocandin target FKS1/FKS2 genes were sequenced. Susceptibility testing of caspofungin in the presence of fluphenazine was performed by a modified CLSI microbroth dilution method. The effect of the fluphenazine/caspofungin combination on heat stress (37°C or 40°C), oxidative stress (0.2 and 0.4 mM menadione) and biofilm formation (polyurethane catheter) was analysed. A Galleria mellonella model using blastospores (1 × 109 cfu/mL) was developed to evaluate the impact of this combination on larval survival.

RESULTS: F659del was found in the FKS2 gene of both resistant strains. In these clinical isolates, fluphenazine increased susceptibility to caspofungin and reduced their thermotolerance. Furthermore, the fluphenazine/caspofungin combination significantly impaired biofilm formation in an in vitro polyurethane catheter model. All these features participated in the increasing survival of infected G. mellonella after combination treatment in comparison with caspofungin alone.

CONCLUSIONS: In a repurposing strategy, our findings confirm that calmodulin could provide a relevant target in life-threatening fungal infectious diseases.}, } @article {pmid32010109, year = {2019}, author = {Hwang, SH and Park, JH and Lee, B and Choi, SH}, title = {A Regulatory Network Controls cabABC Expression Leading to Biofilm and Rugose Colony Development in Vibrio vulnificus.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {3063}, pmid = {32010109}, issn = {1664-302X}, abstract = {Biofilms provide bacteria with protection from environmental stresses and host immune defenses. The pathogenic marine bacterium Vibrio vulnificus forms biofilms and colonizes environmental niches such as oysters. The cabABC operon encodes an extracellular matrix protein CabA and the corresponding type I secretion system, which are essential for biofilm and rugose colony development of V. vulnificus. In this study, molecular biological analyses revealed the roles of three transcriptional regulators BrpR, BrpT, and BrpS in the regulatory pathway for the cabABC operon. BrpR induces brpT and BrpT in turn activates the cabABC operon in a sequential cascade, contributing to development of robust biofilm structures. BrpT also activates brpS, but BrpS represses brpT, constituting a negative feedback loop that stabilizes brpT expression. BrpT and BrpS directly bind to specific sequences upstream of cabA, and they constitute a feedforward loop in which BrpT induces brpS and together with BrpS activates cabABC, leading to precise regulation of cabABC expression. Accordingly, BrpS as well as BrpT plays a crucial role in complete development of rugose colonies. This elaborate network of three transcriptional regulators BrpR, BrpT, and BrpS thus tightly controls cabABC regulation, and contributes to successful development of robust biofilms and rugose colonies in V. vulnificus.}, } @article {pmid32010107, year = {2019}, author = {Völkel, S and Hein, S and Benker, N and Pfeifer, F and Lenz, C and Losensky, G}, title = {How to Cope With Heavy Metal Ions: Cellular and Proteome-Level Stress Response to Divalent Copper and Nickel in Halobacterium salinarum R1 Planktonic and Biofilm Cells.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {3056}, pmid = {32010107}, issn = {1664-302X}, abstract = {Halobacterium salinarum R1 is an extremely halophilic archaeon capable of adhesion and forming biofilms, allowing it to adjust to a range of growth conditions. We have recently shown that living in biofilms facilitates its survival under Cu[2+] and Ni[2+] stress, with specific rearrangements of the biofilm architecture observed following exposition. In this study, quantitative analyses were performed by SWATH mass spectrometry to determine the respective proteomes of planktonic and biofilm cells after exposition to Cu[2+] and Ni[2+].Quantitative data for 1180 proteins were obtained, corresponding to 46% of the predicted proteome. In planktonic cells, 234 of 1180 proteins showed significant abundance changes after metal ion treatment, of which 47% occurred in Cu[2+] and Ni[2+] treated samples. In biofilms, significant changes were detected for 52 proteins. Only three proteins changed under both conditions, suggesting metal-specific stress responses in biofilms. Deletion strains were generated to assess the potential role of selected target genes. Strongest effects were observed for ΔOE5245F and ΔOE2816F strains which exhibited increased and decreased biofilm mass after Ni[2+] exposure, respectively. Moreover, EPS obviously plays a crucial role in H. salinarum metal ion resistance. Further efforts are required to elucidate the molecular basis and interplay of additional resistance mechanisms.}, } @article {pmid32009731, year = {2019}, author = {Merigo, E and Chevalier, M and Conti, S and Ciociola, T and Fornaini, C and Manfredi, M and Vescovi, P and Doglio, A}, title = {Antimicrobial effect on Candida albicans biofilm by application of different wavelengths and dyes and the synthetic killer decapeptide KP.}, journal = {Laser therapy}, volume = {28}, number = {3}, pages = {180-186}, pmid = {32009731}, issn = {0898-5901}, abstract = {The aim of this study was to test the application in vitro of different laser wavelengths at a low fluence in combination or not with proper photosensitizing dyes on Candida albicans biofilm with or without a synthetic killer decapeptide (KP). Candida albicans SC5314 was grown on Sabouraud dextrose agar plates at 37°C for 24 h. Cells were suspended in RPMI 1640 buffered with MOPS and cultured directly on the flat bottom of 96-wells plates. The previously described killer decapeptide KP was used in this study. Three different combinations of wavelengths and dyes were applied, laser irradiation has been performed at a fluence of 10 J/cm[2]. The effect on C. albicans biofilm was evaluated by the XTT assay. Microscopic observations were realized by fluorescence optic microscopy with calcofluor white and propidium iodide. Compared with control, no inhibition of C. albicans biofilm viability was obtained with application of red, blue and green lasers alone or with any combination of red diode laser, toluidine blue and KP. The combined application of blue diode laser with curcumin and/or KP showed always a very significant inhibition, as curcumin alone and the combination of curcumin and KP did, while combination of blue diode laser and KP gave a less significant inhibition, the same obtained with KP alone. The combined application of green diode laser with erythrosine and/or KP showed always a very significant inhibition, as the combination of erythrosine and KP did, but no difference was observed with respect to the treatment with erythrosine alone. Again, combination of green diode laser and KP gave a significant inhibition, although paradoxically lower than the one obtained with KP alone. Treatment with KP alone, while reducing biofilm viability did not cause C. albicans death in the adopted experimental conditions. On the contrary, combined treatment with blue laser, curcumin and KP, as well as green laser, erythrosine and KP led to death most C. albicans cells. The combination of laser light at a fluence of 10 J/cm[2] and the appropriate photosensitizing agent, together with the use of KP, proved to exert differential effects on C. albicans biofilm.}, } @article {pmid32009660, year = {2020}, author = {Palmer, MB and Wang, Y and White, AP}, title = {Discovering CsgD Regulatory Targets in Salmonella Biofilm Using Chromatin Immunoprecipitation and High-Throughput Sequencing (ChIP-seq).}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {155}, pages = {}, doi = {10.3791/60736}, pmid = {32009660}, issn = {1940-087X}, mesh = {*Biofilms ; Chromatin Immunoprecipitation/*methods ; High-Throughput Nucleotide Sequencing/*methods ; Salmonella typhimurium/*genetics ; Transcription Factors/*metabolism ; }, abstract = {Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is a technique that can be used to discover the regulatory targets of transcription factors, histone modifications, and other DNA-associated proteins. ChIP-seq data can also be used to find differential binding of transcription factors in different environmental conditions or cell types. Initially, ChIP was performed through hybridization on a microarray (ChIP-chip); however, ChIP-seq has become the preferred method through technological advancements, decreasing financial barriers to sequencing, and massive amounts of high-quality data output. Techniques of performing ChIP-seq with bacterial biofilms, a major source of persistent and chronic infections, are described in this protocol. ChIP-seq is performed on Salmonella enterica serovar Typhimurium biofilm and planktonic cells, targeting the master biofilm regulator, CsgD, to determine differential binding in the two cell types. Here, we demonstrate the appropriate amount of biofilm to harvest, normalizing to a planktonic control sample, homogenizing biofilm for cross-linker access, and performing routine ChIP-seq steps to obtain high quality sequencing results.}, } @article {pmid32009221, year = {2020}, author = {Schubiger, CB and Hoang, KHT and Häse, CC}, title = {Sodium antiporters of Pseudomonas aeruginosa in challenging conditions: effects on growth, biofilm formation, and swarming motility.}, journal = {Journal, genetic engineering & biotechnology}, volume = {18}, number = {1}, pages = {4}, pmid = {32009221}, issn = {2090-5920}, abstract = {BACKGROUND: Pseudomonas aeruginosa is a bacterial pathogen that can cause grave and sometimes chronic infections in patients with weakened immune systems and cystic fibrosis. It is expected that sodium/proton transporters in the cellular membrane are crucial for the organism's survival and growth under certain conditions, since many cellular processes rely on the maintenance of Na[+] and H[+] transmembrane gradients.

RESULTS: This study focused on the role of the primary and secondary proton and/or sodium pumps Mrp, Nuo, NhaB, NhaP, and NQR for growth, biofilm formation, and swarming motility in P. aeruginosa. Using mutants with gene deletions, we investigated the impact of each sodium pump's absence on the overall growth, biofilm formation, motility, and weak acid tolerance of the organism. We found that the absence of some, but not all, of the sodium pumps have a deleterious effect on the different phenotypes of P. aeruginosa.

CONCLUSION: The absence of the Mrp sodium/proton antiporter was clearly important in the organism's ability to survive and function in environments of higher pH and sodium concentrations, while the absence of Complex I, which is encoded by the nuo genes, had some consistent impact on the organism's growth regardless of the pH and sodium concentration of the environment.}, } @article {pmid32008118, year = {2020}, author = {Jin, X and Marshall, JS and Wargo, MJ}, title = {Hybrid Model of Bacterial Biofilm Growth.}, journal = {Bulletin of mathematical biology}, volume = {82}, number = {2}, pages = {27}, doi = {10.1007/s11538-020-00701-6}, pmid = {32008118}, issn = {1522-9602}, mesh = {Bacteria/growth & development/metabolism ; Biofilms/*growth & development ; Biomechanical Phenomena ; Computational Biology ; Computer Simulation ; Elastic Modulus ; Extracellular Polymeric Substance Matrix/metabolism ; Humans ; Imaging, Three-Dimensional ; Mathematical Concepts ; *Models, Biological ; Systems Biology ; Viscosity ; Water/metabolism ; }, abstract = {Bacterial biofilms play a critical role in environmental processes, water treatment, human health, and food processing. They exhibit highly complex dynamics due to the interactions between the bacteria and the extracellular polymeric substance (EPS), water, and nutrients and minerals that make up the biofilm. We present a hybrid computational model in which the dynamics of discrete bacterial cells are simulated within a multiphase continuum, consisting of EPS and water as separate interacting phases, through which nutrients and minerals diffuse. Bacterial cells in our model consume water and nutrients in order to grow, divide, and produce EPS. Consequently, EPS flows outward from the bacterial colony, while water flows inward. The model predicts bacterial colony formation as a treelike structure. The distribution of bacterial growth and EPS production is found to be sensitive to the pore spacing between bacteria and the consumption of nutrients within the bacterial colony. Forces that are sometimes neglected in biofilm simulations, such as lubrication force between nearby bacterial cells and osmotic (swelling) pressure force resulting from gradients in EPS concentration, are observed to have an important effect on biofilm growth via their influence on bacteria pore spacing and associated water/nutrient percolation into the bacterial colony.}, } @article {pmid32007876, year = {2020}, author = {Ribera-Pi, J and Badia-Fabregat, M and Arias, D and Gómez, V and Taberna, E and Sanz, J and Martínez-Lladó, X and Jubany, I}, title = {Coagulation-flocculation and moving bed biofilm reactor as pre-treatment for water recycling in the petrochemical industry.}, journal = {The Science of the total environment}, volume = {715}, number = {}, pages = {136800}, doi = {10.1016/j.scitotenv.2020.136800}, pmid = {32007876}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors ; Flocculation ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Water recycling and reuse is of important value in water-using sectors like petrochemical industry. The aim of this research was to optimise the pre-treatment of petrochemical wastewater to undergo a further membrane treatment, with the final objective of water recycling within the same industry. Laboratory coagulation-flocculation tests prior to biological treatment were performed using Actiflo® Veolia commercial technology and an optimal coagulant dose of 30 mg/L ferric chloride was obtained. A bench-scale Moving Bed Biofilm Reactor (MBBR) system with two sequential reactors with working volumes of 5 L was filled with Z-carriers at 35% of their working volume. Organic loading rate (OLR) was varied from 0.2 to 3.25 kg/(m[3] d) and the hydraulic retention time (HRT) ranged from 23.4 h to 4.5 h. High soluble chemical oxygen demand (sCOD) removals were obtained in stationary states (80-90%) and the calculated maximum sCOD that the system could degrade was 4.96 ± 0.01 kg/(m[3] d) at 23 ± 2 °C. Changes in feed composition did not decrease sCOD removals showing that MBBR is a robust technology and the coagulation-flocculation step could be by-passed. Further removal of total suspended solids (TSS) and turbidity from the MBBR effluent would be required before a reverse osmosis (RO) step could be performed. A biofilm-forming genus, Haliscomenobacter spp., and an oil degrading genus Flavobacterium spp. were found in all the attached biomass samples. Acinetobacter spp. was the major bacterial genera found in suspended biomass. Proteobacteria and Bacteroidetes were the major phyla detected in the carrier samples while Proteobacteria the main one detected in the suspended biomass. The lack of fungal annotated sequences in databases led to a major proportion of fungal sequences being categorized as unclassified Fungi. The results obtained indicate that MBBR is an appropriate technology for hydrocarbon-degrading microorganism growth and, thus, for petrochemical wastewater pre-treatment for water regeneration.}, } @article {pmid32006178, year = {2020}, author = {Cholley, AC and Traoré, O and Hennequin, C and Aumeran, C}, title = {Klebsiella pneumoniae survival and regrowth in endoscope channel biofilm exposed to glutaraldehyde and desiccation.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {39}, number = {6}, pages = {1129-1136}, doi = {10.1007/s10096-020-03818-7}, pmid = {32006178}, issn = {1435-4373}, mesh = {Biofilms/drug effects/*growth & development ; Colony Count, Microbial ; *Desiccation ; Disinfection ; Endoscopes/*microbiology ; Glutaral/*pharmacology ; Humans ; Klebsiella pneumoniae/drug effects/growth & development/*physiology ; Microbial Viability ; Stress, Physiological ; }, abstract = {Biofilm in endoscopes is a major problem that can result in failure of disinfection. We studied the survival of K. pneumoniae in a biofilm formed on endoscope tubes subjected to combined chemical and physical stresses. We monitored bacterial survival in the biofilm after the action of 1% and 2% GTA either immediately or after 15 days of desiccation and described the ability of surviving bacteria to recolonize endoscope tubing in a dynamic model. There were surviving bacteria after 5-min exposure to 2% and 1% GTA. The percentage of survivors after 2% and 1% GTA was greater when the GTA treatment was performed after 15 days of prior desiccation of the biofilm. The survivors were able to recolonize and reform biofilm on abiotic surfaces probably because of the survival of persisters in a viable but non-culturable state in the biofilm. Our findings emphasize that the current guidelines on endoscope reprocessing should be strictly followed but that once constituted the biofilm in endoscope tubing will be very difficult to eradicate with present practices.}, } @article {pmid32005827, year = {2020}, author = {Kim, HM and Davey, ME}, title = {Synthesis of ppGpp impacts type IX secretion and biofilm matrix formation in Porphyromonas gingivalis.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {1}, pages = {5}, pmid = {32005827}, issn = {2055-5008}, support = {R01 DE019117/DE/NIDCR NIH HHS/United States ; R01 DE024580/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*metabolism ; Bacteroidaceae Infections/microbiology/*mortality ; Biofilms/*growth & development ; Disease Models, Animal ; Gene Expression Regulation, Bacterial ; Guanosine Pentaphosphate/*biosynthesis ; Lepidoptera/microbiology ; Porphyromonas gingivalis/metabolism/*physiology ; Signal Transduction ; Stress, Physiological ; Survival Analysis ; Virulence ; }, abstract = {In order to persist, bacteria need to adjust their physiological state in response to external and internal cues. External stimuli are often referred to as stressors. The stringent response, mediated by the alarmone (p)ppGpp, is central to the stress response in many bacteria; yet, there is limited knowledge regarding the role of (p)ppGpp signaling in bacteria belonging to the phylum Bacteroidetes. Like its counterparts in the gut (e.g., Bacteroides thetaiotaomicron and Bacteroides fragilis), Porphyromonas gingivalis persists in close association with its human host. Given the potential for numerous perturbations in the oral cavity, and the fact that P. gingivalis can enter and replicate within host cells, we hypothesized that (p)ppGpp is a key signaling molecule for stress adaptation and persistence. Here, we show that accumulation of ppGpp in P. gingivalis is governed by two homologous enzymes, designated Rel, and RshB, and that ppGpp signaling affects growth rate, survival, biofilm formation, production of outer membrane vesicles, and expression of genes encoding type IX secretion structural and cargo proteins. Overall, our findings provide a potential mechanism by which biofilm formation and virulence of P. gingivalis are integrated via ppGpp signaling, a regulatory mechanism central to bacterial survival in dynamic environments.}, } @article {pmid32004708, year = {2020}, author = {Ouyang, K and Mortimer, M and Holden, PA and Cai, P and Wu, Y and Gao, C and Huang, Q}, title = {Towards a better understanding of Pseudomonas putida biofilm formation in the presence of ZnO nanoparticles (NPs): Role of NP concentration.}, journal = {Environment international}, volume = {137}, number = {}, pages = {105485}, doi = {10.1016/j.envint.2020.105485}, pmid = {32004708}, issn = {1873-6750}, mesh = {*Biofilms ; *Nanoparticles ; *Pseudomonas putida/growth & development ; Quorum Sensing ; *Zinc Oxide ; }, abstract = {Elucidating the effects of nanoparticles (NPs) on key bacterial functions not only deepens our understanding of nano-toxicity mechanisms, but also guides us in the design criteria for manufacturing safe nanomaterials. In this study, bacterial growth, biofilm development and the expression of biofilm-related genes were monitored in Pseudomonas putida KT2440, a plant-beneficial bacterium, following exposure to ZnO NPs. Low concentrations of NPs (0.5-30 mg L[-1]) significantly promoted bacterial growth and biofilm formation, while higher concentrations (>30 mg L[-1]) significantly inhibited biofilm formation. Confocal laser scanning microscopy revealed that microscope slides coated with 0.5 mg L[-1] of ZnO NPs showed enhanced bacterial colonization and biomass production, but at higher concentrations (250 mg L[-1]), biomass production was about 11 times lower than that of the substrate without NPs. Increased protein and sugar contents of the biofilm matrix corroborated the stimulating effects of low concentrations of ZnO NPs. Physiological data were supported by changes in the expression of genes associated with oxidative stress and biofilm development. ZnO NPs at 0.5 mg L[-1] stimulated the expression of quorum sensing, lipopolysaccharide biosynthesis, and antibiotic resistance genes; high concentrations of ZnO NPs (250 mg L[-1]) down-regulated biofilm formation-related genes and up-regulated antioxidant genes. Our results indicate that long-term release of low concentrations of ZnO NPs to the environment would promote undesired biofilm formation and increased resistance to antibiotics.}, } @article {pmid32003349, year = {2019}, author = {Ralte, Z and Naina, P and Amladi, A and John, M and Anndan, S and Varghese, AM}, title = {Determination of Biofilm-Forming Capacity of Otopathogens Isolated from Discharging Ears in Children with Chronic Otitis Media.}, journal = {Indian journal of medical microbiology}, volume = {37}, number = {3}, pages = {442-445}, doi = {10.4103/ijmm.IJMM_19_404}, pmid = {32003349}, issn = {1998-3646}, mesh = {Biofilms ; Child ; Female ; Humans ; Methicillin-Resistant Staphylococcus aureus/*pathogenicity ; Microbial Sensitivity Tests ; Nasopharynx/microbiology ; Otitis Media/*microbiology ; Staphylococcus aureus/*pathogenicity ; }, abstract = {Chronic otitis media is a common disease of the developing world with persistent ear discharge, leading to major complications. This study describes the microorganisms isolated from the middle ear and nasopharynx of children with chronically discharging ears. Middle ear and nasopharyngeal swabs from 89 children were studied, and the microorganisms isolated were assessed for biofilm-forming ability. Methicillin-susceptible Staphylococcus aureus was common in the nasopharynx, while the middle ear showed predominantly pseudomonas and Methicillin-resistant S. aureus. Pseudomonas aeruginosa showed strong biofilm formation, whereas Escherichia coli, Proteus sp. and Providentia sp. were weak biofilm producers. S. aureus isolates were negative for biofilm formation.}, } @article {pmid32002601, year = {2020}, author = {Morinaga, K and Yoshida, K and Takahashi, K and Nomura, N and Toyofuku, M}, title = {Peculiarities of biofilm formation by Paracoccus denitrificans.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {6}, pages = {2427-2433}, pmid = {32002601}, issn = {1432-0614}, support = {19H02866//Ministry of Education, Culture, Sports, Science and Technology/ ; 19H05682//Ministry of Education, Culture, Sports, Science and Technology/ ; 19H05682//Ministry of Education, Culture, Sports, Science and Technology/ ; 16H06382//Ministry of Education, Culture, Sports, Science and Technology/ ; JPMJER1502//Exploratory Research for Advanced Technology/ ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Membrane Proteins/metabolism ; Paracoccus denitrificans/*physiology ; *Quorum Sensing ; }, abstract = {Most bacteria form biofilms, which are thick multicellular communities covered in extracellular matrix. Biofilms can become thick enough to be even observed by the naked eye, and biofilm formation is a tightly regulated process. Paracoccus denitrificans is a non-motile, Gram-negative bacterium that forms a very thin, unique biofilm. A key factor in the biofilm formed by this bacterium is a large surface protein named biofilm-associated protein A (BapA), which was recently reported to be regulated by cyclic diguanosine monophosphate (cyclic-di-GMP or c-di-GMP). Cyclic-di-GMP is a major second messenger involved in biofilm formation in many bacteria. Though cyclic-di-GMP is generally reported as a positive regulatory factor in biofilm formation, it represses biofilm formation in P. denitrificans. Furthermore, quorum sensing (QS) represses biofilm formation in this bacterium, which is also reported as a positive regulator of biofilm formation in most bacteria. The QS signal used in P. denitrificans is hydrophobic and is delivered through membrane vesicles. Studies on QS show that P. denitrificans can potentially form a thick biofilm but maintains a thin biofilm under normal growth conditions. In this review, we discuss the peculiarities of biofilm formation by P. denitrificans with the aim of deepening the overall understanding of bacterial biofilm formation and functions.}, } @article {pmid32000130, year = {2020}, author = {Sonwani, RK and Swain, G and Giri, BS and Singh, RS and Rai, BN}, title = {Biodegradation of Congo red dye in a moving bed biofilm reactor: Performance evaluation and kinetic modeling.}, journal = {Bioresource technology}, volume = {302}, number = {}, pages = {122811}, doi = {10.1016/j.biortech.2020.122811}, pmid = {32000130}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; *Biofilms ; Bioreactors ; *Congo Red ; Kinetics ; Waste Disposal, Fluid ; }, abstract = {The biodegradation of Congo red dye was performed using polyurethane foam-polypropylene immobilized Bacillus sp. MH587030.1 in a moving bed biofilm reactor (MBBR). The central composite design (CCD) based response surface methodology (RSM) was used to optimize the process parameters; pH, Congo red concentration, and media filling ratio, and optimum conditions were observed to be 7.0, 50 mg/L, and 45%, respectively in batch MBBR. At optimum condition, MBBR was operated in continuous mode at different flow rates (25-100 mL/h) over a period of 564 h. The maximum removal efficiency (RE) and elimination capacity (EC) were obtained as 95.7% and 57.6 mg/L·day, respectively under steady-state. The kinetics of Congo red biodegradation at various flow rates were evaluated by a modified Stover-Kincannon model, and kinetic constants; KB and Umax were found to be 0.253 g/L·day and 0.263 g/L·day, respectively.}, } @article {pmid32000116, year = {2020}, author = {Chen, J and Wang, Y}, title = {Genetic determinants of Salmonella enterica critical for attachment and biofilm formation.}, journal = {International journal of food microbiology}, volume = {320}, number = {}, pages = {108524}, doi = {10.1016/j.ijfoodmicro.2020.108524}, pmid = {32000116}, issn = {1879-3460}, mesh = {Bacterial Adhesion/*genetics ; Biofilms/*growth & development ; Escherichia coli/genetics ; Genes, Bacterial/genetics ; Humans ; Mutagenesis, Insertional ; Mutation ; Salmonella enterica/*genetics/physiology ; }, abstract = {Salmonella is a bacterial pathogen frequently involved in human gastrointestinal infections including those associated with low-moisture foods such as dehydrated food powders/spices, vegetable seeds, and tree nuts. The survival/persistence of Salmonella on low moisture foods and in dry environments is enhanced by its ability in developing biofilms. This study was undertaken to identify the genetic determinants critical for Salmonella attachment and biofilm formation. E. coli SM10 lambda pir, with a kanamycin resistant marker on mini-Tn10 (mini-Tn10:lacZ:kan[r]), an ampicillin resistant marker on the mini-Tn10-bearing suicidal plasmid pLBT and a streptomycin sensitive marker on the SM10 chromosome, was used as a donor (amp[r], kan[r], strep[s]), and three Salmonella strains (amp[s], kan[s], strep[r]) were used as recipients in a transposon mutagenesis study. The donor and each recipient were co-incubated overnight on tryptic soy agar at 37 °C, and mutant colonies (amp[s], kan[r], strep[r]) were subsequently selected. A single-banded degenerate PCR product, amplified from each mutant genome using oligonucleotide primers derived from the end of min-Tn10 and restriction enzyme EcoR I- or Pst I-recognizing sequence, were analyzed using the Sanger sequencing technology. Acquired DNA sequences were compared to those deposited in the Genbank using BLAST search. Cells of Salmonella mutants accumulated either significantly more or less (P < 0.05) biofilms than their parent cells on polystyrene surface. Sequence analysis of degenerate PCR products revealed that the mini-Tn10 from pLBT had inserted into the cdg, trx, fadI or rxt on Salmonella chromosomes. Results of the research will likely help strategize future antimicrobial intervention for control of pathogen attachment and biofilm formation.}, } @article {pmid31999592, year = {2020}, author = {Li, G and Wu, Y and Li, Y and Hong, Y and Zhao, X and Reyes, PI and Lu, Y}, title = {Early stage detection of Staphylococcus epidermidis biofilm formation using MgZnO dual-gate TFT biosensor.}, journal = {Biosensors & bioelectronics}, volume = {151}, number = {}, pages = {111993}, doi = {10.1016/j.bios.2019.111993}, pmid = {31999592}, issn = {1873-4235}, mesh = {Bacterial Adhesion/drug effects ; *Biofilms ; *Biosensing Techniques ; Humans ; Nanostructures/*chemistry ; Staphylococcus epidermidis/genetics/*isolation & purification ; Zinc Oxide/chemistry ; }, abstract = {Early stage detection of biofilm formation is an important aspect of microbial research because once formed, biofilms show serious tolerance to antibiotics in contrast to the free-floating bacteria, which significantly increases the difficulty for clinical treatment of bacterial infections. The early stage detection technology is desired to improve the efficiency of medical treatments. In this work, we present a biosensor consisting of a magnesium zinc oxide (MZO) dual gate thin-film transistor (DGTFT) as the actuator and an MZO nanostructure (MZOnano) array coated conducting pad as the extended sensing gate for the early stage detection of Staphylococcus epidermidis (S. epidermidis) biofilm formation. S. epidermidis bacteria were cultured in vitro on the nanostructure modified sensing pad. Charge transfer occurs between microbial cells and the MZOnano during the initial bacterial adhesion stage. Such electrical signals, which represent the onset of biofilm formation, were dynamically detected by the DGTFT where the top gate electrode was connected to the extended MZOnano sensing pad and the bottom gate was used for biasing the device into the optimum characteristic region for high sensitivity and stable operation. The testing results show that a current change of ~80% is achieved after ~200 min of bacterial culturing. A crystal violet staining-based assay shows that tiny bacterial microcolonies just start to form at 200 min, and that it would take approximately 24 h to form matured biofilms. This technology enables medical professionals to act promptly on bacterial infection before biofilms get fully established.}, } @article {pmid31999500, year = {2020}, author = {Ferreira-Filho, JCC and Marre, ATO and de Sá Almeida, JS and Lobo, LA and Farah, A and Romanos, MTV and Maia, LC and Valença, AMG and Fonseca-Gonçalves, A}, title = {Therapeutic Potential of Bauhinia forficata Link in Dental Biofilm Treatment.}, journal = {Journal of medicinal food}, volume = {23}, number = {9}, pages = {998-1005}, doi = {10.1089/jmf.2019.0277}, pmid = {31999500}, issn = {1557-7600}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Bauhinia/*chemistry ; Biofilms/*drug effects ; Cattle ; Cells, Cultured ; Dental Caries/*prevention & control ; Fibroblasts/drug effects ; Hardness ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; }, abstract = {The oral cytotoxicity, antimicrobial and anti-demineralizing effects of a tincture from Bauhinia forficata Link tincture (BFLT) were evaluated in vitro and ex vivo. Susceptibility tests (minimum inhibitory and microbicidal concentrations-MIC and time-kill assay-MMC) were performed against planktonic oral microorganisms. The contents of phenolic compounds were investigated. Cytotoxic potential was evaluated on oral fibroblasts after 1-5 min exposure to BFLT. Blocks of sound bovine enamel (N = 60) were inoculated with a saliva pool and sustained in a multiple plaque growth system for 48 h to form a biofilm. Biofilm blocks were randomly divided into groups-G (n = 10): G1-Baseline (48 h maturation biofilm), G2-BFLT 23.2 mg/mL, G3-Ethanol 81.20 g/mL, G4-Chlorhexidine 0.12%, G5-Growth control, and G6-Blank control. Treatments (50 μL/1 min) were performed once a day for a week. Streptococcus spp. (S) and total microorganism (TM) counts were expressed as Log10 CFU/mL. Biofilm height was evaluated by confocal microscopy analyses (CMA). Final surface hardness was assessed and percentage of microhardness loss (% MHL) was calculated. Results were significant when P < .05. BFLT inhibited all tested microorganisms (MIC = 1.3-23.2 mg/mL) and promoted optical reduction (0.05-0.22 nm) of all microorganisms after 48-h treatment compared with controls. After 5-min treatment, BFLT showed low values of cell death (3.20%). G2-BFLT reduced S (6.61 ± 0.20) and TM (7.14 ± 0.38) compared with G1-Baseline (S = 7.82 ± 0.28; TM = 8.81 ± 0.67) and G5-Growth control (S = 7.48 ± 0.39; TM = 7.89 ± 0.68); but G4-chlororexidine (S = 6.11 ± 0.48; TM = 6.45 ± 0.16) showed the highest antibiofilm activity. CMA was not different among treatment groups. G2 showed lower % MHL compared with G5, although G4 presented the lowest. Results suggest BFLT is beneficial against dental caries, showing antimicrobial effects against a mature dental biofilm and no cytotoxicity.}, } @article {pmid31998794, year = {2020}, author = {Liu, X and Wang, J and Weng, CX and Wang, R and Cai, Y}, title = {Low-Frequency Ultrasound Enhances Bactericidal Activity of Antimicrobial Agents against Klebsiella pneumoniae Biofilm.}, journal = {BioMed research international}, volume = {2020}, number = {}, pages = {5916260}, pmid = {31998794}, issn = {2314-6141}, mesh = {Biofilms/*growth & development ; Klebsiella pneumoniae/*physiology ; *Ultrasonic Waves ; }, abstract = {Klebsiella pneumoniae biofilms on inserted devices have been proposed as one of the important factors for hospital-acquired infections, which cause increased resistance to currently used antibiotics. Therefore, it is urgently necessary to develop new treatments with more efficient bacterial clearance. In the present study, we aimed at investigating whether low-frequency ultrasound (LFU) could enhance the bactericidal activity of antimicrobial agents (meropenem (MEM), tigecycline (TGC), fosfomycin (FOM), amikacin (AMK), and colistin (COL)) against K. pneumoniae biofilm infection. K. pneumoniae biofilm was cultivated on the catheter in vitro. Synergistic effects were observed in groups of single ultrasound (S-LFU, 5 min) or multiple ultrasound (M-LFU, 5 min every 8 h (q8h)) in combination with MEM, TGC, and FOM. However, AMK and COL did not show the synergistic effect with either S-LFU or M-LFU. S-LFU in combination with FOM only significantly decreased bacterial counts right after ultrasound, while M-LFU could prolong the synergistic effect until 24 h. The results showed that LFU in combination with antimicrobial agents had a synergistic effect on K. pneumoniae biofilm, and M-LFU might extend the time of synergistic effect compared with S-LFU.}, } @article {pmid31998455, year = {2019}, author = {Shivaee, A and Sadeghi Kalani, B and Talebi, M and Darban-Sarokhalil, D}, title = {Does biofilm formation have different pathways in Staphylococcus aureus?.}, journal = {Iranian journal of basic medical sciences}, volume = {22}, number = {10}, pages = {1147-1152}, pmid = {31998455}, issn = {2008-3866}, abstract = {OBJECTIVES: Biofilm formation is one of the most important factors in the development of infections caused by Staphylococcus aureus. In this study, the expression levels of genes responsible for biofilm formation were studied in methicillin sensitive and methicillin resistant S. aureus.

MATERIALS AND METHODS: A total of 100 meticillin-resistant s.aureus (MRSA) and meticillin-sensetive s.aureus (MSSA) isolates were studied. Bacterial biofilm formation was evaluated phenotypically using microtiter plate method. Real-time PCR tests were conducted to determine the expression levels of genes involved in biofilm formation.

RESULTS: Quantitative biofilm formation test was repeated three times for each specimen. The prevalence of weak, medium, and strong biofilm producers were 16%, 49%, and 35%, respectively. In MSSA isolates, expression levels of ica genes increased compared to the fnbA, fnbB, clfA and clfB genes. These results were different in MRSA isolates, and ica genes showed a decreased gene expression levels compared to the aforementioned genes.

CONCLUSION: Considering the results of this study, clf genes probably contribute to the same extent in both MRSA and MSSA isolates, and there is probably no significant difference in the role of these genes in these isolates. In addition, the results of this study indicated that MRSA may not use the conventional route for biofilm formation and may use independent pathways through Polysaccharide intercellular adhesion (PIA).}, } @article {pmid31998344, year = {2019}, author = {Park, H and Do, E and Kim, M and Park, HJ and Lee, J and Han, SW}, title = {A LysR-Type Transcriptional Regulator LcrX Is Involved in Virulence, Biofilm Formation, Swimming Motility, Siderophore Secretion, and Growth in Sugar Sources in Xanthomonas axonopodis Pv. glycines.}, journal = {Frontiers in plant science}, volume = {10}, number = {}, pages = {1657}, pmid = {31998344}, issn = {1664-462X}, abstract = {Xanthomonas axonopodis pv. glycines (Xag) is a Gram-negative bacterium that causes bacterial pustule disease in soybean. To acclimate to new environments, the expression of genes in bacteria is controlled directly or indirectly by diverse transcriptional factors. Among them, LysR type transcriptional regulators are well-characterized and abundant in bacteria. In a previous study, comparative proteomic analysis revealed that LysR type carbohydrate-related transcriptional regulator in Xag (LcrX) was more abundant in XVM2, which is a minimal medium, compared with a rich medium. However, the functions of LcrX in Xag have not been characterized. In this study, we generated an LcrX-overexpressing strain, Xag(LcrX), and the knockout mutant strain, XagΔlcrX(EV), to elucidate the functions of LcrX. Bacterial multiplication of Xag(LcrX) in soybean was significantly impaired, indicating that LcrX is related to virulence. Comparative proteomic analysis revealed that LcrX is mainly involved in carbohydrate metabolism/transport and inorganic ion transport/metabolism. Based on the results of proteomics analysis, diverse phenotypic assays were carried out. A gel electrophoresis mobility shift assay demonstrated that LcrX specifically bound to the putative promoter regions of genes encoding putative fructose 1,6-bisphosphatase and protease. Through a 96-well plate assay under various conditions, we confirmed that the growth of Xag(LcrX) was dramatically affected in the presence of various carbon sources, while the growth of XagΔlcrX(EV) was only slightly changed. Biofilm formation activity was reduced in Xag(LcrX) but enhanced in XagΔlcrX(EV). The production of siderophores was also decreased in Xag(LcrX) but not altered in XagΔlcrX(EV). In contrast, LcrX was not associated with exopolysaccharide production, protease activity, or bacterial motility. These findings provide new insights into the functions of a carbohydrate-related transcriptional regulator in Xag.}, } @article {pmid31998248, year = {2019}, author = {Olivares, E and Badel-Berchoux, S and Provot, C and Prévost, G and Bernardi, T and Jehl, F}, title = {Clinical Impact of Antibiotics for the Treatment of Pseudomonas aeruginosa Biofilm Infections.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2894}, pmid = {31998248}, issn = {1664-302X}, abstract = {Bacterial biofilms are highly recalcitrant to antibiotic therapies due to multiple tolerance mechanisms. The involvement of Pseudomonas aeruginosa in a wide range of biofilm-related infections often leads to treatment failures. Indeed, few current antimicrobial molecules are still effective on tolerant sessile cells. In contrast, studies increasingly showed that conventional antibiotics can, at low concentrations, induce a phenotype change in bacteria and consequently, the biofilm formation. Understanding the clinical effects of antimicrobials on biofilm establishment is essential to avoid the use of inappropriate treatments in the case of biofilm infections. This article reviews the current knowledge about bacterial growth within a biofilm and the preventive or inducer impact of standard antimicrobials on its formation by P. aeruginosa. The effect of antibiotics used to treat biofilms of other bacterial species, as Staphylococcus aureus or Escherichia coli, was also briefly mentioned. Finally, it describes two in vitro devices which could potentially be used as antibiotic susceptibility testing for adherent bacteria.}, } @article {pmid31997661, year = {2020}, author = {Gomes, IB and Simões, LC and Simões, M}, title = {Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress.}, journal = {Biofouling}, volume = {36}, number = {1}, pages = {1-13}, doi = {10.1080/08927014.2019.1708334}, pmid = {31997661}, issn = {1029-2454}, mesh = {Biofilms/*drug effects/growth & development ; Chlorine/*pharmacology ; Copper/*pharmacology ; Halogenation ; Models, Theoretical ; Stenotrophomonas maltophilia/*drug effects/growth & development ; *Stress, Mechanical ; Surface Properties ; Water Microbiology ; Water Purification ; }, abstract = {This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg l[-1] of free chlorine for 10 min, an increased shear stress (a fluid velocity of 1.5 m s[-1] for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.}, } @article {pmid31997643, year = {2020}, author = {Romeu, MJ and Rodrigues, D and Azeredo, J}, title = {Effect of sub-lethal chemical disinfection on the biofilm forming ability, resistance to antibiotics and expression of virulence genes of Salmonella Enteritidis biofilm-surviving cells.}, journal = {Biofouling}, volume = {36}, number = {1}, pages = {101-112}, doi = {10.1080/08927014.2020.1719077}, pmid = {31997643}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Benzalkonium Compounds/pharmacology ; Biofilms/*drug effects/growth & development ; Disinfectants/*pharmacology ; Disinfection/*methods ; Drug Resistance, Bacterial/*drug effects/genetics ; Gene Expression/drug effects ; Genes, Bacterial/drug effects ; Salmonella enteritidis/*drug effects/genetics/growth & development/pathogenicity ; Sodium Hypochlorite/pharmacology ; *Virulence/drug effects/genetics ; }, abstract = {Although disinfection procedures are widely implemented in food environments, bacteria can survive and present increased virulence/resistance. Since little is known about these phenomena regarding biofilms, this study aimed to investigate the effect of chemical disinfection on biofilm-derived cells of Salmonella Enteritidis. Using a reference strain (NCTC 13349) and a food isolate (350), biofilm susceptibility to benzalkonium chloride (BAC), sodium hypochlorite (SH) and hydrogen peroxide (HP) was evaluated and biofilms were exposed to sub-lethal concentrations of each disinfectant. Biofilm-derived cells were characterized for their biofilm forming ability, antibiotic resistance and expression of virulence-associated genes. Except for a few instances, disinfectant exposure did not alter antibiotic susceptibility. However, SH and HP exposure enhanced the biofilm forming ability of Salmonella Enteritidis NCTC 13349. After BAC and HP exposure, biofilm-derived cells presented a down-regulation of rpoS. Exposure to BAC also revealed an up-regulation of invA, avrA and csgD on Salmonella Enteritidis NCTC 13349. The results obtained suggest that biofilm-derived cells that survive disinfection may represent an increased health risk.}, } @article {pmid31997572, year = {2020}, author = {Okshevsky, M and Gautier, E and Farner, JM and Schreiber, L and Tufenkji, N}, title = {Biofilm formation by marine bacteria is impacted by concentration and surface functionalization of polystyrene nanoparticles in a species-specific manner.}, journal = {Environmental microbiology reports}, volume = {12}, number = {2}, pages = {203-213}, doi = {10.1111/1758-2229.12824}, pmid = {31997572}, issn = {1758-2229}, support = {//Canada Foundation for Innovation/International ; //Canada Research Chairs/International ; //Natural Sciences and Engineering Research Council of Canada/International ; }, mesh = {Aquatic Organisms/drug effects/growth & development ; *Bacteria/drug effects/growth & development ; *Biofilms/drug effects/growth & development ; Nanoparticles ; Oceans and Seas ; Plastics/chemistry/pharmacology ; Polystyrenes/*pharmacology ; Seawater/microbiology ; *Water Pollutants/chemistry/pharmacology ; }, abstract = {The world's oceans are becoming increasingly polluted by plastic waste. In the marine environment, larger plastic pieces may degrade into nanoscale (<100 nm in at least one dimension) plastic particles due to natural weathering effects. We observe that the presence of 20 nm plastic nanoparticles at concentrations below 200 ppm had no impact on planktonic growth of a panel of heterotrophic marine bacteria. However, the presence of plastic nanoparticles significantly impacted the formation of biofilms in a species-specific manner. While carboxylated nanoparticles increased the amount of biofilm formed by several species, amidine-functionalized nanoparticles decreased the amount of biofilm of many but not all bacteria. Further experiments suggested that the aggregation dynamics of bacteria and nanoparticles were strongly impacted by the surface properties of the nanoparticles. The community structure of an artificially constructed community of marine bacteria was significantly altered by exposure to plastic nanoparticles, with differently functionalized nanoparticles selecting for unique and reproducible community abundance patterns. These results suggest that surface properties and concentration of plastic nanoparticles, as well as species interactions, are important factors determining how plastic nanoparticles impact biofilm formation by marine bacteria.}, } @article {pmid31996786, year = {2020}, author = {Reiner, JE and Geiger, K and Hackbarth, M and Fink, M and Lapp, CJ and Jung, T and Dötsch, A and Hügler, M and Wagner, M and Hille-Reichel, A and Wilcke, W and Kerzenmacher, S and Horn, H and Gescher, J}, title = {From an extremophilic community to an electroautotrophic production strain: identifying a novel Knallgas bacterium as cathodic biofilm biocatalyst.}, journal = {The ISME journal}, volume = {14}, number = {5}, pages = {1125-1140}, pmid = {31996786}, issn = {1751-7370}, mesh = {Autotrophic Processes ; Bacillales/*physiology ; Bacteria/metabolism ; Biofilms/*growth & development ; Carbon Dioxide/metabolism ; Electrodes ; Extremophiles/metabolism/*physiology ; Hydrogenase/metabolism ; }, abstract = {Coupling microbial electrosynthesis to renewable energy sources can provide a promising future technology for carbon dioxide conversion. However, this technology suffers from a limited number of suitable biocatalysts, resulting in a narrow product range. Here, we present the characterization of the first thermoacidophilic electroautotrophic community using chronoamperometric, metagenomic, and [13]C-labeling analyses. The cathodic biofilm showed current consumption of up to -80 µA cm[-2] over a period of 90 days (-350 mV vs. SHE). Metagenomic analyses identified members of the genera Moorella, Desulfofundulus, Thermodesulfitimonas, Sulfolobus, and Acidianus as potential primary producers of the biofilm, potentially thriving via an interspecies sulfur cycle. Hydrogenases seem to be key for cathodic electron uptake. An isolation campaign led to a pure culture of a Knallgas bacterium from this community. Growth of this organism on cathodes led to increasing reductive currents over time. Transcriptomic analyses revealed a distinct gene expression profile of cells grown at a cathode. Moreover, pressurizable flow cells combined with optical coherence tomography allowed an in situ observation of cathodic biofilm growth. Autotrophic growth was confirmed via isotope analysis. As a natural polyhydroxybutyrate (PHB) producer, this novel species, Kyrpidia spormannii, coupled the production of PHB to CO2 fixation on cathode surfaces.}, } @article {pmid31996524, year = {2020}, author = {Li, YY and Li, BS and Liu, WW and Cai, Q and Wang, HY and Liu, YQ and Liu, YJ and Meng, WY}, title = {Effects of D-arginine on Porphyromonas gingivalis biofilm.}, journal = {Journal of oral science}, volume = {62}, number = {1}, pages = {57-61}, doi = {10.2334/josnusd.19-0075}, pmid = {31996524}, issn = {1880-4926}, mesh = {Arginine ; Biofilms ; Humans ; Microscopy, Electron, Scanning ; *Peri-Implantitis ; *Porphyromonas gingivalis ; }, abstract = {Porphyromonas gingivalis (P. gingivalis) is one of the major pathogenic bacteria of periodontitis or peri-implantitis. P. gingivalis tends to attach to the implant's neck with the formation of biofilm, leading to peri-implantitis. d-arginine has been shown to have a potential antimicrobial role. In this study, P. gingivalis was cultured in Brain Heart Infusion broth together with d-arginine. After 3 days (inhibition) or 6 days (dissociation), these were characterized using crystal violet (CV) staining for the biofilm, extracellular polysaccharide (EPS) production from the biofilm, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for biofilm activation. Furthermore, the P. gingivalis biofilm was observed by scanning electron microscopy (SEM). d-arginine effectively reduced biomass accumulation and promoted dissociation at concentrations of ≥50 mM and 100 mM, respectively. Through CV staining, d-arginine concentrations of EPS production from the biofilm for inhibition and dissociation effects was ≥50 mM and 100 mM, respectively. In addition, d-arginine affected biofilm activation for the corresponding concentrations: ≥60 mM for inhibition and ≥90 mM for dispersal. Under SEM observation, d-arginine changed the P. gingivalis biofilm structure in relatively high concentrations for inhibition or dissociation, respectively. The authors concluded that d-arginine could inhibit the formation of P. gingivalis biofilm and promote the dissociation of P. gingivalis biofilm.}, } @article {pmid31996322, year = {2020}, author = {Ahmadi, H and Haddadi-Asl, V and Ghafari, HA and Ghorbanzadeh, R and Mazlum, Y and Bahador, A}, title = {Shear bond strength, adhesive remnant index, and anti-biofilm effects of a photoexcited modified orthodontic adhesive containing curcumin doped poly lactic-co-glycolic acid nanoparticles: An ex-vivo biofilm model of S. mutans on the enamel slab bonded brackets.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {30}, number = {}, pages = {101674}, doi = {10.1016/j.pdpdt.2020.101674}, pmid = {31996322}, issn = {1873-1597}, mesh = {Adhesives ; Biofilms ; *Curcumin/pharmacology ; Dental Enamel ; Glycolates ; Glycols ; Materials Testing ; *Nanoparticles ; *Orthodontic Brackets ; *Photochemotherapy/methods ; Photosensitizing Agents ; }, abstract = {BACKGROUND: Potential complications during fixed orthodontic procedures are white spot lesions (WSLs) and tooth decay. This study evaluated the anti-biofilm activity of an orthodontic adhesive (OA) incorporating curcumin (Cur) doped Poly lactic-co-glycolic acid nanoparticles (Cur-PLGA-NPs), which can have the highest concentration of Cur-PLGA-NPs and shear bond strength (SBS) value simultaneously, against cariogenic bacteria i.e., Streptococcus mutans.

MATERIALS AND METHODS: Following synthesis and confirmation of Cur-PLGA-NPs, SBS and adhesive remnant index (ARI) of the modified orthodontic adhesives (MOA) containing Cur-PLGA-NPs (3, 5, 7, and 10 % wt.) were measured using universal testing machine and stereomicroscope, respectively. After artificial aging (continuously rinsed up to 180 days), the residual anti-biofilm ability of MOA which can have the highest concentration of Cur-PLGA-NPs and SBS value simultaneously were determined by anti-biofilm assay following photoexcited enamel slab bonded brackets by MOA containing Cur-PLGA-NPs against S. mutans biofilms using crystal violet assay.

RESULTS: Adhesive with 7 % wt. Cur-PLGA-NPs revealed the highest concentration of Cur-PLGA-NPs and SBS value (16.19 ± 2.69 MPa, P < 0.05) simultaneously. No statistically significant difference in ARI scores was observed between the MOA and control (Transbond XT without the Cur-PLGA-NPs). On days 15, 30, 60, 90 and 120 there was a considerable decrease in optical density (OD) of preformed S. mutans biofilms on photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs, to 94.1 %, 79.6 %, 69.6 %, 69.4 %, and, 55.1 % respectively in comparison to the control group (all, P < 0.05). From days 150 onwards, microbial biofilm formation was progressively increased on enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs compared to the control group (OA). Although chlorhexidine (2 %; as positive control) showed significant activity against pre-formed S. mutans biofilms on enamel slab bonded brackets using OA (99.1 % biofilm reduction; P = 0.001), its activity was slightly higher but not significant than photoexcited enamel slab bonded brackets using MOA containing 7 % wt. Cur-PLGA-NPs on the days 15 and 30 (both, P > 0.05).

CONCLUSIONS: The 7 % wt. Cur-PLGA-NPs can serve as an orthodontic adhesive antimicrobial additive as exposure to blue laser provides an acceptable antimicrobial effect against cariogenic bacteria for a considerable time.}, } @article {pmid31994719, year = {2020}, author = {Yuan, S and Meng, F}, title = {Ecological insights into the underlying evolutionary patterns of biofilm formation from biological wastewater treatment systems: Red or Black Queen Hypothesis?.}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {5}, pages = {1270-1280}, doi = {10.1002/bit.27289}, pmid = {31994719}, issn = {1097-0290}, support = {2017YFE0114300//National Key R&D Program of China/International ; 51622813 and 51878675//National Natural Science Foundation of China/International ; 2017B020216006 and 2015A020215014//Science and Technology Planning Project of Guangdong Province/International ; }, mesh = {*Biofilms ; *Biological Evolution ; Bioreactors ; Microbial Interactions ; *Models, Biological ; Sewage/*microbiology ; *Water Purification ; }, abstract = {Interspecies interactions and phylogenetic distances were studied to reveal the underlying evolutionary adaptations of biofilms sourced from wastewater treatment processes. Based on 380 pairwise cocultures of 40 strains from two microbial aggregates (surface-attached and mobile aggregates [flocs]) at two substrate concentrations (LB broth and 0.1× LB broth), interspecies interactions were explored using biofilm classification schemes. There was a strong source-dependence of biofilm development formed by the monocultures, that is, a higher biofilm formation potential for strains from attached aggregates than for those from sludge flocs at both substrate concentrations. Interestingly, the results showed that total biofilm reduction was dominant in the dual-species biofilm sourced from flocs in both LB broth (67.37%) and 0.1× LB broth (64.21%), indicating high interspecific competition in mobile aggregates and the independence of substrate concentrations. However, biofilm reduction was higher (33.68%) than induction (19.37%) for the biofilms formed by surface-attached aggregates in LB broth, while the opposite trend was apparent in 0.1× LB broth, suggesting the occurrence of indeterministic processes for biofilm formation and important roles of substrate concentrations. In addition, the more closely related phylogenetic relationships of cocultures from mobile aggregates were consistent with higher competition compared with those from surface-attached aggregates. Overall, the underlying evolutionary patterns of biofilms formed from mobile aggregates consistently followed the essence of the "Red Queen Hypothesis," while biofilms developed from surface-attached aggregates were not deterministic. This study advanced our understanding of biofilm-related treatment processes using the principles of microbial ecology.}, } @article {pmid31993211, year = {2020}, author = {Alves, R and Kastora, SL and Gomes-Gonçalves, A and Azevedo, N and Rodrigues, CF and Silva, S and Demuyser, L and Van Dijck, P and Casal, M and Brown, AJP and Henriques, M and Paiva, S}, title = {Transcriptional responses of Candida glabrata biofilm cells to fluconazole are modulated by the carbon source.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {}, pages = {4}, pmid = {31993211}, issn = {2055-5008}, support = {MR/M026663/1/MRC_/Medical Research Council/United Kingdom ; MR/N006364/1/MRC_/Medical Research Council/United Kingdom ; MR/N006364/2/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Candida glabrata/drug effects/*physiology ; Carbon/*metabolism ; Drug Resistance, Fungal ; Fluconazole/*pharmacology ; Fungal Proteins/*genetics ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Fungal/drug effects ; Hydrogen-Ion Concentration ; Metabolic Flux Analysis ; Sequence Analysis, RNA ; Virulence Factors/genetics ; Exome Sequencing ; }, abstract = {Candida glabrata is an important human fungal pathogen known to trigger serious infections in immune-compromised individuals. Its ability to form biofilms, which exhibit high tolerance to antifungal treatments, has been considered as an important virulence factor. However, the mechanisms involving antifungal resistance in biofilms and the impact of host niche environments on these processes are still poorly defined. In this study, we performed a whole-transcriptome analysis of C. glabrata biofilm cells exposed to different environmental conditions and constraints in order to identify the molecular pathways involved in fluconazole resistance and understand how acidic pH niches, associated with the presence of acetic acid, are able to modulate these responses. We show that fluconazole treatment induces gene expression reprogramming in a carbon source and pH-dependent manner. This is particularly relevant for a set of genes involved in DNA replication, ergosterol, and ubiquinone biosynthesis. We also provide additional evidence that the loss of mitochondrial function is associated with fluconazole resistance, independently of the growth condition. Lastly, we propose that C. glabrata Mge1, a cochaperone involved in iron metabolism and protein import into the mitochondria, is a key regulator of fluconazole susceptibility during carbon and pH adaptation by reducing the metabolic flux towards toxic sterol formation. These new findings suggest that different host microenvironments influence directly the physiology of C. glabrata, with implications on how this pathogen responds to antifungal treatment. Our analyses identify several pathways that can be targeted and will potentially prove to be useful for developing new antifungals to treat biofilm-based infections.}, } @article {pmid31992930, year = {2020}, author = {Douthit, C and Gudenkauf, B and Hamood, A and Mudaliar, N and Caroom, C and Jenkins, M}, title = {Effects of powdered rifampin and vancomycin solutions on biofilm production of staphylococcus aureus on orthopedic implants.}, journal = {Journal of clinical orthopaedics and trauma}, volume = {11}, number = {Suppl 1}, pages = {S113-S117}, pmid = {31992930}, issn = {0976-5662}, abstract = {PURPOSE: Hardware infections in orthopedic surgery, specifically those involving biofilm producing bacteria, are troublesome and are highly resistant to systemic antibiotics. The purpose of this study was to demonstrate the power of rifampin and vancomycin solutions in inhibiting as well as eliminating in vitro on staphylococcus aureus (S. aureus) biofilm in vitro on stainless-steel implants.

METHODS: A suspension of either S. aureus or a S. aureus containing a plasmid that cods for the green fluorescence protein containing fluorescent protein plasmid was applied to 1 × 1cm sterile stainless steel orthopedic plating material (coupon). Biofilm development was confirmed by; the quantitative assay (colony forming unit [CFU/coupon]) and visualized using confocal laser scanning microscopy. With this established method of biofilm development, we determined the minimum biofilm inhibitory concentration (MBIC) and the minimum biofilm eradication concertation (MBEC) of Rifampicin and Vancomycin. To determine the MBIC, stainless steel plates were subjected to different concentrations of antibiotic solution and inoculated with overnight cultures of S. aureus. After 24 h of incubation at 37 °C, the biofilms on the untreated and antibiotic-treated coupons were quantified. To determine the MBEC, partial S. aureus biofilms were developed on the coupons and then treated with the different concentrations of each antibiotic for 24 h. The number of bacteria within the control untreated as well as treated coupons was determined.

RESULTS: Both rifampin and vancomycin solutions inhibited biofilm production of S. aureus on stainless steel mediums; the MBIC for rifampin and vancomycin were 80 ng/mL and 1 μg/mL respectively. The MBEC for Rifampicin was similar to the MBIC. However, the MBEC for Vancomycin was 6 mg/ml.

CONCLUSIONS: When applied to orthopedic stainless steel hardware in vitro, solutions of rifampin and vancomycin powder separately or in combination can completely prevent and eliminate biofilm produced by S. aureus.

LEVEL OF EVIDENCE: II.}, } @article {pmid31991823, year = {2020}, author = {Speranza, B and Liso, A and Russo, V and Corbo, MR}, title = {Evaluation of the Potential of Biofilm Formation of Bifidobacterium longum subsp. infantis and Lactobacillus reuteri as Competitive Biocontrol Agents Against Pathogenic and Food Spoilage Bacteria.}, journal = {Microorganisms}, volume = {8}, number = {2}, pages = {}, pmid = {31991823}, issn = {2076-2607}, abstract = {This study proposes to exploit the in vivo metabolism of two probiotics (Bifidobacterium longum subsp. infantis and Lactobacillus reuteri) which, upon adhesion on a solid surface, form a biofilm able to control the growth of pathogenic and food spoilage bacteria. The results showed that pathogenic cell loads were always lower in presence of biofilm (6.5-7 log CFU/cm[2]) compared to those observed in its absence. For Escherichia coli O157:H7, a significant decrease (>1-2 logarithmic cycles) was recorded; for Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica, cell load reductions ranged from 0.5 to 1.5 logarithmic cycles. When tested as active packaging, the biofilm was successfully formed on polypropylene, polyvinyl chloride, greaseproof paper, polyethylene and ceramic; the sessile cellular load ranged from 5.77 log CFU/cm[2] (grease-proof paper) to 6.94 log CFU/cm[2] (polyethylene, PE). To test the potential for controlling the growth of spoilage microorganisms in food, soft cheeses were produced, inoculated with L. monocytogenes and Pseudomonas fluorescens, wrapped in PE pellicles with pre-formed biofim, packed both in air and under vacuum, and stored at 4 and 15 °C: an effective effect of biofilms in slowing the decay of the microbiological quality was recorded.}, } @article {pmid31991024, year = {2020}, author = {Pomaranski, EK and Soto, E}, title = {The Formation, Persistence, and Resistance to Disinfectant of the Erysipelothrix piscisicarius Biofilm.}, journal = {Journal of aquatic animal health}, volume = {32}, number = {1}, pages = {44-49}, doi = {10.1002/aah.10097}, pmid = {31991024}, issn = {1548-8667}, mesh = {Aquaculture ; Biofilms/*drug effects/growth & development ; Disinfectants/*administration & dosage ; Dose-Response Relationship, Drug ; *Drug Resistance, Bacterial ; Durapatite ; Erysipelothrix/*drug effects/growth & development/physiology ; Erysipelothrix Infections/*prevention & control ; Hydrogen Peroxide/administration & dosage ; Peroxides/administration & dosage ; Sodium Hypochlorite/administration & dosage ; Sulfuric Acids/administration & dosage ; }, abstract = {Erysipelothrix piscisicarius is an emergent pathogen in fish aquaculture, particularly in the ornamental fish trade. Very little is known on the biology of this pathogen; however, the recurrence of infection and disease outbreaks after removing the fish from a system and disinfecting the tank suggest its environmental persistence. Moreover, biofilm lifestyle in E. piscisicarius has been suspected but not previously shown. The purpose of this study was to investigate the formation of biofilms on an abiotic surface in Erysipelothrix spp. We used hydroxyapatite-coated plastic pegs to demonstrate the attachment, growth, and persistence of E. piscisicarius on abiotic surfaces in both fresh and marine environments and to investigate the susceptibility of this pathogen to different disinfectants that are used in the aquaculture industry. E. piscisicarius formed biofilms that persisted significantly longer than planktonic cells did in both freshwater and saltwater over a period of 120 h (P = 0.004). The biofilms were also more resistant to disinfectants than the planktonic cells were. Hydrogen peroxide was the most effective disinfectant against E. piscisicarius, and it eradicated the biofilms and planktonic cells at the recommended concentrations. In contrast, Virkon and bleach were able to eradicate only the planktonic cells. This information should be taken into consideration when developing biosecurity protocols in aquaculture systems, aquariums, and private collections.}, } @article {pmid31989544, year = {2020}, author = {Kim, AR and Kang, M and Yoo, YJ and Yun, CH and Perinpanayagam, H and Kum, KY and Han, SH}, title = {Lactobacillus plantarum lipoteichoic acid disrupts mature Enterococcus faecalis biofilm.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {58}, number = {4}, pages = {314-319}, pmid = {31989544}, issn = {1976-3794}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bicuspid/microbiology ; Biofilms/*drug effects ; Calcium Hydroxide/therapeutic use ; Chlorhexidine/analogs & derivatives/therapeutic use ; Dentin/*microbiology ; Enterococcus faecalis/*drug effects ; Gram-Positive Bacterial Infections/therapy ; Humans ; Lactobacillus plantarum/metabolism ; Lipopolysaccharides/*pharmacology ; Periapical Periodontitis/therapy ; Teichoic Acids/*pharmacology ; }, abstract = {Apical periodontitis is caused by biofilm-mediated root canal infection. Early phase oral bacterial biofilms are inhibited by Lactobacillus plantarum lipoteichoic acid (Lp.LTA). However, mature biofilms that develop over 3 weeks are more resistant to traditional endodontic medicaments. Therefore, this study examined the effectiveness of Lp.LTA on disrupting mature Enterococcus faecalis biofilms, and on enhancing the effects of endodontic medicaments. LTA was purified from L. plantarum through butanol extraction followed by hydrophobic and ion-exchange chromatography. E. faecalis biofilms were formed over 3 weeks on glass bottom dishes and in dentin blocks obtained from human single-rooted premolars. These mature biofilms were treated with or without Lp.LTA for 1 h, followed by additional treatment with either chlorhexidine digluconate (CHX), calcium hydroxide (CH), or triple antibiotics for 24 h. Biofilms on glass were live/dead stained and quantified by ZEN through confocal laser microscopy. Bio-films in dentin were fixed, sputter coated and analyzed by ImageJ with scanning electron microscopy. Preformed E. faecalis mature biofilms on the culture dishes were dose-dependently disrupted by Lp.LTA. Lp.LTA potentiated the effects of CHX or CH on the disruption of mature biofilm. Interestingly, CHX-induced disruption of preformed E. faecalis mature biofilms was synergistically enhanced only when pre-treated with Lp.LTA. Furthermore, in the dentin block model, Lp.LTA alone reduced E. faecalis mature biofilm and pre-treatment with Lp.LTA promoted the anti-biofilm activity of CHX. Lp.LTA could be an anti-biofilm or supplementary agent that can be effective for E. faecalis-biofilm-induced diseases.}, } @article {pmid31989448, year = {2020}, author = {Algburi, A and Alazzawi, SA and Al-Ezzy, AIA and Weeks, R and Chistyakov, V and Chikindas, ML}, title = {Potential Probiotics Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Co-Aggregate with Clinical Isolates of Proteus mirabilis and Prevent Biofilm Formation.}, journal = {Probiotics and antimicrobial proteins}, volume = {12}, number = {4}, pages = {1471-1483}, doi = {10.1007/s12602-020-09631-0}, pmid = {31989448}, issn = {1867-1314}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacillus amyloliquefaciens/*chemistry/physiology ; Bacillus subtilis/*chemistry/physiology ; Bacterial Adhesion/drug effects ; Bacteriocins/biosynthesis/isolation & purification/pharmacology ; Biofilms/*drug effects/growth & development ; Culture Media, Conditioned/chemistry/pharmacology ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Peptides, Cyclic/biosynthesis/isolation & purification/pharmacology ; Probiotics/chemistry/*pharmacology ; Proteus Infections/microbiology/pathology ; Proteus mirabilis/*drug effects/isolation & purification/pathogenicity ; Sheep ; Sheep Diseases/microbiology/pathology ; Urinary Tract Infections/microbiology/pathology ; }, abstract = {A urinary tract infection (UTI) is a multi-factorial disease including cystitis, pyelonephritis, and pyelitis. After Escherichia coli, Proteus mirabilis is the most common UTI-associated opportunistic pathogen. Antibiotic resistance of bacteria and infection recurrence can be connected to biofilm formation by P. mirabilis. In this study, human and sheep isolates of P. mirabilis were investigated for antibiotic sensitivity using an antibiotic disk test. Co-aggregation of the tested potential probiotic bacilli, Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933, with the isolated pathogen was also evaluated. Then, the anti-biofilm activity of naturally derived metabolites, such as subtilin and subtilosin, in the bacilli-free supernatants was assessed against biofilms of P. mirabilis isolates. The isolated pathogens were sensitive to 30 μg of amikacin and 5 μg of ciprofloxacin but resistant to other tested antibiotics. After 24 h, auto-aggregation of B. amyloliquefaciens B-1895 was at 89.5% and higher than auto-aggregation of B. subtilis KATMIRA1933 (59.5%). B. amyloliquefaciens B-1895 strongly co-aggregated with P. mirabilis isolates from human UTIs. Cell-free supernatants of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 showed higher antimicrobial activity against biofilms of P. mirabilis isolated from humans as compared with biofilms of sheep isolates. According to our knowledge, this is the first report evaluating the anti-biofilm activity of probiotic spore-forming bacilli against clinical and animal UTI isolates of P. mirabilis. Further studies are recommended to investigate the anti-biofilm activity and the mode of action for the antimicrobial substances produced by these bacilli, subtilosin and subtilin.}, } @article {pmid31987843, year = {2020}, author = {Herruzo, R and Herruzo, I}, title = {Antimicrobial efficacy of a very stable hypochlorous acid formula compared with other antiseptics used in treating wounds: in-vitro study on micro-organisms with or without biofilm.}, journal = {The Journal of hospital infection}, volume = {105}, number = {2}, pages = {289-294}, doi = {10.1016/j.jhin.2020.01.013}, pmid = {31987843}, issn = {1532-2939}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Anti-Infective Agents, Local/classification/*pharmacology ; Bacteria/classification/*drug effects ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Humans ; Hypochlorous Acid/chemistry/*pharmacology ; Mucous Membrane/drug effects/microbiology ; Skin/drug effects/microbiology ; Wounds and Injuries/microbiology ; Yeasts/*drug effects ; }, abstract = {BACKGROUND: Many antiseptics have been used to treat wounds.

AIM: To compare the microbicidal efficacy of ClHO (Clortech®) with other antiseptics used on wounds, healthy skin and mucous membranes.

METHODS: The microbicidal efficacy of 13 antiseptic products on eight micro-organisms (three Gram-positive; three Gram-negative; two yeasts) inoculated on organic germ-carriers was studied. In addition, the loss of efficacy against Staphylococcus aureus and Pseudomonas aeruginosa with biofilm was assessed with the six best-performing products.

FINDINGS: Chlorhexidine (1%) had the highest microbicidal effect at 1 min. At 5 min, 500 and 1500 mg/L ClHO showed similar, or better, activity than the other antiseptics studied. The ClHO concentration of 300 mg/L achieved this same efficacy at 10 min. The product that lost the most efficacy due to biofilm was 1% chlorhexidine, while 1% PVP-I and ClHO at either 300 or 500 mg/L were moderately affected by biofilm. The most effective in the presence of biofilm was ClHO at 1500 mg/L.

CONCLUSIONS: ClHO at medium-low concentrations (300 or 500 mg/L) is a good antiseptic that can be used on wounds and mucous membranes for 5-10 min. Lower concentrations of ClHO, as well as of the other antiseptics studied, were less effective or more altered by the biofilm. ClHO at a concentration of 1500 mg/L is very effective in the presence or absence of biofilm that can be used on healthy skin for 5 min.}, } @article {pmid31986930, year = {2020}, author = {Pijls, BG and Sanders, IMJG and Kuijper, EJ and Nelissen, RGHH}, title = {Synergy between induction heating, antibiotics, and N-acetylcysteine eradicates Staphylococcus aureus from biofilm.}, journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group}, volume = {37}, number = {1}, pages = {130-136}, doi = {10.1080/02656736.2019.1710269}, pmid = {31986930}, issn = {1464-5157}, mesh = {Acetylcysteine/*metabolism ; Anti-Bacterial Agents/pharmacology/*therapeutic use ; Biofilms/*drug effects ; Heating/*methods ; Humans ; Staphylococcus aureus/*drug effects ; }, abstract = {Background: Non-contact induction heating (NCIH) is a noninvasive treatment modality that can be used to cause thermal damage to bacterial biofilms on a metal implant surface in the context of a prosthetic joint infection. The purpose of this study was (1) to determine the effectiveness of NCIH on killing Staphylococcus aureus from biofilm and (2) to determine the possible synergistic effect of NCIH and cocktails of antibiotics and N-acetylcysteine (NAC).Methods:Staphylococcus aureus biofilms were grown on titanium alloy (Ti6Al4V) coupons. These coupons were heated to 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C for 3.5 min and subsequently exposed to cocktails of vancomycin, rifampicin and NAC at clinically relevant concentrations over 24 h.Results: In the control group without induction heating, 2.2*10[7] colony forming units (CFU)/cm[2] were observed. At 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C, a reduction of 0.3-log, 3.9-log, 4.2-log, 4.3-log, and 6.6-log CFU/cm[2] were observed, respectively. There was synergy between antibiotics and induction heating that resulted in less than 100 CFU/cm[2] remaining after 3.5 min at 60 °C, and exposure to vancomycin and rifampicin. Total eradication was observed at 80 °C. Total eradication was also observed at 60 °C and a cocktail of antibiotics with NAC.Conclusion: Induction heating of titanium alloy coupons is effective for the reduction of bacterial load in vitro in S. aureus biofilms. Induction heating and cocktails of antibiotics and NAC have a synergistic effect that results in the total eradication of the biofilm at 60 °C and higher for clinically relevant concentrations of vancomycin, rifampicin and NAC.}, } @article {pmid31986339, year = {2020}, author = {Martegani, E and Bolognese, F and Trivellin, N and Orlandi, VT}, title = {Effect of blue light at 410 and 455 nm on Pseudomonas aeruginosa biofilm.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {204}, number = {}, pages = {111790}, doi = {10.1016/j.jphotobiol.2020.111790}, pmid = {31986339}, issn = {1873-2682}, mesh = {Biofilms/*radiation effects ; Catalase/chemistry/genetics/metabolism ; DNA Damage/radiation effects ; Humans ; *Light ; Plasmids/metabolism/radiation effects ; Pseudomonas aeruginosa/isolation & purification/metabolism/*physiology ; Recombinant Proteins/biosynthesis/chemistry/isolation & purification ; Urinary Tract Infections/microbiology/pathology ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen resistant to many antibiotics, able to form biofilm and causes serious nosocomial infections. Among anti-Pseudomonas light-based approaches, the recent antimicrobial Blue Light (aBL) treatment seems very promising. The aim of this study was to evaluate the efficiency of blue light in inhibiting and/or eradicating P. aeruginosa biofilm. Light at 410 nm has been identified as successful in inhibiting biofilm formation not only of the model strain PAO1, but also of CAUTI (catheter-associated urinary tract infection) isolates characterized by their ability to form biofilm. Results of this work on 410 nm light also demonstrated that: i) at the lowest tested radiant exposure (75 J cm[-][2]) prevents matrix formation; ii) higher radiant exposures (225 and 450 J cm[-][2]) light impairs the cellular components of biofilm, adherent and planktonic ones; iii) light eradicates with a good rate young and older biofilms in a light dose dependent manner; iv) it is also efficient in inactivating catalase A, a virulence factor playing an important role in pathogenic mechanisms. Light at 455 nm, even if at a lower extent than 410 nm, showed a certain anti-Pseudomonas activity. Furthermore, light at 410 nm caused detrimental effects on enzyme activity of β-galactosidase and catalase A, and changes on plasmid DNA conformation and ortho-nitrophenyl-β-D-galactopyranoside structure. This study supports the potential of blue light for anti-infective and disinfection applications.}, } @article {pmid31986332, year = {2020}, author = {Zhang, P and Xu, C and Zhou, X and Qi, R and Liu, L and Lv, F and Li, Z and Wang, S}, title = {Cationic conjugated polymers for enhancing beneficial bacteria adhesion and biofilm formation in gut microbiota.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {188}, number = {}, pages = {110815}, doi = {10.1016/j.colsurfb.2020.110815}, pmid = {31986332}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Bifidobacterium longum subspecies infantis/drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Cations/chemistry/pharmacology ; Enterococcus faecalis/drug effects/growth & development ; Gastrointestinal Microbiome/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Particle Size ; Polymers/chemistry/*pharmacology ; Quaternary Ammonium Compounds/chemistry/*pharmacology ; Surface Properties ; Thiophenes/chemistry/*pharmacology ; }, abstract = {It is important to develop efficient therapeutic methods to maintain a healthy balance among gut microbiota by increasing the beneficial bacteria and decreasing the harmful bacteria. In this work, a cationic polythiophene derivative poly(3-(3'-N,N,N-triethylamino-1'-propyloxy)-4-methyl-2,5-thiophene hydrochloride) (PMNT) with quaternary ammonium groups as side chains has been used for efficiently promoting the initial adhesion and biofilm formation of beneficial bacteria in gut microbiota. Upon addition of PMNT, three species of gut microbiota have an increased biofilm formation ability (216.5 % for Escherichia coli (E. coli), 130.7 % for Bifidobacterium infantis (B. infants) and 47.6 % for Enterococcus faecalis (E. faecalis)). As the initial adhesion of bacteria to a surface is an essential step during biofilm formation, PMNT can promote the attachment of bacteria by forming bacteria /PMNT aggregates which possess more cell-to-cell interactions. RNA sequencing results of bacteria within biofilm indicate that the utilization of carbohydrate and glycan is accelerated in the presence of PMNT, leading to enhanced quorum sensing and biofilm formation of E. coli. After forming biofilm, beneficial bacteria have an enhanced resistance to adverse environmental conditions which is significant for maintaining the balance of gut microbiota. Conjugated polymers exhibit a good potential application in modulating the balance of gut microbiota and development of new probiotics drugs.}, } @article {pmid31985269, year = {2020}, author = {Ravaioli, S and Campoccia, D and Speziale, P and Pietrocola, G and Zatorska, B and Maso, A and Presterl, E and Montanaro, L and Arciola, CR}, title = {Various biofilm matrices of the emerging pathogen Staphylococcus lugdunensis: exopolysaccharides, proteins, eDNA and their correlation with biofilm mass.}, journal = {Biofouling}, volume = {36}, number = {1}, pages = {86-100}, doi = {10.1080/08927014.2020.1716217}, pmid = {31985269}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/growth & development ; DNA, Bacterial/*genetics ; Drug Resistance, Bacterial/drug effects/genetics ; Extracellular Polymeric Substance Matrix/genetics/*metabolism ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Polysaccharides, Bacterial/genetics/*metabolism ; Staphylococcus lugdunensis/drug effects/*growth & development/metabolism/ultrastructure ; }, abstract = {Staphylococcus lugdunensis is an emerging high-virulent pathogen causative of hospital-acquired infections. Biofilm formation is a complex pathogenic process that leads to well-established bacterial communities. There is a paucity of data on the composition of the biofilm matrix among S. lugdunensis strains. Here, twenty-two S. lugdunensis clinical isolates, mainly from orthopaedic infections but also from other clinical sources, were sub-grouped by ribotyping and dendrogram analysis. Biofilms were analysed by fluorimetric methods based on FITC-Wheat Germ Agglutinin, SYPRO Ruby and TOTO-1 dyes to detect exopolysaccharides, proteins and extracellular DNA (eDNA), respectively. Biofilm morphology was investigated under confocal laser scanning microscopy (CLSM). Isolates displayed intriguing diversities in biofilm mass and matrix composition. The content of exopolysaccharides was found to be to be strongly associated with the biofilm mass (R[2] = 0.882), while the content of proteins turned out to be weakly (R[2] = 0.465) and that of eDNA very weakly associated (R[2] = 0.202) to the biofilm mass.}, } @article {pmid31984626, year = {2020}, author = {Huma, ZE and Javed, I and Zhang, Z and Bilal, H and Sun, Y and Hussain, SZ and Davis, TP and Otzen, DE and Landersdorfer, CB and Ding, F and Hussain, I and Ke, PC}, title = {Nanosilver Mitigates Biofilm Formation via FapC Amyloidosis Inhibition.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {16}, number = {21}, pages = {e1906674}, pmid = {31984626}, issn = {1613-6829}, support = {R35 GM119691/GM/NIGMS NIH HHS/United States ; }, mesh = {*Amyloid/drug effects ; Animals ; Anti-Bacterial Agents/pharmacology ; *Bacterial Proteins/genetics/metabolism ; *Biofilms/drug effects ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Protein Binding/drug effects ; *Pseudomonas aeruginosa/drug effects/genetics ; *Silver/chemistry/pharmacology ; }, abstract = {Multidrug resistance of bacteria is a major challenge due to the wide-spread use of antibiotics. While a range of strategies have been developed in recent years, suppression of bacterial activity and virulence via their network of extracellular amyloid has rarely been explored, especially with nanomaterials. Here, silver nanoparticles and nanoclusters (AgNPs and AgNCs) capped with cationic branched polyethylenimine polymer are synthesized, and their antimicrobial potentials are determined at concentrations safe to mammalian cells. Compared with the ultrasmall AgNCs, AgNPs entail stronger binding to suppress the fibrillization of FapC, a major protein constituent of the extracellular amyloid matrix of Pseudomonas aeruginosa. Both types of nanoparticles exhibit concentration-dependent antibiofilm and antimicrobial properties against P. aeruginosa. At concentrations of 1 × 10[-6] m or below, both the bactericidal activity of AgNCs and the antibiofilm capacity of AgNPs are associated with their structure-mediated bio-nano interactions but not ion release. For AgNPs, specifically, their antibiofilm potency correlates with their capacity of FapC fibrillization inhibition, but not with their bactericidal activity. This study demonstrates the antimicrobial potential of safe nanotechnology through the novel route of amyloidosis inhibition.}, } @article {pmid31982771, year = {2020}, author = {Gustavsson, DJI and Suarez, C and Wilén, BM and Hermansson, M and Persson, F}, title = {Long-term stability of partial nitritation-anammox for treatment of municipal wastewater in a moving bed biofilm reactor pilot system.}, journal = {The Science of the total environment}, volume = {714}, number = {}, pages = {136342}, doi = {10.1016/j.scitotenv.2019.136342}, pmid = {31982771}, issn = {1879-1026}, mesh = {Ammonium Compounds ; *Biofilms ; Bioreactors ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Wastewater ; }, abstract = {Nitrogen removal from the mainstream of municipal wastewater with partial nitritation-anammox (PNA) would be highly beneficial with regard to the uses of energy and organic carbon. However, the challenges of process instability, low nitrogen removal rates (NRR) and unwanted aerobic nitrite oxidation need to be solved to reach large-scale implementation. Here, we have operated pilot-scale moving bed biofilm reactors (MBBRs) for mainstream treatment, together with sidestream treatment of sludge liquor from anaerobic digestors, for over 900 days to investigate process stability, reactor performance and microbial community structure at realistic conditions. The MBBR biofilm contained stable and high relative abundances of anammox bacteria (10-32%) consisting of two major Brocadia sp. populations, and several populations of aerobic ammonia-oxidising bacteria (AOB) within Nitrosomonas sp. (0.2-3.1%), as assessed by 16S rDNA amplicon sequencing. In addition, nitrite-oxidising bacteria (NOB) consisting of Nitrospira sp. (0.4-0.8%) and Nitrotoga sp. (up to 0.4%) were present. Nitrogen was removed at a peak rate of 0.66 g N m[-][2] d[-][1] (0.13 kg N m[-][3] d[-][1]) with a nitrate production over ammonium consumption of 15% by the NOB, at operation with continuous aeration at 15 °C. However, during most periods with continuous aeration, the NRR was lower (≈ 0.45 g N m[-][2] d[-][1]), with larger relative nitrate production (≈40%), presumably due to problems to maintain stable residual ammonium concentrations during wet-weather mainstream flows. Changing reactor operation to intermittent aeration decreased the NRR but did not help in suppressing the NOB. The study shows that with MBBRs, stable mainstream PNA can be attained at realistic NRR, but with need for post-treatment of nitrate, since effective NOB suppression was hard to achieve.}, } @article {pmid31982769, year = {2020}, author = {Tang, Z and Lin, Z and Wang, Y and Zhao, P and Kuang, F and Zhou, J}, title = {Coupling of thermophilic biofilm-based systems and ozonation for enhanced organics removal from high-temperature pulping wastewater: Performance, microbial communities, and pollutant transformations.}, journal = {The Science of the total environment}, volume = {714}, number = {}, pages = {136802}, doi = {10.1016/j.scitotenv.2020.136802}, pmid = {31982769}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors ; *Environmental Pollutants ; *Microbiota ; Ozone ; Temperature ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {This study focused on the establishment of thermophilic biofilm-based systems (TBSs) coupled with ozonation for treatment of high-temperature pulping wastewater. The effects of the inoculum, sludge growth mode, and temperature were investigated. These factors played roles in the organics removal performance and microbial communities of pulping wastewater treatment systems. At 50 °C, the TBS inoculated with optimal inoculum achieved 59.12% and 37.96% reductions in COD and chromaticity, which were superior to the reductions achieved by other systems. In this TBS, thermophilic lignocellulolytic microorganisms (Chloroflexus, Meiothermus, norank_f_Caldilineaceae, and Roseiflexus) and carbohydrate-fermenting bacteria (norank_f_Anaerolineaceae) were predominant. Their relative abundances were 25.55% and 10.42%, respectively. For enhanced removal of COD and chromaticity, an integrated system consisting of a primary TBS, ozonation, and a secondary TBS was proposed. The total COD and chromaticity removal efficiencies increased to 90.48% and 87.89%, respectively. BOD5/COD increased from 0.20 to 0.40, and shifts of lignin-like and humic acid-like substances were observed during ozonation with the primary TBS effluent.}, } @article {pmid31981870, year = {2020}, author = {P, D and H G, G and P, H}, title = {Co-occurrence of functionally diverse bacterial community as biofilm on the root surface of Eichhornia crassipes (Mart.) Solms-Laub.}, journal = {The Science of the total environment}, volume = {714}, number = {}, pages = {136683}, doi = {10.1016/j.scitotenv.2020.136683}, pmid = {31981870}, issn = {1879-1026}, mesh = {Bacteria ; *Biofilms ; *Eichhornia ; India ; Metals, Heavy ; }, abstract = {The current study investigates the functional diversity of bacterial community existing as a biofilm on the root surface of water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.) grown in Yamuna river, Delhi, India. Forty-nine bacterial isolates recorded a diverse pattern of susceptibility/resistance to 23 antibiotics tested. Most of the bacterial isolates were susceptible to Ofloxacin, Ciprofloxacin, Ceftriaxone, Gentamicin, and Cefepime and resistant to Ceftazidime, Nitrofurantoin, Ampicillin, and Nalidixic acid. Isolate RB33-V recorded resistant against 11 antibiotics tested, and RB42-V was found susceptible to most of the antibiotics tested. Among the seven heavy metals tested, the highest of 39 bacteria showed resistance to zinc, and least of 9 bacteria recorded resistance against cadmium. Isolate RB20-III was susceptible to all heavy metals tested, and RB23-III was found resistance for six heavy metals tested. A higher correlation was observed with zinc and multiple antibiotic resistance, and Ceftazidime resistance was most frequently associated with all the heavy metals tested. These bacteria grow optimally under neutral-alkali conditions and susceptible to acidic conditions, and they can withstand a broad range of temperatures and salt concentrations. They are very poor in phosphate solubilization. Further, the bacteria recorded varied results for beneficial traits, hemolytic, and DNase activity. The results of bacterial characterization indicated that this bacterial community is of multi-origin in nature and are assisting the host-plant in withstanding the adverse and fluctuating conditions of the Yamuna river by reducing the toxic effect of heavy metals, antibiotics and other xenobiotics.}, } @article {pmid31981410, year = {2020}, author = {Liu, L and Xiao, X and Li, K and Li, X and Shi, B and Liao, X}, title = {Synthesis of Catechin-Rare Earth Complex with Efficient and Broad-Spectrum Anti-Biofilm Activity.}, journal = {Chemistry & biodiversity}, volume = {17}, number = {3}, pages = {e1900734}, doi = {10.1002/cbdv.201900734}, pmid = {31981410}, issn = {1612-1880}, support = {2017YFB0308500//National Key R&D Program of China/ ; }, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Aspergillus niger/drug effects/metabolism ; Biofilms/*drug effects ; Catechin/chemistry/*pharmacology ; Coordination Complexes/chemical synthesis/chemistry/*pharmacology ; Metals, Rare Earth/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/metabolism ; Staphylococcus aureus/drug effects/metabolism ; Tea/chemistry ; }, abstract = {Biofilm is the crucial reason of clinical infections. Herein, green tea based polyphenol (catechin) and rare earth (RE) metal ions were employed for the preparation of catechin-RE complexes with significant anti-biofilm properties. The complexes were characterized by FT-IR, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS), which suggested that catechin coordinated with RE[3+] through its ortho phenolic hydroxy groups. The prepared catechin-RE showed significant effects in anti-biofilm growth against P. aeruginosa (Gram-negative bacteria), S. sciuri (Gram-positive bacteria), and A. niger (fungi), which significantly exceeded the utilization of catechin or RE[3+] . Morphological observations indicated that catechin supplied cell affinity to transfer RE[3+] and helped to damage cell membrane, which act as a carrier to exert cytotoxicity of RE[3+] to realize anti-biofilm. Differential gene expression analysis described gene expression changes induced by catechin-RE, including 56, 272 and 2160 downregulated genes for P. aeruginosa, S. sciuri and A. niger, respectively, which suggested critical changes in cellular metabolism, growth and other processes. These results illustrate the outstanding superiority of catechin-RE complexes in anti-infection aspect, i. e., the green tea based rare earth complexes are promising candidates for anti-biofilm applications to address serious challenges in the prevention of multiple infections.}, } @article {pmid31981035, year = {2020}, author = {Tziourrou, P and Vakros, J and Karapanagioti, HK}, title = {Using diffuse reflectance spectroscopy (DRS) technique for studying biofilm formation on LDPE and PET surfaces: laboratory and field experiments.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {11}, pages = {12055-12064}, pmid = {31981035}, issn = {1614-7499}, mesh = {Biofilms ; Ecosystem ; Plastics ; *Polyethylene ; *Polyethylene Terephthalates ; Spectrum Analysis ; }, abstract = {Biofilm formation on plastic debris needs to be further investigated, because microorganisms attached to plastics are transferred in all three dimensions to new regions by ocean currents. The current study aims to investigate biofilm formation on plastic strips in aquatic ecosystems using a simple physicochemical method commonly used to characterize solid surfaces, namely, the diffuse reflectance UV-Vis spectroscopy (DRS) method. Using virgin polymers that have not being exposed to the environment as a reference, DRS peaks can be attributed to the microorganisms attached to the polymer surface with time. The polymers tested were low-density polyethylene (LDPE) and polyethylene terephthalate (PET). For LDPE strips for all sampling times in the field, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength with time. For PET strips during the early sampling time, the development of the peaks among 10 similar samples was rather uniform in terms of peak wavelength but varied in terms of intensity. This last observation phased out with longer exposure times that the peaks had similar distribution in terms of peak wavelength and intensity. Similar experiments were run for longer exposure times both in an oligotrophic laboratory bioreactor and in the marine environment. In both cases, the biofilm on PET samples seems to reach a steady state faster than LDPE with similar peaks found on both samples DRS proved to be a robust and useful tool to study the formation of biofilm on plastic samples without any pretreatment and without sample destruction. Graphical abstract.}, } @article {pmid31980429, year = {2020}, author = {Salgar-Chaparro, SJ and Lepkova, K and Pojtanabuntoeng, T and Darwin, A and Machuca, LL}, title = {Nutrient Level Determines Biofilm Characteristics and Subsequent Impact on Microbial Corrosion and Biocide Effectiveness.}, journal = {Applied and environmental microbiology}, volume = {86}, number = {7}, pages = {}, pmid = {31980429}, issn = {1098-5336}, mesh = {Bacteria/*drug effects ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Corrosion ; Disinfectants/*therapeutic use ; Nutrients/analysis ; Steel/*chemistry ; }, abstract = {The impact that nutrient level has on biofilm characteristics, biocide effectiveness, and the associated risk of microbiologically influenced corrosion (MIC) was assessed using multispecies biofilms from two different oilfield consortia. A range of microbiological, microscopy, and corrosion methods demonstrated that the continuous flow of nutrients for the microbial growth resulted in higher activity, thickness, and robustness of the biofilms formed on carbon steel, which induced greater localized corrosion compared to biofilms formed under batch, nutrient-depleted conditions. Despite of the differences in biofilm characteristics, biofilms displayed comparable susceptibilities to glutaraldehyde biocide, with similar log10 reductions and percent reductions of microorganisms under both nutrient conditions. Nevertheless, nutrient replenishment impacted the effectiveness of the biocide in controlling microbial populations; a higher concentration of cells survived the biocide treatment in biofilms formed under a continuous flow of nutrients. Complementary DNA-/RNA-based amplicon sequencing and bioinformatics analysis were used to discriminate the active within the total populations in biofilms established at the different nutrient conditions and allowed the identification of the microbial species that remained active despite nutrient depletion and biocide treatment. Detection of persistent active microorganisms after exposure to glutaraldehyde, regardless of biofilm structure, suggested the presence of microorganisms less susceptible to this biocide and highlighted the importance of monitoring active microbial species for the early detection of biocide resistance in oil production facilities.IMPORTANCE Microbiologically influenced corrosion (MIC) is a complex process that generates economic losses to the industry every year. Corrosion must be managed to prevent a loss of containment of produced fluids to the external environment. MIC management includes the identification of assets with higher MIC risk, which could be influenced by nutrient levels in the system. Assessing biofilms under different nutrient conditions is essential for understanding the impact of flow regime on microbial communities and the subsequent impact on microbial corrosion and on the effectiveness of biocide treatment. This investigation simulates closely oil production systems, which contain piping sections exposed to continuous flow and sections that remain stagnant for long periods. Therefore, the results reported here are useful for MIC management and prevention. Moreover, the complementary methodological approach applied in this investigation highlighted the importance of implementing RNA-based methods for better identification of active microorganisms that survive stress conditions in oil systems.}, } @article {pmid31978734, year = {2020}, author = {Soliman, MYM and van Halem, D and Medema, G}, title = {Virus removal by ceramic pot filter disks: Effect of biofilm growth and surface cleaning.}, journal = {International journal of hygiene and environmental health}, volume = {224}, number = {}, pages = {113438}, doi = {10.1016/j.ijheh.2019.113438}, pmid = {31978734}, issn = {1618-131X}, mesh = {*Biofilms ; *Ceramics ; *Viruses ; Water Purification/*methods ; }, abstract = {Ceramic pot filters are household water treatment and safe storage (HWTS) systems designed to improve the microbial quality of drinking water. They yield high log reduction values (LRVs) for bacterial and protozoan pathogens but provide very little removal of viruses. This study investigated virus removal of ceramic filter discs (CFDs), using feed water with 3 different nutrient levels under extended continuous operation and limited cleaning frequency. The results show that filter use without cleaning resulted in biofilm growth and MS2 LRV values increased with increasing feed water nutrient content. Cleaning the filter surface by scrubbing led to a partial or total loss in improved LRVs, indicating the importance of this biological top layer to the removal of MS2. Overall, the removal capacity of a matured biofilm remained constant, regardless of its age. MS2 LRVs ranged between 0.9 ± 0.2 LRV for low nutrient (LN), 1.6 ± 0.2 LRV for medium nutrient (MN) and 2.4 ± 0.5 LRV for high nutrient (HN) biofilms. Interestingly, a change in feed conditions for the HN filters resulted in an unprecedented high LRV of >4 LRV, which supports further investigation of the mechanistic role of biofilms in virus removal.}, } @article {pmid31976811, year = {2020}, author = {Karballaei Mirzahosseini, H and Hadadi-Fishani, M and Morshedi, K and Khaledi, A}, title = {Meta-Analysis of Biofilm Formation, Antibiotic Resistance Pattern, and Biofilm-Related Genes in Pseudomonas aeruginosa Isolated from Clinical Samples.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {7}, pages = {815-824}, doi = {10.1089/mdr.2019.0274}, pmid = {31976811}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Drug Resistance, Bacterial/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Genes, Bacterial ; Humans ; Iran ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {Resistant microorganisms such as Pseudomonas aeruginosa grow by developing biofilms in hospitals. We aimed to investigate the biofilm formation and the frequencies of biofilm-related genes and their associations with antibiotic resistance pattern in P. aeruginosa isolated from Iranians' clinical samples. This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a systematic literature search in scientific databases using medical subject heading terms, including "Pseudomonas aeruginosa," "biofilm formation," "biofilm-related genes," "antibiotic resistance," and "prevalence," to obtain related articles published from 1st January, 2000, to 30th March, 2019. The studies reporting the prevalence of biofilm formation, the frequencies of biofilm-related genes, and the antibiotic resistance pattern in P. aeruginosa retrieved from Iranian patients were included. Meta-analysis was performed using the Comprehensive Meta-Analysis software. The pooled rate of biofilm formation was calculated as 86.5% (95% confidence interval [CI]: 79-91.6). The combined frequencies of strong, moderate, and weak biofilms were 51% (95% CI: 37.4-64.4), 29.2% (95% CI: 20.9-39.1), and 25.4% (95% CI: 11.5-47.2), respectively. The pooled prevalence of laslR, algD, algU, ppyR, and pelF genes were 93.6% (95% CI: 88.1-96.6), 91.4% (95% CI: 80.8-96.4), 89.3% (95% CI: 85.2-92.3), 98.7% (95% CI: 96.5-99.6), and 93% (95% CI: 82.7-97.3), respectively. The highest combined antibiotic resistance rates of P. aeruginosa isolates were against piperacillin/tazobactam (90%). This study showed that biofilm formation was higher in multidrug-resistant (MDR) P. aeruginosa than non-MDRs. A significant correlation was observed between biofilm formation and antibiotic resistance in 50% of studies included in this review.}, } @article {pmid31976318, year = {2019}, author = {Vargas-Cruz, N and Rosenblatt, J and Reitzel, RA and Chaftari, AM and Hachem, R and Raad, I}, title = {Pilot Ex Vivo and In Vitro Evaluation of a Novel Foley Catheter with Antimicrobial Periurethral Irrigation for Prevention of Extraluminal Biofilm Colonization Leading to Catheter-Associated Urinary Tract Infections (CAUTIs).}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {2869039}, pmid = {31976318}, issn = {2314-6141}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects ; Catheter-Related Infections/microbiology/*prevention & control ; Catheters, Indwelling ; Drug Resistance, Multiple, Bacterial/drug effects ; Enterococcus faecalis/drug effects ; Escherichia coli/drug effects ; Female ; Humans ; In Vitro Techniques ; Infection Control/methods ; Klebsiella pneumoniae/drug effects ; Models, Animal ; Proteus mirabilis/drug effects ; Pseudomonas aeruginosa/drug effects ; Swine ; Urinary Catheterization/instrumentation/*methods ; Urinary Tract Infections/microbiology/*prevention & control ; }, abstract = {CAUTI remains a serious healthcare issue for incontinent patients whose urine drainage is managed by catheters. A novel double-balloon Foley catheter was developed which was capable of irrigating the extraluminal catheter surfaces within the periurethral space between the urethral-bladder junction and meatus. The catheter has a retention cuff that is inflated to secure the catheter in the bladder and a novel irrigation cuff proximal to the urethral-bladder junction capable of providing periurethral irrigation from the urethral-bladder junction to the meatus. Uniform periurethral irrigation was demonstrated in an ex vivo porcine model by adding a dye to the antimicrobial urethral irrigation solution. An in vitro biofilm colonization model was adapted to study the ability of periurethral irrigation with a newly developed antimicrobial combination consisting of polygalacturonic acid + caprylic acid (PG + CAP) to prevent axial colonization of the extraluminal urethral indwelling catheter shaft by common uropathogens. The extraluminal surface of control catheters that were not irrigated formed biofilms along the entire axial urethral tract after 24 hours. Significant (p < 0.001) inhibition of colonization was seen against multidrug-resistant Pseudomonas aeruginosa (PA), carbapenem-resistant Escherichia coli (EC), and carbapenem-resistant Klebsiella pneumoniae (KB). For other common uropathogens including Candida albicans (CA), Proteus mirabilis (PR), and Enterococcus faecalis (EF), a first irrigation treatment completely inhibited colonization of half of the indwelling catheter closest to the bladder and a second treatment largely disinfected the remaining intraurethral portion of the catheter towards the meatus. The novel Foley catheter and PG + CAP antimicrobial irrigant prevented biofilm colonization in an in vitro CAUTI model and merits further testing in an in vivo CAUTI prevention model.}, } @article {pmid31975392, year = {2020}, author = {Shemesh, M and Ostrov, I}, title = {Role of Bacillus species in biofilm persistence and emerging antibiofilm strategies in the dairy industry.}, journal = {Journal of the science of food and agriculture}, volume = {100}, number = {6}, pages = {2327-2336}, doi = {10.1002/jsfa.10285}, pmid = {31975392}, issn = {1097-0010}, support = {4210306//Chief Scientist of the Ministry of Agriculture and Rural Development/ ; }, mesh = {Animals ; Bacillus/growth & development/*physiology ; *Biofilms ; Dairy Products/*microbiology ; Dairying/methods ; Food Microbiology ; Food-Processing Industry/methods ; }, abstract = {Biofilm-forming Bacillus species are often involved in persistent contamination and spoilage of dairy products. They therefore present a major microbiological challenge in the field of dairy food quality and safety. Due to their substantial physiological versatility, Bacillus species can survive in various parts of dairy manufacturing plants, leading to a high risk of product spoilage and potential dissemination of foodborne diseases. Furthermore, biofilm and heat-resistant spore formation make these bacteria challenging to eliminate. Thus, some strategies have been employed to remove, prevent, or delay the formation of Bacillus biofilms in the dairy industry, but with limited success. Lack of understanding of the Bacillus biofilm structure and behavior in conditions relevant to dairy-associated environments could partially account for this situation. The current paper reviews dairy-associated biofilm formation by Bacillus species, with particular attention to the role of biofilm in Bacillus species adaptation and survival in a dairy processing environment. Relevant model systems are discussed for the development of novel antimicrobial approaches to improve the quality of dairy food. © 2020 Society of Chemical Industry.}, } @article {pmid31974592, year = {2020}, author = {Tang, T and Chen, G and Guo, A and Xu, Y and Zhao, L and Wang, M and Lu, C and Jiang, Y and Zhang, C}, title = {Comparative proteomic and genomic analyses of Brucella abortus biofilm and planktonic cells.}, journal = {Molecular medicine reports}, volume = {21}, number = {2}, pages = {731-743}, pmid = {31974592}, issn = {1791-3004}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Brucella abortus/*genetics/isolation & purification/*metabolism/ultrastructure ; Gene Expression Regulation, Bacterial ; Plankton/*cytology ; *Proteomics ; RNA, Messenger/genetics/metabolism ; Reproducibility of Results ; Signal Transduction/genetics ; }, abstract = {The present study aimed to explore the differences in protein and gene expression of Brucella abortus cultured under biofilm and planktonic conditions. The proteins unique to biofilms and planktonic B. abortus were separated by two‑dimensional (2‑D) electrophoresis and then identified by matrix‑assisted laser desorption/ionization‑tandem time of flight‑mass spectrometry (MALDI‑TOF/TOF‑MS). High‑throughput sequencing and bioinformatic analyses were performed to identify differentially expressed genes between B. abortus cultured under biofilm and planktonic conditions. The proteins and genes identified by proteomic and genomic analyses were further evaluated via western blot and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analyses. 2‑D electrophoresis identified 20 differentially expressed protein spots between biofilms and planktonic cells, which corresponded to 18 individual proteins (12 downregulated and 6 upregulated) after MALDI‑TOF/TOF‑MS analysis, including elongation factor Tu and enolase. RT‑qPCR analysis revealed that all of the 18 genes were downregulated in biofilms compared with planktonic cells. Western blot analysis identified 9 downregulated and 3 upregulated proteins. High‑throughput sequencing and bioinformatic analyses identified 14 function and pathway‑associated genes (e.g., BAbS19_I14970). RT‑qPCR analysis of the 14 genes showed that they were upregulated in biofilm compared with in planktonic state. In conclusion, these differentially expressed genes may play important roles in bacterial defense, colonization, invasion, and virulence.}, } @article {pmid31973676, year = {2021}, author = {Dome, A and Chang, CY and Aunnop, W and Chayakorn, P}, title = {Microbial community composition in different carbon source types of biofilm A/O-MBR systems with complete sludge retention.}, journal = {Environmental technology}, volume = {42}, number = {19}, pages = {2950-2967}, doi = {10.1080/09593330.2020.1720301}, pmid = {31973676}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Microbiota ; Nitrogen ; Phosphorus ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {In this study, the three biofilm-anoxic-oxic-MBR systems were operated in parallel using different carbon source feed types. The three systems were operated with complete sludge retention to compare microbial community composition and system efficiency. High average removal of ammonia and COD was obtained in the three reactors. However, total nitrogen and total phosphorus removal efficiency were significantly higher in the VFAs feed systems when compared with the glucose feed system. The highest and most stable BNR efficiency was observed when acetate was used as a carbon source. The qPCR analysis revealed that ammonium oxidizing bacteria, denitrifiers and total bacteria were all highest in the acetate feed system followed by the propionate feed system. Moreover, among all carbon source types, the PUS-biofilm could maintain a higher degree of abundance of total bacteria than the sludge biomass. Meanwhile, ammonium oxidizing bacteria and denitrifiers were enriched in the sludge biomass rather than in the PUS-biofilm. The results of illumina sequencing revealed that acetate followed by propionate were favourable to the growth of microorganisms that were associated with the BNR process, which was the main reason for the high efficiency of nutrient removal in the acetate and propionate feed systems.}, } @article {pmid31973189, year = {2020}, author = {Liang, X and Zhang, XK and Peng, LH and Zhu, YT and Yoshida, A and Osatomi, K and Yang, JL}, title = {The Flagellar Gene Regulates Biofilm Formation and Mussel Larval Settlement and Metamorphosis.}, journal = {International journal of molecular sciences}, volume = {21}, number = {3}, pages = {}, pmid = {31973189}, issn = {1422-0067}, support = {41876159, 41476131, 41606147//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Bivalvia/microbiology/*physiology ; China ; Flagellin/*genetics/metabolism ; Host Microbial Interactions/genetics/*physiology ; Larva/microbiology/*physiology ; Marine Biology ; Metamorphosis, Biological/*physiology ; Mutation ; Mytilus/microbiology/physiology ; Pseudoalteromonas/cytology/*genetics/physiology ; Transcriptome ; }, abstract = {Biofilms are critical components of most marine systems and provide biochemical cues that can significantly impact overall community composition. Although progress has been made in the bacteria-animal interaction, the molecular basis of modulation of settlement and metamorphosis in most marine animals by bacteria is poorly understood. Here, Pseudoalteromonas marina showing inducing activity on mussel settlement and metamorphosis was chosen as a model to clarify the mechanism that regulates the bacteria-mussel interaction. We constructed a flagellin synthetic protein gene fliP deletion mutant of P. marina and checked whether deficiency of fliP gene will impact inducing activity, motility, and extracellular polymeric substances of biofilms. Furthermore, we examined the effect of flagellar proteins extracted from bacteria on larval settlement and metamorphosis. The deletion of the fliP gene caused the loss of the flagella structure and motility of the ∆fliP strain. Deficiency of the fliP gene promoted the biofilm formation and changed biofilm matrix by reducing β-polysaccharides and increasing extracellular proteins and finally reduced biofilm-inducing activities. Flagellar protein extract promoted mussel metamorphosis, and ∆fliP biofilms combined with additional flagellar proteins induced similar settlement and metamorphosis rate compared to that of the wild-type strain. These findings provide novel insight on the molecular interactions between bacteria and mussels.}, } @article {pmid31972305, year = {2020}, author = {Garcia, D and Mayfield, CK and Leong, J and Deckey, DG and Zega, A and Glasser, J and Daniels, AH and Eberson, C and Green, A and Born, C}, title = {Early adherence and biofilm formation of Cutibacterium acnes (formerly Propionibacterium acnes) on spinal implant materials.}, journal = {The spine journal : official journal of the North American Spine Society}, volume = {20}, number = {6}, pages = {981-987}, doi = {10.1016/j.spinee.2020.01.001}, pmid = {31972305}, issn = {1878-1632}, mesh = {Alloys ; Biofilms ; Humans ; *Propionibacterium acnes ; Prostheses and Implants ; *Spine ; Titanium ; }, abstract = {BACKGROUND: Cutibacterium acnes (C. acnes) is associated with infection following shoulder and spine surgery due to follicular pore concentrations in these anatomic regions. It has been established that it can form biofilms on surgical implant materials, which may contribute to its role in perioperative infection, but its behavior of early colonization on those materials is not yet well understood.

PURPOSE: The purpose of this study was to evaluate the time to adherence and subsequent biofilm formation of C. acnes in the first 24 hours on implant materials commonly used in spinal surgery.

STUDY DESIGN: We compared the colonization and behavior of C. acnes over time when applied to five commonly used spine implant materials - polyether ether ketone (PEEK), cobalt chromium (CC), stainless steel (SS), titanium, and titanium alloy.

METHODS: C. acnes was applied onto the samples of PEEK, CC, SS, titanium, and titanium alloy, and allowed to adhere for periods of 4, 8, 12, 16, and 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total 24 hours. Scanning electron microscopy and confocal laser scanning microscopy were used to visualize all samples for the presence and quantification of C. acnes adherence at each time period. Subsequent transition to biofilm formation on these samples was assessed via scanning electron microscopy at each time period.

RESULTS: The PEEK specimens exhibited the highest amount of surface biological burden in the first 24 hours compared with the other materials, which displayed little or no adherence. Rapid biofilm formation first observed at 8 hours of allowed adhesion on PEEK, whereas no significant biofilm formation was seen on the other materials during the observed time period.

CONCLUSIONS: Although C. acnes is known to have a slow proliferation rate, the results of this investigation demonstrate that it can rapidly adhere to and form a biofilm on PEEK. These data suggest that the use of PEEK implants placed during spinal surgery may facilitate early intraoperative colonization, and subsequent infection, compared with metallic implants.

CLINICAL SIGNIFICANCE: The findings of this study suggest that PEEK may prove to be problematic as a choice of implant material in cases were C. acnes infection is a possibility.}, } @article {pmid31972270, year = {2020}, author = {Vaezi, SS and Poorazizi, E and Tahmourespour, A and Aminsharei, F}, title = {Application of artificial neural networks to describe the combined effect of pH, time, NaCl and ethanol concentrations on the biofilm formation of Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {141}, number = {}, pages = {103986}, doi = {10.1016/j.micpath.2020.103986}, pmid = {31972270}, issn = {1096-1208}, mesh = {Algorithms ; Biofilms/*drug effects ; Ethanol/*pharmacology ; *Hydrogen-Ion Concentration ; *Neural Networks, Computer ; Sodium Chloride/*pharmacology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; }, abstract = {Biofilms are organized communities, adherent to the surface and resistant to adverse environmental and antimicrobial agents. So, its control is very important. Staphylococcus aureus is an opportunistic pathogen with the biofilm-forming ability that causes numerous problems in the medicine and food industry. Therefore, this study aimed to investigate the effect of pH, ethanol and NaCl concentrations after 24 and 48 h incubation times at 37 °C, also modeling the results with artificial neural network (ANN). For this purpose, after both incubation times, the effect of each parameter was studied, separately and also in combination at the levels in which the highest biofilm was formed. All results were modeled using multiple ANN and compared in terms of R-value and MSE. The highest biofilm formation ability was in neutral pH. Adding the ethanol and NaCl stimulated biofilm formation, but the inhibitory effect was observed at high concentrations of ethanol and NaCl and very acidic or highly alkaline pH levels. The more incubation time also led to an increase in biofilm formation. Eventually, the Feed-Forward, Back-Propagation Neural Network model with the Levenberg-Marquardt training algorithm and 4-12-1 topology was chosen (R-value = 0.995 and validation MSE = 0.011467). This ANN had high modeling ability because there was a high correlation between experimental data and modeling data. Therefore, it was concluded that pH, ethanol, NaCl, and time are effective parameters in the biofilm formation and there is a nonlinear relationship between these factors that the ANN is capable of modeling them.}, } @article {pmid31972092, year = {2020}, author = {Furuichi, Y and Yoshimoto, S and Inaba, T and Nomura, N and Hori, K}, title = {Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating through Sticky, Long, and Peritrichate Nanofibers.}, journal = {Environmental science & technology}, volume = {54}, number = {4}, pages = {2520-2529}, doi = {10.1021/acs.est.9b06577}, pmid = {31972092}, issn = {1520-5851}, mesh = {*Acinetobacter ; Adhesins, Bacterial ; Bacterial Adhesion ; Biofilms ; *Nanofibers ; }, abstract = {In this study, we elucidated the formation process of an unconventional biofilm formed by a bacterium autoagglutinating through sticky, long, and peritrichate nanofibers. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. Acinetobacter sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or extracellular polymeric substances production, Tol 5 cells quickly form an unconventional biofilm. The process forming this unconventional biofilm started with cell-cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell-cell interaction was described by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster-cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.}, } @article {pmid31970819, year = {2020}, author = {Wu, J and Fan, Y and Wang, X and Jiang, X and Zou, J and Huang, R}, title = {Effects of the natural compound, oxyresveratrol, on the growth of Streptococcus mutans, and on biofilm formation, acid production, and virulence gene expression.}, journal = {European journal of oral sciences}, volume = {128}, number = {1}, pages = {18-26}, doi = {10.1111/eos.12667}, pmid = {31970819}, issn = {1600-0722}, support = {C2018101771//China national undergraduate innovation and entrepreneurship training program/International ; NSFC 31800114//National Natural Science Foundation of China/International ; }, mesh = {Biofilms ; *Dental Caries/prevention & control ; Glucosyltransferases/genetics ; Humans ; Plant Extracts ; Stilbenes ; *Streptococcus mutans/genetics ; Virulence ; }, abstract = {Streptococcus mutans is one of the major pathogens of dental caries. Oxyresveratrol, a natural compound found in plants, exerts inhibitory effects on many bacterial species but its effect on S. mutans is unknown. The objective of this study was to clarify the antibacterial effect of oxyresveratrol on S. mutans, including effects on basic viability, acidogenicity, acidurity, and extracellular polysaccharide synthesis. The expression of nine genes that encode virulence and protective factors in S. mutans was measured by qRT-PCR. Oxyresveratrol showed a dose-dependent inhibitory effect on survival of S. mutans. At 250 μg ml[-1] , oxyresveratrol reduced the S. mutans survival rate, inhibited synthesis of water-insoluble glucans, compromised biofilm formation, and significantly down-regulated the expression of glucosyltransferase-I (gtfB) and glucosyltransferase-SI (gtfC). However, the enzymatic activity of lactate dehydrogenase protein was increased and the expression of lactate dehydrogenase (ldh) and ATP synthase subunit beta (atpD) genes were also up-regulated. Besides, glucosyltransferase S (gtfD) up-regulation indicated that water-soluble glucan synthesis was promoted. The vicR, liaR, and comDE genes, which exert a self-protective function in response to external stress, were also up-regulated. In conclusion, oxyresveratrol inhibited the growth of S. mutans and also reduced biofilm formation, acid production, and synthesis of water-insoluble glucans by this organism. In addition, oxyresveratrol also activated a series of S. mutans self-protection mechanisms.}, } @article {pmid31970432, year = {2020}, author = {Khan, F and Pham, DTN and Kim, YM}, title = {Alternative strategies for the application of aminoglycoside antibiotics against the biofilm-forming human pathogenic bacteria.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {5}, pages = {1955-1976}, doi = {10.1007/s00253-020-10360-1}, pmid = {31970432}, issn = {1432-0614}, mesh = {Adjuvants, Pharmaceutic/chemistry/pharmacology/therapeutic use ; Aminoglycosides/chemistry/*pharmacology/therapeutic use ; Anti-Bacterial Agents/chemistry/*pharmacology/therapeutic use ; Bacteria/*drug effects/growth & development/pathogenicity ; Bacterial Infections/drug therapy ; Biofilms/*drug effects/growth & development ; Drug Carriers/chemistry/pharmacology/therapeutic use ; Drug Resistance, Bacterial ; Drug Therapy, Combination ; Humans ; Virulence Factors/metabolism ; }, abstract = {Aminoglycosides are one of the common classes of antibiotics that have been widely used for treating infections caused by pathogenic bacteria. The mechanism of bactericidal action by aminoglycosides is well-known, by which it terminates the cytoplasmic protein synthesis. However, the potentials of aminoglycosides become hindered when facing the evolution of bacterial resistance mechanisms. Among multiple resistance mechanisms displayed by bacteria against antibiotics, the formation of biofilm is the mechanism that provides a barrier for antibiotics to reach the cellular level. Bacteria present in the biofilm also get protection against the impact of host immune responses, harsh environmental conditions, and other antimicrobial treatments. Hence, with the multifaceted resistance developed by biofilm-forming pathogenic bacteria, antibiotics are therefore discontinued for further applications. However, the recent research developed several alternative strategies such as optimization of the active concentration, modification of the environmental conditions, modification of the chemical structure, combinatorial application with other active agents, and formulation with biocompatible carrier materials to revitalize and exploit the new potential of aminoglycosides. The present review article describes the above mentioned multiple approaches and possible mechanisms for the application of aminoglycosides to treat biofilm-associated infections.}, } @article {pmid31969984, year = {2020}, author = {Caro-Astorga, J and Frenzel, E and Perkins, JR and Álvarez-Mena, A and de Vicente, A and Ranea, JAG and Kuipers, OP and Romero, D}, title = {Biofilm formation displays intrinsic offensive and defensive features of Bacillus cereus.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {}, pages = {3}, pmid = {31969984}, issn = {2055-5008}, mesh = {Bacillus cereus/*physiology ; Bacterial Adhesion ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; Cell Line ; Energy Metabolism ; Fermentation ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; HeLa Cells ; Humans ; Proteomics ; Reactive Oxygen Species/metabolism ; Sequence Analysis, RNA ; Spores, Bacterial/metabolism ; }, abstract = {Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneficial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm and to differentiate into the offensive or defensive features. We report that floating and biofilm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, biofilm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxification machinery and production of secondary metabolites. This strategy contributes to defend biofilm cells from competitors. However, floating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.}, } @article {pmid31969480, year = {2020}, author = {Uppuluri, P}, title = {Candida auris Biofilm Colonization on Skin Niche Conditions.}, journal = {mSphere}, volume = {5}, number = {1}, pages = {}, pmid = {31969480}, issn = {2379-5042}, support = {R01 AI141794/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms ; *Candida ; *Candidiasis ; Disease Outbreaks ; Humans ; Intensive Care Units ; }, abstract = {Candida auris, an emerging multidrug-resistant yeast, has recently been associated with outbreaks of invasive infections in health care facilities worldwide. Its success as a nosocomial pathogen lies in its capability to sustain for prolonged periods in the intensive care unit (ICU), adeptly colonize skin, and spread among patients. Little is known of the mechanism behind the predilection of C. auris for skin or the extent of its resilience on it. Now, M. V. Horton, C. J. Johnson, J. F. Kernien, T. D. Patel, et al. (mSphere 5:e00910-19, 2020, https://doi.org/10.1128/mSphere.00910-19) demonstrate that in synthetic sweat medium designed to mimic axillary skin conditions, C. auris can grow into multilayers of cells called biofilms that can resist desiccation. C. auris' propensity to form biofilms was further elaborated using a novel ex vivo porcine skin model of skin colonization. These studies provide early evidence that C. auris biofilm cells persisting on skin could serve as source of continuing outbreaks in health care facilities. Interventions blocking C. auris biofilm growth on skin will help control the spread of this pathogen.}, } @article {pmid31968443, year = {2020}, author = {Kumar, A and Gahlyan, S and Thakur, R and Devi, S and Duhan, S}, title = {Synthesis of Mesoporous SBA-16 and SBA-16/ZnO2 Nano-Composite Thin Film for Anti-Biofilm Application.}, journal = {Journal of nanoscience and nanotechnology}, volume = {20}, number = {7}, pages = {4210-4215}, doi = {10.1166/jnn.2020.17539}, pmid = {31968443}, issn = {1533-4899}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; Escherichia coli ; Hydrogen Peroxide/pharmacology ; *Nanocomposites ; Scattering, Small Angle ; Silicon Dioxide ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus ; X-Ray Diffraction ; *Zinc Oxide/pharmacology ; }, abstract = {SBA-16 is a mesoporous nanostructure with high surface area and cubic symmetry which make them an ideal carrier to carry different nanoparticles. Zinc peroxide (ZnO2) is a novel nanoparticle that inhibits the growth of microorganisms due to its antiseptic property. Thin film of SBA-16 and SBA-16/ZnO2 was deposited on glass slide by spin coating method. Anti-biofilm property of the thin films was examined against E. coli and S. aureus bacteria. Structural property was found out by wide angle X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and High Resolution Transmission Electron Microscope (HRTEM). Fourier Transform Infrared Spectrophotometer (FTIR) was used to confirmation the presence of ZnO2 in Nano-composite and AFM utilized for surface topography of thin films. Fluorescent microscope image clearly revealed that SBA-16/ZnO2 nanocomposite thin film significantly inhibit the biofilm formation against both E. coli (gram negative bacteria) as well as S. aureus (gram positive bacteria) in comparision to SBA-16. The antimicrobial behavior of ZnO nanoparticle is due to formation of H2O2 as reactive oxygen species (ROS) to which the bacterial cells are permeable. H2O2 is a powerful oxidizing agents that oxidized the mycobacterial elements like DNA and proteins which results into the toxicity of the bacteria cell.}, } @article {pmid31968224, year = {2020}, author = {Baddal, B}, title = {Characterization of biofilm formation and induction of apoptotic DNA fragmentation by nontypeable Haemophilus influenzae on polarized human airway epithelial cells.}, journal = {Microbial pathogenesis}, volume = {141}, number = {}, pages = {103985}, doi = {10.1016/j.micpath.2020.103985}, pmid = {31968224}, issn = {1096-1208}, mesh = {Apoptosis ; *Biofilms ; Cell Line ; *DNA Fragmentation ; *DNA, Bacterial ; Epithelial Cells/metabolism/microbiology ; Haemophilus Infections/*microbiology/pathology ; Haemophilus influenzae/classification/*genetics/*growth & development/ultrastructure ; Humans ; Respiratory Mucosa/*microbiology/pathology ; }, abstract = {Nontypeable Haemophilus influenzae (NTHi) is a common airway commensal and opportunistic pathogen that persists within biofilm communities in vivo. Biofilm studies so far are mainly based on assays on plastic surfaces. The aim of this work was to investigate the capacity of clinical NTHi strains to form biofilm structures on polarized Calu-3 human airway epithelial cells and primary normal human bronchial epithelial cells and to characterize the biofilm architecture. Formation of adherent NTHi biofilms post colonization of host cells at multiple time-points was evaluated using confocal laser scanning microscopy and electron microscopy. NTHi biofilms were analyzed in terms of biofilm height and presence of extracellular matrix components, and their apoptotic effects on epithelial cells were measured by TUNEL assay. Strain Fi176 was observed to form robust biofilms on airway epithelia over time, while disrupting the integrity of Calu-3 monolayer by 72 h of co-culture. NTHi biofilms were observed to induce apoptotic DNA fragmentation in host cells at 24 h post infection. Biofilm formation on cell monolayers by Fi176ΔpilA strain was markedly reduced compared to WT strain. Biofilm inhibition and disruption assays by crystal violet staining indicated that DNA and proteins are part of NTHi biofilms in vitro. Our findings highlight critical stages of NTHi pathogenesis following host colonization and provide useful biofilm models for future antimicrobial drug discovery investigations.}, } @article {pmid31968006, year = {2020}, author = {Nott, MA and Driscoll, HE and Takeda, M and Vangala, M and Corsi, SR and Tighe, SW}, title = {Advanced biofilm analysis in streams receiving organic deicer runoff.}, journal = {PloS one}, volume = {15}, number = {1}, pages = {e0227567}, pmid = {31968006}, issn = {1932-6203}, support = {P20 GM103449/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*drug effects/growth & development ; *Ice ; Linear Models ; Metagenomics ; Organic Chemicals/*toxicity ; Rivers/*chemistry ; Sphaerotilus/drug effects/genetics/physiology ; Water Pollutants, Chemical/*toxicity ; }, abstract = {Prolific heterotrophic biofilm growth is a common occurrence in airport receiving streams containing deicers and anti-icers, which are composed of low-molecular weight organic compounds. This study investigated biofilm spatiotemporal patterns and responses to concurrent and antecedent (i.e., preceding biofilm sampling) environmental conditions at stream sites upstream and downstream from Milwaukee Mitchell International Airport in Milwaukee, Wisconsin, during two deicing seasons (2009-2010; 2010-2011). Biofilm abundance and community composition were investigated along spatial and temporal gradients using field surveys and microarray analyses, respectively. Given the recognized role of Sphaerotilus in organically enriched environments, additional analyses were pursued to specifically characterize its abundance: a consensus sthA sequence was determined via comparison of whole metagenome sequences with a previously identified sthA sequence, the primers developed for this gene were used to characterize relative Sphaerotilus abundance using quantitative real-time PCR, and a Sphaerotilus strain was isolated to validate the determined sthA sequence. Results indicated that biofilm abundance was stimulated by elevated antecedent chemical oxygen demand concentrations, a surrogate for deicer concentrations, with minimal biofilm volumes observed when antecedent chemical oxygen demand concentrations remained below 48 mg/L. Biofilms were composed of diverse communities (including sheathed bacterium Thiothrix) whose composition appeared to shift in relation to antecedent temperature and chemical oxygen demand. The relative abundance of sthA correlated most strongly with heterotrophic biofilm volume (positive) and dissolved oxygen (negative), indicating that Sphaerotilus was likely a consistent biofilm member and thrived under low oxygen conditions. Additional investigations identified the isolate as a new strain of Sphaerotilus montanus (strain KMKE) able to use deicer components as carbon sources and found that stream dissolved oxygen concentrations related inversely to biofilm volume as well as to antecedent temperature and chemical oxygen demand. The airport setting provides insight into potential consequences of widescale adoption of organic deicers for roadway deicing.}, } @article {pmid31965942, year = {2020}, author = {Al Moaleem, MM and Porwal, A and Al Ahmari, NM and Shariff, M}, title = {Oral Biofilm on Dental Materials Among Khat Chewers.}, journal = {Current pharmaceutical biotechnology}, volume = {21}, number = {10}, pages = {964-972}, doi = {10.2174/1389201021666200121142300}, pmid = {31965942}, issn = {1873-4316}, mesh = {Adolescent ; Adult ; Aged ; Biofilms/*drug effects/growth & development ; Case-Control Studies ; Catha/*chemistry ; Central Nervous System Stimulants/pharmacology ; Composite Resins ; Dental Amalgam ; *Dental Materials ; Dental Prosthesis/*microbiology ; Female ; Humans ; Male ; *Mastication ; Microbiota/drug effects ; Middle Aged ; Oral Health ; Saudi Arabia ; Streptococcus/*growth & development ; Young Adult ; }, abstract = {BACKGROUND: Nowadays khat chewing habit is increasing among population in southern part of Saudi Arabia, Jazan and till date there is no literature investigating the effect of khat on oral biofilm on dental materials.

OBJECTIVE: To evaluate and compare the bacterial biofilm on different types of dental restorative materials used in replacing missing tooth structures among khat chewers and non-khat chewers.

MATERIALS AND METHODS: Hundred and twenty biofilm samples were collected from different dental restorations, such as All-ceramic (AL), Metal Ceramic (MC), Metal crowns or bridges (M), Composite (C), Glass Ionomer (GI) and Amalgam (A) restorations in non-khat and khat chewers (K). DNA extraction was done and subjected to PCR. Bacterial species, such as Streptococcus, Neisseria, Bacillus, Granulicatella and Veillonella were identified and counted. PCR products were also sequenced to detect similarity. Association between bacterial type and dental materials among non-khat and khat chewers were tested with Chi-Square test (Fishers Exact test).

RESULTS: The frequency and percentage of Streptococcus species were marginally higher among khat chewers (42; 70%) compared with non-khat chewers (38; 63.3%) group. But the Veillonella species were higher among non-khat chewers (9: 15%), compared to the khat chewers group (7; 11.7%). No statistically significant difference was detected among species in both groups. In non-khat and khat chewer group, the maximum hits were related to Streptococcus spp. in glass ionomer, amalgam, and composite (restorative materials), followed by metal ceramic and metal (prosthetic materials). Veillonella spp. showed maximum hits in the metal group among non-khat chewers and in all-ceramic among khat chewers. Statically significant differences were recorded among composite and amalgam samples with p values 0.047 and 0.036 in khat chewer group.

CONCLUSION: Khat chewers showed statistically significant differences in oral biofilm in the composite and amalgam restorative materials, but there were no significant differences found among any materials and species between the groups.}, } @article {pmid31965132, year = {2020}, author = {Kurmoo, Y and Hook, AL and Harvey, D and Dubern, JF and Williams, P and Morgan, SP and Korposh, S and Alexander, MR}, title = {Real time monitoring of biofilm formation on coated medical devices for the reduction and interception of bacterial infections.}, journal = {Biomaterials science}, volume = {8}, number = {5}, pages = {1464-1477}, pmid = {31965132}, issn = {2047-4849}, support = {/WT_/Wellcome Trust/United Kingdom ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Acrylates/chemistry/*pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Biomass ; Microbial Sensitivity Tests ; Optical Fibers ; Polymers/chemistry/*pharmacology ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Surface Properties ; Time Factors ; }, abstract = {Real time monitoring of bacterial attachment to medical devices provides opportunities to detect early biofilm formation and instigate appropriate interventions before infection develops. This study utilises long period grating (LPG) optical fibre sensors, incorporated into the lumen of endotracheal tubes (ETTs), to monitor in real time, Pseudomonas aeruginosa surface colonisation and biofilm formation. The wavelength shift of LPG attenuation bands was monitored for 24 h and compared with biofilm biomass, quantified using confocal fluorescence microscopy imaging. Biofilm formation was compared on uncoated ETTs and optical fibres, and on a biofilm resistant acrylate polymer, after challenge in an artificial sputum or minimal growth medium (RPMI-1640). The LPG sensor was able to detect a biofilm biomass as low as 81 μg cm[-2], by comparison with the confocal image quantification. An empirical exponential function was found to link the optical attenuation wavelength shift with the inverse of the biofilm biomass, allowing quantification of biofouling from the spectral response. Quantification from the sensor allows infection interception and early device removal, to reduce, for example, the risk of ventilator associated pneumonia.}, } @article {pmid31964697, year = {2020}, author = {Hsu, CY and Cairns, L and Hobley, L and Abbott, J and O'Byrne, C and Stanley-Wall, NR}, title = {Genomic Differences between Listeria monocytogenes EGDe Isolates Reveal Crucial Roles for SigB and Wall Rhamnosylation in Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {202}, number = {7}, pages = {}, pmid = {31964697}, issn = {1098-5530}, support = {/WT_/Wellcome Trust/United Kingdom ; MR/K015869/1/MRC_/Medical Research Council/United Kingdom ; 097945/B/11/Z/WT_/Wellcome Trust/United Kingdom ; 093714/Z/10/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Bacterial Adhesion ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Cell Wall/*metabolism ; Flagella/metabolism ; *Genome, Bacterial ; *Genomics/methods ; Genotype ; Listeria monocytogenes/*physiology ; Polymorphism, Single Nucleotide ; Rhamnose/metabolism ; Sigma Factor/*metabolism ; Whole Genome Sequencing ; }, abstract = {Listeria monocytogenes is a Gram-positive firmicute that causes foodborne infections, in part due to its ability to use multiple strategies, including biofilm formation, to survive adverse growth conditions. As a potential way to screen for genes required for biofilm formation, we harnessed the ability of bacteria to accumulate mutations in the genome over time, diverging the properties of seemingly identical strains. By sequencing the genomes of four laboratory reference strains of the commonly used L. monocytogenes EGDe, we showed that each isolate contains single nucleotide polymorphisms (SNPs) compared with the reference genome. We discovered that two SNPs, contained in two independent genes within one of the isolates, impacted biofilm formation. Using bacterial genetics and phenotypic assays, we confirmed that rsbU and rmlA influence biofilm formation. RsbU is the upstream regulator of the alternative sigma factor SigB, and mutation of either rsbU or sigB increased biofilm formation. In contrast, deletion of rmlA, which encodes the first enzyme for TDP-l-rhamnose biosynthesis, resulted in a reduction in the amount of biofilm formed. Further analysis of biofilm formation in a strain that still produces TDP-l-rhamnose but which cannot decorate the wall teichoic acid with rhamnose (rmlT mutant) showed that it is the decorated wall teichoic acid that is required for adhesion of the cells to surfaces. Together, these data uncover novel routes by which biofilm formation by L. monocytogenes can be impacted.IMPORTANCE Biofilms are an important mode of growth in many settings. Here, we looked at small differences in the genomes of the bacterium Listeria monocytogenes isolate EGDe and used them to find out how biofilms form. This important fundamental information may help new treatments to be developed and also highlights the fact that isolates of the same identity often diverge.}, } @article {pmid31964196, year = {2020}, author = {Alumutairi, L and Yu, B and Filka, M and Nayfach, J and Kim, MH}, title = {Mild magnetic nanoparticle hyperthermia enhances the susceptibility of Staphylococcus aureus biofilm to antibiotics.}, journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group}, volume = {37}, number = {1}, pages = {66-75}, pmid = {31964196}, issn = {1464-5157}, support = {R01 NR015674/NR/NINR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*therapeutic use ; Humans ; Hyperthermia, Induced/*methods ; Magnetite Nanoparticles/*therapeutic use ; Staphylococcus aureus/*drug effects ; }, abstract = {Objective: A critical challenge in the treatment of biofilm infection is the capacity of biofilm-grown bacteria to develop resistance to traditional antimicrobial therapies. The objective of this study was to validate the therapeutic potential of magnetic nanoparticle/alternating magnetic field (MNP/AMF) hyperthermia in combination with conventional antibiotics against biofilm infection.Materials and methods: The impact of MNP/AMF hyperthermia on the viability of S. aureus biofilm in the absence and presence of antibiotics as well as on the bactericidal activity of macrophages were evaluated at varying conditions of MNPs concentration and AMF intensity using in vitro cell culture models.Results: The application of MNP/AMF alone at a CEM43 thermal dose below the threshold for skin tissue exhibited a modest efficacy in the eradication of Staphylococcus aureus (S. aureus) biofilm (<1-log reduction). The treatment of antibiotics (ciprofloxacin, vancomycin) alone at a bactericidal concentration for planktonic S. aureus had no significant effect on the eradication of biofilm phase of S. aureus. However, when the biofilm was pre-exposed to mild MNP/AMF hyperthermia, the treatment of antibiotics could exhibit bactericidal effects against S. aureus biofilm, which was associated with increased uptake of antibiotics to the bacterial cells. Importantly, the application of MNP/AMF could promote the bactericidal activity of macrophages against intracellular bacteria via MNP-dependent generation of reactive oxygen species (ROS).Conclusion: Our results validate that the application of mild MNP/AMF hyperthermia within a safe thermal dose threshold is synergistic with conventional antibiotics as well as aids host innate immune response of macrophages for the clearance of intracellular bacteria.}, } @article {pmid31961499, year = {2020}, author = {Chen, L and Zou, Y and Kronfl, AA and Wu, Y}, title = {Type VI secretion system of Pseudomonas aeruginosa is associated with biofilm formation but not environmental adaptation.}, journal = {MicrobiologyOpen}, volume = {9}, number = {3}, pages = {e991}, pmid = {31961499}, issn = {2045-8827}, mesh = {*Adaptation, Physiological ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; *Environment ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Hydrogen-Ion Concentration ; Mutation ; Pseudomonas aeruginosa/*physiology/ultrastructure ; *Type VI Secretion Systems ; Virulence Factors/genetics ; }, abstract = {Pseudomonas aeruginosa encodes three type VI secretion systems (T6SSs), namely H1-, H2-, and H3-T6SS. P. aeruginosa hemolysin-coregulated protein (Hcp) is the effector protein and the hallmark of T6SS. Although T6SS is ubiquitous and affects ecology and human health, its general mechanism and physiological role are still not fully understood. Therefore, in this study, we investigated the impact of the P. aeruginosa T6SS on biofilm formation and environmental adaptation. To this end, we collected P. aeruginosa clinical isolates, divided them into strong biofilm formation (SBF) and nonbiofilm formation (NBF) groups based on their biofilm-forming ability, and compared their associated clinical characteristics. The duration of hospitalization was longer in patients infected with SBF than those infected with NBF strains. The expression levels of T6SS-related genes (hcp1 and hcp3) and a quorum-sensing gene (lasR) were higher in the SBF group as compared to those in the NBF group. In addition, the expression level of lasR was negatively associated with that of hcp1, but was positively associated with those of hcp2 and hcp3. Moreover, we evaluated the expression of T6SS- and biofilm-associated genes in planktonic and biofilm cells of the P. aeruginosa strain PAO1, and constructed strain PAO1△clpV1 to study the adaptation characteristics of H1-T6SS. The expression levels of hcp1, hcp2, hcp3, lasR, and other biofilm-associated genes were significantly higher in PAO1 biofilm cells as compared to those of planktonic cells. However, except for swarming ability as a vital feature for biofilm formation, there were no significant differences in the biofilm-forming ability and expression of biofilm-associated genes, adherence ability, growth characteristics, resistance to acid and osmotic pressure, surface structure, and morphology between the PAO1△clpV1 and PAO1 wild-type strains. Collectively, our results suggest that T6SS might play a role in biofilm formation and that H1-T6SS does not contribute to environmental adaptation in P. aeruginosa.}, } @article {pmid31960983, year = {2020}, author = {Gopalakrishnan, V and Masanam, E and Ramkumar, VS and Baskaraligam, V and Selvaraj, G}, title = {Influence of N-acylhomoserine lactonase silver nanoparticles on the quorum sensing system of Helicobacter pylori: A potential strategy to combat biofilm formation.}, journal = {Journal of basic microbiology}, volume = {60}, number = {3}, pages = {207-215}, doi = {10.1002/jobm.201900537}, pmid = {31960983}, issn = {1521-4028}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antineoplastic Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Carboxylic Ester Hydrolases/chemistry/*pharmacology ; Cell Line, Tumor ; Cell Membrane/chemistry/drug effects ; Cell Survival/drug effects ; Helicobacter pylori/*drug effects/metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions/drug effects ; Metal Nanoparticles/chemistry ; Mice ; Quorum Sensing/*drug effects ; RAW 264.7 Cells ; Silver/chemistry/*pharmacology ; Urease/metabolism ; }, abstract = {The treatment of Helicobacter pylori usually fails due to their ability to form biofilms and resistance to antibiotics. This might potentially lead to gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. In the present study, we elucidate the potential role of N-acylhomoserine lactonase stabilized silver nanoparticles (AiiA-AgNPs) in treating biofilms produced by H. pylori. AiiA-AgNPs inhibited quorum sensing (QS) by degradation of QS molecules, thereby reducing biofilm formation, urease production, and altering cell surface hydrophobicity of H. pylori. AiiA-AgNPs showed no cytotoxic effects on RAW 264.7 macrophages at the effective concentration (1-5 µM) of antibiofilm activity. In addition, AiiA-AgNP in high concentration (80-100 µM) exhibited cytotoxicity against HCT-15 carcinoma cells, depicting its therapeutic role in treating cancer.}, } @article {pmid31958506, year = {2020}, author = {Gellert, M and Hardt, S and Köder, K and Renz, N and Perka, C and Trampuz, A}, title = {Biofilm-active antibiotic treatment improves the outcome of knee periprosthetic joint infection: Results from a 6-year prospective cohort study.}, journal = {International journal of antimicrobial agents}, volume = {55}, number = {4}, pages = {105904}, doi = {10.1016/j.ijantimicag.2020.105904}, pmid = {31958506}, issn = {1872-7913}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Arthroplasty, Replacement, Knee/*adverse effects ; Biofilms/*drug effects ; Debridement ; Female ; Humans ; Knee Prosthesis/*microbiology ; Male ; Middle Aged ; Pain/prevention & control ; Prospective Studies ; Prosthesis-Related Infections/*drug therapy/microbiology ; Treatment Outcome ; }, abstract = {Biofilm-active antibiotics are suggested to improve the outcome in periprosthetic joint infection (PJI). However, the type, dose and duration of antibiotic treatment is rarely specified and their impact on outcomes is unknown. In this prospective cohort study, the infection and functional outcome were compared in 131 patients with knee PJI treated with or without biofilm-active antibiotics. The infection and functional outcome were evaluated by the Kaplan-Meier survival method to estimate the probability of infection-free survival; comparison between subgroups was performed by log-rank test. The influence of variables on the survival probability was analysed using univariate and multivariate Cox proportional-hazards regression models. Functional outcome was evaluated by pain intensity and the Knee injury and Osteoarthritis Outcome Score (KOOS). Among the 131 patients, 55 (42%) were treated with biofilm-active antibiotics and 76 (58%) were treated with non-biofilm-active antibiotics. The median follow-up period was 3.7 years (range, 2.0-7.6 years), and the infection-free survival probability was 74% (95% CI 61-85%) after 1 year and 56% (95% CI 47-66%) after 2 years. Infection-free survival after 1 year was better for patients who received biofilm-active antibiotics compared with those who did not (83% vs. 70%; P = 0.040) and remained superior after 2 years (67% vs. 48%; P = 0.038). In addition, biofilm-active antibiotic treatment was associated with lower pain intensity (P = 0.006) and higher KOOS on all five subscales. In patients with knee PJI, biofilm-active antibiotic therapy was associated with better infection outcome, lower pain intensity and better joint function.}, } @article {pmid31956979, year = {2020}, author = {Simkins, JW and Stewart, PS and Codd, SL and Seymour, JD}, title = {Microbial growth rates and local external mass transfer coefficients in a porous bed biofilm system measured by [19] F magnetic resonance imaging of structure, oxygen concentration, and flow velocity.}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {5}, pages = {1458-1469}, doi = {10.1002/bit.27275}, pmid = {31956979}, issn = {1097-0290}, support = {R01 GM109452/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Biotechnology/*methods ; Escherichia coli/metabolism ; Fluorine/analysis/metabolism ; Magnetic Resonance Spectroscopy/*methods ; *Oxygen/analysis/metabolism ; Porosity ; Rheology ; }, abstract = {[19] F nuclear magnetic resonance (NMR) oximetry and [1] H NMR velocimetry were used to noninvasively map oxygen concentrations and hydrodynamics in space and time in a model packed bed biofilm system in the presence and absence of flow. The development of a local oxygen sink associated with a single gel bead inoculated with respiring Escherichia coli was analyzed with a phenomenological model to determine the specific growth rate of the bacteria in situ, returning a value (0.66 hr[-1]) that was close to that measured independently in planktonic culture (0.62 hr[-1]). The decay of oxygen concentration in and around the microbiologically active bead was delayed and slower in experiments conducted under continuous flow in comparison to no-flow experiments. Concentration boundary layer thicknesses were determined and Sherwood numbers calculated to quantify external mass transfer resistance. Boundary layers were thicker in no-flow experiments compared to experiments with flow. Whereas the oxygen concentration profile across a reactive biofilm particle was symmetric in no-flow experiments, it was asymmetric with respect to flow direction in flow experiments with Sherwood numbers on the leading edge (Sh = 7) being larger than the trailing edge (Sh = 3.5). The magnitude of the experimental Sh was comparable to values predicted by a variety of correlations. These spatially resolved measurements of oxygen distribution in a geometrically complex model reveal in innovative detail the local coupling between microbial growth, oxygen consumption, and external mass transfer.}, } @article {pmid31956705, year = {2020}, author = {Kassinger, SJ and van Hoek, ML}, title = {Biofilm architecture: An emerging synthetic biology target.}, journal = {Synthetic and systems biotechnology}, volume = {5}, number = {1}, pages = {1-10}, pmid = {31956705}, issn = {2405-805X}, abstract = {Synthetic biologists are exploiting biofilms as an effective mechanism for producing various outputs. Metabolic optimization has become commonplace as a method of maximizing system output. In addition to production pathways, the biofilm itself contributes to the efficacy of production. The purpose of this review is to highlight opportunities that might be leveraged to further enhance production in preexisting biofilm production systems. These opportunities may be used with previously established production systems as a method of improving system efficiency further. This may be accomplished through the reduction in the cost of establishing and maintaining biofilms, and maintenance of the enhancement of product yield per unit of time, per unit of area, or per unit of required input.}, } @article {pmid31956232, year = {2019}, author = {Minami, M and Takase, H and Nakamura, M and Makino, T}, title = {Methanol extract of Lonicera caerulea var. emphyllocalyx fruit has anti-motility and anti-biofilm activity against enteropathogenic Escherichia coli.}, journal = {Drug discoveries & therapeutics}, volume = {13}, number = {6}, pages = {335-342}, doi = {10.5582/ddt.2019.01087}, pmid = {31956232}, issn = {1881-784X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; Enteropathogenic Escherichia coli/drug effects/*physiology ; Escherichia coli Proteins/genetics ; Fimbriae Proteins/genetics ; Flagella/drug effects/physiology ; Flagellin/genetics ; Fruit/chemistry ; Gene Expression Regulation, Bacterial/drug effects ; Lonicera/*chemistry ; Methanol/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/pharmacology ; }, abstract = {Foodborne diseases have become a worldwide problem that threatens public health and welfare. Enteropathogenic Escherichia coli (EPEC) is one of major pathogens of moderate to severe diarrhea. The increased prevalence of EPEC strains that produce extended spectrum β-lactamase (ESBL) has deepened the problem. The fruit of Lonicera caerulea var. emphyllocalyx (LCE) has been used as a traditional food preservative and medicine in northern temperate zones such as Hokkaido Island, Japan. In this study, we investigated the antibacterial effect of LCE fruit extract (LCEE) against EPEC. The antibacterial activities of LCEE were examined by bacterial growth, time-kill curve, soft-agar motility, electron microscopy, and 96 well-microplate biofilm assays. We also investigated the bacterial mRNA expression of biofilm-associated genes (fliC, csgA, and fimA) by quantitative real-time PCR assays. LCEE was found to suppress the growth, time-kill curve, and spread of EPEC. It also reduced the biofilm formation in a dose-dependent manner. Morphological analysis using transmission and scanning electron microscopy revealed that LCEE diminished the function of flagella resulting in reduced motility and biofilm formation. The mRNA expression of all three biofilm associated genes was downregulated under LCEE treatment. Extracts of the fruit of LCE inhibit the motility and biofilm formation of EPEC as a result of the inhibition of flagella development and function. We propose LCEE as a therapeutic candidate for the effective therapy of EPEC-associated infectious diseases.}, } @article {pmid31955835, year = {2020}, author = {Badaró, MM and Bueno, FL and Arnez, RM and Oliveira, VC and Macedo, AP and de Souza, RF and Paranhos, HFO and Silva-Lovato, CH}, title = {The effects of three disinfection protocols on Candida spp., denture stomatitis, and biofilm: A parallel group randomized controlled trial.}, journal = {The Journal of prosthetic dentistry}, volume = {124}, number = {6}, pages = {690-698}, doi = {10.1016/j.prosdent.2019.09.024}, pmid = {31955835}, issn = {1097-6841}, mesh = {Biofilms ; *Candida ; Candida albicans ; Colony Count, Microbial ; Disinfection ; Humans ; Sodium Hypochlorite ; *Stomatitis, Denture/therapy ; }, abstract = {STATEMENT OF PROBLEM: Antifungals are used to treat Candida infections. However, because of increased antifungal resistance and the length of antifungal therapy, Candida spp. infections can be prevented using the prosthesis hygiene method. Therefore, establishing efficient, safe, and low-cost hygiene protocols for complete denture wearers is necessary.

PURPOSE: The purpose of this clinical trial was to compare 10% Ricinus communis (RC10%) and 0.5% chloramine-T (CT0.5%) with negative (water) and positive (0.25% sodium hypochlorite [SH0.25%]) controls to establish a protocol to treat denture stomatitis (DS), remove denture biofilm, reduce overall microbiota, and decrease Candida spp. on the palate and denture bases.

MATERIAL AND METHODS: This randomized, double blind, controlled clinical trial allocated 60 DS-positive participants in parallel groups: RC10%, CT0.5%, negative control, and SH0.25%. All participants brushed their palate and dentures and applied 1 of the solutions only to the denture. The following outcomes were assessed at baseline and after 7 and 37 days: Candida spp. counts, frequency of species by presumptive identification, DS severity, and photographic quantification of biofilm. The Kruskal-Wallis and Friedman tests with stepwise step-down post hoc test compared the anticandidal effect and the DS score (between groups and time). ANOVA and the Tukey post hoc test were used for biofilm removal comparison (α=.05).

RESULTS: Microbial counts were solution- and time-dependent for dentures, with C. albicans, C. tropicalis, and C. glabrata being the most prevalent species. RC10% presented similar results to baseline and control after 7 and 37 days. CT0.5% reduced the CFU/mL compared with the baseline. SH0.25% was the most effective. DS reduced in all groups, independent of the solution. SH0.25% reduced biofilm the most, followed by RC10%. CT0.5% was similar to the control.

CONCLUSIONS: SH0.25% demonstrated potential for Candida spp. control in denture wearers with DS. The other protocols showed intermediate activity and might be more suitable for longer immersion periods.}, } @article {pmid31955046, year = {2020}, author = {Ryu, EJ and An, SJ and Sim, J and Sim, J and Lee, J and Choi, BK}, title = {Use of d-galactose to regulate biofilm growth of oral streptococci.}, journal = {Archives of oral biology}, volume = {111}, number = {}, pages = {104666}, doi = {10.1016/j.archoralbio.2020.104666}, pmid = {31955046}, issn = {1879-1506}, mesh = {Animals ; Biofilms ; Cattle ; Galactose ; *Streptococcus ; }, abstract = {In the oral microbial community, commensals can compete with pathogens and reduce their colonization in the oral cavity. A substance that can inhibit harmful bacteria and enrich beneficial bacteria is required to maintain oral health. The purpose of this study was to examine the effect of d-galactose on the biofilm formation of the cariogenic bacteria Streptococcus mutans and oral commensal streptococci and to evaluate their use in solution and in paste form. Biofilms of S. mutans, Streptococcus oralis, and Streptococcus mitis were formed on saliva-coated glass slips in the absence or presence of d-galactose and evaluated by staining with 1 % crystal violet. d-Galactose significantly inhibited the biofilm formation of S. mutans at concentrations ranging from 2 μM to 200 mM but increased the biofilm formation of S. oralis and S. mitis at concentrations of 2-200 mM. d-Galactose significantly inhibited three glucosyltransferase genes, gtfB, gtfC, and gtfD. The effect of d-galactose in the form of solution and paste was evaluated using bovine teeth. Pretreatment with 100 mM d-galactose on bovine teeth resulted in significantly reduced S. mutans biofilm formation. Our results suggest that d-galactose can be a candidate substance for the development of oral hygiene products to prevent caries by inhibiting the biofilm formation of S. mutans and simultaneously increasing the biofilm formation of commensal oral streptococci.}, } @article {pmid31955016, year = {2020}, author = {Keleştemur, S and Çobandede, Z and Çulha, M}, title = {Biofilm formation of clinically important microorganisms on 2D and 3D poly (methyl methacrylate) substrates: A surface-enhanced Raman scattering study.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {188}, number = {}, pages = {110765}, doi = {10.1016/j.colsurfb.2019.110765}, pmid = {31955016}, issn = {1873-4367}, mesh = {Biofilms ; Candida albicans/*physiology ; Particle Size ; Polymethyl Methacrylate/*chemistry ; Pseudomonas aeruginosa/*physiology ; Spectrum Analysis, Raman ; Staphylococcus epidermidis/*physiology ; Surface Properties ; }, abstract = {Clinically relevant microorganisms threaten patient's health often through biofilm formation on polymeric medical devices and implants. Poly (methyl methacrylate) is a commonly used polymer in medical implants and dental devices. In this study, biofilm characteristics of model microorganisms, Pseudomonas aeruginosa, Staphylococcus epidermidis and Candida albicans, were investigated at molecular level on 2-dimensional (2D) and 3-dimensional (3D) PMMA substrates to understand the influence of surface structures on biofilm formation and also to demonstrate the discrimination of microorganisms according to their metabolic activities by utilizing surface-enhanced Raman scattering (SERS). It was found that the fibrous 3D structure enhanced the assembly of microorganisms and enriched the biofilm structure while smooth polymeric surface decreased the biofilm formation rate and variety of biofilm content. Among the studied microorganisms, Pseudomonas aeruginosa and Candida albicans had a higher tendency to form biofilm on both 2D and 3D PMMA substrates. Although Staphlylococcus epidermidis showed slow adaption on PMMA surfaces, the 3D porous surfaces increased its biofilm formation rate significantly compared to 2D surface.}, } @article {pmid31954270, year = {2020}, author = {Abriat, C and Enriquez, K and Virgilio, N and Cegelski, L and Fuller, GG and Daigle, F and Heuzey, MC}, title = {Mechanical and microstructural insights of Vibrio cholerae and Escherichia coli dual-species biofilm at the air-liquid interface.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {188}, number = {}, pages = {110786}, doi = {10.1016/j.colsurfb.2020.110786}, pmid = {31954270}, issn = {1873-4367}, mesh = {Air ; Biofilms/*growth & development ; Escherichia coli/growth & development/*metabolism ; Particle Size ; Stress, Mechanical ; Surface Properties ; Vibrio cholerae/growth & development/*metabolism ; }, abstract = {Biofilm is the dominant microbial form found in nature, in which bacterial species are embedded in a self-produced extracellular matrix (ECM). These complex microbial communities are responsible for several infections when they involve multispecies pathogenic bacteria. In previous studies, interfacial rheology proved to be a unique quantitative technique to follow in real-time the biofilm formation at the air-liquid interface. In this work, we studied a model system composed of two bacteria pathogenic capable of forming a pellicle biofilm, V. cholerae and E. coli. We used an integrated approach by combining a real-time quantitative analysis of the biofilm rheological properties, with the investigation of major matrix components and the pellicle microstructure. The results highlight the competition for the interface between the two species, driven by the biofilm formation growth rate. In the dual-species biofilm, the viscoelastic properties were dominated by V. cholera, which formed a mature biofilm 18 h faster than E. coli. The microstructure of the dual-species biofilm revealed a similar morphology to V. cholerae alone when both bacteria were initially added at the same amount. The analysis of some major ECM components showed that E. coli was not able to produce curli in the presence of V. cholerae, unless enough time was given for E. coli to colonize the air-liquid interface first. E. coli secreted phosphoethanolamine (pEtN) cellulose in the dual-species biofilm, but did not form a filamentous structure. Our pathogenic model system demonstrated the importance of the biofilm growth rate for multispecies biofilm composition at the air-liquid interface.}, } @article {pmid31954031, year = {2020}, author = {Ahmed, K and Ahmed, H and Ahmed, FA and Ali, AA and Akbar, J and Rana, J and Tariq, U and Abidi, SH}, title = {Analysis of anti-microbial and anti-biofilm activity of hand washes and sanitizers against S. aureus and P. aeruginosa.}, journal = {JPMA. The Journal of the Pakistan Medical Association}, volume = {70}, number = {1}, pages = {100-104}, doi = {10.5455/JPMA.2776}, pmid = {31954031}, issn = {0030-9982}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Hand Sanitizers/*pharmacology ; Humans ; Infection Control ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects ; }, abstract = {OBJECTIVE: To analyse the biofilm-forming potential of clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa, and to assess antimicrobial activity of commonly used sanitizers in hospital and laboratory settings.

METHODS: The study was conducted at Aga Khan University Karachi from August 2016 to January 2017. The biofilm-forming potential of Staphylococcus aureus and Pseudomonas aeruginosa clinical isolates were evaluated qualitatively using air-liquid interface tube method, and air-liquid interface cover slip assay. The antimicrobial activity of commonly-used hand-washes and sanitizers were assessed using agar well diffusion method, while the anti-biofilm activity of the hand-washes and sanitizers was qualitatively assessed using air-liquid interface covers lip as s ay.

RESULTS: Of the eight hand-washes and sanitizers, 2(25%) showed antimicrobial activity against both Staphylococcus aureus and Pseudomonas aeruginosa, while 2(25%) exhibited antimicrobial activity against either S. aureus or P. aeruginosa. Also, 4 (50%) of them showed no inhibitory activity against S. aureus and P. aeruginosa.

CONCLUSIONS: The findings shall have important consequences with regards to infection control in hospital and laboratory settings.}, } @article {pmid31951842, year = {2020}, author = {Sun, J and Yang, P and Huang, S and Li, N and Zhang, Y and Yuan, Y and Lu, X}, title = {Enhanced removal of veterinary antibiotic from wastewater by photoelectroactive biofilm of purple anoxygenic phototroph through photosynthetic electron uptake.}, journal = {The Science of the total environment}, volume = {713}, number = {}, pages = {136605}, doi = {10.1016/j.scitotenv.2020.136605}, pmid = {31951842}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents/*isolation & purification ; Biofilms ; Electrons ; Rhodopseudomonas ; Wastewater ; }, abstract = {Purple anoxygenic phototrophs have been recently attracted substantial attention for their growing potential in wastewater treatment and their diverse metabolic patterns can be regulated for process control and optimization. In this study, the photoheterotrophic metabolism of Rhodopseudomonas palustris (R. palustris) was modified by photosynthetic electron uptake using a poised electrode which was explored to enhance removal of veterinary antibiotic from aqueous medium. The results showed that R. palustris grown as biofilm on electrode surface had excellent photoelectroactive activity and the photosynthetic electron uptake from the photoelectroactive biofilm significantly enhanced antibiotic florfenicol (FLO) degradation. The specific degradation rate of FLO at the set electrode potential of 0 V was 2.59-fold higher than that without applied potential. Enhanced co-metabolic reductive dehalogenation by use of the photosynthetic electrons extracted from co-substrate was mainly responsible for FLO degradation which eliminated the antibacterial activity of FLO. The electrode potential controlled the processes of photosynthetic electron uptake and its resultant FLO degradation. The fastest degradation of FLO was achieved at 0 V because the electrode poised at this potential stroke a proper balance between the enhancing photosynthetic electron uptake by serving as electron acceptor and minimizing competition with FLO for the photosynthetic electron from co-substrate. The activity of photoelectroactive biofilm was not negatively affected by FLO at environmental relevant concentration, suggesting its great potential for removal of antibiotic contaminants in wastewater. R. palustris could serve as a reservoir for floR resistance gene but its abundance can be diminished by choosing appropriate electrode potential.}, } @article {pmid31948958, year = {2020}, author = {Stüken, A and Haverkamp, THA}, title = {Metagenomic Sequences of Three Drinking Water and Two Shower Hose Biofilm Samples Treated with or without Copper-Silver Ionization.}, journal = {Microbiology resource announcements}, volume = {9}, number = {3}, pages = {}, pmid = {31948958}, issn = {2576-098X}, abstract = {We announce five shotgun metagenomics data sets from two Norwegian premise plumbing systems. The samples were shotgun sequenced on two lanes of an Illumina HiSeq 3000 instrument (THRUplex chemistry, 151 bp, paired-end reads), providing an extensive resource for sequence analyses of tap water and biofilm microbial communities.}, } @article {pmid31948634, year = {2020}, author = {Speranza, B and Corbo, MR and Campaniello, D and Altieri, C and Sinigaglia, M and Bevilacqua, A}, title = {Biofilm formation by potentially probiotic Saccharomyces cerevisiae strains.}, journal = {Food microbiology}, volume = {87}, number = {}, pages = {103393}, doi = {10.1016/j.fm.2019.103393}, pmid = {31948634}, issn = {1095-9998}, mesh = {*Biofilms ; Culture Media/chemistry/metabolism ; Hydrogen-Ion Concentration ; Probiotics/chemistry ; Saccharomyces cerevisiae/growth & development/*physiology ; }, abstract = {Four wild strains of Saccharomyces cerevisiae and the collection strain S. cerevisiae var. boulardii ATCC MYA-796 were used as test organisms to study the effect of some environmental conditions on the formation of biofilm by potentially probiotic yeasts. In a first step, the formation of biofilm was studied in four different media (YPD-Yeast Peptone Glucose; diluted YPD; 2% BP, a medium containing only bacteriological peptone; 2% GLC, a medium containing only glucose). Then, the dilution of YPD was combined with pH and temperature through a mixture design to assess the weight of the interaction of the variables; the experiments were done on S. boulardii and on S. cerevisiae strain 4. The dilution of nutrients generally determined an increased biofilm formation, whereas the effect of pH relied upon the strain. For S. cerevisiae strain 4, the highest level of sessile cells was found at pH 4-5, while S. boulardii experienced an enhanced biofilm formation at pH 6.0. Concerning temperature, the highest biofilm formation was found at 25-30 °C for both strains. The importance of this work lies in its extension of our knowledge of the effect of different environmental conditions on biofilm formation by potentially probiotic S. cerevisiae strains, as a better understanding of this trait could be an important screening tool into the selection of new multifunctional yeasts.}, } @article {pmid31948618, year = {2020}, author = {Vazquez-Armenta, FJ and Hernandez-Oñate, MA and Martinez-Tellez, MA and Lopez-Zavala, AA and Gonzalez-Aguilar, GA and Gutierrez-Pacheco, MM and Ayala-Zavala, JF}, title = {Quercetin repressed the stress response factor (sigB) and virulence genes (prfA, actA, inlA, and inlC), lower the adhesion, and biofilm development of L. monocytogenes.}, journal = {Food microbiology}, volume = {87}, number = {}, pages = {103377}, doi = {10.1016/j.fm.2019.103377}, pmid = {31948618}, issn = {1095-9998}, mesh = {Bacterial Adhesion/*drug effects ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Listeria monocytogenes/*drug effects/genetics/physiology ; Quercetin/*pharmacology ; Stainless Steel/chemistry ; Virulence Factors/*genetics/metabolism ; }, abstract = {The present study explored the effect of quercetin on the expression of virulence genes actA, inlA, inlC, and their regulatory components, sigB and prfA, in L. monocytogenes. Furthermore, the physicochemical changes on the surface, membrane permeability, and biofilm formation of quercetin-treated bacteria were evaluated. An inhibitory dose-dependent effect of quercetin (0.1-0.8 mM) was observed on the cell attachment on stainless steel at 2 and 6 h at 37 °C. Quercetin at 0.8 mM prevented the biofilm formation on stainless steel surfaces after 6 h of incubation at 37 °C, while the untreated bacteria formed biofilms with a cell density of 5.1 Log CFU/cm[2]. The microscopic analysis evidenced that quercetin at 0.2 mM decreased the biovolume and covered area of the attached micro-colonies. Also, sigB, prfA, inlA, inlC, and actA genes were downregulated by 7-29 times lower compared to untreated bacteria. In addition, quercetin decreased the superficial cell charge, increased the membrane permeability, and its surface hydrophobicity. These results demonstrated that quercetin prevented biofilm formation, repressed the genes of stress and virulence of L. monocytogenes and also altered the physicochemical cell properties.}, } @article {pmid31945398, year = {2020}, author = {Chen, H and Zhang, B and Weir, MD and Homayounfar, N and Fay, GG and Martinho, F and Lei, L and Bai, Y and Hu, T and Xu, HHK}, title = {S. mutans gene-modification and antibacterial resin composite as dual strategy to suppress biofilm acid production and inhibit caries.}, journal = {Journal of dentistry}, volume = {93}, number = {}, pages = {103278}, doi = {10.1016/j.jdent.2020.103278}, pmid = {31945398}, issn = {1879-176X}, mesh = {*Anti-Bacterial Agents ; *Biofilms ; Composite Resins ; *Dental Caries ; Humans ; Methacrylates ; *Resins, Synthetic ; Streptococcus mutans/*genetics ; }, abstract = {OBJECTIVE: Composite restorations are increasingly popular, but recurrent caries is a main reason for composite restoration failures. The objectives of this study were to investigate a dual strategy of combining rnc gene-deletion for Streptococcus mutans (S. mutans) with antibacterial dimethylaminohexadecyl methacrylate (DMAHDM) composite, and determine the effects of rnc gene-deletion alone, DMAHDM composite alone, and rnc-deletion plus DMAHDM composite, on biofilm growth and lactic acid production.

METHODS: Parent S. mutans (UA159, ATCC 700610) and rnc-deleted S. mutans were used. DMAHDM was incorporated into a composite at mass fractions of 0%, 1.5%, and 3%. Gene expressions for biofilm formation and drug resistance were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). Biofilms were grown on composite surfaces for 2 days. Live/dead, biomass, polysaccharide, metabolic activity (MTT), colony-forming units (CFU) and lactic acid production of biofilms were evaluated.

RESULTS: Compared to the parent S. mutans, the rnc-deletion technique yielded significantly less biofilm biomass, polysaccharides, metabolic activity, CFU, and lactic acid for biofilms grown on control composite (p <  0.05). With no gene modification, the biofilm CFU was decreased by 5-6 logs at 3% DMAHDM, when compared to control composite group. The dual strategy of combining rnc-deletion with 3% DMAHDM composite achieved the strongest biofilm-inhibition, with the greatest reduction in CFU by 8 logs. The combination of rnc-deletion with 3% DMAHDM composite decreased the biofilm lactic acid production by 95% (p <  0.05).

CONCLUSIONS: The dual strategy of rnc-deletion plus DMAHDM composite produced synergistic effects and achieved the strongest biofilm-inhibition. This method has great potential to inhibit dental caries and is promising to reduce secondary caries and protect tooth structures.}, } @article {pmid31944650, year = {2020}, author = {Lara, HH and Ixtepan-Turrent, L and Jose Yacaman, M and Lopez-Ribot, J}, title = {Inhibition of Candida auris Biofilm Formation on Medical and Environmental Surfaces by Silver Nanoparticles.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {19}, pages = {21183-21191}, pmid = {31944650}, issn = {1944-8252}, support = {R01 AI119554/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; }, mesh = {Antifungal Agents/*pharmacology ; Bandages/microbiology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Disinfectants/chemistry/*pharmacology ; Elastomers/chemistry ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Silicones/chemistry ; Silver/chemistry/*pharmacology ; Textiles/microbiology ; }, abstract = {Candida auris is an emerging pathogenic fungus implicated in healthcare-associated outbreaks and causes bloodstream infections associated with high mortality rates. Biofilm formation represents one of the major pathogenetic traits associated with this microorganism. Unlike most other Candida species, C. auris has the ability to survive for weeks on different surfaces. Therefore, there is an urgent need to develop new effective control strategies to combat the threat of C. auris. Advances in nanotechnologies have emerged that carry significant potential impact against Candida biofilms. We obtained pure round silver nanoparticles (AgNPs) (1 to 3 nm in diameter) using a microwave-assisted synthetic approach. When tested against C. auris, our results indicated a potent inhibitory activity both on biofilm formation (half maximal inhibitory concentration (IC50) of 0.06 ppm) and against preformed biofilms (IC50 of 0.48 ppm). Scanning electron microscopy images of AgNP-treated biofilms showed cell wall damage mostly by disruption and distortion of the outer surface of the fungal cell wall. In subsequent experiments AgNPs were used to functionalize medical and environmental surfaces. Silicone elastomers functionalized with AgNPs demonstrated biofilm inhibition (>50%) at relatively low concentrations (2.3 to 0.28 ppm). Bandage dressings loaded with AgNPs inhibited growth of C. auris biofilms by more than 80% (2.3 to 0.017 ppm). Also, to demonstrate long-lasting protection, dressings loaded with AgNPs (0.036 ppm) were washed thoroughly with phosphate-buffered saline, maintaining protection against the C. auris growth from cycles 1 to 3 (>80% inhibition) and from cycles 4 to 6 (>50% inhibition). Our results demonstrate the dose-dependent activity of AgNPs against biofilms formed by C. auris on both medical (silicone elastomer) and environmental (bandage fibers) surfaces. The AgNPs-functionalized fibers retain the fungicidal effect even after repeated thorough washes. Overall these results point to the utility of silver nanoparticles to prevent and control infections caused by this emerging pathogenic fungus.}, } @article {pmid31943660, year = {2020}, author = {Guan, W and Wang, T and Huang, Q and Tian, E and Liu, B and Yang, Y and Zhao, T}, title = {A LuxR-type regulator, AcrR, regulates flagellar assembly and contributes to virulence, motility, biofilm formation, and growth ability of Acidovorax citrulli.}, journal = {Molecular plant pathology}, volume = {21}, number = {4}, pages = {489-501}, pmid = {31943660}, issn = {1364-3703}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Citrullus/microbiology ; Comamonadaceae/genetics/*metabolism/*pathogenicity ; Cucurbitaceae/microbiology ; Plant Diseases/*microbiology ; Virulence ; }, abstract = {LuxR-type regulators regulate many bacterial processes and play important roles in bacterial motility and virulence. Acidovorax citrulli is a seedborne bacterial pathogen responsible for bacterial fruit blotch, which causes great losses in melon and watermelon worldwide. We identified a LuxR-type, nonquorum sensing-related regulator, AcrR, in the group II strain Aac-5 of A. citrulli. We found that the acrR mutant lost twitching and swimming motilities, and flagellar formation. It also showed reduced virulence, but increased biofilm formation and growth ability. Transcriptomic analysis revealed that 394 genes were differentially expressed in the acrR mutant of A. citrulli, including 33 genes involved in flagellar assembly. Our results suggest that AcrR may act as a global regulator affecting multiple important biological functions of A. citrulli.}, } @article {pmid31943428, year = {2020}, author = {Vitális, E and Nagy, F and Tóth, Z and Forgács, L and Bozó, A and Kardos, G and Majoros, L and Kovács, R}, title = {Candida biofilm production is associated with higher mortality in patients with candidaemia.}, journal = {Mycoses}, volume = {63}, number = {4}, pages = {352-360}, doi = {10.1111/myc.13049}, pmid = {31943428}, issn = {1439-0507}, support = {//EFOP-3.6.3-VEKOP-16-2017-00009/ ; ÚNKP-19-3//New National Excellence Program of the Ministry of Human Capacities./ ; }, mesh = {Biofilms/*growth & development ; *Candida/isolation & purification/metabolism ; Candida albicans/isolation & purification/metabolism ; Candida glabrata/isolation & purification/metabolism ; Candida parapsilosis/isolation & purification/metabolism ; Candida tropicalis/isolation & purification/metabolism ; Candidemia/*blood ; Female ; Humans ; Male ; *Mortality ; Retrospective Studies ; }, abstract = {BACKGROUND: Candidaemia is a common life-threatening disease among hospitalised patients, but the effect of the Candida biofilm-forming ability on the clinical outcome remains controversial.

OBJECTIVE: The aim was to determine the impact of biofilms, specifically focusing on biofilm mass and metabolic activity, on the mortality in candidaemia.

PATIENTS/METHODS: The clinical data of patients (n = 127) treated at the University of Debrecen, Clinical Centre, between January 2013 and December 2018, were investigated retrospectively. Biofilm formation was assessed using the crystal violet and XTT assays, measuring the biofilm mass and metabolic activity, respectively. Isolates were classified as low, intermediate and high biofilm producers both regarding biofilm mass and metabolic activity. The susceptibility of one-day-old biofilms to fluconazole, amphotericin B, anidulafungin, caspofungin and micafungin was evaluated and compared to planktonic susceptibility.

RESULTS: Intermediate/high biofilm mass was associated with significantly higher mortality (61%). All Candida tropicalis, Candida parapsilosis and Candida glabrata isolates originating from fatal infections were intermediate/high biofilm producers, whereas this ratio was 85% for Candida albicans. Solid malignancy was associated with intermediate/high biofilm producers (P = .043). The mortality was significantly higher in infections caused by Candida strains producing biofilms with intermediate/high metabolic activity (62% vs. 33%, P = .010). The ratio of concomitant bacteraemia was higher for isolates forming biofilms with low metabolic activity (53% vs 28%, P = .015).

CONCLUSIONS: This study provides evidence that the Candida biofilms especially with intermediate/high metabolic activity are related to higher mortality in candidaemia.}, } @article {pmid31942714, year = {2020}, author = {Zinicovscaia, I and Safonov, A and Boldyrev, K and Gundorina, S and Yushin, N and Petuhov, O and Popova, N}, title = {Selective metal removal from chromium-containing synthetic effluents using Shewanella xiamenensis biofilm supported on zeolite.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {10}, pages = {10495-10505}, pmid = {31942714}, issn = {1614-7499}, support = {18-29-25023-мк//Российский Фонд Фундаментальных Исследований (РФФИ)/ ; }, mesh = {Biofilms ; Chromium ; Metals ; Oxidation-Reduction ; *Shewanella ; Water Pollutants, Chemical/*analysis ; *Zeolites ; }, abstract = {A scheme of selective removal of metal ions from chromium-containing synthetic solutions with the following chemical composition, Cr (VI)-Fe (III), Cr (VI)-Fe (III)-Ni (II), Cr (VI)-Fe (III)-Ni (II)-Zn (II), and Cr (VI)-Fe (III)-Ni (II)-Zn (II)-Cu (II)) by Shewanella xiamenensis biofilm immobilized on a zeolite support, was proposed. Three biological processes, biosorption, bioaccumulation, and longtime bioreduction, were applied for metal removal. The process of Zn (II), Ni (II), and Cu (II) showed to be pH dependent. The maximum removal of Ni (II) was achieved during a 1-hour biosorption process at pH 5.0-6.0, of Zn (II) at pH 5.0, and of Cu (II) at pH 3.0. Chromium (VI) and Fe (III) ions were more efficiently removed by bioaccumulation. Chromium (VI) removal in the studied systems varied from 16.4% to 34.8 and of iron from 55.8 to 94.6%. In a long-term bioreduction experiment, it was possible to achieve complete reduction of Cr (VI) to Cr (III) ions by Shewanella xiamenensis in 42 days and by Shewanella xiamenensis biofilm on zeolite in 35 days. Shewanella oneidensis can be effectively used to remove metal ions from chemically complex effluents.}, } @article {pmid31942654, year = {2020}, author = {Drotleff, B and Roth, SR and Henkel, K and Calderón, C and Schlotterbeck, J and Neukamm, MA and Lämmerhofer, M}, title = {Lipidomic profiling of non-mineralized dental plaque and biofilm by untargeted UHPLC-QTOF-MS/MS and SWATH acquisition.}, journal = {Analytical and bioanalytical chemistry}, volume = {412}, number = {10}, pages = {2303-2314}, pmid = {31942654}, issn = {1618-2650}, mesh = {Bacteria/classification/genetics/isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; Chromatography, High Pressure Liquid/*methods ; Dental Plaque/*chemistry/microbiology ; Humans ; Lipidomics/*methods ; Lipids/*chemistry ; Saliva/chemistry/microbiology ; Software ; Tandem Mass Spectrometry/*methods ; Triglycerides ; }, abstract = {Dental plaque is a structurally organized biofilm which consists of diverse microbial colonies and extracellular matrix. Its composition may change when pathogenic microorganisms become dominating. Therefore, dental biofilm or plaque has been frequently investigated in the context of oral health and disease. Furthermore, its potential as an alternative matrix for analytical purposes has also been recognized in other disciplines like archeology, food sciences, and forensics. Thus, a careful in-depth characterization of dental plaque is worthwhile. Most of the conducted studies focused on the screening of microbial populations in dental plaque. Their lipid membranes, on the other hand, may significantly impact substance (metabolite) exchange within microbial colonies as well as xenobiotics uptake and incorporation into teeth. Under this umbrella, a comprehensive lipidomic profiling for determination of lipid compositions of in vivo dental plaque samples and of in vitro cultivated biofilm as surrogate matrix to be used for analytical purposes has been performed in this work. An untargeted lipidomics workflow utilizing a ultra-high-performance liquid chromatography (UHPLC)-quadrupole-time-of-flight (QTOF) platform together with comprehensive SWATH (sequential window acquisition of all theoretical fragment ion mass spectra) acquisition and compatible software (MS-DIAL) that comprises a vast lipid library has been adopted to establish an extensive lipidomic fingerprint of dental plaque. The main lipid components in dental plaque were identified as triacylglycerols, followed by cholesterol, cholesteryl esters as well as diacylglycerols, and various phospholipid classes. In vivo plaque is a rare matrix which is usually available in very low amounts. When higher quantities for specific research assays are required, efficient ways to produce an appropriate surrogate matrix are mandatory. A potential surrogate matrix substituting dental plaque was prepared by cultivation of in vitro biofilm from saliva and similarities and differences in the lipidomics profile to in vivo plaque were mapped by statistical evaluation post-analysis. It was discovered that most lipid classes were highly elevated in the in vitro biofilm samples, in particular diacylglycerols, phosphatidylglycerols, and phosphatidylethanolamines (PEs). Furthermore, an overall shift from even-chain lipid species to odd-chain lipids was observed in the cultivated biofilms. On the other hand, even-chain phosphatidylcholines (PCs), lysoPCs, cholesteryl esters, and cholesterol-sulfate were shown to be specifically increased in plaque samples. Graphical abstract.}, } @article {pmid31941912, year = {2020}, author = {Cui, Y and Schmid, BV and Cao, H and Dai, X and Du, Z and Ryan Easterday, W and Fang, H and Guo, C and Huang, S and Liu, W and Qi, Z and Song, Y and Tian, H and Wang, M and Wu, Y and Xu, B and Yang, C and Yang, J and Yang, X and Zhang, Q and Jakobsen, KS and Zhang, Y and Stenseth, NC and Yang, R}, title = {Evolutionary selection of biofilm-mediated extended phenotypes in Yersinia pestis in response to a fluctuating environment.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {281}, pmid = {31941912}, issn = {2041-1723}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms ; Biological Evolution ; China ; Climate ; DNA-Directed RNA Polymerases/genetics ; Disease Reservoirs ; Ecosystem ; Flea Infestations ; Genetic Variation ; Genome, Bacterial ; Host-Parasite Interactions ; Host-Pathogen Interactions ; Marmota/parasitology ; Phenotype ; Phylogeny ; Plague/*microbiology ; Sciuridae/parasitology ; Selection, Genetic ; Siphonaptera/*microbiology/physiology ; Yersinia pestis/genetics/*physiology ; }, abstract = {Yersinia pestis is transmitted from fleas to rodents when the bacterium develops an extensive biofilm in the foregut of a flea, starving it into a feeding frenzy, or, alternatively, during a brief period directly after feeding on a bacteremic host. These two transmission modes are in a trade-off regulated by the amount of biofilm produced by the bacterium. Here by investigating 446 global isolated Y. pestis genomes, including 78 newly sequenced isolates sampled over 40 years from a plague focus in China, we provide evidence for strong selection pressures on the RNA polymerase ω-subunit encoding gene rpoZ. We demonstrate that rpoZ variants have an increased rate of biofilm production in vitro, and that they evolve in the ecosystem during colder and drier periods. Our results support the notion that the bacterium is constantly adapting-through extended phenotype changes in the fleas-in response to climate-driven changes in the niche.}, } @article {pmid31941811, year = {2020}, author = {Park, C and Jung, HS and Park, S and Jeon, CO and Park, W}, title = {Dominance of Gas-Eating, Biofilm-Forming Methylobacterium Species in the Evaporator Cores of Automobile Air-Conditioning Systems.}, journal = {mSphere}, volume = {5}, number = {1}, pages = {}, pmid = {31941811}, issn = {2379-5042}, mesh = {*Air Conditioning ; *Automobiles ; Biofilms/*growth & development ; China ; India ; Methylobacterium/*physiology ; *Microbiota ; Republic of Korea ; United Arab Emirates ; United States ; Volatile Organic Compounds/metabolism ; }, abstract = {Microbial communities in the evaporator core (EC) of automobile air-conditioning systems have a large impact on indoor air quality, such as malodor and allergenicity. DNA-based microbial population analysis of the ECs collected from South Korea, China, the United States, India, and the United Arab Emirates revealed the extraordinary dominance of Methylobacterium species in EC biofilms. Mixed-volatile organic compound (VOC) utilization and biofilm-forming capabilities were evaluated to explain the dominance of Methylobacterium species in the ECs. The superior growth of all Methylobacterium species could be possible under mixed-VOC conditions. Interestingly, two lifestyle groups of Methylobacterium species could be categorized as the aggregator group, which sticks together but forms a small amount of biofilm, and the biofilm-forming group, which forms a large amount of biofilm, and their genomes along with phenotypic assays were analyzed. Pili are some of the major contributors to the aggregator lifestyle, and succinoglycan exopolysaccharide production may be responsible for the biofilm formation. However, the coexistence of these two lifestyle Methylobacterium groups enhanced their biofilm formation compared to that with each single culture.IMPORTANCE Air-conditioning systems (ACS) are indispensable for human daily life; however, microbial community analysis in automobile ACS has yet to be comprehensively investigated. A bacterial community analysis of 24 heat exchanger fins from five countries (South Korea, China, the United States, India, and the United Arab Emirates [UAE]) revealed that Methylobacterium species are some of the dominant bacteria in automobile ACS. Furthermore, we suggested that the predominance of Methylobacterium species in automobile ACS is due to the utilization of mixed volatile organic compounds and their great ability for aggregation and biofilm formation.}, } @article {pmid31941105, year = {2020}, author = {Lee, MJ and Kim, MJ and Oh, SH and Kwon, JS}, title = {Novel Dental Poly (Methyl Methacrylate) Containing Phytoncide for Antifungal Effect and Inhibition of Oral Multispecies Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {2}, pages = {}, pmid = {31941105}, issn = {1996-1944}, support = {6-2019-0021//Yonsei University College of Dentistry/ ; }, abstract = {Despite the many advantages of poly (methyl methacrylate) (PMMA) as a dental polymer, its antifungal and antibacterial effects remain limited. Here, phytoncide was incorporated into PMMA to inhibit fungal and biofilm accumulation without impairing the basic and biological properties of PMMA. A variable amount of phytoncide (0 wt % to 5 wt %) was incorporated into PMMA, and the basic material properties of microhardness, flexural strength and gloss were evaluated. In addition, cell viability was confirmed by MTT assay. This MTT assay measures cell viability via metabolic activity, and the color intensity of the formazan correlates viable cells. The fungal adhesion and viability on the PMMA surfaces were evaluated using Candida albicans (a pathogenic yeast). Finally, the thickness of saliva-derived biofilm was estimated. The flexural strength of PMMA decreased with increasing phytoncide contents, whereas there were no significant differences in the microhardness and gloss (p > 0.05) and the cell viability (p > 0.05) between the control and the phytoncide-incorporated PMMA samples. The amounts of adherent Candida albicans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness were significantly lower in the phytoncide-incorporated PMMA compared to the control (p < 0.05). Hence, it was concluded that the incorporation of appropriate amounts of phytoncide in PMMA demonstrated antifungal effects while maintaining the properties, which could be a possible use in dentistry application such as denture base resin.}, } @article {pmid31941090, year = {2020}, author = {Qian, W and Wang, W and Zhang, J and Liu, M and Fu, Y and Li, X and Wang, T and Li, Y}, title = {Sanguinarine Inhibits Mono- and Dual-Species Biofilm Formation by Candida albicans and Staphylococcus aureus and Induces Mature Hypha Transition of C. albicans.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {13}, number = {1}, pages = {}, pmid = {31941090}, issn = {1424-8247}, support = {11975177, 31760016//Innovative Research Group Project of the National Natural Science Foundation of China/ ; 2019216514GXRC001CG002-GXYD1.6//Science and technology plan project of Xi'an science and technology bureau/ ; 201926//the Xi'an Weiyang District Science and technology project/ ; ppxk2018-10//Ningbo health branding subject fund/ ; IMRFT20180103//Henan key laboratory of industrial microbial resources and fermentation technology/ ; }, abstract = {Previous studies have reported that sanguinarine possesses inhibitory activities against several microorganisms, but its effects on mono- and dual-species biofilms of C. albicans and S. aureus have not been fully elucidated. In this study, we aimed to evaluate the efficacy of sanguinarine for mono- and dual-species biofilms and explore its ability to induce the hypha-to-yeast transition of C. albicans. The results showed that the minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC90) of sanguinarine against C. albicans and S. aureus mono-species biofilms was 4, and 2 μg/mL, respectively, while the MIC and MBIC90 of sanguinarine against dual-species biofilms was 8, and 4 μg/mL, respectively. The decrease in the levels of matrix component and tolerance to antibiotics of sanguinarine-treated mono- and dual-species biofilms was revealed by confocal laser scanning microscopy combined with fluorescent dyes, and the gatifloxacin diffusion assay, respectively. Meanwhile, sanguinarine at 128 and 256 μg/mL could efficiently eradicate the preformed 24-h biofilms by mono- and dual-species, respectively. Moreover, sanguinarine at 8 μg/mL could result in the transition of C. albicans from the mature hypha form to the unicellular yeast form. Hence, this study provides useful information for the development of new agents to combat mono- and dual-species biofilm-associated infections, caused by C. albicans and S. aureus.}, } @article {pmid31940921, year = {2020}, author = {Savijoki, K and Miettinen, I and Nyman, TA and Kortesoja, M and Hanski, L and Varmanen, P and Fallarero, A}, title = {Growth Mode and Physiological State of Cells Prior to Biofilm Formation Affect Immune Evasion and Persistence of Staphylococcus aureus.}, journal = {Microorganisms}, volume = {8}, number = {1}, pages = {}, pmid = {31940921}, issn = {2076-2607}, support = {1292646)//Academy of Finland/ ; xx//Jane ja Aatos Erkon Säätiö/ ; }, abstract = {The present study investigated Staphylococcus aureus ATCC25923 surfaceomes (cell surface proteins) during prolonged growth by subjecting planktonic and biofilm cultures (initiated from exponential or stationary cells) to label-free quantitative surfaceomics and phenotypic confirmations. The abundance of adhesion, autolytic, hemolytic, and lipolytic proteins decreased over time in both growth modes, while an opposite trend was detected for many tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) scavenging, Fe-S repair, and peptidolytic moonlighters. In planktonic cells, these changes were accompanied by decreasing and increasing adherence to hydrophobic surface and fibronectin, respectively. Specific RNA/DNA binding (cold-shock protein CspD and ribosomal proteins) and the immune evasion (SpA, ClfA, and IsaB) proteins were notably more abundant on fully mature biofilms initiated with stationary-phase cells (SDBF) compared to biofilms derived from exponential cells (EDBF) or equivalent planktonic cells. The fully matured SDBF cells demonstrated higher viability in THP-1 monocyte/macrophage cells compared to the EDBF cells. Peptidoglycan strengthening, specific urea-cycle, and detoxification enzymes were more abundant on planktonic than biofilm cells, indicating the activation of growth-mode specific pathways during prolonged cultivation. Thus, we show that S. aureus shapes its surfaceome in a growth mode-dependent manner to reach high levofloxacin tolerance (>200-times the minimum biofilm inhibitory concentration). This study also demonstrates that the phenotypic state of the cells prior to biofilm formation affects the immune-evasion and persistence-related traits of S. aureus.}, } @article {pmid31937649, year = {2020}, author = {DelMain, EA and Moormeier, DE and Endres, JL and Hodges, RE and Sadykov, MR and Horswill, AR and Bayles, KW}, title = {Stochastic Expression of Sae-Dependent Virulence Genes during Staphylococcus aureus Biofilm Development Is Dependent on SaeS.}, journal = {mBio}, volume = {11}, number = {1}, pages = {}, pmid = {31937649}, issn = {2150-7511}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 AI125589/AI/NIAID NIH HHS/United States ; }, mesh = {Alleles ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Protein Kinases/*genetics ; Staphylococcus aureus/*genetics ; Transcription Factors/genetics ; Virulence ; Virulence Factors/*genetics ; }, abstract = {The intricate process of biofilm formation in the human pathogen Staphylococcus aureus involves distinct stages during which a complex mixture of matrix molecules is produced and modified throughout the developmental cycle. Early in biofilm development, a subpopulation of cells detaches from its substrate in an event termed "exodus" that is mediated by SaePQRS-dependent stochastic expression of a secreted staphylococcal nuclease, which degrades extracellular DNA within the matrix, causing the release of cells and subsequently allowing for the formation of metabolically heterogenous microcolonies. Since the SaePQRS regulatory system is involved in the transcriptional control of multiple S. aureus virulence factors, the expression of several additional virulence genes was examined within a developing biofilm by introducing fluorescent gene reporter plasmids into wild-type S. aureus and isogenic regulatory mutants and growing these strains in a microfluidic system that supplies the bacteria with a constant flow of media while simultaneously imaging developing biofilms in 5-min intervals. This study demonstrated that multiple virulence genes, including nuc, were expressed stochastically within a specialized subpopulation of cells in nascent biofilms. We demonstrated that virulence genes regulated by SaePQRS were stochastically expressed in nearly all strains examined whereas Agr-regulated genes were expressed more homogenously within maturing microcolonies. The commonly used Newman strain contains a variant of SaeS (SaeS[P]) that confers constitutive kinase activity to the protein and caused this strain to lack the stochastic expression pattern observed in other strain backgrounds. Importantly, repair of the SaeS[P] allele resulting in reversion to the well-conserved SaeS [L] allele found in other strains restored stochastic expression in this strain.IMPORTANCEStaphylococcus aureus is an important human pathogen capable of colonizing diverse tissue types and inducing severe disease in both immunocompromised and otherwise healthy individuals. Biofilm infections caused by this bacterial species are of particular concern because of their persistence, even in the face of intensive therapeutic intervention. The results of the current study demonstrate the stochastic nature of Sae-mediated virulence gene expression in S. aureus and indicate that this regulatory system may function as a "bistable switch" in a manner similar to that seen with regulators controlling competence gene expression in Bacillus subtilis and persister cell formation in Escherichia coli The results of this study provide a new perspective on the complex mechanisms utilized by S. aureus during the establishment of infections.}, } @article {pmid31936809, year = {2020}, author = {Yuan, Z and Dai, Y and Ouyang, P and Rehman, T and Hussain, S and Zhang, T and Yin, Z and Fu, H and Lin, J and He, C and Lv, C and Liang, X and Shu, G and Song, X and Li, L and Zou, Y and Yin, L}, title = {Thymol Inhibits Biofilm Formation, Eliminates Pre-Existing Biofilms, and Enhances Clearance of Methicillin-Resistant Staphylococcus aureus (MRSA) in a Mouse Peritoneal Implant Infection Model.}, journal = {Microorganisms}, volume = {8}, number = {1}, pages = {}, pmid = {31936809}, issn = {2076-2607}, support = {31702284//National Natural Science Foundation of China/ ; 03571444//Double subject construction plan of Sichuan Agriculture University/ ; CARS-SVDIP//Sichuan Veterinary Medicine and Drug Innovation Group of China Agricultural Research System/ ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a common human pathogen that causes several difficult-to-treat infections, including biofilm-associated infections. The biofilm-forming ability of S. aureus plays a pivotal role in its resistance to most currently available antibiotics, including vancomycin, which is the first-choice drug for treating MRSA infections. In this study, the ability of thymol (a monoterpenoid phenol isolated from plants) to inhibit biofilm formation and to eliminate mature biofilms, was assessed. We found that thymol could inhibit biofilm formation and remove mature biofilms by inhibiting the production of polysaccharide intracellular adhesin (PIA) and the release of extracellular DNA (eDNA). However, cotreatment with thymol and vancomycin was more effective at eliminating MRSA biofilms, in a mouse infection model, than monotherapy with vancomycin. Comparative histopathological analyses revealed that thymol reduced the pathological changes and inflammatory responses in the wounds. Assessments of white blood cell counts and serum TNF-α and IL-6 levels showed reduced inflammation and an increased immune response following treatment with thymol and vancomycin. These results indicate that combinatorial treatment with thymol and vancomycin has the potential to serve as a more effective therapy for MRSA biofilm-associated infections than vancomycin monotherapy.}, } @article {pmid31936769, year = {2020}, author = {Cui, L and Wang, X and Huang, D and Zhao, Y and Feng, J and Lu, Q and Pu, Q and Wang, Y and Cheng, G and Wu, M and Dai, M}, title = {CRISPR-cas3 of Salmonella Upregulates Bacterial Biofilm Formation and Virulence to Host Cells by Targeting Quorum-Sensing Systems.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {31936769}, issn = {2076-0817}, support = {P20GM103442//Foundation for the National Institutes of Health/ ; 2662017JC034//Fundamental Research Funds for the Central Universities/ ; AI101973-01//Foundation for the National Institutes of Health/ ; AI109317-01A1//Foundation for the National Institutes of Health/ ; 2017020201010228//Applied Basic Research Programs of Wuhan/ ; CARS-35//Earmarked Fund for China Agriculture Research System/ ; 2017YFC1600100//National Basic Research Program of China (973 Program)/ ; P20GM113123//Foundation for the National Institutes of Health/ ; P20 GM103442/GM/NIGMS NIH HHS/United States ; AI097532-01A1//Foundation for the National Institutes of Health/ ; P20 GM113123/GM/NIGMS NIH HHS/United States ; }, abstract = {Salmonella is recognized as one of the most common microbial pathogens worldwide. The bacterium contains the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems, providing adaptive immunity against invading foreign nucleic acids. Previous studies suggested that certain bacteria employ the Cas proteins of CRISPR-Cas systems to target their own genes, which also alters the virulence during invasion of mammals. However, whether CRISPR-Cas systems in Salmonella have similar functions during bacterial invasion of host cells remains unknown. Here, we systematically analyzed the genes that are regulated by Cas3 in a type I-E CRISPR-Cas system and the virulence changes due to the deletion of cas3 in Salmonella enterica serovar Enteritidis. Compared to the cas3 gene wild-type (cas3 WT) Salmonella strain, cas3 deletion upregulated the lsrFGBE genes in lsr (luxS regulated) operon related to quorum sensing (QS) and downregulated biofilm-forming-related genes and Salmonella pathogenicity island 1 (SPI-1) genes related to the type three secretion system (T3SS). Consistently, the biofilm formation ability was downregulated in the cas3 deletion mutant (Δcas3). The bacterial invasive and intracellular capacity of Δcas3 to host cells was also reduced, thereby increasing the survival of infected host cells and live chickens. By the transcriptome-wide screen (RNA-Seq), we found that the cas3 gene impacts a series of genes related to QS, the flagellum, and SPI-1-T3SS system, thereby altering the virulence phenotypes. As QS SPI-1-T3SS and CRISPR-Cas systems are widely distributed in the bacteria kingdom, our findings extend our understanding of virulence regulation and pathogenicity in mammalian hosts for Salmonella and potentially other bacteria.}, } @article {pmid31935721, year = {2020}, author = {Wang, J and Peng, X and Yin, W and Peng, Y and Liu, H and He, L}, title = {Eradication of Microorganisms Embedding in Biofilm by a Dose-Dependent Urokinase-Based Catheter Lock Solution in Chronic Hemodialysis Patients.}, journal = {Blood purification}, volume = {49}, number = {5}, pages = {586-596}, doi = {10.1159/000505566}, pmid = {31935721}, issn = {1421-9735}, mesh = {Bacteria/classification/*growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Catheter-Related Infections/microbiology/prevention & control ; Central Venous Catheters/*microbiology ; *Disinfection ; Female ; Humans ; Male ; Middle Aged ; *Renal Dialysis ; Urokinase-Type Plasminogen Activator/*administration & dosage ; }, abstract = {INTRODUCTION: Catheter-related blood stream infection (CRBSI), the most common complication of central vein catheter (CVC), was closely associated with high morbidity and mortality in hemodialysis (HD) patients. Conjunction with systemic antibiotic, antibiotic lock (ABL) is an important therapeutic option to salvage the catheter. With extra antimicrobial and biofilm removing properties, urokinase plasminogen activator (uPA)-based ABL could have a potential role in the treatment of CRBSI.

OBJECTIVE: In this study, we aimed to explore effectiveness of uPA-based (ABL) on microorganisms embedded in biofilms in vitro and CVC salvage rate in HD patients with CRBSI.

METHODS: In vitro, we induced biofilms formation on the surface of HD catheter by mimicking the development of CRBSI. Applying uPA with or without antibiotics on the kinds of microorganism biofilms to explore its antimicrobial and biofilm removing properties. In vivo, 86 HD patients diagnosed as CRBSI were retrospectively enrolled to see effectiveness of uPA-based ABL on catheter salvage rate as compare to heparin-based ABL.

RESULTS: uPA was effect to Staphylococcus epidermidis biofilms compared to Staphylococcus aureus, Escherichia coli, and Candida albicans. Less biofilm residues made the regrowth of S. epidermidis also limited. The combination of uPA with antibiotic showed better antimicrobial and antibiofilm activity than uPA alone or heparin-based ABL in vitro and in vivo. Among HD patients, uPA-based ABL did not cause any obvious adverse affects, and it was more effective in treating coagulase-negative Staphylococci related CRBSI than other microorganisms.

CONCLUSIONS: The combination of uPA and a therapeutic plasma concentration of sensitive antibiotic can work together to effectively remove coagulase-negative S. epidermidis embedded in biofilms in vitro. uPA-based ABL is safe and effective therapeutic intervention for HD patients with CRBSI, especially compared to heparin-based ABL.}, } @article {pmid31934774, year = {2020}, author = {Barilli, E and Vismarra, A and Frascolla, V and Rega, M and Bacci, C}, title = {Escherichia coli Strains Isolated from Retail Meat Products: Evaluation of Biofilm Formation Ability, Antibiotic Resistance, and Phylogenetic Group Analysis.}, journal = {Journal of food protection}, volume = {83}, number = {2}, pages = {233-240}, doi = {10.4315/0362-028X.JFP-19-330}, pmid = {31934774}, issn = {1944-9097}, abstract = {ABSTRACT: Escherichia coli is a ubiquitous organism capable of forming a biofilm. This is an important virulence factor and is critical in certain diseases and in the development of antibiotic resistance, which is increased by biofilm synthesis. In the present study, the potential health risk associated with handling and consumption of foods of animal origin contaminated with E. coli-producing biofilm was evaluated. We analyzed the ability of 182 E. coli strains isolated from pork, poultry, and beef, purchased in three different supermarkets in the area of the "Italian Food Valley" (Parma, northern Italy), to form biofilms. Positive strains were also tested for the presence of 12 biofilm-associated genes. Moreover, the 182 E. coli were characterized for antibiotic resistance, presence of multidrug resistance, extended-spectrum β-lactamase strains, and phylogenetic diversity through PCR. Twenty-five percent of the isolates produced biofilm. The majority showed weak adherence, five were moderate, and three were strong producers. E. coli with a strong adherence capability (three of three) harbored eight biofilm-associated genes, while weak and moderate producers harbored only five (frequencies ranging from 80 to 100%). Multidrug resistance was observed in 20 biofilm-producing E. coli, and 15 of these belonged to phylogenetic group D. Among nonbiofilm producers, the percentage of strains belonging to phylogenetic groups B2 and D was approximately 40%, highlighting a potential health risk for consumers and people handling contaminated products. The present study underlines the importance of monitoring the prevalence and characteristics of E. coli contaminating retail meat in relation to the potential virulence highlighted here.}, } @article {pmid31934739, year = {2020}, author = {Li, J and Zhong, W and Zhang, K and Wang, D and Hu, J and Chan-Park, MB}, title = {Biguanide-Derived Polymeric Nanoparticles Kill MRSA Biofilm and Suppress Infection In Vivo.}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {19}, pages = {21231-21241}, doi = {10.1021/acsami.9b17747}, pmid = {31934739}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*therapeutic use ; Biguanides/chemistry/therapeutic use ; Biofilms/*drug effects ; Female ; Male ; Metformin/analogs & derivatives/therapeutic use ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Microbial Sensitivity Tests ; Nanoparticles/chemistry/*therapeutic use ; Poloxamer/chemistry/*therapeutic use ; Staphylococcal Infections/*drug therapy ; Tannins/chemistry/therapeutic use ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of drug-resistant infections. Its propensity to develop biofilms makes it especially resistant to conventional antibiotics. We present a novel nanoparticle (NP) system made from biocompatible F-127 surfactant, tannic acid (TA), and biguanide-based polymetformin (PMET) (termed FTP NPs), which can kill MRSA biofilm bacteria effectively in vitro and in vivo and which has excellent biocompatibility. FTP NPs exhibit biofilm bactericidal activity-ability to kill bacteria both inside and outside biofilm-significantly better than many antimicrobial peptides or polymers. At low concentrations (8-32 μg/mL) in vitro, FTP NPs outperformed PMET with ∼100-fold (∼2 log10) greater reduction of MRSA USA300 biofilm bacterial cell counts, which we attribute to the antifouling property of the hydrophilic poly(ethylene glycol) contributed by F-127. Further, in an in vivo murine excisional wound model, FTP NPs achieved 1.8 log10 reduction of biofilm-associated MRSA USA300 bacteria, which significantly outperformed vancomycin (0.8 log10 reduction). Moreover, in vitro cytotoxicity tests showed that FTP NPs have less toxicity than PMET toward mammalian cells, and in vivo intravenous injection of FTP NPs at 10 mg/kg showed no acute toxicity to mice with negligible body weight loss and no significant perturbation of blood biomarkers. These biguanide-based FTP NPs are a promising approach to therapy of MRSA infections.}, } @article {pmid31934344, year = {2020}, author = {Thöming, JG and Tomasch, J and Preusse, M and Koska, M and Grahl, N and Pohl, S and Willger, SD and Kaever, V and Müsken, M and Häussler, S}, title = {Parallel evolutionary paths to produce more than one Pseudomonas aeruginosa biofilm phenotype.}, journal = {NPJ biofilms and microbiomes}, volume = {6}, number = {}, pages = {2}, pmid = {31934344}, issn = {2055-5008}, mesh = {A549 Cells ; Bacterial Adhesion ; Biofilms/*growth & development ; Evolution, Molecular ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; Humans ; Phenotype ; Phylogeny ; Plankton/*microbiology ; Plant Proteins/*genetics ; Pseudomonas aeruginosa/*physiology ; Sequence Analysis, RNA ; Virulence ; }, abstract = {Studying parallel evolution of similar traits in independent within-species lineages provides an opportunity to address evolutionary predictability of molecular changes underlying adaptation. In this study, we monitored biofilm forming capabilities, motility, and virulence phenotypes of a plethora of phylogenetically diverse clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. We also recorded biofilm-specific and planktonic transcriptional responses. We found that P. aeruginosa isolates could be stratified based on the production of distinct organismal traits. Three major biofilm phenotypes, which shared motility and virulence phenotypes, were produced repeatedly in several isolates, indicating that the phenotypes evolved via parallel or convergent evolution. Of note, while we found a restricted general response to the biofilm environment, the individual groups of biofilm phenotypes reproduced biofilm transcriptional profiles that included the expression of well-known biofilm features, such as surface adhesive structures and extracellular matrix components. Our results provide insights into distinct ways to make a biofilm and indicate that genetic adaptations can modulate multiple pathways for biofilm development that are followed by several independent clinical isolates. Uncovering core regulatory pathways that drive biofilm-associated growth and tolerance towards environmental stressors promises to give clues to host and environmental interactions and could provide useful targets for new clinical interventions.}, } @article {pmid31933125, year = {2020}, author = {Le, TN and Lee, CK}, title = {Surface Functionalization of Poly(N-Vinylpyrrolidone) onto Poly(Dimethylsiloxane) for Anti-Biofilm Application.}, journal = {Applied biochemistry and biotechnology}, volume = {191}, number = {1}, pages = {29-44}, doi = {10.1007/s12010-020-03238-5}, pmid = {31933125}, issn = {1559-0291}, mesh = {Anti-Infective Agents/*chemistry ; Biofilms/*growth & development ; Dimethylpolysiloxanes/*chemistry ; Povidone/*analogs & derivatives/chemistry ; Staphylococcus epidermidis/*physiology ; Surface Properties ; }, abstract = {Poly(dimethylsiloxane) (PDMS) has been widely used in the field of microfluidics, optical systems, and sensors. However, the hydrophobic nature of PDMS leads to low surface wettability and biofouling problems due to the nonspecific proteins-hydrophobic surface interactions and cell/bacterial adhesion. In this work, the PDMS surface was first introduced with amino groups (PDMS-NH2) via KOH-catalyzed reaction with 3-aminopropyltriethoxysilane (APTES). The PDMS-NH2 was then grafted with poly(N-vinylpyrrolidone) (PVP) based on the self-adhesion reaction between the amino surface and catechol-functionalized PVP (CA-PLL-PVP). CA-PLL-PVP as a comb-polymer was synthesized by conjugating PVP-COOH along with caffeic acid to the ε-polylysine backbone. A significantly enhanced water wettability was observed with contact angles dropped from 116° to 14° after coating with CA-PLL-PVP. The coated surface demonstrated excellent antifouling performance that no appreciable Staphylococcus epidermidis biofilm formation could be observed. This novel facile antifouling coating on PDMS surface may find greater biomedical applications to eliminate the potential adherence problems caused by natural biofouling.}, } @article {pmid31932378, year = {2020}, author = {Jin, Y and Guo, Y and Zhan, Q and Shang, Y and Qu, D and Yu, F}, title = {Subinhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Upregulating cidA.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {3}, pages = {}, pmid = {31932378}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Mupirocin/*pharmacology ; Staphylococcus aureus/*drug effects/genetics ; }, abstract = {Previous studies have shown that the administration of antibiotics at subinhibitory concentrations stimulates biofilm formation by the majority of multidrug-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated the effect of subinhibitory concentrations of mupirocin on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and the highly mupirocin-resistant clinical S. aureus SA01 to SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, quantitative real-time PCR (RT-qPCR) results revealed that this effect was largely due to the involvement of holin-like and antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased by 6.05- to 35.52-fold (P < 0.01) after mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation than that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.}, } @article {pmid31932310, year = {2020}, author = {Kimbrough, JH and Cribbs, JT and McCarter, LL}, title = {Homologous c-di-GMP-Binding Scr Transcription Factors Orchestrate Biofilm Development in Vibrio parahaemolyticus.}, journal = {Journal of bacteriology}, volume = {202}, number = {6}, pages = {}, pmid = {31932310}, issn = {1098-5530}, support = {T32 AI007511/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/chemistry/metabolism ; Gene Expression Regulation, Bacterial ; Models, Molecular ; Molecular Conformation ; Mutation ; Operon ; Phenotype ; Protein Binding ; Structure-Activity Relationship ; Transcription Factors/chemistry/*metabolism ; Vibrio parahaemolyticus/*physiology ; }, abstract = {The marine bacterium and human pathogen Vibrio parahaemolyticus rapidly colonizes surfaces by using swarming motility and forming robust biofilms. Entering one of the two colonization programs, swarming motility or sessility, involves differential regulation of many genes, resulting in a dramatic shift in physiology and behavior. V. parahaemolyticus has evolved complex regulation to control these two processes that have opposing outcomes. One mechanism relies on the balance of the second messenger c-di-GMP, where high c-di-GMP favors biofilm formation. V. parahaemolyticus possesses four homologous regulators, the Scr transcription factors, that belong in a Vibrio-specific family of W[F/L/M][T/S]R motif transcriptional regulators, some members of which have been demonstrated to bind c-di-GMP. In this work, we explore the role of these Scr regulators in biofilm development. We show that each protein binds c-di-GMP, that this binding requires a critical R in the binding motif, and that the biofilm-relevant activities of CpsQ, CpsS, and ScrO but not ScrP are dependent upon second messenger binding. ScrO and CpsQ are the primary drivers of biofilm formation, as biofilms are eliminated when both of these regulators are absent. ScrO is most important for capsule expression. CpsQ is most important for RTX-matrix protein expression, although it contributes to capsule expression when c-di-GMP levels are high. Both regulators contribute to O-antigen ligase expression. ScrP works oppositely in a minor role to repress the ligase gene. CpsS plays a regulatory checkpointing role by negatively modulating expression of these biofilm-pertinent genes under fluctuating c-di-GMP conditions. Our work further elucidates the multifactorial network that contributes to biofilm development in V. parahaemolyticusIMPORTANCEVibrio parahaemolyticus can inhabit open ocean, chitinous shells, and the human gut. Such varied habitats and the transitions between them require adaptable regulatory networks controlling energetically expensive behaviors, including swarming motility and biofilm formation, which are promoted by low and high concentrations of the signaling molecule c-di-GMP, respectively. Here, we describe four homologous c-di-GMP-binding Scr transcription factors in V. parahaemolyticus Members of this family of regulators are present in many vibrios, yet their numbers and the natures of their activities differ across species. Our work highlights the distinctive roles that these transcription factors play in dynamically controlling biofilm formation and architecture in V. parahaemolyticus and serves as a powerful example of regulatory network evolution and diversification.}, } @article {pmid31931228, year = {2020}, author = {Paniagua, AT and Paranjape, K and Hu, M and Bédard, E and Faucher, SP}, title = {Impact of temperature on Legionella pneumophila, its protozoan host cells, and the microbial diversity of the biofilm community of a pilot cooling tower.}, journal = {The Science of the total environment}, volume = {712}, number = {}, pages = {136131}, doi = {10.1016/j.scitotenv.2019.136131}, pmid = {31931228}, issn = {1879-1026}, mesh = {Biofilms ; *Legionella pneumophila ; RNA, Ribosomal, 16S ; Temperature ; Water Microbiology ; }, abstract = {Legionella pneumophila is a waterborne bacterium known for causing Legionnaires' Disease, a severe pneumonia. Cooling towers are a major source of outbreaks, since they provide ideal conditions for L. pneumophila growth and produce aerosols. In such systems, L. pneumophila typically grow inside protozoan hosts. Several abiotic factors such as water temperature, pipe material and disinfection regime affect the colonization of cooling towers by L. pneumophila. The local physical and biological factors promoting the growth of L. pneumophila in water systems and its spatial distribution are not well understood. Therefore, we built a lab-scale cooling tower to study the dynamics of L. pneumophila colonization in relationship to the resident microbiota and spatial distribution. The pilot was filled with water from an operating cooling tower harboring low levels of L. pneumophila. It was seeded with Vermamoeba vermiformis, a natural host of L. pneumophila, and then inoculated with L. pneumophila. After 92 days of operation, the pilot was disassembled, the water was collected, and biofilm was extracted from the pipes. The microbiome was studied using 16S rRNA and 18S rRNA genes amplicon sequencing. The communities of the water and of the biofilm were highly dissimilar. The relative abundance of Legionella in water samples reached up to 11% whereas abundance in the biofilm was extremely low (≤0.5%). In contrast, the host cells were mainly present in the biofilm. This suggests that L. pneumophila grows in host cells associated with biofilm and is then released back into the water following host cell lysis. In addition, water temperature shaped the bacterial and eukaryotic community of the biofilm, indicating that different parts of the systems may have different effects on Legionella growth.}, } @article {pmid31931147, year = {2020}, author = {Britt, NS and Hazlett, DS and Horvat, RT and Liesman, RM and Steed, ME}, title = {Activity of pulmonary vancomycin exposures versus planktonic and biofilm isolates of methicillin-resistant Staphylococcus aureus from cystic fibrosis sputum.}, journal = {International journal of antimicrobial agents}, volume = {55}, number = {4}, pages = {105898}, pmid = {31931147}, issn = {1872-7913}, support = {P20 GM104936/GM/NIGMS NIH HHS/United States ; TL1 TR000120/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cystic Fibrosis/*microbiology ; Drug Resistance, Multiple, Bacterial/*genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics ; Microbial Sensitivity Tests ; Respiratory System/microbiology ; Sputum/microbiology ; Vancomycin/*pharmacology ; }, abstract = {Vancomycin is commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA) infections in patients with cystic fibrosis (CF) lung disease. However, there are limited data to support the in vitro activity of this agent against MRSA isolated from CF sputum. The primary objective of this study was to evaluate the activity of vancomycin at pulmonary concentrations (intravenous and inhaled) against four clinical MRSA CF sputum isolates in planktonic and biofilm time-kill (TK) experiments. Vancomycin minimum inhibitory concentrations (MICs) were determined for these isolates at standard inoculum (SI) (~10[6] CFU/mL) and high inoculum (HI) (~10[8] CFU/mL) as well as in biofilms cultivated using physiological medium representing the microenvironment of the CF lung. Vancomycin concentrations of 10, 25, 100 and 275 µg/mL were evaluated in TK experiments against planktonic MRSA at varying inocula and versus biofilm MRSA. Vancomycin MICs increased from 0.5 µg/mL when tested at SI to 8-16 µg/mL at HI. Vancomycin MICs were further increased to 16-32 µg/mL in biofilm studies. In TK experiments, vancomycin displayed bactericidal activity (≥3 log10 killing at 24 h) against 1/4 and 0/4 planktonic MRSA isolates at SI and HI, respectively, whereas vancomycin was bactericidal against 0/4 isolates against MRSA biofilms. Based on these findings, vancomycin monotherapy appears unlikely to eradicate MRSA from the respiratory tract of patients with CF, even at high concentrations similar to those observed with inhaled therapy. Novel vancomycin formulations with enhanced biofilm penetration or combination therapy with other potentially synergistic agents should be explored.}, } @article {pmid31931057, year = {2020}, author = {Thinakaran, S and Loordhuswamy, A and Venkateshwapuram Rengaswami, G}, title = {Electrophoretic deposition of chitosan/nano silver embedded micro sphere on centrifugal spun fibrous matrices - A facile biofilm resistant biocompatible material.}, journal = {International journal of biological macromolecules}, volume = {148}, number = {}, pages = {68-78}, doi = {10.1016/j.ijbiomac.2020.01.086}, pmid = {31931057}, issn = {1879-0003}, mesh = {Bandages ; Biocompatible Materials/*chemistry ; Biofilms/*drug effects ; Chitosan/*chemistry ; Electrophoresis ; Metal Nanoparticles/*chemistry ; Polyesters/*chemistry ; Silver/*chemistry ; }, abstract = {Micro fibrous polycaprolactone (PCL) mat generally used for biomedical application was produced by facile centrifugal spinning system (C-Spin). The produced mat exhibited good structural integrity and good flexibility. The developed mat was used as substrate for electrophoretic deposition (EPD) of chitosan and polyethylene glycol (PEG) along with silver nano particles (AgNPs). During the EPD process, polymeric micro spheres embedded with silver nano particles were formed and deposited on the C-Spun substrates and the size of AgNPs were found to be around 15 nm. Surface topography of all coated samples were analyzed and found that the deposition was neat and uniform. Swelling behavior of the coated substrates were studied and found that CS/HMP/AgNPs coated substrates showed 274% swelling compared to their own dry weight. Release profile of silver nanoparticles confirmed that initial burst release followed by sustained release for CS/HMP/AgNPs coated substrates and this might be attributed to the hydrophilicity and high swellability of HMP. All AgNPs coated samples were completely prevent the bacterial biofilm formation and CS/HMP/AgNPs showed better reduction in bacterial growth on matured biofilm model. Cell proliferation studies confirmed that CS/HMP/AgNPs is biocompatible and can be used as a wound dressing material.}, } @article {pmid31930132, year = {2019}, author = {Lucio-Sauceda, DG and Urrutia-Baca, VH and Gomez-Flores, R and De La Garza-Ramos, MA and Tamez-Guerra, P and Orozco-Flores, A}, title = {Antimicrobial and Anti-Biofilm Effect of an Electrolyzed Superoxidized Solution at Neutral-pH against Helicobacter pylori.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {6154867}, pmid = {31930132}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Cell Line, Tumor ; Fibroblasts/microbiology ; Gingiva/microbiology ; Helicobacter Infections ; Helicobacter pylori/*drug effects ; Humans ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests/methods ; Mouthwashes/*pharmacology ; }, abstract = {The presence of Helicobacter pylori in the oral cavity has been associated to the failure of antimicrobial therapy in patients with gastrointestinal infection and the development of oral diseases. However, it has been reported that the maintenance of good oral hygiene can improve the therapeutic success rates, where the use of mouthwashes with anti-Helicobacter activity would help to achieve it. The aim was to evaluate the antimicrobial activity of OxOral® mouthwash against H. pylori and its effect on biofilm formation. The minimum inhibitory concentration (MIC) of OxOral® (pH = 6.4-7.5, ORP = 650-900 mV) against H. pylori was calculated testing serial dilutions 0.117-15 ppm against 1 × 10[8] CFU/mL of H. pylori (ATCC® 700824™) by broth microdilution method using 96-well plates. The H. pylori biofilm formation was determined by the optical density measurement at 600 nm from coverslips stained with 0.1% crystal violet. The gene expression of ureA, luxS, flaA, omp18, and lpxD were analyzed by RT-qPCR. OxOral® cytotoxicity was evaluated in a human gingival fibroblast cell line by MTT assay. MIC was of 3.75 ppm, with 99.7 ± 7.7% bacterial growth inhibition. In the negative control, the biofilm formation was observed, whereas when bacteria were treated with OxOral® at 0.234, 0.469, and 0.938 ppm, an inhibition of 35.5 ± 0.9%, 89.1 ± 1.2%, and 99.9 ± 5.5% were obtained, respectively. The gene expression analysis showed that flaA, omp18, and lpxD genes were down-regulated with OxOral® compared with control (p < 0.05). Low cytotoxicity of 16.5 ± 7.6% was observed at the highest dose (15 ppm); no significant differences were observed from 15 to 0.469 ppm compared to the control of untreated cells (p > 0.05). Our results reveal an important anti-Helicobacter activity of OxOral® and open the possibility of its therapeutic use new studies, which would increase the success rate of conventional therapies against H. pylori.}, } @article {pmid31929848, year = {2019}, author = {Avila-Novoa, MG and Solís-Velázquez, OA and Rangel-López, DE and González-Gómez, JP and Guerrero-Medina, PJ and Gutiérrez-Lomelí, M}, title = {Biofilm Formation and Detection of Fluoroquinolone- and Carbapenem-Resistant Genes in Multidrug-Resistant Acinetobacter baumannii.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2019}, number = {}, pages = {3454907}, pmid = {31929848}, issn = {1712-9532}, abstract = {Acinetobacter baumannii is an important opportunistic pathogen that shows resistance to cephalosporins, penicillins, carbapenems, fluoroquinolones, and aminoglycosides, the multiresistance being associated with its ability to form biofilms in clinical environments. The aim of this study was to determine biofilm formation and its potential association with genes involved in antibiotic resistance mechanisms of A. baumannii isolates of different clinical specimens. We demonstrated 100% of the A. baumannii isolates examined to be multidrug resistant (MDR), presenting a 73.3% susceptibility to cefepime and a 53.3% susceptibility to ciprofloxacin. All A. baumannii isolates were positive for bla OXA-51, 33.3% being positive for bla OXA-23 and ISAba1, and 73.3% being positive for gyrA. We found 86.6% of A. baumannii strains to be low-grade biofilm formers and 13.3% to be biofilm negative; culturing on Congo red agar (CRA) plates revealed that 73.3% of the A. baumannii isolates to be biofilm producers, while 26.6% were not. These properties, combined with the role of A. baumannii as a nosocomial pathogen, increase the probability of A. baumannii causing nosocomial infections and outbreaks as a complication during therapeutic treatments and emphasize the need to control A. baumannii biofilms in hospital environments.}, } @article {pmid31929046, year = {2020}, author = {Obata, O and Salar-Garcia, MJ and Greenman, J and Kurt, H and Chandran, K and Ieropoulos, I}, title = {Development of efficient electroactive biofilm in urine-fed microbial fuel cell cascades for bioelectricity generation.}, journal = {Journal of environmental management}, volume = {258}, number = {}, pages = {109992}, pmid = {31929046}, issn = {1095-8630}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Sewage ; }, abstract = {The Microbial fuel cell (MFC) technology harnesses the potential of some naturally occurring bacteria for electricity generation. Digested sludge is commonly used as the inoculum to initiate the process. There are, however, health hazards and practical issues associated with the use of digested sludge depending on its origin as well as the location for system deployment. This work reports the development of an efficient electroactive bacterial community within ceramic-based MFCs fed with human urine in the absence of sludge inoculum. The results show the development of a uniform bacterial community with power output levels equal to or higher than those generated from MFCs inoculated with sludge. In this case, the power generation begins within 2 days of the experimental set-up, compared to about 5 days in some sludge-inoculated MFCs, thus significantly reducing the start-up time. The metagenomics analysis of the successfully formed electroactive biofilm (EAB) shows significant shifts between the microbial ecology of the feeding material (fresh urine) and the developed anodic biofilm. A total of 21 bacteria genera were detected in the urine feedstock whilst up to 35 different genera were recorded in the developed biofilm. Members of Pseudomonas (18%) and Anaerolineaceae (17%) dominate the bacterial community of the fresh urine feed while members of Burkholderiaceae (up to 50%) and Tissierella (up to 29%) dominate the anodic EAB. These results highlight a significant shift in the bacterial community of the feedstock towards a selection and adaptation required for the various electrochemical reactions essential for survival through power generation.}, } @article {pmid31928337, year = {2021}, author = {Trojanowicz, K and Plaza, E}, title = {Combining numerical simulation with response surface modelling for optimization of reject water partial nitritation/anammox in moving bed biofilm reactor.}, journal = {Environmental technology}, volume = {42}, number = {18}, pages = {2823-2835}, doi = {10.1080/09593330.2020.1714747}, pmid = {31928337}, issn = {1479-487X}, mesh = {*Ammonium Compounds ; *Biofilms ; Bioreactors ; Nitrogen ; Oxidation-Reduction ; Wastewater ; Water ; }, abstract = {Optimization of a single-stage, partial nitritation/anammox (PN/A) process for a reject water treatment in a continuous-flow, moving bed biofilm reactor (MBBR) was presented. Response surface method (RSM) was combined with simulation experiments conducted with the validated mathematical model of PN/A in MBBR. The total inorganic nitrogen (TIN) removal efficiency was the response parameter. Eight independent variables were taken into consideration: reject water flow rate (Q), inflow concentrations of the total ammonium nitrogen (TAN), chemical oxygen demand (COD), alkalinity (ALK), pH, temperature (T), dissolved oxygen concentration in the bulk liquid (DO) and aeration time within 60 min intermittent aeration cycle (AERON). Eleven interactions between independent variables were found as significant (p < 0.05). The interaction of AERON*DO had the highest impact on the PN/A process. Optimal values of the controlled variables were found for two cases of MBBR operation. Verification of the optimization was done by the simulation and comparison with the data from the empirical experiments. Under the conditions of the fixed hydraulic retention time of about 38 h, volumetric nitrogen loading rate of 0.48 kgN/m[3]d, T of 22.5°C, TAN of 750 gN/m[3] and optimized values of DO = 3.0 gO2/m[3], AERON = 0.54 h, pH = 7.5, ALK = 80 molHCO3/m[3], COD = 775 gO2/m[3], the predicted TINrem was 78% which is consistent with PN/A performance observed in the technical-scale MBBR systems.}, } @article {pmid31928216, year = {2020}, author = {Liu, C and Zhu, L and Chen, L}, title = {Mechanism of biofilm formation on a hydrophobic polytetrafluoroethylene membrane during the purification of surface water using direct contact membrane distillation (DCMD), with especial interest in the feed properties.}, journal = {Biofouling}, volume = {36}, number = {1}, pages = {14-31}, doi = {10.1080/08927014.2019.1710136}, pmid = {31928216}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Biofouling/*prevention & control ; China ; *Distillation ; *Fresh Water/chemistry/microbiology ; Hydrophobic and Hydrophilic Interactions ; Lakes/chemistry/microbiology ; *Membranes, Artificial ; Polytetrafluoroethylene/*chemistry ; Rivers/chemistry/microbiology ; Surface Properties ; Water Purification/instrumentation/*methods ; Water Quality ; }, abstract = {The impact of feed water quality on biofilm formation during membrane distillation (MD) was investigated in this study, particularly emphasizing the interrelationship between organics, salts, and microbes. Two types of typical natural surface waters in Nanjing, China, were chosen as feed solutions for long-term MD operation, including the Qinhuai River and Xuanwu Lake. The biofilms that developed under different feed water qualities exhibited distinct Foulant compositions and structures, causing different flux decline trends for the MD system. Accordingly, two typical patterns of biofilm formation were suggested for the MD operation of the two different kinds of surface waters in this study. Organics from a primal feed solution and dead bacteria were the key to the establishment of a biofilm on the membrane, and this needs to be effectively removed from the MD system through pre-treatment and process control strategies. Finally, a feasible strategy for MD biofouling control was suggested.}, } @article {pmid31927950, year = {2020}, author = {Dong, H and Zhang, W and Wang, Y and Liu, D and Wang, P}, title = {Biofilm Polysaccharide Display Platform: A Natural, Renewable, and Biocompatible Material for Improved Lipase Performance.}, journal = {Journal of agricultural and food chemistry}, volume = {68}, number = {5}, pages = {1373-1381}, doi = {10.1021/acs.jafc.9b07209}, pmid = {31927950}, issn = {1520-5118}, mesh = {Biocatalysis ; Biocompatible Materials/*chemistry ; *Biofilms ; Clostridium acetobutylicum/*chemistry/physiology ; Enzyme Stability ; Enzymes, Immobilized/chemistry/metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Lipase/chemistry/*metabolism ; Polysaccharides/*chemistry/metabolism ; }, abstract = {Most of the microorganisms can form biofilms, which makes biofilms an abundant bioresource to be exploited. Due to the limitations of the application of current immobilization methods for biofilms, we developed an immobilization method called the biofilm polysaccharide display (BPD) strategy while maintaining the native biofilm structure and catalytic microenvironment of Clostridium acetobutylicum B3. Lipase Lip181 showed significant improvements in stability after chemical immobilization. For example, immobilized Lip181 retained 74.23% of its original activity after incubation for 14 days, while free Lip181 was totally deactivated. In addition, immobilized Lip181 maintained high residual activity (pH 5.0-11.0), which showed improved resistance to pH changes. Notably, this method did not decrease but slightly increased the relative activity of Lip181 from 6.39 to 6.78 U/mg. Immobilized Lip181 was used to prepare cinnamyl acetate, and it showed a maximum yield of 85.09%. Overall, this biofilm immobilization method may promote the development of biocatalytic and biofilm materials.}, } @article {pmid31927762, year = {2020}, author = {Paluch, E and Rewak-Soroczyńska, J and Jędrusik, I and Mazurkiewicz, E and Jermakow, K}, title = {Prevention of biofilm formation by quorum quenching.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {5}, pages = {1871-1881}, pmid = {31927762}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/genetics ; Bacterial Physiological Phenomena/drug effects ; Bacterial Proteins/genetics/metabolism ; *Biofilms/drug effects ; *Quorum Sensing/drug effects ; Virulence Factors/genetics/metabolism ; }, abstract = {Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.}, } @article {pmid31927753, year = {2020}, author = {Akoğlu, A}, title = {The effect of some environmental conditions on planktonic growth and biofilm formation by some lactic acid bacteria isolated from a local cheese in Turkey.}, journal = {Biotechnology letters}, volume = {42}, number = {3}, pages = {481-492}, doi = {10.1007/s10529-020-02794-4}, pmid = {31927753}, issn = {1573-6776}, mesh = {Biofilms/*growth & development ; Cheese/*microbiology ; Enterococcus/*physiology ; Enterococcus faecalis/*physiology ; *Food Microbiology ; Plankton ; Turkey ; }, abstract = {OBJECTIVE: The purpose of this study was to determine the effect of some environmental conditions (different temperature degrees and pH values, different salt, glucose and lactose concentrations) on the planktonic growth and biofilm formation ability of the lactic acid bacteria (LAB) isolated from a local cheese in Turkey.

RESULTS: It was determined that Enterococcus lactis EC61 and Enterococcus faecalis EC41 are the most resistant bacteria to the changing environmental conditions and they can stably maintain their planktonic growth in the pH values of 6.5, 7.0, 7.5, and 8.0; in the salt concentrations of 4% and 6.5%; in the glucose concentration of 0.5%; and in the lactose concentrations of 0.5%, 1.5%, and 2.5%. It was found that all strains had the biofilm formation ability and especially the biofilm formation of Enterococcus lactis EC61 and Enterococcus faecalis EC41 strains significantly increased in the acidic pH values and in the increasing glucose and lactose concentrations, and significantly decreased in the increasing salt concentration.

CONCLUSIONS: When considered in terms of LAB potential as a starter culture, specifying the effect of some environmental conditions on the planktonic growth and biofilm formation ability is important for the food industry. As a conclusion, it was determined that lactic acid bacteria, which were previously determined to have some starter culture characteristics, had additional properties on the way to being an starter culture.}, } @article {pmid31927517, year = {2020}, author = {Hasan, ME and Shahriar, A and Shams, F and Nath, AK and Emran, TB}, title = {Correlation between biofilm formation and antimicrobial susceptibility pattern toward extended spectrum β-lactamase (ESBL)- and non-ESBL-producing uropathogenic bacteria.}, journal = {Journal of basic and clinical physiology and pharmacology}, volume = {32}, number = {2}, pages = {}, doi = {10.1515/jbcpp-2019-0296}, pmid = {31927517}, issn = {2191-0286}, abstract = {BACKGROUND: Urinary tract infections (UTIs) are the most common bacterial infection encountered worldwide and are associated with significant morbidity and mortality.

METHODS: The present study was undertaken to investigate the biofilm-forming ability, antibiotic susceptibility patterns and extended spectrum β-lactamase (ESBL) production of seven uropathogenic isolates comprising both Escherichia coli and Klebsiella pneumoniae. The morphological, cultural and biochemical tests for the identification of the isolates, antibiotic susceptibility test, detection of ESBL production, biofilm formation on 96-well microtiter plate and Congo red agar (CRA) media are performed.

RESULTS: The antimicrobial susceptibility profiles obtained in this study showed that the most active drugs gentamicin, amikacin and imipenem (100% sensitivity) were followed by amoxicillin-clavulanic acid (85% sensitivity), co-trimoxazole, ciprofloxacin (57% sensitivity) ceftazidime and kanamycin (50% sensitivity). All the isolates showed resistance to amoxicillin followed by ceftriaxone and cefotaxime (71% resistance), and the scenario gets more complicated because of the production of ESBL by five isolates (three E. coli isolates and two K. pneumoniae). The strains were also able to form biofilm as tested on CRA medium and by microtiter plate assay. The correlation between ESBL, non-ESBL and biofilm-producing E. coli and K. pneumonia was determined along with the multiple drug resistance patterns of E. coli and K. pneumonia.

CONCLUSIONS: The findings of the study indicate that the emergence and rapid spread of such multidrug-resistant pathogens are of great concern. Early detection of ESBL-producing pathogen is of paramount clinical importance; therefore, strict infection control practices as well as therapeutic guidance for confirmed infection can be rapidly initiated.}, } @article {pmid31924268, year = {2020}, author = {Kamali, E and Jamali, A and Ardebili, A and Ezadi, F and Mohebbi, A}, title = {Evaluation of antimicrobial resistance, biofilm forming potential, and the presence of biofilm-related genes among clinical isolates of Pseudomonas aeruginosa.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {27}, pmid = {31924268}, issn = {1756-0500}, support = {110212//Golestan University of Medical Sciences/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial/drug effects/*genetics ; Female ; *Genes, Bacterial ; Humans ; Male ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/drug effects/*genetics/*isolation & purification ; }, abstract = {OBJECTIVES: Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated.

RESULTS: A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-lactam (piperacillin/tazobactam or ceftazidime) and an aminoglycoside or carbapenems (imipenem, meropenem) with fluoroquinolones in conjunction with an aminoglycoside can be used against Pseudomonas infections. However, reasonable antimicrobial use and high standards of infection prevention and control are essential to prevent further development of antimicrobial resistance. Combination strategies based on the proper anti-pseudomonal antibiotics along with anti-biofilm agents can also be selected to eradicate biofilm-associated infections.}, } @article {pmid31923978, year = {2020}, author = {Tan, Y and Ma, S and Leonhard, M and Moser, D and Ludwig, R and Schneider-Stickler, B}, title = {Co-immobilization of cellobiose dehydrogenase and deoxyribonuclease I on chitosan nanoparticles against fungal/bacterial polymicrobial biofilms targeting both biofilm matrix and microorganisms.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {108}, number = {}, pages = {110499}, doi = {10.1016/j.msec.2019.110499}, pmid = {31923978}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/pharmacology ; Antifungal Agents/pharmacology ; *Biofilms ; Candida albicans/drug effects ; Carbohydrate Dehydrogenases/*chemistry ; Cell Line ; Cell Survival/drug effects ; Chitosan/*chemistry ; Deoxyribonuclease I/*chemistry ; Enzymes, Immobilized/chemistry ; Extracellular Polymeric Substance Matrix ; Humans ; Keratinocytes/cytology/*microbiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Nanoparticles/chemistry ; Silicones/chemistry ; Staphylococcus aureus/drug effects ; Trichoderma/drug effects ; }, abstract = {Polymicrobial biofilm related infections have been a major threat in health care. In this study, the co-immobilization of cellobiose dehydrogenase (CDH) and deoxyribonuclease I (DNase) on positively charged chitosan nanoparticles (CSNPs) resulted in a bi-functional nanoparticle (CSNP-DNase-CDH) targeting both biofilm matrix and microorganisms. The in-vitro antibiofilm activities of CSNPs against monomicrobial and polymicrobial biofilms of Candida albicans and Staphylococcus aureus were evaluated. The results showed that CSNPs were able to penetrate across the matrix of biofilms and interfere with embedded microbial cells. CSNP-DNase-CDH exhibited a higher activity than CSNPs loaded with only DNase or CDH for inhibiting monomicrobial and polymicrobial biofilm formation as well as for disrupting pre-formed biofilms. Furthermore, CSNP-DNase-CDH could disrupt the biofilm formation through degradation of eDNA, reduce biofilm thickness, and kill microbial cells on silicone. The bi-functional CSNP is applicable for the protection of medical devices from polymicrobial biofilms or the treatment of device associated infections.}, } @article {pmid31923962, year = {2020}, author = {Mahamuni-Badiger, PP and Patil, PM and Badiger, MV and Patel, PR and Thorat-Gadgil, BS and Pandit, A and Bohara, RA}, title = {Biofilm formation to inhibition: Role of zinc oxide-based nanoparticles.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {108}, number = {}, pages = {110319}, doi = {10.1016/j.msec.2019.110319}, pmid = {31923962}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/chemistry ; Bacteria/*growth & development ; Bacterial Infections/prevention & control ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Humans ; Nanoparticles/*chemistry ; Prostheses and Implants/*microbiology ; Zinc Oxide/*chemistry ; }, abstract = {Zinc oxide nanoparticles have received much attention worldwide as they possess unique properties like varied morphology, large surface area to volume ratio, potent antibacterial activity, and biocompatibility. Biofilm contains homogenous or heterogeneous microorganisms that remain enclosed in a matrix of an extracellular polymeric substance on biotic or abiotic surfaces. Bacterial biofilm formed on medical devices such as central venous catheters, urinary catheters, prosthetic joints, cardiovascular implantable devices, dental implants, contact lenses, intrauterine contraceptive devices and breast implants cause persistent infections. Such biofilm-associated infections in medical implants cause serious problems for public health and affect the function of medical implants. So, there is an urgent need for the use of an antimicrobial agent that will inhibit biofilm, including such antibiotic-resistant bacterial strains as bacteria, to develop multiple drug-resistances resulting in failure of the antibiotic's action. The antimicrobial agent used should be ideal in terms of biocompatibility, antimicrobial activity, stability at different environmental conditions, with less sensitivity to the development of resistance towards micro-organisms, safe for in vivo and in vitro use, and remain non-hazardous to the environment, etc. The first objective of the review discusses the insights into the formation of biofilm on a medical device with the current strategies to inhibit. The second purpose is to review the recent progress in ZnO- based nanostructure including composites for antibacterial and anti-biofilm activities. This will offer a new opportunity for the application of Zinc oxide-based material in the prevention of biofilm on the medical devices.}, } @article {pmid31922722, year = {2020}, author = {Elbourne, A and Cheeseman, S and Atkin, P and Truong, NP and Syed, N and Zavabeti, A and Mohiuddin, M and Esrafilzadeh, D and Cozzolino, D and McConville, CF and Dickey, MD and Crawford, RJ and Kalantar-Zadeh, K and Chapman, J and Daeneke, T and Truong, VK}, title = {Antibacterial Liquid Metals: Biofilm Treatment via Magnetic Activation.}, journal = {ACS nano}, volume = {14}, number = {1}, pages = {802-817}, doi = {10.1021/acsnano.9b07861}, pmid = {31922722}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Gallium/chemistry/*pharmacology ; Magnetic Phenomena ; Microbial Sensitivity Tests ; Particle Size ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; Surface Properties ; }, abstract = {Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.}, } @article {pmid31922015, year = {2018}, author = {Vergalito, F and Pietrangelo, L and Petronio Petronio, G and Colitto, F and Alfio Cutuli, M and Magnifico, I and Venditti, N and Guerra, G and Di Marco, R}, title = {Vitamin E for Prevention of Biofilm-caused Healthcare-associated Infections.}, journal = {Open medicine (Warsaw, Poland)}, volume = {15}, number = {}, pages = {14-21}, pmid = {31922015}, issn = {2391-5463}, abstract = {The healthcare-associated infections (HCAIs) occur in patients both in nosocomial environments and in community. More often HCAIs are associated to the use of medical devices and bacterial biofilm development on these equipments. Due to the clinical and economic relevance of this topic, new strategies for the treatment of infections caused by biofilm proliferation are unceasingly searched by scientists. The present study investigated the role of vitamin E to reduce the biofilm formation for a larger panel of human pathogens, including strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter baumannii, Pseudomonas aeruginosa and Pseudomonas putida. This potential activity was tested by placing a preparation of vitamin E (α-Tocopheryl acetate) as interface between the bacterial culture and the polystyrene walls of a 96 well plate at different concentrations of glucose, used as a biofilm enhancer. The Staphylococcus genus was further investigated by spreading the vitamin E on a silicone catheter lumen and evaluating its influence on the bacterial colonization. From our results, vitamin E has been able to interfere with bacterial biofilm and prevent in vitro biofilm formation. Furthermore, the ability of Staphylococcus aureus and Staphylococcus epidermidis to colonize the catheter surface decreased as a result of vitamin E application.}, } @article {pmid31921707, year = {2019}, author = {Ng, HM and Slakeski, N and Butler, CA and Veith, PD and Chen, YY and Liu, SW and Hoffmann, B and Dashper, SG and Reynolds, EC}, title = {The Role of Treponema denticola Motility in Synergistic Biofilm Formation With Porphyromonas gingivalis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {432}, pmid = {31921707}, issn = {2235-2988}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Chronic Periodontitis/microbiology ; Gene Deletion ; Genome, Bacterial/genetics ; Humans ; Locomotion/genetics/physiology ; Microbial Interactions/physiology ; Porphyromonas gingivalis/*growth & development ; Treponema denticola/*genetics/growth & development/pathogenicity ; Virulence Factors/genetics/metabolism ; Whole Genome Sequencing ; }, abstract = {Chronic periodontitis has a polymicrobial biofilm etiology and interactions between key oral bacterial species, such as Porphyromonas gingivalis and Treponema denticola contribute to disease progression. P. gingivalis and T. denticola are co-localized in subgingival plaque and have been previously shown to exhibit strong synergy in growth, biofilm formation and virulence in an animal model of disease. The motility of T. denticola, although not considered as a classic virulence factor, may be involved in synergistic biofilm development between P. gingivalis and T. denticola. We determined the role of T. denticola motility in polymicrobial biofilm development using an optimized transformation protocol to produce two T. denticola mutants targeting the motility machinery. These deletion mutants were non-motile and lacked the gene encoding the flagellar hook protein of the periplasmic flagella (ΔflgE) or a component of the stator motor that drives the flagella (ΔmotB). The specificity of these gene deletions was determined by whole genome sequencing. Quantitative proteomic analyses of mutant strains revealed that the specific inactivation of the motility-associated gene, motB, had effects beyond motility. There were 64 and 326 proteins that changed in abundance in the ΔflgE and ΔmotB mutants, respectively. In the ΔflgE mutant, motility-associated proteins showed the most significant change in abundance confirming the phenotype change for the mutant was related to motility. However, the inactivation of motB as well as stopping motility also upregulated cellular stress responses in the mutant indicating pleiotropic effects of the mutation. T. denticola wild-type and P. gingivalis displayed synergistic biofilm development with a 2-fold higher biomass of the dual-species biofilms than the sum of the monospecies biofilms. Inactivation of T. denticola flgE and motB reduced this synergy. A 5-fold reduction in dual-species biofilm biomass was found with the motility-specific ΔflgE mutant suggesting that T. denticola periplasmic flagella are essential in synergistic biofilm formation with P. gingivalis.}, } @article {pmid31921010, year = {2019}, author = {Durgadevi, R and Abirami, G and Alexpandi, R and Nandhini, K and Kumar, P and Prakash, S and Veera Ravi, A}, title = {Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2804}, pmid = {31921010}, issn = {1664-302X}, abstract = {Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.}, } @article {pmid31921008, year = {2019}, author = {Wang, J and Jiao, H and Meng, J and Qiao, M and Du, H and He, M and Ming, K and Liu, J and Wang, D and Wu, Y}, title = {Baicalin Inhibits Biofilm Formation and the Quorum-Sensing System by Regulating the MsrA Drug Efflux Pump in Staphylococcus saprophyticus.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2800}, pmid = {31921008}, issn = {1664-302X}, abstract = {Staphylococcus saprophyticus (S. saprophyticus) is one of the main pathogens that cause serious infection due to its acquisition of antibiotic resistance. The efflux pump decreases antibiotic abundance, and biofilm compromises the penetration of antibiotics. It has been reported that baicalin is a potential agent to inhibit efflux pumps, biofilm formation, and quorum-sensing systems. The purpose of this study was to investigate whether baicalin can inhibit S. saprophyticus biofilm formation and the quorum-sensing system by inhibiting the MsrA efflux pump. First, the mechanism of baicalin inhibiting efflux was investigated by the ethidium bromide (EtBr) efflux assay, measurement of ATP content, and pyruvate kinase (PK) activities. These results revealed that baicalin significantly reduced the efflux of EtBr, the ATP content, and the activity of PK. Moreover, its role in biofilm formation and the agr system was studied by crystal violet staining, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction. These results showed that baicalin decreased biofilm formation, inhibited bacterial aggregation, and downregulated mRNA transcription levels of the quorum-sensing system regulators agrA, agrC, RNAIII, and sarA. Correlation analysis indicated that there was a strong positive correlation between the efflux pump and biofilm formation and the agr system. We demonstrate for the first time that baicalin inhibits biofilm formation and the agr quorum-sensing system by inhibiting the efflux pump in S. saprophyticus. Therefore, baicalin is a potential therapeutic agent for S. saprophyticus biofilm-associated infections.}, } @article {pmid31919364, year = {2020}, author = {Dieltjens, L and Appermans, K and Lissens, M and Lories, B and Kim, W and Van der Eycken, EV and Foster, KR and Steenackers, HP}, title = {Inhibiting bacterial cooperation is an evolutionarily robust anti-biofilm strategy.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {107}, pmid = {31919364}, issn = {2041-1723}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Drug Resistance, Bacterial/genetics/physiology ; Extracellular Polymeric Substance Matrix/drug effects/*metabolism ; Imidazoles/*pharmacology ; Salmonella typhimurium/genetics/*growth & development ; }, abstract = {Bacteria commonly form dense biofilms encased in extracellular polymeric substances (EPS). Biofilms are often extremely tolerant to antimicrobials but their reliance on shared EPS may also be a weakness as social evolution theory predicts that inhibiting shared traits can select against resistance. Here we show that EPS of Salmonella biofilms is a cooperative trait whose benefit is shared among cells, and that EPS inhibition reduces both cell attachment and antimicrobial tolerance. We then compare an EPS inhibitor to conventional antimicrobials in an evolutionary experiment. While resistance against conventional antimicrobials rapidly evolves, we see no evolution of resistance to EPS inhibition. We further show that a resistant strain is outcompeted by a susceptible strain under EPS inhibitor treatment, explaining why resistance does not evolve. Our work suggests that targeting cooperative traits is a viable solution to the problem of antimicrobial resistance.}, } @article {pmid31917539, year = {2020}, author = {Eddenden, A and Kitova, EN and Klassen, JS and Nitz, M}, title = {An Inactive Dispersin B Probe for Monitoring PNAG Production in Biofilm Formation.}, journal = {ACS chemical biology}, volume = {15}, number = {5}, pages = {1204-1211}, doi = {10.1021/acschembio.9b00907}, pmid = {31917539}, issn = {1554-8937}, support = {89708//CIHR/Canada ; }, mesh = {Aggregatibacter actinomycetemcomitans/metabolism ; Bacterial Proteins/*chemistry/metabolism ; *Biofilms ; Catalytic Domain ; Cell Aggregation ; Cell Membrane/metabolism/ultrastructure ; Escherichia coli/physiology ; Fluorescent Dyes/chemistry/metabolism ; Glycoside Hydrolases/*chemistry/metabolism ; Green Fluorescent Proteins/chemistry ; Mutation ; Optical Imaging ; Recombinant Proteins/*chemistry/metabolism ; Single-Cell Analysis ; beta-Glucans/*chemistry ; }, abstract = {The bacterial exopolysaccharide poly-β-1,6-N-acetylglucosamine is a major extracellular matrix component in biofilms of both Gram-positive and Gram-negative organisms. We have leveraged the specificity of the biofilm-dispersing glycoside hydrolase Dispersin B (DspB) to generate a probe (Dispersin B PNAG probe, DiPP) for monitoring PNAG production and localization during biofilm formation. Mutation of the active site of Dispersin B gave DiPP, which was an effective probe despite its low affinity for PNAG oligosaccharides (KD ∼ 1-10 mM). Imaging of PNAG-dependent and -independent biofilms stained with a fluorescent-protein fusion of DiPP (GFP-DiPP) demonstrated the specificity of the probe for the structure of PNAG on both single-cell and biofilm levels, indicating a high local concentration of PNAG at the bacterial cell surface. Through quantitative bacterial cell binding assays and confocal microscopy analysis using GFP-DiPP, discrete areas of local high concentrations of PNAG were detected on the surface of early log phase cells. These distinct areas were seen to grow, slough from cells, and accumulate in interbacterial regions over the course of several cell divisions, showing the development of a PNAG-dependent biofilm. A potential helical distribution of staining was also noted, suggesting some degree of organization of PNAG production at the cell surface prior to cell aggregation. Together, these experiments shed light on the early stages of PNAG-dependent biofilm formation and demonstrate the value of a low-affinity-high-specificity probe for monitoring the production of bacterial exopolysaccharides.}, } @article {pmid31916896, year = {2020}, author = {Araújo Lima, AV and da Silva, SM and do Nascimento Júnior, JAA and Correia, MDS and Luz, AC and Leal-Balbino, TC and da Silva, MV and Lima, JLDC and Maciel, MAV and Napoleão, TH and Oliveira, MBM and Paiva, PMG}, title = {Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {7}, pages = {802-814}, doi = {10.1089/mdr.2019.0214}, pmid = {31916896}, issn = {1931-8448}, mesh = {Acinetobacter baumannii/*drug effects/genetics ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins ; Biofilms/*drug effects ; Brazil ; DNA, Bacterial ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/*drug effects/genetics ; beta-Lactam Resistance/genetics ; }, abstract = {Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek[®]2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.}, } @article {pmid31915750, year = {2019}, author = {Samoilova, Z and Tyulenev, A and Muzyka, N and Smirnova, G and Oktyabrsky, O}, title = {Tannic and gallic acids alter redox-parameters of the medium and modulate biofilm formation.}, journal = {AIMS microbiology}, volume = {5}, number = {4}, pages = {379-392}, pmid = {31915750}, issn = {2471-1888}, abstract = {Tannic (TA) and gallic (GA) acids are known to have both anti- and prooxidant properties however recently they have been described as potential anti-biofilm agents although their mechanisms of action on bacterial cells remain obscure. The aim of our research was to elucidate the role of prooxidant actions of these plant phenolic compounds in bactericidal effects and biofilm formation. In our experiments, both compounds demonstrated strong oxidative properties that altered activity of stress regulons and contributed to decrease of CFU and ability of cells to maintain membrane potential. Stimulation of biofilm formation was observed in all the strains with the exception of the strains deficient in flagella synthesis. Both compounds demonstrated bactericidal effect which was weakened in biofilms. TA efficiently killed bacteria in the bioflms of pgaA mutant which pointed out an important role of poly-beta-1,6-N-acetyl-D-glucosamine (PGA) polysaccharide in matrix formation. Similar effects of TA in recA mutant indicate involvement of SOS-response into reaction towards exposure with TA. Gallic acid-induced killing was more pronounced in the biofilms of csgA mutant revealing role of curli in protection against GA toxicity.}, } @article {pmid31913459, year = {2020}, author = {Oanh, NT and Duc, HD and Ngoc, DTH and Thuy, NTD and Hiep, NH and Van Hung, N}, title = {Biodegradation of propanil by Acinetobacter baumannii DT in a biofilm-batch reactor and effects of butachlor on the degradation process.}, journal = {FEMS microbiology letters}, volume = {367}, number = {2}, pages = {}, doi = {10.1093/femsle/fnaa005}, pmid = {31913459}, issn = {1574-6968}, mesh = {Acetanilides/chemistry/*metabolism ; Acinetobacter baumannii/chemistry/growth & development/*metabolism ; Biodegradation, Environmental ; Biofilms ; Bioreactors/microbiology ; Herbicides/*metabolism ; Kinetics ; Propanil/chemistry/*metabolism ; }, abstract = {The herbicide, propanil, has been extensively applied in weed control, which causes serious environmental pollution. Acinetobacter baumannii DT isolated from soil has been used to determine the degradation rates of propanil and 3,4-dichloroaniline by freely suspended and biofilm cells. The results showed that the bacterial isolate could utilize both compounds as sole carbon and nitrogen sources. Edwards's model could be fitted well to the degradation kinetics of propanil, with the maximum degradation of 0.027 ± 0.003 mM h-1. The investigation of the degradation pathway showed that A. baumannii DT transformed propanil to 3,4-dichloroaniline before being completely degraded via the ortho-cleavage pathway. In addition, A. baumannii DT showed high tolerance to butachlor, a herbicide usually mixed with propanil to enhance weed control. The presence of propanil and butachlor in the liquid media increased the cell surface hydrophobicity and biofilm formation. Moreover, the biofilm reactor showed increased degradation rates of propanil and butachlor and high tolerance of bacteria to these chemicals. The obtained results showed that A. baumannii DT has a high potential in the degradation of propanil.}, } @article {pmid31911489, year = {2020}, author = {Prades, L and Fabbri, S and Dorado, AD and Gamisans, X and Stoodley, P and Picioreanu, C}, title = {Computational and Experimental Investigation of Biofilm Disruption Dynamics Induced by High-Velocity Gas Jet Impingement.}, journal = {mBio}, volume = {11}, number = {1}, pages = {}, pmid = {31911489}, issn = {2150-7511}, mesh = {*Biofilms ; *Biomechanical Phenomena ; Elasticity ; Streptococcal Infections/microbiology ; Streptococcus mutans/*physiology ; Viscosity ; }, abstract = {Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such extreme conditions, since direct measurements of viscosity at these high shear rates are not possible using dynamic testing instruments. Here, we used computational fluid dynamics simulations to assess the complex fluid interactions of ripple patterning produced by high-speed turbulent air jets impacting perpendicular to the surface of Streptococcus mutans biofilms, a dental pathogen causing caries, captured by high-speed imaging. The numerical model involved a two-phase flow of air over a non-Newtonian biofilm, whose viscosity as a function of shear rate was estimated using the Herschel-Bulkley model. The simulation suggested that inertial, shear, and interfacial tension forces governed biofilm disruption by the air jet. Additionally, the high shear rates generated by the jet impacts coupled with shear-thinning biofilm property resulted in rapid liquefaction (within milliseconds) of the biofilm, followed by surface instability and traveling waves from the impact site. Our findings suggest that rapid shear thinning under very high shear flows causes the biofilm to behave like a fluid and elasticity can be neglected. A parametric sensitivity study confirmed that both applied force intensity (i.e., high jet nozzle air velocity) and biofilm properties (i.e., low viscosity and low air-biofilm surface tension and thickness) intensify biofilm disruption by generating large interfacial instabilities.IMPORTANCE Knowledge of mechanisms promoting disruption though mechanical forces is essential in optimizing biofilm control strategies which rely on fluid shear. Our results provide insight into how biofilm disruption dynamics is governed by applied forces and fluid properties, revealing a mechanism for ripple formation and fluid-biofilm mixing. These findings have important implications for the rational design of new biofilm cleaning strategies with fluid jets, such as determining optimal parameters (e.g., jet velocity and position) to remove the biofilm from a certain zone (e.g., in dental hygiene or debridement of surgical site infections) or using antimicrobial agents which could increase the interfacial area available for exchange, as well as causing internal mixing within the biofilm matrix, thus disrupting the localized microenvironment which is associated with antimicrobial tolerance. The developed model also has potential application in predicting drag and pressure drop caused by biofilms on bioreactor, pipeline, and ship hull surfaces.}, } @article {pmid31911315, year = {2020}, author = {Islam, J and Chilkoor, G and Jawaharraj, K and Dhiman, SS and Sani, R and Gadhamshetty, V}, title = {Vitamin-C-enabled reduced graphene oxide chemistry for tuning biofilm phenotypes of methylotrophs on nickel electrodes in microbial fuel cells.}, journal = {Bioresource technology}, volume = {300}, number = {}, pages = {122642}, doi = {10.1016/j.biortech.2019.122642}, pmid = {31911315}, issn = {1873-2976}, mesh = {Ascorbic Acid ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Graphite ; Nickel ; Phenotype ; Vitamins ; }, abstract = {This study reports the use of multi-layered reduced graphene oxide (rGO) coating on porous nickel foam (NF) electrodes for enhancing biofilm growth of Rhodobacter Sphaeroides spp fed with methanol in microbial fuel cells (CH3OH-MFCs). Electrochemical methods were used to assess the methylotrophic activity on rGO/NF electrodes. The power density and current density offered by rGO/NF (1200 mW m[-2] and 680 mA m[-2]) were 220-fold and 540-fold higher compared to bare NF (5.50 mW m[-2] and 1.26 mA m[-2]), respectively. Electrochemical impedance spectroscopy results show that rGO/NF suppresses charge transfer resistance to CH3OH oxidation by 40-fold compared to the control. This improved performance is due to the ability of rGO coatings to decrease the wetting contact angle (improve the hydrophilicity) of NF from 128[0] to 0[0]. A preliminary cost analysis was carried out to assess the viability of rGO/NF electrodes via vitamin-C-enabled graphene oxide chemistry for CH3OH-MFCs applications.}, } @article {pmid31910883, year = {2020}, author = {Omidi, M and Firoozeh, F and Saffari, M and Sedaghat, H and Zibaei, M and Khaledi, A}, title = {Ability of biofilm production and molecular analysis of spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.}, journal = {BMC research notes}, volume = {13}, number = {1}, pages = {19}, pmid = {31910883}, issn = {1756-0500}, mesh = {Biofilms/*growth & development ; Drug Resistance, Microbial/genetics ; *Genes, Bacterial ; Hospitals ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/isolation & purification/*physiology ; Microbial Sensitivity Tests ; }, abstract = {OBJECTIVE: This study aimed to evaluate the phenotypic and genotypic characterization of biofilm formation and spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.

RESULT: This cross-sectional study was performed on 146 Staphylococcus aureus isolates from hospitalized patients in Isfahan Province Hospitals. MRSA isolates were confirmed using disk diffusion test with oxacillin disk and amplification of mecA gene by PCR assays. Ability of biofilm production was evaluated targeting the icaA and icaD genes. Of 146 Staphylococcus aureus isolates, 24 (16.4%) carried mecA genes and identified as MRSA strains. Strong ability of biofilm production was seen among 76.02% (111/146) S. aureus isolates and 87.5% (21/24) MRSA strains, respectively. Also, 75.0% (18/24) MRSA isolates carried icaA and icaD was not detected in these strains. Analysis of spa gene showed 70.83% (17/24) MRSA strains were spa positive. From which 14 and 3 strains identified with one band (150, 270, 300, 360, 400 bp) and two bands (150-300 bp), respectively. According to data obtained, the prevalence of MRSA isolates from Isfahan Province Hospitals is relatively high and a remarkable percentage of them show strong power in biofilm production. Also analysis of spa gene showed a fairly large diversity among MRSA strains.}, } @article {pmid31907602, year = {2020}, author = {Chen, G and Song, W and Ying, X}, title = {Horizontal Gene Transfer of Short-Chain Dehydrogenase Coding Genes Contribute to the Biofilm Formation and Pathogenicity on Mycobacterium grossiae sp. nov. PB739[T] (=DSM 104744[T]).}, journal = {Current microbiology}, volume = {77}, number = {4}, pages = {528-533}, pmid = {31907602}, issn = {1432-0991}, support = {2016F10025//Science and technology department of Zhejiang Province/ ; }, mesh = {Aged ; Base Composition ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; *Gene Transfer, Horizontal ; Genome, Bacterial ; Genomics ; Humans ; Male ; Mycobacterium/enzymology/*genetics/*pathogenicity ; Mycobacterium Infections/microbiology ; Oxidoreductases/*genetics ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Virulence ; }, abstract = {Mycobacterium grossiae sp. nov. of type strain PB739[T] is a Gram-positive acid-alcohol-fast rod-shaped bacterium, which was recently isolated from a 76-year-old male who suffered from a 1-year history of hemoptysis. This strain was described as novel species in Mycobacterium genus. In this study, its genome was completely sequenced by PacBio technology, analyzed, and compared with other selected complete genome sequences of Mycobacterium to elucidate the distinct pathogenic features of the strain. The genomic analysis revealed that the genome of PB739[T] consists of one circular DNA chromosome of 5,637,923 bp with a GC content of 70.48% and one plasmid of 43,679 bp with a GC content of 66.24%. The entire genome contains 5434 predicted coding genes, 48 tRNAs, and 6 rRNA genes. Genome and comparative genomics against M. grossiae SCH identified three tandem short-chain dehydrogenase (SDR) genes which only exist in PB739[T]. These three tandem SDR genes locate in a Genomic island which was identified by Island Viewer. These SDR genes were predicted to be horizontally transferred from a Streptomyces ancestor based on phylogeny. Analysis of the mutant ΔSDR confirmed the relationship between these tandem genes with biofilm and pathogenicity. This report will provide us with an extended understanding of M. grossiae at the genomic level and would be helpful for understanding the evolution of Mycobacterium genus.}, } @article {pmid31906541, year = {2020}, author = {Shokeen, B and Park, J and Duong, E and Rambhia, S and Paul, M and Weinberg, A and Shi, W and Lux, R}, title = {Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation.}, journal = {Microorganisms}, volume = {8}, number = {1}, pages = {}, pmid = {31906541}, issn = {2076-2607}, support = {R01DE018276/GF/NIH HHS/United States ; R01DE021108/NH/NIH HHS/United States ; }, abstract = {: RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacterium nucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcus gordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S. gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.}, } @article {pmid31906465, year = {2020}, author = {Pompilio, A and Savini, V and Fiscarelli, E and Gherardi, G and Di Bonaventura, G}, title = {Clonal Diversity, Biofilm Formation, and Antimicrobial Resistance among Stenotrophomonas maltophilia Strains from Cystic Fibrosis and Non-Cystic Fibrosis Patients.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {31906465}, issn = {2079-6382}, support = {Fondo Ricerca di Ateneo, anno 2017//Università degli Studi G. d'Annunzio Chieti - Pescara/ ; }, abstract = {The intrinsic antibiotic resistance of Stenotrophomonas maltophilia, along with its ability to form biofilm both on abiotic surfaces and host tissues, dramatically affects the efficacy of the antibiotic therapy. In this work, 85 S. maltophilia strains isolated in several hospital of central Italy and from several clinical settings were evaluated for their genetic relatedness (by pulsed-field gel electrophoresis, PFGE), biofilm formation (by microtiter plate assay), and planktonic antibiotic resistance (by Kirby-Bauer disk diffusion technique). The S. maltophilia population showed a high genetic heterogeneity: 64 different PFGE types were identified, equally distributed in cystic fibrosis (CF) and non-CF strains, and some consisted of multiple strains. Most of the strains (88.2%) were able to form biofilm, although non-CF strains were significantly more efficient than CF strains. CF strains produced lower biofilm amounts than non-CF strains, both those from respiratory tracts and blood. Non-CF PFGE types 3 and 27 consisted of strong-producers only. Cotrimoxazole and levofloxacin were the most effective antibiotics, being active respectively against 81.2% and 72.9% of strains. CF strains were significantly more resistant to piperacillin/tazobactam compared to non-CF strains (90% versus 53.3%), regardless of sample type. Among respiratory strains, cotrimoxazole was more active against non-CF than CF strains (susceptibility rates: 86.7% versus 75%). The multidrug resistant phenotype was significantly more prevalent in CF than non-CF strains (90% versus 66.7%). Overall, the multidrug-resistance level was negatively associated with efficiency in biofilm formation. Our results showed, for the first time, that in S. maltophilia both classical planktonic drug resistance and the ability of biofilm formation might favor its dissemination in the hospital setting. Biofilm formation might in fact act as a survival mechanism for susceptible bacteria, suggesting that clinical isolates should be routinely assayed for biofilm formation in diagnostic laboratories.}, } @article {pmid31905828, year = {2019}, author = {Ishchuk, OP and Sterner, O and Ellervik, U and Manner, S}, title = {Simple Carbohydrate Derivatives Diminish the Formation of Biofilm of the Pathogenic Yeast Candida albicans.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {31905828}, issn = {2079-6382}, support = {--//Stiftelsen Lars Hiertas Minne/ ; --//Magnus Bergvalls Stiftelse/ ; --//Lunds Universitet/ ; --//The Sten K. Johnson Foundation/ ; --//Kungliga Fysiografiska Sällskapet i Lund/ ; }, abstract = {The opportunistic human fungal pathogen Candida albicans relies on cell morphological transitions to develop biofilm and invade the host. In the current study, we developed new regulatory molecules, which inhibit the morphological transition of C. albicans from yeast-form cells to cells forming hyphae. These compounds, benzyl α-l-fucopyranoside and benzyl β-d-xylopyranoside, inhibit the hyphae formation and adhesion of C. albicans to a polystyrene surface, resulting in a reduced biofilm formation. The addition of cAMP to cells treated with α-l-fucopyranoside restored the yeast-hyphae switch and the biofilm level to that of the untreated control. In the β-d-xylopyranoside treated cells, the biofilm level was only partially restored by the addition of cAMP, and these cells remained mainly as yeast-form cells.}, } @article {pmid31905318, year = {2020}, author = {de Sousa, CA and Taborda, MBB and Momesso, GAC and Rocha, EP and Dos Santos, PH and Santiago-Júnior, JF and Assunção, WG}, title = {Materials Sealing Preventing Biofilm Formation in Implant/Abutment Joints: Which Is the Most Effective? A Systematic Review and Meta-Analysis.}, journal = {The Journal of oral implantology}, volume = {46}, number = {2}, pages = {163-171}, doi = {10.1563/aaid-joi-D-19-00121}, pmid = {31905318}, issn = {0160-6972}, mesh = {Biofilms ; Dental Abutments ; *Dental Implant-Abutment Design ; *Dental Implants ; Dental Prosthesis, Implant-Supported ; }, abstract = {The purpose of this systematic review was to evaluate the literature available for materials exhibiting the best efficacy in preventing biofilm formation in the interior of implants. We searched PubMed/MEDLINE, Scopus, and Cochrane databases. This review is registered with the PROSPERO database and followed the suitability of the PRISMA protocol. The initial search resulted in 326 articles from the databases. After they were read, 8 articles remained, and the inclusion and exclusion criteria were applied. Six of these 8 articles were classified as in vitro and 2 were classified as in situ. The regions of the implants evaluated ranged from the interface of the pieces to the occlusal upper access of the abutment. The implant connections evaluated the Morse taper, external connection, and internal connection. Meta-analysis of the quantitative data was performed at a significance level of .05. Cotton exhibited poor control of infiltration, even in combination with other materials. Isolated gutta-percha (GP) and polytetrafluoroethylene (PTFE) tape with composite resin (CR) or GP performed better as physical barriers. The best results for chemical barriers were observed by the application of 1% chlorhexidine gluconate (CG) gel, thymol varnish, and the deposition of Ag films onto the surface. The applied meta-analysis did not show a significant difference in comparison between the different types of implant connections (P > .05). The application of CG and thymol varnish antimicrobials was effective in preventing biofilm formation and easy clinical execution; these could be used in combination with CR, GP, and PTFE.}, } @article {pmid31904552, year = {2020}, author = {Ghorbanzadeh, A and Bahador, A and Sarraf, P and Ayar, R and Fekrazad, R and Asefi, S}, title = {Ex vivo comparison of antibacterial efficacy of conventional chemomechanical debridement alone and in combination with light-activated disinfection and laser irradiation against Enterococcus faecalis biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {29}, number = {}, pages = {101648}, doi = {10.1016/j.pdpdt.2019.101648}, pmid = {31904552}, issn = {1873-1597}, mesh = {Biofilms/drug effects/radiation effects ; Colony Count, Microbial ; *Debridement ; Dental Pulp Cavity/*microbiology ; Disinfection/*methods ; Enterococcus faecalis/*drug effects/*radiation effects ; Humans ; In Vitro Techniques ; Indocyanine Green/administration & dosage/pharmacology ; *Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/pharmacology ; Sodium Hypochlorite/administration & dosage/pharmacology ; }, abstract = {BACKGROUND AND OBJECTIVES: Intracanal disinfection plays an important role in endodontic treatment success. Enterococcus faecalis (E. faecalis) is a resistant microorganism responsible for endodontic infections. We aimed to assess the bactericidal effects of three disinfection methods on E. faecalis biofilm.

MATERIALS AND METHODS: Fifty-five freshly extracted single-rooted human teeth were evaluated. A barbed broach was used to extract the pulp tissue. No further root canal preparation was performed. Specimens were sterilized with gamma radiation, and inoculated with E. faecalis suspension. They were then incubated for 4 days and 4 weeks. Biofilm formation was confirmed using a scanning electron microscope (SEM). The teeth were randomly assigned to three subgroups (n = 7) to assess the antimicrobial efficacy of the following three disinfection methods against immature (4-day) and mature (4-week) biofilms: the conventional chemomechanical debridement (CCMD), CCMD + light-activated disinfection (LAD; 810 nm, 0.3 W, 120 J/cm[2]) with indocyanine Green (EmunDo) as photosensitizer and CCMD + diode laser irradiation (810 nm, 2 W). The teeth were then longitudinally split into two halves and the colony count was reported as colony forming units (CFUs) to assess bacterial viability after each disinfection protocol.

RESULTS: None of the disinfection methods could completely remove the biofilm. CCMD + LAD caused the highest and CCMD + diode laser caused the lowest reduction in biofilm. Antibacterial efficacy was significantly lower against the mature (4-week) biofilm compared with immature (4-day) biofilm in all groups (P < 0.05).

CONCLUSION: All three disinfection methods were effective for partial elimination of E. faecalis biofilm. But CCMD + LAD was significantly more efficacious in decreasing both mature and immature biofilms.}, } @article {pmid31904447, year = {2020}, author = {Ponce-Angulo, DG and Bautista-Hernández, LA and Calvillo-Medina, RP and Castro-Tecorral, FI and Aparicio-Ozores, G and López-Villegas, EO and Ribas-Aparicio, RM and Bautista-de Lucio, VM}, title = {Microscopic characterization of biofilm in mixed keratitis in a novel murine model.}, journal = {Microbial pathogenesis}, volume = {140}, number = {}, pages = {103953}, doi = {10.1016/j.micpath.2019.103953}, pmid = {31904447}, issn = {1096-1208}, mesh = {Animals ; *Biofilms ; Coinfection/microbiology ; Cornea/microbiology ; Disease Models, Animal ; Female ; Fusarium/*physiology ; Humans ; Immunocompromised Host ; Keratitis/immunology/*microbiology ; Mice ; Mice, Inbred BALB C ; Staphylococcus aureus/*physiology ; }, abstract = {PURPOSE: To report the characterization and analysis of the biofilm formation in mixed keratitis induced by the coinfection of Staphylococcus aureus and Fusarium falciforme in a novel murine model.

METHODS: Clinical ocular microbial isolates and female BALB/c mice were used to develop the murine model. Immunosuppression was achieved with cyclophosphamide and methylprednisolone. A corneoscleral lesion was performed with a micro-pocket technique. Mice received an inoculum with a concentration of 1 × 10[5] conidia of F. falciforme and S. aureus with 1 × 10[5] UFC/ml. Mice were sacrificed at 72 h after induction of infection, the right eye was enucleated and preserved in 10% formaldehyde to perform the PAS staining. In addition, cuts were obtained for the labeling with the fluorophores propidium iodide and Calcofluor White, and other eye cuts were processed to transmission microscopy.

RESULTS: F. falciforme and S. aureus were able to developed mono and mixed biofilm in vitro. Keratitis of F. falciforme, S. aureus and mixed, were established at immunosuppressed mice. Clinical symptoms were observed at murine cornea. Histological analysis by special stains identified bacterial, fungal and mixed biofilm structures at epithelial and stromal level. Extracellular matrix was observed surrounded clusters of bacterial, fungi and mixed by fluorescence and transmission electronic microscopy.

CONCLUSION: This study provides direct evidence of the establishment and formation of mixed biofilm in vitro, as well as in vivo on the corneal surface of mice in an experimentally induced S. aureus and F. falciforme mixed keratitis infection.}, } @article {pmid31903886, year = {2020}, author = {Kheiri, F and Kermanshahi, RK and Feizabadi, MM}, title = {The Inhibitory Effects of Lactobacillus Supernatants and Their Metabolites on the Growth and Biofilm Formation of Klebsiella pneumoniae.}, journal = {Infectious disorders drug targets}, volume = {20}, number = {6}, pages = {902-912}, doi = {10.2174/1871526520666200106122632}, pmid = {31903886}, issn = {2212-3989}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms ; Humans ; Klebsiella Infections/drug therapy ; *Klebsiella pneumoniae ; *Lactobacillus ; Microbial Sensitivity Tests ; *Urinary Tract Infections/drug therapy ; beta-Lactamases ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is a common cause of hospital-acquired infections, including urinary tract infection (UTI). Biofilm formation makes the K. pneumoniae infection more complicated and carrying extended-spectrum beta-lactamases (ESBLs) genes, it limits antibiotic choices for treatment. Lactobacillus strains are known as natural protective barriers against UTIs.

OBJECTIVES: This is a small in-vitro study aimed to determine the effect of probiotic Lactobacillus strains and some types of their metabolites on the growth and biofilm of UTI isolates and reference strain of Klebsiella pneumoniae.

METHODS: The efficacy of Lactobacillus supernatants and antibiotics in the prevention and elimination of K. pneumoniae biofilms was determined using a quantitative adherence assay. A rapid colorimetric microplate bioassay was applied for the detection of survived bacterial cells after treatment with antibacterial agents. Biofilm phenotypes were studied by scanning electron microscopy (SEM).

RESULTS: The results showed that seven out of eight ESBL producing uropathogenic K. pneumoniae isolates in this study were able to produce biofilm. Lactobacillus supernatants at 1:1 to 1:16 dilutions, had more than 95% biofilm-inhibitory and biofilm-killing properties on a strong biofilm producer isolate. Supra-MIC levels of antibiotics had a much lower anti-biofilm effect than Lactobacillus supernatant and left considerable alive biofilm cells.

CONCLUSIONS: Although antibiotic resistance increases in biofilm forms of Klebsiella pneumoniae, Lactobacillus supernatants have strong antibiofilm efficacy even in lower concentrations of MIC. Biofilm formation decreases considerably in the presence of Lactobacillus supernatants. Hydrogen peroxide is an effective product against growth and biofilm formation of Klebsiella pneumoniae.}, } @article {pmid31902639, year = {2020}, author = {Leyva-Díaz, JC and Monteoliva-García, A and Martín-Pascual, J and Munio, MM and García-Mesa, JJ and Poyatos, JM}, title = {Moving bed biofilm reactor as an alternative wastewater treatment process for nutrient removal and recovery in the circular economy model.}, journal = {Bioresource technology}, volume = {299}, number = {}, pages = {122631}, doi = {10.1016/j.biortech.2019.122631}, pmid = {31902639}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Nutrients ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Over the last years, an increasing concern has emerged regarding the eco-friendly management of wastewater. Apart from the role of wastewater treatment plants (WWTPs) for wastewater and sewage sludge treatment, the increasing need of the recovery of the resources contained in wastewater, such as nutrients and water, should be highlighted. This would allow for transforming a wastewater treatment plant (WWTP) into a sustainable technological system. The objective of this review is to propose a moving bed biofilm reactor (MBBR) as a novel technology that contributes to the circularity of the wastewater treatment sector according to the principles of circular economy. In this regard, this paper aims to consider the MBBR process as the initial step for water reuse, and nutrient removal and recovery, within the circular economy model.}, } @article {pmid31902502, year = {2020}, author = {Aper, D and Frömbling, J and Bağcıoğlu, M and Ehling-Schulz, M and Hennig-Pauka, I}, title = {Comparison of metabolic adaptation and biofilm formation of Actinobacillus pleuropneumoniae field isolates from the upper and lower respiratory tract of swine with respiratory disease.}, journal = {Veterinary microbiology}, volume = {240}, number = {}, pages = {108532}, doi = {10.1016/j.vetmic.2019.108532}, pmid = {31902502}, issn = {1873-2542}, mesh = {Actinobacillus Infections/microbiology/*veterinary ; Actinobacillus pleuropneumoniae/drug effects/growth & development/*metabolism ; *Adaptation, Physiological ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Bronchi/microbiology ; Lung/microbiology/pathology ; Microbial Sensitivity Tests ; Palatine Tonsil/microbiology ; Pleuropneumonia/microbiology/*veterinary ; Pneumonia, Bacterial/microbiology/*veterinary ; Respiratory Tract Diseases/microbiology/*veterinary ; Swine/microbiology ; Swine Diseases/microbiology ; }, abstract = {Most outbreaks of disease due to infection with Actinobacillus (A.) pleuropneumoniae are caused by pigs already pre-colonised in tonsillar tissue, where the pathogen is protected from exposure to antibiotic substances administered for treatment. As it has been shown recently under experimental conditions, A. pleuropneumoniae displays host tissue-specific metabolic adaptation. In this study, pairs of A. pleuropneumoniae field isolates were recovered from lung as well as from tonsillar and nasal tissue from 20 pigs suffering from acute clinical signs of pleuropneumonia and showing characteristic pathological lung alterations. Metabolic adaptation to the porcine lower and upper respiratory tract of 32 A. pleuropneumoniae serotype 2 field isolates was examined using Fourier transform infrared (FTIR) spectroscopy as a high resolution metabolic fingerprinting method. All strains showed metabolic adaptations to organ tissue reflected by hierarchical cluster analysis of FTIR spectra similar to those previously observed under experimental conditions. Notably, differences in antimicrobial resistance patterns and minimal inhibitory concentrations of isolates from different tissues in the same animal, but not in biofilm production capability in a microtiter plate assay were found. Overall, biofilm formation was observed for 71 % of the isolates, confirming that A. pleuropneumoniae field isolates are generally able to form biofilms, although rather in a serotype-specific than in an organ-specific manner. A. pleuropneumoniae serotype 6 isolates formed significantly more biofilm than the other serotypes. Furthermore, biofilm production was negatively correlated to the lung lesion scores and tonsillar isolates tended to be more susceptible to antimicrobial substances with high bioavailability than lung isolates.}, } @article {pmid31902330, year = {2020}, author = {Liu, Y and Zhang, J and Ji, Y}, title = {Environmental factors modulate biofilm formation by Staphylococcus aureus.}, journal = {Science progress}, volume = {103}, number = {1}, pages = {36850419898659}, doi = {10.1177/0036850419898659}, pmid = {31902330}, issn = {2047-7163}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms ; *Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; *Staphylococcus aureus/genetics ; }, abstract = {Biofilm formation on indwelling medical devices represents an exclusive evasion mechanism for many pathogenic bacteria to establish chronic infections. Staphylococcus aureus is one of the major bacterial pathogens that are able to induce both animal and human infections. The continued emergence of multiple drug-resistant S. aureus, especially methicillin-resistant S. aureus, is problematic due to limited treatment options. Biofilm formation by S. aureus complicates the treatment of methicillin-resistant S. aureus infections. Therefore, elucidating the mechanisms of biofilm formation in this pathogen is important for the development of alternative therapeutic strategies. Various environmental and genetic factors contribute to biofilm formation. In this review, we address the environmental factors and discuss how they affect biofilm formation by S. aureus.}, } @article {pmid31901662, year = {2020}, author = {Shah, T and Munsif, F and D'amato, R and Nie, L}, title = {Lead toxicity induced phytotoxic impacts on rapeseed and clover can be lowered by biofilm forming lead tolerant bacteria.}, journal = {Chemosphere}, volume = {246}, number = {}, pages = {125766}, doi = {10.1016/j.chemosphere.2019.125766}, pmid = {31901662}, issn = {1879-1298}, mesh = {Bacteria/drug effects ; *Biodegradation, Environmental ; Biofilms/*growth & development ; Brassica napus/microbiology/physiology ; Brassica rapa ; Environmental Pollution ; Lead/*toxicity ; Medicago ; Metals, Heavy/pharmacology ; Plant Roots/growth & development ; Soil ; Soil Pollutants/analysis/*toxicity ; Trifolium/microbiology/physiology ; }, abstract = {Lead (Pb[+2]) is a heavy metal and one of the main environmental pollutant, toxic to plants, animals and humans. Present study was conducted to evaluate ten plant growth promoting bacteria strains (B1-10) for biofilm production and their effect on growth indices, physiology, yield, antioxidant profile and lead uptake in rapeseed (Brassica napus) and clover (Trifolium repens) in lead polluted soil under nutrient broth medium and pot condition. Three pre-characterized biofilm forming lead tolerant growth promoting strains (B3: Pseudomonas fluorescens), B6: Pseudomonas putida and (B8: Bacillus safensis) were used to inoculate rapeseed and clover growing in the soil polluted with different levels (400, 800 and 1200 mg kg[-1]) of Pb arranged in completely randomized design with factorial arrangement. Results from screening experiment exhibited that more biofilm was produced by B3, B6 and B8 under highest level of lead contamination (1200 mg kg[-1]). Further, lead contamination decreased rapeseed and clover growth, physiology and yield at all levels of lead stress. But biofilm forming lead tolerant growth promoting bacteria application in lead contaminated soil enhanced rapeseed and clover growth, physiology, yield, antioxidant profile, proline and decreased malanodialdehyde content (which was decreased by different strains application under lead stress) of rapeseed and clover over no inoculation. Inoculation with all strains also increased the lead uptake in roots, shoots and decreased lead uptake in seeds of rapeseed and clover than plants in lead stress without inoculation.}, } @article {pmid31899382, year = {2020}, author = {Ghorbanzadeh, R and Assadian, H and Chiniforush, N and Parker, S and Pourakbari, B and Ehsani, B and Alikhani, MY and Bahador, A}, title = {Modulation of virulence in Enterococcus faecalis cells surviving antimicrobial photodynamic inactivation with reduced graphene oxide-curcumin: An ex vivo biofilm model.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {29}, number = {}, pages = {101643}, doi = {10.1016/j.pdpdt.2019.101643}, pmid = {31899382}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Curcumin/*pharmacology ; Enterococcus faecalis/*drug effects/pathogenicity ; Graphite/*pharmacology ; In Vitro Techniques ; Microbial Sensitivity Tests ; Photochemotherapy/*methods ; Virulence/*drug effects ; }, abstract = {BACKGROUND: Enterococcus faecalis, as a major microorganism in persistent/secondary infections of endodontically treated teeth, is less likely to be eliminated during endodontic therapy. In this study, the effect of root canal disinfection and anti-virulence activities of photodynamic inactivation (PDI) of E. faecalis utilizing reduced graphene oxide-curcumin (rGO-Cur) as a photosensitizing agent following irradiation with light-emitting diode (LED), as well as intracellular ROS production were evaluated on ex vivo biofilms of E. faecalis in comparison with sodium hypochlorite (NaOCl) as the traditional endodontic irrigation solution.

MATERIALS AND METHODS: After formulation and confirmation of synthesized rGO-Cur using scanning electron microscopy (SEM), Fourier transformation infrared (FT-IR), UV-Vis spectra, dynamic light scattering (DLS), and Zeta potential, the minimum biofilm inhibitory concentrations (MBICs) and in vitro anti-biofilm activity of rGO-Cur, light-emitting diode (LED) at the wavelength of 435 ± 20 nm, and rGO-Cur-PDI were determined against 4-week-old pre-formed biofilms of E. faecalis. After preparation of ex vivo biofilm model in root canals, the ex-vivo anti-biofilm potential of rGO-Cur, LED, and rGO-Cur-PDI against E. faecalis were analyzed using the XTT assay and scanning electron microscopy (SEM) in comparison with NaOCl. The effects of sub-MBIC of rGO-Cur and NaOCl, sub-lethal dose of LED, and sub-significant inhibitory (SSI) potential of rGO-Cur-PDI for E. faecalis biofilms on virulence genes (efa, esp, gel, and fsr) expression of E. faecalis were analyzed using real-time polymerase chain reaction (qRT-PCR) assay. Intracellular reactive oxygen species (ROS) level was measured in rGO-Cur-PDI-treated bacterial cells compared to control cells with 2',7'-dichlorfluorescein-diacetate (DCFH-DA) fluorescent probe.

RESULTS: The FTIR, DLS, Zeta potential, SEM, and UV-Vis spectra analysis indicated the successful synthesis of rGO-Cur. The MBIC of rGO-Cur was 250 μg/ml, which inhibited the growth ofE. faecalis. LED showed insignificant anti-biofilm activity against E. faecalis even after treating for a long irradiation time (300 s). According to checkerboard assay, the MBIC value of rGO-Cur-PDI was reduced noticeably compared to the individual MBIC values of rGO-Cur and LED for E. faecalis. The expression levels of efa, esp, gel, and fsr genes in pre-formed E. faecalis biofilms were markedly reduced after rGO-Cur, rGO-Cur-PDI, and NaOCl treatment in comparison with the control group. Conversely, LED revealed no significant change in the expression of the virulence genes. The intracellular ROS assay showed a significant increase (8.3-fold) in rGO-Cur-PDI when compared to the control.

CONCLUSION: Our data support that rGO-Cur-PDI showed dual inhibitory effects on biofilm formation ability and virulence activity of E. faecalis with potential clinical applications for infection control in endodontics.}, } @article {pmid31899376, year = {2020}, author = {Abdulrahman, H and Misba, L and Ahmad, S and Khan, AU}, title = {Curcumin induced photodynamic therapy mediated suppression of quorum sensing pathway of Pseudomonas aeruginosa: An approach to inhibit biofilm in vitro.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {30}, number = {}, pages = {101645}, doi = {10.1016/j.pdpdt.2019.101645}, pmid = {31899376}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms ; *Curcumin/pharmacology ; *Photochemotherapy/methods ; Photosensitizing Agents/pharmacology ; Pseudomonas aeruginosa ; Quorum Sensing ; }, abstract = {OBJECTIVE: The objective of this study was to inhibit the Pseudomonas aeruginosa biofilm through curcumin-mediated antimicrobial photodynamic therapy (A-PDT).

BACKGROUND: The mechanism behind A-PDT mediated photoinactivation depend upon reactive oxygen species (ROS) production, like singlet oxygen and free radicals.

METHODS: To evaluate the antibacterial efficacy of curcumin induced A-PDT on P. aeruginosa by colony forming unit (CFU) while antibiofilm action was determined by the use of crystal violet, XTT, congored binding assay and confocal laser scanning microscope (CLSM).

RESULTS: We found that curcumin with 10 J/cm[2] of light reduces P. aeruginosa biofilm more efficiently than without light. Extracellular polymeric substances (EPS) production was also reduced by approx 94 % with 10 J/cm[2] of light dose. CLSM images showed that the thickness of biofilms were reduced from >30 μm to <5 μm after treatment with curcumin followed by 10 J/cm[2] of light irradiation. Curcumin showed better bacteriostatic activity than bactericidal activity. Singlet oxygen is primarily responsible for photodamage and cytotoxic reactions caused by curcumin-mediated APDT. Genes involved in quorum sensing (QS) pathway was also found to be inhibited after APDT. Curcumin with 5 J/cm[2] light inhibits QS genes and on increasing light dose i.e10 J/cm[2], we found a drastic reduction in gene expression.

CONCLUSION: We conclude that the curcumin mediated A-PDT inhibits biofilm formation ofP. aeruginosa through QS pathway by the action of singlet oxygen generation which in turn reduced EPS of the biofilm.}, } @article {pmid31899281, year = {2020}, author = {Schwarzer, S and James, GA and Goeres, D and Bjarnsholt, T and Vickery, K and Percival, SL and Stoodley, P and Schultz, G and Jensen, SO and Malone, M}, title = {The efficacy of topical agents used in wounds for managing chronic biofilm infections: A systematic review.}, journal = {The Journal of infection}, volume = {80}, number = {3}, pages = {261-270}, doi = {10.1016/j.jinf.2019.12.017}, pmid = {31899281}, issn = {1532-2742}, mesh = {Animals ; *Biofilms ; Humans ; *Wound Infection/drug therapy ; }, abstract = {OBJECTIVES: Clinicians have increasingly adopted the widespread use of topical agents to manage chronic wound infections, despite limited data on their effectiveness in vivo. This study sought to evaluate the evidence for commonly employed topical agents used in wounds for the purpose of treating chronic infections caused by biofilm.

METHOD: We included in vitro, animal and human in vivo studies where topical agents were tested for their efficacy against biofilms, for use in wound care. For human studies, we only included those which utilised appropriate identification techniques for visualising and confirming the presence of biofilms.

RESULT: A total of 640 articles were identified, with 43 included after meeting eligibility. In vitro testing accounted for 90% (n = 39) of all included studies, five studies using animal models and three human in vivo studies. Sixteen different laboratory models were utilised, with the most frequent being the minimum biofilm eradication concentration (MBEC™) / well plate assay (38%, n = 15 of 39). A total of 44 commercially available topical agents were grouped into twelve categories with the most commonly tested agents being silver, iodine and polyhexamethylene biguanide (PHMB). In vitro results on efficacy demonstrated iodine as having the highest mean log10 reductions of all agents (4.81, ±3.14).

CONCLUSION: There is large disparity in the translation of laboratory studies to researchers undertaking human trials relating to the effectiveness of commercially available topical agents. There is insufficient human in vivo evidence to definitively recommend any commercially available topical agent over another for the treatment of chronic wound biofilms. The heterogeneity identified between study designs (in vitro to in vivo) further limits the generalisability of results.}, } @article {pmid31898890, year = {2020}, author = {Soldano, A and Yao, H and Chandler, JR and Rivera, M}, title = {Inhibiting Iron Mobilization from Bacterioferritin in Pseudomonas aeruginosa Impairs Biofilm Formation Irrespective of Environmental Iron Availability.}, journal = {ACS infectious diseases}, volume = {6}, number = {3}, pages = {447-458}, pmid = {31898890}, issn = {2373-8227}, support = {R01 AI125529/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Crystallography, X-Ray ; Cytochrome b Group/*metabolism ; Ferredoxins/metabolism ; Ferritins/*metabolism ; Homeostasis ; Iron/*metabolism ; Models, Molecular ; Pseudomonas aeruginosa/*metabolism ; }, abstract = {Although iron is essential for bacteria, the nutrient presents problems of toxicity and solubility. Bacteria circumvent these problems with the aid of iron storage proteins where Fe[3+] is deposited and, when necessary, mobilized as Fe[2+] for metabolic requirements. In Pseudomonas aeruginosa, Fe[3+] is compartmentalized in bacterioferritin (BfrB), and its mobilization as Fe[2+] requires specific binding of a ferredoxin (Bfd) to reduce the stored Fe[3+]. Blocking the BfrB-Bfd complex leads to irreversible iron accumulation in BfrB and cytosolic iron deprivation. Consequently, given the intracellular iron sufficiency requirement for biofilm development, we hypothesized that blocking the BfrB-Bfd interaction in P. aeruginosa would impair biofilm development. Our results show that planktonic and biofilm-embedded cells where the BfrB-Bfd complex is blocked exhibit cytosolic iron deficiency, and poorly developed biofilms, even in iron-sufficient culture conditions. These results underscore inhibition of the BfrB-Bfd complex as a rational target to dysregulate iron homeostasis and possibly control biofilms.}, } @article {pmid31897991, year = {2020}, author = {Aydin, ME and Beduk, F and Aydin, S and Koyuncu, S and Genuit, G and Bahadir, M}, title = {Development of biofilm collectors as passive samplers in sewerage systems-a novel wastewater monitoring method.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {8}, pages = {8199-8209}, pmid = {31897991}, issn = {1614-7499}, mesh = {Biofilms ; Environmental Monitoring ; Germany ; *Metals, Heavy/chemistry ; Turkey ; *Wastewater/analysis/chemistry ; }, abstract = {In this study, a novel wastewater sampling method based on biofilm collection on a multi-armed polyethylene strips (so called "Octopus") is proposed. The implementation of this method is a step forward to prevent illegal industrial discharges into sewerage systems and receiving water bodies. Prior applications of biofilm collection were performed in Bielefeld, Germany, in 1994. The success of the method encouraged other municipalities to apply this method for monitoring indirect discharges into sewerage systems. Municipality of Konya, Turkey, started to use the method in 2013. Continuous monitoring has been performed for the determination of regulated heavy metals: chromium (Cr), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), mercury (Hg) and cadmium (Cd). Unauthorized discharges of Cr, Zn and Ni were identified in Konya by performing sewerage slime tests through biofilm analyses. 2686 mg/kg d.m. Cr, 3949 mg/kg d.m. Zn and 3300 mg/kg d.m. Ni were highest values determined for biofilm samples taken from monitoring sites. In this paper, the principles of the method will be introduced, and findings from the wastewater of Konya City will be given in comparison with findings from Bielefeld, Germany. Conducted results reveal high (and likely illegal) heavy metal discharges into the sewerage system in Konya. The continuous monitoring of sewerage systems with biofilm collectors is an effective and efficient method for point source control of wastewater pollutants.}, } @article {pmid31896640, year = {2020}, author = {Boukerb, AM and Simon, M and Pernet, E and Jouault, A and Portier, E and Persyn, E and Bouffartigues, E and Bazire, A and Chevalier, S and Feuilloley, MGJ and Lesouhaitier, O and Caillon, J and Dufour, A}, title = {Draft Genome Sequences of Four Pseudomonas aeruginosa Clinical Strains with Various Biofilm Phenotypes.}, journal = {Microbiology resource announcements}, volume = {9}, number = {1}, pages = {}, pmid = {31896640}, issn = {2576-098X}, abstract = {Biofilms produced by Pseudomonas aeruginosa present a serious threat to cystic fibrosis patients. Here, we report the draft genome sequences of four cystic fibrosis isolates displaying various mucoid and biofilm phenotypes. The estimated average genome size was about 6,255,986 ± 50,202 bp with a mean G+C content of 66.52 ± 0.06%.}, } @article {pmid31896623, year = {2020}, author = {Tram, G and Klare, WP and Cain, JA and Mourad, B and Cordwell, SJ and Korolik, V and Day, CJ}, title = {RNA Sequencing Data Sets Identifying Differentially Expressed Transcripts during Campylobacter jejuni Biofilm Formation.}, journal = {Microbiology resource announcements}, volume = {9}, number = {1}, pages = {}, pmid = {31896623}, issn = {2576-098X}, abstract = {Campylobacter jejuni is a foodborne pathogen and an important contributor to gastroenteritis in humans. C. jejuni readily forms biofilms which may play a role in the transmission of the pathogen from animals to humans. Herein, we present RNA sequencing data investigating differential gene expression in biofilm and planktonic C. jejuni These data provide insight into pathways which may be important to biofilm formation in this organism.}, } @article {pmid31896192, year = {2020}, author = {Li, W and Tan, Q and Zhou, W and Chen, J and Li, Y and Wang, F and Zhang, J}, title = {Impact of substrate material and chlorine/chloramine on the composition and function of a young biofilm microbial community as revealed by high-throughput 16S rRNA sequencing.}, journal = {Chemosphere}, volume = {242}, number = {}, pages = {125310}, doi = {10.1016/j.chemosphere.2019.125310}, pmid = {31896192}, issn = {1879-1298}, mesh = {Biofilms/*drug effects ; Chloramines/*pharmacology ; Chlorine/*pharmacology ; Construction Materials/microbiology ; Disinfectants/*pharmacology ; Disinfection/methods ; Drinking Water/chemistry/*microbiology ; Iron ; Microbiota/*drug effects/genetics ; RNA, Ribosomal, 16S/genetics ; Stainless Steel ; Water Microbiology/standards ; }, abstract = {The bacterial composition of biofilms in drinking water distribution systems is significantly impacted by the disinfection regime and substrate material. However, studies that have addressed the changes in the biofilm community during the early stage of formation (less than 10 weeks) were not yet adequate. Here, we explore the effects of the substrate materials (cast iron, stainless steel, copper, polyvinyl chloride, and high density polyethylene) and different disinfectants (chlorine and chloramine) on the community composition and function of young biofilm by using 16S rDNA sequencing. The results showed that Alphaproteobacteria (39.14%-80.87%) and Actinobacteria (5.90%-40.03%) were the dominant classes in chlorine-disinfection samples, while Alphaproteobacteria (17.46%-74.18%) and Betaproteobacteria (3.79%-68.50%) became dominant in a chloraminated group. The infrequently discussed genus Phreatobacter became predominant in the chlorinated samples, but it was inhibited by chloramine and copper ions. The key driver of the community composition was indicated as different disinfectants according to principle coordination analysis (PCoA) and Permutational multivariate analysis of variance (Adonis test), and the bacterial community changed significantly over time. Communities of biofilms grown on cast iron showed a great distance from the other materials according to Bray-Curtis dissimilarity, and they had a unique dominant genus, Dechloromonas. A metagenomics prediction based on 16S rDNA was used to detect the functional pathways of antibiotic biosynthesis and beta-lactam resistance, and it revealed that several pathways were significantly different in terms of their chlorinated and chloraminated groups.}, } @article {pmid31895639, year = {2020}, author = {Da Cunda, P and Iribarnegaray, V and Papa-Ezdra, R and Bado, I and González, MJ and Zunino, P and Vignoli, R and Scavone, P}, title = {Characterization of the Different Stages of Biofilm Formation and Antibiotic Susceptibility in a Clinical Acinetobacter baumannii Strain.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {6}, pages = {569-575}, doi = {10.1089/mdr.2019.0145}, pmid = {31895639}, issn = {1931-8448}, mesh = {Acinetobacter baumannii/*drug effects/*growth & development ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Cross Infection/microbiology ; Drug Resistance, Multiple, Bacterial/drug effects ; Genes, Bacterial ; Humans ; Microbial Sensitivity Tests ; Plankton/drug effects/growth & development ; }, abstract = {Acinetobacter baumannii is a relevant opportunistic pathogen, and one of the main microorganisms responsible for outbreaks in nosocomial infections worldwide. Its pathogenicity is mainly due to its resistance to multiple antibiotics and to its ability to form biofilms on abiotic surfaces. The objective of this study was to characterize the biofilm formation cycle of A. baumannii isolated from a patient in a hospital and compare its antibiotic resistance with the planktonic cells. To study biofilm formation, the classical microtiter assay was used, with crystal violet staining and optical density reading to classify the type of biofilm. Also, the effect of gentamicin and colistin on bacterial biofilm was studied with an extra step of antibiotic addition. For the characterization of the different biofilm formation stages, the strain was grown on a coverslip, and the stain was made with a mixture of fluorophores markers to visualize the biofilm with a confocal laser microscope. It was possible to differentiate the A. baumannii biofilm formation stages. Through these observations, it was possible to estimate the time elapsed between each stage. As the strain was susceptible to colistin and gentamicin, both antibiotics were evaluated after the biofilm was formed. Neither antibiotics showed an effect on the eradication of A. baumannii biofilm.}, } @article {pmid31895006, year = {2020}, author = {Gu, L and Chen, Q and Guo, A and Liu, W and Ruan, Y and Zhang, X and Nou, X}, title = {Differential Effects of Growth Medium Salinity on Biofilm Formation of Two Salmonella enterica Strains.}, journal = {Journal of food protection}, volume = {83}, number = {2}, pages = {196-203}, doi = {10.4315/0362-028X.JFP-19-418}, pmid = {31895006}, issn = {1944-9097}, abstract = {ABSTRACT: Salmonella enterica is a prominent foodborne pathogen, including diverse serotypes that are prolific biofilm formers. Its ability to form biofilm can be affected by multiple environmental factors. In this study, the effect of salinity on biofilm formation by S. enterica was evaluated by using two recently isolated strains of Salmonella serotypes Enteritidis and Newport. Although supplementing the growth medium with a low concentration (0.5 to 2%) of sodium chloride (NaCl) slightly enhanced biofilm formation for the strain S. enterica serovar Enteritidis 110, it sharply reduced or abolished biofilm formation by the strain S. enterica serovar Newport 193. This differential effect of salinity on S. enterica strains of different serotypes was poorly correlated with inhibition of planktonic growth but strongly correlated with cell motility. Examining genes known to affect biofilm formation showed that the expression of adrA, csgD, and fliC, which encode proteins required for surface adhesion and cell motility, was significantly downregulated with salinity increase in Salmonella Newport 193 but not in Salmonella Enteritidis 110. Therefore, it is plausible that the differential effect of salinity on biofilm formation by Salmonella Enteritidis 110 and Salmonella Newport 193 resulted from the differential regulation to genes required for cell adherence and motility.}, } @article {pmid31894064, year = {2019}, author = {Mirza, R and Azeem, M and Qaisar, U}, title = {Influence of Peganum harmala peptides on the transcriptional activity of biofilm related genes in sensitive and resistant strains of Pseudomonas aeruginosa and Staphylococcus aureus.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {32}, number = {5(Supplementary)}, pages = {2341-2345}, pmid = {31894064}, issn = {1011-601X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Fimbriae Proteins/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; *Peganum ; Peptides/*pharmacology ; Plankton/drug effects ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Staphylococcus aureus/*drug effects/genetics/physiology ; }, abstract = {Microbial biofilms have gathered interest in recent years as they have become the major cause of nosocomial infections. The abuse and misuse of antibiotics have created a selective pressure that results in widespread formation of resistant bacterial strains and a need to devise novel plant based antimicrobials. In this study, antimicrobial peptides were isolated from Peganum harmala and their effect was examined on biofilm related colonization genes of Pseudomonas aeruginosa and Staphylococcus aureus isolated from burn and surgical wounds. Results showed that in P. aeruginosa isolated from burn wound, the expression of flagellar gene (flgK), pilin gene (pilA) and fimbriae gene (cupA1) was significantly down-regulated indicating that Peganum harmala antimicrobial peptides (PhAMP) damage locomotors of planktonic cells by affecting the gene expression while in resistant biofilm cells, the expression of flgK, cupA1 and polysaccharide synthesis gene (pslA) was enhanced in the presence of PhAMP. In P. aeruginosa isolated from surgical wounds which was more sensitive; the expression of flgK, pilA, cupA1 and pslA was significantly down-regulated in biofilms and planktonic cells in the presence of PhAMP thus disrupting locomotors of planktonic as well as biofilm cells. In S. aureus isolated from burn wounds; the expression of capsular polysaccharide synthesis gene (CPS5) and inter cellular adhesion gene (icaA) was significantly up-regulated in biofilms as well as in planktonic cells in response to PhAMP stress showing resistance mechanism. Thus these genes can be used as efficient resistance markers for bacterial pathogens against antimicrobial agents.}, } @article {pmid31893017, year = {2020}, author = {Dubar, M and Zaffino, ML and Remen, T and Thilly, N and Cunat, L and Machouart, MC and Bisson, C}, title = {Protozoans in subgingival biofilm: clinical and bacterial associated factors and impact of scaling and root planing treatment.}, journal = {Journal of oral microbiology}, volume = {12}, number = {1}, pages = {1693222}, pmid = {31893017}, issn = {2000-2297}, abstract = {Objective: In patients with periodontitis, identification of protozoans and evaluation of some bacteria and clinical parameters associated and assessment of scaling and root planing (SRP) impact on their detection. Methods: Before and after SRP, subgingival microbiota was collected in two pathological and one healthy site from 30 periodontitis patients. One healthy site from 30 control patients was also sampled. The usual clinical periodontal parameters were recorded; microbial detection was determined by PCR hybridization system for bacteria and qPCR for protozoans. Results: In periodontitis group, Trichomonas tenax and two subtypes of Entamoeba gingivalis (ST1 and a variant ST2) were detected in respectively 33.3%, 70% and 18.3% of pathological samples, and in 6.7%, 10% and 3.3% healthy samples. In control group, ST1 alone was found in 3.3% of individuals. ST1 was associated with Gingival Index, Clinical Attachment Level (p ≤ 0.03) and with the total bacterial count (p = 0.02). T. tenax alone was associated with P. gingivalis, T. denticola and E. nodatum (p ≤ 0,02). After therapy, only T. tenax detection decreased significantly (p = 0.004) and no association between the protozoan elimination and improvement of pathological sites was found. Conclusions: Protozoans were associated with some clinical parameters and/or periodontopathogens in patients with periodontitis.}, } @article {pmid31892683, year = {2019}, author = {Andonissamy, L and Karthigeyan, S and Ali, SA and Felix, JW}, title = {Effect of Chemical Denture Disinfectants and Tree Extracts on Biofilm-forming Staphylococcus aureus and Viridans Streptococcus Species Isolated from Complete Denture.}, journal = {The journal of contemporary dental practice}, volume = {20}, number = {11}, pages = {1307-1314}, pmid = {31892683}, issn = {1526-3711}, mesh = {Biofilms ; Denture, Complete ; *Disinfectants ; Disinfection ; Humans ; Plant Extracts ; Sodium Hypochlorite ; Staphylococcus aureus ; Trees ; }, abstract = {AIMS: The present study aims at recording the antibacterial efficacy of various disinfectants used at different time periods against Staphylococcus aureus and viridans streptococcal species of bacteria isolated from complete dentures.

MATERIALS AND METHODS: Fifty complete denture patients were selected for the study and swabs were collected from their complete denture surfaces. The isolated bacteria were subjected to six experimental groups which includes four groups of chemical denture disinfectants and two tree extracts groups. Isolation of the bacteria S. aureus and viridians streptococcal species was done by means of selective media and confirmed by means of biochemical tests. The bacteria were subjected to biofilm assays. The biofilm-forming bacteria with optical density (O.D.) values of more than 1.5 were selected for the study. About 150 acrylic specimens were fabricated and were contaminated by the 2 isolated bacteria mentioned above. The contaminated samples were disinfected by immersion for 10, 20, and 30 minutes in six disinfectants, namely: (1) 1% sodium hypochlorite, (2) 2% chlorhexidine, (3) 2% glutaraldehyde, (4) 3.8% sodium perborate, (5) 2% aalam extract, and (6) 2% neem extract.

RESULTS: ANOVA test was performed for both S. aureus and viridans streptococcal species with regard to various synthetic and tree extracts as well as time duration of disinfection. F values for disinfection vs S. aureus is 205.4 (p < 0.001) and the relevant Scheffe post hoc test values is in the following order: 3 < 1, 4 < 6, 2 < 5. F values for disinfection vs viridans streptococcal species is 364.7 (p < 0.001) and the relevant Scheffe post hoc test values is in the following order: 3 < 4 < 1, 6, 2 < 5.

CONCLUSION: For biofilm-forming S. aureus, 2% glutaraldehyde showed best antibacterial efficacy which was followed by 1% sodium hypochlorite and 3.8% sodium perborate. When it comes to biofilm-forming viridans streptococcal species, 2% glutaraldehyde showed best antibacterial efficacy. Next to 2% glutaraldehyde, 3.8% sodium perborate exhibited good disinfection potential.

CLINICAL SIGNIFICANCE: Complete denture patients have a plethora of microorganisms habitating their complete dentures. Some bacteria are capable of causing systemic illness such as aspiration pneumonia and endocarditis. Hence, constant removal and disinfection of biofilms from the denture surface is vital to the local and systemic wellness of the patient. The most common bacteria capable of causing pneumonia and endocarditis that are isolated from complete dentures include S. aureus and viridans streptococcal species. The present study evaluates antibacterial efficacy of different disinfection agents especially against these biofilm-forming bacteria for different time periods. How to cite this article: Andonissamy L, Karthigeyan S, Ali SA, et al. Effect of Chemical Denture Disinfectants and Tree Extracts on Biofilm-forming Staphylococcus aureus and Viridans Streptococcus Species Isolated from Complete Denture. J Contemp Dent Pract 2019;20(11):1307-1314.}, } @article {pmid32027606, year = {2018}, author = {Triveni, AG and Suresh Kumar, M and Manjunath, C and Shivannavar, CT and Gaddad, SM}, title = {Biofilm formation by clinically isolated Staphylococcus Aureus from India.}, journal = {Journal of infection in developing countries}, volume = {12}, number = {12}, pages = {1062-1066}, doi = {10.3855/jidc.10671}, pmid = {32027606}, issn = {1972-2680}, mesh = {Bacteriological Techniques/*methods ; *Biofilms ; Humans ; India ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*isolation & purification/pathogenicity/*physiology ; }, abstract = {INTRODUCTION: Staphylococcal biofilms are prominent cause for acute and chronic infection both in hospital and community settings across the world. Current study explores biofilm formation by Staphylococcus aureus isolates from clinical samples by different methods.

METHODOLOGY: Standard techniques used for the characterization of S.aureus. Qualitative and quantitative biofilm formation was assessed by Congo red Agar, Tube and Microtiter plate methods.

RESULTS: A total of 188 clinical isolates of S.aureus were screened for biofilm formation and 72 (38.29%) of them were found to be biofilm producers, 34 (18.08%) strong, 38 (20.21%) moderate. The remaining 116 (61.7%) were weak/ non biofilm producers. Maximum biofilm formers were recorded in pus samples (39.06%), followed by isolates from blood (38.23%) and urine (34.61%). Statistical analysis for the formation of biofilm indicated that Microtiter plate method is the most sensitive and specific method for screening biofilm production.

CONCLUSIONS: Biofilm formation is one of the influential virulence factor in staphylococcal pathogenesis and persistence. Microtiter plate and Congo red agar remain as reliable methods for the qualitative and quantitative estimation of biofilm formation. Monitoring of biofilm formation in various etiological agents will help in determining the severity of infection.}, } @article {pmid32012126, year = {2018}, author = {Soltani, S and Arshadi, M and Getso, MI and Aminharati, F and Mahmoudi, M and Pourmand, MR}, title = {Prevalence of virulence genes and their association with biofilm formation in VRE faecium isolates from Ahvaz, Iran.}, journal = {Journal of infection in developing countries}, volume = {12}, number = {11}, pages = {970-977}, doi = {10.3855/jidc.10078}, pmid = {32012126}, issn = {1972-2680}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Cross Infection/etiology ; Enterococcus faecium/genetics ; Humans ; Iran ; Microbial Sensitivity Tests ; Vancomycin Resistance/*genetics ; Vancomycin-Resistant Enterococci/isolation & purification ; Virulence/*drug effects ; Virulence Factors/genetics ; }, abstract = {INTRODUCTION: Vancomycin-resistant Enterococcus faecium (VREfm) is a common cause of nosocomial infections. Biofilm formation is an important factor in recurrence of infections, facilitating transfer of genetic elements, leading to treatment failures. The aim of this study was to investigate the virulence genes in biofilm producing isolates and to determine possible association between biofilm formation and the presence of these genes; also to determine association between antibiotic susceptibility patterns of VREfm isolates and their biofilm formation ability.

METHODOLOGY: A total of 57 isolates of VREfm were recovered from different sources of hospitals under Ahvaz University, Iran. The isolates were examined by conventional microbiological methods and molecular test using PCR. The antibiotic susceptibility patterns of the isolates were determined by disk-diffusion and E-test. The biofilm formation ability of the isolates was investigated by Modified Congo red agar and microtiter plate techniques. The presence of virulence genes was examined using Multiplex-PCR method.

RESULTS: Out of 57 VREfm isolates, 63.15% of isolates were biofilm producers. The frequency of biofilm producing isolates from clinical specimens, colonized patients and environmental sources were 78.26%, 60%, and 42.85%, respectively. The prevalence of acm, esp and hyl genes among biofilm producing isolates was 86.10%, 55.56% and 52.77%, respectively. There was statistically significant association between esp gene and biofilm formation among isolates from the clinical specimens.

CONCLUSION: Clinical isolates producing biofilms showed a positive association with the presence of the esp. Our study further suggests that the link between virulence genes and biofilms is affected by the environmental context.}, } @article {pmid32254404, year = {2018}, author = {Bing, W and Sun, H and Wang, F and Song, Y and Ren, J}, title = {Hydrogen-producing hyperthermophilic bacteria synthesized size-controllable fine gold nanoparticles with excellence for eradicating biofilm and antibacterial applications.}, journal = {Journal of materials chemistry. B}, volume = {6}, number = {28}, pages = {4602-4609}, doi = {10.1039/c8tb00549d}, pmid = {32254404}, issn = {2050-7518}, abstract = {Herein, we employed the hydrogen-producing hyperthermophilic bacterial strain Caldicellulosiruptor changbaiensis for preparing uniform and size-tunable gold nanoparticles (AuNPs). Compared with the commonly used chemically synthesized nanoparticles, the biological synthesis of nanoparticles appears to be a suitable process since it has a low manufacturing cost of scalability, good biocompatibility, and better nanoparticles stabilization. The produced AuNPs possessed a unique property, whereby the smallest AuNPs exhibited the highest peroxidase activity over a broad pH range, even at neutral pH, which was quite different from the commonly chemical-synthesized ones. Also, when the size of AuNPs increased, the peroxidase activity of B-AuNPs at neutral pH decreased. Owing to the excellent antibacterial capability of ROS, the AuNPs exhibited striking antibacterial properties against both Gram-positive and Gram-negative bacteria, and moreover, the AuNPs showed excellent ability to disperse bacterial biofilms both in vitro and in vivo. Our studies indicate that living bacterial cells, as a biosynthesizer, can synthesize size-controllable AuNPs with improved bioactivity. This work may promote the design and synthesis of other types of metal nanoparticles with defined properties for future applications.}, } @article {pmid32161861, year = {2018}, author = {Schlafer, S and Garcia, J and Meyer, RL and Vaeth, M and Neuhaus, KW}, title = {Effect of DNase Treatment on Adhesion and Early Biofilm Formation of Enterococcus Faecalis.}, journal = {European endodontic journal}, volume = {3}, number = {2}, pages = {82-86}, pmid = {32161861}, issn = {2548-0839}, abstract = {OBJECTIVE: Extracellular DNA (eDNA) has been shown to be important for biofilm stability of the endodontic pathogen Enterococcus faecalis. In this study, we hypothesized that treatment with DNase prevents adhesion and disperses young E. faecalis biofilms in 96-well plates and root canals of extracted teeth.

METHODS: E. faecalis eDNA in 96-well plates was visualized with TOTO-1®. The effect of DNase treatment was assessed in 96-well plates and in extracted single-rooted premolars (n=37) using a two-phase crossover design. E. faecalis was treated with DNase (50 Kunitz/mL) or heat-inactivated DNase for 1 h during adhesion or after 24 h of biofilm formation. In 96-well plates, adhering cells were quantified using confocal microscopy and digital image analysis. In root canals, the number of adhering cells was determined in dentine samples based on colony forming unit counts. Data from the 96-well plate were analyzed using one-tailed t-tests, and data from extracted teeth were analyzed using mixed-effect Poisson regressions.

RESULTS: eDNA was present in wells colonized by E. faecalis after 1 h of adhesion and 24 h of biofilm formation; it was removed by DNase treatment, as evidenced by TOTO®-1 staining. DNase treatment reduced the area covered by cells in 96-well plates after 1 h (P<0.05), but not after 24 h (P=0.96). No significant differences in the number of adhering cells were observed in extracted teeth after 1 (P=0.14) and 24 h (P=0.98).

CONCLUSION: DNase treatment does not disperse endodontic E. faecalis biofilms. The sole use of DNase as an anti-biofilm agent in root canal treatments is not recommendable.}, } @article {pmid32254504, year = {2018}, author = {Li, X and Wu, B and Chen, H and Nan, K and Jin, Y and Sun, L and Wang, B}, title = {Recent developments in smart antibacterial surfaces to inhibit biofilm formation and bacterial infections.}, journal = {Journal of materials chemistry. B}, volume = {6}, number = {26}, pages = {4274-4292}, doi = {10.1039/c8tb01245h}, pmid = {32254504}, issn = {2050-7518}, abstract = {Since their development over 70 years, antibiotics are still the most effective strategy to treat bacterial biofilms and infections. However, the overuse of antibiotics in human healthcare and industrial applications has resulted in the development of serious antibiotic-resistant bacteria. Therefore, alternative ways to prevent bacteria attachment and biofilm formation are urgently needed. Recently, mediated biofilm formation processes and smart antibacterial surfaces have emerged as promising strategies to prevent and treat bacterial infections. This review discusses the recent progress in biofilm interference and smart antibacterial surfaces. Smart antibacterial and anti-biofilm surfaces should be responsive to the bacterial infection environment, switchable between various antibacterial functions and have a special bio-inspired structure and function. The major topics discussed are: (i) smart anti-biofilm surfaces via the prevention of biofilm formation or promoting mature biofilm dissolution, (ii) smart materials for reversible killing and/or release of bacteria, (iii) smart surfaces responsive to bacterial infection microenvironments or external stimuli and (iv) bio-inspired surfaces with antifouling and bactericidal properties.}, } @article {pmid31897448, year = {2018}, author = {Wilson, C and Brigham, B and Sandoval, J and Sabatka, D and Wilson, E and Sebest, C and Schofield, BJ and Holmes, AE and Sutlief, AL}, title = {The Quantitative Assessment of Pseudomonas aeruginosa (PA)14 Biofilm Surface Coverage on Slippery Liquid Infused Polymer Surfaces (SLIPS).}, journal = {International journal of nanotechnology in medicine & engineering}, volume = {3}, number = {3}, pages = {35-42}, pmid = {31897448}, issn = {2474-8811}, support = {P20 GM103427/GM/NIGMS NIH HHS/United States ; }, abstract = {Slippery, porous polymeric antimicrobial surfaces for biofilm attachment inhibition of the clinical strain Pseudomonas aeruginosa (PA14) have been prepared. Porous BMA-EDMA, characterized for its hydrophobic properties, was infused with a slippery liquid creating a hydrophobic liquid interface and characterized by water contact angle and SEM. A low shear force bioreactor was used to prepare biofilms on these antimicrobial surfaces. Biofilm attachment was studied using fluorescence microscopy coupled with image analysis in ImageJ. While the literature presents that these slippery polymers work well as antimicrobial surfaces for several strains of Pseudomonas aeruginosa, it has been found to be strain dependent. This report demonstrates that slippery surfaces do not work well for the strain PA14, and biofilm covered >3.5 times more area as compared to the control glass surfaces.}, } @article {pmid32254209, year = {2018}, author = {Wen, J and Yeh, CK and Sun, Y}, title = {Salivary polypeptide/hyaluronic acid multilayer coatings act as "fungal repellents" and prevent biofilm formation on biomaterials.}, journal = {Journal of materials chemistry. B}, volume = {6}, number = {10}, pages = {1452-1457}, pmid = {32254209}, issn = {2050-7518}, support = {R01 DE021084/DE/NIDCR NIH HHS/United States ; }, abstract = {Candida-associated denture stomatitis (CADS) is a common, recurring clinical complication in denture wearers that can lead to serious oral and systemic health problems. Current management strategies are not satisfactory due to their short-acting and ineffective therapeutic effects. Here, we describe a new fungal biofilm controlling strategy using the polyelectrolyte layer-by-layer (LBL) self-assembly technology on denture materials. Conventional poly(methyl methacrylate) (PMMA) denture material discs were functionalized with negatively charged poly(methacrylic acid) (PMAA) via plasma-initiated surface grafting, followed by repetitive alternating coating with the salivary antimicrobial polypeptide histatin 5 (H-5; cationic polymer) and hyaluronic acid (HA; anionic polymer). On the other hand, the H-5/HA LBL coatings (i.e., the outermost layer was H-5) inhibited fungal attachment/adhesion, significantly reduced fungal biofilm formation, and showed synergistic effects with the antifungal drug miconazole. LBL surface hydrophilicity was not the key mechanism in controlling Candida biofilm formation. The current approach demonstrates the utility of a new design principle for fabricating anticandidal denture materials, as well as potentially other related medical devices, for controlling fungal biofilm formation and combating insidious infections.}, } @article {pmid32254487, year = {2018}, author = {Zhou, Z and Hu, F and Hu, S and Kong, M and Feng, C and Liu, Y and Cheng, X and Ji, Q and Chen, X}, title = {pH-Activated nanoparticles with targeting for the treatment of oral plaque biofilm.}, journal = {Journal of materials chemistry. B}, volume = {6}, number = {4}, pages = {586-592}, doi = {10.1039/c7tb02682j}, pmid = {32254487}, issn = {2050-7518}, abstract = {Oral plaque biofilms are highly resilient microbial assemblies that are challenging to eradicate. Herein, we describe the synthesis and study of pH-positive, doxycycline (DOX)-loaded nanocarriers to combat pathogenic biofilms. The mixed shell-core nanoparticles consisted of quaternary ammonium chitosan (TMC) as a positively charged section, which targeted nanoparticles to negatively charged biofilm surfaces. In addition liposomes were used as a DOX loading tool to eradicate the multidrug-resistant biofilm. In a drug release test, DOX release was pH-dependent with t1/2 = 0.75 h and 2.3 h for release at pH 4.5 and 6.8, respectively. Furthermore, TMC-Lip-DOX NPs could adhere to the biofilm and efficiently remove the biofilm from the hydroxyapatite (HA) surface. Furthermore, TMC-Lip-DOX NPs had biocomaptible properties and were non-toxic to MC3T3-E1 cells. This constitutes a highly effective pathway to control oral plaque biofilms and has a good potential use for dental biofilm therapies.}, } @article {pmid32264505, year = {2017}, author = {Cochis, A and Ferraris, S and Sorrentino, R and Azzimonti, B and Novara, C and Geobaldo, F and Truffa Giachet, F and Vineis, C and Varesano, A and Sayed Abdelgeliel, A and Spriano, S and Rimondini, L}, title = {Silver-doped keratin nanofibers preserve a titanium surface from biofilm contamination and favor soft-tissue healing.}, journal = {Journal of materials chemistry. B}, volume = {5}, number = {42}, pages = {8366-8377}, doi = {10.1039/c7tb01965c}, pmid = {32264505}, issn = {2050-7518}, abstract = {Peri-implantitis is a severe condition affecting the success of transmucosal dental implants: tissue healing is severely limited by the inflammatory processes that come about to control homeostasis in the surrounding tissues. The main cause of peri-implantitis is bacterial biofilm infection; gingival fibroblasts play a pivotal role in regulating the inflammatory cascades. A new technology aimed at preventing bacterial colonization of titanium (Ti) implants, and enhancing the spread of gingival fibroblasts, is presented. Using electro-spinning, mirror-polished Ti disks were uniformly coated with keratin fibers obtained from discarded wool via sulfitolysis. The keratin-coated surfaces were then doped with silver (Ag) to introduce antibacterial properties, using different concentrations of silver nitrate as a precursor (0.01, 0.05 and 0.1 M). The resulting specimens were characterized in terms of morphology and chemical composition by FESEM, FTIR and XPS, revealing silver concentrations between 1.7 and 1.9%. Silver release into the medium was evaluated in the presence of cells (α-MEM) or bacteria (LB) by ICP; release was 0.2-1.4 mg l[-1] for α-MEM, and 10-40 mg l[-1] for LB. The antibacterial properties of the Ag-doped specimens were tested against a multidrug-resistant Staphylococcus aureus biofilm through morphology (FESEM) and metabolic assay (XTT); reduction in viability was significant (p < 0.05; >80% reduction within 72 h). Lastly, the cytocompatibility of the specimens was confirmed using human primary gingival fibroblasts, whose viability, spread and matrix deposition were found to be comparable to those of untreated Ti polished controls (p > 0.05). Thus, Ag surface enrichment was effective in reducing viability and maturation of S. aureus biofilm, without compromising human cell viability. Moreover, cell spread was found to be very sensitive to keratin fiber stimulation. The strategy thus appears to be very promising to introduce surface features in line with the main requirements for transmucosal dental implants.}, } @article {pmid32624830, year = {2017}, author = {Mulansky, S and Saballus, M and Friedrichs, J and Bley, T and Boschke, E}, title = {A novel protocol to prepare cell probes for the quantification of microbial adhesion and biofilm initiation on structured bioinspired surfaces using AFM for single-cell force spectroscopy: Dedicated to Prof. em. Dr. Dr. H.C. Karl Schügerl on the occasion of his 90th birthday.}, journal = {Engineering in life sciences}, volume = {17}, number = {8}, pages = {833-840}, pmid = {32624830}, issn = {1618-0240}, abstract = {We present a novel protocol that uses single-cell force spectroscopy to characterize the bacteria-to-surface interactions involved in early steps of biofilm formation. Bacteria are immobilized as a monolayer by electrostatic interactions on a polyethylenimine-coated silica bead, and the Escherichia coli-bead complex is then glued on a tipless cantilever. We validated our new protocol by comparing to earlier published methods using single bacteria, but in contrast to these, which carry out bacterial attachment to the bead after fixation to the cantilever, our protocol results in more reliable production of usable cell probes. Measurements of interactions of E. coli with bio-inspired surfaces by single-cell force spectroscopy yielded comparable detachment forces to those found with the previous methods.}, } @article {pmid32566898, year = {2016}, author = {Zan, R and Tunç, T and Hubbezoğlu, İ and Sümer, Z}, title = {Apical extrusion of intracanal biofilm using ProTaper Gold, WaveOne Gold,Twisted File Adaptive, OneShape New Generation and K3XF.}, journal = {European endodontic journal}, volume = {1}, number = {1}, pages = {1-6}, pmid = {32566898}, issn = {2548-0839}, abstract = {OBJECTIVE: To evaluate the bacterial extrusion during instrumentation with different nickel titanium (NiTi) engine-driven instruments.

METHODS: Ninety extracted single-canal human mandibular incisor teeth were inoculated with Enterococcus faecalis to obtain biofilm formation and were randomly divided to 6 groups (n=15). One group served as the control and was not instrumented; the other groups were prepared with ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold (WOG; Dentsply Maillefer), Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), One Shape New Generation (OSNG; MicroMega, Besancon, France), and K3XF (SybronEndo) instruments. Bacteria extruded beyond the apical foramen were quantified in colony-forming units per milliliter. The number of colony-forming units in the remaining biofilm was determined for each sample. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey post-hoc tests.

RESULTS: All NiTi instruments resulted in different quantities of bacterial extrusion. The TFA group caused most bacterial extrusion (P<0.05). The PTG and WOG groups caused less bacterial extrusion than the OSNG and K3XF groups (P<0.05), but there was no statistically significant difference between the PTG and WOG groups (P>0.05).

CONCLUSION: PTG and WOG are preferable system in terms of successful endodontic treatments. The amount of bacterial extrusion is associated with the metallurgy and design of the instrument used.}, } @article {pmid32263603, year = {2016}, author = {Malek, I and Schaber, CF and Heinlein, T and Schneider, JJ and Gorb, SN and Schmitz, RA}, title = {Vertically aligned multi walled carbon nanotubes prevent biofilm formation of medically relevant bacteria.}, journal = {Journal of materials chemistry. B}, volume = {4}, number = {31}, pages = {5228-5235}, doi = {10.1039/c6tb00942e}, pmid = {32263603}, issn = {2050-7518}, abstract = {A significant part of human infections is frequently associated with the establishment of biofilms by (opportunistic) pathogens. Due to the increasing number of untreatable biofilms, there is a rising need to develop novel and effective strategies to prevent biofilm formation on surfaces in medical as well as in technical areas. Bacterial initial attachment and adhesion to surfaces followed by biofilm formation is highly influenced by the physical properties of the surfaces. Consequently, changing these properties or applying different nanostructures is an attractive approach to prevent biofilm formation. Here we report on the effect(s) of surface grown and anchored vertically aligned multi walled carbon nanotubes (MWCNT), which have been made wettable by immersion through a graded ethanol series, on biofilm formation of Klebsiella oxytoca, Pseudomonas aeruginosa, and Staphylococcus epidermidis. We evaluated the biofilm formation under continuous flow conditions by confocal laser scanning microscopy and scanning electron microscopy, and demonstrated significant inhibition of biofilm formation of all the different pathogens by MWCNT of different lengths. Furthermore, the anti-adhesive effects of the MWCNT increased with their overall length. The application potential of our findings on surface grown and anchored vertically aligned MWCNT may represent a suitable contact mechanics based approach to prevent biofilm formation on medical devices or technical sensors operating in fluid environments.}, } @article {pmid32262317, year = {2015}, author = {Yin, P and Huang, GB and Tse, WH and Bao, YG and Denstedt, J and Zhang, J}, title = {Nanocomposited silicone hydrogels with a laser-assisted surface modification for inhibiting the growth of bacterial biofilm.}, journal = {Journal of materials chemistry. B}, volume = {3}, number = {16}, pages = {3234-3241}, doi = {10.1039/c4tb01871k}, pmid = {32262317}, issn = {2050-7518}, abstract = {Surface and interface modifications of synthetic silicone hydrogels used for wearable and implantable medical devices, e.g. catheters and contact lenses, are critical to overcome their poor mechanical properties and biofouling. In this paper, silica nanoparticles (SiO2 NPs) were incorporated within silicone hydrogels through photo-polymerization. As compared to the silicone hydrogel, the nanocomposited silicone hydrogel shows highly textured microstructures, increased swelling behaviour and improved stiffness. Meanwhile, a hydrophilic surface of silicone hydrogel is important to minimize protein fouling which forms a conditioning layer for the growth of bacterial biofilm. Here, we applied matrix-assisted pulsed laser evaporation (MAPLE) with a pulsed Nd:YAG laser at 532 nm to deposit polyethylene glycol (PEG) on the surface of the nanocomposited silicone hydrogels. The PEG deposited on the nanocomposited silicone hydrogels forms islands at the submicron-scale, which increase with increasing irradiation time (t). The protein adsorption on nanocomposited silicone hydrogel with PEG deposition decreases over 40 ± 2% when t = 2 h. Compared to the commercial silicone catheters, the nanocomposited silicone hydrogel with PEG deposition can reduce the growth of bacteria from 1.20 × 10[6] CFU cm[-2] to 3.69 × 10[5] CFU cm[-2]. In addition, the relative cell viabilities of NIH/3T3 mouse fibroblast cells treated using the nanocomposited silicone hydrogels coated with/without PEG were studied. No toxic effect is imposed on the cells. Consequently, the MAPLE process is a controllable, contamination-free technique to modify the surface of silicone hydrogels. We expect that the nanocomposited silicone hydrogels with appropriate surface treatment can be applied in various wearable and implantable medical devices.}, } @article {pmid32262406, year = {2015}, author = {Thomas, N and Dong, D and Richter, K and Ramezanpour, M and Vreugde, S and Thierry, B and Wormald, PJ and Prestidge, CA}, title = {Quatsomes for the treatment of Staphylococcus aureus biofilm.}, journal = {Journal of materials chemistry. B}, volume = {3}, number = {14}, pages = {2770-2777}, doi = {10.1039/c4tb01953a}, pmid = {32262406}, issn = {2050-7518}, abstract = {The anti-biofilm effect of drug delivery systems composed of the antiseptic quaternary ammonium compound cetylpyridinium chloride (CPC) and cholesterol was evaluated in Staphylococcus aureus biofilm. Self-assembly of CPC/cholesterol to approximately 100 nm CPC-quatsomes was successfully accomplished by a simple sonication/dispersion method over a broad concentration range from 0.5 to 10 mg ml[-1] CPC. CPC-quatsomes showed a dose-dependent anti-biofilm effect, killing >99% of biofilm-associated S. aureus from 5% mg ml[-1] after 10 minutes exposure. Cell toxicity studies with CPC-quatsomes in Nuli-1 cells revealed no adverse effects at all tested CPC concentrations. CPC-quatsomes, therefore, have a promising potential as novel drug delivery systems with "built-in" anti-biofilm activity.}, } @article {pmid31930157, year = {2015}, author = {Brown, L and Kessler, A and Casadevall, A}, title = {Vesicle Isolation from Bacillus subtilis Biofilm.}, journal = {Bio-protocol}, volume = {5}, number = {5}, pages = {}, pmid = {31930157}, issn = {2331-8325}, support = {R01 AI033142/AI/NIAID NIH HHS/United States ; R01 AI033774/AI/NIAID NIH HHS/United States ; R01 HL059842/HL/NHLBI NIH HHS/United States ; R01 AI052733/AI/NIAID NIH HHS/United States ; R37 AI033142/AI/NIAID NIH HHS/United States ; }, abstract = {Bacterial biofilms are associated clinically with many bacterial infections including those caused by bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus. In recent years, extracellular vesicles produced by bacteria have been isolated from biofilm communities. Vesicles have been described in depth and can encapsulate various virulence factors including toxins and immunomodulatory compounds. Vesicles may be important for virulence and survival by serving as a vehicle for the secretion and concentrated delivery of these molecules. Studying extracellular vesicles is an important step towards understanding biofilm formation, structure, and disruption with the ultimate goal of preventing or treating hospital infections caused by bacterial pathogens residing in biofilms. Here we describe the protocol for isolating vesicles from biofilm produced by Bacillus subtilis.}, } @article {pmid32264488, year = {2015}, author = {Pechook, S and Sudakov, K and Polishchuk, I and Ostrov, I and Zakin, V and Pokroy, B and Shemesh, M}, title = {Bioinspired passive anti-biofouling surfaces preventing biofilm formation.}, journal = {Journal of materials chemistry. B}, volume = {3}, number = {7}, pages = {1371-1378}, doi = {10.1039/c4tb01522c}, pmid = {32264488}, issn = {2050-7518}, abstract = {Biofilm formation enables bacteria to grow under unfavorable conditions, provides them with protection, and increases their resistance to antimicrobial agents. Once a biofilm has formed, it is difficult, and in some systems, impossible to treat. Strategies based on the release of biocidal agents have shown only transient efficiency. Herein, we present a novel bioinspired passive approach to the prevention of surface biofilm attachment by exploiting superhydrophobic surfaces formed via the self-assembly of paraffin or fluorinated wax crystals. Our surfaces show exceptional ability to inhibit biofilm formation of both Gram-positive Bacillus cereus and Gram-negative Pseudomonas aeruginosa over a 7 day period (up to 99.9% inhibition).}, } @article {pmid32261833, year = {2014}, author = {Duong, HTT and Adnan, NNM and Barraud, N and Basuki, JS and Kutty, SK and Jung, K and Kumar, N and Davis, TP and Boyer, C}, title = {Functional gold nanoparticles for the storage and controlled release of nitric oxide: applications in biofilm dispersal and intracellular delivery.}, journal = {Journal of materials chemistry. B}, volume = {2}, number = {31}, pages = {5003-5011}, doi = {10.1039/c4tb00632a}, pmid = {32261833}, issn = {2050-7518}, abstract = {Gold nanoparticles (size 10 nm) were designed to store and release nitric oxide (NO), by functionalizing their surfaces with functional polymers modified with NO-donor molecules. Firstly, block copolymer chains consisting of poly(oligoethylene glycol methyl ether methacrylate)-b-poly(vinyl benzyl chloride) (P(OEGMA)-b-PVBC)) were prepared using RAFT polymerization. The chloro-functional groups were then reacted with hexylamine, to introduce secondary amine groups to the copolymer chains. The block copolymers were then grafted onto the surface of gold nanoparticles, exploiting the end-group affinity for gold - attaining grafting densities of 0.6 chain per nm[2]. The secondary amine functional groups were then converted to N-diazeniumdiolate NO donor molecules via exposure to NO gas at high pressure (5 atm). The NO-bearing, gold nanoparticles were characterized using a range of techniques, including transmission electron microscopy, dynamic light scattering (DLS), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The nanoparticles displayed slow release of the nitric oxide in biological media. Proof of potential utility was then demonstrated in two different application areas: Pseudomonas aeruginosa biofilm dispersal and cancer cell cytotoxicity.}, } @article {pmid32261224, year = {2013}, author = {Eshed, M and Lellouche, J and Banin, E and Gedanken, A}, title = {MgF2 nanoparticle-coated teeth inhibit Streptococcus mutans biofilm formation on a tooth model.}, journal = {Journal of materials chemistry. B}, volume = {1}, number = {32}, pages = {3985-3991}, doi = {10.1039/c3tb20598c}, pmid = {32261224}, issn = {2050-7518}, abstract = {The formation of biofilms on tooth surfaces, called dental plaque, is a prerequisite for the development of both dental caries and periodontal disease. Streptococcus mutans plays an important role in the development of dental caries. Fluoride is routinely used to protect teeth against decay. In the current study, we examined whether we can use a sonochemical based method to coat artificial teeth with MgF2 nanoparticles (NPs). The results showed that the artificial tooth surface was homogenously and evenly covered with an MgF2 NP layer and successful in inhibiting S. mutans biofilm formation by over 60%. This antibiofilm activity was also present following incubation with saliva. The activity was dependent on the nano-crystalline characteristics of the material as fluoride ions could induce a similar reduction in biofilm formation. Taken together, our results indicate that the surface modification of artificial teeth with MgF2 NPs can be effective in preventing the S. mutans biofilm.}, } @article {pmid32481834, year = {2013}, author = {Rzhepishevska, O and Hakobyan, S and Ruhal, R and Gautrot, J and Barbero, D and Ramstedt, M}, title = {The surface charge of anti-bacterial coatings alters motility and biofilm architecture.}, journal = {Biomaterials science}, volume = {1}, number = {6}, pages = {589-602}, doi = {10.1039/c3bm00197k}, pmid = {32481834}, issn = {2047-4849}, abstract = {Bacterial biofilms affect many areas of human activity including food processing, transportation, public infrastructure, and most importantly healthcare. This study addresses the prevention of biofilms and shows that the surface charge of an abiotic substrate influences bacterial motility as well as the morphology and physiology of the biofilm. Grafting-from polymerisation was used to create polymer brush surfaces with different characteristics, and the development of Pseudomonas aeruginosa biofilms was followed using confocal microscopy. Interestingly, two types of biofilms developed on these surfaces: mushroom structures with high levels of cyclic diguanylate (c-di-GMP) were found on negatively charged poly (3-sulphopropylmethacrylate) (SPM) and zwitterionic poly (2-(methacryloyloxy)ethyl)dimethyl-3-sulphoproyl) ammonium hydroxide) (MEDSAH), while flat biofilms developed on glass, positively charged poly (2-(methacryloyloxy)-ethyl trimethyl ammonium chloride) (METAC), protein-repellent poly oligo(ethylene glycol methyl ether methacrylate) (POEGMA) and hydrophobic polymethylmethacrylate (PMMA). The results show that of all the surfaces studied, overall the negatively charged polymer brushes were most efficient in reducing bacterial adhesion and biofilm formation. However, the increased level of regulatory c-di-GMP in mushroom structures suggests that bacteria are capable of a quick physiological response when exposed to surfaces with varying physicochemical characteristics enabling some bacterial colonization also on negatively charged surfaces.}, } @article {pmid31891540, year = {2020}, author = {Yener, SB and Özsoy, ÖP}, title = {Quantitative analysis of biofilm formation on labial and lingual bracket surfaces.}, journal = {The Angle orthodontist}, volume = {90}, number = {1}, pages = {100-108}, pmid = {31891540}, issn = {1945-7103}, mesh = {*Biofilms ; Humans ; Lip ; Orthodontic Appliance Design ; *Orthodontic Brackets/microbiology ; *Orthodontic Wires/microbiology ; Tongue ; *Tooth ; Tooth Movement Techniques ; }, abstract = {OBJECTIVES: To evaluate and compare the biofilm formation between labial and lingual orthodontic brackets.

MATERIALS AND METHODS: Twenty patients with a mean age of 24 ± 8.8 who had received labial or lingual orthodontic treatment were enrolled in the study. Biofilm formation on 80 brackets was analyzed quantitatively with the Rutherford backscattering detection method. Five micrographs were obtained per bracket with views from the vestibule/lingual, mesial, distal, gingival, and occlusal aspects. Quantitative analysis was carried out with surface analysis software (ImageJ 1.48). Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests (α = 0.05).

RESULTS: Total biofilm formation was 41.56% (min 29.43% to max 48.76%) on lingual brackets and 26.52% (min 21.61% to max 32.71%) on labial brackets. Differences between the two groups were found to be significant. No difference was observed in intraoral location. The biofilm accumulation was mostly located on gingival, mesial, and distal surfaces for both groups.

CONCLUSIONS: The biofilm accumulation on lingual orthodontic therapy was found to be more than labial orthodontic therapy.}, } @article {pmid31891070, year = {2019}, author = {Lara, HH and Black, DM and Moon, C and Orr, E and Lopez, P and Alvarez, MM and Baghdasarian, G and Lopez-Ribot, J and Whetten, RL}, title = {Activating a Silver Lipoate Nanocluster with a Penicillin Backbone Induces a Synergistic Effect against S. aureus Biofilm.}, journal = {ACS omega}, volume = {4}, number = {26}, pages = {21914-21920}, pmid = {31891070}, issn = {2470-1343}, abstract = {Many antibiotic resistances to penicillin have been reported, making them obsolete against multiresistant bacteria. Because penicillins act by inhibiting cell wall production while silver particles disrupt the cell wall directly, a synergetic effect is anticipated when both modes of action are incorporated into a chimera cluster. To test this hypothesis, the lipoate ligands (LA) of a silver cluster (Ag29) of known composition (Ag29LA12)[[3-]] were covalently conjugated to 6-aminopenicillanic acid, a molecule with a β-lactam backbone. Indeed, the partially conjugated cluster inhibited an Staphylococcus aureus biofilm, in a dose-response manner, with a half-maximal inhibitory concentration IC50 of 2.3 μM, an improvement over 60 times relative to the unconjugated cluster (IC50 = 140 μM). An enhancement of several orders of magnitude over 6-APA alone (unconjugated) was calculated (IC50 = 10 000 μM). Cell wall damage is documented via scanning electron microscopy. A synergistic effect of the conjugate was calculated by the combination index method described by Chou-Talalay. This hybrid nanoantibiotic opens a new front against multidrug-resistant pathogens.}, } @article {pmid31890796, year = {2020}, author = {De Jesus, R and Dedeles, G}, title = {Data on quantitation of Bacillus cereus sensu lato biofilms by microtiter plate biofilm formation assay.}, journal = {Data in brief}, volume = {28}, number = {}, pages = {104951}, pmid = {31890796}, issn = {2352-3409}, abstract = {The microtiter plate biofilm formation assay is a method for the study of early biofilm formation on abiotic surfaces. It is a colorimetric technique that uses dyes, such as crystal violet, to stain attached biofilms and to quantify by using an absorbance microtiter plate reader. In this data, we evaluated the ability of 12 Bacillus cereus sensu lato isolated from soil and milk powder samples for their production of biofilms after a total of 48 hr incubation period in the 96-well microtiter plate. The biofilm production was induced by initially exposing them in diluted tryptic soy broth at its first 24 hr and then replacing with freshly prepared double strength broth for the next incubation period at 30 °C. The optical densities of the bacterial growth in the wells were read at the absorbance wavelength of 630 nm while the stained biofilms that solubilized in absolute ethanol were read at 570 nm. The biofilm measurements were calculated and the degree of biofilm production of each isolate was classified according to biofilm formation categories adapted from previous researchers. Therefore, the assay concluded the negative impact of B. cereus group by ability to form biofilms on abiotic surfaces, such as food contact surfaces in food production industries and the wide application of the current methods in research and industrial fields.}, } @article {pmid31890013, year = {2019}, author = {Nirwati, H and Sinanjung, K and Fahrunissa, F and Wijaya, F and Napitupulu, S and Hati, VP and Hakim, MS and Meliala, A and Aman, AT and Nuryastuti, T}, title = {Biofilm formation and antibiotic resistance of Klebsiella pneumoniae isolated from clinical samples in a tertiary care hospital, Klaten, Indonesia.}, journal = {BMC proceedings}, volume = {13}, number = {Suppl 11}, pages = {20}, pmid = {31890013}, issn = {1753-6561}, abstract = {BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) is a common cause of health-care associated infections (HAIs) and has high levels of antibiotic resistance. These bacteria are well-known for their ability to produce biofilm. The purpose of this study was to identify the antibiotic resistance pattern and biofilm-producing capacity of K. pneumoniae isolated from clinical samples in a tertiary care hospital in Klaten, Indonesia.

METHODS: K. pneumoniae was isolated from inpatients in Soeradji Tirtonegoro Hospital Klaten from June 2017 to May 2018. Identification of K. pneumoniae isolate was done by analyzing colony morphology, microscopic examination, and by performing biochemical testing. Testing of antibiotics susceptibility and biofilm-producing capacity used the Kirby-Bauer disk diffusion method and adherence quantitative assays, respectively.

RESULTS: A total of 167 (17.36%) K. pneumoniae isolates were isolated from 962 total clinical bacterial isolates during the study. Most of them were collected from patients aged more than 60 years old and were mainly obtained from respiratory specimens (51.50%). Most of K. pneumoniae isolates were extensively resistant to antibiotics. A more favorable profile was found only towards meropenem, amikacin, and piperacillin-tazobactam, showing 1.20%; 4.79% and 10.53% of resistance, respectively. The overall proportion of multidrug-resistant K. pneumoniae isolates was 54.49%. In addition, 148 (85.63%) isolates were biofilm producers, with 45 (26.95%) isolates as strong, 48 (28.74%) isolates as moderate, and 50 (29.94%) isolates as weak biofilm producers.

CONCLUSION: Most of the K. pneumoniae isolates demonstrated resistance to a wide range of antibiotics and are biofilm producers.}, } @article {pmid31890012, year = {2019}, author = {Krislee, A and Fadly, C and Nugrahaningsih, DAA and Nuryastuti, T and Nitbani, FO and Jumina, and Sholikhah, EN}, title = {The 1-monolaurin inhibit growth and eradicate the biofilm formed by clinical isolates of Staphylococcus epidermidis.}, journal = {BMC proceedings}, volume = {13}, number = {Suppl 11}, pages = {19}, pmid = {31890012}, issn = {1753-6561}, abstract = {BACKGROUND: Biofilm is one of the causes of antibiotic resistance. One of the biofilm-producing bacteria is Staphylococcus epidermidis which has been proven to infect long-term users of urinary catheters and implant devices. The 1-monolaurin compound has been known to have an antimicrobial effect. However, its effect on clinical isolates of S. epidermidis in producing biofilm has not been established. This study was conducted to investigate the effect of 1-monolaurin towards biofilm forming clinical isolates of S. epidermidis.

METHODS: The experiment used micro broth dilution technique which consists of test group (1-monolaurin), positive control group (rifampicin), solvent group, negative control group (clinical isolate of S. epidermidis), and media group (TSB media). The Minimal Inhibition Concentration (MIC) was determined by incubating bacteria added with 1-monolaurin (1000-1953 μg/mL) or rifampicin (250-0,488 μg/mL) for 24 h. The MIC was determined visually. After that, the incubated bacteria was cultured in TSA media to determine Minimal Bactericidal Concentration (MBC). The assessment of Biofilm inhibitory Concentration (BIC) and Biofilm Eradication Concentration (BEC) was conducted with the same way, the difference was BIC intervened directly with compound meanwhile BEC was incubated for 24 h in 37 °C before the intervention. Then, the specimen was reincubated to grow biofilm at the microplate, washed with PBS and stained with 1% of crystal violet. The optical density (OD) was measured at a wavelength of 595 nm. The percentage of BIC and BEC then were calculated, continued to probit analysis regression to determine the BIC50, BIC80, BEC50, and BEC80.

RESULTS: The MIC dan MBC of 1-monolaurin and rifampicin were > 1000 μg/mL, > 1000 μg/mL, ≤0.488 μg/mL, and 1.953 μg/mL respectively. BIC50 and BIC80 of 1-monolaurin and rifampicin were 26.669 μg/mL, 168.688 μg/mL, 0.079 μg/mL, and 0.974 μg/mL respectively. The BEC50 and BEC80 of 1-monolaurin and rifampicin were 322.504 μg/mL, 1338.681 μg/mL, 5.547 μg/mL, dan 17.910 μg/mL respectively.

CONCLUSION: The 1-monolaurin can inhibit growth and eradicate the biofilm formed by clinical isolates of S. epidermidis, however, it has neither inhibit nor kill planktonic cells of S. epidermidis.}, } @article {pmid31889815, year = {2020}, author = {Jasmine, S and A, T and Janarthanan, K and Krishnamoorthy, R and Alshatwi, AA}, title = {Antimicrobial and antibiofilm potential of injectable platelet rich fibrin-a second-generation platelet concentrate-against biofilm producing oral staphylococcus isolates.}, journal = {Saudi journal of biological sciences}, volume = {27}, number = {1}, pages = {41-46}, pmid = {31889815}, issn = {1319-562X}, abstract = {Injectable Platelet rich fibrin (i-PRF) is a platelet concentrate that has been extensively used for multiple medical purposes and is a valuable adjunct for the regeneration of damaged tissues in surgical procedures. The enriched bioactive substances in i-PRF are responsible for speeding the wound healing process. Infection of biofilm producing bacteria in surgical wounds is becoming a serious threat. Research in this field is focused on new strategies to fight infections and to reduce the healing time. The present study was aimed to evaluate the in vitro antimicrobial and antibiofilm effects of i-PRF against oral pathogenic biofilm producing staphylococcus bacteria isolated from patient with dental and oral abscess. The antibacterial activity of i-PRF, was determined through broth microdilution as minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). i-PRF exhibited bactericidal activity against both non biofilm and biofilm producing bacteria. i-PRF could be potential antimicrobial peptide used to combat postoperative infections caused by biofilm producing staphylococcus.}, } @article {pmid31888471, year = {2019}, author = {Slade, EA and Thorn, RMS and Young, A and Reynolds, DM}, title = {An in vitro collagen perfusion wound biofilm model; with applications for antimicrobial studies and microbial metabolomics.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {310}, pmid = {31888471}, issn = {1471-2180}, mesh = {Ammonia/analysis ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ceftazidime/pharmacology ; *Collagen ; Gels ; Hydrogen Cyanide/analysis ; Mass Spectrometry ; Metabolomics ; Pseudomonas aeruginosa/drug effects/physiology ; Wound Infection/*microbiology ; }, abstract = {BACKGROUND: The majority of in vitro studies of medically relevant biofilms involve the development of biofilm on an inanimate solid surface. However, infection in vivo consists of biofilm growth on, or suspended within, the semi-solid matrix of the tissue, whereby current models do not effectively simulate the nature of the in vivo environment. This paper describes development of an in vitro method for culturing wound associated microorganisms in a system that combines a semi-solid collagen gel matrix with continuous flow of simulated wound fluid. This enables culture of wound associated reproducible steady state biofilms under conditions that more closely simulate the dynamic wound environment. To demonstrate the use of this model the antimicrobial kinetics of ceftazidime, against both mature and developing Pseudomonas aeruginosa biofilms, was assessed. In addition, we have shown the potential application of this model system for investigating microbial metabolomics by employing selected ion flow tube mass spectrometry (SIFT-MS) to monitor ammonia and hydrogen cyanide production by Pseudomonas aeruginosa biofilms in real-time.

RESULTS: The collagen wound biofilm model facilitates growth of steady-state reproducible Pseudomonas aeruginosa biofilms under wound like conditions. A maximum biofilm density of 10[10] cfu slide[- 1] was achieved by 30 h of continuous culture and maintained throughout the remainder of the experiment. Treatment with ceftazidime at a clinically relevant dose resulted in a 1.2-1.6 log reduction in biofilm density at 72 h compared to untreated controls. Treatment resulted in loss of complex biofilm architecture and morphological changes to bacterial cells, visualised using confocal microscopy. When monitoring the biofilms using SIFT-MS, ammonia and hydrogen cyanide levels peaked at 12 h at 2273 ppb (±826.4) and 138 ppb (±49.1) respectively and were detectable throughout experimentation.

CONCLUSIONS: The collagen wound biofilm model has been developed to facilitate growth of reproducible biofilms under wound-like conditions. We have successfully used this method to: (1) evaluate antimicrobial efficacy and kinetics, clearly demonstrating the development of antimicrobial tolerance in biofilm cultures; (2) characterise volatile metabolite production by P. aeruginosa biofilms, demonstrating the potential use of this method in metabolomics studies.}, } @article {pmid31888149, year = {2019}, author = {Meroni, G and Soares Filipe, JF and Drago, L and Martino, PA}, title = {Investigation on Antibiotic-Resistance, Biofilm Formation and Virulence Factors in Multi Drug Resistant and Non Multi Drug Resistant Staphylococcus pseudintermedius.}, journal = {Microorganisms}, volume = {7}, number = {12}, pages = {}, pmid = {31888149}, issn = {2076-2607}, abstract = {Staphylococcus pseudintermedius is a commensal bacterium frequently isolated from canine skin and recognized as a zoonotic agent especially for dog-owners. This study focused on (a) the antibiotic-resistance phenotypes; (b) the ability to produce biofilm (slime); and (c) the dissemination of virulence factors in S. pseudintermedius strains. Seventy-three S. pseudintermedius strains were screened for antibiotic-resistance against 22 different molecules by means of Kirby-Bauer assay. The ability to produce biofilm was investigated using the microtiter plate assay (MtP) and the amplification of icaA and icaD genes. Virulence factors such as cytotoxins (lukI), enterotoxins (seC), and exfoliative toxins (siet, expA, and expB) were evaluated. The antibiotic-resistance profiles revealed 42/73 (57%) multi-drug resistant (MDR) strains and 31/73 (43%) not-MDR. All the MDR strains and 8/31 (27%) of not-MDR resulted in biofilm producers. Leukotoxin LukI was found in 70/73 (96%) of the isolates. Moreover, the enterotoxin gene seC was detected in 47/73 (64%) of the strains. All the isolates carried the siet gene, whereas expA and expB were found in 3/73 (4%) and 5/73 (7%), respectively. In conclusion, S. pseudintermedius should be considered a potential zoonotic and human agent able to carry different virulence determinants and capable of producing biofilm which facilitates horizontal gene transfer.}, } @article {pmid31887894, year = {2020}, author = {Muthuchamy, M and Govindan, R and Shine, K and Thangasamy, V and Alharbi, NS and Thillaichidambaram, M and Khaled, JM and Wen, JL and Alanzi, KF}, title = {Anti-biofilm investigation of graphene/chitosan nanocomposites against biofilm producing P. aeruginosa and K. pneumoniae.}, journal = {Carbohydrate polymers}, volume = {230}, number = {}, pages = {115646}, doi = {10.1016/j.carbpol.2019.115646}, pmid = {31887894}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Chitosan/chemistry/*pharmacology ; Drug Resistance, Multiple, Bacterial/drug effects ; Graphite/chemistry/*pharmacology ; Humans ; Klebsiella pneumoniae/*drug effects ; Nanoparticles/*chemistry/therapeutic use ; Pseudomonas aeruginosa/*drug effects ; Urinary Tract Infections/drug therapy ; }, abstract = {In this study graphene/chitosan nanoparticles (GR/CS NCs) were developed. The homogenous combination of GR and CS was confirmed by FTIR spectroscopy. The combination of CS with GR sheets reduced the XRD intensity of the GR peak in GR/CS NCs, while TEM images revealed the immobile CS coating of GR sheets. Further, the anti-biofilm activity of GR/CS NCs was tested. The tests showed that the formation of biofilm by Pseudomonas aeruginosa and Klebsiella pneumoniae was inhibited at 40□g/mL GR/CS NCs up to 94 and 92 %, respectively. The intracellular and cell surface damage of the bacteria was observed by CLSM and SEM. Also, GR/CS NCs produced a toxic effect of 90 % on Artemia franciscana at 70□g/mL upon 24 h incubation. The recorded properties of the synthesized GR/CS NCs qualify them as potential agents against multi-drug resistant bacteria.}, } @article {pmid31887516, year = {2020}, author = {Choi, PM and Li, J and Gao, J and O'Brien, JW and Thomas, KV and Thai, PK and Jiang, G and Mueller, JF}, title = {Considerations for assessing stability of wastewater-based epidemiology biomarkers using biofilm-free and sewer reactor tests.}, journal = {The Science of the total environment}, volume = {709}, number = {}, pages = {136228}, doi = {10.1016/j.scitotenv.2019.136228}, pmid = {31887516}, issn = {1879-1026}, mesh = {Biofilms ; Biomarkers ; *Sewage ; Wastewater ; Wastewater-Based Epidemiological Monitoring ; Water Pollutants, Chemical ; }, abstract = {Wastewater-based epidemiology is an increasingly popular method for analysing drugs or metabolites excreted by populations. The in-sewer transformation of biomarkers is important but often receives little consideration in published studies. Many studies publish stability under biofilm-free conditions only, which do not represent actual sewer conditions. This study aims to fill a gap in the field by comparing the wastewater stability of 33 licit drug and pharmaceutical biomarkers in biofilm-free (BFF) conditions to stability in sewer biofilm reactors. All but one biomarker was stable under BFF conditions, whereas most transformed in sewer biofilm reactors. Sewer reactor results tended to overestimate the degradation in pilot and actual sewers, whereas BFF stability had no clear relationship to stability in pilot and actual sewers. Our results provide additional basis for more informed interpretation of biofilm-free and sewer reactor stability results for past and future WBE studies.}, } @article {pmid31886204, year = {2019}, author = {Minami, M and Takase, H and Nakamura, M and Makino, T}, title = {Effect of Lonicera caerulea var. emphyllocalyx Fruit on Biofilm Formed by Porphyromonas gingivalis.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {3547858}, pmid = {31886204}, issn = {2314-6141}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms/drug effects/growth & development ; Dose-Response Relationship, Drug ; Fruit/*chemistry ; Lonicera/*chemistry ; *Plant Extracts/chemistry/pharmacology ; Porphyromonas gingivalis/*physiology/ultrastructure ; }, abstract = {Porphyromonas gingivalis is an important pathogenic anaerobic bacterium that causes aspiration pneumonia. This bacterium frequently forms biofilms in the oral cavity and in respiratory tract-associated medical devices. Bacterial colonization that occurs in association with this biofilm formation is the main reason for incurable aspiration pneumonia. The Lonicera caerulea var. emphyllocalyx (LCE) fruit has been used in folk medicine in Hokkaido, the northern part of Japan. The aim of this study was to elucidate one of the antimicrobial mechanisms of LCE methanol extract (LCEE)-the inhibitory effect of LCEE on biofilm formation by P. gingivalis. Our results show that LCEE significantly reduced biofilm formation by three different P. gingivalis isolates in a concentration- and time-dependent manner that were quantified by the adsorption of safranin red. When LCEE was added to biofilms already formed by P. gingivalis, LCEE did not degrade the biofilm. However, treatment with LCEE significantly promoted the removal of existing biofilm by vibration compared to that of control. We also confirmed biofilm formation in LCEE-treated P. gingivalis in tracheal tubes using scanning electron microscopic (SEM) analysis. Cyanidin 3-O-glucoside (C3G), one of the components of LCE, also inhibited the formation of biofilm by P. gingivalis in a concentration-dependent manner. Our results reveal that LCEE may be an effective antibacterial substance for P. gingivalis-induced aspiration pneumonia because of its role in the suppression of bacterial biofilm formation in the oral cavity.}, } @article {pmid31885632, year = {2019}, author = {Adusei, EBA and Adosraku, RK and Oppong-Kyekyeku, J and Amengor, CDK and Jibira, Y}, title = {Resistance Modulation Action, Time-Kill Kinetics Assay, and Inhibition of Biofilm Formation Effects of Plumbagin from Plumbago zeylanica Linn.}, journal = {Journal of tropical medicine}, volume = {2019}, number = {}, pages = {1250645}, pmid = {31885632}, issn = {1687-9686}, abstract = {Antimicrobial resistance (AMR) is a threat to the prevention and treatment of the increasing range of infectious diseases. There is therefore the need for renewed efforts into antimicrobial discovery and development to combat the menace. The antimicrobial activity of plumbagin isolated from roots of Plumbago zeylanica against selected organisms was evaluated for resistance modulation antimicrobial assay, time-kill kinetics assay, and inhibition of biofilm formation. The minimum inhibitory concentrations (MICs) of plumbagin and standard drugs were determined via the broth microdilution method to be 0.5 to 8 μg/mL and 0.25-128 μg/mL, respectively. In the resistance modulation study, MICs of the standard drugs were redetermined in the presence of subinhibitory concentration of plumbagin (4 μg/mL), and plumbagin was found to either potentiate or reduce the activities of these standard drugs with the highest potentiation recorded up to 12-folds for ketoconazole against Candida albicans. Plumbagin was found to be bacteriostatic and fungistatic from the time-kill kinetics study. Plumbagin demonstrated strong inhibition of biofilm formation activity at concentrations of 128, 64, and 32 μg/mL against the test microorganisms compared with ciprofloxacin. Plumbagin has been proved through this study to be a suitable lead compound in antimicrobial resistance drug development.}, } @article {pmid31885354, year = {2020}, author = {Taghizadeh, L and Karimi, A and Presterl, E and Heitzinger, C}, title = {Bayesian inversion for a biofilm model including quorum sensing.}, journal = {Computers in biology and medicine}, volume = {117}, number = {}, pages = {103582}, doi = {10.1016/j.compbiomed.2019.103582}, pmid = {31885354}, issn = {1879-0534}, mesh = {Anti-Bacterial Agents ; Bacteria ; Bayes Theorem ; *Biofilms ; *Quorum Sensing ; }, abstract = {We propose a mathematical model based on a system of partial differential equations (PDEs) for biofilms. This model describes the time evolution of growth and degradation of biofilms which depend on environmental factors. The proposed model also includes quorum sensing (QS) and describes the cooperation among bacteria when they need to resist against external factors such as antibiotics. The applications include biofilms on teeth and medical implants, in drinking water, cooling water towers, food processing, oil recovery, paper manufacturing, and on ship hulls. We state existence and uniqueness of solutions of the proposed model and implement the mathematical model to discuss numerical simulations of biofilm growth and cooperation. We also determine the unknown parameters of the presented biofilm model by solving the corresponding inverse problem. To this end, we propose Bayesian inversion techniques and the delayed-rejection adaptive-Metropolis (DRAM) algorithm for the simultaneous extraction of multiple parameters from the measurements. These quantities cannot be determined directly from the experiments or from the computational model. Furthermore, we evaluate the presented model by comparing the simulations using the estimated parameter values with the measurement data. The results illustrate a very good agreement between the simulations and the measurements.}, } @article {pmid31885074, year = {2020}, author = {Taşkan, B and Hasar, H and Lee, CH}, title = {Effective biofilm control in a membrane biofilm reactor using a quenching bacterium (Rhodococcus sp. BH4).}, journal = {Biotechnology and bioengineering}, volume = {117}, number = {4}, pages = {1012-1023}, doi = {10.1002/bit.27259}, pmid = {31885074}, issn = {1097-0290}, support = {116Y067//The Scientific and Technological Research Council of Turkey (TUBITAK)/International ; }, mesh = {Bacteria/metabolism ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Cells, Immobilized/metabolism ; Membranes, Artificial ; Oxygen/metabolism ; Quorum Sensing/*physiology ; Rhodococcus/*metabolism ; }, abstract = {The biofilm thickness in membrane biofilm reactors (MBfRs) is an important factor affecting system performance because excessive biofilm formation on the membrane surface inhibits gas diffusion to the interior of the biofilm, resulting in a significant reduction in the performance of contaminant removal. This study provides innovative insights into the control of biofilm thickness in O2 -based MBfRs by using the quorum quenching (QQ) method. The study was carried out in MBfRs operated at different gas pressures and hydraulic retention times (HRTs) using QQ beads containing Rhodococcus sp. BH4 at different amounts. The highest performance was observed in reactors operated with 0.21 ml QQ bead/cm[2] membrane surface area, 12 HRTs and 1.40 atm. Over this period, the performance increase in chemical oxygen demand (COD) removal was 25%, while the biofilm thickness on the membrane surface was determined to be 250 μm. Moreover, acetate and equivalent oxygen flux results reached 6080 and 10 640 mg·m[-2] ·d[-1] maximum values, respectively. The extracellular polymeric substances of the biofilm decreased significantly with the increase of gas pressure and QQ beads amount. Polymerase chain reaction denaturing gradient gel electrophoresis results showed that the microbial community in the MBfR system changed depending on operating conditions and bead amount. The results showed that the QQ method was an effective method to control the biofilm thickness in MBfR and provide insights for future research.}, } @article {pmid31882963, year = {2019}, author = {Cambronel, M and Tortuel, D and Biaggini, K and Maillot, O and Taupin, L and Réhel, K and Rincé, I and Muller, C and Hardouin, J and Feuilloley, M and Rodrigues, S and Connil, N}, title = {Epinephrine affects motility, and increases adhesion, biofilm and virulence of Pseudomonas aeruginosa H103.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {20203}, pmid = {31882963}, issn = {2045-2322}, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Cell Line ; Epinephrine/*pharmacology ; Humans ; Pseudomonas aeruginosa/*drug effects/pathogenicity/physiology ; Virulence/*drug effects ; }, abstract = {Microbial endocrinology has demonstrated for more than two decades, that eukaryotic substances (hormones, neurotransmitters, molecules of the immune system) can modulate the physiological behavior of bacteria. Among them, the hormones/neurotransmitters, epinephrine (Epi) and norepinephrine (NE), released in case of stress, physical effort or used in medical treatment, were shown to be able to modify biofilm formation in various bacterial species. In the present study, we have evaluated the effect of Epi on motility, adhesion, biofilm formation and virulence of Pseudomonas aeruginosa, a bacterium linked to many hospital-acquired infections, and responsible for chronic infection in immunocompromised patients including persons suffering from cystic fibrosis. The results showed that Epi increased adhesion and biofilm formation of P. aeruginosa, as well as its virulence towards the Galleria mellonella larvae in vivo model. Deciphering the sensor of this molecule in P. aeruginosa and the molecular mechanisms involved may help to find new strategies of treatment to fight against this bacterium.}, } @article {pmid31882881, year = {2019}, author = {Shi, L and Wu, Y and Yang, C and Ma, Y and Zhang, QZ and Huang, W and Zhu, XY and Yan, YJ and Wang, JX and Zhu, T and Qu, D and Zheng, CQ and Zhao, KQ}, title = {Effect of nicotine on Staphylococcus aureus biofilm formation and virulence factors.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {20243}, pmid = {31882881}, issn = {2045-2322}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects/growth & development ; Ganglionic Stimulants/pharmacology ; *Gene Expression Regulation, Bacterial ; Humans ; Nicotine/*pharmacology ; Nose Diseases/diagnosis/microbiology ; Sinusitis/diagnosis/microbiology ; Staphylococcal Infections/diagnosis/microbiology ; Staphylococcus aureus/*drug effects/genetics/pathogenicity ; Virulence/genetics ; Virulence Factors/*genetics ; }, abstract = {Staphylococcus aureus is a common pathogen in chronic rhinosinusitis (CRS) patients, the pathogenesis of which involves the ability to form biofilms and produce various virulence factors. Tobacco smoke, another risk factor of CRS, facilitates S. aureus biofilm formation; however, the mechanisms involved are unclear. Here, we studied the effect of nicotine on S. aureus biofilm formation and the expression of virulence-related genes. S. aureus strains isolated from CRS patients and a USA300 strain were treated with nicotine or were untreated (control). Nicotine-treated S. aureus strains showed dose-dependent increases in biofilm formation, lower virulence, enhanced initial attachment, increased extracellular DNA release, and a higher autolysis rate, involving dysregulation of the accessory gene regulator (Agr) quorum-sensing system. Consequently, the expression of autolysis-related genes lytN and atlA, and the percentage of dead cells in biofilms was increased. However, the expression of virulence-related genes, including hla, hlb, pvl, nuc, ssp, spa, sigB, coa, and crtN was downregulated and there was reduced bacterial invasion of A549 human alveolar epithelial cells. The results of this study indicate that nicotine treatment enhances S. aureus biofilm formation by promoting initial attachment and extracellular DNA release but inhibits the virulence of this bacterium.}, } @article {pmid31882539, year = {2020}, author = {Samanta, S and Biswas, P and Banerjee, A and Bose, A and Siddiqui, N and Nambi, S and Saini, DK and Visweswariah, SS}, title = {A universal stress protein in Mycobacterium smegmatis sequesters the cAMP-regulated lysine acyltransferase and is essential for biofilm formation.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {6}, pages = {1500-1516}, pmid = {31882539}, issn = {1083-351X}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cyclic AMP/*metabolism ; Gene Deletion ; Genes, Bacterial ; Heat-Shock Proteins/genetics/*metabolism ; Humans ; Lysine Acetyltransferases/*metabolism ; Mycobacterium Infections, Nontuberculous/microbiology ; Mycobacterium smegmatis/genetics/*physiology ; Operon ; }, abstract = {Universal stress proteins (USPs) are present in many bacteria, and their expression is enhanced under various environmental stresses. We have previously identified a USP in Mycobacterium smegmatis that is a product of the msmeg_4207 gene and is a substrate for a cAMP-regulated protein lysine acyltransferase (KATms; MSMEG_5458). Here, we explored the role of this USP (USP[4207]) in M. smegmatis and found that its gene is present in an operon that also contains genes predicted to encode a putative tripartite tricarboxylate transporter (TTT). Transcription of the TTT-usp[4207] operon was induced in the presence of citrate and tartrate, perhaps by the activity of a divergent histidine kinase-response regulator gene pair. A usp[4207]-deleted strain had rough colony morphology and reduced biofilm formation compared with the WT strain; however, both normal colony morphology and biofilm formation were restored in a Δusp[4207]Δkatms strain. We identified several proteins whose acetylation was lost in the Δkatms strain, and whose transcript levels increased in M. smegmatis biofilms along with that of USP[4207], suggesting that USP[4207] insulates KATms from its other substrates in the cell. We propose that USP[4207] sequesters KATms from diverse substrates whose activities are down-regulated by acylation but are required for biofilm formation, thus providing a defined role for this USP in mycobacterial physiology and stress responses.}, } @article {pmid31880890, year = {2019}, author = {Olender, A and Bogut, A and Magryś, A and Tabarkiewicz, J}, title = {Cytokine Levels in the In Vitro Response of T Cells to Planktonic and Biofilm Corynebacterium amycolatum.}, journal = {Polish journal of microbiology}, volume = {68}, number = {4}, pages = {457-464}, pmid = {31880890}, issn = {2544-4646}, mesh = {*Biofilms ; Cell Line ; Corynebacterium/genetics/immunology/*physiology ; Corynebacterium Infections/genetics/*immunology/microbiology ; Cytokines/genetics/*immunology ; Humans ; Interleukin-10/genetics/immunology ; Interleukin-1beta/genetics/immunology ; Interleukin-6/genetics/immunology ; Interleukin-8/genetics/immunology ; Plankton/genetics/physiology ; T-Lymphocytes/*immunology ; }, abstract = {Unravelling of the interplay between the immune system and non-diphtheria corynebacteria would contribute to understanding their increasing role as medically important microorganisms. We aimed at the analysis of pro- (TNF, IL-1β, IL-6, IL-8, and IL-12p70) and anti-inflammatory (IL-10) cytokines produced by Jurkat T cells in response to planktonic and biofilm Corynebacterium amycolatum. Two reference strains: C. amycolatum ATCC 700207 (R-CA), Staphylococcus aureus ATCC 25923 (R-SA), and ten clinical strains of C. amycolatum (C-CA) were used in the study. Jurkat T cells were stimulated in vitro by the planktonic-conditioned medium (PCM) and biofilm-conditioned medium (BCM) derived from the relevant cultures of the strains tested. The cytokine concentrations were determined in the cell culture supernatants using the flow cytometry. The levels of the cytokines analyzed were lower after stimulation with the BCM when compared to the PCM derived from the cultures of C-CA; statistical significance (p < 0.05) was observed for IL-1β, IL-12 p70, and IL-10. Similarly, planktonic R-CA and R-SA stimulated a higher cytokine production than their biofilm counterparts. The highest levels of pro-inflammatory IL-8, IL-1β, and IL-12p70 were observed after stimulation with planktonic R-SA whereas the strongest stimulation of anti-inflammatory IL-10 was noted for the BCM derived from the mixed culture of both reference species. Our results are indicative of weaker immunostimulatory properties of the biofilm C. amycolatum compared to its planktonic form. It may play a role in the persistence of biofilm-related infections. The extent of the cytokine response can be dependent on the inherent virulence of the infecting microorganism. Unravelling of the interplay between the immune system and non-diphtheria corynebacteria would contribute to understanding their increasing role as medically important microorganisms. We aimed at the analysis of pro- (TNF, IL-1β, IL-6, IL-8, and IL-12p70) and anti-inflammatory (IL-10) cytokines produced by Jurkat T cells in response to planktonic and biofilm Corynebacterium amycolatum. Two reference strains: C. amycolatum ATCC 700207 (R-CA), Staphylococcus aureus ATCC 25923 (R-SA), and ten clinical strains of C. amycolatum (C-CA) were used in the study. Jurkat T cells were stimulated in vitro by the planktonic-conditioned medium (PCM) and biofilm-conditioned medium (BCM) derived from the relevant cultures of the strains tested. The cytokine concentrations were determined in the cell culture supernatants using the flow cytometry. The levels of the cytokines analyzed were lower after stimulation with the BCM when compared to the PCM derived from the cultures of C-CA; statistical significance (p < 0.05) was observed for IL-1β, IL-12 p70, and IL-10. Similarly, planktonic R-CA and R-SA stimulated a higher cytokine production than their biofilm counterparts. The highest levels of pro-inflammatory IL-8, IL-1β, and IL-12p70 were observed after stimulation with planktonic R-SA whereas the strongest stimulation of anti-inflammatory IL-10 was noted for the BCM derived from the mixed culture of both reference species. Our results are indicative of weaker immunostimulatory properties of the biofilm C. amycolatum compared to its planktonic form. It may play a role in the persistence of biofilm-related infections. The extent of the cytokine response can be dependent on the inherent virulence of the infecting microorganism.}, } @article {pmid31880259, year = {2020}, author = {Abdalla, SSI and Katas, H and Azmi, F and Busra, MFM}, title = {Antibacterial and Anti-Biofilm Biosynthesised Silver and Gold Nanoparticles for Medical Applications: Mechanism of Action, Toxicity and Current Status.}, journal = {Current drug delivery}, volume = {17}, number = {2}, pages = {88-100}, doi = {10.2174/1567201817666191227094334}, pmid = {31880259}, issn = {1875-5704}, mesh = {Animals ; *Anti-Bacterial Agents/administration & dosage/chemistry/toxicity ; Biofilms/drug effects ; *Gold/administration & dosage/chemistry/toxicity ; Humans ; *Metal Nanoparticles/administration & dosage/chemistry/toxicity ; *Silver/administration & dosage/chemistry/toxicity ; }, abstract = {Fast progress in nanoscience and nanotechnology has contributed to the way in which people diagnose, combat, and overcome various diseases differently from the conventional methods. Metal nanoparticles, mainly silver and gold nanoparticles (AgNPs and AuNPs, respectively), are currently developed for many applications in the medical and pharmaceutical area including as antibacterial, antibiofilm as well as anti-leshmanial agents, drug delivery systems, diagnostics tools, as well as being included in personal care products and cosmetics. In this review, the preparation of AgNPs and AuNPs using different methods is discussed, particularly the green or bio- synthesis method as well as common methods used for their physical and chemical characterization. In addition, the mechanisms of the antimicrobial and anti-biofilm activity of AgNPs and AuNPs are discussed, along with the toxicity of both nanoparticles. The review will provide insight into the potential of biosynthesized AgNPs and AuNPs as antimicrobial nanomaterial agents for future use.}, } @article {pmid31879573, year = {2019}, author = {Bekliz, M and Brandani, J and Bourquin, M and Battin, TJ and Peter, H}, title = {Benchmarking protocols for the metagenomic analysis of stream biofilm viromes.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e8187}, pmid = {31879573}, issn = {2167-8359}, abstract = {Viruses drive microbial diversity, function and evolution and influence important biogeochemical cycles in aquatic ecosystems. Despite their relevance, we currently lack an understanding of their potential impacts on stream biofilm structure and function. This is surprising given the critical role of biofilms for stream ecosystem processes. Currently, the study of viruses in stream biofilms is hindered by the lack of an optimized protocol for their extraction, concentration and purification. Here, we evaluate a range of methods to separate viral particles from stream biofilms, and to concentrate and purify them prior to DNA extraction and metagenome sequencing. Based on epifluorescence microscopy counts of viral-like particles (VLP) and DNA yields, we optimize a protocol including treatment with tetrasodium pyrophosphate and ultra-sonication to disintegrate biofilms, tangential-flow filtration to extract and concentrate VLP, followed by ultracentrifugation in a sucrose density gradient to isolate VLP from the biofilm slurry. Viromes derived from biofilms sampled from three different streams were dominated by Siphoviridae, Myoviridae and Podoviridae and provide first insights into the viral diversity of stream biofilms. Our protocol optimization provides an important step towards a better understanding of the ecological role of viruses in stream biofilms.}, } @article {pmid31878164, year = {2019}, author = {López, Y and Soto, SM}, title = {The Usefulness of Microalgae Compounds for Preventing Biofilm Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {31878164}, issn = {2079-6382}, abstract = {Biofilms play an important role in infectious diseases. It has been estimated that most medical infections are due to bacterial biofilms, and about 60-70% of nosocomial infections are also caused by the formation of a biofilm. Historically, microalgae are an important source of bioactive compounds, having novel structures and potential biological functions that make them attractive for different industries such as food, animal feed, aquaculture, cosmetics, and pharmaceutical. Several studies have described compounds produced by microalgae and cyanobacteria species with antimicrobial activity. However, studies on the antibiofilm activity of extracts and/or molecules produced by these microorganisms are scarce. Quorum-sensing inhibitor and anti-adherent agents have, among others, been isolated from microalgae and cyanobacteria species. The use of tools such as nanotechnology increase their power of action and can be used for preventing and treating biofilm-related infections.}, } @article {pmid31877837, year = {2019}, author = {Kot, B and Sytykiewicz, H and Sprawka, I and Witeska, M}, title = {Effect of trans-Cinnamaldehyde on Methicillin-Resistant Staphylococcus aureus Biofilm Formation: Metabolic Activity Assessment and Analysis of the Biofilm-Associated Genes Expression.}, journal = {International journal of molecular sciences}, volume = {21}, number = {1}, pages = {}, pmid = {31877837}, issn = {1422-0067}, mesh = {Acrolein/*analogs & derivatives/chemistry/pharmacology ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Bacterial/*genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/physiology ; Microbial Sensitivity Tests/methods ; Polysaccharides, Bacterial/genetics ; Staphylococcal Infections/microbiology/prevention & control ; }, abstract = {The effects of trans-cinnamaldehyde (TC) on transcriptional profiles of biofilm-associated genes and the metabolic activity of two methicillin-resistant Staphylococcus aureus (MRSA) strains showing a different degree of adherence to polystyrene, were evaluated. Metabolic activity of S. aureus in biofilm was significantly decreased in the presence of TC at 1/2 minimum biofilm inhibition concentration (MBIC). Expression levels of the genes encoding laminin binding protein (eno), elastin binding protein (ebps) and fibrinogen binding protein (fib) in the presence of TC at 1/2 MBIC were lower than in untreated biofilm in both the weakly and strongly adhering strain. The highest decrease of expression level was observed in case of fib in the strongly adhering strain, in which the amount of fib transcript was 10-fold lower compared to biofilm without TC. In the presence of TC at 1/2 MBIC after 3, 6, 8 and 12 h, the expression level of icaA and icaD, that are involved in the biosynthesis of polysaccharide intercellular adhesin, was above half lower in the weakly adhering strain compared to biofilm without TC. In the strongly adhering strain the highest decrease in expression of these genes was observed after 3 and 6 h. This study showed that TC is a promising anti-biofilm agent for use in MRSA biofilm-related infections.}, } @article {pmid31877605, year = {2019}, author = {Yu, JA and Gao, XX}, title = {[Bacterial biofilm and chronic wound infection].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {35}, number = {12}, pages = {842-847}, doi = {10.3760/cma.j.issn.1009-2587.2019.12.003}, pmid = {31877605}, issn = {1009-2587}, support = {20160101141JC//Natural Science Foundation of Jilin Province of China/ ; }, mesh = {Anti-Bacterial Agents ; Bacteria ; *Bacterial Infections ; Biofilms ; Chronic Disease ; Humans ; *Wound Infection ; }, abstract = {Bacteria usually colonize, reproduce, and grow aggressively on chronic wounds in the form of biofilm. Different from free bacteria, bacteria in biofilm exhibit unique mechanism in epigenetics and biological behavior, especially in resistance to antibiotics and host immunity. In this article, we introduce the composition and structural function of bacterial biofilm, expound the drug-resistance mechanism of bacterial biofilm, discuss the clinical characteristics of bacterial biofilm infection wound and the diagnosis method of biofilm, and analyze the treatment strategy for bacterial biofilm. It is suggested that clinicians should pay more attention to bacterial biofilm infection and advocate in-depth study of bacterial biofilm in order to improve the quality of managing chronic wounds.}, } @article {pmid31877028, year = {2020}, author = {Mahasenan, KV and Batuecas, MT and De Benedetti, S and Kim, C and Rana, N and Lee, M and Hesek, D and Fisher, JF and Sanz-Aparicio, J and Hermoso, JA and Mobashery, S}, title = {Catalytic Cycle of Glycoside Hydrolase BglX from Pseudomonas aeruginosa and Its Implications for Biofilm Formation.}, journal = {ACS chemical biology}, volume = {15}, number = {1}, pages = {189-196}, pmid = {31877028}, issn = {1554-8937}, support = {R01 GM061629/GM/NIGMS NIH HHS/United States ; R35 GM131685/GM/NIGMS NIH HHS/United States ; P30 DK089507/DK/NIDDK NIH HHS/United States ; }, mesh = {*Biofilms ; Catalysis ; Catalytic Domain ; Cell Membrane/metabolism ; Crystallography, X-Ray ; Gene Expression Regulation ; Glycoside Hydrolases/genetics/*metabolism ; Humans ; Hydrolysis ; Models, Molecular ; Mutation ; Peptidoglycan/*metabolism ; Polysaccharides/*chemistry ; Protein Binding ; Protein Multimerization ; Pseudomonas aeruginosa/*enzymology/genetics ; Structure-Activity Relationship ; }, abstract = {BglX is a heretofore uncharacterized periplasmic glycoside hydrolase (GH) of the human pathogen Pseudomonas aeruginosa. X-ray analysis identifies it as a protein homodimer. The two active sites of the homodimer comprise catalytic residues provided by each monomer. This arrangement is seen in <2% of the hydrolases of known structure. In vitro substrate profiling shows BglX is a catalyst for β-(1→2) and β-(1→3) saccharide hydrolysis. Saccharides with β-(1→4) or β-(1→6) bonds, and the β-(1→4) muropeptides from the cell-wall peptidoglycan, are not substrates. Additional structural insights from X-ray analysis (including structures of a mutant enzyme-derived Michaelis complex, two transition-state mimetics, and two enzyme-product complexes) enabled the comprehensive description of BglX catalysis. The half-chair ([4]H3) conformation of the transition-state oxocarbenium species, the approach of the hydrolytic water molecule to the oxocarbenium species, and the stepwise release of the two reaction products were also visualized. The substrate pattern for BglX aligns with the [β-(1→2)-Glc]x and [β-(1→3)-Glc]x periplasmic osmoregulated periplasmic glucans, and possibly with the Psl exopolysaccharides, of P. aeruginosa. Both polysaccharides are implicated in biofilm formation. Accordingly, we show that inactivation of the bglX gene of P. aeruginosa PAO1 attenuates biofilm formation.}, } @article {pmid31875569, year = {2020}, author = {Lv, PL and Shi, LD and Dong, QY and Rittmann, B and Zhao, HP}, title = {How nitrate affects perchlorate reduction in a methane-based biofilm batch reactor.}, journal = {Water research}, volume = {171}, number = {}, pages = {115397}, doi = {10.1016/j.watres.2019.115397}, pmid = {31875569}, issn = {1879-2448}, mesh = {*Biofilms ; Bioreactors ; Methane ; Nitrates ; Oxidation-Reduction ; *Perchlorates ; }, abstract = {Nitrate (NO3[-]) affected perchlorate (ClO4[-]) reduction in a membrane batch biofilm reactor (MBBR), even though the electron donor, CH4, was available well in excess of its demand. For example, the perchlorate-reduction rate was 1.7 mmol/m[2]-d when perchlorate was the sole electron acceptor, but it dropped to 0.64 mmol/m[2]-d when nitrate also was present. The perchlorate-reduction rate returned to 1.60 mmol/m[2]-d after all nitrate was consumed. Denitratisoma and Azospirillum were main genera involved in perchlorate and nitrate reduction, and both could utilize NO3[-] and ClO4[-] as electron acceptors. Results of the reverse transcription-polymerase chain reaction (RT-PCR) showed that transcript abundances of nitrate reductase (narG), nitrite reductase (nirS), and perchlorate reductase (pcrA) increased when the perchlorate and nitrate concentrations were higher. Specifically, pcrA transcripts correlated to the sum of perchlorate and nitrate, rather than perchlorate individually. Analysis based on Density Functional Theory (DFT) suggests that bacteria able to utilize both acceptors, preferred NO3[-] over ClO4[-] due to nitrate reduction having lower energy barriers for proton and electron transfers.}, } @article {pmid31874434, year = {2020}, author = {Xu, S and Xing, Y and Liu, S and Luo, X and Chen, W and Huang, Q}, title = {Co-effect of minerals and Cd(II) promoted the formation of bacterial biofilm and consequently enhanced the sorption of Cd(II).}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {258}, number = {}, pages = {113774}, doi = {10.1016/j.envpol.2019.113774}, pmid = {31874434}, issn = {1873-6424}, mesh = {Adsorption ; Bacteria/*growth & development/metabolism ; *Biofilms ; Cadmium/*metabolism ; Minerals/*metabolism ; Soil Pollutants/*metabolism ; }, abstract = {Heavy metal pollution is very common in soils. Soils are complex systems including minerals, bacteria, and various other substances. In Cd(II) contaminated soil, the combined effects of clay minerals and heavy metals on bacterial biofilm and Cd(II) adsorption are unappreciated. Our study showed that the combination of clay minerals (goethite, kaolinite, and montmorillonite) and heavy metals promoted Serratia marcescens S14 biofilm development significantly more than clay minerals or Cd(II) alone. The amount of biofilm after binary treatment with clay minerals and Cd(II) was 2.3-7.3 times than that in control. Mineral-induced cell death and the expression of the fimA, bsmA, and eps were key players in biofilm formation. Binary treatment with montmorillonite and Cd(II) significantly enhanced biofilm development and consequently increased the adsorption of Cd(II). Cd(II) removal is the result of co-adsorption of bacteria and minerals. Bacterial biofilm played an important role in Cd(II) adsorption. FTIR spectroscopy showed the components of biofilm were not affected by minerals and revealed the functional groups -OH, -NH, -CH2, -SH, -COO participated in Cd(II) immobilization. Our findings are of fundamental significance for understanding how minerals and Cd(II) affect biofilms and thereby enhance Cd(II) adsorption and predicting the mobility and fate of heavy metals in heavy metal-contaminated soil.}, } @article {pmid31874422, year = {2020}, author = {Wang, L and Chen, W and Song, X and Li, Y and Zhang, W and Zhang, H and Niu, L}, title = {Cultivation substrata differentiate the properties of river biofilm EPS and their binding of heavy metals: A spectroscopic insight.}, journal = {Environmental research}, volume = {182}, number = {}, pages = {109052}, doi = {10.1016/j.envres.2019.109052}, pmid = {31874422}, issn = {1096-0953}, mesh = {*Biofilms ; Copper ; *Extracellular Polymeric Substance Matrix ; *Metals, Heavy ; Rivers ; }, abstract = {River biofilms inevitably serve as recipients of heavy metals including copper (Cu) and cadmium (Cd) following their introduction in fluvial systems. Nevertheless, the effects of cultivation substrata on the characteristics of river biofilm extracellular polymeric substances (EPS) and the binding behaviors of heavy metals on biofilms remain unclear. Integrating spectroscopic methods with chemometric analyses, we explored the binding behaviors of Cu(II) and Cd(II) onto biofilm EPS cultivated from two representative substrata at the molecular level. Chemical analysis revealed that biofilm cultivated on polyethylene (PE) pieces contained more non-fluorescent protein fractions, whereas EPS from periphyton grown on mineral, i.e., cobblestones was richer in aromatic fractions and polysaccharides. Excitation-emmision matrix combined with parallel factor analysis suggested a stronger interaction between fluorophores in periphytic EPS with Cu(II) compared to fluorophores in plastic biofilm EPS. Integrated use of infrared spectroscopy and two-dimensional correlation analyses revealed that, during the heavy metal binding processes, the amines and phenolics in plastic biofilm EPS gave the fastest responses to metal binding. While the amides and the aliphatic fractions in periphytic EPS showed a preferential binding to heavy metals. This study differentiates the effects of cultivation substrata on structuring the biofilm EPS characteristics and offers new insights into the environmental behaviors of heavy metal discharge into fluvial systems in river biofilm matrix.}, } @article {pmid31873260, year = {2019}, author = {Wadia, R}, title = {Biofilm removal.}, journal = {British dental journal}, volume = {227}, number = {12}, pages = {1041}, doi = {10.1038/s41415-019-1110-0}, pmid = {31873260}, issn = {1476-5373}, mesh = {Biofilms ; *Dental Implants ; Glycine ; Mouth ; *Sodium Bicarbonate ; }, } @article {pmid31873259, year = {2019}, author = {Wadia, R}, title = {Biofilm as a risk factor in implant treatment.}, journal = {British dental journal}, volume = {227}, number = {12}, pages = {1041}, doi = {10.1038/s41415-019-1055-3}, pmid = {31873259}, issn = {1476-5373}, mesh = {Biofilms ; *Dental Implants ; Risk Factors ; }, } @article {pmid31871084, year = {2020}, author = {Kolenda, C and Josse, J and Medina, M and Fevre, C and Lustig, S and Ferry, T and Laurent, F}, title = {Evaluation of the Activity of a Combination of Three Bacteriophages Alone or in Association with Antibiotics on Staphylococcus aureus Embedded in Biofilm or Internalized in Osteoblasts.}, journal = {Antimicrobial agents and chemotherapy}, volume = {64}, number = {3}, pages = {}, pmid = {31871084}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriophages/*pathogenicity ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Osteoblasts/*microbiology ; Staphylococcus aureus/*drug effects/*virology ; Vancomycin/pharmacology ; }, abstract = {Staphylococcus aureus is responsible for difficult-to-treat bone and joint infections (BJIs). This is related to its ability to form biofilm and to be internalized and persist inside osteoblasts. Recently, bacteriophage therapy has emerged as a promising option to improve treatment of such infections, but data on its activity against the specific bacterial lifestyles presented above remain scarce. We evaluated the activity of a combination of three bacteriophages, recently used for compassionate treatment in France, against S. aureus HG001 in a model of staphylococcal biofilm and a model of osteoblasts infection, alone or in association with vancomycin or rifampin. The activity of bacteriophages against biofilm-embedded S. aureus was dose dependent. In addition, synergistic effects were observed when bacteriophages were combined with antibiotics used at the lowest concentrations. Phage penetration into osteoblasts was observed only when the cells were infected, suggesting a S. aureus-dependent Trojan horse mechanism for internalization. The intracellular bacterial count of bacteria in infected osteoblasts treated with bacteriophages as well as with vancomycin was significantly higher than in cells treated with lysostaphin, used as a control condition, owing to the absence of intracellular activity and the rapid killing of bacteria released after the death of infected cells. These results suggest that bacteriophages are both inactive in the intracellular compartment after being internalized in infected osteoblasts and present a delayed killing effect on bacteria released after cell lysis into the extracellular compartment, which avoids preventing them from infecting other osteoblasts. The combination of bacteriophages tested was highly active against S. aureus embedded in biofilm but showed no activity against intracellular bacteria in the cell model used.}, } @article {pmid31870707, year = {2020}, author = {Lin, S and Rong, K and Lamichhane, KM and Babcock, RW and Kirs, M and Cooney, MJ}, title = {Anaerobic-aerobic biofilm-based digestion of chemical contaminants of emerging concern (CEC) and pathogen indicator organisms in synthetic wastewater.}, journal = {Bioresource technology}, volume = {299}, number = {}, pages = {122554}, doi = {10.1016/j.biortech.2019.122554}, pmid = {31870707}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Escherichia coli ; Estrogens ; Estrone ; Waste Disposal, Fluid ; *Wastewater ; *Water Pollutants, Chemical ; }, abstract = {The efficacy of biofilm based anaerobic-aerobic treatment to reduce caffeine, carbamazepine, and three estrogens (Estrone (E1), 17β-estradiol (E2), and 17α-ethynylestradiol (EE2)), as well as E. coli (CN-13) and F+ specific coliphage (MS2), from synthetic wastewater was investigated. Results showed no observable reduction of carbamazepine by either anaerobic or aerobic biofilms over a dosing period of 51-days followed by an additional 23 days of observation. Caffeine, by contrast, was reduced by 11.09% in the upflow anaerobic packed bed biofilm reactor (UAnPBBR) and by 91.90% in the aerobic trickling filter biofilm reactor (TF). Estrone (E1) and 17β-estradiol (E2) showed minimal reduction in the UAnPBBR but 99.67% reduction in the TF, while EE2 was reduced 1.62% in the AnPBBR and 20.36% in the TF. On average, a 3-log reduction of E. coli (CN-13) and a 1-log reduction of F+ specific coliphage (MS2) concentration was observed across the overall reactor system.}, } @article {pmid31870585, year = {2020}, author = {Abrantes, PMDS and Africa, CWJ}, title = {Measuring Streptococcus mutans, Streptococcus sanguinis and Candida albicans biofilm formation using a real-time impedance-based system.}, journal = {Journal of microbiological methods}, volume = {169}, number = {}, pages = {105815}, doi = {10.1016/j.mimet.2019.105815}, pmid = {31870585}, issn = {1872-8359}, mesh = {Biofilms/*growth & development ; Candida albicans/*growth & development ; Dental Caries/microbiology ; *Electric Impedance ; Microbial Interactions/physiology ; Mouth/microbiology ; Streptococcus mutans/*growth & development ; Streptococcus sanguis/*growth & development ; }, abstract = {Candida albicans and streptococci are amongst the most common fungal and bacterial organisms present in the oral cavity, with a growing body of evidence implicating C. albicans in increased caries severity and in the formation of the cariogenic biofilm. However, the interactive mechanisms between cariogenic streptococci and Candida are yet to be elucidated. In this study, the real-time biofilm formation of C. albicans, S. mutans and S. sanguinis was assessed individually and in combination using the xCELLigence system, an impedance-based microbial biofilm monitoring system. The impedance signal was the highest for C. albicans, followed by S. mutans and S. sanguinis. Although the streptococcal mixed adhesion was found to follow a similar trend to that of S. sanguinis, the introduction of C. albicans resulted in higher adhesion patterns, with the combined growth of S. sanguinis and C. albicans and the combination of all three species resulting in higher biofilm formation than any of the individual organisms over time. This study, the first to use impedance for real-time monitoring of interkingdom biofilms, adds to the body of evidence that C. albicans and oral streptococcal adhesion are interlinked and suggests that interkingdom interactions induce changes in the oral biofilm dynamics over time.}, } @article {pmid31869669, year = {2020}, author = {Zhou, M and Xu, Y and Ouyang, P and Ling, J and Cai, Q and Huang, L and Zhou, X and Zheng, L}, title = {Evolution and distribution of resistance genes and bacterial community in water and biofilm of a simulated fish-duck integrated pond with stress.}, journal = {Chemosphere}, volume = {245}, number = {}, pages = {125549}, doi = {10.1016/j.chemosphere.2019.125549}, pmid = {31869669}, issn = {1879-1298}, mesh = {Agriculture ; Animals ; Aquaculture ; Bacteria/drug effects ; Bacterial Proteins ; Biofilms/drug effects ; China ; Drug Resistance, Microbial/*genetics ; Ducks ; Fishes/genetics ; *Genes, Bacterial ; Integrons ; Ponds/*microbiology ; Seafood ; Water ; beta-Lactamases ; }, abstract = {Integrated fish-duck pond is a common circular farming model in South China, besides, it is also hot-spot for the co-selection of antibiotic resistance genes (ARGs). The aim of this study was to investigate the effects of duck manure, As and cefotaxime on the bacterial community, and the evolution and distribution of ARGs and metal(loid) resistance genes (MRGs) in water and biofilm. Five groups of fish tanks included a control and four test groups. The experimental period lasted for 100 days. Six ARGs (CIT, DHA, EBC, FOX, MOX, TEM), two MRGs (arsB, arsC), and two integron genes (intI1, intI2) were tracked and detected in water and biofilm. The results showed that duck manure brought ARGs and MRGs into fish tanks. Stress factors (cefotaxime, As) increased the relative abundance of resistance genes, and this was positively correlated with stress concentrations. The biofilm was visible significantly at the end of stage 3, and the total relative abundance of resistance genes in biofilm was higher than water from stage 5 onwards. Evolution of AmpC β-lactamase resistance genes was more obvious than MRGs, especially for MOX, which increased by 3 orders of magnitude. The abundance of Flavobacterium was higher in biofilm than in water. Moreover, correlation analysis showed that both arsB and MOX were significantly correlated with intI1 (p < 0.05), which suggested a potentially dissemination risk of resistance genes. This study provides a reference for health risk assessment in integrated aquaculture environment contaminated with duck manure, antibiotics and metalloids.}, } @article {pmid31869602, year = {2020}, author = {Chien, HW and Chen, XY and Tsai, WP and Lee, M}, title = {Inhibition of biofilm formation by rough shark skin-patterned surfaces.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {186}, number = {}, pages = {110738}, doi = {10.1016/j.colsurfb.2019.110738}, pmid = {31869602}, issn = {1873-4367}, mesh = {Animals ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Hydrophobic and Hydrophilic Interactions ; Particle Size ; Sharks ; Skin/*chemistry ; Surface Properties ; }, abstract = {In this study, we investigate the microscale structure of shark skin denticles at abdomen (A) and fin (F) locations, analyze the roughness and wetting properties related to their microstructures, and evaluate the effect of the surface properties on early bacterial attachment and biofilm formation. Microstructural analysis by scanning electron microscopy and confocal laser scanning microscopy confirmed the length (A: 165-180 μm vs. F: 145-165 μm), width (A: 86-100 μm vs. F: 64-70 μm), height (A: 10.5-13.5 μm vs. F: 6.2-8.8 μm), and density (A: 110-130 denticles/mm[2]vs. F: 80-130 denticles/mm[2]) of the denticles. The results showed that the roughness and hydrophobicity properties were affected with slight differences in the microscale architecture. The denticles with a larger width, higher ridge, and denser overlap provided a rougher and more hydrophobic surface. The microscale structure not only affected surface properties but also the biological attachment process. The microscale topography of shark skin slightly promoted bacterial attachment at an early stage, but prevented bacteria from developing biofilms. This systematic investigation provides insights into the effects of the surface topography of shark skin on its anti-fouling mechanism, which will enable the future development of various products related to human activity, such as healthcare products, underwater devices and applications, and water treatment applications.}, } @article {pmid31865470, year = {2020}, author = {Matamp, N and Bhat, SG}, title = {Genome characterization of novel lytic Myoviridae bacteriophage ϕVP-1 enhances its applicability against MDR-biofilm-forming Vibrio parahaemolyticus.}, journal = {Archives of virology}, volume = {165}, number = {2}, pages = {387-396}, doi = {10.1007/s00705-019-04493-6}, pmid = {31865470}, issn = {1432-8798}, mesh = {Aquaculture/methods ; Bacteriophages/*genetics ; Base Composition/genetics ; Biofilms ; Drug Resistance, Multiple/*genetics ; Genome, Viral/*genetics ; Genomics/methods ; Myoviridae/*genetics ; Open Reading Frames/genetics ; Phage Therapy/methods ; Phylogeny ; Vibrio parahaemolyticus/*virology ; }, abstract = {A pathogen of significance in the aquaculture sector, the Gram-negative marine bacterium Vibrio parahaemolyticus causes gastroenteritis associated with consumption of improperly prepared seafood. This bacterium can be controlled using lytic bacteriophages as an alternative to antibiotics. ϕVP-1 is a lytic phage of V. parahaemolyticus that was isolated from an aquafarm water sample with the aim of assessing its potential as a bio-control agent and determining its physicochemical properties and genomic sequence. Morphological analysis by transmission electron microscopy and phylogenetic analysis based on the large terminase subunit gene showed that this phage belongs to the family Myoviridae. It could infect multiple-drug-resistant (MDR) V. parahaemolyticus and V. alginolyticus strains of mangrove and seafood origin. With a maximum adsorption time of 30 min, ϕVP-1 has a short latent period of 10 min with burst size of 44 particles/cell. Whole-genome sequencing was done using the Illumina platform, and annotation was done using GeneMarkS and Prodigal. The 150,764bp genome with an overall G+C content of 41.84% had 203 putative protein-encoding open reading frames, one tRNA gene, and 66 predicted promoters. A number of putative DNA replication and regulation, DNA packaging and structure, and host lysis genes were identified. Comparison of the ϕVP-1 genome sequence to those of known Vibrio phages indicated little discernible DNA sequence similarity, suggesting that ϕVP-1 is a novel Vibrio phage. Sequence analysis revealed the presence of 64 potential ORFs with a T4-like genomic organization. In silico analysis suggested an obligate lytic life cycle and showed the absence of lysogeny or virulence genes. The complete sequence of ϕVP-1 was annotated and deposited in the GenBank database (accession no. MH363700). The genetic features of this novel phage suggest that it might be applicable for phage therapy against pathogenic strains of V. parahaemolyticus.}, } @article {pmid31865430, year = {2020}, author = {Hassan, HA and Ding, X and Zhang, X and Zhu, G}, title = {Fish borne Edwardsiella tarda eha involved in the bacterial biofilm formation, hemolytic activity, adhesion capability and pathogenicity.}, journal = {Archives of microbiology}, volume = {202}, number = {4}, pages = {835-842}, doi = {10.1007/s00203-019-01794-x}, pmid = {31865430}, issn = {1432-072X}, support = {KYCX19_2116//Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; }, mesh = {Animals ; Bacterial Adhesion/genetics ; Bacterial Proteins/genetics ; *Biofilms ; Caco-2 Cells ; Edwardsiella tarda/genetics/metabolism/*pathogenicity/*physiology ; Enterobacteriaceae Infections/microbiology ; Fish Diseases/microbiology ; Hemolysis/genetics ; Humans ; Mutation ; Sequence Deletion ; Virulence/genetics ; Virulence Factors/genetics ; Zebrafish ; }, abstract = {Edwardsiella tarda (E. tarda) is distributed widely in a variety of hosts including humans, other mammals and fish, and it is worthwhile to notice that E. tarda -caused fish infections lead to the most important bacterial disease in fish. Considering Eha acting as a transcriptional regulator in E. tarda strain ET13 have been reported previously, to better understand its pathogenesis due to this, a type of cell of epithelial cell line (Caco-2) infection model for the pathogen was established in the laboratory. We focused on studying various parameters such as lactate dehydrogenase release (to measure cytotoxicity) and cell adhesions, both of which are related to the bacterial pathogenesis. Furthermore biofilm formation, hemolytic activity, and adhesion to Caco-2 cells were decreased in an E.tarda mutant strain with deletion in-frame isogenic gene eha (∆eha) compared to the wild-type and the complementary strain eha[+] (an engineered construct of ∆eha expressing eha); Meanwhile, we found that hemolytic activity and biofilm formation were significantly enhanced in the strain eha[+]. Moreover, the ∆eha strain had attenuated pathogenicity in the zebrafish infection model. The data also demonstrated that the series of genes fimA, esrB, gadB, mukF, katB, and katG are regulated by eha based on a quantitative reverse transcription polymerase chain reaction tests and analysis. Thus our research data indicated that eha has an impact on hemolytic activity, biofilm formation, adhesion, and pathogenicity of pathogenic strain ET13 and plays an essential role in manifesting the virulence factors.}, } @article {pmid31865379, year = {2020}, author = {Alam, F and Catlow, D and Di Maio, A and Blair, JMA and Hall, RA}, title = {Candida albicans enhances meropenem tolerance of Pseudomonas aeruginosa in a dual-species biofilm.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {75}, number = {4}, pages = {925-935}, pmid = {31865379}, issn = {1460-2091}, support = {MR/L00903X/1/MRC_/Medical Research Council/United Kingdom ; 108876/Z/15/Z/WT_/Wellcome Trust/United Kingdom ; BB/R00966X/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms ; *Candida albicans ; Drug Tolerance ; Humans ; Meropenem/pharmacology ; *Pseudomonas aeruginosa ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterium that infects the airways of cystic fibrosis patients, surfaces of surgical and burn wounds, and indwelling medical devices. Patients are prone to secondary fungal infections, with Candida albicans being commonly co-isolated with P. aeruginosa. Both P. aeruginosa and C. albicans are able to form extensive biofilms on the surfaces of mucosa and medical devices.

OBJECTIVES: To determine whether the presence of C. albicans enhances antibiotic tolerance of P. aeruginosa in a dual-species biofilm.

METHODS: Single- and dual-species biofilms were established in microtitre plates and the survival of each species was measured following treatment with clinically relevant antibiotics. Scanning electron microscopy and confocal microscopy were used to visualize biofilm structure.

RESULTS: C. albicans enhances P. aeruginosa biofilm tolerance to meropenem at the clinically relevant concentration of 5 mg/L. This effect is specific to biofilm cultures and is dependent upon C. albicans extracellular matrix polysaccharides, mannan and glucan, with C. albicans cells deficient in glycosylation structures not enhancing P. aeruginosa tolerance to meropenem.

CONCLUSIONS: We propose that fungal mannan and glucan secreted into the extracellular matrix of P. aeruginosa/C. albicans dual-species biofilms play a central role in enhancing P. aeruginosa tolerance to meropenem, which has direct implications for the treatment of coinfected patients.}, } @article {pmid31864088, year = {2020}, author = {Saravanakumar, K and Jeevithan, E and Hu, X and Chelliah, R and Oh, DH and Wang, MH}, title = {Enhanced anti-lung carcinoma and anti-biofilm activity of fungal molecules mediated biogenic zinc oxide nanoparticles conjugated with β-D-glucan from barley.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {203}, number = {}, pages = {111728}, doi = {10.1016/j.jphotobiol.2019.111728}, pmid = {31864088}, issn = {1873-2682}, mesh = {A549 Cells ; Anti-Bacterial Agents/chemistry/pharmacology ; Antineoplastic Agents/chemistry/pharmacology ; Apoptosis/drug effects ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Glucans/*chemistry ; Hordeum/*metabolism ; Humans ; Metal Nanoparticles/*chemistry/toxicity ; Microbial Sensitivity Tests ; Plant Extracts/chemistry ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/drug effects/physiology ; Trichoderma/metabolism/physiology ; Zinc Oxide/*chemistry ; }, abstract = {This work reports the optimization, synthesis, characterization, anticancer, and antibacterial activity of the Trichoderma-β-D-glucan‑zinc oxide nanoparticles (T-β-D-glu-ZnO NPs). Firstly, the T-ZnO NPs was synthesized using the fungal mycellial water extract (FWME) derived from T. harzianum (SKCGW009) under the optimized condition of extract concentration (5.99 mL), temperature (43.11 °C), pH (8) and time (69.04 h). The successful conjugation of T-ZnO NPs with β-D-glucan (T-β-D-glu-ZnO NPs) was confirmed by PACE and FTIR. The XRD, UHR SEM, and TEM EDS results pointed the spherical shape of NPs with the mean size of 30.34 nm. Further, the XPS survey scan and high-resolution fitting of Zn2p results also claimed the successful formation of the T-β-D-glu-ZnO NPs. Cytotoxicity results indicated that the NPs were not toxic to NIH3T3 cells, while exhibited the dose-dependent inhibitory effect to human pulmonary carcinoma A549 cells. The IC50 of T-ZnO NPs and T-β-D-glu-ZnO NPs against A549 cells was 158 and 56.25 μg.mL[-1], respectively, which was also verified by fluorescent cytochemistry. Annexin V-FITC staining results indicated the presence of apoptotic cells in the NPs treated A549 cells, which was not seen in the non-treated control A549 cells. Interestingly, the number of necrosis cells was higher in the T-ZnO NPs (3.38%) comparing to T-β-D-glu -ZnO NPs (0.07%). The early or late apoptosis was found higher in the cells treated T-β-D-glu -ZnO NPs (6.43%) comparing with T-ZnO NPs (4%). These results indicated that T-ZnO NPs and T-β-D-glu-ZnO NPs induced the cancer cell death through necrosis and apoptosis pathway, respectively. The antibacterial results indicated that the NPs treatment were significantly inhibited the growth of the Staphylococcus aureus inside of roundworm and enhanced growth of roundworm. Overall, anticancer and in vitro, in vivo antibacterial studies proved the high caliber of T-β-D-glu-ZnO NPs for the further pharmaceutical evaluation.}, } @article {pmid31863153, year = {2020}, author = {Beck, S and Sehl, C and Voortmann, S and Verhasselt, HL and Edwards, MJ and Buer, J and Hasenberg, M and Gulbins, E and Becker, KA}, title = {Sphingosine is able to prevent and eliminate Staphylococcus epidermidis biofilm formation on different orthopedic implant materials in vitro.}, journal = {Journal of molecular medicine (Berlin, Germany)}, volume = {98}, number = {2}, pages = {209-219}, pmid = {31863153}, issn = {1432-1440}, support = {Gu 335/34-1//Deutsche Forschungsgemeinschaft/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Polymethacrylic Acids ; Prostheses and Implants/*microbiology ; Sphingosine/*pharmacology ; Staphylococcus epidermidis/*drug effects/physiology ; Steel ; Titanium ; }, abstract = {Periprosthetic infection (PPI) is a devastating complication in joint replacement surgery. On the background of an aging population, the number of joint replacements and associated complications is expected to increase. The capability for biofilm formation and the increasing resistance of different microbes to antibiotics have complicated the treatment of PPI, requiring the need for the development of alternative treatment options. The bactericidal effect of the naturally occurring amino alcohol sphingosine has already been reported. In our study, we demonstrate the antimicrobial efficacy of sphingosine on three different strains of biofilm producing Staphylococcus epidermidis, representing one of the most frequent microbes involved in PPI. In an in vitro analysis, sphingosine's capability for prevention and treatment of biofilm-contamination on different common orthopedic implant surfaces was tested. Coating titanium implant samples with sphingosine not only prevented implant contamination but also revealed a significant reduction of biofilm formation on the implant surfaces by 99.942%. When testing the antimicrobial efficacy of sphingosine on sessile biofilm-grown Staphylococcus epidermidis, sphingosine solution was capable to eliminate 99.999% of the bacteria on the different implant surfaces, i.e., titanium, steel, and polymethylmethacrylate. This study provides evidence on the antimicrobial efficacy of sphingosine for both planktonic and sessile biofilm-grown Staphylococcus epidermidis on contaminated orthopedic implants. Sphingosine may provide an effective and cheap treatment option for prevention and reduction of infections in joint replacement surgery. KEY MESSAGES: • Here we established a novel technology for prevention of implant colonization by sphingosine-coating of orthopedic implant materials. • Sphingosine-coating of orthopedic implants prevented bacterial colonization and significantly reduced biofilm formation on implant surfaces by 99.942%. • Moreover, sphingosine solution was capable to eliminate 99.999% of sessile biofilm-grown Staphylococcus epidermidis on different orthopedic implant surfaces.}, } @article {pmid31863146, year = {2020}, author = {Shin, B and Park, C and Park, W}, title = {OxyR-controlled surface polysaccharide production and biofilm formation in Acinetobacter oleivorans DR1.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {3}, pages = {1259-1271}, doi = {10.1007/s00253-019-10303-5}, pmid = {31863146}, issn = {1432-0614}, support = {NRF-2019R1A2C1088452//National Research Foundation of Korea/ ; }, mesh = {Acinetobacter/*genetics/*physiology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Operon ; Polysaccharides, Bacterial/*biosynthesis ; Promoter Regions, Genetic ; Repressor Proteins/*genetics ; }, abstract = {The genomes of several Acinetobacter species possess three distinct polysaccharide-producing operons [two poly-N-acetyl glucosamine (PNAG) and one K-locus]. Using a microfluidic device, an increased amount of polysaccharides and enhanced biofilm formation were observed following continuous exposure to H2O2 and removal of the H2O2-sensing key regulator, OxyR, in Acinetobacter oleivorans DR1 cells. Gene expression analysis revealed that genes located in PNAG1, but not those in PNAG2, were induced and that genes in the K-locus were expressed in the presence of H2O2. Interestingly, the expression of the K-locus gene was enhanced in the PNAG1 mutant and vice versa. The absence of either OxyR or PNAG1 resulted in enhanced biofilm formation, higher surface hydrophobicity, and increased motility, implying that K-locus-driven polysaccharide production in both the oxyR and PNAG1 deletion mutants may be related to these phenotypes. Both the oxyR and K-locus deletion mutants were more sensitive to H2O2 compared with the wildtype and PNAG1 mutant strains. Purified OxyR binds to the promoter regions of both polysaccharide operons with a higher affinity toward the K-locus promoter. Although oxidized OxyR could bind to both promoter regions, the addition of dithiothreitol further enhanced the binding efficiency of OxyR, suggesting that OxyR might function as a repressor for controlling these polysaccharide operons.}, } @article {pmid31863074, year = {2019}, author = {Kim, D and Lee, MJ and Kim, JY and Lee, D and Kwon, JS and Choi, SH}, title = {Incorporation of zwitterionic materials into light-curable fluoride varnish for biofilm inhibition and caries prevention.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {19550}, pmid = {31863074}, issn = {2045-2322}, mesh = {Biofilms/drug effects ; Dental Caries/*microbiology ; Fluorides/*chemistry/*pharmacology ; Methacrylates/chemistry ; Phosphorylcholine/analogs & derivatives/chemistry ; Streptococcus mutans/drug effects ; }, abstract = {We incorporated zwitterionic materials into light-curable fluoride varnish (LCFV) in order to inhibit biofilm accumulation and prevent dental caries, and the properties of LCFV with three different zwitterionic materials, namely, 2-methacryloyloxyethyl phosphorylcholine (MPC), carboxybetaine methacrylate (CBMA), and sulfobetaine methacrylate (SBMA) polymers (each at a weight percentage of 3%), were compared; unmodified LCFV without any zwitterionic material was used as a control. Material properties including film thickness and degree of conversion (DC) of each type of LCFV were evaluated. In addition, protein-repellent effects and inhibitory effects on Streptococcus mutans adhesion and saliva-derived biofilm accumulation of LCFV were estimated. Finally, the preventive effect of LCFV on enamel demineralization was assessed in vitro on extracted human teeth specimens stored in S. mutans-containing medium. The film thickness of LCFV significantly decreased with the incorporation of zwitterionic materials compared to the control LCFV, whereas there were no significant differences in the DC among all of the LCFV groups. Furthermore, the amount of adsorbed protein, adherent S. mutans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness and biomass were all significantly lower for LCFV with incorporated zwitterionic materials compared with the control. All LCFV groups including the control showed certain preventive effects against enamel demineralization during a 14-day immersion in the medium with S. mutans and sucrose, and the depth of demineralization was significantly lower in LCFV with zwitterionic materials than in the control. Thus, the incorporation of zwitterionic materials such as MPC, CBMA, and SBMA appears to confer superior antifouling effects to LCFV.}, } @article {pmid31862559, year = {2020}, author = {Shi, Z and Zhang, Y and Dai, R and Chen, S and Zhang, M and Jin, L and Wang, J and Zhao, W and Zhao, C}, title = {Rationally designed magnetic poly(catechol-hexanediamine) particles for bacteria removal and on-demand biofilm eradication.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {186}, number = {}, pages = {110728}, doi = {10.1016/j.colsurfb.2019.110728}, pmid = {31862559}, issn = {1873-4367}, mesh = {Biofilms/*drug effects ; Catechols/chemistry/*pharmacology ; Diamines/chemistry/*pharmacology ; Escherichia coli/*isolation & purification ; Ferric Compounds/chemistry ; Magnetic Phenomena ; Particle Size ; Polymers/chemical synthesis/chemistry/*pharmacology ; Staphylococcus aureus/*isolation & purification ; Surface Properties ; }, abstract = {In this study, we proposed a green, facile and low-cost approach for the fabrication of multifunctional particles with robust bacteria removal capability and on-demand biofilm eradication activity. Based on mussel-inspired coating of catechol and hexanediamine on Fe3O4 in aqueous solution, magnetic poly(catechol-hexanediamine) particles (Fe3O4@HDA) were prepared successfully in 1 h, at room temperature. Microbiological experiments demonstrated the Fe3O4@HDA particles could capture bacteria in water efficiently. Meanwhile, with an integration of magnetic response property and near-infrared-triggered photothermal bactericidal activity, the Fe3O4@HDA particles showed a high potential for biofilm targeting and in-situ eradication. We believe that the rationally designed magnetic poly(catechol-hexanediamine) particles could extend the applications of smart antimicrobial agents to industrial fields such as water disinfection and biofouling clean-up.}, } @article {pmid31862392, year = {2020}, author = {Prateeksha, and Bajpai, R and Yusuf, MA and Upreti, DK and Gupta, VK and Singh, BN}, title = {Endolichenic fungus, Aspergillus quandricinctus of Usnea longissima inhibits quorum sensing and biofilm formation of Pseudomonas aeruginosa PAO1.}, journal = {Microbial pathogenesis}, volume = {140}, number = {}, pages = {103933}, doi = {10.1016/j.micpath.2019.103933}, pmid = {31862392}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*isolation & purification/metabolism/pharmacology ; *Aspergillus/isolation & purification/metabolism ; Biofilms/drug effects ; Chromobacterium/drug effects/metabolism ; Indoles/metabolism ; Lichens/microbiology ; Pseudomonas aeruginosa/*drug effects ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects ; *Usnea ; Virulence Factors/metabolism ; }, abstract = {Lichens are composite organisms, comprising of a fungus (mycobiont) and a blue-green alga (photobiont). Along with the mycobiont, numerous non-obligate microfungi live in lichen thalli. These microfungi are called endolichenic fungi (ELF). In recent years, the ELF are emerging as promising natural sources because of their capability to exert unique drug molecules. The current study aimed to isolate the ELF from the lichen, Usnea longissima Ach., to control of biofilm formation and quorum sensing phenomenon in Pseudomonas aeruginosa PAO1, an opportunistic multidrug resistance pathogen that uses quorum sensing network to produce an array of pathogenic agents. Therefore, inhibiting quorum sensing to manage the infection caused by PAO1 could be the paramount alternative approach to conventional antibiotics. The isolated ELF was identified by amplifying the long subunit region of the fungal genome. The extracted metabolites of ELF (MELE) using the acetone solvent was further investigated for anti-quorum sensing activity using the biomarker strain Chromobacterium violaceum 12472 which exerts violacein pigment via the AHL mediated quorum sensing signalling. Moreover, the effect of MELE was also evaluated on the production of virulence factors and biofilm formation of P. aeruginosa PAO1. The molecular identification revealed that ELF (accession number MN171299) exhibited 100% similarity with Aspergillus quandricinctus strain CBS 135.52. The MELE showed significant anti-quorum sensing activity at the concentration of 4 mg/mL without affecting the bacterial cell viability of P. aeruginosa PAO1. The MELE diminished the production of virulence factors, including pyocyanin, protease, elastase, rhamnolipids, and extracellular polysaccharides of P. aeruginosa PAO1 in a concentration-dependent manner. The MELE also disturbed biofilm formation of P. aeruginosa PAO1. The 3-D analysis of biofilm architecture showed that the thickness and surface area covered by microcolonies was decreased as the concentration of MELE was increased. The GC-MS analysis of MELE exhibited that organic acids and fatty acids are major constituents of the MELE. The present study reports first time that the ELF, A. quandricinctus possesses potential to inhibit quorum sensing and biofilm formation of P. aeruginosa and can be further exploited for hospital and healthcare facilities.}, } @article {pmid31861483, year = {2019}, author = {Osman, KM and Kappell, AD and Fox, EM and Orabi, A and Samir, A}, title = {Prevalence, Pathogenicity, Virulence, Antibiotic Resistance, and Phylogenetic Analysis of Biofilm-Producing Listeria monocytogenes Isolated from Different Ecological Niches in Egypt: Food, Humans, Animals, and Environment.}, journal = {Pathogens (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {31861483}, issn = {2076-0817}, support = {25782//Science and Technology Development Fund/ ; }, abstract = {Serious outbreaks of foodborne disease have been caused by Listeria monocytogenes found in retail delicatessens and the severity of disease is significant, with high hospitalization and mortality rates. Little is understood about the formidable public health threat of L. monocytogenes in all four niches, humans, animals, food, and environment, in Egypt. This study analyzed the presence of L. monocytogenes collected from the four environmental niches and bioinformatics analysis was implemented to analyze and compare the data. PCR was used to detect virulence genes encoded by pathogenicity island (LIPI-1). prfA amino acid substation that causes constitutive expression of virulence was common in 77.7% of isolates. BLAST analysis did not match other isolates in the NCBI database, suggesting this may be a characteristic of the region associated with these isolates. A second group included the NH1 isolate originating in China, and BLAST analysis showed this prfA allele was shared with isolates from other global locations, such as Europe and North America. Identification of possible links and transmission pathways between the four niches helps to decrease the risk of disease in humans, to take more specific control measures in the context of disease prevention, to limit economic losses associated with food recalls, and highlights the need for treatment options.}, } @article {pmid31859706, year = {2019}, author = {Casarin, M and Pazinatto, J and Oliveira, LM and Souza, ME and Santos, RCV and Zanatta, FB}, title = {Anti-biofilm and anti-inflammatory effect of a herbal nanoparticle mouthwash: a randomized crossover trial.}, journal = {Brazilian oral research}, volume = {33}, number = {}, pages = {e062}, doi = {10.1590/1807-3107bor-2019.vol33.0062}, pmid = {31859706}, issn = {1807-3107}, mesh = {Adolescent ; Adult ; Anti-Inflammatory Agents/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/*analogs & derivatives/pharmacology ; Cross-Over Studies ; Dental Plaque/*drug therapy ; Dental Plaque Index ; Double-Blind Method ; Female ; Gingival Crevicular Fluid/drug effects ; Humans ; Male ; Melaleuca/*chemistry ; Mouthwashes/*pharmacology ; Nanoparticles/*chemistry ; Oral Hygiene/methods ; Periodontal Diseases/microbiology/prevention & control ; Statistics, Nonparametric ; Surface Properties/drug effects ; Surveys and Questionnaires ; Visual Analog Scale ; Young Adult ; }, abstract = {Laboratory evidence has demonstrated the antimicrobial effect of Melaleuca alternifolia (MEL) against oral microorganisms. This randomized, double-blind, crossover clinical trial, compared the anti-biofilm and anti-inflammatory effects of MEL nanoparticles with 0.12% chlorhexidine gluconate (CHX) on biofilm-free (BF) and biofilm-covered (BC) surfaces. Before each experimental period, the participants refrained from all oral hygiene practices for 72 hours. The 60 participants were randomly assigned to professional prophylaxis in two quadrants (Q1-Q3 or Q2-Q4), and rinsed with MEL or CHX for four days. The Quigley & Hein plaque index (QHPI), gingival crevicular fluid (GCF) volume, and participants' perceptions were assessed. CHX showed significantly lower mean QHPI on BF (2.65 ± 0.34 vs. 3.34 ± 0.33, p < 0.05) and BC surfaces (2.84 ± 0.37 vs. 3.37 ± 0.33, p < 0.05). Intragroup comparisons indicated reductions in GCF in all the groups, with significant differences only for CHX on BF surfaces (p < 0.05). Intergroup comparisons revealed no significant differences (p > 0.05). Based on individual perceptions, CHX had better taste and biofilm control, but resulted in a greater change in taste. Nevertheless, MEL demonstrated anti-inflammatory effects similar to those of CHX. Further clinical trials testing different protocols, concentrations and follow-up periods are required to establish its clinical application.}, } @article {pmid31858598, year = {2020}, author = {Lee, HJ and Oh, SY and Hong, SH}, title = {Inhibition of streptococcal biofilm formation by Aronia by extracellular RNA degradation.}, journal = {Journal of the science of food and agriculture}, volume = {100}, number = {4}, pages = {1806-1811}, doi = {10.1002/jsfa.10223}, pmid = {31858598}, issn = {1097-0010}, support = {2017R1A5A2015391//National Research Foundation of Korea (NRF)/ ; 2018R1A2B6005005//National Research Foundation of Korea (NRF)/ ; }, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Photinia/*chemistry ; Plant Extracts/isolation & purification/*pharmacology ; RNA, Bacterial/genetics/*metabolism ; Streptococcus/*drug effects/genetics/growth & development/physiology ; }, abstract = {BACKGROUND: The accumulation of oral bacterial biofilms is one of the primary etiological factors for oral diseases. Aronia melanocarpa extracts display general health benefits, including antimicrobial activities. This study evaluates the inhibitory effect of Aronia juice on oral streptococcal biofilm formation.

RESULTS: Exposure to 1/10-diluted Aronia juice for 1 min significantly decreased in vitro streptococcal biofilm formation (P < 0.001). No remarkable difference was noted in streptococcal growth by Aronia under the same conditions. Interestingly, 1 week of oral rinse with diluted Aronia juice led to significantly fewer salivary streptococcal colony-forming units (CFUs) relative to oral rinsing with tap water (P < 0.05). Furthermore, Aronia exerted an extracellular RNA-degrading effect, and RNase inhibitor alleviated Aronia-dependent streptococcal biofilm inhibition.

CONCLUSION: Aronia might inhibit initial biofilm formation by decomposing extracellular RNA, which plays an important role in bacterial biofilm formation. Our data suggest that oral rinsing with Aronia juice will aid in treating oral biofilm-dependent diseases easily and efficiently. © 2019 Society of Chemical Industry.}, } @article {pmid31858084, year = {2019}, author = {Rad, MR and Pourhajibagher, M and Rokn, AR and Barikani, HR and Bahador, A}, title = {Effect of Antimicrobial Photodynamic Therapy Using Indocyanine Green Doped with Chitosan Nanoparticles on Biofilm Formation-Related Gene Expression of Aggregatibacter actinomycetemcomitans.}, journal = {Frontiers in dentistry}, volume = {16}, number = {3}, pages = {187-193}, pmid = {31858084}, issn = {2676-296X}, abstract = {OBJECTIVES: Eradication of Aggregatibacter actinomycetemcomitans (A. actionmycetemcomitans), as an opportunistic periodontopathogen, and inhibition of its virulence factor expression require a new adjunctive therapeutic method. In this study, we accessed the expression level of rcpA gene, as a virulence factor associated with A. actinomycetemcomitans biofilm formation, following treatment by antimicrobial photodynamic therapy (aPDT) using indocyanine green (ICG) doped with chitosan nanoparticles (CS-NPs@ICG).

MATERIALS AND METHODS: CS-NPs@ICG was synthesized and examined using scanning electron microscopy (SEM). A. actinomycetemcomitans ATCC 33384 strain was treated with CS-NPs@ICG, as a photosensitizer, which was excited with a diode laser at the wavelength of 810 nm with the energy density of 31.2 J/cm2. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine the changes in rcpA gene expression level.

RESULTS: Synthetized CS-NPs@ICG was confirmed via SEM. The results revealed that CS-NPs@ICG-mediated aPDT could significantly decrease rcpA gene expression to 13.2-fold (P<0.05). There was a remarkable difference between aPDT using CS-NPs@ICG and ICG (P<0.05). The diode laser, ICG, and CS-NPs@ICG were unable to significantly downregulate rcpA gene expression (P>0.05).

CONCLUSION: aPDT with CS-NPs@ICG leads to a decrease of the virulence factor of A. actinomycetemcomitans and can be used as an adjunct to routine treatments for successful periodontal therapy in vivo.}, } @article {pmid31856459, year = {2020}, author = {Raksha, L and Gangashettappa, N and Shantala, GB and Nandan, BR and Sinha, D}, title = {Study of biofilm formation in bacterial isolates from contact lens wearers.}, journal = {Indian journal of ophthalmology}, volume = {68}, number = {1}, pages = {23-28}, pmid = {31856459}, issn = {1998-3689}, mesh = {Adolescent ; Adult ; Bacteria/*genetics ; Biofilms/*growth & development ; Contact Lenses/*microbiology ; DNA, Bacterial/*analysis ; Eye Infections, Bacterial/diagnosis/*microbiology ; Female ; Humans ; Male ; Polymerase Chain Reaction ; Young Adult ; }, abstract = {PURPOSE: To detect biofilm forming capacity of bacterial isolates obtained from the conjunctiva, contact lens and accessories of contact lens wearers using phenotypic and genotypic methods.

METHODS: Bacterial strains were collected from the conjunctiva, contact lens and lens storage cases of contact lens wearers. The phenotypic detection of biofilm production was done using the tube method and congo red agar method. The biofilm-forming related genes, icaA, of Coagulase negative Staphylococcus (CONS) and Staphylococcus aureus, and pslA, of P. aeruginosa, were detected using PCR.

RESULTS: A total of 265 bacterial isolates which included S. aureus, CONS, Pseudomonas, Nil-fermenter Gram-negative bacilli (NFGNB), Bacillus spp, Diphtheroids, Micrococci, Klebsiella pneumonia, Klebsiella oxytoca, E. coli, Proteus mirabilis, Proteus vulgaris, Citrobacter koseri, Citrobacter freundii, Enterobacter cloacae, Moraxella were obtained. Of the 265 isolates, 53.5% were moderately positive, 33.2% strongly positive and 13.2% negative for biofilm production by tube method and 36.6% were moderately positive, 40% strongly positive and 23.3% negative for biofilm production by congo red agar method. Of the four S. aureus isolates, two (50%) showed the presence of icaA gene. Of the 23 CONS isolates, three (13%) showed the presence of icaA gene. All the Pseudomonas isolates were negative for presence pslA (1119 bp) gene though most of them were phenotypically positive for biofilm formation.

CONCLUSION: Most of the bacterial isolates obtained from contact lens wearers had the potential to produce biofilms. Tube method and Congo red agar method exhibited significant statistical correlation (P-value = 0.006) and picked up a good number of biofilm-forming isolates, hence may be used for detection of biofilm production. The absence of biofilm-forming gene did not rule out the possibility for phenotypic biofilm production by bacteria.}, } @article {pmid31856361, year = {2020}, author = {Chatterjee, S and Das, S}, title = {Developmental stages of biofilm and characterization of extracellular matrix of manglicolous fungus Aspergillus niger BSC-1.}, journal = {Journal of basic microbiology}, volume = {60}, number = {3}, pages = {231-242}, doi = {10.1002/jobm.201900550}, pmid = {31856361}, issn = {1521-4028}, support = {BT/PR9465/NDB/39/360/2013//Department of Biotechnology, Ministry of Science and Technology/ ; }, mesh = {Aspergillus niger/*physiology ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/chemistry/ultrastructure ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Wetlands ; }, abstract = {Fungal biofilm is ubiquitous in natural environment. The major constituent of fungal biofilm other than biomass is the extracellular matrix (ECM), in which fungal hyphae are embedded. Physical properties of biofilms such as attachment, mechanical strength, and antibiotic resistance can be attributed to ECM. The present work probes various stages of biofilm formation by filamentous manglicolous fungus Aspergillus niger BSC-1. The spectroscopic analysis revealed that with an increase in incubation time the biofilm formation was significantly increased (p < .0001) up to 36 h. Scanning electron micrograph and confocal micrograph depicted the development of fungal biofilm comprising of six stages, that is, (a) adsorption, (b) active attachment, (c) germling and monolayer formation, (d) hyphal development and formation of ECM, (e) maturation of ECM, and (f) dispersal of spores. At maturation stage, thickness of biofilm was observed upto approximately 15 μm. Approximately, 8.1 mg of ECM materials were extracted from 20 ml of broth culture using ethanol precipitation method. Furthermore, attenuated total reflectance Fourier-transformed infrared spectroscopic analysis exhibited peaks at 3,398, 2,930, 1,571, 1,391, 1,092, 977 cm[-1] which confirmed the presence of protein, carbohydrate, and lipid in the biofilm-associated matrix.}, } @article {pmid31855718, year = {2020}, author = {Yuan, L and Lyu, P and Huang, YY and Du, N and Qi, W and Hamblin, MR and Wang, Y}, title = {Potassium iodide enhances the photobactericidal effect of methylene blue on Enterococcus faecalis as planktonic cells and as biofilm infection in teeth.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {203}, number = {}, pages = {111730}, pmid = {31855718}, issn = {1873-2682}, support = {R01 AI050875/AI/NIAID NIH HHS/United States ; R21 AI121700/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/drug effects/*physiology ; Humans ; Hydrogen Peroxide/metabolism ; Iodine/metabolism ; Light ; Methylene Blue/*pharmacology ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Photobleaching/drug effects ; Plankton/*drug effects ; Potassium Iodide/*pharmacology ; }, abstract = {OBJECTIVE: To explore the effectiveness, biosafety, photobleaching and mechanism of antimicrobial photodynamic therapy (aPDT) using methylene blue (MB) plus potassium iodide (KI), for root canal infections.

METHODS: Different combinations and concentrations of MB, KI and 660 nm LED light were used against E. faecalis in planktonic and in biofilm states by colony-forming unit (CFU), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM). Human gingival fibroblasts (HGF) were used for safety testing by Cell Counting Kit-8 (CCK8) and fluorescence microscopy (FLM). The photobleaching effect and mechanisms were analyzed.

RESULTS: KI could not only enhance MB aPDT on E. faecalis in both planktonic and biofilm states even in a hypoxic environment, but also produced a long-lasting bactericidal effect after end of the illumination. KI could accelerate photobleaching to reduce tooth staining by MB, and the mixture was harmless for HGFs. Mechanistic studies showed the generation of hydrogen peroxide and free iodine, and iodine radicals may be formed in hypoxia.

CONCLUSION: aPDT with MB plus KI could be used for root canal disinfection and clinical studies are worth pursuing.}, } @article {pmid31855457, year = {2020}, author = {Qian, W and Yang, M and Wang, T and Sun, Z and Liu, M and Zhang, J and Zeng, Q and Cai, C and Li, Y}, title = {Antibacterial Mechanism of Vanillic Acid on Physiological, Morphological, and Biofilm Properties of Carbapenem-Resistant Enterobacter hormaechei.}, journal = {Journal of food protection}, volume = {83}, number = {4}, pages = {576-583}, doi = {10.4315/JFP-19-469}, pmid = {31855457}, issn = {1944-9097}, mesh = {Anti-Bacterial Agents ; Biofilms/*drug effects ; *Carbapenems ; Enterobacter/drug effects/*physiology ; Food Preservatives/pharmacology ; Microbial Sensitivity Tests ; *Vanillic Acid/pharmacology ; }, abstract = {ABSTRACT: Many studies have evaluated the antimicrobial activity of natural products against various microorganisms, but to our knowledge there have been no studies of the possible use of natural products for their antimicrobial activity against Enterobacter hormaechei. In this study, we investigated vanillic acid (VA) for its antimicrobial activities and its modes of action against carbapenem-resistant E. hormaechei (CREH). The MIC of VA against CREH was determined by the agar diffusion method. The antibacterial action of VA against CREH was elucidated by measuring variations in intracellular ATP concentration, intracellular pH, membrane potential, and cell morphology. Moreover, the efficacy of VA against biofilm formation and VA damage to CREH cells embedded in biofilms were further explored. Our results show that VA was effective against CREH with a MIC of 0.8 mg/mL. VA could rupture the cell membrane integrity of CREH, as measured by a decrease of intracellular ATP, pH, and membrane potential, along with distinctive alternations in cell morphology. In addition, VA exerted a remarkable inhibitory effect on the biofilm formation of CREH and also killed CREH cells within biofilms. These findings show that VA has a potent antibacterial and antibiofilm activity against CREH and, hence, has the potential to be used clinically as a novel candidate agent to treat CREH infections and in the food industry as a food preservative and surface disinfectant.}, } @article {pmid31854716, year = {2019}, author = {Xu, LJ and Pan, Y and Zhang, H and Feng, X and Wei, PL and You, XY}, title = {[Effects of Aerobic Carbon Sources on Biofilm with Simultaneous Phosphate Removal and Enrichment].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {40}, number = {7}, pages = {3179-3185}, doi = {10.13227/j.hjkx.201811020}, pmid = {31854716}, issn = {0250-3301}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/microbiology ; *Carbon ; Phosphates/*isolation & purification ; Phosphorus ; Proteobacteria ; Rhodocyclaceae ; Sewage ; *Waste Disposal, Fluid ; }, abstract = {In a cyclic alternating O/A operation mode, phosphorus accumulating organisms (PAOs) can undertake phosphate removal and enrichment as the main process in wastewater treatment plants. The effects of the concentration of carbon sources during the aerobic stage on phosphate removal and enrichment performance of PAO biofilms, and the microbial population structure in the biofilms, were investigated. The results showed that the aerobic COD concentration decreased from 200 mg·L[-1] to 0 mg·L[-1], the phosphorus uptake rate improved by 1.29 times, the phosphorus concentration in effluent stabilized below 0.5 mg·L[-1], the phosphorus release rate increased by 3.56 times, and the phosphate concentration in the circulating solution increased from 27.125 mg·L[-1] to 55.91 mg·L[-1]. With respect to the change in microbial communities, the identification showed that the abundance of Proteobacteria increased by approximately two times, and the enrichment effects of Rhodocyclaceae and Anaerolineaceae increased by 2.28 and 5 times, respectively. Reducing the concentration of the carbon source in the aerobic section was beneficial to the screening and enrichment of PAOs, strengthening the removal of phosphate in the aerobic section and the release of phosphate in the anaerobic section. This resulted in an enriched phosphate solution. These observations provide a theoretical basis for future urban sewage treatment plants seeking to reduce their carbon demand.}, } @article {pmid31853764, year = {2020}, author = {Tahmasebi, H and Dehbashi, S and Jahantigh, M and Arabestani, MR}, title = {Relationship between biofilm gene expression with antimicrobial resistance pattern and clinical specimen type based on sequence types (STs) of methicillin-resistant S. aureus.}, journal = {Molecular biology reports}, volume = {47}, number = {2}, pages = {1309-1320}, pmid = {31853764}, issn = {1573-4978}, support = {9510145962//Vice chancellor for research, Hamadan university of Medical Science/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms/drug effects ; Drug Resistance, Bacterial/drug effects/*genetics ; *Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/*physiology ; Microbial Sensitivity Tests ; *Multilocus Sequence Typing ; Phylogeny ; }, abstract = {The ica genes in methicillin-resistant Staphylococcus aureus (MRSA) play an important role in biofilm formation. The aim of this study is to define effect of antibiotic resistance and clinical specimens to the expression of ica genes based on their sequence types (STs) and clonal complex (CC). One-hundred (100) S. aureus strain were collected from two teaching therapeutic centers in Hamedan, Iran. Then, the PCR, qPCR, and MLST were used to characterize strains. The results indicated that 29 (29%), 15 (15%), and 5 (5%) strain were strong, mediate, weak biofilm producer, respectively, and the icaA (17%) and icaC (14%) genes were the most abundant. However, two unique STs (3667, 491) in Iran were reported and ST30 and ST11 were the most abundant STs and CC30 and CC5 were observed among MRSA and MSSA strains. High activity in ica locus was observed among strains collected from wound and catheter strains. Also, expression level of icaA gene increased in all strains except ST30 and ST491. Moreover, the highest expression level was observed in CC1, CC7, and CC11. Likewise, activity of the icaC gene was only observed in CC5. Furthermore, the expression of all ica genes in CC5 was significantly correlated with the type of biofilm and the clinical sample. In this study demonstrated that the frequency distribution of STs and CCs in different strains of MRSA was higher than methicillin-sensitive strains. Also, the type of clinical specimen and expression of ica genes played an important role in this abundance.}, } @article {pmid31853190, year = {2019}, author = {Amin, M and Navidifar, T and Shooshtari, FS and Rashno, M and Savari, M and Jahangirmehr, F and Arshadi, M}, title = {Association Between Biofilm Formation, Structure, and the Expression Levels of Genes Related to biofilm formation and Biofilm-Specific Resistance of Acinetobacter baumannii Strains Isolated from Burn Infection in Ahvaz, Iran.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {3867-3881}, pmid = {31853190}, issn = {1178-6973}, abstract = {BACKGROUND: The ability of biofilm formation is an effective way for Acinetobacter baumannii survival from stressed conditions. This present study was aimed to evaluate the association between biofilm formation, structure, the expression levels of genes related to biofilm formation and biofilm-specific resistance of A. baumannii strains isolated from burn infections in Ahvaz, Iran.

METHODS: In this study, we assessed the antibiotic susceptibilities, ERIC-PCR typing, capacity of biofilm formation and biofilm structure of 64 A. baumannii isolates collected from burn infections. The distribution and the expression levels of genes involved in the biofilm formation including bap, ompA, abaI, pgaA and csuE were assessed by PCR and real-time PCR, respectively.

RESULTS: We classified A. baumannii isolates in 14 clonal types of ERIC-PCR. Most A. baumannii isolates were resistant to all antibiotics tested except to tigecycline and colistin and had the biofilm formation capability but with different capacities. There was a significant inverse relationship between resistance to antibiotic agents and biofilm formation. The biofilm matrix of 50 strains consisted of polysaccharides together with DNA or proteins. The genes involved in the biofilm formation were detected in both biofilm-forming and non-biofilm forming; however, the expression levels of these genes were higher in biofilm producers compared with non-producers.

CONCLUSION: The biofilm cells exhibited dramatically decreased susceptibility to antibiotic agents; hence, they have great significance for public health. Therefore, the determination of antibiotic susceptibilities in biofilm and planktonic mode, molecular typing, and capacity of biofilm formation in clinical setting is essential.}, } @article {pmid31851822, year = {2020}, author = {Condren, AR and Kahl, LJ and Boelter, G and Kritikos, G and Banzhaf, M and Dietrich, LEP and Sanchez, LM}, title = {Biofilm Inhibitor Taurolithocholic Acid Alters Colony Morphology, Specialized Metabolism, and Virulence of Pseudomonas aeruginosa.}, journal = {ACS infectious diseases}, volume = {6}, number = {4}, pages = {603-612}, pmid = {31851822}, issn = {2373-8227}, support = {K12 HD055892/HD/NICHD NIH HHS/United States ; R01 AI103369/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Metabolic Networks and Pathways/drug effects ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Taurolithocholic Acid/*pharmacology ; Virulence/drug effects ; }, abstract = {Biofilm inhibition by exogenous molecules has been an attractive strategy for the development of novel therapeutics. We investigated the biofilm inhibitor taurolithocholic acid (TLCA) and its effects on the specialized metabolism, virulence, and biofilm formation of the clinically relevant bacterium Pseudomonas aeruginosa strain PA14. Our study shows that TLCA alters the specialized metabolism, thereby affecting P. aeruginosa colony biofilm physiology. We observed an upregulation of metabolites correlated to virulence such as the siderophore pyochelin. A wax moth virulence assay confirmed that treatment with TLCA increases the virulence of P. aeruginosa. On the basis of our results, we believe that future endeavors to identify biofilm inhibitors must consider how a putative lead alters the specialized metabolism of a bacterial community to prevent pathogens from entering a highly virulent state.}, } @article {pmid31850313, year = {2019}, author = {Verderosa, AD and Totsika, M and Fairfull-Smith, KE}, title = {Bacterial Biofilm Eradication Agents: A Current Review.}, journal = {Frontiers in chemistry}, volume = {7}, number = {}, pages = {824}, pmid = {31850313}, issn = {2296-2646}, abstract = {Most free-living bacteria can attach to surfaces and aggregate to grow into multicellular communities encased in extracellular polymeric substances called biofilms. Biofilms are recalcitrant to antibiotic therapy and a major cause of persistent and recurrent infections by clinically important pathogens worldwide (e.g., Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus). Currently, most biofilm remediation strategies involve the development of biofilm-inhibition agents, aimed at preventing the early stages of biofilm formation, or biofilm-dispersal agents, aimed at disrupting the biofilm cell community. While both strategies offer some clinical promise, neither represents a direct treatment and eradication strategy for established biofilms. Consequently, the discovery and development of biofilm eradication agents as comprehensive, stand-alone biofilm treatment options has become a fundamental area of research. Here we review our current understanding of biofilm antibiotic tolerance mechanisms and provide an overview of biofilm remediation strategies, focusing primarily on the most promising biofilm eradication agents and approaches. Many of these offer exciting prospects for the future of biofilm therapeutics for a large number of infections that are currently refractory to conventional antibiotics.}, } @article {pmid31849905, year = {2019}, author = {Wu, Y and Wang, R and Xu, M and Liu, Y and Zhu, X and Qiu, J and Liu, Q and He, P and Li, Q}, title = {A Novel Polysaccharide Depolymerase Encoded by the Phage SH-KP152226 Confers Specific Activity Against Multidrug-Resistant Klebsiella pneumoniae via Biofilm Degradation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2768}, pmid = {31849905}, issn = {1664-302X}, abstract = {The increasing prevalence of infections caused by multidrug-resistant Klebsiella pneumoniae necessitates the development of alternative therapies. Here, we isolated, characterized, and sequenced a K. pneumoniae bacteriophage (SH-KP152226) that specifically infects and lyses K. pneumoniae capsular type K47. The phage SH-KP152226 contains a genome of 41,420 bp that encodes 48 predicted proteins. Among these proteins, Dep42, the gene product of ORF42, is a putative tail fiber protein and hypothetically possesses depolymerase activity. We demonstrated that recombinant Dep42 showed specific enzymatic activities in the depolymerization of the K47 capsule of K. pneumoniae and was able to significantly inhibit biofilm formation and/or degrade formed biofilms. We also showed that Dep42 could enhance polymyxin activity against K. pneumoniae biofilms when used in combination with antibiotics. These results suggest that combination of the identified novel depolymerase Dep42, encoded by the phage SH-KP152226, with antibiotics may represent a promising strategy to combat infections caused by drug-resistant and biofilm-forming K. pneumoniae.}, } @article {pmid31849901, year = {2019}, author = {Zimmermann, S and Klinger-Strobel, M and Bohnert, JA and Wendler, S and Rödel, J and Pletz, MW and Löffler, B and Tuchscherr, L}, title = {Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2762}, pmid = {31849901}, issn = {1664-302X}, abstract = {Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations.}, } @article {pmid31849660, year = {2019}, author = {Scriboni, AB and Couto, VM and Ribeiro, LNM and Freires, IA and Groppo, FC and de Paula, E and Franz-Montan, M and Cogo-Müller, K}, title = {Fusogenic Liposomes Increase the Antimicrobial Activity of Vancomycin Against Staphylococcus aureus Biofilm.}, journal = {Frontiers in pharmacology}, volume = {10}, number = {}, pages = {1401}, pmid = {31849660}, issn = {1663-9812}, abstract = {Objective: The aim of the present study was to encapsulate vancomycin in different liposomal formulations and compare the in vitro antimicrobial activity against Staphylococcus aureus biofilms. Methods: Large unilamellar vesicles of conventional (LUV VAN), fusogenic (LUVfuso VAN), and cationic (LUVcat VAN) liposomes encapsulating VAN were characterized in terms of size, polydispersity index, zeta potential, morphology, encapsulation efficiency (%EE) and in vitro release kinetics. The formulations were tested for their Minimum Inhibitory Concentration (MIC) and inhibitory activity on biofilm formation and viability, using methicillin-susceptible S. aureus ATCC 29213 and methicillin-resistant S. aureus ATCC 43300 strains. Key Findings: LUV VAN showed better %EE (32.5%) and sustained release than LUVfuso VAN, LUVcat VAN, and free VAN. The formulations were stable over 180 days at 4°C, except for LUV VAN, which was stable up to 120 days. The MIC values for liposomal formulations and free VAN ranged from 0.78 to 1.56 µg/ml against both tested strains, with no difference in the inhibition of biofilm formation as compared to free VAN. However, when treating mature biofilm, encapsulated LUVfuso VAN increased the antimicrobial efficacy as compared to the other liposomal formulations and to free VAN, demonstrating a better ability to penetrate the biofilm. Conclusion: Vancomycin encapsulated in fusogenic liposomes demonstrated enhanced antimicrobial activity against mature S. aureus biofilms.}, } @article {pmid31848281, year = {2019}, author = {Fraikin, N and Rousseau, CJ and Goeders, N and Van Melderen, L}, title = {Reassessing the Role of the Type II MqsRA Toxin-Antitoxin System in Stress Response and Biofilm Formation: mqsA Is Transcriptionally Uncoupled from mqsR.}, journal = {mBio}, volume = {10}, number = {6}, pages = {}, pmid = {31848281}, issn = {2150-7511}, mesh = {Adaptation, Biological ; *Biofilms ; DNA-Binding Proteins/*genetics/*metabolism ; Escherichia coli/physiology ; Escherichia coli Proteins/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Promoter Regions, Genetic ; Protein Binding ; Protein Biosynthesis ; *Stress, Physiological ; *Toxin-Antitoxin Systems ; Transcription, Genetic ; }, abstract = {Toxin-antitoxin (TA) systems are broadly distributed modules whose biological roles remain mostly unknown. The mqsRA system is a noncanonical TA system in which the toxin and antitoxins genes are organized in operon but with the particularity that the toxin gene precedes that of the antitoxin. This system was shown to regulate global processes such as resistance to bile salts, motility, and biofilm formation. In addition, the MqsA antitoxin was shown to be a master regulator that represses the transcription of the csgD, cspD, and rpoS global regulator genes, thereby displaying a pleiotropic regulatory role. Here, we identified two promoters located in the toxin sequence driving the constitutive expression of mqsA, allowing thereby excess production of the MqsA antitoxin compared to the MqsR toxin. Our results show that both antitoxin-specific and operon promoters are not regulated by stresses such as amino acid starvation, oxidative shock, or bile salts. Moreover, we show that the MqsA antitoxin is not a global regulator as suggested, since the expression of csgD, cspD and rpoS is similar in wild-type and ΔmqsRA mutant strains. Moreover, these two strains behave similarly in terms of biofilm formation and sensitivity to oxidative stress or bile salts.IMPORTANCE There is growing controversy regarding the role of chromosomal toxin-antitoxin systems in bacterial physiology. mqsRA is a peculiar toxin-antitoxin system, as the gene encoding the toxin precedes that of the antitoxin. This system was previously shown to play a role in stress response and biofilm formation. In this work, we identified two promoters specifically driving the constitutive expression of the antitoxin, thereby decoupling the expression of antitoxin from the toxin. We also showed that mqsRA contributes neither to the regulation of biofilm formation nor to the sensitivity to oxidative stress and bile salts. Finally, we were unable to confirm that the MqsA antitoxin is a global regulator. Altogether, our data are ruling out the involvement of the mqsRA system in Escherichia coli regulatory networks.}, } @article {pmid31847837, year = {2019}, author = {Shrestha, R and Khanal, S and Poudel, P and Khadayat, K and Ghaju, S and Bhandari, A and Lekhak, S and Pant, ND and Sharma, M and Marasini, BP}, title = {Extended spectrum β-lactamase producing uropathogenic Escherichia coli and the correlation of biofilm with antibiotics resistance in Nepal.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {18}, number = {1}, pages = {42}, pmid = {31847837}, issn = {1476-0711}, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/pharmacology ; Bacterial Outer Membrane Proteins/genetics ; *Biofilms/drug effects ; Child ; Child, Preschool ; Cross-Sectional Studies ; *Drug Resistance, Bacterial ; *Escherichia coli Infections/drug therapy/urine ; Escherichia coli Proteins/genetics ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Nepal ; Urinary Tract Infections/microbiology ; *Uropathogenic Escherichia coli/drug effects/genetics/isolation & purification ; Young Adult ; beta-Lactamases/*genetics ; }, abstract = {BACKGROUND: Urinary tract infection (UTI) is one of the frequently diagnosed infectious diseases which is caused mainly by Escherichia coli. E. coli confers resistance against the two major classes of antibiotics due to the production of extended spectrum β-lactamase enzymes (ESBL), biofilm, etc. Biofilm produced by uropathogenic E. coli (UPEC) protects from host immune system and prevent entry of antimicrobial compounds. The main objective of this cross-sectional study was to determine the correlation of biofilm production and antibiotic resistance as well as to characterize the pgaA and pgaC genes responsible for biofilm formation among uropathogenic ESBL producing E. coli.

METHODS: A total of 1977 mid-stream urine samples were examined and cultured for bacterial strain identification. ESBL was detected by combined disc method following CLSI whereas biofilm formation was analyzed by semi-quantitative method. Furthermore, the pgaA and pgaC genes responsible for biofilm formation in UPEC were detected by multiplex PCR. All the statistical analyses were done via IBM SPSS Statistics 21 where Pearson's correlation test were used to determine correlation (-1 ≥ r ≤ 1).

RESULTS: E. coli was the predominant causative agent, which accounted 159 (59.3%) of the Gram-negative bacteria, where 81 (50.9%) E. coli strains were found to be ESBL producers. In addition, 86 (54.1%) E. coli strains were found to be biofilm producers. Both the pgaA and pgaC genes were detected in 45 (93.7%) the UPEC isolates, which were both biofilm and ESBL producers. Moreover, there was a positive correlation between biofilm and ESBL production.

CONCLUSION: The analyses presented weak positive correlation between biofilm and ESBL production in which biofilm producing UPEC harbors both pgaA and pgaC genes responsible for biofilm formation.}, } @article {pmid31847713, year = {2020}, author = {Jhanji, R and Bhati, V and Singh, A and Kumar, A}, title = {Phytomolecules against bacterial biofilm and efflux pump: an in silico and in vitro study.}, journal = {Journal of biomolecular structure & dynamics}, volume = {38}, number = {18}, pages = {5500-5512}, doi = {10.1080/07391102.2019.1704884}, pmid = {31847713}, issn = {1538-0254}, mesh = {Anti-Bacterial Agents/pharmacology ; *Bacterial Proteins ; *Biofilms ; Computer Simulation ; Microbial Sensitivity Tests ; }, abstract = {Antibiotic resistance is a global threat whose incidences are increasing day by day worldwide. Thus, there is a need for new chemical entities (NCEs) or exploration of existing molecules against these types of infections. In the current investigation, we have tested the inhibitory potential of four different phytomolecules (berberine, gallic acid, piperine, and rutin) against bacterial biofilm and efflux pumps by using in-silico and in-vitro techniques. The phytomolecules (berberine, piperine, and rutin) except gallic acid have shown good interaction towards biofilm and efflux pump proteins. Further, In-vitro studies have also shown the good inhibitory effect of tested phytomolecules (berberine, rutin, and piperine) against bacterial biofilm formation and efflux pumps. In conclusion, berberine, piperine, and rutin could be the promising antibacterial candidates, particularly against resistant bacterial strains.Communicated by Ramaswamy H. Sarma.}, } @article {pmid31847295, year = {2019}, author = {Fratianni, F and Cozzolino, A and De Feo, V and Coppola, R and Ombra, MN and Nazzaro, F}, title = {Polyphenols, Antioxidant, Antibacterial, and Biofilm Inhibitory Activities of Peel and Pulp of Citrus medica L., Citrus bergamia, and Citrus medica cv. Salò Cultivated in Southern Italy.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {24}, pages = {}, pmid = {31847295}, issn = {1420-3049}, support = {PON4a2//Italian MIUR Be & Save Project 2007-2013/ ; Project CALABRIA SALUS PSR 2007-2013//Regione Calabria/ ; }, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Antioxidants/*chemistry/pharmacology ; Biofilms/*drug effects ; Citrus/*chemistry ; Escherichia coli/drug effects/physiology ; Listeria monocytogenes/drug effects/physiology ; Microbial Sensitivity Tests ; Pectobacterium carotovorum/drug effects/physiology ; Plant Extracts/chemistry ; Polyphenols/*chemistry/pharmacology ; Pseudomonas aeruginosa/drug effects/physiology ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {The aim of this paper was to study the polyphenols of peel and pulp of three Citrus taxa-Citrus medica, Citrus bergamia, and Citrus medica cv. Salò-cultivated in the Cosenza province, Southern Italy, and to evaluate their antioxidant and antibacterial activity, performed against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus, and Pectobacterium carotovorum. Furthermore, we assessed the inhibitory effect of the extracts on bacterial capacity to form biofilm, and on the metabolic activity of the cells present therein. The results indicated that such extracts could find new potential applications in the field of natural antioxidant and anti-bacterial agents in pharmaceutics, agriculture, and food fields.}, } @article {pmid31847278, year = {2019}, author = {Lamas, A and Regal, P and Vázquez, B and Cepeda, A and Franco, CM}, title = {Short Chain Fatty Acids Commonly Produced by Gut Microbiota Influence Salmonella enterica Motility, Biofilm Formation, and Gene Expression.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31847278}, issn = {2079-6382}, abstract = {Short chain fatty acids (SCFAs) are commonly produced by healthy gut microbiota and they have a protective role against enteric pathogens. SCFAs also have direct antimicrobial activity against bacterial pathogens by diffusion across the bacterial membrane and reduction of intracellular pH. Due to this antimicrobial activity, SCFAs have promising applications in human health and food safety. In this study, the minimum inhibitory concentrations (MICs) of four SCFAs (acetic acid, butyric acid, propionic acid, and valeric acid) in Salmonella strains isolated from poultry were determined. The effect of subinhibitory concentrations of SCFAs in Salmonella biofilm formation, motility, and gene expression was also evaluated. Butyric acid, propionic acid, and valeric acid showed a MIC of 3750 µg/mL in all strains tested, while the MIC of acetic acid was between 1875 and 3750 µg/mL. Subinhibitory concentrations of SCFAs significantly (p < 0.05) reduced the motility of all Salmonella strains, especially in the presence of acetic acid. Biofilm formation was also significantly (p < 0.05) lower in the presence of SCFAs in some of the Salmonella strains. Salmonella strain. Salmonella Typhimurium T7 showed significant (p < 0.05) upregulation of important virulence genes, such as invA and hilA, especially in the presence of butyric acid. Therefore, SCFAs are promising substances for the inhibition of the growth of foodborne pathogens. However, it is important to avoid the use of subinhibitory concentrations that could increase the virulence of foodborne pathogen Salmonella.}, } @article {pmid31846875, year = {2020}, author = {Hassard, F and Biddle, J and Cartmell, E and Coulon, F and Stephenson, T}, title = {Biosolids recycling impact on biofilm extracellular enzyme activity and performance of hybrid rotating biological reactors.}, journal = {The Science of the total environment}, volume = {706}, number = {}, pages = {135865}, doi = {10.1016/j.scitotenv.2019.135865}, pmid = {31846875}, issn = {1879-1026}, mesh = {*Biofilms ; *Bioreactors ; Biosolids ; Nitrogen ; Sewage ; Waste Disposal, Fluid ; }, abstract = {Biological processes for wastewater treatment is limited by extracellular enzyme activity (EEA) of the biofilm on polymeric substrates. The efficiency of biodegradation / biosorption mechanisms causing EEA and organic load removal in biofilms remains unknown. Our hypothesis was that the limiting step of biological process can be overcome by biostimulation and/or bioaugmentation of the return sludge in hybrid biofilm reactors, which leads to competition between suspended and attached bacteria and lower effective substrate to microrganism ratio. Therefore, we considered more active biosolids to perform best at enhancing reactor removal rate. To test this, the efficacy of recycling distinct bio-solids types considered to have different bacterial activity such as final effluent (FE), humus solids (HS) and recycle activated sludge (RAS) on performance improvements of rotating biofilm reactors (RBRs). These bio-solids were investigated under high organic loading rates (OLR) and solids loading rates (SLR) using pilot scale reactors receiving real municipal wastewaters. Controlled overloading of RBRs revealed that EEA improved with increasing OLR/SLR. High SLR (>3.3 kg Total Suspended Solids m[-2] d[-1]) delayed and decreased the reduction of organic and inorganic removal rates in the biological processes which commonly occurs under high OLRs. This effect was more pronounced in the highest activity solids (RAS > HS > FE) suggesting the activity and function of bio-solids was critical to improve performance of RBRs. High OLR and SLR induced efficient denitrification and organics removal within the biofilm reactor at residence times of <5 min. Recycling active solids permitted EEA despite overloading which was critical to the performance of the RBRs.}, } @article {pmid31846135, year = {2020}, author = {Ben Lagha, A and LeBel, G and Grenier, D}, title = {Tart cherry (Prunus cerasus L.) fractions inhibit biofilm formation and adherence properties of oral pathogens and enhance oral epithelial barrier function.}, journal = {Phytotherapy research : PTR}, volume = {34}, number = {4}, pages = {886-895}, doi = {10.1002/ptr.6574}, pmid = {31846135}, issn = {1099-1573}, support = {2017-2018//Cherry Marketing Institute/ ; }, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects/physiology ; Cells, Cultured ; Chemical Fractionation ; Dental Caries/microbiology ; Fruit/chemistry ; Fusobacterium nucleatum/drug effects/physiology ; Humans ; Mouth/*microbiology ; Mouth Mucosa/*drug effects/metabolism/microbiology/physiology ; Permeability/drug effects ; Plant Extracts/chemistry/*pharmacology ; Prunus/*chemistry ; Streptococcus mutans/drug effects/physiology ; }, abstract = {Dental caries, candidiasis, and periodontal disease are the most common oral infections affecting a wide range of the population worldwide. The present study investigated the effects of two tart cherry (Prunus cerasus L.) fractions on important oral pathogens, including Candida albicans, Streptococcus mutans, and Fusobacterium nucleatum, as well as on the barrier function of oral epithelial cells. Procyanidins and quercetin and its derivatives were the most important constituents found in the tart cherry fractions. Although the fractions showed poor antimicrobial activity, they inhibited biofilm formation by the three oral pathogens in a dose-dependent manner. The tart cherry fractions also attenuated the adherence of C. albicans and S. mutans to a hydroxylapatite surface as well as the adherence of F. nucleatum to oral epithelial cells. Treating oral epithelial cells with the tart cherry fractions significantly enhanced the barrier function as determined by monitoring the transepithelial electrical resistance. In conclusion, this study showed that the tart cherry fractions and their bioactive constituents could be promising antiplaque compounds by targeting biofilm formation and adherence properties of oral pathogens. Furthermore, its property of increasing the epithelial barrier function may protect against microbial invasion of the underlying connective tissue.}, } @article {pmid31842619, year = {2020}, author = {Rocca, DM and Aiassa, V and Zoppi, A and Silvero Compagnucci, J and Becerra, MC}, title = {Nanostructured Gold Coating for Prevention of Biofilm Development in Medical Devices.}, journal = {Journal of endourology}, volume = {34}, number = {3}, pages = {345-351}, doi = {10.1089/end.2019.0686}, pmid = {31842619}, issn = {1557-900X}, mesh = {*Biofilms ; Equipment Design ; Gold/*chemistry ; Humans ; *Infection Control ; Nanoparticles ; *Urinary Catheters ; }, abstract = {Bacterial biofilms on medical devices (MDs) can cause deadly infections due to their resistance to antibiotics. Technology to prevent this kind of complication is urgently needed because they impact not only patients' lives but also hospital budgets. In this article, the creation and testing of an easy-to-produce antibiofilm (more precisely antibiofouling) coating are described for the first time. This coating can be applied to catheters, prostheses, and other plastic pieces, even after they have been manufactured. Rapid and ecofriendly synthesis of nanostructured gold coating was done in situ in just 15 minutes. Complete characterization and microbiological analysis of its antibiofouling capacity are presented. The coating prevents biofilm formation of pathogenic clinical isolates and ATCC strains on MDs, possibly due to its complex nanostructured gold surface. If the next generation of MDs is coated with this kind of antibiofouling technology, biofilm-related infections could be dramatically reduced. Graphical Abstract [Figure: see text].}, } @article {pmid31842508, year = {2019}, author = {Park, SC and Lee, MY and Kim, JY and Kim, H and Jung, M and Shin, MK and Lee, WK and Cheong, GW and Lee, JR and Jang, MK}, title = {Anti-Biofilm Effects of Synthetic Antimicrobial Peptides Against Drug-Resistant Pseudomonas aeruginosa and Staphylococcus aureus Planktonic Cells and Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {24}, pages = {}, pmid = {31842508}, issn = {1420-3049}, support = {NRF-2016R1D1A3A03918533 & NRF-2019R1I1A3A01062547//National Research Foundation of Korea/ ; }, mesh = {*Anti-Infective Agents/chemical synthesis/chemistry/pharmacology ; *Antimicrobial Cationic Peptides/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/*drug effects ; Plankton/*physiology ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; }, abstract = {Biofilm-associated infections are difficult to manage or treat as biofilms or biofilm-embedded bacteria are difficult to eradicate. Antimicrobial peptides have gained increasing attention as a possible alternative to conventional drugs to combat drug-resistant microorganisms because they inhibit the growth of planktonic bacteria by disrupting the cytoplasmic membrane. The current study investigated the effects of synthetic peptides (PS1-2, PS1-5, and PS1-6) and conventional antibiotics on the growth, biofilm formation, and biofilm reduction of drug-resistant Pseudomonas aeruginosa and Staphylococcus aureus. The effects of PS1-2, PS1-5, and PS1-6 were also tested in vivo using a mouse model. All peptides inhibited planktonic cell growth and biofilm formation in a dose-dependent manner. They also reduced preformed biofilm masses by removing the carbohydrates, extracellular DNA, and lipids that comprised extracellular polymeric substances (EPSs) but did not affect proteins. In vivo, PS1-2 showed the greatest efficacy against preformed biofilms with no cytotoxicity. Our findings indicate that the PS1-2 peptide has potential as a next-generation therapeutic drug to overcome multidrug resistance and to regulate inflammatory response in biofilm-associated infections.}, } @article {pmid31841686, year = {2020}, author = {Afrasiabi, S and Pourhajibagher, M and Chiniforush, N and Aminian, M and Bahador, A}, title = {Anti-biofilm and anti-metabolic effects of antimicrobial photodynamic therapy using chlorophyllin-phycocyanin mixture against Streptococcus mutans in experimental biofilm caries model on enamel slabs.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {29}, number = {}, pages = {101620}, doi = {10.1016/j.pdpdt.2019.101620}, pmid = {31841686}, issn = {1873-1597}, mesh = {Biofilms/drug effects ; Chlorophyllides/*pharmacology ; Dental Caries/microbiology ; Dental Enamel/drug effects ; In Vitro Techniques ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Phycocyanin/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {BACKGROUND: Partial (selective) removal of dental caries is a suitable manner to treat deep carious lesions in vital teeth with asymptomatic pulps. Antimicrobial photodynamic therapy (aPDT) was proposed as a promising ancillary approach for reduction of the residual bacteria from the cavity. Therefore, the focus of this study was to investigate the influence of aPDT using diode laser (DL) plus PhotoActive+ (chlorophyllin-phycocyanin mixture [CHL-PC]) as photosensitizer (PS) on metabolic activity and the reduction in the number of living bacteria within the preformed biofilm caries model on enamel slabs of Streptococcus mutans.

MATERIALS AND METHODS: The lethal and sub-significant inhibitory (SSI) potential of aPDT using CHL-PC and 635 nm DL against experimental biofilm caries model on enamel slabs and metabolic activity of S. mutans was analyzed using crystal violet and XTT reduction assays, respectively. Intracellular ROS formation by DCFH-DA assay was measured in CHL-PC mediated aPDT treated bacterial samples. Tooth discoloration and cell cytotoxicity of CHL-PC were assessed in the CIEL*a*b* color space and neutral red assay, respectively.

RESULTS: In this study aPDT at a maximum concentration level of CHL-PC (5000 μg/mL) with 3 min DL irradiation time (103.12 J/cm[2]) reduced the ex-vivo cariogenic biofilm of S. mutans by 36.93 % (P <  0.05). Although chlorhexidine (CHX) had an anti-biofilm effect about 1.7 fold compared to CHL-PC mediated aPDT, this difference was not significant (36.93 in comparison to 63.05 %; P >  0.05). CHL-PC mediated aPDT demonstrated a significant reduction in bacterial metabolic activity, with rates of 77 % at a SSI dose (using 156 μg/mL of CHL-PC and 3 min DL irradiation time with the energy density of 103.12 J/cm[2]). The treated bacterial cells exhibited significant (P < 0.05) increment in the ROS generation. The least color change (ΔE) was found using CHL-PC at a concentration of 156 μg/mL (ΔE = 2.74). CHL-PC in different concentrations showed no significant reduction in human gingival fibroblasts (HGFs) cell survival (P >  0.05).

CONCLUSION: CHL-PC mediated aPDT not only reduces the number of living bacteria within the biofilms of S. mutans in an experimental biofilm caries model on enamel slabs but also its influences microbial virulence by reducing the metabolic activity of the S. mutants.}, } @article {pmid31839202, year = {2020}, author = {Chen, H and Tang, Y and Weir, MD and Gao, J and Imazato, S and Oates, TW and Lei, L and Wang, S and Hu, T and Xu, HHK}, title = {Effects of S. mutans gene-modification and antibacterial monomer dimethylaminohexadecyl methacrylate on biofilm growth and acid production.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {36}, number = {2}, pages = {296-309}, doi = {10.1016/j.dental.2019.12.001}, pmid = {31839202}, issn = {1879-0097}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Methacrylates ; Microbial Sensitivity Tests ; *Streptococcus mutans ; }, abstract = {OBJECTIVES: Antibacterial quaternary ammonium monomers (QAMs) are used in resins. The rnc gene in Streptococcus mutans (S. mutans) plays a key role in resisting antibiotics. The objectives of this study were to investigate for the first time: (1) the effects of rnc deletion on S. mutans biofilms and acid production; (2) the combined effects of rnc deletion with dimethylaminohexadecyl methacrylate (DMAHDM) on biofilm-inhibition efficacy.

METHODS: Parent S. mutans strain UA159 (ATCC 700610) and the rnc-deleted S. mutans were used. Bacterial growth, minimum inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) were measured to analyze the bacterial susceptibility of the parent and rnc-deleted S. mutans against DMAHDM, with the gold-standard chlorhexidine (CHX) as control. Biofilm biomass, polysaccharide and lactic acid production were measured.

RESULTS: The drug-susceptibility of the rnc-deleted S. mutans to DMAHDM or CHX was 2-fold higher than parent S. mutans. The drug-susceptibility did not increase after 10 passages (p < 0.05). Deleting the rnc gene increased the biofilm susceptibility to DMAHDM or CHX by 2-fold. The rnc-deletion in S. mutans reduced biofilm biomass, polysaccharide and lactic acid production, even at no drugs. DMAHDM was nearly 40 % more potent than the gold-standard CHX. The combination of rnc deletion+DMAHDM treatment achieved the greatest reduction in biofilm biomass, polysaccharide synthesis, and lactic acid production.

SIGNIFICANCE: Gene modification by deleting the rnc in S. mutans reduced the biofilm growth and acid production, and the rnc deletion+DMAHDM method showed the greatest biofilm-inhibition efficacy, for the first time. The dual strategy of antibacterial monomer+bacterial gene modification shows great potential to control biofilms and inhibit caries.}, } @article {pmid31838704, year = {2020}, author = {Voisin, J and Cournoyer, B and Marjolet, L and Vienney, A and Mermillod-Blondin, F}, title = {Ecological assessment of groundwater ecosystems disturbed by recharge systems using organic matter quality, biofilm characteristics, and bacterial diversity.}, journal = {Environmental science and pollution research international}, volume = {27}, number = {3}, pages = {3295-3308}, pmid = {31838704}, issn = {1614-7499}, support = {ANR-16-CE32-0006 FROG//Agence Nationale de la Recherche/ ; EST 2016/1/120//Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail/ ; PhD grant//Région Auvergne-Rhône-Alpes/ ; OTHU//Agence de l'Eau Rhône Méditerranée Corse/ ; OTHU//Métropole de Lyon/ ; }, mesh = {Bacteria/*chemistry ; Biofilms ; *Ecosystem ; *Groundwater ; RNA, Ribosomal, 16S/*chemistry ; }, abstract = {Recharge of aquifers by urban stormwater may trigger significant ecological changes that can be detrimental to the biodiversity and functioning of groundwater ecosystems. Here, the effects of aquifer recharge (AR) on three levels of parameters were investigated: dissolved organic carbon (DOC) quantity and quality, global biofilm characteristics, and diversity changes of bacterial communities. As DOC enrichment by AR can be mitigated by vadose zone (VZ) thickness, three AR sites with thin VZ (< 3 m) and three sites with thick VZ (> 10 m) were selected. For each AR site, clay beads were incubated over a 10-day-long rainy period through wells in recharged and non-recharged groundwaters. Total proteins, dehydrogenase, and hydrolytic activities were monitored from clay beads to assess biofilm development. Bacterial richness on beads was estimated by 16S rRNA-based metabarcoding. AR was found to significantly increase DOC and biodegradable DOC (BDOC) concentrations, biofilm development, and bacterial richness especially in sites with thin VZ. VZ thickness was inversely related to microbial growth indicators and bacterial richness in groundwater, through a control of DOC availability. The proportion of Bacteroidetes 16S rRNA gene reads was higher in recharged groundwater than in non-recharged groundwater, suggesting that this phylum could be used as an indicator of DOC enrichment associated with AR. Quantitative PCR assays for Bacteroides DNA confirmed these trends and showed an enrichment of this bacterial group in DOC-rich aquifer waters. The positive linear relationships between BDOC concentrations and biofilm variables highlighted a strong C-limitation of groundwater impacting bacterial species sorting and activity.}, } @article {pmid31835971, year = {2019}, author = {Magalhães, AP and Jorge, P and Pereira, MO}, title = {Pseudomonas aeruginosa and Staphylococcus aureus communication in biofilm infections: insights through network and database construction.}, journal = {Critical reviews in microbiology}, volume = {45}, number = {5-6}, pages = {712-728}, doi = {10.1080/1040841X.2019.1700209}, pmid = {31835971}, issn = {1549-7828}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Databases, Factual ; Humans ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/drug effects/genetics/*physiology ; Quorum Sensing/drug effects ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus aureus/drug effects/genetics/*physiology ; }, abstract = {The polymicrobial nature of most infections is often characterized by complex biofilm communities, where pathogen interactions promote infection progression and severity. Quorum-sensing, the major regulator of virulence and inter-species communication, is a promising target for new anti-infective strategies. This study aimed at collecting and analysing experimental information on the molecular basis of Pseudomonas aeruginosa and Staphylococcus aureus interactions in biofilms. Data were systematically annotated from relevant full-text papers optimally retrieved from PubMed, reconstructed as networks and integrated with specialized databases to identify promising antimicrobial targets. Network analysis revealed key entities regulating P. aeruginosa/S. aureus interactions, for instance the PqsABCDE/PqsR quorum-sensing system, which affects S. aureus growth and biofilm formation. By identifying the most reported P. aeruginosa virulence factors affecting S. aureus, for example, HQNO and siderophores, a list of experimentally validated agents affecting those factors, ranging from synthetic drugs to natural plant extracts, was constructed. The complex experimental data on P. aeruginosa/S. aureus interactions were for the first time systematically organized and made publically available in the new Inter-Species CrossTalk Database (www.ceb.uminho.pt/ISCTD).}, } @article {pmid31835833, year = {2019}, author = {Felix Gomez, GG and Lippert, F and Ando, M and Zandona, AF and Eckert, GJ and Gregory, RL}, title = {Photoinhibition of Streptococcus mutans Biofilm-Induced Lesions in Human Dentin by Violet-Blue Light.}, journal = {Dentistry journal}, volume = {7}, number = {4}, pages = {}, pmid = {31835833}, issn = {2304-6767}, abstract = {This in vitro study determined the effectiveness of violet-blue light on Streptococcus mutans (UA159) biofilm induced dentinal lesions. Biofilm was formed on human dentin specimens in a 96-well microtiter plate and incubated for 13 h in the presence of tryptic soy broth (TSB) or TSB supplemented with 1% sucrose (TSBS). Violet-blue light (405 nm) from quantitative light-induced fluorescence (QLF[TM]) was used to irradiate the biofilm. Supernatant liquid was removed, and the biofilm was irradiated continuously with QLF for 5 min twice daily with an interval of 6 h for 5 d, except with one treatment on the final day. Colony forming units (CFU) of the treated biofilm, changes in fluorescence (∆F; QLF-Digital Biluminator[TM]), lesion depth (L), and integrated mineral loss (∆Z; both transverse microradiography) were quantified at the end of the fifth day. Statistical analysis used analysis of variance (ANOVA), testing at a 5% significance level. In the violet-blue light irradiated groups, there was a significant reduction (p < 0.05) of bacterial viability (CFU) of S. mutans with TSB and TSBS. Violet-blue light irradiation resulted in the reduction of ∆F and L of the dentinal surface with TSBS. These results indicate that violet-blue light has the capacity to reduce S. mutans cell numbers.}, } @article {pmid31835470, year = {2019}, author = {Di Onofrio, V and Gesuele, R and Maione, A and Liguori, G and Liguori, R and Guida, M and Nigro, R and Galdiero, E}, title = {Prevention of Pseudomonas aeruginosa Biofilm Formation on Soft Contact Lenses by Allium sativum Fermented Extract (BGE) and Cannabinol Oil Extract (CBD).}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31835470}, issn = {2079-6382}, abstract = {Two natural mixtures, Allium sativum fermented extract (BGE) and cannabinol oil extract (CBD), were assessed for their ability to inhibit and remove Pseudomonas aeruginosa biofilms on soft contact lenses in comparison to a multipurpose Soft Contact Lens-care solution present on the Italian market. Pseudomonas aeruginosa (ATCC 9027 strain) and Pseudomonas aeruginosa clinical strains isolated from ocular swabs were tested. Quantification of the biofilm was done using the microtiter plate assay and the fractional inhibitory concentration index was calculated. Both forms of Pseudomonas aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) showed inhibition percentages higher than 55% for both strains, and CBD inhibited biofilm formation by about 70%. The care solution at MIC inhibited biofilm formation by about 50% for both strains tested. The effect of BGE on the eradication of the microbial biofilm on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and 36% for P. aeruginosa clinical strain. For CBD, we observed 24% biofilm eradication for both strains. For the care solution, the eradication MICs were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain. It was observed that both the test soft contact lenses solution/BGE (fractional inhibitory concentration index: 0.450) and the test soft contact lenses solution/CBD (fractional inhibitory concentration index: 0.153) combinations exhibited synergistic antibiofilm activity against most of the studied bacteria. The study showed that BGE and CBD have good effect on inhibition of biofilm formation and removal of preformed biofilms, which makes them promising agents that could be exploited to develop more effective care solutions.}, } @article {pmid31835290, year = {2019}, author = {De la Cruz-Claure, ML and Cèspedes-Llave, AA and Ulloa, MT and Benito-Lama, M and Domínguez-Álvarez, E and Bastida, A}, title = {Inhibition-Disruption of Candida glabrata Biofilms: Symmetrical Selenoesters as Potential Anti-Biofilm Agents.}, journal = {Microorganisms}, volume = {7}, number = {12}, pages = {}, pmid = {31835290}, issn = {2076-2607}, support = {COOPB20237//Consejo Superior de Investigaciones Científicas/ ; 201780I027//Consejo Superior de Investigaciones Científicas/ ; }, abstract = {Candida glabrata is one of the most prevalent pathogenic Candida species in dental plaque on tooth surfaces. Candida biofilms exhibit an enhanced resistance against most antifungal agents. Thus, the development of alternative more potent and effective antimicrobials is required to overcome this resistance. In this study, three novel fluorinated derivatives and nine selenoester compounds were screened as novel antifungal and antibiofilm agents against C. krusei, C. parapsilosis, and C. glabrata (N = 81 dental isolates). C. glabrata strains were susceptible only to fluorinated compounds while C. krusei, C. parapsilosis, and C. glabrata were susceptible to the action of the selenoesters. The evaluated symmetrical selenoester compounds presented very good antifungal activity against all the tested C. glabrata dental isolates (1-4 μg/mL of minimum inhibitory concentration-MIC). The most active compound (Se-5) was able to inhibit and disperse C. glabrata biofilms. These results demonstrated that selenoesters may be novel and promising biocide agents against C. glabrata clinical dental isolates.}, } @article {pmid31835130, year = {2020}, author = {Laureni, M and Weissbrodt, DG and Villez, K and Robin, O and de Jonge, N and Rosenthal, A and Wells, G and Nielsen, JL and Morgenroth, E and Joss, A}, title = {Erratum to "Biomass segregation between biofilm and flocs improves the control of nitrite-oxidizing bacteria in mainstream partial nitritation and anammox processes" [Water Res. 154 (2019) 104-116].}, journal = {Water research}, volume = {169}, number = {}, pages = {115133}, doi = {10.1016/j.watres.2019.115133}, pmid = {31835130}, issn = {1879-2448}, } @article {pmid31834677, year = {2020}, author = {Yang, C and Mavelli, GV and Nacharaju, P and Li, K and Cleare, LG and Nosanchuk, JD and Friedman, JM and Abuzeid, WM}, title = {Novel nitric oxide-generating platform using manuka honey as an anti-biofilm strategy in chronic rhinosinusitis.}, journal = {International forum of allergy & rhinology}, volume = {10}, number = {2}, pages = {223-232}, doi = {10.1002/alr.22472}, pmid = {31834677}, issn = {2042-6984}, support = {P30CA013330/BC/NCI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/drug effects ; Chronic Disease ; *Honey ; Nitric Oxide/*chemistry ; Nitrites/*administration & dosage/chemistry ; Organosilicon Compounds/*administration & dosage/chemistry ; Oxidation-Reduction ; Pseudomonas aeruginosa/*drug effects/physiology ; Rhinitis/therapy ; Sinusitis/therapy ; }, abstract = {BACKGROUND: Bacterial biofilms are implicated in the pathogenesis of chronic rhinosinusitis. Nitric oxide (NO) is a key immune effector with potent antimicrobial effects, but a short half-life limits achievement of therapeutic concentrations. We hypothesized that manuka honey (MH) could induce sustained reduction of nitrite to NO causing biofilm disruption and that this effect would be enhanced with the addition of a NO-releasing microparticle.

METHODS: Porous organosilica microparticles containing nitrosylated thiol groups were formulated (SNO-MP). MH was combined with serial dilutions of nitrite. NO release was evaluated using a NO analyzer. The susceptibility of 2 strains of Pseudomonas aeruginosa biofilms to these NO-releasing platforms was evaluated using confocal microscopy. Cell viability and biofilm volume were quantified. Statistical analysis was performed using the Mann-Whitney U test with SPSS software.

RESULTS: MH with nitrite generated a linear increase in NO formation. SNO-MP induced a bolus release of NO within 5 minutes, followed by a sustained plateau phase. MH with nitrite combined with SNO-MP enhanced NO release during the plateau phase. MH with nitrite reduced biofilm live cells and volume by 88.5% to 96.9% and 95.1% to 95.6%, respectively, vs control (p < 0.0001). SNO-MP reduced live cells and volume by 61.0% to 98.5% and 74.7% to 85.7%, respectively, vs control (p < 0.0001). MH with nitrite combined with SNO-MP nearly eradicated biofilm, with a 98.3% to 99.8% (log 1.8-2.6) reduction in viability and a 91.4% to 97.7% decrease in volume (p < 0.0001 vs control).

CONCLUSION: A novel platform that generates NO using MH and nitrite produces a potent anti-biofilm effect, which can be further enhanced with the addition of SNO-MP.}, } @article {pmid31834370, year = {2019}, author = {Ogasawara, H and Ishizuka, T and Yamaji, K and Kato, Y and Shimada, T and Ishihama, A}, title = {Regulatory role of pyruvate-sensing BtsSR in biofilm formation by Escherichia coli K-12.}, journal = {FEMS microbiology letters}, volume = {366}, number = {24}, pages = {}, doi = {10.1093/femsle/fnz251}, pmid = {31834370}, issn = {1574-6968}, mesh = {Biofilms/*growth & development ; Escherichia coli K12/genetics/*growth & development/*metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/genetics/physiology ; Promoter Regions, Genetic/genetics ; Pyruvic Acid/*metabolism ; Transcription Factors/genetics/metabolism ; }, abstract = {Pyruvate, the key regulator in connection of a variety of metabolic pathways, influences transcription of the Escherichia coli genome through controlling the activity of two pyruvate-sensing two-component systems (TCSs), BtsSR and PyrSR. Previously, we identified the whole set of regulatory targets of PyrSR with low-affinity to pyruvate. Using gSELEX screening system, we found here that BtsSR with high-affinity to pyruvate regulates more than 100 genes including as many as 13 transcription factors genes including the csgD gene encoding the master regulator of biofilm formation. CsgD regulates more than 20 target genes including the csg operons encoding the Curli fimbriae. In addition, we identified the csgBAC as one of the regulatory targets of BtsR, thus indicating the involvement of two pyruvate-dependent regulatory pathways of the curli formation: indirect regulation by CsgD; and direct regulation by BtsR. Based on the findings of the whole set of regulatory targets by two pyruvate-sensing BtsR and PyrR, we further propose an innovative concept that the pyruvate level-dependent regulation of different gene sets takes place through two pyruvate-sensing TCS systems, high-affinity BtsSR and low-affinity PyrSR to pyruvate.}, } @article {pmid31833386, year = {2020}, author = {Hassan, PA and Khider, AK}, title = {Correlation of biofilm formation and antibiotic resistance among clinical and soil isolates of Acinetobacter baumannii in Iraq.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {67}, number = {3}, pages = {161-170}, doi = {10.1556/030.66.2019.026}, pmid = {31833386}, issn = {1588-2640}, mesh = {Acinetobacter Infections/*epidemiology/*microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacteriological Techniques ; Biofilms/*drug effects ; DNA, Bacterial ; *Drug Resistance, Multiple, Bacterial ; Humans ; Iraq/epidemiology ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Soil Microbiology ; beta-Lactamases/genetics ; }, abstract = {Acinetobacter baumannii is an opportunistic pathogen that is reported as a major cause of nosocomial infections. The aim of this study was to investigate the biofilm formation by A. baumannii clinical and soil isolates, to display their susceptibility to 11 antibiotics and to study a possible relationship between formation of biofilm and multidrug resistance. During 8 months period, from June 2016 to January 2017, a total of 52 clinical and 22 soil isolates of A. baumannii were collected and identified through conventional phenotypic, chromo agar, biochemical tests, API 20E system, and confirmed genotypically by PCR for blaOXA-51-like gene. Antibiotic susceptibility of isolates was determined by standard disk diffusion method according to Clinical and Laboratory Standard Institute. The biofilm formation was studied using Congo red agar, test tube, and microtiter plate methods. The clinical isolates were 100% resistance to ciprofloxacin, ceftazidime, piperacillin, 96.15% to gentamicin, 96.15% to imipenem, 92.31% to meropenem, and 78.85% to amikacin. The soil A. baumannii isolates were 100% sensitive to imipenem, meropenem, and gentamicin, and 90.1% to ciprofloxacin. All A. baumannii isolates (clinical and soil) were susceptible to polymyxin B. The percentage of biofilm formation in Congo red agar, test tube, and microtiter plate assays was 10.81%, 63.51%, and 86.48%, respectively. More robust biofilm former population was mainly among non-MDR isolates. Isolates with a higher level of resistance tended to form weaker biofilms. The soil isolates exhibited less resistance to antibiotics than clinical isolates. However, the soil isolates produce stronger biofilms than clinical isolates.}, } @article {pmid31833369, year = {2020}, author = {Afzal, M and Saccenti, E and Madsen, MB and Hansen, MB and Hyldegaard, O and Skrede, S and Martins Dos Santos, VAP and Norrby-Teglund, A and Svensson, M}, title = {Integrated Univariate, Multivariate, and Correlation-Based Network Analyses Reveal Metabolite-Specific Effects on Bacterial Growth and Biofilm Formation in Necrotizing Soft Tissue Infections.}, journal = {Journal of proteome research}, volume = {19}, number = {2}, pages = {688-698}, doi = {10.1021/acs.jproteome.9b00565}, pmid = {31833369}, issn = {1535-3907}, mesh = {Biofilms ; *Fasciitis, Necrotizing ; Humans ; Risk Factors ; *Soft Tissue Infections/diagnosis ; Streptococcus pyogenes ; }, abstract = {Necrotizing soft-tissue infections (NSTIs) have multiple causes, risk factors, anatomical locations, and pathogenic mechanisms. In patients with NSTI, circulating metabolites may serve as a substrate having impact on bacterial adaptation at the site of infection. Metabolic signatures associated with NSTI may reveal the potential to be useful as diagnostic and prognostic markers and novel targets for therapy. This study used untargeted metabolomics analyses of plasma from NSTI patients (n = 34) and healthy (noninfected) controls (n = 24) to identify the metabolic signatures and connectivity patterns among metabolites associated with NSTI. Metabolite-metabolite association networks were employed to compare the metabolic profiles of NSTI patients and noninfected surgical controls. Out of 97 metabolites detected, the abundance of 33 was significantly altered in NSTI patients. Analysis of metabolite-metabolite association networks showed a more densely connected network: specifically, 20 metabolites differentially connected between NSTI and controls. A selected set of significantly altered metabolites was tested in vitro to investigate potential influence on NSTI group A streptococcal strain growth and biofilm formation. Using chemically defined media supplemented with the selected metabolites, ornithine, ribose, urea, and glucuronic acid, revealed metabolite-specific effects on both bacterial growth and biofilm formation. This study identifies for the first time an NSTI-specific metabolic signature with implications for optimized diagnostics and therapies.}, } @article {pmid31833296, year = {2019}, author = {Han, H and Liu, ZY and Guo, JJ and Fu, XL and He, J and Guo, YD and Cai, JF}, title = {Prospects of Application of Microbial Biofilm to Estimate PMI of Corpses in Water.}, journal = {Fa yi xue za zhi}, volume = {35}, number = {5}, pages = {596-601}, doi = {10.12116/j.issn.1004-5619.2019.05.016}, pmid = {31833296}, issn = {1004-5619}, mesh = {*Autopsy ; *Biofilms ; Cadaver ; *Drowning ; Forensic Pathology/*methods ; Humans ; *Postmortem Changes ; Water ; }, abstract = {In forensic pathology, the estimation of postmortem interval （PMI） has always been a difficult issue, and there is still lack of effective methods to estimate PMI of corpses in water. Microbial biofilm refers to the microbial population attached to non-biological or biological surfaces by microorganisms during microbial growth, that has a three-dimensional structure, surrounded by extracellular polymers and matrix networks created by itself. A series of community succession phenomena of microorganisms occur during the occurrence and development of microbial population. The microbial community and its succession process of this kind of biofilm attached to the surface of a corpse in water may become a new basis for estimation of the PMI of corpses in water. This review elucidates on the concept, classification, research methods, and influencing factors of biofilm and analyzes its application prospects in PMI estimation of corpses in water, which would provide new ideas for the researches in this field.}, } @article {pmid31831165, year = {2020}, author = {Acosta, LD and Pérez-Camacho, O and Acosta, R and Escobar, DM and Gallardo, CA and Sánchez-Vargas, LO}, title = {Reduction of Candida albicans biofilm formation by coating polymethyl methacrylate denture bases with a photopolymerized film.}, journal = {The Journal of prosthetic dentistry}, volume = {124}, number = {5}, pages = {605-613}, doi = {10.1016/j.prosdent.2019.08.003}, pmid = {31831165}, issn = {1097-6841}, mesh = {Biofilms ; *Candida albicans ; Denture Bases ; Humans ; Materials Testing ; *Polymethyl Methacrylate ; Surface Properties ; }, abstract = {STATEMENT OF PROBLEM: As Candida albicans biofilm formation is associated with severe local and systemic infections in denture-wearing patients, its prevention or reduction becomes an essential factor in the health of this population.

PURPOSE: The purpose of this in vitro study was to investigate whether 2 photopolymerized coatings of poly(acrylic acid) (PAA) and poly(itaconic acid) (PIA) can effectively reduce the adhesion of C albicans on denture base acrylic resin surfaces.

MATERIAL AND METHODS: The surface of the polymethyl methacrylate (PMMA) denture base was modified through photopolymerization of a thin film of PAA or PIA. The polymeric coatings were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), contact angle goniometry (CA), and surface roughness measurement (Ra). For biological evaluation, the coated PMMA surfaces were tested in a C albicans biofilm dynamic formation model, observed by confocal laser scanning microscopy (CLSM), and quantified by the number of colony-forming units (CFUs). The cytotoxicity of the polymeric coatings was also evaluated by using a lactic dehydrogenase-based (LDH) test. For statistical analysis, ANOVA and the nonparametric Kruskal-Wallis test were used (α=.05).

RESULTS: The PMMA resin base surfaces coated with PAA and PIA had an inhibitory effect on C albicans growth, the wettability of the coated surface, and the average roughness. The PAA and PIA coatings had no statistically significant cytotoxic effect on periodontal ligament fibroblasts.

CONCLUSIONS: PMMA acrylic resin base material was superficially modified through the incorporation of carboxylic acid groups by using PAA and PIA coatings that reduced the adherence of C albicans biofilm by 90%.}, } @article {pmid31830915, year = {2019}, author = {Banar, M and Emaneini, M and Beigverdi, R and Fanaei Pirlar, R and Node Farahani, N and van Leeuwen, WB and Jabalameli, F}, title = {The efficacy of lyticase and β-glucosidase enzymes on biofilm degradation of Pseudomonas aeruginosa strains with different gene profiles.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {291}, pmid = {31830915}, issn = {1471-2180}, mesh = {A549 Cells ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Burns/microbiology ; Cell Line, Tumor ; Cell Survival/drug effects ; Cystic Fibrosis/microbiology ; Glucan Endo-1,3-beta-D-Glucosidase/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Multienzyme Complexes/*pharmacology ; Peptide Hydrolases/*pharmacology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/*genetics ; beta-Glucosidase/*pharmacology ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is a nosocomial pathogen that causes severe infections in immunocompromised patients. Biofilm plays a significant role in the resistance of this bacterium and complicates the treatment of its infections. In this study, the effect of lyticase and β-glucosidase enzymes on the degradation of biofilms of P. aeruginosa strains isolated from cystic fibrosis and burn wound infections were assessed. Moreover, the decrease of ceftazidime minimum biofilm eliminating concentrations (MBEC) after enzymatic treatment was evaluated.

RESULTS: This study demonstrated the effectiveness of both enzymes in degrading the biofilms of P. aeruginosa. In contrast to the lyticase enzyme, β-glucosidase reduced the ceftazidime MBECs significantly (P < 0.05). Both enzymes had no cytotoxic effect on the A-549 human lung carcinoma epithelial cell lines and A-431 human epidermoid carcinoma cell lines.

CONCLUSION: Considering the characteristics of the β-glucosidase enzyme, which includes the notable degradation of P. aeruginosa biofilms and a significant decrease in the ceftazidime MBECs and non-toxicity for eukaryotic cells, this enzyme can be a promising therapeutic candidate for degradation of biofilms in burn wound patients, but further studies are needed.}, } @article {pmid31830536, year = {2020}, author = {Cao, Y and Naseri, M and He, Y and Xu, C and Walsh, LJ and Ziora, ZM}, title = {Non-antibiotic antimicrobial agents to combat biofilm-forming bacteria.}, journal = {Journal of global antimicrobial resistance}, volume = {21}, number = {}, pages = {445-451}, doi = {10.1016/j.jgar.2019.11.012}, pmid = {31830536}, issn = {2213-7173}, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial ; Food Microbiology ; Metal Nanoparticles/chemistry ; }, abstract = {Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bacteria in biofilms are less susceptible to antibiotics compared with their free-floating state, as biofilms impair antibiotic penetration. To obviate this challenge, non-antibiotic antimicrobial agents are needed. This review describes two classes of these agents, namely antimicrobial nanoparticles and antimicrobial peptides. Applications of these antimicrobials in the food industry and medical applications are discussed, and the directions for future research are highlighted.}, } @article {pmid31828607, year = {2020}, author = {Berkes, E and Liao, YH and Neef, D and Grandalski, M and Monsul, N}, title = {Potentiated In Vitro Probiotic Activities of Lactobacillus fermentum LfQi6 Biofilm Biomass Versus Planktonic Culture.}, journal = {Probiotics and antimicrobial proteins}, volume = {12}, number = {3}, pages = {1097-1114}, pmid = {31828607}, issn = {1867-1314}, mesh = {*Antibiosis ; Biofilms/growth & development ; Caco-2 Cells ; Humans ; *Limosilactobacillus fermentum/growth & development/metabolism ; *Probiotics ; }, abstract = {In this study, we describe enhanced in vitro probiotic activities of preformed biofilms versus planktonic cultures of Lactobacillus fermentum LfQi6 (LfQi6), a lactic acid bacterium (LAB) isolated from the human microbiome. These evaluations are used to help predict host in vivo probiotic benefits and therefore indicate that LfQi6 may provide significant probiotic benefits in the human host when administered as preformed biofilms rather than as planktonic cultures. Specifically, LfQi6 biofilms demonstrated improved in vitro performance versus LfQi6 planktonic cultures for host gastrointestinal survival and engraftment, strain-specific antimicrobial and anti-biofilm activity against clinically significant pathogens, concurrent promotion of beneficial gastrointestinal commensal biofilms, beneficial commensal enzyme activities, and host cellular-protective glutathione antioxidant activity. Evaluation of LfQi6 according to the European Food Safety Authority (EFSA 2007, 2012, 2015) Guidelines and Joint FAO/WHO Expert Consultation on Evaluation of Health and Nutritional Properties of Probiotics in Food Evaluation of Probiotics in Food (FAO/WHO, 2002) demonstrates strain safety. In summary, in vitro evaluation of Lact. fermentum LfQi6 demonstrates significant evidence for strain-specific probiotic characteristics and safety. Moreover, strain-specific as well as biofilm-phenotype-specific benefits demonstrated in vitro furthermore suggest that in vivo use of LfQi6 biofilm biomass may be of greater benefit to the human host than the use of standard planktonic cultures. This concept - potentiating probiotic benefits through the use of preformed commensal biofilms - is novel and may serve to further broaden the application of microbial biofilms to human health.}, } @article {pmid31827464, year = {2019}, author = {Bansal, M and Nannapaneni, R and Kode, D and Chang, S and Sharma, CS and McDaniel, C and Kiess, A}, title = {Rugose Morphotype in Salmonella Typhimurium and Salmonella Heidelberg Induced by Sequential Exposure to Subinhibitory Sodium Hypochlorite Aids in Biofilm Tolerance to Lethal Sodium Hypochlorite on Polystyrene and Stainless Steel Surfaces.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2704}, pmid = {31827464}, issn = {1664-302X}, abstract = {Salmonella biofilms act as a continuous source for cross-contamination in the food processing environments. In this study, a stable rugose morphotype of Salmonella was first induced by sequential exposure to subinhibitory concentrations (SICs) of sodium hypochlorite (NaOCl) (ranging from 50 to 300 ppm over 18-day period) in tryptic soy broth. Then, rugose and smooth morphotypes of Salmonella Typhimurium ATCC 14028 and Salmonella Heidelberg ATCC 8326 were characterized for biofilm forming abilities on polystyrene and stainless steel surfaces. Rugose morphotype of both ATCC 14028 and ATCC 8326 exhibited higher Exopolysaccharide (EPS) formation than smooth morphotype (p ≤ 0.05). Also, the SICs of NaOCl (200 or 300 ppm in broth model) increased the biofilm formation ability of rugose morphotype of ATCC 8326 (p ≤ 0.05) but decreased that of ATCC 14028. The 2-day-old Salmonella biofilms were treated with biocidal concentrations of 50, 100, or 200 ppm NaOCl (pH 6.15) in water for 5, 10, or 20 min at room temperature. The biofilm reduction in CFU/cm[2] for the rugose was lower than the smooth morphotype on both surfaces (p ≤ 0.05) by lethal NaOCl in water. Scanning electron micrographs on both polystyrene and stainless steel surfaces demonstrated that the rugose morphotype produced a denser biofilm than the smooth morphotype. Transmission electron micrographs revealed the cell wall roughness in rugose morphotype, which may help in tolerance to NaOCl. The gene expression data indicate that the expression of biofilm regulator (csgD), curli (csgA, csgB, and csgC), and cellulose (bcsE) was significantly increased in rugose morphotype when induced by sequential exposure of NaOCl SICs. These findings reveal that the rugose morphotype of S. Typhimurium and S. Heidelberg produced significantly denser biofilm on food contact surfaces, which also increased with sequential exposure to SICs of NaOCl in the case of S. Heidelberg, and these biofilms were more tolerant to biocidal NaOCl concentrations commonly used in the food processing plants.}, } @article {pmid31827056, year = {2020}, author = {Wu, S and Liu, Y and Zhang, H and Lei, L}, title = {Nano-graphene oxide with antisense vicR RNA reduced exopolysaccharide synthesis and biofilm aggregation for Streptococcus mutans.}, journal = {Dental materials journal}, volume = {39}, number = {2}, pages = {278-286}, doi = {10.4012/dmj.2019-039}, pmid = {31827056}, issn = {1881-1361}, mesh = {Biofilms ; *Dental Caries ; *Graphite ; Humans ; RNA, Antisense ; Streptococcus mutans ; }, abstract = {Streptococcus mutans (S. mutans) has been proved to crucial cariogenic pathogens. Antisense vicR RNA reduced the transcription of virulence genes and lead to a reduction in biofilm formation. In the current study, a graphene-oxide plasmid transformation system was developed using interacted GO-polyethylenimine (PEI) complexes loaded with antisense vicR-expressing plasmid (GO-PEI-ASvicR). The particle size distribution and zeta potential of the GO-PEI-based ASvicR were evaluated. Quantitative real-time PCR assays were used to investigate the expression of S. mutans virulence genes. The exopolysaccharide (EPS) production in biofilm were evaluated by confocal laser scanning microscopy and anthrone method. We showed that GO-PEI could efficiently deliver the ASvicR-expressing plasmid into S. mutans cells and support excellent transcripts of ASvicR. Furthermore, GO-PEI-ASvicR significantly reduced virulent-associated gene expressions, suppressed biofilm aggregation and inhibited EPS accumulation. Our reports demonstrated that preserving nano-graphene oxide with antisense vicR RNA will be a more effective strategy for dental caries management.}, } @article {pmid31825276, year = {2020}, author = {Nguyen, TK and Argudín, MA and Deplano, A and Nhung, PH and Nguyen, HA and Tulkens, PM and Dodemont, M and Van Bambeke, F}, title = {Antibiotic Resistance, Biofilm Formation, and Intracellular Survival As Possible Determinants of Persistent or Recurrent Infections by Staphylococcus aureus in a Vietnamese Tertiary Hospital: Focus on Bacterial Response to Moxifloxacin.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {26}, number = {6}, pages = {537-544}, doi = {10.1089/mdr.2019.0282}, pmid = {31825276}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; DNA-Binding Proteins/genetics ; Drug Resistance, Bacterial/*drug effects/genetics ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Genes, Bacterial/drug effects/genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Moxifloxacin/*pharmacology ; Phagocytes/*drug effects ; Reinfection/drug therapy ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/genetics ; Tertiary Care Centers ; Vietnam ; }, abstract = {Resistance is notoriously high in Asia but may not entirely explain therapeutic failures. Specific modes of bacterial life, such as biofilm or intracellular survival, may also contribute to the persistent and/or recurrent character of infections. Most Staphylococcus aureus isolates form biofilm and many survive and even thrive intracellularly. We collected 36 nonduplicate S. aureus isolates (including 18 methicillin-resistant S. aureus) from patients with clinical evidence of persistent or recurrent infections in a large tertiary Vietnamese hospital. We examined their antibiotic resistance profile (minimal inhibitory concentration determination) and clonal relatedness (spa and agr typing, pulsed field gel electrophoresis profiles). We then assessed the activity of moxifloxacin in both biofilms and infected phagocytes (moxifloxacin previously proved to be one of the most active antibiotics against reference strains in these models). spa-types t189 and t437 and agr group I were the most frequent. Among the 36 isolates, 30 were multidrug resistant but 30 were recovered from patients having received an active drug. All tested isolates produced biofilm and survived inside phagocytes. At its human Cmax, moxifloxacin was inactive on biofilms made by moxifloxacin-susceptible as well as moxifloxacin-resistant isolates. It caused only a modest intracellular colony-forming unit decrease against moxifloxacin-susceptible isolates and was inactive against those resistant to moxifloxacin. While our data confirm for this collection the high resistance levels and prevalence of endemic spa- or agr- types in Asia, they show that tolerance in both biofilm and phagocytes are correlated and markedly limit moxifloxacin activity, which goes in line with the suggested role of these modes of life in persistence or recurrence of infections.}, } @article {pmid31825257, year = {2019}, author = {Narendrakumar, L and Theresa, M and Krishnankutty Chandrika, S and Thomas, S}, title = {Tryptanthrin, a potential biofilm inhibitor against toxigenic Vibrio cholerae, modulating the global quorum sensing regulator, LuxO.}, journal = {Biofouling}, volume = {35}, number = {10}, pages = {1093-1103}, doi = {10.1080/08927014.2019.1696315}, pmid = {31825257}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology/toxicity ; Bacterial Proteins/chemistry/*physiology ; Biofilms/*drug effects/growth & development ; Cell Survival ; Cholera/microbiology/prevention & control ; HEK293 Cells ; Humans ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Quinazolines/*pharmacology/toxicity ; Quorum Sensing/*drug effects ; Vibrio cholerae/*drug effects/growth & development ; }, abstract = {Cholera caused by the Gram-negative bacterium Vibrio cholerae still remains a major health burden in developing countries due to its high transmissibility and multidrug resistance. Alternative strategies are in quest to curtail the disease focusing on antivirulent approaches, such as biofilm inhibition, which make bacteria more susceptible to antibiotic therapies. The biofilm state is important for V. cholerae pathogenesis and its persistence in the environment. In the present study, tryptanthrin, a phytochemical, has been identified as possessing strong anti-biofilm activity at sub MIC (2 µg ml[-1]) against V. cholerae. LuxO was identified as the putative target of tryptanthrin by molecular docking and real time analysis. The phytochemical was identified as safe and possessed synergistic action with ciprofloxacin, a commonly used quinolone antibiotic to treat cholera. Collectively, the study establishes the first report on the anti-biofilm property of tryptanthrin by targeting LuxO, which could serve as a potential antivirulent therapy to combat V. cholerae infections.}, } @article {pmid31824466, year = {2019}, author = {Lee, BH and Cole, S and Badel-Berchoux, S and Guillier, L and Felix, B and Krezdorn, N and Hébraud, M and Bernardi, T and Sultan, I and Piveteau, P}, title = {Biofilm Formation of Listeria monocytogenes Strains Under Food Processing Environments and Pan-Genome-Wide Association Study.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2698}, pmid = {31824466}, issn = {1664-302X}, abstract = {Concerns about food contamination by Listeria monocytogenes are on the rise with increasing consumption of ready-to-eat foods. Biofilm production of L. monocytogenes is presumed to be one of the ways that confer its increased resistance and persistence in the food chain. In this study, a collection of isolates from foods and food processing environments (FPEs) representing persistent, prevalent, and rarely detected genotypes was evaluated for biofilm forming capacities including adhesion and sessile biomass production under diverse environmental conditions. The quantity of sessile biomass varied according to growth conditions, lineage, serotype as well as genotype but association of clonal complex (CC) 26 genotype with biofilm production was evidenced under cold temperature. In general, relative biofilm productivity of each strain varied inconsistently across growth conditions. Under our experimental conditions, there were no clear associations between biofilm formation efficiency and persistent or prevalent genotypes. Distinct extrinsic factors affected specific steps of biofilm formation. Sudden nutrient deprivation enhanced cellular adhesion while a prolonged nutrient deficiency impeded biofilm maturation. Salt addition increased biofilm production, moreover, nutrient limitation supplemented by salt significantly stimulated biofilm formation. Pan-genome-wide association study (Pan-GWAS) assessed genetic composition with regard to biofilm phenotypes for the first time. The number of reported genes differed depending on the growth conditions and the number of common genes was low. However, a broad overview of the ontology contents revealed similar patterns regardless of the conditions. Functional analysis showed that functions related to transformation/competence and surface proteins including Internalins were highly enriched.}, } @article {pmid31821931, year = {2020}, author = {Sun, H and Mei, R and Zhang, XX and Ren, H and Liu, WT and Ye, L}, title = {Bacterial enrichment in highly-selective acetate-fed bioreactors and its application in rapid biofilm formation.}, journal = {Water research}, volume = {170}, number = {}, pages = {115359}, doi = {10.1016/j.watres.2019.115359}, pmid = {31821931}, issn = {1879-2448}, mesh = {Acetates ; Bacteria ; Biofilms ; *Bioreactors ; RNA, Ribosomal, 16S ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {In this study, we systematically investigated the bacterial community dynamics in highly-selective (strong hydraulic selection pressure and high organic loading rate) bioreactors with acetate as the sole carbon source. 16S rRNA gene high-throughput sequencing and metagenomic sequencing results showed that phenolics-degrading bacteria (PDB), which were mainly Acinetobacter species, in the newly-formed aerobic granules could account for >70% of the total bacteria. Near full-length 16S rRNA gene sequences obtained by cloning suggest that the PDB are potentially novel species because they are distantly related to known Acinetobacter species. However, these PDB only temporarily appeared in the early stage of the granule formation and their abundance quickly decreased along the reactor operation. To retain these PDB, we demonstrated that the newly-formed aerobic granules could accelerate biofilm formation in moving bed biofilm reactors (MBBRs), and the biofilm carriers showed gradually-increased phenol degradation performance in the MBBRs. While, the bacterial community in biofilm significantly changed during the operation process of the MBBRs and the community structure became more complicated than that in the aerobic granules. Collectively, this study provides new insights into the microbial ecology of sludge granulation and biofilm formation process in the wastewater treatment systems for remediating phenolic matters.}, } @article {pmid31820066, year = {2020}, author = {Khan, F and Lee, JW and Pham, DTN and Lee, JH and Kim, HW and Kim, YK and Kim, YM}, title = {Streptomycin mediated biofilm inhibition and suppression of virulence properties in Pseudomonas aeruginosa PAO1.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {2}, pages = {799-816}, doi = {10.1007/s00253-019-10190-w}, pmid = {31820066}, issn = {1432-0614}, support = {20150220//Ministry of Oceans and Fisheries/ ; R2019053//National Institute of Fisheries Science, Republic of Korea/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Catheters/microbiology ; Culture Media/chemistry ; Gene Expression Profiling ; Hydrogen-Ion Concentration ; Pseudomonas aeruginosa/*drug effects/*growth & development ; Streptomycin/*pharmacology ; Temperature ; Tetracycline/pharmacology ; Tobramycin/pharmacology ; Virulence/*drug effects ; Virulence Factors/biosynthesis ; }, abstract = {Pseudomonas aeruginosa is known as an opportunistic pathogen whose one of the antibiotic resistance mechanisms includes biofilm formation and virulence factor production. The present study showed that the sub-minimum inhibitory concentration (sub-MIC) of streptomycin inhibited the formation of biofilm and eradicated the established mature biofilm. Streptomycin at sub-MIC was also capable of inhibiting biofilm formation on the urinary catheters. In addition, the sub-MIC of streptomycin attenuated the bacterial virulence properties as confirmed by both phenotypic and gene expression studies. The optimal conditions for streptomycin to perform anti-biofilm and anti-virulence activities were proposed as alkaline TSB media (pH 7.9) at 35 °C. However, sub-MIC of streptomycin also exhibited a comparative anti-biofilm efficacy in LB media at similar pH level and temperature. Furthermore, this condition also improved the biofilm inhibition and eradication properties of streptomycin, tobramycin and tetracycline towards the biofilm formed by a clinical isolate of P. aeruginosa. Findings from the present study provide an important insight for further studies on the mechanisms of biofilm inhibition and dispersion of pre-existing biofilm by streptomycin as well as tobramycin and tetracycline under a specific culture environment.}, } @article {pmid31819543, year = {2019}, author = {De Souza, GM and Neto, ERDS and da Silva, AM and Iacia, MVMS and Rodrigues, MVP and Cataneli Pereira, V and Winkelstroter, LK}, title = {Comparative Study Of Genetic Diversity, Virulence Genotype, Biofilm Formation And Antimicrobial Resistance Of Uropathogenic Escherichia coli (UPEC) Isolated From Nosocomial And Community Acquired Urinary Tract Infections.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {3595-3606}, pmid = {31819543}, issn = {1178-6973}, abstract = {INTRODUCTION: Escherichia coli is a Gram-negative opportunistic human pathogen, which has aroused considerable medical interest for being involved in cases of urinary tract infection.

AIM: Characterize the E. coli isolated both in the hospital and in the community.

METHODOLOGY: A total of 200 E. coli isolated in urine samples from hospital and community were evaluated in biofilm formation assay and hydrophobicity MATS method. Antimicrobial susceptibility was performed through agar-diffusion technique. Virulence and ESBL production genes were observed through the polymerase chain reaction amplification of papC, fimH, fliC, kpsMTII, blaTEM, blaCTX-M, blaSHV , and blaOXA. The phylogenetic classification was based on the pattern chuA and yjaA and the region TspE4.C2 by PCR Multiplex.

RESULTS: A higher frequency of non-adherent or poorly adherent isolates was observed in the community group. Approximately 85% of the community isolates were distributed in the highest hydrophilicity group (p<0.05). The level of resistant microorganisms was present at the same level in both source (p>0.05). About 14% of the hospital isolates were positive in the ESBL phenotypic detection test (p>0.05). Among the samples, 95% presented ESBL-encoding genes. The predominant phylogenetic group was B2 (78%). Community isolates showed a higher prevalence of virulence genes fimH, papC, and kpsMTII when compared to hospital samples.

CONCLUSION: These data confirm the worldwide trend that isolates in the community present sometimes higher levels of virulence and antimicrobial resistance.}, } @article {pmid31817559, year = {2019}, author = {Krummenauer, ME and Lopes, W and Garcia, AWA and Schrank, A and Gnoatto, SCB and Kawano, DF and Vainstein, MH}, title = {A Highly Active Triterpene Derivative Capable |of Biofilm Damage to Control Cryptococcus spp.}, journal = {Biomolecules}, volume = {9}, number = {12}, pages = {}, pmid = {31817559}, issn = {2218-273X}, mesh = {Biofilms/*drug effects ; Cell Line ; Cryptococcosis/microbiology/*prevention & control ; Cryptococcus neoformans/drug effects/*physiology ; Drug Resistance, Fungal/drug effects ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Pentacyclic Triterpenes/chemistry/*pharmacology ; Triterpenes/chemistry ; Betulinic Acid ; }, abstract = {Cryptococcus neoformans is an encapsulated yeast responsible for more than 180,000 deaths per year. The standard therapeutic approach against cryptococcosis is a combination of amphotericin B with flucytosine. In countries where cryptococcosis is most prevalent, 5-fluorocytosine is rarely available, and amphotericin B requires intravenous administration. C. neoformans biofilm formation is related to increased drug resistance, which is an important outcome for hospitalized patients. Here, we describe new molecules with anti-cryptococcal activity. A collection of 66 semisynthetic derivatives of ursolic acid and betulinic acid was tested against mature biofilms of C. neoformans at 25 µM. Out of these, eight derivatives including terpenes, benzazoles, flavonoids, and quinolines were able to cause damage and eradicate mature biofilms. Four terpene compounds demonstrated significative growth inhibition of C. neoformans. Our study identified a pentacyclic triterpenoid derived from betulinic acid (LAFIS13) as a potential drug for anti-cryptococcal treatment. This compound appears to be highly active with low toxicity at minimal inhibitory concentration and capable of biofilm eradication.}, } @article {pmid31817522, year = {2019}, author = {Rodríguez-López, P and Barrenengoa, AE and Pascual-Sáez, S and Cabo, ML}, title = {Efficacy of Synthetic Furanones on Listeria monocytogenes Biofilm Formation.}, journal = {Foods (Basel, Switzerland)}, volume = {8}, number = {12}, pages = {}, pmid = {31817522}, issn = {2304-8158}, support = {AGL2016-78549//Ministerio de Ciencia, Innovación y Universidades/ ; }, abstract = {Furanones are analogues of acylated homoserine lactones with proven antifouling activity in both Gram-positive and Gram-negative bacteria though the interference of various quorum sensing pathways. In an attempt to find new strategies to prevent and control Listeria monocytogenes biofilm formation on stainless steel (SS) surfaces, different concentrations of six synthetic furanones were applied on biofilms formed by strains isolated from food, environmental, and clinical sources grown onto AISI 316 SS coupons. Among the furanones tested, (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone and 3,4-Dichloro-2(5H)-furanone significantly (p < 0.05) reduced the adhesion capacity (>1 log CFU cm[-2]) in 24 h treated biofilms. Moreover, individually conducted experiments demonstrated that (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone was able to not only significantly (p < 0.05) prevent L. monocytogenes adhesion but also to reduce the growth rate of planktonic cells up to 48 h in a dose-dependent manner. LIVE/DEAD staining followed by epifluorescence microscopy visualisation confirmed these results show an alteration of the structure of the biofilm in furanone-treated samples. Additionally, it was demonstrated that 20 µmol L[-1] of 3,4-Dichloro-2(5H)-furanone dosed at 0, 24 and 96 h was able to maintain a lower level of adhered cells (>1 log CFU cm[-2]; p < 0.05). Since furanones do not pose a selective pressure on bacteria, these results represent an appealing novel strategy for the prevention of L. monocytogenes biofilm grown onto SS.}, } @article {pmid31817370, year = {2019}, author = {Cattò, C and De Vincenti, L and Cappitelli, F and D'Attoma, G and Saponari, M and Villa, F and Forlani, F}, title = {Non-Lethal Effects of N-Acetylcysteine on Xylella fastidiosa Strain De Donno Biofilm Formation and Detachment.}, journal = {Microorganisms}, volume = {7}, number = {12}, pages = {}, pmid = {31817370}, issn = {2076-2607}, support = {2017-0977//Fondazione Cariplo/ ; DD n. 495 del 14/10/2015 and n. 279 del 9/8/2016, Progetto di ricerca Linea B - STIPXYT//Regione Puglia/ ; }, abstract = {This study investigated in-vitro the non-lethal effects of N-acetylcysteine (NAC) on Xylella fastidiosa subspecies pauca strain De Donno (Xf-DD) biofilm. This strain was isolated from the olive trees affected by the olive quick decline syndrome in southern Italy. Xf-DD was first exposed to non-lethal concentrations of NAC from 0.05 to 1000 µM. Cell surface adhesion was dramatically reduced at 500 µM NAC (-47%), hence, this concentration was selected for investigating the effects of pre-, post- and co-treatments on biofilm physiology and structural development, oxidative homeostasis, and biofilm detachment. Even though 500 µM NAC reduced bacterial attachment to surfaces, compared to the control samples, it promoted Xf-DD biofilm formation by increasing: (i) biofilm biomass by up to 78% in the co-treatment, (ii) matrix polysaccharides production by up to 72% in the pre-treatment, and (iii) reactive oxygen species levels by 3.5-fold in the co-treatment. Xf-DD biofilm detachment without and with NAC was also investigated. The NAC treatment did not increase biofilm detachment, compared to the control samples. All these findings suggested that, at 500 µM, NAC diversified the phenotypes in Xf-DD biofilm, promoting biofilm formation (hyper-biofilm-forming phenotype) and discouraging biofilm detachment (hyper-attachment phenotype), while increasing oxidative stress level in the biofilm.}, } @article {pmid31817122, year = {2019}, author = {Płaczkiewicz, J and Adamczyk-Popławska, M and Lasek, R and Bącal, P and Kwiatek, A}, title = {Inactivation of Genes Encoding MutL and MutS Proteins Influences Adhesion and Biofilm Formation by Neisseria gonorrhoeae.}, journal = {Microorganisms}, volume = {7}, number = {12}, pages = {}, pmid = {31817122}, issn = {2076-2607}, support = {UMO-2014/15/B/NZ6/02514//Narodowe Centrum Nauki/ ; NN301 165135//Ministry of Science and Higher Education in Poland/ ; }, abstract = {Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem. This bacterium possesses MutL and MutS DNA repair proteins encoded by mutL and mutS genes, whose inactivation causes a mutator phenotype. We have demonstrated the differential gene expression in N. gonorrhoeae mutL and mutS mutants using DNA microarrays. A subset of differentially expressed genes encodes proteins that can influence adhesion and biofilm formation. Compared to the wild-type strain, N. gonorrhoeae mutL and mutS mutants formed denser biofilms with increased biofilm-associated biomass on the abiotic surface. The N. gonorrhoeae mutS::km, but not the mutL mutant, was also more adherent and invasive to human epithelial cells. Further, during infection of epithelial cells with N. gonorrhoeae mutS::km, the expression of some bacterial genes encoding proteins that can influence gonococcal adhesion was changed compared with their expression in cells infected with the wild-type gonococcus, as well as of human genes' encoding receptors utilized by N. gonorrhoeae (CD46, CEACAM 1, HSPG 2). Thus, deficiency in the mutS gene resulting in increased mutation frequency in singular organisms can be beneficial in populations because these mutants can be a source of features linked to microbial fitness.}, } @article {pmid31817114, year = {2019}, author = {Rampacci, E and Marenzoni, ML and Giovagnoli, S and Passamonti, F and Coletti, M and Pietrella, D}, title = {Phenotypic Characterization of Rhodococcus equi Biofilm Grown In Vitro and Inhibiting and Dissolving Activity of Azithromycin/Rifampicin Treatment.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31817114}, issn = {2076-0817}, abstract = {Microbial biofilm has been implicated in a wide range of chronic infections. In spite of the fact that Rhodococcus equi is a recognized cause of chronic disease in animals and humans, few studies have focused on the sessile phenotype of R. equi. The aim of this research was to phenotypically characterize the biofilm development of R. equi and its answerability for hypo-responsiveness to macrolides and rifampicin. Biofilm formation is initiated by bacterial adhesion to the surface. In this work, the ability of R. equi to adhere to the surface of human lung epithelial cells was detected by a fluorometric adhesion test performed on 40 clinical isolates. Subsequently, the capability of R. equi to produce biofilm was investigated by colorimetric, fluorescence and scanning electron microscopy analysis, revealing a general slow growth of rhodococcal biofilm and different sessile phenotypes among field isolates, some also including filamented bacteria. Azithromycin treatment produced a higher long-term inhibition and dissolution of R. equi biofilms than rifampicin, while the two antibiotics combined boosted the anti-biofilm effect in a statistically significant manner, although this was not equally effective for all R. equi isolates. Increasing the MIC concentrations of drugs tenfold alone and in combination did not completely eradicate pre-formed R. equi biofilms, while a rifampicin-resistant isolate produced an exceptionally abundant extracellular matrix. These results have strengthened the hypothesis that biofilm production may occur as an antibiotic tolerance system in R. equi, potentially determining persistence and, eventually, chronic infection.}, } @article {pmid31816593, year = {2020}, author = {Chatterjee, S and Ghosh, R and Mandal, NC}, title = {Inhibition of biofilm- and hyphal- development, two virulent features of Candida albicans by secondary metabolites of an endophytic fungus Alternaria tenuissima having broad spectrum antifungal potential.}, journal = {Microbiological research}, volume = {232}, number = {}, pages = {126386}, doi = {10.1016/j.micres.2019.126386}, pmid = {31816593}, issn = {1618-0623}, mesh = {Alternaria/isolation & purification/*metabolism ; Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects ; Candidiasis ; Endophytes/isolation & purification/*metabolism ; Fluconazole/pharmacology ; Hyphae/*drug effects/growth & development ; India ; Microbial Sensitivity Tests ; Ocimum sanctum/microbiology ; Secondary Metabolism ; }, abstract = {Fungal resistance against frequently used antifungal medicines used for invasive candidiasis and other fungal infections is directing scientist for searching and developing novel antifungal drugs. An endophytic fungal strain Alternaria tenuissima OE7 has been isolated from leaves of Ocimum tenuiflorum L. which showed antifungal activity against numbers of human pathogenic fungi including Trichophyton rubrum, Microsporum gypseum, Aspergillus parasiticus, A. flavus, A. fumigates, Candida albicans and C. tropicalis. Thermostable, non-proteinacious antifungal metabolites produced zones of inhibition against all pathogenic fungi tested. The ethyl acetate extract of the cell free supernatant was found inhibitory to the radial growth and conidial germination of T. rubrum and M. gypseum. It also showed cidal mode of action against C. albicans at a concentration of 1.0 mg/ml. Most interestingly, inhibition of biofilm formation and hyphal development of C. albicans were observed upon treatment with EA fraction at comparatively lower concentrations (100-500 μg/ml). Release of intracellular contents from treated cells of Candida and scanning electron microscopic observation suggested cellular disruptions by antifungal metabolites. Checkerboard study revealed synergy between EA fraction of OE7 (150 μg/ml) and fluconazole (30 μg/ml) with ƩFIC of 0.45. Two active fractions viz. band 'C' and band 'G' derived after thin layer chromatographic analysis showed inhibitory activity against C. albicans with MIC values of 80 μg/ml and 130 μg/ml respectively. GCMS analysis suggested presence of numbers of compounds in each active fraction. Overall observations attest the prospective role of the isolate OE7 as a potent candidate for the production of antifungal metabolites against human pathogenic fungi.}, } @article {pmid31816527, year = {2020}, author = {Lebleux, M and Abdo, H and Coelho, C and Basmaciyan, L and Albertin, W and Maupeu, J and Laurent, J and Roullier-Gall, C and Alexandre, H and Guilloux-Benatier, M and Weidmann, S and Rousseaux, S}, title = {New advances on the Brettanomyces bruxellensis biofilm mode of life.}, journal = {International journal of food microbiology}, volume = {318}, number = {}, pages = {108464}, doi = {10.1016/j.ijfoodmicro.2019.108464}, pmid = {31816527}, issn = {1879-3460}, mesh = {Biofilms/*growth & development ; Brettanomyces/cytology/genetics/*physiology ; Food Microbiology ; Wine/analysis/*microbiology ; }, abstract = {The wine spoilage yeast Brettanomyces bruxellensis can be found at several steps in the winemaking process due to its resistance to multiple stress conditions. The ability to form biofilm is a potential resistance strategy, although it has been given little attention so far for this yeast. In this work, the capacity to form biofilm and its structure were explored in YPD medium and in wine. Using microsatellite analysis, 65 isolates were discriminated into 5 different genetic groups from which 12 strains were selected. All 12 strains were able to form biofilm in YPD medium on a polystyrene surface. The presence of microcolonies, filamentous cells and extracellular polymeric substances, constituting the structure of the biofilm despite a small thickness, were highlighted using confocal and electronic microscopy. Moreover, different cell morphologies according to genetic groups were highlighted. The capacity to form biofilm in wine was also revealed for two selected strains. The impact of wine on biofilms was demonstrated with firstly considerable biofilm cell release and secondly growth of these released biofilm cells, both in a strain dependent manner. Finally, B. bruxellensis has been newly described as a producer of chlamydospore-like structures in wine, for both planktonic and biofilm lifestyles.}, } @article {pmid31815139, year = {2019}, author = {Bao, L and Guo, J and Feng, L and Zhou, X and Lu, Q}, title = {Efficacy of Artesunate against Pseudomonas aeruginosa Biofilm Mediated by Iron.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {4810217}, pmid = {31815139}, issn = {2314-6141}, mesh = {Anti-Infective Agents/pharmacology ; Artesunate/*pharmacology ; Biofilms/*drug effects/*growth & development ; Culture Media/chemistry ; Iron/*metabolism ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/*growth & development ; }, abstract = {Pseudomonas aeruginosa is capable of causing a variety of chronic infections due to the formation of biofilms. Iron is essential for growth of Pseudomonas aeruginosa, and therapies that interfere with iron may help treat P. aeruginosa infections. Herein, we investigated whether artesunate, which is a type of iron-dependent drug, could influence Pseudomonas aeruginosa biofilm formation and structure, including the underlying mechanisms. Artesunate could enhance twitching motility significantly and decrease the proportion of surviving cells in Pseudomonas aeruginosa biofilms in a dose-dependent manner. Artesunate treatment also reduced biofilm thickness, diffusion in the biomass, and the content of Fe(II). However, changes in biofilm structure and ion concentration were very similar following treatment with 512 μg/ml and 1024 μg/ml artesunate. Interestingly, both biofilm structure and surviving cell fraction were recovered after iron supplementation. These results suggest that artesunate interferes with Pseudomonas aeruginosa biofilms by decreasing bacterial viability and enhancing twitching motility in an iron-independent manner.}, } @article {pmid31814741, year = {2019}, author = {Eze, EC and El Zowalaty, ME}, title = {Combined Effects Of Low Incubation Temperature, Minimal Growth Medium, And Low Hydrodynamics Optimize Acinetobacter baumannii Biofilm Formation.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {3523-3536}, pmid = {31814741}, issn = {1178-6973}, abstract = {BACKGROUND: Biofilm formation is an important virulence factor expressed by Acinetobacter baumannii. It shields and protects microbial cells from host immune responses, antibiotics, and other anti-infectives. Its effects on Acinetobacter baumannii infection treatments notwithstanding, important environmental factors that influence its formation have not been fully investigated.

METHODS: Biofilm formation was assessed using the qualitative modified Congo red assay and quantitative microtiter plate methods. The combined effect of temperature, medium and shear force was determined by measuring adherence (OD570 nm) in microtiter plate after incubation at 26°C, 30°C, and 37°C when biofilm-grown cells were cultured in the presence of minimal nutrient medium (EAOB) and nutrient-rich medium (TSB) without or with agitation at 50 rpm. Antibiotics susceptibility of meropenem, imipenem, and ciprofloxacin were tested with Kirby-Bauer disc method. P<0.05 was considered statistically significant in all the tests.

RESULTS: A noticeable variation in adherence was observed among the isolates cultured with both media. Biofilm forming capacity of the isolates range from 0.09-0.33. The majority of the isolates had their relative biofilm-forming capacity significantly (p<0.05) higher than the positive control, Acinetobacter baumannii ATCC 19606. The biofilm biomass during growth in nutrient-rich medium (TSB) without shaking was significantly different (p<0.05; Tukey's test) among the three temperatures tested compared with when it was cultured in EAOB without shaking. A positive correlation was observed between biofilm formation and resistance to imipenem (r=0.2889; p=0.05). There was a statistically significant difference among the median of the three source groups (p<0.05) compared with the median between the source groups.

CONCLUSION: This observation extended further the view that A. baumannii biofilm formation is enhanced when nutrient-poor medium is used at room temperature (26°C) with or without agitation compared to growth at 37°C.}, } @article {pmid31814249, year = {2020}, author = {Fiallos, NM and Cecchin, D and de Lima, CO and Hirata, R and Silva, EJNL and Sassone, LM}, title = {Antimicrobial effectiveness of grape seed extract against Enterococcus faecalis biofilm: A Confocal Laser Scanning Microscopy analysis.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {46}, number = {2}, pages = {191-196}, doi = {10.1111/aej.12390}, pmid = {31814249}, issn = {1747-4477}, support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; E-26/202.839/2015//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Biofilms ; Chlorhexidine ; Dentin ; *Enterococcus faecalis ; *Grape Seed Extract ; Microscopy, Confocal ; Root Canal Irrigants ; Sodium Hypochlorite ; }, abstract = {This study evaluated the antimicrobial effectiveness of 6.5% Vitis vinifera grape seed extract (GSE) against Enterococcus faecalis biofilm using confocal laser scanning microscopy (CLSM). Saline solution (SS), 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) were used for comparison. Dentin discs were inoculated with E. faecalis strain establishing a 3-week-old biofilm. Discs (n = 10) were exposed to 5.25% NaOCl, 2% CHX, 6.5% GSE and SS (negative control) for 10 min. Discs were stained with the fluorescent LIVE/DEAD-BacLight™ dye and analysed using CLSM. The proportion of dead cells in biofilm was analysed using one-way anova and Tukey tests (P < 0.05). A higher proportion of dead cells was found in GSE group compared with CHX and SS (P < 0.05). NaOCl group was associated with the highest proportion of dead cells (P < 0.05). GSE presented antimicrobial activity against E. faecalis; however, NaOCl was the most effective irrigant solution. GSE was more effective than CHX and SS.}, } @article {pmid31813834, year = {2020}, author = {Su, S and Yin, P and Li, J and Chen, G and Wang, Y and Qu, D and Li, Z and Xue, X and Luo, X and Li, M}, title = {In vitro and in vivo anti-biofilm activity of pyran derivative against Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {Journal of infection and public health}, volume = {13}, number = {5}, pages = {791-799}, doi = {10.1016/j.jiph.2019.10.010}, pmid = {31813834}, issn = {1876-035X}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/microbiology ; Disease Models, Animal ; Female ; Male ; Mice ; Microbial Sensitivity Tests ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects ; Pyrans/chemistry/*pharmacology ; Quorum Sensing ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects ; Urinary Tract Infections/microbiology ; }, abstract = {BACKGROUND: The development of bacterial biofilm can cause severe chronic infections and antibiotic resistance. Therefore, it poses a significant threat to public health. Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) are two major pathogens that can cause biofilm-associated infections, which leads to the urgent necessity of developing new agents with biofilm-forming inhibitory ability.

METHODS: A series of pyran derivatives were synthesized and characterized, and their in vitro anti-biofilm activity against S. aureus and P. aeruginosa were measured by minimal biofilm inhibitory concentration assay and FITC dye staining. The in vivo antibiofilm therapeutical effects were evaluated in S. aureus induced tissue cage infection mice model and P. aeruginosa induced urinary tract catheter infection rat model.

RESULTS: Several pyran derivatives showed the in vitro anti-biofilm activity against S. aureus and P. aeruginosa, and the activity of these compounds was not mediated through the accessory gene regulator (agr) quorum sensing system of S. aureus. One of these pyran derivatives, namely 2-amino-4-(2,6-dichlorophenyl)-3-cyano-5-oxo-4H,5H-pyrano[3,2c]chromene, exhibited significant inhibitory biofilm-formation activity in S. aureus tissue cage infection mice model and in the P. aeruginosa-infected urinary tract catheters of experimental rats.

CONCLUSIONS: The data indicated that this pyran derivative is a possible lead compound that can be used for the development of novel anti-biofilm agents against S. aureus and P. aeruginosa infection.}, } @article {pmid31813049, year = {2020}, author = {Liu, Y and Feng, H and Fu, R and Zhang, N and Du, W and Shen, Q and Zhang, R}, title = {Induced root-secreted D-galactose functions as a chemoattractant and enhances the biofilm formation of Bacillus velezensis SQR9 in an McpA-dependent manner.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {2}, pages = {785-797}, doi = {10.1007/s00253-019-10265-8}, pmid = {31813049}, issn = {1432-0614}, support = {31672232//National Natural Science Foundation of China/ ; 31600088//National Natural Science Foundation of China/ ; 31572214//National Natural Science Foundation of China/ ; 2018YFD0500201//the National Key R & D Program of China/ ; }, mesh = {Bacillus/*drug effects/genetics/*growth & development ; Biofilms/growth & development ; Chemotactic Factors/*metabolism ; Chemotaxis ; Cucumis sativus/*metabolism/microbiology ; Galactose/*metabolism ; Gene Deletion ; Methyl-Accepting Chemotaxis Proteins/deficiency/metabolism ; Plant Roots/*metabolism/microbiology ; }, abstract = {Chemotaxis towards root exudates and subsequent biofilm formation are very important for root colonization and for providing the beneficial functions of plant growth-promoting rhizobacteria (PGPRs). In this study, in comparison with other root-secreted compounds, D-galactose in the root exudates of cucumber was found to be a strong chemoattractant at the concentration of 1 μM for Bacillus velezensis SQR9. Chemotaxis assays with methyl-accepting chemotaxis proteins (MCPs) deletion strains demonstrated that McpA was solely responsible for chemotaxis towards D-galactose. Interestingly, D-galactose significantly enhanced the biofilm formation of SQR9 in an McpA-dependent manner. Further experiment showed that D-galactose also enhanced root colonization by SQR9. In addition, the secretion of D-galactose by cucumber roots could be induced by inoculation with SQR9, indicating that D-galactose may be an important signal in the interaction between plant and SQR9. These findings suggested that the root-secreted D-galactose was a signal, the secretion of which was induced by the beneficial bacteria, and which in turn induced colonization of the bacteria.}, } @article {pmid31812976, year = {2019}, author = {Płusa, T}, title = {[The importance of biofilm in the context of increasing bacterial resistance to antibiotics].}, journal = {Polski merkuriusz lekarski : organ Polskiego Towarzystwa Lekarskiego}, volume = {47}, number = {281}, pages = {197-202}, pmid = {31812976}, issn = {1426-9686}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Metal Nanoparticles ; Pseudomonas aeruginosa ; Silver ; }, abstract = {Biofilm is a form of bacterial life in extreme environmental conditions. The known structure and functions of biofilm indicate that it is one of the most widespread and most successful life forms on earth. The quorum sensing (QS) system plays a key role in biofilm because it is a mechanism by which bacteria regulate the gene expression profile according to the size of the microbial population, causing the formation of different forms of biofilm. The QS includes the auto-inducer-1 (AI- 1) system, which uses N-acyl-homoserine lactones as a signaling factor in the formation of biofilm by Acinetobacter baumannii and Pseudomonas aeruginosa, and the auto-inducer-2 (AI-2) system identified as furanosyl borate diester present in Gram-positive and Gram-negative bacteria. Antimicrobial proteins (AMPs) have a natural antibacterial effect, which are produced by eukaryocytes and prokaryocytes, and have the ability to form pores in the bacterial cell membrane or interfere with its function. On the other hand, biofilm degrading enzymes - DNase I, alpha-amylase and dispersin B - reduce the weight of exopolysaccharides (EPS) and the number of cells in the biofilm. Natural compounds that inhibit the formation of bacterial biofilm have been distinguished, so-called QS inhibitors (QSI) and which "quench" active process (QSQ). In turn, genetic diversification of microorganisms in biofilm is largely responsible for shaping antibiotic resistance. The combined use of antibiotics with nanoparticles seems to be the most promising therapeutic option for bacterial biofilm. Silver nanoparticles with citrate in combination with aztreonam have been shown to have significant biofilm-destroying efficacy for Pseudomonas aeruginosa, and selenium nanoparticles used together with ampicillin, oxacillin and penicillin in 94% inhibited and interrupted the MRSA (methicillin-resistent) biofilm. Research on biofilm control is very advanced and will soon be subject to clinical evaluation.}, } @article {pmid31812797, year = {2020}, author = {Borowski, RGV and Barros, MP and da Silva, DB and Lopes, NP and Zimmer, KR and Staats, CC and de Oliveira, CB and Giudice, E and Gillet, R and Macedo, AJ and Gnoatto, SCB and Zimmer, AR}, title = {Red pepper peptide coatings control Staphylococcus epidermidis adhesion and biofilm formation.}, journal = {International journal of pharmaceutics}, volume = {574}, number = {}, pages = {118872}, doi = {10.1016/j.ijpharm.2019.118872}, pmid = {31812797}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Capsicum/*chemistry ; Cell Line, Tumor ; Coated Materials, Biocompatible/chemistry ; HCT116 Cells ; Humans ; MCF-7 Cells ; PC-3 Cells ; Peptides/*pharmacology ; Staphylococcal Infections/*drug therapy ; Staphylococcus epidermidis/*drug effects ; Tandem Mass Spectrometry/methods ; }, abstract = {Medical devices (indwelling) have greatly improved healthcare. Nevertheless, infections related to the use of these apparatuses continue to be a major clinical concern. Biofilms form on surfaces after bacterial adhesion, and they function as bacterial reservoirs and as resistance and tolerance factors against antibiotics and the host immune response. Technological strategies to control biofilms and bacterial adhesion, such as the use of surface coatings, are being explored more frequently, and natural peptides may promote their development. In this study, we purified and identified antibiofilm peptides from Capsicum baccatum (red pepper) using chromatography-tandem mass spectrometry, MALDI-MS, MS/MS and bioinformatics. These peptides strongly controlled biofilm formation by Staphylococcus epidermidis, the most prevalent pathogen in device-related infections, without any antibiotic activity. Furthermore, natural peptide-coated surfaces dislayed effective antiadhesive proprieties and showed no cytotoxic effects against different representative human cell lines. Finally, we determined the lead peptide predicted by Mascot and identified CSP37, which may be useful as a prime structure for the design of new antibiofilm agents. Together, these results shed light on natural Capsicum peptides as a possible antiadhesive coat to prevent medical device colonization.}, } @article {pmid31812752, year = {2020}, author = {Garcia, LGS and de Melo Guedes, GM and Fonseca, XMQC and Pereira-Neto, WA and Castelo-Branco, DSCM and Sidrim, JJC and de Aguiar Cordeiro, R and Rocha, MFG and Vieira, RS and Brilhante, RSN}, title = {Antifungal activity of different molecular weight chitosans against planktonic cells and biofilm of Sporothrix brasiliensis.}, journal = {International journal of biological macromolecules}, volume = {143}, number = {}, pages = {341-348}, doi = {10.1016/j.ijbiomac.2019.12.031}, pmid = {31812752}, issn = {1879-0003}, mesh = {Biofilms/*drug effects ; Chitosan/chemistry/*pharmacology ; Humans ; Molecular Weight ; Plankton/drug effects ; Sporothrix/*drug effects/growth & development ; Sporotrichosis/drug therapy/pathology ; }, abstract = {Sporotrichosis, caused by Sporothrix schenckii complex species, is the most prevalent subcutaneous mycosis in many areas of Latin America. Chitosan has been used as an antifungal agent; however the effects of the molecular weight (MW) of chitosan (i.e. high (HMW), medium (MMW) and low (LMW) molecular weight chitosan) on S. brasiliensis has not been well described, particularly on biofilms. Effects on the planktonic form activity of S. brasiliensis were quantified by broth microdilution, while anti-biofilm activity was quantified by measuring metabolic activity via XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide and biomass formation (crystal violet). The molecular weight of chitosan modulated its effect on the planktonic form of S. brasiliensis, presenting lower MIC values for LMW chitosan. With regards both the adhesive and mature phases of biofilm, the LMW chitosan reduced biomass and metabolic activity most effectively. This study confirms the effects of the molecular weight and deacetylation degree of chitosan on its antifungal properties for potentially pathogenic fungi.}, } @article {pmid31812393, year = {2020}, author = {Wang, J and Liu, Q and Wu, B and Hu, H and Dong, D and Yin, J and Ren, H}, title = {Effect of salinity on mature wastewater treatment biofilm microbial community assembly and metabolite characteristics.}, journal = {The Science of the total environment}, volume = {711}, number = {}, pages = {134437}, doi = {10.1016/j.scitotenv.2019.134437}, pmid = {31812393}, issn = {1879-1026}, mesh = {Bacteria ; Biofilms ; *Microbiota ; Salinity ; *Wastewater ; }, abstract = {The response mechanism of wastewater treatment biofilms to salt stress has not yet been fully established. The aim of this study was to reveal the comprehensive biological effects of salinity on biofilm microbial community and metabonomic characteristics. The study assessed performance at a range of sodium chloride (NaCl) concentrations of 0.6, 14 and 20 g/L. Biofilm coverage rate decreased significantly with increasing NaCl concentrations. High NaCl concentrations resulted in more compact and smoother biofilm morphologies. NaCl concentrations affected bacterial community variation at the class and genus level, with Gammaproteobacteria being the most dominant Proteobacteria, exhibiting NaCl tolerance at concentrations ranging from 0 to 20 g/L. Also, NaCl sensitive or tolerant species were identified, such as Pseudomonas and Planococcus, respectively. Dominant metabolites in wastewater treatment biofilms belonging to nucleotide, lipid, vitamin, amino acid and carbohydrate metabolism pathways decreased with increasing NaCl concentrations. High concentrations of NaCl regulated cell motility, transcription and membrane transport functions. In particular, the activity of ABC transporters were up-regulated at NaCl concentrations of 0.6 g/L and down-regulated at higher salinity concentrations. In addition, transcription machinery were inhibited under the stress of 14 g/L NaCl. These findings further our understanding of the short-term adaption mechanisms of wastewater treatment biofilms to high NaCl concentration environments.}, } @article {pmid31812076, year = {2020}, author = {Rahim, MI and Szafrański, SP and Ingendoh-Tsakmakidis, A and Stiesch, M and Mueller, PP}, title = {Evidence for inoculum size and gas interfaces as critical factors in bacterial biofilm formation on magnesium implants in an animal model.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {186}, number = {}, pages = {110684}, doi = {10.1016/j.colsurfb.2019.110684}, pmid = {31812076}, issn = {1873-4367}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Disease Models, Animal ; Female ; Gases/chemistry ; Magnesium/*pharmacology ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Particle Size ; Pseudomonas aeruginosa/*drug effects ; Surface Properties ; }, abstract = {Infections of medical implants caused by bacterial biofilms are a major clinical problem. Bacterial colonization is predicted to be prevented by alkaline magnesium surfaces. However, in experimental animal studies, magnesium implants prolonged infections. The reason for this peculiarity likely lies within the ‒still largely hypothetical‒ mechanism by which infection arises. Investigating subcutaneous magnesium implants infected with bioluminescent Pseudomonas aeruginosa via in vivo imaging, we found that the rate of implant infections was critically dependent on a surprisingly high quantity of injected bacteria. At high inocula, bacteria were antibiotic-refractory immediately after infection. High cell densities are known to limit nutrient availability, restricting proliferation and trigger quorum sensing which could both contribute to the rapid initial resistance. We propose that gas bubbles such as those formed during magnesium corrosion, can then act as interfaces that support biofilm formation and permit long-term survival. This model could provide an explanation for the apparent ineffectiveness of innovative contact-dependent bactericidal implant surfaces in patients. In addition, the model points toward air bubbles in tissue, either by inclusion during surgery or by spontaneous gas bubble formation later on, could constitute a key risk factor for clinical implant infections.}, } @article {pmid31812042, year = {2020}, author = {Suárez, JI and Aybar, M and Nancucheo, I and Poch, B and Martínez, P and Rittmann, BE and Schwarz, A}, title = {Influence of operating conditions on sulfate reduction from real mining process water by membrane biofilm reactors.}, journal = {Chemosphere}, volume = {244}, number = {}, pages = {125508}, doi = {10.1016/j.chemosphere.2019.125508}, pmid = {31812042}, issn = {1879-1298}, mesh = {Autotrophic Processes ; Bacteria ; Biofilms ; Bioreactors/*microbiology ; Hydrogen/chemistry ; Membranes ; Membranes, Artificial ; *Mining ; Oxidation-Reduction ; Sulfates/chemistry/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; Water Pollutants, Chemical/analysis/*metabolism ; Water Purification/methods ; }, abstract = {Two H2-based membrane biofilm reactor (H2-MBfR) systems, differing in membrane type, were tested for sulfate reduction from a real mining-process water having low alkalinity and high concentrations of dissolved sulfate and calcium. Maximum sulfate reductions were 99%, with an optimum pH range between 8 and 8.5, which minimized any toxic effect of unionized hydrogen sulfide (H2S) on sulfate-reducing bacteria (SRB) and calcite scaling on the fibers and in the biofilm. Although several strategies for control of pH and gas back-diffusion were applied, it was not possible to sustain a high degree of sulfate reduction over the long-term. The most likely cause was precipitation of calcite inside the biofilm and on the surface of fibers, which was shown by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) analysis. Another possible cause was a decline in pH, leading to inhibition by H2S. A H2/CO2 mixture in the gas supply was able to temporarily recover the effectiveness of the reactors and stabilize the pH. Biomolecular analysis showed that the biofilm was comprised of 15-20% SRB, but a great variety of autotrophic and heterotrophic genera, including sulfur-oxidizing bacteria, were present. Results also suggest that the MBfR system can be optimized by improving H2 mass transfer using fibers of higher gas permeability and by feeding a H2/CO2 mixture that is automatically adjusted for pH control.}, } @article {pmid31811888, year = {2020}, author = {Narenji, H and Teymournejad, O and Rezaee, MA and Taghizadeh, S and Mehramuz, B and Aghazadeh, M and Asgharzadeh, M and Madhi, M and Gholizadeh, P and Ganbarov, K and Yousefi, M and Pakravan, A and Dal, T and Ahmadi, R and Samadi Kafil, H}, title = {Antisense peptide nucleic acids againstftsZ andefaA genes inhibit growth and biofilm formation of Enterococcusfaecalis.}, journal = {Microbial pathogenesis}, volume = {139}, number = {}, pages = {103907}, doi = {10.1016/j.micpath.2019.103907}, pmid = {31811888}, issn = {1096-1208}, mesh = {Antigens, Bacterial/*genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Cytoskeletal Proteins/*genetics/metabolism ; Enterococcus faecalis/*genetics/growth & development/physiology ; Gene Expression Regulation, Bacterial ; Peptide Nucleic Acids/*genetics ; }, abstract = {Enterococcus faecalis is one of the important causes of nosocomial infections. Nowadays, increasing prevalence of antibiotic-resistant bacteria and slow progress in recognizing new antimicrobial agents has limited the efficiency of conventional antibiotics, which cause to find novel strategies to overcome bacteria. Therefore, in this study, we aimed to assess the role of efaA gene in the biofilm formation and the role of ftsZ gene in the controlling of bacterial growth by the anti-sense PNAs(Peptide Nucleic Acid).E. faecalis ATCC® 29212™was used for the study of PNAs designed to targeting the start codon section of the ftsZ andefaA genes. PNA attachment to RNA was confirmed by blotting. Electroporation technique was used for the intracellular transfer of anti-ftsZ PNAs. The spot-plating method was used to the assessment of alteration in bacterial growth. Biofilm formation assay and real-time PCR were used for detection of biofilm inhibitory effect of cell penetrating peptide (CPP) conjugated to anti-efaA PNAs.ByftsZ PNAs treatment, no growth was seen from the strain in agar by a spot plating method and the inhibition zone of anti-ftsZ PNAs was not seen. PNAs against the efaA gene decreased by 95% the expression of the efaA gene and biofilm formation. In addition, the(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) MTT assay showed no toxicity on MCF7 cells for both of anti-ftsZand anti-efaA PNAs.This study used new genetic and molecular tools to inhibit pathogenicity and infection by E. faecalis. In this study, we suggested that efaA gene plays a critical role in the biofilm formation and anti-efaA PNAs could decrease the formation of biofilm, as well as, anti-ftsZ PNAs could eliminate bacterial growth.}, } @article {pmid31811560, year = {2020}, author = {Çam, S and Brinkmeyer, R}, title = {The effects of temperature, pH, and iron on biofilm formation by clinical versus environmental strains of Vibrio vulnificus.}, journal = {Folia microbiologica}, volume = {65}, number = {3}, pages = {557-566}, doi = {10.1007/s12223-019-00761-9}, pmid = {31811560}, issn = {1874-9356}, mesh = {Aquatic Organisms ; Biofilms/*growth & development ; *Environmental Microbiology ; Hydrogen-Ion Concentration ; Iron/*pharmacology ; Phenotype ; *Temperature ; Vibrio vulnificus/*drug effects/*physiology ; Virulence Factors ; }, abstract = {Due to the nature of Vibrio vulnificus infections (i.e., gastroenteritis and septicemia), only very few studies of a biofilm-associated form in this pathogen's life cycle have been conducted. We proposed that biofilm production by clinical strains of V. vulnificus would be higher than by environmental strains. Biofilm formation by clinical and environmental reference strains was tested under different temperatures (24, 30, and 37 °C), pH (5.5, 7.5, and 8.5) and iron concentrations (18, 30, 50, 100, and 200 μM). Biofilm production by clinical strains was consistently higher (p < 0.001) at 24 °C than by environmental strains. Higher biofilm production was observed at pH 5.5 by all strains. Growth rates were lowest at pH 5.5 for environmental strains but for clinical strains there were no differences at pH 5.5, 7.5, and 8.5, demonstrating a tolerance to acidic and alkaline conditions. There was a strong, direct correlation between iron concentration in the growth medium and biofilm production by all strains tested. The current study indicates that biofilm formation might be important for the survival of V. vulnificus in vivo as well as in the marine environment. With regard to temperature and pH, higher biofilm production appears to be a trait of clinical strains and could be considered a virulence determinant in V. vulnificus.}, } @article {pmid31811221, year = {2019}, author = {Husain, FM and Ansari, AA and Khan, A and Ahmad, N and Albadri, A and Albalawi, TH}, title = {Mitigation of acyl-homoserine lactone (AHL) based bacterial quorum sensing, virulence functions, and biofilm formation by yttrium oxide core/shell nanospheres: Novel approach to combat drug resistance.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {18476}, pmid = {31811221}, issn = {2045-2322}, mesh = {*Acyl-Butyrolactones ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Chromobacterium/drug effects/growth & development ; Drug Resistance/*drug effects ; Nanospheres ; Pseudomonas aeruginosa/drug effects/growth & development ; Quorum Sensing/*drug effects ; Virulence/drug effects ; *Yttrium ; }, abstract = {The present study evaluated the efficacy of Y2O3:Tb (core) and Y2O3:Tb@SiO2 nanospheres (core/shell NSs) against virulence functions regulated by quorum sensing (QS) and biofilm formation in pathogenic bacteria. Scanning electron microscope (SEM) images were used to study the size, shape, and morphology. The images clearly displayed spherical shaped, mono-dispersed particles with narrow size distribution and an average grain size of 110-130 nm. The chemical composition of the samples was determined by using energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). We determined the impact of core and core/shell NSs on QS using sensor strains of Chromobacterium violaceum CVO26 and Pseudomonas aeruginosa PAO1 in a comparative study. Sub-MICs of core and core/shell NSs substantially suppressed QS-controlled violacein production in C. violaceum. Similar concentration-dependent effect of sub-MICs of synthesized core and core/shell NSs was observed in the QS-regulated virulence functions (elastase, total protease, pyocyanin production, swarming motility, and exopolysaccharide production) in PAO1. A concentration-dependent decrease (14-60%) was recorded in the biofilm forming capability of PAO1, upon treatment with core and core/shell NSs. Moreover, core/shell NSs were more effective in inhibiting biofilm at higher tested concentrations as compared to core-NSs. The synthesized NSs demonstrated significantly impaired attachment of cells to the microtiter plate indicating that NSs target biofilm inhibition at the attachment stage. Based on these results, we predict that core and core/shell NSs may be an alternative to combat the threat of drug-resistant pathogenic bacteria.}, } @article {pmid31809574, year = {2020}, author = {Li, Q and Yin, L and Xue, M and Wang, Z and Song, X and Shao, Y and Liu, H and Tu, J and Qi, K}, title = {The transcriptional regulator PhoP mediates the tolC molecular mechanism on APEC biofilm formation and pathogenicity.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {49}, number = {3}, pages = {211-220}, doi = {10.1080/03079457.2019.1701182}, pmid = {31809574}, issn = {1465-3338}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Chickens ; DNA, Bacterial/genetics ; Drug Resistance, Bacterial ; Electrophoretic Mobility Shift Assay ; Escherichia coli/genetics/*metabolism/pathogenicity/physiology ; Escherichia coli Infections/microbiology/veterinary ; Escherichia coli Proteins/genetics/*metabolism ; Gene Deletion ; Gene Expression Regulation, Bacterial/physiology ; Liver/pathology ; Membrane Transport Proteins/genetics/*metabolism ; Oligonucleotide Array Sequence Analysis ; }, abstract = {As a transcriptional regulator of the classical binary regulatory system, PhoP plays an important role in the life activities of avian pathogenic Escherichia coli (APEC). In previous experiments, we found that the absence of phoP affects APEC biofilm formation and pathogenicity. To further explore the molecular mechanism of phoP regulation of these phenomena, the differentially expressed gene tolC was screened based on phoP-derived transcriptional data, and the specific sequence identity of the PhoP binding sequence was predicted by bioinformatics and verified by electrophoretic mobility shift assay (EMSA). The results showed that PhoP can directly bind to the tolC promoter. On this basis, tolC deletion and complementary strains were constructed. Biofilm formation was quantified by crystal violet staining and rdar morphology change was observed in these strains. Loss of tolC reduced biofilm formation. We also examined pathological changes in organ paraffin sections by challenging chicks with the strains. After loss of tolC, the clinical signs of pericarditis and liver and spleen enlargement in chicks were alleviated, and pathogenicity to the host cells was decreased. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that tolC deletion downregulated secA/secB/secE/secY transcript levels, which are part of the type II secretion system secreting virulence effector element. These results indicate that tolC contributes to the phoP-mediated effect on APEC biofilm formation and pathogenicity.}, } @article {pmid31809192, year = {2020}, author = {Ma, Z and Stanford, K and Bie, XM and Niu, YD and McAllister, TA}, title = {Effects of Beef Juice on Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel.}, journal = {Foodborne pathogens and disease}, volume = {17}, number = {4}, pages = {235-242}, doi = {10.1089/fpd.2019.2716}, pmid = {31809192}, issn = {1556-7125}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Food Contamination/*analysis ; Food Handling ; Food Microbiology ; Meat Products/*microbiology ; Shiga-Toxigenic Escherichia coli/*physiology ; Stainless Steel/*analysis ; }, abstract = {Shiga toxin-producing Escherichia coli (STEC) are a leading cause of foodborne illnesses worldwide, with beef and beef products as a common food reservoir. STEC strains may be present in beef-processing environments in the form of biofilms. The exudate of raw beef, also referred to as beef juice, has been identified as an important source of bacterial contamination on food-processing surfaces. This study applied beef juice as a food-based model to study its effects on biofilm formation of six STEC isolates on stainless steel. Crystal violet staining and cell enumeration demonstrated that beef juice inhibited the biofilm formation of strains O113, O145, and O91 up to 24 h at 22°C, but that biofilm increased (p < 0.05) thereafter over 72 h. Biofilms formed by O157, O111, and O45 were not affected by the addition of beef juice over the whole incubation period. Electron microscopy showed that the morphology of biofilm cells was altered and more extracellular matrix was produced with beef juice than with M9 medium. The present study demonstrated that beef juice residues on stainless steel can enhance biofilm formation of some STEC strains. Thorough and frequent cleaning of meat residues and exudate during meat production and handling is critical to reduce STEC biofilm formation even at 13°C.}, } @article {pmid31808241, year = {2020}, author = {Mu, YQ and Xie, TT and Zeng, H and Chen, W and Wan, CX and Zhang, LL}, title = {Streptomyces-derived actinomycin D inhibits biofilm formation via downregulating ica locus and decreasing production of PIA in Staphylococcus epidermidis.}, journal = {Journal of applied microbiology}, volume = {128}, number = {4}, pages = {1201-1207}, doi = {10.1111/jam.14543}, pmid = {31808241}, issn = {1365-2672}, support = {2017DB002//Innovating Project for Developing to the South in Xinjiang Production＆Construction Corps/ ; U1703236//National Science Foundation of China-Xinjiang joint Grant/ ; NCET-11-1071//New Century Excellent Talents in University/ ; 2017CB014//Microbial Resources Utilization Innovation Team in Key Field of Xinjiang Production ＆Construction Crops/ ; 2009JC07//Ph. D in Xinjiang Production＆Construction Corps/ ; 31260026//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Dactinomycin/metabolism/*pharmacology ; Down-Regulation/drug effects ; Humans ; Polysaccharides, Bacterial/genetics/*metabolism ; Staphylococcus epidermidis/*drug effects/genetics/metabolism/physiology ; Streptomyces/*metabolism ; }, abstract = {AIM: The objective of this study was to investigate the biofilm inhibitory activity of Streptomyces-derived actinomycin D against biofilm formation by Staphylococcus epidermidis.

METHODS AND RESULTS: The microtitre plate method and microscopy were used to detect the biofilm formation of S. epidermidis. And an attempt was made to detect the effect of actinomycin D on important biofilm components, exopolysaccharides (EPS) in S. epidermidis using precolumn derivation HPLC. Also cell surface hydrophobicities of S. epidermidis were assessed to explore action mechanisms. The qPCR was performed to demonstrate the genetic mechanisms of biofilm formation by S. epidermidis. Unlike other antibiotics, actinomycin D (1·5 μg ml[-1]) from Streptomyces luteus significantly inhibited biofilm formation by S. epidermidis. Additionally, it effectively inhibited S. epidermidis cells from adhering to glass slides. Actinomycin D downregulated ica locus and then the reduced polysaccharide intercellular adhesin production caused S. epidermidis cells to become less hydrophobic, thus supporting its anti-biofilm effect.

CONCLUSION: Streptomyces-derived actinomycin D is active in inhibiting the biofilm formation of S. epidermidis.

Actinomycin D can be used as a promising antibiofilm agent in inhibiting S. epidermidis biofilm formation. The study is also the first insight into how actinomycin D inhibited the biofilm formation of S. epidermidis. Actinomycin D could potentially be used to reduce the risk of biofilm-associated infections. Our study also suggests that the metabolites from Actinomycete strains keep further attention as potential antibiofilm agents against biofilm formation of S. epidermidis, even biofilm infections of the other bacteria.}, } @article {pmid31807847, year = {2020}, author = {Al-Mousawi, AH and Al-Kaabi, SJ and Albaghdadi, AJH and Almulla, AF and Raheem, A and Algon, AAA}, title = {Effect of Black Grape Seed Extract (Vitis vinifera) on Biofilm Formation of Methicillin-Resistant Staphylococcus aureus and Staphylococcus haemolyticus.}, journal = {Current microbiology}, volume = {77}, number = {2}, pages = {238-245}, pmid = {31807847}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Grape Seed Extract/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Phenols/pharmacology ; Staphylococcus haemolyticus/*drug effects ; }, abstract = {Grape seeds are considered one of the most important sources for phenolic and other compounds and is globally consumed for the biological value of its active ingredients. The increasing prevalence of Methicillin-resistant Staphylococcus aureus-related infections has become a very challenging health issue worldwide. This work aims at examining the antibacterial activity of alcoholic extract of black grape seeds (Vitis vinifera) against biofilm formation by Staphylococcus aureus and Staphylococcus haemolyticus. Staphylococcal bacterial isolates were first clinically confirmed using the VITEK-2compact system (ID and AST), and four isolates were selected depending on virulence and resistance to different types of antibiotics. The ability of S. aureus and S. haemolyticus isolates to form biofilm was examined using a standardized 96-well microtiter plate method. Furthermore, the effect of Moxifloxacin and Penicillin G with MIC, sub-MIC and sub-sub-MIC in preventing S. aureus and S. haemolyticus biofilm production, as well as that of the grape seed extract (180 mg/ml) were tested against biofilm formation. Our data indicate that all of the Staphylococcal bacterial isolates were able to produce biofilm which was prevented by the methanolic extracts of the crude seeds of Vitis vinifera rich in galloylated catechin esters of gallic acid. A significant (P < 0.001) synergistic effect between Penicillin G, Moxifloxacin with MIC, sub-MIC and sub-sub-MIC and that of the methanolic extract of Vitis vinifera (180 mg/ml) against bacterial biofilm formation was also detected. This report confirms the antibacterial activity of the methanolic extract of the black grape seeds.}, } @article {pmid31807362, year = {2019}, author = {Hu, WS and Nam, DM and Choi, JY and Kim, JS and Koo, OK}, title = {Anti-attachment, anti-biofilm, and antioxidant properties of Brassicaceae extracts on Escherichia coli O157:H7.}, journal = {Food science and biotechnology}, volume = {28}, number = {6}, pages = {1881-1890}, pmid = {31807362}, issn = {2092-6456}, abstract = {Bacteria can survive and persist in food processing environments by attachment and biofilm formation and transfer to food products, causing serious foodborne illness. In this study, we investigated natural substances that belong to the family Brassicaceae to determine whether they have potential anti-attachment activities against Escherichia coli O157:H7. The inhibition of biofilm formation was evaluated by crystal violet and resazurin assays at different stages of biofilm formation (initial attachment, biofilm formation, and after biofilm development) of E. coli O157:H7. The sessile cells were reduced to a range of 13.8-31.3% by young radish, radish, radish sprout, red cabbage, and kale extracts, and the viability was reduced to between 5.83 and 51.5%. The radical scavenging activities and the presence of polyphenolic compounds were compared. The presence of phenolic compounds such as gallic acid, caffeic acid, and phenylethyl ITC in the Brassicaceae family verified the potential use as a natural anti-biofilm substituent against E. coli O157:H7.}, } @article {pmid31807272, year = {2019}, author = {Hurley, CM and Hechtl, D and Ng, KC and McHugh, J and Sehgal, R and Regan, MC}, title = {Biofilm-sealed perforation of the gastric body: a rare sequela of gastric band erosion.}, journal = {Journal of surgical case reports}, volume = {2019}, number = {9}, pages = {rjz263}, pmid = {31807272}, issn = {2042-8812}, abstract = {Laparoscopic Adjustable Gastric Banding is one of the cardinal bariatric interventions and due to its early safety profile, became the mainstay. Major long-term complications of gastric banding include pouch-herniation-dilation and gastric erosion. A 59-year-old female presented to the emergency department with a 2-week history of progressive central abdominal pain and distention on a background history of a laparoscopic adjustable band insertion 11 years previously. Subsequent computed tomography demonstrated an intragastric band erosion. An exploratory laparotomy demonstrated a gastric band eroded through the stomach sealed by a biofilm. Secondary findings included small bowel ischemia and portal vein thrombosis. The gastric band was extracted, and the stomach was repaired. The ischemic small bowel was resected with primary anastomosis. The patient recovered uneventfully. Gastric band erosion should be considered in all patients presenting with abdominal pain and previous weight loss surgery. Prompt recognition may avoid fatal consequences.}, } @article {pmid31806326, year = {2020}, author = {Zhou, H and Xu, G}, title = {Biofilm characteristics, microbial community structure and function of an up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio.}, journal = {The Science of the total environment}, volume = {708}, number = {}, pages = {134422}, doi = {10.1016/j.scitotenv.2019.134422}, pmid = {31806326}, issn = {1879-1026}, mesh = {Anaerobiosis ; *Biofilms ; Bioreactors ; Extracellular Polymeric Substance Matrix ; *Microbiota ; Nitrogen ; RNA, Ribosomal, 16S ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {The biofilm characteristics, microbial community structure and function in a lab-scale up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio were investigated. Results showed that the TN removal rate of system reduced from 68.7% to 50.6% with COD/N ratio ranging from 10 to 3. Biofilm characteristics analysis indicated that the biomass, biofilm thickness, polysaccharide and protein contents in extracellular polymeric substance and dehydrogenase activity from biofilm in the UAF-BAF declined with the decrease of COD/N ratio. The biofilm structure visualized by confocal laser scanning microscopy displayed that the total cells and EPS content decreased as the COD/N ratio downshifted. 16S rRNA sequencing illustrated that Zoogloea and Pleomorphomonas were the major contributors to TN removal in the UAF, with dramatically decreasing abundance. Functional prediction indicated that the genes involved in nitrogen metabolism and nitrate reductase (EC 1.7.99.4) also decreased, which was responsible for the decrease of TN removal. This study provided insights into understanding of the biofilm structure and underlying ecological function in the UAF-BAF, which would help to regulate wastewater biofilm and improve process performance.}, } @article {pmid31806298, year = {2020}, author = {Jing, X and Yang, Y and Ai, Z and Chen, S and Zhou, S}, title = {Potassium channel blocker inhibits the formation and electroactivity of Geobacter biofilm.}, journal = {The Science of the total environment}, volume = {705}, number = {}, pages = {135796}, doi = {10.1016/j.scitotenv.2019.135796}, pmid = {31806298}, issn = {1879-1026}, mesh = {Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Geobacter ; Oxidation-Reduction ; Potassium Channel Blockers ; }, abstract = {Bacteria in biofilms are able to utilize potassium ion channel-mediated electrical signaling to achieve cell-cell communication. However, it remains unclear whether these signals play a role in Geobacter sp. when surrounded by an intense electric field. This study used a potassium channel blocker (tetraethylammonium, TEA) that interfered with the release of K[+] but not bacterial growth to demonstrate that potassium ion channel-mediated electrical signaling affected the formation and electroactivity of Geobacter sulfurreducens. The results showed that 5 mM TEA slowed the formation of Geobacter sulfurreducens biofilm, and the current density was ~50% lower than in the control. The electrochemical analyses showed that the electroactivity of the biofilms with TEA addition was inferior. In particular, the micrometer- scale biofilm with TEA exhibited fewer high current peaks, and the species of outermost groups that participated in the electron transfer in Geobacter sulfurreducens biofilms was different from the control. This work provides initial evidence to reveal the role of potassium channels in Geobacter sulfurreducens electroactive biofilms.}, } @article {pmid31805997, year = {2019}, author = {Davari Abad, E and Khameneh, A and Vahedi, L}, title = {Identification phenotypic and genotypic characterization of biofilm formation in Escherichia coli isolated from urinary tract infections and their antibiotics resistance.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {796}, pmid = {31805997}, issn = {1756-0500}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Cross-Sectional Studies ; Escherichia coli/drug effects/*genetics/isolation & purification ; Escherichia coli Infections/*microbiology/urine ; Genes, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Urinary Tract Infections/*microbiology/urine ; }, abstract = {OBJECTIVE: Urinary tract infections (UTIs) are the most common infectious diseases, and Escherichia coli is the most common pathogen isolated from patients with UTIs. The products of sfa, afa and foc genes are important for binding of the bacterium to urinary tract epithelium. Our aim was to investigate these genes in E. colis isolated from patients with UTIS. The frequencies of the genes were determined using PCR. Biofilm formation and antibiotic resistance rates were determined using microtiter plate and disk diffusion methods, respectively. The P < 0.05 was considered statistically significant.

RESULTS: The frequencies of sfa, afa and foc were 75.3%, 17.5% and 22.5%, respectively showing a significantly higher prevalence of the sfa gene. The most effective antibiotics against the E. colis were nitrofurantoin and amikacin. The highest microbial resistance rates were also observed against amoxicillin and ampicillin. Furthermore, 12.7%, 6.3%, 74.7% and 6.3% of the isolates showed strong, moderate, weak capacities and no connections to form biofilms, respectively. The expression of the sfa gene was significantly associated with forming strong biofilms. Regarding the variabilities in the characteristics of E. coli strains associated with UTIs, it seems reasonable to adjust diagnostic and therapeutic methods according to the regional microbial characteristics.}, } @article {pmid31805825, year = {2021}, author = {Cramer, M and Schelhorn, P and Kotzbauer, U and Tränckner, J}, title = {Degradation kinetics and COD fractioning of agricultural wastewaters from biogas plants applying biofilm respirometry.}, journal = {Environmental technology}, volume = {42}, number = {15}, pages = {2391-2401}, doi = {10.1080/09593330.2019.1701570}, pmid = {31805825}, issn = {1479-487X}, mesh = {Biofilms ; Biofuels ; Bioreactors ; Kinetics ; Sewage ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Stormwater runoff from agricultural silo facilities can be heavily polluted and needs to be treated before discharged. This study investigates biological treatability and kinetic constants of characteristic silo runoffs, applying attached growth systems. For this, respirometry measurements, typically applied in the activated sludge systems (ASM) as a suspended growth, were modified by using adapted biofilm carriers. This allows a determination of degradation kinetic of the biofilm system and a COD fractioning at the same time, which are fundamental values for the design of a full-scale plant. The developed respirometry method was compared with the state-of-the-art method using suspended growth systems and domestic wastewater. Results are comparable with the parameter of the ASM. As stormwater runoff is usually a mixture from different pollution sources, various, typically occurring substrates are investigated regarding degradation kinetics and COD fractions. Wastewater polluted with digestion residue and solid manure showed similar COD fractions as domestic wastewater with an inert fraction Si of 5-6% and a comparatively low rapidly degradable fraction SS of 21-27%. However, wastewater from corn or whole crop silage showed significant better degradation efficiencies and kinetics with an Si of 2-3% and a rapidly degradable fraction of 56-57%. As COD concentrations up to 5000 mg L[-1] for stormwater runoff and up to 60,000 mg L[-1] for silage effluent can be expected, the results not only show the necessity but also prove the feasibility of biological treatment of stormwater runoff from silo works and provide design parameters for adapted treatment systems.}, } @article {pmid31805672, year = {2019}, author = {Beklen, A and Torittu, A and Ihalin, R and Pöllänen, M}, title = {Aggregatibacter actinomycetemcomitans Biofilm Reduces Gingival Epithelial Cell Keratin Expression in an Organotypic Gingival Tissue Culture Model.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31805672}, issn = {2076-0817}, support = {126557, 265609, and 272960//Academy of Finland/ ; N/A//The Scientific and Technological Research Council of Turkey (TUBITAK)/ ; }, abstract = {Epithelial cells express keratins, which are essential for the structural integrity and mechanical strength of the cells. In the junctional epithelium (JE) of the tooth, keratins such as K16, K18, and K19, are expressed, which is typical for non-differentiated and rapidly dividing cells. The expression of K17, K4, and K13 keratins can be induced by injury, bacterial irritation, smoking, and inflammation. In addition, these keratins can be found in the sulcular epithelium and in the JE. Our aim was to estimate the changes in K4, K13, K17, and K19 expression in gingival epithelial cells exposed to Aggregatibacter actinomycetemcomitans. An organotypic gingival mucosa and biofilm co-culture was used as a model system. The effect of the biofilm after 24 h was assessed using immunohistochemistry. The structure of the epithelium was also studied with transmission electron microscopy (TEM). The expression of K17 and K19, as well as total keratin expression, decreased in the suprabasal layers of epithelium, which were in close contact with the A. actinomycetemcomitans biofilm. The effect on keratin expression was biofilm specific. The expression of K4 and K13 was low in all of the tested conditions. When stimulated with the A. actinomycetemcomitans biofilm, the epithelial contact site displayed a thick necrotic layer on the top of the epithelium. The A. actinomycetemcomitans biofilm released vesicles, which were found in close contact with the epithelium. After A. actinomycetemcomitans irritation, gingival epithelial cells may lose their resistance and become more vulnerable to bacterial infection.}, } @article {pmid31805671, year = {2019}, author = {Desai, S and Sanghrajka, K and Gajjar, D}, title = {High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31805671}, issn = {2076-0817}, abstract = {Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a "priority pathogen". Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.}, } @article {pmid31800863, year = {2019}, author = {Fidalgo, TKDS and Americano, G and Medina, D and Athayde, G and Letieri, ADS and Maia, LC}, title = {Adhesiveness of bulk-fill composite resin in permanent molars submitted to Streptococcus mutans biofilm.}, journal = {Brazilian oral research}, volume = {33}, number = {}, pages = {e111}, doi = {10.1590/1807-3107bor-2019.vol33.0111}, pmid = {31800863}, issn = {1807-3107}, mesh = {Adhesiveness ; Biofilms/*drug effects ; Composite Resins/*chemistry ; Dental Bonding/*methods ; Dental Caries ; Dental Enamel/drug effects ; Dental Leakage ; Dental Restoration, Permanent/methods ; Humans ; Materials Testing ; Reproducibility of Results ; Statistics, Nonparametric ; Streptococcus mutans/*drug effects ; Surface Properties ; Tensile Strength/drug effects ; Time Factors ; }, abstract = {The aim of the present study was to evaluate the microtensile bond strength and the microleakage of a bulk-fill composite resin compared with a conventional incremental composite resin, in permanent molars and under cariogenic challenge using a Streptococcus mutans model. Permanent human third molars (n = 60) with an occlusal cavity of 5×3×2 mm were randomly allocated into four subgroups of restorative treatments: conventional composite resin with (n = 15) and without (n = 15) cariogenic challenge (Z350-E and Z350-C experimental and control groups, respectively), and bulk-fill composite resin with (n = 15) and without (n = 15) cariogenic challenge (Bulk Fill-E and Bulk Fill-C, respectively). Ten specimens from each subgroup were submitted to microtensile strength, and 5, to microleakage. The cariogenic challenge was conducted using the Streptococcus mutans strain (ATCC) for 7 days. The stickers obtained (1 × 1 × 2 mm) were submitted to a microtensile strength test, followed by classification of the fracture mode. Microleakage was performed using a scoring system. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Filtek Z350 XT resin presented higher microtensile bond strength than Bulk Fill resin without (19.02 ± 4.90 and 8.76 ± 3.94MPa, respectively; p < 0.001) and with cariogenic challenge (22.69 ± 7.86 and 13.31 ± 3.38MPa, respectively; p < 0.02). Z350-C and Bulk Fill-C resins presented a higher prevalence of mixed fractures (23 and 14%, respectively) in the specimens submitted to cariogenic challenge than those of the control groups, whereas microleakage was similar (p = 0.85). The conventional composite resin had higher microtensile bond strength than the bulk-fill resin, but both resin types had similar adhesion quality and microfiltration scores.}, } @article {pmid31799432, year = {2019}, author = {Suleiman, M and Schröder, C and Kuhn, M and Simon, A and Stahl, A and Frerichs, H and Antranikian, G}, title = {Microbial biofilm formation and degradation of octocrylene, a UV absorber found in sunscreen.}, journal = {Communications biology}, volume = {2}, number = {}, pages = {430}, pmid = {31799432}, issn = {2399-3642}, mesh = {Acrylates/*chemistry/*pharmacology ; Biofilms/*drug effects/radiation effects ; Chromatography, Liquid ; Gas Chromatography-Mass Spectrometry ; Molecular Structure ; Sunscreening Agents/*chemistry/*pharmacology ; Tandem Mass Spectrometry ; Ultraviolet Rays ; }, abstract = {Octocrylene is a widely used synthetic UV absorber of sunscreens and found in several environments. Ecological consequences of the accumulation of UV filters are widely discussed. This is the first report revealing the microbial potential to transform octocrylene. A microbial community comprising four bacterial species was enriched from a landfill site using octocrylene as carbon source. From these microorganisms Mycobacterium agri and Gordonia cholesterolivorans were identified as most potent applying a new "reverse discovery" approach. This relies on the possibility that efficient strains that are already isolated and deposited can be identified through enrichment cultures. These strains formed massive biofilms on the octocrylene droplets. GC-MS analysis after cultivation for 10 days with M. agri revealed a decrease in octocrylene concentration of 19.1%. LC-MS/MS analysis was utilized in the detection and quantification of transformation products of octocrylene. M. agri thus represents an ideal candidate for bioremediation studies with octocrylene and related compounds.}, } @article {pmid31798802, year = {2018}, author = {Kıvanç, SA and Arık, G and Akova-Budak, B and Kıvanç, M}, title = {Biofilm forming capacity and antibiotic susceptibility of Staphylococcus spp. with the icaA/icaD/bap genotype isolated from ocular surface of patients with diabetes.}, journal = {Malawi medical journal : the journal of Medical Association of Malawi}, volume = {30}, number = {4}, pages = {243-249}, pmid = {31798802}, issn = {1995-7270}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Diabetes Complications/epidemiology ; Diabetes Mellitus/epidemiology ; Drug Resistance, Bacterial ; Eye Infections, Bacterial/*microbiology ; Genes, Bacterial/genetics/physiology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Phenotype ; Polymerase Chain Reaction ; Retrospective Studies ; Staphylococcal Infections/diagnosis/*microbiology ; Staphylococcus/*drug effects/genetics/isolation & purification ; }, abstract = {INTRODUCTION: Bacterial biofilm is an exopolysaccharide matrix that is produced by bacteria while they adhere on abiotic or biotic surfaces. The bacteria living in this matrix are more resistant to antibiotics than planctonic bacteria. The biofilm formation property of the bacteria is determined by genes; and this is related to virulence of the microorganism. In ophthalmology, biofilms form especially on abiotic surfaces such as silicon tubes, contact lenses, intraocular lenses etc.

AIM: Our aim was to investigate genotypic and phenotypic structures of biofilms that are produced by Staphylococcus spp., which was obtained from the eyes of diabetic patients and determine the effect on antibiotic susceptibility.

METHODS: The study group was comprised with 83 isolates from diabetic patients and 21 isolates from non-diabetic patients. Presumptive isolates were detected and confirmed by a microbial identification system VITEK II. Automated EcoRI Ribotyping was performed. Biofilm production was detected by Congo Red Agar Plate and Microtiter Plate Assay. Disc diffusion method was used for determination of antibiotic susceptibility of isolates.

RESULTS: Out of the 83 isolates from diabetic patients, 25 were weakly (30%), 20 were moderately (24%), and 25 were strongly (30%) biofilm positive. Seven isolates of S. aureus, 11 isolates of S.epidermidis, 2 isolates of S. warneri, 3 isolates of S.hominis, and 2 isolates of S.lugdunensis were identified as strong biofilm producers. Out of the 83 Staphylococcus isolates, 37 were cefuroxime, 18 ciprofloxacin, 11 vancomycin, 12 gatifloxacin, and 18 moxifloxacin resistant. In total, 37 strains were resistant to three or more antibiotics. There was a statistically significant relation between biofilm formation and multidrug resistance (against three or more antibiotics, p<0.001). In nondiabetic patients, 15(71%) isolates were non adherent or weakly adherent, and 2(10%) were strongly adherent biofilm positive.

CONCLUSION: In conclusion, bacterial conjunctival flora of patients with diabetes is likely to produce biofilm. Biofilm formation is associated with multidrug rsistance in patients with diabetes.}, } @article {pmid31798554, year = {2019}, author = {Soares, A and Roussel, V and Pestel-Caron, M and Barreau, M and Caron, F and Bouffartigues, E and Chevalier, S and Etienne, M}, title = {Understanding Ciprofloxacin Failure in Pseudomonas aeruginosa Biofilm: Persister Cells Survive Matrix Disruption.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2603}, pmid = {31798554}, issn = {1664-302X}, abstract = {Biofilms are commonly recalcitrant to antibiotics, through incompletely elucidated mechanisms such as tolerance and persistence. We aimed at investigating how a Pseudomonas aeruginosa biofilm escapes ciprofloxacin treatment. P. aeruginosa PA14 in vitro mature biofilms were challenged with supra-MIC ciprofloxacin concentrations. Cell viability was quantified by fluorescein diacetate assay. Population dynamics were determined by counts of surviving culturable cells. Biofilms were analyzed using confocal laser scanning microscopy (CLSM), and the expression of genes involved in stringent response, toxin-antitoxin HigB/HigA, and type 3 secretion system (T3SS) was quantified by RT-qPCR in untreated and treated biofilms. Ciprofloxacin exposure resulted in an initial reduction of bacterial counts following a biphasic time-kill curve. After 24 h of treatment, the overall cell activity and the density of culturable cells significantly decreased as compared to untreated biofilm. No resistant mutant was isolated among the <1% surviving cells. Phenotypic adaptation toward persistence appeared to start after only 1 h of antibiotic exposure, by an overexpression of the genes involved in stringent response and in the toxin-antitoxin system, whereas the expression of genes encoding for the T3SS remained unchanged. After 4 h of ciprofloxacin exposure, stringent response genes returned to their basal level of expression. After a prolonged ciprofloxacin exposure, a deep alteration in the matrix structure that became thinner and lost mushroom-like aggregates was observed, in relation with reduced biovolumes of exopolysaccharides and extracellular DNA. These results support that ciprofloxacin might first induce the bacterial killing of most bacterial cells, but simultaneously activate stringent response mechanisms contributing to the switch of a subpopulation toward a persister phenotype. Once the persister phenotype is expressed, and despite an unexpected alteration of the biofilm matrix, ciprofloxacin fails to eradicate biofilm.}, } @article {pmid31797835, year = {2019}, author = {Thomas, AR and Mani, R and Reddy, TV and Ravichandran, A and Sivakumar, M and Krishnakumar, S}, title = {Evaluation of the Antibacterial Efficiency of a Combination of 1% Alexidine and Sodium Hypochlorite on Enterococcus faecalis Biofilm Models: An In Vitro Study.}, journal = {The journal of contemporary dental practice}, volume = {20}, number = {9}, pages = {1090-1094}, pmid = {31797835}, issn = {1526-3711}, mesh = {Anti-Bacterial Agents ; Biguanides ; Biofilms ; Dentin ; *Enterococcus faecalis ; Humans ; India ; Microscopy, Confocal ; Root Canal Irrigants ; *Sodium Hypochlorite ; }, abstract = {AIM: The aim of the study was to assess the antibacterial efficiency of a combination of 1% alexidine (ALX) and 5.25% sodium hypochlorite (NaOCl) against E. faecalis biofilm using a confocal scanning electron microscopy.

MATERIALS AND METHODS: An estimated 120 human root dentin disks were prepared, sterilized, and inoculated with E. faecalis strain (ATCC 29212) to develop a 3-weeks-old biofilm. The dentin discs were exposed to group I-control group: 5.25% sodium hypochlorite (NaOCl) (n = 20); group II-1% ALX + 5.25% NaOCl (n = 40); group III-1% alexidine (ALX) (n = 40) (Sigma-Aldrich, Mumbai, India); group IV-negative control: saline (n = 20). After exposure, the dentin disks were stained with the fluorescent live/dead dye and evaluated with a confocal scanning electron microscope to calculate the proportion of dead cells. Statistical analysis was done using the Kruskal-Wallis and Mann-Whitney U test (p < 0.05).

RESULTS: The maximum proportion of dead cells were seen in the groups treated with the combination of 1% ALX + 5.25% NaOCl (94.89%) and in the control group 5.25% NaOCl (93.14%). The proportion of dead cells presented in the 1% ALX group (51.79%) and negative control group saline (15.10%) were comparatively less.

CONCLUSION: The antibacterial efficiency of a combination of 1% ALX and 5.25% NaOCl was more effective when compared with 1% ALX alone.

CLINICAL SIGNIFICANCE: Alexidine at 1% could be used as an alternative endodontic irrigant to chlorhexidine, as alexidine does not form any toxic precipitates with sodium hypochlorite. The disinfection regimen comprising a combination of 1% ALX and 5.25% NaOCl is effective in eliminating E. faecalis biofilms.}, } @article {pmid31797512, year = {2020}, author = {Wettstadt, S}, title = {Breaking free from home: biofilm dispersal by a glycosidase from Desulfovibrio vulgaris.}, journal = {Environmental microbiology}, volume = {22}, number = {2}, pages = {557-558}, doi = {10.1111/1462-2920.14883}, pmid = {31797512}, issn = {1462-2920}, support = {BIO2017-83763-P//Consejo Superior de Investigaciones Científicas/International ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Biofilms/drug effects/*growth & development ; Desulfovibrio vulgaris/drug effects/enzymology/*metabolism ; Glycoside Hydrolases/*metabolism ; Metals/metabolism ; }, } @article {pmid31797056, year = {2020}, author = {Cao, Y and Yin, H and Wang, W and Pei, P and Wang, Y and Wang, X and Jiang, J and Luo, SZ and Chen, L}, title = {Killing Streptococcus mutans in mature biofilm with a combination of antimicrobial and antibiofilm peptides.}, journal = {Amino acids}, volume = {52}, number = {1}, pages = {1-14}, doi = {10.1007/s00726-019-02804-4}, pmid = {31797056}, issn = {1438-2199}, support = {PYBZ1812//Research projects on biomedical transformation of China-Japan Friendship Hospital/ ; PYBZ1815//Research projects on biomedical transformation of China-Japan Friendship Hospital/ ; 2017YFF0205402//National Key Research and Development Program/ ; 21562035//National Natural Science Foundation of China/ ; 21672019//National Natural Science Foundation of China/ ; 21402006//National Natural Science Foundation of China/ ; 91853116//National Natural Science Foundation of China/ ; XK1802-8//Fundamental Research Funds for the Central Universities/ ; PYBZ1711//Fundamental Research Funds for the Central Universities/ ; ZZ1702//Fundamental Research Funds for the Central Universities/ ; XK1701//Fundamental Research Funds for the Central Universities/ ; }, mesh = {Anti-Bacterial Agents/adverse effects/therapeutic use ; Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; Streptococcus mutans/*drug effects/pathogenicity ; }, abstract = {Biofilm poses a serious challenge for the treatment of bacterial infections, as it endows bacteria a pronounced resistance to traditional antibiotics. Antimicrobial peptides (AMPs) are considered potential substitutes for antibiotics. Combinational use of AMPs with other compounds to exert antibiofilm effects has been proved to be an effective means to reduce their toxicity and maximize their antimicrobial activity. However, the combination of various AMPs with different action mechanisms is rarely investigated. A newly designed lytic AMP ZXR-2.3 combined with antibiofilm peptide IDR-1018 or KT2 was tested for the antibiofilm effect on mature Streptococcus mutans biofilms. In general, the combination of ZXR-2.3 + IDR-1018 displayed synergistic effect on both biofilm eradication and bacterial killing, while ZXR-2.3 + KT2 showed no obvious synergism. The confocal images of preformed S. mutans biofilms confirmed the effective bactericidal activity of ZXR-2.3 + IDR-1018. A tube system was applied to investigate the biofilm infection under a flow of medium and SEM images indicated the biofilm disruption and bacterial killing effects of ZXR-2.3 + IDR-1018. Quantitative RT-PCR analysis showed that IDR-1018 induced dramatic changes in the mRNA expressions of the quorum sensing (QS) related genes comC, comD, vicR, and vicK of S. mutans in mature biofilms, whereas the other peptides and ciprofloxacin did not cause obvious changes in these genes. This might explain the better synergism of ZXR-2.3 and IDR-1018. The results of this study provide a potential application using the combination of different AMPs in the treatment of mature biofilm infection.}, } @article {pmid31796849, year = {2019}, author = {Whelan, MVX and Ardill, L and Koide, K and Nakajima, C and Suzuki, Y and Simpson, JC and Ó Cróinín, T}, title = {Acquisition of fluoroquinolone resistance leads to increased biofilm formation and pathogenicity in Campylobacter jejuni.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {18216}, pmid = {31796849}, issn = {2045-2322}, support = {105343/Z/14/Z//Wellcome Trust (Wellcome)/International ; }, mesh = {Biofilms/*growth & development ; Campylobacter Infections/*drug therapy/microbiology ; Campylobacter jejuni/genetics/*pathogenicity ; DNA Gyrase/genetics/metabolism ; DNA, Superhelical/drug effects/metabolism ; Drug Resistance, Bacterial/drug effects/*genetics ; Fluoroquinolones/*pharmacology/therapeutic use ; HT29 Cells ; Humans ; Microbial Sensitivity Tests ; Point Mutation/drug effects ; Virulence/genetics ; }, abstract = {The World Health Organization has listed C. jejuni as one of 12 microorganisms on a global priority list for antibiotic resistance due to a rapid increase in strains resistant to fluoroquinolone antibiotics. This fluoroquinolone resistance is conferred through a single point mutation in the QRDR region within the gyrA gene known to be involved in DNA supercoiling. We have previously revealed that changes in DNA supercoilikng play a major role in the regulation of virulence in C. jejuni with relaxation of DNA supercoiling associated with increased attachment to and invasion of human epithelial cells. The aim of this study was to investigate whether fluoroquinolone resistant strains of C. jejuni displayed altered supercoiling associated phenotypes. A panel of fluoroquinolone resistant mutants were derived and shown to have a greater ability to form viable biofilms under aerobic conditions, invade epithelial cells and promote virulence in the Galleria mellonella model of infection. We thus report for the first time that fluoroquinolone resistance in C. jejuni is associated with an increase in virulence and the ability to form viable biofilms in oxygen rich environments. These altered phenotypes likely play a critical role in the continued increase in fluoroquinolone resistance observed for this important pathogen.}, } @article {pmid31794939, year = {2020}, author = {Wang, J and Liu, Q and Li, X and Ma, S and Hu, H and Wu, B and Zhang, XX and Ren, H}, title = {In-situ monitoring AHL-mediated quorum-sensing regulation of the initial phase of wastewater biofilm formation.}, journal = {Environment international}, volume = {135}, number = {}, pages = {105326}, doi = {10.1016/j.envint.2019.105326}, pmid = {31794939}, issn = {1873-6750}, mesh = {Acyl-Butyrolactones ; Bacteria ; *Biofilms ; *Quorum Sensing ; *Wastewater ; }, abstract = {Initial attachment plays an important role in biofilm formation in wastewater treatment processes. However, the initial attachment process mediated by N-acyl-homoserine lactones (AHLs) is difficult to be fully understood due to the lack of non-invasive and on-line investigation techniques. In this study, the AHL-regulated wastewater biofilm attachment was quantified using ultrasonic time-domain reflectometry (UTDR) as an in-situ and non-invasive monitoring technique. Results demonstrated that the reversible adhesion time in municipal and industrial wastewaters was significantly decreased in the presence of exogenous AHLs. Biofilm thickness in municipal and industrial wastewaters increased significantly with the addition of exogenous AHLs. Also, the addition of acylase delayed the initial biofilm formation (lengthened reversible adhesion time and decreased biofilm thickness and density). Compared with biofilm behavior in the presence of low concentrations of AHLs (4.92 ± 0.17 μg/L), both reversible adhesion time and biofilm thickness were not significantly increased (p > 0.05) with an increase in AHL concentration (9.75 ± 0.41 μg/L). Furthermore, the addition of exogenous AHLs resulted in significant changes in the attached bacterial community structures, in which both QS and quorum-quenching (QQ) bacteria were stimulated. The current work presents an effective approach to in-situ monitoring of the regulation of AHL-mediated QS in the initial attachment of biofilms, especially in the reversible adhesion process, which may provide a potential strategy to facilitate biofilm establishment in wastewater treatment processes.}, } @article {pmid31794255, year = {2020}, author = {Wang, W and Wang, L and Su, J and Xu, Z}, title = {Antibiotic Susceptibility, Biofilm-Forming Ability, and Incidence of Class 1 Integron of Salmonella spp., Escherichia coli, and Staphylococcus aureus Isolated from Various Foods in a School Canteen in China.}, journal = {Foodborne pathogens and disease}, volume = {17}, number = {4}, pages = {269-275}, doi = {10.1089/fpd.2019.2694}, pmid = {31794255}, issn = {1556-7125}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms/growth & development ; Chickens ; China/epidemiology ; Drug Resistance, Bacterial ; Escherichia coli/drug effects/*isolation & purification/physiology ; Food Contamination/*analysis ; *Food Microbiology ; Food Services ; Foodborne Diseases/epidemiology/microbiology ; Humans ; Incidence ; Integrons ; Meat/microbiology ; Microbial Sensitivity Tests ; Salmonella/drug effects/*isolation & purification/physiology ; School Health Services ; Schools ; Staphylococcus aureus/drug effects/*isolation & purification/physiology ; Swine ; Vegetables/microbiology ; }, abstract = {In recent years, the food poisoning incidents from school canteens have aroused widespread concern in China. Microbial contamination to the foods is the main factor responsible for these food poisoning events. In this study, identification of microbial pathogens including Salmonella spp., Escherichia coli, and Staphylococcus aureus in samples (frozen pork, fresh pork, fresh chicken, and different fresh vegetables) of a school canteen in China during 2017 to 2018 was performed. The antibiotic susceptibility pattern, class 1 integron, and biofilm formation ability of the isolated pathogens were also investigated. In total, 96 strains were isolated (32 Salmonella spp., 32 E. coli, and 32 S. aureus). The antibiogram study results demonstrated that 61.5% strains were found resistant to at least one type of antibiotics, and 17.7% were resistant to three or more antibiotics. In addition, 31.3% strains possessed class 1 integron. Among the integron-positive isolates, 38.9% Salmonella spp. and 87.5% E. coli contained ∼800 or/and 1500 bp size gene cassette within the integrons. However, four S. aureus strains possessing class 1 integron without gene cassette were found. Although none of the isolated strains were found strong biofilm producer, 44.8% were found to have weak or moderate biofilm formation ability. Despite biofilm formation ability or not, the Salmonella spp. containing positive class 1 integron showed significant resistance to cefazolin and gentamicin. In addition, class 1 integron-positive E. coli isolates having the biofilm formation ability hardly showed sensitive to four antibiotics, such as amikacin, amoxicillin-clavulanate, cefazolin, and gentamicin. Therefore, it is necessary to reduce the prevalence of antibiotic resistance gene cassettes containing antibiotic resistance genes by the prudent use of antibiotics in livestock farms, and the improvement of food processing and storage environment.}, } @article {pmid31790796, year = {2020}, author = {Ghosh, C and Bhowmik, J and Ghosh, R and Das, MC and Sandhu, P and Kumari, M and Acharjee, S and Daware, AV and Akhter, Y and Banerjee, B and De, UC and Bhattacharjee, S}, title = {The anti-biofilm potential of triterpenoids isolated from Sarcochlamys pulcherrima (Roxb.) Gaud.}, journal = {Microbial pathogenesis}, volume = {139}, number = {}, pages = {103901}, doi = {10.1016/j.micpath.2019.103901}, pmid = {31790796}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Molecular Structure ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/physiology ; Triterpenes/chemistry/*pharmacology ; Urticaceae/*chemistry ; }, abstract = {Formation of biofilm is the major cause of Pseudomonas aeruginosa associated pathological manifestations in the urinary tract, respiratory system, gastrointestinal tract, skin, soft tissues etc. Triterpenoid group of compounds have shown their potential in reducing planktonic and biofilm form of bacteria. Sarcochlamys pulcherrima (Roxb.) Gaud. is an ethnomedicinal plant traditionally used for its anti-microbial and anti-inflammatory property. In the present study two triterpenoids, have been isolated from this plant, characterised and evaluated for their antibacterial and antibiofilm potential against P. aeruginosa. Compounds were characterised as 2α, 3β, 19α-trihydroxy-urs-12-ene-28-oic acid (Tormentic acid) and 2α, 3β, 23-trihydroxyurs-12-ene-28-oic acid (23-hydroxycorosolic acid) through spectroscopic studies viz. infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS). Depolarization of bacterial membrane and zone of inhibition studies revealed that both the compounds inhibited the growth of planktonic bacteria. Compounds were also found to inhibit the formation of P. aeruginosa biofilm. Inhibition of biofilm found to be mediated through suppressed secretion of pyoverdin, protease and swarming motility of P. aeruginosa. Gene expression study, in silico binding analysis, in vivo bacterial load and tissue histology observations also supported the antibiofilm activity of both the compounds. In vitro and in vivo study showed that both compounds were non-toxic. The study has explored the antibacterial and antibiofilm effect of two triterpenes isolated for the first time from S. pulcherrima.}, } @article {pmid31790395, year = {2019}, author = {Hegde, S and Nilyanimit, P and Kozlova, E and Anderson, ER and Narra, HP and Sahni, SK and Heinz, E and Hughes, GL}, title = {CRISPR/Cas9-mediated gene deletion of the ompA gene in symbiotic Cedecea neteri impairs biofilm formation and reduces gut colonization of Aedes aegypti mosquitoes.}, journal = {PLoS neglected tropical diseases}, volume = {13}, number = {12}, pages = {e0007883}, pmid = {31790395}, issn = {1935-2735}, support = {R21 AI124452/AI/NIAID NIH HHS/United States ; R21 AI129507/AI/NIAID NIH HHS/United States ; R21 AI138074/AI/NIAID NIH HHS/United States ; }, mesh = {Aedes/*microbiology ; Animals ; Bacterial Outer Membrane Proteins/*genetics ; Biofilms/*growth & development ; CRISPR-Associated Protein 9/metabolism ; Clustered Regularly Interspaced Short Palindromic Repeats ; Enterobacteriaceae/*genetics/growth & development ; Gastrointestinal Tract/*microbiology ; *Gene Deletion ; *Gene Knockout Techniques ; Symbiosis ; }, abstract = {BACKGROUND: Symbiotic bacteria are pervasive in mosquitoes and their presence can influence many host phenotypes that affect vectoral capacity. While it is evident that environmental and host genetic factors contribute in shaping the microbiome of mosquitoes, we have a poor understanding regarding how bacterial genetics affects colonization of the mosquito gut. The CRISPR/Cas9 gene editing system is a powerful tool to alter bacterial genomes facilitating investigations into host-microbe interactions but has yet to be applied to insect symbionts.

To investigate the role of bacterial genetic factors in mosquito biology and in colonization of mosquitoes we used CRISPR/Cas9 gene editing system to mutate the outer membrane protein A (ompA) gene of a Cedecea neteri symbiont isolated from Aedes mosquitoes. The ompA mutant had an impaired ability to form biofilms and poorly infected Ae. aegypti when reared in a mono-association under gnotobiotic conditions. In adult mosquitoes, the mutant had a significantly reduced infection prevalence compared to the wild type or complement strains, while no differences in prevalence were seen in larvae, suggesting genetic factors are particularly important for adult gut colonization. We also used the CRISPR/Cas9 system to integrate genes (antibiotic resistance and fluorescent markers) into the symbionts genome and demonstrated that these genes were functional in vitro and in vivo.

CONCLUSIONS/SIGNIFICANCE: Our results shed insights into the role of ompA gene in host-microbe interactions in Ae. aegypti and confirm that CRISPR/Cas9 gene editing can be employed for genetic manipulation of non-model gut microbes. The ability to use this technology for site-specific integration of genes into the symbiont will facilitate the development of paratransgenic control strategies to interfere with arboviral pathogens such Chikungunya, dengue, Zika and Yellow fever viruses transmitted by Aedes mosquitoes.}, } @article {pmid31788680, year = {2019}, author = {Patenall, BL and Williams, GT and Gwynne, L and Stephens, LJ and Lampard, EV and Hathaway, HJ and Thet, NT and Young, AE and Sutton, MJ and Short, RD and Bull, SD and James, TD and Sedgwick, AC and Jenkins, ATA}, title = {Reaction-based indicator displacement assay (RIA) for the development of a triggered release system capable of biofilm inhibition.}, journal = {Chemical communications (Cambridge, England)}, volume = {55}, number = {100}, pages = {15129-15132}, doi = {10.1039/c9cc07759f}, pmid = {31788680}, issn = {1364-548X}, mesh = {Anthraquinones/*chemistry/pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Hydrogels/chemistry/pharmacology ; Hydrogen Peroxide/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects ; Solubility ; }, abstract = {Here, a reaction-based indicator displacement hydrogel assay (RIA) was developed for the detection of hydrogen peroxide (H2O2) via the oxidative release of the optical reporter Alizarin Red S (ARS). In the presence of H2O2, the RIA system displayed potent biofilm inhibition for Methicillin-resistant Staphylococcus aureus (MRSA), as shown through an in vitro assay quantifying antimicrobial efficacy. This work demonstrated the potential of H2O2-responsive hydrogels containing a covalently bound diol-based drug for controlled drug release.}, } @article {pmid31787947, year = {2019}, author = {Chen, P and Wang, JJ and Hong, B and Tan, L and Yan, J and Zhang, Z and Liu, H and Pan, Y and Zhao, Y}, title = {Characterization of Mixed-Species Biofilm Formed by Vibrio parahaemolyticus and Listeria monocytogenes.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2543}, pmid = {31787947}, issn = {1664-302X}, abstract = {Mixed-species biofilms are the predominant form of biofilms found in nature. Research on biofilms have typically concentrated on single species biofilms and this study expands the horizon of biofilm research, where the characterization and dynamic changes of mono and mixed-species biofilms formed by the pathogens, Vibrio parahaemolyticus and Listeria monocytogenes were investigated. Compared to mono-species biofilm, the biomass, bio-volume, and thickness of mixed-species biofilms were significantly lower, which were confirmed using crystal violet staining, confocal laser scanning microscopy and scanning electron microscopy. Further experimental analysis showed these variations might result from the reduction of bacterial numbers, the down-regulation of biofilm-regulated genes and loss of metabolic activity in mixed-species biofilm. In addition, V. parahaemolyticus was located primarily on the surface layers of the mixed-species biofilms thus accruing competitive advantage. This competitive advantage was evidenced in a higher V. parahaemolyticus population density in the mixed-species biofilms. The adhesion to surfaces of the mixed-species biofilms were also reduced due to lower concentrations of extracellular polysaccharide and protein when the structure of the mixed-species was examined using Raman spectral analysis, phenol-sulfuric acid method and Lowry method. Furthermore, the minimum biofilm inhibitory concentration to antibiotics obviously decreased when V. parahaemolyticus co-exited with L. monocytogenes. This study firstly elucidated the interactive behavior in biofilm development of two foodborne pathogens, and future studies for biofilm control and antibiotic therapy should take into account interactions in mixed-species biofilms.}, } @article {pmid31787943, year = {2019}, author = {Govaert, M and Smet, C and Walsh, JL and Van Impe, JFM}, title = {Dual-Species Model Biofilm Consisting of Listeria monocytogenes and Salmonella Typhimurium: Development and Inactivation With Cold Atmospheric Plasma (CAP).}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2524}, pmid = {31787943}, issn = {1664-302X}, abstract = {Most environmental biofilms contain a variety of species. These species can establish cooperative and competitive interactions, possibly resulting in an increase or a decrease in antimicrobial resistance. Therefore, results obtained following inactivation of single-species biofilms by means of different technologies (e.g., Cold Atmospheric Plasma, CAP) should be validated for multi-species biofilms. First, a strongly adherent and mature Listeria monocytogenes and S. Typhimurium dual-species biofilm was developed by altering different incubation conditions, i.e., growth medium, incubation temperature, inoculum ratio of L. monocytogenes and S. Typhimurium cells, and incubation time. Adherence and maturity were quantified by means of optical density measurements and viable plate counts, respectively. Secondly, both the (1 day old) reference biofilm and a more mature 7 days old biofilm were treated for different CAP treatment times (0-30 min). Viable plate counts were again used to determine the (remaining) cell density. For both the biofilm development and inactivation, predictive models were applied to describe the growth/inactivation kinetics. Finally, the kinetics of the [1 and 7 day(s) old] dual-species biofilms were compared with those obtained for the corresponding single-species biofilms. Results implied that a strongly adherent and mature reference dual-species biofilm was obtained following 24 h of incubation at 25°C using 20-fold diluted TSB and an inoculum ratio of 1:1. Main observations regarding CAP inactivation were: (i) the dual-species biofilm age had no influence on the CAP efficacy, although a longer treatment time was required for the oldest biofilm, (ii) for the 1 day old biofilms, CAP treatment became less efficient for S. Typhimurium inactivation when this species was part of the dual-species biofilm, while L. monocytogenes inactivation was not influenced by the biofilm type, and (iii) for the 7 days old biofilms, CAP inactivation of both species became more efficient when they were part of the dual-species biofilms. It can be concluded that the efficacy of the CAP treatment is altered when cells become part of a dual-species biofilm, which is quite important with respect to a possible application of CAP for biofilm inactivation within the food industry.}, } @article {pmid31787937, year = {2019}, author = {Supa-Amornkul, S and Mongkolsuk, P and Summpunn, P and Chaiyakunvat, P and Navaratdusit, W and Jiarpinitnun, C and Chaturongakul, S}, title = {Alternative Sigma Factor B in Bovine Mastitis-Causing Staphylococcus aureus: Characterization of Its Role in Biofilm Formation, Resistance to Hydrogen Peroxide Stress, Regulon Members.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2493}, pmid = {31787937}, issn = {1664-302X}, abstract = {This study examines treatments of the bacterial pathogen Staphylococcus aureus, namely, in the context of its being a major cause of subclinical bovine mastitis. Such infections caused by S. aureus among dairy cows are difficult to detect and can easily become chronic, leading to reduced productivity and large losses for dairy manufacturers. In this study, the role of alternative sigma factor B (σ[B]), which has been shown to be a global regulator for S. aureus infections, was explored in a mastitis-causing S. aureus strain, RF122. For comparison with the wild-type strain, a sigB null (ΔsigB) mutant was constructed and analyzed for its phenotypes and transcriptome. Our study found that σ[B] is essential for biofilm formation as the ΔsigB mutant strain produced significantly less biofilm than did the wild-type strain at 48 h. σ[B] is involved in response to H2O2 stress. However, σ[B] plays a minor or no role in resistance to antiseptics (e.g., povidone-iodine and chlorhexidine), resistance to tested antibiotics, hemolysin activity, and invasion ability. RNA sequencing identified 225 σ[B]-dependent genes, of which 171 are positively regulated and 54 are negatively regulated. The identified genes are involved in stress response, pathogenesis, and metabolic mechanisms. Quantitative TaqMan RT-PCR was performed to verify the RNA sequencing results; i.e., σ[B] is a positive regulator for asp23, sarA, katA, yabJ, sodA, SAB2006c, and nrdD expressions. In the RF122 strain, σ[B] plays a role in biofilm formation, general stress response (e.g., H2O2), and regulation of virulence factors and virulence-associated genes.}, } @article {pmid31786395, year = {2020}, author = {Xu, R and Zhang, S and Meng, F}, title = {Large-sized planktonic bioaggregates possess high biofilm formation potentials: Bacterial succession and assembly in the biofilm metacommunity.}, journal = {Water research}, volume = {170}, number = {}, pages = {115307}, doi = {10.1016/j.watres.2019.115307}, pmid = {31786395}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; Calcium Hydroxide ; *Extracellular Polymeric Substance Matrix ; Hydroxyapatites ; Phylogeny ; *Plankton ; Silicates ; }, abstract = {Wanted and unwanted surface-attached growth of bacteria is ubiquitous in natural and engineered settings. Normally, attachment of planktonic cells to media surfaces initiates biofilm formation and fundamentally regulates biofilm assembly processes. Here, culturing biofilm with planktonic sludge as source community, we found distinct succession profiles of biofilm communities sourced from the size-fractionated sludge flocs (<25; 25-120; >120 μm). Null model analyses revealed that deterministic process dominated in biofilm community assemblies but decreased with decreasing floc size. Additionally, the relative importance of environmental selection increased with increasing floc size of the source sludge, whereas homogenizing dispersal and ecological drift followed opposite trends. Phylogenetic molecular ecological networks (pMENs) indicated that species interactions were intensive in biofilm microbiota developed from large-sized flocs (>120 μm), as evidenced by the low modularity and harmonic geodesic distance and the high average degree. Intriguingly, the keystone taxa in these biofilm ecological networks were controlled by distinct interaction patterns but all showed strong habitat characteristics (e.g., facultative anaerobic, motile, hydrophobic and involved in extracellular polymeric substance metabolism), corroborating the crucial roles of environmental filtering in structuring biofilm community. Taken together, our findings highlight the role of planktonic floc properties in biofilm community assembly and advance our understanding of microbial ecology in biofilm-based systems.}, } @article {pmid31786294, year = {2020}, author = {Jou, IA and Caterino, M and Schnupf, U and Rizzo, R and Cescutti, P and Brady, JW}, title = {Ramachandran conformational energy maps for disaccharide linkages found in Burkholderia multivorans biofilm polysaccharides.}, journal = {International journal of biological macromolecules}, volume = {143}, number = {}, pages = {501-509}, pmid = {31786294}, issn = {1879-0003}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Burkholderia/*chemistry/physiology ; Carbohydrate Conformation ; Disaccharides/*chemistry ; Polysaccharides, Bacterial/*chemistry ; }, abstract = {Ramachandran conformational energy maps have been prepared for all of the glycosidic linkages found in the C1576 exopolysaccharide that constitutes the biofilms of the bacterial species Burkholderia multivorans, a member of the Burkholderia cepacian complex that was isolated from a cystic fibrosis patient. This polysaccharide is a rhamnomannan with a tetrasaccharide repeat unit containing two mannose residues and two rhamnose residues, -[3-α-d-Man-(1→2)-α-d-Man-(1→2)-α-d-Rha-(1→3)-α-d-Rha-(1→]n-, where approximately 50% of the rhamnoses are randomly methylated on their O3 hydroxyl groups, further increasing the overall hydrophobicity of the chains. Because of the methylation, the tetrasaccharide repeat unit actually contains six possible linkages. The conformational energy maps are fully adiabatic relaxed maps in which the energy for each (ϕ,ψ) grid point on the map represents the lowest possible energy for the molecule in that conformation, considering all the combinations of the other degrees of freedom, such as hydroxyl orientations. Molecular dynamics simulations were used to verify that these maps indeed describe the conformational dynamics of these linkages. All six linkages were found to be quite restricted in possible ϕ angles, but to exhibit several possible low-energy ψ angles, suggesting that these chains could be quite flexible.}, } @article {pmid31785460, year = {2020}, author = {Abdulgader, M and Yu, QJ and Zinatizadeh, AA and Williams, P and Rahimi, Z}, title = {Performance and kinetics analysis of an aerobic sequencing batch flexible fibre biofilm reactor for milk processing wastewater treatment.}, journal = {Journal of environmental management}, volume = {255}, number = {}, pages = {109793}, doi = {10.1016/j.jenvman.2019.109793}, pmid = {31785460}, issn = {1095-8630}, mesh = {Animals ; Biofilms ; Bioreactors ; Industrial Waste ; Kinetics ; Milk ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {In this study, a sequencing batch flexible fibre biofilm reactor (SB-FFBR) is used for efficient and cost-effective treatment of milk processing wastewater (MPW). The SB-FFBR, modified type of a typical sequencing batch reactor (SBR), is made up of eight bundles of flexible fibre as a supporting media for microorganisms'growth. The working volume and the cycle length of the bioreactor are 8 L and 24 h, respectively. The biological performance of the bioreactor is studied at 10, 3 and 10 various levels of the influent chemical oxygen demand (CODin; 610-8193 mg L[-1]), retention time (RT; 1, 1.6 and 2 days), and organic loading rate (OLR; 0.38-8.19 gCOD m[-3]d[-1]), respectively. From the results, the minimum COD and total suspended solids (TSS) removal efficiency of 86.8% and 77.3% were achieved at OLR of 8.2 kg COD m[-3]d[-1], CODin of 8193 mg L[-1] and RT of 1 day. While, an excellent COD and TSS removal efficiency were found to be 97.5% and 99.3%, respectively, at low OLR of 0.4 kg COD m[-3]d[-1], CODin of 945 mg L[-1] and RT of 2 days. Furthermore, the kinetic coefficients of COD removal were computed using a first order substrate removal model at different COD concentrations. The first order kinetic constant, (k), was 0.60, 0.65 and 0.357 h[-1] for 500, 810 and 2000 mg COD L[-1], respectively. The use of the flexible fibre as a packing material provided a huge surface area for more microorganism attachment. Therefore, the results demonstrated the SB-FFBR has acted as a suitable and effective strategy in treatment of milk processing industrial wastewater.}, } @article {pmid31784952, year = {2020}, author = {Lee, DH and Kim, BS and Kang, SS}, title = {Bacteriocin of Pediococcus acidilactici HW01 Inhibits Biofilm Formation and Virulence Factor Production by Pseudomonas aeruginosa.}, journal = {Probiotics and antimicrobial proteins}, volume = {12}, number = {1}, pages = {73-81}, pmid = {31784952}, issn = {1867-1314}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Bacteriocins/*pharmacology ; Biofilms/*drug effects ; Pediococcus acidilactici/*metabolism ; Pseudomonas aeruginosa/*drug effects ; Virulence Factors/*metabolism ; }, abstract = {Pseudomonas aeruginosa is a potential source of food contamination that leads to food spoilage and infections as a result of the generation of biofilm and virulence factors. In the present study, we demonstrate that bacteriocin produced by Pediococcus acidilactici HW01 (HW01 bacteriocin) effectively inhibited the biofilm formation of Ps. aeruginosa (66.41, 45.77, and 21.73% of biofilm formation at 0.5, 1, and 2 mg/mL of HW01 bacteriocin, respectively) as well as the production of virulence factors. By means of a microtiter plate method and scanning electron microscopy, HW01 bacteriocin inhibited biofilm formation by Ps. aeruginosa in a dose-dependent manner. Although the viability of biofilm cells of Ps. aeruginosa was reduced in the presence of HW01 bacteriocin, the viability of planktonic cells of Ps. aeruginosa was not affected by HW01 bacteriocin (2.0 × 10[9] CFU/mL vs. 2.4 × 10[9] CFU/mL in the absence and the presence of HW01 bacteriocin, respectively). Additionally, HW01 bacteriocin decreased the twitching motility of Ps. aeruginosa as well as the production of virulence factors, such as pyocyanin, protease, and rhamnolipid. Furthermore, HW01 bacteriocin significantly inhibited Ps. aeruginosa biofilm formation on the surface of stainless steel (57% reduction at 24 h and 83% reduction at 72 h). These results indicate that HW01 bacteriocin is an effective antagonist of Ps. aeruginosa as a result of its ability to inhibit biofilm formation and the production of virulence factors.}, } @article {pmid31784806, year = {2020}, author = {Fernandes, AWC and Dos Anjos Santos, VL and Araújo, CRM and de Oliveira, HP and da Costa, MM}, title = {Anti-biofilm Effect of β-Lapachone and Lapachol Oxime Against Isolates of Staphylococcus aureus.}, journal = {Current microbiology}, volume = {77}, number = {2}, pages = {204-209}, pmid = {31784806}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Blood Culture ; Microbial Sensitivity Tests ; Naphthoquinones/*pharmacology ; Oximes/*pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {Antimicrobial resistance in bacteria, such as Staphylococcus aureus, has been the subject of many assistance studies of alternatives for the treatment of infections. These studies aim to solve this problem for bacteria, such as biofilm formation. Aiming to control the emergence of the problem or enhance antibiotic activity, the data sources are inserted into new therapeutic alternatives for the treatment of infections. β-Lapachone and Lapachol Oxime are semi-synthetic derivatives of Lapachol with antimicrobial potential. Clinical isolates from human blood cultures were used in this study. Scanning electron microscopy (SEM) was performed following the glutaraldehyde fixation protocol. The presence of β-Lapachone and Lapachol Oxima interfered in the biofilm formation state. In the MEV, the effect was observed in the reduction of the population of biofilm-forming cells. Therefore, it was possible to conclude the promising potential of the anti-biofilm of substances, justifying the nature of the natural products as agents of inspiration for the detection of new compounds with the biological function.}, } @article {pmid31784584, year = {2019}, author = {Berditsch, M and Afonin, S and Reuster, J and Lux, H and Schkolin, K and Babii, O and Radchenko, DS and Abdullah, I and William, N and Middel, V and Strähle, U and Nelson, A and Valko, K and Ulrich, AS}, title = {Supreme activity of gramicidin S against resistant, persistent and biofilm cells of staphylococci and enterococci.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {17938}, pmid = {31784584}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Enterococcus faecalis/*drug effects/physiology ; Enterococcus faecium/*drug effects/physiology ; Gram-Positive Bacterial Infections/drug therapy/microbiology ; Gramicidin/*pharmacology ; Humans ; Models, Molecular ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; Zebrafish ; }, abstract = {Three promising antibacterial peptides were studied with regard to their ability to inhibit the growth and kill the cells of clinical strains of Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium. The multifunctional gramicidin S (GS) was the most potent, compared to the membranotropic temporin L (TL), being more effective than the innate-defence regulator IDR-1018 (IDR). These activities, compared across 16 strains as minimal bactericidal and minimal inhibitory concentrations (MIC), are independent of bacterial resistance pattern, phenotype variations and/or biofilm-forming potency. For S. aureus strains, complete killing is accomplished by all peptides at 5 × MIC. For E. faecalis strains, only GS exhibits a rapid bactericidal effect at 5 × MIC, while TL and IDR require higher concentrations. The biofilm-preventing activities of all peptides against the six strains with the largest biofilm biomass were compared. GS demonstrates the lowest minimal biofilm inhibiting concentrations, whereas TL and IDR are consistently less effective. In mature biofilms, only GS completely kills the cells of all studied strains. We compare the physicochemical properties, membranolytic activities, model pharmacokinetics and eukaryotic toxicities of the peptides and explain the bactericidal, antipersister and antibiofilm activities of GS by its elevated stability, pronounced cell-penetration ability and effective utilization of multiple modes of antibacterial action.}, } @article {pmid31784252, year = {2020}, author = {Zhang, J and Miao, Y and Zhang, Q and Sun, Y and Wu, L and Peng, Y}, title = {Mechanism of stable sewage nitrogen removal in a partial nitrification-anammox biofilm system at low temperatures: Microbial community and EPS analysis.}, journal = {Bioresource technology}, volume = {297}, number = {}, pages = {122459}, doi = {10.1016/j.biortech.2019.122459}, pmid = {31784252}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; Extracellular Polymeric Substance Matrix ; *Microbiota ; *Nitrification ; Nitrogen ; Oxidation-Reduction ; Sewage ; Temperature ; }, abstract = {Stable sewage nitrogen removal with nitrogen removal efficiency of 87.5 ± 2.2% was achieved in a partial nitrification-anammox (PNA) biofilm system at low temperatures (12.8-16.3 °C). High-throughput sequencing analysis indicated that the microbial community structure in the sequencing batch biofilm reactor (SBBR) remained reasonably stable. Candidatus Brocadia was the only detected anammox genus and remained stable at 0.3-0.5%. Some psychrotolerant microorganisms that could secrete cryoprotective extracellular polymeric substances (EPS), including Flavobacterium and Thermomonas, were enriched at low temperatures. This could be conducive to the stable operation of the PNA-SBBR. Moreover, according to the EPS composition and characteristics analysis, the secretion of tightly-bound EPS that bound to the cell surface containing plentiful protein was stimulated at low temperatures, further improving the system stability. Overall, the reasonably stable microbial community structure, enrichment of psychrotolerant microorganisms, and increased secretion of EPS could play important roles for stable sewage nitrogen removal at low temperatures.}, } @article {pmid31783455, year = {2020}, author = {Xu, J and Pang, H and He, J and Nan, J and Wang, M and Li, L}, title = {Start-up of aerobic granular biofilm at low temperature: Performance and microbial community dynamics.}, journal = {The Science of the total environment}, volume = {698}, number = {}, pages = {134311}, doi = {10.1016/j.scitotenv.2019.134311}, pmid = {31783455}, issn = {1879-1026}, mesh = {Ammonium Compounds ; *Biofilms ; Bioreactors/microbiology ; Microbiota ; Nitrogen ; Phosphorus ; *Temperature ; Waste Disposal, Fluid/*methods ; }, abstract = {Low temperature is a great challenge for the biological treatment of wastewater. In this study, the rapid start-up of aerobic granular biofilm (AGF) reactor was realized by adding micro-sized polyurethane (PU) sponges as matrices at 10 °C. The results showed that the granulation process of AGF was different from that of traditional aerobic granular sludge and biofilms, which was formed by using the sludge intercepted in PU matrix instead of sponge skeletons as granulation carriers. During the 5-month operation period, stable pollutants removal performance was achieved within 70 days, besides, the corresponding ammonium, total nitrogen, and total phosphorus removal efficiencies were 98%, 70%, and 95%, respectively. The addition of PU matrices inhibited the growth of filamentous bacteria and provided support for high structural stability of AGF. With the operation of the reactor, the relative abundance of traditional denitrifying bacteria (genera Thauera and Acidovorax, etc.) decreased gradually, and the putative denitrifying phosphorus accumulating genus, Dechloromonas, occupied a dominant position in the system. This experiment showed that AGF system could be successfully started-up and operated with efficient pollutants removal performance under low temperature when using micro-sized PU sponges as matrices.}, } @article {pmid31783343, year = {2020}, author = {Dygico, LK and Gahan, CGM and Grogan, H and Burgess, CM}, title = {The ability of Listeria monocytogenes to form biofilm on surfaces relevant to the mushroom production environment.}, journal = {International journal of food microbiology}, volume = {317}, number = {}, pages = {108385}, doi = {10.1016/j.ijfoodmicro.2019.108385}, pmid = {31783343}, issn = {1879-3460}, mesh = {Agaricales/*physiology ; Aluminum ; Biofilms/*growth & development ; Disinfection/methods ; Food Contamination/*prevention & control ; Food Microbiology ; Ireland ; Listeria monocytogenes/*growth & development ; Polycarboxylate Cement ; Polystyrenes ; Rubber ; Stainless Steel ; Temperature ; }, abstract = {Due to its ubiquitous nature, Listeria monocytogenes is a threat to all fresh fruits and vegetables, including mushrooms, which are Ireland's largest horticultural crop. Although fresh cultivated mushrooms (Agaricus bisporus) have not been previously linked with listeriosis outbreaks, the pathogen still poses a threat to the industry, particularly due to its ability to form biofilms. This threat is highlighted by the multiple recalls of mushroom products caused by L. monocytogenes contamination and by previous studies demonstrating that L. monocytogenes is present in the mushroom production environment. In this study, the biofilm formation potential of L. monocytogenes strains isolated from the mushroom production environment was investigated on materials and at temperatures relevant to mushroom production. A preliminary assessment of biofilm formation of 73 mushroom industry isolates was undertaken using a crystal violet assay on polystyrene microtitre plates. The biofilm formation of a subset (n = 7) of these strains was then assessed on twelve different materials, including materials that are representative of the materials commonly found in the mushroom production environments, using the CDC biofilm reactor. Vertical scanning interferometry was used to determine the surface roughness of the chosen materials. All the strains tested using the CDC biofilm reactor were able to form biofilms on the different surfaces tested but material type was found to be a key determining factor on the levels of biofilm formed. Stainless steel, aluminium, rubber, polypropylene and polycarbonate were all able to support biofilm levels in the range of 4-4.9 log10 CFU/cm[2], for seven different L. monocytogenes strains. Mushroom industry-specific materials, including growing nets and tarpaulins, were found to support biofilms levels between 4.7 and 6.7 log10 CFU/cm[2]. Concrete was found to be of concern as it supported 7.7 log10 CFU/cm[2] of biofilm for the same strains; however, sealing the concrete resulted in an approximately 2-log reduction in biofilm levels. The surface roughness of the materials varied greatly between the materials (0.7-3.5 log10 Ra) and was found to have a positive correlation with biofilm formation (rs = 0.573) although marginally significant (P = 0.051). The results of this study indicate that L. monocytogenes can readily form biofilms on mushroom industry relevant surfaces, and additionally identifies surfaces of specific concern, where rigorous cleaning and disinfection is required.}, } @article {pmid31780773, year = {2019}, author = {Siddik, A and Satheesh, S}, title = {Characterization and assessment of barnacle larval settlement-inducing activity of extracellular polymeric substances isolated from marine biofilm bacteria.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {17849}, pmid = {31780773}, issn = {2045-2322}, mesh = {Animals ; Bivalvia/growth & development/*microbiology ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; *Host-Pathogen Interactions ; Larva/microbiology/physiology ; *Movement ; Oligosaccharides/analysis ; Pseudoalteromonas/metabolism/pathogenicity ; Vibrio/metabolism/pathogenicity ; }, abstract = {Extracellular polymeric substances (EPSs) are the hydrated gelatinous matrix produced by microorganisms for attachment in a biofilm environment. In this study, the compositional variation between EPSs of three marine biofilm bacteria (Pseudoalteromonas shioyasakiensis, Vibrio harveyi and Planomicrobium sp.) were analysed by GC-MS, [1]H NMR, FT-IR and XRD and SEM. The ecological significance of exopolymers was assessed in vivo using marine model organism barnacle larvae for their settlement-inducing activity. Chemical analysis revealed the presence of glycan fucosylated oligosaccharides, tetraose, trisaccharides, iso-B-Pentasaccharides, sialyllactose, oligomannose, galacto-N-biose, difucosyl-para-lacto-N-neohexaose, 3'-sialyl N-acetyllactosamine and isoglobotriaose-β-N(Acetyl)-Propargyl in all extracted EPSs. Bioassay results indicated that treatment of the barnacle larvae with EPSs from three bacterial strains enhanced settlement on substrates. In conclusion, this study highlighted the role of water-soluble EPSs in the invertebrate larval settlement on artificial materials.}, } @article {pmid31780206, year = {2020}, author = {Li, Q and Gu, P and Ji, X and Li, H and Zhang, J and Zheng, Z}, title = {Response of submerged macrophytes and periphyton biofilm to water flow in eutrophic environment: Plant structural, physicochemical and microbial properties.}, journal = {Ecotoxicology and environmental safety}, volume = {189}, number = {}, pages = {109990}, doi = {10.1016/j.ecoenv.2019.109990}, pmid = {31780206}, issn = {1090-2414}, mesh = {Antioxidants/metabolism ; Biofilms ; Hydrocharitaceae/metabolism/*physiology ; Malondialdehyde/analysis/metabolism ; *Microbiota ; Periphyton/*physiology ; Photosynthesis ; Plant Leaves/metabolism ; RNA, Ribosomal, 16S/metabolism ; Water/chemistry ; Water Movements ; }, abstract = {The integrated effects of water flow on submerged macrophytes (Vallisneria natans) and leaf biofilms were comprehensively investigated in eutrophic microcosm. Changes in aquatic environmental factors were analyzed and water flow was found to elevate eutrophic water quality, especially in terms of TP removal. The removal efficiency of TP reached 78.95% in flowing water, which was more than 10-fold higher than in static water. Water flow altered the morphological and physiological characteristics of plants, decreasing the cell wall thickness and rate of photosynthesis, while promoting the accumulation of soluble sugar and protein in leaves. The starch content also increased with water flow, and significantly larger starch granules were observed in chloroplast. Furthermore, oxidative damage was evidenced by the consistently higher content of malondialdehyde in flowing water. Superoxide dismutase (SOD), peroxidase (POD) and Catalase (CAT) were induced in plants exposed to water flow, as an antioxidant stress response. The results of 16S rRNA high-throughput sequencing analysis showed that the structure of the biofilm microbial community changed in response to water flow. These results expand our understanding of the effects of water flow on submerged macrophytes and periphyton biofilms in eutrophic environments.}, } @article {pmid31779615, year = {2019}, author = {Batista, IR and Prates, ACL and Santos, BS and Araújo, JCC and Bonfim, YCO and Pimenta Rodrigues, MV and Morceli, G and Polettini, J and Cavalleri, AC and Winkelstroter, LK and Pereira, VC}, title = {Determination of antimicrobial susceptibility and biofilm production in Staphylococcus aureus isolated from white coats of health university students.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {18}, number = {1}, pages = {37}, pmid = {31779615}, issn = {1476-0711}, support = {2016/12252-2//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2016/15809-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, mesh = {Anti-Bacterial Agents ; Bacterial Proteins/genetics ; Biofilms/growth & development ; Containment of Biohazards ; Genes, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*isolation & purification ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins/genetics ; Protective Clothing/*microbiology ; Staphylococcus aureus/drug effects/genetics/*isolation & purification ; Students ; Universities ; }, abstract = {This study aimed at detecting Staphylococcus aureus from white coats of college students and characterizing antimicrobial susceptibility and biofilm production. Bacterial samples (n = 300) were obtained from white coats of 100 college students from August 2015 to March 2017 S. aureus was isolated and it´s resistance profile was assessed by antimicrobial disk-diffusion technique, screening for methicillin-resistant Staphylococcus aureus (MRSA), detection of mecA gene by PCR, and determination of staphylococcal cassette chromosome mec (SCCmec) by multiplex PCR. Congo red agar (CRA) and icaA and icaD genes by PCR were used for biofilm characterization. S. aureus was identified in 45.0% of samples. Resistance of S. aureus sample to antimicrobial was seen for penicillin (72.59%), erythromycin (51.85%), cefoxitin (20.74%), oxacillin (17.04%), clindamycin (14.81%) and levofloxacin (5.18%). MRSA was detected in 53.3% of the samples with SCCmec I (52.8%), SCCmec III (25%) and SCCmec IV (11.1%). Biofilm production was observed in 94.0% S. aureus samples. These data show that biosafety measures need to be enhanced in order to prevent dissemination of multiresistant and highly adhesive bacteria across other university settings, relatives, and close persons.}, } @article {pmid31779259, year = {2019}, author = {Yaita, K and Gotoh, K and Nakano, R and Iwahashi, J and Sakai, Y and Horita, R and Yano, H and Watanabe, H}, title = {Biofilm-Forming by Carbapenem Resistant Enterobacteriaceae May Contribute to the Blood Stream Infection.}, journal = {International journal of molecular sciences}, volume = {20}, number = {23}, pages = {}, pmid = {31779259}, issn = {1422-0067}, mesh = {Adult ; Aged ; Aged, 80 and over ; Bacteremia/*microbiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Carbapenem-Resistant Enterobacteriaceae/classification/isolation & purification/*physiology ; Catheters, Indwelling/microbiology ; Drug Resistance, Multiple, Bacterial ; Enterobacteriaceae Infections/*microbiology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Young Adult ; }, abstract = {Bloodstream infection (BSI) due to carbapenem-resistant Enterobacteriaceae (CRE) has a high mortality rate and is a serious threat worldwide. Ten CRE strains (eight Enterobacter cloacae, one Klebsiella pneumoniae and one Citrobacter freundii) were isolated from the blood of nine patients, a percentage of whom had been treated with indwelling devices. The steps taken to establish cause included minimum inhibitory concentration (MIC) tests, a pulsed-field gel electrophoresis (PFGE), biofilm study, a multiplex PCR for resistant genes of carbapenemases and extended-spectrum beta-lactamases (ESBLs), and plasmid incompatibility typing. All strains showed a tendency toward resistance to multiple antibiotics, including carbapenems. Frequently isolated genes of ESBLs and carbapenemases include blaTEM-1 (four strains), blaSHV-12 (four strains) and blaIMP-1 (six strains). A molecular analysis by PFGE was used to divide the XbaI-digested genomic DNAs of 10 CRE strains into eight patterns, and the analysis showed that three E. cloacae strains detected from two patients were either identical or closely related. The biofilm production of all CRE strains was examined using a microtiter biofilm assay, and biofilm growth in continuous flow chambers was observed via the use of a confocal laser scanning microscope. Our study indicates that biofilm formation on indwelling devices may pose a risk of BSI due to CRE.}, } @article {pmid31779134, year = {2019}, author = {Varghese, J and Ramenzoni, LL and Shenoy, P and Nayak, UY and Nayak, N and Attin, T and Schmidlin, PR}, title = {In Vitro Evaluation of Substantivity, Staining Potential, and Biofilm Reduction of Guava Leaf Extract Mouth Rinse in Combination with its Anti-Inflammatory Effect on Human Gingival Epithelial Keratinocytes.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {23}, pages = {}, pmid = {31779134}, issn = {1996-1944}, abstract = {This study aimed to assess the biofilm reduction, staining potential, and cytotoxicity of guava extract mouth rinse compared to chlorhexidine (CHX). Substantivity, staining, and antibiofilm potential were investigated by spectrophotometry, colony-forming units, and luminosity color meter, respectively. The cell viability assay was conducted using a colorimetric assay to determine nontoxic levels of guava (0.15%) and CHX in human gingival epithelial keratinocytes (HGEK-16). Cells were treated with lipopolysaccharides (LPS, 1μg/mL) and guava to assess inflammatory gene expression levels of interleukin-β1, tumor necrosis factor-α, and Prostaglandin E2. A scratch wound healing assay investigated the effects of guava on cell migration. The teeth coated in guava mouth rinse displayed 19.4% higher substantivity compared to CHX (0.2%), and the anti-biofilm reduction was observed with both guava and CHX mouth rinses (P < 0.05). The overall discoloration changes were higher with CHX and distilled water compared to guava. Also, guava significantly enhanced HGEK-16 cell viability (P < 0.05), and IL-β1, TNFα and PGE2 expression presented a 0.6-fold decrease when exposed to guava and LPS (P < 0.05). The present study showed that guava mouth rinse fulfilled the requirement for an effective and useful oral care product with desirable substantivity and anti-biofilm action. In addition, guava reduced the inflammation response in HGEK-16 and may be a potential oral rinse for oral anti-inflammatory therapies.}, } @article {pmid31778756, year = {2020}, author = {Martínez, M and Polizzotto, A and Flores, N and Semorile, L and Maffía, PC}, title = {Antibacterial, anti-biofilm and in vivo activities of the antimicrobial peptides P5 and P6.2.}, journal = {Microbial pathogenesis}, volume = {139}, number = {}, pages = {103886}, doi = {10.1016/j.micpath.2019.103886}, pmid = {31778756}, issn = {1096-1208}, mesh = {Amino Acids/chemistry ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Biofilms/*drug effects ; Chemical Phenomena ; Dose-Response Relationship, Drug ; Female ; Mice ; Microbial Sensitivity Tests ; Pneumonia, Bacterial/metabolism/microbiology ; Pseudomonas aeruginosa/drug effects/ultrastructure ; Staphylococcus aureus/drug effects/ultrastructure ; }, abstract = {Cationic antimicrobial peptides (AMPs) are short linear amino acid sequences, which display antimicrobial activity against a wide range of bacterial species. They are promising novel antimicrobials since they have shown bactericidal effects against multiresistant bacteria. Their amphiphilic structure with hydrophobic and cationic regions drives their interaction with anionic bacterial cytoplasmic membranes, which leads to their disruption. In this work two synthetic designed AMPs, P5 and P6.2, which have been previously analyzed in their ability to interact with bacterial or eukaryotic membranes, were evaluated in their anti-biofilm and in vivo antibacterial activity. In a first step, a time-kill kinetic assay against P. aeruginosa and S. aureus and a curve for hemolytic activity were performed in order to determine the killing rate and the possible undesirable toxic effect, respectively, for both peptides. The biofilm inhibitory activity was quantified at sub MIC concentrations of the peptides and the results showed that P5 displayed antibiofilm activity on both strains while P6.2 only on S. aureus. Scanning electron microscopy (SEM) of bacteria treated with peptides at their MIC revealed protruding blisters on Gam-negative P. aeruginosa strain, but almost no visible surface alteration on Gram-positive S. aureus. These micrographs highlighted different manifestations of the membrane-disrupting activity that these kinds of peptides possess. Finally, both peptides were analyzed in vivo, in the lungs of neutropenic mice previously instilled with P. aeruginosa. Mice lungs were surgically extracted and bacteria and pro-inflammatory cytokines (IL-β, IL-6 and TNF-α) were quantified by colony forming units and ELISA, respectively. Results showed that instillation of the peptides produced a significant decrease in the number of living bacteria in the lungs, concomitant with a decrease in pro-inflammatory cytokines. Overall, the results presented here suggest that these two new peptides could be good candidates for future drug development for anti-biofilm and anti-infective therapy.}, } @article {pmid31778647, year = {2020}, author = {Baron, G and Altomare, A and Regazzoni, L and Fumagalli, L and Artasensi, A and Borghi, E and Ottaviano, E and Del Bo, C and Riso, P and Allegrini, P and Petrangolini, G and Morazzoni, P and Riva, A and Arnoldi, L and Carini, M and Aldini, G}, title = {Profiling Vaccinium macrocarpon components and metabolites in human urine and the urine ex-vivo effect on Candida albicans adhesion and biofilm-formation.}, journal = {Biochemical pharmacology}, volume = {173}, number = {}, pages = {113726}, doi = {10.1016/j.bcp.2019.113726}, pmid = {31778647}, issn = {1873-2968}, mesh = {Adult ; Anthocyanins/urine ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Chromatography, High Pressure Liquid/methods ; Female ; Flavonoids/urine ; Humans ; Hydroxybenzoates/urine ; Lactones/chemistry/*pharmacology/urine ; Mass Spectrometry/methods ; Pentanoic Acids/chemistry/*pharmacology/urine ; Plant Extracts/administration & dosage/metabolism/*urine ; Polyphenols/classification/urine ; Vaccinium macrocarpon/*chemistry ; Young Adult ; }, abstract = {The aim of this work was to profile, by using an HPLC-MS/MS method, cranberry compounds and metabolites found in human urine after ingestion of a highly standardized cranberry extract (Anthocran®). Two different strategies were adopted for the data analysis: a targeted and an untargeted approach. These strategies allowed the identification of 42 analytes including cranberry components, known metabolites and metabolites hitherto unreported in the literature, including six valerolactones/valeric acid derivatives whose presence in urine after cranberry consumption has never been described before. Absolute concentrations of 26 over 42 metabolites were obtained by using pure available standards. Urine collected at different time points after the last dosage of Anthocran® were tested on the reference strain C. albicans SC5314, a biofilm-forming strain. Fractions collected after 12 h were found to significantly reduce the adhesion and biofilm formation compared to the control (p < 0.05). A similar effect was then obtained by using Anthocran™ Phytosome™, the lecithin formulation containing 1/3 of standardized cranberry extract and formulated to enhance the absorption of the cranberry components. The urinary profile of cranberry components and metabolites in the urine fractions collected at 1 h, 6 h and 12 h after the last capsule intake were then reproduced by using the pure standards at the concentration ranges found in the urine fraction, and tested on C. albicans. Only the mixture mimicking the urinary fraction collected at 12 h and containing as main components, quercetin and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone was found effective thus confirming the ex-vivo results.}, } @article {pmid31778202, year = {2020}, author = {Salisbury, AM and Chen, R and Mullin, M and Foulkes, L and Percival, SL}, title = {The Effects of a Concentrated Surfactant Gel on Biofilm EPS.}, journal = {Surgical technology international}, volume = {36}, number = {}, pages = {31-35}, pmid = {31778202}, issn = {1090-3941}, mesh = {DNA, Bacterial ; *Extracellular Polymeric Substance Matrix ; Pseudomonas aeruginosa ; Surface-Active Agents ; }, abstract = {INTRODUCTION: The aim of this study was to evaluate if a poloxamer-based concentrated surfactant gel (CSG), containing antibacterial preservative agents, had the ability to reduce the levels of biofilm extracellular polymeric substances (EPS), specifically proteins and extracellular DNA (eDNA), as these are found to be the most immunogenic, within an in vitro biofilm.

MATERIALS AND METHODS: A 24-hour biofilm of P. aeruginosa ATCC 15442 was grown in a 12-well plate and treated for 24 hours with a CSG coated onto Multisorb® (BSN Medical Limited, Hull, United Kingdom). EPS were extracted from each sample using 1M sodium chloride. Protein and DNA in EPS extractions was determined quantitatively using the Pierce™ Coomassie (Bradford) protein assay kit and a microplate SYTO 9™ (ThermoFisher Scientific, Paisley, United Kingdom) fluorescent assay, respectively. Protein and DNA was also determined qualitatively using confocal laser scanning microscopy (CLSM).

RESULTS: Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 7.38mg/mL protein was isolated from the extracted EPS in the untreated control. In comparison, the protein concentration found in the extracted EPS from biofilms treated with a CSG was 6.39mg/mL, showing a 13.4% reduction. Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 11.71mg/mL eDNA was isolated from the extracted EPS in the untreated control. In comparison, the eDNA concentration found in the extracted EPS from biofilms treated with a CSG was 0.65mg/mL, showing a 94.5% reduction. Following statistical analysis of the data, the decrease in protein isolated following CSG treatment was within error; however, the decrease in eDNA isolated was statistically significant, showing the ability of the CSG to break up biofilm EPS in vitro. Using confocal laser microscopy and staining techniques, a large quantity of protein and eDNA could be observed in samples from the untreated control. In comparison, a reduction in EPS protein and eDNA was observed in samples that had been treated with a CSG.

CONCLUSION: The data presented here potentially shows the ability of a CSG to reduce components of the P. aeruginosa biofilm EPS. The reduction in eDNA following CSG treatment may contribute to the dispersal of the biofilm, potentially increasing the susceptibility of it to antimicrobials, and should be explored further.}, } @article {pmid31778072, year = {2019}, author = {Maheshwari, M and Abul Qais, F and Althubiani, AS and Abulreesh, HH and Ahmad, I}, title = {Bioactive extracts of Carum copticum and thymol inhibit biofilm development by multidrug-resistant extended spectrum β-lactamase producing enteric bacteria.}, journal = {Biofouling}, volume = {35}, number = {9}, pages = {1026-1039}, doi = {10.1080/08927014.2019.1688305}, pmid = {31778072}, issn = {1029-2454}, mesh = {Biofilms/*drug effects ; Carum/*chemistry ; Drug Resistance, Multiple, Bacterial/*drug effects ; Gas Chromatography-Mass Spectrometry ; Gastrointestinal Microbiome/*drug effects ; Humans ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Thymol/*pharmacology ; beta-Lactamase Inhibitors/*pharmacology ; }, abstract = {The emergence and spread of multidrug-resistant (MDR) pathogenic bacteria is a clinical problem that requires novel anti-infective agents. Targeting pathogenic biofilms is considered a promising strategy to control bacterial infections. In this study, bioactive extracts of Carum copticum were investigated for their anti-biofilm efficacy against extended spectrum β-lactamase (ESβL) producing MDR enteric bacteria. Thymol was also tested for its anti-biofilm properties, as gas chromatography-mass spectrometry revealed a high content (65.8%) of this phytochemical in the C. copticum methanolic extract. Biofilm inhibition was assessed in microtitre plates and further validated by light, electron and confocal laser microscopy. Sub-inhibitory concentrations of bioactive extracts of C. copticum and thymol significantly prevented biofilm development, ranging from 78.6 to 83.9% reductions. Microscopic analysis revealed that biofilms made by ESβL producing MDR enteric bacteria had a weakened structure, scattered microcolonies, and reduced cell density and thickness after exposure to the bioactive extracts and thymol.}, } @article {pmid31778071, year = {2019}, author = {Afonso, TB and Simões, LC and Lima, N}, title = {In vitro assessment of inter-kingdom biofilm formation by bacteria and filamentous fungi isolated from a drinking water distribution system.}, journal = {Biofouling}, volume = {35}, number = {10}, pages = {1041-1054}, doi = {10.1080/08927014.2019.1688793}, pmid = {31778071}, issn = {1029-2454}, mesh = {Bacteria/*isolation & purification/metabolism ; Biofilms/*growth & development ; Drinking Water/*microbiology ; Fungi/*isolation & purification/metabolism ; Water Supply/*standards ; }, abstract = {The main focus so far in the study of biofilm formation in drinking water has been bacteria. Studies on biofilm formation involving filamentous fungi are, therefore, scarce. This study aimed to assess and characterize the ability of these microorganisms to interact with bacteria whilst forming inter-kingdom biofilms. Biofilms were analysed in terms of total biomass, metabolic activity, bacterial colony forming units and morphology by epifluorescence microscopy. The quantitative methods revealed that biofilm mass increased over time for both single and inter-kingdom biofilms, while specific metabolic activity decreased, in general, along the time points evaluated. Microscopic data visually confirmed the biofilm mass increase over time. This study shows that fungal stage development is important in the first 24 h of biofilm formation. Inter-kingdom biofilm formation is microorganism dependent and inter-kingdom biofilms may provide an advantage to the opportunistic bacterium Acinetobacter calcoaceticus to replicate and proliferate when compared with Methylobacterium oryzae.}, } @article {pmid31776432, year = {2019}, author = {Sindi, A and Chawn, MVB and Hernandez, ME and Green, K and Islam, MK and Locher, C and Hammer, K}, title = {Anti-biofilm effects and characterisation of the hydrogen peroxide activity of a range of Western Australian honeys compared to Manuka and multifloral honeys.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {17666}, pmid = {31776432}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/ultrastructure ; Bacterial Outer Membrane/drug effects ; Biofilms/*drug effects ; *Honey ; Hydrogen Peroxide/*pharmacology ; Microbial Sensitivity Tests ; Pigments, Biological/biosynthesis ; Western Australia ; }, abstract = {The antibacterial activity of honeys derived from the endemic flora of the southwest corner of Western Australia, including the trees Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla), remains largely unexplored. Investigation of these honeys showed minimum inhibitory concentrations (MICs) of 6.7-28.0% (w/v) against Gram positive and negative bacteria. Honey solutions showed enhanced antibacterial activity after hydrogen peroxide was allowed to accumulate prior to testing, with a mean MIC after accumulation of 14.3% compared to 17.4% before accumulation. Antibacterial activity was reduced after treatment with catalase enzyme, with a mean MIC of 29.4% with catalase compared to 15.2% without catalase. Tests investigating the role of the Gram negative outer membrane in honey susceptibility revealed increases in activity after destabilisation of the outer membrane. Honeys reduced both the formation of biofilm and the production of bacterial pigments, which are both regulated by quorum sensing. However, these reductions were closely correlated with global growth inhibition. Honey applied to existing biofilms resulted in decreased metabolic activity and minor decreases in viability. These results enhance our understanding of the mechanisms of antibacterial action of Jarrah and Marri honeys, and provide further support for the use of honey in the treatment of infected wounds.}, } @article {pmid31775200, year = {2019}, author = {Wu, Y and Li, J and Qiao, M and Meng, D and Meng, Q and Qiao, J and Zhang, X and Wang, L and Cai, K and Zhang, J and Zhang, Z and Yu, W and Cai, X}, title = {Characteristic profiles of biofilm, enterotoxins and virulence of Staphylococcus aureus isolates from dairy cows in Xinjiang Province, China.}, journal = {Journal of veterinary science}, volume = {20}, number = {6}, pages = {e74}, pmid = {31775200}, issn = {1976-555X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Cattle ; Cattle Diseases/*microbiology ; China ; Dairying ; Drug Resistance, Bacterial/*genetics ; Enterotoxins/*chemistry ; Female ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/drug effects/genetics/*pathogenicity/*physiology ; Virulence ; }, abstract = {As an important zoonotic pathogen, Staphylococcus aureus has led to serious mastitis and endometritis in infected dairy cows. In this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine drug susceptibility and biofilm (BF) formation ability. Enterotoxin-related genes were detected, and the transcription levels of genes related to BF formation were determined by using reverse transcription-quantitative polymerase chain reaction. Moreover, the pathogenicity of isolates with different BF formation abilities was determined by measuring their hemolysis activity, half lethal dose (LD50) and organ bacterial load. The results showed that 86.0% of S. aureus isolates could form BF. Among them, 42.1% of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3% of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than those of conventional enterotoxin genes. Furthermore, isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than those of the isolates with weak or no BF ability. However, isolates without BF ability produced more severe pathological changes than those of isolates with strong BF formation ability. These findings suggest that higher BF ability and presence of novel enterotoxin genes are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolates may pose potential threats to food safety.}, } @article {pmid31774855, year = {2019}, author = {Senpuku, H and Tuna, EB and Nagasawa, R and Nakao, R and Ohnishi, M}, title = {The inhibitory effects of polypyrrole on the biofilm formation of Streptococcus mutans.}, journal = {PloS one}, volume = {14}, number = {11}, pages = {e0225584}, pmid = {31774855}, issn = {1932-6203}, mesh = {Adult ; Biofilms/drug effects/*growth & development ; Humans ; Polymers/*pharmacology ; Pyrroles/*pharmacology ; Saliva/*microbiology ; Streptococcus mutans/drug effects/*growth & development/isolation & purification ; Young Adult ; }, abstract = {Streptococcus mutans primary thrives on the biofilm formation on the tooth surface in sticky biofilms and under certain conditions can lead to carious lesions on the tooth surface. To search for a new preventive material for oral biofilm-associated diseases, including dental caries, we investigated the effects of polypyrrole, which contains an electrochemical polymer and causes protonation and incorporation of anion under low pH condition, on the biofilm formation of S. mutans and other streptococci. In this study, polypyrrole was applied in biofilm formation assays with the S. mutans strains UA159 and its gtfB and gtfC double mutant (gtfBC mutant), S. sanguinis, S. mitis and S. gordonii on human saliva and bovine serum albumin-coated 96-well microtiter plates in tryptic soy broth supplemented with 0.25% sucrose. The effects of polypyrrole on biofilm formation were quantitatively and qualitatively observed. High concentrations of polypyrrole significantly inhibited the biofilm formation of S. mutans UA159 and S. sanguinis. As an inhibition mechanism, polypyrrole attached to the surface of bacterial cells, increased chains and aggregates, and incorporated proteins involving GTF-I and GTF-SI produced by S. mutans. In contrast, the biofilm formation of gtfBC mutant, S. sanguinis, S. mitis and S. gordonii was temporarily induced by the addition of low polypyrrole concentrations on human saliva-coated plate but not on the uncoated and bovine serum albumin-coated plates. Moreover, biofilm formation depended on live cells and, likewise, specific interaction between cells and binding components in saliva. However, these biofilms were easily removed by increased frequency of water washing. In this regard, the physical and electrochemical properties in polypyrrole worked effectively in the removal of streptococci biofilms. Polypyrrole may have the potential to alter the development of biofilms associated with dental diseases.}, } @article {pmid31773197, year = {2020}, author = {Chakraborty, P and Dastidar, DG and Paul, P and Dutta, S and Basu, D and Sharma, SR and Basu, S and Sarker, RK and Sen, A and Sarkar, A and Tribedi, P}, title = {Inhibition of biofilm formation of Pseudomonas aeruginosa by caffeine: a potential approach for sustainable management of biofilm.}, journal = {Archives of microbiology}, volume = {202}, number = {3}, pages = {623-635}, doi = {10.1007/s00203-019-01775-0}, pmid = {31773197}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Caffeine/*pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pseudomonas aeruginosa/drug effects/genetics/*physiology ; Quorum Sensing/drug effects ; Virulence Factors/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa is a potent biofilm forming organism causing several diseases on host involving biofilm. Several natural and synthetic molecules have been explored towards inhibiting the biofilm formation of Pseudomonas aeruginosa. In the current report, the role of a natural molecule namely caffeine was examined against the biofilm forming ability of P. aeruginosa. We have observed that caffeine shows substantial antimicrobial activity against P. aeruginosa wherein the minimum inhibitory concentration (MIC) of caffeine was found to be 200 μg/mL. The antibiofilm activity of caffeine was determined by performing a series of experiments using its sub-MIC concentrations (40 and 80 μg/mL). The results revealed that caffeine can significantly inhibit the biofilm development of P. aeruginosa. Caffeine has been found to interfere with the quorum sensing of P. aeruginosa by targeting the swarming motility. Molecular docking analysis further indicated that caffeine can interact with the quorum sensing proteins namely LasR and LasI. Thus, the result indicated that caffeine could inhibit the formation of biofilm by interfering with the quorum sensing of the organism. Apart from biofilm inhibition, caffeine has also been found to reduce the secretion of virulence factors from Pseudomonas aeruginosa. Taken together, the results revealed that in addition to biofilm inhibition, caffeine can also decrease the spreading of virulence factors from Pseudomonas aeruginosa.}, } @article {pmid31772059, year = {2019}, author = {Ma, D and Mandell, JB and Donegan, NP and Cheung, AL and Ma, W and Rothenberger, S and Shanks, RMQ and Richardson, AR and Urish, KL}, title = {The Toxin-Antitoxin MazEF Drives Staphylococcus aureus Biofilm Formation, Antibiotic Tolerance, and Chronic Infection.}, journal = {mBio}, volume = {10}, number = {6}, pages = {}, pmid = {31772059}, issn = {2150-7511}, support = {P30 EY008098/EY/NEI NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Antitoxins/genetics/*metabolism ; Bacterial Proteins/genetics/*metabolism ; Bacterial Toxins/genetics/*metabolism ; *Biofilms/drug effects ; Chronic Disease ; *Drug Resistance, Bacterial ; Female ; Humans ; Male ; Mice ; Mice, Inbred C57BL ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/drug effects/genetics/*physiology ; Toxin-Antitoxin Systems ; }, abstract = {Staphylococcus aureus is the major organism responsible for surgical implant infections. Antimicrobial treatment of these infections often fails, leading to expensive surgical intervention and increased risk of mortality to the patient. The challenge in treating these infections is associated with the high tolerance of S. aureus biofilm to antibiotics. MazEF, a toxin-antitoxin system, is thought to be an important regulator of this phenotype, but its physiological function in S. aureus is controversial. Here, we examined the role of MazEF in developing chronic infections by comparing growth and antibiotic tolerance phenotypes in three S. aureus strains to their corresponding strains with disruption of mazF expression. Strains lacking mazF production showed increased biofilm growth and decreased biofilm antibiotic tolerance. Deletion of icaADBC in the mazF::Tn background suppressed the growth phenotype observed with mazF-disrupted strains, suggesting the phenotype was ica dependent. We confirmed these phenotypes in our murine animal model. Loss of mazF resulted in increased bacterial burden and decreased survival rate of mice compared to its wild-type strain demonstrating that loss of the mazF gene caused an increase in S. aureus virulence. Although lack of mazF gene expression increased S. aureus virulence, it was more susceptible to antibiotics in vivo Combined, the ability of mazF to inhibit biofilm formation and promote biofilm antibiotic tolerance plays a critical role in transitioning from an acute to chronic infection that is difficult to eradicate with antibiotics alone.IMPORTANCE Surgical infections are one of the most common types of infections encountered in a hospital. Staphylococcus aureus is the most common pathogen associated with this infection. These infections are resilient and difficult to eradicate, as the bacteria form biofilm, a community of bacteria held together by an extracellular matrix. Compared to bacteria that are planktonic, bacteria in a biofilm are more resistant to antibiotics. The mechanism behind how bacteria develop this resistance and establish a chronic infection is unknown. We demonstrate that mazEF, a toxin-antitoxin gene, inhibits biofilm formation and promotes biofilm antibiotic tolerance which allows S. aureus to transition from an acute to chronic infection that cannot be eradicated with antibiotics but is less virulent. This gene not only makes the bacteria more tolerant to antibiotics but makes the bacteria more tolerant to the host.}, } @article {pmid31771981, year = {2020}, author = {Anderson, EM and Sychantha, D and Brewer, D and Clarke, AJ and Geddes-McAlister, J and Khursigara, CM}, title = {Peptidoglycomics reveals compositional changes in peptidoglycan between biofilm- and planktonic-derived Pseudomonas aeruginosa.}, journal = {The Journal of biological chemistry}, volume = {295}, number = {2}, pages = {504-516}, pmid = {31771981}, issn = {1083-351X}, support = {PJT 156111//CIHR/Canada ; PJT 156353//CIHR/Canada ; }, mesh = {*Biofilms/growth & development ; Cell Wall/chemistry/metabolism ; Glycomics ; Humans ; Mass Spectrometry ; Peptidoglycan/chemistry/*metabolism ; Plankton/chemistry/*physiology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/chemistry/*physiology ; }, abstract = {Peptidoglycan (PG) is a critical component of the bacterial cell wall and is composed of a repeating β-1,4-linked disaccharide of N-acetylglucosamine and N-acetylmuramic acid appended with a highly conserved stem peptide. In Gram-negative bacteria, PG is assembled in the cytoplasm and exported into the periplasm where it undergoes considerable maturation, modification, or degradation depending on the growth phase or presence of environmental stressors. These modifications serve important functions in diverse processes, including PG turnover, cell elongation/division, and antibiotic resistance. Conventional methods for analyzing PG composition are complex and time-consuming. We present here a streamlined MS-based method that combines differential analysis with statistical 1D annotation approaches to quantitatively compare PGs produced in planktonic- and biofilm-cultured Pseudomonas aeruginosa We identified a core assembly of PG that is present in high abundance and that does not significantly differ between the two growth states. We also identified an adaptive PG assembly that is present in smaller amounts and fluctuates considerably between growth states in response to physiological changes. Biofilm-derived adaptive PG exhibited significant changes compared with planktonic-derived PG, including amino acid substitutions of the stem peptide and modifications that indicate changes in the activity of amidases, deacetylases, and lytic transglycosylases. The results of this work also provide first evidence of de-N-acetylated muropeptides from P. aeruginosa The method developed here offers a robust and reproducible workflow for accurately determining PG composition in samples that can be used to assess global PG fluctuations in response to changing growth conditions or external stimuli.}, } @article {pmid31771575, year = {2019}, author = {Phophi, L and Petzer, IM and Qekwana, DN}, title = {Antimicrobial resistance patterns and biofilm formation of coagulase-negative Staphylococcus species isolated from subclinical mastitis cow milk samples submitted to the Onderstepoort Milk Laboratory.}, journal = {BMC veterinary research}, volume = {15}, number = {1}, pages = {420}, pmid = {31771575}, issn = {1746-6148}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/growth & development ; Cattle ; Coagulase/analysis ; Drug Resistance, Bacterial/*genetics ; Female ; Mastitis, Bovine/epidemiology/*microbiology ; Microbial Sensitivity Tests ; Milk/microbiology ; South Africa/epidemiology ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus/classification/*drug effects/genetics ; }, abstract = {BACKGROUND: Increased prevalence of antimicrobial resistance, treatment failure, and financial losses have been reported in dairy cows with coagulase-negative Staphylococcus (CoNS) clinical mastitis, however, studies on CoNS infections are limited in South Africa. Therefore, the objectives of this study were to investigate the antimicrobial resistance patterns and biofilm formation in CoNS isolated from cow milk samples submitted to the Onderstepoort Milk Laboratory.

RESULTS: A total of 142 confirmed CoNS isolates were used for this study. Biofilm formation was identified in 18% of CoNS tested. Staphylococcus chromogenes (11%) had the highest proportion of biofilm formation followed by S. haemolyticus (4.0%), S. epidermidis, S. hominis, S. xylosus, and S. simulans with 1% respectively. Ninety percent (90%) of CoNS were resistant to at least one antimicrobial (AMR) and 51% were multidrug-resistant (MDR). Resistance among CoNS was the highest to ampicillin (90%) and penicillin (89%), few isolates resistant to cefoxitin and vancomycin, 9% respectively. Similarly, MDR-S. haemolyticus (44%), MDR-S. epidermidis (65%), and MDR-S. chromogenes (52%) were mainly resistant to penicillins. The most common resistance patterns observed were resistance to penicillin-ampicillin (16%) and penicillin-ampicillin-erythromycin (10%). Only 42% of biofilm positive CoNS were MDR.

CONCLUSION: The majority of CoNS in this study were resistance to penicillins. In addition, most isolates were β-lactam resistant and MDR. Biofilm formation among the CoNS in this study was uncommon and there was no significant difference in the proportion of MDR-CoNS based on the ability to form a biofilm.}, } @article {pmid31771160, year = {2019}, author = {Olszak, T and Danis-Wlodarczyk, K and Arabski, M and Gula, G and Maciejewska, B and Wasik, S and Lood, C and Higgins, G and Harvey, BJ and Lavigne, R and Drulis-Kawa, Z}, title = {Pseudomonas aeruginosa PA5oct Jumbo Phage Impacts Planktonic and Biofilm Population and Reduces Its Host Virulence.}, journal = {Viruses}, volume = {11}, number = {12}, pages = {}, pmid = {31771160}, issn = {1999-4915}, mesh = {Biofilms/*growth & development ; Mutation ; Phage Therapy ; Phenotype ; Plankton/*microbiology ; Pseudomonas Phages/genetics/*physiology ; Pseudomonas aeruginosa/genetics/growth & development/pathogenicity/*virology ; Virulence ; }, abstract = {The emergence of phage-resistant mutants is a key aspect of lytic phages-bacteria interaction and the main driver for the co-evolution between both organisms. Here, we analyze the impact of PA5oct jumbo phage treatment on planktonic/cell line associated and sessile P. aeruginosa population. Besides its broad-spectrum activity and efficient bacteria reduction in both airway surface liquid (ASL) model, and biofilm matrix degradation, PA5oct appears to persist in most of phage-resistant clones. Indeed, a high percentage of resistance (20/30 clones) to PA5oct is accompanied by the presence of phage DNA within bacterial culture. Moreover, the maintenance of this phage in the bacterial population correlates with reduced P. aeruginosa virulence, coupled with a sensitization to innate immune mechanisms, and a significantly reduced growth rate. We observed rather unusual consequences of PA5oct infection causing an increased inflammatory response of monocytes to P. aeruginosa. This phenomenon, combined with the loss or modification of the phage receptor, makes most of the phage-resistant clones significantly less pathogenic in in vivo model. These findings provide new insights into the general knowledge of giant phages biology and the impact of their application in phage therapy.}, } @article {pmid31769530, year = {2020}, author = {Ganesh, PS and Vishnupriya, S and Vadivelu, J and Mariappan, V and Vellasamy, KM and Shankar, EM}, title = {Intracellular survival and innate immune evasion of Burkholderia cepacia: Improved understanding of quorum sensing-controlled virulence factors, biofilm, and inhibitors.}, journal = {Microbiology and immunology}, volume = {64}, number = {2}, pages = {87-98}, doi = {10.1111/1348-0421.12762}, pmid = {31769530}, issn = {1348-0421}, mesh = {Animals ; *Biofilms/drug effects/growth & development ; *Burkholderia Infections/etiology/immunology ; Burkholderia cepacia/growth & development/*pathogenicity ; Burkholderia cepacia complex/pathogenicity ; Communicable Diseases, Emerging ; Cross Infection/immunology ; Cystic Fibrosis/complications/immunology/*microbiology ; Cytokine Release Syndrome ; Drug Resistance, Multiple, Bacterial ; Humans ; Immune Evasion ; Immunocompromised Host ; Inflammation ; Lipase/metabolism ; Lipopolysaccharides/metabolism ; Lung/microbiology ; Macrophages/microbiology ; Metalloendopeptidases/metabolism ; Mice ; Neutrophils/immunology ; Quorum Sensing/*immunology ; Siderophores/metabolism ; Virulence Factors/metabolism ; }, abstract = {Burkholderia cepacia complex (Bcc) are opportunistic pathogens implicated with nosocomial infections, and high rates of morbidity and mortality, especially in individuals with cystic fibrosis (CF). B. cepacia are naturally resistant to different classes of antibiotics, and can subvert the host innate immune responses by producing quorum sensing (QS) controlled virulence factors and biofilms. It still remains a conundrum as to how exactly the bacterium survives the intracellular environment within the host cells of CF patients and immunocompromised individuals although the bacterium can invade human lung epithelial cells, neutrophils, and murine macrophages. The mechanisms associated with intracellular survival in the airway epithelial cells and the role of QS and virulence factors in B. cepacia infections in cystic fibrosis remain largely unclear. The current review focuses on understanding the role of QS-controlled virulence factors and biofilms, and provides additional impetus to understanding the potentials of QS-inhibitory strategies against B. cepacia.}, } @article {pmid31769202, year = {2020}, author = {Chen, Q and Xie, S and Lou, X and Cheng, S and Liu, X and Zheng, W and Zheng, Z and Wang, H}, title = {Biofilm formation and prevalence of adhesion genes among Staphylococcus aureus isolates from different food sources.}, journal = {MicrobiologyOpen}, volume = {9}, number = {1}, pages = {e00946}, pmid = {31769202}, issn = {2045-8827}, mesh = {Adhesins, Bacterial/*genetics ; Bacterial Adhesion/*genetics/physiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Food Microbiology ; Foodborne Diseases/microbiology ; Humans ; Staphylococcal Infections ; Staphylococcus aureus/*genetics/metabolism ; }, abstract = {To assess biofilm formation ability and identify differences in the prevalence of genes involved in biofilm formation among Staphylococcus aureus strains isolated from different food samples, the ability of biofilm formation among 97 S. aureus strains was evaluated using a colorimetric microtiter plate assay. Thirteen genes encoding microbial surface components recognizing adhesive matrix molecules, and the intracellular adhesion genes were detected by PCR using specific primers. Approximately 72% of the isolates produced biofilms. Among these isolates, 54.64% were weak biofilm producers, while 14.43% and 3.09% produced moderate and strong biofilms, respectively. The icaADBC, clfA/B, cidA, and fib genes were detected in all the S. aureus strains, whereas the bap gene was not present in any of the strains. The occurrence of other adhesin genes varied greatly between biofilm-producing and nonbiofilm-producing strains. However, a significant difference was observed between these two groups with respect to the fnbpB, cna, ebps, and sdrC genes. No obvious evidence was found to support the link between PFGE strain typing and the capacity for biofilm formation. Considerable variation in biofilm formation ability was observed among S. aureus strains isolated from food samples. The prevalence of adhesin-encoding genes also varied greatly within strains. This study highlights the importance of biofilm formation and the adhesins of S. aureus strains in food samples.}, } @article {pmid31768723, year = {2019}, author = {Fekrirad, Z and Kashef, N and Arefian, E}, title = {Photodynamic inactivation diminishes quorum sensing-mediated virulence factor production and biofilm formation of Serratia marcescens.}, journal = {World journal of microbiology & biotechnology}, volume = {35}, number = {12}, pages = {191}, pmid = {31768723}, issn = {1573-0972}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Hemolysin Proteins/metabolism ; Methylene Blue/metabolism ; Microscopy, Electron, Scanning ; Photochemotherapy/*methods ; Prodigiosin/metabolism ; Quorum Sensing/*radiation effects ; Serratia marcescens/genetics/metabolism/*radiation effects ; Virulence Factors/genetics/*metabolism ; }, abstract = {Serratia marcescens is an opportunistic human pathogen causing nosocomial infections and displays expanded resistance towards the conventional antibiotics. In S. marcescens, quorum sensing (QS) mechanism coordinates the population-dependent behaviors and regulates the virulence factors production. Photodynamic inactivation (PDI) is a promising alternative for the treatment of infections caused by drug resistant bacteria. Although PDI should be applied at lethal doses, it is possible that during PDI treatment, pathogens encounter sub-lethal doses of PDI (sPDI). sPDI cannot kill microorganisms, but it can considerably influence the microbial virulence. So, in this study, the effect of methylene blue (MB)-mediated PDI on QS-mediated virulence factor production and biofilm formation of S. marcescens at lethal and sub-lethal doses was evaluated. The biofilm formation and virulence factor production of S. marcescens ATCC 13,880 and S. marcescens Sm2 were assessed before and after PDI treatment. Besides, the effect of lethal and sub-lethal PDI on expression of bsmA and bsmB (Biofilm maturation), fimA and fimC (Major fimbrial protein), flhD (Regulator of flagellar mediated swarming and swimming motility) and swrR (AHL-dependent regulator) genes were evaluated by quantitative real time polymerase chain reaction. Lethal and sub-lethal PDI resulted in a significant decrease in biofilm formation, swimming/swarming motility, and pigment and hemolysin production ability of S. marcescens strains. bsmA, bsmB, flhD and swrR genes were down-regulated after PDI treatments. In conclusion, QS-mediated virulence factor production and biofilm formation ability of the two studied S. marcescens strains decreased after both lethal and sub-lethal PDI.}, } @article {pmid31768611, year = {2020}, author = {Kischkel, B and Souza, GK and Chiavelli, LUR and Pomini, AM and Svidzinski, TIE and Negri, M}, title = {The ability of farnesol to prevent adhesion and disrupt Fusarium keratoplasticum biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {104}, number = {1}, pages = {377-389}, doi = {10.1007/s00253-019-10233-2}, pmid = {31768611}, issn = {1432-0614}, support = {421620/2018-8//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Chlorocebus aethiops ; Farnesol/*pharmacology ; Fusarium/*drug effects ; HeLa Cells ; Humans ; Hyphae/drug effects ; Quorum Sensing/drug effects ; Spores, Fungal/drug effects ; Vero Cells ; }, abstract = {A biofilm is represented by a community of microorganisms capable of adhering to a surface and producing substances that envelop the cells, forming an extracellular matrix. The extracellular matrix is responsible for protecting microorganisms against environmental stress, hosts the immune system and confers resistance to antimicrobials. Fusarium keratoplasticum is a common species of FSSC (Fusarium solani species complex) associated with human infections, being the most prevalent species related to biofilm formation in hospital water systems and internal pipelines. With this in mind, this study aimed to characterise the biofilm formed by the fungus F. keratoplasticum and to evaluate the effects of farnesol, a fungal quorum sensing (QS) molecule, on the preformed biofilm and also during its formation at different times (adhesion and 24, 48 and 72 h). F. keratoplasticum is able to adhere to an abiotic surface and form a dense biofilm in 72 h, with increased total biomass and matrix modulation with the presence of extracellular DNA, RNA, polysaccharides and proteins. Farnesol exhibited important anti-biofilm activity, causing the destruction of hyphae and the extracellular matrix in preformed biofilm and preventing the adhesion of conidia, filamentation and the formation of biofilm. Few studies have characterised the formation of biofilm by filamentous fungi. Our findings suggest that farnesol acts efficiently on F. keratoplasticum biofilm since this molecule is capable of breaking the extracellular matrix, thereby disarranging the biofilm.}, } @article {pmid31767527, year = {2020}, author = {Vijay, AK and Zhu, H and Willcox, M and Ketelson, H and Stapleton, F}, title = {Bacterial biofilm in silver-impregnated contact lens cases.}, journal = {Contact lens & anterior eye : the journal of the British Contact Lens Association}, volume = {43}, number = {4}, pages = {408-412}, doi = {10.1016/j.clae.2019.11.004}, pmid = {31767527}, issn = {1476-5411}, mesh = {Bacteria ; *Biofilms ; Contact Lens Solutions ; *Contact Lenses ; Humans ; Pseudomonas aeruginosa ; *Silver ; Staphylococcus aureus ; }, abstract = {PURPOSE: This study investigated the efficacy of pre-conditioning lens cases on bacterial biofilm formation and removal.

METHODS: Silver impregnated (MicroBlock / ProGuard™ & i-Clean) and control storage cases were pre-conditioned for 24 h with their respective multipurpose solutions (MPDSs). Cases were then inoculated with 2 ml of 10[6] CFU/mL of ocular isolates of either P. aeruginosa or S. aureus and incubated for 48 h. Cases were subsequently disinfected (4-6 hours) as per the manufacturer's recommended disinfecting time (MRDT) followed by the recommended case hygiene procedures - recapping wet (MicroBlock / ProGuard™ cases only) or rinse and air-dry or rinse, tissue-wipe and air dry (mechanical disruption). Surviving bacteria were enumerated using standard techniques.

RESULTS: Pre-conditioning the MicroBlock / ProGuard™ cases with MPDS significantly reduced biofilm formation (-1.1 log10 CFU, p < 0.01 for P. aeruginosa & -1.3 log10, p < 0.001, CFU for S. aureus) compared to the i-Clean lens cases. Maintaining the MicroBlock / ProGuard™ lens cases wet after the MRDT resulted in partial removal of bacterial biofilms (-2.9 log10 CFU, p < 0.001 for P. aeruginosa and -2.6 log10 CFU, p < 0.001 for S. aureus). Air-drying of all three types of lens storage cases after MRDT significantly reduced the bacterial biofilm (-5.4 log10 CFU, p < 0.001 for P. aeruginosa and -3.5 log10 CFU, p < 0.001 for S. aureus). Mechanical disruption produced the greatest reduction in the levels of bacterial biofilm in all 3 types of lens cases tested (-6.8 log10 CFU, p < 0.001 for P. aeruginosa and -4.5 log10 CFU, p < 0.001 for S. aureus). Synergi MPDS was significantly better than AQuify MPDS in removing bacterial biofilm from all 3 lens case types for case hygiene treatments with an air-drying step.

CONCLUSION: Pre-conditioning of silver-impregnated ProGuard™ lens cases inhibited initial bacterial biofilm formation. Synergi MPDS was more effective than AQuify MPDS in removing bacterial biofilm in silver impregnated cases and tissue-wiping significantly improved biofilm removal.}, } @article {pmid31767091, year = {2019}, author = {Vasileiou, NGC and Cripps, PJ and Ioannidi, KS and Katsafadou, AI and Chatzopoulos, DC and Barbagianni, MS and Tsioli, V and Dermisiadou, E and Karavanis, E and Papadopoulos, N and Lianou, DT and Mavrogianni, VS and Petinaki, E and Fthenakis, GC}, title = {Experimental study for evaluation of the efficacy of a biofilm-embedded bacteria-based vaccine against Staphylococcus chromogenes-associated mastitis in sheep.}, journal = {Veterinary microbiology}, volume = {239}, number = {}, pages = {108480}, doi = {10.1016/j.vetmic.2019.108480}, pmid = {31767091}, issn = {1873-2542}, mesh = {Animals ; Bacterial Vaccines/*standards ; *Biofilms ; Female ; Mammary Glands, Animal/microbiology ; Mastitis/microbiology/pathology/prevention & control/*veterinary ; Milk/cytology/microbiology ; Sheep ; Sheep Diseases/microbiology/*prevention & control ; }, abstract = {Although coagulase-negative staphylococci are the primary aetiological agents of subclinical mastitis in ewes, there is little information regarding vaccination against that infection. The objective of this study was to evaluate the efficacy of a vaccine against staphylococcal mastitis in ewes under experimental conditions. The antigen in the vaccine is based on a bacterin of Staphylococcus aureus strain, expressing the exopolysaccharide poly-N-acetylglucosamine (PNAG), which is involved in biofilm formation by these bacteria. Ewes in groups A (n = 17) or B (n = 6) were given an initial vaccination 5 weeks before expected lambing, followed by a repeat administration 21 days later. Ewes in groups C (n = 8) or D (n = 6) were unvaccinated controls. Ewes in group A (n = 17) or C (n = 8) were challenged with a biofilm-forming S. chromogenes; animals in subgroups A1 or C1 were challenged on the 10th and those in A2 or C2 on the 50th day after lambing. Ewes in groups B or D were uninoculated controls. Clinical examinations of ewes, ultrasonographic examinations of udder, milk yield measurements, blood sampling for detection of anti-PNAG specific antibodies and milk sample collection for bacteriological and cytological examinations were performed up to 52nd day post-challenge. Finally, biopsies were performed for mammary tissue collection for histopathological examination. Among group A ewes, 29% developed systemic signs and 59% signs in the inoculated gland; the respective figures for group C were 50% and 100% (P = 0.040 for mammary signs). The median total clinical score was 2.0 for A and 5.5 for C ewes (P = 0.025). For A, but not for C, clinical scores decreased progressively during the study (P = 0.018 and P = 0.47, respectively). The duration of mastitis was shorter in A (4 days) than in C (17.5 days) ewes (P = 0.022). Bacterial counts were lower in milk samples from A than from C ewes, for samples collected from the inoculated and the uninoculated (P < 0.01) mammary glands of these ewes. Somatic cell counts in samples from inoculated and uninoculated mammary glands of A ewes were higher than in samples of C ewes (P < 0.02). There were differences for gray-scale evaluations during ultrasonographic examination and for milk yield measurements between groups (P < 0.01). Median bacterial counts in tissue samples from A ewes (0 cfu g[-1]) were lower than in ones from C (6.5 cfu g[-1]) ewes (P = 0.041). The median score for histopathological findings in tissue samples from inoculated glands of A was lower than that for C ewes: 1 versus 2 (P = 0.014). It is concluded that mastitis was less severe in vaccinated animals, as indicated by a wide array of measures.}, } @article {pmid31766551, year = {2019}, author = {Fleming, G and Aveyard, J and Fothergill, JL and McBride, F and Raval, R and D'Sa, RA}, title = {Effect of Polymer Demixed Nanotopographies on Bacterial Adhesion and Biofilm Formation.}, journal = {Polymers}, volume = {11}, number = {12}, pages = {}, pmid = {31766551}, issn = {2073-4360}, support = {EP/MO27325/1//Engineering and Physical Sciences Research Council/ ; EP/M027325/1//Engineering and Physical Sciences Research Council/ ; }, abstract = {As the current global threat of antimicrobial resistance (AMR) persists, developing alternatives to antibiotics that are less susceptible to resistance is becoming an urgent necessity. Recent advances in biomaterials have allowed for the development and fabrication of materials with discrete surface nanotopographies that can deter bacteria from adhering to their surface. Using binary polymer blends of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL) and varying their relative concentrations, PS/PCL, PS/PMMA and PCL/PMMA polymer demixed thin films were developed with nanoisland, nanoribbon and nanopit topographies. In the PS/PCL system, PS segregates to the air-polymer interface, with the lower solubility PCL preferring the substrate-polymer interface. In the PS/PMMA and PCL/PMMA systems, PMMA prefers the air-polymer interface due to its greater solubility and lower surface energy. The anti-adhesion efficacy of the demixed films were tested against Pseudomonas aeruginosa (PA14). PS/PCL and PCL/PMMA demixed films showed a significant reduction in cell counts adhered on their surfaces compared to pure polymer control films, while no reduction was observed in the counts adhered on PS/PMMA demixed films. While the specific morphology did not affect the adhesion, a relationship between bacterial cell and topographical surface feature size was apparent. If the surface feature was smaller than the cell, then an anti-adhesion effect was observed; if the surface feature was larger than the cell, then the bacteria preferred to adhere.}, } @article {pmid31766547, year = {2019}, author = {Miao, L and Guo, S and Liu, Z and Liu, S and You, G and Qu, H and Hou, J}, title = {Effects of Nanoplastics on Freshwater Biofilm Microbial Metabolic Functions as Determined by BIOLOG ECO Microplates.}, journal = {International journal of environmental research and public health}, volume = {16}, number = {23}, pages = {}, pmid = {31766547}, issn = {1660-4601}, mesh = {Biofilms ; Carbon/analysis ; Dose-Response Relationship, Drug ; *Fresh Water ; *Nanotechnology ; Particle Size ; Plastics/*pharmacology ; *Water Microbiology ; }, abstract = {Nanoplastic (NP) contamination is becoming a pervasive issue as NPs, originating from microplastic particles, pose potentially harmful environmental impacts on aquatic ecosystems. The environmental hazards of NPs on microorganisms have been well documented in recent studies; however, little is known about their ecotoxicity effects on freshwater biofilms, which serve as important primary producers and decomposers and are highly connected with other ecosystem components. We investigated the effects of NPs on the microbial metabolic functions of freshwater biofilms in terms of carbon source utilization ability. Biofilm samples were collected, cultivated in a hydrodynamic flume for six weeks, and then exposed in polystyrene (PS) beads (100 nm in size) with different NP concentrations (1, 5, and 10 mg/L). BIOLOG ECO microplates were used to quantify carbon source utilization characteristics. The data were analyzed using average well-color development (AWCD), functional diversity indices, and principle component analysis (PCA). Results showed that the total carbon metabolic functions (represented by AWCD) remained constant (p > 0.05) with elevated NP concentrations, but some specific carbon sources (e.g., esters) changed in their utilization ability (p < 0.05). The microbial functional diversity (Shannon-Wiener diversity index, Simpson diversity index, and Shannon evenness index) was significantly reduced under 10 mg/L NPs (p < 0.05), indicating an inhibiting effect of NPs on biofilm metabolic diversity. This study examined NP ecotoxicity effects on microbial metabolic activities at the community level, but further studies are required to fully understand the mechanisms driving this change.}, } @article {pmid31766008, year = {2020}, author = {Xu, Y and Dhaouadi, Y and Stoodley, P and Ren, D}, title = {Sensing the unreachable: challenges and opportunities in biofilm detection.}, journal = {Current opinion in biotechnology}, volume = {64}, number = {}, pages = {79-84}, pmid = {31766008}, issn = {1879-0429}, support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R21 AI142424/AI/NIAID NIH HHS/United States ; }, mesh = {*Bacteria ; *Biofilms ; }, abstract = {Bacteria can attach to essentially all materials and form multicellular biofilms with high-level tolerance to antimicrobials. Detrimental biofilms are responsible for a variety of problems ranging from food and water contamination, bio-corrosion, to drug resistant infections. Besides the challenges in control, biofilms are also difficult to detect due to the lack of biofilm-specific biomarkers and methods for non-destructive imaging. In this article, we present a concise review of recent advancements in this field, with a focus on medical device-associated infections. We also discuss the technologies that have potential for non-destructive detection of bacterial biofilms.}, } @article {pmid31762509, year = {2019}, author = {Yaikhan, T and Chuerboon, M and Tippayatham, N and Atimuttikul, N and Nuidate, T and Yingkajorn, M and Tun, AW and Buncherd, H and Tansila, N}, title = {Indole and Derivatives Modulate Biofilm Formation and Antibiotic Tolerance of Klebsiella pneumoniae.}, journal = {Indian journal of microbiology}, volume = {59}, number = {4}, pages = {460-467}, pmid = {31762509}, issn = {0046-8991}, abstract = {Intercellular communication is a crucial process for the multicellular community in both prokaryotes and eukaryotes. Indole has been recognized as a new member of the signal molecules which enables the regulated control of various bacterial phenotypes. To elucidate the inter-species relationship among enteric microorganisms via indole signaling, Klebsiella pneumoniae (KP) culture was treated with indole solution and examined for the pathogenicity by using various phenotypic tests. Both synthetic and naturally-produced indole preparations had no deteriorating effect on growth and autoaggregative capacity of KP. The results showed that biofilm formation of carbapenem-susceptible K. pneumoniae (KP-S) was clearly induced by indole exposure (≈ 2-10 folds), whereas no significant difference was observed in the resistant counterpart. In addition, the tolerance to β-lactam antibiotics of KP was altered upon exposure to indole and/or derivatives assessed by Kirby-Bauer disk diffusion test. Taken together, our finding indicates the functional role of indole in changing or modulating pathogenic behaviors of other bacteria.}, } @article {pmid31762256, year = {2020}, author = {Liu, XY and Guo, S and Ramoji, A and Bocklitz, T and Rösch, P and Popp, J and Yu, HQ}, title = {Spatiotemporal Organization of Biofilm Matrix Revealed by Confocal Raman Mapping Integrated with Non-negative Matrix Factorization Analysis.}, journal = {Analytical chemistry}, volume = {92}, number = {1}, pages = {707-715}, doi = {10.1021/acs.analchem.9b02593}, pmid = {31762256}, issn = {1520-6882}, mesh = {Algorithms ; *Biofilms ; Escherichia coli/*metabolism ; Multivariate Analysis ; Spectrum Analysis, Raman ; }, abstract = {Biofilms are microbial aggregates of microorganisms surrounded by a hydrogel-like matrix formed by extracellular polymeric substances (EPS). The formation of biofilms is intrinsically complex, from the attachment of microbial cells to the dispersion of the biofilm. Meanwhile, the three-dimensional framework built up by EPS changes with time and protects the microorganisms against environmental stress. Simultaneously acquiring chemical and structural information within the biofilm matrix is vital for the cognition and regulation of biofilms, yet it remains a great challenge due to the sample complexity and the limited approaches. In this study, confocal Raman microscopy and non-negative matrix factorization (NMF) analysis were combined to investigate spatiotemporal organization of Escherichia coli biofilms during development at molecular-level detail. The alternating non-negative least-squares (ANLS) approach was incorporated with the sequential coordinate-wise descent (SCD) algorithm to realize the NMF analysis for the large-scale hyperspectral data set. As a result, three components, including bacteria, protein, and polyhydroxybutyrate (PHB), were successfully resolved from the spectra of E. coli biofilm. Furthermore, the structural changes of biofilms could be visualized and quantified by their abundances derived from the NMF analysis, which might be related to the nutrient and oxygen gradient and physiological functions. This methodology provides a comprehensive understanding of the chemical constituents and their spatiotemporal distribution within the biofilm matrix. Furthermore, it also shows great potential for the analysis of unknown and complex biological samples with 3D Raman mapping.}, } @article {pmid31759700, year = {2020}, author = {Dai, C and Bin, L and Tang, B and Li, P and Huang, S and Fu, F and Yin, Q}, title = {Promoting the granulation process of aerobic granular sludge in an integrated moving bed biofilm-membrane bioreactor under a continuous-flowing mode.}, journal = {The Science of the total environment}, volume = {703}, number = {}, pages = {135482}, doi = {10.1016/j.scitotenv.2019.135482}, pmid = {31759700}, issn = {1879-1026}, mesh = {Aerobiosis ; Biodegradation, Environmental ; Biofilms ; *Bioreactors ; Sewage ; *Waste Disposal, Fluid ; }, abstract = {This investigation demonstrated that aerobic granular sludge (AGS) could be cultivated rapidly in a single continuous-flowing membrane bioreactor (MBR) by introducing freely moved bio-carriers with a filling ratio of 10%. By operating the bioreactor for 28 days, AGS was successfully cultivated and kept stable for >2 months with a compact structure and clear shape, in which, extracellular polymeric substances played a key role in maintaining the stability of granular sludge structure. The microbial composition between AGS and attached biofilm was quite different, which indicated that the introduced bio-carriers improved the biodiversity within the bioreactor. Additionally, an explicit internal circulation was formed by the introduced bio-carriers, which was the main reason leading to the rapid formation of AGS. This is an interesting discovery and a novel approach to promote the rapid granulation of biomass in an MBR. Moreover, combining the biodegradation of AGS and filtration of membrane module, the bio-reactor achieved an excellent performance in removing CODCr (>90%) and TN (>85%) during the whole process.}, } @article {pmid31758171, year = {2020}, author = {Casagrande Pierantoni, D and Roscini, L and Corte, L and Bernardo, M and Bassetti, M and Tascini, C and Cardinali, G}, title = {Qualitative and quantitative change of the tolerance to liposomal amphotericin B triggered by biofilm maturation in C. parapsilosis.}, journal = {Medical mycology}, volume = {58}, number = {6}, pages = {827-834}, doi = {10.1093/mmy/myz113}, pmid = {31758171}, issn = {1460-2709}, mesh = {Amphotericin B/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Biomass ; Candida parapsilosis/*drug effects/growth & development ; Microbial Sensitivity Tests ; }, abstract = {Candida parapsilosis is an emerging opportunistic pathogen present in both clinical and natural environment, with a strong frequency of biofilm forming strains. While the drugs active against biofilm are rare, liposomal amphotericin B is credited with an antibiofilm activity in some opportunistic species of the genus Candida. Using freshly isolated strains from hospital environment, in this paper we could show the prevalence of biofilm forming vs. nonbiofilm forming strains. The former displayed a large variability in terms of biofilm biomass and metabolic activity. Liposomal amphotericin B minimum inhibitory concentration (MIC) of planktonic cells was below the breakpoint, whereas the sessile cells MIC (SMIC) was 1 or 2 orders of magnitude above the planktonic MIC. When the drug was applied to freshly attached cells, that is, biofilm in formation, the MIC (called SDMIC) was even below the MIC value. All resistance metrics (MIC, SMIC, and SDMIC) were quite variable although no correlation could be detected between them and the metrics used to quantify biofilm activity and biomass production. These findings demonstrate that young biofilm cells are even more susceptible than planktonic cells and that early treatments with this drug can be beneficial in cases of prosthesis implantation or especially when there is the necessity of a CVC reimplantation during a sepsis.}, } @article {pmid31757539, year = {2020}, author = {Xiao, W and Xu, G}, title = {Mass transfer of nanobubble aeration and its effect on biofilm growth: Microbial activity and structural properties.}, journal = {The Science of the total environment}, volume = {703}, number = {}, pages = {134976}, doi = {10.1016/j.scitotenv.2019.134976}, pmid = {31757539}, issn = {1879-1026}, mesh = {Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors ; Extracellular Polymeric Substance Matrix ; Waste Disposal, Fluid/*methods ; Wastewater ; }, abstract = {It is necessary to improve the performance and reduce the aeration cost is of wastewater treatment by aerobic biofilm systems. Nanobubble aeration is supposed to be a promising method to achieve these goals. Compared with coarse bubbles, dissolved oxygen profiling showed that the nanobubbles provided more oxygen to biofilms, offering superior oxygen supply capacity and 1.5 times higher oxygen transfer efficiency. Nanobubble aeration accelerated the growth of the biofilm and achieved better removal efficiencies of chemical oxygen demand and ammonia, with as maximum as six times higher dehydrogenase activity, and more extracellular polymeric substance content than when using the traditional aeration mode. This is attributed to the enhancement of metabolism and the proliferation of microorganisms. Confocal laser-scanning microscopy imaging confirmed that nanobubble aeration affected the components of biofilm by shifting the microbial community and changing its metabolic pathways of biofilms, such as carbohydrate synthesis. Nanobubble aeration resulted in an energy saving of approximately 80%. The assessment of nanobubble aerated biofilm growth suggests that this technique can offer a rapid-initiation, high efficiency, and low-cost strategy for aerobic biofilm systems in wastewater treatment.}, } @article {pmid31756969, year = {2019}, author = {Hiltunen, AK and Savijoki, K and Nyman, TA and Miettinen, I and Ihalainen, P and Peltonen, J and Fallarero, A}, title = {Structural and Functional Dynamics of Staphylococcus aureus Biofilms and Biofilm Matrix Proteins on Different Clinical Materials.}, journal = {Microorganisms}, volume = {7}, number = {12}, pages = {}, pmid = {31756969}, issn = {2076-2607}, support = {Personal grant to A.H.//Finnish Pharmaceutical Society/ ; Personal grant to A.H.//DOCTORAL PROGRAMME IN DRUG RESEARCH (DPDR)/ ; Research Grant awarded to A.F.//JANE AND AATOS ERKKO FOUNDATION/ ; 272266, 282981, 292646, 272363//Academy of Finland/ ; }, abstract = {Medical device-associated staphylococcal infections are a common and challenging problem. However, detailed knowledge of staphylococcal biofilm dynamics on clinically relevant surfaces is still limited. In the present study, biofilm formation of the Staphylococcus aureus ATCC 25923 strain was studied on clinically relevant materials-borosilicate glass, plexiglass, hydroxyapatite, titanium and polystyrene-at 18, 42 and 66 h. Materials with the highest surface roughness and porosity (hydroxyapatite and plexiglass) did not promote biofilm formation as efficiently as some other selected materials. Matrix-associated poly-N-acetyl-β-(1-6)-glucosamine (PNAG) was considered important in young (18 h) biofilms, whereas proteins appeared to play a more important role at later stages of biofilm development. A total of 460 proteins were identified from biofilm matrices formed on the indicated materials and time points-from which, 66 proteins were proposed to form the core surfaceome. At 18 h, the appearance of several r-proteins and glycolytic adhesive moonlighters, possibly via an autolysin (AtlA)-mediated release, was demonstrated in all materials, whereas classical surface adhesins, resistance- and virulence-associated proteins displayed greater variation in their abundances depending on the used material. Hydroxyapatite-associated biofilms were more susceptible to antibiotics than biofilms formed on titanium, but no clear correlation between the tolerance and biofilm age was observed. Thus, other factors, possibly the adhesive moonlighters, could have contributed to the observed chemotolerant phenotype. In addition, a protein-dependent matrix network was observed to be already well-established at the 18 h time point. To the best of our knowledge, this is among the first studies shedding light into matrix-associated surfaceomes of S. aureus biofilms grown on different clinically relevant materials and at different time points.}, } @article {pmid31756896, year = {2019}, author = {Rodríguez-Campos, D and Rodríguez-Melcón, C and Alonso-Calleja, C and Capita, R}, title = {Persistent Listeria monocytogenes Isolates from a Poultry-Processing Facility Form more Biofilm but Do Not Have a Greater Resistance to Disinfectants Than Sporadic Strains.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31756896}, issn = {2076-0817}, support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; }, abstract = {Some strains of Listeria monocytogenes can persist in food-processing environments, increasing the likelihood of the contamination of foodstuffs. To identify traits that contribute to bacterial persistence, a selection of persistent and sporadic L. monocytogenes isolates from a poultry-processing facility was investigated for biofilm-forming ability (crystal violet assay). The susceptibility of sessile cells to treatments (five minutes) with sodium hypochlorite having 10% active chlorine (SHY: 10,000 ppm, 25,000 ppm, and 50,000 ppm) and benzalkonium chloride (BZK: 2500 ppm, 10,000 ppm, and 25,000 ppm) was also studied. All isolates exhibited biofilm formation on polystyrene. Persistent strains showed larger (p < 0.001) biofilm formation (OD580 = 0.301 ± 0.097) than sporadic strains (OD580 = 0.188 ± 0.082). A greater susceptibility to disinfectants was observed for biofilms of persistent strains than for those of sporadic strains. The application of SHY reduced biofilms only for persistent strains. BZK increased OD580 in persistent strains (2500 ppm) and in sporadic strains (all concentrations). These results indicate that the use of BZK at the concentrations tested could represent a public health risk. Findings in this work suggest a link between persistence and biofilm formation, but do not support a relationship between persistence and the resistance of sessile cells to disinfectants.}, } @article {pmid31756873, year = {2019}, author = {Lee, J and Alrashed, W and Engel, K and Yoo, K and Neufeld, JD and Lee, HS}, title = {Methane-based denitrification kinetics and syntrophy in a membrane biofilm reactor at low methane pressure.}, journal = {The Science of the total environment}, volume = {695}, number = {}, pages = {133818}, doi = {10.1016/j.scitotenv.2019.133818}, pmid = {31756873}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors/microbiology ; Denitrification ; Methane/*metabolism ; Waste Disposal, Fluid/methods ; Wastewater/microbiology ; }, abstract = {A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low pressure of 0.003 atm. The nitrate concentration was reduced from 20 to 4 mg/L with a low methane concentration of 3.3 mg/L in the effluent at 4 h hydraulic retention time (HRT). An in situ dissolved oxygen sensor showed a concentration of 0.045 mg/L in the MBfR, demonstrating methane oxidation under hypoxic conditions. Both 16S rRNA gene sequencing and metagenomic analysis identified bacteria capable of oxidation of methane coupled to denitrification (Methylocystis), whereas other bacteria were implicated in either methane oxidation (Methylococcus) or nitrate reduction (Escherichia). Reduced genetic potential for nitrate reduction to nitrite at a shorter HRT coincided with a decreased efficiency of denitrification, suggesting rate limitation by this initial step of denitrification. Genes encoding nitrite reduction to dinitrogen were at similar relative abundance under both HRT conditions. Our results provide mechanistic evidence for microbial syntrophy between aerobic methanotrophs and denitrifiers in methane-fed MBfRs operated under varying HRTs, with important implications for novel biological nitrogen removal to dilute wastewater.}, } @article {pmid31754470, year = {2019}, author = {Davidson, DJ and Spratt, D and Liddle, AD}, title = {Implant materials and prosthetic joint infection: the battle with the biofilm.}, journal = {EFORT open reviews}, volume = {4}, number = {11}, pages = {633-639}, pmid = {31754470}, issn = {2058-5241}, abstract = {Prosthetic joint infection (PJI) is associated with poor clinical outcomes and is expensive to treat.Although uncommon overall (affecting between 0.5% and 2.2% of cases), PJI is one of the most commonly encountered complications of joint replacement and its incidence is increasing, putting a significant burden on healthcare systems.Once established, PJI is extremely difficult to eradicate as bacteria exist in biofilms which protect them from antibiotics and the host immune response.Improved understanding of the microbial pathology in PJI has generated potential new treatment strategies for prevention and eradication of biofilm associated infection including modification of implant surfaces to prevent adhesion of bacteria.Much research is currently ongoing looking at different implant surface coatings and modifications, and although most of this work has not translated into clinical medicine there has been some early clinical success. Cite this article: EFORT Open Rev 2019;4:633-639. DOI: 10.1302/2058-5241.4.180095.}, } @article {pmid31753409, year = {2020}, author = {Zhang, ZY and Sun, Y and Zheng, YD and He, W and Yang, YY and Xie, YJ and Feng, ZX and Qiao, K}, title = {A biocompatible bacterial cellulose/tannic acid composite with antibacterial and anti-biofilm activities for biomedical applications.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {106}, number = {}, pages = {110249}, doi = {10.1016/j.msec.2019.110249}, pmid = {31753409}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cellulose/*chemistry ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/drug effects ; Tannins/*chemistry ; }, abstract = {Biofilm-associated infections are in a high rate of recurrence and biofilms show formidable resistance to current antibiotics, making them a growing challenge in biomedical field. In this study, a biocompatible composite was developed by incorporating tannic acid (TA) and MgCl2 to bacterial cellulose (BC) for antimicrobial and anti-biofilm purposes. The morphology was investigated by scanning electron microscopy (SEM), and chemical structure were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). In vitro release profiles of tannic acid revealed that the Mg[2+] cross-links help impede the release of TA from BC matrix, while composite BC-TA lacked Mg[2+] ionic cross-links, thus more TA was released from the hydrogel. The BC-TA-Mg composites also displayed strong antibacterial activity against S. aureus, E. coli and P. aeruginosa. Moreover, the composites significantly reduced biofilm formation of S. aureus and P. aeruginosa after 24 h incubation by ∼80% and ∼87%, respectively. As a consequence, the BC-TA-Mg composites are a very promising material for combating biofilm-associated infections in biomedical and public health fields.}, } @article {pmid31752996, year = {2019}, author = {Deveaux, W and Selvarajoo, K}, title = {Searching for simple rules in Pseudomonas aeruginosa biofilm formation.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {763}, pmid = {31752996}, issn = {1756-0500}, mesh = {Anti-Bacterial Agents/*pharmacology ; Azithromycin/*pharmacology ; Biofilms/drug effects/*growth & development ; Biological Evolution ; Cell Movement ; *Computer Simulation ; Pseudomonas aeruginosa/drug effects/*physiology ; Spatio-Temporal Analysis ; }, abstract = {OBJECTIVE: Living cells display complex and non-linear behaviors, especially when posed to environmental threats. Here, to understand the self-organizing cooperative behavior of a microorganism Pseudomonas aeruginosa, we developed a discrete spatiotemporal cellular automata model based on simple physical rules, similar to Conway's game of life.

RESULTS: The time evolution model simulations were experimentally verified for P. aeruginosa biofilm for both control and antibiotic azithromycin (AZM) treated condition. Our model suggests that AZM regulates the single cell motility, thereby resulting in delayed, but not abolished, biofilm formation. In addition, the model highlights the importance of reproduction by cell to cell interaction is key for biofilm formation. Overall, this work highlights another example where biological evolutionary complexity may be interpreted using rules taken from theoretical disciplines.}, } @article {pmid31752382, year = {2019}, author = {Reza, A and Sutton, JM and Rahman, KM}, title = {Effectiveness of Efflux Pump Inhibitors as Biofilm Disruptors and Resistance Breakers in Gram-Negative (ESKAPEE) Bacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31752382}, issn = {2079-6382}, abstract = {Antibiotic resistance represents a significant threat to the modern healthcare provision. The ESKAPEE pathogens (Enterococcus faecium., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli), in particular, have proven to be especially challenging to treat, due to their intrinsic and acquired ability to rapidly develop resistance mechanisms in response to environmental threats. The development of biofilm has been characterised as an essential contributing factor towards antimicrobial-resistance and tolerance. Several studies have implicated the involvement of efflux pumps in antibiotic resistance, both directly, via drug extrusion and indirectly, through the formation of biofilm. As a result, the underlying mechanism of these pumps has attracted considerable interest due to the potential of targeting these protein structures and developing novel adjunct therapies. Subsequent investigations have revealed the ability of efflux pump-inhibitors (EPIs) to block drug-extrusion and disrupt biofilm formation, thereby, potentiating antibiotics and reversing resistance of pathogen towards them. This review will discuss the potential of EPIs as a possible solution to antimicrobial resistance, examining different challenges to the design of these compounds, with an emphasis on Gram-negative ESKAPEE pathogens.}, } @article {pmid31750272, year = {2019}, author = {I H, SS and F A, J and H H, Y and M E, M}, title = {Evaluation of Wi-Fi Radiation Effects on Antibiotic Susceptibility, Metabolic Activity and Biofilm Formation by Escherichia Coli 0157H7, Staphylococcus Aureus and Staphylococcus Epidermis.}, journal = {Journal of biomedical physics & engineering}, volume = {9}, number = {5}, pages = {579-586}, pmid = {31750272}, issn = {2251-7200}, abstract = {BACKGROUND: The radiation emitted from electromagnetic fields (EMF) can cause biological effects on prokaryotic and eukaryotic cells, including non-thermal effects.

OBJECTIVE: The present study evaluated the non-thermal effects of wireless fidelity (Wi-Fi) operating at 2.4 GHz part of non-ionizing EMF on different pathogenic bacterial strains (Escherichia coli 0157H7, Staphylococcus aureus, and Staphylococcus epidermis). Antibiotic resistance, motility, metabolic activity and biofilm formation were examined.

MATERIAL AND METHODS: In this case-control, a Wi-Fi router was used as a source of microwaves and also bacterial cells were exposed to Wi-Fi radiation continuously for 24 and 48 hours. The antibiotic susceptibility was carried out using a disc diffusion method on Müller Hinton agar plates. Motility of Escherichia coli 0157H7 was conducted on motility agar plates. Cell metabolic activity and biofilm formation were performed using 3-(4, 5-Dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and crystal violet quantification, respectively.

RESULTS: The exposure to Wi-Fi radiation altered motility and antibiotic susceptibility of Escherichia coli 0157H7. However, there was no effect Wi-Fi radiation on antibiotic susceptibility of Staphylococcus aureus and Staphylococcus epidermis. On the other hand, the exposed cells, as compared to the unexposed control, showed an increased metabolic activity and biofilm formation ability in Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis.

CONCLUSION: These results proposed that Wi-Fi exposure acted on bacteria in stressful manner by increasing antibiotic resistance and motility of Escherichia coli 0157H7, as well as enhancing biofilm formation by Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis. The findings may have implications for the management of serious diseases caused by these infectious bacteria.}, } @article {pmid31749946, year = {2019}, author = {Loiola, ABA and Aires, CP and Curylofo-Zotti, FA and Rodrigues Junior, AL and Souza-Gabriel, AE and Corona, SAM}, title = {The Impact of CO2 Laser Treatment and Acidulated Phosphate Fluoride on Enamel Demineralization and Biofilm Formation.}, journal = {Journal of lasers in medical sciences}, volume = {10}, number = {3}, pages = {200-206}, pmid = {31749946}, issn = {2008-9783}, abstract = {Introduction: This study evaluated the impact of CO2 laser treatment and acidulated phosphate fluoride (APF) on enamel demineralization and biofilm formation, using in vitro and in situ designs. Methods: Demineralized enamel slabs were distributed among 8 groups: placebo, placebo + continuous CO2 laser, placebo + repeated CO2 laser, placebo + ultrapulsed CO2 laser, 1.23% APF, APF + continuous CO2 laser, APF + repeated CO2 laser and APF + ultrapulsed CO2 laser. In the in vitro study, 15 enamel slabs from each group were subjected to a pH-cycling regimen for 14 days. In the cross over in situ design, 11 volunteers wore palatal appliances with demineralized enamel slabs for 2 periods of 14 days each. Drops of sucrose solution were dripped onto enamel slabs 8×/day. Biofilms formed on slabs were collected and the colony-forming units (CFU) of Streptococcus mutans and Lactobacillus were determined. Results: For both in vitro and in situ studies, there was no significant difference between treatments (P>0.05). However, all treatments increased microhardness of demineralized enamel (P<0.05). After a further in situ cariogenic challenge, with the exception of the placebo, all treatments maintained microhardness values (P<0.05). Microbiological analysis showed no difference in Streptococcus mutans (P>0.05) or Lactobacillus (P>0.05) counts between groups. Conclusion: The results suggest that APF gel combined with the CO2 laser, regardless of the pulse emission mode used, was effective in controlling enamel demineralization, but none of the tested treatments was able to prevent bacterial colonization.}, } @article {pmid31747498, year = {2019}, author = {Kharseeva, GG and Alieva, AA and Alekseeva, LP and Mangutov, YO and Shovkun, LA}, title = {[Cypopathic effect of diphtheria pathogen in the composition of biofilm.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {64}, number = {11}, pages = {681-685}, doi = {10.18821/0869-2084-2019-64-11-681-685}, pmid = {31747498}, issn = {0869-2084}, mesh = {Animals ; Asymptomatic Infections ; *Biofilms ; CHO Cells ; Corynebacterium diphtheriae/*pathogenicity ; Cricetulus ; *Diphtheria ; Diphtheria Toxin ; Humans ; }, abstract = {When the nasopharynx is colonized with toxigenic strains of the diphtheria pathogen, toxin is released, which contributes to the death of epithelial cells. But in bacterial carriers, the development of the clinical picture of the disease does not occur. This is due to the peculiarities of the state of their immune system, as well as the peculiarities of the production of diphtheria exotoxin by corynebacteria in the biofilm. Goal. Determining the nature of the cytopathic effect of C. diphtheriae as part of a biofilm in CHO-K1 cell culture. The planktonic and biofilm (120- and 720-hour) cultures of the strains were studied: C. diphtheriae gravis tox[+] № 665, C. diphtheriae gravis tox[+] № 6765, C. diphtheriae mitis tox[+] № 269, C. diphtheriae gravis tox[+] isolated from a patient with a diagnosis Localized oropharyngeal diphtheria C. diphtheriae gravis with a silent tox-gene. Biofilm (120- and 720-hour) cultures of diphtheria pathogen strains were obtained according to the Watnik method. The cytopathic effect of corynebacterial strains was studied on a CHO-K1 cell culture, taking into account in an inverted microscope. When studying the cytopathic effect of planktonic cultures of toxigenic strains of corynebacteria, it was found that the number of living CHO-K1 cells after 24 hours was insignificant (25.3±1.2%) and sharply decreased (2.5±0.5%) after 72 hours of cultivation. Under the influence of biofilm and, especially, 720-hour cultures, a different cytopathic effect dynamics was found: the number of living cells after 24 hours remained significant (82.5±2.2%), while at 72-hour it decreased to 25.0±3.0%. In the study of filtrates of planktonic and biofilm cultures of C. diphtheriae strain with a «silent» tox-gene, similar patterns were revealed. However, the number of live CHO-K1 cells when exposed to the filtrate of a 720-hour biofilm culture was significantly higher (p≤0.05) than when studying toxigenic strains of corynebacteria. Considering the nature of the cytopathic action, it was found that planktonic cultures of toxigenic strains of corynebacteria are characterized by a change in the cell monolayer, manifested by their thinning and elongation. The study of 720-hour biofilm cultures at 72-hour exposure revealed the appearance of a large number of rounded cells (63-69%). The cytopathic effect, formed under the influence of filtrates of planktonic and biofilm cultures of C. diphtheriae with a «silent» tox-gene, as well as strains of non-diphtheria corynebacteria, is characterized by rounding of cells and the formation of symplasts. In the biofilm, the intensity of the cytopathic effect of toxigenic C. diphtheriae strains and C. diphtheriae strain with a silent tox-gene decreased. CPD, manifested by thinning and lengthening of CHO-K1 cells, is associated with the action of diphtheria exotoxin, and rounding is associated with corynebacterial enzymes and, apparently, fragments of surface structures - adhesins. Decreased release of toxin and enzymes beyond the C. bihfilm matrix is a significant cause of the «asymptomatic» carriage of diphtheria.}, } @article {pmid31744920, year = {2019}, author = {Esoda, CN and Kuehn, MJ}, title = {Pseudomonas aeruginosa Leucine Aminopeptidase Influences Early Biofilm Composition and Structure via Vesicle-Associated Antibiofilm Activity.}, journal = {mBio}, volume = {10}, number = {6}, pages = {}, pmid = {31744920}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; Cystic Fibrosis/complications ; Epithelial Cells/microbiology ; Extracellular Vesicles/*metabolism ; Gene Deletion ; Host-Pathogen Interactions ; Humans ; Klebsiella pneumoniae/genetics/metabolism ; Leucyl Aminopeptidase/*metabolism ; Protease Inhibitors/pharmacology ; Pseudomonas Infections/*metabolism/*microbiology ; Pseudomonas aeruginosa/drug effects/*enzymology/genetics ; }, abstract = {Pseudomonas aeruginosa, known as one of the leading causes of disease in cystic fibrosis (CF) patients, secretes a variety of proteases. These enzymes contribute significantly to P. aeruginosa pathogenesis and biofilm formation in the chronic colonization of CF patient lungs, as well as playing a role in infections of the cornea, burn wounds, and chronic wounds. We previously characterized a secreted P. aeruginosa peptidase, PaAP, that is highly expressed in chronic CF isolates. This leucine aminopeptidase is highly expressed during infection and in biofilms, and it associates with bacterial outer membrane vesicles (OMVs), structures known to contribute to virulence mechanisms in a variety of Gram-negative species and one of the major components of the biofilm matrix. We hypothesized that PaAP may play a role in P. aeruginosa biofilm formation. Using a lung epithelial cell/bacterial biofilm coculture model, we show that PaAP deletion in a clinical P. aeruginosa background alters biofilm microcolony composition to increase cellular density, while decreasing matrix polysaccharide content, and that OMVs from PaAP-expressing strains but not PaAP alone or in combination with PaAP deletion strain-derived OMVs could complement this phenotype. We additionally found that OMVs from PaAP-expressing strains could cause protease-mediated biofilm detachment, leading to changes in matrix and colony composition. Finally, we showed that the OMVs could also mediate the detachment of biofilms formed by both nonself P. aeruginosa strains and Klebsiella pneumoniae, another respiratory pathogen. Our findings represent novel roles for OMVs and the aminopeptidase in the modulation of P. aeruginosa biofilm architecture.IMPORTANCE Biofilm formation by the bacterial pathogen P. aeruginosa is known to contribute to drug resistance in nosocomial infections and chronic lung infections of cystic fibrosis patients. In order to treat these infections more successfully, the mechanisms of bacterial biofilm development must be elucidated. While both bacterially secreted aminopeptidase and outer membrane vesicles have been shown to be abundant in P. aeruginosa biofilm matrices, the contributions of each of these factors to the steps in biofilm generation have not been well studied. This work provides new insight into how these bacterial components mediate the formation of a robust, drug-resistant extracellular matrix and implicates outer membrane vesicles as active components of biofilm architecture, expanding our overall understanding of P. aeruginosa biofilm biology.}, } @article {pmid31742958, year = {2019}, author = {Godovalov, AP and Karpunina, TI}, title = {[The determination of biofilm composition of gram-positive bacteria.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {64}, number = {10}, pages = {632-634}, doi = {10.18821/0869-2084-2019-64-10-632-634}, pmid = {31742958}, issn = {0869-2084}, support = {17-44-590404 р_а//The Russian Foundation for Basic Research/ ; }, mesh = {*Biofilms ; Gram-Positive Bacteria/*classification ; Staining and Labeling ; }, abstract = {Current methods of biofilm imaging do not support a differentiated assessment of its composition, since it is not possible to establish a substrate stained with crystal violet, as this dye can form complexes with both intracellular and extracellular structures. This approach does not adequately assess the anti-biofilm effects of drugs, while the results of studying the interaction of drugs with biofilm components can ensure their most correct choice. The aim of investigation was to study the possibility of applying the original modification of the current method to determine the ratio of the cellular part and the matrix of biofilms of gram-positive microorganisms. The biofilm components were analyzed using a two-step approach, when prepared biofilms of gram-positive microorganisms were stained with crystal violet for 5 minutes, followed by fixing the dye in bacterial cells with iodine solution, and then the colored products were dissolved with 95% alcohol: matrix components for 1 minute, total biofilm for 15 minutes, after which the composition of biofilms was estimated by the formula: M=(OP1/OP15)×100, Kb=100-M, where M is the proportion of the matrix,%; Kb - the proportion of the cellular component,%; OP1 - optical density of samples, when alcohol was allowed to dissolve the colored product for no more than 1 minute; OP15 - was the optical density of samples, when alcohol is allowed to dissolve the colored product for 15 minutes. It was shown that in the composition of the biofilm formed by the collection strain, the proportion of the matrix was 13.2%, and the cellular component accounted for 86.8%. When the same strain cultivated in the presence of an antibiotic, an increase in the biofilm matrix was observed, which is probably due to the compensatory response of the microorganism to the action of the antibiotic. The proposed approach to the study of biofilms makes it possible to evaluate its component composition. Obtaining additional information in this way can provide, inter alia, an increase in the effectiveness of antimicrobial therapy while reducing the study time.}, } @article {pmid31741645, year = {2019}, author = {Rahdar, HA and Malekabad, ES and Dadashi, AR and Takei, E and Keikha, M and Kazemian, H and Karami-Zarandi, M}, title = {Correlation between biofilm formation and carbapenem resistance among clinical isolates of Klebsiella pneumoniae.}, journal = {Ethiopian journal of health sciences}, volume = {29}, number = {6}, pages = {745-750}, pmid = {31741645}, issn = {2413-7170}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Carbapenems/*therapeutic use ; Drug Resistance, Bacterial/*drug effects ; Humans ; Klebsiella Infections/*drug therapy/*physiopathology ; Klebsiella pneumoniae/*isolation & purification ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is a Gram-negative enteric bacterium that causes nosocomial infections; this bacterium has survived from harsh condition using biofilm formation in hospital equipment and cause severe infection. In the other hand, the emergence and extension of carbapenem resistance burden among K. pneumonia producing biofilm is the current concern of public health services. There are controversial findings about this subject. The aim of this study was to evaluate the correlation between biofilm formation and resistance to carbapenem among clinical isolates of K. pneumoniae.

METHODS: A total of 160 K. pneumoniae isolates were collected from various infections of hospitalized patients. The Carba NP test and molecular methods were used for detection of carbapenem resistance isolates of K. pneumonia. Subsequently, the ability for biofilm production was performed from all isolates. Finally, Correlation of biofilm formation among carbapenem resistant isolates was calculated using χ2 and Fisher's exact tests.

RESULTS: Among K. pneumoniae isolates 42.5% have carbapenemase activity by Carba NP test, while carbapenemase genes were detected in 35.6% of isolates in amplification assay. Moreover, there are 52.5% (n= 84) of all isolates were formed a strong biofilm, while 38.1% (n= 61) and 9.3% (n= 15) of isolates were middle and weak biofilm producer, respectively. Among carbapenem resistant cases (n= 68), there are 77.9% (n= 53) and 22% (n= 15) of isolates were reported as strong and middle biofilm producer, respectively. We see a significant correlation was seen between biofilm formation ability and carbapenem resistant isolates (p-value < 0.00001).

CONCLUSION: The increase of carbapenem resistance burden in biofilm producing isolates of K. pneumoniae is considered as serious alert and the basic measures to combat this phenomenon is imperative.}, } @article {pmid31741422, year = {2020}, author = {Liu, Y and Feng, H and Chen, L and Zhang, H and Dong, X and Xiong, Q and Zhang, R}, title = {Root-Secreted Spermine Binds to Bacillus amyloliquefaciens SQR9 Histidine Kinase KinD and Modulates Biofilm Formation.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {33}, number = {3}, pages = {423-432}, doi = {10.1094/MPMI-07-19-0201-R}, pmid = {31741422}, issn = {0894-0282}, mesh = {Bacillus amyloliquefaciens/*enzymology/growth & development ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Cucumis sativus/microbiology ; Histidine Kinase/*metabolism ; Plant Exudates/chemistry ; Plant Roots/*chemistry/microbiology ; Spermine/*chemistry ; }, abstract = {The signal molecules in root exudates that are sensed by plant growth-promoting rhizobacteria (PGPR) are critical to regulate their root colonization. Phosphorylated Spo0A is an important global transcriptional regulator that controls colonization and sporulation in Bacillus species. In this study, we found that deletion of kinD from PGPR strain Bacillus amyloliquefaciens SQR9, encoding an original phosphate donor of Spo0A, resulted in reduced biofilm formation in root exudates compared with the wild-type strain, indicating that KinD is responsible for sensing root exudates. Ligands of B. amyloliquefaciens SQR9 KinD in cucumber root exudates were determined by both the nontargeted ligand fishing method and the targeted surface plasmon resonance detection method. In total, we screened 80 compounds in root exudates for binding to KinD and found that spermine and guanosine could bind to KinD with dissociation constant values of 213 and 51 μΜ, respectively. In addition, calcium l-threonate, N-acetyl-l-aspartic acid, sodium decanoic acid, and parabanic acid could also bind weakly to KinD. The three-dimensional binding models were then constructed to demonstrate the interactions between the root-secreted signals and KinD. It was observed that exogenous spermine reduced the wrinkles of biofilm when kinD was deleted, indicating that KinD might be involved in sensing root-secreted spermine and stabilizing biofilm in response to this negative effector. This study provided a new insight of interaction between a rhizobacterial sensor and root-secreted signals.}, } @article {pmid31740326, year = {2020}, author = {Fernández-Calderón, MC and Romero-Guzmán, D and Ferrández-Montero, A and Pérez-Giraldo, C and González-Carrasco, JL and Lieblich, M and Benavente, R and Ferrari, B and González-Martín, ML and Gallardo-Moreno, AM}, title = {Impact of PLA/Mg films degradation on surface physical properties and biofilm survival.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {185}, number = {}, pages = {110617}, doi = {10.1016/j.colsurfb.2019.110617}, pmid = {31740326}, issn = {1873-4367}, mesh = {Bacteria/drug effects/ultrastructure ; Biofilms/*drug effects ; Hydrogen-Ion Concentration ; Hydrophobic and Hydrophilic Interactions ; Magnesium/*pharmacology ; Microbial Viability/*drug effects ; Optical Imaging ; Polyesters/*pharmacology ; Static Electricity ; Surface Properties ; Water/chemistry ; }, abstract = {New biocompatible and bioabsorbable materials are currently being developed for bone regeneration. These serve as scaffolding for controlled drug release and prevent bacterial infections. Films of polylactic acid (PLA) polymers that are Mg-reinforced have demonstrated they have suitable properties and bioactive behavior for promoting the osseointegration process. However little attention has been paid to studying whether the degradation process can alter the adhesive physical properties of the biodegradable film and whether this can modify the biofilm formation capacity of pathogens. Moreover, considering that the concentration of Mg and other corrosion products may not be constant during the degradation process, the question that arises is whether these changes can have negative consequences in terms of the bacterial colonization of surfaces. Bacteria are able to react differently to the same compound, depending on its concentration in the medium and can even become stronger when threatened. In this context, physical surface parameters such as hydrophobicity, surface tension and zeta potential of PLA films reinforced with 10% Mg have been determined before and after degradation, as well as the biofilm formation capacity of Staphylococcus epidermidis. The addition of Mg to the films makes them less hydrophobic and the degradation also reduces the hydrophobicity and increases the negative charge of the surface, especially over long periods of time. Early biofilm formation at 8 h is consistent with the physical properties of the films, where we can observe a reduction in the bacterial biofilm formation. However, after 24 h of incubation, the biofilm formation increases significantly on the PLA/Mg films with respect to PLA control. The explosive release of Mg ions and other corrosion products within the first hours were not enough to prevent a greater biofilm formation after this initial time. Consequently, the Mg addition to the polymer matrix had a bacteriostatic effect but not a bactericidal one. Future works should aim to optimize the design and biofunctionality of these promising bioabsorbable composites for a degradation period suitable for the intended application.}, } @article {pmid31740039, year = {2020}, author = {Pan, J and Hu, J and Liu, B and Li, J and Wang, D and Bu, C and Wang, X and Xiao, K and Liang, S and Yang, J and Hou, H}, title = {Enhanced quorum sensing of anode biofilm for better sensing linearity and recovery capability of microbial fuel cell toxicity sensor.}, journal = {Environmental research}, volume = {181}, number = {}, pages = {108906}, doi = {10.1016/j.envres.2019.108906}, pmid = {31740039}, issn = {1096-0953}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Quorum Sensing ; }, abstract = {MFC toxicity sensor has major hindrances that limit its practical application, such as the poor concentration-response relationship and inferior recovery capability after high toxicity shock. Till now, the direct influence of intrinsic properties on the performance of MFC toxicity sensor has not been well understood. Quorum sensing (QS) is a cell-to-cell communication strategy that indirectly affects the intrinsic properties of electroactive biofilms. In this work, commercially available QS autoinducers (AHLs) were applied to MFC toxicity sensor to manipulate anode biofilm for better sensing performance. The results showed that the addition of AHLs (C6-HSL, 3-OXO-C12-HSL) led to higher sensing linearity to a wider range of Pb[2+]. The voltage of MFC sensors with AHLs addition fully recovered even after 10 mg/L Cu[2+] shock, indicating an enhanced recovery capability of MFC toxicity sensor. It was found that higher live/dead cells ratio and increased exoelectrogen Geobacter abundance were responsible for the superior sensing linearity and recovery capability of MFC toxicity sensor. Our work presented a novel and effective way to advance the process of MFC toxicity sensor application from the perspective of EABs.}, } @article {pmid31739833, year = {2019}, author = {Ré, ACS and Ferreira, MP and Freitas, O and Aires, CP}, title = {Antimicrobial effect of a local release system containing metronidazole against a Porphyromonas gingivalis biofilm.}, journal = {Die Pharmazie}, volume = {74}, number = {11}, pages = {665-666}, doi = {10.1691/ph.2019.8241}, pmid = {31739833}, issn = {0031-7144}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Drug Liberation ; Metronidazole/administration & dosage/*pharmacology ; Porphyromonas gingivalis/*drug effects ; Time Factors ; }, abstract = {The aim of this study was to evaluate a semi-solid system containing metronidazole (MDZ) in presence of challenging conditions for drug release, as well its antimicrobial effect against Porphyromonas gingivalis biofilm. Biofilms grown in culture medium were exposed to a formulation containing MDZ or its vehicle. After 24, 48, and 72 h, biofilm viability were analyzed while MDZ was quantified in culture medium and buffer solution (control). MDZ formulation reduced bacterial viability when compared to control groups. The vehicle formulation also affected bacterial viability in relation to control at all periods. Culture medium impaired MDZ release compared to buffer solution at 24 h. The semi-solid system reported herein is able to release MDZ and maintain its levels at concentrations that control viability of P. gingivalis in 1- to 3-day-old biofilms.}, } @article {pmid31737922, year = {2020}, author = {Zhang, Z and Du, W and Wang, M and Li, Y and Su, S and Wu, T and Kang, Y and Shan, X and Shi, Q and Zhu, G}, title = {Contribution of the colicin receptor CirA to biofilm formation, antibotic resistance, and pathogenicity of Salmonella Enteritidis.}, journal = {Journal of basic microbiology}, volume = {60}, number = {1}, pages = {72-81}, doi = {10.1002/jobm.201900418}, pmid = {31737922}, issn = {1521-4028}, support = {C2019407070//Natural Science Foundation of Hebei Province/ ; HBCT2018130203-WSZ//Earmarked Fund for Modern Agro-Industry Technology Research System of Hebei Province/ ; 31802186//National Natural Science Foundation of China/ ; 2017M611935//China Postdoctoral Science Foundation/ ; 201602A185//Science and Technology Bureau of Qinhuangdao City/ ; 201702B001//Science and Technology Bureau of Qinhuangdao City/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/growth & development ; Caco-2 Cells ; Colicins ; Drug Resistance, Bacterial ; Humans ; Macrophages/microbiology ; Mice ; Microbial Sensitivity Tests ; Microbial Viability ; RAW 264.7 Cells ; Receptors, Cell Surface/deficiency/genetics/*metabolism ; Salmonella Infections, Animal/microbiology ; Salmonella enteritidis/drug effects/*pathogenicity/*physiology ; Virulence/*genetics ; }, abstract = {Salmonella Enteritidis is an important foodborne pathogen that can infect a wide range of animal species including human beings, resulting in great losses to commercial husbandry and human health. CirA is an outer membrane receptor involved in iron uptake and colicin1A/B-mediated competitive killing. Although iron uptake is crucial to bacterial virulence, limited literature is available about the role of CirA in infection. In the present work, we aimed to evaluate the role of CirA during S. Enteritidis infection. For this purpose, we generated a CirA-deficient mutant of the S. Enteritidis strain C50336 and examined its biological characteristics. The results showed that cirA gene inactivation caused sharply decreased biofilm formation and apparently impaired antibiotic resistance. Furthermore, the cirA gene deletion mutant showed markedly reduced adhesion and invasion to human epithelial cell line Caco-2 cells and decreased proliferation in mouse macrophage cell line RAW264.7 cells. Moreover, attenuated virulence was determined by a mouse model, with an LD50 increase of approximately 1,000-fold. These data indicated that CirA plays critical roles in the S. Enteritidis infection process.}, } @article {pmid31737611, year = {2019}, author = {Qvortrup, K and Hultqvist, LD and Nilsson, M and Jakobsen, TH and Jansen, CU and Uhd, J and Andersen, JB and Nielsen, TE and Givskov, M and Tolker-Nielsen, T}, title = {Small Molecule Anti-biofilm Agents Developed on the Basis of Mechanistic Understanding of Biofilm Formation.}, journal = {Frontiers in chemistry}, volume = {7}, number = {}, pages = {742}, pmid = {31737611}, issn = {2296-2646}, abstract = {Microbial biofilms are the cause of persistent infections associated with various medical implants and distinct body sites such as the urinary tract, lungs, and wounds. Compared with their free living counterparts, bacteria in biofilms display a highly increased resistance to immune system activities and antibiotic treatment. Therefore, biofilm infections are difficult or impossible to treat with our current armory of antibiotics. The challenges associated with biofilm infections have urged researchers to pursue a better understanding of the molecular mechanisms that are involved in the formation and dispersal of biofilms, and this has led to the identification of several steps that could be targeted in order to eradicate these challenging infections. Here we describe mechanisms that are involved in the regulation of biofilm development in Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii, and provide examples of chemical compounds that have been developed to specifically inhibit these processes. These compounds include (i) pilicides and curlicides which inhibit the initial steps of biofilm formation by E. coli; (ii) compounds that interfere with c-di-GMP signaling in P. aeruginosa and E. coli; and (iii) compounds that inhibit quorum-sensing in P. aeruginosa and A. baumannii. In cases where compound series have a defined molecular target, we focus on elucidating structure activity relationship (SAR) trends within the particular compound series.}, } @article {pmid31736897, year = {2019}, author = {Roussin, M and Rabarioelina, S and Cluzeau, L and Cayron, J and Lesterlin, C and Salcedo, SP and Bigot, S}, title = {Identification of a Contact-Dependent Growth Inhibition (CDI) System That Reduces Biofilm Formation and Host Cell Adhesion of Acinetobacter baumannii DSM30011 Strain.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2450}, pmid = {31736897}, issn = {1664-302X}, abstract = {Acinetobacter baumannii is a multidrug-resistant nosocomial opportunistic pathogen that is becoming a major health threat worldwide. In this study, we have focused on the A. baumannii DSM30011 strain, an environmental isolate that retains many virulence-associated traits. We found that its genome contains two loci encoding for contact-dependent growth inhibition (CDI) systems. These systems serve to kill or inhibit the growth of non-sibling bacteria by delivering toxins into the cytoplasm of target cells, thereby conferring the host strain a significant competitive advantage. We show that one of the two toxins functions as a DNA-damaging enzyme, capable of inducing DNA double-stranded breaks to the chromosome of Escherichia coli strain. The second toxin has unknown catalytic activity but stops the growth of E. coli without bactericidal effect. In our conditions, only one of the CDI systems was highly expressed in the A. baumannii DSM30011 strain and was found to mediate interbacterial competition. Surprisingly, the absence of this CDI system promotes adhesion of A. baumannii DSM30011 to both abiotic and biotic surfaces, a phenotype that differs from previously described CDI systems. Our results suggest that a specific regulation mediated by this A. baumannii DSM30011 CDI system may result in changes in bacterial physiology that repress host cell adhesion and biofilm formation.}, } @article {pmid31734609, year = {2020}, author = {Gani, KM and Nazir, FU and Kumari, S and Bux, F and Kazmi, AA}, title = {Role of treatment configuration in simultaneous removal of priority phthalic acid esters and nitrogen in a post anoxic integrated biofilm activated sludge system.}, journal = {The Science of the total environment}, volume = {702}, number = {}, pages = {134733}, doi = {10.1016/j.scitotenv.2019.134733}, pmid = {31734609}, issn = {1879-1026}, mesh = {Biodegradation, Environmental ; Esters ; Nitrogen ; *Phthalic Acids ; Sewage ; Waste Disposal, Fluid/*methods ; *Water Pollutants, Chemical ; }, abstract = {To develop future wastewater treatment systems, focus is to improve/investigate existing biological wastewater treatment processes for the concurrent treatment of conventional pollution parameters (essentially nitrogen) and micro pollutants. Majority of the existing biological wastewater treatment systems were not designed for the removal of micro pollutants. This study focuses on understanding the role of treatment configuration for efficient removal of nitrogen and priority phthalic acid esters (PAEs) from real municipal wastewater in an integrated biofilm activated sludge (IBAS) system. The reactor was operated in two phases: Run I, without external carbon source in anoxic reactor and Run II, a nitrogen removal process, with partial diversion of untreated wastewater in anoxic reactor. Nitrogen removal was 70 ± 12% in both operational phases, however, during Run I, removal of PAEs fluctuated with an average removal of 60-78%. Comparatively, removal of PAEs in Run II varied over a smaller range with average removal increased to 89-95%. In both operational scenarios, secondary oxic tank contributed maximum to the overall removal of PAEs in treatment system. Mass balance calculations showed significant contribution of biodegradation towards overall removal of PAEs which was enhanced by the supply of external carbon source. Kinetics and model output supported the PAEs removal performance observed in different reaction environments of IBAS process. A correlation between food to microorganism (F/M) ratio and PAEs removal showed increase in PAEs removal with decrease in F/M ratio. The study showed that treatment configuration and F/M ratio may be one of the guiding parameters for efficient removal of PAEs in biological wastewater treatment.}, } @article {pmid31734360, year = {2020}, author = {Wang, SH and Chen, CC and Lee, CH and Chen, XA and Chang, TY and Cheng, YC and Young, JJ and Lu, JJ}, title = {Fungicidal and anti-biofilm activities of trimethylchitosan-stabilized silver nanoparticles against Candida species in zebrafish embryos.}, journal = {International journal of biological macromolecules}, volume = {143}, number = {}, pages = {724-731}, doi = {10.1016/j.ijbiomac.2019.10.002}, pmid = {31734360}, issn = {1879-0003}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Cell Death/drug effects ; Cell Line ; Chitosan/*pharmacology ; Embryo, Nonmammalian/drug effects/*microbiology ; Metal Nanoparticles/*chemistry/ultrastructure ; Mice ; Microbial Sensitivity Tests ; Ovum/drug effects ; Silver/*pharmacology ; Zebrafish/embryology/*microbiology ; }, abstract = {Herein, positively surface-charged silver nanoparticles (AgNPs) capped with trimethylchitosan nitrate (TMCN) were synthesized using an environmentally friendly method. Nano-sized TMCN-AgNPs (~80 nm) with high zeta potential (>30 mV) provide sufficient static repulsion to stabilize colloid AgNPs in aqueous solutions without aggregation for >3 months. In in vitro cell cycle assays, TMCN-AgNPs showed low cytotoxicity towards L929 cells. A microdilution inhibition assay demonstrated the antifungal potential of TMCN-AgNPs, with a minimum inhibitory concentration of 0.06 mM against Candida tropicalis ATCC 750, and 0.46 mM against both Candida albicans ATCC 76615 and Candida glabrata ATCC 15545. Moreover, the addition of TMCN-AgNPs at 0.23 mM significantly reduced biofilm formation in 96-well plates with C. albicans and C. tropicalis. Importantly, when zebrafish eggs were infected with Candida cells, 0.23 mM TMCN-AgNPs greatly diminished the amount of biofilm on eggs and rescued the survival of embryos by up to 70%.}, } @article {pmid31733924, year = {2020}, author = {Barnier, C and Clerissi, C and Lami, R and Intertaglia, L and Lebaron, P and Grimaud, R and Urios, L}, title = {Description of Palleronia rufa sp. nov., a biofilm-forming and AHL-producing Rhodobacteraceae, reclassification of Hwanghaeicola aestuarii as Palleronia aestuarii comb. nov., Maribius pontilimi as Palleronia pontilimi comb. nov., Maribius salinus as Palleronia salina comb. nov., Maribius pelagius as Palleronia pelagia comb. nov. and emended description of the genus Palleronia.}, journal = {Systematic and applied microbiology}, volume = {43}, number = {1}, pages = {126018}, doi = {10.1016/j.syapm.2019.126018}, pmid = {31733924}, issn = {1618-0984}, mesh = {Acyl-Butyrolactones/*metabolism ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; Genes, Essential/genetics ; Genome, Bacterial/genetics ; New Caledonia ; Phylogeny ; Quorum Sensing ; RNA, Ribosomal, 16S/genetics ; Rhodobacteraceae/chemistry/*classification/cytology/*physiology ; Roseobacter/chemistry/classification/cytology/physiology ; Seawater/microbiology ; Sequence Analysis, DNA ; Sequence Homology, Nucleic Acid ; Species Specificity ; }, abstract = {Strain MOLA 401[T] was isolated from marine waters in the southwest lagoon of New Caledonia and was shown previously to produce an unusual diversity of quorum sensing signaling molecules. This strain was Gram-negative, formed non-motile cocci and colonies were caramel. Optimum growth conditions were 30°C, pH 8 and 3% NaCl (w/v). Based on 16S rRNA gene sequence analysis, this strain was found to be closely related to Pseudomaribius aestuariivivens NBRC 113039[T] (96.9% of similarity), Maribius pontilimi DSM 104950[T] (96.4% of similarity) and Palleronia marisminoris LMG 22959[T] (96.3% of similarity), belonging to the Roseobacter group within the family Rhodobacteraceae. As its closest relatives, strain MOLA 401[T] is able to form a biofilm on polystyrene, supporting the view of Roseobacter group strains as prolific surface colonizers. An in-depth genomic study allowed us to affiliate strain MOLA 401[T] as a new species of genus Palleronia and to reaffiliate some of its closest relatives in this genus. Consequently, we describe strain MOLA 401[T] (DSM 106827[T]=CIP 111607[T]=BBCC 401[T]) for which we propose the name Palleronia rufa sp. nov. We also propose to emend the description of the genus Palleronia and to reclassify Maribius and Hwanghaeicola species as Palleronia species.}, } @article {pmid31732413, year = {2020}, author = {Sun, Z and Ding, C and Xi, J and Lu, L and Yang, B}, title = {Enhancing biofilm formation in biofilters for benzene, toluene, ethylbenzene, and xylene removal by modifying the packing material surface.}, journal = {Bioresource technology}, volume = {296}, number = {}, pages = {122335}, doi = {10.1016/j.biortech.2019.122335}, pmid = {31732413}, issn = {1873-2976}, mesh = {Benzene ; Benzene Derivatives ; Biodegradation, Environmental ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Toluene ; *Xylenes ; }, abstract = {Polyurethane (PU) sponges are popular packing material in biofilters and their smooth and hydrophobic surface often leads to an uneven distribution and detachment of biofilms. In this work, the surface of PU sponge was modified to obtain higher roughness and positive charge. The performances of two biofilters (BF1 with pristine sponge and BF2 with modified sponge) for benzene, toluene, ethylbenzene, and xylene (BTEX) removal were investigated. Total Volatile Organic Compound (TVOC) removal efficiency and CO2 increment were 61% and 804 ppm for BF2 respectively after start-up, compared with 51% and 538 ppm for BF1. Analysis on biofilms showed that the modification of PU sponge significantly improved the microbial growth, viability and adhesive strength in biofilms, reduced extracellular polymeric substance (EPS) and changed the microbial community. These results demonstrate that modified sponge can enhance biofilm formation and BTEX removal in biofilters and may applied in large-scale applications.}, } @article {pmid31731396, year = {2019}, author = {Choi, HW and Park, SY and Kang, MK and Shon, WJ}, title = {Comparative Analysis of Biofilm Removal Efficacy by Multisonic Ultracleaning System and Passive Ultrasonic Activation.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {21}, pages = {}, pmid = {31731396}, issn = {1996-1944}, support = {H18C1234//Korean Health Technology R&D Project KHIDI/ ; 01-2016-0008//Seoul National University Dental Hospital/ ; }, abstract = {The purpose of this study was to compare disinfection and the biofilm removal efficacy of the GentleWave System (Sonendo, Inc., Laguna Hills, CA, USA) with passive ultrasonic activation method. Forty-seven freshly extracted human molars were inoculated with Enterococcus faecalis and cultured for five weeks to establish biofilm. Eight molars were tested for confirmation of infection. Four of the eight teeth were not inoculated in order to provide a negative control. The remaining 39 inoculated molars were randomly separated into three treatment groups (n = 13 per group): Group 1-no treatment, Group 2-conventional rotary instrumentation and passive ultrasonic activation, and Group 3-minimal instrumentation and the GentleWave System treatment. Roots were subsequently prepared per standard histological tissue processing procedures. Modified Brown and Brenn stained sections and Hematoxylin and Eosin stained sections were visualized at 4× and 13.5× magnification using a stereomicroscope. The sections were scored and blindly analyzed by two independent evaluators, including a histopathologist, to evaluate the presence of biofilm on canal wall. A significant difference was found between Group 2 and Group 3 in both apical and middle regions (p = 0.001) of the mesial roots of mandibular molars and mesiobuccal roots of maxillary molars. Group 3 revealed significantly less biofilm than the controls (p = 0.003). The GentleWave System demonstrated significantly greater reduction in biofilm within the mesial roots of mandibular molars and mesiobuccal roots of maxillary molars than those treated with conventional rotary instrumentation and passive ultrasonic activation protocol.}, } @article {pmid31728266, year = {2019}, author = {Azimi, L and Lari, AR}, title = {Colistin-resistant Pseudomonas aeruginosa clinical strains with defective biofilm formation.}, journal = {GMS hygiene and infection control}, volume = {14}, number = {}, pages = {Doc12}, pmid = {31728266}, issn = {2196-5226}, abstract = {Aim: Colistin is the only effective antibiotic in some cases of Pseudo monas aeruginosa resistance to all tested antibiotics, even carbapenem. On the other hand, biofilm formation is one of the antibiotic resistance mechanisms in this bacterium. The aim of this study was to examine biofilm formation in colistin-resistant P. aeruginosa for the first time. Method: Two groups of P. aeruginosa were included in this study: 1) colistin-resistant and 2) colistin-susceptible. Biofilm formation was determined in these groups using the micro-tube test well as PCR to detect the genes involved in biofilm formation (ppk and molA). The plasmids for colistin resistance, mcr-1 and mcr-2, were also determined. P. aeruginosa ATCC 27853 was used as a control for all tests. Results: Strong biofilm formation was observed only in colistin-susceptible strains, and ppk and modA were not detected in colistin-resistant strains. The control strain P. aeruginosa ATCC 27853 possesses ppk and modA and is categorized as a strong biofilm formation group. According to the results of this study, colistin resistance is associated with defective biofilm formation, as reported by other studies on Acinetobacter baumannii.}, } @article {pmid31728201, year = {2019}, author = {Penesyan, A and Nagy, SS and Kjelleberg, S and Gillings, MR and Paulsen, IT}, title = {Rapid microevolution of biofilm cells in response to antibiotics.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {34}, pmid = {31728201}, issn = {2055-5008}, mesh = {Acinetobacter baumannii/*drug effects/*growth & development ; Anti-Bacterial Agents/*metabolism ; Biofilms/*drug effects/*growth & development ; *Drug Resistance ; Drug Tolerance ; Gene Expression Profiling ; Whole Genome Sequencing ; }, abstract = {Infections caused by Acinetobacter baumannii are increasingly antibiotic resistant, generating a significant public health problem. Like many bacteria, A. baumannii adopts a biofilm lifestyle that enhances its antibiotic resistance and environmental resilience. Biofilms represent the predominant mode of microbial life, but research into antibiotic resistance has mainly focused on planktonic cells. We investigated the dynamics of A. baumannii biofilms in the presence of antibiotics. A 3-day exposure of A. baumannii biofilms to sub-inhibitory concentrations of antibiotics had a profound effect, increasing biofilm formation and antibiotic resistance in the majority of biofilm dispersal isolates. Cells dispersing from biofilms were genome sequenced to identify mutations accumulating in their genomes, and network analysis linked these mutations to their phenotypes. Transcriptomics of biofilms confirmed the network analysis results, revealing novel gene functions of relevance to both resistance and biofilm formation. This approach is a rapid and objective tool for investigating resistance dynamics of biofilms.}, } @article {pmid31727369, year = {2020}, author = {Katoch, P and Gupta, K and Yennamalli, RM and Vashistt, J and Bisht, GS and Shrivastava, R}, title = {Random insertion transposon mutagenesis of Mycobacterium fortuitum identified mutant defective in biofilm formation.}, journal = {Biochemical and biophysical research communications}, volume = {521}, number = {4}, pages = {991-996}, doi = {10.1016/j.bbrc.2019.11.021}, pmid = {31727369}, issn = {1090-2104}, mesh = {Anthranilate Phosphoribosyltransferase/chemistry/metabolism ; Bacterial Proteins/chemistry/metabolism ; Biofilms/*growth & development ; Chorismic Acid/metabolism ; DNA Transposable Elements/*genetics ; Mutagenesis, Insertional/*genetics ; Mutation/*genetics ; Mycobacterium fortuitum/*genetics/*physiology ; Protein Interaction Mapping ; Protein Structure, Secondary ; }, abstract = {Mycobacterium fortuitum has emerged as a nosocomial infectious agent and biofilm formation attributed for the presence of this bacterium in hospital environment. Transposon random mutagenesis was used to identify membrane-proteins for biofilm formation in M. fortuitum. Ten mutants were shortlisted from a library of 450 mutants for examine their biofilm forming ability. Comparative biofilm ability with respect to wild type M. fortuitum ATCC 6841 showed an altered and delayed biofilm formation in one mutant namely, MT721. Sequence analysis revealed mutation in anthranilate phosphoribosyl transferase (MftrpD), which is associated with tryptophan operon. Functional interaction study of TrpD protein through STRING showed its interaction with chorismate utilizing proteins, majorly involved in synthesis of aromatic amino acid and folic acid, suggesting that biofilm establishment and maintenance requires components of central metabolism. Our study indicates important role of MftrpD in establishment and maintenance of biofilm by M. fortuitum, which may further be explored for drug discovery studies against mycobacterial infections.}, } @article {pmid31725203, year = {2020}, author = {Bernardi, S and Karygianni, L and Filippi, A and Anderson, AC and Zürcher, A and Hellwig, E and Vach, K and Macchiarelli, G and Al-Ahmad, A}, title = {Combining culture and culture-independent methods reveals new microbial composition of halitosis patients' tongue biofilm.}, journal = {MicrobiologyOpen}, volume = {9}, number = {2}, pages = {e958}, pmid = {31725203}, issn = {2045-8827}, mesh = {Adult ; Aged ; Bacterial Typing Techniques ; Biodiversity ; Biofilms/*growth & development ; Female ; Halitosis/*diagnosis/drug therapy/*microbiology ; Humans ; Male ; Microbiological Techniques ; *Microbiota ; Middle Aged ; Mouth/microbiology ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S/genetics ; Tongue/*microbiology ; Young Adult ; }, abstract = {BACKGROUND: Oral malodor is a very discomforting condition deriving from the presence of volatile sulfur compounds in the expired air. In halitosis of intraoral etiology, the volatile sulfur compounds are metabolic products of the oral microorganisms within the biofilm coating the tongue dorsum as well as other tissues in the oral cavity. The aim of this study was to characterize and compare the microbial composition of tongue biofilm in volunteers suffering from halitosis and healthy volunteers by means of both the culture method and culture-independent cloning technique.

RESULTS: A high bacterial variety (more than 80 different species) was detected using the combination of both methods. A distinct bacterial composition was revealed in the halitosis-associated biofilms compared with the health-associated biofilms. Actinomyces graevenitzii was shown to be significantly associated with the halitosis condition. The culture method identified 47 species, included Veillonella rogosae, never isolated from the tongue biofilm of halitosis patients so far. In the healthy condition, the culture-dependent method showed that the most frequent species were Streptococcus parasanguinis among the aerobes and Veillonella spp. among the anaerobes. The culture-independent cloning method detected more than 50 species. Streptococci, in particular S. mitis/oralis, S. pseudopneumoniae, and S. infantis as well as Prevotella spp., were found most frequently in halitosis patients. Streptococcus salivarius and Rothia mucilaginosa were found more frequently in the healthy condition.

CONCLUSIONS: The combination of the culture-dependent and culture-independent cloning techniques allowed for a widespread analysis of the tongue biofilm in halitosis patients. The results can support further pharmacological research for new antimicrobial agents and halitosis therapy strategies.}, } @article {pmid31722994, year = {2019}, author = {Oppy, CC and Jebeli, L and Kuba, M and Oates, CV and Strugnell, R and Edgington-Mitchell, LE and Valvano, MA and Hartland, EL and Newton, HJ and Scott, NE}, title = {Loss of O-Linked Protein Glycosylation in Burkholderia cenocepacia Impairs Biofilm Formation and Siderophore Activity and Alters Transcriptional Regulators.}, journal = {mSphere}, volume = {4}, number = {6}, pages = {}, pmid = {31722994}, issn = {2379-5042}, support = {MC_PC_17175/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Biofilms/*growth & development ; Burkholderia cenocepacia/*growth & development/*metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genes, Reporter ; *Glycosylation ; Proteomics ; Siderophores/*metabolism ; Transcription Factors/*metabolism ; }, abstract = {O-linked protein glycosylation is a conserved feature of the Burkholderia genus. The addition of the trisaccharide β-Gal-(1,3)-α-GalNAc-(1,3)-β-GalNAc to membrane exported proteins in Burkholderia cenocepacia is required for bacterial fitness and resistance to environmental stress. However, the underlying causes of the defects observed in the absence of glycosylation are unclear. Using proteomics, luciferase reporter assays, and DNA cross-linking, we demonstrate the loss of glycosylation leads to changes in transcriptional regulation of multiple proteins, including the repression of the master quorum CepR/I. These proteomic and transcriptional alterations lead to the abolition of biofilm formation and defects in siderophore activity. Surprisingly, the abundance of most of the known glycosylated proteins did not significantly change in the glycosylation-defective mutants, except for BCAL1086 and BCAL2974, which were found in reduced amounts, suggesting they could be degraded. However, the loss of these two proteins was not responsible for driving the proteomic alterations, biofilm formation, or siderophore activity. Together, our results show that loss of glycosylation in B. cenocepacia results in a global cell reprogramming via alteration of the transcriptional regulatory systems, which cannot be explained by the abundance changes in known B. cenocepacia glycoproteins.IMPORTANCE Protein glycosylation is increasingly recognized as a common posttranslational protein modification in bacterial species. Despite this commonality, our understanding of the role of most glycosylation systems in bacterial physiology and pathogenesis is incomplete. In this work, we investigated the effect of the disruption of O-linked glycosylation in the opportunistic pathogen Burkholderia cenocepacia using a combination of proteomic, molecular, and phenotypic assays. We find that in contrast to recent findings on the N-linked glycosylation systems of Campylobacter jejuni, O-linked glycosylation does not appear to play a role in proteome stabilization of most glycoproteins. Our results reveal that loss of glycosylation in B. cenocepacia strains leads to global proteome and transcriptional changes, including the repression of the quorum-sensing regulator cepR (BCAM1868) gene. These alterations lead to dramatic phenotypic changes in glycosylation-null strains, which are paralleled by both global proteomic and transcriptional alterations, which do not appear to directly result from the loss of glycosylation per se. This research unravels the pleiotropic effects of O-linked glycosylation in B. cenocepacia, demonstrating that its loss does not simply affect the stability of the glycoproteome, but also interferes with transcription and the broader proteome.}, } @article {pmid31721708, year = {2020}, author = {Khan, F and Pham, DTN and Oloketuyi, SF and Kim, YM}, title = {Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria.}, journal = {Current pharmaceutical biotechnology}, volume = {21}, number = {4}, pages = {270-286}, doi = {10.2174/1389201020666191112155905}, pmid = {31721708}, issn = {1873-4316}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/drug effects/genetics ; Humans ; Listeria monocytogenes/*drug effects/genetics/pathogenicity ; Microbial Sensitivity Tests ; Quorum Sensing/*drug effects/genetics ; Staphylococcus aureus/*drug effects/genetics/pathogenicity ; Virulence Factors/genetics/metabolism ; }, abstract = {BACKGROUND: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment.

METHODS: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm.

RESULTS: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier.

CONCLUSION: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.}, } @article {pmid31721122, year = {2020}, author = {Van Dyck, K and Van Dijck, P and Vande Velde, G}, title = {Bioluminescence Imaging to Study Mature Biofilm Formation by Candida spp. and Antifungal Activity In Vitro and In Vivo.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {2081}, number = {}, pages = {127-143}, doi = {10.1007/978-1-4939-9940-8_9}, pmid = {31721122}, issn = {1940-6029}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/genetics/metabolism ; Candidiasis/drug therapy/*microbiology ; Female ; Gene Expression ; Genes, Reporter ; Luminescent Measurements/*methods ; Mice ; Optical Imaging/*methods ; Rats ; }, abstract = {The widespread use of indwelling medical devices has increased the number of device-related infections in hospitalized patients. These infections are often associated with the formation of biofilms on the medical implants that are difficult to treat because of their resistance to the classical antifungal drugs. The most common fungi isolated from catheters and other medical devices are Candida species. The Candida genus contains multiple species of which C. albicans and C. glabrata are the two most common pathogenic yeasts in humans. A limited number of animal models is available for investigating host-pathogen interactions and testing novel antifungal drugs in vivo against these species. Fungal load in biofilms in these models is traditionally analyzed postmortem, requiring host sacrifice and enumeration of microorganisms from individual biofilms in order to evaluate the amount of colony forming units and the efficacy of antifungal treatment. Bioluminescence imaging (BLI) made compatible with small animal models for in vivo biofilm formation is a valuable tool to follow biofilm development and its treatment longitudinally. Due to the noninvasive nature of BLI, the imaging procedure can be repeated in the same animal, allowing for follow-up of the biofilm growth in vivo without removing the implanted device or detaching the biofilm from its substrate. Although detecting a quantifiable in vivo BLI signal from biofilms formed on the inside of implanted catheters is challenging, BLI proved to be a practical tool in the study of fungal biofilms. This method describes the use of BLI for in vitro and in vivo follow-up of device-related fungal biofilm formation in mice and rats and antifungal activity testing against both C. albicans and C. glabrata device-associated biofilms. It can further be applied for efficient in vivo screening for interesting genes of the pathogen and the host involved in biofilm formation.}, } @article {pmid31720769, year = {2020}, author = {Zhang, Y and Zhao, L and Song, T and Cheng, Y and Bao, M and Li, Y}, title = {Simultaneous nitrification and denitrification in an aerobic biofilm biosystem with loofah sponges as carriers for biodegrading hydrolyzed polyacrylamide-containing wastewater.}, journal = {Bioprocess and biosystems engineering}, volume = {43}, number = {3}, pages = {529-540}, doi = {10.1007/s00449-019-02247-x}, pmid = {31720769}, issn = {1615-7605}, support = {2013AA064401//Major Projects of the National High Technology Research and Development Program 863/ ; 51174181//National Natural Science Foundation of China/ ; 201861016//Fundamental Research Funds for the Central Universities/ ; 2017GSF217012//Key Research and Development Program of Shandong Province (public welfare special project)/ ; }, mesh = {Acrylic Resins/*chemistry ; Aerobiosis ; Bacteria/*metabolism ; *Biofilms ; Bioreactors ; Biotransformation ; Hydrolysis ; *Luffa ; *Nitrification ; *Wastewater ; }, abstract = {Simultaneous nitrification and denitrification (SND) during treating hydrolyzed polyacrylamide (HPAM) containing wastewater were explored in an aerobic biofilm reactor biosystem. Here, loofah sponges as the environment-friendly and low-cost material were applied as the carriers in this biosystem. The removal efficiencies of HPAM and total nitrogen (TN) reached 43.6% and 54.3%, respectively, after 120 days stabilized running periods. Moreover, the structure of loofah sponges affected anaerobic microenvironment significantly which was indispensable for realizing a high-performance of SND. Key microorganisms in this biosystem included nitrobacteria, denitrobacteria and HPAM-biodegrading bacteria. The abundance of nitrobacteria and denitrobacteria on the biofilm was increased by 17.2% and 15.3%, respectively, through cultivation. Meanwhile, the biotransformation mechanisms of HPAM and diverse valence of nitrogen under different chemical oxygen demand (COD)/N and dissolved oxygen (DO) conditions were investigated. When COD/N and DO were 8:1 and 2 mg/L, HPAM biodegradation, SND efficiency and TN removal achieved their maximum, and the values were 54.3%, 92.3% and 60.1%, respectively. Key enzyme activities also reached their maximum in this condition. The optimal COD/N and DO was pivotal to achieve the high-performance of SND, and it was closely correlated with HPAM biodegradation. Meanwhile, SND could facilitate the biotransformation of HPAM.}, } @article {pmid31719975, year = {2019}, author = {Ranjbar, R and Farahani, A}, title = {Study of genetic diversity, biofilm formation, and detection of Carbapenemase, MBL, ESBL, and tetracycline resistance genes in multidrug-resistant Acinetobacter baumannii isolated from burn wound infections in Iran.}, journal = {Antimicrobial resistance and infection control}, volume = {8}, number = {}, pages = {172}, pmid = {31719975}, issn = {2047-2994}, mesh = {Acinetobacter Infections/diagnosis/*epidemiology/*etiology ; Acinetobacter baumannii/classification/*drug effects/*genetics/isolation & purification ; Adolescent ; Adult ; Aged ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; *Biofilms ; Burns/*complications ; Child ; Child, Preschool ; Cross-Sectional Studies ; *Drug Resistance, Multiple, Bacterial ; *Genetic Variation ; Geography, Medical ; Humans ; Infant ; Infant, Newborn ; Iran/epidemiology ; Microbial Sensitivity Tests ; Middle Aged ; Public Health Surveillance ; Tetracycline Resistance ; Young Adult ; beta-Lactamases/genetics ; }, abstract = {BACKGROUND: Antimicrobial resistance in multidrug-resistant Acinetobacter baumannii (MDR-AB) isolated from burn wound infections is a major concern in intensive care or burns units worldwide, and molecular studies are considered critical strategies for control of MDR-AB outbreaks in this regard. Thus, in this study, antibiotic resistance, biofilm-forming ability, molecular epidemiology of MDR A. baumannii strains recovered from patients with burns were investigated in three major hospital centers of Iran.

METHODS: In this cross-sectional research, 163 non-repetitive A. baumannii strains were tested for susceptibility to antimicrobial agents. Polymerase chain reaction (PCR) was performed to characterize ambler classes A, B, and D β-lactamases, ISAba1 and integrons, biofilm formation was also investigated. Clonal relatedness was analyzed using Pulsed-Field Gel Electrophoresis (PFGE).

RESULTS: Among 163 A. baumannii strains collected, 94.5% of them were Carbapenem-Non-Susceptible A. baumannii (CNSAB) and also 90.1 and 52.2% of them were Metallo-β-Lactamases (MBL) and Extended-Spectrum β-Lactamases (ESBL) producing isolates, respectively. Colistin and polymyxin B exhibited excellent activity against CNSAB strains. High prevalence of blaOXA - 23-like (85.1%), blaVIM (60.5%), blaPER - 1 (42.3%), tetB (67.8%), and Class 1 integrons (65.6%) were identified in CNSAB strains. ISAba1 element was associated with 42 (25.8%) and 129 (98.5%) of blaOXA-51-like and blaOXA-23-like genes, respectively. 6 clusters with the ability to form strong biofilms were found to be dominant and endemic in our entire areas.

CONCLUSIONS: Results of the present study show that antimicrobial resistance in CNSAB isolates from burn wound infections in monitored hospitals in Iran is multifactorial, and also findings of the study suggested that local antibiotic prescription policies should be regularly reviewed, and efficient infection control measures should be observed. Therefore, further strengthening of surveillance of antimicrobial resistance is urgently needed in these regions.}, } @article {pmid31719559, year = {2019}, author = {Horváth, B and Balázs, VL and Varga, A and Böszörményi, A and Kocsis, B and Horváth, G and Széchenyi, A}, title = {Preparation, characterisation and microbiological examination of Pickering nano-emulsions containing essential oils, and their effect on Streptococcus mutans biofilm treatment.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {16611}, pmid = {31719559}, issn = {2045-2322}, mesh = {Biofilms/*drug effects ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Nanoparticles/ultrastructure ; Oils, Volatile/administration & dosage/*pharmacology ; Silicon Dioxide/administration & dosage/pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {Essential oils (EOs) are commonly applied in mouth care products like mouthwashes, mostly as an ethanolic solution or by usage of surfactants as solubilising agents. In this study, we present a formulation for preparation of Pickering nano-emulsions (PnE) of EOs as a novel form for application of EOs in mouth care. For the preparation of PnE, we have synthesised surface-modified silica nanoparticles with a mean diameter of 20 nm, as well as we have examined the effect of EOs concentration on PnE droplet size and stability. In vitro study of their effect on the Streptococcus mutans biofilm as the main pathogen of dental health problems has been performed. We have found that EOs in the PnE form has the highest effectiveness against biofilm formation. Diffusion through the biofilm model membrane was studied to explain this observation. We have found that PnEs have a better performance in the transportation of EOs trough model membrane than the ethanolic solutions and conventional emulsions (CEs).}, } @article {pmid31719234, year = {2019}, author = {Vaishampayan, A and Grohmann, E}, title = {Multi-resistant biofilm-forming pathogens on the International Space Station.}, journal = {Journal of biosciences}, volume = {44}, number = {5}, pages = {}, pmid = {31719234}, issn = {0973-7138}, mesh = {Archaea/isolation & purification/*pathogenicity ; Bacteria/isolation & purification/*pathogenicity ; *Biofilms ; *Spacecraft ; Species Specificity ; }, abstract = {The International Space Station (ISS) is a confined and closed habitat with unique conditions such as cosmic radiation, and microgravity. These conditions have a strong effect on the human and spacecraft microflora. They can affect the immune response of the crew-members, thus posing a threat to their health. Microbial diversity and abundance of microorganisms from surfaces, air filters and air samples on the ISS have been studied. Enterobacteriaceae, Bacillus spp., Propionibacterium spp., Corynebacterium spp., and Staphylococcus spp. were among the most frequently isolated bacteria. Microbial growth, biofilm formation, stress response, and pathogenicity are affected by microgravity. Increased resistance to antibiotics in bacteria isolated from the ISS has often been reported. Enterococcus faecalis and Staphylococcus spp. isolates from the ISS have been shown to harbor plasmid-encoded transfer genes. These genes facilitate the dissemination of antibiotic resistances. These features of ISS-pathogens call for novel approaches including highly effective antimicrobials which can be easily used on the ISS. A promising material is the antimicrobial surface coating AGXX, a self-recycling material consisting of two noble metals. It drastically reduced microbial growth of multi-resistant human pathogens, such as staphylococci and enterococci. Further novel approaches include the application of cold atmospheric plasma for the sterilization of spacecrafts.}, } @article {pmid31719231, year = {2019}, author = {Manobala, T and Shukla, SK and Rao, TS and Kumar, MD}, title = {A new uranium bioremediation approach using radio-tolerant Deinococcus radiodurans biofilm.}, journal = {Journal of biosciences}, volume = {44}, number = {5}, pages = {}, pmid = {31719231}, issn = {0973-7138}, mesh = {Adsorption ; *Biodegradation, Environmental ; Biofilms/growth & development ; Deinococcus/growth & development/*radiation effects/ultrastructure ; Microscopy, Electron, Scanning ; *Radiation Tolerance ; Uranium/*toxicity ; }, abstract = {Deinococcus radiodurans is the most radiation-tolerant organism ever known. It has gained importance in recent years as a potential candidate for bioremediation of heavy metals, especially the radioactive type. This study investigates the efficiency of a recombinant D. radiodurans (DR1-bf[+]) strain with an ability to form biofilm for uranium remediation. The modified Arsenazo III dye method was used to estimate the uranium concentration. Uranyl nitrate aqueous solution was generated during the operation of nuclear fuel reprocessing. The D. radiodurans biofilm (DR1-bf[+]) grown in the presence of 20 mM Ca[2+] showed remarkable ability of uranyl ion removal. DR1-bf[+] (Ca[2+]) biofilm removed ~75+/-2% of 1000 mg/L uranium within 30 min post-treatment from uranyl nitrate aqueous solution. Uranium removal rate was also found to be directly proportional to biofilm age. This study discusses the ability of D. radiodurans biofilm in uranium removal.}, } @article {pmid31719217, year = {2019}, author = {Karley, D and Shukla, SK and Rao, TS}, title = {Microbiota of spent nuclear fuel pool water with emphasis on their biofilm forming ability on stainless steel (SS-304L).}, journal = {Journal of biosciences}, volume = {44}, number = {5}, pages = {}, pmid = {31719217}, issn = {0973-7138}, mesh = {Bacteria/genetics/isolation & purification/metabolism ; *Biofilms ; *Microbiota ; *Nuclear Reactors ; RNA, Ribosomal, 16S/genetics ; *Radioactive Waste ; *Stainless Steel ; *Water Microbiology ; }, abstract = {Spent nuclear fuel (SNF) pool is an essential unit of a nuclear power plant infrastructure, where radioactive fuel rods are kept for cooling and shielding, before reprocessing. This study explored the presence of bacteria in SNF pool water with emphasis on their capability to form biofilms on pool wall cladding material stainless steel (SS-304L). Bacteria were isolated from SNF pool water and were characterized using 16S rRNA gene sequencing. The six bacterial isolates (Bacillus subtilis, Staphylococcus sps., S. arlettae, S. epidermidis, S. auricularis and Chryseobacterium gleum) can grow and form biofilms at very low nutrient condition as well as in chronic radioactivity. The bacterial isolates formed biofilm on SS-304L and glass. However, the biofilm parameters assessed by CLSM microscopy showed that the strains preferred SS-304L surface for biofilm formation. On SS-304L, the maximum biomass (0.45 l μm[3]/l μm[2]) was formed by S. arlettae when compared to maximum biomass (0.054 l μm[3]/l μm2) by Staphylococcus sp., on glass. Maximum biofilm thickness on SS- 304L was observed by Staphylococcus sp. (8.81 l μm) when compared to that of S. epidermidis (4.16 l μm) on the glass surface. The biofilm formation on SS-304L surface suggests the possible risk of microbial-induced corrosion of SNF pool cladding material. This study highlights the need for mandatory monitoring of microbial biofilm formation in an extreme environment such as SNF pool.}, } @article {pmid31718302, year = {2019}, author = {Padmavathi, AR and Sriyutha Murthy, P and Das, A and Nishad, PA and Pandian, R and Rao, TS}, title = {Copper oxide nanoparticles as an effective anti-biofilm agent against a copper tolerant marine bacterium, Staphylococcus lentus.}, journal = {Biofouling}, volume = {35}, number = {9}, pages = {1007-1025}, doi = {10.1080/08927014.2019.1687689}, pmid = {31718302}, issn = {1029-2454}, mesh = {Adaptation, Physiological/*drug effects ; Biofilms/*drug effects ; Copper/chemistry/*pharmacology ; Disinfectants/chemistry/*pharmacology ; India ; Nanoparticles/*chemistry ; Seawater/microbiology ; Staphylococcus/*drug effects ; }, abstract = {Biofilm formation on antifouling coatings is a serious concern in seawater cooling systems and the maritime industry. A prolific biofilm forming strain (Staphylococcus lentus), possessing high tolerance (>1,000 µg ml[-1]) to dissolved copper ions (Cu[++]) was isolated from titanium coupons exposed in the coastal waters of Kalpakkam, east coast of India. S. lentus formed increased biofilm (p < 0.05) at 100 µg ml[-1] of Cu[++] ions, when compared with the untreated control. To combat biofilm formation of this strain, the efficacy of copper oxide nanoparticles synthesized from copper nitrate by varying the concentrations of hexamine and cetyl trimethyl ammonium bromide (CTAB), was investigated. Complete (100%) inhibition of biofilm formation was observed with plain CuO NP (0.5 M hexamine, uncapped) at 1,000 µg ml[-1]. Capping with CTAB, influenced the morphology and the purity of the synthesized CuO NPs but did not alter their surface charge. Capping reduced metal ion release from CuO NPs and their antibacterial and anti-biofilm property against S. lentus. Overall, uncapped CuO NPs were effective in controlling biofilm formation of S. lentus. Concurrent release of copper ions and contact mediated physical damage by CuO NPs offer a promising approach to tackle metal tolerant biofilm bacteria.}, } @article {pmid31717821, year = {2019}, author = {Najarzadeh, Z and Mohammad-Beigi, H and Nedergaard Pedersen, J and Christiansen, G and Sønderby, TV and Shojaosadati, SA and Morshedi, D and Strømgaard, K and Meisl, G and Sutherland, D and Skov Pedersen, J and Otzen, DE}, title = {Plant Polyphenols Inhibit Functional Amyloid and Biofilm Formation in Pseudomonas Strains by Directing Monomers to Off-Pathway Oligomers.}, journal = {Biomolecules}, volume = {9}, number = {11}, pages = {}, pmid = {31717821}, issn = {2218-273X}, mesh = {Amyloid/genetics/*metabolism ; Biofilms/drug effects ; Catechin/*analogs & derivatives/pharmacology ; Fungal Proteins/genetics/*metabolism ; Hydrolyzable Tannins/*pharmacology ; Polyphenols/*pharmacology ; Protein Aggregates/drug effects ; Pseudomonas/*drug effects/physiology ; }, abstract = {Self-assembly of proteins to β-sheet rich amyloid fibrils is commonly observed in various neurodegenerative diseases. However, amyloid also occurs in the extracellular matrix of bacterial biofilm, which protects bacteria from environmental stress and antibiotics. Many Pseudomonas strains produce functional amyloid where the main component is the highly fibrillation-prone protein FapC. FapC fibrillation may be inhibited by small molecules such as plant polyphenols, which are already known to inhibit formation of pathogenic amyloid, but the mechanism and biological impact of inhibition is unclear. Here, we elucidate how polyphenols modify the self-assembly of functional amyloid, with particular focus on epigallocatechin gallate (EGCG), penta-O-galloyl-β-d-glucose (PGG), baicalein, oleuropein, and procyanidin B2. We find EGCG and PGG to be the best inhibitors. These compounds inhibit amyloid formation by redirecting the aggregation of FapC monomers into oligomeric species, which according to small-angle X-ray scattering (SAXS) measurements organize into core-shell complexes of short axis diameters 25-26 nm consisting of ~7 monomers. Using peptide arrays, we identify EGCG-binding sites in FapC's linker regions, C and N-terminal parts, and high amyloidogenic sequences located in the R2 and R3 repeats. We correlate our biophysical observations to biological impact by demonstrating that the extent of amyloid inhibition by the different inhibitors correlated with their ability to reduce biofilm, highlighting the potential of anti-amyloid polyphenols as therapeutic agents against biofilm infections.}, } @article {pmid31717723, year = {2019}, author = {Janka, E and Carvajal, D and Wang, S and Bakke, R and Dinamarca, C}, title = {Treatment of Metformin-Containing Wastewater by a Hybrid Vertical Anaerobic Biofilm-Reactor (HyVAB).}, journal = {International journal of environmental research and public health}, volume = {16}, number = {21}, pages = {}, pmid = {31717723}, issn = {1660-4601}, mesh = {Anaerobiosis ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Hypoglycemic Agents/*isolation & purification ; Metformin/*isolation & purification ; Waste Disposal, Fluid ; Wastewater/*chemistry ; *Water Purification ; }, abstract = {Several series of batch and continuous experiments were performed to investigate the removal of metformin and other contaminants from two wastewaters: wastewater I (WWI) containing 4 mg/L metformin and wastewater II (WWII) containing 110 g/L butanol. Biomethane potential (BMP) tests on WWII showed 77% of total chemical oxygen demand (tCOD = 110 g/L) degradability, and no apparent inhibition effects were observed. BMP tests on WWI showed an apparent inhibitory effect reflected in lower biogas production with increasing metformin concentration in the wastewater. Continuous flow hybrid vertical anaerobic biofilm (HyVAB[®]) experiments were consistent with the batch test findings. It was necessary to co-digest WWI (metformin) with WWII (easily degradable organics) to achieve complete metformin removal. After a period of adaptation, WWI and WWII co-digestion achieved up to 98% tCOD removal and 100% metformin removal. Most of the contaminants were removed in the anaerobic section of the HyVAB[®], which implies that higher chemical oxygen demand (COD) loads than tested here are possible, given some optimization. The pilot reactor was able to manage organic loads of 11 g COD/d and above 10 mg/L metformin with a removal of 98% and 100% for tCOD and metformin, respectively.}, } @article {pmid31715659, year = {2020}, author = {Huang, Z and Wu, L and Li, X and Ma, L and Borriss, R and Gao, X}, title = {Zn(II) suppresses biofilm formation in Bacillus amyloliquefaciens by inactivation of the Mn(II) uptake.}, journal = {Environmental microbiology}, volume = {22}, number = {4}, pages = {1547-1558}, doi = {10.1111/1462-2920.14859}, pmid = {31715659}, issn = {1462-2920}, support = {2017YFD0200400//the National Key Research and Development Program of China/International ; 2016M601834//the China Postdoctoral Science Foundation/International ; 2018T110512//the China Postdoctoral Science Foundation/International ; 31701833//the National Natural Science Foundation of China/International ; BK20170712//the Natural Science Foundation of Jiangsu Province/International ; KJQN201811//the Special Fund for the Fundamental Research Funds for the Central Universities/International ; }, mesh = {Bacillus amyloliquefaciens/*drug effects/physiology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Biological Transport/drug effects ; Histidine Kinase/metabolism ; Manganese/*metabolism ; Operon ; Zinc/*pharmacology ; }, abstract = {Biofilms are architecturally complex communities of microbial cells held together by a self-produced extracellular matrix. Considerable research has focused on the environmental signals that trigger or inhibit biofilm formation by affecting cellular signalling pathways; however, response to soil cues in plant-associated Bacillus has remained largely unaddressed. Therefore, we aimed to investigate the effect of Zn(II) ions in biofilm formation of Bacillus amyloliquefaciens FZB42. We demonstrated that the biofilm formation of B. amyloliquefaciens FZB42 was abolished by Zn(II) at non-deleterious concentrations. Moreover, Zn(II) blocked matrix exopolysaccharide and TasA accumulations. Furthermore, the presence of Zn(II) suppressed expression of the response regulator Spo0F but not of sensor histidine kinases KinA-D. Suppression of phosphorelay by excess Zn interferes with sinI induction under biofilm-inducing conditions, leading to repression of transcription of operons epsA-O and tapA-sigW-tasA. Addition of Zn(II) decreased the intracellular Mn(II) level by competing for binding to the solute-binding protein MntA during Mn(II) uptake. These results suggest that the metal ion Zn(II) has a negative effect on biofilm formation in the plant growth promoting and biocontrol bacterium B. amyloliquefaciens FZB42.}, } @article {pmid31715042, year = {2020}, author = {Peng, J and Kumar, K and Gross, M and Kunetz, T and Wen, Z}, title = {Removal of total dissolved solids from wastewater using a revolving algal biofilm reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {92}, number = {5}, pages = {766-778}, doi = {10.1002/wer.1273}, pmid = {31715042}, issn = {1554-7531}, support = {14-062-AP//Metropolitan Water Reclamation District of Greater Chicago/ ; }, mesh = {Biofilms ; Biomass ; *Extracellular Polymeric Substance Matrix ; Sulfates ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Total dissolved solids (TDS) comprising inorganic salts and organic matters are pollutants of concern to aquatic systems and water for human use. This work aimed to investigate the use of revolving algal biofilm (RAB) reactors as a sustainable and environmental friendly method to remove TDS from industrial effluents and municipal wastewaters. The wastewaters contained chloride, sodium, potassium, calcium, magnesium, and sulfate as the major components. The RAB reactors fed with synthetic industrial effluent with high TDS level demonstrated the best algal growth, with the highest TDS removal efficiency (27%) and removal rate (2,783 mg/L-day and 19,530 mg/m[2] -day). A suspended algal culture system only removed 3% TDS from the same wastewater. The TDS removal by the RAB reactors was considered due to several mechanisms such as absorption by the algae cells, adsorption by extracellular polymeric substance of the biofilm, and/or precipitation. Collectively, this research shows that the RAB reactors can serve as an efficient system in wastewater remediation for TDS removal. PRACTITIONER POINTS: Total dissolved solids (TDS) in wastewater are pollutants of concern. The RAB reactors can remove TDS from various types of wastewater. The RAB reactors removed TDS by adsorbing ions elements such as Cl, Na, K, Ca, Mg, and S. The algal biomass absorbs ions through extracellular polymeric substance.}, } @article {pmid31713778, year = {2020}, author = {Vaknin, M and Steinberg, D and Featherstone, JD and Feuerstein, O}, title = {Exposure of Streptococcus mutans and Streptococcus sanguinis to blue light in an oral biofilm model.}, journal = {Lasers in medical science}, volume = {35}, number = {3}, pages = {709-718}, pmid = {31713778}, issn = {1435-604X}, support = {2013445//United States-Israel Binational Science Foundation/ ; 2013445//United States - Israel Binational Science Foundation/ ; }, mesh = {Animals ; Biofilms/growth & development/*radiation effects ; Cattle ; Dental Enamel/microbiology/ultrastructure ; Gene Expression Regulation, Bacterial/radiation effects ; *Light ; *Models, Biological ; Mouth/*microbiology ; Streptococcus mutans/genetics/*radiation effects/ultrastructure ; Streptococcus sanguis/genetics/*radiation effects/ultrastructure ; }, abstract = {The potential anti-cariogenic effect of blue light was evaluated using an oral biofilm model. Two species, Streptococcus mutans and Streptococcus sanguinis, were cultivated ex vivo on bovine enamel blocks for 24 h, either separately or mixed together, then exposed to blue light (wavelengths 400-500 nm) using 112 J/cm[2]. Twenty four or 48 h after exposure to light the biofilm structure and biomass were characterized and quantified using SEM and qPCR, respectively. Bacterial viability was analyzed by CLSM using live/dead bacterial staining. Gene expression was examined by RT-qPCR. After exposure to light, S. mutans biomass in mono-species biofilm was increased mainly by dead bacteria, relative to control. However, the bacterial biomass of S. mutans when grown in mixed biofilm and of S. sanguinis in mono-species biofilm was reduced after light exposure, with no significant change in viability when compared to control. Furthermore, when grown separately, an upregulation of gene expression related to biofilm formation of S. mutans, and downregulation of similar genes of S. sanguinis, were measured 24 h after exposure to blue light. However, in mixed biofilm, a downregulation of those genes in both species was observed, although not significant in S. mutans. In conclusion, blue light seems to effectively alter the bacterial biomass by reducing the viability and virulence characteristics in both bacterial species and may promote the anti-cariogenic balance between them, when grown in a mixed biofilm. Therefore, exposure of oral biofilm to blue light has the potential to serve as a complementary approach in preventive dentistry.}, } @article {pmid31713454, year = {2019}, author = {Rollin-Pinheiro, R and Rochetti, VP and Xisto, MIDDS and Liporagi-Lopes, LC and Bastos, B and Rella, A and Singh, A and Rozental, S and Del Poeta, M and Barreto-Bergter, E}, title = {Sphingolipid biosynthetic pathway is crucial for growth, biofilm formation and membrane integrity of Scedosporium boydii.}, journal = {Future medicinal chemistry}, volume = {11}, number = {22}, pages = {2905-2917}, pmid = {31713454}, issn = {1756-8927}, support = {I01 BX002624/BX/BLRD VA/United States ; R01 AI116420/AI/NIAID NIH HHS/United States ; R01 AI125770/AI/NIAID NIH HHS/United States ; R01 AI136934/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cell Membrane/metabolism ; Fatty Acids, Monounsaturated/metabolism ; Meperidine/analogs & derivatives/metabolism ; Scedosporium/*metabolism ; Sphingolipids/*biosynthesis ; }, abstract = {Aim: Glycosphingolipids are conserved lipids displaying a variety of functions in fungal cells, such as determination of cell polarity and virulence. They have been considered as potent targets for new antifungal drugs. The present work aimed to test two inhibitors, myriocin and DL-threo-1-Phenyl-2-palmitoylamino-3-morpholino-1-propanol, in Scedosporium boydii, a pathogenic fungus which causes a wide range of disease. Materials & methods: Mass spectrometry, microscopy and cell biology approaches showed that treatment with both inhibitors led to defects in fungal growth and membrane integrity, and caused an increased susceptibility to the current antifungal agents. Conclusion: These data demonstrate the antifungal potential of drugs inhibiting sphingolipid biosynthesis, as well as the usefulness of sphingolipids as promising targets for the development of new therapeutic options.}, } @article {pmid31712267, year = {2019}, author = {Harro, JM and Achermann, Y and Freiberg, JA and Allison, DL and Brao, KJ and Marinos, DP and Sanjari, S and Leid, JG and Shirtliff, ME}, title = {Clearance of Staphylococcus aureus from In Vivo Models of Chronic Infection by Immunization Requires Both Planktonic and Biofilm Antigens.}, journal = {Infection and immunity}, volume = {88}, number = {1}, pages = {}, pmid = {31712267}, issn = {1098-5522}, mesh = {Animals ; Antibodies, Bacterial/administration & dosage/immunology ; Antigens, Bacterial/*immunology ; Disease Models, Animal ; Immunization, Passive ; Immunoglobulin G/administration & dosage/immunology ; Mice, Inbred BALB C ; Rabbits ; Staphylococcal Infections/*immunology/*prevention & control ; Staphylococcal Vaccines/administration & dosage/*immunology ; Staphylococcus aureus/*immunology ; Survival Analysis ; Treatment Outcome ; }, abstract = {Staphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an antistaphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-embedded bacterial populations. However, the addition of antibiotics was required to eradicate remaining planktonic populations. In this study, a planktonic upregulated antigen was combined with the quadrivalent vaccine to remove the need for antibiotic therapy. Immunization with this pentavalent vaccine followed by intraperitoneal challenge of BALB/c mice with S. aureus resulted in 16.7% and 91.7% mortality in pentavalent vaccine and control groups, respectively (P < 0.001). Complete bacterial elimination was found in 66.7% of the pentavalent cohort, while only 8.3% of the control animals cleared the infection (P < 0.05). Further protective efficacy was observed in immunized rabbits following intramedullary challenge with S. aureus, where 62.5% of the pentavalent cohort completely cleared the infection, versus none of the control animals (P < 0.05). Passive immunization of BALB/c mice with serum IgG against the vaccine antigens prior to intraperitoneal challenge with S. aureus prevented mortality in 100% of mice and eliminated bacteria in 33.3% of the challenged mice. These results demonstrate that targeting both the planktonic and biofilm stages with the pentavalent vaccine or the IgG elicited by immunization can effectively protect against S. aureus infection.}, } @article {pmid31710602, year = {2019}, author = {Bridges, AA and Bassler, BL}, title = {The intragenus and interspecies quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal.}, journal = {PLoS biology}, volume = {17}, number = {11}, pages = {e3000429}, pmid = {31710602}, issn = {1545-7885}, support = {R37 GM065859/GM/NIGMS NIH HHS/United States ; DRG-2302-17/HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/genetics ; Homoserine/analogs & derivatives/metabolism ; Ketones/metabolism ; Lactones/metabolism ; Quorum Sensing/*physiology ; Signal Transduction ; Vibrio cholerae/*metabolism ; Virulence ; }, abstract = {Vibrio cholerae possesses multiple quorum-sensing (QS) systems that control virulence and biofilm formation among other traits. At low cell densities, when QS autoinducers are absent, V. cholerae forms biofilms. At high cell densities, when autoinducers have accumulated, biofilm formation is repressed, and dispersal occurs. Here, we focus on the roles of two well-characterized QS autoinducers that function in parallel. One autoinducer, called cholerae autoinducer-1 (CAI-1), is used to measure Vibrio abundance, and the other autoinducer, called autoinducer-2 (AI-2), is widely produced by different bacterial species and presumed to enable V. cholerae to assess the total bacterial cell density of the vicinal community. The two V. cholerae autoinducers funnel information into a shared signal relay pathway. This feature of the QS system architecture has made it difficult to understand how specific information can be extracted from each autoinducer, how the autoinducers might drive distinct output behaviors, and, in turn, how the bacteria use QS to distinguish kin from nonkin in bacterial communities. We develop a live-cell biofilm formation and dispersal assay that allows examination of the individual and combined roles of the two autoinducers in controlling V. cholerae behavior. We show that the QS system works as a coincidence detector in which both autoinducers must be present simultaneously for repression of biofilm formation to occur. Within that context, the CAI-1 QS pathway is activated when only a few V. cholerae cells are present, whereas the AI-2 pathway is activated only at much higher cell density. The consequence of this asymmetry is that exogenous sources of AI-2, but not CAI-1, contribute to satisfying the coincidence detector to repress biofilm formation and promote dispersal. We propose that V. cholerae uses CAI-1 to verify that some of its kin are present before committing to the high-cell-density QS mode, but it is, in fact, the broadly made autoinducer AI-2 that sets the pace of the V. cholerae QS program. This first report of unique roles for the different V. cholerae autoinducers suggests that detection of kin fosters a distinct outcome from detection of nonkin.}, } @article {pmid31710252, year = {2019}, author = {Rossoni, RD and de Barros, PP and Lopes, LADC and Ribeiro, FC and Nakatsuka, T and Kasaba, H and Junqueira, JC}, title = {Effects of surface pre-reacted glass-ionomer (S-PRG) eluate on Candida spp.: antifungal activity, anti-biofilm properties, and protective effects on Galleria mellonella against C. albicans infection.}, journal = {Biofouling}, volume = {35}, number = {9}, pages = {997-1006}, doi = {10.1080/08927014.2019.1686485}, pmid = {31710252}, issn = {1029-2454}, mesh = {Acrylic Resins/pharmacology ; Animals ; Antifungal Agents/*pharmacology/toxicity ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development ; Candidiasis, Oral/*prevention & control ; Glass Ionomer Cements/*pharmacology/toxicity ; Larva/drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Moths/*drug effects/microbiology ; Silicon Dioxide/pharmacology ; }, abstract = {Surface pre-reacted glass-ionomer (S-PRG) is a bioactive filler produced by PRG technology, which is applied to various dental materials. The inhibitory effects of S-PRG eluate against Candida, the most common fungal oral pathogen, were investigated. Minimum inhibitory concentrations (MIC) and anti-biofilm activities were tested against Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis. For the in vivo study, Galleria mellonella was used as a model to evaluate the effects of S-PRG on toxicity, hemocyte counts and candidiasis. The MIC of S-PRG ranged from 5 to 40% (v/v). S-PRG eluate exhibited anti-biofilm activity for all the Candida species tested. Furthermore, injection of S-PRG eluate into G. mellonella was not toxic to the larvae and protected G. mellonella against experimental candidiasis. In addition, S-PRG eluate inhibited biofilm formation by C. albicans, C. glabrata, C. krusei, and C. tropicalis and exerted protective effects on G. mellonella against experimental candidiasis in vivo.}, } @article {pmid31709555, year = {2020}, author = {Lange, MD and Farmer, BD and Abernathy, J}, title = {Vertebrate mucus stimulates biofilm development and upregulates iron acquisition genes in Flavobacterium columnare.}, journal = {Journal of fish diseases}, volume = {43}, number = {1}, pages = {101-110}, doi = {10.1111/jfd.13103}, pmid = {31709555}, issn = {1365-2761}, support = {6010-32000-026-00-D//USDA-ARS Research Project/ ; 6028-32000-007-00-D//USDA-ARS Research Project/ ; }, mesh = {Animals ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Fish Diseases/*microbiology ; Flavobacteriaceae Infections/microbiology/*veterinary ; Flavobacterium/growth & development/*physiology ; Gene Expression Regulation, Bacterial ; Iron/metabolism ; Mucus/*physiology ; }, abstract = {Columnaris disease is responsible for substantial losses throughout the production of many freshwater fish species. One of the ways in which the bacterium Flavobacterium columnare is so effective in initiating disease is through the formation of biofilms on fish skin and gills. To further explore the interaction between host factors and bacterial cells, we assayed the ability of vertebrate mucus to enhance F. columnare biofilm development. Different concentrations of catfish, tilapia and pig mucus (5-60 µg/ml) increased biofilm growth at varying degrees among F. columnare isolates. Our data suggest that vertebrate mucus acts as a signalling molecule for the development of F. columnare biofilms; however, there are clear disparities in how individual isolates respond to different mucus fractions to stimulate biofilms. The expression of iron acquisition genes among two genomovar II isolates showed that ferroxidase, TonB receptor and the siderophore synthetase gene were all significantly upregulated among F. columnare biofilms. Interestingly, the siderophore acetyltransferase gene was only shown to be significantly upregulated in one of the genomovar II isolates. This work provides insight into our understanding of the interaction between F. columnare and vertebrate mucus, which likely contributes to the growth of planktonic cells and the transition into biofilms.}, } @article {pmid31709419, year = {2019}, author = {Wang, Z and Chen, XM and Ni, BJ and Tang, YN and Zhao, HP}, title = {Model-based assessment of chromate reduction and nitrate effect in a methane-based membrane biofilm reactor.}, journal = {Water research X}, volume = {5}, number = {}, pages = {100037}, pmid = {31709419}, issn = {2589-9147}, abstract = {Chromate contamination can pose a high risk to both the environment and public health. Previous studies have shown that CH4-based membrane biofilm reactor (MBfR) is a promising method for chromate removal. In this study, we developed a multispecies biofilm model to study chromate reduction and its interaction with nitrate reduction in a CH4-based MBfR. The model-simulated results were consistent with the experimental data reported in the literature. The model showed that the presence of nitrate in the influent promoted the growth of heterotrophs, while suppressing methanotrophs and chromate reducers. Moreover, it indicated that a biofilm thickness of 150 μm and an influent dissolved oxygen concentration of 0.5 mg O2/L could improve the reactor performance by increasing the chromate removal efficiency under the simulated conditions.}, } @article {pmid31708908, year = {2019}, author = {She, P and Zhou, L and Li, S and Liu, Y and Xu, L and Chen, L and Luo, Z and Wu, Y}, title = {Synergistic Microbicidal Effect of Auranofin and Antibiotics Against Planktonic and Biofilm-Encased S. aureus and E. faecalis.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2453}, pmid = {31708908}, issn = {1664-302X}, abstract = {Methicillin-resistant/susceptible Staphylococcus aureus (MRSA/MSSA) and Enterococcus faecalis strains are often found in community- and hospital-acquired infections. The single use of conventional antibiotics hardly completely kills the bacterial cells of interest, especially in the form of biofilms. Thus, drug repurposing and antimicrobial combination are promising ways to solve this problem. Antimicrobial susceptibility assays against cocci in a suspension and in a biofilm mode of growth were performed with broth microdilution methods. Checkerboard assays and the cutaneous mouse infection model were used to examine the activity of auranofin and conventional antibiotics alone and in combination. In the present study, auranofin possesses potent antimicrobial activities against both planktonic cells and biofilms with minimum inhibitory concentrations ranging 0.125-0.5 mg/L. Auranofin in combination with linezolid or fosfomycin showed synergistic antimicrobial activities against S. aureus MSSA and MRSA both in vitro and in vivo. Similarly, auranofin also behaved synergistic effect with chloramphenicol against E. faecalis. Additionally, auranofin improved the antibiofilm efficacy of chloramphenicol and linezolid, even on the biofilms grown on a catheter surface. Though, S. epidermidis showed significant susceptibility to AF treatment, no synergistic antimicrobial effects were observed with antibiotics we tested. In all, the use of a combination of auranofin with linezolid, fosfomycin, and chloramphenicol can provide a synergistic microbicidal effect in vitro and in vivo, which rapidly enhances antimicrobial activity and may help prevent or delay the emergence of resistance.}, } @article {pmid31708905, year = {2019}, author = {Millen, S and Gross, C and Donhauser, N and Mann, MC and Péloponèse, JM and Thoma-Kress, AK}, title = {Collagen IV (COL4A1, COL4A2), a Component of the Viral Biofilm, Is Induced by the HTLV-1 Oncoprotein Tax and Impacts Virus Transmission.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2439}, pmid = {31708905}, issn = {1664-302X}, abstract = {Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for Adult T-Cell Leukemia/Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). HTLV-1 infects CD4[+] T-cells via cell-to-cell transmission requiring reorganization of the cytoskeleton and expression of the viral transactivator and oncoprotein Tax. Viruses spread at the virological synapse (VS), a virus-induced specialized cell-cell contact, by polarized budding into synaptic clefts, and by cell surface transfer of viral biofilms (VBs). Since little is known about Tax's role in formation of the VB, we asked which component of the VB is regulated by Tax and important for HTLV-1 transmission. Collagens are not only structural proteins of the extracellular matrix and basal membrane but also represent an important component of the VB. Here, we report that among the collagens known to be present in VBs, COL4 is specifically upregulated in the presence of HTLV-1 infection. Further, we found that transient expression of Tax is sufficient to induce COL4A1 and COL4A2 transcripts in Jurkat and CCRF-CEM T-cells, while robust induction of COL4 protein requires continuous Tax expression as shown in Tax-transformed T-cell lines. Repression of Tax led to a significant reduction of COL4A1/A2 transcripts and COL4 protein. Mechanistically, luciferase-based promoter studies indicate that Tax activates the COL4A2 and, to a less extent, the COL4A1 promoter. Imaging showing partial co-localization of COL4 with the viral Gag protein in VBs at the VS and transfer of COL4 and Gag to target cells suggests a role of COL4 in VB formation. Strikingly, in chronically infected C91-PL cells, knockout of COL4A2 impaired Gag transfer between infected T-cells and acceptor T-cells, while release of virus-like particles was unaffected. Taken together, we identified COL4 (COL4A1, COL4A2) as a component of the VB and a novel cellular target of Tax with COL4A2 appearing to impact virus transmission. Thus, this study is the first to provide a link between Tax's activity and VB formation by hijacking COL4 protein functions.}, } @article {pmid31706910, year = {2019}, author = {Das, P and Karankar, VS}, title = {New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review.}, journal = {Journal of microbiological methods}, volume = {167}, number = {}, pages = {105766}, doi = {10.1016/j.mimet.2019.105766}, pmid = {31706910}, issn = {1872-8359}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects/pathogenicity ; Bacterial Infections/drug therapy ; Biofilms/*drug effects ; Humans ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/pharmacology ; }, abstract = {Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activitiesboth singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbesthe efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganismsbeing embedded in the meshwork of the biofilmevade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge tooas they not only destroy the biofilms but also lessen the doses of antibiotics requiredwhen administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledgefocuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.}, } @article {pmid31706760, year = {2020}, author = {Lawrence, JR and Paule, A and Swerhone, GDW and Roy, J and Grigoryan, AA and Dynes, JJ and Chekabab, SM and Korber, DR}, title = {Microscale and molecular analyses of river biofilm communities treated with microgram levels of cerium oxide nanoparticles indicate limited but significant effects.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {256}, number = {}, pages = {113515}, doi = {10.1016/j.envpol.2019.113515}, pmid = {31706760}, issn = {1873-6424}, mesh = {Biofilms/*growth & development ; Biomass ; Cerium/*toxicity ; Cyanobacteria/metabolism ; Environmental Monitoring ; Nanoparticles/*toxicity ; RNA, Ribosomal, 16S ; Rivers/*microbiology ; }, abstract = {Cerium oxide (CeO2) nanoparticles are used as in-fuel catalysts and in manufacturing processes, creating a potential for release to aquatic environments. Exposures at 1 and 10 μg/L CeO2-nanoparticles were made to assess effects during the development of river biofilm communities. Scanning transmission x-ray microscopy (STXM) indicated extensive sorption of nanoparticles to the community and co-localization with lipid moieties. Following 8 weeks of development, polycarbonate coupons were removed from the reactors and used for molecular analyses, denaturing gradient gel electrophoresis analysis (DGGE-16S rRNA) and 16S rRNA amplicon sequencing. Microscopic imaging of the biofilm communities (bacterial, photosynthetic biomass, exopolymer composition, thickness, protozoan numbers), as well as carbon substrate utilization fingerprinting was performed. There was a trend toward reduced photosynthetic biomass, but no significant effects of CeO2 exposure were found on photosynthetic and bacterial biomass or biofilm thickness. Sole carbon source utilization analyses indicated increased utilization of 10 carbon sources in the carbohydrate, carboxylic acid and amino acids categories related to CeO2 exposures; however, predominantly, no significant effects (p < 0.05) were detected. Measures of microbial diversity, lectin binding affinities of exopolymeric substances and results of DGGE analyses, indicated significant changes to community composition (p < 0.05) with CeO2 exposure. Increased binding of the lectin Canavalia ensiformis was observed, consistent with changes in bacterial-associated polymers. Whereas, no significant changes were observed in binding to residues associated with algal and cyanobacterial exopolymers. 16S rRNA amplicon sequencing of community DNA indicated changes in diversity and shifts in community composition; however, these did not trend with increasing CeO2 exposure. Counting of protozoans in the biofilm communities indicated no significant effects on this trophic level. Thus, based on biomass and functional measures, CeO2 nanoparticles did not appear to have significant effects; however, there was evidence of selection pressure resulting in significant changes in microbial community composition.}, } @article {pmid31706043, year = {2020}, author = {Keren-Paz, A and Kolodkin-Gal, I}, title = {A brick in the wall: Discovering a novel mineral component of the biofilm extracellular matrix.}, journal = {New biotechnology}, volume = {56}, number = {}, pages = {9-15}, doi = {10.1016/j.nbt.2019.11.002}, pmid = {31706043}, issn = {1876-4347}, mesh = {Bacillus subtilis/*chemistry/metabolism ; *Biofilms ; Extracellular Matrix/*chemistry/metabolism ; Minerals/*analysis ; Mycobacterium smegmatis/*chemistry/metabolism ; }, abstract = {Multicellular bacterial communities, known as biofilms, have been thought to be held together solely by a self-produced organic extracellular matrix (ECM). However, new evidence for a missed mineral constituent of ECM in both Gram-positive and Gram-negative bacterial species, is accumulating. Study of two phylogenetically distinct bacteria, Bacillus subtilis and Mycobacterium smegmatis, identified a novel mechanism crucial for proper biofilm development and architecture - an active, genetically regulated, production of crystalline calcite. The calcite scaffolds stabilize bacterial biofilms, limit penetration of small molecule solutes such as antibiotics and play a conserved role in the assembly of those complex differentiated multicellular communities. This review discusses the recently discovered structural and functional roles of extracellular minerals in biofilms. It is proposed that it is time for a more complete view of the ECM as a complex combination of organic and nonorganic materials, especially in the light of the possible implications for treatment of biofilm infections.}, } @article {pmid31705932, year = {2020}, author = {Sood, U and Singh, DN and Hira, P and Lee, JK and Kalia, VC and Lal, R and Shakarad, M}, title = {Rapid and solitary production of mono-rhamnolipid biosurfactant and biofilm inhibiting pyocyanin by a taxonomic outlier Pseudomonas aeruginosa strain CR1.}, journal = {Journal of biotechnology}, volume = {307}, number = {}, pages = {98-106}, doi = {10.1016/j.jbiotec.2019.11.004}, pmid = {31705932}, issn = {1873-4863}, mesh = {Biofilms/*drug effects ; Carbon/metabolism ; Genome, Bacterial/*genetics ; Glycolipids/chemistry/*metabolism ; Pseudomonas aeruginosa/genetics/growth & development/*metabolism ; Pyocyanine/chemistry/*metabolism/pharmacology ; Surface-Active Agents/chemistry/*metabolism ; }, abstract = {Biosurfactant - Rhamnolipids (RLs) and antibacterial toxin - pyocyanin (PYO) produced by Pseudomonas aeruginosa strains have great potential for biotechnological applications. Generally, RLs are produced as a mixture of di-rhamnolipids (di-RLs) and mono-rhamnolipids (mono-RLs). Mono-RLs possess superior emulsification and antimicrobial properties and are costlier than di-RLs. In this study, a taxonomic outlier P. aeruginosa strain CR1 isolated from rhizosphere soil was explored for mono-RLs and PYO production. Phylogenetically strain CR1 resembles avirulent outlier P. aeruginosa strain ATCC9027, lacks archetypical virulence genes and harbors unique pathways for the synthesis of solely mono-RLs and PYO. Strain CR1 produced RL biosurfactant which efficiently emulsified hydrocarbons, showed hemolysis and inhibited Bacillus subtilis. At 37 °C, strain CR1 exclusively produced 21.77 g L[-1] and 19.22 g L[-1] rhamnolipid in glycerol amended Luria Bertani (LB) medium and basal medium amended with rice bran oil, respectively after 54 h growth. Besides RL production was unaffected under varying nitrogen sources. Structural characterization using FTIR, TLC, and LC-MS confirmed that strain CR1 exclusively produced mono-RLs, majorly dominated by Rha-C10-C10, Rha-C10-C8, and CH3-Rha-C12:2-C10:1. The compound was stable over a wide pH range (4-12), salinity (25%) and 100 °C indicating its applicability under harsh environmental conditions. In addition, strain CR1 produced 4.5 μg mL[-1] PYO, which could efficiently inhibit biofilm formation by Bacillus species. The environmental outlier strain CR1 can be used for the industrial production of biotechnologically important mono-RLs and PYO.}, } @article {pmid31705133, year = {2020}, author = {Marquès, C and Collin, V and Franceschi, C and Charbonnel, N and Chatellier, S and Forestier, C}, title = {Fosfomycin and Staphylococcus aureus: transcriptomic approach to assess effect on biofilm, and fate of unattached cells.}, journal = {The Journal of antibiotics}, volume = {73}, number = {2}, pages = {91-100}, pmid = {31705133}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fosfomycin/*pharmacology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Staphylococcus aureus/*drug effects/genetics ; Transcriptome ; }, abstract = {Interest has been rekindled in the old antibiotic fosfomycin, partly because of its ability to penetrate biofilm. Using a transcriptomic approach, we investigated the modifications induced by fosfomycin in sessile cells of a clinical Staphylococcus aureus isolated from a device-associated infection. Cells still able to form biofilm after 4 h of incubation in the presence of subinhibitory concentrations of fosfomycin and cells from 24-h-old biofilm later submitted to fosfomycin had 6.77% and 9.41%, respectively, of differentially expressed genes compared with their antibiotic-free control. Fosfomycin induced mostly downregulation of genes assigned to nucleotide, amino acid and carbohydrate transport, and metabolism. Adhesins and capsular biosynthesis proteins encoding genes were downregulated in fosfomycin-grown biofilm, whereas the murein hydrolase regulator lgrA and a D-lactate dehydrogenase-encoding gene were upregulated. In fosfomycin-treated biofilm, the expression of genes encoding adhesins, the cell wall biosynthesis protein ScdA, and to a lesser extent the fosfomycin target MurA was also decreased. Unattached cells surrounding fosfomycin-grown biofilm showed greater ability to form aggregates than their counterparts obtained without fosfomycin. Reducing their global metabolism and lowering cell wall turnover would allow some S. aureus cells to grow in biofilm despite fosfomycin stress while promoting hyperadherent phenotype in the vicinity of the fosfomycin-treated biofilm.}, } @article {pmid31704413, year = {2020}, author = {Rehman, ZU and Fortunato, L and Cheng, T and Leiknes, T}, title = {Metagenomic analysis of sludge and early-stage biofilm communities of a submerged membrane bioreactor.}, journal = {The Science of the total environment}, volume = {701}, number = {}, pages = {134682}, doi = {10.1016/j.scitotenv.2019.134682}, pmid = {31704413}, issn = {1879-1026}, mesh = {*Biofilms ; Biofouling ; Bioreactors/*microbiology ; Membranes, Artificial ; Metagenome ; *Microbiota ; Sewage/microbiology ; *Waste Disposal, Fluid ; }, abstract = {Biofilm formation on membranes in activated sludge membrane bioreactors (MBR), commonly identified as biofouling, is a significant problem for MBR operations. A better understanding of microbial species involved in the biofilm formation is needed to develop anti-biofilm measures. A read-based and genome-resolved shotgun metagenomic approach was applied to characterize the composition and functional potential of the sludge and early stage biofilm microbial communities in an MBR process. Read-based analysis revealed that the prevalence of different phyla are relatively similar in both the sludge and biofilm samples, with Proteobacteria as the most dominant, followed by Chloroflexi, Bacteroidetes and Planctomycetes. However, the relative abundance of these phyla slightly varies between the sludge and biofilm. Phyla such as Actinobacteria, bacterial candidate phyla, Chlamydiae, Cyanobacteria/Melainabacteria and Firmicutes are 2 to 4 times more abundant in the biofilm than in the sludge. At the genus level, genera belonging to Proteobacteria (Legionella, Caulobacter, Sphingomonas, Acinetobacter and Rhizobium), Cyanobacteria (Hassallia), and Spirochaetes (Turneriella) are at least twice more abundant in the biofilm. These genera, especially those belonging to Phylum Proteobacteria, are known to play an important role in the formation of biofilms on surfaces. The Alpha diversity is found slightly higher in the biofilm, compared with sludge samples. Functional classification of reads through the SEED subsystem shows that functional classes such as those involved in the metabolism of various molecules are significantly different in the biofilm and sludge. A phylogenomic analysis of the six extracted metagenome assembled genomes (MAGs) shows that three MAGs belong to Proteobacteria, and one MAG belong to each of Chloroflexi, Bacteroidetes and Planctomycetes. The relative abundance of the MAG belonging to Alphaproteobacteria is higher in the biofilm. A functional potential analysis of the MAGs reveals their potential to metabolize carbon and nitrogen sources, as well as the prevalence of antibiotic resistance genes.}, } @article {pmid31703923, year = {2020}, author = {Alfaifi, AA and Lin, WS and Aldhaian, BA and Levon, JA and Gregory, RL}, title = {Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine.}, journal = {The Journal of prosthetic dentistry}, volume = {123}, number = {6}, pages = {875-879}, doi = {10.1016/j.prosdent.2019.09.007}, pmid = {31703923}, issn = {1097-6841}, mesh = {Acrylic Resins ; Biofilms ; Caffeine ; *Candida albicans ; *Denture Bases ; Dentures ; Nicotine ; }, abstract = {STATEMENT OF PROBLEM: Candida albicans has been implicated in denture stomatitis, and this effect is exacerbated by nicotine exposure. However, studies have also suggested that caffeine exposure inhibits the growth of C. albicans. The interaction effects of nicotine and caffeine are not yet clear on the growth of C. albicans.

PURPOSE: The purpose of this in vitro study was to determine the effect of caffeine on metabolic activity and biofilm formation of C. albicans growing on acrylic denture resin while simultaneously exposed to nicotine and, if an effect were to be identified, whether this effect would vary depending on the caffeine concentration.

MATERIAL AND METHODS: A total of 240 acrylic resin specimens were divided into 2 equal groups (120 each). Specimens in one group were processed to measure C. albicans metabolic activity, and those in the other group were processed to measure C. albicans biofilm attachment. Ten subgroups (n=12) were established within each group with different concentration combinations of nicotine and caffeine to test the interaction effect. The first subgroup was designed as a negative control, containing 0 mg/mL of nicotine and caffeine. The following subgroups all contained 8.00 mg/mL of nicotine, and the caffeine concentrations were prepared at the following 9 levels: 0, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00, 16.00, and 32.00 mg/mL. Metabolic activity was measured by using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) assay. Biofilm attachment was measured by using spiral plating and calculated in terms of the number of colony-forming units (CFUs)/mL. Descriptive statistics and a 2-way ANOVA were conducted to determine whether the concentrations of nicotine and caffeine used affected the biofilm attachment and metabolic activity of C. albicans (α=.05).

RESULTS: The presence of 8 mg/mL of nicotine increased the metabolic activity and biofilm formation of C. albicans. When compared with the 0 mg/mL of caffeine and 8.00 mg/mL of nicotine group, caffeine from 1.00 to 4.00 mg/mL significantly increased C. albicans biofilm metabolic activity. Caffeine at 16.00 and 32.00 mg/mL significantly decreased C. albicans biofilm metabolic activity in the presence of 8 mg/mL of nicotine. Caffeine from 1.00 to 32.00 mg/mL significantly decreased the biofilm formation of C. albicans in the presence of 8 mg/mL of nicotine.

CONCLUSIONS: The presence of 8 mg/mL of nicotine alone increased the metabolic activity and biofilm formation of C. albicans. In the presence of 8 mg/mL of nicotine with different caffeine concentrations, the results suggest that, overall, caffeine at higher concentrations (16 and 32 mg/mL) inhibited the metabolic activity and biofilm formation of C. albicans on acrylic denture resin most.}, } @article {pmid31703877, year = {2020}, author = {Liu, F and Sun, Z and Wang, F and Liu, Y and Zhu, Y and Du, L and Wang, D and Xu, W}, title = {Inhibition of biofilm formation and exopolysaccharide synthesis of Enterococcus faecalis by phenyllactic acid.}, journal = {Food microbiology}, volume = {86}, number = {}, pages = {103344}, doi = {10.1016/j.fm.2019.103344}, pmid = {31703877}, issn = {1095-9998}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Enterococcus faecalis/*drug effects/growth & development/metabolism ; Lactates/*pharmacology ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/*biosynthesis ; }, abstract = {This study aimed to evaluate the inhibitory activity of phenyllactic acid (PLA) against the biofilm formation of Enterococcus faecalis and to explore its potential molecular mechanism. The MIC value of PLA that inhibited the growth of E. faecalis R612-Z1 in BHI broth was 5 mg/mL. PLAs at subinhibitory concentrations of 1.25 and 2.50 mg/mL were found to inhibit biofilm formation by a crystal violet staining assay. The cell swimming and swarming motilities of E. faecalis were reduced in the presence of PLA. An apparent decrease in the thickness of PLA-treated biofilms was observed through confocal laser scanning microscopy analysis. The exopolysaccharide production in E. faecalis biofilms was inhibited by EPS quantification assay and scanning electron microscopy (SEM). qRT-PCR analyses showed that PLA down-regulated the transcription of Ebp pili genes (ebpABC) and Epa polysaccharide genes (epaABE). PLA inhibited the biofilm formation by interfering with cell mobility and EPS production of E. faecalis. In addition, PLA at concentrations of 10.0 mg/mL can effectively control the bacterial cells in a three-day-old mature biofilm of E. faecalis grown on 24-well flat-bottom polystyrene plates and stainless-steel surfaces. Thus, PLA is potentially an effective agent to control E. faecalis biofilms.}, } @article {pmid31703870, year = {2020}, author = {Guo, D and Wang, S and Li, J and Bai, F and Yang, Y and Xu, Y and Liang, S and Xia, X and Wang, X and Shi, C}, title = {The antimicrobial activity of coenzyme Q0 against planktonic and biofilm forms of Cronobacter sakazakii.}, journal = {Food microbiology}, volume = {86}, number = {}, pages = {103337}, doi = {10.1016/j.fm.2019.103337}, pmid = {31703870}, issn = {1095-9998}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Cronobacter sakazakii/*drug effects/growth & development/physiology ; Infant Formula/analysis/microbiology ; Microbial Sensitivity Tests ; Plankton/drug effects/growth & development/physiology ; Ubiquinone/*analogs & derivatives/pharmacology ; }, abstract = {Coenzyme Q0 (CoQ0) has demonstrated antitumor, anti-inflammatory, and anti-angiogenic activities. Cronobacter sakazakii is an opportunistic foodborne pathogen associated with high mortality in neonates. In this study, the antimicrobial activity and possible antimicrobial mechanism of CoQ0 against C. sakazakii were investigated. Moreover, the inactivation effect of CoQ0 on C. sakazakii in biofilms was also evaluated. The minimum inhibitory concentration (MIC) of CoQ0 against C. sakazakii strains ranged from 0.1 to 0.2 mg/mL. Treatment caused cell membrane dysfunction, as evidenced by cell membrane hyperpolarization, decreased intracellular ATP concentration and cell membrane integrity, and changes in cellular morphology. CoQ0 combined with mild heat treatment (45, 50, or 55 °C) decreased the number of viable non-desiccated and desiccated C. sakazakii cells in a time- and dose-dependent manner in reconstituted infant milk. Furthermore, CoQ0 showed effective inactivation activity against C. sakazakii in biofilms on stainless steel, reducing the number of viable cells and damaging the structure of the biofilm. These findings suggest that CoQ0 has a strong inactivate effect on C. sakazakii and could be used in food production environments to effectively control C. sakazakii and reduce the number of illnesses associated with it.}, } @article {pmid31703863, year = {2020}, author = {Li, T and Sun, X and Chen, H and He, B and Mei, Y and Wang, D and Li, J}, title = {Methyl anthranilate: A novel quorum sensing inhibitor and anti-biofilm agent against Aeromonas sobria.}, journal = {Food microbiology}, volume = {86}, number = {}, pages = {103356}, doi = {10.1016/j.fm.2019.103356}, pmid = {31703863}, issn = {1095-9998}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Aeromonas/*drug effects/genetics/physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Quorum Sensing/*drug effects ; Virulence Factors/genetics/metabolism ; ortho-Aminobenzoates/*pharmacology ; }, abstract = {Quorum sensing (QS), bacterial cell-to-cell communication, is a gene regulatory mechanism that regulates virulence potential and biofilm formation in many pathogens. Aeromonas sobria, a common aquaculture pathogen, was isolated and identified by our laboratory from the deteriorated turbot, and its potential for virulence factors and biofilm production was regulated by QS system. In view of the interference with QS system, this study was aimed to investigate the effect of methyl anthranilate at sub-Minimum Inhibitory Concentrations (sub-MICs) on QS-regulated phenotypes in A. sobria. The results suggested that 0.5 μL/mL of methyl anthranilate evidently reduced biofilm formation (51.44%), swinging motility (74.86%), swarming motility (71.63%), protease activity (43.08%), and acyl-homoserine lactone (AHL) production. Furthermore, the real-time quantitative PCR (RT-qPCR) and in silico analysis showed that methyl anthranilate might inhibit QS system in A. sobria by interfering with the biosynthesis of AHL, as well as competitively binding with receptor protein. Therefore, our data indicated the feasibility of methyl anthranilate as a promising QS inhibitor and anti-biofilm agent for improving food safety.}, } @article {pmid31700653, year = {2019}, author = {Harrison, A and Hardison, RL and Wallace, RM and Fitch, J and Heimlich, DR and Bryan, MO and Dubois, L and John-Williams, LS and Sebra, RP and White, P and Moseley, MA and Thompson, JW and Justice, SS and Mason, KM}, title = {Reprioritization of biofilm metabolism is associated with nutrient adaptation and long-term survival of Haemophilus influenzae.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {33}, pmid = {31700653}, issn = {2055-5008}, support = {R01 AI139519/AI/NIAID NIH HHS/United States ; R01 DC013313/DC/NIDCD NIH HHS/United States ; }, mesh = {*Adaptation, Physiological ; Biofilms/*growth & development ; Gene Expression Profiling ; Haemophilus influenzae/*growth & development/*metabolism ; Heme/*metabolism ; Iron/metabolism ; Metabolism ; Metabolome ; *Microbial Viability ; Proteome/analysis ; }, abstract = {Nontypeable Haemophilus influenzae (NTHI) is a human-restricted pathogen with an essential requirement for heme-iron acquisition. We previously demonstrated that microevolution of NTHI promotes stationary phase survival in response to transient heme-iron restriction. In this study, we examine the metabolic contributions to biofilm formation using this evolved NTHI strain, RM33. Quantitative analyses identified 29 proteins, 55 transcripts, and 31 metabolites that significantly changed within in vitro biofilms formed by RM33. The synthesis of all enzymes within the tryptophan and glycogen pathways was significantly increased in biofilms formed by RM33 compared with the parental strain. In addition, increases were observed in metabolite transport, adhesin production, and DNA metabolism. Furthermore, we observed pyruvate as a pivotal point in the metabolic pathways associated with changes in cAMP phosphodiesterase activity during biofilm formation. Taken together, changes in central metabolism combined with increased stores of nutrients may serve to counterbalance nutrient sequestration.}, } @article {pmid31700570, year = {2019}, author = {Teves, A and Blanco, D and Casaretto, M and Torres, J and Alvarado, D and Jaramillo, DE}, title = {Effectiveness of different disinfection techniques of the root canal in the elimination of a multi-species biofilm.}, journal = {Journal of clinical and experimental dentistry}, volume = {11}, number = {11}, pages = {e978-e983}, pmid = {31700570}, issn = {1989-5488}, abstract = {BACKGROUND: The purpose of the study was to evaluate the effectiveness of different root canal disinfection techniques in the elimination of a multi-species biofilm from inside the root canal.

MATERIAL AND METHODS: Fifty mandibular first premolars were used in the present study, standardized to 11mm of root length, and instrumented with a reciprocation system Reciproc, (VDW GmbH, Munich, Germany) to a #50. Longitudinally sectioned halves of the roots were obtained and washed with NaOCl 4%, EDTA 17% and 5% sodium thiosulfate, and sterilized by autoclaving for 15 minutes at 121°C. A multi-species biofilm broth was developed with three strains of bacteria under laboratory conditions: Enterococcus faecalis ATTC 29212, Eikenella corrodens ATTC 23834, Streptococcus anginosus ATTC 33397. Roots were autoclaved and transferred to the broth for 4 days and then were subjected to either disinfection with sodium hypochlorite 4% and XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland) or chlorhexidine 2% with and without activation with XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland).

RESULTS: The evaluations of the biofilm elimination showed results that indicate that the 4% sodium hypochlorite group with positive pressure irrigation presented significant differences with the group that had irrigation with sodium hypochlorite activated with XP-endo Finisher and the chlorhexidine groups to 2% (P<0.05).

CONCLUSIONS: Chlorhexidine 2% activated with the XP-endo Finisher does not exert elimination or improved cleaning effect on the multi-species biofilm. Activation of sodium hypochlorite 4% improved the elimination of the multi-species biofilm. Key words:Biofilm, multispecies, chlorhexidine, sodium hypochlorite.}, } @article {pmid31699135, year = {2019}, author = {Theodora, NA and Dominika, V and Waturangi, DE}, title = {Screening and quantification of anti-quorum sensing and antibiofilm activities of phyllosphere bacteria against biofilm forming bacteria.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {732}, pmid = {31699135}, issn = {1756-0500}, support = {Penelitian Dasar 2019//Ristekdikti/ ; }, mesh = {Bacteria/*metabolism/ultrastructure ; Biofilms/*growth & development ; Microbial Sensitivity Tests ; Plant Leaves/*microbiology ; *Quorum Sensing ; }, abstract = {OBJECTIVE: The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria (Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa).

RESULTS: We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extract showed the largest turbid zone (1,27 cm) using isolate JB 14B with concentration of 10 mg/mL and the narrowest turbid zone isolate (1 cm) using JB 18B with concentration of 10 mg/mL. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria, it showed the highest biofilm inhibition (90%) and destruction activities (76%) against S. aureus.}, } @article {pmid31698068, year = {2019}, author = {Vinay, TN and Ray, AK and Avunje, S and Thangaraj, SK and Krishnappa, H and Viswanathan, B and Reddy, MA and Vijayan, KK and Patil, PK}, title = {Vibrio harveyi biofilm as immunostimulant candidate for high-health pacific white shrimp, Penaeus vannamei farming.}, journal = {Fish & shellfish immunology}, volume = {95}, number = {}, pages = {498-505}, doi = {10.1016/j.fsi.2019.11.004}, pmid = {31698068}, issn = {1095-9947}, mesh = {Adjuvants, Immunologic/*administration & dosage ; Administration, Oral ; Animals ; *Aquaculture ; Biofilms/*growth & development ; Chitin/metabolism ; Penaeidae/*immunology/*microbiology ; Seafood ; Vibrio/*immunology ; }, abstract = {The study was to develop Vibrio harveyi biofilm-based novel microbial product and its oral delivery for high health Penaeus vannamei farming. Yield of bacterial biofilm was optimized on chitin substrate (size: <360, 360-850 and 850-1250 μm; concentration: 0.3, 0.6 and 0.9%) in tryptone soy broth (0.15%). The biofilm was characterized by crystal violet assay, SEM and LSCM imaging; protein profiling by SDS-PAGE and LC-ESI-MS/MS. The immune stimulatory effect of the biofilm in yard experiments was evaluated by relative quantification of immune genes using real-time PCR effect on overall improvement on health status under field trials. The highest biofilm yield (6.13 ± 0.2 × 10[7] cfu/ml) was obtained at 0.6% of <360 μm chitin substrate. The biofilm formation was stabilized by 96 h of incubation at 30 °C. Protein profiling confirmed expression of six additional proteins (SDS-PAGE) and 11 proteins were differentially expressed (LC-ESI-MS/MS) in biofilm cells over free cells of V. harveyi. Oral administration of the biofilm for 48 h confirmed to enhance expression of antimicrobial peptides, penaeidin, crustin and lysozyme in P. vannamei. Further Oral administration of biofilm for two weeks to P. vannamei (1.8 ± 0.13 g) improved the growth (2.66 ± 0.06 g) and survival (84.44 ± 1.82%) compared to control (2.15 ± 0.03 g; 70.94 ± 0.66%) Nursery trials showed a significant reduction in occurrence of anatomical deformities like antenna cut (12.67 ± 0.66%), rostrum cut (4.66 ± 0.87%), and tail rot (3.33 ± 0.88%), compared to animals fed with normal diet which was 24.33 ± 2.72; 14 ± 1.52 and 10.66 ± 1.45% respectively. In vitro and in vivo studies suggest inactivated biofilm cells of V. harveyi on chitin substrate express additional antigenic proteins and when administered orally through feed at regular intervals stimulates immune response and improve growth, survival and health status of shrimp.}, } @article {pmid31697722, year = {2019}, author = {Brunetti, G and Navazio, AS and Giuliani, A and Giordano, A and Proli, EM and Antonelli, G and Raponi, G}, title = {Candida blood stream infections observed between 2011 and 2016 in a large Italian University Hospital: A time-based retrospective analysis on epidemiology, biofilm production, antifungal agents consumption and drug-susceptibility.}, journal = {PloS one}, volume = {14}, number = {11}, pages = {e0224678}, pmid = {31697722}, issn = {1932-6203}, mesh = {Antifungal Agents/pharmacology/*therapeutic use ; Biofilms/drug effects/*growth & development ; Candida/drug effects/isolation & purification/*physiology ; Candidiasis/*blood/drug therapy/*epidemiology/microbiology ; Fluconazole/pharmacology/therapeutic use ; Hospitals, University ; Humans ; Italy/epidemiology ; Microbial Sensitivity Tests ; Principal Component Analysis ; Retrospective Studies ; Time Factors ; }, abstract = {Candida bloodstream infection (BSI) represents a growing infective problem frequently associated to biofilm production due to the utilization of intravascular devices. Candida species distribution (n = 612 strains), their biofilm production and hospital antifungal drug consumption were evaluated in different wards of a tertiary care academic hospital in Italy during the years 2011-2016. In the considered time window, an increasing number of Candida BSI (p = 0.005) and of biofilm producing strains were observed (p<0.0001). Although C. albicans was the species more frequently isolated in BSI with a major biofilm production, an increased involvement of non-albicans species was reported, particularly of C. parapsilosis that displayed a high frequency in catheter infections, and lower biofilm production compared to C. albicans. Although trends of biofilm production were substantially stable in time, a decreasing biofilm production by C. parapsilosis in the Intensive Care Unit (ICU) was observed (p = 0.0041). Principal component analysis displayed a change in antifungal drugs consumption driven by two mutually independent temporal trends, i.e. voriconazole use in the general medicine wards initially, and fluconazole use mainly in the ICU; these factors explain 68.9% and 25.7% of total variance respectively. Moreover, a significant trend (p = 0.003) in fluconazole use during the whole time period considered emerged, particularly in the ICU (p = 0.017), but also in the general medicine wards (p = 0.03). These trends paralleled with significant increase MIC90 of fluconazole (p = 0.05), particularly for C. parapsilosis in the ICU (p = 0.04), with a general and significant decreased trend of the MIC90 values of caspofungin (p = 0.04), and with significant increased MIC50 values for amphotericin B (p = 0.01) over the study period. In conclusion, drug utilization in our hospital turned out to be a putative influencing factor on the ecology of the species, on the increase in time of the biofilm producing strains and on the Candida antifungal susceptibility profile, thus influencing clinical management.}, } @article {pmid31697703, year = {2019}, author = {Booth, WT and Davis, RR and Deora, R and Hollis, T}, title = {Structural mechanism for regulation of DNA binding of BpsR, a Bordetella regulator of biofilm formation, by 6-hydroxynicotinic acid.}, journal = {PloS one}, volume = {14}, number = {11}, pages = {e0223387}, pmid = {31697703}, issn = {1932-6203}, support = {T32 GM095440/GM/NIGMS NIH HHS/United States ; K12 GM102773/GM/NIGMS NIH HHS/United States ; R01 AI075081/AI/NIAID NIH HHS/United States ; R01 AI125560/AI/NIAID NIH HHS/United States ; R21 AI123805/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acids/metabolism ; Bacterial Proteins ; Biofilms/*growth & development ; Bordetella pertussis/metabolism ; DNA/*metabolism ; Niacin/metabolism ; Nicotinic Acids/*metabolism ; Transcription Factors/*genetics/metabolism ; Virulence/physiology ; }, abstract = {Bordetella bacteria are respiratory pathogens of humans, birds, and livestock. Bordetella pertussis the causative agent of whopping cough remains a significant health issue. The transcriptional regulator, BpsR, represses a number of Bordetella genes relating to virulence, cell adhesion, cell motility, and nicotinic acid metabolism. DNA binding of BpsR is allosterically regulated by interaction with 6-hydroxynicotinic acid (6HNA), the first product in the nicotinic acid degradation pathway. To understand the mechanism of this regulation, we have determined the crystal structures of BpsR and BpsR in complex with 6HNA. The structures reveal that BpsR binding of 6HNA induces a conformational change in the protein to prevent DNA binding. We have also identified homologs of BpsR in other Gram negative bacteria in which the amino acids involved in recognition of 6HNA are conserved, suggesting a similar mechanism for regulating nicotinic acid degradation.}, } @article {pmid31695365, year = {2019}, author = {Habibipour, R and Moradi-Haghgou, L and Farmany, A}, title = {Green synthesis of AgNPs@PPE and its Pseudomonas aeruginosa biofilm formation activity compared to pomegranate peel extract.}, journal = {International journal of nanomedicine}, volume = {14}, number = {}, pages = {6891-6899}, pmid = {31695365}, issn = {1178-2013}, mesh = {Animals ; Biofilms/drug effects/*growth & development ; Cell Line ; Cell Survival/drug effects ; Green Chemistry Technology/*methods ; Kinetics ; Metal Nanoparticles/*chemistry/ultrastructure ; Mice ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Pomegranate/*chemistry ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry ; X-Ray Diffraction ; }, abstract = {BACKGROUND: Bacteria are able to form biofilm on the biotic and abiotic surfaces which helps to protect themselves from deleterious conditions, predation, desiccation, and exposure to antibacterial substances. About 80% of bacterial infections are caused by those bacteria living in the biofilm. Pseudomonas aeruginosa, a gram-negative, non-fermentative bacillus, and the ubiquitous bacterium is an important opportunistic pathogen notorious for biofilm formation and is remarkably resistant against most antibiotics multiple front-line antibiotics, which significantly contributes to eradication failure. The aim of this paper was to evaluate the anti-biofilm formation activity of Ag@PPEs gainst P. aeruginosa bacteria.

METHODS: An aqueous extract of black pomegranate peel was used for the synthesis of silver nanoparticles (AgNPs@PPE). The characteristics, anti-biofilm formation and cell toxicity of AgNPs@PPE were examined in vitro.

RESULTS: Absorbance at λmax 372 nm which is related to the surface plasmon resonance, confirms the AgNPs@PPE formation. XRD pattern showed the face-centered qubic (fcc) crystalline structure of AgNPs. TEM images showed that spherical AgNPs size is ranged between 32 and 85 nm. The AgNPs@PPE showed inhibition effect against P. aeruginosa biofilm formation at 0.1 to 0.5 mg/ml concentrations. Cell toxicity assay showed that at 400 µg/ml, AgNPs@PPE were safe without a significant toxicity in L929 cell line.

CONCLUSION: These data indicate that co-treatment of PPE and AgNPs@PPE significantly decreased the biofilm formation rate. Furthermore, no significant toxicity of AgNPs@PPE was shown against L929 cell line at 400 µg/ml concentration.}, } @article {pmid31694193, year = {2019}, author = {Alonso-Calleja, C and Gómez-Fernández, S and Carballo, J and Capita, R}, title = {Prevalence, Molecular Typing, and Determination of the Biofilm-Forming Ability of Listeria monocytogenes Serotypes from Poultry Meat and Poultry Preparations in Spain.}, journal = {Microorganisms}, volume = {7}, number = {11}, pages = {}, pmid = {31694193}, issn = {2076-2607}, support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; }, abstract = {A study was undertaken of the presence of Listeria monocytogenes in 260 samples of poultry meat obtained from retail outlets in northwestern Spain. L. monocytogenes was detected in 20 samples (7.7%). Twenty strains (one strain per positive sample) were characterized. The strains belonged to 10 serotypes: 1/2a (2 strains), 1/2b (2), 1/2c (2), 3a (1), 3b (2), 3c (2), 4a (2), 4b (4), 4c (1), and 4d (2). Cluster analysis (ribotyping; EcoRI) showed a strong genetic relationship between strains isolated from samples coming from different outlets. Ribotyping permitted some isolates of the same serotype to be differentiated, which points to the possible usefulness of this technique in the epidemiological surveillance of L. monocytogenes. All strains formed biofilm on polystyrene, as shown by confocal laser scanning microscopy. The biovolume (between 621.7 ± 36.0 µm[3] and 62,984.0 ± 14,888.2 µm[3] in the observational field of 14,161 μm[2]), percentage of surface coverage (from 2.17 ± 0.84% to 94.43 ± 3.97%), roughness (between 0.399 ± 0.052 and 0.830 ± 0.022), and maximum thickness (between 9.00 ± 0.00 µm and 24.00 ± 14.93 µm) of biofilms varied between strains (p < 0.05). These results expand knowledge of the characteristics of L. monocytogenes isolates from poultry.}, } @article {pmid31693234, year = {2020}, author = {Davis, RT and Brown, PD}, title = {spoT-mediated stringent response influences environmental and nutritional stress tolerance, biofilm formation and antimicrobial resistance in Klebsiella pneumoniae.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {128}, number = {1}, pages = {48-60}, doi = {10.1111/apm.13006}, pmid = {31693234}, issn = {1600-0463}, support = {//University of the West Indies/ ; }, mesh = {Amino Acids/chemistry ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Drug Resistance, Bacterial ; Ethanol/pharmacology ; Gene Expression Regulation, Bacterial ; Glucose/chemistry ; Humans ; Klebsiella pneumoniae/drug effects/*genetics/*physiology ; Phosphates/chemistry ; Sodium Chloride/pharmacology ; *Stress, Physiological ; Virulence/genetics ; Virulence Factors ; }, abstract = {Klebsiella pneumoniae is an important opportunistic pathogen with significant potential for virulence and multidrug resistance. Treatment failure often occurs because the pathogen may couple virulence and drug resistance with the stringent response. This study assessed the role of the spoT gene in environmental and nutritional stress tolerance, exopolysaccharide capsule production and biofilm formation. spoT mutants were constructed using the lambda red recombinase technique, and mutant and wild-type (WT) strains were exposed to limiting concentrations of carbon (glucose), phosphate and aminoacid, and environmental stresses of ethanol, salt and heat. Cell viability, capsule production and cell length were assessed as well as the ability to grow biofilm under antibiotic pressure using gentamicin and ceftazidime. spoT mutants were more susceptible to stresses versus WT; the reverse was true for survival during biofilm susceptibility assay (p < 0.05), especially when carbon and phosphate were present. spoT mutants were elongated and lacked a capsule versus WT and non-starved strains. The inability to produce capsule in mutants before and after starvation was likely a general effect of spoT mutation. These data suggest that the spoT-mediated stringent response is important for K. pneumoniae in conditions of nutrient limitation, environmental stress and antimicrobial pressure.}, } @article {pmid31692081, year = {2020}, author = {Tomizawa, T and Ishikawa, M and Bello-Irizarry, SN and de Mesy Bentley, KL and Ito, H and Kates, SL and Daiss, JL and Beck, C and Matsuda, S and Schwarz, EM and Nishitani, K}, title = {Biofilm Producing Staphylococcus epidermidis (RP62A Strain) Inhibits Osseous Integration Without Osteolysis and Histopathology in a Murine Septic Implant Model.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {38}, number = {4}, pages = {852-860}, pmid = {31692081}, issn = {1554-527X}, support = {P30 AR069655/AR/NIAMS NIH HHS/United States ; P50 AR072000/AR/NIAMS NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Female ; *Host-Pathogen Interactions ; Mice, Inbred BALB C ; *Osseointegration ; Prosthesis-Related Infections/*microbiology/pathology ; Species Specificity ; Staphylococcus epidermidis/*physiology ; Tibia/microbiology/ultrastructure ; }, abstract = {Despite its presence in orthopaedic infections, Staphylococcus epidermidis's ability to directly induce inflammation and bone destruction is unknown. Thus, we compared a clinical strain of methicillin-resistant biofilm-producing S. epidermidis (RP62A) to a highly virulent and osteolytic strain of methicillin-resistant Staphylococcus aureus (USA300) in an established murine implant-associated osteomyelitis model. Bacterial burden was assessed by colony forming units (CFUs), tissue damage was assessed by histology and micro-computed tomography, biofilm was assessed by scanning electron microscopy (SEM), host gene expression was assessed by quantitative polymerase chain reaction, and osseous integration was assessed via biomechanical push-out test. While CFUs were recovered from RP62A-contaminated implants and surrounding tissues after 14 days, the bacterial burden was significantly less than USA300-infected tibiae (p < 0.001). In addition, RP62A failed to produce any of the gross pathologies induced by USA300 (osteolysis, reactive bone formation, Staphylococcus abscess communities, marrow necrosis, and biofilm). However, fibrous tissue was present at the implant-host interface, and rigorous SEM confirmed the rare presence of cocci on RP62A-contaminated implants. Gene expression studies revealed that IL-1β, IL-6, RANKL, and TLR-2 mRNA levels in RP62A-infected bone were increased versus Sterile controls. Ex vivo push-out testing showed that RP62A-infected implants required significantly less force compared with the Sterile group (7.5 ± 3.4 vs. 17.3 ± 4.1 N; p < 0.001), but required 10-fold greater force than USA300-infected implants (0.7 ± 0.3 N; p < 0.001). Taken together, these findings demonstrate that S. epidermidis is a commensal pathogen whose mechanisms to inhibit osseous integration are limited to minimal biofilm formation on the implant, and low-grade inflammation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:852-860, 2020.}, } @article {pmid31691922, year = {2020}, author = {Majumdar, M and Misra, TK and Roy, DN}, title = {In vitro anti-biofilm activity of 14-deoxy-11,12-didehydroandrographolide from Andrographis paniculata against Pseudomonas aeruginosa.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {51}, number = {1}, pages = {15-27}, pmid = {31691922}, issn = {1678-4405}, support = {YSS/2015/001965//Department of Science and Technology, Govt of India/ ; }, mesh = {Andrographis/*chemistry ; Anti-Bacterial Agents/*pharmacology ; Azithromycin/pharmacology ; Biofilms/*drug effects ; Diterpenes/*pharmacology ; Gentamicins/pharmacology ; Microbial Sensitivity Tests ; Plants, Medicinal/chemistry ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects ; }, abstract = {14-Deoxy-11,12-didehydroandrographolide is a biologically active molecule present in the extract of Andrographis paniculata (Kalmegh), a classic ethnic herbal formula, which has been used for over thousand years as therapeutics to treat numerous infectious diseases like upper respiratory tract infection, urinary tract infection, and many more health issues. The present study is designed to ascertain an inhibitor against biofilm formation from the major metabolites of Andrographis paniculata, because the extract of this herb shows inhibition of bacterial quorum sensing (QS) communication and biofilm development against microorganisms. 14-Deoxy-11,12-didehydroandrographolide at 0.1 mM (sub-MIC dose) with azithromycin (6 μg/mL, sub-MIC) or gentamicin (4 μg/mL, sub-MIC) synergistically inhibits 92% biofilm production by a 48-h treatment against Pseudomonas aeruginosa. Further investigation carried out by atomic force microscopy shows promising reduction in roughness and height of biofilm in the presence of 14-deoxy-11,12-didehydroandrographolide compared with the control group. The content of extracellular polymeric substances, level of pyocyanin production, and synthesis of extracellular protease by P. aeruginosa have also been reduced significantly at around 90% in 14-deoxy-11,12-didehydroandrographolide-treated group. In conclusion, 14-deoxy-11,12-didehydroandrographolide could be used as a drug molecule against biofilm development by inhibiting QS pathway in Pseudomonas aeruginosa.}, } @article {pmid31690794, year = {2019}, author = {Brahma, U and Sharma, P and Murthy, S and Sharma, S and Chakraborty, S and Appalaraju, SN and Bhandari, V}, title = {Decreased expression of femXAB genes and fnbp mediated biofilm pathways in OS-MRSA clinical isolates.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {16028}, pmid = {31690794}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Down-Regulation ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/isolation & purification/physiology ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Phenotype ; Staphylococcal Infections/microbiology/pathology ; Staphylococcus aureus/drug effects/genetics/isolation & purification/physiology ; }, abstract = {Methicillin-Resistant Staphylococcus aureus (MRSA) is a significant threat to human health. Additionally, biofilm forming bacteria becomes more tolerant to antibiotics and act as bacterial reservoir leading to chronic infection. In this study, we characterised the antibiotic susceptibility, biofilm production and sequence types (ST) of 74 randomly selected clinical isolates of S. aureus causing ocular infections. Antibiotic susceptibility revealed 74% of the isolates as resistant against one or two antibiotics, followed by 16% multidrug-resistant isolates (MDR), and 10% sensitive. The isolates were characterized as MRSA (n = 15), Methicillin-sensitive S. aureus (MSSA, n = 48) and oxacillin susceptible mecA positive S. aureus (OS-MRSA, n = 11) based on oxacillin susceptibility, mecA gene PCR and PBP2a agglutination test. All OS-MRSA would have been misclassified as MSSA on the basis of susceptibility test. Therefore, both phenotypic and genotypic tests should be included to prevent strain misrepresentation. In addition, in-depth studies for understanding the emerging OS-MRSA phenotype is required. The role of fem XAB gene family has been earlier reported in OS-MRSA phenotype. Sequence analysis of the fem XAB genes revealed mutations in fem × (K3R, H11N, N18H and I51V) and fem B (L410F) genes. The fem XAB genes were also found down-regulated in OS-MRSA isolates in comparison to MRSA. In OS-MRSA isolates, biofilm formation is regulated by fibronectin binding proteins A & B. Molecular typing of the isolates revealed genetic diversity. All the isolates produced biofilm, however, MRSA isolates with strong biofilm phenotype represent a worrisome situation and may even result in treatment failure.}, } @article {pmid31689511, year = {2020}, author = {Demir, C and Demirci, M and Yigin, A and Tokman, HB and Cetik Yildiz, S}, title = {Presence of biofilm and adhesin genes in Staphylococcus aureus strains taken from chronic wound infections and their genotypic and phenotypic antimicrobial sensitivity patterns.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {29}, number = {}, pages = {101584}, doi = {10.1016/j.pdpdt.2019.101584}, pmid = {31689511}, issn = {1873-1597}, mesh = {Adhesins, Bacterial/drug effects/*genetics ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Bacterial Proteins/genetics ; Bacteriological Techniques ; Biofilms/*drug effects ; Chronic Disease ; Dose-Response Relationship, Drug ; Drug Resistance, Bacterial/drug effects/*genetics ; Genotype ; Humans ; Phenotype ; Staphylococcus aureus/drug effects/*genetics ; Turkey ; Wound Infection/*microbiology ; }, abstract = {The purpose of this research was to examine biofilm (icaA, icaD and bap) and adhesin (clfA, fnbA, cna) genes, and also assess the genotypic and phenotypic antimicrobial resistance patterns of Staphylococcus aureus strains taken from wound specimens in Mardin, Turkey. A total of 220 wound specimens were investigated. The biofilm forming ability and resistance pattern for eleven antimicrobial agents were investigated by conventional and multiplex PCR methods. S. aureus were taken from 112 (50.9%) of 220 wound specimens. Moreover, biofilm production was found in 79 (70.5%) of the 112 S. aureus isolates. 97 (86.6%) strains of all isolates were positive for icaA and icaD, and 15 (13.4%) for bap. The adhesin genes, cna, fnbA and clfA were detected in 98 (87.5%), 87 (77.7%), and 75 (66.9%) strains, respectively. The numbers of MSSA and MRSA bearing antimicrobial resistance genes were 19 (16.96%) and 32 (28.57%) for blaZ, 9 (8.04%) and 17 (15.18%) for tetK, 6 (5.36%) and 14 (12.5%) for ermC, 2 (1.79%) and 7 (6.25%) for tetM, 0 (0%) and 5 (4.46%) for mecA, 2 (1.79%) and 4 (3.57%) for ermA, 1 (0.89%) and 2 (1.79%) for both tetK and tetM, respectively. Our findings indicate that multiplex PCR is a suitable way for identifying biofilm and adhesin producing S. aureus. Our data also provided a country-wide oversight of the S. aureus antimicrobial resistance gene profiles for the properly therapy of patients and to control the spreading of the resistance genes.}, } @article {pmid31687841, year = {2019}, author = {Wang, T and Flint, S and Palmer, J}, title = {Magnesium and calcium ions: roles in bacterial cell attachment and biofilm structure maturation.}, journal = {Biofouling}, volume = {35}, number = {9}, pages = {959-974}, doi = {10.1080/08927014.2019.1674811}, pmid = {31687841}, issn = {1029-2454}, mesh = {Bacteria/*drug effects/genetics/metabolism ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; Calcium/*pharmacology ; Calcium-Binding Proteins/metabolism ; Cations, Divalent ; Gene Expression Regulation, Bacterial/drug effects ; Magnesium/*pharmacology ; }, abstract = {The ubiquitous divalent cations magnesium and calcium are important nutrients required by bacteria for growth and cell maintenance. Multi-faceted roles are shown both in bacterial initial attachment and biofilm maturation. The effects of calcium and magnesium can be highlighted in physio-chemical interactions, gene regulation and bio-macromolecular structural modification, which lead to either promotion or inhibition of biofilms. This review outlines recent research addressing phenotypic changes and mechanisms undertaken by calcium and magnesium in affecting bacterial biofilm formation.}, } @article {pmid31686691, year = {2019}, author = {Lauer Cruz, K and de Souza da Motta, A}, title = {Characterization of biofilm production by Pseudomonas fluorescens isolated from refrigerated raw buffalo milk.}, journal = {Journal of food science and technology}, volume = {56}, number = {10}, pages = {4595-4604}, pmid = {31686691}, issn = {0022-1155}, abstract = {Pseudomonas fluorescens can often be isolated from refrigerated raw milk. Two strains of P. fluorescens PL5.4 and PL7.1, isolated from raw buffalo milk, were evaluated for their proteolytic capacity, exopolysaccharide production and biofilm production. Proteolytic activity was observed in both strains. The P. fluorescens PL5.4 strain presented fluorescence in the presence of calcofluor, indicating exopolysaccharide production. Both strains were able to produce biofilm at 7 °C for 72 h. For the biofilm production test on stainless steel, adherent cell counts of up to 7.1, 7.3 and 8.8 log CFU/cm[2] at 7, 23 and 30 °C were obtained. Through scanning electron microscopy, it was possible to observe the biofilm produced by the P. fluorescens PL5.4 strain. Proper cleaning and disinfection practices in order are important to reduce bacterial contamination and extend the useful life of raw material and its derivatives.}, } @article {pmid31686149, year = {2019}, author = {Yi, J and Zhang, D and Cheng, Y and Tan, J and Luo, Y}, title = {The impact of Paenibacillus polymyxa HY96-2 luxS on biofilm formation and control of tomato bacterial wilt.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {23-24}, pages = {9643-9657}, pmid = {31686149}, issn = {1432-0614}, support = {2017YFD0201107-2-3//the National Key Research and Development Program of China/ ; 31501693//the National Natural Science Fund/ ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Biological Control Agents ; Carbon-Sulfur Lyases/*genetics ; Gene Expression Regulation, Bacterial ; Solanum lycopersicum/*microbiology ; Paenibacillus polymyxa/genetics/*physiology ; Plant Diseases/microbiology/*prevention & control ; Quorum Sensing ; Ralstonia solanacearum/*pathogenicity ; }, abstract = {The focus of this study was to investigate the effects of luxS, a key regulatory gene of the autoinducer-2 (AI-2) quorum sensing (QS) system, on the biofilm formation and biocontrol efficacy against Ralstonia solanacearum by Paenibacillus polymyxa HY96-2. luxS mutants were constructed and assayed for biofilm formation of the wild-type (WT) strain and luxS mutants of P. polymyxa HY96-2 in vitro and in vivo. The results showed that luxS positively regulated the biofilm formation of HY96-2. Greenhouse experiments of tomato bacterial wilt found that from the early stage to late stage postinoculation, the biocontrol efficacy of the luxS deletion strain was the lowest with 50.70 ± 1.39% in the late stage. However, the luxS overexpression strain had the highest biocontrol efficacy with 75.66 ± 1.94% in the late stage. The complementation of luxS could restore the biocontrol efficacy of the luxS deletion strain with 69.84 ± 1.09% in the late stage, which was higher than that of the WT strain with 65.94 ± 2.73%. Therefore, we deduced that luxS could promote the biofilm formation of P. polymyxa HY96-2 and further promoted its biocontrol efficacy against R. solanacearum.}, } @article {pmid31685917, year = {2019}, author = {Noirot-Gros, MF and Forrester, S and Malato, G and Larsen, PE and Noirot, P}, title = {CRISPR interference to interrogate genes that control biofilm formation in Pseudomonas fluorescens.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {15954}, pmid = {31685917}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; CRISPR-Cas Systems ; *Clustered Regularly Interspaced Short Palindromic Repeats ; Cytokinesis/genetics ; Gene Editing ; *Gene Expression Regulation, Bacterial ; Gene Silencing ; Pseudomonas fluorescens/*genetics/*growth & development/metabolism ; }, abstract = {Bacterial biofilm formation involves signaling and regulatory pathways that control the transition from motile to sessile lifestyle, production of extracellular polymeric matrix, and maturation of the biofilm 3D structure. Biofilms are extensively studied because of their importance in biomedical, ecological and industrial settings. Gene inactivation is a powerful approach for functional studies but it is often labor intensive, limiting systematic gene surveys to the most tractable bacterial hosts. Here, we adapted the CRISPR interference (CRISPRi) system for use in diverse strain isolates of P. fluorescens, SBW25, WH6 and Pf0-1. We found that CRISPRi is applicable to study complex phenotypes such as cell morphology, motility and biofilm formation over extended periods of time. In SBW25, CRISPRi-mediated silencing of genes encoding the GacA/S two-component system and regulatory proteins associated with the cylic di-GMP signaling messenger produced swarming and biofilm phenotypes similar to those obtained after gene inactivation. Combined with detailed confocal microscopy of biofilms, our study also revealed novel phenotypes associated with extracellular matrix biosynthesis as well as the potent inhibition of SBW25 biofilm formation mediated by the PFLU1114 operon. We conclude that CRISPRi is a reliable and scalable approach to investigate gene networks in the diverse P. fluorescens group.}, } @article {pmid31685418, year = {2020}, author = {Adnan, M and Ali Shah, MR and Jamal, M and Jalil, F and Andleeb, S and Nawaz, MA and Pervez, S and Hussain, T and Shah, I and Imran, M and Kamil, A}, title = {Isolation and characterization of bacteriophage to control multidrug-resistant Pseudomonas aeruginosa planktonic cells and biofilm.}, journal = {Biologicals : journal of the International Association of Biological Standardization}, volume = {63}, number = {}, pages = {89-96}, doi = {10.1016/j.biologicals.2019.10.003}, pmid = {31685418}, issn = {1095-8320}, mesh = {Biofilms/*growth & development ; *Drug Resistance, Multiple, Bacterial ; Pseudomonas Phages/*metabolism ; Pseudomonas aeruginosa/*physiology/*virology ; }, abstract = {Pseudomonas aeruginosa is Gram-negative bacterium, one of the leading cause of drug-resistant nosocomial infections in developing countries. This bacterium possesses chromosomally encoded efflux pumps, poor permeability of outer-membrane and high tendency for biofilm formation which are tools to confer resistance. Bacteriophages are regarded as feasible treatment option for control of resistant P. aeruginosa. The aim of the current study was isolate and characterized a bacteriophage against P. aeruginosa with MDR and biofilm ability. A bacteriophage MA-1 with moderate host range was isolated from waste water. The phage was considerable heat and pH stable. Electron microscopy revealed that phage MA-1 belongs to Myoviridae family. Its genome was dsDNA (≈50 kb), coding for eighteen different proteins (ranging from 12 to 250 KDa). P. aeruginosa-2949 log growth phase was significantly reduced by phage MA-1 (2.5 × 10[3] CFU/ml) as compared to control (without phage). Phage MA-1 also showed significant reductions of 2.0, 2.5 and 3.2 folds in 24, 48, and 74 h old biofilms after 6 h treatment with phage respectively as compared to control. It was concluded from this study that phage MA-1 has capability of killing P. aeruginosa planktonic cells and biofilm, but for complete eradication cocktail will more effective to avoid resistance.}, } @article {pmid31685050, year = {2020}, author = {Ribeiro, MM and Graziano, KU and Olson, N and França, R and Alfa, MJ}, title = {The polytetrafluoroethylene (PTFE) channel model of cyclic-buildup biofilm and traditional biofilm: The impact of friction, and detergent on cleaning and subsequent high-level disinfection.}, journal = {Infection control and hospital epidemiology}, volume = {41}, number = {2}, pages = {172-180}, doi = {10.1017/ice.2019.306}, pmid = {31685050}, issn = {1559-6834}, mesh = {*Biofilms ; Colony Count, Microbial ; Detergents ; *Disinfectants ; Disinfection/*methods ; Endoscopes ; Enterococcus faecalis/*growth & development/isolation & purification ; Equipment Contamination ; Friction ; Glutaral ; Microbial Viability ; Microscopy, Electron, Scanning ; *Polytetrafluoroethylene ; Pseudomonas aeruginosa/*growth & development/isolation & purification ; }, abstract = {OBJECTIVE: To evaluate the efficacy of detergent and friction on removal of traditional biofilm and cyclic-buildup biofilm (CBB) from polytetrafluoroethylene (PTFE) channels and to evaluate the efficacy of glutaraldehyde to kill residual bacteria after cleaning.

METHODS: PTFE channels were exposed to artificial test soil containing 108 CFU/mL of Pseudomonas aeruginosa and Enterococcus faecalis, followed by full cleaning and high-level disinfection (HLD) for five repeated rounds to establish CBB. For traditional biofilm, the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush, and Pull Thru channel cleaner were compared to a water flush only. Carbohydrate, protein, viable count, adenosine triphosphate (ATP) levels were analyzed and atomic force microscopy (AFM) was performed.

RESULTS: In the absence of friction, cleaning of traditional biofilm and CBB was not effective compared to the positive control (Dunn-Bonferroni tests; P > .05) regardless of the detergent used. ATP, protein, and carbohydrate analyses were unable to detect traditional biofilm or CBB. The AFM analysis showed that fixation resulted in CBB being smoother and more compact than traditional biofilm.

CONCLUSION: Friction during the cleaning process was a critical parameter regardless of the detergent used for removal of either traditional biofilm or CBB. Glutaraldehyde effectively killed the remaining microorganisms regardless of the cleaning method used.}, } @article {pmid31684101, year = {2019}, author = {Lade, H and Park, JH and Chung, SH and Kim, IH and Kim, JM and Joo, HS and Kim, JS}, title = {Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media.}, journal = {Journal of clinical medicine}, volume = {8}, number = {11}, pages = {}, pmid = {31684101}, issn = {2077-0383}, support = {2017M3A9E4077232//National Research Foundation of Korea/ ; }, abstract = {Staphylococcus aureus (S. aureus) causes persistent biofilm-related infections. Biofilm formation by S. aureus is affected by the culture conditions and is associated with certain genotypic characteristics. Here, we show that glucose and sodium chloride (NaCl) supplementation of culture media, a common practice in studies of biofilms in vitro, influences both biofilm formation by 40 S. aureus clinical isolates (methicillin-resistant and methicillin-sensitive S. aureus) and causes variations in biofilm quantification. Methicillin-resistant strains formed more robust biofilms than methicillin-sensitive strains in tryptic soy broth (TSB). However, glucose supplementation in TSB greatly promoted and stabilized biofilm formation of all strains, while additional NaCl was less efficient in this respect and resulted in significant variation in biofilm measurements. In addition, we observed that the ST239-SCCmec (Staphylococcal Cassette Chromosome mec) type III lineage formed strong biofilms in TSB supplemented with glucose and NaCl. Links between biofilm formation and accessory gene regulator (agr) status, as assessed by δ-toxin production, and with mannitol fermentation were not found. Our results show that TSB supplemented with 1.0% glucose supports robust biofilm production and reproducible quantification of S. aureus biofilm formation in vitro, whereas additional NaCl results in major variations in measurements of biofilm formation.}, } @article {pmid31683828, year = {2019}, author = {Guimerà, X and Moya, A and Dorado, AD and Illa, X and Villa, R and Gabriel, D and Gamisans, X and Gabriel, G}, title = {A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling.}, journal = {Sensors (Basel, Switzerland)}, volume = {19}, number = {21}, pages = {}, pmid = {31683828}, issn = {1424-8220}, support = {CTQ2015-69802-C2-1-R//Ministerio de Ciencia y Tecnología/ ; }, mesh = {*Biofilms ; Electrochemistry/*instrumentation ; Electroplating ; *Equipment Design ; Hydrogen-Ion Concentration ; Microelectrodes ; Oxygen/*analysis ; Platinum/chemistry ; Reproducibility of Results ; Solubility ; }, abstract = {A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton[®]) film of 127 µm as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion[®] layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0-8 mg L[-1], a detection limit of 0.05 mg L[-1], and a sensitivity of 2.06 nA L mg[-1]. pH electrodes showed a linear super-Nernstian response (74.2 ± 0.7 mV/pH unit) in a wide pH range (pH 4-9). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.}, } @article {pmid31682418, year = {2019}, author = {Nisbett, LM and Binnenkade, L and Bacon, B and Hossain, S and Kotloski, NJ and Brutinel, ED and Hartmann, R and Drescher, K and Arora, DP and Muralidharan, S and Thormann, KM and Gralnick, JA and Boon, EM}, title = {NosP Signaling Modulates the NO/H-NOX-Mediated Multicomponent c-Di-GMP Network and Biofilm Formation in Shewanella oneidensis.}, journal = {Biochemistry}, volume = {58}, number = {48}, pages = {4827-4841}, pmid = {31682418}, issn = {1520-4995}, support = {R01 GM118894/GM/NIGMS NIH HHS/United States ; T32 GM092714/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Heme/metabolism ; Nitric Oxide/*metabolism ; Shewanella/genetics/*physiology ; Signal Transduction ; }, abstract = {Biofilms form when bacteria aggregate in a self-secreted exopolysaccharide matrix; they are resistant to antibiotics and implicated in disease. Nitric oxide (NO) is known to mediate biofilm formation in many bacteria via ligation to H-NOX (heme-NO/oxygen binding) domains. Most NO-responsive bacteria, however, lack H-NOX domain-containing proteins. We have identified another NO-sensing protein (NosP), which is predicted to be involved in two-component signaling and biofilm regulation in many species. Here, we demonstrate that NosP participates in the previously described H-NOX/NO-responsive multicomponent c-di-GMP signaling network in Shewanella oneidensis. Strains lacking either nosP or its co-cistronic kinase nahK (previously hnoS) produce immature biofilms, while hnoX and hnoK (kinase responsive to NO/H-NOX) mutants result in wild-type biofilm architecture. We demonstrate that NosP regulates the autophosphorylation activity of NahK as well as HnoK. HnoK and NahK have been shown to regulate three response regulators (HnoB, HnoC, and HnoD) that together comprise a NO-responsive multicomponent c-di-GMP signaling network. Here, we propose that NosP/NahK adds regulation on top of H-NOX/HnoK to modulate this c-di-GMP signaling network, and ultimately biofilm formation, by governing the flux of phosphate through both HnoK and NahK. In addition, it appears that NosP and H-NOX act to counter each other in a push-pull mechanism; NosP/NahK promotes biofilm formation through inhibition of H-NOX/HnoK signaling, which itself reduces the extent of biofilm formation. Addition of NO results in a reduction of c-di-GMP and biofilm formation, primarily through disinhibition of HnoK activity.}, } @article {pmid31681870, year = {2019}, author = {Kumari, P and Arora, N and Chatrath, A and Gangwar, R and Pruthi, V and Poluri, KM and Prasad, R}, title = {Delineating the Biofilm Inhibition Mechanisms of Phenolic and Aldehydic Terpenes against Cryptococcus neoformans.}, journal = {ACS omega}, volume = {4}, number = {18}, pages = {17634-17648}, pmid = {31681870}, issn = {2470-1343}, abstract = {The recalcitrant biofilm formed by fungus Cryptococcus neoformans is a life-threatening pathogenic condition responsible for further intensifying cryptococcosis. Considering the enhanced biofilm resistance and toxicity of synthetic antifungal drugs, the search for efficient, nontoxic, and cost-effective natural therapeutics has received a major boost. Phenolic (thymol and carvacrol) and aldehydic (citral) terpenes are natural and safe alternatives capable of efficient microbial biofilm inhibition. However, the biofilm inhibition mechanism of these terpenes still remains unclear. In this study, we adopted an integrative biophysical and biochemical approach to elucidate the hierarchy of their action against C. neoformans biofilm cells. The microscopic analysis revealed disruption of the biofilm cell surface with elevation in surface roughness and reduction in cell height. Although all terpenes acted through ergosterol biosynthesis inhibition, the phenolic terpenes also selectively interacted via ergosterol binding. Further, the alterations in the fatty acid profile in response to terpenes attenuated the cell membrane fluidity with enhanced permeability, resulting in pore formation and efflux of the K[+]/intracellular content. Additionally, mitochondrial depolarization caused higher levels of reactive oxygen species, which led to increased lipid peroxidation and activation of the antioxidant defense system. Indeed, the oxidative stress caused a significant decline in the amount of extracellular polymeric matrix and capsule sugars (mannose, xylose, and glucuronic acid), leading to a reduced capsule size and an overall negative charge on the cell surface. This comprehensive data revealed the mechanistic insights into the mode of action of terpenes on biofilm inhibition, which could be exploited for formulating novel anti-biofilm agents.}, } @article {pmid31681633, year = {2019}, author = {Swetha, TK and Pooranachithra, M and Subramenium, GA and Divya, V and Balamurugan, K and Pandian, SK}, title = {Umbelliferone Impedes Biofilm Formation and Virulence of Methicillin-Resistant Staphylococcus epidermidis via Impairment of Initial Attachment and Intercellular Adhesion.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {357}, pmid = {31681633}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Energy Metabolism/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*physiology ; Microbial Sensitivity Tests ; Staphylococcal Infections/*microbiology ; Umbelliferones/*pharmacology ; Virulence/drug effects ; Virulence Factors ; }, abstract = {Staphylococcus epidermidis is an opportunistic human pathogen, which is involved in numerous nosocomial and implant associated infections. Biofilm formation is one of the prime virulence factors of S. epidermidis that supports its colonization on biotic and abiotic surfaces. The global dissemination of three lineages of S. epidermidis superbugs highlights its clinical significance and the imperative need to combat its pathogenicity. Thus, in the current study, the antibiofilm activity of umbelliferone (UMB), a natural product of the coumarin family, was assessed against methicillin-resistant S. epidermidis (MRSE). UMB exhibited significant antibiofilm activity (83%) at 500 μg/ml concentration without growth alteration. Microscopic analysis corroborated the antibiofilm potential of UMB and unveiled its potential to impair intercellular adhesion, which was reflected in auto-aggregation and solid phase adherence assays. Furthermore, real time PCR analysis revealed the reduced expression of adhesion encoding genes (icaD, atlE, aap, bhp, ebh, sdrG, and sdrF). Down regulation of agrA and reduced production of secreted hydrolases upon UMB treatment were speculated to hinder invasive lifestyle of MRSE. Additionally, UMB hindered slime synthesis and biofilm matrix components, which were believed to augment antibiotic susceptibility. In vivo assays using Caenorhabditis elegans divulged the non-toxic nature of UMB and validated the antibiofilm, antivirulence, and antiadherence properties of UMB observed in in vitro assays. Thus, UMB impairs MRSE biofilm by turning down the initial attachment and intercellular adhesion. Altogether, the obtained results suggest the potent antibiofilm activity of UMB and the feasibility of using it in clinical settings for combating S. epidermidis infections.}, } @article {pmid31680469, year = {2020}, author = {Nakagami, G and Schultz, G and Kitamura, A and Minematsu, T and Akamata, K and Suga, H and Kurita, M and Hayashi, C and Sanada, H}, title = {Rapid detection of biofilm by wound blotting following sharp debridement of chronic pressure ulcers predicts wound healing: A preliminary study.}, journal = {International wound journal}, volume = {17}, number = {1}, pages = {191-196}, pmid = {31680469}, issn = {1742-481X}, support = {17H04455//Japan Society for the Promotion of Science/ ; }, mesh = {Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Bacterial Infections/diagnosis/*drug therapy ; Biofilms/*drug effects ; Debridement/methods ; Female ; Humans ; Japan ; Male ; Middle Aged ; Pressure Ulcer/*diagnosis/*drug therapy/microbiology ; Retrospective Studies ; Surgical Wound Infection/*drug therapy ; Treatment Outcome ; Wound Healing/*drug effects ; }, abstract = {For optimal wound bed preparation, wound debridement is essential to eliminate bacterial biofilms. However, it is challenging for clinicians to determine whether the biofilm is completely removed. A newly developed biofilm detection method based on wound blotting technology may be useful. Thus, we aimed to investigate the effect of biofilm elimination on wound area decrease in pressure ulcers, as confirmed using the wound blotting method. In this retrospective observational study, we enrolled patients with pressure ulcers who underwent sharp debridement with pre- and post-debridement wound blotting. Biofilm was detected on the nitrocellulose membrane using ruthenium red or alcian blue staining. Patients were included if the test was positive for biofilm before wound debridement. Percent decrease in wound area after 1 week was calculated as an outcome measure. We classified the wounds into a biofilm-eliminated group and a biofilm-remaining group based on the post-debridement wound blotting result. Sixteen wound blotting samples from nine pressure ulcers were collected. The percent decrease in wound area was significantly higher in the biofilm-eliminated group (median: 14.4%, interquartile range: 4.6%-20.1%) than in the biofilm-remaining group (median: -14.5%, interquartile range: -25.3%-9.6%; P = .040). The presence of remaining biofilms was an independent predictor for reduced percent decrease in wound area (coefficient = -22.84, P = .040). Biofilm-based wound care guided by wound blotting is a promising measure to help clinicians eliminate bacterial bioburden more effectively for wound area reduction.}, } @article {pmid31680421, year = {2019}, author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M}, title = {Interspecies interactions reduce selection for a biofilm-optimized variant in a four-species biofilm model.}, journal = {Environmental microbiology reports}, volume = {11}, number = {6}, pages = {835-839}, doi = {10.1111/1758-2229.12803}, pmid = {31680421}, issn = {1758-2229}, support = {BK20190703//Natural Science Foundation of Jiangsu Province, China/ ; 19KJB530010//Natural Science Foundation of the Higher Education Instructions of Jiangsu Province, China/ ; R250-2017-1392//Lundbeckfonden/ ; NNF17OC0027620//Novo Nordisk Foundation/ ; 10098//Villum Fonden/ ; }, mesh = {Bacteria/*growth & development ; Biofilms/*growth & development ; *Microbial Consortia ; *Microbial Interactions ; *Selection, Genetic ; }, abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here, we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes.}, } @article {pmid31679132, year = {2019}, author = {Gabriel, C and Grenho, L and Cerqueira, F and Medeiros, R and Dias, AM and Ribeiro, AI and Proença, MF and Fernandes, MH and Sousa, JC and Monteiro, FJ and Ferraz, MP}, title = {Inhibitory Effect of 5-Aminoimidazole-4-Carbohydrazonamides Derivatives Against Candida spp. Biofilm on Nanohydroxyapatite Substrate.}, journal = {Mycopathologia}, volume = {184}, number = {6}, pages = {775-786}, pmid = {31679132}, issn = {1573-0832}, support = {PTDC/SAU-BMA/111233/2009//Fundação para a Ciência e a Tecnologia/ ; SFRH/BD/72866/2010//Fundação para a Ciência e a Tecnologia/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biocompatible Materials ; Biofilms/*drug effects/growth & development ; *Candida/drug effects/growth & development ; Candida albicans/drug effects/growth & development ; Cell Line/drug effects ; Humans ; Imidazoles/pharmacology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Osteoblasts/drug effects ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*drug therapy/microbiology ; }, abstract = {Candida can adhere and form biofilm on biomaterials commonly used in medical devices which is a key attribute that enhances its ability to cause infections in humans. Furthermore, biomaterial-related infections represent a major therapeutic challenge since Candida biofilms are implicated in antifungal therapies failure. The goals of the present work were to investigate the effect of three 5-aminoimidazole-4-carbohydrazonamides, namely (Z)-5-amino-1-methyl-N'-aryl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (1a), 4-fluorophenyl (1b), 3-fluorophenyl (1c)], on Candida albicans and Candida krusei biofilm on nanohydroxyapatite substrate, a well-known bioactive ceramic material. To address these goals, both quantitative methods (by cultivable cell numbers) and qualitative evaluation (by scanning electron microscopy) were used. Compounds cytocompatibility towards osteoblast-like cells was also evaluated after 24 h of exposure, through resazurin assay. The three tested compounds displayed a strong inhibitory effect on biofilm development of both Candida species as potent in vitro activity against C. albicans sessile cells. Regarding cytocompatibility, a concentration-dependent effect was observed. Together, these findings indicated that the potent activity of imidazole derivatives on Candida spp. biofilms on nanohydroxyapatite substrate, in particular compound 1c, is worth further investigating.}, } @article {pmid31678888, year = {2020}, author = {Zhang, H and Wang, H and Jie, M and Zhang, K and Qian, Y and Ma, J}, title = {Performance and microbial communities of different biofilm membrane bioreactors with pre-anoxic tanks treating mariculture wastewater.}, journal = {Bioresource technology}, volume = {295}, number = {}, pages = {122302}, doi = {10.1016/j.biortech.2019.122302}, pmid = {31678888}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Membranes, Artificial ; *Microbiota ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The performance of pollutant removals, activated sludge characteristics, and microbial communities of two biofilm membrane bioreactors coupled with pre-anoxic tanks (BF-AO-MBRs) (one using fiber bundle bio-carriers (FB-MBR) and the other using suspended bio-carriers (MB-MBR)) were compared at the salinity between zero and 60 g/L. At all salinities, three bioreactors showed good COD average removal efficiencies (>94.1%), and FB-MBR showed the best TN removal efficiency (90.4% at 30 g/L salinity). Moreover, FB-MBR had the faster process start-up time and better salt shock resistance. At high salinities (30-60 g/L), more extracellular polymeric substances were produced by the BF-AO-MBRs to avoid the penetration of salt and protect the bacterial community. Because of the different attachment patterns of biofilms, the microbial community structure in the FB-MBR exposed to 30 g/L salinity had higher nitrite-oxidizing/ammonia-oxidizing bacteria ratio (6.44) with more abundance of denitrifiers, which contribute to higher TN removal efficiency and lower nitrite accumulation.}, } @article {pmid31678321, year = {2020}, author = {D'Andrea, MM and Frezza, D and Romano, E and Marmo, P and Henrici De Angelis, L and Perini, N and Thaller, MC and Di Lallo, G}, title = {The lytic bacteriophage vB_EfaH_EF1TV, a new member of the Herelleviridae family, disrupts biofilm produced by Enterococcus faecalis clinical strains.}, journal = {Journal of global antimicrobial resistance}, volume = {21}, number = {}, pages = {68-75}, doi = {10.1016/j.jgar.2019.10.019}, pmid = {31678321}, issn = {2213-7173}, mesh = {Bacteriolysis ; Biofilms/*growth & development ; Caudovirales/*physiology ; Enterococcus faecalis/*physiology/ultrastructure/virology ; Genome Size ; Genome, Viral ; High-Throughput Nucleotide Sequencing ; Microscopy, Confocal ; Whole Genome Sequencing/*methods ; }, abstract = {OBJECTIVES: The aim of this study is to characterize a new bacteriophage able to infect Enterococcus faecalis, and to evaluate its ability to disrupt biofilm.

METHODS: The vB_EfaH_EF1TV (EF1TV) host-range was determined by spot test and efficiency of plating using a collection of 15E. faecalis clinical strains. The phage genome was sequenced with a next generation sequencing approach. Anti-biofilm activity was tested by crystal violet method and confocal laser scanning microscopy. Phage-resistant mutants were selected and sequenced to investigate receptors exploited by phage for infection.

RESULTS: EF1TV is a newly discoveredE. faecalis phage which belongs to the Herelleviridae family. EF1TV, whose genome is 98% identical to φEF24C, is characterized by a linear dsDNA genome of 143,507 bp with direct terminal repeats of 1,911 bp. The phage is able to infect E. faecalis and shows also the ability to degrade biofilm produced by strains of this species. The results were confirmed by confocal laser scanning microscopy analyzing the biofilm reduction in the same optical field before and after phage infection.

CONCLUSIONS: The EF1TV phage shows promising features such as an obligatory lytic nature, an anti-biofilm activity and the absence of integration-related proteins, antibiotic resistance determinants and virulence factors, and therefore could be a promising tool for therapeutic applications.}, } @article {pmid31677806, year = {2020}, author = {Rathinam, NK and Gorky, and Bibra, M and Salem, DR and Sani, RK}, title = {Bioelectrochemical approach for enhancing lignocellulose degradation and biofilm formation in Geobacillus strain WSUCF1.}, journal = {Bioresource technology}, volume = {295}, number = {}, pages = {122271}, doi = {10.1016/j.biortech.2019.122271}, pmid = {31677806}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; Cellulose ; *Geobacillus ; Lignin ; Zea mays ; }, abstract = {Investigations on microbial electrocatalysis as a strategy for enhancing the rates of substrate utilization leading to enhanced yield of biomass and enhanced biofilm formation are reported. A thermophilic Geobacillus sp. strain WSUCF1 (60 °C), a potential lignocellulose degrading microorganism was used as the electrocatalyst. Glucose, cellulose, and corn stover were used as the feedstocks. The results of this investigation showed that applying the oxidation potential of -0.383 mV (vs PRE) increased the glucose utilization and COD removal by 25.5% and 29.7% respectively. The bioelectrocatalysis strategy also increased the biomass yield by 81.2, 42.1, and 49.5% in the case of systems fed with glucose, cellulose, and corn stover, respectively, when compared with the systems without applied oxidation potential. This is the first work reporting the effects of applied oxidation potential on increasing the rates of degradation of lignocellulosic biomass and enhanced biofilm formation.}, } @article {pmid31677404, year = {2020}, author = {Li, H and Song, HL and Xu, H and Lu, Y and Zhang, S and Yang, YL and Yang, XL and Lu, YX}, title = {Effect of the coexposure of sulfadiazine, ciprofloxacin and zinc on the fate of antibiotic resistance genes, bacterial communities and functions in three-dimensional biofilm-electrode reactors.}, journal = {Bioresource technology}, volume = {296}, number = {}, pages = {122290}, doi = {10.1016/j.biortech.2019.122290}, pmid = {31677404}, issn = {1873-2976}, mesh = {*Anti-Bacterial Agents ; Bacteria ; Biofilms ; *Ciprofloxacin ; Drug Resistance, Microbial ; Electrodes ; Genes, Bacterial ; Residence Characteristics ; Sulfadiazine ; Wastewater ; Zinc ; }, abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) with high treatment efficiency were constructed to treat wastewater containing sulfadiazine (SDZ) and ciprofloxacin (CIP) coexposure with Zinc (Zn). The results showed that coexposure to target antibiotics and Zn increased the absolute and relative abundances of target antibiotic resistance genes (ARGs). Additionally, the target ARG abundances were higher on cathode of 3D-BER compared with ordinary anaerobic reactor while the abundances of total ARGs were decreased in the effluent. Meanwhile, redundancy analysis results revealed that the composition of bacteria carrying ARGs was greatly influenced in the cathode by the accumulation of Zn and antibiotic, which dominated the changes of ARG abundances. Additionally, ARGs with their host bacteria revealed by network analysis were partially deposited on electrode substrates when being removed from wastewater. Thus, 3D-BER exhibits capability of simultaneously eliminating antibiotic and Zn, and greatly reduces the risks of ARGs spread.}, } @article {pmid31676401, year = {2020}, author = {Kipanga, PN and Liu, M and Panda, SK and Mai, AH and Veryser, C and Van Puyvelde, L and De Borggraeve, WM and Van Dijck, P and Matasyoh, J and Luyten, W}, title = {Biofilm inhibiting properties of compounds from the leaves of Warburgia ugandensis Sprague subsp ugandensis against Candida and staphylococcal biofilms.}, journal = {Journal of ethnopharmacology}, volume = {248}, number = {}, pages = {112352}, doi = {10.1016/j.jep.2019.112352}, pmid = {31676401}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Antifungal Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development ; *Magnoliopsida/chemistry ; Molecular Structure ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; *Plant Leaves/chemistry ; Staphylococcus/*drug effects/growth & development ; Structure-Activity Relationship ; }, abstract = {Warburgia ugandensis Sprague subspecies ugandensis is a plant widely distributed in Eastern, Central and Southern Africa. In humans, it is used to treat respiratory infections, tooth aches, malaria, skin infections, venereal diseases, diarrhea, fevers and aches.

AIM OF THE STUDY: This study aims to identify the bioactive compounds against clinically important biofilm-forming strains of Candida and staphylococci that are responsible for tissue and implanted device-related infections.

METHODS: Using a bioassay-guided fractionation approach, hexane -, ethanol -, acetone - and water extracts from the leaves of W. ugandensis, their subsequent fractions and isolated compounds were tested against both developing and preformed 24 h-biofilms of Candida albicans SC5314, Candida glabrata BG2, Candida glabrata ATCC 2001, Staphylococcus epidermidis 1457 and Staphylococcus aureus USA 300 using microtiter susceptibility tests. Planktonic cells were also tested in parallel for comparison purposes. Confocal scanning laser microscopy was also used to visualize effects of isolated compounds on biofilm formation.

RESULTS: Warburganal, polygodial and alpha-linolenic acid (ALA) were the major bioactive compounds isolated from the acetone extract of W. ugandensis. For both warburganal and polygodial, the biofilm inhibitory concentration that inhibits 50% of C. albicans developing biofilms (BIC50) was 4.5 ± 1 and 10.8 ± 5 μg/mL respectively. Against S. aureus developing biofilms, this value was 37.9 ± 8 μg/mL and 25 μg/mL with warburganal and ALA respectively. Eradication of preformed 24 h biofilms was also observed. Interestingly, synergy between the sesquiterpenoids and azoles against developing C. albicans biofilms resulted in an approximately ten-fold decrease of the effective concentration required to completely inhibit growth of the biofilms by individual compounds. The hydroxyl group in position C-9 in warburganal was identified as essential for activity against staphylococcal biofilms. We also identified additional promising bioactive sesquiterpenoids; drimenol and drimendiol from the structure-activity relationship (SAR) studies.

CONCLUSIONS: ALA and four sesquiterpenoids: polygodial, warburganal, drimenol and drimendiol, have shown biofilm-inhibitory activity that has not been reported before and is worth following up. These compounds are potential drug candidates to manage biofilm-based infections, possibly in combination with azoles.}, } @article {pmid31675521, year = {2020}, author = {Zhang, X and Song, Z and Hao Ngo, H and Guo, W and Zhang, Z and Liu, Y and Zhang, D and Long, Z}, title = {Impacts of typical pharmaceuticals and personal care products on the performance and microbial community of a sponge-based moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {295}, number = {}, pages = {122298}, doi = {10.1016/j.biortech.2019.122298}, pmid = {31675521}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; *Microbiota ; Nitrogen ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ± 8.8%, 74.9 ± 8.8% and 28.3 ± 7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.}, } @article {pmid31675193, year = {2019}, author = {Tomiyama, K and Shiiya, T and Watanabe, K and Hamada, N and Mukai, Y}, title = {Effect of toothpaste containing multiple ions-releasing filler on polymicrobial biofilm regrowth and dentin demineralization.}, journal = {American journal of dentistry}, volume = {32}, number = {5}, pages = {245-250}, pmid = {31675193}, issn = {0894-8275}, mesh = {Animals ; Biofilms ; Cattle ; Dentin ; Fluorides ; *Tooth Demineralization ; *Toothpastes ; }, abstract = {PURPOSE: To compare the efficacy of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler particles to that of conventional sodium fluoride (NaF) toothpaste for the prevention of dentin demineralization and biofilm regrowth.

METHODS: Bovine root dentin specimens and glass coverslips were used as biofilm growth substrates. To establish biofilms, glass and dentin specimens were incubated for 72 hours in 0.2% sucrose McBain medium inoculated with stimulated saliva from a single donor. Specimens then received a single 5-minute treatment with S-PRG toothpaste, fluoride toothpaste, or sterilized deionized water and were incubated in McBain medium for 120 hours to allow biofilm regrowth. Output parameters during regrowth (72-192 hours) were pH of spent medium, colony-forming unit (CFU) counts of biofilms, and dentin mineral profiles, integrated mineral loss (IML: vol% × µm), and lesion depth (Ld). Treatment group differences were tested by one-way ANOVA followed by Tukey's multiple range test (P< 0.05).

RESULTS: At 144 hours, medium pH was significantly higher in the S-PRG-treated dentin group than in the NaF-treated dentin group. In addition, at 192 hours, the CFU count, IML, and Ld were lower in the S-PRG-treated dentin group than in the NaF-treated dentin group. There were significant differences of pH among dentin groups at 72 hours. Treatment with S-PRG toothpaste markedly inhibited dentin demineralization compared to that with NaF toothpaste.

CLINICAL SIGNIFICANCE: Toothpaste containing multiple ions-releasing filler suppressed bacterial viability and inhibited dentin demineralization.}, } @article {pmid31673743, year = {2019}, author = {Ding, XS and Zhao, B and An, Q and Tian, M and Guo, JS}, title = {Role of extracellular polymeric substances in biofilm formation by Pseudomonas stutzeri strain XL-2.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {21-22}, pages = {9169-9180}, doi = {10.1007/s00253-019-10188-4}, pmid = {31673743}, issn = {1432-0614}, support = {51208534//National Natural Science Foundation of China/ ; cstc2018jscx-msybX0308//Technical Innovation and Application Demonstration Project of CQ CSTC/ ; }, mesh = {Acyl-Butyrolactones/metabolism ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/*microbiology ; Microscopy, Confocal ; Pseudomonas stutzeri/*growth & development/*metabolism ; Spectroscopy, Fourier Transform Infrared ; alpha-Amylases/metabolism ; beta-Amylase/metabolism ; }, abstract = {Pseudomonas stutzeri strain XL-2 exhibited significant performance on biofilm formation. Extracellular polymeric substances (EPS) secreted by strain XL-2 were characterized by colorimetry and Fourier transform infrared (FT-IR) spectroscopy. The biofilm growth showed a strong positive correlation (rP=0.96, P<0.01) to extracellular protein content, but no correlation to exopolysaccharide content. Hydrolyzing the biofilm with proteinase K caused a significant decrease in biofilm growth (t=3.7, P<0.05), whereas the changes in biofilm growth were not significant when the biofilm was hydrolyzed by α-amylase and β-amylase, implying that proteins rather than polysaccharides played the dominant role in biofilm formation. More specifically, confocal laser scanning microscopy (CLSM) revealed that the extracellular proteins were tightly bound to the cells, resulting in the cells with EPS presenting more biofilm promotion protein secondary structures, such as three-turn helices, β-sheet, and α-helices, than cells without EPS. Both bio-assays and quantitative analysis demonstrated that strain XL-2 produced signal molecules of N-acylhomoserine lactones (AHLs) during biofilm formation process. The concentrations of C6-HLS and C6-oxo-HLS were both significantly positively correlated with protein contents (P<0.05). Dosing exogenous C6-HLS and C6-oxo-HLS also resulted in the increase in protein content. Therefore, it was speculated that C6-HLS and C6-oxo-HLS released by strain XL-2 could up-regulate the secretion of proteins in EPS, and thus promote the formation of biofilm.}, } @article {pmid31673531, year = {2019}, author = {Asadian, M and Azimi, L and Alinejad, F and Ostadi, Y and Lari, AR}, title = {Molecular Characterization of Acinetobacter baumannii Isolated from Ventilator-Associated Pneumonia and Burn Wound Colonization by Random Amplified Polymorphic DNA Polymerase Chain Reaction and the Relationship between Antibiotic Susceptibility and Biofilm Production.}, journal = {Advanced biomedical research}, volume = {8}, number = {}, pages = {58}, pmid = {31673531}, issn = {2277-9175}, abstract = {BACKGROUND: Multidrug-resistant Acinetobacter baumannii can cause complications in antibiotic therapy and increase the rate of morbidity and mortality in hospitalized patients. Patients with ventilator and burns are two specific groups at high risk for A. baumannii infections. This study aimed to determine antibiotic susceptibility patterns associated with biofilm production in A. baumannii and to assess its molecular epidemiology by random amplified polymorphic DNA polymerase chain reaction (RAPD PCR) in A. baumannii isolated from ventilator-associated pneumonia and burn wound colonization.

MATERIALS AND METHODS: In this study, 79 isolates of A. baumannii (32 ventilator-associated pneumonia [VAP] 47 burns) were collected in two teaching hospitals in Tehran, Iran, in 2018. Conventional biochemical and microbiological methods were used to identify bacteria. Antibiotic susceptibility was detected by disc diffusion methods according to the Clinical and Laboratory Standards Institute 2018. Tube test was examined for the detection of the biofilm formation rate in collected strains. The most prevalent carbapenemase genes were detected by PCR and molecular typing by RAPD PCR.

RESULTS: All of bacteria were extensively drug-resistant (XDR) except for two isolates. The results of tube test indicated that only 36% of XDR strains were in weak rate of biofilm formation group. Two major clonal genetic groups were found in VAP and burn strains. Oxa-23 was the most prevalent carbapenemase in collected A. baumannii.

CONCLUSION: The presence of XDR strains of A. baumannii is considerable significant problem in hospitals. Further, similar genetic clonal identified in them indicated the nosocomial infection origin. Hence, these results are very important for control of nosocomial infection committee in health-care systems.}, } @article {pmid31673005, year = {2019}, author = {Brown, JL and Johnston, W and Delaney, C and Rajendran, R and Butcher, J and Khan, S and Bradshaw, D and Ramage, G and Culshaw, S}, title = {Biofilm-stimulated epithelium modulates the inflammatory responses in co-cultured immune cells.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {15779}, pmid = {31673005}, issn = {2045-2322}, support = {BB/P504567/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacteria/*immunology ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Coculture Techniques ; *Gingiva/immunology/microbiology/pathology ; Humans ; Inflammation/immunology/microbiology/pathology ; Inflammation Mediators/*immunology ; *Monocytes/immunology/microbiology/pathology ; *Mouth Mucosa/immunology/microbiology/pathology ; }, abstract = {The gingival epithelium is a physical and immunological barrier to the microbiota of the oral cavity, which interact through soluble mediators with the immune cells that patrol the tissue at the gingival epithelium. We sought to develop a three-dimensional gingivae-biofilm interface model using a commercially available gingival epithelium to study the tissue inflammatory response to oral biofilms associated with "health", "gingivitis" and "periodontitis". These biofilms were developed by sequential addition of microorganisms to mimic the formation of supra- and sub-gingival plaque in vivo. Secondly, to mimic the interactions between gingival epithelium and immune cells in vivo, we integrated peripheral blood mononuclear cells and CD14[+] monocytes into our three-dimensional model and were able to assess the inflammatory response in the immune cells cultured with and without gingival epithelium. We describe a differential inflammatory response in immune cells cultured with epithelial tissue, and more so following incubation with epithelium stimulated by "gingivitis-associated" biofilm. These results suggest that gingival epithelium-derived soluble mediators may control the inflammatory status of immune cells in vitro, and therefore targeting of the epithelial response may offer novel therapies. This multi-cellular interface model, both of microbial and host origin, offers a robust in vitro platform to investigate host-pathogens at the epithelial surface.}, } @article {pmid31671860, year = {2019}, author = {Zhang, Q and Chen, X and Wu, H and Luo, W and Liu, X and Feng, L and Zhao, T}, title = {Comparison of Clay Ceramsite and Biodegradable Polymers as Carriers in Pack-bed Biofilm Reactor for Nitrate Removal.}, journal = {International journal of environmental research and public health}, volume = {16}, number = {21}, pages = {}, pmid = {31671860}, issn = {1660-4601}, mesh = {*Biofilms ; *Bioreactors ; Clay/*chemistry ; Complex Mixtures/*chemistry ; *Denitrification ; Japan ; Nitrates/*chemistry ; Polymers/*chemistry ; Wastewater/*chemistry ; }, abstract = {In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.}, } @article {pmid31671533, year = {2019}, author = {Alshanta, OA and Shaban, S and Nile, CJ and McLean, W and Ramage, G}, title = {Candida albicans Biofilm Heterogeneity and Tolerance of Clinical Isolates: Implications for Secondary Endodontic Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31671533}, issn = {2079-6382}, abstract = {AIM: Endodontic infections are caused by the invasion of various microorganisms into the root canal system. Candida albicans is a biofilm forming yeast and the most prevalent eukaryotic microorganism in endodontic infections. In this study we investigated the ability of C. albicans to tolerate treatment with standard endodontic irrigants NaOCl (sodium hypochlorite), ethylenediaminetetraacetic acid (EDTA) and a combination thereof. We hypothesized that biofilm formed from a panel of clinical isolates differentially tolerate disinfectant regimens, and this may have implications for secondary endodontic infections.

METHODOLOGY: Mature C. albicans biofilms were formed from 30 laboratory and oral clinical isolates and treated with either 3% NaOCl, 17% EDTA or a sequential treatment of 3% NaOCl followed by 17% EDTA for 5 min. Biofilms were then washed, media replenished and cells reincubated for an additional 24, 48 and 72 h at 37 °C. Regrowth was quantified using metabolic reduction, electrical impedance, biofilm biomass and microscopy at 0, 24, 48 and 72 h.

RESULTS: Microscopic analysis and viability readings revealed a significant initial killing effect by NaOCl, followed by a time dependent significant regrowth of C. albicans, but with inter-strain variability. In contrast to NaOCl, there was a continuous reduction in viability after EDTA treatment. Moreover, EDTA significantly inhibited regrowth after NaOCl treatment, though viable cells were still observed.

CONCLUSIONS: Our results indicate that different C. albicans biofilm phenotypes grown in a non-complex surface topography have the potential to differentially tolerate standard endodontic irrigation protocols. This is the first study to report a strain dependent impact on efficacy of endodontic irrigants. Its suggested that within the complex topography of the root canal, a more difficult antimicrobial challenge, that existing endodontic irrigant regimens permit cells to regrow and drive secondary infections.}, } @article {pmid31669377, year = {2020}, author = {Cockeran, R and Dix-Peek, T and Dickens, C and Steel, HC and Anderson, R and Feldman, C}, title = {Biofilm formation and induction of stress response genes is a common response of several serotypes of the pneumococcus to cigarette smoke condensate.}, journal = {The Journal of infection}, volume = {80}, number = {2}, pages = {204-209}, doi = {10.1016/j.jinf.2019.10.014}, pmid = {31669377}, issn = {1532-2742}, mesh = {*Biofilms ; Humans ; Serogroup ; Smoke/*adverse effects ; Smoking ; *Streptococcus pneumoniae/genetics/physiology ; }, abstract = {OBJECTIVES: Exposure to cigarette smoke impacts on the virulence of Streptococcus pneumoniae (pneumococcus) by mechanisms including induction of biofilm formation. Most studies, however, have focused on individual strains of the pneumococcus. Accordingly, the current study has investigated the commonality of the pneumococcal stress response to cigarette smoke condensate (CSC), using five different strains of the pathogen.

METHODS: Following exposure to CSC at final concentrations of 80 and 160 µg mL[-1] during a 16 h incubation period, biofilm formation was measured using a crystal violet-based spectrophotometric procedure. Expression of stress genes seemingly linked to biofilm formation viz. hk11 and rr11 [histidine kinase and response regulator of the two-component regulatory system 11 (TCS11) respectively], cat eff (cation efflux system protein), abc (ATP-binding component of an ATP-binding cassette transporter) and 2005-hyp (hypothetical gene) was measured by sequential extraction of RNA, cDNA synthesis and real-time qPCR.

RESULTS: Exposure of all five strains of the pneumococcus to CSC, resulted in significant biofilm formation, as well as induction of all five test stress genes.

CONCLUSIONS: Augmentation of induction of selective stress genes and biofilm formation are common, possibly linked, responses of various serotypes of the pneumococcus to CSC, favouring both persistence of the pathogen and decreased efficacy of antibiotics.}, } @article {pmid31667388, year = {2019}, author = {Torres, G and Vargas, K and Sánchez-Jiménez, M and Reyes-Velez, J and Olivera-Angel, M}, title = {Genotypic and phenotypic characterization of biofilm production by Staphylococcus aureus strains isolated from bovine intramammary infections in Colombian dairy farms.}, journal = {Heliyon}, volume = {5}, number = {10}, pages = {e02535}, pmid = {31667388}, issn = {2405-8440}, abstract = {The ability of Staphylococcus aureus to form biofilms is an important virulence factor because this has been associated with persistent bovine intramammary infections. Different mechanisms of biofilm formation have been described in S. aureus; however, the process has been found to be mainly driven by the ica and bap genes. The presence of the ica and bap genes, as well as the biofilm formation in vitro were evaluated in 229 S. aureus strains isolated from bovine milk collected from different regions of Department of Antioquia, Colombia. Three different genotypes grouped into three separate clusters were identified from in vitro assays. Genotype 1 (ica positive and bap negative) was the most prevalent (78.17%), followed by genotype 2 (ica and bap positive) (12.66%) and genotype 0 (ica and bap negative) (9.17%). Biofilm formation was observed in 81.26% of the strains from which 100% of genotype 2 isolates showed biofilm formation. The biofilms formed by genotype 2 isolates were also found to have the highest optical density (>2.4). These results showed that most of the S. aureus strains were capable of biofilm formation, suggesting the virulence potential particularly in bap-positive strains.}, } @article {pmid31666981, year = {2019}, author = {Yung, YP and McGill, SL and Chen, H and Park, H and Carlson, RP and Hanley, L}, title = {Reverse diauxie phenotype in Pseudomonas aeruginosa biofilm revealed by exometabolomics and label-free proteomics.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {31}, pmid = {31666981}, issn = {2055-5008}, mesh = {Biofilms/*growth & development ; Carboxylic Acids/*metabolism ; Glucose/*metabolism ; *Metabolism ; Metabolomics ; Proteomics ; Pseudomonas aeruginosa/*growth & development/*metabolism ; }, abstract = {Microorganisms enhance fitness by prioritizing catabolism of available carbon sources using a process known as carbon catabolite repression (CCR). Planktonically grown Pseudomonas aeruginosa is known to prioritize the consumption of organic acids including lactic acid over catabolism of glucose using a CCR strategy termed "reverse diauxie." P. aeruginosa is an opportunistic pathogen with well-documented biofilm phenotypes that are distinct from its planktonic phenotypes. Reverse diauxie has been described in planktonic cultures, but it has not been documented explicitly in P. aeruginosa biofilms. Here a combination of exometabolomics and label-free proteomics was used to analyze planktonic and biofilm phenotypes for reverse diauxie. P. aeruginosa biofilm cultures preferentially consumed lactic acid over glucose, and in addition, the cultures catabolized the substrates completely and did not exhibit the acetate secreting "overflow" metabolism that is typical of many model microorganisms. The biofilm phenotype was enabled by changes in protein abundances, including lactate dehydrogenase, fumarate hydratase, GTP cyclohydrolase, L-ornithine N(5)-monooxygenase, and superoxide dismutase. These results are noteworthy because reverse diauxie-mediated catabolism of organic acids necessitates a terminal electron acceptor like O2, which is typically in low supply in biofilms due to diffusion limitation. Label-free proteomics identified dozens of proteins associated with biofilm formation including 16 that have not been previously reported, highlighting both the advantages of the methodology utilized here and the complexity of the proteomic adaptation for P. aeruginosa biofilms. Documenting the reverse diauxic phenotype in P. aeruginosa biofilms is foundational for understanding cellular nutrient and energy fluxes, which ultimately control growth and virulence.}, } @article {pmid31665633, year = {2019}, author = {Xu, Z and Mandic-Mulec, I and Zhang, H and Liu, Y and Sun, X and Feng, H and Xun, W and Zhang, N and Shen, Q and Zhang, R}, title = {Antibiotic Bacillomycin D Affects Iron Acquisition and Biofilm Formation in Bacillus velezensis through a Btr-Mediated FeuABC-Dependent Pathway.}, journal = {Cell reports}, volume = {29}, number = {5}, pages = {1192-1202.e5}, doi = {10.1016/j.celrep.2019.09.061}, pmid = {31665633}, issn = {2211-1247}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Bacillus/drug effects/*physiology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Biological Transport/drug effects ; Iron/*metabolism ; Models, Biological ; Mutation/genetics ; Operon/genetics ; Oxidation-Reduction ; Protein Binding/drug effects ; Pseudomonas fluorescens/drug effects ; Species Specificity ; Transcription Factors/metabolism ; Up-Regulation/drug effects ; }, abstract = {Bacillus spp. produce a wide range of secondary metabolites, including antibiotics, which have been well studied for their antibacterial properties but less so as signaling molecules. Previous results indicated that the lipopeptide bacillomycin D is a signal that promotes biofilm development of Bacillus velezensis SQR9. However, the mechanism behind this signaling is still unknown. Here, we show that bacillomycin D promotes biofilm development by promoting the acquisition of iron. Bacillomycin D promotes the transcription of the iron ABC transporter FeuABC by binding to its transcription factor, Btr. These actions increase intracellular iron concentration and activate the KinB-Spo0A-SinI-SinR-dependent synthesis of biofilm matrix components. We demonstrate that this strategy is beneficial for biofilm development and competition with the Pseudomonas fluorescens PF-5. Our results unravel an antibiotic-dependent signaling mechanism that links iron acquisition to biofilm development and ecological competition.}, } @article {pmid31663721, year = {2019}, author = {Zhong, N and Wu, Y and Wang, Z and Chang, H and Zhong, D and Xu, Y and Hu, X and Huang, L}, title = {Monitoring Microalgal Biofilm Growth and Phenol Degradation with Fiber-Optic Sensors.}, journal = {Analytical chemistry}, volume = {91}, number = {23}, pages = {15155-15162}, doi = {10.1021/acs.analchem.9b03923}, pmid = {31663721}, issn = {1520-6882}, mesh = {Biofilms/*growth & development ; *Fiber Optic Technology/instrumentation ; Microalgae/*metabolism ; Phenol/chemistry/*metabolism ; }, abstract = {Simple D-type plastic optical fiber (POF) probes (i.e., sensor, reference, and photochemical probes) were created to accurately monitor the progression and phenol degradation of a Chlorella vulgaris biofilm. The sensor and reference probes were used to monitor the biofilm growth (thickness). The sensor probe, which consisted of a D-shaped POF and Canada balsam doped with GeO2 (CBG) coating, was developed to monitor the biofilm growth and change in the liquid-phase composition and its concentration inside the biofilm. The reference probe, which comprised a D-shaped POF, CBG coating, and glass fiber membrane (to separate the liquids from Chlorella vulgaris), was used to measure the response to changes in the liquid phase. A model was developed to demonstrate the accurate measurement of the biofilm thickness. The photochemical POF probe was coupled with a high-permselectivity phenol polymer membrane to monitor the phenol concentration and analyze the degradation time of 50 mg/L phenol with microalgal biofilms. A fixed relationship was obtained between the biofilm sensor output information and biofilm thickness for a biofilm thickness range of 0-290 μm with a periodic supply of 50 mg/L phenol solution. The highest phenol degradation rate occurred at a biofilm thickness of 191-222 μm. The proposed system can be used to investigate microalgal biomass and can provide a promising avenue for research on renewable resources and pollutant degradation.}, } @article {pmid31663364, year = {2019}, author = {Tsiaprazi-Stamou, A and Monfort, IY and Romani, AM and Bakalis, S and Gkatzionis, K}, title = {The synergistic effect of enzymatic detergents on biofilm cleaning from different surfaces.}, journal = {Biofouling}, volume = {35}, number = {8}, pages = {883-899}, doi = {10.1080/08927014.2019.1666108}, pmid = {31663364}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Biofouling/prevention & control ; Detergents/*chemistry ; Disinfection/*methods ; Food-Processing Industry/*standards ; Hydrolases/*chemistry ; Models, Theoretical ; Plastics ; Sanitation/*methods ; Stainless Steel ; Surface Properties ; }, abstract = {Biofilm growth is a significant source of contamination in the food industry. Enzymes are considered green countermeasures against biofilm formation in the food industry owing to their biodegradability and low toxicity. In this study, the synergistic effect of enzymes was studied against biofilm cleaning from hard surfaces. A mixed-microbial sample was sourced from a meat packaging line and biofilms were grown under high shear conditions on stainless steel and polyethylene surfaces. A model cleaning-in-place (CIP) parallel-plate flow chamber was used for firstly, the enzymatic cleaning and secondly, a disinfection step. The cleaning effectiveness was evaluated in response to different formulations containing non-foaming commercial surfactants among with amylase, protease and lipase at neutral pH. The formulation combining all three enzymes was the most effective, showing a synergy essential for the deformation of biofilm structure and consequently better disinfection of both material surfaces.}, } @article {pmid31659674, year = {2020}, author = {Abbas, AF and Al-Saadi, AGM and Alkhudhairy, MK}, title = {Biofilm Formation and Virulence Determinants of Klebsiella oxytoca Clinical Isolates from Patients with Colorectal Cancer.}, journal = {Journal of gastrointestinal cancer}, volume = {51}, number = {3}, pages = {855-860}, doi = {10.1007/s12029-019-00317-7}, pmid = {31659674}, issn = {1941-6636}, mesh = {Adult ; Aged ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/drug effects ; Case-Control Studies ; Colitis/chemically induced/*microbiology ; Colorectal Neoplasms/*microbiology ; Drug Resistance, Multiple, Bacterial/genetics ; Female ; Gastrointestinal Microbiome/*drug effects ; Genes, Bacterial/genetics ; Healthy Volunteers ; Hep G2 Cells ; Humans ; Klebsiella oxytoca/drug effects/genetics/isolation & purification/*pathogenicity ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Virulence/genetics ; Virulence Factors/genetics/isolation & purification ; }, abstract = {OBJECTIVE: Biofilm formation has made the therapy of bacterial infections more difficult. The objective our study was assessment of pan-drug-resistant (PDR) Klebsiella oxytoca pathogenicity and virulence factors causing AAHC in patients with colorectal cancer (CRC).

MATERIALS AND METHODS: Among a total of 300 healthy and 300 patients with antibiotic-associated hemorrhagic colitis (AAHC) and CRC, 200 K. oxytoca were identified during May 2015-January 2019. The virulence properties and biofilm formation among the isolates were investigated by phenotypic, PCR, and real-time PCR (RT-qPCR) techniques.

RESULTS: The blaCTX-M1 (20%), blaSHV (11%), blaTEM1 (33%), and AmpC encoding CIT (2%) ESBL genes, carbapenemase-encoding genes blaIM (4%) and blaOXA-48 (2%), and colistin-resistant mcr-1 gene (2.5%) were detected. The virulence-encoding genes including fimA (80%), pilQ (100%), matB (100%), mrkA (80%), and npsB (100%) were amplified. Therefore, PDR K. oxytoca containing adhesins and toxin-encoding genes with ability of biofilm formation causing AAHC and CRC were isolated. There was a significant difference between healthy and patients with CRC regarding the presence of K. oxytoca (p = 00.221).

CONCLUSION: Bacterial enteric pathogens possibly play a role in CRC. Biofilm formation by K. oxytoca strains prevents the efficient infection elimination; therefore, rapid identification and control measure are chief requirements. Additionally, more investigations are necessary with this regard.}, } @article {pmid31659297, year = {2019}, author = {Díaz-Pascual, F and Hartmann, R and Lempp, M and Vidakovic, L and Song, B and Jeckel, H and Thormann, KM and Yildiz, FH and Dunkel, J and Link, H and Nadell, CD and Drescher, K}, title = {Breakdown of Vibrio cholerae biofilm architecture induced by antibiotics disrupts community barrier function.}, journal = {Nature microbiology}, volume = {4}, number = {12}, pages = {2136-2145}, pmid = {31659297}, issn = {2058-5276}, support = {716734/ERC_/European Research Council/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Metabolomics ; Single-Cell Analysis ; Tetracycline/pharmacology ; Vibrio cholerae/*drug effects/*metabolism ; }, abstract = {Bacterial cells in nature are frequently exposed to changes in their chemical environment[1,2]. The response mechanisms of isolated cells to such stimuli have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure[3-7], which may hold the key to understanding the structure and functions of the most common type of bacterial communities: biofilms. Here, by monitoring all individual cells in Vibrio cholerae biofilms during exposure to antibiotics that are commonly administered for cholera infections, we found that translational inhibitors cause strong effects on cell size and shape, as well as biofilm architectural properties. We identified that single-cell-level responses result from the metabolic consequences of inhibition of protein synthesis and that the community-level responses result from an interplay of matrix composition, matrix dissociation and mechanical interactions between cells. We further observed that the antibiotic-induced changes in biofilm architecture have substantial effects on biofilm population dynamics and community assembly by enabling invasion of biofilms by bacteriophages and intruder cells of different species. These mechanistic causes and ecological consequences of biofilm exposure to antibiotics are an important step towards understanding collective bacterial responses to environmental changes, with implications for the effects of antimicrobial therapy on the ecological succession of biofilm communities.}, } @article {pmid31658838, year = {2019}, author = {Flores-Treviño, S and Bocanegra-Ibarias, P and Camacho-Ortiz, A and Morfín-Otero, R and Salazar-Sesatty, HA and Garza-González, E}, title = {Stenotrophomonas maltophilia biofilm: its role in infectious diseases.}, journal = {Expert review of anti-infective therapy}, volume = {17}, number = {11}, pages = {877-893}, doi = {10.1080/14787210.2019.1685875}, pmid = {31658838}, issn = {1744-8336}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Gram-Negative Bacterial Infections/drug therapy/*epidemiology/microbiology ; Humans ; Immunocompromised Host ; Microbial Sensitivity Tests ; Proteomics ; Stenotrophomonas maltophilia/drug effects/*isolation & purification/physiology ; }, abstract = {Introduction: Infections caused by the opportunistic Stenotrophomonas maltophilia pathogen in immunocompromised patients are complicated to treat due to antibiotic resistance and the ability of the bacteria to produce biofilm.Areas covered: A MEDLINE/PubMed search was performed of available literature to describe the role of biofilm produced by S. maltophilia in the diseases it causes, including biofilm-influencing factors, the biofilm forming process and composition. The antimicrobial resistance due to S. maltophilia biofilm production and current antibiofilm strategies is also included.Expert opinion: Through the production of biofilm, S. maltophilia strains can easily adhere to the surfaces in hospital settings and aid in its transmission. The biofilm can also cause antibiotic tolerance rendering some of the therapeutic options ineffective, causing setbacks in the selection of an appropriate treatment. Conventional susceptibility tests do not yet offer therapeutic guidelines to treat biofilm-associated infections. Current S. maltophilia biofilm control strategies include natural and synthetic compounds, chelating agents, and commonly prescribed antibiotics. As biofilm age and matrix composition affect the level of antibiotic tolerance, their characterization should be included in biofilm susceptibility testing, in addition to molecular and proteomic analyzes. As for now, several commonly recommended antibiotics can be used to treat biofilm-related S. maltophilia infections.}, } @article {pmid31658638, year = {2019}, author = {Thakur, D and Govindaraju, S and Yun, K and Noh, JS}, title = {The Synergistic Effect of Zinc Ferrite Nanoparticles Uniformly Deposited on Silver Nanowires for the Biofilm Inhibition of Candida albicans.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {31658638}, issn = {2079-4991}, support = {2019R1A2C1008746//National Research Foundation of Korea/ ; 2016R1D1A1B03932515//National Research Foundation of Korea/ ; }, abstract = {Near-monodisperse zinc ferrite nanoparticles (ZnFe2O4 NPs) are synthesized by a co-precipitation method and deposited on the surface of silver nanowires (AgNWs), employing a stepwise solution method. The resulting hybrid nanostructures (ZnFe2O4@AgNWs) show a thin and uniform layer of ZnFe2O4 NPs at an optimum weight ratio of 1:6 between the two component nanostructures. The hybrid nanostructures retain the high crystal quality and phase purity of their constituents. It is demonstrated that the ZnFe2O4@AgNWs hybrid nanostructures are effective at inhibiting the biofilm formation of Candida albicans cells. The biofilm inhibition activity of the hybrid nanostructures is estimated to be more than 50% at a low concentration of 100 µg/mL from both crystal violet assay and XTT assay, which are more than 8-fold higher than those of pure AgNWs and ZnFe2O4 NPs. This greatly enhanced biofilm inhibition activity is attributed to the ZnFe2O4 NPs-carrying membrane penetration by AgNWs and the subsequent interaction between Candida cells and ZnFe2O4 NPs. These results indicate that the ZnFe2O4@AgNWs hybrid nanostructures have great potential as a new type of novel antibiofilm agent.}, } @article {pmid31656524, year = {2019}, author = {Betesho Babrud, R and Kasra Kermanshahi, R and Motamedi Sede, F and Moosavinejad, SZ}, title = {The effect of Lactobacillus reuteri cell free supernatant on growth and biofilm formation of Paenibacillus larvae.}, journal = {Iranian journal of veterinary research}, volume = {20}, number = {3}, pages = {192-198}, pmid = {31656524}, issn = {1728-1997}, abstract = {BACKGROUND: Paenibacillus larvae is the etiological agent of American foulbrood (AFB) disease, the most lethal disease in honeybee (Apis mellifera) larvae.

AIMS: The aim of the present work was to study the antimicrobial effect of cell free supernatant (CFS) of probiotics on an Iranian isolate's biofilm formation.

METHODS: A local strain was identified by 16S rRNA sequencing. The antibacterial effect of some probiotics was evaluated through drop plate method, minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and time-kill assay. The biofilm formation ability of P. larvae and the inhibition of biofilm formation by CFS were studied by microplate and scanning electron microscopy (SEM). The nature of the secondary metabolites in CFS was examined by microscale optical density assay (MODA).

RESULTS: Alignment of the results of P. larvae KB10 (GenBank accession number MH000685.1) 16S rRNA with the database revealed more than 97% identity with P. larvae . The most antibacterial effect was observed in the CFS of Lactobacillus reuteri ATCC23272 with 12.75 ± 3.2 mm for zone of inhibition (ZOI) at 1000 µL/ml for MIC and MBC. Time-kill assay revealed that CFS eliminated 1.5 × 10[8] CFU/ml P. larvae KB10 at 2 h of exposure. Microtitre plate and SEM results revealed that CFS (at sub-MIC concentration) was able to inhibit biofilm formation by P. larvae. The results of MODA assay showed that antimicrobial activity were related to the production of organic acids.

CONCLUSION: Cell free supernatant from L. reuteri ATCC 23272 had inhibitory effects on P. larvae KB10 growth and biofilm production due to its acidic nature. The obtained results can be used for antibiotic substitution in AFB control and treatment.}, } @article {pmid31656155, year = {2020}, author = {Ielapi, N and Nicoletti, E and Lorè, C and Guasticchi, G and Avenoso, T and Barbetta, A and de Franciscis, S and Andreucci, M and Sapienza, P and Serra, R}, title = {The Role of Biofilm in Central Venous Catheter Related Bloodstream Infections: Evidence-based Nursing and Review of the Literature.}, journal = {Reviews on recent clinical trials}, volume = {15}, number = {1}, pages = {22-27}, doi = {10.2174/1574887114666191018144739}, pmid = {31656155}, issn = {1876-1038}, mesh = {*Biofilms ; Catheter-Related Infections/*etiology ; Central Venous Catheters/*adverse effects ; Evidence-Based Nursing ; Humans ; Sepsis/*etiology ; }, abstract = {BACKGROUND: Biofilm is a fundamental component in the pathogenesis of infections related to the use of the central venous catheter (CVC,) which can represent an important health issue in everyday practice of nursing and medical staff.

OBJECTIVE: The objective of the following review is to analyze the components of biofilm and their role in catheter-related infection determinism in an evidencebased nursing perspective in such a way as to give health professionals useful suggestions in the prevention and management of these complications.

METHODS: The following databases were consulted for the bibliographic search: Medline, Scopus, Science Direct. Biofilm can be the cause of CVC extraction and can lead to serious haematogenic infectious complications that can increase the morbidity and mortality of affected patients.

RESULTS: Updated pathophysiologic knowledge of biofilm formation and appropriate diagnostic methodology are pivotal in understanding and detecting CVC-related infections. Lock therapy appears to be a useful, preventive, and therapeutic aid in the management of CVCrelated infections. New therapies attempting to stop bacterial adhesion on the materials used could represent new frontiers for the prevention of CVC-related infections.

CONCLUSION: The correct evidence-based nursing methods, based on the use of guidelines, provides the opportunity to minimize the risks of infection through the implementation of a series of preventive measures both during the CVC positioning phase and in the subsequent phase, for example, during device management which is performed by medical and nursing staff.}, } @article {pmid31655088, year = {2019}, author = {Narmani, A and Teponno, RB and Helaly, SE and Arzanlou, M and Stadler, M}, title = {Cytotoxic, anti-biofilm and antimicrobial polyketides from the plant associated fungus Chaetosphaeronema achilleae.}, journal = {Fitoterapia}, volume = {139}, number = {}, pages = {104390}, doi = {10.1016/j.fitote.2019.104390}, pmid = {31655088}, issn = {1873-6971}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Antineoplastic Agents/isolation & purification/*pharmacology ; Ascomycota/*chemistry ; Biofilms/*drug effects ; Humans ; Iran ; MCF-7 Cells ; Microbial Sensitivity Tests ; Molecular Structure ; Staphylococcus aureus/drug effects ; Taxus/*microbiology ; }, abstract = {From extracts of the plant associated fungus Chaetosphaeronema achilleae collected in Iran, a previously unreported isoindolinone named chaetosisoindolinone (1) and a previously undescribed indanone named chaetosindanone (2) were isolated in addition to five known metabolites, 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (3), vulculic acid (4), 2-(2-acetyl-3-hydroxy-5-methoxyphenyl)acetic acid (5), curvulin (6), and curvulol (7). Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. The isolated compounds were tested for their antimicrobial, anti-biofilm, and nematicidal activities. Compound 2 exhibited cytotoxicity against the human breast adenocarcinoma MCF-7 cells with an IC50 value of 1.5 μg/mL. Furthermore, compounds 4 and 7 almost completely inhibited biofilm formation in Staphylococcus aureus at 256 μg/mL. Weak antimicrobial activities were also observed for some of the isolated compounds against Mucor hiemalis, Rhodoturula glutinis, Chromobacterium violaceum, and Staphylococcus aureus.}, } @article {pmid31654510, year = {2019}, author = {Singla, RK and Dubey, AK}, title = {Molecules and Metabolites from Natural Products as Inhibitors of Biofilm in Candida spp. pathogens.}, journal = {Current topics in medicinal chemistry}, volume = {19}, number = {28}, pages = {2567-2578}, pmid = {31654510}, issn = {1873-4294}, mesh = {Antifungal Agents/chemistry/metabolism/*pharmacology ; Biofilms/*drug effects ; Biological Products/chemistry/metabolism/*pharmacology ; Candida/classification/*drug effects/*pathogenicity ; Humans ; Microbial Sensitivity Tests ; Plants, Medicinal ; Species Specificity ; }, abstract = {BACKGROUND: Biofilm is a critical virulence factor associated with the strains of Candida spp. pathogens as it confers significant resistance to the pathogen against antifungal drugs.

METHODS: A systematic review of the literature was undertaken by focusing on natural products, which have been reported to inhibit biofilms produced by Candida spp. The databases explored were from PubMed and Google Scholar. The abstracts and full text of the manuscripts from the literature were analyzed and included if found significant.

RESULTS: Medicinal plants from the order Lamiales, Apiales, Asterales, Myrtales, Sapindales, Acorales, Poales and Laurales were reported to inhibit the biofilms formed by Candida spp. From the microbiological sources, lactobacilli, Streptomyces chrestomyceticus and Streptococcus thermophilus B had shown the strong biofilm inhibition potential. Further, the diverse nature of the compounds from classes like terpenoids, phenylpropanoid, alkaloids, flavonoids, polyphenol, naphthoquinone and saponin was found to be significant in inhibiting the biofilm of Candida spp.

CONCLUSION: Natural products from both plant and microbial origins have proven themselves as a goldmine for isolating the potential biofilm inhibitors with a specific or multi-locus mechanism of action. Structural and functional characterization of the bioactive molecules from active extracts should be the next line of approach along with the thorough exploration of the mechanism of action for the already identified bioactive molecules.}, } @article {pmid31653277, year = {2019}, author = {Gholami, SA and Goli, HR and Haghshenas, MR and Mirzaei, B}, title = {Evaluation of polysaccharide intercellular adhesion (PIA) and glycerol teichoic acid (Gly-TA) arisen antibodies to prevention of biofilm formation in Staphylococcus aureus and Staphylococcus epidermidis strains.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {691}, pmid = {31653277}, issn = {1756-0500}, mesh = {Animals ; Antibodies/*immunology/pharmacology ; Bacterial Adhesion/*immunology ; Biofilms/drug effects/*growth & development ; Colorimetry ; Female ; Mice ; Mice, Inbred BALB C ; Polysaccharides, Bacterial/*immunology ; Spectroscopy, Fourier Transform Infrared ; Staphylococcal Infections/immunology/microbiology/prevention & control ; Staphylococcus aureus/drug effects/*immunology/physiology ; Staphylococcus epidermidis/drug effects/*immunology/physiology ; Teichoic Acids/*immunology/metabolism ; }, abstract = {OBJECTIVE: Staphylococcus aureus and S. epidermidis as opportunistic pathogens, notable for their frequency and severity of infections are recognized as the most usual reasons for medical device-associated infections that strike hospitalized patients and also immunocompromised individuals. In this study, the polysaccharide intercellular adhesion (PIA) and Glycerol teichoic acid) Gly-TA) as two major macromolecules in the biofilm formation process were purified under the native condition and their structure was analyzed by using colorimetric assays and Fourier Transform Infrared spectroscopy (FTIR). Afterward, the immune response of macromolecules and the mixture of them were assessed by measuring total IgG titers. Subsequently, biofilm inhibitory effects of raising antibodies to biofilm former S. aureus and S. epidermidis were evaluated.

RESULTS: Obtained data were shown a significant rise in levels of antibodies in immunized mice with mentioned antibodies in comparison with the control group. According to the obtained findings, mentioned antibodies could eliminate S. aureus and S. epidermidis biofilm formation in vitro assays. This survey confirms the proposal that immunization of mice with a mixture of Gly-TA and PIA vaccine could be secure and protected against S. epidermidis and S. aureus infection.}, } @article {pmid31652836, year = {2019}, author = {Choi, JS and Lee, JW and Shin, UC and Lee, MW and Kim, DJ and Kim, SW}, title = {Inhibitory Activity of Silver Nanoparticles Synthesized Using Lycopersicon Esculentum against Biofilm Formation in Candida Species.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {9}, number = {11}, pages = {}, pmid = {31652836}, issn = {2079-4991}, support = {P0006675//Ministry of Trade, Industry and Energy(MOTIE) and Korea Institute for Advancement of Technology(KIAT)/ ; }, abstract = {This paper investigated the antifungal and antibiofilm activity of silver nanoparticles synthesized with Lycopersicon esculentum extracts against Candida species. Lycopersicon esculentum extracts obtained by homogenization were mixed with silver nitrate to synthesize silver nanoparticles. Analysis of the particle characteristics by UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR) confirmed that the Lycopersicon esculentum extracts effectively served as reductants and capping agents. Minimum inhibitory concentration (MIC) tests were conducted to confirm antifungal activity against Candida species. In all the tested species, the silver nanoparticles inhibited the growth of Candida. Moreover, the SEM images of Candida species treated with silver nanoparticles synthesized using natural extracts of Lycopersicon esculentum showed that silver nanoparticles adhered to the surface of Candida, which induced pore formation in the membranes and prevented their normal growth. Ultimately, these abnormal forms of Candida were thought to be less able to form biofilms than normal Candida. The antifungal and antibiofilm activities of silver nanoparticles against Candida are expected to be utilized in various fields and contribute in particular to developments in nanomedicine.}, } @article {pmid31652575, year = {2019}, author = {Maletskyi, Z and Zigta, DK and Kulesha, O and Ratnaweera, H}, title = {Chemical Enhancement for Retrofitting Moving Bed Biofilm and Integrated Fixed Film Activated Sludge Systems into Membrane Bioreactors.}, journal = {Membranes}, volume = {9}, number = {10}, pages = {}, pmid = {31652575}, issn = {2077-0375}, abstract = {Positive effects of retrofitting MBBR and IFAS systems into MBRs can be exploited by introducing chemical enhancement applying coagulants in the membrane separation step. The current study reports basic principles of chemical enhancement with aluminium sulphate coagulant in biofilm-MBR (Bf-MBR) based on results of total recycle tests performed at different dosages of the chemical enhancer and properties characterization of filtrates, supernatants and sediments. It demonstrates a possibility to achieve lower membrane fouling rates with dosing of aluminium sulphate coagulant into MBBR and IFAS mixed liquors by extending operational cycles by 20 and 80 time respectively as well as increasing operating permeability of membrane separation by 1.3 times for IFAS. It has been found that charge neutralization is the dominating mechanism of aluminium sulphate action as a chemical enhancer in Bf-MBR, however, properties of the membrane surface influencing charge repulsion of foulants should be considered together with the secondary ability of the coagulant to improve consolidation of sediments.}, } @article {pmid31651349, year = {2019}, author = {Lee, S and Hwang, J and Kim, J and Lee, J and Kim, HC and Rhim, H and Han, JI}, title = {Biofilm production of coagulase-negative staphylococci isolated from rescued wild animals in the Republic of Korea.}, journal = {Acta veterinaria Scandinavica}, volume = {61}, number = {1}, pages = {50}, pmid = {31651349}, issn = {1751-0147}, support = {2016R1D1A3B03932480//National Research Foundation of Korea/ ; 2016000210002//ministry of envirionment korea/ ; }, mesh = {Animals ; Animals, Wild ; *Biofilms ; Coagulase/metabolism ; *Drug Resistance, Bacterial ; Republic of Korea/epidemiology ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus/*drug effects/*physiology ; }, abstract = {Biofilm production is a well-known causative factor of catheter- and medical device-related sepsis. Its high prevalence in coagulase-negative staphylococci (CoNS) has recently been reported. Information on biofilm production in CoNS isolated from wild animals is lacking. Herein, we studied the biofilm formation capabilities of CoNS isolated from rescued wild animals in the Republic of Korea. Swab samples were collected from the conjunctiva, nasal cavity, perianal area, and rectum for mammals while the sampling was done from the conjunctiva, oral mucosa, pericloacal area, and cloaca for birds. Isolation of CoNS was based on morphological and biochemical analyses along with molecular typing. Biofilm production was analyzed using 96-well plate based quantitative adherence assays. The studies demonstrated that CoNS of mammalian origin have higher biofilm-producing ability (70.4%) than the isolates from birds (62.5%). In particular, all methicillin-resistant (MR) CoNS isolated from mammals were capable of biofilm formation while only 63.3% of MR CoNS isolated from birds could produce biofilms. The MR CoNS isolated from mammals also had a significantly higher ability to form biofilms (100%) than methicillin susceptible CoNS (60.0%) than those isolates from birds. The findings show that wild animals may act as reservoirs as well as possible transmitters of biofilm-mediated antibiotic resistant genes.}, } @article {pmid31649642, year = {2019}, author = {Tan, F and She, P and Zhou, L and Liu, Y and Chen, L and Luo, Z and Wu, Y}, title = {Bactericidal and Anti-biofilm Activity of the Retinoid Compound CD437 Against Enterococcus faecalis.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2301}, pmid = {31649642}, issn = {1664-302X}, abstract = {Enterococcus faecalis (E. faecalis), a biofilm-forming pathogen, causes nosocomial infections. In recent years, drug resistance by enterococci has become increasingly severe due to widespread antibiotic abuse. Therefore, novel antibacterial agents are urgently needed. In this study, the synthetic retinoid compound CD437 was found to have potent bactericidal effect on E. faecalis. In addition, CD437 exhibited synergistic effects when administered in combination with gentamicin and additive effects when combined with ceftriaxone sodium. CD437 also inhibited biofilm formation by E. faecalis and exerted bactericidal effect on mature biofilm. Moreover, CD437 exhibited antibacterial and anti-biofilm effects against Staphylococcus. No bactericidal action of CD437 was observed against the gram-negative bacillus, but Pseudomonas aeruginosa biofilm extracellular polymeric substances (EPS) matrix formation was reduced. Overall, these findings indicate that CD437 has the potential to be developed as a novel antibacterial drug.}, } @article {pmid31648793, year = {2019}, author = {Park, JW and An, JS and Lim, WH and Lim, BS and Ahn, SJ}, title = {Microbial changes in biofilms on composite resins with different surface roughness: An in vitro study with a multispecies biofilm model.}, journal = {The Journal of prosthetic dentistry}, volume = {122}, number = {5}, pages = {493.e1-493.e8}, doi = {10.1016/j.prosdent.2019.08.009}, pmid = {31648793}, issn = {1097-6841}, mesh = {Bacterial Adhesion ; Biofilms ; *Composite Resins ; *Streptococcus mutans ; Surface Properties ; }, abstract = {STATEMENT OF PROBLEM: The single-species biofilm method cannot represent the interaction and complex functions of microorganisms associated with oral biofilms.

PURPOSE: The purpose of this in vitro study was to investigate microbial changes in biofilms on composite resins of varying surface roughness by using a multispecies biofilm model with early-colonizing streptococci, middle colonizer, and late-colonizing gram-negative anaerobes.

MATERIAL AND METHODS: Composite resin disks were prepared with different roughness: SR180, SR400, SR1500, and SRGlass roughened with 180-, 400-, and 1500-grit silicon carbide paper and glass (control surface without surface roughening). Surface roughness was analyzed by confocal laser scanning and scanning electron microscopy. After multispecies biofilms had been grown on the composite resin surfaces, the adhesion of Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and of total bacteria was determined after 1 (T1) and 4 (T2) days. Differences in surface roughness among the 4 groups were tested with 1-way ANOVA. Multifactorial analysis of variance was used to determine the time-related differences in the bacterial composition with respect to surface roughness (α=.05).

RESULTS: The order of SR, from highest to lowest, was SR180 (1.45 ±0.11 μm), SR400 (0.62 ±0.05 μm), SR1500 (0.35 ±0.02 μm), and SRGlass (0.15 ±0.01 μm) (SR180>SR400>SR1500>SRGlass, P<.001). Increased surface roughness was not proportional to bacterial adhesion. Significant differences in the adhesion of total bacteria was only found between SRGlass and SR180 (SR180>SRGlass, P=.029). The adhesion of S. mutans and S. sobrinus to SR180 and SR400 was higher than that to SRGlass (SR180=SR400>SRGlass; S. mutans, P=.003; S. sobrinus, P=.002). However, the adhesion of A. actinomycetemcomitans and P. gingivalis to composite resin was not significantly influenced by surface roughness. Adhesion of total bacteria, S. mutans, and S. sobrinus increased from T1 to T2 (T1T2; A. actinomycetemcomitans, P<.001; P. gingivalis, P=.013).

CONCLUSIONS: Decreased adhesion of cariogenic streptococci and total bacteria was observed at surface roughness values of around 0.15 μm. Periodic finishing of surface roughness should be considered to minimize the adhesion of cariogenic streptococci to composite resin surfaces.}, } @article {pmid31647407, year = {2019}, author = {Sugathan, S and Mandal, J}, title = {An in vitro experimental study of the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.}, journal = {Journal of medical microbiology}, volume = {68}, number = {12}, pages = {1699-1706}, doi = {10.1099/jmm.0.001061}, pmid = {31647407}, issn = {1473-5644}, mesh = {Amikacin/administration & dosage/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/administration & dosage/pharmacology ; Drug Synergism ; Escherichia coli/drug effects/*physiology ; Fosfomycin/administration & dosage/pharmacology ; Humans ; Meropenem/administration & dosage/pharmacology ; Microbial Sensitivity Tests ; Urinary Tract Infections/*microbiology ; }, abstract = {Background. This study was conducted to understand the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.Methods. Fifty urinary tract multidrug-resistant E. coli isolates that were known biofilm producers were studied. The MIC was determined using the agar dilution method for amikacin, ciprofloxacin, meropenem and fosfomycin. The fractional inhibitory concentration was determined for the combination of antibiotics followed by a time-kill assay. A tissue culture plate method was used to study the effect of the combination of antibiotics on biofilm formation.Results. The MICs of the isolates tested ranged from 0.25 to 32 µg ml[-1] for fosfomycin, 1 to 1024 µg ml[-1] for ciprofloxacin, 4 to 1024 µg ml[-1] for amikacin, and 0.25 to 512 µg ml[-1] for meropenem. The combination of fosfomycin with meropenem showed 68 % synergy, fosfomycin with amikacin 58 % synergy and fosfomycin with ciprofloxacin 6 % synergy. The combination also reduced the MIC of each antibiotic and none showed an antagonistic effect. Biofilm inhibition was best observed with the combination of fosfomycin with meropenem.Conclusion. The combination of fosfomycin with amikacin and fosfomycin with meropenem yielded a high percentage of synergy alongside an increased capacity to reduce biofilm formation when compared to combination with ciprofloxacin against multidrug-resistant E. coli. Fosfomycin in combination with other classes of antimicrobial agents has potential beneficial effects.}, } @article {pmid31646898, year = {2019}, author = {Alvim, DCSS and Ferreira, AFM and Leal, MA and Oliveira, LMA and Botelho, AMN and Botelho, ACN and Figueiredo, AMS and Fracalanzza, SEL and Teixeira, LM and Pinto, TCA}, title = {Biofilm production and distribution of pilus variants among Streptococcus agalactiae isolated from human and animal sources.}, journal = {Biofouling}, volume = {35}, number = {8}, pages = {938-944}, doi = {10.1080/08927014.2019.1678592}, pmid = {31646898}, issn = {1029-2454}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; DNA, Bacterial ; Fimbriae, Bacterial/*genetics ; Genetic Variation ; Humans ; Streptococcal Infections/*microbiology ; Streptococcus agalactiae/genetics/growth & development/*isolation & purification ; Virulence Factors/genetics ; }, abstract = {Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.}, } @article {pmid31646225, year = {2019}, author = {Saigal, and Irfan, M and Khan, P and Abid, M and Khan, MM}, title = {Design, Synthesis, and Biological Evaluation of Novel Fused Spiro-4H-Pyran Derivatives as Bacterial Biofilm Disruptor.}, journal = {ACS omega}, volume = {4}, number = {16}, pages = {16794-16807}, pmid = {31646225}, issn = {2470-1343}, abstract = {This study aims to synthesize novel fused spiro-4H-pyran derivatives under green conditions to develop agents having antimicrobial activity. The synthesized compounds were initially screened for in vitro antibacterial activity against two Gram-positive and three Gram-negative bacterial strains, and all the compounds exhibited moderate to potent antibacterial activity. However, compound 4l showed significant inhibition toward all the bacterial strains, particularly against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentration values of 125 μg/mL for each. The toxicity studies of selected compounds (4c, 4e, 4l, and 4m) using human red blood cells as well as human embryonic kidney (HEK-293) cells showed nontoxic behavior at desired concentration. Growth kinetic and time-kill curve studies of 4l against S. pneumoniae and E. coli supported its bactericidal nature. Interestingly, compound 4l showed a synergistic effect when used in combination with ciprofloxacin against selected strains. Biofilm formation in the presence of a lead compound, as assessed by XTT assay, showed complete disruption of the bacterial biofilm visualized by scanning electron microscopy. Overall, the findings suggest 4l to be considered as a promising lead for further development as an antibacterial agent.}, } @article {pmid31646145, year = {2019}, author = {Aliramezani, A and Soleimani, M and Fard, RMN and Nojoomi, F}, title = {Virulence determinants and biofilm formation of Acinetobacter baumannii isolated from hospitalized patients.}, journal = {Germs}, volume = {9}, number = {3}, pages = {148-153}, pmid = {31646145}, issn = {2248-2997}, abstract = {INTRODUCTION: Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients.

METHODS: In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed.

RESULTS: Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were α-hemolytic on Brucella blood agar media and all isolates displayed proteolytic activity.

CONCLUSIONS: Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.}, } @article {pmid31646012, year = {2019}, author = {Masters, EA and Trombetta, RP and de Mesy Bentley, KL and Boyce, BF and Gill, AL and Gill, SR and Nishitani, K and Ishikawa, M and Morita, Y and Ito, H and Bello-Irizarry, SN and Ninomiya, M and Brodell, JD and Lee, CC and Hao, SP and Oh, I and Xie, C and Awad, HA and Daiss, JL and Owen, JR and Kates, SL and Schwarz, EM and Muthukrishnan, G}, title = {Evolving concepts in bone infection: redefining "biofilm", "acute vs. chronic osteomyelitis", "the immune proteome" and "local antibiotic therapy".}, journal = {Bone research}, volume = {7}, number = {}, pages = {20}, pmid = {31646012}, issn = {2095-4700}, support = {P50 AR072000/AR/NIAMS NIH HHS/United States ; R01 AR043510/AR/NIAMS NIH HHS/United States ; }, abstract = {Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.}, } @article {pmid31642854, year = {2019}, author = {Chen, L and Yang, D and Feng, J and Zhang, M and Qian, Q and Zhou, Y}, title = {Switchable modulation of bacterial growth and biofilm formation based on supramolecular tripeptide amphiphiles.}, journal = {Journal of materials chemistry. B}, volume = {7}, number = {41}, pages = {6420-6427}, doi = {10.1039/c9tb00973f}, pmid = {31642854}, issn = {2050-7518}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Bacteria/drug effects/growth & development ; Biofilms/drug effects/growth & development ; Hydrophobic and Hydrophilic Interactions ; Nanofibers/chemistry ; Oligopeptides/*chemistry/pharmacology ; Surface-Active Agents/*chemistry ; }, abstract = {Design and fabrication of smart supramolecular peptide systems is an effective strategy to develop antibacterial agents that can be selectively activated/inactivated by external stimuli for combating bacterial resistance. In this work, we selectively synthesized isomeric tripeptides (i.e., Ala-Gly-Gly-OH and Gly-Gly-Ala-OH) with the simplest structures to construct a minimalistic dual-responsive supramolecular antibacterial system. To impart stimuli-responsiveness, the tripeptides were modified using a hydrophobic n-butylazobenzene tail at the N-terminal, which benefited the enhancement of the hydrophobicity of the tripeptides and they served as synergistic antibacterial moieties. Two different self-assembled 1-D morphologies (i.e., nanotwists and nanofibers) were observed under the same conditions when the position of the Ala residue was altered. More importantly, the supramolecular tripeptide amphiphiles exhibited a reversible assembly/disassembly process in response to different stimuli (i.e., light and host-guest chemistry). Based on the stimuli-responsiveness, the antibacterial/antibiofilm activities against either Gram-negative or Gram-positive bacteria could be reversibly modulated.}, } @article {pmid31642039, year = {2020}, author = {Ortega-Peña, S and Martínez-García, S and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {Overview of Staphylococcus epidermidis cell wall-anchored proteins: potential targets to inhibit biofilm formation.}, journal = {Molecular biology reports}, volume = {47}, number = {1}, pages = {771-784}, pmid = {31642039}, issn = {1573-4978}, support = {20181167//SIP-Instituto Politécnico Nacional Mexico/ ; }, mesh = {*Anti-Bacterial Agents ; *Bacterial Proteins ; Biofilms/*drug effects ; *Cell Wall ; Drug Discovery ; Humans ; Immunotherapy ; Staphylococcal Infections/microbiology ; *Staphylococcus epidermidis/chemistry/cytology/drug effects ; }, abstract = {Currently, the treatment of infections by Staphylococcus epidermidis (S. epidermidis) represents a challenge because some strains have multidrug-resistance to antimicrobial products (antibiotic and biocides) and can produce biofilms. These biofilms protect bacterial cells from both antimicrobials and the host immune response. Therefore, it is crucial to encourage research on the development of new treatments. One method is immunotherapy, targeting components of S. epidermidis, such as S. epidermidis surface (Ses) proteins. Ses is expressed constitutively in most strains, and they participate in biofilm formation. This review is an update on Ses, regarding their structure, biological function, their relationship with S. epidermidis biofilm formation, and its possible role as therapeutic targets to develop immunotherapeutic treatments to prevent infections by S. epidermidis.}, } @article {pmid31641666, year = {2019}, author = {Raya, S and Belbase, A and Dhakal, L and Govinda Prajapati, K and Baidya, R and Kishor Bimali, N}, title = {In-Vitro Biofilm Formation and Antimicrobial Resistance of Escherichia coli in Diabetic and Nondiabetic Patients.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {1474578}, pmid = {31641666}, issn = {2314-6141}, mesh = {Adolescent ; Adult ; Aged ; Amikacin/therapeutic use ; Amoxicillin/therapeutic use ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/drug effects/*growth & development ; Cross-Sectional Studies ; *Diabetes Complications ; Diabetes Mellitus/*microbiology ; Disk Diffusion Antimicrobial Tests ; *Drug Resistance, Multiple, Bacterial/drug effects ; Escherichia coli Infections/drug therapy ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Trimethoprim, Sulfamethoxazole Drug Combination/therapeutic use ; Urinary Tract Infections/*complications/*microbiology ; Uropathogenic Escherichia coli/*drug effects/isolation & purification/pathogenicity ; Young Adult ; }, abstract = {BACKGROUND: Diabetic patients are more susceptible to urinary tract infection compared to nondiabetic patients, Escherichia coli being the most common uropathogen causing UTI. Unreasonable and incorrect antibiotic prescription for UTI in these patients may induce the development of antibiotic-resistant urinary pathogens resulting in delayed recovery and longer hospitalization. In addition to these, biofilm forming capacity of the pathogen may worsen the problem. The main aim of this cross-sectional study (conducted from March to September 2015) is to detect the biofilm forming capacity of UTI causing micro-organisms and compare the antibiotic resistance pattern of Escherichia coli, the most common cause of UTI, which will help the physician in choosing the best antibiotic.

METHOD: Total of 1,099 clean-catch mid stream urine (CCMSU) was processed by standard microbiological technique; 182 were from the diabetic group and 917 nondiabetic. Following identification, all isolates were subjected to antibiotic susceptibility testing using modified Kirby-Bauer disc diffusion method. In-vitro biofilm forming capacity of the isolates were detected by Microtitre plate method. The data were analyzed using SPSS software 16.

RESULT: Urinary tract infection was found to be significantly higher in diabetic patients (42.9%) compared to nondiabetic patients (17.4%) with Escherichia coli as the most common uropathogen in both diabetic and nondiabetic groups. Similarly, UTI was more common in elderly population (29.5%). Imipenem, nitrofurantoin and amikacin were found to be the most effective drug for uropathogenic E. coli in both diabetic and nondiabetic patients, whereas amoxicillin, ciprofloxacin, and cotrimoxazole were least effective. Of the total bacterial isolates, 43.3% showed positive results for in-vitro biofilm production by the Microtitre plate method. A significantly higher resistance rate was observed among biofilm producing E. coli for quinolones, cotrimoxazole, and third generation cephalosporin ceftriaxone. Most of the biofilm producers (79.5%) were found to be MDR (p-value 0.015).

CONCLUSION: Elderly populations with diabetes are at a higher risk of UTI. Higher biofilm production and resistance to in-use antimicrobial agents in this study render its inefficacy for empirical treatment and point out the importance of biofilm screening to ensure the effective management of infection.}, } @article {pmid31640553, year = {2019}, author = {Król, JE and Hall, DC and Balashov, S and Pastor, S and Sibert, J and McCaffrey, J and Lang, S and Ehrlich, RL and Earl, J and Mell, JC and Xiao, M and Ehrlich, GD}, title = {Genome rearrangements induce biofilm formation in Escherichia coli C - an old model organism with a new application in biofilm research.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {767}, pmid = {31640553}, issn = {1471-2164}, support = {R01 AI080935/AI/NIAID NIH HHS/United States ; R01 DC002148/DC/NIDCD NIH HHS/United States ; R01 DC004173/DC/NIDCD NIH HHS/United States ; 5R01 DC 02148/DC/NIDCD NIH HHS/United States ; }, mesh = {Bacterial Adhesion/genetics ; Biofilms/*growth & development ; Chromosome Mapping ; Escherichia coli/*genetics/growth & development ; Escherichia coli Proteins/genetics ; Gene Expression Regulation, Bacterial ; Genes, Regulator/genetics ; Genome, Bacterial/*genetics ; Promoter Regions, Genetic ; Salt Stress/genetics ; Sequence Inversion ; Temperature ; Transcription Factors/genetics ; }, abstract = {BACKGROUND: Escherichia coli C forms more robust biofilms than other laboratory strains. Biofilm formation and cell aggregation under a high shear force depend on temperature and salt concentrations. It is the last of five E. coli strains (C, K12, B, W, Crooks) designated as safe for laboratory purposes whose genome has not been sequenced.

RESULTS: Here we present the complete genomic sequence of this strain in which we utilized both long-read PacBio-based sequencing and high resolution optical mapping to confirm a large inversion in comparison to the other laboratory strains. Notably, DNA sequence comparison revealed the absence of several genes thought to be involved in biofilm formation, including antigen 43, waaSBOJYZUL for lipopolysaccharide (LPS) synthesis, and cpsB for curli synthesis. The first main difference we identified that likely affects biofilm formation is the presence of an IS3-like insertion sequence in front of the carbon storage regulator csrA gene. This insertion is located 86 bp upstream of the csrA start codon inside the - 35 region of P4 promoter and blocks the transcription from the sigma[32] and sigma[70] promoters P1-P3 located further upstream. The second is the presence of an IS5/IS1182 in front of the csgD gene. And finally, E. coli C encodes an additional sigma[70] subunit driven by the same IS3-like insertion sequence. Promoter analyses using GFP gene fusions provided insights into understanding this regulatory pathway in E. coli.

CONCLUSIONS: Biofilms are crucial for bacterial survival, adaptation, and dissemination in natural, industrial, and medical environments. Most laboratory strains of E. coli grown for decades in vitro have evolved and lost their ability to form biofilm, while environmental isolates that can cause infections and diseases are not safe to work with. Here, we show that the historic laboratory strain of E. coli C produces a robust biofilm and can be used as a model organism for multicellular bacterial research. Furthermore, we ascertained the full genomic sequence of this classic strain, which provides for a base level of characterization and makes it useful for many biofilm-based applications.}, } @article {pmid31638894, year = {2019}, author = {Di Domenico, EG and Rimoldi, SG and Cavallo, I and D'Agosto, G and Trento, E and Cagnoni, G and Palazzin, A and Pagani, C and Romeri, F and De Vecchi, E and Schiavini, M and Secchi, D and Antona, C and Rizzardini, G and Dichirico, RB and Toma, L and Kovacs, D and Cardinali, G and Gallo, MT and Gismondo, MR and Ensoli, F}, title = {Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {228}, pmid = {31638894}, issn = {1471-2180}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacteria/*classification/*drug effects/isolation & purification ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial ; Endocarditis/drug therapy/*microbiology/surgery ; Endocarditis, Bacterial/*diagnosis/drug therapy/surgery ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Phylogeny ; Treatment Outcome ; }, abstract = {BACKGROUND: Infective endocarditis (IE) is associated with high rates of mortality. Prolonged treatments with high-dose intravenous antibiotics often fail to eradicate the infection, frequently leading to high-risk surgical intervention. By providing a mechanism of antibiotic tolerance, which escapes conventional antibiotic susceptibility profiling, microbial biofilm represents a key diagnostic and therapeutic challenge for clinicians. This study aims at assessing a rapid biofilm identification assay and a targeted antimicrobial susceptibility profile of biofilm-growing bacteria in patients with IE, which were unresponsive to antibiotic therapy.

RESULTS: Staphylococcus aureus was the most common isolate (50%), followed by Enterococcus faecalis (25%) and Streptococcus gallolyticus (25%). All microbial isolates were found to be capable of producing large, structured biofilms in vitro. As expected, antibiotic treatment either administered on the basis of antibiogram or chosen empirically among those considered first-line antibiotics for IE, including ceftriaxone, daptomycin, tigecycline and vancomycin, was not effective at eradicating biofilm-growing bacteria. Conversely, antimicrobial susceptibility profile of biofilm-growing bacteria indicated that teicoplanin, oxacillin and fusidic acid were most effective against S. aureus biofilm, while ampicillin was the most active against S. gallolyticus and E. faecalis biofilm, respectively.

CONCLUSIONS: This study indicates that biofilm-producing bacteria, from surgically treated IE, display a high tolerance to antibiotics, which is undetected by conventional antibiograms. The rapid identification and antimicrobial tolerance profiling of biofilm-growing bacteria in IE can provide key information for both antimicrobial therapy and prevention strategies.}, } @article {pmid31637837, year = {2020}, author = {Røder, HL and Olsen, NMC and Whiteley, M and Burmølle, M}, title = {Unravelling interspecies interactions across heterogeneities in complex biofilm communities.}, journal = {Environmental microbiology}, volume = {22}, number = {1}, pages = {5-16}, doi = {10.1111/1462-2920.14834}, pmid = {31637837}, issn = {1462-2920}, support = {10098//Villum Fonden/International ; }, mesh = {*Biofilms ; Environmental Microbiology ; Microbial Interactions/*physiology ; }, abstract = {The importance of microbial biofilms has been well-recognized for several decades, and focus is now shifting towards investigating multispecies biofilm communities rather than mono- or dual-species biofilms. Therefore, the demand for techniques that provide a sufficient amount of information at adequate resolution is increasing. One major challenge for multispecies studies is that diversity and spatial organization often lead to a high degree of spatial and chemical heterogeneity. Many current approaches do not account for such heterogeneity and therefore only provide average information (-omics techniques in particular), which could obscure important information about the community. Here, we bring attention to the issues of heterogeneity when analysing synthetic multi-species biofilms, in vitro, and the importance of multi-scale approaches. We provide an overview of current and newer approaches that can be applied to biofilm communities, in order to elucidate interactions at the appropriate scale.}, } @article {pmid31637462, year = {2019}, author = {Birarda, G and Delneri, A and Lagatolla, C and Parisse, P and Cescutti, P and Vaccari, L and Rizzo, R}, title = {Multi-technique microscopy investigation on bacterial biofilm matrices: a study on Klebsiella pneumoniae clinical strains.}, journal = {Analytical and bioanalytical chemistry}, volume = {411}, number = {27}, pages = {7315-7325}, doi = {10.1007/s00216-019-02111-7}, pmid = {31637462}, issn = {1618-2650}, support = {FRA15//University of Trieste/ ; }, mesh = {Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism/ultrastructure ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/chemistry/*physiology/ultrastructure ; Microscopy, Atomic Force ; Microscopy, Confocal ; Spectrophotometry, Infrared ; }, abstract = {Biofilms are communities of bacteria living embedded in a highly hydrated matrix composed of polysaccharides, proteins, and extracellular DNA. This life style confers numerous advantages to bacteria including protection against external threats. However, they also contribute to increase bacterial resistance against antimicrobials, an issue particularly relevant in dangerous infections. Due to the complexity of the matrix, few information is present in the literature on details of its architecture including the spatial distribution of the macromolecular components which might give hints on the way the biofilm scaffold is built up by bacteria. In this study, we investigated the possibility to combine well-established microbiological procedures with advanced microscopies to get information on composition and distribution of the macromolecular components of biofilm matrices. To this, confocal microscopy, diffraction-limited infrared (IR) spectral imaging, and atomic force microscopy (AFM) were used to explore biofilm produced by a clinical strain of Klebsiella pneumoniae. IR imaging permitted to have clues on how the biofilm grows and spreads on surfaces, and the local distribution of the components within it. Through the analysis of the pure component spectra, it was possible to assess the chemical and structural composition of the saccaridic matrix, confirming the data obtained by NMR. It was also possible to follow the time course of biofilm from 6 up to 48 h when the biofilm grew into a 3-dimensional multi-layered structure, characteristic of colonies of bacteria linked together by a complex matrix. In addition, nanoFTIR and AFM investigations allowed the estimation of biofilm growth in the vertical direction and the morphological analysis of bacterial colonies at different time points and the evaluation of the chemical composition at the nanoscale.}, } @article {pmid31635733, year = {2020}, author = {Jung, J and Bae, Y and Kwan Cho, Y and Ren, X and Sun, Y}, title = {Structural insights into conformation of amphiphilic quaternary ammonium chitosans to control fungicidal and anti-biofilm functions.}, journal = {Carbohydrate polymers}, volume = {228}, number = {}, pages = {115391}, doi = {10.1016/j.carbpol.2019.115391}, pmid = {31635733}, issn = {1879-1344}, mesh = {Animals ; Antifungal Agents/*chemistry ; Biocompatible Materials/chemistry ; Biofilms/*drug effects ; Candida albicans/drug effects/physiology ; Cell Line ; Chitosan/*chemistry ; Molecular Conformation ; Quaternary Ammonium Compounds/*chemistry ; }, abstract = {Fungal biofilm formation is an emerging problem in a wide range of health-related applications. This study aims to design and synthesize amphiphilic quaternary ammonium chitosans (AQACs) that could bind onto fungal biofilms to kill adherent fungal cells, and establish their structural/fungicidal activity relationships. AQACs with different hydrophobic alkyl chain length (C4, C8, and C12) were synthesized by quaternization of 3-bromopropionic acid with the corresponding tertiary amines, followed by reacting with chitosan using the EDC/NHS chemistry. The new AQACs were soluble in water, yet formed self-aggregates in the solution with different sizes. In antifungal tests against free-floating Candida albicans, shorter alkyl chains (C4) in the AQACs resulted in the most potent fungicidal effect. However, in the treatment of Candida biofilms formed on solid surfaces, AQACs with longer alkyl chains (C8 and C12) were much more effective than their shorter chain counterpart (C4). The effects of alkyl chain self-aggregation on the opposite trend in fungicidal and anti-biofilm activities were discussed. All the AQACs showed excellent cytocompatibility with mammalian cells.}, } @article {pmid31634700, year = {2020}, author = {Sun, Y and Lang, Y and Yan, Z and Wang, L and Zhang, Z}, title = {High-throughput sequencing analysis of marine pioneer surface-biofilm bacteria communities on different PDMS-based coatings.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {185}, number = {}, pages = {110538}, doi = {10.1016/j.colsurfb.2019.110538}, pmid = {31634700}, issn = {1873-4367}, mesh = {Biodiversity ; *Biofilms ; Coated Materials, Biocompatible/*chemistry ; Dimethylpolysiloxanes/*chemistry ; High-Throughput Nucleotide Sequencing/*methods ; Molecular Sequence Annotation ; Nanotubes, Carbon/chemistry ; Phylogeny ; Seawater/*microbiology ; Surface Properties ; }, abstract = {Marine biofilms, the attachment of marine microorganisms on artificial surfaces in natural seawater, play critical roles in the development of marine biofouling, which pave ways for the settlement and colonization of sessile invertebrate larvae. Despite the excellent microbe-inhibitory effect of polydimethylsiloxane (PDMS)-based coatings, marine bacteria could still attach to surfaces and form natural biofilms. However, there is little information available on the common structural features of pioneer surface-biofilm bacteria (PSB) communities on different PDMS-based coatings with regard to their compositions, distributions and diversity. Herein, the present study aims to explore the compositional and structural features of the PSB communities on different PDMS-based coatings using 16S rRNA gene amplicon sequencing in terms of the taxonomic structures at phylum, family and genus level. The results revealed the PSB communities on different PDMS-based coatings possessed high similarities in compositional, structural and diversity features, but varied greatly in relative abundance and distributions. Proteobacteria was the most diverse and overwhelming phylum in biofilms formed on all PDMS-based coatings, followed by Cyanobacteria. In addition, the decreased abundance of Proteobacteria and the increased abundance of Cyanobacteria on the carbon nanotubes (CNTs)-modifed PDMS composites (CPCs) may contribute to their differential anti-biofouling effect against the colonization of juvenile macrofoulers.}, } @article {pmid31632948, year = {2019}, author = {Walsh, DJ and Livinghouse, T and Goeres, DM and Mettler, M and Stewart, PS}, title = {Antimicrobial Activity of Naturally Occurring Phenols and Derivatives Against Biofilm and Planktonic Bacteria.}, journal = {Frontiers in chemistry}, volume = {7}, number = {}, pages = {653}, pmid = {31632948}, issn = {2296-2646}, abstract = {Biofilm-forming bacteria present formidable challenges across diverse settings, and there is a need for new antimicrobial agents that are both environmentally acceptable and relatively potent against microorganisms in the biofilm state. The antimicrobial activity of three naturally occurring, low molecular weight, phenols, and their derivatives were evaluated against planktonic and biofilm Staphylococcus epidermidis and Pseudomonas aeruginosa. The structure activity relationships of eugenol, thymol, carvacrol, and their corresponding 2- and 4-allyl, 2-methallyl, and 2- and 4-n-propyl derivatives were evaluated. Allyl derivatives showed a consistent increased potency with both killing and inhibiting planktonic cells but they exhibited a decrease in potency against biofilms. This result underscores the importance of using biofilm assays to develop structure-activity relationships when the end target is biofilm.}, } @article {pmid31632023, year = {2019}, author = {Fang, JY and Lin, YK and Wang, PW and Alalaiwe, A and Yang, YC and Yang, SC}, title = {The Droplet-Size Effect Of Squalene@cetylpyridinium Chloride Nanoemulsions On Antimicrobial Potency Against Planktonic And Biofilm MRSA.}, journal = {International journal of nanomedicine}, volume = {14}, number = {}, pages = {8133-8147}, pmid = {31632023}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cations ; Cetylpyridinium/*pharmacology ; Emulsions ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*physiology ; Micelles ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry/ultrastructure ; Plankton/*drug effects ; Proteomics ; Squalene/*pharmacology ; }, abstract = {BACKGROUND: It is important to explore the interaction between antibacterial nanoparticles and microbes for understanding bactericidal activity and developing novel applications. It is possible that the nanoparticulate size can govern the antibacterial potency.

PURPOSE: The purpose of this study was to evaluate the antimicrobial and antibiofilm properties of cetylpyridinium chloride (CPC)-decorated nanoemulsions against methicillin-resistant Staphylococcus aureus (MRSA).

METHODS: The droplet size could be adjusted by varying the percentage of squalene, the main ingredient of the oily core.

RESULTS: We fabricated cationic nanoemulsions of three different sizes, 55, 165, and 245 nm. The nanoemulsions showed greater storage stability than the self-assembled CPC micelles. The tested nanoemulsions exhibited more antimicrobial activity against Gram-positive bacteria than Gram-negative bacteria and fungi. The killing of MRSA was mainly induced by direct cell-membrane damage. This rupture led to the leakage of cytoplasmic DNA and proteins. The nanoemulsions might also degrade the DNA helix and disturb protein synthesis. The proteomic analysis indicated the significant downregulation of DNA-directed RNA polymerase (RNAP) subunits β and β'. The antibacterial effect of nanoemulsions increased with decreasing droplet size in the biofilm MRSA but not planktonic MRSA. The small-sized nanoemulsions had potent antibiofilm activity that showed a colony-forming unit (CFU) reduction of 10-fold compared with the control. The loss of total DNA concentration also negatively correlated with the nanoemulsion size.

CONCLUSION: The present report established a foundation for the development of squalene@CPC nanosystems against drug-resistant S. aureus.}, } @article {pmid31631801, year = {2020}, author = {Sun, F and Yuan, Q and Wang, Y and Cheng, L and Li, X and Feng, W and Xia, P}, title = {Sub-minimum inhibitory concentration ceftazidime inhibits Escherichia coli biofilm formation by influencing the levels of the ibpA gene and extracellular indole.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {32}, number = {1}, pages = {7-14}, doi = {10.1080/1120009X.2019.1678913}, pmid = {31631801}, issn = {1973-9478}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms ; Ceftazidime/*pharmacology ; Escherichia coli/*physiology ; Escherichia coli Proteins/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Heat-Shock Proteins/*drug effects ; Indoles/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Escherichia coli is a common pathogen of bacterial biofilm infections. Sub-minimum inhibitory concentration ceftazidime (sub-MIC CAZ) could inhibit the biofilm formation of E. coli. Deletion of the ibpAB genes could increase the extracellular indole concentration of E. coli and then inhibit biofilm formation. Therefore, we speculated that sub-MIC CAZ might inhibit biofilm formation via ibpAB. In this study, the results showed that sub-MIC CAZ could significantly inhibit biofilm formation, swimming motility and the expression of the ibpA gene, while it could increase the expression of tnaA gene and extracellular indole concentration. Knockout of the ibpA gene resulted in a decrease in biofilm formation and swimming motility and an increase in the indole concentration. When treated with sub-MIC CAZ, the tnaA gene expression, indole concentration, biofilm formation and swimming motility of MG1655 ΔibpA were similar to those of the control group. The results indicated that sub-MIC CAZ might inhibit the biofilm formation of E. coli by increasing the extracellular indole concentration and downregulating the ibpA gene.}, } @article {pmid31631600, year = {2019}, author = {Pu, QK and Liu, SJ and Huang, H and Xiong, JF and Zhnang, L and Fang, Z and Wang, C}, title = {[Sterilization Effect of an Atmospheric Low Temperature Plasma Jet on Candida albicans Biofilm].}, journal = {Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition}, volume = {50}, number = {3}, pages = {339-343}, pmid = {31631600}, issn = {1672-173X}, mesh = {*Biofilms ; Candida albicans/*drug effects ; Cold Temperature ; Plasma Gases/*pharmacology ; Reproducibility of Results ; *Sterilization ; }, abstract = {OBJECTIVE: To evaluate the sterilization effect of new designed atmospheric low temperature plasma jet on Candida albicans (C. albicans) biofilm.

METHODS: C. albicans was grown into the logarithmic phase, and then was added to polystyrene 24-well microtitre plate. The amount of germs were calculated by viable plate counting to determine the reproducibility of each biofilm well. The germs in biofilm were treated by plasma for different exposure time and then the survived germs were quantified by plate counting, the dead cells were determined by staining the biofilm with propidium iodide (PI), and the ultrastructural changes of the germs in biofilm were observed by transmission electron microscopy (TEM).

RESULTS: When incubated for 72 h, germs tightly polymerized and classical mature biofilm were formed. This atmospheric low temperature plasma jet could inactivate C. albicans biofilm within a short exposure time. C. albicans were 90% inactivated when treated 20 s and 55 s of plasma treatment reduced bacteria populations to undetectable levels. With the increase of treatment time, enlarged fluorescent positive area appeared, and more bacteria died with the extending of exposure. The TEM scanning results showed that the new plasma jet inactivated C. albicans biofilm mainly via disrupting cell envelopes and then leading the release of cellular components, thus resulting in loss of cell viability.

CONCLUSION: Plasma generated from atmospheric low temperature plasma jet could damage the cell structure of C. albicans and efficiently sterilize C. albicans biofilm.}, } @article {pmid31630921, year = {2020}, author = {Evangelista, SS and Guimaraes, NR and Garcia, NB and Santos, SGD and Oliveira, AC}, title = {Effectiveness of manual versus automated cleaning on Staphylococcus epidermidis biofilm removal from the surface of surgical instruments.}, journal = {American journal of infection control}, volume = {48}, number = {3}, pages = {267-274}, doi = {10.1016/j.ajic.2019.08.024}, pmid = {31630921}, issn = {1527-3296}, mesh = {Automation/methods ; Bacterial Adhesion/*drug effects ; Bacterial Load/drug effects ; Biofilms/*drug effects ; Disinfection/*methods ; Environmental Restoration and Remediation/*methods ; Staphylococcal Infections/microbiology/*prevention & control ; Staphylococcus epidermidis/*drug effects ; Surgical Instruments/*microbiology ; }, abstract = {BACKGROUND: Biofilm removal is a challenge during surgical instrument processing. We analyzed the time required for Staphylococcus epidermidis to form biofilms on surgical instruments, and how cleaning methods removed them.

METHODS: Different areas (ratchet, shank, and jaw) of straight crile forceps were contaminated by soaking in Tryptic Soy Broth containing 10[6] colony forming units (CFU)/mL of S epidermidis for 1, 2, 4, 6, 8, and 12 hours. S epidermidis adhesion and removal, after manual or automated ultrasonic cleaning, was evaluated by microbiological culture and scanning electron microscopy.

RESULTS: Microbial load increased with time (10[1]-10[2] CFU/cm[2] after 1 hour; 10[4] CFU/cm[2] after 12 hours). Exopolysaccharide was detected after 2 hours and gradually increased thereafter. Bacterial load was reduced by 1-2 log10 after manual cleaning and 1-3 log10 after automated cleaning, but biofilms were not completely eliminated. In general, bacterial load was lower in shank fragments. This difference was significant at 6 hours.

CONCLUSIONS: Rapid adhesion of S epidermidis and exopolysaccharide formation was observed on surgical instruments. Automated cleaning was more effective than manual cleaning, but neither method removed biofilms completely. The precleaning conditions and the forceps design are critical factors in processing quality.}, } @article {pmid31630525, year = {2019}, author = {Cao, Y and Jana, S and Bowen, L and Tan, X and Liu, H and Rostami, N and Brown, J and Jakubovics, NS and Chen, J}, title = {Hierarchical Rose Petal Surfaces Delay the Early-Stage Bacterial Biofilm Growth.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {35}, number = {45}, pages = {14670-14680}, doi = {10.1021/acs.langmuir.9b02367}, pmid = {31630525}, issn = {1520-5827}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Microbial Sensitivity Tests ; Particle Size ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Pseudomonas aeruginosa/cytology/*drug effects/growth & development ; Rosa/*chemistry ; Staphylococcus epidermidis/cytology/*drug effects/growth & development ; Surface Properties ; }, abstract = {A variety of natural surfaces exhibit antibacterial properties; as a result, significant efforts in the past decade have been dedicated toward fabrication of biomimetic surfaces that can help control biofilm growth. Examples of such surfaces include rose petals, which possess hierarchical structures like the micropapillae measuring tens of microns and nanofolds that range in the size of 700 ± 100 nm. We duplicated the natural structures on rose petal surfaces via a simple UV-curable nanocasting technique and tested the efficacy of these artificial surfaces in preventing biofilm growth using clinically relevant bacteria strains. The rose petal-structured surfaces exhibited hydrophobicity (contact angle (CA) ≈ 130.8° ± 4.3°) and high CA hysteresis (∼91.0° ± 4.9°). Water droplets on rose petal replicas evaporated following the constant contact line mode, indicating the likely coexistence of both Cassie and Wenzel states (Cassie-Baxter impregnating the wetting state). Fluorescence microscopy and image analysis revealed the significantly lower attachment of Staphylococcus epidermidis (86.1 ± 6.2% less) and Pseudomonas aeruginosa (85.9 ± 3.2% less) on the rose petal-structured surfaces, compared with flat surfaces over a period of 2 h. An extensive biofilm matrix was observed in biofilms formed by both species on flat surfaces after prolonged growth (several days), but was less apparent on rose petal-biomimetic surfaces. In addition, the biomass of S. epidermidis (63.2 ± 9.4% less) and P. aeruginosa (76.0 ± 10.0% less) biofilms were significantly reduced on the rose petal-structured surfaces, in comparison to the flat surfaces. By comparing P. aeruginosa growth on representative unitary nanopillars, we demonstrated that hierarchical structures are more effective in delaying biofilm growth. The mechanisms are two-fold: (1) the nanofolds across the hemispherical micropapillae restrict initial attachment of bacterial cells and delay the direct contact of cells via cell alignment and (2) the hemispherical micropapillae arrays isolate bacterial clusters and inhibit the formation of a fibrous network. The hierarchical features on rose petal surfaces may be useful for developing strategies to control biofilm formation in medical and industrial contexts.}, } @article {pmid31630018, year = {2020}, author = {Liu, C and Song, D and Zhang, W and He, Q and Huangfu, X and Sun, S and Sun, Z and Cheng, W and Ma, J}, title = {Constructing zwitterionic polymer brush layer to enhance gravity-driven membrane performance by governing biofilm formation.}, journal = {Water research}, volume = {168}, number = {}, pages = {115181}, doi = {10.1016/j.watres.2019.115181}, pmid = {31630018}, issn = {1879-2448}, mesh = {Biofilms ; Filtration ; *Membranes, Artificial ; *Polymers ; Sewage ; }, abstract = {In this study, zwitterionic polymer brushes with controlled architecture were grafted on the surface of gravity-driven membrane (GDM) via surface-initiated reaction to impart antifouling property. A variety of membrane characterization techniques were conducted to demonstrate the successful functionalization of zwitterionic polymers on PVDF hollow fiber membrane. The membrane underwent 90 min of reaction time possessing strong hydrophilicity and high permeability was determined as the optimal modified membrane. Long-term GDM dynamic fouling experiments operated for 30 days using sewage wastewater as feed solution indicated zwitterionic polymer modified membrane exhibit excellent membrane fouling resistance thus enhanced stable flux. Confocal laser scanning microscopy (CLSM) imaging implied that zwitterionic polymer modification significantly inhibit the adsorption of extracellular polymeric substances (EPS) which dominates fouling propensity, resulting in the formation of a thin biofilm with high porosity under synthetic functions of foulants deposition and microbial activities. Interfacial free energy prediction affirmed the presence of zwitterionic functional layer on membrane surface could substantially decrease the interactions (e.g., electrostatic attractions and hydrophobic effects) between membrane and foulants, thereby reduced flux decline and high stable flux. Our study suggests surface hydrophilic functionalization shows promising potential for improving the performance of ultra-low pressure filtration.}, } @article {pmid31630005, year = {2020}, author = {Sebelemetja, M and Moeno, S and Patel, M}, title = {Anti-acidogenic, anti-biofilm and slow release properties of Dodonaea viscosa var. angustifolia flavone stabilized polymeric nanoparticles.}, journal = {Archives of oral biology}, volume = {109}, number = {}, pages = {104586}, doi = {10.1016/j.archoralbio.2019.104586}, pmid = {31630005}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Carriers ; Flavones/*pharmacology ; Nanoparticles ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Sapindaceae/*chemistry ; Streptococcus mutans ; }, abstract = {OBJECTIVE: Dental caries is caused by plaque associated oral bacteria including a pioneer species Streptococcus mutans. It has ability to form biofilm and produce acids in the oral cavity. Many oral hygiene products containing plant derived compounds have been investigated for their anti-S. mutans activity. Dodonaea viscosa var. angustifolia (DVA), has been found to have this property. However, beneficial concentrations are difficult to maintain in the oral cavity due to continual saliva flow which can be overcome using nanotechnology. The aim of this study was to investigate the anti-acidogenic, anti-biofilm and slow release properties of DVA derived flavone stabilized polymeric nanoparticles.

METHODS: Crude extract prepared from DVA leaves was fractionated to produce subfractions and the beneficial subfraction (F5.1) was obtained. Polymeric nanoparticles (PLGA-PEG) were prepared, stabilized with the DVA subfraction (F5.1/NPs) and characterized. Anti-S. mutans, anti-acidogenic and antibiofilm properties were determined. The subfraction release profile (substantivity) and cytotoxicity was determined. Results were analyzed using the Wilcoxon sum test (Mann-Whitney).

RESULTS: F5.1/NPs showed anti-S. mutans property (MIC 1.56 mg/ml). Subinhibitory concentrations of these nanoparticles significantly reduced the acid production in S. mutans (p < 0.01) and also reduced the biofilm formation by 92%. The retention and slow release of the beneficial compound was detected up to 12 h, reaching 0.1 mg/ml concentration at pH 7.4 after 4 h and at pH 5.5 after 5 h. IC50 of F5.1/NPs was 62.5 µg/ml.

CONCLUSION: the DVA flavone containing nanoparticles showed anticariogenic activity with improved substantivity. Therefore, they have potential for use to control dental caries.}, } @article {pmid31629797, year = {2020}, author = {Ohadi, M and Forootanfar, H and Dehghannoudeh, G and Eslaminejad, T and Ameri, A and Shakibaie, M and Adeli-Sardou, M}, title = {Antimicrobial, anti-biofilm, and anti-proliferative activities of lipopeptide biosurfactant produced by Acinetobacter junii B6.}, journal = {Microbial pathogenesis}, volume = {138}, number = {}, pages = {103806}, doi = {10.1016/j.micpath.2019.103806}, pmid = {31629797}, issn = {1096-1208}, mesh = {Acinetobacter/*metabolism ; Antimicrobial Cationic Peptides/*biosynthesis ; Bacteria/drug effects ; Biofilms/drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Fungi/drug effects ; Human Umbilical Vein Endothelial Cells/drug effects ; Humans ; Lipopeptides/*biosynthesis ; Microbial Sensitivity Tests ; Staphylococcus aureus/drug effects ; Surface-Active Agents/*metabolism ; }, abstract = {Lipopeptide biosurfactants (LPBs) are amphiphilic compounds produced by microorganisms exhibiting various biological activities. The main aim of the present study was to assess the in vitro antimicrobial, anti-biofilm, and cytotoxic effects of LPB produced by Acinetobacter junii (AjL). We determined AjL minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria as well as two fungal strains. Also, the anti-biofilm activity of AjL against the biofilm produced by clinically isolated bacterial strains was investigated. The AjL non-selectively showed activity against both Gram-positive and Gram-negative bacterial strains. The obtained results of the present study exhibited that the AjL in concentrations nearly below critical micelle concentration (CMC) has an effective antibacterial activity. It was found that the MIC values of AjL were lower than standard antifungal and it exhibited nearly 100% inhibition against Candida utilis. The attained results of the biofilm formation revealed that AjL disrupted the biofilm of Proteus mirabilis, Staphylococcus aureus, and Pseudomonas aeruginosa at 1250 μg/ml and 2500 μg/ml concentrations. The attained results of cytotoxic effect (determined by WST-1 assay) of the AjL revealed IC50 of 7.8 ± 0.4 mg/ml, 2.4 ± 0.5 mg/ml, and 5.7 ± 0.1 mg/ml, against U87, KB, and HUVEC cell lines, respectively. The results indicated that AjL has a potential application in the relatively new field of biomedicine.}, } @article {pmid31628906, year = {2020}, author = {Ghasemi, M and Jenkins, B and Doxey, AC and Sivaloganathan, S}, title = {A study of nitric oxide dynamics in a growing biofilm using a density dependent reaction-diffusion model.}, journal = {Journal of theoretical biology}, volume = {485}, number = {}, pages = {110053}, doi = {10.1016/j.jtbi.2019.110053}, pmid = {31628906}, issn = {1095-8541}, mesh = {*Biofilms ; Computer Simulation ; Diffusion ; *Models, Biological ; *Nitric Oxide ; }, abstract = {One of a number of critical roles played by NO· as a chemical weapon (generated by the immune system) is to neutralize pathogens. However, the virulence of pathogens depends on the production activity of reductants to detoxify NO·. Broad reactivity of NO· makes it complicated to predict the fate of NO· inside bacteria and its effects on the treatment of any infection. Here, we present a mathematical model of biofilm response to NO·, as a stressor. The model is comprised of a PDE system of highly nonlinear reaction-diffusion equations that we study in computer simulations to determine the positive and negative effects of key parameters on bacterial defenses against NO·. From the reported results, we conjecture that the oscillatory behavior of NO· under a microaerobic regime is a temporal phenomenon and does not give rise to a spatial pattern. It is also shown computationally that decreasing the initial size of the biofilm colony negatively impacts the functionality of reducing agents that deactivate NO·. Whereas nutrient deprivation results in the development of biofilms with heterogeneous structure, its effect on the activity of NO· reductants depends on the oxygen availability, biofilm size, and the amount of NO·.}, } @article {pmid31627387, year = {2019}, author = {Shetty, D and Abrahante, JE and Chekabab, SM and Wu, X and Korber, DR and Vidovic, S}, title = {Role of CpxR in Biofilm Development: Expression of Key Fimbrial, O-Antigen and Virulence Operons of Salmonella Enteritidis.}, journal = {International journal of molecular sciences}, volume = {20}, number = {20}, pages = {}, pmid = {31627387}, issn = {1422-0067}, mesh = {Bacterial Proteins/genetics/metabolism/*physiology ; Biofilms/*growth & development ; Fimbriae Proteins/genetics/metabolism/*physiology ; Gene Expression Profiling ; O Antigens/genetics/metabolism/*physiology ; Salmonella enteritidis/genetics/metabolism/*physiology ; Transcriptome ; Virulence Factors/*physiology ; }, abstract = {Salmonella Enteritidis is a non-typhoidal serovar of great public health significance worldwide. The RpoE sigma factor and CpxRA two-component system are the major regulators of the extracytoplasmic stress response. In this study, we found that the CpxR has highly significant, but opposite effects on the auto-aggregation and swarming motility of S. Enteritidis. Auto-aggregation was negatively affected in the ∆cpxR mutant, whereas the same mutant significantly out-performed its wild-type counterpart with respect to swarming motility, indicating that the CpxR plays a role in biofilm-associated phenotypes. Indeed, biofilm-related assays showed that the CpxR is of critical importance in biofilm development under both static (microtiter plate) and dynamic (flow cell) media flow conditions. In contrast, the RpoE sigma factor showed no significant role in biofilm development under dynamic conditions. Transcriptomic analysis revealed that the cpxR mutation negatively affected the constitutive expression of the operons critical for biosynthesis of O-antigen and adherence, but positively affected the expression of virulence genes critical for Salmonella-mediated endocytosis. Conversely, CpxR induced the expression of curli csgAB and fimbrial stdAC operons only during biofilm development and flagellar motAB and fliL operons exclusively during the planktonic phase, indicating a responsive biofilm-associated loop of the CpxR regulator.}, } @article {pmid31626589, year = {2019}, author = {Mangas, EL and Rubio, A and Álvarez-Marín, R and Labrador-Herrera, G and Pachón, J and Pachón-Ibáñez, ME and Divina, F and Pérez-Pulido, AJ}, title = {Pangenome of Acinetobacter baumannii uncovers two groups of genomes, one of them with genes involved in CRISPR/Cas defence systems associated with the absence of plasmids and exclusive genes for biofilm formation.}, journal = {Microbial genomics}, volume = {5}, number = {11}, pages = {}, pmid = {31626589}, issn = {2057-5858}, mesh = {Acinetobacter baumannii/*genetics ; Bacteria/genetics ; Bacterial Proteins/genetics ; Biofilms ; CRISPR-Cas Systems ; Clustered Regularly Interspaced Short Palindromic Repeats ; Genome, Bacterial/genetics ; Genomics ; Phylogeny ; Plasmids/*genetics ; }, abstract = {Acinetobacter baumannii is an opportunistic bacterium that causes hospital-acquired infections with a high mortality and morbidity, since there are strains resistant to virtually any kind of antibiotic. The chase to find novel strategies to fight against this microbe can be favoured by knowledge of the complete catalogue of genes of the species, and their relationship with the specific characteristics of different isolates. In this work, we performed a genomics analysis of almost 2500 strains. Two different groups of genomes were found based on the number of shared genes. One of these groups rarely has plasmids, and bears clustered regularly interspaced short palindromic repeat (CRISPR) sequences, in addition to CRISPR-associated genes (cas genes) or restriction-modification system genes. This fact strongly supports the lack of plasmids. Furthermore, the scarce plasmids in this group also bear CRISPR sequences, and specifically contain genes involved in prokaryotic toxin-antitoxin systems that could either act as the still little known CRISPR type IV system or be the precursors of other novel CRISPR/Cas systems. In addition, a limited set of strains present a new cas9-like gene, which may complement the other cas genes in inhibiting the entrance of new plasmids into the bacteria. Finally, this group has exclusive genes involved in biofilm formation, which would connect CRISPR systems to the biogenesis of these bacterial resistance structures.}, } @article {pmid31625519, year = {2019}, author = {Behzadpour, N and Akbari, N and Sattarahmady, N}, title = {Photothermal inactivation of methicillin-resistant Staphylococcus aureus: anti-biofilm mediated by a polypyrrole-carbon nanocomposite.}, journal = {IET nanobiotechnology}, volume = {13}, number = {8}, pages = {800-807}, pmid = {31625519}, issn = {1751-875X}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; *Biofilms/drug effects/growth & development/radiation effects ; Carbon/*chemistry/pharmacology/therapeutic use ; Coated Materials, Biocompatible/chemical synthesis/chemistry/therapeutic use ; Hot Temperature/*therapeutic use ; Humans ; Materials Testing ; Methicillin Resistance/drug effects/radiation effects ; *Methicillin-Resistant Staphylococcus aureus/drug effects/physiology/radiation effects ; Microbial Sensitivity Tests ; Microbial Viability/radiation effects ; Nanocomposites/chemistry/*therapeutic use ; Phototherapy/*methods ; Polymers/*chemistry/pharmacology/therapeutic use ; Pyrroles/*chemistry/pharmacology/therapeutic use ; Staphylococcal Infections/therapy ; }, abstract = {Widespread resistance to antibiotics amongst pathogens has become a tremendous challenge of high morbidity and mortality rates which increases the needs to exploring novel methods of treatment. An efficient antimicrobial procedure to root out pathogenic bacteria is photothermal therapy. In this study, antimicrobial effects of a polypyrrole-carbon nanocomposite (PPy-C) upon laser irradiation in order to destroy the pathogenic gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA) were assessed. The bacterial cells were incubated with 500, 750 and 1000 μg ml[-1] concentrations of PPy-C and irradiated with an 808-nm laser at a power density of 1.0 W cm[-2]. To indicate the biocompatibility and toxic effect of the nanocomposite without and with laser irradiation, the authors counted the number of CFUs and compared it to an untreated sample. Antibacterial mechanisms of PPy-C were assessed through temperature increment, reactive oxygen species production, and protein and DNA leakages. Photothermal heating assay showed that 26°C temperature increases in the presence of 1000 µg ml[-1] PPy-C led to >98% killing of MRSA. Furthermore, 20 min radiation of near-infrared light to PPy-C in different concentrations indicated destruction and reduction in the MRSA biofilm formation. Therefore, PPy-C was introduced as a photothermal absorber with a bactericidal effect in MRSA.}, } @article {pmid31625441, year = {2019}, author = {Bombarda, GF and Rosalen, PL and Paganini, ER and Garcia, MA and Silva, DR and Lazarini, JG and Freires, IA and Regasini, LO and Sardi, JC}, title = {Bioactive molecule optimized for biofilm reduction related to childhood caries.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {1207-1220}, doi = {10.2217/fmb-2019-0144}, pmid = {31625441}, issn = {1746-0921}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Cells, Cultured ; Chalcones/*pharmacology ; Dental Caries/drug therapy/microbiology ; Fibroblasts/drug effects/microbiology ; Gingiva/cytology/drug effects ; Humans ; Larva ; Microbial Sensitivity Tests ; Moths ; Phytochemicals/*pharmacology ; Streptococcus mutans/drug effects ; }, abstract = {Aim: To evaluate antimicrobial activity of a new nitrochalcone (NC-E08) against Candida albicans and Streptococcus mutans, and its toxicity. Materials & methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration/minimum fungicidal concentration (MFC) were determined against C. albicans and S. mutans, as well as antibiofilm potential and toxicity (human gingival fibroblast and Galleria mellonella). Infection and treatment were performed in G. mellonella. Results & conclusion: NC-E08 showed antimicrobial activity in C. albicans (MIC: 0.054 mM) and S. mutans (MIC: 0.013 mM); 10xMIC treatment reduced 4.0 log10 biofilms for both strains and there was a reduction in survival of mixed biofilms of C. albicans and S. mutans (6.0 and 4.0 log10, respectively). NC-E08 showed no cytotoxicity in human gingival fibroblast cells and G. mellonella. NC-E08 after larval infection protected them 90% (p < 0.05). Thus, is a promising one for the prevention and treatment of S. mutans and C. albicans infections.}, } @article {pmid31623950, year = {2020}, author = {Robertson, SN and Childs, PG and Akinbobola, A and Henriquez, FL and Ramage, G and Reid, S and Mackay, WG and Williams, C}, title = {Reduction of Pseudomonas aeruginosa biofilm formation through the application of nanoscale vibration.}, journal = {Journal of bioscience and bioengineering}, volume = {129}, number = {3}, pages = {379-386}, doi = {10.1016/j.jbiosc.2019.09.003}, pmid = {31623950}, issn = {1347-4421}, mesh = {*Biofilms ; Biomass ; Extracellular Matrix/metabolism ; Microscopy, Electron, Scanning ; Nanostructures ; Pseudomonas aeruginosa/*physiology ; Vibration ; }, abstract = {Bacterial biofilms pose a significant burden in both healthcare and industrial environments. With the limited effectiveness of current biofilm control strategies, novel or adjunctive methods in biofilm control are being actively pursued. Reported here, is the first evidence of the application of nanovibrational stimulation (nanokicking) to reduce the biofilm formation of Pseudomonas aeruginosa. Nanoscale vertical displacements (approximately 60 nm) were imposed on P. aeruginosa cultures, with a significant reduction in biomass formation observed at frequencies between 200 and 4000 Hz at 24 h. The optimal reduction of biofilm formation was observed at 1 kHz, with changes in the physical morphology of the biofilms. Scanning electron microscope imaging of control and biofilms formed under nanovibrational stimulation gave indication of a reduction in extracellular matrix (ECM). Quantification of the carbohydrate and protein components of the ECM was performed and showed a significant reduction at 24 h at 1 kHz frequency. To model the forces being exerted by nanovibrational stimulation, laser interferometry was performed to measure the amplitudes produced across the Petri dish surfaces. Estimated peak forces on each cell, associated with the nanovibrational stimulation technique, were calculated to be in the order of 10 pN during initial biofilm formation. This represents a potential method of controlling microbial biofilm formation in a number of important settings in industry and medical related processes.}, } @article {pmid31622708, year = {2020}, author = {Choi, M and Hasan, N and Cao, J and Lee, J and Hlaing, SP and Yoo, JW}, title = {Chitosan-based nitric oxide-releasing dressing for anti-biofilm and in vivo healing activities in MRSA biofilm-infected wounds.}, journal = {International journal of biological macromolecules}, volume = {142}, number = {}, pages = {680-692}, doi = {10.1016/j.ijbiomac.2019.10.009}, pmid = {31622708}, issn = {1879-0003}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/pharmacology ; Bandages ; Biofilms ; Cell Line ; Cell Survival ; Chitosan/*chemistry ; Collagen/drug effects ; Diabetes Mellitus, Experimental ; Drug Delivery Systems ; Drug Liberation ; Hydrogels/chemistry ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Mice ; Mice, Inbred ICR ; Nitric Oxide/*chemistry/pharmacology ; Wound Healing/*drug effects ; }, abstract = {Bacterial biofilms on wounds impair the healing process and often lead to chronic wounds. Chitosan is a well-known biopolymer with antimicrobial and anti-biofilm effects. S-nitrosoglutathione (GSNO) has been identified as a promising nitric oxide (NO) donor to defend against pathogenic biofilms and enhance wound healing activities. In this study, we prepared NO-releasing chitosan film (CS/NO film) and evaluated its anti-biofilm activity and in vivo wound healing efficacy against methicillin-resistant Staphylococcus aureus (MRSA) biofilm-infected wounds in diabetic mice. The in vitro release study showed sustained release of NO over 3 days in simulated wound fluid. The CS/NO film significantly enhanced antibacterial activity against MRSA by > 3 logs reduction in bacterial viability. Moreover, CS/NO film exhibited a 3-fold higher anti-biofilm activity than the control and CS film. In in vivo MRSA biofilm-infected wounds, the CS/NO film-treated group showed faster biofilm dispersal, wound size reduction, epithelialization rates, and collagen deposition than the untreated and CS film-treated groups. Therefore, the CS/NO film investigated in this study could be a promising approach for the treatment of MRSA biofilm-infected wounds.}, } @article {pmid31622331, year = {2019}, author = {Kobayashi, K and Ikemoto, Y}, title = {Biofilm-associated toxin and extracellular protease cooperatively suppress competitors in Bacillus subtilis biofilms.}, journal = {PLoS genetics}, volume = {15}, number = {10}, pages = {e1008232}, pmid = {31622331}, issn = {1553-7404}, mesh = {Anti-Bacterial Agents/biosynthesis ; Bacillus subtilis/*genetics/growth & development ; Bacterial Proteins/*genetics ; Bacterial Toxins/*genetics ; Biofilms/*growth & development ; Endopeptidases/genetics ; Gene Expression Regulation, Bacterial/genetics ; Mutation ; Operon/genetics ; }, abstract = {In nature, most bacteria live in biofilms where they compete with their siblings and other species for space and nutrients. Some bacteria produce antibiotics in biofilms; however, since the diffusion of antibiotics is generally hindered in biofilms by extracellular polymeric substances, i.e., the biofilm matrix, their function remains unclear. The Bacillus subtilis yitPOM operon is a paralog of the sdpABC operon, which produces the secreted peptide toxin SDP. Unlike sdpABC, yitPOM is induced in biofilms by the DegS-DegU two-component regulatory system. High yitPOM expression leads to the production of a secreted toxin called YIT. Expression of yitQ, which lies upstream of yitPOM, confers resistance to the YIT toxin, suggesting that YitQ is an anti-toxin protein for the YIT toxin. The alternative sigma factor SigW also contributes to YIT toxin resistance. In a mutant lacking yitQ and sigW, the YIT toxin specifically inhibits biofilm formation, and the extracellular neutral protease NprB is required for this inhibition. The requirement for NprB is eliminated by Δeps and ΔbslA mutations, either of which impairs production of biofilm matrix polymers. Overexpression of biofilm matrix polymers prevents the action of the SDP toxin but not the YIT toxin. These results indicate that, unlike the SDP toxin and many conventional antibiotics, the YIT toxin can pass through layers of biofilm matrix polymers to attack cells within biofilms with assistance from NprB. When the wild-type strain and the YIT-sensitive mutant were grown together on a solid medium, the wild-type strain formed biofilms that excluded the YIT-sensitive mutant. This observation suggests that the YIT toxin protects B. subtilis biofilms against competitors. Several bacteria are known to produce antibiotics in biofilms. We propose that some bacteria including B. subtilis may have evolved specialized antibiotics that can function within biofilms.}, } @article {pmid31621697, year = {2019}, author = {He, Y and Wan, X and Xiao, K and Lin, W and Li, J and Li, Z and Luo, F and Tan, H and Li, J and Fu, Q}, title = {Anti-biofilm surfaces from mixed dopamine-modified polymer brushes: synergistic role of cationic and zwitterionic chains to resist staphyloccocus aureus.}, journal = {Biomaterials science}, volume = {7}, number = {12}, pages = {5369-5382}, doi = {10.1039/c9bm01275c}, pmid = {31621697}, issn = {2047-4849}, mesh = {Animals ; Anti-Bacterial Agents/*chemical synthesis/chemistry/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Biofouling/prevention & control ; Cell Line ; Dopamine/*chemistry ; Drug Synergism ; Methacrylates/chemical synthesis/chemistry/pharmacology ; Mice ; Molecular Dynamics Simulation ; Quaternary Ammonium Compounds/chemical synthesis/chemistry/pharmacology ; Staphylococcus aureus/drug effects/*growth & development ; Surface Properties ; }, abstract = {Infections resulting from the attachment of bacteria and biofilm formation on the surface of medical implants give rise to a severe problem for medical device safety. Thus, the development of antibacterial materials that integrate bactericidal and antifouling properties is a promising approach to prevent biomaterial-associated infections. In this study, two types of dopamine-modified polymers, dopamine-terminated quaternary ammonium salt polymer (D-PQAs) with various lengths of N-alkyl chain (D-PQA4C, D-PQA8C, and D-PQA12C) and dopamine-terminated poly(sulfobetaine methacrylate) (D-PSBMA), were synthesized via atom transfer radical polymerization (ATRP). Mixed polymer brushes of D-PQAs and D-PSBMA with various ratios were well-integrated onto the surface of a silicon wafer via a facile mussel-inspired adhesion. We demonstrate that the synergistic antibacterial effect depends on both the ratio of the two components and the surface structures of the mixed polymer brushes, originating from the interactions between D-PQAs and D-PSBMA. The N-alkyl chain length of D-PQAs influenced the distribution and orientation of the alkyl chain on the mixed polymer brushes. A chart of the antibacterial efficiency of the mixed polymer brushes was obtained to reveal the synergistic role of their cationic and zwitterionic chains to resist S. aureus. The dominant amount of antifouling D-PSBMA with a minor amount of bactericidal D-PQAs with a short N-alkyl chain length facilitated the synergistic antibacterial effect. The selected polymer brushes (PSBMA/PQA4C-10%, PSBMA/PQA4C-30%, and PSBMA/PQA8C-10%) could effectively prevent biofilm formation by S. aureus for a long time, while having good biocompatibility. This work may provide a universal design strategy for the preparation of anti-biofilm and biocompatible surfaces for biomedical applications.}, } @article {pmid31621183, year = {2019}, author = {Hu, Y and Liu, X and Ren, ATM and Gu, JD and Cao, B}, title = {Optogenetic Modulation of a Catalytic Biofilm for the Biotransformation of Indole into Tryptophan.}, journal = {ChemSusChem}, volume = {12}, number = {23}, pages = {5142-5148}, doi = {10.1002/cssc.201902413}, pmid = {31621183}, issn = {1864-564X}, support = {MOE2017-T2-2-042//Ministry of Education - Singapore/ ; }, mesh = {*Biofilms ; Bioreactors ; Biotransformation ; Catalysis ; Culture Media ; Cyclic GMP/genetics/*metabolism ; Indoles/*metabolism ; Infrared Rays ; *Optogenetics ; Tryptophan/*biosynthesis ; }, abstract = {In green chemical synthesis, biofilms as biocatalysts have shown great promise. Efficient biofilm-mediated biocatalysis requires the modulation of biofilm formation. Optogenetic tools are ideal to control biofilms because light is noninvasive, easily controllable, and cost-efficient. In this study, a gene circuit responsive to near-infrared (NIR) light was used to modulate the cellular level of bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-GMP), a central regulator of the prokaryote biofilm lifestyle, which allowed the regulation of biofilm formation by using NIR light. The engineered biofilm was applied to catalyze the biotransformation of indole into tryptophan in submerged biofilm reactors and NIR-light-enhanced biofilm formation resulted in an approximately 30 % increase in tryptophan yield, which demonstrates the feasibility of the application of light to modulate the formation and performance of catalytic biofilms for chemical production. The c-di-GMP-targeted optogenetic approach to modulate catalytic biofilms showcases applications for biofilm-mediated biocatalysis.}, } @article {pmid31621139, year = {2020}, author = {Gowri, M and Jayashree, B and Jeyakanthan, J and Girija, EK}, title = {Sertraline as a promising antifungal agent: inhibition of growth and biofilm of Candida auris with special focus on the mechanism of action in vitro.}, journal = {Journal of applied microbiology}, volume = {128}, number = {2}, pages = {426-437}, doi = {10.1111/jam.14490}, pmid = {31621139}, issn = {1365-2672}, support = {PDF/2016/003088//Department of Science and Technology, Ministry of Science and Technology/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/growth & development/physiology ; Candidiasis/*microbiology ; Ergosterol/metabolism ; Humans ; Microbial Sensitivity Tests ; Sertraline/*pharmacology ; }, abstract = {AIM: The aim of this present study was to investigate the antifungal mechanism of sertraline against Candida auris (C. auris) and its effect on biofilm formation.

METHODS AND RESULTS: Sertraline, a repurposing drug with a history of human use for the treatment of depression was screened against three different isolates of C. auris, and was found to possess efficient antifungal activity. The antifungal activity of sertraline was further confirmed by killing kinetics assay and post-antifungal effect (PAFE). Sertraline inhibited C. auris yeast to hyphae conversion and further the inhibition of biofilm formation showed 71% inhibition upon treatment. Cell damage caused due to C. auris after treatment with sertraline was observed using SEM and cell membrane damage was ascertained using flow cytometry by Propidium Iodide (PI) uptake assay. The results of sorbitol protection assay and ergosterol effect assay suggested that sertraline did not affect the cell wall and did not act by binding to membrane ergosterol. The mechanism of action of sertraline against C. auris was understood through in silico docking studies that revealed the binding nature of sertraline to the sterol 14 alpha demethylase which is involved in ergosterol biosynthesis. Ergosterol that was quantified from treated cells showed a 5·5-fold decrease in ergosterol production.

CONCLUSION: Sertraline displayed promising antifungal activity against C. auris involved in candidiasis infection and the mechanism of action was predicted.

The results of this study can encourage for the development of new antifungal agents and can be promising antifungal agent against C. auris infection.}, } @article {pmid31621078, year = {2020}, author = {Wolf, DI and Vis, ML}, title = {Stream Algal Biofilm Community Diversity Along An Acid Mine Drainage Recovery Gradient Using Multimarker Metabarcoding.}, journal = {Journal of phycology}, volume = {56}, number = {1}, pages = {11-22}, doi = {10.1111/jpy.12935}, pmid = {31621078}, issn = {1529-8817}, mesh = {Biodiversity ; Biofilms ; *Diatoms ; *Ecosystem ; }, abstract = {In southeastern Ohio, active remediation of streams affected by Acid Mine Drainage (AMD) has proven to be successful for some streams, while others have not recovered based on macroinvertebrate assessment. In this study, biofilms were collected from three Moderately Impaired, three Recovered, and two Unimpaired streams. The biodiversity was characterized by metabarcoding using two universal barcode markers (16S and 18S) along with two algal specific markers (UPA and rbcL) and high-throughput amplicon sequencing. For each marker, the ordination of Bray-Curtis Index calculated from the total Amplicon Sequence Variants (ASVs) present in each stream showed the Unimpaired and Recovered streams clustered, while Moderately Impaired streams were more distant. Focusing on the algal ASVs, the Shannon index for the rbcL, and UPA markers showed significantly lower alpha diversity in Moderately Impaired streams compared to Unimpaired streams, but the Recovered streams were not significantly different from the other two stream categories. The two universal markers together captured all algal phyla providing an outline of the diversity, but the two algal specific markers produced a greater number of ASVs and taxonomic depth for algal taxa. Further examination of the UPA marker revealed a drastic decrease in relative abundance of diatoms in Moderately Impaired streams compared to Recovered and Unimpaired streams. Likewise, diatom genera identified in the rbcL data and indicative of stream water quality showed marked differences in relative abundance among stream categories. Although all markers were useful, the algal-specific UPA and rbcL contributed more insights into algal community differences among stream categories.}, } @article {pmid31618938, year = {2019}, author = {Zapién-Chavarría, KA and Plascencia-Terrazas, A and Venegas-Ortega, MG and Varillas-Torres, M and Rivera-Chavira, BE and Adame-Gallegos, JR and González-Rangel, MO and Nevárez-Moorillón, GV}, title = {Susceptibility of Multidrug-Resistant and Biofilm-Forming Uropathogens to Mexican Oregano Essential Oil.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31618938}, issn = {2079-6382}, support = {Fellowship No. 584251 for M.G.V.O.//Consejo Nacional de Ciencia y Tecnología/ ; Fellowship No. 597284 for M.V.T.//Consejo Nacional de Ciencia y Tecnología/ ; }, abstract = {Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have antimicrobial activity. Therefore, three Mexican oregano essential oils (two Lippia berlandieri Schauer and one Poliomintha longiflora) were tested for antimicrobial capacity against multidrug-resistant, biofilm-forming bacterial isolates. Clinical isolates from urinary tract infections were tested for antibiotic resistance. Multidrug-resistant isolates were evaluated for biofilm formation, and Mexican oregano antimicrobial effect was determined by the minimal inhibitory (CMI) and minimal bactericidal concentrations (CMB). The selected isolates were identified by molecular phylogenetic analysis. Sixty-one isolates were included in the study; twenty were characterized as multidrug-resistant and from those, six were strong biofilm formers. Three isolates were identified as Escherichia coli, two as Pseudomonas aeruginosa and one as Enterococcus faecalis based on the phylogenetic analysis of 16 S rRNA gene sequences. The antimicrobial effect was bactericidal; E. faecalis was the most susceptible (<200 mg/L CMI/CMB), and P. aeruginosa was the most resistant (>2,000 mg/L CMI/CMB). There was a range of 500-1000 mg/L (CMI/CMB) for the E. coli isolates. Mexican oregano essential oils demonstrated antimicrobial efficacy against multidrug-resistant clinical isolates.}, } @article {pmid31618903, year = {2019}, author = {Pandey, VK and Srivastava, KR and Ajmal, G and Thakur, VK and Gupta, VK and Upadhyay, SN and Mishra, PK}, title = {Differential Susceptibility of Catheter Biomaterials to Biofilm-Associated Infections and Their Remedy by Drug-Encapsulated Eudragit RL100 Nanoparticles.}, journal = {International journal of molecular sciences}, volume = {20}, number = {20}, pages = {}, pmid = {31618903}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; *Biocompatible Materials ; Biofilms/*drug effects ; Catheters/*microbiology ; Drug Liberation ; Escherichia coli/drug effects/physiology ; Humans ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry/ultrastructure ; }, abstract = {Biofilms are the cause of major bacteriological infections in patients. The complex architecture of Escherichia coli (E. coli) biofilm attached to the surface of catheters has been studied and found to depend on the biomaterial's surface properties. The SEM micrographs and water contact angle analysis have revealed that the nature of the surface affects the growth and extent of E. coli biofilm formation. In vitro studies have revealed that the Gram-negative E. coli adherence to implanted biomaterials takes place in accordance with hydrophobicity, i.e., latex > silicone > polyurethane > stainless steel. Permanent removal of E. coli biofilm requires 50 to 200 times more gentamicin sulfate (G-S) than the minimum inhibitory concentration (MIC) to remove 90% of E. coli biofilm (MBIC90). Here, in vitro eradication of biofilm-associated infection on biomaterials has been done by Eudragit RL100 encapsulated gentamicin sulfate (E-G-S) nanoparticle of range 140 nm. It is 10-20 times more effective against E. coli biofilm-associated infections eradication than normal unentrapped G-S. Thus, Eudragit RL100 mediated drug delivery system provides a promising way to reduce the cost of treatment with a higher drug therapeutic index.}, } @article {pmid31617725, year = {2020}, author = {Altube, MJ and Martínez, MMB and Malheiros, B and Maffía, PC and Barbosa, LRS and Morilla, MJ and Romero, EL}, title = {Fast Biofilm Penetration and Anti-PAO1 Activity of Nebulized Azithromycin in Nanoarchaeosomes.}, journal = {Molecular pharmaceutics}, volume = {17}, number = {1}, pages = {70-83}, doi = {10.1021/acs.molpharmaceut.9b00721}, pmid = {31617725}, issn = {1543-8392}, mesh = {A549 Cells ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Azithromycin/administration & dosage/*pharmacology/toxicity ; Biofilms/*drug effects ; Cell Line, Tumor ; Cryoelectron Microscopy ; Epithelial Cells/drug effects ; Halorubrum/*chemistry ; Humans ; Lipids/chemistry ; Liposomes ; Microbial Sensitivity Tests ; Mucins/metabolism ; Nanocapsules/*chemistry/ultrastructure ; Phospholipids/chemistry ; Pseudomonas aeruginosa/*drug effects/enzymology ; X-Ray Diffraction ; }, abstract = {Azithromycin (AZ) is a broad-spectrum antibiotic with anti-inflammatory and antiquorum sensing activity against biofilm forming bacteria such as Pseudomonas aeruginosa. AZ administered by oral or parenteral routes, however, neither efficiently accesses nor remains in therapeutic doses inside pulmonary biofilm depths. Instead, inhaled nanocarriers loaded with AZ may revert the problem of low accessibility and permanence of AZ into biofilms, enhancing its antimicrobial activity. The first inhalable nanovesicle formulation of AZ, nanoarchaeosome-AZ (nanoARC-AZ), is here presented. NanoARC prepared with total polar archaeolipids (TPAs), rich in 2,3-di-O-phytanyl-sn-glycero-1-phospho-(3'-sn-glycerol-1'-methylphosphate) (PGP-Me) from Halorubrum tebenquichense archaebacteria, consisted of ∼180 nm-diameter nanovesicles, loaded with 0.28 w/w AZ/TPA. NanoARC-AZ displayed lower minimal inhibitory concentration and minimal bactericidal concentration, higher preformed biofilm disruptive, and anti-PAO1 activity in biofilms than AZ. NanoARC penetrated and disrupted the structure of the PAO1 biofilm within only 1 h. Two milliliters of 15 μg/mL AZ nanoARC-AZ nebulized for 5 min rendered AZ doses compatible with in vitro antibacterial activity. The strong association between AZ and the nanoARC bilayer, combined with electrostatic attraction and trapping into perpendicular methyl groups of archaeolipids, as determined by Laurdan fluorescence anisotropy, generalized polarization, and small-angle X-ray scattering, was critical to stabilize during storage and endure shear forces of nebulization. NanoARC-AZ was noncytotoxic on A549 cells and human THP-1-derived macrophages, deserving further preclinical exploration as enhancers of AZ anti-PAO1 activity.}, } @article {pmid31616604, year = {2019}, author = {Chinnici, J and Yerke, L and Tsou, C and Busarajan, S and Mancuso, R and Sadhak, ND and Kim, J and Maddi, A}, title = {Candida albicans cell wall integrity transcription factors regulate polymicrobial biofilm formation with Streptococcus gordonii.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e7870}, pmid = {31616604}, issn = {2167-8359}, abstract = {Polymicrobial biofilms play important roles in oral and systemic infections. The oral plaque bacterium Streptococcus gordonii is known to attach to the hyphal cell wall of the fungus Candida albicans to form corn-cob like structures in biofilms. However, the role of C. albicans in formation of polymicrobial biofilms is not completely understood. The objective of this study was to determine the role of C. albicans transcription factors in regulation of polymicrobial biofilms and antibiotic tolerance of S. gordonii. The proteins secreted by C. albicans and S. gordonii in mixed planktonic cultures were determined using mass spectrometry. Antibiotic tolerance of S. gordonii to ampicillin and erythromycin was determined in mixed cultures and mixed biofilms with C. albicans. Additionally, biofilm formation of S. gordonii with C. albicans knock-out mutants of 45 transcription factors that affect cell wall integrity, filamentous growth and biofilm formation was determined. Furthermore, these mutants were also screened for antibiotic tolerance in mixed biofilms with S. gordonii. Analysis of secreted proteomes resulted in the identification of proteins being secreted exclusively in mixed cultures. Antibiotic testing showed that S. gordonii had significantly increased survival in mixed planktonic cultures with antibiotics as compared to single cultures. C. albicans mutants of transcription factors Sfl2, Brg1, Leu3, Cas5, Cta4, Tec1, Tup1, Rim101 and Efg1 were significantly affected in mixed biofilm formation. Also mixed biofilms of S. gordonii with mutants of C. albicans transcription factors, Tec1 and Sfl2, had significantly reduced antibiotic tolerance as compared to control cultures. Our data indicates that C. albicans may have an important role in mixed biofilm formation as well as antibiotic tolerance of S. gordonii in polymicrobial biofilms. C. albicans may play a facilitating role than being just an innocent bystander in oral biofilms and infections.}, } @article {pmid31611856, year = {2019}, author = {Peng, P and Baldry, M and Gless, BH and Bojer, MS and Espinosa-Gongora, C and Baig, SJ and Andersen, PS and Olsen, CA and Ingmer, H}, title = {Effect of Co-inhabiting Coagulase Negative Staphylococci on S. aureus agr Quorum Sensing, Host Factor Binding, and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2212}, pmid = {31611856}, issn = {1664-302X}, abstract = {Staphylococcus aureus is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs by methicillin resistant S. aureus has become a problem with increasing numbers of humans being infected by livestock strains. In S. aureus colonization and virulence factor expression is controlled by the agr quorum sensing system, which responds to and is activated by self-generated, autoinducing peptides (AIPs). AIPs are also produced by coagulase negative staphylococci (CoNS) commonly found as commensals in both humans and animals, and interestingly, some of these inhibit S. aureus agr activity. Here, we have addressed if cross-communication occurs between S. aureus and CoNS strains isolated from pig nares, and if so, how properties such as host factor binding and biofilm formation are affected. From 25 pig nasal swabs we obtained 54 staphylococcal CoNS isolates belonging to 8 different species. Of these, none were able to induce S. aureus agr as monitored by reporter gene fusions to agr regulated genes but a number of agr-inhibiting species were identified including Staphylococcus hyicus, Staphylococcus simulans, Staphylococcus arlettae, Staphylococcus lentus, and Staphylococcus chromogenes. After establishing that the inhibitory activity was mediated via AgrC, the receptor of AIPs, we synthesized selective AIPs to explore their effect on adhesion of S. aureus to fibronectin, a host factor involved in S. aureus colonization. Here, we found that the CoNS AIPs did not affect adhesion of S. aureus except for strain 8325-4. When individual CoNS strains were co-cultured together with S. aureus we observed variable degrees of biofilm formation which did not correlate with agr interactions. Our results show that multiple CoNS species can be isolated from pig nares and that the majority of these produce AIPs that inhibit S. aureus agr. Further they show that the consequences of the interactions between CoNS and S. aureus are complex and highly strain dependent.}, } @article {pmid31611714, year = {2019}, author = {Tam, A and Green, JEF and Balasuriya, S and Tek, EL and Gardner, JM and Sundstrom, JF and Jiranek, V and Binder, BJ}, title = {A thin-film extensional flow model for biofilm expansion by sliding motility.}, journal = {Proceedings. Mathematical, physical, and engineering sciences}, volume = {475}, number = {2229}, pages = {20190175}, pmid = {31611714}, issn = {1364-5021}, abstract = {In the presence of glycoproteins, bacterial and yeast biofilms are hypothesized to expand by sliding motility. This involves a sheet of cells spreading as a unit, facilitated by cell proliferation and weak adhesion to the substratum. In this paper, we derive an extensional flow model for biofilm expansion by sliding motility to test this hypothesis. We model the biofilm as a two-phase (living cells and an extracellular matrix) viscous fluid mixture, and model nutrient depletion and uptake from the substratum. Applying the thin-film approximation simplifies the model, and reduces it to one-dimensional axisymmetric form. Comparison with Saccharomyces cerevisiae mat formation experiments reveals good agreement between experimental expansion speed and numerical solutions to the model with O (1) parameters estimated from experiments. This confirms that sliding motility is a possible mechanism for yeast biofilm expansion. Having established the biological relevance of the model, we then demonstrate how the model parameters affect expansion speed, enabling us to predict biofilm expansion for different experimental conditions. Finally, we show that our model can explain the ridge formation observed in some biofilms. This is especially true if surface tension is low, as hypothesized for sliding motility.}, } @article {pmid31610517, year = {2019}, author = {Beni, AA and Esmaeili, A}, title = {Design and optimization of a new reactor based on biofilm-ceramic for industrial wastewater treatment.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {255}, number = {Pt 2}, pages = {113298}, doi = {10.1016/j.envpol.2019.113298}, pmid = {31610517}, issn = {1873-6424}, mesh = {Adsorption ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Ceramics/*chemistry ; Hydrogen-Ion Concentration ; Kinetics ; Metals, Heavy/analysis ; Surface Properties ; Wastewater/*chemistry ; Water Pollutants, Chemical/*analysis ; Water Purification/*methods ; }, abstract = {A biofilm reactor was designed with flat ceramic substrates to remove Co(II), Ni(II) and Zn(II) from industrial wastewater. The ceramics were made of clay and nano-rubber with high mechanical resistance. The surface of the ceramic substrate was modified with neutral fiber and nano-hydroxyapatite. A uniform and stable biofilm mass of 320 g with 2 mm of thickness was produced on the modified ceramic after 3 d. The micro-organisms were identified in the biofilm by polymerase chain reaction (PCR) method. Functional groups of biofilms were identified with a Fourier transform infrared spectrometer (FT-IR). Experiments were designed by central composite design (CCD) using the responsive surface method (RSM). The biosorption process was optimized at pH = 5.8, temperature = 22 °C, feed flux of heavy metal wastewater = 225 ml, substrate flow = 30 ml, and retention time = 7.825 h. The kinetic data was analyzed by pseudo first-order and pseudo second-order kinetic models. Isotherm models and thermodynamic parameters were applied to describe the biosorption equilibrium data of the metal ions on the biofilm-ceramic. The maximum biosorption efficiency and capacity of heavy metal ions were about 72% and 57.21 mg, respectively.}, } @article {pmid31608256, year = {2019}, author = {Jwa, SK}, title = {Efficacy of Moringa oleifera Leaf Extracts against Cariogenic Biofilm.}, journal = {Preventive nutrition and food science}, volume = {24}, number = {3}, pages = {308-312}, pmid = {31608256}, issn = {2287-1098}, abstract = {Moringa oleifera leaves are beneficial for human health. Dental caries is closely related with cariogenic biofilm, which is an oral biofilm containing a high proportion of Streptococcus mutans. The purpose of this study was to investigate the antimicrobial effects of the M. oleifera leaf extracts on S. mutans and formation of cariogenic biofilm. Extract from M. oleifera leaves was derived using distilled water (DW) and ethyl alcohol (EtOH). S. mutans susceptibility assays were performed for each extract. Cariogenic biofilm was formed with or without DW and EtOH extract, and cariogenic biofilm was treated with both extracts. The biofilm was observed by confocal laser microscopy, and the bacteria in the biofilm were counted. Both extracts showed antimicrobial activity against S. mutans and inhibited formation of cariogenic biofilm. The EtOH extracts exhibited anti-biofilm activity. M. oleifera leaves may be potential candidates to prevent dental caries.}, } @article {pmid31608016, year = {2019}, author = {Catão, ECP and Pollet, T and Misson, B and Garnier, C and Ghiglione, JF and Barry-Martinet, R and Maintenay, M and Bressy, C and Briand, JF}, title = {Shear Stress as a Major Driver of Marine Biofilm Communities in the NW Mediterranean Sea.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1768}, pmid = {31608016}, issn = {1664-302X}, abstract = {While marine biofilms depend on environmental conditions and substrate, little is known about the influence of hydrodynamic forces. We tested different immersion modes (dynamic, cyclic and static) in Toulon Bay (north-western Mediterranean Sea; NWMS). The static mode was also compared between Toulon and Banyuls Bays. In addition, different artificial surfaces designed to hamper cell attachment (self-polishing coating: SPC; and fouling-release coating: FRC) were compared to inert plastic. Prokaryotic community composition was affected by immersion mode, surface characteristics and site. Rhodobacteriaceae and Flavobacteriaceae dominated the biofilm community structure, with distinct genera according to surface type or immersion mode. Cell density increased with time, greatly limited by hydrodynamic forces, and supposed to delay biofilm maturation. After 1 year, a significant impact of shear stress on the taxonomic structure of the prokaryotic community developed on each surface type was observed. When surfaces contained no biocides, roughness and wettability shaped prokaryotic community structure, which was not enhanced by shear stress. Conversely, the biocidal effect of SPC surfaces, already major in static immersion mode, was amplified by the 15 knots speed. The biofilm community on SPC was 60% dissimilar to the biofilm on the other surfaces and was distinctly colonized by Sphingomonadaceae ((Alter)Erythrobacter). At Banyuls, prokaryotic community structures were more similar between the four surfaces tested than at Toulon, due possibly to a masking effect of environmental constraints, especially hydrodynamic, which was greater than in Toulon. Finally, predicted functions such as cell adhesion confirmed some of the hypotheses drawn regarding biofilm formation over the artificial surfaces tested here.}, } @article {pmid31607570, year = {2020}, author = {Liao, CH and Chen, CS and Chen, YC and Jiang, NE and Farn, CJ and Shen, YS and Hsu, ML and Chang, CH}, title = {Vancomycin-loaded oxidized hyaluronic acid and adipic acid dihydrazide hydrogel: Bio-compatibility, drug release, antimicrobial activity, and biofilm model.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {53}, number = {4}, pages = {525-531}, doi = {10.1016/j.jmii.2019.08.008}, pmid = {31607570}, issn = {1995-9133}, mesh = {Adipates/chemistry ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Humans ; Hyaluronic Acid/chemistry ; Hydrogels/chemistry ; Mesenchymal Stem Cells/drug effects/microbiology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/drug therapy/microbiology ; Vancomycin/chemistry/*pharmacology ; }, abstract = {BACKGROUND: Prosthesis infection is a difficult-to-treat situation. Hydrogel is a novel biomaterial, which can be applied by simply spraying or by coating on implants before surgery and can be easily mixed with antibiotics.

METHODS: In order to evaluate the potential use of antibiotic-loaded hydrogel, we incorporated vancomycin into oxidized hyaluronic acid (HA) and adipic acid dihydrazide and evaluated the drug release and antimicrobial activity against methicillin-resistant Staphylococcus aureus (ATCC 29213).

RESULTS: The average release percentage of vancomycin on day 3 was about 86%. The antibiotic-loaded gel was biocompatible with mesenchymal stem cell, MC3T3, and L929 cell lines. The in vitro inhibition zones of vancomycin-loaded hydrogel [500X minimal inhibition concentration (MIC), 50X MIC, 10X MIC, and blank hydrogel] were 21, 13, 9, and 5 mm, respectively. In the Ti6Al4V implant biofilm model, 0.01-1% vancomycin-loaded gel exhibited significant anti-biofilm activity, measured by the MTT assay.

CONCLUSIONS: Vancomycin could be loaded onto oxidized HA and adipic acid dihydrazide, which exhibited excellent drug release and in vitro antimicrobial activity with minimal cell toxicity.}, } @article {pmid31605761, year = {2020}, author = {Parai, D and Banerjee, M and Dey, P and Mukherjee, SK}, title = {Reserpine attenuates biofilm formation and virulence of Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {138}, number = {}, pages = {103790}, doi = {10.1016/j.micpath.2019.103790}, pmid = {31605761}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/chemistry/metabolism ; Biofilms/*drug effects ; Chemical Phenomena ; Dose-Response Relationship, Drug ; Drug Synergism ; Hemolysis ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Models, Molecular ; Protein Binding ; Reserpine/chemistry/*pharmacology ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; Structure-Activity Relationship ; Virulence/*drug effects ; }, abstract = {This study investigated the effects of reserpine, the main bioactive compound of Rauwolfia serpentina, on biofilm formation and biofilm-associated virulence factors production in a Gram-positive pathogen, Staphylococcus aureus. Crystal violet assay, MTT assay, Congo red binding, CLSM studies were performed to assess the antibiofilm activity. Molecular docking was performed to explain the possible mode of action, catheter model was used to evaluate its application potential and the combinatorial study was performed in search of an improved therapeutic formulation. Reserpine affected biofilm formation, EPS production, biofilm cell viability and virulence factor production. It could eradicate 72.7% biofilm at ½ × MIC dose and could also stop the metabolic activity of 50.6% bacterial cells in a biofilm. Staphylococcus aureus biofilm- and virulence-regulatory proteins like AgrA, AtlE, Bap, IcaA, SarA and SasG were found to interact with reserpine which might lead to the attenuation of its pathogenicity. Reserpine along with other commercial antibiotics could generate a hightened antibiofilm response, and also eradicated a good percentage of bacterial biofilm from a urinary catheter model. These findings suggested reserpine as a good alternative entity to generate new improved therapeutic formulations.}, } @article {pmid31605708, year = {2019}, author = {Dai, L and Wu, TQ and Xiong, YS and Ni, HB and Ding, Y and Zhang, WC and Chu, SP and Ju, SQ and Yu, J}, title = {Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa.}, journal = {Life sciences}, volume = {237}, number = {}, pages = {116947}, doi = {10.1016/j.lfs.2019.116947}, pmid = {31605708}, issn = {1879-0631}, mesh = {Anti-Inflammatory Agents, Non-Steroidal/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/drug effects/*growth & development ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Ibuprofen/*pharmacology ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/*genetics/growth & development ; Quorum Sensing/*drug effects ; Virulence Factors/*genetics ; }, abstract = {AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems.

MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking.

KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores.

SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.}, } @article {pmid31603038, year = {2019}, author = {Mugge, RL and Lee, JS and Brown, TT and Hamdan, LJ}, title = {Marine biofilm bacterial community response and carbon steel loss following Deepwater Horizon spill contaminant exposure.}, journal = {Biofouling}, volume = {35}, number = {8}, pages = {870-882}, doi = {10.1080/08927014.2019.1673377}, pmid = {31603038}, issn = {1029-2454}, mesh = {Biodiversity ; Biofilms/*drug effects/growth & development ; Carbon/chemistry ; Corrosion ; Manufactured Materials/*microbiology ; Microbiota/*drug effects ; Petroleum/analysis/toxicity ; Petroleum Pollution/*adverse effects/analysis ; Proteobacteria/classification/*drug effects/isolation & purification ; RNA, Ribosomal, 16S/genetics ; *Steel/chemistry ; Water Pollutants, Chemical/analysis/toxicity ; }, abstract = {Steel marine structures provide foci of biodiversity when they develop into artificial reefs. Development begins with deposition of a biofilm. The effects of contaminants from oil spills on biofilm microbiomes, microbially-induced corrosion (MIC) and metal loss may impact preservation of marine metal structures. A microcosm experiment exposed biofilms on carbon steel disks (CSDs) to crude oil, dispersant, and dispersed oil to address their impacts on bacterial composition and metal loss and pitting. Biofilm diversity increased over time in all exposures. Community composition in dispersant and dispersed oil treatments deviated from the controls for the duration of a 12-week experiment. As biofilms matured, Pseudomonadaceae increased while Rhodobacteraceae decreased in abundance in dispersed oil treatments compared to the controls and dispersant treatments. Greatest mass loss and deepest pitting on CSDs were observed in dispersed oil treatments, suggesting impacts manifest as a consequence of increased MIC potential on carbon steel.}, } @article {pmid31602310, year = {2019}, author = {Rupel, K and Zupin, L and Ottaviani, G and Bertani, I and Martinelli, V and Porrelli, D and Vodret, S and Vuerich, R and Passos da Silva, D and Bussani, R and Crovella, S and Parsek, M and Venturi, V and Di Lenarda, R and Biasotto, M and Zacchigna, S}, title = {Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {29}, pmid = {31602310}, issn = {2055-5008}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development/*radiation effects ; Cell Line ; Culture Media ; Disease Models, Animal ; Humans ; *Lasers ; *Light ; Mice, Inbred C57BL ; Models, Biological ; *Oxidative Stress ; Pseudomonas Infections/therapy ; Pseudomonas aeruginosa/*growth & development/*radiation effects ; Radiotherapy/methods ; Treatment Outcome ; Wound Infection/therapy ; }, abstract = {Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.}, } @article {pmid31600988, year = {2019}, author = {Bardhan, T and Chakraborty, M and Bhattacharjee, B}, title = {Bactericidal Activity of Lactic Acid against Clinical, Carbapenem-Hydrolyzing, Multi-Drug-Resistant Klebsiella pneumoniae Planktonic and Biofilm-Forming Cells.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31600988}, issn = {2079-6382}, support = {Ramanujan Fellowship; SB/S2/RJN-013/2014//Science and Engineering Research Board/ ; }, abstract = {: Carbapenem resistant Klebsiella pneumoniae has been highlighted to be a critical pathogen by the World Health Organization. The objectives of this study were to assess the efficacy of lactic acid (LA) against planktonic cells and biofilms formed by carbapenem-hydrolyzing K. pneumoniae isolates obtained from the nares of preterm neonates. Time-kill assays with graded percentages of (v/v) LA in water were initially carried out against planktonic cells of a meropenem (MRP)-resistant K. pneumoniae isolate, JNM11.C4. The efficacy parameters such as optimal incubation time and minimum inhibitory concentration were determined by comparing colony-forming unit counts (log(10)CFU). Scanning electron microscopy was used to visualize cell damage. Likewise, JNM11.C4 biofilms were treated with graded series of (v/v) LA. Six carbapenem-hydrolyzing isolates were next used to validate the results. A reduction of 3.6 ± 0.6 log(10) CFU/mL in JNM11.C4 planktonic cells and >3 ± 0.03log(10) CFU/mL in biofilm-forming cells were observed using 0.225% and 2% LA, respectively, after three hours. Similar decreases in viable cell-counts were observed both in the case of planktonic (˃3.6 ± 0.3log(10) CFU/mL) and biofilm-forming cells (3.8 ± 0.3log(10) CFU/mL) across all the six clinical isolates. These results indicate that LA is an effective antimicrobial against planktonic carbapenem-hydrolyzing K. pneumoniae cells and biofilms.}, } @article {pmid31599377, year = {2019}, author = {Bakraoui, M and Hazzi, M and Karouach, F and Ouhammou, B and El Bari, H}, title = {Experimental biogas production from recycled pulp and paper wastewater by biofilm technology.}, journal = {Biotechnology letters}, volume = {41}, number = {11}, pages = {1299-1307}, doi = {10.1007/s10529-019-02735-w}, pmid = {31599377}, issn = {1573-6776}, support = {413223920433//University Ibn Tofail/ ; }, mesh = {Anaerobiosis/*physiology ; *Biofilms ; *Biofuels ; *Bioreactors ; Biotechnology ; Equipment Design ; Industrial Waste ; Oxygen/analysis/metabolism ; Paper ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater ; }, abstract = {OBJECTIVE: The main objective of this study is the evaluation of RPPW anaerobic digestion feasibility at laboratory scale under Mesophilic condition. The experiment is conducted using a two-stage biofilm digester of 5 L capacity with mobile support material.

RESULTS: Anaerobic treatment of wastewater from recycled pulp and paper industry in Morocco was tested using a laboratory-scale anaerobic biofilm digester that operated under mesophilic conditions over a 70-day. Chemical oxygen demand (COD) efficiency, volatile and total solid (VS, TS) elimination of the substrate during the process were: 78%, 52% and 48% respectively. The system was stable throughout its operating cycle with an optimum pH (7.24), alkalinity (1750 mg CaCO3/L) and a volatile fatty acid value (760 mg/L). The experimental daily biogas production measured reaches a value of 5 L/day with a composition of 71% methane, 27.6% carbon dioxide, 0.2 oxygen and 7713 ppm of the H2S. The study results show that the anaerobic biofilm reactor is a suitable technique for recycled pulp and paper wastewater (RPPW) treatment. The reactor shows high performances in terms of process stability, removal efficiency (> 70%) and biogas production.

CONCLUSION: Anaerobic digestion is an efficient waste treatment technology that uses natural anaerobic decomposition to reduce the volume of waste while producing biogas. However, research is needed to strengthen microbial metabolism, biochemistry and the functioning of the rector to improve biogas production. The RPPW AD experiment with biofilm digester technology was stable throughout the operation period. The digester knows an overloaded in the last phase of the experiment which leads to an inhibition of biogas production.}, } @article {pmid31599128, year = {2019}, author = {Turner, ME and Huynh, K and Carney, OV and Gross, D and Carroll, RK and Ahn, SJ and Rice, KC}, title = {Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.}, journal = {MicrobiologyOpen}, volume = {8}, number = {12}, pages = {e934}, pmid = {31599128}, issn = {2045-8827}, support = {R01 DE025237/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; *DNA Transposable Elements ; Dental Caries/etiology ; Gene Expression Regulation, Bacterial ; *Genomic Instability ; Genomic Islands ; High-Throughput Nucleotide Sequencing ; Humans ; *Mutation ; Oxidative Stress ; Phenotype ; Polymorphism, Single Nucleotide ; Streptococcus mutans/*genetics/*growth & development ; }, abstract = {Streptococcus mutans is a key pathogenic bacterium in the oral cavity and a primary contributor to dental caries. The S. mutans Cid/Lrg system likely contributes to tolerating stresses encountered in this environment as cid and/or lrg mutants exhibit altered oxidative stress sensitivity, genetic competence, and biofilm phenotypes. It was recently noted that the cidB mutant had two stable colony morphologies: a "rough" phenotype (similar to wild type) and a "smooth" phenotype. In our previously published work, the cidB rough mutant exhibited increased sensitivity to oxidative stress, and RNAseq identified widespread transcriptomic changes in central carbon metabolism and oxidative stress response genes. In this current report, we conducted Illumina-based genome resequencing of wild type, cidB rough, and cidB smooth mutants and compared their resistance to oxidative and acid stress, biofilm formation, and competence phenotypes. Both cidB mutants exhibited comparable aerobic growth inhibition on agar plates, during planktonic growth, and in the presence of 1 mM hydrogen peroxide. The cidB smooth mutant displayed a significant competence defect in BHI, which was rescuable by synthetic CSP. Both cidB mutants also displayed reduced XIP-mediated competence, although this reduction was more pronounced in the cidB smooth mutant. Anaerobic biofilms of the cidB smooth mutant displayed increased propidium iodide staining, but corresponding biofilm CFU data suggest this phenotype is due to cell damage and not increased cell death. The cidB rough anaerobic biofilms showed altered structure relative to wild type (reduced biomass and average thickness) which correlated with decreased CFU counts. Sequencing data revealed that the cidB smooth mutant has a unique "loss of read coverage" of ~78 kb of DNA, corresponding to the genomic island TnSMU2 and genes flanking its 3' end. It is therefore likely that the unique biofilm and competence phenotypes of the cidB smooth mutant are related to its genomic changes in this region.}, } @article {pmid31594958, year = {2019}, author = {Liu, W and Tian, XQ and Wei, JW and Ding, LL and Qian, W and Liu, Z and Wang, FF}, title = {Author Correction: BsmR degrades c-di-GMP to modulate biofilm formation of nosocomial pathogen Stenotrophomonas maltophilia.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {14778}, doi = {10.1038/s41598-019-43380-7}, pmid = {31594958}, issn = {2045-2322}, abstract = {A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.}, } @article {pmid31593452, year = {2019}, author = {Chen, H and Luo, J and Liu, S and Yuan, Z and Guo, J}, title = {Microbial Methane Conversion to Short-Chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors.}, journal = {Environmental science & technology}, volume = {53}, number = {21}, pages = {12846-12855}, doi = {10.1021/acs.est.8b06767}, pmid = {31593452}, issn = {1520-5851}, mesh = {Biofilms ; Bioreactors ; *Electrons ; Fatty Acids, Volatile ; Membranes ; *Methane ; }, abstract = {Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate, and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs) and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L[-1] d[-1], or 3.4 to 114.6 mg acetate d[-1] m[-2] of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100%, suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d[-1] m[-2] was found to be the most favorable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.}, } @article {pmid31590609, year = {2020}, author = {Diaz, PI and Valm, AM}, title = {Microbial Interactions in Oral Communities Mediate Emergent Biofilm Properties.}, journal = {Journal of dental research}, volume = {99}, number = {1}, pages = {18-25}, pmid = {31590609}, issn = {1544-0591}, support = {R03 DE028042/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacteria ; *Biofilms ; *Microbial Interactions ; *Microbiota ; Virulence ; }, abstract = {Oral microbial communities are extraordinarily complex in taxonomic composition and comprise interdependent biological systems. The bacteria, archaea, fungi, and viruses that thrive within these communities engage in extensive cell-cell interactions, which are both beneficial and antagonistic. Direct physical interactions among individual cells mediate large-scale architectural biofilm arrangements and provide spatial proximity for chemical communication and metabolic cooperation. In this review, we summarize recent work in identifying specific molecular components that mediate cell-cell interactions and describe metabolic interactions, such as cross-feeding and exchange of electron acceptors and small molecules, that modify the growth and virulence of individual species. We argue, however, that although pairwise interaction models have provided useful information, complex community-like systems are needed to study the properties of oral communities. The networks of multiple synergistic and antagonistic interactions within oral biofilms give rise to the emergent properties of persistence, stability, and long-range spatial structure, with these properties mediating the dysbiotic transitions from health to oral diseases. A better understanding of the fundamental properties of interspecies networks will lead to the development of effective strategies to manipulate oral communities.}, } @article {pmid31589910, year = {2020}, author = {Miryala, S and Makala, H and Yadavali, SP and Venkatasubramanian, U and Subbaiah, N and Srinandan, CS}, title = {Disperse red 15 (DR15) impedes biofilm formation of uropathogenic Escherichia coli.}, journal = {Microbial pathogenesis}, volume = {138}, number = {}, pages = {103772}, doi = {10.1016/j.micpath.2019.103772}, pmid = {31589910}, issn = {1096-1208}, mesh = {Adhesins, Escherichia coli ; Anthraquinones/chemistry/*pharmacology ; Binding Sites ; Biofilms/*drug effects ; Catheter-Related Infections/etiology ; Computer Simulation ; Drug Evaluation, Preclinical ; Escherichia coli Infections/microbiology ; Humans ; Ligands ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Molecular Structure ; Protein Binding ; Urinary Catheters/adverse effects ; Urinary Tract Infections/etiology ; Uropathogenic Escherichia coli/*drug effects/*growth & development ; }, abstract = {Catheter associated urinary tract infection (CAUTI) is a highly prevalent hospital-acquired infection that is predominantly caused by uropathogenic Escherichia coli (UPEC). It adheres on catheter surface using type I pili as the initial step of pathogenesis that progresses to form biofilm. In this study, potential inhibitors against FimH adhesin of type I pili were screened computationally that yielded ten compounds. These were further validated in vitro against adhesion and biofilm formation. The compounds, 1-Amino-4-hydroxyanthraquinone (Disperse Red 15 or DR15) and 4-(4'-chloro-4-biphenylylsulfonylamino) benzoic acid (CB1) impaired adhesion and biofilm formation without inhibiting the planktonic growth. Also, both compounds inhibited cell assemblages like autoaggregation and swarming motility by unknown mechanisms. DR15 was further derivatised into N-(4-hydroxy-9,10-dioxo-9,10-dihydroanthracen-1-yl) undec-10-enamide that self-assembled with linseed oil, which was used as the coating material on urinary Foley catheters. The thin-film coating on the catheter did not leach when incubated in artificial urine and effectively restricted biofilm formation of UPEC. Altogether, the thin-film coating of urinary catheter with DR15 inhibited biofilm formation of UPEC and this application could potentially help to reduce CAUTI incidents in healthcare facilities.}, } @article {pmid31589311, year = {2019}, author = {Silva, MOD and Pernthaler, J}, title = {Priming of microcystin degradation in carbon-amended membrane biofilm communities is promoted by oxygen-limited conditions.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {11}, pages = {}, pmid = {31589311}, issn = {1574-6941}, mesh = {Bacterial Toxins/*metabolism ; *Biofilms ; Biomass ; Carbon/metabolism ; Diatoms/metabolism ; Microcystins/*metabolism ; Microcystis/metabolism ; Oxygen/*metabolism ; }, abstract = {Microbial biofilms are an important element of gravity-driven membrane (GDM) filtration systems for decentralized drinking water production. Mature biofilms fed with biomass from the toxic cyanobacterium Microcystis aeruginosa efficiently remove the cyanotoxin microcystin (MC). MC degradation can be 'primed' by prior addition of biomass from a non-toxic M. aeruginosa strain. Increased proportions of bacteria with an anaerobic metabolism in M. aeruginosa-fed biofilms suggest that this 'priming' could be due to higher productivity and the resulting changes in habitat conditions. We, therefore, investigated GDM systems amended with the biomass of toxic (WT) or non-toxic (MUT) M. aeruginosa strains, of diatoms (DT), or with starch solution (ST). After 25 days, these treatments were changed to receiving toxic cyanobacterial biomass. MC degradation established significantly more rapidly in MUT and ST than in DT. Oxygen measurements suggested that this was due to oxygen-limited conditions in MUT and ST already prevailing before addition of MC-containing biomass. Moreover, the microbial communities in the initial ST biofilms featured high proportions of facultative anaerobic taxa, whereas aerobes dominated in DT biofilms. Thus, the 'priming' of MC degradation in mature GDM biofilms seems to be related to the prior establishment of oxygen-limited conditions mediated by higher productivity.}, } @article {pmid31589240, year = {2019}, author = {Favre, L and Ortalo-Magné, A and Kerloch, L and Pichereaux, C and Misson, B and Briand, JF and Garnier, C and Culioli, G}, title = {Metabolomic and proteomic changes induced by growth inhibitory concentrations of copper in the biofilm-forming marine bacterium Pseudoalteromonas lipolytica.}, journal = {Metallomics : integrated biometal science}, volume = {11}, number = {11}, pages = {1887-1899}, doi = {10.1039/c9mt00184k}, pmid = {31589240}, issn = {1756-591X}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects/*growth & development ; Copper/*toxicity ; Discriminant Analysis ; Least-Squares Analysis ; Metabolome/drug effects ; *Metabolomics ; Multivariate Analysis ; Plankton/cytology/drug effects ; *Proteomics ; Pseudoalteromonas/drug effects/*growth & development ; Seawater/*microbiology ; }, abstract = {Copper is an essential element for living cells but this metal is present in some marine environments at such high concentrations that it can be toxic for numerous organisms. In polluted areas, marine organisms may develop specific adaptive responses to prevent cell damage. To investigate the influence of copper on the metabolism of a single organism, a dual approach combining metabolomics and proteomics was undertaken on the biofilm-forming bacterial strain Pseudoalteromonas lipolytica TC8. In order to highlight differential adaptation according to the phenotype, the response of P. lipolytica TC8 to copper stress was studied in planktonic and biofilm culture modes under growth inhibitory copper concentrations. As expected, copper exposure led to the induction of defense and detoxification mechanisms. Specific metabolite and protein profiles were thus observed in each condition (planktonic vs. biofilm and control vs. copper-treated cultures). Copper exposure seems to induce drastic changes in the lipid composition of the bacterial cell membrane and to modulate the abundance of proteins functionally known to be involved in copper cell homeostasis in both planktonic and biofilm culture modes. Much more proteins differentially expressed after copper treatment were observed in biofilms than in planktonic cells, which could indicate a more heterogeneous response of biofilm cells to this metallic stress.}, } @article {pmid31586764, year = {2019}, author = {Liu, X and Zhuo, S and Jing, X and Yuan, Y and Rensing, C and Zhou, S}, title = {Flagella act as Geobacter biofilm scaffolds to stabilize biofilm and facilitate extracellular electron transfer.}, journal = {Biosensors & bioelectronics}, volume = {146}, number = {}, pages = {111748}, doi = {10.1016/j.bios.2019.111748}, pmid = {31586764}, issn = {1873-4235}, mesh = {Biofilms/*growth & development ; Cytochromes/genetics/metabolism ; Electric Conductivity ; Electron Transport ; Electrons ; Flagella/genetics/*physiology ; Geobacter/enzymology/genetics/*physiology ; Mutation ; }, abstract = {Flagella are widely expressed in electroactive biofilms; however, their actual role is unknown. To understand the role of flagella, two Geobacter sulfurreducens strains (KN400 and PCA, with and without flagella, respectively) were selected. We restored flagellum expression in trans in strain PCA and prevented flagellum expression in strain KN400. Electrochemical results showed that flagellum restoration in strain PCA promoted current generation, while flagellum deletion in strain KN400 impaired current production. However, the expression of conductive pili and outer surface c-type cytochromes was not affected. Further microscopic analyses demonstrated that flagella promoted the formation of thicker biofilms and served as biofilm matrix scaffolds to accommodate more extracellular cytochromes with an orderly arrangement, which increased the electron diffusion rate within the biofilm. Our findings reveal an unprecedented structural role for flagella in stabilizing electroactive biofilms and highlight the importance of cytochromes in electron transfer across biofilms, which will deepen our understanding of biofilm conductivity.}, } @article {pmid31586475, year = {2019}, author = {Shi, N and Gao, Y and Yin, D and Song, Y and Kang, J and Li, X and Zhang, Z and Feng, X and Duan, J}, title = {The effect of the sub-minimal inhibitory concentration and the concentrations within resistant mutation window of ciprofloxacin on MIC, swimming motility and biofilm formation of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {137}, number = {}, pages = {103765}, doi = {10.1016/j.micpath.2019.103765}, pmid = {31586475}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Drug Resistance, Bacterial/drug effects ; Microbial Sensitivity Tests ; Mutation ; Pseudomonas aeruginosa/*drug effects/genetics/*physiology ; }, abstract = {OBJECTIVE: To explore the effect of sub-minimal inhibitory concentration (sub-MIC) and concentrations within resistant mutation window (MSW) of ciprofloxacin (CIP) on minimal inhibitory concentration (MIC), swimming motility and biofilm formation of Pseudomonas aeruginosa, and also to investigate the correlation between swimming motility and genes expression of lasI, lasR, rhlI, rhlR and pqsR.

METHODS: The collected strains were incubated under four different concentrations for 5 days. The MIC and mutant prevention concentration (MPC) were measured by the agar dilution method. The diameter of turbid cycle was used to signify the swimming motility. The biofilm formation was measured by the crystal violet stain method. The genes expression of lasI, lasR, rhlI, rhlR and pqsR were measured by RT-PCR.

RESULTS: A total of 11 P. aeruginosa which sensitive to CIP were collected. The incubation within concentrations of MSW made MICs to CIP increased more obviously than under sub-MIC (P < 0.05). The swimming motility showed a trend of being inhibited first and then promoted over time under sub-MIC (P < 0.05), whereas, it was promoted under concentrations within MSW. The biofilm formation was significantly promoted under the concentration of 4×MIC (P < 0.05). Under sub-MIC, the genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility (P < 0.05, r = 0.788 and P < 0.05, r = 0.652, respectively).

CONCLUSIONS: Under the concentration of sub-MIC (0.5×MIC) and the concentrations within MSW (1×MIC, 2×MIC and 4×MIC), the effect of CIP on MICs, swimming motility and biofilm formation of P.aeruginosa was quite different. The genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility.}, } @article {pmid31585061, year = {2020}, author = {Thompson, AF and English, EL and Nock, AM and Willsey, GG and Eckstrom, K and Cairns, B and Bavelock, M and Tighe, SW and Foote, A and Shulman, H and Pericleous, A and Gupta, S and Kadouri, DE and Wargo, MJ}, title = {Characterizing species interactions that contribute to biofilm formation in a multispecies model of a potable water bacterial community.}, journal = {Microbiology (Reading, England)}, volume = {166}, number = {1}, pages = {34-43}, pmid = {31585061}, issn = {1465-2080}, support = {P20 GM103449/GM/NIGMS NIH HHS/United States ; P30 GM118228/GM/NIGMS NIH HHS/United States ; T32 HL076122/HL/NHLBI NIH HHS/United States ; }, mesh = {Bacteria/classification/growth & development/isolation & purification/virology ; Bacteriophages/physiology ; Biofilms/*growth & development ; Drinking Water/*microbiology ; Microbial Interactions/*physiology ; *Microbiota ; Spacecraft ; Water Microbiology ; }, abstract = {Microbial biofilms are ubiquitous in drinking water systems, yet our understanding of drinking water biofilms lags behind our understanding of those in other environments. Here, a six-member model bacterial community was used to identify the interactions and individual contributions of each species to community biofilm formation. These bacteria were isolated from the International Space Station potable water system and include Cupriavidus metallidurans, Chryseobacterium gleum, Ralstonia insidiosa, Ralstonia pickettii, Methylorubrum (Methylobacterium) populi and Sphingomonas paucimobilis, but all six species are common members of terrestrial potable water systems. Using reconstituted assemblages, from pairs to all 6 members, community biofilm formation was observed to be robust to the absence of any single species and only removal of the C. gleum/S. paucimobilis pair, out of all 15 possible 2-species subtractions, led to loss of community biofilm formation. In conjunction with these findings, dual-species biofilm formation assays supported the view that the contribution of C. gleum to community biofilm formation was dependent on synergistic biofilm formation with either R. insidiosa or C. metallidurans. These data support a model of multiple, partially redundant species interactions to generate robustness in biofilm formation. A bacteriophage and multiple predatory bacteria were used to test the resilience of the community to the removal of individual members in situ, but the combination of precise and substantial depletion of a single target species was not achievable. We propose that this assemblage can be used as a tractable model to understand the molecular bases of the interactions described here and to decipher other functions of drinking water biofilms.}, } @article {pmid31585041, year = {2019}, author = {Xi, Y and Wang, Y and Gao, J and Xiao, Y and Du, J}, title = {Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis.}, journal = {ACS nano}, volume = {13}, number = {12}, pages = {13645-13657}, doi = {10.1021/acsnano.9b03237}, pmid = {31585041}, issn = {1936-086X}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Drug Carriers/*chemistry ; *Drug Delivery Systems ; Escherichia coli/drug effects ; Inflammation/pathology ; Microbial Sensitivity Tests ; Periodontitis/*drug therapy/*microbiology ; Plankton/drug effects ; Polymers/chemical synthesis/chemistry ; Rats ; Staphylococcus aureus/drug effects ; }, abstract = {Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low-dose antibiotic therapy is a complicated challenge for eradicating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances in biofilms ("stealthy" coronas), whereas P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli or Staphylococcus aureus biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this "stealthy" and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.}, } @article {pmid31584765, year = {2019}, author = {García, A and Martínez, C and Juárez, RI and Téllez, R and Paredes, MA and Herrera, MDR and Giono, S}, title = {Methicillin resistance and biofilm production in clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus in México.}, journal = {Biomedica : revista del Instituto Nacional de Salud}, volume = {39}, number = {3}, pages = {513-523}, pmid = {31584765}, issn = {2590-7379}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cefoxitin/pharmacology ; Coagulase ; DNA, Bacterial/isolation & purification ; Genes, Bacterial ; Humans ; *Methicillin Resistance/genetics ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics ; Mexico ; Microbial Sensitivity Tests/methods ; Oxacillin/pharmacology ; Penicillin-Binding Proteins/genetics ; Staphylococcal Infections/microbiology ; Staphylococcus/*drug effects/enzymology/genetics/*physiology ; Staphylococcus aureus/*drug effects/genetics/*physiology ; }, abstract = {Introduction: Infections associated with health care caused by S. aureus and coagulase-negative Staphylococci multi-resistant to antibiotics cause a high epidemiological impact due to their high morbidity and mortality. Biofilm formation, which has been associated with antimicrobial resistance, can also occur. Objectives: To determine methicillin resistance and to quantify the biofilm production to establish if there is a relationship in clinical isolates of S. aureus and coagulase-negative Staphylococci. Material and methods: A total of 11 strains of S. aureus and 12 of coagulase-negative Staphylococci were studied. Methicillin resistance was determined with cefoxitin discs and the Clinical Laboratory Standards Institute (CSLI), 2018 reference values. Biofilm production was quantified by the crystal violet method. The mecA and icaADBC genes were identified by PCR. A bivariate analysis was performed with chi-square (c2) and Cramér’s V statistical tests, using SPSS™, version 20.0 software. Results: Nine S. aureus strains were methicillin-resistant and two were sensitive. Eight coagulase-negative Staphylococci strains were resistant and four were sensitive. The mecA genotype was found in eight of the nine S. aureus resistant strains and six of eight resistant coagulase-negative Staphylococci. All strains formed biofilms. Ten strains of S. aureus and 11 of coagulase-negative Staphylococci presented the icaADCB genotype. No association was found between methicillin-resistance and biofilm formation. Conclusions: Cefoxitin is enough to define the resistance phenotype and is associated with the mecA genotype. All strains formed biofilms and were related to the presence of the icaADCB operon. Biofilm formation and methicillin resistance were independent features in both groups of strains.}, } @article {pmid31584713, year = {2019}, author = {Soares Dos Santos, DM and Braga, AS and Rizk, M and Wiegand, A and Magalhães, AC}, title = {Comparison between micro-computed tomography and transverse microradiography of sound dentine treated with fluorides and demineralized by microcosm biofilm.}, journal = {European journal of oral sciences}, volume = {127}, number = {6}, pages = {508-514}, doi = {10.1111/eos.12656}, pmid = {31584713}, issn = {1600-0722}, mesh = {Animals ; Biofilms/*growth & development ; Cariostatic Agents/*pharmacology ; Cattle ; Dental Caries/prevention & control ; *Dentin ; Fluorides ; Fluorides, Topical/*pharmacology ; Humans ; *Microradiography ; Sodium Fluoride/pharmacology ; *Tooth Demineralization ; *X-Ray Microtomography ; }, abstract = {The study aimed to apply micro-computed tomography (micro-CT) and transverse microradiography (TMR) to measure dentine demineralization and to test the preventive effect of titanium tetrafluoride (TiF4) under microcosm biofilm. Sound dentine specimens from bovine root were treated for 6 h with: (i) 4.0% titanium tetrafluoride (TiF4) varnish [pH 1.0, 2.45% fluoride (F-); (ii) 5.42% sodium fluoride (NaF) varnish (pH 5.0, 2.45% F); (iii) 2% chlorhexidine (CHX) gel (pH 7.0); (iv) placebo varnish (pH 5.0); or (v) no agent (untreated). Dentine specimens were then exposed to human saliva mixed with McBain saliva for 8 h. Thereafter, McBain saliva containing 0.2% sucrose was applied daily, for 5 d, onto dentine specimens to stimulate formation of microcosm biofilm. Although a high correlation was found between the results of both methods regarding integrated mineral loss, the results of the methods did not show good agreement in Bland-Altman plots, with significant biases in calculations of lesion depth. Fluoride varnishes were able to reduce dentine demineralization (P < 0.05), while CHX failed to do so. Fluorides are still the best option to reduce dentine demineralization. Micro-CT may be used to measure dentine mineral loss, but not the lesion depth, for which TMR is superior.}, } @article {pmid31584030, year = {2019}, author = {Yadav, S and Sachdev, V and Malik, M and Chopra, R}, title = {Effect of three different compositions of topical fluoride varnishes with and without prior oral prophylaxis on Streptococcus mutans count in biofilm samples of children aged 2-8 years: A randomized controlled trial.}, journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry}, volume = {37}, number = {3}, pages = {286-291}, doi = {10.4103/JISPPD.JISPPD_62_19}, pmid = {31584030}, issn = {1998-3905}, mesh = {Biofilms ; Cariostatic Agents ; Child ; Child, Preschool ; *Dental Caries ; *Dental Plaque ; Fluorides ; Fluorides, Topical ; Humans ; Streptococcus mutans ; }, abstract = {BACKGROUND: Various strategies for controlling caries focus on disrupting the interaction between risk factors. Of these, fluoride varnish has been shown to reduce the colony-forming (CFU) units and water-insoluble extracellular polysaccharide amount. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol-containing fluoride varnishes have recently gained importance as caries-protective fluoride varnishes.

AIM: This study aims to assess and compare the reduction in Streptococcus mutans count in biofilm samples after topical application of three different fluoride varnishes and to evaluate the effect of oral prophylaxis prior to fluoride varnish application.

MATERIALS AND METHODS: Sixty healthy children with no active caries, in the age group of 2-8 years, were randomly divided into Group A = fluoride varnish containing CPP-ACP; Group B = fluoride varnish containing xylitol; and Group C = fluoride varnish with 0.9% difluorosilane; further, the groups were divided into two subgroups, namely A1, B1, and C1 with prior oral prophylaxis and A2, B2, and C2 without oral prophylaxis. Plaque samples were collected at baseline, 1[st] month, and 3[rd] month; cultured; and incubated, and CFU/ml was calculated.

RESULTS: Data were compiled, and CFU/ml was analyzed by independent t-test, paired t-test, and one-way ANOVA. There was no statistical difference between the fluoride groups. Furthermore, no statistically significant difference was seen between the subgroups.

CONCLUSION: Fluoride varnish containing CPP-ACP showed higher reduction in S. mutans count followed by xylitol-containing fluoride varnish and Fluor Protector[®]. There was no effect of prior oral prophylaxis on the efficacy of fluoride varnish.}, } @article {pmid31583791, year = {2019}, author = {Dundas, AA and Sanni, O and Dubern, JF and Dimitrakis, G and Hook, AL and Irvine, DJ and Williams, P and Alexander, MR}, title = {Validating a Predictive Structure-Property Relationship by Discovery of Novel Polymers which Reduce Bacterial Biofilm Formation.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {31}, number = {49}, pages = {e1903513}, pmid = {31583791}, issn = {1521-4095}, support = {//University of Nottingham/ ; EP/N006615/1//Engineering and Physical Sciences Research Council/ ; /WT_/Wellcome Trust/United Kingdom ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/drug effects ; Bacterial Infections/prevention & control ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects ; Biofouling/prevention & control ; Humans ; Polymers/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Synthetic materials are an everyday component of modern healthcare yet often fail routinely as a consequence of medical-device-centered infections. The incidence rate for catheter-associated urinary tract infections is between 3% and 7% for each day of use, which means that infection is inevitable when resident for sufficient time. The O'Neill Review on antimicrobial resistance estimates that, left unchecked, ten million people will die annually from drug-resistant infections by 2050. Development of biomaterials resistant to bacterial colonization can play an important role in reducing device-associated infections. However, rational design of new biomaterials is hindered by the lack of quantitative structure-activity relationships (QSARs). Here, the development of a predictive QSAR is reported for bacterial biofilm formation on a range of polymers, using calculated molecular descriptors of monomer units to discover and exemplify novel, biofilm-resistant (meth-)acrylate-based polymers. These predictions are validated successfully by the synthesis of new monomers which are polymerized to create coatings found to be resistant to biofilm formation by six different bacterial pathogens: Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus.}, } @article {pmid31583108, year = {2019}, author = {Guilhen, C and Miquel, S and Charbonnel, N and Joseph, L and Carrier, G and Forestier, C and Balestrino, D}, title = {Colonization and immune modulation properties of Klebsiella pneumoniae biofilm-dispersed cells.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {25}, pmid = {31583108}, issn = {2055-5008}, mesh = {Animals ; *Bacterial Adhesion ; Bacterial Load ; Biofilms/*growth & development ; Disease Models, Animal ; Immune Evasion ; Immunity, Innate ; Klebsiella Infections/immunology/*microbiology ; Klebsiella pneumoniae/*growth & development/*immunology ; Lung/microbiology ; Macrophages/immunology/microbiology ; Mice ; Microbial Viability ; Phagocytosis ; *Phenotype ; Pneumonia, Bacterial/immunology/*microbiology ; Time Factors ; }, abstract = {Biofilm-dispersal is a key determinant for further dissemination of biofilm-embedded bacteria. Recent evidence indicates that biofilm-dispersed bacteria have transcriptional features different from those of both biofilm and planktonic bacteria. In this study, the in vitro and in vivo phenotypic properties of Klebsiella pneumoniae cells spontaneously dispersed from biofilm were compared with those of planktonic and sessile cells. Biofilm-dispersed cells, whose growth rate was the same as that of exponential planktonic bacteria but significantly higher than those of sessile and stationary planktonic forms, colonized both abiotic and biotic surfaces more efficiently than their planktonic counterparts regardless of their initial adhesion capabilities. Microscopy studies suggested that dispersed bacteria initiate formation of microcolonies more rapidly than planktonic bacteria. In addition, dispersed cells have both a higher engulfment rate and better survival/multiplication inside macrophages than planktonic cells and sessile cells. In an in vivo murine pneumonia model, the bacterial load in mice lungs infected with biofilm-dispersed bacteria was similar at 6, 24 and 48 h after infection to that of mice lungs infected with planktonic or sessile bacteria. However, biofilm-dispersed and sessile bacteria trend to elicit innate immune response in lungs to a lesser extent than planktonic bacteria. Collectively, the findings from this study suggest that the greater ability of K. pneumoniae biofilm-dispersed cells to efficiently achieve surface colonization and to subvert the host immune response confers them substantial advantages in the first steps of the infection process over planktonic bacteria.}, } @article {pmid31581486, year = {2019}, author = {Aquino-Martins, VGQ and Melo, LFM and Silva, LMP and Targino de Lima, TR and Fernandes Queiroz, M and Viana, RLS and Zucolotto, SM and Andrade, VS and Rocha, HAO and Scortecci, KC}, title = {In Vitro Antioxidant, Anti-Biofilm, and Solar Protection Activities of Melocactus zehntneri (Britton & Rose) Pulp Extract.}, journal = {Antioxidants (Basel, Switzerland)}, volume = {8}, number = {10}, pages = {}, pmid = {31581486}, issn = {2076-3921}, support = {111//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; scholarship//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, abstract = {Cactaceae plants are important due to their nutritional and therapeutic values. This study aimed to identify the phytochemical profile and biological activities of six Melocactus zehntneri pulp extracts: hexane extract (HE), chloroform extract (CE), ethanol extract (EE), methanol extract (ME), final water extract (FWE), and water extract (WE). Sugar, phenolic compounds, and protein content of the extracts were determined. Then thin layer chromatography (TLC) was performed to detect the presence of terpenes (ursolic and oleanolic acids), saponins, sugars, and glycoproteins. These extracts were analyzed for antioxidant activity via in vitro assay. HE showed 75% ferric chelating activity. All extracts showed 80-100% superoxide and hydroxyl radical-scavenging activities, respectively. Further, all extracts at 25 µg/mL showed 60% activity against DPPH. Moreover, in the 3T3 cells lines, no cytotoxicity was observed; however, therapeutic activity against the effects of the H2O2 treatment was exhibited. Finally, the polar extracts (EE, ME, FWE, and WE), particularly WE, elicited activity against the biofilms of Staphylococcus epidermidis, and HE and CE expressed a capacity for solar protection.}, } @article {pmid31581038, year = {2019}, author = {Henning, N and Falås, P and Castronovo, S and Jewell, KS and Bester, K and Ternes, TA and Wick, A}, title = {Biological transformation of fexofenadine and sitagliptin by carrier-attached biomass and suspended sludge from a hybrid moving bed biofilm reactor.}, journal = {Water research}, volume = {167}, number = {}, pages = {115034}, doi = {10.1016/j.watres.2019.115034}, pmid = {31581038}, issn = {1879-2448}, mesh = {*Biofilms ; Biomass ; Bioreactors ; Chromatography, Liquid ; *Sewage ; Sitagliptin Phosphate ; Tandem Mass Spectrometry ; Terfenadine/analogs & derivatives ; }, abstract = {Laboratory-scale experiments were conducted to investigate the (bio)transformation of the antidiabetic sitagliptin (STG) and the antihistamine fexofenadine (FXF) during wastewater treatment. As inoculum either attached-growth on carriers or suspended sludge from a hybrid moving bed biofilm reactor (HMBBR) was used. Both target compounds were incubated in degradation experiments and quantified via LC-MS/MS for degradation kinetics. Furthermore transformation products (TPs) were analyzed via high resolution mass spectrometry (HRMS). Structural elucidation of the TPs was based on the high resolution molecular ion mass to propose a molecular formula and on MS[2] fragmentation to elucidate the chemical structure of the TPs. In total, 22 TPs (9 TPs for STG and 13 TPs for FXF) were detected in the experiments with STG and FXF. For all TPs, chemical structures could be proposed. STG was mainly transformed via amide hydrolysis and conjugation of the primary amine moiety. In contrast, FXF was predominantly transformed by oxidative reactions such as oxidation (dehydrogenation) and hydroxylation. Furthermore, FXF was removed significantly faster in contact with carriers compared to suspended sludge, whereas STG was degraded slightly faster in contact with suspended sludge. Moreover, the primary TP of FXF was also degraded faster in contact with carriers leading to higher proportions of secondary TPs. Thus, the microbial community of both carriers and suspended sludge catalyzed the same primary transformation reactions but the transformation kinetics of FXF and the formation/degradation of FXF TPs were considerably higher in contact with carrier-attached biomass. The primary degradation of both target compounds in pilot- and full-scale conventional activated sludge (CAS) and MBBR reactors reached 42 and 61% for FXF and STG, respectively. Up to three of the identified TPs of FXF and 8 TPs of STG were detected in the effluents of pilot- and full-scale CAS and MBBR.}, } @article {pmid31580958, year = {2019}, author = {Arteaga, V and Lamas, A and Regal, P and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM}, title = {Antimicrobial activity of apitoxin from Apis mellifera in Salmonella enterica strains isolated from poultry and its effects on motility, biofilm formation and gene expression.}, journal = {Microbial pathogenesis}, volume = {137}, number = {}, pages = {103771}, doi = {10.1016/j.micpath.2019.103771}, pmid = {31580958}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Bee Venoms/isolation & purification/*pharmacology ; Bees/*chemistry ; Biofilms/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Poultry ; Poultry Diseases/*microbiology ; Salmonella Infections, Animal/*microbiology ; Salmonella enterica/*drug effects/genetics/isolation & purification/physiology ; }, abstract = {Salmonella is a major global food-borne pathogen. One of the main concerns related to Salmonella and other food-borne pathogens is their capacity to acquire antimicrobial resistance and produce biofilms. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new antimicrobial substances is one of the main challenges in microbiological research. An additional challenge is the development of new methods and substances to inhibit and destruct biofilms. We determined the antimicrobial and antibiofilm activities of apitoxin in 16 Salmonella strains isolated from poultry. In addition, the effect of apitoxin on Salmonella motility and the expression of biofilm- and virulence-related genes was evaluated. The minimum inhibitory concentrations (MIC) of apitoxin ranged from 1,024-256 μg/mL, with 512 μg/mL being the most common. Sub-inhibitory concentrations of apitoxin significantly reduced biofilm formation in 14 of the 16 Salmonella strains tested, with significant increases in motility. MIC concentrations of apitoxin destroyed the pre-formed biofilm by 27.66-68.22% (47.00% ± 10.91). The expression of biofilm- and virulence-related genes and small RNAs was differentially regulated according to the strain and the presence of apitoxin. The transcription of the small RNAs dsrA and csrB, related to antimicrobial resistance, was upregulated in the presence of apitoxin. We suggest that apitoxin is a potential antimicrobial substance that could be used in combination with other substances to develop new drugs and sanitizers against food-borne pathogens.}, } @article {pmid31579334, year = {2019}, author = {Kamiya, M and Mori, T and Nomura, M and Inagaki, T and Nonogaki, T and Nagatsu, A and Yamagishi, Y and Mikamo, H and Ikeda, Y}, title = {Tradescantia pallida extract inhibits biofilm formation in Pseudomonas aeruginosa.}, journal = {Nagoya journal of medical science}, volume = {81}, number = {3}, pages = {439-452}, pmid = {31579334}, issn = {2186-3326}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/drug effects ; Plant Extracts/*chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Tradescantia/*chemistry ; }, abstract = {Pseudomonas aeruginosa is capable of biofilm formation. In this study, we investigated the effects of aqueous Tradescantia pallida extract on Pseudomonas aeruginosa growth and biofilm formation. Aqueous Tradescantia pallida extracts significantly inhibited both bacterial growth and biofilm formation. However, methanolic Tradescantia pallida extracts inhibited neither. Aqueous Tradescantia pallida extracts were deactivated by heating but were not deactivated by light exposure. The ingredients retained the inhibitory effect on the bacterial growth and biofilm formation after ultrafiltration of aqueous Tradescantia pallida extract. Furthermore, polyphenol-rich Tradescantia pallida extracts inhibited bacterial growth, thus, polyphenols are possible to be an active ingredient. We observed the biofilm by scanning electron microscopy, and quantitative and qualitative differences in the biofilm and cells morphology. Interestingly, the biofilm treated aqueous Tradescantia pallida extracts remained premature. We postulated that premature biofilm formation was due to the inhibition of swarming motility. Indeed, aqueous Tradescantia pallida extracts inhibited swarming motility. These results demonstrate that Peudomonas aeruginosa growth and biofilm formation are inhibited by aqueous Tradescantia pallida extracts.}, } @article {pmid31578154, year = {2019}, author = {Shi, YJ and Fang, QJ and Huang, HQ and Gong, CG and Hu, YH}, title = {HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida.}, journal = {Veterinary research}, volume = {50}, number = {1}, pages = {76}, pmid = {31578154}, issn = {1297-9716}, support = {41476138//National Natural Science Foundation of China/ ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Edwardsiella/genetics/*pathogenicity/*physiology ; Transcriptome/*physiology ; Virulence ; }, abstract = {Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.}, } @article {pmid31575315, year = {2020}, author = {Namgoong, S and Jung, SY and Han, SK and Kim, AR and Dhong, ES}, title = {Clinical experience with surgical debridement and simultaneous meshed skin grafts in treating biofilm-associated infection: an exploratory retrospective pilot study.}, journal = {Journal of plastic surgery and hand surgery}, volume = {54}, number = {1}, pages = {47-54}, doi = {10.1080/2000656X.2019.1673170}, pmid = {31575315}, issn = {2000-6764}, mesh = {Aged ; Anti-Bacterial Agents/therapeutic use ; *Biofilms ; *Debridement ; Diabetic Foot/*surgery ; Female ; Humans ; Male ; Middle Aged ; Pilot Projects ; Retrospective Studies ; *Skin Transplantation ; Soft Tissue Infections/*therapy ; *Surgical Mesh ; Wound Healing ; }, abstract = {Current treatment guidelines for biofilm-associated infections (BAI) recommend repeated sharp/surgical debridement followed by treatment with antimicrobial agents until the wound becomes self-sustaining in terms of a positive wound-healing trajectory. However, complete removal of a biofilm is unlikely, and biofilms reform rapidly. We have treated BAI in patients with chronic diabetic ulcers using a meshed skin graft combined with negative pressure wound therapy (NPWT) immediately after surgical debridement, rather than waiting until the development of clean and healthy granulation tissue; the purpose of this exploratory study was to report the clinical results of this treatment strategy. This retrospective study included 75 patients with chronic diabetic ulcers who were treated for BAI by using surgical debridement, simultaneous meshed skin grafts, and NPWT. Healing time along with the percentage of complete wound closure within 12 weeks were evaluated; bacteria isolated from the wounds and their relation to the wound healing rate were investigated. All 75 wounds healed successfully, and the mean time for complete wound healing was 3.5 ± 1.8 weeks. In particular, 76% of wounds healed uneventfully without graft loss. A mean of 3.3 bacterial colonies/wound were isolated; however, no significant difference in wound healing was observed between the monomicrobial and polymicrobial groups. This exploratory study suggests that surgical debridement and simultaneous meshed skin grafts combined with NPWT may be successfully used to combat BAI in patients with chronic diabetic ulcers. We look forward to larger pivotal studies to confirm or refute these initially promising findings.}, } @article {pmid31574542, year = {2019}, author = {Meyer, F and Enax, J}, title = {Hydroxyapatite in Oral Biofilm Management.}, journal = {European journal of dentistry}, volume = {13}, number = {2}, pages = {287-290}, pmid = {31574542}, issn = {1305-7456}, abstract = {Particulate hydroxyapatite, Ca5 (PO4)3 (OH), shows a good biocompatibility and is used as a biomimetic ingredient in dental care formulations due to its similarity to human enamel. Numerous studies show its efficiency, for example, in reducing dentin hypersensitivity, and in the remineralization of enamel and dentin. In addition, oral care products with hydroxyapatite improve periodontal health under in vivo conditions. This review article summarizes data on the effects of hydroxyapatite particles in oral biofilm management. Two databases (PubMed and SciFinder) were searched for studies using specific search terms. In contrast to frequently used antibacterial agents for biofilm control, such as chlorhexidine, stannous salts, and quaternary ammonium salts, hydroxyapatite particles in oral care products lead to a reduction in bacterial attachment to enamel surfaces in situ without having pronounced antibacterial effects or showing unwanted side effects such as tooth discoloration. Furthermore, antibacterial agents might lead to dysbiosis of the oral ecology, which was recently discussed regarding pros and cons. Remarkably, the antiadherent properties of hydroxyapatite particles are comparable to those of the gold standard in the field of oral care biofilm management, chlorhexidine in situ. Although biomimetic strategies have been less well analyzed compared with commonly used antibacterial agents in oral biofilm control, hydroxyapatite particles are a promising biomimetic alternative or supplement for oral biofilm management.}, } @article {pmid31574321, year = {2019}, author = {Fugolin, AP and Dobson, A and Huynh, V and Mbiya, W and Navarro, O and Franca, CM and Logan, M and Merritt, JL and Ferracane, JL and Pfeifer, CS}, title = {Antibacterial, ester-free monomers: Polymerization kinetics, mechanical properties, biocompatibility and anti-biofilm activity.}, journal = {Acta biomaterialia}, volume = {100}, number = {}, pages = {132-141}, pmid = {31574321}, issn = {1878-7568}, support = {K02 DE025280/DE/NIDCR NIH HHS/United States ; R35 DE028252/DE/NIDCR NIH HHS/United States ; R01 DE028757/DE/NIDCR NIH HHS/United States ; R01 DE026113/DE/NIDCR NIH HHS/United States ; U01 DE023756/DE/NIDCR NIH HHS/United States ; }, mesh = {Acrylamide/chemistry ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Composite Resins/chemistry ; Esters/*chemistry ; Humans ; Kinetics ; Luminescence ; *Materials Testing ; *Mechanical Phenomena ; Methacrylates/chemistry ; *Polymerization ; Proton Magnetic Resonance Spectroscopy ; Quaternary Ammonium Compounds/chemistry ; Streptococcus mutans/drug effects/physiology ; }, abstract = {OBJECTIVES: Quaternary ammonium (QA) methacrylate monomers have been extensively investigated and demonstrate excellent antibacterial properties. However, the presence of ester bonds makes them prone to degradation in the oral cavity. In this study, ester-free QA monomers based on meth-acrylamides were synthesized and screened for polymerization kinetics, mechanical properties and antibacterial effects.

MATERIALS AND METHODS: Tertiary quaternary ammonium acrylamides (AM) and methacrylamides (MAM) with alkyl side chain lengths of 9 and 14 carbons (C9 and C14) were synthesized and incorporated at 10 wt% into experimental composites based on BisGMA:TEGDMA (1:1), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and 70 wt% barium glass fillers. Analogous methacrylate versions (MA) were used as controls. Degree of conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm[2]) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were measured on 2 × 2 × 25 mm bars in 3-point bending after 24 h dry storage and 7-day storage in water at 37 °C. Antimicrobial properties and biofilm adhesion (fouling) were evaluated by bioluminescence (Luciferase Assay) and biofilm removal by water spray microjet impingement test, respectively. Cytotoxicity was assessed by MTT assay on dental pulp stem cells (DPSC). Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05).

RESULTS: DC was similar for all groups tested (∼70%). Both MAMs and C14-AM presented significantly lower RP. Under dry conditions, FS (110-120 MPa) and E (8-9 GPa) were similar for all groups. After water storage, all materials presented FS/E similar to the control, except for C14-AM (for FS) and C14-MAM (for E), which were lower. All C14 versions were strongly antibacterial, decreasing the titer counts of biofilm by more than two orders of magnitude in comparison to the control. C9 monomers did not present significant antibacterial nor antifouling properties. And biofilms had approximately equivalent adhesion on the C9 composites as on the control. Cytotoxicity did not show significant differences between the MA and AM versions and the control group.

CONCLUSIONS: C14-QA monomers based on methacrylates and meth-acrylamides present strong antibacterial properties, and in general, similar conversion/mechanical properties compared to the methacrylate control.

STATEMENT OF SIGNIFICANCE: This work demonstrates the viability of methacrylamides and acrylamides as potential components in dental restorative materials with antimicrobial properties. The use of ester-free polymerizable functionalities has the potential of improving the degradation resistance of these materials long-term. The use of (meth)acrylamides did not interfere with the antimicrobial potential of quaternary ammonium-based materials.}, } @article {pmid31573125, year = {2019}, author = {Romeu, MJ and Alves, P and Morais, J and Miranda, JM and de Jong, ED and Sjollema, J and Ramos, V and Vasconcelos, V and Mergulhão, FJM}, title = {Biofilm formation behaviour of marine filamentous cyanobacterial strains in controlled hydrodynamic conditions.}, journal = {Environmental microbiology}, volume = {21}, number = {11}, pages = {4411-4424}, doi = {10.1111/1462-2920.14807}, pmid = {31573125}, issn = {1462-2920}, support = {SFRH/BD/140080/2018//FCT/International ; CA15216//ENBA/International ; TD1305//iPROMEDAI/International ; 0302_CVMAR_I_1_P//INTERREG V A Espanha Portugal (POCTEP)/International ; UID/EQU/00511/2019//FCT/MCTES (PIDDAC)/International ; }, mesh = {*Biofilms ; Cyanobacteria/*physiology ; Hydrodynamics ; }, abstract = {Marine biofouling has severe economic impacts and cyanobacteria play a significant role as early surface colonizers. Despite this fact, cyanobacterial biofilm formation studies in controlled hydrodynamic conditions are scarce. In this work, computational fluid dynamics was used to determine the shear rate field on coupons that were placed inside the wells of agitated 12-well microtiter plates. Biofilm formation by three different cyanobacterial strains was assessed at two different shear rates (4 and 40 s[-1]) which can be found in natural ecosystems and using different surfaces (glass and perspex). Biofilm formation was higher under low shear conditions, and differences obtained between surfaces were not always statistically significant. The hydrodynamic effect was more noticeable during the biofilm maturation phase rather than during initial cell adhesion and optical coherence tomography showed that different shear rates can affect biofilm architecture. This study is particularly relevant given the cosmopolitan distribution of these cyanobacterial strains and the biofouling potential of these organisms.}, } @article {pmid31570700, year = {2019}, author = {Jiao, Y and Tay, FR and Niu, LN and Chen, JH}, title = {Advancing antimicrobial strategies for managing oral biofilm infections.}, journal = {International journal of oral science}, volume = {11}, number = {3}, pages = {28}, pmid = {31570700}, issn = {2049-3169}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Anti-Infective Agents/pharmacology/therapeutic use ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Humans ; Mouth/*microbiology ; Plankton ; }, abstract = {Effective control of oral biofilm infectious diseases represents a major global challenge. Microorganisms in biofilms exhibit increased drug tolerance compared with planktonic cells. The present review covers innovative antimicrobial strategies for controlling oral biofilm-related infections published predominantly over the past 5 years. Antimicrobial dental materials based on antimicrobial agent release, contact-killing and multi-functional strategies have been designed and synthesized for the prevention of initial bacterial attachment and subsequent biofilm formation on the tooth and material surface. Among the therapeutic approaches for managing biofilms in clinical practice, antimicrobial photodynamic therapy has emerged as an alternative to antimicrobial regimes and mechanical removal of biofilms, and cold atmospheric plasma shows significant advantages over conventional antimicrobial approaches. Nevertheless, more preclinical studies and appropriately designed and well-structured multi-center clinical trials are critically needed to obtain reliable comparative data. The acquired information will be helpful in identifying the most effective antibacterial solutions and the most optimal circumstances to utilize these strategies.}, } @article {pmid31570396, year = {2019}, author = {Lopes, AA and Yoshii, Y and Yamada, S and Nagakura, M and Kinjo, Y and Mizunoe, Y and Okuda, KI}, title = {Roles of lytic transglycosylases in biofilm formation and β-lactam resistance in methicillin-resistant Staphylococcus aureus.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {12}, pages = {}, pmid = {31570396}, issn = {1098-6596}, abstract = {Staphylococcus aureus is responsible for numerous community outbreaks and is one of the most frequent causes of nosocomial infections with significant morbidity and mortality. While the function of lytic transglycosylases (LTs) in relation to cell division, biofilm formation, and antibiotic resistance has been determined for several bacteria, their role in S. aureus remains largely unknown. The only known LTs in S. aureus are immunodominant staphylococcal antigen A (IsaA) and Staphylococcus epidermidis D protein (SceD). Our study demonstrates that, in a strain of methicillin-resistant S. aureus (MRSA), IsaA and SceD contribute differently to biofilm formation and β-lactam resistance. Deletion of isaA, but not sceD, led to decreased biofilm formation. Additionally, in isaA-deleted strains, β-lactam resistance was significantly decreased compared to that of wild-type strains. Plasmid-based expression of mecA, a major determinant of β-lactam resistance in MRSA, in an isaA-deleted strain did not restore β-lactam resistance, demonstrating that the β-lactam susceptibility phenotype is exhibited by isaA mutant regardless of the production level of PBP2a. Overall, our results suggest that IsaA is a potential therapeutic target for MRSA infections.}, } @article {pmid31565797, year = {2019}, author = {Wang, X and Kong, Y and Zhao, H and Yan, X}, title = {Dependence of the Bacillus subtilis biofilm expansion rate on phenotypes and the morphology under different growing conditions.}, journal = {Development, growth & differentiation}, volume = {61}, number = {7-8}, pages = {431-443}, doi = {10.1111/dgd.12627}, pmid = {31565797}, issn = {1440-169X}, support = {//Harvard University/ ; 11772047//The National Natural Science Foundation of China/ ; 11620101001//The National Natural Science Foundation of China/ ; 2017YFB1002701//National Key R&D Program of China/ ; }, mesh = {Bacillus subtilis/genetics/metabolism/*physiology ; Biofilms/drug effects/*growth & development ; Culture Media/pharmacology ; Fluorescence ; Luminescent Proteins/genetics/metabolism ; Microscopy, Fluorescence/*methods ; Phenotype ; Spores, Bacterial/genetics/metabolism ; Temperature ; Time-Lapse Imaging/*methods ; }, abstract = {Biofilms are communities of tightly associated bacteria encased in an extracellular matrix and attached to surfaces of various objects, such as liquid or solid surfaces. Here we use the multi-channel wide field stereo fluorescence microscope to characterize growth of the Bacillus subtilis biofilm, in which the bacterial strain was triple fluorescence labeled for three main phenotypes: motile, matrix producing and sporulating cells. We used the feature point matching approach analyzing time lapse experimental movies to study the biofilm expansion rate. We found that the matrix producing cells dominate the biofilm expansion, at the biofilm edge, the expansion rate of matrix producing cells was almost the same as the velocity of the whole biofilm; however, the motile and sporulating cells were nearly rest. We also found that the biofilm expansion rate evolution relates to cell differentiation and biofilm morphology, and other micro-environments can influence the biofilm growth, such as nutrient, substrate hardness and colony competition. From our work, we get a deeper understanding of the biofilm growth, which can help us to control and to further disperse the biofilm.}, } @article {pmid31563809, year = {2019}, author = {Han, C and Goodwine, J and Romero, N and Steck, KS and Sauer, K and Doiron, A}, title = {Enzyme-encapsulating polymeric nanoparticles: A potential adjunctive therapy in Pseudomonas aeruginosa biofilm-associated infection treatment.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {184}, number = {}, pages = {110512}, pmid = {31563809}, issn = {1873-4367}, support = {R56 AI127815/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Biocompatible Materials ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry/metabolism ; Particle Size ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry/metabolism/*pharmacology ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Pyruvate Dehydrogenase Complex/*metabolism ; Surface Properties ; Swine ; }, abstract = {Pseudomonas aeruginosa is a pathogen known to be associated with a variety of diseases and conditions such as cystic fibrosis, chronic wound infections, and burn wound infections. A novel approach was developed to combat the problem of biofilm antibiotic tolerance by reverting biofilm bacteria back to the planktonic mode of growth. This reversion was achieved through the enzymatic depletion of available pyruvate using pyruvate dehydrogenase, which induced biofilm bacteria to disperse from the surface-associated mode of growth into the surrounding environment. However, direct use of the enzyme in clinical settings is not practical as the enzyme is susceptible to denaturation under various storage conditions. We hypothesize that by encapsulating pyruvate dehydrogenase into degradable, biocompatible poly(lactic-co-glycolic) acid nanoparticles, the activity of the enzyme can be extended to deplete available pyruvate and induce dispersion of mature Pseudomonas aeruginosa biofilms. Several particle formulations were attempted in order to permit the use of the smallest dose of nanoparticles while maintaining pyruvate dehydrogenase activity for an extended time length. The nanoparticles synthesized using the optimal formulation showed an average size of 266.7 ± 1.8 nm. The encapsulation efficiency of pyruvate dehydrogenase was measured at 17.9 ± 1.4%. Most importantly, the optimal formulation dispersed biofilms and exhibited enzymatic activity after being stored at 37 °C for 6 days.}, } @article {pmid31563763, year = {2020}, author = {Kart, D and Yabanoglu Ciftci, S and Nemutlu, E}, title = {Altered metabolomic profile of dual-species biofilm: Interactions between Proteus mirabilis and Candida albicans.}, journal = {Microbiological research}, volume = {230}, number = {}, pages = {126346}, doi = {10.1016/j.micres.2019.126346}, pmid = {31563763}, issn = {1618-0623}, mesh = {Bacterial Proteins/chemistry/genetics/*metabolism ; Candida albicans/chemistry/genetics/growth & development/*physiology ; Metabolomics ; Proteus mirabilis/chemistry/genetics/growth & development/*physiology ; }, abstract = {In this study, we aimed to determine the interspecies interactions between Proteus mirabilis and Candida albicans. Mono and dual-species biofilms were grown in a microtiter plate and metabolomic analysis of the biofilms was performed. The effects of togetherness of two species on the expression levels of candidal virulence genes and urease and swarming activities of P.mirabilis were investigated. The growth of C.albicans was inhibited by P.mirabilis whereas the growth and swarming activity of P.mirabilis were increased by C.albicans. The inhibition of Candida cell growth was found to be biofilm specific. The alteration was not detected in urease activity. The expressions of EFG1, HWP1 and SAP2 genes were significantly down-regulated, however, LIP1 was upregulated by P.mirabilis. In the presence of P.mirabilis carbonhydrates, amino acids, polyamine and lipid metabolisms were altered in C.albicans. Interestingly, the putrescine level was increased up to 230 fold in dual-species biofilm compared to monospecies C.albicans biofilm. To our knowledge, this is the first study to investigate the impact of each microbial pathogen on the dual microbial environment by integration of metabolomic data.}, } @article {pmid31562986, year = {2019}, author = {Caizán-Juanarena, L and Krug, JR and Vergeldt, FJ and Kleijn, JM and Velders, AH and Van As, H and Ter Heijne, A}, title = {3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging.}, journal = {Water research}, volume = {167}, number = {}, pages = {115059}, doi = {10.1016/j.watres.2019.115059}, pmid = {31562986}, issn = {1879-2448}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Magnetic Resonance Imaging ; }, abstract = {The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R[2] = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL[-1] and 17 μg N μL[-1], respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.}, } @article {pmid31561688, year = {2019}, author = {Jain, AK and Misra, V and Ranjan, N and Jain, SB and Gandhi, S}, title = {Speciation, Biofilm Formation and Antifungal Susceptibility of Candida Isolates from Clinically Diagnosed Patient of UTI in a Tertiary Care Hospital.}, journal = {The Journal of the Association of Physicians of India}, volume = {67}, number = {9}, pages = {42-45}, pmid = {31561688}, issn = {0004-5772}, mesh = {Antifungal Agents/pharmacology/*therapeutic use ; Biofilms/*growth & development ; Candida/*drug effects/isolation & purification ; Humans ; Microbial Sensitivity Tests ; Tertiary Care Centers ; Urinary Tract Infections/*drug therapy/microbiology ; }, abstract = {INTRODUCTION: The incidence of the urinary tract infections caused by Candida species, are becoming more common. Recently, an increase in the incidence of infection caused by fungi especially non albicans candida species (NAC) has been reported. Several virulence factors like biofilm formation, toxin production and presence of adhesins contribute to its pathogenesis.

OBJECTIVES: This study was undertaken to determine species distribution, biofilm formation and in-vitro antifungal susceptibility of candida isolated in our tertiary care hospital.

METHOD: Eighty seven clinical isolates obtained from urine specimens were subjected to wet mount, Gram's stain and cultured on Sabouraud's Dextrose agar (SDA) medium. Conventional method for yeast identification was done. Biofilm forming ability of each isolate was detected using microtitre plate method. Antifungal susceptibility against posaconazole, amphotericin-B, fluconazole, itraconazole, ketoconazole, 5-flucytosine, voriconazole, and caspofungin was tested using Sensititre® Yeastone® (Trek diagnostic systems).

RESULTS AND DISCUSSION: Out of 87 candida isolates, 31.03% (n=27) were C. albicans and 68.97% (n=60) were non albicans candida species (NAC). Among 60 NAC, C. kruseii 29.89% (n=26), C. glabrata 24.14% (n=21), C. tropicalis 14.94% (n=13). Among all isolates, 36.78% (n=32) were biofilm producers and biofilm positivity more among C. albicans 55.56% (n=15) as compared to NAC 28.33% (n=17) (Pvalue<0.002). The maximum positivity was observed with isolates from plastic devices (61.8%). The minimum inhibitory concentrations of all antifungal drugs against all isolates were within susceptible range except for fluconazole which was resistant to C. kruseii.

CONCLUSION: C. albicans remains the major isolate from urine samples and also biofilm formation as a virulence factor might have a higher significance for C. albicans than for NAC and its ability to form biofilm is intricately linked with ability of organisms to adhere, colonize and subsequently cause infection.}, } @article {pmid31561306, year = {2019}, author = {Yu, Z and Li, W and Tan, S}, title = {Real-time monitoring of the membrane biofouling based on spectroscopic analysis in a marine MBBR-MBR (moving bed biofilm reactor-membrane bioreactor) for saline wastewater treatment.}, journal = {Chemosphere}, volume = {235}, number = {}, pages = {1154-1161}, doi = {10.1016/j.chemosphere.2019.07.005}, pmid = {31561306}, issn = {1879-1298}, mesh = {Biodegradation, Environmental ; *Biofilms ; Biofouling/*prevention & control ; *Bioreactors ; *Membranes, Artificial ; Salinity ; Spectrum Analysis ; Wastewater/*chemistry ; Water Purification/methods ; }, abstract = {A MBBR-MBR system has been developed with marine microorganisms enriched for saline wastewater treatment in this work, showing high COD and NH3-N removals. The behaviour of fouling-related components (EPS and SMP) has been studied as functions of operating time (40-90 days), salinity (0-30 g/L NaCl) and backflow ratio (0-300%, from MBR to MBBR). High biodegradability of the MBBR-MBR at optimal conditions can induce more biodegradation of humic acid-like (λex/λem: 350nm/430 nm) and fulvic acid-like (260nm/445 nm) molecules to soluble microbial by-product-like molecules (275nm/325 nm), reducing the membrane biofouling rate. The biodegradation process is suggested by the excitation-emission matrix (EEM) images. In the study of sudden salinity shock, results show that real-time monitoring the concentration of biofoulants is more effective (operative time extended by 60%) than monitoring the transmembrane pressure (operative time extended by 33%) to prevent membrane fouling. Due to an early warning from the real-time monitoring, the coming membrane-fouling is predictable and the operating conditions, such as backflow ratio, can be changed to minimize the biofouling rate.}, } @article {pmid31558046, year = {2019}, author = {Oliveira, GS and Lopes, DRG and Andre, C and Silva, CC and Baglinière, F and Vanetti, MCD}, title = {Multispecies biofilm formation by the contaminating microbiota in raw milk.}, journal = {Biofouling}, volume = {35}, number = {8}, pages = {819-831}, doi = {10.1080/08927014.2019.1666267}, pmid = {31558046}, issn = {1029-2454}, mesh = {Animals ; Biofilms/*growth & development ; Colony Count, Microbial ; Dairying/standards ; *Equipment Contamination ; Food Microbiology ; Manufactured Materials/*microbiology ; *Microbiota ; Milk/*microbiology ; *Stainless Steel ; }, abstract = {Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼10[4] CFU ml[-1] in fresh milk and 10[6] CFU ml[-1] in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 10[5] CFU cm[-2] in the presence of fresh milk, and 10[6] CFU cm[-2] in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.}, } @article {pmid31557551, year = {2019}, author = {Kurt, A and Cilingir, A and Bilmenoglu, C and Topcuoglu, N and Kulekci, G}, title = {Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation.}, journal = {Journal of dentistry}, volume = {90}, number = {}, pages = {103199}, doi = {10.1016/j.jdent.2019.103199}, pmid = {31557551}, issn = {1879-176X}, mesh = {Biofilms ; *Composite Resins ; Dental Polishing/*methods ; Dental Restoration, Permanent/*methods ; Diamond ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Poland ; Surface Properties ; }, abstract = {OBJECTIVES: Both direct and indirect techniques are used for composite resin material (CRM) restorations. Polishing processes are needed in both techniques after intraoral adjustment. However, it is unclear as to which polishing technique should be preferred with respect to decreasing biofilm. The purpose of thisin vitro study was to evaluate the surface properties and Streptococcus mutans biofilm formation on direct and indirect CRMs after using different polishing techniques.

METHODS: Two CRMs (direct and indirect) and four polishing techniques (aluminium oxide discs, diamond polishing paste, aluminium oxide polishing paste, and silicon carbide brush) were evaluated. The specimens were prepared for taking scanning electron microscopy images (n = 2) and determining surface roughness, surface free energy, and bacterial biofilm formation (BBF) with colony-forming unit counting and confocal laser scanning microscopy assays (n = 7). The data were analysed using two-way analysis of variance with Bonferroni as a post hoc test and Pearson's correlation (p < .05).

RESULTS: The surface roughness values in the control group were higher than those in the diamond polishing paste group (p = 0.025), but the values in the aluminium oxide polishing paste and silicon carbide brush groups were comparable with those in the control group (p =  0.156 and p =  1.000, respectively). The highest surface free energy values were recorded in the silicon carbide brush group (p < 0.001), whereas there were no differences found among the other groups (p > 0.05). The highest BBF was seen in the silicon carbide brush (p <  0.001) and direct CRM (p < 0.001) groups.

CONCLUSION: BBF on the surface of direct CRMs differed from that on indirect CRMs after polishing the surface. The tested polishing techniques significantly influenced surface properties and BBF.

CLINICAL SIGNIFICANCE: In situations that require the intraoral adjustment of CRMs, polishing with a diamond polishing paste seems to be a good option to polish the surface of both direct and indirect CRMs because the diamond polishing paste results better in terms of decreasing biofilm formation and improving surface properties.}, } @article {pmid31556843, year = {2019}, author = {Horváthová, T and Bauchinger, U}, title = {Biofilm Improves Isopod Growth Independent of the Dietary Cellulose Content.}, journal = {Physiological and biochemical zoology : PBZ}, volume = {92}, number = {6}, pages = {531-543}, doi = {10.1086/705441}, pmid = {31556843}, issn = {1537-5293}, mesh = {*Animal Feed ; Animals ; *Biofilms ; *Cellulose ; Diet ; Isopoda/*growth & development ; }, abstract = {Cellulose is an abundant source of carbon, accounting for more than 50% of foliage and 90% of woody tissues of plants. Despite the diversity of species that include living or dead plant tissue in their diets, the ability to digest cellulose through self-produced enzymatic machinery is considered rare in the animal kingdom. The majority of animals studied to date rely on the cellulolytic activity of symbiotic microorganisms in their digestive tract, with some evidence for a complementary action of endogenous cellulases. Terrestrial isopods have evolved a lifestyle including feeding on a lignocellulose diet. Whether isopods utilize both external and internal cellulases for digestion of a diet is still not understood. We experimentally manipulated the content of cellulose (30%, 60%, or 90%) and the amount of biofilm (small or large) in the offered food source and quantified growth and cellulolytic activity in the gut of the isopod Porcellio scaber. The presence of a visible biofilm significantly promoted isopod growth, regardless of the cellulose content in the diet. The activity of gut cellulases was not significantly affected by the amount of biofilm or the cellulose content. Our results do not support a significant contribution of either ingested or host enzymes to cellulose utilization in P. scaber. Cellulose might not represent a key nutrient for isopods and does not seem to affect the nutritional value of the diet-associated biofilm. We propose that it is the biofilm community that determines the quality of plant diet in terrestrial isopods and potentially also in other detrital plant feeders.}, } @article {pmid31555777, year = {2019}, author = {Lee, JK and Mereuta, L and Luchian, T and Park, Y}, title = {Antimicrobial peptide HPA3NT3-A2 effectively inhibits biofilm formation in mice infected with drug-resistant bacteria.}, journal = {Biomaterials science}, volume = {7}, number = {12}, pages = {5068-5083}, doi = {10.1039/c9bm01051c}, pmid = {31555777}, issn = {2047-4849}, mesh = {Animals ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects/*growth & development ; Drug Resistance, Bacterial/*drug effects ; Extracellular Polymeric Substance Matrix/metabolism ; Guinea Pigs ; Lipopolysaccharides/metabolism ; Mice ; Microbial Sensitivity Tests ; Peptide Fragments/*pharmacology ; Pseudomonas aeruginosa/cytology/*drug effects/*physiology ; Ribosomal Proteins/chemistry ; }, abstract = {Bacterial biofilms formed through secretion of extracellular polymeric substances (EPS) have been implicated in many serious infections and can increase antibiotic resistance by a factor of more than 1000. Here, we examined the abilities of the antimicrobial peptide HPA3NT3-A2 to inhibit and reduce biofilm formation, eliminate EPS, and suppress inflammation in mice infected with clinical isolates of drug-resistant Pseudomonas aeruginosa strains. HPA3NT3-A2 was developed from a desirable analogue peptide, HPA3NT3, derived from residues 2-20 of the Helicobacter pylori ribosomal protein L1. HPA3NT3-A2 showed stronger activity against planktonic cells (MIC: 8 μM) compared to ciprofloxacin or tobramycin (>512 μM), and a favorable minimum biofilm inhibition and elimination concentration. This peptide also neutralized LPS; decreased levels of EPS; inhibited the production of pro-inflammatory cytokines in the lung, kidney, and spleen; decreased white blood cell counts; and increased survival among infected mice.}, } @article {pmid31553873, year = {2019}, author = {Sommer, R and Rox, K and Wagner, S and Hauck, D and Henrikus, SS and Newsad, S and Arnold, T and Ryckmans, T and Brönstrup, M and Imberty, A and Varrot, A and Hartmann, RW and Titz, A}, title = {Anti-biofilm Agents against Pseudomonas aeruginosa: A Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors.}, journal = {Journal of medicinal chemistry}, volume = {62}, number = {20}, pages = {9201-9216}, pmid = {31553873}, issn = {1520-4804}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Binding Sites ; Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Crystallography, X-Ray ; Drug Design ; Glycosides/*chemistry ; Humans ; Lectins/*antagonists & inhibitors/metabolism ; Mice ; Microsomes, Liver/metabolism ; Molecular Dynamics Simulation ; Pseudomonas aeruginosa/*physiology ; Structure-Activity Relationship ; Sulfonamides/chemistry/metabolism/pharmacology ; }, abstract = {Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with antibiofilm activity. They proved efficient in target binding, were metabolically stable, nontoxic, selective, and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized six new carboxamides and 24 new sulfonamides for a detailed structure-activity relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides, which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency toward the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising antibiofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.}, } @article {pmid31552285, year = {2019}, author = {Kaldhone, PR and Carlton, A and Aljahdali, N and Khajanchi, BK and Sanad, YM and Han, J and Deck, J and Ricke, SC and Foley, SL}, title = {Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development.}, journal = {Frontiers in veterinary science}, volume = {6}, number = {}, pages = {298}, pmid = {31552285}, issn = {2297-1769}, abstract = {Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli. The study characterized IncI1 positive Salmonella isolates and provided evidence about the potential contributions of IncI1 plasmids virulence phenotypes and areas where they do not. These findings should allow for more focused efforts to assess the impact of plasmids on bacterial pathophysiology and human health.}, } @article {pmid31552139, year = {2019}, author = {Willett, JLE and Ji, MM and Dunny, GM}, title = {Exploiting biofilm phenotypes for functional characterization of hypothetical genes in Enterococcus faecalis.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {23}, pmid = {31552139}, issn = {2055-5008}, support = {R01 AI122742/AI/NIAID NIH HHS/United States ; R35 GM118079/GM/NIGMS NIH HHS/United States ; T32 HL007741/HL/NHLBI NIH HHS/United States ; }, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; Computational Biology ; DNA Transposable Elements ; Enterococcus faecalis/*genetics/*growth & development ; *Genes, Bacterial ; Genetic Association Studies/*methods ; Genetic Testing ; Mutagenesis, Insertional ; Phenotype ; }, abstract = {Enterococcus faecalis is a commensal organism as well as an important nosocomial pathogen, and its infections are typically linked to biofilm formation. Nearly 25% of the E. faecalis OG1RF genome encodes hypothetical genes or genes of unknown function. Elucidating their function and how these gene products influence biofilm formation is critical for understanding E. faecalis biology. To identify uncharacterized early biofilm determinants, we performed a genetic screen using an arrayed transposon (Tn) library containing ~2000 mutants in hypothetical genes/intergenic regions and identified eight uncharacterized predicted protein-coding genes required for biofilm formation. We demonstrate that OG1RF_10435 encodes a phosphatase that modulates global protein expression and arginine catabolism and propose renaming this gene bph (biofilm phosphatase). We present a workflow for combining phenotype-driven experimental and computational evaluation of hypothetical gene products in E. faecalis, which can be used to study hypothetical genes required for biofilm formation and other phenotypes of diverse bacteria.}, } @article {pmid31552130, year = {2019}, author = {El-Ezmerli, NF and Gregory, RL}, title = {Effect of nicotine on biofilm formation of Streptococcus mutans isolates from smoking and non-smoking subjects.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1662275}, pmid = {31552130}, issn = {2000-2297}, abstract = {Objectives: To investigate effects of nicotine on biofilm formation of Streptococcus mutans isolates from oral washes of smoker and non-smoker human subjects. Materials and methods: This study was conducted using 60 S. mutans isolates with three S. mutans isolates collected from oral washes of ten smoking subjects and ten from non-smoking subjects. Biofilm was formed by culturing each S. mutans strain (10 μl) in 190 μl of TSB supplemented with 1% sucrose (TSBS) containing 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/ml of nicotine for 24 h in 5% CO2 at 37°C in 96 well microtiter plates. The absorbance values of biofilm were measured at 490 nm in a microplate spectrophotometer. Results: There was a significant effect (p-value < 0.05) of nicotine concentrations and smoking on the growth of biofilm, planktonic cells, and total absorbance, for all strains of S. mutans. Isolates from smokers had significantly more biofilm at 0-16 mg/ml of nicotine compared to those from non-smokers (p-value < 0.0001). Conclusion: S. mutans smoker isolates are more affected by high nicotine concentrations than non-smoker isolates. Clinical Relevance: The use of nicotine products increases the growth of S. mutans and may place tobacco users at risk for dental decay.}, } @article {pmid31551964, year = {2019}, author = {Selvaraj, A and Jayasree, T and Valliammai, A and Pandian, SK}, title = {Myrtenol Attenuates MRSA Biofilm and Virulence by Suppressing sarA Expression Dynamism.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2027}, pmid = {31551964}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a deleterious human pathogen responsible for severe morbidity and mortality worldwide. The pathogen has attained high priority in the World Health Organization (WHO) - Multidrug-resistant (MDR) pathogens list. Emerging MDR strains of S. aureus are clinically challenging due to failure in conventional antibiotic therapy. Biofilm formation is one of the underlying mechanisms behind the antibiotic resistance. Hence, attenuating biofilm formation has become an alternative strategy to control persistent infections. The current study is probably the first that focuses on the antibiofilm and antivirulence potential of myrtenol against MRSA and its clinical isolates. Myrtenol exhibited a concentration-dependent biofilm inhibition without causing any harmful effect on cell growth and viability. Further, microscopic analysis validated the biofilm inhibitory efficacy of myrtenol against MRSA. In addition, myrtenol inhibited the synthesis of major virulence factors including slime, lipase, α-hemolysin, staphyloxanthin and autolysin. Inhibition of staphyloxanthin in turn sensitized the MRSA cells to healthy human blood and hydrogen peroxide (H2O2). Notably, myrtenol treated cells were deficient in extracellular DNA (eDNA) mediated autoaggregation as eDNA releasing autolysis was impaired by myrtenol. Biofilm disruptive activity on preformed biofilms was observed at concentrations higher than minimum biofilm inhibitory concentration (MBIC) of myrtenol. Also, the non-cytotoxic effect of myrtenol on human peripheral blood mononuclear cell (PBMC) was evidenced by trypan blue and Alamar blue assays. Transcriptional analysis unveiled the down-regulation of global regulator sarA and sarA mediated virulence genes upon myrtenol treatment, which is well correlated with results of phenotypic assays. Thus, the results of the present study revealed the sarA mediated antibiofilm and antivirulence potential of myrtenol against MRSA.}, } @article {pmid31551940, year = {2019}, author = {Bottagisio, M and Soggiu, A and Piras, C and Bidossi, A and Greco, V and Pieroni, L and Bonizzi, L and Roncada, P and Lovati, AB}, title = {Proteomic Analysis Reveals a Biofilm-Like Behavior of Planktonic Aggregates of Staphylococcus epidermidis Grown Under Environmental Pressure/Stress.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1909}, pmid = {31551940}, issn = {1664-302X}, abstract = {Prosthetic joint replacement failure has a huge impact on quality of life and hospitalization costs. A leading cause of prosthetic joint infection is bacteria-forming biofilm on the surface of orthopedic devices. Staphylococcus epidermidis is an emergent, low-virulence pathogen implicated in chronic infections, barely indistinguishable from aseptic loosening when embedded in a mature matrix. The literature on the behavior of quiescent S. epidermidis in mature biofilms is scarce. To fill this gap, we performed comparative analysis of the whole proteomic profiles of two methicillin-resistant S. epidermidis strains growing in planktonic and in sessile form to investigate the molecular mechanisms underlying biofilm stability. After 72-h culture of biofilm-forming S. epidermidis, overexpression of proteins involved in the synthesis of nucleoside triphosphate and polysaccharides was observed, whereas planktonic bacteria expressed proteins linked to stress and anaerobic growth. Cytological analysis was performed to determine why planktonic bacteria unexpectedly expressed proteins typical of sessile culture. Images evidenced that prolonged culture under vigorous agitation can create a stressful growing environment that triggers microorganism aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. The choice of a unique late time point provided an important clue for future investigations into the biofilm-like behavior of planktonic cells. Our preliminary results may inform comparative proteomic strategies in the study of mature bacterial biofilm. Finally, there is an increasing number of studies on the aggregation of free-floating bacteria embedded in an extracellular matrix, prompting the need to gain further insight into this mode of bacterial growth.}, } @article {pmid31551455, year = {2019}, author = {Valliammai, A and Sethupathy, S and Priya, A and Selvaraj, A and Bhaskar, JP and Krishnan, V and Pandian, SK}, title = {5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {13744}, pmid = {31551455}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/drug effects/*genetics ; Biofilms/*drug effects ; Gene Expression/drug effects ; Humans ; Hydrogen Peroxide/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests/methods ; Staphylococcal Infections/drug therapy/microbiology ; Trans-Activators/*drug effects ; Up-Regulation/*drug effects ; Virulence/*drug effects ; Virulence Factors ; }, abstract = {Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.}, } @article {pmid31551152, year = {2019}, author = {Qi, M and Li, X and Sun, X and Li, C and Tay, FR and Weir, MD and Dong, B and Zhou, Y and Wang, L and Xu, HHK}, title = {Novel nanotechnology and near-infrared photodynamic therapy to kill periodontitis-related biofilm pathogens and protect the periodontium.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {11}, pages = {1665-1681}, doi = {10.1016/j.dental.2019.08.115}, pmid = {31551152}, issn = {1879-0097}, mesh = {Biofilms ; Humans ; Nanotechnology ; *Periodontitis ; Periodontium ; *Photochemotherapy ; }, abstract = {OBJECTIVE: Periodontal tissue destruction and tooth loss are increasingly a worldwide problem as the population ages. Periodontitis is caused by bacterial infection and biofilm plaque buildup. Therefore, the objectives of this study were to: (1) develop a near-infrared light (NIR)-triggered core-shell nanostructure of upconversion nanoparticles and TiO2 (UCNPs@TiO2), and (2) investigate its inhibitory effects via antibacterial photodynamic therapy (aPDT) against periodontitis-related pathogens.

METHODS: The core β-NaYF4:Yb[3+],Tm[3+] were synthesized via thermal decomposition and further modified with the TiO2 shell via a hydrothermal method. The core-shell structure and the upconversion fluorescence-induced aPDT treatment via 980nm laser were studied. Three periodontitis-related pathogens Streptococcus sanguinis (S. sanguinis), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) were investigated. The killing activity against planktonic bacteria was detected by a time-kill assay. Single species 4-day biofilms on dentin were tested by live/dead staining, colony-forming units (CFU), and metabolic activity.

RESULTS: The hexagonal shaped UCNPs@TiO2 had an average diameter of 39.7nm. UCNPs@TiO2 nanoparticles had positively charged (+12.4mV) surface and were biocompatible and non-cytotoxic. Under the excitation of NIR light (980nm), the core NaYF4:Yb[3+],Tm[3+] UCNPs could emit intense ultraviolet (UV) light, which further triggered the aPDT function of the shell TiO2 via energy transfer, thereby realizing the remarkable antibacterial effects against planktons and biofilms of periodontitis-associated pathogens. NIR-triggered UCNPs@TiO2 achieved much greater reduction in biofilms than control (p<0.05). Biofilm CFU was reduced by 3-4 orders of magnitude via NIR-triggered aPDT, which is significantly greater than that of negative control and commercial aPDT control groups. The killing efficacy of UCNPs@TiO2-based aPDT against the three species was ranked to be: S. sanguinis
SIGNIFICANCE: Upconversion fluorescence-based aPDT achieved strong inhibiting effects against all three species of periodontitis-related pathogens. This novel nanotechnology demonstrated a high promise to inhibit periodontitis, with exciting potential to combat other oral infectious diseases such as deep endodontic infections.}, } @article {pmid31550929, year = {2019}, author = {de Freitas, LM and Lorenzón, EN and Cilli, EM and de Oliveira, KT and Fontana, CR and Mang, TS}, title = {Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.}, journal = {Biofouling}, volume = {35}, number = {7}, pages = {742-757}, doi = {10.1080/08927014.2019.1655548}, pmid = {31550929}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; *Biofilms/drug effects ; Chlorophyllides ; Enterococcus faecalis/drug effects/physiology ; Peptides/*chemistry/pharmacology ; Photochemotherapy ; Photosensitizing Agents/*chemistry/pharmacology ; Porphyrins/chemistry ; }, abstract = {The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies. In this study sub-lethal doses of aPDT (with chlorin-e6 (Ce6-PDT) or methylene blue (MB-PDT)) and the peptides AU (aurein 1.2 monomer) or (AU)2K (aurein 1.2 C-terminal dimer) were combined to evaluate their ability to prevent biofilm development by Enterococcus faecalis. Biofilm formation was assessed by resazurin reduction, confocal microscopy, and infrared spectroscopy. All treatments successfully prevented biofilm development. The (AU)2K dimer had a stronger effect, both alone and combined with aPDT, while the monomer AU had significant activity when combined with Ce6-PDT. Additionally, it is shown that the peptides bind to the lipoteichoic acid of the E. faecalis cell wall, pointing to a possible key mechanism of biofilm inhibition.}, } @article {pmid31550928, year = {2019}, author = {Werner, BG and Wu, JY and Goddard, JM}, title = {Antimicrobial and antifouling polymeric coating mitigates persistence of Pseudomonas aeruginosa biofilm.}, journal = {Biofouling}, volume = {35}, number = {7}, pages = {785-795}, doi = {10.1080/08927014.2019.1660774}, pmid = {31550928}, issn = {1029-2454}, support = {S10 RR025502/RR/NCRR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Pseudomonas aeruginosa/drug effects/*physiology ; }, abstract = {Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing contamination of food can occur due to persistent bacterial biofilms, which can be resistant to conventional cleaning and sanitization. The objective was to characterize the efficacy of a polymeric coating in reducing Pseudomonas aeruginosa biofilm establishment and facilitating its removal. Viable cell density of a 48 h biofilm was reduced by 2.10 log cfu cm[-2] on the coated surface, compared to native polypropylene. Confocal laser scanning and electron microscopy indicated reductions in mature biofilm viability and thickness on the coated material. The antifouling coating improved cleanability, with ∼2.5 log cfu cm[-2] of viable cells remaining after 105 min cleaning by water at 65 °C, compared to 4.5 log cfu cm[-2] remaining on native polypropylene. Such coatings may reduce the persistence of biofilms in food processing environments, in support of reducing food spoilage and waste.}, } @article {pmid31550124, year = {2019}, author = {Hoque, J and Ghosh, S and Paramanandham, K and Haldar, J}, title = {Charge-Switchable Polymeric Coating Kills Bacteria and Prevents Biofilm Formation in Vivo.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {42}, pages = {39150-39162}, doi = {10.1021/acsami.9b11453}, pmid = {31550124}, issn = {1944-8252}, mesh = {Animals ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/*pharmacology/therapeutic use ; Erythrocytes/cytology/drug effects/metabolism ; Escherichia coli/drug effects/physiology ; Female ; Hemolysis/drug effects ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects/pathogenicity ; Mice ; Mice, Inbred BALB C ; Polyethyleneimine/*chemistry/pharmacology/therapeutic use ; Skin/drug effects/pathology ; Staphylococcal Infections/drug therapy/veterinary ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Preventing bacterial biofilm formation on medical devices and implants in vivo still remains a daunting task. Current antibacterial coatings to combat implant-associated infections are generally composed of toxic metals or nondegradable polymers and involve multistep surface modifications. Here, we present a charge-switchable antibacterial and antibiofilm coating based on water-insoluble cationic hydrophobic polymers that are soluble in organic solvents and can be noncovalently coated onto different surfaces. Toward this, a library of quaternary polyethylenimine (QPEI) polymers with an amide or ester group in their pendant alkyl chain was developed. These QPEIs are shown to hydrolyze from active cationic to nontoxic zwitterionic polymers under acidic or enzymatic conditions. Notably, polymers with both zwitterionic and cationic groups, obtained upon partial hydrolysis of QPEIs, are shown to retain their antibacterial activity with much lower toxicity toward mammalian cells. Furthermore, the zwitterionic polymer, a fully hydrolyzed product of the QPEIs, is shown to be nontoxic to mammalian cells in vitro as well as in vivo. The QPEIs, when coated onto surfaces, kill bacteria and prevent formation of biofilms. In an in vivo mice model, the QPEI-coated medical grade catheter is shown to reduce methicillin-resistant Staphylococcus aureus contamination both on the catheter surface and in the adjacent tissues (99.99% reduction compared to a noncoated catheter). Additionally, biofilm formation is inhibited on the catheter surface with negligible inflammation in the adjacent tissue. The above results thus highlight the importance of these polymers to be used as effective antibacterial coatings in biomedical applications.}, } @article {pmid31548684, year = {2019}, author = {Kowalski, CH and Kerkaert, JD and Liu, KW and Bond, MC and Hartmann, R and Nadell, CD and Stajich, JE and Cramer, RA}, title = {Fungal biofilm morphology impacts hypoxia fitness and disease progression.}, journal = {Nature microbiology}, volume = {4}, number = {12}, pages = {2430-2441}, pmid = {31548684}, issn = {2058-5276}, support = {R01 AI130128/AI/NIAID NIH HHS/United States ; P20 GM113132/GM/NIGMS NIH HHS/United States ; R01 AI081838/AI/NIAID NIH HHS/United States ; T32 GM008704/GM/NIGMS NIH HHS/United States ; S10 OD016290/OD/NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; F31 AI138354/AI/NIAID NIH HHS/United States ; T32 HL134598/HL/NHLBI NIH HHS/United States ; }, mesh = {Animals ; Aspergillosis/metabolism ; Aspergillus fumigatus ; Biofilms/*growth & development ; Disease Models, Animal ; *Disease Progression ; Female ; Fungal Proteins ; Fungi/genetics/*metabolism ; Hyphae/genetics ; Hypoxia/*microbiology ; Mice ; Multigene Family ; Virulence ; }, abstract = {Microbial populations form intricate macroscopic colonies with diverse morphologies whose functions remain to be fully understood. Despite fungal colonies isolated from environmental and clinical samples revealing abundant intraspecies morphological diversity, it is unclear how this diversity affects fungal fitness and disease progression. Here we observe a notable effect of oxygen tension on the macroscopic and biofilm morphotypes of the human fungal pathogen Aspergillus fumigatus. A hypoxia-typic morphotype is generated through the expression of a subtelomeric gene cluster containing genes that alter the hyphal surface and perturb interhyphal interactions to disrupt in vivo biofilm and infection site morphologies. Consequently, this morphotype leads to increased host inflammation, rapid disease progression and mortality in a murine model of invasive aspergillosis. Taken together, these data suggest that filamentous fungal biofilm morphology affects fungal-host interactions and should be taken into consideration when assessing virulence and host disease progression of an isolated strain.}, } @article {pmid31548510, year = {2019}, author = {Lin, Q and Sun, H and Yao, K and Cai, J and Ren, Y and Chi, Y}, title = {The Prevalence, Antibiotic Resistance and Biofilm Formation of Staphylococcus aureus in Bulk Ready-To-Eat Foods.}, journal = {Biomolecules}, volume = {9}, number = {10}, pages = {}, pmid = {31548510}, issn = {2218-273X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; Biofilms/drug effects/*growth & development ; China/epidemiology ; Clindamycin/pharmacology ; Dairy Products/microbiology ; *Drug Resistance, Microbial ; Erythromycin/pharmacology ; Food Microbiology/*statistics & numerical data ; Fruit/microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Meat/microbiology ; Penicillins/pharmacology ; Prevalence ; Staphylococcus aureus/drug effects/genetics/*growth & development ; Tetracycline/pharmacology ; Vegetables/microbiology ; }, abstract = {The prevalence of Staphylococcus aureus in 2160 bulk ready-to-eat foods from the Sichuan province of China during 2013-2016 was investigated. The antibiotic resistance and the associated genes, as well as biofilm formation capacity of the S. aureus isolates were measured. Furthermore, the relationship between the antibiotic resistance and the resistant genes was discussed. It was found that 54 S. aureus isolates were recovered, and their prevalence in meat products, dairy, fruit and vegetables, and desserts were 31 (2.6%), six (3.0%), nine (2.2%) and eight (2.3%), respectively. Most strains (52/54) were resistant to at least one of the antibiotics, and 21 isolates were identified as multidrug-resistant (MDR) S. aureus. Three isolates were found to be methicillin-resistant S. aureus. Penicillin, erythromycin, clindamycin, tetracycline and inducible clindamycin resistance were determined as the predominant antibiotics, and the isolates with the phenotypic resistance on these five antibiotics were all determined positive for the resistant gene associated. In total, 33 of 54 S. aureus isolates showed biofilm formation capacity, including two strong biofilm producers, one moderate and 30 weak ones. Two S. aureus isolates with strong biofilm formation abilities showed multi-drug resistance, and one moderate biofilm producer was resistant to two categories of antibiotics.}, } @article {pmid31548325, year = {2019}, author = {Ghimire, N and Pettygrove, BA and Pallister, KB and Stangeland, J and Stanhope, S and Klapper, I and Voyich, JM and Stewart, PS}, title = {Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device.}, journal = {Infection and immunity}, volume = {87}, number = {12}, pages = {}, pmid = {31548325}, issn = {1098-5522}, support = {R01 GM109452/GM/NIGMS NIH HHS/United States ; R56 AI135039/AI/NIAID NIH HHS/United States ; }, mesh = {Anaerobiosis ; Biofilms/*growth & development ; Computational Biology ; Computer Simulation ; Humans ; Immune Evasion/immunology ; Microscopy, Confocal ; Neutrophils/*immunology ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*immunology/microbiology ; Staphylococcal Infections/*immunology ; Staphylococcus aureus/growth & development/*immunology ; }, abstract = {The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil/bacterium number ratio exceeded approximately 1. When preattached bacteria were given a head start and allowed to grow for 3 h prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head-start experiments, aggregates of bacterial biofilm with areas of 50 μm[2] or larger formed, and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O2.}, } @article {pmid31547513, year = {2019}, author = {Erdmann, J and Thöming, JG and Pohl, S and Pich, A and Lenz, C and Häussler, S}, title = {The Core Proteome of Biofilm-Grown Clinical Pseudomonas aeruginosa Isolates.}, journal = {Cells}, volume = {8}, number = {10}, pages = {}, pmid = {31547513}, issn = {2073-4409}, mesh = {Bacterial Proteins/*analysis/genetics/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Genomics ; Mass Spectrometry/methods ; Microbial Sensitivity Tests ; Proteome/*analysis ; Proteomics/methods ; Pseudomonas aeruginosa/chemistry/*metabolism/*physiology ; Transcriptome ; }, abstract = {Comparative genomics has greatly facilitated the identification of shared as well as unique features among individual cells or tissues, and thus offers the potential to find disease markers. While proteomics is recognized for its potential to generate quantitative maps of protein expression, comparative proteomics in bacteria has been largely restricted to the comparison of single cell lines or mutant strains. In this study, we used a data independent acquisition (DIA) technique, which enables global protein quantification of large sample cohorts, to record the proteome profiles of overall 27 whole genome sequenced and transcriptionally profiled clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. Analysis of the proteome profiles across the 27 clinical isolates grown under planktonic and biofilm growth conditions led to the identification of a core biofilm-associated protein profile. Furthermore, we found that protein-to-mRNA ratios between different P. aeruginosa strains are well correlated, indicating conserved patterns of post-transcriptional regulation. Uncovering core regulatory pathways, which drive biofilm formation and associated antibiotic tolerance in bacterial pathogens, promise to give clues to interactions between bacterial species and their environment and could provide useful targets for new clinical interventions to combat biofilm-associated infections.}, } @article {pmid31547458, year = {2019}, author = {Zhang, XY and Sun, K and Abulimiti, A and Xu, PP and Li, ZY}, title = {Microfluidic System for Observation of Bacterial Culture and Effects on Biofilm Formation at Microscale.}, journal = {Micromachines}, volume = {10}, number = {9}, pages = {}, pmid = {31547458}, issn = {2072-666X}, support = {61674046//National Natural Science Foundation of China/ ; 2017TS04//State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology)/ ; }, abstract = {Biofilms exist in the natural world and applied to many industries. However, due to the variety of characteristics caused by their complex components, biofilms can also lead to membrane fouling and recurrent infections which pose threats to human health. So, to make the best use of their advantages and avoid their disadvantages, knowing the best time and methods for improving or preventing biofilm formation is important. In situ observation without fluorescence labeling in microscale and according to a time scale is useful to research biofilm and confine its formation. In this study, we developed a microfluidic system for real-time observation of bacteria culture and biofilms development at microscale. We cultured E. coli ATCC 25922 on a chip at continuous flow of the velocity, which could promote bacterial formation. Biofilms formation under the condition of adding amoxicillin at different times is also discussed. In addition, the mixed strains from sludge were also cultured on chip, and possible factors in biofilm formation are discussed. Our results show that a microfluidic device could culture microorganisms in continuous flow and accelerate them to adhere to the surface, thereby promoting biofilm formation. Overall, this platform is a useful tool in research on initial biofilm formation, which can contribute to preventing biofouling and infections.}, } @article {pmid31547282, year = {2019}, author = {Kerekes, EB and Vidács, A and Takó, M and Petkovits, T and Vágvölgyi, C and Horváth, G and Balázs, VL and Krisch, J}, title = {Anti-Biofilm Effect of Selected Essential Oils and Main Components on Mono- and Polymicrobic Bacterial Cultures.}, journal = {Microorganisms}, volume = {7}, number = {9}, pages = {}, pmid = {31547282}, issn = {2076-2607}, support = {4330//University of Szeged Open Access Fund/ ; }, abstract = {Biofilms are surface-associated microbial communities resistant to sanitizers and antimicrobials. Various interactions that can contribute to increased resistance occur between the populations in biofilms. These relationships are the focus of a range of studies dealing with biofilm-associated infections and food spoilage. The present study investigated the effects of cinnamon (Cinnamomum zeylanicum), marjoram (Origanum majorana), and thyme (Thymus vulgaris) essential oils (EOs) and their main components, i.e., trans-cinnamaldehyde, terpinen-4-ol, and thymol, respectively, on single- and dual-species biofilms of Escherichia coli, Listeria monocytogenes, Pseudomonas putida, and Staphylococcus aureus. In dual-species biofilms, L. monocytogenes was paired with each of the other three bacteria. Minimum inhibitory concentration (MIC) values for the individual bacteria ranged between 0.25 and 20 mg/mL, and trans-cinnamaldehyde and cinnamon showed the highest growth inhibitory effect. Single-species biofilms of L. monocytogenes, P. putida, and S. aureus were inhibited by the tested EOs and their components at sub-lethal concentrations. Scanning electron microscopy images showed that the three-dimensional structure of mature biofilms embedded in the exopolysaccharide matrix disappeared or was limited to micro-colonies with a simplified structure. In most dual-species biofilms, to eliminate living cells from the matrix, concentrations exceeding the MIC determined for individual bacteria were required.}, } @article {pmid31546523, year = {2019}, author = {Das, D and Bhattacharjee, H and Gogoi, K and Das, JK and Misra, P and Dhir, P and Deka, A}, title = {Intraocular lens biofilm formation supported by scanning electron microscopy imaging.}, journal = {Indian journal of ophthalmology}, volume = {67}, number = {10}, pages = {1708-1709}, pmid = {31546523}, issn = {1998-3689}, mesh = {Biofilms/*growth & development ; Cataract Extraction ; Device Removal ; Endophthalmitis/diagnostic imaging/*microbiology ; Eye Infections, Bacterial/diagnostic imaging/*microbiology ; Humans ; Lens Implantation, Intraocular ; Lenses, Intraocular/*microbiology ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; Prosthesis-Related Infections/diagnostic imaging/*microbiology ; Spectrometry, X-Ray Emission ; Staphylococcal Infections/diagnostic imaging/*microbiology ; Staphylococcus epidermidis/*physiology ; }, } @article {pmid31546354, year = {2019}, author = {Eduok, U and Ohaeri, E and Szpunar, J}, title = {Accelerated corrosion of pipeline steel in the presence of Desulfovibrio desulfuricans biofilm due to carbon source deprivation in CO2 saturated medium.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {105}, number = {}, pages = {110095}, doi = {10.1016/j.msec.2019.110095}, pmid = {31546354}, issn = {1873-0191}, mesh = {Biofilms/*growth & development ; Carbon Dioxide/*metabolism ; Corrosion ; Desulfovibrio desulfuricans/*physiology ; *Steel ; }, abstract = {The chemistry of bacterial biofilms as well as the nutritional composition of culture environments may differ at any time within a growth process, especially for SRB consortia within oil wells with limited carbon sources. In the oilfield, the presence of SRB biofilms on surfaces of steel substrates leads to microbiologically influenced corrosion and compromised material integrity. In this work, the survival of SRB cells and their impact on the pipeline steel corrosion within simulated CO2-saturated oilfield-produced water with different concentrations of organic carbon source have been investigated. Cell counts reduced with the level of carbon source reduction (CSR) after incubation but more sessile cells survived at 80% CSR (moderate carbon starvation) compared to 100% CSR (extreme carbon starvation). The energy needed for cellular survival as well as biological support toward MIC could have been harnessed by a combination of extracellular Fe[o] oxidation and intracellular sulfate reduction even after carbon source starvation. Severe anodic steel dissolution was observed at the end of the culture period within the simulated CO2-saturated oilfield-produced water, and this is attributed to SRB-led MIC and CO2 corrosion. Pipeline steel corroded more when cultured within 80% CSR compared to the medium with both lactate and citrate. Steel substrate corroded less with 100% CSR due to severely weakened SRB biofilms from nutrient deprivation.}, } @article {pmid31546042, year = {2019}, author = {Sales, LS and Guimarães, GN and Wijesinghe, GK and Moreira, KMS and Joia, F and Stipp, RN and Rodrigues, LKA and Nobre-Dos-Santos, M and Steiner-Oliveira, C}, title = {Addition of hydrogen peroxide to methylene blue conjugated to β-cyclodextrin in photodynamic antimicrobial chemotherapy in S. mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {28}, number = {}, pages = {226-233}, doi = {10.1016/j.pdpdt.2019.09.004}, pmid = {31546042}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Hydrogen Peroxide/*pharmacology ; Methylene Blue/*pharmacology ; Microbial Viability/drug effects ; Microscopy, Confocal ; Nanoparticles ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Streptococcus mutans/*drug effects ; beta-Cyclodextrins/*pharmacology ; }, abstract = {OBJECTIVE: This study evaluated the effect of hydrogen peroxide addition on β-cyclodextrin-conjugated methylene blue in antimicrobial photodynamic therapy(a-PDT) in S. mutans biofilm model using laser or light emitting diode (LED) (λ = 660 nm).

METHODS: A preliminary assay was performed to evaluate the cytotoxicity of hydrogen peroxide in oral fibroblasts by the colorimetric method (MTT). Afterwards, groups were divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (methylene blue/β-cyclodextrin), H (Hydrogen Peroxide at 40 μM), PH, L (Laser), LP, LH (Laser+Hydrogen Peroxide), LPH, LED, LEDP, LEDH, and LEDPH. The biofilm was formed in 24 h with BHI + 1% sucrose (w/v). Light irradiations were conducted with laser, 9 J, 323 J/cm[2], 113 s or with LED, 8.1 J, 8.1 J/cm[2] for 90 s. Microbial reduction was evaluated by counting the viable microorganisms of the biofilm after the respective treatments, in a selective culture medium, and laser confocal microscopy evaluation.

RESULTS: LP, LH, LPH, LEDP, LEDH, and LEDPH groups statistically reduced the counts of S.mutans compared with the C group and the log reductions were of 1.87, 1.94, 2.19, 0.91, 0.92, and 1.33, respectively; the addition of hydrogen peroxide did not potentiate the microbial reductions (LPH and LEDPH) compared with the LP and LEDP groups.

CONCLUSION: The association of hydrogen peroxide with the conjugated β-cyclodextrin nanoparticle as photosensitizer did not result in an enhanced effect of a-PDT; hydrogen peroxide behaved as a photosensitizer, since it reduced the number of S. mutans when associated with laser light.}, } @article {pmid31546040, year = {2019}, author = {Ram, MK and Naveen Kumar, BT and Poojary, SR and Abhiman, PB and Patil, P and Ramesh, KS and Shankar, KM}, title = {Evaluation of biofilm of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer (BLOCH, 1790).}, journal = {Fish & shellfish immunology}, volume = {94}, number = {}, pages = {746-751}, doi = {10.1016/j.fsi.2019.09.053}, pmid = {31546040}, issn = {1095-9947}, mesh = {Administration, Oral ; Animals ; Bacterial Vaccines/administration & dosage/*pharmacology ; *Bass ; *Biofilms ; Fish Diseases/*prevention & control ; Hot Temperature ; Vaccination/*veterinary ; Vaccines, Inactivated/administration & dosage/pharmacology ; Vibrio/immunology/*physiology ; Vibrio Infections/prevention & control/*veterinary ; }, abstract = {The present study evaluated the biofilm (BF) of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer. An 80-day experiment was carried out in circular fiber-reinforced plastic (FRP) tanks using free cell (FC) and BF of Vibrio anguillarum with triplicate in each. Heat-inactivated FC and BF cells at 10[7], 10[10] and 10[13] CFU/g fish/d were fed to fish for 20 days, agglutination antibody titer estimated at each 10 days interval up to 60-day post vaccination. As compared to FC and control there was a significant increase in agglutinating antibody titer in the biofilm vaccinated fishes. Among the 3 doses, BF at 10[10] cfu/g fish/d was considered the ideal dose for vaccination. Relative percentage survival (RPS) was higher in biofilm vaccinated fish (85.4%) compared to that with free cells (27.0%). The study demonstrated the better performance of V. anguillarum biofilm oral vaccine compared that with free cell vaccine in L. calcarifer. The study further supports better performance of biofilm vaccine model with one more bacterial pathogen in a high carnivore fish.}, } @article {pmid31546000, year = {2019}, author = {Campos-Silva, R and Brust, FR and Trentin, DS and Macedo, AJ}, title = {Alternative method in Galleria mellonella larvae to study biofilm infection and treatment.}, journal = {Microbial pathogenesis}, volume = {137}, number = {}, pages = {103756}, doi = {10.1016/j.micpath.2019.103756}, pmid = {31546000}, issn = {1096-1208}, mesh = {Animals ; Biofilms/*growth & development ; Colony Count, Microbial ; Disease Models, Animal ; Larva/*microbiology ; Moths/*microbiology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/pathogenicity ; }, abstract = {In vivo studies are crucial decision-maker step in order to translate in vitro data to an applied therapy. Considering this we describe a simple method that analyzes and quantifies biofilm formation inside the Galleria mellonella larvae. Toothbrush bristles were employed as an abiotic surface to mimic a medical device. A standardized inoculum of Staphylococcus aureus was systemically injected in the larvae together with the insertion of a bristle in the last proleg pair. After incubation adhered cells were detached from bristles and quantified by colony-forming units (CFU) counting using staphylococci-selective medium. About 3 × 10[6] CFU of S. aureus were recovered from bristles and scanning electron microscopy (SEM) images confirmed biofilm formation. Control group did not show adherent bacteria, as demonstrated by absence of CFU counting and SEM images, indicating that the insertion procedure is free of bacterial contamination. We present a feasible method to evaluate bacterial biofilm formation in vivo that in the near future can be used to evaluate antibiofilm compounds.}, } @article {pmid31543874, year = {2019}, author = {De Carolis, E and Soldini, S and La Rosa, M and Nucci, F and Posteraro, B and Sanguinetti, M}, title = {BIOF-HILO Assay: A New MALDI-TOF Mass Spectrometry Based Method for Discriminating Between High- and Low-Biofilm-Producing Candida parapsilosis Isolates.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2046}, pmid = {31543874}, issn = {1664-302X}, abstract = {Candida parapsilosis is the most frequent cause of catheter-related candidemia among non-Candida albicans species. This may be related to intrinsic capabilities as adhering and forming a biofilm on abiotic surfaces such as on medical devices. As previously demonstrated, patients infected with high biofilm-producing C. parapsilosis isolates had a greater mortality risk compared to patients infected with low biofilm-producing C. parapsilosis isolates. We developed the BIOF-HILO assay, a MALDI-TOF mass spectrometry (MS)-based assay, which compares mass spectra obtained from attached and suspended isolate cells during the early (i.e., 3-h) adhesion phase of in vitro biofilm formation. The composite correlation index (CCI) analysis was used to discriminate between mass spectra differences of the two cell types, classifying all 50 C. parapsilosis clinical isolates, included in the study, after only 3-h of testing, in high or low biofilm producers. All high (n = 25) or low (n = 25) biofilm producers had, according to CCI mass spectra comparison values, higher or lower than one CCI ratios, which were obtained by dividing the CCIsuspended cells by the CCIattached cells. In conclusion, the BIOF-HILO assay allows a rapid categorization of C. parapsilosis clinical isolates in high or low biofilm producers. This information, if timely provided to physicians, may improve treatment outcomes in patients with C. parapsilosis candidemia.}, } @article {pmid31543873, year = {2019}, author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M}, title = {Corrigendum: The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {2014}, doi = {10.3389/fmicb.2019.02014}, pmid = {31543873}, issn = {1664-302X}, abstract = {[This corrects the article DOI: 10.3389/fmicb.2019.01499.].}, } @article {pmid31543653, year = {2019}, author = {Kitti, T and Seng, R and Thummeepak, R and Boonlao, C and Jindayok, T and Sitthisak, S}, title = {Biofilm Formation of Methicillin-resistant Coagulase-Negative Staphylococci Isolated from Clinical Samples in Northern Thailand.}, journal = {Journal of global infectious diseases}, volume = {11}, number = {3}, pages = {112-117}, pmid = {31543653}, issn = {0974-777X}, abstract = {BACKGROUND: Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are multidrug-resistant bacteria that are difficult to treat because of their ability to form biofilms.

OBJECTIVES: In the present study, we evaluated the antibiotic-resistant phenotypes, biofilm-forming ability, and biofilm associated genes of 55 clinical MR-CoNS isolates obtained from two hospitals in Thailand.

MATERIALS AND METHODS: MALDI-TOF-MS and tuf gene sequencing were performed to determine the species of all isolates. Biofilm production was determined using Congo red agar (CRA) and the microtiter plate (MTP) assay. Biofilm-associated genes were characterized using polymerase chain reaction (PCR).

RESULTS: Among the 55 MR-CoNS isolates, five species were identified as Staphylococcus haemolyticus (34.5%), Staphylococcus epidermidis (32.7%), Staphylococcus capitis (18.2%), Staphylococcus cohnii (9.1%), and Staphylococcus hominis (5.5%). The antimicrobial susceptibility pattern of MR-CoNS isolates indicated high resistance to cefoxitin (100%), penicillin (98.2%), erythromycin (96.4%), ciprofloxacin (67.3%), sulfamethoxazole/trimethoprim (67.3%), gentamicin (67.3%), and clindamycin (63.6%). All the isolates were susceptible to vancomycin and linezolid. The biofilm production was detected in 87.3% isolates through the CRA method and in 38.1% isolates through the MTP assay. The prevalence rates of icaAD, bap, fnbA, and cna were 18.2%, 12.7%, 47.3%, and 27.3%, respectively. There were significant differences in the presence of these biofilm-associated genes among the MR-CoNS isolates. Moreover, quantitative biofilm formation was significantly different among MR-CoNS species.

CONCLUSION: The present study revealed that biofilm-associated genes are important for biofilm biomass in MR-CoNS isolates, and the findings of this study are essential for finding new strategies to control biofilm formation and prevent the spread of MR-CoNS infectious diseases.}, } @article {pmid31542601, year = {2019}, author = {Mitchell, K and Lima, AT and Van Cappellen, P}, title = {Selenium in buoyant marine debris biofilm.}, journal = {Marine pollution bulletin}, volume = {149}, number = {}, pages = {110562}, doi = {10.1016/j.marpolbul.2019.110562}, pmid = {31542601}, issn = {1879-3363}, mesh = {*Biofilms/classification/growth & development ; *Environmental Monitoring ; Oceans and Seas ; Plastics/chemistry ; Seawater/*chemistry ; Selenium/*analysis ; Trace Elements/analysis ; Waste Products/*analysis ; Water Pollutants, Chemical/*analysis ; }, abstract = {Marine debris is widespread in all the world's oceans. Currently little is understood about how marine debris affects the chemistry of the surface oceans, particularly trace elements that can adsorb to the surface of marine debris, especially plastic debris, or be taken up by biofilms and algae growing on the surface of marine debris. Selenium (Se) is a micronutrient that is essential to all living organisms. Average seawater Se concentrations in the modern ocean are <1 nM. Here we measure the concentration of Se in surface water and one deep water sample and the concentration of Se found in algae/biofilms growing on the surface of macro-debris collected in October of 2012. Concentrations of Se in biofilm varied more according to the type of biofilm rather than the type of plastic. However, further Se measurements are needed for more conclusive results.}, } @article {pmid31542551, year = {2019}, author = {Acevedo Alonso, V and Lackner, S}, title = {Membrane Aerated Biofilm Reactors - How longitudinal gradients influence nitrogen removal - A conceptual study.}, journal = {Water research}, volume = {166}, number = {}, pages = {115060}, doi = {10.1016/j.watres.2019.115060}, pmid = {31542551}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors ; Denitrification ; *Nitrogen ; Waste Disposal, Fluid ; }, abstract = {Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.}, } @article {pmid31541515, year = {2019}, author = {Amaechi, BT and Abdul Azees, PA and Menon, S and Kasundra, H}, title = {In vitro evaluation of the effects of Ultrasound Tongue Scraper on bacteria and biofilm formation.}, journal = {Journal of investigative and clinical dentistry}, volume = {10}, number = {4}, pages = {e12471}, doi = {10.1111/jicd.12471}, pmid = {31541515}, issn = {2041-1626}, support = {//Starmoon/ ; }, mesh = {Bacteria ; *Biofilms ; Microscopy, Confocal ; *Tannerella forsythia ; }, abstract = {AIM: Oral malodor is a common condition caused by some Gram-negative oral bacteria, among which are the 3 red complex bacteria (RCB). The present study investigated the effectiveness of the Ultrasound Tongue Scraper (UTS) to disrupt the structural morphology of the bacteria and their biofilm.

METHODS: While developing over 72 hours, multispecies biofilms of RCB (Porphromonas gingivalis, Tryponema denticola, Tannerella forsythia) were treated every 24 hours with 1.6-MHz ultrasound waves generated with UTS. An untreated group served as controls. Confocal laser scanning microscopy was used to determine the biofilm thickness, biomass and live : dead cell ratio at each time point (24, 48 and 72 hours). Biofilm morphology and bacteria ultrastructure were viewed using scanning/transmission electron microscopy, respectively. Data were analyzed using ANOVA and Tukey tests.

RESULTS: At each time point, the 3 variables were significantly lower in treated samples than the untreated. Significant biofilm disruption was observed in treated samples at each time period while the untreated had intact biofilm morphology. Cells in treated samples showed disrupted cell wall, cytoplasmic material, huge vacuoles and heterogeneity in electron density, while these cell organelles remained intact in untreated samples.

CONCLUSION: The UTS has an inhibitory effect on RCB and could be useful for oral malodor management.}, } @article {pmid31540110, year = {2019}, author = {Li, S and Wang, Y and Li, X and Lee, BS and Jung, S and Lee, MS}, title = {Enhancing the Thermo-Stability and Anti-Biofilm Activity of Alginate Lyase by Immobilization on Low Molecular Weight Chitosan Nanoparticles.}, journal = {International journal of molecular sciences}, volume = {20}, number = {18}, pages = {}, pmid = {31540110}, issn = {1422-0067}, support = {NRF-2016R1A5A1011974//National Research Foundation of Korea (NRF)/ ; MBSMAT-2019-02//Key Lab of Marine Bioactive Substance and Modern Analytical Technique (SOA)/ ; ZR2019BD027//Shandong Provincial Natural Science Foundation/ ; KLGGOUC201703//Open Research Fund Program of Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology (Ocean University of China)/ ; }, mesh = {Alginates/*chemistry ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Chitosan/*chemistry ; Drug Resistance, Microbial ; Enzyme Stability ; Enzymes, Immobilized/chemistry/metabolism/pharmacology ; Extracellular Polymeric Substance Matrix/chemistry ; Molecular Weight ; Nanoparticles/*chemistry/ultrastructure ; Polysaccharide-Lyases/chemistry/metabolism/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Temperature ; }, abstract = {Bacterial biofilm causes severe antibiotic resistance. An extracellular polymeric substance (EPS) is the main component in the bacterial biofilm. Alginate is a key EPS component in the biofilm of Pseudomonas aeruginosa and responsible for surface adhesion and stabilization of biofilm. Alginate lyase has emerged as an efficient therapeutic strategy targeting to degrade the alginate in the biofilm of P. aeruginosa. However, the application of this enzyme is limited by its poor stability. In this study, chitosan nanoparticles (CS-NPs) were synthesized using low molecular weight chitosan and alginate lyase Aly08 was immobilized on low molecular weight chitosan nanoparticles (AL-LMW-CS-NPs). As a result, the immobilization significantly enhanced the thermal stability and reusability of Aly08. In addition, compared with free Aly08, the immobilized AL-LMW-CS-NPs exhibited higher efficiency in inhibiting biofilm formation and interrupting the established mature biofilm of P. aeruginosa, which could reduce its biomass and thickness confirmed by confocal microscopy. Moreover, the biofilm disruption greatly increased the antibiotic sensitivity of P. aeruginosa. This research will contribute to the further development of alginate lyase as an anti-biofilm agent.}, } @article {pmid31539943, year = {2019}, author = {Wang, X and Liu, B and Pan, X and Gadd, GM}, title = {Transport and retention of biogenic selenium nanoparticles in biofilm-coated quartz sand porous media and consequence for elemental mercury immobilization.}, journal = {The Science of the total environment}, volume = {692}, number = {}, pages = {1116-1124}, doi = {10.1016/j.scitotenv.2019.07.309}, pmid = {31539943}, issn = {1879-1026}, mesh = {Biofilms ; Hydrophobic and Hydrophilic Interactions ; Mercury/*analysis ; *Models, Chemical ; Nanoparticles/*analysis/chemistry ; Quartz ; Selenium/*analysis/chemistry ; }, abstract = {Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg[0]) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg[0]. It is proposed that oxidative complexation between Hg[0] and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg[2+]-thiolate complexes and HgS during the binding of Hg[0] with BioSeNPs. The formation of mercury selenide was also involved in Hg[0] immobilization in the porous quartz sand system.}, } @article {pmid31539312, year = {2021}, author = {Cai, X and Yao, L and Sheng, Q and Jiang, L and Wang, T and Dahlgren, RA and Deng, H}, title = {Influence of a biofilm bioreactor on water quality and microbial communities in a hypereutrophic urban river.}, journal = {Environmental technology}, volume = {42}, number = {9}, pages = {1452-1460}, doi = {10.1080/09593330.2019.1670267}, pmid = {31539312}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; *Rivers ; Water Quality ; }, abstract = {Biofilms play an important role in degradation, transformation and assimilation of anthropogenic pollutants in aquatic ecosystems. In this study, we assembled a tubular bioreactor containing a biofilm substrate and aeration device, which was introduced into mesocosms to explore the effects of bioreactor on physicochemical and microbial characteristics of a hypereutrophic urban river. The biofilm bioreactor greatly improved water quality, especially by decreasing dissolved inorganic nitrogen (DIN) concentrations, suggesting that biofilms were the major sites of nitrification and denitrification with an oxygen concentration gradient. The biofilm bioreactor increased the abundance of planktonic bacteria, whereas diversity of the planktonic microbial community decreased. Sequencing revealed that Proteobacteria, Bacteroidetes, Planctomycetes, and Actinobacteria were the four predominant phyla in the planktonic microbial community, and the presence of the biofilm bioreactor increased the relative abundance of Proteobacteria. Variations in microbial communities were most strongly affected by the presence of the biofilm bioreactor, as indicated by principal component analysis (PCA) and redundancy analysis (RDA). This study provides valuable insights into changes in ecological characteristics associated with self-purification processes in hypereutrophic urban rivers, and may be of important for the application of biofilm bioreactor in natural urban river.}, } @article {pmid31537970, year = {2019}, author = {Bali, EB and Türkmen, KE and Erdönmez, D and Sağlam, N}, title = {Comparative Study of Inhibitory Potential of Dietary Phytochemicals Against Quorum Sensing Activity of and Biofilm Formation by Chromobacterium violaceum 12472, and Swimming and Swarming Behaviour of Pseudomonas aeruginosa PAO1.}, journal = {Food technology and biotechnology}, volume = {57}, number = {2}, pages = {212-221}, pmid = {31537970}, issn = {1330-9862}, abstract = {Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. Alternative treatments are needed to prevent recurrent or chronic infections caused by multi-resistant pathogens. Therefore, the aim of this study is to investigate and compare the inhibitory potential of the dietary phytochemicals: curcumin, quercetin, apigenin, pyrogallol, gallic acid and luteolin against QS of and biofilm formation by Chromobacterium violaceum ATCC 12472 and the swimming and swarming abilities of Pseudomonas aeruginosa PAO1. Anti-QS potential of the phytochemicals was evaluated qualitatively and quantitatively using C. violaceum via the disk diffusion assay based on violacein pigment inhibition at the subminimal inhibitory concentrations ranging from 46.87 to 750 µg/mL. The results of anti-QS and antibiofilm activities on C. violaceum demonstrated that all the phytochemicals except pyrogallol and gallic acid inhibited violacein production (from (11.0±0.1) to (88.2±0.1) %) in a concentration-dependent manner. In addition, the biofilm formation was also significantly inhibited (p<0.05) in the presence of all the phytochemicals ((1.38±0.08)-(84.2±0.2) %). In the present study, the results revealed that quercetin, curcumin, apigenin and luteolin could be promising QS and biofilm inhibitory agents against the C. violaceum 12472 biosensor system. Our findings also suggest that all the phytochemicals, especially curcumin, quercetin and pyrogallol, might be anti-pathogenic agents against P. aeruginosa PAO1 infections due to the ability to control QS. However, more comprehensive studies at the molecular level, explaining their anti-QS mechanisms, need to be conducted to confirm these results and identify the genes involved.}, } @article {pmid31536440, year = {2019}, author = {Abushahba, F and Söderling, E and Aalto-Setälä, L and Hupa, L and Närhi, TO}, title = {Air Abrasion With Bioactive Glass Eradicates Streptococcus mutans Biofilm From a Sandblasted and Acid-Etched Titanium Surface.}, journal = {The Journal of oral implantology}, volume = {45}, number = {6}, pages = {444-450}, doi = {10.1563/aaid-joi-D-18-00324}, pmid = {31536440}, issn = {0160-6972}, mesh = {Biofilms ; Humans ; Microscopy, Electron, Scanning ; *Peri-Implantitis ; *Streptococcus mutans ; Surface Properties ; Titanium ; }, abstract = {Streptococcus mutans is able to form a high-affinity biofilm on material surfaces. S mutans has also been detected around infected implants. Bioactive glasses (BAGs) have been shown to possess antibacterial effects against S mutans and other microorganisms. This in vitro study was performed to investigate the influence of BAG air abrasion on S mutans biofilm on sandblasted and acid-etched titanium surfaces. Sandblasted and acid-etched commercially pure titanium discs were used as substrates for bacteria (n = 107). The discs were immersed in an S mutans solution and incubated for 21 hours to form an S mutans biofilm. Twenty colonized discs were subjected to air abrasion with Bioglass 45S5 (45S5 BAG), experimental zinc oxide containing BAG (Zn4 BAG), and inert glass. After the abrasion, the discs were incubated for 5 hours in an anaerobic chamber followed by an assessment of viable S mutans cells. Surface morphology was evaluation using scanning electron microscopy (n = 12). The thrombogenicity of the glass particle-abraded discs (n = 75) was evaluated spectrophotometrically using whole-blood clotting measurement at predetermined time points. Air abrasion with 45S5 and Zn4 BAG eradicated S mutans biofilm. Significantly fewer viable S mutans cells were found on discs abraded with the 45S5 or Zn4 BAGs compared with the inert glass (P < .001). No significant differences were found in thrombogenicity since blood clotting was achieved for all substrates at 40 minutes. Air abrasion with BAG particles is effective in the eradication of S mutans biofilm from sandblasted and acid-etched titanium surfaces. Zn4 and 45S5 BAGs had similar biofilm-eradicating effects, but Zn4 BAG could be more tissue friendly. In addition, the steady release of zinc ions from Zn4 may enhance bone regeneration around the titanium implant and may thus have the potential to be used in the treatment of peri-implantitis. The use of either BAGs did not enhance the speed of blood coagulation.}, } @article {pmid31535222, year = {2019}, author = {Mello, DCR and de Oliveira, JR and Cairo, CAA and Ramos, LSB and Vegian, MRDC and de Vasconcellos, LGO and de Oliveira, FE and de Oliveira, LD and de Vasconcellos, LMR}, title = {Titanium alloys: in vitro biological analyzes on biofilm formation, biocompatibility, cell differentiation to induce bone formation, and immunological response.}, journal = {Journal of materials science. Materials in medicine}, volume = {30}, number = {9}, pages = {108}, pmid = {31535222}, issn = {1573-4838}, support = {2012/20311-8//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; }, mesh = {Alloys/chemistry/*pharmacology ; Animals ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/physiology ; Cell Differentiation/*drug effects ; Cells, Cultured ; Materials Testing ; Mice ; Microbial Sensitivity Tests ; Osteoblasts/cytology/drug effects/physiology ; Osteogenesis/*drug effects ; Pseudomonas/drug effects/physiology ; RAW 264.7 Cells ; Staphylococcus aureus/drug effects/physiology ; Streptococcus/drug effects/physiology ; Surface Properties ; Titanium/chemistry/*pharmacology ; }, abstract = {Biological effects of titanium (Ti) alloys were analyzed on biofilms of Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Streptococcus sanguinis, as well as on osteoblast-like cells (MG63) and murine macrophages (RAW 264.7). Standard samples composed of aluminum and vanadium (Ti-6Al-4V), and sample containing niobium (Ti-35Nb) and zirconium (Ti-13Nb-13Zr) were analyzed. Monomicrobial biofilms were formed on the Ti alloys. MG63 cells were grown with the alloys and the biocompatibility (MTT), total protein (TP) level, alkaline phosphatase (ALP) activity, and mineralization nodules (MN) formation were verified. Levels of interleukins (IL-1β and IL-17), tumor necrosis factor alpha (TNF-α), and oxide nitric (NO) were checked, from RAW 264.7 cells supernatants. Data were statically analyzed by one-way analysis of variance (ANOVA) and Tukey's test, or T-test (P ≤ 0.05). Concerning the biofilm formation, Ti-13Nb-13Zr alloy showed the best inhibitory effect on E. faecalis, P. aeruginosa, and S. aureus. And, it also acted similarly to the Ti-6Al-4V alloy on C. albicans and Streptococcus spp. Both alloys were biocompatible and similar to the Ti-6Al-4V alloy. Additionally, Ti-13Nb-13Zr alloy was more effective for cell differentiation, as observed in the assays of ALP and MN. Regarding the stimulation for release of IL-1β and TNF-α, Ti-35Nb and Ti-13Nb-13Zr alloys inhibited similarly the synthesis of these molecules. However, both alloys stimulated the production of IL-17. Additionally, all Ti alloys showed the same effect for NO generation. Thus, Ti-13Nb-13Zr alloy was the most effective for inhibition of biofilm formation, cell differentiation, and stimulation for release of immune mediators.}, } @article {pmid31535132, year = {2020}, author = {Oktay, EA and Ersahan, S and Sabuncuoglu, FA and Tort, H and Karaoglanoglu, S}, title = {Impact of various finishing and polishing techniques and composite materials on Candida albicans biofilm formation.}, journal = {Medical mycology}, volume = {58}, number = {5}, pages = {698-702}, doi = {10.1093/mmy/myz095}, pmid = {31535132}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Candida albicans/*growth & development ; Cell Adhesion ; *Composite Resins ; *Dental Polishing ; Materials Testing ; Surface Properties ; }, abstract = {Candida albicans biofilms are commonly associated with severe oral infections. In dentistry, prosthetic and restorative materials are potential structures for the adhesion of C. albicans facilitating the formation of Candida biofilm and infection. Three composite resins (Charisma Classic, Sonic Fill, Estelite ∑ Quick) and two finishing-polishing systems (Biscover LV, Dental Finishing Disc) were evaluated for Candida biofilm formation. A Candida biofilm assay showed that both the resin and the finishing/polishing procedures affect Candida biofilm formation. Specifically, Candida biofilm formation was significantly lower in Sonic Fill resin than both Charisma Classic and Estelite ∑ Quick (P = .021). The type of finishing and polishing procedure also significantly affected the Candida biofilm formation to composite material (P < .001). Candida biofilm formation was more advanced after Biscover LV procedure than Dental Finishing Disc procedure.}, } @article {pmid31534648, year = {2019}, author = {Craft, KM and Nguyen, JM and Berg, LJ and Townsend, SD}, title = {Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype.}, journal = {MedChemComm}, volume = {10}, number = {8}, pages = {1231-1241}, pmid = {31534648}, issn = {2040-2511}, support = {T32 GM065086/GM/NIGMS NIH HHS/United States ; }, abstract = {Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.}, } @article {pmid31533204, year = {2019}, author = {Weng, PL and Ramli, R and Hamat, RA}, title = {Antibiotic Susceptibility Patterns, Biofilm Formation and esp Gene among Clinical Enterococci: Is There Any Association?.}, journal = {International journal of environmental research and public health}, volume = {16}, number = {18}, pages = {}, pmid = {31533204}, issn = {1660-4601}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Cross-Sectional Studies ; Enterococcus faecalis/genetics/*physiology ; Enterococcus faecium/genetics/*physiology ; Malaysia ; Membrane Proteins/*genetics/metabolism ; Microbial Sensitivity Tests ; }, abstract = {Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X[2] = 4.581, p = 0.027; and X[2] = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.}, } @article {pmid31533083, year = {2019}, author = {Preetham, E and Rubeena, AS and Vaseeharan, B and Chaurasia, MK and Arockiaraj, J and Olsen, RE}, title = {Anti-biofilm properties and immunological response of an immune molecule lectin isolated from shrimp Metapenaeus monoceros.}, journal = {Fish & shellfish immunology}, volume = {94}, number = {}, pages = {896-906}, doi = {10.1016/j.fsi.2019.09.032}, pmid = {31533083}, issn = {1095-9947}, mesh = {Aeromonas hydrophila/physiology ; Animals ; Biofilms/*drug effects ; Enterococcus faecalis/physiology ; Hemolymph/chemistry ; Lectins/*immunology/pharmacology ; Penaeidae/*immunology/physiology ; Staphylococcus aureus/physiology ; Vibrio parahaemolyticus/physiology ; }, abstract = {The study is carried out to understand the antimicrobial and immunological response of a potential immune molecule lectin, MmLec isolated from haemolymph of Speckled shrimp, Metapenaeus monoceros. MmLec was purified using mannose coupled Sepharose CL-4B affinity chromatography, which was further subjected on SDS-PAGE to ascertain the distribution of their molecular weight. Sugar binding specificity assay was conducted at various pH and temperatures to investigate the binding affinity of MmLec towards the specific carbohydrate molecule. Functional analysis of immune molecule MmLec included haemagglutination assays performed using human erythrocytes and yeast agglutination activity against Saccharomyces cerevisiae which, were analyzed using light microscopy. In order to study the antimicrobial activity, two Gram-negative (Vibrio parahaemolyticus and Aeromonas hydrophila) and two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria were treated with purified MmLec. Moreover, these bacterial species were also treated at different concentration of the MmLec to speculate the antibiofilm properties of MmLec which was analyzed under Light Microscopy and Confocal Laser Scanning Microscopy. In addition, other functional characterization of MmLec showed the uniqueness of MmLec in agglutination of human erythrocyte as well as the cells of yeast Saccharomyces cerevisiae. Also, the phenoloxidase activity and encapsulation assay was evaluated. MTT assay displayed that MmLec are potent in anticancer activity. The study will help to understand the immunological interference and antimicrobial nature of MmLec which would be supportive in establishing a potential therapeutic tool and to develop better and novel disease control strategies in shrimp and farmed aquaculture industries as well as in health management.}, } @article {pmid31533077, year = {2020}, author = {Vijayakumar, K and Ramanathan, T}, title = {Musa acuminata and its bioactive metabolite 5-Hydroxymethylfurfural mitigates quorum sensing (las and rhl) mediated biofilm and virulence production of nosocomial pathogen Pseudomonas aeruginosa in vitro.}, journal = {Journal of ethnopharmacology}, volume = {246}, number = {}, pages = {112242}, doi = {10.1016/j.jep.2019.112242}, pmid = {31533077}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects ; Fruit/chemistry ; Furaldehyde/*analogs & derivatives/pharmacology ; Gene Expression Regulation, Bacterial ; Musa/*chemistry ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*pathogenicity ; Quorum Sensing ; Virulence ; }, abstract = {Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines.

AIM OF THE STUDY: To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa.

MATERIALS AND METHODS: The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml[-1] concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa.

RESULTS: MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml[-1] concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml[-1] concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa.

CONCLUSION: This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections.}, } @article {pmid31532581, year = {2019}, author = {She, P and Wang, Y and Liu, Y and Tan, F and Chen, L and Luo, Z and Wu, Y}, title = {Effects of exogenous glucose on Pseudomonas aeruginosa biofilm formation and antibiotic resistance.}, journal = {MicrobiologyOpen}, volume = {8}, number = {12}, pages = {e933}, pmid = {31532581}, issn = {2045-8827}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial/drug effects ; Glucose/*metabolism/pharmacology ; Humans ; Metabolic Networks and Pathways ; Metabolome ; Metabolomics/methods ; Microbial Sensitivity Tests ; Plasmids/genetics ; Pseudomonas aeruginosa/*drug effects/isolation & purification/*physiology ; }, abstract = {Pseudomonas aeruginosa is commonly found in nosocomial and life-threatening infections in patients. Biofilms formed by P. aeruginosa exhibit much greater resistance to antibiotics than the planktonic form of the bacteria. Few groups have studied the effects of glucose, a major carbon source, and metabolite, on P. aeruginosa biofilm formation and on its metabolic pathways. In this study, we investigated the effect of glucose on the biofilm formation ability of P. aeruginosa and carried out a metabolomic analysis to identify whether glucose alters the metabolic activity of P. aeruginosa in biofilms. We found that glucose efficiently promoted P. aeruginosa biofilm formation by upregulating the expression of the extracellular polysaccharide-related gene pslA. Treatment with glucose caused an increase in 7 metabolites (including 3-hydroxypropionic acid, glucose-6-phosphate, and 2,3-dimethylsuccinic acid) and a decrease in 18 metabolites (including myo-inositol, glutamine, and methoxamedrine) in the biofilm. In addition, there was a synergistic effect between glucose and horse serum on biofilm formation when the two were added in combination, which also increased the resistance of biofilm to levofloxacin therapy. Thus, our work sheds light on the underlying mechanisms by which glucose may enhance biofilm formation and identifies novel targets for developing strategies to counteract biofilm formation.}, } @article {pmid31532251, year = {2019}, author = {Wang, H and Palmer, J and Flint, S}, title = {Function of pYV Plasmid on Biofilm Formation of Yersinia enterocolitica ERL032123 in the Presence of Ca[2].}, journal = {Journal of food protection}, volume = {82}, number = {10}, pages = {1683-1687}, doi = {10.4315/0362-028X.JFP-19-018}, pmid = {31532251}, issn = {1944-9097}, mesh = {*Biofilms ; *Calcium/pharmacology ; *Plasmids/genetics ; Polycarboxylate Cement ; Virulence/genetics ; *Yersinia enterocolitica/drug effects/genetics/ultrastructure ; }, abstract = {The effect of the virulence plasmid pYV and calcium ions on biofilm of Yersinia enterocolitica biofilm formation was determined using a microtiter plate assay. Loss of the pYV plasmid prevented biofilm formation and the presence of Ca[2+] enhanced biofilm formation in cultures containing the pYV plasmid. Scanning electron microscopy supported the result from the microtiter plate assay showing that in the presence of Ca[2+], the wild-type Y. enterocolitica strain formed a strong biofilm on a polycarbonate surface. The results implied that Ca[2+] promotes Y. enterocolitica biofilm formation through the function of the pYV plasmid.}, } @article {pmid31531452, year = {2019}, author = {Baumeister, TUH and Staudinger, M and Wirgenings, M and Pohnert, G}, title = {Halogenated anilines as novel natural products from a marine biofilm forming microalga.}, journal = {Chemical communications (Cambridge, England)}, volume = {55}, number = {79}, pages = {11948-11951}, doi = {10.1039/c9cc05992j}, pmid = {31531452}, issn = {1364-548X}, mesh = {Aniline Compounds/*chemistry ; *Biofilms ; Biological Products/*chemistry ; Biosynthetic Pathways ; Halogenation ; Halogens/*chemistry ; Kinetics ; Microalgae/*chemistry ; }, abstract = {The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.}, } @article {pmid31531409, year = {2019}, author = {Hwang, G and Paula, AJ and Hunter, EE and Liu, Y and Babeer, A and Karabucak, B and Stebe, K and Kumar, V and Steager, E and Koo, H}, title = {Catalytic antimicrobial robots for biofilm eradication.}, journal = {Science robotics}, volume = {4}, number = {29}, pages = {}, pmid = {31531409}, issn = {2470-9476}, support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025848/DE/NIDCR NIH HHS/United States ; }, abstract = {Magnetically driven robots can perform complex functions in biological settings with minimal destruction. However, robots designed to damage deleterious biostructures could also have important impact. In particular, there is an urgent need for new strategies to eradicate bacterial biofilms as we approach a post-antibiotic era. Biofilms are intractable and firmly attached structures ubiquitously associated with drug-resistant infections and destruction of surfaces. Existing treatments are inadequate to both kill and remove bacteria leading to reinfection. Here we design catalytic antimicrobial robots (CARs) that precisely and controllably kill, degrade and remove biofilms with remarkable efficiency. CARs exploit iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality that (i) generate bactericidal free radicals, (ii) breakdown the biofilm exopolysaccharide (EPS) matrix, and (iii) remove the fragmented biofilm debris via magnetic field driven robotic assemblies. We develop two distinct CAR platforms. The first platform, the biohybrid CAR, is formed from NPs and biofilm degradation products. After catalytic bacterial killing and EPS disruption, magnetic field gradients assemble NPs and the biodegraded products into a plow-like superstructure. When driven with an external magnetic field, the biohybrid CAR completely removes biomass in a controlled manner, preventing biofilm regrowth. Biohybrid CARs can be swept over broad swathes of surface or can be moved over well-defined paths for localized removal with microscale precision. The second platform, the 3D molded CAR, is a polymeric soft robot with embedded catalytic-magnetic NPs, formed in a customized 3D printed mold to perform specific tasks in enclosed domains. Vane-shaped CARs remove biofilms from curved walls of cylindrical tubes, and helicoid-shaped CARs drill through biofilm clogs, while simultaneously killing bacteria. In addition, we demonstrate applications of CARs to target highly confined anatomical surfaces in the interior of human teeth. These 'kill-degrade-and-remove' CARs systems could have significant impact in fighting persistent biofilm-infections and in mitigating biofouling of medical devices and diverse surfaces.}, } @article {pmid31531109, year = {2019}, author = {Veloz, JJ and Alvear, M and Salazar, LA}, title = {Evaluation of Alternative Methods to Assess the Biological Properties of Propolis on Metabolic Activity and Biofilm Formation in Streptococcus mutans.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2019}, number = {}, pages = {1524195}, pmid = {31531109}, issn = {1741-427X}, abstract = {Several biological activities have been reported for the Chilean propolis, among their antimicrobial and antibiofilm properties, due to its high polyphenol content. In this study, we evaluate alternative methods to assess the effect of Chilean propolis on biofilm formation and metabolic activity of Streptococcus mutans (S. mutans), a major cariogenic agent in oral cavity. Biofilm formation was studied by using crystal violet and by confocal microscopy. The metabolic activity of biofilm was evaluated by MTT and by flow cytometry analysis. The results show that propolis reduces biofilm formation and biofilm metabolic activity in S. mutans. When the variability of the methods to measure biofilm formation was compared, the coefficient of variation (CV) fluctuated between 12.8 and 23.1% when using crystal violet methodology. On the other hand, the CV ranged between 2.2 and 3.3% with confocal microscopy analysis. The CV for biofilm's metabolic activity measured by MTT methodology ranged between 5.0 and 11.6%, in comparison with 1.9 to 3.2% when flow cytometry analysis was used. Besides, it is possible to conclude that the methods based on colored compounds presented lower precision to study the effect of propolis on biofilm properties. Therefore, we recommend the use of flow cytometry and confocal microscopy in S. mutans biofilm analysis.}, } @article {pmid31530887, year = {2019}, author = {Marbach, H and Mayer, K and Vogl, C and Lee, JYH and Monk, IR and Sordelli, DO and Buzzola, FR and Ehling-Schulz, M and Grunert, T}, title = {Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {13479}, pmid = {31530887}, issn = {2045-2322}, support = {P 29304/FWF_/Austrian Science Fund FWF/Austria ; }, mesh = {Adaptation, Biological ; Animals ; Bacterial Proteins ; *Biofilms/growth & development ; Cattle ; *Evolution, Molecular ; Female ; Hemolysis ; Host-Pathogen Interactions ; Mastitis, Bovine/*microbiology ; *Phenotype ; Proteolysis ; Sigma Factor/*deficiency ; Staphylococcal Infections/*veterinary ; Staphylococcus aureus/*genetics/growth & development/pathogenicity ; Virulence ; }, abstract = {Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.}, } @article {pmid31529027, year = {2019}, author = {Bjarnsholt, T and Jensen, PØ and Alhede, M}, title = {Revival of Krebs-Ringer balanced salt solution for the investigation of polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilm interaction.}, journal = {Pathogens and disease}, volume = {77}, number = {5}, pages = {}, doi = {10.1093/femspd/ftz052}, pmid = {31529027}, issn = {2049-632X}, mesh = {Biofilms/*growth & development ; Cells, Cultured ; Cytological Techniques ; *Host-Pathogen Interactions ; Humans ; Microbiological Techniques ; Neutrophils/*immunology/*microbiology ; Pseudomonas aeruginosa/*growth & development/*immunology ; Solutions/*chemistry ; }, abstract = {To study the interaction between aggregating bacteria and polymorphonuclear leukocytes (PMNs) in vitro, the chosen medium must favor both the isolated PMNs and the bacteria. To investigate the best-suited medium for the in vitro survival of isolated unactivated human PMNs, we compared three different mammalian cell media: Krebs-Ringer balanced salt solution (BSS), Hanks' BSS (HBSS) and Roswell Park Memorial Institute (RPMI) 1640. The death of PMNs was estimated by the release of lactate dehydrogenase activity. Furthermore, two types of serum, human (HS) and fetal bovine (FBS), were compared at different concentrations (0%, 2%, 5%, 10%) and at three different time points (2, 4, 20 h). We show that Krebs-Ringer BSS prolonged the survival of PMNs compared to HBSS and RPMI 1640 and that the addition of 10% FBS significantly enhanced the long-term survival (20 h) compared to HS. Furthermore, we observed aggregation of Pseudomonas aeruginosa when grown in the presence of either a mixture of histones, histone H3, arginine or lysine. In this study, we show that the use of Krebs-Ringer BSS is highly relevant for the study of the interaction of bacteria and PMNs in relation to novel treatment strategies of biofilm infections due to the reproduction of bacterial aggregation as seen in chronic bacterial infections.}, } @article {pmid31528252, year = {2019}, author = {Song, YG and Lee, SH}, title = {Efficacy of newly developed denture cleaning device on physical properties of denture material and Candida biofilm.}, journal = {Journal of dental sciences}, volume = {14}, number = {3}, pages = {248-254}, pmid = {31528252}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: Electrolyzed water has antimicrobial activity against oral microbes. The purpose of this study was to investigate the effects of a denture cleaning device that uses electrolyzed water on Candida biofilm on denture base-material and the physical properties of the denture material.

MATERIALS AND METHODS: Denture base-resin disks were prepared with Polymethyl methacrylate. After the formation of Candida albicans biofilm on the resin disks, the antimicrobial activity of the denture cleaning device and the chemical cleanser against C. albicans biofilm was compared. The resin disks were also treated with the cleaning device and the chemical cleanser for 150 days, and the physical properties were analyzed by an atomic force microscope, Vickers hardness tester, and colorimeter.

RESULTS: The denture cleaning device and the chemical cleanser reduced the levels of C. albicans biofilm on the denture resin. Upon immersing of the resin disks for 150 days, the electrolyzed water of the denture cleaning device did not significantly change the surface roughness of the specimens, but significantly reduced its Vickers hardness compared to the initial value. The color changes of the resin disk were 0.477 ± 0.076, 0.612 ± 0.095 and 0.562 ± 0.096 after treating with tap water, the chemical cleanser, and the denture cleaning device, respectively.

CONCLUSION: The denture cleaning device may be suitable for use by the elderly to clean dentures without side effects caused by the misuse of chemical cleanser.}, } @article {pmid31528123, year = {2019}, author = {Thieme, L and Hartung, A and Tramm, K and Klinger-Strobel, M and Jandt, KD and Makarewicz, O and Pletz, MW}, title = {MBEC Versus MBIC: the Lack of Differentiation between Biofilm Reducing and Inhibitory Effects as a Current Problem in Biofilm Methodology.}, journal = {Biological procedures online}, volume = {21}, number = {}, pages = {18}, pmid = {31528123}, issn = {1480-9222}, abstract = {BACKGROUND: Biofilms are communities of aggregated, matrix-embedded microbial cells showing a high tolerance to an in principle adequate antibiotic therapy, often resulting in treatment failure. A major challenge in the management of biofilm-associated infections is the development of adequate, standardized biofilm susceptibility testing assays that are clinically meaningful, i.e. that their results correlate with treatment outcome. Different biofilm susceptibility endpoint parameters like the minimal biofilm eradication concentration (MBEC) or the minimal biofilm inhibitory concentration (MBIC) have been suggested as a guide for treatment of biofilm-associated infections, however with inconsistent perception and use among biofilm researchers, leading to confusion and contradictions among different anti-biofilm component studies and clinical trials.

FINDINGS: Evaluation of anti-biofilm effects is mostly based on the untreated reference growth control biofilm measured at the same endpoint as the treated biofilm, neglecting the possible change of the untreated reference biofilm from the time point of pre-antimicrobial exposure to the measured endpoint. In this commentary, we point out the importance of individual quantification of mature, established biofilms before antimicrobial treatment for each biofilm model in order to draw conclusions on the measured biofilm effect size, i.e. biofilm reducing (MBEC) or biofilm inhibitory (MBIC) effects.

CONCLUSION: The assessment of pre-treatment biofilms contributes to a standardized use of biofilm susceptibility endpoint parameters, which is urgently needed to improve the clinical validity of future anti-biofilm assays.}, } @article {pmid31527127, year = {2019}, author = {Sultan, AR and Hoppenbrouwers, T and Lemmens-den Toom, NA and Snijders, SV and van Neck, JW and Verbon, A and de Maat, MPM and van Wamel, WJB}, title = {During the Early Stages of Staphylococcus aureus Biofilm Formation, Induced Neutrophil Extracellular Traps Are Degraded by Autologous Thermonuclease.}, journal = {Infection and immunity}, volume = {87}, number = {12}, pages = {}, pmid = {31527127}, issn = {1098-5522}, mesh = {Biofilms/*growth & development ; Extracellular Traps/*metabolism ; Fluorescence Resonance Energy Transfer ; Humans ; Microbial Viability ; Micrococcal Nuclease/*metabolism ; Neutrophils/*immunology ; Polysaccharides, Bacterial/metabolism ; Reactive Oxygen Species/metabolism ; Staphylococcal Infections/immunology/pathology ; Staphylococcus aureus/*growth & development/metabolism/*pathogenicity ; }, abstract = {Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization; on the contrary, host immune responses can be induced by bacterial eDNA. Previously, we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscove's modified Dulbecco's medium (IMDM) earlier than that of widely studied biofilms grown in tryptic soy broth (TSB). The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in biofilms grown in IMDM, minimal amounts of eDNA were found; instead, polysaccharide intercellular adhesin (PIA) was detected. To investigate if this early production of thermonuclease plays a role in immune modulation by biofilm, we studied the effect of thermonuclease on human neutrophil extracellular trap (NET) formation using a nuc knockout and complemented strain. We confirmed that thermonuclease produced by early-stage biofilms grown in IMDM degraded biofilm-induced NETs. Additionally, neither the presence of biofilms nor thermonuclease stimulated an increase in reactive oxygen species (ROS) production by neutrophils. Our findings indicated that S. aureus, during the early stages of biofilm formation, actively evades the host immune responses by producing thermonuclease.}, } @article {pmid31525949, year = {2019}, author = {Wang, ZH and Liu, JM and Li, CY and Wang, D and Lv, H and Lv, SW and Zhao, N and Ma, H and Wang, S}, title = {Bacterial Biofilm Bioinspired Persistent Luminescence Nanoparticles with Gut-Oriented Drug Delivery for Colorectal Cancer Imaging and Chemotherapy.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {40}, pages = {36409-36419}, doi = {10.1021/acsami.9b12853}, pmid = {31525949}, issn = {1944-8252}, mesh = {Animals ; *Biofilms/drug effects ; Cell Line ; Cell Line, Tumor ; Cell Survival/drug effects ; Colorectal Neoplasms/*diagnosis/*drug therapy ; *Diagnostic Imaging ; *Drug Delivery Systems ; Drug Liberation ; Fluorouracil/pharmacology/therapeutic use ; Gastrointestinal Tract/drug effects/*metabolism ; Humans ; *Luminescence ; Mice ; Nanoparticles/*chemistry/ultrastructure ; Silicon Dioxide/chemistry ; X-Ray Diffraction ; }, abstract = {Colorectal cancer (CRC) is now one of the leading causes of cancer incidence and mortality. Although nanomaterial-based drug delivery has been used for the treatment of colorectal cancer, inferior targeting ability of existing nanocarriers leads to inefficient treatment and side effects. Moreover, the majority of intravenously administered nanomaterials aggregate into the reticuloendothelial system, leaving a certain hidden risk to human health. All those problems gave great demands for further construction of well-performed and biocompatible nanomaterials for in vivo theranostics. In the present work, from a biomimetic point of view, Lactobacillus reuteri biofilm (LRM) was coated on the surface of trackable zinc gallogermanate (ZGGO) near-infrared persistent luminescence mesoporous silica to create the bacteria bioinspired nanoparticles (ZGGO@SiO2@LRM), which hold the inherent capability of withstanding the digestion of gastric acid and targeted release 5-FU to colorectum. Through the background-free persistent luminescence bioimaging of ZGGO, the coating of LRM facilitated the localization of ZGGO@SiO2@LRM to the tumor area of colorectum for more than 24 h after intragastric administration. Furthermore, ZGGO@SiO2@LRM hardly entered the blood, which avoided possible damage to immune organs such as the liver and spleen. In vivo chemotherapy experiment demonstrated the number of tumors per mouse in ZGGO@SiO2@LRM group decreased by one-half compared with the 5-FU group (P < 0.001). To sum up, this LRM bioinspired nanoparticles could tolerate the digestion of gastric acid, avoid aggregation by the immune system, favor gut-oriented drug delivery, and targeted release oral 5-FU into colorectum for more than 24 h, which may give new application prospects for targeted delivery of oral drugs into the colorectum.}, } @article {pmid31524581, year = {2019}, author = {Brown, JL and Johnston, W and Delaney, C and Short, B and Butcher, MC and Young, T and Butcher, J and Riggio, M and Culshaw, S and Ramage, G}, title = {Polymicrobial oral biofilm models: simplifying the complex.}, journal = {Journal of medical microbiology}, volume = {68}, number = {11}, pages = {1573-1584}, doi = {10.1099/jmm.0.001063}, pmid = {31524581}, issn = {1473-5644}, mesh = {Animals ; Bacteria/classification/genetics/*isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; Humans ; Mouth/*microbiology ; }, abstract = {Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. In vivo animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained in vitro offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.}, } @article {pmid31523511, year = {2019}, author = {Pelyuntha, W and Chaiyasut, C and Kantachote, D and Sirilun, S}, title = {Cell-free supernatants from cultures of lactic acid bacteria isolated from fermented grape as biocontrol against Salmonella Typhi and Salmonella Typhimurium virulence via autoinducer-2 and biofilm interference.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e7555}, pmid = {31523511}, issn = {2167-8359}, abstract = {BACKGROUND: Salmonella Typhi and Salmonella Typhimurium are the causative pathogens of salmonellosis, and they are mostly found in animal source foods (ASF). The inappropriate use of antibiotics enhances the possibility for the emergence of antibiotic resistance in pathogens and antibiotic residue in ASF. One promising alternative to antibiotics in animal farming is the use of lactic acid bacteria (LAB).

METHODS: The present study was carried out the cells and/or the cell-free culture supernatants (CFCS) from beneficial LAB against S. Typhi and S. Typhimurium. The antibacterial mechanisms of LAB-CFCS as biocontrol agents against both Salmonella serovars were investigated through the analysis of anti-salmonella growth activity, biofilm inhibition and quorum quenching activity.

RESULTS: Among 146 LAB strains isolated from 110 fermented food samples, the 2 strong inhibitory effect strains (WM33 and WM36) from fermented grapes against both Salmonella serovars were selected. Out of the selected strains, WM36 was the most effective inhibitor, which indicated S. Typhi by showing 95.68% biofilm inhibition at 20% biofilm inhibition concentration (BIC) and reduced 99.84% of AI-2 signaling interference. The WM33 was the best to control S. Typhimurium by producing 66.46% biofilm inhibition at only 15% BIC and 99.99% AI-2 signaling a reduction. The 16S rDNA was amplified by a polymerase chain reaction (PCR). The selected isolates were identified as Weissella viridescens WM33 and Weissella confusa WM36 based on nucleotide homology and phylogenetic analysis.

CONCLUSION: The metabolic extracts from Weissella spp. inhibit Salmonella serovars with the potential to be used as biocontrol agents to improve microbiological safety in the production of ASF.}, } @article {pmid31523409, year = {2019}, author = {Saidi, N and Owlia, P and Marashi, SMA and Saderi, H}, title = {Inhibitory effect of probiotic yeast Saccharomyces cerevisiae on biofilm formation and expression of α-hemolysin and enterotoxin A genes of Staphylococcus aureus.}, journal = {Iranian journal of microbiology}, volume = {11}, number = {3}, pages = {246-254}, pmid = {31523409}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus aureus, as an opportunistic pathogen, is the cause of a variety of diseases from mild skin infections to severe invasive infections and food poisoning. Increasing antibiotic resistance in S. aureus isolates has become a major threat to public health. The use of compounds produced by probiotics can be a solution to this problem. Thus, the purpose of this study was to investigate the effect of Saccharomyces cerevisiae on some virulence factors (biofilm, α-hemolysin, and enterotoxin A) of S. aureus.

MATERIALS AND METHODS: Supernatant and lysate extracts were prepared from S. cerevisiae S3 culture. Sub-MIC concentrations of both extracts were separately applied to S. aureus ATCC 29213 (methicillin-sensitive S. aureus; MSSA) and S. aureus ATCC 33591 (methicillin-resistant S. aureus; MRSA) strains. Biofilm formation of these strains was measured by microtiter plate assay and expression level of α-hemolysin and enterotoxin A genes (hla and sea, respectively) using real-time PCR technique.

RESULTS: The supernatant extract has reduced both biofilm formation and expression of sea and hla genes, while lysate extract had only anti-biofilm effects. The MRSA strain showed more susceptibility to yeast extracts than MSSA strain in all tests.

CONCLUSION: The present study exhibited favorable antagonistic effects of S. cerevisiae S3, as a probiotic yeast, on MSSA and MRSA strains. Based on the findings of this study, the compounds produced by this yeast can be used to control S. aureus infections; however, further similar studies should be conducted to confirm the findings of the present study.}, } @article {pmid31523169, year = {2019}, author = {Liu, J and Cai, M and Yan, H and Fu, J and Wu, G and Zhao, Z and Zhao, Y and Wang, Y and Sun, Y and You, Y and Lin, L and Huang, J and Huang, R and Zeng, J}, title = {Yunnan Baiyao reduces hospital-acquired pressure ulcers via suppressing virulence gene expression and biofilm formation of Staphylococcus aureus.}, journal = {International journal of medical sciences}, volume = {16}, number = {8}, pages = {1078-1088}, pmid = {31523169}, issn = {1449-1907}, mesh = {Aged ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Bacterial Toxins/genetics ; Biofilms/drug effects ; Drugs, Chinese Herbal/*pharmacology ; Female ; Gene Expression Regulation, Bacterial/drug effects ; Hemolysin Proteins/genetics ; Humans ; Iatrogenic Disease ; Male ; Middle Aged ; Pressure Ulcer/*drug therapy/microbiology ; Rabbits ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects/genetics/pathogenicity ; Trans-Activators/genetics ; Treatment Outcome ; Virulence/genetics ; }, abstract = {Yunnan Baiyao (YB) as a kind of famous Chinese herbal medicine, possessed hemostatic, invigorating the circulation of blood, and anti-inflammatory effects. Identifying strategies to protect patients at risk for hospital-acquired pressure ulcers (HAPU) is essential. Herein, our results showed that YB treatment can effectively reduce the acne wound area and improve efficacy in a comparative study of 60 cases HAPU patients with S. aureus positive of acne wound pathogens. Furthermore, YB inhibited HIa expression and suppressed accessory gene regulator (agr) system controlled by regulatory RNA II and RNA III molecule using pALC1740, pALC1742 and pALC1743 S. aureus strain linked to gfpuvr reporter gene. Moreover, YB downregulated cao mRNA expression and inhibited coagulase activity by RT-PCR, slide and tube coagulase test. Additionally, YB downregulated seb, sec, sed, and tsst-1 mRNA expression to suppress enterotoxin and tsst-1 secretion and adhesion function related genes sarA, icaA, and cidA mRNA expression. Taken together, the data suggest that YB may reduce HAPU via suppressing virulence gene expression and biofilm formation of S. aureus.}, } @article {pmid31521779, year = {2020}, author = {Alfa, MJ and Singh, H}, title = {Impact of wet storage and other factors on biofilm formation and contamination of patient-ready endoscopes: a narrative review.}, journal = {Gastrointestinal endoscopy}, volume = {91}, number = {2}, pages = {236-247}, doi = {10.1016/j.gie.2019.08.043}, pmid = {31521779}, issn = {1097-6779}, mesh = {*Biofilms ; Carrier State/prevention & control ; Cross Infection/*prevention & control ; Disinfection/*methods ; Endoscopes, Gastrointestinal/*microbiology ; Equipment Contamination/*prevention & control ; Humans ; }, abstract = {The 2019 U.S. Food and Drug Administration report indicates that the clinical studies undertaken by the 3 main GI endoscope manufacturers demonstrate 5.4% of patient-ready duodenoscopes remain culture positive for high-concern organisms. The root causes of this persistent contamination are poorly understood. The objectives of this review include summarizing (1) the impact of inadequate manual cleaning and inadequate drying during storage on the formation of build-up biofilm in endoscope channels, (2) the impact of defoaming agents used during patient procedures on drying efficacy, (3) the data showing the importance of build-up biofilm on persistent microbial survival, and (4) the potential impact of implementation of a quality systems approach in GI endoscopy reprocessing.}, } @article {pmid31521732, year = {2020}, author = {Horiuchi, A and Kokubu, E and Warita, T and Ishihara, K}, title = {Synergistic biofilm formation by Parvimonas micra and Fusobacterium nucleatum.}, journal = {Anaerobe}, volume = {62}, number = {}, pages = {102100}, doi = {10.1016/j.anaerobe.2019.102100}, pmid = {31521732}, issn = {1095-8274}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Firmicutes/*physiology ; Fusobacterium nucleatum/*physiology ; Symbiosis ; }, abstract = {Parvimonas micra is frequently isolated from lesions of apical periodontitis and is a major disease-related pathogen. One of the main causes of apical periodontitis is extraradicular biofilm. In this study, we investigated polymicrobial biofilm formation by P. micra and species associated with apical periodontitis. The coaggregation activity of P. micra with partner strains was investigated by visual assays. Synergistic biofilm formation was evaluated by cocultures of P. micra and partner strains. Growth of planktonic cells was measured by evaluating the absorbance at OD660, and biofilm formation was examined by staining with crystal violet. The effects of soluble components on synergistic biofilm formation and planktonic cell growth were examined after coculture of P. micra and other strains separated with a 0.4-μm pore-size porous membrane. P. micra coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, or Capnoctyophaga ochracea. P. micra showed no coaggregation with Staphylococcus aureus, S. epidermidis, or Prevotella intermedia. In mixed cultures, biofilm formation by P. micra and F. nucleatum was greater than that by P. micra and P. gingivalis or C. ochracea. In separated cocultures, planktonic cell growth of P. micra was enhanced by each of the three species. Biofilm formation by P. micra was enhanced by F. nucleatum or C. ochracea; however, no significant enhancement was observed with P. gingivalis. These data indicated that P. micra and F. nucleatum had synergistic effects in biofilm formation and that these effects may be important for colonization by these two species in apical periodontitis lesions.}, } @article {pmid31520957, year = {2019}, author = {Cheng, H and Cheng, D and Mao, J and Lu, T and Hong, PY}, title = {Identification and characterization of core sludge and biofilm microbiota in anaerobic membrane bioreactors.}, journal = {Environment international}, volume = {133}, number = {Pt A}, pages = {105165}, doi = {10.1016/j.envint.2019.105165}, pmid = {31520957}, issn = {1873-6750}, mesh = {Anaerobiosis ; Bacteria/classification ; *Biofilms ; Bioreactors/*microbiology ; Microbial Consortia ; *Microbiota ; Sewage/*microbiology ; Waste Disposal, Fluid ; }, abstract = {An analysis of sludge (i.e., 63 samples) and biofilm (i.e., 79 samples) sampled from 13 anaerobic membrane bioreactors (AnMBR) was conducted. Predominant microbial community identification and multivariate analysis indicate that these reactors showed different microbial community structure, but these differences had no impact on the overall AnMBR performance. Instead, core microbial genera which occurred in ≥90% of sludge (20 genera) and biofilm (12 genera) samples could potentially account for the AnMBR performance. A further calculation on net growth rate (NGR) of core genera in sludge suggested distribution into two main groups (i.e., I: low relative abundance and NGR, II: high relative abundance or high NGR). Consistent positive correlations between bacterial genera were observed among those that exhibited either high relative abundance or high NGR. The anaerobic microbial consortium in both sludge and biofilm were largely affected by stochastic dispersal and migration processes (i.e., neutral assembly). However, Acinetobacter spp. and Methanobacterium spp. occurred consistently in higher frequency in the biofilm but in lower occurrence frequency in the AnMBR permeate. Findings from this study suggest first, specific core microorganisms exist in the sludge regardless of the operating conditions of the AnMBRs, and second, prevention of biofoulant layer on anaerobic membranes can be devised by minimizing attachment of microbes on surfaces in a non-selective manner.}, } @article {pmid31520885, year = {2019}, author = {Yuan, Z and Tao, B and He, Y and Mu, C and Liu, G and Zhang, J and Liao, Q and Liu, P and Cai, K}, title = {Remote eradication of biofilm on titanium implant via near-infrared light triggered photothermal/photodynamic therapy strategy.}, journal = {Biomaterials}, volume = {223}, number = {}, pages = {119479}, doi = {10.1016/j.biomaterials.2019.119479}, pmid = {31520885}, issn = {1878-5905}, mesh = {Alkaline Phosphatase/metabolism ; Animals ; Anti-Bacterial Agents/pharmacology ; Biocompatible Materials ; *Biofilms ; Bone Substitutes ; Cell Differentiation ; Diazonium Compounds/chemistry ; Indocyanine Green/pharmacology ; Indoles ; Light ; Male ; Metal Nanoparticles/chemistry ; Orthopedics ; Osseointegration ; Osteogenesis ; Photochemotherapy/*methods ; Photosensitizing Agents/pharmacology ; Phototherapy/*methods ; Polymers ; Prosthesis Design ; Pyridines/chemistry ; Rats ; Rats, Sprague-Dawley ; Spectroscopy, Near-Infrared ; Staphylococcus aureus/metabolism ; Titanium/*chemistry ; }, abstract = {Biofilm formation is a main challenge in treatment of bone-implant-associated infections, resulting in tolerance to immune system and antibiotics. However, smart non-surgical or non-invasive treatment methods of combating established biofilm on an implant have been less reported. Herein, a therapeutic system consisting of mesoporous polydopamine nanoparticles (MPDA) to combat biofilm is reported for the first time. We develop a synergistic photothermal/photodynamic therapy (PTT/PDT) strategy aiming for biofilms eradication on titanium (Ti) implant, which is integrated with MPDA loading with photosensitizer Indocyanine Green (ICG) by π-π stacking. Specifically, MPDA is functionalized with RGD peptide to endow the modified Ti sample (Ti-M/I/RGD) with good cytocompatibility. More importantly, Ti-M/I/RGD implant remarkably kills Staphylococcus aureus (S. aureus) biofilm with an efficiency of 95.4% in vivo upon near infrared (NIR). After biofilm eradication, implant still displays great performance regarding osteogenesis and osseointegration. Overall, this study provides a PTT/PDT strtategy for the development of antibacterial Ti implants for potential orthpediac application.}, } @article {pmid31519064, year = {2019}, author = {Widiasih Widiyanto, T and Chen, X and Iwatani, S and Chibana, H and Kajiwara, S}, title = {Role of major facilitator superfamily transporter Qdr2p in biofilm formation by Candida glabrata.}, journal = {Mycoses}, volume = {62}, number = {12}, pages = {1154-1163}, doi = {10.1111/myc.13005}, pmid = {31519064}, issn = {1439-0507}, mesh = {Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Candida glabrata/*genetics/*physiology ; Drug Resistance, Fungal/genetics ; Fluconazole/pharmacology ; Fungal Proteins/*genetics/metabolism ; Membrane Transport Proteins/*genetics/metabolism ; Microbial Sensitivity Tests ; Mutation ; }, abstract = {Candida glabrata represents the second-most frequent cause of candidiasis infections of the mucosa, bloodstream and genito-urinary tract in immunocompromised individuals. The incidence of C glabrata infection has increased significantly in the last two decades, mainly due to this species' abilities to resist various antifungal drugs and to form biofilms. We focused on the relationship between biofilm formation and the product of QDR2, a C glabrata member of the major facilitator superfamily (MFS) gene family, given that fungal biofilm formation limits drug penetration and is associated with persistent infection. The fungal cells in biofilms were compared between a C glabrata ∆qdr2 mutant and its wild-type strain. Cells were analysed for metabolism activity and drug susceptibility (using tetrazolium assay), adhesion activity, growth assay and intracellular pH (using flow cytometry). Compared to the wild type, the C glabrata ∆qdr2 showed lower adhesion activity and higher fluconazole susceptibility when assessed as a biofilm. The mutant also showed decreased metabolic activity during biofilm formation. Furthermore, the mutant grew more slowly under neutral-basic pH conditions. The qdr2 deletion in C glabrata resulted in an impaired ability to maintain pH homeostasis, which led in turn to a reduction of cell growth and of adherence to an artificial matrix. These results suggested that the Qdr2p function is needed for proper biofilm formation and biofilm maintenance in C glabrata as well as biofilm drug resistance towards fluconazole. Qdr2p may play an important role in C glabrata's ability to form biofilms on implanted medical devices in human bodies.}, } @article {pmid31518800, year = {2019}, author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Pirozzi, F and Esposito, G}, title = {Effect of carbon-to-nitrogen ratio on simultaneous nitrification denitrification and phosphorus removal in a microaerobic moving bed biofilm reactor.}, journal = {Journal of environmental management}, volume = {250}, number = {}, pages = {109518}, doi = {10.1016/j.jenvman.2019.109518}, pmid = {31518800}, issn = {1095-8630}, mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; *Nitrification ; Nitrogen ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {In this study, long-term simultaneous nitrification denitrification (SND) and phosphorous removal were investigated in a continuous-flow microaerobic MBBR (mMBBR) operated at a dissolved oxygen (DO) concentration of 1.0 (±0.2) mg L[-1]. The mMBBR performance was evaluated at different feed carbon-to-nitrogen (C/N) ratios (2.7, 4.2 and 5.6) and HRTs (2 days and 1 day). Stable long-term mMBBR operation and chemical oxygen demand (COD), total inorganic nitrogen (TIN) and phosphorous (P-PO4[3-]) removal efficiencies up to 100%, 68% and 72%, respectively, were observed at a feed C/N ratio of 4.2. Lower TIN removal efficiency and unstable performance were observed at feed C/N ratios of 2.7 and 5.6, respectively. HRT decrease from 2 days to 1 day resulted in transient NH4[+] accumulation and higher NO2[-]/NO3[-] ratio in the effluent. Batch activity tests showed that biofilm cultivation at a feed C/N ratio of 4.2 resulted in the highest denitrifying activity (189 mg N gVSS[-1] d[-1]), whereas the highest nitrifying activity (316 mg N gVSS[-1] d[-1]) was observed after cultivation at a feed C/N ratio of 2.7. Thermodynamic modeling with Visual MINTEQ and stoichiometric evaluations revealed that P removal was mainly biological and can be attributed to the P-accumulating capacity of denitrifying bacteria.}, } @article {pmid31518447, year = {2019}, author = {Kettles, RA and Tschowri, N and Lyons, KJ and Sharma, P and Hengge, R and Webber, MA and Grainger, DC}, title = {The Escherichia coli MarA protein regulates the ycgZ-ymgABC operon to inhibit biofilm formation.}, journal = {Molecular microbiology}, volume = {112}, number = {5}, pages = {1609-1625}, pmid = {31518447}, issn = {1365-2958}, support = {BB/N014200/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012504/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; DNA-Binding Proteins/genetics/*metabolism ; DNA-Directed RNA Polymerases/genetics ; Drug Resistance, Multiple, Bacterial/genetics ; Escherichia coli/genetics/*growth & development ; Escherichia coli Proteins/genetics/*metabolism ; Multienzyme Complexes/genetics/*metabolism ; Phosphoprotein Phosphatases/genetics/*metabolism ; Porins/genetics/*metabolism ; Protein Kinases/genetics/*metabolism ; Sigma Factor/genetics ; Transcription, Genetic/genetics ; }, abstract = {The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work, we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ-ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ-ymgABC promoter is recognised by σ[38] (RpoS)-associated RNA polymerase (RNAP). Surprisingly, MarA does not influence σ[38] -dependent transcription. Instead, MarA drives transcription by the housekeeping σ[70] -associated RNAP. The effects of MarA on ycgZ-ymgABC expression are coupled with biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.}, } @article {pmid31516325, year = {2019}, author = {Farrag, HA and Hosny, AEMS and Hawas, AM and Hagras, SAA and Helmy, OM}, title = {Potential efficacy of garlic lock therapy in combating biofilm and catheter-associated infections; experimental studies on an animal model with focus on toxicological aspects.}, journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society}, volume = {27}, number = {6}, pages = {830-840}, pmid = {31516325}, issn = {1319-0164}, abstract = {BACKGROUND: Life-threatening central venous catheter-related infections are primarily initiated by biofilm formation on the catheter surface. Antibiotic lock therapy is recommended for eradicating intraluminal biofilm. In the era of antibiotic resistance, antibiotics of natural origins provide an effective and cheap option for combating resistant strains. Garlic especially stole the spotlight because of its impressive antimicrobial effectiveness against such superbugs.

AIM: Is to estimate the potential use of fresh garlic extract (FGE) as a lock agent against multi-drug resistant (MDR) bacteria.

METHODS: The agar well diffusion and broth microdilution techniques were employed to test the antimicrobial activities of FGE against five MDR strains; E. coli, Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Serratia marscens (S. marscens) and Methicillin-resistant Staphylococcus aureus (MRSA). Then the protective and therapeutic efficiencies of FGE against bacterial biofilms were in-vitro evaluated; at concentrations of 100, 75, 50 and 25%; in tissue culture plate (TCP) and on the polyurethane (PU) sheets using the crystal violet (CV) assay and colony-forming unit (CFU), respectively. Scanning electron microscopy (SEM) was also used to confirm eradication of biofilms on PU sheets. Finally, systemic and deep tissue infections by P. aeruginosa and MRSA were induced in mice that were then treated by FGE at either 100 or 200 mg/kg for seven days. Where the antibacterial activity was assessed by tissue and blood culturing at the end of the treatment period. Biochemical, hematological and histological parameters were also investigated.

RESULTS: FGE exhibited potent in-vitro and in-vivo antibacterial and antibiofilm activities against MDR strains. It not only didn't exhibit toxicological effects at the hematological and the histological levels but also provided protective effects as demonstrated by the significant drop in the biochemical parameters.

CONCLUSION: FGE has the potential to be used as a prophylactic and/or therapeutic lock agent against biofilm-associated infections caused by MDR bacteria.}, } @article {pmid31515192, year = {2020}, author = {Kim, A and Jung, JH and Lee, YJ and Park, JW and Pyon, JK}, title = {Minimally invasive salvage of infected breast tissue expanders: A continuous closed irrigation technique based on surface biofilm disruption.}, journal = {Journal of plastic, reconstructive & aesthetic surgery : JPRAS}, volume = {73}, number = {2}, pages = {295-302}, doi = {10.1016/j.bjps.2019.07.020}, pmid = {31515192}, issn = {1878-0539}, mesh = {*Biofilms ; Case-Control Studies ; Female ; Humans ; Mammaplasty/*methods ; Middle Aged ; Minimally Invasive Surgical Procedures ; Prosthesis-Related Infections/*etiology/*surgery ; Retrospective Studies ; Salvage Therapy/*methods ; *Therapeutic Irrigation ; Tissue Expansion Devices/*adverse effects ; }, abstract = {BACKGROUND: Removal of the infected device has been the general treatment for device-associated infection in antibiotic failure. There have been anecdotal attempts to salvage infected medical devices by introducing a continuous closed irrigation system.

OBJECTIVE: This study examines whether continuous closed irrigation of an infected device is a successful alternative to removal in patients with recalcitrant device-associated infection.

METHODS: Patients who were diagnosed with recalcitrant periexpander infections during the course of expander-implant breast reconstruction from 2010 to 2018 were enrolled in a retrospective case-control study. Patients who failed antibiotics before 2017 underwent expander removal, but patients since 2017 underwent continuous closed irrigation of the infected expanders. Treatment details and clinical outcomes were compared. Rationale for expander irrigation was based on review of the current literature on biofilm research.

RESULTS: During the study period, 21 out of the 1176 patients were diagnosed with periexpander infection recalcitrant to antibiotic therapy. Among the 21 patients, 16 underwent expander removal and five underwent expander irrigation. Clinical outcomes were comparable in terms of resolution of infection signs. The irrigation group showed fewer patients who abandoned reconstruction after infection treatment (removal = 11/16, irrigation = 1/5). Literature review revealed that expander irrigation might have induced hydrodynamic disruption of the biofilm structure.

CONCLUSION: Expander irrigation was less invasive than removal and effective in suppressing severe recalcitrant periexpander infection. Continuous closed irrigation of infected expander devices may be a successful antibiofilm strategy in treating device-associated infections in select patients.}, } @article {pmid31514534, year = {2019}, author = {Braga, AS and Girotti, LD and de Melo Simas, LL and Pires, JG and Pelá, VT and Buzalaf, MAR and Magalhães, AC}, title = {Effect of commercial herbal toothpastes and mouth rinses on the prevention of enamel demineralization using a microcosm biofilm model.}, journal = {Biofouling}, volume = {35}, number = {7}, pages = {796-804}, doi = {10.1080/08927014.2019.1662897}, pmid = {31514534}, issn = {1029-2454}, mesh = {Animals ; Biofilms/*drug effects ; Cattle ; Chlorhexidine/pharmacology ; Dental Enamel/*drug effects ; Mouthwashes/*pharmacology ; Sodium Fluoride ; Tooth Demineralization/*prevention & control ; *Toothpastes ; }, abstract = {This work evaluated the effects of commercial toothpastes and mouth rinses containing natural/herbal agents on biofilm viability, extracellular polysaccharide (EPS) production and on enamel demineralization in vitro. Microcosm biofilm was produced on bovine enamel for 5 days and treated daily with: Orgânico natural[®] (toothpaste/mouth rinse), Boni Natural Menta & Malaleuca[®] (toothpaste/mouth rinse), Propolis & Myrrh[®] (toothpaste), Colgate Total 12 Clean Mint[®] (toothpaste, positive control), Malvatricin[®] Plus (mouth rinse), PerioGard[®] (mouth rinse, positive control) or PBS (negative control). Tom's Propolis & Myrrh[®] and Colgate Total 12[®] toothpastes and Malvatricin[®] Plus and PerioGard[®] mouth rinses significantly reduced biofilm viability (p < 0.05). Only PerioGard[®] had significant effects on biofilm thickness and EPS. Despite the indication that Tom's Propolis & Myrrh[®] significantly reduced lesion depth, only Colgate Total 12[®] significantly reduced mineral loss. Malvatricin[®] Plus significantly reduced mineral loss and lesion depth, as did PerioGard[®]. Some herbal products, Malvatricin[®] Plus and Tom's Propolis & Myrrh[®], showed anticaries effects.}, } @article {pmid31514307, year = {2019}, author = {Balázs, VL and Horváth, B and Kerekes, E and Ács, K and Kocsis, B and Varga, A and Böszörményi, A and Nagy, DU and Krisch, J and Széchenyi, A and Horváth, G}, title = {Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {18}, pages = {}, pmid = {31514307}, issn = {1420-3049}, support = {NKFI 18 K 128217//NKFI (National Research, Development and Innovation Office)/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chromatography, Thin Layer/*methods ; Emulsions/chemistry ; Haemophilus/*drug effects/*physiology ; Microbial Sensitivity Tests ; Nanoparticles/chemistry ; Oils, Volatile/*pharmacology ; Volatile Organic Compounds/analysis ; }, abstract = {Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.}, } @article {pmid31514119, year = {2019}, author = {Zhang, Q and Yu, Z and Jin, S and Zhu, L and Liu, C and Zheng, H and Zhou, T and Liu, Y and Ruan, R}, title = {Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition.}, journal = {Bioresource technology}, volume = {293}, number = {}, pages = {122091}, doi = {10.1016/j.biortech.2019.122091}, pmid = {31514119}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; *Chlorella vulgaris ; Lignin ; }, abstract = {Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher and hydrophilic bio-carrier could yield more algal biomass than smoother and hydrophobic bio-carrier. Pine sawdust (diameter: 0.420-0.595 mm) performed the best when cultured Diplosphaera sp. (9.61 g·m[-2]·day[-1]) biofilm. Meanwhile, bio-carriers could be leached by the culture medium during cultivation, and their energy conversion proprieties could be improved due to the reduced ash contents and the decreased crystallinities. In addition, Chlorella vulgaris growth tests indicated that pine sawdust (15.45%) leachate promoted cell growth, whereas rick husk (15.48%) and sugarcane bagasse (13.19%) leachate inhibited cell growth. And bio-carriers leachates also modified the chemical compositions (lipid, protein and carbohydrate) of algal cells and increased the corresponding saturated fatty acids methyl ester content (from 48.71 to 55.58-57.08%).}, } @article {pmid31514099, year = {2019}, author = {Wang, G and Liu, Y and Wu, M and Zong, W and Yi, X and Zhan, J and Liu, L and Zhou, H}, title = {Coupling the phenolic oxidation capacities of a bacterial consortium and in situ-generated manganese oxides in a moving bed biofilm reactor (MBBR).}, journal = {Water research}, volume = {166}, number = {}, pages = {115047}, doi = {10.1016/j.watres.2019.115047}, pmid = {31514099}, issn = {1879-2448}, mesh = {Bacteria ; *Biofilms ; *Bioreactors ; Manganese Compounds ; Oxidation-Reduction ; Oxides ; RNA, Ribosomal, 16S ; Waste Disposal, Fluid ; }, abstract = {Phenolic wastewater containing phenol and 4-chlorophenol pose a risk to the environment and to human health. Treating them using chemical-biological coupling method is challenging. In this study, manganese oxidizing bacteria (MnOB) were enriched in moving bed biofilm reactor (MBBR) using synthetic phenol wastewater (800 mg L[-1]) to facilitate in situ production of biogenic manganese oxides (BioMnOx) after 90 days of operation. Then, 4-chlorophenol (4-CP) was added to the MBBR to simulate mixed phenolic wastewater. Comparing the MBBR (R1) without feeding Mn(II) and the MBBR with BioMnOx (R2) production, R2 exhibited robust phenol and 4-CP removal performance. 16S rRNA gene sequencing was employed to determine the microbial community. Subsequently, a batch experiment demonstrated that partly purified BioMnOx does not exhibits a capacity for phenol removal, but can efficiently remove 4-CP. Interestingly, 5-chloro-2-hydroxymuconic semialdehyde was found in the products of 4-CP degradation, which was the unique product of 4-CP degradation by catechol 2,3-dioxygenase (C23O). In both reactors, only catechol 1,2-dioxygenase (C12O) activity from microbes can be detected, indicating that the existence of BioMnOx provide an alternative pathway in addition to microbe driven 4-CP degradation. Overall, MBBR based MnOB enrichment under high phenol concentration was achieved, and 4-CP/phenol removal can be accelerated by in situ-formed BioMnOx. Considering the C23O-like activity of BioMnOx, our results suggest a new coupling strategy that involves nanomaterials and a microbial consortium.}, } @article {pmid31513898, year = {2019}, author = {Thiruvengadam, M and Venkidasamy, B and Karuppasamy, P and Muthusamy, R and Nile, SH and Subramanian, U}, title = {'Biofilm Clippers'- enzyme formulation for bovine mastitic biofilm therapy.}, journal = {Microbial pathogenesis}, volume = {137}, number = {}, pages = {103740}, doi = {10.1016/j.micpath.2019.103740}, pmid = {31513898}, issn = {1096-1208}, mesh = {Amylases/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cattle ; Cellulases/pharmacology ; Esterases/pharmacology ; Extracellular Polymeric Substance Matrix/*drug effects ; Female ; Mammary Glands, Animal ; Mannosidases/pharmacology ; Mastitis, Bovine/*drug therapy/microbiology ; Staphylococcal Infections/drug therapy/microbiology/veterinary ; Staphylococcus aureus/drug effects/isolation & purification ; }, abstract = {Mastitis is one of the most important diseases that are threatening modern dairy farms. Biofilms of mastitic teat canal have serious clinical implications because of colonized pathogens having the ability to construct an extracellular polymeric substance (EPS) with increased tolerance to antimicrobials leads to difficulty in eradicating the infection. In this study, we investigated the synergistic biofilm disruptive effect of a combination of carbohydrate hydrolases targeting extracellular polysaccharides of biofilm matrix and we termed it as 'Biofilm Clippers (BC)'. Our findings demonstrate that the BC formulation exhibits intense biofilm-disrupting activity against Staphylococcus aureus biofilms. The results of the study showed that BC enables activity equivalent to physiologically achievable concentrations in disrupting biofilms of S. aureus in vitro. The synergistic anti-biofilm activities of BC on S. aureus biofilms demonstrated that the biofilm matrix is predominant of complex polysaccharides. Further, the confocal microscopic analysis demonstrates that the BC formulation is highly effective compared to the single treatment of either of the enzymes in disrupting the biofilm. To the best of our knowledge, this is the first report on the synergistic anti-biofilm activity of a class of enzyme formulation against mastitic biofilm mass. Even though a small study showed a promising effect on mastitic teat canal, further extensive investigation on a large number of bovines for mastitis therapeutic potential of this BC-derived product is now warranted.}, } @article {pmid31513491, year = {2019}, author = {Roes, C and Calladine, L and Morris, C}, title = {Biofilm management using monofilament fibre debridement technology: outcomes and clinician and patient satisfaction.}, journal = {Journal of wound care}, volume = {28}, number = {9}, pages = {608-622}, doi = {10.12968/jowc.2019.28.9.608}, pmid = {31513491}, issn = {0969-0700}, mesh = {Anti-Infective Agents/*therapeutic use ; *Biofilms ; *Clinical Competence ; Debridement/*methods ; Disease Management ; Health Personnel ; Humans ; *Patient Satisfaction ; Wound Infection/*therapy ; }, abstract = {OBJECTIVE: Best practice in wound bed preparation and biofilm-based wound management includes debridement to create a clean wound bed and to assist in minimising the redevelopment of biofilm. Biofilm that is not removed inhibits healing and redevelops if not prevented from doing so with topical antimicrobial agents. Monofilament fibre debriding technology (MFDT) is used for effective and rapid mechanical debridement of loose material, slough and biofilm. The objective of this evaluation was to determine the clinical effect and consequential levels of health professional and patient satisfaction with the results of a biofilm pathway that included MFDT to achieve debridement.

METHODS: This non-comparative, open label evaluation was conducted in static and non-static wounds that required debridement. MFDT was used to debride in a two-week evaluation of a biofilm pathway. Wounds were debrided three times in week one and twice in week two. Each debridement was followed by treatment with an antimicrobial dressing. Other care included secondary dressings and compression delivered according to local practice, guidelines and formularies. After the clinical evaluation, health professionals were invited to complete an online survey of the clinical outcomes and their satisfaction with the biofilm pathway.

RESULTS: There were 706 health professionals who provided answers to the survey questions. Wound types evaluated were leg ulcers (67.4%), pressure ulcers (10%), dehisced surgical wounds (1.7%), diabetic foot ulcers (7.4%) and other wounds (13.4%). Of the wounds, 9% were reported as non-static despite the eligibility criteria. Not all wounds followed the pathway. The most frequently-used antimicrobial was silver. Non-antimicrobial products used included all-in-one dressings, other secondary dressings and compression. There was a change in 77% of wounds overall after two weeks. Change was reported almost equally for both static and non-static wounds. Health professionals who did or did not follow the pathway were 'completely satisfied' or 'satisfied' with the overall clinical outcome 96% and 95%, respectively. Of the patients, 77% were 'completely satisfied' or 'satisfied' with healing after following the pathway, as reported by the treating health professional.

CONCLUSION: The biofilm pathway that includes MFDT appears effective. Wounds managed on the pathway were debrided effectively and healing progressed to the satisfaction of both health professionals and patients.}, } @article {pmid31512521, year = {2019}, author = {Jiang, X and Yan, X and Gu, S and Yang, Y and Zhao, L and He, X and Chen, H and Ge, J and Liu, D}, title = {Biosurfactants of Lactobacillus helveticus for biodiversity inhibit the biofilm formation of Staphylococcus aureus and cell invasion.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {1133-1146}, doi = {10.2217/fmb-2018-0354}, pmid = {31512521}, issn = {1746-0921}, mesh = {Animals ; Anti-Bacterial Agents/metabolism/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Cells, Cultured ; Endocytosis/*drug effects ; Humans ; Keratinocytes/microbiology ; Lactobacillus helveticus/*metabolism ; Staphylococcus aureus/*drug effects/growth & development ; Surface-Active Agents/metabolism/*pharmacology ; }, abstract = {Aim: This study aimed to evaluate the differences of biosurfactants produced by two Lactobacillus helveticus strains against the biofilm formation of Staphylococcus aureus in vitro and in vivo. Materials & methods: Scanning electron microscopy, Real time-quantitative PCR (RT-qPCR) and cell assay were used to analyze the inhibiting effect of biosurfactants against biofilm formation. Results & conclusion: Results showed that the biosurfactants have anti-adhesive and inhibiting effects on biofilm formation in vivo and in vitro. The biofilm-formative genes and autoinducer-2 signaling regulated these characteristics, and the biosurfactant L. helveticus 27170 is better than that of 27058. Host cell adhesion and invasion results indicated that the biosurfactants L. helveticus prevented the S. aureus invading the host cell, which may be a new strategy to eliminate biofilms.}, } @article {pmid31511592, year = {2019}, author = {Lu, H and Que, Y and Wu, X and Guan, T and Guo, H}, title = {Metabolomics Deciphered Metabolic Reprogramming Required for Biofilm Formation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {13160}, pmid = {31511592}, issn = {2045-2322}, mesh = {Amino Acids/metabolism ; Biofilms/*growth & development ; Carbohydrate Metabolism ; Glycolipids/metabolism ; Mass Spectrometry ; *Metabolic Networks and Pathways ; *Metabolome ; Metabolomics/*methods ; Plankton/classification/*physiology ; }, abstract = {Biofilm formation plays a key role in many bacteria causing infections, which mostly accounts for high-frequency infectious recurrence and antibiotics resistance. In this study, we sought to compare modified metabolism of biofilm and planktonic populations with UTI89, a predominant agent of urinary tract infection, by combining mass spectrometry based untargeted and targeted metabolomics methods, as well as cytological visualization, which enable us to identify the driven metabolites and associated metabolic pathways underlying biofilm formation. Surprisingly, our finding revealed distinct differences in both phenotypic morphology and metabolism between two patterns. Furthermore, we identified and characterized 38 differential metabolites and associated three metabolic pathways involving glycerolipid metabolism, amino acid metabolism and carbohydrate metabolism that were altered mostly during biofilm formation. This discovery in metabolic phenotyping permitted biofilm formation shall provide us a novel insight into the dissociation of biofilm, which enable to develop novel biofilm based treatments against pathogen causing infections, with lower antibiotic resistance.}, } @article {pmid31510757, year = {2020}, author = {Papadopoulou, D and Dabrowska, A and Harries, PG and Webb, JS and Allan, RN and Salib, RJ}, title = {Evaluation of a Bioengineered Honey and Its Synthetic Equivalent as Novel Staphylococcus aureus Biofilm-Targeted Topical Therapies in Chronic Rhinosinusitis.}, journal = {American journal of rhinology & allergy}, volume = {34}, number = {1}, pages = {80-86}, doi = {10.1177/1945892419874700}, pmid = {31510757}, issn = {1945-8932}, mesh = {Bioengineering/*methods ; Biofilms/*drug effects ; Chronic Disease ; *Honey ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development ; Microscopy, Confocal ; Rhinitis/diagnosis/microbiology/*therapy ; Sinusitis/diagnosis/microbiology/*therapy ; Staphylococcal Infections/diagnosis/microbiology/*therapy ; }, } @article {pmid31508379, year = {2019}, author = {Miao, X and Liu, H and Zheng, Y and Guo, D and Shi, C and Xu, Y and Xia, X}, title = {Inhibitory Effect of Thymoquinone on Listeria monocytogenes ATCC 19115 Biofilm Formation and Virulence Attributes Critical for Human Infection.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {304}, pmid = {31508379}, issn = {2235-2988}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics ; Bacterial Toxins/metabolism ; Benzoquinones/*antagonists & inhibitors ; Biofilms/*drug effects/growth & development ; Biomass ; Genes, Bacterial/genetics ; Heat-Shock Proteins/metabolism ; Hemolysin Proteins/genetics/metabolism ; Humans ; Listeria monocytogenes/*drug effects/genetics/metabolism ; Listeriosis/microbiology ; Microbial Sensitivity Tests ; Real-Time Polymerase Chain Reaction ; Virulence/drug effects/genetics ; }, abstract = {This study aimed to determine the antimicrobial activity of thymoquinone (TQ) against Listeria monocytogenes, and to examine its inhibitory effects on biofilm formation, motility, hemolysin production, and attachment-invasion of host cells. The minimum inhibitory concentrations (MICs) of TQ against eight different L. monocytogenes strains ranged from 6.25-12.50 μg/mL. Crystal violet staining showed that TQ clearly reduced biofilm biomass at sub-MICs in a dose-dependent manner. Scanning electron microscopy suggested that TQ inhibited biofilm formation on glass slides and induced an apparent collapse of biofilm architecture. At sub-MICs, TQ effectively inhibited the motility of L. monocytogenes ATCC 19115, and significantly impacted adhesion to and invasion of human colon adenocarcinoma cells as well as the secretion of listeriolysin O. Supporting these findings, real-time quantitative polymerase chain reaction analysis revealed that TQ down-regulated the transcription of genes associated with motility, biofilm formation, hemolysin secretion, and attachment-invasion in host cells. Overall, these findings confirm that TQ has the potential to be used to combat L. monocytogenes infection.}, } @article {pmid31508278, year = {2019}, author = {Li, M and Li, L and Su, K and Liu, X and Zhang, T and Liang, Y and Jing, D and Yang, X and Zheng, D and Cui, Z and Li, Z and Zhu, S and Yeung, KWK and Zheng, Y and Wang, X and Wu, S}, title = {Highly Effective and Noninvasive Near-Infrared Eradication of a Staphylococcus aureus Biofilm on Implants by a Photoresponsive Coating within 20 Min.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {6}, number = {17}, pages = {1900599}, pmid = {31508278}, issn = {2198-3844}, abstract = {Biofilms have been related to the persistence of infections on medical implants, and these cannot be eradicated because of the resistance of biofilm structures. Therefore, a biocompatible phototherapeutic system is developed composed of MoS2, IR780 photosensitizer, and arginine-glycine-aspartic acid-cysteine (RGDC) to safely eradicate biofilms on titanium implants within 20 min. The magnetron-sputtered MoS2 film possesses excellent photothermal properties, and IR780 can produce reactive oxygen species (ROS) with the irradiation of near-infrared (NIR, λ = 700-1100 nm) light. Consequently, the combination of photothermal therapy (PTT) and photodynamic therapy (PDT), assisted by glutathione oxidation accelerated by NIR light, can provide synergistic and rapid killing of bacteria, i.e., 98.99 ± 0.42% eradication ratio against a Staphylococcus aureus biofilm in vivo within 20 min, which is much greater than that of PTT or PDT alone. With the assistance of ROS, the permeability of damaged bacterial membranes increases, and the damaged bacterial membranes become more sensitive to heat, thus accelerating the leakage of proteins from the bacteria. In addition, RGDC can provide excellent biosafety and osteoconductivity, which is confirmed by in vivo animal experiments.}, } @article {pmid31507562, year = {2019}, author = {Olsen, NMC and Røder, HL and Russel, J and Madsen, JS and Sørensen, SJ and Burmølle, M}, title = {Priority of Early Colonizers but No Effect on Cohabitants in a Synergistic Biofilm Community.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1949}, pmid = {31507562}, issn = {1664-302X}, abstract = {The arrival order of different species to a habitat can strongly impact community assembly and succession dynamics, thus influencing functionality. In this study, we asked how prior colonization of one community member would influence the assembly of a synergistic multispecies biofilm community grown in vitro. We expected that the prior arrival would confer an advantage, in particular for good biofilm formers. Yet, we did not know if the cohabitants would be impaired or benefit from the pre-colonization of one member, depending on its ability to form biofilm. We used a consortium consisting of four soil bacteria; Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus. This consortium has been shown to act synergistically when grown together, thus increasing biofilm production. The results showed that the two good biofilm formers gained a fitness advantage (increase in abundance) when allowed prior colonization on an abiotic surface before the arrival of their cohabitants. Interestingly, the significantly higher number of the pre-colonized biofilm formers did not affect the resulting composition in the subsequent biofilm after 24 h.}, } @article {pmid31507548, year = {2019}, author = {Bisht, K and Wakeman, CA}, title = {Discovery and Therapeutic Targeting of Differentiated Biofilm Subpopulations.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1908}, pmid = {31507548}, issn = {1664-302X}, support = {R15 GM128072/GM/NIGMS NIH HHS/United States ; }, abstract = {The association of microorganisms into biofilms produces functionally organized microbial structures that promote community survival in a wide range of environments. Much like when individual cells within a multicellular organism express different genes from the same DNA blueprint, individual microbial cells located within different regions of a biofilm structure can exhibit distinct genetic programs. These spatially defined regions of physiologically differentiated cells are reminiscent of the role of tissues in multicellular organisms, with specific subpopulations in the microbial community serving defined roles to promote the overall health of the biofilm. The functions of these subpopulations are quite diverse and can range from dormant cells that can withstand antibiotic onslaughts to cells actively producing extracellular polymeric substances providing integrity to the entire community. The purpose of this review is to discuss the diverse roles of subpopulations in the stability and function of clonal biofilms, the methods for studying these subpopulations, and the ways these subpopulations can potentially be exploited for therapeutic intervention.}, } @article {pmid31505984, year = {2019}, author = {Lee, JH and Kim, YG and Raorane, CJ and Ryu, SY and Shim, JJ and Lee, J}, title = {The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli.}, journal = {Biofouling}, volume = {35}, number = {7}, pages = {758-767}, doi = {10.1080/08927014.2019.1657418}, pmid = {31505984}, issn = {1029-2454}, mesh = {Bacterial Adhesion/drug effects ; *Biofilms ; Escherichia coli Proteins/metabolism ; Fimbriae, Bacterial/metabolism ; Plant Extracts/*pharmacology ; Resveratrol/*pharmacology ; Stilbenes/*pharmacology ; Uropathogenic Escherichia coli/*drug effects/physiology ; Virulence/drug effects ; }, abstract = {Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 μg ml[-1]). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.}, } @article {pmid31505413, year = {2020}, author = {Cao, J and Wang, Q and Ma, T and Bao, K and Yu, X and Duan, Z and Shen, X and Li, C}, title = {Effect of EGCG-gelatin biofilm on the quality and microbial composition of tilapia fillets during chilled storage.}, journal = {Food chemistry}, volume = {305}, number = {}, pages = {125454}, doi = {10.1016/j.foodchem.2019.125454}, pmid = {31505413}, issn = {1873-7072}, mesh = {Aeromonas/drug effects ; Animals ; Biogenic Amines/analysis ; Biomimetic Materials/*chemistry/pharmacology ; Catechin/*analogs & derivatives/chemistry ; Food Storage/*methods ; Gelatin/*chemistry ; Lipid Peroxidation/drug effects ; Protein Denaturation/drug effects ; Proteins/chemistry ; Pseudomonas/drug effects ; Seafood/*analysis/microbiology ; Taste/drug effects ; Temperature ; }, abstract = {The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.}, } @article {pmid31505403, year = {2019}, author = {Ren, L and McCuskey, SR and Moreland, A and Bazan, GC and Nguyen, TQ}, title = {Tuning Geobacter sulfurreducens biofilm with conjugated polyelectrolyte for increased performance in bioelectrochemical system.}, journal = {Biosensors & bioelectronics}, volume = {144}, number = {}, pages = {111630}, doi = {10.1016/j.bios.2019.111630}, pmid = {31505403}, issn = {1873-4235}, mesh = {Biofilms/*growth & development ; Biomass ; *Biosensing Techniques ; Dielectric Spectroscopy ; *Electrochemical Techniques ; Geobacter/drug effects/*growth & development ; Polyelectrolytes/chemistry/pharmacology ; Surface Properties ; }, abstract = {Bioelectrochemical systems (BESs) are emerging as a platform technology with great application potentials such as wastewater remediation and power generation. Materials for electrode/microorganism modification are being examined in order to improve the current production in BESs. Herein, we report that the current production increased almost one fold in single-chamber BES reactors, by adding a conjugated polyelectrolyte (CPE-K) in the growth medium to co-form the anodic biofilm with Geobacter sulfurreducens cells. The CPE-K treated BESs had a maximum current density as high as 12.3 ± 0.5 A/m[2], with that of the controls being 6.2 ± 0.7 A/m[2]. Improved current production was sustained even after CPE-K was no longer added to the medium. It was demonstrated that increased current resulted from improvement of certain biofilm properties. Analysis using electrochemical impedance spectroscopy (EIS) showed that CPE-K addition decreased the charge transfer resistance at the cell/electrode interface and the diffusion resistance through the biofilm. Protein quantification showed increased biomass growth on the electrode surface, and confocal scanning microscopy images revealed enhanced biofilm permeability. These results demonstrated for the first time that conjugated polyelectrolytes could be used for G. sulfurreducens biofilm augmentation to achieve high electricity production through tuning the anodic biofilm in BESs.}, } @article {pmid31505308, year = {2019}, author = {Cui, YX and Biswal, BK and van Loosdrecht, MCM and Chen, GH and Wu, D}, title = {Long term performance and dynamics of microbial biofilm communities performing sulfur-oxidizing autotrophic denitrification in a moving-bed biofilm reactor.}, journal = {Water research}, volume = {166}, number = {}, pages = {115038}, doi = {10.1016/j.watres.2019.115038}, pmid = {31505308}, issn = {1879-2448}, mesh = {Autotrophic Processes ; Biofilms ; Bioreactors ; *Denitrification ; *Microbiota ; Nitrates ; Nitrogen ; Oxidation-Reduction ; Sulfur ; }, abstract = {Sulfide-oxidizing autotrophic denitrification (SOAD) implemented in a moving-bed biofilm reactor (MBBR) is a promising alternative to conventional heterotrophic denitrification in mainstream biological nitrogen removal. The sulfide-oxidation intermediate - elemental sulfur - is crucial for the kinetic and microbial properties of the sulfur-oxidizing bacterial communities, but its role is yet to be studied in depth. Hence, to investigate the performance and microbial communities of the aforementioned new biosystem, we operated for a long term a laboratory-scale (700 d) SOAD MBBR to treat synthetic saline domestic sewage, with an increase of the surface loading rate from 8 to 50 mg N/(m[2]·h) achieved by shortening the hydraulic retention time from 12 h to 2 h. The specific reaction rates of the reactor were eventually increased up to 0.37 kg N/(m[3]·d) and 0.73 kg S/(m[3]·d) for nitrate reduction and sulfide oxidation with no significant sulfur elemental accumulation. Two sulfur-oxidizing bacterial (SOB) clades, Sox-independent SOB (SOBI) and Sox-dependent SOB (SOBII), were responsible for indirect two-step sulfur oxidation (S[2-]→S[0]→SO4[2-]) and direct one-step sulfur oxidation (S[2-]→SO4[2-]), respectively. The SOBII biomass-specific electron transfer capacity could be around 2.5 times greater than that of SOBI (38 mmol e[-]/(gSOBII·d) versus 15 mmol e[-]/(gSOBI·d)), possibly resulting in the selection of SOBII over SOBI under stress conditions (such as a shorter HRT). Further studies on the methods and mechanism of selecting of SOBII over SOBI in biofilm reactors are recommended. Overall, the findings shed light on the design and operation of MBBR-based SOAD processes for mainstream biological denitrification.}, } @article {pmid31504755, year = {2020}, author = {Juin, C and Perrin, F and Puy, T and Bernard, C and Mollichella, ML and Girardot, M and Costa, D and Guillard, J and Imbert, C}, title = {Anti-biofilm activity of a semi-synthetic molecule obtained from resveratrol against Candida albicans biofilm.}, journal = {Medical mycology}, volume = {58}, number = {4}, pages = {530-542}, doi = {10.1093/mmy/myz087}, pmid = {31504755}, issn = {1460-2709}, mesh = {Antifungal Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/classification/*drug effects ; Drug Synergism ; Inhibitory Concentration 50 ; Micafungin/pharmacology ; Microbial Sensitivity Tests ; Proof of Concept Study ; Resveratrol/chemical synthesis/*pharmacology ; }, abstract = {Candida albicans can form biofilm on tissues and medical devices, becoming, in that case, less susceptible to antifungal agents. Treatment of candidiasis associated with the formation of C. albicans biofilms is restricted to echinocandins and lipid forms of amphotericin B. This study investigated the activity of micafungin and resveratrol modified molecule (EB487) against C. albicans biofilms. The anti-biofilm growth (Bgrowth) and anti-preformed biofilm (Bpreformed) activities of micafungin (0 to 3.94 μM) and EB487 (0 to 20.32 mM) were comparatively studied separately and combined, using XTT, flow cytometry and cell counts approaches. Concentrations causing 50% inhibition of the studied steps (IC50) were evaluated. When tested separately, IC50 Bgrowth was obtained for 4.8 mM and 0.13 μM of EB487 and micafungin respectively, and IC50 Bpreformed for 3.6 mM and 0.06 μM of EB487 and micafungin respectively. Micafungin used alone was not able to totally eradicate fungi. Micafungin combined with EB487 displayed synergistic activity (both anti-growth- and anti-preformed biofilm-activities). Optimal combination concentrations were EB487 (≤9.12 mM -strain ATCC 28367™ or ≤8.12 mM -strain CAI4-p), micafungin (≤0.05 μM for both) and caused a total eradication of fungi. Dose reduction indexes obtained using these concentrations were at least 9 (micafungin) and 3.2 (EB487) for both anti-biofilm growth- and anti-preformed biofilm-activities. Combinations indexes were consistently below one, demonstrating a synergistic relationship between micafungin and EB487 in these conditions. This study demonstrated the strong anti-biofilm activity of EB487 and highlighted its synergistic potential when combined with micafungin. EB487 is a promising semi-synthetic molecule with prophylactic and curative interests in fighting C. albicans biofilms.}, } @article {pmid31503362, year = {2019}, author = {Chan, WY and Hickey, EE and Page, SW and Trott, DJ and Hill, PB}, title = {Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants.}, journal = {Journal of veterinary pharmacology and therapeutics}, volume = {42}, number = {6}, pages = {682-692}, doi = {10.1111/jvp.12811}, pmid = {31503362}, issn = {1365-2885}, support = {LP130100736//ARC Linkage Grant/ ; //Ministry of Higher Education/ ; //Universiti Putra Malaysia/ ; }, mesh = {Acetylcysteine ; Animals ; Anti-Infective Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/drug effects/*growth & development ; Dog Diseases/*microbiology ; Dogs ; Edetic Acid ; Enrofloxacin ; Ionophores/*pharmacology ; Microbial Sensitivity Tests ; Monensin/pharmacology ; Otitis Externa/microbiology/*veterinary ; Pyrans/pharmacology ; }, abstract = {Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.}, } @article {pmid31502909, year = {2019}, author = {Silva, MD and Sillankorva, S}, title = {Otitis media pathogens - A life entrapped in biofilm communities.}, journal = {Critical reviews in microbiology}, volume = {45}, number = {5-6}, pages = {595-612}, doi = {10.1080/1040841X.2019.1660616}, pmid = {31502909}, issn = {1549-7828}, mesh = {Animals ; *Biofilms ; Haemophilus influenzae/genetics/*physiology ; Humans ; Moraxella catarrhalis/genetics/*physiology ; Otitis Media/*microbiology ; Streptococcus pneumoniae/genetics/*physiology ; }, abstract = {Otitis media is a group of inflammatory diseases of the middle ear with great impact on children worldwide. The most common reported bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Over the last years, the role of biofilms formed by otopathogens that contribute to otitis media recurrence and chronicity has been established. An improved understanding of the properties of biofilms formed by these bacteria, which factors influence them, and how these affect the host inflammatory response is important for the development of novel strategies for the treatment of otitis media. This review focuses on the biofilm nature that the most prevalent otopathogens adopt in otitis media infections. In addition, new treatment approaches targeting biofilms are highlighted.}, } @article {pmid31501280, year = {2019}, author = {Stewart, PS and White, B and Boegli, L and Hamerly, T and Williamson, KS and Franklin, MJ and Bothner, B and James, GA and Fisher, S and Vital-Lopez, FG and Wallqvist, A}, title = {Conceptual Model of Biofilm Antibiotic Tolerance That Integrates Phenomena of Diffusion, Metabolism, Gene Expression, and Physiology.}, journal = {Journal of bacteriology}, volume = {201}, number = {22}, pages = {}, pmid = {31501280}, issn = {1098-5530}, support = {P20 GM103474/GM/NIGMS NIH HHS/United States ; R01 AI113330/AI/NIAID NIH HHS/United States ; R21 AI140163/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Diffusion ; *Drug Resistance, Bacterial/genetics ; Gene Expression ; Models, Biological ; Oxygen/metabolism ; Pseudomonas aeruginosa/*drug effects/genetics/metabolism/physiology ; Stress, Physiological ; }, abstract = {Transcriptomic, metabolomic, physiological, and computational modeling approaches were integrated to gain insight into the mechanisms of antibiotic tolerance in an in vitro biofilm system. Pseudomonas aeruginosa biofilms were grown in drip flow reactors on a medium composed to mimic the exudate from a chronic wound. After 4 days, the biofilm was 114 μm thick with 9.45 log10 CFU cm[-2] These biofilms exhibited tolerance, relative to exponential-phase planktonic cells, to subsequent treatment with ciprofloxacin. The specific growth rate of the biofilm was estimated via elemental balances to be approximately 0.37 h[-1] and with a reaction-diffusion model to be 0.32 h[-1], or one-third of the maximum specific growth rate for planktonic cells. Global analysis of gene expression indicated lower transcription of ribosomal genes and genes for other anabolic functions in biofilms than in exponential-phase planktonic cells and revealed the induction of multiple stress responses in biofilm cells, including those associated with growth arrest, zinc limitation, hypoxia, and acyl-homoserine lactone quorum sensing. Metabolic pathways for phenazine biosynthesis and denitrification were transcriptionally activated in biofilms. A customized reaction-diffusion model predicted that steep oxygen concentration gradients will form when these biofilms are thicker than about 40 μm. Mutant strains that were deficient in Psl polysaccharide synthesis, the stringent response, the stationary-phase response, and the membrane stress response exhibited increased ciprofloxacin susceptibility when cultured in biofilms. These results support a sequence of phenomena leading to biofilm antibiotic tolerance, involving oxygen limitation, electron acceptor starvation and growth arrest, induction of associated stress responses, and differentiation into protected cell states.IMPORTANCE Bacteria in biofilms are protected from killing by antibiotics, and this reduced susceptibility contributes to the persistence of infections such as those in the cystic fibrosis lung and chronic wounds. A generalized conceptual model of biofilm antimicrobial tolerance with the following mechanistic steps is proposed: (i) establishment of concentration gradients in metabolic substrates and products; (ii) active biological responses to these changes in the local chemical microenvironment; (iii) entry of biofilm cells into a spectrum of states involving alternative metabolisms, stress responses, slow growth, cessation of growth, or dormancy (all prior to antibiotic treatment); (iv) adaptive responses to antibiotic exposure; and (v) reduced susceptibility of microbial cells to antimicrobial challenges in some of the physiological states accessed through these changes.}, } @article {pmid31501144, year = {2019}, author = {Richards, JP and Cai, W and Zill, NA and Zhang, W and Ojha, AK}, title = {Adaptation of Mycobacterium tuberculosis to Biofilm Growth Is Genetically Linked to Drug Tolerance.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {11}, pages = {}, pmid = {31501144}, issn = {1098-6596}, support = {DP2 AT009148/AT/NCCIH NIH HHS/United States ; R01 AI132422/AI/NIAID NIH HHS/United States ; R21 AI144474/AI/NIAID NIH HHS/United States ; S10 OD020062/OD/NIH HHS/United States ; }, mesh = {Adaptation, Physiological/drug effects ; Antitubercular Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Drug Resistance, Bacterial/genetics ; Mycobacterium tuberculosis/drug effects/genetics/*growth & development ; }, abstract = {Mycobacterium tuberculosis spontaneously grows at the air-medium interface, forming pellicle biofilms, which harbor more drug-tolerant persisters than planktonic cultures. The underlying basis for increased persisters in M. tuberculosis biofilms is unknown. Using a transposon sequencing (Tn-seq) approach, we show here that multiple genes that are necessary for fitness of M. tuberculosis cells within biofilms, but not in planktonic cultures, are also implicated in tolerance of bacilli to a diverse set of stressors and antibiotics. Thus, development of M. tuberculosis biofilms appears to be associated with an enrichment of population, in which challenging growth conditions within biofilm architecture select for cells that maintain intrinsic tolerance to exogenous stresses, including antibiotic exposure. We further observed that the intrinsic drug tolerance of constituent cells of a biofilm determines the frequency of persisters. These findings together allow us to propose that the selection of elite cells during biofilm development promotes the frequency of persisters. Furthermore, probing the possibility that the population enrichment is an outcome of unique environment within biofilms, we demonstrate biofilm-specific induction in the synthesis of isonitrile lipopeptide (INLP). Mutation analysis indicates that INLP is necessary for the architecture development of M. tuberculosis biofilms. In summary, this study offers an insight into persistence of M. tuberculosis biofilms under antibiotic exposure, while identifying INLP as a potential biomarker for further investigation of this phenomenon.}, } @article {pmid31500093, year = {2019}, author = {Ratka, C and Weigl, P and Henrich, D and Koch, F and Schlee, M and Zipprich, H}, title = {The Effect of In Vitro Electrolytic Cleaning on Biofilm-Contaminated Implant Surfaces.}, journal = {Journal of clinical medicine}, volume = {8}, number = {9}, pages = {}, pmid = {31500093}, issn = {2077-0383}, abstract = {PURPOSE: Bacterial biofilms are a major problem in the treatment of infected dental and orthopedic implants. The purpose of this study is to investigate the cleaning effect of an electrolytic approach (EC) compared to a powder-spray system (PSS) on titanium surfaces.

MATERIALS AND METHODS: The tested implants (different surfaces and alloys) were collated into six groups and treated ether with EC or PSS. After a mature biofilm was established, the implants were treated, immersed in a nutritional solution, and streaked on Columbia agar. Colony-forming units (CFUs) were counted after breeding and testing (EC), and control (PSS) groups were compared using a paired sample t-test.

RESULTS: No bacterial growth was observed in the EC groups. After thinning to 1:1,000,000, 258.1 ± 19.9 (group 2), 264.4 ± 36.5 (group 4), and 245.3 ± 40.7 (group 6) CFUs could be counted in the PSS groups. The difference between the electrolytic approach (test groups 1, 3, and 5) and PSS (control groups 2, 4, and 6) was statistically extremely significant (p-value < 2.2 × 10[-16]).

CONCLUSION: Only EC inactivated the bacterial biofilm, and PSS left reproducible bacteria behind. Within the limits of this in vitro test, clinical relevance could be demonstrated.}, } @article {pmid31500048, year = {2019}, author = {de Carvalho, FG and Magalhães, TC and Teixeira, NM and Gondim, BLC and Carlo, HL and Dos Santos, RL and de Oliveira, AR and Denadai, ÂML}, title = {Synthesis and characterization of TPP/chitosan nanoparticles: Colloidal mechanism of reaction and antifungal effect on C. albicans biofilm formation.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {104}, number = {}, pages = {109885}, doi = {10.1016/j.msec.2019.109885}, pmid = {31500048}, issn = {1873-0191}, mesh = {Antifungal Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Chitosan/*analogs & derivatives/*chemistry ; Colloids/*chemistry ; Gels/chemistry ; Nanoparticles/*chemistry ; Nystatin/chemistry ; Polyphosphates/chemistry ; }, abstract = {In the present study chitosan (Chit) nanoparticles were synthetized by the ionic gelation process, using tripolyphosphate (TPP) as crosslinking agent. The TPP/Chit nanoparticle formation was evaluated by titrations, measuring electrical conductivity (k), zeta potential (ZP), hydrodynamic diameter (Dh), viscosity (η) and heat by isothermal calorimetry (ITC). The antifungal effects were evaluated by C. albicans time-kill assays, inhibition of C. albicans initial adhesion and biofilm formation in comparison with nystatin and chitosan. Conductometric titration exhibited a typical precipitation profile, with an inflection at molar ratio of [TPP]/[Chitmon] ≈ 0.3, suggesting a 1:3.3 stoichiometry. The highest Dh, ZP and η values were shown at the beginning of titrations, due to the intramolecular repulsion between Chit-Chit. With addition of TPP, the values showed gradual reduction, with an intermediary transition at [TPP]/[Chitmon] ≈ 0.16, which was attributed to the partial breakdown of interchain crosslinking and formation of discrete charged aggregates. After this point, reaction should occur by neutralization of these assemblies, causing new reduction in values of Dh, ZP and η until [TPP]/[Chitmon] ≈ 0.3, when they reached their lowest values. ITC experiment also showed the occurrence of two bindings (K1 = 3.6 × 10[3] and K2 = 7.7 × 10[4]), which were entropy driven. Biological results showed lower C. albicans viability for TPP/Chit over 24 h compared with chitosan and nystatin at MIC and 2 MIC. Moreover, TPP/Chit showed 25-50% inhibition of C. albicans adhesion and biofilm formation. The results showed that TPP/Chit nanoparticles reduced the initial adhesion and biofilm formation of C. albicans and demonstrated potential for use in a formulation for the treatment of oral candidiasis.}, } @article {pmid31500022, year = {2019}, author = {Jung, J and Li, L and Yeh, CK and Ren, X and Sun, Y}, title = {Amphiphilic quaternary ammonium chitosan/sodium alginate multilayer coatings kill fungal cells and inhibit fungal biofilm on dental biomaterials.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {104}, number = {}, pages = {109961}, doi = {10.1016/j.msec.2019.109961}, pmid = {31500022}, issn = {1873-0191}, mesh = {Alginates/*chemistry ; Ammonium Compounds/*chemistry ; Anti-Infective Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Chitosan/*chemistry ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Dental Materials/chemistry/*pharmacology ; Polymethyl Methacrylate/pharmacology ; Spectroscopy, Fourier Transform Infrared/methods ; Surface Properties/drug effects ; }, abstract = {Formation of fungal biofilms on health care-related materials causes serious clinical consequences. This study reports a novel fungal repelling strategy to control fungal biofilm formation on denture biomaterials through layer-by-layer self-assembly (LBL). Amphiphilic quaternary ammonium chitosans (CS612) were synthesized and used as the antimicrobial positive layer, and sodium alginate (SA) was chosen as the negative layer to construct LBL multilayers on poly (methyl methacrylate) (PMMA)-based denture materials. The presence of LBL multilayers on denture disc was confirmed and characterized by surface zeta potential, water contact angle, AFM, and FT-IR analyses. The multilayer coatings, especially CS612 as the outmost layer, effectively prevented the fungal initial adhesion and biofilm formation. The Candida cells avoided the multilayer coatings and suspended in broth solution instead of forming biofilms, suggesting that the LBL multilayers had fungal repelling effects. The LBL multilayers were biocompatible toward mammalian cells. In stability tests, after immersion in PBS for 4 weeks under constant shaking and repeated brushing with a denture brush for up to 3000 times, the biofilm-controlling effects of the LBL multilayers were not affected, pointing to a novel long-term strategy in controlling fungal biofilms on denture and other related biomaterials.}, } @article {pmid31499329, year = {2019}, author = {Brück, HL and Delvigne, F and Dhulster, P and Jacques, P and Coutte, F}, title = {Molecular strategies for adapting Bacillus subtilis 168 biosurfactant production to biofilm cultivation mode.}, journal = {Bioresource technology}, volume = {293}, number = {}, pages = {122090}, doi = {10.1016/j.biortech.2019.122090}, pmid = {31499329}, issn = {1873-2976}, mesh = {*Bacillus subtilis ; Biofilms ; Bioreactors ; *Lipopeptides ; Peptides, Cyclic ; }, abstract = {Biofilm bioreactors have already been proven to be efficient systems for microbial lipopeptide production since they avoid foam formation. However, the cell adhesion capacities of the laboratory strain B.subtilis 168 to the biofilm bioreactor support are limited. In this work, we present a novel approach for increasing cell adhesion through the generation of filamentous and/or exopolysaccharide producing B.subtilis 168 mutants by genetic engineering. The single cell growth behavior was analyzed using time-lapse microscopy and the colonization capacities were investigated under continuous flow conditions in a drip-flow reactor. Cell adhesion could be increased three times through filamentous growth in lipopeptide producing B. subtilis 168 derivatives strains. Further restored exopolysaccharide production increased up to 50 times the cell adhesion capacities. Enhanced cell immobilization resulted in 10 times increased surfactin production. These findings will be of particular interest regarding the design of more efficient microbial cell factories for biofilm cultivation.}, } @article {pmid31498302, year = {2019}, author = {Depetris, A and Wiedmer, A and Wagner, M and Schäfer, S and Battin, TJ and Peter, H}, title = {Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large Spatial Scales.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {150}, pages = {}, doi = {10.3791/59356}, pmid = {31498302}, issn = {1940-087X}, mesh = {Automation ; Biofilms/*growth & development ; Image Interpretation, Computer-Assisted/*methods ; Imaging, Three-Dimensional/*methods ; *Morphogenesis ; *Software ; Tomography, Optical Coherence/*methods ; }, abstract = {Biofilms are a most successful microbial lifestyle and prevail in a multitude of environmental and engineered settings. Understanding biofilm morphogenesis, that is the structural diversification of biofilms during community assembly, represents a remarkable challenge across spatial and temporal scales. Here, we present an automated biofilm imaging system based on optical coherence tomography (OCT). OCT is an emerging imaging technique in biofilm research. However, the amount of data that currently can be acquired and processed hampers the statistical inference of large scale patterns in biofilm morphology. The automated OCT imaging system allows covering large spatial and extended temporal scales of biofilm growth. It combines a commercially available OCT system with a robotic positioning platform and a suite of software solutions to control the positioning of the OCT scanning probe, as well as the acquisition and processing of 3D biofilm imaging datasets. This setup allows the in situ and non-invasive automated monitoring of biofilm development and may be further developed to couple OCT imaging with macrophotography and microsensor profiling.}, } @article {pmid31497539, year = {2019}, author = {Singh, VK and Mishra, A and Jha, B}, title = {Corrigendum: Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {308}, pmid = {31497539}, issn = {2235-2988}, abstract = {[This corrects the article DOI: 10.3389/fcimb.2017.00337.].}, } @article {pmid31493577, year = {2020}, author = {Zhu, L and Chen, T and Xu, L and Zhou, Z and Feng, W and Liu, Y and Chen, H}, title = {Effect and mechanism of quorum sensing on horizontal transfer of multidrug plasmid RP4 in BAC biofilm.}, journal = {The Science of the total environment}, volume = {698}, number = {}, pages = {134236}, doi = {10.1016/j.scitotenv.2019.134236}, pmid = {31493577}, issn = {1879-1026}, mesh = {Acyl-Butyrolactones/*metabolism ; *Biofilms ; Charcoal ; Drinking Water/microbiology ; Gene Transfer, Horizontal ; Plasmids ; *Quorum Sensing ; }, abstract = {The widespread emergence of antibiotic resistance genes (ARGs) in drinking water systems endangers human health, and may be exacerbated by their horizontal gene transfer (HGT) among microbiota. In our previous study, Quorum sensing (QS) molecules produced by bacteria from biological activated carbon (BAC) biofilms were demonstrated to influence the transfer efficiency of a model conjugative plasmid, here RP4. In this study, we further explored the effect and mechanism of QS on conjugation transfer. The results revealed that Acyl-homoserine lactones producing (AHL-producing) bacteria isolated from BAC biofilm play a role in the propagation of ARGs. We selected several quorum sensing inhibitors (QSIs) to study their effects on AHL-producing bacteria, including the formation of biofilm and the regulating effect on conjugation transfer. In addition, the possible molecular mechanisms for AHLs that promote conjugative transfer were attributable to enhancing the mRNA expression, which involved altered expressions of conjugation-related genes. We also found that QSIs could inhibit conjugative transfer by downregulating the conjugation-relevant genes. We believe that this is the first insightful exploration of the mechanism by which AHLs will facilitate and QSIs will inhibit the conjugative transfer of ARGs. These results provide creative insight into ARG pollution control that involves blocking QS during BAC treatment in drinking water systems.}, } @article {pmid31493571, year = {2020}, author = {Ngan, WY and Habimana, O}, title = {From farm-scale to lab-scale: The characterization of engineered irrigation water distribution system biofilm models using an artificial freshwater source.}, journal = {The Science of the total environment}, volume = {698}, number = {}, pages = {134025}, doi = {10.1016/j.scitotenv.2019.134025}, pmid = {31493571}, issn = {1879-1026}, mesh = {Agricultural Irrigation/*methods ; Biofilms ; Farms ; Fresh Water ; Water Microbiology ; Water Quality ; }, abstract = {Contaminants in freshwater environments, as well as the associated negative impacts on agricultural produce, have emerged as a critical theme of the water-energy-food nexus affecting food safety and irrigation management. Agricultural produce exposed to irrigation with questionable freshwater can internalize and concentrate pollutants. However, the potential risks posed by the ubiquitous presence of biofilms within irrigation water distribution systems (IWDS) remains overlooked, even though such biofilms may harbor and spread pathogenic, chemical, and other environmental pollutants. Our limited knowledge about the role and functional attributes of IWDS biofilms can be blamed mostly to experimental challenges encountered during attempted studies of these biofilms in their natural environments. Hence, a laboratory-based experimental system designed to simulate a freshwater environment was combined with a biofilm reactor capable of recreating the piping environments in water distribution systems. This experimental system was then tested to assess the robustness and repeatability of experimental early-stage biofilms with respect to physical structure and microbial community, using state-of-the-art confocal microscopy and next-generation sequencing, respectively. The results demonstrated the suitability of this laboratory-based experimental system for studying the impacts of selected pollutants on irrigation water distribution systems.}, } @article {pmid31493408, year = {2020}, author = {Milton, ME and Draughn, GL and Bobay, BG and Stowe, SD and Olson, AL and Feldmann, EA and Thompson, RJ and Myers, KH and Santoro, MT and Kearns, DB and Cavanagh, J}, title = {The Solution Structures and Interaction of SinR and SinI: Elucidating the Mechanism of Action of the Master Regulator Switch for Biofilm Formation in Bacillus subtilis.}, journal = {Journal of molecular biology}, volume = {432}, number = {2}, pages = {343-357}, pmid = {31493408}, issn = {1089-8638}, support = {R01 GM055769/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Sequence/genetics ; Bacillus subtilis/genetics/*ultrastructure ; Bacterial Proteins/chemistry/genetics/*ultrastructure ; Biofilms/growth & development ; DNA-Binding Proteins/chemistry/genetics/*ultrastructure ; Gene Expression Regulation, Bacterial/genetics ; Molecular Docking Simulation ; Mutation/genetics ; Protein Binding/genetics ; Protein Conformation ; }, abstract = {Bacteria have developed numerous protection strategies to ensure survival in harsh environments, with perhaps the most robust method being the formation of a protective biofilm. In biofilms, bacterial cells are embedded within a matrix that is composed of a complex mixture of polysaccharides, proteins, and DNA. The gram-positive bacterium Bacillus subtilis has become a model organism for studying regulatory networks directing biofilm formation. The phenotypic transition from a planktonic to biofilm state is regulated by the activity of the transcriptional repressor, SinR, and its inactivation by its primary antagonist, SinI. In this work, we present the first full-length structural model of tetrameric SinR using a hybrid approach combining high-resolution solution nuclear magnetic resonance (NMR), chemical cross-linking, mass spectrometry, and molecular docking. We also present the solution NMR structure of the antagonist SinI dimer and probe the mechanism behind the SinR-SinI interaction using a combination of biochemical and biophysical techniques. As a result of these findings, we propose that SinI utilizes a residue replacement mechanism to block SinR multimerization, resulting in diminished DNA binding and concomitant decreased repressor activity. Finally, we provide an evidence-based mechanism that confirms how disruption of the SinR tetramer by SinI regulates gene expression.}, } @article {pmid31493142, year = {2019}, author = {Memariani, H and Memariani, M and Ghasemian, A}, title = {An overview on anti-biofilm properties of quercetin against bacterial pathogens.}, journal = {World journal of microbiology & biotechnology}, volume = {35}, number = {9}, pages = {143}, pmid = {31493142}, issn = {1573-0972}, mesh = {Bacteria/*drug effects ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects ; Cell Wall/drug effects ; Microbial Sensitivity Tests ; Nucleic Acid Synthesis Inhibitors/pharmacology ; Nucleic Acids/biosynthesis ; Quercetin/*pharmacology ; Quorum Sensing/drug effects ; }, abstract = {Bacterial biofilms are multicellular aggregates enclosed in a self-created biopolymer matrix. Biofilm-producing bacteria have become a great public health problem worldwide because biofilms enable these microorganisms to evade several clearance mechanisms produced by host and synthetic sources. Over the past years, different flavonoids including quercetin have engrossed considerable interest among researchers owing to their potential anti-biofilm properties. To our knowledge, there is no review regarding effects of quercetin towards bacterial biofilms, prompting us to summarize experimental evidence on its anti-biofilm properties. Quercetin inhibits biofilm development by a diverse array of bacterial pathogens such as Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Pseudomonas aeruginosa. Prevention of bacterial adhesion, suppression of quorum-sensing pathways, disruption or alteration of plasma membrane, inhibition of efflux pumps, and blocking nucleic acid synthesis have been documented as major anti-biofilm mechanisms of quercetin. Overall, anti-biofilm activity of quercetin can open up new horizons in a wide range of biomedical areas, from food industry to medicine.}, } @article {pmid31492289, year = {2020}, author = {Harpale, K and Jagtap, K and Bankar, A and Dhole, S and More, M}, title = {Synthesis, Characterization and Anti-Biofilm Efficacy of Polypyrrole-Zinc Oxide Composites.}, journal = {Journal of nanoscience and nanotechnology}, volume = {20}, number = {4}, pages = {2639-2644}, doi = {10.1166/jnn.2020.17367}, pmid = {31492289}, issn = {1533-4899}, abstract = {A nanocomposite of Polypyrrole (PPy) and zinc oxide (ZnO), termed as PPy-ZnO, was synthesized by two step route. In the first step, synthesis of PPy was carried out by chemical oxidative route. In the second step, the PPy-ZnO nanocomposite was synthesized under hydrothermal conditions. The as-synthesized PPy-ZnO nanocomposites were characterized using X-ray Diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infra-red (FTIR) and Ultra violetvisible (UV-vis) spectroscopy to reveal the phase, morphology, chemical and optical properties. The physical and chemical characterizations confirmed presence of both PPy and ZnO phases in the nanocomposite. In the present work, antimicrobial activity of the PPy-ZnO nanocomposite against human pathogen Y. lipolytica has been investigated. Attempts have been made to reveal the influence of PPy percentage on the antimicrobial activity. Interestingly, all PPy-ZnO nanocomposites, irrespective of PPy percentage, showed 90 to 95% inhibited growth of Yarrowia lipolytica. The results obtained herein imply the potential of PPy-ZnO biofilm in inhibiting the growth of Y. lipolytica and thus preventing infections caused due to Y. lipolytica in humans.}, } @article {pmid31491442, year = {2019}, author = {Goeres, DM and Walker, DK and Buckingham-Meyer, K and Lorenz, L and Summers, J and Fritz, B and Goveia, D and Dickerman, G and Schultz, J and Parker, AE}, title = {Development, standardization, and validation of a biofilm efficacy test: The single tube method.}, journal = {Journal of microbiological methods}, volume = {165}, number = {}, pages = {105694}, doi = {10.1016/j.mimet.2019.105694}, pmid = {31491442}, issn = {1872-8359}, mesh = {Alcohols/toxicity ; Anti-Bacterial Agents/*toxicity ; Bias ; *Biofilms/drug effects/growth & development ; Disinfectants/*toxicity ; Hydroxybenzoates/toxicity ; *Pseudomonas aeruginosa/drug effects/growth & development ; Quaternary Ammonium Compounds/toxicity ; Reference Standards ; Sodium Hypochlorite/toxicity ; Surface Properties ; }, abstract = {Methods validated by a standard setting organization enable public, industry and regulatory stakeholders to make decisions on the acceptability of products, devices and processes. This is because standard methods are demonstrably reproducible when performed in different laboratories by different researchers, responsive to different products, and rugged when small (usually inadvertent) variations from the standard procedure occur. The Single Tube Method (ASTM E2871) is a standard method that measures the efficacy of antimicrobials against biofilm bacteria that has been shown to be reproducible, responsive and rugged. In support of the reproducibility assessment, a six-laboratory study was performed using three antimicrobials: a sodium hypochlorite, a phenolic and a quaternary/alcohol blend, each tested at low and high efficacy levels. The mean log reduction in viable bacteria in this study ranged from 2.32 to 4.58 and the associated reproducibility standard deviations ranged from 0.89 to 1.67. Independent follow-up testing showed that the method was rugged with respect to deviations in sonication duration and sonication power but slightly sensitive to sonicator reservoir degassing and tube location within the sonicator bath. It was also demonstrated that when a coupon was dropped into a test tube, bacteria can splash out of reach of the applied antimicrobials, resulting in substantial bias when estimating log reductions for the products tested. Bias can also result when testing products that hinder the harvesting of microbes from test surfaces. The culmination of this work provided recommended changes to the early version of the standard method E2871-13 (ASTM, 2013b) including use of splashguards and microscopy checks. These changes have been incorporated into a revised ASTM method E2871-19 (ASTM 2019) that is the basis for the first regulatory method (ATMP-MB-20) to substantiate "kills biofilm" claims for antimicrobials registered and sold in the US.}, } @article {pmid31490650, year = {2019}, author = {Wang, J and Chen, XY and Zhao, Y and Yang, Y and Wang, W and Wu, C and Yang, B and Zhang, Z and Zhang, L and Liu, Y and Du, X and Li, W and Qiu, L and Jiang, P and Mou, XZ and Li, YQ}, title = {pH-Switchable Antimicrobial Nanofiber Networks of Hydrogel Eradicate Biofilm and Rescue Stalled Healing in Chronic Wounds.}, journal = {ACS nano}, volume = {13}, number = {10}, pages = {11686-11697}, doi = {10.1021/acsnano.9b05608}, pmid = {31490650}, issn = {1936-086X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Hydrogels/*chemistry ; Hydrogen-Ion Concentration ; Microscopy, Atomic Force ; Microscopy, Electron, Transmission ; Nanofibers/*chemistry ; Wound Healing/physiology ; }, abstract = {Biofilm infections can induce chronic inflammation and stall the normal orchestrated course of wound-healing cascades. Herein, pH-switchable antimicrobial hydrogel with nanofiber networks for biofilm eradication and rescuing stalled healing in chronic wounds is reported on the basis of the self-assembly of a designed octapeptide (IKFQFHFD) at neutral pH. This hydrogel is biocompatible and exhibits an acidic pH (pathological environment of infected chronic wounds)-switchable broad-spectrum antimicrobial effect via a mechanism involving cell wall and membrane disruption. The antimicrobial activity of hydrogel is derived from its acidic pH-dependent nanofiber network destabilization and activated release of IKFQFHFD, which is antimicrobial only at acidic pH due to the antimicrobial peptide-like molecular structure. In addition, supramolecular nanofiber networks loaded with drugs of cypate (photothermal agent) and proline (procollagen component) are further developed. In vitro experiments show that loaded drugs exhibit acidic pH (pH ∼ 5.5)-responsive release profiles, and synergistic biofilm eradication and subsequent healing cascade activation of cells proliferation are achieved on the basis of the supramolecular nanofiber networks. Remarkably, the nanofiber networks of hydrogel enable in vivo complete healing of MRSA biofilm infected wound in diabetic mice within 20 days, showing great potential as promising chronic wound dressings. The proposed synergistic strategy for eradicating biofilm and activating subsequent healing cascades may offer a powerful modality for the management of clinical chronic wounds.}, } @article {pmid31489410, year = {2019}, author = {Wang, J and Zhao, S and Ran, SJ and Sun, Z and Liang, JP}, title = {[In vitro study of antimicrobial efficacy of different irrigations on Enterococcus faecalis biofilm formation in root canal].}, journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology}, volume = {28}, number = {3}, pages = {246-250}, pmid = {31489410}, issn = {1006-7248}, mesh = {*Anti-Infective Agents/pharmacology ; Biofilms/drug effects ; *Dental Pulp Cavity ; *Enterococcus faecalis/drug effects ; Humans ; *Root Canal Irrigants/pharmacology ; Sodium Hypochlorite ; }, abstract = {PURPOSE: To compare the antimicrobial effect of different irrigations on Enterococcus faecalis biofilms in extracted teeth and evaluate the antimicrobial activity of irrigating solutions residual against E. faecalis biofilms formation, in order to provide a better strategy for clinician.

METHODS: Extracted human premolar teeth with single root canal were clearly autoclaved. These teeth were contaminated with E. faecalis（ATCC33186） and incubated for 60 days. The samples were randomly assigned to 4 experimental groups. During biomechanical instrumentation, the root canal was irrigated with different irrigating agents. The bacteria samples were collected with sterile paper points before and after instrumentation to F2. Then, samples that had been instrumented and autoclaved again were randomly divided into 2 groups treated with normal saline and 1%NaOCl for 30 min. E. faecalis was used to contaminate these root canals. The bacteria samples were collected with sterile paper points after 2, 6, 24, 48 h. SPSS19.0 software package was used for statistical analysis.

RESULTS: Group using 1% NaOCI with ultrasound devices was significantly more effective than NS alone groups. 1% NaOCI groups showed a better residual activity than NS group.

CONCLUSIONS: NaOCl is still the most important irrigating solutions, and it could be a better choice after biomechanical instrumentation, because of its long time substantivity achieves residual antimicrobial activity. Ultrasound devices is recommended to coordinate with irrigation.}, } @article {pmid31489127, year = {2019}, author = {Abdullah, N and Al-Marzooq, F and Mohamad, S and Abd Rahman, N and Chi Ngo, H and Perera Samaranayake, L}, title = {Intraoral appliances for in situ oral biofilm growth: a systematic review.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1647757}, pmid = {31489127}, issn = {2000-2297}, abstract = {Background: Oral biofilms are the root cause of major oral diseases. As in vitro biofilms are not representative of the intraoral milieu, various devices have been manufactured over the years to develop Appliance Grown Oral Biofilm (AGOB). Objective: To review various intraoral appliances used to develop AGOB for microbiological analysis, and to judge the optimal means for such analyses. Design: Four databases (PubMed, Science Direct, Scopus and Medline) were searched by two independent reviewers, and articles featuring the key words 'device' OR 'splint' OR 'appliance'; 'Oral biofilm' OR 'dental plaque'; 'in vivo' OR 'in situ'; 'Microbiology' OR 'Bacteria' OR 'microbiome'; were included. The standard Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) were adopted for data gathering. Results: Of the 517 articles which met the initial inclusion criteria, 24 were deemed eligible for review. The age of the AGOB, sampled at various intervals, ranged from 30 min to 28 days. The most commonly used microbiome analytical methods were fluorescence microscopy, total cell count using conventional, and molecular tools including Next Generation Sequencing (NGS) platforms. Conclusions: No uniformly superior method for collecting AGOB could be discerned. NGS platforms are preferable for AGOB analyses.}, } @article {pmid31487498, year = {2019}, author = {Sheraton, MV and Melnikov, VR and Sloot, PMA}, title = {Prediction and quantification of bacterial biofilm detachment using Glazier-Graner-Hogeweg method based model simulations.}, journal = {Journal of theoretical biology}, volume = {482}, number = {}, pages = {109994}, doi = {10.1016/j.jtbi.2019.109994}, pmid = {31487498}, issn = {1095-8541}, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Computer Simulation ; *Hydrodynamics ; Pseudomonas aeruginosa/physiology ; Shear Strength/physiology ; *Stress, Mechanical ; }, abstract = {Morphological changes in bacterial biofilm structures arise from the fluid-structure interactions between the biofilm and the surrounding fluid. Depending on the magnitude of the force acting on the structure, the bacteria rearrange to attain an equilibrium shape or get washed away by the moving fluid. Understanding the dynamics behind the evolution of such equilibrium or failed states can aid in development of tools for biofilm removal or eradication. We develop a Glazier-Graner-Hogeweg method-based model to explore the collective evolution of biofilm morphology arising from cell-cell and cell-fluid interactions. We show that low adherence and high motility of the cells leads to sloughing of biofilms. Also, streamers are found to form under laminar flow conditions in tightly packed biofilms. In mixed species biofilms, we found that a species with less cell-cell binding affinity gets eroded faster than its counterpart. Therefore, we hypothesize that in nature these less-adherent species should be present encapsulated within the biofilm structure to maximize their chances of survival.}, } @article {pmid31487117, year = {2019}, author = {Malone, M and Schwarzer, S and Radzieta, M and Jeffries, T and Walsh, A and Dickson, HG and Micali, G and Jensen, SO}, title = {Effect on total microbial load and community composition with two vs six-week topical Cadexomer Iodine for treating chronic biofilm infections in diabetic foot ulcers.}, journal = {International wound journal}, volume = {16}, number = {6}, pages = {1477-1486}, pmid = {31487117}, issn = {1742-481X}, support = {//Smith and Nephew/ ; }, mesh = {Administration, Topical ; Anti-Infective Agents, Local/*administration & dosage ; Bacteria/genetics/isolation & purification ; Bacterial Load/*drug effects ; Biofilms/*drug effects ; Cohort Studies ; DNA, Bacterial ; Diabetic Foot/*drug therapy ; Drug Administration Schedule ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Iodophors/*administration & dosage ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; Pilot Projects ; Wound Healing ; Wound Infection/*drug therapy ; }, abstract = {This study compares two vs six weeks of topical antimicrobial therapy with Cadexomer Iodine in patients with diabetic foot ulcers (DFUs) complicated by chronic biofilm infections. Patients with non-healing DFUs with suspected chronic biofilm infections were eligible for enrolment. Patients were randomised to receive either two or six weeks of treatment with topical Cadexomer Iodine. Tissue biopsies from the ulcers were obtained pre-and-post treatment and underwent DNA sequencing and real-time quantitative polymerase chain reaction (PCR) to determine the total microbial load, community composition, and diversity of bacteria. Scanning electron microscopy confirmed biofilm in all 18 ulcers with suspected chronic biofilm infections. Cadexomer Iodine resulted in 14 of 18 (78%) samples achieving a mean 0.5 log10 reduction in microbial load. Regardless of treatment duration, there was no statistical difference in the reduction of total microbial loads. No difference in the rate of wound healing in the two groups was seen at 6 weeks. Cadexomer Iodine reduces the total microbial load in DFUs with chronic biofilm infections and affects microbial community composition and diversity. All ulcers in both groups showed an initial reduction in wound size with application of Cadexomer Iodine, which might reflect its effect on biofilms.}, } @article {pmid31485973, year = {2020}, author = {Vergis, J and Malik, SVS and Pathak, R and Kumar, M and Sunitha, R and Barbuddhe, SB and Rawool, DB}, title = {Efficacy of Indolicidin, Cecropin A (1-7)-Melittin (CAMA) and Their Combination Against Biofilm-Forming Multidrug-Resistant Enteroaggregative Escherichia coli.}, journal = {Probiotics and antimicrobial proteins}, volume = {12}, number = {2}, pages = {705-715}, doi = {10.1007/s12602-019-09589-8}, pmid = {31485973}, issn = {1867-1314}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Escherichia coli/*drug effects ; }, abstract = {The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco's modified Eagle's medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.}, } @article {pmid31485710, year = {2020}, author = {Raouia, H and Hamida, B and Khadidja, A and Ahmed, L and Abdelwaheb, C}, title = {Effect of static magnetic field (200 mT) on biofilm formation in Pseudomonas aeruginosa.}, journal = {Archives of microbiology}, volume = {202}, number = {1}, pages = {77-83}, doi = {10.1007/s00203-019-01719-8}, pmid = {31485710}, issn = {1432-072X}, mesh = {Biofilms/*radiation effects ; Flagellin/genetics ; Gene Expression Regulation, Bacterial/radiation effects ; *Magnetic Fields ; Pseudomonas aeruginosa/genetics/*physiology/radiation effects ; }, abstract = {Several studies have investigated the effects of ionizing and non-ionizing radiations on microorganisms. However, the interaction between the magnetic field radiations and bacteria is less studied. The aim of our study was to study the effect of static magnetic field on the biofilm formation in Pseudomonas aeruginosa and its isogenic sod mutants. Our results revealed that the exposure to the static magnetic field (200 mT) increases significantly the swarming in the wild strain. The fliC gene expression did not show significant difference after 6 h exposure of the wild-type strain. The release of some compounds of the biofilm matrix such as rhamnolipids has been considerably enhanced after 6 h of exposure in the wild type. On the other hand, the pyocyanin and biofilm production was increased significantly in all strains compared to controls. Furthermore, our results revealed that the biofilm formation was confirmed by the pslA and ppyR gene expressions.}, } @article {pmid31485510, year = {2019}, author = {Hemdan, BA and El-Liethy, MA and ElMahdy, MEI and El-Taweel, GE}, title = {Metagenomics analysis of bacterial structure communities within natural biofilm.}, journal = {Heliyon}, volume = {5}, number = {8}, pages = {e02271}, pmid = {31485510}, issn = {2405-8440}, abstract = {The bacterial profiles of natural household biofilm have not been widely investigated. The majorities of these bacterial lineages are not cultivable. Thus, this study aims (i) to enumerate some potential bacterial lineages using culture based method within biofilm samples and confirmed using Biolog GEN III and polymerase chain reaction (PCR). (ii) To investigate the bacterial profiles of communities in two biofilm samples using next generation sequencing (NGS). Forty biofilm samples were cultured and colonies of each selected prevailing potential lineages (E. coli, Salmonella entrica, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes) were selected for confirmation. From obtained results, the counts of the tested bacterial lineages in kitchen biofilm samples were greater than those in bathroom samples. Precision of PCR was higher than Biolog GEN III to confirm the bacterial isolates. Using NGS analysis, the results revealed that a total of 110,554 operational taxonomic units (OTUs) were obtained for two biofilm samples, representing kitchen and bathroom biofilm samples. The numbers of phyla in the kitchen biofilm sample (35 OTUs) was higher than that in bathroom sample (18 OTUs). A total of 435 genera were observed in the bathroom biofilm sample compared to only 256 in the kitchen sample. Evidences have shown that the empirical gadgets for biofilm investigation are becoming convenient and affordable. Many distinct bacterial lineages observed in biofilm are one of the most significant issues that threaten human health and lead to disease outbreaks.}, } @article {pmid31485170, year = {2019}, author = {Al-Shabib, NA and Husain, FM and Khan, RA and Khan, MS and Alam, MZ and Ansari, FA and Laeeq, S and Zubair, M and Shahzad, SA and Khan, JM and Alsalme, A and Ahmad, I}, title = {Interference of phosphane copper (I) complexes of β-carboline with quorum sensing regulated virulence functions and biofilm in foodborne pathogenic bacteria: A first report.}, journal = {Saudi journal of biological sciences}, volume = {26}, number = {2}, pages = {308-316}, pmid = {31485170}, issn = {1319-562X}, abstract = {Foodborne pathogens are one of the major cause of food-related diseases and food poisoning. Bacterial biofilms and quorum sensing (QS) mechanism of cell-cell communication have also been found to be associated with several outbreaks of foodborne diseases and are great threat to food safety. Therefore, In the present study, we investigated the activity of three tetrahedrally coordinated copper(I) complexes against quorum sensing and biofilms of foodborne bacteria. All the three complexes demonstrated similar antimicrobial properties against the selected pathogens. Concentration below the MIC i.e. at sub-MICs all the three complexes interfered significantly with the quorum sensing regulated functions in C. violaceum (violacein), P. aeruginosa (elastase, pyocyanin and alginate production) and S. marcescens (prodigiosin). The complexes demonstrated potent broad-spectrum biofilm inhibition in Pseudomonas aeruginosa, E. coli, Chromobacterium violaceum, Serratia marcescens, Klebsiella pneumoniae and Listeria monocytogenes. Biofilm inhibition was visualized using SEM and CLSM images. Action of the copper(I) complexes on two key QS regulated functions contributing to biofilm formation i.e. EPS production and swarming motility was also studied and statistically significant reduction was recorded. These results could form the basis for development of safe anti-QS and anti-biofilm agents that can be utilized in the food industry as well as healthcare sector to prevent food-associated diseases.}, } @article {pmid31484626, year = {2019}, author = {Cusumano, JA and Caffrey, AR and Daffinee, KE and Luther, MK and Lopes, V and LaPlante, KL}, title = {Weak biofilm formation among carbapenem-resistant Klebsiella pneumoniae.}, journal = {Diagnostic microbiology and infectious disease}, volume = {95}, number = {4}, pages = {114877}, doi = {10.1016/j.diagmicrobio.2019.114877}, pmid = {31484626}, issn = {1879-0070}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Carbapenem-Resistant Enterobacteriaceae/drug effects/isolation & purification/*physiology ; Drug Resistance, Multiple, Bacterial ; Humans ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/drug effects/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {Biofilm formation of multidrug and extensively drug resistant Klebsiella pneumoniae isolates is poorly understood. We investigated 139 diverse clinical K. pneumoniae isolates that possess various resistance patterns to evaluate the relationship between biofilm formation and resistance. Antimicrobial resistance was compared among a diverse collection of weak versus strong biofilm-forming K. pneumoniae, and predictors of strong biofilm formation were identified. Multi-drug resistant isolates were more common among weak (97.9%) versus strong biofilm formers (76%; P = 0.002). Carbapenem-resistant K. pneumoniae were 91% less likely to form strong biofilm (odds ratio 0.09; 95% confidence interval 0.02-0.33). The statistically significant inverse relationship between biofilm formation and antibiotic resistance suggests that virulence may be a trade-off for survival.}, } @article {pmid31484288, year = {2019}, author = {Nilsson, M and Givskov, M and Twetman, S and Tolker-Nielsen, T}, title = {Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance.}, journal = {Microorganisms}, volume = {7}, number = {9}, pages = {}, pmid = {31484288}, issn = {2076-2607}, support = {DFF - 1323-00177//Natur og Univers, Det Frie Forskningsråd/ ; 11/1596//Tandlægefonden/ ; }, abstract = {Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutans pgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutans pgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutans pgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutans pgmA mutant may play a role in the increased sensitivity of S. mutans pgmA biofilms toward antibiotics.}, } @article {pmid31484093, year = {2019}, author = {Zhang, M and Yu, M and Wang, Y and He, C and Pang, J and Wu, J}, title = {Operational optimization of a three-stage nitrification moving bed biofilm reactor (NMBBR) by obtaining enriched nitrifying bacteria: Nitrifying performance, microbial community, and kinetic parameters.}, journal = {The Science of the total environment}, volume = {697}, number = {}, pages = {134101}, doi = {10.1016/j.scitotenv.2019.134101}, pmid = {31484093}, issn = {1879-1026}, mesh = {Bioreactors/*microbiology ; *Microbiota ; *Nitrification ; Waste Disposal, Fluid/*methods ; }, abstract = {A two-sludge system consisting of A[2]/O (Anaerobic Anoxic Oxic) and NMBBR (Nitrification Moving Bed Biofilm Reactor) was developed. Stable and efficient denitrifying phosphorus removal can be realized by high-efficiency utilization of carbon sources in A[2]/O reactor with the electron acceptors of NOx[-]-N in a three-stage NMBBR (consisting of N1, N2, N3). The three-stage NMBBR was successfully started within 18 days without additional inoculation sludge. Then a long-term operation (22-120 d) for the optimization of nitrifying performance, microbial community, and kinetic parameters was investigated. The biofilm characteristics (MLSS and biofilm thickness) and real-time control parameters (DO and pH) initially revealed the differences of three stages, while FISH results confirmed the optimizing nitrifying bacteria populations including AOB, Nitrobacteria and Nitrospira (N1: 5.94 ± 0.12%; N2: 8.26 ± 0.42%; N3: 10.06 ± 0.27% on day 50), basically consisting with the qPCR results (N1: 4.05%; N2: 8.04%; N3: 14.14%). The specific ammonium oxidation rate (SAOR: 3.24-10.02 mg/(gMLSS·h)) and temperature coefficient (θ: 1.008-1.011) based on temperature variation (15-35 °C) exhibited a strong resistant ability to low temperature operation. Moreover, half-saturation constants (KN,AOB, KN,NOB, KO,AOB and KO,NOB) fitted by Monod equation proved that DO diffusion played a significant role than substrate utilization (NH4[+]-N and NO2[-]-N), but the diffusion resistance was negligible for flocs size smaller than 70 μm. Additionally, the dominant NOB (mainly Nitrospira) due to a higher KN,NOB and KO,NOB was more sensitive to mass transfer and diffusion resistance, which was helpful to understand the microbial competition for short-cut nitrification between AOB and NOB. Based on the above mechanism analysis, the MBBR optimization for the design and operation was put forward.}, } @article {pmid31483869, year = {2020}, author = {Wu, M and Xu, L and Cai, Z and Huang, S and Li, Y and Lei, L and Huang, X}, title = {Disinfection of Cariogenic Pathogens in Planktonic Lifestyle, Biofilm and Carious Dentine with Antimicrobial Photodynamic Therapy.}, journal = {Photochemistry and photobiology}, volume = {96}, number = {1}, pages = {170-177}, doi = {10.1111/php.13161}, pmid = {31483869}, issn = {1751-1097}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cells, Cultured ; Dental Caries/*microbiology ; Dentin/*drug effects ; Disinfection ; Humans ; Lactobacillus acidophilus/drug effects ; Photochemotherapy/*methods ; Streptococcus mutans/drug effects ; }, abstract = {Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here, we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm and carious dentine. Mono-species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms and dentine caries were treated with 0.1 mg mL[-1] toluidine Blue O followed by irradiation with a light emission diode (λ - 635 ± 10 nm; 500 mW; 31.5 J cm[-2] ; 60 s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy (SEM). One-way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm and carious dentine (P < 0.05). For S. mutans, CHX was only bactericidal against suspension (P < 0.05), while aPDT was effective on both suspension and biofilm (P < 0.05) while not for dentin caries (P > 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient.}, } @article {pmid31482327, year = {2020}, author = {Bonsaglia, ECR and Latosinski, GS and Rossi, RS and Rossi, BF and Possebon, FS and Pantoja, JCF and Fernandes Júnior, A and Rall, VLM}, title = {Biofilm production under different atmospheres and growth media by Streptococcus agalactiae isolated from milk of cows with subclinical mastitis.}, journal = {Archives of microbiology}, volume = {202}, number = {1}, pages = {209-212}, doi = {10.1007/s00203-019-01727-8}, pmid = {31482327}, issn = {1432-072X}, mesh = {Animals ; Atmosphere ; Biofilms/*growth & development ; Cattle ; Culture Media/pharmacology ; Female ; Mastitis, Bovine/*microbiology ; Milk/*microbiology ; Streptococcus agalactiae/drug effects/*physiology ; }, abstract = {Different methods to analyze Streptococcus agalactiae biofilm formation have been investigated, but standardized protocols have not been developed. We compared S. agalactiae biofilm production among different atmospheres and growth media. Biofilm formation was studied in 32 isolates from bovine mastitis cases grown in Tryptone Soy Broth (TSB), Todd Hewitt Broth (THB), Luria Bertani Broth (LB) and Brain Heart Infusion (BHI), under two atmospheres, aerobic and 5% CO2. Regardless of the culture medium, growth under 5% CO2 resulted in a greater proportion of biofilm formation (65.63%), as compared with aerobic conditions (39.84%). Regardless of the atmosphere, the chances of biofilm formation were greater for isolates grown in TSB, as compared with THB [Odds ratio (OR) = 3.02], BHI (OR = 4.57), or LB (OR = 10.20). Thus, we suggest the use of 5% CO2 atmosphere and TSB in biofilm formation assays by Group-B streptococci (GBS) isolated from intramammary infections.}, } @article {pmid31482119, year = {2019}, author = {Wu, J and Li, F and Hu, X and Lu, J and Sun, X and Gao, J and Ling, D}, title = {Responsive Assembly of Silver Nanoclusters with a Biofilm Locally Amplified Bactericidal Effect to Enhance Treatments against Multi-Drug-Resistant Bacterial Infections.}, journal = {ACS central science}, volume = {5}, number = {8}, pages = {1366-1376}, pmid = {31482119}, issn = {2374-7943}, abstract = {Bacterial biofilms pose a major threat to public health because they are resistant to most current therapeutics. Conventional antibiotics exhibit limited penetration and weakened activity in the acidic microenvironment of a biofilm. Here, the development of biofilm-responsive nanoantibiotics (rAgNAs) composed of self-assembled silver nanoclusters and pH-sensitive charge reversal ligands, whose bactericidal activity can be selectively boosted in the biofilm microenvironment, is reported. Under neutral physiological conditions, the bactericidal activity of rAgNAs is self-quenched because the toxic silver ions' release is largely inhibited; however, upon entry into the acidic biofilm microenvironment, the rAgNAs not only exhibit charge reversal to facilitate local accumulation and retention but also disassemble into small silver nanoclusters, thus enabling deep penetration and accelerated silver ions release for dramatically amplified bactericidal activity. The superior antibiofilm activity of rAgNAs is demonstrated both in vitro and in vivo, and the mortality rate of mice with multi-drug-resistant biofilm-induced severe pyomyositis can be significantly reduced by rAgNAs treatment, indicating the immense potential of rAgNAs as highly efficient nanoscale antibacterial agents to combat resistant bacterial biofilm-associated infections.}, } @article {pmid31482007, year = {2019}, author = {Keshvardoust, P and Huron, VAA and Clemson, M and Constancias, F and Barraud, N and Rice, SA}, title = {Biofilm formation inhibition and dispersal of multi-species communities containing ammonia-oxidising bacteria.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {22}, pmid = {31482007}, issn = {2055-5008}, mesh = {Ammonium Compounds/metabolism ; Biofilms/*growth & development ; Carbon/metabolism ; Culture Media/chemistry ; *Microbial Interactions ; *Microbiota ; Nitrification ; Nitrosomonas europaea/*growth & development/metabolism ; Organic Chemicals/metabolism ; }, abstract = {Despite considerable research, the biofilm-forming capabilities of Nitrosomonas europaea are poorly understood for both mono and mixed-species communities. This study combined biofilm assays and molecular techniques to demonstrate that N. europaea makes very little biofilm on its own, and relies on the activity of associated heterotrophic bacteria to establish a biofilm. However, N. europaea has a vital role in the proliferation of mixed-species communities under carbon-limited conditions, such as in drinking water distribution systems, through the provision of organic carbon via ammonia oxidation. Results show that the addition of nitrification inhibitors to mixed-species nitrifying cultures under carbon-limited conditions disrupted biofilm formation and caused the dispersal of pre-formed biofilms. This dispersal effect was not observed when an organic carbon source, glucose, was included in the medium. Interestingly, inhibition of nitrification activity of these mixed-species biofilms in the presence of added glucose resulted in increased total biofilm formation compared to controls without the addition of nitrification inhibitors, or with only glucose added. This suggests that active AOB partially suppress or limit the overall growth of the heterotrophic bacteria. The experimental model developed here provides evidence that ammonia-oxidising bacteria (AOB) are involved in both the formation and maintenance of multi-species biofilm communities. The results demonstrate that the activity of the AOB not only support the growth and biofilm formation of heterotrophic bacteria by providing organic carbon, but also restrict and limit total biomass in mixed community systems.}, } @article {pmid31480443, year = {2019}, author = {Gabe, V and Kacergius, T and Abu-Lafi, S and Zeidan, M and Abu-Farich, B and Austys, D and Masalha, M and Rayan, A}, title = {Suppressive Effects of Octyl Gallate on Streptococcus mutans Biofilm Formation, Acidogenicity, and Gene Expression.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {17}, pages = {}, pmid = {31480443}, issn = {1420-3049}, mesh = {Acids/*metabolism ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Biomass ; Gallic Acid/*analogs & derivatives/chemistry/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Bacterial ; Glass/chemistry ; Polystyrenes/chemistry ; Streptococcus mutans/drug effects/*genetics/*physiology ; Surface Properties ; }, abstract = {The accumulation of biofilm by Streptococcus mutans bacteria on hard tooth tissues leads to dental caries, which remains one of the most prevalent oral diseases. Hence, the development of new antibiofilm agents is of critical importance. The current study reports the results from testing the effectiveness of octyl gallate (C8-OG) against: (1) S. mutans biofilm formation on solid surfaces (polystyrene, glass), (2) acidogenicity, (3) and the expression of biofilm-related genes. The amount of biofilm formed by S. mutans bacteria was evaluated using the colorimetric method and optical profilometry. The pH of the biofilm growth medium was measured with microelectrode. A quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to assess the expression of genes encoding glucan binding protein B (gbpB), glucosyltransferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of the F1 protein (atpD). The results show that C8-OG significantly diminished biofilm formation by exposed S. mutans on solid surfaces and suppressed acidogenicity in a dose-dependent manner, compared to unexposed bacteria (p < 0.05). The C8-OG concentration of 100.24 µM inhibited S. mutans biofilm development on solid surfaces by 100% and prevented a decrease in pH levels by 99%. In addition, the RT-qPCR data demonstrate that the biofilm-producing bacteria treated with C8-OG underwent a significant reduction in gene expression in the case of the four genes under study (gbpB, gtfC, gtfD, and atpD), and there was a slight decrease in expression of the gtfB gene. However, C8-OG treatments did not produce significant expression change compared to the control for the planktonic cells, although there was a significant increase for the atpD gene. Therefore, C8-OG might be a potent antibiofilm and/or anticaries agent for oral formulations that aim to reduce the prevalence of dental caries.}, } @article {pmid31479959, year = {2019}, author = {Wu, Y and Cai, P and Jing, X and Niu, X and Ji, D and Ashry, NM and Gao, C and Huang, Q}, title = {Soil biofilm formation enhances microbial community diversity and metabolic activity.}, journal = {Environment international}, volume = {132}, number = {}, pages = {105116}, doi = {10.1016/j.envint.2019.105116}, pmid = {31479959}, issn = {1873-6750}, mesh = {*Biofilms/drug effects ; Biopolymers/metabolism ; Glucose/pharmacology ; *Microbiota/genetics/physiology ; RNA, Ribosomal, 16S/genetics ; Soil ; *Soil Microbiology ; }, abstract = {Biofilms have been extensively studied in aquatic and clinical environments. However, the complexity of edaphic microenvironment hinders the advances toward understanding the environmental functionalities and ecological roles of soil biofilms. In this work, artificial soil was employed to investigate the soil biofilm formation and corresponding impacts on community structure and microbial activities. Our results showed that extracellular polymeric substances (EPS) production was significantly enhanced and micro-meter sized cell aggregates formed with high glucose amendment. Biofilm development exhibited significant effects on the soil microbial processes. 16S rRNA gene sequencing demonstrated the soils with biofilms and free-living cells shared similar microbial communities. But the Shannon diversity and evenness indices of communities with soil biofilms were significantly enhanced by 18.2% and 17.1%. The soil with biofilms also revealed a rapid response to nutrient provision and robust microbial activity, which consumed 65.4% more oxygen in the topsoil (0-1.5 mm). Kinetic respiration analysis showed that the enhanced metabolic activity was attributed to 23-times more active microbes in soil biofilms. In summary, this study revealed that soil biofilms can sustain a diverse and robust community to drive soil biogeochemical processes.}, } @article {pmid31478651, year = {2019}, author = {Dunsing, V and Irmscher, T and Barbirz, S and Chiantia, S}, title = {Purely Polysaccharide-Based Biofilm Matrix Provides Size-Selective Diffusion Barriers for Nanoparticles and Bacteriophages.}, journal = {Biomacromolecules}, volume = {20}, number = {10}, pages = {3842-3854}, doi = {10.1021/acs.biomac.9b00938}, pmid = {31478651}, issn = {1526-4602}, mesh = {Bacteriophages/*metabolism ; Biofilms ; Nanoparticles/*metabolism ; Pantoea/metabolism ; Polymers/metabolism ; Polysaccharides/*metabolism ; Polysaccharides, Bacterial/metabolism ; }, abstract = {Biofilms are complex mixtures of proteins, DNA, and polysaccharides surrounding bacterial communities as protective barriers that can be biochemically modified during the bacterial life cycle. However, their compositional heterogeneity impedes a precise analysis of the contributions of individual matrix components to the biofilm structural organization. To investigate the structural properties of glycan-based biofilms, we analyzed the diffusion dynamics of nanometer-sized objects in matrices of the megadalton-sized anionic polysaccharide, stewartan, the major biofilm component of the plant pathogen, Pantoea stewartii. Fluorescence correlation spectroscopy and single-particle tracking of nanobeads and bacteriophages indicated notable subdiffusive dynamics dependent on probe size and stewartan concentration, in contrast to free diffusion of small molecules. Stewartan enzymatic depolymerization by bacteriophage tailspike proteins rapidly restored unhindered diffusion. We, thus, hypothesize that the glycan polymer stewartan determines the major physicochemical properties of the biofilm, which acts as a selective diffusion barrier for nanometer-sized objects and can be controlled by enzymes.}, } @article {pmid31476321, year = {2019}, author = {Tao, S and He, L and Xu, HHK and Weir, MD and Fan, M and Yu, Z and Zhang, M and Zhou, X and Liang, K and Li, J}, title = {Dentin remineralization via adhesive containing amorphous calcium phosphate nanoparticles in a biofilm-challenged environment.}, journal = {Journal of dentistry}, volume = {89}, number = {}, pages = {103193}, doi = {10.1016/j.jdent.2019.103193}, pmid = {31476321}, issn = {1879-176X}, mesh = {Biofilms ; Calcium Phosphates/*pharmacology ; *Dental Cements ; Dentin/*drug effects ; Humans ; *Nanoparticles ; *Tooth Remineralization ; }, abstract = {OBJECTIVES: The remineralization of dentin at a bonded interface would help to strengthen the bonded interface and inhibit secondary caries, and would prolong the longevity of restoration. The aim of this study was to investigate the remineralization of demineralized human dentin in a dental biofilm environment via an adhesive containing nanoparticles of amorphous calcium phosphate (NACP).

METHODS: Dentin demineralization was promoted by subjecting samples to a Streptococcus mutans acidic biofilm for 24 h. Samples were divided into a control group, a commercial fluoride-releasing adhesive group, and an NACP adhesive group. All samples were subjected to a remineralization protocol consisting of 4-h exposure per 24-h period in brain heart infusion broth plus 1% sucrose (BHIS) followed by immersion in artificial saliva for the remaining period. The pH of BHIS after 4-h immersion was measured every other day. After 10 days, the biofilm was assessed for colony-forming unit (CFU) count, lactic acid production, live/dead staining, and calcium and phosphate content. The mineral changes in the demineralized dentin samples were analyzed by transverse microradiography, hardness measurement, X-ray diffraction characterization, and scanning electron microscopy.

RESULTS: The NACP adhesive achieved acid neutralization, decreased biofilm CFU count, decreased biofilm lactic acid production, and increased biofilm calcium and phosphate content (P < 0.05). The NACP adhesive group had higher remineralization value than the commercial fluoride-releasing adhesive group (P < 0.05).

CONCLUSIONS: The NACP adhesive was effective in remineralizing dentin lesions in a biofilm model. Its ability to protect bond interface, inhibit secondary caries, and prolong the longevity of restoration is promising.

CLINICAL SIGNIFICANCE: Using NACP-containing adhesives could be recommended because of the protective ability of its hybrid layer even under a biofilm-challenged environment.}, } @article {pmid31475567, year = {2020}, author = {Cheng, P and Osei-Wusu, D and Zhou, C and Wang, Y and Xu, Z and Chang, T and Huo, S}, title = {The effects of refractory pollutants in swine wastewater on the growth of Scenedesmus sp. with biofilm attached culture.}, journal = {International journal of phytoremediation}, volume = {22}, number = {3}, pages = {241-250}, doi = {10.1080/15226514.2019.1658706}, pmid = {31475567}, issn = {1549-7879}, mesh = {Animals ; Biodegradation, Environmental ; Biofilms ; Biomass ; *Environmental Pollutants ; *Microalgae ; Nitrogen ; Phosphorus ; *Scenedesmus ; Swine ; Wastewater ; }, abstract = {Microalgae have been widely used for treatment of swine wastewater. However, the research on combined treatment of refractory pollutants ammonia nitrogen, Cu (II) and antibiotics from swine wastewater was still scattered. This study, the growth and removal efficiency of NH4Cl, CuSO4, tetracycline, norfloxacin and sulfadimidine with selected Scenedsmus sp. was investigated by biofilm attached culture. The results showed that low concentration of ammonia nitrogen had little effect on algae growth. The highest biomass productivity was 6.2 g/(m[2]d) at the concentration of NH4Cl of 50.0 mg/L, which was similar to that of a standard growth medium BG 11. Cu (II) concentration of 1.0 mg/L could accelerate the growth of Scenedsmus sp., and the highest biomass was 57.2 g/m[2] in 8 days. Moreover, the highest biomass mean values was 59.5 g/m[2], 57.1 g/m[2,] and 58.1 g/m[2], respectively, when tetracycline concentration was 20.0 mg/L, norfloxacin concentration was 100.0 mg/L and sulfadimidine concentration was 10.0 mg/L. The removal efficiency of ammonia nitrogen, copper, tetracycline, norfloxacin and sulfadimidine with Scenedsmus sp. at their optimal initial concentration by biofilm attached culture was 85.2%, 64.6%, 74.6%,71.2%, and 62.3%, respectively. This study provides a theoretical basis for the purification of refractory substances from swine wastewater.}, } @article {pmid31474100, year = {2019}, author = {Aracri, FM and Cavalcanti, RMF and Guimaraes, LHS}, title = {Extracellular Tannase from Aspergillus ochraceus: Influence of the Culture Conditions on Biofilm Formation, Enzyme Production, and Application.}, journal = {Journal of microbiology and biotechnology}, volume = {29}, number = {11}, pages = {1749-1759}, doi = {10.4014/jmb.1903.03060}, pmid = {31474100}, issn = {1738-8872}, mesh = {Aspergillus ochraceus/*enzymology/growth & development ; *Biofilms/growth & development ; Carboxylic Ester Hydrolases/*metabolism ; Culture Media/chemistry ; Fermentation ; Fungal Proteins/*metabolism ; Hydrogen-Ion Concentration ; Phenols/metabolism ; Propyl Gallate/metabolism ; Sorghum/chemistry ; Surface-Active Agents/metabolism ; Tannins/metabolism ; Temperature ; Water Pollutants/metabolism ; }, abstract = {Aspergillus ochraceus biofilm, developed on an inert support, can produce tannase in Khanna medium containing 1.5% (w/v) tannic acid as the carbon source, at an initial pH of 5.0, for 72 h at 28 °C. Addition of 0.1% yeast extract increased enzyme production. The enzyme in the crude filtrate exhibited the highest activity at 30 °C and pH 6.0. At 50 °C, the half-life was 60 min and 260 min at pH 6.0. In general, addition of detergents and surfactants did not affect tannase activity significantly. Tannase has potential applications in various biotechnological processes such as the production of propyl gallate and in the treatment of tannin-rich effluents. The content of tannins and total phenolic compounds in effluents from leather treatment was reduced by 56-83% and 47-64%, respectively, after 2 h of enzyme treatment. The content of tannins and total phenolic compounds in the sorghum flour treated for 120 h with tannase were reduced by 61% and 17%, respectively. Interestingly, the same A. ochraceus biofilm was able to produce tannase for three sequential fermentative process. In conclusion, fungal biofilm is an interesting alternative to produce high levels of tannase with biotechnological potential to be applied in different industrial sectors.}, } @article {pmid31472077, year = {2021}, author = {Patry, B and Lessard, P and Vanrolleghem, PA}, title = {Nitrification in a biofilm-enhanced highly loaded aerated lagoon.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {93}, number = {1}, pages = {16-23}, doi = {10.1002/wer.1234}, pmid = {31472077}, issn = {1554-7531}, support = {CRDPJ 478745-2015//Natural Sciences and Engineering Research Council of Canada/ ; 2015-039-PR-C16//Quebec consortium for industrial bioprocess research and innovation (CRIBIQ)/ ; UL-CI111012//Bionest Technologies Inc./ ; UL-CI111011//Primodal Inc./ ; }, mesh = {Ammonia ; Biofilms ; *Bioreactors ; *Nitrification ; Nitrogen ; }, abstract = {A full-scale biofilm-enhanced aerated lagoon using fixed submerged media was monitored using automated water quality monitoring stations over the span of one year to quantify its nitrification performance. The system was operating at a high organic loading rate averaging 5.8 g total CBOD5 /m[2] of media per day (23.9 g total CBOD5 /m[3] of lagoon per day), a total ammonia nitrogen loading rate averaging 0.9 g NH4 -N/m[2] day (3.7 g NH4 -N/m[3] day), and temperatures ranging from 1.6 to 20.8°C. The system showed an extended seasonal nitrification period compared with a simulated aerated lagoon system of the same dimensions. This extension of complete nitrification with approximately 1 month was observed in the fall despite the decrease of operating temperature down to 4°C. During this maximum nitrification period, substantial denitrification occurred, and the effluent un-ionized ammonia ratio was reduced. A temporary loss of nitrification was also experienced in relation to an episode of elevated suspended solids concentration. Measured biofilm characteristics, namely the detachment dynamics and the biofilm thickness, were used to explain this temporary nitrification loss. During wintertime, a low nitrate production was still observed, suggesting year-long retention of nitrifying bacteria in the biofilm. PRACTITIONER POINTS: Nitrification in a highly loaded biofilm-enhanced aerated lagoon is mainly affected by operating temperature. Maximum nitrification is observed during the warmer months and occurs even at high organic loading rates (>5 g CBOD5 /m[2] day). Compared with a simulated suspended growth system, the biofilm-enhanced lagoon shows a significantly extended nitrification period. The extension is observed at the end of the summertime maximum nitrification period. Low amounts of nitrate still produced during winter in the biofilm-enhanced aerated lagoon suggest year-long retention of autotrophic nitrifying biomass in the biofilm. Nitrification in the biofilm-enhanced aerated lagoon is negatively impacted by the presence of important quantities of accumulated solids that resuspend when their digestion starts as temperature increases.}, } @article {pmid31470914, year = {2019}, author = {Nascimento, MM}, title = {Approaches to Modulate Biofilm Ecology.}, journal = {Dental clinics of North America}, volume = {63}, number = {4}, pages = {581-594}, pmid = {31470914}, issn = {1558-0512}, support = {K23 DE023579/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; *Dental Caries ; Humans ; *Microbiota ; }, abstract = {Dental caries is closely related to a dysbiosis of the microbial consortia of supragingival oral biofilms driven by a sugar-frequent and acidic-pH environment. The pH is a key factor affecting the homeostasis of supragingival biofilms seen in health. There is increasing interest on the ecological dynamics of the oral microbiome and how a dysbiotic microbiota can be successfully replaced by health-beneficial flora. The concept of preventing the microbial dysbiosis related to caries through modulation of sugar intake and pH has fully emerged.}, } @article {pmid31470085, year = {2020}, author = {Sahal, G and Woerdenbag, HJ and Hinrichs, WLJ and Visser, A and Tepper, PG and Quax, WJ and van der Mei, HC and Bilkay, IS}, title = {Antifungal and biofilm inhibitory effect of Cymbopogon citratus (lemongrass) essential oil on biofilm forming by Candida tropicalis isolates; an in vitro study.}, journal = {Journal of ethnopharmacology}, volume = {246}, number = {}, pages = {112188}, doi = {10.1016/j.jep.2019.112188}, pmid = {31470085}, issn = {1872-7573}, mesh = {Antifungal Agents/*pharmacology ; Biocompatible Materials ; Biofilms/*drug effects ; Candida tropicalis/*drug effects/physiology ; *Cymbopogon ; Microbial Sensitivity Tests ; Oils, Volatile/*pharmacology ; Prostheses and Implants/microbiology ; Silicone Elastomers ; }, abstract = {Cymbopogon citratus (lemongrass) essential oil has been widely used as a traditional medicine and is well known for antimicrobial properties. Therefore, it might be a potent anti-infective and biofilm inhibitive against Candida tropicalis infections. Until now, no ideal coating or cleaning method based on an essential oil has been described to prevent biofilm formation of Candida strains on silicone rubber maxillofacial prostheses, voice prostheses and medical devices susceptible to C. tropicalis infections.

AIM OF THE STUDY: To investigate the antifungal and biofilm inhibitory effects of Cymbopogon citratus oil. Clinical isolates of C. tropicalis biofilms on different biomaterials were used to study the inhibitory effect.

MATERIALS AND METHODS: The efficacy of Cymbopogon citratus, Cuminum cyminum, Citrus limon and Cinnamomum verum essential oils were compared on biofilm formation of three C. tropicalis isolates on 24 well polystyrene plates. C. citratus oil coated silicone rubber surfaces were prepared using hypromellose ointment as a vehicle. The antifungal tests to determine minimum inhibitory and minimum fungicidal concentrations were assessed by a microbroth dilution method and biofilm formation was determined by a crystal violet binding assay.

RESULTS: C. tropicalis strains formed more biofilm on hydrophobic materials than on hydrophilic glass. C. citratus oil showed a high antifungal effect against all C. tropicalis strains. For comparison, C. limon oil and C. cyminum oil showed minor to no killing effect against the C. tropicalis strains. C. citratus oil had the lowest minimal inhibitory concentration of all essential oils tested and inhibited biofilm formation of all C. tropicalis strains. C. citratus oil coating on silicone rubber resulted in a 45-76% reduction in biofilm formation of all C. tropicalis strains.

CONCLUSION: Cymbopogon citratus oil has good potential to be used as an antifungal and antibiofilm agent on silicone rubber prostheses and medical devices on which C. tropicalis biofilms pose a serious risk for skin infections and may cause a shorter lifespan of the prosthesis.}, } @article {pmid31469956, year = {2019}, author = {Zhu, C and Zhang, M and Tang, Q and Yang, Q and Li, J and He, X and Ye, Y}, title = {Structure and Activity of the Camellia oleifera Sapogenin Derivatives on Growth and Biofilm Inhibition of Staphylococcus aureus and Escherichia coli.}, journal = {Journal of agricultural and food chemistry}, volume = {67}, number = {51}, pages = {14143-14151}, doi = {10.1021/acs.jafc.9b03577}, pmid = {31469956}, issn = {1520-5118}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Camellia/*chemistry ; Escherichia coli/*drug effects/growth & development/physiology ; Microbial Sensitivity Tests ; Sapogenins/*chemistry/*pharmacology ; Seeds/chemistry ; Staphylococcus aureus/*drug effects/growth & development/physiology ; Structure-Activity Relationship ; }, abstract = {Sapogenin is the main block of Camellia oleifera saponin, which was purified and structurally modified by the C28 acylation reaction to synthesize 19 new derivatives. The growth and biofilm inhibition of Staphylococcus aureus and Escherichia coli was measured to evaluate their antibacterial effects. A three-dimensional quantitative structure-activity relationship (3D-QSAR) assay indicated that the antibacterial activities were significantly enhanced after sapogenin was modified with an aromatic ring or heterocyclic ring and electron-withdrawing substituents at the meta or para position. Among them, the derivative of sapogenin with a 2-mercapto-4-methyl-5-thiazolyl acetyl group obviously destroyed bacterial biofilm and made bacteria lysis. 3D-QSAR provides practical information for the structural design of sapogenin derivatives with strong antibacterial activity, and the C. oleifera sapogenin derivative 28-O-(2-mercapto-4-methyl-5-thiazolyl)-3β,16α,21β,22α-O-tetrahydroxy-oleantel-2-ene-23-aldehyde (S-16) is an effective candidate as an antibacterial agent for the prevention of bacterial resistance against antibiotics.}, } @article {pmid31469892, year = {2019}, author = {Perov, S and Lidor, O and Salinas, N and Golan, N and Tayeb-Fligelman, E and Deshmukh, M and Willbold, D and Landau, M}, title = {Structural Insights into Curli CsgA Cross-β Fibril Architecture Inspire Repurposing of Anti-amyloid Compounds as Anti-biofilm Agents.}, journal = {PLoS pathogens}, volume = {15}, number = {8}, pages = {e1007978}, pmid = {31469892}, issn = {1553-7374}, mesh = {Amyloid/*antagonists & inhibitors/drug effects ; Biofilms/drug effects/*growth & development ; Crystallography, X-Ray ; Escherichia coli Proteins/*chemistry/*metabolism ; Humans ; Microscopy, Electron, Transmission ; Peptide Fragments/chemistry/*pharmacology ; Protein Binding ; Salmonella typhimurium/drug effects/physiology ; }, abstract = {Curli amyloid fibrils secreted by Enterobacteriaceae mediate host cell adhesion and contribute to biofilm formation, thereby promoting bacterial resistance to environmental stressors. Here, we present crystal structures of amyloid-forming segments from the major curli subunit, CsgA, revealing steric zipper fibrils of tightly mated β-sheets, demonstrating a structural link between curli and human pathological amyloids. D-enantiomeric peptides, originally developed to interfere with Alzheimer's disease-associated amyloid-β, inhibited CsgA fibrillation and reduced biofilm formation in Salmonella typhimurium. Moreover, as previously shown, CsgA fibrils cross-seeded fibrillation of amyloid-β, providing support for the proposed structural resemblance and potential for cross-species amyloid interactions. The presented findings provide structural insights into amyloidogenic regions important for curli formation, suggest a novel strategy for disrupting amyloid-structured biofilms, and hypothesize on the formation of self-propagating prion-like species originating from a microbial source that could influence neurodegenerative diseases.}, } @article {pmid31469013, year = {2019}, author = {Sidrim, JJ and Amando, BR and Gomes, FI and do Amaral, MS and de Sousa, PC and Ocadaque, CJ and Brilhante, RS and A Cordeiro, R and Rocha, MF and Scm Castelo-Branco, D}, title = {Chlorpromazine-impregnated catheters as a potential strategy to control biofilm-associated urinary tract infections.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {1023-1034}, doi = {10.2217/fmb-2019-0092}, pmid = {31469013}, issn = {1746-0921}, mesh = {Anti-Infective Agents/*administration & dosage ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/*prevention & control ; Chlorpromazine/*administration & dosage ; Enterobacteriaceae Infections/*prevention & control ; Escherichia coli/drug effects/growth & development ; Humans ; Klebsiella pneumoniae/drug effects/growth & development ; Microbial Sensitivity Tests ; Proteus mirabilis/drug effects/growth & development ; Urinary Catheterization/*methods ; Urinary Tract Infections/*prevention & control ; }, abstract = {Aim: This study proposes the impregnation of Foley catheters with chlorpromazine (CPZ) to control biofilm formation by Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae. Materials & methods: The minimum inhibitory concentrations (MICs) for CPZ and the effect of CPZ on biofilm formation were assessed. Afterward, biofilm formation and the effect of ciprofloxacin and meropenem (at MIC) on mature biofilms grown on CPZ-impregnated catheters were evaluated. Results: CPZ MIC range was 39.06-625 mg/l. CPZ significantly reduced (p < 0.05) biofilm formation in vitro and on impregnated catheters. In addition, CPZ-impregnation potentiated the antibiofilm activity of ciprofloxacin and meropenem. Conclusion: These findings bring perspectives for the use of CPZ as an adjuvant for preventing and treating catheter-associated urinary tract infections.}, } @article {pmid31468360, year = {2020}, author = {Cacaci, M and Martini, C and Guarino, C and Torelli, R and Bugli, F and Sanguinetti, M}, title = {Graphene Oxide Coatings as Tools to Prevent Microbial Biofilm Formation on Medical Device.}, journal = {Advances in experimental medicine and biology}, volume = {1282}, number = {}, pages = {21-35}, doi = {10.1007/5584_2019_434}, pmid = {31468360}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*pharmacology ; Equipment and Supplies/*microbiology ; Graphite/*pharmacology ; Humans ; }, abstract = {The clinical challenge on surface engineering of medical devices to prevent microorganisms adhesion and biofilm formation, has become an essential aspect for medical implants. Antibacterial properties of Graphene Oxide (GO) have been demonstrated across a broad spectrum of bacteria, and the different mechanisms of action with which this nanomaterial interacts with the microbial surface have been elucidated in detail. Innovative protective coatings based on graphene film and hydrogel could represent an innovative solution for the prevention of nosocomial pathogens colonization on implantable device. This brief review mainly focuses on the applications of graphene in nanomedicine with a particular deepening on the antibacterial properties of GO and GO-based nanomaterials. In order to evaluate the possible future applications of GO as an anti-biofilm coating material for medical devices, studies on the ability of graphene coated surface to prevent microbial adhesion are also discussed. A concise review on in vitro toxicity and in vivo safety is also presented.}, } @article {pmid31468316, year = {2019}, author = {Vuotto, C and Donelli, G}, title = {Novel Treatment Strategies for Biofilm-Based Infections.}, journal = {Drugs}, volume = {79}, number = {15}, pages = {1635-1655}, pmid = {31468316}, issn = {1179-1950}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; Infections/*drug therapy ; }, abstract = {Biofilm-growing cells show an enhanced antimicrobial tolerance with respect to the same cells growing in a free-floating way. This is due to physical or chemical diffusion barriers and increased transfer of resistance markers. Thus, tissue- and medical device-related biofilms can be considered among the leading sources of antibiotic treatment failure, causing many of the deadliest chronic infections afflicting humans nowadays. To find a satisfying way to counteract this major health threat, a great effort has been made in recent years to develop safe, effective and fast-acting anti-biofilm strategies. In this review, we summarise and evaluate the most promising tools and molecules that have demonstrated their ability to modulate steps involved in biofilm formation or to disperse pre-formed biofilms, without conferring evolutionary pressure to microorganisms.}, } @article {pmid31467861, year = {2019}, author = {Heuschkel, I and Hoschek, A and Schmid, A and Bühler, B and Karande, R and Bühler, K}, title = {Mixed-trophies biofilm cultivation in capillary reactors.}, journal = {MethodsX}, volume = {6}, number = {}, pages = {1822-1831}, pmid = {31467861}, issn = {2215-0161}, abstract = {The biocatalytic application of photoautotrophic organisms is a promising alternative for the production of biofuels and value-added compounds as they do not rely on carbohydrates as a source of carbon, electrons, and energy. Although the photoautotrophic organisms hold potential for the development of sustainable processes, suitable reactor concepts that allow high cell density (HCD) cultivation of photoautotrophic microorganisms are limited. Such reactors need a high surface to volume ratio to enhance light availability. Furthermore, the accumulation of high oxygen concentrations as a consequence of oxygenic photosynthesis, and its inhibitory effect on cell growth needs to be prevented. Here, we present a method for HCD cultivation of oxygenic phototrophs based on the co-cultivation of different trophies in a biofilm format to avoid high oxygen partial-pressure and attain HCDs of up to 51.8 gBDW L[-1] on a lab scale. In this article, we show: •A robust method for mixed trophies biofilm cultivation in capillary reactors•Set-up and operation of a biofilm capillary reactor•A method to quantify oxygen in the continuous biofilm capillary reactor.}, } @article {pmid31467830, year = {2019}, author = {Gozoua, E and Koffi-Nevry, R and Blache, Y}, title = {Biofilm formation in marine bacteria and biocidal sensitivity: interplay between a potent antibiofilm compound (AS162) and quorum-sensing autoinducers.}, journal = {3 Biotech}, volume = {9}, number = {9}, pages = {338}, pmid = {31467830}, issn = {2190-572X}, abstract = {The capacity of two homoserine lactones to stimulate the marine bacteria Pseudoalteromonas ulvae (TC14 strain) for its capacity to form a biofilm when exposed to a potent antibiofilm compound AS162 is reported. Effective concentrations (EC50) of AS162 at 24 h, 48 h, and 72 h were, respectively, of 4.3, 4.4, and 6.0 µM. When tested in combination with HSLs, results showed that quorum-sensing signal molecules 3-oxo-C6 and 3-oxo-C8 homoserine lactones do not act directly on the biofilm formation, but are able to interfere positively with AS162 to promote biofilm growth with EC50 ranging from 30 to 50 µM. The same results were obtained with two other marine bacterial strains: Pseudoalteromonas lipolytica TC8 and Paracoccus sp. 4M6. These findings suggest that HSLs can significantly affect the biocidal sensitivity of marine bacteria to antifouling agents.}, } @article {pmid31466323, year = {2019}, author = {Senpuku, H and Nakamura, T and Iwabuchi, Y and Hirayama, S and Nakao, R and Ohnishi, M}, title = {Effects of Complex DNA and MVs with GTF Extracted from Streptococcus mutans on the Oral Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {17}, pages = {}, pmid = {31466323}, issn = {1420-3049}, support = {21390506, 24659821, 16K11537//Japan Society for the Promotion of Science/ ; 40105502//Japan Agency for Medical Research and Development/ ; }, mesh = {Adult ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cell Line ; Cytoplasmic Vesicles/*metabolism ; DNA, Bacterial/*genetics ; Glucosyltransferases/genetics ; Healthy Volunteers ; Humans ; Middle Aged ; Mutation ; Saliva/microbiology ; Streptococcus mutans/genetics/*physiology ; }, abstract = {Streptococcus mutans is one of the principal pathogens for the development of dental caries. Oral biofilms formed by S. mutans are constructed of insoluble glucan formation induced by the principal enzymes, GTF-I and GTF-SI, in sucrose-containing conditions. However, as another means of biofilm formation, extracellular DNA (eDNA) and membrane vesicles (MVs) are also contributors. To explore the roles of eDNA and MVs for biofilm formation, short and whole size pure DNAs, two types of sub-purified DNAs and MVs were extracted from S. mutans by beads destruction, treatment of proteinase K, and ultracentrifugation of culture supernatant, and applied into the biofilm formation assay using the S. mutans UA159 gtfBC mutant, which lost GTF-I and GTF-SI, on a human saliva-coated 96 well microtiter plate in sucrose-containing conditions. Sub-purified DNAs after cell lysis by beads destruction for total 90 and 180 s showed a complex form of short-size DNA with various proteins and MVs associated with GTF-I and GTF-SI, and induced significantly higher biofilm formation of the S. mutans UA159.gtfBC mutant than no sample (p < 0.05). Short-size pure DNA without proteins induced biofilm formation but whole-size pure DNA did not. Moreover, the complex form of MV associated with GTFs and short-size DNA showed significantly higher biofilm formation of initial colonizers on the human tooth surface such as Streptococcus mitis than no sample (p < 0.05). The short-size DNAs associated with MVs and GTFs are important contributors to the biofilm formation and may be one of additional targets for the prevention of oral biofilm-associated diseases.}, } @article {pmid31466002, year = {2020}, author = {Herath, BS and Sathasivan, A}, title = {The chloramine stress induces the production of chloramine decaying proteins by microbes in biomass (biofilm).}, journal = {Chemosphere}, volume = {238}, number = {}, pages = {124526}, doi = {10.1016/j.chemosphere.2019.124526}, pmid = {31466002}, issn = {1879-1298}, mesh = {Ammonia/metabolism ; *Biofilms/drug effects ; *Biomass ; Bioreactors/*microbiology ; Chloramines/*metabolism/*pharmacology ; Disinfectants/pharmacology ; Nitrification ; Proteins/*metabolism ; Stress, Physiological/*drug effects ; }, abstract = {In this paper, for the first time, we show in chloraminated systems, the chloramine decaying proteins (CDP) play an important role in bulk water and biomass (biofilm) in resisting disinfectant. Extracellular polymeric substances in biofilm/biomass are known to protect microbes from disinfectants and toxic materials, but the exact mechanism(s) is/are not known. Starting with the seed from a nitrifying chloraminated reactor, two 5 L reactors were fed intermittently with either chloramine or ammonia containing nutrient solution. The degree of nitrification increased with time in both reactors despite an increase in soluble CDP in the chloraminated reactor, while soluble CDP decreased in the ammoniated one. The suspended biomass collected after eight months of operation from chloraminated reactor contained CDP and responded to short-term chloramine stress (1.5 h with initial 1.5 mg-Cl2·L[-1]) by the additional production of soluble CDP. The suspended biomass from ammoniated reactor neither contained CDP nor produced soluble CDP as a stress response. The production, release and accumulation of CDP in biomass (biofilm) could be one of several mechanisms microbes use to defend against disinfectants (stress). The new understanding will pave the way for better disinfection management and better design of experiments.}, } @article {pmid31465921, year = {2019}, author = {Fan, X and Peng, P and Huang, H and Peng, C and Gao, Y and Ren, H}, title = {Undesirable effects of exogenous N-acyl homoserine lactones on moving bed biofilm reactor treating medium-strength synthetic wastewater.}, journal = {The Science of the total environment}, volume = {696}, number = {}, pages = {134061}, doi = {10.1016/j.scitotenv.2019.134061}, pmid = {31465921}, issn = {1879-1026}, mesh = {4-Butyrolactone/analogs & derivatives ; *Acyl-Butyrolactones ; *Biofilms ; *Bioreactors ; Homoserine/analogs & derivatives ; Lactones ; *Waste Disposal, Fluid ; }, abstract = {Exogenous AHLs are gradually reported to facilitate biofilm growth, however, whether they play a universal role in promoting biofilm formation and pollutants removal remains to be investigated. The pollutant removal, biofilm properties, microbial community and the distribution of AHLs were investigated in three lab-scale MBBRs by continuous dosing 100 nM N-Hexanoyl-L-homoserine lactone (C6-HSL) and N-Octanoyl-L-homoserine lactone (C8-HSL) in synthetic wastewater under normal nutrition (40 mg/L NH4[+]-N with C/N = 20). Results showed that adding AHLs didn't affect organics removal and exogenous C6-HSL even significantly suppressed NH4[+]-N removal by 0.44-20.29% after 16 days (p < 0.05). The introduction of AHLs both facilitated biofilm growth and extracellular polymeric substances secretion while suppressed ATP production especially during the stable operation period, with 48.96% by C6-HSL (p < 0.05) and 27.25% by C8-HSL, respectively. Exogenous AHLs inhibited the proliferation of Chryseobacterium, resulting in improvement in biofilm growth and it probably mediated ATP synthesis through regulating the release of 3OHC12-HSL in aqueous phase. Organics removal and biofilm growth were mainly attributed to the combined actions of multitudinous AHLs in biofilm phase rather than that in aqueous phase. The counterintuitive conclusions obtained in this study highlighted the importance of legitimately applying exogenous AHLs to accelerate biofilm formation and the start-up of MBBR in wastewater treatment.}, } @article {pmid31464096, year = {2019}, author = {Hong, L and Liu, X and Tan, L and Cui, Z and Yang, X and Liang, Y and Li, Z and Zhu, S and Zheng, Y and Yeung, KWK and Jing, D and Zheng, D and Wang, X and Wu, S}, title = {Rapid Biofilm Elimination on Bone Implants Using Near-Infrared-Activated Inorganic Semiconductor Heterostructures.}, journal = {Advanced healthcare materials}, volume = {8}, number = {19}, pages = {e1900835}, doi = {10.1002/adhm.201900835}, pmid = {31464096}, issn = {2192-2659}, support = {51671081//NSFC/International ; 51871162//NSFC/International ; 51801056//NSFC/International ; 2016YFC1100600//National Key Research and Development Program of China/International ; 2016YFC1100604//National Key Research and Development Program of China/International ; 2018CFA064)//Natural Science Fund of Hubei Province/International ; }, mesh = {3T3 Cells ; Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cell Survival ; Escherichia coli/drug effects ; Inflammation ; Inorganic Chemicals/*chemistry ; Materials Testing ; Mice ; Nanoparticles/chemistry ; Nanotubes/chemistry ; Orthopedics ; Prostheses and Implants ; *Prosthesis Design ; Prosthesis-Related Infections/prevention & control ; *Semiconductors ; Staphylococcus aureus/drug effects ; Static Electricity ; Titanium/chemistry ; }, abstract = {Bacterial infections often cause orthopedic surgery failures. It is hard for the immune system and antibiotics to clear bacteria adhered to implants after they form a mature biofilm, and a secondary surgery is required to remove the infected implants. To avoid this, a hybrid coating of Bi2 S3 @Ag3 PO4 /Ti is prepared to eliminate biofilm using near-infrared (NIR) light. Bi2 S3 nanorod (NR) arrays are prepared on titanium (Ti) implants through hydrothermal methods, and Ag3 PO4 nanoparticles (NPs) are loaded on Bi2 S3 NR arrays using a stepwise electrostatic adsorption strategy. The introduction of Ag3 PO4 NPs enhances the photocatalysis performances of Bi2 S3 , and the hybrid coating also exhibits good photothermal effects. After 808 nm light irradiation for 15 min, it shows superior bactericidal efficiency of 99.45% against Staphylococcus aureus, 99.74% against Escherichia coli in vitro, and 94.54% against S. aureus biofilm in vivo. Bi2 S3 @Ag3 PO4 /Ti also shows good cell viability compared to pure Ti. This NIR-activated-inorganic hybrid semiconductor heterojunction coating is biocompatible and could be employed to eliminate biofilm effectively, which makes it a very promising strategy for the surface modification of bone implant materials.}, } @article {pmid31463386, year = {2019}, author = {Gebreyohannes, G and Nyerere, A and Bii, C and Sbhatu, DB}, title = {Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms.}, journal = {Heliyon}, volume = {5}, number = {8}, pages = {e02192}, pmid = {31463386}, issn = {2405-8440}, abstract = {BACKGROUND: Biofilms are multicellular communities of microorganisms held together by a self-produced extracellular matrix. The ability of microbes to form biofilm is a universal, ubiquitous, and dynamic process. This dynamic process of biofilms establishes an important strategy to withstand and survive harsh environmental conditions and antimicrobial agents.

OBJECTIVE: This review paper aims to give an overview of antibiotic resistance, intervention, and treatment of infections caused by biofilm-forming organisms. Moreover, it can also help to motivate scholars to search for new anti-biofilm strategies and most appropriate methods to tackle the effect of biofilm infections on healthcare services.

METHODS: This paper was written by reviewing recent research and review articles which are reporting about the antibiotic resistance, prevention, and treatment of biofilm-producing organisms.

CONCLUSION: Bioprospecting for quorum quenching compounds can be an appropriate solution for controlling biofilm infections.}, } @article {pmid31461929, year = {2019}, author = {Zhang, B and Zhuang, X and Guo, L and McLean, RJC and Chu, W}, title = {Recombinant N-acyl homoserine lactone-Lactonase AiiAQSI-1 Attenuates Aeromonas hydrophila Virulence Factors, Biofilm Formation and Reduces Mortality in Crucian Carp.}, journal = {Marine drugs}, volume = {17}, number = {9}, pages = {}, pmid = {31461929}, issn = {1660-3397}, support = {31672676//National Natural Science Foundation of China/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; }, mesh = {4-Butyrolactone/analogs & derivatives/antagonists & inhibitors ; Administration, Oral ; Aeromonas hydrophila/*drug effects/pathogenicity ; Animal Feed ; Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacterial Proteins/genetics/isolation & purification/*pharmacology ; Biofilms/drug effects ; Carps/microbiology ; Cell Line ; Cloning, Molecular ; Fish Diseases/*drug therapy/microbiology ; Fisheries ; Gram-Negative Bacterial Infections/drug therapy/microbiology/*veterinary ; Metalloendopeptidases/genetics/isolation & purification/*pharmacology ; Quorum Sensing/drug effects ; Recombinant Proteins/genetics/isolation & purification/pharmacology ; Virulence Factors/antagonists & inhibitors ; }, abstract = {Quorum quenching (QQ) is a promising alternative infection-control strategy to antibiotics that controls quorum-regulated virulence without killing the pathogens. Aeromonas hydrophila is an opportunistic gram-negative pathogen living in freshwater and marine environments. A. hydrophila possesses an N-acyl homoserine lactone (AHL)-based quorum-sensing (QS) system that regulates virulence, so quorum signal-inactivation (i.e., QQ) may represent a new way to combat A. hydrophila infection. In this study, an AHL lactonase gene, aiiA was cloned from Bacillus sp. strain QSI-1 and expressed in Escherichia coli strain BL21(DE3). The A. hydrophila hexanoyl homoserine lactone (C6-HSL) QS signal molecule was degraded by AiiAQSI-1, which resulted in a decrease of bacterial swimming motility, reduction of extracellular protease and hemolysin virulence factors, and inhibited the biofilm formation of A. hydrophila YJ-1 in a microtiter assay. In cell culture studies, AiiAQSI-1 decreased the ability of A. hydrophila adherence to and internalization by Epithelioma papulosum cyprini (EPC) cells. During in vivo studies, oral administration of AiiAQSI-1 via feed supplementation attenuated A. hydrophila infection in Crucian Carp. Results from this work indicate that feed supplementation with AiiAQSI-1 protein has potential to control A. hydrophila aquaculture disease via QQ.}, } @article {pmid31459295, year = {2018}, author = {Gupta, P and Gupta, S and Sharma, M and Kumar, N and Pruthi, V and Poluri, KM}, title = {Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates.}, journal = {ACS omega}, volume = {3}, number = {9}, pages = {12201-12214}, pmid = {31459295}, issn = {2470-1343}, abstract = {Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL[-1], respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter (CDR1) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase (FKS1), GPI-anchored protein (KRE1), and sterol importer (AUS1) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.}, } @article {pmid31456753, year = {2019}, author = {Zago, PMW and Dos Santos Castelo Branco, SJ and de Albuquerque Bogéa Fecury, L and Carvalho, LT and Rocha, CQ and Madeira, PLB and de Sousa, EM and de Siqueira, FSF and Paschoal, MAB and Diniz, RS and Gonçalves, LM}, title = {Anti-biofilm Action of Chenopodium ambrosioides Extract, Cytotoxic Potential and Effects on Acrylic Denture Surface.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1724}, pmid = {31456753}, issn = {1664-302X}, abstract = {Considering the challenge to control Candida-associated denture stomatitis, the search for antifungal substances derived from natural sources has become a trend in the literature. In this study the following effects of Chenopodium ambrosioides extract (CAE) were investigated: action against biofilms of Candida albicans, its cytotoxic potential, and changes caused in acrylic resin. The CAE was characterized by High Performance Liquid Chromatography (HPLC). The susceptibility of C. albicans to CAE was investigated by Minimum Inhibitory Concentration and Minimum Fungicidal Concentration (MIC and MFC) tests. Acrylic resin disks were fabricated, and C. albicans biofilms were developed on these for 48 h. Afterward the disks were immersed for 10 min in: PBS (Negative Control); 1% Sodium Hypochlorite (1% SH, Positive Control) or CAE at MIC or 5xMIC. The biofilms were investigated relative to counts and metabolic activity. The cytotoxic potential in keratinocytes and fibroblasts was verified by MTT test. Change in color and roughness of the acrylic resin was analyzed after 28 days of immersion in CAE. The data were analyzed by the ANOVA considering a 5% level of significance. The main compounds detected by HPLC were kaempferol and quercetin. Both MIC and MFC obtained the value of 0.25 mg/mL. The MIC was sufficient to significantly reduce the counts and activity of the biofilm cells (p < 0.0001), while 5xMIC resulted in almost complete eradication, similar to 1% SH. Keratinocytes and fibroblasts exposed to the MIC and 5xMIC presented cell viability similar to that of the Control Group (p > 0.05). No important changes in acrylic resin color and roughness were detected, even after 28 days. It could be concluded that the immersion of acrylic resin in C. ambrosioides extract in its minimum inhibitory concentration was effective for the reduction of C. albicans biofilms without any evidence of cytotoxic effects or changes in roughness and color of this substrate.}, } @article {pmid31456169, year = {2019}, author = {Andre, C and de Jesus Pimentel-Filho, N and de Almeida Costa, PM and Vanetti, MCD}, title = {Changes in the composition and architecture of staphylococcal biofilm by nisin.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {50}, number = {4}, pages = {1083-1090}, pmid = {31456169}, issn = {1678-4405}, support = {APQ 02600-14-1//FAPEMIG/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Extracellular Matrix/drug effects/metabolism ; Microscopy, Confocal ; Nisin/*pharmacology ; Staphylococcus aureus/cytology/*drug effects/genetics/physiology ; Staphylococcus epidermidis/cytology/*drug effects/genetics/physiology ; }, abstract = {Bacterial biofilms are involved in various medical infections and food contamination episodes and, for this reason, it is of great importance to developing new strategies of its prevention and control. The subinhibitory concentration of nisin was determined, and its effect against Staphylococcus aureus and Staphylococcus epidermidis biofilms was evaluated. Results obtained by confocal laser microscopy demonstrated morphological changes in the architecture of the structure of biofilms. The main components (polysaccharides, proteins, and extracellular DNA (eDNA)) of the biofilm matrix were determined by spectrophotometry and showed that the formation of staphylococcal biofilms in the presence of nisin results in a less dense matrix structure with modification in its constituents. These results contribute to increase the knowledge of the composition and architecture of the extracellular matrix of biofilms of S. aureus, as well as evidence that the investigation of alternative products to assist in the control and combat of biofilms is a promising strategy.}, } @article {pmid31454730, year = {2019}, author = {Zhou, H and Xu, G}, title = {Integrated effects of temperature and COD/N on an up-flow anaerobic filter-biological aerated filter: Performance, biofilm characteristics and microbial community.}, journal = {Bioresource technology}, volume = {293}, number = {}, pages = {122004}, doi = {10.1016/j.biortech.2019.122004}, pmid = {31454730}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Extracellular Polymeric Substance Matrix ; *Microbiota ; Nitrogen ; Temperature ; }, abstract = {The integrated effects of temperature and COD/N ratio on performance, biofilm characteristics and microbial community in up-flow anaerobic filter-biological aerated filters (UAF-BAFs) were investigated. Results indicated that the UAF-BAF system could achieve excellent COD, NH4[+]-N and TN removal, in which effluent quality well met the Class 1A standard. Biofilm physicochemical characteristics showed that the biomass, biofilm thickness and extracellular polymeric substance (EPS) content in the UAF-BAFs reduced with the decrease in COD/N ratio, but were enhanced under low temperature. The biofilm structure characterized by CLSM in the UAF-BAFs significantly shifted, which was closely correlated with operational conditions. Sequencing analysis revealed that Proteobacteria, Epsilonbacteraeota, Bacteroidetes and Firmicutes were dominant in the UAFs and the abundance of ammonium oxidizing bacteria (AOB) was responsible for nitrification performance in the BAFs. Functions analysis indicated that amino acid metabolism, carbohydrate metabolism, energy metabolism and lipid metabolism were clearly regulated by parameters changes.}, } @article {pmid31454717, year = {2020}, author = {Chen, LH and Li, Y and Qi, Y and Wang, SN and Gao, CQ and Wu, Y}, title = {Evaluation of a pulsed xenon ultraviolet light device for reduction of pathogens with biofilm-forming ability and impact on environmental bioburden in clinical laboratories.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {29}, number = {}, pages = {101544}, doi = {10.1016/j.pdpdt.2019.08.026}, pmid = {31454717}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Cross Infection/prevention & control ; Disinfection/*methods ; Geobacillus stearothermophilus/drug effects ; Humans ; Klebsiella pneumoniae/drug effects ; Laboratories, Hospital/*standards ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; *Ultraviolet Rays ; Xenon/*administration & dosage ; }, abstract = {BACKGROUND: Biofilm-forming organisms can persist on surfaces in hospital clinical laboratories and potentially lead to nosocomial infections. Therefore, effective decontamination procedures are essential for reducing infections. In this study, we investigated an alternative to often ineffective manual cleaning methods, a pulsed xenon ultraviolet (PX-UV) light device. We evaluated PX-UV effect on biofilm formation ability of pathogens and also evaluated PX-UV effectiveness on environmental bioburden in clinical laboratories.

METHODS: We selected and identified P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 from clinic isolates. Biofilm-forming ability and effectiveness of PX-UV in killing these biofilm forming strains on surfaces was evaluated. The central laboratory, the clinical microbiology laboratory, and the clinical immunology laboratory were chosen for testing environmental bioburden. Air samples and high-touch surface specimens in the three laboratories were obtained before and after routine manual cleaning, and after 6 min of PX-UV disinfection. The cultured microbes were then identified with MALDI- TOF-MS.

RESULTS: We found that P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 were able to form robust biofilms, and that PX-UV significantly reduced colony counts of these strains on all surfaces tested. PX-UV reduced the bioburden of air samples and eliminated bioburden on surfaces. All microbes identified in the clinical laboratories were pathogenic and consisted of cocci, rods, and fungi.

CONCLUSIONS: The PX-UV device effectively reduced pathogens with biofilm-forming ability on surfaces, and the environmental bioburden was also significantly reduced by PX-UV. PX-UV is a viable option for protecting staff and decreasing rates of laboratory-acquired infections.}, } @article {pmid31454558, year = {2019}, author = {Prasath, KG and Sethupathy, S and Pandian, SK}, title = {Proteomic analysis uncovers the modulation of ergosterol, sphingolipid and oxidative stress pathway by myristic acid impeding biofilm and virulence in Candida albicans.}, journal = {Journal of proteomics}, volume = {208}, number = {}, pages = {103503}, doi = {10.1016/j.jprot.2019.103503}, pmid = {31454558}, issn = {1876-7737}, mesh = {Biofilms/*drug effects/growth & development ; *Candida albicans/pathogenicity/physiology ; Ergosterol/*biosynthesis ; Fungal Proteins/*metabolism ; Hyphae/metabolism ; Myristic Acid/*pharmacology ; Oxidative Stress/*drug effects ; *Proteomics ; Sphingolipids/*biosynthesis ; }, abstract = {Candida albicans, a dimorphic opportunistic fungus is known to form robust biofilm and commonly associated with superficial and life threatening systemic infections. The repertoire of C. albicans infection is comprehensive due to its biofilm mediated virulence and occurrence of resistance against conventional antifungal drugs. Natural bioactive compounds are known for their antivirulence potency against fungi circumventing their resistance. In the present study, antibiofilm and antihyphal efficacies of myristic acid (MA), a major component of Myristica fragrans against C. albicans was assessed. Results of biofilm assays, optical microscopic analyses showed the potent inhibition of biofilm and hyphal formation by MA at 125 μg mL[-1]. Proteomic analysis revealed the ability of MA to target proteins involved in various virulence pathways such as ergosterol synthesis, sphingolipid metabolism, multidrug resistance and the oxidative stress. The results of gene expression analysis and biochemical assays validated the outcomes of proteomic analysis. This investigation emphasized the potent antibiofilm and virulence inhibitory potentials of MA. Hence, MA could be clinically utilized to control infections caused by C. albicans. BIOLOGICAL SIGNIFICANCE: The conventional antifungal drugs acquire single target pattern by regulating either sterol synthesis or drug efflux pump in C. albicans that ushers drug-resistance. But Myristic acid attenuates C. albicans virulence by negative regulation of proteins involved in sterol synthesis & uptake, sphingolipids and antioxidant activity. In the current study, the multi-target efficacy and the ability to inhibit biofilm and hyphae mediated virulence factors without affecting the cellular metabolism of C. albicans marks myristic acid as a potent anti-candida agent against drug resistant Candida species.}, } @article {pmid31453776, year = {2019}, author = {Henriques, M and Rodrigues, CF}, title = {Alternatives Approaches to Treat Biofilm's Infections.}, journal = {Current medicinal chemistry}, volume = {26}, number = {14}, pages = {2514}, doi = {10.2174/092986732614190724161847}, pmid = {31453776}, issn = {1875-533X}, mesh = {Bacteria/drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects ; Humans ; }, } @article {pmid31452954, year = {2019}, author = {Barkarmo, S and Longhorn, D and Leer, K and Johansson, CB and Stenport, V and Franco-Tabares, S and Kuehne, SA and Sammons, R}, title = {Biofilm formation on polyetheretherketone and titanium surfaces.}, journal = {Clinical and experimental dental research}, volume = {5}, number = {4}, pages = {427-437}, pmid = {31452954}, issn = {2057-4347}, mesh = {Bacterial Adhesion ; Benzophenones ; Biofilms/*growth & development ; Dental Abutments/*microbiology ; Enterococcus faecalis/isolation & purification ; Ketones/*chemistry ; Materials Testing ; Microscopy, Electron, Scanning ; Polyethylene Glycols/*chemistry ; Polymers ; Prosthodontics/*instrumentation ; Streptococcus gordonii/isolation & purification ; Streptococcus oralis/isolation & purification ; Streptococcus sanguis/isolation & purification ; Surface Properties ; Titanium/*chemistry ; }, abstract = {OBJECTIVE: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V).

MATERIAL AND METHODS: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet.

RESULTS: Roughness and contact angle results showed blasted PEEK > PEEK > cp-Ti = Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups.

CONCLUSION: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material.}, } @article {pmid31452924, year = {2019}, author = {McCall, AD and Pathirana, RU and Prabhakar, A and Cullen, PJ and Edgerton, M}, title = {Candida albicans biofilm development is governed by cooperative attachment and adhesion maintenance proteins.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {21}, pmid = {31452924}, issn = {2055-5008}, support = {F31 DE024346/DE/NIDCR NIH HHS/United States ; R01 DE010641/DE/NIDCR NIH HHS/United States ; R01 DE022720/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/genetics/*growth & development ; *Cell Adhesion ; Fungal Proteins/genetics/*metabolism ; Gene Deletion ; Gene Expression ; Microfluidics ; Optical Imaging ; }, abstract = {The opportunistic fungal pathogen Candida albicans is capable of adhering to the oral mucosa despite forces created by salivary flow. Although many fungal adhesion proteins have been identified, less is known about the temporal development of cell adhesion and biofilm growth in a flow environment. In this study, we use a flow system with real-time imaging of C. albicans cells as they adhere and grow. Rates of cell attachment and dispersion of C. albicans knockout strains of putative adhesins, transcription factors, and deletions with a hyperfilamentous phenotype were quantified during 18 h of biofilm development. Cell adhesion under flow is a multi-phase process initiated with cell rolling, then an initial firm attachment to the substrate occurs. After attachment, cells enter a growth phase where cells either commit to adherence or disperse. C. albicans Δeap1, Δhwp2, Δhyr1, and Δihd1 cells had significantly reduced initial attachment and subsequent adhesion, while Δals1/Δals3 had no change in initial attachment but reduced adhesion maintenance. WT cells had increased adhesion during the late growth phase when hyphae were more highly expressed. Hyperfilamentous strains had 10-fold higher total biofilm growth, a result of significantly reduced detachment rates, showing that hyphal morphogenesis is important for adhesion maintenance in the developing biofilm. The rate of C. albicans biomass dispersion was most important for determining the density of the mature biomass. Adhesion maintenance was mediated in part by Ywp1, a protein previously thought to regulate dispersion, thus it functions as an adhesion maintenance protein in C. albicans.}, } @article {pmid31451500, year = {2019}, author = {Rodríguez-Sevilla, G and Crabbé, A and García-Coca, M and Aguilera-Correa, JJ and Esteban, J and Pérez-Jorge, C}, title = {Antimicrobial Treatment Provides a Competitive Advantage to Mycobacterium abscessus in a Dual-Species Biofilm with Pseudomonas aeruginosa.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {11}, pages = {}, pmid = {31451500}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cystic Fibrosis/drug therapy/microbiology ; Humans ; Microbial Sensitivity Tests/methods ; Mycobacterium abscessus/*drug effects ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects ; Sputum/microbiology ; }, abstract = {The physiological factors that contribute to Mycobacterium abscessus lung infections remain unclear. We determined whether antibiotic treatment targeting a major cystic fibrosis pathogen (i.e., Pseudomonas aeruginosa) could provide the ideal conditions for the establishment of M. abscessus infection. Our data showed that P. aeruginosa inhibited M. abscessus biofilm formation under control conditions and that antimicrobial therapy selectively targeting P. aeruginosa diminished this competitive interaction, thereby increasing M. abscessus survival.}, } @article {pmid31451499, year = {2019}, author = {Albano, M and Karau, MJ and Greenwood-Quaintance, KE and Osmon, DR and Oravec, CP and Berry, DJ and Abdel, MP and Patel, R}, title = {In Vitro Activity of Rifampin, Rifabutin, Rifapentine, and Rifaximin against Planktonic and Biofilm States of Staphylococci Isolated from Periprosthetic Joint Infection.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {11}, pages = {}, pmid = {31451499}, issn = {1098-6596}, support = {R21 AI125870/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*therapeutic use ; Arthritis, Infectious/*drug therapy/metabolism ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests/methods ; Plankton/*drug effects ; Prosthesis-Related Infections/*drug therapy/microbiology ; Rifabutin/therapeutic use ; Rifampin/analogs & derivatives/therapeutic use ; Rifaximin/therapeutic use ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus/*drug effects ; }, abstract = {The in vitro activities of rifampin, rifabutin, rifapentine, and rifaximin were tested against 200 periprosthetic joint infection (PJI)-associated staphylococci. Seven rifampin-resistant isolates had MICs of ≥4 μg/ml. Three isolates had rifampin MICs of 0.25 to 1 μg/ml and harbored an Asp471Gly RpoB variant, suggesting that the CLSI rifampin-susceptible staphylococcal breakpoint of ≤1 μg/ml may be too high. The remaining isolates had rifampin MICs of ≤0.016 μg/ml, and the rifampin, rifabutin, rifapentine, and rifaximin minimum biofilm bactericidal concentrations (MBBC) for ≥50% of isolates were 8, 1, 2, and 4 μg/ml (for S. aureus) and 2, 0.06, 0.25, and 0.5 μg/ml (for S. epidermidis), respectively, for rifampin-susceptible isolates. Nonrifampin rifamycins have promising staphylococcal activity, including antibiofilm activity.}, } @article {pmid31450779, year = {2019}, author = {Llamazares, C and Sanz Del Olmo, N and Ortega, P and Gómez, R and Soliveri, J and de la Mata, FJ and García-Gallego, S and Copa-Patiño, JL}, title = {Antibacterial Effect of Carbosilane Metallodendrimers in Planktonic Cells of Gram-Positive and Gram-Negative Bacteria and Staphylococcus aureus Biofilm.}, journal = {Biomolecules}, volume = {9}, number = {9}, pages = {}, pmid = {31450779}, issn = {2218-273X}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Coordination Complexes/chemistry/pharmacology ; Copper/chemistry ; Dendrimers/chemistry/*pharmacology ; Erythrocytes/cytology/metabolism ; Gram-Negative Bacteria/drug effects/*physiology ; Gram-Positive Bacteria/drug effects/*physiology ; Hemolysis/drug effects ; Microbial Sensitivity Tests ; Ruthenium/chemistry ; Sheep ; Silanes/chemistry ; Staphylococcus aureus/drug effects/*physiology ; }, abstract = {Antibiotic resistance is currently one of the main threats to public health security. Biofilm formation is a resistance mechanism that is responsible for most human bacterial infections and requires new and effective therapeutic approaches, such as those provided by nanotechnology. In this work, the antibacterial effect of carbosilane metallodendrimers with different metals (copper(II) and ruthenium(II)), ligands (chloride and nitrate) and generations (generation 0, 1 and 2) has been studied using planktonic Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Furthermore, the ability of the metallodendrimers to avoid the formation of S. aureus biofilms was also evaluated. The results showed a promising biocide activity in both types of planktonic bacteria, especially for first-generation dendrimers, which arises from the metal complexation to the dendrimer. Cu(II) metallodendrimers require lower concentration than Ru(II) counterpart to inhibit the production of S. aureus biofilms, but none produce hemolysis at the inhibitory concentrations and can be safely used as antibacterial agents. In particular, the first-generation Cu(II) metallodendrimer with nitrate ligands displayed the most promising properties to continue with further studies in both planktonic cells and biofilms.}, } @article {pmid31450696, year = {2019}, author = {Smolobochkin, A and Gazizov, A and Sazykina, M and Akylbekov, N and Chugunova, E and Sazykin, I and Gildebrant, A and Voronina, J and Burilov, A and Karchava, S and Klimova, M and Voloshina, A and Sapunova, A and Klimanova, E and Sashenkova, T and Allayarova, U and Balakina, A and Mishchenko, D}, title = {Synthesis of Novel 2-(Het)arylpyrrolidine Derivatives and Evaluation of Their Anticancer and Anti-Biofilm Activity.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {17}, pages = {}, pmid = {31450696}, issn = {1420-3049}, mesh = {Animals ; Anti-Infective Agents/*chemical synthesis/chemistry/*pharmacology ; Antineoplastic Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Cell Line, Tumor ; Chemistry Techniques, Synthetic ; Dose-Response Relationship, Drug ; Humans ; Mice ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Conformation ; Molecular Structure ; Pyrrolidines/*chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {A library of novel 2-(het)arylpyrrolidine-1-carboxamides were obtained via a modular approach based on the intramolecular cyclization/Mannich-type reaction of N-(4,4-diethoxybutyl)ureas. Their anti-cancer activities both in vitro and in vivo were tested. The in vitro activity of some compounds towards M-Hela tumor cell lines was twice that of the reference drug tamoxifen, whereas cytotoxicity towards normal Chang liver cell did not exceed the tamoxifen toxicity. In vivo studies showed that the number of surviving animals on day 60 of observation was up to 83% and increased life span (ILS) was up to 447%. Additionally, some pyrrolidine-1-carboxamides possessing a benzofuroxan moiety obtained were found to effectively suppress bacterial biofilm growth. Thus, these compounds are promising candidates for further development both as anti-cancer and anti-bacterial agents.}, } @article {pmid31450579, year = {2019}, author = {Wijesundara, NM and Rupasinghe, HPV}, title = {Herbal Tea for the Management of Pharyngitis: Inhibition of Streptococcus pyogenes Growth and Biofilm Formation by Herbal Infusions.}, journal = {Biomedicines}, volume = {7}, number = {3}, pages = {}, pmid = {31450579}, issn = {2227-9059}, support = {CRDPJ 448052//Natural Sciences and Engineering Research Council of Canada/ ; }, abstract = {Herbal teas are becoming popular as functional beverages due to their various health promotional properties. This study aimed at assessing 13 hot water infusions (HWIs) from different herbs against streptococcal pharyngitis (strep throat). Licorice root exhibited the lowest minimum inhibitory concentrations (MIC) of 1.56 mg/mL, followed by barberry root, thyme, and oregano flowering shoots, with a MIC of 3.13 mg/mL. At their respective minimum bactericidal concentrations (MBC), licorice showed the bactericidal effect on S. pyogenes within 12 h after exposure while others need 24 h for a similar outcome. The HWIs exhibited inhibitory activity on biofilm formation, ranging from 1.56 to 6.25 mg/mL, which confirmed by ruptured cells or clusters of dead cell debris observed in scanning electron microscope (SEM). Overall, non-toxic concentrations of efficacious HWIs from licorice root, barberry root, thyme, and oregano flowering shoots may provide potential sources for developing herbal teas or biomedicine for the management of S. pyogenes infections.}, } @article {pmid31450202, year = {2019}, author = {Sinharoy, A and Baskaran, D and Pakshirajan, K}, title = {A novel carbon monoxide fed moving bed biofilm reactor for sulfate rich wastewater treatment.}, journal = {Journal of environmental management}, volume = {249}, number = {}, pages = {109402}, doi = {10.1016/j.jenvman.2019.109402}, pmid = {31450202}, issn = {1095-8630}, mesh = {Biofilms ; *Bioreactors ; Carbon Monoxide ; Sulfates ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {In this study, a moving bed biofilm reactor was used for biodesulfuruization using CO as the sole carbon substrate. The effect of hydraulic retention time (HRT), sulfate loading rate and CO loading rate on sulfate and CO removal was examined. At 72, 48 and 24 h HRT, the sulfate removal was 93.5%, 91.9% and 80.1%, respectively. An increase in the sulfate loading reduced the sulfate reduction efficiency, which, however, was improved by increasing the CO flow rate into the MBBR. Best results in terms of sulfate reduction (>80%) were obtained for low inlet sulfate and high CO loading conditions. The CO utilization was very high at 85% throughout the study, except during the last phase of the continuous bioreactor operation it was around 70%. An artificial neural network based model was successfully developed and optimized to accurately predict the bioreactor performance in terms of both sulfate reduction and CO utilization. Overall, this study showed an excellent potential of the moving bed biofilm bioreactor for efficient sulfate reduction even under high loading conditions.}, } @article {pmid31448272, year = {2019}, author = {Saggu, SK and Jha, G and Mishra, PC}, title = {Enzymatic Degradation of Biofilm by Metalloprotease From Microbacterium sp. SKS10.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {7}, number = {}, pages = {192}, pmid = {31448272}, issn = {2296-4185}, abstract = {Enzymes have replaced or decreased usage of toxic chemicals for industrial and medical applications leading toward sustainable chemistry. In this study, we report purification and characterization of a biofilm degrading protease secreted by Microbacterium sp. SKS10. The protease was identified as a metalloprotease, Peptidase M16 using mass spectrometry. It showed optimum activity at 60°C, pH 12 and retained its activity in the presence of various salts and organic solvents. The enzyme was able to degrade biofilms efficiently at enzyme concentration lower than other known enzymes such as papain, trypsin and α-amylase. The presence of this protease increased the accessibility of antibiotics inside the biofilm, and was found to be non-cytotoxic toward human epidermoid carcinoma cells (A431) at the effective concentration for biofilm degradation. Thus, this protease may serve as an effective tool for management of biofilms.}, } @article {pmid31448253, year = {2019}, author = {Ciccozzi, M and Cella, E and Lai, A and De Florio, L and Antonelli, F and Fogolari, M and Di Matteo, FM and Pizzicannella, M and Colombo, B and Dicuonzo, G and Angeletti, S}, title = {Phylogenetic Analysis of Multi-Drug Resistant Klebsiella pneumoniae Strains From Duodenoscope Biofilm: Microbiological Surveillance and Reprocessing Improvements for Infection Prevention.}, journal = {Frontiers in public health}, volume = {7}, number = {}, pages = {219}, pmid = {31448253}, issn = {2296-2565}, abstract = {Duodenoscopes have been described as potential vehicles of patient-to-patient transmission of multi-drug resistant organisms. Carbapenem-resistant Enterobacteriaceae duodenoscope related infections have been described by the Center for Disease Control and the US Food and Drug Administration consequently to outbreaks occurring in the United States. These evidences suggested that improved microbiological surveillance and endoscope design optimization could represent valid tools to improve infection control. At this aim, in this study an example of duodenoscope microbiological surveillance and reprocessing improvement analyzing strains component of bacterial biofilm by phylogenetic analysis has been proposed. From September 2016 to December 2017, duodenoscope instruments were subjected to microbial surveillance by post-reprocessing cultures of liquid collected by internal channels of instruments after injection and aspiration cycles and membrane filtration. During surveillance seventeen Klebsiella pneumoniae, of which 10/17 (58.8%) MDR and KPC strains were collected from duodenoscope instruments plus one MDR Klebsiella pneumoniae strain from the rectal swab performed before ERCP procedure in an inpatient. The surveillance allowed evidencing potential failure of reprocessing procedure and performing consequent reprocessing improvements including the contaminated instruments quarantine until their negativity. Phylogenetic analysis of whole genome sequence of duodenoscope strains plus inpatients MDR strains, showed intermixing between duodenoscopes and inpatients, as evidenced by minimum spanning tree and time-scale Maximum Clade Credibility tree. In minimum spanning tree, three groups have been evidenced. Group I including Klebsiella pneumoniae strains, isolated from inpatients before microbiological surveillance adoption; group II including intermixed Klebsiella pneumoniae strains isolated from inpatients and Klebsiella pneumoniae strains isolated from duedonoscopes and group III including Klebsiella pneumoniae strains exclusively from duedonoscope instruments. In the Maximum Credibility Tree, a statistically supported cluster including two Klebsiella pneumoniae strains from duedonoscope instruments and one strains isolated from an inpatient was showed. From the first microbiologic surveillance performed on September 2016 and after the reprocessing improvement adoption, none MDR or susceptible Klebsiella pneumoniae strain was isolated in the following surveillance periods. In conclusion, these results should encourage hospital board to perform microbiological surveillance of duodenoscopes as well as of patients, by rectal swabs culture, and rapid molecular testing for antimicrobial resistance before any endoscopic invasive procedure.}, } @article {pmid31447791, year = {2019}, author = {Kesy, K and Oberbeckmann, S and Kreikemeyer, B and Labrenz, M}, title = {Spatial Environmental Heterogeneity Determines Young Biofilm Assemblages on Microplastics in Baltic Sea Mesocosms.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1665}, pmid = {31447791}, issn = {1664-302X}, abstract = {Microplastics in aquatic environments provide novel habitats for surface-colonizing microorganisms. Given the continuing debate on whether substrate-specific properties or environmental factors prevail in shaping biofilm assemblages on microplastics, we examined the influence of substrate vs. spatial factors in the development of bacterial assemblages on polyethylene (PE), polystyrene (PS), wood, and seston and in the free-living fraction. Further, the selective colonization of microplastics by potential pathogens was investigated because among the bacterial species found in microplastic-associated biofilms are potentially pathogenic Vibrio spp. Due to their persistence and great dispersal potential, microplastics could act as vectors for these potential pathogens and for biofilm assemblages in general. Incubation experiments with these substrates were conducted for 7 days during a summer cruise along the eastern Baltic Sea coastline in waters covering a salinity gradient of 4.5-9 PSU. Bacterial assemblages were analyzed using 16S rRNA-gene amplicon sequencing, distance-based redundancy analyses, and the linear discriminant analysis effect size method to identify taxa that were significantly more abundant on the plastics. The results showed that the sample type was the most important factor structuring bacterial assemblages overall. Surface properties were less significant in differentiating attached biofilms on PE, PS, and wood; instead, environmental factors, mainly salinity, prevailed. A potential role for inorganic-nutrient limitations in surface-specific attachment was identified as well. Alphaproteobacteria (Sphingomonadaceae, Devosiaceae, and Rhodobacteraceae) and Gammaproteobacteria (Alteromonadaceae and Pseudomonas) were distinctive for the PE- and PS-associated biofilms. Vibrio was more abundant on the PE and PS biofilms than on seston, but its abundances were highest on wood and positively correlated with salinity. These results corroborate earlier findings that microplastics constitute a habitat for biofilm-forming microorganisms distinct from seston, but less from wood. In contrast to earlier reports of low Vibrio numbers on microplastics, these results also suggest that vibrios are early colonizers of surfaces in general. Spatial as well as temporal dynamics should therefore be considered when assessing the potential of microplastics to serve as vectors for bacterial assemblages and putative pathogens, as these parameters are major drivers of biofilm diversity.}, } @article {pmid31447460, year = {2019}, author = {Wu, S and Liu, Y and Zhang, H and Lei, L}, title = {A new transformation method with nanographene oxides of antisense carrying yycG RNA improved antibacterial properties on methicillin-resistant Staphylococcus aureus biofilm.}, journal = {The Journal of veterinary medical science}, volume = {81}, number = {10}, pages = {1540-1546}, pmid = {31447460}, issn = {1347-7439}, mesh = {Animals ; Biofilms/*drug effects ; Genetic Vectors/*chemical synthesis/genetics/pharmacology ; Graphite ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics ; RNA, Antisense/*administration & dosage ; Staphylococcal Infections/microbiology/prevention & control ; Transformation, Bacterial ; }, abstract = {Staphylococcus aureus has the potential to opportunistically cause infectious diseases. The aim of this study was to determine the antimicrobial effects of novel graphene oxide (GO)-polyethylenimine (PEI)-based antisense yycG (ASyycG) on the inhibition of methicillin-resistant S. aureus (MRSA) biofilm formation. In current study, a novel GO-PEI-based recombinant ASyycG vector transformation strategy was developed to produce ASyycG. The mechanical features including zeta-potential and particle size distributions were evaluated by: GO; GO-PEI and GO-PEI-ASyycG. The recombinant ASyycG vector was transformed into MRSA cells, and the expression levels of the yycF/G and icaADB genes were determined and compared by quantitative real-time PCR (qPCR) assays. The recombinant ASyycG plasmids were subsequently modified with a gene encoding enhanced green fluorescent protein (ASyycG-eGFP) as a reporter gene, and the transformation efficiency was assessed by the fluorescence intensity. The biofilm biomass and bacterial viability of the MRSA strains were evaluated by crystal violet assay, colony-forming unit assays and confocal laser scanning microscopy. The results showed that the Z-average sizes of GO-PEI-ASyycG were much larger than those of GO or GO-PEI. The GO-PEI-based strategy significantly increased the efficiency of ASyycG transformation. The GO-PEI-ASyycG-transformed MRSA strain had the lowest expression levels of the biofilm formation-associated genes. Furthermore, GO-PEI-ASyycG suppressed biofilm aggregation and improved bactericidal effects on the MRSA after 24 hr of biofilm establishment. Our findings demonstrated that GO-PEI based antisense yycG RNA will be an effective method for management of MRSA infections.}, } @article {pmid31445309, year = {2019}, author = {Wu, X and Pan, J and Li, M and Li, Y and Bartlam, M and Wang, Y}, title = {Selective enrichment of bacterial pathogens by microplastic biofilm.}, journal = {Water research}, volume = {165}, number = {}, pages = {114979}, doi = {10.1016/j.watres.2019.114979}, pmid = {31445309}, issn = {1879-2448}, mesh = {Anti-Bacterial Agents ; *Bacteria ; Biofilms ; Drug Resistance, Microbial ; Genes, Bacterial ; Humans ; *Plastics ; RNA, Ribosomal, 16S ; }, abstract = {Microplastics have been found to be ubiquitous in freshwater ecosystems, providing a novel substrate for biofilm formation. Here, we incubated biofilm on microplastics and two natural substrates (rock and leaf) under a controlled environment to investigate the differences of microbial community structure, antibiotic resistance gene (ARG) profiles, and ARG microbial hosts between biofilms on three types of substrates. Results from high-throughput sequencing of 16S rRNA gene revealed that microplastic biofilm had a distinctive community structure. Network analyses suggested that microplastic biofilm possessed the highest node connected community, but with lower average path length, network diameter and modularity compared with biofilm on two natural particles. Metagenomic analyses further revealed microplastic biofilm with broad-spectrum and distinctive resistome. Specifically, according to taxonomic annotation of ARG microbial hosts, two opportunisitic human pathogens (Pseudomonas monteilii, Pseudomonas mendocina) and one plant pathogen (Pseudomonas syringae) were detected only in the microplastic biofilm, but not in biofilms formed on natural substrates. Our findings suggest that microplastic is a novel microbial niche and may serve as a vector for ARGs and pathogens to new environment in river water, generating freshwater environmental risk and exerting adverse impacts on human health.}, } @article {pmid31444121, year = {2019}, author = {Cui, MH and Sangeetha, T and Gao, L and Wang, AJ}, title = {Efficient azo dye wastewater treatment in a hybrid anaerobic reactor with a built-in integrated bioelectrochemical system and an aerobic biofilm reactor: Evaluation of the combined forms and reflux ratio.}, journal = {Bioresource technology}, volume = {292}, number = {}, pages = {122001}, doi = {10.1016/j.biortech.2019.122001}, pmid = {31444121}, issn = {1873-2976}, mesh = {Anaerobiosis ; Azo Compounds ; Biofilms ; *Bioreactors ; Coloring Agents ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {A combined process that consisted of a hybrid anaerobic reactor (HAR) with an integral bioelectrochemical system and aerobic biofilm reactor (ABFR) was established for simulated azo dye wastewater treatment (domestic wastewater containing dye acid orange 7). The split combination form that separated HAR and ABFR into two individual reactors recorded a decolorization efficiency of 81.23 ± 0.12%, which was about 8% higher than that HAR and ABFR were stacked together into a single up-flow reactor. Implementation of reflux improved the decolorization and chemical oxygen demand (COD) removal in both the processes. Decolorization efficiency achieved 97.52 ± 0.66% in split process at a reflux ratio of 1 and the COD was 89 ± 2 mg/L in the final effluent. Further increasing the reflux ratio to 3 did not have any significance in treatment performance of the reactors. This study comprehensively revealed the influence of combination forms and reflux ratio on the performance of combined process.}, } @article {pmid31444120, year = {2019}, author = {Sun, S and Liu, J and Zhang, M and He, S}, title = {Simultaneous improving nitrogen removal and decreasing greenhouse gas emission with biofilm carriers addition in ecological floating bed.}, journal = {Bioresource technology}, volume = {292}, number = {}, pages = {121944}, doi = {10.1016/j.biortech.2019.121944}, pmid = {31444120}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Greenhouse Gases ; *Nitrogen ; }, abstract = {Ecological floating bed (EFB) is a green technology for treatment of micro-polluted wastewater. However, its nitrogen removal efficiency is still unsatisfactory. In this study, two EFBs with additional carbon source were established to explore biofilm carriers addition on nitrogen removal and greenhouse gas (GHG) emissions at different C/N ratios and temperatures. Results showed that biofilm carriers addition increased nitrification and nitrogen removal efficiencies in EFB, and more denitrifying and nitrifying bacteria were attached to the biofilm carriers. Higher N2O and CH4 emissions were found in control EFB without biofilm carriers addition which was consistent with higher nitrite accumulation. In addition, high-throughput sequencing analysis revealed that adding biofilm carriers could improve the richness and diversity of biological communities. For EFB with additional carbon source treating secondary effluent, adding biofilm carrier can obtain higher TN removal efficiency and lower greenhouse gas emission.}, } @article {pmid31443467, year = {2019}, author = {Arul Selvaraj, RC and Rajendran, M and Nagaiah, HP}, title = {Re-Potentiation of β-Lactam Antibiotic by Synergistic Combination with Biogenic Copper Oxide Nanocubes against Biofilm Forming Multidrug-Resistant Bacteria.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {17}, pages = {}, pmid = {31443467}, issn = {1420-3049}, support = {(Ref: NM/NS/01/2015 (G) dated 30 May,2016//DST, Nano Mission, India/ ; }, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacterial Infections/microbiology ; Biofilms/*drug effects ; Burns/complications ; Cell Survival/drug effects ; Copper/*administration & dosage/chemistry ; Drug Resistance, Multiple, Bacterial/*drug effects ; Fibroblasts/drug effects ; Humans ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Urinary Catheters/microbiology ; beta-Lactams/isolation & purification/*pharmacology ; }, abstract = {Biofilm-associated tissue and device infection is a major threat to therapy. The present work aims to potentiate β-lactam antibiotics with biologically synthesized copper oxide nanoparticles. The synergistic combination of amoxyclav with copper oxide nanoparticles was investigated by checkerboard assay and time-kill assay against bacteria isolated from a burn wound and a urinary catheter. The control of biofilm formation and extracellular polymeric substance production by the synergistic combination was quantified in well plate assay. The effect of copper oxide nanoparticles on the viability of human dermal fibroblasts was evaluated. The minimum inhibitory concentration and minimum bactericidal concentration of amoxyclav were 70 μg/mL and 140 μg/mL, respectively, against Proteus mirabilis and 50 μg/mL and 100 μg/mL, respectively, against Staphylococcus aureus. The synergistic combination of amoxyclav with copper oxide nanoparticles reduced the minimum inhibitory concentration of amoxyclav by 16-fold against P. mirabilis and 32-fold against S. aureus. Above 17.5 μg/mL, amoxyclav exhibited additive activity with copper oxide nanoparticles against P. mirabilis. The time-kill assay showed the efficacy of the synergistic combination on the complete inhibition of P. mirabilis and S. aureus within 20 h and 24 h, respectively, whereas amoxyclav and copper oxide nanoparticles did not inhibit P. mirabilis and S. aureus until 48 h. The synergistic combination of amoxyclav with copper oxide nanoparticles significantly reduced the biofilm formed by P. mirabilis and S. aureus by 85% and 93%, respectively. The concentration of proteins, carbohydrates, and DNA in extracellular polymeric substances of the biofilm was significantly reduced by the synergistic combination of amoxyclav and copper oxide nanoparticles. The fibroblast cells cultured in the presence of copper oxide nanoparticles showed normal morphology with 99.47% viability. No cytopathic effect was observed. Thus, the study demonstrated the re-potentiation of amoxyclav by copper oxide nanoparticles.}, } @article {pmid31443115, year = {2020}, author = {Wroe, JA and Johnson, CT and García, AJ}, title = {Bacteriophage delivering hydrogels reduce biofilm formation in vitro and infection in vivo.}, journal = {Journal of biomedical materials research. Part A}, volume = {108}, number = {1}, pages = {39-49}, pmid = {31443115}, issn = {1552-4965}, support = {F30 AR069472/AR/NIAMS NIH HHS/United States ; T32 GM008169/GM/NIGMS NIH HHS/United States ; R01 AR062920/AR/NIAMS NIH HHS/United States ; }, mesh = {Animals ; Bacteriophages/drug effects/*physiology ; Biofilms/*drug effects/growth & development ; Bone and Bones/microbiology/pathology ; Disease Models, Animal ; Humans ; Hydrogels/*pharmacology ; Male ; Mice, Inbred C57BL ; Polyethylene Glycols/chemistry ; Pseudomonas Infections/microbiology/pathology ; Pseudomonas aeruginosa/drug effects/virology ; }, abstract = {Implanted orthopedic devices become infected more frequently than any other implanted surgical device. These infections can be extremely costly and result in significant patient morbidity. Current treatment options typically involve the long term, systemic administration of a combination of antibiotics, often followed by implant removal. Here we engineered an injectable hydrogel capable of encapsulating Pseudomonas aeruginosa bacteriophage and delivering active phage to the site of bone infections. Bacteriophage retain their bacteriolytic activity after encapsulation and release from the hydrogel, and their rate of release from the hydrogel can be controlled by gel formulation. Bacteriophage-encapsulating hydrogels effectively kill their host bacteria in both planktonic and biofilm phenotypes in vitro without influencing the metabolic activity of human mesenchymal stromal cells. Bacteriophage-encapsulating hydrogels were used to treat murine radial segmental defects infected with P. aeruginosa. The hydrogels achieved a 4.7-fold reduction in live P. aeruginosa counts at the infection site compared to bacteriophage-free hydrogels at 7 days postimplantation. These results support the development of bacteriophage-delivering hydrogels to treat local bone infections.}, } @article {pmid31442835, year = {2019}, author = {Wu, X and Cen, Q and Addy, M and Zheng, H and Luo, S and Liu, Y and Cheng, Y and Zhou, W and Chen, P and Ruan, R}, title = {A novel algal biofilm photobioreactor for efficient hog manure wastewater utilization and treatment.}, journal = {Bioresource technology}, volume = {292}, number = {}, pages = {121925}, doi = {10.1016/j.biortech.2019.121925}, pmid = {31442835}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; *Chlorella vulgaris ; Manure ; *Photobioreactors ; Swine ; Wastewater ; }, abstract = {This study developed a high-efficiency algal biofilm photobioreactor for microalgae by designing a special array of curtain membrane components. This paper also discusses the growth and nutrient composition of Chlorella vulgaris, and hog manure wastewater utilization and purification. It was found that after about 5 days of culture, the biomass of C. vulgaris on the membrane could reach as high as 7.37 g/m[2] and the algae were easily harvested by mechanical scraping. The lipid content of C. vulgaris on the membrane structure was 10.17% while the lipid content of the algae in suspension was 14.29%. The light intensity showed a significant effect on the fatty acid composition. The C. vulgaris grew very well, and achieved deep purification of the hog manure wastewater; the COD, TP, TN, and NH4[+]-N removal rates reached 95.67%, 64.40%, 69.55%, and 91.24%, respectively.}, } @article {pmid31440218, year = {2019}, author = {Todhanakasem, T and Salangsing, OL and Koomphongse, P and Kaewket, S and Kanokratana, P and Champreda, V}, title = {Zymomonas mobilis Biofilm Reactor for Ethanol Production Using Rice Straw Hydrolysate Under Continuous and Repeated Batch Processes.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1777}, pmid = {31440218}, issn = {1664-302X}, abstract = {Plastic composited corn silk was developed as a biotic/abiotic carrier for Zymomonas mobilis biofilm formation for the purpose of ethanol production. Furthermore, we explored the use of rice straw hydrolysate as substrate in both multistage continuous culture and repeated batch processes and compared the ethanol production efficiency by two strains of Z. mobilis. Biofilm formed by bacterial strains Z. mobilis ZM4 and TISTR551 were detected, and its proficiencies were compared under various conditions by scanning electron microscopy (SEM) and crystal violet assays. The greatest biofilm formed by both strains was found on day five after the inoculation. Z. mobilis strain ZM4 grown in repeated batch biofilm reactors produced higher yields of ethanol than TISTR551 grown under the same conditions, while TISTR551 produced higher yields of ethanol in the multistage continuous process. The yields were highly maintained, with no significant differences (p < 0.05) among the three consecutive repeated batches. These experiments highlight exciting uses for agricultural byproducts in the production of ethanol using Z. mobilis biofilm reactors.}, } @article {pmid31440064, year = {2019}, author = {Shariati, A and Asadian, E and Fallah, F and Azimi, T and Hashemi, A and Yasbolaghi Sharahi, J and Taati Moghadam, M}, title = {Evaluation of Nano-curcumin effects on expression levels of virulence genes and biofilm production of multidrug-resistant Pseudomonas aeruginosa isolated from burn wound infection in Tehran, Iran.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {2223-2235}, pmid = {31440064}, issn = {1178-6973}, abstract = {BACKGROUND: P. aeruginosa is considered as one of the most important pathogens, and high antibiotic resistance to P. aeruginosa has become an alarming concern. This study attempts to further improve curcumin solubility and stability by producing the involved nanoparticle and investigate the effect of this nanoparticle on those virulence genes of P. aeruginosa in pathogenicity and biofilm formation.

METHODS: In this study, the curcumin nanoparticles were synthesized and characterized, and the antibacterial and antibiofilm effects of Nano-curcumin and curcumin were investigated by microdilution broth and microtiter plate, respectively. In addition, cytotoxic effect of Nano-curcumin on human epithelial cell lines (A549) was determined. The effects of Nano-curcumin on P. aeruginosa virulence genes, mexD, mexB, and mexT (efflux pumps), lecA (adhesion), nfxB (negative regulator of MexCD-OprJ), and rsmZ (biofilm formation) were determined using real-time quantitative PCR.

RESULTS: Synthesized Nano-curcumins were soluble in water, which inhibited the growth of multidrug-resistant (MDR) P. aeruginosa at 128 µg/mL, whereas it was inhibited at 256 µg/mL for soluble curcumin in DMSO. Sub-inhibitory concentrations of Nano-curcumin reduced biofilm formation and, at 64 μg/mL, disrupted 58% of the established bacterial biofilms. In addition, curcumin nanoparticle downregulated the transcription of virulence genes except nfxB and exerted no cytotoxic effect on human epithelial cell lines (A549).

CONCLUSIONS: Results suggest that Nano-curcumin could be potentially used to reduce P. aeruginosa virulence and biofilm. However, in vivo studies with respect to an animal model are necessary to validate these results.}, } @article {pmid31439876, year = {2019}, author = {Champion, AE and Catanzaro, KCF and Bandara, AB and Inzana, TJ}, title = {Formation of the Francisella tularensis Biofilm is Affected by Cell Surface Glycosylation, Growth Medium, and a Glucan Exopolysaccharide.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {12252}, pmid = {31439876}, issn = {2045-2322}, mesh = {Bacterial Vaccines/genetics/metabolism ; Biofilms/*growth & development ; Francisella tularensis/*physiology ; Glycosylation ; O Antigens/genetics/metabolism ; }, abstract = {Biofilms are matrix-associated communities that enable bacteria to colonise environments unsuitable for free-living bacteria. The facultative intracellular pathogen Francisella tularensis can persist in water, amoebae, and arthropods, as well as within mammalian macrophages. F. tularensis Types A and B form poor biofilms, but F. tularensis mutants lacking lipopolysaccharide O-antigen, O-antigen capsule, and capsule-like complex formed up to 15-fold more biofilm than fully glycosylated cells. The Type B live vaccine strain was also 50% less capable of initiating surface attachment than mutants deficient in O-antigen and capsule-like complex. However, the growth medium of all strains tested also influenced the formation of biofilm, which contained a novel exopolysaccharide consisting of an amylose-like glucan. In addition, the surface polysaccharide composition of the bacterium affected the protein:DNA:polysaccharide composition of the biofilm matrix. In contrast, F. novicida attached to surfaces more efficiently and made a more robust biofilm than Type A or B strains, but loss of O-antigen or capsule-like complex did not significantly affect F. novicida biofilm formation. These results indicated that suppression of surface polysaccharides may promote biofilm formation by F. tularensis Types A and B. Whether biofilm formation enhances survival of F. tularensis in aquatic or other environmental niches has yet to be determined.}, } @article {pmid31439670, year = {2019}, author = {Kaus, K and Biester, A and Chupp, E and Lu, J and Visudharomn, C and Olson, R}, title = {The 1.9 Å crystal structure of the extracellular matrix protein Bap1 from Vibrio cholerae provides insights into bacterial biofilm adhesion.}, journal = {The Journal of biological chemistry}, volume = {294}, number = {40}, pages = {14499-14511}, pmid = {31439670}, issn = {1083-351X}, support = {P41 GM103694/GM/NIGMS NIH HHS/United States ; R24 GM098791/GM/NIGMS NIH HHS/United States ; T32 GM008271/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Sequence/genetics ; Amyloid/chemistry ; Bacterial Adhesion/genetics ; Bacterial Proteins/chemistry/genetics/*ultrastructure ; Binding Sites/genetics ; Biofilms ; Cholera/*enzymology/genetics/microbiology ; Crystallography, X-Ray ; Extracellular Matrix Proteins/chemistry/*ultrastructure ; Gene Expression Regulation, Bacterial/genetics ; Lectins/chemistry ; Metals/chemistry ; Polysaccharides/chemistry ; *Protein Conformation ; Vibrio cholerae/chemistry/*enzymology/genetics/pathogenicity ; Virulence Factors/genetics ; }, abstract = {Growth of the cholera bacterium Vibrio cholerae in a biofilm community contributes to both its pathogenicity and survival in aquatic environmental niches. The major components of V. cholerae biofilms include Vibriopolysaccharide (VPS) and the extracellular matrix proteins RbmA, RbmC, and Bap1. To further elucidate the previously observed overlapping roles of Bap1 and RbmC in biofilm architecture and surface attachment, here we investigated the structural and functional properties of Bap1. Soluble expression of Bap1 was possible only after the removal of an internal 57-amino-acid-long hydrophobic insertion sequence. The crystal structure of Bap1 at 1.9 Å resolution revealed a two-domain assembly made up of an eight-bladed β-propeller interrupted by a β-prism domain. The structure also revealed metal-binding sites within canonical calcium blade motifs, which appear to have structural rather than functional roles. Contrary to results previously observed with RbmC, the Bap1 β-prism domain did not exhibit affinity for complex N-glycans, suggesting an altered role of this domain in biofilm-surface adhesion. Native polyacrylamide gel shift analysis did suggest that Bap1 exhibits lectin activity with a preference for anionic or linear polysaccharides. Our results suggest a model for V. cholerae biofilms in which Bap1 and RbmC play dominant but differing adhesive roles in biofilms, allowing bacterial attachment to diverse environmental or host surfaces.}, } @article {pmid31438836, year = {2020}, author = {Pires, MEE and Parreira, AG and Silva, TNL and Colares, HC and da Silva, JA and de Magalhães, JT and Galdino, AS and Gonçalves, DB and Granjeiro, JM and Granjeiro, PA}, title = {Recent Patents on Impact of Lipopeptide on the Biofilm Formation onto Titanium and Stainless Steel Surfaces.}, journal = {Recent patents on biotechnology}, volume = {14}, number = {1}, pages = {49-62}, doi = {10.2174/1872208313666190822150323}, pmid = {31438836}, issn = {2212-4012}, mesh = {Bacillus subtilis/chemistry ; Bacterial Adhesion/drug effects ; Bacterial Proteins/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Humans ; Lipopeptides/*pharmacology ; *Patents as Topic ; Prosthesis Design ; Prosthesis-Related Infections/prevention & control ; *Stainless Steel ; Staphylococcus aureus/drug effects ; Surface Properties ; *Titanium ; }, abstract = {BACKGROUND: Numerous causes of infection in arthroplasties are related to biofilm formation on implant surfaces. In order to circumvent this problem, new alternatives to prevent bacterial adhesion biosurfactants-based are emerging due to low toxicity, biodegradability and antimicrobial activity of several biosurfactants. We revised all patents relating to biosurfactants of applicability in orthopedic implants.

METHODS: This work aims to evaluate the capability of a lipopeptide produced by Bacillus subtilis ATCC 19659 isolates acting as inhibitors of the adhesion of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 onto titanium and stainless steel surfaces and its antimicrobial activity.

RESULTS: The adhesion of the strains to the stainless-steel surface was higher than that of titanium. Preconditioning of titanium and stainless-steel surfaces with 10 mg mL-1 lipopeptide reduced the adhesion of E. coli by up to 93% and the adhesion of S. aureus by up to 99.9%, suggesting the strong potential of lipopeptides in the control of orthopedic infections. The minimal inhibitory concentration and minimum bactericidal concentration were 10 and 240 µg mL-1 for E. coli and S. aureus, respectively.

CONCLUSION: The lipopeptide produced by Bacillus subtilis ATCC 19659 presented high biotechnological application in human health against orthopedic implants infections.}, } @article {pmid31438656, year = {2019}, author = {Skowron, K and Wałecka-Zacharska, E and Grudlewska, K and Gajewski, P and Wiktorczyk, N and Wietlicka-Piszcz, M and Dudek, A and Skowron, KJ and Gospodarek-Komkowska, E}, title = {Disinfectant Susceptibility of Biofilm Formed by Listeria monocytogenes under Selected Environmental Conditions.}, journal = {Microorganisms}, volume = {7}, number = {9}, pages = {}, pmid = {31438656}, issn = {2076-2607}, abstract = {Listeria monocytogenes is a one of the most important food-borne pathogens. Its ability to form biofilm contributes to increased resistance to disinfectants and inefficient disinfection, posing a serious threat for the food industry, and in the end the consumer. The aim of this study was the comparison of the biofilm formation ability of L. monocytogenes strains on stainless steel, under different environmental conditions (temperature, pH, NaCl concentration, nutrients availability), and the assessment of biofilm susceptibility to disinfectants. The bactericidal activity of four disinfectants in two concentrations (100% and 50% of working solution) against biofilm was conducted on four clinical strains, four strains isolated from food and one reference strain ATCC 19111. It was found that biofilm susceptibility to disinfectants was influenced by environmental conditions. Biofilm susceptibility correlated with the decrease of temperature, pH, nutrients availability and salinity of the environment. The least sensitive to disinfectants was biofilm produced at pH = 4 (the bacterial number ranged from 0.25 log CFU × cm[-2] to 1.72 log CFU × cm[-2]) whereas the most sensitive was biofilm produced at pH = 9 (5.16 log CFU × cm[-2] to 7.84 log CFU × cm[-2]). Quatosept was the most effective disinfectant, regardless of the conditions. In conclusion, biofilm susceptibility to disinfectants is strain-dependent and is affected by environmental conditions.}, } @article {pmid31438629, year = {2019}, author = {Lorenzo, D}, title = {Chloramphenicol Resurrected: A Journey from Antibiotic Resistance in Eye Infections to Biofilm and Ocular Microbiota.}, journal = {Microorganisms}, volume = {7}, number = {9}, pages = {}, pmid = {31438629}, issn = {2076-2607}, abstract = {The advent of multidrug resistance among pathogenic bacteria is devastating the worth of antibiotics and changing the way of their administration, as well as the approach to use new or old drugs. The crisis of antimicrobial resistance is also due to the unavailability of newer drugs, attributable to exigent regulatory requirements and reduced financial inducements. The emerging resistance to antibiotics worldwide has led to renewed interest in old drugs that have fallen into disuse because of toxic side effects. Thus, comprehensive efforts are needed to minimize the pace of resistance by studying emergent microorganisms and optimize the use of old antimicrobial agents able to maintain their profile of susceptibility. Chloramphenicol is experiencing its renaissance because it is widely used in the treatment and prevention of superficial eye infections due to its broad spectrum of activity and other useful antimicrobial peculiarities, such as the antibiofilm properties. Concerns have been raised in the past for the risk of aplastic anemia when chloramphenicol is given intravenously. Chloramphenicol seems suitable to be used as topical eye formulation for the limited rate of resistance compared to fluoroquinolones, for its scarce induction of bacterial resistance and antibiofilm activity, and for the hypothetical low impact on ocular microbiota disturbance. Further in-vitro and in vivo studies on pharmacodynamics properties of ocular formulation of chloramphenicol, as well as its real impact against biofilm and the ocular microbiota, need to be better addressed in the near future.}, } @article {pmid31437576, year = {2019}, author = {Khan, F and Jeong, MC and Park, SK and Kim, SK and Kim, YM}, title = {Contribution of chitooligosaccharides to biofilm formation, antibiotics resistance and disinfectants tolerance of Listeria monocytogenes.}, journal = {Microbial pathogenesis}, volume = {136}, number = {}, pages = {103673}, doi = {10.1016/j.micpath.2019.103673}, pmid = {31437576}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Chitin/*analogs & derivatives/metabolism ; Chitosan ; Disinfectants/*pharmacology ; *Drug Tolerance ; Listeria monocytogenes/drug effects/*growth & development ; Oligosaccharides ; }, abstract = {Listeria monocytogenes is a food-borne pathogen present in various environmental reservoirs. It exhibits resistance and tolerance to antibiotics and sanitizing agents used in several food processing industries. It has been reported that L. monocytogenes chitinase can catalyze hydrolysis of chitin polymeric carbohydrate present in the environment and act as a virulence factor that support its survival in mammalian host cells. By taking advantage of chitinase, L. monocytogenes has both saprophytic and pathogenic lifestyles in the soil and the living host, respectively. The objective of the present study was to determine the involvement of chitin degradation products such as chitooligosaccharides (COS) in biofilm formation of L. monocytogenes. Results showed that different concentrations of COS with various molecular weight enhanced biofilm formation of L. monocytogenes. Such enhancement in biofilm formation contributed to the development of antibiotics resistance and disinfectants tolerance of cells present in the biofilm. The present article also described diverse roles of chitin, chitinase, and degradation of chitin and chitin-like substrates in saprophytic and pathogenic lifestyles of L. monocytogenes. This study offers a new direction for further exploration of the mechanisms of pathogenesis caused by L. monocytogenes.}, } @article {pmid31437202, year = {2019}, author = {Romero-Lastra, P and Sánchez, MC and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M}, title = {Gene expression of Porphyromonas gingivalis ATCC 33277 when growing in an in vitro multispecies biofilm.}, journal = {PloS one}, volume = {14}, number = {8}, pages = {e0221234}, pmid = {31437202}, issn = {1932-6203}, mesh = {Actinomyces/genetics ; Aggregatibacter actinomycetemcomitans/genetics ; Anaerobiosis/genetics ; Biofilms/*growth & development ; Culture Media/chemistry ; Durapatite ; Fusobacterium nucleatum/genetics ; *Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Humans ; Plankton/*genetics/growth & development ; Porphyromonas gingivalis/*genetics/growth & development ; RNA, Bacterial ; Streptococcus oralis/genetics ; *Transcriptome ; Veillonella/genetics ; }, abstract = {BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis, an oral microorganism residing in the subgingival biofilm, may exert diverse pathogenicity depending on the presence of specific virulence factors, but its gene expression has not been completely established. This investigation aims to compare the transcriptomic profile of this pathogen when growing within an in vitro multispecies biofilm or in a planktonic state.

MATERIALS AND METHODS: P. gingivalis ATCC 33277 was grown in anaerobiosis within multi-well culture plates at 37°C under two conditions: (a) planktonic samples (no hydroxyapatite discs) or (b) within a multispecies-biofilm containing Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans deposited on hydroxyapatite discs. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) combined with Fluorescence In Situ Hybridization (FISH) were used to verify the formation of the biofilm and the presence of P. gingivalis. Total RNA was extracted from both the multispecies biofilm and planktonic samples, then purified and, with the use of a microarray, its differential gene expression was analyzed. A linear model was used for determining the differentially expressed genes using a filtering criterion of two-fold change (up or down) and a significance p-value of <0.05. Differential expression was confirmed by Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR).

RESULTS: SEM verified the development of the multispecies biofilm and FISH confirmed the incorporation of P. gingivalis. The microarray demonstrated that, when growing within the multispecies biofilm, 19.1% of P. gingivalis genes were significantly and differentially expressed (165 genes were up-regulated and 200 down-regulated), compared with planktonic growth. These genes were mainly involved in functions related to the oxidative stress, cell envelope, transposons and metabolism. The results of the microarray were confirmed by RT-qPCR.

CONCLUSION: Significant transcriptional changes occurred in P. gingivalis when growing in a multispecies biofilm compared to planktonic state.}, } @article {pmid31437081, year = {2021}, author = {Sun, R and Xu, Y and Wu, Y and Tang, J and Esquivel-Elizondo, S and Kerr, PG and Staddon, PL and Liu, J}, title = {Functional sustainability of nutrient accumulation by periphytic biofilm under temperature fluctuations.}, journal = {Environmental technology}, volume = {42}, number = {8}, pages = {1145-1154}, doi = {10.1080/09593330.2019.1659422}, pmid = {31437081}, issn = {1479-487X}, mesh = {Biodiversity ; *Biofilms ; *Ecosystem ; Nutrients ; Seasons ; Temperature ; }, abstract = {Temperature can fluctuate widely between different seasons, and this may greatly impact many biological processes. However, little is known about its influence on the functioning of benthic microbial communities. Here we investigated the nutrient accumulation capability of periphytic biofilm under temperature fluctuations (17-35°C). Periphytic biofilm maintained the same nutrient accumulation capacity after experiencing the 'warming-hot-cooling' temperature fluctuation under both lab and outdoor conditions as those without temperature disturbance. In response to temperature increase, both community composition and species richness changed greatly and the increase in biodiversity was identified as being the underlying mechanism boosting the sustainable function in nutrient accumulation, indicating zero net effects of community changes. These findings provide insights into the underlying mechanisms of how benthic microbial communities adapt to temperature fluctuations to maintain nutrient accumulation capacity and elucidate that periphytic biofilm plays important roles in influencing nutrient cycling in aquatic ecosystems under temperature changes such as seasonal fluctuations.}, } @article {pmid31435968, year = {2019}, author = {Cho, P and Boost, MV}, title = {Evaluation of prevention and disruption of biofilm in contact lens cases.}, journal = {Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)}, volume = {39}, number = {5}, pages = {337-349}, doi = {10.1111/opo.12635}, pmid = {31435968}, issn = {1475-1313}, mesh = {Biguanides/pharmacology ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Contact Lens Solutions/*pharmacology ; Contact Lenses, Hydrophilic/*microbiology ; Disinfectants/*pharmacology ; Humans ; Povidone-Iodine/pharmacology ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; }, abstract = {PURPOSE: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection.

METHOD: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation.

RESULTS: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h.

CONCLUSION: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity.}, } @article {pmid31432881, year = {2019}, author = {Ran, HH and Cheng, X and Bao, YW and Hua, XW and Gao, G and Zhang, X and Jiang, YW and Zhu, YX and Wu, FG}, title = {Multifunctional quaternized carbon dots with enhanced biofilm penetration and eradication efficiencies.}, journal = {Journal of materials chemistry. B}, volume = {7}, number = {33}, pages = {5104-5114}, doi = {10.1039/c9tb00681h}, pmid = {31432881}, issn = {2050-7518}, mesh = {Biofilms/*drug effects ; Carbon/*chemistry ; Escherichia coli/physiology ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Confocal ; Particle Size ; Quantum Dots/chemistry/*toxicity ; Staphylococcus aureus/physiology ; Static Electricity ; }, abstract = {Biofilm formation can lead to the treatment failure of persistent bacterial infections. Although a variety of antibacterial agents have been developed, the restricted drug penetration and the embedded bacteria's potentiated recalcitrance to these agents synergistically lead to the unsatisfactory anti-biofilm effect. Herein, we report the applications of metal-free quaternized carbon dots (CDs) in imaging and eliminating bacterial biofilms. The CDs prepared by the solvothermal treatment of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (abbreviated as Si-QAC) and glycerol possess ultrasmall size (ca. 3.3 ± 0.4 nm) and strong positively charged (zeta potential: ca. +33.1 ± 2.5 mV) surfaces with long alkyl chain-linked quaternary ammonium groups. The small size of the CDs endows them with the penetration ability into the interior of Gram-negative and Gram-positive bacterial biofilms, which enables excellent fluorescence imaging of the biofilms. Due to the different surfaces of the two types of bacteria, the positively charged CDs selectively interact with the more negatively charged Gram-positive bacteria via electrostatic and hydrophobic interactions, which inactivates the Gram-positive bacteria and ultimately eradicates the Gram-positive bacterial biofilms. In addition, we synthesize a new type of quaternized CDs without long alkyl chains (termed TTPAC CDs), and validate that the long alkyl chains potentiate the hydrophobic adhesion between CDs and Gram-positive bacteria. Meanwhile, the crystal violet staining results reveal that the cationic CDs inhibit the formation of Gram-positive bacterial biofilms. Collectively, our work highlights the feasibility of using cationic and ultrasmall metal-free CDs to eliminate and inhibit Gram-positive bacterial biofilms, which represents a highly effective strategy to cope with refractory biofilm-associated infections.}, } @article {pmid31432051, year = {2019}, author = {Kuper, NK and Hollanders, ACC and Dekkers, EAM and Maske, TT and Huysmans, MDNJM and Cenci, MS}, title = {Aging Reduces the Anticaries Effect of Antibacterial Adhesive - An In Vitro Biofilm Study.}, journal = {The journal of adhesive dentistry}, volume = {21}, number = {4}, pages = {365-372}, doi = {10.3290/j.jad.a42999}, pmid = {31432051}, issn = {1757-9988}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Composite Resins ; *Dental Caries ; Dental Cements ; Dentin ; Humans ; }, abstract = {PURPOSE: This in vitro study investigated whether aging different restorative materials influences secondary caries development using a short-term in vitro biofilm model, hypothesizing that the antibacterial adhesive employed may lose its effect over time.

MATERIALS AND METHODS: Sixty enamel-dentin blocks were divided into 6 groups with n = 10 per group. The groups were restored with three different restorative materials, of which each sample contained an artificial gap: composite with conventional adhesive (CCA; negative control), composite with an antibacterial adhesive (CAA), and amalgam (A; positive control). Half of the groups were prepared fresh and half of the groups were submitted to an aging protocol consisting of water storage, thermocycling, storage in human saliva, and storage in 0.9% saline solution. All specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel and dentin next to the different materials was measured as lesion depth (LD) and mineral loss (ML), using transverse wavelength independent microradiography (T-WIM). Regression analysis was used to evaluate the effect of aging on LD and ML per restorative material, corrected for gap size.

RESULTS: In the amalgam group, aging led to shallower lesions and less mineral loss. Fresh amalgam samples showed an average lesion depth of 156.65 ± 39.18 µm at wall dentin locations. Aged amalgam samples had an average lesion depth of 73.42 ± 73.50 µm. Fresh CAA samples showed lower average surface mineral loss values (9104 ± 2631 µm•vol%) than did fresh CCA samples (13166 ± 4769 µm•vol%). After aging, this effect was absent, and the average mineral loss in the CAA group was 13382 ± 5586 µm•vol%, while in the CCA group it was 15518 ± 9283 µm•vol%.

CONCLUSION: Aging can influence secondary caries development either positively or negatively depending on the kind of restorative material. Antibacterial adhesives may lose their effectiveness over time.}, } @article {pmid31430670, year = {2019}, author = {Li, H and Wang, B and Deng, S and Dai, J and Shao, S}, title = {Oxygen-containing functional groups on bioelectrode surface enhance expression of c-type cytochromes in biofilm and boost extracellular electron transfer.}, journal = {Bioresource technology}, volume = {292}, number = {}, pages = {121995}, doi = {10.1016/j.biortech.2019.121995}, pmid = {31430670}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Cytochromes ; Electrodes ; Electron Transport ; Electrons ; Oxygen ; }, abstract = {Introducing oxygen-containing functional groups is a common and convenient method to increase the hydrophilicity of bioelectrodes. In this study, the effect of oxygen-containing functional groups on biofilm was systematically studied to understand how the electron transfer between electrochemically active bacteria (EAB) and bioelectrode was boosted. After electrolysis pretreatment in sulfuric and nitric acid mixture, the oxygen content of the carbon fiber brushes increased from 4.6% to 30.9%. Comparing with the control, the maximum power density increased by 27.7%, while the anode resistance decreased by 21.8%, because charge transfer resistance significantly reduced. The analysis results showed that the content of c-type cytochromes (c-Cyts) in the EAB biofilm was four times higher than that in the control, while the biomass just slightly increased and the bacteria community was similar with that of the control. These findings suggested that the fundamental reason for the enhanced extracellular electron transfer between EAB and electrode was the increased c-Cyts.}, } @article {pmid31430343, year = {2019}, author = {Giacomucci, S and Cros, CD and Perron, X and Mathieu-Denoncourt, A and Duperthuy, M}, title = {Flagella-dependent inhibition of biofilm formation by sub-inhibitory concentration of polymyxin B in Vibrio cholerae.}, journal = {PloS one}, volume = {14}, number = {8}, pages = {e0221431}, pmid = {31430343}, issn = {1932-6203}, mesh = {Antimicrobial Cationic Peptides/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Flagella/*metabolism ; Flagellin/metabolism ; Genes, Bacterial ; Movement ; Polymyxin B/*pharmacology ; Vibrio cholerae O1/drug effects/growth & development/*physiology/ultrastructure ; }, abstract = {Biofilm formation is a common strategy used by bacteria in order to survive and persist in the environment. In Vibrio cholerae (V. cholerae), a Gram-negative pathogen responsible for the cholera disease, biofilm-like aggregates are important for the pathogenesis and disease transmission. Biofilm formation is initiated by the attachment of the bacteria to a surface, followed by maturation stages involving the formation of a biofilm matrix. In V. cholerae, flagella are essential for the initial step of biofilm formation, allowing the bacteria to swim and to detect a surface. In this study, we explored the effect of polymyxin B (PmB), a cationic bacterial antimicrobial peptide, on biofilm formation in pathogenic V. cholerae strains belonging to the O1 and O139 serotypes. We found that sub-inhibitory concentration of PmB induces a reduction of the biofilm formation by V. cholerae O1 and O139. Experiment on preformed biofilm demonstrated that the biofilm formation inhibition occurs at the initial step of biofilm formation, where the flagella are essential. We further characterize the effect of PmB on V. cholerae flagellation. Our results demonstrate that the flagellin expression is not reduced in presence of sub-inhibitory concentration of PmB. However, a decrease of the abundance of flagellin associated with the bacterial cells together with an increase in the secretome was observed. Electron microscopy observations also suggest that the abundance of aflagellated bacteria increases upon PmB supplementation. Finally, in agreement with the effect on the flagellation, a reduction of the bacterial motility is observed. Altogether, our results suggest that the PmB affect V. cholerae flagella resulting in a decrease of the motility and a compromised ability to form biofilm.}, } @article {pmid31430121, year = {2019}, author = {Wang, S and Breslawec, AP and Alvarez, E and Tyrlik, M and Li, C and Poulin, MB}, title = {Differential Recognition of Deacetylated PNAG Oligosaccharides by a Biofilm Degrading Glycosidase.}, journal = {ACS chemical biology}, volume = {14}, number = {9}, pages = {1998-2005}, doi = {10.1021/acschembio.9b00467}, pmid = {31430121}, issn = {1554-8937}, mesh = {Aggregatibacter actinomycetemcomitans/enzymology ; Biocatalysis ; Glycoside Hydrolases/*chemistry/metabolism ; Hydrolysis ; Kinetics ; Oligosaccharides/chemical synthesis/*chemistry/metabolism ; Protein Binding ; Substrate Specificity ; }, abstract = {Exopolysaccharides consisting of partially de-N-acetylated poly-β-d-(1→6)-N-acetyl-glucosamine (dPNAG) are key structural components of the biofilm extracellular polymeric substance of both Gram-positive and Gram-negative human pathogens. De-N-acetylation is required for the proper assembly and function of dPNAG in biofilm development suggesting that different patterns of deacetylation may be preferentially recognized by proteins that interact with dPNAG, such as Dispersin B (DspB). The enzymatic degradation of dPNAG by the Aggregatibacter actinomycetemcomitans native β-hexosaminidase enzyme DspB plays a role in biofilm dispersal. To test the role of substrate de-N-acetylation on substrate recognition by DspB, we applied an efficient preactivation-based one-pot glycosylation approach to prepare a panel of dPNAG trisaccharide analogs with defined acetylation patterns. These analogs served as effective DspB substrates, and the rate of hydrolysis was dependent on the specific substrate de-N-acetylation pattern, with glucosamine (GlcN) located +2 from the site of cleavage being preferentially hydrolyzed. The product distributions support a primarily exoglycosidic cleavage activity following a substrate assisted cleavage mechanism, with the exception of substrates containing a nonreducing GlcN that were cleaved endo leading to the exclusive formation of a nonreducing disaccharide product. These observations provide critical insight into the substrate specificity of dPNAG specific glycosidase that can help guide their design as biocatalysts.}, } @article {pmid31429746, year = {2019}, author = {Funk, B and Kirmayer, D and Sahar-Heft, S and Gati, I and Friedman, M and Steinberg, D}, title = {Efficacy and potential use of novel sustained release fillers as intracanal medicaments against Enterococcus faecalis biofilm in vitro.}, journal = {BMC oral health}, volume = {19}, number = {1}, pages = {190}, pmid = {31429746}, issn = {1472-6831}, mesh = {Anti-Bacterial Agents ; Biofilms ; Delayed-Action Preparations ; *Enterococcus faecalis ; *Root Canal Irrigants/administration & dosage ; }, abstract = {BACKGROUND: Enterococcus faecalis is a bacterium frequently isolated after failed root canal therapy. This study analyzed the antibacterial and antibiofilm effects in vitro of sustained-release fillers (SRF) containing cetylpyridinium chloride (CPC) against vancomycin resistant E. faecalis.

METHODS: First, the solidification capability was tested by introducing liquid SRF into phosphate buffered saline, followed by 30 s of vortexing. The antimicrobial effects of SRF-CPC against static monospecies biofilms were analyzed with a metabolic assay. Inhibition of biofilm formation was tested by exposing daily refreshed E. faecalis suspensions to SRF-CPC for 9 weeks. To evaluate the effects of SRF-CPC against preformed biofilms, biofilms were grown for 1, 3 and 7 days, and then treated with SRF-CPC for 24 h. Biofilm kill time was tested by applying SRF-CPC to a 3-day-old biofilm and measuring its viability at different time points. All experiments were compared to Placebo SRFs and to untreated control biofilms. Data were analyzed with two-way ANOVA followed by Tukey's test. Results were considered significant at P < 0.05.

RESULTS: The liquid SRF solidified within seconds and no structural changes were observed after 30 s of vortexing at maximum speed. SRF-CPC inhibited E. faecalis biofilm formation for 7 weeks and significantly reduced its viability in weeks 8 and 9. Mature biofilms grown for 1, 3 and 7 days were destructed by SRF-CPC in less than 24 h. Fifty percent of a 3-day-old biofilm was destructed in 2 h and complete destruction occurred in less than 12 h. (P < 0.05 in all cases, compared to SRII-Placebo).

CONCLUSIONS: SRF-CPC's physical properties and long-lasting anti-biofilm effects make it a promising coadjuvant medication for endodontic therapy.}, } @article {pmid31429088, year = {2020}, author = {Brodersen, KE and Koren, K and Revsbech, NP and Kühl, M}, title = {Strong leaf surface basification and CO2 limitation of seagrass induced by epiphytic biofilm microenvironments.}, journal = {Plant, cell & environment}, volume = {43}, number = {1}, pages = {174-187}, doi = {10.1111/pce.13645}, pmid = {31429088}, issn = {1365-3040}, mesh = {Bicarbonates/metabolism ; Biofilms ; Carbon Dioxide/chemistry/*metabolism ; Denmark ; Environmental Monitoring ; Hydrogen-Ion Concentration ; Oxygen ; Photosynthesis ; Plant Leaves/*metabolism ; Zosteraceae/*physiology ; }, abstract = {Coastal eutrophication is a growing problem worldwide, leading to increased epiphyte overgrowth of seagrass leaves. Yet little is known about how epiphytes affect key biogeochemical conditions and processes in the seagrass phyllosphere. We used electrochemical microsensors to measure microgradients of O2 , pH, and CO2 at the bare and epiphyte-covered leaf surface of seagrass (Zostera marina L.) to determine effects of epiphytes on the leaf chemical microenvironment. Epiphytes result in extreme daily fluctuations in pH, O2 , and inorganic carbon concentrations at the seagrass leaf surface severely hampering the plant's performance. In light, leaf epiphyte biofilms and their diffusive boundary layer lead to strong basification, markedly reducing the CO2 and HCO3[-] availability at the leaf surface, leading to reduced photosynthetic efficiency as a result of carbon limitation and enhanced photorespiration. With epiphytes, leaf surface pH increased to >10, thereby exceeding final pH levels (~9.62) and CO2 compensation points for active photosynthesis. In darkness, epiphyte biofilms resulted in increased CO2 and hypoxia at the leaf surface. Epiphytes can lead to severe carbon limitation in seagrasses owing to strong phyllosphere basification leading to CO2 depletion and costly, yet limiting, HCO3[-] utilization, increasing the risk of plant starvation.}, } @article {pmid31428077, year = {2019}, author = {Cirri, E and De Decker, S and Bilcke, G and Werner, M and Osuna-Cruz, CM and De Veylder, L and Vandepoele, K and Werz, O and Vyverman, W and Pohnert, G}, title = {Associated Bacteria Affect Sexual Reproduction by Altering Gene Expression and Metabolic Processes in a Biofilm Inhabiting Diatom.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1790}, pmid = {31428077}, issn = {1664-302X}, abstract = {Diatoms are unicellular algae with a fundamental role in global biogeochemical cycles as major primary producers at the base of aquatic food webs. In recent years, chemical communication between diatoms and associated bacteria has emerged as a key factor in diatom ecology, spurred by conceptual and technological advancements to study the mechanisms underlying these interactions. Here, we use a combination of physiological, transcriptomic, and metabolomic approaches to study the influence of naturally co-existing bacteria, Maribacter sp. and Roseovarius sp., on the sexual reproduction of the biofilm inhabiting marine pennate diatom Seminavis robusta. While Maribacter sp. severely reduces the reproductive success of S. robusta cultures, Roseovarius sp. slightly enhances it. Contrary to our expectation, we demonstrate that the effect of the bacterial exudates is not caused by altered cell-cycle regulation prior to the switch to meiosis. Instead, Maribacter sp. exudates cause a reduced production of diproline, the sexual attraction pheromone of S. robusta. Transcriptomic analyses show that this is likely an indirect consequence of altered intracellular metabolic fluxes in the diatom, especially those related to amino acid biosynthesis, oxidative stress response, and biosynthesis of defense molecules. This study provides the first insights into the influence of bacteria on diatom sexual reproduction and adds a new dimension to the complexity of a still understudied phenomenon in natural diatom populations.}, } @article {pmid31428070, year = {2019}, author = {Chen, T and Liu, N and Ren, P and Xi, X and Yang, L and Sun, W and Yu, B and Ying, H and Ouyang, P and Liu, D and Chen, Y}, title = {Efficient Biofilm-Based Fermentation Strategies for L-Threonine Production by Escherichia coli.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1773}, pmid = {31428070}, issn = {1664-302X}, abstract = {Biofilms provide cells favorable growth conditions, which have been exploited in industrial biotechnological processes. However, industrial application of the biofilm has not yet been reported in Escherichia coli, one of the most important platform strains, though the biofilm has been extensively studied for pathogenic reasons. Here, we engineered E. coli by overexpressing the fimH gene, which successfully enhanced its biofilm formation under industrial aerobic cultivation conditions. Subsequently, a biofilm-based immobilized fermentation strategy was developed. L-threonine production was increased from 10.5 to 14.1 g/L during batch fermentations and further to 17.5 g/L during continuous (repeated-batch) fermentations with enhanced productivities. Molecular basis for the enhanced biofilm formation and L-threonine biosynthesis was also studied by transcriptome analysis. This study goes beyond the conventional research focusing on pathogenic aspects of E. coli biofilm and represents a successful application case of engineered E. coli biofilm to industrial processes.}, } @article {pmid31427961, year = {2019}, author = {Oves, M and Rauf, MA and Hussain, A and Qari, HA and Khan, AAP and Muhammad, P and Rehman, MT and Alajmi, MF and Ismail, IIM}, title = {Antibacterial Silver Nanomaterial Synthesis From Mesoflavibacter zeaxanthinifaciens and Targeting Biofilm Formation.}, journal = {Frontiers in pharmacology}, volume = {10}, number = {}, pages = {801}, pmid = {31427961}, issn = {1663-9812}, abstract = {Considering the significance of biological and eco-friendly nanomaterials, in the present study, we have synthesized silver nanoparticles from the exopolysaccharide of recently recovered bacterial strain CEES51 from the Red Sea coastal area of Jeddah, Saudi Arabia. 16S ribosomal RNA gene sequencing was used to characterize the isolated bacteria, and it was identified as Mesoflavibacter zeaxanthinifaciens and assigned an accession number MH707257.1 GenBank. The bacterial strain is an excellent exopolysaccharide producer and survived at hypersaline (30%) and high-temperature (50°C) conditions. The bacterial exopolysaccharides were employed for the fabrication of silver nanoparticles at room temperature. UV-visible spectrophotometer optimized the synthesized nanoparticles, and their size was determined by Nanophox particle size analyzer and dynamic light scattering. Additionally, the X-ray powder diffraction and Fourier-transform infrared spectroscopy studies also approved its crystalline nature and the involvement of organic functional groups in their formation. The synthesized nanomaterials were tested for their antibacterial and antibiofilm properties against pathogenic microorganisms Bacillus subtilis and methicillin-resistant Staphylococcus aureus. The antimicrobial property showed time, and dose-dependent response with a maximum of zone inhibition was observed at around 22 and 18 mm at a dose of 50 µg/well against B. subtilis and S. aureus and a minimum inhibitory concentration of 8 and 10 µg/ml, respectively. Furthermore, the synthesized silver nanoparticles possessed a substantial antibiofilm property and were also found to be biocompatible as depicted by red blood cell lysis assay and their interaction with peripheral blood mononuclear cells and human embryonic kidney 293 cells. Therefore, Mesoflavibacter zeaxanthinifaciens is found to be an excellent source for exopolysaccharide synthesis that assists in the silver nanoparticle production.}, } @article {pmid31427659, year = {2019}, author = {Kindler, O and Pulkkinen, O and Cherstvy, AG and Metzler, R}, title = {Burst statistics in an early biofilm quorum sensing model: the role of spatial colony-growth heterogeneity.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {12077}, pmid = {31427659}, issn = {2045-2322}, mesh = {Bacteria/genetics/*growth & development ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; *Models, Biological ; Quorum Sensing/*genetics ; Signal Transduction/genetics ; }, abstract = {Quorum-sensing bacteria in a growing colony of cells send out signalling molecules (so-called "autoinducers") and themselves sense the autoinducer concentration in their vicinity. Once-due to increased local cell density inside a "cluster" of the growing colony-the concentration of autoinducers exceeds a threshold value, cells in this clusters get "induced" into a communal, multi-cell biofilm-forming mode in a cluster-wide burst event. We analyse quantitatively the influence of spatial disorder, the local heterogeneity of the spatial distribution of cells in the colony, and additional physical parameters such as the autoinducer signal range on the induction dynamics of the cell colony. Spatial inhomogeneity with higher local cell concentrations in clusters leads to earlier but more localised induction events, while homogeneous distributions lead to comparatively delayed but more concerted induction of the cell colony, and, thus, a behaviour close to the mean-field dynamics. We quantify the induction dynamics with quantifiers such as the time series of induction events and burst sizes, the grouping into induction families, and the mean autoinducer concentration levels. Consequences for different scenarios of biofilm growth are discussed, providing possible cues for biofilm control in both health care and biotechnology.}, } @article {pmid31427301, year = {2019}, author = {Bilal, H and Bergen, PJ and Kim, TH and Chung, SE and Peleg, AY and Oliver, A and Nation, RL and Landersdorfer, CB}, title = {Synergistic Meropenem-Tobramycin Combination Dosage Regimens against Clinical Hypermutable Pseudomonas aeruginosa at Simulated Epithelial Lining Fluid Concentrations in a Dynamic Biofilm Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {11}, pages = {}, pmid = {31427301}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms/*drug effects ; Drug Therapy, Combination/methods ; Humans ; Meropenem/*therapeutic use ; Microbial Sensitivity Tests/methods ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Tobramycin/*therapeutic use ; }, abstract = {Exacerbations of chronic Pseudomonas aeruginosa infections are a major treatment challenge in cystic fibrosis due to biofilm formation and hypermutation. We aimed to evaluate different dosage regimens of meropenem and tobramycin as monotherapies and in combination against hypermutable carbapenem-resistant P. aeruginosa A hypermutable P. aeruginosa isolate (meropenem and tobramycin MICs, 8 mg/liter) was investigated in the dynamic CDC biofilm reactor over 120 h. Regimens were meropenem as the standard (2 g every 8 h, 30% epithelial lining fluid [ELF] penetration) and as a continuous infusion (CI; 6 g/day, 30% and 60% ELF penetration) and tobramycin at 10 mg/kg of body weight every 24 h (50% ELF penetration). The time courses of totally susceptible and less-susceptible bacteria and MICs were determined, and antibiotic concentrations were quantified by liquid chromatography-tandem mass spectrometry. All monotherapies failed, with the substantial regrowth of planktonic (>6 log10 CFU/ml) and biofilm (≥6 log10 CFU/cm[2]) bacteria occurring. Except for the meropenem CI (60% ELF penetration), all monotherapies amplified less-susceptible planktonic and biofilm bacteria by 120 h. The meropenem standard regimen with tobramycin caused initial killing followed by considerable regrowth with resistance (meropenem MIC, 64 mg/liter; tobramycin MIC, 32 mg/liter) for planktonic and biofilm bacteria. The combination containing the meropenem CI at both levels of ELF penetration synergistically suppressed the regrowth of total planktonic bacteria and the resistance of planktonic and biofilm bacteria. The combination with the meropenem CI at 60% ELF penetration, in addition, synergistically suppressed the regrowth of total biofilm bacteria. Standard regimens of meropenem and tobramycin were ineffective against planktonic and biofilm bacteria. The combination with meropenem CI exhibited enhanced bacterial killing and resistance suppression of carbapenem-resistant hypermutable P. aeruginosa.}, } @article {pmid31426832, year = {2019}, author = {Bujold, AR and Lani, NR and Sanz, MG}, title = {Strain-to-strain variation of Rhodococcus equi growth and biofilm formation in vitro.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {519}, pmid = {31426832}, issn = {1756-0500}, mesh = {Actinomycetales Infections/*microbiology/veterinary ; Animals ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; Horse Diseases/*microbiology ; Horses/*microbiology ; Host-Pathogen Interactions ; Humans ; Plasmids/genetics ; Polymerase Chain Reaction ; Rhodococcus equi/classification/genetics/*physiology ; Species Specificity ; }, abstract = {OBJECTIVE: Rhodococcus equi is an opportunistic pathogen that causes disease worldwide in young foals and immunocompromised humans. The interactions of R. equi with the host immune system have been described; however, most studies have been conducted using a few well-characterized strains. Because biological differences between R. equi strains are not well characterized, it is unknown if experimental results will replicate when different strains are used. Therefore, our objective was to compare the growth and biofilm formation of low-passage-rate clinical isolates of R. equi to higher-passage-rate, commonly studied isolates to determine whether strain-to-strain variation exists.

RESULTS: Twelve strains were used: 103+, ATCC 33701, UKVDL206 103S harboring a GFP-expressing plasmid, a plasmid-cured 33701 (higher-passage-rate) and seven low-passage clinical isolates. Generation time in liquid revealed fast, moderate-fast, moderate-slow, and slow-growing isolates. The higher-passage-rate isolates were among the moderate-slow growing strains. A strain's rate of growth did not correspond to its ability to form biofilm nor to its colony size on solid media. Based on our results, care should be taken not to extrapolate in vitro work that may be conducted using different R. equi strains. Further work is needed to evaluate the effect that the observed differences may have on experimental results.}, } @article {pmid31424553, year = {2019}, author = {Soares, A and Alexandre, K and Lamoureux, F and Lemée, L and Caron, F and Pestel-Caron, M and Etienne, M}, title = {Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {74}, number = {11}, pages = {3252-3259}, doi = {10.1093/jac/dkz355}, pmid = {31424553}, issn = {1460-2091}, mesh = {Amikacin/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/*pharmacology ; Drug Combinations ; Drug Resistance, Multiple, Bacterial/*genetics ; Microbial Sensitivity Tests ; Mutation ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development ; }, abstract = {BACKGROUND: Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm.

OBJECTIVES: To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm.

METHODS: The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time-kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined.

RESULTS: In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant.

CONCLUSIONS: The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.}, } @article {pmid31423363, year = {2019}, author = {Payette, G and Geoffroy, V and Martineau, C and Villemur, R}, title = {Dynamics of a methanol-fed marine denitrifying biofilm: 1-Impact of environmental changes on the denitrification and the co-occurrence of Methylophaga nitratireducenticrescens and Hyphomicrobium nitrativorans.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e7497}, pmid = {31423363}, issn = {2167-8359}, abstract = {BACKGROUND: The biofilm of a methanol-fed denitrification system that treated a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans strain NL23 and Methylophaga nitratireducenticrescens strain JAM1 are the principal bacteria involved in the denitrifying activities. Here, we report the capacity of the denitrifying biofilm to sustain environmental changes, and the impact of these changes on the co-occurrence of H. nitrativorans and M. nitratireducenticrescens.

METHODS: In a first set of assays, the original biofilm (OB) was cultivated in an artificial seawater (ASW) medium under anoxic conditions to colonize new carriers. The new formed biofilm was then subjected to short exposures (1-5 days) of a range of NaCl, methanol, nitrate (NO3 [-]) and nitrite (NO2 [-]) concentrations, and to different pHs and temperatures. In a second set of assays, the OB was cultivated in ASW medium for five weeks with (i) a range of NaCl concentrations, (ii) four combinations of NO3 [-]/methanol concentrations and temperatures, (iii) NO2 [-], and (iv) under oxic conditions. Finally, the OB was cultivated for five weeks in the commercial Instant Ocean (IO) seawater. The growth of the biofilm and the dynamics of NO3 [-] and NO2 [-] were determined. The levels of M. nitratireducenticrescens and H. nitrativorans were measured by qPCR.

RESULTS: In the first set of assays, the biofilm cultures had the capacity to sustain denitrifying activities in most of the tested conditions. Inhibition occurred when they were exposed to high pH (10) or to high methanol concentration (1.5%). In the second set of assays, the highest specific denitrification rates occurred with the biofilm cultures cultivated at 64.3 mM NO3 [-] and 0.45% methanol, and at 30 °C. Poor biofilm development occurred with the biofilm cultures cultivated at 5% and 8% NaCl. In all biofilm cultures cultivated in ASW at 2.75% NaCl, H. nitrativorans strain NL23 decreased by three orders of magnitude in concentrations compared to that found in OB. This decrease coincided with the increase of the same magnitude of a subpopulation of M. nitratireducenticrescens (strain GP59 as representative). In the biofilm cultures cultivated at low NaCl concentrations (0% to 1.0%), persistence of H. nitrativorans strain NL23 was observed, with the gradual increase in concentrations of M. nitratireducenticrescens strain GP59. High levels of H. nitrativorans strain NL23 were found in the IO biofilm cultures. The concentrations of M. nitratireducenticrescens strain JAM1 were lower in most of the biofilms cultures than in OB.

CONCLUSIONS: These results demonstrate the plasticity of the marine methylotrophic denitrifying biofilm in adapting to different environmental changes. The NaCl concentration is a crucial factor in the dynamics of H. nitrativorans strain NL23, for which growth was impaired above 1% NaCl in the ASW-based biofilm cultures in favor of M. nitratireducenticrescens strain GP59.}, } @article {pmid31423359, year = {2019}, author = {Villemur, R and Payette, G and Geoffroy, V and Mauffrey, F and Martineau, C}, title = {Dynamics of a methanol-fed marine denitrifying biofilm: 2-impact of environmental changes on the microbial community.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e7467}, pmid = {31423359}, issn = {2167-8359}, abstract = {BACKGROUND: The biofilm of a methanol-fed, marine denitrification system is composed of a multi-species microbial community, among which Hyphomicrobium nitrativorans and Methylophaga nitratireducenticrescens are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm was cultivated in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific environmental conditions. We previously reported the impact of these changes on the denitrifying activities and the co-occurrence of H. nitrativorans strain NL23 and M. nitratireducenticrescens in the biofilm cultures. Here, we report the impact of these changes on the dynamics of the overall microbial community of the denitrifying biofilm.

METHODS: The original biofilm (OB) taken from the denitrification system was cultivated in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate/methanol concentrations and temperatures. The OB was also cultivated in the commercial Instant Ocean seawater (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA gene sequences. Culture approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of selected biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures of H. nitrativorans strain NL23 and M. nitratireducenticrescens strain GP59.

RESULTS: High proportions of M. nitratireducenticrescens occurred in the biofilm cultures. H. nitrativorans strain NL23 was found in high proportion in the OB, but was absent in the biofilm cultures cultivated in the ASW medium at 2.75% NaCl. It was found however in low proportions in the biofilm cultures cultivated in the ASW medium at 0-1% NaCl and in the IO biofilm cultures. Denitrifying bacterial isolates affiliated to Marinobacter spp. and Paracoccus spp. were isolated. Up regulation of the denitrification genes of strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to the Stappia spp. were metabolically active in the biofilm cultures.

CONCLUSIONS: These results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes of M. nitratireducenticrescens strain GP59 and H. nitrativorans strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm. Other denitrifying heterotrophic bacteria are present in low proportions, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.}, } @article {pmid31421719, year = {2019}, author = {Velmourougane, K and Prasanna, R and Supriya, P and Ramakrishnan, B and Thapa, S and Saxena, AK}, title = {Transcriptome profiling provides insights into regulatory factors involved in Trichoderma viride-Azotobacter chroococcum biofilm formation.}, journal = {Microbiological research}, volume = {227}, number = {}, pages = {126292}, doi = {10.1016/j.micres.2019.06.002}, pmid = {31421719}, issn = {1618-0623}, mesh = {Azotobacter/*genetics ; Biofilms/*growth & development ; Coculture Techniques ; Down-Regulation ; *Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Gene Expression Regulation, Fungal ; Genes, Bacterial/genetics ; Genes, Fungal/genetics ; Microbial Interactions/*genetics/physiology ; Plant Development ; Plants/microbiology ; *Transcriptome ; Trichoderma/*genetics ; Up-Regulation ; }, abstract = {Azotobacter chroococcum (Az) and Trichoderma viride (Tv) represent agriculturally important and beneficial plant growth promoting options which contribute towards nutrient management and biocontrol, respectively. When Az and Tv are co-cultured, they form a biofilm, which has proved promising as an inoculant in several crops; however, the basic aspects related to regulation of biofilm formation were not investigated. Therefore, whole transcriptome sequencing (Illumina NextSeq500) and gene expression analyses were undertaken, related to biofilm formation vis a vis Tv and Az growing individually. Significant changes in the transcriptome profiles of biofilm were recorded and validated through qPCR analyses. In-depth evaluation also identified several genes (phoA, phoB, glgP, alg8, sipW, purB, pssA, fadD) specifically involved in biofilm formation in Az, Tv and Tv-Az. Genes coding for RNA-dependent RNA polymerase, ABC transporters, translation elongation factor EF-1, molecular chaperones and double homeobox 4 were either up-regulated or down-regulated during biofilm formation. To our knowledge, this is the first report on the modulation of gene expression in an agriculturally beneficial association, as a biofilm. Our results provide insights into the regulatory factors involved during biofilm formation, which can help to improve the beneficial effects and develop more effective and promising plant- microbe associations.}, } @article {pmid31421577, year = {2019}, author = {Song, W and Qi, R and Zhao, L and Xue, N and Wang, L and Yang, Y}, title = {Bacterial community rather than metals shaping metal resistance genes in water, sediment and biofilm in lakes from arid northwestern China.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {254}, number = {Pt A}, pages = {113041}, doi = {10.1016/j.envpol.2019.113041}, pmid = {31421577}, issn = {1873-6424}, mesh = {Bacteria/genetics ; Biofilms ; China ; *Environmental Monitoring ; Geologic Sediments/chemistry ; Lakes/chemistry/*microbiology ; Metals, Heavy/*analysis ; *Microbiota ; Proteobacteria/genetics ; RNA, Ribosomal, 16S/genetics ; Water ; *Water Microbiology ; Water Pollutants, Chemical/*analysis ; }, abstract = {Lakes in arid northwestern China are valuable freshwater resources that drive socioeconomic development. Environmental pollution can significantly influence the composition of microbial communities and the distribution of functional genes in lakes. This study investigated heavy metal pollution to identify possible correlations with metal resistance genes (MRGs) and bacterial community composition in water, sediment and biofilm samples from Bosten Lake and Ebi Lake in northwestern China. High levels of zinc were detected in all samples. However, the metals detected in the sediment samples of both lakes were determined to be at low risk levels according to an ecological index. The mercury resistance gene subtype merP had the greatest average abundance (4.61 × 10[-3] copies per 16S rRNA) among all the samples, followed by merA and merC. The high abundance of merA in the pelagic zone rather than in benthic sediment suggests that the pelagic microbial community was important in mercury reduction. Proteobacteria were the main phylum found in the microbial communities in all samples. However, microbial communities in most of the water, sediment and biofilm samples had different compositions, indicating that the habitat niche plays an important role in shaping the bacterial communities in lakes. The microbial community, rather than the heavy metals, was the main driver of MRG distribution. The abundances of some bacterial genera involved in the decomposition of organic matter and the terrestrial nitrogen cycle were negatively correlated with heavy metals. This result suggests that metal pollution can adversely affect the biogeochemical processes that occur in lakes.}, } @article {pmid31421576, year = {2019}, author = {Lukwambe, B and Zhao, L and Nicholaus, R and Yang, W and Zhu, J and Zheng, Z}, title = {Bacterioplankton community in response to biological filters (clam, biofilm, and macrophytes) in an integrated aquaculture wastewater bioremediation system.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {254}, number = {Pt A}, pages = {113035}, doi = {10.1016/j.envpol.2019.113035}, pmid = {31421576}, issn = {1873-6424}, mesh = {Animals ; *Aquaculture ; Aquatic Organisms/metabolism ; *Biodegradation, Environmental ; Biofilms ; Bivalvia/metabolism ; Denitrification ; Nitrates ; Nitrification ; Nitrogen/analysis ; Phosphorus/metabolism ; Plankton/physiology ; Waste Disposal, Fluid/*methods ; Wastewater ; }, abstract = {Integrated systems with appropriate bio-filters can be used to treat aquaculture effluents. However, the information on bio-filters that alters the ecological functions of the bacterioplankton community (BC) in biodegradation of the aquaculture effluents remains controversial. In this study, we implemented a comprehensive restoration technology combined with bio-filters [biofilm, clam (Tegillarca granosa), and macrophytes (Spartina anglica)] to investigate their influence on the stability of the BC and nutrient removal. We found that the diversity of BC was linked with biogeochemical factors in processing and upcycling nitrogen-rich effluents into high-value biomass. The BC exhibited significant distinct patterns in the bio-filter areas. Potential biomarkers for constrained harmfully algae-bacteria (Nitriliruptoraceae, Bacillales, and Rhodobacteraceae) and nutrient removal were significantly higher in the bio-filters areas. The bio-filters significantly promoted the restoration effects of N and P balance by reducing 82.34% of total nitrogen (TN) and 81.64% of total phosphorus (TP) loads at the water interface. The main mechanisms for TN and TP removal and nutrient transformation were achieved by assimilation and absorption by the emergent macrophytes (Spartina anglica). The bio-filters significantly influenced the biodegradability and resolvability of particulate organic matter through ammonification, nitrification, and denitrification of microbes, which meliorated the nutrient removal. Beside bio-filter effects, the BC was significantly controlled by abiotic factors [nitrate (NO3[-]-N), dissolved oxygen (DO), total nitrogen (TN), and water temperature (WT)], and biotic factors (chlorophyll ɑ and green algae). Our study revealed that the co-existence system with bio-filters may greatly improve our understanding on the ecological functions of the BC in aquaculture systems. Overall, combined bio-filters provide an opportunity for the development of efficient and optimized aquaculture wastewater treatment technology.}, } @article {pmid31421403, year = {2019}, author = {Martín, ML and Dassie, SA and Valenti, LE and Giacomelli, CE}, title = {A simple surface biofunctionalization strategy to inhibit the biofilm formation by Staphylococcus aureus on solid substrates.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {183}, number = {}, pages = {110432}, doi = {10.1016/j.colsurfb.2019.110432}, pmid = {31421403}, issn = {1873-4367}, mesh = {Adsorption ; Bacterial Adhesion/drug effects/*physiology ; Biofilms/*growth & development ; Cell Wall/*metabolism ; Fibrinogen/chemistry/*metabolism/pharmacology ; Protein Binding ; Staphylococcal Infections/microbiology/prevention & control ; Staphylococcus aureus/*physiology ; Surface Properties ; }, abstract = {Staphylococcus aureus is an important opportunistic pathogen that causes a broad range of infections due to the bacteria capacity to form biofilms on medical devices. This work is aimed at inhibiting the biofilm formation by S. aureus on solid substrates using a simple surface biofunctionalization strategy. We previously found that surface biofunctionalization with structural perturbed albumin inhibited the initial stage of S. aureus adhesion. The current work extends this strategy with other plasma protein, fibrinogen, which in addition can be bond specifically to the cell wall-anchored proteins of S. aureus. The study of fibrinogen adsorption indicates that the fraction of surface-perturbed molecules is enlarged at long adsorption times and low protein concentration. In these conditions, a significant diminution of ca.60% of alive adhered bacteria were observed after 40 min and the biofilm formation was completely prevented. Thus, it seems that the inhibition of bacterial adhesion on substrates with surface-perturbed proteins represents a general trend even when specific interactions are present. On this basis, we developed a simple strategy to inhibit the formation of S. aureus biofilm, using thermally treated albumin or fibrinogen molecules prior to the substrate biofunctionalization. This strategy shows an excellent performance since the alive adhered bacteria diminishes ca. 90% at short incubation time, followed by the fully inhibition of biofilm formation. This novel and simple resource represents a change of the usual notion in avoiding post-surgery infections, mostly related to the use of medical devices.}, } @article {pmid31420537, year = {2019}, author = {Qin, Y and He, Y and She, Q and Larese-Casanova, P and Li, P and Chai, Y}, title = {Heterogeneity in respiratory electron transfer and adaptive iron utilization in a bacterial biofilm.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {3702}, pmid = {31420537}, issn = {2041-1723}, mesh = {Bacillus subtilis/*metabolism ; Bacterial Proteins/metabolism ; *Biofilms ; Citric Acid Cycle ; *Electron Transport ; Glycolysis ; Hydroxybenzoates/*metabolism ; Iron/*metabolism ; Membrane Potentials ; Oligopeptides/metabolism ; Repressor Proteins/metabolism ; Siderophores/biosynthesis ; }, abstract = {In Bacillus subtilis, robust biofilm formation requires large quantities of ferric iron. Here we show that this process requires preferential production of a siderophore precursor, 2,3-dihydroxybenzoate, instead of the siderophore bacillibactin. A large proportion of iron is associated extracellularly with the biofilm matrix. The biofilms are conductive, with extracellular iron potentially acting as electron acceptor. A relatively small proportion of ferric iron is internalized and boosts production of iron-containing enzymes involved in respiratory electron transfer and establishing strong membrane potential, which is key to biofilm matrix production. Our study highlights metabolic diversity and versatile energy generation strategies within B. subtilis biofilms.}, } @article {pmid31420126, year = {2019}, author = {Fulaz, S and Vitale, S and Quinn, L and Casey, E}, title = {Nanoparticle-Biofilm Interactions: The Role of the EPS Matrix.}, journal = {Trends in microbiology}, volume = {27}, number = {11}, pages = {915-926}, doi = {10.1016/j.tim.2019.07.004}, pmid = {31420126}, issn = {1878-4380}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Extracellular Polymeric Substance Matrix/*drug effects ; *Nanoparticles ; }, abstract = {The negative consequences of biofilms are widely reported. A defining feature of biofilms is the extracellular matrix, a complex mixture of biomacromolecules, termed EPS, which contributes to reduced antimicrobial susceptibility. EPS targeting is a promising, but underexploited, approach to biofilm control allowing disruption of the matrix and thereby increasing the susceptibility to antimicrobials. Nanoparticles (NPs) can play a very important role as 'carriers' of EPS matrix disruptors, and several approaches have recently been proposed. In this review, we discuss the application of nanoparticles as antibiofilm technologies with a special emphasis on the role of the EPS matrix in the physicochemical regulation of the nanoparticle-biofilm interaction. We highlight the use of nanoparticles as a platform for a new generation of antibiofilm approaches.}, } @article {pmid31419460, year = {2019}, author = {Miryala, SK and Anbarasu, A and Ramaiah, S}, title = {Systems biology studies in Pseudomonas aeruginosa PA01 to understand their role in biofilm formation and multidrug efflux pumps.}, journal = {Microbial pathogenesis}, volume = {136}, number = {}, pages = {103668}, doi = {10.1016/j.micpath.2019.103668}, pmid = {31419460}, issn = {1096-1208}, mesh = {Biofilms/*growth & development ; *Biological Transport, Active ; *Drug Resistance, Multiple, Bacterial ; Gene Regulatory Networks ; Protein Interaction Maps ; Pseudomonas aeruginosa/*enzymology/genetics/*growth & development ; Systems Biology ; }, abstract = {The antimicrobial resistance (AMR) exhibited against broad spectrum and new generation antibiotics used for Pseudomonas infections is a major threat and renders the treatment ineffective. In our present study, we have used a computational approach to understand various drug resistance mechanisms which contribute to Multi-Drug Resistance (MDR) in P. aeruginosa. The interaction network of 60 AMR genes along with the 337 functional interactions was analyzed. Functional enrichment analysis of AMR genes has shown that the genes in the network are mainly associated with efflux pump mechanisms, alginate biosynthesis, biofilm formation, and ampC beta-lactamase biosynthesis. Interestingly, the genes phoP, phoQ, and cat genes are observed to have roles in more than one drug-resistant mechanism. The genes phoP and phoQ apart from their role in two-component regulatory systems also play major roles in multidrug efflux pumps and alteration in drug target. The gene cat involves in alteration of drug target and enzymatic inactivation. The interaction network analysis has shown that the AMR genes oprJ, oprM, oprN, ampC, gyrA, mexA, oprD, mexB and nfxB have higher number of direct interactors and they are considered as the hub nodes in the network and these genes can be used as potential drug targets for developing new drugs. The results from our study will be helpful in better understanding of the antibiotic resistance mechanisms in P. aeruginosa. The gene targets reported, can be used for new drug discovery against Pseudomonas infections.}, } @article {pmid31413280, year = {2019}, author = {Inui, T and Palmer, RJ and Shah, N and Li, W and Cisar, JO and Wu, CD}, title = {Effect of mechanically stimulated saliva on initial human dental biofilm formation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {11805}, pmid = {31413280}, issn = {2045-2322}, mesh = {*Biofilms ; Humans ; Mouth/*microbiology ; *Saliva ; Streptococcus/classification/isolation & purification/physiology ; }, abstract = {This study evaluated the impact of mechanically stimulated saliva on initial bacterial colonization. Interaction between oral bacteria and both unstimulated and stimulated saliva was examined in vitro by laying labeled bacteria over SDS-PAGE-separated salivary proteins. The effects of chewing on in vivo biofilm, microbial composition, and spatial arrangement were examined in two human volunteers using an intraoral stent containing retrievable enamel chips. In vitro experiments showed that bacterial binding to proteins from stimulated saliva was lower than that to proteins from unstimulated saliva. Lack of binding activity was noted with Streptococcus mutans and Lactobacillus casei. Human Oral Microbe Identification Microarray (HOMIM) analyses revealed a consistent chewing-related increase in the binding of Streptococcus anginosus and Streptococcus gordonii. Immunofluorescence microscopy demonstrated the presence of multi-species colonies and cells bearing different serotypes of the coaggregation-mediating streptococcal cell-surface receptor polysaccharides (RPS). Differences in bacterial colonization were noted between the two volunteers, while the type 4 RPS-reactive serotype was absent in one volunteer. Cells reacting with antibody against Rothia or Haemophilus were prominent in the early biofilm. While analysis of the data obtained demonstrated inter-individual variations in both in vitro and in vivo bacterial binding patterns, stimulating saliva with multiple orosensory stimuli may modulate oral bacterial colonization of tooth surfaces.}, } @article {pmid31412645, year = {2019}, author = {Magin, V and Garrec, N and Andrés, Y}, title = {Selection of Bacteriophages to Control In Vitro 24 h Old Biofilm of Pseudomonas Aeruginosa Isolated from Drinking and Thermal Water.}, journal = {Viruses}, volume = {11}, number = {8}, pages = {}, pmid = {31412645}, issn = {1999-4915}, mesh = {Bacteriophages/genetics/isolation & purification/*physiology ; *Biofilms ; Colony Count, Microbial ; Drinking Water/chemistry/*microbiology ; Host Specificity ; Hot Temperature ; Pseudomonas aeruginosa/growth & development/physiology/*virology ; Stainless Steel/analysis ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes public healthcare issues. In moist environments, this Gram-negative bacterium persists through biofilm-associated contamination on surfaces. Bacteriophages are seen as a promising alternative strategy to chemical biocides. This study evaluates the potential of nine lytic bacteriophages as biocontrol treatments against nine environmental P. aerginosa isolates. The spot test method is preliminarily used to define the host range of each virus and to identify their minimum infectious titer, depending on the strain. Based on these results, newly isolated bacteriophages 14.1, LUZ7, and B1 are selected and assessed on a planktonic cell culture of the most susceptible isolates (strains MLM, D1, ST395E, and PAO1). All liquid infection assays are achieved in a mineral minimum medium that is much more representative of real moist environments than standard culture medium. Phages 14.1 and LUZ7 eliminate up to 90% of the PAO1 and D1 bacterial strains. Hence, their effectiveness is evaluated on the 24 h old biofilms of these strains, established on a stainless steel coupon that is characteristic of materials found in thermal and industrial environments. The results of quantitative PCR viability show a maximum reduction of 1.7 equivalent Log CFU/cm[2] in the coupon between treated and untreated surfaces and shed light on the importance of considering the entire virus/host/environment system for optimizing the treatment.}, } @article {pmid31411265, year = {2019}, author = {Yu, MK and Kim, MA and Rosa, V and Hwang, YC and Del Fabbro, M and Sohn, WJ and Min, KS}, title = {Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite.}, journal = {Journal of applied oral science : revista FOB}, volume = {27}, number = {}, pages = {e20180699}, pmid = {31411265}, issn = {1678-7765}, mesh = {Animals ; Biofilms/*drug effects/*growth & development ; Cattle ; Colony Count, Microbial ; DNA, Bacterial/*pharmacology ; Dental Pulp Cavity/microbiology ; Deoxyribonucleases/*pharmacology ; Enterococcus faecalis/*drug effects/*growth & development ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/isolation & purification ; Reproducibility of Results ; Sodium Hypochlorite/*pharmacology ; Time Factors ; }, abstract = {OBJECTIVE: This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis (E. faecalis) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl).

METHODOLOGY: E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting.

RESULTS: CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05).

CONCLUSIONS: Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.}, } @article {pmid31410982, year = {2019}, author = {Petrovich, ML and Ben Maamar, S and Hartmann, EM and Murphy, BT and Poretsky, RS and Wells, GF}, title = {Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants.}, journal = {Microbial biotechnology}, volume = {12}, number = {6}, pages = {1324-1336}, pmid = {31410982}, issn = {1751-7915}, mesh = {Biofilms/*growth & development ; Bioreactors/*virology ; *Metagenome ; Myoviridae/*classification/genetics ; Podoviridae/*classification/genetics ; Siphoviridae/*classification/genetics ; Wastewater/microbiology/*virology ; Water Purification ; }, abstract = {Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.}, } @article {pmid31410606, year = {2019}, author = {Wang, Z and Shi, LD and Lai, CY and Zhao, HP}, title = {Methane oxidation coupled to vanadate reduction in a membrane biofilm batch reactor under hypoxic condition.}, journal = {Biodegradation}, volume = {30}, number = {5-6}, pages = {457-466}, doi = {10.1007/s10532-019-09887-6}, pmid = {31410606}, issn = {1572-9729}, mesh = {Anaerobiosis ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; *Methane ; Oxidation-Reduction ; *Vanadates ; }, abstract = {This study shows vanadate (V(V)) reduction in a methane (CH4) based membrane biofilm batch reactor when the concentration of dissolved oxygen (O2) was extremely low. V(IV) was the dominant products formed from V(V) bio-reduction, and majority of produced V(IV) transformed into precipitates with green color. Quantitative polymerase chain reaction and Illumina sequencing analysis showed that archaea methanosarcina were significantly enriched. Metagenomic predictive analysis further showed the enrichment of genes associated with reverse methanogenesis pathway, the key CH4-activating mechanism for anaerobic methane oxidation (AnMO), as well as the enrichment of genes related to acetate synthesis, in archaea. The enrichment of aerobic methanotrophs Methylococcus and Methylomonas implied their role in CH4 activation using trace level of O2, or their participation in V(V) reduction.}, } @article {pmid31410037, year = {2019}, author = {Bidossi, A and Bottagisio, M and De Grandi, R and Drago, L and De Vecchi, E}, title = {Chlorquinaldol, a topical agent for skin and wound infections: anti-biofilm activity and biofilm-related antimicrobial cross-resistance.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {2177-2189}, pmid = {31410037}, issn = {1178-6973}, abstract = {PURPOSE: Persistence of skin and wound infections is nowadays accepted being linked to bacterial biofilms, which are highly recalcitrant to treatments and contribute to maintain a constant inflammation state and prevent a correct healing. Topical antimicrobials are the most common first-line self-medications; however, treatment failure is not uncommon and emerging resistance to antibiotics is alarming. Chlorquinaldol is an antimicrobial with a wide spectrum of activity and desirable characteristics for topical application. Aim of this study was to evaluate the efficacy of chlorquinaldol to prevent or eradicate S. aureus and P. aeruginosa biofilms, in comparison to classic topical antibiotics like gentamicin and fusidic acid.

METHODS: Minimum inhibitory concentrations (MIC) were assessed for each strain and subinhibitory concentrations (½ and ¼ MIC) were used in the biofilm assay. Antimicrobial assays were performed during biofilm formation or were applied on mature biofilms and were evaluated by means of crystal violet assay and confocal laser scan microscopy.

RESULTS: Chlorquinaldol and gentamicin were the most effective antimicrobials in both eradicating and preventing pathogens biofilm; however, resistance to methicillin and impermeability to carbapenems impaired chlorquinaldol effect. In addition, similarly to other hydroxyquinolines, aspecific metal chelation is here proposed as chlorquinaldol mode of action.

CONCLUSION: Relying on an acceptable antibiofilm and a wide spectrum of activity, an aspecific mode of action and consequent absence of resistance development, chlorquinaldol proved to be a good antimicrobial for topical use.}, } @article {pmid31409687, year = {2019}, author = {Jung, YC and Lee, MA and Lee, KH}, title = {Role of Flagellin-Homologous Proteins in Biofilm Formation by Pathogenic Vibrio Species.}, journal = {mBio}, volume = {10}, number = {4}, pages = {}, pmid = {31409687}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/metabolism ; Flagella/genetics/metabolism ; Flagellin/genetics/*metabolism ; Locomotion ; Mutation ; Open Reading Frames ; Polysaccharides, Bacterial/genetics/metabolism ; Secretory Pathway ; Transcription, Genetic ; Vibrio/genetics/*pathogenicity/*physiology ; Vibrio vulnificus/genetics/pathogenicity/physiology ; }, abstract = {The pathogenic bacterium Vibrio vulnificus exhibits the ability to form biofilm, for which initiation is dependent upon swimming motility by virtue of a polar flagellum. The filament of its flagellum is composed of multiple flagellin subunits, FlaA, -B, -C, and -D. In V. vulnificus genomes, however, open reading frames (ORFs) annotated by FlaE and -F are also present. Although neither FlaE nor FlaF is involved in filament formation and cellular motility, they are well expressed and secreted to the extracellular milieu through the secretion apparatus for flagellar assembly. In the extrapolymeric matrix of V. vulnificus biofilm, significant levels of FlaEF were detected. Mutants defective in both flaE and flaF formed significantly decreased biofilms compared to the wild-type biofilm. Thus, the potential role of FlaEF during the biofilm-forming process was investigated by exogenous addition of recombinant FlaEF (rFlaEF) to the biofilm assays. The added rFlaE and rFlaF were predominantly incorporated into the biofilm matrix formed by the wild type. However, biofilms formed by a mutant defective in exopolysaccharide (EPS) biosynthesis were not affected by added FlaEF. These results raised a possibility that FlaEF specifically interact with EPS within the biofilm matrix. In vitro pulldown assays using His-tagged rFlaEF or rFlaC revealed the specific binding of EPS to rFlaEF but not to rFlaC. Taken together, our results demonstrate that V. vulnificus FlaEF, flagellin-homologous proteins (FHPs), are crucial for biofilm formation by directly interacting with the essential determinant for biofilm maturation, EPS. Further analyses performed with other pathogenic Vibrio species demonstrated both the presence of FHPs and their important role in biofilm formation.IMPORTANCE Flagellar filaments of the pathogenic Vibrio species, including V. vulnificus, V. parahaemolyticus, and V. cholerae, are composed of multiple flagellin subunits. In their genomes, however, there are higher numbers of the ORFs encoding flagellin-like proteins than the numbers of flagellin subunits required for filament assembly. Since these flagellin-homologous proteins (FHPs) are well expressed and excreted to environments via a flagellin transport channel, their extracellular role in the pathogenic Vibrio has been enigmatic. Their biological significance, which is not related with flagellar functions, has been revealed to be in maturation of biofilm structures. Among various components of the extracellular polymeric matrix produced in the V. vulnificus biofilms, the exopolysaccharides (EPS) are dominant constituents and crucial in maturation of biofilms. The enhancing role of the V. vulnificus FHPs in biofilm formation requires the presence of EPS, as indicated by highly specific interactions among two FHPs and three EPS.}, } @article {pmid31408199, year = {2020}, author = {Ali, IAA and Cheung, BPK and Yau, JYY and Matinlinna, JP and Lévesque, CM and Belibasakis, GN and Neelakantan, P}, title = {The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms.}, journal = {International endodontic journal}, volume = {53}, number = {1}, pages = {53-61}, doi = {10.1111/iej.13202}, pmid = {31408199}, issn = {1365-2591}, support = {201702159011//University Research Committee, University of Hong Kong/ ; }, mesh = {*Biofilms ; *Enterococcus faecalis ; Microscopy, Confocal ; }, abstract = {AIM: To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism.

METHODOLOGY: Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3-day and 21-day-old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture-dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony-forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05).

RESULTS: Collagen conditioning significantly increased the number of CFUs in the 21-day biofilms, compared to the 3-day biofilms (P < 0.05). Although the biochemical analysis revealed that surface conditioning had no significant effect on the total carbohydrate content in the 21-day biofilms, confocal microscopic analysis revealed that collagen and saliva conditioning selectively increased the polysaccharide content of 21-day biofilms, compared to the 3-day biofilms (P < 0.05).

CONCLUSIONS: The results of this study raise an important methodological concern that the substrate conditioning substances and biofilm age differentially influence the cellular and extracellular matrix components of E. faecalis biofilms.}, } @article {pmid31407877, year = {2019}, author = {Nie, L and Li, Y and Chen, S and Li, K and Huang, Y and Zhu, Y and Sun, Z and Zhang, J and He, Y and Cui, M and Wei, S and Qiu, F and Zhong, C and Liu, W}, title = {Biofilm Nanofiber-Coated Separators for Dendrite-Free Lithium Metal Anode and Ultrahigh-Rate Lithium Batteries.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {35}, pages = {32373-32380}, doi = {10.1021/acsami.9b08656}, pmid = {31407877}, issn = {1944-8252}, abstract = {Rechargeable batteries that combine high energy density with high power density are highly demanded. However, the wide utilization of lithium metal anode is limited by the uncontrollable dendrite growth, and the conventional lithium-ion batteries (LIBs) commonly suffer from low rate capability. Here, we for the first time develop a biofilm-coated separator for high-energy and high-power batteries. It reveals that the coating of Escherichia coli protein nanofibers can improve electrolyte wettability and lithium transference number and enhance adhesion between separators and electrodes. Thus, lithium dendrite growth is impeded because of the uniform distribution of the Li-ion flux. The modified separator also enables the stable cycling of high-voltage Li|Li1.2Mn0.6Ni0.2O2 (LNMO) cells at an extremely high rate of 20 C, delivering a high specific capacity of 83.1 mA h g[-1], which exceeds the conventional counterpart. In addition, the modified separator in the Li4Ti5O12|LNMO full cell also exhibits a larger capacity of 68.2 mA h g[-1] at 10 C than the uncoated separator of 37.4 mA h g[-1]. Such remarkable performances of the modified separators arise from the conformal, adhesive, and endurable coating of biofilm nanofibers. Our work opens up a new opportunity for protein-based biomaterials in practical application of high-energy and high-power batteries.}, } @article {pmid31407437, year = {2019}, author = {Daubert, DM and Weinstein, BF}, title = {Biofilm as a risk factor in implant treatment.}, journal = {Periodontology 2000}, volume = {81}, number = {1}, pages = {29-40}, doi = {10.1111/prd.12280}, pmid = {31407437}, issn = {1600-0757}, mesh = {Biofilms ; *Dental Implants ; Humans ; *Peri-Implantitis ; Risk Factors ; *Stomatitis ; }, abstract = {This article summarizes the microbiological findings at dental implants, drawing distinctions between the peri-implant microbiome and the periodontal microbiome, and summarizes what is known regarding biofilm as a risk factor for specific stages of implant treatment. Targeted microbial analysis is reviewed as well as the latest results from open-ended sequencing of the peri-implant flora. At this time there remains a lack of consensus for a specific microbial profile that is associated with peri-implantitis, suggesting that there may be other factors which influence the microbiome such as titanium surface dissolution. Therapeutic interventions to address the biofilm are presented at the preoperative, perioperative, and postoperative stages. Evidence supports that perioperative chlorhexidine reduces biofilm-related implant complications and failure. Regular maintenance for dental implants is also shown to reduce peri-implant mucositis and implant failure. Maintenance procedures should aim to disrupt the biofilm without damaging the titanium dioxide surface layer in an effort to prevent further oxidation. Evidence supports the use of glycine powder air polishing as a valuable adjunct to conventional therapies for use at implant maintenance visits. For the treatment of peri-implantitis, nonsurgical therapy has not been shown to be effective, and while surgical intervention is not always predictable, it has been shown to be superior to nonsurgical treatment for decontamination of the implant surface that is not covered by bone.}, } @article {pmid31406097, year = {2019}, author = {Saad, A and Nikaido, T and Abdou, A and Matin, K and Burrow, MF and Tagami, J}, title = {Inhibitory effect of zinc-containing desensitizer on bacterial biofilm formation and root dentin demineralization.}, journal = {Dental materials journal}, volume = {38}, number = {6}, pages = {940-946}, doi = {10.4012/dmj.2018-352}, pmid = {31406097}, issn = {1881-1361}, mesh = {Animals ; Biofilms ; Cattle ; Dentin ; Streptococcus mutans ; *Tooth Demineralization ; *Zinc ; }, abstract = {This study compared the effect of a novel zinc containing, Caredyne Shield (CS), and a fluoroaluminocalciumsilicate-based, Nanoseal (NS) desensitizers on dentin tubule occlusion, inhibition of Streptococcus mutans (S. mutans) biofilm growth, and resistance to bacterial demineralization. Desensitizers were applied to simulated hypersensitive bovine dentin, with distilled water used as a control. S. mutans biofilms were grown on the surface of each specimen in an oral biofilm simulator. CS showed the least bacterial count and water insoluble glucan amount followed by NS. Transverse micro radiography revealed that both CS and NS showed significant reduction in mineral loss and lesion depth of the associated lesion. Scanning electron micrographs showed that the two desensitizers formed obvious depositions on the dentin surfaces, occlusion of tubules and mineral tag formation.}, } @article {pmid31405860, year = {2019}, author = {Willems, HME and Stultz, JS and Coltrane, ME and Fortwendel, JP and Peters, BM}, title = {Disparate Candida albicans Biofilm Formation in Clinical Lipid Emulsions Due to Capric Acid-Mediated Inhibition.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {11}, pages = {}, pmid = {31405860}, issn = {1098-6596}, support = {R21 AI153768/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects ; Decanoic Acids/*pharmacology ; Emulsions/*pharmacology ; Fatty Acids/*pharmacology ; Humans ; Parenteral Nutrition/methods ; Phospholipids/pharmacology ; Soybean Oil/pharmacology ; }, abstract = {Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related bloodstream infections (CR-BSI) caused by fungi, including by the polymorphic fungus Candida albicans, which is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVCs). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans We observed that the lipid emulsions Intralipid and Omegaven both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited C. albicans biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid when supplemented with capric acid-a fatty acid present in Smoflipid but absent in Intralipid. Capric acid was also found to dose dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.}, } @article {pmid31405233, year = {2019}, author = {Kwiecińska-Piróg, J and Skowron, K and Bogiel, T and Białucha, A and Przekwas, J and Gospodarek-Komkowska, E}, title = {Vitamin C in the Presence of Sub-Inhibitory Concentration of Aminoglycosides and Fluoroquinolones Alters Proteus mirabilis Biofilm Inhibitory Rate.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {3}, pages = {}, pmid = {31405233}, issn = {2079-6382}, abstract = {Vitamin C has antimicrobial activity and is often used as an oral supplement accompanying antibiotic treatment in urinary tract infections (UTI). Proteus mirabilis is the third common species responsible for UTIs that are mostly treated with fluoroquinolones or aminoglycosides. Treatment of the UTI caused by P. mirabilis is problematic due to the ability to form biofilm on the urinary catheters. The aim of the study was to evaluate the influence of ascorbic acid in combination with antibiotics on P. mirabilis abilities to form biofilm. The susceptibility of P. mirabilis reference strain ATCC[®] 29906™ and four clinical strains isolated from the urine samples of patients with urinary catheter were evaluated according to EUCAST recommendations. The influence of ascorbic acid (0.4 mg × mL[-1]) in combination with antibiotics on biofilm formation was evaluated spectrophotometrically. Aminoglycosides at sub-inhibitory concentrations more successfully limited biofilm formation by P. mirabilis strains without ascorbic acid addition. Inhibition rate differences at the lowest concentrations of gentamicin and amikacin were statistically significant (p ≤ 0.05). Ascorbic acid addition to the culture medium limited the inhibitory effect of fluoroquinolones, facilitating biofilm formation by P. mirabilis strains. The addition of ascorbic acid during aminoglycosides therapy may disturb treatment of urinary tract infections related to the presence of P. mirabilis biofilm.}, } @article {pmid31405172, year = {2019}, author = {Guzzon, A and Di Pippo, F and Congestri, R}, title = {Wastewater Biofilm Photosynthesis in Photobioreactors.}, journal = {Microorganisms}, volume = {7}, number = {8}, pages = {}, pmid = {31405172}, issn = {2076-2607}, support = {QLK3-CT2002-01938//EC/ ; }, abstract = {Photosynthetic performance of algal-bacterial biofilms from an Italian wastewater treatment plant was studied in a flow-lane photobioreactor at different irradiances, temperatures, and flow regime to evaluate the effects of these environmental parameters on biofilms' functioning, in view of application of these communities in wastewater biological treatment. Pulse amplitude modulated fluorescence was used to estimate the effective quantum yield of PSII (ΔF/Fm') of the light-acclimated biofilms and to perform rapid light curves (RLCs) for the determination of the photosynthetic parameters (rel.ETRmax, α, Ik). Chl a, ash free dry weight (AFDW), and dry weight (DW) were measured to assess phototrophic and whole biofilm biomass development over time. From the analysis of photosynthetic parameter variation with light intensity, temperature and flow rate, it was possible to identify the set of experimental values favoring biofilm photosynthetic activity. Biomass increased over time, especially at the highest irradiances, where substrata were fastly colonized and mature biofilms developed at all temperatures and flow conditions tested.}, } @article {pmid31404843, year = {2019}, author = {Kłodzińska, SN and Wan, F and Jumaa, H and Sternberg, C and Rades, T and Nielsen, HM}, title = {Utilizing nanoparticles for improving anti-biofilm effects of azithromycin: A head-to-head comparison of modified hyaluronic acid nanogels and coated poly (lactic-co-glycolic acid) nanoparticles.}, journal = {Journal of colloid and interface science}, volume = {555}, number = {}, pages = {595-606}, doi = {10.1016/j.jcis.2019.08.006}, pmid = {31404843}, issn = {1095-7103}, mesh = {Azithromycin/chemistry/*pharmacology ; Biofilms/*drug effects ; Hyaluronic Acid/chemistry/*pharmacology ; Nanoparticles/*chemistry ; Particle Size ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry/*pharmacology ; Surface Properties ; }, abstract = {HYPOTHESIS: The widespread resistance of bacteria to traditional antibiotic treatments has expedited the search for novel therapies against these pathogens. The hypothesis of this work is that two distinctively different polymeric delivery systems, specifically D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles and octenyl succinic anhydride-modified low molecular weight hyaluronic acid (OSA-HA) nanogels may be used to substantially improve the properties of azithromycin, allowing its use for effective treatment of Pseudomonas aeruginosa biofilm infections.

EXPERIMENTS: Azithromycin was encapsulated in both delivery systems and the physicochemical properties of the loaded delivery systems, including size, surface charge and drug loading were evaluated. Additionally, particle interaction with a mucin layer, penetration into a bacterial biofilm, prevention of biofilm formation and eradication of pre-formed biofilms, the influence on production of virulence factors and bacterial motility as well as cytotoxicity towards hepatocytes and lung epithelial cells were compared head-to-head.

FINDINGS: The TPGS-PLGA nanoparticles noticeably improved the antimicrobial activity and the biofilm prevention activity of azithromycin whereas the OSA-HA nanogels showed reduced mucin interactions together with improved reduction of pre-formed biofilms and maintained the low eukaryotic cell cytotoxicity of azithromycin.}, } @article {pmid31404739, year = {2019}, author = {Sun, G and Wan, J and Sun, Y and Li, H and Chang, C and Wang, Y}, title = {Enhanced removal of nitrate and refractory organic pollutants from bio-treated coking wastewater using corncobs as carbon sources and biofilm carriers.}, journal = {Chemosphere}, volume = {237}, number = {}, pages = {124520}, doi = {10.1016/j.chemosphere.2019.124520}, pmid = {31404739}, issn = {1879-1298}, mesh = {*Biodegradation, Environmental ; Biofilms ; Bioreactors ; Carbon ; Coke/*analysis ; Environmental Pollutants ; Nitrates/*analysis/metabolism ; RNA, Ribosomal, 16S ; Recycling ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; Water Pollutants, Chemical/*analysis/metabolism ; Zea mays ; }, abstract = {The quality of the bio-treated coking wastewater (BTCW) is difficult to meet increasingly stringent coking wastewater discharge standards and future wastewater recycling needs. In this study, the pre-treatment process of BTCW was installed including the two up-flow fixed-bed bioreactors (UFBRs) which were separately filled with alkali-pretreated or no alkali-pretreated corncobs used as solid carbon sources as well as biofilm carriers. Results showed that this pre-treatment process could significantly improve the biodegradability of BTCW and increase the C/N ratio. Thus, over 90% of residual nitrate in BTCW were removed stably. Furthermore, GC-MS analysis confirmed that the typical refractory organic matters decreased significantly after UFBRs pre-treatment. High-throughput sequencing analysis using 16S rRNA demonstrated that dominant denitrifiers, fermentative bacteria and refractory-organic-pollutants-degrading bacteria co-existed inside the UFBRs system. Compared with no alkali-pretreated corncobs, alkali-pretreated corncobs provided more porous structure and much stable release of carbon to guarantee the growth and the quantity of the functional bacteria such as denitrifiers. This study indicated that the UFBRs filled with alkali-pretreated corncobs could be utilized as an effective alternative for the enhanced treatment of the BTCW.}, } @article {pmid31404326, year = {2019}, author = {Wang, S and Wang, Y and Wang, Y and Duan, Z and Ling, Z and Wu, W and Tong, S and Wang, H and Deng, S}, title = {Theaflavin-3,3'-Digallate Suppresses Biofilm Formation, Acid Production, and Acid Tolerance in Streptococcus mutans by Targeting Virulence Factors.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1705}, pmid = {31404326}, issn = {1664-302X}, abstract = {As one of the most important cariogenic pathogens, Streptococcus mutans has strong abilities to form biofilms, produce acid and tolerate acid. In present study, we found that theaflavin-3,3'-digallate (TF3) had an inhibitory effect on S. mutans UA159 in vitro. Visualized by field emission-scanning electron microscopy, the suppressed formation of S. mutans biofilms grown with TF3 at sub-inhibitory concentrations could be attributed to the reduced biofilm matrix, which was proven to contain glucans and extracellular DNA (eDNA). Glucan-reduced effect of TF3 was achieved by down-regulating expression levels of gtfB, gtfC, and gtfD encoding glucosyltransferases. Besides, TF3 reduced eDNA formation of S. mutans by negatively regulating lrgA, lrgB, and srtA, which govern cell autolysis and membrane vesicle components. Furthermore, TF3 also played vital roles in antagonizing preformed biofilms of S. mutans. Bactericidal effects of TF3 became significant when its concentrations increased more than twofold of minimum inhibitory concentration (MIC). Moreover, the capacities of S. mutans biofilms to produce acid and tolerate acid were significantly weakened by TF3 at MIC. Based on real-time PCR (RT-PCR) analysis, the mechanistic effects of TF3 were speculated to comprise the inhibition of enolase, lactate dehydrogenase, F-type ATPase and the agmatine deiminase system. Moreover, TF3 has been found to downregulate LytST, VicRK, and ComDE two component systems in S. mutans, which play critical roles in the regulatory network of virulence factors. Our present study found that TF3 could suppress the formation and cariogenic capacities of S. mutans biofilms, which will provide new strategies for anti-caries in the future.}, } @article {pmid31403663, year = {2019}, author = {Shafeeq, S and Pannanusorn, S and Elsharabasy, Y and Ramírez-Zavala, B and Morschhäuser, J and Römling, U}, title = {Impact of manganese on biofilm formation and cell morphology of Candida parapsilosis clinical isolates with different biofilm forming abilities.}, journal = {FEMS yeast research}, volume = {19}, number = {6}, pages = {}, pmid = {31403663}, issn = {1567-1364}, mesh = {Biofilms/drug effects/*growth & development ; Candida parapsilosis/cytology/*drug effects/growth & development ; Candidiasis/*microbiology ; Cations, Divalent/*pharmacology ; Cell Differentiation/drug effects ; Fungal Proteins/genetics/*metabolism ; Humans ; Hyphae/cytology/drug effects/growth & development ; Manganese/*pharmacology ; Sequence Deletion ; Transcription Factors/genetics/metabolism ; }, abstract = {The commensal species Candida parapsilosis is an emerging human pathogen that has the ability to form biofilms. In this study, we explored the impact of the divalent cations cobalt (Co2+), copper (Cu2+), iron (Fe3+), manganese (Mn2+), nickel (Ni2+) and zinc (Zn2+) on biofilm formation of clinical isolates of C. parapsilosis with no, low and high biofilm forming abilities at 30 and 37°C. All strains besides one isolate showed a concentration-dependent enhancement of biofilm formation at 30°C in the presence of Mn2+ with a maximum at 2 mM. The biofilm forming ability of no and low biofilm forming isolates was >2-fold enhanced in the presence of 2 mM Mn2+, while the effect in high biofilm forming isolate was significantly less pronounced. Of note, cells in the biofilms of no and low biofilm forming strains differentiated into yeast and pseudohyphal cells similar in morphology to high biofilm formers. The biofilm transcriptional activator BCR1 has a dual developmental role in the absence and presence of 2 mM Mn2+ as it promoted biofilm formation of no biofilm forming strains, and, surprisingly, suppressed cells of no biofilm forming strains to develop into pseudohyphae and/or hyphae. Thus, environmental conditions can significantly affect the amount of biofilm formation and cell morphology of C. parapsilosis with Mn2+ to overcome developmental blocks to trigger biofilm formation and to partially relieve BCR1 suppressed cell differentiation.}, } @article {pmid31402901, year = {2019}, author = {van Vugt, TAG and Arts, JJ and Geurts, JAP}, title = {Antibiotic-Loaded Polymethylmethacrylate Beads and Spacers in Treatment of Orthopedic Infections and the Role of Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1626}, pmid = {31402901}, issn = {1664-302X}, abstract = {Polymethylmethacrylate (PMMA) also referred as (acrylic) bone cement is a non-degradable biomaterial that has been used in clinical orthopedic practice for several decades. PMMA can be used in a plain formulation, but is often used in an antibiotic-loaded formulation in (primary and revision) arthroplasty and in treatment of orthopedic infections as prosthetic joint infections (PJI) and chronic osteomyelitis. In treatment of PJIs antibiotic-loaded PMMA is often used as a carrier material for local antibiotic delivery in addition to treatment with systemic antibiotics. In this case, the antibiotic-loaded PMMA is often used as a spacer or as a bead chain. Since the introduction of PMMA as an antibiotic carrier there is a tremendous amount of scientific and clinical papers published, which studied numerous different aspects of antibiotic-loaded PMMA. This paper will review the research regarding basic principles of antibiotic-loaded PMMA as mechanism of action, antibiotic-release capacities, choice of antibiotics and influences on mechanical properties of PMMA. Subsequently, concerns regarding the application of antibiotic-loaded PMMA, biofilm formation, antibiotic resistance and local or systemic toxicity will be discussed. In addition to these subjects, the role of antibiotic loaded PMMA in clinical treatment of PJIs and chronic osteomyelitis is discussed in the final part of this paper.}, } @article {pmid31402749, year = {2019}, author = {Krantz, GP and Lucas, K and Wunderlich, EL and Hoang, LT and Avci, R and Siuzdak, G and Fields, MW}, title = {Bulk phase resource ratio alters carbon steel corrosion rates and endogenously produced extracellular electron transfer mediators in a sulfate-reducing biofilm.}, journal = {Biofouling}, volume = {35}, number = {6}, pages = {669-683}, doi = {10.1080/08927014.2019.1646731}, pmid = {31402749}, issn = {1029-2454}, mesh = {*Biofilms ; Biofouling ; Biological Transport ; Corrosion ; Desulfovibrio/*physiology ; Electrons ; Oxidation-Reduction ; Steel/*chemistry ; Sulfates/metabolism ; }, abstract = {Desulfovibrio alaskensis G20 biofilms were cultivated on 316 steel, 1018 steel, or borosilicate glass under steady-state conditions in electron-acceptor limiting (EAL) and electron-donor limiting (EDL) conditions with lactate and sulfate in a defined medium. Increased corrosion was observed on 1018 steel under EDL conditions compared to 316 steel, and biofilms on 1018 carbon steel under the EDL condition had at least twofold higher corrosion rates compared to the EAL condition. Protecting the 1018 metal coupon from biofilm colonization significantly reduced corrosion, suggesting that the corrosion mechanism was enhanced through attachment between the material and the biofilm. Metabolomic mass spectrometry analyses demonstrated an increase in a flavin-like molecule under the 1018 EDL condition and sulfonates under the 1018 EAL condition. These data indicate the importance of S-cycling under the EAL condition, and that the EDL is associated with increased biocorrosion via indirect extracellular electron transfer mediated by endogenously produced flavin-like molecules.}, } @article {pmid31402466, year = {2019}, author = {Balasundararajan, V and Dananjeyan, B}, title = {Occurrence of diversified N-acyl homoserine lactone mediated biofilm-forming bacteria in rice rhizoplane.}, journal = {Journal of basic microbiology}, volume = {59}, number = {10}, pages = {1031-1039}, doi = {10.1002/jobm.201900202}, pmid = {31402466}, issn = {1521-4028}, support = {5-5/2014 - TS VII//Ministry of Human Resource Development, New Delhi, India/ ; }, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Bacteria/classification/*genetics/isolation & purification ; Biofilms/*growth & development ; Genetic Variation ; Oryza/growth & development/*microbiology ; Phylogeny ; Plant Roots/growth & development/microbiology ; Quorum Sensing ; RNA, Ribosomal, 16S/genetics ; Rhizosphere ; }, abstract = {Quorum sensing (QS)-mediated biofilm-forming rhizobacteria are indispensable due to their competitiveness in the crop rhizosphere. In the present work, we have reported on the occurrence of diversified bacterial species capable of producing N-acyl homoserine lactone (AHL) as the QS signal in the roots of a rice plant grown under field conditions. The AHL-producing bacteria were directly isolated from the rice root by the biosensor reporter (Chromobacterium violaceum CV026) overlay method and characterized for biofilm production by the microtiter plate method. A total of 48 QS-positive bacterial isolates were purified from different aged (7, 20, 24, 26, and 36 days) rice seedlings. The in vitro biofilm production and genetic diversity as revealed by BOX-PCR fingerprinting showed high variability among the isolates. Most of the best biofilm-forming isolates produced a N-butyryl dl-homoserine lactone (a C4-AHL type) signal in the medium. The 16S ribosomal RNA (rRNA) gene sequence of these putative elite isolates identified that they were close to Aeromonas hydrophila (QS7-4; QS36-2), A. enteropelongenes (QS20-8), A. veronii (QS36-3), Enterobacter sp. (QS20-11), Klebsiella pneumoniae (QS24-6), Kosakonia cowanii (QS24-21), Providentia rettigeri (QS24-2), Sphingomonas aquatilis (QS24-17), and Pseudomonas sihuiensis (QS24-20). These strains profusely colonized the rice root upon inoculation and formed biofilms on the surface of the root under gnotobiotic conditions. Developing inoculants from these strains would ensure competitive colonization on the rhizoplane of the crop through their biofilm and thereby improve plant growth and health.}, } @article {pmid31401655, year = {2019}, author = {Bajoul Kakahi, F and Ly, S and Tarayre, C and Deschaume, O and Bartic, C and Wagner, P and Compère, P and Derdelinckx, G and Blecker, C and Delvigne, F}, title = {Modulation of fungal biofilm physiology and secondary product formation based on physico-chemical surface properties.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {12}, pages = {1935-1946}, doi = {10.1007/s00449-019-02187-6}, pmid = {31401655}, issn = {1615-7605}, mesh = {*Biofilms ; Biomass ; Bioreactors ; Fermentation ; Fungal Proteins/chemistry ; Fungi/*physiology ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Polytetrafluoroethylene ; Surface Properties ; Trichoderma/*physiology ; }, abstract = {Relative to the amount of knowledge concerning bacterial biofilms, little is known about the impact of physico-chemical properties of support material on fungal biofilm adhesion and physiology. In the field of industrial fermentation, large-scale production of low-cost fungal secondary product is a challenging area of research. In the present work, the effect of physico-chemical surface properties of five different materials (Teflon, glass, Viton™ rubber, silicon rubber, and stainless steel) on the production of class II hydrophobins (HFBI and HFBII) from Trichoderma reesei (HFB2a-2) and Trichoderma harzianum) was evaluated. Two culture systems (shake flask and drip flow reactor (DFR)) were used in this study to promote biomass growth and the production of hydrophobins. Furthermore, the effect of physico-chemical surface properties (hydrophobicity, surface energy) and surface texture (roughness) of support material on the initial colonization and attachment of the fungal biofilm was evaluated. Maximum biofilm productivity was obtained using Viton™ rubber for T. reesei and Viton™ rubber and stainless steel as support materials for T. harzianum. Scanning electron microscope (SEM) revealed that fungal biofilm adhesion was higher on the rough hydrophobic Viton rubber surface as compared to the smooth hydrophobic Teflon surface. Initial colonization initiated because of surface irregularities and holes in the material as hyphal filaments. Moreover, compared to traditional submerged fermentation, a significant increase in biofilm productivity for both strains (T. reesei, T. harzianum) in all five materials was obtained.}, } @article {pmid31401462, year = {2019}, author = {Czuban, M and Wulsten, D and Wang, L and Di Luca, M and Trampuz, A}, title = {Release of different amphotericin B formulations from PMMA bone cements and their activity against Candida biofilm.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {183}, number = {}, pages = {110406}, doi = {10.1016/j.colsurfb.2019.110406}, pmid = {31401462}, issn = {1873-4367}, mesh = {Amphotericin B/*analogs & derivatives/chemistry/*pharmacology ; Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Bone Cements/analysis/chemistry ; Candida albicans/*drug effects/growth & development ; Candida glabrata/drug effects/growth & development ; Candida parapsilosis/drug effects/growth & development ; Compressive Strength ; Deoxycholic Acid/chemistry/*pharmacology ; Drug Combinations ; Drug Liberation ; Gentamicins/pharmacology ; Kinetics ; Materials Testing ; Microbial Sensitivity Tests ; Polymethyl Methacrylate/analysis/chemistry ; Porosity ; }, abstract = {Amphotericin B is used for local delivery from polymethylmethacrylate to treat fungal prosthetic joint infections. The optimal amphotericin B formulation and the influence of different poragens in the bone cements are unknown. To investigate the necessary amount of amphotericin B in the bone cement to prevent Candida biofilm several amphotericin B formulations were studied: non-liposomal and liposomal with or without poragen gentamicin. For the non-liposomal formulation, standard bile salt, the sodium deoxycholate, was used and additionally N-methyl-D-glucamine/palmitate was applied. The activity of the released amphotericin B was tested against C. albicans, C. glabrata, C. parapsilosis and C. krusei biofilms with application of the isothermal calorimeter and standard microbiological methods. Compressive strength was measured before and after antifungal elution from the cements. There is less aggregated N-methyl-D-glucamine/palmitate amphotericin B released but its antifungal activity is equivalent with the deoxycholate amphotericin B. The minimum quantity of antifungal preventing the Candida biofilm formation is 12.5 mg in gram of polymer powder for both non-liposomal formulations. The addition of gentamicin reduced the release of sodium deoxycholate amphotericin B. Gentamicin can be added to N-methyl-D-glucamine/palmitate amphotericin B in order to boost the antifungal release. When using liposomal amphotericin B more drug is released. All amphotericin B formulations were active against Candida biofilms. Although compressive strength slightly decreased, the obtained values were above the level of strength recommended for the implant fixation. The finding of this work might be beneficial for the treatment of the prosthetic joint infections caused by Candida spp.}, } @article {pmid31400984, year = {2019}, author = {Ionescu, A and Brambilla, E and Hahnel, S}, title = {Does recharging dental restorative materials with fluoride influence biofilm formation?.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {10}, pages = {1450-1463}, doi = {10.1016/j.dental.2019.07.019}, pmid = {31400984}, issn = {1879-0097}, mesh = {Biofilms ; *Cariostatic Agents ; Composite Resins ; Dental Materials ; *Fluorides ; Glass Ionomer Cements ; Humans ; Materials Testing ; }, abstract = {OBJECTIVES: To investigate the influence of recharging dental restorative materials with fluoride on biofilm formation.

METHODS: Specimens produced from a high-viscosity glass ionomer cement (HVGIC), a resin-modified glass ionomer cement (RMGIC), and a resin-based composite (RBC) were randomly allotted to incubation in artificial saliva either for one week (AS-1), for five weeks (AS-5), for five weeks including twice/day brushing with 1450ppm NaF toothpaste (AS-5-brush), or one-time exposition to 5000ppm NaF after five weeks of incubation (AS-5-exp). Human enamel was used as reference. Surface roughness and the release of fluoride from the specimens was determined; biofilm formation was simulated using mono- or multispecies microbiological models and analysed employing an MTT-based approach and confocal laser-scanning microscopy.

RESULTS: Monospecies biofilm formation was significantly reduced on HVGIC in comparison to RMGIC and RBC. It was also reduced on HVGIC and enamel after treatment with fluoride in groups AS-5-brush and AS-5-exp in comparison to AS-5. These effects were particularly pronounced after 24h, and less pronounced after 48h of biofilm formation. In the multispecies microbiological model, similar observations were identified for HVGIC, while for enamel a significant reduction in biofilm formation was observed in groups AS-5-brush and AS-5-exp. No significant effect of fluoride treatments was identified for RMGIC and RBC, regardless of the microbiological model applied.

SIGNIFICANCE: These data indicate that biofilm formation on the surfaces of a glass ionomer cement and enamel can be relevantly influenced by treatment with fluoride. Enamel may serve as a fluoride reservoir which requires regular recharge.}, } @article {pmid31400892, year = {2019}, author = {Vasileiou, NGC and Chatzopoulos, DC and Cripps, PJ and Ioannidi, KS and Gougoulis, DA and Chouzouris, TM and Lianou, DT and Gonzalez-Valerio, TC and Vallverdu, RG and Argyros, S and Cesio, M and Font, I and Mavrogianni, VS and Petinaki, E and Fthenakis, GC}, title = {Evaluation of efficacy of a biofilm-embedded bacteria-based vaccine against staphylococcal mastitis in sheep-A randomized, placebo-controlled field study.}, journal = {Journal of dairy science}, volume = {102}, number = {10}, pages = {9328-9344}, doi = {10.3168/jds.2019-16287}, pmid = {31400892}, issn = {1525-3198}, mesh = {Animals ; Bacterial Vaccines/*administration & dosage ; *Biofilms ; Female ; Incidence ; Lactation ; Mammary Glands, Animal/microbiology ; Mastitis/prevention & control/*veterinary ; Milk/microbiology ; Random Allocation ; Sheep ; Sheep Diseases/microbiology/*prevention & control ; Staphylococcal Infections/prevention & control/*veterinary ; }, abstract = {Our objective was to evaluate the efficacy of a vaccine against staphylococcal mastitis in 5 dairy sheep farms, with 316 ewes in the vaccinated (V) group and 307 in the control (C) group studied throughout a lactation period. Two administrations of the vaccine were performed during the last stage of gestation of ewes. Starting 15 d after lambing and at monthly intervals thereafter, up to 9 milk samplings were performed for bacteriological and cytological examinations. Staphylococcal isolates recovered were examined for biofilm formation. Blood samples were collected for measurement of IgG poly-N-acetylglucosamine-specific antibodies. The most frequently isolated bacteria were staphylococci: 56.4 and 76.1%, respectively, of total isolates recovered from ewes of group V and C, respectively; staphylococci as causal agents of mastitis were isolated less frequently from V (5.3%) than in ewes in C (10.3%). Among mastitis-associated staphylococcal isolates recovered from V ewes, a smaller proportion was biofilm-forming than among ones from C: 53.2% versus 74.9% of isolates; biofilm-forming staphylococci as causal agents of mastitis were isolated less frequently from ewes in group V (2.3%) than in ewes in group C (6.0%). Anti-poly-N-acetylglucosamine-specific antibody values increased in V ewes and were higher than in C; a greater proportion of ewes with low antibody titers developed staphylococcal mastitis (41.4%) than of V ewes with high antibody titers (17.0%). Incidence risk of mastitis, staphylococcal mastitis, and biofilm-associated staphylococcal mastitis was smaller in V than in C: 36.7, 17.1, and 8.0% versus 44.3, 30.9, and 18.9%, respectively. The first case of staphylococcal mastitis occurred later in V than in C: third versus second sampling point. Overall, efficacy of the vaccine was 44.6% for staphylococcal mastitis, 57.7% for biofilm-associated staphylococcal mastitis, 33.1% for staphylococcal intramammary infection, and 51.5% for biofilm-associated staphylococcal intramammary infection. Nevertheless, vaccination should not be the only means for controlling mastitis; other udder health management measures should be included therein to improve control of the infection.}, } @article {pmid31400863, year = {2019}, author = {Hans, S and Fatima, Z and Hameed, S}, title = {Retrograde signaling disruption influences ABC superfamily transporter, ergosterol and chitin levels along with biofilm formation in Candida albicans.}, journal = {Journal de mycologie medicale}, volume = {29}, number = {3}, pages = {210-218}, doi = {10.1016/j.mycmed.2019.07.003}, pmid = {31400863}, issn = {1773-0449}, mesh = {Animals ; Biofilms/*growth & development ; Biological Transport ; Caenorhabditis elegans/microbiology ; Candida albicans/genetics/*metabolism/pathogenicity ; Candidiasis/microbiology ; Chitin/*analysis ; Disease Models, Animal ; Ergosterol/*analysis ; Membrane Transport Proteins/*genetics/metabolism ; *Signal Transduction ; Virulence ; }, abstract = {OBJECTIVE: The rise in fungal infections is alarming due to emergence of multidrug drug resistance (MDR). Hence elucidating novel drug targets to circumvent the problem of MDR warrants immediate attention. This study analyzes the effect of retrograde (RTG) signaling disruption on major MDR mechanisms and virulence of the human pathogenic fungal species Candida albicans.

MATERIAL AND METHODS: Drug transporter activity was measured by rhodamine 6G (R6G) efflux. Membrane damage was studied by propidium iodide intake and ergosterol level determination. Cell wall effect was estimated by quantifying chitin levels and cell sedimentation rate. Biofilm formation was visualized by calcoflour white and crystal violet staining and measured by dry mass and MTT assay. Cell adherence to buccal epithelial cell was determined by trypan blue staining and MTT assay. Virulence was studied using nematode model Caenorhabditis elegans.

RESULT: We demonstrated that mutant of transcription factor CaRTG3 leads to impaired efflux activity of ATP Binding Cassette (ABC) superfamily multidrug transporters. We further uncover that rtg3 mutant exhibited a disrupted membrane, decreased ergosterol levels and increased chitin content. Furthermore, RTG signaling disruption leads to inhibited biofilm formation and cell adherence to buccal epithelial cells. Lastly, rtg3 mutant displayed a reduced infectivity in C. elegans illustrating its vulnerability as antifungal target. Interestingly, all the abrogated phenotypes could be rescued in the revertant strain of rtg3 mutant.

CONCLUSION: Present study establishes a link between RTG signaling, drug efflux and biofilm formation and validates CaRTG3 as antifungal target. Intricate studies are needed to further understand and exploit this therapeutic opportunity.}, } @article {pmid31400688, year = {2019}, author = {Li, H and Zhou, L and Lin, H and Zhang, W and Xia, S}, title = {Nitrate effects on perchlorate reduction in a H2/CO2-based biofilm.}, journal = {The Science of the total environment}, volume = {694}, number = {}, pages = {133564}, doi = {10.1016/j.scitotenv.2019.07.370}, pmid = {31400688}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors/microbiology ; Carbon Dioxide ; Denitrification ; Nitrates/*metabolism ; Nitrogen Oxides ; Oxidation-Reduction ; Perchlorates/analysis/*metabolism ; Water Pollutants, Chemical/analysis/*metabolism ; Water Purification/*methods ; }, abstract = {The H2/CO2-based membrane biofilm reactor (H2/CO2-MBfR) that effectively combines microporous diffusions of H2 and CO2 is efficient in removing perchlorate (ClO4[-]). Nitrate (NO3[-]) is a common oxidized contaminant frequently coexists with ClO4[-] in water, with the NO3[-] concentration in most ClO4[-]-contaminated waters being several orders of magnitude higher than ClO4[-]. Determining the effect of NO3[-] on ClO4[-] reduction is a critical issue in practice. The ClO4[-] reduction performance, biofilm microbial community and influencing mechanism were investigated under a series of feed NO3[-] loadings in this work. ClO4[-] reduction was slightly promoted when NO3[-]-N levels were <10 mg/L and inhibited at higher NO3[-]-N levels. Denitrification competed more strongly for H2 than ClO4[-] reduction, regardless of H2 availability. A higher NO3[-]-N loading was a strong driving force to change the biofilm microbial community. Betaproteobacteria were the dominant bacteria at all stages, and the biofilm reactor was enriched in Methyloversatilis and Zoogloea (31.9-56.5% and 10.6-25.8%, respectively). Changes in the relative amounts of Methyloversatilis and Zoogloea coincided with changes in the ClO4[-] fluxes and removal efficiencies and the relative abundances of nitrogen cycle functional genes. These results suggest that Methyloversatilis and Zoogloea likely follow independent reduction mechanisms for ClO4[-] removal.}, } @article {pmid31398534, year = {2019}, author = {Dieser, SA and Fessia, AS and Zanotti, AR and Raspanti, CG and Odierno, LM}, title = {Fibronectin and laminin induce biofilm formation by Streptococcus uberis and decrease its penicillin susceptibility.}, journal = {Microbial pathogenesis}, volume = {136}, number = {}, pages = {103652}, doi = {10.1016/j.micpath.2019.103652}, pmid = {31398534}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Culture Media/chemistry ; *Drug Tolerance ; Fibronectins/*metabolism ; Laminin/*metabolism ; Microbial Sensitivity Tests ; Penicillins/*pharmacology ; Streptococcus/*drug effects/growth & development ; }, abstract = {The aim of this study was to determine the effect of fibronectin and laminin on the in vitro biofilm formation by Streptococcus uberis and the susceptibility to penicillin under planktonic and biofilm growth conditions. We observed that a high percentage (76.5%) of the S. uberis isolates was weak biofilm producers in Todd Hewitt Broth (THB). A high percentage of moderate (38.2%) or strong (53%) biofilm producers was observed in THB supplemented with laminin or fibronectin, respectively. All S. uberis isolates growing as planktonic cells were sensitive to penicillin. Minimum biofilm inhibitory concentrations (MBICs) were ranging between 0.25 and 2 μg/ml, whereas minimum biofilm eradication concentrations (MBECs) ranging from 8 to 256 μg/ml. These results show that biofilm-growing S. uberis cells required higher concentrations of the antibiotic than those needed to inhibit planktonic cells. Similar MBICs of penicillin were obtained when S. uberis cells growing in THB supplemented or not with laminin or fibronectin, whereas the MBECs markedly increased when one of two proteins were added to culture medium compared with the medium without proteins. To the best of our knowledge, this is the first report of decreased susceptibility to penicillin likely related to a higher production of biofilms stimulated by laminin or fibronectin. Therapeutic failures of penicillin to treat S. uberis infections may be due to biofilm formation.}, } @article {pmid31398514, year = {2019}, author = {Shin, NR and Yi, YJ and Choi, JS}, title = {Hand motor functions on the presence of red fluorescent dental biofilm in older community-dwelling Koreans.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {28}, number = {}, pages = {120-124}, doi = {10.1016/j.pdpdt.2019.08.010}, pmid = {31398514}, issn = {1873-1597}, mesh = {Aged ; Biofilms/*growth & development ; Cross-Sectional Studies ; Female ; Fluorescence ; Hand/*physiopathology ; Humans ; Independent Living ; Male ; *Oral Hygiene ; Republic of Korea ; }, abstract = {BACKGROUND: The Quantitative Light-induced Fluorescence-Digital (QLF-D) system visualizes old and mature dental biofilm as red fluorescence. Risk factors for poor oral hygiene have been identified, however, few studies have evaluated the relationship between mature dental biofilm and hand motor functions. This study aimed to investigate the effects of two important manual motor functions for object manipulation -handgrip strength and manual dexterity- on the presence of red fluorescent dental biofilm in older community-dwelling Koreans using QLF-D, an optical device that reveals dental biofilm.

METHODS: This cross-sectional study included 70 Korean participants aged ≥65 years, all of whom completed questionnaires and were tested for handgrip strength and manual dexterity. In total, 840 dental surfaces were photographed using QLF-D, and ΔR20 values, which reflect mature dental biofilm accumulation, were calculated. The t-test was performed to analyze the differences in the ∆R20 values according to sociodemographic characteristics, health-related characteristics and hand motor functions, while multiple linear regression analysis was used to investigate the effects of hand motor functions on the ∆R20 values.

RESULTS: Multivariate regression analysis revealed that handgrip strength (β = -0.294) was the factor most strongly affecting mature dental biofilm accumulation (ΔR20), followed by tooth-brushing time (β = -0.262) and manual dexterity (β = -0.241).

CONCLUSIONS: Reductions in handgrip strength and manual dexterity were independent risk factors for pathogenic dental biofilm accumulation. The results of this investigation suggest that programs designed to prevent the decline, as well as improve, handgrip strength and manual dexterity might improve the oral hygiene of older adults.}, } @article {pmid31398473, year = {2019}, author = {Arenas-Vivo, A and Amariei, G and Aguado, S and Rosal, R and Horcajada, P}, title = {An Ag-loaded photoactive nano-metal organic framework as a promising biofilm treatment.}, journal = {Acta biomaterialia}, volume = {97}, number = {}, pages = {490-500}, doi = {10.1016/j.actbio.2019.08.011}, pmid = {31398473}, issn = {1878-7568}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*growth & development ; Delayed-Action Preparations/chemistry/pharmacology ; Metal Nanoparticles/*chemistry ; *Silver/chemistry/pharmacology ; Staphylococcus aureus/*physiology ; *Ultraviolet Rays ; }, abstract = {Surface biofilm inhibition is still currently a considerable challenge. Among other organisms, Staphylococcus aureus is notable for its ability to form a strong biofilm with proved resistance to chemotherapy. Contamination of high-touch surfaces with S. aureus biofilm not only promotes disease spread but also generates tremendous health-associated costs. Therefore, development of new bactericidal and antiadhesive surface coatings is a priority. Considering that metal-organic frameworks (MOFs) have recently emerged as promising antibacterial agents, we originally report here the synthesis of a multi-active silver-containing nanoscaled MOF composite as a potential surface coating against S. aureus biofilm owing to a triple effect: intrinsic bactericide activity of the MOF, biocidal character of silver nanoparticles (AgNPs), and photoactivity after UVA irradiation. AgNPs were successfully entrapped within the benchmarked nanoscaled porous photoactive titanium(IV) aminoterephthalate MIL-125(Ti)NH2 using a simple and efficient impregnation-reduction method. After complete characterization of the composite thin film, its antibacterial and anti-adherent properties were fully evaluated. After UVA irradiation, the composite coating exhibited relevant bacterial inhibition and detachment, improved ligand-to-cluster charge transfer, and steady controlled delivery of Ag[+]. These promising results establish the potential of this composite as an active coating for biofilm treatment on high-touch surfaces (e.g., surgical devices, door knobs, and rail bars). STATEMENT OF SIGNIFICANCE: Surface contamination due to bacterial biofilm formation is still a demanding issue, as it causes severe disease spread. One possible solution is the development of antifouling and antibacterial surface coatings. In this work, we originally propose the use of photoactive metal-organic frameworks (MOFs) for biofilm treatment. The novelty of this work relies on the following: i) the treatment of strongly contaminated surfaces, as previous studies with MOFs have exclusively addressed biofilm prevention; ii) this pioneering work reports both antiadherent effect, which removes the biofilm, and bacterial inhibition; iii) our original successful strategy has never been proposed thus far, involving the multi-active combination of 1) intrinsic antibacterial effect of a photoactive titanium-based nanoMOF, 2) immobilization of biocide silver nanoparticles, and 3) improved anti-bioadherent effect upon irradiation of the composite coating.}, } @article {pmid31398188, year = {2019}, author = {Rai, LS and Singha, R and Sanchez, H and Chakraborty, T and Chand, B and Bachellier-Bassi, S and Chowdhury, S and d'Enfert, C and Andes, DR and Sanyal, K}, title = {The Candida albicans biofilm gene circuit modulated at the chromatin level by a recent molecular histone innovation.}, journal = {PLoS biology}, volume = {17}, number = {8}, pages = {e3000422}, pmid = {31398188}, issn = {1545-7885}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*genetics ; Candidiasis/microbiology ; Chromatin/genetics/metabolism ; Fungal Proteins/metabolism ; Gene Expression/genetics ; Gene Expression Regulation, Fungal/genetics ; Gene Regulatory Networks/genetics ; Histones/genetics/*metabolism ; Humans ; Transcription Factors/metabolism ; }, abstract = {Histone H3 and its variants regulate gene expression but the latter are absent in most ascomycetous fungi. Here, we report the identification of a variant histone H3, which we have designated H3VCTG because of its exclusive presence in the CTG clade of ascomycetes, including Candida albicans, a human pathogen. C. albicans grows both as single yeast cells and hyphal filaments in the planktonic mode of growth. It also forms a three-dimensional biofilm structure in the host as well as on human catheter materials under suitable conditions. H3VCTG null (hht1/hht1) cells of C. albicans are viable but produce more robust biofilms than wild-type cells in both in vitro and in vivo conditions. Indeed, a comparative transcriptome analysis of planktonic and biofilm cells reveals that the biofilm circuitry is significantly altered in H3VCTG null cells. H3VCTG binds more efficiently to the promoters of many biofilm-related genes in the planktonic cells than during biofilm growth, whereas the binding of the core canonical histone H3 on the corresponding promoters largely remains unchanged. Furthermore, biofilm defects associated with master regulators, namely, biofilm and cell wall regulator 1 (Bcr1), transposon enhancement control 1 (Tec1), and non-dityrosine 80 (Ndt80), are significantly rescued in cells lacking H3VCTG. The occupancy of the transcription factor Bcr1 at its cognate promoter binding sites was found to be enhanced in the absence of H3VCTG in the planktonic form of growth resulting in enhanced transcription of biofilm-specific genes. Further, we demonstrate that co-occurrence of valine and serine at the 31st and 32nd positions in H3VCTG, respectively, is essential for its function. Taken together, we show that even in a unicellular organism, differential gene expression patterns are modulated by the relative occupancy of the specific histone H3 type at the chromatin level.}, } @article {pmid31397415, year = {2019}, author = {Sampaio, GG and Leódido, G and Gonçalves, LM and Paschoal, MA}, title = {In vitro antimicrobial potential of infant mouthwashes against streptococcus mutans biofilm: A preliminary study.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {30}, number = {3}, pages = {399-402}, doi = {10.4103/ijdr.IJDR_500_17}, pmid = {31397415}, issn = {1998-3603}, mesh = {Adolescent ; *Anti-Infective Agents ; *Anti-Infective Agents, Local ; Biofilms ; Child ; Humans ; Mouthwashes ; Streptococcus mutans ; }, abstract = {BACKGROUND: Children and teenagers accumulate dental plaque easily due to immature motor coordination present at this specific age. Thus, chemical solutions such as mouthwashes are used for biofilm control. The widespread use of mouthwash could potentially change the oral environment though there is no evidence of its effects on the biofilm.

AIM: The present study aimed to investigate the in vitro antimicrobial potential of infant mouthwashes on mature Streptococcus mutans biofilm.

METHODS: The susceptibility of S. mutans biofilm UA 159 (ATCC700610) to infant mouthwashes was tested with childrens mouthwashes containing the following active agents: G1-cetylpyridinium chloride, G2-xylitol and triclosan and G3-Malva sylvestris and xylitol. Phosphage-buffered saline (PBS) was used at the negative control (G4). In this study, cariogenic biofilm was exposed once a day for one minute to the mouthwashes over a period of five days. Following this, an aliquot of each mouthwash used was seeded in brain heart infusion (BHI) agar and then incubated at 37°C, 5% CO2 for 48 h. The results were expressed as colony-forming units (CFU) and converted into log10. The results were submitted to ANOVA and Tukey's test at 5%.

RESULTS: It was observed 7.75, 7.66, and 7.49 CFUlog10 values to G1, G2, and G3, respectively, with 9.53 CFUlog10 value to G4. Accordingly, all studied mouthwashes showed no significant statistical difference between them but with statistically significant bacterial reduction in comparison to control group.

CONCLUSION: Infant mouthwashes presented a highly significant antimicrobial effect on cariogenic biofilm in an in vitro model, which raises concern when used by a young population.}, } @article {pmid31397177, year = {2021}, author = {Acquaviva, R and D'Angeli, F and Malfa, GA and Ronsisvalle, S and Garozzo, A and Stivala, A and Ragusa, S and Nicolosi, D and Salmeri, M and Genovese, C}, title = {Antibacterial and anti-biofilm activities of walnut pellicle extract (Juglans regia L.) against coagulase-negative staphylococci.}, journal = {Natural product research}, volume = {35}, number = {12}, pages = {2076-2081}, doi = {10.1080/14786419.2019.1650352}, pmid = {31397177}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry/*pharmacology ; Biofilms/drug effects ; Chromatography, Liquid ; Coagulase/analysis ; Dose-Response Relationship, Drug ; Flavonoids/analysis ; Juglans/*chemistry ; Nuts/chemistry ; Phenols/analysis ; Plant Extracts/administration & dosage/analysis/chemistry/*pharmacology ; Plants, Medicinal/chemistry ; Staphylococcus/*drug effects/physiology ; Tandem Mass Spectrometry ; }, abstract = {Juglans regia L. (common walnut) is a deciduous tree belonging to Juglandaceae family. Since ancient time, walnut was widely used in traditional medicine for its antioxidant, antidiabetic, antimicrobial, anti-inflammatory, anti-atherogenic and liver-protective effects. In this work, the antibacterial and anti-biofilm activities of walnuts pellicle extract against coagulase-negative staphylococci were evaluated. Qualitative chemical analysis was performed by the thin layer chromatography. UPLC-Ms/Ms was used to identify the chemical composition of J. regia extract. The total flavonoid and phenolic contents were determined by the Aluminium chloride and Folin-Ciocalteu methods, respectively. The extract showed antibacterial activity with MIC ranging from 3.60 to 461.75 µg/ml and MBC ranging from 461.75 to >461.75 µg/ml. Furthermore, it significantly reduced biofilm biomass and cell viability in a dose-dependent manner. Biological activities of J. regia extract may be due to its high flavonoid and phenolic contents. The obtained results are promising and they deserve further scientific investigations.}, } @article {pmid31396394, year = {2019}, author = {Cameron, LC and Bonis, B and Phan, CQ and Kent, LA and Lee, AK and Hunter, RC}, title = {A putative enoyl-CoA hydratase contributes to biofilm formation and the antibiotic tolerance of Achromobacter xylosoxidans.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {20}, pmid = {31396394}, issn = {2055-5008}, mesh = {Achromobacter denitrificans/*drug effects/*enzymology/genetics/growth & development ; Anti-Bacterial Agents/*metabolism ; Biofilms/*drug effects/growth & development ; DNA Transposable Elements ; *Drug Tolerance ; Enoyl-CoA Hydratase/genetics/*metabolism ; Gene Deletion ; Mutagenesis, Insertional/*methods ; }, abstract = {Achromobacter xylosoxidans has attracted increasing attention as an emerging pathogen in patients with cystic fibrosis. Intrinsic resistance to several classes of antimicrobials and the ability to form robust biofilms in vivo contribute to the clinical manifestations of persistent A. xylosoxidans infection. Still, much of A. xylosoxidans biofilm formation remains uncharacterized due to the scarcity of existing genetic tools. Here we demonstrate a promising genetic system for use in A. xylosoxidans; generating a transposon mutant library which was then used to identify genes involved in biofilm development in vitro. We further described the effects of one of the genes found in the mutagenesis screen, encoding a putative enoyl-CoA hydratase, on biofilm structure and tolerance to antimicrobials. Through additional analysis, we find that a fatty acid signaling compound is essential to A. xylosoxidans biofilm ultrastructure and maintenance. This work describes methods for the genetic manipulation of A. xylosoxidans and demonstrated their use to improve our understanding of A. xylosoxidans pathophysiology.}, } @article {pmid31396193, year = {2019}, author = {Woodburn, KW and Jaynes, JM and Clemens, LE}, title = {Evaluation of the Antimicrobial Peptide, RP557, for the Broad-Spectrum Treatment of Wound Pathogens and Biofilm.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1688}, pmid = {31396193}, issn = {1664-302X}, abstract = {The relentless growth of multidrug resistance and generation of recalcitrant biofilm are major obstacles in treating wounds, particularly in austere military environments where broad-spectrum pathogen coverage is needed. Designed antimicrobial peptides (dAMPs) are constructed analogs of naturally occurring AMPs that provide the first line of defense in many organisms. RP557 is a dAMP resulting from iterative rational chemical structural analoging with endogenous AMPs, human cathelicidin LL-37 and Tachyplesin 1 and the synthetic D2A21 used as structural benchmarks. RP557 possesses broad spectrum activity against Gram-positive and Gram-negative bacteria and fungi, including recalcitrant biofilm with substantial selective killing over bacterial cells compared to mammalian cells. RP557 did not induce resistance following chronic passages of Pseudomonas aeruginosa and Staphylococcus aureus at subinhibitory concentrations, whereas concurrently run conventional antibiotics, gentamycin, and clindamycin, did. Furthermore, RP557 was able to subsequently eliminate the generated gentamycin resistant P. aeruginosa and clindamycin resistant S. aureus strains without requiring an increase in minimum inhibitory concentration (MIC) concentrations. RP557 was evaluated further in a MRSA murine wound abrasion infection model with a topical application of 0.2% RP557, completely eliminating infection. If these preclinical results are translated into the clinical setting, RP557 may become crucial for the empirical broad-spectrum treatment of wound pathogens, so that infections can be reduced to a preventable complication of combat-related injuries.}, } @article {pmid31396166, year = {2019}, author = {Yan, S and Wu, G}, title = {Can Biofilm Be Reversed Through Quorum Sensing in Pseudomonas aeruginosa?.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1582}, pmid = {31396166}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a Gram-negative bacterium causing diseases in plants, animals, and humans, and its drug resistance is a major concern in medical care. Biofilms play an important role in P. aeruginosa drug resistance. Three factors are most important to induce biofilm: quorum sensing (QS), bis-(3'-5')-cyclic diguanosine monophosphate (c-di-GMP), and small RNAs (sRNAs). P. aeruginosa has its own specific QS system (PQS) besides two common QS systems, LasI-LasR and RhlI-RhlR, in bacteria. PQS is interesting not only because there is a negative regulation from RhlR to pqsR but also because the null mutation in PQS leads to a reduced biofilm formation. Furthermore, P. aeruginosa dispersed cells have physiological features that are distinct between the planktonic cells and biofilm cells. In response to a low concentration of c-di-GMP, P. aeruginosa cells can disperse from the biofilms to become planktonic cells. These raise an interesting hypothesis of whether biofilm can be reversed through the QS mechanism in P. aeruginosa. Although a single factor is certainly not sufficient to prevent the biofilm formation, it necessarily explores such possibility. In this hypothesis, the literature is analyzed to determine the negative regulation pathways, and then the transcriptomic data are analyzed to determine whether this hypothesis is workable or not. Unexpectedly, the transcriptomic data reveal a negative regulation between lasI and psqR. Also, the individual cases from transcriptomic data demonstrate the negative regulations of PQS with laslI, laslR, rhlI, and rhlR under different experiments. Based on our analyses, possible strategies to reverse biofilm formation are proposed and their clinic implications are addressed.}, } @article {pmid31394187, year = {2019}, author = {Barrios-Gumiel, A and Sanchez-Nieves, J and Pérez-Serrano, J and Gómez, R and de la Mata, FJ}, title = {PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties.}, journal = {International journal of pharmaceutics}, volume = {569}, number = {}, pages = {118591}, doi = {10.1016/j.ijpharm.2019.118591}, pmid = {31394187}, issn = {1873-3476}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/drug effects ; Dendrimers/*administration & dosage ; Erythrocytes/drug effects ; Escherichia coli/drug effects/physiology ; Hemolysis/drug effects ; Metal Nanoparticles/*administration & dosage ; Microbial Sensitivity Tests ; Polyethylene Glycols/*administration & dosage ; Sheep ; Silanes/*administration & dosage ; Silver/*administration & dosage ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, [1]H NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.}, } @article {pmid31393795, year = {2019}, author = {Fronzo, C}, title = {An early, biofilm-focused wound management approach.}, journal = {Journal of wound care}, volume = {28}, number = {8}, pages = {524-526}, doi = {10.12968/jowc.2019.28.8.524}, pmid = {31393795}, issn = {0969-0700}, mesh = {*Bandages ; *Biofilms ; Humans ; Pressure Ulcer/*therapy ; *Wound Healing ; }, abstract = {Wound care experts at the 2019 EWMA conference described the need to adopt biofilm-based wound care, the case for silver dressings, the importance of early intervention and the benefits of effective antibiofilm technologies. Camila Fronzo, JWC chief sub editor, summarises the main points.}, } @article {pmid31392229, year = {2019}, author = {Abbaszadeh, A and Tehmasebi-Foolad, A and Rajabzadeh, A and Beigi-Brojeni, N and Zarei, L}, title = {Effects of Chitosan/Nano Selenium Biofilm on Infected Wound Healing in Rats; An Experimental Study.}, journal = {Bulletin of emergency and trauma}, volume = {7}, number = {3}, pages = {284-291}, pmid = {31392229}, issn = {2322-2522}, abstract = {OBJECTIVE: The present study was aimed at assessment of effect of application of Chitosan/Nano Selenium biofilm on infected wound healing in rats.

METHODS: Sixty-eight male Wistar rats were randomized into four groups of 17 animals each. In group I (Normal) the wounds were created with no infection. In group II (MRSA), the wounds were infected with methicillin resistant Staphylococcus aureus (MRSA). In group III (MRSA/CHIT), animals with infected wounds were dressed with chitosan biofilm only. In group IV (MRSA/CHIT/NS), animals with infected wounds were dressed with Chitosan/Nano Selenium biofilm.

RESULTS: There were significant differences in comparisons of group IV and other groups, particularly in terms of cellular infiltration and neovascularization. During the study period, scores for neovascularization was significantly higher in group IV rats than other groups (P<0.05). Polymorphonuclear (PMN) and mononuclear (MNC) cell count and fibroblast cell proliferation in group IV were significantly higher than those of other experimental groups (P<0.05).

CONCLUSION: Chitosan/Nano Selenium biofilm resulted in significant improvement in histopathological indices in full thickness infected wound healing.}, } @article {pmid31391891, year = {2019}, author = {Cox, KE and Melander, C}, title = {Anti-biofilm activity of quinazoline derivatives against Mycobacterium smegmatis.}, journal = {MedChemComm}, volume = {10}, number = {7}, pages = {1177-1179}, pmid = {31391891}, issn = {2040-2511}, support = {R01 AI106733/AI/NIAID NIH HHS/United States ; }, abstract = {Bacteria employ a number of mechanisms to resist the effects of antibiotics, including the formation of biofilms. We explored the anti-biofilm capabilities of a library of compounds based upon a 2-aminoquinazoline (2-AQ) scaffold against Mycobacterium smegmatis. This study resulted in the identification of 2-AQ derivatives with biofilm inhibition activity against M. smegmatis.}, } @article {pmid31390848, year = {2019}, author = {Pennone, V and Sanz-Gaitero, M and O'Connor, P and Coffey, A and Jordan, K and van Raaij, MJ and McAuliffe, O}, title = {Inhibition of L. monocytogenes Biofilm Formation by the Amidase Domain of the Phage vB_LmoS_293 Endolysin.}, journal = {Viruses}, volume = {11}, number = {8}, pages = {}, pmid = {31390848}, issn = {1999-4915}, mesh = {Amidohydrolases/genetics/*metabolism ; Bacteriophages/*enzymology ; *Biofilms ; Endopeptidases/chemistry/genetics/*metabolism ; Enzyme Activation ; *Host-Pathogen Interactions ; Hydrogen-Ion Concentration ; Listeria monocytogenes/classification/*physiology/*virology ; Recombinant Proteins ; Substrate Specificity ; Temperature ; }, abstract = {Listeria monocytogenes is a ubiquitous Gram-positive bacterium that is a major concern for food business operators because of its pathogenicity and ability to form biofilms in food production environments. Bacteriophages (phages) have been evaluated as biocontrol agents for L. monocytogenes in a number of studies and, indeed, certain phages have been approved for use as anti-listerial agents in food processing environments (ListShield and PhageGuard Listex). Endolysins are proteins produced by phages in the host cell. They cleave the peptidoglycan cell wall, thus allowing release of progeny phage into the environment. In this study, the amidase domain of the phage vB_LmoS_293 endolysin (293-amidase) was cloned and expressed in Escherichia. coli(E. coli). Muralytic activity at different concentrations, pH and temperature values, lytic spectrum and activity against biofilms was determined for the purified 293-amidase protein. The results showed activity on autoclaved cells at three different temperatures (20 °C, 37 °C and 50 °C), with a wider specificity (L. monocytogenes 473 and 3099, a serotype 4b and serogroup 1/2b-3b-7, respectively) compared to the phage itself, which targets only L. monocytogenes serotypes 4b and 4e. The protein also inhibits biofilm formation on abiotic surfaces. These results show the potential of using recombinant antimicrobial proteins against pathogens in the food production environment.}, } @article {pmid31389671, year = {2019}, author = {Martínez-García, S and Ortega-Peña, S and De Haro-Cruz, MJ and Aguilera-Arreola, MG and Alcántar-Curiel, MD and Betanzos-Cabrera, G and Jan-Roblero, J and Pérez-Tapia, SM and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {Non-biofilm-forming commensal Staphylococcus epidermidis isolates produce biofilm in the presence of trypsin.}, journal = {MicrobiologyOpen}, volume = {8}, number = {10}, pages = {e906}, pmid = {31389671}, issn = {2045-8827}, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects/*growth & development ; Eye Diseases/microbiology ; Gene Expression Profiling ; Genotype ; Healthy Volunteers ; Humans ; Osteoarthritis/microbiology ; Prosthesis-Related Infections/microbiology ; Skin/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*drug effects/genetics/*growth & development/isolation & purification ; Trypsin/*metabolism ; }, abstract = {Epidemiological studies comparing clinical and commensal Staphylococcus epidermidis isolates suggest that biofilm formation is a discriminant biomarker. A study showed that four non-biofilm-forming clinical S. epidermidis isolates could form an induced biofilm by trypsin treatment, suggesting that S. epidermidis can form biofilms in a protease-independent way and in a trypsin-induced way. In this study, the trypsin capacity to induce biofilm formation was evaluated in non-biofilm-forming S. epidermidis isolates (n = 133) in order to support this mechanism and to establish the importance of total biofilms (meaning the sum of protease-independent biofilm and trypsin-induced biofilm). Staphylococcus epidermidis isolates from ocular infections (OI; n = 24), prosthetic joint infections (PJI; n = 64), and healthy skin (HS-1; n = 100) were screened for protease-independent biofilm formation according to Christensen's method. The result was that there are significant differences (p < .0001) between clinical (43.2%) and commensal (17%) protease-independent biofilm producers. Meanwhile, non-biofilm-forming isolates were treated with trypsin, and biofilm formation was evaluated by the same method. The number of commensal trypsin-induced biofilm producers significantly increased from 17% to 79%. In contrast, clinical isolates increased from 43.2% to 72.7%. The comparison between clinical and commensal total biofilm yielded no significant differences (p = .392). A similar result was found when different isolation sources were compared (OI vs. HS-1 and PJI vs. HS-1). The genotype icaA[-] /aap[+] was associated with the trypsin-induced biofilm phenotype; however, no correlation was observed between aap mRNA expression and the level of trypsin-induced biofilm phenotype. Studying another group of commensal S. epidermidis non-biofilm-forming isolates (HS-2; n = 139) from different body sites, it was found that 70 isolates (60.3%) formed trypsin-induced biofilms. In conclusion, trypsin is capable of inducing biofilm production in non-biofilm-forming commensal S. epidermidis isolates with the icaA[-] /aap[+] genotype, and there is no significant difference in total biofilms when comparing clinical and commensal isolates, suggesting that total biofilms are not a discriminant biomarker.}, } @article {pmid31388951, year = {2019}, author = {Bó, LG and Almeida, RM and Cardoso, CMM and Zavarize, DG and Brum, SS and Mendonça, ARV}, title = {Acetylsalicylic acid biosorption onto fungal-bacterial biofilm supported on activated carbons: an investigation via batch and fixed-bed experiments.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {28}, pages = {28962-28976}, pmid = {31388951}, issn = {1614-7499}, mesh = {Adsorption ; Aspirin/*chemistry ; Bacteria/growth & development ; Biofilms/*growth & development ; Charcoal/*chemistry ; Hydrogen-Ion Concentration ; Kinetics ; Water Pollutants, Chemical ; }, abstract = {This study reports on acetylsalicylic acid (ASA) biosorption onto fungal-bacterial biofilm supported on two types of activated carbons (one commercial type made of coconut fibers, CAC, and one other manufactured from fruit rinds of Hymenaea stigonocarpa Mart., HYAC, which after biofilm inoculation, they were named CAC-b and HYAC-b), via batch and fixed-bed experiments. These materials were characterized by BET Specific Surface Area and Scanning Electronic Microscopy (SEM). Biosorption onto HYAC-b was 57.2% higher than HYAC. Despite presenting the highest biosorption capacity over time (qt = 85.4 ± 0.82 mg g[-1]), CAC-b had a lower increase in efficiency (32.4%) compared to CAC. Kinetic data from the biosorption experiments responded well to the pseudo-first-order model thus suggests the predominance of physisorption, while without biofilm presence, there was a better agreement with the pseudo-second-order model, suggesting chemisorption. The possible interaction mechanism of ASA to biofilm was attributed to ionic forces between the drug in anionic form and eventual presence of cationic by-products of the biologically active surface metabolism. Biosorption equilibrium data responded better to the Sips model and CAC-b presented the highest biosorption capacity (qe = 292.4 ± 2.01 mg g[-1]). A combination of faster volumetric flow rates, higher inlet concentrations and shorter beds accelerated the breakthrough time of ASA biosorption in the fixed-bed experiments. These operational conditions affected C/Co ratio in the following magnitude order: volumetric flow rate < inlet concentration < bed height. Breakthrough data responded better to the modified dose-response model compared to Thomas and Yoon-Nelson models.}, } @article {pmid31385644, year = {2019}, author = {Quan, K and Zhang, Z and Chen, H and Ren, X and Ren, Y and Peterson, BW and van der Mei, HC and Busscher, HJ}, title = {Artificial Channels in an Infectious Biofilm Created by Magnetic Nanoparticles Enhanced Bacterial Killing by Antibiotics.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {15}, number = {39}, pages = {e1902313}, doi = {10.1002/smll.201902313}, pmid = {31385644}, issn = {1613-6829}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Extracellular Polymeric Substance Matrix/metabolism ; Gentamicins/chemistry/pharmacology ; Magnetite Nanoparticles/*chemistry ; Staphylococcus aureus/drug effects/metabolism ; }, abstract = {The poor penetrability of many biofilms contributes to the recalcitrance of infectious biofilms to antimicrobial treatment. Here, a new application for the use of magnetic nanoparticles in nanomedicine to create artificial channels in infectious biofilms to enhance antimicrobial penetration and bacterial killing is proposed. Staphylococcus aureus biofilms are exposed to magnetic-iron-oxide nanoparticles (MIONPs), while magnetically forcing MIONP movement through the biofilm. Confocal laser scanning microscopy demonstrates artificial channel digging perpendicular to the substratum surface. Artificial channel digging significantly (4-6-fold) enhances biofilm penetration and bacterial killing efficacy by gentamicin in two S. aureus strains with and without the ability to produce extracellular polymeric substances. Herewith, this work provides a simple, new, and easy way to enhance the eradication of infectious biofilms using MIONPs combined with clinically applied antibiotic therapies.}, } @article {pmid31384892, year = {2019}, author = {He, ZY and Zhou, W and Huang, ZW and Liang, JP and Jiang, W}, title = {[The effect of Streptococcus mutans luxS gene on mixed-species biofilm communities].}, journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology}, volume = {28}, number = {2}, pages = {113-117}, pmid = {31384892}, issn = {1006-7248}, mesh = {*Bacterial Proteins/genetics/physiology ; *Biofilms ; *Carbon-Sulfur Lyases/genetics/physiology ; Lactobacillus acidophilus ; Real-Time Polymerase Chain Reaction ; *Streptococcus mutans/genetics ; }, abstract = {PURPOSE: To evaluate the effect of S.mutans luxS gene on mixed-species biofilms communities.

METHODS: Biofilms were formed by S. mutans (wild type strain, its luxS overexpression strain and luxS knockout strain) and Lactobacillus acidophilus (ATCC4356) with a ratio of 1:1 at 37℃ for 4 h, 14 h and 24 h. MTT assay was used to detect the quantification of the biofilms formed. The structures of biofilms were observed under confocal laser scanning microscopy after 24 h, and expression of biofilm-related genes (ftf, smu630, brpA, gbpB, gtfB, vicR, comDE and relA) was investigated by real-time PCR. Statistical analysis was performed with SPSS17.0 software package.

RESULTS: The results showed that biofilm formed by S. mutans(wild type strain, its luxS overexpression strain and luxS knockout strain) and L.acidophilus after 14 h were 0.481±0.024, 0.591±0.023 and 0.279±0.019, respectively. The same findings were present after 24 h, the biofilm formed by S.mutans overexpression strain with L.acidophilus was higher than wild type strain, and the biofilm formed by knockout strain significantly decreased; but there was no significant difference at 4 h time points. CLSM images revealed that both S.mutans overexpression strain and its wild type strain tended to aggregate into distinct clusters and dense structures, whereas the luxS knockout strain appeared relatively sparse. Compared with wild type strain, all of the genes examined were upregulated in the biofilms formed by the overexpression strain, and were downregulated in the biofilms formed by the luxS mutant strain in mixed-species biofilm.

CONCLUSIONS: S.mutans luxS gene can affect mixed-species biofilm formation with L.acidophilus, which provides evidences for further study.}, } @article {pmid31382580, year = {2019}, author = {Cattò, C and Cappitelli, F}, title = {Testing Anti-Biofilm Polymeric Surfaces: Where to Start?.}, journal = {International journal of molecular sciences}, volume = {20}, number = {15}, pages = {}, pmid = {31382580}, issn = {1422-0067}, mesh = {Bacteria/*drug effects/growth & development/pathogenicity ; Biofilms/*drug effects/growth & development ; Equipment and Supplies/*microbiology ; Humans ; Polymers/chemistry/*pharmacology ; Surface Properties ; }, abstract = {Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.}, } @article {pmid31382523, year = {2019}, author = {Karampoula, F and Doulgeraki, AI and Fotiadis, C and Tampakaki, A and Nychas, GE}, title = {Monitoring Biofilm Formation and Microbial Interactions that May Occur During a Salmonella Contamination Incident across the Network of a Water Bottling Plant.}, journal = {Microorganisms}, volume = {7}, number = {8}, pages = {}, pmid = {31382523}, issn = {2076-2607}, support = {380229//European Social Fund/ ; 548//Education and Lifelong Learning/ ; }, abstract = {The present study aims to monitor the ability of Salmonella to colonize and compete as a member of the mixed species biofilm within key points at a water bottling plant, in case of a contamination incident with this major foodborne pathogen. To achieve this goal, bacterial communities throughout the production line were collected and their identities were investigated by microbial counts and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). These bacterial communities alone or along with constructed Salmonella enterica serovar Typhimurium (ST) fluorescence-based bioreporters were left to form a biofilm on stainless steel for 6 days at 20 °C. ST bioreporters were constructed by introducing plasmids expressing EYFP (enhanced yellow fluorescent protein) fusions of the genes csgB, csrA, sspH2, and fliD into ST 14028S. The bead vortexing-plate counting method was applied for the enumeration of the biofilm population, while the behavior of the bioreporters was evaluated by fluorescence microscopy. From a set of 16 samples that were collected from the plant, species of Citrobacter, Staphylococcus, Pseudomonas, Bacillus, and Exiguobacterium were identified. The presence of these indigenous bacteria neither inhibited nor enhanced the biofilm formation of ST in mixed bacterial communities (p > 0.05). Furthermore, the csrA-based bioreporter was shown to be induced in multispecies biofilms with Citrobacter. In conclusion, this study enhanced our knowledge of bacterial interactions occurring within a biofilm in a water bottling plant.}, } @article {pmid31382160, year = {2019}, author = {Martins, ML and Monteiro, ASN and Guimarães, JEC and Guimarães, MBCT and da Silva, RF and Cabral, LM and Farah, A and dePaula, J and Romanos, MTV and Maia, LC and Cavalcanti, YW and Fonseca-Gonçalves, A}, title = {Cytotoxic and antibacterial effect of a red propolis mouthwash, with or without fluoride, on the growth of a cariogenic biofilm.}, journal = {Archives of oral biology}, volume = {107}, number = {}, pages = {104512}, doi = {10.1016/j.archoralbio.2019.104512}, pmid = {31382160}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Brazil ; Chlorhexidine ; Fluorides ; Mouthwashes/*pharmacology ; Propolis/*pharmacology ; Streptococcus/drug effects ; }, abstract = {OBJECTIVE: To evaluatein vitro the antibacterial activity, the antibiofilm effect and the cytotoxic potential of mouthwashes containing Brazilian red propolis with or without fluoride.

METHODS: The minimum inhibitory and bactericidal concentrations (MIC and MBC) against S. mutans, S. sanguinis, S. salivarius and L. casei were determined for RPE mouthwashes. A cariogenic biofilm with the aforementioned bacteria was formed over cellulose membrane disks (N = 30, 13 mm), which were submitted for 1 min to the following mouthwashes: plain mouthwash base; 0.05% NaF; 0.8% RPE; 0.8% RPE + 0.05% NaF and 0.12% chlorhexidine (CHX). The bacterial viability and the production of extracellular polysaccharide (EPS) were measured. Cytotoxic potential of the mouthwashes was also evaluated. For bacterial viability and EPS production, Mann-Withney and one-way ANOVA tests were performed followed by Tukey, with results considered significant when p ≤ 0.05.

RESULTS: MIC and MBC values of RPE mouthwashes ranged from 7.44 to 29.76 mg/mL and from 7.44 to ≥59.52 mg/mL, respectively, presenting better action against S. salivarius. RPE mouthwashes showed 44% of viable cells after 1 min of contact with fibroblasts. RPE (7.74) had the greatest reduction of viable total microorganisms and did not differ from the RPE + NaF (7.95) (p = 0.292). CHX (7.54) was the most effective in reducing Streptococcus spp, but did not differ from RPE (p = 0.521) and RPE + NaF (p = 0.238). There was no difference between the treatments regarding EPS production.

CONCLUSION: RPE and RPE + NaF mouthwash showed similar antibacterial activity, toxicity level and antibiofilm effect compared to CHX.}, } @article {pmid31380192, year = {2019}, author = {Lei, W and Bruchmann, J and Rüping, JL and Levkin, PA and Schwartz, T}, title = {Biofilm Bridges Forming Structural Networks on Patterned Lubricant-Infused Surfaces.}, journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)}, volume = {6}, number = {13}, pages = {1900519}, pmid = {31380192}, issn = {2198-3844}, abstract = {Despite many decades of research, biofilm architecture and spreading mechanisms are still not clear because of the heterogenous 3D structure within biofilms. Here, patterned "slippery" lubricant-infused porous surfaces are utilized to study biofilm structure of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Staphylococcus aureus. It is found that bacteria are able to spread over bacteria-repellent lubricant-infused regions by using a mechanism, termed "biofilm bridges". Here, it is demonstrated that bacteria use bridges to form interconnected networks between distant biofilm colonies. Detailed structure of bridges shows a spatial distribution of bacteria with an accumulation of respiratory active bacteria and biomass in the bridges. The core-shell structure of bridges formed by two-species mixed population is illustrated. It is demonstrated that eDNA and nutrients have a strong effect on biofilm bridges formation. Thus, it is believed that biofilm bridging is important to reveal the structure and communication within biofilms.}, } @article {pmid31379772, year = {2019}, author = {Josse, J and Valour, F and Maali, Y and Diot, A and Batailler, C and Ferry, T and Laurent, F}, title = {Interaction Between Staphylococcal Biofilm and Bone: How Does the Presence of Biofilm Promote Prosthesis Loosening?.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1602}, pmid = {31379772}, issn = {1664-302X}, abstract = {With the aging of population, the number of indications for total joint replacement is continuously increasing. However, prosthesis loosening can happen and is related to two major mechanisms: (1) aseptic loosening due to prosthesis micromotion and/or corrosion and release of wear particles from the different components of the implanted material and (2) septic loosening due to chronic prosthetic joint infection (PJI). The "aseptic" character of prosthesis loosening has been challenged over the years, especially considering that bacteria can persist in biofilms and be overlooked during diagnosis. Histological studies on periprosthetic tissue samples reported that macrophages are the principle cells associated with aseptic loosening due to wear debris. They produce cytokines and favor an inflammatory environment that induces formation and activation of osteoclasts, leading to bone resorption and periprosthetic osteolysis. In PJIs, the presence of infiltrates of polymorphonuclear neutrophils is a major criterion for histological diagnosis. Neutrophils are colocalized with osteoclasts and zones of osteolysis. A similar inflammatory environment also develops, leading to bone resorption through osteoclasts. Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus lugdunensis are the main staphylococci observed in PJIs. They share the common feature to form biofilm. For S. aureus and S. epidermidis, the interaction between biofilm and immunes cells (macrophages and polymorphonuclear neutrophils) differs regarding the species. Indeed, the composition of extracellular matrix of biofilm seems to impact the interaction with immune cells. Recent papers also reported the major role of myeloid-derived suppressor cells in biofilm-associated PJIs with S. aureus. These cells prevent lymphocyte infiltration and facilitate biofilm persistence. Moreover, the role of T lymphocytes is still unclear and potentially underestimates. In this review, after introducing the cellular mechanism of aseptic and septic loosening, we will focus on the interrelationships between staphylococcal biofilm, immune cells, and bone cells.}, } @article {pmid31378149, year = {2021}, author = {Wang, W and Nemati, M}, title = {Co-biodegradation of naphthenic acids in anoxic denitrifying biofilm reactors.}, journal = {Environmental technology}, volume = {42}, number = {7}, pages = {984-1000}, doi = {10.1080/09593330.2019.1650122}, pmid = {31378149}, issn = {1479-487X}, mesh = {Biodegradation, Environmental ; Biofilms ; Carboxylic Acids ; *Oil and Gas Fields ; *Water Pollutants, Chemical/analysis ; }, abstract = {Anoxic co-biodegradation of linear and cyclic naphthenic acids (NAs) namely octanoic acid, trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), cis- and trans-4-methyl-1-cyclohexane-acetic acids (cis-4MCHAA and trans-4MCHAA) was investigated in denitrifying biofilm reactors. In all evaluated compositions, co-biodegradation of NAs was coupled to denitrification, with octanoic acid showing the fastest biodegradation rate (1180.4 mg L[-1] h[-1] at loading rate of 1180.4 mg L[-1] h[-1]), followed by trans-4MCHCA (398.1 mg L[-1] h[-1] at loading rate of 435.8 mg L[-1] h[-1]), trans-4MCHAA (25.7 mg L[-1] h[-1] at loading rate of 221.7 mg L[-1] h[-1]), and cis-4MCHAA (5.3 mg L[-1] h[-1] at loading rate of 16.9 mg L[-1] h[-1]). Biodegradation of octanoic acid and trans-4MCHCA were not influenced by the presence of recalcitrant NAs (cis- and trans-4MCHAA). Co-biodegradation of cis- and trans-4MCHAA with octanoic acid, trans-4MCHCA, or their combination enhanced the biodegradability of these recalcitrant NAs, with the positive impact being more pronounced for trans-4MCHCA. Finally anoxic co-biodegradation of NAs under denitrifying conditions proceeded at rates that were faster than the aerobic rates obtained in similar mixtures. Anoxic biodegradation, therefore, is an effective alternative for in situ treatment of oil sands process water in anoxic stabilization ponds amended with nitrate, or as an ex situ treatment approach in denitrifying bioreactors whereby the cost and technical challenges of aeration are eliminated.}, } @article {pmid31376667, year = {2019}, author = {Li, X and Wang, X and Lee, DJ and Yan, WM}, title = {Highly heterogeneous interior structure of biofilm wastewater for enhanced pollutant removals.}, journal = {Bioresource technology}, volume = {291}, number = {}, pages = {121919}, doi = {10.1016/j.biortech.2019.121919}, pmid = {31376667}, issn = {1873-2976}, mesh = {Biofilms ; Biological Transport ; *Environmental Pollutants ; *Wastewater ; }, abstract = {Biofilm processes are widely used in wastewater treatment. The biofilm has highly heterogeneous interior structure, which can significantly affect the transport processes and the biological reactions over the biofilm. This study for the first time detailed the complicated velocity and concentration fields of substrate in a real biofilm structure. With a real biofilm interior being profiled and meshed to numerical solutions, the flow-through mode has significant distortion of inflow velocity fields and concentration distributions, which lead to enhanced biological reactions at regimes nearby major pores. Conversely, the crossflow mode depends weakly on the biofilm interior structure. The uniform biofilm model fails to describe the real biofilm processes. Future research needs based on real biofilm structures were discussed.}, } @article {pmid31376126, year = {2019}, author = {Kumari, S and Das, S}, title = {Expression of metallothionein encoding gene bmtA in biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 and understanding its involvement in Pb(II) resistance and bioremediation.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {28}, pages = {28763-28774}, pmid = {31376126}, issn = {1614-7499}, support = {BT/PR14998/GBD/27/279/2010//Department of Biotechnology , Ministry of Science and Technology/ ; }, mesh = {*Biodegradation, Environmental ; Biofilms ; Escherichia coli/metabolism ; Lead/*metabolism ; Metallothionein/*metabolism ; Metals, Heavy ; Plankton ; Polysaccharides, Bacterial ; Pseudomonas aeruginosa/metabolism/*physiology ; }, abstract = {The genetic basis and biochemical aspects of heavy metal endurance abilities have been precisely studied in planktonic bacteria; however, in nature, bacteria mostly grows as surface-attached communities called biofilms. A hallmark trait of biofilm is increased resistance to heavy metals compared with the resistance of planktonic bacteria. A proposed mechanism that contributes to this increased resistance is the enhanced expression of metal-resistant genes. bmtA gene coding for metallothionein protein is one such metal-resistant gene found in many bacterial spp. In the present study, lead (Pb) remediation potential of a biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 was explored. Biofilm-forming marine bacterium P. aeruginosa N6P6 possess bmtA gene and shows resistance towards many heavy metals, i.e., Pb, Cd, Hg, Cr, and Zn. The expression of metallothionein encoding gene bmtA is significantly high in 48-h-old biofilm culture (11. 4 fold) followed by 24-h-old biofilm culture of P. aeruginosa N6P6 (4.7 fold) (P < 0.05). However, in the case of planktonically grown culture of P. aeruginosa N6P6, the highest expression of bmtA gene was observed in 24-h-old culture. The expression of bmtA also increased significantly with increase in Pb concentration up to 800 ppm. CSLM analysis indicated significant reduction in the raw integrated density of biofilm-associated lipids and polysaccharides (PS) of P. aeruginosa N6P6 biofilm grown in Pb (sub-lethal concentration)-amended medium (P < 0.05), whereas no significant reduction was observed in the raw integrated density of EPS-associated protein. The role of bmtA gene as Pb(II)-resistant determinant was characterized by overexpressing the bmtA gene derived from P. aeruginosa N6P6 in Escherichia coli BL21(DE3). ESI-MS and SDS-PAGE analyses validated the presence of 11.5-kDa MT protein isolated from Pb(II)-induced recombinant E. coli BL21(DE3) harboring bmtA gene.}, } @article {pmid31375964, year = {2019}, author = {Fonseca, DL and Bassin, JP}, title = {Investigating the most appropriate methods for attached solids determination in moving-bed biofilm reactors.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {11}, pages = {1867-1878}, doi = {10.1007/s00449-019-02182-x}, pmid = {31375964}, issn = {1615-7605}, mesh = {Biofilms/*growth & development ; *Bioreactors ; *Models, Biological ; }, abstract = {Moving-bed biofilm reactors (MBBR) have been employed worldwide as an efficient technology for the treatment of a diverse set of wastewaters. Although the attached biomass represents the major fraction of solids in MBBR systems, there is still no standard for its reliable quantification. An extensive literature review indicated that several methods for attached biomass assessment are applied, hindering the comparability of results issued from different studies. Therefore, the most reported methods for biofilm quantification in the MBBR literature were compared using three different carriers. The results revealed that the performance of each method was biased depending on the carrier type and shape. Moreover, differences in total attached solids (TAS) concentrations varied from 13% up to more than 90%, depending on the employed method for a given carrier. Overall, direct weighing of the carrier containing the biofilm, accounting for the clean carrier weight, and manual extraction of the biofilm, preceded or not by sonication for at least 15 min, were the most suitable techniques for assessing TAS and the volatile/total solids ratio in non-porous medias, respectively. The results here presented may be used as a frame of reference for standardization of the methods for assessing the biofilm mass in MBBR carriers.}, } @article {pmid31374264, year = {2019}, author = {Sherly Carolyn, J and Selva Raj, D and Malaikozhundan, B and Govindarajan, M and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Al-Anbr, MN and Alobaidi, AS and Vaseeharan, B}, title = {Anti-cancer, anti-biofilm, and anti-inflammatory properties of hen's albumen: A photodynamic approach.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {28}, number = {}, pages = {1-7}, doi = {10.1016/j.pdpdt.2019.07.026}, pmid = {31374264}, issn = {1873-1597}, mesh = {Albumins/*pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Anti-Inflammatory Agents/*pharmacology ; Antineoplastic Agents/*pharmacology ; Biofilms/*drug effects ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Chickens ; Coleoptera ; Female ; Hep G2 Cells/drug effects ; Humans ; Microbial Sensitivity Tests ; Photochemotherapy/*methods ; }, abstract = {The albumen plays a major role in the protection of eggs against microorganisms. It contains an arsenal of natural antimicrobial molecules and antibacterial proteins, including the well-known ovotransferrin and lysozyme, which exert their activities against a range of bacteria. In the present study, the hen's albumen extract treated with the dried insect body of blister beetle M. pustulata was assessed for antibacterial, antibiofilm, anti-inflammatory and anti-proliferative activity. The zone of inhibition against Gram positive E. faecalis and S. aureus was 10.8 mm and 12.1 mm respectively at 100 μg mL[-1]. However, it was 13.6 mm and 15.3 mm for Gram negative P. aeruginosa and P. vulgaris respectively. The biofilm of tested bacteria was significantly inhibited at 100 μg mL[-1]. The hydrophobicity of bacterial biofilms was considerably condensed after treatment with the hen's albumen extracts at 100 μg mL[-1]. The anti-inflammatory activity of hen's albumen extracts was confirmed by the inhibition of cyclooxygenase (COX) enzyme to 84.91% at 100 μg mL[-1] with the relative IC50 of 8.26 μg mL[-1]. The albumen extract effectively inhibited the viability (23.61%) of HepG2 hepatic cancer cells at 100 μg mL[-1]. The anti-proliferative activity of the albumen extracts was further revealed by the induction of HepG2 apoptotic cell morphology. This study concludes that the hen's albumen extract treated with M. pustulata is a natural therapeutic agent to treat biofilm associated clinical bacteria, inflammations and human hepatic cancer cells.}, } @article {pmid31373891, year = {2019}, author = {Bottino, MA and Pereira, S and Amaral, M and Milhan, N and Pereira, CA and Camargo, S and Carvalho, A and Melo, RM}, title = {Streptococcus mutans Biofilm Formation and Cell Viability on Polymer-infiltrated Ceramic and Yttria-stabilized Polycrystalline Zirconium Dioxide Ceramic.}, journal = {Operative dentistry}, volume = {44}, number = {6}, pages = {E271-E278}, doi = {10.2341/18-278-L}, pmid = {31373891}, issn = {1559-2863}, mesh = {Biofilms ; Cell Survival ; Ceramics ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; *Polymers ; *Streptococcus mutans ; Surface Properties ; Yttrium ; Zirconium ; }, abstract = {OBJECTIVE: The aim of this study was to investigate the biofilm formation and cell viability of a polymer-infiltrated ceramic (PIC) and an yttria-stabilized polycrystalline zirconium dioxide ceramic (Y-TZP). The null hypothesis was that there would be no difference in biofilm formation and cell viability between the materials.

METHODS AND MATERIALS: Streptococcus mutans biofilm was analyzed with scanning electron microscopy (SEM), confocal laser scanning microscopy, and colony counting (colony-forming units/mL). The cell viability (fibroblasts) of both materials was measured with 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium) (MTT) test. Roughness measurements were also performed.

RESULTS: The PIC displayed higher roughness but showed similar colony-forming units and biovolume values to those of Y-TZP. SEM showed a higher amount of adhered fibroblasts on the PIC surface on the first day and similar amounts on both materials after seven days. Moreover, the materials were biocompatible with human fibroblasts.

CONCLUSION: PIC and Y-TZP are biocompatible and present the same characteristics for biofilm formation; therefore, they are indicated for indirect restorations and implant abutments.}, } @article {pmid31373035, year = {2019}, author = {Simkins, JW and Stewart, PS and Codd, SL and Seymour, JD}, title = {Non-invasive imaging of oxygen concentration in a complex in vitro biofilm infection model using [19] F MRI: Persistence of an oxygen sink despite prolonged antibiotic therapy.}, journal = {Magnetic resonance in medicine}, volume = {82}, number = {6}, pages = {2248-2256}, pmid = {31373035}, issn = {1522-2594}, support = {R01 GM109452/GM/NIGMS NIH HHS/United States ; }, mesh = {Alginates/chemistry ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Calibration ; Escherichia coli/metabolism ; *Fluorine-19 Magnetic Resonance Imaging ; Humans ; Oxygen/*chemistry ; *Signal Processing, Computer-Assisted ; Wound Healing ; Wound Infection/*microbiology ; }, abstract = {PURPOSE: Oxygen availability is a critical determinant of microbial biofilm activity and antibiotic susceptibility. However, measuring oxygen gradients in these systems remains difficult, with the standard microelectrode approach being both invasive and limited to single-point measurement. The goal of the study was to develop a [19] F MRI approach for 2D oxygen mapping in biofilm systems and to visualize oxygen consumption behavior in real time during antibiotic therapy.

METHODS: Oxygen-sensing beads were created by encapsulating an emulsion of oxygen-sensing fluorocarbon into alginate gel. Escherichia coli biofilms were grown in and on the alginate matrix, which was contained inside a packed bed column subjected to nutrient flow, mimicking the complex porous structure of human wound tissue, and subjected to antibiotic challenge.

RESULTS: The linear relationship between [19] F spin-lattice relaxation rate R1 and local oxygen concentration permitted noninvasive spatial mapping of oxygen distribution in real time over the course of biofilm growth and subsequent antibiotic challenge. This technique was used to visualize persistence of microbial oxygen respiration during continuous gentamicin administration, providing a time series of complete spatial maps detailing the continued bacterial utilization of oxygen during prolonged chemotherapy in an in vitro biofilm model with complex spatial structure.

CONCLUSIONS: Antibiotic exposure temporarily causes oxygen consumption to enter a pseudosteady state wherein oxygen distribution becomes fixed; oxygen sink expansion resumes quickly after antibiotic clearance. This technique may provide valuable information for future investigations of biofilms by permitting the study of complex geometries (typical of in vivo biofilms) and facilitating noninvasive oxygen measurement.}, } @article {pmid31372943, year = {2019}, author = {Ansari, FA and Ahmad, I}, title = {Isolation, functional characterization and efficacy of biofilm-forming rhizobacteria under abiotic stress conditions.}, journal = {Antonie van Leeuwenhoek}, volume = {112}, number = {12}, pages = {1827-1839}, doi = {10.1007/s10482-019-01306-3}, pmid = {31372943}, issn = {1572-9699}, mesh = {Bacillus/*physiology ; Biofilms/*growth & development ; Brevibacterium/*physiology ; Gammaproteobacteria/*physiology ; Plant Growth Regulators/*metabolism ; *Soil Microbiology ; *Stress, Physiological ; }, abstract = {Abiotic stresses such as salinity, drought and excessive heat are associated with significant loss of crop productivity globally, and require effective strategies for their reduction or tolerance. Biofilm-forming rhizobacteria, which harbor multifarious plant growth promoting traits and tolerance to abiotic stress, are believed to benefit plant health and production even under environmental stresses. The primary objective of this study was to investigate indigenous biofilm-forming rhizobacteria (Pseudomonas spp., Bacillus sp., Pantoea sp., Brevibacterium sp. and Acinetobacter sp.) for their functional diversity relevant to plant growth promoting activities, biofilm development and tolerance to abiotic stress conditions. The most promising isolates among FAP1, FAP2, FAP3, FAP4, FAP5, FAP10, FAB1, FAB3 and FAA1 were selected. Rhizobacteria exhibited high tolerance to salinity (1.5 M NaCl) and drought stress (up to 55% PEG-6000) conditions in vitro. The isolates demonstrated varying levels of PGP activities (IAA production and phosphate solubilization), biofilm development, and production of alginate and exopolysaccharides in the presence of salinity, drought stress and elevated temperature. Further efficacy of the isolates was demonstrated by inoculating to wheat (Triticum aestivum L.) plants in greenhouse conditions under both normal and drought stress for up to 30 days inoculation. The plant growth potential of the isolates was in the order of FAP3 > FAB3 > FAB1 > FAP10 > FAP5 > FAP4 > FAA1 > FAP2 > FAP1. The present study resulted in successful selection of promising PGPR as identified by 16S rRNA gene sequence analysis. Field study is needed to evaluate their relative performance in both 'normal' and stressed environments in order to be exploited for plant stress management.}, } @article {pmid31371744, year = {2019}, author = {Stępień-Pyśniak, D and Hauschild, T and Kosikowska, U and Dec, M and Urban-Chmiel, R}, title = {Biofilm formation capacity and presence of virulence factors among commensal Enterococcus spp. from wild birds.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {11204}, pmid = {31371744}, issn = {2045-2322}, mesh = {Animals ; Bacterial Proteins/genetics/isolation & purification ; Biofilms ; Birds/*microbiology ; Cloaca/microbiology ; Enterococcus/genetics/isolation & purification/*pathogenicity ; Feces/microbiology ; *Gastrointestinal Microbiome ; Gram-Positive Bacterial Infections/*microbiology/prevention & control ; Humans ; Microbial Sensitivity Tests ; Operon/genetics ; Opportunistic Infections/*microbiology/prevention & control ; Symbiosis ; Virulence/genetics ; Virulence Factors/genetics/isolation & purification ; }, abstract = {Enterococci are opportunistic pathogens that can form biofilms during infections and many virulence determinants are involved in this process. Although the virulence factors are often analysed in Enterococcus spp. from humans and food animals, little is known about gut enterococcal isolates from wild birds. Therefore, the determination of virulence factors among enterococci isolated from wild birds may provide new information about a possible source of infection for humans and animals or vice versa via the environment. We analysed different phenotypic and genotypic traits in enterococci from wild birds related to potential virulence in humans and animals and to evaluate biofilm formation and its relationship to virulence genes. The E. faecalis isolates were characterised by greater frequency of biofilm formation in BHI than E. faecium. There was a correlation between hydrophobicity and biofilm formation in BHI broth in E. faecalis. None of the isolates was haemolytic. The presence of some adhesion and gelatinase genes was detected in biofilm-positive isolates. The enterococcal pathogenic factors (esp, hyl, and cyl operon genes) did not seem to be necessary or sufficient for production of biofilm by analysed bacteria. Enterococcus species isolated from wild birds should be considered as a possible source of some virulence determinants.}, } @article {pmid31370119, year = {2019}, author = {Song, YJ and Yu, HH and Kim, YJ and Lee, NK and Paik, HD}, title = {Anti-Biofilm Activity of Grapefruit Seed Extract against Staphylococcus aureus and Escherichia coli.}, journal = {Journal of microbiology and biotechnology}, volume = {29}, number = {8}, pages = {1177-1183}, doi = {10.1041/jmb.1905.05022}, pmid = {31370119}, issn = {1738-8872}, mesh = {Biofilms/*drug effects/growth & development ; Citrus paradisi/*chemistry ; Escherichia coli/*drug effects ; Gentian Violet ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Seeds/*chemistry ; Stainless Steel ; Staphylococcus aureus/*drug effects ; }, abstract = {Grapefruit seed extract (GSE) is a safe and effective preservative that is used widely in the food industry. However, there are few studies addressing the anti-biofilm effect of GSE. In this study, the anti-biofilm effect of GSE was investigated against biofilm-forming strains of Staphylococcus aureus and Escherichia coli. The GSE minimum inhibitory concentration (MIC) for S. aureus and E. coli were 25 μg/ml and 250 μg/ml, respectively. To investigate biofilm inhibition and degradation effect, crystal violet assay and stainless steel were used. Biofilm formation rates of four strains (S. aureus 7, S. aureus 8, E. coli ATCC 25922, and E. coli O157:H4 FRIK 125) were 55.8%, 70.2%, 55.4%, and 20.6% at 1/2 × MIC of GSE, respectively. The degradation effect of GSE on biofilms attached to stainless steel coupons was observed (≥ 1 log CFU/coupon) after exposure to concentrations above the MIC for all strains and 1/2 × MIC for S. aureus 7. In addition, the specific mechanisms of this anti-biofilm effect were investigated by evaluating hydrophobicity, auto-aggregation, exopolysaccharide (EPS) production rate, and motility. Significant changes in EPS production rate and motility were observed in both S. aureus and E. coli in the presence of GSE, while changes in hydrophobicity were observed only in E. coli. No relationship was seen between auto-aggregation and biofilm formation. Therefore, our results suggest that GSE might be used as an anti-biofilm agent that is effective against S. aureus and E. coli.}, } @article {pmid31368074, year = {2019}, author = {Zhou, JH and Yu, HC and Ye, KQ and Wang, HY and Ruan, YJ and Yu, JM}, title = {Optimized aeration strategies for nitrogen removal efficiency: application of end gas recirculation aeration in the fixed bed biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {27}, pages = {28216-28227}, pmid = {31368074}, issn = {1614-7499}, support = {51708499//National Natural Science Foundation of China/ ; 21576241//National Natural Science Foundation of China/ ; 21776262//National Natural Science Foundation of China/ ; 20180533B03//Hangzhou Agricultural and Social Development Research Program/ ; }, mesh = {Bacteria/chemistry/*metabolism ; Biofilms/*growth & development ; Denitrification ; Nitrogen/chemistry/*metabolism ; Waste Disposal, Fluid/*methods ; }, abstract = {Aeration strategy played an important role in reactor performance. In this study, when superficial upflow air velocity (SAV) decreased from 0.16 to 0.08 cm s[-1], low dissolved oxygen concentration (DO) of 2.0 mg L[-1] occurred in reactor. The required depth for anoxic microenvironment in biofilm decreased from 902.3 to 525.9 μm, which enhanced the growth of denitrifying bacteria and total nitrogen (TN) removal efficiency. However, decreasing aeration intensity resulted in insufficient hydraulic shear stress, which led to weak biofilm matrix structure. Mass biofilm detachment and reactor deterioration then occurred after 87 days of operation. An end gas recirculation aeration strategy was proposed to separately manipulate DO and aeration intensity. Low DO and high aeration intensity were simultaneously achieved, which enhanced the metabolism of denitrifying bacteria (such as Flavobacterium sp., Pseudorhodobacter sp., and Dok59 sp.) and EPS-producing bacteria (such as Zoogloea sp. and Rhodobacter sp.). Consequently, high TN removal performance (82.1 ± 2.7%) and stable biofilm structure were achieved.}, } @article {pmid31366707, year = {2019}, author = {Brown, JR and Jurcisek, J and Lakhani, V and Snedden, A and Ray, WC and Mokrzan, EM and Bakaletz, LO and Das, J}, title = {In Silico Modeling of Biofilm Formation by Nontypeable Haemophilus influenzae In Vivo.}, journal = {mSphere}, volume = {4}, number = {4}, pages = {}, pmid = {31366707}, issn = {2379-5042}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Chinchilla ; Computer Simulation ; Ear, Middle/microbiology ; Haemophilus influenzae/classification/*physiology ; *Host Microbial Interactions ; Kinetics ; *Models, Biological ; Monte Carlo Method ; }, abstract = {Biofilms formed by nontypeable Haemophilus influenzae (NTHI) bacteria play an important role in multiple respiratory tract diseases. Visual inspection of the morphology of biofilms formed during chronic infections shows distinct differences from biofilms formed in vitro To better understand these differences, we analyzed images of NTHI biofilms formed in the middle ears of Chinchilla lanigera and developed an in silico agent-based model of the formation of NTHI biofilms in vivo We found that, as in vitro, NTHI bacteria are organized in self-similar patterns; however, the sizes of NTHI clusters in vivo are more than 10-fold smaller than their in vitro counterparts. The agent-based model reproduced these patterns and suggested that smaller clusters occur due to elimination of planktonic NTHI cells by the host responses. Estimation of model parameters by fitting simulation results to imaging data showed that the effects of several processes in the model change during the course of the infection.IMPORTANCE Multiple respiratory illnesses are associated with formation of biofilms within the human airway by NTHI. However, a substantial amount of our understanding of the mechanisms that underlie NTHI biofilm formation is obtained from in vitro studies. Our in silico model that describes biofilm formation by NTHI within the middle ears of Chinchilla lanigera will help isolate processes potentially responsible for the differences between the morphologies of biofilms formed in vivo versus those formed in vitro Thus, the in silico model can be used to glean mechanisms that underlie biofilm formation in vivo and connect those mechanisms to those obtained from in vitro experiments. The in silico model developed here can be extended to investigate potential roles of specific host responses (e.g., mucociliary clearance) on NTHI biofilm formation in vivo The developed computational tools can also be used to analyze and describe biofilm formation by other bacterial species in vivo.}, } @article {pmid31366705, year = {2019}, author = {Kean, R and Ramage, G}, title = {Combined Antifungal Resistance and Biofilm Tolerance: the Global Threat of Candida auris.}, journal = {mSphere}, volume = {4}, number = {4}, pages = {}, pmid = {31366705}, issn = {2379-5042}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida/*drug effects/pathogenicity ; Candidiasis/*microbiology/mortality ; Clinical Trials as Topic ; *Drug Resistance, Multiple, Fungal ; Global Health ; Humans ; Microbial Sensitivity Tests ; }, abstract = {The enigmatic yeast Candida auris has emerged over the last decade and rapidly penetrated our consciousness. The global threat from this multidrug-resistant yeast has generated a call to arms from within the medical mycology community. Over the past decade, our understanding of how this yeast has spread globally, its clinical importance, and how it tolerates and resists antifungal agents has expanded. This review highlights the clinical importance of antifungal resistance in C. auris and explores our current understanding of the mechanisms associated with azole, polyene, and echinocandin resistance. We also discuss the impact of phenotypic tolerance, with particular emphasis on biofilm-mediated resistance, and present new pipelines of antifungal drugs that promise new hope in the management of C. auris infection.}, } @article {pmid31366076, year = {2019}, author = {Ghensi, P and Bettio, E and Maniglio, D and Bonomi, E and Piccoli, F and Gross, S and Caciagli, P and Segata, N and Nollo, G and Tessarolo, F}, title = {Dental Implants with Anti-Biofilm Properties: A Pilot Study for Developing a New Sericin-Based Coating.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {15}, pages = {}, pmid = {31366076}, issn = {1996-1944}, support = {Prot. 24/2015//SIdP (Italian Society of Periodontology and Implantology)/ ; }, abstract = {AIM: several strategies have been tested in recent years to prevent bacterial colonization of dental implants. Sericin, one of the two main silk proteins, possesses relevant biological activities and also literature reports about its potential antibacterial properties, but results are discordant and not yet definitive. The aim of this study was to evaluate the effectiveness of different experimental protocols in order to obtain a sericin-based coating on medical grade titanium (Ti) able to reduce microbial adhesion to the dental implant surface.

MATERIALS AND METHODS: different strategies for covalent bonding of sericin to Ti were pursued throughout a multi-step procedure on Ti-6Al-4V disks. The surface of grade 5 Ti was initially immersed in NaOH solution to obtain the exposure of functional -OH groups. Two different silanization strategies were then tested using aminopropyltriethoxysilane (APTES). Eventually, the bonding between silanized Ti-6Al-4V and sericin was obtained with two different crosslinking processes: glutaraldehyde (GLU) or carbodiimide/N-Hydroxy-succinimide (EDC/NHS). Micro-morphological and compositional analyses were performed on the samples at each intermediate step to assess the most effective coating strategy able to optimize the silanization and bioconjugation processes. Microbiological tests on the coated Ti-6Al-4V disks were conducted in vitro using a standard biofilm producer strain of Staphylococcus aureus (ATCC 6538) to quantify the inhibition of microbial biofilm formation (anti-biofilm efficacy) at 24 hours.

RESULTS: both silanization techniques resulted in a significant increase of silicon (Si) on the Ti-6Al-4V surfaces etched with NaOH. Differences were found between GLU and EDC/NHS bioconjugation strategies in terms of composition, surface micro-morphology and anti-biofilm efficacy. Ti-6Al-4V samples coated with GLU-bound sericin after silanization obtained via vapor phase deposition proved that this technique is the most convenient and effective coating strategy, resulting in a bacterial inhibition of about 53% in respect to the uncoated Ti-6Al-4V disks.

CONCLUSIONS: The coating with glutaraldehyde-bound sericin after silanization in the vapor phase showed promising bacterial inhibition values with a significant reduction of S. aureus biofilm. Further studies including higher number of replicates and more peri-implant-relevant microorganisms are needed to evaluate the applicability of this experimental protocol to dental implants.}, } @article {pmid31364079, year = {2019}, author = {Lora-Tamayo, J and Murillo, O and Ariza, J}, title = {Clinical Use of Colistin in Biofilm-Associated Infections.}, journal = {Advances in experimental medicine and biology}, volume = {1145}, number = {}, pages = {181-195}, doi = {10.1007/978-3-030-16373-0_13}, pmid = {31364079}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Bone Diseases, Infectious/drug therapy ; Central Nervous System Infections/drug therapy ; Colistin/*therapeutic use ; Cystic Fibrosis/microbiology ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.}, } @article {pmid31363870, year = {2019}, author = {Piotrowski, M and Wultańska, D and Obuch-Woszczatyński, P and Pituch, H}, title = {Fructooligosaccharides and mannose affect Clostridium difficile adhesion and biofilm formation in a concentration-dependent manner.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {38}, number = {10}, pages = {1975-1984}, pmid = {31363870}, issn = {1435-4373}, support = {UMO:2017/25/N/NZ6/01763//Narodowe Centrum Nauki/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Cell Line ; Clostridioides difficile/*drug effects ; Epithelial Cells/microbiology ; Humans ; Locomotion/drug effects ; Mannose/*pharmacology ; Oligosaccharides/*pharmacology ; *Prebiotics ; }, abstract = {The aim of this study was to investigate the effects that prebiotic and candidates for prebiotics on Clostridium difficile strains to adhere to various human epithelial cell lines and to compare the adhesive properties of specific C. difficile strains. We also sought to examine the effect of different concentrations of fructooligosaccharides and mannose on the formation of biofilms by C. difficile strains. The influence of cellobiose, fructooligosaccharides, inulin, mannose, and raffinose on the adherence properties of various C. difficile strains, including motile 630, non-motile M120, and 10 clinical motile ribotype 027 strains, to non-mucous secreting HT-29, mucous secreting HT-29 MXT, and CCD 841 CoN cells lines. The most effective prebiotics were used in biofilm formation assays. We demonstrated that all C. difficile strains adhered to all cell lines. However, the C. difficile M120 non-motile strain was statistically more likely to adhere to all three cell lines (CFU median, 40) compared to the motile strains (CFU median, 3; p < 0.001). Furthermore, among the carbohydrates examined, only fructooligosaccharides and mannose were found to significantly decrease adhesion (p < 0.001) of C. difficile strains. Alternatively, using a biofilm assay, we observed, via confocal laser scanning microscopy, that sub-inhibitory concentrations (1%) of fructooligosaccharides and mannose functioned to increase biofilm formation by C. difficile. We demonstrated that specific prebiotics and candidate prebiotics exhibit varying anti-adhesive properties towards C. difficile in vitro and that treatment with sub-inhibitory concentrations of prebiotics can cause an increase in biofilm formation by C. difficile.}, } @article {pmid31363032, year = {2019}, author = {Orazi, G and Ruoff, KL and O'Toole, GA}, title = {Pseudomonas aeruginosa Increases the Sensitivity of Biofilm-Grown Staphylococcus aureus to Membrane-Targeting Antiseptics and Antibiotics.}, journal = {mBio}, volume = {10}, number = {4}, pages = {}, pmid = {31363032}, issn = {2150-7511}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; T32 AI007519/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; }, abstract = {Pseudomonas aeruginosa and Staphylococcus aureus often cause chronic, recalcitrant infections in large part due to their ability to form biofilms. The biofilm mode of growth enables these organisms to withstand antibacterial insults that would effectively eliminate their planktonic counterparts. We found that P. aeruginosa supernatant increased the sensitivity of S. aureus biofilms to multiple antimicrobial compounds, including fluoroquinolones and membrane-targeting antibacterial agents, including the antiseptic chloroxylenol. Treatment of S. aureus with the antiseptic chloroxylenol alone did not decrease biofilm cell viability; however, the combination of chloroxylenol and P. aeruginosa supernatant led to a 4-log reduction in S. aureus biofilm viability compared to exposure to chloroxylenol alone. We found that the P. aeruginosa-produced small molecule 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO) is responsible for the observed heightened sensitivity of S. aureus to chloroxylenol. Similarly, HQNO increased the susceptibility of S. aureus biofilms to other compounds, including both traditional and nontraditional antibiotics, which permeabilize bacterial membranes. Genetic and phenotypic studies support a model whereby HQNO causes an increase in S. aureus membrane fluidity, thereby improving the efficacy of membrane-targeting antiseptics and antibiotics. Importantly, our data show that P. aeruginosa exoproducts can enhance the ability of various antimicrobial agents to kill biofilm populations of S. aureus that are typically difficult to eradicate. Finally, our discovery that altering membrane fluidity shifts antimicrobial sensitivity profiles of bacterial biofilms may guide new approaches to target persistent infections, such as those commonly found in respiratory tract infections and in chronic wounds.IMPORTANCE The thick mucus in the airways of cystic fibrosis (CF) patients predisposes them to frequent, polymicrobial respiratory infections. Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from the airways of individuals with CF, as well as from diabetic foot ulcers and other wounds. Both organisms form biofilms, which are notoriously difficult to eradicate and promote chronic infection. In this study, we have shown that P. aeruginosa-secreted factors can increase the efficacy of compounds that alone have little or no bactericidal activity against S. aureus biofilms. In particular, we discovered that P. aeruginosa exoproducts can potentiate the antistaphylococcal activity of phenol-based antiseptics and other membrane-active drugs. Our findings illustrate that polymicrobial interactions can dramatically increase antibacterial efficacy in vitro and suggest that altering membrane physiology promotes the ability of certain drugs to kill bacterial biofilms-knowledge that may provide a path for the discovery of new biofilm-targeting antimicrobial strategies.}, } @article {pmid31362660, year = {2020}, author = {Jain, N and Mansuri, A}, title = {Stopping the Unstoppable: Unconventional Methods to Prevent the Biofilm Growth.}, journal = {Current drug discovery technologies}, volume = {17}, number = {4}, pages = {515-522}, doi = {10.2174/1570163816666190726153441}, pmid = {31362660}, issn = {1875-6220}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacteria/drug effects/pathogenicity/virology ; Bacterial Infections/microbiology/*therapy ; Bacterial Outer Membrane/drug effects ; Bacterial Proteins/antagonists & inhibitors/metabolism ; Biofilms/*drug effects ; Cell Wall ; Chelating Agents/pharmacology/therapeutic use ; Drug Resistance, Bacterial/drug effects ; Humans ; Nanoparticles/therapeutic use ; Phage Therapy/*methods ; Polysaccharides, Bacterial/pharmacology/therapeutic use ; Pore Forming Cytotoxic Proteins/pharmacology/therapeutic use ; Protein Multimerization/drug effects ; }, abstract = {Biofilms are consortia of microorganisms encased in extracellular matrix that protect cells from adverse conditions. A biofilm matrix is typically composed of extracellular DNA, cellulose and proteinaceous amyloid fibers. The matrix aids in adhesion to abiotic and biotic surface including medical devices and host tissues. The presence of biofilm makes bacteria more resilient and non-responsive to most current treatment regimes at disposal. Therefore, biofilm-associated infections are serious threat in hospital settings and pose a huge burden on economy. Inhibition of matrix components (cellulose and/or amyloid formation) has emerged as a lucrative alternative strategy to cure biofilm-related infections and combat antibiotic resistance. Here we review the current and emerging therapeutic interventions to mitigate persistent infections due to biofilms. The successful implementation of these interventions will have a huge impact on alleviating the current financial burden on healthcare services.}, } @article {pmid31362602, year = {2019}, author = {Hirayama, S and Nojima, N and Furukawa, S and Ogihara, H and Morinaga, Y}, title = {Steric microstructure of mixed-species biofilm formed by interaction between Lactobacillus plantarum ML11-11 and Saccharomyces cerevisiae.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {83}, number = {12}, pages = {2386-2389}, doi = {10.1080/09168451.2019.1649978}, pmid = {31362602}, issn = {1347-6947}, mesh = {Bacterial Adhesion ; *Biofilms ; Lactobacillus plantarum/*physiology ; Microscopy, Atomic Force ; Saccharomyces cerevisiae/*physiology ; }, abstract = {The mixed-species biofilm of Lactobacillus plantarum ML11-11 (LAB) and yeast had a double-layered structure with the ground layer composed of LAB cells, and the upper layer composed of coaggregates of LAB and yeast cells. The ability of LAB to adhere to both, the solid surface and the yeast cells, enabled the formation and maintenance of the biofilm as an ecosystem for LAB and yeast.}, } @article {pmid31362224, year = {2019}, author = {Ashkanani, A and Almomani, F and Khraisheh, M and Bhosale, R and Tawalbeh, M and AlJaml, K}, title = {Bio-carrier and operating temperature effect on ammonia removal from secondary wastewater effluents using moving bed biofilm reactor (MBBR).}, journal = {The Science of the total environment}, volume = {693}, number = {}, pages = {133425}, doi = {10.1016/j.scitotenv.2019.07.231}, pmid = {31362224}, issn = {1879-1026}, mesh = {Ammonia/*analysis ; Biofilms ; *Bioreactors ; Kinetics ; Temperature ; Waste Disposal, Fluid/*methods ; Wastewater/*analysis ; }, abstract = {This study investigates the impact of bio-carriers' surface area and shape, wastewater chemistry and operating temperature on ammonia removal from real wastewater effluents using Moving bed biofilm reactors (MBBRs) operated with three different AnoxKaldness bio-carriers (K3, K5, and M). The study concludes the surface area loading rate, specific surface area, and shape of bio-carrier affect ammonia removal under real conditions. MBBR kinetics and sensitivity for temperature changes were affected by bio-carrier type. High surface area bio-carriers resulted in low ammonia removal and bio-carrier clogging. Significant ammonia removals of 1.420 ± 0.06 and 1.103 ± 0.06 g - N/m[2]. d were achieved by K3(As = 500 m[2]/m[3]) at 35 and 20 °C, respectively. Lower removals were obtained by high surface area bio-carrier K5 (1.123 ± 0.06 and 0.920 ± 0.06 g - N/m[2]. d) and M (0.456 ± 0.05 and 0.295 ± 0.05 g - N/m[2]. d) at 35 and 20 °C, respectively. Theta model successfully represents ammonia removal kinetics with θ values of 1.12, 1.06 and 1.13 for bio-carrier K3, K5 and M respectively. MBBR technology is a feasible choice for treatment of real wastewater effluents containing high ammonia concentrations.}, } @article {pmid31362109, year = {2019}, author = {Sayar, F and Chiniforush, N and Bahador, A and Etemadi, A and Akhondi, N and Azimi, C}, title = {Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {462-466}, doi = {10.1016/j.pdpdt.2019.07.012}, pmid = {31362109}, issn = {1873-1597}, mesh = {Aggregatibacter actinomycetemcomitans/*drug effects ; Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Humans ; Indocyanine Green/pharmacology ; Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Stem Cells ; Titanium ; Tolonium Chloride/pharmacology ; }, abstract = {BACKGROUND: Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs.

MATERIALS AND METHODS: Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test.

RESULTS: Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05).

CONCLUSION: Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.}, } @article {pmid31360725, year = {2019}, author = {Leonhard, M and Zatorska, B and Moser, D and Schneider-Stickler, B}, title = {Growth Media for Mixed Multispecies Oropharyngeal Biofilm Compositions on Silicone.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {8051270}, pmid = {31360725}, issn = {2314-6141}, mesh = {Biofilms/drug effects/growth & development ; Candida/*growth & development/pathogenicity ; Culture Media/chemistry/*pharmacology ; Humans ; Laryngectomy ; Larynx, Artificial/*microbiology ; Oropharynx/drug effects/*microbiology ; Silicones/chemistry/therapeutic use ; }, abstract = {AIMS: Microbial colonization of silicone voice prostheses by bacteria and Candida species limits the device lifetime of modern voice prostheses in laryngectomized patients. Thus, research focuses on biofilm inhibitive properties of novel materials, coatings, and surface enhancements. Goal of this in vitro study was the evaluation of seven commonly used growth media to simulate growth of mixed oropharyngeal species as mesoscale biofilms on prosthetic silicone for future research purposes.

METHODS AND RESULTS: Yeast Peptone Dextrose medium (YPD), Yeast Nitrogen Base medium (YNB), M199 medium, Spider medium, RPMI 1640 medium, Tryptic Soy Broth (TSB), and Fetal Bovine Serum (FBS) were used to culture combined mixed Candida strains and mixed bacterial-fungal compositions on silicone over the period of 22 days. The biofilm surface spread and the microscopic growth showed variations from in vivo biofilms depending on the microbial composition and growth medium.

CONCLUSION: YPD and FBS prove to support continuous in vitro growth of mixed bacterial-fungal oropharyngeal biofilms deposits over weeks as needed for longterm in vitro testing with oropharyngeal biofilm compositions.

The study provides data on culture conditions for mixed multispecies biofilm compositions that can be used for future prosthesis designs.}, } @article {pmid31357945, year = {2019}, author = {Ramos, JN and Souza, C and Faria, YV and da Silva, EC and Veras, JFC and Baio, PVP and Seabra, SH and de Oliveira Moreira, L and Hirata Júnior, R and Mattos-Guaraldi, AL and Vieira, VV}, title = {Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum.}, journal = {BMC infectious diseases}, volume = {19}, number = {1}, pages = {672}, pmid = {31357945}, issn = {1471-2334}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteremia/epidemiology/*microbiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Catheter-Related Infections/epidemiology/*microbiology ; Corynebacterium/drug effects/genetics/*physiology ; Corynebacterium Infections/epidemiology/*microbiology ; Cross Infection ; *Disease Outbreaks ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Female ; Genotyping Techniques ; Humans ; Male ; Microbial Sensitivity Tests ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; }, abstract = {BACKGROUND: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.

METHODS: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.

RESULTS: Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.

CONCLUSIONS: Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.}, } @article {pmid31357240, year = {2019}, author = {Feng, G and Cheng, Y and Worobo, RW and Borca-Tasciuc, DA and Moraru, CI}, title = {Nanoporous anodic alumina reduces Staphylococcus biofilm formation.}, journal = {Letters in applied microbiology}, volume = {69}, number = {4}, pages = {246-251}, doi = {10.1111/lam.13201}, pmid = {31357240}, issn = {1472-765X}, support = {65210-20024-11//USDA-NIFA/ ; DMR-1120296//NSF MRSEC/ ; 1S10RR025502-01/GF/NIH HHS/United States ; ECS-9876771//NSF/ ; }, mesh = {Aluminum Oxide/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*growth & development ; Nanopores ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*growth & development ; Staphylococcus epidermidis/*growth & development ; }, abstract = {Staphylococcus epidermidis and Staphylococcus aureus, two bacterial strains commonly associated with biofilm-related medical infections and food poisoning, can rapidly colonize biotic and abiotic surfaces. The present study investigates the ability of anodic alumina surfaces with nanoporous surface topography to minimize the attachment and biofilm formation mediated by these pathogenic bacterial strains. Early attachment and subsequent biofilm development were retarded on surfaces with nanopores of 15-25 nm in diameter compared to surfaces with 50-100 nm pore diameter and nanosmooth surfaces. After 30 min of incubation in nutritive media, the biomass accumulation per unit surface area was 2·93 ± 1·72 µm[3] µm[-2] for the 15 nm, 3·49 ± 1·97 µm[3] µm[-2] for the 25 nm, as compared to 14·04 ± 6·39 µm[3] µm[-2] for the nanosmooth, 11·88 ± 9·72 µm[3] µm[-2] for the 50 nm and 12·09 ± 11·84 µm[3] µm[-2] for the 100 nm surfaces respectively. These findings suggest that anodic alumina with small size nanoscale pores could reduce the incidence of staphylococcal biofilms and infections, and shows promise as a material for a variety of medical applications and food contact surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper reports on a simple, robust and scientifically sound method to reduce attachment and biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis to abiotic surfaces using a carefully designed nanoscale topography. This approach can help to reduce the incidence of staphylococcal biofilms and infections without imposing selective stresses on bacteria, thus preventing the creation of resistant strains.}, } @article {pmid31356873, year = {2019}, author = {Lee, HH and Del Pozzo, J and Salamanca, SA and Hernandez, H and Martinez, LR}, title = {Reduced phagocytosis and killing of Cryptococcus neoformans biofilm-derived cells by J774.16 macrophages is associated with fungal capsular production and surface modification.}, journal = {Fungal genetics and biology : FG & B}, volume = {132}, number = {}, pages = {103258}, pmid = {31356873}, issn = {1096-0937}, support = {R01 AI145559/AI/NIAID NIH HHS/United States ; R25 GM069621/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Antibodies, Monoclonal ; Binding Sites, Antibody ; Biofilms/*growth & development ; Cell Line ; Cryptococcus neoformans/genetics/*physiology ; Fungal Capsules/genetics/*physiology ; Fungal Polysaccharides/biosynthesis ; Immune Evasion ; Macrophages/immunology/*microbiology ; Mice ; *Phagocytosis ; }, abstract = {Cryptococcus neoformans is an opportunistic encapsulated pathogen that causes life-threatening meningoencephalitis in individuals with immunosuppression. We compared the interactions of C. neoformans planktonic and biofilm-derived cells with J774.16 macrophage-like cells. Planktonic cells are more phagocytized and killed by J774.16 cells than biofilm-derived fungal cells. Biofilm-derived cryptococci possess larger capsule size and release significantly more capsular polysaccharide than planktonic cells in culture. Biofilm-derived fungi exhibited upregulation of genes involved in capsular production. Capsular-specific monoclonal antibody 18B7 demonstrated differential binding to the surface of planktonic and biofilm-derived cryptococci providing a plausible strategy for fungal evasion of macrophages and persistence. Future studies are necessary to elucidate how C. neoformans biofilm-derived cells regulate their virulence factors when interacting with cells of the immune system.}, } @article {pmid31355999, year = {2019}, author = {Chuang, PJ and Swaminathan, V and Pavlovsky, L and Marquez-Catral, L and Jones, DL and Song, L}, title = {Negative influence of biofilm on CoCrMo corrosion.}, journal = {Journal of biomedical materials research. Part A}, volume = {107}, number = {11}, pages = {2556-2566}, doi = {10.1002/jbm.a.36761}, pmid = {31355999}, issn = {1552-4965}, mesh = {Alloys ; Biofilms/*drug effects/growth & development ; Corrosion ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; Titanium/chemistry/pharmacology ; Vitallium/chemistry/*pharmacology ; }, abstract = {Minimal studies exist investigating biofilm-induced corrosion of orthopaedic implants. This study investigates potential contributions of Pseudomonas aeruginosa and Staphylococcus aureus biofilms on corrosion resistance of CoCrMo under static and fretting conditions. Biofilms were cultured on CoCrMo coupons for either 4 weeks (static culture) or 6 days (fretting culture; pin-on-disk with a Ti6Al4V hemispherical tip pin). Morphology of biofilms and corrosion of coupon surfaces were analyzed via SEM. Open circuit potential and electrochemical impedance spectroscopy measurements were collected for corrosion performance evaluation. Results showed no visible corrosion on coupon surfaces in static culture, which suggests these biofilms alone do not induce severe corrosion under the conditions of this study. However, electrochemical data showed biofilm presence lowered coupon electrochemical impedance in static and fretting cultures, suggesting resistive and capacitive characteristics of the metal oxide-biofilm-media interface were altered. Under fretting, the P. aeruginosa group exhibited a distinct damage morphology and Co:Cr:Mo ratio within the wear scar when compared with S. aureus and the bacteria-free control. These differences suggest the presence of P. aeruginosa biofilms may negatively impact corrosion resistance at the fretting interface. Taken together these results demonstrate biofilms can contribute to implant corrosion by influencing the electrochemical impedance of implant metal surfaces.}, } @article {pmid31354823, year = {2019}, author = {Cunha, EJ and Auersvald, CM and Deliberador, TM and Gonzaga, CC and Esteban Florez, FL and Correr, GM and Storrer, CLM}, title = {Effects of Active Oxygen Toothpaste in Supragingival Biofilm Reduction: A Randomized Controlled Clinical Trial.}, journal = {International journal of dentistry}, volume = {2019}, number = {}, pages = {3938214}, pmid = {31354823}, issn = {1687-8728}, abstract = {Gingivitis is still considered a major risk factor for the occurrence and progression of periodontal disease. The aim of the present study was to compare the long-term (1, 12, and 18 weeks) antiplaque and antigingivitis efficacies of two commercially available toothpastes, Colgate Total[®] (CT) and BlueM[®] (BM), against attached supragingival dental plaque and gingival inflammation in an experimental gingivitis model. A parallel double-blinded randomized clinical trial including 39 dental students who refrained from all plaque control methods (manual or chemical) for 7 days was conducted. After the establishment of clinical gingivitis, participants were randomized into two experimental groups (CT and BM). Plaque index (PI) and gingival index (GI) were then calculated according to Turesky's modified Quigley and Hein index. Participants were assessed in four time periods (preclinical trial phase (W -1), gingivitis phase (W0), one week (W1), twelve weeks (W12), and eighteen weeks (W18)). Participants' stimulated saliva was collected and cultured (either aerobically or anaerobically, 37°C, 48 hours) in each time period (W -1, W0, W1, W12, and W18) for the count of viable colonies. Obtained data were analyzed using 2-way ANOVA and Tukey's test (α = 0.05). No significant differences were found (p > 0.05) between experimental groups at W -1. Significant differences between groups were observed at W0 (p < 0.05) for the parameter time period, but not for the interaction between parameters (time period ∗ toothpastes). Lower bacterial counts were observed in both groups after one week of toothbrushing; however, no significant differences were found between investigated dentifrices. Intra- and intergroup comparisons revealed that significant differences were not found (p > 0.05) between dentifrices at W1, W12, and W18 for both GI and PI. The present study demonstrated that toothpastes containing active oxygen and lactoferrin (BM) have comparable antiplaque and antigingivitis efficacies with triclosan-containing toothpastes (CT).}, } @article {pmid31354319, year = {2019}, author = {Abd El-Baky, RM and Sandle, T and John, J and Abuo-Rahma, GEA and Hetta, HF}, title = {A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {1703-1718}, pmid = {31354319}, issn = {1178-6973}, abstract = {Background: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure. Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus. Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily). Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.}, } @article {pmid31352165, year = {2019}, author = {Riegler, P and Bieringer, E and Chrusciel, T and Stärz, M and Löwe, H and Weuster-Botz, D}, title = {Continuous conversion of CO2/H2 with Clostridium aceticum in biofilm reactors.}, journal = {Bioresource technology}, volume = {291}, number = {}, pages = {121760}, doi = {10.1016/j.biortech.2019.121760}, pmid = {31352165}, issn = {1873-2976}, mesh = {Acetic Acid/metabolism ; *Biofilms ; *Bioreactors ; Carbon Dioxide/*metabolism ; Clostridium/*physiology ; Fermentation ; Hydrogen/*metabolism ; }, abstract = {A lab-scale stirred-tank bioreactor was reversibly retrofitted to a packed-bed and a trickle-bed biofilm reactor to study and compare the conversion of CO2/H2 with immobilised Clostridiumaceticum. The biofilm reactors were characterised and their functionality confirmed. Up to 8.6 g of C. aceticum were immobilised onto 300 g sintered ceramic carrier material, proving biofilm formation to be a robust means for cell retention of C. aceticum. Continuous CO2/H2-fermentation studies were performed with both biofilm reactor configurations as function of dilution rates, partial gas pressures and gas flow rates. The experiments showed that in the packed-bed biofilm reactor, the acetate space-time yield was independent of the dilution rate, because of low H2 gas-liquid mass transfer rates (≤17 mmol H2 L[-1] h[-1]). The continuous operation of the trickle-bed biofilm reactor increased the gas-liquid mass transfer rates to up to 56 mmol H2 L[-1] h[-1]. Consequently, the acetate space-time yield of up to 14 mmol acetate L[-1] h[-1] was improved 3-fold at hydrogen conversions of up to 96%.}, } @article {pmid31351106, year = {2019}, author = {Bautista-Hernández, LA and Gómez-Olivares, JL and Buentello-Volante, B and Dominguez-Lopez, A and Garfias, Y and Acosta-García, MC and Calvillo-Medina, RP and Bautista-de Lucio, VM}, title = {Negative interaction of Staphylococcus aureus on Fusarium falciforme growth ocular isolates in an in vitro mixed biofilm.}, journal = {Microbial pathogenesis}, volume = {135}, number = {}, pages = {103644}, doi = {10.1016/j.micpath.2019.103644}, pmid = {31351106}, issn = {1096-1208}, mesh = {Acetic Acid ; Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Biomass ; Chitin ; Eye/*microbiology ; Fusarium/drug effects/*growth & development ; Humans ; Hydrogen-Ion Concentration ; Lactic Acid ; Microbial Interactions/*physiology ; Microbial Viability/drug effects ; Mycelium ; Spores, Fungal ; Staphylococcus aureus/*physiology ; }, abstract = {The interactions between prokaryotes and eukaryotes are abundant in nature. These microorganisms also interact in the human body. Fungal-bacteria interactions are present in many diseases. In this study, we evaluated the microbial interaction of Fusarium falciforme and Staphylococcus aureus developing mixed biofilm in vitro. When both microorganisms grew up together the mixed biofilm biomass decreased than F. falciforme monobiofilm biomass. S. aureus was able to interact and form aggregates over the mycelium and conidia surface of F. falciforme. Our results suggest that S. aureus could bind to colloidal chitin. On another hand, the supernatants from S. aureus biofilm and S. aureus-F. falciforme presented an antifungal effect over F. falciforme biofilm formation. Finally we found that the pH had an inhibitory effect over fungal biofilm formation. We concluded that S. aureus can affect the F. falciforme growth negatively in mixed biofilm involving factors like pH, supernatants compounds, anchor to chitin, and bacterial viability.}, } @article {pmid31350606, year = {2019}, author = {Schopf, A and Delatolla, R and Kirkwood, KM}, title = {Partial nitritation at elevated loading rates: design curves and biofilm characteristics.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {11}, pages = {1809-1818}, doi = {10.1007/s00449-019-02177-8}, pmid = {31350606}, issn = {1615-7605}, support = {497995-2017//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Ammonia/metabolism ; Biofilms/*growth & development ; *Bioreactors ; Kinetics ; *Models, Biological ; *Nitrification ; Oxygen/metabolism ; }, abstract = {There is a need to develop low operational intensity, cost-effective, and small-footprint systems to treat wastewater. Partial nitritation has been studied using a variety of control strategies, however, a gap in passive operation is evident. This research investigates the use of elevated loading rates as a strategy for achieving low operational intensity partial nitritation in a moving bed biofilm reactor (MBBR) system. The effects of loading rates on nitrification kinetics and biofilm characteristics were determined at elevated, steady dissolved oxygen concentrations between 5.5 and 7.0 mg O2/L and ambient temperatures between 19 and 21 °C. Four elevated loading rates (3, 4, 5 and 6.5 g NH4[+]-N/m[2] days) were tested with a distinct shift in kinetics being observed towards nitritation at elevated loadings. Complete partial nitritation (100% nitrite production) was achieved at 6.5 g NH4[+]-N/m[2] days, likely due to thick biofilm (572 µm) and elevated NH4[+]-N load, which resulted in suppression of nitrite oxidation.}, } @article {pmid31349525, year = {2019}, author = {Ismail, NA and Amin, KAM and Majid, FAA and Razali, MH}, title = {Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {103}, number = {}, pages = {109770}, doi = {10.1016/j.msec.2019.109770}, pmid = {31349525}, issn = {1873-0191}, mesh = {3T3 Cells ; Animals ; *Anti-Bacterial Agents/chemistry/pharmacology ; *Bandages ; Escherichia coli/*growth & development ; *Membranes, Artificial ; Mice ; Nanoparticles/*chemistry ; *Polysaccharides, Bacterial/chemistry/pharmacology ; Rats ; Rats, Sprague-Dawley ; Staphylococcus aureus/*growth & development ; *Titanium/chemistry/pharmacology ; Wound Healing/*drug effects ; }, abstract = {In this work, the potential of titanium dioxide nanoparticles incorporated gellan gum (GG + TiO2-NPs) biofilm as wound dressing material was investigated. The GG + TiO2-NPs biofilm was prepared via evaporative casting technique and was characterized using FTIR, XRD, and SEM to study their physiochemical properties. The mechanical properties, swelling and water vapor transmission rate (WVTR) of biofilm was determined to comply with an ideal wound dressing material. In vitro and in vivo wound healing studies was carried out to evaluate the performance of GG + TiO2-NPs biofilm. In vitro wound healing was studied on 3 T3 mouse fibroblast cells for cell viability, cell proliferation, and scratch assay. The acridine orange/propidium iodide (AO/PI) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to evaluate the viability of cell and cell proliferation. Cell migration assay was analyzed using Essen BioScience IncuCyteTM Zoom system. In vivo wound healing via open excision wounds model on Sprague Dawley rat was studied within 14 days. The FT-IR spectra of GG + TiO2-NPs biofilm show main bands assigned to OH stretching, OH deformation, and TiO stretching modes. XRD pattern of GG + TiO2-NPs biofilm suggesting that TiO2-NPs was successfully incorporated in biofilm and well distributed on the surface as proved by SEM analysis. The GG + TiO2-NPs biofilm shows higher mechanical strength and swelling (3.76 ± 0.11 MPa and 1061 ± 6%) as compared to pure GG film (3.32 ± 0.08 Mpa and 902 ± 6%), respectively. GG + TiO2-NPs biofilm shows good antibacterial properties as 9 ± 0.25 mm and 11 ± 0.06 mm exhibition zone was observed against Staphylococcus aureus and Escherichia coli bacteria, respectively. While no exhibition zone was obtained for pure GG biofilm. GG + TiO2-NPs biofilm also demonstrated better cell-to-cell interaction properties, as it's promoted cell proliferation and cell migration to accelerate open excision wound healing on Sprague Dawley rat. The wound treated with GG + TiO2-NPs biofilm was healed within 14 days, on the other hand, the wound is still can be seen when it was treated with GG. However, GG and GG + TiO2-NPs biofilm show no cytotoxicity effects on mouse fibroblast cells.}, } @article {pmid31349520, year = {2019}, author = {Vögeling, H and Plenagl, N and Seitz, BS and Duse, L and Pinnapireddy, SR and Dayyoub, E and Jedelska, J and Brüßler, J and Bakowsky, U}, title = {Synergistic effects of ultrasound and photodynamic therapy leading to biofilm eradication on polyurethane catheter surfaces modified with hypericin nanoformulations.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {103}, number = {}, pages = {109749}, doi = {10.1016/j.msec.2019.109749}, pmid = {31349520}, issn = {1873-0191}, mesh = {Anthracenes ; Biofilms/drug effects/growth & development ; Catheter-Related Infections/*microbiology/therapy ; Cell Line ; Central Venous Catheters/*microbiology ; Humans ; Materials Testing ; Nanostructures/chemistry ; Perylene/*analogs & derivatives/chemistry/pharmacology ; Photochemotherapy/*methods ; Polyurethanes ; Reactive Oxygen Species/metabolism ; Staphylococcus/drug effects/pathogenicity/physiology ; Surface Properties ; Ultrasonics/*methods ; }, abstract = {Catheter related infections are causing one third of all blood stream infections. The mortality of those infections is very high and the gold standard for catheter related blood stream infections (CR-BSI) is still the removal of the catheter and systemic antibiotic therapy. There already exist some approaches to prevent the biofilm formation on catheter material, which are far from ideal. A new strategy to prevent bacterial colonization on catheter surfaces is the application of photodynamic therapy (PDT). Therefor the surface has to be modified with substances that can be activated by light, leading to the production of cell toxic reactive oxygen species (ROS). Only small concentrations of the so called photosensitizer (PS) are necessary, avoiding side effects in human therapy. Furthermore, there is no resistance development in PDT. In this study polyurethane (PUR) surfaces were coated with hypericin nanoformulations, leading to 4.3 log10 reduction in bacterial growth in vitro. The effect could be enhanced by the application of ultrasound. The combination of PDT with ultrasound therapy led to a synergistic effect resulting in a 6.8 log10 reduction of viable counts. This minimal invasive method requires only an optical fibre inserted in the catheter lumen and an ultrasound device. Thus the implementation in daily clinical practice is very simple.}, } @article {pmid31349502, year = {2019}, author = {Torres-Rêgo, M and Gláucia-Silva, F and Rocha Soares, KS and de Souza, LBFC and Damasceno, IZ and Santos-Silva, ED and Lacerda, AF and Chaves, GM and Silva-Júnior, AAD and Fernandes-Pedrosa, MF}, title = {Biodegradable cross-linked chitosan nanoparticles improve anti-Candida and anti-biofilm activity of TistH, a peptide identified in the venom gland of the Tityus stigmurus scorpion.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {103}, number = {}, pages = {109830}, doi = {10.1016/j.msec.2019.109830}, pmid = {31349502}, issn = {1873-0191}, mesh = {Animals ; *Antifungal Agents/chemistry/pharmacology ; *Arthropod Proteins/chemistry/pharmacology ; Candida/*growth & development ; *Chitosan/chemistry/pharmacology ; Chlorocebus aethiops ; Mice ; Nanoparticles/*chemistry ; *Peptides/chemistry/pharmacology ; RAW 264.7 Cells ; Scorpion Venoms/*chemistry ; Scorpions/*chemistry ; Vero Cells ; }, abstract = {Among several bioactive peptides identified from the venom glands of the Tityus stigmurus scorpion, one peptide with hypotensive action (TistH, Tityus stigmurus Hypotensin) showed multifunctional and biotechnological applications. The maximum efficacy of this class of compounds can be achieved by immobilizing it in specific and suitable biomaterials or suitable carriers. In this study, distinct entrapment methods of TistH in chitosan nanoparticles was tested using its incorporation (CN-TistH-Inc) or adsorption (CN-TistH-Ads) methods by ionotropic gelification. Physico-chemical properties as well as biocompatibility and antifungal efficacy were assessed for different samples. Atomic force microscopy and field emission gun scanning electronic microscopy images associated with particle size measurements demonstrated that the two methods induced cationic spherical, small (< 160 nm), and narrow-sized (PdI about 0.3) nanoparticles, even after peptide loading greater than 96.5%, which was confirmed using Fourier transform infrared spectroscopy. The colloidal suspensions showed to be stable for 8 weeks and were able to induce the desired slow in vitro peptide release. Cytotoxicity assays performed in normal cells originated from murine macrophages (RAW 264.7) and kidneys of African green monkeys (Vero E6) suggested biocompatibility of samples. The CN-TistH-Inc and CN-TistH-Ads showed a minimal inhibitory concentration of 89.2 μg.mL[-1] against Candida albicans, 11.1 μg.mL[-1] for C. parapsilosis and C. tropicalis, confirmed by minimum fungicidal concentrations assay. Moreover, the TistH-loaded cross-linked chitosan nanoparticles significantly reduced the biofilm formation of clinical yeast sepsis of C. tropicalis and C. krusei, as well as clinical yeasts of vulvovaginal candidiasis of C. albicans. In this approach, biodegradable nanocarriers prepared using simple and reproducible methods demonstrated the ability to deliver the TistH peptide from T. stigmurus and improve its antifungal efficacy.}, } @article {pmid31349480, year = {2019}, author = {Hasan, N and Cao, J and Lee, J and Naeem, M and Hlaing, SP and Kim, J and Jung, Y and Lee, BL and Yoo, JW}, title = {PEI/NONOates-doped PLGA nanoparticles for eradicating methicillin-resistant Staphylococcus aureus biofilm in diabetic wounds via binding to the biofilm matrix.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {103}, number = {}, pages = {109741}, doi = {10.1016/j.msec.2019.109741}, pmid = {31349480}, issn = {1873-0191}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Azo Compounds/chemistry ; Biofilms/drug effects ; Diabetes Complications/*drug therapy/microbiology ; Diabetes Mellitus, Experimental/complications/microbiology ; Drug Liberation ; Male ; Methicillin-Resistant Staphylococcus aureus/*drug effects/pathogenicity ; Mice, Inbred BALB C ; Mice, Inbred ICR ; Nanoparticles/*chemistry ; Nitric Oxide/pharmacokinetics ; Polyethyleneimine/chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry ; Staphylococcal Skin Infections/complications/*drug therapy ; Wound Healing/drug effects ; Wounds and Injuries/complications/*drug therapy/microbiology/pathology ; }, abstract = {Wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilm represent a high risk in patients with diabetes. Nitric oxide (NO) has shown promise in dispersing biofilm and wound healing. For an effective treatment of MRSA biofilm-infected wounds, however, NO needs to be supplied to the biofilm matrix in a sustainable manner due to a short half-life and limited diffusion distance of NO. In this study, polyethylenimine/diazeniumdiolate (PEI/NONOate)-doped PLGA nanoparticles (PLGA-PEI/NO NPs) with an ability to bind to the biofilm matrix are developed to facilitate the NO delivery to MRSA biofilm-infected wound. In simulated wound fluid, PLGA-PEI/NO NPs show an extended NO release over 4 days. PLGA-PEI/NO NPs firmly bind to the MRSA biofilm matrix, resulting in a greatly enhanced anti-biofilm activity. Moreover, PLGA-PEI/NO NPs accelerate healing of MRSA biofilm-infected wounds in diabetic mice along with complete biofilm dispersal and reduced bacterial burden. These results suggest that the biofilm-binding NO-releasing NPs represent a promising NO delivery system for the treatments of biofilm-infected chronic wounds.}, } @article {pmid31349180, year = {2019}, author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA}, title = {Moving bed biofilm reactor technology in municipal wastewater treatment: A review.}, journal = {Journal of environmental management}, volume = {247}, number = {}, pages = {849-866}, doi = {10.1016/j.jenvman.2019.06.053}, pmid = {31349180}, issn = {1095-8630}, mesh = {*Biofilms ; Bioreactors ; Nitrogen ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {The review encompasses the development of municipal wastewater treatment process using MBBR from early stages, established application, and recent advancements. An overview of main drivers leading to the MBBR technology development over its early stage is discussed. Biocarriers types and features together with biofilm development and role of extracellular polymeric substances (EPS) are presented, ultimately, addressing the challenge in decreasing startup time required for full operation. Furthermore, the review investigates the state of the art of MBBR technology for nutrient removal (i.e., COD and BOD, nitrogen and phosphorus) through process functionality and configuration of established (e.g., IFAS) and under development (e.g. PN/A) applications. Reactor operational characteristics such as filling fractions, mixing properties, dissolved oxygen requirements, and loading rates are presented and related to full scale examples. Current literature discussing the most recent studies on MBBR capability in reduction and removal of chemicals of emerging concern (CEC) released is presented. Ultimately, high rate carbon and nitrogen removal through A/B stage process are examined in its main operational parameters and its application towards energy neutrality suggesting novel MBBR application to further reduce energy requirements and plant footprint.}, } @article {pmid31347191, year = {2019}, author = {Kannan, S and Krishnamoorthy, G and Kulanthaiyesu, A and Marudhamuthu, M}, title = {Effect of biosurfactant derived from Vibrio natriegens MK3 against Vibrio harveyi biofilm and virulence.}, journal = {Journal of basic microbiology}, volume = {59}, number = {9}, pages = {936-949}, doi = {10.1002/jobm.201800706}, pmid = {31347191}, issn = {1521-4028}, support = {//Department of Biotechnology, Interdisciplinary Programme in Life Sciences/ ; //University Grants Commission (UGC-NFOBC)/ ; }, mesh = {Animals ; Aquaculture ; Artemia/microbiology ; Biofilms/*drug effects/growth & development ; Petroleum Pollution ; Quorum Sensing/drug effects ; Surface-Active Agents/isolation & purification/*pharmacology ; Vibrio/*chemistry/*drug effects/growth & development/pathogenicity ; Vibrio Infections/prevention & control/veterinary ; Virulence/*drug effects ; }, abstract = {Vibrio harveyi is a marine luminous pathogen, which causes biofilm-mediated infections, pressures the search for an innovative alternate approach to strive against vibriosis in aquaculture. This study anticipated to explore the effect of glycolipid biosurfactant as an antipathogenic against V. harveyi to control vibriosis. In this study, 27 bacterial strains were isolated from marine soil sediments. Out of these, 11 strains exhibited surfactant activity and the strain MK3 showed high emulsification index. The potent strain was identified as Vibrio natriegens and named as V. natriegens MK3. The extracted biosurfactant was purified using high-performance liquid chromatography and it was efficient to decrease the surface tension of the growth medium up to 21 mN/m. The functional group and composition of the biosurfactant were determined by Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy spectral studies and the nature of the biosurfactant was identified as glycolipid. The surfactant was capable of reducing the biofilm formation, bioluminescence, extracellular polysaccharide synthesis, and quorum sensing in marine shrimp pathogen V. harveyi. The antagonistic effect of biosurfactant was evaluated against V. harveyi-infected brine shrimp Artemia salina. This study reveals that biosurfactant can be considered for the management of biofilm-related aquatic infections.}, } @article {pmid31346374, year = {2019}, author = {Listiana-Kriswandini, I and Budi-Rahardjo, M and Soesilawati, P and Prisca-Suciadi, A}, title = {Detection of Candida albicans biofilm proteins induced by glucose, lactose, soy protein, and iron.}, journal = {Journal of clinical and experimental dentistry}, volume = {11}, number = {6}, pages = {e542-e546}, pmid = {31346374}, issn = {1989-5488}, abstract = {BACKGROUND: Oral candidiasis is one of the most common fungal infections, which attack the mucosa of the oral cavity. These lesions are mostly caused by the fungal species Candida albicans. Candida albicans is included in the normal oral microorganisms that are opportunistic pathogens, and its presence is quite large, which can reach 75% of the total oral fungal population. Research on specific proteins of Candida biofilm can be an alternative to early prevention of oral infections such as Oral Candidiasis. This biofilm protein can be used as a reference in making kits to detect the presence of microbes that cause infectious diseases. The purpose of this study was to determine molecular weight of Candida albicans biofilm protein induced by 5% glucose, 5% lactose, soy protein, and 5% iron.

MATERIAL AND METHODS: This experimental laboratory study used SDS-PAGE electrophoresis to determine the molecular weight of Candida albicans biofilm proteins induced by glucose 5%, lactose 5%, soy protein, and iron 5%.

RESULTS: Biofilm induced by 5% glucose shows four protein bands: 71,6 kDa; 56,1 kDa; 49,7 kDa; and 41 kDa. Biofilm induced by 5% lactose shows seven protein bands: 71 kDa; 61,2 kDa; 57,7 kDa; 55,3 kDa; 48,9 kDa; 39,5 kDa; and 29,8 kDa. Biofilm induced by soy protein shows one protein band: 49,4 kDa. Biofilm induced by 5% iron shows one protein band: 51,1 kDa.

CONCLUSIONS: Candida albicans biofilm induced by 5% glucose has four protein band candidates, 5% lactose has seven candidates of protein band, and soy protein and 5% iron each has a candidate of protein band, which can be used as a target for the detection of oral Candidiasis. Key words:Biofilm protein, Candida albicans, molecular weight, oral candidiasis.}, } @article {pmid31345229, year = {2019}, author = {Besser, M and Terberger, J and Weber, L and Ghebremedhin, B and Naumova, EA and Arnold, WH and Stuermer, EK}, title = {Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM).}, journal = {Journal of translational medicine}, volume = {17}, number = {1}, pages = {243}, pmid = {31345229}, issn = {1479-5876}, mesh = {*Biofilms ; Candida albicans ; Enterococcus faecium ; Humans ; Plasma/*microbiology ; Probiotics/*therapeutic use ; Pseudomonas aeruginosa ; Saccharomyces cerevisiae ; Staphylococcus aureus ; Translational Research, Biomedical ; Wound Healing ; }, abstract = {BACKGROUND: Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms.

METHODS: Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant.

RESULTS: SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum.

CONCLUSIONS: This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.}, } @article {pmid31344909, year = {2019}, author = {Zhang, T and Ying, D and Qi, M and Li, X and Fu, L and Sun, X and Wang, L and Zhou, Y}, title = {Anti-Biofilm Property of Bioactive Upconversion Nanocomposites Containing Chlorin e6 against Periodontal Pathogens.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {15}, pages = {}, pmid = {31344909}, issn = {1420-3049}, support = {81570983//National Natural Science Foundation of China/ ; 20180414030GH//International Cooperation Project of Science and Technology Development Jilin Province/ ; }, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Chlorophyllides ; Humans ; Hydrophobic and Hydrophilic Interactions ; Light ; Microbial Sensitivity Tests ; *Nanocomposites/chemistry ; Nanoparticles/chemistry ; Periodontitis/drug therapy/microbiology ; Photochemotherapy ; Photosensitizing Agents/chemistry/pharmacology ; Porphyrins/chemistry/*pharmacology ; Silanes/chemistry ; }, abstract = {Photodynamic therapy (PDT) based periodontal disease treatment has received extensive attention. However, the deep tissue location of periodontal plaque makes the conventional PDT encounter a bottleneck. Herein, upconversion fluorescent nanomaterial with near-infrared light excitation was introduced into the treatment of periodontal disease, overcoming the limited tissue penetration depth of visible light in PDT. Photosensitizer Ce6 molecules were combined with upconversion nanoparticles (UCNPs) NaYF4:Yb,Er with a novel strategy. The hydrophobic UCNPs were modified with amphiphilic silane, utilizing the hydrophobic chain of the silane to bind to the hydrophobic groups of the UCNPs through a hydrophobic-hydrophobic interaction, and the Ce6 molecules were loaded in this hydrophobic layer. This achieves both the conversion of the hydrophobic to the hydrophilic surface and the loading of the oily photosensitizer molecules. Because the excitation position of the Ce6 molecule is in the red region, Mn ions were doped to enhance red light, and thus the improved PDT function. This Ce6 loaded UCNPs composites with efficient red upconversion luminescence show remarkable bacteriological therapeutic effect on Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum and the corresponding biofilms under 980 nm irradiation, indicating a high application prospect in the treatment of periodontal diseases.}, } @article {pmid31344638, year = {2019}, author = {Jensen, MB and Strübing, D and de Jonge, N and Nielsen, JL and Ottosen, LDM and Koch, K and Kofoed, MVW}, title = {Stick or leave - Pushing methanogens to biofilm formation for ex situ biomethanation.}, journal = {Bioresource technology}, volume = {291}, number = {}, pages = {121784}, doi = {10.1016/j.biortech.2019.121784}, pmid = {31344638}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Bioreactors ; Euryarchaeota/*physiology ; Methane/*metabolism ; Plankton/metabolism ; }, abstract = {Biomethanation exploits the ability of methanogenic archaea to convert CO2 and renewable H2 from electrolysis to biomethane. Biofilm reactors are promising for biomethanation scale-up due to high CH4 productivity and low energy input for H2 gas-liquid mass transfer. Effects of operational conditions on biofilm dynamics remain largely uncharacterized but may increase reactor potentials further. This study investigated the effect of hydraulic retention time (HRT) on methanogenic biofilm activity and composition. Commercial carriers floating in liquid were exposed to H2/CO2 for 87 days with the liquid phase being subject to either 18 hours, 10 days, or 20 days HRT. Methanogenic biofilms were dominated by hydrogenotrophic methanogens, but biofilm CH4 productivity was enhanced at 18 hours HRT due to wash-out of competing planktonic species, which otherwise hampered proliferation of biofilm biomass at long HRT. It is suggested that high-rate biofilm reactors can increase methanogenic biofilm activity by minimizing the liquid's H2 exposure.}, } @article {pmid31344634, year = {2019}, author = {Song, T and Li, S and Jin, J and Yin, Z and Lu, Y and Bao, M and Li, Y}, title = {Enhanced hydrolyzed polyacrylamide removal from water by an aerobic biofilm reactor-ozone reactor-aerobic biofilm reactor hybrid treatment system: Performance, key enzymes and functional microorganisms.}, journal = {Bioresource technology}, volume = {291}, number = {}, pages = {121811}, doi = {10.1016/j.biortech.2019.121811}, pmid = {31344634}, issn = {1873-2976}, mesh = {Acrylic Resins ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; *Ozone ; Wastewater ; Water ; *Water Purification ; }, abstract = {Degradation of hydrolyzed polyacrylamide-containing (HPAM-containing) wastewater was investigated in a lab-scale aerobic-ozonic-aerobic hybrid treatment system. When the HPAM concentration was 500 mg L[-1] and the ozone dose was 25 g O3/g TOC, the HPAM removal rate reached 90.79%. Experimental results obtained from gel permeation chromatography (GPC) and rheometer indicated that the refractory HPAM was decomposed into small-molecule compounds. High performance liquid chromatography (HPLC) analysis showed that there was no acrylamide (AM) in the effluent of the system. Microbial communities in two aerobic biofilm reactors (ABRs) were analyzed by Illumina MiSeq Sequencing, which indicated that norank_f_Cytophagaceae, Meiothermus, Bacillus, etc. were keystone functional bacterial genera and Methanobacterium, norank_p_Bathyarchaeota, norank_c_Marine_Group_Ⅰ, etc. were dominant functional archaeal groups. To our knowledge, this is the first study to treat HPAM-containing wastewater using an aerobic-ozonic-aerobic hybrid process. Good removal efficiencies and presence of functional microorganisms demonstrated that the hybrid treatment system was practical for treating HPAM-containing wastewater.}, } @article {pmid31342619, year = {2019}, author = {Sivadon, P and Barnier, C and Urios, L and Grimaud, R}, title = {Biofilm formation as a microbial strategy to assimilate particulate substrates.}, journal = {Environmental microbiology reports}, volume = {11}, number = {6}, pages = {749-764}, doi = {10.1111/1758-2229.12785}, pmid = {31342619}, issn = {1758-2229}, support = {BIOLEO//Conseil Général des Pyrénées Atlantiques/International ; }, mesh = {Bacteria/growth & development/metabolism ; Bacterial Adhesion ; Biofilms/*growth & development ; Carbon/*metabolism ; *Microbial Consortia ; Organic Chemicals/*metabolism ; Particulate Matter/*metabolism ; }, abstract = {In most ecosystems, a large part of the organic carbon is not solubilized in the water phase. Rather, it occurs as particles made of aggregated hydrophobic and/or polymeric natural or man-made organic compounds. These particulate substrates are degraded by extracellular digestion/solubilization implemented by heterotrophic bacteria that form biofilms on them. Organic particle-degrading biofilms are widespread and have been observed in aquatic and terrestrial natural ecosystems, in polluted and man-driven environments and in the digestive tracts of animals. They have central ecological functions as they are major players in carbon recycling and pollution removal. The aim of this review is to highlight bacterial adhesion and biofilm formation as central mechanisms to exploit the nutritive potential of organic particles. It focuses on the mechanisms that allow access and assimilation of non-dissolved organic carbon, and considers the advantage provided by biofilms for gaining a net benefit from feeding on particulate substrates. Cooperative and competitive interactions taking place in biofilms feeding on particulate substrates are also discussed.}, } @article {pmid31341834, year = {2019}, author = {Gawish, S and Abbass, A and Abaza, A}, title = {Occurrence and biofilm forming ability of Pseudomonas aeruginosa in the water output of dental unit waterlines in a dental center in Alexandria, Egypt.}, journal = {Germs}, volume = {9}, number = {2}, pages = {71-80}, pmid = {31341834}, issn = {2248-2997}, abstract = {INTRODUCTION: Dental unit waterlines (DUWLs) are notorious for being contaminated with different bacterial species including the opportunistic pathogen Pseudomonas aeruginosa which poses a risk to patients and professionals. This work aimed at studying the occurrence and biofilm-forming ability (BFA) of P. aeruginosa in the output of DUWLs in a dental center in Egypt.

METHODS: Water samples were collected from the outlets of the high-speed hand piece, the air/water syringe and the cup filler waterlines. Bacteriological analysis included heterotrophic plate count (HPC), isolation and identification of P. aeruginosa and determination of the antimicrobial susceptibility and the BFA of the isolates by tissue culture plate (TCP) method and tube method (TM).

RESULTS: The average concentration of HPC bacteria in the output of the 3 DUWLs was 2.9×10[4] CFU/μL where 88.3% of the samples exceeded the Egyptian standards for drinking water (<50 CFU L). P. aeruginosa was isolated from nine cup filler samples (which had a water source different from the other waterlines). The isolates were sensitive to all tested antimicrobials. Of these nine isolates, 6, 5 and 4 were positive for BFA by TCP, modified TCP and TM, respectively.

CONCLUSIONS: More stringent measures are required to ensure safer dental water; as the majority of studied samples exceeded the required HPC bacterial limit and P. aeruginosa isolates were detected. P. aeruginosa isolates from DUWLs may not be as resistant to antibiotics as what is reported in the literature about clinical isolates. Some P. aeruginosa isolates can colonize DUWLs despite their inability to form biofilms in experimental testing.}, } @article {pmid31341833, year = {2019}, author = {Ahmed, DM and Messih, MAWA and Ibrahim, NH and Meabed, MH and Abdel-Salam, SM}, title = {Frequency of icaA and icaD determinants and biofilm formation among coagulase-negative staphylococci associated with nasal carriage in neonatal intensive care units.}, journal = {Germs}, volume = {9}, number = {2}, pages = {61-70}, pmid = {31341833}, issn = {2248-2997}, abstract = {INTRODUCTION: Nasal colonization with coagulase-negative staphylococci (CoNS) may be a preliminary risk factor for systemic infection. The aim of this study was to assess the frequency of ica A and D genes and biofilm formation among hospital-acquired nasal colonizing CoNS strains isolated from neonates in the neonatal intensive care units (NICUs). Antibiotic sensitivity patterns and some relevant risk factors were estimated.

METHODS: This study assessed nasal colonization with CoNS among neonates at days one and three of admission to NICUs of Beni-Suef University Hospital and Beni-Suef General Hospital from November 2015 to May 2016. The isolates were screened and identified; susceptibility testing was performed. Biofilm formation was examined using the Congo red agar method. Isolates identified as CoNS were tested by polymerase chain reaction (PCR) for the presence of mecA and icaA and icaD genes.

RESULTS: A total of 340 nasal swabs were collected from 170 neonates. The incidence of nasal colonization with CoNS was 50%. The species most frequently isolated were S. haemolyticus and S. epidermidis. Multidrug resistance (MDR) was detected in 86% of isolates. It was found that there was a strong association between the presence of mecA gene and phenotypic resistance to methicillin and also the presence of the icaA gene and biofilm formation.

CONCLUSIONS: Neonates admitted to NICUs can become reservoirs for CoNS strains, leading to potential dissemination of MDR strains into the community.}, } @article {pmid31340580, year = {2019}, author = {Bessa, LJ and Manickchand, JR and Eaton, P and Leite, JRSA and Brand, GD and Gameiro, P}, title = {Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections.}, journal = {International journal of molecular sciences}, volume = {20}, number = {14}, pages = {}, pmid = {31340580}, issn = {1422-0067}, support = {UID/QUI/50006/2019//FCT/MCTES through national funds/ ; 0193.000866/2015//FAP-DF/ ; }, mesh = {2-Naphthylamine/analogs & derivatives/chemistry ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Antimicrobial Cationic Peptides/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Culture Media/chemistry ; Humans ; Laurates/chemistry ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas aeruginosa/*drug effects/growth & development ; Staphylococcus aureus/*drug effects/growth & development ; }, abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.}, } @article {pmid31340472, year = {2019}, author = {Al-Bakri, AG and Mahmoud, NN}, title = {Photothermal-Induced Antibacterial Activity of Gold Nanorods Loaded into Polymeric Hydrogel against Pseudomonas aeruginosa Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {14}, pages = {}, pmid = {31340472}, issn = {1420-3049}, support = {1820-1104//the Deanship of Scientific Research at The University of Jordan/ ; 2017-2016/64/04//Deanship of Scientific Research and Graduate Studies at Al-Zaytoonah University of Jordan/ ; 3/2017//Abdul Hameed Shoman Foundation, Amman, Jordan/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development/radiation effects ; Colony Count, Microbial ; Gold/chemistry/*pharmacology ; Hydrogels/chemistry ; Low-Level Light Therapy/methods ; Microscopy, Electron, Transmission ; Nanotubes/*chemistry/ultrastructure ; Phosphatidylethanolamines/chemistry ; Plankton/*drug effects/growth & development/radiation effects ; Poloxamer/chemistry ; Pseudomonas aeruginosa/*drug effects/growth & development/radiation effects/ultrastructure ; }, abstract = {In this study, the photothermal-induced bactericidal activity of phospholipid-decorated gold nanorods (DSPE-AuNR) suspension against Pseudomonas aeruginosa planktonic and biofilm cultures was investigated. We found that the treatment of planktonic culture of Pseudomonas aeruginosa with DSPE-AuNR suspension (0.25-0.03 nM) followed by a continuous laser beam exposure resulted in ~6 log cycle reduction of the bacterial viable count in comparison to the control. The percentage reduction of Pseudomonas aeruginosa biofilm viable count was ~2.5-6.0 log cycle upon laser excitation with different concentrations of DSPE-AuNR as compared to the control. The photothermal ablation activity of DSPE-AuNR (0.125 nM) loaded into poloxamer 407 hydrogel against Pseudomonas aeruginosa biofilm resulted in ~4.5-5 log cycle reduction in the biofilm viable count compared to the control. Moreover, transmission electron microscope (TEM) images of the photothermally-treated bacteria revealed a significant change in the bacterial shape and lysis of the bacterial cell membrane in comparison to the untreated bacteria. Furthermore, the results revealed that continuous and pulse laser beam modes effected a comparable photothermal-induced bactericidal activity. Therefore, it can be concluded that phospholipid-coated gold nanorods present a promising nanoplatform to eradicate Pseudomonas aeruginosa biofilm responsible for common skin diseases.}, } @article {pmid31338728, year = {2020}, author = {Zaatout, N and Ayachi, A and Kecha, M}, title = {Epidemiological investigation of subclinical bovine mastitis in Algeria and molecular characterization of biofilm-forming Staphylococcus aureus.}, journal = {Tropical animal health and production}, volume = {52}, number = {1}, pages = {283-292}, pmid = {31338728}, issn = {1573-7438}, mesh = {Algeria ; Animals ; Asymptomatic Infections/epidemiology ; Biofilms ; Cattle ; Escherichia coli/isolation & purification ; Female ; Lactation ; Mastitis, Bovine/*epidemiology/microbiology ; Milk/microbiology ; Molecular Typing ; Prevalence ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus ; Staphylococcus aureus/*isolation & purification/physiology ; }, abstract = {Thirty dairy farms were selected for this study; the first objective of our study was to investigate the prevalence of subclinical bovine mastitis (SCM) in Eastern Algeria, from 600 lactating cows, and to identify potential risk factors associated with the occurrence of bovine mastitis and bacteria isolation using logistic regression. The second objective was to evaluate biofilm formation capacity and detect biofilm-associated genes of S. aureus, isolated from SCM cases. Molecular typing was investigated by spa typing. The prevalence of mastitis at cow and quarter level was 37.66% (226/600) and 27.17% (555/2042), respectively. Stage of lactation, cow breed, milk production, and the study area were factors associated with SCM. In addition, the most frequent pathogens isolated from mastitic milk were coagulase-negative staphylococci (CNS), E. coli, and S. aureus. The study area was highly associated with SCM caused by S. aureus; cows from Setif province were 18 times more affected with SCM caused by S. aureus compared to cows from Batna province (OR = 18.6, 95%CI 2.038-171.2), but were less affected with SCM caused by CNS isolates (OR = 0.17, 95%CI 0.033-0.868). Moreover, cows with milk production less than 10 L per day increased (p < 0.05) the prevalence of mastitis caused by E. coli. All the S. aureus isolates had biofilm-forming ability, and 41.66% of isolates were positive for adhesion genes (icaA, icaD, fbnA, and clfA). This study, therefore, warrants the need for improving sanitary measures and strict hygienic measures, and presents the first insight into biofilm-forming ability of S. aureus strains causing mastitis in dairy herds in Algeria, which will help in tracking the evolution of epidemic strains responsible for causing bovine mastitis.}, } @article {pmid31338076, year = {2019}, author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M}, title = {The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1499}, pmid = {31338076}, issn = {1664-302X}, abstract = {Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain to study heavy metal resistance and bioremediation as it is able to deal with high heavy metal concentrations. Biofilm formation by bacteria is mediated by the second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). The aim of this study was to characterize the response of C. metallidurans CH34 planktonic and biofilm cells to cadmium including their c-di-GMP regulatory pathway. Inhibition of the initiation of biofilm formation and EPS production by C. metallidurans CH34 correlates with increased concentration of cadmium. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium exposure to planktonic and biofilm cells induced the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium, the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase (PDE) involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated PDE. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 inhibits the initiation of biofilm lifestyle and involves a decrease in c-di-GMP levels and a novel metal regulated PDE.}, } @article {pmid31336660, year = {2019}, author = {Cadena, M and Kelman, T and Marco, ML and Pitesky, M}, title = {Understanding Antimicrobial Resistance (AMR) Profiles of Salmonella Biofilm and Planktonic Bacteria Challenged with Disinfectants Commonly Used During Poultry Processing.}, journal = {Foods (Basel, Switzerland)}, volume = {8}, number = {7}, pages = {}, pmid = {31336660}, issn = {2304-8158}, abstract = {Foodborne pathogens such as Salmonella that survive cleaning and disinfection during poultry processing are a public health concern because pathogens that survive disinfectants have greater potential to exhibit resistance to antibiotics and disinfectants after their initial disinfectant challenge. While the mechanisms conferring antimicrobial resistance (AMR) after exposure to disinfectants is complex, understanding the effects of disinfectants on Salmonella in both their planktonic and biofilm states is becoming increasingly important, as AMR and disinfectant tolerant bacteria are becoming more prevalent in the food chain. This review examines the modes of action of various types of disinfectants commonly used during poultry processing (quaternary ammonium, organic acids, chlorine, alkaline detergents) and the mechanisms that may confer tolerance to disinfectants and cross-protection to antibiotics. The goal of this review article is to characterize the AMR profiles of Salmonella in both their planktonic and biofilm state that have been challenged with hexadecylpyridinium chloride (HDP), peracetic acid (PAA), sodium hypochlorite (SHY) and trisodium phosphate (TSP) in order to understand the risk of these disinfectants inducing AMR in surviving bacteria that may enter the food chain.}, } @article {pmid31336253, year = {2019}, author = {Tian, Z and Liu, R and Zhang, H and Yang, M and Zhang, Y}, title = {Developmental dynamics of antibiotic resistome in aerobic biofilm microbiota treating wastewater under stepwise increasing tigecycline concentrations.}, journal = {Environment international}, volume = {131}, number = {}, pages = {105008}, doi = {10.1016/j.envint.2019.105008}, pmid = {31336253}, issn = {1873-6750}, mesh = {Aerobiosis ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Drug Resistance, Microbial ; Microbiota/*drug effects ; Tigecycline/*pharmacology ; Wastewater/*chemistry ; }, abstract = {This study aimed to investigate the impact of tigecycline, the third generation tetracycline, on the antibiotic resistance development in environmental microbiota. Two biological contact oxidation reactors containing aerobic biofilm microbiota were constructed, one of which was constantly fed with synthetic wastewater spiked with increasing concentrations of tigecycline (0 to 25 mg/L) under a hydrolytic retention time of 24 h. Over a period of 636 days, chemical oxygen demand removal over 90% and complete nitrification were achieved for both the control and tigecycline-exposed reactors, and effluent tigecycline concentrations in the tigecycline-exposed system were always <0.051 mg/L. Significant increases (p < 0.01) in resistome abundance and resistant bacteria ratio were detected at a tigecycline dose of 10 and 25 mg/L, respectively, revealed by metagenomic sequencing and culture-based method. The increase of resistome in the tigecycline system was mainly attributed to the enrichment of tetX, one cooperative tetracycline degrading gene. Partial canonical correspondence analysis showed that the change of resistome was mainly driven by bacterial community shift (vertical pathway). Network and genome binning analyses further suggested that the proliferation of Flavobacterium harboring tetX contributed to a relatively low community-wide resistance development in the aerobic biofilm microbiota under tigecycline selection by reducing the antibiotic concentration. This work provides scientific bases for the management and evaluation of the resistance risk induced by this novel antibiotic.}, } @article {pmid31336203, year = {2019}, author = {Chávez-Andrade, GM and Tanomaru-Filho, M and Basso Bernardi, MI and de Toledo Leonardo, R and Faria, G and Guerreiro-Tanomaru, JM}, title = {Antimicrobial and biofilm anti-adhesion activities of silver nanoparticles and farnesol against endodontic microorganisms for possible application in root canal treatment.}, journal = {Archives of oral biology}, volume = {107}, number = {}, pages = {104481}, doi = {10.1016/j.archoralbio.2019.104481}, pmid = {31336203}, issn = {1879-1506}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects ; Cattle ; Dental Pulp Cavity ; Enterococcus faecalis/drug effects ; Farnesol/*pharmacology ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects ; Root Canal Irrigants/*pharmacology ; Silver/*pharmacology ; }, abstract = {OBJECTIVE: This study aimed to evaluate the antimicrobial and biofilm anti-adhesion activities of poly(vinyl alcohol)-coated silver nanoparticles (AgNPs-PVA) and farnesol against Enterococcus faecalis, Candida albicans or Pseudomonas aeruginosa.

DESIGN: Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the solutions, as well as the effect on the biofilm biomass were evaluated. The biofilm anti-adhesion activity was evaluated using bovine root dentine treated with the solutions after 3 min of contact and analyzed by scanning electron microscopy (SEM) and by colony-forming units per milliliter (CFU mL[-1]) counting. Data were analyzed using ANOVA and Tukey's, the paired Student's t-test or Kruskal-Wallis and Dunn's tests (α = 0.05).

RESULTS: The MIC and MMC values (MIC/MMC) of the AgNPs-PVA and farnesol against E. faecalis were 42.5/50 μM and 0.85/1.0%, respectively. For C. albicans, the values were 27.5/37.5 μM and 1.75/2.5%; and for P. aeruginosa, 32.5/32.5 μM and 2.5/2.75%, respectively. Both solutions showed reduced biofilm biomass (p < 0.05). SEM analysis showed that dentine blocks treated with both solutions had lower biofilm formation than the control (saline), except for C. albicans. In the CFU mL[-1] counting, biofilm cells were viable in the all groups in comparison with control (p > 0.05).

CONCLUSIONS: AgNPs-PVA and farnesol showed antimicrobial and biofilm anti-adhesion activities, as well as potential for use as coadjuvant in endodontic treatment, and may be an option as auxiliary procedure for root canal disinfection or to inhibit biofilm formation.}, } @article {pmid31335442, year = {2019}, author = {Munro, APS and Highmore, CJ and Webb, JS and Faust, SN}, title = {Diagnosis and treatment of biofilm infections in children.}, journal = {Current opinion in infectious diseases}, volume = {32}, number = {5}, pages = {505-509}, doi = {10.1097/QCO.0000000000000582}, pmid = {31335442}, issn = {1473-6527}, support = {/DH_/Department of Health/United Kingdom ; }, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacterial Infections/*drug therapy/*surgery ; Biofilms/*growth & development ; Catheter-Related Infections/drug therapy ; Catheterization/adverse effects ; Child ; Child, Preschool ; Cystic Fibrosis/complications ; Humans ; Prostheses and Implants/adverse effects ; Prosthesis-Related Infections/drug therapy/surgery ; Surgical Procedures, Operative/*methods ; }, abstract = {PURPOSE OF REVIEW: Biofilm-associated infections cause difficulties in the management of childhood chronic infections and other diseases, due to the invasive nature of interventions which are often necessary for definitive management. Despite their importance, there are challenges in diagnosing biofilm infections and gaps in clinicians' understanding regarding the significance of biofilms.

RECENT FINDINGS: Many chronic infections associated with biofilms remain difficult or impossible to eradicate with conventional therapy. Surgical intervention, implant removal or long-term intermittent or suppressive antimicrobial therapy may be required. There are still significant challenges in detecting biofilms which presents a barrier in clinical practice and research. Novel therapies to disrupt biofilms are currently under investigation, which may help reduce the impact of antimicrobial resistance.

SUMMARY: Biofilm-associated infection should be considered wherever there is clinical concern for an infection affecting prosthetic material, where there is a predisposing condition such as suppurative lung disease; or in the setting of chronic or relapsing infections which may be culture negative. New diagnostic methods for detecting biofilms are a research priority for both clinical diagnosis and the ability to conduct high quality clinical trials of novel antibiofilm interventions.}, } @article {pmid31335187, year = {2019}, author = {Devivilla, S and Lekshmi, M and Kumar, SH and Valappil, RK and Roy, SD and Nayak, BB}, title = {Effect of Sodium Hypochlorite on Biofilm-Forming Ability of Histamine-Producing Bacteria Isolated from Fish.}, journal = {Journal of food protection}, volume = {82}, number = {8}, pages = {1417-1422}, doi = {10.4315/0362-028X.JFP-19-101}, pmid = {31335187}, issn = {1944-9097}, mesh = {Animals ; *Bacteria/drug effects ; *Biofilms/drug effects ; *Fishes/microbiology ; Histamine/metabolism ; *Sodium Hypochlorite/pharmacology ; }, abstract = {Histamine poisoning occurs when temperature-abused marine fish containing elevated levels of histamine are consumed. Histamine-producing bacteria found in fish can colonize processing surfaces and form biofilms. In this study, the biofilm-forming abilities of histamine-producing bacteria from Indian mackerel (Rastrelliger kanagurta) and the effect of hypochlorite treatment on biofilm formation were studied. The isolates of this study produced histamine in the range of 471 to 2,126 ppm. The histidine decarboxylase gene hdc was detected in all isolates producing histamine except in one strain each of Psychrobacter pulmonis and Proteus vulgaris. All isolates tested in this study produced moderate biofilms under control conditions, whereas exposure to 1 and 3 ppm of sodium hypochlorite significantly enhanced biofilm formation. However, exposure to 5 ppm of sodium hypochlorite showed an inhibitory effect on biofilm formation by all the isolates except Klebsiella variicola. The results of this study suggest that histamine-producing bacteria can form stable biofilms and that this activity may be enhanced by the application of low levels of sodium hypochlorite, a phenomenon that might influence the persistence of histamine-producing bacteria in fish processing areas.}, } @article {pmid31332872, year = {2020}, author = {Wang, Y and Du, Z and Liu, Y and Wang, H and Xu, F and Liu, B and Zheng, Z}, title = {The nitrogen removal and sludge reduction performance of a multi-stage anoxic/oxic (A/O) biofilm reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {92}, number = {1}, pages = {94-105}, doi = {10.1002/wer.1188}, pmid = {31332872}, issn = {1554-7531}, support = {ZR2016EEM32//Natural Science Foundation of Shandong Province/ ; 2015GSF117003//Shandong Province Key Development Projects/ ; SFSJKY2018-01//Scientific and Technological Innovation Project of Planning and Design Institute of Huaihe River Basin Water Conservancy Administration Bureau of Shandong Province in 2018/ ; 51878394//National Natural Science Foundation/ ; UDC2017031612//Science and Technology Plans of Ministry of Housing and Urban-Rural Development of the People's Republic of China, and Opening Projects of Beijing Advanced Innovation Center for Future Urban Design, Beijing University of Civil Engineering and Architecture/ ; }, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {To overcome the problems of high excess sludge yield and poor nitrogen removal efficiency in traditional biological treatment processes, a multi-stage A/O biofilm reactor was developed by combining the multi-stage A/O process with novel floating spherical carriers, resulting in repeated coupling of anoxic and aerobic environments. Results showed that the system achieved COD, NH 4 + - N , and TN removal efficiencies of 93.8%, 84.5%, and 75.7%, respectively, with average effluent concentrations lower than: 29.8 COD mg/L, 4.3 NH 4 + - N mg/L, and 13.2 TN mg/L. The observed sludge yield was 0.139 g MLSS/g COD, which was lower than that of the conventional activated sludge process. Microbial analysis showed that the community structure and cell morphology of microorganisms changed greatly with alternating aerobic-anoxic condition; high-throughput sequencing results proved that functional microorganisms can be enriched on the surface of the carries and therefore improved the nitrogen removal efficiency and meanwhile minimize the sludge yield within the system. PRACTITIONER POINTS: The research innovatively developed a novel floating spherical carrier and coupled it with multi-stage A/O process. The complex redox environments inside the floating spherical carriers improves the nitrogen removal efficiency and the sludge reduction effect. Nitrospirae, Hydrogenophaga promoted the nitrogen removal, Firmicutes, Bacteroidetes and Dechloromonas promoted the in-situ sludge reduction of the system.}, } @article {pmid31331112, year = {2019}, author = {Glasenapp, Y and Cattò, C and Villa, F and Saracchi, M and Cappitelli, F and Papenbrock, J}, title = {Promoting Beneficial and Inhibiting Undesirable Biofilm Formation with Mangrove Extracts.}, journal = {International journal of molecular sciences}, volume = {20}, number = {14}, pages = {}, pmid = {31331112}, issn = {1422-0067}, support = {57265315//MIUR-DAAD Joint Mobility Program/ ; }, mesh = {Acanthaceae/*chemistry ; Bacteria/drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Chromatography, Liquid ; Fungi/drug effects/growth & development ; Mass Spectrometry ; Metabolome ; Metabolomics/methods ; Plant Extracts/chemistry/*pharmacology ; Plant Leaves/chemistry ; Reactive Oxygen Species/metabolism ; }, abstract = {The extracts of two mangrove species, Bruguiera cylindrica and Laguncularia racemosa, have been analyzed at sub-lethal concentrations for their potential to modulate biofilm cycles (i.e., adhesion, maturation, and detachment) on a bacterium, yeast, and filamentous fungus. Methanolic leaf extracts were also characterized, and MS/MS analysis has been used to identify the major compounds. In this study, we showed the following. (i) Adhesion was reduced up to 85.4% in all the models except for E. coli, where adhesion was promoted up to 5.10-fold. (ii) Both the sum and ratio of extracellular polysaccharides and proteins in mature biofilm were increased up to 2.5-fold and 2.6-fold in comparison to the negative control, respectively. Additionally, a shift toward a major production of exopolysaccharides was found coupled with a major production of both intracellular and extracellular reactive oxygen species. (iii) Lastly, detachment was generally promoted. In general, the L. racemosa extract had a higher bioactivity at lower concentrations than the B. cylindrica extract. Overall, our data showed a reduction in cells/conidia adhesion under B. cylindrica and L. racemosa exposure, followed by an increase of exopolysaccharides during biofilm maturation and a variable effect on biofilm dispersal. In conclusion, extracts either inhibited or enhanced biofilm development, and this effect depended on both the microbial taxon and biofilm formation step.}, } @article {pmid31330991, year = {2019}, author = {Vitale, M and Galluzzo, P and Buffa, PG and Carlino, E and Spezia, O and Alduina, R}, title = {Comparison of Antibiotic Resistance Profile and Biofilm Production of Staphylococcus aureus Isolates Derived from Human Specimens and Animal-Derived Samples.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {3}, pages = {}, pmid = {31330991}, issn = {2079-6382}, support = {Fondo Finalizzato alla Ricerca//Università degli Studi di Palermo/ ; IZS SI 13/15 RC//Italian Ministry of Health/ ; IZS SI 08/16 RC//Italian Ministry of Health/ ; }, abstract = {BACKGROUND: The diffusion of antimicrobial resistance is a significant concern for public health worldwide. Staphylococcus aureus represents a paradigm microorganism for antibiotic resistance in that resistant strains appear within a decade after the introduction of new antibiotics.

METHODS: Fourteen S. aureus isolates from human specimens and twenty-one from samples of animal origin, were compared for their antimicrobial resistance and biofilm capability. In addition, they were characterized at the molecular level to detect the antimicrobial resistance mecA gene and genes related with enterotoxin, toxin, and biofilm production.

RESULTS: Both phenotypic and molecular analysis showed main differences among human- and animal-derived isolates. Among the human-derived isolates, more multidrug-resistant isolates were detected and mecA gene, enterotoxin, and toxin genes were more prevalent. Different genes involved in biofilm production were detected with bap present only in animal-derived isolates and sasC present in both isolates, however, with a higher prevalence in the human-derived isolates. Biofilm capability was higher in human-derived isolates mainly associated to the sasC gene.

CONCLUSIONS: The overall results indicate that human S. aureus isolates are more virulent and resistant than the isolates of animal origin randomly selected with no infection anamnesis. This study confirms that selection for more virulent and resistant S. aureus strains is related to the clinical practice.}, } @article {pmid31330825, year = {2019}, author = {Ly, S and Bajoul Kakahi, F and Mith, H and Phat, C and Fifani, B and Kenne, T and Fauconnier, ML and Delvigne, F}, title = {Engineering Synthetic Microbial Communities through a Selective Biofilm Cultivation Device for the Production of Fermented Beverages.}, journal = {Microorganisms}, volume = {7}, number = {7}, pages = {}, pmid = {31330825}, issn = {2076-2607}, abstract = {Production of Cambodian rice wine involves complex microbial consortia. Indeed, previous studies focused on traditional microbial starters used for this product revealed that three microbial strains with complementary metabolic activities are required for an effective fermentation, i.e., filamentous fungi (Rhizopus oryzae), yeast (Saccharomyces cerevisiae), and lactic acid bacteria (Lactobacillus plantarum). Modulating the ratio between these three key players led to significant differences, not only in terms of ethanol and organic acid production, but also on the profile of volatile compounds, in comparison with natural communities. However, we observed that using an equal ratio of spores/cells of the three microbial strains during inoculation led to flavor profile and ethanol yield close to that obtained through the use of natural communities. Compartmentalization of metabolic tasks through the use of a biofilm cultivation device allows further improvement of the whole fermentation process, notably by increasing the amount of key components of the aroma profile of the fermented beverage (i.e., mainly phenylethyl alcohol, isobutyl alcohol, isoamyl alcohol, and 2-methyl-butanol) and reducing the amount of off-flavor compounds. This study is a step forward in our understanding of interkingdom microbial interactions with strong application potential in food biotechnology.}, } @article {pmid31330262, year = {2019}, author = {Yu, M and Wang, X and Ling, F and Wang, H and Zhang, P and Shao, S}, title = {Atractylodes lancea volatile oils attenuated helicobacter pylori NCTC11637 growth and biofilm.}, journal = {Microbial pathogenesis}, volume = {135}, number = {}, pages = {103641}, doi = {10.1016/j.micpath.2019.103641}, pmid = {31330262}, issn = {1096-1208}, mesh = {Atractylodes/*chemistry ; Biofilms/*drug effects/growth & development ; Cell Line ; Drugs, Chinese Herbal/pharmacology ; Epithelial Cells ; Helicobacter pylori/*drug effects/*growth & development ; Inhibitory Concentration 50 ; Interleukin-8/metabolism ; Microbial Sensitivity Tests ; Oils, Volatile/*pharmacology ; Virulence Factors ; }, abstract = {Atractylodes lancea is a traditional Chinese perennial herb, which has been used for treating gastrointestinal diseases in traditional medicine. The aim of this study was to investigate the effect of Atractylodes lancea volatile oils on the planktonic growth and biofilm formation of Helicobacter pylori (H. pylori). Firstly, the minimal inhibitory concentration (MIC) of the volatile oils against H. pylori were determined using broth dilution method. SPSS17.0 was used to account 50% inhibiting concentration (IC50). Moreover, the anti-biofilm activity of the volatile oils was determined by crystal violet measurement and fluorescence microscope. Finally, gastric epithelial cells (GES-1 cells) were co-incubated with H. pylori with or without volatile oils treated. Real-time PCR and western blot were performed to detect the translocation of virulence factor Cag A. We found that Atractylodes lancea volatile oils inhibited the growth of H. pylori in a concentration dependent manner. The MIC and IC50 of volatile oils against H. pylori were 7.5 mg/mL and 2.181 mg/mL respectively. Fluorescence microscopy and crystal violet measurement indicated that volatile oils at sub-MIC concentration could reduce biofilm formation of H. pylori. In addition, volatile oils decreased the translocation of Cag A and reduced inflammatory cytokine IL-8 in GES-1 cells. Our results suggested that Atractylodes lancea volatile oils could be a potential compound of a novel class of H. pylori inhibitors with anti-H. pylori effects.}, } @article {pmid31329599, year = {2019}, author = {Lachica, MRCT and Anutrakunchai, C and Prajaneh, S and Nazmi, K and Bolscher, JGM and Taweechaisupapong, S}, title = {Synergistic effects of LFchimera and antibiotic against planktonic and biofilm form of Aggregatibacter actinomycetemcomitans.}, journal = {PloS one}, volume = {14}, number = {7}, pages = {e0217205}, pmid = {31329599}, issn = {1932-6203}, mesh = {Aggregatibacter actinomycetemcomitans/*physiology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/agonists/chemistry/genetics/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Humans ; Lactoferrin/agonists/chemistry/genetics/*pharmacology ; Periodontitis/drug therapy/microbiology ; Plankton/*growth & development ; Recombinant Fusion Proteins/chemistry/genetics/pharmacology ; }, abstract = {Adjunctive use of antibiotics in periodontal treatment have limitations and disadvantages including bacterial resistance. Antimicrobial peptides (AMPs) are potential new agents that can combat bacterial infection. In this study, antimicrobial activity of different concentrations of conventional antibiotics minocycline (MH), doxycycline (DOX), and antimicrobial peptides LL-37, LL-31, Lactoferrin chimera (LFchimera) and Innate Defense Regulator Peptide 1018 (IDR-1018) against Aggregatibacter actinomycetemcomitans ATCC 43718 were determined using colony culturing assay. Subsequently, in vitro activity of the most effective drug and peptide combination was evaluated by checkerboard technique. Impact of the drug and peptide co-administration on biofilm at different stages, i.e., during adhesion and 1-day old biofilm was compared to each of the agents used alone. Results revealed that the killing effects of all AMPs range from 13-100%. In contrast, MH and DOX at 1 and 5 μM showed no killing activity and instead stimulated growth of bacteria. DOX has better killing activity than MH. LFchimera displayed the strongest killing amongst the peptides. Checkerboard technique revealed that combining DOX and LFchimera yielded synergism. Confocal laser scanning microscopy further showed that the combination of DOX and LFchimera caused significant reduction of bacterial adhesion and reduction of biomass, average biofilm thickness and substratum biofilm coverage of 1-day old biofilm compared to DOX and LFchimera alone. In conclusion, LFchimera alone and in combination with DOX exhibited strong antibacterial and anti-biofilm property against A. actinomycetemcomitans. The findings suggest that LFchimera should be considered for development as a new potential therapeutic agent that may be used as an adjunctive treatment for periodontitis.}, } @article {pmid31329200, year = {2019}, author = {Kwon, HY and Kim, JY and Liu, X and Lee, JY and Yam, JKH and Dahl Hultqvist, L and Xu, W and Rybtke, M and Tolker-Nielsen, T and Heo, W and Kim, JJ and Kang, NY and Joo, T and Yang, L and Park, SJ and Givskov, M and Chang, YT}, title = {Visualizing biofilm by targeting eDNA with long wavelength probe CDr15.}, journal = {Biomaterials science}, volume = {7}, number = {9}, pages = {3594-3598}, doi = {10.1039/c9bm00152b}, pmid = {31329200}, issn = {2047-4849}, mesh = {*Biofilms ; DNA/*chemistry ; Extracellular Space/*chemistry ; Fluorescent Dyes/*chemistry ; Molecular Structure ; Pseudomonas aeruginosa/*chemistry ; }, abstract = {Detection of the biofilm of bacteria would be a counter strategy to detect hidden bacteria in their camouflage. Through unbiased screening of bacteria biofilm, we discovered a long wavelength probe CDr15 with extracellular DNA as the molecular target. CDr15 revealed a real-time geometric distribution of eDNA in a 3D bacterial colony.}, } @article {pmid31328358, year = {2019}, author = {Qiu, H and Pu, F and Liu, Z and Deng, Q and Sun, P and Ren, J and Qu, X}, title = {Depriving Bacterial Adhesion-Related Molecule to Inhibit Biofilm Formation Using CeO2 -Decorated Metal-Organic Frameworks.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {15}, number = {36}, pages = {e1902522}, doi = {10.1002/smll.201902522}, pmid = {31328358}, issn = {1613-6829}, mesh = {Adenosine Triphosphate/metabolism ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Cerium/*chemistry ; Metal-Organic Frameworks/*chemistry/pharmacology ; Reactive Oxygen Species/metabolism ; }, abstract = {The formation of bacterial biofilm is one of the causes of antimicrobial resistance, often leading to persistent infections and a high fatality rate. Therefore, there is an urgent need to develop novel and effective strategies to inhibit biofilm formation. Adenosine triphosphate (ATP) plays an important role in bacterial adhesion and biofilm formation through stimulating cell lysis and extracellular DNA (eDNA) release. Herein, a simple and robust strategy for inhibiting biofilm formation is developed using CeO2 -decorated porphyrin-based metal-organic frameworks (MOFs). The function of extracellular ATP (eATP) can be inhibited by CeO2 nanoparticles, leading to the disruption of the initial adhesion of bacteria. Furthermore, planktonic bacteria can be killed by cytotoxic reactive oxygen species (ROS) generated by MOFs. As a consequence, the synergic effect of eATP deprivation and ROS generation presents excellent capacity to prevent biofilm formation, which may provide a new direction for designing flexible and effective biofilm-inhibiting systems.}, } @article {pmid31328252, year = {2019}, author = {Bazzoli, A and Plateau, J and Turney, A}, title = {Improvement of microbial ecosystem in livestock animal environment: concept of positive biofilm using an example in swine farrowing.}, journal = {Australian veterinary journal}, volume = {97}, number = {9}, pages = {361}, doi = {10.1111/avj.12808}, pmid = {31328252}, issn = {1751-0813}, mesh = {*Animal Husbandry ; Animals ; *Biofilms ; *Drug Resistance, Bacterial ; Ecosystem ; Livestock/microbiology ; Swine/*microbiology ; }, } @article {pmid31326562, year = {2019}, author = {Sowndarya, J and Farisa Banu, S and Madhura, G and Yuvalakshmi, P and Rubini, D and Bandeira Junior, G and Baldisserotto, B and Vadivel, V and Nithyanand, P}, title = {Agro food by-products and essential oil constituents curtail virulence and biofilm of Vibrio harveyi.}, journal = {Microbial pathogenesis}, volume = {135}, number = {}, pages = {103633}, doi = {10.1016/j.micpath.2019.103633}, pmid = {31326562}, issn = {1096-1208}, mesh = {Acyclic Monoterpenes/isolation & purification/pharmacology ; Alginates/analysis ; Anti-Bacterial Agents/*pharmacology ; Aquaculture ; Biofilms/*drug effects ; Cell Survival/drug effects ; *Food ; Hydroxybenzoates/pharmacology ; Luteolin/isolation & purification/pharmacology ; Microbial Sensitivity Tests ; Oils, Volatile/*pharmacology ; Plant Extracts/*pharmacology ; Quorum Sensing/drug effects ; Vibrio/*drug effects/growth & development ; Vibrio Infections ; Virulence/*drug effects ; Virulence Factors ; }, abstract = {Vibrio harveyi causes severe loss to the aquaculture industry due to its virulence, which is mediated by Quorum sensing (QS) and biofilm formation. In the current study, we have explored the anti-virulent properties and biofilm disruption ability of luteolin (extracted from coconut shell) and linalool against this important aquaculture pathogen. HPLC analysis of the methanolic extract of coconut shells revealed a single major peak which matched to the standard luteolin which was further elucidated by NMR studies. Further, luteolin and linalool were screened for their ability to inhibit biofilms and various quorum sensing mediated virulence factors of V. harveyi. The Minimum Inhibitory Concentration (MIC) of the two compounds was determined and the sub-inhibitory concentrations of the compounds were able to inhibit biofilm formation. Both the compounds disrupted about 60-70% mature biofilms, which was also visually observed by light microscopy. Both linalool and luteolin exhibited a significant reduction in the production of EPS and alginate in the biofilms matrix of V. harveyi which was confirmed by Scanning Electron Microscopy (SEM). Both compounds inhibited the swarming and swimming motility, the crucial quorum sensing (QS) mediated virulence of V. harveyi. The present study shows the presence of valuable polyphenolic compound like luteolin in coconut shells that are discarded as a waste. From the present study we envisage that luteolin and linalool can serve as potent anti-virulent agents to combat QS mediated infections against aquaculture pathogens.}, } @article {pmid31325779, year = {2019}, author = {Borah, SN and Sen, S and Goswami, L and Bora, A and Pakshirajan, K and Deka, S}, title = {Rice based distillers dried grains with solubles as a low cost substrate for the production of a novel rhamnolipid biosurfactant having anti-biofilm activity against Candida tropicalis.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {182}, number = {}, pages = {110358}, doi = {10.1016/j.colsurfb.2019.110358}, pmid = {31325779}, issn = {1873-4367}, mesh = {Antifungal Agents/economics/isolation & purification/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida tropicalis/*drug effects/growth & development ; Drug Stability ; Factor Analysis, Statistical ; Fermentation ; Glycolipids/biosynthesis/economics/isolation & purification/*pharmacology ; Hot Temperature ; Hydrogen-Ion Concentration ; Micelles ; Microbial Sensitivity Tests ; Oryza/*chemistry/metabolism ; Pseudomonas aeruginosa ; Salinity ; Seeds/chemistry/metabolism ; Surface Tension ; Surface-Active Agents/economics/isolation & purification/metabolism/*pharmacology ; Water/chemistry ; }, abstract = {In this study, rhamnolipid (RL) production by Pseudomonas aeruginosa SS14 utilizing rice based Distillers Dried Grains with Solubles (rDDGS) as the sole carbon source was evaluated and the production parameters were optimized using response surface methodology. Highest RL (RL-rDDGS) yield was 14.87 g/L in a culture medium containing 12% (w/v) rDDGS and 11% (v/v) inoculum concentration after 48 h of fermentation at 35 °C. RL-rDDGS was produced as a mixture of mono and di-RL congeners with four novel homologues Rha-C18:2, Rha-C19, Rha-C9, and Rha-Rha-C19. The RL reduced the surface tension of water to 34.8 mN/m at a critical micelle concentration (CMC) value of 100 mg/L, exhibited high stability at a wide range of pH (6-12), heating time (0-120 min), and salinity (2-12% NaCl). Furthermore, RL-rDDGS demonstrated appreciable biofilm disruptive property against Candida tropicalis. This is the first report on the usage of rDDGS for sustainable and low cost production of RL.}, } @article {pmid31324055, year = {2019}, author = {Shi, Z and Dittoe, DK and Feye, KM and Kogut, M and Ricke, SC}, title = {Short Communication: Preliminary Differences Identified in Genes Responsible for Biofilm Formation in Poultry Isolates of Salmonella enterica Heidelberg, Enteritidis, and Kentucky.}, journal = {Microorganisms}, volume = {7}, number = {7}, pages = {}, pmid = {31324055}, issn = {2076-2607}, abstract = {Salmonella enterica is one of the most prevalent foodborne pathogens. The large quantity of serovar types results in the colonization of a large spectrum of hosts, with different environmental conditions and hazards. The aim of this study was to evaluate the differences in gene expression (bcsA and csgD) of Salmonella enterica serovars Heidelberg, Kentucky, and Enteritidis during biofilm formation using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Overall, there appeared to be differences in expression between the different serovars with high variation between strains. These data are important as they demonstrate considerable variability in gene expression between serovars and strains of poultry isolates of Salmonella enterica.}, } @article {pmid31323790, year = {2019}, author = {Carvalho, DB and Fox, EGP and Santos, DGD and Sousa, JS and Freire, DMG and Nogueira, FCS and Domont, GB and Castilho, LVA and Machado, EA}, title = {Fire Ant Venom Alkaloids Inhibit Biofilm Formation.}, journal = {Toxins}, volume = {11}, number = {7}, pages = {}, pmid = {31323790}, issn = {2072-6651}, mesh = {Alkaloids/*pharmacology ; Animals ; Ant Venoms/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Ants ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Polystyrenes ; Pseudomonas fluorescens/*drug effects/physiology ; Stainless Steel ; }, abstract = {Biofilm formation on exposed surfaces is a serious issue for the food industry and medical health facilities. There are many proposed strategies to delay, reduce, or even eliminate biofilm formation on surfaces. The present study focuses on the applicability of fire ant venom alkaloids (aka 'solenopsins', from Solenopsis invicta) tested on polystyrene and stainless steel surfaces relative to the adhesion and biofilm-formation by the bacterium Pseudomonas fluorescens. Conditioning with solenopsins demonstrates significant reduction of bacterial adhesion. Inhibition rates were 62.7% on polystyrene and 59.0% on stainless steel surfaces. In addition, solenopsins drastically reduced cell populations already growing on conditioned surfaces. Contrary to assumptions by previous authors, solenopsins tested negative for amphipathic properties, thus understanding the mechanisms behind the observed effects still relies on further investigation.}, } @article {pmid31323501, year = {2019}, author = {Morgan-Sagastume, F and Jacobsson, S and Olsson, LE and Carlsson, M and Gyllenhammar, M and Sárvári Horváth, I}, title = {Anaerobic treatment of oil-contaminated wastewater with methane production using anaerobic moving bed biofilm reactors.}, journal = {Water research}, volume = {163}, number = {}, pages = {114851}, doi = {10.1016/j.watres.2019.07.018}, pmid = {31323501}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Methane ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Oil-contaminated wastewaters are generally treated by a combination of physico-chemical and biological methods. Interest in the anaerobic treatment of oily wastewaters has increased since it complements aerobic treatment and produces energy in the form of methane. The objectives of this study were to characterise the anaerobic process spontaneously occurring in a full-scale storage tank at a facility treating waste oil and oil-contaminated effluents, and to evaluate the applicability of an anaerobic moving bed biofilm reactor (AnMBBR) and an anaerobic contact reactor (ACR) for treating the oil contaminated wastewater feeding the storage tank. Three lab-scale reactors were operated in parallel over 465 days: one mesophilic and one thermophilic AnMBBR, and one thermophilic ACR. The wastewater had a high strength with an average chemical oxygen demand (COD) of 36 g/L with a soluble fraction of 80%. The BOD7/COD ratios varied between 0.1 and 0.5, indicating low aerobic degradability. However, biomethane potential tests indicated some level of anaerobic degradability with methane yields between 150 and 200 NmL/gCOD. The full-scale storage tank operated at low organic loading rates (0.35-0.43 kgCOD/m[3]d), and long hydraulic retention times (HRT = 83-104 d). In comparison, the AnMBBRs achieved similar COD reductions (60%) as the full-scale tank but at a much shorter HRT of 30 d. Similar efficiency could only be reached at longer HRTs (43 d) in the ACR due to low biomass levels resulting from poor sludge settleability. The methane yield was higher (210 NmLCH4/COD removed) in the AnMBBR operated at 37 °C, compared to the other reactors working at 50 °C (180 NmLCH4/COD removed). This reactor also maintained a higher COD removal (67%) at an increased OLR of 1.1 kgCOD/m[3]d than the AnMBBR at 50 °C. The microbial composition of the biomass from the full-scale tank and the laboratory reactors provided evidence for the conversion of oil-contaminated wastewater into methane with a relatively high abundance of hydrogenotrophic methanogens.}, } @article {pmid31323469, year = {2019}, author = {Qi, X and Liu, P and Liang, P and Hao, W and Li, M and Huang, X}, title = {Dual-signal-biosensor based on luminescent bacteria biofilm for real-time online alert of Cu(II) shock.}, journal = {Biosensors & bioelectronics}, volume = {142}, number = {}, pages = {111500}, doi = {10.1016/j.bios.2019.111500}, pmid = {31323469}, issn = {1873-4235}, mesh = {Aliivibrio fischeri/drug effects/*physiology ; *Biofilms/drug effects ; Biosensing Techniques/*instrumentation/methods ; Copper/*analysis ; Electricity ; Electrodes ; Equipment Design ; Luminescence ; Water Pollutants, Chemical/*analysis ; }, abstract = {The development of real-time online warning system for toxicity materials is important to ensure the safety of water supply. This study for the first time constructs luminescent bacteria (Vibrio fischeri) biofilm to deliver both electrical and optical real-time response for Cu(II) toxic shock in a bioelectrochemical system (BES) sensor. Compared to biocathode, bioanode was more suitable as sensitive elements. With three tested concentrations of Cu(II), i.e., 1 mg/L, 3 mg/L and 6 mg/L, electrical signals were raised. But optical signal failed to respond to the lowest concentration, suggesting that electrical signal then was produced by chemical reaction of Cu(II) on the electrode surface. For 3 mg/L and 6 mg/L Cu(II) shock, more rapid optical signals were observed than electrical signal, indicating that both the biofilm's surface and inner was affected. In addition, high concentration of Cu(II) toxic as 6 mg/L caused irreversible damage in the biosensor as there were great fluctuation in the recovery curve and large recovery ratio up to -10.39% for optical signal. These results provided a comparison between optical and electrical signals simultaneously produced by a biosensor and visual evidences for better understanding of the toxicity process in the biosensor.}, } @article {pmid31323449, year = {2019}, author = {Li, D and Chen, S and Dou, H and Wu, W and Liu, Q and Zhang, L and Shen, Y and Shu, G and Yuan, Z and Lin, J and Zhang, W and Peng, G and Zhong, Z and Yin, L and Fu, H}, title = {Preparation of cefquinome sulfate cationic proliposome and evaluation of its efficacy on Staphylococcus aureus biofilm.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {182}, number = {}, pages = {110323}, doi = {10.1016/j.colsurfb.2019.06.053}, pmid = {31323449}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cations ; Cephalosporins/chemistry/pharmacology ; Cholesterol/chemistry ; Drug Compounding/*methods ; Drug Liberation ; Kinetics ; Liposomes/*chemistry ; Microbial Sensitivity Tests ; Phosphatidylcholines/chemistry ; Staphylococcus aureus/*drug effects/growth & development/ultrastructure ; }, abstract = {Staphylococcus aureus (S. aureus) has the propensity to form biofilms, which eventually cause antibiotic resistance and treatment failure. Cefquinome sulfate (CS) is an animal-specific antibacterial agent for S. aureus infection. In this work, CS cationic proliposomes (CSCPs) were prepared by solid-dispersion method combined with effervescent hydration to eradicate bacterial biofilm and improve the antibacterial effect of the drug. CSCPs were readily dispersed in water, thereby forming CS cationic liposomes (CSCLs) as a white, uniform suspension. The CSCLs had an encapsulation efficiency (EE) of 63.21%, a drug loading of 4.04%, an average particle size of 201.5 nm, and a positive zeta-potential of 65.29 mV. In vitro release studies showed that CSCLs had good sustained-release behavior. The CS and CSCL minimal inhibitory concentration (MIC) of S. aureus type culture strain were 1 and 0.48 g/mL, respectively. The eradication effect of CS on bacterial biofilm (BBF) was relatively weak during culture in drug-containing medium for 8 h-24 h. However, the CSCL eradication effect on BBF increased gradually, and the clearance rate of CSCLs on BBF was about twice that of CS. The clearance rate reached 81.30% with 2.5 × MIC in 24 h. All these results indicated that CSCLs can significantly improve the eradication effect of cefquinome on biofilm to inhibit bacterial growth.}, } @article {pmid31323072, year = {2019}, author = {, }, title = {Correction: Circuit diversification in a biofilm regulatory network.}, journal = {PLoS pathogens}, volume = {15}, number = {7}, pages = {e1007966}, pmid = {31323072}, issn = {1553-7374}, abstract = {[This corrects the article DOI: 10.1371/journal.ppat.1007787.].}, } @article {pmid31321751, year = {2019}, author = {Černáková, L and Light, C and Salehi, B and Rogel-Castillo, C and Victoriano, M and Martorell, M and Sharifi-Rad, J and Martins, N and Rodrigues, CF}, title = {Novel Therapies for Biofilm-Based Candida spp. Infections.}, journal = {Advances in experimental medicine and biology}, volume = {1214}, number = {}, pages = {93-123}, doi = {10.1007/5584_2019_400}, pmid = {31321751}, issn = {0065-2598}, mesh = {Antifungal Agents/therapeutic use ; *Biofilms/drug effects ; Candida/drug effects ; *Candidiasis/drug therapy/therapy ; Drug Resistance, Fungal ; Humans ; Microbial Sensitivity Tests ; Photochemotherapy ; }, abstract = {The presence of fungal infections continue to grow worldwide, mostly in immunosuppressed patients, and in individuals with continued antimicrobial treatments. Candida spp. are the most common yeasts involved in these disorders, being associated with a high rate of antifungal resistance and an increased ability to form biofilms, which make the treatment of these infections difficult. This review aims to present and discuss the main biofilm-related infections cause by several Candida spp. and novel therapies that are currently available in the clinical, scientific and academic environment. New drugs with promising antifungal activity, natural approaches (e.g. probiotics, essential oils, plant extracts, honey) and a final consideration on alternative methodologies, such as photodynamic therapy are presented and discussed.}, } @article {pmid31321337, year = {2019}, author = {Pakshir, K and Sheykhi, S and Zomorodian, K and Nouraei, H and Zare Shahrabadi, Z}, title = {Evaluation of biofilm formation in the homozygous and heterozygous strains of vaginal Candida albicans isolates.}, journal = {Current medical mycology}, volume = {5}, number = {2}, pages = {37-40}, pmid = {31321337}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: Candida albicans is one of the most opportunistic yeasts around the world. This species has two heterozygous and homozygous strains at hyphal wall protein 1 (hwp1) gene locus. A simple method for the discrimination of these two strains is the amplification of HWP1 gene. Regarding this, the aim of this study was to discriminate C. albicans heterozygous and homozygous strains via the amplification of hwp1 gene and evaluation of biofilm formation between the strains.

MATERIALS AND METHODS: A total of 60 homozygous (n=30) and heterozygous (n=30) strains were discriminated among 126 C. albicans vaginal isolates by the amplification of HWP1 gene, using specific primers. The evaluation of biofilm formation was accomplished using the visual method.

RESULTS: According to the results, the homozygous and heterozygous strains produced one and two DNA fragments, respectively. The frequency of homozygous strains among the C. albicans vaginal isolates was 76.2%. Biofilm formation activity in the heterozygous strains was more than that in the homozygous strains. However, statistical analysis showed no significant difference between the strains in terms of biofilm formation.

CONCLUSION: As the findings indicated, the frequency of the heterozygous strains in C. albicans was lower than that of the homozygous strains. Both of the strains could form biofilm in the different ranges of severity. High activity of biofilm formation in heterozygous strains may set the ground for its pathogenicity.}, } @article {pmid31320183, year = {2019}, author = {Lee, MJ and Kwon, JS and Kim, JY and Ryu, JH and Seo, JY and Jang, S and Kim, KM and Hwang, CJ and Choi, SH}, title = {Bioactive resin-based composite with surface pre-reacted glass-ionomer filler and zwitterionic material to prevent the formation of multi-species biofilm.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {9}, pages = {1331-1341}, doi = {10.1016/j.dental.2019.06.004}, pmid = {31320183}, issn = {1879-0097}, mesh = {Adsorption ; Bacterial Adhesion ; *Biofilms ; Composite Resins ; Dental Materials ; Humans ; *Streptococcus mutans ; }, abstract = {OBJECTIVE: This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).

METHODS: MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.

RESULTS: Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P<0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P<0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P<0.01).

SIGNIFICANCE: Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.}, } @article {pmid31319827, year = {2019}, author = {Ahmed, AA and Salih, FA}, title = {Quercus infectoria gall extracts reduce quorum sensing-controlled virulence factors production and biofilm formation in Pseudomonas aeruginosa recovered from burn wounds.}, journal = {BMC complementary and alternative medicine}, volume = {19}, number = {1}, pages = {177}, pmid = {31319827}, issn = {1472-6882}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects ; Plant Extracts/*pharmacology ; Plant Tumors ; Pseudomonas aeruginosa/*drug effects/genetics/*physiology ; Quercus/*chemistry ; Quorum Sensing/*drug effects ; Virulence Factors/genetics/*metabolism ; }, abstract = {BACKGROUND: Quercus gall extracts' ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies. The current investigation is focused on the action of extracts of Quercus infectoria gall in their sub-inhibitory concentrations on the corresponding bacterial behaviours instead of killing them.

METHODS: The effect of gall extracts on the quorum sensing (QS) associated virulence of multiple drug resistant Pseudomonas aeruginosa recovered from burns wounds was studied. The influence of different extracts on the production of bacterial virulence and biofilm, and expression of the genes encoding quorum sensing and exotoxin A were investigated. Quorum sensing is a crucial regulator of virulence and biofilm development in Pseudomonas aeruginosa and other medical related microbes.

RESULTS: Experiments to characterise and quantify Q. infectoria gall extracts impact on the quorum sensing networks of P.aeruginosa revealed that the expression of las, rhl, and exotoxin A (ETA) genes levels including the associated virulence were reduced by the extracts at their subinhibitory concentrations.

CONCLUSIONS: The obtained results indicated that extracts of Q. infectoria galls fight infections either by their inhibitory constituents, which vigorously eradicate cells or by disruption of the pathogens quorum sensing system through weakening the virulence and bacterial coordination.}, } @article {pmid31319670, year = {2019}, author = {Balasubramanian, S and Aubin-Tam, ME and Meyer, AS}, title = {3D Printing for the Fabrication of Biofilm-Based Functional Living Materials.}, journal = {ACS synthetic biology}, volume = {8}, number = {7}, pages = {1564-1567}, doi = {10.1021/acssynbio.9b00192}, pmid = {31319670}, issn = {2161-5063}, mesh = {Alginates/chemistry ; Biodegradation, Environmental ; Biofilms/*growth & development ; Bioprinting/*methods ; Escherichia coli/*cytology/physiology ; Extracellular Matrix/physiology ; Hydrogels/chemistry ; Printing, Three-Dimensional ; Synthetic Biology/methods ; }, abstract = {Bacterial biofilms are three-dimensional networks of cells entangled in a self-generated extracellular polymeric matrix composed of proteins, lipids, polysaccharides, and nucleic acids. Biofilms can establish themselves on virtually any accessible surface and lead to varying impacts ranging from infectious diseases to degradation of toxic chemicals. Biofilms exhibit high mechanical stiffness and are inherently tolerant to adverse conditions including the presence of antibiotics, pollutants, detergents, high temperature, changes in pH, etc. These features make biofilms resilient, which is beneficial for applications in dynamic environments such as bioleaching, bioremediation, materials production, and wastewater purification. We have recently described an easy and cost-effective method for 3D printing of bacteria and have extended this technology for 3D printing of genetically engineered Escherichia coli biofilms. Our 3D printing platform exploits simple alginate chemistry for printing of a bacteria-alginate bioink mixture onto calcium-containing agar surfaces, resulting in the formation of bacteria-encapsulating hydrogels with varying geometries. Bacteria in these hydrogels remain intact, spatially patterned, and viable for several days. Printing of engineered bacteria to produce inducible biofilms leads to formation of multilayered three-dimensional structures that can tolerate harsh chemical treatments. Synthetic biology and material science approaches provide the opportunity to append a wide range of useful functionalities to these 3D-printed biofilms. In this article, we describe the wide range of future applications possible for applying functional 3D-printed biofilms to the construction of living biofilm-derived materials in a large-scale and environmentally stable manner.}, } @article {pmid31319057, year = {2019}, author = {Narayana, JL and Mishra, B and Lushnikova, T and Golla, RM and Wang, G}, title = {Modulation of antimicrobial potency of human cathelicidin peptides against the ESKAPE pathogens and in vivo efficacy in a murine catheter-associated biofilm model.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1861}, number = {9}, pages = {1592-1602}, pmid = {31319057}, issn = {1879-2642}, support = {R01 AI105147/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Animals ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Antimicrobial Cationic Peptides/metabolism/*pharmacology ; Biofilms/*drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Mice ; Microbial Sensitivity Tests ; Protein Engineering/methods ; Staphylococcus aureus/drug effects ; Cathelicidins ; }, abstract = {Antimicrobial peptides are essential components of innate immune systems that protect hosts from infection. They are also useful candidates for developing a new generation of antibiotics to fight antibiotic-resistant pathogens. Human innate immune peptide LL-37 can inhibit biofilm formation, but suffers from high cost due to a long peptide length and rapid protease degradation. To improve the peptide, we previously identified the major active region and changed the peptide backbone structure. This study designed two families of new peptides by altering peptide side chains. Interestingly, these peptides displayed differential potency against various ESKAPE pathogens in vitro and substantially reduced hemolysis. Further potency test in vivo revealed that 17tF-W eliminated the burden of methicillin-resistant Staphylococcus aureus (MRSA) USA300 in both mouse-embedded catheters and their surrounding tissues. In addition, peptide treatment suppressed the level of chemokine TNFα, and boosted the levels of chemokines MCP-1, IL-17A and IL-10 in the surrounding tissues of the infected catheter embedded in mice. In conclusion, we have designed a set of new LL-37 peptides with varying antimicrobial activities, opening the door to potential topical treatment of infections involving different drug-resistant pathogens.}, } @article {pmid31318574, year = {2019}, author = {Patel, KK and Surekha, DB and Tripathi, M and Anjum, MM and Muthu, MS and Tilak, R and Agrawal, AK and Singh, S}, title = {Antibiofilm Potential of Silver Sulfadiazine-Loaded Nanoparticle Formulations: A Study on the Effect of DNase-I on Microbial Biofilm and Wound Healing Activity.}, journal = {Molecular pharmaceutics}, volume = {16}, number = {9}, pages = {3916-3925}, doi = {10.1021/acs.molpharmaceut.9b00527}, pmid = {31318574}, issn = {1543-8392}, mesh = {Animals ; Biofilms/*drug effects ; Cell Survival/drug effects ; Cells, Cultured ; Chitosan/chemistry ; Deoxyribonuclease I/chemistry/*pharmacology ; Drug Compounding/methods ; Drug Delivery Systems/*methods ; Excipients/chemistry ; Fibroblasts/metabolism ; Humans ; Male ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*physiology ; Rats ; Rats, Wistar ; Silver Sulfadiazine/chemistry/*pharmacology ; Skin/cytology ; Treatment Outcome ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {Biofilm resistance is one of the severe complications associated with chronic wound infections, which impose extreme microbial tolerance against antibiotic therapy. Interestingly, deoxyribonuclease-I (DNase-I) has been empirically proved to be efficacious in improving the antibiotic susceptibility against biofilm-associated infections. DNase-I hydrolyzes the extracellular DNA, a key component of the biofilm responsible for the cell adhesion and strength. Moreover, silver sulfadiazine, a frontline therapy in burn wound infections, exhibits delayed wound healing due to fibroblast toxicity. In this study, a chitosan gel loaded with solid lipid nanoparticles of silver sulfadiazine (SSD-SLNs) and supplemented with DNase-I has been developed to reduce the fibroblast cytotoxicity and overcome the biofilm-imposed resistance. The extensive optimization using the Box-Behnken design (BBD) resulted in the formation of SSD-SLNs with a smooth surface as confirmed by scanning electron microscopy and controlled release (83%) for up to 24 h. The compatibility between the SSD and other formulation excipients was confirmed by Fourier transform infrared, differential scanning calorimetry, and powder X-ray diffraction studies. Developed SSD-SLNs in combination with DNase-I inhibited around 96.8% of biofilm of Pseudomonas aeruginosa as compared to SSD with DNase-I (82.9%). In line with our hypothesis, SSD-SLNs were found to be less toxic (cell viability 90.3 ± 3.8% at 100 μg/mL) in comparison with SSD (Cell viability 76.9 ± 4.2%) against human dermal fibroblast cell line. Eventually, the results of the in vivo wound healing study showed complete wound healing after 21 days' treatment with SSD-SLNs along with DNase-I, whereas marketed formulations SSD and SSD-LSNs showed incomplete healing after 21 days. Data in hand suggest that the combination of SSD-SLNs with DNase-I is an effective treatment strategy against the biofilm-associated wound infections and accelerates wound healing.}, } @article {pmid31318043, year = {2019}, author = {Alsahhaf, A and Al-Aali, KA and Alshagroud, RS and Alshiddi, IF and Alrahlah, A and Abduljabbar, T and Javed, F and Vohra, F}, title = {Comparison of yeast species in the subgingival oral biofilm of individuals with type 2 diabetes and peri-implantitis and individuals with peri-implantitis without diabetes.}, journal = {Journal of periodontology}, volume = {90}, number = {12}, pages = {1383-1389}, doi = {10.1002/JPER.19-0091}, pmid = {31318043}, issn = {1943-3670}, support = {//Deanship of Scientific Research, King Saud University/International ; }, mesh = {*Alveolar Bone Loss ; Biofilms ; *Dental Implants ; *Diabetes Mellitus, Type 2 ; Humans ; Middle Aged ; *Peri-Implantitis ; Periodontal Index ; Phylogeny ; }, abstract = {BACKGROUND: There are no studies that have investigated the presence of yeasts in the subgingival oral biofilm (OB) of type-2 diabetic and non-diabetic patients with peri-implantitis. The aim was to assess the presence of yeasts in the subgingival OB of patients with type 2 diabetes and peri-implantitis and patients with peri-implantitis without diabetes.

METHODS: Patients with type 2 diabetes with peri-implantitis (group A), non-diabetic individuals with peri-implantitis and without diabetes (group B), and individuals with and without peri-implantitis (group C) were included. Lifestyle-related and demographic data were collected using a questionnaire and hemoglobin A1c levels were measured. Peri-implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were evaluated and crestal bone loss (CBL) were measured. Subgingival OB samples were collected and oral yeasts species were identified using ChromAgar medium. Level of significance was set at P <0.05.

RESULTS: The mean age of individuals in groups A (n = 43), B (n = 41), and C (n = 42) were 55.6 ± 6.4, 54.6 ± 4.5, and 57.1 ± 3.3 years, respectively. The mean HbA1c levels were higher in group A (P <0.01) than groups B and C. Peri-implant PI (P <0.01), BOP (P <0.01), PD (P <0.01), and CBL (P <0.01) were significantly higher in group A compared with patients in groups B and C. Peri-implant PI (P <0.05), BOP (P <0.05), PD (P <0.05), and CBL (P <0.05) were significantly higher among patients in group B compared with group C. Subgingival yeasts were more often isolated from the OB of patients in groups A (74.4%) and B (46.3%) than group C (7.1%). The most common yeast species identified in all groups was Candida albicans. The CFU/mL for subgingival yeasts were higher in group A than groups B (P <0.01) and C (P <0.01). The CFU/mL for subgingival yeasts were higher in group B than group C (P <0.01).

CONCLUSION: Candida species (predominantly C. albicans) were more often present in the subgingival OB of patients with and without type 2 diabetes with peri-implantitis than systemically healthy individuals without peri-implant diseases.}, } @article {pmid31315967, year = {2019}, author = {Sherman, E and Bayles, K and Moormeier, D and Endres, J and Wei, T}, title = {Observations of Shear Stress Effects on Staphylococcus aureus Biofilm Formation.}, journal = {mSphere}, volume = {4}, number = {4}, pages = {}, pmid = {31315967}, issn = {2379-5042}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Image Processing, Computer-Assisted/methods ; *Shear Strength ; Staphylococcus aureus/*physiology ; *Stress, Physiological ; }, abstract = {Staphylococcus aureus bacteria form biofilms and distinctive microcolony or "tower" structures that facilitate their ability to tolerate antibiotic treatment and to spread within the human body. The formation of microcolonies, which break off, get carried downstream, and serve to initiate biofilms in other parts of the body, is of particular interest here. It is known that flow conditions play a role in the development, dispersion, and propagation of biofilms in general. The influence of flow on microcolony formation and, ultimately, what factors lead to microcolony development are, however, not well understood. The hypothesis being examined is that microcolony structures form within a specific range of levels of shear stress. In this study, laminar shear flow over a range of 0.15 to 1.5 dynes/cm[2] was examined. It was found that microcolony structures form in a narrow range of shear stresses around 0.6 dynes/cm[2] Further, measurements of cell density as a function of space and time showed that shear dependence can be observed hours before microcolonies form. This is significant because, among other physiologic flows, this is the same shear stress found in large veins in the human vasculature, which, along with catheters of similar diameters and flow rates, may therefore play a critical role in biofilm development and subsequent spreading of infections throughout the body.IMPORTANCE It is well known that flow plays an important role in the formation, transportation, and dispersion of Staphylococcus aureus biofilms. What was heretofore not known was that the formation of tower structures in these biofilms is strongly shear stress dependent; there is, in fact, a narrow range of shear stresses in which the phenomenon occurs. This work quantifies the observed shear dependence in terms of cell growth, distribution, and fluid mechanics. It represents an important first step in opening up a line of questioning as to the interaction of fluid forces and their influence on the dynamics of tower formation, break-off, and transportation in biofilms by identifying the parameter space in which this phenomenon occurs. We have also introduced state-of-the-art flow measurement techniques to address this problem.}, } @article {pmid31315572, year = {2019}, author = {Zeighami, H and Valadkhani, F and Shapouri, R and Samadi, E and Haghi, F}, title = {Virulence characteristics of multidrug resistant biofilm forming Acinetobacter baumannii isolated from intensive care unit patients.}, journal = {BMC infectious diseases}, volume = {19}, number = {1}, pages = {629}, pmid = {31315572}, issn = {1471-2334}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification/*pathogenicity ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Cross Infection/microbiology ; Drug Resistance, Multiple, Bacterial/drug effects/*genetics ; Humans ; Immunocompromised Host ; Intensive Care Units ; Iran ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Virulence ; }, abstract = {BACKGROUND: Nosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide.

METHODS: A total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR.

RESULTS: All isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness.

CONCLUSION: Our study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.}, } @article {pmid31314663, year = {2019}, author = {Sianglum, W and Muangngam, K and Joycharat, N and Voravuthikunchai, SP}, title = {Mechanism of Action and Biofilm Inhibitory Activity of Lupinifolin Against Multidrug-Resistant Enterococcal Clinical Isolates.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {10}, pages = {1391-1400}, doi = {10.1089/mdr.2018.0391}, pmid = {31314663}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/drug effects ; Drug Resistance, Multiple, Bacterial ; Enterococcus faecalis/*drug effects/isolation & purification ; Enterococcus faecium/*drug effects/isolation & purification ; Flavonoids/administration & dosage/*pharmacology ; Gram-Positive Bacterial Infections/epidemiology/microbiology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {The treatment of enterococcal infections is becoming more difficult because of multidrug resistance (MDR). Lupinifolin, a prenylated flavonoid isolated from Albizia myriophylla Benth., showed a potent antimicrobial activity against enterococci. The aim of this study was to investigate antibacterial activity and action of lupinifolin against MDR enterococcal clinical isolates. Antibacterial properties of lupinifolin against 21 MDR isolates were assessed using broth microdilution method and time-kill assay. To study mode of action of lupinifolin on the isolates, propidium iodide intensity, salt tolerance assay, and electron microscopic analyses were performed. Antibiofilm formation activity of lupinifolin was conducted using crytal violet assay. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration values of lupinifolin against the isolates ranged between 0.5 and 2.0 μg/mL and between 2 and 16 μg/mL, respectively. Lupinifolin at 2MIC and 4MIC inhibited the bacterial growth >2 log colony-forming units (CFU)/mL at 2 hr incubation by time-kill analysis. The compound increased membrane permeability and caused loss of salt tolerance. SEM and TEM micrographs revealed pronounced morphological and ultrastructural changes in the treated bacteria. Crystal violet staining showed the antibiofilm-producing activity of lupinifolin against four MDR enterococci. This study suggested that lupinifolin is an essential antimicrobial agent that could be useful for the treatment of MDR enterococcal infections.}, } @article {pmid31313963, year = {2019}, author = {Khelissa, SO and Abdallah, M and Jama, C and Barras, A and Chihib, NE}, title = {Comparative Study on the Impact of Growth Conditions on the Physiology and the Virulence of Pseudomonas aeruginosa Biofilm and Planktonic Cells.}, journal = {Journal of food protection}, volume = {82}, number = {8}, pages = {1357-1363}, doi = {10.4315/0362-028X.JFP-18-565}, pmid = {31313963}, issn = {1944-9097}, mesh = {*Biofilms ; HeLa Cells ; Humans ; *Plankton/microbiology ; Polycarboxylate Cement ; *Pseudomonas aeruginosa/growth & development/pathogenicity ; Stainless Steel ; Temperature ; Virulence Factors/metabolism ; }, abstract = {The aim of the present work was to study and compare the effect of growth temperature (20, 30, and 37°C) and surface type (stainless steel and polycarbonate) on the production of virulence factors, such as proteases and siderophores, and the risk of surface contamination associated with Pseudomonas aeruginosa biofilm and planktonic cells. The increase of growth temperature from 20 to 37°C increased (approximately twofold) the electronegative charge and the hydrophobicity of the P. aeruginosa biofilm cell surface. P. aeruginosa biofilm cell adhesion to stainless steel and polycarbonate was 5- and 1.5-fold higher than their planktonic counterparts at 20 and 30°C, respectively. The increase of growth temperature from 20 to 37°C increased the production of proteases (twofold) and siderophores (twofold) and the cytotoxicity (up to 30-fold) against the HeLa cell line in the supernatants of P. aeruginosa planktonic and biofilm cultures. This study also highlighted that biofilm and planktonic P. aeruginosa cells exhibited distinct physiological properties with respect to the production of virulence factors and the cytotoxicity against the Hela cell line. Therefore, effective disinfection procedures should be adapted to inactivate bacteria detached from biofilms.}, } @article {pmid31312343, year = {2019}, author = {Wei, Q and Zhang, Z and Luo, J and Kong, J and Ding, Y and Chen, Y and Wang, K}, title = {Insulin treatment enhances pseudomonas aeruginosa biofilm formation by increasing intracellular cyclic di-GMP levels, leading to chronic wound infection and delayed wound healing.}, journal = {American journal of translational research}, volume = {11}, number = {6}, pages = {3261-3279}, pmid = {31312343}, issn = {1943-8141}, abstract = {Diabetes-related infections have become challenging and important public health problems in China and around the world. P. aeruginosa plays an important role in diabetic foot infections. As a gram-negative opportunistic pathogen, P. aeruginosa causes recurrent and refractory infections that are characterized by biofilm formation. Previous studies have demonstrated that biofilm-challenged wounds typically take longer to heal than non-biofilm-challenged normal wounds in diabetic mouse models. In the present study, we sought to explore the mechanism via which insulin treatment affects cyclic di-GMP signaling in P. aeruginosa-infected chronic wounds in db/db diabetic mice. We found that the wounds of diabetic mice healed more slowly than those of nondiabetic mice. Moreover, wound healing in diabetic mice treated with insulin exhibited a considerable delay. Peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) was used to detect biofilms on P. aeruginosa-infected wound tissues. Increased intracellular c-di-GMP levels promoted biofilm formation in wound tissues from nondiabetic mice. Greater biofilm formation was observed in the wounds of insulin-treated diabetic mice than in the wounds of untreated diabetic mice or nondiabetic mice, in both the PAO1/plac-yhjH- and PAO1-infected groups. Quantitative RT-PCR indicated that upon infection with PAO1/Plac-yhjH (the low c-di-GMP expression strain), the expression of IL-4 RNA was significantly higher in diabetic mice treated with insulin than in untreated diabetic mice or nondiabetic mice at each observation time point. Peak expression of IFN-γ occurred earlier in diabetic mice treated with insulin than in untreated diabetic mice with each of the experimental strains. Finally, P. aeruginosa harboring the plasmid pCdrA: gfp [s] was used as a reporter strain to monitor c-di-GMP levels. We found that insulin could promote biofilm formation by increasing intracellular c-di-GMP levels in vitro. Taken together, these data demonstrate that insulin treatment increases intracellular c-di-GMP levels, promotes biofilm formation and prolongs the inflammation period during the healing of infected wounds, resulting in delayed wound healing.}, } @article {pmid31311139, year = {2019}, author = {Nóbrega, V and Faria, M and Quintana, A and Kaufmann, M and Ferreira, A and Cordeiro, N}, title = {From a Basic Microalga and an Acetic Acid Bacterium Cellulose Producer to a Living Symbiotic Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {14}, pages = {}, pmid = {31311139}, issn = {1996-1944}, support = {REBECA (MAC/1.1a/060)//European Territorial Cooperation Programme PCT-MAC 2014-2020/ ; M1420-01-0145-FEDER-000001//Oceanic Observatory of Madeira/ ; }, abstract = {Bacterial cellulose (BC) has recently been the subject of a considerable amount of research, not only for its environmentally friendly biosynthesis, but also for its high potential in areas such as biomedicine or biomaterials. A symbiotic relationship between a photosynthetic microalga, Chlamydomonas debaryana, and a cellulose producer bacterium, Komagataeibacter saccharivorans, was established in order to obtain a viable and active biofilm. The effect of the growth media composition ratio on the produced living material was investigated, as well as the microalgae biomass quantity, temperature, and incubation time. The optimal temperature for higher symbiotic biofilm production was 30 °C with an incubation period of 14 days. The high microalgae presence, 0.75% w/v, and 60:40 HS:BG-11 medium (v/v) induced a biofilm microalgae incorporation rate of 85%. The obtained results report, for the first time, a successful symbiotic interaction developed in situ between an alkaline photosynthetic microalga and an acetic acid bacterium. These results are promising and open a new window to BC living biofilm applications in medical fields that have not yet been explored.}, } @article {pmid31310825, year = {2019}, author = {Cusicanqui Méndez, DA and Gutierrez, E and Campos Chaves Lamarque, G and Lopes Rizzato, V and Afonso Rabelo Buzalaf, M and Andrade Moreira Machado, MA and Cruvinel, T}, title = {The effectiveness of curcumin-mediated antimicrobial photodynamic therapy depends on pre-irradiation and biofilm growth times.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {474-480}, doi = {10.1016/j.pdpdt.2019.07.011}, pmid = {31310825}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Child ; Curcumin/*therapeutic use ; Dentin/*drug effects ; Female ; Humans ; Male ; Microbial Viability ; Photochemotherapy/*methods ; Photosensitizing Agents/*therapeutic use ; }, abstract = {BACKGROUND: The aim of this study was to determine the influence of distinct pre-irradiation times (PIT) of curcumin on the effectiveness of antimicrobial photodynamic therapy (aPDT) against intact dentin caries biofilms grown for 3 or 5 days.

METHODS: The microcosm biofilms grew on non-fluorescent glass blocks immersed in McBain medium with 1% sucrose, using microaerophilic conditions at 37 °C for 3 or 5 days. The biofilms were treated by the association of 600 μmol.L[-1] curcumin using different pre-irradiation times (1, 2 or 5 min) combined with 0 or 75 J.cm[-2] blue LED. Then, the vitality of biofilms was determined by confocal scanning laser microscopy (CSLM), after being stained with the mixture of ethidium bromide and fluorescein diacetate. Statistical analysis was performed by two-way ANOVA and post-hoc Tukey tests, after arcsine transformation (P < 0,05).

RESULTS: In comparison to control, curcumin alone (PIT = 5 min) and all combinations of curcumin and LED reduced significantly the vitality of 3-day biofilms. Distinctly, only curcumin plus LED using PITs of 2 or 5 min were effective in reducing the vitality of 5-day biofilms.

CONCLUSION: Curcumin-mediated aPDT significantly decreased the vitality of intact dentin caries microcosms grown during 3 or 5 days, although successful treatments of 5-day biofilms required longer PITs in comparison to their counterparts.}, } @article {pmid31303882, year = {2019}, author = {Bahari, M and Ebrahimi Chaharom, ME and Daneshpooy, M and Gholizadeh, S and Pashayi, H}, title = {Effect of bleaching protocols on surface roughness and biofilm formation on silorane-based composite resin.}, journal = {Dental research journal}, volume = {16}, number = {4}, pages = {264-270}, pmid = {31303882}, issn = {1735-3327}, abstract = {BACKGROUND: Knowledge about the effect of bleaching on behavior of composite resins is important to find a suitable composite resin for restoration of teeth undergoing bleaching. This study aimed to assess the effect of different bleaching protocols on surface roughness and biofilm formation on a silorane-based composite resin.

MATERIALS AND METHODS: In this in vitro experimental study, 60 silorane-based composite resin samples measuring 3 mm in thickness and 6 mm in diameter were fabricated and polished. They were then randomly divided into four groups (n = 15). In Group 1, samples were stored in distilled water as control. Samples in Groups 2, 3, and 4 were subjected to bleaching with 15% carbamide peroxide, 35% hydrogen peroxide, and 35% hydrogen peroxide activated by light, respectively. Surface roughness was measured using a profilometer. Streptococcus mutans cultured in brain-heart infusion broth was used for the assessment of biofilm formation on the samples. The bacterial colonies were counted using the pure-plate technique. Data were analyzed using one-way ANOVA and post hoc Tukey's tests. Regression model was used to assess the association between surface roughness and biofilm formation (P < 0.05).

RESULTS: The mean surface roughness of the four groups was not significantly different (P = 0.11); however, a significant difference was noted in the mean biofilm formation among the groups (P = 0.00).

CONCLUSION: Bleaching decreased biofilm formation. The lowest biofilm formation was noted in the group subjected to light-activated 35% hydrogen peroxide. Increased surface roughness enhanced biofilm formation to a certain level; excessive roughness did not increase biofilm formation.}, } @article {pmid31303772, year = {2019}, author = {Farajzadeh Sheikh, A and Asareh Zadegan Dezfuli, A and Navidifar, T and Fard, SS and Dehdashtian, M}, title = {Association between biofilm formation, structure and antibiotic resistance in Staphylococcus epidermidis isolated from neonatal septicemia in southwest Iran.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {1771-1782}, pmid = {31303772}, issn = {1178-6973}, abstract = {Background: Staphylococcus epidermidis has emerged as the pathogen from neonatal septicemia. Antibiotic resistance and the capability of biofilm formation make these infections much harder to treat. Hence, the aim of this study was to investigate the association between biofilm formation, structure and antibiotic resistance in S. epidermidis isolated from neonatal septicemia. Methods: Overall, 65 S. epidermidis isolates were recovered from blood cultures of neonatal septicemia. Antibiotic resistance pattern and the biofilm production were determined using phenotypic methods. The presence of ica operon, the bhp, the aap genes and SCCmec types were screened using PCR. Results: Most S.epidermidis isolates were resistant to erythromycin, while all isolates were sensitive to linezolid and vancomycin. Fifty-three percent of S.epidermidis isolates were resistant to methicillin. SCCmec types II was found commonly among methicillin-resistant S. epidermidis (MRSE) strains. The biofilm formation was observed in 65% of S.epidermidis isolates and the majority have polysaccharide matrix. icaA and icaD genes were found in 40% and 19% of isolates. Twenty-three isolates (62%) produced dissolvable polysaccharide intercellular adhesion (PIA)-dependent biofilms in SM after growth in TSB with NaCl and 14 (37%) isolates produced dissolvable protein-dependent biofilms in PK after growth in TSB with glucose. Three isolates (62%) produced dissolvable polysaccharide intercellular adhesion. Conclusion: Our data indicate the high rates of antibiotic resistance and the capability of biofilm formation among S. epidermidis isolates. Hence, the transmission of these strains can cause an increased risk of serious nosocomial infections.}, } @article {pmid31302463, year = {2019}, author = {Zhang, Q and Zhang, L and Li, Z and Zhang, L and Li, D}, title = {Enhancement of fipronil degradation with eliminating its toxicity in a microbial fuel cell and the catabolic versatility of anodic biofilm.}, journal = {Bioresource technology}, volume = {290}, number = {}, pages = {121723}, doi = {10.1016/j.biortech.2019.121723}, pmid = {31302463}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Pyrazoles ; }, abstract = {The degradation of fipronil was investigated in microbial fuel cells (MFCs). Almost 79% of 30 mg/L fipronil was rapidly degraded within 12 h by MFC biofilm. Based on the constructed quadratic polynomial model, a maximum fipronil degradation rate of 94.22% could be theoretically achieved at pH of 7.01, 33.39 °C, and the initial fipronil concentration 74 mg/L after incubation for 72 h. The high acute toxicity of fipronil toward zebrafish was largely eliminated after degradation by the MFC. In addition, the MFC biofilm showed catabolic versatility to 4-chloronitrobenzene, sulfanilamide, fluoroglycofen, and azoxystrobin. The microbial community analysis revealed that the functional bacteria Sphaerochaeta, Pseudomonas, Azospirillum, Azoarcus, and Chryseobacterium were major predominant bacteria in the anodic biofilm. Therefore, the MFC offers a promising approach in treating the environmental contaminants due to its abilities of energy capture from waste substances and catabolic versatility to different organic compounds.}, } @article {pmid31300852, year = {2019}, author = {Zara, G and Bou Zeidan, M and Fancello, F and Sanna, ML and Mannazzu, I and Budroni, M and Zara, S}, title = {The administration of L-cysteine and L-arginine inhibits biofilm formation in wild-type biofilm-forming yeast by modulating FLO11 gene expression.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {18}, pages = {7675-7685}, doi = {10.1007/s00253-019-09996-5}, pmid = {31300852}, issn = {1432-0614}, mesh = {Arginine/*pharmacology ; Biofilms/*drug effects ; Culture Media ; Cysteine/*pharmacology ; Gene Expression Regulation, Fungal ; Membrane Glycoproteins/*genetics ; Phenotype ; Saccharomyces cerevisiae/*drug effects/*genetics ; Saccharomyces cerevisiae Proteins/*genetics ; }, abstract = {Microbial biofilms are undesired in food manufacturing, drinking water distribution systems, and clinical realms. Yeast biofilms are particularly problematic because of the strong capacity of yeast cells to adhere to abiotic surfaces, cells, and tissues. Novel approaches have been developed over recent years to prevent the establishment of microbial biofilms, such as through the use of small molecules with inhibiting and dispersing properties. Here, we studied the inhibitory activity of 11 different amino acids on the biofilm formation ability of three wild-type Saccharomyces cerevisiae strains and the reference strain ∑1278b. Subsequent evaluation of different concentrations of the two most effective amino acids, namely, arginine and cysteine, revealed that they acted in different ways. Arginine prevented biofilm formation by reducing FLO11 gene expression; its addition did not affect cell viability and was even found to enhance cell metabolism (vitality marker) as determined by phenotype microarray (PM) analysis. On the contrary, the addition of cysteine reduced both cell viability and vitality as well as FLO11 expression. Thus, the use of cysteine and arginine as agents against biofilm formation can be diversified depending on the most desired action towards yeast growth.}, } @article {pmid31300301, year = {2021}, author = {Uribe-García, A and Paniagua-Contreras, GL and Monroy-Pérez, E and Bustos-Martínez, J and Hamdan-Partida, A and Garzón, J and Alanís, J and Quezada, R and Vaca-Paniagua, F and Vaca, S}, title = {Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {54}, number = {2}, pages = {267-275}, doi = {10.1016/j.jmii.2019.05.010}, pmid = {31300301}, issn = {1995-9133}, mesh = {Adhesins, Bacterial/drug effects/*genetics ; Anti-Bacterial Agents/pharmacology ; Antigens, Bacterial/genetics ; Biofilms/drug effects/*growth & development ; Cell Line ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Multiple, Bacterial/genetics ; Electrophoresis, Gel, Pulsed-Field ; Epithelial Cells ; Female ; Gene Expression Regulation, Bacterial ; Genotype ; Humans ; Male ; Mexico ; Microbial Sensitivity Tests ; Microbiota ; Mouth/microbiology ; Phenotype ; Polymerase Chain Reaction ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/*genetics/*isolation & purification/*metabolism ; Virulence/genetics ; }, abstract = {BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics.

METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro.

RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified.

CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.}, } @article {pmid31300167, year = {2019}, author = {Zhang, K and Lyu, L and Yao, S and Kang, T and Ma, Y and Pan, Y and Chang, M and Wang, Y and Furukawa, K and Zhu, T}, title = {Effects of vibration on anammox-enriched biofilm in a high-loaded upflow reactor.}, journal = {The Science of the total environment}, volume = {685}, number = {}, pages = {1284-1293}, doi = {10.1016/j.scitotenv.2019.06.082}, pmid = {31300167}, issn = {1879-1026}, mesh = {Ammonium Compounds/metabolism ; *Biofilms ; *Bioreactors ; Vibration ; Waste Disposal, Fluid/*methods ; }, abstract = {An upflow biofilm reactor was operated for 211 days to investigate the effects of vibration on anammox treatment performance. With vibration, the highest nitrogen removal rates (20 kg-N·m[-3]·d[-1]) were obtained on day 180. Since the vibration could directly applied on the biofilm, it could release the dinitrogen gas accumulated in the biofilm timely and reduce the internal mass transfer resistance sharply. The specific anammox activity increased by more than 3 times with a higher vibration intensity. Meanwhile, the unique random motion caused by mechanical vibration promotes the production of extracellular proteins. Moreover, the VSS reached 20.97 g·L[-1] which was 1.6 times higher than the control reactor. Such enrichment method resulted in a hard and thick anammox biofilm with a special granular morphology, and the nitrite tolerance concentration could reach 500 mg-N·L[-1]. Operated with an adequate vibration intensity could maintain the biofilm thickness and conducive to improve the stability of the reactor. In addition, this technique also allowed the microorganisms inside the biofilm and those on the surface to reach the same culture conditions. Base on the batch experiments, intermittent vibration caused a decrease in energy consumption from about 7.757 (kW·h)·(kg-N)[-1] in group 0-Lv7(60-60) to 0.912 (kW·h)·(kg-N)[-1] in group 0-Lv7(5-60). Compared to the internal recycle without vibration, the energy consumption fell by a slice over 65%. Furthermore, the high-throughput sequencing results showed that the relative abundance of Candidatus Kuenenia in reactor 1 increased from 13.2% to 43.9%.}, } @article {pmid31299899, year = {2019}, author = {Azmi, K and Qrei, W and Abdeen, Z}, title = {Screening of genes encoding adhesion factors and biofilm production in methicillin resistant strains of Staphylococcus aureus isolated from Palestinian patients.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {578}, pmid = {31299899}, issn = {1471-2164}, support = {(M33-014).//Merck/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Arabs/*genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cell Adhesion Molecules/*genetics ; Genes, Bacterial/*genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/*physiology ; Polymerase Chain Reaction ; Trans-Activators/genetics ; }, abstract = {BACKGROUND: Intercellular adhesion and biofilm production by Staphylococcus aureus makes these bacteria resistant to antimicrobial therapy. Here, Methicillin-resistant Staphylococcus aureus (MRSA) strains were characterized and the prevalence of genes encoding adhesion factors and biofilm formation was determined.

RESULTS: All 248 MRSA isolates identified by cefoxitin disc diffusion were positive for the mecA gene. SCCmec-IV was the most frequently detected genotype (92.7%) and SCCmec-IVa was also very prevalent (84.3%). The quantitative microtiter plate assay showed that all the isolates were able to produce biofilm with levels ranging from high (21%) to moderate (46.4%) to low (32.7%). All the strains possessed the icaD/icaA genes and produced biofilm (P < 0.05). None of the isolates possessed the bap gene. Furthermore, 94.8% of the isolates were positive for eno, 80.2% for clfA and for clfB, 78.2% for fnbA, 76.2% for ebps, 62.2% for fib, 39.9% for cna and 29.0% for fnbB. Also, nearly 69.8% of the isolates were positive for the gene sarA. All four agr groups were present: agr group 1 was predominant with 39.5%; agr group 3. agr group 2 and 3 strains carried more toxin-producing genes, and frequently produced more toxin. Sixty-six (26.6%) of the strains were multidrug resistant. All were vancomycin sensitive. Agr group I is more resistant to ciprofloxacin and gentamicin while agr group III is more resistant to erythromycin. Maximum sensitivity was to gentamicin and SXT, and they could be considered drugs of choice for controlling MRSA mediated infections in this region.

CONCLUSIONS: Biofilm development in MRSA might be an ica dependent and one needs to investigate the involvement of other global regulators, agr and sarA, and their contribution to the biofilm phenotype, as the high rate of biofilm production among the studied strains of S. aureus.}, } @article {pmid31297368, year = {2019}, author = {Nichols, D and Pimentel, MB and Borges, FTP and Hyoju, SK and Teymour, F and Hong, SH and Zaborina, OY and Alverdy, JC and Papavasiliou, G}, title = {Sustained Release of Phosphates From Hydrogel Nanoparticles Suppresses Bacterial Collagenase and Biofilm Formation in vitro.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {7}, number = {}, pages = {153}, pmid = {31297368}, issn = {2296-4185}, support = {P30 DK042086/DK/NIDDK NIH HHS/United States ; R01 GM062344/GM/NIGMS NIH HHS/United States ; R21 AI124037/AI/NIAID NIH HHS/United States ; }, abstract = {Intestinal disease or surgical intervention results in local changes in tissue and host-derived factors triggering bacterial virulence. A key phenotype involved in impaired tissue healing is increased bacterial collagenase expression which degrades intestinal collagen. Antibiotic administration is ineffective in addressing this issue as it inadvertently eliminates normal flora while allowing pathogenic bacteria to "bloom" and acquire antibiotic resistance. Compounds that could attenuate collagenase production while allowing commensal bacteria to proliferate normally would offer major advantages without the risk of the emergence of resistance. We have previously shown that intestinal phosphate depletion in the surgically stressed host is a major cue that triggers P. aeruginosa virulence which is suppressed under phosphate abundant conditions. Recent findings indicate that orally administered polyphosphate, hexametaphosphate, (PPi) suppresses collagenase, and biofilm production of P. aeruginosa and S. marcescens in animal models of intestinal injury but does not attenuate E. faecalis induced collagenolytic activity (Hyoju et al., 2017). Systemic administration of phosphates, however, is susceptible to rapid clearance. Given the diversity of collagenase producing bacteria and the variation of phosphate metabolism among microbial species, a combination therapy involving different phosphate compounds may be required to attenuate pathogenic phenotypes. To address these barriers, we present a drug delivery approach for sustained release of phosphates from poly(ethylene) glycol (PEG) hydrogel nanoparticles. The efficacy of monophosphate (Pi)- and PPi-loaded NPs (NP-Pi and NP-PPi, respectively) and a combination treatment (NP-Pi + NP-PPi) in mitigating collagenase and biofilm production of gram-positive and gram-negative pathogens expressing high collagenolytic activity was investigated. NP-PPi was found to significantly decrease collagenase and biofilm production of S. marcescens and P. aeruginosa. Treatment with either NP-Pi or NP-Pi + NP-PPi resulted in more prominent decreases in E. faecalis collagenase compared to NP-PPi alone. The combination treatment was also found to significantly reduce P. aeruginosa collagenase production. Finally, significant attenuation in biofilm dispersal was observed with NP-PPi or NP-Pi + NP-PPi treatment across all test pathogens. These findings suggest that sustained release of different forms of phosphate confers protection against gram-positive and gram-negative pathogens, thereby providing a promising treatment to attenuate expression of tissue-disruptive bacterial phenotypes without eradicating protective flora over the course of intestinal healing.}, } @article {pmid31297098, year = {2019}, author = {Friedlander, A and Nir, S and Reches, M and Shemesh, M}, title = {Preventing Biofilm Formation by Dairy-Associated Bacteria Using Peptide-Coated Surfaces.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1405}, pmid = {31297098}, issn = {1664-302X}, abstract = {Biofilm-forming bacteria, which colonize the surfaces of equipment in the dairy industry, may adversely affect the safety and quality of the milk and its products. Despite numerous efforts to combat biofilm formation, there is still no effective technological means to thoroughly solve the biofilm problem in the dairy industry. Here, we introduced peptide-based coating in order to modify the physical properties of the stainless steel surface by affecting its availability for bacterial adhesion. We found that the coated surface displays a notable decrease in the ability of bacterial cells to attach and to subsequently form biofilm by Gram-positive Bacillus licheniformis and Gram-negative Pseudomonas aeruginosa. Furthermore, the coated surface retained its anti-biofilm ability following its exposure to raw milk. Importantly, the modified surface did not affect the milk coagulation process or its nutritious properties and quality. Overall, this anti-biofilm approach may serve as an attractive solution for the dairy industry in its struggle against bacterial contamination.}, } @article {pmid31297021, year = {2019}, author = {Al-Yousef, HM and Sheikh, IA}, title = {β-Sitosterol derived compound from onion husks non-polar fraction reduces quorum sensing controlled virulence and biofilm production.}, journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society}, volume = {27}, number = {5}, pages = {664-672}, pmid = {31297021}, issn = {1319-0164}, abstract = {Quorum sensing is an important regulatory factor of P. aeruginosa virulence induction such as BF, motility, formations of proteases, pyocyanin, and some toxins. The aim of the current study is to detect the effect of the pet.ether extract from onion husk and compound drive from it on quorum sensing and virulence formations of P. aeruginosa. Quorum sensing inhibiting effect of the pet.ether extract of onion husk and a compound drive from it, was evaluated by C. violaceum reporter using dilution method as well as an antioxidant by using DPPH. The efficacious of: Quorum sensing inhibiting on pet.ether fraction and compound derived from it, were investigated for their activities toward biofilm and pyocyanin synthesis as well as motility from P. aeruginosa. The pet.ether fraction and compound derived from it of onion husk exhibited potent antimicrobial, antioxidant and Quorum sensing inhibiting effects. The pet.ether fraction and compound derived from it possesses significant reduction on pyocyanin and biofilm induction of P. aeruginosa. Moreover, they significantly inhibited swimming motilities of P. aeruginosa. For the first time, our study showed the medical importance of Allium cepa L. as antimicrobial, antioxidant as well as Quorum sensing inhibiting and virulence suppressors of P. aeruginosa. Thus, these might emphasized on Allium cepa L as a natural source for attenuating toxins of the Pseudomonas.}, } @article {pmid31295074, year = {2019}, author = {Carter, MJ and Myntti, MF}, title = {Cost-utility of a biofilm-disrupting gel versus standard of care in chronic wounds: a Markov microsimulation model based on a randomised controlled trial.}, journal = {Journal of wound care}, volume = {28}, number = {Sup7}, pages = {S24-S38}, doi = {10.12968/jowc.2019.28.Sup7.S24}, pmid = {31295074}, issn = {0969-0700}, mesh = {*Biofilms ; Chronic Disease ; Cost-Benefit Analysis ; Female ; Gels/pharmacology ; Humans ; Male ; Standard of Care/*economics ; Wound Healing/*physiology ; Wounds and Injuries/diagnosis/*economics/*therapy ; }, abstract = {OBJECTIVE: Analyse the cost-effectiveness and treatment outcomes of debridement (standard of care) plus BlastX, a biofilm-disrupting wound gel (group 1) or a triple-antibiotic, maximum-strength ointment (group 2), comparing a subset of patients who had not healed at four weeks using the ointment crossed-over to the biofilm-disrupting gel (group 3).

METHODS: A series of Markov microsimulation models were built using health states of an unhealed non-infected ulcer, healed ulcer, and infected non-healed ulcer and absorbing states of dead or amputation. All patients started with unhealed non-infected ulcers at cycle 0. Complications and healing rates were based on a randomised controlled trial (RCT). Costs were incurred by patients for procedures at outpatient wound care clinics and hospitals (if complications occurred) and were in the form of Medicare allowable charges. Quality-adjusted life years (QALYs) were computed using literature utility values. Incremental cost-effectiveness ratios (ICERs) were calculated for group 1 versus group 2, and group 3 versus group 2. One-way, multi-way and probabilistic sensitivity analysis (PSA) was conducted.

RESULTS: After one year, the base case ICER was $8794 per QALY for group 1 versus group 2, and $21,566 per QALY for group 3 versus group 2. Product cost and amputation rates had the most influence in one-way sensitivity analysis. PSA showed that the majority of costs were higher for group 1 but effectiveness values were always higher than for group 2. Average product use of 3.1ml per application represented 9.4% of the total group 1 cost (average $24.52 per application/$822.50 per group 1 patient). The biofilm-disrupting gel group performed substantially better than the current cost-effectiveness benchmarks, $8794 versus $50,000, respectively. Furthermore, when biofilm-disrupting gel treatment was delayed, as in group 3, the ICER outcomes were less substantial but it did remain cost-effective, suggesting the added benefits of immediate use of biofilm-disrupting gel. Also, when product cost assumptions used in the study were halved (Wolcott study usage), the model indicates important reductions in ICER to $966/QALY when comparing group 1 with group 2. It should be noted that product cost can hypothetically be affected not only by direct product purchase costs, but also by application intervals and technique. This suggests additional opportunities exist to optimise these parameters, maximising wound healing efficacy while providing significant cost savings to the payer.

CONCLUSION: The addition of the biofilm-disrupting gel treatment to standard of care is likely to be cost-effective in the treatment of chronic wounds but when delayed by as little as 9-12 weeks the ICER is still far less than current cost-effectiveness benchmarks. The implication for payers and decision-makers is that biofilm-disrupting gel should be used as a first-line therapy at the first clinic visit rather than waiting as it substantially decreases cost-utility.}, } @article {pmid31294965, year = {2019}, author = {Alizadeh, S and Abdul Rahim, A and Guo, B and Hawari, J and Ghoshal, S and Comeau, Y}, title = {Impacts of Continuous Inflow of Low Concentrations of Silver Nanoparticles on Biological Performance and Microbial Communities of Aerobic Heterotrophic Wastewater Biofilm.}, journal = {Environmental science & technology}, volume = {53}, number = {15}, pages = {9148-9159}, doi = {10.1021/acs.est.9b01214}, pmid = {31294965}, issn = {1520-5851}, mesh = {Biofilms ; *Metal Nanoparticles ; *Microbiota ; Silver ; Wastewater ; }, abstract = {Attached-growth wastewater processes are currently used in water resource recovery facilities (WRRFs) for required upgrades due to an increase in influent loading or to reach more stringent discharge criteria. Yet, the distribution and long-term inhibitory effects of silver nanoparticles (AgNPs) in attached-growth biological wastewater processes and their impact on involved microbial communities are poorly understood at relevant, low concentrations. Retention, distribution, and long-term inhibitory effect of polyvinylpyrrolidone (PVP)-coated AgNPs were evaluated in bench-scale moving bed biofilm reactors (MBBRs), achieving soluble organic matter removal, over a 64 day exposure to nominal concentrations of 10 and 100 μg/L. Distributions of continuously added AgNPs were characterized in the influent, bioreactor, and effluent of MBBRs using single particle inductively coupled plasma mass spectroscopy (spICP-MS). Aerobic heterotrophic biofilms in MBBRs demonstrated limited retention capacity for AgNPs over long-term exposure, with release of AgNPs, and Ag-rich biofilm sloughed from the carriers. Continuous exposure to both influent AgNP concentrations significantly decreased soluble chemical oxygen demand (SCOD) removal efficiency (11% to 31%) and reduced biofilm viability (8% to 30%). Specific activities of both intracellular dehydrogenase (DHA) and extracellular α-glucosidase (α-Glu) and protease (PRO) enzymes were significantly inhibited (8% to 39%) with an observed NP dose-dependent intracellular reactive oxygen species (ROS) production and shift in biofilm microbial community composition by day 64. Our results indicated that long-term exposure to AgNPs in biofilm processes at environmentally relevant concentrations can impact the treatment process stability and the quality of the discharged effluent.}, } @article {pmid31294223, year = {2018}, author = {Xaxiri, NA and Nikouli, E and Berillis, P and Kormas, KA}, title = {Bacterial biofilm development during experimental degradation of Melicertus kerathurus exoskeleton in seawater.}, journal = {AIMS microbiology}, volume = {4}, number = {3}, pages = {397-412}, pmid = {31294223}, issn = {2471-1888}, abstract = {Chitinolytic bacteria are widespread in marine and terrestrial environment, and this is rather a reflection of their principle growth substrate's ubiquity, chitin, in our planet. In this paper, we investigated the development of naturally occurring bacterial biofilms on the exoskeleton of the shrimp Melicertus kerathurus during its degradation in sea water. During a 12-day experiment with exoskeleton fragments in batch cultures containing only sea water as the growth medium at 18 °C in darkness, we analysed the formation and succession of biofilms by scanning electron microscopy and 16S rRNA gene diversity by next generation sequencing. Bacteria belonging to the γ- and α-Proteobacteria and Bacteroidetes showed marked (less or more than 10%) changes in their relative abundance from the beginning of the experiment. These bacterial taxa related to known chitinolytic bacteria were the Pseudolateromonas porphyrae, Halomonas aquamarina, Reinekea aestuarii, Colwellia asteriadis and Vibrio crassostreae. These bacteria could be considered as appropriate candidates for the degradation of chitinous crustacean waste from the seafood industry as they dominated in the biofilms developed on the shrimp's exoskeleton in natural sea water with no added substrates and the degradation of the shrimp exoskeleton was also evidenced.}, } @article {pmid31294028, year = {2019}, author = {Coelho, C and Gougeon, RD and Perepelkine, L and Alexandre, H and Guzzo, J and Weidmann, S}, title = {Chemical Transfers Occurring Through Oenococcus oeni Biofilm in Different Enological Conditions.}, journal = {Frontiers in nutrition}, volume = {6}, number = {}, pages = {95}, pmid = {31294028}, issn = {2296-861X}, abstract = {Chardonnay wine malolactic fermentations were carried out to evaluate the chemical transfers occurring at the wood/wine interface in the presence of two different bacterial lifestyles. To do this, Oenococcus oeni was inoculated into must and wine in its planktonic and biofilm lifestyles, whether adhering or not to oak chips, leading to three distinct enological conditions: (i) post-alcoholic fermentation inoculation in wine in the absence of oak chips, (ii) post-alcoholic fermentation inoculation in wine in the presence of oak chips, and (iii) co-inoculation of both Saccharomyces cerevisiae and O. oeni directly in Chardonnay musts in the presence of oak chips. Classical microbiological and physico-chemical parameters analyzed during the fermentation processes confirmed that alcoholic fermentation was completed identically regardless of the enological conditions, and that once O. oeni had acquired a biofilm lifestyle in the presence or absence of oak, malolactic fermentation occurred faster and with better reproducibility compared to planktonic lifestyles. Analyses of volatile components (higher alcohols and wood aromas) and non-volatile components (Chardonnay grape polyphenols) carried out in the resulting wines revealed chemical differences, particularly when bacterial biofilms were present at the wood interface. This study revealed the non-specific trapping activity of biofilm networks in the presence of wood and grape compounds regardless of the enological conditions. Changes of concentrations in higher alcohols reflected the fermentation bioactivity of bacterial biofilms on wood surfaces. These chemical transfers were statistically validated by an untargeted approach using Excitation Emission Matrices of Fluorescence combined with multivariate analysis to discriminate innovative enological practices during winemaking and to provide winemakers with an optical tool for validating the biological and chemical differentiations occurring in wine that result from their decisions.}, } @article {pmid31293539, year = {2019}, author = {Schiffer, C and Hilgarth, M and Ehrmann, M and Vogel, RF}, title = {Bap and Cell Surface Hydrophobicity Are Important Factors in Staphylococcus xylosus Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1387}, pmid = {31293539}, issn = {1664-302X}, abstract = {Staphylococcus (S.) xylosus is a coagulase-negative Staphylococcus species naturally present in food of animal origin with a previously described potential for biofilm formation. In this study we characterized biofilm formation of five selected strains isolated from raw fermented dry sausages, upon different growth conditions. Four strains exhibited a biofilm positive phenotype with strain-dependent intensities. Biofilm formation of S. xylosus was influenced by the addition of glucose, sodium chloride and lactate to the growth medium, respectively. It was further dependent on strain-specific cell surface properties. Three strains exhibited hydrophobic and two hydrophilic cell surface properties. The biofilm positive hydrophilic strain TMW 2.1523 adhered significantly better to hydrophilic than to hydrophobic supports, whereas the differences in adherence to hydrophobic versus hydrophilic supports were not as distinct for the hydrophobic strains TMW 2.1023, TMW 2.1323, and TMW 2.1521. Comparative genomics enabled prediction of functional biofilm-related genes and link these to phenotypic variations. While a wide range of biofilm associated factors/genes previously described for S. aureus and S. epidermidis were absent in the genomes of the five strains analyzed, they all possess the gene encoding biofilm associated protein Bap. The only biofilm negative strain TMW 2.1602 showed a mutation in the bap sequence. This study demonstrates that Bap and surface hydrophobicity are important factors in S. xylosus biofilm formation with potential impact on the assertiveness of a starter strain against autochthonous staphylococci by competitive exclusion during raw sausage fermentation.}, } @article {pmid31293526, year = {2019}, author = {Gannesen, AV and Zdorovenko, EL and Botchkova, EA and Hardouin, J and Massier, S and Kopitsyn, DS and Gorbachevskii, MV and Kadykova, AA and Shashkov, AS and Zhurina, MV and Netrusov, AI and Knirel, YA and Plakunov, VK and Feuilloley, MGJ}, title = {Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1284}, pmid = {31293526}, issn = {1664-302X}, abstract = {In skin, Cutibacterium acnes (former Propionibacterium acnes) can behave as an opportunistic pathogen, depending on the strain and environmental conditions. Acneic strains of C. acnes form biofilms inside skin-gland hollows, inducing inflammation and skin disorders. The essential exogenous products of C. acnes accumulate in the extracellular matrix of the biofilm, conferring essential bacterial functions to this structure. However, little is known about the actual composition of the biofilm matrix of C. acnes. Here, we developed a new technique for the extraction of the biofilm matrix of Gram-positive bacteria without the use of chemical or enzymatic digestion, known to be a source of artifacts. Our method is based on the physical separation of the cells and matrix of sonicated biofilms by ultracentrifugation through a CsCl gradient. Biofilms were grown on the surface of cellulose acetate filters, and the biomass was collected without contamination by the growth medium. The biofilm matrix of the acneic C. acnes RT5 strain appears to consist mainly of polysaccharides. The following is the ratio of the main matrix components: 62.6% polysaccharides, 9.6% proteins, 4.0% DNA, and 23.8% other compounds (porphyrins precursors and other). The chemical structure of the major polysaccharide was determined using a nuclear magnetic resonance technique, the formula being →6)-α-D-Galp-(1→4)-β-D-ManpNAc3NAcA-(1→6)-α-D-Glcp-(1→4)-β-D-ManpNAc3NAcA-(1→3)-β-GalpNAc-(1→. We detected 447 proteins in the matrix, of which the most abundant were the chaperonin GroL, the elongation factors EF-Tu and EF-G, several enzymes of glycolysis, and proteins of unknown function. The matrix also contained more than 20 hydrolases of various substrata, pathogenicity factors, and many intracellular proteins and enzymes. We also performed surface-enhanced Raman spectroscopy analysis of the C. acnes RT5 matrix for the first time, providing the surface-enhanced Raman scattering (SERS) profiles of the C. acnes RT5 biofilm matrix and biofilm biomass. The difference between the matrix and biofilm biomass spectra showed successful matrix extraction rather than simply the presence of cell debris after sonication. These data show the complexity of the biofilm matrix composition and should be essential for the development of new anti-C. acnes biofilms and potential antibiofilm drugs.}, } @article {pmid31292867, year = {2019}, author = {Calapez, AR and Elias, CL and Almeida, SFP and Brito, AG and Feio, MJ}, title = {Sewage contamination under water scarcity effects on stream biota: biofilm, grazers, and their interaction.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {26}, pages = {26636-26645}, pmid = {31292867}, issn = {1614-7499}, support = {PD\BD\52510\2014//Fundação para a Ciência e a Tecnologia/ ; UID/MAR/04292/2013//Fundação para a Ciência e a Tecnologia/ ; UID/GEO/04035/2013//Fundação para a Ciência e a Tecnologia/ ; }, mesh = {Biofilms/*growth & development ; Biomass ; *Biota ; Chlorophyll/analogs & derivatives/analysis ; *Conservation of Water Resources ; Diatoms ; Ecosystem ; Rhodophyta/*physiology ; Rivers ; Sewage/*chemistry ; Waste Disposal Facilities ; Water Pollutants/*toxicity ; *Water Supply ; }, abstract = {One of the most common anthropogenic impacts on river ecosystems is the effluent discharge from wastewater treatment plants. The effects of this contamination on stream biota may be intensified in Mediterranean climate regions, which comprise a drought period that leads to flow reduction, and ultimately to stagnant pools. To assess individual and combined effects of flow stagnation and sewage contamination, biofilm and gastropod grazers were used in a 5-week experiment with artificial channels to test two flow velocity treatments (stagnant flow/basal flow) and two levels of organic contamination using artificial sewage (no sewage input/sewage input). Stressors' effects were determined on biofilm total biomass and chlorophyll (Chl) content, on oxygen consumption and growth rate of the grazers (Theodoxus fluviatilis), and on the interaction grazer-biofilm given by grazer's feeding activity (i.e., biofilm consumption rate). The single effect of sewage induced an increase in biofilm biomass and Chl-a content, simultaneously increasing both grazers' oxygen consumption and their feeding activity. Diatoms showed a higher sensitivity to flow stagnation, resulting in a lower content of Chl-c. Combined stressors interacted antagonistically for biofilm total biomass, Chl-b contents, and grazers's feeding rate. The effect of sewage increasing biofilm biomass and grazing activity was reduced by the presence of flow stagnation (antagonist factor). Our findings suggest that sewage contamination has a direct effect on the functional response of primary producers and an indirect effect on primary consumers, and this effect is influenced by water flow stagnation.}, } @article {pmid31291096, year = {2019}, author = {Wang, M and Shi, J and Mao, H and Sun, Z and Guo, S and Guo, J and Yan, F}, title = {Fluorescent Imidazolium-Type Poly(ionic liquid)s for Bacterial Imaging and Biofilm Inhibition.}, journal = {Biomacromolecules}, volume = {20}, number = {8}, pages = {3161-3170}, doi = {10.1021/acs.biomac.9b00741}, pmid = {31291096}, issn = {1526-4602}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects/*growth & development ; Escherichia coli/drug effects/*physiology ; *Fluorescence ; Imidazoles/*chemistry ; Ionic Liquids/chemistry/*pharmacology ; Molecular Imaging/methods ; Polymers/chemistry ; Staphylococcus aureus/drug effects/*growth & development ; }, abstract = {Fluorescent imidazolium-type poly(ionic liquid)s (PIL)s were synthesized by anion exchange of bromide (Br[-]) in poly(3-butyl-1-vinylimidazolium bromide) (PIL-Br) with a fluorescent anion, namely, 3-(4-(1,2,2-triphenylvinyl)phenoxy)propane-1-sulfonate (TPESO3[-]). Such an anion exchange provided antibacterial PILs with aggregation-induced emission (AIE) properties that simultaneously kill and image bacteria. These fluorescence and antibacterial properties could be regulated by controlling the Br[-]/TPESO3[-] ratio. The fluorescence intensity increases as this ratio increases, while the antibacterial property exhibits an opposite trend. Moreover, the AIE-type PILs are useful for fluorescently imaging dead bacteria (macroscopically and microscopically) and could effectively inhibit biofilm growth. This study provided a convenient method to obtain fluorescent PILs with adjustable antibacterial and imaging properties.}, } @article {pmid31290732, year = {2019}, author = {Süß, M and De Visscher, A}, title = {Effect of diffusion limitation and substrate inhibition on steady states of a biofilm reactor treating a single pollutant.}, journal = {Journal of the Air & Waste Management Association (1995)}, volume = {69}, number = {9}, pages = {1107-1115}, doi = {10.1080/10962247.2019.1631904}, pmid = {31290732}, issn = {2162-2906}, mesh = {Biodegradation, Environmental ; *Biofilms ; *Bioreactors ; Diffusion ; Environmental Pollutants/analysis/*metabolism ; Kinetics ; Models, Chemical ; Toluene/analysis/*metabolism ; }, abstract = {The occurrence of multiple steady states in a toluene biodegrading, diffusion-limited biofilm under aerobic conditions was investigated by computer models: one steady-state, and one nonsteady-state. Two stable and one unstable intermediate steady-state were identified in a narrow set of combinations of parameters values. The nonsteady-state model predicts conditions that evolve to a steady state that is within 0.02-1% of the solution of the steady-state model, depending on the number of grid points used, confirming the algorithms are valid. Multiple steady states occur if, (1) a biofilm is exposed to a constant gas-phase pollution concentration, which exceeds or undershoots a certain threshold, (2) in a narrow range of parameter values and (3) provided that the pollutant degradation follows Haldane kinetics. Such a biofilm displays half-saturation (i.e., Michaelis-Menten)-like apparent ("falsified") kinetics from a concentration range starting at zero up to the occurrence of a second steady state. Multiple steady states and falsified kinetics can negatively affect a biofilter and the experimental determination of kinetic parameters, respectively. Implications: The occurrence of multiple steady states in a VOC treating biofilm, shows the significant impact of degradation kinetics and diffusion limitation on the biofilm behavior. Moreover, the implied possible sudden drop of removal efficiency of a biofilter, based on the occurrence of multiple steady states lead to possible bottle-necks in biofilter application and operation.}, } @article {pmid31289312, year = {2019}, author = {Lim, ES and Koo, OK and Kim, MJ and Kim, JS}, title = {Bio-enzymes for inhibition and elimination of Escherichia coli O157:H7 biofilm and their synergistic effect with sodium hypochlorite.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {9920}, pmid = {31289312}, issn = {2045-2322}, mesh = {Biofilms/drug effects/*growth & development ; Cellulase/*metabolism ; Deoxyribonuclease I/*metabolism ; *Drug Synergism ; Endopeptidase K/*metabolism ; Escherichia coli O157/drug effects/*growth & development/metabolism ; Oxidants/pharmacology ; Sodium Hypochlorite/*pharmacology ; }, abstract = {Escherichia coli O157:H7 is one of the most important pathogens worldwide. In this study, three different kinds of enzymes, DNase I, proteinase K and cellulase were evaluated for inhibitory or degrading activity against E. coli O157:H7 biofilm by targeting extracellular DNA, proteins, and cellulose, respectively. The cell number of biofilms formed under proteinase K resulted in a 2.43 log CFU/cm[2] reduction with an additional synergistic 3.72 log CFU/cm[2] reduction after NaClO post-treatment, while no significant reduction occurred with NaClO treatment alone. It suggests that protein degradation could be a good way to control the biofilm effectively. In preformed biofilms, all enzymes showed a significant reduction of 16.4-36.7% in biofilm matrix in 10-fold diluted media (p < 0.05). The sequential treatment with proteinase K, cellulase, and NaClO showed a significantly higher synergistic inactivation of 2.83 log CFU/cm[2] compared to 1.58 log CFU/cm[2] in the sequence of cellulase, proteinase K, and NaClO (p < 0.05). It suggests that the sequence of multiple enzymes can make a significant difference in the susceptibility of biofilms to NaClO. This study indicates that the combination of extracellular polymeric substance-degrading enzymes with NaClO could be useful for the efficient control of E. coli O157:H7 biofilms.}, } @article {pmid31288972, year = {2020}, author = {Tsai, MH and Liang, YH and Chen, CL and Chiu, CH}, title = {Characterization of Salmonella resistance to bile during biofilm formation.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {53}, number = {4}, pages = {518-524}, doi = {10.1016/j.jmii.2019.06.003}, pmid = {31288972}, issn = {1995-9133}, mesh = {Bacterial Proteins/genetics/metabolism ; Bile/*metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Humans ; Salmonella Infections/microbiology ; Salmonella typhimurium/*genetics/*metabolism ; *Signal Transduction ; }, abstract = {BACKGROUND: Non-typhoid Salmonella infection may present as acute gastroenteritis or chronic infection, primarily in the bile-rich gallbladder. Biofilm formation is a mechanism of bile resistance in Salmonella. Our aim was to determine how Salmonella utilizes bile as a signal, and to study the relevance of the interaction between the PhoP-PhoQ two-component system and cyclic diguanosine monophosphate (c-di-GMP) signaling to biofilm formation.

METHODS: Two-dimensional (2-D) gel electrophoresis was used to identify genes required for Salmonella biofilm formation in bile. Quantitative real-time PCR (qRT-PCR) was used to clarify the role of the PhoP-PhoQ two-component system and its interaction with genes involved in the c-di-GMP network during biofilm formation.

RESULTS: Our result revealed that Salmonella mutants with incomplete outer membrane (△ompA), defective flagella (△flgE), or incomplete PhoP-PhoQ two-component system (△phoP), were unable to develop complete biofilms in the presence of bile. Moreover, PhoP-PhoQ two-component system-related Salmonella mutants (△phoP, △phoQ, △phoP△phoQ) had lower expression of c-di-GMP related genes (csgD, adrA) than the wild-type Salmonella strain had in the bile environment.

CONCLUSION: Salmonella may sense and respond to bile through the PhoP-PhoQ two-component system during biofilm formation. Furthermore, the PhoP-PhoQ two-component system might activate regulators of the c-di-GMP signaling network.}, } @article {pmid31288325, year = {2019}, author = {Wu, F and Li, MC and Sun, CC and Liu, Y and Wu, LG}, title = {[Influence of environmental factors on the two-species biofilm formed by Streptococcus oligofermentans and Streptococcus mutans].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {54}, number = {7}, pages = {456-462}, doi = {10.3760/cma.j.issn.1002-0098.2019.07.005}, pmid = {31288325}, issn = {1002-0098}, mesh = {*Biofilms ; *Environment ; Hydrogen-Ion Concentration ; *Microbial Interactions/physiology ; *Mouth/microbiology ; Oxygen/pharmacology ; Saliva/microbiology ; *Streptococcus/drug effects ; *Streptococcus mutans/drug effects ; Streptococcus sanguis/drug effects ; Sucrose/pharmacology ; }, abstract = {Objective: To study the influence of environmental factors on the two-species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods: Single-and two-species biofilms were grown on saliva-coated surfaces (glass tube and 96-well plate). Colony-counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results: Comparing the numbers of Sm in two co-cultures under various conditions, Sm counts in So+Sm group [(7.70±2.46)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(9.00±1.13)×10(8) CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×10(8) CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×10(8) CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×10(8) CFU/ml] were significantly higher than those in Ss+Sm group [(7.50±1.73)×10(8) CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70±2.94)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21) ×10(8) CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×10(8) CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×10(8) CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50±1.50)×10(8) CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×10(8) CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions: In the in vitro two-species co-culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.}, } @article {pmid31287946, year = {2019}, author = {Xiang, Z and Li, Z and Ren, Z and Zeng, J and Peng, X and Li, Y and Li, J}, title = {EzrA, a cell shape regulator contributing to biofilm formation and competitiveness in Streptococcus mutans.}, journal = {Molecular oral microbiology}, volume = {34}, number = {5}, pages = {194-208}, doi = {10.1111/omi.12264}, pmid = {31287946}, issn = {2041-1014}, mesh = {*Bacterial Proteins/physiology ; Biofilms ; Cell Division ; Cell Shape ; *Dental Caries/microbiology ; Humans ; *Streptococcus mutans/genetics/physiology ; }, abstract = {Bacterial cell division is initiated by tubulin homologue FtsZ that assembles into a ring structure at mid-cell to facilitate cytokinesis. EzrA has been identified to be implicated in FtsZ-ring dynamics and cell wall biosynthesis during cell division of Bacillus subtilis and Staphylococcus aureus, the model rod and cocci. However, its role in pathogenic streptococci remains largely unknown. Here, the role of EzrA was investigated in Streptococcus mutans, the primary etiological agent of human dental caries, by constructing an ezrA in-frame deletion mutant. Our data showed that the ezrA mutant was slow-growing with a shortened length and extended width round cell shape compared to the wild type, indicating a delay in cell division with abnormalities of peptidoglycan biosynthesis. Additionally, FtsZ irregularly localized in dividing ezrA mutant cells forming angled division planes, potentially contributing to an aberrant cell shape. Furthermore, investigation using single-species cariogenic biofilm model revealed that deletion of ezrA resulted in defective biofilm formation with less extracellular polysaccharides and altered three-dimensional biofilm architecture. Unexpectedly, in a dual-species ecological model, the ezrA mutant exhibited substantially lower tolerance for H2 O2 and reduced competitiveness against one commensal species, Streptococcus sanguinis. Taken together, these results demonstrate that EzrA plays a key role in regulating cell division and maintaining a normal morphology in S. mutans and is required for its robust biofilm formation/interspecies competition. Therefore, EzrA protein represents a potential therapeutic target in the development of drugs controlling dental caries and other biofilm-related diseases.}, } @article {pmid31287831, year = {2019}, author = {Ryser, S and Tenorio, E and Estellés, A and Kauvar, LM}, title = {Human antibody repertoire frequently includes antibodies to a bacterial biofilm associated protein.}, journal = {PloS one}, volume = {14}, number = {7}, pages = {e0219256}, pmid = {31287831}, issn = {1932-6203}, mesh = {Adult ; Anti-Bacterial Agents/pharmacology ; Antibodies/analysis ; Antibodies, Monoclonal/immunology ; Antibodies, Monoclonal, Humanized/*immunology/metabolism/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Epitopes ; Female ; Healthy Volunteers ; Humans ; Male ; Single-Cell Analysis/methods ; }, abstract = {We have previously described a native human monoclonal antibody, TRL1068, that disrupts bacterial biofilms by extracting from the biofilm matrix key scaffolding proteins in the DNABII family, which are present in both gram positive and gram negative bacterial species. The antibiotic resistant sessile bacteria released from the biofilm then revert to the antibiotic sensitive planktonic state. Qualitative resensitization to antibiotics has been demonstrated in three rodent models of acute infections. We report here the surprising discovery that antibodies against the target family were found in all twenty healthy humans surveyed, albeit at a low level requiring a sensitive single B-cell assay for detection. We have cloned 21 such antibodies. Aside from TRL1068, only one (TRL1330) has all the biochemical properties believed necessary for pharmacological efficacy (broad spectrum epitope specificity and high affinity). We suggest that the other anti-DNABII antibodies, while not necessarily curative, reflect an immune response at some point in the donor's history to these components of biofilms. Such an immune response could reflect exposure to bacterial reservoirs that have been previously described in chronic non-healing wounds, periodontal disease, chronic obstructive pulmonary disease, colorectal cancer, rheumatoid arthritis, and atherosclerotic artery explants. The detection of anti-DNABII antibodies in all twenty surveyed donors with no active infection suggests that bacterial biofilm reservoirs may be present periodically in most healthy individuals. Biofilms routinely shed bacteria, creating a continuous low level inflammatory stimulus. Since chronic subclinical inflammation is thought to contribute to most aging-related diseases, suppression of bacterial biofilm has potential value in delaying age-related pathology.}, } @article {pmid31286367, year = {2019}, author = {Dong, QY and Wang, Z and Shi, LD and Lai, CY and Zhao, HP}, title = {Anaerobic methane oxidation coupled to chromate reduction in a methane-based membrane biofilm batch reactor.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {25}, pages = {26286-26292}, pmid = {31286367}, issn = {1614-7499}, support = {21577123, 51878596//National Natural Science Foundation of China/ ; LR17B070001//Natural Science Funds for Distinguished Young Scholar of Zhejiang Province/ ; }, mesh = {Anaerobiosis ; Biofilms ; Bioreactors/*microbiology ; Carbon Dioxide/metabolism ; Chromates/chemistry/*metabolism ; Methane/chemistry/*metabolism ; Methanobacterium/genetics/metabolism ; Methylomonas/genetics/metabolism ; Microbial Consortia/genetics/physiology ; Oxidation-Reduction ; Waste Disposal, Fluid/*instrumentation/methods ; }, abstract = {Chromate can be reduced by methanotrophs in a membrane biofilm reactor (MBfR). In this study, we cultivated a Cr(VI)-reducing biofilm in a methane (CH4)-based membrane biofilm batch reactor (MBBR) under anaerobic conditions. The Cr(VI) reduction rate increased to 0.28 mg/L day when the chromate concentration was ≤ 2.2 mg/L but declined sharply to 0.01 mg/L day when the Cr(VI) concentration increased to 6 mg/L. Isotope tracing experiments showed that part of the [13]C-labeled CH4 was transformed to [13]CO2, suggesting that the biofilm may reduce Cr(VI) by anaerobic methane oxidation (AnMO). Microbial community analysis showed that a methanogen, i.e., Methanobacterium, dominated in the biofilm, suggesting that this genus is probably capable of carrying out AnMO. The abundance of Methylomonas, an aerobic methanotroph, decreased significantly, while Meiothermus, a potential chromate-reducing bacterium, was enriched in the biofilm. Overall, the results showed that the anaerobic environment inhibited the activity of aerobic methanotrophs while promoting AnMO bacterial enrichment, and high Cr(VI) loading reduced Cr(VI) flux by inhibiting the methane oxidation process.}, } @article {pmid31286118, year = {2019}, author = {Menini, M and Setti, P and Dellepiane, E and Zunino, P and Pera, P and Pesce, P}, title = {Comparison of biofilm removal using glycine air polishing versus sodium bicarbonate air polishing or hand instrumentation on full-arch fixed implant rehabilitations: a split-mouth study.}, journal = {Quintessence international (Berlin, Germany : 1985)}, volume = {50}, number = {9}, pages = {722-730}, doi = {10.3290/j.qi.a42704}, pmid = {31286118}, issn = {1936-7163}, mesh = {Biofilms ; *Glycine ; Humans ; Mouth ; Periodontal Index ; Prostheses and Implants ; *Sodium Bicarbonate ; }, abstract = {OBJECTIVES: To compare the cleaning efficacy of glycine air polishing against two different professional oral hygiene techniques on implants supporting full-arch fixed prostheses.

METHOD AND MATERIALS: Thirty patients with a total of 32 implant fixed full-arch rehabilitations in the maxilla and/or mandible (134 implants) were included. After the removal of the screw-retained prostheses, baseline peri-implant spontaneous bleeding (SB), Plaque Index (PI), probing depth (PD), and bleeding on probing (BOP) were recorded (T0). Three oral hygiene treatments were assigned randomly following a split-mouth method: all the patients received glycine air polishing (G) in one side of the arch (n = 32), and sodium bicarbonate air polishing (B) (n = 16) or manual scaling with carbon-fiber curette (C) (n = 16) was performed in the opposite side. After the hygiene procedures, PI and SB were recorded and patient's comfort degree towards the three techniques was analyzed by questionnaires using a rating scale from 1 to 5 (T1).

RESULTS: PI reduction was significantly higher for G (T0, 2.88 ± 1.37; T1, 0.04 ± 0.21) and B (T0, 3.13 ± 1.34; T1, 0.0 ± 0.0) as compared with C (T0, 2.15 ± 1.46; T1, 0.44 ± 0.7) (P < .001). B reported the highest mean value of SB (T0, 0.0 ± 0.0; T1, 3.42 ± 0.75) compared with G (T0, 0.05 ± 0.21; T1, 1.60 ± 1.05) and C (T0, 0.07 ± 0.24; T1, 0.73 ± 0.91) (P < .001). A significant difference in comfort mean score was found between G (4.8 ± 0.5) and B (3.5 ± 1.7) (P = .014), no difference between G and C (4.7 ± 0.7) (P = .38).

CONCLUSION: Professional oral hygiene on implants using glycine air polishing showed high levels of both cleaning efficacy and patients' acceptance.}, } @article {pmid31284989, year = {2019}, author = {Barroso, I and Maia, V and Cabrita, P and Martínez-Suárez, JV and Brito, L}, title = {The benzalkonium chloride resistant or sensitive phenotype of Listeria monocytogenes planktonic cells did not dictate the susceptibility of its biofilm counterparts.}, journal = {Food research international (Ottawa, Ont.)}, volume = {123}, number = {}, pages = {373-382}, doi = {10.1016/j.foodres.2019.05.008}, pmid = {31284989}, issn = {1873-7145}, mesh = {Benzalkonium Compounds/*pharmacology ; Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Disinfectants/pharmacology ; Drug Resistance, Multiple, Bacterial ; Food Contamination ; Food Handling ; Food Microbiology ; Listeria monocytogenes/*drug effects/metabolism ; Microbial Sensitivity Tests ; Peracetic Acid/pharmacology ; Principal Component Analysis ; Stainless Steel ; }, abstract = {The main goal of this work was to approach food industry conditions in the comparison of the susceptibility of biofilms of Listeria monocytogenes to the biocides benzalkonium chloride (BAC) and peracetic acid (PAA). Twelve isolates of L. monocytogenes, including nine well characterized BAC resistant strains were used. Biofilms were produced on stainless steel coupons (SSC), at 11 °C (refrigeration temperature) or at 25 °C (room temperature), in culture media simulating clean (nutrient limiting) or soiled (nutrient rich) growth conditions. Neither different nutrient availability nor growth temperature showed significant effect (p > .05) on biofilm formation. PAA confirmed to be more effective than BAC in biofilm elimination. Biofilms formed under nutritional stress tended to differentiate more the response to BAC of the resistant or sensitive strains, but the resistant or sensitive phenotype of the planktonic cells did not dictate biofilm susceptibility.}, } @article {pmid31284975, year = {2019}, author = {Merino, L and Trejo, FM and De Antoni, G and Golowczyc, MA}, title = {Lactobacillus strains inhibit biofilm formation of Salmonella sp. isolates from poultry.}, journal = {Food research international (Ottawa, Ont.)}, volume = {123}, number = {}, pages = {258-265}, doi = {10.1016/j.foodres.2019.04.067}, pmid = {31284975}, issn = {1873-7145}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/growth & development ; Biological Control Agents/metabolism ; *Food Contamination ; *Food Microbiology ; Hydrocarbons/chemistry ; Hydrophobic and Hydrophilic Interactions ; Lactobacillus/classification/*metabolism ; Microscopy, Confocal ; Polystyrenes/chemistry ; Poultry/*microbiology ; Salmonella enteritidis/*isolation & purification/metabolism ; Salmonella typhimurium/*isolation & purification/metabolism ; Surface Properties ; }, abstract = {Lactic acid bacteria (LAB) exert a strong antagonistic activity against many microorganisms including food spoilage organisms and may be used as an alternative to control biofilm formation of pathogens in food industries. The objective of this work was to investigate the ability of fifteen Salmonella strains isolated from poultry environment to form biofilms on different surfaces. In addition, the effect of Lactobacillus kefiri strains 8321 and 83113 and Lactobacillus plantarum 83114 and their surface proteins on biofilm development of Salmonella Enteritidis 115 was studied. The relationship between surface properties of bacteria (hydrophobicity, autoaggregation and coaggregation with lactobacilli) and biofilm formation was also investigated. Most of Salmonella strains were hydrophilic and five strains were moderately hydrophobic. In general, Salmonella strains showed high aggregation abilities (27-54%). S. Enteritidis 106 and S. Typhimurium 102 and 108 showed the highest percentages of autoaggregation. All Salmonella strains tested showed aggregation abilities with the three lactobacilli studied, but the percentage of coaggregation proved to be strain-specific. When comparing stainless steel, glass and polystyrene surfaces, higher levels of biofilm formation occurred on polystyrene plate than on glass surfaces or stainless steel. S. Enteritidis 115 exhibited the greatest attachment to polyestyrene surface. The preincubation or coincubation with the three lactobacilli strains significantly reduced (about 1 log CFU/ml of reduction) the ability of S. Enteritidis 115 to form biofilm compared to the control without lactobacilli. These results were confirmed by confocal microscopy. In the same way, when surface proteins extracted from lactobacilli strains were preincubated or coincubated with S. Enteritidis 115, biofilm formation of this strain was significantly decreased compared to the control. The results obtained showed that these Lactobacillus strains and their surface proteins can be used as alternatives for control of biofilm formation by Salmonella in the poultry industry.}, } @article {pmid31284940, year = {2019}, author = {Rajkumari, J and Borkotoky, S and Reddy, D and Mohanty, SK and Kumavath, R and Murali, A and Suchiang, K and Busi, S}, title = {Anti-quorum sensing and anti-biofilm activity of 5-hydroxymethylfurfural against Pseudomonas aeruginosa PAO1: Insights from in vitro, in vivo and in silico studies.}, journal = {Microbiological research}, volume = {226}, number = {}, pages = {19-26}, doi = {10.1016/j.micres.2019.05.001}, pmid = {31284940}, issn = {1618-0623}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins ; Biofilms/*drug effects ; Caenorhabditis elegans ; Computer Simulation ; Disease Models, Animal ; Furaldehyde/*analogs & derivatives/pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/*pathogenicity ; Quorum Sensing/*drug effects/genetics ; Survival Rate ; Trans-Activators ; Virulence/drug effects ; Virulence Factors ; }, abstract = {Pseudomonas aeruginosa is one of the most common pathogens associated with nosocomial infections and a great concern to immunocompromised individuals especially in the cases of cystic fibrosis, AIDS and burn wounds. The pathogenicity of P. aeruginosa is largely directed by the quorum sensing (QS) system. Hence, QS may be considered an important therapeutic target to combat P. aeruginosa infections. The anti-quorum sensing and anti-biofilm efficacy of aromatic aldehyde, 5-hydroxymethylfurfural (5-HMF) against P. aeruginosa PAO1 were assessed. At the sub-inhibitory concentration, 5-HMF suppressed the production of QS-controlled virulence phenotypes and biofilm formation in P. aeruginosa. It was also able to significantly enhance the survival rate of C. elegans infected with P. aeruginosa. The in silico studies revealed that 5-HMF could serve as a competitive inhibitor for the auto-inducer molecules as it exhibited a strong affinity for the regulatory proteins of the QS-circuits i.e. LasR and RhlR. In addition, a significant down-regulation in the expression of QS-related genes was observed suggesting the ability of 5-HMF in mitigating the pathogenicity of P. aeruginosa.}, } @article {pmid31284905, year = {2019}, author = {Li, L and Yan, G and Wang, H and Chu, Z and Li, Z and Ling, Y and Wu, T}, title = {Denitrification and microbial community in MBBR using A. donax as carbon source and biofilm carriers for reverse osmosis concentrate treatment.}, journal = {Journal of environmental sciences (China)}, volume = {84}, number = {}, pages = {133-143}, doi = {10.1016/j.jes.2019.04.030}, pmid = {31284905}, issn = {1001-0742}, mesh = {Bioreactors/*microbiology ; *Denitrification ; *Microbial Consortia ; Nitrogen/*isolation & purification ; Poaceae/*chemistry/microbiology ; Water Purification ; }, abstract = {In this study, raw Arundo donax (A. donax) pieces were applied as carbon source and biofilm carriers for denitrification in a lab-scale moving bed biofilm reactor (MBBR) for the treatment of reverse osmosis concentrate gathered from local wastewater reuse plant. At stable phase (about 60 days), efficient denitrification performance was obtained with 73.2% ± 19.5% NO3[-]-N average removal and 8.10 ± 3.45 g N/(m[3]·day) NO3[-]-N average volumetric removal rate. Mass balance analysis showed that 4.84 g A. donax was required to remove 1 g TN. Quantitative real-time PCR analysis results showed that the copy numbers of 16S r-RNA, narG, nirS, nosZ and anammox gene of carrier biofilm and suspended activated sludge in the declination phase (BF2 and AS2) were lower than those of samples in the stable phase (BF1 and AS1), and relatively higher copy numbers of nirS and nirK genes with lower abundance of narG and nosZ genes were observed. High-throughput sequencing analysis was conducted for BF2 and AS2, and similar dominant phyla and classes with different abundance were obtained. The class Gammaproteobacteria affiliated with the phylum Proteobacteria was the most dominant microbial community in both BF2 (52.6%) and AS2 (41.7%). The PICRUSt prediction results indicated that 33 predictive specific genes were related to denitrification process, and the relative abundance of 18 predictive specific genes in BF2 were higher than those in AS2.}, } @article {pmid31284195, year = {2019}, author = {Lu, L and Wang, B and Zhang, Y and Xia, L and An, D and Li, H}, title = {Identification and nitrogen removal characteristics of Thauera sp. FDN-01 and application in sequencing batch biofilm reactor.}, journal = {The Science of the total environment}, volume = {690}, number = {}, pages = {61-69}, doi = {10.1016/j.scitotenv.2019.06.453}, pmid = {31284195}, issn = {1879-1026}, mesh = {Biofilms ; Bioreactors/*microbiology ; *Nitrogen ; Thauera/*metabolism ; Waste Disposal, Fluid/*methods ; }, abstract = {A strain FDN-01 was isolated from the sequencing batch biofilm reactor (SBBR) which was seeded with wasted activated sludge from a municipal wastewater treatment plant in Shanghai. Bacterium FDN-01 was identified as Thauera sp., and Genbank Sequence_ID was KY393097. By comparing inorganic total nitrogen (TN) removal efficiency by strain FDN-01 under different conditions, the optimal initial pH, carbon source and the ratio of carbon to nitrogen were 7.5, sodium succinate and 4.0, respectively. Inorganic TN removal efficiency was 93% within 3 d while the concentration of nitrate was 100 mg/L, and the type of substrates affected extracellular polymeric substances (EPS) production and the ratio of protein to polysaccharide in the EPS. Further investigation for the application of strain FDN-01 in the SBBRs showed that anoxic ammonia oxidation occurred at room temperature, and the removal efficiencies of inorganic TN were noticeably enhanced by the augmentation of bacterium FDN-01 back into the SBBR. This study provided a promising method of TN removal requiring less carbon source in the wastewater.}, } @article {pmid31284075, year = {2019}, author = {Carmello, JC and Alves, F and Basso, FG and de Souza Costa, CA and Tedesco, AC and Lucas Primo, F and Mima, EGO and Pavarina, AC}, title = {Antimicrobial photodynamic therapy reduces adhesion capacity and biofilm formation of Candida albicans from induced oral candidiasis in mice.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {402-407}, doi = {10.1016/j.pdpdt.2019.06.010}, pmid = {31284075}, issn = {1873-1597}, mesh = {Animals ; Antifungal Agents/therapeutic use ; Biofilms/*drug effects ; Candida albicans/drug effects ; Candidiasis, Oral/*drug therapy ; Emulsions ; Indoles/administration & dosage/*therapeutic use ; Mice ; Nanoparticles ; Nystatin/therapeutic use ; Organometallic Compounds/administration & dosage/*therapeutic use ; Photochemotherapy/*methods ; Photosensitizing Agents/*therapeutic use ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (aPDT) has been considered an alternative therapeutic modality for the treatment of Candida infections. However, most studies are focused mainly on microorganism's inactivation efficiency. Here, we evaluated the efficacy of aPDT mediated by chloro-aluminum phthalocyanine encapsulated in cationic nanoemulsions (ClAlP-NE) to treat oral candidiasis in vivo and its effect on the adhesion and biofilm formation of Candida albicans.

METHODS: For this, mice were immunosuppressed and inoculated with C. albicans to produce oral candidiasis. aPDT and Nystatin were applied for 5 successive sessions. Next, the microbiological evaluation was determined (CFU/ml) and the analyses of virulence factors (adhesion capacity and biofilm formation) were performed. Data were analyzed by Two-way ANOVA (α = 0.05).

RESULTS: aPDT was as effective as Nystatin reducing 1.4 and 2.0 log10 of the cell viability (p ≤ 0.0001), respectively. Both treatments reduced the adhesion capacity and biofilm formation of C. albicans (p ≤ 0.0001) CONCLUSION: : ClAlP-NE-mediated aPDT was effective in reducing the virulence factors of C. albicans and also to treat induced oral candidiasis in mice.}, } @article {pmid31283996, year = {2019}, author = {Palaniraj, S and Murugesan, R and Narayan, S}, title = {Chlorogenic acid- loaded calcium phosphate chitosan nanogel as biofilm degradative materials.}, journal = {The international journal of biochemistry & cell biology}, volume = {114}, number = {}, pages = {105566}, doi = {10.1016/j.biocel.2019.105566}, pmid = {31283996}, issn = {1878-5875}, mesh = {*Biocompatible Materials/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; *Calcium Phosphates/chemistry/pharmacology ; *Chlorogenic Acid/chemistry/pharmacology ; Klebsiella pneumoniae/*physiology ; Nanogels/*chemistry ; Staphylococcus aureus/*physiology ; }, abstract = {This work describes an effort to develop an antimicrobial agent (chlorogenic acid - CGA) loaded porous nanogel based on calcium phosphate-chitosan (CaPNP@Chi) nanogel with biofilm degradative properties and has potential applications in restorative dentistry. The nanogel was prepared by ionic gelation of calcium phosphate nanoparticles and chitosan in the ratio of 1.25: 1. Chlorogenic acid was loaded to the nanoparticles as an ethanolic solution and the encapsulation efficiency determined by chromatographic techniques. The particle size and morphology of CaPNP@Chi and CaPNP@Chi@CGA was determined by dynamic light scattering and scanning electron microscopic techniques. The minimum inhibitory concentration against S. aureus and K. pneumoniae was determined through the well diffusion method. The biofilm formation and biofilm decay were studied through staining assays. The toxicity, if any of the nanogel was assessed by MTT assay against HaCaT cells. All data were statistically analyzed. The composite had a CGA encapsulation efficiency of 70% and was thermally stable up to 124 °C. The zone of inhibition was found to be 18.7 mm ± 0.6 against S. aureus. CaPNP@Chi@CGA showed a 68% increase in biofilm degradation when compared with the untreated group. Results obtained in this study suggest that the positively charged nanogel interacted with the bacterial cell membrane and brought about the disruption of the cell membrane. Also, CaPNP@Chi@CGA was observed to be nontoxic up to 40 μg/mL to HaCaT cells. These results support the potential of CaPNP@Chi@CGA nanogel for biofilm degradation and its application as filling material in restorative dentistry.}, } @article {pmid31282384, year = {2019}, author = {Meroni, G and Zamarian, V and Prussiani, C and Bronzo, V and Lecchi, C and Martino, PA and Ceciliani, F}, title = {The bovine acute phase protein α1-acid glycoprotein (AGP) can disrupt Staphylococcus aureus biofilm.}, journal = {Veterinary microbiology}, volume = {235}, number = {}, pages = {93-100}, doi = {10.1016/j.vetmic.2019.06.007}, pmid = {31282384}, issn = {1873-2542}, mesh = {Animals ; *Biofilms ; Cattle ; Female ; Genes, Bacterial ; Genotype ; Milk/chemistry ; Orosomucoid/*metabolism ; Staphylococcal Infections/*veterinary ; Staphylococcus aureus/genetics/*pathogenicity ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus biofilm-related infections are of clinical concern due to the capability of bacterial colonies to adapt to a hostile environment. The present study investigated the capability of the acute phase protein alpha 1-acid glycoprotein (AGP) to a) disrupt already established S. aureus biofilm and b) interfere with the biofilm de novo production by using Microtiter Plate assay (MtP) on field strains isolated from infected quarters by assessing. The present study also investigated whether AGP could interfere with the expression of bacterial genes related to biofilm formation (icaA, icaD, icaB, and icaC) and adhesive virulence determinants (fnbA, fnbB, clfA, clfB, fib, ebps, eno) by quantitative real-time PCR (qPCR). The results provided the evidence that AGP could disrupt the biofilm structure only when it was already developed, but could not prevent the de novo biofilm formation. Moreover, AGP could interfere with the expression levels of genes involved in biofilm formation in a dose- and strain-dependent way, by upregulating, or downregulating, icaABC genes and fnbB, respectively. The results presented in this study provide new insights about the direct antibacterial activity of AGP in bovine milk. It remains to be demonstrated the molecular bases of AGP mechanism of action, in particular for what concerns the scarce capability to interact with the de novo formation of biofilm.}, } @article {pmid31282211, year = {2019}, author = {Wongkaewkhiaw, S and Taweechaisupapong, S and Anutrakunchai, C and Nazmi, K and Bolscher, JGM and Wongratanacheewin, S and Kanthawong, S}, title = {D-LL-31 in combination with ceftazidime synergistically enhances bactericidal activity and biofilm destruction in Burkholderia pseudomallei.}, journal = {Biofouling}, volume = {35}, number = {5}, pages = {573-584}, doi = {10.1080/08927014.2019.1632835}, pmid = {31282211}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Burkholderia pseudomallei/*drug effects/physiology ; Cathelicidins/*pharmacology ; Ceftazidime/*pharmacology ; Microbial Sensitivity Tests ; Peptides/*pharmacology ; }, abstract = {Melioidosis is a severe disease caused by Burkholderia pseudomallei. The biofilm of B. pseudomallei acquires resistance to several antibiotics and may be related to relapse in melioidosis patients. Here, the killing activity of antimicrobial peptides (LL-37, LL-31) and the D-enantiomers (D-LL-37, D-LL-31) in combination with ceftazidime (CAZ) against B. pseudomallei 1026b, H777 and a biofilm mutant M10, derived from H777 grown under biofilm-stimulating conditions was observed. Using static conditions, D-LL-31 exhibited the strongest killing activity against the three isolates in a dose-dependent manner. IC50 values for D-LL-31 ranged from 1 to 6 µM, for isolates M10, H777, and 1026b, respectively. Moreover, D-LL-31 combined with CAZ synergistically decreased the IC50 values of the peptide and antibiotic and caused also disruption of biofilms of B. pseudomallei 1026b under flow conditions. Thus a combination of D-LL-31 and CAZ may enhance the efficacy of the currently used antibiotic treatments against B. pseudomallei.}, } @article {pmid31282200, year = {2019}, author = {Maquera Huacho, PM and Rodriguez Herrero, E and Verspecht, T and Pauwels, M and Marcantonio, E and Palomari Spolidorio, DM and Teughels, W}, title = {Terpinen-4-ol and carvacrol affect multi-species biofilm composition.}, journal = {Biofouling}, volume = {35}, number = {5}, pages = {561-572}, doi = {10.1080/08927014.2019.1630386}, pmid = {31282200}, issn = {1029-2454}, mesh = {Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Cymenes ; Humans ; Monoterpenes/*pharmacology ; Terpenes/*pharmacology ; }, abstract = {The aim of this study was to investigate the cytotoxic activity and inhibitory effect of terpinen-4-ol (T4ol) and carvacrol against single- and multi-species biofilms. The toxicity of each compound was tested on oral keratinocytes and evaluated by XTT assay. Inhibition and eradication of single-species biofilms were analyzed by crystal violet assay and the effect on multi-species biofilm composition was evaluated by qPCR. T4ol and carvacrol did not affect the epithelial cell viability, in contrast to chlorhexidine, which showed a high cytotoxic effect. Inhibition and eradication of single-species biofilms treated with T4ol and carvacrol were observed. The same inhibitory effect was observed for multi-species biofilms, especially on periodontal pathogens. In conclusion, specific concentrations of T4ol and carvacrol without toxicity towards the epithelial cells reduced the numbers of periodontal pathogens in single- and multi-species biofilms.}, } @article {pmid31280338, year = {2019}, author = {Wang, X and Shen, X and Wang, Z and Kong, Y}, title = {Viscoelasticity variation in a biofilm-mediated Bacillus subtilis suspension induced by adding polyethylene glycol.}, journal = {European biophysics journal : EBJ}, volume = {48}, number = {7}, pages = {599-608}, pmid = {31280338}, issn = {1432-1017}, support = {11772047//National Natural Science Foundation of China/ ; 11620101001//Key international collaborating Project from National Natural Science Foundation of China/ ; }, mesh = {Bacillus subtilis/*drug effects/*physiology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Elasticity/*drug effects ; Molecular Weight ; Polyethylene Glycols/chemistry/*pharmacology ; Rheology ; Suspensions ; Viscosity/drug effects ; }, abstract = {Recent experiments show that synthetic polymers can influence the degree of microbial aggregation and the rheological properties of bacterial suspensions, the study of which can help us control biofilm formation. In this article, we add polyethylene glycol (PEG) with various molecular weights and concentrations into two types Bacillus subtilis cell cultures, Luria Broth (LB) and Minimal Salts glutamate glycerol (MSgg), respectively. We first observe cell clusters in cell suspensions with various concentrations of PEG, and measure cluster size in both static and dynamic fluid environments. We find that cells gather together into big clusters and most of the cells are arranged longitudinally; and the large cell clusters are divided into smaller aggregates under fluid shear. We then use a rheometer to measure the viscoelastic properties of various cell cultures, to represent the degree of aggregation of the bacterial suspensions. We find the storage modulus, the loss modulus and the viscosity of bacterial suspensions not only depend on the cell aggregation but also depend on the directionality of cellular motion.}, } @article {pmid31280150, year = {2019}, author = {Zakaria, BS and Lin, L and Dhar, BR}, title = {Shift of biofilm and suspended bacterial communities with changes in anode potential in a microbial electrolysis cell treating primary sludge.}, journal = {The Science of the total environment}, volume = {689}, number = {}, pages = {691-699}, doi = {10.1016/j.scitotenv.2019.06.519}, pmid = {31280150}, issn = {1879-1026}, mesh = {Bacteria/isolation & purification ; *Bacterial Physiological Phenomena ; *Biofilms ; Electrodes ; Electrolysis ; Microbiota/*physiology ; Sewage/*microbiology ; Waste Disposal, Fluid/*methods ; }, abstract = {This study, for the first time, documented microbial community shifts in response to the changes in anode potential in a microbial electrolysis cell (MEC) operated with primary sludge. At an anode potential of -0.4 V vs. Ag/AgCl, the MEC showed COD and VSS removal efficiencies of 73 ± 1% and 75 ± 2%, respectively. The volumetric current density and specific hydrogen production rate were 23 ± 1.2 A/m[3], and 145 ± 4.1 L/m[3]-d, respectively. The anodic microbial community was consisted of various fermentative/hydrolytic bacteria (e.g., Bacteroides and Dysgonomonas) and anode-respiring bacteria (Geobacter), while different hydrolytic/fermentative bacteria were abundant in suspension. The MEC showed substantially inferior performance along with a higher accumulation of various volatile fatty acids when the anode potential was switched to more positive values (0 V and +0.4 V). Both biofilms and suspended communities were also shifted when the anode potential was changed. Notably, at +0.4 V, Geobacter genus entirely disappeared from the biofilms, while Paludibacter species (known fermentative bacteria) were selectively enriched in biofilms. Also, the relative abundance of genus Bacteroides (known hydrolytic bacteria) substantially decreased in both biofilms and suspension, which was correlated with the inferior hydrolysis of VSS. Quantitative comparison of biofilms and suspended microbial communities at different anode potentials revealed a sharp decrease in bacterial cell numbers in anode biofilms after changing anode potential from -0.4 V to +0.4 V. By contrast, bacterial cell numbers in suspension were slightly decreased. Collectively, these results provide new insights into the role of anode potential in shaping key microbial players associated with hydrolysis/fermentation and anodic respiration processes when MECs are operated with real biowastes.}, } @article {pmid31279761, year = {2019}, author = {Parvin, F and Hu, H and Whiteley, GS and Glasbey, T and Vickery, K}, title = {Difficulty in removing biofilm from dry surfaces.}, journal = {The Journal of hospital infection}, volume = {103}, number = {4}, pages = {465-467}, doi = {10.1016/j.jhin.2019.07.005}, pmid = {31279761}, issn = {1532-2939}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Disinfection/*methods ; *Environmental Microbiology ; Staphylococcus aureus/*growth & development ; }, abstract = {Cleaning is fundamental to infection control. This report demonstrates that a Staphylococcus aureus biofilm is significantly more difficult to remove than dried planktonic bacteria. A single wiping action removed >99.9% (>3 log10) of dried planktonic bacteria, whereas only 1.4 log10 of biofilm (96.66%) was removed by 50 wiping actions with a standardized wiping process.}, } @article {pmid31279340, year = {2019}, author = {Velsko, IM and Fellows Yates, JA and Aron, F and Hagan, RW and Frantz, LAF and Loe, L and Martinez, JBR and Chaves, E and Gosden, C and Larson, G and Warinner, C}, title = {Microbial differences between dental plaque and historic dental calculus are related to oral biofilm maturation stage.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {102}, pmid = {31279340}, issn = {2049-2618}, mesh = {Bacteria/*classification ; *Bacterial Physiological Phenomena ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Bone and Bones/microbiology ; DNA, Ancient/analysis ; DNA, Bacterial/genetics ; Dental Calculus/history/*microbiology ; Dental Plaque/*microbiology ; Female ; History, Ancient ; Humans ; Male ; Metagenomics ; Microbiota/*physiology ; Periodontal Diseases/microbiology ; Proteomics ; Tooth/*microbiology ; }, abstract = {BACKGROUND: Dental calculus, calcified oral plaque biofilm, contains microbial and host biomolecules that can be used to study historic microbiome communities and host responses. Dental calculus does not typically accumulate as much today as historically, and clinical oral microbiome research studies focus primarily on living dental plaque biofilm. However, plaque and calculus reflect different conditions of the oral biofilm, and the differences in microbial characteristics between the sample types have not yet been systematically explored. Here, we compare the microbial profiles of modern dental plaque, modern dental calculus, and historic dental calculus to establish expected differences between these substrates.

RESULTS: Metagenomic data was generated from modern and historic calculus samples, and dental plaque metagenomic data was downloaded from the Human Microbiome Project. Microbial composition and functional profile were assessed. Metaproteomic data was obtained from a subset of historic calculus samples. Comparisons between microbial, protein, and metabolomic profiles revealed distinct taxonomic and metabolic functional profiles between plaque, modern calculus, and historic calculus, but not between calculus collected from healthy teeth and periodontal disease-affected teeth. Species co-exclusion was related to biofilm environment. Proteomic profiling revealed that healthy tooth samples contain low levels of bacterial virulence proteins and a robust innate immune response. Correlations between proteomic and metabolomic profiles suggest co-preservation of bacterial lipid membranes and membrane-associated proteins.

CONCLUSIONS: Overall, we find that there are systematic microbial differences between plaque and calculus related to biofilm physiology, and recognizing these differences is important for accurate data interpretation in studies comparing dental plaque and calculus.}, } @article {pmid31279321, year = {2019}, author = {Shi, J and Han, Y and Xu, C and Han, H}, title = {Enhanced biodegradation of coal gasification wastewater with anaerobic biofilm on polyurethane (PU), powdered activated carbon (PAC), and biochar.}, journal = {Bioresource technology}, volume = {289}, number = {}, pages = {121487}, doi = {10.1016/j.biortech.2019.121487}, pmid = {31279321}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; Charcoal ; *Coal ; Polyurethanes ; Powders ; *Wastewater ; }, abstract = {The primary objective was to explore the feasibility of anaerobic biofilm on polyurethane (PU), powdered activated carbon (PAC), and biochar in strengthening anaerobic degradation of phenolic compounds and selected nitrogen heterocyclic compounds (NHCs) in coal gasification wastewater (CGW). When total phenols (TPh) was less than 300 mg/L, PAC-based biofilm was more efficient. Whereas, when the TPh concentration was more than 450 mg/L, PU-based biofilm performed the optimal degradation efficiency. Furthermore, microbial community structure analysis showed that PAC and biochar had little effect on the microbial community structure after 120 days of operation, while the addition of PU could lead to the enrichment of Giesbergeria, Caldisericum, Thauera, Methanolinea, and Methanoregula.}, } @article {pmid31279316, year = {2019}, author = {Cui, YX and Guo, G and Ekama, GA and Deng, YF and Chui, HK and Chen, GH and Wu, D}, title = {Elucidating the biofilm properties and biokinetics of a sulfur-oxidizing moving-bed biofilm for mainstream nitrogen removal.}, journal = {Water research}, volume = {162}, number = {}, pages = {246-257}, doi = {10.1016/j.watres.2019.02.061}, pmid = {31279316}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Kinetics ; *Nitrogen ; Oxidation-Reduction ; Sulfides ; Sulfur ; Wastewater ; }, abstract = {The sulfide-oxidizing autotrophic denitrification (SOAD) process offers a feasible alternative to mainstream heterotrophic denitrification in treating domestic sewage with insufficient organics. Previously SOAD has been successfully applied in a moving-bed biofilm reactor (MBBR). However, the biofilm properties and biokinetics are still not thoroughly understood. The present study was therefore designed to investigate these features of sulfur-oxidizing biofilms (SOBfs) cultivated in a lab-scale MBBR under stable operation for over a year. The biofilms developed were 160 μm thick, had an uneven and porous surface on which elemental sulfur (S[0]) accumulated, and the SOB biomass was highly diverse. The bioprocess kinetics were evaluated through 12 batch experiments. The results were interpreted by adopting a two-step sulfide oxidation model (sulfide→S[0] and S[0]→ sulfate) with all specific rates having a linear regression coefficient of R[2] > 0.9. Moreover, the inhibitory kinetic analysis revealed that 1) the maximum treatment capacity (about 480 mg S/(m[2]·h) and 80 mg N/(m[2]·h)) was observed at low sulfide level (40 mg S/L), while higher sulfide level (60-150 mg S/L) showed increasing inhibition on the oxidation of both sulfide and sulfur and denitrification. 2) The denitritation activity decreased by up to 43% when free nitrous acid reached a maximum of 8.6 μg N/L, whereas the oxidation of sulfide and sulfur did not have any significant effect. Interestingly, two physiologically diverse SOB groups were found in this special biofilm. The mechanisms of the cooperation and competition for electron donors and acceptors between these two SOB clades are proposed. The results of this study greatly enhance our understanding of the design and optimization of SOAD-MBBR for mainstream nitrogen removal.}, } @article {pmid31278701, year = {2019}, author = {Liaqat, I and Liaqat, M and Tahir, HM and Haq, I and Ali, NM and Arshad, M and Arshad, N}, title = {Motility effects biofilm formation in Pseudomonas aeruginosa and Enterobacter cloacae.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {32}, number = {3}, pages = {927-932}, pmid = {31278701}, issn = {1011-601X}, mesh = {Biofilms/*growth & development ; Enterobacter cloacae/cytology/genetics/*physiology ; Flagella/*physiology ; Hydrogen-Ion Concentration ; Pseudomonas aeruginosa/cytology/genetics/*physiology ; RNA, Ribosomal, 16S ; Temperature ; Time Factors ; }, abstract = {Chronic infections caused by gram negative bacteria are the mains reasons to have morbidity and death in patients, despite using high doses of antibiotics applied to cure diseases producing by them. This study was designed to identify the role of flagella in biofilm formation Ten pure strains were collected from our lab. Morphological variation and motility assays led us to study two strains in detail. They were characterized biochemically, physiologically and genetically. Biofilm formation analysis was performed using test tube assay, congo red assay and liquid-interface coverslip assay. In order to disrupt flagella of studied strains, blending was induced for 5, 10 and 15 minutes followed by centrifugation and observing motility using motility test. Biofilm quantification of wild type (parental) and blended strains was done using test tube and liquid interface coverslip assays. 16S rRNA sequencing identified strains as Pseudomonas aeroginosa and Enterobacter cloacae. Significant biofilm formation (p>0.05) by was observed after 72 and 18 hours using test tube and liquid-interface coverslip assays respectively. Flagellar disruption showed that 15 minutes blending caused significant reduction in both strains, hence demonstrated that flagellar mediated motility could be a potent strategy to stabilize aggregate and invest resources for biofilm formation in P. aeruginosa and E. cloacae.}, } @article {pmid31278369, year = {2019}, author = {Hou, J and Wang, C and Rozenbaum, RT and Gusnaniar, N and de Jong, ED and Woudstra, W and Geertsema-Doornbusch, GI and Atema-Smit, J and Sjollema, J and Ren, Y and Busscher, HJ and van der Mei, HC}, title = {Bacterial Density and Biofilm Structure Determined by Optical Coherence Tomography.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {9794}, pmid = {31278369}, issn = {2045-2322}, mesh = {Algorithms ; Bacteria/*growth & development ; *Biofilms/growth & development ; Models, Theoretical ; *Tomography, Optical Coherence ; }, abstract = {Optical-coherence-tomography (OCT) is a non-destructive tool for biofilm imaging, not requiring staining, and used to measure biofilm thickness and putative comparison of biofilm structure based on signal intensity distributions in OCT-images. Quantitative comparison of biofilm signal intensities in OCT-images, is difficult due to the auto-scaling applied in OCT-instruments to ensure optimal quality of individual images. Here, we developed a method to eliminate the influence of auto-scaling in order to allow quantitative comparison of biofilm densities in different images. Auto- and re-scaled signal intensities could be qualitatively interpreted in line with biofilm characteristics for single and multi-species biofilms of different strains and species (cocci and rod-shaped organisms), demonstrating qualitative validity of auto- and re-scaling analyses. However, specific features of pseudomonas and oral multi-species biofilms were more prominently expressed after re-scaling. Quantitative validation was obtained by relating average auto- and re-scaled signal intensities across biofilm images with volumetric-bacterial-densities in biofilms, independently obtained using enumeration of bacterial numbers per unit biofilm volume. The signal intensities in auto-scaled biofilm images did not significantly relate with volumetric-bacterial-densities, whereas re-scaled intensities in images of biofilms of widely different strains and species increased linearly with independently determined volumetric-bacterial-densities in the biofilms. Herewith, the proposed re-scaling of signal intensity distributions in OCT-images significantly enhances the possibilities of biofilm imaging using OCT.}, } @article {pmid31277901, year = {2019}, author = {Cameron, R and Claudia, E and Ping, W and Erin, S and Ruparel, NB}, title = {Effect of a Residual Biofilm on Release of Transforming Growth Factor β1 from Dentin.}, journal = {Journal of endodontics}, volume = {45}, number = {9}, pages = {1119-1125}, doi = {10.1016/j.joen.2019.05.004}, pmid = {31277901}, issn = {1878-3554}, mesh = {*Biofilms ; Calcium Hydroxide/pharmacology ; Dental Pulp Cavity ; *Dentin/metabolism ; Humans ; *Root Canal Irrigants ; *Transforming Growth Factor beta1/drug effects/metabolism ; }, abstract = {INTRODUCTION: Several studies have reported regeneration of the pulp-dentin complex when treating noninfected root canal systems. However, current protocols applied to infected root canal systems are much less predictable for the formation of dentin. Converging lines of evidence implicate residual biofilm as an important factor for these variable histologic outcomes. Here we studied the effect of a residual polymicrobial biofilm on the release of transforming growth factor beta 1 (TGF-β1) from dentin. We hypothesized that the presence of bacterial biofilm attenuates the release of bioactive molecules from dentin.

METHODS: Using bacteria commonly found in infected immature teeth, we developed a multispecies biofilm in an organotypic root canal model. Root segments were then subjected to various irrigation or intracanal medicament protocols. Subsequently, the release of TGF-β1 from dentin was measured using the enzyme-linked immunosorbent assay.

RESULTS: Our data show that sterile root segments released greater amounts of TGF-β1 when conditioned with 17% EDTA alone (P < .001) or with the combination of 1.5% sodium hypochlorite and 17% EDTA (P < .05) compared with root segments infected with the multispecies biofilm. Similar results were also observed with the intracanal medicament protocol. Sterile root segments medicated with various concentrations of triple antibiotic paste and full-strength calcium hydroxide released greater amounts of TGF-β1 when compared with their infected counterparts.

CONCLUSIONS: This is the first study to report the detrimental effects of a residual biofilm on dentin conditioning and, therefore, the release of growth factors critical for regenerative procedures.}, } @article {pmid31276938, year = {2019}, author = {Huang, Y and Thompson, T and Wang, Y and Yu, Q and Zhu, L and Xu, X and Wen, ZT and Townsend, JA}, title = {Analysis of cariogenic potential of alternative milk beverages by in vitro Streptococcus mutans biofilm model and ex vivo caries model.}, journal = {Archives of oral biology}, volume = {105}, number = {}, pages = {52-58}, pmid = {31276938}, issn = {1879-1506}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; R01 DE026782/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Dental Caries/*etiology ; In Vitro Techniques ; *Milk Substitutes ; Streptococcus mutans/*pathogenicity ; Sucrose ; *Tooth Demineralization ; }, abstract = {OBJECTIVE: To evaluate the potential of various alternative milk beverages to support bacterial biofilm formation and acid production and cause unbalanced demineralization.

DESIGN: in vitro assays were used to examine the ability of the beverages to support Streptococcus mutans' biofilm formation and acid production from sugar fermentation and the capacity of the beverages to buffer pH changes. Biofilm formation was done using 96-well plate model. Acid production was measured using L-Lactate assay kit, and the buffering capacity was assessed by pH titration. For ex vivo caries model, enamel and dentine slabs and S. mutans biofilms were exposed to selected alternative milk beverages three times a day, 30 min each, and by the end of the experiments, slab's demineralization was assessed by loss of surface microhardness.

RESULTS: Of the alternative milk beverages tested in this study, Original Almond consistently supported the most S. mutans biofilms, followed by Chocolate Cashew Milk, while the least biofilms were measured with Unsweetened Flax Milk. The most acids and the lowest culture pH were measured with Toasted Coconut Almond Milk, while the least buffering capacity was measured with Unsweetened Coconut Milk. The results of ex vivo caries model showed that like Bovine Whole Milk, repeated exposure to Original Almond led to significant enamel and dentine slab demineralization, when compared to those exposed to saline as a control (P < 0.001).

CONCLUSIONS: These results further provide support that popular alternative milk beverages, especially those with supplemental sugars, are potentially cariogenic.}, } @article {pmid31275531, year = {2019}, author = {Schoilew, K and Ueffing, H and Dalpke, A and Wolff, B and Frese, C and Wolff, D and Boutin, S}, title = {Bacterial biofilm composition in healthy subjects with and without caries experience.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1633194}, pmid = {31275531}, issn = {2000-2297}, abstract = {Objective:The composition of the oral microbiome differs distinctively between subjects with and without active caries. Still, caries research has mainly been focused on states of disease; aspects about how biofilm composition and structure maintain oral health still remain widely unclear. Therefore, the aim of the study was to compare the healthy oral microbiome of caries-free adult subjects with and without former caries experience using next generation sequencing methods. Methods: 46 samples were collected from subjects without any signs of untreated active caries. Samples of pooled supragingival plaque from 19 subjects without caries experience (NH; DMFT = 0) and 27 subjects with 'caries experience' (CE; DMFT > 0 [F(T)> 0; D(T)= 0]) were analyzed by 16S ribosomal RNA amplicon sequencing. Results: Subjects with caries experience did not exhibit a dramatically modified supragingival plaque microbiome. However, we observed a slight and significant modification between the two groups, validated by PERMANOVA (NH vs. CE: R2 0.04; p= 0.039). The composition of the microbiome of subjects with caries experience indicates a tendency to lower α-diversity and richness. Subjects without caries experience showed a significant higher evenness compared to patients with previous caries. LDA effect size (LEfSe) analysis demonstrated that the genus Haemophilus is significantly more frequent in patients with caries experience. For the group without caries experience LefSe analysis showed a set of 11 genera being significantly more frequent, including Corynebacterium, Fusobacterium, Capnocytophaga, Porphyromonas, Prevotella,and Leptotrichia. Conclusion: The analysis of the oral microbiome of subjects with and without caries experience indicates specific differences. With the presence of Corynebacterium and Fusobacterium subjects without caries experience exhibited more frequently organisms that are considered to be main actors in structural plaque formation and integration. The abundance of Corynebacterium might be interpreted as a signature for dental health.}, } @article {pmid31275529, year = {2019}, author = {Shany-Kdoshim, S and Polak, D and Houri-Haddad, Y and Feuerstein, O}, title = {Killing mechanism of bacteria within multi-species biofilm by blue light.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1628577}, pmid = {31275529}, issn = {2000-2297}, abstract = {Objectives: The aim of the study was to characterize the immediate and delayed effects of non-coherent blue-light treatment on the composition and viability of an in vitro biofilm composed of anaerobic multispecies, as well as the mechanisms involved. Methods: A multispecies biofilm was constructed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis and Fusobacterium nucleatum, test groups were exposed to blue light. The multispecies biofilm was explored with a newly developed method based on flow cytometry and confocal microscopy. The involvement of the paracrine pathway in the phototoxic mechanism was investigated by a crossover of the supernatants between mono-species P. gingivalis and F. nucleatum biofilms. Results: Blue light led to a reduction of about 50% in the viable pathogenic bacteria P. gingivalis and F. nucleatum, vs that in the non-exposed biofilm. Biofilm thickness was also reduced by 50%. The phototoxic effect of blue light on mono-species biofilm was observed in P. gingivalis, whereas F. nucleatum biofilm was unaffected. A lethal effect was obtained when the supernatant of P. gingivalis biofilm previously exposed to blue light was added to the F. nucleatum biofilm. The effect was circumvented by the addition of reactive oxygen species (ROS) scavengers to the supernatant. Conclusion: Blue-light has an impact on the bacterial composition and viability of the multispecies biofilm. The phototoxic effect of blue light on P. gingivalis in biofilm was induced directly and on F. nucleatum via ROS mediators of the paracrine pathway. This phenomenon may lead to a novel approach for 'replacement therapy,' resulting in a less periodonto-pathogenic biofilm.}, } @article {pmid31275267, year = {2019}, author = {Zhu, YL and Hou, HM and Zhang, GL and Wang, YF and Hao, HS}, title = {AHLs Regulate Biofilm Formation and Swimming Motility of Hafnia alvei H4.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1330}, pmid = {31275267}, issn = {1664-302X}, abstract = {The aim of this study was to evaluate the role of N-acyl homoserine lactones (AHLs) in the regulation of swimming motility of Hafnia alvei H4 and its biofilm formation on 96-well plate, glass and stainless-steel surfaces. The luxI gene, which codes for an enzyme involved in AHL synthesis, was deleted to generate a luxI mutant (ΔluxI). The mutant produced no AHL, and the relative expression of the luxR gene was significantly (P < 0.05) decreased. In addition, qRT-PCR analysis showed that the relative expression of the luxR gene in ΔluxI was stimulated by the presence of exogenous AHLs (C4-HSL, C6-HSL, and 3-o-C8-HSL) added at concentrations ranging from of 50-250 μg/ml. Among the three AHLs, C6-HSL had the strongest effect. The ability of ΔluxI to form biofilm on 96-well plate, glass and stainless-steel surfaces was significantly reduced (P < 0.05) compared with the wild type (WT), but was increased when provided with 150 μg/ml C4-HSL, whereas C6-HSL and 3-o-C8-HSL had no effect. Scanning electron microscopy analysis of the biofilm revealed less bacteria adhering to the surface of stainless-steel and fewer filaments were found binding to the cells compared with the WT. Furthermore, ΔluxI also exhibited significant (P < 0.05) decrease in the expression of biofilm- and swimming motility-related genes, flgA, motA and cheA, consistent with the results observed for biofilm formation and swimming motility. Taken together, the results suggested that in H. alvei H4, C4-HSL may act as an important molecular signal through regulating the ability of the cells to form biofilm, as well as through regulating the swimming motility of the cell, and this could provide a new way to control these phenotypes of H. alvei in food processing.}, } @article {pmid31273528, year = {2020}, author = {Hasegawa, T and Takenaka, S and Ohsumi, T and Ida, T and Ohshima, H and Terao, Y and Naksagoon, T and Maeda, T and Noiri, Y}, title = {Effect of a novel glass ionomer cement containing fluoro-zinc-silicate fillers on biofilm formation and dentin ion incorporation.}, journal = {Clinical oral investigations}, volume = {24}, number = {2}, pages = {963-970}, pmid = {31273528}, issn = {1436-3771}, support = {15H05021//Japan Society for the Promotion of Science/ ; None//GC Corporation/ ; }, mesh = {*Biofilms ; Dentin ; *Glass Ionomer Cements ; Humans ; Materials Testing ; Silicates ; *Zinc ; }, abstract = {OBJECTIVES: This study is aimed at evaluating the effect of a new glass ionomer cement (GIC) containing fluoro-zinc-silicate fillers on biofilm formation and ion incorporation.

MATERIALS AND METHODS: Streptococcus mutans biofilms were developed on two GIC materials: Caredyne Restore (CD) and Fuji VII (FJ); and hydroxyapatite (HA) for 24 h at 37 °C using a flow cell system. The morphological structure and bacterial viability were analyzed using a confocal laser scanning microscopy. Bacterial adhesion during the initial 2 h was also assessed by viable cell counting. To study the ion incorporation, restored cavities prepared on the root surfaces of human incisors were subjected to the elemental mapping of the zinc and fluoride ions in the GIC-dentin interface using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer.

RESULTS: Morphological observations revealed that biofilm formation in the CD group was remarkably inhibited compared with the HA and FJ groups, exhibiting sparse, thinner biofilm clusters. The microorganisms adhering to the CD group were significantly inhibited, revealing 2.9 ± 0.4 for CD, 4.9 ± 0.2 for FJ, and 5.4 ± 0.4 log colony-forming units (CFU) for HA. The CD zinc ion incorporation depth was 72.2 ± 8.0 μm. The fluoride penetration of CD was three times deeper than that of FJ; this difference was statistically significant (p < 0.05).

CONCLUSIONS: Enhanced by the incorporation of zinc and fluoride ions, the new GIC inhibited biofilm formation by interfering with bacterial adhesion.

CLINICAL RELEVANCE: A novel GIC comprised of fluoro-zinc-silicate fillers may improve clinical outcomes, such as root caries and minimally invasive dentistry.}, } @article {pmid31272369, year = {2019}, author = {Cai, W and De La Fuente, L and Arias, CR}, title = {Transcriptome analysis of the fish pathogen Flavobacterium columnare in biofilm suggests calcium role in pathogenesis.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {151}, pmid = {31272369}, issn = {1471-2180}, mesh = {Animals ; Bacterial Adhesion/genetics ; Biofilms/*growth & development ; Calcium/*metabolism ; Fish Diseases/microbiology ; Fishes/*microbiology ; *Flavobacterium/genetics/growth & development ; Gene Expression Profiling ; Iron/metabolism ; Oxidative Stress/genetics ; Transcriptome/genetics ; Virulence Factors/genetics/metabolism ; }, abstract = {BACKGROUND: Flavobacterium columnare is the causative agent of columnaris disease that affects cultured freshwater fishes worldwide. F. columnare easily colonizes surfaces by forming biofilm, which helps the pathogen resist antibiotic and disinfectant treatments. Previously, we had shown that increasing concentrations of calcium (Ca[2+]) promoted biofilm formation by F. columnare. The objective of this study was to further characterize the role of Ca[2+] on biofilm formation and to compare the transcriptome profiles of planktonic and biofilm cells.

RESULTS: RNA-Seq analysis was conducted to identify genes that were differentially expressed between the following states: i) planktonic cells in control medium (P), ii) planktonic cells in calcium-enriched medium (P/Ca), and iii) biofilm cells in calcium-enriched medium (B/Ca). Overall, we identified 441 significant (FDR-adjusted p < 0.05, fold change > 2) differentially expressed genes (DEGs) between P and B/Ca samples; 112 significant DEGs between P/Ca and B/Ca samples, and 175 significant DEGs between P/Ca and P samples, corresponding to 15.87, 4.03 and 6.30% of the total protein-coding sequences, respectively. The significant DEGs fell into different functional categories including iron acquisition, oxidative stress response, extracellular protein secretion, and respiratory metabolism.

CONCLUSIONS: Our results posit Ca[2+] as a critical signal in regulating bacterial surface adhesion and biofilm formation in F. columnare. Living in biofilm elicited a shift in several metabolic pathways that allowed the cells to cope with oxidative stress and nutrient starvation. In addition, Ca[2+] supplementation induced the expression of putative virulence factors in F. columnare, such as extracellular protein secretion and iron acquisition.}, } @article {pmid31271350, year = {2019}, author = {Romera, D and Aguilera-Correa, JJ and Gadea, I and Viñuela-Sandoval, L and García-Rodríguez, J and Esteban, J}, title = {Candida auris: a comparison between planktonic and biofilm susceptibility to antifungal drugs.}, journal = {Journal of medical microbiology}, volume = {68}, number = {9}, pages = {1353-1358}, doi = {10.1099/jmm.0.001036}, pmid = {31271350}, issn = {1473-5644}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/isolation & purification ; Candida albicans/drug effects ; Candida parapsilosis/drug effects ; Candidiasis/microbiology ; Colony Count, Microbial ; Drug Resistance, Fungal ; Echinocandins/pharmacology ; Fluconazole/pharmacology ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Polyenes/pharmacology ; }, abstract = {Introduction. Candida auris is a pathogenic yeast that mainly affects immunosuppressed patients and those with implanted medical devices. This pathogen also displays elevated resistance to common antifungals and high survival and spreading capacities. Since no antifungal breakpoints have yet been defined for this pathogen, the data obtained here can be useful for further research concerning treatment or implementation of a prevention and disinfection protocol. Our aim was to study the antifungal resistance of C. auris to current antifungals in planktonic and sessile states. Using confocal laser scanning microscopy and viable biomass production, we demonstrated the ability of C. auris to develop a mature biofilm. We compared the minimal inhibitory concentration (MIC) and the minimal biofilm eradication concentration (MBEC) for the C. auris DSM 21092 strain plus two clinical isolates, and the results were compared with those obtained for Candida albicans and Candida parapsilosis, two species strongly linked to bloodstream infections and infections associated with biomaterials. We found that the clinical isolates of C. auris were resistant to fluconazole and sensitive to echinocandins and polyenes. The C. auris biofilms did not show susceptibility to any antifungal agent, showing MBECs that were up to 512-fold higher than the MICs. These findings highlight the importance of biofilm formation as a key factor underlying the resistance of this species to antifungals and suggest that the presence of implantable medical devices is one of the major risk factors in immunocompromised patients.}, } @article {pmid31271299, year = {2019}, author = {Pereira-Ribeiro, PM and Sued-Karam, BR and Faria, YV and Nogueira, BA and Colodette, SS and Fracalanzza, SE and Duarte, JL and Júnior, RH and Mattos-Guaraldi, AL}, title = {Influence of antibiotics on biofilm formation by different clones of nosocomial Staphylococcus haemolyticus.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {789-799}, doi = {10.2217/fmb-2018-0230}, pmid = {31271299}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteremia/microbiology ; Biofilms/*drug effects/*growth & development ; Electrophoresis, Gel, Pulsed-Field ; Genes, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Molecular Typing ; Polymerase Chain Reaction ; Staphylococcal Infections/microbiology ; Staphylococcus haemolyticus/classification/*drug effects/*growth & development/isolation & purification ; }, abstract = {Staphylococcus haemolyticus is the most common organism among clinical isolatesof methicillin-resistant staphylococci. Aim: This study evaluated the ability to produce biofilm with the presence of the antibiotics (1/4 minimum inhibitory concentrations) of S. haemolyticus strains isolated from blood culture. Methods: Clonal distribution was assessed in pulsed-field gel electrophoresis. PCR assays were performed to detect mecA, icaA, aap, atlE, atl, fbp genes. S. haemolyticus strains grown in the presence of the antibiotics were investigated for biofilm formation on glass, polystyrene and catheter surfaces. Results: Biofilm formation was independent of the presence of the icaA and mecA genes, pulsed-field gel electrophoresis type. Vancomycin, oxacillin, moxifloxacin, rifampicin, teicoplanin, tigecycline and linezolid did not inhibit biofilm formation on abiotic surfaces. Conclusion: This study demonstrated that the biofilm formation process is complex and may not be related to ica gene carriage. Furthermore, in this study the biofilm formation was increased in the presence of antimicrobial agents.}, } @article {pmid31269803, year = {2019}, author = {Yang, X and Zhang, Z and Huang, Z and Zhang, X and Li, D and Sun, L and You, J and Pan, X and Yang, H}, title = {A putative LysR-type transcriptional regulator inhibits biofilm synthesis in Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {35}, number = {5}, pages = {541-550}, doi = {10.1080/08927014.2019.1627337}, pmid = {31269803}, issn = {1029-2454}, mesh = {Alginates/metabolism ; Bacterial Proteins/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Polysaccharides, Bacterial/biosynthesis ; Pseudomonas aeruginosa/*physiology ; Transcription Factors/*metabolism ; }, abstract = {Biofilm formation is an important virulence factor which is controlled by complex regulatory circuits in Pseudomonas aeruginosa. In this work, a biofilm hyper-producing strain, P2-7, was selected from a collection of transposon insertion mutants in which the PA2121 gene was disrupted. PA2121 was predicted as a putative LysR-type regulator. Analyses showed that it was involved in early biofilm formation, mature biofilm development, and colony morphology. Quantitative measurements revealed that PA2121 repressed biosynthesis of extracellular polysaccharides (alginate, psl and pel). Furthermore, it was observed that PA2121 was self-regulated, highly expressed in the early phase of biofilm development, and subject to the negative regulation by a biofilm synthesis regulator SrpA that binds directly to the PA2121 gene promoter. Collectively, this study proposes that PA2121 is a novel biofilm synthesis repressor (BsrA) in P. aeruginosa.}, } @article {pmid31268675, year = {2019}, author = {Blanco-Cabra, N and Vega-Granados, K and Moya-Andérico, L and Vukomanovic, M and Parra, A and Álvarez de Cienfuegos, L and Torrents, E}, title = {Novel Oleanolic and Maslinic Acid Derivatives as a Promising Treatment against Bacterial Biofilm in Nosocomial Infections: An in Vitro and in Vivo Study.}, journal = {ACS infectious diseases}, volume = {5}, number = {9}, pages = {1581-1589}, doi = {10.1021/acsinfecdis.9b00125}, pmid = {31268675}, issn = {2373-8227}, mesh = {Animals ; Bacterial Outer Membrane/drug effects ; Biofilms/*drug effects ; Cross Infection/drug therapy ; Disease Models, Animal ; Gram-Positive Bacteria/drug effects/*physiology ; Gram-Positive Bacterial Infections/*drug therapy ; Lepidoptera/*microbiology ; Microbial Sensitivity Tests ; Molecular Structure ; Oleanolic Acid/chemistry/pharmacology ; Pentacyclic Triterpenes/*chemical synthesis/chemistry/pharmacology ; Triterpenes/chemistry/pharmacology ; }, abstract = {Oleanolic acid (OA) and maslinic acid (MA) are pentacyclic triterpenic compounds that abound in industrial olive oil waste. These compounds have renowned antimicrobial properties and lack cytotoxicity in eukaryotic cells as well as resistance mechanisms in bacteria. Despite these advantages, their antimicrobial activity has only been tested in vitro, and derivatives improving this activity have not been reported. In this work, a set of 14 OA and MA C-28 amide derivatives have been synthesized. Two of these derivatives, MA-HDA and OA-HDA, increase the in vitro antimicrobial activity of the parent compounds while reducing their toxicity in most of the Gram-positive bacteria tested, including a methicillin-resistant Staphylococcus aureus-MRSA. MA-HDA also shows an enhanced in vivo efficacy in a Galleria mellonella invertebrate animal model of infection. A preliminary attempt to elucidate their mechanism of action revealed that these compounds are able to penetrate and damage the bacterial cell membrane. More significantly, their capacity to reduce antibiofilm formation in catheters has also been demonstrated in two sets of conditions: a static and a more challenged continuous-flow S. aureus biofilm.}, } @article {pmid31268665, year = {2019}, author = {Banerjee, P and Chanchal, and Jain, D}, title = {Sensor I Regulated ATPase Activity of FleQ Is Essential for Motility to Biofilm Transition in Pseudomonas aeruginosa.}, journal = {ACS chemical biology}, volume = {14}, number = {7}, pages = {1515-1527}, doi = {10.1021/acschembio.9b00255}, pmid = {31268665}, issn = {1554-8937}, mesh = {Adenosine Triphosphatases/chemistry/genetics/*metabolism ; Adenosine Triphosphate/*metabolism ; Amino Acid Sequence ; Bacterial Proteins/chemistry/genetics/*metabolism ; *Biofilms/growth & development ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Point Mutation ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/chemistry/genetics/*physiology ; Trans-Activators/chemistry/genetics/*metabolism ; }, abstract = {Members of the AAA+ (ATPase associated with various cellular activities) family of ATPases couple chemical energy derived from ATP hydrolysis for generation of mechanical force, resulting in conformational changes. The hydrolysis is brought about by highly conserved domains and motifs. The sensor I motif is critical for sensing and hydrolysis of the nucleotide. Pseudomonas aeruginosa FleQ is an ATPase that is a positive regulator of flagellar gene expression. We have determined the crystal structures of the ATPase domain of wild-type FleQ and sensor I mutants H287N and H287A in complex with ATPγS and Mg[2+] to 2.4, 1.95, and 2.25 Å resolution, respectively. The structural data highlight the role of sensor I in regulating the ATPase activity. The in vitro and in vivo data demonstrate that the moderate ATPase activity of FleQ due to the presence of histidine in sensor I is essential for maintaining the monotrichous phenotype and for the rapid motility to biofilm transition.}, } @article {pmid31262835, year = {2019}, author = {Vogeleer, P and Vincent, AT and Chekabab, SM and Charette, SJ and Novikov, A and Caroff, M and Beaudry, F and Jacques, M and Harel, J}, title = {Regulation of waaH by PhoB during Pi Starvation Promotes Biofilm Formation by Escherichia coli O157:H7.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31262835}, issn = {1098-5530}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Escherichia coli O157 ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/drug effects/physiology ; Hexosyltransferases/genetics/*metabolism ; Mutation ; Phosphates/*pharmacology ; Transcription Factors/genetics/*metabolism ; Up-Regulation ; }, abstract = {In open environments such as water, enterohemorrhagic Escherichia coli O157:H7 responds to inorganic phosphate (Pi) starvation by inducing the Pho regulon controlled by PhoB. This activates the phosphate-specific transport (Pst) system that contains a high-affinity Pi transporter. In the Δpst mutant, PhoB is constitutively activated and regulates the expression of genes in the Pho regulon. Here, we show that Pi starvation and deletion of the pst system enhance E. coli O157:H7 biofilm formation. Among differentially expressed genes of EDL933 grown under Pi starvation conditions and in the Δpst mutant, we have found that a member of the PhoB regulon, waaH, predicted to encode a glycosyltransferase, was highly expressed. Interestingly, WaaH contributed to biofilm formation of E. coli O157:H7 during both Pi starvation and in the Δpst mutant. In the Δpst mutant, the presence of waaH was associated with lipopolysaccharide (LPS) R3 core type modifications, whereas in E. coli O157:H7, waaH overexpression had no effect on LPS structure during Pi starvation. Therefore, waaH participates in E. coli O157:H7 biofilm formation during Pi starvation, but its biochemical role remains to be clarified. This study highlights the importance of the Pi starvation stress response to biofilm formation, which may contribute to the persistence of E. coli O157:H7 in the environment.IMPORTANCE Enterohemorrhagic Escherichia coli O157:H7 is a human pathogen that causes bloody diarrhea that can result in renal failure. Outside of mammalian hosts, E. coli O157:H7 survives for extended periods of time in nutrient-poor environments, likely as part of biofilms. In E. coli K-12, the levels of free extracellular Pi affect biofilm formation; however, it was unknown whether Pi influences biofilm formation by E. coli O157:H7. Our results show that upon Pi starvation, PhoB activates waaH expression, which favors biofilm formation by E. coli O157:H7. These findings suggest that WaaH is a target for controlling biofilm formation. Altogether, our work demonstrates how adaptation to Pi starvation allows E. coli O157:H7 to occupy different ecological niches.}, } @article {pmid31261752, year = {2019}, author = {Riau, AK and Aung, TT and Setiawan, M and Yang, L and Yam, GHF and Beuerman, RW and Venkatraman, SS and Mehta, JS}, title = {Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {3}, pages = {}, pmid = {31261752}, issn = {2076-0817}, support = {KPFA/2018/0028//Duke-NUS Khoo Postdoctoral Fellowship Award grant/ ; (SHF/FG661P/2017)//SingHealth Foundation grant/ ; }, abstract = {: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag[+]) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates-high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag[+] release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag[+] released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.}, } @article {pmid31261727, year = {2019}, author = {Chew, SY and Ho, KL and Cheah, YK and Sandai, D and Brown, AJP and Than, LTL}, title = {Physiologically Relevant Alternative Carbon Sources Modulate Biofilm Formation, Cell Wall Architecture, and the Stress and Antifungal Resistance of Candida glabrata.}, journal = {International journal of molecular sciences}, volume = {20}, number = {13}, pages = {}, pmid = {31261727}, issn = {1422-0067}, support = {/WT_/Wellcome Trust/United Kingdom ; MR/M026663/1/MRC_/Medical Research Council/United Kingdom ; MR/N006364/1/MRC_/Medical Research Council/United Kingdom ; 01-01-14-1456FR//Ministry of Education, Malaysia/ ; }, mesh = {Acetates/metabolism ; *Biofilms ; Candida glabrata/drug effects/*metabolism/physiology ; *Carbohydrate Metabolism ; Cell Wall/*metabolism/ultrastructure ; *Drug Resistance, Fungal ; Ethanol/metabolism ; Lactic Acid/metabolism ; Oleic Acids/metabolism ; *Oxidative Stress ; }, abstract = {Flexibility in carbon metabolism is pivotal for the survival and propagation of many human fungal pathogens within host niches. Indeed, flexible carbon assimilation enhances pathogenicity and affects the immunogenicity of Candida albicans. Over the last decade, Candida glabrata has emerged as one of the most common and problematic causes of invasive candidiasis. Despite this, the links between carbon metabolism, fitness, and pathogenicity in C. glabrata are largely unexplored. Therefore, this study has investigated the impact of alternative carbon metabolism on the fitness and pathogenic attributes of C. glabrata. We confirm our previous observation that growth on carbon sources other than glucose, namely acetate, lactate, ethanol, or oleate, attenuates both the planktonic and biofilm growth of C. glabrata, but that biofilms are not significantly affected by growth on glycerol. We extend this by showing that C. glabrata cells grown on these alternative carbon sources undergo cell wall remodeling, which reduces the thickness of their β-glucan and chitin inner layer while increasing their outer mannan layer. Furthermore, alternative carbon sources modulated the oxidative stress resistance of C. glabrata as well as the resistance of C. glabrata to an antifungal drug. In short, key fitness and pathogenic attributes of C. glabrata are shown to be dependent on carbon source. This reaffirms the perspective that the nature of the carbon sources available within specific host niches is crucial for C. glabrata pathogenicity during infection.}, } @article {pmid31260476, year = {2019}, author = {Marini, E and Di Giulio, M and Ginestra, G and Magi, G and Di Lodovico, S and Marino, A and Facinelli, B and Cellini, L and Nostro, A}, title = {Efficacy of carvacrol against resistant rapidly growing mycobacteria in the planktonic and biofilm growth mode.}, journal = {PloS one}, volume = {14}, number = {7}, pages = {e0219038}, pmid = {31260476}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Cymenes/*pharmacology ; Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Mycobacterium Infections, Nontuberculous/drug therapy/microbiology ; Mycobacterium abscessus/drug effects/growth & development/physiology ; Nontuberculous Mycobacteria/*drug effects/growth & development/physiology ; Plankton/drug effects/growth & development/physiology ; Species Specificity ; Time Factors ; }, abstract = {Rapidly growing mycobacteria (RGM) are environmental bacteria found worldwide with a propensity to produce skin and soft-tissue infections. Among them, the most clinically relevant species is Mycobacterium abscessus. Multiple resistance to antibiotics and the ability to form biofilm contributes considerably to the treatment failure. The search of novel anti-mycobacterial agents for the control of biofilm growth mode is crucial. The aim of the present study was to evaluate the activity of carvacrol (CAR) against planktonic and biofilm cells of resistant RGM strains. The susceptibility of RGM strains (n = 11) to antibiotics and CAR was assessed by MIC/MBC evaluation. The CAR activity was estimated by also vapour contact assay. The effect on biofilm formation and preformed biofilm was measured by evaluation of bacterial growth, biofilm biomass and biofilm metabolic activity. MIC values were equal to 64 μg/mL for most of RGM isolates (32-512 μg/mL), MBCs were 2-4 times higher than MICs, and MICs of vapours were lower (16 μg/mL for most RGM isolates) than MICs in liquid phase. Regarding the biofilm, CAR at concentrations of 1/2 × MIC and 1/4 × MIC showed a strong inhibition of biofilm formation (61-77%) and at concentration above the MIC (2-8 × MIC) produced significant inhibition of 4- and 8-day preformed biofilms. In conclusion, CAR could have a potential use, also in vapour phase, for the control of RGM.}, } @article {pmid31260250, year = {2019}, author = {Simcox, LJ and Pereira, RPA and Wellington, EMH and Macpherson, JV}, title = {Boron Doped Diamond as a Low Biofouling Material in Aquatic Environments: Assessment of Pseudomonas aeruginosa Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {28}, pages = {25024-25033}, doi = {10.1021/acsami.9b07245}, pmid = {31260250}, issn = {1944-8252}, mesh = {*Biofilms/drug effects/growth & development ; Biofouling/*prevention & control ; *Boron/chemistry/pharmacology ; *Diamond/chemistry/pharmacology ; Pseudomonas aeruginosa/*physiology ; Surface Properties ; }, abstract = {Boron doped diamond (BDD), given the robustness of the material, is becoming an electrode of choice for applications which require long-term electrochemical monitoring of analytes in aqueous environments. However, despite the extensive work in this area, there are no studies which directly assess the biofilm formation (biofouling) capabilities of the material, which is an essential consideration because biofouling often causes deterioration in the sensor performance. Pseudomonas aeruginosa is one of the most prevalent bacterial pathogens linked to water-related diseases, with a strong capacity for forming biofilms on surfaces that are exposed to aquatic environments. In this study, we comparatively evaluate the biofouling capabilities of oxygen-terminated (O-)BDD against materials commonly employed as either the packaging or sensing element in water quality sensors, with an aim to identify factors which control biofilm formation on BDD. We assess the monospecies biofilm formation of P. aeruginosa in two different growth media, Luria-Bertani, a high nutrient source and drinking water, a low nutrient source, at two different temperatures (20 and 37 °C). Multispecies biofilm formation is also investigated. The performance of O-BDD, when tested against all other materials, promotes the lowest extent of P. aeruginosa monospecies biofilm formation, even with corrections made for total surface area (roughness). Importantly, O-BDD shows the lowest water contact angle of all materials tested, that is, greatest hydrophilicity, strongly suggesting that for these bacterial species, the factors controlling the hydrophilicity of the surface are important in reducing bacterial adhesion. This was further proven by keeping the surface topography fixed and changing surface termination to hydrogen (H-), to produce a strongly hydrophobic surface. A noticeable increase in biofilm formation was found. Doping with boron also results in changes in hydrophobicity/hydrophilicity compared to the undoped counterpart, which in turn affects the bacterial growth. For practical electrochemical sensing applications in aquatic environments, this study highlights the extremely beneficial effects of employing smooth, O-terminated (hydrophilic) BDD electrodes.}, } @article {pmid31259174, year = {2019}, author = {Santos, T and Viala, D and Chambon, C and Esbelin, J and Hébraud, M}, title = {Listeria monocytogenes Biofilm Adaptation to Different Temperatures Seen Through Shotgun Proteomics.}, journal = {Frontiers in nutrition}, volume = {6}, number = {}, pages = {89}, pmid = {31259174}, issn = {2296-861X}, abstract = {Listeria monocytogenes is a foodborne pathogen that can cause invasive severe human illness (listeriosis) in susceptible patients. Most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods. Although initial contamination levels in foods are usually low, the ability of these bacteria to survive and multiply at low temperatures allows it to reach levels high enough to cause disease. This study explores the set of proteins that might have an association with L. monocytogenes adaptation to different temperatures. Cultures were grown in biofilm, the most widespread mode of growth in natural and industrial realms. Protein extractions were performed from three different growth temperatures (10, 25, and 37°C) and two growth phases (early stage and mature biofilm). L. monocytogenes subproteomes were targeted using three extraction methods: trypsin-enzymatic shaving, biotin-labeling and cell fractionation. The different subproteomes obtained were separated and analyzed by shotgun proteomics using high-performance liquid chromatography combined with tandem mass spectrometry (LC-OrbiTrap LTQVelos, ThermoFisher Scientific). A total of 141 (biotinylation), 98 (shaving) and 910 (fractionation) proteins were identified. Throughout the 920 unique proteins identified, many are connected to basic cell functions, but some are linked with thermoregulation. We observed some noteworthy protein abundance shifts associated with the major adaptation to cold mechanisms present in L. monocytogenes, namely: the role of ribosomes and the stressosome with a higher abundance of the general stress protein Ctc (Rl25) and the general stress transcription factor sigma B (σ[B]), changes in cell fluidity and motility seen by higher levels of foldase protein PrsA2 and flagellin (FlaA), the uptake of osmolytes with a higher abundance of glycine betaine (GbuB) and carnitine transporters (OpucA), and the relevance of the overexpression of chaperone proteins such as cold shock proteins (CspLA and Dps). As for 37°C, we observed a significantly higher percentage of proteins associated with transcriptional or translational activity present in higher abundance upon comparison with the colder settings. These contrasts of protein expression throughout several conditions will enrich databases and help to model the regulatory circuitry that drives adaptation of L. monocytogenes to environments.}, } @article {pmid31254829, year = {2019}, author = {Barreiro, P and González, P and Pozo-Antonio, JS}, title = {IR irradiation to remove a sub-aerial biofilm from granitic stones using two different laser systems: An Nd: YAG (1064 nm) and an Er:YAG (2940 nm).}, journal = {The Science of the total environment}, volume = {688}, number = {}, pages = {632-641}, doi = {10.1016/j.scitotenv.2019.06.306}, pmid = {31254829}, issn = {1879-1026}, mesh = {*Biofilms ; *Infrared Rays ; Lasers ; Silicon Dioxide ; }, abstract = {A sub-aerial biofilm (SAB) developed on a granite commonly found in the built cultural heritage of the NW Iberian Peninsula was extracted with 2 different IR irradiations using an Nd:YAG laser at 1064 nm and an Er:YAG laser at 2940 nm. The methodology was based on the application of only one scan in order to evaluate the effect of the laser cleaning operated by applying different consecutive laser scanning and the suitability of these lasers as quick tools. The aim of this comparative study was twofold. The first goal was to find the most satisfactory level of extraction by comparing the results obtained by the different laser sources (IR wavelengths). The other aim was to investigate the by-effects induced by both lasers on each granite-forming mineral. Evaluations were made using stereomicroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results were interpreted in terms of SAB extraction and damage induced on the granite. The results showed that the Nd:YAG laser achieved the most successful level of cleaning, because it extracted the most SAB, while causing the least amount of damage to the surfaces. Regardless of the fluence applied, the Er:YAG laser did not completely extract the SAB in only one scan; in addition, a more intense melting of biotite grains was found, producing amorphous fusion crusts and losing the distinction of the cleavage planes.}, } @article {pmid31254346, year = {2020}, author = {Gonçalves, B and Azevedo, NM and Henriques, M and Silva, S}, title = {Hormones modulate Candida vaginal isolates biofilm formation and decrease their susceptibility to azoles and hydrogen peroxide.}, journal = {Medical mycology}, volume = {58}, number = {3}, pages = {341-350}, doi = {10.1093/mmy/myz070}, pmid = {31254346}, issn = {1460-2709}, mesh = {Antifungal Agents/pharmacology ; Azoles/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Candida glabrata/*drug effects/physiology ; Candidiasis, Vulvovaginal/microbiology ; Estradiol/pharmacology ; Female ; Humans ; Hydrogen Peroxide/*pharmacology ; Hydrogen-Ion Concentration ; Progesterone/*pharmacology ; Vagina/microbiology ; }, abstract = {Vulvovaginal candidiasis (VVC) is an infection usually caused by Candida albicans and increasingly by Candida glabrata, which has an intrinsically high resistance to commonly used antifungals. Candida species possess virulence factors that contribute to VVC development, as the ability to form biofilms in vaginal walls and intrauterine devices. It is known that VVC is promoted by conditions that increase the hormones levels, during pregnancy, however, the effects of hormones on Candida cells are poorly studied, especially in C. glabrata. Thus, the influence of progesterone and β-estradiol, at normal cycle and pregnancy concentrations, on biofilm formation and resistance of C. albicans and C. glabrata vaginal isolates, was analyzed using acidic conditions (pH 4). Biofilms of C. albicans developed in the presence of hormones presented reduced biomass (up to 65%) and impaired cells ability to produce filamentous forms. On the other hand, C. glabrata presented high adaptation to the presence of hormones, which did not affect its biofilm formation. Additionally, hormones impaired the susceptibility of C. albicans and C. glabrata cells to azoles, with potential clinical significance in the presence of pregnancy hormone levels. A similar result was obtained for the susceptibility to hydrogen peroxide, a biological vaginal barrier against Candida growth. Overall, the results of this study suggest that hormones may act as environmental cues promoting Candida protection from vaginal defenses and harmful conditions, what may have implications in Candida vaginal pathogenicity and treatment of VVC, especially in C. glabrata infections due to its high adaptability to vaginal conditions.}, } @article {pmid31253082, year = {2019}, author = {Suryaletha, K and Narendrakumar, L and John, J and Radhakrishnan, MP and George, S and Thomas, S}, title = {Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {146}, pmid = {31253082}, issn = {1471-2180}, mesh = {Amino Acids/metabolism/physiology ; Arginine/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Carbohydrate Metabolism/genetics/physiology ; Enterococcus faecalis/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Humans ; Membrane Proteins ; Metabolic Networks and Pathways/genetics/physiology ; Protein Folding ; *Proteomics ; Quorum Sensing/genetics/physiology ; Rhamnose/biosynthesis ; }, abstract = {BACKGROUND: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation.

RESULTS: The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community.

CONCLUSIONS: The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections.}, } @article {pmid31252357, year = {2019}, author = {Shi, LD and Wang, M and Li, ZY and Lai, CY and Zhao, HP}, title = {Dissolved oxygen has no inhibition on methane oxidation coupled to selenate reduction in a membrane biofilm reactor.}, journal = {Chemosphere}, volume = {234}, number = {}, pages = {855-863}, doi = {10.1016/j.chemosphere.2019.06.138}, pmid = {31252357}, issn = {1879-1298}, mesh = {Bacteria/enzymology/isolation & purification ; Biofilms ; Bioreactors/microbiology ; Membranes, Artificial ; Methane/*chemistry ; Nitrates/metabolism ; Nitrites/metabolism ; Oxidation-Reduction ; Oxygen/*pharmacology ; Selenic Acid/*chemistry/isolation & purification ; }, abstract = {Methane oxidation coupled to selenate reduction has been suggested as a promising technology to bio-remediate selenium contaminated environments. However, the effect of dissolved oxygen (DO) on this process remained unclear. Here, we investigate the feasibility of selenate removal at two distinct DO concentrations. A membrane biofilm reactor (MBfR) was initially fed with ∼5 mg Se/L and then lowered to ∼1 mg Se/L of selenate, under anoxic condition containing ∼0.2 mg/L of influent DO. Selenate removal reached approximately 90% without selenite accumulation after one-month operation. Then 6-7 mg/L of DO was introduced and showed no apparent effect on selenate reduction in the subsequent operation. Electron microscopy suggested elevated oxygen exposure did not affect microbial shapes. 16S rDNA sequencing showed the aerobic methanotroph Methylocystis increased, while possible selenate reducers, Ignavibacterium and Bradyrhizobium, maintained stable after oxygen boost. Gene analysis indicated that nitrate/nitrite reductases positively correlated with selenate removal flux and were not remarkably affected by oxygen addition. Reversely, enzymes related with aerobic methane oxidation were obviously improved. This study provides a potential technology for selenate removal from oxygenated environments in a methane-based MBfR.}, } @article {pmid31251598, year = {2019}, author = {Jack, AA and Nordli, HR and Powell, LC and Farnell, DJJ and Pukstad, B and Rye, PD and Thomas, DW and Chinga-Carrasco, G and Hill, KE}, title = {Cellulose Nanofibril Formulations Incorporating a Low-Molecular-Weight Alginate Oligosaccharide Modify Bacterial Biofilm Development.}, journal = {Biomacromolecules}, volume = {20}, number = {8}, pages = {2953-2961}, doi = {10.1021/acs.biomac.9b00522}, pmid = {31251598}, issn = {1526-4602}, mesh = {Alginates/*chemistry ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects/*growth & development ; Cellulose/*chemistry ; Drug Compounding ; Humans ; Microbial Sensitivity Tests ; Molecular Weight ; Nanofibers/*chemistry ; Oligosaccharides/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Skin/drug effects ; Staphylococcus aureus/drug effects ; Wound Healing/*drug effects ; }, abstract = {Cellulose nanofibrils (CNFs) from wood pulp are a renewable material possessing advantages for biomedical applications because of their customizable porosity, mechanical strength, translucency, and environmental biodegradability. Here, we investigated the growth of multispecies wound biofilms on CNF formulated as aerogels and films incorporating the low-molecular-weight alginate oligosaccharide OligoG CF-5/20 to evaluate their structural and antimicrobial properties. Overnight microbial cultures were adjusted to 2.8 × 10[9] colony-forming units (cfu) mL[-1] in Mueller Hinton broth and growth rates of Pseudomonas aeruginosa PAO1 and Staphylococcus aureus 1061A monitored for 24 h in CNF dispersions sterilized by γ-irradiation. Two CNF formulations were prepared (20 g m[-2]) with CNF as air-dried films or freeze-dried aerogels, with or without incorporation of an antimicrobial alginate oligosaccharide (OligoG CF-5/20) as a surface coating or bionanocomposite, respectively. The materials were structurally characterized by scanning electron microscopy (SEM) and laser profilometry (LP). The antimicrobial properties of the formulations were assessed using single- and mixed-species biofilms grown on the materials and analyzed using LIVE/DEAD staining with confocal laser scanning microscopy (CLSM) and COMSTAT software. OligoG-CNF suspensions significantly decreased the growth of both bacterial strains at OligoG concentrations >2.58% (P < 0.05). SEM showed that aerogel-OligoG bionanocomposite formulations had a more open three-dimensional structure, whereas LP showed that film formulations coated with OligoG were significantly smoother than untreated films or films incorporating PEG400 as a plasticizer (P < 0.05). CLSM of biofilms grown on films incorporating OligoG demonstrated altered biofilm architecture, with reduced biomass and decreased cell viability. The OligoG-CNF formulations as aerogels or films both inhibited pyocyanin production (P < 0.05). These novel CNF formulations or bionanocomposites were able to modify bacterial growth, biofilm development, and virulence factor production in vitro. These data support the potential of OligoG and CNF bionanocomposites for use in biomedical applications where prevention of infection or biofilm growth is required.}, } @article {pmid31251015, year = {2019}, author = {Ng, CK and Karahan, HE and Loo, SCJ and Chen, Y and Cao, B}, title = {Biofilm-Templated Heteroatom-Doped Carbon-Palladium Nanocomposite Catalyst for Hexavalent Chromium Reduction.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {27}, pages = {24018-24026}, doi = {10.1021/acsami.9b04095}, pmid = {31251015}, issn = {1944-8252}, abstract = {In this study, we report an interdisciplinary and novel strategy toward biofilm engineering for the development of a biofilm-templated heteroatom-doped catalytic system through bioreduction and biofilm matrix-facilitated immobilization of the in situ-formed catalytic nanoparticles followed by controlled pyrolysis. We showed that (i) even under room temperature and bulk aerobic conditions, Shewanella oneidensis MR-1 biofilms reduced Pd(II) to form Pd(0) nanocrystals (∼10 to 20 nm) that were immobilized in the biofilm matrix and in cellular membranes, (ii) the MR-1 biofilms with the immobilized Pd(0) nanocrystals exhibited nanocatalytic activity, (iii) exposure to Pd(II) greatly increased the rate of cell detachment from the biofilm and posed a risk of biofilm dispersal, (iv) controlled pyrolysis (carbonization) of the biofilm led to the formation of a stable heteroatom-doped carbon-palladium (C-Pd) nanocomposite catalyst, and (v) the biofilm-templated C-Pd nanocomposite catalyst exhibited a high Cr(VI) reduction activity and maintained a high reduction rate over multiple catalytic cycles. Considering that bacteria are capable of synthesizing a wide range of metal and metalloid nanoparticles, the biofilm-templated approach for the fabrication of the catalytic C-Pd nanocomposite we have demonstrated here should prove to be widely applicable for the production of different nanocomposites that are of importance to various environmental applications.}, } @article {pmid31250405, year = {2019}, author = {Pham, DTN and Khan, F and Phan, TTV and Park, SK and Manivasagan, P and Oh, J and Kim, YM}, title = {Biofilm inhibition, modulation of virulence and motility properties by FeOOH nanoparticle in Pseudomonas aeruginosa.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {50}, number = {3}, pages = {791-805}, pmid = {31250405}, issn = {1678-4405}, support = {20150220//Ministry of Education/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects ; Iron/chemistry/*pharmacology ; Nanoparticles/chemistry ; Pseudomonas aeruginosa/*drug effects/physiology ; Virulence Factors/genetics/*metabolism ; }, abstract = {Biofilm formation is one of the resistance mechanisms of Pseudomonas aeruginosa against antimicrobial compounds. Biofilm formation also characterizes for the infection and pathogenesis of P. aeruginosa, along with production of various virulence factors. With recent development of nanotechnology, the present study aims to employ the synthetic iron nanoparticle (FeOOH-NP) as an active agent to inhibit the formation of P. aeruginosa biofilm. The FeOOH-NP was synthesized and characterized with rod shape and average size of 40 nm. Inhibition of biofilm formation by the FeOOH-NP is in a concentration-dependent manner, with inhibition of biofilm formation increased as the FeOOH-NP concentration increased. Microscopic observations also confirmed the disruption of the biofilm architecture in the presence of the FeOOH-NP. In addition, the presence of the FeOOH-NP was also found to modulate bacterial motility as well as some other important virulence factors produced simultaneously with biofilm formation. These findings provide insights to anti-biofilm effect of a new iron NP, contributing to the search for an effective agent to combat P. aeruginosa infections resulted from biofilm formation.}, } @article {pmid31250387, year = {2019}, author = {Fallatah, H and Elhaneid, M and Ali-Boucetta, H and Overton, TW and El Kadri, H and Gkatzionis, K}, title = {Antibacterial effect of graphene oxide (GO) nano-particles against Pseudomonas putida biofilm of variable age.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {24}, pages = {25057-25070}, pmid = {31250387}, issn = {1614-7499}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Graphite/chemistry/*pharmacology ; Oxides/*chemistry ; Pseudomonas putida/*chemistry/physiology ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Graphene oxide (GO) has been reported to possess antibacterial activity; therefore, its accumulation in the environment could affect microbial communities such as biofilms. The susceptibility of biofilms to antimicrobials is known to depend on the stage of biofilm maturity. The aim of this study was to investigate the effect of GO nano-particles on Pseudomonas putida KT2440 biofilm of variable age. FT-IR, UV-vis, and Raman spectroscopy confirmed the oxidation of graphene while XPS confirmed the high purity of the synthesised GO over 6 months. Biofilms varying in maturity (24, 48, and 72 h) were formed using a CDC reactor and were treated with GO (85 μg/mL or 8.5 μg/mL). The viability of P. putida was monitored by culture on media and the bacterial membrane integrity was assessed using flow cytometry. P. putida cells were observed using confocal microscopy and SEM. The results showed that GO significantly reduced the viability of 48-h biofilm and detached biofilm cells associated with membrane damage while the viability was not affected in 24- and 72-h biofilms and detached biofilm cells. The results showed that susceptibility of P. putida biofilm to GO varied according to age which may be due to changes in the physiological state of cells during maturation. Graphical abstract.}, } @article {pmid31250076, year = {2020}, author = {Jeong, SY and Lee, CH and Yi, T and Kim, TG}, title = {Effects of Quorum Quenching on Biofilm Metacommunity in a Membrane Bioreactor.}, journal = {Microbial ecology}, volume = {79}, number = {1}, pages = {84-97}, pmid = {31250076}, issn = {1432-184X}, support = {2018R1D1A1B07048872//Ministry of Education/ ; }, mesh = {Bacteria/classification/genetics/growth & development ; Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/*microbiology ; Fungi/classification/genetics/growth & development/*physiology ; Membranes, Artificial ; *Quorum Sensing ; }, abstract = {Quorum quenching (QQ) has received attention for the control of biofilms, e.g., biofilms that cause biofouling in membrane bioreactors (MBRs). Despite the efficacy of QQ on biofouling, it is elusive how QQ influences biofilm formation on membranes. A pilot-scale QQ-MBR and non-QQ-MBR were identically operated for 4 days and 8 days to destructively sample the membranes. QQ prolonged the membrane filterability by 43% with no harmful influence on MBR performance. qPCR showed no effect of QQ on microbial density during either of these time periods. Community comparisons revealed that QQ influenced the bacterial and fungal community structures, and the fungal structure corresponded with the bacterial structure. Metacommunity and spatial analyses showed that QQ induced structural variation rather than compositional variation of bacteria and fungi. Moreover, QQ considerably enhanced the bacterial dispersal across membrane during the early development. As the dispersal enhancement by QQ counteracted the ecological drift, it eliminated the distance-decay relationship, reflecting a neutral theory archetype of metacommunity. Network analyses showed that QQ substantially reduced the amount and magnitude of interactions, e.g., competition and cooperation, for bacteria and fungi, and weakened their network structures, irrespective of time. Additionally, QQ suppressed the growth of specific microbial species (e.g., Acinetobacter), abundant and widespread at the early stage. These findings suggest that QQ influenced the community dynamics at the regional and local levels, correspondingly the ecological selection and dispersal processes, during the biofilm development.}, } @article {pmid31246756, year = {2019}, author = {Jewell, ML and Fickas, B and Jewell, H and Jewell, ML}, title = {Implant Surface Options and Biofilm Mitigation Strategies.}, journal = {Plastic and reconstructive surgery}, volume = {144}, number = {1S Utilizing a Spectrum of Cohesive Implants in Aesthetic and Reconstructive Breast Surgery}, pages = {13S-20S}, doi = {10.1097/PRS.0000000000005946}, pmid = {31246756}, issn = {1529-4242}, mesh = {Anti-Infective Agents, Local/*administration & dosage ; Biofilms/*drug effects ; Breast Implantation/*adverse effects/instrumentation/methods ; Breast Implants/*microbiology ; Female ; Gram-Negative Bacteria/pathogenicity/physiology ; Gram-Positive Bacteria/pathogenicity/physiology ; Humans ; Povidone-Iodine/administration & dosage ; Prosthesis-Related Infections/etiology/*prevention & control ; Surface Properties ; Therapeutic Irrigation ; }, abstract = {Two important topics in breast augmentation and reconstruction relate to device surface texture and practices to mitigate biofilm contamination of implants. Breast augmentation can be considered a manufacturing process where planning concepts of process engineering and quality can be used to produce great outcomes. This article reviews the options available for surgeons with regards to device surface texture selection and practices to mitigate biofilm contamination of implants at the time of surgery.}, } @article {pmid31246167, year = {2019}, author = {Pal, S and Verma, J and Mallick, S and Rastogi, SK and Kumar, A and Ghosh, AS}, title = {Absence of the glycosyltransferase WcaJ in Klebsiella pneumoniae ATCC13883 affects biofilm formation, increases polymyxin resistance and reduces murine macrophage activation.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {8}, pages = {891-904}, doi = {10.1099/mic.0.000827}, pmid = {31246167}, issn = {1465-2080}, mesh = {Animals ; Bacterial Capsules/immunology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Drug Resistance, Bacterial/genetics ; Gene Expression Regulation, Bacterial ; Glycosyltransferases/*genetics/metabolism ; Klebsiella pneumoniae/drug effects/*genetics/growth & development/immunology ; Macrophage Activation/*immunology ; Mice ; Polymyxins/pharmacology ; Polysaccharides/*immunology/metabolism ; Quinolones/pharmacology ; Virulence ; }, abstract = {Multidrug-resistant Klebsiella pneumoniae has emerged as one of the deadliest opportunistic nosocomial pathogens that forms biofilm for the establishment of chronic K. pneumoniae infections. Herein, we made an attempt to identify the genes involved in biofilm formation in the strain K. pneumoniae ATCC13883. To achieve this, we constructed mini-Tn5 transposon insertion mutants and screened them for biofilm production. We observed that the biofilm formation was enhanced in the mutant where the wcaJ gene was disrupted. WcaJ is the initiating enzyme of colanic acid synthesis and loads the first sugar (glucose-1-P) on the lipid carrier undecaprenyl phosphate. The absence of this glycosyltransferase results in the absence of colanic acid, which renders a non-mucoid phenotype to the mutant. Further, to determine the effect of mucoidy on antibiotic susceptibility, we tested the sensitivity of the strains towards different groups of antibiotics. Unlike the mucoid strains, the resistance of the non-mucoid cells was greater for polymyxins, but less for quinolones. Capsular polysaccharides are known to have a protective effect against phagocytosis, therefore we assessed the role of colanic acid in virulence by conducting infection studies on murine macrophages. Surprisingly, the ΔwcaJ strain was less efficient in macrophage activation and was not readily phagocytosed. Thus, the presence of colanic acid appeared to increase the immunogenicity of K. pneumoniae. Overall, the results indicate that the presence of colanic acid increases the vulnerability of K. pneumoniae towards both polymyxins and macrophages, implying that the mucoid strains are less threatening as compared to their high biofilm forming non-mucoid counterparts.}, } @article {pmid31244785, year = {2019}, author = {Zeng, S and Constant, P and Yang, D and Baulard, A and Lefèvre, P and Daffé, M and Wattiez, R and Fontaine, V}, title = {Cpn60.1 (GroEL1) Contributes to Mycobacterial Crabtree Effect: Implications for Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1149}, pmid = {31244785}, issn = {1664-302X}, abstract = {Biofilm formation is a survival strategy for microorganisms facing a hostile environment. Under biofilm, bacteria are better protected against antibacterial drugs and the immune response, increasing treatment difficulty, as persistent populations recalcitrant to chemotherapy are promoted. Deciphering mechanisms leading to biofilms could, thus, be beneficial to obtain new antibacterial drug candidates. Here, we show that mycobacterial biofilm formation is linked to excess glycerol adaptation and the concomitant establishment of the Crabtree effect. This effect is characterized by respiratory reprogramming, ATP downregulation, and secretion of various metabolites including pyruvate, acetate, succinate, and glutamate. Interestingly, the Crabtree effect was abnormal in a mycobacterial strain deficient for Cpn60.1 (GroEL1). Indeed, this mutant strain had a compromised ability to downregulate ATP and secreted more pyruvate, acetate, succinate, and glutamate in the culture medium. Importantly, the mutant strain had higher intracellular pyruvate and produced more toxic methylglyoxal, suggesting a glycolytic stress leading to growth stasis and consequently biofilm failure. This study demonstrates, for the first time, the link between mycobacterial biofilm formation and the Crabtree effect.}, } @article {pmid31241174, year = {2019}, author = {Tang, Y and Zhang, Z and Rittmann, BE and Lee, HS}, title = {Kinetics of anaerobic methane oxidation coupled to denitrification in the membrane biofilm reactor.}, journal = {Biotechnology and bioengineering}, volume = {116}, number = {10}, pages = {2550-2560}, doi = {10.1002/bit.27098}, pmid = {31241174}, issn = {1097-0290}, mesh = {Anaerobiosis ; Biofilms/*growth & development ; *Bioreactors ; *Denitrification ; Methane/*metabolism ; *Models, Biological ; }, abstract = {Anaerobic oxidation of methane coupled to denitrification (AOM-D) in a membrane biofilm reactor (MBfR), a platform used for efficiently coupling gas delivery and biofilm development, has attracted attention in recent years due to the low cost and high availability of methane. However, experimental studies have shown that the nitrate-removal flux in the CH4 -based MBfR (<1.0 g N/m[2] -day) is about one order of magnitude smaller than that in the H2 -based MBfR (1.1-6.7 g N/m[2] -day). A one-dimensional multispecies biofilm model predicts that the nitrate-removal flux in the CH4 -based MBfR is limited to <1.7 g N/m[2] -day, consistent with the experimental studies reported in the literature. The model also determines the two major limiting factors for the nitrate-removal flux: The methane half-maximum-rate concentration (K2) and the specific maximum methane utilization rate of the AOM-D syntrophic consortium (kmax2), with kmax2 being more important. Model simulations show that increasing kmax2 to >3 g chemical oxygen demand (COD)/g cell-day (from its current 1.8 g COD/g cell-day) and developing a new membrane with doubled methane-delivery capacity (Dm) could bring the nitrate-removal flux to ≥4.0 g N/m[2] -day, which is close to the nitrate-removal flux for the H2 -based MBfR. Further increase of the maximum nitrate-removal flux can be achieved when Dm and kmax2 increase together.}, } @article {pmid31239789, year = {2019}, author = {Nuryastuti, T and Umaroh, N and Asdie, RH and Sari, IP and Musthafa, A}, title = {Pan-drug-resistant and biofilm-producing strain of Burkholderia pseudomallei: first report of melioidosis from a diabetic patient in Yogyakarta, Indonesia [Response to Letter].}, journal = {International medical case reports journal}, volume = {12}, number = {}, pages = {171-172}, pmid = {31239789}, issn = {1179-142X}, } @article {pmid31239382, year = {2019}, author = {Kavanaugh, JS and Flack, CE and Lister, J and Ricker, EB and Ibberson, CB and Jenul, C and Moormeier, DE and Delmain, EA and Bayles, KW and Horswill, AR}, title = {Identification of Extracellular DNA-Binding Proteins in the Biofilm Matrix.}, journal = {mBio}, volume = {10}, number = {3}, pages = {}, pmid = {31239382}, issn = {2150-7511}, support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; R01 AI125589/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Blotting, Southwestern ; DNA, Bacterial/genetics ; DNA-Binding Proteins/genetics/*metabolism ; Extracellular Polymeric Substance Matrix/genetics ; Lipoproteins/genetics/*metabolism ; Mass Spectrometry ; Staphylococcus aureus/*genetics/physiology ; Static Electricity ; }, abstract = {We developed a new approach that couples Southwestern blotting and mass spectrometry to discover proteins that bind extracellular DNA (eDNA) in bacterial biofilms. Using Staphylococcus aureus as a model pathogen, we identified proteins with known DNA-binding activity and uncovered a series of lipoproteins with previously unrecognized DNA-binding activity. We demonstrated that expression of these lipoproteins results in an eDNA-dependent biofilm enhancement. Additionally, we found that while deletion of lipoproteins had a minimal impact on biofilm accumulation, these lipoprotein mutations increased biofilm porosity, suggesting that lipoproteins and their associated interactions contribute to biofilm structure. For one of the lipoproteins, SaeP, we showed that the biofilm phenotype requires the lipoprotein to be anchored to the outside of the cellular membrane, and we further showed that increased SaeP expression correlates with more retention of high-molecular-weight DNA on the bacterial cell surface. SaeP is a known auxiliary protein of the SaeRS system, and we also demonstrated that the levels of SaeP correlate with nuclease production, which can further impact biofilm development. It has been reported that S. aureus biofilms are stabilized by positively charged cytoplasmic proteins that are released into the extracellular environment, where they make favorable electrostatic interactions with the negatively charged cell surface and eDNA. In this work we extend this electrostatic net model to include secreted eDNA-binding proteins and membrane-attached lipoproteins that can function as anchor points between eDNA in the biofilm matrix and the bacterial cell surface.IMPORTANCE Many bacteria are capable of forming biofilms encased in a matrix of self-produced extracellular polymeric substances (EPS) that protects them from chemotherapies and the host defenses. As a result of these inherent resistance mechanisms, bacterial biofilms are extremely difficult to eradicate and are associated with chronic wounds, orthopedic and surgical wound infections, and invasive infections, such as infective endocarditis and osteomyelitis. It is therefore important to understand the nature of the interactions between the bacterial cell surface and EPS that stabilize biofilms. Extracellular DNA (eDNA) has been recognized as an EPS constituent for many bacterial species and has been shown to be important in promoting biofilm formation. Using Staphylococcus aureus biofilms, we show that membrane-attached lipoproteins can interact with the eDNA in the biofilm matrix and promote biofilm formation, which suggests that lipoproteins are potential targets for novel therapies aimed at disrupting bacterial biofilms.}, } @article {pmid31236717, year = {2019}, author = {Cavero-Olguin, VH and Hatti-Kaul, R and Cardenas-Alegria, OV and Gutierrez-Valverde, M and Alfaro-Flores, A and Romero-Calle, DX and Alvarez-Aliaga, MT}, title = {Stress induced biofilm formation in Propionibacterium acidipropionici and use in propionic acid production.}, journal = {World journal of microbiology & biotechnology}, volume = {35}, number = {7}, pages = {101}, pmid = {31236717}, issn = {1573-0972}, support = {2008-00849//VINNOVA/ ; }, mesh = {*Biofilms ; Bioreactors/microbiology ; Cells, Immobilized ; Fermentation ; Gene Expression Regulation ; Genes, Bacterial ; Glycerol/metabolism ; In Situ Hybridization, Fluorescence ; Microscopy, Atomic Force ; Propionates/*metabolism ; Propionibacterium/genetics/*metabolism ; RNA, Ribosomal, 16S/genetics/isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; *Stress, Physiological ; Trehalose/metabolism ; }, abstract = {Propionibacterium acidipropionici produces propionic acid from different sugars and glycerol; the production can be improved by high cell density fermentations using immobilized cells that help to overcome the limitations of the non-productive lag phase and product inhibition. In this study, the use of stress factors to induce P. acidipropionici to form biofilm and its use as an immobilization procedure in fermentations in bioreactors for producing propionic acid was investigated. Citric acid and sodium chloride increased exopolysaccharide production, biofilm forming capacity index and trehalose production. Analysis of the expression of trehalose synthesis-related genes otsA and treY by RT-qPCR showed significantly increased expression of only treY during log phase with citric acid, while FISH analysis showed expression of treY and luxS under the influence of both stress factors. The stress factors were then used for development of microbial biofilms as immobilization procedure on Poraver® and AnoxKaldnes® carriers in recycle batch reactors for propionic acid production from 20 g/L glycerol. Highest productivities of 0.7 and 0.78 g/L/h were obtained in Poraver® reactors, and 0.39 and 0.43 g/L/h in AnoxKaldnes® reactors with citric acid and NaCl, respectively.}, } @article {pmid31235750, year = {2019}, author = {Costa, ACBP and Omran, RP and Correia-Mesquita, TO and Dumeaux, V and Whiteway, M}, title = {Screening of Candida albicans GRACE library revealed a unique pattern of biofilm formation under repression of the essential gene ILS1.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {9187}, pmid = {31235750}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Candida albicans/*physiology ; Fungal Proteins/genetics/*metabolism ; Gene Expression ; Gene Expression Regulation, Fungal ; Isoleucine-tRNA Ligase/genetics/*metabolism ; Mutation ; }, abstract = {Candida albicans biofilm formation is governed by a regulatory circuit comprising nine transcription factors which control a network of target genes. However, there are still unknown genes contributing to biofilm features. Thus, the GRACE library was screened to identify genes involved in mature biofilm development. Twenty-nine conditional mutants were selected for a second screening revealing three groups of genes: twenty- two conditional mutants were defective for normal growth and unable to form biofilms; six strains, conditionally defective in genes ARC40, ARC35, ORF19.2438, SKP1, ERG6, and ADE5,7 that are likely essential or involved in general cell processes, grew normally as free-floating cells but produced less biofilm; finally, the conditional strain for a putative essential isoleucyl- tRNA synthetase gene, ILS1, was unable to grow as yeast-phase cells but was capable of producing a tridimensional biofilm structure in spite of reduced metabolic activity. This unique biofilm still relied on the classical biofilm genes, while it differentially induced groups of genes involved in adhesion, protein synthesis, cell wall organization, and protein folding. Although the conditional mutant repressed genes annotated for morphology and homeostasis processes affecting morphology and metabolism, the dynamic cell growth enabled the formation of a complex biofilm community independent of ILS1.}, } @article {pmid31235348, year = {2019}, author = {Takeuchi, N and Ohkusu, M and Wada, N and Kurosawa, S and Miyabe, A and Yamaguchi, M and Nahm, MH and Ishiwada, N}, title = {Molecular typing, antibiotic susceptibility, and biofilm production in nonencapsulated Streptococcus pneumoniae isolated from children in Japan.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {25}, number = {10}, pages = {750-757}, doi = {10.1016/j.jiac.2019.02.007}, pmid = {31235348}, issn = {1437-7780}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Drug Resistance, Bacterial/genetics ; Humans ; Infant ; Infant, Newborn ; Japan/epidemiology ; Microbial Sensitivity Tests ; Molecular Typing/methods ; Mutation ; Nasal Mucosa/microbiology ; Penicillin-Binding Proteins/genetics ; Pneumococcal Infections/epidemiology/microbiology/*therapy ; Pneumococcal Vaccines/*therapeutic use ; Prevalence ; Serotyping ; Streptococcus pneumoniae/genetics/immunology/*isolation & purification ; Virulence Factors/genetics ; }, abstract = {The prevalence of nonencapsulated Streptococcus pneumoniae (NESp) has increased with the introduction of pneumococcal conjugate vaccines in children; however, the bacteriological characteristics of NESp have not been sufficiently clarified. In this study, NESp strains isolated from the nasopharyngeal carriage of children from four nursery schools in Japan were analyzed for molecular type, antibiotic susceptibility, and biofilm productivity. A total of 152 putative S. pneumoniae strains were identified by optochin-susceptibility analysis, of which 21 were not serotypeable by slide agglutination, quellung reaction, or multiplex PCR. Among these 21 strains, three were lytA-negative and, therefore, not S. pneumoniae. The remaining 18 strains were positive for lytA, ply, pspK, and bile solubility and were confirmed as NESp. Therefore, the isolation rate of NESp in the S. pneumoniae strains in this study was 12.0% (18/149). Molecular-typing analyses classified five strains as two existing sequence types (STs; ST7502 and ST7786), and 13 strains formed four novel STs. Horizontal spread was suspected, because strains with the same ST were often isolated from the same nursery school. The NESp isolates were generally susceptible to most antimicrobials, with the exception of macrolides; however, all isolates possessed more than one abnormal penicillin-binding protein gene. Furthermore, NESp strains were more effective than encapsulated counterparts at forming biofilms, which showed obvious differences in morphology. These data indicated that NESp strains should be continuously monitored as emerging respiratory pathogens.}, } @article {pmid31234908, year = {2019}, author = {Hagos, DG and Mezgebo, TA and Berhane, S and Medhanyie, AA}, title = {Biofilm and hemagglutinin formation: a Hallmark for drug resistant uropathogenic Escherichia coli.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {358}, pmid = {31234908}, issn = {1756-0500}, support = {40//Mekelle University/ ; 000.00 Eth.Birr//Mekelle University/ ; }, mesh = {Adolescent ; Adult ; Biofilms/*growth & development ; *Drug Resistance, Bacterial ; Female ; Hemagglutinins/*metabolism ; Humans ; Logistic Models ; Multivariate Analysis ; Uropathogenic Escherichia coli/*physiology ; Young Adult ; }, abstract = {OBJECTIVE: Urinary tract infection (UTI) is one of the most frequent disease encounters in pregnant mothers, and the most drug resistant, biofilm and hemagglutinin producer Uropathogenic Escherichia coli (UPEC) is the major etiologic agent. Therefore, the aim of this study was to assess the association between the antimicrobial resistance, and biofilm and hemagglutinin production of Uropathogenic Escherichia coli.

RESULTS: UTI among the study participants was 27.3%; and UPEC was found the major etiologic agent followed by coagulase negative staphylococcus. Risk factors, previous history of catheterization and previous history of UTI were found significantly associated with UTI, recurrent UTI, drug resistance and biofilm formation. Of the tested antibiotics, nitrofurantoin was the most effective drug for UPEC. Nearly 100% of the biofilm producers were resistant to norfloxacin, cotrimoxazole, and gentamicin.}, } @article {pmid31234765, year = {2019}, author = {Grishin, AV and Karyagina, AS}, title = {Polysaccharide Galactan Inhibits Pseudomonas aeruginosa Biofilm Formation but Protects Pre-formed Biofilms from Antibiotics.}, journal = {Biochemistry. Biokhimiia}, volume = {84}, number = {5}, pages = {509-519}, doi = {10.1134/S0006297919050055}, pmid = {31234765}, issn = {1608-3040}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Galactans/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; Pseudomonas aeruginosa/growth & development/*physiology ; Solanum tuberosum/metabolism ; }, abstract = {Microorganisms residing within a biofilm become more tolerant to antibiotics and other types of adverse impact, and biofilm formation by pathogenic bacteria is an important problem of current medicine. Polysaccharides that prevent biofilm formation are among the promising candidates to help tackle this problem. Earlier we demonstrated the ability of a potato polysaccharide galactan to inhibit biofilm formation by a Pseudomonas aeruginosa clinical isolate. Here we investigate the effect of potato galactan on P. aeruginosa biofilms in more detail. Microscopic analysis indicated that the galactan did not interfere with the adhesion of bacterial cells to the substrate but prevented the build-up of bacterial biomass. Moreover, the galactan not only inhibited biofilm formation, but partially destroyed pre-formed biofilms. Presumably, this activity of the galactan was due to the excessive aggregation of bacterial cells, which prohibited the formation and maintenance of proper biofilm architecture, or due to some other mechanisms of biofilm structure remodeling. This led to an unexpected effect, i.e., P. aeruginosa biofilms treated with an antibiotic and the galactan retained more viable bacterial cells compared to biofilms treated with the antibiotic alone. Galactan is the first polysaccharide demonstrated to exert such effect on bacterial biofilms.}, } @article {pmid31233774, year = {2019}, author = {Nakamura, H and Shimizu, T and Takatani, A and Suematsu, T and Nakamura, T and Kawakami, A}, title = {Initial human T-cell leukemia virus type 1 infection of the salivary gland epithelial cells requires a biofilm-like structure.}, journal = {Virus research}, volume = {269}, number = {}, pages = {197643}, doi = {10.1016/j.virusres.2019.197643}, pmid = {31233774}, issn = {1872-7492}, mesh = {Aged ; Apoptosis ; *Biofilms ; Biopsy ; Cell Line ; Cells, Cultured ; Coculture Techniques ; Epithelial Cells/ultrastructure/*virology ; Extracellular Matrix Proteins/genetics ; Female ; Fluorescent Antibody Technique ; Human T-lymphotropic virus 1/*physiology ; Humans ; Microscopy, Electron ; Middle Aged ; Salivary Glands/cytology/pathology/*virology ; Sjogren's Syndrome ; }, abstract = {The initial phase of the human T cell leukemia virus-1 (HTLV-1) infection of salivary gland epithelial cells (SGECs) was examined. SGECs of patients with Sjögren's syndrome (SS) and non-SS subjects were co-cultured with the HTLV-1-infected cell line HCT-5 or MOLT-4, then immunofluorescence (IF), scanning and transmission electron microscopy (SEM/TEM) were employed. The extracellular matrix and linker proteins galectin-3, agrin, and tetherin were expressed on the surfaces of both HCT-5 and MOLT-4 cells. HTLV-1 Gag-positive spots were observed on adjacent SGECs after 1 h of co-culture with HCT-5. Both in subjects with and those without SS, agrin and tetherin were co-expressed with HTLV-1 Gag on SGECs after co-culture with HCT-5, although no polarization of HTLV-1 Gag and relevant molecules was observed. SEM showed HTLV-1 virions that were found on HCT-5 were observed in the interfaces between HCT-5 cells and SGECs. TEM imaging showed that HTLV-1 virions were transmitted to SGECs at the interface with thin film-like structure, while HTLV-1 virions were released from the surface of HCT-5 cells. No endogenous retroviruses were observed. These results showed that the initial phase of HTLV-1 infection toward SGECs of SS was mediated not by viral synapses, but by biofilm-like components.}, } @article {pmid31233560, year = {2019}, author = {Mendis, HC and Ozcan, A and Santra, S and De La Fuente, L}, title = {A novel Zn chelate (TSOL) that moves systemically in citrus plants inhibits growth and biofilm formation of bacterial pathogens.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0218900}, pmid = {31233560}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Citrus/*microbiology ; Liberibacter ; Microbial Sensitivity Tests/methods ; Plant Diseases/microbiology ; Plant Leaves/microbiology ; Rhizobiaceae/*drug effects ; Xanthomonas/*drug effects ; Zinc/*metabolism ; }, abstract = {Ternary solution (TSOL) is a novel Zn chelate-based systemic antimicrobial formulation designed for treating citrus bacterial pathogens 'Candidatus Liberibacter asiaticus' and Xanthomonas citri subsp. citri. TSOL is a component of MS3T, a novel multifunctional surface/sub-surface/systemic therapeutic formulation. Antimicrobial activity of TSOL was compared with the antimicrobial compound ZnO against X. citri subsp. citri and 'Ca. L. asiaticus' surrogate Liberibacter crescens in batch cultures. X. citri subsp. citri and L. crescens were also introduced into microfluidic chambers, and the inhibitory action of TSOL against biofilm formation was evaluated. The minimum inhibitory concentration of TSOL for both X. citri subsp. citri and L. crescens was 40ppm. TSOL was bactericidal to X. citri subsp. citri and L. crescens above 150 ppm and 200 ppm, respectively. On the contrary, ZnO was more effective as a bactericidal agent against L. crescens than X. citri subsp. citri. TSOL was more effective in controlling growth and biofilm formation of X. citri subsp. citri in batch cultures compared to ZnO. Time-lapse video imaging microscopy showed that biofilm formation of X. citri subsp. citri was inhibited in microfluidic chambers treated with 60 ppm TSOL. TSOL also inhibited further growth of already formed X. citri subsp. citri and L. crescens biofilms in microfluidic chambers. Leaf spraying of TSOL showed higher plant uptake and systemic movement in citrus (Citrus reshni) plants compared to that of ZnO, suggesting that TSOL is a promising antimicrobial compound to control vascular plant pathogens such as 'Ca. L. asiaticus'.}, } @article {pmid31233528, year = {2019}, author = {Soler-Arango, J and Figoli, C and Muraca, G and Bosch, A and Brelles-Mariño, G}, title = {The Pseudomonas aeruginosa biofilm matrix and cells are drastically impacted by gas discharge plasma treatment: A comprehensive model explaining plasma-mediated biofilm eradication.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0216817}, pmid = {31233528}, issn = {1932-6203}, mesh = {Atmospheric Pressure ; Biofilms/*drug effects/growth & development ; *Models, Biological ; Plasma Gases/*pharmacology ; Pseudomonas aeruginosa/*cytology/drug effects/*physiology ; Time Factors ; }, abstract = {Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P. aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P. aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.}, } @article {pmid31233504, year = {2019}, author = {MacKenzie, KD and Wang, Y and Musicha, P and Hansen, EG and Palmer, MB and Herman, DJ and Feasey, NA and White, AP}, title = {Parallel evolution leading to impaired biofilm formation in invasive Salmonella strains.}, journal = {PLoS genetics}, volume = {15}, number = {6}, pages = {e1008233}, pmid = {31233504}, issn = {1553-7404}, mesh = {Africa/epidemiology ; Biofilms/growth & development ; *Biological Evolution ; Child ; Gastroenteritis/epidemiology/*genetics/microbiology ; Humans ; Phylogeny ; Polymorphism, Single Nucleotide/genetics ; Salmonella Infections/*genetics/microbiology/transmission ; Salmonella typhimurium/*genetics/pathogenicity ; Trans-Activators/genetics ; }, abstract = {Pathogenic Salmonella strains that cause gastroenteritis are able to colonize and replicate within the intestines of multiple host species. In general, these strains have retained an ability to form the rdar morphotype, a resistant biofilm physiology hypothesized to be important for Salmonella transmission. In contrast, Salmonella strains that are host-adapted or even host-restricted like Salmonella enterica serovar Typhi, tend to cause systemic infections and have lost the ability to form the rdar morphotype. Here, we investigated the rdar morphotype and CsgD-regulated biofilm formation in two non-typhoidal Salmonella (NTS) strains that caused invasive disease in Malawian children, S. Typhimurium D23580 and S. Enteritidis D7795, and compared them to a panel of NTS strains associated with gastroenteritis, as well as S. Typhi strains. Sequence comparisons combined with luciferase reporter technology identified key SNPs in the promoter region of csgD that either shut off biofilm formation completely (D7795) or reduced transcription of this key biofilm regulator (D23580). Phylogenetic analysis showed that these SNPs are conserved throughout the African clades of invasive isolates, dating as far back as 80 years ago. S. Typhi isolates were negative for the rdar morphotype due to truncation of eight amino acids from the C-terminus of CsgD. We present new evidence in support of parallel evolution between lineages of nontyphoidal Salmonella associated with invasive disease in Africa and the archetypal host-restricted invasive serovar; S. Typhi. We hypothesize that the African invasive isolates are becoming human-adapted and 'niche specialized' with less reliance on environmental survival, as compared to gastroenteritis-causing isolates.}, } @article {pmid31232165, year = {2019}, author = {Wang, Y and Wang, Y and Liu, B and Wang, S and Li, J and Gong, S and Sun, L and Yi, L}, title = {pdh modulate virulence through reducing stress tolerance and biofilm formation of Streptococcus suis serotype 2.}, journal = {Virulence}, volume = {10}, number = {1}, pages = {588-599}, pmid = {31232165}, issn = {2150-5608}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Female ; Gene Expression Regulation, Bacterial ; Mice ; *Oxidative Stress ; Pyruvate Dehydrogenase Complex/*genetics ; Serogroup ; Specific Pathogen-Free Organisms ; Streptococcus suis/enzymology/*genetics/*pathogenicity ; Virulence ; }, abstract = {Streptococcus suis serotype 2 (S. suis 2) is a zoonotic pathogen. It causes meningitis, arthritis, pneumonia and sepsis in pigs, leading to extremely high mortality, which seriously affects public health and the development of the pig industry. Pyruvate dehydrogenase (PDH) is an important sugar metabolism enzyme that is widely present in microorganisms, mammals and higher plants. It catalyzes the irreversible oxidative decarboxylation of pyruvate to acetyl-CoA and reduces NAD+ to NADH. In this study, we found that the virulence of the S. suis ZY05719 sequence type 7 pdh deletion strain (Δpdh) was significantly lower than the wild-type strain (WT) in the mouse infection model. The distribution of viable bacteria in the blood and organs of mice infected with the Δpdh was significantly lower than those infected with WT. Bacterial survival rates were reduced in response to temperature stress, salt stress and oxidative stress. Additionally, compared to WT, the ability to adhere to and invade PK15 cells, biofilm formation and stress resistance of Δpdh were significantly reduced. Moreover, real-time PCR results showed that pdh deletion reduced the expression of multiple adhesion-related genes. However, there was no significant difference in the correlation biological analysis between the complemented strain (CΔpdh) and WT. Moreover, the survival rate of Δpdh in RAW264.7 macrophages was significantly lower than that of the WT strain. This study shows that PDH is involved in the pathogenesis of S. suis 2 and reduction in virulence of Δpdh may be related to the decreased ability to resist stress of the strain.}, } @article {pmid31232051, year = {2019}, author = {Perkowski, K and Baltaza, W and Conn, DB and Marczyńska-Stolarek, M and Chomicz, L}, title = {Examination of oral biofilm microbiota in patients using fixed orthodontic appliances in order to prevent risk factors for health complications.}, journal = {Annals of agricultural and environmental medicine : AAEM}, volume = {26}, number = {2}, pages = {231-235}, doi = {10.26444/aaem/105797}, pmid = {31232051}, issn = {1898-2263}, mesh = {Adolescent ; Bacteria/classification/genetics/isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; Child ; Female ; Humans ; Male ; Microbiota ; Mouth/*microbiology ; Oral Hygiene ; Orthodontic Appliances, Fixed/*microbiology ; Poland ; Young Adult ; }, abstract = {INTRODUCTION AND OBJECTIVE: In recent decades the use of orthodontic appliances in Poland has increased; however, data on their influence on changes of components of the microbiome connected with oral biofilm are scarce. The objective of this study was to evaluate oral microbiota in terms of their role as risk factors for health complications.

MATERIAL AND METHODS: The study included 100 patients treated with removable or fixed appliances. Oral hygiene and gingival health were determined, and periodontal swabs taken from each patient for parasitological, bacteriological and mycological microscopic and in vitro examinations.

RESULTS: Oral protists and various pathogenic and opportunistic bacterial and fungal strains were identified in the superficial layer of biofilm. A higher prevalence of bacteria, Enterococcus faecalis, E. faecium, Staphylococcus aureus and Escherichia coli, and various strains of yeast-like fungi from the Candida albicans group, occurred in patients treated with the fixed appliance than in those using a removable appliance or not treated orthodontically. In some periodontal samples from patients treated with fixed appliances, cysts of the Acanthamoeba spp. were found.

CONCLUSIONS: The use of orthodontic appliances alters the status of the oral cavity; it has impact on the colonization of oral biofilm by opportunistic/pathogenic strains, and increases the risk of their dissemination to various human tissues and organs. Pretreatment examination of oral microbiome, its monitoring particularly during treatment with fixed appliances, and preventive elimination of the potentially pathogenic strains to avoid health complications, are highly recommended, especially in patients with impaired immunity.}, } @article {pmid31231348, year = {2019}, author = {Singh, VK and Mishra, A and Jha, B}, title = {3-Benzyl-Hexahydro-Pyrrolo[1,2-a]Pyrazine-1,4-Dione Extracted From Exiguobacterium indicum Showed Anti-biofilm Activity Against Pseudomonas aeruginosa by Attenuating Quorum Sensing.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1269}, pmid = {31231348}, issn = {1664-302X}, abstract = {Bacterial cell-to-cell communication promotes biofilm formation and can potentially lead to multidrug resistance development. Quorum sensing inhibition (QSI) is an effective and widely employed strategy against biofilm formation. The extract from Exiguobacterium indicum SJ16, a gram-positive bacterium, isolated from the rhizosphere of Cyperus laevigatus showed significant anti-quorum sensing activity (about 99%) against the reference Chromobacterium violaceum CV026 strain without exerting any antibacterial effect. The potentially active QSI compound identified in the SJ16 extract was 3-Benzyl-hexahydro-pyrrolo[1, 2-a]pyrazine-1,4-dione. The SJ16 extract containing this active compound showed significant anti-quorum sensing activity against a model quorum sensing bacterium strain Pseudomonas aeruginosa PAO1 and a clinical isolate P. aeruginosa PAH by preventing biofilm formation without attenuating the cell growth within the biofilm. More specifically, the SJ16 extract changed the topography and architecture of the biofilm, thus preventing bacterial adherence and further development of the biofilm. Furthermore, it decreased virulence factors (rhamnolipid and pyocyanin), the bacterial motility, as well as the elastase, and protease activities in P. aeruginosa. Microarray analysis revealed the differential expression of quorum sensing regulatory genes. Based on these results, we herein propose a hypothetical model, characterizing the role of this QSI agent in the transcriptional regulation of quorum sensing in P. aeruginosa PAO1, demonstrating that this compound has significant drug-development potential. Further research is required to delineate its possible applications in therapeutics in the context of biofilm forming bacterial infections.}, } @article {pmid31231324, year = {2019}, author = {Pathirana, RU and McCall, AD and Norris, HL and Edgerton, M}, title = {Filamentous Non-albicans Candida Species Adhere to Candida albicans and Benefit From Dual Biofilm Growth.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1188}, pmid = {31231324}, issn = {1664-302X}, abstract = {Non-albicans Candida species (NACS) are often isolated along with Candida albicans in cases of oropharyngeal candidiasis. C. albicans readily forms biofilms in conjunction with other oral microbiota including both bacteria and yeast. Adhesion between species is important to the establishment of these mixed biofilms, but interactions between C. albicans and many NACS are not well-characterized. We adapted a real-time flow biofilm model to study adhesion interactions and biofilm establishment in C. albicans and NACS in mono- and co-culture. Out of five NACS studied, only the filamenting species C. tropicalis and C. dubliniensis were capable of adhesion with C. albicans, while C. parapsilosis, C. lusitaniae, and C. krusei were not. Over the early phase (0-4 h) of biofilm development, both mono- and co-culture followed similar kinetics of attachment and detachment events, indicating that initial biofilm formation is not influenced by inter-species interactions. However, the NACS showed a preference for inter-species cell-cell interactions with C. albicans, and at later time points (5-11 h) we found that dual-species interactions impacted biofilm surface coverage. Dual-species biofilms of C. tropicalis and C. albicans grew more slowly than C. albicans alone, but achieved higher surface coverage than C. tropicalis alone. Biofilms of C. dubliniensis with C. albicans increased surface coverage more rapidly than either species alone. We conclude that dual culture biofilm of C. albicans with C. tropicalis or C. dubliniensis offers a growth advantage for both NACS. Furthermore, the growth and maintenance, but not initial establishment, of dual-species biofilms is likely facilitated by interspecies cell-cell adherence.}, } @article {pmid31230907, year = {2019}, author = {Wang, J and Liu, Q and Ma, S and Hu, H and Wu, B and Zhang, XX and Ren, H}, title = {Distribution characteristics of N-acyl homoserine lactones during the moving bed biofilm reactor biofilm development process: Effect of carbon/nitrogen ratio and exogenous quorum sensing signals.}, journal = {Bioresource technology}, volume = {289}, number = {}, pages = {121591}, doi = {10.1016/j.biortech.2019.121591}, pmid = {31230907}, issn = {1873-2976}, mesh = {*Acyl-Butyrolactones ; Biofilms ; Carbon ; Nitrogen ; *Quorum Sensing ; }, abstract = {Carbon/nitrogen (C/N) ratios play an important role in biological wastewater treatment processes, with quorum sensing (QS) coordinating biological group behaviors. However, the relationship between them remains unclear. This study investigated the effects of varying C/N ratios and exogenous QS signals on the distribution characteristics of AHLs in Moving Bed Biofilm Reactors during the biofilm development process. Results show that C10-HSL and C12-HSL were the dominant AHLs, with the highest concentrations observed in the reactor with a C/N ratio of 10, followed by C/N ratios of 20 and 4. With varying C/N ratios, the biofilm microbial community structure changed significantly, which may contribute to significant differences in the distribution of AHLs. Furthermore, with the addition of a QS strain Sphingomonas rubra sp. nov., the pollutant removal efficiency of the reactor was not significantly improved and a reversible change in community composition was temporarily observed.}, } @article {pmid31229548, year = {2019}, author = {Bellich, B and Distefano, M and Syrgiannis, Z and Bosi, S and Guida, F and Rizzo, R and Brady, JW and Cescutti, P}, title = {The polysaccharide extracted from the biofilm of Burkholderia multivorans strain C1576 binds hydrophobic species and exhibits a compact 3D-structure.}, journal = {International journal of biological macromolecules}, volume = {136}, number = {}, pages = {944-950}, pmid = {31229548}, issn = {1879-0003}, support = {R01 GM123283/GM/NIGMS NIH HHS/United States ; }, mesh = {Alkanes/*chemistry ; *Biofilms ; Burkholderia/*chemistry/*physiology ; Carbohydrate Conformation ; Dimerization ; *Hydrophobic and Hydrophilic Interactions ; Polysaccharides, Bacterial/*chemistry/*isolation & purification ; Surface Plasmon Resonance ; }, abstract = {Microorganisms often grow in communities called biofilms where cells are imbedded in a complex self-produced biopolymeric matrix composed mainly of polysaccharides, proteins, and DNA. This matrix, together with cell proximity, confers many advantages to these microbial communities, but also constitutes a serious concern when biofilms develop in human tissues or on implanted prostheses. Although polysaccharides are considered the main constituents of the matrices, their specific role needs to be clarified. We have investigated the chemical and morphological properties of the polysaccharide extracted from biofilms produced by the C1576 reference strain of the opportunistic pathogen Burkholderia multivorans, which causes lung infections in cystic fibrosis patients. The aim of the present study is the definition of possible interactions of the polysaccharide and the three-dimensional conformation of its chain within the biofilm matrix. Surface plasmon resonance experiments confirmed the ability of the polysaccharide to bind hydrophobic molecules, due to the presence of rhamnose dimers in its primary structure. In addition, atomic force microscopy studies evidenced an extremely compact three-dimensional structure of the polysaccharide which may form aggregates, suggesting a novel view of its structural role into the biofilm matrix.}, } @article {pmid31229099, year = {2019}, author = {Cruzado-Bravo, MLM and Silva, NCC and Rodrigues, MX and Silva, GOE and Porto, E and Sturion, GL}, title = {Phenotypic and genotypic characterization of Staphylococcus spp. isolated from mastitis milk and cheese processing: Study of adherence and biofilm formation.}, journal = {Food research international (Ottawa, Ont.)}, volume = {122}, number = {}, pages = {450-460}, doi = {10.1016/j.foodres.2019.04.017}, pmid = {31229099}, issn = {1873-7145}, mesh = {Animals ; *Bacterial Adhesion ; Biofilms ; Cheese/*microbiology ; Colony Count, Microbial ; Culture Media ; Food Contamination ; *Food Handling ; Food Microbiology ; Genes, Bacterial ; Genotype ; Microscopy, Electron, Scanning ; Milk/*microbiology ; Phenotype ; Polypropylenes/chemistry ; Stainless Steel/chemistry ; Staphylococcus/*isolation & purification/metabolism ; Temperature ; }, abstract = {The aim of this study was to identify the phenotypic and genotypic profiles of Staphylococcus spp. isolated from mastitis milk and cheese processing plant.To evaluate the biofilm production of wild-type strains on contact surfaces by testing different factors through adhered cells and biofilm quantifications, finally, these biofilms were observed by Scanning Electron Microscopy (SEM). Congo red agar (CRA) plate method was used to identify slime production by strains. Screening of genes encoding adhesion factors and biofilm formation was carried out using PCR. After strains selection, adhesion and biofilm assays were designed testing different times (12, 48, 96 h), strains (n = 13), contact surfaces (stainless steel and polypropylene), and temperatures (5 °C and 25 °C); and then, bacterial count and crystal violet staining were conducted. Relative frequencies of positive on CRA and genes presence were determined, and Friedman test was applied for bacterial counts and OD values. Additionally, significant factors (P ≤ .05) were subjected to multiple comparisons using the Nemenyi test. The slime production in CRA was observed by visual inspection in 38.7% of strains. A large distribution of genes was described among strains, implying a high variability of genotypic profiles. Moreover, relative frequencies of CRA positive and gene presence were described. The developed assay showed that the strain, temperature, contact surface, were significant for both variables. The SEM corroborated the findings, showing greater biofilm formation on stainless steel at 25 °C. Thus, it is essential to highlight the importance of temperature control and material with low superficial energy to avoid biofilm formation by staphylococci.}, } @article {pmid31228833, year = {2019}, author = {Wang, J and Liu, Q and Hu, H and Wu, B and Zhang, XX and Ren, H}, title = {Insight into mature biofilm quorum sensing in full-scale wastewater treatment plants.}, journal = {Chemosphere}, volume = {234}, number = {}, pages = {310-317}, doi = {10.1016/j.chemosphere.2019.06.007}, pmid = {31228833}, issn = {1879-1298}, mesh = {Acyl-Butyrolactones/*analysis/metabolism ; *Biofilms ; Carbon ; China ; Nitrogen ; *Quorum Sensing ; Temperature ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {Quorum sensing (QS) has been thoroughly investigated during initial biofilm formation stages, while the role of QS in mature biofilms has received little research attention. This study assessed QS in 22 biofilm samples from full-scale wastewater treatment plants in China. Results showed that the concentration of acyl-homoserine lactones (AHLs) in various biofilm bound forms, ranged from 15.63 to 609.76 ng/g. The highest concentration of AHLs was found in the tightly bound biofilm fraction, while the lowest concentrations were observed in the surface biofilm fraction. Environmental variables, C/N ratio and temperature, were found to be significant factors influencing biofilm AHL distribution (p < 0.01). Higher C/N ratios (ranging from 3 to 12) and low temperatures contributed to the higher concentration of AHLs in biofilms. Dominant AHLs (C10-HSL and C12-HSL) were significantly associated with biofilm activity (R[2] = 0.98/0.97, p < 0.05), with the tightly bound biofilm fraction (TB-biofilm) presenting the highest activity (ATP concentration). Biofilm aging and re-formation processes were more active in the surface biofilm layer (S-biofilm), while the stable structure of the TB-biofilm layer which is attached to the surface of bio-carriers ensures high biofilm activity. This study furthers our understanding of the roles of AHLs in the regulation of mature biofilm activities.}, } @article {pmid31228790, year = {2019}, author = {Luo, JH and Wu, M and Liu, J and Qian, G and Yuan, Z and Guo, J}, title = {Microbial chromate reduction coupled with anaerobic oxidation of methane in a membrane biofilm reactor.}, journal = {Environment international}, volume = {130}, number = {}, pages = {104926}, doi = {10.1016/j.envint.2019.104926}, pmid = {31228790}, issn = {1873-6750}, mesh = {Anaerobiosis ; Archaea/chemistry/classification/*metabolism ; Bacteria/chemistry/classification/*metabolism ; *Biofilms ; *Bioreactors ; Chromates/*metabolism ; In Situ Hybridization, Fluorescence ; Methane ; *Microbial Consortia ; Nitrates ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; }, abstract = {It has been reported that microbial reduction of sulfate, nitrite/nitrate and iron/manganese could be coupled with anaerobic oxidation of methane (AOM), which plays a significant role in controlling methane emission from anoxic niches. However, little is known about microbial chromate (Cr(VI)) reduction coupling with AOM. In this study, a microbial consortium was enriched via switching nitrate dosing to chromate feeding as the sole electron acceptor under anaerobic condition in a membrane biofilm reactor (MBfR), in which methane was continuously provided as the electron donor through bubble-less hollow fiber membranes. According to long-term reactor operation and chromium speciation analysis, soluble chromate could be reduced into Cr(III) compounds by using methane as electron donor. Fluorescence in situ hybridization and high-throughput 16S rRNA gene amplicon profiling further indicated that after feeding chromate Candidatus 'Methanoperedens' (a known nitrate-dependent anaerobic methane oxidation archaeon) became sole anaerobic methanotroph in the biofilm, potentially responsible for the chromate bio-reduction driven by methane. Two potential pathways of the microbial AOM-coupled chromate reduction were proposed: (i) Candidatus 'Methanoperedens' independently utilizes chromate as electron acceptor to form Cr(III) compounds, or (ii) Candidatus 'Methanoperedens' oxidizes methane to generate intermediates or electrons, which will be utilized to reduce chromate to Cr(III) compounds by unknown chromate reducers synergistically. Our findings suggest a possible link between the biogeochemical chromium and methane cycles.}, } @article {pmid31228542, year = {2019}, author = {Cardoso, MH and Santos, VPM and Costa, BO and Buccini, DF and Rezende, SB and Porto, WF and Santos, MJ and Silva, ON and Ribeiro, SM and Franco, OL}, title = {A short peptide with selective anti-biofilm activity against Pseudomonas aeruginosa and Klebsiella pneumoniae carbapenemase-producing bacteria.}, journal = {Microbial pathogenesis}, volume = {135}, number = {}, pages = {103605}, doi = {10.1016/j.micpath.2019.103605}, pmid = {31228542}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Bacterial Proteins ; Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Drug Resistance, Bacterial/drug effects ; Erythrocytes/drug effects ; Fibroblasts/drug effects ; Humans ; Klebsiella pneumoniae/*drug effects ; Mice ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Dynamics Simulation ; Plasmodium chabaudi/chemistry ; Pseudomonas aeruginosa/*drug effects ; beta-Lactamases ; }, abstract = {Biofilm-related infections represent an enormous clinical challenge nowadays. In this context, diverse studies are underway to develop effective antimicrobial agents targeting bacterial biofilms. Here, we describe the antibacterial and anti-biofilm activities of a short, cationic peptide named R5F5, obtained from sliding-window analysis based on a peptide (PcDBS1R5) derived from Plasmodium chabaudi. Ten fragments were generated (R5F1 to F10) and submitted to initial antibacterial assays against Pseudomonas aeruginosa. As a result, R5F5 showed the highest antimicrobial activity. We therefore carried out further antibacterial and anti-biofilm assays against P. aeruginosa and Klebsiella pneumoniae carbapenemase-producing bacterial strains. R5F5 revealed selective anti-biofilm activity, as the peptide inhibited >60% biofilm formation in all cases from 8 to 64 μg·mL[-1]. Moreover, R5F5 was not hemolytic against mice erythrocytes at 640 μg mL[-1]. Cytotoxic effects on human lung fibroblast cells were not detected at 160 μg·mL[-1]. Structural studies revealed that R5F5 presents random coil conformations in water and 50% 2,2,2-trifluoroethanol (TFE)/water (v/v), whereas amphipathic, extended conformations were observed in contact with sodium dodecyl sulfate (SDS) micelles. Thus, here we report a novel peptide with selective anti-biofilm activity against susceptible and resistant bacterial strains, with no toxicity toward mammalian cells and that adopts a stable structure in anionic environment.}, } @article {pmid31226983, year = {2019}, author = {Sánchez, MC and Ribeiro-Vidal, H and Esteban-Fernández, A and Bartolomé, B and Figuero, E and Moreno-Arribas, MV and Sanz, M and Herrera, D}, title = {Antimicrobial activity of red wine and oenological extracts against periodontal pathogens in a validated oral biofilm model.}, journal = {BMC complementary and alternative medicine}, volume = {19}, number = {1}, pages = {145}, pmid = {31226983}, issn = {1472-6882}, support = {ALIBIRD-CM S2013/ABI-2728//Comunidad de Madrid/ ; AGL2015-64522-C2-R project//Spanish MINECO/ ; }, mesh = {Aggregatibacter actinomycetemcomitans/drug effects/physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fusobacterium nucleatum/*drug effects/physiology ; Humans ; Periodontal Diseases/*microbiology ; Plant Extracts/*pharmacology ; Polyphenols/pharmacology ; Porphyromonas gingivalis/drug effects/physiology ; Seeds/chemistry ; Vitis/chemistry ; Wine/*analysis ; }, abstract = {BACKGROUND: Previous research findings support an antimicrobial effect of polyphenols against a variety of pathogens, but there is no evidence of this effect against periodontal pathogens in complex biofilms. The purpose of this study was to evaluate the antimicrobial activity of red wine and oenological extracts, rich in polyphenols, against the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and total bacteria growing in an in vitro oral biofilm static model.

METHODS: A previously validated biofilm model, including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, F. nucleatum, P. gingivalis and A. actinomycetemcomitans was developed on sterile hydroxyapatite discs. Red wine (and dealcoholized wine), and two polyphenols-rich extracts (from wine and grape seeds) were applied to 72 h biofilms by dipping the discs during 1 and 5 min in the wine solutions and during 30 s and 1 min in the oenological extracts. Resulting biofilms were analyzed by confocal laser scanning microscopy and viable bacteria (colony forming units/mL) were measured by quantitative polymerase chain reaction combined with propidium monoazide. A generalized linear model was constructed to determine the effect of the tested products on the viable bacterial counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, as well on the total number of viable bacteria.

RESULTS: The results showed that red wine and dealcoholized red wine caused reduction in viability of total bacteria within the biofilm, with statistically significant reductions in the number of viable P. gingivalis after 1 min (p = 0.008) and in A. actinomycetemcomitans after 5 min of exposure (p = 0.011) with red wine. No evidence of relevant antibacterial effect was observed with the oenological extracts, with statistically significant reductions of F. nucleatum after 30 s of exposure to both oenological extracts (p = 0.001).

CONCLUSIONS: Although moderate, the antimicrobial impact observed in the total bacterial counts and counts of A. actinomycetemcomitans, P. gingivalis and F. nucleatum, encourage further investigations on the potential use of these natural products in the prevention and treatment of periodontal diseases.}, } @article {pmid31226270, year = {2019}, author = {Short, B and Brown, J and Delaney, C and Sherry, L and Williams, C and Ramage, G and Kean, R}, title = {Candida auris exhibits resilient biofilm characteristics in vitro: implications for environmental persistence.}, journal = {The Journal of hospital infection}, volume = {103}, number = {1}, pages = {92-96}, doi = {10.1016/j.jhin.2019.06.006}, pmid = {31226270}, issn = {1532-2939}, mesh = {Biofilms/drug effects/*growth & development ; Candida/drug effects/*growth & development ; Disinfectants/pharmacology ; *Environmental Microbiology ; Microbial Viability/*drug effects ; Sodium Hypochlorite/pharmacology ; }, abstract = {Surfaces within healthcare play a key role in the transmission of drug-resistant pathogens. Candida auris is an emerging multidrug-resistant yeast which can survive for prolonged periods on environmental surfaces. Here we show that the ability to form cellular aggregates increases survival after 14 days, which coincides with the upregulation of biofilm-associated genes. Additionally, the aggregating strain demonstrated tolerance to clinical concentrations of sodium hypochlorite and remained viable 14 days post treatment. The ability of C. auris to adhere to and persist on environmental surfaces emphasizes our need to better understand the biology of this fungal pathogen.}, } @article {pmid31222089, year = {2019}, author = {Ramos-Vivas, J and Chapartegui-González, I and Fernández-Martínez, M and González-Rico, C and Fortún, J and Escudero, R and Marco, F and Linares, L and Montejo, M and Aranzamendi, M and Muñoz, P and Valerio, M and Aguado, JM and Resino, E and Ahufinger, IG and Vega, AP and Martínez-Martínez, L and Fariñas, MC and , }, title = {Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {8928}, pmid = {31222089}, issn = {2045-2322}, mesh = {Bacterial Infections/microbiology ; *Biofilms ; *Drug Resistance, Multiple, Bacterial/genetics ; Enterobacteriaceae/drug effects/*isolation & purification ; Humans ; *Organ Transplantation ; }, abstract = {Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant bacteria (MDR). In this study, the biofilm-forming capability of 209 MDR strains (Escherichia coli n = 106, Klebsiella pneumoniae n = 78, and Enterobacter spp. n = 25) isolated from rectal swabs in the first 48 hours before or after kidney (93 patients), liver (60 patients) or kidney/pancreas transplants (5 patients) were evaluated by using a microplate assay. Thirty-nine strains were isolated before transplant and 170 strains were isolated post-transplant. Overall, 16% of E. coli strains, 73% of K. pneumoniae strains and 4% Enterobacter strains showed moderate or strong biofilm production. Nine strains isolated from infection sites after transplantation were responsible of infections in the first month. Of these, 4 K. pneumoniae, 1 E. coli and 1 Enterobacter spp. strains isolated pre-transplant or post-transplant as colonizers caused infections in the post-transplant period. Our results suggest that in vitro biofilm formation could be an important factor for adhesion to intestine and colonization in MDR K. pneumoniae strains in SOT recipients, but this factor appears to be less important for MDR E. coli and Enterobacter spp.}, } @article {pmid31222015, year = {2019}, author = {Tassinari, E and Duffy, G and Bawn, M and Burgess, CM and McCabe, EM and Lawlor, PG and Gardiner, G and Kingsley, RA}, title = {Microevolution of antimicrobial resistance and biofilm formation of Salmonella Typhimurium during persistence on pig farms.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {8832}, pmid = {31222015}, issn = {2045-2322}, support = {BB/R012504/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N007964/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M025489/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10348/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/F/000PR10349/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Biofilms/*growth & development ; *Biological Evolution ; Drug Resistance, Bacterial/*genetics ; Drug Resistance, Multiple, Bacterial/genetics ; *Farms ; Genome, Bacterial ; Genotype ; Phylogeny ; Salmonella typhimurium/*genetics ; Sus scrofa ; }, abstract = {Salmonella Typhimurium and its monophasic variant S. 4,[5],12:i:- are the dominant serotypes associated with pigs in many countries. We investigated their population structure on nine farms using whole genome sequencing, and their genotypic and phenotypic variation. The population structure revealed the presence of phylogenetically distinct clades consisting of closely related clones of S. Typhimurium or S. 4,[5],12:i:- on each pig farm, that persisted between production cycles. All the S. 4,[5],12:i:- strains carried the Salmonella genomic island-4 (SGI-4), which confers resistance to heavy metals, and half of the strains contained the mTmV prophage, harbouring the sopE virulence gene. Most clonal groups were highly drug resistant due to the presence of multiple antimicrobial resistance (AMR) genes, and two clades exhibited evidence of recent on-farm plasmid-mediated acquisition of additional AMR genes, including an IncHI2 plasmid. Biofilm formation was highly variable but had a strong phylogenetic signature. Strains capable of forming biofilm with the greatest biomass were from the S. 4,[5],12:i:- and S. Typhimurium DT104 clades, the two dominant pandemic clones found over the last 25 years. On-farm microevolution resulted in enhanced biofilm formation in subsequent production cycle.}, } @article {pmid31220767, year = {2019}, author = {Zhong, H and Wang, H and Tian, Y and Liu, X and Yang, Y and Zhu, L and Yan, S and Liu, G}, title = {Treatment of polluted surface water with nylon silk carrier-aerated biofilm reactor (CABR).}, journal = {Bioresource technology}, volume = {289}, number = {}, pages = {121617}, doi = {10.1016/j.biortech.2019.121617}, pmid = {31220767}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; China ; Nylons ; Silk ; Waste Disposal, Fluid ; *Water Purification ; }, abstract = {Carrier aerated biofilm reactor (CABR) with nylon silk as the biofilm growth carrier was constructed to treatment of polluted surface water, which could improve the practical application in comparison with MABR process. The results show that CABR process can effectively improve the self-purification capacity of the polluted surface water, efficient removal of COD and NH3-N, making water quality achieve the level V of Environmental Quality Standards for Surface Water (GB 3838-2002, China). Modified nylon silk can alter the community structures and increase bacteria during CABR process operation. Large pore size of nylon silk leads to the formation of special biofilm structure in CABR. Extracellular polymer (EPS) and membrane fouling resistance distribution indicated that the nylon silk fouling control ability of CABR reactor is much higher than that of membrane-aerated biofilm reactors (MABR). The results show that the CABR process can effectively purify surface water and improve the practical application.}, } @article {pmid31220446, year = {2019}, author = {Lee, TH and Jung, MK and Kim, TK and Pack, CG and Park, YK and Kim, SO and Park, DH}, title = {Safety and efficacy of a metal stent covered with a silicone membrane containing integrated silver particles in preventing biofilm and sludge formation in endoscopic drainage of malignant biliary obstruction: a phase 2 pilot study.}, journal = {Gastrointestinal endoscopy}, volume = {90}, number = {4}, pages = {663-672.e2}, doi = {10.1016/j.gie.2019.06.007}, pmid = {31220446}, issn = {1097-6779}, mesh = {Aged ; Ampulla of Vater ; Bile ; *Biofilms ; Carcinoma, Hepatocellular/complications ; Cholangitis/epidemiology ; Cholestasis/etiology/*surgery ; Common Bile Duct Neoplasms/complications ; Drainage/instrumentation ; Endoscopy, Digestive System ; Female ; Gallbladder Neoplasms/complications ; Humans ; Liver Neoplasms/complications ; Male ; *Metal Nanoparticles ; Microscopy, Electron, Scanning ; Middle Aged ; Palliative Care ; Pancreatic Neoplasms/complications ; Pancreatitis/epidemiology ; Pilot Projects ; Postoperative Complications/epidemiology ; Prosthesis Failure ; *Self Expandable Metallic Stents ; *Silicones ; *Silver ; }, abstract = {BACKGROUND AND AIMS: Membrane-covered self-expandable metal stents (SEMSs) have been developed to prolong the patency of stents by reducing tissue hyperplasia or tumor ingrowth. However, their effectiveness is attenuated by stent clogging as a result of biofilm formation on the inner surface of the membrane. The aim of this pilot study was to evaluate the efficacy and safety of SEMSs covered with a silicone membrane containing integrated silver particles (Ag-P) in malignant distal biliary obstruction.

METHODS: Twenty-four patients who underwent SEMS placement because of malignant distal biliary obstruction were enrolled in this single-center pilot study. The main outcomes were technical success, clinical success, adverse events, stent patency, and survival.

RESULTS: The technical and clinical success rates were 100% and 91.7% (22 of 24), respectively. The rates of early and late adverse events were 22.7% and 36.4%, respectively. The primary reintervention rate was 27.3% (6 of 22). Only 1 case involving stent malfunction was associated with sludge impaction. Median stent patency was 179 days. During follow-up, there were no serious adverse events or mortality related to the stents or Ag-P. Serum and urine silver concentrations before and after stent placement and at 32 weeks after placement did not differ. All serum and urine silver concentrations were <3 μg/L (3 ppb) and 5 μg/L (5 ppb), respectively.

CONCLUSIONS: SEMSs covered with a silicone membrane containing integrated Ag-Ps may be effective and safe in malignant distal biliary obstruction. Stent dysfunction related to sludge impaction may be less frequent using this new stent. (Clinical Research Information Service identifier: KCT 0002310.).}, } @article {pmid31219091, year = {2019}, author = {George, J and Halami, PM}, title = {Presence of extracellular DNA & protein in biofilm formation by gentamicin-resistant Lactobacillus plantarum.}, journal = {The Indian journal of medical research}, volume = {149}, number = {2}, pages = {257-262}, pmid = {31219091}, issn = {0971-5916}, mesh = {Anti-Bacterial Agents/adverse effects/therapeutic use ; Biofilms/*drug effects/growth & development ; DNA, Bacterial/drug effects/*genetics ; Drug Resistance, Bacterial/*genetics ; Endopeptidase K/pharmacology ; Gentamicins/adverse effects/therapeutic use ; Humans ; Lactobacillus plantarum/drug effects/*genetics/growth & development ; Probiotics/metabolism ; }, abstract = {BACKGROUND & OBJECTIVES: Bacterial biofilms a multi-layered defence, comprise extracellular DNA (eDNA) and proteins, protect bacteria from harmful environment and nutrient limitation and utilize the mutual benefits within a community. Bacterial biofilms also defend bacteria from harsh environments such as antibiotic treatment. This leads to poor antibiotic penetration, slow growth, adaptive stress responses, and formation of persister cells. This study was done to determine the relation of antibiotic resistance deciphered by the biofilms in Lactobacillus plantarum, a lactic acid bacteria (LAB) with probiotic significance.

METHODS: The gentamicin-resistant L. plantarum isolates were allowed to form biofilms and subjected to DNase I and proteinase K treatment. The optical density (OD) values were recorded for the biofilm assay and the cell count for the number of viable cells was taken for the control and the test samples. Percentage reduction was calculated based on the difference between the initial and final OD for both the parameters.

RESULTS: The biofilm assay revealed that the native L. plantarum isolates which were phenotypically susceptible, possessed the ability to form biofilms. The OD values were significantly decreased in comparison to the biofilm-forming control culture when these were treated with DNase I and proteinase K.

The study revealed that the biofilms formed by L. plantarum comprised of eDNA and proteins which was evidenced by the reduction in OD values and percentage in comparison to the control upon DNase I and proteinase K treatment. This indicates that the eDNA and biofilm matrix proteins are vital constituents of biofilms and may carry significant risk when coupled with antibiotic resistance.}, } @article {pmid31218543, year = {2020}, author = {Pepoyan, AZ and Manvelyan, AM and Balayan, MH and Galstyan, S and Tsaturyan, VV and Grigoryan, B and Chikindas, ML}, title = {Low-Dose Electron-Beam Irradiation for the Improvement of Biofilm Formation by Probiotic Lactobacilli.}, journal = {Probiotics and antimicrobial proteins}, volume = {12}, number = {2}, pages = {667-671}, doi = {10.1007/s12602-019-09566-1}, pmid = {31218543}, issn = {1867-1314}, mesh = {Biofilms/*radiation effects ; *Food Irradiation ; Lactobacillus acidophilus/*radiation effects ; Lacticaseibacillus rhamnosus/*radiation effects ; Probiotics/*radiation effects ; }, abstract = {The effects of 50-150 gray electron-beam irradiation on the biofilm-formation ability and cell surface hydrophobicity of the commercial strain, Lactobacillus acidophilus DDS®-1, from Lacto-G (a marketed synbiotic formulation) and the putative probiotic, L. rhamnosus Vahe, were evaluated. No significant changes in cell surface hydrophobicity were found after irradiation, while increases in biofilm-formation abilities were documented for both investigated microorganisms 0.22 ± 0.03 vs. 0.149 ± 0.02 (L. rhamnosus Vahe, 150 Gy) and 0.218 ± 0.021 vs. 0.17 ± 0.012 (L. acidophilus DDS®-1, 150 Gy). Given this, the use of electron-beam irradiation (50-100 Gy) for the treatment of L. rhamnosus Vahe and L. acidophilus DDS®-1 cells may be considered in product sterilization, quality improvement, and packaging practices.}, } @article {pmid31218489, year = {2019}, author = {De-la-Pinta, I and Cobos, M and Ibarretxe, J and Montoya, E and Eraso, E and Guraya, T and Quindós, G}, title = {Effect of biomaterials hydrophobicity and roughness on biofilm development.}, journal = {Journal of materials science. Materials in medicine}, volume = {30}, number = {7}, pages = {77}, pmid = {31218489}, issn = {1573-4838}, mesh = {Bacterial Adhesion ; Biocompatible Materials/*chemistry ; Biofilms/*drug effects ; Bioreactors ; Candida albicans ; Equipment Contamination/prevention & control ; Equipment and Supplies/*microbiology ; Escherichia coli ; Hydrophobic and Hydrophilic Interactions ; Polyurethanes ; Pseudomonas aeruginosa ; Staphylococcus epidermidis ; *Surface Properties ; }, abstract = {Most hospitalized patients are carriers of biomedical devices. Infections associated with these devices cause great morbidity and mortality, especially in patients in intensive care units. Numerous strategies have been designed to prevent biofilm development on biodevices. However, biofilm formation is a complex process not fully clarified. In the current study, roughness and hydrophobicity of different biomaterials was analyzed to assess their influences on the biofilm formation of four leading etiological causes of healthcare-associated infections, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis and Candida albicans, using a CDC biofilm reactor. Hydrophobic materials allowed the formation of more abundant and profuse biofilms. Roughness had effect on biofilm formation, but its influence was not significant when material hydrophobicity was considered.}, } @article {pmid31218468, year = {2019}, author = {Stacchi, C and Del Lupo, V and Berton, F and Lombardi, T and Bressan, R and Di Lenarda, R and Lagatolla, C}, title = {Aspergillus fumigatus biofilm formation on different bone substitutes used in maxillary sinus augmentation: an in vitro analysis.}, journal = {International journal of implant dentistry}, volume = {5}, number = {1}, pages = {22}, pmid = {31218468}, issn = {2198-4034}, abstract = {BACKGROUND: Fungus ball (FB) typically affects healthy adults, and Aspergillus fumigatus is the most frequent etiologic agent: iatrogenic factors represent an important issue in FB pathogenesis. Moreover, a recent study suggested a significant association between the use of anorganic bovine bone as sinus grafting material and subsequent development of FB. The aim of the present investigation is to evaluate in vitro eventual differences in the ability of Aspergillus fumigatus to colonize different bone grafting materials and grow on them as biofilm.

FINDINGS: Five different bone substitutes (demineralized bone matrix, anorganic bovine bone, ß-tricalcium phosphate, synthetic nano-hydroxyapatite, and synthetic hydroxyapatite), commonly used in sinus floor augmentation procedures, were inoculated with conidia suspensions of A. fumigatus and incubated at 37 °C for 4 and 8 h, in standardized conditions. Biofilm bound to the different materials underwent quantitative and qualitative analysis by confocal and scanning electron microscopy. A. fumigatus proved to be able to adhere and form biofilm on all the tested bone substitutes. The surface plot representation of the samples displayed some differences in the density of the superficial layer, due to the physical characteristics of the biomaterials. Nevertheless, Kruskal-Wallis test showed no significant differences in biomass amount among the five bone substitutes (p = 0.236 and p = 0.55 after 4 and 8 h adhesion, respectively).

CONCLUSIONS: All the bone substitutes normally used in sinus floor augmentation represent a favorable substrate for fungal growth, due to their physical and chemical characteristics. During sinus floor elevation procedures, Schneiderian membrane integrity should be maintained in order to avoid the exposure of the grafting material at the respiratory environment, with potential risks of fungal colonization.}, } @article {pmid31217919, year = {2019}, author = {Khalifehzadeh, S and Haghanifar, S and Jenabian, N and Kazemi, S and Hajiahmadi, M}, title = {Clinical and radiographic evaluation of applying 1% metformin biofilm with plasma rich in growth factor (PRGF) for treatment of two-wall intrabony periodontal defects: A randomized clinical trial.}, journal = {Journal of dental research, dental clinics, dental prospects}, volume = {13}, number = {1}, pages = {51-56}, pmid = {31217919}, issn = {2008-210X}, abstract = {Background . The ultimate aim of periodontal treatment is to regenerate periodontium and regenerative treatment after that. The aim of this study was to evaluate the effect of PRGF with 1% metformin biofilm in the treatment of two-wall intrabony periodontal defects. Methods . In this clinical trial, 8 patients with moderate chronic periodontitis and two-wall intrabony defect were selected. The defects were assigned to 4 groups: debridement, 1% metformin, PRGF, PRGF and metformin. The parameters of vertical probing depth, vertical clinical attachment level and gingival index were measured at baseline, immediately before surgery, and 3 and 6 months after surgery. In addition, the radiographic changes were evaluated with digital subtraction radiography before and 6 months after surgery. Analysis of the results was performed with repeated measurements, Friedman test and chisquared test. Results . All the groups exhibited improvements in all the clinical parameters after 6 months. Inter-group comparison of GI, CAL and PPD parameters revealed no statistically significant differences. Radiographic changes in the group of 1% metformin with PRGF revealed statistically significant differences compared with other groups; however, there were no statistically significant differences in other groups. Conclusion . Application of PRGF with 1% metformin in intrabony two-wall periodontal defects was effective in improving the clinical parameters but this effect revealed no difference compared with other groups; however, in terms of radiographic changes significant improvements were noted.}, } @article {pmid31217374, year = {2019}, author = {Zhou, G and Peng, H and Wang, YS and Huang, XM and Xie, XB and Shi, QS}, title = {Enhanced synergistic effects of xylitol and isothiazolones for inhibition of initial biofilm formation by Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538.}, journal = {Journal of oral science}, volume = {61}, number = {2}, pages = {255-263}, doi = {10.2334/josnusd.18-0102}, pmid = {31217374}, issn = {1880-4926}, mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; Biofilms ; *Pseudomonas aeruginosa ; Staphylococcus aureus ; Xylitol ; }, abstract = {Bacterial biofilms, formed on biotic or abiotic surfaces, can lead to serious environmental or medical problems. Therefore, it is necessary to find novel antimicrobial agents to combat biofilms, or more effective combinations of existing biocides. In this study, initial biofilms of Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538 in the presence of xylitol or xylitol and isothiazolones were determined using crystal violet staining in 96-well microplates and confocal laser scanning microscopy. Xylitol and isothiazolones exhibited enhanced synergistic inhibition of initial biofilm formation, and also the structure and production of extracellular polymeric substances by P. aeruginosa ATCC 9027 and S. aureus ATCC 6538 in a dose-dependent manner. In addition, xylitol and isothiazolones inhibited and restored the swimming motility of P. aeruginosa ATCC 9027, respectively. These findings show that a combination of xylitol and isothiazolones exerts pronounced antimicrobial activity against P. aeruginosa and S. aureus biofilms and may be applicable for preventing or reducing bacterial biofilms in vitro.}, } @article {pmid31217292, year = {2019}, author = {Arnaouteli, S and Matoz-Fernandez, DA and Porter, M and Kalamara, M and Abbott, J and MacPhee, CE and Davidson, FA and Stanley-Wall, NR}, title = {Pulcherrimin formation controls growth arrest of the Bacillus subtilis biofilm.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {27}, pages = {13553-13562}, pmid = {31217292}, issn = {1091-6490}, support = {097945/B/11/Z/WT_/Wellcome Trust/United Kingdom ; //Wellcome Trust/United Kingdom ; BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M010996/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; MR/K015869/1/MRC_/Medical Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/*growth & development/metabolism ; Biofilms/*growth & development ; Iron/metabolism ; Iron Deficiencies ; Models, Theoretical ; Pyrazines/*metabolism ; }, abstract = {Biofilm formation by Bacillus subtilis is a communal process that culminates in the formation of architecturally complex multicellular communities. Here we reveal that the transition of the biofilm into a nonexpanding phase constitutes a distinct step in the process of biofilm development. Using genetic analysis we show that B. subtilis strains lacking the ability to synthesize pulcherriminic acid form biofilms that sustain the expansion phase, thereby linking pulcherriminic acid to growth arrest. However, production of pulcherriminic acid is not sufficient to block expansion of the biofilm. It needs to be secreted into the extracellular environment where it chelates Fe[3+] from the growth medium in a nonenzymatic reaction. Utilizing mathematical modeling and a series of experimental methodologies we show that when the level of freely available iron in the environment drops below a critical threshold, expansion of the biofilm stops. Bioinformatics analysis allows us to identify the genes required for pulcherriminic acid synthesis in other Firmicutes but the patchwork presence both within and across closely related species suggests loss of these genes through multiple independent recombination events. The seemingly counterintuitive self-restriction of growth led us to explore if there were any benefits associated with pulcherriminic acid production. We identified that pulcherriminic acid producers can prevent invasion by neighboring communities through the generation of an "iron-free" zone, thereby addressing the paradox of pulcherriminic acid production by B. subtilis.}, } @article {pmid31216375, year = {2019}, author = {Palmioli, A and Sperandeo, P and Polissi, A and Airoldi, C}, title = {Targeting Bacterial Biofilm: A New LecA Multivalent Ligand with Inhibitory Activity.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {20}, number = {23}, pages = {2911-2915}, doi = {10.1002/cbic.201900383}, pmid = {31216375}, issn = {1439-7633}, support = {project n° 2015-0763//Fondazione Cariplo/International ; (FABBR)-MIUR 2018//Ministero dell'Istruzione, dell'Università e della Ricerca/International ; }, mesh = {Adhesins, Bacterial/*metabolism ; Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects ; Dendrimers/chemical synthesis/*pharmacology ; Galactosides/chemical synthesis/*pharmacology ; Ligands ; Pseudomonas aeruginosa/chemistry/drug effects/physiology ; }, abstract = {Biofilm formation by bacterial pathogens is a hallmark of chronic infections and is associated to increased antibiotic tolerance that makes pathogens difficult to eradicate with conventional antibiotic therapies. Infections caused by Pseudomonas aeruginosa are of great concern, especially for immunocompromised and cystic fibrosis patients. P. aeruginosa lectins LecA and LecB are virulence factors and play a key role in establishing biofilm; therefore, inhibition of the function of these proteins has potential in dismantling the bacterium from the protective biofilm environment and in restoring the activity of antibiotics. Here, we report the NMR characterization of the binding of a galactose-based dendrimer (Gal18) to LecA. Moreover, we demonstrate the activity of the Gal18 molecule in inhibiting P. aeruginosa biofilm formation in vitro.}, } @article {pmid31216354, year = {2019}, author = {Pickering, AC and Vitry, P and Prystopiuk, V and Garcia, B and Höök, M and Schoenebeck, J and Geoghegan, JA and Dufrêne, YF and Fitzgerald, JR}, title = {Host-specialized fibrinogen-binding by a bacterial surface protein promotes biofilm formation and innate immune evasion.}, journal = {PLoS pathogens}, volume = {15}, number = {6}, pages = {e1007816}, pmid = {31216354}, issn = {1553-7374}, support = {BB/I013873/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/P013740/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BBS/E/D/20211553/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Bacterial Proteins/genetics/*immunology ; Biofilms/*growth & development ; Chickens ; Dogs ; Fibrinogen/genetics/*immunology ; Humans ; *Immune Evasion ; *Immunity, Innate ; Staphylococcus/*physiology ; }, abstract = {Fibrinogen is an essential part of the blood coagulation cascade and a major component of the extracellular matrix in mammals. The interface between fibrinogen and bacterial pathogens is an important determinant of the outcome of infection. Here, we demonstrate that a canine host-restricted skin pathogen, Staphylococcus pseudintermedius, produces a cell wall-associated protein (SpsL) that has evolved the capacity for high strength binding to canine fibrinogen, with reduced binding to fibrinogen of other mammalian species including humans. Binding occurs via the surface-expressed N2N3 subdomains, of the SpsL A-domain, to multiple sites in the fibrinogen α-chain C-domain by a mechanism analogous to the classical dock, lock, and latch binding model. Host-specific binding is dependent on a tandem repeat region of the fibrinogen α-chain, a region highly divergent between mammals. Of note, we discovered that the tandem repeat region is also polymorphic in different canine breeds suggesting a potential influence on canine host susceptibility to S. pseudintermedius infection. Importantly, the strong host-specific fibrinogen-binding interaction of SpsL to canine fibrinogen is essential for bacterial aggregation and biofilm formation, and promotes resistance to neutrophil phagocytosis, suggesting a key role for the interaction during pathogenesis. Taken together, we have dissected a bacterial surface protein-ligand interaction resulting from the co-evolution of host and pathogen that promotes host-specific innate immune evasion and may contribute to its host-restricted ecology.}, } @article {pmid31214138, year = {2019}, author = {Flament-Simon, SC and Duprilot, M and Mayer, N and García, V and Alonso, MP and Blanco, J and Nicolas-Chanoine, MH}, title = {Association Between Kinetics of Early Biofilm Formation and Clonal Lineage in Escherichia coli.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {1183}, pmid = {31214138}, issn = {1664-302X}, abstract = {BACKGROUND: Escherichia coli biofilm formation has mostly been assessed in specific pathogenic E. coli groups. Here, we assessed the early biofilm formation (EBF), i.e., adhesion stage, using the BioFilm Ring Test[®] on 394 E. coli clinical isolates (EC) [196 consecutively isolated (CEC) in 2016 and 198 ESBL-producing E. coli (ESBLEC) isolated in 2015]. Then, biofilm-forming ability was contrasted with phylogroups, clonotypes (fumC-fimH), and sequence types (STs), all being used to define clones, virulence factors (VF), and FimB.

RESULT: According to both biofilm production levels at 2, 3, and 5 h, and EBF kinetics over 5 h, CEC and ESBLEC isolates segregated into three EBF groups: strong (G1), moderate (G2), and weak (G3) producers. At 2 h, strong producers were more frequent among CEC (n = 28; 14.3%) than among ESBLEC (n = 8; 4%) (P = 0.0004). As CEC and ESBLEC isolates showed similar individual EBF kinetics in each group, a comparison of isolate features between each group was applied to gathered CEC and ESBLEC isolates after 2 h of incubation, 2 h being the most representative time point of the CEC and ESBLEC isolate segregation into the three groups. Phylogroup B2 displayed by 51.3% of the 394 isolates was more frequent in G1 (77.8%) than in G3 (47.6%) (P = 0.0006). The 394 isolates displayed 153 clones, of which 31 included at least three isolates. B2-CH14-2-ST127, B2-CH40-22-ST131, B2-CH52-5/14-ST141, and E-CH100-96-ST362 clones were associated with G1 (P < 0.03) and accounted for 41.7% of G1 isolates. B2-CH40-30-ST131 clone was associated with G3 (P < 0.0001) and accounted for 25.5% of G3 isolates. VF mean was higher among G1 than among G3 isolates (P < 0.001). FimB-P2 variant was associated with G1 (P = 0.0011) and FimB-P1 variant was associated with G3 (P = 0.0023). Clone, some VF, and FimB were associated with EBF, with clonal lineage being able to explain 72% of the variability of EBF.

CONCLUSION: Among our 394 isolates, <10% are able to quickly and persistently produce high biofilm levels over 5 h. These isolates belong to a few clones previously described in various studies as dominant gut colonizers in mammalians and birds and comprised the B2-CH40-22-ST131 clone, i.e., the ancestor of the globally disseminated B2-CH40-30-ST131 clone that is the dominant clone among the weak biofilm producers.}, } @article {pmid31213555, year = {2019}, author = {Keogh, D and Lam, LN and Doyle, LE and Matysik, A and Pavagadhi, S and Umashankar, S and Low, PM and Dale, JL and Song, Y and Ng, SP and Boothroyd, CB and Dunny, GM and Swarup, S and Williams, RBH and Marsili, E and Kline, KA}, title = {Correction for Keogh et al., "Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism".}, journal = {mBio}, volume = {10}, number = {3}, pages = {}, doi = {10.1128/mBio.01080-19}, pmid = {31213555}, issn = {2150-7511}, } @article {pmid31212792, year = {2019}, author = {Cepas, V and López, Y and Gabasa, Y and Martins, CB and Ferreira, JD and Correia, MJ and Santos, LMA and Oliveira, F and Ramos, V and Reis, M and Castelo-Branco, R and Morais, J and Vasconcelos, V and Probert, I and Guilloud, E and Mehiri, M and Soto, SM}, title = {Inhibition of Bacterial and Fungal Biofilm Formation by 675 Extracts from Microalgae and Cyanobacteria.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {31212792}, issn = {2079-6382}, support = {634588//Horizon 2020 Framework Programme/ ; }, abstract = {Bacterial biofilms are complex biological systems that are difficult to eradicate at a medical, industrial, or environmental level. Biofilms confer bacteria protection against external factors and antimicrobial treatments. Taking into account that about 80% of human infections are caused by bacterial biofilms, the eradication of these structures is a great priority. Biofilms are resistant to old-generation antibiotics, which has led to the search for new antimicrobials from different sources, including deep oceans/seas. In this study, 675 extracts obtained from 225 cyanobacteria and microalgae species (11 phyla and 6 samples belonging to unknown group) were obtained from different culture collections: The Blue Biotechnology and Ecotoxicology Culture Collection (LEGE-CC), the Coimbra Collection of Algae (ACOI) from Portugal, and the Roscoff Culture Collection (RCC) from France. The largest number of samples was made up of the microalgae phylum Chlorophyta (270) followed by Cyanobacteria (261). To obtain a large range of new bioactive compounds, a method involving three consecutive extractions (hexane, ethyl acetate, and methanol) was used. The antibiofilm activity of extracts was determined against seven different bacterial species and two Candida strains in terms of minimal biofilm inhibitory concentration (MBIC). The highest biofilm inhibition rates (%) were achieved against Candida albicans and Enterobacter cloacae. Charophyta, Chlorophyta, and Cyanobacteria were the most effective against all microorganisms. In particular, extracts of Cercozoa phylum presented the lowest MBIC50 and MBIC90 values for all the strains except C. albicans.}, } @article {pmid31211205, year = {2019}, author = {Heuschkel, I and Hoschek, A and Schmid, A and Bühler, B and Karande, R and Bühler, K}, title = {Data on mixed trophies biofilm for continuous cyclohexane oxidation to cyclohexanol using Synechocystis sp. PCC 6803.}, journal = {Data in brief}, volume = {25}, number = {}, pages = {104059}, pmid = {31211205}, issn = {2352-3409}, abstract = {Photosynthetic microorganisms offer promising perspectives for the sustainable production of value-added compounds. Nevertheless, the cultivation of phototrophic organisms to high cell densities (HCDs) is hampered by limited reactor concepts. Co-cultivation of the photoautotrophic Synechocystis sp. PCC 6803 and the chemoheterotrophic P. taiwanensis VLB 120 enabled HCDs up to 51.8 gCDW L[-1]. Respective biofilms have been grown as a biofilm in capillary flow-reactors, and oxygen evolution, total biomass, as well as the ratio of the two strains, have been followed under various cultivation conditions. Furthermore, biofilm formation on a microscopic level was analyzed via confocal laser scanning microscopy using a custom made flow-cell setup. The concept of mixed trophies co-cultivation was coupled to biotransformation, namely the oxyfunctionalization of cyclohexane to cyclohexanol. For benchmarking, the performance of the phototrophic reaction was compared to the chemical process, and to a biotechnological approach using a heterotrophic organism only. The data presented refer to our research paper "Mixed-species biofilms for high-cell-density application of Synechocystis sp. PCC 6803 in capillary reactors for continuous cyclohexane oxidation to cyclohexanol" Hoschek et al., 2019.}, } @article {pmid31209011, year = {2019}, author = {Rodríguez López, AL and Lee, MR and Wang, NB and Dunn, KK and Sanchez, H and Raman, N and Andes, DR and Lynn, DM and Palecek, SP}, title = {Small-Molecule Morphogenesis Modulators Enhance the Ability of 14-Helical β-Peptides To Prevent Candida albicans Biofilm Formation.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {9}, pages = {}, pmid = {31209011}, issn = {1098-6596}, support = {P41 RR002301/RR/NCRR NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; R21 AI127442/AI/NIAID NIH HHS/United States ; R01 AI092225/AI/NIAID NIH HHS/United States ; R33 AI127442/AI/NIAID NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/growth & development ; Hyphae/drug effects/growth & development ; Pentanols ; Peptides/chemistry/*pharmacology ; }, abstract = {Candida albicans is an opportunistic fungal pathogen responsible for mucosal candidiasis and systemic candidemia in humans. Often, these infections are associated with the formation of drug-resistant biofilms on the surfaces of tissues or medical devices. Increased incidence of C. albicans resistance to current antifungals has heightened the need for new strategies to prevent or eliminate biofilm-related fungal infections. In prior studies, we designed 14-helical β-peptides to mimic the structural properties of natural antimicrobial α-peptides (AMPs) in an effort to develop active and selective antifungal compounds. These amphiphilic, cationic, helical β-peptides exhibited antifungal activity against planktonic C. albicans cells and inhibited biofilm formation in vitro and in vivo Recent studies have suggested the use of antivirulence agents in combination with antifungals. In this study, we investigated the use of compounds that target C. albicans polymorphism, such as 1-dodecanol, isoamyl alcohol, and farnesol, to attempt to improve β-peptide efficacy for preventing C. albicans biofilms. Isoamyl alcohol, which prevents hyphal formation, reduced the minimum biofilm prevention concentrations (MBPCs) of β-peptides by up to 128-fold. Combinations of isoamyl alcohol and antifungal β-peptides resulted in less than 10% hemolysis at the antifungal MBPCs. Overall, our results suggest potential benefits of combination therapies comprised of morphogenesis modulators and antifungal AMP peptidomimetics for preventing C. albicans biofilm formation.}, } @article {pmid31207891, year = {2019}, author = {Fu, TK and Ng, SK and Chen, YE and Lee, YC and Demeter, F and Herczeg, M and Borbás, A and Chiu, CH and Lan, CY and Chen, CL and Chang, MD}, title = {Rhamnose Binding Protein as an Anti-Bacterial Agent-Targeting Biofilm of Pseudomonas aeruginosa.}, journal = {Marine drugs}, volume = {17}, number = {6}, pages = {}, pmid = {31207891}, issn = {1660-3397}, support = {MOST 103-2627-M-007-006//Ministry of Science and Technology/ ; MOST 107-0210-01-19-04//Ministry of Science and Technology/ ; GINOP-2.3.2-15-2016-00008//European Regional Development Fund/ ; ÚNKP-18-3 New National Excellence Program//Ministry of Human Capacities of Hungary/ ; }, mesh = {A549 Cells ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Carrier Proteins/*metabolism ; Cell Line, Tumor ; Epithelial Cells/drug effects ; Escherichia coli/metabolism ; Glycolipids/metabolism ; Horseshoe Crabs/metabolism ; Humans ; Lectins/metabolism ; Polysaccharides, Bacterial/metabolism ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/drug effects ; Rhamnose/*metabolism ; Zebrafish ; }, abstract = {More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.}, } @article {pmid31207076, year = {2019}, author = {Liang, D and Li, H and Xu, X and Liang, J and Dai, X and Zhao, W}, title = {Rational design of peptides with enhanced antimicrobial and anti-biofilm activities against cariogenic bacterium Streptococcus mutans.}, journal = {Chemical biology & drug design}, volume = {94}, number = {4}, pages = {1768-1781}, doi = {10.1111/cbdd.13579}, pmid = {31207076}, issn = {1747-0285}, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Dental Caries/*drug therapy ; Humans ; *Peptides/chemical synthesis/chemistry/pharmacology ; Streptococcus mutans/*physiology ; }, abstract = {Streptococcus mutans (S. mutans) is known to be a leading cariogenic pathogen in the oral cavity. Antimicrobial peptides possess excellent properties to combat such pathogens. In this study, we compared the antimicrobial activity of novel linear reutericin 6- and/or gassericin A-inspired peptides and identified LR-10 as the leading peptide. Antibacterial assays demonstrate that LR-10 is more active against S. mutans (3.3 μM) than many peptide-based agents without resistance selection, capable of killing many oral pathogens, and tolerant of physiological conditions. LR-10 also presented a faster killing rate than chlorhexidine and erythromycin, and appeared to display selective activity against S. mutans within 10 s. S. mutans is usually encased in plaque biofilms. Biofilm inhibitory assays indicated that LR-10 had excellent inhibitory effect on the biofilm formation of S. mutans and biofilm-encased cells in vitro at low concentrations (6.5 μM). Consistent with most peptides, LR-10 kills S. mutans mainly by disrupting the cell membranes. Notably, both hemolytic activity assays and cytotoxicity tests indicated that LR-10 could keep biocompatible at the effective concentrations. Hence, LR-10 could be a good candidate for clinical treatment of dental caries.}, } @article {pmid31206966, year = {2019}, author = {Melian, C and Segli, F and Gonzalez, R and Vignolo, G and Castellano, P}, title = {Lactocin AL705 as quorum sensing inhibitor to control Listeria monocytogenes biofilm formation.}, journal = {Journal of applied microbiology}, volume = {127}, number = {3}, pages = {911-920}, doi = {10.1111/jam.14348}, pmid = {31206966}, issn = {1365-2672}, support = {PICT2016, PICT2014//Agencia Nacional de Promoción Científica y Tecnológica/ ; 0585//Agencia Nacional de Promoción Científica y Tecnológica/ ; 441//Consejo Nacional de Investigaciones Científicas y Técnicas/ ; }, mesh = {Bacteriocins/*pharmacology ; Biofilms/*drug effects ; Food Contamination ; Listeria/drug effects ; Listeria monocytogenes/*drug effects/physiology ; Microbial Sensitivity Tests ; Quorum Sensing/*drug effects ; }, abstract = {AIMS: The control of Listeria monocytogenes biofilm formation using lactocin AL705 bacteriocin at sub-minimum inhibitory concentrations (MICs) through an antiquorum sensing strategy, was preliminarily investigated.

METHODS AND RESULTS: The screening for biofilm formation of different Listeria species at 10°C allowed selecting L. monocytogenes FBUNT for its use as biofilm producer. MIC and minimum bactericidal concentration of lactocin AL705 purified extract against the pathogen was determined. Bacteriocin sub-MICs were used to evaluate biofilm reduction. Concentrations between 2·5-20 AU ml[-1] of lactocin AL705 produced significant decreases in biofilm formation without affecting the growth of the pathogen after 3 days of incubation. When bacteriocin concentrations (5-20 arbitrary units per millilitre (AU ml[-1])) were investigated as quorum sensing (QS) inhibitors using Vibrio harveyi as reporter strain, a significant reduction in luminescence by lactocin AL705 (20 AU ml[-1]) was observed. Even when L. monocytogenes produced AI-2 like molecules as recognized by the reporter strain, bacteriocins did not interfere with this compound.

CONCLUSION: Antilisterial lactocin AL705 used to disrupt QS through a signal molecule inactivation was able to control L. monocytogenes FBUNT biofilm formation. Other molecule(s) different from the AI-2 involved during biofilm formation could be acting as target of the bacteriocin.

The use of bacteriocins derived from food-grade micro-organisms as a QS inhibition represents an effective strategy to control pathogens as well as an environmentally friendly sanitation method to mitigate postprocessing food contamination.}, } @article {pmid31202712, year = {2019}, author = {Zhao, Y and Liu, D and Huang, W and Yang, Y and Ji, M and Nghiem, LD and Trinh, QT and Tran, NH}, title = {Insights into biofilm carriers for biological wastewater treatment processes: Current state-of-the-art, challenges, and opportunities.}, journal = {Bioresource technology}, volume = {288}, number = {}, pages = {121619}, doi = {10.1016/j.biortech.2019.121619}, pmid = {31202712}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Biofilm carriers play an important role in attached growth systems for wastewater treatment processes. This study systematically summarizes the traditional and novel biofilm carriers utilized in biofilm-based wastewater treatment technology. The advantages and disadvantages of traditional biofilm carriers are evaluated and discussed in light of basic property, biocompatibility and applicability. The characteristics, applications performance, and mechanism of novel carriers (including slow-release carriers, hydrophilic/electrophilic modified carriers, magnetic carriers and redox mediator carriers) in wastewater biological treatment were deeply analyzed. Slow release biofilm carriers are used to provide a solid substrate and electron donor for the growth of microorganisms and denitrification for anoxic and/or anaerobic bioreactors. Carriers with hydrophilic/electrophilic modified surface are applied for promoting biofilm formation. Magnetic materials-based carriers are employed to shorten the start-up time of bioreactor. Biofilm carriers acting as redox mediators are used to accelerate biotransformation of recalcitrant pollutants in industrial wastewater.}, } @article {pmid31202424, year = {2019}, author = {Moraes, JO and Cruz, EA and Pinheiro, Í and Oliveira, TCM and Alvarenga, V and Sant'Ana, AS and Magnani, M}, title = {An ordinal logistic regression approach to predict the variability on biofilm formation stages by five Salmonella enterica strains on polypropylene and glass surfaces as affected by pH, temperature and NaCl.}, journal = {Food microbiology}, volume = {83}, number = {}, pages = {95-103}, doi = {10.1016/j.fm.2019.04.012}, pmid = {31202424}, issn = {1095-9998}, mesh = {Bacterial Adhesion ; *Biofilms ; Colony Count, Microbial ; *Glass ; Hydrogen-Ion Concentration ; Logistic Models ; *Polypropylenes ; Regression Analysis ; Salmonella enterica/drug effects/*physiology ; Sodium Chloride/*pharmacology ; *Temperature ; }, abstract = {This study assessed the adhesion and formation of biofilm by five Salmonella enterica strains (S. Enteritidis 132, S. Infantis 176, S. Typhimurium 177, S. Heidelberg 281 and S. Corvallis 297) on polypropylene (PP) and glass (G) surfaces as affected by pH (4-7), NaCl concentration (0-10% w/v) and temperature (8-35 °C). Sessile counts <3 log CFU/cm[2] were considered lack of adhesion (category 1), while counts ≥ 3 and < 5 log CFU/cm[2] corresponded to adhesion (category 2) and counts ≥ 5 log CFU/cm[2] corresponded biofilm formation (category 3). The obtained results categorized in these three responses were used to develop ordinal regression models to predict the probability of biofilm stages on PP- and G-surfaces. The experimental outcomes for lack of adhesion were >90% on PP- and G-surfaces. Generally, adhesion outcomes corresponded to approximately 36% of the total, whereas biofilm outcomes were close to 65% in both PP- and G-surfaces. The biofilm stages varied among the strains studied and with the material surface under the same experimental conditions. According to the generated ordinal models, the probability of adhesion and biofilm formation on PP-surface by the five S. enterica strains tested decreased at pH 4 or 5 in NaCl concentrations >4% and at a temperature <20 °C. On G-surface, the probability of adhesion increased pH 6 or 7, in the absence of NaCl and temperatures <20 °C, while, the probability of biofilm formation increased in the same pH, NaCl concentration up to 4% and temperatures ≥20 °C. This is the first study assessing the biofilm formation through categorical, ordinal responses and it shows that ordinal regression models can be useful to predict biofilm stages of S. enterica as a function of pH, NaCl, and temperature or their interactions.}, } @article {pmid31202413, year = {2019}, author = {García-Sánchez, L and Melero, B and Jaime, I and Rossi, M and Ortega, I and Rovira, J}, title = {Biofilm formation, virulence and antimicrobial resistance of different Campylobacter jejuni isolates from a poultry slaughterhouse.}, journal = {Food microbiology}, volume = {83}, number = {}, pages = {193-199}, doi = {10.1016/j.fm.2019.05.016}, pmid = {31202413}, issn = {1095-9998}, mesh = {*Abattoirs ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Typing Techniques ; Biofilms/*growth & development ; Campylobacter Infections/*veterinary ; Campylobacter jejuni/*drug effects/genetics/*pathogenicity ; Ciprofloxacin/pharmacology ; Drug Resistance, Bacterial/genetics ; Food Microbiology ; Genome, Bacterial ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Poultry/*microbiology ; Virulence Factors/genetics ; Whole Genome Sequencing ; }, abstract = {The fastidious requirement of the zoonotic pathogen Campylobacter jejuni contrasts with its ability to overcome harsh conditions. Different strategies might be involved in the survival and persistence of C. jejuni through the poultry food chain. Therefore, the aims of this study were to get insights in the survival strategies in the poultry slaughterhouse environment by (i) characterizing factors such as biofilm formation, virulence and antimicrobial resistance in environmental isolates and (ii) understanding the possible link between the phenotypic and genetic characterization using whole genome sequencing (WGS). Results have shown that three STs: ST 443 (PFGE A), ST 904 (PFGE C) and ST 3769 (PFGE G), out of the six studied, formed biofilms with variable intensity according to different conditions (temperatures -37 °C, 30 °C, 25°C- and materials -stainless steel and plastic-). High levels of antimicrobial resistance were found in isolates to ciprofloxacin, nalidixic acid and tetracycline as well as to two common detergents used in the slaughterhouse. A combination of several changes in the genome of ST 904 (PFGE C) including mutations, insertions in antimicrobial resistance genes, the presence of T6SS and a set of genes related to virulence factors might explain its ability to form biofilm and persist longer in the environment. However, the complexity of the survival strategies adopted by the different strains of C. jejuni suggests that multiple mechanisms may exist that allow these organisms to persist and ultimately cause disease in humans.}, } @article {pmid31200347, year = {2019}, author = {Dawas, A and Abu-Salih, S and Sabbah, I and Nejidat, A and Dosoretz, CG}, title = {Controlling nitritation in a continuous split-feed/aeration biofilm nitrifying bioreactor.}, journal = {Bioresource technology}, volume = {288}, number = {}, pages = {121599}, doi = {10.1016/j.biortech.2019.121599}, pmid = {31200347}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Archaea ; Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; }, abstract = {This study explored the stability of partial ammonium oxidation at low feed concentration (50 g N/m[3]), suitable for anammox process, in continuous fixed bed up-flow biofilm reactors with external recirculation-aeration. The reactors, filled with crushed basalt, were fed with synthetic medium at 20-25 °C at constant flow-rate with limiting dissolved oxygen concentration controlled by the recirculation ratio (R). Successful nitritation was achieved at R ≅ 4-6 with approx. 50% of NH4[+] oxidized to NO2[-] with <5% NO3[-]accumulation. q-PCR analysis along the reactor showed ammonia oxidizing bacteria being the prevalent nitrifiers over the three-fourths of the bed in the flow direction, negligible denitrifiers and absent ammonium oxidizing archaea. A numerical model for predicting the concentration of the nitrogen species and DO was formulated. The model successfully predicted the experimental results and displayed good sensitivity to intrinsic oxygen uptake parameters. The proposed numerical model can serve both as an operational and design tool.}, } @article {pmid31198058, year = {2019}, author = {Manilal, A and Shewangizaw, M and Mama, M and Gezmu, T and Merdekios, B}, title = {Methicillin-resistant Staphylococcus aureus colonization in HIV patients of Arba Minch province, Ethiopia: Carriage rates, antibiotic resistance, and biofilm formation.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {66}, number = {4}, pages = {469-483}, doi = {10.1556/030.66.2019.014}, pmid = {31198058}, issn = {1588-2640}, mesh = {Adolescent ; Adult ; Aged ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Carrier State/*epidemiology/microbiology ; Cross-Sectional Studies ; Drug Resistance, Microbial ; Drug Resistance, Multiple, Bacterial ; Ethiopia/epidemiology ; Female ; HIV Infections/*microbiology ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Middle Aged ; Nose/microbiology ; Prevalence ; Staphylococcal Infections/epidemiology ; Young Adult ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a significant opportunistic pathogen among human immunodeficiency virus (HIV) patients of Ethiopia. This study aimed at delineating the prevalence, antimicrobial resistance, and biofilm-forming potentials of nasally colonized MRSA among HIV patients in the Arba Minch province of Ethiopia. A cross-sectional study was performed in HIV patients who visit anti-retroviral therapy clinic of the Arba Minch Hospital between February and April 2017. Nasal samples were collected and inspected for Staphylococcus following standard procedures. MRSA was identified using cefoxitin disk and antibiotics sensitivity test was performed as per Kirby-Baur disk diffusion method. The formation of biofilm was inspected using both qualitative and quantitative methods. A total of 307 HIV patients were examined. The overall prevalence of S. aureus was found to be 39.7%. The prevalence of MRSA was 20.8%. The rate of nasal colonization of MRSA was relatively higher among females. In bivariate analysis, MRSA colonization was statistically significant in patients with CD4 count ≤350 (p value = 0.002) and co-trimoxazole prophylaxis (p value = 0.003). Concomitant resistance to erythromycin, tetracycline, and co-trimoxazole were 48.4%, 45.3%, and 39.0%, respectively. Invariably, all MRSA isolates were 100% sensitive to vancomycin. Of the 64 MRSA isolates, 18.7% were considered as multidrug-resistant. The rate of biofilm formation was 34.3%. The results revealed a high prevalence rate in the nasal colonization of MRSA in HIV patients.}, } @article {pmid31198057, year = {2019}, author = {Shivaee, A and Mohammadzadeh, R and Shahbazi, S and Pardakhtchi, E and Ohadi, E and Kalani, BS}, title = {Time-variable expression levels of mazF, atlE, sdrH, and bap genes during biofilm formation in Staphylococcus epidermidis.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {66}, number = {4}, pages = {499-508}, doi = {10.1556/030.66.2019.019}, pmid = {31198057}, issn = {1588-2640}, mesh = {Bacterial Adhesion ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Staphylococcus epidermidis/*genetics/physiology ; Time Factors ; }, abstract = {Staphylococcus epidermidis is an opportunistic pathogen causing infections related to the usage of implants and medical devices. Pathogenicity of this microorganism is mainly linked to its capability to form biofilm structures. Biofilm formation vastly depends on several factors including different proteins. We studied the expression levels of three proteins including SdrH, Bap, AtlE, and MazF at different time intervals during the course of biofilm formation. In this study, a catheter-derived S. epidermidis isolate with strong ability of biofilm formation was selected. PCR assay was used to detect sdrH, bap, atlE, and mazF genes in this isolate. Real-time PCR was used to determine the expression levels of these genes after 4, 8, and 20 h during the course of biofilm formation. The studied genes showed different expression levels at different time intervals during biofilm formation by real-time PCR method. Expression levels of atlE and sdrH genes were the highest at 4 h, whereas bap gene showed the highest expression level at 8 h during the course of biofilm formation. In addition, the expression level of mazF gene peaked at 4 h and then progressively decreased at 8 and 20 h. Our results suggest the importance of AtlE, SdrH, and MazF proteins in the establishment and development of the biofilm structure. In addition, our results showed the important role of protein Bap in the accumulation of biofilm structure. Future studies are required to understand the exact role of MazF in the process of biofilm formation.}, } @article {pmid31197408, year = {2019}, author = {Ariafar, MN and Iğci, N and Akçelik, M and Akçelik, N}, title = {Investigation of the effect of different environmental conditions on biofilm structure of Salmonella enterica serotype Virchow via FTIR spectroscopy.}, journal = {Archives of microbiology}, volume = {201}, number = {9}, pages = {1233-1248}, doi = {10.1007/s00203-019-01681-5}, pmid = {31197408}, issn = {1432-072X}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Carbohydrates ; Cellulose/metabolism ; Fimbriae, Bacterial/metabolism ; Membrane Lipids/metabolism ; Nucleic Acids/metabolism ; Salmonella enterica/*growth & development/*metabolism ; Serogroup ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {This study aims to describe the content of polymeric matrix components under different incubation temperatures and pH levels. Optimal biofilm production of 15 S. Virchow isolates occurred following the incubation in LB[-NaCl] for 72 h, at pH 6.6 and 20 °C. The expression of csgA, csgD, adrA and bcsA genes at 20 °C, 25 °C and 30 °C in S. Virchow DMC18 was analyzed, and it was discovered that the maximum production of cellulose and curli fimbriae occurred at 20 °C. The physical characteristics of pellicle structure of S. Virchow DMC18 was determined as rigid at 20 °C, while becoming fragile at higher temperatures. FTIR analyses confirmed the obtained molecular findings. The intensities of the 16 different peaks originating from carbohydrate, protein, and nucleic acid in the spectra of biofilm samples significantly diminished (p < 0.05) with the increasing temperature. The highest intensities of lipids and carbohydrates were observed at 20 °C indicating the changes in cell surface properties.}, } @article {pmid31195653, year = {2019}, author = {Zhou, Y and Gao, X}, title = {Characterization of Biofilm Formed by Phenanthrene-Degrading Bacteria on Rice Root Surfaces for Reduction of PAH Contamination in Rice.}, journal = {International journal of environmental research and public health}, volume = {16}, number = {11}, pages = {}, pmid = {31195653}, issn = {1660-4601}, mesh = {Biodegradation, Environmental ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/metabolism ; Oryza/metabolism/*microbiology ; Phenanthrenes/*metabolism ; Plant Roots/metabolism/*microbiology ; Pseudomonas/*physiology ; Soil Pollutants/*metabolism ; }, abstract = {One effective method in to reduce the uptake of organic contaminants by plants is the development of a root barrier. In this study, the characterization of biofilm structure and function by phenanthrene-degrading Pseudomonas sp. JM2-gfp on rice root surfaces were carried out. Our results showed that root surfaces from three rice species, namely Liaojing401, Koshihikari, and Zhenzhuhong all present hydrophobicity and a high initial adhesion of strain JM2-gfp. Matured robust biofilm formation occurred at 48 h on the root surfaces. The biofilm exhibited cell dense aggregates and biomass embedded in the extracellular polymeric substance (EPS) matrix. EPS composition results showed that the proteins, carbohydrates, lipids and nucleic acids are produced in the biofilm, while the content varied with rice species. Under the initial concentration of phenanthrene 50 mg·L[-1], the residual phenanthrene in plant roots from 'Zhengzhuhong', 'Koshihikari' and 'Liaojing401' with biofilm mediated were significantly decreased by 71.9%, 69.3% and 58.7%, respectively, compared to those without biofilm groups after 10 days of exposure. Thus, the biofilm colonized on roots plays an important role of degradation in order to reduce the level of phenanthrene uptake of plants. Thereby, the present work provides significant new insights into lowering the environmental risks of polycyclic aromatic hydrocarbons (PAHs) in crop products from contaminated agriculture soils.}, } @article {pmid31195361, year = {2019}, author = {Zheng, M and Zhu, H and Han, Y and Xu, C and Zhang, Z and Han, H}, title = {Comparative investigation on carbon-based moving bed biofilm reactor (MBBR) for synchronous removal of phenols and ammonia in treating coal pyrolysis wastewater at pilot-scale.}, journal = {Bioresource technology}, volume = {288}, number = {}, pages = {121590}, doi = {10.1016/j.biortech.2019.121590}, pmid = {31195361}, issn = {1873-2976}, mesh = {*Ammonia ; Biofilms ; Bioreactors ; Carbon ; Coal ; Phenols ; Pyrolysis ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {By regulating the extraction solvent and alkali in pretreatment, two carbon-based MBBRs were compared in pilot-scale to synchronously remove phenols and ammonia of coal pyrolysis wastewater (CPW) under fluctuant phenols-ammonia loadings. It revealed that lignite activated coke (LAC)-based MBBR performed more stable with phenols increasing (250-550 mg/L), and reached higher tolerance limit to ammonia (>320 mg/L) than activated carbon (AC)-based MBBR under fluctuant ammonia loadings. During the phenols-ammonia synchronous removal process, the LAC provided the firm basis for shock resistance due to superior resilient adsorption capacity, enhanced sludge property and microbial cooperation. Furthermore, microbial analysis revealed that the strengthened collaboration between archaea and facultative bacteria played the primary role in phenols-ammonia synchronous degradation. Specifically, the heterotrophic bacteria consumed phenols-ammonia by partial nitrification process and ammonia assimilation, following by denitrifying process to further eliminate phenols. The multifunctional Comamonas was the critical genus participating in all procedures.}, } @article {pmid31194941, year = {2019}, author = {Zeng, R and Xu, H and Liu, Y and Du, L and Duan, Z and Tong, J and He, Y and Chen, Q and Chen, X and Li, M}, title = {miR-146a Inhibits Biofilm-Derived Cutibacterium acnes-Induced Inflammatory Reactions in Human Keratinocytes.}, journal = {The Journal of investigative dermatology}, volume = {139}, number = {12}, pages = {2488-2496.e4}, doi = {10.1016/j.jid.2019.03.1161}, pmid = {31194941}, issn = {1523-1747}, mesh = {Biofilms/*drug effects ; Cells, Cultured ; Cytokines/metabolism ; *Gene Expression Regulation ; Gram-Positive Bacterial Infections/*genetics/metabolism/pathology ; Humans ; Keratinocytes/*microbiology/pathology ; MicroRNAs/*genetics ; Propionibacterium acnes/*physiology ; RNA/genetics ; Signal Transduction ; }, abstract = {Acne is a chronic inflammatory skin disorder that often involves the formation of Cutibacterium acnes (C. acnes) biofilms. Several microRNAs (miRNAs) are known to be involved in inflammatory responses. However, it is unknown whether miRNAs play a role in the inflammatory reaction triggered by C. acnes biofilm. In this study, we investigated the role of miR-146a in biofilm-derived C. acnes-induced inflammatory responses. Increased expressions of miR-146a and toll-like receptor (TLR) 2 were detected in acne lesions. In the presence of biofilm-derived C. acnes, TLR2 and its downstream NF-kB and MAPK pathways were activated in keratinocytes. Subsequently, miR-146a was upregulated in these cells along with the induction of IL-6, IL-8, and tumor necrosis factor (TNF)-α. Furthermore, our data indicates that miR-146a could directly bind the 3'-untranslated region of IRAK1 and TNF receptor-associated factor 6 (TRAF6) and suppress their expression, leading to an inhibition of biofilm-derived C. acnes-induced activation of NF-kB, p38, and ERK1/2 pathways. Overall, our results indicate that biofilm-derived C. acnes induces miR-146a, which can downregulate the production of IL-6, -8, and TNF-α in acne inflammation by inhibiting the TLR2/IRAK1/TRAF6/NF-κB and MAPK pathways.}, } @article {pmid31194008, year = {2018}, author = {Sanawar, H and Pinel, I and Farhat, NM and Bucs, SS and Zlopasa, J and Kruithof, JC and Witkamp, GJ and van Loosdrecht, MCM and Vrouwenvelder, JS}, title = {Enhanced biofilm solubilization by urea in reverse osmosis membrane systems.}, journal = {Water research X}, volume = {1}, number = {}, pages = {100004}, pmid = {31194008}, issn = {2589-9147}, abstract = {Chemical cleaning is routinely performed in reverse osmosis (RO) plants for the regeneration of RO membranes that suffer from biofouling problems. The potential of urea as a chaotropic agent to enhance the solubilization of biofilm proteins has been reported briefly in the literature. In this paper the efficiency of urea cleaning for RO membrane systems has been compared to conventionally applied acid/alkali treatment. Preliminary assessment confirmed that urea did not damage the RO polyamide membranes and that the membrane cleaning efficiency increased with increasing concentrations of urea and temperature. Accelerated biofilm formation was carried out in membrane fouling simulators which were subsequently cleaned with (i) 0.01M sodium hydroxide (NaOH) and 0.1M hydrochloric acid (HCl) (typically applied in industry), (ii) urea (CO(NH2)2) and hydrochloric acid, or (iii) urea only (1340 g/Lwater). The pressure drop over the flow channel was used to evaluate the efficiency of the applied chemical cleanings. Biomass removal was evaluated by measuring chemical oxygen demand (COD), adenosine triphosphate (ATP), protein, and carbohydrate content from the membrane and spacer surfaces after cleaning. In addition to protein and carbohydrate quantification of the extracellular polymeric substances (EPS), fluorescence excitation-emission matrix (FEEM) spectroscopy was used to distinguish the difference in organic matter of the remaining biomass to assess biofilm solubilization efficacy of the different cleaning agents. Results indicated that two-stage CO(NH2)2/HCl cleaning was as effective as cleaning with NaOH/HCl in terms of restoring the feed channel pressure drop (>70% pressure drop decrease). One-stage cleaning with urea only was not as effective indicating the importance of the second-stage low pH acid cleaning in weakening the biofilm matrix. All three chemical cleaning protocols were equally effective in reducing the concentration of predominant EPS components protein and carbohydrate (>50% reduction in concentrations). However, urea-based cleaning strategies were more effective in solubilizing protein-like matter and tyrosine-containing proteins. Furthermore, ATP measurements showed that biomass inactivation was up to two-fold greater after treatment with urea-based chemical cleanings compared to the conventional acid/alkali treatment. The applicability of urea as an alternative, economical, eco-friendly and effective chemical cleaning agent for the control of biological fouling was successfully demonstrated.}, } @article {pmid31193536, year = {2019}, author = {Gomes, F and Martins, N and Ferreira, ICFR and Henriques, M}, title = {Anti-biofilm activity of hydromethanolic plant extracts against Staphylococcus aureus isolates from bovine mastitis.}, journal = {Heliyon}, volume = {5}, number = {5}, pages = {e01728}, pmid = {31193536}, issn = {2405-8440}, abstract = {Bovine mastitis (BM) presents a high incidence, being Staphylococcus aureus one of the major causative agents. Antibiotics comprise the most common therapeutic approach, but due to their indiscriminate use, high rates of increasingly resistant bacterial species have been markedly pointed out. Particularly, S. aureus possesses a pronounced ability to form biofilms, and therefore, are of pivotal interest due to its alarming pathogenicity. The present study investigates the antibacterial properties of Eucalyptus globulus methanol: water extracts, alone and in combination with Juglans regia, against S. aureus isolates from BM. All isolates and reference strain proved to be good biofilm producers after 24 h of bacterial growth. Individually, the studied plant extracts (PE) lead to a considerable biofilm cells reduction, but their combination revealed to be the most effective strategy. When tested in combination, both extracts led to a 3 and 5 log reduction for S. aureus ATCC 25923 and S. aureus 1, respectively. Based on these findings, both PE seem to be promissory antimicrobial agents for upcoming use on dairy industry contaminations, BM and even S. aureus-triggered food poisoning. Further studies are needed to understand which of the compounds present in the extracts are responsible for the observed effects, including their corresponding modes of action.}, } @article {pmid31193467, year = {2019}, author = {Singhal, N and Maurya, AK and Singh, NS and Kumar, M and Virdi, JS}, title = {Antimicrobial resistance and its relationship with biofilm production and virulence-related factors in Yersinia enterocolitica biotype 1A.}, journal = {Heliyon}, volume = {5}, number = {5}, pages = {e01777}, pmid = {31193467}, issn = {2405-8440}, abstract = {The aim of the present study was to determine antimicrobial susceptibilities, biofilm production and, to discern a relationship between antimicrobial resistance, biofilm potential and virulence-related genes in strains of Yersinia entercocolitica biotype 1A. Thirty strains of Y. enterocolitica biotype 1A including clinical and non-clinical strains were investigated. Antimicrobial susceptibility for 15 antibiotics (representing different classes) was determined by disk-diffusion assay. Biofilm potential was determined on two different culture media using crystal violet assay. Also, a co-relation was studied between antimicrobial susceptibilities, biofilm production and virulence-related genes. All strains of biotype 1A produced biofilms and exhibited varied level of susceptibilities for different antibiotics. More than 60% of the strains were strong to moderate biofilm producers and, were exclusively associated with REP/ERIC clonal group B. Moderate and strong biofilm producers exhibited both sensitive and resistant phenotypes towards different antibiotics. Interestingly, weak biofilm producers were resistant to amoxicillin, amoxicillin-clavulanate and cefazolin. Analysis of antimicrobial susceptibilities, biofilm potential and virulence-related genes did not reveal any unequivocal relationships. The differential biofilm potential of Indian strains of Y. enterocolitica biotype 1A, suggests that biotype 1A strains are heterogeneous in nature.}, } @article {pmid31191696, year = {2019}, author = {Zaatout, N and Ayachi, A and Kecha, M}, title = {Interaction of primary mammary bovine epithelial cells with biofilm-forming staphylococci associated with subclinical bovine mastitis.}, journal = {Iranian journal of veterinary research}, volume = {20}, number = {1}, pages = {27-32}, pmid = {31191696}, issn = {1728-1997}, abstract = {BACKGROUND: Staphylococci are recognized worldwide as one of the most important etiological agents of bovine mastitis due to their virulence factors such as their ability to penetrate inside mammary epithelial cells and their ability to form biofilm.

AIMS: The objectives of this study were to establish a model of primary mammary epithelial cells originating from the secretory tissue of the bovine udder in order to evaluate the invasion ability of 42 staphylococci isolated from subclinical bovine mastitis cases.

METHODS: Two techniques were used to establish a model of primary mammary epithelial cells, the explant technique and the enzymatic method. Biofilm formation was detected using a quantitative spectrophotometric assay. When compared with the enzymatic digestion method, the epithelial cells obtained by the explant technique grew faster and reached quickly to confluence.

RESULTS: The results showed that 60% of Staphylococcus aureus isolates (n=12) were able to invade the epithelial cells and 72.7% of coagulase negative staphylococci (CNS) isolates were invasive (n=16). Staphylococcus xylosus isolates showed higher invasion values compared to S. aureus isolates and non-biofilm forming staphylococci were able to invade primary epithelial cells, but no significant difference was found between the internalization capabilities of biofilm positive and negative isolates.

CONCLUSION: The results show that the explant technique is a valuable method for developing primary epithelial cells without damaging the cells, and provides new insights regarding the ability of staphylococci to penetrate inside primary mammary epithelial cells.}, } @article {pmid31190904, year = {2019}, author = {Navidifar, T and Amin, M and Rashno, M}, title = {Effects of sub-inhibitory concentrations of meropenem and tigecycline on the expression of genes regulating pili, efflux pumps and virulence factors involved in biofilm formation by Acinetobacter baumannii.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {1099-1111}, pmid = {31190904}, issn = {1178-6973}, abstract = {Background: Sub-minimal inhibitory concentrations of antibiotics have been indicated to affect the biofilm formation in pathogens of nosocomial infections. This study aimed to investigate the effects of meropenem and tigecycline at their sub-minimum inhibitory concentrations (MICs) on the biofilm formation capacity of Acinetobacter baumannii (A. baumannii), as well as the expression levels of genes involved in biofilm formation, quorum sensing, pili assembly and efflux pumps. Materials and methods: In this study, four non-clonal strains (AB10, AB13, AB32 and AB55), which were different from the aspects of antibiotic susceptibility and biofilm formation from each other were selected for the evaluation of antimicrobial susceptibility, biofilm inducibility at sub-MICs of meropenem and tigecycline and the gene expression levels (the abaI, abaR, bap, pgaA, csuE, bfmS, bfmR, ompA, adeB, adeJ and adeG genes). Result: A significant increase in the MICs of all antibiotics was demonstrated in the biofilm cells in each four strains. The biofilm formation was significantly decreased in all the representative strains exposed to tigecycline. However, the biofilm inducibility at sub-MICs of meropenem was dependent on strain genotype. In concordance with these results, Pearson correlation analysis indicated a positive significant correlation between the biofilm formation capacity and the mRNA levels of genes encoding efflux pumps except adeJ, the genes involved in biofilm formation, pili assembly and quorum sensing following exposure to meropenem and tigecycline at their sub-MICs. Conclusion: These results revealed valuable data into the correlation between the gene transcription levels and biofilm formation, as well as quorum sensing and their regulation at sub-MICs of meropenem and tigecycline.}, } @article {pmid31188854, year = {2019}, author = {Meza-Villezcas, A and Gallego-Hernández, AL and Yildiz, FH and Jaime-Acuña, OE and Raymond-Herrera, O and Huerta-Saquero, A}, title = {Effect of antimicrobial nanocomposites on Vibrio cholerae lifestyles: Pellicle biofilm, planktonic and surface-attached biofilm.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0217869}, pmid = {31188854}, issn = {1932-6203}, support = {R01 AI114261/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Copper/chemistry ; Dental Pellicle/drug effects/microbiology ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Metal Nanoparticles/*chemistry/ultrastructure ; Microbial Sensitivity Tests ; Nanocomposites/*chemistry/ultrastructure ; Plankton/*drug effects/growth & development ; Silver/chemistry ; Transcription, Genetic ; Vibrio cholerae/*drug effects/growth & development/ultrastructure ; Zeolites/chemistry ; Zinc/chemistry ; }, abstract = {Vibrio cholerae is an important human pathogen causing intestinal disease with a high incidence in developing countries. V. cholerae can switch between planktonic and biofilm lifestyles. Biofilm formation is determinant for transmission, virulence and antibiotic resistance. Due to the enhanced antibiotic resistance observed by bacterial pathogens, antimicrobial nanomaterials have been used to combat infections by stopping bacterial growth and preventing biofilm formation. In this study, the effect of the nanocomposites zeolite-embedded silver (Ag), copper (Cu), or zinc (Zn) nanoparticles (NPs) was evaluated in V. cholerae planktonic cells, and in two biofilm states: pellicle biofilm (PB), formed between air-liquid interphase, and surface-attached biofilm (SB), formed at solid-liquid interfaces. Each nanocomposite type had a distinctive antimicrobial effect altering each V. cholerae lifestyles differently. The ZEO-AgNPs nanocomposite inhibited PB formation at 4 μg/ml, and prevented SB formation and eliminated planktonic cells at 8 μg/ml. In contrast, the nanocomposites ZEO-CuNPs and ZEO-ZnNPs affect V. cholerae viability but did not completely avoid bacterial growth. At transcriptional level, depending on the nanoparticles and biofilm type, nanocomposites modified the relative expression of the vpsL, rbmA and bap1, genes involved in biofilm formation. Furthermore, the relative abundance of the outer membrane proteins OmpT, OmpU, OmpA and OmpW also differs among treatments in PB and SB. This work provides a basis for further study of the nanomaterials effect at structural, genetic and proteomic levels to understand the response mechanisms of V. cholerae against metallic nanoparticles.}, } @article {pmid31187657, year = {2019}, author = {Salman, M and Rizwana, R and Khan, H and Munir, I and Hamayun, M and Iqbal, A and Rehman, A and Amin, K and Ahmed, G and Khan, M and Khan, A and Amin, FU}, title = {Synergistic effect of silver nanoparticles and polymyxin B against biofilm produced by Pseudomonas aeruginosa isolates of pus samples in vitro.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {47}, number = {1}, pages = {2465-2472}, doi = {10.1080/21691401.2019.1626864}, pmid = {31187657}, issn = {2169-141X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Polymyxin B/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Silver/chemistry/*pharmacology ; Suppuration/microbiology ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is an aerobic gram-negative, non-spore forming, rod-shaped bacterium. It accelerates the decline in lung function and ultimately leads to increased mortality and morbidity rate. Survival and virulence of P. aeruginosa is due to its biofilm formation ability. The main aim of this study was to test the synergistic effect of silver nanoparticles (AgNPs) in combination with Polymyxin B against biofilms of P. aeruginosa. A total of 500 pus aspirations were collected and bacterial pathogens were identified. Biofilm formation was attained using a glass tube method and microtiter plate assay. The minimum inhibitory concentration of Polymyxin B was determined using agar well diffusion method. Silver nanoparticles were synthesized by chemical reduction method followed by determination of their anti-pseudomonal ability separately and in combination with Polymyxin B using microtiter plate assay. Our results showed that 120 out of 500 samples were Pseudomonas positive. The ratio of multidrug-resistant (MDR) in our collected Pseudomonas samples was 83% (25/30). Generally, the minimum inhibitory concentration (MIC) of Polymyxin B was 16 µg/mL and that of AgNPs was null. However, AgNPs showed great synergistic effect in combination with Polymyxin B. Synergistically, the efficacy of Polymyxin B was enhanced four times as compared to unaided Polymyxin B.}, } @article {pmid31187647, year = {2019}, author = {Alavi, M and Karimi, N}, title = {Ultrasound assisted-phytofabricated Fe3O4 NPs with antioxidant properties and antibacterial effects on growth, biofilm formation, and spreading ability of multidrug resistant bacteria.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {47}, number = {1}, pages = {2405-2423}, doi = {10.1080/21691401.2019.1624560}, pmid = {31187647}, issn = {2169-141X}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Antioxidants/chemistry/pharmacology ; Bacteria/*drug effects/*growth & development ; Biofilms/*drug effects ; Biphenyl Compounds/chemistry ; Drug Resistance, Bacterial/*drug effects ; Drug Resistance, Multiple/*drug effects ; Magnetite Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Picrates/chemistry ; *Ultrasonic Waves ; }, abstract = {Complicated issue in infectious illnesses therapy is increasing of multidrug resistant (MDR) bacteria and biofilms in bacterial infections. In this way, emerging of nanotechnology as a new weapon specifically in the cases of metal nanoparticle (MNPs) synthesis and MNPs surface modification has obtained more attention. In this study, ultrasound-assisted green synthesis method was utilized for the preparation of Fe3O4 NPs with novel shape (dendrimer) through leaf aqueous extract of Artemisia haussknechtii Boiss. Ultraviolet-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopic (AFM), X-ray diffraction (XRD) techniques were applied for MNPs physicochemical characterization. Also, disc diffusion assay, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), planktonic and biofilm morphology of three pathogenic bacteria involving Serratia marcescens ATCC 13880, Escherichia coli ATCC 25922, and methicillin-resistant Staphylococcus aureus (MRSA) were evaluated upon treatment of Fe3O4 NPs as antiplanktonic and antibiofilm analysis. Results showed efficient antiplanktonic and antibiofilm activities of biosynthesized Fe3O4 NPs with average diameter size of 83.4 nm. Reduction in biofilm formation of S. aureus ATCC under Fe3O4 NPs stress was significant (66%) in higher MNPs concentration (100 μg/mL). In addition, as first report, spreading ability of S. aureus as important factor in colony expansion on culture medium was reduced by increasing of Fe3O4 NPs. Present study demonstrates striking antiplanktonic, antibiofilm, antispreading mobility and antioxidant aspects of one-pot biosynthesized Fe3O4 NPs with novel shape.}, } @article {pmid31187383, year = {2019}, author = {García-Rodríguez, JP and Amezquita-Garcia, HJ and Escamilla-Alvarado, C and Rangel-Mendez, JR and Gutiérrez-García, K}, title = {Biofilm microbial composition changes due to different surface chemical modifications of activated carbon cloths in the biotransformation of 4-nitrophenol.}, journal = {Biodegradation}, volume = {30}, number = {5-6}, pages = {401-413}, doi = {10.1007/s10532-019-09880-z}, pmid = {31187383}, issn = {1572-9729}, mesh = {Biodegradation, Environmental ; Biofilms ; *Bioreactors ; Biotransformation ; *Charcoal ; Nitrophenols ; RNA, Ribosomal, 16S ; Sewage ; Waste Disposal, Fluid ; }, abstract = {Activated carbon cloths (ACCs) were used as biofilms supports in the anaerobic biotransformation of 4-nitrophenol (4NP). As received ACC material (AW) was oxidized with HNO3 (OX) and then functionalized with anthraquinone-2,6-disulfonate (AQ). The three ACCs were packed in hybrid UASB reactors and seeded with anaerobic granular sludge for biotransformation experiments. The results indicated that ACC-packed bioreactors improved the biotransformation of 4NP by twofold as compared to the control reactor without support materials. However, the biotransformation effciency of AW, OX and AQ was very similar (59%), indicating the role of ACC as biofilm support and not as redox mediator. After 4NP biotransformation several physicochemical and biological changes were observed like (1) the point of zero charge (pHPZC) shift from acidic values (AW = 5.0, OX = 3.4, AQ = 3.1) to neutral values (pHPZC = 7.6 on average), (2) increase in the concentration of acidic and basic surface functional groups over ACC materials and the amount of supported biomass on ACCs due to biofilm formation, and (3) enrichment of exoelectrogenic microorganisms belonging to the genera Geobacter over carbonyl-rich ACC surface as revealed by 16S rRNA amplicon sequencing. Overall, the results suggest that chemical modifications of ACCs changed the microbial composition of the biofilm, but the higher concentration of carbonyl groups on ACC did not affect the biotransformation of 4NP.}, } @article {pmid31187378, year = {2019}, author = {Zou, H and Wang, Y}, title = {Functional collaboration of biofilm-cathode electrode and microbial fuel cell for biodegradation of methyl orange and simultaneous bioelectricity generation.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {22}, pages = {23061-23069}, pmid = {31187378}, issn = {1614-7499}, support = {1604f0704047//Research Items from the Department of Science and Technology of Anhui Province, China/ ; gxyqZD2016212//Special Foundation for Young Scientists of Anhui province, China/ ; }, mesh = {*Azo Compounds/chemistry ; Bacillus ; Biodegradation, Environmental ; Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes/*microbiology ; Electrolysis ; Wastewater ; Wetlands ; }, abstract = {A distinctive process (BCE-MFC) was developed to explore the methyl orange (MO) degradation and simultaneous bioelectricity generation based on the functional collaboration of biofilm, electrolysis, constructed wetland, and microbial fuel cell. The biofilm-cathode electrode-microbial fuel cell (BCE-MFC) was capable of sustaining an excellent MO removal (100%) and bioelectricity production (0.63 V). BCE significantly enhanced MO biodegradability, thus resulting in a 56.3% improvement of COD removal in subsequent MFC. Bacillus was dominant in biofilm on cathode in BCE. In MFC, Proteobacteria phylum (64.84%) and Exiguobacterium genus (13.30%) were predominated in the anode region, probably basically responsible for electricity generation. Interestingly, relatively high content of Heliothrix sp. (9.94%) was found in the MFC designed here, which was likely to participate in electricity production as well. The proposed functional collaboration may be an effective strategy in refractory wastewater treatment and power production.}, } @article {pmid31187338, year = {2019}, author = {Devadas, SM and Nayak, UY and Narayan, R and Hande, MH and Ballal, M}, title = {2,5-Dimethyl-4-hydroxy-3(2H)-furanone as an Anti-biofilm Agent Against Non-Candida albicans Candida Species.}, journal = {Mycopathologia}, volume = {184}, number = {3}, pages = {403-411}, pmid = {31187338}, issn = {1573-0832}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Blood/microbiology ; Candida/*drug effects/growth & development/isolation & purification ; Candidiasis/microbiology ; Catheters/microbiology ; Environmental Microbiology ; Furans/*pharmacology ; Humans ; Urine/microbiology ; }, abstract = {BACKGROUND: The predominance of non-Candida albicans Candida (NCAC) species causing healthcare-associated infections has increased over the last decade pertaining to their ability to form biofilms on medical devices. These biofilm-associated infections are challenging to treat as they are resistant to antifungal agents and evade host-immune response resulting in a high risk of device failure or biomaterial removal. Thus, to minimize the risk of biofilm-associated infections, preventing biofilm formation is the best approach which is mediated by the quorum quenching process.

METHODS: The present study investigated the modulatory effect of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) on NCAC biofilm formation and also assessed the effect of the DMHF-coated catheters on biofilm formation of NCAC. The NCAC isolates studied were Candida tropicalis, Candida glabrata and Candida krusei isolated from catheter tip, urine and blood, respectively.

RESULTS: DMHF at a concentration of 30 µg/mL showed an inhibitory effect against NCAC biofilms at various stages and was statistically significant (p ≤ 0.05) against the various concentrations (50-5 µg/mL) tested and also among the three phases of experiment. The furanone content on coated catheters ranged from 170 to 750 µg and release of furanone from the coated catheter was about 15 µg for 30 days. The effect of DMHF-coated catheters on NCAC biofilm formation was observed by the scanning electron microscopy which revealed the absence of NCAC adherence on DMHF-coated catheters.

DISCUSSION: This study provides a design to develop furanone-coated biomaterials which could be implemented in healthcare settings to reduce medical device-associated infections. The excellent biological performance, combined with their antimicrobial properties, suggests that 2,5-dimethyl-4-hydroxy-3(2H)-furanone could be an effective anti-infective coating for implantable devices.}, } @article {pmid31185817, year = {2019}, author = {Dzianach, PA and Dykes, GA and Strachan, NJC and Forbes, KJ and Pérez-Reche, FJ}, title = {Challenges of biofilm control and utilization: lessons from mathematical modelling.}, journal = {Journal of the Royal Society, Interface}, volume = {16}, number = {155}, pages = {20190042}, pmid = {31185817}, issn = {1742-5662}, mesh = {Biofilms/*growth & development ; *Computer Simulation ; *Models, Biological ; }, abstract = {This article reviews modern applications of mathematical descriptions of biofilm formation. The focus is on theoretically obtained results which have implications for areas including the medical sector, food industry and wastewater treatment. Examples are given as to how models have contributed to the overall knowledge on biofilms and how they are used to predict biofilm behaviour. We conclude that the use of mathematical models of biofilms has demonstrated over the years the ability to significantly contribute to the vast field of biofilm research. Among other things, they have been used to test various hypotheses on the nature of interspecies interactions, viability of biofilm treatment methods or forces behind observed biofilm pattern formations. Mathematical models can also play a key role in future biofilm research. Many models nowadays are analysed through computer simulations and continue to improve along with computational capabilities. We predict that models will keep on providing answers to important challenges involving biofilm formation. However, further strengthening of the ties between various disciplines is necessary to fully use the tools of collective knowledge in tackling the biofilm phenomenon.}, } @article {pmid31185326, year = {2019}, author = {Pourhajibagher, M and Ghorbanzadeh, R and Bahador, A}, title = {Antimicrobial properties of acrylic resins doped with Undaria pinnatifida exposed to light-emitting diode: In silico and in vitro assessments on multispecies biofilm-producing microbiota.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {210-215}, doi = {10.1016/j.pdpdt.2019.05.039}, pmid = {31185326}, issn = {1873-1597}, mesh = {Acrylic Resins/*chemistry ; Biofilms/*drug effects ; Candida albicans/drug effects ; Computer Simulation ; Dose-Response Relationship, Drug ; Ferredoxins/*pharmacology ; Lactobacillus acidophilus/drug effects ; Microbiological Techniques ; Oxidation-Reduction ; Phototherapy/*methods ; Staphylococcus/drug effects ; Streptococcus mutans/drug effects ; *Undaria ; }, abstract = {BACKGROUND: This study sought to evaluates the efficiency of anti-microbial activity of acrylic resins doped with different concentrations of Undaria pinnatifida after activation with light-emitting diode (LED) at producing photodynamic damage to multispecies biofilm-producing microbiome.

MATERIAL AND METHODS: In this study, bioinformatics tools and computer simulation molecular modeling were used to evaluate the capacity of ferredoxin (FDX), an electron acceptor in metabolic pathways of U. pinnatifida, which can discharge electrons produced from photo-excited chlorophyll-a (Chl-a) by LED irradiation. Acrylic resin discs containing different concentration of U. pinnatifida (0, 0.5, 1, and 2%) were fabricated and were subjected to LED irradiation immediately before each experiment. After continuously rinsed (up to 30 days), the antimicrobial activity of acrylic resins doped with U. pinnatifida following photo-activation was determined by disc agar diffusion, biofilm formation inhibition, and eluted component assays versus bacterial species linked to caries that constitute a mixed biofilm including Streptococcus mutans, S. sanguinis, and Lactobacillus acidophilus, as well as Candida albicans as main etiology of candidal stomatitis.

RESULTS: Modeling and a virtual screening analysis of FDX indicated that it is a stable protein with an iron-sulfur center that can discharge electrons produced from photo-excited Chl-a and transfers them to FDX-NADP[+] reductase for NADP[+] reduction in photosystem I, which is essential in the Calvin cycle for carbon assimilation. FDX acts as an electron transfer agent in the redox reactions. The results showed that growth inhibition zones were not seen around acrylic resin discs in any group. In biofilm test, the colony counts of all test microorganisms significantly decreased (36%-87%) by an increase in the percentage of U. pinnatifida in acrylic resins after photo-activation (P < 0.05). Acrylic resins doped with 2% wt. U. pinnatifida following photo-activation using LED was inhibited biofilm formation by the test microorganisms, up to 30 days of rinsing.

CONCLUSION: Based on the results presented here, an acrylic resin containing U. pinnatifida, even at the lowest concentration, following photo-activation using LED have antimicrobial properties against planktonic and biofilm forms of the cariogenic microorganisms as well as C. albicans.}, } @article {pmid31182496, year = {2019}, author = {Nicastro, LK and Tursi, SA and Le, LS and Miller, AL and Efimov, A and Buttaro, B and Tam, V and Tükel, Ç}, title = {Cytotoxic Curli Intermediates Form during Salmonella Biofilm Development.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31182496}, issn = {1098-5530}, support = {P30 CA006927/CA/NCI NIH HHS/United States ; R21 AI126133/AI/NIAID NIH HHS/United States ; R21 AI132996/AI/NIAID NIH HHS/United States ; R56 AI125429/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/*physiology ; Salmonella typhimurium/genetics/*metabolism/physiology ; }, abstract = {Enterobacteriaceae produce amyloid proteins called curli that are the major proteinaceous component of biofilms. Amyloids are also produced by humans and are associated with diseases such as Alzheimer's. During the multistep process of amyloid formation, monomeric subunits form oligomers, protofibrils, and finally mature fibrils. Amyloid β oligomers are more cytotoxic to cells than the mature amyloid fibrils. Oligomeric intermediates of curli had not been previously detected. We determined that turbulence inhibited biofilm formation and that, intriguingly, curli aggregates purified from cultures grown under high-turbulence conditions were structurally smaller and contained less DNA than curli preparations from cultures grown with less turbulence. Using flow cytometry analysis, we demonstrated that CsgA was expressed in cultures exposed to higher turbulence but that these cultures had lower levels of cell death than less-turbulent cultures. Our data suggest that the DNA released during cell death drives the formation of larger fibrillar structures. Consistent with this idea, addition of exogenous genomic DNA increased the size of the curli intermediates and led to binding to thioflavin T at levels observed with mature aggregates. Similar to the intermediate oligomers of amyloid β, intermediate curli aggregates were more cytotoxic than the mature curli fibrils when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.IMPORTANCE Amyloid proteins are the major proteinaceous components of biofilms, which are associated with up to 65% of human bacterial infections. Amyloids produced by human cells are also associated with diseases such as Alzheimer's. The amyloid monomeric subunits self-associate to form oligomers, protofibrils, and finally mature fibrils. Amyloid β oligomers are more cytotoxic to cells than the mature amyloid fibrils. Here we detected oligomeric intermediates of curli for the first time. Like the oligomers of amyloid β, intermediate curli fibrils were more cytotoxic than the mature curli fibrillar aggregates when incubated with bone marrow-derived macrophages. The discovery of cytotoxic curli intermediates will enable research into the roles of amyloid intermediates in the pathogenesis of Salmonella and other bacteria that cause enteric infections.}, } @article {pmid31181853, year = {2019}, author = {Lotlikar, SR and Gallaway, E and Grant, T and Popis, S and Whited, M and Guragain, M and Rogers, R and Hamilton, S and Gerasimchuk, NG and Patrauchan, MA}, title = {Polymeric Composites with Silver (I) Cyanoximates Inhibit Biofilm Formation of Gram-Positive and Gram-Negative Bacteria.}, journal = {Polymers}, volume = {11}, number = {6}, pages = {}, pmid = {31181853}, issn = {2073-4360}, support = {1R15AI088594-01A1//National Institutes of Health/ ; CC 6598//Cottrell College Research Corporation/ ; }, abstract = {Biofilms are surface-associated microbial communities known for their increased resistance to antimicrobials and host factors. This resistance introduces a critical clinical challenge, particularly in cases associated with implants increasing the predisposition for bacterial infections. Preventing such infections requires the development of novel antimicrobials or compounds that enhance bactericidal effect of currently available antibiotics. We have synthesized and characterized twelve novel silver(I) cyanoximates designated as Ag(ACO), Ag(BCO), Ag(CCO), Ag(ECO), Ag(PiCO), Ag(PICO) (yellow and red polymorphs), Ag(BIHCO), Ag(BIMCO), Ag(BOCO), Ag(BTCO), Ag(MCO) and Ag(PiPCO). The compounds exhibit a remarkable resistance to high intensity visible light, UV radiation and heat and have poor solubility in water. All these compounds can be well incorporated into the light-curable acrylate polymeric composites that are currently used as dental fillers or adhesives of indwelling medical devices. A range of dry weight % from 0.5 to 5.0 of the compounds was tested in this study. To study the potential of these compounds in preventing planktonic and biofilm growth of bacteria, we selected two human pathogens (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and Gram-positive environmental isolate Bacillus aryabhattai. Both planktonic and biofilm growth was abolished completely in the presence of 0.5% to 5% of the compounds. The most efficient inhibition was shown by Ag(PiCO), Ag(BIHCO) and Ag(BTCO). The inhibition of biofilm growth by Ag(PiCO)-yellow was confirmed by scanning electron microscopy (SEM). Application of Ag(BTCO) and Ag(PiCO)-red in combination with tobramycin, the antibiotic commonly used to treat P. aeruginosa infections, showed a significant synergistic effect. Finally, the inhibitory effect lasted for at least 120 h in P. aeruginosa and 36 h in S. aureus and B. aryabhattai. Overall, several silver(I) cyanoximates complexes efficiently prevent biofilm development of both Gram-negative and Gram-positive bacteria and present a particularly significant potential for applications against P. aeruginosa infections.}, } @article {pmid31181494, year = {2019}, author = {Yang, S and Guo, B and Shao, Y and Mohammed, A and Vincent, S and Ashbolt, NJ and Liu, Y}, title = {The value of floc and biofilm bacteria for anammox stability when treating ammonia-rich digester sludge thickening lagoon supernatant.}, journal = {Chemosphere}, volume = {233}, number = {}, pages = {472-481}, doi = {10.1016/j.chemosphere.2019.05.287}, pmid = {31181494}, issn = {1879-1298}, mesh = {Ammonia/*analysis ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification/genetics ; Genes, Bacterial ; Models, Theoretical ; Planctomycetales/genetics ; Sewage/*microbiology ; Water Purification/*methods ; }, abstract = {Ammonia-rich lagoon supernatant was treated using anammox process in an integrated fixed-film activated sludge (IFAS) laboratory reactor. Effective anammox activities were demonstrated over 259 days of operation. The ammonium removal efficiency reached 94% in Phase I with influent concentrations of NH4[+], NO2[-] and chemical oxygen demand (COD) at 250 mg-N/L, 325 mg-N/L, and 145 mg-COD/L, and reached 88% in Phase II at 420 mg-N/L, 525 mg-N/L, and 305 mg-COD/L. When supplemented with nitritation effluent for nitrite sources in Phase III, the influent COD concentration increased to 583 mg-COD/L without loss of ammonia removal efficiency (87%). The specific anammox activity was higher in biofilm than in the suspended flocs (P < 0.05), increased from Phase I to II (P < 0.05), and decreased in Phase III. Ammonia removal related genes were quantified using qPCR. Results showed higher anammox gene (AMX nirS) prevalence in biofilm, while denitrification genes (nosZ and narG) were higher in flocs (P < 0.05). Microbial community analysis showed that the seeded anammox bacteria Candidatus Brocadia was maintained at 19% in the biofilm and only 0.3% in the flocs. The major taxa in the flocs were related to denitrifiers. The floc community was affected largely under high COD conditions, but the biofilm community was not. These results suggest that the anammox activity in biofilm is resilient to high COD loadings, due to the existence of flocs with denitrification activity. The segregation of bacterial communities between biofilm and flocs in the anammox IFAS system resulted in high ammonia removal efficiency and resistance to high organic loadings.}, } @article {pmid31180246, year = {2021}, author = {Liu, J and Jiang, J and Zong, J and Li, B and Pan, T and Diao, Y and Zhang, Z and Zhang, X and Lu, M and Wang, S}, title = {Antibacterial and anti-biofilm effects of fatty acids extract of dried Lucilia sericata larvae against Staphylococcus aureus and Streptococcus pneumoniae in vitro.}, journal = {Natural product research}, volume = {35}, number = {10}, pages = {1702-1705}, doi = {10.1080/14786419.2019.1627353}, pmid = {31180246}, issn = {1478-6427}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antioxidants/pharmacology ; Biofilms/*drug effects ; Diptera/*chemistry ; Fatty Acids/chemistry/*pharmacology ; Larva/chemistry ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects ; Streptococcus pneumoniae/*drug effects ; }, abstract = {Development of new effective antimicrobial drugs is still a big challenge to date due to microbial infection remains an inevitable problem against human health. In this study, fatty acids extract of Lucilia sericata larvae (LFAs) was obtained and evaluated by gas chromatograph-mass spectrometry (GC-MS), and its antibacterial activity against Staphylococcus aureus (S. aureus) and Streptococcus pneumoniae (S. pneumoniae) was investigated. We found that LFAs exhibited effective antibacterial activity against S. aureus and S. pneumoniae with minimal inhibitory concentrations (MICs) of 125 μg/mL and 100 μg/mL, respectively. The bacterial wall and membrane were the main targets, which was confirmed by fluorescence microscopy, scanning electron microscopy and transmission electron microscopy. Furthermore, a notable anti-biofilm activity against S. aureus and S. pneumoniae was also observed, which was able to both prevent biofilm formation and eradicate mature biofilms of these bacteria. As a promising antibacterial agent, LFAs showed good application prospects in clinical practice.}, } @article {pmid31180065, year = {2019}, author = {Lahiri, D and Dash, S and Dutta, R and Nag, M}, title = {Elucidating the effect of anti-biofilm activity of bioactive compounds extracted from plants.}, journal = {Journal of biosciences}, volume = {44}, number = {2}, pages = {}, pmid = {31180065}, issn = {0973-7138}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects/growth & development/pathogenicity ; Biofilms/*drug effects/growth & development ; Host-Pathogen Interactions/drug effects ; Humans ; Microbial Sensitivity Tests ; Phytochemicals/chemistry/*pharmacology ; Plants/chemistry ; }, } @article {pmid31179649, year = {2019}, author = {Liu, L and Ye, C and Soteyome, T and Zhao, X and Xia, J and Xu, W and Mao, Y and Peng, R and Chen, J and Xu, Z and Shirtliff, ME and Harro, JM}, title = {Inhibitory effects of two types of food additives on biofilm formation by foodborne pathogens.}, journal = {MicrobiologyOpen}, volume = {8}, number = {9}, pages = {e00853}, pmid = {31179649}, issn = {2045-8827}, mesh = {Acrolein/analogs & derivatives/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Escherichia coli O157/*drug effects ; Food Additives/*pharmacology ; Microbial Sensitivity Tests ; Sodium Citrate/pharmacology ; Staphylococcus aureus/*drug effects ; Time Factors ; }, abstract = {The inhibition of microbial biofilms is a significant concern in food safety. In the present study, the inhibitory effect of sodium citrate and cinnamic aldehyde on biofilm formation at minimum inhibitory concentrations (MICs) and sub-MICs was investigated for Escherichia coli O157:H7 and Staphylococcus aureus. The biofilm inhibition rate was measured to evaluate the effect of sodium citrate on S. aureus biofilms at 24, 48, 72, and 96 hr. According to the results, an antibiofilm effect was shown by both food additives, with 10 mg/ml of sodium citrate exhibiting the greatest inhibition of S. aureus biofilms at 24 hr (inhibition rate as high as 77.51%). These findings strongly suggest that sodium citrate exhibits a pronounced inhibitory effect on biofilm formation with great potential in the extension of food preservation and storage.}, } @article {pmid31177828, year = {2019}, author = {Yunda, E and Quilès, F}, title = {In situ spectroscopic analysis of Lactobacillus rhamnosus GG flow on an abiotic surface reveals a role for nutrients in biofilm development.}, journal = {Biofouling}, volume = {35}, number = {5}, pages = {494-507}, doi = {10.1080/08927014.2019.1617279}, pmid = {31177828}, issn = {1029-2454}, mesh = {*Biofilms/drug effects ; Lacticaseibacillus rhamnosus/drug effects/*physiology ; Nutrients/*pharmacology ; Spectrum Analysis ; }, abstract = {In this work, infrared spectroscopy was used to monitor the changes in the biochemical composition of biofilms of the probiotic bacterium Lactobacillus rhamnosus GG (LGG) in three nutritive media (10-fold diluted MRS, AOAC, and mTSB), in situ and under flow conditions. Epifluorescence microscopy was used to observe the shape of LGG cells and their distribution on the surface. Spectroscopic fingerprints recorded as a function of time revealed a medium-dependent content of nucleic acids, phospholipids and polysaccharides in the biofilms. In addition, time-dependent synthesis of lactic acid was observed in MRS/10 and AOAC/10. Polysaccharides were produced to the highest extent in mTSB/10, and the biofilms obtained were the densest in this medium. The rod shape of the cells was preserved in MRS/10, whereas acidic stress induced in AOAC/10 and the nutritional quality of mTSB/10 led to strong morphological changes. These alterations due to the nutritive environment are important to consider in research and use of LGG biofilms.}, } @article {pmid31177008, year = {2019}, author = {Pousti, M and Lefèvre, T and Amirdehi, MA and Greener, J}, title = {A surface spectroscopy study of a Pseudomonas fluorescens biofilm in the presence of an immobilized air bubble.}, journal = {Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy}, volume = {222}, number = {}, pages = {117163}, doi = {10.1016/j.saa.2019.117163}, pmid = {31177008}, issn = {1873-3557}, mesh = {Air Microbiology ; Biofilms/*growth & development ; Equipment Design ; Microfluidic Analytical Techniques/*instrumentation ; Pseudomonas fluorescens/*physiology ; Spectroscopy, Fourier Transform Infrared/*instrumentation ; }, abstract = {A linear spectral mapping technique was applied to monitor the growth of biomolecular absorption bands at the bio-interface of a nascent Pseudomonas fluorescens biofilm during and after interaction with a surface-adhered air bubble. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra were obtained in different locations in a microchannel with adequate spatial and temporal resolution to study the effect of a static bubble on the evolution of protein and lipid signals at the ATR crystal surface. The results reveal that the presence of a bubble during the lag phase modified levels of extracellular lipids and affected a surface restructuring process, many hours after the bubble's disappearance.}, } @article {pmid31174686, year = {2019}, author = {Shah, MS and Qureshi, S and Kashoo, Z and Farooq, S and Wani, SA and Hussain, MI and Banday, MS and Khan, AA and Gull, B and Habib, A and Khan, SM and Dar, BA}, title = {Methicillin resistance genes and in vitro biofilm formation among Staphylococcus aureus isolates from bovine mastitis in India.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {64}, number = {}, pages = {117-124}, doi = {10.1016/j.cimid.2019.02.009}, pmid = {31174686}, issn = {1878-1667}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cattle ; Female ; India ; Mastitis, Bovine/*microbiology ; Methicillin/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*genetics ; Microbial Sensitivity Tests ; Milk/*microbiology ; Penicillin-Binding Proteins/genetics ; Staphylococcal Infections/*veterinary ; }, abstract = {INTRODUCTION: Biofilms, an assemblage of microbial cells irreversibly associated with a surface and enclosed in a matrix of polysaccharide material pose serious health challenges, resulting in high economic losses. The emergence of methicillin-resistant S. aureus (MRSA) infections and ability to form biofilms in dairy animals is of emerging concern for livestock and public health owing to their association with serious infections. The present study was undertaken to examine the presence of methicillin resistance genes among the biofilm forming Staphylococcus aureus strains isolated from cases of acute and subacute bovine mastitis. A total of 150 mastitic milk samples referred to Veterinary Clinical Complex, Shuhama (Aulesteng) SKUAST-K were screened in present study. The methicillin resistant Staphylococcus aureus isolates were also screened for in vitro biofilm forming ability.

RESULTS: A total of 80 (53.33%) S. aureus isolates were recovered from cases of bovine mastitis of which 20 (25%) were methicillin (mecA) gene positive. Of the 20 mecA positive isolates, 20% were positive for SCCmec I, 35% for SCCmec IV and 45% for SCCmec V subtypes. In vitro antibiotic sensitivity testing of MRSA revealed complete resistance towards methicillin and other pencillin group of antibiotics.

CONCLUSION: A significant correlation was observed between in vitro biofilm formation and presence of methicillin resistance gene in S aureus isolates recovered from acute and subacute mastitis. The Staphylococcus aureus isolates positive for methicillin resistance gene (mecA) were either strong or moderate biofilm formers.}, } @article {pmid31173863, year = {2019}, author = {Rajasekharan, SK and Lee, JH and Lee, J}, title = {Aripiprazole repurposed as an inhibitor of biofilm formation and sterol biosynthesis in multidrug-resistant Candida albicans.}, journal = {International journal of antimicrobial agents}, volume = {54}, number = {4}, pages = {518-523}, doi = {10.1016/j.ijantimicag.2019.05.016}, pmid = {31173863}, issn = {1872-7913}, mesh = {Antifungal Agents/*pharmacology ; Aripiprazole/*pharmacology ; Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/growth & development ; Cell Adhesion/drug effects ; Dose-Response Relationship, Drug ; *Drug Repositioning ; Hyphae/drug effects/growth & development ; Microbial Sensitivity Tests ; Sterols/*antagonists & inhibitors ; }, abstract = {Drug repurposing is an anticipative chemotherapeutic strategy that accentuates the inadequacy of antifungal drugs. The study identifies an antipsychotic drug, aripiprazole, as a biofilm and hyphal inhibitor of Candida albicans. Microtitre plate biofilm inhibition, metabolic activity and hyphal inhibitory assays were used to assess the potency of aripiprazole; and filipin staining, reactive oxygen species staining, cAMP rescue, propidium iodide staining, computational studies and qRT-PCR assays were used to elucidate its mode of action. The study revealed aripiprazole functioned in a manner similar to standard azoles, particularly the imidazole, ketoconazole, by inhibiting pseudohyphal formation during the early stages of hyphal development. The action of aripiprazole on C. albicans was dose-dependent and it exhibited varied mechanisms of action at low and high dosages. At low dosage, aripiprazole outperformed ketoconazole in terms of inhibiting biofilm formation, hyphal filamentations, and yeast flocculation, whereas at higher dosage it mimicked ketoconazole. This study illustrates the anti-candidal potential and mechanistic activities of aripiprazole, and indicates the future use of this drug as an anti-biofilm agent.}, } @article {pmid31173560, year = {2019}, author = {Kreth, J and Ferracane, JL and Pfeifer, CS and Khajotia, S and Merritt, J}, title = {At the Interface of Materials and Microbiology: A Call for the Development of Standardized Approaches to Assay Biomaterial-Biofilm Interactions.}, journal = {Journal of dental research}, volume = {98}, number = {8}, pages = {850-852}, pmid = {31173560}, issn = {1544-0591}, support = {K02 DE025280/DE/NIDCR NIH HHS/United States ; R56 DE021726/DE/NIDCR NIH HHS/United States ; R15 DE019940/DE/NIDCR NIH HHS/United States ; R01 DE026113/DE/NIDCR NIH HHS/United States ; U01 DE023756/DE/NIDCR NIH HHS/United States ; R01 DE021726/DE/NIDCR NIH HHS/United States ; R35 DE028252/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biocompatible Materials ; *Biofilms ; Composite Resins ; Dental Caries ; *Dental Materials ; Humans ; Materials Testing ; Models, Biological ; Streptococcus mutans ; }, } @article {pmid31172798, year = {2021}, author = {Dell'Olmo, E and Gaglione, R and Pane, K and Sorbo, S and Basile, A and Esposito, S and Arciello, A}, title = {Fighting multidrug resistance with a fruit extract: anti-cancer and anti-biofilm activities of Acca sellowiana.}, journal = {Natural product research}, volume = {35}, number = {10}, pages = {1686-1689}, doi = {10.1080/14786419.2019.1624961}, pmid = {31172798}, issn = {1478-6427}, mesh = {Acetone/chemistry ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antineoplastic Agents, Phytogenic/chemistry/*pharmacology ; Biofilms/drug effects ; Cell Line, Tumor ; Drug Resistance, Bacterial/drug effects ; Drug Resistance, Neoplasm/*drug effects ; Feijoa/*chemistry ; Fruit/chemistry ; Humans ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/*pharmacology ; }, abstract = {In this study, the efficacy of Acca sellowiana fruit acetonic extract on human MDR cancer cells was tested for the first time, and it was demonstrated that the fruit extract is effective on both sensitive and resistant tumor cells. The effects of A. sellowiana extract on bacterial biofilm were also examined for the first time. By crystal violet assays and confocal microscopy analyses, it was demonstrated that the plant extract is able to strongly inhibit biofilm formation of both sensitive and resistant bacterial strains. Furthermore, antimicrobial activity assays and TEM analyses clearly demonstrated the effectiveness of plant extract on planktonic bacterial cells in both sensitive and resistant strains. Altogether, these findings intriguingly expand the panel of activities of A. sellowiana fruit extract with respect to previous reports, and open interesting perspectives to its therapeutic applications.}, } @article {pmid31171741, year = {2019}, author = {Shakibaie, M and Hajighasemi, E and Adeli-Sardou, M and Doostmohammadi, M and Forootanfar, H}, title = {Antimicrobial and anti-biofilm activities of Bi subnitrate and BiNPs produced by Delftia sp. SFG against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis.}, journal = {IET nanobiotechnology}, volume = {13}, number = {4}, pages = {377-381}, pmid = {31171741}, issn = {1751-875X}, mesh = {Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Bismuth/chemistry/metabolism/*pharmacology ; Delftia/*chemistry/metabolism ; Microbial Sensitivity Tests ; Nanoparticles/chemistry/metabolism/*toxicity ; Plant Extracts/chemistry/metabolism ; }, abstract = {In the present study Delftia sp. Shakibaie, Forootanfar, and Ghazanfari (SFG), was applied for preparation of biogenic Bi nanoparticles (BiNPs) and antibacterial and anti-biofilm activities of the purified BiNPs were investigated by microdilution and disc diffusion methods. Transmission electron micrographs showed that the produced nanostructures were spherical with a size range of 40-120 nm. The measured minimum inhibitory concentration of both the Bi subnitrate and BiNPs against three biofilms producing bacterial pathogens of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were found to be above 1280 µg/ml. Addition of BiNPs (1000 µg/disc) to antibiotic discs containing tobramycin, nalidixic acid, ceftriaxone, bacitracin, cefalexin, amoxicillin, and cefixime significantly increased the antibacterial effects against methicillin-resistant S. aureus (MRSA) in comparison with Bi subnitrate (p < 0.05). Furthermore, the biogenic BiNPs decreased the biofilm formation of S. aureus, P. aeruginosa, and P. mirabilis to 55, 85, and 15%, respectively. In comparison to Bi subnitrate, BiNPs indicated significant anti-biofilm activity against P. aeruginosa (p < 0.05) while the anti-biofilm activity of BiNPs against S. aureus and P. mirabilis was similar to that of Bi subnitrate. To sum up, the attained results showed that combination of biogenic BiNPs with commonly used antibiotics relatively enhanced their antibacterial effects against MRSA.}, } @article {pmid31170510, year = {2019}, author = {Kłodzińska, SN and Pletzer, D and Rahanjam, N and Rades, T and Hancock, REW and Nielsen, HM}, title = {Hyaluronic acid-based nanogels improve in vivo compatibility of the anti-biofilm peptide DJK-5.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {20}, number = {}, pages = {102022}, doi = {10.1016/j.nano.2019.102022}, pmid = {31170510}, issn = {1549-9642}, mesh = {Abscess/pathology ; Animals ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects ; Hyaluronic Acid/chemistry/*pharmacology ; Mice ; Nanogels/*chemistry/ultrastructure ; Oligopeptides/chemistry/*pharmacology ; Reactive Nitrogen Species/metabolism ; Reactive Oxygen Species/metabolism ; Skin/drug effects ; Subcutaneous Tissue/drug effects/pathology ; }, abstract = {Anti-biofilm peptides are a subset of antimicrobial peptides and represent promising broad-spectrum agents for the treatment of bacterial biofilms, though some display host toxicity in vivo. Here we evaluated nanogels composed of modified hyaluronic acid for the encapsulation of the anti-biofilm peptide DJK-5 in vivo. Nanogels of 174 to 194 nm encapsulating 33-60% of peptide were created. Efficacy and toxicity of the nanogels were tested in vivo employing a murine abscess model of a Pseudomonas aeruginosa LESB58 high bacterial density infection. The dose of DJK-5 that could be administered intravenously to mice without inducing toxicity was more than doubled after encapsulation in nanogels. Upon subcutaneous administration, the toxicity of the DJK-5 in nanogels was decreased four-fold compared to non-formulated peptide, without compromising the anti-abscess effect of DJK-5. These findings support the use of nanogels to increase the safety of antimicrobial and anti-biofilm peptides after intravenous and subcutaneous administration.}, } @article {pmid31169511, year = {2019}, author = {Mendoza, MV and Sáez, RT}, title = {Modelling biofilm anaerobic reactor with effluent from hydrolytic/acidogenic reactor as substrate.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {79}, number = {8}, pages = {1534-1540}, doi = {10.2166/wst.2019.152}, pmid = {31169511}, issn = {0273-1223}, mesh = {Anaerobiosis ; Bacteria ; *Biofilms ; Bioreactors/*statistics & numerical data ; Hydrolysis ; Methane ; *Models, Statistical ; Waste Disposal, Fluid/*statistics & numerical data ; }, abstract = {This work presents modelling of an anaerobic biofilm reactor using ceramic bricks as support. The results were compared with the experimental data. It was observed that the substrate concentration curves showed the same tendency. The methane formation curves showed significant differences. The substrate removal efficiency was 83%. In the steady state, the experimental data were higher than the model, from the result the substrate degrading bacteria grew enough to reach biofilm and that the effect of the shear stress was more significant as the biofilm increased in thickness. To the methane production, the model in steady state reached a maximum value of 0.56 m[3] CH4/m[3] *d and the experimental data reached 0.42 (m[3] CH4/m[3] * d). The biofilm thickness calculated by the model was 14 μm.}, } @article {pmid31169162, year = {2019}, author = {Kriswandini, IL and Rahardjo, MB and Budi, HS and Amalia, R}, title = {The difference in biofilm molecular weight in Streptococcus mutans and Aggregatibacter actinomycetemcomitans induced by sucrose and soy protein (glycine soja).}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {30}, number = {2}, pages = {273-276}, doi = {10.4103/ijdr.IJDR_183_17}, pmid = {31169162}, issn = {1998-3603}, mesh = {*Aggregatibacter actinomycetemcomitans ; Biofilms ; Extracellular Polymeric Substance Matrix ; Glycine ; Molecular Weight ; Soybean Proteins ; *Streptococcus mutans ; Sucrose ; }, abstract = {CONTEXT: Biofilms consist of microbial cells and extracellular polymeric substance (EPS). Streptococcus mutans and Aggregatibacter actinomycetemcomtans are bacteria that can form biofilms and generate EPS. Biofilm formation can be induced by specific substances such as sucrose and protein.

AIMS: To identify the molecular weight that determines biofilm protein profile expression of S. mutans and A. actinomycetemcomitans induced by sucrose (carbohydrate) and soy protein (glycine soja).

SETTINGS AND DESIGN: Experimental laboratory study.

MATERIALS AND METHODS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine the molecular weight.

STATISTICAL ANALYSIS USED: Nil.

RESULTS: The results of analysis of protein SDS-PAGE showed the presence of 28 protein bands on A. actinomycetemcomitans biofilm in the media trypticase soy broth (TSB), 20 protein bands on biofilms of S. mutans in the media TSB, 29 protein bands on biofilm A. actinomycetemcomitans in the media brain heart infusion (BHI) + sucrose 2%, and 13 protein bands on biofilms of S. mutans in the media BHI + sucrose 2%.

CONCLUSION: There are differences in biofilm protein profile expression that determine the molecular weight of S. mutans biofilm and A. actinomycetemcomitans induced by sucrose (carbohydrate) and soy protein (glycine soja).}, } @article {pmid31167793, year = {2019}, author = {Le Mauff, F and Bamford, NC and Alnabelseya, N and Zhang, Y and Baker, P and Robinson, H and Codée, JDC and Howell, PL and Sheppard, DC}, title = {Molecular mechanism of Aspergillus fumigatus biofilm disruption by fungal and bacterial glycoside hydrolases.}, journal = {The Journal of biological chemistry}, volume = {294}, number = {28}, pages = {10760-10772}, pmid = {31167793}, issn = {1083-351X}, support = {FDN-154327//CIHR/Canada ; P41 GM103473/GM/NIGMS NIH HHS/United States ; FDN-159902//CIHR/Canada ; 81361//CIHR/Canada ; P30 EB009998/EB/NIBIB NIH HHS/United States ; 123306//CIHR/Canada ; 43998//CIHR/Canada ; P41 RR012408/RR/NCRR NIH HHS/United States ; }, mesh = {Anti-Infective Agents/metabolism ; Aspergillus fumigatus/metabolism ; Biofilms/*drug effects/growth & development ; Catalytic Domain ; Fungal Proteins/metabolism ; Fungi/metabolism ; Glycoside Hydrolases/*metabolism/physiology ; Hydrolysis ; Polysaccharide-Lyases/metabolism/*ultrastructure ; Polysaccharides/metabolism ; Pseudomonas aeruginosa/metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods ; Substrate Specificity/physiology ; Virulence ; }, abstract = {During infection, the fungal pathogen Aspergillus fumigatus forms biofilms that enhance its resistance to antimicrobials and host defenses. An integral component of the biofilm matrix is galactosaminogalactan (GAG), a cationic polymer of α-1,4-linked galactose and partially deacetylated N-acetylgalactosamine (GalNAc). Recent studies have shown that recombinant hydrolase domains from Sph3, an A. fumigatus glycoside hydrolase involved in GAG synthesis, and PelA, a multifunctional protein from Pseudomonas aeruginosa involved in Pel polysaccharide biosynthesis, can degrade GAG, disrupt A. fumigatus biofilms, and attenuate fungal virulence in a mouse model of invasive aspergillosis. The molecular mechanisms by which these enzymes disrupt biofilms have not been defined. We hypothesized that the hydrolase domains of Sph3 and PelA (Sph3h and PelAh, respectively) share structural and functional similarities given their ability to degrade GAG and disrupt A. fumigatus biofilms. MALDI-TOF enzymatic fingerprinting and NMR experiments revealed that both proteins are retaining endo-α-1,4-N-acetylgalactosaminidases with a minimal substrate size of seven residues. The crystal structure of PelAh was solved to 1.54 Å and structure alignment to Sph3h revealed that the enzymes share similar catalytic site residues. However, differences in the substrate-binding clefts result in distinct enzyme-substrate interactions. PelAh hydrolyzed partially deacetylated substrates better than Sph3h, a finding that agrees well with PelAh's highly electronegative binding cleft versus the neutral surface present in Sph3h Our insight into PelAh's structure and function necessitate the creation of a new glycoside hydrolase family, GH166, whose structural and mechanistic features, along with those of GH135 (Sph3), are reported here.}, } @article {pmid31166981, year = {2019}, author = {Pinto, M and Langer, TM and Hüffer, T and Hofmann, T and Herndl, GJ}, title = {The composition of bacterial communities associated with plastic biofilms differs between different polymers and stages of biofilm succession.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0217165}, pmid = {31166981}, issn = {1932-6203}, mesh = {Bacteria/classification/drug effects/genetics ; Biofilms/*drug effects/growth & development ; Microbiota/*drug effects/genetics/*physiology ; Phylogeny ; Plastics/*pharmacology ; Sequence Analysis, DNA ; }, abstract = {Once in the ocean, plastics are rapidly colonized by complex microbial communities. Factors affecting the development and composition of these communities are still poorly understood. Additionally, whether there are plastic-type specific communities developing on different plastics remains enigmatic. We determined the development and succession of bacterial communities on different plastics under ambient and dim light conditions in the coastal Northern Adriatic over the course of two months using scanning electron microscopy and 16S rRNA gene analyses. Plastics used were low- and high-density polyethylene (LDPE and HDPE, respectively), polypropylene (PP) and polyvinyl chloride with two typical additives (PVC DEHP and PVC DINP). The bacterial communities developing on the plastics clustered in two groups; one group was found on PVC and the other group on all the other plastics and on glass, which was used as an inert control. Specific bacterial taxa were found on specific surfaces in essentially all stages of biofilm development and in both ambient and dim light conditions. Differences in bacterial community composition between the different plastics and light exposures were stronger after an incubation period of one week than at the later stages of the incubation. Under both ambient and dim light conditions, one part of the bacterial community was common on all plastic types, especially in later stages of the biofilm development, with families such as Flavobacteriaceae, Rhodobacteraceae, Planctomycetaceae and Phyllobacteriaceae presenting relatively high relative abundances on all surfaces. Another part of the bacterial community was plastic-type specific. The plastic-type specific fraction was variable among the different plastic types and was more abundant after one week of incubation than at later stages of the succession.}, } @article {pmid31166551, year = {2019}, author = {Pires, JG and Braga, AS and Andrade, FB and Saldanha, LL and Dokkedal, AL and Oliveira, RC and Magalhães, AC}, title = {Effect of hydroalcoholic extract of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on the viability and activity of microcosm biofilm and on enamel demineralization.}, journal = {Journal of applied oral science : revista FOB}, volume = {27}, number = {}, pages = {e20180514}, pmid = {31166551}, issn = {1678-7765}, mesh = {Anacardiaceae/*chemistry ; Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cariostatic Agents/pharmacology ; Cattle ; Colony Count, Microbial ; Dental Enamel/drug effects/microbiology ; Lactic Acid/metabolism ; Lactobacillus/drug effects ; Male ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microradiography/methods ; Myrtales/*chemistry ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Polysaccharides, Bacterial/metabolism ; Reproducibility of Results ; Saliva/chemistry ; Streptococcus mutans/drug effects ; Tooth Demineralization/*prevention & control ; }, abstract = {OBJECTIVES: The aim of this study was to assess the effect of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves hydroalcoholic extracts on viability and metabolism of a microcosm biofilm and on enamel demineralization prevention.

METHODOLOGY: Microcosm biofilm was produced on bovine enamel using inoculum from pooled human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. The biofilm was daily-treated with the extracts for 1 min. At the end, it was analyzed with respect to viability by fluorescence, CFU counting and extracellular polysaccharides (phenol-sulphuric acid colorimetric assay) and lactic acid (enzymatic assay) production. The demineralization was measured by TMR. The data were compared using ANOVA or Kruskal-Wallis (p<0.05).

RESULTS: M. urundeuva All. at 100, 10 and 0.1 μg/mL and Q. grandiflora Mart. at 100 and 0.1 μg/mL reduced biofilm viability similarly to positive control (chlorhexidine) and significantly more than the negative-vehicle control (35% ethanol). M. urundeuva at 1000, 100 and 0.1 μg/mL were able to reduce both lactobacilli and mutans streptococci CFU counting, while Q. grandiflora (1000 and 1.0 μg/mL) significantly reduced mutans streptococci CFU counting. On the other hand, the natural extracts were unable to significantly reduce extracellular polysaccharides and lactic acid productions neither the development of enamel carious lesions.

CONCLUSIONS: The extracts showed antimicrobial properties on microcosm biofilm, however, they had no effect on biofilm metabolism and caries protection.}, } @article {pmid31166390, year = {2019}, author = {Távora, FFF and Chocano, APC and Oliveira, DG and Pereira, JR and Almeida, RS and Neppelenbroek, KH and Porto, VC}, title = {Beneficial Effects of Ethyl-Cyanoacrylate Coating Against Candida Albicans Biofilm Formation.}, journal = {Brazilian dental journal}, volume = {30}, number = {3}, pages = {266-271}, doi = {10.1590/0103-6440201901953}, pmid = {31166390}, issn = {1806-4760}, mesh = {Acrylic Resins ; Biofilms ; Brazil ; *Candida albicans ; Cyanoacrylates ; *Denture Bases ; Surface Properties ; }, abstract = {The aim of this study was to verify whether modifications made in a hard chairside reline resin by an ethyl-cyanoacrylate adhesive, ECA (Super Bonder®, Loctite, Itapevi, SP, Brazil) would be able to inhibit or reduce Candida albicans biofilm formation on its surface, comparing to a commercial surface sealant (BisCover®, Bisco, Schaumburg, USA). Reline resin specimens were fabricated and randomly divided into 6 groups (n=8): CG (control group), no surface treatment; ECA1, ECA coating on the surface before sterilization; ECA2, ECA coating after sterilization; ECA3, ECA incorporated in the resin bulk; DPE1, BisCover® coating before sterilization; DPE2, BisCover® coating after sterilization. Specimens were inoculated with C. albicans SC5314 (1x107 cells/mL) and incubated for 24 h. Then, the biofilm were stained with LIVE/DEAD® BaclightTM L7007 Kit and analyzed by Confocal Laser Scanning Microscopy. The images were evaluated by bioImageL® v.2.0 software and total biovolume (µm3), viable cells (%), and covered area (%) were calculated. Data were statistically analyzed by Kruskal-Wallis and Dunn tests (p<0.05). Results showed that ECA-coated groups presented better results, reducing C. albicans biofilm formation. Acquired images revealed that these groups (ECA1 and ECA2) presented a reduced number of cells, mostly in yeast form (less pathogenic), while the other groups presented higher number of cells, mostly in hyphae form (more pathogenic). Based on these findings, a beneficial effect of Super Bonder® coating reline resins surface could be demonstrated, suggesting a promising way to prevent fungal biofilm formation on dentures.}, } @article {pmid31166149, year = {2019}, author = {Iribarnegaray, V and Navarro, N and Robino, L and Zunino, P and Morales, J and Scavone, P}, title = {Magnesium-doped zinc oxide nanoparticles alter biofilm formation of Proteus mirabilis.}, journal = {Nanomedicine (London, England)}, volume = {14}, number = {12}, pages = {1551-1564}, doi = {10.2217/nnm-2018-0420}, pmid = {31166149}, issn = {1748-6963}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Magnesium/*chemistry ; Microscopy, Electron, Transmission ; Nanoparticles/*chemistry/ultrastructure ; Proteus mirabilis/*drug effects/*growth & development ; Zinc Oxide/*chemistry/pharmacology ; }, abstract = {Aim:Proteus mirabilis biofilms colonize medical devices, and their role in microbial pathogenesis is well established. Magnesium-doped zinc oxide nanoparticles (ZnO:MgO NPs) have potential antimicrobial properties; thus, we aimed at evaluating the antibiofilm activity of ZnO:MgO NPs against P. mirabilis biofilm. Materials & methods: After synthesis and characterization of ZnO:MgO NPs and their addition to a polymer film, we evaluated the stages of P. mirabilis biofilm development over glass coverslip covered by different concentrations of ZnO:MgO NPs. Results: Low concentrations of ZnO:MgO NPs affect the development of P. mirabilis biofilm. Descriptors showed reduced values in bacterial number, bacterial volume and extracellular material. Conclusion: Our results highlight this new application of ZnO:MgO NPs as a potential antibiofilm strategy in medical devices.}, } @article {pmid31165874, year = {2020}, author = {Turner, SD}, title = {Commentary on: Deposition of Host Matrix Proteins on Breast Implant Surfaces Facilitates Staphylococcus Epidermidis Biofilm Formation: In Vitro Analysis.}, journal = {Aesthetic surgery journal}, volume = {40}, number = {3}, pages = {296-298}, doi = {10.1093/asj/sjz144}, pmid = {31165874}, issn = {1527-330X}, mesh = {Biofilms ; *Breast Implantation ; *Breast Implants ; Staphylococcus epidermidis ; }, } @article {pmid31164053, year = {2019}, author = {Siebert, C and Lindgren, H and Ferré, S and Villers, C and Boisset, S and Perard, J and Sjöstedt, A and Maurin, M and Brochier-Armanet, C and Couté, Y and Renesto, P}, title = {Francisella tularensis: FupA mutation contributes to fluoroquinolone resistance by increasing vesicle secretion and biofilm formation.}, journal = {Emerging microbes & infections}, volume = {8}, number = {1}, pages = {808-822}, pmid = {31164053}, issn = {2222-1751}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms/drug effects ; Drug Resistance, Bacterial ; Extracellular Vesicles/genetics/*metabolism ; Fluoroquinolones/*pharmacology ; Francisella tularensis/*drug effects/*genetics/physiology ; Gene Deletion ; Microbial Sensitivity Tests ; Mutation ; }, abstract = {Francisella tularensis is the causative agent in tularemia for which the high prevalence of treatment failure and relapse is a major concern. Directed-evolution experiments revealed that acquisition of fluoroquinolone (FQ) resistance was linked to factors in addition to mutations in DNA gyrase. Here, using F. tularensis live vaccine strain (LVS) as a model, we demonstrated that FupA/B (Fer-Utilization Protein) expression is linked to FQ susceptibility, and that the virulent strain F. tularensis subsp. tularensis SCHU S4 deleted for the homologous FupA protein exhibited even higher FQ resistance. In addition to an increased FQ minimal inhibitory concentration, LVSΔfupA/B displayed tolerance toward bactericidal compounds including ciprofloxacin and gentamicin. Interestingly, the FupA/B deletion was found to promote increased secretion of outer membrane vesicles (OMVs). Mass spectrometry-based quantitative proteomic characterization of vesicles from LVS and LVS∆fupA/B identified 801 proteins, including a subset of 23 proteins exhibiting differential abundance between both strains which may therefore contribute to the reduced antibiotic susceptibility of the FupA/B-deleted strain. We also demonstrated that OMVs are key structural elements of LVSΔfupA/B biofilms providing protection against FQ. These results provide a new basis for understanding and tackling antibiotic resistance and/or persistence of Francisella and other pathogenic members of the Thiotrichales class.}, } @article {pmid31163253, year = {2019}, author = {Teh, AHT and Lee, SM and Dykes, GA}, title = {Growth in the presence of specific antibiotics induces biofilm formation by a Campylobacter jejuni strain sensitive to them but not in resistant strains.}, journal = {Journal of global antimicrobial resistance}, volume = {18}, number = {}, pages = {55-58}, doi = {10.1016/j.jgar.2019.05.020}, pmid = {31163253}, issn = {2213-7173}, mesh = {Animals ; Anti-Bacterial Agents/classification/*pharmacology ; Biofilms/drug effects/*growth & development ; Campylobacter jejuni/drug effects/isolation & purification/*physiology ; Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Poultry/microbiology ; }, abstract = {OBJECTIVE: Campylobacter jejuni (C. jejuni) are among the most frequently identified bacteria associated with human gastroenteritis worldwide. Exposure to antibiotics may induce or inhibit biofilm formation in some bacterial species. Little work has been reported on the influence of antibiotics on biofilm formation by C. jejuni.

METHODS: This study investigated the effect of six different classes of antibiotics with different modes of action (ampicillin, ciprofloxacin, erythromycin, nalidixic acid, rifampicin and tetracycline) on biofilm formation in vitro by seven C. jejuni from poultry with different antibiotic resistance profiles.

RESULTS: The results indicated that in the presence of most of the tested antibiotics, biofilm formation by C. jejuni strains, which are resistant to them, was reduced but biofilm formation in sensitive strains was increased.

CONCLUSION: The ability of certain antibiotics to induce biofilm formation by a tested C. jejuni strain is of concern, with respect to the effective control of disease caused by this pathogen; however, further work is required to confirm how widespread this feature is.}, } @article {pmid31163049, year = {2019}, author = {Maczynska, B and Secewicz, A and Smutnicka, D and Szymczyk, P and Dudek-Wicher, R and Junka, A and Bartoszewicz, M}, title = {In vitro efficacy of gentamicin released from collagen sponge in eradication of bacterial biofilm preformed on hydroxyapatite surface.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0217769}, pmid = {31163049}, issn = {1932-6203}, mesh = {Biofilms/*drug effects ; Collagen/*chemistry ; *Drug Liberation ; Durapatite/*chemistry ; Gentamicins/*pharmacology ; Klebsiella pneumoniae/*drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/ultrastructure ; Staphylococcus aureus/*drug effects ; Surface Properties ; }, abstract = {Biofilm-related infections of bones pose a significant therapeutic issue. In this article we present in vitro results of the efficacy of gentamicin released from a collagen sponge carrier against Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae biofilms preformed on hydroxyapatite surface. The results indicate that high local concentrations of gentamicin released from a sponge eradicate the biofilm formed not only by gentamicin-sensitive strains but, to some extent, also by those that display a resistance pattern in routine diagnostics. The data presented in this paper is of high clinical translational value and may find application in the treatment of bone infections.}, } @article {pmid31160079, year = {2019}, author = {Bukhari, S and Karabucak, B}, title = {The Antimicrobial Effect of Bioceramic Sealer on an 8-week Matured Enterococcus faecalis Biofilm Attached to Root Canal Dentinal Surface.}, journal = {Journal of endodontics}, volume = {45}, number = {8}, pages = {1047-1052}, doi = {10.1016/j.joen.2019.04.004}, pmid = {31160079}, issn = {1878-3554}, mesh = {*Anti-Bacterial Agents/therapeutic use ; Biofilms ; *Dental Pulp Cavity ; *Enterococcus faecalis ; Microscopy, Confocal ; *Pit and Fissure Sealants/therapeutic use ; *Root Canal Filling Materials ; Silicates ; }, abstract = {INTRODUCTION: The aim of this study was to test the antibacterial activity of bioceramic sealer in comparison with AH Plus (Dentsply International Inc, York, PA) on 8-week-old Enterococcus faecalis biofilms attached to root canal surfaces using a dentin infection model.

METHODS: The canal surfaces of single-rooted intact extracted teeth were infected by growing E. faecalis biofilms for 8 weeks. AH Plus sealer and EndoSequence BC Sealer (Brasseler USA, Savannah, GA) were placed on the root canal wall of the dentin specimens for 24 hours and 2 weeks in humid conditions at 37°C. Infected samples incubated with no sealers for similar periods were used as the negative controls. Specimens were labeled with fluorescent viability staining, and confocal laser scanning microscopy was used as an assessment tool of the proportions of dead and live bacteria on canal walls after exposure to root canal sealers for the determined times.

RESULTS: EndoSequence BC Sealer killed significantly more E. faecalis in biofilm attached to the canal surfaces when compared with AH plus sealer and control at both time points (P < .05-.0005).

CONCLUSIONS: EndoSequence BC Sealer exhibited significant antimicrobial capacity in the presence of dentin for up to 2 weeks on an 8-week-old E. faecalis biofilm in comparison with AH Plus sealer.}, } @article {pmid31158672, year = {2019}, author = {Pu, Y and Ngan, WY and Yao, Y and Habimana, O}, title = {Could benthic biofilm analyses be used as a reliable proxy for freshwater environmental health?.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {252}, number = {Pt A}, pages = {440-449}, doi = {10.1016/j.envpol.2019.05.111}, pmid = {31158672}, issn = {1873-6424}, mesh = {Biofilms/*drug effects/growth & development ; Ecosystem ; Environmental Health ; Environmental Monitoring/*methods ; Hong Kong ; Rivers/*chemistry ; Water Pollutants, Chemical/*analysis ; }, abstract = {The quality of freshwater undoubtedly reflects the health of our surrounding environment, society, and economy, as these are supported by various freshwater ecosystems. Monitoring efforts have therefore been considered a vital means of ensuring the ecological health of freshwater environments. Nevertheless, most aquatic environmental monitoring strategies largely focus on bulk water sampling for analysis of physicochemical and key biological indicators, which for the most part do not consider pollution events that occur at any time between sampling events. Because benthic biofilms are ubiquitous in aquatic environments, pollution released during sporadic events may be absorbed by these biofilms, which can act as repositories of pollutants. The aim of this study was to assess whether benthic biofilm monitoring could provide an efficient way of properly characterizing the extent of pollution in aquatic environments. Here, bulk water and benthic biofilms were sampled from three Hong Kong streams having various pollution profiles, and subsequently compared via high-resolution microscopy, metagenomic analysis, and analytical chemistry. The results indicated that biofilms were, indeed, reservoirs of environmental pollutants, having different profiles compared with that of the corresponding bulk water samples. Moreover, the results also suggested that biofilms sampled in polluted areas were characterized by a higher species richness. While the analytical testing of benthic biofilms still needs further development, the integration of chemical-pollutant profiles and biofilm sequencing data in future studies may provide unique perspectives for understanding and identifying pollution-related biofilm biomarkers.}, } @article {pmid31158320, year = {2019}, author = {Shin, DS and Eom, YB}, title = {Zerumbone inhibits Candida albicans biofilm formation and hyphal growth.}, journal = {Canadian journal of microbiology}, volume = {65}, number = {10}, pages = {713-721}, doi = {10.1139/cjm-2019-0155}, pmid = {31158320}, issn = {1480-3275}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Hyphae/*drug effects/growth & development ; Sesquiterpenes/*pharmacology ; }, abstract = {Candida albicans biofilm formation is considered an important matter because it can lead to strong resistance to conventional antifungal agents. Hyphae formed by C. albicans can also act as an important virulence factor related to its biofilm. The objective of this study was to determine the effect of zerumbone, a monocyclic sesquiterpene extracted from Zingiber zerumbet (L.) Smith, against C. albicans biofilm formation. Our results suggest that zerumbone possesses antifungal and antibiofilm activity that inhibits biofilm formation and eradicates preformed biofilm. Notably, zerumbone considerably reduced carbohydrate and DNA contents of biofilm matrix. In addition, zerumbone showed antivirulence effects by decreasing the growth of hyphae and inhibiting morphologic changes of C. albicans. Furthermore, zerumbone significantly downregulated expression levels of biofilm-related and hyphae-specific genes, including HWP1 and ALS3. Since zerumbone suppresses biofilm formation and hyphae growth, these results indicate that zerumbone could be used as a potential candidate to treat and prevent C. albicans biofilm-related infections.}, } @article {pmid31158231, year = {2019}, author = {Panmanee, W and Su, S and Schurr, MJ and Lau, GW and Zhu, X and Ren, Z and McDaniel, CT and Lu, LJ and Ohman, DE and Muruve, DA and Panos, RJ and Yu, HD and Thompson, TB and Tseng, BS and Hassett, DJ}, title = {The anti-sigma factor MucA of Pseudomonas aeruginosa: Dramatic differences of a mucA22 vs. a ΔmucA mutant in anaerobic acidified nitrite sensitivity of planktonic and biofilm bacteria in vitro and during chronic murine lung infection.}, journal = {PloS one}, volume = {14}, number = {6}, pages = {e0216401}, pmid = {31158231}, issn = {1932-6203}, support = {I01 BX000845/BX/BLRD VA/United States ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms/drug effects ; Chronic Disease ; Humans ; Hydrogen-Ion Concentration ; Lung/*microbiology ; *Mutation ; Nitrites/*pharmacology ; Plankton/metabolism/physiology ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/genetics/metabolism/*physiology ; }, abstract = {Mucoid mucA22 Pseudomonas aeruginosa (PA) is an opportunistic lung pathogen of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) patients that is highly sensitive to acidified nitrite (A-NO2-). In this study, we first screened PA mutant strains for sensitivity or resistance to 20 mM A-NO2- under anaerobic conditions that represent the chronic stages of the aforementioned diseases. Mutants found to be sensitive to A-NO2- included PA0964 (pmpR, PQS biosynthesis), PA4455 (probable ABC transporter permease), katA (major catalase, KatA) and rhlR (quorum sensing regulator). In contrast, mutants lacking PA0450 (a putative phosphate transporter) and PA1505 (moaA2) were A-NO2- resistant. However, we were puzzled when we discovered that mucA22 mutant bacteria, a frequently isolated mucA allele in CF and to a lesser extent COPD, were more sensitive to A-NO2- than a truncated ΔmucA deletion (Δ157-194) mutant in planktonic and biofilm culture, as well as during a chronic murine lung infection. Subsequent transcriptional profiling of anaerobic, A-NO2--treated bacteria revealed restoration of near wild-type transcript levels of protective NO2- and nitric oxide (NO) reductase (nirS and norCB, respectively) in the ΔmucA mutant in contrast to extremely low levels in the A-NO2--sensitive mucA22 mutant. Proteins that were S-nitrosylated by NO derived from A-NO2- reduction in the sensitive mucA22 strain were those involved in anaerobic respiration (NirQ, NirS), pyruvate fermentation (UspK), global gene regulation (Vfr), the TCA cycle (succinate dehydrogenase, SdhB) and several double mutants were even more sensitive to A-NO2-. Bioinformatic-based data point to future studies designed to elucidate potential cellular binding partners for MucA and MucA22. Given that A-NO2- is a potentially viable treatment strategy to combat PA and other infections, this study offers novel developments as to how clinicians might better treat problematic PA infections in COPD and CF airway diseases.}, } @article {pmid31157279, year = {2019}, author = {Lavery, LA and Bhavan, K and Wukich, DK}, title = {Biofilm and diabetic foot ulcer healing: all hat and no cattle.}, journal = {Annals of translational medicine}, volume = {7}, number = {7}, pages = {159}, pmid = {31157279}, issn = {2305-5839}, } @article {pmid31155952, year = {2019}, author = {Brilhante, RSN and Aguiar, L and Sales, JA and Araújo, GDS and Pereira, VS and Pereira-Neto, WA and Pinheiro, AQ and Paixão, GC and Cordeiro, RA and Sidrim, JJC and Bersano, PRO and Rocha, MFG and Castelo-Branco, DSCM}, title = {Ex vivo biofilm-forming ability of dermatophytes using dog and cat hair: an ethically viable approach for an infection model.}, journal = {Biofouling}, volume = {35}, number = {4}, pages = {392-400}, doi = {10.1080/08927014.2019.1599361}, pmid = {31155952}, issn = {1029-2454}, mesh = {Animals ; *Biofilms ; Cats ; *Dermatomycoses ; Dogs ; *Hair ; Hyphae ; Microscopy, Electron, Scanning ; Microsporum/*physiology ; Seasons ; Trichophyton/*physiology ; }, abstract = {The aim of this study was to establish an ex vivo model for dermatophyte biofilm growth, using hair from dogs and cats. Strains of Microsporum canis, M. gypseum, Trichophyton mentagrophytes and T. tonsurans were assessed for in vitro and ex vivo biofilm production. All T. mentagrophytes and T. tonsurans isolates and 8/12 M. canis and 1/7 M. gypseum isolates formed biofilms in vitro, while all tested isolates presented biofilm growth on ex vivo models. T. mentagrophytes and M. canis formed more homogeneous and better-structured biofilms with greater biomass production on cat hair but T. tonsurans formed more biofilm on dog hair. Confocal and scanning electron microscopy demonstrated fungal hyphae colonizing and perforating the hair shaft, abundant fungal conidia, biofilm extracellular matrix and biofilm water channels. The present study demonstrated an ex vivo model for the performance of studies on biofilm formation by dermatophytes, using dog and cat hair.}, } @article {pmid31155569, year = {2019}, author = {Ikezaki, S and Cho, T and Nagao, JI and Tasaki, S and Yamaguchi, M and Arita-Morioka, KI and Yasumatsu, K and Chibana, H and Ikebe, T and Tanaka, Y}, title = {Mild Heat Stress Affects on the Cell Wall Structure in Candida albicans Biofilm.}, journal = {Medical mycology journal}, volume = {60}, number = {2}, pages = {29-37}, doi = {10.3314/mmj.19-00001}, pmid = {31155569}, issn = {1882-0476}, mesh = {Antifungal Agents/pharmacology ; *Biofilms ; Candida albicans/*cytology/genetics/*physiology/ultrastructure ; Candidiasis/therapy ; Cell Wall/*pathology/ultrastructure ; Down-Regulation/genetics ; Drug Resistance, Fungal/genetics ; Fever/*microbiology ; Fungal Proteins/genetics/metabolism ; Gene Expression/genetics ; Gene Expression Regulation, Fungal/genetics ; *Hot Temperature ; Hyphae ; Membrane Glycoproteins/genetics/metabolism ; Micafungin/pharmacology ; Microscopy, Electron ; Stress, Physiological/*genetics/*physiology ; Time Factors ; }, abstract = {We previously reported that Candida albicans responded to mild heat stress in a range of temperature elevations simulating fever, and concluded that mild heat stress increases susceptibility to antifungal drugs. In this study, we show that mild heat stress causes a morphological change in hyphae during the process of biofilm formation. We found that mild heat stress extended the period of hyphal stage maintenance in C. albicans biofilm. Although the rate of hyphal change from yeast form to hyphal form reached the maximum within 3 hr, later, almost every cell quickly reverted to the yeast growth phase within 6 hr at 37°C but not at 39°C, or under mild heat stress. Electron microscopy using a smart specimen preparation technique revealed that mild heat stress significantly increased the thickness of the inner cell wall accompanied by a decrease in density of the outer cell wall in the hyphae of C. albicans biofilm. To identify the gene responsible for the morphological changes associated with mild heat stress, we performed microarray gene expression analysis. Eleven genes were upregulated and 17 genes were downregulated under mild heat stress in biofilm cells. The increased PHR1 gene expression in response to mild heat stress was confirmed in quantitative RT-PCR analysis. The mutant upregulated PHR1 expression showed the same sensitivity against antifungal drug micafungin as dependent on mild heat stress. Our findings point to possible therapeutic effects of hyperthermia as well as to the effect of fever during infections.}, } @article {pmid31152793, year = {2019}, author = {Albayaty, YN and Thomas, N and Jambhrunkar, M and Al-Hawwas, M and Kral, A and Thorn, CR and Prestidge, CA}, title = {Enzyme responsive copolymer micelles enhance the anti-biofilm efficacy of the antiseptic chlorhexidine.}, journal = {International journal of pharmaceutics}, volume = {566}, number = {}, pages = {329-341}, doi = {10.1016/j.ijpharm.2019.05.069}, pmid = {31152793}, issn = {1873-3476}, mesh = {Animals ; Anti-Infective Agents/*administration & dosage/toxicity ; Biofilms/drug effects ; Caenorhabditis elegans/drug effects ; Chlorhexidine/*administration & dosage/toxicity ; Ethylene Oxide/*administration & dosage/toxicity ; Lactones/*administration & dosage/toxicity ; *Micelles ; Polyethylene Glycols/*administration & dosage/toxicity ; Polyvinyls/*administration & dosage/toxicity ; Skin, Artificial/microbiology ; Staphylococcus aureus/*drug effects/physiology ; Staphylococcus epidermidis/*drug effects/physiology ; }, abstract = {Staphylococcal biofilms cause many infectious diseases and are highly tolerant to the effects of antimicrobials; this is partly due to the biofilm matrix, which acts as a physical barrier retarding the penetration and reducing susceptibility to antimicrobials, thereby decreasing successful treatment outcomes. In this study, both single and mixed micellar systems based on poly vinyl caprolactam (PCL)-polyethylene glycol (PEG) copolymers were optimised for delivery of chlorhexidine (CHX) to S. aureus, MRSA and S. epidermidis biofilms and evaluated for their toxicity using Caenorhabditis elegans. The respective polyethylene glycol (PEG) and poly vinyl caprolactam (PCL) structural components promoted stealth properties and enzymatic responsive release of CHX inside biofilms, leading to significantly enhanced penetration (56%) compared with free CHX and improving the efficacy against Staphylococcus aureus biofilms grown on an artificial dermis (2.4 log reduction of CFU). Mixing Soluplus-based micelles with Solutol further enhanced the CHX penetration (71%) and promoted maximum reduction in biofilm biomass (>60%). Nematodes-based toxicity assay showed micelles with no lethal effects as indicated by their high survival rate (100%) after 72 h exposure. This study thus demonstrated that bio-responsive carriers can be designed to deliver a poorly water-soluble antimicrobial agent and advance the control of biofilm associated infections.}, } @article {pmid31152205, year = {2019}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Biofilm reactors as a promising method for vitamin K (menaquinone-7) production.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {14}, pages = {5583-5592}, doi = {10.1007/s00253-019-09913-w}, pmid = {31152205}, issn = {1432-0614}, support = {Project PEN04561 and Accession number 1002249//USDA National Institute of Food and Agriculture Federal Appropriations/ ; }, mesh = {Bacillus subtilis/*metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Culture Media/chemistry ; Fermentation ; Glucose/metabolism ; Humans ; Vitamin K 2/*analogs & derivatives/metabolism ; }, abstract = {Menaquinone-7 (MK-7) is the most potent subtype of vitamin K with extraordinarily high half-life in the circulatory system. Therefore, MK-7 plays a critical role in promoting human wellbeing today. Studies on MK-7 every year show more and more magnificent benefits of it in preventing cardiovascular diseases and osteoporosis to battling cancer cells, Alzheimer's and Parkinson's diseases. Thus, it needs to be supplemented to daily diet for accumulative and long-term benefits. Chemical synthesis of MK-7 produces a significant cis-isomer form of it, which has no biological activity. Fortunately, due to its key role in electron transfer in bacteria, trans-MK-7 is biosynthesized by especially Gram-positive strains mainly Bacillus genus. Concordantly, MK-7 could be produced via solid or liquid state fermentation strategies. In either regime, when static fermentation is applied in the absence of agitation and aeration, operational issues arise such as heat and mass transfer inefficiencies. Thus, scaling up the process becomes a challenge. On the other hand, studies have indicated that biofilm and pellicle formation that occur in static fermentations are key characteristics for extracellular MK-7 secretion. Therefore, this review covers the most recent discoveries of the therapeutic properties of MK-7 and optimization attempts at increasing its biosynthesis in different media compositions and effective growth parameters as well as the cutting-edge use of biofilm reactors where B. subtilis cells have the infrastructures to form mature biofilm formations on plastic composite supports. Biofilm reactors therefore can provide robust extracellular MK-7 secretion while simultaneously enduring high agitation and aeration rates, which then address the scale-up and operational issues associated with static fermentation strategies.}, } @article {pmid31151296, year = {2019}, author = {Picco, DCR and Marangoni-Lopes, L and Parisotto, TM and Mattos-Graner, R and Nobre-Dos-Santos, M}, title = {Activity of Carbonic Anhydrase VI is Higher in Dental Biofilm of Children with Caries.}, journal = {International journal of molecular sciences}, volume = {20}, number = {11}, pages = {}, pmid = {31151296}, issn = {1422-0067}, support = {2012/02886-3 and 2012/15834-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 1289/2006//Fundo de Apoio ao Ensino, à Pesquisa e Extensão, Universidade Estadual de Campinas/ ; }, mesh = {*Biofilms ; Carbonic Anhydrases/*metabolism ; Child ; Dental Caries/*enzymology/microbiology/*pathology ; Dental Plaque/*microbiology ; Enzyme Activation ; Female ; Humans ; Hydrogen-Ion Concentration ; Male ; }, abstract = {This study investigated pH, activity and concentration of carbonic anhydrase VI (CA VI) in dental biofilm of caries and caries-free children of 7-9 years old. Seventy-four children were selected and divided into two groups. The caries diagnosis was performed according to the WHO criteria, including the early caries lesion. After biofilm collection and pH determination, CA VI concentration and activity were determined by ELISA and Zimography respectively. The data were submitted to a Mann-Whitney test and to Pearson and Spearman correlation analyses. Means and standard deviations of dental caries for the caries group were of 3.162 ± 1.385. The biofilm pH was significantly higher in the caries-free group. The CA VI activity was significantly higher in biofilm of children with caries. The CA VI concentration was significantly higher in biofilm of caries-free children. In caries-free children, there was a moderate negative correlation between CA VI activity and concentration in dental biofilm as well as between pH and CA VI activity. A negative correlation between biofilm pH and CA VI concentration was found in the caries group. In conclusion, CA VI was shown to be more active in the biofilm of school children with caries in order to contribute to neutralization of biofilm acid.}, } @article {pmid31151290, year = {2019}, author = {Simonetti, G and Palocci, C and Valletta, A and Kolesova, O and Chronopoulou, L and Donati, L and Di Nitto, A and Brasili, E and Tomai, P and Gentili, A and Pasqua, G}, title = {Anti-Candida Biofilm Activity of Pterostilbene or Crude Extract from Non-Fermented Grape Pomace Entrapped in Biopolymeric Nanoparticles.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {11}, pages = {}, pmid = {31151290}, issn = {1420-3049}, support = {C26A14RP98//University Sapienza of Rome/ ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Biopolymers/chemistry ; Candida/*drug effects ; Chemical Phenomena ; *Nanoparticles/chemistry ; Plant Extracts/chemistry/*pharmacology ; Polylactic Acid-Polyglycolic Acid Copolymer/chemistry ; Stilbenes/chemistry/*pharmacology ; Vitis/chemistry ; }, abstract = {Polymeric nanoparticle-based carriers are promising agents to deliver drugs to cells. Vitis vinifera phenolic compounds are known for their antifungal activity against Candida albicans. The aim of the present study was to investigate the antifungal activity of pterostilbene or crude extracts from non-fermented grape pomace, entrapped in poly(lactic-co-glycolic) acid nanoparticles (NPs), with diameters of 50 and 150 nm, on Candida biofilm. The fluorescent probe coumarin 6 was used to study the uptake of poly(lactic-co-glycolic)acid (PLGA) NPs in planktonic cells and biofilm. The green fluorescent signal of coumarin 6 was observed in Candida biofilm after 24 and 48 hours. Both pterostilbene and crude pomace extract entrapped in NPs exerted a significantly higher anti-biofilm activity compared to their free forms. The entrapment efficiency of both pterostilbene and crude pomace extract in PLGA NPs was ~90%. At 16 µg/mL, pterostilbene loaded in PLGA NPs reduced biofilm formation of 63% and reduced mature biofilm of 50%. Moreover, at 50 µg/mL, the pomace extract loaded in NPs reduced mature biofilm of 37%. These results strongly suggest that PLGA NPs are promising nanodevices for the delivery of antifungal drugs as the crude grape pomace extract, a by-product of white wine making.}, } @article {pmid31151195, year = {2019}, author = {Heersema, LA and Smyth, HDC}, title = {A Multispecies Biofilm In Vitro Screening Model of Dental Caries for High-Throughput Susceptibility Testing.}, journal = {High-throughput}, volume = {8}, number = {2}, pages = {}, pmid = {31151195}, issn = {2571-5135}, support = {DGE-1610403//National Science Foundation/ ; }, abstract = {There is a current need to develop and optimize new therapeutics for the treatment of dental caries, but these efforts are limited by the relatively low throughput of relevant in vitro models. The aim of this work was to bridge the 96-well microtiter plate system with a relevant multispecies dental caries model that could be reproducibly grown to allow for the high-throughput screening of anti-biofilm therapies. Various media and inoculum concentrations were assessed using metabolic activity, biomass, viability, and acidity assays to determine the optimal laboratory-controlled conditions for a multispecies biofilm composed of Streptococcus gordonii, Streptococcus mutans, and Candida albicans. The selected model encompasses several of the known fundamental characteristics of dental caries-associated biofilms. The 1:1 RPMI:TSBYE 0.6% media supported the viability and biomass production of mono- and multispecies biofilms best. Kinetic studies over 48 h in 1:1 RPMI:TSBYE 0.6% demonstrated a stable biofilm phase between 10 and 48 h for all mono- and multispecies biofilms. The 1:1:0.1 S. gordonii: S. mutans: C. albicans multispecies biofilm in 1:1 RPMI:TSBYE 0.6% is an excellent choice for a high-throughput multispecies model of dental caries. This high-throughput multispecies model can be used for screening novel therapies and for better understanding the treatment effects on biofilm interactions and stability.}, } @article {pmid31151056, year = {2019}, author = {Rajivgandhi, G and Maruthupandy, M and Muneeswaran, T and Anand, M and Quero, F and Manoharan, N and Li, WJ}, title = {Biosynthesized silver nanoparticles for inhibition of antibacterial resistance and biofilm formation of methicillin-resistant coagulase negative Staphylococci.}, journal = {Bioorganic chemistry}, volume = {89}, number = {}, pages = {103008}, doi = {10.1016/j.bioorg.2019.103008}, pmid = {31151056}, issn = {1090-2120}, mesh = {Actinobacteria/chemistry/metabolism ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; Metal Nanoparticles/*chemistry ; Methicillin/chemistry/*pharmacology ; Methicillin Resistance/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Silver/chemistry/metabolism/*pharmacology ; Staphylococcus/*drug effects ; Structure-Activity Relationship ; }, abstract = {The ability of a natural stabilizing and reducing agent on the synthesis of silver nanoparticles (Ag NPs) was explored using a rapid and single-pot biological reduction method using Nocardiopsis sp. GRG1 (KT235640) biomass. The UV-visible spectral analysis of Ag NPs was found to show a maximum absorption peak located at a wavelength position of ∼422 nm for initial conformation. The major peaks in the XRD pattern were found to be in excellent agreement with the standard values of metallic Ag NPs. No other peaks of impurity phases were observed. The morphology of Ag NPs was confirmed through TEM observation, demonstrating that the particle size distribution of Ag NPs entrenched in spherical particles is in a range between 20 and 50 nm. AFM analysis further supported the nanosized morphology of the synthesized Ag NPs and allowed quantifying the Ag NPs surface roughness. The synthesized Ag NPs showed significant antibacterial and antibiofilm activity against biofilm positive methicillin-resistant coagulase negative Staphylococci (MR-CoNS), which were isolated from urinary tract infection as determined by spectroscopic methods in the concentration range of 5-60 µg/ml. The inhibition of biofilm formation with coloring stain was morphologically imaged by confocal laser scanning microscopy (CLSM). Morphological alteration of treated bacteria was observed by SEM analysis. The results clearly indicate that these biologically synthesized Ag NPs could provide a safer alternative to conventional antibiofilm agents against uropathogen of MR-CoNS.}, } @article {pmid31149345, year = {2019}, author = {Tahrioui, A and Duchesne, R and Bouffartigues, E and Rodrigues, S and Maillot, O and Tortuel, D and Hardouin, J and Taupin, L and Groleau, MC and Dufour, A and Déziel, E and Brenner-Weiss, G and Feuilloley, M and Orange, N and Lesouhaitier, O and Cornelis, P and Chevalier, S}, title = {Extracellular DNA release, quorum sensing, and PrrF1/F2 small RNAs are key players in Pseudomonas aeruginosa tobramycin-enhanced biofilm formation.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {15}, pmid = {31149345}, issn = {2055-5008}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; DNA, Bacterial/*metabolism ; Gene Expression Profiling ; Microscopy, Confocal ; Proteomics ; Pseudomonas aeruginosa/*drug effects/enzymology/growth & development ; *Quorum Sensing ; RNA, Small Untranslated/*metabolism ; Stress, Physiological ; Tobramycin/*pharmacology ; }, abstract = {Biofilms are structured microbial communities that are the leading cause of numerous chronic infections which are difficult to eradicate. Within the lungs of individuals with cystic fibrosis (CF), Pseudomonas aeruginosa causes persistent biofilm infection that is commonly treated with aminoglycoside antibiotics such as tobramycin. However, sublethal concentrations of this aminoglycoside were previously shown to increase biofilm formation by P. aeruginosa, but the underlying adaptive mechanisms still remain elusive. Herein, we combined confocal laser scanning microscope analyses, proteomics profiling, gene expression assays and phenotypic studies to unravel P. aeruginosa potential adaptive mechanisms in response to tobramycin exposure during biofilm growth. Under this condition, we show that the modified biofilm architecture is related at least in part to increased extracellular DNA (eDNA) release, most likely as a result of biofilm cell death. Furthermore, the activity of quorum sensing (QS) systems was increased, leading to higher production of QS signaling molecules. We also demonstrate upon tobramycin exposure an increase in expression of the PrrF small regulatory RNAs, as well as expression of iron uptake systems. Remarkably, biofilm biovolumes and eDNA relative abundances in pqs and prrF mutant strains decrease in the presence of tobramycin. Overall, our findings offer experimental evidences for a potential adaptive mechanism linking PrrF sRNAs, QS signaling, biofilm cell death, eDNA release, and tobramycin-enhanced biofilm formation in P. aeruginosa. These specific adaptive mechanisms should be considered to improve treatment strategies against P. aeruginosa biofilm establishment in CF patients' lungs.}, } @article {pmid31148964, year = {2019}, author = {Abbas, HA and Elsherbini, AM and Shaldam, MA}, title = {Glyceryl trinitrate blocks staphyloxanthin and biofilm formation in Staphylococcus aureus.}, journal = {African health sciences}, volume = {19}, number = {1}, pages = {1376-1384}, pmid = {31148964}, issn = {1729-0503}, mesh = {Biofilms/*drug effects ; Drug Resistance, Microbial ; Humans ; Molecular Docking Simulation ; Nitroglycerin/*pharmacology ; Oxidative Stress/drug effects ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/pathogenicity ; Virulence/drug effects ; Virulence Factors ; Xanthophylls/*biosynthesis ; }, abstract = {BACKGROUND: Staphylococcus aureus is an important nosocomial bacterium that is responsible for a number of infections that may be fatal. The treatment of such infections is limited by emergence of antibiotic resistance. Targeting virulence of Staphylococcus aureus may provide an alternative option to antibiotic that may bypass the emergence of resistant strains due to lack of stress on viability.

OBJECTIVES: Investigation of the ability of glyceryl trinitrate (GTN) to inhibit staphyloxanthin, biofilm and tolerance to oxidative stress.

METHODS: The disk sensitivity method was used to detect the methicillin resistance of Staphylococcus aureus. The effect of sub-inhibitory concentration of GTN on biofilm formation, staphyloxanthin production and tolerance to oxidative stress was evaluated. Molecular docking study was used to investigate the ability of GTN to bind to dehydrosqualene synthase enzyme.

RESULTS: GTN showed a significant inhibition of biofilm, staphyloxanthin and tolerance to oxidative stress. In the molecular docking study, it was found that GTN could bind to dehydrosqualene synthase enzyme by hydrogen bonding, electrostatic interaction and pi-cation interaction.

CONCLUSION: The present study revealed the ability of GTN to serve as a potential anti-virulence candidate for attenuation of S. aureus pathogenicity.}, } @article {pmid31147809, year = {2019}, author = {Song, H and Zhang, J and Qu, J and Liu, J and Yin, P and Zhang, G and Shang, D}, title = {Lactobacillus rhamnosus GG microcapsules inhibit Escherichia coli biofilm formation in coculture.}, journal = {Biotechnology letters}, volume = {41}, number = {8-9}, pages = {1007-1014}, doi = {10.1007/s10529-019-02694-2}, pmid = {31147809}, issn = {1573-6776}, support = {81601734//National Natural Science Foundation of China/ ; }, mesh = {*Antibiosis ; Biofilms/*growth & development ; Capsules ; Coculture Techniques ; Escherichia coli/*growth & development ; Lacticaseibacillus rhamnosus/*growth & development ; }, abstract = {OBJECTIVES: Microbial biofilms have become one of the most significant causes of nosocomial infections. The aim of this study was to examine the potential quorum sensing inhibitor activities of Lactobacillus rhamnosus GG microcapsules.

RESULTS: Lactobacillus rhamnosus GG microcapsules effectively inhibited initial biofilm formation at a concentration of 2.5 × 10[8] CFU/mL. Furthermore, the inhibition rate was increased to 79% in the Lactobacillus rhamnosus GG microcapsules group, resulting in a reduction in the biofilm maturation stage. In addition, real-time PCR analysis revealed that the LGG microcapsules can act as effective inhibitors of transcriptional activators of the quorum sensing circuit in E.coli, luxS, lsrK, and lsrR.

CONCLUSIONS: Lactobacillus rhamnosus GG microcapsules can effectively inhibit biofilm formation and disturb mature biofilms.}, } @article {pmid31147580, year = {2019}, author = {Tanaka, N and Kogo, T and Hirai, N and Ogawa, A and Kanematsu, H and Takahara, J and Awazu, A and Fujita, N and Haruzono, Y and Ichida, S and Tanaka, Y}, title = {In-situ detection based on the biofilm hydrophilicity for environmental biofilm formation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {8070}, pmid = {31147580}, issn = {2045-2322}, mesh = {*Biofilms ; Biofouling/*prevention & control ; Coloring Agents/chemistry ; Extracellular Polymeric Substance Matrix/*chemistry ; Gentian Violet/chemistry ; Hydrophobic and Hydrophilic Interactions ; Materials Science/instrumentation/*methods ; Microbiological Techniques/instrumentation/methods ; Staining and Labeling/methods ; Surface Properties ; Water/chemistry ; Wettability ; }, abstract = {A biofilm has a unique structure composed of microorganisms, extracellular polymeric substances (EPSs), etc., and it is layered on a substrate in water. In material science, it is important to detect the biofilm formed on a surface to prevent biofouling. EPSs, the major component of the biofilm, mainly consist of polysaccharides, proteins, nucleic acids, and lipids. Because these biomolecules have a variety of hydrophilicities or hydrophobicities, the substrate covered with the biofilm shows different wettability from the initial state. To detect the biofilm formation, this study employed a liquid-squeezing-based wettability assessment method with a simple wettability index: the liquid-squeezed diameter of a smaller value indicates higher wettability. The method is based on the liquid-squeezing behaviour of a liquid that covers sample surfaces when an air-jet is applied. To form the biofilm, polystyrene surfaces were immersed and incubated in a water-circulated bioreactor that had collected microorganisms in ambient air. After the 14-d incubation, good formation of the biofilm on the surfaces was confirmed by staining with crystal violet. Although the contact angles of captive bubbles on the surfaces with the biofilm were unmeasurable, the liquid-squeezing method could distinguish between hydrophilic and hydrophobic initial surfaces with and without biofilm formation using the diameter of the liquid-squeezed area. The surface wettability is expected to be a promising property for in-situ detection of biofilm formation on a macroscopic scale.}, } @article {pmid31146243, year = {2019}, author = {Gong, M and Yang, G and Zhuang, L and Zeng, EY}, title = {Microbial biofilm formation and community structure on low-density polyethylene microparticles in lake water microcosms.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {252}, number = {Pt A}, pages = {94-102}, doi = {10.1016/j.envpol.2019.05.090}, pmid = {31146243}, issn = {1873-6424}, mesh = {Bacteroidetes/classification/genetics/*growth & development ; Biofilms/growth & development ; Ecosystem ; Firmicutes/classification/genetics/*growth & development ; Hydrophobic and Hydrophilic Interactions ; Lakes/microbiology ; Nanoparticles/*microbiology ; Polyethylene/*chemistry ; Proteobacteria/classification/genetics/*growth & development ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The occurrence of microplastics (MPs) in the environment has been gaining widespread attention globally. MP-colonizing microorganisms are important links for MPs contamination in various ecosystems, but have not been well understood. To partially address this issue, the present study investigated biofilm formation by microorganisms originating from lake water on low-density polyethylene (LDPE) MPs using a cultivation approach and the surface-related effects on the MP-associated microbial communities using 16S rRNA high-throughput sequencing. With the addition of nonionic surfactants and UV-irradiation pretreatment that changed the surface properties of LDPE MPs, more microorganisms were colonized on LDPE surface. Microbial community analysis indicated that LDPE MPs were primarily colonized by the phyla Proteobacteria, Bacteroidetes and Firmicutes, and the surface roughness and hydrophobicity of MP were important factors shaping the LDPE MP-associated microbial community structure. Half of the top 20 most abundant genera colonizing on LDPE were found to be potential pathogens, e.g., plant pathogens Agrobacterium, nosocomial pathogens Chryseobacterium and fish pathogens Flavobacterium. This study demonstrated rapid bacterial colonization of LDPE MPs in lake water microcosms, the role of MPs as transfer vectors for harmful microorganisms in lake water, and provided a first glimpse into the effect of surface properties on LDPE MP-associated biofilm communities.}, } @article {pmid31146189, year = {2019}, author = {Li, J and Peng, Y and Zhang, L and Liu, J and Wang, X and Gao, R and Pang, L and Zhou, Y}, title = {Quantify the contribution of anammox for enhanced nitrogen removal through metagenomic analysis and mass balance in an anoxic moving bed biofilm reactor.}, journal = {Water research}, volume = {160}, number = {}, pages = {178-187}, doi = {10.1016/j.watres.2019.05.070}, pmid = {31146189}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; *Denitrification ; *Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; Sewage ; }, abstract = {In this study, enhanced nitrogen removal through in situ enrichment of anammox bacteria was successfully obtained in a full-scale municipal wastewater treatment plant (WWTP). The WWTP was an anaerobic-anoxic-oxic (AAO) process and upgraded by adding moving carriers into the anoxic zone. Enhanced nitrogen removal was obtained during almost two years of operation. The significant nitrogen removal might be associated with the in situ enrichment of anammox bacteria on the adding carriers, as revealed by the comprehensive results of molecular analysis and [15]N-stable isotope tracing tests. Quantitative PCR results indicated that anammox bacteria in the anoxic-carrier biofilms presented a higher abundance than flocculent sludge (16S rRNA: P < 0.005; HzsB: P < 0.042). The 16S rRNA amplicon sequencing showed significant differences in the phylum Planctomycetes (P < 0.001) between anoxic-carrier biofilms and flocculent sludge. And metagenomic sequencing analysis further revealed the anammox relative abundance in the anoxic-carrier biofilms was significantly higher than the reported level in the flocculent sludge of conventional WWTPs. In addition, [15]N-stable isotope tracing tests showed that anammox could be combined with nitrate reduction by the anoxic-carrier biofilms. Thus, enriched anammox bacteria might contribute to nitrogen loss and lead to improvements in the nitrogen removal, which was also supported by the mass balance analysis of organic carbon, nitrogen, and phosphorus of the WWTP. Overall, this study suggests that anoxic-carrier biofilms might be a candidate to enhance nitrogen removal through partial anammox in municipal WWTPs.}, } @article {pmid31146064, year = {2019}, author = {Richard, H and Carpenter, EJ and Komada, T and Palmer, PT and Rochman, CM}, title = {Biofilm facilitates metal accumulation onto microplastics in estuarine waters.}, journal = {The Science of the total environment}, volume = {683}, number = {}, pages = {600-608}, doi = {10.1016/j.scitotenv.2019.04.331}, pmid = {31146064}, issn = {1879-1026}, mesh = {*Biofilms ; *Environmental Monitoring ; *Estuaries ; Metals/*chemistry ; Plastics/*chemistry ; Polyethylene ; Waste Products ; Water Pollutants, Chemical/analysis/*chemistry ; }, abstract = {In aquatic environments, plastic debris accumulates chemical pollutants from the surrounding water, potentially altering the fate of xenobiotics in these ecosystems. The effects of biofouling on the potential for plastic to sorb environmental pollutants remain poorly understood. In this study, we test the hypothesis that concentrations of metals are directly related to biofilm accumulation on microplastics submerged in natural estuarine waters. Two types of pre-production plastic pellets (polylactic acid (PLA) and low-density polyethylene (LDPE)) and glass pellets, were suspended for up to 28 days in an urbanized estuary (San Francisco Bay, California) to investigate how biofilm affects the accumulation of metals on these materials. During the initial weeks of the experiment, biofilm growth differed between locations, but after 28 days, PLA and LDPE had similar amounts of biofilm at the two field sites. Biofilm was the only significant predictor variable for Ba, Cs, Fe, Ga, Ni and Rb, and simple regressions of these metals after one month of submersion predicted much of the variability in the data (respective adjusted R[2] values: 0.46, 0.90, 0.86, 0.81, 0.87, 0.90; p < 0.001). For other metals influenced by location or substrate material, multivariate analysis showed that increases in metal concentrations were predicted by increases in biofilm for Cu, Pb, Al, K, U, Co, Mg (p < 0.001) and Mn (p < 0.01). This work highlights the role of biofilm in facilitating metal accumulation on plastic debris and contributes to current understanding of the underlying processes that influence the behavior of microplastics as aquatic contaminants.}, } @article {pmid31145677, year = {2019}, author = {Abriat, C and Virgilio, N and Heuzey, MC and Daigle, F}, title = {Microbiological and real-time mechanical analysis of Bacillus licheniformis and Pseudomonas fluorescens dual-species biofilm.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {7}, pages = {747-756}, doi = {10.1099/mic.0.000819}, pmid = {31145677}, issn = {1465-2080}, mesh = {Bacillus licheniformis/chemistry/genetics/growth & development/*physiology ; *Biofilms ; Kinetics ; Pseudomonas fluorescens/chemistry/genetics/growth & development/*physiology ; Staining and Labeling ; }, abstract = {In natural habitats, bacterial species often coexist in biofilms. They interact in synergetic or antagonistic ways and their interactions can influence the biofilm development and properties. Still, very little is known about how the coexistence of multiple organisms impact the multispecies biofilm properties. In this study, we examined the behaviour of a dual-species biofilm at the air-liquid interface composed by two environmental bacteria: Bacillus licheniformis and a phenazine mutant of Pseudomonas fluorescens. Study of the planktonic and biofilm growths for each species revealed that P. fluorescens grew faster than B. licheniformis and no bactericidal effect from P. fluorescens was detected, suggesting that the growth kinetics could be the main factor in the dual-species biofilm composition. To validate this hypothesis, the single- and dual-species biofilm were characterized by biomass quantification, microscopy and rheology. Bacterial counts and microscale architecture analysis showed that both bacterial populations coexist in the mature pellicle, with a dominance of P. fluorescens. Real-time measurement of the dual-species biofilms' viscoelastic (i.e. mechanical) properties using interfacial rheology confirmed that P. fluorescens was the main contributor of the biofilm properties. Evaluation of the dual-species pellicle viscoelasticity at longer time revealed that the biofilm, after reaching a first equilibrium, created a stronger and more cohesive network. Interfacial rheology proves to be a unique quantitative technique, which combined with microscale imaging, contributes to the understanding of the time-dependent properties within a polymicrobial community at various stages of biofilm development. This work demonstrates the importance of growth kinetics in the bacteria competition for the interface in a model dual-species biofilm.}, } @article {pmid31145519, year = {2019}, author = {Mori, Y and Nakagami, G and Kitamura, A and Minematsu, T and Kinoshita, M and Suga, H and Kurita, M and Hayashi, C and Kawasaki, A and Sanada, H}, title = {Effectiveness of biofilm-based wound care system on wound healing in chronic wounds.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {27}, number = {5}, pages = {540-547}, doi = {10.1111/wrr.12738}, pmid = {31145519}, issn = {1524-475X}, mesh = {Aged ; Aged, 80 and over ; Anti-Infective Agents, Local ; Biofilms ; Cross-Sectional Studies ; Debridement/instrumentation/*methods ; Female ; Humans ; Male ; Middle Aged ; Necrosis/microbiology/*therapy ; Point-of-Care Systems ; Pressure Ulcer/microbiology/*therapy ; Treatment Outcome ; Wound Healing/*physiology ; Wound Infection/microbiology/*therapy ; }, abstract = {A biofilm plays a crucial role in delaying wound healing. Sharp debridement, a possible effective method for eliminating biofilms, can only be applied to the wound with visible necrotic tissue; thus, no option has been available for eliminating biofilms that are not accompanied by necrotic tissue. Wound blotting was recently developed to visualize biofilm noninvasively and quickly, and ultrasonic debridement is available for biofilm removal. Therefore, the purpose of this study was to investigate the efficacy of "biofilm-based wound care system (BWCS)," a combination of wound blotting as a point-of-care testing and ultrasonic debridement, for promoting wound healing. Firstly, the cross-sectional study was conducted to examine the proportion of biofilm removal by ultrasonic debridement in pressure ulcers [Study 1]. Subsequently, the retrospective cohort study was conducted to examine the effectiveness of BWCS for healing of chronic wounds [Study 2]. The proportions of wound healing between wounds treated with BWCS and those with standard care in the home-visiting clinic were compared by Kaplan-Meier curve, and the Cox proportional hazard modeling was used to assess the effect of BWCS on wound healing. In Study 1, the median of biofilm removal proportion was 38.9% (interquartile range, 12.9-68.0%) for pressure ulcers treated with standard care and 65.2% (41.1-78.8%) for those treated with ultrasonic debridement (p = 0.009). In Study 2, the proportion of wound healing within 90 days was significantly higher in wounds treated with BWCS than in those treated with standard care (p = 0.001). The adjusted hazard ratio of BWCS for wound healing was 4.5 (95% confidence interval, 1.3-15.0; p = 0.015). In conclusion, we demonstrated that our novel approach, BWCS, can be a promising therapeutic strategy for visualizing biofilms that are not accompanied by necrotic tissue and promoting healing in chronic wounds.}, } @article {pmid31145040, year = {2021}, author = {Rizk, N and Ait-Mouheb, N and Molle, B and Roche, N}, title = {Treated wastewater reuse in micro-irrigation: effect of shear stress on biofilm development kinetics and chemical precipitation.}, journal = {Environmental technology}, volume = {42}, number = {2}, pages = {206-216}, doi = {10.1080/09593330.2019.1625956}, pmid = {31145040}, issn = {1479-487X}, mesh = {*Agricultural Irrigation ; Biofilms ; Chemical Precipitation ; Kinetics ; *Wastewater ; }, abstract = {Treated wastewater in micro-irrigation is a promising approach that could be used to decrease the pressure on good quality water resources. However, the clogging of such systems due to biofilm development and chemical precipitation constitute a constraint with the use of treated wastewater (TWW) and lead to lower irrigation system performance. The objective of this work is to study the development of biofilm and composition of fouling due to TWW under shear stresses of 0.7, 2.2 and 4.4 Pa detected along micro-irrigation systems. For this purpose, a Taylor-Couette reactor (TCR) was specifically calibrated for the cultivation of biofilm. The analysis of fouling composition samples (organic and inorganic) shows that biofilm tends to develop under the highest shear stress value (4.4 Pa). Precipitation of calcium carbonate in the form of calcite was observed in conjunction with biofilm growth using X-ray diffractometry (XRD) and thermogravimetric analysis (TGA). These results can be used to ascertain the origins of chemical and biological clogging of drippers and fouling of pipes related to reclaimed water- irrigation.}, } @article {pmid31144524, year = {2019}, author = {Rasmussen, RM and Epperson, RT and Taylor, NB and Williams, DL}, title = {Plume height and surface coverage analysis of methicillin-resistant Staphylococcus aureus isolates grown in a CDC biofilm reactor.}, journal = {Biofouling}, volume = {35}, number = {4}, pages = {463-471}, doi = {10.1080/08927014.2019.1612381}, pmid = {31144524}, issn = {1029-2454}, mesh = {*Biofilms ; Bioreactors ; Caseins ; Culture Media ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Protein Hydrolysates ; }, abstract = {Biofilm formation is a dynamic process that leads to mature communities over time. Despite a general knowledge of biofilm community formation and the resultant limitations of antibiotic therapy, there is a paucity of data describing specific plume heights, surface coverage and rates of maturation. Furthermore, little is published on the effect that the broth medium might have on the degree of biofilm maturation. In this study, three strains of methicillin-resistant Staphylococcus aureus (MRSA) (USA300, USA400 and a clinical isolate) were grown in brain heart infusion broth (BHI) or tryptic soy broth (TSB). Following growth, SEM images were captured for 3-D analysis to assess plume height. TSB produced significantly higher plume heights of USA300 and USA400 compared to BHI. Broth type was less influential on the clinical isolate. The data indicate that broth type and time may be important factors to consider when assessing maturation and plume height formation of MRSA biofilms.}, } @article {pmid31144441, year = {2019}, author = {Casciaro, B and Lin, Q and Afonin, S and Loffredo, MR and de Turris, V and Middel, V and Ulrich, AS and Di, YP and Mangoni, ML}, title = {Inhibition of Pseudomonas aeruginosa biofilm formation and expression of virulence genes by selective epimerization in the peptide Esculentin-1a(1-21)NH2.}, journal = {The FEBS journal}, volume = {286}, number = {19}, pages = {3874-3891}, pmid = {31144441}, issn = {1742-4658}, support = {R01 AI133351/AI/NIAID NIH HHS/United States ; INST 12384/58-1 FUGG//Deutsche Forschungsgemeinschaft/International ; AI-133351//National Institutes of Health awards/International ; //Italian Cystic Fibrosis Foundation (project FFC#11/2014 adopted by FFC Delegations from Siena, Sondrio Valchiavenna, Cerea Il Sorriso di Jenny, and Pavia and project FFC 15/2017 Adopted by Delegations of Palermo, Vittoria, Ragusa, Siracusa, Catania Mascalucia, Messina, Gruppo di Sostegno di Tremestieri)/International ; RM11816436113D8A//Sapienza University of Rome/International ; RM116154C8434109//Sapienza University of Rome/International ; R01 HL091938/HL/NHLBI NIH HHS/United States ; R01 HL125128/HL/NHLBI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; *Genes, Bacterial ; Glycosides/chemistry/*pharmacology ; Isomerism ; Pregnenolone/*analogs & derivatives/chemistry/pharmacology ; Pseudomonas aeruginosa/genetics/*metabolism/pathogenicity ; Virulence/*genetics ; }, abstract = {Pseudomonas aeruginosa is a pathogenic bacterium known to cause serious human infections, especially in immune-compromised patients. This is due to its unique ability to transform from a drug-tolerant planktonic to a more dangerous and treatment-resistant sessile life form, called biofilm. Recently, two derivatives of the frog skin antimicrobial peptide esculentin-1a, i.e. Esc(1-21) and its D-amino acids containing diastereomer Esc(1-21)-1c, were characterized for their powerful anti-Pseudomonal activity against both forms. Prevention of biofilm formation already in its early stages could be even more advantageous for counteracting infections induced by this bacterium. In this work, we studied how the diastereomer Esc(1-21)-1c can inhibit Pseudomonas biofilm formation in comparison to the parent peptide and two clinically-used conventional antibiotics, i.e. colistin and aztreonam, when applied at dosages below the minimal growth inhibitory concentration. Biofilm prevention was correlated to the peptides' ability to inhibit Pseudomonas motility and to reduce the production of virulent metabolites, for example, pyoverdine and rhamnolipids. Furthermore, the molecular mechanism underlying these activities was evaluated by studying the peptides' effect on the expression of key genes involved in the virulence and motility of bacteria, as well as by monitoring the peptides' binding to the bacterial signaling nucleotide ppGpp. Our results demonstrate that the presence of only two D-amino acids in Esc(1-21)-1c is sufficient to downregulate ppGpp-mediated expression of biofilm-associated genes, presumably as a result of higher peptide stability and therefore prolonged interaction with the nucleotide. Overall, these studies should assist efficient design and optimization of new anti-infective agents with multiple pharmacologically beneficial properties.}, } @article {pmid31143408, year = {2019}, author = {Conrads, G and Wendt, LK and Hetrodt, F and Deng, ZL and Pieper, D and Abdelbary, MMH and Barg, A and Wagner-Döbler, I and Apel, C}, title = {Deep sequencing of biofilm microbiomes on dental composite materials.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1617013}, pmid = {31143408}, issn = {2000-2297}, abstract = {Background: The microbiome on dental composites has not been studied in detail before. It has not been conclusively clarified whether restorative materials influence the oral microbiome. Methods: We used Illumina Miseq next-generation sequencing of the 16S V1-V2 region to compare the colonisation patterns of bovine enamel (BE) and the composite materials Grandio Flow (GF) and Grandio Blocs (GB) after 48 h in vivo in 14 volunteers. Applying a new method to maintain the oral microbiome ex vivo for 48 h also, we compared the microbiome on GF alone and with the new antimicrobial substance carolacton (GF+C). Results: All in vitro biofilm communities showed a higher diversity and richness than those grown in vivo but the very different atmospheric conditions must be considered. Contrary to expectations, there were only a few significant differences between BE and the composite materials GB and GF either in vivo or in vitro: Oribacterium, Peptostreptococcaceae [XI][G-1] and Streptococcus mutans were more prevalent and Megasphaera, Prevotella oulorum, Veillonella atypica, V. parvula, Gemella morbillorum, and Fusobacterium periodonticum were less prevalent on BE than on composites. In vivo, such preferences were only significant for Granulicatella adiacens (more prevalent on BE) and Fusobacterium nucleatum subsp. animalis (more prevalent on composites). On DNA sequence level, there were no significant differences between the biofilm communities on GF and GF+C. Conclusion: We found that the oral microbiome showed an increased richness when grown on various composites compared to BE in vitro, but otherwise changed only slightly independent of the in vivo or in vitro condition. Our new ex vivo biofilm model might be useful for pre-clinical testing of preventive strategies.}, } @article {pmid31142622, year = {2019}, author = {Sweeney, EG and Nishida, A and Weston, A and Bañuelos, MS and Potter, K and Conery, J and Guillemin, K}, title = {Agent-Based Modeling Demonstrates How Local Chemotactic Behavior Can Shape Biofilm Architecture.}, journal = {mSphere}, volume = {4}, number = {3}, pages = {}, pmid = {31142622}, issn = {2379-5042}, support = {P01 GM125576/GM/NIGMS NIH HHS/United States ; R01 DK101314/DK/NIDDK NIH HHS/United States ; T32 GM007759/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Chemotaxis ; *Computer Simulation ; Helicobacter pylori/*physiology ; Homoserine/analogs & derivatives/metabolism ; Lactones/metabolism ; Quorum Sensing ; }, abstract = {Bacteria are often found living in aggregated multicellular communities known as biofilms. Biofilms are three-dimensional structures that confer distinct physical and biological properties to the collective of cells living within them. We used agent-based modeling to explore whether local cellular interactions were sufficient to give rise to global structural features of biofilms. Specifically, we asked whether chemorepulsion from a self-produced quorum-sensing molecule, autoinducer-2 (AI-2), was sufficient to recapitulate biofilm growth and cellular organization observed for biofilms of Helicobacter pylori, a common bacterial resident of human stomachs. To carry out this modeling, we modified an existing platform, Individual-based Dynamics of Microbial Communities Simulator (iDynoMiCS), to incorporate three-dimensional chemotaxis, planktonic cells that could join or leave the biofilm structure, and cellular production of AI-2. We simulated biofilm growth of previously characterized H. pylori strains with various AI-2 production and sensing capacities. Using biologically plausible parameters, we were able to recapitulate both the variation in biofilm mass and cellular distributions observed with these strains. Specifically, the strains that were competent to chemotax away from AI-2 produced smaller and more heterogeneously spaced biofilms, whereas the AI-2 chemotaxis-defective strains produced larger and more homogeneously spaced biofilms. The model also provided new insights into the cellular demographics contributing to the biofilm patterning of each strain. Our analysis supports the idea that cellular interactions at small spatial and temporal scales are sufficient to give rise to larger-scale emergent properties of biofilms.IMPORTANCE Most bacteria exist in aggregated, three-dimensional structures called biofilms. Although biofilms play important ecological roles in natural and engineered settings, they can also pose societal problems, for example, when they grow in plumbing systems or on medical implants. Understanding the processes that promote the growth and disassembly of biofilms could lead to better strategies to manage these structures. We had previously shown that Helicobacter pylori bacteria are repulsed by high concentrations of a self-produced molecule, AI-2, and that H. pylori mutants deficient in AI-2 sensing form larger and more homogeneously spaced biofilms. Here, we used computer simulations of biofilm formation to show that local H. pylori behavior of repulsion from high AI-2 could explain the overall architecture of H. pylori biofilms. Our findings demonstrate that it is possible to change global biofilm organization by manipulating local cell behaviors, which suggests that simple strategies targeting cells at local scales could be useful for controlling biofilms in industrial and medical settings.}, } @article {pmid31142260, year = {2019}, author = {Lima, MR and Ferreira, GF and Nunes Neto, WR and Monteiro, JM and Santos, ÁRC and Tavares, PB and Denadai, ÂML and Bomfim, MRQ and Dos Santos, VL and Marques, SG and de Souza Monteiro, A}, title = {Evaluation of the interaction between polymyxin B and Pseudomonas aeruginosa biofilm and planktonic cells: reactive oxygen species induction and zeta potential.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {115}, pmid = {31142260}, issn = {1471-2180}, mesh = {Biofilms/drug effects ; Microbial Sensitivity Tests ; Plankton/drug effects/metabolism ; Polymyxin B/*pharmacology ; Pseudomonas aeruginosa/drug effects/*growth & development/metabolism ; Reactive Oxygen Species/*metabolism ; }, abstract = {BACKGROUND: Although the most widely accepted mechanism of action for polymyxins is related to bacterial lysis via disruption, we hypothesized that this antimicrobial drug class could have other effects on Pseudomonas aeruginosa planktonic and sessile cells. Little is known regarding oxidative burst and zeta potential (ZP) data associated with the interaction between polymyxin B and P. aeruginosa cells. The present study evaluated endogenous reactive oxygen species (ROS) production and changes in the net charges of biofilm and planktonic cells in response to polymyxin B.

RESULTS: Polymyxin B induced concentration-dependent killing at all concentrations tested in planktonic and sessile cells from P. aeruginosa strains. Sublethal concentrations of polymyxin B induced oxidative burst. ROS production was higher in resistant planktonic cells than in biofilm cells but this was not observed for susceptible cells. Moreover, no net surface charge alterations were observed in planktonic cells from a susceptible strain treated with polymyxin B, but a significant increase of ZP was noted in planktonic cells from a resistant strain.

CONCLUSION: Oxidative burst generated by planktonic and sessile cells from P. aeruginosa strains against polymyxin B indicates that ROS may have an important role in the mechanism of action of this drug. ZP data revealed that electrostatic interactions of the cationic peptide with the anionic surface of the cells are strain-dependent. Therefore, we suggested that the intracellular effects of polymyxin B should be further investigated to understand polymyxin B-induced stress in P. aeruginosa.}, } @article {pmid31142151, year = {2019}, author = {Song, P and Zhou, B and Feng, G and Brooks, JP and Zhou, H and Zhao, Z and Liu, Y and Li, Y}, title = {The influence of chlorination timing and concentration on microbial communities in labyrinth channels: implications for biofilm removal.}, journal = {Biofouling}, volume = {35}, number = {4}, pages = {401-415}, doi = {10.1080/08927014.2019.1600191}, pmid = {31142151}, issn = {1029-2454}, mesh = {*Biofilms ; Chlorine/*metabolism ; Halogenation ; *Microbiota ; }, abstract = {Chlorination is an effective method to control biofilm formation in enclosed pipelines. To date, very little is known about how to control biofilms at the mesoscale in complex pipelines through chlorination. In this study, the dynamic of microbial communities was examined under different residual chlorine concentrations on the biofilms attached to labyrinth channels for drip irrigation using reclaimed water. The results indicated that the microbial phospholipid fatty acids, extracellular polymeric substances, microbial dynamics, and the ace and Shannon microbial diversity indices showed a gradual decrease after chlorination. However, chlorination increased microbial activity by 0.5-19.2%. The increase in the relative abundances of chloride-resistant bacteria (Acinetobacter and Thermomonas) could lead to a potential risk of chlorine resistance. Thus, keeping a low chlorine concentration (0.83 mg l[-1] for 3 h) is effective for controlling biofilm formation in the labyrinth channels.}, } @article {pmid31141557, year = {2019}, author = {McGinniss, JE and Imai, I and Simon-Soro, A and Brown, MC and Knecht, VR and Frye, L and Ravindran, PM and Dothard, MI and Wadell, DA and Sohn, MB and Li, H and Christie, JD and Diamond, JM and Haas, AR and Lanfranco, AR and DiBardino, DM and Bushman, FD and Collman, RG}, title = {Molecular analysis of the endobronchial stent microbial biofilm reveals bacterial communities that associate with stent material and frequent fungal constituents.}, journal = {PloS one}, volume = {14}, number = {5}, pages = {e0217306}, pmid = {31141557}, issn = {1932-6203}, support = {R01 HL113252/HL/NHLBI NIH HHS/United States ; T32 HL007586/HL/NHLBI NIH HHS/United States ; P30 AI045008/AI/NIAID NIH HHS/United States ; P30 CA016520/CA/NCI NIH HHS/United States ; U01 HL098957/HL/NHLBI NIH HHS/United States ; R61 HL137063/HL/NHLBI NIH HHS/United States ; U01 HL112712/HL/NHLBI NIH HHS/United States ; R33 HL137063/HL/NHLBI NIH HHS/United States ; }, mesh = {Bacteria/genetics ; Biofilms/growth & development ; Bronchi/microbiology/surgery ; Female ; Fungi/genetics ; Humans ; Male ; Microbiota ; RNA, Ribosomal, 16S/genetics ; Stents/*adverse effects/*microbiology ; }, abstract = {Endobronchial stents are increasingly used to treat airway complications in multiple conditions including lung transplantation but little is known about the biofilms that form on these devices. We applied deep sequencing to profile luminal biofilms of 46 endobronchial stents removed from 20 subjects primarily with lung transplantation-associated airway compromise. Microbial communities were analyzed by bacterial 16S rRNA and fungal ITS marker gene sequencing. Corynebacterium was the most common bacterial taxa across biofilm communities. Clustering analysis revealed three bacterial biofilm types: one low diversity and dominated by Corynebacterium; another was polymicrobial and characterized by Staphylococcus; and the third was polymicrobial and associated with Pseudomonas, Streptococcus, and Prevotella. Biofilm type was significantly correlated with stent material: covered metal with the Staphylococcus-type biofilm, silicone with the Corynebacterium-dominated biofilm, and uncovered metal with the polymicrobial biofilm. Subjects with sequential stents had frequent transitions between community types. Fungal analysis found Candida was most prevalent, Aspergillus was common and highly enriched in two of three stents associated with airway anastomotic dehiscence, and fungal taxa not typically considered pathogens were highly enriched in some stents. Thus, molecular analysis revealed a complex and dynamic endobronchial stent biofilm with three bacterial types that associate with stent material, a central role for Corynebacterium, and that both expected and unexpected fungi inhabit this unique niche. The current work provides a foundation for studies to investigate the relationship between stent biofilm composition and clinical outcomes, mechanisms of biofilm establishment, and strategies for improved stent technology and use in airway compromise.}, } @article {pmid31141184, year = {2019}, author = {Wang, C and Zhang, Q and Wang, Y and Tang, X and An, Y and Li, S and Xu, H and Li, Y and Luan, W and Wang, X and Liu, M and Yu, L}, title = {Comparative proteomics analysis between biofilm and planktonic cells of Mycobacterium tuberculosis.}, journal = {Electrophoresis}, volume = {40}, number = {20}, pages = {2736-2746}, doi = {10.1002/elps.201900030}, pmid = {31141184}, issn = {1522-2683}, support = {2017YFD0502200//Key Project of Research and Development Plan/International ; 2016YFD0501302//Key Project of Research and Development Plan/International ; 31172364//National Nature Science Foundation of China/International ; 81801972//National Nature Science Foundation of China/International ; 20150101108JC//Fund for Science & Technology Development of Jilin Province/International ; 2012ZX10003002//Important National Science and Technology Specific Projects/International ; NCET-09-0434//Program for New Century Excellent Talents in University/International ; 2016444//Project of the Education Department of Jilin Province/International ; JCYJ2016031100720906//Technology and Innovation Commission of Shenzhen Municipality/International ; JSGG20160301100442775//Technology and Innovation Commission of Shenzhen Municipality/International ; }, mesh = {Bacterial Proteins/*analysis/metabolism ; *Biofilms ; *Mycobacterium tuberculosis/chemistry/cytology/metabolism/physiology ; Protein Interaction Maps/physiology ; Proteome/*analysis/metabolism ; Proteomics/*methods ; }, abstract = {Tuberculosis is highly persistent and displays phenotypic resistance to high concentrations of antimicrobials. Recent reports exhibited that Mycobacterium tuberculosis biofilm was implicated to its pathogenicity and drug resistance. In this study, there were 47 kinds of differential proteins in the biofilm of M. tuberculosis H37Rv cells compared with the planktonic bacteria, and 37 proteins were nonredundant and identified by proteomics approach, such as 2DE and LC-MS/MS. Moreover, six kinds of proteins were identified as HspX, which were conservative and highly expressed in biofilm. Note that 47 differential proteins were divided into seven categories, such as cell wall and cell processes, conserved hypotheticals, intermediary metabolism and respiration, and so on by TUBERCULIST. The Gene Ontology classification results showed that the largest protein group involved in metabolism, binding proteins, and catalytic function accounts for 30% and 57% of all identified proteins, respectively. Moreover, the protein interaction network analyzed by STRING showed that the minority proteins such as RpoA, SucC, Cbs, Tuf, DnaK, and GroeL in the interaction network have high network connectivity. These results implied that the proteins involved in metabolic process and catalytic function and the minority proteins mentioned above may play an important role in M. tuberculosis biofilm formation. To our knowledge, this is the first report about differential proteins between biofilm and planktonic M. tuberculosis, which provided the potential antigens for vaccines and target proteins for anti-mycobacterial drugs.}, } @article {pmid31139155, year = {2019}, author = {Manna, S and Ghosh, AK and Mandal, SM}, title = {Curd-Peptide Based Novel Hydrogel Inhibits Biofilm Formation, Quorum Sensing, Swimming Mortility of Multi-Antibiotic Resistant Clinical Isolates and Accelerates Wound Healing Activity.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {951}, pmid = {31139155}, issn = {1664-302X}, abstract = {The search for a bioactive natural antibacterial agent with wound healing properties is a common practice for the development of new-generation molecules. Antimicrobial peptides are a good alternative to antibiotics and easy-to-form hydrogels under self-assembled conditions without pH adjustment. With this in mind, the peptide pool was extracted from a formulated curd composed of a blend of probiotic bacteria such as Streptococcus thermophilus, Lactobacillus casei, and Bifidobacterium bifidum at an optimized ratio of 7:1:2. The water content of curd was collected by the drainage column, centrifuged, filtered through a 0.45-μM filter, and used for hydrogel preparation. Matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS) analysis confirmed the presence of peptide pool in the extracted water. The prepared hydrogel was freeze dried, and its effect on biofilm formation, swarming mortality, antimicrobials, wound healing, and biocompatibility was subsequently verified. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images revealed the fibrous network of peptides after self-assembly with non-polar n-hexane solvent and a porous structure after drying, respectively. The observed biocompatibility, antimicrobial activity, and strong wound healing activity of the developed curd-based hydrogel have opened a new platform for antibacterial ointment formulation.}, } @article {pmid31138626, year = {2019}, author = {Greenwich, J and Reverdy, A and Gozzi, K and Di Cecco, G and Tashjian, T and Godoy-Carter, V and Chai, Y}, title = {A Decrease in Serine Levels during Growth Transition Triggers Biofilm Formation in Bacillus subtilis.}, journal = {Journal of bacteriology}, volume = {201}, number = {15}, pages = {}, pmid = {31138626}, issn = {1098-5530}, mesh = {Bacillus subtilis/genetics/growth & development/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Serine/*metabolism ; }, abstract = {Biofilm development in Bacillus subtilis is regulated at multiple levels. While a number of known signals that trigger biofilm formation do so through the activation of one or more sensory histidine kinases, it was discovered that biofilm activation is also coordinated by sensing intracellular metabolic signals, including serine starvation. Serine starvation causes ribosomes to pause on specific serine codons, leading to a decrease in the translation rate of sinR, which encodes a master repressor for biofilm matrix genes and ultimately triggers biofilm induction. How serine levels change in different growth stages, how B. subtilis regulates intracellular serine levels, and how serine starvation triggers ribosomes to pause on selective serine codons remain unknown. Here, we show that serine levels decrease as cells enter stationary phase and that unlike most other amino acid biosynthesis genes, expression of serine biosynthesis genes decreases upon the transition into stationary phase. The deletion of the gene for a serine deaminase responsible for converting serine to pyruvate led to a delay in biofilm formation, further supporting the idea that serine levels are a critical intracellular signal for biofilm activation. Finally, we show that levels of all five serine tRNA isoacceptors are decreased in stationary phase compared with exponential phase. However, the three isoacceptors recognizing UCN serine codons are reduced to a much greater extent than the two that recognize AGC and AGU serine codons. Our findings provide evidence for a link between serine homeostasis and biofilm development in B. subtilisIMPORTANCE In Bacillus subtilis, biofilm formation is triggered in response to environmental and cellular signals. It was proposed that serine limitation acts as a proxy for nutrient status and triggers biofilm formation at the onset of biofilm entry through a novel signaling mechanism caused by global ribosome pausing on selective serine codons. In this study, we reveal that serine levels decrease at the biofilm entry due to catabolite control and a serine shunt mechanism. We also show that levels of five serine tRNA isoacceptors are differentially decreased in stationary phase compared with exponential phase; three isoacceptors recognizing UCN serine codons are reduced much more than the two recognizing AGC and AGU codons. This finding indicates a possible mechanism for selective ribosome pausing.}, } @article {pmid31138130, year = {2019}, author = {Dakheel, KH and Rahim, RA and Neela, VK and Al-Obaidi, JR and Hun, TG and Isa, MNM and Yusoff, K}, title = {Genomic analyses of two novel biofilm-degrading methicillin-resistant Staphylococcus aureus phages.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {114}, pmid = {31138130}, issn = {1471-2180}, mesh = {Biofilms/*growth & development ; Genome Size ; *Genome, Viral ; Humans ; Methicillin-Resistant Staphylococcus aureus/growth & development/*virology ; Open Reading Frames ; Phylogeny ; Plankton/growth & development ; Staphylococcus Phages/classification/genetics/*physiology ; }, abstract = {BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) biofilm producers represent an important etiological agent of many chronic human infections. Antibiotics and host immune responses are largely ineffective against bacteria within biofilms. Alternative actions and novel antimicrobials should be considered. In this context, the use of phages to destroy MRSA biofilms presents an innovative alternative mechanism.

RESULTS: Twenty-five MRSA biofilm producers were used as substrates to isolate MRSA-specific phages. Despite the difficulties in obtaining an isolate of this phage, two phages (UPMK_1 and UPMK_2) were isolated. Both phages varied in their ability to produce halos around their plaques, host infectivity, one-step growth curves, and electron microscopy features. Furthermore, both phages demonstrated antagonistic infectivity on planktonic cultures. This was validated in an in vitro static biofilm assay (in microtiter-plates), followed by the visualization of the biofilm architecture in situ via confocal laser scanning microscopy before and after phage infection, and further supported by phages genome analysis. The UPMK_1 genome comprised 152,788 bp coding for 155 putative open reading frames (ORFs), and its genome characteristics were between the Myoviridae and Siphoviridae family, though the morphological features confined it more to the Siphoviridae family. The UPMK_2 has 40,955 bp with 62 putative ORFs; morphologically, it presented the features of the Podoviridae though its genome did not show similarity with any of the S. aureus in the Podoviridae family. Both phages possess lytic enzymes that were associated with a high ability to degrade biofilms as shown in the microtiter plate and CLSM analyses.

CONCLUSIONS: The present work addressed the possibility of using phages as potential biocontrol agents for biofilm-producing MRSA.}, } @article {pmid31136790, year = {2019}, author = {Alkhudhairy, MK and Alshadeedi, SMJ and Mahmood, SS and Al-Bustan, SA and Ghasemian, A}, title = {Comparison of adhesin genes expression among Klebsiella oxytoca ESBL-non-producers in planktonic and biofilm mode of growth, and imipenem sublethal exposure.}, journal = {Microbial pathogenesis}, volume = {134}, number = {}, pages = {103558}, doi = {10.1016/j.micpath.2019.103558}, pmid = {31136790}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/drug effects/*genetics ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/*growth & development ; Carbapenems/pharmacology ; Gene Expression Regulation, Bacterial/drug effects/*genetics ; Genes, Bacterial/genetics ; Humans ; Imipenem/*pharmacology ; Klebsiella Infections/microbiology ; Klebsiella oxytoca/*drug effects/*genetics/isolation & purification ; Microbial Sensitivity Tests ; Phenotype ; beta-Lactamases/genetics ; beta-Lactams/pharmacology ; }, abstract = {BACKGROUND: Bacterial adhesins play an important role in the bacterial attachment and colonization. The aim of this study was comparison of adhesin genes expression in the planktonic and biofilm mode of growth among ESBL-non-producers isolates of K. oxytoca and effect of imipenem.

MATERIALS AND METHODS: A total of eight extended-spectrum beta-lactamase (ESBL) non-producer K. oxytoca isolates were included from patients with hemorrhagic colitis. The adhesin genes including fimA (type 1 fimbria), mrkA (type 3 fimbria), pilQ and the capsular matB genes were adopted. Phenotypic biofilm production was assessed by microtiter tissue plate assay. Expression of adhesin genes in the planktonic and biofilm growth conditions was calculated using quantitative Real-time PCR (RT-qPCR) technique and sub-MIC (0.25 μg/ml) levels of imipenem were also added to broth culture of isolates to evaluate the gene expression.

RESULTS: The isolates produced biofilm in moderate level. The expression of pilQ, mrkA and matB but not fimA genes was significantly higher in biofilm conditions compared to the planktonic mode of growth (p = 0.002, p = 0.011 and p = 001, respectively). In addition, imipenem sub-MIC treatment led to a significant overexpression of matB (p = 0.002) and mrkA (p = 0.003) genes compared to the control group.

CONCLUSION: Although none of isolates produced strong biofilm, biofilm conditions led to the increase in the expression of adhesin encoding genes in non-ESBL-producing K. oxytoca. Furthermore, β-lactams; and especially carbapenems possibly increase the colonization of K. oxytoca and increase the biofilm formation. Hence, accurate consumption of antibiotics must be considered.}, } @article {pmid31136296, year = {2019}, author = {Ghasemian, A and Mohabati Mobarez, A and Najar Peerayeh, S and Talebi Bezmin Abadi, A and Khodaparast, S and Mahmood, SS}, title = {Expression of adhesin genes and biofilm formation among Klebsiella oxytoca clinical isolates from patients with antibiotic-associated haemorrhagic colitis.}, journal = {Journal of medical microbiology}, volume = {68}, number = {7}, pages = {978-985}, doi = {10.1099/jmm.0.000965}, pmid = {31136296}, issn = {1473-5644}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/adverse effects ; Biofilms/*growth & development ; Child ; Child, Preschool ; Colitis/*microbiology/pathology ; Feces/microbiology ; Female ; Gastrointestinal Hemorrhage/*microbiology/pathology ; Gene Expression Regulation, Bacterial/*physiology ; Humans ; Infant ; Klebsiella Infections/microbiology ; Klebsiella oxytoca/drug effects/genetics/*metabolism/physiology ; Male ; Middle Aged ; Real-Time Polymerase Chain Reaction ; Young Adult ; }, abstract = {PURPOSE: Biofilm formation and resistance to last-line antibiotics have restricted chemotherapy options toward infection eradication.

METHODOLOGY: Fifty K. oxytoca isolates were collected from patients with antibiotic-associated haemorrhagic colitis (AAHC). Antibiotic susceptibility tests were conducted and phenotypic biofilm formation was assessed using microtitre tissue plate (MTP) assay. PCR was employed to amplify the adhesins, extended-spectrum β-lactamases (ESBLs), carbapenemase and colistin resistance genes. The expression of adhesin genes was evaluated using quantitative real-time PCR (RT-qPCR).Results/Key findings. The previous antibiotic consumption and hospitalization (P<0.05) and older ages (P=0.0033) were significantly associated with AAHC. None of the isolates produced biofilm strongly, but 70% of them produced moderate-level biofilm. The blaCTX-M (12/14), the blaIMP (8/14 MICIMI =4 µg ml[-1]) and blaOXA-48-like (5/14) and mcr-1 (4/14) genes were predominant, three of which harbouring all the genes. The expression of matB (0.023) and mrkA (0.011) was significantly different between multidrug-resistant and susceptible isolates. Furthermore, moderately biofilm producer isolates significantly exhibited higher expression of fimA (P=.0117), pilQ (P=0.002) and mrkA (P=0.020) genes compared to biofilm non-producers. No significant difference regarding gene expression was observed among ESBL alleles.

CONCLUSION: Bacterial attachment by adhesins and biofilm formation among extensive drug-resistant K. oxytoca isolates hinder the efficient infection eradication. Hence, control and surveillance studies should be performed and other therapeutic auspicious approaches must be taken into account against AAHC, biofilm formation and drug resistance spread. Furthermore, previous antibiotic consumption and long-term hospitalization should be controlled.}, } @article {pmid31135555, year = {2019}, author = {Tsikopoulos, K and Bidossi, A and Drago, L and Petrenyov, DR and Givissis, P and Mavridis, D and Papaioannidou, P}, title = {Is Implant Coating With Tyrosol- and Antibiotic-loaded Hydrogel Effective in Reducing Cutibacterium (Propionibacterium) acnes Biofilm Formation? A Preliminary In Vitro Study.}, journal = {Clinical orthopaedics and related research}, volume = {477}, number = {7}, pages = {1736-1746}, pmid = {31135555}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Humans ; Hydrogels/pharmacology ; Microbial Sensitivity Tests ; Phenylethyl Alcohol/*analogs & derivatives/pharmacology ; Propionibacteriaceae/*drug effects ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/microbiology ; Titanium ; }, abstract = {BACKGROUND: Studies have suggested that Cutibacterium acnes (formerly known as Propionibacterium) is the most frequently isolated pathogen after shoulder arthroplasty. To address the burden of periprosthetic joint infections associated with this pathogen, new prevention methods are needed. Tyrosol has a promising record of effectiveness in the field of biofilm-associated infections; however, to our knowledge, it has not been tested against C. acnes thus far.

QUESTIONS/PURPOSES: In this in vitro study, we asked: (1) Is tyrosol effective in inhibiting and eradicating C. acnes planktonic growth? (2) Is there synergy between tyrosol and rifampicin? (3) Is supplementation of hydrogel with tyrosol at the minimum inhibitory and subinhibitory concentrations efficacious in reducing free-floating C. acnes growth? (4) Is implant hydrogel coating (either alone or combined with tyrosol, rifampicin, or vancomycin) beneficial in reducing C. acnes biofilm formation? (5) Is the administration of soluble tyrosol an effective measure against C. acnes biofilm formation?

METHODS: We assessed C. acnes planktonic growth and eradication by inspecting visually the results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. We also evaluated macroscopically the presence of synergy among tyrosol and rifampicin by means of the MIC checkerboard testing. Thereafter, we addressed colorimetrically the efficacy of tyrosol-loaded Defensive Antibacterial Coating (DAC®) hydrogel against the C. acnes free-floating form by means of the XTT cell proliferation reduction assay. Then, we explored photometrically the effect of hydrogel and soluble tyrosol at reducing C. acnes biofilm formation on titanium alloy disks that simulated orthopaedic implants by using the minimum biofilm inhibition concentration assay. In particular, 16 disks were sequentially allocated to each of the following testing conditions: (1) hydrogel alone; (2) tyrosol-loaded hydrogel; (3) rifampicin-supplemented hydrogel; (4) vancomycin-loaded hydrogel; and (5) soluble tyrosol. Subsequently, implants were sonicated and cell viability was evaluated in terms of the XTT assay.

RESULTS: Tyrosol was effective in inhibiting C. acnes planktonic (free-floating) growth demonstrating MIC values of 63 mM (9 mg/mL) and MBC values of 250 mM (35 mg/mL). Concerning synergy assessment, the checkerboard testing revealed additivity among tyrosol and rifampicin with a fractional inhibitory concentration index of 0.56. In addition, a hydrogel coating with tyrosol at the MIC showed no difference in the inhibition of free-floating C. Acnes form over control (median absorbance [MA] for tyrosol-supplemented hydrogel versus control groups were 0.21 [interquartile range {IQR}, 0.19-0.24] versus 0.26 [IQR, 0.23-0.31], p = 0.066). Furthermore, loaded hydrogel with tyrosol at 597 mg/mL (1 M) was no more effective than control in reducing C. acnes biofilm formation (MAs for tyrosol versus control were 0.12 [IQR, 0.11-0.13] versus 0.14 [IQR, 0.12-0.16], respectively; p = 0.076). This was also the case when we considered hydrogel in conjunction with vancomycin and rifampicin (MAs for vancomycin at 2% and 5% and rifampicin at 1% versus biofilm control were 0.139 [IQR, 0.133-0.143] and 0.141 [IQR, 0.133-0.143] and 0.135 [IQR, 0.128-0.146] versus 0.142 [IQR, 0.136-0.144], correspondingly). In contrast, soluble tyrosol at 597 mg/mL (1 M) inhibited biofilm formation compared to control (MAs for tyrosol and control groups were 0.11 [IQR, 0.09-0.13] versus 0.13 [IQR, 0.12-0.14], p = 0.007).

CONCLUSIONS: Although the implant coating with hydrogel (either pure or supplemented with antimicrobial agents) did not diminish C. acnes biofilm development in vitro, soluble tyrosol at 597 mg/mL (1 M) exceeded the meaningful biofilm inhibition threshold of 80%.

CLINICAL RELEVANCE: The results of the current preclinical investigation did not support the use of a fast, bioresorbable hydrogel as a coating method against C. acnes biofilms. Instead, direct local administration of soluble tyrosol at high concentrations should be further tested in future animal studies.}, } @article {pmid31134579, year = {2019}, author = {Córdova-Alcántara, IM and Venegas-Cortés, DL and Martínez-Rivera, MÁ and Pérez, NO and Rodriguez-Tovar, AV}, title = {Biofilm characterization of Fusarium solani keratitis isolate: increased resistance to antifungals and UV light.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {6}, pages = {485-497}, pmid = {31134579}, issn = {1976-3794}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/*growth & development/*radiation effects ; Drug Resistance, Fungal/drug effects/radiation effects ; Eye Infections, Fungal/*microbiology ; Fungi/drug effects/radiation effects ; Fusarium/*drug effects/pathogenicity/*radiation effects ; Humans ; Hyphae/drug effects/radiation effects ; Keratitis/*microbiology ; Mexico ; Microbial Sensitivity Tests ; Microbial Viability/drug effects/radiation effects ; Microscopy, Electron, Scanning ; }, abstract = {Fusarium solani has drawn phytopathogenic, biotechnological, and medical interest. In humans, it is associated with localized infections, such as onychomycosis and keratomycosis, as well as invasive infections in immunocompromised patients. One pathogenicity factor of filamentous fungi is biofilm formation. There is still only scarce information about the in vitro mechanism of the formation and composition of F. solani biofilm. In this work, we describe the biofilm formed by a clinical keratomycosis isolate in terms of its development, composition and susceptibility to different antifungals and ultraviolet light (UV) at different biofilm formation stages. We found five biofilm formation stages using scanning electron microscopy: adherence, germination, hyphal development, maturation, and cell detachment. Using epifluorescence microscopy with specific fluorochromes, it was elucidated that the extracellular matrix consists of carbohydrates, proteins, and extracellular DNA. Specific inhibitors for these molecules showed significant biofilm reductions. The antifungal susceptibility against natamycin, voriconazole, caspofungin, and amphotericin B was evaluated by metabolic activity and crystal violet assay, with the F. solani biofilm preformation to 24 h increased in resistance to natamycin, voriconazole, and caspofungin, while the biofilm preformation to 48 h increased in resistance to amphotericin B. The preformed biofilm at 24 h protected and reduced UV light mortality. F. solani isolate could produce a highly structured extra biofilm; its cellular matrix consists of carbohydrate polymers, proteins, and eDNA. Biofilm confers antifungal resistance and decreases its susceptibility to UV light. The fungal biofilm functions as a survival strategy against antifungals and environmental factors.}, } @article {pmid31134255, year = {2019}, author = {Gupta, A and Holoidovsky, L and Thamaraiselvan, C and Thakur, AK and Singh, SP and Meijler, MM and Arnusch, CJ}, title = {Silver-doped laser-induced graphene for potent surface antibacterial activity and anti-biofilm action.}, journal = {Chemical communications (Cambridge, England)}, volume = {55}, number = {48}, pages = {6890-6893}, doi = {10.1039/c9cc02415h}, pmid = {31134255}, issn = {1364-548X}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*chemistry ; Graphite/*chemistry ; Lasers ; Metal Nanoparticles/*chemistry ; Polymers/chemistry ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry ; Sulfones/chemistry ; Surface Properties ; }, abstract = {Previously, laser-induced graphene (LIG) coated surfaces were shown to resist biofilm growth, although the material was not strongly antibacterial. Here, we show LIG surfaces doped with silver nanoparticles (Ag0 or AgNPs) as highly antibacterial surfaces. Starting from AgNO3 polyethersulfone (PES) polymer substrates, silver nanoparticles between 5-10 nm were generated in situ during the lasing process and stably embedded in the fibrous and porous structure of LIG in a single step. These silver doped LIG (Ag@LIG) surfaces were highly toxic to bacteria via a mechanism of both Ag+ ion release and possible surface toxicity of the AgNPs. The added antibacterial function of Ag-nanoparticles expands the functionality of LIG coated surfaces and might lead to highly effective point of use/entry devices in rural areas or in disaster situations with contaminated water sources.}, } @article {pmid31134027, year = {2019}, author = {Maudsdotter, L and Ushijima, Y and Morikawa, K}, title = {Fitness of Spontaneous Rifampicin-Resistant Staphylococcus aureus Isolates in a Biofilm Environment.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {988}, pmid = {31134027}, issn = {1664-302X}, abstract = {Biofilms of S. aureus accumulate cells resistant to the antibiotic rifampicin. We show here that the accumulation of rifampicin resistant mutants (RifR) in biofilms is not equable but rather is a local event, suggesting that the growth of a few locally emerged mutants is responsible for this. Competition assays demonstrated that, compared to wild-type bacteria, the isolated RifR mutants have a growth advantage in biofilms, but not in planktonic culture. To gain insight into the mechanism of the growth advantage, we tested the involvement of the two-component systems (TCS) that sense and respond to environmental changes. We found that a deletion of SrrAB or NreBC has a drastic effect on the growth advantage of RifR mutants, suggesting the importance of oxygen/respiration responses. All six of the RifR isolates tested showed increased resistance to at least one of the common stresses found in the biofilm environment (i.e., oxidative, nitric acid, and organic acid stress). The RifR mutants also had a growth advantage in a biofilm flow model, which highlights the physiological relevance of our findings.}, } @article {pmid31133998, year = {2019}, author = {Zhang, R and Neu, TR and Li, Q and Blanchard, V and Zhang, Y and Schippers, A and Sand, W}, title = {Insight Into Interactions of Thermoacidophilic Archaea With Elemental Sulfur: Biofilm Dynamics and EPS Analysis.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {896}, pmid = {31133998}, issn = {1664-302X}, abstract = {Biooxidation of reduced inorganic sulfur compounds (RISCs) by thermoacidophiles is of particular interest for the biomining industry and for environmental issues, e.g., formation of acid mine drainage (AMD). Up to now, interfacial interactions of acidophiles with elemental sulfur as well as the mechanisms of sulfur oxidation by acidophiles, especially thermoacidophiles, are not yet fully clear. This work focused on how a crenarchaeal isolate Acidianus sp. DSM 29099 interacts with elemental sulfur. Analysis by Confocal laser scanning microscopy (CLSM) and Atomic force microscopy (AFM) in combination with Epifluorescence microscopy (EFM) shows that biofilms on elemental sulfur are characterized by single colonies and a monolayer in first stage and later on 3-D structures with a diameter of up to 100 μm. The analysis of extracellular polymeric substances (EPS) by a non-destructive lectin approach (fluorescence lectin-barcoding analysis) using several fluorochromes shows that intial attachment was featured by footprints rich in biofilm cells that were embedded in an EPS matrix consisting of various glycoconjugates. Wet chemistry data indicate that carbohydrates, proteins, lipids and uronic acids are the main components. Attenuated reflectance (ATR)-Fourier transformation infrared spectroscopy (FTIR) and high-performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) indicate glucose and mannose as the main monosaccharides in EPS polysaccharides. EPS composition as well as sugar types in EPS vary according to substrate (sulfur or tetrathionate) and lifestyle (biofilms and planktonic cells). This study provides information on the building blocks/make up as well as dynamics of biofilms of thermoacidophilic archaea in extremely acidic environments.}, } @article {pmid31133642, year = {2019}, author = {An, SQ and Murtagh, J and Twomey, KB and Gupta, MK and O'Sullivan, TP and Ingram, R and Valvano, MA and Tang, JL}, title = {Modulation of antibiotic sensitivity and biofilm formation in Pseudomonas aeruginosa by interspecies signal analogues.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {2334}, pmid = {31133642}, issn = {2041-1723}, support = {//Wellcome Trust/United Kingdom ; 100304/A/12/Z//Wellcome Trust (Wellcome)/International ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects ; Disease Models, Animal ; Drug Resistance, Bacterial ; Fatty Acids, Unsaturated/*metabolism ; Female ; Gene Expression Regulation, Bacterial/drug effects/immunology ; Histidine Kinase/genetics/*metabolism ; Humans ; Liposomes/metabolism ; Mice ; Mice, Inbred C57BL ; Microbial Sensitivity Tests ; Mutagenesis ; Phosphorylation ; Polymyxins/pharmacology/therapeutic use ; Pseudomonas Infections/*drug therapy/immunology/microbiology ; Pseudomonas aeruginosa/*physiology ; Virulence Factors/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa, a significant opportunistic pathogen, can participate in inter-species communication through signaling by cis-2-unsaturated fatty acids of the diffusible signal factor (DSF) family. Sensing these signals leads to altered biofilm formation and increased tolerance to various antibiotics, and requires the histidine kinase PA1396. Here, we show that the membrane-associated sensory input domain of PA1396 has five transmembrane helices, two of which are required for DSF sensing. DSF binding is associated with enhanced auto-phosphorylation of PA1396 incorporated into liposomes. Further, we examined the ability of synthetic DSF analogues to modulate or inhibit PA1396 activity. Several of these analogues block the ability of DSF to trigger auto-phosphorylation and gene expression, whereas others act as inverse agonists reducing biofilm formation and antibiotic tolerance, both in vitro and in murine infection models. These analogues may thus represent lead compounds to develop novel adjuvants improving the efficacy of existing antibiotics.}, } @article {pmid31133172, year = {2019}, author = {DiBenedetto, D}, title = {Letters: Beyond Biofilm-Based.}, journal = {Journal of the American Dental Association (1939)}, volume = {150}, number = {6}, pages = {484}, doi = {10.1016/j.adaj.2019.04.005}, pmid = {31133172}, issn = {1943-4723}, mesh = {Adolescent ; Biofilms ; *Gingival Hyperplasia ; Humans ; }, } @article {pmid31132246, year = {2019}, author = {Cutrona, N and Gillard, K and Ulrich, R and Seemann, M and Miller, HB and Blackledge, MS}, title = {From Antihistamine to Anti-infective: Loratadine Inhibition of Regulatory PASTA Kinases in Staphylococci Reduces Biofilm Formation and Potentiates β-Lactam Antibiotics and Vancomycin in Resistant Strains of Staphylococcus aureus.}, journal = {ACS infectious diseases}, volume = {5}, number = {8}, pages = {1397-1410}, doi = {10.1021/acsinfecdis.9b00096}, pmid = {31132246}, issn = {2373-8227}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/*drug effects ; Loratadine/*pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Phosphotransferases/*antagonists & inhibitors ; Protein Serine-Threonine Kinases/antagonists & inhibitors ; Receptor Protein-Tyrosine Kinases/antagonists & inhibitors ; Staphylococcus aureus/*drug effects/enzymology ; Staphylococcus epidermidis/*drug effects/enzymology ; Vancomycin/pharmacology ; Virulence Factors/antagonists & inhibitors ; beta-Lactams/pharmacology ; }, abstract = {Staphylococcus epidermidis and Staphylococcus aureus are important human pathogens responsible for two-thirds of all postsurgical infections of indwelling medical devices. Staphylococci form robust biofilms that provide a reservoir for chronic infection, and antibiotic-resistant isolates are increasingly common in both healthcare and community settings. Novel treatments that can simultaneously inhibit biofilm formation and antibiotic-resistance pathways are urgently needed to combat the increasing rates of antibiotic-resistant infections. Herein we report that loratadine, an FDA-approved antihistamine, significantly inhibits biofilm formation in both S. aureus and S. epidermidis. Furthermore, loratadine potentiates β-lactam antibiotics in methicillin-resistant strains of S. aureus and potentiates both β-lactam antibiotics and vancomycin in vancomycin-resistant strains of S. aureus. Additionally, we elucidate loratadine's mechanism of action as a novel inhibitor of the regulatory PASTA kinases Stk and Stk1 in S. epidermidis and S. aureus, respectively. Finally, we describe how Stk1 inhibition affects the expression of genes involved in both biofilm formation and antibiotic resistance in S. epidermidis and S. aureus.}, } @article {pmid31132181, year = {2019}, author = {Singh, R and Kaur, M and Chakrabarti, A and Shankarnarayan, SA and Rudramurthy, SM}, title = {Biofilm formation by Candida auris isolated from colonising sites and candidemia cases.}, journal = {Mycoses}, volume = {62}, number = {8}, pages = {706-709}, doi = {10.1111/myc.12947}, pmid = {31132181}, issn = {1439-0507}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida/drug effects/isolation & purification/*physiology ; Candidemia/*microbiology ; Humans ; Microbial Sensitivity Tests ; Virulence ; }, abstract = {BACKGROUND: Candida auris, an emerging nosocomial pathogen, exhibits phenotypic variation. Non-aggregating C. auris isolates display greater biofilm-forming capacity and virulence than aggregate-forming isolates. Most of the studies till date have focused on clinical isolates. The biofilm-forming capacity of colonising isolates remains uninvestigated.

OBJECTIVES: The present study aimed to elucidate the biofilm-forming capacity of the colonising isolates of C. auris, correlate it with their aggregation behaviour and antifungal susceptibility, and compare it with that of the isolates from blood-stream infection.

METHODS: Colonising and clinical (candidemia) isolates of C. auris were screened for aggregation behaviour, biofilm-forming capacity and antifungal susceptibility testing. Aggregation behaviour was assessed microscopically. Biofilm-forming capacity was determined on 96-well flat-bottomed microtitre plates. Antifungal susceptibility testing was performed by broth microdilution assay.

RESULTS: Aggregative and non-aggregative phenotypes were found to be predominantly associated with colonising and clinical isolates, respectively, with the former ones being stronger biofilm producers in the colonising group. Non-aggregative isolates in the colonising group showed lower susceptibility to amphotericin B and fluconazole than aggregative isolates. In contrast, no association was noted between biofilm formation, aggregation behaviour and antifungal susceptibility amongst the clinical isolates.

CONCLUSION: Biofilm formation is a strain-dependent trait in C. auris, strongly associated with the type and phenotypic behaviour of the isolates. Colonising isolates of this fungus were found to be predominantly aggregative in nature, with a higher biofilm-forming capacity than non-aggregative ones.}, } @article {pmid31131107, year = {2019}, author = {Sharma, D and Misba, L and Khan, AU}, title = {Antibiotics versus biofilm: an emerging battleground in microbial communities.}, journal = {Antimicrobial resistance and infection control}, volume = {8}, number = {}, pages = {76}, pmid = {31131107}, issn = {2047-2994}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/drug therapy/prevention & control/radiotherapy ; Biofilms/*drug effects/radiation effects ; *Drug Resistance, Bacterial ; Humans ; Microbiota/*drug effects ; Photochemotherapy ; Quorum Sensing ; }, abstract = {Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.}, } @article {pmid31129521, year = {2019}, author = {Yang, S and Peng, Y and Zhang, L and Zhang, Q and Li, J and Wang, X}, title = {Autotrophic nitrogen removal in an integrated fixed-biofilm activated sludge (IFAS) reactor: Anammox bacteria enriched in the flocs have been overlooked.}, journal = {Bioresource technology}, volume = {288}, number = {}, pages = {121512}, doi = {10.1016/j.biortech.2019.121512}, pmid = {31129521}, issn = {1873-2976}, mesh = {*Ammonium Compounds ; Bacteria ; Biofilms ; Bioreactors ; Denitrification ; Nitrogen ; Oxidation-Reduction ; *Sewage ; }, abstract = {In this study, an autotrophic nitrogen removal process was established using an integrated fixed-biofilm activated sludge (IFAS) reactor treated with high ammonium wastewater. A nitrogen removal rate (NRR) of 2.78 kg N/(m[3]·d) was obtained during the 206-day operation. Moreover, during the stable period, the large flocs (D > 0.2 mm) had a significantly higher abundance of anammox bacteria than the small flocs (D < 0.2 mm) and biofilm, resulting in 51% of the anammox bacteria being located in the flocs. The result indicates that anammox bacteria can be enriched in the flocs and in the biofilm, which has been rarely reported for IFAS reactors. In addition, the large flocs are likely formed through biofilm detachment since the microbial community was similar for the two kinds of biomass. Overall, the role of flocs in IFAS reactors are complicated and their contribution to the anammox reaction have been overlooked thus far.}, } @article {pmid31129476, year = {2019}, author = {Iñiguez-Moreno, M and Gutiérrez-Lomelí, M and Avila-Novoa, MG}, title = {Kinetics of biofilm formation by pathogenic and spoilage microorganisms under conditions that mimic the poultry, meat, and egg processing industries.}, journal = {International journal of food microbiology}, volume = {303}, number = {}, pages = {32-41}, doi = {10.1016/j.ijfoodmicro.2019.04.012}, pmid = {31129476}, issn = {1879-3460}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Colony Count, Microbial ; Eggs/*microbiology ; *Food Microbiology ; *Food-Processing Industry ; Kinetics ; Meat/*microbiology ; Poultry ; Stainless Steel ; }, abstract = {Pathogens and spoilage microorganisms can develop multispecies biofilms on food contact surfaces; however, few studies have been focused on evaluated mixed biofilms of these microorganisms. Therefore this study investigated the biofilm development by pathogenic (Bacillus cereus, Escherichia coli, Listeria monocytogenes, and Salmonella enterica Enteritidis and Typhimurium serotypes) and spoilage (Bacillus cereus and Pseudomonas aeruginosa) microorganisms onto stainless-steel (SS) and polypropylene B (PP) coupons; under conditions that mimic the dairy, meat, and egg processing industry. Biofilms were developed in TSB with 10% chicken egg yolk (TSB + EY), TSB with 10% meat extract (TSB + ME) and whole milk (WM) onto SS and PP. Each tube was inoculated with 25 μL of each bacteria and then incubated at 9 or 25 °C, with enumeration at 1, 48, 120, 180 and 240 h. Biofilms were visualized by epifluorescence and scanning electron microscopy (SEM). Biofilm development occurred at different phases, depending on the incubation conditions. In the reversible adhesion, the cell density of each bacteria was between 1.43 and 6.08 Log10 CFU/cm[2] (p < 0.05). Moreover, significant reductions in bacteria appeared at 9 °C between 1 and 48 h of incubation. Additionally, the constant multiplication of bacteria in the biofilm occurred at 25 °C between 48 and 180 h of incubation, with increments of 2.08 Log10 CFU/cm[2] to S. Typhimurium. Population establishment was observed between 48 and 180 h and 180-240 h incubation, depending on the environmental conditions (25 and 9 °C, respectively). For example, in TSB + ME at 25 °C, S. Typhimurium, P aeruginosa, and L. monocytogenes showed no statistical differences in the amounts between 48 and 180 h incubation. The dispersion phase was identified for L. monocytogenes and B. cereus at 25 °C. Epifluorescence microscopy and SEM allowed visualizing the bacteria and extracellular polymeric substances at the different biofilm stages. In conclusion, pathogens and spoilage microorganisms developed monospecies with higher cellular densities than multiespecies biofilms. In multispecies biofilms, the time to reach each biofilm phase varied is depending on environmental factors. Cell count decrements of 1.12-2.44 Log10 CFU/cm[2] occurred at 48 and 240 h and were most notable in the biofilms developed at 9 °C. Additionally, cell density reached by each microorganism was different, P. aeruginosa and Salmonella were the dominant microorganisms in the biofilms while B. cereus showed the lower densities until undetectable levels.}, } @article {pmid31129376, year = {2019}, author = {Meng, Y and Zhou, Z and Meng, F}, title = {Impacts of diel temperature variations on nitrogen removal and metacommunity of anammox biofilm reactors.}, journal = {Water research}, volume = {160}, number = {}, pages = {1-9}, doi = {10.1016/j.watres.2019.05.021}, pmid = {31129376}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; *Denitrification ; Ecosystem ; *Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; Temperature ; }, abstract = {The influence of diel temperature variations (DTVs) on nitrogen removal and bacterial communities was investigated in two parallel anammox reactors (i.e., control and DTV reactors). The control reactor was operated at a constant temperature of 30 °C, whereas the DTV reactor was operated in a temperature fluctuation mode with a cycle of 12/12 h of high/low temperatures. Nine water temperature variations for the day/night periods were set from 30/30 °C (i.e., Δ0 °C) to 38/22 °C (i.e., Δ16 °C). An increase in DTVs from Δ8 °C (34/26 °C) to Δ16 °C (38/22 °C) caused a significant decline in reactor performance and a shift in bacterial diversity. Compared to the control reactor, for instance, nitrogen removal efficiency decreased (P < 0.05) when temperature fluctuations exceeded Δ8 °C in the DTV reactor with a decreasing ΔNO3[-]/ΔNH4[+] ratio (from 0.21 ± 0.15 to 0.16 ± 0.04). The results of 16S rRNA gene sequencing showed that the initial disturbance of temperature variations led to increased levels of bacterial diversity (i.e., alpha diversity) and decreased community levels of anammox consortia whereas they slightly recovered at the end of each DTV phase. Notably, Candidatus Jettenia was more sensitive to strong water temperature fluctuations, with the lower relative abundance at Δ14 °C (17.11 ± 5.01%) and Δ16 °C (17.83 ± 7.22%) than at Δ4 °C (39.82 ± 0.01%). In contrast, Ca. Brocadia and Ca. Kuenenia had higher relative abundance at Δ14 °C (i.e., 0.24 ± 0.07% and 0.09 ± 0.02%, respectively) and Δ16 °C (i.e., 0.28 ± 0.05% and 0.12 ± 0.03%, respectively) compared to that at Δ4 °C (i.e., 0.15 ± 0.04% and 0.04 ± 0.01%, respectively). Nitrifiers (i.e., unidentified_Nitrospiraceae and Nitrosomonas) and denitrifiers (i.e., Denitratisoma) were also capable of tolerating high temperature perturbations. Overall this study furthers our knowledge of responses of the microbial ecology of anammox bacteria to DTVs in anammox processes, which could aid us in optimizing anammox-related wastewater treatment systems and in understanding the nitrogen cycles of natural ecosystems.}, } @article {pmid31129309, year = {2019}, author = {Lin, H and Liu, X and Shen, Z and Cheng, W and Zeng, Z and Chen, Y and Tang, C and Jiang, T}, title = {The effect of isoflavaspidic acid PB extracted from Dryopteris fragrans (L.) Schott on planktonic and biofilm growth of dermatophytes and the possible mechanism of antibiofilm.}, journal = {Journal of ethnopharmacology}, volume = {241}, number = {}, pages = {111956}, doi = {10.1016/j.jep.2019.111956}, pmid = {31129309}, issn = {1872-7573}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects/growth & development ; *Dryopteris ; Ergosterol/metabolism ; Microbial Sensitivity Tests ; Phloroglucinol/*analogs & derivatives/*pharmacology ; Trichophyton/*drug effects/physiology ; }, abstract = {Dryopteris fragrans (L.) Schott (D. fragrans), a deciduous perennial herb, has been traditionally used for treatment of various skin diseases in Heilongjiang province of China for many years. Phloroglucinol derivatives extracted from D. fragrans were the most effective fraction against dermatophytes. Isoflavaspidic acid PB is a typically phloroglucinol derivative which extracted from D. fragrans and has been reported to exert anti-fungal activities against several dermatophytes.

AIM OF THE STUDY: This study aimed to evaluate anti-fungal and anti-biofilm activity of isoflavaspidic acid PB on planktonic and biofilm growth of dermatophytes and explore possible mechanisms of anti-biofilm.

MATERIALS AND METHODS: Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of isoflavaspidic acid PB against 25 isolates of dermatophytes were determined by the Clinical and Laboratory Standards Institute (CLSI) M38-A2 method. The effects of isoflavaspidic acid PB on dermatophytes biofilm formation and pre-formed biofilm were assessed by 2.3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[carbonyl (phenylamino)]-2H-tetrazolium hydroxide (XTT) assay. Morphology of mature biofilm were observed by Scanning Electron Microscope (SEM). Biomass, exopolysaccharide and ergosterol content of mature biofilm were analyzed by gravimetric analysis, anthranone sulfuric acid method and Ultra Performance Liquid Chromatography (UPLC) assay respectively.

RESULT: The MIC and MFC ranges of isoflavaspidic acid PB against 25 isolates of dermatophytes were 20-80 μg/mL and 40-80 μg/mL respectively. Isoflavaspidic acid PB (2 MIC) inhibited not only Trichophyton biofilm formation (54.8% ∼ 81.2%) but also the metabolic activity of mature biofilm (20.7% ∼ 44.2%). The result of SEM showed that isoflavaspidic acid PB (8 MIC) could destroy the morphology of hyphae seriously. Comparing with control group, biomass, exopolysaccharide and ergosterol content of the mature biofilm under isoflavaspidic acid PB (8 MIC) were significantly decreased (P < 0.01).

CONCLUSION: Isoflavaspidic acid PB had anti-fungal and fungicidal activities against dermatophytes. Isoflavaspidic acid PB could inhibit the biofilm of Trichophyton. The mechanism might be related to the decline of the biofilm biomass, exopolysaccharide and ergosterol content. These results showed that isoflavaspidic acid PB could be explored for promising anti-biofilm drugs.}, } @article {pmid31128369, year = {2019}, author = {Taşkan, B and Casey, E and Hasar, H}, title = {Simultaneous oxidation of ammonium and tetracycline in a membrane aerated biofilm reactor.}, journal = {The Science of the total environment}, volume = {682}, number = {}, pages = {553-560}, doi = {10.1016/j.scitotenv.2019.05.111}, pmid = {31128369}, issn = {1879-1026}, mesh = {Ammonium Compounds/*chemistry ; Biofilms ; Bioreactors ; Membranes, Artificial ; Oxidation-Reduction ; Tetracycline/*chemistry ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*chemistry ; }, abstract = {The membrane aerated biofilms reactor (MABR) is an emerging technology in wastewater treatment with particular advantages including high rate nitrification, and very high oxygen transfer efficiencies. In this study a synthetic feed water incorporating tetracycline (TC) was investigated in a MABR. Simultaneous removal of ammonium and tetracycline (TC) in the reactor, formation of TC transformation products (TPs), and microbial community analysis in the biofilm growing on the membrane were performed. A range of TC and ammonium loading rates and the effect of different intra-membrane oxygen pressures were on treatment performance were systematically investigated. Successful nitrification and TC degradation were achieved with the highest TC removal (63%) obtained at a HRT of 18 h HRT and 0.41 bar gas pressure. It has shown that different operating conditions (HRT and gas pressure) do not cause a significant change in ammonium removal. The concentration of TPs such as ETC, EATC, and ATC was determined to be at the ppb level. Molecular results showed that MABR reactor was mainly dominated by β-proteobacteria. The relative abundance of this group decreased in parallel with the increasing ammonium and TC loading.}, } @article {pmid31125769, year = {2019}, author = {Peeridogaheh, H and Pourhajibagher, M and Barikani, HR and Bahador, A}, title = {The impact of Aggregatibacter actinomycetemcomitans biofilm-derived effectors following antimicrobial photodynamic therapy on cytokine production in human gingival fibroblasts.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {1-6}, doi = {10.1016/j.pdpdt.2019.05.025}, pmid = {31125769}, issn = {1873-1597}, mesh = {Aggregatibacter actinomycetemcomitans/*drug effects ; Biofilms/*drug effects ; Cytokines/*drug effects ; Dose-Response Relationship, Drug ; Fibroblasts/*drug effects ; Gingiva/*drug effects ; Humans ; Indocyanine Green/pharmacology ; Lasers, Semiconductor ; Peri-Implantitis/drug therapy ; Periodontitis/drug therapy ; Photochemotherapy/*methods ; Photosensitizing Agents/pharmacology ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (aPDT) is an effective adjunctive therapeutic modality for the treatment of local infections, including periodontitis and peri-implantitis. After receiving aPDT, microbial cells in the biofilm structure may produce and/ or release soluble biofilm-derived effectors (BDEs), which may affect the biology of the host cells in the community context of their surrounding microenvironment. Given the fact that no study has investigated the role of BDEs following aPDT in the pathogenesis of infectious diseases, the aim of the current study was to determine the effect of BDEs of Aggregatibacter actinomycetemcomitans following exposure to sub-lethal doses of indocyanine green (ICG)-aPDT on human gingival fibroblasts (HGFs) in terms of cytokines produced.

MATERIALS AND METHODS: In this study, we evaluated the effect of biofilm-conditioned medium (BCM) resulting from the treatment of A. actinomycetemcomitans biofilm with a sub-lethal dose of aPDT on cytokines production, including IL-6, IL-8, CXCL10, TGF-β, and bFGF of HGFs using enzyme-linked immunoassays (ELISA). The sensitivity of cytokines to BDEs was determined by micro-titer plates.

RESULTS: The maximal sub-lethal dose of ICG-PDT was 20.15 μM/mL ICG at a fluence of 31.2 J/cm[2]. The BCM of ICG-PDT-treated viable A. actinomycetemcomitans significantly reduced IL-6, IL-8, and CXCL10 levels compared to the BCM of untreated viable A. actinomycetemcomitans (78-, 93-, and 61.6-fold reduction, respectively; all P < 0.01). TGF-β and bFGF were strongly induced by BCM of ICG-PDT treated viable A. actinomycetemcomitans (by 57.7 and 36.1 folds, respectively; both P < 0.05). The BCM of untreated viable A. actinomycetemcomitans degraded most of the CxCL10, TGF-β and bFGF (58.8, 61.5, and 71.6%, respectively) in 24 h, while it degraded 9.3% of IL-6 and 15.1% of IL-8 after 24 h.

CONCLUSION: The results of the current study revealed that a sub-lethal dose of ICG-aPDT through the effect of BCM on HGFs could not only significantly reduce the production of pro-inflammatory cytokines but also promoted their role in periodontal regeneration due to increasing the bFGF level. Altogether, ICG-aPDT, with it's antimicrobial effects reduces inflammation and induces of tissue regeneration resulting from BCM, can be considered an efficient adjunctive therapeutic method for the treatment of local infections.}, } @article {pmid31124069, year = {2019}, author = {Singhal, N and Singh, NS and Maurya, AK and Virdi, JS}, title = {Virulence-associated traits and in vitro biofilm-forming ability of Escherichia coli isolated from a major river traversing Northern India.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {21}, pages = {21304-21311}, pmid = {31124069}, issn = {1614-7499}, mesh = {Biofilms ; *Environmental Monitoring ; Escherichia coli/genetics/isolation & purification/*physiology ; Escherichia coli Proteins/genetics ; Humans ; India ; Phenotype ; Phylogeny ; Rivers/*microbiology ; Virulence/genetics ; Virulence Factors/genetics ; beta-Lactamases/genetics ; }, abstract = {Several strains of Escherichia coli harbor virulence traits, resulting in E. coli-related intestinal and extra-intestinal infections. Various studies have reported that extra-intestinal pathogenic E. coli (ExPEC) strains were prevalent in nonhuman reservoirs, including environmental waterways. It is therefore important to identify the pathogenic potential and/or ExPEC status of E. coli strains inhabiting the aquatic environments associated with anthropogenic activities. Besides virulence-associated genes, biofilm production also helps in the survival of E. coli in environmental waterbodies. Thus, the aim of the current study was to assess the virulence potential, ExPEC status, and biofilm-producing capability of E. coli isolated from the River Yamuna, a major river traversing the National Capital Region of Delhi, India. We also tried to discern a co-relation, if any, between virulence, biofilm formation, and antimicrobial resistance in these strains. Our results indicated that virulence-associated genes were scarce and none of the strain qualified the molecular criteria essential for ExPEC. This suggested that E. coli strains which can presumably cause human extra-intestinal infections were not prominent in the River Yamuna. However, the fact that more than 80% of the aquatic E. coli isolates were moderate and strong biofilm producers suggests that E. coli in these environments might serve as opportunistic pathogens. Also, no unequivocal association was observed between biofilm production, virulence, and β-lactamase genes in E. coli strains. As per the best of our knowledge, this is the first study where the relationship between virulence, biofilms, and antimicrobials has been examined in E. coli, isolated from an Indian urban aquatic waterbody.}, } @article {pmid31120391, year = {2019}, author = {Zhou, X and Li, M and Xu, L and Shi, C and Shi, X}, title = {Characterization of Antibiotic Resistance Genes, Plasmids, Biofilm Formation, and In Vitro Invasion Capacity of Salmonella Enteritidis Isolates from Children with Gastroenteritis.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {8}, pages = {1191-1198}, doi = {10.1089/mdr.2018.0421}, pmid = {31120391}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms/drug effects/*growth & development ; Caco-2 Cells ; Cell Line, Tumor ; Child ; Drug Resistance, Multiple, Bacterial/*genetics ; Epithelial Cells/microbiology ; Gastroenteritis/drug therapy/*microbiology ; Humans ; Microbial Sensitivity Tests/methods ; Plasmids/*genetics ; Quinolones/therapeutic use ; Salmonella Infections/drug therapy/*microbiology ; Salmonella enteritidis/drug effects/*genetics/*growth & development ; beta-Lactamases/genetics ; }, abstract = {Objectives: The primary aim of this study was to investigate the presence of antibiotic resistance genes (ARGs) and plasmid replicon types for 75 multidrug-resistant (MDR) Salmonella Enteritidis isolates from children with gastroenteritis. We also evaluated the association among biofilm formation, in vitro invasion capacity, and antibiotic resistance phenotypes. Materials and Methods: Twenty-two ARGs and 18 different plasmid incompatibility types were investigated using polymerase chain reaction (PCR) and DNA sequencing. In vitro invasion capacity of S. Enteritidis isolates possessing different antibiotic resistance patterns was assessed using the Caco2 human intestinal epithelial cell line and biofilm formation was performed in a 96-well polystyrene well format using crystal violet detection. Results: The presence of plasmid-mediated quinolone resistance genes and β-lactamase genes was established using PCR amplification. All the tested S. Enteritidis isolates that were fluoroquinolone resistant possessed gyrA mutations and 50% also possessed mutations in parC. MDR S. Enteritidis isolates containing three (29/75) or four (21/75) plasmid replicon types were predominant and 71/75 carried both FIIs and FIC replicon-type plasmids. MDR isolates were strong or moderate biofilm producers and a significant positive association (p < 0.05) between antibiotic resistance and biomass of biofilms was observed in the strains assayed. A ceftiofur-resistant strain was significantly more invasive (p < 0.01) than the other isolates. Conclusions: We observed a high incidence of ARGs and diversity of plasmids in S. Enteritidis isolates from children. Biofilm formation and invasion capacity highlight a significant hazard to public health.}, } @article {pmid31120377, year = {2020}, author = {Cowle, MW and Webster, G and Babatunde, AO and Bockelmann-Evans, BN and Weightman, AJ}, title = {Impact of flow hydrodynamics and pipe material properties on biofilm development within drinking water systems.}, journal = {Environmental technology}, volume = {41}, number = {28}, pages = {3732-3744}, doi = {10.1080/09593330.2019.1619844}, pmid = {31120377}, issn = {1479-487X}, mesh = {Bacteria ; Biofilms ; *Drinking Water ; Hydrodynamics ; Water Microbiology ; Water Supply ; }, abstract = {The aim of this study was to investigate the combined impact of flow hydrodynamics and pipe material on biofilm development in drinking water distribution systems (DWDS). Biofilms were formed on four commonly used pipe materials (namely polyvinyl chloride, polypropylene, structured wall high-density polyethylene and solid wall high-density polyethylene) within a series of purpose built flow cell reactors at two different flow regimes. Results indicate that varying amounts of microbial material with different morphologies were present depending on the pipe material and conditioning. The amount of microbial biomass was typically greater for the biofilms conditioned at lower flows. Whereas, biofilm development was inhibited at higher flows indicating shear forces imposed by flow conditions were above the critical levels for biofilm attachment. Alphaproteobacteria was the predominant bacterial group within the biofilms incubated at low flow and represented 48% of evaluated phylotypes; whilst at higher flows, Betaproteobacteria (45%) and Gammaproteobacteria (33%) were the dominant groups. The opportunistic pathogens, Sphingomonas and Pseudomonas were found to be particularly abundant in biofilms incubated at lower flows, and only found within biofilms incubated at higher flows on the rougher materials assessed. This suggests that these bacteria have limited ability to propagate within biofilms under high shear conditions without sufficient protection (roughness). These findings expand on knowledge relating to the impact of surface roughness and flow hydrodynamics on biofilm development within DWDS.}, } @article {pmid31119950, year = {2019}, author = {Irankhah, S and Abdi Ali, A and Mallavarapu, M and Soudi, MR and Subashchandrabose, S and Gharavi, S and Ayati, B}, title = {Ecological role of Acinetobacter calcoaceticus GSN3 in natural biofilm formation and its advantages in bioremediation.}, journal = {Biofouling}, volume = {35}, number = {4}, pages = {377-391}, doi = {10.1080/08927014.2019.1597061}, pmid = {31119950}, issn = {1029-2454}, mesh = {Acinetobacter calcoaceticus/*physiology ; Biodegradation, Environmental ; *Biofilms ; Ecosystem ; Green Fluorescent Proteins/metabolism ; Phenols/metabolism ; Sewage ; }, abstract = {This study assessed the role of a new Acinetobacter calcoaceticus strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3-gfp strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07 × 10[7] more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3-gfp in R2 were unable to increase the efficiency as much as measured in R3. The presence of GSN3-gfp in R3 conveyed advantages, including enhancement of cell immobilization, population diversity, metabolic cooperation and ultimately treatment efficiency.}, } @article {pmid31118922, year = {2019}, author = {Zhang, M and Zhang, X and Tong, L and Ou, D and Wang, Y and Zhang, J and Wu, Q and Ye, Y}, title = {Random Mutagenesis Applied to Reveal Factors Involved in Oxidative Tolerance and Biofilm Formation in Foodborne Cronobacter malonaticus.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {877}, pmid = {31118922}, issn = {1664-302X}, abstract = {Cronobacter species are linked with life-treating diseases in neonates and show strong tolerances to environmental stress. However, the information about factors involved in oxidative tolerance in Cronobacter remains elusive. Here, factors involved in oxidative tolerance in C. malonaticus were identified using a transposon mutagenesis. Eight mutants were successfully screened based on a comparison of the growth of strains from mutant library (n = 215) and wild type (WT) strain under 1.0 mM H2O2. Mutating sites including thioredoxin 2, glutaredoxin 3, pantothenate kinase, serine/threonine protein kinase, pyruvate kinase, phospholipase A, ferrous iron transport protein A, and alanine racemase 2 were successfully identified by arbitrary PCR and sequencing alignment. Furthermore, the comparison about quantity and structure of biofilms formation among eight mutants and WT was determined using crystal violet staining (CVS), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Results showed that the biofilms of eight mutants significantly decreased within 48 h compared to that of WT, suggesting that mutating genes play important roles in biofilm formation under oxidative stress. The findings provide valuable information for deeply understanding molecular mechanism about oxidative tolerance of C. malonaticus.}, } @article {pmid31118702, year = {2019}, author = {Shrestha, LB and Baral, R and Khanal, B}, title = {Comparative study of antimicrobial resistance and biofilm formation among Gram-positive uropathogens isolated from community-acquired urinary tract infections and catheter-associated urinary tract infections.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {957-963}, pmid = {31118702}, issn = {1178-6973}, abstract = {Background: Gram-positive cocci have emerged to be an important cause of urinary tract infection (UTI) both in community-acquired UTI (Com-UTI) and catheter-associated urinary tract infection (CA-UTI). The objective of this study was to investigate the frequency of Gram-positive cocci urinary tract infections, their susceptibility patterns to commonly used antimicrobial agents and the biofilm forming property with respect to catheter-associated UTI and community-acquired UTI. Methods: A total of 1,360 urine samples from indwelling catheter and 10,423 from mid-stream urine were obtained during a 6-month period and processed following standard microbiological guidelines. Biofilm formation was detected using congo red agar (CRA), tube method (TM) and tissue culture plate (TCP) method. Chi-square test and independent sample t-test were employed to calculate the significance. Statistical significance was set at P-value ≤0.05. Results: The infection rate was significantly higher in CA-UTI as compared to Com-UTI (25% vs 18%, p=0.0001). Among 2,216 organisms isolated, 471 were Gram-positive cocci; 401 were obtained from Com-UTI while 70 were from CA-UTI. Enterococcus faecalis was the most common organism isolated from Com-UTI, while Staphylococcus aureus was commonest among CA-UTI. Multi-drug resistance, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci were also significantly higher in CA-UTI as compared to Com-UTI. Biofilm-forming property was significantly higher in CA-UTI than Com-UTI. The sensitivity of congo red agar method and tube method was 79% and 81.9% respectively and specificity was 98.5% each. Antimicrobial resistance was significantly higher in biofilm-formers as compared to non-formers. Conclusion: Gram-positive bacteria are a significant cause of both CA-UTI and Com-UTI with Enterococcus faecalis and Staphylococcus aureus as common pathogen. Biofilm formation and multi-drug resistance is significantly higher in CA-UTI than Com-UTI. Routine surveillance of antimicrobial resistance and biofilm formation is necessary in all cases of UTI to ensure the proper management of patients.}, } @article {pmid31118466, year = {2019}, author = {Dettweiler, M and Lyles, JT and Nelson, K and Dale, B and Reddinger, RM and Zurawski, DV and Quave, CL}, title = {American Civil War plant medicines inhibit growth, biofilm formation, and quorum sensing by multidrug-resistant bacteria.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {7692}, pmid = {31118466}, issn = {2045-2322}, support = {R01 AT007052/AT/NCCIH NIH HHS/United States ; R21 AI136563/AI/NIAID NIH HHS/United States ; 52006923/HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {*American Civil War ; Anti-Infective Agents, Local/isolation & purification/*pharmacology/toxicity ; Aralia/*chemistry ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects/physiology ; Herbal Medicine/*history ; History, 19th Century ; Humans ; Keratinocytes/drug effects ; Liriodendron/*chemistry ; Military Medicine/*history ; Molecular Structure ; Phytotherapy ; Plant Extracts/*pharmacology/toxicity ; Plants, Medicinal/*chemistry ; Quercus/*chemistry ; Quorum Sensing/*drug effects ; Species Specificity ; Wound Infection/drug therapy ; }, abstract = {A shortage of conventional medicine during the American Civil War (1861-1865) spurred Confederate physicians to use preparations of native plants as medicines. In 1863, botanist Francis Porcher compiled a book of medicinal plants native to the southern United States, including plants used in Native American traditional medicine. In this study, we consulted Porcher's book and collected samples from three species that were indicated for the formulation of antiseptics: Liriodendron tulipifera, Aralia spinosa, and Quercus alba. Extracts of these species were tested for the ability to inhibit growth in three species of multidrug-resistant pathogenic bacteria associated with wound infections: Staphylococcus aureus, Klebsiella pneumoniae, and Acinetobacter baumannii. Extracts were also tested for biofilm and quorum sensing inhibition against S. aureus. Q. alba extracts inhibited growth in all three species of bacteria (IC50 64, 32, and 32 µg/mL, respectively), and inhibited biofilm formation (IC50 1 µg/mL) in S. aureus. L. tulipifera extracts inhibited biofilm formation (IC50 32 µg/mL) in S. aureus. A. spinosa extracts inhibited biofilm formation (IC50 2 µg/mL) and quorum sensing (IC50 8 µg/mL) in S. aureus. These results support that this selection of plants exhibited some antiseptic properties in the prevention and management of wound infections during the conflict.}, } @article {pmid31117281, year = {2019}, author = {Rajkowska, K and Nowicka-Krawczyk, P and Kunicka-Styczyńska, A}, title = {Effect of Clove and Thyme Essential Oils on Candida Biofilm Formation and the Oil Distribution in Yeast Cells.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {10}, pages = {}, pmid = {31117281}, issn = {1420-3049}, mesh = {Antifungal Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects/pathogenicity ; Cell Wall/drug effects ; Clove Oil/chemistry/pharmacology ; Microbial Sensitivity Tests ; Oils, Volatile/chemistry/*pharmacology ; Plant Oils/chemistry/pharmacology ; Syzygium/*chemistry ; Thymus Plant/*chemistry ; }, abstract = {Candida biofilm structure is particularly difficult to eradicate, since biofilm is much more resistant to antifungal agents than planktonic cells. In this context, a more effective strategy seems to be the prevention of biofilm formation than its eradication. The aim of the study was to examine whether the process of initial colonization of materials (glass, polyethylene terephthalate, polypropylene) by food-borne Candida sp. can be impeded by clove and thyme essential oils, used at their minimal inhibitory concentrations. In the presence of clove oil, 68.4-84.2% of the yeast tested showed a statistically significant reduction in biofilm formation, depending on the material. After treatment with thyme oil, statistically significant decrease in biofilm cell numbers was observed for 63.2-73.7% of yeasts. Confocal laser scanning microscopy showed diverse compounds of clove and thyme oils that were disparately located in C. albicans cell, on a cell wall and a cell membrane, in cytoplasm, and in vacuoles, depicting the multidirectional action of essential oils. However, essential oils that were used in sub-inhibitory concentration were sequestrated in the yeast vacuoles, which indicate the activation of Candida defense mechanisms by cell detoxification. Clove and thyme essential oils due to their anti-biofilm activity can be efficiently used in the prevention of the tested abiotic surfaces colonization by Candida sp.}, } @article {pmid31117001, year = {2019}, author = {Huang, TC and Chen, CJ and Chen, CC and Ding, SJ}, title = {Enhancing osteoblast functions on biofilm-contaminated titanium alloy by concentration-dependent use of methylene blue-mediated antimicrobial photodynamic therapy.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {27}, number = {}, pages = {7-18}, doi = {10.1016/j.pdpdt.2019.05.021}, pmid = {31117001}, issn = {1873-1597}, mesh = {Aggregatibacter actinomycetemcomitans/drug effects ; Alloys ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Lasers, Semiconductor ; Methylene Blue/administration & dosage/*pharmacology ; Osteoblasts/*drug effects ; Peri-Implantitis/drug therapy ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Streptococcus mutans/drug effects ; *Titanium ; }, abstract = {The concentration of methylene blue (MB) photosensitizer could affect the eradication efficacy of antimicrobial photodynamic therapy (aPDT) in the treatment of contaminated implants, which is linked to the osseointegration of the implant. We evaluated osteoblast functions on the contaminated SLA (sandblasting, large-grit and acid-etching) Ti alloy surfaces after the concentration-dependent use of MB-aPDT. Totally 1164 SLA discs were randomly distributed for the analyses of antibacterial efficacy and osteoblast functions. Gram-negative (Aggregatibacter actinomycetemcomitans; A. actinomycetemcomitans) or Gram-positive (Streptococcus mutans; S. mutans) adhered on disc samples was subjected to aPDT with different MB concentrations (200, 250, 300, 350, and 400 μg/mL) using 660 nm diode laser with maximum output 80 mW for 1 min irradiation (4.8 J/cm[2]). Bactericidal effect was examined by viability, morphology, and lipopolysaccharide (LPS) assays. The disinfected disc surfaces by MB-aPDT to support osteoblast-like MG63 attachment, proliferation, differentiation, and mineralization were assessed for the predetermined culture time intervals. The statistical differences between the means were performed using a one-way analysis of variance (ANOVA) with a post hoc Scheffe test. The results of the morphology observation and bacterial survival examination consistently indicated a remarkably lower quantity of bacterial colonies on biofilm-contaminated surfaces after the aPDT treatment with higher MB concentration. Similarly, the higher MB concentration in aPDT resulted in the lower LPS amounts remaining on the A. actinomycetemcomitans-contaminated surfaces. Intriguingly, the expression of osteoblast cultured on disinfected surfaces using aPDT with higher MB concentration was comparable to the control without contamination. Within the limits of this in vitro model, this formulation of 400 μg/mL MB used in aPDT may be not only the lethal concentration against the 2 bacteria-contaminated implants, but it could also enhance the osteoblast functions on the contaminated implants. Nevertheless, the efficacy in the clinical practice for peri-implantitis therapy remains to be studied.}, } @article {pmid31116790, year = {2019}, author = {Feng, R and Zhao, G and Yang, Y and Xu, M and Huang, S and Sun, G and Guo, J and Li, J}, title = {Enhanced biological removal of intermittent VOCs and deciphering the roles of sodium alginate and polyvinyl alcohol in biofilm formation.}, journal = {PloS one}, volume = {14}, number = {5}, pages = {e0217401}, pmid = {31116790}, issn = {1932-6203}, mesh = {Alginates ; *Biodegradation, Environmental ; *Biofilms/growth & development ; Filtration ; Microbial Consortia/genetics/physiology ; Polyvinyl Alcohol ; RNA, Ribosomal, 16S/genetics ; Volatile Organic Compounds/*isolation & purification ; }, abstract = {Developing a robust biofilm is a prerequisite for a biotrickling filter to obtain the good performance in removing volatile organic compounds (VOCs). But the biofilm formation can be seriously disturbed under intermittent loading condition due to carbon starvation stress in idle time. In this study, a biotrickling filter, with its packing materials being modified by 3% sodium alginate and 5% polyvinyl alcohol (v/v = 1:3), was employed to treat intermittent VOCs. Results showed that the removal efficiencies of toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene was significantly enhanced in the BTF compared to the control one. Under relatively lower inlet loading, nearly complete removal of the five pollutants was achieved. A quantitative analysis showed that the concentration of total organic compound (TOC) in the leachate maintained at a high level, and had a strongly positive correlation with the divergence of microbial communities. The capacity of biofilm formation in the BTF was approximately four-fold higher than the control BTF, while the quantity of EPS secreted was more than ten-fold. EPS comprised largely of protein, and to less extent, polysaccharide. The biofilm formed on the modified packing materials maintained higher levels of microbial diversity and stability, even when modifiers were complete depleted or the VOCs inlet loading was increased. This study highlights the importance of packing materials for reducing the gap in performance between laboratory and industrial applications of BTFs.}, } @article {pmid31116789, year = {2019}, author = {Huang, MY and Woolford, CA and May, G and McManus, CJ and Mitchell, AP}, title = {Circuit diversification in a biofilm regulatory network.}, journal = {PLoS pathogens}, volume = {15}, number = {5}, pages = {e1007787}, pmid = {31116789}, issn = {1553-7374}, support = {R21 AI135178/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*classification/*growth & development ; Candida albicans/*classification/genetics ; Candidiasis/*genetics/virology ; Fungal Proteins/*genetics ; *Gene Expression Regulation, Fungal ; Genetic Association Studies ; Genetic Speciation ; Humans ; Hyphae/*genetics/growth & development ; Signal Transduction ; Transcription Factors ; }, abstract = {Genotype-phenotype relationships can vary extensively among members of a species. One cause of this variation is circuit diversification, the alteration of gene regulatory relationships among members of a species. Circuit diversification is thought to be a starting point for the circuit divergence or rewiring that occurs during speciation. How widespread is circuit diversification? Here we address this question with the fungal pathogen Candida albicans, which forms biofilms rich in distinctive hyphal cells as a prelude to infection. Our understanding of the biofilm/hyphal regulatory network comes primarily from studies of one clinical isolate, strain SC5314, and its marked derivatives. We used CRISPR-based methods to create mutations of four key biofilm transcription factor genes-BCR1, UME6, BRG1, and EFG1 -in SC5314 and four additional clinical isolates. Phenotypic analysis revealed that mutations in BCR1 or UME6 have variable impact across strains, while mutations in BRG1 or EFG1 had uniformly severe impact. Gene expression, sampled with Nanostring probes and examined comprehensively for EFG1 via RNA-Seq, indicates that regulatory relationships are highly variable among isolates. Our results suggest that genotype-phenotype relationships vary in this strain panel in part because of differences in control of BRG1 by BCR1, a hypothesis that is supported through engineered constitutive expression of BRG1. Overall, the data show that circuit diversification is the rule, not the exception, in this biofilm/hyphal regulatory network.}, } @article {pmid31116437, year = {2019}, author = {Abbondante, S and Pearlman, E}, title = {Breaching bacterial biofilm with neutrophil α-mannosidase.}, journal = {Journal of leukocyte biology}, volume = {105}, number = {6}, pages = {1085}, doi = {10.1002/JLB.4CE0419-139R}, pmid = {31116437}, issn = {1938-3673}, mesh = {Bacteria ; Biofilms ; Humans ; *Infections ; *Neutrophils ; alpha-Mannosidase ; }, } @article {pmid31116394, year = {2020}, author = {Laulund, ASB and Trøstrup, H and Lerche, CJ and Thomsen, K and Christophersen, L and Calum, H and Høiby, N and Moser, C}, title = {Synergistic effect of immunomodulatory S100A8/A9 and ciprofloxacin against Pseudomonas aeruginosa biofilm in a murine chronic wound model.}, journal = {Pathogens and disease}, volume = {78}, number = {5}, pages = {}, doi = {10.1093/femspd/ftz027}, pmid = {31116394}, issn = {2049-632X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Calgranulin A/*physiology ; Chronic Disease ; Ciprofloxacin/*pharmacology ; Colony Count, Microbial ; Cytokines/metabolism ; Disease Models, Animal ; Drug Synergism ; Female ; Host-Pathogen Interactions ; Intercellular Signaling Peptides and Proteins/metabolism ; Mice ; Mice, Inbred BALB C ; Pseudomonas Infections/immunology/microbiology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Wound Infection/*immunology/*microbiology ; }, abstract = {UNLABELLED: The majority of chronic wounds are associated with bacterial biofilms recalcitrant to antibiotics and host responses. Immunomodulatory S100A8/A9 is suppressed in Pseudomonas aeruginosa biofilm infected wounds. We aimed at investigating a possible additive effect between S100A8/A9 and ciprofloxacin against biofilms.

MATERIALS/METHODS: Thirty-two mice were injected with alginate-embedded P. aeruginosa following a third-degree burn. The mice were randomized into four groups receiving combination ciprofloxacin and S100A8/A9 or monotherapy ciprofloxacin, S100A8/A9 or a placebo and evaluated by host responses and quantitative bacteriology in wounds. In addition, in vitro checkerboard analysis was performed, with P. aeruginosa and ascending S100A8/A9 and ciprofloxacin concentrations.

RESULTS: S100A8/A9 augmented the effect of ciprofloxacin in vivo by lowering the bacterial quantity compared to the placebo arm and the two monointervention groups (P < 0.0001). S100A8 and 100A9 were increased in the double-treated group as compared to the monointervention groups (P = 0.032, P = 0.0023). Tissue inhibitor of metalloproteinases-1 and keratinocyte\chemokine chemoattractant-1 were increased in the double-intervention group compared to the S100A8/A9 group (P = 0.050, P = 0.050). No in vitro synergism was detected.

CONCLUSION: The observed ciprofloxacin-augmenting effect of S100A8/A9 in vivo was not confirmed by checkerboard analysis, indicating dependence on host cells for the S100A8/A9 effect. S100A8/A9 and ciprofloxacin is a promising therapy for optimizing chronic wound treatment.}, } @article {pmid31115692, year = {2020}, author = {Daood, U and Burrow, MF and Yiu, CKY}, title = {Effect of a novel quaternary ammonium silane cavity disinfectant on cariogenic biofilm formation.}, journal = {Clinical oral investigations}, volume = {24}, number = {2}, pages = {649-661}, pmid = {31115692}, issn = {1436-3771}, mesh = {Ammonium Compounds ; *Biofilms ; *Dental Caries ; *Disinfectants ; Humans ; Silanes ; Streptococcus mutans ; }, abstract = {OBJECTIVE: Evaluate effect of quaternary ammonium silane (QAS) cavity disinfectant on cariogenic biofilm.

MATERIALS AND METHODS: Single- (Streptococcus mutans or Lactobacillus acidophilus), dual- (Streptococcus mutans/Lactobacillus Acidophilus), and multi-species (Streptococcus mutans, Actinomyces naeslundii, and Streptococcus sanguis) biofilms were grown on acid-etched dentine discs. Biofilms were incubated (120 min/37 °C) and allowed to grow for 3 days anaerobically. Discs (no treatment) served as control (group 1). Groups II, III, IV, and V were then treated with 2% chlorhexidine, and 2%, 5%, and 10% QAS (20 s). Discs were returned to well plates with 300 μL of bacterial suspension and placed in anaerobic incubator at 37 °C and biofilms redeveloped for 4 days. Confocal microscopy, Raman, CFU, and MTT assay were performed.

RESULTS: Raman peaks show shifts at 1450 cm[-1], 1453 cm[-1], 1457 cm[-1], 1460 cm[-1], and 1462 cm[-1] for control, 2% CHX, 2%, 5%, and 10% QAS groups in multi-species biofilms. There was reduction of 484 cm[-1] band in 10% QAS group. CLSM revealed densely clustered green colonies in control group and red confluent QAS-treated biofilms with significantly lower log CFU for single/dual species. Metabolic activities of Streptococcus mutans and Lactobacillus acidophilus decreased with increasing QAS exposure time.

CONCLUSION: Quaternary ammonium silanes possess antimicrobial activities and inhibit growth of cariogenic biofilms.

CLINICAL SIGNIFICANCE: Available data demonstrated use of QAS as potential antibacterial cavity disinfectant in adhesive dentistry. Experimental QAS can effectively eliminate caries-forming bacteria, when used inside a prepared cavity, and can definitely overcome problems associated with present available cavity disinfectants.}, } @article {pmid31114932, year = {2020}, author = {Montazeri, A and Salehzadeh, A and Zamani, H}, title = {Effect of silver nanoparticles conjugated to thiosemicarbazide on biofilm formation and expression of intercellular adhesion molecule genes, icaAD, in Staphylococcus aureus.}, journal = {Folia microbiologica}, volume = {65}, number = {1}, pages = {153-160}, pmid = {31114932}, issn = {1874-9356}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Adhesion Molecules/*genetics ; Genes, Bacterial/genetics ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Semicarbazides/*pharmacology ; Silver/*pharmacology ; Staphylococcus aureus/drug effects/*genetics ; }, abstract = {Biofilm formation is regarded as an important factor in the establishment of infections caused by Staphylococcus aureus. In the present study, phenotypic and molecular assays were used to evaluate antibiofilm potential of thiosemicarbazide (Tsc) conjugated with silver nanoparticles (Ag NPs) and functionalized by glutamic acid (Ag@Glu/Tsc NPs) against methicillin-resistant S. aureus (MRSA). Ag NPs were synthesized using precipitation method and conjugated to Tsc using glutamic acid. The NPs were characterized using SEM and FTIR spectroscopy analyses. Then, antibiofilm potential of the prepared NPs against MRSA strains was evaluated using phenotypic method and their effects on the expression of biofilm-associated genes icaA and icaD. Finally, the genes involved with the synthesis of intercellular adhesion molecules were determined. According to the results, Ag@Glu/Tsc NPs inhibited biofilm formation of MRSA strains up to 76.7% compared with the control. In addition, expression of the biofilm-associated genes icaA and icaD reduced by 66.7% and 60.3%, respectively in the presence of sub-inhibitory concentration of Ag@Glu/Tsc NPs. In conclusion, Ag@Glu/Tsc NPs could be considered as a potent antibacterial agent to inhibit bacterial biofilms.}, } @article {pmid31114399, year = {2019}, author = {Dance, DA and Wuthiekanun, V and Sarovich, D and Price, EP and Limmathurotsakul, D and Currie, BJ and Trung, TT}, title = {Pan-drug-resistant and biofilm-producing strain of Burkholderia pseudomallei: first report of melioidosis from a diabetic patient in Yogyakarta, Indonesia [Letter].}, journal = {International medical case reports journal}, volume = {12}, number = {}, pages = {117-118}, pmid = {31114399}, issn = {1179-142X}, } @article {pmid31113899, year = {2019}, author = {Pisithkul, T and Schroeder, JW and Trujillo, EA and Yeesin, P and Stevenson, DM and Chaiamarit, T and Coon, JJ and Wang, JD and Amador-Noguez, D}, title = {Metabolic Remodeling during Biofilm Development of Bacillus subtilis.}, journal = {mBio}, volume = {10}, number = {3}, pages = {}, pmid = {31113899}, issn = {2150-7511}, support = {P41 GM066326/GM/NIGMS NIH HHS/United States ; P41 GM103399/GM/NIGMS NIH HHS/United States ; P41 GM108538/GM/NIGMS NIH HHS/United States ; R35 GM127088/GM/NIGMS NIH HHS/United States ; }, mesh = {Adaptation, Physiological ; Bacillus subtilis/*growth & development/*metabolism ; Biofilms/*growth & development ; Gene Expression Profiling ; *Metabolism ; Metabolomics ; Proteomics ; }, abstract = {Biofilms are structured communities of tightly associated cells that constitute the predominant state of bacterial growth in natural and human-made environments. Although the core genetic circuitry that controls biofilm formation in model bacteria such as Bacillus subtilis has been well characterized, little is known about the role that metabolism plays in this complex developmental process. Here, we performed a time-resolved analysis of the metabolic changes associated with pellicle biofilm formation and development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. We report surprisingly widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. Most of these metabolic alterations were hitherto unrecognized as biofilm associated. For example, we observed increased activity of the tricarboxylic acid (TCA) cycle during early biofilm growth, a shift from fatty acid biosynthesis to fatty acid degradation, reorganization of iron metabolism and transport, and a switch from acetate to acetoin fermentation. Close agreement between metabolomic, transcriptomic, and proteomic measurements indicated that remodeling of metabolism during biofilm development was largely controlled at the transcriptional level. Our results also provide insights into the transcription factors and regulatory networks involved in this complex metabolic remodeling. Following upon these results, we demonstrated that acetoin production via acetolactate synthase is essential for robust biofilm growth and has the dual role of conserving redox balance and maintaining extracellular pH. This report represents a comprehensive systems-level investigation of the metabolic remodeling occurring during B. subtilis biofilm development that will serve as a useful road map for future studies on biofilm physiology.IMPORTANCE Bacterial biofilms are ubiquitous in natural environments and play an important role in many clinical, industrial, and ecological settings. Although much is known about the transcriptional regulatory networks that control biofilm formation in model bacteria such as Bacillus subtilis, very little is known about the role of metabolism in this complex developmental process. To address this important knowledge gap, we performed a time-resolved analysis of the metabolic changes associated with bacterial biofilm development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. Here, we report a widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. This report serves as a unique hypothesis-generating resource for future studies on bacterial biofilm physiology. Outside the biofilm research area, this work should also prove relevant to any investigators interested in microbial physiology and metabolism.}, } @article {pmid31113370, year = {2019}, author = {Liu, X and Yan, Y and Wu, H and Zhou, C and Wang, X}, title = {Biological and transcriptomic studies reveal hfq is required for swimming, biofilm formation and stress response in Xanthomonas axonpodis pv. citri.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {103}, pmid = {31113370}, issn = {1471-2180}, mesh = {Bacterial Proteins/genetics ; Biofilms/growth & development ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; Host Factor 1 Protein/*genetics ; *Mutation ; Plant Diseases/microbiology ; Quorum Sensing ; Sequence Analysis, RNA ; Xanthomonas axonopodis/growth & development/*physiology ; }, abstract = {BACKGROUND: Hfq is a widely conserved bacterial RNA-binding protein which generally mediates the global regulatory activities involv ed in physiological process and virulence. The goal of this study was to characterize the biological function of hfq gene in Xanthomonas axonpodis pv. citri (Xac), the causal agent of citrus canker disease.

RESULTS: An hfq mutant in Xac was generated by plasmid integration. The loss of hfq resulted in attenuation of bacterial growth, motility and biofilm formation. In addition, the hfq mutation impaired Xac resistance to H2O2 and both high and low pH environments, but did not affect the virulence to citrus. RNA-Seq analyses indicated that Hfq played roles in regulating the expression of 746 genes. In hfq mutant, gene expression related to chemotaxis, secretion system, two-component system, quorum sensing and flagellar assembly were repressed, whereas expression of ribosomal genes were significantly up-regulated. The down-regulated expression of three bacterial chemotaxis related genes and seven flagella genes, which involved in cell growth and biofilm formation, were further validated by RT-qPCR.

CONCLUSIONS: The study demonstrated that hfq was involved in multiple biological processes in Xac. The results could serve as initiate points for identifying regulatory sRNAs and genes controlled by Hfq-sRNA interactions in Xac.}, } @article {pmid31112769, year = {2019}, author = {Jannadi, H and Correa, W and Zhang, Z and Brandenburg, K and Oueslati, R and Rouabhia, M}, title = {Antimicrobial peptides Pep19-2.5 and Pep19-4LF inhibit Streptococcus mutans growth and biofilm formation.}, journal = {Microbial pathogenesis}, volume = {133}, number = {}, pages = {103546}, doi = {10.1016/j.micpath.2019.103546}, pmid = {31112769}, issn = {1096-1208}, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Drug Combinations ; Drug Synergism ; Humans ; L-Lactate Dehydrogenase/metabolism ; Microbial Sensitivity Tests ; Monocytes/drug effects ; Nerve Tissue Proteins/chemical synthesis/*pharmacology ; Penicillins/pharmacology ; Peptides/chemical synthesis/*pharmacology ; Streptococcus mutans/*drug effects/growth & development ; }, abstract = {With this study, we investigated the effect of synthetic antimicrobial peptides Pep19-2.5 and Pep194LF alone or in combination with antibiotics on S. mutans growth and biofilm formation/disruption. We also examined the cytotoxic effect of each peptide on monocytes. S. mutans was cultured in the presence of different concentrations of each peptide. We showed that Pep19-2.5 and Pep19-4LF were able to significantly (p ≤ 0.01) inhibit the growth of S. mutans. The synthetic peptides also decreased biofilm formation by S. mutans. Furthermore, both peptides reduced the viability of S. mutans in already formed biofilms. The combination of each peptide with antibiotics (penicillin/streptomycin, P/S) produced additive interactions which inhibited S. mutans growth and biofilm formation. Pep19-2.5 and Pep19-4LF were nontoxic, as they did not decrease monocyte viability and did not increase the lactate dehydrogenase activity of the exposed cells. In conclusion, synthetic peptides Pep19-2.5 and Pep19-4LF did inhibit S. mutans growth and its capacity to form biofilm. Both peptides were found to be nontoxic to monocytes. These data provide new insight into the efficacy of synthetic peptides Pep19-2.5 and Pep19-4LF against S. mutans. These peptides may thus be useful in controlling the adverse effects of this cariogenic bacterium in human.}, } @article {pmid31110496, year = {2019}, author = {Rizzato, C and Torres, J and Kasamatsu, E and Camorlinga-Ponce, M and Bravo, MM and Canzian, F and Kato, I}, title = {Potential Role of Biofilm Formation in the Development of Digestive Tract Cancer With Special Reference to Helicobacter pylori Infection.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {846}, pmid = {31110496}, issn = {1664-302X}, abstract = {Bacteria are highly social organisms that communicate via signaling molecules and can assume a multicellular lifestyle to build biofilm communities. Until recently, complications from biofilm-associated infection have been primarily ascribed to increased bacterial resistance to antibiotics and host immune evasion, leading to persistent infection. In this theory and hypothesis article we present a relatively new argument that biofilm formation has potential etiological role in the development of digestive tract cancer. First, we summarize recent new findings suggesting the potential link between bacterial biofilm and various types of cancer to build the foundation of our hypothesis. To date, evidence has been particularly convincing for colorectal cancer and its precursor, i.e., polyps, pointing to several key individual bacterial species, such as Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus gallolyticus subsp. Gallolyticus. Then, we further extend this hypothesis to one of the most common bacterial infection in humans, Helicobacter pylori (Hp), which is considered a major cause of gastric cancer. Thus far, there has been no direct evidence linking in vivo Hp gastric biofilm formation to gastric carcinogenesis. Yet, we synthesize the information to support an argument that biofilm associated-Hp is potentially more carcinogenic, summarizing biological characteristics of biofilm-associated bacteria. We also discuss mechanistic pathways as to how Hp or other biofilm-associated bacteria control biofilm formation and highlight recent findings on Hp genes that influence biofilm formation, which may lead to strain variability in biofilm formation. This knowledge may open a possibility of developing targeted intervention. We conclude, however, that this field is still in its infancy. To test the hypothesis rigorously and to link it ultimately to gastric pathologies (e.g., premalignant lesions and cancer), studies are needed to learn more about Hp biofilms, such as compositions and biological properties of extracellular polymeric substance (EPS), presence of non-Hp microbiome and geographical distribution of biofilms in relation to gastric gland types and structures. Identification of specific Hp strains with enhanced biofilm formation would be helpful not only for screening patients at high risk for sequelae from Hp infection, but also for development of new antibiotics to avoid resistance, regardless of its association with gastric cancer.}, } @article {pmid31109992, year = {2019}, author = {Berne, C and Brun, YV}, title = {The Two Chemotaxis Clusters in Caulobacter crescentus Play Different Roles in Chemotaxis and Biofilm Regulation.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31109992}, issn = {1098-5530}, support = {R35 GM122556/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Caulobacter crescentus/*metabolism ; Chemotaxis/genetics/*physiology ; Cluster Analysis ; Gene Expression Regulation, Bacterial/*physiology ; Mutation ; }, abstract = {The holdfast polysaccharide adhesin is crucial for irreversible cell adhesion and biofilm formation in Caulobacter crescentus Holdfast production is tightly controlled via developmental regulators, as well as via environmental and physical signals. Here, we identify a novel mode of regulation of holdfast synthesis that involves chemotaxis proteins. We characterized the two identified chemotaxis clusters of C. crescentus and showed that only the previously characterized major cluster is involved in the chemotactic response toward different carbon sources. However, both chemotaxis clusters encoded in the C. crescentus genome play a role in biofilm formation and holdfast production by regulating the expression of hfiA, the gene encoding the holdfast inhibitor HfiA. We show that CheA and CheB proteins act in an antagonistic manner, as follows: while the two CheA proteins negatively regulate hfiA expression, the CheB proteins are positive regulators, thus providing a modulation of holdfast synthesis and surface attachment.IMPORTANCE Chemosensory systems constitute major signal transduction pathways in bacteria. These systems are involved in chemotaxis and other cell responses to environment conditions, such as the production of adhesins to enable irreversible adhesion to a surface and surface colonization. The C. crescentus genome encodes two complete chemotaxis clusters. Here, we characterized the second novel chemotaxis-like cluster. While only the major chemotaxis cluster is involved in chemotaxis, both chemotaxis systems modulate C. crescentus adhesion by controlling expression of the holdfast synthesis inhibitor HfiA. Here, we identify a new level in holdfast regulation, providing new insights into the control of adhesin production that leads to the formation of biofilms in response to the environment.}, } @article {pmid31107334, year = {2019}, author = {Stoodley, P}, title = {CORR Insights®: Is Implant Coating With Tyrosol- and Antibiotic-loaded Hydrogel Effective in Reducing Cutibacterium (Propionibacterium) acnes Biofilm Formation? A Preliminary In Vitro Study.}, journal = {Clinical orthopaedics and related research}, volume = {477}, number = {7}, pages = {1747-1749}, pmid = {31107334}, issn = {1528-1132}, mesh = {*Anti-Bacterial Agents ; Biofilms ; Hydrogels ; Phenylethyl Alcohol/analogs & derivatives ; *Propionibacterium acnes ; }, } @article {pmid31107198, year = {2019}, author = {Volejníková, A and Melicherčík, P and Nešuta, O and Vaňková, E and Bednárová, L and Rybáček, J and Čeřovský, V}, title = {Antimicrobial peptides prevent bacterial biofilm formation on the surface of polymethylmethacrylate bone cement.}, journal = {Journal of medical microbiology}, volume = {68}, number = {6}, pages = {961-972}, doi = {10.1099/jmm.0.001000}, pmid = {31107198}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Bone Cements ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development ; Microbial Sensitivity Tests ; Peptides/chemical synthesis/*pharmacology ; Polymethyl Methacrylate ; Prostheses and Implants/microbiology ; Pseudomonas aeruginosa/*drug effects/growth & development ; Staphylococcus epidermidis/*drug effects/growth & development ; }, abstract = {PURPOSE: Antibiotic-loaded polymethylmethacrylate-based bone cement has been implemented in orthopaedics to cope with implant-related infections associated with the formation of bacterial biofilms. In the context of emerging bacterial resistance to current antibiotics, we examined the efficacy of short antimicrobial peptide-loaded bone cement in inhibiting bacterial adhesion and consequent biofilm formation on its surface.

METHODOLOGY: The ability of α-helical antimicrobial peptides composed of 12 amino acid residues to prevent bacterial biofilm [methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli] formation on the surface of model implants made from polymethylmethacrylate-based bone cement was evaluated by colony-forming unit (c.f.u.) counting of bacteria released by sonication from the biofilms formed on their surfaces. The biofilms on model implant surfaces were also visualized by light microscopy after staining with tetrazolium dye (MTT) and by scanning electron microscopy.

RESULTS: When incorporated in the implants, these peptides caused a mean reduction in the number of bacterial cells attached to implants' surfaces (by five orders of magnitude), and 88 % of these implants showed no bacterial adhesion after being exposed to growth media containing various bacteria.

CONCLUSION: The results showed that the antibiofilm activity of these peptides was comparable to that of the antibiotics, but the peptides exhibited broader specificity than the antibiotics. Given the rapid development of antibiotic resistance, antimicrobial peptides show promise as a substitute for antibiotics for loading into bone cements.}, } @article {pmid31106716, year = {2019}, author = {Perez, LRR}, title = {Equal, but different: Fluctuant biofilm formation and its impact on polymyxin B susceptibility among a clonal spreading of KPC-2-producing Klebsiella pneumoniae isolates.}, journal = {Infection control and hospital epidemiology}, volume = {40}, number = {8}, pages = {954-955}, doi = {10.1017/ice.2019.106}, pmid = {31106716}, issn = {1559-6834}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cross Infection/prevention & control ; Humans ; Klebsiella Infections/prevention & control ; Klebsiella pneumoniae/*drug effects/*growth & development ; Microbial Sensitivity Tests ; Polymyxin B/*pharmacology ; }, } @article {pmid31106237, year = {2019}, author = {Colomer-Winter, C and Lemos, JA and Flores-Mireles, AL}, title = {Biofilm Assays on Fibrinogen-coated Silicone Catheters and 96-well Polystyrene Plates.}, journal = {Bio-protocol}, volume = {9}, number = {6}, pages = {}, pmid = {31106237}, issn = {2331-8325}, support = {16PRE29860000/AHA/American Heart Association-American Stroke Association/United States ; R21 AI135158/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilm formation is a well-known bacterial strategy that protects cells from hostile environments. During infection, bacteria found in a biofilm community are less sensitive to antibiotics and to the immune response, often allowing them to colonize and persist in the host niche. Not surprisingly, biofilm formation on medical devices, such as urinary catheters, is a major problem in hospital settings. To be able to eliminate such biofilms, it is important to understand the key bacterial factors that contribute to their formation. A common practice in the lab setting is to study biofilms grown in laboratory media. However, these media do not fully reflect the host environment conditions, potentially masking relevant biological determinants. This is the case during urinary catheterization, where a key element for Enterococcus faecalis and Staphylococcus aureus colonization and biofilm formation is the release of fibrinogen (Fg) into the bladder and its deposition on the urinary catheter. To recapitulate bladder conditions during catheter-associated urinary tract infection (CAUTI), we have developed a fibrinogen-coated catheter and 96-well plate biofilm assay in urine. Notably, enterococcal biofilm factors identified in these in vitro assays proved to be important for biofilm formation in vivo in a mouse model of CAUTI. Thus, the method described herein can be used to uncover biofilm-promoting factors that are uniquely relevant in the host environment, and that can be exploited to develop new antibacterial therapies.}, } @article {pmid31106062, year = {2019}, author = {Khider, M and Hansen, H and Hjerde, E and Johansen, JA and Willassen, NP}, title = {Exploring the transcriptome of luxI[-] and ΔainS mutants and the impact of N-3-oxo-hexanoyl-L- and N-3-hydroxy-decanoyl-L-homoserine lactones on biofilm formation in Aliivibrio salmonicida.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6845}, pmid = {31106062}, issn = {2167-8359}, abstract = {BACKGROUND: Bacterial communication through quorum sensing (QS) systems has been reported to be important in coordinating several traits such as biofilm formation. In Aliivibrio salmonicida two QS systems the LuxI/R and AinS/R, have been shown to be responsible for the production of eight acyl-homoserine lactones (AHLs) in a cell density dependent manner. We have previously demonstrated that inactivation of LitR, the master regulator of the QS system resulted in biofilm formation, similar to the biofilm formed by the AHL deficient mutant ΔainSluxI[-] . In this study, we aimed to investigate the global gene expression patterns of luxI and ainS autoinducer synthases mutants using transcriptomic profiling. In addition, we examined the influence of the different AHLs on biofilm formation.

RESULTS: The transcriptome profiling of ΔainS and luxI[-] mutants allowed us to identify genes and gene clusters regulated by QS in A. salmonicida. Relative to the wild type, the ΔainS and luxI[-] mutants revealed 29 and 500 differentially expressed genes (DEGs), respectively. The functional analysis demonstrated that the most pronounced DEGs were involved in bacterial motility and chemotaxis, exopolysaccharide production, and surface structures related to adhesion. Inactivation of luxI, but not ainS genes resulted in wrinkled colony morphology. While inactivation of both genes (ΔainSluxI[-]) resulted in strains able to form wrinkled colonies and mushroom structured biofilm. Moreover, when the ΔainSluxI[-] mutant was supplemented with N-3-oxo-hexanoyl-L-homoserine lactone (3OC6-HSL) or N-3-hydroxy-decanoyl-L-homoserine lactone (3OHC10-HSL), the biofilm did not develop. We also show that LuxI is needed for motility and for repression of EPS production, where repression of EPS is likely operated through the RpoQ-sigma factor.

CONCLUSION: These findings imply that the LuxI and AinS autoinducer synthases play a critical role in the regulation of biofilm formation, EPS production, and motility.}, } @article {pmid31105285, year = {2019}, author = {Samad, A and Khan, AA and Sajid, M and Zahra, R}, title = {Assessment of biofilm formation by pseudomonas aeruginosa and hydrodynamic evaluation of microtiter plate assay.}, journal = {JPMA. The Journal of the Pakistan Medical Association}, volume = {69}, number = {5}, pages = {666-671}, pmid = {31105285}, issn = {0030-9982}, mesh = {Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Computer Simulation ; Humans ; Hydrodynamics ; Pseudomonas aeruginosa/genetics/*physiology ; }, abstract = {OBJECTIVE: To assess the biofilm formation in clinical and environmental isolates of Pseudomonas aeruginosa and to evaluate the hydrodynamics in microtiter plate assay and compare it with conventional assays for biofilm formation.

METHODS: The cross-sectional study was conducted at the Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan, in 2013-14, while the computational work was done at the National University of Science and Technology, Islamabad. The study comprised environmental and clinical isolates of pseudomonas aeruginosa. Pseudomonas citramide agar was used as a selective media, and further confirmation was done by biochemical tests. Biofilm formation was assessed by Congo red assay, air liquid interfaceassay and microtiter plate assay. Computational Fluid Dynamics (CFD) simulations were also used to improve the microtiter plate assay for biofilm formation assessment. Polymerase chain reaction was used for screening of pelA and pelG genes.

RESULTS: Of the 50 isolates, 25(50%) each were environmental and clinical. The number of biofilm producers observed in Congo red assay, air liquid interface assay and microtiter plate assay were 7(14%), 15(30%) and 30(60%) respectively. Biofilm former gene pelA was observed in 22(44%) isolates while 36(72%) isolates showed the presence of pelG gene.

CONCLUSIONS: Microtiter plate assay was found to be a reliable method to detect biofilm forming pseudomonas aeruginosa isolates which further provides a base for development of methods to detect biofilms readily and accurately.}, } @article {pmid31104214, year = {2019}, author = {Aiyer, KS and Vijayakumar, BS}, title = {An improvised microtiter dish biofilm assay for non-invasive biofilm detection on microbial fuel cell anodes and studying biofilm growth conditions.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {50}, number = {3}, pages = {769-775}, pmid = {31104214}, issn = {1678-4405}, mesh = {Bacteria/*growth & development ; Bacterial Physiological Phenomena ; Bacteriological Techniques/*methods ; Bioelectric Energy Sources/*microbiology ; *Biofilms ; Electrodes/*microbiology ; }, abstract = {Microbial life is predominantly observed as biofilms, which are a sessile aggregation of microbial cells formed in response to stress conditions. The microtiter dish biofilm formation assay is one of the most important methods of studying biofilm formation. In this study, the assay has been improvised to allow easy detection of biofilm formation on different substrata. The method has then been used to study growth conditions that affect biofilm formation, viz., the effect of pH, temperature, shaking conditions, and the carbon source provided. Glass, cellulose acetate, and carbon cloth materials were used as substrata to study biofilm development under the above conditions. The method was then extended to determine biofilm formation on the anodes of a microbial fuel cell in order to study the effect of biofilm formation on power production. A high correlation was observed between biofilm formation and power density (r = 0.951). When the electrode containing a biofilm was replaced with another electrode without biofilm, the average power density dropped from 59.55 to 5.76 mW/m[2]. This method offers an easy way to study the suitability of different materials to support biofilm formation. Growth conditions determining biofilm formation can be studied using this method. This method also offers a non-invasive way to determine biofilm formation on anodes of microbial fuel cells and preserves the anode for further studies.}, } @article {pmid31102859, year = {2019}, author = {Liang, C and Zhang, L and Nord, NB and Carvalho, PN and Bester, K}, title = {Dose-dependent effects of acetate on the biodegradation of pharmaceuticals in moving bed biofilm reactors.}, journal = {Water research}, volume = {159}, number = {}, pages = {302-312}, doi = {10.1016/j.watres.2019.04.026}, pmid = {31102859}, issn = {1879-2448}, mesh = {Biodegradation, Environmental ; *Biofilms ; Bioreactors ; Waste Disposal, Fluid ; Wastewater ; *Water Pollutants, Chemical ; }, abstract = {Moving bed biofilm reactors (MBBR) are promising as a post-treatment for removing pharmaceuticals from wastewater. However, the effect of easily degradable carbon sources on the degradation of pharmaceuticals is unclear. This study shows the influence of acetate on the degradation of 26 pharmaceuticals in an MBBR was dose- and compound-dependent: while the degradation of venlafaxine, tramadol and ciprofloxacin was promoted (increase of reaction rate constant (k) by 133%, 212%, 55%) by acetate, its presence caused negative effects on the removal of ibuprofen, citalopram and diclofenac (decrease of k by 76%, 57%, 44%). The deconjugation of acetyl-sulfadiazine was clearly slowed down (decrease of k by 75%) by the dosed acetate, probably due to feedback inhibition by abundant acetate. 17 out of 25 tested compounds were found to be independent of the acetate dosage, which suggested dosing acetate induced minor effects on most of pharmaceuticals' removal. Enrichment of S- or first eluted enantiomer of 4 β-blockers and the metabolite metoprolol acid was observed. Both non-enantioselective (rapid at elevated compound concentration) and enantioselective enzymes (slower and predominant at lower compound concentration) played a part in the biodegradation. High doses of acetate slowed down the enantiomeric enrichment of atenolol, metoprolol, propranolol and metoprolol acid, which demonstrated that the acetate is able to up- or down-regulate enzymes involved in the enantioselective degradation of β-blockers and thus reveals a complex co-metabolism relationship between transformation pathways of pharmaceuticals and carbon source.}, } @article {pmid31102615, year = {2019}, author = {Campbell, M and Zhao, W and Fathi, R and Mihreteab, M and Gilbert, ES}, title = {Rhamnus prinoides (gesho): A source of diverse anti-biofilm activity.}, journal = {Journal of ethnopharmacology}, volume = {241}, number = {}, pages = {111955}, doi = {10.1016/j.jep.2019.111955}, pmid = {31102615}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects/physiology ; Gram-Positive Bacteria/drug effects/physiology ; Plant Extracts/*pharmacology ; Plant Leaves ; Plant Stems ; *Rhamnus ; }, abstract = {Rhamnus prinoides (gesho) is an evergreen shrub from East Africa traditionally used for the treatment of illnesses including atopic dermatitis, ear, nose and throat infections, pneumonia, arthritis, brucellosis, flu, indigestion and fatigue.

AIM OF THE STUDY: Several of the conditions for which gesho is traditionally used are associated with communities of surface-attached microorganisms, or biofilms. We hypothesized that gesho has anti-biofilm activity. The principal aim of this study was to evaluate gesho-associated anti-biofilm activity and identify active compounds.

MATERIALS AND METHODS: Lyophilized ethanol and aqueous extracts were prepared from dried Rhamnus prinoides stems and leaves. Biofilm inhibition was measured by crystal violet staining and subsequent viability assays were conducted on growth agar. Chemical fractionation, chemical testing, Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) were used to isolate and identify active compounds.

RESULTS: Leaf and stem ethanol extracts significantly inhibited Staphylococcus aureus, Bacillus subtilis and Streptococcus mutans biofilm formation up to 99.9% and reduced planktonic cell growth up to 10 log units relative to untreated controls. The anti-biofilm activity of the ethanol stem extracts was due to a biocidal or bacteriostatic mechanism while bacteriostatic or anti-pathogenic mechanisms were attributed to the leaf ethanol extract. Gesho extracts showed activity against all three species tested but the treatment efficacy and mechanism were species dependent. Chemical fractionation and activity screens of the leaf ethanol extract identified ethyl 4-ethoxybenzoate and 4-hydroxy 4-methyl pentanone to be compounds with anti-biofilm activity. Ethyl 4-ethoxybenzoate activity was potentiated by DMSO. Notably, concentrations of both compounds were identified where biofilm formation was prevented without inhibition of cell growth; i.e. anti-pathogenic characteristics were evident.

CONCLUSION: Gesho leaf ethanol extract contains chemicals with anti-biofilm and bactericidal activities. This work lends support to the traditional use of gesho for treating topical infections and warrants further investigation into Rhamnus prinoides as a source of antibacterial and anti-biofilm agents.}, } @article {pmid31102398, year = {2019}, author = {Carvajal, J and Carvajal, M}, title = {Further Clarification About "Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?".}, journal = {Aesthetic surgery journal}, volume = {39}, number = {7}, pages = {NP295-NP297}, doi = {10.1093/asj/sjz076}, pmid = {31102398}, issn = {1527-330X}, mesh = {*Anti-Infective Agents, Local ; Biofilms ; *Breast Implantation ; *Contracture ; Humans ; Implant Capsular Contracture ; }, } @article {pmid31100490, year = {2019}, author = {Senpuku, H and Mohri, S and Mihara, M and Arai, T and Suzuki, Y and Saeki, Y}, title = {Effects of 7S globulin 3 derived from the adzuki bean [Vigna angularis] on the CSP- and eDNA- dependent biofilm formation of Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {102}, number = {}, pages = {256-265}, doi = {10.1016/j.archoralbio.2019.04.010}, pmid = {31100490}, issn = {1879-1506}, mesh = {Bacterial Proteins ; Biofilms ; *Dental Caries ; Globulins ; Peptides ; Streptococcus mutans ; *Vigna ; }, abstract = {OBJECTIVE: Streptococcus mutans is a principal bacterium that forms pathogenic biofilm involved in the development of dental caries. S. mutans possesses a quorum sensing system (QS) stimulated by competence stimulating peptide (CSP), which is associated with bacteriocin production, genetic competency and biofilm formation. Inhibiting CSP-dependent QS is one of the aims leading to the inhibition of biofilm formation and is useful for establishing new prevention systems for dental caries.

DESIGN: In this study, we selected adzuki bean [Vigna angularis] extract as a candidate component to inhibit CSP-dependent biofilm formation among various foods. To purify an inhibitory component from the adzuki extracts, we performed the salting-out method, two rounds of ion-exchange chromatography, and SDS and native PAGE.

RESULTS: A primary protein band that inhibits CSP-dependent biofilm formation appeared at approximately 50 kDa and was identified as 7S globulin 3 (7S3), a major seed storage protein in adzuki bean. To determine the characteristics of 7S3 as an inhibitory component, aggregated proteins were extracted from the adzuki crude extracts at pH values lower than 6. The aggregated proteins inhibited CSP- and eDNA-dependent biofilm formation and showed 50 kDa band, which is identical with 7S3 in the purified sample. Moreover, 7S globulin 3 in the adzuki bean extract directly interacted with CSP at low pH conditions but not at neutral conditions, and inhibited CSP-dependent bacteriocin production.

CONCLUSION: It was suggested that 7S3 might be a safe and useful material to prevent pathogenic activities in the biofilm formation of S. mutans.}, } @article {pmid31100153, year = {2020}, author = {Lin, CJ and Hou, YH and Chen, YL}, title = {The histone acetyltransferase GcnE regulates conidiation and biofilm formation in Aspergillus fumigatus.}, journal = {Medical mycology}, volume = {58}, number = {2}, pages = {248-259}, doi = {10.1093/mmy/myz043}, pmid = {31100153}, issn = {1460-2709}, mesh = {Animals ; Aspergillus fumigatus/enzymology/*genetics/growth & development ; Biofilms/*growth & development ; Female ; Fungal Proteins/*genetics/metabolism ; Gene Deletion ; *Gene Expression Regulation, Fungal ; Histone Acetyltransferases/*genetics/metabolism ; Invasive Fungal Infections/microbiology ; Mice ; Mice, Inbred ICR ; Mutation ; Nitrogen/metabolism ; Spores, Fungal/*genetics/growth & development ; Virulence ; }, abstract = {Histone modifications play a crucial role in eukaryotic gene regulation. The Spt-Ada-Gcn5-acetyltransferase (SAGA) complex controls histone acetylation, with Gcn5 (GcnE) acting as the acetyltransferase. In the Aspergillus species, GcnE has been shown to regulate asexual development and secondary metabolism. Apart from this, GcnE is required for pathogenicity in plant fungal pathogen A. flavus; however, the role of GcnE in the pathogenicity of human pathogenic fungus A. fumigatus is unknown. In this study, we uncovered the key roles of GcnE in A. fumigatus conidiation, stress responses, and biofilm formation. We observed that deletion of gcnE resulted in aberrant conidiation in which conidiophores displayed abnormal phialide formation. In addition, the ΔgcnE mutant grew slightly faster under limited nitrogen sources (1 mM of ammonium or nitrate) compared to the wild type. The ΔgcnE mutant exhibited increased susceptibility to cell wall-perturbing agents, H2O2 and menadione but enhanced tolerance to LiCl. Furthermore, we showed that GcnE is involved in biofilm formation, and overexpression of adherence-related genes such as somA or uge3 partially rescued biofilm formation defects in the ΔgcnE mutant background. Interestingly, GcnE was not required for virulence in a neutropenic murine model of invasive aspergillosis. These results suggest that GcnE is critical for conidiation and biofilm formation but not virulence in A. fumigatus.}, } @article {pmid31099708, year = {2019}, author = {Sato, A and Yamaguchi, T and Hamada, M and Ono, D and Sonoda, S and Oshiro, T and Nagashima, M and Kato, K and Okazumi, S and Katoh, R and Ishii, Y and Tateda, K}, title = {Morphological and Biological Characteristics of Staphylococcus aureus Biofilm Formed in the Presence of Plasma.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {5}, pages = {668-676}, pmid = {31099708}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Culture Media, Serum-Free/chemistry/pharmacology ; Daptomycin/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/growth & development/isolation & purification ; Microbial Sensitivity Tests ; Rheology ; Staphylococcal Infections/drug therapy/microbiology ; Vancomycin/*pharmacology ; }, abstract = {Characteristics of Staphylococcus aureus infections include biofilm formation, leading to the spread of bacteria to the bloodstream causing sepsis and metastatic infections. In particular, in methicillin-resistant S. aureus (MRSA) infections, biofilm formation critically hampers treatment and causes poor prognosis. We explored the biofilm formation of MRSA in the presence or absence of plasma and compared morphological characteristics, accumulation of antibiotics, and resistance to bactericidal activity, using continuous optimizing confocal reflection microscopy. Addition of plasma significantly increased biofilm formation, which is characterized by an uneven surface and aggregation of bacteria (hereafter plasma biofilm). The flow-cell system, which enabled a continuous supply of plasma, accelerated biofilm formation in both the tested strains of MRSA (BAA1556 and N315). Accumulation of green fluorescence-labeled vancomycin was observed within 5 minutes in the plasma-free biofilm, but not in the plasma biofilm. Delay of accumulation was also observed for daptomycin in plasma biofilm. Plasma biofilm bacteria were more resistant to anti-MRSA antibiotics than plasma-free biofilm bacteria. These data demonstrate that the plasma biofilm of S. aureus is substantially different from the plasma-free biofilm. Plasma biofilm, especially in the flow-cell system, could be a clinically relevant model to analyze MRSA infections and treatment.}, } @article {pmid31099211, year = {2018}, author = {André, CB and Chan, DC and Giannini, M}, title = {Antibacterial-containing dental adhesives' effects on oral pathogens and on Streptococcus mutans biofilm: Current perspectives.}, journal = {American journal of dentistry}, volume = {31}, number = {Sp Is B}, pages = {37B-41B}, pmid = {31099211}, issn = {0894-8275}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Dental Cements ; Dentin ; Dentin-Bonding Agents ; Humans ; Resin Cements ; *Streptococcus mutans/drug effects ; }, abstract = {PURPOSE: To describe the literature findings regarding commercially available antibacterial-containing dental adhesives and the futures perspectives of this field.

RESULTS: High-risk caries patients could yield benefits from restorative materials containing antibacterial properties in order to reduce the recurrent caries formation. Dental adhesives with antibacterial agents may reduce restoration replacement, as recurrent caries is still one of the major reasons for replacing a resin restoration. Literature results of three commercially available adhesives: Gluma 2Bond, Clearfil SE Protect and Peak Universal Bond, containing glutaraldehyde, MDPB and chlorhexidine, respectively indicates that Clearfil SE Protect seems to have better results against oral pathogens and on Streptococcus mutans biofilm. Besides the promising findings, clinical studies are still necessary in order to validate the clinical efficacy when exposed to a more complex environment and the long-term effect of either commercially available materials, experimental antibacterial monomers or antibacterial incorporations. As a suggestion of this article and according to the current scientific trends in this specific field, future directions should focus on restorative materials with therapeutic components targeting the virulence factors of cariogenic biofilm with minimal toxicity and side effects, and long-term action.

CLINICAL SIGNIFICANCE: Antibacterial-containing dental adhesives may have therapeutic effects, working as an additional source to reduce recurrent caries development in patients with high-risk of caries, and consequently the reduction in restoration replacements.}, } @article {pmid31099066, year = {2019}, author = {Ali, SE and Songe, MM and Skaar, I}, title = {Colorimetric assay for the in vitro evaluation of Saprolegnia biofilm inhibitors.}, journal = {Journal of fish diseases}, volume = {42}, number = {8}, pages = {1119-1124}, doi = {10.1111/jfd.13017}, pmid = {31099066}, issn = {1365-2761}, support = {238550//European Commission through the EU Marie Curie ITN project and CGIAR Research Program on Fish Agri-Food Systems (FISH). SAPRO/ ; }, mesh = {Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Boric Acids/*pharmacology ; Colorimetry/*veterinary ; Infection Control ; Propionates/*pharmacology ; Propylene Glycols/*pharmacology ; Saprolegnia/*drug effects/*physiology ; }, abstract = {A quantitative and reproducible 96-well microtiter method that is easily adaptable for the screening of Saprolegnia biofilm inhibitors is described. As opposed to other methods previously developed for the screening of Saprolegnia inhibitors on spore germination or mycelial growth, this technique is of particular significance as it investigates potential inhibitors against surface-attached mycelial mats of Saprolegnia spp. (biofilm). In this study, we have investigated the effects of propionic acid (PPA) on reducing the viability of induced Saprolegnia biofilms using colorimetric MTS assay based on the reduction of tetrazolium salts. Viability of Saprolegnia hyphae in treated biofilms was reduced significantly following treatment with different PPA concentrations. The effect was enhanced after combining each of the tested PPA concentrations with 500 mg/L of boric acid (BA). However, the percentage of non-viable hyphae was still higher in 200 mg L[-1] bronopol-treated biofilms (positive control) following 6- and 12-hr exposure. Similar results were observed using other recently described fluorescence-based assays for viability.}, } @article {pmid31098293, year = {2019}, author = {Dubois, T and Tremblay, YDN and Hamiot, A and Martin-Verstraete, I and Deschamps, J and Monot, M and Briandet, R and Dupuy, B}, title = {A microbiota-generated bile salt induces biofilm formation in Clostridium difficile.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {14}, pmid = {31098293}, issn = {2055-5008}, mesh = {Bacterial Proteins/analysis ; Biofilms/*drug effects/*growth & development ; Clostridioides difficile/*drug effects/*growth & development ; DNA, Bacterial/analysis ; Deoxycholic Acid/*metabolism ; Extracellular Polymeric Substance Matrix/chemistry ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Gene Regulatory Networks ; Metabolic Networks and Pathways/drug effects ; }, abstract = {Clostridium difficile is a major cause of nosocomial infections. Bacterial persistence in the gut is responsible for infection relapse; sporulation and other unidentified mechanisms contribute to this process. Intestinal bile salts cholate and deoxycholate stimulate spore germination, while deoxycholate kills vegetative cells. Here, we report that sub-lethal concentrations of deoxycholate stimulate biofilm formation, which protects C. difficile from antimicrobial compounds. The biofilm matrix is composed of extracellular DNA and proteinaceous factors that promote biofilm stability. Transcriptomic analysis indicates that deoxycholate induces metabolic pathways and cell envelope reorganization, and represses toxin and spore production. In support of the transcriptomic analysis, we show that global metabolic regulators and an uncharacterized lipoprotein contribute to deoxycholate-induced biofilm formation. Finally, Clostridium scindens enhances biofilm formation of C. difficile by converting cholate into deoxycholate. Together, our results suggest that deoxycholate is an intestinal signal that induces C. difficile persistence and may increase the risk of relapse.}, } @article {pmid31097723, year = {2019}, author = {Passos da Silva, D and Matwichuk, ML and Townsend, DO and Reichhardt, C and Lamba, D and Wozniak, DJ and Parsek, MR}, title = {The Pseudomonas aeruginosa lectin LecB binds to the exopolysaccharide Psl and stabilizes the biofilm matrix.}, journal = {Nature communications}, volume = {10}, number = {1}, pages = {2183}, pmid = {31097723}, issn = {2041-1723}, support = {R01 AI134895/AI/NIAID NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; 5R01AI077628//U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/International ; W911NF1810254//United States Department of Defense | United States Army | Army Medical Command | U.S. Army Research Institute of Environmental Medicine (United States Army Research Institute of Environmental Medicine)/International ; }, mesh = {*Biofilms ; Intravital Microscopy ; Lectins/isolation & purification/*metabolism ; Microscopy, Confocal ; Molecular Docking Simulation ; Polysaccharides, Bacterial/*metabolism ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Pseudomonas aeruginosa biofilms are composed of exopolysaccharides (EPS), exogenous DNA, and proteins that hold these communities together. P. aeruginosa produces lectins LecA and LecB, which possess affinities towards sugars found in matrix EPS and mediate adherence of P. aeruginosa to target host cells. Here, we demonstrate that LecB binds to Psl, a key matrix EPS, and this leads to increased retention of both cells and EPS in a growing biofilm. This interaction is predicted to occur between the lectin and the branched side chains present on Psl. Finally, we show that LecB coordinates Psl localization in the biofilm. This constitutes a unique function for LecB and identifies it as a matrix protein that contributes to biofilm structure through EPS interactions.}, } @article {pmid31096414, year = {2019}, author = {Oprei, A and Zlatanović, S and Mutz, M}, title = {Grazers superimpose humidity effect on stream biofilm resistance and resilience to dry-rewet stress.}, journal = {The Science of the total environment}, volume = {659}, number = {}, pages = {841-850}, doi = {10.1016/j.scitotenv.2018.12.316}, pmid = {31096414}, issn = {1879-1026}, mesh = {Animals ; *Biofilms ; *Climate Change ; *Droughts ; Feeding Behavior ; Germany ; Humidity ; Microbiota/*physiology ; Rivers/*microbiology ; Snails/*physiology ; Time Factors ; }, abstract = {Temperate low order streams increasingly experience intermittency and drying due to climate change. In comparison to well-studied Mediterranean streams, drying events in canopied temperate streams occur under higher ambient humidity which probably affects the metabolic response to drying. Previous work on drying sediments (in temperate streams) did not consider the interactions of trophic levels. We hypothesized that preservation of sediment moisture due to high humidity increases resistance to drying in temperate streambed biofilms and fast resilience of biofilm activity after flow resumption. We also expected the presence of macroinvertebrate grazers to modulate the biofilm response to dry-rewet stress. Following a two-level factorial design in 24 microcosms, we tested the effect of drying intensity (moderate and intense) and grazer presence and absence (P. antipodarum) on the activity of biofilm colonizing shallow hyporheic sediment. We measured the community respiration over a drying period of 27 days, a single rewetting event and a follow-up of three days. Grazer presence stimulated biofilm community respiration (CRmic) in the permanently wet control, but decreased biofilm resistance to desiccation (<0.2% of pre-disturbed activity), regardless of drying intensity. In the absence of grazers, higher atmospheric humidity in moderately drying microcosms resulted in maintaining a film of adhesive water and low CRmic (29% of pre-disturbed respiration) until the end of the drying period. After flow resumption, the CRmic increased within 8 h, achieving 79-83% of pre-disturbed respiration (no grazers) and 15-41% (with grazers), respectively. Results show that short dry periods in temperate streams, even under high humidity, impact the streambed biofilm community negatively. The complex response and strong effect of grazer presence indicates that experiments including interactions of trophic levels and settings mimicking environmental factors during dry-rewet stress are needed.}, } @article {pmid31096410, year = {2019}, author = {Ramírez-Vargas, CA and Arias, CA and Carvalho, P and Zhang, L and Esteve-Núñez, A and Brix, H}, title = {Electroactive biofilm-based constructed wetland (EABB-CW): A mesocosm-scale test of an innovative setup for wastewater treatment.}, journal = {The Science of the total environment}, volume = {659}, number = {}, pages = {796-806}, doi = {10.1016/j.scitotenv.2018.12.432}, pmid = {31096410}, issn = {1879-1026}, mesh = {Biodegradation, Environmental ; *Biofilms ; Coke/*analysis ; Electrodes ; Nitrogen/analysis ; Sulfur/analysis ; Waste Disposal, Fluid/*methods ; Wastewater/*analysis ; Water Pollutants, Chemical/*analysis ; *Wetlands ; }, abstract = {Constructed wetlands (CWs) performance enhancement can be done with intensification strategies. A recent strategy still in study is the coupling with Microbial Electrochemical Technologies (MET). An alternative system using electro-conductive biofilters instead of electrodes and circuits used in MET, resulted in the development of a Microbial Electrochemical-based CW (METland). This system relies on electroactive bacteria (EAB) metabolism to transfer electrons to an electro-conductive material, thus boosting substrate consumption, and diminishing electron availability for biomass build-up and methane generation. In previous studies this biofilters have shown an improvement in biodegradation rates in comparison with subsurface flow CW. However, this set-up is still in development, hence there are uncertainties regarding the dynamics involve in the removal of pollutants. Considering that, this work aimed at establishing the capacity and removal kinetics of organic matter and nutrients in an Electroactive Biofilm-Based CW (EABB-CW). Two electro-conductive materials were tested (PK-A and PK-LSN) in planted and non-planted mesocosms and compared with sand. The systems were operated in a continuous upflow mode for 32 weeks and fed with real wastewater. The electro-conductive systems reached removal efficiencies up to 88% for BOD5, 90% for COD, 46% for NH4-N, and 86% for PO4-P. Organic matter removal in electro-conductive systems was possible even at loading rates 10-fold higher than recommended for horizontal flow CWs. First-order area-based removal constants (k), calculated for organic matter and nutrients are higher than values typically reported for saturated CW and in certain cases comparable with vertical flow CW. The organic removal was correlated with electron current densities measures, as indicator of the presence of EAB. The tested EABB-CW profiles as a promising CW type for the removal of organic matter and PO4-P with margin for modifications to improve nitrogen removal. Future studies with pilot/real scale systems are proposed to validate the findings of this study.}, } @article {pmid31095299, year = {2019}, author = {Hogan, S and Kasotakis, E and Maher, S and Cavanagh, B and O'Gara, JP and Pandit, A and Keyes, TE and Devocelle, M and O'Neill, E}, title = {A novel medical device coating prevents Staphylococcus aureus biofilm formation on medical device surfaces.}, journal = {FEMS microbiology letters}, volume = {366}, number = {9}, pages = {}, doi = {10.1093/femsle/fnz107}, pmid = {31095299}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antithrombins/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; *Coated Materials, Biocompatible ; Equipment and Supplies/*microbiology ; Humans ; Microscopy, Electron, Scanning ; Polyurethanes/chemistry/pharmacology ; Staphylococcal Infections/microbiology/prevention & control ; Staphylococcus aureus/*drug effects/ultrastructure ; Surface Properties ; Thrombin/metabolism ; }, abstract = {Prevention of device related infections due to Staphylococcus aureus biofilms on devices represents a significant challenge. Such infections have recently been shown to be dependent on the coagulation pathway via activation of pro-thrombin and fibrin production. Three direct-thrombin inhibitors, argatroban, hirudin and dabigatran, were examined to determine their effect on preventing S. aureus biofilm on plastic biochip surfaces under shear stress using an in vivo relevant model of infection. Surface functionalization of polyurethane discs via dityrosine covalent crosslinking with hirudin was performed and changes in bacterial density and microscopic appearances determined. The three direct-thrombin inhibitors prevented S. aureus biofilm formation on plasma-coated surfaces treated with these agents. Coating of polyurethane with one of these agents, hirudin, significantly inhibited biofilm formation on the modified surface. These findings reveal the exciting potential for coating biomaterial surfaces with direct thrombin inhibitors to prevent staphylococcal binding and subsequent device-related infections.}, } @article {pmid31093442, year = {2019}, author = {Reda, FM}, title = {Antibacterial and anti-adhesive efficiency of Pediococcus acidilactici against foodborne biofilm producer Bacillus cereus attached on different food processing surfaces.}, journal = {Food science and biotechnology}, volume = {28}, number = {3}, pages = {841-850}, pmid = {31093442}, issn = {2092-6456}, abstract = {This study aimed to assess the biofilm formation by Bacillus cereus on two novel surfaces namely: aluminum and cold steel in comparison study with stainless steel and polystyrene. Also, it aimed to study the inhibitory effect of a new strain Pediococcus acidilactici against biofilm formation by B. cereus grown on these surfaces. In this study, B. cereus M50 isolated from milky machine surface was selected as the highest biofilm producer. The number of M50 cells adhered to aluminum and stainless steel surfaces were more than that adhered to polystyrene and cold steel, respectively. The antimicrobial, anti-adhesive and SEM studies revealed that the P. acidilactici P12 culture and its cell free filtrate showed a significant potential inhibition of biofilm formation of M50 on all tested surfaces under different conditions. These results demonstrated that P. acidilactici strain are considered a new biotreatment for biofilm destruction of food borne pathogens, food biopreservation and food safety.}, } @article {pmid31091746, year = {2019}, author = {Yang, CH and Su, PW and Moi, SH and Chuang, LY}, title = {Biofilm Formation in Acinetobacter Baumannii: Genotype-Phenotype Correlation.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {10}, pages = {}, pmid = {31091746}, issn = {1420-3049}, support = {106-2221-E-214-043, 107-2221-E-214-013 and 106-2221-E-151-009-MY2//Ministry of Science and Technology/ ; }, mesh = {Acinetobacter baumannii/drug effects/genetics/*physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Genetic Association Studies ; Microbial Sensitivity Tests ; Taiwan ; }, abstract = {Strains of Acinetobacter baumannii are commensal and opportunistic pathogens that have emerged as problematic hospital pathogens due to its biofilm formation ability and multiple antibiotic resistances. The biofilm-associated pathogens usually exhibit dramatically decreased susceptibility to antibiotics. This study was aimed to investigate the correlation of biofilm-forming ability, antibiotic resistance and biofilm-related genes of 154 A. baumannii isolates which were collected from a teaching hospital in Taiwan. Biofilm-forming ability of the isolates was evaluated by crystal violet staining and observed by scanning electron microscopy. Antibiotic susceptibility was determined by disc diffusion method and minimum inhibitory concentration; the biofilm-related genes were screened by polymerase chain reaction. Results showed that among the 154 tested isolates, 15.6% of the clinical isolates were weak biofilm producers, while 32.5% and 45.4% of them possessed moderate and strong biofilm formation ability, respectively. The experimental results revealed that the multiple drug resistant isolates usually provided a higher biofilm formation. The prevalence of biofilm related genes including bap, blaPER-1, csuE and ompA among the isolated strains was 79.2%, 38.3%, 91.6%, and 68.8%, respectively. The results indicated that the antibiotic resistance, the formation of biofilm and the related genes were significantly correlated. The results of this study can effectively help to understand the antibiotic resistant mechanism and provides the valuable information to the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens.}, } @article {pmid31829990, year = {2018}, author = {Yazgan, B and Türkel, I and Güçkan, R and Kılınç, K and Yıldırım, T}, title = {Comparison of biofilm formation and efflux pumps in ESBL and carbapenemase producing Klebsiella pneumoniae.}, journal = {Journal of infection in developing countries}, volume = {12}, number = {3}, pages = {156-163}, doi = {10.3855/jidc.9677}, pmid = {31829990}, issn = {1972-2680}, abstract = {INTRODUCTION: Klebsiella pneumoniae is an opportunistic pathogen that causes a range of diseases. The appearance of extended-spectrum β-lactamase -and carbapenemase-producing strains, in addition to the biofilm-forming phenotype, is a major problem in the clinical environment.

METHODOLOGY: A total of 33 clinical K. pneumoniae isolates were used in this study. Antimicrobial susceptibilities were assessed by a disc diffusion assay. Biofilm formation was determined by a microtiter plate assay, staining with 1% crystal violet and measuring  absorbance after destaining. Moreover, expression of acrA, kdeA, ketM, kpnEF, and kexD efflux associated genes  was measured by qRT-PCR.

RESULTS: Isolates displayed high resistance to β-lactams such as cefazolin, cefuroxime, ceftriaxone, cefepime, piperacillin-tazobactam, imipenem, and meropenem and decreased resistance to gentamicin, amikacin, ciprofloxacin, and levofloxacin. ESBL-producing isolates formed more biofilm than carbapenemase-producing isolates. The mRNA expression levels in KPC isolates for acrA (2-fold), kdeA (2.7-fold), ketM (2.2-fold), and kpnEF (3.4-fold) were significantly increased compared to ESBL-producing isolates. There was no significant difference in kexD expression level.

CONCLUSIONS: Under the conditions used here ESBL-producing isolates formed more biofilm than KPC postive isolates; this was associated with virulence determinants which were also transferred by plasmids together with ESBLs enzymes. Moreover, the upregulation of acrA, kdeA, ketM, and kpnEF efflux pumps was seen in carbapenemase-producing isolates demonstrating that high expression of efflux pumps alone could not confer resistance but may act as a physiological determinant such as bacterial pathogenicity and virulence, and cell-to-cell communication for bacteria.}, } @article {pmid31294215, year = {2018}, author = {Di Martino, P}, title = {Extracellular polymeric substances, a key element in understanding biofilm phenotype.}, journal = {AIMS microbiology}, volume = {4}, number = {2}, pages = {274-288}, pmid = {31294215}, issn = {2471-1888}, abstract = {One of the key elements in the establishment and maintenance of the biofilm structure and properties is the extracellular matrix. The extracellular matrix is composed of water and extracellular polymeric substances (EPS): primarily polysaccharides, proteins and DNA. Characterization of the matrix requires component identification, as well as determination of the relative concentration of EPS constituents, including their physicochemical properties and descriptions of their interactions. Several types of experimental approaches with varying degrees of destructiveness can be utilized for this characterization. The analysis of biofilm by infrared spectroscopy gives information about the chemical content of the matrix and the proportions of different EPS. The sensitivity of a biofilm to hydrolytic enzymes targeting different EPS gives insight into the composition of the matrix and the involvement of matrix components in the integrity of the structure. Using both chemical and physical treatments, extraction and purification of EPS from the biofilm also provides a means of determining matrix composition. Purified and/or artificial EPS can be used to obtain artificial matrices and to study their properties. Using examples from the literature, this review will illustrate selected technologies useful in the study of EPS that provide a better understanding of the structure-function relationships in extracellular matrix, and thus the structure-function relationships of the biofilm phenotype.}, } @article {pmid31294211, year = {2018}, author = {Wallis, JK and Krömker, V and Paduch, JH}, title = {Biofilm formation and adhesion to bovine udder epithelium of potentially probiotic lactic acid bacteria.}, journal = {AIMS microbiology}, volume = {4}, number = {2}, pages = {209-224}, pmid = {31294211}, issn = {2471-1888}, abstract = {Mastitis is one of the most important diseases threatening modern dairy herds. The idea of fighting the disease through colonising the udder with lactic acid bacteria (LAB), thereby building a beneficial biofilm, is the base for a probiotic approach towards mastitis control. The purpose of this study was to screen 13 LAB strains (eleven wild strains, two ATCC strains) inhibitory to the growth of mastitis-causing pathogens for their in vitro ability to form a biofilm and to adhere to bovine glandular mammary epithelium in order to assess their probiotic potential. Furthermore, we aimed to gain knowledge about the chemical nature of the adhesins involved by subjecting the bacteria to various chemical and enzymatical pre-treatments. The biofilms were grown on hydrophilic glass and on hydrophobic polypropylene in de Man, Rogosa and Sharpe (MRS) broth and afterwards quantified with a crystal violet assay. Biofilm formation was observed in all strains. However, the extent strongly depended on the strain, surface charge and medium. The adhesion assay also revealed a strong strain dependency, but this trait was also present in all of the investigated LAB isolates. Depending on the strain, chemical or enzymatical pre-treatment revealed carbohydrate molecules as well as proteins and lipids to be crucial for the adhesion of LAB to epithelial cells. The seven strains showing the strongest biofilm formation and/or adhesion represent promising candidates for further investigation in order to develop a probiotic remedy for the treatment of mastitis. Still, their safety for consumers and patients as well as their capability to colonise the udder remain to be investigated in in vivo studies.}, } @article {pmid31294208, year = {2018}, author = {Polyudova, TV and Eroshenko, DV and Korobov, VP}, title = {Plasma, serum, albumin, and divalent metal ions inhibit the adhesion and the biofilm formation of Cutibacterium (Propionibacterium) acnes.}, journal = {AIMS microbiology}, volume = {4}, number = {1}, pages = {165-172}, pmid = {31294208}, issn = {2471-1888}, abstract = {Adhesion and biofilm formation of human skin bacteria C. acnes on plasma, serum and albumin-coated polystyrene or in the presence of these blood components were studied. The proteins which were pre-adsorbed to polystyrene surface or added to the medium simultaneously with bacterial cells reduced C. acnes adhesion and biofilm formation by 2-5 times to compare to the control. The role of calcium, magnesium and zinc on C. acnes attachment was also assessed. Calcium (1 and 10 mM) had the inhibitory effect on C. acnes adhesion, whereas zinc (1 and 10 mM) diminished the biofilm formation of C. acnes. We also observed that C. acnes cells did not bind to erythrocytes. Thus, we suggest that bacteria C. acnes preferably colonize the plasma-poor environment due to the inhibitory effect of blood components, in particular, albumin, calcium, and zinc.}, } @article {pmid31804987, year = {2018}, author = {Miari, M and Rasheed, SS and Haidar-Ahmad, N and Abou Fayad, A and Matar, GM}, title = {Evaluating ginger extract, wild blueberry extract, and polysorbates (PS20, PS80) on Pseudomonas aeruginosa biofilm formation.}, journal = {Journal of infection in developing countries}, volume = {12}, number = {2.1}, pages = {12S}, doi = {10.3855/jidc.10098}, pmid = {31804987}, issn = {1972-2680}, abstract = {INTRODUCTION: Pseudomonas aeruginosa is a biofilm forming pathogen that challenges clinical and industrial settings. Many natural products and surfactants have been screened and valued for their anti-biofilm capacity. In this study we assessed the inhibitory effect and molecular mechanism of action of ginger extract (Zingiber officinale Rosc.), wild blueberry extract (Vaccinium angustifolium), and polysorbates (PS20/PS80) on biofilm formation.

METHODOLOGY: Ginger and wild blueberry extractions were done using ethanol and distilled water, respectively. Hexane and methanol were used for extracts' liquid-liquid portioning. LC-HRMS was performed to obtain extract fractions. Efficacy of the crude extracts, fractions, and polysorbates was assessed on P. aeruginosa PAN14 growth and biofilm. Transcription levels of biofilm encoding genes ndvB, pelC, algC and quorum sensing genes lasI, lasR, rhlI, rhlR were evaluated by RT-qPCR.

RESULTS: Extracts and polysorbates concentrations did not affect P. aeruginosa growth. Biofilm assay showed a reduction in biofilm when 5% ginger, 25% wild blueberry extracts, 0.2% PS20, and 0.25% PS80 were added. LC-HRMS analysis of ginger extract showed abundant gingerol in the hexane layer. Wild blueberry chromatograms showed various constituents differing between their peel and pulp, and pulp extracts. RT-qPCR showed decreased transcription levels of exopolysaccharide and quorum sensing genes with a 363.6 folds reduction in ndvB upon treatment with 25% wild blueberry peel and pulp extract.

CONCLUSION: These results shed light on the mechanism of action of ginger and wild blueberry constituents as well as PS20/80 on P. aeruginosa biofilm formation. Future mouse model experiments are useful to test biofilm inhibition in-vivo.}, } @article {pmid31804983, year = {2018}, author = {Rasheed, SS and Kissoyan, KA and Hadi, U and El-Sabban, M and Matar, GM}, title = {Assessing the effect of micafungin on Pseudomonas aeruginosa biofilm formation using confocal microscopy and gene expression.}, journal = {Journal of infection in developing countries}, volume = {12}, number = {2.1}, pages = {8S}, doi = {10.3855/jidc.10091}, pmid = {31804983}, issn = {1972-2680}, abstract = {INTRODUCTION: 1,3-β-D-glucan of the fungal cell wall and extracellular matrix (ECM) of Candida biofilm is also present as a periplasmic glucan and within the ECM of P. aeruginosa biofilm. Micafungin inhibits the synthesis of β-D-glucans. This project evaluates the effect of micafungin on P. aeruginosa biofilm formation, by determining transcription levels of biofilm formation encoding genes and measuring the thickness of biofilms in treated and untreated samples from BALB/c mice.

METHODOLOGY: Relative gene transcription levels of P. aeruginosa biofilm-encoding pelC, algC, and ndvB genes were assessed by RT-qPCR on treated and untreated samples. Thickness calculation by Z-stacking of treated and untreated biofilms obtained from in vitro and in vivo samples was determined by confocal scanning laser microscopy (CSLM).

RESULTS: Samples from micafungin-treated mice showed decreased pelC, ndvB, and algC transcription levels with values of 260, 74, and 2-fold decreases, respectively. Reduction in biofilms thickness was confirmed with Z-stacking using CSLM that revealed a 16.8% drop in the thickness of biofilms after treatment with micafungin in vitro, and a 64% reduction in thickness post treatment with micafungin in vivo.

CONCLUSION: Micafungin inhibits biofilm formation as measured by decrease in transcription levels of biofilm encoding genes and confocal microscopy. This reflects the events occurring in the course of an acute infection with P. aeruginosa, whereby the administration of micafungin would inhibit subsequent slime production, thus eliminating such barrier that could prevent antibacterial delivery to the core planktonic cells in biofilms.}, } @article {pmid31294188, year = {2017}, author = {Xu, Y and Nagy, A and Bauchan, GR and Xia, X and Nou, X}, title = {Enhanced biofilm formation in dual-species culture of Listeria monocytogenes and Ralstonia insidiosa.}, journal = {AIMS microbiology}, volume = {3}, number = {4}, pages = {774-783}, pmid = {31294188}, issn = {2471-1888}, abstract = {In the natural environments microorganisms coexist in communities as biofilms. Since foodborne pathogens have varying abilities to form biofilms, investigation of bacterial interactions in biofilm formation may enhance our understanding of the persistence of these foodborne pathogens in the environment. Thus the objective of this study was to investigate the interactions between Listeria monocytogenes and Ralstonia insidiosa in dual species biofilms. Biofilm development after 24 h was measured using crystal violet in 96-well microtiter plate. Scanning electron microscopy and cell enumeration were employed after growth on stainless steel coupons. When compared with their single species counterparts, the dual species biofilms exhibited a significant increase in biofilm biomass. The number of L. monocytogenes in co-culture biofilms on stainless steel also increased significantly. However, there was no effect on the biofilm formation of L. monocytogenes when cultured with R. insidiosa separated by a semi-permeable membrane-linked compartment or cultured in R. insidiosa cell-free supernatant, indicating that direct cell-cell contact is critical for this interaction.}, } @article {pmid31294179, year = {2017}, author = {Gomes, LC and Moreira, JMR and Araújo, JDP and Mergulhão, FJ}, title = {Surface conditioning with Escherichia coli cell wall components can reduce biofilm formation by decreasing initial adhesion.}, journal = {AIMS microbiology}, volume = {3}, number = {3}, pages = {613-628}, pmid = {31294179}, issn = {2471-1888}, abstract = {Bacterial adhesion and biofilm formation on food processing surfaces pose major risks to human health. Non-efficient cleaning of equipment surfaces and piping can act as a conditioning layer that affects the development of a new biofilm post-disinfection. We have previously shown that surface conditioning with cell extracts could reduce biofilm formation. In the present work, we hypothesized that E. coli cell wall components could be implicated in this phenomena and therefore mannose, myristic acid and palmitic acid were tested as conditioning agents. To evaluate the effect of surface conditioning and flow topology on biofilm formation, assays were performed in agitated 96-well microtiter plates and in a parallel plate flow chamber (PPFC), both operated at the same average wall shear stress (0.07 Pa) as determined by computational fluid dynamics (CFD). It was observed that when the 96-well microtiter plate and the PPFC were used to form biofilms at the same shear stress, similar results were obtained. This shows that the referred hydrodynamic feature may be a good scale-up parameter from high-throughput platforms to larger scale flow cell systems as the PPFC used in this study. Mannose did not have any effect on E. coli biofilm formation, but myristic and palmitic acid inhibited biofilm development by decreasing cell adhesion (in about 50%). These results support the idea that in food processing equipment where biofilm formation is not critical below a certain threshold, bacterial lysis and adsorption of cell components to the surface may reduce biofilm buildup and extend the operational time.}, } @article {pmid31453228, year = {2017}, author = {Raab, N and Bachelet, I}, title = {Resolving biofilm topography by native scanning electron microscopy.}, journal = {Journal of biological methods}, volume = {4}, number = {2}, pages = {e70}, pmid = {31453228}, issn = {2326-9901}, abstract = {Scanning electron microscopy (SEM) is a powerful tool for structural analysis, but it requires biological samples to undergo lengthy, chemically-complex multi-step preparation procedures, arguably altering some features in the sample. Here we report an ultra-rapid and chemical-free technique for visualizing bacterial biofilms at their native state. Our technique minimizes the time interval from culture to imaging to approximately 20 min, while producing high-resolution images that enable the detection of a variety of topographic features such as bacterial chains, and resolving cells from matrix. We analyzed images obtained from Bacillus subtilis biofilms, demonstrate the usefulness of this technique for multiple types of image analysis, and discuss its potential to be improved and adapted to other types of biological samples.}, } @article {pmid31294148, year = {2017}, author = {Yuyama, KT and Neves, TSPDC and Memória, MT and Tartuci, IT and Abraham, WR}, title = {Aurantiogliocladin inhibits biofilm formation at subtoxic concentrations.}, journal = {AIMS microbiology}, volume = {3}, number = {1}, pages = {50-60}, pmid = {31294148}, issn = {2471-1888}, abstract = {Infections where pathogens are organized in biofilms are difficult to treat due to increased antibiotic resistances in biofilms. To overcome this limitation new approaches are needed to control biofilms. One way is to screen natural products from organisms living in a wet environment. The rational is that these organisms are preferentially threatened by biofilm formation and may have developed strategies to control pathogens in these biofilms. In a screen of fungal isolates obtained from the Harz mountains in Germany several strains have been found producing compounds for the inhibition of biofilms. One of these strains has been identified as Clonostachys candelabrum producing aurantiogliocladin. Biological tests showed aurantiogliocladin as a weak antibiotic which was active against Staphylococcus epidermidis but not S. aureus. Aurantiogliocladin could also inhibit biofilm formation of several of the tested bacterial strains. This inhibition, however, was never complete but biofilm inhibition activity was also found at concentrations below the minimal inhibitory concentrations, e. g. Bacillus cereus with a MIC of 128 µg mL[-1] showed at 32 µg mL[-1] still 37% biofilm inhibition. In agreement with this finding was the observation that aurantiogliocladin was bacteriostatic for the tested bacteria but not bactericidal. Because several closely related toluquinones with different antibiotic activities have been reported from various fungi screening of a chemical library of toluquinones is suggested for the improvement of biofilm inhibition activities.}, } @article {pmid31159129, year = {1996}, author = {Blackman, IC and Frank, JF}, title = {Growth of Listeria monocytogenes as a Biofilm on Various Food-Processing Surfaces.}, journal = {Journal of food protection}, volume = {59}, number = {8}, pages = {827-831}, doi = {10.4315/0362-028X-59.8.827}, pmid = {31159129}, issn = {1944-9097}, abstract = {The objective of this research was to determine the ability of Listeria monocytogenes to grow as a biofilm on various food-processing surfaces including stainless steel, Teflon[®], nylon, and polyester floor sealant. Each of these surfaces was able to support biofilm formation when incubation was at 21°C in Trypticase soy broth (TSB). Biofilm formation was greatest on polyester floor sealant (40% of surface area covered after 7 days of incubation) and least on nylon (3% coverage). The use of chemically defined minimal medium resulted in a lack of biofilm formation on polyester floor sealant, and reduced biofilm levels on stainless steel. Biofilm formation was reduced with incubation at 10°C, but Teflon[®] and stainless steel still allowed 23 to 24% coverage after incubation in TSB for 18 days. Biofilm growth of L. monocytogenes was sufficient to provide a substantial risk of this pathogen contaminating the food-processing plant environment if wet surfaces are not maintained in a sanitary condition.}, } @article {pmid31121771, year = {1995}, author = {Kim, KY and Frank, JF}, title = {Effect of Nutrients on Biofilm Formation by Listeria monocytogenes on Stainless Steel.}, journal = {Journal of food protection}, volume = {58}, number = {1}, pages = {24-28}, doi = {10.4315/0362-028X-58.1.24}, pmid = {31121771}, issn = {1944-9097}, abstract = {The effect of nutrients on the development of biofilms by Listeria monocytogenes was investigated using semicontinuous culture in a chemically defined minimal medium (modified Welshimer's broth, MWB). Inoculated slides were used for the development of biofilms for 12 days at 21°C under various nutrient conditions. Biofilms were quantified by measuring the percentage of area covered by cells, using computerized image analysis. MWB allowed slow development of Listeria monocytogenes biofilms. Glucose levels between 1 and 20 g/l did not affect biofilm development. A reduction or increase in phosphate level from that occurring in MWB (37.52 g/l) reduced biofilm development. The degree to which biofilms initially developed was associated with amino acid concentration within the range of 0.12 to 6 g/l; however, after 12 days of incubation, the amount of biofilm produced was not affected by amino acid concentration. Replacement of amino acids in MWB with tryptone initially enhanced biofilm development, but the effect was not significant after 12 days of incubation. Of five carbohydrates tested, mannose and trehalose enhanced biofilm development.}, } @article {pmid31113117, year = {1993}, author = {Sasahara, KC and Zottola, EA}, title = {Biofilm Formation by Listeria monocytogenes Utilizes a Primary Colonizing Microorganism in Flowing Systems.}, journal = {Journal of food protection}, volume = {56}, number = {12}, pages = {1022-1028}, doi = {10.4315/0362-028X-56.12.1022}, pmid = {31113117}, issn = {1944-9097}, abstract = {Listeria monocytogenes serotype 3a and Pseudomonas fragi ATCC 4973 were examined for attachment capability and biofilm development on glass coverslips under flowing systems. Tryptic soy broth supplemented with yeast extract was the growth medium. A continuous flow slide chamber was developed for in situ observations using phase-contrast microscopy. Glass coverslips were examined by epifluorescent and scanning electron microscopy for biofilm formation. The ultrastructure of attached test organisms was examined for the presence of exopolymers using transmission electron microscopy. In pure cultures, attachment of L. monocytogenes to glass coverslips was sparse, while P. fragi accumulated on glass coverslips as a confluent layer of cells. When L. monocytogenes was grown in mixed culture with P. fragi , an exopolymer-producing microorganism, attachment and microcolony formation by L. monocytogenes was enhanced. Results suggest that under flowing conditions the presence of an exopolymer-producing microorganism may be more important than hydrophobicity, surface charge, or flagellar movement in attachment of L. monocytogenes to inert surfaces.}, } @article {pmid31113053, year = {1993}, author = {Ronner, AB and Wong, ACL}, title = {Biofilm Development and Sanitizer Inactivation of Listeria monocytogenes and Salmonella typhimurium on Stainless Steel and Buna-n Rubber.}, journal = {Journal of food protection}, volume = {56}, number = {9}, pages = {750-758}, doi = {10.4315/0362-028X-56.9.750}, pmid = {31113053}, issn = {1944-9097}, abstract = {Biofilm formation by seven strains of Listeria monocytogenes and one strain of Salmonella typhimurium on stainless steel and Buna-n rubber was examined under two nutrient conditions. The type of surface, nutrient level, and organism influenced biofilm development and production of extracellular materials. Buna-n had a strong bacteriostatic effect on L. monocytogenes , and biofilm formation on Buna-n under low nutrient conditions was reduced for four of the seven strains tested. Buna-n was less bacteriostatic toward S. typhimurium . It inhibited the growth of several other pathogens to varying degrees. An ethylene propylene diamine monomer rubber was less inhibitory than Buna-n, and Viton rubber had no effect. The effectiveness of sanitizers on biofilm bacteria was examined. Biofilms were challenged with four types of detergent and nondetergent sanitizers. Resistance to sanitizers was strongly influenced by the type of surface. Bacterial biofilm populations on stainless steel were reduced 3-5 log by all the sanitizers, but those on Buna-n were resistant to these sanitizers and were reduced less than 1-2 log. In contrast, planktonic (suspended) bacteria were reduced 7-8 log by these sanitizers. Chlorine and anionic acid sanitizers generally removed extracellular materials from biofilms better than iodine and quaternary ammonium detergent sanitizers. Scanning electron microscopy demonstrated that biofilm cells and extracellular matrices could remain on sanitized biofilm cells and extracellular matrices could remain surfaces from which no viable cells were recovered.}, } @article {pmid31113100, year = {1993}, author = {Wirtanen, G and Mattila-Sandholm, T}, title = {Epifluorescence Image Analysis and Cultivation of Foodborne Biofilm Bacteria Grown on Stainless Steel Surfaces.}, journal = {Journal of food protection}, volume = {56}, number = {8}, pages = {678-683}, doi = {10.4315/0362-028X-56.8.678}, pmid = {31113100}, issn = {1944-9097}, abstract = {In this study, biofilm was grown on stainless steel surfaces (AISI 304) for 2, 5, and 10 d at 25°C in slime broth inoculated with the food spoilage microbes Bacillus subtilis , Listeria monocytogenes , Pediococcus pentosaceus , and Pseudomonas fragi . The biofilm developing on steel surfaces were investigated using conventional plating, quantitative glycocalyx determination, and epifluorescence microscopy with image analysis. The results showed that B. subtilis and P. fragi could easily be cultivated after 2 d growth. After a growth period of 10 d, the cells were difficult to cultivate from the surface, and the growth was detected better by microscopy. L. monocytogenes , on the other hand, could easily be detected by cultivation after 2, 5, and 10 d. The greatest amount of slime was produced by P. pentosaceus , as was also shown by epifluorescence microscopy.}, } @article {pmid31113042, year = {1993}, author = {Ren, TJ and Frank, JF}, title = {Susceptibility of Starved Planktonic and Biofilm Listeria monocytogenes to Quaternary Ammonium Sanitizer as Determined by Direct Viable and Agar Plate Counts.}, journal = {Journal of food protection}, volume = {56}, number = {7}, pages = {573-576}, doi = {10.4315/0362-028X-56.7.573}, pmid = {31113042}, issn = {1944-9097}, abstract = {Effective food plant cleaning procedures remove microbial nutrients from surfaces, which could result in contaminating bacteria being subject to a starvation microenvironment. This research investigated the effect of starvation on the susceptibility of Listeria monocytogenes to benzalkonium chloride (BAC). Cells were starved in phosphate buffer at 21°C for 4 d. Biofilm and planktonic listeriae reacted differently to starvation. When cells were grown in tryptic soy broth (TSB), starvation reduced the susceptibility of planktonic cells to BAC by 2.3- to 4.7-fold but had no effect on the susceptibility of biofilm cells. Planktonic cells grown in diluted TSB were 390 times more resistant than normal TSB-grown cells, but when these cells were starved, they lost their increased resistance. This phenomenon was not observed with biofilm cells. Increased resistance of listeriae grown in diluted TSB was associated with dilution of the salt/buffer components of the medium. Sanitizer-treated cells were enumerated by using tryptic soy agar-yeast extract pour plates and by a direct viable count method. Results indicate that some cells exposed to BAC were not detected by the plate count procedure but were still viable.}, } @article {pmid31088936, year = {2019}, author = {Tobudic, S and Kern, S and Kussmann, M and Forstner, C and Burgmann, H}, title = {Effect of Peritoneal Dialysis Fluids on Activity of Teicoplanin Against Methicillin-Resistant Staphylococcus aureus Biofilm.}, journal = {Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis}, volume = {39}, number = {3}, pages = {293-294}, doi = {10.3747/pdi.2018.00168}, pmid = {31088936}, issn = {1718-4304}, mesh = {Biofilms/drug effects ; Cohort Studies ; Dialysis Solutions/*adverse effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Microbial Sensitivity Tests ; Peritoneal Dialysis/*adverse effects/methods ; Peritonitis/*drug therapy/etiology/*microbiology ; Prognosis ; Retrospective Studies ; Risk Assessment ; Staphylococcal Infections/*drug therapy/etiology ; Teicoplanin/*therapeutic use ; Treatment Outcome ; }, } @article {pmid31088182, year = {2019}, author = {Čabarkapa, I and Čolović, R and Đuragić, O and Popović, S and Kokić, B and Milanov, D and Pezo, L}, title = {Anti-biofilm activities of essential oils rich in carvacrol and thymol against Salmonella Enteritidis.}, journal = {Biofouling}, volume = {35}, number = {3}, pages = {361-375}, doi = {10.1080/08927014.2019.1610169}, pmid = {31088182}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cymenes ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Oils, Volatile/*pharmacology ; Salmonella enteritidis/*drug effects/physiology ; Thymol/*pharmacology ; }, abstract = {The aim of the present study was to determine the bioactive compounds in four essential oils (EO's) from Origanum heracleoticum, Origanum vulgare, Thymus vulgaris and Thymus serpyllum and to assess their antimicrobial and anti-biofilm activity against Salmonella Enteritidis. Strains were previously characterized depending on the expression of the extracellular matrix components cellulose and curli fimbriae as rdar (red, dry and rough) and bdar morphotype (brown, dry and rough). This study revealed that the EO's and EOC's (carvacrol and thymol) investigated showed inhibition of biofilm formation at sub-minimum inhibitory concentration. Comparing the efficacy of EO's and EOC's in the inhibition of biofilm formation between the strains with different morphotype (rdar and bdar) did not show a statistically significant difference. Results related to the effectiveness of EO's and EOC's (the essential oil components, carvacrol and thymol) on eradication of preformed 48 h old biofilms indicated that biofilm reduction occurred in a dose-dependent manner over time.}, } @article {pmid31088179, year = {2019}, author = {Bernard, C and Lemoine, V and Hoogenkamp, MA and Girardot, M and Krom, BP and Imbert, C}, title = {Candida albicans enhances initial biofilm growth of Cutibacterium acnes under aerobic conditions.}, journal = {Biofouling}, volume = {35}, number = {3}, pages = {350-360}, doi = {10.1080/08927014.2019.1608966}, pmid = {31088179}, issn = {1029-2454}, mesh = {*Biofilms ; *Candida albicans ; Humans ; *Microbial Interactions ; Propionibacterium acnes/*physiology ; }, abstract = {Candida albicans and Cutibacterium acnes are opportunistic pathogens that co-colonize the human body. They are involved in biofilm-related infections of implanted medical devices. The objective of this study was to evaluate the ability of these species to interact and form polymicrobial biofilms. SEM imaging and adhesion assays showed that C. acnes adhesion to C. albicans did not have a preference for a specific morphological state of C. albicans; bacteria adhered to both hyphal and yeast forms of C. albicans. C. albicans did not influence growth of C. acnes under anaerobic growth conditions, however under aerobic growth condition, C. albicans enhanced early C. acnes biofilm formation. This favorable impact of C. albicans was not mediated by secreted compounds accumulating in the medium, but required the presence of metabolically active C. albicans. The ability of these microorganisms to interact together could modulate the physiopathology of infections.}, } @article {pmid31087992, year = {2019}, author = {Fu, KM and Liao, MH and Zhou, HT and Fu, C and Jiang, S and Qiu, FG and Cao, XQ}, title = {[Operation Characteristics of the Biofilm CANON Reactor During the Temperature Reduction Process].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {40}, number = {3}, pages = {1412-1418}, doi = {10.13227/j.hjkx.201808184}, pmid = {31087992}, issn = {0250-3301}, abstract = {The focus of this paper, was low temperature, high ammonia nitrogen wastewater. The operation characteristics of the biofilm CANON process during the temperature reduction process were determined, by continuously adjusting different operating conditions. The aim was to explore the methods needed for the CANON process to obtain stable shortcut nitrification and a good nitrogen removal effect, when the influent NH4[+]-N concentration is high and the temperature low. The results showed that, ① compared with the biofilm CANON reactor temperature changing from medium to low temperature directly (30℃±1℃→19℃), it was more conducive to adapt the nitrogen-removing bacteria to the low-temperature environment, while the temperature was gradually lowered. Moreover, the extent of each reduction should be minimized. Besides, the operating conditions should be adjusted to ensure the nitrogen removal effect. ② The temperature was gradually reduced to about 19℃ after 25 d, and then decreased to about 15℃ after another 18 d. The NH4[+]-N and TN removal rates could be respectively stable at 90% and 70% over a long period of time. The TN removal rate and removal load could still reach 72.52% and 0.78 kg·(m[3]·d)[-1], respectively, even when the temperature dropped to 12℃. ③ When adapting biological CANON sludge during the temperature reduction process, shortcut nitrification should be given priority. A stable shortcut nitrification effect should be obtained by maintaining a certain concentration of residual NH4[+]-N, and by strictly controlling the DO concentration to restrain NOB activity.}, } @article {pmid31087603, year = {2019}, author = {Zhu, L and Gong, T and Wood, TL and Yamasaki, R and Wood, TK}, title = {σ54 -Dependent regulator DVU2956 switches Desulfovibrio vulgaris from biofilm formation to planktonic growth and regulates hydrogen sulfide production.}, journal = {Environmental microbiology}, volume = {21}, number = {10}, pages = {3564-3576}, doi = {10.1111/1462-2920.14679}, pmid = {31087603}, issn = {1462-2920}, support = {//Pennsylvania State University/International ; //Dow Chemical Company/International ; }, mesh = {Bacterial Proteins ; Biofilms/growth & development ; Desulfovibrio vulgaris/genetics/*metabolism ; Electron Transport ; Gene Expression Regulation, Bacterial ; Hydrogen Sulfide/*metabolism ; }, abstract = {Microbiologically influenced corrosion causes $100 billion in damage per year, and biofilms formed by sulfate-reducing bacteria (SRB) are the major culprit. However, little is known about the regulation of SRB biofilm formation. Using Desulfovibrio vulgaris as a model SRB organism, we compared the transcriptomes of biofilm and planktonic cells and identified that the gene for σ54 -dependent regulator DVU2956 is repressed in biofilms. Utilizing a novel promoter that is primarily transcribed in biofilms (Pdvu0304), we found production of DVU2956 inhibits biofilm formation by 70%. Corroborating this result, deleting dvu2956 increased biofilm formation, and this biofilm phenotype could be complemented. By producing proteins in biofilms from genes controlled by DVU2956 (dvu2960 and dvu2962), biofilm formation was inhibited almost completely. A second round of RNA-seq for the production of DVU2956 revealed DVU2956 influences electron transport via an Hmc complex (high-molecular-weight cytochrome c encoded by dvu0531-dvu0536) and the Fe-only hydrogenase (encoded by dvu1769, hydA and dvu1770, hydB) to control H2 S production. Corroborating these results, producing DVU2956 in biofilms decreased H2 S production by half, deleting dvu2956 increased H2 S production by 131 ± 5%, and producing DVU2956 in the dvu2956 strain reduced H2 S production. Therefore, DVU2956 maintains SRB in the planktonic state and reduces H2 S formation.}, } @article {pmid31087370, year = {2019}, author = {Banerjee, A and Bardhan, R and Chowdhury, M and Joardar, SN and Isore, DP and Batabyal, K and Dey, S and Sar, TK and Bandyopadhyay, S and Dutta, TK and Samanta, I}, title = {Characterization of beta-lactamase and biofilm producing Enterobacteriaceae isolated from organized and backyard farm ducks.}, journal = {Letters in applied microbiology}, volume = {69}, number = {2}, pages = {110-115}, doi = {10.1111/lam.13170}, pmid = {31087370}, issn = {1472-765X}, support = {BT/PR16149/NER/95/85/2015//Department of Biotechnology, Government of India/ ; 1G-25/2016//Department of Science & Technology and Biotechnology, Government of West Bengal/ ; }, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Drug Resistance, Bacterial ; Ducks/*microbiology ; Enterobacteriaceae/enzymology/genetics/isolation & purification/*physiology ; Enterobacteriaceae Infections/epidemiology/microbiology/*veterinary ; Farms ; Female ; India/epidemiology ; Male ; Phenotype ; Poultry Diseases/epidemiology/*microbiology ; beta-Lactamases/*genetics ; }, abstract = {This study was undertaken to detect the occurrence of beta-lactamase and biofilm producing Enterobacteriaceae in healthy ducks. A total 202 cloacal swabs were collected from ducks kept in organized (n = 92) and backyard (n = 110) farms in West Bengal (India). The ducks had no history of antibiotic intake. Among the 87 phenotypically beta-lactamase producing Escherichia coli, 19 (17·43%), 6 (5·05%) and 15 (13·76%) isolates possessed blaTEM , blaSHV and blaCTX-M respectively. Whereas, 5 (38·46%) Salmonella isolates were found to harbour blaCTX-M . In K. pneumoniae 10 (33·33%), 3 (13·33%), 4 (13·33%) isolates possessed blaTEM , blaSHV and blaCTX-M respectively. The sequences of selected PCR products were found 98% cognate with blaCTX-M-9, blaSHV-12 and blaTEM-1 . Beta-lactamase producing E. coli isolates belonged to 14 different serogroups such as O1, O2, O3, O5, O7, O8, O35, O83, O84, O88, O119, O128, O145 and O157. Moreover, 87 E. coli (79·82%), six Samonella (46·15%) and 13 K. pneumoniae (43·33%) isolates were detected as AmpC producers possessing blaAmpC . Majority of E. coli (46·79%), Salmonella (46·15%) and K. pneumoniae (70%) isolates were detected as biofilm producers and possessed the associated genes (csgA, sdiA, rcsA, rpoS). Significantly higher occurrence of beta-lactamase and biofilm producing Enterobacteriaceae isolates was detected in backyard ducks than organized farms. SIGNIFICANCE AND IMPACT OF THE STUDY: Consumption of antibiotic through feed or during therapy is considered as potential reason for generation of antimicrobial resistant bacteria in birds. This study provides valuable evidence that exposure to contaminated environment may be an additional source for generation of antimicrobial resistant bacteria in backyard ducks. The backyard ducks are reared by marginal farmers in India who cannot offer antibiotics to them either through feed or during therapy due to high cost. The study also reveals a significant correlation between biofilm formation and possession of antimicrobial resistance genes in the bacterial isolates from the ducks.}, } @article {pmid31085909, year = {2019}, author = {Dos Santos, DMS and Pires, JG and Silva, AB and Salomão, PMA and Buzalaf, MAR and Magalhães, AC}, title = {Protective Effect of 4% Titanium Tetrafluoride Varnish on Dentin Demineralization Using a Microcosm Biofilm Model.}, journal = {Caries research}, volume = {53}, number = {5}, pages = {576-583}, doi = {10.1159/000499317}, pmid = {31085909}, issn = {1421-976X}, mesh = {Animals ; Biofilms/*drug effects ; Cariostatic Agents ; Cattle ; Dentin/*drug effects/pathology ; Fluorides/*therapeutic use ; Fluorides, Topical ; Humans ; In Vitro Techniques ; Lactic Acid ; Lactobacillus/drug effects ; Sodium Fluoride/therapeutic use ; Streptococcus mutans/drug effects ; Titanium/*therapeutic use ; Tooth Demineralization/*prevention & control ; }, abstract = {This study evaluated the effect of titanium tetrafluoride (TiF4) varnish on the development of dentin carious lesions. Bovine root dentin samples were treated for 6 h with: (A) 4% TiF4 varnish (2.45% F); (B) 5.42% sodium fluoride (NaF) varnish (2.45% F); (C) 2% chlorhexidine (CHX) gel - positive control; (D) placebo varnish; or (E) untreated - negative control (n = 4 × biological triplicate, n = 12). Treated dentin samples were exposed to human saliva mixed with McBain saliva (1:50) for the first 8 h in 24-well plates. Thereafter, the medium was removed, and McBain saliva containing 0.2% sucrose was applied for 16 h. From days 2 to 5, McBain saliva with sucrose was replaced daily (37°C, 5% CO2). The demineralization was measured using transverse microradiography, while the effect on biofilm was analyzed using viability, extracellular polysaccharide (EPS), and lactic acid production assays. The data were statistically analyzed (p < 0.05). All treatments (fluorides and CHX) significantly reduced the biofilm viability compared to placebo varnish and negative control. However, none of them was able to reduce the colony-forming unit counting for total microorganism, total streptococci, and Streptococcus mutans. NaF significantly reduced the number of Lactobacillus sp. compared to negative control. No effect was seen on lactic acid production neither on EPS synthesis, except that CHX significantly reduced the amount of insoluble EPS. Both fluorides were able to reduce dentin demineralization compared to placebo varnish and negative control; TiF4 had a better effect in reducing mineral loss and lesion depth than NaF. Therefore, TiF4 varnish has the best protective effect on dentin carious lesion formation using this model.}, } @article {pmid31085695, year = {2019}, author = {Matysik, A and Kline, KA}, title = {Streptococcus pyogenes Capsule Promotes Microcolony-Independent Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31085695}, issn = {1098-5530}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Extracellular Matrix/metabolism ; Humans ; Streptococcal Infections/*microbiology ; Streptococcus pyogenes/metabolism/*pathogenicity/*physiology ; }, abstract = {Biofilms play an important role in the pathogenesis of group A streptococcus (GAS), a Gram-positive pathogen responsible for a wide range of infections and with a significant public health impact. Although most GAS serotypes are able to form biofilms, there is a large amount of heterogeneity between individual strains in biofilm formation, as measured by standard crystal violet assays. It is generally accepted that biofilm formation includes the initial adhesion of bacterial cells to a surface followed by microcolony formation, biofilm maturation, and extensive production of extracellular matrix that links together proliferating cells and provides a scaffold for the three-dimensional (3D) biofilm structure. However, our studies show that for GAS strain JS95, microcolony formation is not an essential step in static biofilm formation, and instead, biofilm can be effectively formed from slow-growing or nonreplicating late-exponential- or early-stationary-phase planktonic cells via sedimentation and fixation of GAS chains. In addition, we show that the GAS capsule specifically contributes to the alternative sedimentation-initiated biofilms. Microcolony-independent sedimentation biofilms are similar in morphology and 3D structure to biofilms initiated by actively dividing planktonic bacteria. We conclude that GAS can form biofilms by an alternate noncanonical mechanism that does not require transition from microcolony formation to biofilm maturation and which may be obscured by biofilm phenotypes that arise via the classical biofilm maturation processes.IMPORTANCE The static biofilm assay is a common tool for easy biomass quantification of biofilm-forming bacteria. However, Streptococcus pyogenes biofilm formation as measured by the static assay is strain dependent and yields heterogeneous results for different strains of the same serotype. In this study, we show that two independent mechanisms, for which the protective capsule contributes opposing functions, may contribute to static biofilm formation. We propose that separation of these mechanisms for biofilm formation might uncover previously unappreciated biofilm phenotypes that may otherwise be masked in the classic static assay.}, } @article {pmid31085409, year = {2019}, author = {Wan, D and Li, Q and Chen, J and Niu, Z and Liu, Y and Li, H and Xiao, S}, title = {Simultaneous bio-electrochemical reduction of perchlorate and electro-disinfection in a novel Moving-Bed Biofilm Reactor (MBBR) based on proton-exchange membrane electrolysis.}, journal = {The Science of the total environment}, volume = {679}, number = {}, pages = {288-297}, doi = {10.1016/j.scitotenv.2019.04.441}, pmid = {31085409}, issn = {1879-1026}, mesh = {*Biofilms ; *Bioreactors ; Disinfection/instrumentation/*methods ; Electrochemical Techniques/instrumentation/*methods ; Electrolysis ; Membranes, Artificial ; Oxidation-Reduction ; Perchlorates/*chemistry ; *Protons ; }, abstract = {A novel Moving-Bed Biofilm Reactor (MBBR), based on proton-exchange membrane electrolysis, was developed and tested for perchlorate transformation. The bacteria growing on the carrier in the cathode chamber could use in situ-generated hydrogen to reduce perchlorate to chloride via electrolysis; the resulting chloride ions and chloride ions in raw water were then oxidized into chlorine by anode reaction to disinfect the final effluent and improve water quality. For a ClO4[-] concentration of 10.00 ± 0.08 mg/L in the influent, at hydraulic retention times (HRTs) of 4.0, 2.0, and 1.5 h, the optimal applied currents (OACs) were 130, 240, and 270 mA, with a corresponding removal efficiencies of 99.90 ± 0.21, 96.70 ± 0.36, and 78.50 ± 0.24%, respectively. Active chlorine concentration was in the range of 0.063-0.096 mg/L, contributing to simultaneous electro-disinfection. Along the water flow direction, OH[-] generated by the cathode could be neutralized in the anode chamber; thus, the final effluent pH was kept a balance with the influent pH. Proteobacteria, Bacteroidetes, and Firmicutes were the dominant bacteria in the MBBR. The maximum value of current efficiency (13.32 ± 0.69%) was obtained at 100 mA and an HRT of 4.0 h, which was in accordance with the abundance of Thauera.}, } @article {pmid31085405, year = {2019}, author = {Wall, G and Montelongo-Jauregui, D and Vidal Bonifacio, B and Lopez-Ribot, JL and Uppuluri, P}, title = {Candida albicans biofilm growth and dispersal: contributions to pathogenesis.}, journal = {Current opinion in microbiology}, volume = {52}, number = {}, pages = {1-6}, pmid = {31085405}, issn = {1879-0364}, support = {R01 AI119554/AI/NIAID NIH HHS/United States ; R01 AI141794/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; R21 HD097480/HD/NICHD NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*growth & development/*pathogenicity ; Candidiasis/*microbiology/*physiopathology ; Humans ; Virulence ; }, abstract = {The fungal species Candida albicans is most frequently associated with biofilm formation in immune-compromised and medically compromised patients, and it is now firmly established that biofilm formation represents a major virulence factor during candidiasis. A growing body of evidence has demonstrated that C. albicans biofilm development is a highly regulated and coordinated process, where adhesive interactions, morphogenetic conversions, and consortial behavior play significant roles. Cells within the biofilms are protected from environmental stresses including host immune defenses and antifungal treatment, which carries important clinical consequences for the treatment of biofilm-associated infections. Dispersal of cells from biofilms represents one of the hallmarks of the biofilm life-style, and in the case of C. albicans dispersed cells are responsible for candidemia and dissemination leading to the establishment of invasive disease.}, } @article {pmid31085344, year = {2019}, author = {Girish, VM and Liang, H and Aguilan, JT and Nosanchuk, JD and Friedman, JM and Nacharaju, P}, title = {Anti-biofilm activity of garlic extract loaded nanoparticles.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {20}, number = {}, pages = {102009}, pmid = {31085344}, issn = {1549-9642}, support = {P01 HL110900/HL/NHLBI NIH HHS/United States ; P30 CA013330/CA/NCI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Disulfides ; Garlic/*chemistry ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Plant Extracts/*pharmacology ; Sulfinic Acids/pharmacology ; }, abstract = {The emergence and widespread distribution of multi-drug resistant bacteria are considered as a major public health concern. The inabilities to curb severe infections due to antibiotic resistance have increased healthcare costs as well as patient morbidity and mortality. Bacterial biofilms formed by drug-resistant bacteria add additional challenges to treatment. This study describes a solgel based nanoparticle system loaded with garlic extract (GE-np) that exhibits: i) slow and sustained release of garlic components; ii) stabilization of the active components; and iii) significant enhancement of antimicrobial and antibiofilm activity relative to the free garlic extract. Also, GE-np were efficient in penetrating and disrupting the well-established methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Overall, the study suggests that GE-np might be a promising candidate for the treatment of chronic infections due to biofilm forming drug-resistant bacteria.}, } @article {pmid31083437, year = {2019}, author = {Nagel, C and Machulla, A and Zahn, S and Soppa, J}, title = {Several One-Domain Zinc Finger µ-Proteins of Haloferax Volcanii Are Important for Stress Adaptation, Biofilm Formation, and Swarming.}, journal = {Genes}, volume = {10}, number = {5}, pages = {}, pmid = {31083437}, issn = {2073-4425}, mesh = {Adaptation, Physiological ; Archaeal Proteins/*genetics ; Bile Acids and Salts/pharmacology ; Biofilms ; Gene Deletion ; Gene Expression Regulation, Archaeal ; Haloferax volcanii/*genetics/physiology ; Stress, Physiological ; Zinc Fingers/*genetics ; }, abstract = {Zinc finger domains are highly structured and can mediate interactions to DNA, RNA, proteins, lipids, and small molecules. Accordingly, zinc finger proteins are very versatile and involved in many biological functions. Eukaryotes contain a wealth of zinc finger proteins, but zinc finger proteins have also been found in archaea and bacteria. Large zinc finger proteins have been well studied, however, in stark contrast, single domain zinc finger µ-proteins of less than 70 amino acids have not been studied at all, with one single exception. Therefore, 16 zinc finger µ-proteins of the haloarchaeon Haloferax volcanii were chosen and in frame deletion mutants of the cognate genes were generated. The phenotypes of mutants and wild-type were compared under eight different conditions, which were chosen to represent various pathways and involve many genes. None of the mutants differed from the wild-type under optimal or near-optimal conditions. However, 12 of the 16 mutants exhibited a phenotypic difference under at least one of the four following conditions: Growth in synthetic medium with glycerol, growth in the presence of bile acids, biofilm formation, and swarming. In total, 16 loss of function and 11 gain of function phenotypes were observed. Five mutants indicated counter-regulation of a sessile versus a motile life style in H. volcanii. In conclusion, the generation and analysis of a set of deletion mutants demonstrated the high importance of zinc finger µ-proteins for various biological functions, and it will be the basis for future mechanistic insight.}, } @article {pmid31083366, year = {2019}, author = {Foster, LL and Yusa, SI and Kuroda, K}, title = {Solution-Mediated Modulation of Pseudomonas aeruginosa Biofilm Formation by a Cationic Synthetic Polymer.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {31083366}, issn = {2079-6382}, support = {U01DE023771//National Institutes of Health/ ; DGE-1315231//National Science Graduate Research Fellowship/ ; }, abstract = {Bacterial biofilms and their associated infections are a continuing problem in the healthcare community. Previous approaches utilizing anti-biofilm coatings suffer from short lifetimes, and their applications are limited to surfaces. In this research, we explored a new approach to biofilm prevention based on the hypothesis that changing planktonic bacteria behavior to result in sub-optimal biofilm formation. The behavior of planktonic Pseudomonas aeruginosa exposed to a cationic polymer was characterized for changes in growth behavior and aggregation behavior, and linked to resulting P. aeruginosa biofilm formation, biomass, viability, and metabolic activity. The incubation of P. aeruginosa planktonic bacteria with a cationic polymer resulted in the aggregation of planktonic bacteria, and a reduction in biofilm development. We propose that cationic polymers may sequester planktonic bacteria away from surfaces, thereby preventing their attachment and suppressing biofilm formation.}, } @article {pmid31082673, year = {2019}, author = {Guo, X and Li, B and Zhao, R and Zhang, J and Lin, L and Zhang, G and Li, RH and Liu, J and Li, P and Li, Y and Li, XY}, title = {Performance and bacterial community of moving bed biofilm reactors with various biocarriers treating primary wastewater effluent with a low organic strength and low C/N ratio.}, journal = {Bioresource technology}, volume = {287}, number = {}, pages = {121424}, doi = {10.1016/j.biortech.2019.121424}, pmid = {31082673}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Nitrogen ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {A laboratory-scale sequencing batch reactor (SBR) and two moving bed biofilm reactors (MBBRs) with different types of biocarriers were operated to treat the effluent of chemically enhanced primary sedimentation (CEPS). Due to the low organic strength and low carbon/nitrogen ratio of the CEPS effluent, COD and NH4[+]-N were effectively removed by the MBBRs but not by the SBR. Of the two MBBRs, MBBR2 filled with LEVAPOR biocarrier cubes performed even better than MBBR1 filled with K3 polystyrene biocarriers. The continuous decline of the sludge concentration in the SBR and the high and stable biomass content in MBBR2 contributed to their performances. High-throughput sequencing analysis showed that the reactors had selective effects on the bacterial community structure. Principal coordinate analysis indicated the different dynamic successions in the three reactors. Network analysis showed different community composition and diversity that were highly suggestive of different bacterial interactions among the three bioreactors.}, } @article {pmid31081821, year = {2019}, author = {Panariello, BHD and Garcia, BA and Duarte, S}, title = {Daily Phototherapy with Red Light to Regulate Candida albicans Biofilm Growth.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {146}, pages = {}, doi = {10.3791/59326}, pmid = {31081821}, issn = {1940-087X}, mesh = {Biofilms/*growth & development/*radiation effects ; Candida albicans/cytology/*physiology/*radiation effects ; Extracellular Space/metabolism/radiation effects ; Fungal Polysaccharides/chemistry/metabolism ; Kinetics ; *Light ; Solubility ; }, abstract = {Here, we present a protocol to assess the outcomes of per diem red light treatment on the growth of Candida albicans biofilm. To increase the planktonic growth of C. albicans SN425, the inoculums grew on Yeast Nitrogen Base media. For biofilm formation, RPMI 1640 media, which have high concentrations of amino acids, were applied to help biofilm growth. Biofilms of 48 h were treated twice a day for a period of 1 min with a non-coherent light device (red light; wavelength = 635 nm; energy density = 87.6 J·cm[-2]). As a positive control (PC), 0.12% chlorhexidine (CHX) was applied, and as a negative control (NC), 0.89% NaCl was applied to the biofilms. Colony forming units (CFU), dry-weight, soluble and insoluble exopolysaccharides were quantified after treatments. Briefly, the protocol presented here is simple, reproducible and provides answers regarding viability, dry-weight and extracellular polysaccharide amounts after red light treatment.}, } @article {pmid31080568, year = {2019}, author = {Mai, HN and Hong, SH and Kim, SH and Lee, DH}, title = {Effects of different finishing/polishing protocols and systems for monolithic zirconia on surface topography, phase transformation, and biofilm formation.}, journal = {The journal of advanced prosthodontics}, volume = {11}, number = {2}, pages = {81-87}, pmid = {31080568}, issn = {2005-7806}, abstract = {PURPOSE: The purpose of this study was to evaluate the effects of various protocols and systems for finishing and polishing monolithic zirconia on surface topography, phase transformation, and bacterial adhesion.

MATERIALS AND METHODS: Three hundred monolithic zirconia specimens were fabricated and then treated with three finishing and polishing systems (Jota [JO], Meisinger [ME], and Edenta [ED]) using four surface treatment protocols: coarse finishing alone (C); coarse finishing and medium polishing (CM); coarse finishing and fine polishing (CF); and coarse finishing, medium polishing, and fine polishing (CMF). Surface roughness, crystal phase transformation, and bacterial adhesion were evaluated using atomic force microscopy, X-ray diffraction, and streptococcal biofilm formation assay, respectively. One-way and two-way analysis of variance with Tukey post hoc tests were used to analyze the results (α=.05).

RESULTS: In this study, the surface treatment protocols and systems had significant effects on the resulting roughness. The CMF protocol produced the lowest roughness values, followed by CM and CF. Use of the JO system produced the lowest roughness values and the smallest biofilm mass, while the ME system produced the smallest partial transformation ratio. The ED group exhibited the highest roughness values, biofilm mass, and partial transformation ratio.

CONCLUSION: Stepwise surface treatment of monolithic zirconia, combined with careful polishing system selection, is essential to obtaining optimal microstructural and biological surface results.}, } @article {pmid31079197, year = {2020}, author = {Pillot, G and Davidson, S and Auria, R and Combet-Blanc, Y and Godfroy, A and Liebgott, PP}, title = {Production of Current by Syntrophy Between Exoelectrogenic and Fermentative Hyperthermophilic Microorganisms in Heterotrophic Biofilm from a Deep-Sea Hydrothermal Chimney.}, journal = {Microbial ecology}, volume = {79}, number = {1}, pages = {38-49}, pmid = {31079197}, issn = {1432-184X}, support = {PEPS-ExoMod 2016//Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique/ ; 1166-39417//European Regional Development Fund/ ; }, mesh = {Acetates/metabolism ; Archaea/*chemistry/classification/genetics/*physiology ; Biofilms ; Electricity ; Electrodes/microbiology ; Fermentation ; Hydrogen/metabolism ; Hydrothermal Vents/*microbiology ; Oxidation-Reduction ; Pyruvic Acid/metabolism ; }, abstract = {To study the role of exoelectrogens within the trophic network of deep-sea hydrothermal vents, we performed successive subcultures of a hyperthermophilic community from a hydrothermal chimney sample on a mix of electron donors in a microbial fuel cell system. Electrode (the electron acceptor) was swapped every week to enable fresh development from spent media as inoculum. The MFC at 80 °C yielded maximum current production increasing from 159 to 247 mA m[-2] over the subcultures. The experiments demonstrated direct production of electric current from acetate, pyruvate, and H2 and indirect production from yeast extract and peptone through the production of H2 and acetate from fermentation. The microorganisms found in on-electrode communities were mainly affiliated to exoelectrogenic Archaeoglobales and Thermococcales species, whereas in liquid media, the communities were mainly affiliated to fermentative Bacillales and Thermococcales species. The work shows interactions between fermentative microorganisms degrading complex organic matter into fermentation products that are then used by exoelectrogenic microorganisms oxidizing these reduced compounds while respiring on a conductive support. The results confirmed that with carbon cycling, the syntrophic relations between fermentative microorganisms and exoelectrogens could enable some microbes to survive as biofilm in extremely unstable conditions. Graphical Abstract Schematic representation of cross-feeding between fermentative and exoelectrogenic microbes on the surface of the conductive support. B, Bacillus/Geobacillus spp.; Tc, Thermococcales; Gg, Geoglobus spp.; Py, pyruvate; Ac, acetate.}, } @article {pmid31079168, year = {2019}, author = {Edel, M and Horn, H and Gescher, J}, title = {Biofilm systems as tools in biotechnological production.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {13}, pages = {5095-5103}, doi = {10.1007/s00253-019-09869-x}, pmid = {31079168}, issn = {1432-0614}, support = {DFG HO 1910/16-1//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects ; *Bacterial Physiological Phenomena ; Biofilms/drug effects/*growth & development ; Biomass ; Biotechnology/*methods/trends ; Polymers ; }, abstract = {The literature provides more and more examples of research projects that develop novel production processes based on microorganisms organized in the form of biofilms. Biofilms are aggregates of microorganisms that are attached to interfaces. These viscoelastic aggregates of cells are held together and are embedded in a matrix consisting of multiple carbohydrate polymers as well as proteins. Biofilms are characterized by a very high cell density and by a natural retentostat behavior. Both factors can contribute to high productivities and a facilitated separation of the desired end-product from the catalytic biomass. Within the biofilm matrix, stable gradients of substrates and products form, which can lead to a differentiation and adaptation of the microorganisms' physiology to the specific process conditions. Moreover, growth in a biofilm state is often accompanied by a higher resistance and resilience towards toxic or growth inhibiting substances and factors. In this short review, we summarize how biofilms can be studied and what most promising niches for their application can be. Moreover, we highlight future research directions that will accelerate the advent of productive biofilms in biology-based production processes.}, } @article {pmid31078982, year = {2019}, author = {Su, JF and Zhang, YM and Liang, DH and Wang, JX and Wang, Z and Li, M}, title = {Performance and microbial community of an immobilized biofilm reactor (IBR) for Mn(II)-based autotrophic and mixotrophic denitrification.}, journal = {Bioresource technology}, volume = {286}, number = {}, pages = {121407}, doi = {10.1016/j.biortech.2019.121407}, pmid = {31078982}, issn = {1873-2976}, mesh = {Autotrophic Processes ; Biofilms ; Bioreactors ; *Denitrification ; *Microbiota ; Nitrates ; }, abstract = {An immobilized biofilm reactor (IBR) was established to treat nitrate using different electron donors. A novel material, Fe3O4@Cu/PVA, was synthesized as an adsorbent and bacterial immobilized carrier in the reactor. The optimum condition of nitrate removal were pH 7.0, hydraulic retention time (HRT) of 10 h under autotrophic and mixotrophic conditions. Strain H-117 in the mixotrophic reactor had better adaptability to changes in the initial pH. The metabolism in the mixotrophic reactor was more vigorous than that in autotrophic reactor. The microbial communities and structures were evaluated to determine the nitrate removal mechanisms in this system. Microbial analyses demonstrated that different electron donor could influence the bacterial abundance and species in the IBR system. Proteobacteria was the most dominant phylum in all IBRs and accounted for more than 50% of the total phyla. Pseudomonas and Rhizobium were the dominant contributor to the effective removal of nitrate in the IBRs.}, } @article {pmid31078886, year = {2019}, author = {Ahmed, W and Tian, X and Delatolla, R}, title = {Nitrifying moving bed biofilm reactor: Performance at low temperatures and response to cold-shock.}, journal = {Chemosphere}, volume = {229}, number = {}, pages = {295-302}, doi = {10.1016/j.chemosphere.2019.04.176}, pmid = {31078886}, issn = {1879-1298}, mesh = {Biofilms ; *Bioreactors/standards ; *Cold Temperature ; Kinetics ; *Nitrification ; }, abstract = {In contrast with suspended growth systems, attached growth technologies such as the moving bed biofilm reactors (MBBR) have recently demonstrated significant nitrification rates at temperatures as low as 1 °C. The purpose of this study was to investigate the performance of the nitrifying MBBR system at elevated municipal concentrations with exposures to low temperatures and cold-shock conditions down to 1 °C using an enhanced temperature-controlled room. A removal rate of 98.44 ± 4.69 gN·m[-3]·d[-1] was identified as the intrinsic rate of nitrifying MBBR systems at 1 °C and was proposed as the conservative rate for low temperature design. A temperature threshold at which attached growth nitrification displayed a significant decrease in kinetics was identified between 2 °C and 4 °C. Arrhenius correction coefficients of 1.086 and 1.09 previously applied for low temperature nitrifying MBBR systems resulted in conservative modeled removal rates on average 21% lower than the measured rates. Thus, an Arrhenius correction coefficient of 1.049 is proposed between the temperatures of 10 °C and 4 °C and another correction coefficient of 1.149 to model rates at 1 °C. For the transition from 4 °C to 1 °C, the adjustment of a previously reported Theta model is proposed in this study to account for exposure time at low temperatures; with the modified model showing strong correlation with measured rates (R[2] = 0.88). Finally, a comparison of nitrification kinetics between MBBR systems acclimatized to 1 °C and systems that are cold-shocked to 1 °C demonstrated that shocked removal rates are 21% lower.}, } @article {pmid31077449, year = {2019}, author = {Bermejo, P and Sánchez, MC and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz Alonso, M}, title = {Biofilm formation on dental implants with different surface micro-topography: An in vitro study.}, journal = {Clinical oral implants research}, volume = {30}, number = {8}, pages = {725-734}, doi = {10.1111/clr.13455}, pmid = {31077449}, issn = {1600-0501}, mesh = {Aggregatibacter actinomycetemcomitans ; Biofilms ; *Dental Implants ; Fusobacterium nucleatum ; Humans ; Streptococcus oralis ; Titanium ; }, abstract = {OBJECTIVES: To compare biofilm formation on whole dental titanium implants with different surface micro-topography.

METHODS: A multispecies in vitro biofilm model consisting of initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) was grown for 96 hr on sterile titanium dental implants with either minimal (Sa : 0.5-1.0 mm) or moderate-roughness titanium surfaces (Sa : 1.1-2.0 mm). The resulting biofilms were studied with Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscope. Concentrations (colony-forming units per mL [CFU/ml]) of each bacterium were measured by quantitative Polymerase Chain Reaction (qPCR) and compared by Student t tests.

RESULTS: A biofilm, located mainly at the peak and lateral areas of the implant threads, was observed on both implant surfaces, with a greater biomass and a greater live/dead ratio in moderate- compared to minimal-roughness surface implants. Statistically significant higher values of total bacteria (mean difference = 2.61 × 10[7]  CFU/ml; 95% confidence interval - CI [1.91 × 10[6] ; 5.02 × 10[7] ]; p = 0.036), F. Nucleatum (mean difference = 4.43 × 10[6]  CFU/ml; 95% CI [1.06 × 10[6] ; 7.80 × 10[6] ]; p = 0.013) and A. actinomycetemcomitans (mean difference = 2.55 × 10[7]  CFU/ml; 95% CI [1.07 × 10[7] ; 4.04 × 10[7] ]; p = 0.002), were found in the moderate- compared to minimal-roughness surface dental implants.

CONCLUSIONS: Implants with moderate-roughness surfaces accumulated more bacterial biomass and significant higher number of pathogenic bacteria (F. nucleatum and A. actinomycetemcomitans), when compared to implants with minimal-roughness surfaces, within a similar biofilm structure.}, } @article {pmid31077423, year = {2019}, author = {Alves, AR and Sequeira, AM and Cunha, Â}, title = {Increase in bacterial biosurfactant production by co-cultivation with biofilm-forming bacteria.}, journal = {Letters in applied microbiology}, volume = {69}, number = {1}, pages = {79-86}, doi = {10.1111/lam.13169}, pmid = {31077423}, issn = {1472-765X}, support = {UID/AMB/50017 - POCI-01-0145-FEDER-007638//CESAM/ ; //FEDER/ ; }, mesh = {Agar/metabolism ; Bacillus licheniformis/*metabolism ; Biofilms/*growth & development ; Coculture Techniques ; Listeria/*metabolism ; Pseudomonas aeruginosa/*metabolism ; Quorum Sensing ; Surface-Active Agents/*metabolism ; }, abstract = {Considering that bacterial biosurfactants (BSFs) are released as secondary metabolites involved in biotic relations within mixed bacterial assemblages, the hypothesis that the co-cultivation of BSF producing bacteria with biofilm-forming strains would enhance BSF synthesis was tested. Environmental BSF producing strains of Bacillus licheniformis and Pseudomonas sp. were cultivated with reference biofilm-forming strains (Pseudomonas aeruginosa and Listeria innocua). BSF production and quorum-quenching effects were tested in solid media. Tensioactive and anionic BSFs were also quantified in cell-free extracts (CFEs). BSF production increased in co-cultures with inducer strains although this was not demonstrated by all screening methods. Increased concentrations of anionic BSF were detected in CFEs of co-cultures in which Pseudomonas aeruginosa was included as inducer, which is in accordance with the observation of larger halos in cetyl trimethylammonium bromide-methylene blue agar. The results demonstrate that co-cultivation positively affects the efficiency of BSF production and that higher production yields may be attained by selecting convenient inducer partners in designed consortia. SIGNIFICANCE AND IMPACT OF THE STUDY: The high production cost of biosurfactants (BSFs) still represents a major limitation to the industrial use of these otherwise advantageous alternatives to chemical surfactants. This work demonstrates that the co-cultivation of consortia of biosurfactant-producer and biofilm-forming bacteria enhances BSF production and may contribute to the cost-effectiveness of biosurfactant-based products.}, } @article {pmid31077283, year = {2019}, author = {Zeng, Z and Zhan, W and Wang, W and Wang, P and Tang, K and Wang, X}, title = {Biofilm formation in Pseudoalteromonas lipolytica is related to IS5-like insertions in the capsular polysaccharide operon.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {6}, pages = {}, doi = {10.1093/femsec/fiz065}, pmid = {31077283}, issn = {1574-6941}, mesh = {*Biofilms ; *DNA Transposable Elements ; *DNA, Bacterial ; Operon ; Polysaccharides, Bacterial/genetics/*metabolism ; Pseudoalteromonas/genetics/*growth & development/metabolism ; }, abstract = {Bacterial capsular polysaccharides (CPSs) participate in environmental adaptation in diverse bacteria species. However, the role and regulation of CPS production in marine bacteria have remained largely unexplored. We previously reported that both wrinkled and translucent Pseudoalteromonas lipolytica variants with altered polysaccharide production were generated in pellicle biofilm-associated cells. In this study, we observed that translucent variants were generated at a rate of ∼20% in colony biofilms of P. lipolytica cultured on HSLB agar plates for 12 days. The DNA sequencing results revealed that nearly 90% of these variants had an IS5-like element inserted within the coding or promoter regions of nine genes in the cps operon. In contrast, IS5 insertion into the cps operon was not detected in planktonic cells. Furthermore, we demonstrated that the IS5 insertion event inactivated CPS production, which leads to a translucent colony morphology. The CPS-deficient variants showed an increased ability to form attached biofilms but exhibited reduced resistance to sublethal concentrations of antibiotics. Moreover, deleting the DNA repair gene recA significantly decreased the frequency of occurrence of CPS-deficient variants during biofilm formation. Thus, IS insertion into the cps operon is an important mechanism for the production of genetic variants during biofilm formation of marine bacteria.}, } @article {pmid31076293, year = {2019}, author = {Peng, C and Gao, Y and Fan, X and Peng, P and Huang, H and Zhang, X and Ren, H}, title = {Enhanced biofilm formation and denitrification in biofilters for advanced nitrogen removal by rhamnolipid addition.}, journal = {Bioresource technology}, volume = {287}, number = {}, pages = {121387}, doi = {10.1016/j.biortech.2019.121387}, pmid = {31076293}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Glycolipids ; *Nitrogen ; Wastewater ; }, abstract = {Denitrification biofilters (DNBFs) are widely used in advanced nitrogen removal of wastewater with low C/N and effective biofilm formation is critical to their long-term operation. Hereby the influence of rhamnolipid addition in DNBFs was investigated for the first time. Gradient concentrations (0, 20, 40, 80, 120 mg/L) of rhamnolipid were applied to investigate nitrogen removal, biofilm properties and microbial community of lab-scale DNBFs. A significant increase of nitrogen removal was observed in rhamnolipid-treated DNBFs (p < 0.05). Total solid (TS), extracellular polymeric substances (EPS) and adhesion force of biofilms in DNBF with 120 mg/L rhamnolipid reached the maximum, which were 2.17, 2.15 and 3.36 times of those in the control, respectively. Moreover, rhamnolipid exhibited an improvement in abundance of Simplicispira and Gemmatimonas which were responsible for enhanced biofilm formation and denitrification. The results suggested that rhamnolipid addition can be a novel strategy to improve the start-up and denitrification performance of DNBFs.}, } @article {pmid31075206, year = {2019}, author = {Gou, Y and Liu, W and Wang, JJ and Tan, L and Hong, B and Guo, L and Liu, H and Pan, Y and Zhao, Y}, title = {CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli.}, journal = {Canadian journal of microbiology}, volume = {65}, number = {9}, pages = {691-702}, doi = {10.1139/cjm-2019-0100}, pmid = {31075206}, issn = {1480-3275}, mesh = {Biofilms/*growth & development ; CRISPR-Cas Systems ; Escherichia coli/cytology/*genetics/metabolism/physiology ; Escherichia coli Proteins/genetics/*metabolism ; Fimbriae, Bacterial/genetics ; Gene Expression Regulation, Bacterial/*genetics ; Microscopy, Electron, Scanning ; Sequence Deletion ; Virulence ; }, abstract = {Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.}, } @article {pmid31072243, year = {2020}, author = {Spennati, F and Ricotti, A and Mori, G and Siracusa, G and Becarelli, S and Gregorio, SD and Tigini, V and Varese, GC and Munz, G}, title = {The role of cosubstrate and mixing on fungal biofilm efficiency in the removal of tannins.}, journal = {Environmental technology}, volume = {41}, number = {26}, pages = {3515-3523}, doi = {10.1080/09593330.2019.1615128}, pmid = {31072243}, issn = {1479-487X}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Fungi ; *Tannins ; *Wastewater ; }, abstract = {Tannins are polyphenolic compounds produced by plants and they are used in industrial vegetable tanning of leather. Tannins represent one of the low biodegradability substances in tannery wastewaters with high recalcitrant soluble chemical oxygen demand, furthermore high concentration of tannins can inhibit biological treatment. In the present study, four novel rotating submerged packed bed reactors were inoculated with a selected fungal strain to reach a biological degradation of tannins in non-sterile conditions. The selected fungal strain, Aspergillus tubingensis MUT 990, was immobilised in polyurethane foam cubes carriers and inserted inside a submerged rotating cage reactors. The reactors were feed with a solution composed of four tannins: Quebracho (Schinopsis spp.), Wattle (Mimosa spp.), Chestnut (Castanea spp.) and Tara (Caesalpinia spp.). Four reactors with a volume of 4 L each were used, the co-substrate was pure malt extract, the hydraulic retention time was 24 h and the pH setpoint was 5.5. The reactors configuration was chosen to allow the study of the effect of rotation and the co-substrate addition on tannins removal. The experiment lasted two months and it was achieved 80% of chemical oxygen demand and up to 90% dissolved organic carbon removal, furthermore it was detected an important tannase activity.}, } @article {pmid31071421, year = {2019}, author = {Mehta, M and Allen-Gipson, D and Mohapatra, S and Kindy, M and Limayem, A}, title = {Study on the therapeutic index and synergistic effect of Chitosan-zinc oxide nanomicellar composites for drug-resistant bacterial biofilm inhibition.}, journal = {International journal of pharmaceutics}, volume = {565}, number = {}, pages = {472-480}, doi = {10.1016/j.ijpharm.2019.05.003}, pmid = {31071421}, issn = {1873-3476}, mesh = {Animals ; Biofilms/drug effects ; Cell Survival/drug effects ; Chitosan/*administration & dosage/toxicity ; Drug Resistance, Bacterial ; Enterococcus faecalis/*drug effects/physiology ; Epithelial Cells/drug effects ; Intestine, Small/cytology ; *Micelles ; Nanoparticles/*administration & dosage/toxicity ; Rats ; Zinc Oxide/*administration & dosage/toxicity ; }, abstract = {The synergistic effectiveness of chitosan with zinc oxide nanomicelles (CZNPs) on broad spectrum of multidrug resistance (MDR) was previously evidenced in our labs, requiring elucidation of the therapeutic index (TI) for safe in vivo use. This in vitro assessment estimated the effective dose (ED50) of micellar CZNPs for eradication of the MDR Enterococcus faecium 1449 model and the corresponding cytotoxic dose (LD50) against rat small intestinal epithelial cells as functions of TI. In order to visually determine the mechanistic effects of micellar CZNPs on bacterial biofilm size reduction, LIVE/DEAD viability assay was used in conjunction with advanced fluorescence imaging and 3D confocal microscopy. Biofilm quantification was performed through the measure of the fluorescence intensity, using the Biotek Synergy Neo2 for calculating the ED50. To generate the LD50, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay was implemented. Quantification results revealed, at the same concentration (200 µg/mL), micellar CZNPs had average biofilm reduction of approximately 50.22% at 24 h (ED50 = 199.13 µg/mL, LD50 = 240.20 µg/mL, TI = 1.2062), compared to chitosan (15.66%) and ZnO (13.94%) alone. Conclusively, the ED50 of micellar CZNPs on MDR bacterial biofilms (199.13 µg/mL) as a function of TI reveals a promising nanotherapeutic agent in comparison to either Chitosan or ZnO alone.}, } @article {pmid31070474, year = {2019}, author = {Guo, D and Yang, Z and Zheng, X and Kang, S and Yang, Z and Xu, Y and Shi, C and Tian, H and Xia, X}, title = {Thymoquinone Inhibits Biofilm Formation and Attachment-Invasion in Host Cells of Vibrio parahaemolyticus.}, journal = {Foodborne pathogens and disease}, volume = {16}, number = {10}, pages = {671-678}, doi = {10.1089/fpd.2018.2591}, pmid = {31070474}, issn = {1556-7125}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Benzoquinones/*pharmacology ; Biofilms/*growth & development ; Caco-2 Cells ; Humans ; Microbial Sensitivity Tests ; *Quorum Sensing ; Seafood/microbiology ; Vibrio parahaemolyticus/*drug effects/*genetics/pathogenicity ; Virulence/genetics ; Virulence Factors/*genetics ; }, abstract = {Vibrio parahaemolyticus is a halophilic Gram-negative foodborne pathogen that is widely distributed in marine environments. It can cause acute gastroenteritis and other diseases. This study aimed to investigate the antivirulence activity of thymoquinone (TQ) on V. parahaemolyticus. TQ was shown to effectively inhibit V. parahaemolyticus. Subminimum inhibitory concentrations of TQ inhibited swimming and swarming motility, quorum sensing, biofilm formation, the ability of V. parahaemolyticus to adhere and invade the host cells, and the expression of virulence-associated genes of V. parahaemolyticus. These findings suggest that TQ can effectively inhibit the growth of V. parahaemolyticus and significantly reduce its pathogenicity. Considering its safety and various biological activities, TQ has the potential to be developed as a natural antibacterial substance to reduce the diseases associated with V. parahaemolyticus.}, } @article {pmid31067024, year = {2019}, author = {Zhou, R and Zhou, R and Wang, P and Luan, B and Zhang, X and Fang, Z and Xian, Y and Lu, X and Ostrikov, KK and Bazaka, K}, title = {Microplasma Bubbles: Reactive Vehicles for Biofilm Dispersal.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {23}, pages = {20660-20669}, doi = {10.1021/acsami.9b03961}, pmid = {31067024}, issn = {1944-8252}, mesh = {*Biofilms ; Nanotechnology ; Reactive Oxygen Species/chemistry ; Water/chemistry ; }, abstract = {Interactions between effects generated by cold atmospheric-pressure plasmas and water have been widely investigated for water purification, chemical and nanomaterial synthesis, and, more recently, medicine and biotechnology. Reactive oxygen and nitrogen species (RONS) play critical roles in transferring the reactivity from gas plasmas to solutions to induce specific biochemical responses in living targets, e.g., pathogen inactivation and biofilm removal. While this approach works well in a single-organism system at a laboratory scale, integration of plasma-enabled biofilm removal into complex real-life systems, e.g., large aquaculture tanks, is far from trivial. This is because it is difficult to deliver sufficient concentrations of the right kind of species to biofilm-covered surfaces while carefully maintaining a suitable physiochemical environment that is healthy for its inhabitants, e.g., fish. In this work, we show that underwater microplasma bubbles (generated by a microplasma-bubble reactor that forms a dielectric barrier discharge at the gas-liquid interface with the applied voltage of 4.0 kV) act as transport vehicles to efficiently deliver reactive plasma species to the target biofilm sites on artificial and living surfaces while keeping healthy water conditions in a multispecies system. The as-generated air microplasma bubbles and plasma-activated water (PAW) both can effectively reduce the existing pathogenic biofilm load by ∼83 and 60%, respectively, after 15 min of discharge at 40 W and prevent any new biofilm from forming. The generation of underwater microplasma bubbles in a custom-made fish tank for less than a minute per day (20 s per time, twice daily) can introduce sufficient quantities of RONS into PAW to reduce the biofilm-infected area by ∼80-90% and improve the health status of Cichlasoma synspilum × Cichlasoma citrinellum blood parrot cichlid fish. Species generated include hydrogen peroxide, ozone, nitrite, nitrate, and nitric oxide. Using mimicked chemical solutions, we show that the plasma-induced nitric oxide acts as a critical bioactive species that triggers the release of cells from the biofilm and their inactivation.}, } @article {pmid31066733, year = {2019}, author = {Zhang, C and Du, C and Liao, JY and Gu, Y and Gong, Y and Pei, J and Gu, H and Yin, D and Gao, L and Pan, Y}, title = {Synthesis of magnetite hybrid nanocomplexes to eliminate bacteria and enhance biofilm disruption.}, journal = {Biomaterials science}, volume = {7}, number = {7}, pages = {2833-2840}, doi = {10.1039/c9bm00057g}, pmid = {31066733}, issn = {2047-4849}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Chemistry Techniques, Synthetic ; Dose-Response Relationship, Drug ; Escherichia coli/*drug effects/*physiology ; Ferric Compounds/chemistry ; Ferrosoferric Oxide/*chemical synthesis/chemistry/*pharmacology ; Materials Testing ; Metal Nanoparticles/chemistry ; Mice ; NIH 3T3 Cells ; Nanotechnology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Silver/chemistry ; }, abstract = {Bacteria can increase drug resistance by forming bacterial biofilms. Once the biofilm is formed, it becomes difficult to remove or kill the related bacteria completely by antibiotics and other antibacterial agents because these antibacterial agents cannot easily break through the biofilm matrix barrier and reach the internal bacteria. Therefore, we synthesized magnetite hybrid nanocomplexes that can penetrate and disrupt bacterial biofilms. The obtained nanocomposites are composed of multinucleated iron oxides and Ag seeds. The outer iron oxides can help the internal Ag nanoparticles penetrate the bacterial biofilms, hence killing the internal bacteria and disrupting the biofilms. We took advantage of E. coli and P. aeruginosa bacteria to test the antibacterial properties of the magnetite hybrid nanocomplexes. When planktonic E. coli and P. aeruginosa bacteria were incubated with 100 μg mL-1 magnetite hybrid nanocomplexes for 30 min, almost all the bacteria were killed. When the obtained biofilms of E. coli and P. aeruginosa were treated with magnetite hybrid nanocomplexes (10 μg mL-1 and 100 μg mL-1), the survival of E. coli and P. aeruginosa biofilms with a magnetic field showed a big decrease compared with that without a magnetic field. Therefore, the as-synthesized nanocomposites have promising potential as antimicrobial agents for killing bacteria and disrupting biofilms in the presence of a magnetic field, and thus should be further studied for a wide range of antibacterial applications.}, } @article {pmid31064142, year = {2019}, author = {Wei, C and Ding, T and Chang, C and Yu, C and Li, X and Liu, Q}, title = {Global Regulator PhoP is Necessary for Motility, Biofilm Formation, Exoenzyme Production and Virulence of Xanthomonas citri Subsp. citri on Citrus Plants.}, journal = {Genes}, volume = {10}, number = {5}, pages = {}, pmid = {31064142}, issn = {2073-4425}, mesh = {Bacterial Proteins/*genetics ; Biofilms/growth & development ; Citrus/*microbiology ; Gene Expression Regulation, Bacterial/genetics ; Plant Diseases/*genetics/microbiology ; Plant Leaves/genetics/microbiology ; Virulence/genetics ; Xanthomonas/*genetics/pathogenicity ; }, abstract = {Citrus canker caused by Xanthomonas citri subsp. citri is one of the most important bacterial diseases of citrus, impacting both plant growth and fruit quality. Identifying and elucidating the roles of genes associated with pathogenesis has aided our understanding of the molecular basis of citrus-bacteria interactions. However, the complex virulence mechanisms of X. citri subsp. citri are still not well understood. In this study, we characterized the role of PhoP in X. citri subsp. citri using a phoP deletion mutant, ΔphoP. Compared with wild-type strain XHG3, ΔphoP showed reduced motility, biofilm formation, as well as decreased production of cellulase, amylase, and polygalacturonase. In addition, the virulence of ΔphoP on citrus leaves was significantly decreased. To further understand the virulence mechanisms of X. citri subsp. citri, high-throughput RNA sequencing technology (RNA-Seq) was used to compare the transcriptomes of the wild-type and mutant strains. Analysis revealed 1017 differentially-expressed genes (DEGs), of which 614 were up-regulated and 403 were down-regulated in ΔphoP. Gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that the DEGs were enriched in flagellar assembly, two-component systems, histidine metabolism, bacterial chemotaxis, ABC transporters, and bacterial secretion systems. Our results showed that PhoP activates the expression of a large set of virulence genes, including 22 type III secretion system genes and 15 type III secretion system effector genes, as well as several genes involved in chemotaxis, and flagellar and histidine biosynthesis. Two-step reverse-transcription polymerase chain reaction analysis targeting 17 genes was used to validate the RNA-seq data, and confirmed that the expression of all 17 genes, except for that of virB1, decreased significantly. Our results suggest that PhoP interacts with a global signaling network to co-ordinate the expression of multiple virulence factors involved in modification and adaption to the host environment during infection.}, } @article {pmid31063858, year = {2019}, author = {Misba, L and Abdulrahman, H and Khan, AU}, title = {Photodynamic efficacy of toluidine blue O against mono species and dual species bacterial biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {383-388}, doi = {10.1016/j.pdpdt.2019.05.001}, pmid = {31063858}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Dental Caries/microbiology ; Enterococcus faecalis/*drug effects/metabolism ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Reactive Oxygen Species/metabolism ; Singlet Oxygen/metabolism ; Streptococcus mutans/*drug effects/metabolism ; Tolonium Chloride/*pharmacology ; }, abstract = {AIM: The purpose of this study was to investigate how Enterococcus faecalis and Streptococcus mutans behave in mono and dual species biofilm after photodynamic treatment.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) leads to the generation of reactive oxygen species (ROS) that destroys bacterial cells in presence of a photosensitizer, visible light, and oxygen.

MATERIAL AND METHODS: We have taken Enterococcus faecalis and Streptococcus mutans as monospecies culture and their dualspecies culture biofilm. Antibacterial effect was evaluated by colony forming unit while antibiofilm action by crystal violet and congored binding assays.

RESULTS: We found that dual species biofilm are more resistant than monospecies biofilm and S. mutans shows dominance over E. faecalis in dual species biofilm, it inhibited the growth of E. faecalis in dual species biofilm. Antibiofilm efficacy of TBO also validated that dualspecies show less inhibition than monospecies biofilm this may be due to different EPS constitution in dualspecies biofilm, hence less inhibition was observed in EPS production of dualspecies biofilm than monospecies biofilm. Reactive oxygen species and singlet oxygen yield was found to be light dose dependent and antimicrobial photodynamic efficiency is directly related to the ROS production.

CONCLUSION: We conclude that dual species biofilm shows resistance over monospecies biofilm and S. mutans in dual species inhibits the growth of E. faecalis.}, } @article {pmid31062019, year = {2019}, author = {González, MJ and Da Cunda, P and Notejane, M and Zunino, P and Scavone, P and Robino, L}, title = {Fosfomycin tromethamine activity on biofilm and intracellular bacterial communities produced by uropathogenic Escherichia coli isolated from patients with urinary tract infection.}, journal = {Pathogens and disease}, volume = {77}, number = {3}, pages = {}, doi = {10.1093/femspd/ftz022}, pmid = {31062019}, issn = {2049-632X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cells, Cultured ; Child ; Child, Preschool ; Epithelial Cells/*microbiology ; Escherichia coli Infections/microbiology ; Fosfomycin/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Urinary Tract Infections/microbiology ; Uropathogenic Escherichia coli/*drug effects/growth & development/isolation & purification ; }, abstract = {Fosfomycin tromethamine (FT), an old antibiotic revived as a new strategy to overcome antibiotic resistance, is an excellent option for the treatment of lower urinary tract infection (UTI). During UTI, Escherichia coli produces biofilms and could invade the bladder epithelial cells, developing intracellular bacterial communities (IBC). The present work aimed to evaluate the activity of FT on biofilms and IBC from clinical isolates of E. coli. A total of 38 E. coli clinical UTI isolates previously characterized as biofilm and IBC producers were studied. FT susceptibility was evaluated and its activity on 48 h biofilm was determined by microtiter plate-based biofilm assay comparing three different antibiotic concentrations. Two UPEC strains were selected to evaluate FT activity on IBC in vitro using T24 bladder cells. The survival percentage of intracellular bacteria after 24 h exposure to FT was calculated and compared to the percentage of intracellular bacteria without antibiotic. All the strains were susceptible to FT. FT produced a significant reduction of biofilms at the three concentrations tested, compared to the control. However, no statistically effect on IBC was observed after 24 h of fosfomycin exposure in cell culture. FT is a good option for bacterial biofilm reduction within UTI. However, it does not affect IBC.}, } @article {pmid31061169, year = {2019}, author = {Gu, H and Lee, SW and Carnicelli, J and Jiang, Z and Ren, D}, title = {Antibiotic Susceptibility of Escherichia coli Cells during Early-Stage Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31061169}, issn = {1098-5530}, support = {R21 AI142424/AI/NIAID NIH HHS/United States ; S10 OD023617/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Escherichia coli/*drug effects/*physiology ; Microbial Sensitivity Tests ; }, abstract = {Bacteria form complex multicellular structures on solid surfaces known as biofilms, which allow them to survive in harsh environments. A hallmark characteristic of mature biofilms is the high-level antibiotic tolerance (up to 1,000 times) compared with that of planktonic cells. Here, we report our new findings that biofilm cells are not always more tolerant to antibiotics than planktonic cells in the same culture. Specifically, Escherichia coli RP437 exhibited a dynamic change in antibiotic susceptibility during its early-stage biofilm formation. This phenomenon was not strain specific. Upon initial attachment, surface-associated cells became more sensitive to antibiotics than planktonic cells. By controlling the cell adhesion and cluster size using patterned E. coli biofilms, cells involved in the interaction between cell clusters during microcolony formation were found to be more susceptible to ampicillin than cells within clusters, suggesting a role of cell-cell interactions in biofilm-associated antibiotic tolerance. After this stage, biofilm cells became less susceptible to ampicillin and ofloxacin than planktonic cells. However, when the cells were detached by sonication, both antibiotics were more effective in killing the detached biofilm cells than the planktonic cells. Collectively, these results indicate that biofilm formation involves active cellular activities in adaption to the attached life form and interactions between cell clusters to build the complex structure of a biofilm, which can render these cells more susceptible to antibiotics. These findings shed new light on bacterial antibiotic susceptibility during biofilm formation and can guide the design of better antifouling surfaces, e.g., those with micron-scale topographic structures to interrupt cell-cell interactions.IMPORTANCE Mature biofilms are known for their high-level tolerance to antibiotics; however, antibiotic susceptibility of sessile cells during early-stage biofilm formation is not well understood. In this study, we aim to fill this knowledge gap by following bacterial antibiotic susceptibility during early-stage biofilm formation. We found that the attached cells have a dynamic change in antibiotic susceptibility, and during certain phases, they can be more sensitive to antibiotics than planktonic counterparts in the same culture. Using surface chemistry-controlled patterned biofilm formation, cell-surface and cell-cell interactions were found to affect the antibiotic susceptibility of attached cells. Collectively, these findings provide new insights into biofilm physiology and reveal how adaptation to the attached life form may influence antibiotic susceptibility of bacterial cells.}, } @article {pmid31059933, year = {2019}, author = {Johansen, MP and Cresswell, T and Davis, J and Howard, DL and Howell, NR and Prentice, E}, title = {Biofilm-enhanced adsorption of strong and weak cations onto different microplastic sample types: Use of spectroscopy, microscopy and radiotracer methods.}, journal = {Water research}, volume = {158}, number = {}, pages = {392-400}, doi = {10.1016/j.watres.2019.04.029}, pmid = {31059933}, issn = {1879-2448}, mesh = {Adsorption ; Biofilms ; Cations ; Environmental Monitoring ; Microscopy ; *Plastics ; *Water Pollutants, Chemical ; }, abstract = {The adsorption of metals and other elements onto environmental plastics has been previously quantified and is known to be enhanced by surface-weathering and development of biofilms. However, further biofilm-adsorption characterisation is needed with respect to the fate of radionuclides. This study uses spectroscopy, microscopy and radiotracer methods to investigate the adsorption capacity of relatively strong and weak cations onto different microplastic sample types that were conditioned in freshwater, estuarine and marine conditions although marine data were limited. Fourier-transform infrared spectroscopy confirmed that surface oxidation chemistry changes induced by gamma irradiation were similar to those resulting from environmental exposures. Microscopy elemental mapping revealed patchy biofilm development, which contained Si, Al, and O, consistent with microbial-facilitated capture of clays. The plastics+biofilm of all sample types had measurable adsorption for Cs and Sr radiotracers, suggesting environmental plastics act broadly as a sink for the key pervasive environmental radionuclides of [137]Cs and [90]Sr associated with releases from nuclear activities. Adsorption onto high-density polyethylene plastic types was greater than that on polypropylene. However, in most cases, the adsorption rates of all types of plastic+biofilm were much lower than those of reference sediments and roughly consistent with their relative exchangeable surface areas.}, } @article {pmid31058104, year = {2019}, author = {Xie, Z and Meng, K and Yang, X and Liu, J and Yu, J and Zheng, C and Cao, W and Liu, H}, title = {Identification of a Quorum Sensing System Regulating Capsule Polysaccharide Production and Biofilm Formation in Streptococcus zooepidemicus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {121}, pmid = {31058104}, issn = {2235-2988}, mesh = {Bacterial Capsules/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Pheromones/*metabolism ; *Quorum Sensing ; Signal Transduction ; Streptococcus equi/genetics/*growth & development/*metabolism ; Transcription, Genetic ; }, abstract = {Streptococcus zooepidemicus is an important opportunistic pathogen of several species including humans. This organism is also well-known as the main producing strain in industrial production of hyaluronic acid (HA), which is the component of its capsule polysaccharide. How its virulence and capsule polysaccharide production is regulated remains poorly understood. Intercellular chemical signaling among bacteria provides communities of microbes the opportunity to coordinate gene expression to facilitate group behavior, such as pathogenicity, capsule polysaccharide production, etc. Yet no conserved cell-to-cell signaling system has been elucidated in S. zooepidemicus. Encoded within the genome of S. zooepidemicus is one Rgg regulator encoding gene (rgg) with low similarity to both rgg2 and rgg3 from Streptococcus pyogenes. A small ORF (named as shp) encoding a novel short hydrophobic peptide (SHP) was found in the vicinity of rgg. We found that the active form of pheromone is short and hydrophobic (LLLLKLA), corresponding to the C terminal 7 amino acids of the pre-peptide Shp, which shows divergent sequence to all peptide pheromones reported in streptococci. In response to active SHP, Rgg functions as a transcriptional activator to induce the expression of shp, forming a positive feedback circuit. Bacteria social behaviors, such as capsule polysaccharide production and biofilm formation, were significantly affected when the rgg-shp pathway was inactivated. These data provide the first demonstration that Rgg/Shp signaling pathway comprises an active quorum sensing system in S. zooepidemicus.}, } @article {pmid31057729, year = {2019}, author = {Post, SJ and Shapiro, JA and Wuest, WM}, title = {Connecting iron acquisition and biofilm formation in the ESKAPE pathogens as a strategy for combatting antibiotic resistance.}, journal = {MedChemComm}, volume = {10}, number = {4}, pages = {505-512}, pmid = {31057729}, issn = {2040-2511}, support = {R35 GM119426/GM/NIGMS NIH HHS/United States ; }, abstract = {The rise of antibiotic resistant bacteria has become a problem of global concern. Of particular interest are the ESKAPE pathogens, species with high rates of multi-drug resistant infections. Novel antibiotic mechanisms of action are necessary to compliment traditional therapeutics. Recent research has focused on targeting virulence factors as a method of combatting infection without creating selective pressure for resistance or damaging the host commensal microbiome. Some investigations into one such virulence behavior, iron acquisition, have displayed additional effects on another virulence behavior, biofilm formation. The use of exogenous iron-chelators, gallium as an iron mimic, and inhibition of siderophore-mediated iron acquisition are all strategies for disturbing iron-homeostasis that have implicated effects on biofilms. However, the exact nature of this connection remains ambiguous. Herein we summarize these findings and identify opportunities for further investigation.}, } @article {pmid31057497, year = {2019}, author = {Igbinosa, EO and Beshiru, A}, title = {Antimicrobial Resistance, Virulence Determinants, and Biofilm Formation of Enterococcus Species From Ready-to-Eat Seafood.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {728}, pmid = {31057497}, issn = {1664-302X}, abstract = {Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp (n = 288), boiled shrimp (n = 216), and smoked shrimp (n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby-Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis, 17 (28.8%); E. faecium, 29 (49.2%); E. gallinarum, 6 (10.2%); E. casseliflavus, 2 (3.4%); E. hirae, 3 (5.1%); and E. durans, 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3-11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: ermA, 13/29 (44.8%); vanA, 14/22 (63.6%); tetA, 14/27 (51.9%); tetM, 15/27 (55.6%); ermB, 4/29 (13.8%); and vanB, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum, and E. hirae. This study further revealed that RTE food products are reservoirs of potential virulent enterococci with antibiotic-resistant capabilities. This provides useful data for risk assessment and indicates that these foods may present a potential public health risk to consumers.}, } @article {pmid31055910, year = {2019}, author = {Lee, JH and Kim, YG and Khadke, SK and Yamano, A and Watanabe, A and Lee, J}, title = {Inhibition of Biofilm Formation by Candida albicans and Polymicrobial Microorganisms by Nepodin via Hyphal-Growth Suppression.}, journal = {ACS infectious diseases}, volume = {5}, number = {7}, pages = {1177-1187}, doi = {10.1021/acsinfecdis.9b00033}, pmid = {31055910}, issn = {2373-8227}, mesh = {Acinetobacter baumannii/drug effects/physiology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects/*physiology ; Drug Resistance, Fungal/drug effects ; Fluconazole/pharmacology ; Fungal Proteins/genetics ; Gene Expression Regulation, Fungal/drug effects ; Hyphae/drug effects ; Microbial Sensitivity Tests ; Naphthalenes/*pharmacology ; Plant Extracts/chemistry/pharmacology ; Plant Roots/chemistry ; Pseudomonas aeruginosa/drug effects/physiology ; Rumex/*chemistry ; Sequence Analysis, RNA ; Staphylococcus aureus/drug effects/physiology ; Virulence Factors/genetics ; }, abstract = {Candida albicans is an opportunistic pathogenic yeast and is responsible for candidiasis. It readily colonizes host tissues and implant devices, and forms biofilms, which play an important role in pathogenesis and drug resistance. In this study, the antibiofilm, antihyphal, and antivirulence activities of nepodin, isolated from Rumex japonicus roots, were investigated against a fluconazole-resistant C. albicans strain and against polymicrobial-microorganism-biofilm formation. Nepodin effectively inhibited C. albicans biofilm formation without affecting its planktonic cell growth. Also, Rumex-root extract and nepodin both inhibited hyphal growth and cell aggregation of C. albicans. Interestingly, nepodin also showed antibiofilm activities against Candida glabrata, Candida parapsilosis, Staphylococcus aureus, and Acinetobacter baumannii strains and against dual biofilms of C. albicans and S. aureus or A. baumannii but not against Pseudomonas aeruginosa. Transcriptomic analysis performed by RNA-seq and qRT-PCR showed nepodin repressed the expression of several hypha- and biofilm-related genes (ECE1, HGT10, HWP1, and UME6) and increased the expression of several transport genes (CDR4, CDR11, and TPO2), which supported phenotypic changes. Moreover, nepodin reduced C. albicans virulence in a nematode-infection model and exhibited minimal cytotoxicity against the nematode and an animal cell line. These results demonstrate that nepodin and Rumex-root extract might be useful for controlling C. albicans infections and multispecies biofilms.}, } @article {pmid31055471, year = {2019}, author = {Lynch, C and O'Connor, JA and O'Brien, D and Vaughan, C and Bolton, D and Coffey, A and Lucey, B}, title = {First reported detection of biofilm formation by Campylobacter fetus during investigation of a case of prosthetic valve endocarditis.}, journal = {Journal of clinical pathology}, volume = {72}, number = {8}, pages = {554-557}, doi = {10.1136/jclinpath-2018-205677}, pmid = {31055471}, issn = {1472-4146}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Campylobacter Infections/diagnosis/*microbiology/transmission ; Campylobacter fetus/*growth & development/isolation & purification ; Endocarditis, Bacterial/diagnosis/*microbiology/transmission ; Heart Valve Prosthesis/*adverse effects ; Heart Valve Prosthesis Implantation/*adverse effects/*instrumentation ; Humans ; Prosthesis-Related Infections/diagnosis/*microbiology/transmission ; Zoonoses/diagnosis/*microbiology/transmission ; }, abstract = {AIMS: Campylobacter fetus subsp fetus (CFF) can cause intestinal illness, particularly in immunocompromised humans, with the potential to cause severe systemic infections. CFF is a zoonotic pathogen with a broad host range among farm animals and humans, inducing abortion in sheep and cows. The current paper describes a strain of CFF isolated from a patient with prosthetic valve endocarditis in Mercy University Hospital, Cork, Ireland, during 2017. Only five cases of C. fetus as a cause of prosthetic valve endocarditis have been reported in the literature, with no reports of biofilm formation within the species.

METHODS: The aetiological strain was speciated and subspeciated by the VITEK 2 NH card and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. CFF biofilm formation was analysed using a crystal violet staining method. C. jejuni National Collection of Type Cultures (NCTC) 11168 was used as a positive control organism. Strains were incubated statically in Mueller-Hinton broth and Mueller-Hinton broth supplemented with 0.025% sodium deoxycholate for 3 and 7 days at 37°C, microaerobically.

RESULTS: The CFF strain formed stronger attached biofilms on polystyrene plates on day 3 (72 hours) than the C. jejuni NCTC 11168 control strain, but were weaker than the control strain on day 7 in Mueller-Hinton broth. Monoculture of this C. fetus isolate was found to exist in three defined forms of biofilms (attached, air-liquid interface and floccules).

CONCLUSIONS: This clinically significant C. fetus isolate showed considerable biofilm-forming capability, which we suggest conferred a survivalist advantage, contributing to the genesis of infective prosthetic valve endocarditis.}, } @article {pmid31054395, year = {2019}, author = {Peng, L and Ngo, HH and Song, S and Xu, Y and Guo, W and Liu, Y and Wei, W and Chen, X and Wang, D and Ni, BJ}, title = {Heterotrophic denitrifiers growing on soluble microbial products contribute to nitrous oxide production in anammox biofilm: Model evaluation.}, journal = {Journal of environmental management}, volume = {242}, number = {}, pages = {309-314}, doi = {10.1016/j.jenvman.2019.04.084}, pmid = {31054395}, issn = {1095-8630}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Heterotrophic Processes ; *Nitrous Oxide ; Oxidation-Reduction ; }, abstract = {In this work, a model framework was constructed to assess and predict nitrous oxide (N2O) production, substrate and microbe interactions in an anammox biofilm bioreactor. The anammox kinetics were extended by including kinetics of autotrophic soluble microbial products (SMP) formation, which consisted of utilization-associated products (UAP) and biomass-associated products (BAP). Heterotrophic bacteria growing on UAP, BAP and decay released substance (SS) were modelled to perform four-step sequential reductions from nitrate to dinitrogen gas. N2O was modelled as an intermidiate of heterotrophic denitrification via three pathways with UAP, BAP and SS as the electron donors. The developed model framework was evaluated using long-term operational data from an anammox biofilm reactor and satisfactorily reproduced effluent nitrogen and SMP as well as N2O emission factors under different operational conditions. The modeling results revealed that N2O was mainly produced with UAP as the electron donor while BAP and SS play minor roles. Heterotrophic denitrifiers growing on UAP would significantly contribute to N2O emission from anammox biofilm reactor even though heterotrophs only account for a relatively small fraction of active biomass in the anammox biofilm. Comprehensive simulations were conducted to investigate the effects of N loading rate and biofilm thickness, which indicated that maintaining a low N loading rate and a thick biofilm thickness were essential for high total nitrogen removal efficiency and low N2O emission.}, } @article {pmid31054134, year = {2019}, author = {Babbar, A and Barrantes, I and Pieper, DH and Itzek, A}, title = {Superantigen SpeA attenuates the biofilm forming capacity of Streptococcus pyogenes.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {7}, pages = {626-636}, pmid = {31054134}, issn = {1976-3794}, mesh = {*Bacterial Proteins/pharmacology/physiology ; Biofilms/*drug effects ; *Exotoxins/pharmacology/physiology ; Gene Expression Profiling/methods ; Humans ; *Membrane Proteins/pharmacology/physiology ; Streptococcal Infections/*microbiology ; *Streptococcus pyogenes/drug effects/genetics/pathogenicity ; Superantigens/physiology ; }, abstract = {Beta haemolytic Group A streptococcus (GAS) or Streptococcus pyogenes are strict human pathogens responsible for mild to severe fatal invasive infections. Even with enormous number of reports exploring the role of S. pyogenes exotoxins in its pathogenesis, inadequate knowledge on the biofilm process and the potential role of exotoxins in bacterial dissemination from matured biofilms has been a hindrance in development of effective and targeted treatments. Therefore, the present study was aimed in investigating the uncharted role of these exotoxins in biofilm process. Through our study the putative role of ciaRH in the SpeA dependent ablation of biofilm formation could be speculated and thus helping in bacterial dissemination. The seed-dispersal effect of SpeA was time and concentration dependent and seen to be consistent within various streptococcal species. Transcriptome analysis of SpeA treated S. pyogenes biofilms revealed the involvement of many transcriptional regulators (ciaRH) and response genes (luxS, shr, shp, SPy_0572), hinting towards specific mechanisms underlying the dispersal effect by SpeA. This finding opens up a discussion towards understanding a new mechanism involved in the pathogenesis of Streptococcus pyogenes and might help in understanding the bacterial infections in a better way.}, } @article {pmid31054133, year = {2019}, author = {Taha, MN and Saafan, AE and Ahmedy, A and El Gebaly, E and Khairalla, AS}, title = {Two novel synthetic peptides inhibit quorum sensing-dependent biofilm formation and some virulence factors in Pseudomonas aeruginosa PAO1.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {7}, pages = {618-625}, pmid = {31054133}, issn = {1976-3794}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Peptides/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Virulence Factors/*metabolism ; }, abstract = {Quorum sensing (QS) regulates virulence factor expression in Pseudomonas aeruginosa. Inhibiting the QS-controlled virulence factors without inhibiting the growth of P. aeruginosa is a promising approach for overcoming the widespread resistance of P. aeruginosa. This study was proposed to investigate the effects of two novel synthetic peptides on the biofilm development and virulence factor production of P. aeruginosa. The tested strain was P. aeruginosa PAO1. The results indicated that both of the synthetic peptides (LIVRHK and LIVRRK) inhibited (P < 0.05) the formation of biofilms and the production of virulence factors, including pyocyanin, protease, and rhamnolipids, without inhibiting the growth of PAO1. Additionally, we detected transcriptional changes related to QS and found a significant reduction in the levels of gene expression of lasI, lasR, rhlI, and rhlR. This study demonstrates that LIVRRK and LIVRHK are novel synthetic peptides that can act as potent inhibitors of QS-regulated virulence factors in P. aeruginosa. Moreover, these synthetic peptides have potential applications in the treatment of biofilmrelated diseases. Both peptides may be able to control chronic infections and biofilm-associated problems of P. aeruginosa.}, } @article {pmid31053580, year = {2019}, author = {Gu, D and Zhang, J and Hao, Y and Xu, R and Zhang, Y and Ma, Y and Wang, Q}, title = {Alternative Sigma Factor RpoX Is a Part of the RpoE Regulon and Plays Distinct Roles in Stress Responses, Motility, Biofilm Formation, and Hemolytic Activities in the Marine Pathogen Vibrio alginolyticus.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {14}, pages = {}, pmid = {31053580}, issn = {1098-5336}, mesh = {Animals ; Base Sequence ; *Biofilms ; DNA, Bacterial/*genetics/metabolism ; Fish Diseases/*microbiology ; Hemolysis ; Regulon ; Sigma Factor/*genetics/metabolism ; Stress, Physiological ; Vibrio Infections/microbiology/*veterinary ; Vibrio alginolyticus/genetics/*physiology ; *Zebrafish ; }, abstract = {Vibrio alginolyticus is one of the most abundant microorganisms in marine environments and is also an opportunistic pathogen mediating high-mortality vibriosis in marine animals. Alternative sigma factors play essential roles in bacterial pathogens in the adaptation to environmental changes during infection and the adaptation to various niches, but little is known about them for V. alginolyticus Our previous investigation indicated that the transcript level of the gene rpoX significantly decreased in an RpoE mutant. Here, we found that rpoX was highly expressed in response to high temperature and low osmotic stress and was under the direct control of the alternative sigma factor RpoE and its own product RpoX. Moreover, transcriptome sequencing (RNA-seq) results showed that RpoE and RpoX had different regulons, although they coregulated 105 genes at high temperature (42°C), including genes associated with biofilm formation, motility, virulence, regulatory factors, and the stress response. RNA-seq and chromatin immunoprecipitation sequencing (ChIP-seq) analyses as well as electrophoretic mobility shift assays (EMSAs) revealed the distinct binding motifs of RpoE and RpoX proteins. Furthermore, quantitative real-time reverse transcription-PCR (qRT-PCR) analysis also confirmed that RpoX can upregulate genes associated with flagella, biofilm formation, and hemolytic activities at higher temperatures. rpoX abrogation does not appear to attenuate virulence toward model fish at normal temperature. Collectively, data from this study demonstrated the regulatory cascades of RpoE and an alternative sigma factor, RpoX, in response to heat and osmotic stresses and their distinct and overlapping roles in pathogenesis and stress responses in the marine bacterium V. alginolyticusIMPORTANCE The alternative sigma factor RpoE is essential for the virulence of Vibrio alginolyticus toward marine fish, coral, and other animals in response to sea surface temperature increases. In this study, we characterized another alternative sigma factor, RpoX, which is induced at high temperatures and under low-osmotic-stress conditions. The expression of rpoX is under the tight control of RpoE and RpoX. Although RpoE and RpoX coregulate 105 genes, they are programming different regulatory functions in stress responses and virulence in V. alginolyticus These findings illuminated the RpoE-RpoX-centered regulatory cascades and their distinct and overlapping regulatory roles in V. alginolyticus, which facilitates unraveling of the mechanisms by which the bacterium causes diseases in various sea animals in response to temperature fluctuations as well as the development of appropriate strategies to tackle infections by this bacterium.}, } @article {pmid31052271, year = {2019}, author = {Bahamondez-Canas, TF and Heersema, LA and Smyth, HDC}, title = {Current Status of In Vitro Models and Assays for Susceptibility Testing for Wound Biofilm Infections.}, journal = {Biomedicines}, volume = {7}, number = {2}, pages = {}, pmid = {31052271}, issn = {2227-9059}, support = {DGE-1610403//National Science Foundation/ ; }, abstract = {Biofilm infections have gained recognition as an important therapeutic challenge in the last several decades due to their relationship with the chronicity of infectious diseases. Studies of novel therapeutic treatments targeting infections require the development and use of models to mimic the formation and characteristics of biofilms within host tissues. Due to the diversity of reported in vitro models and lack of consensus, this review aims to provide a summary of in vitro models currently used in research. In particular, we review the various reported in vitro models of Pseudomonas aeruginosa biofilms due to its high clinical impact in chronic wounds and in other chronic infections. We assess advances in in vitro models that incorporate relevant multispecies biofilms found in infected wounds, such as P. aeruginosa with Staphylococcus aureus, and additional elements such as mammalian cells, simulating fluids, and tissue explants in an attempt to better represent the physiological conditions found at an infection site. It is hoped this review will aid researchers in the field to make appropriate choices in their proposed studies with regards to in vitro models and methods.}, } @article {pmid31050052, year = {2019}, author = {Guo, J and Qin, S and Wei, Y and Liu, S and Peng, H and Li, Q and Luo, L and Lv, M}, title = {Silver nanoparticles exert concentration-dependent influences on biofilm development and architecture.}, journal = {Cell proliferation}, volume = {52}, number = {4}, pages = {e12616}, pmid = {31050052}, issn = {1365-2184}, support = {//LU JIAXI International team program supported by the K.C. Wong Education Foundation and CAS/ ; QYZDJ-SSW-SLH031//the Key Research Program of Frontier Sciences, CAS/ ; 2016YFA0201200//the National Key R&D Program of China/ ; 2016YFA0400900//the National Key R&D Program of China/ ; U1632125//National Natural Science Foundation of China/ ; 21705159//National Natural Science Foundation of China/ ; 61571278//National Natural Science Foundation of China/ ; 31571014//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Metal Nanoparticles/*administration & dosage ; Microscopy, Electron, Transmission/methods ; Particle Size ; Plant Extracts/pharmacology ; Pseudomonas aeruginosa/*drug effects ; Silver/*pharmacology ; }, abstract = {OBJECTIVES: To investigate the impact of silver nanoparticles (AgNPs) on the biofilm growth and architecture.

MATERIALS AND METHODS: Silver nitrate was reduced by d-maltose to prepare AgNPs in the presence of ammonia and sodium hydroxide. The physicochemical properties of AgNPs were characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and inductively coupled plasma mass spectrometry. The development of biofilm with and without AgNPs was explored by crystal violet stain. The structures of mature biofilm were visually studied by confocal laser scanning microscopy and scanning electron microscopy. Bacterial cell, polysaccharide and protein within biofilm were assessed quantitatively by colony-counting method, phenol-sulphuric acid method and Bradford assay, respectively.

RESULTS: The spherical AgNPs (about 30 nm) were successfully synthesized. The effect of AgNPs on Pseudomonas aeruginosa biofilm development was concentration-dependent. Biofilm was more resistant to AgNPs than planktonic cells. Low doses of AgNPs exposure remarkably delayed the growth cycle of biofilm, whereas high concentration (18 μg/mL) of AgNPs fully prevented biofilm development. The analysis of biofilm architecture at the mature stage demonstrated that AgNPs exposure at all concentration led to significant decrease of cell viability within treated biofilms. However, sublethal doses of AgNPs increased the production of both polysaccharide and protein compared to control, which significantly changed the biofilm structure.

CONCLUSIONS: AgNPs exert concentration-dependent influences on biofilm development and structure, which provides new insight into the role of concentration played in the interaction between antibacterial nanoparticles and biofilm, especially, an ignored sublethal concentration associated with potential unintended consequences.}, } @article {pmid31044250, year = {2019}, author = {Alcaraz, E and García, C and Friedman, L and de Rossi, BP}, title = {The rpf/DSF signalling system of Stenotrophomonas maltophilia positively regulates biofilm formation, production of virulence-associated factors and β-lactamase induction.}, journal = {FEMS microbiology letters}, volume = {366}, number = {6}, pages = {}, doi = {10.1093/femsle/fnz069}, pmid = {31044250}, issn = {1574-6968}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Gram-Negative Bacterial Infections/microbiology ; Humans ; Moths/microbiology ; Siderophores/metabolism ; Stenotrophomonas maltophilia/genetics/growth & development/*metabolism/pathogenicity ; Virulence ; Virulence Factors/*biosynthesis/genetics ; beta-Lactamases/genetics/*metabolism ; }, abstract = {Stenotrophomonas maltophilia is a multidrug-resistant opportunistic pathogen. S. maltophilia quorum-sensing system is mediated by the diffusible signal factor (DSF), which synthesis depends on rpfF. It has been reported that rpfF disruption in S. maltophilia K279a leads to a loss of DSF synthesis, reduced levels of extracellular protease, swarming motility and virulence in the Galleria mellonella model. The aim of this work was to attain a deeper knowledge of the role of the rpf/DSF signalling system in S. maltophilia biofilm formation, phenotypic traits associated with biofilm development and virulence and antimicrobial susceptibility. To this end, comparative studies were conducted on S. maltophilia K279a and K279arpfF. The results presented here put in evidence the positive role of DSF in bacterial growth, biofilm formation, swimming and twitching motilities, DNAse, lipases and siderophores production as well as resistance to oxidative stress. Interestingly, DSF seems to be essential for the development of the spatially organised structure seen in mature biofilms. Therefore, DSF from S. maltophlia K279a positively regulates biofilm formation and virulence. Furthermore, DSF is necessary for the induction of L1 and L2 β-lactamase production in K279a. This is the first evidence of the role of the rpf/DSF signalling system in S. maltophilia β-lactam resistance.}, } @article {pmid31042554, year = {2019}, author = {de Carvalho Leonel, L and Carvalho, ML and da Silva, BM and Zamuner, S and Alberto-Silva, C and Silva Costa, M}, title = {Photodynamic Antimicrobial Chemotherapy (PACT) using methylene blue inhibits the viability of the biofilm produced by Candida albicans.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {316-323}, doi = {10.1016/j.pdpdt.2019.04.026}, pmid = {31042554}, issn = {1873-1597}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Light ; Methylene Blue/*pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; }, abstract = {BACKGROUND: Candida albicans is an opportunistic fungus, an etiological agent of human infections, presenting high rates of morbidity and mortality. The resistance of C. albicans to conventional therapies has been reported due to the extensive use of conventional antifungals. Photodynamic antimicrobial chemotherapy (PACT) is a technique that combines a visible light with a specific wavelength and a photosensitizer, producing ROS and permanent damages in the treated cells.

METHODS: In this work, the effects of PACT, using Methylene Blue (MB), as a photosensitizer, on C. albicans development were studied.

RESULTS: Significant reduction in both cell growth and biofilm formation after PACT were observed, in a dependent manner on both MB concentration and fluence. In the presence of MB 0.02 mg/mL, it was observed inhibition in biofilm formation of ˜58, 70 and 74%, using fluences of 10, 20 and 30 J/cm[2], respectively. Also, it was observed inhibition of 54, 66 and 55% in the presence of MB 0.01, 0.02 and 0.05 mg/mL, respectively in the viability of biofilm produced by C. albicans. The number of both yeast and filaments present in the structure of biofilm were reduced after PACT. Furthermore, PACT changed the growth kinetics of C. albicans. Interestingly, we demonstrated increase in the extent of lag phase and an alteration in the profile of the exponential phase after PACT.

CONCLUSIONS: Taken together, these results indicate the potential PACT effects using MB to decrease the C. albicans development.}, } @article {pmid31040831, year = {2019}, author = {Crenier, C and Sanchez-Thirion, K and Bec, A and Felten, V and Ferriol, J and González, AG and Leflaive, J and Perrière, F and Ten-Hage, L and Danger, M}, title = {Interactive Impacts of Silver and Phosphorus on Autotrophic Biofilm Elemental and Biochemical Quality for a Macroinvertebrate Consumer.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {732}, pmid = {31040831}, issn = {1664-302X}, abstract = {Autotrophic biofilms are complex and fundamental biological compartments of many aquatic ecosystems. In particular, these biofilms represent a major resource for many invertebrate consumers and the first ecological barrier against toxic metals. To date, very few studies have investigated the indirect effects of stressors on upper trophic levels through alterations of the quality of biofilms for their consumers. In a laboratory study, we investigated the single and combined effects of phosphorus (P) availability and silver, a re-emerging contaminant, on the elemental [carbon (C):nitrogen (N):P ratios] and biochemical (fatty acid profiles) compositions of a diatom-dominated biofilm initially collected in a shallow lake. We hypothesized that (1) P and silver, through the replacement of diatoms by more tolerant primary producer species, reduce the biochemical quality of biofilms for their consumers while (2) P enhances biofilm elemental quality and (3) silver contamination of biofilm has negative effects on consumers life history traits. The quality of biofilms for consumers was assessed for a common crustacean species, Gammarus fossarum, by measuring organisms' survival and growth rates during a 42-days feeding experiment. Results mainly showed that species replacement induced by both stressors affected biofilm fatty acid compositions, and that P immobilization permitted to achieve low C:P biofilms, whatever the level of silver contamination. Gammarids growth and survival rates were not significantly impacted by the ingestion of silver-contaminated resource. On the contrary, we found a significant positive relationship between the biofilm P-content and gammarids growth. This study underlines the large indirect consequences stressors could play on the quality of microbial biomass for consumers, and, in turn, on the whole food web.}, } @article {pmid31040399, year = {2019}, author = {Hold, GL and Allen-Vercoe, E}, title = {Gut microbial biofilm composition and organisation holds the key to CRC.}, journal = {Nature reviews. Gastroenterology & hepatology}, volume = {16}, number = {6}, pages = {329-330}, doi = {10.1038/s41575-019-0148-4}, pmid = {31040399}, issn = {1759-5053}, mesh = {Biofilms ; *Colonic Neoplasms ; *Gastrointestinal Microbiome ; Humans ; Intestinal Mucosa ; }, } @article {pmid31040333, year = {2019}, author = {Melo, LDR and Ferreira, R and Costa, AR and Oliveira, H and Azeredo, J}, title = {Efficacy and safety assessment of two enterococci phages in an in vitro biofilm wound model.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6643}, pmid = {31040333}, issn = {2045-2322}, mesh = {3T3 Cells ; Animals ; Bacteriolysis ; Bacteriophages/isolation & purification/*physiology/ultrastructure ; *Biofilms ; Cell Survival ; Enterococcus/*virology ; Epithelial Cells/virology ; Genes, Viral ; Host Specificity ; Humans ; Hydrogen-Ion Concentration ; Mice ; *Phage Therapy ; Temperature ; Wound Infection/*microbiology/*therapy ; }, abstract = {Chronic wounds affect thousands of people worldwide, causing pain and discomfort to patients and represent significant economical burdens to health care systems. The treatment of chronic wounds is very difficult and complex, particularly when wounds are colonized by bacterial biofilms which are highly tolerant to antibiotics. Enterococcus faecium and Enterococcus faecalis are within the most frequent bacteria present in chronic wounds. Bacteriophages (phages) have been proposed as an efficient and alternative against antibiotic-resistant infections, as those found in chronic wounds. We have isolated and characterized two novel enterococci phages, the siphovirus vB_EfaS-Zip (Zip) and the podovirus vB_EfaP-Max (Max) to be applied during wound treatment. Both phages demonstrated lytic behavior against E. faecalis and E. faecium. Genome analysis of both phages suggests the absence of genes associated with lysogeny. A phage cocktail containing both phages was tested against biofilms formed in wound simulated conditions at a multiplicity of infection of 1.0 and a 2.5 log CFU.mL[-1] reduction in the bacterial load after at 3 h of treatment was observed. Phages were also tested in epithelial cells colonized by these bacterial species and a 3 log CFU.mL[-1] reduction was observed using both phages. The high efficacy of these new isolated phages against multi-species biofilms, their stability at different temperatures and pH ranges, short latent periods and non-cytotoxicity to epithelial cells suggest their therapeutic use to control infectious biofilms present in chronic wounds.}, } @article {pmid31038914, year = {2019}, author = {Nagay, BE and Dini, C and Cordeiro, JM and Ricomini-Filho, AP and de Avila, ED and Rangel, EC and da Cruz, NC and Barão, VAR}, title = {Visible-Light-Induced Photocatalytic and Antibacterial Activity of TiO2 Codoped with Nitrogen and Bismuth: New Perspectives to Control Implant-Biofilm-Related Diseases.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {20}, pages = {18186-18202}, doi = {10.1021/acsami.9b03311}, pmid = {31038914}, issn = {1944-8252}, mesh = {Actinomyces/*physiology ; Actinomycosis/*therapy ; *Biofilms/drug effects/growth & development/radiation effects ; *Bismuth/chemistry/pharmacology ; Catalysis ; Cells, Cultured ; Fibroblasts/metabolism/microbiology ; Humans ; *Light ; *Nitrogen/chemistry/pharmacology ; *Photochemical Processes ; Streptococcal Infections/*therapy ; Streptococcus sanguis/*physiology ; *Titanium/chemistry/pharmacology ; }, abstract = {Biofilm-associated diseases are one of the main causes of implant failure. Currently, the development of implant surface treatment goes beyond the osseointegration process and focuses on the creation of surfaces with antimicrobial action and with the possibility to be re-activated (i.e., light source activation). Titanium dioxide (TiO2), an excellent photocatalyst used for photocatalytic antibacterial applications, could be a great alternative, but its efficiency is limited to the ultraviolet (UV) range of the electromagnetic spectrum. Since UV radiation has carcinogenic potential, we created a functional TiO2 coating codoped with nitrogen and bismuth via the plasma electrolytic oxidation (PEO) of titanium to achieve an antibacterial effect under visible light with re-activation potential. A complex surface topography was demonstrated by scanning electron microscopy and three-dimensional confocal laser scanning microscopy. Additionally, PEO-treated surfaces showed greater hydrophilicity and albumin adsorption compared to control, untreated titanium. Bismuth incorporation shifted the band gap of TiO2 to the visible region and facilitated higher degradation of methyl orange (MO) in the dark, with a greater reduction in the concentration of MO after visible-light irradiation even after 72 h of aging. These results were consistent with the in vitro antibacterial effect, where samples with nitrogen and bismuth in their composition showed the greatest bacterial reduction after 24 h of dual-species biofilm formation (Streptococcus sanguinis and Actinomyces naeslundii) in darkness with a superior effect at 30 min of visible-light irradiation. In addition, such a coating presents reusable photocatalytic potential and good biocompatibility by presenting a noncytotoxicity effect on human gingival fibroblast cells. Therefore, nitrogen and bismuth incorporation into TiO2 via PEO can be considered a promising alternative for dental implant application with antibacterial properties in darkness, with a stronger effect after visible-light application.}, } @article {pmid31038103, year = {2019}, author = {El-Khatib, M and Tetreau, G and Colletier, JP}, title = {[Porins: a vital role and a social link within the bacterial biofilm of P. stuartii].}, journal = {Medecine sciences : M/S}, volume = {35}, number = {4}, pages = {291-295}, doi = {10.1051/medsci/2019059}, pmid = {31038103}, issn = {1958-5381}, mesh = {*Biofilms/growth & development ; Humans ; Microbial Viability ; Models, Molecular ; Porins/*physiology ; Protein Multimerization/physiology ; Protein Structure, Quaternary ; Providencia/growth & development/*physiology ; }, } @article {pmid31037765, year = {2019}, author = {Vinod Kumar, K and Lall, C and Raj, RV and Vijayachari, P}, title = {Coaggregation and biofilm formation of Leptospira with Staphylococcus aureus.}, journal = {Microbiology and immunology}, volume = {63}, number = {3-4}, pages = {147-150}, doi = {10.1111/1348-0421.12679}, pmid = {31037765}, issn = {1348-0421}, support = {Intramural Grant//Indian Council of Medical Research/ ; }, mesh = {Biofilms/*growth & development ; Coinfection/microbiology/pathology ; Leptospira interrogans/*growth & development ; Leptospirosis/microbiology/pathology ; Microbial Interactions/*physiology ; Microscopy, Electron, Scanning ; Skin Diseases, Bacterial/*microbiology/pathology ; Staphylococcal Infections/microbiology/pathology ; Staphylococcus aureus/*growth & development ; }, abstract = {It is not known how Leptospira react to wound or a cut infected with microbes, such as pathogenic Staphylococcus, or their common habitat on oral or nasal mucosal membranes. In the present study, Staphylococcus aureus MTCC-737 showed strong co-aggregation with leptospiral strains (>75%, visual score of + 4) in vitro. All tested strains of Leptospira were able to form biofilm with S. aureus. Scanning electron microscopy analysis revealed intertwined networks of attached cells of L. interrogans and S. aureus, thus providing evidence of a matrix-like structure. This phenomenon may have implications in Leptospira infection, which occurs via cuts and wounds of the skin.}, } @article {pmid31036689, year = {2019}, author = {Vargas-Cruz, N and Reitzel, RA and Rosenblatt, J and Chaftari, AM and Wilson Dib, R and Hachem, R and Kontoyiannis, DP and Raad, II}, title = {Nitroglycerin-Citrate-Ethanol Catheter Lock Solution Is Highly Effective for In Vitro Eradication of Candida auris Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {7}, pages = {}, pmid = {31036689}, issn = {1098-6596}, mesh = {Amphotericin B/pharmacology ; Anidulafungin/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms ; Candida/*drug effects ; Caspofungin/pharmacology ; Catheter-Related Infections/prevention & control ; Catheters/*microbiology ; Citric Acid/*pharmacology ; Ethanol/pharmacology ; Fluconazole/pharmacology ; Micafungin/pharmacology ; Nitroglycerin/*pharmacology ; Pharmaceutical Solutions ; Voriconazole/pharmacology ; }, abstract = {Candida auris poses emerging risks for causing severe central line-associated bloodstream infections. We tested in vitro the ability of antifungal lock solutions to rapidly eradicate C. auris biofilms. Liposomal amphotericin B, amphotericin B deoxycholate, fluconazole, voriconazole, micafungin, caspofungin, and anidulafungin failed to completely eradicate all 10 tested C. auris biofilms. Conversely, nitroglycerin-citrate-ethanol (NiCE) catheter lock solution completely eradicated all replicates for all of C. auris biofilms tested.}, } @article {pmid31035915, year = {2019}, author = {Perera, M and Wijayarathna, D and Wijesundera, S and Chinthaka, M and Seneviratne, G and Jayasena, S}, title = {Biofilm mediated synergistic degradation of hexadecane by a naturally formed community comprising Aspergillus flavus complex and Bacillus cereus group.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {84}, pmid = {31035915}, issn = {1471-2180}, mesh = {Alkanes/*metabolism ; Aspergillus flavus/*metabolism ; Bacillus cereus/*metabolism ; *Biodegradation, Environmental ; *Biofilms ; DNA, Intergenic/genetics ; Gas Chromatography-Mass Spectrometry ; Microbiota ; RNA, Ribosomal, 16S/genetics ; }, abstract = {BACKGROUND: The hydrophobic nature of hydrocarbons make them less bioavailable to microbes, generally leading to low efficiency in biodegradation. Current bioremediation strategies for hydrocarbon contamination, uses induced mixed microbial cultures. This in-vitro study demonstrates the utilization of naturally occurring communities in suitable habitats for achieving highly efficient, synergistic degradation of hydrocarbons in a simple community structure without additives.

METHODS: Enrichment media supplemented with 1% (7652.53 mg/L) hexadecane (HXD) as the sole carbon source were inoculated with samples of soil with waste polythene, collected from a municipal landfill in order to isolate microbial communities. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed on HXD grown co-cultures and individual counterparts after 14 days incubation and percentage degradation was calculated. Microbes were identified using 16S rRNA gene and Internal Transcribed Spacer region sequencing. Biofilm formation was confirmed through scanning electron microscopy, in the most efficient community.

RESULTS: Three mixed communities (C1, C2 and C3) that demonstrated efficient visual disintegration of the HXD layer in the static liquid cultures were isolated. The C1 community showed the highest activity, degrading > 99% HXD within 14 days. C1 comprised of a single fungus and a bacterium and they were identified as a Bacillus sp. MM1 and an Apsergillus sp. MM1. The co-culture and individual counterparts of the C1 community were assayed for HXD degradation by GC-MS. Degradation by the fungal and bacterial monocultures were 52.92 ± 8.81% and 9.62 ± 0.71% respectively, compared to 99.42 ± 0.38% by the co-culture in 14 days. This proved the synergistic behavior of the community. Further, this community demonstrated the formation of a biofilm in oil-water interface in the liquid medium. This was evidenced from scanning electron microscopy (SEM) showing the Bacillus cells attached on to Aspergillus mycelia.

CONCLUSIONS: This study demonstrates the utilization of naturally formed fungal-bacterial communities for enhanced biodegradation of hydrocarbons such as hexadecane and reports for the first time, synergistic degradation of hexadecane through biofilm formation, by a community comprising of Bacillus cereus group and Aspergillus flavus complex.}, } @article {pmid31034965, year = {2019}, author = {Yonezawa, H and Osaki, T and Hojo, F and Kamiya, S}, title = {Effect of Helicobacter pylori biofilm formation on susceptibility to amoxicillin, metronidazole and clarithromycin.}, journal = {Microbial pathogenesis}, volume = {132}, number = {}, pages = {100-108}, doi = {10.1016/j.micpath.2019.04.030}, pmid = {31034965}, issn = {1096-1208}, mesh = {Amoxicillin/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Clarithromycin/*pharmacology ; Drug Combinations ; Helicobacter pylori/*drug effects/genetics ; Humans ; Kinetics ; Metronidazole/*pharmacology ; Microbial Viability/drug effects ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The human gastric pathogen Helicobacter pylori forms biofilms in vitro and in vivo. We previously demonstrated that H. pylori biofilm formation in vitro decreased its susceptibility to clarithromycin (CAM). The aim of this study was to evaluate the effects of biofilm formation on amoxicillin (AMPC) and metronidazole (MNZ) susceptibility. In addition, we assessed the influence of biofilms of CAM resistant H. pylori on CAM susceptibility. It was shown that high levels of efflux pump gene transcripts were detected in biofilm cells of all H. pylori strains used in this study. H. pylori biofilm biomass was significantly decreased compared to initial biomass after treatment with the minimum inhibitory concentration (MIC) of AMPC. Similarly, the biofilm biomass of H. pylori decreased after treatment with MIC of MNZ, although the difference was not statistically significant. However, minimum bactericidal concentrations (MBCs) of AMPC or MNZ to biofilm cells were higher than those of planktonic cells. The biofilm biomasses of all of the CAM resistant strains were significantly decreased compared to initial biomass after treatment with 2x MIC of CAM. However, the viability of the CAM treated biofilm cells with 2x MIC of CAM was not significantly reduced compared to initial cell numbers with the exception of one strain. The viability of biofilm cells of all strains was higher than that of planktonic cells after treatment with various concentrations of CAM. These results indicate that biofilm cells were more resistant to these antibiotics than planktonic cells and that the assessment of the ability to form biofilms in H. pylori is important for eradication of this microorganism.}, } @article {pmid31034083, year = {2019}, author = {Bernardi, S and Continenza, MA and Al-Ahmad, A and Karygianni, L and Follo, M and Filippi, A and Macchiarelli, G}, title = {Streptococcus spp. and Fusobacterium nucleatum in tongue dorsum biofilm from halitosis patients: a fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) study.}, journal = {The new microbiologica}, volume = {42}, number = {2}, pages = {108-113}, pmid = {31034083}, issn = {1121-7138}, mesh = {*Biofilms ; *Fusobacterium nucleatum/physiology ; *Halitosis/microbiology ; Humans ; In Situ Hybridization, Fluorescence ; Microscopy, Confocal ; *Streptococcus/physiology ; *Tongue/microbiology ; }, abstract = {The present study involved a qualitative and quantitative evaluation of tongue dorsum biofilms sampled from halitosis patients and healthy volunteers. The aim of the study was to quantify the distribution of Streptococcus spp. and Fusobacterium nucleatum within the oral halitosis biofilm in order to highlight the role of these bacterial members in halitosis. Tongue plaque samples from four halitosis-diagnosed patients and four healthy volunteers were analyzed and compared. The visualization and quantification of the tongue dorsum biofilm was performed combining fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). Eubacteria, Streptococcus spp. and Fusobacterium nucleatum were stained using specific fluorescent probes. For a comparison of the two tested biofilm groups the Wilcoxon rank-sum test was used. Morphological analysis by CLSM illustrated the distribution of the species which were tracked. Streptococcus spp. appeared to be enclosed within the samples and always associated to F. nucleatum. Furthermore, compared to the control group the biofilm within the halitosis group contained significantly higher proportions of F. nucleatum and Streptococcus spp., as revealed by the FISH and CLSM-analysis. The total microbial load and relative proportions of F. nucleatum and Streptococcus spp. can be considered as causative factors of halitosis and thus, as potential treatment targets.}, } @article {pmid31033962, year = {2019}, author = {Danikowski, KM and Cheng, T}, title = {Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {146}, pages = {}, doi = {10.3791/59285}, pmid = {31033962}, issn = {1940-087X}, mesh = {Alkaline Phosphatase/*metabolism ; *Biofilms ; Colorimetry/*methods ; Hydrolysis ; Nitrophenols/metabolism ; Organophosphorus Compounds/metabolism ; Staphylococcus aureus/*enzymology/*physiology ; Substrate Specificity ; }, abstract = {Alkaline phosphatase (ALP) is a common enzyme expressed in both prokaryotic and eukaryotic cells. It catalyzes the hydrolysis of phosphate monoesters from many molecules at basic pH and plays an indispensable role in phosphate metabolism. In humans, eukaryotic ALP is one of the most frequently used enzymatic signals in diagnosing various diseases, such as cholestasis and rickets. In S. aureus, ALP is detected exclusively on the cell membrane; it is also expressed as a secretory form as well. Yet, little is known about its function in biofilm formation. The purpose of this manuscript is to develop a quick and reliable assay to measure ALP activity in S. aureus biofilm that does not require protein isolation. Using p-nitrophenyl phosphate (pNPP) as a substrate, we measured ALP activity in S. aureus biofilm formed in 96-well tissue culture plates. Activity was based on the formation of the soluble reaction product measured by 405 nm absorbance. The high throughput nature of the 96 well tissue culture plate method provides a sensitive and reproducible method for ALP activity assays. The same experimental set up can also be extended to measure other extracellular molecular markers related to biofilm formation.}, } @article {pmid31033283, year = {2019}, author = {Benoit, DSW and Sims, KR and Fraser, D}, title = {Nanoparticles for Oral Biofilm Treatments.}, journal = {ACS nano}, volume = {13}, number = {5}, pages = {4869-4875}, pmid = {31033283}, issn = {1936-086X}, support = {F31 DE026944/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Catalysis ; Humans ; Mouth/*microbiology ; Nanoparticles/*chemistry ; }, abstract = {Pathogenic oral biofilms are universal, chronic, and costly. Despite advances in understanding the mechanisms of biofilm formation and persistence, novel and effective treatment options remain scarce. Nanoparticle-mediated eradication of the biofilm matrix and resident bacteria holds great potential. In particular, nanoparticles that target specific microbial and biofilm features utilizing nontoxic materials are well-suited for clinical translation. However, much work remains to characterize the local and systemic effects of therapeutic agents that are topically applied to chronic biofilms, such as those that cause dental caries. In this Perspective, we summarize the pathogenesis of oral biofilms, describe current and future nanoparticle-mediated treatment approaches, and highlight outstanding questions that are paramount to answer for effectively targeting and treating oral biofilms.}, } @article {pmid31033028, year = {2019}, author = {Tuna, T and Kuhlmann, L and Bishti, S and Sirazitdinova, E and Deserno, T and Wolfart, S}, title = {Removal of simulated biofilm at different implant crown designs with interproximal oral hygiene aids: An in vitro study.}, journal = {Clinical oral implants research}, volume = {30}, number = {7}, pages = {627-636}, doi = {10.1111/clr.13448}, pmid = {31033028}, issn = {1600-0501}, mesh = {Biofilms ; Crowns ; Dental Devices, Home Care ; *Dental Plaque ; Humans ; *Oral Hygiene ; }, abstract = {OBJECTIVES: To compare the removal of simulated biofilm at two different implant-supported restoration designs with various interproximal oral hygiene aids.

METHODS: Mandibular models with a missing first molar were fabricated and provided with single implant analogues (centrally or distally placed) and two different crown designs (conventional [CCD] and alternative crown design [ACD]). Occlusion spray was applied to the crowns to simulate artificial biofilm. Thirty participants (dentists, dental hygienists, and laypersons) were equally divided and asked to clean the interproximal areas with five different cleaning devices to further evaluate if there were differences in their cleaning ability. The outcome was measured via standardized photos and the cleaning ratio, representing the cleaned surfaces in relation to the respective crown surface. Statistical analysis was performed by linear mixed-effects model with fixed effects for cleaning tools, surfaces, crown design and type of participant, and random effects for crowns.

RESULTS: The mean cleaning ratio for the investigated tools and crown designs were (in%): Super floss: 76 ± 13/ACD and 57 ± 14/CCD (highest cleaning efficiency), followed by dental floss: 66 ± 13/ACD and 56 ± 15/CCD, interdental brush: 55 ± 10/ACD and 45 ± 9/CCD, electric interspace brush: 31 ± 10/ACD and 30 ± 1/CCD, microdroplet floss: 8 ± 9/ACD and 9 ± 8/CCD. There was evidence of an overall effect of each factor "cleaning tool," "surface," "crown design," and "participant" (p < 0.0001).

CONCLUSIONS: ACD allowed more removal of the artificial biofilm than CCD with Super floss, dental floss, and interdental brush. Flossing and interproximal brushing were the most effective cleaning methods. A complete removal of the artificial biofilm could not be achieved in any group.}, } @article {pmid31031431, year = {2019}, author = {Bhatwalkar, SB and Gound, SS and Mondal, R and Srivastava, RK and Anupam, R}, title = {Anti-biofilm and Antibacterial Activity of Allium sativum Against Drug Resistant Shiga-Toxin Producing Escherichia coli (STEC) Isolates from Patient Samples and Food Sources.}, journal = {Indian journal of microbiology}, volume = {59}, number = {2}, pages = {171-179}, pmid = {31031431}, issn = {0046-8991}, abstract = {Escherichia coli (E. coli) colonizes human intestinal tract and is usually harmless to the host. However, several strains of E. coli have acquired virulent genes and could cause enteric diseases, urinary tract and even brain infections. Shiga toxin producing Escherichia coli (STEC) is an enterohaemorrhagic E. coli (EHEC) which can result in bloody diarrhoea and could potentially lead to deadly heamolytic uremic syndrome (HUS). STEC is one of the important food borne pathogens that causes food poisoning leading to diarrhoea and number of STEC outbreaks have occurred across the world. The use of standard antibiotics to treat STEC infection is not recommended as it increases the production of shiga toxin which could lead to HUS. Therefore, use of alternative approaches which include use of plant products to treat STEC infections have been gaining attention. The objective of this study was to evaluate the antibacterial and anti-biofilm activity of garlic (Allium sativum) against STEC strains isolated from various patient and food samples using in vitro assays. The microbiological isolation of STEC from various patient and food samples resulted in eight STEC isolates of which seven strains were multidrug resistant. Antibacterial assay results indicated that all the strains exhibited dose dependent sensitivity towards garlic with zone of inhibition diameters ranging from 7 to 24 mm with 15 µl of fresh garlic extract (FGE). Minimum inhibitory concentration (MIC) of FGE for isolates ranged from 30 to 140 µl/ml. Interestingly, the biofilm formation of all isolates in presence of 4% of FGE decreased by 35 to 59%. FTIR analysis indicated that treatment with 1% FGE results in compositional and content changes in the biofilm. In addition, the total carbohydrate content of biofilm was reduced by 40% upon 1% FGE treatment. The results of the present study report for the first time the antibacterial and anti-biofilm activity of garlic against STEC. The findings will enable development of novel garlic organosulfide based drugs for the prevention and treatment of STEC infections.}, } @article {pmid31029662, year = {2019}, author = {Noverr, MC and Fidel, PL}, title = {Questions remain regarding the presence of fungal species biofilm in women with vulvovaginal candidiasis.}, journal = {American journal of obstetrics and gynecology}, volume = {221}, number = {2}, pages = {169}, doi = {10.1016/j.ajog.2019.04.017}, pmid = {31029662}, issn = {1097-6868}, mesh = {Biofilms ; *Candidiasis, Vulvovaginal ; Drug Resistance, Fungal ; Female ; Humans ; }, } @article {pmid31029348, year = {2019}, author = {Daengngam, C and Lethongkam, S and Srisamran, P and Paosen, S and Wintachai, P and Anantravanit, B and Vattanavanit, V and Voravuthikunchai, S}, title = {Green fabrication of anti-bacterial biofilm layer on endotracheal tubing using silver nanoparticles embedded in polyelectrolyte multilayered film.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {101}, number = {}, pages = {53-63}, doi = {10.1016/j.msec.2019.03.061}, pmid = {31029348}, issn = {1873-0191}, mesh = {A549 Cells ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Death/drug effects ; Cell Shape/drug effects ; Green Chemistry Technology/*methods ; Humans ; *Intubation, Intratracheal ; Metal Nanoparticles/*chemistry/ultrastructure ; Microbial Sensitivity Tests ; Plasma Gases/pharmacology ; Polyelectrolytes/*pharmacology ; Pseudomonas aeruginosa/drug effects/growth & development/physiology ; Silver/*pharmacology ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/drug effects/growth & development/physiology ; Wettability ; }, abstract = {Endotracheal tubes (ETTs) are a common source of bacterial colonization, leading to ventilator-associated pneumonia (VAP). This research developed a biofilm-resistant ETT, following the principles of green chemistry. Using an aqueous layer-by-layer (LbL) technique, a thick polyelectrolyte multilayered film was deposited on a ventilation tube. The polyelectrolyte multilayered film accommodated silver nanoparticles (AgNPs) formed in situ by reducing Ag[+] ions with Eucalyptus citriodora leaf extract. The multilayered film coating conformed to the curved surfaces of the ETT. Film thickness and silver content increased exponentially with the number of polyelectrolyte bilayer pairs, and a sufficiently high AgNPs content of 10-30%w/w was obtained at 75 to 125 bilayer films. Adhesion of the Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was prevented by 99.9 and 99.99%, respectively, without cytotoxic effects against human lung epithelial cells (p < 0.05).}, } @article {pmid31028534, year = {2019}, author = {Perez-Tanoira, R and Aarnisalo, A and Haapaniemi, A and Saarinen, R and Kuusela, P and Kinnari, TJ}, title = {Bacterial biofilm in salivary stones.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {276}, number = {6}, pages = {1815-1822}, pmid = {31028534}, issn = {1434-4726}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; *Biofilms ; Child ; Endoscopy/*adverse effects ; Female ; Humans ; Male ; Middle Aged ; Postoperative Complications/*epidemiology ; Prospective Studies ; Salivary Gland Calculi/complications/*microbiology/surgery ; Treatment Outcome ; Young Adult ; }, abstract = {PURPOSE: To assess the susceptibility of salivary stones to bacterial biofilm formation, which may be involved in the development of salivary gland infection, and to investigate a relation between microbiological aspects and patient characteristics.

METHODS: This prospective study comprises of 54 patients with sialolithiasis attended in Helsinki University Hospital during 2014-2016. A total of 55 salivary stones were removed, and studied for biofilm formation using fluorescence microscopy and sonication. The isolated organisms were quantified and identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

RESULTS: Biofilm formation was confirmed on the surface of 39 (70.9%) stones. A total of 96 microorganisms were isolated from 45 salivary stones (81.8%). Two or more organisms were isolated in 33 (73.3%) cases. The main isolates were Streptococcus mitis/oralis (n = 27; 28.1%), followed by Streptococcus anginosus (n = 10; 9.6%), Rothia spp. (n = 8; 8.3%), Streptococcus constellatus (n = 7; 7.3%), and Streptococcus gordonii (n = 6; 6.2%). In all patients showing pre-operative (12 cases) or peri-operative (three cases) drainage of pus, the presence of biofilm was detected in microscopy (p = 0.004). Four patients showed post-operative infection, and in three of them (75.0%), the presence of biofilm was detected. Increased number of pus drainage was found among patients with reflux symptoms or use of proton-pump inhibitors.

CONCLUSIONS: Salivary stones are susceptible to bacterial biofilm formation, which could be related with the development and severity of the inflammation and the refractory nature of the disease. Sonication of salivary gland stones could be a useful method for finding the etiology of the chronic infection.}, } @article {pmid31027789, year = {2019}, author = {Ostrov, I and Sela, N and Belausov, E and Steinberg, D and Shemesh, M}, title = {Adaptation of Bacillus species to dairy associated environment facilitates their biofilm forming ability.}, journal = {Food microbiology}, volume = {82}, number = {}, pages = {316-324}, doi = {10.1016/j.fm.2019.02.015}, pmid = {31027789}, issn = {1095-9998}, mesh = {*Adaptation, Physiological/genetics ; Animals ; Bacillus/classification/genetics/growth & development/*physiology ; Biofilms/*growth & development ; Cluster Analysis ; DNA, Bacterial/genetics ; Food Microbiology ; Genes, Bacterial/genetics ; Genetic Variation ; Genome, Bacterial/genetics ; Milk/*microbiology ; Sequence Analysis, DNA ; }, abstract = {Biofilm-forming Bacillus species are often involved in contamination of dairy products and therefore present a major microbiological challenge in the field of food quality and safety. In this study, we sequenced and analyzed the genomes of milk- and non-milk-derived Bacillus strains, and evaluated their biofilm-formation potential in milk. Unlike non-dairy Bacillus isolates, the dairy-associated Bacillus strains were characterized by formation of robust submerged and air-liquid interface biofilm (pellicle) during growth in milk. Moreover, genome comparison analysis revealed notable differences in putative biofilm-associated determinants between the dairy and non-dairy Bacillus isolates, which correlated with biofilm phenotype. These results suggest that biofilm formation by Bacillus species might represent a presumable adaptation strategy to the dairy environment.}, } @article {pmid31027768, year = {2019}, author = {Pang, X and Yuk, HG}, title = {Effects of the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens on survival of biofilm cells under food-related stresses and transfer to salmon.}, journal = {Food microbiology}, volume = {82}, number = {}, pages = {142-150}, doi = {10.1016/j.fm.2019.02.002}, pmid = {31027768}, issn = {1095-9998}, mesh = {Animals ; Bacterial Adhesion ; *Biofilms ; Colony Count, Microbial ; Desiccation ; Disinfectants/pharmacology ; Disinfection ; *Food Microbiology ; Food-Processing Industry ; Listeria monocytogenes/drug effects/*physiology ; Polysaccharides, Bacterial/biosynthesis ; Pseudomonas fluorescens/drug effects/*physiology ; Salmon/*microbiology ; Seafood/*microbiology ; }, abstract = {This study evaluated how the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens affects biofilm formation and biofilm cell response to food-related stress (desiccation or disinfection) as well as the transferability of L. monocytogenes to salmon products. The results showed that the colonization sequence did not affect the population of dual species biofilms. Furthermore, survival number of L. monocytogenes was 0.8 log CFU/cm[2] higher when P. fluorescens was the first colonizer during desiccation or disinfectant treatment in comparison with dual-species biofilms with other colonization sequences. A lower transfer rate of L. monocytogenes biofilm cells from dual-species biofilms was observed as compared to single species biofilms. In particular, L. monocytogenes cells detached at a slower rate during transfer to 10 slices of salmon from dual-species biofilms first established by P. fluorescens. Confocal images revealed more exopolysaccharide production in dual-speciesbiofilms first established by P. fluorescens than in biofilms generated via other sequences. These results indicate that preexisting P. fluorescens biofilms on stainless steel can enhance resistance of L. monocytogenes to desiccation and disinfection, although this setup decreased the transfer rate of L. monocytogenes to salmon slices. Thus, this study highlights the risk of L. monocytogenes contamination in pre-formed Pseudomonas biofilms at salmon processing facilities.}, } @article {pmid31025881, year = {2019}, author = {Rebrošová, K and Šiler, M and Samek, O and Růžička, F and Bernatová, S and Ježek, J and Zemánek, P and Holá, V}, title = {Identification of ability to form biofilm in Candida parapsilosis and Staphylococcus epidermidis by Raman spectroscopy.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {509-517}, doi = {10.2217/fmb-2018-0297}, pmid = {31025881}, issn = {1746-0921}, mesh = {Biofilms/*growth & development ; Candida parapsilosis/*metabolism ; Diagnostic Tests, Routine/methods ; Humans ; Spectrum Analysis, Raman/*methods ; Staphylococcus epidermidis/*metabolism ; }, abstract = {Aim: Finding rapid, reliable diagnostic methods is a big challenge in clinical microbiology. Raman spectroscopy is an optical method used for multiple applications in scientific fields including microbiology. This work reports its potential in identifying biofilm positive strains of Candida parapsilosis and Staphylococcus epidermidis. Materials & methods: We tested 54 S. epidermidis strains (23 biofilm positive, 31 negative) and 51 C. parapsilosis strains (27 biofilm positive, 24 negative) from colonies on Mueller-Hinton agar plates, using Raman spectroscopy. Results: The accuracy was 98.9% for C. parapsilosis and 96.1% for S. epidermidis. Conclusion: The method showed great potential for identifying biofilm positive bacterial and yeast strains. We suggest that Raman spectroscopy might become a useful aid in clinical diagnostics.}, } @article {pmid31025575, year = {2019}, author = {Gazzola, G and Habimana, O and Quinn, L and Casey, E and Murphy, CD}, title = {Population dynamics of a dual Pseudomonas putida-Pseudomonas fluorescens biofilm in a capillary bioreactor.}, journal = {Biofouling}, volume = {35}, number = {3}, pages = {299-307}, doi = {10.1080/08927014.2019.1598397}, pmid = {31025575}, issn = {1029-2454}, mesh = {*Biofilms/growth & development ; Bioreactors/*microbiology ; Pseudomonas fluorescens/*physiology ; Pseudomonas putida/*physiology ; }, abstract = {Most biofilm studies employ single species, yet in nature biofilms exist as mixed cultures, with inevitable effects on growth and development of each species present. To investigate how related species of bacteria interact in biofilms, two Pseudomonas spp., Pseudomonas fluorescens and Pseudomonas putida, were cultured in capillary bioreactors and their growth measured by confocal microscopy and cell counting. When inoculated in pure culture, both bacteria formed healthy biofilms within 72 h with uniform coverage of the surface. However, when the bioreactors were inoculated with both bacteria simultaneously, P. putida was completely dominant after 48 h. Even when the inoculation by P. putida was delayed for 24 h, P. fluorescens was eliminated from the capillary within 48 h. It is proposed that production of the lipopeptide putisolvin by P. putida is the likely reason for the reduction of P. fluorescens. Putisolvin biosynthesis in the dual-species biofilm was confirmed by mass spectrometry.}, } @article {pmid31024468, year = {2019}, author = {Abdel-Nour, M and Su, H and Duncan, C and Li, S and Raju, D and Shamoun, F and Valton, M and Ginevra, C and Jarraud, S and Guyard, C and Kerman, K and Terebiznik, MR}, title = {Polymorphisms of a Collagen-Like Adhesin Contributes to Legionella pneumophila Adhesion, Biofilm Formation Capacity and Clinical Prevalence.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {604}, pmid = {31024468}, issn = {1664-302X}, abstract = {Legionellosis is a severe respiratory illness caused by the inhalation of aerosolized water droplets contaminated with the opportunistic pathogen Legionella pneumophila. The ability of L. pneumophila to produce biofilms has been associated with its capacity to colonize and persist in human-made water reservoirs and distribution systems, which are the source of legionellosis outbreaks. Nevertheless, the factors that mediate L. pneumophila biofilm formation are largely unknown. In previous studies we reported that the adhesin Legionella collagen-like protein (Lcl), is required for auto-aggregation, attachment to multiple surfaces and the formation of biofilms. Lcl structure contains three distinguishable regions: An N-terminal region with a predicted signal sequence, a central region containing tandem collagen-like repeats (R-domain) and a C-terminal region (C-domain) with no significant homology to other known proteins. Lcl R-domain encodes tandem repeats of the collagenous tripeptide Gly-Xaa-Yaa (GXY), a motif that is key for the molecular organization of mammalian collagen and mediates the binding of collagenous proteins to different cellular and environmental ligands. Interestingly, Lcl is polymorphic in the number of GXY tandem repeats. In this study, we combined diverse biochemical, genetic, and cellular approaches to determine the role of Lcl domains and GXY repeats polymorphisms on the structural and functional properties of Lcl, as well as on bacterial attachment, aggregation and biofilm formation. Our results indicate that the R-domain is key for assembling Lcl collagenous triple-helices and has a more preponderate role over the C-domain in Lcl adhesin binding properties. We show that Lcl molecules oligomerize to form large supramolecular complexes to which both, R and C-domains are required. Furthermore, we found that the number of GXY tandem repeats encoded in Lcl R-domain correlates positively with the binding capabilities of Lcl and with the attachment and biofilm production capacity of L. pneumophila strains. Accordingly, the number of GXY tandem repeats in Lcl influences the clinical prevalence of L. pneumophila strains. Therefore, the number of Lcl tandem repeats could be considered as a potential predictor for virulence in L. pneumophila isolates.}, } @article {pmid31023592, year = {2019}, author = {Król, J and Nawrot, U and Bartoszewicz, M}, title = {Activity of base analogues (5-fluorouracil, 5-flucytosine) against planktonic cells and mature biofilm of Candida yeast. Effect of combination with folinic acid.}, journal = {Journal de mycologie medicale}, volume = {29}, number = {2}, pages = {147-153}, doi = {10.1016/j.mycmed.2019.04.003}, pmid = {31023592}, issn = {1773-0449}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Candida glabrata/*drug effects ; Candidiasis/drug therapy ; Drug Resistance, Fungal ; Flucytosine/*pharmacology ; Fluorouracil/*pharmacology ; Gentian Violet ; Leucovorin/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {BACKGROUND: The increasing number of Candida infections, especially those caused by non-C. albicans species and resistant strains, is a serious medical problem.

OBJECTIVES: In this study, the antifungal activity of base analogues, 5-flucytosine (5-FC) and 5-fluorouracil (5-FU), was tested against planktonic cells as well as against mature biofilm.

METHODS: Tests were performed according the EUCAST methodology. Antibiofilm effectiveness of tested drugs was determined by the crystal violet staining method. The cytotoxicity assays was performed according to the ISO 10993-5 norm.

RESULTS: 5-FC and 5-FU were effective against fifteen fluconazole resistant Candida glabrata strains with an average minimal inhibitory concentration (MIC) of 0.152mg/L and 0.39mg/L, respectively. Folinic acid (folinate- e.g., leucovorin) is a common drug used in oncology simultaneously with 5-FU. In our tests folinate was able to lower MIC for 5-FC from 0.152 to 0.058mg/L (P<0.05). In the biofilm assay 5-FU and 5-FC alone did not induce any changes in the biomass of mature biofilm. Addition of folinate to each base analogue resulted in up to 90% reduction of biomass. Viability tests show that a concentration of 64mg/L of 5-FC and 5-FU supplemented with folinate can be fungicidal against mature biofilms of some Candida isolates. No cytotoxic effect was found for combination of FOL and 5-FC.

CONCLUSION: Therapy of 5-FU+folinate is well known in cancer treatment, in this study we reveal the beneficial effect of folinate on antifungal activity of 5-FC as well as the antifungal potential of 5-FU+folinate.}, } @article {pmid31022836, year = {2019}, author = {Flockton, TR and Schnorbus, L and Araujo, A and Adams, J and Hammel, M and Perez, LJ}, title = {Inhibition of Pseudomonas aeruginosa Biofilm Formation with Surface Modified Polymeric Nanoparticles.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {31022836}, issn = {2076-0817}, abstract = {The gram-negative bacterial pathogen Pseudomonas aeruginosa represents a prominent clinical concern. Due to the observed high levels of antibiotic resistance, copious biofilm formation, and wide array of virulence factors produced by these bacteria, new treatment technologies are required. Here, we present the development of a series of P. aeruginosa LecA-targeted polymeric nanoparticles and demonstrate the anti-adhesion and biofilm inhibitory properties of these constructs.}, } @article {pmid31022421, year = {2019}, author = {Maktabi, H and Ibrahim, M and Alkhubaizi, Q and Weir, M and Xu, H and Strassler, H and Fugolin, APP and Pfeifer, CS and Melo, MAS}, title = {Underperforming light curing procedures trigger detrimental irradiance-dependent biofilm response on incrementally placed dental composites.}, journal = {Journal of dentistry}, volume = {88}, number = {}, pages = {103110}, doi = {10.1016/j.jdent.2019.04.003}, pmid = {31022421}, issn = {1879-176X}, mesh = {Bacterial Adhesion ; Biofilms/*radiation effects ; Composite Resins/chemistry/*radiation effects ; *Curing Lights, Dental ; Dental Materials ; Humans ; Light-Curing of Dental Adhesives/*methods ; Materials Testing ; Solubility ; Streptococcus mutans ; Water/chemistry ; }, abstract = {OBJECTIVES: Insufficient radiant exposure (J/cm[2]) may provide an early trigger in a cascade of detrimental responses on incrementally-place composite, especially the bottom layer. This study aimed to assess the influence of poor radiant exposure, the degree of conversion (%DC), water sorption/ solubility and S. mutans biofilm formation on conventional, incrementally placed composites and to establish a relationship between these factors.

METHODS: Two light units operating at 600 and 1000 mW/cm[2] and four most common operator-dependent curing conditions had the radiant exposure (RE) recorded. All the specimens were subjected to S. mutans biofilm model for 14 days. The %DC, biofilm formation expressed by colony-forming units (CFU), water sorption/ solubility and surface roughness/ SEM were assessed. Data were submitted to two-way ANOVA and Tukey post-hoc test (α = 0.05). Pearson correlation was also determined.

RESULTS: The influence of RE on S. mutans CFU values and DC are dependent on the curing conditions and irradiance (p < 0.05). A negative relationship was observed between RE and biofilm formation. The operator-dependent curing conditions have shown RE reduction varying from 49.4% to 73.5% in relation to control. The difference in DC between top/bottom of cylinder varied from 13% to 21% for 1000 mW/cm[2]and from 29% to 53% for LCU600. The roughness, solubility and salivary sorption were greater for low RE.

CONCLUSION: Poor, deficient curing procedures provide an early trigger in a negative pathway of events for incrementally-place dental composite including a biological response by increased biofilm formation by S. mutans, a relevant factor for secondary caries development.

SIGNIFICANCE: The susceptibility to variation in the outcomes was RE -dependent. The optimization of the curing procedures ensures the maximum performance in the chain of events involved in the light curing process of resin-based materials and potentially reduce the risk factors of secondary caries development.}, } @article {pmid31021431, year = {2020}, author = {Barron, CL and Kamel-Abusalha, LB and Sethia, R and Goodman, SD and Elmaraghy, CA and Bakaletz, LO}, title = {Identification of essential biofilm proteins in middle ear fluids of otitis media with effusion patients.}, journal = {The Laryngoscope}, volume = {130}, number = {3}, pages = {806-811}, pmid = {31021431}, issn = {1531-4995}, support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {Adolescent ; Bacterial Proteins/*analysis ; Bacterial Structures ; *Biofilms ; Child ; Child, Preschool ; Exudates and Transudates/*chemistry/microbiology ; Female ; Humans ; Infant ; Male ; *Otitis Media with Effusion/microbiology ; Young Adult ; }, abstract = {OBJECTIVES: Otitis media with effusion (OME) is a common disease of childhood that is largely asymptomatic. However, middle ear fluid can persist for months and negatively impact a child's quality of life. Many cases of OME remain chronic and require surgical intervention. Because biofilms are known to contribute to the persistence of many diseases, this study examined effusions collected from children with chronic OME for the presence of essential biofilm structural components, members of the DNABII family of bacterial DNA-binding proteins.

METHODS: Middle ear effusions were recovered from 38 children with chronic OME at the time of tympanostomy tube insertion. A portion of each specimen was submitted for microbiology culture. The remaining material was assessed by immunoblot to quantitate individual DNABII proteins, integration host factor (IHF), and histone-like protein (HU).

RESULTS: Sixty-five percent of effusions (24 of 37) were culture-positive for bacterial species or yeast, whereas 35% (13 of 37) were culture-negative. IHF was detected in 95% (36 of 38) at concentrations from 2 to 481 ng/μL effusion. HU was detected in 95% (36 of 38) and quantitated from 13 to 5,264 ng/μL effusion (P ≤ 0.05 compared to IHF).

CONCLUSION: Because DNABII proteins are essential structural components of bacterial biofilms, these data lend further support to our understanding that biofilms are present in the vast majority of chronic middle ear effusions, despite negative culture results. The presence and ubiquity of DNABII proteins in OME specimens indicated that these proteins can serve as an important clinical target for our novel DNABII-directed strategy to treat biofilm diseases such as chronic OME.

LEVEL OF EVIDENCE: NA Laryngoscope, 130:806-811, 2020.}, } @article {pmid31021332, year = {2019}, author = {Gómez-Gómez, B and Arregui, L and Serrano, S and Santos, A and Pérez-Corona, T and Madrid, Y}, title = {Selenium and tellurium-based nanoparticles as interfering factors in quorum sensing-regulated processes: violacein production and bacterial biofilm formation.}, journal = {Metallomics : integrated biometal science}, volume = {11}, number = {6}, pages = {1104-1114}, doi = {10.1039/c9mt00044e}, pmid = {31021332}, issn = {1756-591X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Chromobacterium/*drug effects/physiology ; Humans ; Indoles/*metabolism ; Nanoparticles/chemistry ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects ; Selenium/chemistry/*pharmacology ; Tellurium/chemistry/*pharmacology ; }, abstract = {A cell-to-cell communication system called quorum sensing (QS) promotes the transcription of certain target genes in bacterial cells leading to the activation of different cellular processes, some of them related to bacterial biofilm formation. The formation of bacterial biofilms favours antibiotic resistance, which is nowadays a significant public-health problem. In this study, the effect of selenium (SeNPs) and tellurium (TeNPs) nanoparticles was examined in two bacterial processes mediated by QS: violacein production by Chromobacterium violaceum and biofilm formation by Pseudomonas aeruginosa. For this purpose, quantification of the pigment production in the presence of these nanoparticles was monitored using the C. violaceum strain. Additionally, a combination of different microscopical imaging techniques was applied to examine the changes in the 3D biofilm structure of P. aeruginosa, which were quantified through performing architectural metric calculations (substratum area, cell area coverage and biovolume). SeNPs produce an 80% inhibition in the violacein production by C. violaceum and a significant effect on the P. aeruginosa biofilm architecture (a reduction of 80% in the biovolume of the bacterial biofilm was obtained). TeNPs similarly affect violacein production and the P. aeruginosa biofilm structure but at lower concentration levels. The results obtained suggest an important disruption of the QS signalling system by SeNPs and TeNPs, supporting nanotechnology as a promising tool to fight against the emerging problem of bacterial resistance related to bacterial biofilm formation.}, } @article {pmid31021282, year = {2019}, author = {Yang, Y and Hwang, EH and Park, BI and Choi, NY and Kim, KJ and You, YO}, title = {Artemisia princeps Inhibits Growth, Biofilm Formation, and Virulence Factor Expression of Streptococcus mutans.}, journal = {Journal of medicinal food}, volume = {22}, number = {6}, pages = {623-630}, doi = {10.1089/jmf.2018.4304}, pmid = {31021282}, issn = {1557-7600}, mesh = {Anti-Bacterial Agents/*pharmacology ; Artemisia/*chemistry ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Streptococcus mutans/*drug effects/*genetics/growth & development/physiology ; Virulence Factors/*genetics/metabolism ; }, abstract = {This study was designed to determine whether the ethanol extract of Artemisia princeps could inhibit the cariogenic activity of Streptococcus mutans. The increase in acid production and biofilm formation by S. mutans were evaluated. The expression levels of virulence factor genes were determined by performing the real-time polymerase chain reaction (PCR). The bactericidal effect was tested by confocal laser scanning microscopy. The A. princeps extract was observed to inhibit the growth of S. mutans at concentrations >0.05 mg/mL (P < .05). After using the safranin staining method, we found that the A. princeps extract had an inhibitory effect against biofilm formation at a concentration of >0.05 mg/mL. These experimental results were similar to that observed with the scanning electron microscopy. The results of the confocal microscopy revealed that the A. princeps extract at high concentrations of 0.4-3.2 mg/mL showed a bactericidal effect in a concentration-dependent manner. According to the results of the real-time PCR analysis, it was observed that the A. princeps extract inhibited the expression of virulence factor genes. These results suggest that A. princeps may inhibit the cariogenic activity of S. mutans, and may be useful as an anticariogenic agent.}, } @article {pmid31020511, year = {2019}, author = {Li, X and Zhang, X and Zhao, X and Yu, B and Weng, L and Li, Y}, title = {Efficient Removal of Metolachlor and Bacterial Community of Biofilm in Bioelectrochemical Reactors.}, journal = {Applied biochemistry and biotechnology}, volume = {189}, number = {2}, pages = {384-395}, doi = {10.1007/s12010-019-03014-0}, pmid = {31020511}, issn = {1559-0291}, support = {2017YFD0800704//National Key R&D Program of China/ ; 41601536 and 31500425//National Natural Science Foundation of China/ ; 16JCQNJC08800//Natural Science Foundation of Tianjin city of China/ ; 2017-05//Opening Foundation of Ministry of Education of China Key Laboratory of Pollution Processes and Environmental Criteria/ ; 2017-2018//Central Public-interest Scientific Institution Basal Research Fund/ ; }, mesh = {Acetamides/*metabolism ; Bacteria/*metabolism ; *Bacterial Physiological Phenomena ; Bioelectric Energy Sources/*microbiology ; *Biofilms ; }, abstract = {The microbial fuel cell (MFC) provides an inexhaustible electron acceptor to generate current and enhance the degradation of organic compounds. In MFCs with metolachlor as the sole carbon source, the degradation efficiency accelerated by 98%, with 61-76% of enhancement for the degradates, ethane sulfonic acid and oxanilic acid, respectively. According to quantifying primary metabolites of deschloro and metolachlor-2-hydroxyas, dechlorination and alcoholization were deemed as antecedent steps of metolachlor bioelectrochemical degradation. The energy recovery was infeasible by sole addition of metolachlor (at 13 ± 4 °C from equivalent weight of 0.224 mg). In MFCs with metolachlor and sodium acetate as the concomitant carbon sources, the electricity generation recovered to a level comparable to the controls, instead of increasing the removal efficiency of metolachlor. These results suggest that a low-efficiently direct electron transfer occurred between electricigens and metolachlor degraders. The Illumina sequencing showed that species of Paracoccus and Aquamicrobium played a potential degradation effect, while Comamonas sp. replaced Geobacter sp. as the predominant electricigen after addition of metolachlor. This study demonstrates that MFCs could be used as a promising alternative for treatment of chloroacetanilide herbicide contaminated wastewaters by means of a rapidly established active bacterial community. Graphical Abstract .}, } @article {pmid31020467, year = {2019}, author = {Özcan, SS and Dieser, M and Parker, AE and Balasubramanian, N and Foreman, CM}, title = {Quorum sensing inhibition as a promising method to control biofilm growth in metalworking fluids.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {46}, number = {8}, pages = {1103-1111}, pmid = {31020467}, issn = {1476-5535}, support = {1635347//Directorate for Engineering/ ; P20GM103474//Foundation for the National Institutes of Health/ ; }, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; *Biofilms ; Extracellular Polymeric Substance Matrix/metabolism ; Furans/metabolism ; Pseudomonas aeruginosa/physiology ; *Quorum Sensing ; }, abstract = {Microbial contamination in metalworking systems is a critical problem. This study determined the microbial communities in metalworking fluids (MWFs) from two machining shops and investigated the effect of quorum sensing inhibition (QSI) on biofilm growth. In both operations, biofilm-associated and planktonic microbial communities were dominated by Pseudomonadales (60.2-99.7%). Rapid recolonization was observed even after dumping spent MWFs and meticulous cleaning. Using Pseudomonas aeruginosa PAO1 as a model biofilm organism, patulin (40 µM) and furanone C-30 (75 µM) were identified as effective QSI agents. Both agents had a substantially higher efficacy compared to α-amylase (extracellular polymeric substance degrading enzyme) and reduced biofilm formation by 63% and 76%, respectively, in MWF when compared to untreated controls. Reduced production of putatively identified homoserine lactones and quinoline in MWF treated with QS inhibitors support the effect of QSI on biofilm formation. The results highlight the effectiveness of QSI as a potential strategy to eradicate biofilms in MWFs.}, } @article {pmid31019496, year = {2019}, author = {Singh, AK and Yadav, S and Chauhan, BS and Nandy, N and Singh, R and Neogi, K and Roy, JK and Srikrishna, S and Singh, RK and Prakash, P}, title = {Classification of Clinical Isolates of Klebsiella pneumoniae Based on Their in vitro Biofilm Forming Capabilities and Elucidation of the Biofilm Matrix Chemistry With Special Reference to the Protein Content.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {669}, pmid = {31019496}, issn = {1664-302X}, abstract = {Klebsiella pneumoniae is a human pathogen, capable of forming biofilms on abiotic and biotic surfaces. The limitations of the therapeutic options against Klebsiella pneumoniae is actually due to its innate capabilities to form biofilm and harboring determinants of multidrug resistance. We utilized a newer approach for classification of biofilm producing Klebsiella pneumoniae isolates and subsequently we evaluated the chemistry of its slime, more accurately its biofilm. We extracted and determined the amount of polysaccharides and proteins from representative bacterial biofilms. The spatial distribution of sugars and proteins were then investigated in the biofilm matrix using confocal laser scanning microscopy (CLSM). Thereafter, the extracted matrix components were subjected to sophisticated analysis incorporating Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, one-dimensional gel-based electrophoresis (SDS-PAGE), high performance liquid chromatography (HPLC), and MALDI MS/MS analysis. Besides, the quantification of its total proteins, total sugars, uronates, total acetyl content was also done. Results suggest sugars are not the only/major constituent of its biofilms. The proteins were harvested and subjected to SDS-PAGE which revealed various common and unique protein bands. The common band was excised and analyzed by HPLC. MALDI MS/MS results of this common protein band indicated the presence of different proteins within the biofilm. The 55 different proteins were identified including both cytosolic and membrane proteins. About 22 proteins were related to protein synthesis and processing while 15 proteins were identified related to virulence. Similarly, proteins related to energy and metabolism were 8 and those related to capsule and cell wall synthesis were 4. These results will improve our understanding of Klebsiella biofilm composition and will further help us design better strategies for controlling its biofilm such as techniques focused on weakening/targeting certain portions of the slime which is the most common building block of the biofilm matrix.}, } @article {pmid31019240, year = {2019}, author = {Prateeksha, and Barik, SK and Singh, BN}, title = {Nanoemulsion-loaded hydrogel coatings for inhibition of bacterial virulence and biofilm formation on solid surfaces.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6520}, pmid = {31019240}, issn = {2045-2322}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Emulsions/*chemistry ; Escherichia coli O157/genetics/pathogenicity/*physiology ; Eugenol/chemistry/pharmacology ; Glass/chemistry ; Hydrogels/chemistry/*pharmacology ; Nanostructures/*chemistry ; Oils, Volatile/chemistry/pharmacology ; Salicylates/chemistry/pharmacology ; Virulence/drug effects ; }, abstract = {The indiscriminate use of antibiotics has led to the emergence of drug-resistant bacteria which has become one of the biggest challenges of the twenty-first century for the researchers to combat and in turn search for novel targets which could lead to the development of effective and sustainable therapies. Inhibition of biofilm formation and virulence of bacterial pathogens is an emerging approach to address the challenges related to bacterial infections. To suppress the virulence and biofilm formation by Escherichia coli O157:H7 (ECOH), we developed stable nanoemulsion (NE) of Gaultheria fragrantissima Wall. essential oil's (EO) bioactive compounds, viz., eugenol (E-NE) and methyl salicylate (MS-NE) that showed significantly higher anti-biofilm and anti-virulence activities as compared to eugenol and methyl salicylate without affecting ECOH planktonic cell growth. Transcriptional analysis showed that E-NE and MS-NE reduced the expression of genes, including curli, type I fimbriae, Shiga-like toxins, quorum sensing, and ler-controlled toxins, which are needed for biofilm formation, pathogenicity, and attachment. E-NE and MS-NE loaded hydrogel coatings showed superior anti-biofilm activity against ECOH on glass, plastic and meat surfaces as compared to eugenol and methyl salicylate loaded coatings. Conclusively, NE-loaded hydrogel coatings could be used in combating ECOH infection on solid surfaces through anti-biofilm and anti-virulence strategies.}, } @article {pmid31017520, year = {2019}, author = {Pandey, S and Sarkar, S}, title = {Spatial distribution of major bacterial species and different volatile fatty acids in a two-phase anaerobic biofilm reactor with PVA gel beads as bio-carrier.}, journal = {Preparative biochemistry & biotechnology}, volume = {49}, number = {7}, pages = {704-717}, doi = {10.1080/10826068.2019.1605525}, pmid = {31017520}, issn = {1532-2297}, mesh = {Anaerobiosis ; Bacteria/chemistry/*cytology/genetics ; *Biofilms ; Bioreactors/*microbiology ; Cells, Immobilized/chemistry/cytology/metabolism ; DNA, Ribosomal/genetics ; Equipment Design ; Fatty Acids, Volatile/*analysis/metabolism ; Gels/*chemistry ; Phase Transition ; Phylogeny ; Polyvinyl Alcohol/*chemistry ; Porosity ; }, abstract = {Conventional completely mixed anaerobic treatment systems limit the chances of the different species of bacteria to spatially group together according to their mutual cooperation and as a result, show a lower efficiency and vulnerability towards shock situations. It is interesting to know about the stratification of the different bacterial species participating in the degradation process and the intermediates that they produce. In this study, we established and optimized a two-phase anaerobic packed bed biofilm reactor system (AnPBR) with porous PVA gel beads used as bio-carriers and ran the reactor system in a steady state to observe the VFAs produced along with the microbial diversity of the predominant species at different stages of the reactor system. We observed that acetate and butyrate were the predominant intermediate VFAs while concentrations of other VFAs such that propionic acid were low. Acetobacterium and Clostridium were found to be the most abundant bacterial species in acidogenic reactor while methanogenic reactor was highly enriched with Methanobacterium and Methanosarcina. Apart from the above, syntrophic populations such as Syntrophobactor wolinii were also observed to be dominant in both the reactors - especially towards the end of acidogenic reactor and the initial part of the methanogenic reactor.}, } @article {pmid31015909, year = {2019}, author = {Nguyen, TV and Peszko, MT and Melander, RJ and Melander, C}, title = {Using 2-aminobenzimidazole derivatives to inhibit Mycobacterium smegmatis biofilm formation.}, journal = {MedChemComm}, volume = {10}, number = {3}, pages = {456-459}, pmid = {31015909}, issn = {2040-2511}, abstract = {Biofilm formation by mycobacteria can lead to enhanced antibiotic tolerance. Herein, we report on the identification of a series of 2-aminobenzimidazole (2-ABI) derivatives that potently inhibit biofilm formation by Mycobacterium smegmatis.}, } @article {pmid31015652, year = {2019}, author = {Tavares, ER and Gionco, B and Morguette, AEB and Andriani, GM and Morey, AT and do Carmo, AO and de Pádua Pereira, U and Andrade, G and de Oliveira, AG and Pinge-Filho, P and Nakamura, CV and Yamauchi, LM and Yamada-Ogatta, SF}, title = {Phenotypic characteristics and transcriptome profile of Cryptococcus gattii biofilm.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6438}, pmid = {31015652}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Cryptococcus gattii/*physiology/ultrastructure ; *RNA-Seq ; Transcriptome/*physiology ; }, abstract = {In this study, we characterized Cryptococcus gattii biofilm formation in vitro. There was an increase in the density of metabolically active sessile cells up to 72 h of biofilm formation on polystyrene and glass surfaces. Scanning electron microscopy and confocal laser scanning microscopy analysis revealed that in the early stage of biofilm formation, yeast cells adhered to the abiotic surface as a monolayer. After 12 h, extracellular fibrils were observed projecting from C. gattii cells, connecting the yeast cells to each other and to the abiotic surface; mature biofilm consisted of a dense network of cells deeply encased in an extracellular polymeric matrix. These features were also observed in biofilms formed on polyvinyl chloride and silicone catheter surfaces. We used RNA-Seq-based transcriptome analysis to identify changes in gene expression associated with C. gattii biofilm at 48 h compared to the free-floating planktonic cells. Differential expression analysis showed that 97 and 224 transcripts were up-regulated and down-regulated in biofilm, respectively. Among the biological processes, the highest enriched term showed that the transcripts were associated with cellular metabolic processes, macromolecule biosynthetic processes and translation.}, } @article {pmid31015181, year = {2019}, author = {Ding, X and Wei, D and Guo, W and Wang, B and Meng, Z and Feng, R and Du, B and Wei, Q}, title = {Biological denitrification in an anoxic sequencing batch biofilm reactor: Performance evaluation, nitrous oxide emission and microbial community.}, journal = {Bioresource technology}, volume = {285}, number = {}, pages = {121359}, doi = {10.1016/j.biortech.2019.121359}, pmid = {31015181}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Microbiota ; Nitrogen ; Nitrous Oxide ; }, abstract = {The present study evaluated the performance of biological denitrification in an anoxic sequencing batch biofilm reactor (ASBBR) and its nitrous oxide (N2O) emission. After 90 days operation, the effluent chemical oxygen demand and total nitrogen removal efficiencies high of 94.8% and 95.0%, respectively. Both polysaccharides and protein contents were reduced in bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) after biofilm formation. According to typical cycle, N2O release rate was related to the free nitrous acid (FNA) concentration with the maximum value of 3.88 μg/min and total conversion rate of 1.27%. Two components were identified from EEM-PARAFAC model in soluble microbial products (SMP). Protein-like substances for component 1 changed significantly in denitrification process, whereas humic-like and fulvic acid-like substances for component 2 remained relatively stable. High-throughput sequencing results showed that Lysobacter, Tolumonas and Thauera were the dominant genera, indicating the co-existence of autotrophic and heterotrophic denitrifiers in ASBBR.}, } @article {pmid31014001, year = {2019}, author = {Brust, FR and Boff, L and da Silva Trentin, D and Pedrotti Rozales, F and Barth, AL and Macedo, AJ}, title = {Macrocolony of NDM-1 Producing Enterobacter hormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {31014001}, issn = {2076-0817}, support = {1871-25511/13-4//Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul/ ; 408578/2013-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 443150/2014-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; doctoral fellowship//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 465718/2014-0//Instituto Nacional de Ciência e Tecnologia/ ; }, abstract = {Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem-rifampicin-polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.}, } @article {pmid31013388, year = {2019}, author = {Chevalier, M and Doglio, A and Rajendran, R and Ramage, G and Prêcheur, I and Ranque, S}, title = {Inhibition of adhesion-specific genes by Solidago virgaurea extract causes loss of Candida albicans biofilm integrity.}, journal = {Journal of applied microbiology}, volume = {127}, number = {1}, pages = {68-77}, doi = {10.1111/jam.14289}, pmid = {31013388}, issn = {1365-2672}, mesh = {Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/*genetics ; Cells, Cultured ; Drug Synergism ; Gene Expression/drug effects ; Humans ; Hyphae/drug effects ; Miconazole/pharmacology ; Nystatin/pharmacology ; Plant Extracts/chemistry/*pharmacology ; Solidago/*chemistry ; }, abstract = {AIMS: Candida albicans biofilms are commonly associated with severe oral infections. We previously discovered that a crude extract from the Solidago virgaurea plant (SV extract) was a potent inhibitor of C. albicans biofilm formation. Here, we further investigate the mechanisms underlying C. albicans biofilm inhibition by the SV extract.

METHODS AND RESULTS: The SV extract was shown to inhibit laboratory and clinical C. albicans isolates adherence and hyphal transition on inert support and epithelial human cells, without affecting viability and growth of planktonic yeasts. Interestingly, RT-PCR-based experiments demonstrated that some key genes involved in adhesion and hyphal morphological switch (e.g. Hwp1p, Ece1p, Als3p) were strongly down-regulated by the SV extract. Moreover, antimicrobial synergy testing (checkerboard assay) demonstrated that antifungal effects of miconazole, nystatin or a common antiseptic mouthwash were synergistically improved when used in combination with the SV extract.

CONCLUSIONS: The SV extract prevents C. albicans biofilm formation through direct inhibition of key adherence and hyphae-associated genes.

Biofilm is considered as a key virulence factor of C. albicans infection. Our discovery of an inhibitor specifically acting on genes involved in biofilm formation paves the way for the future development of a new class of antifungal product.}, } @article {pmid31013054, year = {2019}, author = {Zhang, H and Wang, D and Zuo, X and Gao, C}, title = {UV-Responsive Multilayers with Multiple Functions for Biofilm Destruction and Tissue Regeneration.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {19}, pages = {17283-17293}, doi = {10.1021/acsami.9b04428}, pmid = {31013054}, issn = {1944-8252}, mesh = {Acrylates/chemistry ; Anti-Bacterial Agents ; Bacterial Adhesion/drug effects ; Bacterial Infections/microbiology/*prevention & control ; Biofilms/*drug effects ; Chitosan/chemistry/pharmacology ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Dimethylpolysiloxanes/chemistry ; *Guided Tissue Regeneration ; Humans ; Hydrophobic and Hydrophilic Interactions/drug effects ; Methylmethacrylates/chemistry ; Staphylococcus aureus/drug effects/pathogenicity ; Surface Properties ; Ultraviolet Rays ; }, abstract = {The increasing demands of surgical implantation highlight the significance of anti-infection of medical devices, especially antibiofilm contamination on the surface of implants. The biofilms developed by colonized microbes will largely hinder the adhesion of host cells, leading to failure in long-term applications. In this work, UV-responsive multilayers were fabricated by stepwise assembly of poly(pyrenemethyl acrylate- co-acrylic acid) (P(PA- co-AA)) micelles and chitosan on different types of substrates. Under UV irradiation, the cleavage of pyrene ester bonds in the P(PA- co-AA) molecules resulted in the increase of roughness and hydrophilicity of the multilayers. During this process, reactive oxygen species were generated in situ within 10 s, which destroyed the biofilms of Staphylococcus aureus, leading to the degradation of the bacterial matrix. The antibacterial rate was above 99.999%. The UV-irradiated multilayers allowed the attachment and proliferation of fibroblasts, endothelial cells, and smooth muscle cells, benefiting tissue integration of the implants. When poly(dimethylsiloxane) slices with the multilayers were implanted in vivo and irradiated by UV, the density of bacteria and the inflammatory level (judging from the number of neutrophils) decreased significantly. Moreover, formation of neo blood vessels surrounding the implants was observed after implantation for 7 days. These results reveal that the photoresponsive multilayers endow the implants with multifunctions of simultaneous antibiofilm and tissue integration, shedding light for applications in surface modification of implants in particular for long-term use.}, } @article {pmid31011774, year = {2019}, author = {Liu, J and Li, W and Zhu, X and Zhao, H and Lu, Y and Zhang, C and Lu, Z}, title = {Surfactin effectively inhibits Staphylococcus aureus adhesion and biofilm formation on surfaces.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {11}, pages = {4565-4574}, doi = {10.1007/s00253-019-09808-w}, pmid = {31011774}, issn = {1432-0614}, support = {31571887//National Natural Science Foundation of China/ ; CX 16-1058//Jiangsu Agricultural Science and Technology Innovation Fund/ ; }, mesh = {Bacillus subtilis/chemistry ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/*growth & development ; Biosynthetic Pathways/drug effects ; Environmental Microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Lipopeptides/isolation & purification/*metabolism ; Peptides, Cyclic/isolation & purification/*metabolism ; Polysaccharides/biosynthesis ; Quorum Sensing/drug effects ; Staphylococcus aureus/*drug effects/*physiology ; Surface Properties/drug effects ; }, abstract = {Biosurfactants are amphiphilic compounds that composed of hydrophilic and hydrophobic moieties, which possess the ability of self-organizing between phases, reducing the interfacial tension, and forming aggregates such as micelles. This spontaneous process results in significant changes in surface properties that directly influence the adherence of microorganisms. In this study, the ability of surfactin, a biosurfactant produced by Bacillus subtilis in reducing adhesion and disrupting the presence of biofilm of Staphylococcus aureus (S. aureus) on several surfaces, was investigated. Significant biofilm removal was observed on glass, polystyrene, and stainless steel surfaces. Furthermore, we explored the probable mechanism about how surfactin affected S. aureus biofilm formation. Based on our findings, surfactin had a significant effect on the polysaccharides production and especially decreased the percentage of alkali-soluble polysaccharide in biofilms. It also down-regulated the expression of icaA and icaD significantly, which are necessary for the important constituents to take shape of staphylococcal biofilm. In addition, it was found that the lipopeptide affected the quorum sensing (QS) system in S. aureus through regulating the auto inducer 2 (AI-2) activity, which has been reported to be negative for biofilm formation in S. aureus. These above properties could be applied in developing surfactin as a potential pre-coating agent on material surfaces to prevent S. aureus biofilm formation.}, } @article {pmid31010902, year = {2019}, author = {Cassin, EK and Tseng, BS}, title = {Pushing beyond the Envelope: the Potential Roles of OprF in Pseudomonas aeruginosa Biofilm Formation and Pathogenicity.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {31010902}, issn = {1098-5530}, support = {K22 AI121097/AI/NIAID NIH HHS/United States ; P20 GM103440/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Extracellular Matrix/metabolism ; Humans ; Proteomics/methods ; Pseudomonas aeruginosa/*metabolism/*pathogenicity ; Virulence/*physiology ; }, abstract = {The ability of Pseudomonas aeruginosa to form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune response. While some biofilm matrix components, such as exopolysaccharides and extracellular DNA, are relatively well characterized, the extracellular matrix proteins remain understudied. Multiple proteomic analyses of the P. aeruginosa soluble biofilm matrix and outer membrane vesicles, which are a component of the matrix, have identified OprF as an abundant matrix protein. To date, the few reports on the effects of oprF mutations on biofilm formation are conflicting, and little is known about the potential role of OprF in the biofilm matrix. The majority of OprF studies focus on the protein as a cell-associated porin. As a component of the outer membrane, OprF assumes dual conformations and is involved in solute transport, as well as cell envelope integrity. Here, we review the current literature on OprF in P. aeruginosa, discussing how the structure and function of the cell-associated and matrix-associated protein may affect biofilm formation and pathogenesis in order to inform future research on this understudied matrix protein.}, } @article {pmid31010041, year = {2019}, author = {Ostrov, I and Paz, T and Shemesh, M}, title = {Robust Biofilm-Forming Bacillus Isolates from the Dairy Environment Demonstrate an Enhanced Resistance to Cleaning-in-Place Procedures.}, journal = {Foods (Basel, Switzerland)}, volume = {8}, number = {4}, pages = {}, pmid = {31010041}, issn = {2304-8158}, support = {4210343//Israeli Dairy Board/ ; }, abstract = {One of the main strategies for maintaining the optimal hygiene level in dairy processing facilities is regular cleaning and disinfection, which is incorporated in the cleaning-in-place (CIP) regimes. However, a frail point of the CIP procedures is their variable efficiency in eliminating biofilm bacteria. In the present study, we evaluated the susceptibility of strong biofilm-forming dairy Bacillus isolates to industrial cleaning procedures using two differently designed model systems. According to our results, the dairy-associated Bacillus isolates demonstrate a higher resistance to CIP procedures, compared to the non-dairy strain of B. subtilis. Notably, the tested dairy isolates are highly persistent to different parameters of the CIP operations, including the turbulent flow of liquid (up to 1 log), as well as the cleaning and disinfecting effects of commercial detergents (up to 2.3 log). Moreover, our observations indicate an enhanced resistance of poly-γ-glutamic acid (PGA)-overproducing B. subtilis, which produces high amounts of proteinaceous extracellular matrix, to the CIP procedures (about 0.7 log, compared to the wild-type non-dairy strain of B. subtilis). We therefore suggest that the enhanced resistance to the CIP procedures by the dairy Bacillus isolates can be attributed to robust biofilm formation. In addition, this study underlines the importance of evaluating the efficiency of commercial cleaning agents in relation to strong biofilm-forming bacteria, which are relevant to industrial conditions. Consequently, we believe that the findings of this study can facilitate the assessment and refining of the industrial CIP procedures.}, } @article {pmid31007867, year = {2019}, author = {Zhang, Y and Shi, W and Song, Y and Wang, J}, title = {Metatranscriptomic analysis of an in vitro biofilm model reveals strain-specific interactions among multiple bacterial species.}, journal = {Journal of oral microbiology}, volume = {11}, number = {1}, pages = {1599670}, pmid = {31007867}, issn = {2000-2297}, abstract = {Interactions among bacteria can affect biofilm properties. Method: Here, we investigated the role of different bacteria in functional dysbiosis of an in vitro polymicrobial subgingival plaque model using both 16S rRNA and metatranscriptomic sequencing. Results: We found that high-virulence Porphyromonas gingivalis W83 had greater effects on the symbiotic species than the low-virulence P. gingivalis ATCC33277, and that Prevotella intermedia exacerbated the effects of W83. P. gingivalis significantly influenced the expression of genes related to metabolic pathways and quorum sensing of commensal oral species in a strain-specific manner. P. intermedia exerted synergistic effects with P. gingivalis W83 but antagonistic effects with strain ATCC33277, which may regulate the expression of virulence factors of P. gingivalis through the clp regulator. Discussion: The interaction networks indicated that the strongest correlation was between Fusobacterium nucleatum and Streptococcus mitis, which demonstrated their bridge and cornerstone roles in biofilm. Changes in the expression of genes relating to outer membrane proteins in F. nucleatum indicated that the addition of different bacteria can interfere with the co-adherence among F. nucleatum and other partners. Conclusion: We report here the existence of strain-specific interactions in subgingival plaque, which may enhance our understanding of periodontal micro-ecology and facilitate the development of improved plaque control strategies.}, } @article {pmid31006400, year = {2019}, author = {da Silva Carvalho, T and Rodrigues Perez, LR}, title = {Impact of biofilm production on polymyxin B susceptibility among Pseudomonas aeruginosa clinical isolates.}, journal = {Infection control and hospital epidemiology}, volume = {40}, number = {6}, pages = {739-740}, doi = {10.1017/ice.2019.85}, pmid = {31006400}, issn = {1559-6834}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Humans ; Microbial Sensitivity Tests ; Polymyxin B/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*physiology ; }, } @article {pmid31006166, year = {2019}, author = {Reynoso, E and Ferreyra, DD and Durantini, EN and Spesia, MB}, title = {Photodynamic inactivation to prevent and disrupt Staphylococcus aureus biofilm under different media conditions.}, journal = {Photodermatology, photoimmunology & photomedicine}, volume = {35}, number = {5}, pages = {322-331}, doi = {10.1111/phpp.12477}, pmid = {31006166}, issn = {1600-0781}, support = {Res D3646, Res N°4541//Consejo Nacional de Investigaciones Científicas y Técnicas/ ; PICT N°1623/12//Fondo para la Investigación Científica y Tecnológica/ ; }, mesh = {*Biofilms/drug effects/radiation effects ; Humans ; Indoles/*pharmacology ; Isoindoles ; *Light ; *Photochemotherapy ; Photosensitizing Agents/*pharmacology ; Porphyrins/*pharmacology ; Staphylococcus aureus/*physiology ; }, abstract = {OBJECTIVE: The goal of this work was to investigate the photodynamic activity of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin (TAPC) and zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine iodide (ZnPPc[4+]) as photosensitizers to inactivate Staphylococcus aureus biofilms and prevent their formations in different culture media.

METHODS: We incubated S aureus biofilms in different culture media: tryptic soy (TS), nutrient (N), Müeller Hinton (MH) broth, TS with glucose 2 and 5% (w/v) with 5 μM ZnPPc[4+] or TAPC and irradiated with visible light (350-800 nm). Photodynamic inactivation (PDI) was determined by count of colony forming units (CFU) and crystal violet method. Furthermore, we studied PDI effect on biofilm development in TS broth. Finally, we examined the effects of PDI on the structure of S aureus biofilm.

RESULTS: Greater inactivation was achieved, using TAPC or ZnPPc[4+] , when S aureus biofilm was grown in N or MH broths rather than in TS. Besides, glucose addition to the medium decreases the ability to develop biofilm and increase the photoinactivation capacity. Prevention of 3 log biofilm developments was obtained when S aureus cultures were treated with TAPC (10 μM) and 108 J/cm[2] in TS broth and the number of CFU was counted after 24 hours. Moreover, microscopy studies demonstrated modifications in biofilm architecture.

CONCLUSIONS: These results indicate that TAPC and ZnPPc[4+] may be promising photosensitizers for photodynamic inactivation of S aureus biofilms or to prevent their formation.}, } @article {pmid31004913, year = {2019}, author = {Lekbach, Y and Li, Z and Xu, D and El Abed, S and Dong, Y and Liu, D and Gu, T and Koraichi, SI and Yang, K and Wang, F}, title = {Salvia officinalis extract mitigates the microbiologically influenced corrosion of 304L stainless steel by Pseudomonas aeruginosa biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {128}, number = {}, pages = {193-203}, doi = {10.1016/j.bioelechem.2019.04.006}, pmid = {31004913}, issn = {1878-562X}, mesh = {Adsorption ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chromatography, High Pressure Liquid/methods ; *Corrosion ; Dielectric Spectroscopy ; Mass Spectrometry/methods ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Salvia officinalis/*chemistry ; Seawater ; Stainless Steel/*chemistry ; Surface Properties ; }, abstract = {The mitigation of microbiologically influenced corrosion (MIC) of 304L stainless steel (SS) against Pseudomonas aeruginosa by a Salvia officinalis extract was investigated using electrochemical and surface analysis techniques. The extract was characterized by HPLC-Q-TOF-MS and its antibiofilm property was evaluated. The data revealed the presence of well-known antimicrobial and anticorrosion compounds in the extract. The S. officinalis extract was found effective in preventing biofilm formation and inhibiting mature biofilm. Electrochemical results indicated that P. aeruginosa accelerated the MIC of 304L SS, while the extract was found to prevent the MIC with an inhibition efficiency of 97.5 ± 1.5%. This was attributed to the formation of a protective film by the adsorption of some compounds from the extract on the 304L SS surface.}, } @article {pmid31002887, year = {2019}, author = {Kunz, D and Wirth, J and Sculean, A and Eick, S}, title = {In- vitro-activity of additive application of hydrogen peroxide in antimicrobial photodynamic therapy using LED in the blue spectrum against bacteria and biofilm associated with periodontal disease.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {306-312}, doi = {10.1016/j.pdpdt.2019.04.015}, pmid = {31002887}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Hydrogen Peroxide/*pharmacology ; In Vitro Techniques ; Periodontal Diseases/*drug therapy/*microbiology ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Riboflavin/pharmacology ; }, abstract = {BACKGROUND: Although antimicrobial photodynamic therapy (aPDT) has been shown to be efficient in killing planktonic periodontopathogenic bacteria, its activity on established biofilms is very limited. The aim of the present in-vitro study was to evaluate the potential effect of hydrogen peroxide as a pretreatment for aPDT.

METHODS: aPDT consisting of riboflavin as photosensitizer and illumination by a LED lamp emitting in the blue spectrum for 30 s and 60 s (aPDT60) was combined with a pretreatment with 0.25% and 3% hydrogen peroxide. The antimicrobial activity of these treatments was determined against eight oral species (incl. Porphyromonas gingivalis and Tannerella forsythia) and against eight-species biofilms. Treatment of biofilms in an artificial pocket model included a mechanical removal of the biofilm.

RESULTS: Against planktonic bacteria, pretreatment with hydrogen peroxide increased killing of planktonic bacteria, after aPDT60 no viable bacteria were detected in 7 of 8 strains. In biofilms formed on well-plates, aPDT60 reduced bacterial counts only by 0.53 log10 cfu, whereas reduction was closed to 4 log10 or higher when 3% hydrogen peroxide was used. When biofilms were treated in the periodontal-pocket model, reduction of cfu was less than 0.5 log10 after mechanical therapy or aPDT60 only, however no bacteria were detected after mechanical biofilm removal followed by the use 3% of hydrogen peroxide and aPDT60.

CONCLUSIONS: aPDT using riboflavin and blue LED light applied after mechanical removal of biofilm and adjunctive 3% hydrogen peroxide solution appears to represent an alternative for antimicrobial periodontal therapy.}, } @article {pmid31002106, year = {2019}, author = {Yu, L and Li, W and Qi, K and Wang, S and Chen, X and Ni, J and Deng, R and Shang, F and Xue, T}, title = {McbR is involved in biofilm formation and H2O2 stress response in avian pathogenic Escherichia coli X40.}, journal = {Poultry science}, volume = {98}, number = {9}, pages = {4094-4103}, doi = {10.3382/ps/pez205}, pmid = {31002106}, issn = {1525-3171}, mesh = {Animals ; *Biofilms ; Bird Diseases/microbiology ; Escherichia coli/genetics/*physiology ; Escherichia coli Infections/microbiology/veterinary ; Escherichia coli Proteins/*genetics/metabolism ; Hydrogen Peroxide/*adverse effects ; Stress, Physiological ; Transcription Factors/*genetics/metabolism ; }, abstract = {Avian pathogenic Escherichia coli (APEC) causes a variety of extraintestinal diseases known as colibacillosis and is responsible for significant economic losses in the poultry industry worldwide. Biofilm formation results in increased morbidity and persistent infections, and is the main reason for the difficult treatment of colibacillosis with antimicrobial agents. It is reported that the transcriptional regulator McbR regulates biofilm formation and mucoidy by repressing the expression of the periplasmic protein YbiM, and activates the transcription of the yciGFE operon by binding to the yciG promoter in E. coli K-12. However, whether McbR regulates biofilm formation and H2O2 stress response in APEC has been not reported. The present study showed that, in the clinical isolate APECX40, the deletion of mcbR increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, fliC, wcaF, and fimA. In addition, the deletion of mcbR decreased H2O2 stress response by downregulating the transcript levels of the stress-associated genes yciF and yciE. The electrophoretic mobility shift assays confirmed that McbR directly binds to the promoter regions of yciG and yciF. This study may provide new clues to understanding gene regulation in APEC.}, } @article {pmid31001972, year = {2019}, author = {Wilt, IK and Hari, TPA and Wuest, WM}, title = {Hijacking the Bacterial Circuitry of Biofilm Processes via Chemical "Hot-Wiring": An Under-explored Avenue for Therapeutic Development.}, journal = {ACS infectious diseases}, volume = {5}, number = {6}, pages = {789-795}, pmid = {31001972}, issn = {2373-8227}, support = {R35 GM119426/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects ; Bacterial Infections/drug therapy ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/drug effects/*growth & development ; Drug Development/methods ; Humans ; Nucleotides, Cyclic/metabolism ; Polysaccharides, Bacterial/chemistry ; Quorum Sensing/drug effects ; Signal Transduction/drug effects ; }, abstract = {Biofilm-associated infections are linked to chronic and recurring illnesses. These infections are often not susceptible to current antibiotic treatments because of the protective exocellular matrix and subpopulations of dormant or "persister" cells. Targeting bacterial circuitry involved in biofilm formation, including two-component systems, quorum sensing, polysaccharide structural integrity, and cyclic nucleotide signaling pathways, has the potential to expand the existing arsenal of therapeutics, thus catalyzing a second golden age of antibiotic development.}, } @article {pmid31001942, year = {2019}, author = {Tu, C and Wang, Y and Yi, L and Wang, Y and Liu, B and Gong, S}, title = {[Roles of signaling molecules in biofilm formation].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {35}, number = {4}, pages = {558-566}, doi = {10.13345/j.cjb.180326}, pmid = {31001942}, issn = {1872-2075}, mesh = {Bacterial Proteins ; *Biofilms ; Cyclic GMP ; Gene Expression Regulation, Bacterial ; Protein Binding ; Quorum Sensing ; }, abstract = {Bacterial biofilm refers to a tunicate-like biological group composed of polysaccharide, protein and nucleic acid secreted by bacteria on the surface of the mucous membrane or biological material. The biofilm formation is a major cause of chronic infections. Bacteria could produce some secondary metabolites during the growth and reproduction. Some of them act as signaling molecules allowing bacteria to communicate and regulate many important physiological behaviors at multiple-cell level, such as bioluminescence, biofilm formation, motility and lifestyles. Usually, these signal molecules play an important role in the formation of bacterial biofilm. We review here the effects of related signal molecules of Quorum Sensing, cyclic diguanylate, Two-Component Systems and sRNA on the biofilm formation. Focusing on these regulation mechanism of signal molecules in the process of biofilm formation is necessary for the prevention and treatment of some chronic diseases.}, } @article {pmid31001488, year = {2019}, author = {Moussouni, M and Nogaret, P and Garai, P and Ize, B and Vivès, E and Blanc-Potard, AB}, title = {Activity of a Synthetic Peptide Targeting MgtC on Pseudomonas aeruginosa Intramacrophage Survival and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {84}, pmid = {31001488}, issn = {2235-2988}, mesh = {Biofilms/*drug effects/growth & development ; Cation Transport Proteins/*antagonists & inhibitors ; Enzyme Inhibitors/isolation & purification/*pharmacology ; Macrophages/*microbiology ; Microbial Viability/*drug effects ; Peptides/genetics/isolation & purification/*pharmacology ; Pseudomonas aeruginosa/*drug effects/growth & development ; }, abstract = {Antivirulence strategies aim to target pathogenicity factors while bypassing the pressure on the bacterium to develop resistance. The MgtC membrane protein has been proposed as an attractive target that is involved in the ability of several major bacterial pathogens, including Pseudomonas aeruginosa, to survive inside macrophages. In liquid culture, P. aeruginosa MgtC acts negatively on biofilm formation. However, a putative link between these two functions of MgtC in P. aeruginosa has not been experimentally addressed. In the present study, we first investigated the contribution of exopolysaccharides (EPS) in the intramacrophage survival defect and biofilm increase of mgtC mutant. Within infected macrophages, expression of EPS genes psl and alg was increased in a P. aeruginosa mgtC mutant strain comparatively to wild-type strain. However, the intramacrophage survival defect of mgtC mutant was not rescued upon introduction of psl or alg mutation, suggesting that MgtC intramacrophage role is unrelated to EPS production, whereas the increased biofilm formation of mgtC mutant was partially suppressed by introduction of psl mutation. We aimed to develop an antivirulence strategy targeting MgtC, by taking advantage of a natural antagonistic peptide, MgtR. Heterologous expression of mgtR in P. aeruginosa PAO1 was shown to reduce its ability to survive within macrophages. We investigated for the first time the biological effect of a synthetic MgtR peptide on P. aeruginosa. Exogenously added synthetic MgtR peptide lowered the intramacrophage survival of wild-type P. aeruginosa PAO1, thus mimicking the phenotype of an mgtC mutant as well as the effect of endogenously produced MgtR peptide. In correlation with this finding, addition of MgtR peptide to bacterial culture strongly reduced MgtC protein level, without reducing bacterial growth or viability, thus differing from classical antimicrobial peptides. On the other hand, the addition of exogenous MgtR peptide did not affect significantly biofilm formation, indicating an action toward EPS-independent phenotype rather than EPS-related phenotype. Cumulatively, our results show an antivirulence action of synthetic MgtR peptide, which may be more potent against acute infection, and provide a proof of concept for further exploitation of anti-Pseudomonas strategies.}, } @article {pmid31001485, year = {2019}, author = {Fleitas Martínez, O and Cardoso, MH and Ribeiro, SM and Franco, OL}, title = {Recent Advances in Anti-virulence Therapeutic Strategies With a Focus on Dismantling Bacterial Membrane Microdomains, Toxin Neutralization, Quorum-Sensing Interference and Biofilm Inhibition.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {74}, pmid = {31001485}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacteria/*drug effects/pathogenicity ; Biofilms/*drug effects ; Drug Discovery/*trends ; Membrane Microdomains/*drug effects ; Quorum Sensing/*drug effects ; Virulence/*drug effects ; Virulence Factors/antagonists & inhibitors ; }, abstract = {Antimicrobial resistance constitutes one of the major challenges facing humanity in the Twenty-First century. The spread of resistant pathogens has been such that the possibility of returning to a pre-antibiotic era is real. In this scenario, innovative therapeutic strategies must be employed to restrict resistance. Among the innovative proposed strategies, anti-virulence therapy has been envisioned as a promising alternative for effective control of the emergence and spread of resistant pathogens. This review presents some of the anti-virulence strategies that are currently being developed, it will cover strategies focused on quench pathogen quorum sensing (QS) systems, disassemble of bacterial functional membrane microdomains (FMMs), disruption of biofilm formation and bacterial toxin neutralization.}, } @article {pmid31001340, year = {2019}, author = {Kallick, E and Nistico, L and Longwell, M and Byers, B and Cartieri, F and Kreft, R and Edington, H}, title = {Resistance of Synthetic and Biologic Surgical Meshes to Methicillin-Resistant Staphylococcus aureus Biofilm: An In Vitro Investigation.}, journal = {International journal of biomaterials}, volume = {2019}, number = {}, pages = {1063643}, pmid = {31001340}, issn = {1687-8787}, abstract = {Surgical meshes have become the standard procedure for a variety of surgical applications with 20 million meshes being implanted each year. The popularity of mesh usage among surgeons is backed by the multiple studies that support its functionality as a tool for improving surgical outcomes. However, their use has also been associated with infectious surgical complications and many surgeons have turned to biologic meshes. While there have been several studies investigating synthetic meshes, there is limited data comparing synthetic and biologic meshes in vitro in an infection model. This study evaluates the in vitro susceptibility of both synthetic and biologic meshes to single-species methicillin-resistant Staphylococcus aureus (MRSA) biofilms. This research compares biofilm biomass, average thickness, and coverage between the three meshes through florescent in situ hybridization (FISH), confocal scanning microscopy (CSLM), and image analysis. We also report the varying levels of planktonic and attached bacteria through sonication and cfu counts. While the data illustrates increased biofilm formation on biologic mesh in vitro, the study must further be investigated in vivo to confirm the study observations.}, } @article {pmid31001240, year = {2019}, author = {Reichhardt, C and Parsek, MR}, title = {Confocal Laser Scanning Microscopy for Analysis of Pseudomonas aeruginosa Biofilm Architecture and Matrix Localization.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {677}, pmid = {31001240}, issn = {1664-302X}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; R01 AI143916/AI/NIAID NIH HHS/United States ; }, abstract = {Most microbes can produce surface-associated or suspended aggregates called biofilms, which are encased within a biopolymer-rich matrix. The biofilm matrix provides structural integrity to the aggregates and shields the resident cells against environmental stressors, including antibiotic treatment. Microscopy permits examination of biofilm structure in relation to the spatial localization of important biofilm matrix components. This review highlights microscopic approaches to investigate bacterial biofilm assembly, matrix composition, and localization using Pseudomonas aeruginosa as a model organism. Initial microscopic investigations provided information about the role key matrix components play in elaborating biofilm aggregate structures. Additionally, staining of matrix components using specific labels revealed distinct positioning of matrix components within the aggregates relative to the resident cells. In some cases, it was found that individual matrix components co-localize within aggregates. The methodologies for studying the biofilm matrix are continuing to develop as our studies reveal novel aspects of its composition and function. We additionally describe some outstanding questions and how microscopy might be used to identify the functional aspects of biofilm matrix components.}, } @article {pmid31000791, year = {2019}, author = {Kim, SG and Jun, JW and Giri, SS and Yun, S and Kim, HJ and Kim, SW and Kang, JW and Han, SJ and Jeong, D and Park, SC}, title = {Isolation and characterisation of pVa-21, a giant bacteriophage with anti-biofilm potential against Vibrio alginolyticus.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {6284}, pmid = {31000791}, issn = {2045-2322}, mesh = {Bacteriophages/*genetics/*isolation & purification ; Biofilms/growth & development ; Genome, Viral/genetics ; Genomics ; Host Specificity/genetics ; Humans ; Phylogeny ; Vibrio Infections/*genetics/therapy/virology ; Vibrio alginolyticus/*genetics/isolation & purification ; }, abstract = {There is an increasing emergence of antibiotic-resistant Vibrio alginolyticus, a zoonotic pathogen that causes mass mortality in aquatic animals and infects humans; therefore, there is a demand for alternatives to antibiotics for the treatment and prevention of infections caused by this pathogen. One possibility is through the exploitation of bacteriophages. In the present study, the novel bacteriophage pVa-21 was classified as Myoviridae and characterised as a candidate biocontrol agent against V. alginolyticus. Its morphology, host range and infectivity, growth characteristics, planktonic or biofilm lytic activity, stability under various conditions, and genome were investigated. Its latent period and burst size were estimated to be approximately 70 min and 58 plaque-forming units/cell, respectively. In addition, phage pVa-21 can inhibit bacterial growth in both the planktonic and biofilm states. Furthermore, phylogenetic and genome analysis revealed that the phage is closely related to the giant phiKZ-like phages and can be classified as a new member of the phiKZ-like bacteriophages that infect bacteria belonging to the family Vibrionaceae.}, } @article {pmid31000317, year = {2019}, author = {Iliescu Nelea, M and Paek, L and Dao, L and Rouchet, N and Efanov, JI and Édouard, C and Danino, MA}, title = {In-situ characterization of the bacterial biofilm associated with Xeroform™ and Kaltostat™ dressings and evaluation of their effectiveness on thin skin engraftment donor sites in burn patients.}, journal = {Burns : journal of the International Society for Burn Injuries}, volume = {45}, number = {5}, pages = {1122-1130}, doi = {10.1016/j.burns.2019.02.024}, pmid = {31000317}, issn = {1879-1409}, mesh = {Adult ; Aged ; *Alginates ; Bacteria/*ultrastructure ; Bandages/*microbiology ; *Biofilms ; Female ; Humans ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; *Phenols ; Skin Transplantation ; Transplant Donor Site/*microbiology ; Transplantation, Autologous ; Young Adult ; }, abstract = {Biofilm forms when bacteria surrounded by an extracellular matrix aggregate on a surface. It can develop on many surfaces, including wound dressings; this can be particularly nefarious for burn patients undergoing skin grafting (autograft) for burn wound coverage as they often suffer from compromised immune system function. Autograft donor sites are particularly vulnerable to biofilm formation; as such, timely healing of these sites is essential. Our aim was to apply scanning electron microscopy to compare the efficacy of two types of wound dressings in preventing the formation of bacterial biofilm on burn patient skin graft donor sites. One dressing contained bismuth tribromophenate at a concentration of 3% which confers it bacteriostatic properties (Xeroform™). The other was an absorptive alginate calcium sodium dressing (Kaltostat™). Samples of each wound dressing, which were in contact with the skin graft donor site, were prepared for analysis under the scanning electron microscope (SEM) using an original method developed by our research group that aims to maintain the integrity of the biofilm microstructure. Samples prepared by this method were then analyzed using SEM, which allowed the characterization of biofilm and the evaluation of bacterial density on the studied dressing samples. To this day, this imaging technique has been rarely employed for dressing analysis and this is the first time that it is employed for in situ biofilm visualization for this particular application.}, } @article {pmid30999180, year = {2019}, author = {Xia, S and Xu, X and Zhou, L}, title = {Insights into selenate removal mechanism of hydrogen-based membrane biofilm reactor for nitrate-polluted groundwater treatment based on anaerobic biofilm analysis.}, journal = {Ecotoxicology and environmental safety}, volume = {178}, number = {}, pages = {123-129}, doi = {10.1016/j.ecoenv.2019.04.005}, pmid = {30999180}, issn = {1090-2414}, mesh = {Anaerobiosis ; Betaproteobacteria/growth & development ; Biofilms/drug effects/*growth & development ; Bioreactors/*microbiology ; Groundwater/*chemistry ; Hydrogen/*chemistry ; Membranes, Artificial ; Models, Theoretical ; Nitrates/*analysis ; Selenic Acid/*analysis ; Water Pollutants, Chemical/*analysis ; Water Purification/*methods ; }, abstract = {The selenate removal mechanism of hydrogen-based membrane biofilm reactor (MBfR) for nitrate-polluted groundwater treatment was studied based on anaerobic biofilm analysis. A laboratory-scale MBfR was operated for over 60 days with electron balance, structural analysis, and bacterial community identification. Results showed that anaerobic biofilm had an excellent removal of both selenate (95%) and nitrate (100%). Reduction of Selenate → Selenite → Se[0] with hydrogen was the main pathway of anaerobic biofilm for selenate removal with amorphous Se[0] precipitate accumulating in the biofilm. The element selenium was observed to be evenly distributed along the cross-sectional thin biofilm. A part of selenate (3%) was also reduced into methyl-selenide by heterotrophic bacteria. Additionally, Hydrogenophaga bacteria of β-Proteobacteria, capable of both nitrate and selenate removal, worked as the dominant species (over 85%) in the biofilm and contributed to the stable removal of both nitrate and selenate. With the selenate input, bacteria with a capacity for both selenate and nitrate removal were also developed in the anaerobic biofilm community.}, } @article {pmid30998780, year = {2019}, author = {Waseem, M and Williams, JQL and Thangavel, A and Still, PC and Ymele-Leki, P}, title = {A structural analog of ralfuranones and flavipesins promotes biofilm formation by Vibrio cholerae.}, journal = {PloS one}, volume = {14}, number = {4}, pages = {e0215273}, pmid = {30998780}, issn = {1932-6203}, support = {R25 GM062252/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms/drug effects/growth & development ; Lactones/*pharmacology ; Pyruvic Acid/metabolism ; Vibrio cholerae/*physiology ; }, abstract = {Phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) is a highly conserved, multistep chemical process which uses phosphate transfer to regulate the intake and use of sugars and other carbohydrates by bacteria. In addition to controlling sugar uptake, the PTS regulates several bacterial cellular functions such as chemotaxis, glycogen metabolism, catabolite repression and biofilm formation. Previous studies have shown that the phosphoenolpyruvate (PEP) to pyruvate ratio is a critical determinant of PTS functions. This study shows that 2-oxo-4-phenyl-2,5-dihydro-3-furancarbonitrile (MW01), a compound with structural similarity to known natural products, induces Vibrio cholerae to grow preferentially in the biofilm mode in a mechanism that involves interaction with pyruvate. Spectrophotometric assays were used to monitor bacterial growth kinetics in microtiter plates and quantitatively evaluate biofilm formation in borosilicate glass tubes. Evidence of MW01 and pyruvate interactions was determined by nuclear magnetic resonance spectroscopy. Given the established connection between PTS activity and biofilm formation, this study also highlights the potential impact that small-molecule modulators of the PTS may have in the development of innovative approaches to manage desired and undesired microbial cultures in clinical, industrial and environmental settings.}, } @article {pmid30998699, year = {2019}, author = {Goc, A and Sumera, W and Niedzwiecki, A and Rath, M}, title = {10-undecynoic acid is a new anti-adherent agent killing biofilm of oral Streptococcus spp.}, journal = {PloS one}, volume = {14}, number = {4}, pages = {e0214763}, pmid = {30998699}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Fatty Acids, Unsaturated/*pharmacology ; Microbial Sensitivity Tests ; Streptococcus/drug effects/*physiology ; }, abstract = {In the search for novel agents against oral pathogens in their planktonic and biofilm form, we have focused our attention on 10-undecynoic acid as the representative of the acetylenic fatty acids. Using macro-broth susceptibility testing method we first established MIC value. Next, the MBC value was determined from a broth dilution minimum inhibitory concentration test by sub-culturing it to BHI agar plates that did not contain the test agent. Anti-biofilm efficacy was tested in 96-well plates coated with saliva using BHI broth supplemented with 1% sucrose as a standard approach. Based on obtained results, MIC value for 10-undecynoic acid was established to be 2.5 mg/ml and the MBC value to be 5 mg/ml. The MBIC90 showed to be 2.5 mg/ml, however completed inhibition of biofilm formation was achieved at 5.0 mg/ml. MBBC concentration revealed to be the same as MBC value, causing approximately 30% reduction at the same time in biomass of pre-existing biofilm, whereas application of 7.0 mg/ml of 10-undecynoic acid crossed the 50% eradication mark. Strong anti-adherent effect was observed upon 10-undecynoic acid application at sub-MBC concentrations as well, complemented with suppression of acidogenicity and aciduricity. Thus, we concluded that 10-undecynoic acid might play an important role in the development of alternative or adjunctive antibacterial and anti-biofilm preventive and/or therapeutic approaches.}, } @article {pmid30998111, year = {2019}, author = {Nwabor, OF and Vongkamjan, K and Voravuthikunchai, SP}, title = {Antioxidant Properties and Antibacterial Effects of Eucalyptus camaldulensis Ethanolic Leaf Extract on Biofilm Formation, Motility, Hemolysin Production, and Cell Membrane of the Foodborne Pathogen Listeria monocytogenes.}, journal = {Foodborne pathogens and disease}, volume = {16}, number = {8}, pages = {581-589}, doi = {10.1089/fpd.2019.2620}, pmid = {30998111}, issn = {1556-7125}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects ; *Eucalyptus ; *Food Microbiology ; Hemolysin Proteins/biosynthesis/drug effects ; Humans ; Listeria monocytogenes/*drug effects/physiology ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plant Leaves ; }, abstract = {Consumer concerns toward chemical preservatives have resulted in increased search for healthy green alternative. In this study, the antioxidant activity and antibacterial effects of Eucalyptus camaldulensis ethanolic leaf extract against Listeria monocytogenes, a serious foodborne pathogen, was evaluated. Total phenolic and flavonoid contents of the extract were 11.10 mg garlic acid equivalent/mg extract and 15.05 mg quercetin equivalent/mg extract, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration of the extract was 64-128 μg/mL and 256-512 μg/mL, respectively. Time-kill assay revealed growth inhibitory effects after 4-h treatment of the bacteria with the extract. A reduction of ≈2-3 log colony-forming units per milliliter was observed against the tested food and environmental isolates after challenging the pathogens with the extract at MIC for 6 h. Sub-MICs of the extract significantly inhibited motility and listeriolysin O production up to 80%, with 60% inhibition of biofilm formation (p < 0.05). Antioxidant assay revealed free radical scavenging activity with 50% inhibitory concentration (IC50) of 57.07 μg/mL for 2,2-diphenyl-1-picrylhydrazyl and 29.01 μg/mL for ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] assay. Ferric reducing antioxidant power assay further showed a total antioxidant power equivalent to 92.93 μM ascorbic acid equivalent/mg extract. As the extract exhibited profound antilisterial activity and good radical scavenging ability, it might serve as a potential alternative source of biopreservative agent against L. monocytogenes.}, } @article {pmid30996828, year = {2019}, author = {Bahador, N and Shoja, S and Faridi, F and Dozandeh-Mobarrez, B and Qeshmi, FI and Javadpour, S and Mokhtary, S}, title = {Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas.}, journal = {Iranian journal of microbiology}, volume = {11}, number = {1}, pages = {25-30}, pmid = {30996828}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa.

MATERIALS AND METHODS: In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimicrobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed.

RESULTS: Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%).

CONCLUSION: The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particularly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.}, } @article {pmid30996209, year = {2019}, author = {Minami, M and Takase, H and Nakamura, M and Makino, T}, title = {Methanol extract of Lonicera caerulea var. emphyllocalyx fruit has antibacterial and anti-biofilm activity against Streptococcus pyogenes in vitro.}, journal = {Bioscience trends}, volume = {13}, number = {2}, pages = {145-151}, doi = {10.5582/bst.2019.01005}, pmid = {30996209}, issn = {1881-7823}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fruit/*chemistry ; Hydrophobic and Hydrophilic Interactions ; Lonicera/*chemistry ; Methanol/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Plant Stems/chemistry ; Streptococcus pyogenes/cytology/drug effects/growth & development/*physiology ; }, abstract = {Streptococcus pyogenes causes several infectious diseases such as tonsillitis, cellulitis, and streptococcal toxic shock syndrome. As antibiotics are used for the general treatment of S. pyogenes infection, cases of treatment failure due to drug-resistant bacteria have increased. Lonicera caerulea var. emphyllocalyx (LCE) has been used as a folk medicine in northern Japan (Hokkaido). In this study, we investigated the antibacterial effect of methanol extracts of the fruit, stem, and leaf of LCE (LCEEs) against S. pyogenes using disk diffusion assay. As LCEE (fruit) had the strongest antibacterial activity among the three LCEEs, we focused on functional analysis of antibacterial effects of LCEE (fruit). LCEE (fruit) suppressed the growth of S. pyogenes in a dose-dependent manner. Morphological analysis by transmission electron microscopy demonstrated that LCEE (fruit) damaged the shape of S. pyogenes. Microplate and confocal laser microscopy analysis showed that biofilm formation was also suppressed by LCEE (fruit) in a dose-dependent manner. To further evaluate the surface structure of these biofilms, we performed hydrophobic analysis, which demonstrated that LCEE (fruit) reduced the hydrophobicity of the bacterial surface structure. Our data demonstrated that LCEE (fruit) had anti-bacterial and anti-biofilm effects on S. pyogenes in vitro, suggesting that the direct anti-bacterial effects of the LCEE (fruit) may be useful for treatment of local S. pyogenes infection.}, } @article {pmid30995873, year = {2019}, author = {Osman, K and Orabi, A and Elbehiry, A and Hanafy, MH and Ali, AM}, title = {Pseudomonas species isolated from camel meat: quorum sensing-dependent virulence, biofilm formation and antibiotic resistance.}, journal = {Future microbiology}, volume = {14}, number = {}, pages = {609-622}, doi = {10.2217/fmb-2018-0293}, pmid = {30995873}, issn = {1746-0921}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins ; Biofilms/*growth & development ; Camelus ; Chlorocebus aethiops ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Multiple, Bacterial/drug effects/*genetics ; Egypt/epidemiology ; Endopeptidases ; Food Microbiology ; Genes, Bacterial/genetics ; Meat/*microbiology ; Pancreatic Elastase ; Polymerase Chain Reaction/methods ; Pseudomonas/classification/*drug effects/*genetics/isolation & purification ; Pseudomonas Infections/epidemiology/*microbiology/*veterinary ; Pseudomonas aeruginosa/drug effects/isolation & purification ; Pseudomonas fluorescens/drug effects/isolation & purification ; Pyocyanine ; Quorum Sensing/*genetics ; Vero Cells ; Virulence/genetics ; Virulence Factors/*genetics ; beta-Lactamases/genetics ; }, abstract = {Aim: This research pioneers the process of obtaining information concerning the distribution and existence of seven ESBL genes linked to Pseudomonas, three virulence and five quorum sensing separated from 100 camel meat samples using PCR. Materials & methods: The Vitek system was used to identify Pseudomonas species. Phenotypic antibiotic resistance of 16 antibiotics was tested by disc diffusion. Quantification of pyocyanin, elastase, alkaline protease, biofilm and Vero cell cytotoxicity was also implemented. Results: The total number of Pseudomonas species isolated from camel meat was 10/100 identified as Pseudomonas aeruginosa 8/10, Pseudomonas fluorescens 2/10. The isolates were multidrug resistant and were resistant to four to eight antibiotics representing four to six classes. The 15 genes exhibited a huge diversity in their association. Conclusion: The results indicated that camel meat is an unpropitious hotbed for Pseudomonas species of clinical significance.}, } @article {pmid30995575, year = {2019}, author = {Wu, M and Luo, JH and Hu, S and Yuan, Z and Guo, J}, title = {Perchlorate bio-reduction in a methane-based membrane biofilm reactor in the presence and absence of oxygen.}, journal = {Water research}, volume = {157}, number = {}, pages = {572-578}, doi = {10.1016/j.watres.2019.04.008}, pmid = {30995575}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors ; Methane ; Oxidation-Reduction ; Oxygen ; *Perchlorates ; }, abstract = {Perchlorate has been widely detected in various water environments and could cause serious health problems. Methane has been proposed as a promising electron donor to remove perchlorate from contaminated water, yet it is unclear whether and how microbial methane oxidation couples with perchlorate reduction, in particular under anoxic conditions. Here, the feasibility and performance of perchlorate reduction driven by methane in the presence and absence of oxygen were investigated and compared in a lab-scale methane-based membrane biofilm reactor. Long-term operational performance suggested that perchlorate was reduced to chloride, with 4 mg Cl/L/d of perchlorate removal rate under anoxic conditions. Differently, perchlorate removal rate increased to 16 mg Cl/L/d, and volatile fatty acids (VFAs) were produced from methane partial oxidation when a limited oxygen (10 mg/L/d) was externally supplied. Regardless of oxygen conditions, microbial perchlorate reduction driven by methane might be mediated through synergistic interactions by a microbial consortium, but with different key microbial members under both oxygen regimes. Under anoxic conditions, aerobic methanotrophs (likely Methylocystaceae and Methylococcaceae) might micro-aerobically oxidize methane by utilizing internal oxygen from microbial perchlorate reduction, which might be mediated by Rhodocyclaceae. In contrast, under oxygen-limiting conditions, methanogens (e.g., Methanosarcina) and fermenters (e.g., Veillonellaceae) likely jointly converted methane into VFAs, then dissimilatory perchlorate-reducing bacteria (e.g., Rhodocyclaceae) utilized the produced VFAs to reduce perchlorate to chloride. Our findings provide evidence to link methane oxidation with perchlorate reduction under both oxygen regimes, which could be facilitated to design a process to remove perchlorate from groundwater.}, } @article {pmid30995521, year = {2019}, author = {Katalinić, I and Budimir, A and Bošnjak, Z and Jakovljević, S and Anić, I}, title = {The photo-activated and photo-thermal effect of the 445/970 nm diode laser on the mixed biofilm inside root canals of human teeth in vitro: A pilot study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {277-283}, doi = {10.1016/j.pdpdt.2019.04.014}, pmid = {30995521}, issn = {1873-1597}, mesh = {Biofilms/*radiation effects ; Candida albicans/radiation effects ; Dental Pulp Cavity/*microbiology ; Disinfection/methods ; Enterococcus faecalis/radiation effects ; Humans ; In Vitro Techniques ; *Lasers, Semiconductor ; Pilot Projects ; Root Canal Irrigants/pharmacology ; Root Canal Preparation ; Sodium Hypochlorite/pharmacology ; Staphylococcus aureus/radiation effects ; }, abstract = {AIMS: 1) Evaluation of the photo-thermal (PT) and photo-activated (PAD) antibacterial effect of the 445/970 nm diode laser on E. faecalis, S. aureus and C. albicans mixed biofilms grown together inside root canals of human teeth. 2) Defining a potentially efficient clinical protocol for safe and predictable usage in endodontic procedures.

METHODOLOGY: The root canals of 100 extracted human teeth with single straight canals were prepared with ProTaper NEXT files, sterilized, contaminated with a combination of three cultures (E. faecalis, S. aureus, C. albicans) and incubated for 15 days. The samples were randomly distributed into three groups (n = 20) and treated as follows: Group 1 (G1) - the 445 nm photo-thermal (PT) effect, Group 2 (G2) - a combination of the 445 nm and 970 nm PT effect, Group 3 (G3) - the 445 nm photo-activated (PAD) effect with 0.1% riboflavin, Group 4 (G4) - a combination of 3% sodium hypochlorite (NaOCl) and the 445 nm PAD effect. Four samples were used as positive control (non-treated) and four as a negative control. 12 aditional samples were used as a control for the G4 (3% NaOCl rinse without the laser). The number of viable microbes in each canal was determined by the colony forming unit (CFU) count.

RESULTS: A statistically significant reduction in the microbial population after all treatments was observed (P < 0.001). Groups 2 and 3 showed similar results, both better than Group 1. Group 4 produced the best results.

CONCLUSIONS: The 445 nm PAD protocol has a stronger antimicrobial effect than the 445 nm PT protocol. Prolonged exposure time to laser light and a combination of wavelengths (445/970 PT protocol) helps in the reduction of microbes. C. albicans appears to be more sensitive to laser irradiation than the other bacteria tested in this study. Following current results, tested laser protocols could be recommended for clinical usage but only as an adjunct to "classic" NaOCl rinse since alone they are not able to completely eradicate all microorganisms.}, } @article {pmid30995049, year = {2019}, author = {Blakeman, JT and Morales-García, AL and Mukherjee, J and Gori, K and Hayward, AS and Lant, NJ and Geoghegan, M}, title = {Extracellular DNA Provides Structural Integrity to a Micrococcus luteus Biofilm.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {35}, number = {19}, pages = {6468-6475}, doi = {10.1021/acs.langmuir.9b00297}, pmid = {30995049}, issn = {1520-5827}, mesh = {Bacterial Adhesion ; *Biofilms ; DNA, Bacterial/*metabolism ; Deoxyribonuclease I/metabolism ; Extracellular Space/*metabolism ; Hydrolysis ; Micrococcus luteus/*cytology/*physiology ; Polysaccharides, Bacterial/metabolism ; }, abstract = {Force spectroscopy was used to show that extracellular DNA (eDNA) has a pre-eminent structural role in a biofilm. The adhesive behavior of extracellular polymeric substances to poly(ethylene terephthalate), a model hydrophobic surface, was measured in response to their degradation by hydrolytic enzymes known for their biofilm dispersion potential: DNaseI, protease, cellulase, and mannanase. Only treatment with DNaseI significantly decreased the adhesive force of the model bacterium Micrococcus luteus with the surface, and furthermore this treatment almost completely eliminated any components of the biofilm maintaining the adhesion, establishing a key structural role for eDNA.}, } @article {pmid30994755, year = {2019}, author = {Curvelo, JAR and Moraes, DC and Anjos, CAD and Portela, MB and Soares, RMA}, title = {Histatin 5 and human lactoferrin inhibit biofilm formation of a fluconazole resistant Candida albicans clinical isolate.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {91}, number = {1}, pages = {e20180045}, doi = {10.1590/0001-3765201920180045}, pmid = {30994755}, issn = {1678-2690}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/isolation & purification ; Colony Count, Microbial ; Drug Resistance, Fungal/*drug effects ; Fluconazole/*pharmacology ; Histatins/*pharmacology ; Humans ; Lactoferrin/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Reference Values ; Reproducibility of Results ; }, abstract = {Candida albicans is the most important fungal pathogen that causes infections in humans. Biofilms are hard-to-treat structures due to their high antifungal resistance. Saliva is a fluid that contains antimicrobial substances acting as the first-line of defense against pathogens, and its immune components may be potential tools for the discovery of new treatments against candidiasis. To evaluate the activity of histatin 5 and human lactoferrin against biofilm formation. A fluconazole-resistant Candida albicans clinical isolate was used as the model microorganism. Morphogenesis was evaluated by differential counting. Biofilm quantification was performed by XTT reduction assay. Thickness and topography of biofilms were assessed through confocal laser scanning microscopy (CLSM). Histatin 5 inhibited yeast-to-hyphae transition in a dose-dependent manner, while the effect of human lactoferrin on this process was inversely proportional to its concentration. Both compounds were able to significantly inhibit biofilm metabolic activity. Histatin 5 reduced biofilm thickness. Histatin 5 and human lactoferrin exhibited in vitro cytotoxicity against a fluconazole-resistant Candida albicans biofilm, which points to the potential application of these compounds in the treatment of biofilms formed by this fungus, especially in resistant infections.}, } @article {pmid30993384, year = {2019}, author = {RedCorn, RM and Hillman, ET and Solomon, KV and Engelberth, AS}, title = {Xanthobacter-dominated biofilm as a novel source for high-value rhamnose.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {11}, pages = {4525-4538}, doi = {10.1007/s00253-019-09765-4}, pmid = {30993384}, issn = {1432-0614}, support = {FP-91780201-0//EPA STAR/ ; }, mesh = {Biofilms/*growth & development ; Carbon/metabolism ; Cluster Analysis ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Fatty Acids/metabolism ; Glucose/metabolism ; *Microbial Consortia ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Rhamnose/isolation & purification/*metabolism ; Sequence Analysis, DNA ; Sewage/microbiology ; Xanthobacter/*growth & development/*metabolism ; }, abstract = {Rhamnose is a high-value carbohydrate used in flavorings, aromatics, and pharmaceuticals. Current demand for rhamnose is filled through plant-based sources; however, microbially originated rhamnolipids have been proposed as an alternative source. A mixed microbial biofilm, cultured from a wastewater sludge, was found to comprise > 8 dry weight% rhamnose when provided volatile fatty acids as carbon source, and 24 dry weight% when given glucose. The latter rhamnose concentration is a fourfold higher production mass than the current plant-based origin and is competitive with yields from pure microbial cultures. The biofilm was characterized based on total carbohydrate production at varying nutrient levels, individual carbohydrate monomer production from varying organic acid substrates, and microbial community composition-based on 16s rRNA. Biofilm carbohydrate production was maximized at a C:N ratio of 28 (mol:mol). The production of rhamnose varied significantly based on carbon substrate; glucose had the greatest yield of rhamnose, followed by propionic acid, lactic acid, acetic acid, valeric acid, and butyric acid. Microbial community analysis indicated an abundance of organisms within the Xanthobacter genus, which is known to produce rhamnose as zeaxanthin rhamnoside. Rhamnose production was heavily correlated with ribose production (R[2] = 0.96). Results suggest that mixed microbial biofilms could be a competitive source of monomeric rhamnose that may be produced from mixed organic waste streams of variable composition via volatile fatty acids and glucose.}, } @article {pmid30991917, year = {2019}, author = {Rumyantceva, V and Rumyantceva, V and Koshel, E and Vinogradov, V}, title = {Biocide-conjugated magnetite nanoparticles as an advanced platform for biofilm treatment.}, journal = {Therapeutic delivery}, volume = {10}, number = {4}, pages = {241-250}, doi = {10.4155/tde-2019-0011}, pmid = {30991917}, issn = {2041-6008}, mesh = {Biofilms/*drug effects ; Disinfectants/*administration & dosage/pharmacology ; Drug Delivery Systems ; Humans ; Infections/drug therapy/microbiology ; *Magnetite Nanoparticles ; }, abstract = {Biofilm-related diseases contribute to patient morbidity, increased mortality and represent a considerable economic burden. Despite numerous developments in the field of combating biofilms, the most effective treatment method is still the mechanical removal of biofilms or the replacement of a device overgrown with biofilm. Given that the main challenges are the mechanical stability of biofilms, low penetration of biocides and the persistence of cells with reduced metabolic status in them, a promising direction is the use of magnetically controlled materials for their treatment. Current review discusses recent applications of magnetite-based materials as biocide delivery carriers and effectiveness of these conjugates against biofilms.}, } @article {pmid30991317, year = {2019}, author = {Yao, Y and Habimana, O}, title = {Biofilm research within irrigation water distribution systems: Trends, knowledge gaps, and future perspectives.}, journal = {The Science of the total environment}, volume = {673}, number = {}, pages = {254-265}, doi = {10.1016/j.scitotenv.2019.03.464}, pmid = {30991317}, issn = {1879-1026}, mesh = {*Agricultural Irrigation ; Bacteria ; *Biofilms ; *Water Microbiology ; Water Supply ; }, abstract = {Biofilms in irrigation water distribution systems (IWDSs) play an essential role in spreading pathogens, chemical pollutants, and environmental pollutants into downstream irrigated crops and thus should be considered a potential threat to food safety. Although the role of biofilms in drinking water distribution systems has been extensively studied in the last decade, the research on IWDS biofilms in this period has been limited. This review identifies research gaps in the field of IWDS biofilms, provides perspectives on experimental designs for investigating IWDS biofilms, and suggests potential strategies worth pursuing in IWDS management. The current state of the art of IWDS biofilms is discussed, and an analysis of the challenges in IWDS biofilm research is presented. Furthermore, this review proposes useful advanced technologies that allow a practical, in-depth fundamental understanding of IWDS biofilms. In a nutshell, this article provides future directions and insights into detailed experimental designs on a relatively under-reported research topic: "IWDS biofilms."}, } @article {pmid30990402, year = {2019}, author = {Mirzaei, B and Mousavi, SF and Babaei, R and Bahonar, S and Siadat, SD and Shafiee Ardestani, M and Shahrooei, M and Van Eldere, J}, title = {Synthesis of conjugated PIA-rSesC and immunological evaluation against biofilm-forming Staphylococcus epidermidis.}, journal = {Journal of medical microbiology}, volume = {68}, number = {5}, pages = {791-802}, doi = {10.1099/jmm.0.000910}, pmid = {30990402}, issn = {1473-5644}, mesh = {Animals ; Antibodies, Bacterial/*blood ; Biofilms/drug effects/*growth & development ; Female ; Immunogenicity, Vaccine ; Immunoglobulin G/blood ; Mice ; Mice, Inbred BALB C ; Polysaccharides, Bacterial/administration & dosage/*immunology ; Proton Magnetic Resonance Spectroscopy ; Spectroscopy, Fourier Transform Infrared ; Staphylococcal Infections/prevention & control ; Staphylococcal Vaccines/*immunology ; Staphylococcus epidermidis/*immunology ; Vaccines, Conjugate/immunology ; }, abstract = {PURPOSE: Staphylococcus epidermidis is an opportunistic pathogen and a leading cause of morbidity and premature mortality in patients with medical device-related infections, which is a concern in hospitalized patients. Developing a strategy to raise opsonic antibodies against polysaccharide intracellular adhesin (PIA) could be promising for the elimination of colonizing and biofilm-forming S. epidermidis. Following the purification of truncated rSesC protein and PIA, for the first time, PIA was conjugated to rSesC as a carrier to increase the immunogenicity of PIA and its efficacy in mice was evaluated. The structure of the conjugate was analysed using the Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (H1- NMR) methods. Afterwards, the immune response was evaluated by measuring the total IgG, IgG2a and IgG2b titres.

RESULTS: The immunization of mice with the PIA-rSesC conjugate raised the levels of opsonic antibodies, and the vaccinated mice were protected when challenged intravenously by wild-type S. epidermidis strain 1457. Further studies indicated that the conjugated vaccine was able to eliminate S. epidermidis biofilm formation in in vitro or in vivo assays.

CONCLUSION: This study confirms the proposal that the immunization of mice with PIA-rSesC conjugate vaccine could protect against S. epidermidis infection.}, } @article {pmid30988059, year = {2019}, author = {Köseoğlu, VK and Hall, CP and Rodríguez-López, EM and Agaisse, H}, title = {The Autotransporter IcsA Promotes Shigella flexneri Biofilm Formation in the Presence of Bile Salts.}, journal = {Infection and immunity}, volume = {87}, number = {7}, pages = {}, pmid = {30988059}, issn = {1098-5522}, support = {R01 AI073904/AI/NIAID NIH HHS/United States ; R25 GM096955/GM/NIGMS NIH HHS/United States ; T32 AI055432/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Outer Membrane Proteins/metabolism ; Bacterial Proteins/genetics/*physiology ; Bile Acids and Salts/metabolism/*pharmacology ; Biofilms/*drug effects/*growth & development ; DNA-Binding Proteins/genetics/*physiology ; Shigella flexneri/drug effects/metabolism/*physiology ; Transcription Factors/genetics/*physiology ; Type V Secretion Systems/*metabolism ; }, abstract = {Shigella flexneri is an intracellular bacterial pathogen that invades epithelial cells in the colonic mucosa, leading to bloody diarrhea. A previous study showed that S. flexneri forms biofilms in the presence of bile salts, through an unknown mechanism. Here, we investigated the potential role of adhesin-like autotransporter proteins in S. flexneri biofilm formation. BLAST search analysis revealed that the S. flexneri 2457T genome harbors 4 genes, S1242, S1289, S2406, and icsA, encoding adhesin-like autotransporter proteins. Deletion mutants of the S1242, S1289, S2406 and icsA genes were generated and tested for biofilm formation. Phenotypic analysis of the mutant strains revealed that disruption of icsA abolished bile salt-induced biofilm formation. IcsA is an outer membrane protein secreted at the bacterial pole that is required for S. flexneri actin-based motility during intracellular infection. In extracellular biofilms, IcsA was also secreted at the bacterial pole and mediated bacterial cell-cell contacts and aggregative growth in the presence of bile salts. Dissecting individual roles of bile salts showed that deoxycholate is a robust biofilm inducer compared to cholate. The release of the extracellular domain of IcsA through IcsP-mediated cleavage was greater in the presence of cholate, suggesting that the robustness of biofilm formation was inversely correlated with IcsA processing. Accordingly, deletion of icsP abrogated IcsA processing in biofilms and enhanced biofilm formation.}, } @article {pmid30988033, year = {2019}, author = {Cherny, KE and Sauer, K}, title = {Pseudomonas aeruginosa Requires the DNA-Specific Endonuclease EndA To Degrade Extracellular Genomic DNA To Disperse from the Biofilm.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {30988033}, issn = {1098-5530}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; DNA, Bacterial/*genetics ; Deoxyribonuclease I/*genetics ; Endodeoxyribonucleases/*genetics ; Gene Expression Regulation, Bacterial/genetics ; Genomics/methods ; Membrane Proteins/*genetics ; Phenotype ; Pseudomonas aeruginosa/*genetics ; }, abstract = {The dispersion of biofilms is an active process resulting in the release of planktonic cells from the biofilm structure. While much is known about the process of dispersion cue perception and the subsequent modulation of the c-di-GMP pool, little is known about subsequent events resulting in the release of cells from the biofilm. Given that dispersion coincides with void formation and an overall erosion of the biofilm structure, we asked whether dispersion involves degradation of the biofilm matrix. Here, we focused on extracellular genomic DNA (eDNA) due to its almost universal presence in the matrix of biofilm-forming species. We identified two probable nucleases, endA and eddB, and eddA encoding a phosphatase that were significantly increased in transcript abundance in dispersed cells. However, only inactivation of endA but not eddA or eddB impaired dispersion by Pseudomonas aeruginosa biofilms in response to glutamate and nitric oxide (NO). Heterologously produced EndA was found to be secreted and active in degrading genomic DNA. While endA inactivation had little effect on biofilm formation and the presence of eDNA in biofilms, eDNA degradation upon induction of dispersion was impaired. In contrast, induction of endA expression coincided with eDNA degradation and resulted in biofilm dispersion. Thus, released cells demonstrated a hyperattaching phenotype but remained as resistant to tobramycin as biofilm cells from which they egress, indicating EndA-dispersed cells adopted some but not all of the phenotypes associated with dispersed cells. Our findings indicate for the first time a role of DNase EndA in dispersion and suggest weakening of the biofilm matrix is a requisite for biofilm dispersion.IMPORTANCE The finding that exposure to DNase I impairs biofilm formation or leads to the dispersal of early stage biofilms has led to the realization of extracellular genomic DNA (eDNA) as a structural component of the biofilm matrix. However, little is known about the contribution of intrinsic DNases to the weakening of the biofilm matrix and dispersion of established biofilms. Here, we demonstrate for the first time that nucleases are induced in dispersed Pseudomonas aeruginosa cells and are essential to the dispersion response and that degradation of matrix eDNA by endogenously produced/secreted EndA is required for P. aeruginosa biofilm dispersion. Our findings suggest that dispersing cells mediate their active release from the biofilm matrix via the induction of nucleases.}, } @article {pmid30987163, year = {2019}, author = {Khan, F and Manivasagan, P and Lee, JW and Pham, DTN and Oh, J and Kim, YM}, title = {Fucoidan-Stabilized Gold Nanoparticle-Mediated Biofilm Inhibition, Attenuation of Virulence and Motility Properties in Pseudomonas aeruginosa PAO1.}, journal = {Marine drugs}, volume = {17}, number = {4}, pages = {}, pmid = {30987163}, issn = {1660-3397}, support = {20150220//Ministry of Oceans and Fisheries, Republic of Korea/ ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Drug Compounding/methods ; Drug Resistance, Bacterial/drug effects ; Drug Stability ; Gold/chemistry/*pharmacology ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Phaeophyta/chemistry ; Polysaccharides/chemistry/*pharmacology ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/*physiology ; Seaweed/chemistry ; }, abstract = {The emergence of antibiotic resistance in Pseudomonas aeruginosa due to biofilm formation has transformed this opportunistic pathogen into a life-threatening one. Biosynthesized nanoparticles are increasingly being recognized as an effective anti-biofilm strategy to counter P. aeruginosa biofilms. In the present study, gold nanoparticles (AuNPs) were biologically synthesized and stabilized using fucoidan, which is an active compound sourced from brown seaweed. Biosynthesized fucoidan-stabilized AuNPs (F-AuNPs) were subjected to characterization using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission transmission electron microscopy (FE-TEM), dynamic light scattering (DLS), and energy dispersive X-ray diffraction (EDX). The biosynthesized F-AuNPs were then evaluated for their inhibitory effects on P. aeruginosa bacterial growth, biofilm formation, virulence factor production, and bacterial motility. Overall, the activities of F-AuNPs towards P. aeruginosa were varied depending on their concentration. At minimum inhibitory concentration (MIC) (512 µg/mL) and at concentrations above MIC, F-AuNPs exerted antibacterial activity. In contrast, the sub-inhibitory concentration (sub-MIC) levels of F-AuNPs inhibited biofilm formation without affecting bacterial growth, and eradicated matured biofilm. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were identified as 128 µg/mL. Furthermore, sub-MICs of F-AuNPs also attenuated the production of several important virulence factors and impaired bacterial swarming, swimming, and twitching motilities. Findings from the present study provide important insights into the potential of F-AuNPs as an effective new drug for controlling P. aeruginosa-biofilm-related infections.}, } @article {pmid30986604, year = {2019}, author = {Kowalski, MS and Devlin, TR and di Biase, A and Oleszkiewicz, JA}, title = {Controlling cold temperature partial nitritation in moving bed biofilm reactor.}, journal = {Chemosphere}, volume = {227}, number = {}, pages = {216-224}, doi = {10.1016/j.chemosphere.2019.04.025}, pmid = {30986604}, issn = {1879-1298}, mesh = {*Algorithms ; Biofilms ; *Bioreactors ; *Cold Temperature ; Hydrogen-Ion Concentration ; *Nitrification ; Nitrogen/analysis ; Oxygen/analysis ; Wastewater/*chemistry ; }, abstract = {Mainstream partial nitritation was studied at 10 °C in a moving bed biofilm reactor treating synthetic wastewater containing both nitrogen (≈40 mg L[-1]) and organic carbon at COD/N ratio ranging from 1.3 to 2.2. Three different control strategies were investigated to achieve partial nitritation. Initially, biofilm age was controlled by incorporating a media replacement strategy. Next, separately from the media replacement, oxygen limited conditions were investigated and finally pH control was incorporated together with oxygen limitation. Successful partial nitritation was achieved only by combining oxygen limitation with pH control. The average NH4-N concentration was equal to 16.0 ± 1.6 mg L[-1] and average NO2-N concentration was equal to 15.7 ± 2.4 mg L[-1] during steady state partial nitritation. The average residual NO3-N concentration was equal to 2.6 ± 2.2 mg L[-1]. The results obtained from this study prove for the first time that partial nitritation can be successfully controlled in a biofilm reactor treating wastewater with low nitrogen concentration, relatively high COD/N ratio and at low temperature. An algorithm for dynamic process control of partial nitritation has been also developed.}, } @article {pmid30986593, year = {2019}, author = {Liu, J and Zhou, J and Xu, N and He, A and Xin, F and Ma, J and Fang, Y and Zhang, W and Liu, S and Jiang, M and Dong, W}, title = {Performance evaluation of a lab-scale moving bed biofilm reactor (MBBR) using polyethylene as support material in the treatment of wastewater contaminated with terephthalic acid.}, journal = {Chemosphere}, volume = {227}, number = {}, pages = {117-123}, doi = {10.1016/j.chemosphere.2019.03.186}, pmid = {30986593}, issn = {1879-1298}, mesh = {Biodegradation, Environmental ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Biomass ; Bioreactors ; Coloring Agents ; Phthalic Acids/analysis/*metabolism ; Polyethylene/chemistry ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; Water Pollutants, Chemical/analysis/*metabolism ; }, abstract = {Untreated terephthalic acid (TPA) wastewaters with high organic loads will cause severe environmental pollution problems. In this study, a lab-scale moving bed biofilm reactor, where biomass of Delftia sp. WL-3 is attached to polypropylene carrier elements, has been tested for TPA bioremediation at 25-27 °C. The system achieved stable operation after a short 15-day start-up period. During the operation period of 65 days, stable chemical oxygen demand (COD) and TPA removal efficiencies of 68% and 76% were maintained with an organic load rate (OLR) and hydraulic retention time of 2.5 kg COD·(m[3]·d)[-1] and 24 h, respectively. In addition, the Scanning Electron Microscope (SEM) showed that high-densities of WL-3 biomass accumulated on the surface of the carrier and formed a rich biofilm, indicating polypropylene carrier can improve the degradation efficiency. On the contrary, the biodegradation ability of stain WL-3 without the polypropylene carrier declined significantly with removal efficiencies of 10% and 15% for COD and TPA. Furthermore, the system exhibited excellent robustness to different OLR and influent matrix ratios, indicating its potential for applications in the treatment of TPA-containment wastewater in the field.}, } @article {pmid30986518, year = {2019}, author = {Yoo, Y and Seo, DH and Lee, H and Cho, ES and Song, NE and Nam, TG and Nam, YD and Seo, MJ}, title = {Inhibitory effect of Bacillus velezensis on biofilm formation by Streptococcus mutans.}, journal = {Journal of biotechnology}, volume = {298}, number = {}, pages = {57-63}, doi = {10.1016/j.jbiotec.2019.04.009}, pmid = {30986518}, issn = {1873-4863}, mesh = {1-Deoxynojirimycin/*metabolism ; Bacillus/*metabolism ; Bacterial Proteins/genetics ; Biofilms/growth & development ; Dental Caries/*microbiology/prevention & control ; Gene Expression Regulation, Bacterial ; Glucosyltransferases/antagonists & inhibitors/genetics ; Humans ; Streptococcus mutans/*metabolism/pathogenicity ; }, abstract = {Streptococcus mutans plays a key role in the development of dental caries and promotes the formation of oral biofilm produced by glucosyltransferases (GTFs). Bacillus velezensis K68 was isolated from traditional fermented foods and inhibits biofilm formation mediated by S. mutans. Gene amplification results demonstrated that B. velezensis K68 contained genes for the biosynthesis of 1-deoxynojirimycin (1-DNJ), a known GTF expression inhibitor. The presence of the GabT1, Yktc1, and GutB1 genes required for 1-DNJ synthesis in B. velezensis K68 was confirmed. Supernatant from B. velezensis K68 culture medium inhibited biofilm formation by 84% when S. mutans was cultured for 48 h, and inhibited it maximally when 1% glucose was added to the S. mutans culture medium as a GTF substrate. In addition, supernatant from B. velezensis K68 medium containing 3 ppb 1-DNJ decreased S. mutans cell surface hydrophobicity by 79.0 ± 0.8% compared with that of untreated control. The supernatant containing 1-DNJ decreased S. mutans adherence by 99.97% and 98.83% under sugar-dependent and sugar-independent conditions, respectively. S. mutans treated with the supernatant exhibited significantly reduced expression of the essential GTF genes gtfB, gtfC, and gtfD compared to that in the untreated group. Thus, B. velezensis inhibits biofilm formation, adhesion, and GTF gene expression of S. mutans through 1-DNJ production.}, } @article {pmid30985241, year = {2019}, author = {Kwiecinski, JM and Jacobsson, G and Horswill, AR and Josefsson, E and Jin, T}, title = {Biofilm formation by Staphylococcus aureus clinical isolates correlates with the infection type.}, journal = {Infectious diseases (London, England)}, volume = {51}, number = {6}, pages = {446-451}, pmid = {30985241}, issn = {2374-4243}, support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus ; Skin Diseases/microbiology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/classification/*pathogenicity/*physiology ; Trans-Activators/genetics ; }, abstract = {BACKGROUND: Biofilms are involved in many Staphylococcus aureus infections, but relation of biofilm formation and the infection types or the clinical outcomes remain unclear.

METHODS: We measured biofilm formation, with a microtiter plate assay, of a collection of methicillin-sensitive clinical isolates from 159 invasive S. aureus infections, encompassing all cases occurring within a hospital catchment area during two years, and from additional 49 non-invasive skin infections from the same region. Results were related to available clinical and microbiological documentation.

RESULTS: Isolates from medical device infections (intravenous line-associated and prosthetic joint infections), as well as isolates from superficial skin infections, were particularly proficient in forming biofilms. No increased biofilm-forming capacity was seen in isolates from endocarditis, osteomyelitis, or other infections. There was also a correlation of biofilm formation with the agr type of the isolates. Thicker biofilms were more resistant to antibiotic treatment in vitro. No correlation between biofilm formation and clinical outcomes was noted.

CONCLUSIONS: S. aureus isolates from 'classical' biofilm-related infections, but also from superficial skin infections, are especially proficient in forming biofilms. There is, however, no obvious relation of biofilm-forming capacity of isolates and the clinical outcome of the infection, and more studies on this issue are needed.}, } @article {pmid30984136, year = {2019}, author = {Bellenberg, S and Huynh, D and Poetsch, A and Sand, W and Vera, M}, title = {Proteomics Reveal Enhanced Oxidative Stress Responses and Metabolic Adaptation in Acidithiobacillus ferrooxidans Biofilm Cells on Pyrite.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {592}, pmid = {30984136}, issn = {1664-302X}, abstract = {Reactive oxygen species (ROS) cause oxidative stress and growth inhibition by inactivation of essential enzymes, DNA and lipid damage in microbial cells. Acid mine drainage (AMD) ecosystems are characterized by low pH values, enhanced levels of metal ions and low species abundance. Furthermore, metal sulfides, such as pyrite and chalcopyrite, generate extracellular ROS upon exposure to acidic water. Consequently, oxidative stress management is especially important in acidophilic leaching microorganisms present in industrial biomining operations, especially when forming biofilms on metal sulfides. Several adaptive mechanisms have been described, but the molecular repertoire of responses upon exposure to pyrite and the presence of ROS are not thoroughly understood in acidophiles. In this study the impact of the addition of H2O2 on iron oxidation activity in Acidithiobacillus ferrooxidans DSM 14882[T] was investigated. Iron(II)- or sulfur-grown cells showed a higher sensitivity toward H2O2 than pyrite-grown ones. In order to elucidate which molecular responses may be involved, we used shot-gun proteomics and compared proteomes of cells grown with iron(II)-ions against biofilm cells, grown for 5 days in presence of pyrite as sole energy source. In total 1157 proteins were identified. 213 and 207 ones were found to have increased levels in iron(II) ion-grown or pyrite-biofilm cells, respectively. Proteins associated with inorganic sulfur compound (ISC) oxidation were among the latter. In total, 80 proteins involved in ROS degradation, thiol redox regulation, macromolecule repair mechanisms, biosynthesis of antioxidants, as well as metal and oxygen homeostasis were found. 42 of these proteins had no significant changes in abundance, while 30 proteins had increased levels in pyrite-biofilm cells. New insights in ROS mitigation strategies, such as importance of globins for oxygen homeostasis and prevention of unspecific reactions of free oxygen that generate ROS are presented for A. ferrooxidans biofilm cells. Furthermore, proteomic analyses provide insights in adaptations of carbon fixation and oxidative phosphorylation pathways under these two growth conditions.}, } @article {pmid30983797, year = {2019}, author = {Karigoudar, RM and Karigoudar, MH and Wavare, SM and Mangalgi, SS}, title = {Detection of biofilm among uropathogenic Escherichia coli and its correlation with antibiotic resistance pattern.}, journal = {Journal of laboratory physicians}, volume = {11}, number = {1}, pages = {17-22}, pmid = {30983797}, issn = {0974-2727}, abstract = {BACKGROUND: Escherichia coli accounts for 70%-95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation.

MATERIALS AND METHODS: A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby-Bauer disc diffusion method on Muller-Hinton agar plate.

RESULTS: Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05).

CONCLUSION: A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.}, } @article {pmid30981136, year = {2019}, author = {Gandra, TKV and Volcan, D and Kroning, IS and Marini, N and de Oliveira, AC and Bastos, CP and da Silva, WP}, title = {Expression levels of the agr locus and prfA gene during biofilm formation by Listeria monocytogenes on stainless steel and polystyrene during 8 to 48 h of incubation 10 to 37 °C.}, journal = {International journal of food microbiology}, volume = {300}, number = {}, pages = {1-7}, doi = {10.1016/j.ijfoodmicro.2019.03.021}, pmid = {30981136}, issn = {1879-3460}, mesh = {Bacterial Proteins/*genetics ; *Biofilms ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Listeria monocytogenes/*genetics ; Peptide Termination Factors/*genetics ; *Polystyrenes ; *Stainless Steel ; Temperature ; }, abstract = {The objective of this study was to compare the gene expression levels of the agr locus and prfA gene during adhesion and biofilm formation by four L. monocytogenes isolates (2 biofilm-forming and 2 non-forming) on stainless steel and polystyrene surfaces at different temperatures (10 °C, 20 °C and 37 °C), and times (8 h, 12 h, 24 h and 48 h). The agrA and prfA genes were expressed at higher levels than the agrBCD genes. The levels of agr locus expression were higher in the biofilm-forming strains, and the greatest difference between biofilm-forming and non-forming isolates was observed for the agrB, agrC and agrD genes. However, no difference in the expression of the prfA gene was seen among the isolates, independent of the biofilm-forming ability. Maximum expression of the agr locus and prfA gene was observed at 37 °C, whereas expression was lowest at 10 °C. The agr locus, and particularly the agrB, agrC and agrD genes, is important in the initial adhesion phase of biofilm production by L. monocytogenes, with this expression independent of prfA. In addition, the agr locus and prfA gene expression levels were strongly influenced by time and temperature.}, } @article {pmid30981076, year = {2019}, author = {Sjödin, T}, title = {The pH-dependent effect of cationic and non-ionic delmopinol on planktonic and biofilm bacteria.}, journal = {Archives of oral biology}, volume = {102}, number = {}, pages = {101-105}, doi = {10.1016/j.archoralbio.2019.03.014}, pmid = {30981076}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests ; Morpholines ; *Plankton ; }, abstract = {OBJECTIVES: The primary purpose was to evaluate the antimicrobial effects of cationic and non-ionic delmopinol on planktonic and biofilm bacteria.

METHODS: Determination of the minimum inhibitory concentrations on planktonic and biofilm bacteria was performed below and above the pKa-value of delmopinol. Test bacteria were Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. Comparisons were made with three antimicrobial agents and "quaternary" delmopinol. Synergy testing of delmopinol was determined with serial dilutions of delmopinol with the other compounds in a checkerboard fashion, and the fractional inhibitory concentration index (FIC) was calculated.

RESULTS: Delmopinol showed minor differences between its MIC- and MBEC-values for all bacterial strains (MBEC/MIC-ratios of 1-2). For the other compounds the difference between their MIC- and MBEC-values were higher and varied considerably between the bacteria. The MIC- and MBEC-concentrations were lower at pH where the non-ionic form of delmopinol dominates. "Quaternary" delmopinol showed the same MIC-concentrations as delmopinol, but needed much higher concentrations to kill biofilm bacteria. Synergy testing showed FIC-indices of 0.5-1.

CONCLUSIONS: The biofilm penetration of non-ionic delmopinol is better than for cationic delmopinol. Likewise, the cationic test reference samples exerted limited biofilm penetration. The increased efficacy of non-ionic delmopinol is probably due to reduced binding to negative groups in the extracellular matrix of polymeric substances surrounding biofilm bacteria. It is also proposed that the non-ionised form of delmopinol deposits on the biofilm surface. Higher amounts of delmopinol than expected will therefore accumulate. Combinations of delmopinol with other compounds suggests an additive antimicrobial effect.}, } @article {pmid30980880, year = {2019}, author = {Liu, L and Zheng, S}, title = {Transcriptional regulation of Yersinia pestis biofilm formation.}, journal = {Microbial pathogenesis}, volume = {131}, number = {}, pages = {212-217}, doi = {10.1016/j.micpath.2019.04.011}, pmid = {30980880}, issn = {1096-1208}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Disease Transmission, Infectious ; Environment ; Gastrointestinal Tract/microbiology ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Host-Pathogen Interactions ; Insect Vectors/microbiology ; Plague/transmission ; Siphonaptera/microbiology ; Transcription Factors ; Yersinia pestis/*genetics/physiology ; }, abstract = {Yersinia pestis, the causative agent of plague, is transmitted primarily by infected fleas in nature. Y. pestis can produce biofilms that block flea's proventriculus and promote flea-borne transmission. Transcriptional regulation of Y. pestis biofilm formation plays an important role in the response to complex changes in environments, including temperature, pH, oxidative stress, and restrictive nutrition conditions, and contributes to Y. pestis growth, reproduction, transmission, and pathogenesis. A set of transcriptional regulators involved in Y. pestis biofilm production simultaneously controls a variety of biological functions and physiological pathways. Interactions between these regulators contribute to the development of Y. pestis gene regulatory networks, which are helpful for a quick response to complex environmental changes and better survival. The roles of crucial factors and regulators involved in response to complex environmental signals and Y. pestis biofilm formation as well as the precise gene regulatory networks are discussed in this review, which will give a better understanding of the complicated mechanisms of transcriptional regulation in Y. pestis biofilm formation.}, } @article {pmid30980362, year = {2019}, author = {Shahrour, H and Ferrer-Espada, R and Dandache, I and Bárcena-Varela, S and Sánchez-Gómez, S and Chokr, A and Martinez-de-Tejada, G}, title = {AMPs as Anti-biofilm Agents for Human Therapy and Prophylaxis.}, journal = {Advances in experimental medicine and biology}, volume = {1117}, number = {}, pages = {257-279}, doi = {10.1007/978-981-13-3588-4_14}, pmid = {30980362}, issn = {0065-2598}, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; *Biofilms ; Humans ; }, abstract = {Microbial cells show a strong natural tendency to adhere to surfaces and to colonize them by forming complex communities called biofilms. In this growth mode, biofilm-forming cells encase themselves inside a dense matrix which efficiently protects them against antimicrobial agents and effectors of the immune system. Moreover, at the physiological level, biofilms contain a very heterogeneous cell population including metabolically inactive organisms and persisters, which are highly tolerant to antibiotics. The majority of human infectious diseases are caused by biofilm-forming microorganisms which are responsible for pathologies such as cystic fibrosis, infective endocarditis, pneumonia, wound infections, dental caries, infections of indwelling devices, etc. AMPs are well suited to combat biofilms because of their potent bactericidal activity of broad spectrum (including resting cells and persisters) and their ability to first penetrate and then to disorganize these structures. In addition, AMPs frequently synergize with antimicrobial compounds and were recently reported to repress the molecular pathways leading to biofilm formation. Finally, there is a very active research to develop AMP-containing coatings that can prevent biofilm formation by killing microbial cells on contact or by locally releasing their active principle. In this chapter we will describe these strategies and discuss the perspectives of the use of AMPs as anti-biofilm agents for human therapy and prophylaxis.}, } @article {pmid30979839, year = {2019}, author = {Pandin, C and Darsonval, M and Mayeur, C and Le Coq, D and Aymerich, S and Briandet, R}, title = {Biofilm Formation and Synthesis of Antimicrobial Compounds by the Biocontrol Agent Bacillus velezensis QST713 in an Agaricus bisporus Compost Micromodel.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {12}, pages = {}, pmid = {30979839}, issn = {1098-5336}, mesh = {Agaricus/physiology ; Anti-Infective Agents/*chemistry ; Bacillus/*chemistry/genetics/*physiology ; *Biofilms ; Biological Control Agents/*chemistry ; *Composting ; Gene Expression Regulation, Bacterial/physiology ; }, abstract = {Bacillus velezensis QST713 is widely used as a biological control agent for crop protection and disease suppression. This strain is used industrially in France for the protection of Agaricus bisporus against Trichoderma aggressivum f. europaeum, which causes green mold disease. The efficacy of this biocontrol process was evaluated in a previous study, yet the mode of its action has not been explored under production conditions. In order to decipher the underlying biocontrol mechanisms for effective biofilm formation by strain QST713 in the compost and for the involvement of antimicrobial compounds, we developed a simplified micromodel for the culture of A. bisporus during its early culture cycle. By using this micromodel system, we studied the transcriptional response of strain QST713 in the presence or absence of A. bisporus and/or T. aggressivum in axenic industrial compost. We report the overexpression of several genes of the biocontrol agent involved in biofilm formation in the compost compared to their expression during growth in broth compost extract either in the exponential growth phase (the epsC, blsA, and tapA genes) or in the stationary growth phase (the tapA gene), while a gene encoding a flagellar protein (hag) was underexpressed. We also report the overexpression of Bacillus velezensis QST713 genes related to surfactin (srfAA) and fengycin (fenA) production in the presence of the fungal pathogen in the compost.IMPORTANCE Biocontrol agents are increasingly used to replace chemical pesticides to prevent crop diseases. In the button mushroom field in France, the use of Bacillus velezensis QST713 as a biocontrol agent against the green mold Trichoderma aggressivum has been shown to be efficient. However, the biocontrol mechanisms effective in the Agaricus bisporus/Trichoderma aggressivum/Bacillus velezensis QST713 pathosystem are still unknown. Our paper focuses on the exploration of the bioprotection mechanisms of the biocontrol agent Bacillus velezensis QST713 during culture of the button mushroom (Agaricus bisporus) in a micromodel culture system to study the specific response of strain QST713 in the presence of T. aggressivum and/or A. bisporus.}, } @article {pmid30978919, year = {2019}, author = {Farkash, Y and Feldman, M and Ginsburg, I and Steinberg, D and Shalish, M}, title = {Polyphenols Inhibit Candida albicans and Streptococcus mutans Biofilm Formation.}, journal = {Dentistry journal}, volume = {7}, number = {2}, pages = {}, pmid = {30978919}, issn = {2304-6767}, abstract = {Background: Streptococcus mutans (S. mutans) and Candida albicans (C. albicans) are two major contributors to dental caries. They have a symbiotic relationship, allowing them to create an enhanced biofilm. Our goal was to examine whether two natural polyphenols (Padma hepaten (PH) and a polyphenol extraction from green tea (PPFGT)) could inhibit the caries-inducing properties of S. mutans and C. albicans. Methods: Co-species biofilms of S. mutans and C. albicans were grown in the presence of PH and PPFGT. Biofilm formation was tested spectrophotometrically. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy. Biofilm development was also tested on orthodontic surfaces (Essix) to assess biofilm inhibition ability on such an orthodontic appliance. Results: PPFGT and PH dose-dependently inhibited biofilm formation without affecting the planktonic growth. We found a significant reduction in biofilm total biomass using 0.625 mg/mL PPFGT and 0.16 mg/mL PH. A concentration of 0.31 mg/mL PPFGT and 0.16 mg/mL PH inhibited the total cell growth by 54% and EPS secretion by 81%. A reduction in biofilm formation and EPS secretion was also observed on orthodontic PVC surfaces. Conclusions: The polyphenolic extractions PPFGT and PH have an inhibitory effect on S. mutans and C. albicans biofilm formation and EPS secretion.}, } @article {pmid30976947, year = {2019}, author = {Lee, YS and Park, W}, title = {Enhanced calcium carbonate-biofilm complex formation by alkali-generating Lysinibacillus boronitolerans YS11 and alkaliphilic Bacillus sp. AK13.}, journal = {AMB Express}, volume = {9}, number = {1}, pages = {49}, pmid = {30976947}, issn = {2191-0855}, support = {19SCIP-B103706-05//Ministry of Land, Infrastructure and Transport, Republic of Korea/ ; }, abstract = {Microbially induced calcium carbonate (CaCO3) precipitation (MICP) is a process where microbes induce condition favorable for CaCO3 formation through metabolic activities by increasing the pH or carbonate ions when calcium is near. The molecular and ecological basis of CaCO3 precipitating (CCP) bacteria has been poorly illuminated. Here, we showed that increased pH levels by deamination of amino acids is a driving force toward MICP using alkalitolerant Lysinibacillus boronitolerans YS11 as a model species of non-ureolytic CCP bacteria. This alkaline generation also facilitates the growth of neighboring alkaliphilic Bacillus sp. AK13, which could alter characteristics of MICP by changing the size and shape of CaCO3 minerals. Furthermore, we showed CaCO3 that precipitates earlier in an experiment modifies membrane rigidity of YS11 strain via upregulation of branched chain fatty acid synthesis. This work closely examines MICP conditions by deamination and the effect of MICP on cell membrane rigidity and crystal formation for the first time.}, } @article {pmid30975483, year = {2019}, author = {Llama-Palacios, A and Sánchez, MC and Díaz, LA and Cabal, B and Suárez, M and Moya, JS and Torrecillas, R and Figuero, E and Sanz, M and Herrera, D}, title = {In vitro biofilm formation on different ceramic biomaterial surfaces: Coating with two bactericidal glasses.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {6}, pages = {883-892}, doi = {10.1016/j.dental.2019.03.003}, pmid = {30975483}, issn = {1879-0097}, mesh = {*Biocompatible Materials ; Biofilms ; Ceramics ; *Fusobacterium nucleatum ; Porphyromonas gingivalis ; Streptococcus oralis ; }, abstract = {OBJECTIVES: To compare biofilm formation on the surface of different ceramic biomaterials to be used in implant dentistry.

METHODS: In vitro biofilm formation was investigated from mixtures of standard reference strains of Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Sterile ceramic calcium hydroxyapatite discs (HA) as control, sterile Al2O3/Ce-TZP nanocomposite sandblasted discs (material A1) and sterile Al2O3/Ce-TZP nanocomposite sandblasted discs and coated with two types of antimicrobial glasses (materials A2 and A3) were used. Biofilms were grown on the four surfaces and evaluated after 12, 24, 48 and 72 h of incubation. Biofilms were examined by confocal laser scanning microscopy (CLSM). In addition, counts of live bacterial cells of the target species A. actinomycetemcomitans, F. nucleatum and P. gingivalis were calculated by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA). For data analysis, bacterial counts were compared with a multivariate general lineal model.

RESULTS: Using CLSM, cell vitality decreased in A2 and A3. With qPCR-PMA, significant differences in vitality were observed forA. actinomycetemcomitans in A3 after 48 and 72 h of incubation. With respect to the development of the biofilms, a significant increase in counts on HA and materials A1 and A2 was observed for A. actinomycetemcomitans and F. nucleatum. Conversely, for P. gingivalis, no differences were found for HA and materials A1 and A2.

SIGNIFICANCE: Differences in biofilm formation were detected among the different tested materials. The ceramic material A3 has an effect on the vitality of A. actinomycetemcomitans growing in an in vitro biofilm model.}, } @article {pmid30972606, year = {2019}, author = {El-Banna, T and Abd El-Aziz, A and Sonbol, F and El-Ekhnawy, E}, title = {Adaptation of Pseudomonas aeruginosa clinical isolates to benzalkonium chloride retards its growth and enhances biofilm production.}, journal = {Molecular biology reports}, volume = {46}, number = {3}, pages = {3437-3443}, pmid = {30972606}, issn = {1573-4978}, mesh = {Acclimatization/drug effects ; Adaptation, Biological/physiology ; Adaptation, Physiological/drug effects ; Anti-Bacterial Agents/pharmacology ; Benzalkonium Compounds/metabolism/*pharmacology ; Biofilms/drug effects ; Disinfectants/pharmacology ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/growth & development/*metabolism ; }, abstract = {The increasing percentage of Pseudomonas aeruginosa strains that are resistant to multiple antibiotics is a global problem. The exposure of P. aeruginosa isolates to repeated sub lethal concentrations of biocides in hospitals and communities may be one of the causes leading to increased antibiotic resistance. Benzalkonium chloride (BAC) is widely used as disinfectant and preservative. This study investigated the effect of exposure of P. aeruginosa clinical isolates to sub lethal concentrations of BAC on their antibiotic resistance, growth process and biofilm formation. The collected 43 P. aeruginosa clinical isolates were daily subjected to increasing sub lethal concentrations of BAC. The effect of adaptation on antibiotic resistance, growth process, cell surface hydrophobicity and biofilm formation of P. aeruginosa isolates were examined. Interestingly, Most P. aeruginosa isolates adapted to BAC showed an increase in antibiotic resistance and 66% of the isolates showed retardation of growth, 63% showed increased cell surface hydrophobicity and 23.5% exhibited enhanced biofilm formation by crystal violet assay. To define whether the effect of BAC adaptation on biofilm production was manifested at the transcriptional level, quantitative RT-PCR was used. We found that 60% of the tested isolates showed overexpression of ndvB biofilm gene. More efforts are required to diminish the increasing use of BAC to avoid bacterial adaptation to this biocide with subsequent retardation of growth and enhanced biofilm formation which could lead to antibiotic resistance and treatment failure of infections caused by this opportunistic pathogen.}, } @article {pmid30972161, year = {2019}, author = {Du, Z and Huang, Y and Chen, Y and Chen, Y}, title = {Combination effects of baicalin with levofloxacin against biofilm-related infections.}, journal = {American journal of translational research}, volume = {11}, number = {3}, pages = {1270-1281}, pmid = {30972161}, issn = {1943-8141}, abstract = {It is important to improve the existing techniques and develop new strategies to prevent bacterial biofilm formation. In this in vitro study, biofilms were established by a clinically isolated strain of Staphylococcus aureus 17546 (t037). Different concentrations of baicalin were added to 3- and 7-day biofilms. Based on colony counts and quantitative analysis of the biomass, sub-minimum inhibitory concentrations (sub-MICs) (1024, 512 or 256 μg/mL) of baicalin clearly decreased the number of bacterial colonies and biomass in vitro. Fluorescence microscopy revealed that sub-MICs (1024, 512, or 256 μg/mL) of baicalin inhibited bacterial adherence to the carrier surface and decreased polysaccharide production. Moreover, baicalin disrupted biofilms and exhibited synergistic effects with levofloxacin. Virulence factors were assessed by western blotting and real-time quantitative polymerase chain reaction, confirming that staphylococcal enterotoxin A, α-haemolysin and coagulase production decreased after baicalin treatment. Additionally, baicalin increased production of thermonuclease in S. aureus, and baicalin at 1024 and 512 μg/mL downregulated agrA expression. Based on these findings, the combination of baicalin with levofloxacin might be a new, feasible strategy for treating S. aureus biofilm-related infections. Baicalin may serve as a new inhibitor that modulates S. aureus virulence factors.}, } @article {pmid30971289, year = {2019}, author = {Declercq, AM and Cai, W and Naranjo, E and Thongda, W and Eeckhaut, V and Bauwens, E and Arias, C and De La Fuente, L and Beck, BH and Lange, MD and Peatman, E and Haesebrouck, F and Aerts, J and Decostere, A}, title = {Evidence that the stress hormone cortisol regulates biofilm formation differently among Flavobacterium columnare isolates.}, journal = {Veterinary research}, volume = {50}, number = {1}, pages = {24}, pmid = {30971289}, issn = {1297-9716}, support = {BOF.PDO.2015.0020.01//Bijzonder Onderzoeksfonds/ ; V423316N//Fonds Wetenschappelijk Onderzoek/ ; }, mesh = {Animals ; Bacterial Adhesion/*genetics ; Biofilms/drug effects/*growth & development ; Carps/microbiology ; Dose-Response Relationship, Drug ; Flavobacterium/drug effects/genetics/pathogenicity/*physiology ; *Gene Expression ; Genes, Bacterial/*physiology ; Hydrocortisone/administration & dosage/*metabolism ; Lab-On-A-Chip Devices/veterinary ; Plankton/drug effects/growth & development ; Virulence ; }, abstract = {The impact of cortisol on Flavobacterium columnare biofilm formation was explored. Firstly, the dynamics of biofilm formation by one highly (HV) and one low virulent (LV) F. columnare isolate with and without the stress hormone cortisol under microfluidic flow conditions was characterized. This to confirm that F. columnare cells could form biofilm under cortisol supplementation, and to compare the temporal and structural differences between different treatment groups. One trial revealed that in both isolates cell aggregates resembling biofilms occurred within 7-h post-inoculation. Consequently, cell clusters were sloughed away, followed by a rebuilding of bacterial cell aggregates, suggestive for a high spreading capacity. While the HV isolate revealed cell aggregates formed upstream at all time-points, for the LV isolate this was only seen upon cortisol supplementation. Secondly, the transcriptional effect of genes (gldK, gldL, gldM, gldN, sprA, sprE, sprT, and porV) belonging to the Type IX secretion system involved in gliding motility was investigated in planktonic and biofilm cells of a HV and LV isolate to which no, a low (LD) or high (HD) dose of cortisol was added. Significantly lower expression of gliding genes gldK, gldL, gldM and gldN, and of protein secretion regulator porV was seen in the LV isolate planktonic cells supplemented with a HD-cortisol. The LV isolate biofilm cells treated with the HD-cortisol showed a significant upregulation of sprT, encoding mobile surface adhesion important in bacterial colonization. This is the first evidence for the co-regulatory effect of cortisol on biofilm formation and F. columnare gliding gene expression.}, } @article {pmid30970480, year = {2019}, author = {Jepsen, R and He, K and Blaney, L and Swan, C}, title = {Effects of antimicrobial exposure on detrital biofilm metabolism in urban and rural stream environments.}, journal = {The Science of the total environment}, volume = {666}, number = {}, pages = {1151-1160}, doi = {10.1016/j.scitotenv.2019.02.254}, pmid = {30970480}, issn = {1879-1026}, mesh = {Anti-Bacterial Agents/*adverse effects ; Antifungal Agents/*adverse effects ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Biological Oxygen Demand Analysis ; Ciprofloxacin/*adverse effects ; Cities ; Imidazoles/*adverse effects ; Maryland ; Plant Leaves/microbiology ; Rivers/*microbiology ; }, abstract = {The occurrence of antimicrobials and other pharmaceuticals in streams is increasingly being reported, yet the impacts of these contaminants of emerging concern on aquatic ecosystems are relatively unknown. Bacteria and fungi are vital components of stream environments and, therefore, exposure to antimicrobials may have important consequences for ecosystem services, such as carbon cycling. The objective of this study was to investigate how two antimicrobials, ciprofloxacin and climbazole, impact detrital biofilm metabolism in urban and rural streams. To establish baseline conditions, the biological oxygen demand (BOD) of red maple (Acer rubrum) biofilms was measured in one urban and one rural stream. In mesocosm studies, the BOD of biofilms on single- and mixed-species leaf litter from the same sites was measured after exposure to 10 μg/L of the antimicrobials, both in combination and individually. The presence of ciprofloxacin and climbazole did not affect BOD compared to the controls at the urban site, although significant differences were identified for select treatments at the rural site. In addition, the BOD of mixed-leaf biofilms was not significantly different from that of single species litter after exposure. Overall, exposure to 10 μg/L of the antimicrobials did not significantly impact community-level carbon processing by the leaf biofilms, and leaf mixtures did not result in increased biofilm BOD compared to single species leaves. The outcomes of this work demonstrate a need for further research for the understanding the effects of antimicrobials on rural streams to prevent unintended consequences to ecological processes and biota from future development, leaking septic systems, and wastewater spills.}, } @article {pmid30969774, year = {2019}, author = {Liébana, R and Modin, O and Persson, F and Szabó, E and Hermansson, M and Wilén, BM}, title = {Combined Deterministic and Stochastic Processes Control Microbial Succession in Replicate Granular Biofilm Reactors.}, journal = {Environmental science & technology}, volume = {53}, number = {9}, pages = {4912-4921}, doi = {10.1021/acs.est.8b06669}, pmid = {30969774}, issn = {1520-5851}, mesh = {Biofilms ; *Bioreactors ; Reproducibility of Results ; *Sewage ; Stochastic Processes ; Waste Disposal, Fluid ; }, abstract = {Granular sludge is an efficient and compact biofilm process for wastewater treatment. However, the ecological factors involved in microbial community assembly during the granular biofilm formation are poorly understood, and little is known about the reproducibility of the process. Here, three replicate bioreactors were used to investigate microbial succession during the formation of granular biofilms. We identified three successional phases. During the initial phase, the successional turnover was high and α-diversity decreased as a result of the selection of taxa adapted to grow on acetate and form aggregates. Despite these dynamic changes, the microbial communities in the replicate reactors were similar. The second successional phase occurred when the settling time was rapidly decreased to selectively retain granules in the reactors. The influence of stochasticity on succession increased and new niches were created as granules emerged, resulting in temporarily increased α-diversity. The third successional phase occurred when the settling time was kept stable and granules dominated the biomass. Turnover was low, and selection resulted in the same abundant taxa in the reactors, but drift, which mostly affected low-abundant community members, caused the community in one reactor to diverge from the other two. Even so, performance was stable and similar between reactors.}, } @article {pmid30967851, year = {2019}, author = {Rojo-Molinero, E and Macià, MD and Oliver, A}, title = {Social Behavior of Antibiotic Resistant Mutants Within Pseudomonas aeruginosa Biofilm Communities.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {570}, pmid = {30967851}, issn = {1664-302X}, abstract = {The complex spatial structure and the heterogeneity within biofilms lead to the emergence of specific social behaviors. However, the impact of resistant mutants within bacterial communities is still mostly unknown. Thus, we determined whether antibiotic resistant mutants display selfish or altruistic behaviors in mixed Pseudomonas aeruginosa biofilms exposed to antibiotics. ECFP-tagged P. aeruginosa strain PAO1 and its EYFP-tagged derivatives hyperproducing the β-lactamase AmpC or the efflux pump MexAB-OprM were used to develop single or mixed biofilms. Mature biofilms were challenged with different concentrations of β-lactams to monitor biofilm structural dynamics, using confocal laser scanning microscopy (CLSM), and population dynamics, through enumeration of viable cells. While exposure of single wild-type PAO1 biofilms to β-lactams lead to a major reduction in bacterial load, it had little effect on biofilms formed by the resistant mutants. However, the most reveling finding was that bacterial load of wild-type PAO1 was significantly increased when growing in mixed biofilms compared to single biofilms. In agreement with CFU enumeration data, CLSM images revealed the amplification of the resistant mutants and their protection of susceptible populations. These findings show that mutants expressing diverse resistance mechanisms, including β-lactamases, but also, as evidenced for the first time, efflux pumps, protect the whole biofilm community, preserving susceptible populations from the effect of antibiotics. Thus, these results are a step forward to understanding antibiotic resistance dynamics in biofilms, as well as the population biology of bacterial pathogens in chronic infections, where the coexistence of susceptible and resistant variants is a hallmark.}, } @article {pmid30965175, year = {2019}, author = {Tombola, R and Buttiglieri, G and Auset, M and Gonzalez-Olmos, R}, title = {Recycled corrugated wire hose cover as biological carriers for greywater treatment in a sequential batch biofilm reactor.}, journal = {Journal of environmental management}, volume = {240}, number = {}, pages = {475-484}, doi = {10.1016/j.jenvman.2019.02.116}, pmid = {30965175}, issn = {1095-8630}, mesh = {*Ammonium Compounds ; Biofilms ; *Bioreactors ; Recycling ; Waste Disposal, Fluid ; }, abstract = {Greywater treatment and reuse can be considered a promising option, in particular in water scarcity affected areas. In this work a waste material, namely recycled corrugated wire hose cover, was applied as an alternative and cheap carrier in a sequencing batch biofilm reactor (SBBR) for greywater treatment. The bioreactor performance was studied in terms of organic matter, nitrogen and micropollutant removal. Four operational stages were investigated: i) inoculation of the carriers; ii) greywater treatment with suspended biomass; iii) synthetic and iv) real greywater treatment with inoculated carriers in the SBBR. The SBBR could treat real greywater showing high removal efficiencies for COD (86.5 ± 5.8%), ammonium (98.4 ± 1.4%) and total nitrogen (71.4 ± 8.2%). The obtained efficiencies were similar to the ones obtained with commercial carriers and to other treatments such as MBBR or MBR. In terms of micropollutants, 7 out of 13 detected micropollutants were highly removed (efficiency higher than 85%) while 5 of them (ofloxacin, metoprolol acid, venlafaxine, iopromide and hydrochlorothiazide) were found to be highly recalcitrant to the treatment.}, } @article {pmid30965160, year = {2019}, author = {Jafari, M and Derlon, N and Desmond, P and van Loosdrecht, MCM and Morgenroth, E and Picioreanu, C}, title = {Biofilm compressibility in ultrafiltration: A relation between biofilm morphology, mechanics and hydraulic resistance.}, journal = {Water research}, volume = {157}, number = {}, pages = {335-345}, doi = {10.1016/j.watres.2019.03.073}, pmid = {30965160}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Filtration ; Membranes, Artificial ; *Ultrafiltration ; }, abstract = {Poroelastic fluid-structure interaction models were coupled to experimental data to determine the effects of biofilm spatial distribution of mechanical and hydraulic properties on the biofilm hydraulic resistance and compressibility in membrane filtration processes. Biofilms were cultivated on ultrafiltration membranes for 20 and 30 days under high (0.28 bar) and low (0.06 bar) transmembrane pressure (TMP), in dead-end filtration mode. Subsequently, biofilms were subjected to a compression/relaxation cycles by step-wise TMP changes. Structural deformation of biofilms during compression was observed in-situ using optical coherence tomography. Experimental results show that the observed increase in the biofilm hydraulic resistance during compression is not necessarily accompanied by a detectable biofilm thickness reduction. A dual-layer biofilm model with a dense base and porous top layer could explain these observed results. Because porosity controls indirectly the mechanical response of biofilms under compression, results could be described without assuming a gradient in mechanical properties within the biofilm. The biofilm surface roughness did not significantly influence the water flux in this study. However, the fraction of biofilm base layer directly exposed to bulk liquid could be a good indicator in the determination of water flux. The main implications of this study for the design and operation of low-pressure membrane systems (e.g., MF and UF with fouling layer being the main filtration resistance) lays in the selection of favorable operational TMP and biofilm morphology.}, } @article {pmid30965147, year = {2019}, author = {Aytac Bal, F and Ozkocak, I and Cadirci, BH and Sirin Karaarslan, E and Cakdinleyen, M and Agaccioglu, M}, title = {Effects of photodynamic therapy with indocyanine green on Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {229-234}, doi = {10.1016/j.pdpdt.2019.04.005}, pmid = {30965147}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Dental Caries/*drug therapy/*microbiology ; Disinfection/methods ; Humans ; In Vitro Techniques ; Indocyanine Green/*pharmacology ; Lasers, Semiconductor ; Molar ; Ozone/pharmacology ; Photochemotherapy/instrumentation/*methods ; Photosensitizing Agents/*pharmacology ; Sodium Hypochlorite/pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {BACKGROUND: The current procedures for treating tooth decay are not always guaranteed to successfully remove all microorganisms which cause disease. For elimination of bacteria and prevention of their effects, different methods are recommended, such as antibacterial materials and cavity disinfectants. The aim of this study was to compare the antibacterial activity of photodynamic therapy (PDT) using diode laser with indocyanin green (ICG) on Streptococcus (S.) mutans biofilm with conventional methods.

METHODS: Ninety human molars were divided into 9 groups: negative control, positive control, CHX, NaOCl, gaseous ozone, erbium (Er):YAG laser, diode laser, and indocyanin green/ICG, and PDT. Cavities were then cut into the teeth (2 per tooth, 20 cavities per group) and sterilized. For all of the groups, with the exception of the negative control group, 10[5] CFU/mL of the active S. mutans culture were inoculated into the cavities and then incubated at 37 °C for 72 h. Then, dentin chips (25 ± 5 mg) were collected from cavity walls and spread on Mueller-Hinton agar media after decimal dilution. The colonies were counted after incubation at 37 °C for 24 h.

RESULTS: All the treatments significantly reduced the number of S. mutans compared with the positive control group (p < 0.05). The antimicrobial effectiveness of CHX, NaOCl, ozone, PDT, Er:YAG laser, and diode laser groups were similar. The lowest bacterial reduction was observed in the ICGgroup.

CONCLUSIONS: This work concludes that PDT using diode laser with ICG may be suggested on the cavity disinfection after caries excavation as an alternative to conventional methods.}, } @article {pmid30965089, year = {2019}, author = {Souza Dos Santos, B and Bezerra Filho, CM and Alves do Nascimento Junior, JA and Brust, FR and Bezerra-Silva, PC and Lino da Rocha, SK and Krogfelt, KA and Maria do Amaral Ferraz Navarro, D and Tereza Dos Santos Correia, M and Napoleão, TH and Nascimento da Silva, LC and Macedo, AJ and Vanusa da Silva, M and Guedes Paiva, PM}, title = {Anti-staphylococcal activity of Syagrus coronata essential oil: Biofilm eradication and in vivo action on Galleria mellonela infection model.}, journal = {Microbial pathogenesis}, volume = {131}, number = {}, pages = {150-157}, doi = {10.1016/j.micpath.2019.04.009}, pmid = {30965089}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Arecaceae/*chemistry ; Biofilms/*drug effects/growth & development ; Brazil ; Disease Models, Animal ; Lepidoptera/*microbiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Oils, Volatile/chemistry/*pharmacology ; Plant Extracts/chemistry/*pharmacology ; Seeds/chemistry ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus/*drug effects ; Staphylococcus aureus/drug effects/growth & development ; }, abstract = {In this study, essential oil extracted from Syagrus coronata seeds (SCEO) was evaluated for antibacterial and antibiofilm activities against Staphylococcus aureus; in addition, Galleria mellonella model was used as an in vivo infection model. SCEO was mainly composed by fatty acids (89.79%) and sesquiterpenes (8.5%). The major components were octanoic acid, dodecanoic acid, decanoic acid and γ-eudesmol. SCEO showed bactericidal activity (minimal bactericidal concentration from 312 to 1250 μg/mL) against all tested S. aureus clinical isolates, which showed distinct biofilm-forming and multiple drug resistance phenotypes. SCEO weakly reduced biomass but remarkably decreased cell viability in pre-formed biofilms of S. aureus isolate UFPEDA-02 (ATCC-6538). Electron microscopy analysis showed that SCEO treatments decreased the number of bacterial cells (causing structural alterations) and lead to loss of the roughness in the multiple layers of the three-dimensional biofilm structure. In addition, overproduction of exopolymeric matrix was observed. SCEO at 31.2 mg/kg improved the survival of G. mellonela larvae inoculated with UFPEDA-02 isolate and reduced the bacterial load in hemolymph and melanization. In conclusion, SCEO is an antibacterial agent against S. aureus strains with different resistance phenotypes and able to disturb biofilm architecture. Our results show SCEO as a potential candidate to drug development.}, } @article {pmid30964013, year = {2018}, author = {Pattnaik, S and Barik, S and Muralitharan, G and Busi, S}, title = {Ferulic acid encapsulated chitosan-tripolyphosphate nanoparticles attenuate quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1.}, journal = {IET nanobiotechnology}, volume = {12}, number = {8}, pages = {1056-1061}, pmid = {30964013}, issn = {1751-875X}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/drug effects ; Chitosan/*analogs & derivatives/chemistry ; *Coumaric Acids/chemistry/pharmacology ; Drug Compounding ; Nanoparticles/*chemistry ; Particle Size ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; }, abstract = {Pseudomonas aeruginosa is an opportunistic nosocomial pathogenic microorganism causing majority of acute hospital-acquired infections and poses a serious public health concern. The persistence of bacterial infection can be attributed to the highly synchronised cell-to-cell communication phenomenon, quorum sensing (QS) which regulates the expression of a number of virulence factors and biofilm formation which eventually imparts resistance to the conventional antimicrobial therapy. In this study, the anti-quorum sensing and anti-biofilm potential of ferulic acid encapsulated chitosan-tripolyphosphate nanoparticles (FANPs) was investigated against P. aeruginosa PAO1 and compared with native ferulic acid. Dynamic light scattering and transmission electron microscopic analysis confirmed the synthesis of FANPs with mean diameter of 215.55 nm. FANPs showed significant anti-quorum sensing activity by downregulating QS-regulated virulence factors. In addition, FANPs also significantly attenuate the swimming and swarming motility of P. aeruginosa PAO1. The anti-biofilm efficacy of FANPs as compared to native ferulic acid was established by light and confocal laser scanning microscopic analysis. The promising results of FANPs in attenuating QS highlighted the slow and sustained release of ferulic acid at the target sites with greater efficacy suggesting its application towards the development of anti-infective agents.}, } @article {pmid30963965, year = {2020}, author = {Francolini, I and Piozzi, A}, title = {Role of Antioxidant Molecules and Polymers in Prevention of Bacterial Growth and Biofilm Formation.}, journal = {Current medicinal chemistry}, volume = {27}, number = {29}, pages = {4882-4904}, doi = {10.2174/0929867326666190409120409}, pmid = {30963965}, issn = {1875-533X}, mesh = {Anti-Bacterial Agents ; *Antioxidants ; *Biofilms ; Flavonoids ; Microbial Sensitivity Tests ; *Polymers ; Polyphenols ; }, abstract = {BACKGROUND: Antioxidants are multifaceted molecules playing a crucial role in several cellular functions. There is by now a well-established knowledge about their involvement in numerous processes associated with aging, including vascular damage, neurodegenerative diseases and cancer. An emerging area of application has been lately identified for these compounds in relation to the recent findings indicating their ability to affect biofilm formation by some microbial pathogens, including Staphylococcus aureus, Streptococcus mutans, and Pseudomonas aeruginosa.

METHODS: A structured search of bibliographic databases for peer-reviewed research literature was performed using a focused review question. The quality of retrieved papers was appraised using standard tools.

RESULTS: One hundred sixty-five papers extracted from pubmed database and published in the last fifteen years were included in this review focused on the assessment of the antimicrobial and antibiofilm activity of antioxidant compounds, including vitamins, flavonoids, non-flavonoid polyphenols, and antioxidant polymers. Mechanisms of action of some important antioxidant compounds, especially for vitamin C and phenolic acids, were identified.

CONCLUSIONS: The findings of this review confirm the potential benefits of the use of natural antioxidants as antimicrobial/antibiofilm compounds. Generally, gram-positive bacteria were found to be more sensitive to antioxidants than gram-negatives. Antioxidant polymeric systems have also been developed mainly derived from functionalization of polysaccharides with antioxidant molecules. The application of such systems in clinics may permit to overcome some issues related to the systemic delivery of antioxidants, such as poor absorption, loss of bioactivity, and limited half-life. However, investigations focused on the study of antibiofilm activity of antioxidant polymers are still very limited in number and therefore they are strongly encouraged in order to lay the foundations for application of antioxidant polymers in treatment of biofilm-based infections.}, } @article {pmid30962840, year = {2019}, author = {Naumenko, ZS and Silanteva, TA and Ermakov, AM and Godovykh, NV and Klushin, NM}, title = {Challenging Diagnostics of Biofilm Associated Periprosthetic Infection in Immunocompromised Patient: A Clinical Case.}, journal = {Open access Macedonian journal of medical sciences}, volume = {7}, number = {5}, pages = {786-790}, pmid = {30962840}, issn = {1857-9655}, abstract = {BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication of joint arthroplasty. The identification of microorganisms in biofilm-related PJI is challenging yet significant stage of the treatment process. Medical microbiology methods, such as pure culture isolation, remain the gold standard. However, the error rate of classical methods may vary from 10% to as high as 42% due to the inability to detect bacteria growing within biofilms. Other methods of detection are being explored to improve the management of PJI.

AIM: Accurate identification of PJI contributing microorganisms in a patient with acute postoperative PJI after total hip joint arthroplasty and systemic lupus erythematosus in anamnesis.

METHODS: We used microbial culture methods followed by scanning electron microscopy (SEM).

RESULTS: Perioperative an intraoperative cultural analysis of 8 different culture samples of tissue and prosthetic origin was insufficient for bacterial or fungal detection. Scanning electron microscopy revealed detailed biofilm visualisation on the surface of the prosthetic component. The biofilm exterior was composed of microbial clusters made of 10 or more cells with either pear- or bottle-shaped morphology, 3-6 mcm in length and 1.5-3 mcm in diameter. Rod-shaped microorganisms of 0.7-1 mcm length and up to 0.5 mcm in diameter were found adjacent to these clusters.

CONCLUSION: Additional methods for PJI agents' detection are time-and cost-effective in the case of the challenging diagnostics of biofilm-related PJI, particularly in immunocompromised patients. Using combined diagnostic approaches increases the accuracy of detection, justifies treatment strategies and improves clinical outcomes.}, } @article {pmid30962351, year = {2019}, author = {Neiger, MR and González, JF and Gonzalez-Escobedo, G and Kuck, H and White, P and Gunn, JS}, title = {Pathoadaptive Alteration of Salmonella Biofilm Formation in Response to the Gallbladder Environment.}, journal = {Journal of bacteriology}, volume = {201}, number = {14}, pages = {}, pmid = {30962351}, issn = {1098-5530}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; R56 AI109002/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cholesterol/metabolism ; Gallbladder/*microbiology ; Gallstones/microbiology ; *Gene Expression Regulation, Bacterial ; Mice ; Mice, 129 Strain ; Polymorphism, Single Nucleotide ; Salmonella typhi/*genetics/*pathogenicity ; Virulence ; }, abstract = {Typhoid fever, a human-specific disease, is primarily caused by the pathogen Salmonella enterica serovar Typhi. It is estimated that 3 to 5% of people infected with typhoid fever become chronic carriers. Studies have demonstrated that a mechanism of chronic carriage involves biofilm formation on gallstone surfaces. In the course of a previous study using a chronic carriage mouse model, a Salmonella enterica serovar Typhimurium isolate was recovered from a mouse gallstone that exhibited a 2-fold increase in biofilm formation over the wild type. In order to identify the gene(s) responsible for the phenotype, the genomic sequences of this isolate and others were determined and compared. These sequences identified single nucleotide polymorphisms (SNPs) in 14 genes. Mutations in the most promising candidates, envZ and rcsB, were created, but neither showed increased biofilm-forming ability separately or in combination. The hyperbiofilm isolate did, however, present variations in cellular appendages observable using different techniques and a preferential binding to cholesterol. The isolate was also examined for systemic virulence and the ability to colonize the gallbladder/gallstones in a mouse model of chronic infection, demonstrating a systemic virulence defect and decreased gallbladder/gallstone colonization. Finally, to determine if the appearance of hyperbiofilm isolates could be replicated in vitro and if this was a common event, wild-type Salmonella spp. were grown long term in vitro under gallbladder-mimicking conditions, resulting in a high proportion of isolates that replicated the hyperbiofilm phenotype of the original isolate. Thus, Salmonella spp. acquire random mutations under the gallbladder/gallbladder-simulating conditions that may aid persistence but negatively affect systemic virulence.IMPORTANCE Chronic carriers are the main reservoirs for the spread of typhoid fever in regions of endemicity. Salmonella Typhi forms biofilms on gallstones in order to persist. A strain with enhanced biofilm-forming ability was recovered after a nine-month chronic-carriage mouse study. After sequencing this strain and recreating some of the mutations, we could not duplicate the phenotype. The isolate did show a difference in flagella, a preference to bind to cholesterol, and a systemic virulence defect. Finally, gallbladder conditions were simulated in vitro After 60 days, there was a 4.5-fold increase in hyperbiofilm isolates when a gallstone was present. These results indicate that Salmonella spp. can undergo genetic changes that improve persistence in gallbladder albeit at the cost of decreased virulence.}, } @article {pmid30961703, year = {2019}, author = {Lu, R and Sun, J and Osei-Adjei, G and Zhang, Y and Huang, X}, title = {The Periplasmic Chaperone SurA Affects Motility and Biofilm Formation via the RcsCDB Pathway in Salmonella enterica Serovar Typhi.}, journal = {Journal of nanoscience and nanotechnology}, volume = {19}, number = {9}, pages = {5503-5509}, doi = {10.1166/jnn.2019.16503}, pmid = {30961703}, issn = {1533-4880}, mesh = {Bacterial Proteins/genetics ; Biofilms ; *Gene Expression Regulation, Bacterial/genetics ; Salmonella ; *Salmonella typhi/genetics ; Virulence ; }, abstract = {SurA, a periplasmic chaperone, is a key factor in the biogenesis of β-barrel outer membrane proteins (OMPs). It is also associated with virulence, invasion and biofilm formation in Escherichia and Salmonella species. To investigate whether SurA affects bacterial motility and biofilm formation in Salmonella enterica serovar Typhi, we prepared a surA deleted mutant. Motility assay and quantitative real-time PCR (qRT-PCR) indicated that surA deletion reduced swimming motility and decreased flagellar gene expression, respectively. β-galactosidase assay and qRT-PCR further showed that surA deletion also activated the RcsCDB pathway, which we verified affected motility. We also examined the effects of the surA deletion on biofilm formation and established that the surA mutant exhibited significantly reduced ability to form biofilms compared with the wild-type. From our findings, we proposed that the periplasmic chaperone, SurA, affects flagella expression via the RcsCDB pathway thereby influencing biofilm formation in Salmonella enterica serovar Typhi. Collectively, these studies confirmed a new physiological role for SurA in Salmonella enterica serovar Typhi.}, } @article {pmid30960145, year = {2019}, author = {Lang, Y and Sun, Y and Yu, M and Ji, Y and Wang, L and Zhang, Z}, title = {Differential Colonization Dynamics of Marine Biofilm-Forming Eukaryotic Microbes on Different Protective Coating Materials.}, journal = {Polymers}, volume = {11}, number = {1}, pages = {}, pmid = {30960145}, issn = {2073-4360}, support = {2017M621294//Chinese Postdoctoral Science Foundation/ ; 41418083//the Fundamental Operating Expenses of the Central Universities/ ; 2017BSH002,2017BSH003//the Supporting Program of the Postdoctoral Research at the Harbin University of Commerce/ ; 17XN011, 17XN010//the Training Program of the Young Creative Talents at the Harbin University of Commerce/ ; 2016GSF115022//the Key research and development plan of Shandong Province/ ; ZR2018MC002//the Natural Science Foundation of Shandong Province/ ; UNPYSCT-2018139//Innovative Talent Project of Ministry of Education, Heilongjiang Province/ ; YJSCX2018-484HSD//Innovative Research Project of Graduate Students at Harbin university of commerce/ ; }, abstract = {In this study, the actual anti-biofouling (AF) efficacy of three protective coatings, including a chlorinated rubber-based coating (C0) and two polydimethylsiloxane (PDMS)-based coatings (P0 and PF), were estimated via the static field exposure assays. The surface properties of these protective coatings, including surface wettability and morphology features, were characterized using the static water contact angle (WCA) and scanning electron microscope (SEM). The colonization and succession dynamics of the early-adherent biofilm-forming eukaryotic microbial communities occupied on these protective coatings were explored using the Single-stranded Conformation Polymorphism (SSCP) technique. The field data clearly revealed that coating P0 and PF performed better in the long-term static submergence, as compared with the C0 surface, while coating PF showed excellent AF efficacy in the field. Fingerprinting analysis suggested that the diversity, abundance, the clustering patterns, and colonization dynamics of the early-colonized eukaryotic microbes were significantly perturbed by these protective coatings, particularly by the PF surfaces. These differential AF efficacy and perturbation effects would be largely ascribed to the differences in the wettability and surface nanostructures between the C0, P0 and PF surfaces, as evidenced by WCA and SEM analysis.}, } @article {pmid30959988, year = {2018}, author = {Othman, M and Rashid, H and Jamal, NA and Shaharuddin, SIS and Sulaiman, S and Hairil, HS and Khalid, K and Zakaria, MN}, title = {Effect of Cinnamon Extraction Oil (CEO) for Algae Biofilm Shelf-Life Prolongation.}, journal = {Polymers}, volume = {11}, number = {1}, pages = {}, pmid = {30959988}, issn = {2073-4360}, abstract = {This study was conducted to improve the life-span of the biofilm produced from algae by evaluating the decomposition rate with the effect of cinnamon extraction oil (CEO). The biofilm was fabricated using the solution casting technique. The soil burying analysis demonstrated low moisture absorption of the biofilm, thus decelerating the degradation due to low swelling rate and micro-organism activity, prolonging the shelf-life of the biofilm. Hence, the addition of CEO also affects the strength properties of the biofilm. The maximum tensile strength was achieved with the addition of 5% CEO, which indicated a good intermolecular interaction between the biopolymer (algae) and cinnamon molecules. The tensile strength, which was measured at 4.80 MPa, correlated with the morphological structure. The latter was performed using SEM, where the surface showed the absence of a separating phase between the biofilm and cinnamon blend. This was evidenced by FTIR analysis, which confirmed the occurrence of no chemical reaction between the biofilm and CEO during processing. The prolongation shelf-life rate of biofilm with good tensile properties are achievable with the addition of 5% of CEO.}, } @article {pmid30959097, year = {2019}, author = {Hnamte, S and Parasuraman, P and Ranganathan, S and Ampasala, DR and Reddy, D and Kumavath, RN and Suchiang, K and Mohanty, SK and Busi, S}, title = {Mosloflavone attenuates the quorum sensing controlled virulence phenotypes and biofilm formation in Pseudomonas aeruginosa PAO1: In vitro, in vivo and in silico approach.}, journal = {Microbial pathogenesis}, volume = {131}, number = {}, pages = {128-134}, doi = {10.1016/j.micpath.2019.04.005}, pmid = {30959097}, issn = {1096-1208}, mesh = {Alginates ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Caenorhabditis elegans ; Chitinases/metabolism ; Disease Models, Animal ; Flavonoids/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Glycolipids/metabolism ; Hydrophobic and Hydrophilic Interactions ; Metalloendopeptidases/genetics ; Microbial Sensitivity Tests ; *Phenotype ; Pseudomonas aeruginosa/*drug effects/genetics ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects ; Trans-Activators/genetics ; Virulence/drug effects/genetics ; Virulence Factors/genetics ; }, abstract = {Quorum sensing (QS) is the cell density dependent communication network which coordinates the production of pathogenic determinants in majority of pathogenic bacteria. Pseudomonas aeruginosa causes hospital-acquired infections by virtue of its well-defined QS network. As the QS regulatory network in P. aeruginosa regulates the virulence determinants and antibiotic resistance, attenuating the QS system seems to be influential in developing next-generation anti-infective agents. In the current study, the QS attenuation potential of a flavonoid, mosloflavone was investigated against P. aeruginosa virulence and biofilm formation. Mosloflavone inhibited the pyocyanin production, LasB elastase and chitinase by 59.52 ± 2.74, 35.90 ± 4.34 and 61.18 ± 5.52% respectively. The QS regulated biofilm formation and development was also reduced when supplemented with sub-MIC of mosloflavone. The gene expression studies of mosloflavone using RT-PCR depicted its ability to down-regulate the expression levels of QS regulated virulence genes such as lasI (60.64%), lasR (91.70%), rhlI (57.30%), chiC (90.20%), rhlA (47.87%), rhlR (21.55%), lasB (37.80%), phzM (42.40%), toxA (61.00%), aprA (58.4%), exoS (78.01%), algD (46.60%) and pelA (50.45%). The down-regulation of QS virulence phenotypes by mosloflavone could be attributed to its binding affinity with the QS regulatory proteins, LasR and RhlR by competitively inhibiting the binding of natural autoinducers as evidenced from simulation studies. Mosloflavone also exhibited promising potential in controlling bacterial infection in Caenorhabditis elegans model system, in vivo. The anti-biofilm and anti-QS potential of mosloflavone in the current study illustrated the candidature of mosloflavone as a promising biocide.}, } @article {pmid30958690, year = {2019}, author = {Yin, L and Li, Q and Xue, M and Wang, Z and Tu, J and Song, X and Shao, Y and Han, X and Xue, T and Liu, H and Qi, K}, title = {The role of the phoP transcriptional regulator on biofilm formation of avian pathogenic Escherichia coli.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {48}, number = {4}, pages = {362-370}, doi = {10.1080/03079457.2019.1605147}, pmid = {30958690}, issn = {1465-3338}, mesh = {Agglutination ; Animals ; Biofilms/*growth & development ; Chickens/*microbiology ; Drug Resistance, Multiple ; Escherichia coli/genetics/pathogenicity/*physiology ; Escherichia coli Infections/microbiology/*veterinary ; Escherichia coli Proteins/*physiology ; Gene Knockout Techniques/veterinary ; Hydrophobic and Hydrophilic Interactions ; Mutation ; Oligonucleotide Array Sequence Analysis/veterinary ; Poultry Diseases/*microbiology ; RNA, Bacterial/isolation & purification ; Real-Time Polymerase Chain Reaction/veterinary ; }, abstract = {PhoP plays an important role as a transcriptional regulator in the two-component phoP/phoQ regulatory system, which is widely present in Gram-negative bacteria. In this study, we used DNA microarray-based technology to evaluate the role of phoP in biofilm formation in avian pathogenic Escherichia coli (APEC). Differences in gene transcription between APEC wild-type and phoP mutant strains were determined. Mutation of the phoP transcriptional regulator affects the expression profile of genes involved in processes such as flagellar assembly, ABC transporters, quorum sensing, and bacterial chemotaxis. Deletion of phoP in APEC reduced biofilm formation, as indicated by crystal violet staining and scanning electron microscopy (SEM). In addition, the phoP gene was found to be associated with changes in bacterial drug resistance and cell-membrane-related properties. This study shows that phoP plays an important regulatory role in APEC biofilm formation, and provides new insights into strategies for preventing and controlling APEC infection.}, } @article {pmid30956871, year = {2019}, author = {Kim, H and Moon, MJ and Kim, CY and Ryu, K}, title = {Efficacy of chemical sanitizers against Bacillus cereus on food contact surfaces with scratch and biofilm.}, journal = {Food science and biotechnology}, volume = {28}, number = {2}, pages = {581-590}, pmid = {30956871}, issn = {2092-6456}, abstract = {This study was performed to investigate the efficacy of chemical sanitizers (viz., chlorine, chlorine dioxide, alcohol, and quaternary ammonium compound) against Bacillus cereus on five food contact materials under different conditions (smooth vs. scratched and with vs. without biofilms). After incubating materials in B. cereus suspension, cell adhesion on a smooth surface (10 cm[2]) was in the following ascending order: stainless steel (7.36 ± 0.08 log CFU), glass (7.51 ± 0.26 log CFU), polyethylene (7.66 ± 0.30 log CFU), polypropylene (7.76 ± 0.30 log CFU), and wood (8.02 ± 0.33 log CFU). The efficacy of sanitizers was dramatically reduced in the presence of a biofilm on all materials. Among four different chemical sanitizers, chlorine showed the best bactericidal activity against B. cereus on the surface with scratch and biofilm. Selection of adequate materials, maintenance of a smooth surface, and inhibition of biofilm formation are good practices for food safety.}, } @article {pmid30956641, year = {2019}, author = {Awan, AB and Schiebel, J and Böhm, A and Nitschke, J and Sarwar, Y and Schierack, P and Ali, A}, title = {Association of biofilm formation and cytotoxic potential with multidrug resistance in clinical isolates of Pseudomonas aeruginosa.}, journal = {EXCLI journal}, volume = {18}, number = {}, pages = {79-90}, pmid = {30956641}, issn = {1611-2156}, abstract = {Multidrug resistant (MDR) Pseudomonas aeruginosa having strong biofilm potential and virulence factors are a serious threat for hospitalized patients having compromised immunity. In this study, 34 P. aeruginosa isolates of human origin (17 MDR and 17 non-MDR clinical isolates) were checked for biofilm formation potential in enriched and minimal media. The biofilms were detected using crystal violet method and a modified software package of the automated VideoScan screening method. Cytotoxic potential of the isolates was also investigated on HepG2, LoVo and T24 cell lines using automated VideoScan technology. Pulse field gel electrophoresis revealed 10 PFGE types in MDR and 8 in non-MDR isolates. Although all isolates showed biofilm formation potential, strong biofilm formation was found more in enriched media than in minimal media. Eight MDR isolates showed strong biofilm potential in both enriched and minimal media by both detection methods. Strong direct correlation between crystal violet and VideoScan methods was observed in identifying strong biofilm forming isolates. High cytotoxic effect was observed by 4 isolates in all cell lines used while 6 other isolates showed high cytotoxic effect on T24 cell line only. Strong association of multidrug resistance was found with biofilm formation as strong biofilms were observed significantly higher in MDR isolates (p-value < 0.05) than non-MDR isolates. No significant association of cytotoxic potential with multidrug resistance or biofilm formation was found (p-value > 0.05). The MDR isolates showing significant cytotoxic effects and strong biofilm formation impose a serious threat for hospitalized patients with weak immune system.}, } @article {pmid30955967, year = {2020}, author = {Qu, Y and McGiffin, D and Kure, C and Ozcelik, B and Fraser, J and Thissen, H and Peleg, AY}, title = {Biofilm formation and migration on ventricular assist device drivelines.}, journal = {The Journal of thoracic and cardiovascular surgery}, volume = {159}, number = {2}, pages = {491-502.e2}, doi = {10.1016/j.jtcvs.2019.02.088}, pmid = {30955967}, issn = {1097-685X}, mesh = {*Biofilms ; Candida albicans/pathogenicity/physiology ; Candidiasis/microbiology ; Cell Movement ; Heart-Assist Devices/*microbiology ; Humans ; Prosthesis-Related Infections/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/pathogenicity/physiology ; Staphylococcus epidermidis/pathogenicity/physiology ; }, abstract = {OBJECTIVES: Driveline infections remain an important complication of ventricular assist device therapy, with biofilm formation being a major contributor. This study aimed to elucidate factors that govern biofilm formation and migration on clinically relevant ventricular assist device drivelines.

METHODS: Experimental analyses were performed on HeartWare HVAD (HeartWare International Inc, Framingham, Mass) drivelines to assess surface chemistry and biofilm formation. To mimic the driveline exit site, a drip-flow biofilm reactor assay was used. To mimic a subcutaneous tissue environment, a tunnel-based interstitial biofilm assay was developed. Clinical HVAD drivelines explanted at the time of cardiac transplantation were also examined by scanning electron microscopy.

RESULTS: Common causative pathogens of driveline infections were able to adhere to the smooth and velour sections of the HVAD driveline and formed robust biofilms in the drip-flow biofilm reactor; however, Pseudomonas aeruginosa and Candida albicans had greater biomass. Biofilm migration within the interstitial driveline tunnel was evident for Staphylococcus epidermidis, Staphylococcus aureus, and C albicans, but not P aeruginosa. Biofilm formation by staphylococci was 500 to 10,000 times higher in the tunnel-based model compared with our exit site model. The 3-dimensional structure of the driveline velour and the use of silicone adhesive in driveline manufacturing were found to promote biofilm growth, and explanted patient drivelines demonstrated inadequate tissue in-growth along the entire velour with micro-gaps between velour fibers.

CONCLUSIONS: This work highlights the predilection of pathogens to different parts of the driveline, the importance of the subcutaneous tunnel to biofilm formation and migration, and the presence of micro-gaps in clinical drivelines that could facilitate invasive driveline infections.}, } @article {pmid30954574, year = {2019}, author = {Le, KY and Villaruz, AE and Zheng, Y and He, L and Fisher, EL and Nguyen, TH and Ho, TV and Yeh, AJ and Joo, HS and Cheung, GYC and Otto, M}, title = {Role of Phenol-Soluble Modulins in Staphylococcus epidermidis Biofilm Formation and Infection of Indwelling Medical Devices.}, journal = {Journal of molecular biology}, volume = {431}, number = {16}, pages = {3015-3027}, doi = {10.1016/j.jmb.2019.03.030}, pmid = {30954574}, issn = {1089-8638}, support = {ZIA AI000904/ImNIH/Intramural NIH HHS/United States ; }, mesh = {Animals ; Bacterial Toxins/genetics/*metabolism ; Biofilms/*growth & development ; Catheter-Related Infections/*microbiology ; Catheters, Indwelling/microbiology ; Colony Count, Microbial ; Disease Models, Animal ; Humans ; Mice ; Sequence Deletion ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/growth & development/metabolism/*pathogenicity ; }, abstract = {Phenol-soluble modulins (PSMs) are amphipathic, alpha-helical peptides that are secreted by staphylococci in high amounts in a quorum-sensing-controlled fashion. Studies performed predominantly in Staphylococcus aureus showed that PSMs structure biofilms, which results in reduced biofilm mass, while it has also been reported that S. aureus PSMs stabilize biofilms due to amyloid formation. We here analyzed the roles of PSMs in in vitro and in vivo biofilms of Staphylococcus epidermidis, the leading cause of indwelling device-associated biofilm infection. We produced isogenic deletion mutants for every S. epidermidis psm locus and a sequential deletion mutant in which production of all PSMs was abolished. In vitro analysis substantiated the role of all PSMs in biofilm structuring. PSM-dependent biofilm expansion was not observed, in accordance with our finding that no S. epidermidis PSM produced amyloids. In a mouse model of indwelling device-associated infection, the total psm deletion mutant had a significant defect in dissemination. Notably, the total psm mutant produced a significantly more substantial biofilm on the implanted catheter than the wild-type strain. Our study, which for the first time directly quantified the impact of PSMs on biofilm expansion on an implanted device, shows that the in vivo biofilm infection phenotype in S. epidermidis is in accordance with the PSM biofilm structuring and detachment model, which has important implications for the potential therapeutic application of quorum-sensing blockers.}, } @article {pmid30953857, year = {2019}, author = {Zan, F and Liang, Z and Jiang, F and Dai, J and Chen, G}, title = {Effects of food waste addition on biofilm formation and sulfide production in a gravity sewer.}, journal = {Water research}, volume = {157}, number = {}, pages = {74-82}, doi = {10.1016/j.watres.2019.03.061}, pmid = {30953857}, issn = {1879-2448}, mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; Food ; Food Additives ; *Hydrogen Sulfide ; *Refuse Disposal ; Sewage ; Sulfides ; Waste Disposal, Fluid ; }, abstract = {The conversion of food waste (FW) into the sewage system is regarded as a promising method of relieving the burden of solid waste management. However, knowledge about its effects on sewer processes is limited, particularly in terms of biofilm formation and sulfide production. In this study, a gravity sewer system was set up to investigate the effects of the addition of FW on biofilm formation, the sulfate-reducing bacteria (SRB) population, and the sulfide production potential. The sewer biofilm characteristics changed with long-term FW addition, and a greater thickness (by 32%), an increased dry density (by 13%), and more extracellular polymeric substance (by 141%) were observed. The thicker and denser biofilm limited oxygen diffusion, enlarged the anaerobic area in the sewer biofilm, promoted an increase in the SRB population, and enhanced the sulfide production potential in the gravity sewer. Substantial differences in the H2S profiles in the biofilm samples with and without the addition of FW were observed via microelectrode analysis. A model-based investigation of sewer biofilm formation with and without the addition of FW was conducted with a dynamic sewer biofilm model to gain further insights into sewer biofilm processes. The results suggest that the addition of FW can promote sulfide production and SRB growth in a sewer biofilm, which can be significantly affected by the ratio of FW to sewage. It is worth further investigations of the impacts of FW addition on the potential sulfide production in pressure sewers.}, } @article {pmid30953693, year = {2019}, author = {Kim, HR and Rhee, KJ and Eom, YB}, title = {Anti-biofilm and antimicrobial effects of zerumbone against Bacteroides fragilis.}, journal = {Anaerobe}, volume = {57}, number = {}, pages = {99-106}, doi = {10.1016/j.anaerobe.2019.04.001}, pmid = {30953693}, issn = {1095-8274}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacteroides fragilis/*drug effects ; Biofilms/*drug effects ; Enzyme Inhibitors/isolation & purification/pharmacology ; Gene Expression Profiling ; Membrane Transport Proteins/analysis ; Microbial Sensitivity Tests ; Plant Extracts/isolation & purification/pharmacology ; Sesquiterpenes/isolation & purification/*pharmacology ; Zingiberaceae/chemistry ; }, abstract = {Enterotoxigenic Bacteroides fragilis (ETBF) can form biofilms in the colon mucosal membrane and may promote chronic infection and tumor formation. The objective of this study was to determine the effect of zerumbone extracted from Zingiber zerumbet (L.) Smith, on B. fragilis biofilm formation. Inhibitory effects of zerumbone on planktonic cell growth and biofilm formation were examined by crystal-violet biofilm assays and XTT metabolic assays. Results showed that zerumbone significantly inhibited biofilm formation and eradicated established biofilms. Furthermore, B. fragilis biofilms inhibited by zerumbone were observed by confocal laser scanning microscopy. qRT-PCR was used to support the phenotypic results and to investigate the expression levels of an efflux pump-related gene (bmeB). Specifically, among the efflux pump-related genes, zerumbone significantly suppressed the expression level of bmeB12. These results indicate that zerumbone might be a promising candidate as an anti-biofilm and antimicrobial agent to treat and prevent biofilm-related infections caused by B. fragilis.}, } @article {pmid30953691, year = {2019}, author = {Di Somma, A and Caterino, M and Soni, V and Agarwal, M and di Pasquale, P and Zanetti, S and Molicotti, P and Cannas, S and Nandicoori, VK and Duilio, A}, title = {The bifunctional protein GlmU is a key factor in biofilm formation induced by alkylating stress in Mycobacterium smegmatis.}, journal = {Research in microbiology}, volume = {170}, number = {4-5}, pages = {171-181}, doi = {10.1016/j.resmic.2019.03.002}, pmid = {30953691}, issn = {1769-7123}, mesh = {Acetyltransferases/antagonists & inhibitors/genetics/*metabolism ; Alkylation ; Bacterial Proteins/antagonists & inhibitors/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Profiling ; Methyl Methanesulfonate/*pharmacology ; Multienzyme Complexes/antagonists & inhibitors/genetics/*metabolism ; Mycobacterium smegmatis/enzymology/genetics/*growth & development ; Mycobacterium tuberculosis/enzymology/genetics/*growth & development ; N-Acetylneuraminic Acid/metabolism ; Nucleotidyltransferases/antagonists & inhibitors/genetics/metabolism ; }, abstract = {Living organisms have developed specific defence mechanisms to counteract hostile environmental conditions. Alkylation stress response mechanisms also occur in Mycobacterium tuberculosis (MTB) the pathogen responsible for tuberculosis. The effect of alkylating agents on the cellular growth of MTB was investigated using methyl methanesulfonate (MMS) as methyl donor demonstrating that limited doses of alkylating agents might affect MTB cell viability. A global investigation of Mycobacterium smegmatis response to alkylating stress was then pursued by differential proteomics to identify the most affected cellular pathways. Quantitative analysis of proteomic profiles demonstrated that most of the proteins upregulated in the presence of alkylating agents are involved in biofilm formation and/or cell wall biosynthesis. Tailored experiments confirmed that under stress conditions M. smegmatis elicits physical defence mechanisms by increasing biofilm formation. Among the upregulated proteins, we identified the GlmU bifunctional enzyme as a possible factor involved in biofilm production. Experiments with both conditional deletion and overexpressing glmU mutants demonstrated that down regulation of GlmU decreased M. smegmatis capabilities to produce biofilm whereas overexpression of the enzyme increased biofilm formation. These results were supported by inhibition of GlmU acetyltransferase activity with two different inhibitors, suggesting the involvement of this enzyme in the M. smegmatis defence mechanisms.}, } @article {pmid30953053, year = {2020}, author = {Walker, JN and Pinkner, CL and Lynch, AJL and Ortbal, S and Pinkner, JS and Hultgren, SJ and Myckatyn, TM}, title = {Deposition of Host Matrix Proteins on Breast Implant Surfaces Facilitates Staphylococcus Epidermidis Biofilm Formation: In Vitro Analysis.}, journal = {Aesthetic surgery journal}, volume = {40}, number = {3}, pages = {281-295}, doi = {10.1093/asj/sjz099}, pmid = {30953053}, issn = {1527-330X}, mesh = {Anti-Bacterial Agents ; Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; Humans ; Staphylococcus epidermidis ; }, abstract = {BACKGROUND: Staphylococcus epidermidis is a primary cause of breast implant-associated infection. S epidermidis possesses several virulence factors that enable it to bind both abiotic surfaces and host factors to form a biofilm. In addition S epidermidis colocalizes with matrix proteins coating explanted human breast implants.

OBJECTIVES: The authors sought to identify matrix proteins that S epidermidis may exploit to infect various breast implant surfaces in vitro.

METHODS: A combination of in vitro assays was used to characterize S epidermidis strains isolated from human breast implants to gain a better understanding of how these bacteria colonize breast implant surfaces. These included determining the (1) minimum inhibitory and bactericidal concentrations for irrigation solutions commonly used to prevent breast implant contamination; (2) expression and carriage of polysaccharide intercellular adhesin and serine-aspartate repeat proteins, which bind fibrinogen (SdrG) and collagen (SdrF), respectively; and (3) biofilm formation on varying implant surface characteristics, in different growth media, and supplemented with fibrinogen and Types I and III collagen. Scanning electron microscopy and immunofluorescence staining analyses were performed to corroborate findings from these assays.

RESULTS: Textured breast implant surfaces support greater bacterial biofilm formation at baseline, and the addition of collagen significantly increases biomass on all surfaces tested. We found that S epidermidis isolated from breast implants all encoded SdrF. Consistent with this finding, these strains had a clear affinity for Type I collagen, forming dense, highly structured biofilms in its presence.

CONCLUSIONS: The authors found that S epidermidis may utilize SdrF to interact with Type I collagen to form biofilm on breast implant surfaces.}, } @article {pmid30951891, year = {2019}, author = {Philip, N and Bandara, HMHN and Leishman, SJ and Walsh, LJ}, title = {Effect of polyphenol-rich cranberry extracts on cariogenic biofilm properties and microbial composition of polymicrobial biofilms.}, journal = {Archives of oral biology}, volume = {102}, number = {}, pages = {1-6}, doi = {10.1016/j.archoralbio.2019.03.026}, pmid = {30951891}, issn = {1879-1506}, mesh = {*Biofilms ; *Dental Caries ; Humans ; Plant Extracts ; Polyphenols ; Streptococcus mutans ; *Vaccinium macrocarpon ; }, abstract = {OBJECTIVE: To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria.

METHODS: Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated for 2 min every 12 h over the entire biofilm growth period with 500 μg/mL cranberry extract or vehicle control. The effect of the cranberry extract on biofilm behaviour was evaluated using different assays and its influence on key cariogenic and health-associated bacterial populations was assessed with a microarray real-time quantitative PCR method.

RESULTS: Cranberry-treated biofilms showed significant drops in biomass (38% reduction, P <  0.001), acidogenicity (44% reduction, P <  0.001), EPS/microbial biovolume ratios (P =  0.033), and CFU counts (51% reduction, P =  0.001). Furthermore, the cranberry extracts effected a significantly lower relative abundance of caries-associated Streptococcus sobrinus (fold change 0.004, P =  0.002) and Provotella denticola (0.002, P <  0.001), and a significantly higher relative abundance of the health-associated Streptococcus sanguinis (fold change 90.715, P =  0.001).

CONCLUSIONS: The cranberry extract lowered biofilm biomass, acidogenicity, EPS/microbial biovolumes, CFU counts, and modulated a beneficial microbial ecological change in saliva-derived polymicrobial biofilms.}, } @article {pmid30951818, year = {2019}, author = {Chen, X and Li, P and Shen, Y and Zou, Y and Yuan, G and Hu, H}, title = {Rhamnolipid-involved antibiotics combinations improve the eradication of Helicobacter pylori biofilm in vitro: A comparison with conventional triple therapy.}, journal = {Microbial pathogenesis}, volume = {131}, number = {}, pages = {112-119}, doi = {10.1016/j.micpath.2019.04.001}, pmid = {30951818}, issn = {1096-1208}, mesh = {Amoxicillin/pharmacology ; Biofilms/*drug effects/growth & development ; Clarithromycin/pharmacology ; Drug Resistance, Bacterial ; Drug Synergism ; Drug Therapy, Combination ; Glycolipids/*pharmacology ; Helicobacter pylori/*drug effects/growth & development ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Proton Pump Inhibitors/pharmacology ; }, abstract = {Antibiotics resistance of H. pylori has been increasing constantly accompanied with decreasing clearance rate clinically, which is demonstrated to be closely related to biofilms with higher resistance than planktonic bacteria for the dense extracellular polymeric substances. Rhamnolipid (RHL) is proved to not only damage the structure of biofilm, but also potentially inhibit bacterial adhesion. To investigate if RHL could promote eradicating rate of the conventional triple therapy to H. pylori biofilm and hence attenuate the resistance and relapse of H. pylori, first-line antibiotics clarithromycin (CLR), amoxicillin (AMX) or/and proton pump inhibitor (PPI) involved single, dual or triple therapies were compared with RHL-containing drug combinations on eradicating H. pylori biofilm. The residual biofilm biomass, the survival of bacteria inside the remaining biofilm and the planktonic bacteria dispersed from the biofilm after treatment were tested. Combination with RHL significantly improved the ability of antibiotics to eradicate H. pylori biofilm, especially RHL combined with AMX and PPI could eradicate more than 95% of biofilm showing much more effective ability than the conventional triple therapy CLR + AMX + PPI. Additionally, the combination of RHL and antibiotics could effectively inhibit the biofilm formation at lower concentration. Thus, RHL might be used as a potential antibiotic adjuvant on anti-H. pylori therapy to enhance eradicating ability of antibiotics to biofilms.}, } @article {pmid30951240, year = {2019}, author = {Mahapa, A and Samanta, GC and Maiti, K and Chatterji, D and Jayaraman, N}, title = {Mannopyranoside Glycolipids Inhibit Mycobacterial and Biofilm Growth and Potentiate Isoniazid Inhibition Activities in M. smegmatis.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {20}, number = {15}, pages = {1966-1976}, doi = {10.1002/cbic.201900040}, pmid = {30951240}, issn = {1439-7633}, mesh = {Biofilms/*drug effects/growth & development ; Glycolipids/chemical synthesis/chemistry/*pharmacology ; Lipopolysaccharides/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Mycobacterium smegmatis/*drug effects/growth & development ; }, abstract = {Lipomannan and lipoarabinomannan are integral components of the mycobacterial cell wall. Earlier studies demonstrated that synthetic arabinan and arabinomannan glycolipids acted as inhibitors of mycobacterial growth, in addition to exhibiting inhibitory activities of mycobacterial biofilm. Herein, it is demonstrated that synthetic mannan glycolipids are better inhibitors of mycobacterial growth, whereas lipoarabinomannan has a higher inhibition efficiency to biofilm. Syntheses of mannan glycolipids with a graded number of mannan moieties and an arabinomannan glycolipid are conducted by chemical methods and subsequent mycobacterial growth and biofilm inhibition studies are conducted on Mycobacterium smegmatis. Growth inhibition of (73±3) % is observed with a mannose trisaccharide containing a glycolipid, whereas this glycolipid did not promote biofilm inhibition activity better than that of arabinomannan glycolipid. The antibiotic supplementation activities of glycolipids on growth and biofilm inhibitions are evaluated. Increases in growth and biofilm inhibitions are observed if the antibiotic is supplemented with glycolipids, which leads to a significant reduction of inhibition concentrations of the antibiotic.}, } @article {pmid30950296, year = {2019}, author = {Emeri, FTAS and Rosalen, PL and Paganini, ÉR and Garcia, MAR and Nazaré, AC and Lazarini, JG and Alencar, SM and Regasini, LO and Sardi, JCO}, title = {Antimicrobial activity of nitrochalcone and pentyl caffeate against hospital pathogens results in decreased microbial adhesion and biofilm formation.}, journal = {Biofouling}, volume = {35}, number = {2}, pages = {129-142}, doi = {10.1080/08927014.2019.1574763}, pmid = {30950296}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/toxicity ; Anti-Infective Agents/*pharmacology/toxicity ; Antifungal Agents/pharmacology/toxicity ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; Caffeic Acids/*pharmacology/toxicity ; Candida albicans/drug effects ; Cell Line ; Cell Survival/drug effects ; Chalcones/*pharmacology/toxicity ; Cross Infection/prevention & control ; Humans ; Keratinocytes/cytology/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Moths/drug effects ; Staphylococcus aureus/drug effects ; }, abstract = {The present study investigated the antimicrobial, anti-adhesion and anti-biofilm activity of the modified synthetic molecules nitrochalcone (NC-E05) and pentyl caffeate (C5) against microorganisms which have a high incidence in hospital-acquired infections. The compounds were further tested for their preliminary systemic toxicity in vivo. NC-E05 and C5 showed antimicrobial activity, with minimum inhibitory concentrations (MICs) ranging between 15.62 and 31.25 μg ml[-1]. Treatment with NC-E05 and C5 at 1 × MIC and/or 10 × MIC significantly reduced mono or mixed-species biofilm formation and viability. At MIC/2, the compounds decreased microbial adhesion to HaCaT keratinocytes from 1 to 3 h (p < 0.0001). In addition, NC-E05 and C5 demonstrated low toxicity in vivo in the Galleria mellonella model at anti-biofilm concentrations. Thus, the chemical modification of these molecules proved to be effective in the proposed anti-biofilm activity, opening opportunities for the development of new antimicrobials.}, } @article {pmid30950292, year = {2019}, author = {Ikram, S and Heikal, A and Finke, S and Hofgaard, A and Rehman, Y and Sabri, AN and Økstad, OA}, title = {Bacillus cereus biofilm formation on central venous catheters of hospitalised cardiac patients.}, journal = {Biofouling}, volume = {35}, number = {2}, pages = {204-216}, doi = {10.1080/08927014.2019.1586889}, pmid = {30950292}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacillus cereus/drug effects/*isolation & purification ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections/microbiology ; Central Venous Catheters/*microbiology ; DNA, Bacterial/genetics ; Drug Resistance, Multiple, Bacterial ; Equipment Contamination ; Equipment and Supplies, Hospital ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Formation of bacterial biofilms is a risk with many in situ medical devices. Biofilm-forming Bacillus species are associated with potentially life-threatening catheter-related blood stream infections in immunocompromised patients. Here, bacteria were isolated from biofilm-like structures within the lumen of central venous catheters (CVCs) from two patients admitted to cardiac hospital wards. Isolates belonged to the Bacillus cereus group, exhibited strong biofilm formation propensity, and mapped phylogenetically close to the B. cereus emetic cluster. Together, whole genome sequencing and quantitative PCR confirmed that the isolates constituted the same strain and possessed a range of genes important for and up-regulated during biofilm formation. Antimicrobial susceptibility testing demonstrated resistance to trimethoprim-sulphamethoxazole, clindamycin, penicillin and ampicillin. Inspection of the genome revealed several chromosomal β-lactamase genes and a sulphonamide resistant variant of folP. This study clearly shows that B. cereus persisting in hospital ward environments may constitute a risk factor from repeated contamination of CVCs.}, } @article {pmid30949776, year = {2019}, author = {Chang, RYK and Das, T and Manos, J and Kutter, E and Morales, S and Chan, HK}, title = {Bacteriophage PEV20 and Ciprofloxacin Combination Treatment Enhances Removal of Pseudomonas aeruginosa Biofilm Isolated from Cystic Fibrosis and Wound Patients.}, journal = {The AAPS journal}, volume = {21}, number = {3}, pages = {49}, pmid = {30949776}, issn = {1550-7416}, support = {R33 AI121627/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/drug effects ; Biological Therapy/*methods ; Cell Line ; Ciprofloxacin/administration & dosage ; Combined Modality Therapy ; Cystic Fibrosis/microbiology/*therapy ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/microbiology/*therapy ; *Pseudomonas Phages ; Pseudomonas aeruginosa/drug effects/physiology/*virology ; Wound Infection/microbiology/*therapy ; }, abstract = {Antibiotic resistance in Pseudomonas aeruginosa biofilms necessitates the need for novel antimicrobial therapy with anti-biofilm properties. Bacteriophages (phages) are recognized as an ideal biopharmaceutical for combating antibiotic-resistant bacteria especially when used in combination with antibiotics. However, previous studies primarily focused on using phages against of P. aeruginosa biofilms of laboratory strains. In the present study, biofilms of six P. aeruginosa isolated from cystic fibrosis and wound patients, and one laboratory strain was treated singly and with combinations of anti-Pseudomonas phage PEV20 and ciprofloxacin. Of these strains, three were highly susceptible to the phage, while one was partially resistant and one was completely resistant. Combination treatment with PEV20 and ciprofloxacin enhanced biofilm eradication compared with single treatment. Phage and ciprofloxacin synergy was found to depend on phage-resistance profile of the target bacteria. Furthermore, phage and ciprofloxacin combination formulation protected the lung epithelial and fibroblast cells from P. aeruginosa and promoted cell growth. The results demonstrated that thorough screening of phage-resistance is crucial for designing phage-antibiotic formulation. The addition of highly effective phage could reduce the ciprofloxacin concentration required to combat P. aeruginosa infections associated with biofilm in cystic fibrosis and wound patients.}, } @article {pmid30949441, year = {2019}, author = {Buetti-Dinh, A and Galli, V and Bellenberg, S and Ilie, O and Herold, M and Christel, S and Boretska, M and Pivkin, IV and Wilmes, P and Sand, W and Vera, M and Dopson, M}, title = {Deep neural networks outperform human expert's capacity in characterizing bioleaching bacterial biofilm composition.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {22}, number = {}, pages = {e00321}, pmid = {30949441}, issn = {2215-017X}, abstract = {BACKGROUND: Deep neural networks have been successfully applied to diverse fields of computer vision. However, they only outperform human capacities in a few cases.

METHODS: The ability of deep neural networks versus human experts to classify microscopy images was tested on biofilm colonization patterns formed on sulfide minerals composed of up to three different bioleaching bacterial species attached to chalcopyrite sample particles.

RESULTS: A low number of microscopy images per category (<600) was sufficient for highly efficient computational analysis of the biofilm's bacterial composition. The use of deep neural networks reached an accuracy of classification of ∼90% compared to ∼50% for human experts.

CONCLUSIONS: Deep neural networks outperform human experts' capacity in characterizing bacterial biofilm composition involved in the degradation of chalcopyrite. This approach provides an alternative to standard, time-consuming biochemical methods.}, } @article {pmid30949156, year = {2019}, author = {He, X and Li, S and Yin, Y and Xu, J and Gong, W and Li, G and Qian, L and Yin, Y and He, X and Guo, T and Huang, Y and Lu, F and Cao, J}, title = {Membrane Vesicles Are the Dominant Structural Components of Ceftazidime-Induced Biofilm Formation in an Oxacillin-Sensitive MRSA.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {571}, pmid = {30949156}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has received increasing attention in recent years. However, the characteristics and relevant mechanisms of biofilm formation in oxacillin-sensitive MRSA (OS-MRSA) are poorly understood. This study was designed to characterize biofilm formation in OS-MRSA BWSA15 in response to ceftazidime (TZ) by comparing the methicillin-sensitive S. aureus (MSSA) strain BWSA23 and the oxacillin-resistant MRSA (OR-MRSA) strain BWSA11. The biofilms and biofilm-forming cells were observed by electron microscopy. Biofilms grown on microtiter plates were chemically decomposed and analyzed by Fourier transform infrared spectroscopy. The transcriptional regulation of genes associated with methicillin resistance, surface adhesion, fatty acid biosynthesis, and global regulation (sigma B) was investigated. A significant increase in biofilm formation ability (10.21-fold) and aggregation ability (2.56-fold) was observed in BWSA15 upon the treatment with TZ (16 μg/ml). The TZ-induced biofilm formation in BWSA15 was characterized by a disappearance of polysaccharide-like extracellular substances and an appearance of a large number of intercellular MVs from extracellular matrix. Few MVs were identified in the biofilms formed by BWSA11 and BWSA23. There was a significant upregulation of mecA, sigB, and fatty acid biosynthesis-associated genes and downregulation of icaA, icaD, clfA, clfB, and fnaA in BWSA15 upon the treatment with TZ. The formation of intracellular junctions of MVs in the biofilms of BWSA15 was mediated by a significant increase in the proportion of proteins as well as by an increase in the proportion of non-ionized carboxyl groups in fatty acids. This study demonstrated that beta-lactam antibiotics can induce biofilm formation in OS-MRSA, and the biofilm induction in OS-MRSA can mainly be attributed to exposed MVs with increased hydrophobicity rather than polysaccharide intercellular adhesins, cell wall-anchored surface proteins, and extracellular DNA.}, } @article {pmid30949142, year = {2019}, author = {Ashrafudoulla, M and Mizan, MFR and Park, H and Byun, KH and Lee, N and Park, SH and Ha, SD}, title = {Genetic Relationship, Virulence Factors, Drug Resistance Profile and Biofilm Formation Ability of Vibrio parahaemolyticus Isolated From Mussel.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {513}, pmid = {30949142}, issn = {1664-302X}, abstract = {The objective of this study was to investigate the virulence factors, genetic relationship, antibiotic resistance profile and the biofilm formation ability of Vibrio parahaemolyticus isolates on shrimp and mussel surfaces at 30°C. In this study, eight (n = 8) V. parahaemolyticus isolated from mussel were examined. We used the polymerase chain reaction (PCR) to examine the distribution of different genes, and Repetitive Extragenic Palindromic-PCR (REP-PCR) to compare the genetic relationship. Disk diffusion technique was used to assess antibiotic and multiple-antibiotic resistance. The biofilm formation assay, and field emission scanning electron microscopy (FE-SEM) were used to evaluate biofilm formation ability. Transmission Electron Microscope (TEM) was used to observe the morphological structure of bacterial cell. Our results indicated that the biofilm-associated genes, 16S rRNA, toxR, and tdh, were present in all the tested V. parahaemolyticus isolates (n = 8). Approximately, 62.5% (5 isolates among 8 isolates) isolates showed strong multiple-antibiotic resistance index with an average value of 0.56. All isolates (n = 8) showed strong genetic relationship and significant biofilm formation ability on shrimp and mussel surfaces. This study demonstrated that the presence of virulence factors, high multiple antibiotic resistance index (MARI) values, and effective biofilm formation ability of V. parahaemolyticus isolates could be a great threat to human health and economic values in future. It was also suggested that a high resistance rate to antibiotic could be ineffective for treating V. parahaemolyticus infections. The continuous monitoring of V. parahaemolyticus antibiotic, molecular and biofilm characteristics is needed to increase seafood safety.}, } @article {pmid30948051, year = {2019}, author = {Sedki, M and Hassan, RYA and Andreescu, S and El-Sherbiny, IM}, title = {Online-monitoring of biofilm formation using nanostructured electrode surfaces.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {100}, number = {}, pages = {178-185}, doi = {10.1016/j.msec.2019.02.112}, pmid = {30948051}, issn = {1873-0191}, mesh = {*Biofilms/growth & development ; Chitosan/chemistry ; *Electrochemical Techniques ; Electrodes ; Graphite/chemistry ; Microscopy, Electron, Scanning ; Nanostructures/*chemistry ; Pseudomonas aeruginosa/physiology ; Spectrometry, X-Ray Emission ; }, abstract = {The direct monitoring of biofilm formation enables valuable insights into the industrial processes, microbiology, and biomedical applications. Therefore, in the present study, nano-structured bioelectrochemical platforms were designed for sensing the formation of biofilm of P. aeruginosa along with monitoring its electrochemical/morphological changes under different stresses. Through the assay optimizations, the performances of different electrode modifiers such as reduced graphene oxide (rGO) nanosheets, hyperbranched chitosan nanoparticles (HBCs NPs), and rGO-HBCs nano-composite were tested to assess the influence of the electrode materials on biofilm progression. As a need for the anodic respiration, the bioelectrochemical responses of the adhered bacterial cells changed from a non-electrochemically active (planktonic state) to an electrochemically active (biofilm matrix) state. Our results demonstrated that electrode modifications with conductive nanostructured elements is highly sensitive and enable direct assay for the biofilm formation without any preachments. Consequently, the morphological changes in bacterial cell wall, upon switching from the planktonic state to the biofilm matrix were imaged using scanning electron microscopy (SEM), and the changes in cell wall chemical composition were monitored by the Energy Dispersive X-ray analysis (EDX). Thus, the designed microbial electrochemical system (MES) was successfully used to monitor changes in the biofilm matrix under different stresses through direct measurements of electron exchanges.}, } @article {pmid30947504, year = {2019}, author = {Paricio, L and Neufeld, B and Reynolds, M}, title = {Combined influence of nitric oxide and surface roughness in biofilm reduction across bacteria strains.}, journal = {Biointerphases}, volume = {14}, number = {2}, pages = {021004}, doi = {10.1116/1.5089246}, pmid = {30947504}, issn = {1559-4106}, mesh = {Anti-Bacterial Agents/*toxicity ; Biofilms/*drug effects/growth & development ; *Environmental Microbiology ; Equipment and Supplies/microbiology ; Gram-Negative Bacteria/*drug effects/growth & development ; Gram-Positive Bacteria/*drug effects/growth & development ; Microbial Viability/drug effects ; Nitric Oxide/*toxicity ; S-Nitrosoglutathione/toxicity ; *Surface Properties ; }, abstract = {Effective use of medical device implants is often hindered by infection, which may cause the device to be rejected from the body and seriously endanger health. Such infections are often a result of biofilm formation or microbial colonies collecting on a surface. Therefore, a challenge in the medical field is to mitigate the impact of biofilm formation in order to save thousands of lives and millions of healthcare dollars annually. The proposed strategy is to target the attachment phase of the biofilm lifecycle to try to prevent the formation of antimicrobial resistant biofilms. Prevention of bacterial attachment may be induced through the introduction of nitric oxide (NO), a small biological signaling molecule known for its antibacterial properties. NO may be delivered via release from a donating molecule incorporated in the polymer composing the medical device. The NO donor S-nitrosoglutathione (GSNO) was utilized in this study because it is a relatively stable small molecule that naturally exists in the body, therefore negating possible adverse reactions when it is introduced to the body. Tygon[®], a polymer commonly found in Food and Drug Administration approved medical devices such as catheters, was utilized as a platform for the inhibition of biofilms. To study the necessary amount of released NO needed to cause a reduction in attachment across varying strains, different concentrations of GSNO were applied. Two Gram-negative (Pseudomonas aeruginosa and Acinetobacter baumannii) and two Gram-positive species (Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus), all strong biofilm formers listed as urgent threats by the Center for Disease Control, illustrated different responses to NO. Gram-positive species showed a decrease in viability over 80% with an average total NO release of 2.01 ± 2.11 × 10 [-] [4 ]μmols, while Gram-negative response was less, with viability decreasing to 38% (P. aeruginosa) and 71% (A. baumannii) with 1.25 ± 1.63 × 10[-4 ]μmols NO. Further studies utilizing glutathione surface roughness controls highlight that increasing the surface roughness of the polymer platform produces no statistically significant difference in viability compared to the Tygon-only negative control in all strains except P. aeruginosa. Developing a quantitative understanding of how NO release and platform surface roughness impact biofilm attachment across Gram strains is key to reducing the incidence and impact of medical device associated infections.}, } @article {pmid30946803, year = {2019}, author = {Feng, J and Li, T and Yee, R and Yuan, Y and Bai, C and Cai, M and Shi, W and Embers, M and Brayton, C and Saeki, H and Gabrielson, K and Zhang, Y}, title = {Stationary phase persister/biofilm microcolony of Borrelia burgdorferi causes more severe disease in a mouse model of Lyme arthritis: implications for understanding persistence, Post-treatment Lyme Disease Syndrome (PTLDS), and treatment failure.}, journal = {Discovery medicine}, volume = {27}, number = {148}, pages = {125-138}, pmid = {30946803}, issn = {1944-7930}, mesh = {Animals ; Biofilms/*drug effects/growth & development ; Borrelia burgdorferi/*physiology ; Ceftriaxone/*pharmacokinetics ; Disease Models, Animal ; Female ; *Lyme Disease/drug therapy/microbiology/pathology ; Mice ; *Post-Lyme Disease Syndrome/drug therapy/microbiology/pathology ; Treatment Failure ; }, abstract = {Although most patients with Lyme disease can be cured with a 2-4 week antibiotic therapy, about 10-20% of patients continue to suffer prolonged persistent symptoms, a condition called post-treatment Lyme disease syndrome (PTLDS). The cause for PTLDS is unclear and hotly debated. Borrelia burgdorferi develops morphological variants under stress conditions but their significance is not clear. Here we isolated the biofilm-like microcolony (MC) and planktonic (spirochetal form and round body) (SP) variant forms from the stationary phase culture of B. burgdorferi and showed that the MC and SP variant forms were not only more tolerant to the current Lyme antibiotics but also caused more severe arthritis in mice than the log phase spirochete form (LOG). We propose to divide the persistent Lyme disease into two categories: (1) early development of persistent disease from inoculation with persister/biofilm at the beginning of infection introduced by tick bites, or Type I persistent disease (i.e., PTLDS); and (2) late development of persistent disease due to initial infection not being diagnosed or treated in time such that the infection develops into late persistent disease, or Type II persistent disease. Importantly, we show that the murine infection caused by LOG could be eradicated by ceftriaxone whereas the persistent infection established with MC could not be eradicated by doxycycline (Doxy), ceftriaxone (CefT), or vancomycin (Van), or Doxy+CefT or Van+CefT, but could only be eradicated by the persister drug combination daptomycin+doxycycline+ceftriaxone. We conclude that varying levels of persistence and pathologies of Borrelia infection and the corresponding different treatment responses are mostly dictated by the heterogeneous B. burgdorferi variant forms inoculated at the time of tick bites. These findings may have broad implications for understanding pathogenesis and treatment of not only persistent Lyme disease but also other persistent infections in general and call for studies to evaluate if treatment of persistent infections with persister drug combination regimens is more effective than the current mostly single-antibiotic monotherapy.}, } @article {pmid30941317, year = {2019}, author = {Zhang, B and Ku, X and Zhang, X and Zhang, Y and Chen, G and Chen, F and Zeng, W and Li, J and Zhu, L and He, Q}, title = {The AI-2/luxS Quorum Sensing System Affects the Growth Characteristics, Biofilm Formation, and Virulence of Haemophilus parasuis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {9}, number = {}, pages = {62}, pmid = {30941317}, issn = {2235-2988}, mesh = {Animal Structures/microbiology ; Animals ; Bacterial Load ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/deficiency/*metabolism ; Disease Models, Animal ; Gene Deletion ; Genetic Complementation Test ; Haemophilus Infections/microbiology/pathology ; Haemophilus parasuis/*drug effects/*growth & development/pathogenicity ; Homoserine/*analogs & derivatives/metabolism ; Lactones/*metabolism ; Lethal Dose 50 ; Mice, Inbred BALB C ; *Quorum Sensing ; Virulence ; Virulence Factors/deficiency/metabolism ; }, abstract = {Haemophilus parasuis (H. parasuis) is a kind of opportunistic pathogen of the upper respiratory tract of piglets. Under certain circumstances, virulent strains can breach the mucosal barrier and enter the bloodstream, causing severe Glässer's disease. Many virulence factors are found to be related to the pathogenicity of H. parasuis strain, but the pathogenic mechanism remains unclear. LuxS/AI-2, as a kind of very important quorum sensing system, affects the growth characteristics, biofilm formation, antibiotic production, virulence, and metabolism of different strains. In order to investigate the effect of luxS/AI-2 quorum sensing system on the virulence of H. parasuis, a deletion mutant strain (ΔluxS) and complemented strain (C-luxS) were constructed and characterized. The results showed that the luxS gene participated in regulating and controlling stress resistance, biofilm formation and virulence. Compared with wild-type strain, ΔluxS strain decreased the production of AI-2 molecules and the tolerance toward oxidative stress and heat shock, and it reduced the abilities of autoagglutination, hemagglutination, and adherence, whereas it increased the abilities to form biofilm in vitro. In vivo experiments showed that ΔluxS strain attenuated its virulence about 10-folds and significantly decreased its tissue burden of bacteria in mice, compared with the wild-type strain. Taken together, the luxS/AI-2 quorum sensing system in H. parasuis not only plays an important role in growth and biofilm formation, but also affects the pathogenicity of H. parasuis.}, } @article {pmid30941169, year = {2019}, author = {Shridhar, S and Dhanashree, B}, title = {Antibiotic Susceptibility Pattern and Biofilm Formation in Clinical Isolates of Enterococcus spp.}, journal = {Interdisciplinary perspectives on infectious diseases}, volume = {2019}, number = {}, pages = {7854968}, pmid = {30941169}, issn = {1687-708X}, abstract = {Enterococcus is a commensal in the intestine and is now emerging as a drug-resistant pathogen. It produces different virulence factors. Enterococcus surface protein (esp) is a virulence factor that helps in the adhesion, but its role in biofilm formation is still contradictory. Moreover, in many bacterial species, strong biofilm producer exhibits multidrug resistance. Hence, this study is done to know the antimicrobial susceptibility pattern of Enterococcus spp. and to correlate the drug resistance with biofilm production and esp gene. Enterococcal isolates were collected from various clinical specimens. Antibiotic susceptibility testing was done by disc diffusion, and biofilm production was performed by microtiter plate method. PCR was performed for detection of esp gene. Two E. faecium strains resistant to vancomycin and high-level aminoglycoside (HLAR) were non-biofilm-producers and did not harbor esp gene. However, other biofilm-producing E. faecium harbored esp gene, and this association was found to be statistically significant (p=0.024). It was observed that there was no significant association between biofilm formation and presence of esp gene in E. faecalis. Moreover, a significant correlation was not found between drug resistance and biofilm production in both Enterococcus species. Thus, biofilm formation is not always associated with the presence or absence of esp gene and or drug resistance in Enterococcus spp.}, } @article {pmid30941112, year = {2019}, author = {Sobisch, LY and Rogowski, KM and Fuchs, J and Schmieder, W and Vaishampayan, A and Oles, P and Novikova, N and Grohmann, E}, title = {Biofilm Forming Antibiotic Resistant Gram-Positive Pathogens Isolated From Surfaces on the International Space Station.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {543}, pmid = {30941112}, issn = {1664-302X}, abstract = {The International Space Station (ISS) is a closed habitat in a uniquely extreme and hostile environment. Due to these special conditions, the human microflora can undergo unusual changes and may represent health risks for the crew. To address this problem, we investigated the antimicrobial activity of AGXX®, a novel surface coating consisting of micro-galvanic elements of silver and ruthenium along with examining the activity of a conventional silver coating. The antimicrobial materials were exposed on the ISS for 6, 12, and 19 months each at a place frequently visited by the crew. Bacteria that survived on the antimicrobial coatings [AGXX® and silver (Ag)] or the uncoated stainless steel carrier (V2A, control material) were recovered, phylogenetically affiliated and characterized in terms of antibiotic resistance (phenotype and genotype), plasmid content, biofilm formation capacity and antibiotic resistance transferability. On all three materials, surviving bacteria were dominated by Gram-positive bacteria and among those by Staphylococcus, Bacillus and Enterococcus spp. The novel antimicrobial surface coating proved to be highly effective. The conventional Ag coating showed only little antimicrobial activity. Microbial diversity increased with increasing exposure time on all three materials. The number of recovered bacteria decreased significantly from V2A to V2A-Ag to AGXX®. After 6 months exposure on the ISS no bacteria were recovered from AGXX®, after 12 months nine and after 19 months three isolates were obtained. Most Gram-positive pathogenic isolates were multidrug resistant (resistant to more than three antibiotics). Sulfamethoxazole, erythromycin and ampicillin resistance were most prevalent. An Enterococcus faecalis strain recovered from V2A steel after 12 months exposure exhibited the highest number of resistances (n = 9). The most prevalent resistance genes were ermC (erythromycin resistance) and tetK (tetracycline resistance). Average transfer frequency of erythromycin, tetracycline and gentamicin resistance from selected ISS isolates was 10[-5] transconjugants/recipient. Most importantly, no serious human pathogens such as methicillin resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococci (VRE) were found on any surface. Thus, the infection risk for the crew is low, especially when antimicrobial surfaces such as AGXX® are applied to surfaces prone to microbial contamination.}, } @article {pmid30940828, year = {2019}, author = {Ghosh, R and Barman, S and Mandal, NC}, title = {Phosphate deficiency induced biofilm formation of Burkholderia on insoluble phosphate granules plays a pivotal role for maximum release of soluble phosphate.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {5477}, pmid = {30940828}, issn = {2045-2322}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Burkholderia/*growth & development/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Gene Expression Regulation, Bacterial ; Microscopy, Atomic Force ; Phosphates/*deficiency ; Quorum Sensing ; Sequence Analysis, DNA ; }, abstract = {Involvement of biofilm formation process during phosphate (P) solubilization by rhizobacterial strains is not clearly understood. Scanning electron microscopic observations revealed prominent biofilm development on tricalcium phosphate as well as on four different rock phosphate granules by two P solubilizing rhizobacteria viz. Burkholderia tropica P4 and B. unamae P9. Variation in the biofilm developments were also observed depending on the total P content of insoluble P used. Biofilm quantification suggested a strong correlation between the amounts of available P and degrees of biofilm formation. Lower concentrations of soluble P directed both the organisms towards compact biofilm development with maximum substratum coverage. Variation in the production of extracellular polymeric substances (EPS) in the similar pattern also suggested its close relationship with biofilm formation by the isolates. Presence of BraI/R quorum sensing (QS) system in both the organisms were detected by PCR amplification and sequencing of two QS associated genes viz. braR and rsaL, which are probably responsible for biofilm formation during P solubilization process. Overall observations help to hypothesize for the first time that, biofilm on insoluble P granules creates a close environment for better functioning of organic acids secreted by Burkholderia strains for maximum P solubilization during P deficient conditions.}, } @article {pmid30940709, year = {2019}, author = {Beebout, CJ and Eberly, AR and Werby, SH and Reasoner, SA and Brannon, JR and De, S and Fitzgerald, MJ and Huggins, MM and Clayton, DB and Cegelski, L and Hadjifrangiskou, M}, title = {Respiratory Heterogeneity Shapes Biofilm Formation and Host Colonization in Uropathogenic Escherichia coli.}, journal = {mBio}, volume = {10}, number = {2}, pages = {}, pmid = {30940709}, issn = {2150-7511}, support = {K08 DK106472/DK/NIDDK NIH HHS/United States ; T32 GM007347/GM/NIGMS NIH HHS/United States ; }, mesh = {Aerobiosis ; Anaerobiosis ; Biofilms/*growth & development ; *Biological Variation, Population ; *Genetic Heterogeneity ; Oxidation-Reduction ; Oxidoreductases/genetics/*metabolism ; Oxygen/*metabolism ; Uropathogenic Escherichia coli/*physiology ; }, abstract = {Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization to the biofilm community such that biofilm residents can benefit from the production of common goods while being protected from exogenous insults. Spatial organization is driven by the presence of chemical gradients, such as oxygen. Here we show that two quinol oxidases found in Escherichia coli and other bacteria organize along the biofilm oxygen gradient and that this spatially coordinated expression controls architectural integrity. Cytochrome bd, a high-affinity quinol oxidase required for aerobic respiration under hypoxic conditions, is the most abundantly expressed respiratory complex in the biofilm community. Depletion of the cytochrome bd-expressing subpopulation compromises biofilm complexity by reducing the abundance of secreted extracellular matrix as well as increasing cellular sensitivity to exogenous stresses. Interrogation of the distribution of quinol oxidases in the planktonic state revealed that ∼15% of the population expresses cytochrome bd at atmospheric oxygen concentration, and this population dominates during acute urinary tract infection. These data point toward a bet-hedging mechanism in which heterogeneous expression of respiratory complexes ensures respiratory plasticity of E. coli across diverse host niches.IMPORTANCE Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization in the biofilm community. Here we demonstrate that oxygen gradients in uropathogenic Escherichia coli (UPEC) biofilms lead to spatially distinct expression programs for quinol oxidases-components of the terminal electron transport chain. Our studies reveal that the cytochrome bd-expressing subpopulation is critical for biofilm development and matrix production. In addition, we show that quinol oxidases are heterogeneously expressed in planktonic populations and that this respiratory heterogeneity provides a fitness advantage during infection. These studies define the contributions of quinol oxidases to biofilm physiology and suggest the presence of respiratory bet-hedging behavior in UPEC.}, } @article {pmid30939384, year = {2019}, author = {Wu, ZY and Liu, Y and Wang, SY and Peng, P and Li, XY and Xu, J and Li, WH}, title = {A novel integrated system of three-dimensional electrochemical reactors (3DERs) and three-dimensional biofilm electrode reactors (3DBERs) for coking wastewater treatment.}, journal = {Bioresource technology}, volume = {284}, number = {}, pages = {222-230}, doi = {10.1016/j.biortech.2019.03.123}, pmid = {30939384}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Coke/*analysis ; Electrochemical Techniques/instrumentation/*methods ; Electrodes ; Nitrogen/metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater/*chemistry ; }, abstract = {Treatment of coking wastewater is a great challenge due to their instinct characteristics of high concentration, complex composition and biological toxicity. In this work, a novel integrated system comprising three-dimensional electrochemical reactors (3DERs) and three-dimensional biofilm electrode reactors (3DBERs) in series is developed for coking wastewater treatment. Results indicate that 79.63% of COD as well as 76.30% of total nitrogen could be removed at the low energy consumption of 15.6 kWh/m[3]. 3DERs mainly contribute to COD and nitrogen removal through electrochemical oxidation/reduction, while 3DBERs are responsible for nitrification process by enriched functional microbes. After treating by the integrated system, only long-chain alkanes are left in the wastewater and the toxicity of effluent is significantly reduced. This integrated 3DERs-3DBERs system exhibits capability of simultaneously eliminating carbonaceous and nitrogenous contaminants in coking wastewater, and greatly saves the energy with synergy of electricity and biofilm.}, } @article {pmid30937747, year = {2020}, author = {Li, J and Zhu, W and Dong, H and Yang, Z and Zhang, P and Qiang, Z}, title = {Impact of carrier on ammonia and organics removal from zero-discharge marine recirculating aquaculture system with sequencing batch biofilm reactor (SBBR).}, journal = {Environmental science and pollution research international}, volume = {27}, number = {28}, pages = {34614-34623}, pmid = {30937747}, issn = {1614-7499}, support = {51878362//National Natural Science Foundation of China/ ; 2017M610410//China Postdoctoral Science Foundation/ ; 2018T110665//China Postdoctoral Science Foundation/ ; 18K02ESPCR//State Key Joint Laboratory of Environment Simulation and Pollution Control/ ; }, mesh = {*Ammonia ; Aquaculture ; Biofilms ; *Bioreactors ; Nitrogen ; Waste Disposal, Fluid ; }, abstract = {Marine recirculating aquaculture system (MRAS) is an effective technology that provides sustainable farming of food fish globally. However, dissolved organics material (chemical oxygen demand, COD) and especially ammonia are produced from uneaten feed and metabolic wastes of fish. To purify the MRAS water, this study adopted a sequencing biofilm batch reactor (SBBR) and comparatively investigated the performances of four different carriers on ammonia and COD removal. Results indicated that the NH4[+]-N removal rates were 0.045 ± 0.05, 0.065 ± 0.008, 0.089 ± 0.005, and 0.093 ± 0.003 kg/(m[3]·d), and the COD removal rates were 0.019 ± 0.010, 0.213 ± 0.010, 0.255 ± 0.015, and 0.322 ± 0.010 kg/(m[3]·d) in the SBBRs packed with porous plastic, bamboo ring, maifan stone, and ceramsite carriers, respectively. Among the four carriers, ceramsite exhibited the best performance for both NH4[+]-N (80%) and COD (33%) removal after the SBBR reached the steady-state operation conditions. For all carriers studied, the NH4[+]-N removal kinetics could be well simulated by the first-order model, and the NH4[+]-N and COD removal rates were logarithmically correlated with the carrier's specific surface area. Due to its high ammonia removal, stable performance and easy operation, the ceramsite-packed SBBR is feasible for MRAS water treatment.}, } @article {pmid30937696, year = {2019}, author = {Mi, L and Liu, Y and Wang, C and He, T and Gao, S and Xing, S and Huang, Y and Fan, H and Zhang, X and Yu, W and Mi, Z and Tong, Y and Bai, C and Han, F}, title = {Identification of a lytic Pseudomonas aeruginosa phage depolymerase and its anti-biofilm effect and bactericidal contribution to serum.}, journal = {Virus genes}, volume = {55}, number = {3}, pages = {394-405}, pmid = {30937696}, issn = {1572-994X}, mesh = {Biofilms/*growth & development ; Drug Resistance, Multiple/genetics ; Humans ; Pseudomonas Infections/genetics/microbiology/*virology ; Pseudomonas Phages/*genetics/pathogenicity ; Pseudomonas aeruginosa/pathogenicity/*virology ; Sewage/microbiology/virology ; }, abstract = {Pseudomonas aeruginosa (P. aeruginosa) infection has imposed a great threat to patients with cystic fibrosis. With the emergence of multidrug-resistant P. aeruginosa, developing an alternative anti-microbial strategy is indispensable and more urgent than ever. In this study, a lytic P. aeruginosa phage was isolated from the sewage of a hospital, and one protein was predicted as the depolymerase-like protein by genomic sequence analysis, it includes two catalytic regions, the Pectate lyase_3 super family and Glycosyl hydrolase_28 super family. Further analysis demonstrated that recombinant depolymerase-like protein degraded P. aeruginosa exopolysaccharide and enhanced bactericidal activity mediated by serum in vitro. Additionally, this protein disrupted host bacterial biofilms. All of these results showed that the phage-derived depolymerase-like protein has the potential to be developed into an anti-microbial agent that targets P. aeruginosa.}, } @article {pmid30936939, year = {2019}, author = {Lu, L and Hu, W and Tian, Z and Yuan, D and Yi, G and Zhou, Y and Cheng, Q and Zhu, J and Li, M}, title = {Developing natural products as potential anti-biofilm agents.}, journal = {Chinese medicine}, volume = {14}, number = {}, pages = {11}, pmid = {30936939}, issn = {1749-8546}, abstract = {Biofilm is a natural form of bacterial growth ubiquitously in environmental niches. The biofilm formation results in increased resistance to negative environmental influences including resistance to antibiotics and antimicrobial agents. Quorum sensing (QS) is cell-to-cell communication mechanism, which plays an important role in biofilm development and balances the environment when the bacteria density becomes high. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. Accumulated evidences demonstrated that natural products from plants had antimicrobial and chemo-preventive properties in modulation of biofilm formation in the last two decades. This review will summarize recent studies on the discovery of natural anti-biofilm agents from plants with clear-cut mechanisms or identified molecular addresses, as well as some herbs with unknown mechanisms or unidentified bioactive ingredients. We also focus on the progression of techniques on the extraction and identification of natural anti-biofilm substances. Besides, anti-biofilm therapeutics undergoing clinical trials are discussed. These newly discovered natural anti-biofilm agents are promising candidates which could provide novel strategies for biofilm-associated infections.}, } @article {pmid30936487, year = {2019}, author = {He, L and Le, KY and Khan, BA and Nguyen, TH and Hunt, RL and Bae, JS and Kabat, J and Zheng, Y and Cheung, GYC and Li, M and Otto, M}, title = {Resistance to leukocytes ties benefits of quorum sensing dysfunctionality to biofilm infection.}, journal = {Nature microbiology}, volume = {4}, number = {7}, pages = {1114-1119}, pmid = {30936487}, issn = {2058-5276}, support = {Z01 AI001080-01//Intramural NIH HHS/United States ; ZIA AI000904//Intramural NIH HHS/United States ; ZIA AI000904-17//Intramural NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Catheter-Related Infections/immunology/*microbiology ; Cells, Cultured ; Disease Models, Animal ; Female ; Humans ; *Immune Evasion ; Leukocytes/*immunology ; Mice, Inbred C57BL ; Microbial Viability ; Mutation ; Quorum Sensing/genetics/*physiology ; Staphylococcal Infections/immunology/*microbiology ; Staphylococcal Skin Infections/immunology/microbiology ; Staphylococcus aureus/genetics/growth & development/*immunology/physiology ; Trans-Activators/genetics ; }, abstract = {Social interactions play an increasingly recognized key role in bacterial physiology[1]. One of the best studied is quorum sensing (QS), a mechanism by which bacteria sense and respond to the status of cell density[2]. While QS is generally deemed crucial for bacterial survival, QS-dysfunctional mutants frequently arise in in vitro culture. This has been explained by the fitness cost an individual mutant, a 'quorum cheater', saves at the expense of the community[3]. QS mutants are also often isolated from biofilm-associated infections, including cystic fibrosis lung infection[4], as well as medical device infection and associated bacteraemia[5-7]. However, despite the frequently proposed use of QS blockers to control virulence[8], the mechanisms underlying QS dysfunctionality during infection have remained poorly understood. Here, we show that in the major human pathogen Staphylococcus aureus, quorum cheaters arise exclusively in biofilm infection, while in non-biofilm-associated infection there is a high selective pressure to maintain QS control. We demonstrate that this infection-type dependence is due to QS-dysfunctional bacteria having a significant survival advantage in biofilm infection because they form dense and enlarged biofilms that provide resistance to phagocyte attacks. Our results link the benefit of QS-dysfunctional mutants in vivo to biofilm-mediated immune evasion, thus to mechanisms that are specific to the in vivo setting. Our findings explain why QS mutants are frequently isolated from biofilm-associated infections and provide guidance for the therapeutic application of QS blockers.}, } @article {pmid30936159, year = {2019}, author = {Fahmi, T and Faozia, S and Port, GC and Cho, KH}, title = {The Second Messenger c-di-AMP Regulates Diverse Cellular Pathways Involved in Stress Response, Biofilm Formation, Cell Wall Homeostasis, SpeB Expression, and Virulence in Streptococcus pyogenes.}, journal = {Infection and immunity}, volume = {87}, number = {6}, pages = {}, pmid = {30936159}, issn = {1098-5522}, support = {U01 AI025903/AI/NIAID NIH HHS/United States ; P30 CA091842/CA/NCI NIH HHS/United States ; UL1 TR000448/TR/NCATS NIH HHS/United States ; UL1 TR002345/TR/NCATS NIH HHS/United States ; R15 GM101603/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Cell Wall/genetics/*metabolism ; Cyclic AMP/*metabolism ; Exotoxins/*genetics/metabolism ; Female ; Gene Expression Regulation, Bacterial ; Homeostasis ; Humans ; Male ; Mice ; Mice, Hairless ; Second Messenger Systems ; Streptococcal Infections/*microbiology ; Streptococcus pyogenes/genetics/*pathogenicity/*physiology ; Virulence ; }, abstract = {Cyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. The cellular level of c-di-AMP in Streptococcus pyogenes is predicted to be controlled by the synthase DacA and two putative phosphodiesterases, GdpP and Pde2. To investigate the role of c-di-AMP in S. pyogenes, we generated null mutants in each of these proteins by gene deletion. Unlike those in other Gram-positive pathogens such as Staphylococcus aureus and Listeria monocytogenes, DacA in S. pyogenes was not essential for growth in rich media. The DacA null mutant presented a growth defect that manifested through an increased lag time, produced no detectable biofilm, and displayed increased susceptibility toward environmental stressors such as high salt, low pH, reactive oxygen radicals, and cell wall-targeting antibiotics, suggesting that c-di-AMP plays significant roles in crucial cellular processes involved in stress management. The Pde2 null mutant exhibited a lower growth rate and increased biofilm formation, and interestingly, these phenotypes were distinct from those of the null mutant of GdpP, suggesting that Pde2 and GdpP play distinctive roles in c-di-AMP signaling. DacA and Pde2 were critical to the production of the virulence factor SpeB and to the overall virulence of S. pyogenes, as both DacA and Pde2 null mutants were highly attenuated in a mouse model of subcutaneous infection. Collectively, these results show that c-di-AMP is an important global regulator and is required for a proper response to stress and for virulence in S. pyogenes, suggesting that its signaling pathway could be an attractive antivirulence drug target against S. pyogenes infections.}, } @article {pmid30936108, year = {2019}, author = {Usui, M and Yokoo, H and Tamura, Y and Nakajima, C and Suzuki, Y and Ghigo, JM and Beloin, C}, title = {Zinc Acetate Potentiates the Action of Tosufloxacin against Escherichia coli Biofilm Persisters.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {6}, pages = {}, pmid = {30936108}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Synergism ; Escherichia coli/*drug effects/growth & development ; Escherichia coli Infections/*drug therapy/microbiology ; Fluoroquinolones/*pharmacology ; Humans ; Naphthyridines/pharmacology ; Zinc Acetate/*pharmacology ; }, abstract = {Formation of bacterial biofilms is a major health threat due to their high levels of tolerance to multiple antibiotics and the presence of persisters responsible for infection relapses. We previously showed that a combination of starvation and induction of SOS response in biofilm led to increased levels of persisters and biofilm tolerance to fluoroquinolones. In this study, we hypothesized that inhibition of the SOS response may be an effective strategy to target biofilms and fluoroquinolone persister cells. We tested the survival of Escherichia coli biofilms to different classes of antibiotics in starved and nonstarved conditions and in the presence of zinc acetate, a SOS response inhibitor. We showed that zinc acetate potentiates, albeit moderately, the activity of fluoroquinolones against E. coli persisters in starved biofilms. The efficacy of zinc acetate to increase fluoroquinolone activity, particularly that of tosufloxacin, suggests that such a combination may be a potential strategy for treating biofilm-related bacterial infections.}, } @article {pmid30935149, year = {2019}, author = {Ma, Z and Bumunang, EW and Stanford, K and Bie, X and Niu, YD and McAllister, TA}, title = {Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel Coupons as Affected by Temperature and Incubation Time.}, journal = {Microorganisms}, volume = {7}, number = {4}, pages = {}, pmid = {30935149}, issn = {2076-2607}, support = {FOS.07.17//Beef Cattle Research Council To Agriculture and Agri-Food Canada and Alberta Agriculture and Forestry/ ; 0001//Chinese Ministry of Education/ ; }, abstract = {Forming biofilm is a strategy utilized by Shiga toxin-producing Escherichia coli (STEC) to survive and persist in food processing environments. We investigated the biofilm-forming potential of STEC strains from 10 clinically important serogroups on stainless steel at 22 °C or 13 °C after 24, 48, and 72 h of incubation. Results from crystal violet staining, plate counts, and scanning electron microscopy (SEM) identified a single isolate from each of the O113, O145, O91, O157, and O121 serogroups that was capable of forming strong or moderate biofilms on stainless steel at 22 °C. However, the biofilm-forming strength of these five strains was reduced when incubation time progressed. Moreover, we found that these strains formed a dense pellicle at the air-liquid interface on stainless steel, which suggests that oxygen was conducive to biofilm formation. At 13 °C, biofilm formation by these strains decreased (P < 0.05), but gradually increased over time. Overall, STEC biofilm formation was most prominent at 22 °C up to 24 h. The findings in this study identify the environmental conditions that may promote STEC biofilm formation in food processing facilities and suggest that the ability of specific strains to form biofilms contributes to their persistence within these environments.}, } @article {pmid30934181, year = {2019}, author = {Jirawatnotai, S and Mahachitsattaya, B}, title = {Analysis of subclinical infections and biofilm formation in cases of capsular contracture after silicone augmentation rhinoplasty: Prevalence and microbiological study.}, journal = {Archives of plastic surgery}, volume = {46}, number = {2}, pages = {160-166}, pmid = {30934181}, issn = {2234-6163}, abstract = {BACKGROUND: Implant-related deformities in aesthetic rhinoplasty are a major problem for rhinoplasty surgeons. Capsular contracture is believed to be the pathological cause of delayed contour deformities, comparable to breast implant-related contracture. This study investigated the prevalence of bacterial biofilms and other epidemiological factors related to capsular contracture in cases of silicone augmentation rhinoplasty.

METHODS: Thirty-three patients who underwent corrective rhinoplasty due to a delayed contour deformity or aesthetic revision after implant rhinoplasty were studied from December 2014 to December 2016. All recruited patients received surgical correction by the authors. The patients were categorized by clinical severity into four grades. Demographic data and related confounding factors were recorded. Samples of capsular tissue and silicone removed from each patient were analyzed for the presence of a biofilm by ultrasonication with bacterial culture and scanning electron microscopy.

RESULTS: Thirty-three paired samples of capsular tissue and silicone implants from the study group were analyzed. Biofilms were detected in one of 10 subjects (10%) with grade 1 contracture, two of four (50%) with grade 2 contracture, 10 of 14 (71.40%) with grade 3 contracture, and four of five (80%) with grade 4 contracture (P<0.05). The organisms found were Staphylococcus epidermidis (47.10%), coagulase-negative staphylococci (35.30%), and Staphylococcus aureus (17.60%).

CONCLUSIONS: As with breast implant-related capsular contracture, silicone nasal augmentation deformities likely result from bacterial biofilms. We demonstrated the prevalence of biofilms in patients with various degrees of contracture. Implant type and operative technique seemed to have only vague correlations with biofilm presence.}, } @article {pmid30933902, year = {2019}, author = {Dige, I and Nyvad, B}, title = {Candida species in intact in vivo biofilm from carious lesions.}, journal = {Archives of oral biology}, volume = {101}, number = {}, pages = {142-146}, doi = {10.1016/j.archoralbio.2019.03.017}, pmid = {30933902}, issn = {1879-1506}, mesh = {*Biofilms ; Candida/*isolation & purification ; Dental Caries/*microbiology ; Dental Plaque/*microbiology ; Humans ; In Situ Hybridization, Fluorescence ; }, abstract = {OBJECTIVES: The aim of this study was to investigate the occurrence and spatial localization of Candida species in intact in vivo biofilm from caries lesions in root and occlusal surfaces.

MATERIALS AND METHODS: Biofilm from 7 teeth with root caries and 9 teeth with occlusal caries were analyzed. The teeth were fixed, embedded, sectioned and decalcified before fluorescence in situ hybridization using oligonucleotide probes against all bacteria (EUB338), all yeast (PF2), streptococci (STR405, MUT590) and C. albicans (Du.al 1249). Sections were analyzed using fluorescence microscopy.

RESULTS: Yeasts, most of which were C. albicans or C. dubliniensis, colonized occlusal and root surface sites and exhibited both yeast and hyphal forms. Two characteristic colonization patterns were apparent: In one pattern, the biofilm presented defined areas comprising Candida hyphal networks mixed with filamentous, rod-like and coccoid bacteria, often extending through the entire biofilm thickness. In the other pattern, Candida formed corncob configurations with non-mutans streptococci in the biofilm surface layer. Mutans streptococci formed isolated colonies and did not typically appear in close proximity with Candida.

CONCLUSION: For the first time, we showed that C. albicans and C. dubliniensis are integrated components of caries biofilm architecture. Co-localization of Candida and non-mutans streptococci indicates a beneficial interaction between these organisms. Diverse metabolic properties of Candida spp. suggest that these organisms may influence the ecology of cross-kingdom microbial communities in caries.}, } @article {pmid30929087, year = {2019}, author = {Zhang, LY and Fang, ZH and Li, QL and Cao, CY}, title = {A tooth-binding antimicrobial peptide to prevent the formation of dental biofilm.}, journal = {Journal of materials science. Materials in medicine}, volume = {30}, number = {4}, pages = {45}, pmid = {30929087}, issn = {1573-4838}, mesh = {Animals ; Anti-Bacterial Agents/metabolism/pharmacology ; Anti-Infective Agents/*metabolism/pharmacokinetics ; Biofilms/*drug effects ; Cattle ; Dental Caries/microbiology/prevention & control ; Dental Plaque/microbiology/*prevention & control ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Peptide Fragments/*metabolism/pharmacokinetics ; Protein Binding ; Streptococcus mutans/drug effects ; Surface Properties ; Tooth/*metabolism ; }, abstract = {Dental caries is primarily caused by pathogenic bacteria infection, and Streptococcus mutans is considered a major cariogenic pathogen. Moreover, antimicrobial peptides have been considered an alternative to traditional antibiotics in treating caries. This study aimed to design a tooth-binding antimicrobial peptide and evaluate its antimicrobial efficacy against S. mutans. An antimicrobial peptide of polyphemusin I (PI) was modified by grafting a tooth-binding domain of diphosphoserine (Ser(p)-Ser(p)-) to create the peptide of Ser(p)-Ser(p)-polyphemusin I (DPS-PI). PI and DPS-PI were synthesized by Fmoc solid-phase peptide synthesis. The minimum inhibitory concentration of PI and DPS-PI against S. mutans were tested. Scanning electron microscopy (SEM) were used to observe the growth of S. mutans on PI and DPS-PI treated enamel surfaces. The growth of S. mutans was evaluated by optical density (OD) at 590 nm. Inhibition of dental plaque biofilm development in vivo were investigated. The cytocompatibility to bone mesenchymal stem cells (BMSCs) was tested. The MIC of PI and DPS-PI were 40 and 80 μg/ml, respectively. SEM images showed that S. mutans were sparsely distributed on the DPS-PI treated enamel surface. OD findings indicated that DPS-PI maintained its inhibition effect on S. mutans growth after 24 h. The incisor surfaces of rabbits treated with DPS-PI developed significantly less dental plaque biofilm than that on PI treated surfaces. The DPS-PI had good biocompatibility with the cells. We successfully constructed a novel tooth-binding antimicrobial peptide against S. mutans in vitro and inhibited dental plaque biofilm development in vivo. DPS-PI may provide a feasible alternative to conventional antibiotics for the prevention and treatment of dental caries. Dental caries is primarily caused by pathogenic bacteria infection, and Streptococcus mutans is considered a major cariogenic pathogen. A tooth-binding antimicrobial peptide was designed by grafted diphosphoserine (-Ser(p)-Ser(p)-) to the structure of polyphemusin I. This novel tooth-binding antimicrobial peptide can inhibit dental plaque biofilm development and thus provide a feasible alternative to conventional antibiotics for the prevention and treatment of dental caries.}, } @article {pmid30928423, year = {2019}, author = {Lin, MF and Lin, YY and Lan, CY}, title = {A method to assess influence of different medical tubing on biofilm formation by Acinetobacter baumannii.}, journal = {Journal of microbiological methods}, volume = {160}, number = {}, pages = {84-86}, doi = {10.1016/j.mimet.2019.03.023}, pmid = {30928423}, issn = {1872-8359}, mesh = {Acinetobacter baumannii/*physiology ; *Biofilms ; Catheter-Related Infections/*microbiology ; Humans ; Latex/chemistry ; Polyvinyl Chloride/chemistry ; Silicones/chemistry ; }, abstract = {In this study, we developed a method to assess influence of different medical tubing on biofilm formation by A. baumannii. The results of biofilm quantification and scanning electron microscopy showed that the biofilm formation susceptibility of different tubing materials was rubber latex > polyvinyl chloride > silicone.}, } @article {pmid30927751, year = {2019}, author = {Roila, R and Ranucci, D and Valiani, A and Galarini, R and Servili, M and Branciari, R}, title = {Antimicrobial and anti-biofilm activity of olive oil by-products against Campylobacter spp. isolated from chicken meat.}, journal = {Acta scientiarum polonorum. Technologia alimentaria}, volume = {18}, number = {1}, pages = {43-52}, doi = {10.17306/J.AFS.0629}, pmid = {30927751}, issn = {1898-9594}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Campylobacter/*drug effects ; Chickens ; Food Industry ; *Food Microbiology ; Industrial Waste/analysis ; Meat/*microbiology ; Olive Oil/*chemistry ; Wastewater/chemistry ; }, abstract = {BACKGROUND: Worldwide, poultry is considered the main source of food-related human campylobacteriosis, which is generally associated with the consumption of raw or undercooked chicken meat. Furthermore, Cam- pylobacter develops biofilms that are resistant to environmental stress, antibiotics, and disinfectants and are becoming a major issue for the food industry, especially the poultry industry. This study investigated the antimicrobial and anti-biofilm properties of polyphenols found in spray-dried olive mill wastewater (OMWW--SD) against Campylobacter strains isolated from chicken meat.

METHODS: OMWW-SD was produced by dehydration of olive mill wastewater polyphenolic extract. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for OMWW-SD were determined by microdilution method whereas the inhibitory effect of the OMWW-SD on biofilm formation and biofilm disaggregation was tested through crystal violet assay on polystyrene plates.

RESULTS: The phenolic profile of OMWW-SD mainly consisted of secoiridoid and hydroxycinnamic acid derivatives. Oleuropein-aglycone di-aldehyde (a secoiridoid derivative) was the major constituent, representing 72.5% of the total identified phenolic compounds. OMWW-SD showed a MIC ranging from 0.15 mg/mL to 0.3 mg/mL and a MBC of 0.3 mg/mL for all Campylobacter strains tested. The olive by-product extract tested was able, in vitro, to inhibit biofilm formation and to promote biofilm dispersion even at sub-MIC concentra- tions, with values ranging from 6% to 92% and from 4% to 83% at varying extract dilutions, respectively.

CONCLUSIONS: OMWW-SD could be developed as a new anti-biofilm agent with potential to control Campylo- bacter in the food chain, especially in the poultry industry, thereby enhancing food safety.}, } @article {pmid30927638, year = {2019}, author = {Wei, Z and Yu, S and Huang, Z and Xiao, X and Tang, M and Li, B and Zhang, X}, title = {Simultaneous removal of elemental mercury and NO by mercury induced thermophilic community in membrane biofilm reactor.}, journal = {Ecotoxicology and environmental safety}, volume = {176}, number = {}, pages = {170-177}, doi = {10.1016/j.ecoenv.2019.03.082}, pmid = {30927638}, issn = {1090-2414}, mesh = {Biofilms/*growth & development ; Bioreactors/*microbiology ; Denitrification ; Mercury/*analysis ; Metagenomics ; Microbiota/drug effects/genetics ; Nitric Oxide/*analysis ; Nitrification ; Oxidation-Reduction ; }, abstract = {Thermophilic membrane biofilm reactor (TMBR) for elemental mercury (Hg[0]) and NO removal in simulated flue gas was investigated at oxygen content of 6% and 60 °C. The performance, the microbial community structures, gene function and the mechanism for Hg[0] and NO removal in the TMBR were evaluated. TMBR achieved effective simultaneous Hg[0] and NO removal in 210 days of operation, Hg[0] and NO removal efficiency were up to 88.9% and 85.3%, respectively. Mercury induced thermophilic community had been formed significantly. Comamonas, Pseudomonas, Desulfomicrobium, Burkholderia and Halomonas were thermophilic mercury resistant bacteria. Brucella, Paracoccus, Tepidiphilus, Proteobacteria, Pseudomonas and Symbiobacterium were nitrifying/denitrifying genera, and had functional genes of mercury and nitrogen metabolism, as shown by16S rDNA and metagenomic sequencing. The biofilm in TMBR was characterized by XPS, HPLC. XPS and HPLC spectra indicate the formation of a mercuric species (Hg[2+]) from mercury oxidation. TMBR used oxygen as electron acceptor, NO and Hg[0] as electron donor in nitrification; O2, NO and NO3[-] could be used as electron acceptor and Hg[0] as electron donor in denitrification.}, } @article {pmid30927492, year = {2019}, author = {Patel, A and Carlson, RP and Henson, MA}, title = {In Silico Metabolic Design of Two-Strain Biofilm Systems Predicts Enhanced Biomass Production and Biochemical Synthesis.}, journal = {Biotechnology journal}, volume = {14}, number = {7}, pages = {e1800511}, doi = {10.1002/biot.201800511}, pmid = {30927492}, issn = {1860-7314}, support = {W911NF-16-1-0463//Army Research Office/ ; }, mesh = {Biofilms/*growth & development ; *Biomass ; Coculture Techniques ; *Computer Simulation ; Escherichia coli/metabolism ; Geobacter/metabolism ; *Metabolic Engineering ; *Models, Biological ; }, abstract = {Engineered biofilm consortia have the potential to solve important biotechnological problems that have proved difficult for monoculture biofilms and planktonic consortia, such as conversion of lignocellulosic material to useful biochemicals. While considerable experimental progress has been reported for engineering and characterizing biofilm consortia, the field still lacks in silico tools for simulation, design, and optimization of stable, robust, and productive designed consortia. We developed biofilm consortia metabolic models for two coculture systems centered around the ecological design motif of a primary cell type that utilizes a supplied electron donor and secretes acetate as a byproduct and a secondary cell type that consumes the acetate, relieving byproduct inhibition on the primary cell type and enhancing overall system biomass. The models presented in this paper predict that distinct metabolic niches for the two cell types could be established by supplying electron donors and acceptors at opposite ends of the biofilm and that acetate consumption by the secondary cell type could increase total biomass accumulation and the synthesis of valuable biochemicals, such as isobutanol, by the primary cell type. System tunability is enhanced when each cell type is supplied with a unique terminal electron acceptor at opposite ends of the biofilm rather than competing for a common electron acceptor. Our model provides good qualitative agreement with data for a synthetic Escherichia coli coculture system, suggesting that the proposed design rules may have wide applicability to engineered biofilm consortia.}, } @article {pmid30927413, year = {2019}, author = {Aziz, K and Tariq, M and Zaidi, A}, title = {Biofilm development in L. fermentum under shear flow & sequential GIT digestion.}, journal = {FEMS microbiology letters}, volume = {366}, number = {6}, pages = {}, doi = {10.1093/femsle/fnz064}, pmid = {30927413}, issn = {1574-6968}, mesh = {Bacterial Adhesion ; *Biofilms ; Caco-2 Cells ; Gastrointestinal Tract/*microbiology ; Humans ; Limosilactobacillus fermentum/*physiology ; Models, Biological ; }, abstract = {The objective of this study was to investigate biofilm formation by Lactobacillus fermentum under physiologically relevant shear conditions both in the presence and absence of a food matrix and under simulated conditions of digestion. This was done using batch and flow biofilms of L. fermentum strains under conditions simulating digestion in the human gastrointestinal tract and shear flow using a high throughput platform BioFlux 1000Z system. The putative probiotic strain, PL29, was found to be capable of adhesion and biofilm formation in mucin-coated microfluidic channels under liquid flow conditions mimicking those of the GIT. Based on these in vitro measurements, we conclude that L. fermentum strain PL29 could be an effective probiotic for human consumption.}, } @article {pmid30926870, year = {2019}, author = {Olwal, CO and Ang'ienda, PO and Ochiel, DO}, title = {Alternative sigma factor B (σ[B]) and catalase enzyme contribute to Staphylococcus epidermidis biofilm's tolerance against physico-chemical disinfection.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {5355}, pmid = {30926870}, issn = {2045-2322}, mesh = {*Biofilms/drug effects ; Catalase/*genetics/metabolism ; Disinfectants/pharmacology ; *Disinfection/methods ; *Drug Tolerance ; Humans ; Hydrogen Peroxide/pharmacology ; Sigma Factor/*genetics/metabolism ; Sodium Hypochlorite/pharmacology ; Staphylococcus epidermidis/*drug effects/*physiology ; }, abstract = {Staphylococcus epidermidis is the predominant cause of recalcitrant biofilm-associated infections, which are often highly resistant to antibiotics. Thus, the use of physico-chemical agents for disinfection offers a more effective approach to the control of S. epidermidis biofilm infections. However, the underlying tolerance mechanisms employed by S. epidermidis biofilm against these physico-chemical disinfectants remain largely unknown. The expression of a σ[B]-dependent gene, alkaline shock protein 23 (asp23) and catalase activity by S. epidermidis biofilm and planktonic cells exposed to heat (50 °C), 0.8 M sodium chloride (NaCl), 5 mM sodium hypochlorite (NaOCl) or 50 μM hydrogen peroxide (H2O2) for 60 minutes were compared. Significantly higher asp23 expression levels were observed in biofilms exposed to 50 °C, 5 mM NaOCl or 50 μM H2O2 compared to the corresponding planktonic cells (p < 0.05). Conversely, asp23 expression levels in biofilm and planktonic cells exposed to 0.8 M NaCl were not significantly different (p > 0.05). Further, biofilms exposed to 50 °C, 0.8 M NaCl, 5 mM NaOCl or 50 μM H2O2 exhibited significantly higher catalase activity than the planktonic cells (p < 0.05). These results suggest that activities of σ[B] and catalase may be involved in the tolerance of S. epidermidis biofilm against physico-chemical disinfection.}, } @article {pmid30926526, year = {2019}, author = {Patel, KK and Tripathi, M and Pandey, N and Agrawal, AK and Gade, S and Anjum, MM and Tilak, R and Singh, S}, title = {Alginate lyase immobilized chitosan nanoparticles of ciprofloxacin for the improved antimicrobial activity against the biofilm associated mucoid P. aeruginosa infection in cystic fibrosis.}, journal = {International journal of pharmaceutics}, volume = {563}, number = {}, pages = {30-42}, doi = {10.1016/j.ijpharm.2019.03.051}, pmid = {30926526}, issn = {1873-3476}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/drug effects ; Chitosan/*administration & dosage/chemistry ; Ciprofloxacin/*administration & dosage/chemistry ; Cystic Fibrosis/drug therapy ; Drug Liberation ; Enzymes, Immobilized/*administration & dosage/chemistry ; Erythrocytes/drug effects ; Hemolysis/drug effects ; Humans ; Lung/drug effects ; Male ; Nanoparticles/*administration & dosage/chemistry ; Platelet Aggregation/drug effects ; Polysaccharide-Lyases/*administration & dosage/chemistry ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects/physiology ; Rats, Wistar ; }, abstract = {Dense colonization of mucoid Pseudomonas aeruginosa within the self-secreted extracellular matrix (mainly alginate), called biofilm, is a principal reason for the failure of antimicrobial therapy in cystic fibrotic patients. Alginate is a key component in the biofilm of mucoid P. aeruginosa and responsible for surface adhesion and stabilization of biofilm. To overcome this problem, alginate lyase functionalized chitosan nanoparticles of ciprofloxacin were developed for the effective treatment of P. aeruginosa infection in cystic fibrosis patients. The developed nanoparticles were found to have desired quality attributes and demonstrated sustained release following the Higuchi release kinetics. Drug compatibility with the chitosan was confirmed by FTIR while powder X-ray diffraction analysis confirmed the entrapment of drug within the nanoparticle matrix. Lactose adsorbed NPs showed promising aerodynamic property. Nanoparticles showed prolonged MIC and significant reduction in biofilm aggregation and formation in planktonic bacterial suspension. Nanoparticles exhibited significantly higher inhibitory effect against biofilm of P. aeruginosa and reduced the biomass, thickness and density confirmed by confocal microscopy. Furthermore, developed nanoparticles were haemocompatible and did not exhibit any toxicity in vitro MTT assay and in vivo on lungs male Wistar rats. The data in hand collectively suggest the proposed strategy a better alternative for the effective treatment of cystic fibrosis infections.}, } @article {pmid30924805, year = {2019}, author = {Sandip, M and Kalyanraman, V}, title = {Enhanced simultaneous nitri-denitrification in aerobic moving bed biofilm reactor containing polyurethane foam-based carrier media.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {79}, number = {3}, pages = {510-517}, doi = {10.2166/wst.2019.077}, pmid = {30924805}, issn = {0273-1223}, mesh = {Biofilms ; *Bioreactors ; *Denitrification ; Nitrogen ; Polyurethanes/*chemistry ; Waste Disposal, Fluid/*methods ; }, abstract = {Fluidization of carrier media for biofilm support and growth defines the moving bed biofilm reactor (MBBR) process. Major MBBR facilities apply virgin polyethylene (PE)-based circular plastic carrier media. Various carriers were studied to replace these conventional carriers, but polyurethane (PU) foam-based carrier media has not been much explored. This study evaluates the potential of PU foam carrier media in aerobic MBBR process for simultaneous nitri-denitrification (SND). Two parallel reactors loaded with conventional PE plastic (circular) and PU foam (cubical) carriers compared for their removal efficiencies of chemical oxygen demand (COD) and nitrogen contaminants from wastewater. Results indicate that average COD removal in MBBR containing PE plastic carrier media was 81%, compared to 83% in MBBR containing PU foam. Average ammonical and total nitrogen reduction was 71% and 59% for PU foam-based MBBR, compared to 60% and 42% for PE plastic-based MBBR. SND-based nitrogen removal capacity was doubled in aerobic MBBR filled with PU foam carrier media (27%), than MBBR containing PE plastic carrier media (13%). Cost economics also governs the commercial advantage for the application of PU foam-based carrier media in the MBBR process.}, } @article {pmid30924795, year = {2019}, author = {Metcalf, D and Bowler, PG}, title = {Perceptions of Wound Biofilm by Wound Care Clinicians.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {31}, number = {3}, pages = {E14-E17}, pmid = {30924795}, issn = {1943-2704}, mesh = {Anti-Infective Agents/therapeutic use ; Attitude of Health Personnel ; *Biofilms/drug effects ; Europe ; Health Knowledge, Attitudes, Practice ; Health Services Research ; Humans ; *Marketing ; Perception ; *Physicians ; United States ; Wound Healing/*physiology ; Wound Infection/diagnosis/*microbiology ; }, abstract = {OBJECTIVE: The aim of this study was to gain a greater understanding of the perceptions of wound biofilm held by wound care clinicians.

METHODS: Independent market research was conducted in the United States and Europe via an online questionnaire to understand the knowledge levels of wound biofilm among clinicians.

RESULTS: Clinicians from the United States appeared most knowledgeable on the subject of wound biofilm, though there was a wider consensus that biofilm contributes to delayed wound healing. A number of visual and indirect clinical signs for the presence of wound biofilm were commonly listed by all clinicians. In this study, and others, widespread calls for further education on wound biofilm, in addition to anti-biofilm and diagnostic technologies, were made.

CONCLUSIONS: This study has contributed to the global call to focus on tackling biofilm for the benefit of wound care patients, caregivers, and health care systems.}, } @article {pmid30924535, year = {2019}, author = {Silva, AF and Dos Santos, AR and Trevisan, DAC and Bonin, E and Freitas, CF and Batista, AFP and Hioka, N and Simões, M and Graton Mikcha, JM}, title = {Xanthene Dyes and Green LED for the Inactivation of Foodborne Pathogens in Planktonic and Biofilm States.}, journal = {Photochemistry and photobiology}, volume = {95}, number = {5}, pages = {1230-1238}, doi = {10.1111/php.13104}, pmid = {30924535}, issn = {1751-1097}, mesh = {*Biofilms ; Coloring Agents/*chemistry/pharmacology ; *Food Microbiology ; Microscopy, Electron, Scanning ; Salmonella typhimurium/*drug effects ; Staphylococcus aureus/*drug effects ; Xanthenes/*chemistry/pharmacology ; }, abstract = {This study evaluated the rose bengal- and erythrosine-mediated photoinactivation against Salmonella Typhimurium and Staphylococcus aureus planktonic and sessile cells using green LED as a light source. The free-living or 2-day-old biofilm cells were treated with different concentrations of the photosensitizing agents and subjected to irradiation. Only 5 min photosensitization with rose bengal at 25 nmol L[-1] and 75 μmol L[-1] completely eliminated S. aureus and S. Typhimurium planktonic cells, respectively. Erythrosine at 500 nmol L[-1] and 5 min of light exposure also reduced S. aureus planktonic cells to undetectable levels. Eradication of S. aureus biofilms was achieved when 500 μmol L[-1] of erythrosine or 250 μmol L[-1] of rose bengal was combined with 30 min of irradiation. Scanning electron microscopy allowed the observation of morphological changes in planktonic cells and disruption of the biofilm architecture after photodynamic treatment. The overall data demonstrate that rose bengal and erythrosine activated by green LED may be a targeted strategy for controlling foodborne pathogens in both planktonic and sessile states.}, } @article {pmid30917333, year = {2019}, author = {Mardanpour, MM and Saadatmand, M and Yaghmaei, S}, title = {Interpretation of the electrochemical response of a multi-population biofilm in a microfluidic microbial fuel cell using a comprehensive model.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {128}, number = {}, pages = {39-48}, doi = {10.1016/j.bioelechem.2019.03.003}, pmid = {30917333}, issn = {1878-562X}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Chemotaxis ; Electrochemical Techniques/*methods ; *Microfluidics ; *Models, Biological ; }, abstract = {The present study investigates the diversification and dynamic behavior of a multi-population microfluidic microbial fuel cell (MFC) as a biosensor. The cost effective microfluidic MFC coupled to a comprehensive model, presents a novel platform for monitoring chemical and biological phenomena. The importance of competition among different microbial groups, hierarchical biochemical processes, bacterial chemotaxis and different mechanisms of electron transfer were significant considerations in the present model. The validation of the model using experimental data from a microfluidic MFC shows an appropriate match with the hierarchal biodegradation processes of a complex substrate as well as development of bacterial chemotaxis during multi-population biofilm formation under real conditions. Microfluidic MFC performance, including temporal and spatial distribution of different microbial group concentrations in the biofilm and anolyte bulk, the competitive behavior of different species, bacterial transport parameters and bioelectrochemical characteristics are also assessed.}, } @article {pmid30917172, year = {2019}, author = {Chatterjee, S and Biswas, N and Datta, A and Maiti, PK}, title = {Periodicities in the roughness and biofilm growth on glass substrate with etching time: Hydrofluoric acid etchant.}, journal = {PloS one}, volume = {14}, number = {3}, pages = {e0214192}, pmid = {30917172}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Glass/*chemistry ; Hydrofluoric Acid/*chemistry ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; Surface Properties ; }, abstract = {Adherence of the microorganism to submerged solid surfaces leads to biofilm formation. Biofilm formation modifies the surfaces in favor of bacteria facilitating the survival of the bacteria under different stressed conditions. On the other hand, the formation of biofilm has a direct adverse economic impact in various industries and more importantly in medical practices. This adherence is the reason for the failure of many indwelling medical devices. Surface biofilm adhesion is the key to biofilm growth and stability. Hence this adhesion needs to be substantially lowered to inhibit biofilm stability. Both chemical and physical properties of the surface influence biofilm formation and modulating these properties can control this formation. In this study, we have investigated the effect of Hydrofluoric acid (HF), at a specific concentration as an etchant, on the surface morphology of substrates and the growth of biofilms of Pseudomonas aeruginosa. and Staphylococcus aureus. We find that the bacterial counts on the etched surfaces undergo a periodic increase and decrease. This, on one hand, shows the close correlation between the biofilm growth and the particular roughness scale, and on the other hand, explains the existing contradictory results regarding the effects of etching on substrate roughness and biofilm growth. We propose a simple model of a sequence of hole formation, hole expansion and etching away of the hole walls to form a new, comparatively smooth surface, coupled with the preferential accumulation of bacteria at the hole edges, to explain these periodicities.}, } @article {pmid30915345, year = {2019}, author = {Zannier, F and Portero, LR and Ordoñez, OF and Martinez, LJ and Farías, ME and Albarracin, VH}, title = {Polyextremophilic Bacteria from High Altitude Andean Lakes: Arsenic Resistance Profiles and Biofilm Production.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {1231975}, pmid = {30915345}, issn = {2314-6141}, mesh = {Acinetobacter/drug effects/genetics/*growth & development ; Adaptation, Physiological/*genetics ; Altitude ; Arsenic/toxicity ; Biodegradation, Environmental ; Biofilms/drug effects/growth & development ; *Ecosystem ; Lakes/microbiology ; *Phylogeny ; Ultraviolet Rays ; }, abstract = {High levels of arsenic present in the High Altitude Andean Lakes (HAALs) ecosystems selected arsenic-resistant microbial communities which are of novel interest to study adaptations mechanisms potentially useful in bioremediation processes. We herein performed a detailed characterization of the arsenic tolerance profiles and the biofilm production of two HAAL polyextremophiles, Acinetobacter sp. Ver3 (Ver3) and Exiguobacterium sp. S17 (S17). Cellular adherence over glass and polypropylene surfaces were evaluated together with the effect of increasing doses and oxidative states of arsenic over the quality and quantity of their biofilm production. The arsenic tolerance outcomes showed that HAAL strains could tolerate higher arsenic concentrations than phylogenetic related strains belonging to the German collection of microorganisms and cell cultures (Deutsche Sammlung von Mikroorganismen und Zellkulturen, DSMZ), which suggest adaptations of HAAL strains to their original environment. On the other hand, the crystal violet method (CV) and SEM analysis showed that Ver3 and S17 were able to attach to solid surfaces and to form the biofilm. The quantification of biofilms production in 48 hours' cultures through CV shows that Ver3 yielded higher production in the treatment without arsenic cultured on a glass support, while S17 yield higher biofilm production under intermediate arsenic concentration on glass supports. Polypropylene supports had negative effects on the biofilm production of Ver3 and S17. SEM analysis shows that the highest biofilm yields could be associated with a larger number of attached cells as well as the development of more complex 3D multicellular structures.}, } @article {pmid30914689, year = {2019}, author = {Naranjo, E and Merfa, MV and Ferreira, V and Jain, M and Davis, MJ and Bahar, O and Gabriel, DW and De La Fuente, L}, title = {Liberibacter crescens biofilm formation in vitro: establishment of a model system for pathogenic 'Candidatus Liberibacter spp.'.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {5150}, pmid = {30914689}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; *Lab-On-A-Chip Devices ; Liberibacter ; *Microfluidic Analytical Techniques ; *Models, Biological ; *Rhizobiaceae/pathogenicity/physiology ; Serum Albumin, Bovine/chemistry ; }, abstract = {The Liberibacter genus comprises insect endosymbiont bacterial species that cause destructive plant diseases, including Huanglongbing in citrus and zebra chip in potato. To date, pathogenic 'Candidatus Liberibacter spp.' (CLs) remain uncultured, therefore the plant-associated Liberibacter crescens (Lcr), only cultured species of the genus, has been used as a biological model for in vitro studies. Biofilm formation by CLs has been observed on the outer midgut surface of insect vectors, but not in planta. However, the role of biofilm formation in the life cycle of these pathogens remains unclear. Here, a model system for studying CLs biofilms was developed using Lcr. By culture media modifications, bovine serum albumin (BSA) was identified as blocking initial cell-surface adhesion. Removal of BSA allowed for the first time observation of Lcr biofilms. After media optimization for biofilm formation, we demonstrated that Lcr attaches to surfaces, and form cell aggregates embedded in a polysaccharide matrix both in batch cultures and under flow conditions in microfluidic chambers. Biofilm structures may represent excellent adaptive advantages for CLs during insect vector colonization helping with host retention, immune system evasion, and transmission. Future studies using the Lcr model established here will help in the understanding of the biology of CLs.}, } @article {pmid30913464, year = {2019}, author = {Abinaya, M and Gayathri, M}, title = {Inhibition of biofilm formation, quorum sensing activity and molecular docking study of isolated 3, 5, 7-Trihydroxyflavone from Alstonia scholaris leaf against P.aeruginosa.}, journal = {Bioorganic chemistry}, volume = {87}, number = {}, pages = {291-301}, doi = {10.1016/j.bioorg.2019.03.050}, pmid = {30913464}, issn = {1090-2120}, mesh = {Alstonia/*chemistry ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Flavonoids/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Molecular Structure ; Plant Leaves/*chemistry ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Structure-Activity Relationship ; }, abstract = {The current study is to evaluate the inhibition of biofilm formation and quorum sensing activity of isolated 3, 5, 7-Trihydroxyflavone (TF) from A.scholaris leaf extract against Pseudomonas aeruginosa. The effects of isolated TF on quorum sensing-regulated virulence factors production such as swimming motility, pyocyanin production, proteolytic, EPS, metabolic assay and inhibition of biofilm formation against P.aeruginosa was evaluated by standard protocols. In addition, the interaction between the isolated TF and active sites of QS- gene (LasI/rhlI, LasR/rhlR, and AHLase) in P.aeruginosa was evaluated by molecular docking studies using AutoDock Tools version 1.5.6. Based on the structural elucidation of the isolated compound was identified as 3, 5, 7-Trihydroxyflavone. Consequently, the isolated TF shows a significant reduction of biofilm formation through the inhibition of QS-dependent phenotypes such as pyocyanin production, proteolytic, swimming motility, EPS activities against P.aeruginosa in a dose-dependent manner. Molecular docking analysis of isolated TF can interfere the signaling [N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL)] molecules in P.aeruginosa by QS genes (LasI, LasR, rhlI, and AHLase) regulation. The isolated TF compound from A.scholaris reveals a greater potential to inhibit biofilm and QS dependent virulence factor production in P.aeruginosa. Docking interaction studies of TF-LasR complex express higher binding affinity than the other QS gene in P.aeruginosa.}, } @article {pmid30913433, year = {2019}, author = {Montoya-Rosales, JJ and Olmos-Hernández, DK and Palomo-Briones, R and Montiel-Corona, V and Mari, AG and Razo-Flores, E}, title = {Improvement of continuous hydrogen production using individual and binary enzymatic hydrolysates of agave bagasse in suspended-culture and biofilm reactors.}, journal = {Bioresource technology}, volume = {283}, number = {}, pages = {251-260}, doi = {10.1016/j.biortech.2019.03.072}, pmid = {30913433}, issn = {1873-2976}, mesh = {Agave/*metabolism ; *Biofilms ; Biofuels ; Cellulose/*metabolism ; Fermentation ; Hydrogen/*metabolism ; Hydrolysis ; }, abstract = {Continuous hydrogen (H2) production from individual (Stonezyme, IH) and binary (Celluclast-Viscozyme, BH) enzymatic hydrolysates of agave bagasse was evaluated in continuous stirred-tank reactors (CSTR) and trickling bed reactors (TBR). The volumetric H2 production rates (VHPR) in CSTR were 13 and 2.25 L H2/L-d with BH and IH, respectively. Meanwhile, VHPR of 5.76 and 2.0 L H2/L-d were obtained in the TBR configuration using BH and IH, respectively. Differences on VHPR between reactors could be explained by substrate availability, which is intrinsic to the growth mode of each reactor configuration; while differences of VHPR between hydrolysates were possibly related to the composition of enzymatic hydrolysates. Furthermore, homoacetogenesis was strongly influenced by H2 and substrate transfer conditions. Considering VHPR, H2 yields, and costs of hydrolysis, hydrogen production from binary hydrolysates of agave bagasse was identified as the most promising alternative evaluated with scale-up potential for the production of energy biofuels.}, } @article {pmid30912922, year = {2019}, author = {Wang, Y and Kadiyala, U and Qu, Z and Elvati, P and Altheim, C and Kotov, NA and Violi, A and VanEpps, JS}, title = {Anti-Biofilm Activity of Graphene Quantum Dots via Self-Assembly with Bacterial Amyloid Proteins.}, journal = {ACS nano}, volume = {13}, number = {4}, pages = {4278-4289}, pmid = {30912922}, issn = {1936-086X}, support = {K08 AI128006/AI/NIAID NIH HHS/United States ; }, mesh = {Amyloidogenic Proteins/*metabolism ; Anti-Bacterial Agents/metabolism/*pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects ; Graphite/metabolism/*pharmacology ; Humans ; Models, Molecular ; Quantum Dots/metabolism ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Bacterial biofilms represent an essential part of Earth's ecosystem that can cause multiple ecological, technological, and health problems. The environmental resilience and sophisticated organization of biofilms are enabled by the extracellular matrix that creates a protective network of biomolecules around the bacterial community. Current anti-biofilm agents can interfere with extracellular matrix production but, being based on small molecules, are degraded by bacteria and rapidly diffuse away from biofilms. Both factors severely reduce their efficacy, while their toxicity to higher organisms creates additional barriers to their practicality. In this paper, we report on the ability of graphene quantum dots to effectively disperse mature amyloid-rich Staphylococcus aureus biofilms, interfering with the self-assembly of amyloid fibers, a key structural component of the extracellular matrix. Mimicking peptide-binding biomolecules, graphene quantum dots form supramolecular complexes with phenol-soluble modulins, the peptide monomers of amyloid fibers. Experimental and computational results show that graphene quantum dots efficiently dock near the N-terminus of the peptide and change the secondary structure of phenol-soluble modulins, which disrupts their fibrillation and represents a strategy for mitigation of bacterial communities.}, } @article {pmid30911404, year = {2019}, author = {Greener, J}, title = {On the nature of "skeletal" biofilm patterns, "hidden" heterogeneity and the role of bubbles to reveal them.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {12}, pmid = {30911404}, issn = {2055-5008}, mesh = {*Biofilms ; }, abstract = {A short communication on the recent paper by Jang et al. discusses the role of "mushroom" structures and effects of nearly static bubbles on nascent biofilms.}, } @article {pmid30910809, year = {2019}, author = {Korir, ML and Dale, JL and Dunny, GM}, title = {Role of epaQ, a Previously Uncharacterized Enterococcus faecalis Gene, in Biofilm Development and Antimicrobial Resistance.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {30910809}, issn = {1098-5530}, support = {R01 AI122742/AI/NIAID NIH HHS/United States ; R35 GM118079/GM/NIGMS NIH HHS/United States ; TL1 TR002493/TR/NCATS NIH HHS/United States ; UL1 TR002494/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cell Membrane/genetics ; Drug Resistance, Bacterial/*genetics ; Enterococcus faecalis/drug effects/*genetics/*physiology ; Humans ; Operon/genetics ; }, abstract = {Enterococcus faecalis is a commensal of the human gastrointestinal tract; it is also an opportunistic pathogen and one of the leading causes of hospital-acquired infections. E. faecalis produces biofilms that are highly resistant to antibiotics, and it has been previously reported that certain genes of the epa operon contribute to biofilm-associated antibiotic resistance. Despite several studies examining the epa operon, many gene products of this operon remain annotated as hypothetical proteins. Here, we further explore the epa operon; we identified epaQ, currently annotated as encoding a hypothetical membrane protein, as being important for biofilm formation in the presence of the antibiotic daptomycin. Mutants with disruptions of epaQ were more susceptible to daptomycin relative to the wild type, suggesting its importance in biofilm-associated antibiotic resistance. Furthermore, the ΔepaQ mutant exhibited an altered biofilm architectural arrangement and formed small aggregates in liquid cultures. Our cumulative data show that epa mutations result in altered polysaccharide content, increased cell surface hydrophobicity, and decreased membrane potential. Surprisingly, several epa mutations significantly increased resistance to the antibiotic ceftriaxone, indicating that the way in which the epa operon impacts antibiotic resistance is antibiotic dependent. These results further define the key role of epa in antibiotic resistance in biofilms and in biofilm architecture.IMPORTANCEE. faecalis is a common cause of nosocomial infection, has a high level of antibiotic resistance, and forms robust biofilms. Biofilm formation is associated with increased antibiotic resistance. Therefore, a thorough understanding of biofilm-associated antibiotic resistance is important for combating resistance. Several genes from the epa operon have previously been implicated in biofilm-associated antibiotic resistance, pathogenesis, and competitive fitness in the GI tract, but most genes in this locus remain uncharacterized. Here, we examine epaQ, which has not been characterized functionally. We show that the ΔepaQ mutant exhibits reduced biofilm formation in the presence of daptomycin, altered biofilm architecture, and increased resistance to ceftriaxone, further expanding our understanding of the contribution of this operon to intrinsic enterococcal antibiotic resistance and biofilm growth.}, } @article {pmid30909644, year = {2019}, author = {Wijesundara, NM and Rupasinghe, HPV}, title = {Bactericidal and Anti-Biofilm Activity of Ethanol Extracts Derived from Selected Medicinal Plants against Streptococcus pyogenes.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {6}, pages = {}, pmid = {30909644}, issn = {1420-3049}, support = {CRDPJ 448052//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; *Biofilms ; Chromatography, High Pressure Liquid/methods ; Ethanol/chemistry ; Flowers/chemistry ; Microbial Sensitivity Tests ; Phytochemicals/*pharmacology ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Plant Roots/chemistry ; Plant Stems/chemistry ; Plants, Medicinal/*chemistry ; Streptococcus pyogenes/*drug effects ; Tandem Mass Spectrometry/methods ; }, abstract = {Background: There is a growing interest in medicinal plants which have been traditionally used for the treatment of human infections. This study assessed 14 ethanol extracts (EEs) on bacterial growth and biofilm formation of Streptococcus pyogenes. Methods: Constituent major phytochemicals in the extracts were identified using ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Micro-broth dilution and time-kill assays were used to determine antibacterial activities. Anti-biofilm activities were studied using MTT assay, and morphology of biofilms was observed by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was employed to visualize the ultra-cross section structure of bacteria treated with efficacious extracts. Results: Licorice root, purple coneflower flower, purple coneflower stem, sage leaves and slippery elm inner bark EEs were the most effective, with minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of 62.5 μg/mL and 125 μg/mL, respectively. The minimum biofilm inhibitory concentration (MBIC) of extracts ranged from 31.5[-]250 μg/mL. Morphological changes were observed in treated biofilms compared to the untreated. The four most effective extracts exhibited the ability to induce degradation of bacterial cell wall and disintegration of the plasma membrane. Conclusion: We suggest that EEs of sage leaf and purple coneflower flower are promising candidates to be further investigated for developing alternative natural therapies for the management of streptococcal pharyngitis.}, } @article {pmid30909573, year = {2019}, author = {Lagha, R and Ben Abdallah, F and Al-Sarhan, BO and Al-Sodany, Y}, title = {Antibacterial and Biofilm Inhibitory Activity of Medicinal Plant Essential Oils Against Escherichia coli Isolated from UTI Patients.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {6}, pages = {}, pmid = {30909573}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/drug effects ; Escherichia coli/drug effects/pathogenicity ; Escherichia coli Infections/*drug therapy/microbiology ; Gas Chromatography-Mass Spectrometry ; Humans ; Microbial Sensitivity Tests ; Oils, Volatile/chemistry/*pharmacology ; Origanum/chemistry ; Plant Extracts/chemistry/pharmacology ; Plants, Medicinal/chemistry ; Rosmarinus/*chemistry ; Thymus Plant/*chemistry ; Urinary Tract Infections/*drug therapy/microbiology ; }, abstract = {Urinary tract infections (UTIs), caused by Escherichia coli 80% to 85% of the time, are one of the most important causes of morbidity and health care spending affecting persons of all ages. These infections lead to many difficult problems, especially increasing resistance to antibiotic drugs. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. In this study, we have investigated the antibacterial activity of five medicinal plant essential oils against UTIs caused by E. coli using disc diffusion and minimal inhibition concentration (MIC) methods. In addition, biofilm inhibitory action of oils was realized by crystal violet. Gas chromatography[-]mass spectrometry (GC[-]MS) analysis showed a variability between oils in terms of compound numbers as well as their percentages. Antibacterial activity was observed only in cases of Origanum majorana, Thymus zygis and Rosmarinus officinalis, while Juniperus communis and Zingiber officinale did not showed any effect towards E. coli isolates. T. zygis essential oil demonstrated the highest antibacterial activity against E. coli isolates, followed by O. majorana and R. officinalis. Further, oils showed high biofilm inhibitory action with a percentage of inhibition that ranged from 14.94% to 94.75%. R. officinalis oil had the highest antibiofilm activity followed by T. zygis and O. majorana. Accordingly, tested oils showed very effective antibacterial and antibiofilm activities against E. coli UTIs and can be considered as good alternative for antibiotics substitution.}, } @article {pmid30909069, year = {2019}, author = {Méndez-Tovar, M and García-Meza, JV and González, I}, title = {Electrochemical monitoring of Acidithiobacillus thiooxidans biofilm formation on graphite surface with elemental sulfur.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {128}, number = {}, pages = {30-38}, doi = {10.1016/j.bioelechem.2019.03.004}, pmid = {30909069}, issn = {1878-562X}, mesh = {Acidithiobacillus thiooxidans/growth & development/*metabolism ; Biofilms/*growth & development ; Electrochemical Techniques/*methods ; Graphite/*chemistry ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Electron, Scanning ; Spectrum Analysis, Raman/methods ; Sulfur/*chemistry ; Surface Properties ; }, abstract = {Inorganic wastewaters and sediments from the mining industry and mineral bioleaching processes have not been fully explored in bioelectrochemical systems (BES). Knowledge of interfacial changes due to biofilm evolution under acidic conditions may improve applications in electrochemical processes, specifically those related to sulfur compounds. Biofilm evolution of Acidithiobacillus thiooxidans on a graphite plate was monitored by electrochemical techniques, using the graphite plate as biofilm support and elemental sulfur as the only energy source. Even though the elemental sulfur was in suspension, S[0] particles adhered to the graphite surface favoring biofilm development. The biofilms grown at different incubation times (without electric perturbation) were characterized in a classical three electrode electrochemical cell (sulfur and bacteria free culture medium) by non-invasive electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The biofilm structure was confirmed by Environmental Scanning Electrode Microscopy, while the relative fractions of exopolysaccharides and extracellular hydrophobic compounds at different incubation times were evaluated by Confocal Laser Scanning Microscopy. The experimental conditions chosen in this work allowed the EIS monitoring of the biofilm growth as well as the modification of Extracellular Polymeric Substances (EPS) composition (hydrophobic/ exopolysaccharides EPS ratio). This strategy could be useful to control biofilms for BES operation under acidic conditions.}, } @article {pmid30908986, year = {2019}, author = {Zheng, Z and Huang, S and Bian, W and Liang, D and Wang, X and Zhang, K and Ma, X and Li, J}, title = {Enhanced nitrogen removal of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm reactor for treating mainstream wastewater under low dissolved oxygen (DO) concentration.}, journal = {Bioresource technology}, volume = {283}, number = {}, pages = {213-220}, doi = {10.1016/j.biortech.2019.01.148}, pmid = {30908986}, issn = {1873-2976}, mesh = {*Biofilms ; Denitrification ; Nitrification ; Nitrogen/*metabolism ; Nitrosomonas/metabolism ; Oxidation-Reduction ; Oxygen/*metabolism ; Wastewater/*chemistry ; }, abstract = {The simultaneous partial nitrification, anammox and denitrification (SNAD) process for treating mainstream wastewater was investigated under different intermittent aeration modes. By controlling the aeration time of 20, 60 and 180 min during the intermittent modes, the oxygen concentration remained 3.50, 1.45 and 0.70 mg·L[-1]. Correspondingly, the reactor achieved the nitrogen removal rate of 0.17, 0.29 and 0.30 kg N·m[-3]·d[-1]. Meanwhile, the average total inorganic nitrogen (TIN) removal efficiency reached 93.4%, 87.5% and 92.7%. The effluent NO3[-]-N concentration was very low. High-throughput sequencing analysis indicated that the proportion of nitrite oxidization bacteria (NOB), anammox bacteria and denitrification bacteria was 0.15%, 0.33% and 8.78%. Candidatus Anammoxoglobus was the abundant anammox bacteria genus. Further study on the unclassified sequences revealed the possibility of the high relative abundance of Nitrosomonas-related genus and Candidatus Kuenenia-related genus on the SNAD biofilm.}, } @article {pmid30908836, year = {2019}, author = {Alrabiah, M and Alshagroud, RS and Alsahhaf, A and Almojaly, SA and Abduljabbar, T and Javed, F}, title = {Presence of Candida species in the subgingival oral biofilm of patients with peri-implantitis.}, journal = {Clinical implant dentistry and related research}, volume = {21}, number = {4}, pages = {781-785}, doi = {10.1111/cid.12760}, pmid = {30908836}, issn = {1708-8208}, support = {RG-1438-075//College of Dentistry, King Saud University/ ; }, mesh = {*Alveolar Bone Loss ; Biofilms ; Candida ; *Dental Implants ; Humans ; Male ; Middle Aged ; *Peri-Implantitis ; Periodontal Index ; }, abstract = {BACKGROUND: There are no studies that have investigated the presence of Candida species in the subgingival oral biofilm (OB) of patients with peri-implantitis.

PURPOSE: The aim was to assess the presence of Candida species in the subgingival OB of patients with peri-implantitis.

MATERIALS AND METHODS: Individuals with (group A) and without (group B) peri-implantitis were included. Life style related and demographic data were collected using a questionnaire. In both groups, peri-implant plaque-index (PI), bleeding-on-probing (BOP), and probing-depth (PD) were evaluated and crestal bone loss (CBL) were measured on digital bitewing radiographs. In both groups, subgingival OB samples were collected using sterile paper points. Identification of Candida species was performed using ChromAgar medium and colony forming units per milliliter (CFU/mL) were determined. Statistical analysis was performed, and level of significance was set at P < 0.05.

RESULTS: The mean age of individuals in groups A (n = 43) and B (n = 41) were 52.2 ± 4.4 and 55.1 ± 2.3 years, respectively. All participants were male. In groups A and B, implants were in function for 7.4 ± 1.3 and 6.8 ± 0.6 years, respectively. Scores of peri-implant PI (P < 0.001), BOP (P < 0.001), PD (P < 0.001), and CBL (P < 0.001) were significantly higher in group A than group B. Subgingival Candida was isolated from the OB of 33 (76.7%) patients in group A and 5 (12.2%) individuals in group B. The most common yeast species was Candida albicans, which was isolated from 67.4% to 60% individuals in groups A and B, respectively. The number of subgingival oral yeasts CFU/mL were significantly higher in group A (3147.54 ± 1052.6 CFU/mL) compared with group B (496.68 ± 100.2 CFU/mL; P < 0.01).

CONCLUSION: Candida species (predominantly C. albicans) are present in the subgingival OB of patients with peri-implantitis. Community-based efforts toward routine oral hygiene maintenance are needed to improve oral health and minimize the risks of peri-implant diseases in populations.}, } @article {pmid30905995, year = {2019}, author = {Malhotra, R and Dhawan, B and Garg, B and Shankar, V and Nag, TC}, title = {A Comparison of Bacterial Adhesion and Biofilm Formation on Commonly Used Orthopaedic Metal Implant Materials: An In vitro Study.}, journal = {Indian journal of orthopaedics}, volume = {53}, number = {1}, pages = {148-153}, pmid = {30905995}, issn = {0019-5413}, abstract = {BACKGROUND: Bacterial adherence and biofilm formation on the surface of biomaterials can often lead to implant-related infections, which may vary depending on the species of microorganisms, type of biomaterial used, and physical characteristics of implant surfaces. However, there are limited studies specifically comparing biofilm formation between commonly used metallic orthopaedic implant materials and different bacterial strains. This in vitro study is to evaluate the ability of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa to adhere to and to form biofilms on the surface of five orthopaedic biomaterials, viz., cobalt and chromium, highly cross-linked polyethylene, stainless steel, trabecular metal, and titanium alloy.

MATERIALS AND METHODS: Bacterial adherence and bacterial biofilm-formation assays were performed by culturing S. aureus ATCC 29213, S. epidermidis ATCC 35984, E. coli ATCC 35218, K. pneumoniae ATCC 700603, and P. aeruginosa ATCC 27853 for 48 h on five different biomaterials. Quantitative bacterial adherence and biofilm formation were analyzed with a scanning electron microscope.

RESULTS: The highest level of adherence was observed on highly cross-linked polyethylene, followed by titanium, stainless steel, and trabecular metal, with the lowest occurring on the cobalt-chromium alloy. Among the bacterial strains tested, the ability for high adherence was observed with S. epidermidis and K. pneumoniae followed by P. aeruginosa and E. coli, whereas S. aureus showed the least adherence.

CONCLUSION: Cobalt-chromium was observed to have the lowest proclivity towards bacterial adherence compared to the other biomaterials tested. However, bacterial adhesion occurred with all the materials. Hence, it is necessary to further evaluate newer biomaterials that are resistant to bacterial adherence.}, } @article {pmid30903821, year = {2019}, author = {Hossain, MI and Cheng, L and Cord-Ruwisch, R}, title = {Energy efficient COD and N-removal from high-strength wastewater by a passively aerated GAO dominated biofilm.}, journal = {Bioresource technology}, volume = {283}, number = {}, pages = {148-158}, doi = {10.1016/j.biortech.2019.03.056}, pmid = {30903821}, issn = {1873-2976}, mesh = {Bacteria ; *Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/microbiology ; Denitrification ; Nitrification ; Nitrogen/*metabolism ; Nitrosomonas/physiology ; Oxygen/*metabolism ; Sewage/microbiology ; Waste Disposal, Fluid/instrumentation/methods ; Wastewater/*chemistry ; }, abstract = {Conventional aerobic treatment of high-strength wastewater is not economical due to excessively high energy requirement for compressed air supply. The use of passive aeration avoids the use of compressed air and enables energy efficient oxygen supply directly from the air. This study evaluates a passively aerated simultaneous nitrification and denitrification performing biofilm to treat concentrated wastewater. The biofilm reactor was operated > 5-months under alternating anaerobic/aerobic conditions. For 4-times concentrated wastewater, > 80% COD (2307 mg L[-1] h[-1]) and > 60% N (60 mg L[-1] h[-1]) was removed at a hydraulic retention time (HRT) of 7 h. A double application in the same reactor enabled > 95% COD and 85% N-removal, at an overall HRT of 14 h which is substantially shorter than what traditional activated sludge-based systems would require for the treatment of such concentrated feeds. Microbial community analysis showed Candidatus competibacter (27%) and nitrifying bacteria (Nitrosomonas, and Nitrospira) as key microbes involved in COD and N-removal, respectively.}, } @article {pmid30902863, year = {2019}, author = {Rondeau, M and Esmaeel, Q and Crouzet, J and Blin, P and Gosselin, I and Sarazin, C and Pernes, M and Beaugrand, J and Wisniewski-Dyé, F and Vial, L and Faure, D and Clément, C and Ait Barka, E and Jacquard, C and Sanchez, L}, title = {Biofilm-Constructing Variants of Paraburkholderia phytofirmans PsJN Outcompete the Wild-Type Form in Free-Living and Static Conditions but Not In Planta.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {11}, pages = {}, pmid = {30902863}, issn = {1098-5336}, mesh = {Arabidopsis/microbiology ; Arabidopsis Proteins/metabolism ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Burkholderiaceae/cytology/genetics/growth & development/*metabolism ; Carbon-Sulfur Lyases ; Defensins/metabolism ; HSP70 Heat-Shock Proteins/genetics ; Mutation ; Plant Immunity ; Plant Roots/microbiology ; Quorum Sensing/genetics ; Stress, Physiological ; Whole Genome Sequencing ; }, abstract = {Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In a spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several microbe-associated molecular patterns (MAMPs), including exopolysaccharides (EPS), flagellin, and GroEL. Interestingly, the variants induce low PR1 and PDF1.2 expression compared to that of the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an iron-sulfur cluster: hscA (encoding a cochaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in a heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and coexpress a variant that outcompete the wild-type form in free-living and static conditions but not in plantaIMPORTANCEParaburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta, and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in a heterogeneous environment.}, } @article {pmid30901676, year = {2019}, author = {Jovanovic, M and Radivojevic, J and O'Connor, K and Blagojevic, S and Begovic, B and Lukic, V and Nikodinovic-Runic, J and Savic, V}, title = {Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans.}, journal = {Bioorganic chemistry}, volume = {87}, number = {}, pages = {209-217}, doi = {10.1016/j.bioorg.2019.03.023}, pmid = {30901676}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects ; Cell Adhesion/drug effects ; Dose-Response Relationship, Drug ; Glycolipids/chemical synthesis/chemistry/*pharmacology ; Lipopeptides/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Peptide Library ; Pseudomonas aeruginosa/drug effects ; Structure-Activity Relationship ; }, abstract = {Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 µg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.}, } @article {pmid30900762, year = {2019}, author = {Velmourougane, K and Prasanna, R and Chawla, G and Nain, L and Kumar, A and Saxena, AK}, title = {Trichoderma-Azotobacter biofilm inoculation improves soil nutrient availability and plant growth in wheat and cotton.}, journal = {Journal of basic microbiology}, volume = {59}, number = {6}, pages = {632-644}, doi = {10.1002/jobm.201900009}, pmid = {30900762}, issn = {1521-4028}, support = {//Indian Council of Agricultural Research (ICAR) Network Project on Microorganisms "Application of Microorganisms in Agricultural and Allied Sectors" (AMAAS)/ ; }, mesh = {Agricultural Inoculants/growth & development/physiology ; Azotobacter/*physiology ; Biofilms/*growth & development ; Biological Availability ; Gossypium/*growth & development/microbiology ; Nutrients/*analysis/pharmacokinetics ; Plant Roots/growth & development/microbiology ; Rhizosphere ; Soil/*chemistry ; Soil Microbiology ; Trichoderma/*physiology ; Triticum/*growth & development/microbiology ; }, abstract = {Microbial biofilms are gaining importance in agriculture, due to their multifaceted agronomic benefits and resilience to environmental fluctuations. This study focuses on comparing the influence of single inoculation-Azotobacter chroococcum (Az) or Trichoderma viride (Tv) and their biofilm (Tv-Az), on soil and plant metabolic activities in wheat and cotton grown under Phytotron conditions. Tv-Az proved superior to all the other treatments in terms of better colonisation, plant growth attributes and 10-40% enhanced availability of macronutrients and micronutrients in the soil, over control. Confocal and scanning electron microscopy showed that the cells attached to the root tips initially, followed by their proliferation along the surface of the roots. Soil polysaccharides, proteins and dehydrogenase activity showed several fold enhancement in Tv-Az biofilm inoculated samples. Time course studies revealed that the population of Az and Tv in the rhizoplane and rhizosphere was significantly higher with a 0.14-0.31 log colony-forming unit (CFU) increase in the biofilm-inoculated treatment in both crops. Enhancement in soil biological activities was facilitated by the improved colonisation of the biofilm, due to the synergistic association between Tv and Az. This demonstrates the utility of Tv-Az biofilm as a multifunctional plant growth promoting and soil fertility enhancing option in agriculture.}, } @article {pmid30895679, year = {2019}, author = {Robinson, VH and Paterson, S and Bennett, C and Steen, SI}, title = {Biofilm production of Pseudomonas spp. isolates from canine otitis in three different enrichment broths.}, journal = {Veterinary dermatology}, volume = {30}, number = {3}, pages = {218-e67}, doi = {10.1111/vde.12738}, pmid = {30895679}, issn = {1365-3164}, support = {//Dechra Veterinary Products, Hadnall, Shropshire, UK/ ; }, mesh = {Animals ; Biofilms/*growth & development ; Caseins/chemistry ; Culture Media/*chemistry ; Dogs ; Microbial Sensitivity Tests ; Otitis/*microbiology ; Protein Hydrolysates/chemistry ; Pseudomonas/*growth & development ; }, abstract = {BACKGROUND: Pseudomonas spp. are commonly isolated from dogs with clinical otitis and have been shown to produce biofilm. There is a paucity of studies demonstrating biofilm growth in veterinary medicine.

HYPOTHESIS/OBJECTIVES: To compare biofilm production of Pseudomonas spp. isolated from dogs with otitis using three different enrichment broths at two different time points. Speciation was performed.

ANIMALS: One hundred isolates from 98 dogs with clinical otitis were assessed for biofilm production.

METHODS AND MATERIALS: One hundred isolates were assessed for biofilm production using a microtitre plate assay. Biofilm production in Luria-Bertani Broth (LBB), Mueller-Hinton Broth (MHB) and Tryptic Soy Broth (TSB) were assessed after 18 and 24 h of incubation.

RESULTS: At 18 h, biofilm production was demonstrated in 87% of LBB, 91% of TSB and 93% of MHB grown isolates. By 24 h, this was 92% of LBB, 96% of TSB and 99% of MHB isolates. Biofilm production was significantly increased after 24 h incubation compared to 18 h. A significant difference was noted in biofilm production between LBB and MHB (P = 0.0349), but not between LBB and TSB (P = 0.3727) or MHB and TSB (P = 0.3687) at 24 h incubation. Two isolates were speciated as P. fluorescens and 98 as P. aeruginosa.

Not all enrichment broths were equivalent to one another and 24 h incubation was superior to 18 h. Biofilm production was high in this population of Pseudomonas spp. isolates.}, } @article {pmid30895659, year = {2019}, author = {Maillard, JY and McBain, A}, title = {Biofilm in healthcare settings and their control.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {268}, doi = {10.1111/lam.13147}, pmid = {30895659}, issn = {1472-765X}, } @article {pmid30895626, year = {2019}, author = {Sterniša, M and Klančnik, A and Smole Možina, S}, title = {Spoilage Pseudomonas biofilm with Escherichia coli protection in fish meat at 5 °C.}, journal = {Journal of the science of food and agriculture}, volume = {99}, number = {10}, pages = {4635-4641}, doi = {10.1002/jsfa.9703}, pmid = {30895626}, issn = {1097-0010}, support = {P4-0116//Slovenian Research Agency/ ; }, mesh = {Animals ; *Biofilms ; Colony Count, Microbial ; Escherichia coli/*growth & development/physiology ; Fishes/*microbiology ; Food Handling ; Food Microbiology ; Pseudomonas/growth & development/*physiology ; Seafood/analysis/*microbiology ; Temperature ; }, abstract = {BACKGROUND: Pseudomonas are part of the indigenous microbiota of different foods, where they gradually cause spoilage. In fish meat, Pseudomonas fragi and Pseudomonas psychrophila have been identified as important spoilers. The initial aim of this study was to investigate the physiological characteristics, adhesion, and biofilm of P. fragi and P. psychrophila under temperatures related to the fish-processing industry. The further aim was to define the problem of increased growth of pathogenic bacteria in the presence of spoilage bacteria in vitro and in fish meat.

RESULTS: Temperature dependence on physiological characteristics, adhesion, and biofilm was observed. Hydrophobicity and autoaggregation were most prominent at 15 °C, and at this temperature floating biofilm was also formed. The adhesion of these Pseudomonas was up to 2 log CFU cm[-1] more pronounced on stainless steel than polystyrene, with up to five times greater biofilm biomass production at 5 °C on polystyrene. This paralleled at least a 0.5 log CFU g[-1] increase in the pathogenic bacterium Escherichia coli in fish meat.

CONCLUSION: Pseudomonas fragi and P. psychrophila adhesion and biofilm depend on the temperature, and are stimulated by temperatures that can occur during the processing and storage of fish meat. Strong Pseudomonas biofilm formation under refrigeration conditions is protective for E. coli, potentially by providing more favorable conditions by ensuring a higher concentration of nutrients. Interactions between spoilage Pseudomonas and pathogenic bacteria can occur through different mechanisms, and an understanding of these is of particular importance to ensure the overall quality and safety of fish meat and other proteinaceous foods. © 2019 Society of Chemical Industry.}, } @article {pmid30894842, year = {2019}, author = {Yang, J and Cheng, S and Li, C and Sun, Y and Huang, H}, title = {Shear Stress Affects Biofilm Structure and Consequently Current Generation of Bioanode in Microbial Electrochemical Systems (MESs).}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {398}, pmid = {30894842}, issn = {1664-302X}, abstract = {Shear stress is an important factor that affects the formation and structure of anode biofilms, which are strongly related to the extracellular electron transfer phenomena and bioelectric performance of bioanodes. Here, we show that using nitrogen sparging to induce shear stress during anode biofilm formation increases the linear sweep voltammetry peak current density of the mature anode biofilm from 2.37 ± 0.15 to 4.05 ± 0.25 A/m[2]. Electrochemical impedance spectroscopy results revealed that the shear-stress-enriched anode biofilm had a low charge transfer resistance of 46.34 Ω compared to that of the unperturbed enriched anode biofilm (72.2 Ω). Confocal laser scanning microscopy observations showed that the shear-stress-enriched biofilms were entirely viable, whereas the unperturbed enriched anode biofilm consisted of a live outer layer covering a dead inner-core layer. Based on biomass and community analyses, the shear-stress-enriched biofilm had four times the biofilm density (136.0 vs. 27.50 μg DNA/cm[3]) and twice the relative abundance of Geobacteraceae (over 80 vs. 40%) in comparison with those of the unperturbed enriched anode biofilm. These results show that applying high shear stress during anode biofilm enrichment can result in an entirely viable and dense biofilm with a high relative abundance of exoelectrogens and, consequently, better performance.}, } @article {pmid30894675, year = {2019}, author = {Zhao, T and Zhang, J and Tang, M and Ma, LZ and Lei, X}, title = {Development of an effective fluorescence probe for discovery of aminopeptidase inhibitors to suppress biofilm formation.}, journal = {The Journal of antibiotics}, volume = {72}, number = {6}, pages = {461-468}, doi = {10.1038/s41429-019-0166-z}, pmid = {30894675}, issn = {1881-1469}, mesh = {Aminopeptidases/*antagonists & inhibitors ; Biofilms/*drug effects ; Drug Discovery ; Enzyme Inhibitors/chemical synthesis/*pharmacology ; Fluorescent Dyes/*chemistry ; Humans ; Pseudomonas aeruginosa/*drug effects/physiology ; Structure-Activity Relationship ; }, abstract = {The human pathogen Pseudomonas aeruginosa can easily form biofilms. The extracellular matrix produced by the bacterial cells acts as a physical barrier to hinder the antibiotics treatment. It is necessary to destroy the biofilm in order to improve the efficacy of antibiotics. However, it has been a significant challenge to develop effective small molecules targeting the components of biofilm matrix. In this study, we report the development of a new effective fluorescence probe that could be used in the high throughput screening to identify novel small molecule inhibitors targeting the most abundant component in the biofilm formation: P. aeruginosa aminopeptidase (PaAP). Through screening of an in-house chemical library, a commercially available drug, balsalazide, has been identified as a novel PaAP inhibitor, which exhibited remarkable anti-biofilm effect. Our study indicated that the newly developed fluorescence probe is applicable in exploring new aminopeptidase inhibitors, and it also warrants further investigation of balsalazide as a new anti-biofilm agent to treat P. aeruginosa infection in combination with known antibiotics.}, } @article {pmid30893371, year = {2019}, author = {Morgan, SJ and Lippman, SI and Bautista, GE and Harrison, JJ and Harding, CL and Gallagher, LA and Cheng, AC and Siehnel, R and Ravishankar, S and Usui, ML and Olerud, JE and Fleckman, P and Wolcott, RD and Manoil, C and Singh, PK}, title = {Bacterial fitness in chronic wounds appears to be mediated by the capacity for high-density growth, not virulence or biofilm functions.}, journal = {PLoS pathogens}, volume = {15}, number = {3}, pages = {e1007511}, pmid = {30893371}, issn = {1553-7374}, support = {R01 AI101307/AI/NIAID NIH HHS/United States ; K24 HL102246/HL/NHLBI NIH HHS/United States ; //Canadian Institutes for Health Research/International ; }, mesh = {Adult ; Animals ; Bacteria/growth & development ; Bacterial Infections/metabolism ; Biofilms/growth & development ; Cell Proliferation/*physiology ; Disease Models, Animal ; Female ; Genetic Fitness ; Host Microbial Interactions/physiology ; Humans ; Male ; Mice ; Pseudomonas Infections ; Pseudomonas aeruginosa/*growth & development/metabolism/pathogenicity ; Virulence/physiology ; Wound Healing/*physiology ; Wound Infection/metabolism/microbiology ; }, abstract = {While much is known about acute infection pathogenesis, the understanding of chronic infections has lagged. Here we sought to identify the genes and functions that mediate fitness of the pathogen Pseudomonas aeruginosa in chronic wound infections, and to better understand the selective environment in wounds. We found that clinical isolates from chronic human wounds were frequently defective in virulence functions and biofilm formation, and that many virulence and biofilm formation genes were not required for bacterial fitness in experimental mouse wounds. In contrast, genes involved in anaerobic growth, some metabolic and energy pathways, and membrane integrity were critical. Consistent with these findings, the fitness characteristics of some wound impaired-mutants could be represented by anaerobic, oxidative, and membrane-stress conditions ex vivo, and more comprehensively by high-density bacterial growth conditions, in the absence of a host. These data shed light on the bacterial functions needed in chronic wound infections, the nature of stresses applied to bacteria at chronic infection sites, and suggest therapeutic targets that might compromise wound infection pathogenesis.}, } @article {pmid30891135, year = {2019}, author = {Zhang, J and Huang, H and Zhou, X and Xu, Y and Chen, B and Tang, W and Xu, K}, title = {N-Benzylanilines as Fatty Acid Synthesis Inhibitors against Biofilm-related Methicillin-resistant Staphylococcus aureus.}, journal = {ACS medicinal chemistry letters}, volume = {10}, number = {3}, pages = {329-333}, pmid = {30891135}, issn = {1948-5875}, abstract = {Bacterial fatty acid synthase system is a well validated target for the development of novel antimicrobial agents. This study reports the synthesis of Schiff bases and their reductive N-benzylanilines. Most N-benzylanilines were active against Gram-positive bacteria, among which compound 4k performed best against both S. aureus and MRSA with the MIC value at 0.5 mg/L. Moreover, we identified the strong antibacterial activity for compound 4k against 19 clinical MRSA strains isolated from different specimen, which indicated its potential in clinical application. In vitro biofilm inhibition and microscopy assay revealed compound 4k inhibits biofilm formation and eradicates preformed biofilm effectively. The size-exclusion chromatography and docking study indicated that compound 4k mimics the binding mode of triclosan with saFabI. The efficiency of the protein-inhibitor interaction was evaluated by measuring NADPH reduction using trans-2-octenoyl-CoA as substrate. Overall, our data demonstrate that N-benzylaniline is a promising scaffold for anti-staphylococcal drug development.}, } @article {pmid30891026, year = {2019}, author = {Sigurlásdóttir, S and Wassing, GM and Zuo, F and Arts, M and Jonsson, AB}, title = {Deletion of D-Lactate Dehydrogenase A in Neisseria meningitidis Promotes Biofilm Formation Through Increased Autolysis and Extracellular DNA Release.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {422}, pmid = {30891026}, issn = {1664-302X}, abstract = {Neisseria meningitidis is a Gram-negative bacterium that asymptomatically colonizes the human nasopharyngeal mucosa. Pilus-mediated initial adherence of N. meningitidis to the epithelial mucosa is followed by the formation of three-dimensional aggregates, called microcolonies. Dispersal from microcolonies contributes to the transmission of N. meningitidis across the epithelial mucosa. We have recently discovered that environmental concentrations of host cell-derived lactate influences N. meningitidis microcolony dispersal. Here, we examined the ability of N. meningitidis mutants deficient in lactate metabolism to form biofilms. A lactate dehydrogenease A (ldhA) mutant had an increased level of biofilm formation. Deletion of ldhA increased the N. meningitidis cell surface hydrophobicity and aggregation. In this study, we used FAM20, which belongs to clonal complex ST-11 that forms biofilms independently of extracellular DNA (eDNA). However, treatment with DNase I abolished the increased biofilm formation and aggregation of the ldhA-deficient mutant, suggesting a critical role for eDNA. Compared to wild-type, the ldhA-deficient mutant exhibited an increased autolytic rate, with significant increases in the eDNA concentrations in the culture supernatants and in biofilms. Within the ldhA mutant biofilm, the transcription levels of the capsule, pilus, and bacterial lysis genes were downregulated, while norB, which is associated with anaerobic respiration, was upregulated. These findings suggest that the absence of ldhA in N. meningitidis promotes biofilm formation and aggregation through autolysis-mediated DNA release.}, } @article {pmid30888063, year = {2019}, author = {Mostafavi, SKS and Najar-Peerayeh, S and Mobarez, AM and Parizi, MK}, title = {Characterization of uropathogenic E. coli O25b-B2-ST131, O15:K52:H1, and CGA: Neutrophils apoptosis, serum bactericidal assay, biofilm formation, and virulence typing.}, journal = {Journal of cellular physiology}, volume = {234}, number = {10}, pages = {18272-18282}, doi = {10.1002/jcp.28459}, pmid = {30888063}, issn = {1097-4652}, mesh = {Anti-Bacterial Agents/pharmacology ; Apoptosis/drug effects/*genetics ; Biofilms/drug effects/*growth & development ; Escherichia coli Infections/drug therapy/microbiology ; Genotype ; Humans ; Neutrophils/drug effects/*physiology ; Serotyping/methods ; Uropathogenic Escherichia coli/drug effects/*genetics ; Virulence/drug effects/*genetics ; Virulence Factors/*genetics ; }, abstract = {Pathogenic and drug-resistant strains of Escherichia coli (E. coli) O25b-B2-ST131, O15:H1-D-ST393, and CGA (clonal group A) clonal groups have spread worldwide. This study aimed at determining E. coli epidemic clonal groups, their virulence factors, biofilm formation, neutrophils apoptosis, and antimicrobial resistance pattern of uropathogenic E. coli. A total of 95 CTX-M-1-producing E. coli clinical isolates were enrolled. E. coli O25b-B2-ST131, CGA, and O15:K52:H1 were identified by serotyping and phylogrouping and allele-specific polymerase chain reaction-based assay. Antibiotic susceptibility, biofilm formation, hemolysis, and human serum bactericidal assay were performed. Neutrophil apoptosis was assayed by flow cytometry. Nine E. coli clonal groups including six O25b-B2-ST131 strains, two CGA, and one O15:K52:H1-D-ST393 strains were detected. One O25b-B2-ST131 isolate was a strong biofilm-producer. Three ST131 isolates had type I fimbriae. Furthermore, all the CGA and O15:K52:H1 and three of ST131 isolates harbored the P fimbriae. The virulence genes ompT, fimH, and traT were detected among all the clonal groups. The apoptosis was induced by O25b-B2-ST131, CGA, and O15:K52:H1 E. coli. There was no significant difference regarding apoptosis induction among clonal groups. Furthermore, the presence of the cdt, usp, and vat genes was significantly associated with the apoptosis of neutrophils by O25b-B2-ST131, CGA, and O15:K52:H1-D-ST393 clonal groups.}, } @article {pmid30887260, year = {2019}, author = {Rajamohamed, BS and Siddharthan, S}, title = {Modulatory effects of Amukkara Choornam on Candida albicans biofilm: in vitro and in vivo study.}, journal = {Molecular biology reports}, volume = {46}, number = {3}, pages = {2961-2969}, pmid = {30887260}, issn = {1573-4978}, support = {YSS/20l4/000127//Science and Engineering Research Board/ ; }, mesh = {Animals ; Biofilms/drug effects ; Candida albicans/*drug effects ; Herbal Medicine/methods ; Plant Extracts/*pharmacology ; Virulence ; Withania/*chemistry/metabolism/physiology ; Zebrafish/microbiology ; }, abstract = {In the present study, Amukkara Chooram (AC) a well known herbal medicine was investigated for their antibiofilm efficacy against biofilm of Candida albicans. The biofilm inhibitory concentration of 20 µg/mL of AC showed promising effect by inhibiting the biofilm upto 60%. Morphogenic transition state of C. albicans from yeast cells to hyphal transition was prevented by AC was revealed from light microscopic images. In addition, the inhibition of yeast hyphae was examined in the induction medium supplemented with AC. Consequently, atomic force microscope (AFM) also documented the morphological changes observed during the transition state of C. albicans in the presence and absence of AC. Furthermore, scanning electron microscope (SEM) and confocal laser scanning microscopic (CLSM) images showed reduction in the biomass and thickness of the mature biofilm of C. albicans. In vivo investigation of C. albicans with zebrafish infection model presented the clearance of biofilm from the epithelium of the intestinal tissues. Later, the histological changes in liver and kidney due to C. albicans infection open up that treatment with AC was able to significantly rejuvenate the tissues. Altogether, the study presents AC as potent antibiofilm agent with potential ability as alternative medicine to treat C. albicans biofilm mediated infections.}, } @article {pmid30887082, year = {2019}, author = {Ciszek-Lenda, M and Strus, M and Walczewska, M and Majka, G and Machul-Żwirbla, A and Mikołajczyk, D and Górska, S and Gamian, A and Chain, B and Marcinkiewicz, J}, title = {Pseudomonas aeruginosa biofilm is a potent inducer of phagocyte hyperinflammation.}, journal = {Inflammation research : official journal of the European Histamine Research Society ... [et al.]}, volume = {68}, number = {5}, pages = {397-413}, pmid = {30887082}, issn = {1420-908X}, support = {2017/27/B/NZ6/001772//Narodowe Centrum Nauki/ ; NN401547040//Narodowe Centrum Nauki/ ; }, mesh = {Animals ; *Biofilms ; Cells, Cultured ; Cytokines/immunology ; DNA, Bacterial ; Inflammation/immunology ; Lipopolysaccharides ; Macrophages/*immunology ; Mice, Inbred CBA ; Neutrophils/*immunology ; Polysaccharides, Bacterial/physiology ; Pseudomonas aeruginosa/*physiology ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa effectively facilitate resistance to phagocyte killing by biofilm formation. However, the cross talk between biofilm components and phagocytes is still unclear. We hypothesize that a biofilm provides a concentrated extracellular source of LPS, DNA and exopolysaccharides (EPS), which polarize neighbouring phagocytes into an adverse hyperinflammatory state of activation.

METHODS: We measured the release of a panel of mediators produced in vitro by murine neutrophils and macrophages exposed to various biofilm components of P. aeruginosa cultures.

RESULTS: We found that conditioned media from a high biofilm-producing strain of P. aeruginosa, PAR5, accumulated high concentrations of extracellular bacterial LPS, DNA and EPS by 72 h. These conditioned media induced phagocytes to release a hyperinflammatory pattern of mediators, with enhanced levels of TNF-α, IL-6, IL12p40, PGE2 and NO. Moreover, the phagocytes also upregulated COX-2 and iNOS with no influence on the expression of arginase-1.

CONCLUSIONS: Phagocytes exposed to biofilm microenvironment, called by us biofilm-associated neutrophils/macrophages (BANs/BAMs), display secretory properties similar to that of N1/M1-type phagocytes. These results suggest that in vivo high concentrations of LPS and DNA, trapped in biofilm by EPS, might convert infiltrating phagocytes into cells responsible for tissue injury without direct contact with bacteria and phagocytosis.}, } @article {pmid30886729, year = {2019}, author = {Okaro, U and Green, R and Mohapatra, S and Anderson, B}, title = {The trimeric autotransporter adhesin BadA is required for in vitro biofilm formation by Bartonella henselae.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {10}, pmid = {30886729}, issn = {2055-5008}, support = {IK6 BX004212/BX/BLRD VA/United States ; }, mesh = {*Bacterial Adhesion ; Bacterial Proteins/*metabolism ; Bartonella henselae/genetics/*growth & development/radiation effects ; Biofilms/*growth & development/radiation effects ; Gene Deletion ; Genetic Complementation Test ; Hydrogen-Ion Concentration ; Temperature ; Virulence Factors/deficiency/*metabolism ; }, abstract = {Bartonella henselae (Bh) is a Gram-negative rod transmitted to humans by a scratch from the common house cat. Infection of humans with Bh can result in a range of clinical diseases including lymphadenopathy observed in cat-scratch disease and more serious disease from persistent bacteremia. It is a common cause of blood-culture negative endocarditis as the bacterium is capable of growing as aggregates, and forming biofilms on infected native and prosthetic heart valves. The aggregative growth requires a trimeric autotransporter adhesin (TAA) called Bartonella adhesin A (BadA). TAAs are found in all Bartonella species and many other Gram-negative bacteria. Using Bh Houston-1, Bh Houston-1 ∆badA and Bh Houston-1 ∆badA/pNS2PTrc badA (a partial complement of badA coding for a truncated protein of 741 amino acid residues), we analyze the role of BadA in adhesion and biofilm formation. We also investigate the role of environmental factors such as temperature on badA expression and biofilm formation. Real-time cell adhesion monitoring and electron microscopy show that Bh Houston-1 adheres and forms biofilm more efficiently than the Bh Houston-1 ∆badA. Deletion of the badA gene significantly decreases adhesion, the first step in biofilm formation in vitro, which is partially restored in Bh Houston-1 ∆badA/pNS2PTrc badA. The biofilm formed by Bh Houston-1 includes polysaccharides, proteins, and DNA components and is susceptible to enzymatic degradation of these components. Furthermore, both pH and temperature influence both badA expression and biofilm formation. We conclude that BadA is required for optimal adhesion, agglutination and biofilm formation.}, } @article {pmid30886318, year = {2019}, author = {Brislawn, CJ and Graham, EB and Dana, K and Ihardt, P and Fansler, SJ and Chrisler, WB and Cliff, JB and Stegen, JC and Moran, JJ and Bernstein, HC}, title = {Forfeiting the priority effect: turnover defines biofilm community succession.}, journal = {The ISME journal}, volume = {13}, number = {7}, pages = {1865-1877}, pmid = {30886318}, issn = {1751-7370}, mesh = {Bacteria/*classification/genetics ; *Biofilms ; Ecology ; *Microbiota ; Stochastic Processes ; }, abstract = {Microbial community succession is a fundamental process that affects underlying functions of almost all ecosystems; yet the roles and fates of the most abundant colonizers are often poorly understood. Does early abundance spur long term persistence? How do deterministic and stochastic processes influence the ecological contribution of colonizers? We performed a succession experiment within a hypersaline ecosystem to investigate how different processes contributed to the turnover of founder species. Bacterial and eukaryotic colonizers were identified during primary succession and tracked through a defined, 79-day biofilm maturation period using 16S and 18S rRNA gene sequencing in combination with high resolution imaging that utilized stable isotope tracers to evaluate successional patterns of primary producers and nitrogen fixers. The majority of the founder species did not maintain high abundance throughout succession. Species replacement (versus loss) was the dominant process shaping community succession. We also asked if different ecological processes acted on bacteria versus Eukaryotes during succession and found deterministic and stochastic forces corresponded more with microeukaryote and bacterial colonization, respectively. Our results show that taxa and functions belonging to different kingdoms, which share habitat in the tight spatial confines of a biofilm, were influenced by different ecological processes and time scales of succession.}, } @article {pmid30886168, year = {2019}, author = {Nakamura, K and Shirato, M and Tenkumo, T and Kanno, T and Westerlund, A and Örtengren, U and Sasaki, K and Niwano, Y}, title = {Hydroxyl radicals generated by hydrogen peroxide photolysis recondition biofilm-contaminated titanium surfaces for subsequent osteoblastic cell proliferation.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {4688}, pmid = {30886168}, issn = {2045-2322}, mesh = {Alveolar Bone Loss/*prevention & control ; Animals ; Anti-Infective Agents/*therapeutic use ; Biofilms ; Biological Therapy/*methods ; Cell Line ; Cell Proliferation ; Dental Implantation/*methods ; Dental Implants/*microbiology ; Humans ; Hydrogen Peroxide/chemistry/metabolism/*therapeutic use ; Hydroxyl Radical/*metabolism ; Mice ; Osteoblasts/*physiology ; Peri-Implantitis/*therapy ; Photolysis ; Titanium/*chemistry ; }, abstract = {Titanium dental implants have been successfully used for decades; however, some implants are affected by peri-implantitis due to bacterial infection, resulting in loss of supporting bone. This study aimed to evaluate the effect of an antimicrobial chemotherapy employing H2O2 photolysis-developed to treat peri-implantitis-on biofilm-contaminated titanium surfaces in association with osteoblastic cell proliferation on the treated surface. Titanium discs were sandblasted and acid-etched, followed by contamination with a three-species biofilm composed of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mitis. This biofilm model was used as a simplified model of clinical peri-implantitis biofilm. The discs were subjected to ultrasound scaling, followed by H2O2 photolysis, wherein 365-nm LED irradiation of the disc immersed in 3% H2O2 was performed for 5 min. We analysed proliferation of mouse osteoblastic cells (MC3T3-E1) cultured on the treated discs. Compared with intact discs, biofilm contamination lowered cell proliferation on the specimen surface, whereas H2O2 photolysis recovered cell proliferation. Thus, H2O2 photolysis can recover the degraded biocompatibility of biofilm-contaminated titanium surfaces and can potentially be utilised for peri-implantitis treatment. However, to verify the findings of this study in relation to clinical settings, assessment using a more clinically relevant multi-species biofilm model is necessary.}, } @article {pmid30885396, year = {2019}, author = {Ferreira, RBR and Ferreira, MCS and Glatthardt, T and Silvério, MP and Chamon, RC and Salgueiro, VC and Guimarães, LC and Alves, ES and Dos Santos, KRN}, title = {Osmotic stress induces biofilm production by Staphylococcus epidermidis isolates from neonates.}, journal = {Diagnostic microbiology and infectious disease}, volume = {94}, number = {4}, pages = {337-341}, doi = {10.1016/j.diagmicrobio.2019.02.009}, pmid = {30885396}, issn = {1879-0070}, mesh = {Biofilms/drug effects/*growth & development ; Culture Media/chemistry ; DNA, Bacterial/genetics ; Gene Expression ; Glucose/pharmacology ; Humans ; Infant, Newborn ; *Osmotic Pressure ; Phenotype ; Sodium Chloride/pharmacology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/drug effects/*physiology ; }, abstract = {Staphylococcus epidermidis is one of the leading causes of bloodstream infections, particularly in premature neonates, and biofilm formation is a major virulence factor. We characterized biofilm formation by 50 S. epidermidis neonatal isolates under osmotic stress and evaluated the expression of biofilm-associated genes. Phenotypical analyses of biofilm production were performed in culture medium with or without addition of NaCl or glucose. In control medium (no additions), most isolates (84%) were nonproducers or weak biofilm producers. Growth in NaCl-containing medium increased the number of moderate/strong producers, and this increase was even greater in medium containing glucose. Most of the protein-enriched biofilms (60%) could be observed only during growth in glucose, whereas 50% of the polysaccharide-enriched biofilms were observed during growth in NaCl. Studies that evaluate the conditions used to characterize biofilm production are important to help us understand the dynamics of this important virulence factor in S. epidermidis and their impact on neonatal infections.}, } @article {pmid30884970, year = {2019}, author = {Sadiq, FA and Flint, S and Sakandar, HA and He, G}, title = {Molecular regulation of adhesion and biofilm formation in high and low biofilm producers of Bacillus licheniformis using RNA-Seq.}, journal = {Biofouling}, volume = {35}, number = {2}, pages = {143-158}, doi = {10.1080/08927014.2019.1575960}, pmid = {30884970}, issn = {1029-2454}, mesh = {Animals ; Bacillus licheniformis/genetics/*isolation & purification ; Biofilms/*growth & development ; China ; Food Microbiology ; Gene Expression Profiling ; Milk/microbiology ; RNA, Bacterial/*isolation & purification ; Sequence Analysis, RNA ; Transcriptome ; }, abstract = {RNA sequencing was used to reveal transcriptional changes during the motile-to-sessile switch in high and low biofilm-forming dairy strains of B. licheniformis isolated from Chinese milk powders. A significant part of the whole gene content was affected during this transition in both strains. In terms of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, seven metabolic pathways were significantly downregulated in the planktonic state compared to the biofilm state in both strains. Lipid and sugar metabolism seemed to play an important role in matrix production. Several genes involved in adhesion, matrix production and the matrix coating were either absent or less expressed in the biofilm state of the low biofilm producer compared to the high biofilm producer. Genes related to sporulation and the production of extracellular polymeric substances were concomitantly expressed in the biofilm state of both strains. These comprehensive insights will be helpful for future research into mechanisms and targets.}, } @article {pmid30884874, year = {2019}, author = {Trotsko, N and Kosikowska, U and Andrzejczuk, S and Paneth, A and Wujec, M}, title = {Influence of Thiazolidine-2,4-Dione Derivatives with Azolidine or Thiosemicarbazone Moieties on Haemophilus spp. Planktonic or Biofilm-Forming Cells.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {6}, pages = {}, pmid = {30884874}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Gram-Negative Bacteria/drug effects/pathogenicity ; Haemophilus/*drug effects/growth & development ; Microbial Sensitivity Tests ; Plankton/drug effects ; Thiazolidinediones/chemistry/pharmacology ; Thiosemicarbazones/*chemistry/pharmacology ; }, abstract = {Biofilm, naturally formed by microorganisms as integrated surface-bound communities, is one of the reasons for the development of antimicrobial resistance. Haemophilus spp. are common and representative opportunistic Gram-negative rods forming from the upper respiratory tract microbiota. The aim of this paper was to evaluate the influence of thiazolidine-2,4-dionebased azolidine and chlorophenylthiosemicarbazone hybrids against both planktonic and biofilm-forming Haemophilus spp. cells. The in vitro activity against planktonic and biofilm-forming cells of the tested compounds were evaluated by using the broth microdilution method. These activities were detected against reference and clinical strains of Haemophilus spp. on the basis of MICs (minimal inhibitory concentrations) and MBICs (minimal biofilm inhibitory concentrations). In addition, anti-adhesive properties of these compounds were examined. The target compounds showed potential activity against planktonic cells with MIC = 62.5[-]500 mg/L and biofilm-forming cells with MBIC = 62.5[-]1000 mg/L. The observed anti-adhesive properties of the tested compounds were reversible during long-term incubation in a lower concentration of compounds.}, } @article {pmid30884686, year = {2019}, author = {Merino, L and Procura, F and Trejo, FM and Bueno, DJ and Golowczyc, MA}, title = {Biofilm formation by Salmonella sp. in the poultry industry: Detection, control and eradication strategies.}, journal = {Food research international (Ottawa, Ont.)}, volume = {119}, number = {}, pages = {530-540}, doi = {10.1016/j.foodres.2017.11.024}, pmid = {30884686}, issn = {1873-7145}, mesh = {Animals ; Bacteria ; Bacteriocins/pharmacology ; Biofilms/*drug effects/*growth & development ; Farms ; Food Contamination/prevention & control ; Food Handling/methods ; *Food Industry ; *Food Microbiology ; Foodborne Diseases/microbiology/prevention & control ; Humans ; Lactobacillales/physiology ; Nanostructures ; Phage Therapy ; Plant Extracts/pharmacology ; Poultry/*microbiology ; Quorum Sensing/drug effects ; Salmonella/drug effects/*metabolism ; Salmonella Infections/microbiology/prevention & control ; }, abstract = {Salmonella represents an important global public health problem and it is an emerging zoonotic bacterial threat in the poultry industry. Diverse registered human cases of salmonellosis shown poultry origins. Various control measures have been employed both at the farming and processing levels to address it. This review focuses on traditional and new detection techniques of biofilm formation by Salmonella spp. and different approaches that can be used to prevent and/or control biofilm formation by these bacteria. A number of methodologies based on different approximations have been recently employed to detect and evaluate bacteria attached to surfaces, including real-time polymerase chain reaction (PCR), confocal laser scanning microscopy and Optical Coherence Tomography. Due to persistence of Salmonella biofilm in food processing environments after cleaning and sanitation, control and eradication strategies in poultry industry should be constantly studied. In this sense, the use of several alternatives to control Salmonella biofilm formation, such as lactic acid bacteria, phagetherapy, extracts from aromatic plants, quorum sensing inhibitors, bacteriocins and nanomaterials, have been successfully tested and will be reviewed.}, } @article {pmid30884454, year = {2019}, author = {Del Rio, M and de la Canal, L and Pinedo, M and Mora-Montes, HM and Regente, M}, title = {Effects of the binding of a Helianthus annuus lectin to Candida albicans cell wall on biofilm development and adhesion to host cells.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {58}, number = {}, pages = {152875}, doi = {10.1016/j.phymed.2019.152875}, pmid = {30884454}, issn = {1618-095X}, mesh = {Antifungal Agents/*metabolism/pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/pathogenicity/physiology ; Cell Membrane/chemistry/drug effects ; Cell Wall/drug effects/metabolism ; Cells, Cultured ; Epithelial Cells/microbiology ; Fluorescein-5-isothiocyanate/chemistry/metabolism ; Helianthus/*chemistry ; Humans ; Hydrogen Peroxide/metabolism ; Hydrophobic and Hydrophilic Interactions ; Plant Lectins/*metabolism/*pharmacology ; }, abstract = {BACKGROUND: In our previous study, we isolated and characterized a lectin called Helja from Helianthus annuus (sunflower) and then, in a further study, demonstrated its antifungal activity against Candida spp. Since Candida infections are a major health concern due to the increasing emergence of antifungal resistant strains, the search for new antifungal agents offers a promising opportunity for improving the treatment strategies against candidiasis.

PURPOSE: The aim of this work was to get insights about the mechanism of action of Helja, an antifungal lectin of H. annuus, and to explore its ability to inhibit Candida albicans biofilm development and adherence to buccal epithelial cells (BEC).

STUDY DESIGN/METHODS: Yeast viability was evaluated by Evans Blue uptake and counting of colony forming units (CFU). The yeast cell integrity was assessed using Calcofluor White (CFW) as a cell wall perturbing agent and sorbitol as osmotic protectant. The induction of oxidative stress was evaluated using 3,3'-diaminobenzidine (DAB) for detection of hydrogen peroxide. The adherence was determined by counting the yeast cells attached to BEC after methylene blue staining. The biofilms were developed on polystyrene microplates, visualized by confocal laser scanning microscopy and the viable biomass was quantified by CFU counting. The binding lectin-Candida was assessed using Helja conjugated to fluorescein isothiocyanate (Helja-FITC) and simultaneous staining with CFW. The cellular surface hydrophobicity (CSH) was determined using a microbial adhesion to hydrocarbons method.

RESULTS: C. albicans cells treated with 0.1 µg/µl of Helja showed a drastic decrease in yeast survival. The lectin affected the fungal cell integrity, induced the production of hydrogen peroxide and inhibited the morphological transition from yeast to filamentous forms. Helja caused a significant reduction of adherent cells and a decrease in biofilm biomass and coverage area. The treatment with the protein also reduced the surface hydrophobicity of fungal cells. We show the binding of Helja-FITC to yeast cells distributed as a thin outer layer to the CFW signal, and this interaction was displaced by mannose and Concanavalin A.

CONCLUSION: The results demonstrate the interaction of Helja with the mannoproteins of C. albicans cell wall, the disruption of the cell integrity, the induction of oxidative stress, the inhibition of the morphological transition from yeast to filamentous forms and the fungal cell viability loss. The binding Helja-Candida also provides a possible explanation of the lectin effect on cell adherence, biofilm development and CSH, relevant features related to virulence of the pathogen.}, } @article {pmid30884254, year = {2019}, author = {Tang, R and Zhu, J and Feng, L and Li, J and Liu, X}, title = {Characterization of LuxI/LuxR and their regulation involved in biofilm formation and stress resistance in fish spoilers Pseudomonas fluorescens.}, journal = {International journal of food microbiology}, volume = {297}, number = {}, pages = {60-71}, doi = {10.1016/j.ijfoodmicro.2018.12.011}, pmid = {30884254}, issn = {1879-3460}, mesh = {4-Butyrolactone/analogs & derivatives ; Animals ; *Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Fishes/microbiology ; Gene Expression Regulation, Bacterial ; Pseudomonas fluorescens/genetics/*physiology ; *Repressor Proteins/genetics/metabolism ; Seafood/*microbiology ; Sequence Deletion ; Stress, Physiological/*genetics ; *Trans-Activators/genetics/metabolism ; *Transcription Factors/genetics/metabolism ; }, abstract = {Quorum sensing (QS) is crucial for adaption and development of foodborne bacteria in diverse environments. Pseudomonas fluorescens PF07 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study AHL-mediated QS system was characterized and their roles in biofilm formation, motility, stress response and spoilage of P. fluorescens were evaluated. A LuxI/LuxR homolog consisting of a conserved AHL synthase gene (luxI) and a transcriptional regulator gene (luxR) was identified in the strain. Two in-frame deletion mutants of luxI and luxR, ∆luxI and ∆luxR, were constructed to explore their QS signaling function in P. fluorescens. Three types of AHLs were detected in PF07 culture by LC-MS/MS, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule. The C4-HSL activities was almost abolished in ∆luxI, and decreased greatly in ∆luxR. Compared with wild type (WT) strain, both ∆luxI and ∆luxR showed the significant decrease of biofilm biomass and expolysaccharide production, resulting in thinner and incompact biofilm structure, but promoted swimming motility. The resistance of P. fluorescens to H2O2, heat, NaCl and crystal violet apparently declined in two mutants compared to WT. Spoilage factors, siderophore and protease, apparently attenuated due to deletion of luxI or luxR gene, while the growth and TVB-N production did not differ. Furthermore, the changes of the biofilm formation, motility and protease in ∆luxI strain were partially restored by the exogenous C4-HSL. In agreement with the effect of two mutants on various phenotypes, the transcriptions of alg, lapA, flgA, rpoS, and aprX were significantly down-regulated, and flgA was up-regulated in ∆luxI and ∆luxR. Therefore, the present study highlighted that the co-operation of LuxI/LuxR homolog was an important QS regulator in biofilm formation, motility and spoilage potential, and hinted its positive regulation of stress resistance with RpoS in P. fluorescens.}, } @article {pmid30883044, year = {2019}, author = {Percival, SL and Mayer, D and Kirsner, RS and Schultz, G and Weir, D and Roy, S and Alavi, A and Romanelli, M}, title = {Surfactants: Role in biofilm management and cellular behaviour.}, journal = {International wound journal}, volume = {16}, number = {3}, pages = {753-760}, pmid = {30883044}, issn = {1742-481X}, support = {//Medline Industries Inc/ ; }, mesh = {Biofilms/*drug effects ; Cell Enlargement/*drug effects ; Cell Proliferation/*drug effects ; Disinfectants/*therapeutic use ; Humans ; Surface-Active Agents/*therapeutic use ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {Appropriate and effective wound cleaning represents an important process that is necessary for preparing the wound for improved wound healing and for helping to dislodge biofilms. Wound cleaning is of paramount importance to wound bed preparation for helping to enhance wound healing. Surfactant applications in wound care may represent an important area in the cleaning continuum. However, understanding of the role and significance of surfactants in wound cleansing, biofilm prevention and control, and enhancing cellular viability and proliferation is currently lacking. Despite this, some recent evidence on poloxamer-based surfactants where the surfactants are present in high concentration have been shown to have an important role to play in biofilm management; matrix metalloproteinase modulation; reducing inflammation; and enhancing cellular proliferation, behaviour, and viability. Consequently, this review aims to discuss the role, mode of action, and clinical significance of the use of medically accepted surfactants, with a focus on concentrated poloxamer-based surfactants, to wound healing but, more specifically, the role they may play in biofilm management and effects on cellular repair.}, } @article {pmid30883023, year = {2020}, author = {Junka, A and Bartoszewicz, M and Dziadas, M and Szymczyk, P and Dydak, K and Żywicka, A and Owczarek, A and Bil-Lula, I and Czajkowska, J and Fijałkowski, K}, title = {Application of bacterial cellulose experimental dressings saturated with gentamycin for management of bone biofilm in vitro and ex vivo.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {108}, number = {1}, pages = {30-37}, doi = {10.1002/jbm.b.34362}, pmid = {30883023}, issn = {1552-4981}, mesh = {Animals ; *Bandages ; Biofilms/*drug effects/growth & development ; Cell Line ; Cellulose/*chemistry ; Femur/metabolism/*microbiology ; *Gentamicins/chemistry/pharmacokinetics/pharmacology ; Humans ; Osteoblasts/metabolism/*microbiology ; Pseudomonas aeruginosa/*physiology ; Rats ; Staphylococcus aureus/*physiology ; }, abstract = {Bacterial cellulose is one of the most promising polymers of recent years. Herein, we present a possibility of BC application as a carrier of gentamycin antibiotic for the treatment and prevention of bone infections. We have shown that BC saturated with gentamycin significantly reduces the level of biofilm-forming bone pathogens, namely Staphylococcus aureus and Pseudomonas aeruginosa, and displays very low cytotoxicity in vitro against osteoblast cell cultures. Another beneficial feature of our prototype dressing is prolonged release of gentamycin, which provides efficient protection from microbial contamination and subsequent infection. Moreover, it seems that bacterial cellulose (BC) alone without any antimicrobial added, may serve as a barrier by significantly hampering the ability of the pathogen to penetrate to the bone structure. Therefore, a gentamycin-saturated BC dressing may be considered as a possible alternative for gentamycin collagen sponge broadly used in clinical setting. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:30-37, 2020.}, } @article {pmid30882296, year = {2019}, author = {Luo, TL and Hayashi, M and Zsiska, M and Circello, B and Eisenberg, M and Gonzalez-Cabezas, C and Foxman, B and Marrs, CF and Rickard, AH}, title = {Introducing BAIT (Biofilm Architecture Inference Tool): a software program to evaluate the architecture of oral multi-species biofilms.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {5}, pages = {527-537}, doi = {10.1099/mic.0.000761}, pmid = {30882296}, issn = {1465-2080}, support = {R01 DE014899/DE/NIDCR NIH HHS/United States ; }, mesh = {Algorithms ; Anti-Bacterial Agents/pharmacology ; Bacteria/classification/drug effects/isolation & purification ; Bacterial Physiological Phenomena ; Bacteriological Techniques/instrumentation/methods ; *Biofilms/drug effects ; Humans ; Image Processing, Computer-Assisted/instrumentation/*methods ; Microbial Viability/drug effects ; Mouth/*microbiology ; Saliva/microbiology ; *Software ; Tin Fluorides/pharmacology ; }, abstract = {Biofilm model systems are used to study biofilm growth and predict the effects of anti-biofilm interventions within the human oral cavity. Many in vitro biofilm model systems use a confocal laser scanning microscope (CLSM) in conjunction with image analysis tools to study biofilms. The aim of this study was to evaluate an in-house developed image analysis software program that we call BAIT (Biofilm Architecture Inference Tool) to quantify the architecture of oral multi-species biofilms following anti-biofilm interventions using a microfluidic biofilm system. Differences in architecture were compared between untreated biofilms and those treated with water (negative control), sodium gluconate ('placebo') or stannous fluoride (SnF2). The microfluidic system was inoculated with pooled human saliva and biofilms were developed over 22 h in filter-sterilized 25 % pooled human saliva. During this period, biofilms were treated with water, sodium gluconate, or SnF2 (1000, 3439 or 10 000 p.p.m. Sn[2+]) 8 and 18 h post-inoculation. After 22 h of growth, biofilms were stained with LIVE/DEAD stain, and imaged by CLSM. BAIT was used to calculate biofilm biovolume, total number of objects, surface area, fluffiness, connectivity, convex hull porosity and viability. Image analysis showed oral biofilm architecture was significantly altered by 3439 and 10 000 p.p.m. Sn[2+] treatment regimens, resulting in decreased biovolume, surface area, number of objects and connectivity, while fluffiness increased (P<0.01). In conclusion, BAIT was shown to be able to measure the changes in biofilm architecture and detects possible antimicrobial and anti-biofilm effects of candidate agents.}, } @article {pmid30881988, year = {2019}, author = {Pate, M and Mičunovič, J and Golob, M and Vestby, LK and Ocepek, M}, title = {Salmonella Infantis in Broiler Flocks in Slovenia: The Prevalence of Multidrug Resistant Strains with High Genetic Homogeneity and Low Biofilm-Forming Ability.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {4981463}, pmid = {30881988}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/adverse effects ; Biofilms/*drug effects ; Chickens/microbiology ; Drug Resistance, Multiple, Bacterial ; Feces/microbiology ; Genetic Variation ; Humans ; Microbial Sensitivity Tests ; Poultry Diseases/*drug therapy/microbiology/pathology ; Salmonella Infections, Animal/*drug therapy/microbiology/pathology ; Serogroup ; Slovenia ; }, abstract = {For almost a decade, the number of Salmonella enterica subspecies enterica serovar Infantis-positive broiler flocks has been steadily increasing in Slovenia, doubling the number of positive holdings in only a few years. Since multidrug resistant S. Infantis isolates are highly prevalent in the broiler meat industry and may represent a public health concern through the food chain, we aimed to investigate the antimicrobial susceptibility, genetic diversity, and biofilm-forming ability of S. Infantis from Slovenian broiler flocks. A total of 87 S. Infantis strains isolated from broiler faeces in the period between 2007 and 2013 were studied. The samples originated from 41 farms which were subcontractors of three major food business operators and from two autonomously operating holdings (farms). Isolates were phenotypically tested for their susceptibility to 14 antimicrobials from nine classes by determining the minimum inhibitory concentration with the microdilution method. Only 8% of the isolates were susceptible to all of the antimicrobial agents tested, while 88.5% of the isolates were multidrug resistant, with the most common resistance pattern CipNxSSuT (65.5%) followed by CipNxSuT (17.2%). Pulsed-field gel electrophoresis (PFGE) divided the strains into five clusters (A-E) comprising 16 distinct XbaI PFGE profiles. Sixty-five out of 87 isolates were grouped in clusters A and B, with the predominant PFGE profiles A1 and B1 encompassing 33 and 28 isolates, respectively. A vast majority of the isolates (75/87) showed >90% PFGE profile similarity. The biofilm-forming capacity of the tested isolates, determined with crystal violet assay in polystyrene microwell plates, was generally weak. The average biofilm formation for persistent strains was higher than for presumably nonpersistent strains; however, the difference was not significant. It seems that S. Infantis persistence on broiler farms is more related to its widespread occurrence in the broiler production chain and ineffective disinfection protocols than to its ability to form biofilm.}, } @article {pmid30881614, year = {2019}, author = {Patil, PC and Tan, J and Demuth, DR and Luzzio, FA}, title = {'Second-generation' 1,2,3-triazole-based inhibitors of Porphyromonas gingivalis adherence to oral streptococci and biofilm formation.}, journal = {MedChemComm}, volume = {10}, number = {2}, pages = {268-279}, pmid = {30881614}, issn = {2040-2511}, support = {R01 DE023206/DE/NIDCR NIH HHS/United States ; }, abstract = {Several 'second-generation' click inhibitors of the multi-species biofilm propagated by the adherence of the oral pathogen Porphyromonas gingivalis to Streptococcus gordonii were synthesized and evaluated. The design of the structures was based on the results obtained with the first-generation diphenyloxazole 'click' inhibitors which bear suitable hydrophobic and polar groups within a dual scaffold molecule bearing a 1,2,3-triazole spacer. The structures of the synthetic targets reported herein now consist of a triazolyl(phenylsulfonylmethyl) and a triazolyl(phenylsulfinylmethyl) spacer which joins a 4,5-diphenyloxazole with both phenyl rings bearing lipophilic substituents. The triazolyl "linker" group is formed by a click reaction between the 4-azido(phenylsulfonyl/sulfinylmethyl) oxazoles and acetylenic components having aryl groups bearing hydrophobic substituents. The 1,3,5-trisubstituted-2,4,6-triazine scaffold of the most active click compounds were modeled after the structural motif termed the VXXLL nuclear receptor (NR) box. When substituted at the 3- and 5-positions with 2- and 4-fluorophenylamino and N,N-diethylamino units, the candidates bearing the 1,3,5-trisubstituted-2,4,6-triazine scaffold formed a substantial subset of the second-generation click candidates. Four of the click products, compounds 95, 111, 115 and 122 showed inhibition of the adherence of P. gingivalis to S. gordonii with an IC50 range of 2.3-4.3 μM and only 111 exhibited cytotoxic activity against telomerase immortalized gingival keratinocytes at 60 μM. These results suggest that compounds 95, 115, 122, and possibly 111 represent the most suitable compounds to evaluate for activity in vivo.}, } @article {pmid30881456, year = {2019}, author = {Awoke, N and Kassa, T and Teshager, L}, title = {Magnitude of Biofilm Formation and Antimicrobial Resistance Pattern of Bacteria Isolated from Urinary Catheterized Inpatients of Jimma University Medical Center, Southwest Ethiopia.}, journal = {International journal of microbiology}, volume = {2019}, number = {}, pages = {5729568}, pmid = {30881456}, issn = {1687-918X}, abstract = {Biofilm formation is one of the features of most bacteria. Catheterization in medicine is a source of highly resistant bacterial infections, and those bacteria respond poorly to antimicrobial therapy. Bacterial biofilm features were not described from catheterized inpatients in Ethiopia as its formation is known to afford antimicrobial resistance and challenge patient management. The aim of this study was to isolate catheter-associated urinary bacterial pathogens, their biofilm formation, and antimicrobial susceptibility pattern among inpatients of Jimma University Medical Center (JUMC) in Southwest Ethiopia. A prospective cross-sectional study was conducted among urinary catheterized inpatients of JUMC from February to August 2016. A total of 143 study participants were enrolled consecutively in this study. Urine samples were collected from catheterized patients and processed using a standard bacteriological protocol for isolation and identification. Evaluation of in vitro biofilm formation and antimicrobial susceptibility pattern of uropathogenic bacteria was done using microtiter plates and disk diffusion method, respectively. Data were cleaned, coded, and entered into SPSS version 20 for analysis. All statistical test values of p < 0.05 were considered statistically significant. From all study participants, mean age was 44 years. Sixty bacterial strains were recovered from 57 urinary catheterized inpatients among which 54 of them were monomicrobial (94.7%). The remaining six bacterial strains were recovered from three study participants each with two bacterial isolates. The predominant bacterial isolates were Gram-negative bacteria with E. coli turning out first. About 80% of bacterial isolates were biofilm formers. The majority of the bacteria were resistant to commonly prescribed antimicrobial agents. In conclusion, the majority of bacterial uropathogen isolates were Gram-negative, biofilm formers, and resistant to commonly prescribed antimicrobial agents. Relatively ciprofloxacin, nitrofurantoin, and amikacin were highly effective against most isolated bacteria.}, } @article {pmid30880981, year = {2019}, author = {Fu, YY and Zhang, L and Yang, Y and Liu, CW and He, YN and Li, P and Yu, X}, title = {Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing Acinetobacter baumannii.}, journal = {International journal of nanomedicine}, volume = {14}, number = {}, pages = {1805-1815}, pmid = {30880981}, issn = {1178-2013}, mesh = {Acinetobacter baumannii/*drug effects/*physiology/ultrastructure ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chitosan/*chemistry ; Drug Liberation ; Drug Synergism ; Humans ; Liposomes ; Microbial Sensitivity Tests ; *Microbubbles ; Polymyxin B/*pharmacology ; *Ultrasonics ; }, abstract = {PURPOSE: Resistant strains of Acinetobacter baumannii (AB) that can form biofilms are resistant to polymyxin. Therefore, effective and safe polymyxin preparations against biofilm-producing AB are urgently needed. This study aims to prepare chitosan-modified polymyxin B-loaded liposomes (CLPs) and ultrasound microbubbles (USMBs) and then explore the synergistic antibacterial effects of USMBs combined with CLPs in vitro.

METHODS: CLPs were prepared using a modified injection method, and microbubbles were prepared using a simple mechanical vibration method. Minimal biofilm inhibitory concentration (MBIC) of CLPs against resistant biofilm-producing AB was determined. Antibacterial activities of CLPs with or without USMBs were analyzed by crystal violet staining and resazurin assays to evaluate biofilm mass and viable counts, respectively. Then, the anti-biofilm effects of CLPs with or without USMBs on biofilm-producing AB were confirmed via scanning electron microscopy (SEM) analysis.

RESULTS: We prepared CLPs that were 225.17±17.85 nm in size and carried positive charges of 12.64±1.44 mV. These CLPs, with higher encapsulation efficiency and drug loading, could exhibit a sustained release effect. We prepared microbubbles that were 2.391±0.052 µm in size and carried negative charges of -4.32±0.43 mV. The MBICs of the CLPs on the biofilm-producing AB was 8±2 µg/mL, while that of polymyxin B was 32±2 µg/mL. USMBs in combination with 2 µg/mL of polymyxin B could completely eliminate the biofilm-producing AB and achieve the maximum antimicrobial effects (P>0.05 vs sterile blank control). SEM imaging revealed some scattered bacteria without a biofilm structure in the USMB combined with the CLP group, confirming that this combination has the greatest anti-biofilm effects.

CONCLUSION: In this research, we successfully prepared USMBs and CLPs that have a more significant antibacterial effect on biofilm-forming AB than polymyxin B alone. Experiments in vitro indicate that the synergistic antibacterial effect of combining USMBs with CLPs containing as little as 2 µg/mL of polymyxin B is sufficient to almost eliminate drug-resistant biofilm-producing AB.}, } @article {pmid30877884, year = {2019}, author = {Roeslan, MO and Ayudhya, TDN and Yingyongnarongkul, BE and Koontongkaew, S}, title = {Anti-biofilm, nitric oxide inhibition and wound healing potential of purpurin-18 phytyl ester isolated from Clinacanthus nutans leaves.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {113}, number = {}, pages = {108724}, doi = {10.1016/j.biopha.2019.108724}, pmid = {30877884}, issn = {1950-6007}, mesh = {Acanthaceae/chemistry ; Animals ; Anti-Inflammatory Agents/administration & dosage/pharmacology ; Biofilms/*drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Esters ; Fibroblasts/drug effects/metabolism ; Gingiva/cytology ; Humans ; Lipopolysaccharides/administration & dosage ; Mice ; Nitric Oxide/*antagonists & inhibitors ; Plant Extracts/pharmacology ; Plant Leaves ; Porphyrins/chemistry/isolation & purification/*pharmacology ; RAW 264.7 Cells ; Streptococcus mutans/drug effects ; Wound Healing/*drug effects ; }, abstract = {AIMS: Clinacanthus nutans (C. nutans) has demonstrated anti-inflammatory activity, however, the active compound generating this activity remains unknown. The aim of this study was to identify the bioactive compound in C. nutans responsible for its anti-inflammatory, in-vitro wound healing, and anti-biofilm activities.

MAIN METHODS: A pure compound was isolated from the chloroform extract (CE) of C. nutans leaves by chromatographic techniques and bioassay-guided fractionation. This compound's structure was determined by spectroscopic analyses (FTIR/NMR/HRES-MS). Biological activities were evaluated using cytotoxicity, nitric oxide (NO), wound scratch, anti-microbial activity, and anti-biofilm assays; and the compound's bactericidal depth into the biofilm was visualized by confocal laser scanning microscopy.

KEY FINDINGS: CE and its pure isolated compound, purpurin-18 phytyl ester (P18PE), significantly inhibited lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells at concentrations of 100 μg/ml and 10-100 μg/ml, respectively. These concentrations significantly induced wound closure by human gingival fibroblasts. CE (100-1000μg/ml) and P18PE (1-500 μg/ml) did not inhibit Streptococcus (S.) mutans growth. However, these concentrations significantly reduced S. mutans biofilm formation below 50% at 250 μg/ml for CE, and 25 μg/ml for P18PE (p<0.05).

SIGNIFICANCE: C. nutans contains a bioactive compound, P18PE, which exhibits anti-inflammatory, in-vitro wound healing, and anti-biofilm activities.}, } @article {pmid30876404, year = {2019}, author = {Khider, M and Hjerde, E and Hansen, H and Willassen, NP}, title = {Differential expression profiling of ΔlitR and ΔrpoQ mutants reveals insight into QS regulation of motility, adhesion and biofilm formation in Aliivibrio salmonicida.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {220}, pmid = {30876404}, issn = {1471-2164}, support = {IN-1096130//UiT-Publiseringsfondet/ ; }, mesh = {Aliivibrio salmonicida/genetics/*physiology ; *Bacterial Adhesion ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; *Cell Movement ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; *Mutation ; Operon ; *Quorum Sensing ; }, abstract = {BACKGROUND: The coordination of group behaviors in bacteria is achieved by a cell-cell signaling process called quorum sensing (QS). QS is an intercellular communication system, which synchronously controls expression of a vast range of genes in response to changes in cell density and is mediated by autoinducers that act as extracellular signals. Aliivibrio salmonicida, the causative agent of cold-water vibrosis in marine aquacultures, uses QS to regulate several activities such as motility, biofilm formation, adhesion and rugose colony morphology. However, little is known about either genes or detailed mechanisms involved in the regulation of these phenotypes.

RESULTS: Differential expression profiling allowed us to define the genes involved in controlling phenotypes related to QS in A. salmonicida LFI1238. RNA sequencing data revealed that the number of expressed genes in A. salmonicida, ΔlitR and ΔrpoQ mutants were significantly altered due to changes in cell density. These included genes that were distributed among the 21 functional groups, mainly presented in cell envelope, cell processes, extrachromosomal/foreign DNA and transport-binding proteins functional groups. The comparative transcriptome of A. salmonicida wild-type at high cell density relative to low cell density revealed 1013 genes to be either up- or downregulated. Thirty-six downregulated genes were gene clusters encoding biosynthesis of the flagellar and chemotaxis genes. Additionally we identified significant expression for genes involved in acyl homoserine lactone (AHL) synthesis, adhesion and early colonization. The transcriptome profile of ΔrpoQ compared to the wild-type revealed 384 differensially expressed genes (DEGs) that allowed us to assign genes involved in regulating motility, adhesion and colony rugosity. Indicating the importance of RpoQ in controlling several QS related activities. Furthermore, the comparison of the transcriptome profiles of ΔlitR and ΔrpoQ mutants, exposed numerous overlapping DEGs that were essential for motility, exopolysaccharide production via syp operon and genes associated with tad operon.

CONCLUSION: Our findings indicate previously unexplained functional roles for LitR and RpoQ in regulation of different phenotypes related to QS. Our transcriptome data provide a better understanding of the regulation cascade of motility, wrinkling colony morphology and biofilm formation and will offer a major source for further research and analysis on this important field.}, } @article {pmid30874983, year = {2019}, author = {Liu, N and Skauge, T and Landa-Marbán, D and Hovland, B and Thorbjørnsen, B and Radu, FA and Vik, BF and Baumann, T and Bødtker, G}, title = {Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in the flowing and no-flowing microchannels.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {46}, number = {6}, pages = {855-868}, pmid = {30874983}, issn = {1476-5535}, support = {255426//Research Council of Norway/ ; }, mesh = {Bacterial Adhesion/physiology ; Bacteriological Techniques/*methods ; Biofilms/drug effects/*growth & development ; Hydrodynamics ; Microfluidics/instrumentation/*methods ; Microscopy, Confocal ; Nutrients/*pharmacology ; Real-Time Polymerase Chain Reaction ; Stress, Mechanical ; Water Movements ; Water Purification ; }, abstract = {Biofilm accumulation in porous media can cause pore plugging and change many of the physical properties of porous media. Engineering bioplugging may have significant applications for many industrial processes, while improved knowledge on biofilm accumulation in porous media at porescale in general has broad relevance for a range of industries as well as environmental and water research. The experimental results by means of microscopic imaging over a T-shape microchannel clearly show that increase in fluid velocity could facilitate biofilm growth, but that above a velocity threshold, biofilm detachment and inhibition of biofilm formation due to high shear stress were observed. High nutrient concentration prompts the biofilm growth; however, the generated biofilm displays a weak adhesive strength. This paper provides an overview of biofilm development in a hydrodynamic environment for better prediction and modelling of bioplugging processes associated with porous systems in petroleum industry, hydrogeology and water purification.}, } @article {pmid30874395, year = {2019}, author = {Yang, J and Qiu, L and Huang, Y and Chen, Y and Rao, S and Ruan, W and Zhao, G and Ye, L}, title = {[The inhibition of accessory gene regulator C specific binding peptides on biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride in vitro].}, journal = {Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery}, volume = {33}, number = {3}, pages = {349-355}, pmid = {30874395}, issn = {1002-1892}, mesh = {*Biofilms ; Genes, Bacterial ; Genes, Regulator ; Microscopy, Electron, Scanning ; *Peptides/pharmacology ; *Polyvinyl Chloride ; *Staphylococcus epidermidis/growth & development ; }, abstract = {OBJECTIVE: To investigate the effect of accessory gene regulator C (agr C) specific binding peptides (named N1) on the biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride (PVC) materials in vitro.

METHODS: Firstly, the two strains (ATCC35984, ATCC12228) were cultured with N1 at concentrations of 100, 200, 400, 800, and 1 600 μg/mL, respectively. The control group was cultured with agrC specific binding unrelated peptides (named N0) at the same concentrations and the absorbance (A) value was measured after 24 hours to determine the optimal bacteriostatic concentration of N1. The two strains were cultured with N1 and N0 of the optimal concentration, respectively. The A values were measured at 6, 12, 18, 24, 30, and 48 hours to observe the effect of N1 on the biofilm formation ability of Staphylococcus epidermidis. On this basis, the surface structure of the biofilm on the surface of PVC material was observed by scanning electron microscopy after 6, 12, 18, 24, and 30 hours of incubation with PVC material sheet. The thickness of the biofilm was observed by laser confocal microscopy after 6, 12, 18, and 24 hours of incubation with ATCC35984 strain.

RESULTS: The optimal bacteriostatic concentration of N1 was 800 μg/mL. ATCC 12228 strain did not form obvious biofilm after being cultured with N1 and N0. When ATCC35984 strain was cultured with N1 and N0 for 12 hours, the difference in biofilm formation ability between groups N1 and N0 was statistically significant (P<0.05), but there was no significant difference at 6, 18, 24, 30, and 48 hours (P>0.05). Scanning electron microscopy examination showed that mature biofilm structure was observed in ATCC35984 strain and was not observed in ATCC12228 strain. Laser confocal microscopy observation showed that the number of bacteria in the group N1 was significantly lower than that in the group N0 at 12 hours, and the most of bacteria were dead bacteria. There was no significant difference in the number of bacteria at 6, 18, and 24 hours, and the most of them were live bacteria. The biofilm thickness of group N1 was significantly lower than that of group N0 at 12 and 18 hours (P<0.05).

CONCLUSION: The intensity of N1 inhibiting the formation of Staphylococcus epidermidis biofilm is dose-dependent. During the aggregation period, N1 can inhibit the biofilm formation by hindering the bacterial growth and aggregation. The inhibition effect on mature biofilm is not obvious.}, } @article {pmid30873665, year = {2019}, author = {Lerch, MF and Schoenfelder, SMK and Marincola, G and Wencker, FDR and Eckart, M and Förstner, KU and Sharma, CM and Thormann, KM and Kucklick, M and Engelmann, S and Ziebuhr, W}, title = {A non-coding RNA from the intercellular adhesion (ica) locus of Staphylococcus epidermidis controls polysaccharide intercellular adhesion (PIA)-mediated biofilm formation.}, journal = {Molecular microbiology}, volume = {111}, number = {6}, pages = {1571-1591}, doi = {10.1111/mmi.14238}, pmid = {30873665}, issn = {1365-2958}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Operon ; Polysaccharides, Bacterial/*physiology ; Promoter Regions, Genetic ; RNA, Untranslated/*genetics ; Staphylococcus epidermidis/*genetics/growth & development ; Transcription, Genetic ; }, abstract = {Polysaccharide intercellular adhesin (PIA)-associated biofilm formation is mediated by the intercellular adhesin (ica) locus and represents a major pathomechanism of Staphylococcus epidermidis. Here, we report on a novel long non-coding (nc)RNA, named IcaZ, which is approximately 400 nucleotides in size. icaZ is located downstream of the ica repressor gene icaR and partially overlaps with the icaR 3' UTR. icaZ exclusively exists in ica-positive S. epidermidis, but not in S. aureus or other staphylococci. Inactivation of the gene completely abolishes PIA production. IcaZ is transcribed as a primary transcript from its own promoter during early- and mid-exponential growth and its transcription is induced by low temperature, ethanol and salt stress. IcaZ targets the icaR 5' UTR and hampers icaR mRNA translation, which alleviates repression of icaADBC operon transcription and results in PIA production. Interestingly, other than in S. aureus, posttranscriptional control of icaR mRNA in S. epidermidis does not involve icaR mRNA 5'/3' UTR base pairing. This suggests major structural and functional differences in icaADBC operon regulation between the two species that also involve the recruitment of ncRNAs. Together, the IcaZ ncRNA represents an unprecedented novel species-specific player involved in the control of PIA production in NBSP S. epidermidis.}, } @article {pmid30873271, year = {2018}, author = {Hosseini, SS and Ghaemi, E and Koohsar, F}, title = {Influence of ZnO nanoparticles on Candida albicans isolates biofilm formed on the urinary catheter.}, journal = {Iranian journal of microbiology}, volume = {10}, number = {6}, pages = {424-432}, pmid = {30873271}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The aim of this study was to determine the effect of zinc oxide nanoparticle (ZnO-np) solution in the surface catheter on C. albicans adhesion and biofilm formation.

MATERIALS AND METHODS: Out of 260 isolates from urinary catheter, 133 were determined as C. albicans by common phenotypic and genotyping methods. ZnO nanoparticles with 30 nm were made by the sol-gel method, which was confirmed by XRD (X-ray diffraction) and scanning electron microscope (SEM) methods. Candidal adhesion and biofilm assays were performed on catheter surfaces for 2 and 48 hours, respectively. The effect of sub-MIC (minimum inhibitory concentrations) and MIC concentrations of ZnO-np on biofilm formation was evaluated after 24 hours using Crystal violet (CV), colony-forming unit (CFU), and SEM.

RESULTS: Out of 133 C. albicans isolates, 20 (15%) fluconazole-resistant and 113 (85%) susceptible isolates were determined by the disk diffusion method. Results showed that both isolates adhered to biofilm formation on the catheter surfaces. A significantly (P< 0.05) higher number of CFUs was evident in fluconazole-resistant biofilms compared to those formed by susceptible isolates. ZnO-np reduced biofilm biomass and CFUs of dual isolate biofilms (P< 0.05). ZnO nanoparticles had a significantly (P< 0.05) greater effect on reducing fluconazole-resistant C. albicans biofilm biomass compared to susceptible isolates.

CONCLUSION: Zno-np exhibits inhibitory effects on biofilms of both isolates. These findings provide an important advantage of ZnO that may be useful in the treatment of catheter-related urinary tract infection.}, } @article {pmid30873270, year = {2018}, author = {Baghini, GS and Sepahi, AA and Tabatabaei, RR and Tahvildari, K}, title = {The combined effects of ethanolic extract of Artemisia aucheri and Artemisia oliveriana on biofilm genes expression of methicillin resistant Staphylococcus aureus.}, journal = {Iranian journal of microbiology}, volume = {10}, number = {6}, pages = {417-423}, pmid = {30873270}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: One of the most important antibiotic-resistant bacteria is methicillin-resistant Staphylococcus aureus (MRSA) biofilm that has caused significant problems in treating the patients. Therefore, the aim of this study was to evaluate the levels of expression of genes involved in biofilm formation in MRSA (ATCC 33591) while being treated by a combination of Artemisia aucheri and Artemisia oliveriana.

MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of ethanolic extract of A. aucheri and A. oliveriana and also the minimum inhibitory concentration of combination of both extracts were 512, 1024 and 256 μg/ml, respectively; then at concentrations lower than the MIC, expression levels of the desired genes were determined by Real Time PCR.

RESULTS: Based on results, using a combination of two ethanolic extracts had a significant effect on expression of genes involved in biofilm formation in MRSA. The expression level of icaA at 4, 8, 16 h after being treated by herbal extracts of A. aucheri and A. oliveriana was 0.293, 0.121, 0.044, respectively. The expression level of icaD was 0.285, 0.097, 0.088, respectively, while that of ebps was 0.087, 0.042, 0.009 at 4, 8 and 16 h, respectively.

CONCLUSION: This study provided evidence that ethanol extract of A. oliveriava and A. aucheri can inhibit the biofilm formation of S. aureus. As a traditional Iranian medicine, A. oliveriava and A. aucheri extracts have a potential antibiofilm formation against MRSA strains.}, } @article {pmid30873149, year = {2019}, author = {Calderón, CE and Tienda, S and Heredia-Ponce, Z and Arrebola, E and Cárcamo-Oyarce, G and Eberl, L and Cazorla, FM}, title = {The Compound 2-Hexyl, 5-Propyl Resorcinol Has a Key Role in Biofilm Formation by the Biocontrol Rhizobacterium Pseudomonas chlororaphis PCL1606.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {396}, pmid = {30873149}, issn = {1664-302X}, abstract = {The production of the compound 2-hexyl-5-propyl resorcinol (HPR) by the biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 (PcPCL1606) is crucial for fungal antagonism and biocontrol activity that protects plants against the phytopathogenic fungus Rosellinia necatrix. The production of HPR is also involved in avocado root colonization during the biocontrol process. This pleiotrophic response prompted us to study the potential role of HPR production in biofilm formation. The swimming motility of PcPLL1606 is enhanced by the disruption of HPR production. Mutants impaired in HPR production, revealed that adhesion, colony morphology, and typical air-liquid interphase pellicles were all dependent on HPR production. The role of HPR production in biofilm architecture was also analyzed in flow chamber experiments. These experiments revealed that the HPR mutant cells had less tight unions than those producing HPR, suggesting an involvement of HPR in the production of the biofilm matrix.}, } @article {pmid30872708, year = {2019}, author = {Ansari, FA and Ahmad, I}, title = {Fluorescent Pseudomonas -FAP2 and Bacillus licheniformis interact positively in biofilm mode enhancing plant growth and photosynthetic attributes.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {4547}, pmid = {30872708}, issn = {2045-2322}, mesh = {Bacillus licheniformis/*physiology ; Biofilms/*growth & development ; Chlorophyll/metabolism ; *Photosynthesis ; *Plant Development ; Plant Leaves/growth & development/microbiology ; Plant Roots/*growth & development/microbiology ; Pseudomonas/*physiology ; Rhizosphere ; Siderophores ; Soil Microbiology ; Triticum/*growth & development/microbiology ; }, abstract = {Compatible interaction between commonly used plant growth promoting rhizobacteria (PGPR) in biofilm mode in vitro and in the rhizosphere is expected to provide better understanding for the development of effective consortium. With the above hypothesis, the present study evaluated two characterized PGPR (Pseudomonas fluorescens FAP2 and Bacillus licheniformis B642) for their biofilm-related functions using standard protocols. The interaction between the FAP2 and B642 in planktonic mode was studied by plate spot/overlay method and competitive growth assessment. Biofilm development on a microtitre plate and a glass surface was studied by standard methods. Biofilm formation was characterized by SEM. Rhizosphere and rhizoplane colonization of wheat seedlings by both isolates individually and by co-inoculation was studied by determining CFU/g of soil/root samples. Biofilm development on the root surface was further analyzed by SEM. Both isolates demonstrated multiple plant growth promoting (PGP) traits (production of IAA, siderophore, and ammonia; phosphate solubilization) and biofilm-related functions such as production of EPS, alginate, cell surface hydrophobicity and swarming motility. Both strains formed strong biofilms on a glass cover slip in vitro. Interaction between the two strains under the planktonic mode revealed no antagonism in terms of growth inhibition and competitive growth kinetics. Similarly, FAP2 and B642 strains formed a mixed biofilm on a glass cover slip as well as on seedling roots. Wheat rhizosphere and rhizoplane were colonized by both isolates as evidenced from their viable counts in single and co-inoculation. The effect of single and co inoculation revealed the significant enhancement of vegetative growth and photosynthetic parameters such as chlorophyll content, transpiration rate (E), internal CO2 concentration (Ci), stomatal conductance (gs), and net photosynthetic rate (PN) and leaf water potential (LWP) as compared to uninoculated control. Indigenous Pseudomonas fluorescens FAP2 strain and Bacillus licheniformis B642 are compatible PGPR in both planktonic and biofilm modes of growth and threfore could be developed effective consortium of PGPR. Further indepth investigation is required to understand molecular mechanism of the interaction in biofilm mode of growth under natural condition.}, } @article {pmid30872074, year = {2019}, author = {Siddique, A and Suraraksa, B and Horprathum, M and Oaew, S and Cheunkar, S}, title = {Wastewater biofilm formation on self-assembled monolayer surfaces using elastomeric flow cells.}, journal = {Anaerobe}, volume = {57}, number = {}, pages = {11-18}, doi = {10.1016/j.anaerobe.2019.03.005}, pmid = {30872074}, issn = {1095-8274}, mesh = {Anaerobiosis ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Cell Adhesion ; Surface Properties ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {In anaerobic wastewater treatment, microbial biofilm is beneficial for efficient substrate utilization and for preventing the wash-out of key microorganisms. By providing solid supports, biofilm formation can be accelerated due to the early initial adhesion of residing microbes. Alteration in surface properties is therefore one such approach that helps us understand microbial interfacial interaction. Here, self-assembled monolayers of alkanethiols with carboxyl (-COOH), hydroxyl (-OH), and amine (-NH2) terminal moieties on gold (Au) substrates were employed to study the initial adhesion of wastewater microbes. An elastomeric flow cell was also utilized to simulate the environment of wastewater bioreactor. Results from fluorescence in situ hybridization (FISH) portrayed more enhanced microbial adhesion after 2 h on -NH2 functional group with the calculated surface coverage of 12.8 ± 2.4% as compared to 7.7 ± 1.6% on -COOH, 11.0 ± 2.0% on -OH, and 1.2% on unmodified Au surfaces. This might be because of concomitant electrostatic attraction between negatively-charged bacteria and positively-charged (-NH3[+]) functional groups. Nevertheless, the average surface coverage by individual biofilm clusters was 28.0 ± 5.0 μm[2] and 32.0 ± 9.0 μm[2] on -NH2 and -OH surfaces, respectively, while -COOH surfaces resulted in higher value (60.0 ± 5.0 μm[2]) and no significant cluster formation was observed on Au surfaces. Accordingly, the average inter-cluster distance observed on -NH2 surfaces was relatively smaller (3.0 ± 0.6 μm) as compared to that on other surfaces. Overall, these data suggest favorable initial biofilm growth on more hydrophilic and positively-charged surfaces. Furthermore, the analysis of the mean fluorescence intensity revealed preferred initial adhesion of key microbes (archaea) on -OH and -NH2 surfaces. Indeed, results obtained from this study would be beneficial in designing selective biointerfaces for certain biofilm carriers in a typical wastewater bioreactor. Importantly, our elastomeric flow cell integrated with SAM-modified surfaces demonstrated an ideal platform for high-throughput investigation of wastewater biofilm under controlled environments.}, } @article {pmid30871787, year = {2019}, author = {Modiri, M and Khodavaisy, S and Barac, A and Akbari Dana, M and Nazemi, L and Aala, F and Salehi, M and Rezaie, S}, title = {Comparison of biofilm-producing ability of clinical isolates of Candida parapsilosis species complex.}, journal = {Journal de mycologie medicale}, volume = {29}, number = {2}, pages = {140-146}, doi = {10.1016/j.mycmed.2019.02.003}, pmid = {30871787}, issn = {1773-0449}, mesh = {Biofilms/*growth & development ; Biomass ; Candida parapsilosis/*physiology/ultrastructure ; Candidiasis/microbiology ; Gentian Violet ; Humans ; Invasive Fungal Infections/microbiology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Retrospective Studies ; }, abstract = {OBJECTIVE: Candida parapsilosis is one of the main emerging non-Candida albicans species leading to superficial and systemic fungal infections in humans. Candida has the ability to produce biofilms associated with pathogenesis. The aim of the study was to estimate biofilm-producing ability of clinical isolates of C. parapsilosis sp. complex.

METHODS: Clinical samples of C. parapsilosis complex have been analyzed. Crystal violet (CV) staining and tetrazolium reduction assay (MTT) have been used to analyze the clinical isolates ability to produce biofilms. The biofilm's structural characteristics have been assessed by using scanning electron microscopy.

RESULTS: All 65 isolates were able to form biofilm. In addition, no significant difference was found between biofilm quantification based on two assays at different time intervals (24h, 48h, 72h, 96h) (P>0.05), with the exception of Candida orthopsilosis, which exhibited higher metabolic activity at 24h time point (P<0.05). Moreover, metabolic activity and production of biofilm biomass demonstrated statistically significant correlation (r=0.685, P<0.01). According to microscopic observations, the investigated clinical strains formed the similar surface topography with the slight differences in morphology; in addition, there was no statistically significant difference between efficiency of two assays to quantify biofilm.

CONCLUSION: It was shown that, similar to C. parapsilosissensu stricto, two cryptic identified species (C. orthopsilosis and Candida metapsilosis) obtained from different clinical samples, were biofilm producers, while C. parapsilosissensu stricto exhibited the highest biofilm production.}, } @article {pmid30870985, year = {2019}, author = {Henry, M and Fouladkhah, A}, title = {Outbreak History, Biofilm Formation, and Preventive Measures for Control of Cronobacter sakazakii in Infant Formula and Infant Care Settings.}, journal = {Microorganisms}, volume = {7}, number = {3}, pages = {}, pmid = {30870985}, issn = {2076-2607}, abstract = {Previously known as Enterobacter sakazakii from 1980 to 2007, Cronobacter sakazakii is an opportunistic bacterium that survives and persists in dry and low-moisture environments, such as powdered infant formula. Although C. sakazakii causes disease in all age groups, infections caused by this pathogen are particularly fatal in infants born premature and those younger than two months. The pathogen has been isolated from various environments such as powdered infant formula manufacturing facilities, healthcare settings, and domestic environments, increasing the chance of infection through cross-contamination. The current study discusses the outbreak history of C. sakazakii and the ability of the microorganism to produce biofilms on biotic and abiotic surfaces. The study further discusses the fate of the pathogen in low-moisture environments, articulates preventive measures for healthcare providers and nursing parents, and delineates interventions that could be utilized in infant formula manufacturing to minimize the risk of contamination with Cronobacter sakazakii.}, } @article {pmid30870530, year = {2019}, author = {Schoenfelder, SMK and Lange, C and Prakash, SA and Marincola, G and Lerch, MF and Wencker, FDR and Förstner, KU and Sharma, CM and Ziebuhr, W}, title = {The small non-coding RNA RsaE influences extracellular matrix composition in Staphylococcus epidermidis biofilm communities.}, journal = {PLoS pathogens}, volume = {15}, number = {3}, pages = {e1007618}, pmid = {30870530}, issn = {1553-7374}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Extracellular Matrix/*genetics/physiology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/genetics ; Operon/genetics ; Phenotype ; Polysaccharides, Bacterial/genetics/metabolism ; RNA, Small Untranslated/genetics/*metabolism ; Staphylococcal Infections/genetics/metabolism ; Staphylococcus/genetics ; Staphylococcus epidermidis/*genetics/metabolism ; }, abstract = {RsaE is a conserved small regulatory RNA (sRNA) which was previously reported to represent a riboregulator of central carbon flow and other metabolic pathways in Staphylococcus aureus and Bacillus subtilis. Here we show that RsaE contributes to extracellular (e)DNA release and biofilm-matrix switching towards polysaccharide intercellular adhesin (PIA) production in a hypervariable Staphylococcus epidermidis isolate. Transcriptome analysis through differential RNA sequencing (dRNA-seq) in combination with confocal laser scanning microscopy (CLSM) and reporter gene fusions demonstrate that S. epidermidis protein- and PIA-biofilm matrix producers differ with respect to RsaE and metabolic gene expression. RsaE is spatiotemporally expressed within S. epidermidis PIA-mediated biofilms, and its overexpression triggers a PIA biofilm phenotype as well as eDNA release in an S. epidermidis protein biofilm matrix-producing strain background. dRNA-seq and Northern blot analyses revealed RsaE to exist as a major full-length 100-nt transcript and a minor processed species lacking approximately 20 nucleotides at the 5'-end. RsaE processing results in expansion of the mRNA target spectrum. Thus, full-length RsaE interacts with S. epidermidis antiholin-encoding lrgA mRNA, facilitating bacterial lysis and eDNA release. Processed RsaE, however, interacts with the 5'-UTR of icaR and sucCD mRNAs, encoding the icaADBC biofilm operon repressor IcaR and succinyl-CoA synthetase of the tricarboxylic acid (TCA) cycle, respectively. RsaE augments PIA-mediated biofilm matrix production, most likely through activation of icaADBC operon expression via repression of icaR as well as by TCA cycle inhibition and re-programming of staphylococcal central carbon metabolism towards PIA precursor synthesis. Additionally, RsaE supports biofilm formation by mediating the release of eDNA as stabilizing biofilm matrix component. As RsaE itself is heterogeneously expressed within biofilms, we consider this sRNA to function as a factor favoring phenotypic heterogeneity and supporting division of labor in S. epidermidis biofilm communities.}, } @article {pmid30870411, year = {2019}, author = {Williams, DL and Smith, SR and Peterson, BR and Allyn, G and Cadenas, L and Epperson, RT and Looper, RE}, title = {Growth substrate may influence biofilm susceptibility to antibiotics.}, journal = {PloS one}, volume = {14}, number = {3}, pages = {e0206774}, pmid = {30870411}, issn = {1932-6203}, support = {I01 RX001198/RX/RRD VA/United States ; I01 RX002287/RX/RRD VA/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/drug effects/*growth & development ; Biofilms/drug effects/*growth & development ; Bioreactors/*microbiology ; Collagen/chemistry/*metabolism ; Polycarboxylate Cement/chemistry/*metabolism ; }, abstract = {The CDC biofilm reactor is a robust culture system with high reproducibility in which biofilms can be grown for a wide variety of analyses. Multiple material types are available as growth substrates, yet data from biofilms grown on biologically relevant materials is scarce, particularly for antibiotic efficacy against differentially supported biofilms. In this study, CDC reactor holders were modified to allow growth of biofilms on collagen, a biologically relevant substrate. Susceptibility to multiple antibiotics was compared between biofilms of varying species grown on collagen versus standard polycarbonate coupons. Data indicated that in 13/18 instances, biofilms on polycarbonate were more susceptible to antibiotics than those on collagen, suggesting that when grown on a complex substrate, biofilms may be more tolerant to antibiotics. These outcomes may influence the translatability of antibiotic susceptibility profiles that have been collected for biofilms on hard plastic materials. Data may also help to advance information on antibiotic susceptibility testing of biofilms grown on biologically relevant materials for future in vitro and in vivo applications.}, } @article {pmid30869588, year = {2018}, author = {Vinson, LA and Gilbert, PR and Sanders, BJ and Moser, E and Gregory, RL}, title = {Silver Diamine Fluoride and Potassium Iodide Disruption of In Vitro Streptococcus mutans Biofilm.}, journal = {Journal of dentistry for children (Chicago, Ill.)}, volume = {85}, number = {3}, pages = {120-124}, pmid = {30869588}, issn = {1935-5068}, mesh = {Biofilms/*drug effects ; Dental Caries/microbiology/prevention & control ; Drug Combinations ; Fluorides, Topical ; Microbial Viability/drug effects ; Potassium Iodide/*antagonists & inhibitors ; Quaternary Ammonium Compounds/*antagonists & inhibitors ; Silver Compounds/*antagonists & inhibitors ; Streptococcus mutans/*drug effects ; }, abstract = {Purpose: The purpose of this study was to investigate the inhibitory in vitro effects of silver diamine fluoride (SDF) with and without a saturated solution of potassium iodide (SSKI) on established Streptococcus mutans biofilm.Methods: Fifty μl of an overnight S. mutans culture (10[6] CFU per mL) in Tryptic Soy Broth (TSB) and three ml of fresh TSB supplemented with one percent sucrose (TSBS) were incubated for 24 hours to establish an S. mutans biofilm in six-well tissue culture plates. Four treatments (SDF, SSKI, SDF plus SSKI, and untreated control) were used to disrupt the biofilm. The biofilm groups were each treated with reagent and washed; the biofilm was collected, diluted, and spiral-plated onto blood agar plates; and an automated counting machine was used to determine the bacterial colony forming units (CFU).Results: The control had significantly more CFU than the SSKI, SDF, and SDF plus SSKI groups (P<.0001). The SSKI group had significantly more CFU than the SDF and SDF plus SSKI groups (P<.0001). The SDF group had significantly fewer CFU than the SDF plus SSKI group (P=.02). The reduction from the control was more than seven-fold for SDF, four-fold for SDF plus SSKI, and two-fold for SSKI.Conclusions: SDF alone, SDF plus SSKI, and SSKI disrupted an established S. mutans biofilm. SDF alone had the greatest overall disruption.}, } @article {pmid30868761, year = {2019}, author = {Roche, ED and Woodmansey, EJ and Yang, Q and Gibson, DJ and Zhang, H and Schultz, GS}, title = {Cadexomer iodine effectively reduces bacterial biofilm in porcine wounds ex vivo and in vivo.}, journal = {International wound journal}, volume = {16}, number = {3}, pages = {674-683}, pmid = {30868761}, issn = {1742-481X}, support = {//Smith & Nephew plc/ ; }, mesh = {Animals ; Anti-Infective Agents, Local/*therapeutic use ; Biofilms/*drug effects ; Chronic Disease/drug therapy ; Humans ; Iodophors/*therapeutic use ; Models, Animal ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; Swine ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {Biofilms are prevalent in non-healing chronic wounds and implicated in delayed healing. Tolerance to antimicrobial treatments and the host's immune system leave clinicians with limited interventions against biofilm populations. It is therefore essential that effective treatments be rigorously tested and demonstrate an impact on biofilm across multiple experimental models to guide clinical investigations and protocols. Cadexomer iodine has previously been shown to be effective against biofilm in various in vitro models, against methicillin-resistant Staphylococcus aureus biofilm in mouse wounds, and clinically in diabetic foot ulcers complicated by biofilm. Similarities between porcine and human skin make the pig a favoured model for cutaneous wound studies. Two antiseptic dressings and a gauze control were assessed against mature biofilm grown on ex vivo pig skin and in a pig wound model. Significant reductions in biofilm were observed following treatment with cadexomer iodine across both biofilm models. In contrast, silver carboxymethylcellulose dressings had minimal impact on biofilm in the models, with similar results to the control in the ex vivo model. Microscopy and histopathology indicate that the depth of organisms in wound tissue may impact treatment effectiveness. Further work on the promising biofilm efficacy of cadexomer iodine is needed to determine optimal treatment durations against biofilm.}, } @article {pmid30868754, year = {2019}, author = {Parnasa, R and Sendersky, E and Simkovsky, R and Waldman Ben-Asher, H and Golden, SS and Schwarz, R}, title = {A microcin processing peptidase-like protein of the cyanobacterium Synechococcus elongatus is essential for secretion of biofilm-promoting proteins.}, journal = {Environmental microbiology reports}, volume = {11}, number = {3}, pages = {456-463}, doi = {10.1111/1758-2229.12751}, pmid = {30868754}, issn = {1758-2229}, support = {//National Science Foundation/International ; NSF-BSF 2012823//US-Israel Binational Science Foundation/International ; ISF 1406/14//Israel Science Foundation/International ; }, mesh = {Amino Acid Motifs ; Bacterial Proteins/*metabolism ; Bacteriocins/chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Extracellular Space/metabolism ; Mutation ; Peptide Hydrolases/chemistry/genetics/*metabolism ; Protein Processing, Post-Translational ; Protein Transport ; Proteome ; Synechococcus/chemistry/genetics/*metabolism/physiology ; }, abstract = {Small secreted compounds, e.g. microcins, are characterized by a double-glycine (GG) secretion motif that is cleaved off upon maturation. Genomic analysis suggests that small proteins that possess a GG motif are widespread in cyanobacteria; however, the roles of these proteins are largely unknown. Using a biofilm-proficient mutant of the cyanobacterium Synechococcus elongatus PCC 7942 in which the constitutive biofilm self-suppression mechanism is inactivated, we previously demonstrated that four small proteins, Enable biofilm formation with a GG motif (EbfG1-4), each with a GG motif, enable biofilm formation. Furthermore, a peptidase belonging to the C39 family, Peptidase transporter enabling Biofilm (PteB), is required for secretion of these proteins. Here, we show that the microcin processing peptidase-like protein encoded by gene Synpcc7942_1127 is also required for biofilm development - inactivation of this gene in the biofilm-proficient mutant abrogates biofilm development. Additionally, this peptidase-like protein (denoted EbfE - enables biofilm formation peptidase) is required for secretion of the EbfG biofilm-promoting small proteins. Given their protein-domain characteristics, we suggest that PteB and EbfE take part in a maturation-secretion system, with PteB being located to the cell membrane while EbfE is directed to the periplasmic space via its secretion signal.}, } @article {pmid30867692, year = {2019}, author = {Yu, Z and Kong, Y and Luo, Z and Liu, T and Lin, J}, title = {Anti-bacterial activity of mutant chensinin-1 peptide against multidrug-resistant Pseudomonas aeruginosa and its effects on biofilm-associated gene expression.}, journal = {Experimental and therapeutic medicine}, volume = {17}, number = {3}, pages = {2031-2038}, pmid = {30867692}, issn = {1792-0981}, abstract = {Nosocomial infections with Pseudomonas aeruginosa (PA) are difficult to treat due to the low outer membrane permeability of the bacterium and the development of resistance. In the present study, the anti-microbial peptide (AMP) mutant chensinin-1 (MC1) was revealed to exhibit anti-bacterial activity against a multidrug-resistant PA (MRPA) strain in vitro, and the minimum inhibitory concentration was 25 µM, which was 4-fold higher than that of the native strain. MC1 was able to disrupt the integrity of the cytoplasmic membrane in the native PA strain and MRPA and had a similar membrane depolarization ability in these strains, but the outer membrane permeability of MRPA cells was lower than that of native PA cells, as determined by a 1-N-phenylnaphthylamine assay. In addition, the abundance of the gene Psl encoding for biofilm-associated polysaccharides was detected using Congo red, and a high concentration of MC1 inhibited the formation of MRPA biofilms. Furthermore, the expression levels of biofilm-associated genes affected by the AMP, MC1, were quantified by polymerase chain reaction analysis. The results indicated that MC1 induced biofilm inhibition by downregulating the relative expression of specific biofilm polysaccharide-associated genes, including pelA, algD and pslA. The present results indicated that the AMP MC1 may be an effective antibiotic against MRPA strains.}, } @article {pmid30867546, year = {2019}, author = {Smith, AR and Kieft, B and Mueller, R and Fisk, MR and Mason, OU and Popa, R and Colwell, FS}, title = {Carbon fixation and energy metabolisms of a subseafloor olivine biofilm.}, journal = {The ISME journal}, volume = {13}, number = {7}, pages = {1737-1749}, pmid = {30867546}, issn = {1751-7370}, mesh = {Archaea/classification/genetics/isolation & purification/*metabolism ; Bacteria/classification/genetics/isolation & purification/*metabolism ; Biofilms ; Carbon Cycle ; Ecosystem ; Energy Metabolism ; Genome, Bacterial ; Groundwater ; Iron Compounds/*metabolism ; Magnesium Compounds/*metabolism ; Metagenome ; Nitrogen Fixation ; Oceans and Seas ; Phylogeny ; Seawater/analysis/microbiology ; Silicates/*metabolism ; }, abstract = {Earth's largest aquifer ecosystem resides in igneous oceanic crust, where chemosynthesis and water-rock reactions provide the carbon and energy that support an active deep biosphere. The Calvin Cycle is the predominant carbon fixation pathway in cool, oxic, crust; however, the energy and carbon metabolisms in the deep thermal basaltic aquifer are poorly understood. Anaerobic carbon fixation pathways such as the Wood-Ljungdahl pathway, which uses hydrogen (H2) and CO2, may be common in thermal aquifers since water-rock reactions can produce H2 in hydrothermal environments and bicarbonate is abundant in seawater. To test this, we reconstructed the metabolisms of eleven bacterial and archaeal metagenome-assembled genomes from an olivine biofilm obtained from a Juan de Fuca Ridge basaltic aquifer. We found that the dominant carbon fixation pathway was the Wood-Ljungdahl pathway, which was present in seven of the eight bacterial genomes. Anaerobic respiration appears to be driven by sulfate reduction, and one bacterial genome contained a complete nitrogen fixation pathway. This study reveals the potential pathways for carbon and energy flux in the deep anoxic thermal aquifer ecosystem, and suggests that ancient H2-based chemolithoautotrophy, which once dominated Earth's early biosphere, may thus remain one of the dominant metabolisms in the suboceanic aquifer today.}, } @article {pmid30867500, year = {2019}, author = {Bartnicka, D and Karkowska-Kuleta, J and Zawrotniak, M and Satała, D and Michalik, K and Zielinska, G and Bochenska, O and Kozik, A and Ciaston, I and Koziel, J and Dutton, LC and Nobbs, AH and Potempa, B and Baster, Z and Rajfur, Z and Potempa, J and Rapala-Kozik, M}, title = {Adhesive protein-mediated cross-talk between Candida albicans and Porphyromonas gingivalis in dual species biofilm protects the anaerobic bacterium in unfavorable oxic environment.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {4376}, pmid = {30867500}, issn = {2045-2322}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Bacteria, Anaerobic/*physiology ; Bacterial Adhesion ; *Biofilms ; Candida albicans/*physiology ; Fungal Proteins/genetics/metabolism ; Humans ; *Microbial Interactions ; Microbial Viability ; Porphyromonas gingivalis/*physiology ; Proteomics/methods ; Virulence ; }, abstract = {The oral cavity contains different types of microbial species that colonize human host via extensive cell-to-cell interactions and biofilm formation. Candida albicans-a yeast-like fungus that inhabits mucosal surfaces-is also a significant colonizer of subgingival sites in patients with chronic periodontitis. It is notable however that one of the main infectious agents that causes periodontal disease is an anaerobic bacterium-Porphyromonas gingivalis. In our study, we evaluated the different strategies of both pathogens in the mutual colonization of an artificial surface and confirmed that a protective environment existed for P. gingivalis within developed fungal biofilm formed under oxic conditions where fungal cells grow mainly in their filamentous form i.e. hyphae. A direct physical contact between fungi and P. gingivalis was initiated via a modulation of gene expression for the major fungal cell surface adhesin Als3 and the aspartic proteases Sap6 and Sap9. Proteomic identification of the fungal surfaceome suggested also an involvement of the Mp65 adhesin and a "moonlighting" protein, enolase, as partners for the interaction with P. gingivalis. Using mutant strains of these bacteria that are defective in the production of the gingipains-the proteolytic enzymes that also harbor hemagglutinin domains-significant roles of these proteins in the formation of bacteria-protecting biofilm were clearly demonstrated.}, } @article {pmid30866810, year = {2019}, author = {Sánchez, MC and Romero-Lastra, P and Ribeiro-Vidal, H and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M}, title = {Comparative gene expression analysis of planktonic Porphyromonas gingivalis ATCC 33277 in the presence of a growing biofilm versus planktonic cells.}, journal = {BMC microbiology}, volume = {19}, number = {1}, pages = {58}, pmid = {30866810}, issn = {1471-2180}, mesh = {Biofilms/*growth & development ; Gene Expression Profiling ; Genes, Bacterial ; Oligonucleotide Array Sequence Analysis ; Phenotype ; Porphyromonas gingivalis/*genetics/*physiology ; Virulence ; }, abstract = {BACKGROUND: Porphyromonas gingivalis, a microorganism residing in the oral cavity within complex multispecies biofilms, is one of the keystone pathogens in the onset and progression of periodontitis. In this in vitro study, using DNA microarray, we investigate the differential gene expression of Porphyromonas gingivalis ATCC 33277 when growing in the presence or in absence of its own monospecies biofilm.

RESULTS: Approximately 1.5% of genes (28 out of 1909 genes, at 1.5 fold change or more, p-value < 0.05) were differentially expressed by P. gingivalis cells when in the presence of a biofilm. These genes were predominantly related to the metabolism of iron, bacterial adhesion, invasion, virulence and quorum-sensing system. The results from microarrays were consistent with those obtained by RT-qPCR.

CONCLUSION: This study provides insight on the transcriptional changes of planktonic P. gingivalis cells when growing in the presence of a biofilm. The resulting phenotypes provide information on changes occurring in the gene expression of this pathogen.}, } @article {pmid30866438, year = {2019}, author = {Corte, L and Casagrande Pierantoni, D and Tascini, C and Roscini, L and Cardinali, G}, title = {Biofilm Specific Activity: A Measure to Quantify Microbial Biofilm.}, journal = {Microorganisms}, volume = {7}, number = {3}, pages = {}, pmid = {30866438}, issn = {2076-2607}, abstract = {Microbes growing onto solid surfaces form complex 3-D biofilm structures characterized by the production of extracellular polymeric compounds and an increased resistance to drugs. The quantification of biofilm relays currently on a number of different approaches and techniques, often leading to different evaluations of the ability to form biofilms of the studied microbial strains. Measures of biofilm biomass were carried out with crystal violet (CV) and a direct reading at 405 nm, whereas the activity was assessed with the XTT ((2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) method. The strains of four pathogenic species of the genus Candida (C. albicans, C. glabrata, C. parapsilosis and C. tropicalis) and of Staphylococcus aureus were employed to determine the effective relatedness among techniques and the specific activity of the biofilm, as a ratio between the XTT and the CV outcomes. Since the ability to form biomass and to be metabolically active are not highly related, their simultaneous use allowed for a categorization of the strains. This classification is putatively amenable of further study by comparing the biofilm type and the medical behavior of the strains.}, } @article {pmid30865550, year = {2019}, author = {Szell, T and Dressler, FF and Goelz, H and Bluemel, B and Miernik, A and Brandstetter, T and Scherag, F and Schoeb, DS}, title = {Response to Tailly and Van Haute: In Vitro Effects of a Novel Coating Agent on Bacterial Biofilm Development on Ureteral Stent by Schoeb et al. (From: Tailly T, Van Haute C. J Endourol 2019;33:232-233; DOI: 10.1089/end.2018.0907).}, journal = {Journal of endourology}, volume = {33}, number = {3}, pages = {234}, doi = {10.1089/end.2019.29052.tsz}, pmid = {30865550}, issn = {1557-900X}, mesh = {Biofilms ; Stents ; *Ureter ; }, } @article {pmid30865048, year = {2019}, author = {Córdoba, A and Graue-Hernandez, EO and Bermudez-Magner, JA and Ramirez-Miranda, A and Irusteta, L and Bautista-de Lucio, VM and Ponce-Angulo, DG and Bautista-Hernandez, LA and Navas, A}, title = {Corneal Biofilm Plaques: A Novel Clinical Presentation.}, journal = {Cornea}, volume = {38}, number = {6}, pages = {764-767}, doi = {10.1097/ICO.0000000000001923}, pmid = {30865048}, issn = {1536-4798}, mesh = {*Biofilms ; Child ; Corneal Diseases/*microbiology ; Eye Infections, Bacterial/*microbiology ; Eye Injuries/complications ; Gram-Negative Bacteria/*isolation & purification ; Humans ; Male ; }, abstract = {PURPOSE: To report a novel clinical presentation of corneal biofilms, consisting of formation of superficial and recurrent corneal plaques.

METHODS: Interventional case report. A 9-year-old boy presented with subepithelial, whitish, avascular, and recurrent corneal plaques without any clinical manifestations of active corneal inflammation and/or infection. He had a history of minor ocular trauma; otherwise, his medical history was unremarkable.

RESULTS: An excisional biopsy was performed under topical anesthesia. Histological analysis identified these plaques as clusters of gram-negative bacilli surrounded by an extracellular matrix. Samples were further evaluated with special stains (calcofluor white, Flamingo fluorescent dye, propidium iodide, and Gomori-Grocott) that demonstrated biofilm structures.

CONCLUSIONS: Corneal plaques are a very rare clinical presentation of corneal biofilms that allow prolonged survival of microorganisms even in the absence of prosthetic material and clinical signs or symptoms of corneal active inflammation and/or infection.}, } @article {pmid30864645, year = {2019}, author = {Rezende, G and Arthur, RA and Lamers, ML and Hashizume, LN}, title = {Structural Organization of Dental Biofilm Formed in situ in the Presence of Sucrose Associated to Maltodextrin.}, journal = {Brazilian dental journal}, volume = {30}, number = {1}, pages = {36-42}, doi = {10.1590/0103-6440201902183}, pmid = {30864645}, issn = {1806-4760}, mesh = {Adult ; *Biofilms ; Cross-Over Studies ; Double-Blind Method ; Humans ; Microscopy, Confocal ; Orthodontic Appliances ; Polysaccharides/*metabolism ; Sucrose/*metabolism ; Young Adult ; }, abstract = {Maltodextrins, derived from corn starch, have been added to industrialized food combined with sucrose. However it is not clear the diffusion properties of the dental biofilm matrix and the tridimensional structure of multispecies biofilms formed in the presence of these carbohydrates. Therefore, the aim of study was to investigate by confocal laser scanning microscopy (CLSM) the structural organization of the multispecies dental biofilm formed in situ under exposure to sucrose associated to maltodextrin. Adult volunteers wore an intraoral palatal appliance containing bovine enamel blocks. They were instructed to remove the appliance 8 times per day and drop the following solutions on the enamel blocks: deionized distilled water (DDW), maltodextrin, sucrose + maltodextrin or sucrose. Biofilms formed were stained and the percentage of extracellular polysaccharide (%EPS) and thickness were determined by CLSM. Biofilm formed in the presence of sucrose and sucrose + maltodextrin presented similar %EPS and higher than DDW and maltodextrin. Regarding to the biofilm thickness, sucrose and sucrose + maltodextrin treatments were thicker than DDW and maltodextrin and similar between them. The structural organization of the multispecies dental biofilm formed in situ in the presence of sucrose does not change when this carbohydrate is associated to maltodextrin.}, } @article {pmid30863390, year = {2019}, author = {Peel, TN}, title = {Studying Biofilm and Clinical Issues in Orthopedics.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {359}, pmid = {30863390}, issn = {1664-302X}, abstract = {The association between biofilm-forming microorganisms and prosthetic joint infection influences all aspect of management including approaches to diagnosis, management and prevention. This article will provide an overview of new anti-biofilm strategies for management of prosthetic joint infection.}, } @article {pmid30862561, year = {2019}, author = {Lopes, LQS and de Almeida Vaucher, R and Giongo, JL and Gündel, A and Santos, RCV}, title = {Characterisation and anti-biofilm activity of glycerol monolaurate nanocapsules against Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {130}, number = {}, pages = {178-185}, doi = {10.1016/j.micpath.2019.03.007}, pmid = {30862561}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Carriers ; Laurates/*pharmacology ; Microbial Sensitivity Tests ; Monoglycerides/*pharmacology ; *Nanocapsules ; Pseudomonas aeruginosa/*drug effects ; Surface-Active Agents/*pharmacology ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous microorganism that commonly causes hospital-acquired infections, including pneumonia, bloodstream and urinary tract infections and it is well known for chronically colonising the respiratory tract of patients with cystic fibrosis, causing severe intermittent exacerbation of the condition. P. aeruginosa may appear in the free form cell but also grows in biofilm communities adhered to a surface. An alternative to conventional antimicrobial agents are nanoparticles that can act as carriers for antibiotics and other drugs. In this context, the study aimed to characterise and verify the anti-biofilm potential of GML Nanocapsules against P. aeruginosa. The nanocapsules showed a mean diameter of 190.7 nm, polydispersion index of 0.069, the zeta potential of -23.3 mV. The microdilution test showed a MIC of 62.5 μg/mL to GML and 15.62 μg/mL to GML Nanocapsules. The anti-biofilm experiments demonstrated the significant reduction of biomass, proteins, polysaccharide and viable P. aeruginosa in biofilm treated with GML Nanocapsules while the free GML did not cause an effect. The AFM images showed a decrease in a biofilm which received GML. The positive results suggest an alternative for the public health trouble related to infections associated with biofilm.}, } @article {pmid30861212, year = {2019}, author = {Kugaji, MS and Kumbar, VM and Peram, MR and Patil, S and Bhat, KG and Diwan, PV}, title = {Effect of Resveratrol on biofilm formation and virulence factor gene expression of Porphyromonas gingivalis in periodontal disease.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {127}, number = {4}, pages = {187-195}, doi = {10.1111/apm.12930}, pmid = {30861212}, issn = {1600-0463}, mesh = {Adhesins, Bacterial/analysis ; Anti-Bacterial Agents/*pharmacology ; Bacteroidaceae Infections/microbiology ; Biofilms/*drug effects ; Cysteine Endopeptidases/analysis ; Fimbriae Proteins/analysis ; Gene Expression Profiling ; Gentian Violet/analysis ; Gingipain Cysteine Endopeptidases ; Humans ; Microbial Sensitivity Tests ; Periodontal Diseases/microbiology ; Porphyromonas gingivalis/*drug effects/isolation & purification ; Resveratrol/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Staining and Labeling ; Virulence Factors/*antagonists & inhibitors ; }, abstract = {Periodontal disease is an oral inflammatory disease that destroys the tooth supporting periodontal tissues resulting in tooth loss. Porphyromonas gingivalis is a keystone pathogen that plays a significant role in periodontitis. In previous studies, resveratrol has shown significant results by targeting inflammatory and adhesive markers. Virulence factors of P. gingivalis play an important role in the bacterial adhesion and colonization. In this study, we aimed to demonstrate the anti-biofilm and anti-bacterial activity of resveratrol and also study the effect of resveratrol on the expression of virulence factor genes of P. gingivalis using reverse transcriptase polymerase chain reaction (RT-PCR). The anti-microbial and anti-biofilm activity of resveratrol on P. gingivalis was carried out by broth microdilution assay and biofilm adhesion reduction-crystal violet assay, respectively. We carried out the gene expression analysis by RT-PCR with the P. gingivalis treated compound to analyze the change in the expression of virulence factors: fimbriae and gingipain. Minimal inhibitory concentrations (MIC) of resveratrol against P. gingivalis and other clinical strains are in the range of 78.12-156.25 μg/mL. Resveratrol dose-dependently prevented the biofilm formation and also attenuated the virulence of P. gingivalis by reducing the expression of virulence factor genes such as fimbriae (type II and IV) and proteinases (kgp and rgpA). Resveratrol demonstrated superior anti-bacterial and anti-biofilm activity against P. gingivalis. There was significant reduction in the expression of fimbriae and gingipain with the resveratrol-treated compound. The results suggest that resveratrol, due to its multiple actions, may become a simple and inexpensive therapeutic strategy for treating periodontal disease.}, } @article {pmid30860848, year = {2019}, author = {de Miguel, I and Prieto, I and Albornoz, A and Sanz, V and Weis, C and Turon, P and Quidant, R}, title = {Plasmon-Based Biofilm Inhibition on Surgical Implants.}, journal = {Nano letters}, volume = {19}, number = {4}, pages = {2524-2529}, doi = {10.1021/acs.nanolett.9b00187}, pmid = {30860848}, issn = {1530-6992}, mesh = {Anti-Bacterial Agents/chemistry/therapeutic use ; Biofilms/*drug effects/growth & development ; Disinfection/*methods ; Gold/chemistry ; Herniorrhaphy/methods ; Humans ; Microscopy, Confocal ; Nanoparticles/*administration & dosage/chemistry ; Nanotubes/chemistry ; Prostheses and Implants/adverse effects/microbiology ; Staphylococcus aureus/*drug effects/growth & development/pathogenicity ; Surgical Mesh/microbiology ; }, abstract = {The insertion of an implant in the body of a patient raises the risk of a posterior infection and formation of a biofilm, which can have critical consequences on the patient's health and be associated with a high sanitary cost. While antibacterial agents can be used to prevent the infection, such a strategy is time-limited and causes bacteria resistance. As an alternative to biochemical approaches, we propose here to use light-induced local hyperthermia with plasmonic nanoparticles. This strategy is implemented on surgical meshes, extensively used in the context of hernia repairing, one of the most common general surgeries. Surgical meshes were homogeneously coated with gold nanorods designed to efficiently convert near-infrared light into heat. The modified mesh was exposed to a biofilm of Staphylococcus aureus (S. aureus) bacteria before being treated with a train of light pulses. We systematically study how the illumination parameters, namely fluence, peak intensity and pulse length, influence the elimination of attached bacteria. Additionally, fluorescence confocal microscopy provides us some insight on the mechanism involved in the degradation of the biofilm. This proof-of-principle study opens a new set of opportunities for the development of novel disinfection approaches combining light and nanotechnology.}, } @article {pmid30858842, year = {2019}, author = {Butini, ME and Abbandonato, G and Di Rienzo, C and Trampuz, A and Di Luca, M}, title = {Isothermal Microcalorimetry Detects the Presence of Persister Cells in a Staphylococcus aureus Biofilm After Vancomycin Treatment.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {332}, pmid = {30858842}, issn = {1664-302X}, abstract = {Staphylococcus aureus biofilm plays a major role in implant-associated infections. Here, the susceptibility of biofilm S. aureus to daptomycin, fosfomycin, vancomycin, trimethoprim/sulfamethoxazole, linezolid, and rifampicin was investigated by isothermal microcalorimetry (IMC). Moreover, the persister status of cells isolated from S. aureus biofilm after treatment with vancomycin was also analyzed. S. aureus biofilm was tolerant to all the antibiotics tested [minimum biofilm bactericidal concentration (MBBC) > 256 μg/ml], except to daptomycin [MBBC and minimum biofilm eradicating concentration (MBEC) = 32 μg/ml] and rifampin (MBBC and MBEC = 128 μg/ml). After the treatment of MRSA biofilm with 1024 μg/ml vancomycin, ∼5% cells survived, although metabolically inactive (persisters). Interestingly, IMC revealed that persister bacteria reverted to a normal-growing phenotype when inoculated into fresh medium without antibiotics. A staggered treatment of MRSA biofilm with vancomycin to kill all the metabolically active cells and daptomycin to kill persister cells eradicated the whole bacterial population. These results support the use in the clinical practice of a therapeutic regimen based on the use of two antibiotics to kill persister cells and eradicate MRSA biofilms. IMC represents a suitable technique to characterize in real-time the reversion from persister to metabolically-active cells.}, } @article {pmid30858304, year = {2019}, author = {Valle, J and Echeverz, M and Lasa, I}, title = {σ[B] Inhibits Poly-N-Acetylglucosamine Exopolysaccharide Synthesis and Biofilm Formation in Staphylococcus aureus.}, journal = {Journal of bacteriology}, volume = {201}, number = {11}, pages = {}, pmid = {30858304}, issn = {1098-5530}, mesh = {Amidohydrolases/genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Humans ; Operon ; Polysaccharides, Bacterial/*biosynthesis/genetics ; RNA Stability ; RNA, Messenger/*genetics/metabolism ; Sigma Factor/*genetics/metabolism ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*genetics/isolation & purification/metabolism ; Transcription, Genetic ; }, abstract = {Staphylococcus aureus clinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of the polysaccharide intercellular adhesin (PIA) or poly-N-acetylglucosamine (PNAG), whose synthesis is mediated by the icaADBC locus, and biofilm matrixes built of proteins (polysaccharide independent). σ[B] is a conserved alternative sigma factor that regulates the expression of more than 100 genes in response to changes in environmental conditions. While numerous studies agree that σ[B] is required for polysaccharide-independent biofilms, controversy persists over the role of σ[B] in the regulation of PIA/PNAG-dependent biofilm development. Here, we show that genetically unrelated S. aureus σ[B]-deficient strains produced stronger biofilms under both static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild-type strains. The increased accumulation of PIA/PNAG in the σ[B] mutants correlated with a greater accumulation of the IcaC protein showed that it was not due to adjustments in icaADBC operon transcription and/or icaADBC mRNA stability. Overall, our results reveal that in the presence of active σ[B], the turnover of Ica proteins is accelerated, reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG-dependent biofilm formation capacity.IMPORTANCE Due to its multifaceted lifestyle, Staphylococcus aureus needs a complex regulatory network to connect environmental signals with cellular physiology. One particular transcription factor, named σ[B] (SigB), is involved in the general stress response and the expression of virulence factors. For many years, great confusion has existed about the role of σ[B] in the regulation of the biofilm lifestyle in S. aureus Our study demonstrated that σ[B] is not necessary for exopolysaccharide-dependent biofilms and, even more, that S. aureus produces stronger biofilms in the absence of σ[B] The increased accumulation of exopolysaccharide correlates with higher stability of the proteins responsible for its synthesis. The present findings reveal an additional regulatory layer to control biofilm exopolysaccharide synthesis under stress conditions.}, } @article {pmid30858288, year = {2019}, author = {Wong, SS and Lau, WY and Chan, PK and Wan, CK and Cheng, YL}, title = {Extended Experience in the Use of Antibiotic Lock for Eradication of Biofilm Bacteria on Tenckhoff Catheter.}, journal = {Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis}, volume = {39}, number = {2}, pages = {187-190}, doi = {10.3747/pdi.2018.00098}, pmid = {30858288}, issn = {1718-4304}, mesh = {Anti-Bacterial Agents/*administration & dosage/analysis/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/*microbiology/*prevention & control ; *Catheters, Indwelling ; Hemodialysis Solutions/chemistry ; Humans ; Peritoneal Dialysis/*instrumentation ; Peritonitis/*microbiology/*prevention & control ; }, abstract = {Whilst antibiotic lock is effective to eradicate biofilm bacteria on hemodialysis catheters, this adjunctive method has scarcely been tested in peritoneal dialysis (PD) patients. After our previous successful experience of its use to salvage two Tenckhoff catheters, we encountered another patient with problematic biofilm-associated PD peritonitis who strongly refused catheter removal. As a result, antibiotic lock was given once daily, initially, with continuation of the usual PD schedule. However, relapsing peritonitis could not be prevented until we administered antibiotic lock without dialysate in the abdomen, which led to successful eradication of biofilm bacteria. To investigate the significance of having "dry abdomen" during antibiotic lock treatment, we injected an equivalent amount of contrast into the Tenckhoff catheter under fluoroscopy. We observed that the catheter lock solution could be retained over a long period of time only with "dry abdomen," whereas rapid dissipation of the lock solution occurred in the presence of dialysate. We concluded that whilst antibiotic lock in a once-daily regimen can be highly effective against biofilm bacteria on a Tenckhoff catheter, it is essential to withhold PD exchanges during the dwell of antibiotic lock to prevent it from dissolving into the surrounding dialysate.}, } @article {pmid30856522, year = {2019}, author = {Di Tommaso, C and Taylor-Edmonds, L and Andrews, SA and Andrews, RC}, title = {The contribution of biofilm to nitrogenous disinfection by-product formation in full-scale cyclically-operated drinking water biofilters.}, journal = {Water research}, volume = {155}, number = {}, pages = {403-409}, doi = {10.1016/j.watres.2019.02.025}, pmid = {30856522}, issn = {1879-2448}, mesh = {Biofilms ; Dimethylnitrosamine ; Disinfection ; *Drinking Water ; Nitrogen ; *Water Pollutants, Chemical ; *Water Purification ; }, abstract = {Biofiltration has been shown to be effective for disinfection by-product (DBP) precursor control, however few studies have considered its role in the potential formation of DBPs. Biofilm is composed of heterogeneous bacteria as well as extracellular polymeric substances (EPS). The objective of this study was to determine the contribution of biofilm-related materials such as EPS to form nitrogen-containing DBPs upon chloramination, and to determine the influence of cyclical (scheduled on-off) biofilter operation on DBP precursor removal. Biologically active media was sampled from a full-scale biofilter operating under cold-water conditions (3.6 ± 0.5 °C) and extracted using a cation exchange resin into a phosphate buffer solution. Biomass concentrations, as determined using adenosine triphosphate (ATP) measurements, remained stable at 298 ± 55 ng ATP/g media over the trial period. N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) formation potential (FP) tests conducted under uniform formation conditions (UFC) using extracted biofilm yielded 0.80 ± 0.27 ng NDMA/g media and 18.7 ± 3.3 ng dichloroacetonitrile (DCAN)/g media. Further analyses of extracted biofilm using fluorescence spectroscopy and liquid chromatography-organic carbon detection indicated the presence of proteins above 20 kDa and humic-like substances. Extracted proteins (93.5 ± 8.1 μg/g media) correlated well (R = 0.90) with UV 280 measurements, indicating that spectrophotometry may serve as a valuable tool to quantify proteins in extracted biofilms. While substances in biofilms can serve as NDMA and DCAN precursors, the full-scale cyclically-operated biofilter that was examined did not show release of NDMA precursors during start-up following stagnation periods of 6 h or more. These biofilters consistently removed 6.9 ± 4.3 ng/L of NDMA precursors; typical NDMA UFC-FP of biofilter effluent was 8.5 ± 2.6 ng/L.}, } @article {pmid30856240, year = {2019}, author = {Pakkulnan, R and Anutrakunchai, C and Kanthawong, S and Taweechaisupapong, S and Chareonsudjai, P and Chareonsudjai, S}, title = {Extracellular DNA facilitates bacterial adhesion during Burkholderia pseudomallei biofilm formation.}, journal = {PloS one}, volume = {14}, number = {3}, pages = {e0213288}, pmid = {30856240}, issn = {1932-6203}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Burkholderia pseudomallei/*pathogenicity ; DNA, Bacterial/analysis/*physiology ; Extracellular Space ; Humans ; Melioidosis/*microbiology ; }, abstract = {The biofilm-forming ability of Burkholderia pseudomallei is crucial for its survival in unsuitable environments and is correlated with antibiotic resistance and relapsing cases of melioidosis. Extracellular DNA (eDNA) is an essential component for biofilm development and maturation in many bacteria. The aim of this study was to investigate the eDNA released by B. pseudomallei during biofilm formation using DNase treatment. The extent of biofilm formation and quantity of eDNA were assessed by crystal-violet staining and fluorescent dye-based quantification, respectively, and visualized by confocal laser scanning microscopy (CLSM). Variation in B. pseudomallei biofilm formation and eDNA quantity was demonstrated among isolates. CLSM images of biofilms stained with FITC-ConA (biofilm) and TOTO-3 (eDNA) revealed the localization of eDNA in the biofilm matrix. A positive correlation of biofilm biomass with quantity of eDNA during the 2-day biofilm-formation observation period was found. The increasing eDNA quantity over time, despite constant living/dead ratios of bacterial cells during the experiment suggests that eDNA is delivered from living bacterial cells. CLSM images demonstrated that depletion of eDNA by DNase I significantly lessened bacterial attachment (if DNase added at 0 h) and biofilm developing stages (if added at 24 h) but had no effect on mature biofilm (if added at 45 h). Collectively, our results reveal that eDNA is released from living B. pseudomallei and is correlated with biofilm formation. It was also apparent that eDNA is essential during bacterial cell attachment and biofilm-forming steps. The depletion of eDNA by DNase may provide an option for the prevention or dispersal of B. pseudomallei biofilm.}, } @article {pmid30855125, year = {2019}, author = {Aldrich, A and Kuss, MA and Duan, B and Kielian, T}, title = {3D Bioprinted Scaffolds Containing Viable Macrophages and Antibiotics Promote Clearance of Staphylococcus aureus Craniotomy-Associated Biofilm Infection.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {13}, pages = {12298-12307}, pmid = {30855125}, issn = {1944-8252}, support = {P30 CA036727/CA/NCI NIH HHS/United States ; R01 NS107369/NS/NINDS NIH HHS/United States ; }, mesh = {Animals ; *Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/drug effects/growth & development ; Cell Line ; *Craniotomy ; Female ; Humans ; *Macrophages/metabolism/pathology ; Male ; Mice ; *Printing, Three-Dimensional ; *Staphylococcal Infections/metabolism/pathology/therapy ; Staphylococcus aureus/*physiology ; *Wound Infection/metabolism/microbiology/pathology/therapy ; }, abstract = {Craniotomy involves the removal of a skull fragment to access the brain, such as during tumor or epilepsy surgery, which is immediately replaced intraoperatively. The infection incidence after craniotomy ranges from 0.8 to 3%, with approximately half caused by Staphylococcus aureus (S. aureus). To mitigate infectious complications following craniotomy, we engineered a three-dimensional (3D) bioprinted bone scaffold to harness the potent antibacterial activity of macrophages (MΦs) together with antibiotics using a mouse S. aureus craniotomy-associated biofilm model that establishes a persistent infection on the bone flap, subcutaneous galea, and brain. The 3D scaffold contained rifampin and daptomycin printed in a composite slurry, with viable MΦs incorporated into a hydrogel-based bioink, which was assessed for both the treatment and prevention of craniotomy-associated infections in the mouse model. For the treatment paradigm, the bone flap was removed at day 7 post infection after a mature biofilm had formed and was replaced with a 3D printed antibiotic scaffold, with or without MΦ incorporation. Bacterial burdens in the galea and brain were reduced by at least 100-fold at early time points, which was potentiated by bioprinting viable MΦs into the 3D antibiotic scaffold. We also examined a prevention paradigm, where the scaffolds were placed at the time of surgery and challenged with S. aureus one day later at the surgical site. Interestingly, unlike the treatment paradigm, the incorporation of viable MΦs into the 3D antibiotic scaffold did not enhance bacterial clearance compared to that of antibiotic alone. With further refinement, our 3D bioprinted scaffold represents a potential treatment modality, as it delivers therapeutic antibiotic levels more rapidly than systemic administration, based on its proximity to the infection site. In addition, the incorporation of viable MΦs into the 3D scaffold is an important advance, which demonstrated an improved therapeutic benefit for the treatment of established biofilms that represent the most clinically challenging scenario.}, } @article {pmid30853939, year = {2019}, author = {Hussain, A and Alajmi, MF and Khan, MA and Pervez, SA and Ahmed, F and Amir, S and Husain, FM and Khan, MS and Shaik, GM and Hassan, I and Khan, RA and Rehman, MT}, title = {Biosynthesized Silver Nanoparticle (AgNP) From Pandanus odorifer Leaf Extract Exhibits Anti-metastasis and Anti-biofilm Potentials.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {8}, pmid = {30853939}, issn = {1664-302X}, abstract = {Cancer and the associated secondary bacterial infections are leading cause of mortality, due to the paucity of effective drugs. Here, we have synthesized silver nanoparticles (AgNPs) from organic resource and confirmed their anti-cancer and anti-microbial potentials. Microwave irradiation method was employed to synthesize AgNPs using Pandanus odorifer leaf extract. Anti-cancer potential of AgNPs was evaluated by scratch assay on the monolayer of rat basophilic leukemia (RBL) cells, indicating that the synthesized AgNPs inhibit the migration of RBL cells. The synthesized AgNPs showed MIC value of 4-16 μg/mL against both Gram +ve and Gram -ve bacterial strains, exhibiting the anti-microbial potential. Biofilm inhibition was recorded at sub-MIC values against Gram +ve and Gram -ve bacterial strains. Violacein and alginate productions were reduced by 89.6 and 75.6%, respectively at 4 and 8 μg/mL of AgNPs, suggesting anti-quorum sensing activity. Exopolysaccharide production was decreased by 61-79 and 84% for Gram -ve and Gram +ve pathogens respectively. Flagellar driven swarming mobility was also reduced significantly. Furthermore, In vivo study confirmed their tolerability in mice, indicating their clinical perspective. Collective, we claim that the synthesized AgNPs have anti-metastasis as well as anti-microbial activities. Hence, this can be further tested for therapeutic options to treat cancer and secondary bacterial infections.}, } @article {pmid30853830, year = {2019}, author = {Novotny, LA and Brockman, KL and Mokrzan, EM and Jurcisek, JA and Bakaletz, LO}, title = {Biofilm biology and vaccine strategies for otitis media due to nontypeable Haemophilus influenzae.}, journal = {Journal of pediatric infectious diseases}, volume = {14}, number = {2}, pages = {69-77}, pmid = {30853830}, issn = {1305-7707}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 DC015688/DC/NIDCD NIH HHS/United States ; }, abstract = {Otitis media (OM) is one of the most common diseases of childhood, and nontypeable Haemophilus influenzae (NTHI) is the predominant causative agent of chronic and recurrent OM, as well as OM for which treatment has failed. Moreover, NTHI is now as important a causative agent of acute OM as the pneumococcus. NTHI colonizes the human nasopharynx asymptomatically. However, upon perturbation of the innate and physical defenses of the airway by upper respiratory tract viral infection, NTHI can replicate, ascend the Eustachian tube, gain access to the normally sterile middle ear space, and cause disease. Bacterial biofilms within the middle ear, including those formed by NTHI, contribute to the chronic and recurrent nature of this disease. These multicomponent structures are highly resistant to clearance by host defenses and elimination by traditional antimicrobial therapies. Herein, we review several strategies utilized by NTHI in order to persist within the human host and interventions currently under investigation to prevent and/or resolve NTHI-induced diseases of the middle ear and uppermost airway.}, } @article {pmid30852214, year = {2019}, author = {Meng, Y and Sheng, B and Meng, F}, title = {Changes in nitrogen removal and microbiota of anammox biofilm reactors under tetracycline stress at environmentally and industrially relevant concentrations.}, journal = {The Science of the total environment}, volume = {668}, number = {}, pages = {379-388}, doi = {10.1016/j.scitotenv.2019.02.389}, pmid = {30852214}, issn = {1879-1026}, mesh = {Biofilms/*drug effects/growth & development ; Denitrification/*drug effects ; Nitrogen/*analysis ; Tetracycline/toxicity ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Pollutants, Chemical/toxicity ; }, abstract = {Anammox-related processes are often applied for the wastewater treatment which contains both ammonium and antibiotics. Herein, the long-term effects of tetracycline (TC), at environmentally and industrially relevant concentrations, on the performance, anammox activity and microbial community of anammox reactors were investigated for 518 days. The control reactor (without TC exposure) was stable for nitrogen removal during the long-term operation (a nitrogen removal rate of 0.56 ± 0.05 kg-N·m[-3]·d[-1]). In the TC-added reactor, the nitrogen removal efficiency increased slightly at low TC levels (1-100 μg/L), whereas poor anammox performance occurred at high TC concentration (1000 μg/L). Furthermore, the concentrations of extracellular polymeric substances (EPS) were much higher at 10 μg/L than those in the control reactor (P < 0.01), whereas rapidly decreased at 1000 μg-TC/L. Furthermore, the reactor performance was highly consistent with the variations of the heme c contents. Consistently, exposure to TC changed the abundance of anammox bacteria, e.g., an increase in Candidatus Jettenia abundance occurred from 2.20 ± 0.97% (0-10 μg/L) to 12.13 ± 1.66% (100 μg/L). Similarly, the genus Denitratisoma, the most predominant denitrification bacteria, also had a higher abundance at a TC concentration of 100 μg/L (15.60 ± 6.42%) than other TC concentrations (5.40 ± 2.50% and 7.65 ± 0.55% at concentrations of 10 and 1000 μg/L, respectively). The results can explain why the exposure of anammox bacteria to a lower TC concentration (100 μg/L) resulted in a better nitrogen removal rate. In contrast, exposure to a high TC level (1000 μg/L) led to a decline in the abundance of anammox bacteria and denitrifiers (1.53 ± 0.64% and 8.18 ± 0.63%, respectively) but an increased abundance in the nitrifier population (8.07 ± 1.21%; P < 0.01). Therefore, this study can aid in the design and operation of anammox-based processes treating sewage and industrial wastewater.}, } @article {pmid30851643, year = {2019}, author = {Skowron, K and Wiktorczyk, N and Grudlewska, K and Kwiecińska-Piróg, J and Wałecka-Zacharska, E and Paluszak, Z and Gospodarek-Komkowska, E}, title = {Drug-susceptibility, biofilm-forming ability and biofilm survival on stainless steel of Listeria spp. strains isolated from cheese.}, journal = {International journal of food microbiology}, volume = {296}, number = {}, pages = {75-82}, doi = {10.1016/j.ijfoodmicro.2019.02.021}, pmid = {30851643}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Cheese/*microbiology ; Disk Diffusion Antimicrobial Tests ; Food Contamination/analysis ; Food Handling ; Food Microbiology ; Listeria monocytogenes/*drug effects/genetics/*growth & development/isolation & purification ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; *Stainless Steel ; }, abstract = {The aim of the study was to analyze the contamination of mold cheese (Brie, Camembert, Gorgonzola, Munster and Roquefort) with Listeria spp. and assessment of culturable cells number recovered from the biofilm formed on the surface of stainless steel by obtained strains. Identified isolates (MALDI TOF MS technique) were subjected to susceptibility testing (disk-diffusion method) and their genetic similarity (PFGE method), ability to form biofilm (quantitative method), biofilm dry weight, and biofilm survival on stainless steel were evaluated. Out of 250 samples of cheese 26 (10.4%) were Listeria spp. positive, including 15 isolates (6.0% of samples) of L. monocytogenes, 7 isolates of L. innocua (2.8% of samples) and 4 isolates of L. welshimeri species (1.6% of samples). Of the 26 isolates tested, 22 strains were genetically different. It was shown that L. innocua and L. welshimeri strains were sensitive to all antibiotics tested, while two (16.7%) L. monocytogenes strains were resistant to penicillin and one (8.3%) to erythromycin. L. monocytogenes formed biofilm most intensively on stainless steel, while L. welshimeri the least effectively. The median of bacteria number recovered from the biofilm for L. monocytogenes was 6.81 log CFU × cm[-2], for L. innocua - 5.63 log CFU × cm[-2], and for L. welshimeri - 4.93 log CFU × cm[-2]. The survival in the biofilm of Listeria spp. strains decreased along with the increase in a storage temperature of steel coupons. The longest survival time was reported at 4 °C, i.e. 47.58-124.41 days, with an elimination rate of 0.06-0.13 log CFU × day[-1]. Collectively, L. monocytogenes is the most prevalent species of Listeria genus in the mold cheese. The ability of L. monocytogenes strains to form biofilm on stainless steel and survive in the food processing environment increases chance of the secondary contamination of food posing risk to the consumer health.}, } @article {pmid30851361, year = {2019}, author = {Calvillo-Medina, RP and Reyes-Grajeda, JP and Barba-Escoto, L and Bautista-Hernandez, LA and Campos-Guillén, J and Jones, GH and Bautista-de Lucio, VM}, title = {Proteome analysis of biofilm produced by a Fusarium falciforme keratitis infectious agent.}, journal = {Microbial pathogenesis}, volume = {130}, number = {}, pages = {232-241}, doi = {10.1016/j.micpath.2019.03.001}, pmid = {30851361}, issn = {1096-1208}, mesh = {Biofilms/*growth & development ; Cornea/microbiology ; Electrophoresis, Gel, Two-Dimensional ; Eye Infections, Fungal/microbiology ; Fungal Proteins/*analysis ; Fusariosis/microbiology ; Fusarium/*chemistry/*growth & development/isolation & purification ; Humans ; Keratitis/microbiology ; Mass Spectrometry ; Proteome/*analysis ; }, abstract = {Biofilms are structures that confer adaptive ability to and facilitate the virulence of fungal pathogens. Certain multi-functional proteins have been shown to be involved in fungal pathogenesis and these proteins may also be implicated in biofilm formation. The aim of this study was to identify a fungal agent isolated from the human cornea, to analyze the ability of this organism to form biofilms in vitro and to investigate protein expression in this condition. The fungus was identified by phylogenetic inference analysis. Biofilm formation and structure were evaluated by colorimetric methods and by optical and electron microscopy. We also resolved proteins obtained from biofilms and planktonic cultures by two-dimensional gel electrophoresis and identified those proteins by mass spectrometry. The fungus was identified as Fusarium falciforme. Colorimetric analysis and microscopy revealed that the highest level of biofilm formation was obtained at a concentration of 1 × 10[6] conidia/mL with 96 h of incubation at 28 °C. The biofilm architecture consisted of an extracellular matrix that embedded fungal filaments. We found nineteen proteins that were over-expressed in biofilms, as compared with planktonic cultures, and six proteins with unique expression in biofilms. Among the more abundant proteins identified were: transketolase, a putative antigen 1, enolase, phosphoglycerate kinase and ATP-citrate synthase. Some of these proteins are involved in basal metabolism, function as multi-functional proteins or have been described as potential virulence factors. We focused on the expression in biofilm of the enzyme, enolase, which was determined by real-time PCR. Our findings provide a perspective on the proteins associated with the formation of biofilms in vitro by an F. falciforme keratitis isolate.}, } @article {pmid30850421, year = {2019}, author = {Graf, AC and Leonard, A and Schäuble, M and Rieckmann, LM and Hoyer, J and Maass, S and Lalk, M and Becher, D and Pané-Farré, J and Riedel, K}, title = {Virulence Factors Produced by Staphylococcus aureus Biofilms Have a Moonlighting Function Contributing to Biofilm Integrity.}, journal = {Molecular & cellular proteomics : MCP}, volume = {18}, number = {6}, pages = {1036-1053}, pmid = {30850421}, issn = {1535-9484}, mesh = {Acids/metabolism ; Animals ; Bacterial Proteins/*metabolism ; *Biofilms ; DNA, Bacterial/metabolism ; Extracellular Matrix/drug effects/metabolism ; Metabolome ; Models, Biological ; Moths/microbiology ; Osmotic Pressure ; Oxygen/pharmacology ; Phenotype ; Plankton/cytology ; Rabbits ; Ribosomal Proteins/metabolism ; Staphylococcus aureus/cytology/*metabolism/*physiology ; Virulence Factors/*metabolism ; }, abstract = {Staphylococcus aureus is the causative agent of various biofilm-associated infections in humans causing major healthcare problems worldwide. This type of infection is inherently difficult to treat because of a reduced metabolic activity of biofilm-embedded cells and the protective nature of a surrounding extracellular matrix (ECM). However, little is known about S. aureus biofilm physiology and the proteinaceous composition of the ECM. Thus, we cultivated S. aureus biofilms in a flow system and comprehensively profiled intracellular and extracellular (ECM and flow-through (FT)) biofilm proteomes, as well as the extracellular metabolome compared with planktonic cultures. Our analyses revealed the expression of many pathogenicity factors within S. aureus biofilms as indicated by a high abundance of capsule biosynthesis proteins along with various secreted virulence factors, including hemolysins, leukotoxins, and lipases as a part of the ECM. The activity of ECM virulence factors was confirmed in a hemolysis assay and a Galleria mellonella pathogenicity model. In addition, we uncovered a so far unacknowledged moonlighting function of secreted virulence factors and ribosomal proteins trapped in the ECM: namely their contribution to biofilm integrity. Mechanistically, it was revealed that this stabilizing effect is mediated by the strong positive charge of alkaline virulence factors and ribosomal proteins in an acidic ECM environment, which is caused by the release of fermentation products like formate, lactate, and acetate because of oxygen limitation in biofilms. The strong positive charge of these proteins most likely mediates electrostatic interactions with anionic cell surface components, eDNA, and anionic metabolites. In consequence, this leads to strong cell aggregation and biofilm stabilization. Collectively, our study identified a new molecular mechanism during S. aureus biofilm formation and thus significantly widens the understanding of biofilm-associated S. aureus infections - an essential prerequisite for the development of novel antimicrobial therapies.}, } @article {pmid30848779, year = {2019}, author = {Osorio, JHM and Benettoni, P and Schmidt, M and Stryhanyuk, H and Schmitt-Jansen, M and Pinto, G and Pollio, A and Frunzo, L and Lens, PNL and Richnow, HH and Esposito, G and Musat, N}, title = {Investigation of architecture development and phosphate distribution in Chlorella biofilm by complementary microscopy techniques.}, journal = {FEMS microbiology ecology}, volume = {95}, number = {4}, pages = {}, doi = {10.1093/femsec/fiz029}, pmid = {30848779}, issn = {1574-6941}, mesh = {Biofilms/*growth & development ; Chlorella/*metabolism/physiology/ultrastructure ; Microalgae/*metabolism/physiology/ultrastructure ; Microscopy/methods ; Phosphates/*metabolism ; Phosphorus/metabolism ; Spectrometry, Mass, Secondary Ion ; Waste Disposal, Fluid ; }, abstract = {Microalgae biofilms may play an important role in the mitigation and prevention of eutrophication caused by domestic, agricultural and industrial wastewater effluents. Despite their potential, the biofilm development and role in nutrient removal are not well understood. Its clarification requires comprehensive studies of the complex three-dimensional architecture of the biofilm. In this study, we established a multimodal imaging approach to provide key information regarding architecture development and nutrient distribution in the biofilm of two green algae organisms: Chlorella pyrenoidosa and Chlorella vulgaris. Helium ion microscopy (HIM), scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed for i) elucidation of spatial arrangement, ii) elemental mapping and iii) 3D chemical imaging of the biofilm. The fine structure of the algal biofilm was resolved by HIM, the evidence of the accumulation of phosphate in hot spots was provided by SEM-EDX and the localization of phosphate oxides granules throughout the whole sample was clarified by ToF-SIMS. The reported results shed light on the phosphorus distribution during Chlorella's biofilm formation and highlight the potential of such correlative approach to solve fundamental question in algal biotechnology research.}, } @article {pmid30848725, year = {2019}, author = {Yan, J and Fei, C and Mao, S and Moreau, A and Wingreen, NS and Košmrlj, A and Stone, HA and Bassler, BL}, title = {Mechanical instability and interfacial energy drive biofilm morphogenesis.}, journal = {eLife}, volume = {8}, number = {}, pages = {}, pmid = {30848725}, issn = {2050-084X}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; DMR-1420541//National Science Foundation/International ; Career Award at the Scientific Interface 1015763//Burroughs Wellcome Fund/International ; 2R37GM065859/NH/NIH HHS/United States ; MCB-1344191//National Science Foundation/International ; MCB-1713731//National Science Foundation/International ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; *Mechanical Phenomena ; Vibrio cholerae/*growth & development ; }, abstract = {Surface-attached bacterial communities called biofilms display a diversity of morphologies. Although structural and regulatory components required for biofilm formation are known, it is not understood how these essential constituents promote biofilm surface morphology. Here, using Vibrio cholerae as our model system, we combine mechanical measurements, theory and simulation, quantitative image analyses, surface energy characterizations, and mutagenesis to show that mechanical instabilities, including wrinkling and delamination, underlie the morphogenesis program of growing biofilms. We also identify interfacial energy as a key driving force for mechanomorphogenesis because it dictates the generation of new and the annihilation of existing interfaces. Finally, we discover feedback between mechanomorphogenesis and biofilm expansion, which shapes the overall biofilm contour. The morphogenesis principles that we discover in bacterial biofilms, which rely on mechanical instabilities and interfacial energies, should be generally applicable to morphogenesis processes in tissues in higher organisms.}, } @article {pmid30847714, year = {2019}, author = {Azman, AS and Mawang, CI and Khairat, JE and AbuBakar, S}, title = {Actinobacteria-a promising natural source of anti-biofilm agents.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {22}, number = {4}, pages = {403-409}, doi = {10.1007/s10123-019-00066-4}, pmid = {30847714}, issn = {1618-1905}, support = {GA004-2018//Yayasan Pahang/ ; }, mesh = {Actinobacteria/*chemistry/metabolism ; Anti-Bacterial Agents/chemistry/metabolism/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Biological Products/chemistry/metabolism/*pharmacology ; }, abstract = {A biofilm is a community of microorganisms attached to a surface and embedded in a matrix of extracellular polymeric substances. Biofilms confer resistance towards conventional antibiotic treatments; thus, there is an urgent need for newer and more effective antimicrobial agents that can act against these biofilms. Due to this situation, various studies have been done to investigate the anti-biofilm effects of natural products including bioactive compounds extracted from microorganisms such as Actinobacteria. This review provides an insight into the anti-biofilm potential of Actinobacteria against various pathogenic bacteria, which hopefully provides useful information, guidance, and improvements for future antimicrobial studies. Nevertheless, further research on the anti-biofilm mechanisms and compound modifications to produce more potent anti-biofilm effects are required.}, } @article {pmid30847656, year = {2019}, author = {Sahar-Helft, S and Erez, A and Shay, B and Assad, R and Funk, B and Polak, D}, title = {Enhancing Er:YAG bactericidal effect against Enterococcus faecalis biofilm in vitro.}, journal = {Lasers in medical science}, volume = {34}, number = {8}, pages = {1717-1721}, pmid = {30847656}, issn = {1435-604X}, } @article {pmid30847541, year = {2019}, author = {Xiros, C and Shahab, RL and Studer, MH}, title = {A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {8}, pages = {3355-3365}, pmid = {30847541}, issn = {1432-0614}, support = {407040_153868//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (CH)/ ; KTI.2014.0116//Kommission für Technologie und Innovation/ ; }, mesh = {Animals ; *Biofilms/growth & development ; Bioreactors/microbiology ; Cellulose/*metabolism ; Fatty Acids, Volatile/chemistry/*metabolism ; Fermentation ; Fungi/classification/growth & development/*metabolism ; Hydrogen-Ion Concentration ; *Microbiota ; Rumen/*microbiology ; Species Specificity ; Temperature ; }, abstract = {The ability of the multispecies biofilm membrane reactors (MBM reactors) to provide distinguished niches for aerobic and anaerobic microbes at the same time was used for the investigation of the consolidated bioprocessing of cellulose to short chain fatty acids (SCFAs). A consortium based consolidated bioprocess (CBP) was designed. The rumen microbiome was used as the converting microbial consortium, co-cultivated with selected individual aerobic fungi which formed a biofilm on the tubular membrane flushed with oxygen. The beneficial effect of the fungal biofilm on the process yields and productivities was attributed to the enhanced cellulolytic activities compared with those achieved by the rumen microbiome alone. At 30 °C, the MBM system with Trichoderma reesei biofilm reached a concentration 39% higher (7.3 g/L SCFAs), than the rumen microbiome alone (5.1 g/L) using 15 g/L crystalline cellulose as the substrate. Fermentation temperature was crucial especially for the composition of the short chain fatty acids produced. The temperature increase resulted in shorter fatty acids produced. While a mixture of acetic, propionic, butyric, and caproic acids was produced at 30 °C with Trichoderma reesei biofilm, butyric and caproic acids were not detected during the fermentations at 37.5 °C carried out with Coprinopsis cinerea as the biofilm forming fungus. Apart from the presence of the fungal biofilm, no parameter studied had a significant impact on the total yield of organic acids produced, which reached 0.47 g of total SCFAs per g of cellulose (at 30 °C and at pH 6, with rumen inoculum to total volume ratio equal to 0.372).}, } @article {pmid30847048, year = {2019}, author = {Lee, DH and Mai, HN and Thant, PP and Hong, SH and Kim, J and Jeong, SM and Lee, KW}, title = {Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation.}, journal = {The journal of advanced prosthodontics}, volume = {11}, number = {1}, pages = {41-47}, pmid = {30847048}, issn = {2005-7806}, abstract = {PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence.

MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05).

RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P<.001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment.

CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.}, } @article {pmid30844070, year = {2019}, author = {Fritz, B and Stavnsbjerg, C and Markvart, M and Damgaard, PB and Nielsen, SH and Bjørndal, L and Qvortrup, K and Bjarnsholt, T}, title = {Shotgun sequencing of clinical biofilm following scanning electron microscopy identifies bacterial community composition.}, journal = {Pathogens and disease}, volume = {77}, number = {1}, pages = {}, doi = {10.1093/femspd/ftz013}, pmid = {30844070}, issn = {2049-632X}, mesh = {Bacteria/*classification/*genetics/ultrastructure ; Biodiversity ; *Biofilms ; Humans ; *Metagenome ; *Metagenomics ; }, abstract = {Bacterial biofilm infections often involve aggregates of bacteria heterogeneously distributed throughout a tissue or on a surface (such as an implanted medical device). Identification of a biofilm infection requires direct visualization via microscopy, followed by characterization of the microbial community by culturing or sequencing-based approaches. A sample, therefore, must be divided prior to analysis, often leading to inconsistent results. We demonstrate a combined approach, using scanning electron microscopy and next-generation shotgun sequencing, to visually identify a biofilm and characterize the microbial community, without dividing the sample. A clinical sample recovered from a patient following a dental root-filling procedure was prepared and visualized by scanning electron microscopy. DNA was then extracted from the sample several years later and analyzed by shotgun sequencing. The method was subsequently validated on in vitro cultures of Pseudomonas aeruginosa biofilm. Between 19 and 21 different genera and species were identified in the clinical sample with an estimated relative abundance greater than 1% by two different estimation approaches. Only eight genera identified were not associated with endodontic infections. This provides a proof-of-concept for a dual, microscopy and sequencing-based approach to identify and characterize bacterial biofilms, which could also easily be implemented in other scientific fields.}, } @article {pmid30843349, year = {2019}, author = {Zetzmann, M and Bucur, FI and Crauwels, P and Borda, D and Nicolau, AI and Grigore-Gurgu, L and Seibold, GM and Riedel, CU}, title = {Characterization of the biofilm phenotype of a Listeria monocytogenes mutant deficient in agr peptide sensing.}, journal = {MicrobiologyOpen}, volume = {8}, number = {9}, pages = {e00826}, pmid = {30843349}, issn = {2045-8827}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Culture Media/chemistry ; Gene Deletion ; Gene Expression Profiling ; Gene Regulatory Networks ; Listeria monocytogenes/genetics/*growth & development ; *Phenotype ; Temperature ; }, abstract = {Listeria monocytogenes is a food-borne human pathogen and a serious concern in food production and preservation. Previous studies have shown that biofilm formation of L. monocytogenes and presence of extracellular DNA (eDNA) in the biofilm matrix varies with environmental conditions and may involve agr peptide sensing. Experiments in normal and diluted (hypoosmotic) complex media at different temperatures revealed reduced biofilm formation of L. monocytogenes EGD-e ΔagrD, a mutant deficient in agr peptide sensing, specifically in diluted Brain Heart Infusion at 25°C. This defect was not related to reduced sensitivity to DNase treatment suggesting sufficient levels of eDNA. Re-analysis of a previously published transcriptional profiling indicated that a total of 132 stress-related genes, that is 78.6% of the SigB-dependent stress regulon, are differentially expressed in the ΔagrD mutant. Additionally, a number of genes involved in flagellar motility and a large number of other surface proteins including internalins, peptidoglycan binding and cell wall modifying proteins showed agr-dependent gene expression. However, survival of the ΔagrD mutant in hypoosmotic conditions or following exposure to high hydrostatic pressure was comparable to the wild type. Also, flagellar motility and surface hydrophobicity were not affected. However, the ΔagrD mutant displayed a significantly reduced viability upon challenge with lysozyme. These results suggest that the biofilm phenotype of the ΔagrD mutant is not a consequence of reduced resistance to hypoosmotic or high pressure stress, motility or surface hydrophobicity. Instead, agr peptide sensing seems to be required for proper regulation of biosynthesis, structure and function of the cell envelope, adhesion to the substratum, and/or interaction of bacteria within a biofilm.}, } @article {pmid30842579, year = {2019}, author = {Goodwine, J and Gil, J and Doiron, A and Valdes, J and Solis, M and Higa, A and Davis, S and Sauer, K}, title = {Pyruvate-depleting conditions induce biofilm dispersion and enhance the efficacy of antibiotics in killing biofilms in vitro and in vivo.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {3763}, pmid = {30842579}, issn = {2045-2322}, support = {R56 AI127815/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Burns/drug therapy/microbiology ; Culture Media/chemistry ; Disease Models, Animal ; Fermentation ; Humans ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/isolation & purification/*physiology ; Pyruvic Acid/*chemistry ; Staphylococcus aureus/drug effects/*physiology ; Swine ; Tobramycin/*pharmacology/therapeutic use ; }, abstract = {The formation of biofilms is a developmental process initiated by planktonic cells transitioning to the surface, which comes full circle when cells disperse from the biofilm and transition to the planktonic mode of growth. Considering that pyruvate has been previously demonstrated to be required for the formation of P. aeruginosa biofilms, we asked whether pyruvate likewise contributes to the maintenance of the biofilm structure, with depletion of pyruvate resulting in dispersion. Here, we demonstrate that the enzymatic depletion of pyruvate coincided with the dispersion of established biofilms by S. aureus and laboratory and clinical P. aeruginosa isolates. The dispersion response was dependent on pyruvate fermentation pathway components but independent of proteins previously described to contribute to P. aeruginosa biofilm dispersion. Using porcine second-degree burn wounds infected with P. aeruginosa biofilm cells, we furthermore demonstrated that pyruvate depletion resulted in a reduction of biofilm biomass in vivo. Pyruvate-depleting conditions enhanced the efficacy of tobramycin killing of the resident wound biofilms by up to 5-logs. Our findings strongly suggest the management of pyruvate availability to be a promising strategy to combat biofilm-related infections by two principal pathogens associated with wound and cystic fibrosis lung infections.}, } @article {pmid30842268, year = {2019}, author = {Taylor, PK and Zhang, L and Mah, TF}, title = {Loss of the Two-Component System TctD-TctE in Pseudomonas aeruginosa Affects Biofilm Formation and Aminoglycoside Susceptibility in Response to Citric Acid.}, journal = {mSphere}, volume = {4}, number = {2}, pages = {}, pmid = {30842268}, issn = {2379-5042}, mesh = {Aminoglycosides/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; Citric Acid/*pharmacology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*drug effects/*genetics ; Tobramycin/pharmacology ; }, abstract = {The two-component system TctD-TctE is important for regulating the uptake of tricarboxylic acids in Pseudomonas aeruginosa TctD-TctE accomplishes this through derepression of the gene opdH, which encodes a tricarboxylic acid-specific porin. Previous work from our lab revealed that TctD-TctE in P. aeruginosa also has a role in resistance to aminoglycoside antibiotics. The aim of this study was to further characterize the role of TctD-TctE in P. aeruginosa in the presence of citric acid. Here it was found that deletion of P. aeruginosa PA14 TctD-TctE (ΔtctED) resulted in a 4-fold decrease in the biofilm bactericidal concentrations of the aminoglycosides tobramycin and gentamicin when citric acid was present in nutrient media. Tobramycin accumulation assays demonstrated that deletion of TctD-TctE resulted in an increase in the amount of tobramycin retained in biofilm cells. The PA14 wild type responded to increasing concentrations of citric acid by producing less biofilm. In contrast, the amount of ΔtctED mutant biofilm formation remained constant or enhanced. Furthermore, the ΔtctED strain was incapable of growing on citric acid as a sole carbon source and was highly reduced in its ability to grow in the presence of citric acid even when an additional carbon source was available. Use of phenotypic and genetic microarrays found that this growth deficiency of the ΔtctED mutant is unique to citric acid and that multiple metabolic genes are dysregulated. This work demonstrates that TctD-TctE in P. aeruginosa has a role in biofilm development that is dependent on citric acid and that is separate from the previously characterized involvement in resistance to antibiotics.IMPORTANCE Nutrient availability is an important contributor to the ability of bacteria to establish successful infections in a host. Pseudomonas aeruginosa is an opportunistic pathogen in humans causing infections that are difficult to treat. In part, its success is attributable to a high degree of metabolic versatility. P. aeruginosa is able to sense and respond to varied and limited nutrient stress in the host environment. Two-component systems are important sensors-regulators of cellular responses to environmental stresses, such as those encountered in the host. This work demonstrates that the response by the two-component system TctD-TctE to the presence of citric acid has a role in biofilm formation, aminoglycoside susceptibility, and growth in P. aeruginosa.}, } @article {pmid30840533, year = {2019}, author = {Haesler, E and Swanson, T and Ousey, K and Carville, K}, title = {Clinical indicators of wound infection and biofilm: reaching international consensus.}, journal = {Journal of wound care}, volume = {28}, number = {Sup3b}, pages = {s4-s12}, doi = {10.12968/jowc.2019.28.Sup3b.S4}, pmid = {30840533}, issn = {0969-0700}, mesh = {Biofilms ; Delphi Technique ; Global Health ; Humans ; Wound Infection/*diagnosis/microbiology/therapy ; }, abstract = {OBJECTIVE: To achieve international consensus relating to clinical indicators for a chronic wound, wound infection and biofilm presence to inform the development of international clinical guidance for assessing and managing wound infection.

METHOD: An online Delphi consensus process of international key opinion leaders in infection was undertaken. A literature search underpinned the development of issue statements related to terminology, emerging topics and debate in the field of wound infection. Experts participated in three rounds of consensus voting, sharing their opinions and indicating their level of agreement with the issue statements. Votes were calculated using web-based software that implements a nominal group voting methodology previously published by Research and Development/University of California at Los Angeles.

RESULTS: A total of 14 experts took part in the development process. Consensus was reached on clinical indicators of wound chronicity, wound infection and biofilm presence. Agreement was also reached that the term 'critical colonisation' should no longer be used to refer to a stage in the wound infection continuum.

CONCLUSION: Outcomes from the consensus process were used to inform the development of international, evidence-informed guidance on the assessment and treatment of wound infection to promote improved outcomes for people with wounds.}, } @article {pmid30838858, year = {2019}, author = {Hu, MX and Li, JN and Guo, Q and Zhu, YQ and Niu, HM}, title = {Probiotics Biofilm-Integrated Electrospun Nanofiber Membranes: A New Starter Culture for Fermented Milk Production.}, journal = {Journal of agricultural and food chemistry}, volume = {67}, number = {11}, pages = {3198-3208}, doi = {10.1021/acs.jafc.8b05024}, pmid = {30838858}, issn = {1520-5118}, mesh = {Animals ; Biofilms ; Cattle ; Cultured Milk Products/analysis/microbiology ; Fermentation ; Food Microbiology/instrumentation/*methods ; Lactobacillus plantarum/growth & development/metabolism ; Milk/*microbiology ; Nanofibers/chemistry ; Probiotics/*chemistry ; Streptococcus thermophilus/growth & development/metabolism ; }, abstract = {Electrospun nanofiber membranes are widely investigated in the past few decades as candidates for tissue engineering, which can mimic natural extracellular matrix (ECM) and improve cell adhesion, proliferation, and expression on nanofiber membranes. However, the formation of bacterial biofilms on nanofiber membranes and application of the biofilm-integrated nanofiber membranes remain largely unknown. Here, electrospun cellulose acetate nanofiber membranes are first utilized as scaffold materials for Lactobacillus plantarum (L. plantarum) biofilm formation. Nanofiber membranes proved to be an excellent scaffold for bacteria biofilm with high stability, where biofilms were interlocked with nanofibers forming a cohesive structure. In comparison with planktonic bacteria, L. plantarum biofilms on nanofiber membranes show excellent gastrointestinal resistance. Instead of decreasing, the number of viable cells increased after 3 h digestion in vitro. The L. plantarum biofilm-integrated nanofiber membranes were used as reusable starter cultures for fermented milk production showing excellent fermentative ability and higher survival of L. plantarum during shelf life. The viable cells in fermented milk remained at 11 log CFU/g throughout the reusable batches, which is far above the required value of 7 log CFU/g in commercial products. In addition, the produced fermented milk possesses shorter fermentation time and higher survival of probiotics during shelf life. The results suggest electrospun nanofiber membranes are ideal scaffold materials for bacteria biofilms immobilization in biotechnology and fermentation engineering, which broaden the potential use of electrospun nanofiber membranes in microbiology and strengthen the application of biofilms in fermentation engineering.}, } @article {pmid30838598, year = {2019}, author = {Divaris, K and Shungin, D and Rodríguez-Cortés, A and Basta, PV and Roach, J and Cho, H and Wu, D and Ferreira Zandoná, AG and Ginnis, J and Ramamoorthy, S and Kinchen, JM and Kwintkiewicz, J and Butz, N and Ribeiro, AA and Azcarate-Peril, MA}, title = {The Supragingival Biofilm in Early Childhood Caries: Clinical and Laboratory Protocols and Bioinformatics Pipelines Supporting Metagenomics, Metatranscriptomics, and Metabolomics Studies of the Oral Microbiome.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1922}, number = {}, pages = {525-548}, pmid = {30838598}, issn = {1940-6029}, support = {P30 DK034987/DK/NIDDK NIH HHS/United States ; U01 DE025046/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacteria/*genetics/isolation & purification/metabolism ; *Biofilms ; Child, Preschool ; DNA, Bacterial/genetics ; Dental Caries/etiology/*microbiology ; Gene Expression Profiling/methods ; Gingiva/microbiology ; Humans ; Metabolomics/*methods ; Metagenomics/*methods ; Microbiota ; RNA, Bacterial/genetics ; Sequence Analysis, DNA/methods ; Sequence Analysis, RNA/methods ; Software ; Specimen Handling/methods ; Tooth, Deciduous/*microbiology ; Transcriptome ; }, abstract = {Early childhood caries (ECC) is a biofilm-mediated disease. Social, environmental, and behavioral determinants as well as innate susceptibility are major influences on its incidence; however, from a pathogenetic standpoint, the disease is defined and driven by oral dysbiosis. In other words, the disease occurs when the natural equilibrium between the host and its oral microbiome shifts toward states that promote demineralization at the biofilm-tooth surface interface. Thus, a comprehensive understanding of dental caries as a disease requires the characterization of both the composition and the function or metabolic activity of the supragingival biofilm according to well-defined clinical statuses. However, taxonomic and functional information of the supragingival biofilm is rarely available in clinical cohorts, and its collection presents unique challenges among very young children. This paper presents a protocol and pipelines available for the conduct of supragingival biofilm microbiome studies among children in the primary dentition, that has been designed in the context of a large-scale population-based genetic epidemiologic study of ECC. The protocol is being developed for the collection of two supragingival biofilm samples from the maxillary primary dentition, enabling downstream taxonomic (e.g., metagenomics) and functional (e.g., transcriptomics and metabolomics) analyses. The protocol is being implemented in the assembly of a pediatric precision medicine cohort comprising over 6000 participants to date, contributing social, environmental, behavioral, clinical, and biological data informing ECC and other oral health outcomes.}, } @article {pmid30838426, year = {2019}, author = {Khelissa, SO and Abdallah, M and Jama, C and Chihib, NE}, title = {Actively detached Pseudomonas aeruginosa biofilm cell susceptibility to benzalkonium chloride and associated resistance mechanism.}, journal = {Archives of microbiology}, volume = {201}, number = {6}, pages = {747-755}, doi = {10.1007/s00203-019-01643-x}, pmid = {30838426}, issn = {1432-072X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Benzalkonium Compounds/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects ; Drug Resistance, Bacterial ; Plankton/drug effects ; Pseudomonas aeruginosa/*drug effects/physiology ; Stainless Steel/analysis ; Temperature ; }, abstract = {The present work aimed at studying physiological properties of Pseudomonas aeruginosa cells actively detached from biofilm formed on stainless steel and comparing them with their planktonic counterparts as a function of growth temperature (20 °C and 37 °C). The susceptibility of P. aeruginosa cells to benzalkonium chloride (BAC) was studied. Furthermore, the effect of BAC on the cell membrane integrity and the role of the cell membrane fluidity in the cell-scale-resistance mechanism were investigated. Our results showed that actively detached biofilm cells were more susceptible to BAC treatment than planktonic ones. A greater leakage of intracellular potassium after BAC addition was observed in actively detached biofilm cells, which reflects their membrane vulnerability. The rise of the growth temperature from 20 to 37 °C increased the membrane rigidity of planktonic cells comparatively to their actively detached biofilm ones. Under experimental conditions developed in this work, our data highlighted that actively biofilm-detached and planktonic P. aeruginosa cells have distinguishable phenotypes.}, } @article {pmid30837963, year = {2019}, author = {Fonseca, BB and Silva, PLAPA and Silva, ACA and Dantas, NO and de Paula, AT and Olivieri, OCL and Beletti, ME and Rossi, DA and Goulart, LR}, title = {Nanocomposite of Ag-Doped ZnO and AgO Nanocrystals as a Preventive Measure to Control Biofilm Formation in Eggshell and Salmonella spp. Entry Into Eggs.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {217}, pmid = {30837963}, issn = {1664-302X}, abstract = {Salmonella spp. is an important foodborne agent of salmonellosis, whose sources in humans often include products of avian origin. The control of this bacterium is difficult especially when Salmonella spp. is organized into biofilms. We hypothesized that the novel nanocomposites of ZnO nanocrystals doped with silver (Ag) and silver oxide (AgO) nanocrystals (ZnO:Ag-AgO) synthesized by the coprecipitation method could control or prevent the formation of Salmonella Enteritidis (SE) and Salmonella Heidelberg (SH) biofilm and its entry into turkey eggs. The diffraction characteristics of ZnO and AgO showed sizes of 28 and 30 nm, respectively. The Zn to Ag substitution into the ZnO crystalline structure was evidenced by the ionic radius of Ag+2 (1.26 Å), which is greater than Zn+2 (0.74 Å). For the SE analyses post-biofilm formation, the ZnO:Ag-AgO was not able to eliminate the biofilm, but the bacterial load was lower than that of the control group. Additionally, SE was able to infiltrate into the eggs and was found in both albumen and yolk. For the SH analyses applied onto the eggshells before biofilm formation, the ZnO:Ag-AgO treatment prevented biofilm formation, and although the bacterium infiltration into the eggs was observed in all treated groups, it was significantly smaller in ZnO:Ag-AgO pre-treated eggs, and SH could not reach the yolk. There was no difference in pore size between groups; therefore, the inhibition of biofilm formation and the prevention of bacterium entry into the egg were attributable to the use of ZnO:Ag-AgO, which was not influenced by the egg structure. Although the amount of Ag and Zn in the shell of the ZnO:Ag-AgO group was greater in relation to the control, this difference was not detected in the other egg components. In the search for new measures that are effective, safe and viable for controlling microorganisms in poultry farming, the application of a nanocomposite of Ag-doped ZnO and AgO nanocrystals appears as an alternative of great potential to prevent Salmonella sp biofilms in eggshells and other surfaces.}, } @article {pmid30837355, year = {2019}, author = {Ghosh, S and Qureshi, A and Purohit, H}, title = {D-Tryptophan governs biofilm formation rates and bacterial interaction in P. mendocina and S. aureus.}, journal = {Journal of biosciences}, volume = {44}, number = {1}, pages = {}, pmid = {30837355}, issn = {0973-7138}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/*drug therapy/microbiology ; Biofilms/*drug effects/growth & development ; Humans ; Pseudomonas mendocina/drug effects/growth & development/pathogenicity ; Staphylococcus aureus/drug effects/growth & development/pathogenicity ; Tryptophan/*pharmacology ; }, abstract = {Biofilm genesis by Pseudomonasand Staphylococcus sp is associated with biofouling in natural settings. D-Tryptophan (D-Trp) inhibits bacterial biofilms and have been proposed for biofouling control applications. In this study, D-Trp significantly inhibited Pseudomonas mendocina and Staphylococcus aureuscell attachment (biofilm formation) rates on polystyrene96-well microtiter plates in comparison with L-Tryptophan (L-Trp) and mixtures of D-/L-Tryptophan (D-/L-Trp). Theinhibitory effect was greater on P. mendocina,where the rate of cell adherence was declined to 8.79105cells/h from8.09106cells/h (control) inP. mendocina.InS. aureusit was declined to 4.29107cells/h from 9.29107cells/h(control) at 1 mM concentration. It hindered the intracellular communication and adherence in both the strains, as con-firmed by SEM and real time PCR analysis. Addition of D-Trp to preformed biofilms also caused partial disassembly. Intraand interbacterial aggregation were decreased subsequently upon treatment with D-Trp. It repressed the genes involved incell-cell communication, which could be responsible for the diminished biofilm formation of the selected strains. HenceD-Tryptophan has proved to be an effective strategy to control biofilm and may support in the development of surfacecoating technologies.}, } @article {pmid30837338, year = {2019}, author = {Li, F and Cimdins, A and Rohde, M and Jänsch, L and Kaever, V and Nimtz, M and Römling, U}, title = {DncV Synthesizes Cyclic GMP-AMP and Regulates Biofilm Formation and Motility in Escherichia coli ECOR31.}, journal = {mBio}, volume = {10}, number = {2}, pages = {}, pmid = {30837338}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; Culture Media ; Escherichia coli/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Locomotion ; Nucleotides, Cyclic/*biosynthesis ; Nucleotidyltransferases/genetics/*metabolism ; Recombinant Proteins/genetics/metabolism ; Temperature ; Vibrio cholerae/enzymology/genetics ; }, abstract = {Cyclic dinucleotides (cDNs) act as intracellular second messengers, modulating bacterial physiology to regulate the fundamental life style transition between motility and sessility commonly known as biofilm formation. Cyclic GMP-AMP (cGAMP), synthesized by the dinucleotide cyclase DncV, is a newly discovered cDN second messenger involved in virulence and chemotaxis in Vibrio cholerae O1 biovar El Tor. Here we report a novel role for horizontally transferred DncV in cGAMP production and regulation of biofilm formation and motility in the animal commensal strain Escherichia coli ECOR31. ECOR31 expresses a semiconstitutive temperature-independent rdar (red, dry, and rough) morphotype on Congo red agar plates characterized by the extracellular matrix components cellulose and curli fimbriae which requires activation by the major biofilm regulator CsgD and cyclic di-GMP signaling. In contrast, C-terminal His-tagged DncV negatively regulates the rdar biofilm morphotype and cell aggregation via downregulation of csgD mRNA steady-state level. Furthermore, DncV sequentially promotes and inhibits adhesion to the abiotic surface after 24 h and 48 h of growth, respectively. DncV also suppresses swimming and swarming motility posttranscriptional of the class 1 flagellum regulon gene flhD Purified DncV produced different cDNs, cyclic di-GMP, cyclic di-AMP, an unknown product(s), and the dominant species 3'3'-cGAMP. In vivo, only the 3'3'-cGAMP concentration was elevated upon short-term overexpression of dncV, making this work a first report on cGAMP production in E. coli Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in E. coli ECOR31.IMPORTANCE The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the Vibrio cholerae biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal E. coli strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species.}, } @article {pmid30834698, year = {2019}, author = {Nguyen, TV and Minrovic, BM and Melander, RJ and Melander, C}, title = {Identification of Anti-Mycobacterial Biofilm Agents Based on the 2-Aminoimidazole Scaffold.}, journal = {ChemMedChem}, volume = {14}, number = {9}, pages = {927-937}, pmid = {30834698}, issn = {1860-7187}, support = {R01 AI106733/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Antitubercular Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Imidazoles/*chemistry ; Male ; Mice ; Microsomes/drug effects/metabolism ; Mycobacterium tuberculosis/*drug effects ; }, abstract = {Tuberculosis (TB) remains a significant global health problem for which new therapeutic options are sorely needed. The ability of the causative agent, Mycobacterium tuberculosis, to reside within host macrophages and form biofilm-like communities contributes to the persistent and drug-tolerant nature of the disease. Compounds that can prevent or reverse the biofilm-like phenotype have the potential to serve alongside TB antibiotics to overcome this tolerance, and decrease treatment duration. Using Mycobacterium smegmatis as a surrogate organism, we report the identification of two new 2-aminoimidazole compounds that inhibit and disperse mycobacterial biofilms, work synergistically with isoniazid and rifampicin to eradicate preformed M. smegmatis biofilms in vitro, are nontoxic toward Galleria mellonella, and exhibit stability in mouse plasma.}, } @article {pmid30834278, year = {2019}, author = {Bashir, A and Azeem, A and Stedman, Y and Hilton, AC}, title = {Pet Food Factory Isolates of Salmonella Serotypes Do Not Demonstrate Enhanced Biofilm Formation Compared to Serotype-Matched Clinical and Veterinary Isolates.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {8569459}, pmid = {30834278}, issn = {2314-6141}, mesh = {Animal Feed/*microbiology ; Animals ; Biofilms/*growth & development ; Culture Media ; *Food Microbiology ; Humans ; Pets ; Salmonella enterica/*growth & development/pathogenicity ; Serogroup ; Temperature ; }, abstract = {Environmentally persistent Salmonella in the pet food factory environment has been described, with biofilm formation suggested as a candidate mechanism contributing to their persistence. In this study the ability of a panel of Salmonella isolates from factory, clinical, and veterinary sources was investigated for their ability to form biofilms at 24 and 48 hours. The effect of nutrient availability and incubation time on biofilm formation was investigated using full strength and diluted 1/20 TSB media at 37°C, 25°C, 15°C, and 10°C. Results highlighted that all the Salmonella isolates were able to form biofilms in both nutrient conditions and this was highly correlated with temperature. At 25°C, biofilm formation was enhanced in diluted 1/20 TSB and increased incubation time (48h) (p= <0.001). However, this was not observed at 10°C, 15°C, or 37°C. None of the factory isolates demonstrated enhanced biofilm formation in comparison to serotype-matched isolates from veterinary and clinical sources. Salmonella enterica Senftenberg 775W was the strongest biofilm former at 15°C, 25°C, and 37°C in all the conditions tested (p=<0.05). Biofilm formation is an important mechanism of environmental persistence in the food manufacturing environment; however, there is no evidence of an enhanced biofilm-producing phenotype in factory persistent strains.}, } @article {pmid30834226, year = {2019}, author = {Balhaddad, AA and Melo, MAS and Gregory, RL}, title = {Inhibition of nicotine-induced Streptococcus mutans biofilm formation by salts solutions intended for mouthrinses.}, journal = {Restorative dentistry & endodontics}, volume = {44}, number = {1}, pages = {e4}, pmid = {30834226}, issn = {2234-7658}, abstract = {OBJECTIVES: Biofilm formation is critical to dental caries initiation and development. The aim of this study was to investigate the effects of nicotine exposure on Streptococcus mutans (S. mutans) biofilm formation concomitantly with the inhibitory effects of sodium chloride (NaCl), potassium chloride (KCl) and potassium iodide (KI) salts. This study examined bacterial growth with varying concentrations of NaCl, KCl, and KI salts and nicotine levels consistent with primary levels of nicotine exposure.

MATERIALS AND METHODS: A preliminary screening experiment was performed to investigate the appropriate concentrations of NaCl, KCl, and KI to use with nicotine. With the data, a S. mutans biofilm growth assay was conducted using nicotine (0-32 mg/mL) in Tryptic Soy broth supplemented with 1% sucrose with and without 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI. The biofilm was stained with crystal violet dye and the absorbance measured to determine biofilm formation.

RESULTS: The presence of 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI significantly inhibited (p < 0.05) nicotine-induced S. mutans biofilm formation by 52%, 79.7%, and 64.1%, respectively.

CONCLUSIONS: The results provide additional evidence regarding the biofilm-enhancing effects of nicotine and demonstrate the inhibitory influence of these salts in reducing the nicotine-induced biofilm formation. A short-term exposure to these salts may inhibit S. mutans biofilm formation.}, } @article {pmid30833815, year = {2019}, author = {Courrol, DDS and Lopes, CRB and Pereira, CBP and Franzolin, MR and Silva, FRO and Courrol, LC}, title = {Tryptophan Silver Nanoparticles Synthesized by Photoreduction Method: Characterization and Determination of Bactericidal and Anti-Biofilm Activities on Resistant and Susceptible Bacteria.}, journal = {International journal of tryptophan research : IJTR}, volume = {12}, number = {}, pages = {1178646919831677}, pmid = {30833815}, issn = {1178-6469}, abstract = {The high rates of antibiotics use in hospitals have resulted in a condition where multidrug-resistant pathogens have become a severe threat to the human health worldwide. Therefore, there is an increasing necessity to identify new antimicrobial agents that can inhibit the multidrug-resistant bacteria and biofilm formation. In this study, antibacterial and anti-biofilm activities of tryptophan silver nanoparticles (TrpAgNP) were investigated. The TrpAgNPs were synthesized by photoreduction method, and the influence of irradiation time and concentration of reagents were analyzed. The nanoparticles were characterized by transmission electron microscopy, Zeta Potential and (UV)-absorption spectra. The antibacterial activity of TrpAgNPs was tested for antibiotic-resistant and susceptible pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Salmonella typhimurium, and Pseudomonas aeruginosa, evaluating the influence of photoreduction parameters in bactericidal effect. The results have shown that TrpAgNPs solutions with lower tryptophan/silver nitrate (AgNO3) ratio and higher AgNO3 concentration have higher bactericidal action against bacteria with inhibition of ~100% in almost all studied bacterial strains. The antimicrobial activity of TrpAgNPs within biofilms generated under static conditions of antibiotic-resistant and susceptible strains of S. aureus, S. epidermidis, E. coli, K. pneumoniae, C. freundii, and P. aeruginosa was also investigated. The results showed that TrpAgNPs have an inhibitory effect against biofilm formation, exceeding 50% in the case of Gram-negative bacteria (E. coli, K. pneumoniae, C. freundii, and P. aeruginosa-54.8% to 98.8%). For Gram-positive species, an inhibition of biofilm formation of 68.7% to 72.2 % was observed for S. aureus and 20.0% to 40.2% for S. epidermidis.}, } @article {pmid30833358, year = {2019}, author = {Mihajlovic, J and Bechon, N and Ivanova, C and Chain, F and Almeida, A and Langella, P and Beloin, C and Ghigo, JM}, title = {A Putative Type V Pilus Contributes to Bacteroides thetaiotaomicron Biofilm Formation Capacity.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {30833358}, issn = {1098-5530}, mesh = {Animals ; Bacterial Adhesion/physiology ; Bacteroides thetaiotaomicron/*physiology ; Biofilms/*growth & development ; Fimbriae, Bacterial/*physiology ; Gastrointestinal Microbiome/physiology ; Humans ; Male ; Mice ; Mice, Inbred C3H ; }, abstract = {Bacteroides thetaiotaomicron is a prominent anaerobic member of the healthy human gut microbiota. While the majority of functional studies on B. thetaiotaomicron addressed its impact on the immune system and the utilization of diet polysaccharides, B. thetaiotaomicron biofilm capacity and its contribution to intestinal colonization are still poorly characterized. We tested the natural adhesion of 34 B. thetaiotaomicron isolates and showed that although biofilm capacity is widespread among B. thetaiotaomicron strains, this phenotype is masked or repressed in the widely used reference strain VPI 5482. Using transposon mutagenesis followed by a biofilm positive-selection procedure, we identified VPI 5482 mutants with increased biofilm capacity corresponding to an alteration in the C-terminal region of BT3147, encoded by the BT3148-BT3147 locus, which displays homology with Mfa-like type V pili found in many Bacteroidetes We show that BT3147 is exposed on the B. thetaiotaomicron surface and that BT3147-dependent adhesion also requires BT3148, suggesting that BT3148 and BT3147 correspond to the anchor and stalk subunits of a new type V pilus involved in B. thetaiotaomicron adhesion. This study therefore introduces B. thetaiotaomicron as a model to study proteinaceous adhesins and biofilm-related phenotypes in this important intestinal symbiont.IMPORTANCE Although the gut anaerobe Bacteroides thetaiotaomicron is a prominent member of the healthy human gut microbiota, little is known about its capacity to adhere to surfaces and form biofilms. Here, we identify that alteration of a surface-exposed protein corresponding to a type of pili found in many Bacteroidetes increases B. thetaiotaomicron biofilm formation. This study lays the ground for establishing this bacterium as a model organism for in vitro and in vivo studies of biofilm-related phenotypes in gut anaerobes.}, } @article {pmid30833350, year = {2019}, author = {Yannarell, SM and Grandchamp, GM and Chen, SY and Daniels, KE and Shank, EA}, title = {A Dual-Species Biofilm with Emergent Mechanical and Protective Properties.}, journal = {Journal of bacteriology}, volume = {201}, number = {18}, pages = {}, pmid = {30833350}, issn = {1098-5530}, support = {R01 GM112981/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacillus subtilis/metabolism ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Extracellular Matrix/metabolism/physiology ; Pantoea/metabolism ; }, abstract = {Many microbes coexist within biofilms, or multispecies communities of cells encased in an extracellular matrix. However, little is known about the microbe-microbe interactions relevant for creating these structures. In this study, we explored a striking dual-species biofilm between Bacillus subtilis and Pantoea agglomerans that exhibited characteristics that were not predictable from previous work examining monoculture biofilms. Coculture wrinkle formation required a P. agglomerans exopolysaccharide as well as the B. subtilis amyloid-like protein TasA. Unexpectedly, other B. subtilis matrix components essential for monoculture biofilm formation were not necessary for coculture wrinkling (e.g., the exopolysaccharide EPS, the hydrophobin BslA, and cell chaining). In addition, B. subtilis cell chaining prevented coculture wrinkling, even though chaining was previously associated with more robust monoculture biofilms. We also observed that increasing the relative proportion of P. agglomerans (which forms completely featureless monoculture colonies) increased coculture wrinkling. Using microscopy and rheology, we observed that these two bacteria assemble into an organized layered structure that reflects the physical properties of both monocultures. This partitioning into distinct regions negatively affected the survival of P. agglomerans while also serving as a protective mechanism in the presence of antibiotic stress. Taken together, these data indicate that studying cocultures is a productive avenue to identify novel mechanisms that drive the formation of structured microbial communities.IMPORTANCE In the environment, many microbes form biofilms. However, the interspecies interactions underlying bacterial coexistence within these biofilms remain understudied. Here, we mimic environmentally relevant biofilms by studying a dual-species biofilm formed between Bacillus subtilis and Pantoea agglomerans and subjecting the coculture to chemical and physical stressors that it may experience in the natural world. We determined that both bacteria contribute structural elements to the coculture, which is reflected in its overall viscoelastic behavior. Existence within the coculture can be either beneficial or detrimental depending on the context. Many of the features and determinants of the coculture biofilm appear distinct from those identified in monoculture biofilm studies, highlighting the importance of characterizing multispecies consortia to understand naturally occurring bacterial interactions.}, } @article {pmid30833012, year = {2019}, author = {Kusuma Yulianto, HD and Rinastiti, M and Cune, MS and de Haan-Visser, W and Atema-Smit, J and Busscher, HJ and van der Mei, HC}, title = {Biofilm composition and composite degradation during intra-oral wear.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {5}, pages = {740-750}, doi = {10.1016/j.dental.2019.02.024}, pmid = {30833012}, issn = {1879-0097}, mesh = {Biofilms ; Bisphenol A-Glycidyl Methacrylate ; *Composite Resins ; Humans ; Materials Testing ; *Streptococcus mutans ; Surface Properties ; }, abstract = {OBJECTIVES: The oral environment limits the longevity of composite-restorations due to degradation caused by chewing, salivary and biofilm-produced enzymes and acids. This study investigates degradation of two resin-composites in relation with biofilm composition in vitro and in vivo.

METHODS: Surface-chemical-composition of two Bis-GMA/TEGDMA composites was compared using X-ray-Photoelectron-Spectroscopy from which the number ester-linkages was derived. Composite-degradation was assessed through water contact angles, yielding surface-exposure of filler-particles. Degradation in vitro was achieved by composite immersion in a lipase solution. In order to evaluate in vivo degradation, composite samples were worn in palatal devices by 15 volunteers for 30-days periods in absence and presence of manually-brushing with water. PCR-DGGE analysis was applied to determine biofilm composition on the samples, while in addition to water contact angles, degradation of worn composites was assessed through surface-roughness and micro-hardness measurements.

RESULTS: In vitro degradation by lipase exposure was highest for the high ester-linkage composite and virtually absent for the low ester-linkage composite. Filler-particle surface-exposure, surface-roughness and micro-hardness of both resin-composites increased during intra-oral wear, but filler-particle surface-exposure was affected most. However, based on increased filler-particle surface-exposure, the high ester-linkage composite degraded most in volunteers harvesting composite biofilms comprising Streptococcus mutans, a known esterase and lactic acid producer. This occurred especially in absence of brushing.

SIGNIFICANCE: Degradation during intra-oral wear of a low ester-linkage composite was smaller than of a high ester-linkage composite, amongst possible other differences between both composites. S. mutans herewith is not only a cariogenic, but also a composite-degradative member of the oral microbiome.}, } @article {pmid30832841, year = {2019}, author = {Ashrafi, B and Rashidipour, M and Marzban, A and Soroush, S and Azadpour, M and Delfani, S and Ramak, P}, title = {Mentha piperita essential oils loaded in a chitosan nanogel with inhibitory effect on biofilm formation against S. mutans on the dental surface.}, journal = {Carbohydrate polymers}, volume = {212}, number = {}, pages = {142-149}, doi = {10.1016/j.carbpol.2019.02.018}, pmid = {30832841}, issn = {1879-1344}, mesh = {Biofilms/*drug effects/growth & development ; Chitosan/*administration & dosage/metabolism ; Dental Caries/drug therapy/microbiology ; Dental Plaque/drug therapy/microbiology ; Humans ; Mentha piperita ; Nanogels ; Plant Oils/*administration & dosage/isolation & purification/metabolism ; Polyethylene Glycols/*administration & dosage/metabolism ; Polyethyleneimine/*administration & dosage/metabolism ; Streptococcus mutans/*drug effects/growth & development ; Tooth/*drug effects/microbiology ; }, abstract = {Mentha piperita essential oils (MPEO) were loaded into chitosan nanogel to use as antibiofilm agent against Streptococcus mutans and to protect its dental plaque. Chitosan nanoparticles (CsNPs) were prepared by sol-gel method using linking bridge of tripolyphosphate (TPP). Physiological properties of MPEO-CNs were assessed by FTIR, SEM/EDX, DLS and zeta potential. Release kinetics, MIC and MBC were determined for MPEO-CNs. Expression of biofilm-associated genes including 8 genes: grfB, C and D, brpA, spaP, gbpB, relA and vicR was investigated at the presence of sub-MIC of MPEO-CNs. Most abundant bioactive compounds of MPEO were l-menthol (45.05%) and l-menthal (17.53%). SEM/EDX exhibited successful entrapment of MPEO into CsNPs followed by the changes in abundance of elemental peaks. A signal at 1737 cm[-1] on chitosan spectrum was attributed to the carboxylic (CO) groups overlapped by MPEO incorporation. A new signal at 2361 cm[-1] was assigned to electrostatic interactions of amine groups in chitosan with phosphoric units of TPP within the MPEO-chitosan. MPEO incorporation into porous nanogel decreased monodispersity of the nanoparticles and then raises z-average. Maximum release of MPEO was about 50% during 360 h in a hydroalcoholic solvent at ambient temperature. The adherence of bacterial cells showed high sensitivity to the nanoformulation of MPEO compared with unloaded chitosan-nanogel. Antibiofilm inhibition of S. mutans occurred in 50 and 400 μg/mL for MPEO-CNs and unloaded-nanogel, respectively. Among biofilm synthesis genes, gtfB, gtfC, gtfD were slightly affected by MPEO-CNs treatment, while gbpB, spaP, brpA, relA, and vicR genes underwent significant down-regulation in the presence of both unloaded-nanogel and MPEO-loaded-nanogel. This study demonstrated that the MPEO-CNs promised an efficient nanoformulation with the greatest inhibitory action against some glycosyltransferase genes (gtfB, C and D) as important enzymes involved in extracellular polymers. Finally, the results concluded that MPEO-CNs have a potential use as antibiofilm agent in toothpaste or mouth washing formulations.}, } @article {pmid30831512, year = {2019}, author = {Sonwani, RK and Swain, G and Giri, BS and Singh, RS and Rai, BN}, title = {A novel comparative study of modified carriers in moving bed biofilm reactor for the treatment of wastewater: Process optimization and kinetic study.}, journal = {Bioresource technology}, volume = {281}, number = {}, pages = {335-342}, doi = {10.1016/j.biortech.2019.02.121}, pmid = {30831512}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Kinetics ; Polyethylene/chemistry ; Polypropylenes/chemistry ; Polyurethanes/chemistry ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater/*chemistry ; }, abstract = {In this work, modified plastic carriers; polypropylene (PP), low-density polyethylene- polypropylene (LDPE-PP), and polyurethane foam-polypropylene (PUF-PP) were developed and used in moving bed bioreactor (MBBR) for the wastewater treatment containing naphthalene. To optimized the process parameters using response surface methodology (RSM), two numerical variables; pH (5.0-9.0) and hydraulic retention time (HRT) (1.0-5.0 day) along with the type of carriers (PP, LDPE-PP, and PUF-PP) were selected as a categorical factor. At 7.0 pH and 5 days HRT, maximum removal efficiencies were observed to be 72.4, 84.4, and 90.2% for MBBR packed with PP, LDPE-PP, and PUF-PP carriers, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis reveals catechol and 2-naphthol were observed as intermediate metabolites for naphthalene degradation. Modified Stover-Kincannon model was applied for biodegradation kinetic and constants were observed as Umax: 0.476, 0.666, and 0.769 g/L.day and KB: 0.565, 0.755, and 0.874 g/L.day for PP, LDPE-PP, PUF-PP, respectively.}, } @article {pmid30831511, year = {2019}, author = {Gao, JF and Liu, XH and Fan, XY and Dai, HH}, title = {Effects of triclosan on performance, microbial community and antibiotic resistance genes during partial denitrification in a sequencing moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {281}, number = {}, pages = {326-334}, doi = {10.1016/j.biortech.2019.02.112}, pmid = {30831511}, issn = {1873-2976}, mesh = {Biofilms/*drug effects ; Denitrification/drug effects ; *Drug Resistance, Microbial/genetics ; Microbiota/*drug effects ; Nitrites/metabolism ; Sewage ; Triclosan/*pharmacology ; }, abstract = {Effects of triclosan (TCS) on performance, microbial community and antibiotic resistance genes (ARGs) during partial denitrification (PD) were investigated in a sequencing moving bed biofilm reactor (SMBBR). TCS inhibited nitrite accumulation; inhibition effect was more obvious as TCS concentration increased from 1 to 5 mg/L, but it could recover. Extracellular polymeric substances contents increased with 1 mg/L TCS addition and decreased a lot at 5 mg/L TCS. Community structure in biofilm was different from that in floccular sludge, but it was similar at 5 mg/L TCS. Illumina sequencing showed that Pseudomonas, Aeromonas, Shewanella and Thauera became dominant genera. Abundance of nirS was stable and higher than that of narG and nosZ. High-throughput qPCR showed that mexF, acrA-02, fabK, etc. were screened at 5 mg/L TCS. IntI1 and tnpA-04 were abundant mobile genetic elements. The study furthers understanding of effects of TCS on PD, bacterial communities and ARGs in SMBBR.}, } @article {pmid30831372, year = {2019}, author = {Cui, X and Chen, C and Liu, Y and Zhou, D and Liu, M}, title = {Exogenous refractory protein enhances biofilm formation by altering the quorum sensing system: A potential hazard of soluble microbial proteins from WWTP effluent.}, journal = {The Science of the total environment}, volume = {667}, number = {}, pages = {384-389}, doi = {10.1016/j.scitotenv.2019.02.370}, pmid = {30831372}, issn = {1879-1026}, mesh = {Bacteria ; Bacterial Proteins/*analysis ; Biofilms ; Gene Expression Regulation, Bacterial ; *Quorum Sensing ; Waste Disposal, Fluid/*methods ; Wastewater/*microbiology ; Water Pollutants/*analysis ; }, abstract = {Soluble microbial refractory proteins are major components of effluent from wastewater treatment plants that utilize a biological wastewater treatment process. The remaining proteins could negatively affect downstream treatment processes by altering the bacterial quorum sensing system. In this work, we elaborated the effects of exogenous refractory protein on biofilm formation. The results showed a linear relationship between biofilm formation and experimental protein concentrations at the range typically found in effluent, 0-8.0 mg/L. Micro-observation revealed that the exogenous refractory protein stimulated extracellular polysaccharide secretion to promote biofilm maturation. Extracellular polysaccharides increased by ~200% with the addition of only 2.0 mg/L protein. In addition, exogenous refractory proteins altered the quorum sensing system gene expression and polysaccharide gene expression. This work found that exogenous protein accelerated biofilm formation by influencing the quorum sensing system, thus providing new insight into the potential harm of soluble microbial refractory products.}, } @article {pmid30831325, year = {2019}, author = {Rodríguez López, AL and Lee, MR and Ortiz, BJ and Gastfriend, BD and Whitehead, R and Lynn, DM and Palecek, SP}, title = {Preventing S. aureus biofilm formation on titanium surfaces by the release of antimicrobial β-peptides from polyelectrolyte multilayers.}, journal = {Acta biomaterialia}, volume = {93}, number = {}, pages = {50-62}, pmid = {30831325}, issn = {1878-7568}, support = {P41 RR002301/RR/NCRR NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; R21 AI127442/AI/NIAID NIH HHS/United States ; T32 GM008349/GM/NIGMS NIH HHS/United States ; R01 AI092225/AI/NIAID NIH HHS/United States ; R33 AI127442/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Antimicrobial Cationic Peptides/chemistry/pharmacokinetics/pharmacology ; Biofilms/*drug effects ; Cell Line ; *Coated Materials, Biocompatible/chemistry/pharmacokinetics/pharmacology ; Mice ; Prosthesis-Related Infections/*drug therapy/microbiology ; Staphylococcus aureus/*physiology ; Surface Properties ; *Titanium/chemistry/pharmacokinetics/pharmacology ; }, abstract = {Staphylococcus aureus infections represent the major cause of titanium based-orthopaedic implant failure. Current treatments for S. aureus infections involve the systemic delivery of antibiotics and additional surgeries, increasing health-care costs and affecting patient's quality of life. As a step toward the development of new strategies that can prevent these infections, we build upon previous work demonstrating that the colonization of catheters by the fungal pathogen Candida albicans can be prevented by coating them with thin polymer multilayers composed of chitosan (CH) and hyaluronic acid (HA) designed to release a β-amino acid-based peptidomimetic of antimicrobial peptides (AMPs). We demonstrate here that this β-peptide is also potent against S. aureus (MBPC = 4 μg/mL) and characterize its selectivity toward S. aureus biofilms. We demonstrate further that β-peptide-containing CH/HA thin-films can be fabricated on the surfaces of rough planar titanium substrates in ways that allow mammalian cell attachment and permit the long-term release of β-peptide. β-Peptide loading on CH/HA thin-films was then adjusted to achieve release of β-peptide quantities that selectively prevent S. aureus biofilms on titanium substrates in vitro for up to 24 days and remained antimicrobial after being challenged sequentially five times with S. aureus inocula, while causing no significant MC3T3-E1 preosteoblast cytotoxicity compared to uncoated and film-coated controls lacking β-peptide. We conclude that these β-peptide-containing films offer a novel and promising localized delivery approach for preventing orthopaedic implant infections. The facile fabrication and loading of β-peptide-containing films reported here provides opportunities for coating other medical devices prone to biofilm-associated infections. STATEMENT OF SIGNIFICANCE: Titanium (Ti) and its alloys are used widely in orthopaedic devices due to their mechanical strength and long-term biocompatibility. However, these devices are susceptible to bacterial colonization and the subsequent formation of biofilms. Here we report a chitosan and hyaluronic acid polyelectrolyte multilayer-based approach for the localized delivery of helical, cationic, globally amphiphilic β-peptide mimetics of antimicrobial peptides to inhibit S. aureus colonization and biofilm formation. Our results reveal that controlled release of this β-peptide can selectively kill S. aureus cells without exhibiting toxicity toward MC3T3-E1 preosteoblast cells. Further development of this polymer-based coating could result in new strategies for preventing orthopaedic implant-related infections, improving outcomes of these titanium implants.}, } @article {pmid30831229, year = {2019}, author = {Hiller, CC and Lucca, V and Carvalho, D and Borsoi, A and Borges, KA and Furian, TQ and do Nascimento, VP}, title = {Influence of catecholamines on biofilm formation by Salmonella Enteritidis.}, journal = {Microbial pathogenesis}, volume = {130}, number = {}, pages = {54-58}, doi = {10.1016/j.micpath.2019.02.032}, pmid = {30831229}, issn = {1096-1208}, mesh = {Biofilms/*drug effects/*growth & development ; Catecholamines/*metabolism ; Epinephrine/metabolism ; Gene Expression Profiling ; Norepinephrine/metabolism ; Polymerase Chain Reaction ; Quorum Sensing/drug effects ; Salmonella enteritidis/*drug effects/*growth & development ; Temperature ; Virulence Factors/biosynthesis/genetics ; }, abstract = {Salmonella spp. are the main pathogens responsible for foodborne disease worldwide. Bacterial communities use the quorum sensing system to control biofilm formation. These systems function through the secretion of substances, called auto-inducers (AI), into the environment. AI-3 is structurally similar to epinephrine (EPI) and norepinephrine (NOR) -catecholamines secreted by eukaryotic cells to communicate with each other. In this context, this work aimed to evaluate the effect of EPI and NOR on biofilm formation by S. Enteritidis at 12 °C and 25 °C. Also, we detected the presence of the csgD, adrA, and fimA genes in these strains. Biofilm formation was investigated at two temperatures (12 °C and 25 °C) using a microtiter plate assay, under four different treatments (50 mM EPI, 100 mM EPI, 50 mM NOR; 100 mM NOR) and a control group. PCR was used to detect the virulence genes associated with biofilm production. A greater number of biofilm producer isolates were observed at 25 °C than at 12 °C, regardless of the treatment. The number of biofilms forming strains at 12 °C was significantly higher in the treatment with norepinephrine at 100 μM. The proportion of non-producer and biofilm producer strains at 25 °C did not differ significantly among the treatments. All strains presented the three genes (csgD, adrA, and fimA). The approach carried out in this work is a precursor in veterinary medicine, focusing on both public and poultry health, and evaluates the influence of catecholamines on the formation of biofilms with S. Enteritidis, an important pathogen with zoonotic potential. Norepinephrine seems to be more efficient at stimulating biofilm formation by S. Enteritidis strains at 12 °C. csgD, fimA, and adrA were detected in all strains.}, } @article {pmid30830100, year = {2019}, author = {Maev, IV and Bazikyan, EA and Lukina, GI and Zayratyants, OV and Chunikhin, AA}, title = {[Features of filiform papillary lesion of the tongue and its mucosal microflora biofilm in patients with gastroesophageal reflux disease].}, journal = {Arkhiv patologii}, volume = {81}, number = {1}, pages = {18-23}, doi = {10.17116/patol20198101118}, pmid = {30830100}, issn = {0004-1955}, mesh = {*Biofilms ; Epithelium ; *Gastroesophageal Reflux/complications ; Humans ; Microscopy, Electron, Scanning ; *Tongue/microbiology/pathology ; }, abstract = {OBJECTIVE: To identify filiform papillary lesions, localization changes, and the composition of the microflora of the dorsal lingual surface in patients with gastroesophageal reflux disease (GERD).

MATERIAL AND METHODS: Dorsal lingual surface biopsy specimens were investigated in 7 patients with GERD (3 men, 4 women) and in 6 individuals without digestive diseases (3 men, 3 women). The diagnosis of GERD was based on a set of clinical data, daily pH-metry, EGDS, and the specialized GerdQ questionnaire. Scanning electron microscopy and fluorescence confocal microscopy were used.

RESULTS: Intact filiform lingual papillae had a complex structure and consisted of primary and secondary papillae. Foci of increased epithelial desquamation with partial or complete loss of secondary papillae were detected in patients with GERD. There was a microflora biofilm only on the epithelium of the secondary papillae in the intact areas and in the areas with preserved secondary papillae in patients with GERD. On the contrary, the foci of lesion and those with completely lost secondary papillae in GERD patients exhibited the microflora (more diverse in its morphological characteristics) on the surface of the epithelial cells of primary papillae, except for their cup-shaped hollows in the area of the lost secondary processes. These cup-shaped hollows preserved dense intercellular contacts of epithelial cells.

CONCLUSION: The lingual mucosal filiform papillae in GERD patients are characterized by the appearance of areas with partial or complete loss of secondary papillae and with increased desquamation of epithelial cells. There is microflora biofilm translocation to the primary papillae, except for their cup-shaped hollows (an area of the lost secondary papillae). Translocation of the microflora increased its morphological diversity.}, } @article {pmid30828488, year = {2019}, author = {Shang, F and Li, L and Yu, L and Ni, J and Chen, X and Xue, T}, title = {Effects of stigmata maydis on the methicillin resistant Staphylococus aureus biofilm formation.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6461}, pmid = {30828488}, issn = {2167-8359}, abstract = {BACKGROUND: Mastitis is an inflammatory reaction of the mammary gland tissue, which causes huge losses to dairy farms throughout the world. Staphylococcus aureus is the most frequent agent associated with this disease. Staphylococcus aureus isolates, which have the ability to form biofilms, usually lead to chronic mastitis in dairy cows. Moreover, methicillin resistance of the bacteria further complicates the treatment of this disease. Stigmata maydis (corn silk), a traditional Chinese medicine, possess many biological activities.

METHODS: In this study, we performed antibacterial activity assays, biofilm formation assays and real-time reverse transcription PCR experiments to investigate the effect of stigmata maydis (corn silk) on biofilm formation and vancomycin susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from dairy cows with mastitis.

RESULTS: In this study, the aqueous extracts of stigmata maydis inhibited the biofilm formation ability of MRSA strains and increased the vancomycin susceptibility of the strains under biofilm-cultured conditions.

CONCLUSION: This study proves that the aqueous extracts of stigmata maydis inhibit the biofilm formation ability of MRSA strains and increase the vancomycin susceptibility of the MRSA strains under biofilm-cultured conditions.}, } @article {pmid30827805, year = {2019}, author = {Beganovic, M and Luther, MK and Daffinee, KE and LaPlante, KL}, title = {Biofilm prevention concentrations (BPC) of minocycline compared to polymyxin B, meropenem, and amikacin against Acinetobacter baumannii.}, journal = {Diagnostic microbiology and infectious disease}, volume = {94}, number = {3}, pages = {223-226}, doi = {10.1016/j.diagmicrobio.2019.01.016}, pmid = {30827805}, issn = {1879-0070}, mesh = {Acinetobacter baumannii/*drug effects/growth & development ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Humans ; Minocycline/*pharmacology ; }, abstract = {Infections caused by Acinetobacter baumannii are difficult to treat as they are often multidrug resistant (MDR) and frequently form biofilms. We investigated the activities of minocycline, polymyxin B, meropenem, and amikacin against diverse Acinetobacter baumannii strains with biofilm formation classified as weak versus moderate/strong. At clinically achievable concentrations, minocycline prevented biofilm formation for 96% of isolates versus 54% for polymyxin B, 29% for meropenem and 29% for amikacin. Minocycline and polymyxin B demonstrated highest in vitro activity against A. baumannii and prevented biofilm formation for a majority of isolates.}, } @article {pmid30826880, year = {2019}, author = {Hamilos, DL}, title = {Biofilm Formations in Pediatric Respiratory Tract Infection Part 2: Mucosal Biofilm Formation by Respiratory Pathogens and Current and Future Therapeutic Strategies to Inhibit Biofilm Formation or Eradicate Established Biofilm.}, journal = {Current infectious disease reports}, volume = {21}, number = {2}, pages = {8}, pmid = {30826880}, issn = {1523-3847}, abstract = {PURPOSE OF REVIEW: The purpose of this review is to discuss the unique pathways of biofilm formation utilized by respiratory pathogens and current and future therapeutic strategies to inhibit biofilm formation or eradicate established biofilm in the context of these pathogens. Both nonselective and selective strategies for inhibiting biofilm formation or disrupting established biofilm are discussed.

RECENT FINDINGS: Numerous strategies are being actively pursued to inhibit biofilm formation or eradicate established biofilm in respiratory pathogens. These can be broadly categorized by the stage of biofilm formation (adhesion, extracellular polysaccharide synthesis or structure, EPS, and matrix degradation) that they target and by their selectivity or lack thereof for specific biofilm pathogens. Nonselective inhibitors of adhesion include N-acetylcysteine and artificial surfactants and biosurfactants. Selective inhibitors of adhesion include mannosides that target host-EPS interactions, EPS-targeted antibodies, and other inhibitors of bacterial adhesion. Nonselective inhibitors of EPS synthesis and structure include cyclic di-GMP and cyclic di-AMP-through disruption of glucan-producing exoenzymes. Selective inhibitors of EPS synthesis and structure include antibodies that target proteins essential for biofilm structure (such as DNABII proteins and type IV pilin protein in NTHi) or antibodies that target critical molecules in biofilm formation (such as DNA adenine methyltransferase in Streptococcus pneumoniae). Nonselective agents for EPS or biofilm matrix degradation include peptidoglycan hydrolases that enzymatically degrade bacterial cell wall peptidoglycan and DNase, which degrades extracellular DNA from neutrophils and microorganism-derived DNA. Selective agents for EPS or biofilm matrix degradation include exopolysaccharide-degrading enzymes, such as glycoside hydrolases active against Staphylococcus aureus or exopolysaccharide-degrading enzymes that target Psl and Pel from Pseudomonas aeruginosa. Current strategies toward inhibiting biofilm formation or disrupting established biofilm represent an exciting new approach toward treatment of chronic infectious diseases. Application of these strategies toward treatment of pediatric respiratory tract infections also offers promise of a better understanding of the significance of mucosal biofilm in the pathogenesis of these conditions.}, } @article {pmid30826631, year = {2019}, author = {Perez, AP and Perez, N and Lozano, CMS and Altube, MJ and de Farias, MA and Portugal, RV and Buzzola, F and Morilla, MJ and Romero, EL}, title = {The anti MRSA biofilm activity of Thymus vulgaris essential oil in nanovesicles.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {57}, number = {}, pages = {339-351}, doi = {10.1016/j.phymed.2018.12.025}, pmid = {30826631}, issn = {1618-095X}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Halorubrum/chemistry ; Humans ; Macrophages/drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Mice ; Microbial Sensitivity Tests ; Nanostructures/chemistry ; Oils, Volatile/chemistry/*pharmacology ; Phosphatidylcholines/chemistry ; Polysorbates/chemistry ; Staphylococcal Infections/microbiology ; Thymus Plant/*chemistry ; }, abstract = {BACKGROUND: Thymus vulgaris essential oil (T) could be an alternative to classical antibiotics against bacterial biofilms, which show increased tolerance to antibiotics and host defence systems and contribute to the persistence of chronic bacterial infections.

HYPOTHESIS: A nanovesicular formulation of T may chemically protect the structure and relative composition of its multiple components, potentially improving its antibacterial and antibiofilm activity.

STUDY DESIGN: We prepared and structurally characterized T in two types of nanovesicles: nanoliposomes (L80-T) made of Soybean phosphatidylcholine (SPC) and Polysorbate 80 (P80) [SPC:P80:T 1:0.75:0.3 w:w], and nanoarchaeosomes (A80-T) made of SPC, P80 and total polar archaeolipids (TPA) extracted from archaebacteria Halorubrum tebenquichense [SPC:TPA:P80:T 0.5:0.50.75:0.7 w:w]. We determined the macrophage cytotoxicity and the antibacterial activity against Staphylococcus aureus ATCC 25,923 and four MRSA clinical strains.

RESULTS: L80-T (Z potential -4.1 ± 0.6 mV, ∼ 115 nm, ∼ 22 mg/ml T) and A80-T (Z potential -6.6 ± 1.5 mV, ∼ 130 nm, ∼ 42 mg/ml T) were colloidally and chemically stable, maintaining size, PDI, Z potential and T concentration for at least 90 days. While MIC90 of L80-T was > 4 mg/ml T, MIC90 of A80-T was 2 mg/ml T for all S. aureus strains. The antibiofilm formation activity was maximal for A80-T, while L80-T did not inhibit biofilm formation compared to untreated control. A80-T significantly decreased the biomass of preformed biofilms of S. aureus ATCC 25,923 strain and of 3 of the 4 clinical MRSA isolates at 4 mg/ml T. It was found that the viability of J774A.1 macrophages was decreased significantly upon 24 h incubation with A80-T, L80-T and T emulsion at 0.4 mg/ml T. These results show that from 0.4 mg/ml T, a value lower than MIC90 and the one displaying antibiofilm activity, with independence of its formulation, T significantly decreased the macrophages viability.

CONCLUSION: Overall, because of its lower MIC90 against planktonic bacteria, higher antibiofilm formation capacity and stability during storage, A80-T resulted better antibacterial agent than T emulsion and L80-T. These results open new avenues to explode the A80-T antimicrobial intracellular activity.}, } @article {pmid30826440, year = {2019}, author = {Rajamani, S and Sandy, R and Kota, K and Lundh, L and Gomba, G and Recabo, K and Duplantier, A and Panchal, RG}, title = {Robust biofilm assay for quantification and high throughput screening applications.}, journal = {Journal of microbiological methods}, volume = {159}, number = {}, pages = {179-185}, doi = {10.1016/j.mimet.2019.02.018}, pmid = {30826440}, issn = {1872-8359}, mesh = {Acinetobacter baumannii/*drug effects/physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Evaluation, Preclinical/*methods ; High-Throughput Screening Assays/*methods ; }, abstract = {Bacterial biofilms are populations of bacteria within a self-produced adherent extracellular matrix that are notoriously resistant to treatment. Existing methods for biofilm quantification are often limited in their dynamic range of detection (signal-to-background), throughput, and require modifications to the protocol depending on the bacterial species. To address these limitations, a broad utility, high-throughput (HTP) method was required. Using a fluorescent dye, FM1-43, we stained the biofilm, followed by solvent extraction and quantitation of biofilm employing a fluorescent plate reader. Utilizing eight different bacterial pathogens, we demonstrate that this method is widely applicable for biofilm quantification. Depending on the species, this biofilm assay offered a large dynamic range of 8-146 fold change compared to 2-22 fold for crystal violet staining under similar conditions. In addition to routine biofilm quantification using this new assay, as a proof-of-concept, 1200 compounds were screened against two different bacterial species to identify biofilm inhibitors. In our HTP screens we successfully identified compounds rifabutin and ethavarine as potential biofilm inhibitors of Burkholderia pseudomallei Bp82 and Acinetobacter baumannii biofilm production respectively. This newly validated biofilm assay is robust and can be readily adapted for antibiofilm screening campaigns and can supplant other less sensitive and low throughput methods.}, } @article {pmid30825823, year = {2019}, author = {Lv, PL and Shi, LD and Wang, Z and Rittmann, B and Zhao, HP}, title = {Methane oxidation coupled to perchlorate reduction in a membrane biofilm batch reactor.}, journal = {The Science of the total environment}, volume = {667}, number = {}, pages = {9-15}, doi = {10.1016/j.scitotenv.2019.02.330}, pmid = {30825823}, issn = {1879-1026}, mesh = {*Biofilms ; *Bioreactors ; High-Throughput Nucleotide Sequencing ; Membranes, Artificial ; Methane/*metabolism ; Methanosarcina/*physiology ; Oxidation-Reduction ; Perchlorates/*metabolism ; Phylogeny ; RNA, Archaeal/analysis ; RNA, Ribosomal, 16S/analysis ; Real-Time Polymerase Chain Reaction ; *Waste Disposal, Fluid ; }, abstract = {A specially designed CH4-based membrane biofilm batch reactor (MBBR) was applied to investigate anaerobic methane oxidation coupled to perchlorate reduction (AnMO-PR). The 0.21 mM ClO4[-] added in the first stage of operation was completely reduced in 28 days, 0.40 mM ClO4[-] was reduced within 23 days in stage 2, and 0.56 mM of ClO4[-] was reduced within 30 days in stage 3. Although some chlorate (ClO3[-]) accumulated, the recovery of Cl[-] was over 92%. Illumina sequencing of the 16S rRNA gene documented that the bacterial community was mainly composed by perchlorate-reducing bacteria (PRB), methanotrophic bacteria, and archaea. Real-time quantitative PCR showed the archaeal 16S rRNA and mcrA genes increased as more ClO4[-] was reduced, and the predominant archaea belonged to Methanosarcina mazei, which is related to ANME-3, an archaeon able to perform reverse methanogenesis. Several pieces of evidence support that ClO4[-] reduction by the MBBR biofilm occurred via a synergism between Methanosarcina and PRB: Methanosarcina oxidized methane through reverse methanogesis and provided electron donor for PRB to reduce ClO4[-]. Because methanotrophs were present, we cannot rule out that they also were involved in AnMO-PR if they received O2 generated by disproportionation of ClO2[-] from the PRB.}, } @article {pmid30825658, year = {2019}, author = {Huerta-Miranda, GA and Arroyo-Escoto, AI and Burgos, X and Juárez, K and Miranda-Hernández, M}, title = {Influence of the major pilA transcriptional regulator in electrochemical responses of Geobacter sulfureducens PilR-deficient mutant biofilm formed on FTO electrodes.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {127}, number = {}, pages = {145-153}, doi = {10.1016/j.bioelechem.2019.02.006}, pmid = {30825658}, issn = {1878-562X}, mesh = {Bacterial Proteins/*genetics ; Bioelectric Energy Sources/microbiology ; *Biofilms/growth & development ; Electric Conductivity ; Electrodes ; Electron Transport ; Fimbriae, Bacterial/*genetics ; Fluorine/chemistry ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Geobacter/*genetics/physiology ; Oxidation-Reduction ; Tin Compounds/chemistry ; Transcription Factors/*genetics ; }, abstract = {Geobacter sulfurreducens is a model organism for understanding the role of bacterial structures in extracellular electron transfer mechanism (EET). This kind of bacteria relies on different structures such as type IV pili and over 100 c-type cytochromes to perform EET towards soluble and insoluble electron acceptors, including electrodes. To our knowledge, this work is the first electrochemical study comparing a G. sulfurreducens PilR-deficient mutant and wild type biofilms developed on fluorine-doped tin oxide (FTO) electrodes. Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), were used to evaluate the electroactive properties of biofilms grown without externally imposed potential. Parallel studies of Confocal Laser Scanning Microscopy (CLSM) correlated with the electrochemical results. PilR is a transcriptional regulator involved in the expression of a wide variety of genes, including pilA (pilus structural protein) relevant c-type cytochromes and some other genes involved in biofilm formation and EET processes. Our findings suggest that PilR-deficient mutant forms a thinner (CLSM analysis) and less conductive biofilm (EIS analysis) than wild type, exhibiting different and irreversible redox processes at the interface (CV analysis). Additionally, this work reinforces some of the remarkable features described in previous reports about this G. sulfurreducens mutant.}, } @article {pmid30825476, year = {2019}, author = {Li, P and Chen, X and Shen, Y and Li, H and Zou, Y and Yuan, G and Hu, P and Hu, H}, title = {Mucus penetration enhanced lipid polymer nanoparticles improve the eradication rate of Helicobacter pylori biofilm.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {300}, number = {}, pages = {52-63}, doi = {10.1016/j.jconrel.2019.02.039}, pmid = {30825476}, issn = {1873-4995}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects/growth & development ; Biopolymers/metabolism ; Cell Adhesion/drug effects ; Cell Line, Tumor ; Chitosan/administration & dosage ; Clarithromycin/*administration & dosage ; Glycolipids/*administration & dosage ; Helicobacter pylori/*drug effects/physiology ; Humans ; Mucus/*metabolism ; Nanoparticles/*administration & dosage ; Polyethylene Glycols/administration & dosage ; }, abstract = {The resistance of Helicobacter pylori (H. pylori) to conventional antibiotic treatments becomes prevalent recently. The biofilm formation was found to be highly correlated with the antibiotic resistance of H. pylori in the last decades. Moreover, H. pylori colonizes on the digestive tract epithelium located under the mucus layers, which further reduces therapeutic efficacy as mucus layers trap and remove exogenous substances including drugs. Herein, we reported a novel lipid polymer nanoparticles (LPNs) to overcome both biofilm and mucus layers obstruction. LPNs employed chitosan nanoparticle (CS NPs) as the core, mixed lipid layer containing rhamnolipids (RHL) as the shell and the surface of LPNs was further modified with DSPE-PEG2000 to improve hydrophilicity. Clarithromycin (CLR), a first-line drug for H. pylori infection, was encapsulated in LPNs. LPNs, especially the formulation utilizing 100% of RHL as the lipid shell, exhibited excellent eradicating ability to H. pylori biofilm, which was mainly reflected in the significant reduction of biofilm biomass and viability, destruction of biofilm architecture and elimination of extracellular polymeric substances (EPS). The anti-biofilm activities of LPNs are related to: 1) the disrupting effect of RHL on biofilm matrix; 2) antibacterial effects of CLR and CS NPs on biofilm bacteria and 3) inhibitory effects of CS NPs and RHL on bacteria adhesion and biofilm formation. Furthermore, PEGylated LPNs could rapidly penetrate through mucus without interacting with mucins and effectively eradicate H. pylori biofilm under mucus layer. In conclusion, a novel approach of drug-containing LPNs that could penetrate through mucus layers and effectively eradicate H. pylori biofilm provides new ways to treat persistent H. pylori infections.}, } @article {pmid30824455, year = {2019}, author = {Jochim, A and Shi, T and Belikova, D and Schwarz, S and Peschel, A and Heilbronner, S}, title = {Methionine Limitation Impairs Pathogen Expansion and Biofilm Formation Capacity.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {9}, pages = {}, pmid = {30824455}, issn = {1098-5336}, mesh = {Biofilms/*drug effects ; Escherichia coli/drug effects/genetics/*physiology ; Methionine/*deficiency ; Mutation ; Pseudomonas aeruginosa/drug effects/genetics/*physiology ; Staphylococcus aureus/drug effects/genetics/*physiology ; }, abstract = {Multidrug-resistant bacterial pathogens are becoming increasingly prevalent, and novel strategies to treat bacterial infections caused by these organisms are desperately needed. Bacterial central metabolism is crucial for catabolic processes and provides precursors for anabolic pathways, such as the biosynthesis of essential biomolecules like amino acids or vitamins. However, most essential pathways are not regarded as good targets for antibiotic therapy since their products might be acquired from the environment. This issue raises doubts about the essentiality of such targets during infection. A putative target in bacterial anabolism is the methionine biosynthesis pathway. In contrast to humans, almost all bacteria carry methionine biosynthesis pathways which have often been suggested as putative targets for novel anti-infectives. While the growth of methionine auxotrophic strains can be stimulated by exogenous methionine, the extracellular concentrations required by most bacterial species are unknown. Furthermore, several phenotypic characteristics of methionine auxotrophs are only partly reversed by exogenous methionine. We investigated methionine auxotrophic mutants of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (all differing in methionine biosynthesis enzymes) and found that each needed concentrations of exogenous methionine far exceeding that reported for human serum (∼30 µM). Accordingly, these methionine auxotrophs showed a reduced ability to proliferate in human serum. Additionally, S. aureus and P. aeruginosa methionine auxotrophs were significantly impaired in their ability to form and maintain biofilms. Altogether, our data show intrinsic defects of methionine auxotrophs. This result suggests that the pathway should be considered for further studies validating the therapeutic potential of inhibitors.IMPORTANCE New antibiotics that attack novel targets are needed to circumvent widespread resistance to conventional drugs. Bacterial anabolic pathways, such as the enzymes for biosynthesis of the essential amino acid methionine, have been proposed as potential targets. However, the eligibility of enzymes in these pathways as drug targets is unclear because metabolites might be acquired from the environment to overcome inhibition. We investigated the nutritional needs of methionine auxotrophs of the pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli We found that each auxotrophic strain retained a growth disadvantage at methionine concentrations mimicking those available in vivo and showed that biofilm biomass was strongly influenced by endogenous methionine biosynthesis. Our experiments suggest that inhibition of the methionine biosynthesis pathway has deleterious effects even in the presence of external methionine. Therefore, additional efforts to validate the effects of methionine biosynthesis inhibitors in vivo are warranted.}, } @article {pmid30820766, year = {2019}, author = {Hamilos, DL}, title = {Biofilm Formations in Pediatric Respiratory Tract Infection : Part 1: Biofilm Structure, Role of Innate Immunity in Protection Against and Response to Biofilm, Methods of Biofilm Detection, Pediatric Respiratory Tract Diseases Associated with Mucosal Biofilm Formation.}, journal = {Current infectious disease reports}, volume = {21}, number = {2}, pages = {6}, pmid = {30820766}, issn = {1523-3847}, abstract = {PURPOSE OF REVIEW: Biofilm represents an organized structure of microorganisms within an extracellular matrix attached to a surface. While the importance of biofilm in prosthetic heart valve and catheter-related infections has been known since the 1980s, the role of mucosal biofilm in human disease pathogenesis has only recently been elucidated. It is now clear that mucosal biofilm is present in both healthy and pathologic states. The purpose of this review is to examine the role of mucosal biofilm in pediatric respiratory infections.

RECENT FINDINGS: Mucosal biofilm has been implicated in relationship to several pediatric respiratory infections, including tonsillitis, adenoiditis, otitis media with effusion, chronic rhinosinusitis, persistent endobronchial infection, and bronchiectasis. In these conditions, core pathogens are detected in the biofilm, biofilm organisms are often detected by molecular techniques when conventional cultures are negative, and biofilm presence is more extensive in relation to disease than in healthy tissues. In chronic rhinosinusitis, the presence of polymicrobial biofilm is also a predictor of poorer outcome following sinus surgery. Biofilm in the tonsillar and adenoidal compartments plays a distinct role in contributing to disease in the middle ear and sinuses. Key observations regarding the relevance of biofilm to pediatric respiratory infections include (1) the association between the presence of biofilm and persistent/recurrent and more severe disease in these tissues despite antibiotic treatment, (2) linkage between biofilm core pathogens and acute infections, and (3) interrelationship between biofilm presence in one tissue and persistent or recurrent infection in an adjacent tissue. A greater understanding of the significance of mucosal biofilm will undoubtedly emerge with the development of effective means of eradicating mucosal biofilm.}, } @article {pmid30820691, year = {2019}, author = {Chen, D and Cao, Y and Yu, L and Tao, Y and Zhou, Y and Zhi, Q and Lin, H}, title = {Characteristics and influencing factors of amyloid fibers in S. mutans biofilm.}, journal = {AMB Express}, volume = {9}, number = {1}, pages = {31}, pmid = {30820691}, issn = {2191-0855}, support = {81570967//National Natural Science Foundation of China/ ; }, abstract = {There are signs that amyloid fibers exist in Streptococcus mutans biofilm recently. However, the characteristics of amyloid fibers and fibrillation influencing factors are unknown. In this study, we firstly used transmission electron microscopy (TEM) and atomic force microscopy (AFM) to observe the morphology of amyloid fibers in S. mutans. Then the extracted amyloid fibers from biofilm were studied for their characteristics. Further, the influencing factors, PH, temperature and eDNA, were investigated. Results showed there were mainly two morphologies of amyloid fibers in S. mutans, different in width. Amyloid fibers inhibitor-EGCG obviously destroyed biofilm at different stages, which is dose-dependent. The amount of amyloid fibers positively correlated with biofilm biomass in clinical isolates. Acidic pH and high temperature obviously accelerated amyloid fibrillation. During amyloid fibrillation, amyloid growth morphologies were observed by TEM and results showed two growth morphologies. Amyloid fibers formed complex with eDNA, which we call (a)eDNA. The molecular weight of (a)eDNA was similar to genomic DNA, greatly larger than that of eDNA in matrix. Combined use of DNase I and EGCG was more efficiently in inhibiting amyloid fibers and biofilm biomass. In conclusion, amyloid fibers are the crucial structures for S. mutans biofilm formation, showing two types of morphology. Acidic pH and temperature can obviously accelerate amyloid fibrillation. Amyloid fibers form complex with (a)eDNA and combined use of DNase and amyloid fiber inhibitor is more efficiently in inhibiting S. mutans biofilm formation.}, } @article {pmid30820334, year = {2019}, author = {Chan, S and Pullerits, K and Keucken, A and Persson, KM and Paul, CJ and Rådström, P}, title = {Bacterial release from pipe biofilm in a full-scale drinking water distribution system.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {9}, pmid = {30820334}, issn = {2055-5008}, mesh = {Bacteria/*classification/genetics/*isolation & purification ; Bacterial Load ; Biofilms/*growth & development ; *Biota ; Cluster Analysis ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Drinking Water/*microbiology ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Sweden ; }, abstract = {Safe drinking water is delivered to the consumer through kilometres of pipes. These pipes are lined with biofilm, which is thought to affect water quality by releasing bacteria into the drinking water. This study describes the number of cells released from this biofilm, their cellular characteristics, and their identity as they shaped a drinking water microbiome. Installation of ultrafiltration (UF) at full scale in Varberg, Sweden reduced the total cell count to 1.5 × 10[3] ± 0.5 × 10[3] cells mL[-1] in water leaving the treatment plant. This removed a limitation of both flow cytometry and 16S rRNA amplicon sequencing, which have difficulties in resolving small changes against a high background cell count. Following installation, 58% of the bacteria in the distributed water originated from the pipe biofilm, in contrast to before, when 99.5% of the cells originated from the treatment plant, showing that UF shifts the origin of the drinking water microbiome. The number of bacteria released from the biofilm into the distributed water was 2.1 × 10[3] ± 1.3 × 10[3] cells mL[-1] and the percentage of HNA (high nucleic acid) content bacteria and intact cells increased as it moved through the distribution system. DESeq2 analysis of 16S rRNA amplicon reads showed increases in 29 operational taxonomic units (OTUs), including genera identified as Sphingomonas, Nitrospira, Mycobacterium, and Hyphomicrobium. This study demonstrated that, due to the installation of UF, the bacteria entering a drinking water microbiome from a pipe biofilm could be both quantitated and described.}, } @article {pmid30820202, year = {2019}, author = {Tahmourespour, A and Kasra-Kermanshahi, R and Salehi, R}, title = {Lactobacillus rhamnosus biosurfactant inhibits biofilm formation and gene expression of caries-inducing Streptococcus mutans.}, journal = {Dental research journal}, volume = {16}, number = {2}, pages = {87-94}, pmid = {30820202}, issn = {1735-3327}, abstract = {BACKGROUND: It is cleared that some probiotic strains inhibit biofilm formation of oral bacteria, but its mechanisms are not clearly understood yet. It is proposed that one of the mechanisms can be biosurfactant production, a structurally diverse group of surface-active compounds synthesized by microorganisms. Hence, this study focused on the evaluation of the anti-biofilm and antiadhesive activities of the L. rhamnosus derived-biosurfactant against Streptococcus mutans and its effect on gtfB/C and ftf genes expression level.

MATERIALS AND METHODS: In this in vitro study Lactobacillus rhamnosus ATCC7469 overnight culture was used for biosurfactant production. The biosurfactant effect on the surface tension reduction was confirmed by drop collapse method. Chemical bonds in the biosurfactant were identified by Fourier transform infrared (FTIR). Anti-biofilm and antiadhesive activities of the biosurfactant were determined on glass slides and in 96-well culture plates, respectively. The effect of the biosurfactant on gtfB/C and ftf genes expression level was also investigated after biofilm formation, total RNA extraction, and reverse transcription by quantitative real-time reverse transcriptase polymerase chain reaction (PCR) assay (quantitative PCR). The data were assessed by one-way analysis of variance in the Tukey-Kramer postdeviation test for all pairs. P < 0.05 was considered statistically significant.

RESULTS: The FTIR results of biosurfactant showed that it was protein rich. It also showed anti-biofilm formation activity on the glass slide and antiadhesive activity till 40% on microtiter plate wells. It also showed a significant reduction (P < 0.05) in gtfB/C and ftf genes expression level.

CONCLUSION: L. rhamnosus-derived biosurfactant exhibits a significant inhibitory effect on biofilm formation ability of S. mutans due to downregulation of biofilm formation associated genes, gtfB/C and ftf. L. rhamnosus-derived biosurfactant with substantial antiadhesive activity is suitable candidates for use in new generations of microbial antiadhesive agents.}, } @article {pmid30818374, year = {2019}, author = {Ong, TH and Chitra, E and Ramamurthy, S and Ling, CCS and Ambu, SP and Davamani, F}, title = {Cationic chitosan-propolis nanoparticles alter the zeta potential of S. epidermidis, inhibit biofilm formation by modulating gene expression and exhibit synergism with antibiotics.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0213079}, pmid = {30818374}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/administration & dosage ; Biofilms/drug effects/growth & development ; Chitosan/*administration & dosage ; Drug Synergism ; Gene Expression/drug effects ; Humans ; Membrane Potentials/drug effects ; Microbial Sensitivity Tests ; Nanoparticles/administration & dosage/chemistry ; Propolis/*administration & dosage ; Staphylococcus epidermidis/*drug effects/genetics/physiology ; }, abstract = {Staphylococcus epidermidis, is a common microflora of human body that can cause opportunistic infections associated with indwelling devices. It is resistant to multiple antibiotics necessitating the need for naturally occurring antibacterial agents. Malaysian propolis, a natural product obtained from beehives exhibits antimicrobial and antibiofilm properties. Chitosan-propolis nanoparticles (CPNP) were prepared using Malaysian propolis and tested for their effect against S. epidermidis. The cationic nanoparticles depicted a zeta potential of +40 and increased the net electric charge (zeta potential) of S. epidermidis from -17 to -11 mV in a concentration-dependent manner whereas, ethanol (Eth) and ethyl acetate (EA) extracts of propolis further decreased the zeta potential from -17 to -20 mV. Confocal laser scanning microscopy (CLSM) depicted that CPNP effectively disrupted biofilm formation by S. epidermidis and decreased viability to ~25% compared to Eth and EA with viability of ~60-70%. CPNP was more effective in reducing the viability of both planktonic as well as biofilm bacteria compared to Eth and EA. At 100 μg/mL concentration, CPNP decreased the survival of biofilm bacteria by ~70% compared to Eth or EA extracts which decreased viability by only 40%-50%. The morphology of bacterial biofilm examined by scanning electron microscopy depicted partial disruption of biofilm by Eth and EA extracts and significant disruption by CPNP reducing bacterial number in the biofilm by ~90%. Real time quantitative PCR analysis of gene expression in treated bacteria showed that genes involved in intercellular adhesion such as IcaABCD, embp and other related genes were significantly downregulated by CPNP. In addition to having a direct inhibitory effect on the survival of S. epidermidis, CPNP showed synergism with the antibiotics rifampicin, ciprofloxacin, vancomycin and doxycycline suggestive of effective treatment regimens. This would help decrease antibiotic treatment dose by at least 4-fold in combination therapies thereby opening up ways of tackling antibiotic resistance in bacteria.}, } @article {pmid30817229, year = {2019}, author = {Noie Oskouie, A and Hasani, A and Ahangarzadeh Rezaee, M and Soroush Bar Haghi, MH and Hasani, A and Soltani, E}, title = {A Relationship Between O-Serotype, Antibiotic Susceptibility and Biofilm Formation in Uropathogenic Escherichia coli.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {6}, pages = {951-958}, doi = {10.1089/mdr.2018.0330}, pmid = {30817229}, issn = {1931-8448}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Child ; Child, Preschool ; Escherichia coli Infections/*drug therapy ; Female ; Humans ; Infant ; Male ; Middle Aged ; Serogroup ; Serotyping/methods ; Urinary Tract Infections/*drug therapy ; Uropathogenic Escherichia coli/*drug effects/*genetics ; Young Adult ; }, abstract = {Uropathogenic Escherichia coli (UPEC) is a well-known pathogen that has perturbed the medical scenario because of its resistance to diverse therapeutic drugs and its ability to form a biofilm. Different O-serogroups are the prevalent cause of urinary tract infections (UTIs) along with their ability to form a biofilm. The present research aimed to assess antibiotic susceptibility, biofilm formation, and serotyping of UPEC isolates in conjunction with the demographic data. Antibiotic susceptibility was determined using the Kirby-Bauer method and biofilm formation was assessed phenotypically and at the molecular level. Serotyping was performed by multiplex PCR. A significant proportion of the total of 120 UPECs was isolated from women (p < 0.05). Most isolates were resistant to cefotaxime, ceftazidime, and tetracycline, but maintained their sensitivity to imipenem. O25, O15, O8, and O75 were the most commonly detected serogroups. Moreover, O25, O15, and O8 were the highest biofilm-producing serogroups among the UPEC isolates. Serogroups O75 and O21 were significantly associated with diabetic patients and subjects with renal disease, respectively (p < 0.05). Overall, our results show that UTI incidence in women should be a subject of concern. The high prevalence of the O25 serogroup associated with a specific antibiotic profile and a high percentage of biofilm formation suggests a close relation between serogroups and characteristic features of UPEC isolates.}, } @article {pmid30816860, year = {2019}, author = {Plattes, M}, title = {Presentation and evaluation of the zero-dimensional biofilm model 0DBFM.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {79}, number = {1}, pages = {35-40}, doi = {10.2166/wst.2018.450}, pmid = {30816860}, issn = {0273-1223}, mesh = {*Biofilms ; *Bioreactors ; Sewage ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {A zero-dimensional biofilm model, i.e. 0DBFM, has been developed for dynamic simulation of moving bed bioreactors (MBBRs). This mini-review aims at presenting and evaluating 0DBFM. 0DBFM is presented in Petersen matrix format and is based on the activated sludge model ASM1, which is an explicit and quite complex model (eight processes, 13 state variables, and 19 parameters) that has found wide application in engineering practice. 0DBFM is thus based on existing knowledge in biological wastewater treatment. The ASM1 approach has been confirmed by respirometry since the resulting respirograms were successfully simulated with ASM1. 0DBFM distinguishes between attached and suspended biomass and incorporates attachment of suspended matter from the bulk liquid onto the biofilm and detachment of biofilm into the bulk liquid. Still, 0DBFM respects the golden rule of modelling, which says that 'models should be as simple as possible and as complex as needed' and resists Occam's razor. The practicability of 0DBFM has been shown on a pilot-scale plant since nine days of wastewater treatment were successfully simulated and effluent quality was dynamically predicted. Finally, 0DBFM can be inspiring and the applicability of 0DBFM to other biofilm systems can be tested.}, } @article {pmid30816484, year = {2019}, author = {Sebaa, S and Boucherit-Otmani, Z and Courtois, P}, title = {Effects of tyrosol and farnesol on Candida albicans biofilm.}, journal = {Molecular medicine reports}, volume = {19}, number = {4}, pages = {3201-3209}, pmid = {30816484}, issn = {1791-3004}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects/*growth & development ; Farnesol/*pharmacology ; Fluorescent Antibody Technique ; Microbial Viability/drug effects ; Phenylethyl Alcohol/*analogs & derivatives/pharmacology ; Quorum Sensing/drug effects ; }, abstract = {The present in vitro study examined the effects of the quorum‑sensing molecules farnesol and tyrosol on the development of Candida albicans biofilm in order to elucidate their role as novel adjuvants in oral hygiene. The investigation was conducted in C. albicans ATCC 10231 and C. albicans isolates from dentures and was performed in flat‑bottomed 96‑well polystyrene plates. Yeast growth and their capacity to form biofilms were evaluated following 24 and 48 h incubations at 37˚C in Sabouraud broth supplemented with 0.001‑3 mM farnesol and/or 1‑20 mM tyrosol. Yeast growth was assessed by turbidimetry and biofilms were quantitated by crystal violet staining, under aerobic and anaerobic conditions. The viability of the fungal cells was controlled by the culture of planktonic cells and by examination of the biofilms using fluorescence microscopy following staining with fluorescein diacetate and ethidium bromide. Farnesol at 3 mM exerted a stronger action when added at the beginning of biofilm formation (>50% inhibition) than when added to preformed biofilms (<10% inhibition). Similarly, tyrosol at 20 mM had a greater effect on biofilm formation (>80% inhibition) than on preformed biofilms (<40% inhibition). Despite significant reductions in attached biomass, yeast growth varied little in the presence of the investigated molecules, as corroborated by the turbidimetry, culture of supernatants on solid culture medium followed by counting of colony‑forming units and viability tests using fluorescence microscopy. At the highest tested concentration, the molecules had a greater effect during the initial phases of biofilm formation. The effect of farnesol during anaerobiosis was not significantly different from that observed during aerobiosis, unlike that of tyrosol during anaerobiosis, which exhibited slightly reduced yeast biofilm inhibition. In conclusion, the present study demonstrated the specific anti‑biofilm effect, independent of fungicidal or fungistatic action, of farnesol and tyrosol, as tested in C. albicans ATCC 10231 and 6 strains isolated from dentures. Prior to suggesting the use of these molecules for preventive purposes in oral hygiene, further studies are required in order to clarify the metabolic pathways and cellular mechanisms involved in their antibiofilm effect, as well as the repercussions on the oral microbiome.}, } @article {pmid30816342, year = {2019}, author = {Ueda, Y and Mashima, K and Miyazaki, M and Hara, S and Takata, T and Kamimura, H and Takagi, S and Jimi, S}, title = {Inhibitory effects of polysorbate 80 on MRSA biofilm formed on different substrates including dermal tissue.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {3128}, pmid = {30816342}, issn = {2045-2322}, mesh = {3T3 Cells ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Mice ; Polysorbates/*pharmacology ; Staphylococcal Infections/prevention & control ; Surface-Active Agents/*pharmacology ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) forms biofilms on necrotic tissues and medical devices, and causes persistent infections. Surfactants act on biofilms, but their mode of action is still unknown. If used in the clinic, cytotoxicity in tissues should be minimized. In this study, we investigated the inhibitory effect of four different surfactants on MRSA biofilm formation, and found that a nonionic surfactant, polysorbate 80 (PS80), was the most suitable. The biofilm inhibitory effects resulted from the inhibition of bacterial adhesion to substrates rather than biofilm disruption, and the effective dose was less cytotoxic for 3T3 fibroblasts. However, the effects were substrate-dependent: positive for plastic, silicon, and dermal tissues, but negative for stainless-steel. These results indicate that PS80 is effective for prevention of biofilms formed by MRSA on tissues and foreign bodies. Therefore, PS80 could be used in medical practice as a washing solution for wounds and/or pretreatment of indwelling catheters.}, } @article {pmid30815321, year = {2019}, author = {Meesilp, N and Mesil, N}, title = {Effect of microbial sanitizers for reducing biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa on stainless steel by cultivation with UHT milk.}, journal = {Food science and biotechnology}, volume = {28}, number = {1}, pages = {289-296}, pmid = {30815321}, issn = {2092-6456}, abstract = {Biofilm is a serious issue in the dairy factory due to it increases the opportunity for microbial contamination. Staphylococcus aureus and Pseudomonas aeruginosa are the bacteria capable to construct the biofilm on materials and equipments. Therefore, the bacterial growth and efficiency of sanitizing agents to solve the problems were evaluated. These bacteria grew well in UHT milk when they were cultivated at 37 °C, especially S. aureus. The exponential growth phase and biofilm on stainless steel were discovered by short contact time at 2 h. The mature stage of biofilm cycle was found at 4 h during bacteria growth and it was continuously constructed until 48 h. The 10, 24, and 48 h-old biofilm adhering on stainless steel were established with oxisan and chlorine used as microbial sanitizers. The 4% of sanitizing agents was the efficiency concentration to reduce biofilm on stainless steel up to 82% when these bacteria grew in UHT milk.}, } @article {pmid30812996, year = {2019}, author = {Murugesan, B and Arumugam, M and Pandiyan, N and Veerasingam, M and Sonamuthu, J and Samayanan, S and Mahalingam, S}, title = {Ornamental morphology of ionic liquid functionalized ternary doped N, P, F and N, B, F-reduced graphene oxide and their prevention activities of bacterial biofilm-associated with orthopedic implantation.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {98}, number = {}, pages = {1122-1132}, doi = {10.1016/j.msec.2019.01.052}, pmid = {30812996}, issn = {1873-0191}, mesh = {Bacterial Infections/*drug therapy ; Biocompatible Materials/chemistry/pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Graphite/*chemistry/*pharmacology ; Ionic Liquids/*chemistry/pharmacology ; Ions/chemistry ; Orthopedic Equipment/*microbiology ; Osteoblasts/microbiology ; Oxides/*chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Tissue Engineering/methods ; }, abstract = {The multifunctional biological active material design for bone tissue engineering is essential to induce osteoblast cell proliferation and attachment. Adhesion of bacteria on biomaterials to produce biofilms can be major contributors to the pathogenesis of implant material associated infections. This research work focuses on NPF& NBF elemental doping and functionalization of reduced graphene oxide using an imidazolium-based ionic liquid such as BMIM PF6 and BMIM BF4 by hydrothermal method. The resulting tri doped reduced graphene oxide (NPF-rGO and NBF-rGO) composite was further used as a scaffold for bone tissue engineering and anti-biofilm activities. The observation of the effect of NPF-rGO and NBF-rGO on the morphology, adhesion and cell proliferation of HOS cell was investigated. Moreover, the tri doped composite tested its antibiofilm properties against B. subtilis, E. coli, K. pneumoniae, and P. aeruginosa pathogenic bacteria. In-vitro studies clearly show the effectiveness of N, P, B, and F doping promoting the rGO mineralization, biocompatibility, and destruction of bacterial biofilm formation. The result of this study suggests that NPF-rGO and NBF-rGO hybrid material will be a promising scaffold for bone reaeration and implantation with a minimal bacterial infection.}, } @article {pmid30811834, year = {2019}, author = {Huigens, RW and Abouelhassan, Y and Yang, H}, title = {Phenazine Antibiotic-Inspired Discovery of Bacterial Biofilm-Eradicating Agents.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {20}, number = {23}, pages = {2885-2902}, pmid = {30811834}, issn = {1439-7633}, support = {R35 GM128621/GM/NIGMS NIH HHS/United States ; R35GM128621//National Institute of General Medical Sciences of the National Institutes of Health/International ; }, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; *Drug Discovery ; HeLa Cells ; Humans ; Mice ; Microbial Sensitivity Tests ; Phenazines/chemical synthesis/*pharmacology ; }, abstract = {Bacterial biofilms are surface-attached communities of slow-growing and non-replicating persister cells that demonstrate high levels of antibiotic tolerance. Biofilms occur in nearly 80 % of infections and present unique challenges to our current arsenal of antibiotic therapies, all of which were initially discovered for their abilities to target rapidly dividing, free-floating planktonic bacteria. Bacterial biofilms are credited as the underlying cause of chronic and recurring bacterial infections. Innovative approaches are required to identify new small molecules that operate through bacterial growth-independent mechanisms to effectively eradicate biofilms. One source of inspiration comes from within the lungs of young cystic fibrosis (CF) patients, who often endure persistent Staphylococcus aureus infections. As these CF patients age, Pseudomonas aeruginosa co-infects the lungs and utilizes phenazine antibiotics to eradicate the established S. aureus infection. Our group has taken a special interest in this microbial competition strategy and we are investigating the potential of phenazine antibiotic-inspired compounds and synthetic analogues thereof to eradicate persistent bacterial biofilms. To discover new biofilm-eradicating agents, we have established an interdisciplinary research program involving synthetic medicinal chemistry, microbiology and molecular biology. From these efforts, we have identified a series of halogenated phenazines (HPs) that potently eradicate bacterial biofilms, and future work aims to translate these preliminary findings into ground-breaking clinical advances for the treatment of persistent biofilm infections.}, } @article {pmid30811615, year = {2019}, author = {Pelling, H and Nzakizwanayo, J and Milo, S and Denham, EL and MacFarlane, WM and Bock, LJ and Sutton, JM and Jones, BV}, title = {Bacterial biofilm formation on indwelling urethral catheters.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {277-293}, doi = {10.1111/lam.13144}, pmid = {30811615}, issn = {1472-765X}, support = {MR/P015956/1//Medical Research Council/United Kingdom ; 206854/Z/17/Z//Wellcome Trust/United Kingdom ; }, mesh = {Biofilms/growth & development ; Catheters, Indwelling/*microbiology ; Humans ; Phage Therapy/methods ; Proteus Infections ; Proteus mirabilis/*growth & development/pathogenicity ; Urease/*therapeutic use ; Urinary Catheterization/*adverse effects ; Urinary Catheters/*microbiology ; Urinary Tract Infections/microbiology/prevention & control ; }, abstract = {Urethral catheters are the most commonly deployed medical devices and used to manage a wide range of conditions in both hospital and community care settings. The use of long-term catheterization, where the catheter remains in place for a period >28 days remains common, and the care of these patients is often undermined by the acquisition of infections and formation of biofilms on catheter surfaces. Particular problems arise from colonization with urease-producing species such as Proteus mirabilis, which form unusual crystalline biofilms that encrust catheter surfaces and block urine flow. Encrustation and blockage often lead to a range of serious clinical complications and emergency hospital referrals in long-term catheterized patients. Here we review current understanding of bacterial biofilm formation on urethral catheters, with a focus on crystalline biofilm formation by P. mirabilis, as well as approaches that may be used to control biofilm formation on these devices. SIGNIFICANCE AND IMPACT OF THE STUDY: Urinary catheters are the most commonly used medical devices in many healthcare systems, but their use predisposes to infection and provide ideal conditions for bacterial biofilm formation. Patients managed by long-term urethral catheterization are particularly vulnerable to biofilm-related infections, with crystalline biofilm formation by urease producing species frequently leading to catheter blockage and other serious clinical complications. This review considers current knowledge regarding biofilm formation on urethral catheters, and possible strategies for their control.}, } @article {pmid30811509, year = {2019}, author = {McGaffey, M and Zur Linden, A and Bachynski, N and Oblak, M and James, F and Weese, JS}, title = {Manual polishing of 3D printed metals produced by laser powder bed fusion reduces biofilm formation.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0212995}, pmid = {30811509}, issn = {1932-6203}, mesh = {Alloys/chemistry/*pharmacology ; Animals ; Biofilms/*drug effects/growth & development ; Bone-Anchored Prosthesis/*microbiology ; Chromium Alloys/chemistry ; Dogs ; Lasers ; Methicillin Resistance/*drug effects ; Microscopy, Electron, Scanning ; Microscopy, Interference ; Powders ; Printing, Three-Dimensional ; Prostheses and Implants ; Sonication ; Stainless Steel/chemistry ; Staphylococcus/drug effects/*physiology ; Surface Properties ; Titanium/chemistry ; }, abstract = {Certain 3D printed metals and surface finishes may be better suited for canine patient specific orthopedic implants on the basis of minimizing potential bacterial biofilm growth. Thirty disks each of titanium alloy, stainless steel, and cobalt chromium alloy were 3D printed via laser powder bed fusion. Fifteen disks of each metal were subsequently polished. After incubation with a robust biofilm-forming methicillin-resistant Staphylococcus pseudintermedius isolate, disks were rinsed and sonicated to collect biofilm bacteria. Serial dilutions were plated on blood agar, and colony forming units were counted log (ln) transformed for analysis of variance. Interference microscopy quantified surface roughness for comparison to biofilm growth. Scanning electron microscopy on both pre- and post-sonicated disks confirmed biofilm presence and subsequent removal, and visualized surface features on cleaned disks. Significantly more bacteria grew on rough versus polished metal preparations (p < 0.0001). Titanium alloy had more bacterial biofilm growth compared to cobalt chromium alloy (p = 0.0001) and stainless steel (p < 0.0001). There were no significant growth differences between cobalt chromium alloy and stainless steel (p = 0.4737). Relationships between biofilm growth and surface roughness varied: positive with the rough preparations and negative with the smooth. Polished preparations had increased variance in surface roughness compared to rough preparations, and within disk variance predominated over between disk variance for all preparations with the exception of rough cobalt chromium alloy and rough stainless steel. Using scanning electron microscopy, bacterial biofilms tended to form in crevices. Overall, manual polishing of 3D printed surfaces significantly reduced biofilm growth, with preparation-specific relationships between surface roughness and biofilm growth. These results suggest that metallic implants produced by laser powder bed fusion should be polished. Further research will elucidate the optimal surface roughness per preparation to reduce potential biofilm formation and implant associated infection.}, } @article {pmid30811265, year = {2019}, author = {Aladarose, BE and Said, HS and Abdelmegeed, ES}, title = {Incidence of Virulence Determinants Among Enterococcal Clinical Isolates in Egypt and Its Association with Biofilm Formation.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {6}, pages = {880-889}, doi = {10.1089/mdr.2018.0320}, pmid = {30811265}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects ; Egypt ; Enterococcus/drug effects/*genetics/*isolation & purification ; Gelatinases/genetics ; Gram-Positive Bacterial Infections/drug therapy/microbiology ; Hemolysin Proteins/genetics ; Humans ; Incidence ; Microbial Sensitivity Tests/methods ; Virulence/*genetics ; Virulence Factors/*genetics ; }, abstract = {Background: Although Enterococci compromise an essential part of normal gut microbiota of both animals and humans, they have emerged as a leading opportunistic pathogen causing infections. The pathogenesis of enterococci is attributed to an array of virulence determinants. Objectives: This study aims to explore the prevalence and characteristics of enterococcal clinical isolates collected from Mansoura University Hospitals, Egypt, assess their ability to form biofilm, and the correlation with virulence determinants and antimicrobial resistance. Materials and Methods: A total of 70 Enterococcal clinical isolates were collected from different clinical sources between June and December 2016. Biofilm formation capacity was assessed, and characterization of virulence factors and antibiotic susceptibility was performed. Clonal relatedness between isolates was assessed using enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) approach. Results and Conclusion: The molecular analysis demonstrated high genetic diversity among enterococcal clinical isolates. The gelE was the most frequently detected gene (91.4%), followed by asa1 (70%), esp (65.7%), and cylA (17.1%), while hyl was not detected in any isolate. Gelatinase activity was detected in 35.7%, while hemolysin and lipase activity was detected in 12.9% and 78.5%, respectively. Most of the enterococcal isolates were biofilm producers, of which 67.1% were strong/moderate biofilm producers. All linezolid-resistant isolates exhibited strong/moderate biofilm formation capacity. Strong/moderate biofilm formation was more frequently observed among esp-positive (esp+) and gelatinase nonproducing (gelatinase-) enterococcal isolates. Multiple regression analysis denoted that esp (odds ratio [OR] 5.371, p = 0.003) and gelatinase production (OR 0.264, p = 0.015) were associated with strong/moderate biofilm formation capacity. These findings suggest that esp gene positivity and gelatinase production may affect biofilm formation capacity among enterococcal clinical isolates.}, } @article {pmid30810917, year = {2018}, author = {Skowron, K and Hulisz, K and Gryń, G and Olszewska, H and Wiktorczyk, N and Paluszak, Z}, title = {Comparison of selected disinfectants efficiency against Listeria monocytogenes biofilm formed on various surfaces.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {21}, number = {1-2}, pages = {23-33}, doi = {10.1007/s10123-018-0002-5}, pmid = {30810917}, issn = {1139-6709}, mesh = {Biofilms/*drug effects ; Colony Count, Microbial ; Disinfectants/*pharmacology ; Hydrogen Peroxide/pharmacology ; Listeria monocytogenes/*drug effects/genetics/physiology ; Random Amplified Polymorphic DNA Technique ; Sodium Hydroxide/pharmacology ; }, abstract = {Listeria monocytogenes is a main etiological factor of listeriosis, spread mainly by food products. In recent years, an increasing number of patients with listeriosis and an augmentation in L. monocytogenes antibiotic resistance, e.g. to penicillin and ampicillin, has been reported. The aim of the study was to characterise the L. monocytogenes strains isolated from fish-processed food products. Species identification, based on the multiplex-PCR reaction, was performed, and the genetic similarity of the isolates was analysed with the RAPD technique. The strains, in the form of planktonic cells and a biofilm, were subjected to drug-susceptibility analysis, and the effect of disinfectants on the bacillus cells was evaluated. All of the analysed strains were of the Listeria monocytogenes species. Three genetically distant strains were detected, i.e. Lm I, Lm II and Lm III. Approximately 66.6% penicillin-resistant and 66.6% cotrimoxazole-resistant strains were found. No erythromycin-resistant strain was detected. The Lm II strain was simultaneously resistant to four antibiotics, i.e. penicillin, ampicillin, meropenem and cotrimoxazole. The strongest biofilm was formed on aluminium foil and the weakest on rubber. The tested disinfectant antibiofilm effectiveness was related to the type of surface. The most effective agent was paracetic acid and hydrogen peroxide (elimination rate 5.10-6.62 log CFU × cm[-2] and 5.70-7.39 log CFU × cm[-2] after 1- and 5-min exposure, respectively) and the least-sodium hydroxide (elimination rate 0.52-1.20 log CFU × cm[-2] and 0.98-1.81 log CFU × cm[-2] after 1- and 5-min exposure, respectively). Further studies on a greater number of L. monocytogenes strains are recommended.}, } @article {pmid30810004, year = {2018}, author = {Szymanek-Majchrzak, K and Wodzyńska, S and Młynarczyk, A and Młynarczyk, G}, title = {Production of extracellular polysaccharide and biofilm under different oxygen conditions by clinical isolates of Staphylococcus aureus non-susceptible to glycopeptides.}, journal = {Przeglad epidemiologiczny}, volume = {72}, number = {4}, pages = {487-498}, doi = {10.32394/pe.72.4.24}, pmid = {30810004}, issn = {0033-2100}, mesh = {Aerobiosis ; Anaerobiosis ; *Biofilms ; Glycosaminoglycans/*biosynthesis ; Humans ; Methicillin-Resistant Staphylococcus aureus/*metabolism/physiology ; *Oxidative Stress ; Oxygen/pharmacology ; Staphylococcal Infections/metabolism/*microbiology/physiopathology ; *Vancomycin Resistance ; }, abstract = {INTRODUCTION: Staphylococcus aureus, which is able to produce an extracellular mucopolysaccharide (MP) and biofilm (SP), is an important etiologic agent in persistent and implant-related infections. This phenotype may be expressed in different levels and character depending on various environmental and/or global intracellular regulatory mechanisms. It may also be induced by sub-inhibitory concentrations of some antibiotics, for example vancomycin. The main aim of the study was to assess the ability to produce MP and SP in different oxygen conditions by clinical isolates of S.aureus nonsusceptible to glycopeptides.

MATERIALS AND METHODS: Clinical isolates of health-care associated methicillin resistant S. aureus (HA-MRSA) strains, non-susceptible to glycopeptides (GRSA, 47) and heterogeneous vancomycin intermediate S. aureus isolates (h-VISA, 8). Control group consisted of the following strains: 55 belonging to MRSA, vancomycin susceptible, VSSA and 19 as methicillin susceptible, MSSA/VSSA. The ability to produce MP was investigated according to Freeman method. SP production was tested by means of Christensen procedure.

RESULTS: In aerobic conditions MRSA/GRSA and MRSA/h-VISA isolates were the strongest mucopolysaccharide (SMP) producers (12.2% and 28.6% SMP/MP), but MSSA/VSSA were the most frequent MP (100%). In anaerobic atmosphere, all isolates from all groups were MP-positive. MRSA/h-VISA were the strongest MP producers (75% SMP/MP), but MSSA/VSSA were the most susceptible to oxidative stress (the percentage of SMP among MP for MSSA/VSSA increased by 15.8 times). Each evaluated group of clinical S. aureus isolates in aerobic condition had representation in SP positive phenotype: MRSA/GRSA and MRSA/h-VISA, 63.9% and 62.5%; MRSA/VSSA and MSSA/VSSA, respectively 80% and 94.7%. For all mentioned groups of bacteria, SSP variants were present and the amount of values was higher than in similar results obtained in CRA method. The strongest slime producers (60%) were h-VISA strains. The results obtained in Christensen method for anaerobic conditions, were not conclusive due to insufficient optimization of the test parameters.

SUMMARY AND CONCLUSIONS: Both methods reveal that MRSA isolates non-susceptible to glycopeptides are the strongest producers of both MP and SP. That is probably due to cell wall alterations and global regulatory system Agr disorders. The Christensen procedure allow to assess both ica- dependent and ica- independent (adhesive) mechanisms of slime production and allow to notice that, as a phenotyping “biofilm booster effect”. ica- dependent mechanism, which dominated in MSSA/VSSA strains, demonstrate phenotype with more susceptibility to oxygen stress conditions than adhesive one.}, } @article {pmid30809273, year = {2019}, author = {Yang, L and Zheng, C and Chen, Y and Shi, X and Ying, Z and Ying, H}, title = {Nitric oxide increases biofilm formation in Saccharomyces cerevisiae by activating the transcriptional factor Mac1p and thereby regulating the transmembrane protein Ctr1.}, journal = {Biotechnology for biofuels}, volume = {12}, number = {}, pages = {30}, pmid = {30809273}, issn = {1754-6834}, abstract = {BACKGROUND: Biofilms with immobilized cells encased in extracellular polymeric substance are beneficial for industrial fermentation. Their formation is regulated by various factors, including nitric oxide (NO), which is recognized as a quorum-sensing and signal molecule. The mechanisms by which NO regulates bacterial biofilms have been studied extensively and deeply, but were rarely studied in fungi. In this study, we observed the effects of low concentrations of NO on biofilm formation in Saccharomyces cerevisiae. Transcriptional and proteomic analyses were applied to study the mechanism of this regulation.

RESULTS: Adding low concentrations of NO donors (SNP and NOC-18) enhanced biofilm formation of S. cerevisiae in immobilized carriers and plastics. Transcriptional and proteomic analyses revealed that expression levels of genes regulated by the transcription factor Mac1p was upregulated in biofilm cells under NO treatment. MAC1 promoted yeast biofilm formation which was independent of flocculation gene FLO11. Increased copper and iron contents, both of which were controlled by Mac1p in the NO-treated and MAC1-overexpressing cells, were not responsible for the increased biofilm formation. CTR1, one out of six genes regulated by MAC1, plays an important role in biofilm formation. Moreover, MAC1 and CTR1 contributed to the cells' resistance to ethanol by enhanced biofilm formation.

CONCLUSIONS: These findings suggest that a mechanism for NO-mediated biofilm formation, which involves the regulation of CTR1 expression levels by activating its transcription factor Mac1p, leads to enhanced biofilm formation. The role of CTR1 protein in yeast biofilm formation may be due to the hydrophobic residues in its N-terminal extracellular domain, and further research is needed. This work offers a possible explanation for yeast biofilm formation regulated by NO and provides approaches controlling biofilm formation in industrial immobilized fermentation by manipulating expression of genes involved in biofilm formation.}, } @article {pmid30809097, year = {2019}, author = {Zhang, Q and Gao, HY and Li, D and Li, Z and Qi, SS and Zheng, S and Bai, CS and Zhang, SH}, title = {Clinical outcome of Escherichia coli bloodstream infection in cancer patients with/without biofilm formation: a single-center retrospective study.}, journal = {Infection and drug resistance}, volume = {12}, number = {}, pages = {359-371}, pmid = {30809097}, issn = {1178-6973}, abstract = {BACKGROUND: Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is one of the main antimicrobial-resistant pathogens. Little data are available on how biofilm formation (BF) contributes to EC-caused bloodstream infection (BSI) in cancer patients. This study investigated the impact of BF on clinical outcomes of cancer patients with EC-caused BSI.

METHODS: Clinical outcome and microbiological characteristics including the presence of bla genes in ESBL-EC isolates were retrospectively collected from BSI cancer patients. Patients infected with ESBL-EC were compared with patients infected with third-generation cephalosporin-susceptible strains. Survival curves were generated by Kaplan-Meier analysis and the survival difference was assessed by the log-rank test. Risk factors for ESBL-EC infection, predictors of mortality, and outcome differences were determined by multivariate logistic regression and Cox regression analysis, respectively.

RESULTS: A high prevalence of ESBL-EC with dominant bla CTX-M-15, bla CTX-M-15 plus bla TEM-52 genotype was found in BSI cancer patients. Independent risk factors for infection with ESBL-EC were cephalosporins, chemotherapy, and BF. Metastasis, ICU admission, BF-positive ESBL-EC, organ failure, and the presence of septic shock were revealed as predictors for mortality. The ESBL characteristic was associated with the BF phenotype, and the overall mortality was significantly higher in cancer patients with BF-positive ESBL-EC-caused BSI.

CONCLUSION: bla CTX-M-15 type ESBL-EC is highly endemic among cancer patients with BSI. BF is associated with multi-drug resistance by ESBL-EC and is also an independent risk factor of mortality for cancer patients with BSI. Our findings suggest that the combination of BF-positive ESBL-EC isolates with other appropriate laboratory indicators might benefit infection control and improve clinical outcomes.}, } @article {pmid30808968, year = {2019}, author = {Cabal, B and Sevillano, D and Fernández-García, E and Alou, L and Suárez, M and González, N and Moya, JS and Torrecillas, R}, title = {Bactericidal ZnO glass-filled thermoplastic polyurethane and polydimethyl siloxane composites to inhibit biofilm-associated infections.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {2762}, pmid = {30808968}, issn = {2045-2322}, mesh = {Aluminum Oxide/chemistry ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects ; Boron Compounds/chemistry ; Dimethylpolysiloxanes/*chemistry ; Erythrocytes/cytology/metabolism ; Glass/*chemistry ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Hemolysis/drug effects ; Humans ; Microbial Sensitivity Tests ; Oxides/chemistry ; Polyurethanes/*chemistry ; Silicon Dioxide/chemistry ; Sodium Compounds/chemistry ; Staphylococcus epidermidis/physiology ; Surface Properties ; Tensile Strength ; Zinc Oxide/*chemistry ; }, abstract = {This study investigates a novel approach to controlling biofilms of the most frequent pathogens implicated in the etiology of biomaterials-associated infections. New bactericidal filler based on a non-toxic glass, belonging to B2O3-SiO2-Al2O3-Na2O-ZnO system, was used to formulate composites of the most widely used polymers in biomedical applications [i.e. thermoplastic polyurethane (TPU) and polydimethyl siloxane (PDMS)], with varying percentage by weight of the bactericidal glass (5, 15, 25, 35, 50%). Glass-filled polymer composites show dramatically restricted bacterial colonisation and biofilm formation. They exhibit time- and dose-dependent killing, with maximal action at 5 days. The highest activity was found against S.epidermidis biofilm (99% of reduction), one of the most common cause of nosocomial infections. The tensile properties of the obtained glass-filled composites are comparable with the literature data concerning polymeric biomaterials for medical implants and devices. In addition, all the materials presented in this research, revealed an excellent biocompatibility. This was disclosed by cell viability values above 70%, none alteration on erythrocyte membrane or cell functionality in contact with materials (haemolytic index 0-2%), and absence of interferences in blood coagulation (intrinsic, extrinsic and final pathways).}, } @article {pmid30808878, year = {2019}, author = {de Barros Pinto, L and Lira, MLLA and Cavalcanti, YW and Dantas, ELA and Vieira, MLO and de Carvalho, GG and de Sousa, FB}, title = {Natural enamel caries, dentine reactions, dentinal fluid and biofilm.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {2841}, pmid = {30808878}, issn = {2045-2322}, mesh = {*Biofilms ; Dental Caries/diagnostic imaging/*metabolism/*microbiology ; Dental Enamel/*microbiology ; Dentin/diagnostic imaging/*metabolism ; Dentinal Fluid/diagnostic imaging/*metabolism ; Humans ; Surface Properties ; X-Ray Microtomography ; }, abstract = {It is believed that penetration of dentinal fluid into natural enamel caries (NEC) is negligible because of the barrier created by underlying sclerotic dentine, but there are conflicting evidences on whether dentine subjacent to NEC is sclerotic or demineralized. This study aimed at investigating the relationship between NEC, subjacent dentine reactions, modification of dentinal fluid, and composition of cariogenic biofilm formed on the NEC surface. Proximal NEC (PNEC) lesions of human permanent posterior teeth were included in five experiments. Histologically, microradiographic analysis with contrast solution (MRC) in dentine revealed a decreased proportion of sclerotic dentine and an increased proportion of deep dentine demineralization compared to the classical stereomicroscopic histological analysis based on dentin color and translucency. Real-time MRC and 3D optical profilometry, and 3D microtomographic analysis evidenced a facilitated transport of modified dentinal fluid towards PNEC lesions. Cariogenic biofilm formed in vitro on the PNEC surface presented lower amounts of insoluble and soluble matrix polysaccharides when 2% chlorexidine was inserted in the pulp chamber. In conclusion, this study evidenced that dentine subjacent to PNEC is mostly demineralized, providing facilitated pathway for dentinal fluid to penetrate into PNEC and alter the composition of the biofilm formed on the PNEC surface.}, } @article {pmid30808696, year = {2019}, author = {Huang, Z and Wang, YH and Zhu, HZ and Andrianova, EP and Jiang, CY and Li, D and Ma, L and Feng, J and Liu, ZP and Xiang, H and Zhulin, IB and Liu, SJ}, title = {Cross Talk between Chemosensory Pathways That Modulate Chemotaxis and Biofilm Formation.}, journal = {mBio}, volume = {10}, number = {1}, pages = {}, pmid = {30808696}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; *Chemotaxis ; Comamonas testosteroni/genetics/*physiology ; *Gene Expression Regulation, Bacterial ; *Gene Regulatory Networks ; Histidine Kinase/metabolism ; Phosphorylation ; Protein Processing, Post-Translational ; Signal Transduction ; }, abstract = {Complex chemosensory systems control multiple biological functions in bacteria, such as chemotaxis, gene regulation, and cell cycle progression. Many species contain more than one chemosensory system per genome, but little is known about their potential interplay. In this study, we reveal cross talk between two chemosensory pathways that modulate chemotaxis and biofilm formation in Comamonas testosteroni We demonstrate that some chemoreceptors that govern chemotaxis also contribute to biofilm formation and these chemoreceptors can physically interact with components of both pathways. Finally, we show that the chemotaxis histidine kinase CheA can phosphorylate not only its cognate response regulator CheY2 but also one of the response regulators from the pathway mediating biofilm formation, FlmD. The phosphoryl group transfer from CheA to CheY2 is much faster than that from CheA to FlmD, which is consistent with chemotaxis being a fast response and biofilm formation being a much slower developmental process. We propose that cross talk between chemosensory pathways may play a role in coordination of complex behaviors in bacteria.IMPORTANCE In many bacteria, two or more homologous chemosensory pathways control several cellular functions, such as motility and gene regulation, in response to changes in the cell's microenvironment. Cross talk between signal transduction systems is poorly understood; while generally it is considered to be undesired, in some instances it might be beneficial for coregulation of complex behaviors. We demonstrate that several receptors from the pathway controlling motility can physically interact with downstream components of the pathway controlling biofilm formation. We further show that a kinase from the pathway controlling motility can also phosphorylate a response regulator from the pathway controlling biofilm formation. We propose that cross talk between two chemosensory pathways might be involved in coordination of two types of cell behavior-chemotaxis and biofilm formation.}, } @article {pmid30807627, year = {2019}, author = {Ishijima, M and de Avila, ED and Nakhaei, K and Shi, W and Lux, R and Ogawa, T}, title = {Ultraviolet Light Treatment of Titanium Suppresses Human Oral Bacterial Attachment and Biofilm Formation: A Short-Term In Vitro Study.}, journal = {The International journal of oral & maxillofacial implants}, volume = {34}, number = {5}, pages = {1105–1113}, doi = {10.11607/jomi.7444}, pmid = {30807627}, issn = {1942-4434}, mesh = {Bacteria ; *Biofilms ; *Dental Implants ; Humans ; Surface Properties ; Titanium ; Ultraviolet Rays ; }, abstract = {PURPOSE: Antibacterial dental implants and related prosthetic components could help to reduce infection and prevent peri-implantitis. The purpose of this study was to determine the effect of ultraviolet (UV) light treatment of titanium on biofilm formation of human oral bacteria.

MATERIALS AND METHODS: Machine-prepared commercially pure titanium disks were treated with UV light for 12 minutes. Human oral bacteria were seeded onto untreated and UV-treated disks. Early bacterial attachment to titanium was assessed at 12 hours. Surface topography of initial biofilms was evaluated by 3D scanning electron microscopy at 24 hours. The quantity and morphology of subsequent colony development and biofilm formation were examined by confocal laser scanning microscopy for up to 7 days.

RESULTS: Throughout the time course, significantly fewer bacterial cells attached to UV-treated titanium surfaces compared to untreated ones. While biofilm developed rapidly to a final thickness of about 16 μm by day 3 on untreated titanium, on UV-treated surfaces it remained below 8 μm, even at day 7. Similarly, UV treatment resulted in 70% less exopolysaccharides (EPS) volume than on untreated surfaces at day 7. This is consistent with the finding that EPS production per cell was significantly lower on UV-treated surfaces. Untreated titanium surfaces covered with biofilm were 5-fold rougher than the original machined surface, while UV-treated surfaces remained 2-fold rougher due to a significantly less biofilm formation.

CONCLUSION: UV treatment of titanium surfaces significantly reduces attachment of human oral bacteria and subsequent biofilm formation as well as EPS production for at least 7 days. UV treatment prevented the escalation of surface colonization, mitigating an unfavorable bacteriophilic cascade and environmental trigger for biofilm formation.}, } @article {pmid30806125, year = {2019}, author = {Kania, R and Vironneau, P and Dang, H and Bercot, B and Cambau, E and Verillaud, B and Camous, D and Lamers, G and Herman, P and Vicaut, E and Tessier, N and Van Den Abbeele, T}, title = {Bacterial biofilm in adenoids of children with chronic otitis media. Part I: a case control study of prevalence of biofilms in adenoids, risk factors and middle ear biofilms.}, journal = {Acta oto-laryngologica}, volume = {139}, number = {4}, pages = {345-350}, doi = {10.1080/00016489.2019.1571282}, pmid = {30806125}, issn = {1651-2251}, mesh = {Adenoidectomy ; Adenoids/*microbiology ; *Biofilms ; Case-Control Studies ; Child ; Child, Preschool ; Chronic Disease ; Ear, Middle/*microbiology ; Humans ; Infant ; Otitis Media/*microbiology/surgery ; Prospective Studies ; Risk Factors ; }, abstract = {BACKGROUND: Biofilms are communities of bacteria embedded in a self-produced glycocalyx matrix. Adenoids have been shown to harbor bacterial biofilms. Aim/objectives: To compare the prevalence of biofilms in adenoid of children with chronic otitis media (COM) (group1) versus a control group without any COM (group 2) having adenoids removed because of hypertrophy.

MATERIAL AND METHODS: One hundred and three children were prospectively enrolled in this case-control study, group 1 (n = 52) and group 2 (n = 51). The main outcome measurement was the prevalence of biofilm in adenoidectomy specimens analyzed using confocal laser scanning microscopy. Children in group 1 who had middle ear (ME) effusion and requiring the insertion of a tympanostomy tube underwent biopsy of the ME mucosa and effusion sampling.

RESULTS: Biofilms were found in adenoids' specimens of both groups and in the ME biopsy and effusion. The biofilm prevalence in adenoids was 63.5% (33/52) in group 1 and 47.1% (24/51) in group 2. Day nursery and previous antibiotics intake were significantly more frequent in group 1 than in group 2.

CONCLUSIONS AND SIGNIFICANCE: This case-control study demonstrates that adenoid tissue in children with COM contains more mucosal biofilms than adenoid tissue removed for hypertrophy. Biofilm was seen in ME biopsies and effusion.}, } @article {pmid30805398, year = {2019}, author = {Shahmoradi, M and Faridifar, P and Shapouri, R and Mousavi, SF and Ezzedin, M and Mirzaei, B}, title = {Determining the Biofilm Forming Gene Profile of Staphylococcus aureus Clinical Isolates via Multiplex Colony PCR Method.}, journal = {Reports of biochemistry & molecular biology}, volume = {7}, number = {2}, pages = {181-188}, pmid = {30805398}, issn = {2322-3480}, abstract = {BACKGROUND: Among hospitalized patients, Staphylococcus aureus (S. aureus) infections pose a serious health threat. The present study investigated the frequency of biofilm forming genes among clinical isolates S. aureus and their susceptibility to antibiotics.

METHODS: The clinical samples were analyzed via standard biochemical assays for identifying different bacterium, which was then confirmed using the multiplex colony PCR method. Those samples identified as S. aureus were examined for the presence of the cna, fnbA, fnbB and pvl genes. The antibiotic susceptibility of the S. aureus isolates was then tested.

RESULTS: Using the standard biochemical assay approach, 54 S. aureus strains were identified. However, when using the multiplex PCR method 50 S. aureus strains were identified among the clinical samples. The in vitro biofilm formation assays determined 3 (6%) strains of S. aureus to be strong biofilm forming, 15 (30%) of the isolates were determined to be moderate biofilm forming and, 32 (64%) were determined to be weak biofilm forming. Among the isolated strains, the specific frequencies of the biofilm forming genes were determined to be 31 (62%) for cna, 35 (70%) for fnbA, 13 (26%) for fnbB and 1 (2%) for pvl. In 11 (22%) of the isolated strains fnbA, fnbB and cna genes were all present. All strains were determined to be penicillin, amoxicillin and clavulanic acid resistant.

CONCLUSION: Due to the increase of the antibiotic resistance in biofilm producing S. aureus strains, rapid identification of antibiotic resistance can help to eliminate the infection effectively.}, } @article {pmid30805068, year = {2019}, author = {Filardo, S and Di Pietro, M and Tranquilli, G and Sessa, R}, title = {Biofilm in Genital Ecosystem: A Potential Risk Factor for Chlamydia trachomatis Infection.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2019}, number = {}, pages = {1672109}, pmid = {30805068}, issn = {1712-9532}, abstract = {In healthy women, the cervicovaginal microbiota is mostly populated by Lactobacillus spp., the main host defense factor of the female genital tract. In addition to Lactobacilli, other microorganisms populate the cervicovaginal microbiota, like Candida spp. and Gardnerella vaginalis. The overgrowth of Candida spp. or G. vaginalis, known as biofilm-producing microorganisms in the genital ecosystem, may lead to microbial dysbiosis that increases the risk of acquiring sexually transmitted infections, like Chlamydia trachomatis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is still considered an important public health problem worldwide because of the impact of asymptomatic infections on long-term reproductive sequelae, including pelvic inflammatory disease and infertility. The aim of our study was to investigate the interaction between C. trachomatis and the biofilm produced by Candida albicans or Gardnerella vaginalis, evaluating whether the biofilm can harbor C. trachomatis and influence its survival as well as its infectious properties. In order to do so, we developed an in vitro coculture transwell-based biofilm model. Our findings proved, for the first time, that C. trachomatis, an intracellular obligate pathogen, survived, for up to 72 hours after exposure, inside the biofilm produced by C. albicans or G. vaginalis, retaining its infectious properties, as evidenced by the typical chlamydial inclusions observed in the cell monolayer (chlamydial inclusion-forming units at 72 h: 9255 ± 1139 and 9873 ± 1015, respectively). In conclusion, our results suggest that the biofilm related to Candida or Gardnerella genital infections may act as a reservoir of C. trachomatis and, thus, contribute to the transmission of the infection in the population as well as to its dissemination into the upper genital tract, increasing the risk of developing severe reproductive sequelae.}, } @article {pmid30804914, year = {2019}, author = {Wang, Y and Wang, F and Wang, C and Li, X and Fu, L}, title = {Positive Regulation of Spoilage Potential and Biofilm Formation in Shewanella baltica OS155 via Quorum Sensing System Composed of DKP and Orphan LuxRs.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {135}, pmid = {30804914}, issn = {1664-302X}, abstract = {The spoilage potential and biofilm formation of Shewanella baltica are reported to be regulated by Quorum sensing (QS) system from the phenotype point of view, but the specific mechanism is not fully understood. In the present study, the QS autoinducers were detected by UHPLC-MS/MS, cell density-dependent luxR-type genes were obtained through autoregulation experiments among a series of candidates in S. baltica OS155 (The SSO of large yellow croaker). The direct interaction between cyclo-(L-Pro-L-Phe) (PP) and LuxR01 as well as LuxR02 proteins was revealed via in vitro binding assay. Deletion of luxR-type genes (luxR01 and luxR02) impaired spoilage potential and biofilm formation of S. baltica OS155 in various degrees. Transcriptional analysis and qRT-PCR validation showed that spoilage and biofilm-related genes torS, speF, and pomA were down-regulated in luxR01 and luxR02 deletion strains. In addition, exogenous PP promoted spoilage potential and biofilm formation, which could be attenuated by luxR01 or luxR02 deletion. Our results revealed an explicit QS system employing PP as autoinducer and two orphan LuxRs as receptors which positively regulated spoilage capacity and biofilm formation via transcriptional regulation of corresponding genes in S. baltica OS155, which provides potential specific targets for seafood preservation involving QS system.}, } @article {pmid30803538, year = {2019}, author = {Kim, AR and Ahn, KB and Yun, CH and Park, OJ and Perinpanayagam, H and Yoo, YJ and Kum, KY and Han, SH}, title = {Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm.}, journal = {Journal of endodontics}, volume = {45}, number = {3}, pages = {310-315}, doi = {10.1016/j.joen.2018.12.007}, pmid = {30803538}, issn = {1878-3554}, mesh = {Actinomyces/pathogenicity/*physiology ; Biofilms/*drug effects ; Calcium Hydroxide/pharmacology ; Chlorhexidine/analogs & derivatives/pharmacology ; Dentin/microbiology ; Depression, Chemical ; Dose-Response Relationship, Drug ; Enterococcus faecalis/pathogenicity/*physiology ; Humans ; Lactobacillus plantarum/*chemistry ; Ligilactobacillus salivarius/pathogenicity/*physiology ; Lipopolysaccharides/*isolation & purification/*pharmacology/therapeutic use ; Periapical Periodontitis/drug therapy/microbiology/prevention & control ; Root Canal Irrigants/pharmacology ; Teichoic Acids/*isolation & purification/*pharmacology/therapeutic use ; }, abstract = {INTRODUCTION: Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.

METHODS: Highly pure and structurally intact Lp.LTA was purified from L. plantarum. Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans, and Enterococcus faecalis were co-cultured to form oral multispecies biofilm in the presence or absence of Lp.LTA on culture plates or human dentin slices. Preformed biofilm was treated with or without Lp.LTA, followed by additional treatment with intracanal medicaments such as calcium hydroxide or chlorhexidine digluconate. Confocal microscopy and crystal violet assay were performed to determine biofilm formation. Biofilm on human dentin slices was visualized with a scanning electron microscope.

RESULTS: Biofilm formation of multispecies bacteria on the culture dishes was dose-dependently reduced by Lp.LTA compared with the nontreatment control group. Lp.LTA also inhibited multispecies biofilm formation on the dentin slices in a dose-dependent manner. Interestingly, Lp.LTA was shown to reduce preformed multispecies biofilm compared with the nontreatment group. Moreover, Lp.LTA potentiated the effectiveness of the intracanal medicaments in the removal of preformed multispecies biofilm.

CONCLUSIONS: These results suggest that Lp.LTA is a potential anti-biofilm agent for treatment or prevention of oral infectious disease, including apical periodontitis, which is mainly caused by multispecies bacterial biofilm.}, } @article {pmid30803536, year = {2019}, author = {Wu, S and Liu, Y and Zhang, H and Lei, L}, title = {The Susceptibility to Calcium Hydroxide Modulated by the Essential walR Gene Reveals the Role for Enterococcus faecalis Biofilm Aggregation.}, journal = {Journal of endodontics}, volume = {45}, number = {3}, pages = {295-301.e2}, doi = {10.1016/j.joen.2018.11.011}, pmid = {30803536}, issn = {1878-3554}, mesh = {Adaptation, Physiological/genetics ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/*physiology ; *Biofilms ; Calcium Hydroxide/*pharmacology ; Dental Pulp Cavity/microbiology ; Drug Resistance, Bacterial/*genetics ; Enterococcus faecalis/drug effects/*genetics/pathogenicity/*physiology ; Genes, Bacterial/*genetics/*physiology ; Humans ; Periapical Periodontitis/microbiology ; Pulpitis/microbiology ; Virulence/genetics ; }, abstract = {INTRODUCTION: Enterococcus faecalis is considered a predominant pathogen for persistent periapical infections and in addition is reportedly resistant to calcium hydroxide medication. The WalRK 2-component system of E. faecalis is essential for environmental adaptation, survival, and virulence. The goal of this study was to investigate the potential roles of walR in the regulation of biofilm aggregation, alkaline stress, and susceptibility to calcium hydroxide (CH) medication.

METHODS: Antisense walR RNA (aswalR) overexpression strains were constructed. Exopolysaccharide (EPS) production and bacterial viability of E. faecalis biofilms were evaluated by confocal laser scanning microscopy. Quantitative real-time polymerase chain reaction was used to investigate the expressions of virulent factor genes. The proportion of viable bacteria and EPS production in dentin were assessed after CH medication.

RESULTS: We showed that walR interference by aswalR RNA leads to a reduction in the dextran-dependent aggregation in E. faecalis biofilm. The overexpression of aswalR reduced the transcripts of the virulence genes and alkaline stress tolerance ability. Furthermore, the down-regulation of walR sensitized E. faecalis in infected canals to CH medication associated with inhibiting EPS synthesis.

CONCLUSIONS: The data suggest a role for the walR regulator in the susceptibility to CH associated with dispelling the EPS matrix, which could be explored as a potential supplementary therapy for the management of root canal infection.}, } @article {pmid30803159, year = {2019}, author = {Hengzhuang, W and Green, K and Pressler, T and Skov, M and Katzenstein, TL and Wu, X and Høiby, N}, title = {Optimization of colistin dosing regimen for cystic fibrosis patients with chronic Pseudomonas aeruginosa biofilm lung infections.}, journal = {Pediatric pulmonology}, volume = {54}, number = {5}, pages = {575-580}, doi = {10.1002/ppul.24269}, pmid = {30803159}, issn = {1099-0496}, mesh = {Adult ; Anti-Bacterial Agents/*administration & dosage/metabolism/pharmacology ; *Biofilms ; Colistin/administration & dosage/*analogs & derivatives/metabolism/pharmacology ; Cystic Fibrosis/*complications ; Female ; Humans ; Infusions, Intravenous ; Lung ; Male ; Microbial Sensitivity Tests ; Monte Carlo Method ; Pneumonia, Bacterial/complications/*drug therapy ; Pseudomonas Infections/complications/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {OBJECTIVE: The present study was performed to explore dosing regimens of colistin in patients of cystic fibrosis (CF) with Pseudomonas aeruginosa chronic biofilm lung infection.

METHODS: Ten CF patients were involved. One dose colistimethate sodium (CMS) of 6 MIU (million international units) and 9 MIU were administered by intravenous infusion over 45 and 90 min. Venous blood was collected at different time points after the infusion of CMS. Pharmacokinetic parameters of colistin were calculated. Minimum inhibitory concentration for planktonic P. aeruginosa, minimum biofilm inhibitory concentration and minimum biofilm eradication concentration of P. aeruginosa were determined. Monte Carlo simulation was performed to determine the clinical probability of target attainment of different dosing regimens of colistin in CF patients.

RESULTS: For 90 min (6 MIU), 45 min (6 MIU), and 45 min (9 MIU) intravenous infusion of colistin, Cmax was 8.9 ± 1.8, 15 ± 5.5, and 31.7 ± 5.3 μg/mL, respectively; Tmax was 1.2 ± 0.4, 0.7 ± 0.2, and 0.8 ± 0.2 h, respectively; AUCtot were 31 ± 3.8, 34 ± 10, and 135 ± 31mg · h/L, respectively; t1/2 was 2.1 ± 0.4, 2 ± 0.3, and 3.3 ± 0.4 h, respectively. MBIC and MBEC of colistin on biofilms at 24 h period treatment were 16-128 μg/mL for non-mucoid and mucoid biofilms of P. aeruginosa. For 90 min (6 MIU), 45 min (6 MIU) and 45 min iv infusion (9 MIU) with one dose colistin, PTA was 49.8%, 53.8%, 99.4% for planktonic infection, and 11.3%, 14.6%, 65.3%, respectively for biofilm infection.

CONCLUSIONS: colistin treatment using 45 min iv infusion is better than 90 min iv infusion in this study. Colistin dosage of 9 MIU is better than 6 MIU on both planktonic and biofilm infections of P. aeruginosa in this study.}, } @article {pmid30803151, year = {2019}, author = {Khan, I and Kanugala, S and Shareef, MA and Ganapathi, T and Shaik, AB and Shekar, KC and Kamal, A and Kumar, CG}, title = {Synthesis of new bis-pyrazole linked hydrazides and their in vitro evaluation as antimicrobial and anti-biofilm agents: A mechanistic role on ergosterol biosynthesis inhibition in Candida albicans.}, journal = {Chemical biology & drug design}, volume = {94}, number = {1}, pages = {1339-1351}, doi = {10.1111/cbdd.13509}, pmid = {30803151}, issn = {1747-0285}, mesh = {Anti-Infective Agents/*chemical synthesis/chemistry/pharmacology ; Antifungal Agents/chemical synthesis/chemistry/pharmacology ; Binding Sites ; Biofilms/drug effects ; Candida albicans/drug effects/*metabolism/physiology ; Cell Line ; Cell Survival/drug effects ; Ergosterol/*antagonists & inhibitors/biosynthesis ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Humans ; Hydrazines/chemical synthesis/*chemistry/pharmacology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Protein Structure, Tertiary ; Pyrazoles/*chemistry ; Structure-Activity Relationship ; }, abstract = {Literature reports suggest that pyrazoles and hydrazides are potential antimicrobial pharmocophores. Considering this fact, a series of nineteen conjugates containing hybrids of bis-pyrazole scaffolds joined through a hydrazide linker were synthesized and further evaluated for their antimicrobial activity against a panel of Gram-positive and Gram-negative bacteria along with Candida albicansMTCC 3017 strain. Although the derivatives exhibited good antibacterial activity, some of the derivatives (13d, 13j, 13l, 13p, and 13r) showed excellent anti-Candida activity with MICs values of 3.9 μg/ml, which was equipotent to that of the standard Miconazole (3.9 μg/ml), which has inspired us to further explore their anti-Candida activity. The same compounds were also tested for anti-biofilm studies against various Candida strains and among them, compounds 13l and 13r efficiently inhibited the formation of fungal biofilms. Field emission scanning electron micrographs revealed that one of the promising compound 13r showed cell damage and in turn cell death of the Candida strain. These potential conjugates (13l and 13r) also demonstrated promising ergosterol biosynthesis inhibition against some of the strains C. albicans, which were further validated through molecular docking studies. In silico computational studies were carried out to predict the binding modes and pharmacokinetic parameters of these conjugates.}, } @article {pmid30802983, year = {2019}, author = {Ledwoch, K and Said, J and Norville, P and Maillard, JY}, title = {Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {329-336}, doi = {10.1111/lam.13143}, pmid = {30802983}, issn = {1472-765X}, support = {//GAMA Healthcare though Cardiff University/ ; }, mesh = {Biofilms/*growth & development ; Disinfectants/*pharmacology ; Disinfection/*methods ; Organic Chemicals ; Sodium Hypochlorite/*pharmacology ; Staphylococcus aureus/*growth & development ; }, abstract = {Dry surface biofilms (DSB) harbouring pathogens are widespread in healthcare settings, are difficult to detect and are resistant to cleaning and disinfection interventions. Here, we describe a practical test protocol to palliate the lack of standard efficacy test methods for DSB. Staphylococcus aureus DSB were produced over a 12-day period, grown with or without the presence of organic matter, and their composition and viability were evaluated. Disinfectant treatment was conducted with a modified ASTM2967-15 test and reduction in viability, transferability and biofilm regrowth post-treatment were measured. Dry surface biofilms produced over a 12-day period had a similar carbohydrates, proteins and DNA content, regardless of the presence or absence of organic matter. The combination of sodium hypochlorite (1000 ppm) and a microfiber cloth was only effective against DSB in the absence of organic load. With the increasing concerns of the uncontrolled presence of DSB in healthcare settings, the development of effective intervention model in the presence of organic load is appropriate for the testing of biocidal products, while the use of three parameters, log10 reduction, transferability and regrowth, provides an accurate and practical measurement of product efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The widespread presence of biofilms on dry surfaces in healthcare settings has been recently documented. These dry surface biofilms (DSB) present an unprecedented challenge to cleaning and disinfection processes. Here, we describe a practical efficacy protocol based on an in vitro Staphylococcus aureus DSB model. The protocol measures reduction in viability, transferability and biofilm regrowth post-treatment to provide altogether a practical assessment of product efficacy against dry surface biofilms.}, } @article {pmid30802400, year = {2017}, author = {Tsarev, VN and Podporin, MS and Ippolitov, EV}, title = {[The application of scanning electronic microscopy and bio-reactor for evaluating eradication of microbial bio-film of root channels under endodontic treatment.].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {62}, number = {8}, pages = {506-512}, doi = {10.18821/0869-2084-2017-62-8-506-512}, pmid = {30802400}, issn = {0869-2084}, mesh = {*Biofilms ; *Disinfection ; Humans ; *Microscopy, Electron, Scanning ; *Root Canal Preparation ; Root Canal Therapy ; *Ultrasonic Therapy ; }, abstract = {According to the results of endodontic treatment of chronic forms of odontotis and periodontitis the rate of complications continues to be high - from 32% to 50% that os related to characteristics of microbial bio-film. The studies of this object in root canals and methods of eradication of bio-films are at their initial stage. The purpose of study is to provide a laboratory substantiation and evaluation of efficacy of complex effect of ultrasound processing and photo-activating disinfection of root of tooth in case of chronic forms of odontotis and periodontitis and also evaluation of endodontic treatment using scanning electronic microscopy. The micro-flora of root canals was examined using bacteriological method (4 bacterial and 2 fungous clinical isolates). The effect of ultrasound processing in complex with the system, photo-activating disinfection on micro-flora of root canal was evaluated using a bio-reactor. The analysis of bio-films of system of root canals of tooth in patients with chronic forms of odontotis (52 patients) and periodontitis (16 patients) are implemented using scanning electronic microscopy. The established availability of abundant microbial bio-film in orifices of dentinal tubules and obturation of dentinal tubules in particular cases. The features of formation of curves of growth of population of bacteria of oral micro-flora (Porphyromonas gingivalis; Fusobacterium nucleatum; Streptococcus sanguinis; Streptococcus mutans; Candida albicans; Candida krusei) as a result of complex effect of photo-dynamic activation and ultrasound as compared with control without such. The complex effect inhibits growth of microbial populations of oral bacteria and fungi species Candida.}, } @article {pmid30801748, year = {2019}, author = {Kim, HW and Chung, DH and Kim, SA and Rhee, MS}, title = {Synergistic cranberry juice combinations with natural-borne antimicrobials for the eradication of uropathogenic Escherichia coli biofilm within a short time.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {321-328}, doi = {10.1111/lam.13140}, pmid = {30801748}, issn = {1472-765X}, support = {NRF-2016R1A2B2012743//National Research Foundation of Korea/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Caprylates/*pharmacology ; Escherichia coli Infections/drug therapy ; Fruit and Vegetable Juices ; Humans ; Microscopy, Confocal ; Oils, Volatile/pharmacology ; Plant Preparations/*pharmacology ; Thymol/*pharmacology ; Urinary Tract Infections/drug therapy/microbiology ; Uropathogenic Escherichia coli/*drug effects ; Vaccinium macrocarpon/chemistry ; }, abstract = {Urinary tract infections (UTI), one of the most common diseases in humans, are caused primarily by uropathogenic Escherichia coli (UPEC). Cranberry juice (CB) is a widely known prophylaxis for UTI, but the treatment of CB alone could not effectively eradicate preformed UPEC biofilms. The aim of this study was to develop enforced CB composites within a short time by adding a small quantity of natural borne antimicrobials. UPEC biofilms (initial: 6·0 log CFU per cm[2]), formed on silicone coupons in artificial urine medium, were exposed to CB (4-8%), caprylic acid (CAR; 0·025-0·05%) and thymol (TM; 0·025-0·05%) at 37°C for 1 min. Individual treatment of each compound did not show the significant antibacterial effect on UPEC biofilms (P > 0·05). Otherwise, the survivor counts of biofilms were synergistically reduced with CB containing any of the antimicrobials. For example combined treatment with CB (8%) + CAR (0·05%) + TM (0·05%) resulted in a 6 log reduction in UPEC populations in the biofilm (no detectable bacteria remained) with 4·6 log of synergistic bactericidal effect. The confocal laser scanning microscope images indicated that any composites including TM might result in biofilm detachment from the surface. The present method is cost-effective and more acceptable to consumers as it is based on the synergistic interaction of natural borne antimicrobials. The results of this study could be widely applicable in the functional food, medical and healthcare field. SIGNIFICANCE AND IMPACT OF THE STUDY: Anti-biofilm effect of cranberry juice (CB) has been focused mainly on inhibiting biofilm formation of uropathogenic Escherichia coli (UPEC); however, combined treatment with natural borne antimicrobials derived from coconut oil (caprylic acid) and oregano essential oil (thymol) could synergistically enhance its eradicating activity against biofilms. This study developed novel CB composites showing marked anti-biofilm effects (complete eradication of UPEC biofilms within just 1 min).}, } @article {pmid30801031, year = {2019}, author = {Chouikha, I and Sturdevant, DE and Jarrett, C and Sun, YC and Hinnebusch, BJ}, title = {Differential Gene Expression Patterns of Yersinia pestis and Yersinia pseudotuberculosis during Infection and Biofilm Formation in the Flea Digestive Tract.}, journal = {mSystems}, volume = {4}, number = {1}, pages = {}, pmid = {30801031}, issn = {2379-5077}, abstract = {Yersinia pestis, the etiologic agent of plague, emerged as a fleaborne pathogen only within the last 6,000 years. Just five simple genetic changes in the Yersinia pseudotuberculosis progenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropodborne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performed in vivo transcriptional profiling of Y. pestis, a Y. pseudotuberculosis wild-type strain (unable to form biofilm in the flea foregut), and a Y. pseudotuberculosis mutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious blood meal. Surprisingly, the Y. pseudotuberculosis mutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change the expression levels of the hms genes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. The Y. pseudotuberculosis mutant uniquely expressed much higher levels of Yersinia type VI secretion system 4 (T6SS-4) in the flea, and this locus was required for flea blockage by Y. pseudotuberculosis but not for blockage by Y. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing-related genes, transcription regulation genes, and stress response genes were evident during flea infection. IMPORTANCE Y. pestis emerged as a highly virulent, arthropod-transmitted pathogen on the basis of relatively few and discrete genetic changes from Y. pseudotuberculosis. Parallel comparisons of the in vitro and in vivo transcriptomes of Y. pestis and two Y. pseudotuberculosis variants that produce a nontransmissible infection and a transmissible infection of the flea vector, respectively, provided insights into how Y. pestis has adapted to life in its flea vector and point to evolutionary changes in the regulation of metabolic and biofilm development pathways in these two closely related species.}, } @article {pmid30800673, year = {2019}, author = {Zhou, Y and Wang, S and Zhou, X and Zou, Y and Li, M and Peng, X and Ren, B and Xu, HHK and Weir, MD and Cheng, L and Chen, Y and Han, Q}, title = {Short-Time Antibacterial Effects of Dimethylaminododecyl Methacrylate on Oral Multispecies Biofilm In Vitro.}, journal = {BioMed research international}, volume = {2019}, number = {}, pages = {6393470}, pmid = {30800673}, issn = {2314-6141}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Load/drug effects ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Dental Plaque/drug therapy/microbiology ; Methacrylates/*pharmacology ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning/methods ; Quaternary Ammonium Compounds/*pharmacology ; Streptococcus/drug effects ; }, abstract = {Quaternary ammonium compounds constitute a large group of antibacterial chemicals with a potential for inhibiting dental plaque. The aims of this study were to evaluate short-time antibacterial and regulating effects of dimethylaminododecyl methacrylate (DMADDM) on multispecies biofilm viability, reformation, and bacterial composition in vitro. DMADDM, chlorhexidine (CHX), and sodium fluoride (NaF) were chosen in the present study. Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii were used to form multispecies biofilm. Cytotoxicity assay was used to determine the optimal tested concentration. 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and resazurin test of biofilm were conducted to study the biomass changes and metabolic changes of controlled multispecies biofilm. Scanning electron microscopy (SEM) was used to observe biofilm images. TaqMan real-time polymerase chain reaction was performed to evaluate the proportion change in multispecies biofilm of different groups. Cytotoxicity assay showed that there existed a certain concentration application range for DMADDM, CHX, and NaF. MTT assay and resazurin test results showed that DMADDM and CHX groups decreased multispecies biofilm growth and metabolic activity (p < 0.05), no matter after 1 min or 5 min direct contact killing or after 24 h regrowth. The proportion of S. mutans decreased steadily in DMADDM and CHX groups after 1 min and 5 min direct contact killing and 24 h regrowth, compared to control groups. A novel DMADDM-containing solution was developed, achieving effective short-time antibacterial effects and regulation ability of biofilm formation.}, } @article {pmid30800115, year = {2019}, author = {Grassi, L and Batoni, G and Ostyn, L and Rigole, P and Van den Bossche, S and Rinaldi, AC and Maisetta, G and Esin, S and Coenye, T and Crabbé, A}, title = {The Antimicrobial Peptide lin-SB056-1 and Its Dendrimeric Derivative Prevent Pseudomonas aeruginosa Biofilm Formation in Physiologically Relevant Models of Chronic Infections.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {198}, pmid = {30800115}, issn = {1664-302X}, abstract = {Antimicrobial peptides (AMPs) are promising templates for the development of novel antibiofilm drugs. Despite the large number of studies on screening and optimization of AMPs, only a few of these evaluated the antibiofilm activity in physiologically relevant model systems. Potent in vitro activity of AMPs often does not translate into in vivo effectiveness due to the interference of the host microenvironment with peptide stability/availability. Hence, mimicking the complex environment found in biofilm-associated infections is essential to predict the clinical potential of novel AMP-based antimicrobials. In the present study, we examined the antibiofilm activity of the semi-synthetic peptide lin-SB056-1 and its dendrimeric derivative (lin-SB056-1)2-K against Pseudomonas aeruginosa in an in vivo-like three-dimensional (3-D) lung epithelial cell model and an in vitro wound model (consisting of an artificial dermis and blood components at physiological levels). Although moderately active when tested alone, lin-SB056-1 was effective in reducing P. aeruginosa biofilm formation in association with 3-D lung epithelial cells in combination with the chelating agent EDTA. The dimeric derivative (lin-SB056-1)2-K demonstrated an enhanced biofilm-inhibitory activity as compared to both lin-SB056-1 and the lin-SB056-1/EDTA combination, reducing the number of biofilm-associated bacteria up to 3-Log units at concentrations causing less than 20% cell death. Biofilm inhibition by (lin-SB056-1)2-K was reported both for the reference strain PAO1 and cystic fibrosis lung isolates of P. aeruginosa. In addition, using fluorescence microscopy, a significant decrease in biofilm-like structures associated with 3-D cells was observed after peptide exposure. Interestingly, effectiveness of (lin-SB056-1)2-K was also demonstrated in the wound model with a reduction of up to 1-Log unit in biofilm formation by P. aeruginosa PAO1 and wound isolates. Overall, combination treatment and peptide dendrimerization emerged as promising strategies to improve the efficacy of AMPs, especially under challenging host-mimicking conditions. Furthermore, the results of the present study underlined the importance of evaluating the biological properties of novel AMPs in in vivo-like model systems representative of specific infectious sites in order to make a more realistic prediction of their therapeutic success, and avoid the inclusion of unpromising peptides in animal studies and clinical trials.}, } @article {pmid30799091, year = {2019}, author = {Alves-Barroco, C and Roma-Rodrigues, C and Balasubramanian, N and Guimarães, MA and Ferreira-Carvalho, BT and Muthukumaran, J and Nunes, D and Fortunato, E and Martins, R and Santos-Silva, T and Figueiredo, AMS and Fernandes, AR and Santos-Sanches, I}, title = {Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae.}, journal = {International journal of medical microbiology : IJMM}, volume = {309}, number = {3-4}, pages = {169-181}, doi = {10.1016/j.ijmm.2019.02.001}, pmid = {30799091}, issn = {1618-0607}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/pharmacology ; Bacterial Proteins/*antagonists & inhibitors/chemistry/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Extracellular Polymeric Substance Matrix/chemistry/metabolism/ultrastructure ; Female ; Flavonoids/chemistry/pharmacology ; Flavonols ; Gene Expression ; Gene Expression Regulation, Bacterial ; Molecular Docking Simulation ; Molecular Structure ; Protein Binding ; Protein Conformation ; Streptococcal Infections/microbiology ; Streptococcus/drug effects/genetics/metabolism/*physiology ; }, abstract = {Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess the presence of biofilm regulatory protein BrpA homolog in the biofilm producers; and to predict a structural model of BrpA-like protein and its binding to putative inhibitors. Our results show that SDSD isolates form biofilms on abiotic surface such as glass (hydrophilic) and polystyrene (hydrophobic), with the strongest biofilm formation observed in glass. This ability was mainly associated with a proteinaceous extracellular matrix, confirmed by the dispersion of the biofilms after proteinase K and trypsin treatment. The biofilm formation in SDSD isolates was also confirmed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Under SEM observation, VSD16 isolate formed cell aggregates during biofilm growth while VSD9 and VSD10 formed smooth and filmy layers. We show that brpA-like gene is present and expressed in SDSD biofilm-producing isolates and its expression levels correlated with the biofilm production capability, being more expressed in the late exponential phase of planktonic growth compared to biofilm growth. Fisetin, a known biofilm inhibitor and a putative BrpA binding molecule, dramatically inhibited biofilm formation by the SDSD isolates but did not affect planktonic growth, at the tested concentrations. Homology modeling was used to predict the 3D structure of BrpA-like protein. Using high throughput virtual screening and molecular docking, we selected five ligand molecules with strong binding affinity to the hydrophobic cleft of the protein, making them potential inhibitor candidates of the SDSD BrpA-like protein. These results warrant further investigations for developing novel strategies for SDSD anti-biofilm therapy.}, } @article {pmid30798554, year = {2019}, author = {Naudin, B and Heins, A and Pinhal, S and Dé, E and Nicol, M}, title = {BioFlux™ 200 Microfluidic System to Study A. baumannii Biofilm Formation in a Dynamic Mode of Growth.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1946}, number = {}, pages = {167-176}, doi = {10.1007/978-1-4939-9118-1_16}, pmid = {30798554}, issn = {1940-6029}, mesh = {Acinetobacter baumannii/drug effects/*physiology ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Microbial Sensitivity Tests ; *Microfluidic Analytical Techniques ; *Microfluidics/instrumentation/methods ; Time-Lapse Imaging ; }, abstract = {The ability of A. baumannii to develop biofilms on a wide range of surfaces can be associated to its persistence in hospital settings and the emergence of recalcitrant and chronic infections. Few compounds are available to eradicate A. baumannii biofilms, and most of them have been tested for their antibiofilm properties in static conditions. Microfluidics systems as BioFlux™ system are now available for studying A. baumannii biofilm formation in dynamic conditions. Here, we described the use of this system for studying the biofilm development of the reference strain A. baumannii ATCC 17978 in a dynamic mode. We showed how to test the activity of an antibiotic (colistin at the MIC concentration, 0.5 μg/mL) in these conditions of growth.}, } @article {pmid30798553, year = {2019}, author = {Biswas, I and Mettlach, J}, title = {A Simple Static Biofilm Assay for Acinetobacter baumannii.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1946}, number = {}, pages = {159-165}, doi = {10.1007/978-1-4939-9118-1_15}, pmid = {30798553}, issn = {1940-6029}, support = {P20 GM113117/GM/NIGMS NIH HHS/United States ; }, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*physiology ; Bacteriological Techniques ; Biofilms/*growth & development ; Humans ; }, abstract = {Acinetobacter baumannii and other Acinetobacter spp. display biofilm formation on abiotic surfaces. The degree of biofilm formation varies considerably depending on the isolates. While culturing, bacteria tend to attach to abiotic surfaces, and some surfaces perform better than others. Numerous methods are available to study in vitro biofilm formation by bacteria under static growth, and they basically rely upon culturing the bacteria in an ampule followed by staining the bacterial growth attached to the abiotic surface with a suitable dye such as crystal violet to visualize the biofilm. Subsequently, the dye is eluted with a suitable solvent, and optical density is measured to quantify the attached bacterial mass. In this chapter, we provide a basic and simple yet a powerful method to study biofilm formation by A. baumannii grown under static conditions.}, } @article {pmid30798544, year = {2019}, author = {Ravi, NS and Aslam, RF and Veeraraghavan, B}, title = {A New Method for Determination of Minimum Biofilm Eradication Concentration for Accurate Antimicrobial Therapy.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1946}, number = {}, pages = {61-67}, doi = {10.1007/978-1-4939-9118-1_6}, pmid = {30798544}, issn = {1940-6029}, mesh = {Acinetobacter baumannii/drug effects/growth & development ; Anti-Infective Agents/*pharmacology/therapeutic use ; Bacterial Load ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Humans ; *Microbial Sensitivity Tests/methods ; }, abstract = {Antimicrobial susceptibility testing (AST) is an important technique to find the susceptibility pattern of clinical isolates in order to administer the appropriate drug. One such technique is minimum inhibitory concentration (MIC), which not only identifies the right drug but also suggests the appropriate concentration necessary to neutralize the organisms in planktonic form. MIC can vary in case of adherent organisms since they form biofilms and activate survival mechanisms like quorum sensing. Here we have strategized a new method which used an inoculator plate, a resazurin dye, and a standard plate to identify minimum biofilm eradication concentration (MBEC) of adherent organisms.}, } @article {pmid30798240, year = {2019}, author = {Rajeev, M and Sushmitha, TJ and Toleti, SR and Pandian, SK}, title = {Culture dependent and independent analysis and appraisal of early stage biofilm-forming bacterial community composition in the Southern coastal seawater of India.}, journal = {The Science of the total environment}, volume = {666}, number = {}, pages = {308-320}, doi = {10.1016/j.scitotenv.2019.02.171}, pmid = {30798240}, issn = {1879-1026}, mesh = {Bacteria/*classification ; *Bacterial Physiological Phenomena ; *Biofilms ; Denaturing Gradient Gel Electrophoresis ; India ; Indian Ocean ; Microbiota ; Plankton/classification ; Seawater/*microbiology ; }, abstract = {Microbial aggregation on artificial surfaces is a fundamental phenomenon in aquatic systems that lead to biofouling, corrosion and influence the buoyancy of plastic materials. Despite the maritime activities and with nearshore large industrial sector, Laccadive Sea in the Indian Ocean has rarely been investigated for characterizing early biofilm-forming bacterial community. The present investigation was aimed to catalogue the primary colonizers on artificial surfaces and their comparison with planktonic community in southern coastal seawater of India. Surface seawater samples and biofilm assembled on three artificial surfaces over a period of 72 h of immersion in the intake area of a nuclear power plant at Kudankulam, India were collected. The structure of surface assemblages and plankton were unveiled by employing culture dependent, DGGE and NGS methods. In static condition, a collection of aerobic heterotrophic bacteria was screened in vitro for their ability to form potent biofilm. Proteobacteria preponderated the communities both in seawater and natural biofilm and Gammaproteobacteria accounted for >85% in the latter. Vibrionaceae, Alteromonadaceae and Pseudoalteromonadaceae dominated the biofilm community and constituted for 41, 25 and 8%, respectively. In contrast to other studies that showed Rhodobacteraceae family of Alphaproteobacteria as predominant component, we found Vibrionaceae of Gammaproteobacteria as dominant group in early stage of biofilm formation. Both DGGE and NGS data indicated that the attached community is noticeably distinct from those suspended in water column and form the basis for the proposed hypothesis of species sorting theory, that is, the local environmental conditions influence bacterial community assembly. Collectively, the data are testament for species sorting process that occur during initial assembly of bacterial community in marine environment and shed light on the structure of marine bacterial biofilm development. The outcome of the present study is of immense importance for designing long-term, efficient and appropriate strategies to control the biofouling phenomenon.}, } @article {pmid30797019, year = {2019}, author = {Hadpanus, P and Permsirivisarn, P and Roytrakul, S and Tungpradabkul, S}, title = {Biomarker discovery in the biofilm-forming process of Burkholderia pseudomallei by mass-spectrometry.}, journal = {Journal of microbiological methods}, volume = {159}, number = {}, pages = {26-33}, doi = {10.1016/j.mimet.2019.02.011}, pmid = {30797019}, issn = {1872-8359}, mesh = {Bacterial Proteins/chemistry/genetics/metabolism ; *Biofilms ; Biomarkers/*chemistry/metabolism ; Burkholderia pseudomallei/*chemistry/genetics/isolation & purification/physiology ; Glycogen Debranching Enzyme System/chemistry/genetics/metabolism ; Humans ; Melioidosis/*microbiology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/*methods ; }, abstract = {A serious human infectious disease called Melioidosis is a result of Burkholderia pseudomallei infection. Treatment for infected individuals is difficult due to a wide range of ineffective antibiotics including a high level of antibiotic tolerance which has been known to be caused by biofilm production. However, biofilm forming processes of this bacterium are not well documented despite multiple-methodologies being applied. In this study, we utilized a proteomics strategy called whole cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (whole cell MALDI-TOF MS) to discover a potential biomarker relating biofilm forming in B. pseudomallei. The results presented a novel specific type of enzyme amylo-alpha-1, 6-glucosidase, which was demonstrated by a higher level of gene expression during the biofilm development. Our results also suggested a list of candidate markers that might be involved in this scenario. Eventually, this knowledge may expand valuable data to the biofilm study that may increase effective treatments for people infected with B. pseudomallei and possibly other antibiotic tolerant bacteria.}, } @article {pmid30796889, year = {2019}, author = {Dong, G and Li, J and Chen, L and Bi, W and Zhang, X and Liu, H and Zhi, X and Zhou, T and Cao, J}, title = {Effects of sub-minimum inhibitory concentrations of ciprofloxacin on biofilm formation and virulence factors of Escherichia coli.}, journal = {The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases}, volume = {23}, number = {1}, pages = {15-21}, pmid = {30796889}, issn = {1678-4391}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Escherichia coli/*drug effects/*genetics ; Gene Expression/drug effects ; Gentian Violet ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Reference Values ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors ; *Virulence Factors ; }, abstract = {OBJECTIVE: To evaluate the influence of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on biofilm formation and virulence factors of Escherichia coli clinical isolates.

METHODS: Sub-MICs of CIP were determined using growth curve experiments. The biofilm-forming capacity of E. coli clinical isolates and E. coli ATCC 25922 treated or untreated with sub-MICs of CIP was assessed using a crystal violet staining assay. The biofilm structure of E. coli isolate was assessed with scanning electron microscopy (SEM). The expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were measured using quantification RT-PCR (qRT-PCR) in E. coli isolates and E. coli ATCC 25922.

RESULTS: Based on our results, the sub-MICs of CIP were 1/4 MICs. Sub-MICs of CIP significantly inhibited biofilm formation of E. coli clinical isolates and E. coli ATCC 25922 (p<0.01). SEM analyses indicated that the biofilm structure of the E. coli changed significantly after treatment with sub-MICs of CIP. Expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were also suppressed.

CONCLUSIONS: The results revealed that treatment with sub-MICs of CIP for 24h inhibited biofilm formation and reduced the expression of virulence genes and biofilm formation genes in E. coli.}, } @article {pmid30796331, year = {2019}, author = {Craft, KM and Townsend, SD}, title = {1-Amino-2'-fucosyllactose inhibits biofilm formation by Streptococcus agalactiae.}, journal = {The Journal of antibiotics}, volume = {72}, number = {6}, pages = {507-512}, doi = {10.1038/s41429-019-0151-6}, pmid = {30796331}, issn = {1881-1469}, support = {T32 GM065086/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Carbohydrate Conformation ; Oligosaccharides/*chemical synthesis/chemistry/*pharmacology ; Streptococcus agalactiae/*drug effects/physiology ; Structure-Activity Relationship ; }, abstract = {2'-Fucosyllactose (2'-FL) is a ubiquitous oligosaccharide in human milk. Importantly, this carbohydrate promotes the growth of several strains of Bifidobacteria, a class of beneficial gut commensal, and inhibits epithelial binding of pathogens. In light of these protective effects, we elected to evaluate the potential of 2'-FL to serve as an antibacterial agent against Group B Streptococcus (GBS). While 2'-FL was devoid of any substantial antimicrobial or antibiofilm activity, conversion of 2'-FL to its reducing end β-amine provided a novel antibiofilm compound.}, } @article {pmid30796312, year = {2019}, author = {Tan, A and Li, WS and Verderosa, AD and Blakeway, LV and D Mubaiwa, T and Totsika, M and Seib, KL}, title = {Moraxella catarrhalis NucM is an entry nuclease involved in extracellular DNA and RNA degradation, cell competence and biofilm scaffolding.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {2579}, pmid = {30796312}, issn = {2045-2322}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/genetics/*metabolism ; Deoxyribonucleases/genetics/*metabolism ; Gene Deletion ; Moraxella catarrhalis/*physiology ; *RNA Stability ; RNA, Bacterial/genetics/*metabolism ; }, abstract = {Moraxella catarrhalis is a host-adapted bacterial pathogen that causes otitis media and exacerbations of chronic obstructive pulmonary disease. This study characterises the conserved M. catarrhalis extracellular nuclease, a member of the ββα metal finger family of nucleases, that we have named NucM. NucM shares conserved sequence motifs from the ββα nuclease family, including the DRGH catalytic core and Mg[2+] co-ordination site, but otherwise shares little primary sequence identity with other family members, such as the Serratia Nuc and pneumococcal EndA nucleases. NucM is secreted from the cell and digests linear and circular nucleic acid. However, it appears that a proportion of NucM is also associated with the cell membrane and acts as an entry nuclease, facilitating transformation of M. catarrhalis cells. This is the first example of a ββα nuclease in a Gram negative bacteria that acts as an entry nuclease. In addition to its role in competence, NucM affects cell aggregation and biofilm formation by M. catarrhalis, with ΔnucM mutants having increased biofilm biomass. NucM is likely to increase the ability of cells to survive and persist in vivo, increasing the virulence of M. catarrhalis and potentially affecting the behaviour of other pathogens that co-colonise the otorhinolaryngological niche.}, } @article {pmid30794235, year = {2019}, author = {Stinner, DJ}, title = {CORR Insights®: Does Suture Type Influence Bacterial Retention and Biofilm Formation After Irrigation in a Mouse Model?.}, journal = {Clinical orthopaedics and related research}, volume = {477}, number = {1}, pages = {127-129}, pmid = {30794235}, issn = {1528-1132}, mesh = {Animals ; Bacteria ; *Biofilms ; Mice ; *Sutures ; }, } @article {pmid30794234, year = {2019}, author = {Markel, DC and Bergum, C and Wu, B and Bou-Akl, T and Ren, W}, title = {Does Suture Type Influence Bacterial Retention and Biofilm Formation After Irrigation in a Mouse Model?.}, journal = {Clinical orthopaedics and related research}, volume = {477}, number = {1}, pages = {116-126}, pmid = {30794234}, issn = {1528-1132}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Disease Models, Animal ; Equipment Design ; Female ; Mice, Inbred C57BL ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Staphylococcal Infections/diagnosis/microbiology/*therapy ; Staphylococcus aureus/*growth & development/ultrastructure ; Surgical Wound Infection/diagnosis/microbiology/*therapy ; Suture Techniques/*adverse effects/*instrumentation ; Sutures/*microbiology ; *Therapeutic Irrigation ; Time Factors ; }, abstract = {BACKGROUND: Irrigation and débridement are frequently utilized in the management of surgical infections, but even with aggressive débridement, it is difficult to remove all the suture material from the tissues and retained suture material may harbor bacteria and/or biofilm. The degree to which barbed or braided sutures may differentially influence the risk of infection has not been defined in a well-controlled animal model.

QUESTIONS/PURPOSES: We compared braided and barbed monofilament sutures after irrigation of an infected mouse air pouch model to determine whether the suture type influenced the effectiveness of the irrigation. After irrigation of infected pouches, sutures were compared for (1) bacterial adherence and bacterial retention; (2) qualitative and quantitative pouch thickness and cellular density; and (3) quantitative biofilm formation.

METHODS: Soft tissue air pouches were created on the backs of 60 female, mature 10-week-old BALB/cJ mice by sequentially introducing air into the subcutaneous tissue and allowing the pouch to mature. The pouches were inoculated with Staphylococcus aureus and braided or barbed monofilament sutures were implanted. Pouch irrigation was performed Day 7 after suture implantation. Suture segments were collected before and after irrigation. After euthanasia on Day 14, pouch tissues with residual suture segments were collected for analysis: microbiologic analysis done using optical density as a measure of the concentration of bacteria in the culture (the larger concentration indicates higher number of bacteria) and histologic evaluation of the pouch tissues were semiquantitative, whereas environmental scanning electron microscopy (ESEM) and confocal analyses of the biofilm and bacteria on the sutures were qualitative.

RESULTS: Histologic evaluation of pouch tissue showed all groups had inflammatory responses. Quantitatively microbiology showed no difference in bacterial number calculated from the optical density (OD) values between the two suture materials at any time point in the irrigation group. In the no-irrigation group, for the Day 7 time point, mean (± SD) OD was greater in the barbed than the OD in the braided sutures (0.52 ± 0.12 versus 0.37 ± 0.16, mean difference 0.43 [95% confidence interval, 0.08-0.13]; p = 0.007). Qualitatively, ESEM showed more bacterial retention by braided sutures before and after irrigation. Confocal imaging of the sutures demonstrated penetration of biofilm into the interstices of braided sutures and less adhesion in barbed monofilament sutures. The quantification of the biomass showed no differences between groups at all time points (before-irrigation biomass was 11.2 ± 9.3 for braided versus 5.2 ± 4.7 for barbed sutures, p = 0.196; and after-irrigation biomass was 7.2 ± 7.5 for braided versus 3.3 ± 4.3 for barbed suture, p = 0.259).

CONCLUSIONS: All sutures can retain bacteria and biofilm, but it is rarely possible to remove all suture material at the time of irrigation to treat infection. After an irrigation procedure, qualitatively braided sutures appeared to harbor more bacteria and to retain more biofilm than barbed monofilaments.

CLINICAL RELEVANCE: When saline irrigation was used to simulate infection treatment in an infected mouse air pouch model, bacteria/biofilm was not completely eliminated from either braided or barbed monofilament sutures. The irrigation appeared to clear more bacteria and biofilm from the monofilament despite having barbs. Unfortunately, current technologies do not allow direct quantitative comparisons of biofilm retention. Clinicians should be aware that in the face of infection, any retained sutures may harbor bacteria despite irrigation.}, } @article {pmid30794029, year = {2019}, author = {Mitra, S and Chayani, N and Mohapatra, D and Barik, MR and Sharma, S and Basu, S}, title = {High Prevalence of Biofilm-Forming MRSA in the Conjunctival Flora in Chronic Dacryocystitis.}, journal = {Seminars in ophthalmology}, volume = {34}, number = {2}, pages = {74-79}, doi = {10.1080/08820538.2019.1578382}, pmid = {30794029}, issn = {1744-5205}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Case-Control Studies ; Chronic Disease ; Conjunctiva/*microbiology ; DNA, Bacterial/*genetics ; Dacryocystitis/drug therapy/*epidemiology/microbiology ; Eye Infections, Bacterial/*epidemiology/microbiology ; Follow-Up Studies ; Humans ; India/epidemiology ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/isolation & purification ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Prevalence ; Prospective Studies ; Staphylococcal Infections/drug therapy/*epidemiology/microbiology ; }, abstract = {OBJECTIVES: To report the microbiological spectrum of conjunctival flora and prevalence of biofilm-forming Methicillin-resistant Staphylococcus aureus (MRSA) in conjunctival flora in chronic dacryocystitis.

DESIGN: Prospective, case-control study.

METHODS: We included patients with unilateral chronic dacryocystitis, and their unaffected eyes as control. Microbiological profile and antibiotic susceptibility of the isolates was determined by standard microbiological procedures. S. aureus isolates were further evaluated for Methicillin resistance by Oxacillin resistance screening agar method and mecA polymerase chain reaction (PCR) and for biofilm synthesis by Congo red agar method, Microtitre plate (MTP) assay, and ica A and ica D PCR.

RESULTS: We found 95 patients with unilateral chronic dacryocystitis. Aerobic Gram-positive isolates (74.2%, n = 72) were more than Gram-negative (25.7%, n = 25) or anaerobic isolates (20.5%, n = 25). S. aureus was most common (46.4%, n = 45), followed by Pseudomonas aeruginosa (10.3%, n = 10). Gram-positive isolates showed highest sensitivity to Linezolid (100%) and higher generation fluoroquinolones. Gram-negative isolates showed good sensitivity (>90%) to all tested antibiotics. S. aureus isolates showed MRSA prevalence as 93.5% and 96.9% by Oxacillin resistance screening agar method and mecA PCR, respectively. Biofilm formation was found in 71.8% MRSA isolates by MTP assay and 58.1% MRSA isolates were resistant to ≥3 classes of antibiotics.

CONCLUSIONS: Gram-positive organisms, specifically S. aureus, are the major etiological agent in chronic dacryocystitis. There is high prevalence of MRSA in these isolates and concurrent biofilm formation.}, } @article {pmid30792088, year = {2019}, author = {Vyas, N and Manmi, K and Wang, Q and Jadhav, AJ and Barigou, M and Sammons, RL and Kuehne, SA and Walmsley, AD}, title = {Which Parameters Affect Biofilm Removal with Acoustic Cavitation? A Review.}, journal = {Ultrasound in medicine & biology}, volume = {45}, number = {5}, pages = {1044-1055}, doi = {10.1016/j.ultrasmedbio.2019.01.002}, pmid = {30792088}, issn = {1879-291X}, mesh = {Acoustics ; Biocompatible Materials ; Biofilms/*growth & development ; Dental Implants/*microbiology ; Microscopy, Electron, Scanning ; Surface Properties ; *Ultrasonic Waves ; }, abstract = {Bacterial biofilms are a cause of contamination in a wide range of medical and biological areas. Ultrasound is a mechanical energy that can remove these biofilms using cavitation and acoustic streaming, which generate shear forces to disrupt biofilm from a surface. The aim of this narrative review is to investigate the literature on the mechanical removal of biofilm using acoustic cavitation to identify the different operating parameters affecting its removal using this method. The properties of the liquid and the properties of the ultrasound have a large impact on the type of cavitation generated. These include gas content, temperature, surface tension, frequency of ultrasound and acoustic pressure. For many of these parameters, more research is required to understand their mechanisms in the area of ultrasonic biofilm removal, and further research will help to optimise this method for effective removal of biofilms from different surfaces.}, } @article {pmid30791514, year = {2019}, author = {Wallis, JK and Krömker, V and Paduch, JH}, title = {Biofilm Challenge: Lactic Acid Bacteria Isolated from Bovine Udders versus Staphylococci.}, journal = {Foods (Basel, Switzerland)}, volume = {8}, number = {2}, pages = {}, pmid = {30791514}, issn = {2304-8158}, support = {Project 31833//Deutsche Bundesstiftung Umwelt/ ; 1803//Steinbeis Research Center Milk Science/ ; }, abstract = {Mastitis poses a considerable threat to productivity and to animal welfare on modern dairy farms. However, the common way of antibiotic treatment does not always lead to a cure. Unsuccessful cures can, among other reasons, occur due to biofilm formation of the causative agent. This has attracted interest from researchers to introduce promising alternative therapeutic approaches, such as the use of beneficial lactic acid bacteria (LAB). In fact, using LAB for treating mastitis probably requires the formation of a beneficial biofilm by the probiotic bacteria. The present study investigated the ability of five LAB strains, selected on the basis of results from previous studies, to remove and to replace pathogenic biofilms in vitro. For this purpose, Staphylococcus (S.) aureus ATCC 12,600 and two strains-S. xylosus (35/07) and S. epidermidis (575/08)-belonging to the group of coagulase negative staphylococci (CNS) were allowed to form biofilms in a 96-well plate. Subsequently, the LAB were added to the well. The biofilm challenge was evaluated by scraping off and suspending the biofilm cells, followed by a plate count of serial dilutions using selective media. All the LAB strains successfully removed the staphylococcal biofilms. However, only Lactobacillus (L.) rhamnosus ATCC 7469 and L. plantarum 2/37 formed biofilms of their own to replace the pathogenic ones.}, } @article {pmid30787924, year = {2019}, author = {Sivakumar, K and Scarascia, G and Zaouri, N and Wang, T and Kaksonen, AH and Hong, PY}, title = {Salinity-Mediated Increment in Sulfate Reduction, Biofilm Formation, and Quorum Sensing: A Potential Connection Between Quorum Sensing and Sulfate Reduction?.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {188}, pmid = {30787924}, issn = {1664-302X}, abstract = {Biocorrosion in marine environment is often associated with biofilms of sulfate reducing bacteria (SRB). However, not much information is available on the mechanism underlying exacerbated rates of SRB-mediated biocorrosion under saline conditions. Using Desulfovibrio (D.) vulgaris and Desulfobacterium (Db.) corrodens as model SRBs, the enhancement effects of salinity on sulfate reduction, N-acyl homoserine lactone (AHL) production and biofilm formation by SRBs were demonstrated. Under saline conditions, D. vulgaris and Db. corrodens exhibited significantly higher specific sulfate reduction and specific AHL production rates as well as elevated rates of biofilm formation compared to freshwater medium. Salinity-induced enhancement traits were also confirmed at transcript level through reverse transcription quantitative polymerase chain reaction (RT-qPCR) approach, which showed salinity-influenced increase in the expression of genes associated with carbon metabolism, sulfate reduction, biofilm formation and histidine kinase signal transduction. In addition, by deploying quorum sensing (QS) inhibitors, a potential connection between sulfate reduction and AHL production under saline conditions was demonstrated, which is most significant during early stages of sulfate metabolism. The findings collectively revealed the interconnection between QS, sulfate reduction and biofilm formation among SRBs, and implied the potential of deploying quorum quenching approaches to control SRB-based biocorrosion in saline conditions.}, } @article {pmid30786799, year = {2019}, author = {Yong, YY and Dykes, GA and Choo, WS}, title = {Biofilm formation by staphylococci in health-related environments and recent reports on their control using natural compounds.}, journal = {Critical reviews in microbiology}, volume = {45}, number = {2}, pages = {201-222}, doi = {10.1080/1040841X.2019.1573802}, pmid = {30786799}, issn = {1549-7828}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Biological Products/*pharmacology ; Humans ; Staphylococcal Infections/*microbiology ; Staphylococcus/*drug effects/genetics/isolation & purification/physiology ; }, abstract = {Staphylococci are Gram-positive bacteria that are ubiquitous in the environment and able to form biofilms on a range of surfaces. They have been associated with a range of human health issues such as medical device-related infection, localized skin infection, or direct infection caused by toxin production. The extracellular material produced by these bacteria resists antibiotics and host defence mechanism which complicates the treatment process. The commonly reported Staphylococcus species are Staphylococcus aureus and S. epidermidis as they inhabit human bodies. However, the emergence of other staphylococci, such as S. haemolyticus, S. lugdunensis, S. saprophyticus, S. capitis, S. saccharolyticus, S. warneri, S. cohnii, and S. hominis, is also of concern and they have been associated with biofilm formation. This review critically assesses recent cases on the biofilm formation by S. aureus, S. epidermidis, and other staphylococci reported in health-related environments. The control of biofilm formation by staphylococci using natural compounds is specifically discussed as they represent potential anti-biofilm agents which may reduce the burden of antibiotic resistance.}, } @article {pmid30785531, year = {2019}, author = {Fraiha, RO and Pereira, APR and Brito, EDCA and Borges, CL and Parente, AFA and Perdomo, RT and Macedo, MLR and Weber, SS}, title = {Stress conditions in the host induce persister cells and influence biofilm formation by Staphylococcus epidermidis RP62A.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {52}, number = {}, pages = {e20180001}, doi = {10.1590/0037-8682-0001-2018}, pmid = {30785531}, issn = {1678-9849}, mesh = {Biofilms/*growth & development ; Biological Assay ; Culture Media/*pharmacology ; Host Microbial Interactions/drug effects/*physiology ; Humans ; Staphylococcus epidermidis/drug effects/pathogenicity/*physiology ; Stress, Physiological ; Virulence/drug effects/*physiology ; }, abstract = {INTRODUCTION: Studies have demonstrated that pathogens react to the harsh conditions in human tissues by inducing mechanisms that promote survival.

METHODS: Persistence and biofilm-forming ability were evaluated during stress conditions that mimic those in the host.

RESULTS: Carbon-source availability had a positive effect on Staphylococcus epidermidis RP62A adhesion during hypoxia, accompanied by a decrease in pH. In contrast, iron limitation led to decreased surface-adherent biomass, accompanied by an increase medium acidification and lactate levels. Interestingly, iron starvation and hypoxia induced persister cells in planktonic culture.

CONCLUSIONS: These findings highlight the role of host stress in the virulence of S. epidermidis.}, } @article {pmid30785306, year = {2019}, author = {Lou, Z and Letsididi, KS and Yu, F and Pei, Z and Wang, H and Letsididi, R}, title = {Inhibitive Effect of Eugenol and Its Nanoemulsion on Quorum Sensing-Mediated Virulence Factors and Biofilm Formation by Pseudomonas aeruginosa.}, journal = {Journal of food protection}, volume = {82}, number = {3}, pages = {379-389}, doi = {10.4315/0362-028X.JFP-18-196}, pmid = {30785306}, issn = {1944-9097}, mesh = {Anti-Bacterial Agents ; Biofilms/*growth & development ; Eugenol/*pharmacology ; *Pseudomonas aeruginosa/physiology ; *Quorum Sensing/drug effects ; Virulence Factors/metabolism ; }, abstract = {The aim of the present study was to evaluate the quorum sensing (QS) inhibition potential of eugenol and eugenol nanoemulsion against QS-dependent virulence factor production and gene expression, as well as biofilm formation in Pseudomonas aeruginosa. In the current study, eugenol nanoemulsion at a sub-MIC of 0.2 mg/mL specifically inhibited about 50% of the QS-mediated violacein production in Chromobacterium violaceum, as well as the production of N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL) and C4-HSL N-acyl homoserine lactone signal molecules, pyocyanin, and swarming motility in P. aeruginosa. The inhibitive effect of eugenol and its nanoemulsion on the expression of the QS synthase genes was concentration dependent, displaying 65 and 52% expression level for lasI, respectively, and 61 and 45% expression level for rhlI, respectively, at a concentration of 0.2 mg/mL. In addition, the inhibitive effect of eugenol and its nanoemulsion on the expression of the rhlA gene responsible for the production of rhamnolipid was also concentration dependent, displaying 65 and 51% expression level for the rhlA gene, respectively, at a concentration of 0.2 mg/mL. Eugenol and its nanoemulsion also displayed 36 and 63% respective inhibition of biofilm formation by P. aeruginosa at the 0.2 mg/mL concentration. Therefore, the nanoemulsion could be used as a novel QS-based antibacterial and antibiofilm agent for the control of harmful bacteria.}, } @article {pmid30785206, year = {2019}, author = {Vollaro, A and Catania, MR and Iesce, MR and Sferruzza, R and D'Abrosca, B and Donnarumma, G and De Filippis, A and Cermola, F and DellaGreca, M and Buommino, E}, title = {Antimicrobial and anti-biofilm properties of novel synthetic lignan-like compounds.}, journal = {The new microbiologica}, volume = {42}, number = {1}, pages = {21-28}, pmid = {30785206}, issn = {1121-7138}, mesh = {*Anti-Infective Agents/pharmacology ; *Bacteria/drug effects ; *Biofilms/drug effects ; *Lignans/pharmacology ; Microbial Sensitivity Tests ; *Microbial Viability/drug effects ; Microscopy, Confocal ; }, abstract = {Antibiotic resistance and biofilm tolerance are among the principal factors involved in the persistence of chronic infections. The need for new antimicrobials is an ever-increasing challenge in clinical environments and in the control of global health. Arylfurans form a set of structures that have been identified in many natural products, e.g. lignans. Lignans are a sub-group of non-flavonoid polyphenols that play an active role in plants' defense against bacteria and fungi infections. The aim of this study was to identify novel synthetic arylfurans and lignan-like arylbenzylfurans exhibiting antimicrobial properties. The molecules synthetized were tested against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and S. epidermidis. We found that among tested compounds, arylbenzylfuran 11 was active against S. aureus and S. epidermidis with an MIC of 4 μg ml-1. Compound 11 was also active on methicillin-resistant S. aureus and S. epidermidis. By confocal laser scanning microscopy, we showed that 32 μg ml-1 of compound 11 was able to induce a significant reduction in S. aureus and S. epidermidis biofilms viability. Finally, we demonstrated that compound 11 was not cytotoxic on HaCat cells up to 128 μg ml-1. This work shows the antimicrobial and anti-biofilm potential of a synthetic lignan-like furan.}, } @article {pmid30784999, year = {2019}, author = {Hu, Q and Zhou, N and Rene, ER and Wu, D and Sun, D and Qiu, B}, title = {Stimulation of anaerobic biofilm development in the presence of low concentrations of toxic aromatic pollutants.}, journal = {Bioresource technology}, volume = {281}, number = {}, pages = {26-30}, doi = {10.1016/j.biortech.2019.02.076}, pmid = {30784999}, issn = {1873-2976}, mesh = {Anaerobiosis ; Bacteria/metabolism ; *Biofilms ; Sewage/microbiology ; Wastewater ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The main aim of this work was to stimulate biofilm formation in the presence of wastewater containing aromatic compounds with different toxicities (EC50). The results indicated that wastewater with an EC50 value >85% accelerates the attachment of bacteria onto the bio-carriers because the toxic wastewater stimulates the production of extracellular polymeric substances (EPS) from the seed sludge. In order to understand the role of EPS on biofilm development, experiments were conducted using the seed sludge, from which the soluble, loosely bound, and tightly bound EPS were removed. The soluble EPS fraction was determined to be crucial for biofilm development. Firmicutes bacterium and Clostridium chromoreductans survived and were enriched in the formed biofilms in our study, which can resist toxic aromatics.}, } @article {pmid30783456, year = {2019}, author = {Xu, Y and Wang, J and Hao, Z and Wang, S and Liang, C}, title = {Biodegradable ciprofloxacin-incorporated waterborne polyurethane polymers prevent bacterial biofilm formation in vitro.}, journal = {Experimental and therapeutic medicine}, volume = {17}, number = {3}, pages = {1831-1836}, pmid = {30783456}, issn = {1792-0981}, abstract = {The aim of the present study was to explore whether ciprofloxacin-incorporated waterborne polyurethane (WBPU) polymers have the capacity to inhibit bacterial biofilm formation in vitro. WBPU polymers were incorporated with ciprofloxacin and were cultured with Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) in media for 2, 4 or 7 days. In another experiment, the WBPU membranes were cultured with Proteus mirabilis (P. mirabilis) in artificial urine for 2, 4 or 7 days. Colony counting, scanning electron microscopy and fluorescence confocal microscopy were utilized to examine bacterial biofilms on the surfaces of membranes. The membranes were further co-cultured with P. mirabilis in a simple model of an artificial catheterized bladder in order to evaluate their ability to control encrustation. The WBPU films with ciprofloxacin effectively inhibited bacterial biofilm formation in the culture medium and in artificial urine. In addition, in artificial urine, the films with ciprofloxacin reduced catheter obstruction. In conclusion, ciprofloxacin-incorporated WBPU polymers are able to effectively inhibit bacterial biofilm formation in vitro.}, } @article {pmid30782633, year = {2019}, author = {Nepper, JF and Lin, YC and Weibel, DB}, title = {Rcs Phosphorelay Activation in Cardiolipin-Deficient Escherichia coli Reduces Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {201}, number = {9}, pages = {}, pmid = {30782633}, issn = {1098-5530}, mesh = {Biofilms/*growth & development ; Cardiolipins/*metabolism ; Cell Membrane/*metabolism ; Cholic Acids/metabolism ; Escherichia coli/*growth & development ; Escherichia coli Proteins/*metabolism ; Protein Transport ; *Signal Transduction ; Stress, Physiological ; }, abstract = {Biofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation in Escherichia coli cells by as much as 50%. The absence of cardiolipin activates the regulation of colanic acid synthesis (Rcs) envelope stress response, which represses the production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation in E. coli and suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.IMPORTANCE There is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation in Escherichia coli cells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.}, } @article {pmid30782630, year = {2019}, author = {Rotman, ER and Bultman, KM and Brooks, JF and Gyllborg, MC and Burgos, HL and Wollenberg, MS and Mandel, MJ}, title = {Natural Strain Variation Reveals Diverse Biofilm Regulation in Squid-Colonizing Vibrio fischeri.}, journal = {Journal of bacteriology}, volume = {201}, number = {9}, pages = {}, pmid = {30782630}, issn = {1098-5530}, support = {R35 GM119627/GM/NIGMS NIH HHS/United States ; R25 GM079300/GM/NIGMS NIH HHS/United States ; T32 GM008061/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; T32 GM008349/GM/NIGMS NIH HHS/United States ; R21 AI117262/AI/NIAID NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/classification/genetics/*growth & development ; Animals ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; *Genetic Variation ; Hawaii ; Mediterranean Sea ; Polysaccharides, Bacterial/*biosynthesis ; Signal Transduction ; *Symbiosis ; }, abstract = {The mutualistic symbiont Vibrio fischeri builds a symbiotic biofilm during colonization of squid hosts. Regulation of the exopolysaccharide component, termed Syp, has been examined in strain ES114, where production is controlled by a phosphorelay that includes the inner membrane hybrid histidine kinase RscS. Most strains that lack RscS or encode divergent RscS proteins cannot colonize a squid host unless RscS from a squid symbiont is heterologously expressed. In this study, we examine V. fischeri isolates worldwide to understand the landscape of biofilm regulation during beneficial colonization. We provide a detailed study of three distinct evolutionary groups of V. fischeri and find that while the RscS-Syp biofilm pathway is required in one of the groups, two other groups of squid symbionts require Syp independent of RscS. Mediterranean squid symbionts, including V. fischeri SR5, colonize without an RscS homolog encoded by their genome. Additionally, group A V. fischeri strains, which form a tightly related clade of Hawaii isolates, have a frameshift in rscS and do not require the gene for squid colonization or competitive fitness. These same strains have a frameshift in sypE, and we provide evidence that this group A sypE allele leads to an upregulation in biofilm activity. Thus, this work describes the central importance of Syp biofilm in colonization of diverse isolates and demonstrates that significant evolutionary transitions correspond to regulatory changes in the syp pathway.IMPORTANCE Biofilms are surface-associated, matrix-encased bacterial aggregates that exhibit enhanced protection to antimicrobial agents. Previous work has established the importance of biofilm formation by a strain of luminous Vibrio fischeri bacteria as the bacteria colonize their host, the Hawaiian bobtail squid. In this study, expansion of this work to many natural isolates revealed that biofilm genes are universally required, yet there has been a shuffling of the regulators of those genes. This work provides evidence that even when bacterial behaviors are conserved, dynamic regulation of those behaviors can underlie evolution of the host colonization phenotype. Furthermore, this work emphasizes the importance of investigating natural diversity as we seek to understand molecular mechanisms in bacteria.}, } @article {pmid30782552, year = {2019}, author = {Laureni, M and Weissbrodt, DG and Villez, K and Robin, O and de Jonge, N and Rosenthal, A and Wells, G and Nielsen, JL and Morgenroth, E and Joss, A}, title = {Biomass segregation between biofilm and flocs improves the control of nitrite-oxidizing bacteria in mainstream partial nitritation and anammox processes.}, journal = {Water research}, volume = {154}, number = {}, pages = {104-116}, doi = {10.1016/j.watres.2018.12.051}, pmid = {30782552}, issn = {1879-2448}, mesh = {Bacteria ; *Biofilms ; Biomass ; Bioreactors ; *Nitrites ; Nitrogen ; Oxidation-Reduction ; }, abstract = {The control of nitrite-oxidizing bacteria (NOB) challenges the implementation of partial nitritation and anammox (PN/A) processes under mainstream conditions. The aim of the present study was to understand how operating conditions impact microbial competition and the control of NOB in hybrid PN/A systems, where biofilm and flocs coexist. A hybrid PN/A moving-bed biofilm reactor (MBBR; also referred to as integrated fixed film activated sludge or IFAS) was operated at 15 °C on aerobically pre-treated municipal wastewater (23 mgNH4-N L[-1]). Ammonium-oxidizing bacteria (AOB) and NOB were enriched primarily in the flocs, and anammox bacteria (AMX) in the biofilm. After decreasing the dissolved oxygen concentration (DO) from 1.2 to 0.17 mgO2 L[-1] - with all other operating conditions unchanged - washout of NOB from the flocs was observed. The activity of the minor NOB fraction remaining in the biofilm was suppressed at low DO. As a result, low effluent NO3[-] concentrations (0.5 mgN L[-1]) were consistently achieved at aerobic nitrogen removal rates (80 mgN L[-1] d[-1]) comparable to those of conventional treatment plants. A simple dynamic mathematical model, assuming perfect biomass segregation with AOB and NOB in the flocs and AMX in the biofilm, was able to qualitatively reproduce the selective washout of NOB from the flocs in response to the decrease in DO-setpoint. Similarly, numerical simulations indicated that flocs removal is an effective operational strategy to achieve the selective washout of NOB. The direct competition for NO2[-] between NOB and AMX - the latter retained in the biofilm and acting as a "NO2-sink" - was identified by the model as key mechanism leading to a difference in the actual growth rates of AOB and NOB (i.e., μNOB < μAOB in flocs) and allowing for the selective NOB washout over a broad range of simulated sludge retention times (SRT = 6.8-24.5 d). Experimental results and model predictions demonstrate the increased operational flexibility, in terms of variables that can be easily controlled by operators, offered by hybrid systems as compared to solely biofilm systems for the control of NOB in mainstream PN/A applications.}, } @article {pmid30779754, year = {2019}, author = {Zhao, M and Li, W and Liu, K and Li, H and Lan, X}, title = {C4-HSL aptamers for blocking qurom sensing and inhibiting biofilm formation in Pseudomonas aeruginosa and its structure prediction and analysis.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0212041}, pmid = {30779754}, issn = {1932-6203}, mesh = {4-Butyrolactone/*analogs & derivatives/antagonists & inhibitors/chemistry ; Aptamers, Nucleotide/chemical synthesis/*chemistry/pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Drug Design ; Models, Molecular ; Nucleic Acid Conformation ; Protein Binding/drug effects ; Pseudomonas aeruginosa/drug effects/*physiology ; Quorum Sensing/drug effects ; Structure-Activity Relationship ; }, abstract = {This study aimed to screen DNA aptamers against the signal molecule C4-HSL of the rhl system for the inhibition of biofilm formation of Pseudomonas aeruginosa using an improved systematic evolution of ligand by exponential enrichment (SELEX) method based on a structure-switching fluorescent activating bead. The aptamers against the C4-HSL with a high affinity and specifity were successfully obtained and evaluated in real-time by this method. Results of biofilm inhibition experiments in vitro showed that the biofilm formation of P. aeruginosa was efficiently reduced to about 1/3 by the aptamers compared with that of the groups without the aptamers. Independent secondary structure simulation and computer-aided tertiary structure prediction (3dRNA) showed that the aptamers contained a highly conserved Y-shaped structural unit. Therefore, this study benefits the search for new methods for the detection and treatment of P. aeruginosa biofilm formation.}, } @article {pmid30779315, year = {2019}, author = {Bachtiar, BM and Srisawat, C and Bachtiar, EW}, title = {RNA aptamers selected against yeast cells inhibit Candida albicans biofilm formation in vitro.}, journal = {MicrobiologyOpen}, volume = {8}, number = {8}, pages = {e00812}, pmid = {30779315}, issn = {2045-8827}, mesh = {Antifungal Agents/isolation & purification/*metabolism ; Aptamers, Nucleotide/isolation & purification/*metabolism ; Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/*growth & development ; Colorimetry ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {Aptamers that bind live bacterial cells have been widely investigated, but their potential to inhibit Candida albicans biofilm formation needs to be further explored. The aims of this study were to evaluate the binding of C. albicans to RNA aptamers and to examine the potential of aptamers to inhibit C. albicans biofilm formation in vitro. In this study, RNA aptamers selected against yeast cells of C. albicans ATCC 10231 were developed using the systematic evolution of ligands by exponential enrichment (SELEX) technique. The binding affinity of the resulting aptamers was then determined by an aptamer-linked immobilized sorbent assay (ALISA), and a colorimetric (MTT) assay was used to measure the metabolic activity of Candida biofilms. After 11 rounds of SELEX, two candidate aptamers, Ca-apt-1 and Ca-apt-12, were identified. The Ca-apt-1 aptamer also recognized C. albicans isolated from clinical specimens but did not recognize other oral microorganisms (i.e., Streptococcus mutans and Saccharomyces cerevisiae). The ALISA results showed that the binding affinity of these aptamers was comparable to that of an anti-C. albicans monoclonal antibody. In addition, Ca-apt-1 could inhibit biofilm and hyphal formation of C. albicans in vitro, as demonstrated using biofilm assays. This study shows that RNA aptamers could potentially be used in diagnostic and therapeutic applications for C. albicans-related disease in the future.}, } @article {pmid30776636, year = {2019}, author = {Xu, G and Zheng, X and Lu, Y and Liu, G and Luo, H and Li, X and Zhang, R and Jin, S}, title = {Development of microbial community within the cathodic biofilm of single-chamber air-cathode microbial fuel cell.}, journal = {The Science of the total environment}, volume = {665}, number = {}, pages = {641-648}, doi = {10.1016/j.scitotenv.2019.02.175}, pmid = {30776636}, issn = {1879-1026}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Electrodes ; Microbiota/*physiology ; }, abstract = {The aim of this study was to investigate the development of microbial community within the cathodic biofilm of single-chamber air-cathode microbial fuel cell (MFC). To analyze microbial community structures within cathodic biofilm, cathodic biofilm samples were stratified into three layers, i.e., the cathode-side layer (0-40 μm), the middle layer (40-80 μm), and the anolyte-side layer (80-120 μm). After four starting cycles (0-188 h), the maximum power densities of the MFC fed with 1 g/L acetate decreased from 1056 ± 110 to 410 ± 50 mW/m[2] within 15 cycles (~30 d) of operation. The relative abundance of Pseudomonas gradually increased from 18.9% in the 1st cycle to 50.2% in the 4th cycle. After 15 cycles, the relative abundance of Pseudomonas became 53.8%, 16.4%, and 8.90% in the middle, anolyte-side, and cathode-side layers, respectively. The aerobic bacteria within the cathodic biofilm increased from 24% in the anodyte-side layer to 43% in the cathode-side layer. The relative abundance of Methanobrevibacter was 42.1% and 37.2% after 3 and 15 cycles, respectively. The bacterial community structures were similar among cycles 2, 3, and 4, but significantly different in the 15th cycle. The results from this study should be useful to understand the mechanism of the cathodic biofilm formation and to develop strategies to enhance performance of the MFC.}, } @article {pmid30773505, year = {2019}, author = {Prasad, M and Obana, N and Sakai, K and Nagakubo, T and Miyazaki, S and Toyofuku, M and Fattaccioli, J and Nomura, N and Utada, AS}, title = {Point Mutations Lead to Increased Levels of c-di-GMP and Phenotypic Changes to the Colony Biofilm Morphology in Alcanivorax borkumensis SK2.}, journal = {Microbes and environments}, volume = {34}, number = {1}, pages = {104-107}, pmid = {30773505}, issn = {1347-4405}, mesh = {Alcanivoraceae/genetics/metabolism/*physiology ; Alkanes/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Genome, Bacterial/genetics ; Phenotype ; Point Mutation ; Polysaccharides, Bacterial/biosynthesis ; }, abstract = {Alcanivorax borkumensis is a ubiquitous marine bacterium that utilizes alkanes as a sole carbon source. We observed two phenotypes in the A. borkumensis SK2 type strain: rough (R) and smooth (S) types. The S type exhibited lower motility and higher polysaccharide production than the R type. Full genome sequencing revealed a mutation in the S type involved in cyclic-di-GMP production. The present results suggest that higher c-di-GMP levels in the S type control the biofilm forming behavior of this bacterium in a manner commensurate with other Gram-negative bacteria.}, } @article {pmid30772604, year = {2019}, author = {Cascioferro, S and Parrino, B and Petri, GL and Cusimano, MG and Schillaci, D and Di Sarno, V and Musella, S and Giovannetti, E and Cirrincione, G and Diana, P}, title = {2,6-Disubstituted imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent staphylococcal biofilm inhibitors.}, journal = {European journal of medicinal chemistry}, volume = {167}, number = {}, pages = {200-210}, doi = {10.1016/j.ejmech.2019.02.007}, pmid = {30772604}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/*chemical synthesis/pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects/growth & development/pathogenicity ; Gram-Positive Bacteria/drug effects/growth & development/pathogenicity ; Indoles/chemical synthesis/pharmacology ; Staphylococcus/*drug effects/physiology ; Thiadiazoles/*chemical synthesis/*pharmacology ; Virulence/drug effects ; }, abstract = {A class of 36 new 2-(6-phenylimidazo[2,-1-b][1,3,4]thiadiazol-2-yl)-1H-indoles was efficiently synthesized and evaluated for their anti-biofilm properties against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923, S. aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228, and the Gram-negative strains Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ATCC 25922. Many of these new compounds, were able to inhibit biofilm formation of the tested staphylococcal strains showing BIC50 lower than 10 μg/ml. In particular, derivatives 9c and 9h showed remarkable anti-biofilm activity against S. aureus ATCC 25923 with BIC50 values of 0.5 and 0.8 μg/ml, respectively, whereas compound 9aa was the most potent against S. aureus ATCC 6538, with a BIC50 of 0.3 μg/ml. Remarkably, these compounds showed effects in the early stages of the biofilm formation without affecting the mature biofilm of the same strains and the viability of the planktonic form. Their ability in counteracting a virulence factor (biofilm formation) without interfering with the bacterial growth in the free life form make them novel valuable anti-virulence agents.}, } @article {pmid30771661, year = {2019}, author = {Yang, Y and Choi, C and Xie, G and Park, JD and Ke, S and Yu, JS and Zhou, J and Lim, B}, title = {Electron transfer interpretation of the biofilm-coated anode of a microbial fuel cell and the cathode modification effects on its power.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {127}, number = {}, pages = {94-103}, doi = {10.1016/j.bioelechem.2019.02.004}, pmid = {30771661}, issn = {1878-562X}, mesh = {Acetates/metabolism ; Bioelectric Energy Sources/*microbiology ; Biofilms/growth & development ; Carbon/chemistry ; Clostridium/enzymology/physiology ; Cytochromes c/metabolism ; Electricity ; Electrodes ; Electron Transport ; Flavin Mononucleotide/metabolism ; NAD/metabolism ; Oxidation-Reduction ; Porosity ; Proteobacteria/enzymology/physiology ; }, abstract = {Biofilm-coated electrodes and outer cell membrane-mimicked electrodes were examined to verify an extracellular electron transfer mechanism using Marcus theory for a donor-acceptor electron transfer. Redox couple-bound membrane electrodes were prepared by impregnating redox coenzymes into Nafion films on carbon cloth electrodes. The electron transfer was believed to occur sequentially from acetate to nicotinamide adenine dinucleotide (NAD), c-type cytochrome, flavin mononucleotide (FMN) (or riboflavin (RBF)) and the anode substrate. Excellent polarisation and power density characteristics were contributed by the modification of the cathode with a high-surface-area ordered mesoporous carbon or a hollow core-mesoporous shell carbon. The maximum power density of the microbial fuel cell (MFC) could be improved by a factor of two mainly due to the accelerated electron consumption by modifying the cathode surfaces within three-dimensionally interconnected mesoporous carbon particles, and the anode was coated with a mixed culture of anaerobic bacteria.}, } @article {pmid30771288, year = {2019}, author = {Perez-Lopez, MI and Mendez-Reina, R and Trier, S and Herrfurth, C and Feussner, I and Bernal, A and Forero-Shelton, M and Leidy, C}, title = {Variations in carotenoid content and acyl chain composition in exponential, stationary and biofilm states of Staphylococcus aureus, and their influence on membrane biophysical properties.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1861}, number = {5}, pages = {978-987}, doi = {10.1016/j.bbamem.2019.02.001}, pmid = {30771288}, issn = {1879-2642}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Antimicrobial Cationic Peptides/chemistry/pharmacology ; Biofilms/drug effects/*growth & development ; Carotenoids/chemistry/*metabolism ; Microbial Sensitivity Tests ; Particle Size ; Phosphatidylglycerols/chemistry/*metabolism ; Staphylococcus aureus/chemistry/drug effects/isolation & purification/*metabolism ; Surface Properties ; Temperature ; }, abstract = {Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (kc) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents.}, } @article {pmid30770577, year = {2019}, author = {Sweeney, E and Lovering, AM and Bowker, KE and MacGowan, AP and Nelson, SM}, title = {An in vitro biofilm model of Staphylococcus aureus infection of bone.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {294-302}, doi = {10.1111/lam.13131}, pmid = {30770577}, issn = {1472-765X}, support = {//North Bristol NHS Trust/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Cattle ; Daptomycin/*pharmacology ; Disease Models, Animal ; Femur/microbiology ; Gentamicins/*pharmacology ; Microbial Sensitivity Tests ; Osteomyelitis/*drug therapy/microbiology ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*growth & development ; }, abstract = {Chronic osteomyelitis is difficult to treat, with biofilm growth and the diffusion barrier to antibiotics presented by bone contributory factors. The aim of this study was to develop and evaluate an in vitro model of osteomyelitis. A bioluminescent strain of Staphylococcus aureus was grown in bone blocks made from bovine femur. Light output was insufficient for detection of bacterial cells within bone by 24 h and viable counting of crushed bone blocks was used to determine bacterial survival. Challenge of 72 h biofilms with gentamicin and daptomycin for 24 h demonstrated that only concentrations of 10 times the clinical peak serum target levels (100 mg l[-1] gentamicin and 1000 mg l[-1] daptomycin) resulted in significant reductions in cell viability compared to controls. Once daily dosing over 7 days resulted in ≥3 log reductions in cell numbers by 48 h. Thereafter no significant reduction was achieved, although emergence of resistance was suppressed. Determination of antibiotic concentration in bone blocks over 7 days indicated that neither agent was able to consistently reach levels in bone of >10% of the original dose. The model was, therefore, able to demonstrate the challenges posed by biofilm growth on and within bone. SIGNIFICANCE AND IMPACT OF THE STUDY: The majority of studies of antibiotic efficacy in the treatment of chronic osteomyelitis are carried out in animals. We developed an in vitro model of Staphylococcus aureus infection of bone to evaluate the ability of antibiotics to eradicate mature biofilms on surfaces analogous to necrotic bone. The results demonstrated the difficulties which occur in osteomyelitis treatment, with only very high concentrations of antibiotic able to penetrate the bone sufficiently to reduce bacterial survival whilst still failing to eradicate biofilms. This model could be of use in initial screening of novel compounds intended for use in the treatment of osteomyelitis.}, } @article {pmid30770403, year = {2019}, author = {Liu, YL and He, TT and Liu, LY and Yi, J and Nie, P and Yu, HB and Xie, HX}, title = {The Edwardsiella piscicida Type III Translocon Protein EseC Inhibits Biofilm Formation by Sequestering EseE.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {8}, pages = {}, pmid = {30770403}, issn = {1098-5336}, mesh = {Animals ; Bacterial Proteins/*antagonists & inhibitors/genetics/metabolism ; Biofilms/*drug effects ; Calcium-Binding Proteins ; Edwardsiella/*drug effects/genetics ; Fish Diseases/microbiology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Membrane Glycoproteins ; Operon/genetics ; Receptors, Cytoplasmic and Nuclear ; Receptors, Peptide ; Type III Secretion Systems/*drug effects ; Virulence Factors/metabolism ; }, abstract = {The type III secretion system (T3SS) is one of the most important virulence factors of the fish pathogen Edwardsiella piscicida It contains three translocon proteins, EseB, EseC, and EseD, required for translocation of effector proteins into host cells. We have previously shown that EseB forms filamentous appendages on the surface of E. piscicida, and these filamentous structures mediate bacterial cell-cell interactions promoting autoaggregation and biofilm formation. In the present study, we show that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida At 18 h postsubculture, a ΔeseC strain developed strong autoaggregation and mature biofilm formation, accompanied by enhanced formation of EseB filamentous appendages. This is in contrast to the weak autoaggregation and immature biofilm formation seen in the E. piscicida wild-type strain. EseE, a protein that directly binds to EseC and also positively regulates the transcription of the escC-eseE operon, was liberated and showed increased levels in the absence of EseC. This led to augmented transcription of the escC-eseE operon, thereby increasing the steady-state protein levels of intracellular EseB, EseD, and EseE, as well as biofilm formation. Notably, the levels of intracellular EseB and EseD produced by the ΔeseE and ΔeseC ΔeseE strains were similar but remarkably lower than those produced by the wild-type strain at 18 h postsubculture. Taken together, we have shown that the translocon protein EseC inhibits biofilm formation through sequestering EseE, a positive regulator of the escC-eseE operon.IMPORTANCEEdwardsiella piscicida, previously known as Edwardsiella tarda, is a Gram-negative intracellular pathogen that mainly infects fish. The type III secretion system (T3SS) plays a pivotal role in its pathogenesis. The T3SS translocon protein EseB is required for the assembly of filamentous appendages on the surface of E. piscicida The interactions between the appendages facilitate autoaggregation and biofilm formation. In this study, we explored the role of the other two translocon proteins, EseC and EseD, in biofilm formation. We have demonstrated that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida, providing new insights into the regulatory mechanism involved in E. piscicida biofilm formation.}, } @article {pmid30770093, year = {2019}, author = {Dorji, D and Graham, RM and Singh, AK and Ramsay, JP and Price, P and Lee, S}, title = {Immunogenicity and protective potential of Bordetella pertussis biofilm and its associated antigens in a murine model.}, journal = {Cellular immunology}, volume = {337}, number = {}, pages = {42-47}, doi = {10.1016/j.cellimm.2019.01.006}, pmid = {30770093}, issn = {1090-2163}, mesh = {Adjuvants, Immunologic ; Animals ; Antibodies, Bacterial/blood ; Antigens/immunology ; Biofilms ; Bordetella pertussis/*immunology ; Disease Models, Animal ; Immunogenicity, Vaccine/*immunology ; Immunoglobulin G/blood/immunology ; Interferon-gamma/immunology ; Interleukin-17/immunology ; Male ; Mice ; Mice, Inbred BALB C ; Pertussis Vaccine/immunology ; Spleen/immunology ; Vaccination/methods ; Vaccines, Acellular/*immunology ; Whooping Cough/immunology ; }, abstract = {The resurgence of whooping cough reflects novel genetic variants of Bordetella pertussis and inadequate protection conferred by current acellular vaccines (aP). Biofilm is a source of novel vaccine candidates, including membrane protein assembly factor (BamB) and lipopolysaccharide assembly protein (LptD). Responses of BALB/c mice to candidate vaccines included IFN-γ and IL-17a production by spleen and lymph node cells, and serum IgG1 and IgG2a reactive with whole bacteria or aP. Protection was determined using bacterial cultured from lungs of vaccinated mice challenged with virulent B. pertussis. Mice vaccinated with biofilm produced efficient IFN-γ responses and more IL-17a and IgG2a than mice vaccinated with planktonic cells, aP or adjuvant alone. Vaccination with aP produced abundant IgG1 with little IgG2a. Mice vaccinated with aP plus BamB and LptD retained lower bacterial loads than mice vaccinated with aP alone. Whooping cough vaccines formulated with biofilm antigens, including BamB and LptD, may have clinical value.}, } @article {pmid30769135, year = {2019}, author = {Ashton, NN and Allyn, G and Porter, ST and Haussener, TJ and Sebahar, PR and Looper, RE and Williams, DL}, title = {In vitro testing of a first-in-class tri-alkylnorspermidine-biaryl antibiotic in an anti-biofilm silicone coating.}, journal = {Acta biomaterialia}, volume = {93}, number = {}, pages = {25-35}, doi = {10.1016/j.actbio.2019.02.010}, pmid = {30769135}, issn = {1878-7568}, support = {I01 RX001198/RX/RRD VA/United States ; }, mesh = {Alloys/chemistry ; Aluminum/chemistry ; Animals ; Anti-Bacterial Agents/*chemistry/therapeutic use ; Arthroplasty, Replacement ; Biofilms ; Coated Materials, Biocompatible/chemistry ; Delayed-Action Preparations/chemistry ; Diamines/*chemistry/therapeutic use ; Drug Delivery Systems ; Drug Liberation ; Gentamicins/*chemistry/pharmacology ; Humans ; Limit of Detection ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Sheep ; Silicones/*chemistry ; Spermidine/*analogs & derivatives/chemistry ; Staphylococcal Infections/*prevention & control ; Surface Properties ; Time Factors ; Titanium/chemistry ; Vanadium/chemistry ; Vancomycin/*chemistry/pharmacology ; }, abstract = {Biofilm-related infection is among the worst complication to prosthetic joint replacement procedures; once established on the implant surface, biofilms show strong recalcitrance to clinical antibiotic therapy, frequently requiring costly revision procedures and prolonged systemic antibiotics for their removal. A well-designed active release coating might assist host immunity in clearing bacterial contaminants within the narrow perioperative window and ultimately prevent microbial colonization of the joint prosthesis. A first-in-class compound (CZ-01127) was tested as the active release agent in a silicone (Si) coating using an in vitro dynamic flow model of surgical site contamination and compared with analogous coatings containing clinical gold-standard antibiotics vancomycin and gentamicin; the CZ-01127 coating outperformed both vancomycin and gentamicin coatings and was the only to decrease the methicillin-resistant Staphylococcus aureus (MRSA) inocula below detectable limits for the first 3 days. The antimicrobial activity of CZ-01127, and for comparison vancomycin and gentamicin, were characterized against both planktonic and biofilm MRSA using the minimum inhibitory concentration (MIC) assay, serial passages, and serial dilution tests against established biofilms grown with a CBR 90 CDC biofilm reactor. Despite a similar MIC (1 µg/ml) and behavior in a 25-day serial passage analysis, CZ-01127 displayed much greater bactericidal activity against established biofilms and was the only to decrease biofilm colony forming units (CFUs) below detectable limits at the highest concentration tested (500 µg/ml). Coating release profiles were characterized using ATR-FTIR and displayed burst release kinetics within the decisive period of the perioperative window suggesting the silicon carrier is broadly useful for screening antibiotic compound for local delivery applications. STATEMENT OF SIGNIFICANCE: With an aging population, an increasing number of people are undergoing total joint replacement procedures in which diseased joint tissues are replaced with permanent metallic implants. Some of these procedures are burdened by costly and debilitating infections. A promising approach to prevent infections is the use of an antimicrobial coating on the surface of the implant which releases antibiotics into the surgical site to prevent infection. In this study, we tested a new antibiotic compound formulated in a silicone coating. Data showed that this compound was more effective at killing pathogenic methicillin resistant Staphylococcus aureus (MRSA) bacteria than two clinical gold-standard antibiotics-vancomycin and gentamicin-and could be a promising agent for antimicrobial coating technologies.}, } @article {pmid30769118, year = {2019}, author = {Kovács, ÁT and Dragoš, A}, title = {Evolved Biofilm: Review on the Experimental Evolution Studies of Bacillus subtilis Pellicles.}, journal = {Journal of molecular biology}, volume = {431}, number = {23}, pages = {4749-4759}, doi = {10.1016/j.jmb.2019.02.005}, pmid = {30769118}, issn = {1089-8638}, mesh = {Bacillus subtilis/*physiology/virology ; Bacterial Physiological Phenomena ; Bacteriophages ; *Biofilms ; Biological Evolution ; Biological Variation, Population ; Gene Expression Regulation, Bacterial ; Gram-Positive Bacterial Infections/microbiology ; Host-Pathogen Interactions ; Microbial Interactions ; Phenotype ; }, abstract = {For several decades, laboratory evolution has served as a powerful method to manipulate microorganisms and to explore long-term dynamics in microbial populations. Next to canonical Escherichia coli planktonic cultures, experimental evolution has expanded into alternative cultivation methods and species, opening the doors to new research questions. Bacillus subtilis, the spore-forming and root-colonizing bacterium, can easily develop in the laboratory as a liquid-air interface colonizing pellicle biofilm. Here, we summarize recent findings derived from this tractable experimental model. Clonal pellicle biofilms of B. subtilis can rapidly undergo morphological and genetic diversification creating new ecological interactions, for example, exploitation by biofilm non-producers. Moreover, long-term exposure to such matrix non-producers can modulate cooperation in biofilms, leading to different phenotypic heterogeneity pattern of matrix production with larger subpopulation of "ON" cells. Alternatively, complementary variants of biofilm non-producers, each lacking a distinct matrix component, can engage in a genetic division of labor, resulting in superior biofilm productivity compared to the "generalist" wild type. Nevertheless, inter-genetic cooperation appears to be evanescent and rapidly vanquished by individual biofilm formation strategies altering the amount or the properties of the remaining matrix component. Finally, fast-evolving mobile genetic elements can unpredictably shift intra-species interactions in B. subtilis biofilms. Understanding evolution in clonal biofilm populations will facilitate future studies in complex multispecies biofilms that are more representative of nature.}, } @article {pmid30768237, year = {2019}, author = {Kang, M and Kim, S and Kim, H and Song, Y and Jung, D and Kang, S and Seo, JH and Nam, S and Lee, Y}, title = {Calcium-Binding Polymer-Coated Poly(lactide- co-glycolide) Microparticles for Sustained Release of Quorum Sensing Inhibitors to Prevent Biofilm Formation on Hydroxyapatite Surfaces.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {8}, pages = {7686-7694}, doi = {10.1021/acsami.8b18301}, pmid = {30768237}, issn = {1944-8252}, mesh = {Animals ; Biofilms/*drug effects ; Calcium/*chemistry/metabolism ; Cell Line ; Cell Survival/drug effects ; Drug Carriers/chemistry ; Durapatite/*chemistry ; Furans/chemistry/*pharmacology ; Methacrylates/chemistry ; Mice ; Polylactic Acid-Polyglycolic Acid Copolymer/*chemistry ; Polymers/chemical synthesis/*chemistry ; Quorum Sensing/*drug effects ; Streptococcus mutans/physiology ; Surface Properties ; }, abstract = {Quorum sensing (QS) inhibitor-based therapy is an attractive strategy to inhibit bacterial biofilm formation without excessive induction of antibiotic resistance. Thus, we designed Ca[2+]-binding poly(lactide- co-glycolide) (PLGA) microparticles that can maintain a sufficient concentration of QS inhibitors around hydroxyapatite (HA) surfaces in order to prevent biofilm formation on HA-based dental or bone tissues or implants and, therefore, subsequent pathogenesis. Poly(butyl methacrylate- co-methacryloyloxyethyl phosphate) (PBMP) contains both Ca[2+]-binding phosphomonoester groups and PLGA-interacting butyl groups. The PBMP-coated PLGA (PLGA/PBMP) microparticles exhibited superior adhesion to HA surfaces without altering the sustained release properties of uncoated PLGA microparticles. PLGA/PBMP microparticle-encapsulating furanone C-30, a representative QS inhibitor, effectively inhibited the growth of Streptococcus mutans and its ability to form biofilms on HA surface for prolonged periods of up to 100 h, which was much longer than either furanone C-30 in its free form or when encapsulated in noncoated PLGA microparticles.}, } @article {pmid30767811, year = {2019}, author = {Perez, LRR}, title = {Why do susceptible bacteria become resistant to infection control measures? A Pseudomonas biofilm example.}, journal = {Infection control and hospital epidemiology}, volume = {40}, number = {3}, pages = {386-388}, doi = {10.1017/ice.2018.348}, pmid = {30767811}, issn = {1559-6834}, mesh = {Biofilms ; Cross Infection ; Humans ; Infection Control ; Pseudomonas Infections/*transmission ; Pseudomonas aeruginosa/physiology ; }, } @article {pmid30767709, year = {2020}, author = {Liu, Y and Lin, C and Jia, H and Yong, X and Xie, X and Wu, X and Zhou, J and Wei, P}, title = {Effects of amino-modified biofilm carriers on biogas production in the anaerobic digestion of corn straw.}, journal = {Environmental technology}, volume = {41}, number = {21}, pages = {2806-2816}, doi = {10.1080/09593330.2019.1583290}, pmid = {30767709}, issn = {1479-487X}, mesh = {Anaerobiosis ; Biofilms ; *Biofuels ; Bioreactors ; Methane ; *Zea mays ; }, abstract = {This paper studied the property of three different biofilm carriers added into the anaerobic digestion systems, a granular activated carbon, a polyacrylonitrile, and a polyacrylonitrile modified with diethylenetriamine (PAN-NH2). The PAN-NH2 system kept the maximum biogas and methane production, which were 42.69% and 37.29% higher than the control system, respectively. The value of pH and chemical oxygen demand, the content of total solid and volatile solid, volatile fatty acids concentration, coenzyme F420 concentration, and microbial community analysis were investigated during the anaerobic digestion process. The PAN-NH2 system had the highest removal efficiency of the pollutants and regulated the pH of the system better than other systems. The result of high-throughput sequencing analysis showed that the addition of biofilm carriers and mediation with amino-groups adjusted system pH and improved biogas and CH4 production by reducing the relative abundance of bacteria in the hydrolysis/acidogenesis stages. Methanosarcina gradually replaced other methanogens during the experimental runs and was the dominant methanogen at the end of the anaerobic digestion process.}, } @article {pmid30767648, year = {2019}, author = {Mahmoudi, H and Pourhajibagher, M and Chiniforush, N and Soltanian, AR and Alikhani, MY and Bahador, A}, title = {Biofilm formation and antibiotic resistance in meticillin-resistant and meticillin-sensitive Staphylococcus aureus isolated from burns.}, journal = {Journal of wound care}, volume = {28}, number = {2}, pages = {66-73}, doi = {10.12968/jowc.2019.28.2.66}, pmid = {30767648}, issn = {0969-0700}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms ; *Burns ; Cross-Sectional Studies ; *Drug Resistance, Bacterial ; Humans ; Iran/epidemiology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Prevalence ; Staphylococcal Infections/*drug therapy/epidemiology/microbiology ; Staphylococcus aureus/*drug effects/isolation & purification ; }, abstract = {OBJECTIVE: To investigate the relationship between biofilm formation and antibiotic resistance patterns in meticillin-resistant and meticillin-sensitive Staphylococcus aureus, isolated from burns.

METHODS: In a cross-sectional study, pus/wound swab samples were obtained from burns. Presence of Staphylococcus aureus was confirmed, and biofilm formation-related icaABCDR and eta, etb genes were detected by polymerase chain reaction. Biofilm formation assay was assessed using the microtiter plate method. Antibiotic resistance was performed using the disk diffusion method and minimum inhibitory concentration.

RESULTS: A total of 95 patients with burns were recruited. Of the 95 wounds swabbed, Staphylococcus aureus was identified in 50 (62.5%), and 47 (94%) isolates capable of producing biofilm. Biofilm production levels were classed as 'strong' (n=29; 58%), 'moderate' (n=11; 22%), 'weak' (n=7; 14%) and 'non-biofilm forming' (n=3; 6%). There was an almost even split between isolates identified as meticillin-resistant Staphylococcus aureus (MRSA), n=24 (48%), and meticillin-sensitive Staphylococcus aureus (MSSA) n=26 (52%). The prevalence of the icaA, icaB, icaC, icaD and icaR genes among the studied isolates were 96%, 80%, 80%, 96% and 84%, respectively. The prevalence of eta and etb genes in isolates were 84% and 92%, respectively.

CONCLUSION: Biofilm producing isolates of Staphylococcus aureus showed greater multidrug resistance than non-biofilm producers. In our study, a high rate of biofilm formation and antimicrobial drug resistance was seen. Our results highlight the alarming levels of antimicrobial resistance among MRSA strains and important data about the prevalence of eta and etb genes in Staphylococcus aureus strains isolated from burn patients in this study.}, } @article {pmid30767627, year = {2020}, author = {Gupta, A and Cheepurupalli, L and Vigneswaran, S and Singh Rathore, S and Suma Mohan, S and Ramakrishnan, J}, title = {In vitro and in silico investigation of caprylic acid effect on multi drug resistant (MDR) Klebsiella pneumoniae biofilm.}, journal = {Journal of biomolecular structure & dynamics}, volume = {38}, number = {2}, pages = {616-624}, doi = {10.1080/07391102.2019.1581087}, pmid = {30767627}, issn = {1538-0254}, mesh = {Bacterial Proteins/chemistry ; Biofilms/*drug effects ; Biological Availability ; Caprylates/*pharmacology ; Catheters/microbiology ; *Computer Simulation ; *Drug Resistance, Multiple, Bacterial/drug effects ; Klebsiella pneumoniae/drug effects/*physiology ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Sodium Chloride/pharmacology ; Thermodynamics ; }, abstract = {Communicated by Ramaswamy H. Sarma.}, } @article {pmid30766602, year = {2019}, author = {Galdiero, E and Siciliano, A and Gesuele, R and Di Onofrio, V and Falanga, A and Maione, A and Liguori, R and Libralato, G and Guida, M}, title = {Melittin Inhibition and Eradication Activity for Resistant Polymicrobial Biofilm Isolated from a Dairy Industry after Disinfection.}, journal = {International journal of microbiology}, volume = {2019}, number = {}, pages = {4012394}, pmid = {30766602}, issn = {1687-918X}, abstract = {The emerging concern about the increase of antibiotic resistance and associated biofilm has encouraged scientists to look for alternative antibiotics such as antimicrobial peptides (AMPs). This study evaluated the ability of melittin to act as an antibacterial biofilm inhibitor and biofilm remover considering isolates from dairy industry. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities were studied in polymicrobial biofilms produced from isolates. MIC and MBC were set at 1-3 µg/mL and 25-50 µg/mL for Gram-positive and Gram-negative bacteria, respectively. Results demonstrated a good MBIC reaching 85% inhibition ability and a good activity and better penetration in deeper layers against the mixed preformed biofilm, thereby increasing its activity against all isolates also at the lowest tested concentrations. Melittin showed interesting characteristics suggesting its potential to act as an antimicrobial agent for polymicrobial biofilm from dairy industry even in environmental isolates.}, } @article {pmid30766582, year = {2018}, author = {Kadry, AA and El-Ganiny, AM and El-Baz, AM}, title = {Relationship between Sap prevalence and biofilm formation among resistant clinical isolates of Candida albicans.}, journal = {African health sciences}, volume = {18}, number = {4}, pages = {1166-1174}, pmid = {30766582}, issn = {1729-0503}, mesh = {Antifungal Agents/pharmacology ; Aspartic Acid Endopeptidases/*genetics ; Biofilms ; Candida albicans/classification/*genetics/*isolation & purification/physiology ; Drug Resistance, Fungal/*genetics ; Fungal Proteins/*genetics ; Genotype ; Humans ; Microbial Sensitivity Tests ; Peptide Hydrolases/metabolism ; Phenotype ; Prevalence ; Virulence ; Virulence Factors ; }, abstract = {BACKGROUND: Fungal infections represent a serious health problem especially in immunocompromised individuals. Candida albicans is the most common fungi that cause superficial and systemic infections with high mortality rates. Anti-fungal resistance of C. albicans may be attributed to its virulence. Biofilm formation and proteolytic activity are major virulence determents that may influence both pathogenicity and anti-fungal resistance of Candida albicans.

OBJECTIVE: This work studied the relation between biofilm formation, proteolytic activity and prevalence of some Sap genes with reduced susceptibility of C. albicans to different anti-fungal agents.

METHODS: Fifty three C. albicans strains isolated from patients with systemic infections, identified by germ tube, chromogenic agar and confirmed by PCR, were subjected to evaluate their proteolytic activity, the degree of biofilm production and the prevalence of Sap9 and Sap10 genes. The susceptibility of the isolates was determined by disk diffusion method against five antifungal drugs.

RESULTS AND CONCLUSION: Four of the C. albicans isolates were resistant to 3 anti-fungal drugs, strong biofilm producer, have proteolytic activity and contain either Sap9 or Sap10 or both. Conclusively, although anti-fungal resistance among the isolates was rare, a relation between the anti-fungal resistance and some major virulence factors was evidently proved in this study.}, } @article {pmid30763694, year = {2019}, author = {Doğan, Ş and Gökalsın, B and Şenkardeş, İ and Doğan, A and Sesal, NC}, title = {Anti-quorum sensing and anti-biofilm activities of Hypericum perforatum extracts against Pseudomonas aeruginosa.}, journal = {Journal of ethnopharmacology}, volume = {235}, number = {}, pages = {293-300}, doi = {10.1016/j.jep.2019.02.020}, pmid = {30763694}, issn = {1872-7573}, mesh = {Anti-Bacterial Agents/administration & dosage/isolation & purification/*pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; Hypericum/*chemistry ; Medicine, Traditional/methods ; Microbial Sensitivity Tests ; Plant Components, Aerial ; Plant Extracts/administration & dosage/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/drug effects ; }, abstract = {Hypericum perforatum L. (Hypericaceae) has been used as a traditional therapeutic for skin wounds, burns, cuts and stomach ailments including stomach ache, ulcers for a long time in many societies. Although many studies about its antibacterial properties can be found, there is a lack of studies about its quorum sensing inhibition properties, which effects bacterial vulnerability directly, on Pseudomonas aeruginosa.

AIM OF THE STUDY: Evaluation of anti-quorum sensing (anti-QS) and anti-biofilm activity of ethanol, methanol, acetone and ultra-sonicated extracts of Hypericum perforatum L. (HP) which is a well-known wound healer, against P. aeruginosa.

MATERIALS AND METHODS: Aerial parts of HP were extracted with ethanol, methanol and acetone. In addition, separate extractions with ultrasonication were carried out with same solvents. Anti-QS activity tests with different doses of HP extracts were performed by employing biomonitor strains, of which the promoter of QS regulating and green fluorescent protein (GFP) genes were fusioned. For anti-biofilm activity, HP extracts were applied to wild type PAO1 strains and biofilm inhibition was quantified via crystal violet staining method.

RESULTS: HP's ethanol, methanol and acetone extracts (250 µg/ml doses) inhibited LasIR signalling pathway up to 65.43%, 59.60%, 55.95% and same solvent extracts obtained with ultrasonication inhibited 71.33%, 64.47%, 57.35% respectively. Moreover, inhibition rates of RhlIR pathway were 28.80%, 50.83%, 45.84% for ethanol, methanol, acetone extracts (250 µg/ml doses) and 51.43%, 57.41%, 50.02% for ultrasonication extracts (250 µg/ml doses), compared to untreated controls. In the experiments, ethanol, methanol, acetone and ultra-sonicated extracts of HP did not inhibit biofilm formation.

CONCLUSIONS: This study shows that HP plant is capable for blocking of las and rhl QS systems of P. aeruginosa. However, it was observed that ethanol, methanol and acetone extract of the plant samples did not show anti-biofilm activity against P. aeruginosa. This led us to thinking that biofilm formation was caused via another pathway such as IQS or PQS. Further studies with isolated active compounds of HP might give a better understanding of the effects on biofilm formation of P. aeruginosa.}, } @article {pmid30763382, year = {2019}, author = {Cooke, AC and Nello, AV and Ernst, RK and Schertzer, JW}, title = {Analysis of Pseudomonas aeruginosa biofilm membrane vesicles supports multiple mechanisms of biogenesis.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0212275}, pmid = {30763382}, issn = {1932-6203}, mesh = {Bacterial Outer Membrane Proteins/metabolism ; *Biofilms ; Humans ; Membrane Lipids/metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/cytology/*physiology ; Quinolones/metabolism ; Quorum Sensing ; }, abstract = {Outer Membrane Vesicles (OMVs) are ubiquitous in bacterial environments and enable interactions within and between species. OMVs are observed in lab-grown and environmental biofilms, but our understanding of their function comes primarily from planktonic studies. Planktonic OMVs assist in toxin delivery, cell-cell communication, horizontal gene transfer, small RNA trafficking, and immune system evasion. Previous studies reported differences in size and proteomic cargo between planktonic and agar plate biofilm OMVs, suggesting possible differences in function between OMV types. In Pseudomonas aeruginosa interstitial biofilms, extracellular vesicles were reported to arise through cell lysis, in contrast to planktonic OMV biogenesis that involves the Pseudomonas Quinolone Signal (PQS) without appreciable autolysis. Differences in biogenesis mechanism could provide a rationale for observed differences in OMV characteristics between systems. Using nanoparticle tracking, we found that P. aeruginosa PAO1 planktonic and biofilm OMVs had similar characteristics. However, P. aeruginosa PA14 OMVs were smaller, with planktonic OMVs also being smaller than their biofilm counterparts. Large differences in Staphylococcus killing ability were measured between OMVs from different strains, and a smaller within-strain difference was recorded between PA14 planktonic and biofilm OMVs. Across all conditions, the predatory ability of OMVs negatively correlated with their size. To address biogenesis mechanism, we analyzed vesicles from wild type and pqsA mutant biofilms. This showed that PQS is required for physiological-scale production of biofilm OMVs, and time-course analysis confirmed that PQS production precedes OMV production as it does in planktonic cultures. However, a small sub-population of vesicles was detected in pqsA mutant biofilms whose size distribution more resembled sonicated cell debris than wild type OMVs. These results support the idea that, while a small and unique population of vesicles in P. aeruginosa biofilms may result from cell lysis, the PQS-induced mechanism is required to generate the majority of OMVs produced by wild type communities.}, } @article {pmid30763337, year = {2019}, author = {Jijón-Moreno, S and Baca, BE and Castro-Fernández, DC and Ramírez-Mata, A}, title = {TyrR is involved in the transcriptional regulation of biofilm formation and D-alanine catabolism in Azospirillum brasilense Sp7.}, journal = {PloS one}, volume = {14}, number = {2}, pages = {e0211904}, pmid = {30763337}, issn = {1932-6203}, mesh = {*Aspergillus/chemistry/physiology ; Biofilms/*growth & development ; D-Amino-Acid Oxidase/biosynthesis/genetics ; *Fungal Proteins/chemistry/genetics ; Helix-Turn-Helix Motifs ; Protein Domains ; Response Elements ; *Transcription Factors/chemistry/genetics/metabolism ; Transcription, Genetic/physiology ; }, abstract = {Azospirillum brasilense is one of the most studied species of diverse agronomic plants worldwide. The benefits conferred to plants inoculated with Azospirillum have been primarily attributed to its capacity to fix atmospheric nitrogen and synthesize phytohormones, especially indole-3-acetic acid (IAA). The principal pathway for IAA synthesis involves the intermediate metabolite indole pyruvic acid. Successful colonization of plants by Azospirillum species is fundamental to the ability of these bacteria to promote the beneficial effects observed in plants. Biofilm formation is an essential step in this process and involves interactions with the host plant. In this study, the tyrR gene was cloned, and the translated product was observed to exhibit homology to TyrR protein, a NtrC/NifA-type activator. Structural studies of TyrR identified three putative domains, including a domain containing binding sites for aromatic amino acids in the N-terminus, a central AAA+ ATPase domain, and a helix-turn-helix DNA binding motif domain in the C-terminus, which binds DNA sequences in promoter-operator regions. In addition, a bioinformatic analysis of promoter sequences in A. brasilense Sp7 genome revealed that putative promoters encompass one to three TyrR boxes in genes predicted to be regulated by TyrR. To gain insight into the phenotypes regulated by TyrR, a tyrR-deficient strain derived from A. brasilense Sp7, named A. brasilense 2116 and a complemented 2116 strain harboring a plasmid carrying the tyrR gene were constructed. The observed phenotypes indicated that the putative transcriptional regulator TyrR is involved in biofilm production and is responsible for regulating the utilization of D-alanine as carbon source. In addition, TyrR was observed to be absolutely required for transcriptional regulation of the gene dadA encoding a D-amino acid dehydrogenase. The data suggested that TyrR may play a major role in the regulation of genes encoding a glucosyl transferase, essential signaling proteins, and amino acids transporters.}, } @article {pmid30762887, year = {2019}, author = {Vipin, C and Mujeeburahiman, M and Ashwini, P and Arun, AB and Rekha, PD}, title = {Anti-biofilm and cytoprotective activities of quercetin against Pseudomonas aeruginosa isolates.}, journal = {Letters in applied microbiology}, volume = {68}, number = {5}, pages = {464-471}, doi = {10.1111/lam.13129}, pmid = {30762887}, issn = {1472-765X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Cell Line ; Drug Resistance, Multiple, Bacterial ; HEK293 Cells ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects/*growth & development/isolation & purification ; Quercetin/*pharmacology ; Virulence ; Virulence Factors ; }, abstract = {Increase in infection with multidrug resistant Pseudomonas aeruginosa is a serious global challenge in healthcare. Pseudomonas aeruginosa is capable of causing human infection in various sites and complicates the infection due to its virulence factors. This study was aimed to investigate the effect of quercetin, a dietary flavonoid against the virulence factors of P. aeruginosa and its cell protective effects on epithelial cells. Bactericidal activity, anti-biofilm activity and effect on different virulence factors were carried out using standard methods by using five P. aeruginosa isolates. Cytotoxicity and cell protective effect of quercetin was evaluated by trypan blue dye exclusion assay. All the tested isolates were completely inhibited (100%) by quercetin at a concentration of 500 μg ml[-1] . It showed significant (P < 0·05) inhibitory effect on virulence factors including biofilm formation and showed significant protective effect on HEK 293T cells infected with P. aeruginosa strains. This study supports the role of quercetin against P. aeruginosa, by inhibiting virulence factors as well as its cytoprotective activity during bacterial infection either by attenuating the virulence or providing direct protective effect to the host cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The increase in infections caused by opportunistic pathogen Pseudomonas aeruginosa is a serious concern in the health care system. This study describes the beneficial effects of a dietary flavonoid, quercetin against pathogenic P. aeruginosa strains and its protective effect against the P. aeruginosa infection in HEK 293T cells in vitro.}, } @article {pmid30760047, year = {2020}, author = {Dodou, HV and Batista, AHM and Medeiros, SC and Sales, GWP and Rodrigues, ML and Pereira, PIO and Nogueira, PCN and Silveira, ER and Grangeiro, TB and Nogueira, NAP}, title = {Violacein antimicrobial activity on Staphylococcus epidermidis biofilm.}, journal = {Natural product research}, volume = {34}, number = {23}, pages = {3414-3417}, doi = {10.1080/14786419.2019.1569654}, pmid = {30760047}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; Drug Synergism ; Indoles/administration & dosage/pharmacology ; Microbial Sensitivity Tests ; Staphylococcus epidermidis/*drug effects ; Vancomycin/pharmacology ; }, abstract = {The aim of this study was to evaluate the antimicrobial potential of violacein (VIO) on Staphylococcus epidermidis biofilm. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were determined, as well as the effect of VIO exposure time on microbial viability in mature biofilm. Violacein showed good antibiofilm action, inhibiting biofilm formation and eradicating mature biofilm of S. epidermidis at concentrations of 20 μg.mL[-1] and 160 μg.mL[-1], respectively. At concentrations equal to MBEC and 2x MBEC, the biofilm was eradicated in 3 h and 2h30min of incubation, respectively.When evaluating VIO modulating effect on the action of clinically-used drugs (vancomycin, cefepime, ciprofloxacin and meropenem), especial synergism was observed in the violacein-ciprofloxacin association, it can completely erradicated the mature biofilm at the concentration of 1/2xMBEC and 1/4xMBEC, respectively. VIO shows good antimicrobial action on S. epidermidis biofilm and has the potential to synergistically modulate the activity of clinically-used antimicrobials.}, } @article {pmid30758060, year = {2019}, author = {Costa, DM and Johani, K and Melo, DS and Lopes, LKO and Lopes Lima, LKO and Tipple, AFV and Hu, H and Vickery, K}, title = {Biofilm contamination of high-touched surfaces in intensive care units: epidemiology and potential impacts.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {269-276}, doi = {10.1111/lam.13127}, pmid = {30758060}, issn = {1472-765X}, support = {2015142//Macquarie University/ ; 8210300211//Australian Research Council/ ; 99999.006361/2014-05//Coordination for the Improvement of Higher Education Personnel (CAPES) Scholarship/ ; 99999.006360/2014-09//Coordination for the Improvement of Higher Education Personnel (CAPES) Scholarship/ ; //Medical Services Department (MSD) of the Ministry of Defense and Aviation, Saudi Arabia/ ; }, mesh = {Acinetobacter baumannii/growth & development/isolation & purification ; Biofilms/*growth & development ; Brazil ; Cross Infection/prevention & control ; Disinfection/*methods ; Drug Resistance, Multiple, Bacterial ; Enterococcus faecium/growth & development/isolation & purification ; Equipment Contamination/prevention & control/*statistics & numerical data ; Humans ; Infant, Newborn ; *Intensive Care Units ; Klebsiella pneumoniae/growth & development/isolation & purification ; Microbiota ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Pseudomonas aeruginosa/growth & development/isolation & purification ; RNA, Ribosomal, 16S ; Staphylococcus aureus/growth & development/isolation & purification ; }, abstract = {The aim of this study was to determine the epidemiology (location, microbial load, microbiome, presence/absence of biofilm and pathogens, including ESKAPE-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species, and antimicrobial susceptibility profiles) of the bacterial contamination on intensive care units (ICUs) surfaces. Fifty-seven high-touched surfaces were collected from adult, paediatric and neonatal ICUs from two large public Brazilian hospitals from central and north regions. Samples (c. 4 cm[2]) were subjected to culture (qualitative), qPCR targeting 16s rRNA gene (microbial load-bacteria per cm[2]), 16s rRNA amplicon sequencing (microbiome analysis) and scanning electron (SEM) or confocal laser scanning microscopy (CLSM) (biofilm presence). Multidrug resistant organisms (MROs) were detected using specific chromogenic agar. The average bacterial load was 1·32 × 10[4] bacteria per cm[2] , container for newborn feeding bottles, stretcher mattress, humidicrib mattress filling and computer keyboards presented the higher bioburden. However, only 45·6% (26/57) were culture-positive, including 4/26 with MROs. ESKAPE organisms were detected in 51·8% of the samples subjected to next-generation sequencing. Viability staining and CLSM demonstrated live bacteria on 76·7% of culture-negative samples. Biofilm was present on all surfaces subjected to microscopy (n = 56), demonstrating that current cleaning practices are suboptimal and reinforcing that MROs are incorporated into hospital surfaces biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination of healthcare facilities surfaces has been shown to play a major role in transmission of pathogens. The findings of this study show that dry surface biofilms are widespread and can incorporate pathogens and multidrug-resistant organisms (MROs). Biofilms on highly touched surfaces pose a risk to patients, as dry surface biofilms persist for long period and micro-organisms within biofilm have been shown to be transmitted. This study also provides a better understanding of microbial populations in hospital environments, reinforcing that pathogens and MROs are found incorporated into biofilm, which impacts the difficulty in cleaning/disinfection.}, } @article {pmid30747987, year = {2018}, author = {Holý, O and Matoušková, I and Zatloukalová, S and Dvořáčková, M and Petrželová, J and Raida, L and Růžička, F}, title = {[Prevalence of strains of Staphylococcus epidermidis and other coagulase-negative staphylococci with biofilm-forming ability at a department of hemato-oncology].}, journal = {Klinicka mikrobiologie a infekcni lekarstvi}, volume = {24}, number = {3}, pages = {68-72}, pmid = {30747987}, issn = {1211-264X}, mesh = {*Biofilms ; Coagulase/metabolism ; Humans ; Prevalence ; *Staphylococcal Infections/epidemiology/microbiology ; *Staphylococcus epidermidis/physiology ; }, abstract = {OBJECTIVES: Staphylococcus epidermidis and coagulase-negative staphylococci generally are important causative agents of hospital-acquired infections. A significant role in this process is played by their common ability to form biofilm, a highly organized community of microorganisms adhering to inert surfaces. The study aimed to determine the prevalence of these bacterial strains and their ability to form biofilm at the Department of Hemato-Oncology, University Hospital Olomouc.

MATERIAL AND METHODS: Over a period of 12 months, samples of air and swabs from surfaces and staff members were collected. The samples were subjected to standard microbiology tests; coagulase-negative staphylococci were identified. Staphylococcus epidermidis strains were confirmed by polymerase chain reaction and subsequently tested for biofilm formation.

RESULTS AND CONCLUSIONS: Coagulase-negative staphylococci were found in 81 samples, most commonly swabs from staff members. S. epidermidis accounted for 60 % of all positive results; it was most frequently isolated from surface swabs. Almost half of S. epidermidis strains were able to form biofilm. These strains were found in the environment characterized by cleanliness classes FED-STD-209E (USA) - 10 000 and FED-STD-209E (USA) - 100 000. Thus, they pose a risk for immunocompromised patients staying there. Since coagulase-negative staphylococci were also found in healthcare staff of the department, the staff members may play a key role in the transmission of these microorganisms to patients.}, } @article {pmid30745897, year = {2019}, author = {Martins, KB and Ferreira, AM and Pereira, VC and Pinheiro, L and de Oliveira, A and da Cunha, MLRS}, title = {In vitro Effects of Antimicrobial Agents on Planktonic and Biofilm Forms of Staphylococcus saprophyticus Isolated From Patients With Urinary Tract Infections.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {40}, pmid = {30745897}, issn = {1664-302X}, abstract = {Bacterial biofilms play an important role in urinary tract infections (UTIs), being responsible for persistent infections that lead to recurrences and relapses. Staphylococcus saprophyticus is one of the main etiological agents of UTIs, however, little is known about biofilm production in this species and especially about its response to the antimicrobial agents used to treat UTIs when a biofilm is present. For this reason, the aim of this work was to evaluate the response of S. saprophyticus biofilms to five antimicrobial agents. Staphylococcus saprophyticus was evaluated for antimicrobial susceptibility in its planktonic form by means of minimum inhibitory concentration (MIC) and in biofilms by means of minimum inhibitory concentration in biofilm (MICB) against the following antimicrobial agents by the microdilution technique: vancomycin, oxacillin, trimethoprim/sulfamethoxazole, ciprofloxacin, and norfloxacin. Of the 169 S. saprophyticus studied, 119 produced a biofilm as demonstrated by the polystyrene plate adherence method. Biofilm cells of S. saprophyticus exhibited a considerable increase in MICB when compared to the planktonic forms, with an increase of more than 32 times in the MICB of some drugs. Some isolates switched from the category of susceptible in the planktonic condition to resistant in the biofilm state. Statistical analysis of the results showed a significant increase in MICB (p < 0.0001) for all five drugs tested in the biofilm state compared to the planktonic form. Regarding determination of the minimum bactericidal concentration in biofilm (MBCB), there were isolates for which the minimum bactericidal concentration of all drugs was equal to or higher than the highest concentration tested.}, } @article {pmid30744421, year = {2018}, author = {Souza, JGS and Lima, CV and Costa Oliveira, BE and Ricomini-Filho, AP and Faveri, M and Sukotjo, C and Feres, M and Del Bel Cury, AA and Barão, VAR}, title = {Dose-response effect of chlorhexidine on a multispecies oral biofilm formed on pure titanium and on a titanium-zirconium alloy.}, journal = {Biofouling}, volume = {34}, number = {10}, pages = {1175-1184}, doi = {10.1080/08927014.2018.1557151}, pmid = {30744421}, issn = {1029-2454}, mesh = {*Alloys ; Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; Dose-Response Relationship, Drug ; Prostheses and Implants/*microbiology ; *Titanium ; *Zirconium ; }, abstract = {This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.}, } @article {pmid30744166, year = {2019}, author = {Kang, Y and Li, L and Li, S and Zhou, X and Xia, K and Liu, C and Qu, Q}, title = {Temporary Inhibition of the Corrosion of AZ31B Magnesium Alloy by Formation of Bacillus subtilis Biofilm in Artificial Seawater.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {3}, pages = {}, pmid = {30744166}, issn = {1996-1944}, support = {51661033, 51361028, 51161025, and 31660538.//National Natural Science Foundation of China/ ; }, abstract = {It is well known that microorganisms tend to form biofilms on metal surfaces to accelerate/decelerate corrosion and affect their service life. Bacillus subtilis was used to produce a dense biofilm on an AZ31B magnesium alloy surface. Corrosion behavior of the alloy with the B. subtilis biofilm was evaluated in artificial seawater. The results revealed that the biofilm hampered extracellular electron transfer significantly, which resulted in a decrease of icorr and increase of Rt clearly compared to the control group. Moreover, an ennoblement of Ecorr was detected under the condition of B. subtilis biofilm covering. Significant reduction of the corrosion was observed by using the cyclic polarization method. All of these prove that the existence of the B. subtilis biofilm effectively enhances the anti-corrosion performance of the AZ31B magnesium alloy. This result may enhance the usage of bio-interfaces for temporary corrosion control. In addition, a possible corrosion inhibition mechanism of B. subtilis on AZ31B magnesium alloy was proposed.}, } @article {pmid30743828, year = {2018}, author = {Lai, CY and Dong, QY and Zhao, HP}, title = {Oxygen exposure deprives antimonate-reducing capability of a methane fed biofilm.}, journal = {The Science of the total environment}, volume = {644}, number = {}, pages = {1152-1159}, doi = {10.1016/j.scitotenv.2018.07.047}, pmid = {30743828}, issn = {1879-1026}, mesh = {Antimony/*metabolism ; Biofilms ; Bioreactors/*microbiology ; Methane/*metabolism ; Oxygen/metabolism ; Waste Disposal, Fluid/methods ; }, abstract = {This work is aiming at achieving antimonate (Sb(V)) bio-reduction in a methane (CH4) based membrane biofilm reactor (MBfR), and elucidating the effect of oxygen (O2) on the performance of the biofilm. Scanning electron microscope (SEM), energy dispersive X-ray (EDS) and X-ray photoelectron spectroscopy (XPS) confirm Sb2O3 precipitates were the main product formed from Sb(V) reduction in the CH4-fed biofilm. Illumina sequencing shows Thermomonas may be responsible for Sb(V) reduction. Moreover, we found 8 mg/L of O2 in the influent irreversibly inhibited Sb(V) reduction. Metagenomic prediction by Reconstruction of Unobserved State (PICRUSt) shows that the biofilm lacked efficient defense system to the oxidative stress, leading to the great suppress of key biological metabolisms such as TCA cycle, glycolysis and DNA replication, as well as potential Sb(V) reductases, by O2. However, methanotrophs Methylomonas and Methylosinus were enriched in the biofilm with O2 intrusion, in accordance with the enhanced abundance of genes encoding aerobic CH4 oxidation. These insights evoke the theoretical guidance of microbial remediation using CH4 as the electron donor towards Sb(V) contamination, and will give us a strong reference with regard to wastewater disposal.}, } @article {pmid30743237, year = {2019}, author = {Chen, X and Xiong, X and Jiang, X and Shi, H and Wu, C}, title = {Sinking of floating plastic debris caused by biofilm development in a freshwater lake.}, journal = {Chemosphere}, volume = {222}, number = {}, pages = {856-864}, doi = {10.1016/j.chemosphere.2019.02.015}, pmid = {30743237}, issn = {1879-1298}, mesh = {Biofilms/*growth & development ; *Environmental Monitoring ; Environmental Pollution/analysis ; Lakes/*microbiology ; Plastics/*analysis ; Polypropylenes ; *Seasons ; Waste Products/analysis ; }, abstract = {Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics lost buoyancy in summer while only a small portion lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment.}, } @article {pmid30743061, year = {2019}, author = {Zhang, R and Neu, TR and Blanchard, V and Vera, M and Sand, W}, title = {Biofilm dynamics and EPS production of a thermoacidophilic bioleaching archaeon.}, journal = {New biotechnology}, volume = {51}, number = {}, pages = {21-30}, doi = {10.1016/j.nbt.2019.02.002}, pmid = {30743061}, issn = {1876-4347}, mesh = {Archaea/*metabolism ; *Biofilms ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; *Temperature ; }, abstract = {Bioleaching of metal sulfides represents an interfacial process where biofilm formation is important in the initial steps of this process. In technical applications of bioleaching, such as reactor leaching in the temperature range of 50 up to 90 °C and also in (self-heating) heaps, thermophilic archaea play an important role and often are the leaching organisms of choice. Nevertheless, to date there is little information available on the interactions between thermoacidophilic archaea and their natural mineral substrates such as pyrite. Especially for extracellular polymeric substances (EPS) of archaea and their biofilms in bioleaching environments information is rather limited. The present work focused on investigations of biofilm dynamics and EPS production of the thermoacidophilic archaeon Acidianus sp. DSM 29099 under bioleaching conditions. The results show that biofilms are dispersed non-homogeneously on pyrite. Large parts of the pyrite surfaces remain free of cells. Cell detachment from pyrite results in microbial "footprints" which, based on lectin binding assays, consist of mannose, glucose and fucose containing compounds. A monolayer biofilm develops on pyrite after 2-4 days of incubation. In addition, the pyrite surface is covered with a layer of organic compounds. EPS analysis indicates the presence of proteins, polysaccharides and uronic acids, the composition of which varies according to substrate and lifestyle (i.e. planktonic, biofilm cells). This report provides insight into EPS and biofilm characteristics of thermophilic archaea and improves understanding of the mineral-microbial-biofilm interfacial interactions in extreme environments. Moreover, the results on interaction dynamics of archaeal microbial consortia will facilitate the understanding of thermophilic bioleaching.}, } @article {pmid30742947, year = {2019}, author = {Tozar, T and Nastasa, V and Stoicu, A and Chifiriuc, MC and Popa, M and Kamerzan, C and Pascu, ML}, title = {In vitro antimicrobial efficacy of laser exposed chlorpromazine against Gram-positive bacteria in planktonic and biofilm growth state.}, journal = {Microbial pathogenesis}, volume = {129}, number = {}, pages = {250-256}, doi = {10.1016/j.micpath.2019.02.012}, pmid = {30742947}, issn = {1096-1208}, mesh = {Biofilms/*drug effects ; Chlorpromazine/*pharmacology ; Flow Cytometry ; Gram-Positive Bacteria/*drug effects ; Low-Level Light Therapy/*methods ; Microbial Sensitivity Tests ; }, abstract = {Aqueous chlorpromazine solutions exposed to 266 nm generated as fourth harmonic of Nd:YAG pulsed laser along time intervals from 1 min to 240 min were investigated for their antimicrobial activity against planktonic and adherent Gram-positive bacterial strains. Qualitative and quantitative assays based on microbiological methods and flow cytometry assays were performed to establish the minimum inhibitory and minimum biofilm eradication concentrations and to reveal some of the possible mechanisms of antimicrobial activity. Optimal irradiation conditions and combinations of photoproducts for achieving the best antimicrobial and antibiofilm effects are suggested. It was confirmed that chlorpromazine solutions irradiated for 15 min and 30 min have the best antimicrobial and antibiofilm activity against Staphylococcus aureus ATCC 6538, methicillin susceptible Staphylococcus aureus, methicillin resistant Staphylococcus aureus, Enterococcus faecium 17-VAR, Enterococcus faecalis 2921, and Bacillus subtilis 6633. Flow cytometry revealed that two of the possible mechanisms of the antimicrobial activity of irradiated chlorpromazine are the inhibition of efflux pumps activity and induction of cellular membrane lesions.}, } @article {pmid30742347, year = {2019}, author = {Chen, S and Chen, Y and Pei, H and Hou, Q}, title = {Biofilm development dynamics and pollutant removal performance of ceramsite made from drinking-water treatment sludge.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {91}, number = {7}, pages = {616-627}, doi = {10.1002/wer.1089}, pmid = {30742347}, issn = {1554-7531}, support = {51322811//National Science Fund for Excellent Young Scholars/ ; NCET-12-0341//University of the Ministry of Education of China/ ; ZR2016EEB26//Foundation for Outstanding Young Scientists in Shandong Province/ ; 51378300//Natural Science Foundation of China/ ; }, mesh = {*Biofilms ; Complex Mixtures/*chemistry ; *Denitrification ; Microbiota ; Nitrogen/*isolation & purification ; Phosphorus/*isolation & purification ; Sewage ; Water Purification/*methods ; Wetlands ; }, abstract = {Alum-sludge ceramsite and denitrifying bacteria (XP-1, XP-2, CL-1, CL-3) were used as substrate and constructed biofilm for enhancing the removal of pollutants from wastewater. The results showed that, due to the large specific surface area, the maximum growth rate was 0.49 mg/(g·day) on the sludge ceramsite, and the mass of biofilm attached onto sludge ceramsite was 5.98 times higher than that when using commercial ceramsite as substrate. Better removal performance could be achieved with the combination of sludge ceramsite and bacteria, viz. 98.6%, 91.0%, and 85.8% reduction in total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD), respectively. Pseudo-first-order kinetics, pseudo-second-order kinetics, Monod kinetics, and multiple Monod kinetics combined with continuous-flow-stirred tank reactor (CFSTR) behavior were used to investigate the dynamics of the pollutant removal processes. The decrease in band brightness for bacteria attached onto sludge ceramsite was 11.5%, while it was more than 35.7% on commercial ceramsite during wastewater treatment according to results from denaturing gradient gel electrophoresis (DGGE). Sludge ceramsite played an important role in maintaining quantities and activities of denitrifying bacteria, and application of sludge ceramsite substrate and denitrifying bacteria was a reliable method to enhance the removals of phosphorus, nitrogen, and COD from domestic wastewater. PRACTITIONER POINTS: Alum-sludge ceramsite was a good substrate for phosphorus adsorption and denitrifying bacterial growth. There was 5.98 times more biofilm on sludge ceramsite than on commercial ceramsite The biofilm of denitrifying bacteria on sludge ceramsite was more stable. High removals of TP (98.6%), TN (90.1%) and COD (85.81%) were achieved.}, } @article {pmid30741656, year = {2019}, author = {Bayrak, O and Basmaci, I and Zer, Y and Kirkgoz Karabulut, E and Sen, H and Erturhan, S and Seckiner, I}, title = {Colonizations on biofilm layers of D-J catheters under sterile urine conditions.}, journal = {Archivos espanoles de urologia}, volume = {72}, number = {1}, pages = {75-79}, pmid = {30741656}, issn = {0004-0614}, mesh = {*Biofilms ; *Catheterization ; *Escherichia coli ; Humans ; *Urinary Catheters/microbiology ; }, abstract = {OBJECTIVE: To evaluate colonizations onbiofilm layers of Double J (D-J) catheters implanted forkidney stones or ureteral stones under sterile conditions.

METHODS: D-J catheters implanted between January2012 and February 2014 and removed in 0-90 days,were examined in microbiology laboratory prospectively.Fifty two patients divided into three groups regardingthe duration of the D-J catheters as; 0-30 days, 31-60days, 61-90 days. The colonization (≥1.000 colony)was reported after biofilm layer on D-J catheter was holdin culture media. The upper, middle and lower parts ofthe catheters were analyzed seperately.

RESULTS: Thirty five patients had symptomatic urinarytract infection or positive urine culture after implantationwere excluded from the study. Colonization on biofilm layer was detected in 11 patients (21.15%) [Coagulase-negative staphylococci (CNS): 3, Escherichia coli (E. coli): 3, Candida species (Candida spp.): 3, Klebsiella species (Klebsiella spp.): 2]. The rates of colonization according to the duration of the catheterization were; 12.5% in 0-30 days, 18.51% in 30-60 days, 29.4% in 60-90 days (Group 1 vs 2; .696 , group 1 vs group 3; .356 , group 2 vs group 3; .401). The rates of colonization according to the location of the catheter were; 100% in upper and lower parts, 54.4% in middle part (Group 1 vs 2; .011, group 1 vs group 3; , group 2 vs group 3; .011).

CONCLUSIONS: Colonization on catheters is possibleeven in the sterile urinary conditions according to thepresent findings. The risk of colonization increases 1.5times in 30-60 days and 2.5 times in 60-90 days comparedto the first 30 days. Besides the risk of colonizationincreases about 2 times in the convoluted edges ofthe catheter compared with the middle part. Thus, D-Jcatheter should be removed as soon as possible and therisk of colonization should be minimalized.}, } @article {pmid30741530, year = {2019}, author = {Diaz Perez, A and Kougl, K and Vasicek, TW and Liyanage, R and Lay, J and Stenken, JA}, title = {Microdialysis Sampling of Quorum Sensing Homoserine Lactones during Biofilm Formation.}, journal = {Analytical chemistry}, volume = {91}, number = {6}, pages = {3964-3970}, doi = {10.1021/acs.analchem.8b05168}, pmid = {30741530}, issn = {1520-6882}, mesh = {Bacteria/growth & development/*metabolism ; Biofilms/*growth & development ; Chromatography, Liquid ; Homoserine/*metabolism ; Lactones/*metabolism ; Mass Spectrometry ; Microdialysis/*methods ; *Quorum Sensing ; }, abstract = {Bacteria communicate chemically through a system called quorum sensing. In this work, microdialysis sampling procedures were optimized to collect quorum sensing molecules produced during in situ biofilm formation directly on the polymeric semipermeable membrane of the microdialysis probe. V. harveyi, a Gram-negative bacterium, was used as the model organism and releases variable chain length acylhomoserine lactones (AHLs) and acyl-oxohomoserine lactones (AOHLs) as signaling molecules during quorum sensing. Eliciting biofilm formation required coating fetal bovine serum onto the poly(ether sulfone) microdialysis membrane. Dialysates were collected in different experiments either during or after biofilm formation directly on a microdialysis probe. Continuous sampling of C4-AHL, C6-AHL, C8-AHL, C6-OXO-AHL, and C12-OXO-AHL was achieved over a period of up to 4 days. The AHLs and AOHLs in dialysates were concentrated with solid-phase extraction and quantified using LC-MS. Dialysate concentrations obtained for the AOHLs and AHLs ranged between 1 and 100 ppb (ng/mL) and varied between sampling days. This work demonstrates the initial use of microdialysis sampling to collect quorum sensing signaling chemicals during biofilm formation by a Gram-negative bacterial species.}, } @article {pmid30741037, year = {2019}, author = {Vadekeetil, A and Chhibber, S and Harjai, K}, title = {Efficacy of intravesical targeting of novel quorum sensing inhibitor nanoparticles against Pseudomonas aeruginosa biofilm-associated murine pyelonephritis.}, journal = {Journal of drug targeting}, volume = {27}, number = {9}, pages = {995-1003}, doi = {10.1080/1061186X.2019.1574802}, pmid = {30741037}, issn = {1029-2330}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Chitosan/chemistry ; Dextran Sulfate/chemistry ; Drug Delivery Systems ; Female ; Fluorescein-5-isothiocyanate/chemistry ; Mice ; Nanoparticles ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Pyelonephritis/drug therapy/microbiology ; Quorum Sensing/*drug effects ; Virulence Factors ; }, abstract = {Pseudomonas aeruginosa biofilm-associated pyelonephritis is a severe infection that can lead to mortality. There are no strategies that can effectively manage this infection since the pathogenesis is controlled by quorum sensing (QS) regulated virulence and recalcitrant biofilms. QS inhibitors (QSIs) are emerging therapeutics against such infections but are associated with cytotoxicity or low bioactivity. Hence, we developed novel quorum sensing inhibitor loaded nanoparticles (QSINPs) using the biopolymers, chitosan (CS) and dextran sulphate (DS) and were intravesically targeted against biofilm-associated murine pyelonephritis. The in-vivo targeting of QSINPs was confirmed by tracking the fluorescein isothiocyanate (FITC) tagged QSINPs in bladder and kidney of mice. On characterising, the QSINPs showed a size of 685.7 nm with a zeta potential of 37.9 and polydispersity index (PDI) of 0.5. Scanning electron microscopy (SEM) indicated spherical shape and bioactivity assays indicated QSI activity till 8 months. Fourier transform infra-red (FTIR) analysis indicated possibility of isothiocyanate bonding in CS with DS and with QSI. The QSINPs showed excellent in vitro antivirulence activity by reducing the virulence factors and biofilm of P. aeruginosa and in vivo therapeutic efficacy with ciprofloxacin (CIP). Hence, we propose a novel next-generation therapeutic and its appropriate targeting route against biofilm-associated pyelonephritis.}, } @article {pmid30740751, year = {2019}, author = {Marques, CNH and Nelson, SM}, title = {Pharmacodynamics of ciprofloxacin against Pseudomonas aeruginosa planktonic and biofilm-derived cells.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {350-359}, doi = {10.1111/lam.13126}, pmid = {30740751}, issn = {1472-765X}, support = {//HEFCEQR/ ; //BSAC project grant/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Ciprofloxacin/*pharmacology ; Microbial Sensitivity Tests ; Plankton/drug effects ; Pseudomonas aeruginosa/*drug effects/*growth & development ; }, abstract = {The influence of growth phase and state on the survival and recovery of Pseudomonas aeruginosa exposed to ciprofloxacin was investigated using batch culture grown planktonic cells and disaggregated biofilm populations. Biofilms were either nonantibiotic exposed or previously exposed to ciprofloxacin before disaggregation and subsequent challenge with ciprofloxacin. Viable counts showed that late stationary phase cells were tolerant to ciprofloxacin over 24 h exposure, while all other populations presented a biphasic killing pattern. In contrast, the metabolic activity of planktonic and biofilm-derived cells remained similar to controls during the initial 6 h of ciprofloxacin exposure, despite a significant reduction in viable cell numbers. A similar effect was observed when assessing the postantibiotic effect of 1 h ciprofloxacin exposure. Thus, although cell reduction occurred, the metabolic status of the cells remained unchanged. The recovery of disaggregated biofilm cells previously exposed to ciprofloxacin was significantly quicker than naïve biofilm cells, and this latter population's recovery was significantly slower than all planktonic populations. Results from this work have implications for our understanding of biofilm-related infections and their resilience to antimicrobial treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: Removal of biofilms from surfaces and infection sites via disaggregation and induction of dispersion may reverse their antibiotic tolerant state. However, little is known of the recovery of the cells upon disaggregation from biofilms. Driven by this gap in knowledge we quantified the effect of ciprofloxacin on disaggregated biofilms of Pseudomonas aeruginosa, including those previously exposed to ciprofloxacin. Our results provide further insight into bacterial resilience, regrowth, and antimicrobial efficacy, as reduction in cell viability does not directly correlate with the metabolic activity of bacteria at the time of the exposure to antimicrobials. Thus, despite a perceived reduction in viability, the potential for cell persistence and regrowth remains and recovery is quicker upon subsequent exposure to antimicrobial, supporting the increase in resilience and recurrence of infections.}, } @article {pmid30739982, year = {2018}, author = {Pasternak, G and Greenman, J and Ieropoulos, I}, title = {Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective.}, journal = {Journal of power sources}, volume = {400}, number = {}, pages = {392-401}, pmid = {30739982}, issn = {0378-7753}, abstract = {Appropriate inoculation and maturation may be crucial for shortening the startup time and maximising power output of Microbial Fuel Cells (MFCs), whilst ensuring stable operation. In this study we explore the relationship between electrochemical parameters of MFCs matured under different external resistance (Rext) values (50 Ω - 10 kΩ) using non-synthetic fuel (human urine). Maturing the biofilm under the lower selected Rext results in improved power performance and lowest internal resistance (Rint), whereas using higher Rext results in increased ohmic losses and inferior performance. When the optimal load is applied to the MFCs following maturity, dependence of microbial activity on original Rext values does not change, suggesting an irreversible effect on the biofilm, within the timeframe of the reported experiments. Biofilm microarchitecture is affected by Rext and plays an important role in MFC efficiency. Presence of water channels, EPS and precipitated salts is distinctive for higher Rext and open circuit MFCs. Correlation analysis reveals that the biofilm changes most dynamically in the first 5 weeks of operation and that fixed Rext lefts an electrochemical effect on biofilm performance. Therefore, the initial conditions of the biofilm development can affect its long-term structure, properties and activity.}, } @article {pmid30739073, year = {2019}, author = {Zhu, J and Liu, R and Cao, N and Yu, J and Liu, X and Yu, Z}, title = {Mycobacterial metabolic characteristics in a water meter biofilm revealed by metagenomics and metatranscriptomics.}, journal = {Water research}, volume = {153}, number = {}, pages = {315-323}, doi = {10.1016/j.watres.2019.01.032}, pmid = {30739073}, issn = {1879-2448}, mesh = {Biofilms ; *Drinking Water ; Metagenomics ; *Mycobacterium ; Water Supply ; }, abstract = {Mycobacteria represent one of the most persistent bacterial populations in drinking water distribution system (DWDS) biofilm communities; however, mycobacterial in situ metabolic profiles are largely unknown. In this study, the metabolic characteristics of mycobacteria in a household water meter biofilm were unveiled using a coupled metagenomic/metatranscriptomic approach. The water meter biofilm appeared to express nitrogenase genes (nifDKH) and a full complement of genes coding for several carbon-fixation pathways, especially the Calvin cycle, suggesting the CO2 sequestration and dinitrogen fixation potential of the biofilm. These findings indicate that it may be difficult to prevent the formation of DWDS biofilms simply by controlling the availability of organic carbon or nitrogen. The composite genome of mycobacteria (CG-M) was reconstructed based on the obtained omics data. CG-M shared similar genome phylogeny and virulence-factor profiles with Mycobacterium avium complex, suggesting that population CG-M might represent a member of mycobacteria with pathogenicity. According to the gene expression patterns, population CG-M showed the metabolic potential to assimilate CO2 via the Calvin cycle and/or anaplerotic reactions, and even to grow autotrophically with CO as the sole carbon and energy source. This suggests that organic carbon may not be a limiting factor for mycobacterial growth in DWDSs. Moreover, our results suggest that mycobacterial aromatic degradation is primarily achieved through the catechol meta-cleavage pathway, and biofilm mycobacteria could prefer phosphate as the phosphorus source.}, } @article {pmid30735953, year = {2019}, author = {Gong, CP and Luo, Y and Pan, YY}, title = {Novel synthesized zinc oxide nanoparticles loaded alginate-chitosan biofilm to enhanced wound site activity and anti-septic abilities for the management of complicated abdominal wound dehiscence.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {192}, number = {}, pages = {124-130}, doi = {10.1016/j.jphotobiol.2019.01.019}, pmid = {30735953}, issn = {1873-2682}, mesh = {*Abdominal Wound Closure Techniques ; Alginates ; Anti-Infective Agents, Local/*pharmacology ; Bacteria/drug effects ; *Biofilms ; Chitosan ; Humans ; Metal Nanoparticles/*chemistry ; Nanoparticles ; Surgical Wound Dehiscence/*drug therapy ; Wound Healing/*drug effects ; Zinc Oxide/chemistry ; }, abstract = {Wound dehiscence is a surgical complication and its management is inevitable because 25% to 35% of patients suffered from post laparotomy wound dehiscence. The excellent biodegradability and biocompatibility of chitosan and alginate have provided ample space for future developments in biomedical applications. Hence, the present work is directed towards the synthesis of robust biofilm made up of chitosan (CS), zinc oxide (ZnO) nanoparticles and Alginate (Alg). Chitosan and alginate were used for their pore forming ability, and ZnO is for its antibacterial action. The proposed biofilm was characterized with different characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy, UV-vis spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron microscopy (TEM) analyses. FTIR results inferred the strong interaction between the three components. The surface morphology of ZnO-CS/Alg. biofilm was exhibited as the spherical shaped nanoparticles which are firmly anchored on the polymer matrix. TEM analysis also confirmed the formation of biofilm. The XRD analysis confirmed the presence of ZnO in the biopolymer. The line broadening suggests that the crystallize size is in few nanometers. The average crystallite size was estimated as 50 nm using Scherrer formula. The antibacterial activity of the biofilm was successfully established against bacterial pathogens. Therefore, the developed materials have a potential play as antimicrobial role for the abdominal wound healing and biomedical fields.}, } @article {pmid30735206, year = {2019}, author = {Ding, Y and Zhou, Y and Yao, J and Xiong, Y and Zhu, Z and Yu, XY}, title = {Molecular evidence of a toxic effect on a biofilm and its matrix.}, journal = {The Analyst}, volume = {144}, number = {8}, pages = {2498-2503}, doi = {10.1039/c8an02512f}, pmid = {30735206}, issn = {1364-5528}, mesh = {Biofilms/*drug effects ; Lab-On-A-Chip Devices ; Microfluidic Analytical Techniques/instrumentation/methods ; Potassium Dichromate/*toxicity ; Shewanella/classification/*physiology ; Spectrometry, Mass, Secondary Ion/methods ; }, abstract = {Shewanella oneidensis MR-1 wild-type and a hyper-adhesive mutant CP2-1-S1 are used as model organisms and Cr(vi) is selected as a toxic chemical to study biofilm and toxic chemical interactions. Biofilms are cultured in a microfluidic device for in situ time-of-flight secondary ion mass spectrometry imaging. This approach is viable for studying biofilms' responses to antimicrobial resistance.}, } @article {pmid30735113, year = {2019}, author = {Staneviciute, E and Na'amnih, W and Kavaliauskas, P and Prakapaite, R and Ridziauskas, M and Kevlicius, L and Kirkliauskiene, A and Zabulis, V and Urboniene, J and Triponis, V}, title = {New in vitro model evaluating antiseptics' efficacy in biofilm-associated Staphylococcus aureus prosthetic vascular graft infection.}, journal = {Journal of medical microbiology}, volume = {68}, number = {3}, pages = {432-439}, doi = {10.1099/jmm.0.000939}, pmid = {30735113}, issn = {1473-5644}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Humans ; Imines ; Povidone-Iodine/pharmacology ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/prevention & control ; Pyridines/pharmacology ; Staphylococcal Infections/prevention & control ; Staphylococcus aureus/*drug effects ; }, abstract = {PURPOSE: To develop a new in vitro model of prosthetic vascular graft infection (PVGI) and evaluate antimicrobial and biofilm-disrupting efficacy of 0.1% octenidine dihydrochloride, 10% povidone-iodine and 0.02% chlorhexidine digluconate against biofilm-producing Staphylococcus aureus (S. aureus).

METHODOLOGY: The effect of antiseptics on the microscopic integrity and antimicrobial effect on S. aureus biofilms was tested by growing biofilms on glass coverslips, in the modified Lubbock chronic wound pathogenic biofilm (LCWPB) model and on the surface of vascular grafts using qualitive and quantitative methods as well as by scanning electron microscopy (SEM).

RESULTS: Chlorhexidine worked best on destroying the integrity of S. aureus biofilms (P=0.002). In the LCWPB model, octenidine and povidone-iodine eradicated all S. aureus colonies (from 1.79 × 10[9]  c.f.u. ml[-1] to 0). In the newly developed PVGI model, the grafts were successfully colonized with biofilms as seen in SEM images. All antiseptics demonstrated significant antimicrobial efficacy, decreasing colony counts by seven orders of magnitude (P=0.002). Octenidine was superior to povidone-iodine (P=0.009) and chlorhexidine (P=0.041).

CONCLUSION: We implemented an innovative in vitro model on S. aureus biofilms grown in different settings, including a clinically challenging situation of PVGI. The strongest antimicrobial activity against S. aureus biofilms, grown on prosthetic vascular grafts, was showed by 0.1% octenidine dihydrochloride. We suggest that combinational therapy of antiseptics between chlorhexidine with either povidone-iodine or octenidine dihydrochloride should be tested in further experiments. Despite the need of further studies, our findings of these in vitro experiments will assist the management of vascular graft infection in clinical cases.}, } @article {pmid30734662, year = {2020}, author = {Ashrafi, E and Allahyari, E and Torresi, E and Andersen, HR}, title = {Effect of slow biodegradable substrate addition on biofilm structure and reactor performance in two MBBRs filled with different support media.}, journal = {Environmental technology}, volume = {41}, number = {21}, pages = {2750-2759}, doi = {10.1080/09593330.2019.1581261}, pmid = {30734662}, issn = {1479-487X}, mesh = {*Biofilms ; Biomass ; Bioreactors ; *Nitrification ; Nitrogen ; Waste Disposal, Fluid ; }, abstract = {In this study, two moving-bed biofilm reactors (MBBR1 and MBBR2) filled with different size of carrier media (Kaldnes K1 and Kaldnes K1 micro, respectively) were subjected to soluble (sugar and sodium acetate (Ac)) substrate and mixture of soluble and particulate (particulate potato starch (PS)) substrate in a very high organic loading rate (12 kgCOD/m[3]·d) at different temperatures (26 and 15°C, in MBBR1 and MBBR2, respectively). The effects of carrier type and substrate on biofilm structure and reactor performance have been studied. Starch was removed by adsorption at the biofilm surface and hydrolyzed which caused substrate gradient in MBBR1, however, hydrolyzed uniformly within biofilm in MBBR2. The biofilm of MBBR1 was irregular due to filamentous structure growth due to the substrate gradient, while, it was regular in MBBR2 due to uniform distribution of substrate. The performance of both MBBRs in ammonium, COD and TN removal decreased significantly when the amount of small particles in the reactor increased owing to feeding by starch, which led to biomass density decline. The type of media affected the quantity and distribution of attached biomass, which in turn influenced the activity of specific microbial functional groups in the biofilm. The biofilm in MBBR2 was thicker and consequently nitrogen removal by denitrification was much higher. The lower temperature did not affect negatively the reactor performance in MBBR2.}, } @article {pmid30733843, year = {2019}, author = {Takenaka, S and Ohsumi, T and Noiri, Y}, title = {Evidence-based strategy for dental biofilms: Current evidence of mouthwashes on dental biofilm and gingivitis.}, journal = {The Japanese dental science review}, volume = {55}, number = {1}, pages = {33-40}, pmid = {30733843}, issn = {1882-7616}, abstract = {Therapeutic mouthwash (MW) is an adjunctive tool along with a regular oral hygiene routine of daily tooth brushing and daily flossing. Previous systematic reviews have demonstrated that it is effective against dental biofilm and gingival inflammation, for prevention of dental caries, and for managing one's bad breath condition according to the active ingredients. MWs prevent the microorganisms from bacterial adhesion that corresponds to the initial step in biofilm formation. This review summarized the current state of evidence such as anti-biofilm, anti-gingivitis and cariostatic properties of MWs by evaluating systematic reviews from the past six years. The anti-biofilm property has been proven to be effective, with strong evidence of three main clinical efficacies. The most commonly studied active agent was chlorhexidine gluconate (CHX), followed by essential oil (EO) and cetylpyridinium chloride. All the systematic reviews are in complete agreement that CHX and EO provide statistically significant improvements in terms of plaque and gingival indices. These effects have held up over the years as the number of studies has increased. While the use of fluoride MW is proven to be effective in improving the oral health of both children and adults, the quality of evidence is still regarded as low.}, } @article {pmid30732464, year = {2018}, author = {Etim, IN and Wei, J and Dong, J and Xu, D and Chen, N and Wei, X and Su, M and Ke, W}, title = {Mitigation of the corrosion-causing Desulfovibrio desulfuricans biofilm using an organic silicon quaternary ammonium salt in alkaline media simulated concrete pore solutions.}, journal = {Biofouling}, volume = {34}, number = {10}, pages = {1121-1137}, doi = {10.1080/08927014.2018.1547377}, pmid = {30732464}, issn = {1029-2454}, mesh = {Biofilms/*drug effects/growth & development ; *Corrosion ; Culture Media ; Desulfovibrio desulfuricans/*growth & development ; Models, Theoretical ; Organosilicon Compounds/*pharmacology ; Quaternary Ammonium Compounds/*pharmacology ; Solutions ; *Steel/chemistry ; Surface Properties ; }, abstract = {Organic silicon quaternary ammonium salt (OSA), an environmentally friendly naturally occurring chemical, was used as a bacteriostatic agent against sulphate-reducing bacteria (SRB) on a 20SiMn steel surface in simulated concrete pore solutions (SCP). Four different media were used: No SRB (NSRB), No SRB and OSA (NSRB + OSA), With SRB (WSRB), With SRB and OSA (WSRB + OSA). After biofilm growth for 28 days, optimized sessile SRB cells survived at the high pH of 11.35 and as a result these cells caused the breakdown of the passive film due to the metabolic activities of the SRB. Corrosion prevention results showed that the OSA was effective in mitigating the growth of the sessile SRB cells and reduced corrosion in the SCP. These results were further confirmed by scanning electron microscope images, energy dispersive X-ray analysis, confocal-laser scanning microscopy, X-ray photoelectron spectroscopy and corrosion testing using electrochemical analysis.}, } @article {pmid30731369, year = {2019}, author = {Tang, B and Gong, T and Zhou, X and Lu, M and Zeng, J and Peng, X and Wang, S and Li, Y}, title = {Deletion of cas3 gene in Streptococcus mutans affects biofilm formation and increases fluoride sensitivity.}, journal = {Archives of oral biology}, volume = {99}, number = {}, pages = {190-197}, doi = {10.1016/j.archoralbio.2019.01.016}, pmid = {30731369}, issn = {1879-1506}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Biomass ; CRISPR-Associated Proteins/*genetics ; CRISPR-Cas Systems ; Coculture Techniques ; DNA Helicases ; Dental Caries ; Drug Resistance, Bacterial/genetics ; Drug Tolerance ; Escherichia coli Proteins ; Fluorides/*pharmacology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; In Situ Hybridization, Fluorescence ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Streptococcus mutans/*drug effects/*genetics/*metabolism ; Streptococcus sanguis/physiology ; Transcriptome ; Virulence/genetics ; }, abstract = {OBJECTIVE: The goal of this study was to analyze the impact of cas3 gene on the biofilm formation and virulence gene expression in S. mutans, since our previous studies have found a connection between CRISPR/Cas systems and biofilm formation in S. mutans.

METHODS: The cas3 gene in-frame deletion strains of S. mutans UA159 was constructed by a two-step transformation procedure and the cas3 mutant strain was complemented in trans. The biofilm biomass was measured by crystal violet staining, and the synthesis of exopolysaccharides (EPS) was measured by the anthrone-sulfuric method. Biofilm analysis and structural imaging was using confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) assays. The fluorescence in situ hybridization (FISH) was used to analyze the spatiotemporal interactions between S. mutans and Streptococcus sanguinis. Fluoride sensitivity was determined using fluoride tolerance assays. The expression of biofilm formation related genes was evaluated by qRT-PCR.

RESULTS: Our results showed that S. mutans cas3 deletion strain formed less biofilm and became less competitive when it was co-cultured with S. sanguinis under fluoride treatment. The expression levels of virulence genes including vicR, gtfC, smu0630 and comDE were significantly downregulated.

CONCLUSIONS: The cas3 gene in S. mutans could regulate biofilm formation and fluoride resistance, consequently affecting S. mutans competitiveness in a dual-species biofilm model under fluoride treatment. These results also provide a potential strategy for enhancing fluoride specificity, with cas3 gene as a potential genetic target in the modulation of oral microecology and the treatment of dental caries.}, } @article {pmid30731188, year = {2019}, author = {Mohammadi, M and Masoumipour, F and Hassanshahian, M and Jafarinasab, T}, title = {Study the antibacterial and antibiofilm activity of Carum copticum against antibiotic-resistant bacteria in planktonic and biofilm forms.}, journal = {Microbial pathogenesis}, volume = {129}, number = {}, pages = {99-105}, doi = {10.1016/j.micpath.2019.02.002}, pmid = {30731188}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Carum/*chemistry ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; }, abstract = {OBJECTIVES: Microbial biofilms has attracted interest in the recent years because they has become the most important cause of nosocomial infections. This study was aimed to examine the antibacterial activities of Carum copticum extracts on the development of microbial biofilms and planktonic form of six pathogenic bacteria.

METHODS: Antimicrobial activity of the crude extracts against the planktonic form of six pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii and Klebsiella pneumonia was evaluated by using the disc diffusion method. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values was determined by macro-broth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. The chemical composition of the herbal extract was identified by GC-MS.

RESULTS: According to disc diffusion test (MIC and MBC) the ability of C. copticum extracts for inhibition of bacteria in planktonic form was confirmed. The best inhibitory effect of this plant on S. aureus and low inhibitory effect on A. baumannii in planktonic forms were observed. These extracts were efficient to inhibit biofilm structures and concentration of each extract has direct relation with inhibitory effect. The maximum and minimum inhibitory effects of C. copticum methanolic extract on biofilm formation were observed on A. baumannii (98%) and K. pneumoniae (19%) respectively.

CONCLUSION: The GC-MS analysis revealed that five active compounds were present in the extract of this plant. Data obtained, suggested that the C. copticum extracts applied as antimicrobial agents against these pathogens particularly in biofilm making.}, } @article {pmid30729077, year = {2019}, author = {Prasad, A and Devi, AT and Prasad, MNN and Zameer, F and Shruthi, G and Shivamallu, C}, title = {Phyto anti-biofilm elicitors as potential inhibitors of Helicobacter pylori.}, journal = {3 Biotech}, volume = {9}, number = {2}, pages = {53}, pmid = {30729077}, issn = {2190-572X}, abstract = {Helicobacter pylori (H. pylori) infection is a global public health concern. Due to its high adaptability in various adverse environments (temperature, pH, adhesion, phenotypic forms), targeting the bacterium is quite challenging. Moreover, due to its high persistence, decreased patience compliance and emerging antibiotic resistance, researchers have been forced to search for novel candidates with lesser or no side effects. Hence, in the current study, phytobioactives have been screened for its anti-biofilm attributes against H.pylori. Gastric biopsy samples have been screened using confirmatory techniques (microbiological, biochemical and molecular) for their virulent and non-virulent biomarkers. Physico-nutritive parameters were standardized. H. pylori biofilms were assessed using microtitre plate assay. Biofilms' biomass and exopolysaccharide have been evaluated using crystal violet and ruthenium red staining, respectively. Anti-biofilm screening was performed using potent aqueous phytochemicals namely Acorus calamus, Colocasia esculenta and Vitex trifolia. The results indicated the confluent growth of the H. pylori biofilms confirmed through genotyping and grew best at 37 °C for 72 h at a pH of 7.5 on polystyrene plates. Further, among the phytochemicals tested, Acorus calamus exhibited the highest H. pylori anti-biofilm activity via a dose-dependent pattern. The overall observations of the study will pave way for newer approaches to understand and combat bacterial pathogenesis and will contribute towards better health and hygiene.}, } @article {pmid30728810, year = {2019}, author = {Yang, Y and Luo, M and Zhou, H and Li, C and Luk, A and Zhao, G and Fung, K and Ip, M}, title = {Role of Two-Component System Response Regulator bceR in the Antimicrobial Resistance, Virulence, Biofilm Formation, and Stress Response of Group B Streptococcus.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {10}, pmid = {30728810}, issn = {1664-302X}, abstract = {Group B Streptococcus (GBS; Streptococcus agalactiae) is a leading cause of sepsis in neonates and pregnant mothers worldwide. Whereas the hyper-virulent serogroup III clonal cluster 17 has been associated with neonatal disease and meningitis, serogroup III ST283 was recently implicated in invasive disease among non-pregnant adults in Asia. Here, through comparative genome analyses of invasive and non-invasive ST283 strains, we identified a truncated DNA-binding regulator of a two-component system in a non-invasive strain that was homologous to Bacillus subtilis bceR, encoding the bceRSAB response regulator, which was conserved among GBS strains. Using isogenic knockout and complementation mutants of the ST283 strain, we demonstrated that resistance to bacitracin and the human antimicrobial peptide cathelicidin LL-37 was reduced in the ΔbceR strain with MICs changing from 64 and 256 μg/ml to 0.25 and 64 μg/ml, respectively. Further, the ATP-binding cassette transporter was upregulated by sub-inhibitory concentrations of bacitracin in the wild-type strain. Upregulation of dltA in the wild-type strain was also observed and thought to explain the increased resistance to antimicrobial peptides. DltA, an enzyme involved in D-alanylation during the synthesis of wall teichoic acids, which mediates reduced antimicrobial susceptibility, was previously shown to be regulated by the bceR-type regulator in Staphylococcus aureus. In a murine infection model, we found that the ΔbceR mutation significantly reduced the mortality rate compared to that with the wild-type strain (p < 0.01). Moreover, this mutant was more susceptible to oxidative stress compared to the wild-type strain (p < 0.001) and was associated with reduced biofilm formation (p < 0.0001). Based on 2-DGE and mass spectrometry, we showed that downregulation of alkyl hydroperoxide reductase (AhpC), a Gls24 family stress protein, and alcohol dehydrogenase (Adh) in the ΔbceR strain might explain the attenuated virulence and compromised stress response. Together, we showed for the first time that the bceR regulator in GBS plays an important role in bacitracin and antimicrobial peptide resistance, virulence, survival under oxidative stress, and biofilm formation.}, } @article {pmid30728626, year = {2019}, author = {Gupta, K and Singh, SP and Manhar, AK and Saikia, D and Namsa, ND and Konwar, BK and Mandal, M}, title = {Inhibition of Staphylococcus aureus and Pseudomonas aeruginosa Biofilm and Virulence by Active Fraction of Syzygium cumini (L.) Skeels Leaf Extract: In-Vitro and In Silico Studies.}, journal = {Indian journal of microbiology}, volume = {59}, number = {1}, pages = {13-21}, pmid = {30728626}, issn = {0046-8991}, abstract = {Syzygium cumini L. Skeels (Myretacae family) is a native plant of the Indian subcontinent which has wide socio-economical importance and is well known for its ant diabetic activity. The present study aimed to investigate the antibiofilm activity of purified fraction (EA) from S. cumini leaf extract against P. aeruginosa and S. aureus. The EA did not show any effect on growth of P. aeruginosa and S. aureus at the concentration of 900 µg/ml. At this concentration EA showed biofilm inhibition up to 86 ± 1.19% (***P < 0.0001) and 86.40 ± 1.19% (***P < 0.0001) in P. aeruginosa and S. aureus respectively. SEM examination also confirmed the reduction in biofilm formation. Further EA also disrupted some virulence phenotypes in P. aeruginosa and S. aureus. Bioactive compounds detected by GC-MS showed their possible molecular interaction with RhlG/NADP active-site complex (PDB ID: 2B4Q), LasR-TP4 complex (PDB ID: 3JPU) and Pseudaminidase (PDB ID: 2W38) from P. aeruginosa. The in vitro biofilm inhibition, virulence factor inhibition and the mode of interaction of bioactive components in Syzygium cumini with QS proteins of bacteria reported in this study might be an affordable and effective alternative method of controlling quorum sensing/biofilm-associated infections.}, } @article {pmid30727772, year = {2019}, author = {Czerwonka, G and Gmiter, D and Guzy, A and Rogala, P and Jabłońska-Wawrzycka, A and Borkowski, A and Cłapa, T and Narożna, D and Kowalczyk, P and Syczewski, M and Drabik, M and Dańczuk, M and Kaca, W}, title = {A benzimidazole-based ruthenium(IV) complex inhibits Pseudomonas aeruginosa biofilm formation by interacting with siderophores and the cell envelope, and inducing oxidative stress.}, journal = {Biofouling}, volume = {35}, number = {1}, pages = {59-74}, doi = {10.1080/08927014.2018.1564818}, pmid = {30727772}, issn = {1029-2454}, mesh = {Animals ; Benzimidazoles/*pharmacology ; Binding Sites ; Biofilms/*drug effects ; Cattle ; Cell Wall/drug effects ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Electron, Scanning ; Models, Theoretical ; Oligopeptides ; *Oxidative Stress ; Plasmids/metabolism ; Pseudomonas Infections/prevention & control ; Pseudomonas aeruginosa/*drug effects/physiology ; Ruthenium/*pharmacology ; Serum Albumin, Bovine/chemistry ; Siderophores/*chemistry ; }, abstract = {Pseudomonas aeruginosa biofilm-associated infections are a serious medical problem, and new compounds and therapies acting through novel mechanisms are much needed. Herein, the authors report a ruthenium(IV) complex that reduces P. aeruginosa PAO1 biofilm formation by 84%, and alters biofilm morphology and the living-to-dead cell ratio at 1 mM concentration. Including the compound in the culture medium altered the pigments secreted by PAO1, and fluorescence spectra revealed a decrease in pyoverdine. Scanning electron microscopy showed that the ruthenium complex did not penetrate the bacterial cell wall, but accumulated on external cell structures. Fluorescence quenching experiments indicated strong binding of the ruthenium complex to both plasmid DNA and bovine serum albumin. Formamidopyrimidine DNA N-glycosylase (Fpg) protein digestion of plasmid DNA isolated after ruthenium(IV) complex treatment revealed the generation of oxidative stress, which was further proved by the observed upregulation of catalase and superoxide dismutase gene expression.}, } @article {pmid30727758, year = {2019}, author = {Shah, S and Gaikwad, S and Nagar, S and Kulshrestha, S and Vaidya, V and Nawani, N and Pawar, S}, title = {Biofilm inhibition and anti-quorum sensing activity of phytosynthesized silver nanoparticles against the nosocomial pathogen Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {35}, number = {1}, pages = {34-49}, doi = {10.1080/08927014.2018.1563686}, pmid = {30727758}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Chromobacterium/physiology ; Cross Infection/microbiology ; Gentian Violet/chemistry ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pancreatic Elastase/chemistry ; Phytochemicals/pharmacology ; Piper betle/chemistry ; Plant Extracts/chemistry/pharmacology ; Plant Leaves/chemistry ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Silver/*chemistry ; Virulence Factors/metabolism ; }, abstract = {Quorum sensing (QS), the communication signaling network, regulates biofilm formation and several virulence factors in Pseudomonas aeruginosa PAO1, a nosocomial opportunistic pathogen. QS is considered to be a challenging target for compounds antagonistic to virulent factors. Biologically synthesized silver nanoparticles (AgNPs) are reported as anti-QS and anti-biofilm drugs against bacterial infections. The present study reports on the synthesis and characterization of Piper betle (Pb) mediated AgNPs (Pb-AgNPs). The anti-QS activity of Pb-AgNPs against Chromobacterium violaceum and the potential effect of Pb-AgNPs on QS-regulated phenotypes in PAO1 were studied. FTIR analysis exhibited that Pb-AgNPs had been capped by phytochemical constituents of Pb. Eugenol is one of the active phenolic phytochemicals in Pb leaves, therefore molecular docking of eugenol-conjugated AgNPs on QS regulator proteins (LasR, LasI and MvfR) was performed. Eugenol-conjugated AgNPs showed considerable binding interactions with QS-associated proteins. These results provide novel insights into the development of phytochemically conjugated nanoparticles as promising anti-infective candidates.}, } @article {pmid30726061, year = {2019}, author = {Liu, F and He, D and Yu, Y and Cheng, L and Zhang, S}, title = {Quaternary Ammonium Salt-Based Cross-Linked Micelles to Combat Biofilm.}, journal = {Bioconjugate chemistry}, volume = {30}, number = {3}, pages = {541-546}, doi = {10.1021/acs.bioconjchem.9b00010}, pmid = {30726061}, issn = {1520-4812}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Humans ; Micelles ; Nanoparticles/chemistry ; Quaternary Ammonium Compounds/*chemistry/*pharmacology ; Salts/chemistry/pharmacology ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Due to self-produced extracellular polymeric substances (EPS), biofilms are hard to eradicate by common antimicrobials. Herein, a new quaternary ammonium salt based cross-linked micelle (QAS@CM) was created to combat biofilms. The QAS@CM adsorbed first onto the biofilm surface through multicharged interaction, then penetrated the EPS in the form of nanoparticles and diffused throughout the films. By responding to the biofilm acid/lipase microenvironment, these nanoparticles would further break into quaternary ammonium oligomers and act as the polyvalent inhibitors to effectively destroy the established biofilm and kill the corresponding bacteria within it.}, } @article {pmid30725258, year = {2019}, author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L}, title = {Effects of cerium oxide nanoparticles on bacterial growth and behaviors: induction of biofilm formation and stress response.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {9}, pages = {9293-9304}, pmid = {30725258}, issn = {1614-7499}, support = {KYCX18_0636//the Postgraduate Research & Practice Innovation Program of Jiangsu Province/ ; No.51722902//the National Natural Science Funds for Excellent Young Scholar/ ; No.51421006//the National Natural Science Funds for Creative Research Groups of China/ ; No. 91647206//the Key Program of National Natural Science Foundation of China/ ; BK20160038//the Outstanding Youth Fund of Natural Science Foundation of Jiangsu, China/ ; 2018B671X14//the Fundamental Research Funds for the Central Universities/ ; }, mesh = {Bacteria/*drug effects/metabolism ; Biofilms/*drug effects ; Cerium/*toxicity ; Metal Nanoparticles ; Nanoparticles/chemistry/*toxicity ; Oxidative Stress/drug effects ; Quorum Sensing ; Reactive Oxygen Species/metabolism ; }, abstract = {In this paper, the effects of cerium oxide nanoparticles (CeO2 NPs) on the group bacterial behaviors were elaborated. After 36-h cultivation, the biofilm biomass was enhanced by the sub-lethal concentrations of 0.5 and 2 mg/L CeO2 NP exposure. Meanwhile, the promoted production of total amino acids in microbes further resulted in the increased surface hydrophobicity and percentage aggregation. To resist the CeO2 NPs stress, the biofilm exhibited a double-layer microstructure, with the protein (PRO) and living cells occupying the bottom, the polysaccharide (PS), and dead cells dominating the top. The bacterial diversity was highly suppressed and Citrobacter and Pseudomonas from the phylum of γ-Proteobacteria strongly dominated the biofilm, indicating the selective and enriched effects of CeO2 NPs on resistant bacteria. The stimulated inherent resistance of biofilm was reflected by the reduced adenosine triphosphate (ATP) content after 4 h exposure. The increased levels of reactive oxygen species (ROS) in the treatments of 8 h CeO2 NP exposure led to the upregulated quorum sensing signals of acylated homoserine lactone (AHL) and autoinducer 2 (AI-2), beneficial to mitigating the environmental disturbance of CeO2 NPs. These results provide evidences for the accelerating effects of CeO2 NPs on biofilm formation through oxidative stress, which expand the understanding of the ecological effects of CeO2 NPs.}, } @article {pmid30724702, year = {2020}, author = {Enaime, G and Baçaoui, A and Yaacoubi, A and Berzio, S and Wichern, M and Lübken, M}, title = {Packed-bed biofilm reactor for semi-continuous anaerobic digestion of olive mill wastewater: performances and COD mass balance analysis.}, journal = {Environmental technology}, volume = {41}, number = {20}, pages = {2657-2669}, doi = {10.1080/09593330.2019.1578830}, pmid = {30724702}, issn = {1479-487X}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Methane ; *Olea ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {In the present study, the treatability of olive mill wastewater (OMWW) using an anaerobic fixed bed biofilm reactor packed with granular activated carbon (GAC) and inoculated with non-acclimated biomass was performed in a semi-continuous mode under mesophilic conditions. Three organic loading rates (OLR) varied from 0.94 to 2.81 g COD/(L d) were applied. The results of batch adsorption tests on GAC and the experimental data from PBBR-GAC operation were used to set up a COD mass balance in order to investigate the effect of adsorption on the COD removal during the three anaerobic treatment steps. Despite the slight accumulation of volatile fatty acids (VFAs) during the second and the third steps, between 735 and 1135 mg COD/L (as acetic acid), a stable environment for methanogens was maintained for a period of 104 days. During the three steps, degradation levels were up to 80% of COD and 85% of phenolic compounds. An averaged specific biogas production of 1.77 LN/d and a methane (CH4) concentration of about 60%, corresponding to a CH4 yield of 0.31 L CH4produced/g CODdepleted, were reached at an OLR of 2.81 g COD/(L d). The results show that the COD mass balance was not closed during the first two steps, while in the third step, it could be around 96%. This finding suggests that the adsorption of organic substances on activated carbon occur just during the two first steps, while at 2.81 g COD/(L d) OLR no adsorption is occurring and the introduced COD becomes completely available for CH4 production.}, } @article {pmid30719720, year = {2019}, author = {Ramirez, T and Shrestha, A and Kishen, A}, title = {Inflammatory potential of monospecies biofilm matrix components.}, journal = {International endodontic journal}, volume = {52}, number = {7}, pages = {1020-1027}, doi = {10.1111/iej.13093}, pmid = {30719720}, issn = {1365-2591}, support = {//University of Toronto/ ; }, mesh = {*Biofilms ; Enterococcus faecalis ; *Extracellular Polymeric Substance Matrix ; Macrophages ; Pseudomonas aeruginosa ; }, abstract = {AIM: To assess the inflammatory potential of biofilm matrix constituents of Enterococcus faecalis and Pseudomonas aeruginosa monospecies biofilms on macrophages.

METHODOLOGY: In vitro biofilms of E. faecalis and P. aeruginosa were grown (7 days) in aerobic and anaerobic conditions. The biofilm matrix components: exopolysaccharides (EPS) and extracellular DNA (eDNA) were extracted and quantified. The inflammatory potential of EPS and eDNA was assessed on macrophage cell lines (RAW 267.4) using nitric oxide (NO), and enzyme-linked immunosorbent assay for tumour necrosis factor (TNF-α) and interleukin-6 (IL-6) expressions. LPS from P. aeruginosa and planktonic bacteria were positive controls. One-way analysis of variance and the Tukey post hoc test were used for statistical analysis.

RESULTS: Extracted EPS from both biofilm strains was associated with higher levels than eDNA in both growth conditions (P < 0.05). The biofilm components had less inflammatory potential compared to planktonic bacteria and LPS. EPS produced higher levels of inflammatory response compared to eDNA for both strains (P < 0.05). IL-6 and TNF-α, and NO expression showed no difference for E. faecalis EPS (P ≥ 0.05). In contrast, P. aeruginosa EPS and eDNA had significant levels of IL-6 compared to TNF-α and NO (P < 0.05).

CONCLUSIONS: Monospecies biofilm matrix EPS and eDNA from the bacterial strains tested had the ability to induce a low-grade inflammatory response when compared to planktonic bacteria and LPS. This study highlights the potential of biofilm matrix/components, devoid of bacteria to induce low-grade chronic inflammation.}, } @article {pmid30719328, year = {2018}, author = {Frickmann, H and Klenk, C and Warnke, P and Redanz, S and Podbielski, A}, title = {Influence of Probiotic Culture Supernatants on In Vitro Biofilm Formation of Staphylococci.}, journal = {European journal of microbiology & immunology}, volume = {8}, number = {4}, pages = {119-127}, pmid = {30719328}, issn = {2062-509X}, abstract = {BACKGROUND: The effects of cell-free culture supernatants of probiotic Lactobacillus rhamnosus GG and Streptococcus salivarius K12 on replication and biofilm forming of Staphylococcus aureus and S. epidermidis were assessed in vitro.

METHODS: S. aureus and S. epidermidis strains were exposed to cell-free culture supernatants of L. rhamnosus GG and S. salivarius K12 at different concentrations starting at 0, 4, and 24 h after the onset of incubation. Bacterial amplification was measured on microplate readers, as well as biofilm growth after safranine staining. Scanning electron microscopy was performed for visualization of biofilm status.

RESULTS: The S. salivarius K12 culture supernatant not only reduced or prevented the formation and maturation of fresh biofilms but even caused a reduction of preformed S. epidermidis biofilms. The L. rhamnosus GG culture supernatant did not show clear inhibitory effects regardless of concentration or time of addition of supernatant, and even concentration-depending promotional effects on the planktonic and biofilm growth of S. aureus and S. epidermidis were observed.

CONCLUSION: In particular, the inhibitory effects of the S. salivarius K12 culture supernatant on the formation of staphylococcal biofilms are of potential relevance for biofilm-associated diseases and should be further assessed by in vivo infection models.}, } @article {pmid30718527, year = {2019}, author = {Miao, J and Lin, S and Soteyome, T and Peters, BM and Li, Y and Chen, H and Su, J and Li, L and Li, B and Xu, Z and Shirtliff, ME and Harro, JM}, title = {Biofilm Formation of Staphylococcus aureus under Food Heat Processing Conditions: First Report on CML Production within Biofilm.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {1312}, pmid = {30718527}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; *Food Handling ; *Food Microbiology ; Hydrogen-Ion Concentration ; Staphylococcus aureus/*physiology/ultrastructure ; Temperature ; }, abstract = {This study aimed to evaluate the Staphylococcus aureus biofilm formation and Nε-carboxymethyl-lysine generation ability under food heat processing conditions including pH (5.0-9.0), temperature (25 °C, 31 °C, 37 °C, 42 °C and 65 °C), NaCl concentration (10%, 15% and 20%, w/v) and glucose concentration (0.5%, 1%, 2%, 3%, 5%, 10%, w/v). S. aureus biofilm genetic character was obtained by PCR detecting atl, ica operon, sasG and agr. Biofilm biomass and metabolic activity were quantified with crystal violet and methyl thiazolyl tetrazolium staining methods. S. aureus biofilm was sensitive to food heat processing conditions with 37 °C, pH 7.0, 2% glucose concentration (w/v) and 10% NaCl concentration (w/v) were favorable conditions. Besides, free and bound Nε-carboxymethyl-lysine level in weak, moderate and strong biofilm were detected by optimized high performance liquid chromatography tandem mass spectrometry. Nε-carboxymethyl-lysine level in S. aureus biofilm possessed a significant gap between strong, moderate and weak biofilm strains. This investigation revealed the biological and chemical hazard of Staphylococcus aureus biofilm to food processing environment.}, } @article {pmid30718304, year = {2019}, author = {Kobayashi, K}, title = {Inactivation of cysL Inhibits Biofilm Formation by Activating the Disulfide Stress Regulator Spx in Bacillus subtilis.}, journal = {Journal of bacteriology}, volume = {201}, number = {8}, pages = {}, pmid = {30718304}, issn = {1098-5530}, mesh = {Bacillus subtilis/*enzymology/genetics/*growth & development ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression ; *Gene Expression Regulation, Bacterial ; Transcription Factors/genetics/*metabolism ; }, abstract = {Bacillus subtilis forms biofilms in response to internal and external stimuli. I previously showed that the cysL deletion mutant was defective in biofilm formation, but the reason for this remains unidentified. CysL is a transcriptional activator of the cysJI operon, which encodes sulfite reductase, an enzyme involved in cysteine biosynthesis. Decreased production of sulfite reductase led to biofilm formation defects in the ΔcysL mutant. The ΔcysL mutation was suppressed by disrupting cysH operon genes, whose products function upstream of sulfite reductase in the cysteine biosynthesis pathway, indicating that defects in cysteine biosynthesis were not a direct cause for the defective biofilm formation observed in the ΔcysL mutant. The cysH gene encodes phosphoadenosine phosphosulfate reductase, which requires a reduced form of thioredoxin (TrxA) as an electron donor. High expression of trxA inhibited biofilm formation in the ΔcysL mutant but not in the wild-type strain. Northern blot analysis showed that trxA transcription was induced in the ΔcysL mutant in a disulfide stress-induced regulator Spx-dependent manner. On the basis of these results, I propose that the ΔcysL mutation causes phosphoadenosine phosphosulfate reductase to consume large amounts of reduced thioredoxin, inducing disulfide stress and activating Spx. The spx mutation restored biofilm formation to the ΔcysL mutant. The ΔcysL mutation reduced expression of the eps operon, which is required for exopolysaccharide production. Moreover, overexpression of the eps operon restored biofilm formation to the ΔcysL mutant. Taken together, these results suggest that the ΔcysL mutation activates Spx, which then inhibits biofilm formation through repression of the eps operon.IMPORTANCEBacillus subtilis has been studied as a model organism for biofilm formation. In this study, I explored why the cysL deletion mutant was defective in biofilm formation. I demonstrated that the ΔcysL mutation activated the disulfide stress response regulator Spx, which inhibits biofilm formation by repressing biofilm matrix genes. Homologs of Spx are highly conserved among Gram-positive bacteria with low G+C contents. In some pathogens, Spx is also reported to inhibit biofilm formation by repressing biofilm matrix genes, even though these genes and their regulation are quite different from those of B. subtilis Thus, the negative regulation of biofilm formation by Spx is likely to be well conserved across species and may be an appropriate target for control of biofilm formation.}, } @article {pmid30718177, year = {2019}, author = {Mathieu, L and Keraval, A and Declercq, NF and Block, JC}, title = {Assessment of a low-frequency ultrasound device on prevention of biofilm formation and carbonate deposition in drinking water systems.}, journal = {Ultrasonics sonochemistry}, volume = {52}, number = {}, pages = {41-49}, doi = {10.1016/j.ultsonch.2018.10.029}, pmid = {30718177}, issn = {1873-2828}, mesh = {Biofilms/*growth & development ; Carbonates/*analysis/chemistry ; Drinking Water/*chemistry/*microbiology ; Hot Temperature ; Sonication/*instrumentation ; }, abstract = {A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition of bacterial cells was not prevented by ultrasound wave treatment. However, whatever the tested system, both further calcium carbonate deposition and biofilm growth were markedly inhibited. Biofilms formed in reactors subjected to low-frequency and low-intensity ultrasound waves were weakly attached to the material. Even though the activity of bacteria was affected as shown by their lower cultivability, membrane permeability did not appear compromised. Ultrasound technology sounds very promising in both the mitigation of drinking water biofilm and carbonate accumulation.}, } @article {pmid30717454, year = {2019}, author = {Chatrath, A and Gangwar, R and Kumari, P and Prasad, R}, title = {In Vitro Anti-Biofilm Activities of Citral and Thymol Against Candida Tropicalis.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {5}, number = {1}, pages = {}, pmid = {30717454}, issn = {2309-608X}, abstract = {Candida tropicalis is an emerging non-albicans Candida species which is pathogenic to the immune-compromised humans, especially in tropical countries, including India. The acquired resistance of Candida species towards antifungal therapies is of major concern. Moreover, limited efficacy and dosage constraint of synthetic drugs have indicated the prerequisite of finding new and natural drugs for treatment. In the present study, we have compared the influence of citral and thymol on C. tropicalis and its biofilm along with expression levels of certain antifungal tolerance genes. The antifungal and anti-biofilm activities of the both were studied using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt (XTT) reduction assay, field emission scanning electron microscope (FE-SEM) and confocal laser scanning microscope (CLSM) and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. Citral and thymol have damaged the cells with distorted surface and less viability. Quantitative real-time PCR analysis showed augmented expression of the cell membrane biosynthesis genes including ERG11/CYT450 against citral and the cell wall related tolerance genes involving CNB1 against thymol thus, depicting their differential mode of actions.}, } @article {pmid30717122, year = {2019}, author = {Gabe, V and Kacergius, T and Abu-Lafi, S and Kalesinskas, P and Masalha, M and Falah, M and Abu-Farich, B and Melninkaitis, A and Zeidan, M and Rayan, A}, title = {Inhibitory Effects of Ethyl Gallate on Streptococcus mutans Biofilm Formation by Optical Profilometry and Gene Expression Analysis.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {3}, pages = {}, pmid = {30717122}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects/growth & development ; Carrier Proteins/genetics/metabolism ; Culture Media/chemistry ; Dental Caries/microbiology/prevention & control ; Dose-Response Relationship, Drug ; Gallic Acid/*analogs & derivatives/pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Glass/chemistry ; Glucosyltransferases/genetics/metabolism ; Humans ; Hydrogen-Ion Concentration ; Lectins/genetics/metabolism ; Microbial Sensitivity Tests ; Polystyrenes/chemistry ; Proton-Translocating ATPases/genetics/metabolism ; Streptococcus mutans/*drug effects/genetics/growth & development/metabolism ; }, abstract = {This study aimed to test the effectiveness of ethyl gallate (EG) against S. mutans biofilm formation on solid surfaces (polystyrene, glass) and acidogenicity, and to examine the effect on expression of related genes. The biofilm that is formed by S. mutans bacteria was evaluated using colorimetric assay and optical profilometry, while the pH of the biofilm growth medium was measured with microelectrode. The expression of genes encoding glucan binding protein B (gbpB), glucosyltranferases B, -C, -D (gtfB, -C, -D) and F-ATPase (atpD, atpF) was assessed using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). It was revealed that all of the EG concentrations significantly suppressed S. mutans biofilm build-up on polystyrene and glass surfaces, and inhibited acidogenicity, in a dose-dependent manner, compared to the activity of untreated bacteria (p < 0.05). The highest concentration of EG (3.53 mM) reduced biofilm formation on polystyrene and glass surfaces by 68% and more than 91%, respectively, and prevented a decrease in pH levels by 95%. The RT-qPCR data demonstrate that the biofilm-producing bacteria treated with EG underwent significant gene expression changes involving the gtfC (a 98.6 increase in fold change), gtfB gene (a 47.5 increase in fold change) and the gbpB gene (a 13.8 increase in fold change). However, for the other genes tested (gtfD, atpD and atpF), the EG treatments did not produce significant expression change compared to the control. EG produced significant gene expression change in three genes-gtfC, gtfB, and gbpB; it has the capacity to inhibit S. mutans biofilm formation on solid surfaces (polystyrene, glass), as well as acidogenicity. Therefore, EG might be used as an antibiofilm and/or anticaries agent for oral formulations in order to reduce the prevalence of dental caries.}, } @article {pmid30716574, year = {2019}, author = {Wang, SY and Yang, XY and Meng, HS and Zhang, YC and Li, XY and Xu, J}, title = {Enhanced denitrification by nano ɑ-Fe2O3 induced self-assembled hybrid biofilm on particle electrodes of three-dimensional biofilm electrode reactors.}, journal = {Environment international}, volume = {125}, number = {}, pages = {142-151}, doi = {10.1016/j.envint.2019.01.060}, pmid = {30716574}, issn = {1873-6750}, mesh = {*Biofilms ; *Bioreactors ; Carbon ; *Denitrification ; *Electrodes ; *Metal Nanoparticles ; Nitrates/chemistry ; Nitrogen/chemistry ; Wastewater/*chemistry ; Water Purification/*instrumentation/methods ; }, abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) represent a novel technology for wastewater denitrification. Formation of mature electroactive biofilm on particle electrodes is crucial to realize successful denitrification in 3D-BERs. However, long start-up time and low electroactivity of the biofilm formed on particle electrodes limit the further application of 3D-BERs in wastewater treatment. In this work, self-assembled hybrid biofilms (SAHB) was cultivated on granular activate carbon particle electrodes of the 3D-BER by assembling nano ɑ-Fe2O3 into the biofilm. ɑ-Fe2O3 was selected due to its high affinity to bacterial outer-membrane cytochromes, an important mediator for microbial electron transfer. SAHB formed on particle electrodes were characterized and the denitrification performance of 3D-BERs was also investigated. Results indicate that nano ɑ-Fe2O3 plays positive roles in the start-up of 3D-BER, which captures more microbes into SAHB and constructs thick biofilm on particle electrodes. Special microorganisms with denitrification function related with genera of Hydrogenophaga and Opitutus are distinctively enriched in SAHB. Nano ɑ-Fe2O3 induced SAHB exhibit superior denitrification performance compared to natural biofilm. The average denitrification rate increases from 0.62 mg total nitrogen/L/h for natural biofilm to 1.73 mg total nitrogen/L/h for SAHB, mainly ascribed to accelerated nitrites reduction. Our work provides new technical solution to enhance nitrates removal in 3D-BERs and brings deep insights into application of bio-electrochemical system in wastewater treatment.}, } @article {pmid30714613, year = {2019}, author = {Ghaziasgar, FS and Poursina, F and Hassanzadeh, A}, title = {Virulence factors, biofilm formation and antibiotic resistance pattern in Enterococcus faecalis and Enterococcus faecium isolated from clinical and commensal human samples in Isfahan, Iran.}, journal = {Annali di igiene : medicina preventiva e di comunita}, volume = {31}, number = {2}, pages = {154-164}, doi = {10.7416/ai.2019.2268}, pmid = {30714613}, issn = {1120-9135}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial ; Enterococcus faecalis/*drug effects/isolation & purification ; Enterococcus faecium/*drug effects/isolation & purification ; Gram-Positive Bacterial Infections/*drug therapy/epidemiology/microbiology ; Humans ; Iran ; Virulence Factors ; }, abstract = {BACKGROUND: The aim of this study was to determine and compare antibiotic resistance profile, biofilm formation ability and frequency of agg and ace genes in Enterococcus spp strains isolated from patients and healthy individuals.

METHODS: A total of 90 non-duplicate Enterococcus spp isolates were isolated from patients and healthy individuals. Antibiotic susceptibility pattern was determined by disk diffusion and E-test method. Virulence genes and two species of enterococci were determined by PCR amplification. The capacity of biofilm formation was also evaluated by microtiter plate technique.

RESULTS: E. faecalis was the predominant species among our clinical isolates (80%). The prevalence of agg and ace genes was 37.8% and 73.3% in clinical and 8.9% and 11.1% in "healthy" samples, respectively. The rate of Multiple Drug Resistant strains was 73.3% and 11.1% in clinical and "healthy" isolates, respectively. The ability of biofilm formation was significantly higher in clinical compared to "healthy" isolates (100% vs 75.6%, P < 0.05).

CONCLUSION: The frequency of ace and agg genes, antibiotic resistance and biofilm formation ability were significantly higher in clinical than in "healthy" isolates (P < 0.05). Existence of agg and ace genes, biofilm formation and antibiotic resistance among the healthy enterococci isolates has a special importance since, in case these strains spread through clinical environments or reach water sources, this issue can be considered as a risk factor for health and sanitation of societY.}, } @article {pmid30714611, year = {2019}, author = {Hoveida, L and Halaji, M and Rostami, S and Mobasherizadeh, S}, title = {Biofilm-producing ability of Staphylococcus spp isolated from different foodstuff products.}, journal = {Annali di igiene : medicina preventiva e di comunita}, volume = {31}, number = {2}, pages = {140-147}, doi = {10.7416/ai.2019.226}, pmid = {30714611}, issn = {1120-9135}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Cross-Sectional Studies ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Bacterial ; *Food Microbiology ; Iran ; Staphylococcus/drug effects/*isolation & purification/physiology ; }, abstract = {BACKGROUND: In recent times, microbial-biofilm contamination has attracted considerable attention to the food industry. Pathogenic microorganisms can attach to food surfaces, grow on them, and form biofilm that cause an increase in the food safety risk. The mechanisms of biofilm formation have become an important issue in the food-processing industry, therefore, the aim of this study is to determine the biofilm formation and profiles of genes involved in biofilm production of staphylococci isolated from various foodstuff products.

MATERIAL AND METHODS: This cross-sectional study was conducted at some grocery stores and confectionaries from September 2015 to October 2016 in different areas of Isfahan, Iran. Staphylococcus spp were isolated from different foodstuff samples including sweet pastries, cakes and similar baked goods, dairy products such as cheese and yogurt, meat products such as sausages, and hamburgers. Standard microbiological methods were used for identification of Staphylococcus spp isolates. Antibiotic susceptibility pattern was determined by the disc diffusion method and icaA/icaD genes have been investigated as PCR target because of their role in the expression of intercellular adhesions involved in biofilm formation by S. aureus.

RESULTS: From a total of 194 different foodstuffs samples, 84 Staphylococcus spp were isolated. Out of the 84 Staphylococcus isolates, 95.2% (80/84) were positive to the ability of biofilm formation. Overall, 35.7% (30/84) and 26.2% (22/84) of Staphylococcus spp isolates were positive for icaA and icaD genes, respectively.

CONCLUSION: The results of the present study indicate that the remarkable rate of biofilm formation with the emergence of antibiotic resistance still remains a significant risk for the food safety, especially in foodstuff samples.}, } @article {pmid30713773, year = {2018}, author = {Mathlouthi, A and Pennacchietti, E and De Biase, D}, title = {Effect of Temperature, pH and Plasmids on In Vitro Biofilm Formation in Escherichia coli.}, journal = {Acta naturae}, volume = {10}, number = {4}, pages = {129-132}, pmid = {30713773}, issn = {2075-8251}, abstract = {Acid resistance (AR) in Escherichia coli is an important trait that protects this microorganism from the deleterious effect of low-pH environments. Reports on biofilm formation in E. coli K12 showed that the genes participating in AR were differentially expressed. Herein, we investigated the relationship between AR genes, in particular those coding for specific transcriptional regulators, and their biofilm-forming ability at the phenotypic level. The latter was measured in 96-well plates by staining the bacteria attached to the well, following 24-hour growth under static conditions, with crystal violet. The growth conditions were as follows: Luria Bertani (LB) medium at neutral and acidic pH, at 37°C or 25°C. We observed that the three major transcriptional regulators of the AR genes (gadX, gadE, gadW) only marginally affected biofilm formation in E. coli. However, a striking and novel finding was the different abilities of all the tested E. coli strains to form a biofilm depending on the temperature and pH of the medium: LB, pH 7.4, strongly supported biofilm formation at 25°C, with biofilm being hardly detectable at 37°C. On the contrary, LB, pH 5.5, best supported biofilm formation at 37°C. Moreover, we observed that when E. coli carried a plasmid, the presence of the plasmid itself affected the ability to develop a biofilm, typically by increasing its formation. This phenomenon varies from plasmid to plasmid, depends on growth conditions, and, to the best of our knowledge, remains largely uninvestigated.}, } @article {pmid30713607, year = {2018}, author = {Koohestani, M and Moradi, M and Tajik, H and Badali, A}, title = {Effects of cell-free supernatant of Lactobacillus acidophilus LA5 and Lactobacillus casei 431 against planktonic form and biofilm of Staphylococcus aureus.}, journal = {Veterinary research forum : an international quarterly journal}, volume = {9}, number = {4}, pages = {301-306}, pmid = {30713607}, issn = {2008-8140}, abstract = {This study was carried out to investigate the stability, antibacterial properties and biofilm removal potential of cell-free supernatant (CFS) of Lactobacillus acidophilus LA5 and Lactobacillus casei 431 against Staphylococcus aureus ATCC 25923. Antibacterial activity of both Lactobacillus strains was measured according to the agar spot method. The CFS was prepared by centrifugation of bacterial suspension at 4000 g for 10 min and the antimicrobial activity was measured using agar-well diffusion. The stability of CFSs during storage at 4.00 ± 2.00 [°]C and 25.00 ± 2.00 [°]C for a period of 4 weeks was measured based on the method of broth micro-dilution assay. Moreover, biofilm removal potential of CFS on 2-days-old biofilm of S. aureus developed on polystyrene and glass surfaces was also determined. The efficacy of CFS on bacterial biofilm established on the glass surface was also observed using fluorescence microscope. Results showed that inhibition zones of L. acidophilus (50.26 mm) were greater than L. casei (37.06 mm). The minimum inhibitory concentration of both CFSs remained stable (40 mg mL[-1]) during the storage for 28 days at 4.00 and 25.00 [°]C and storage temperature did not affect the antibacterial effectiveness of CFS. The addition of both CFSs significantly removed biofilm developed on both tested surfaces in a concentration-dependent manner. Biofilm removal property of L. acidophilus CFS was generally better than L. casei CFS which was confirmed by fluorescence microscope. The application of CFS of probiotic strains (i.e. Lactobacillus) as antibacterial and biofilm removal compounds could be very suitable to control the growth of food-borne pathogens.}, } @article {pmid30713186, year = {2018}, author = {Gulia, S and Bhatt, V and Shetty, M and Prasad, KD and Gupta, P}, title = {Effect of Type II Diabetes Mellitus, Candida Albicans and Streptococcus Mutans on the Biofilm Formation on Prosthetic Materials.}, journal = {The journal of contemporary dental practice}, volume = {19}, number = {12}, pages = {1538-1545}, pmid = {30713186}, issn = {1526-3711}, mesh = {Acrylic Resins ; Biofilms/*growth & development ; Candida albicans/*physiology ; Ceramics ; Chromium Alloys ; Dental Casting Investment ; *Dental Materials ; Dental Porcelain ; Dental Prosthesis/*microbiology ; Diabetes Mellitus, Type 2/*microbiology ; Resins, Synthetic ; Saliva/*microbiology ; *Saliva, Artificial ; Streptococcus mutans/*physiology ; Surface Properties ; }, abstract = {AIM: To investigate the biofilm formation on Prosthetic materials as affected by type II diabetes mellitus, Candida albicans and Streptococcus mutans.

MATERIALS AND METHODS: Two types of saliva, natural saliva, and artificial saliva were collected and prepared respectively. The natural saliva was divided into diabetic and non-diabetic saliva. The artificial saliva was further divided into two groups, one inoculated with Streptococcus mutans and the second with Candida albicans. The 150 samples of various prosthetic materials were prepared using nickel-chromium alloy, ceramic, soft liner, tooth molding powder; heat cured the acrylic resin. The samples were then immersed in natural saliva and artificial saliva and studied for biofilm formation.

RESULTS: Diabetic saliva formed more biofilm than non-diabetic saliva. Streptococcus mutans were able to form more biofilm than Candida albicans in artificial saliva on constitutive androstane receptor (hCAR) and spinal length (SL). In Diabetic saliva, there was a significant difference in the biofilm formation seen between MC and NCA (p < 0.05). No biofilm was formed on hCAR in natural saliva (diabetic or non-diabetic). In artificial saliva inoculated with Candida albicans and streptococcus mutans there is a significant difference in the biofilm formation in all the materials except NCA.

CONCLUSION: Diabetic saliva has more potential to form biofilm than non-diabetic saliva. Also, Candida albicans and Streptococcus mutans both can form a biofilm on materials used with the maximum formation on hCAR. Smoother materials formed less biofilm than rougher surfaces like hCAR, PCM, SL.

CLINICAL SIGNIFICANCE: It is desirable for dental restorative materials to have a low susceptibility for accumulation and formation of biofilm as it may lead to pathologies such as dental caries, periodontal disease, peri-implantitis, etc. which are plaque-related. The most commonly used materials in prosthodontics have been used in the study to establish a direct relationship with the formation of biofilm, this, in turn, helps us to take the right call in choosing a material for a patient with an already compromised systemic condition.}, } @article {pmid30712523, year = {2019}, author = {Shah, FA}, title = {Micro-Raman Spectroscopy Reveals the Presence of Octacalcium Phosphate and Whitlockite in Association with Bacteria-Free Zones Within the Mineralized Dental Biofilm.}, journal = {Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada}, volume = {25}, number = {1}, pages = {129-134}, doi = {10.1017/S1431927618015659}, pmid = {30712523}, issn = {1435-8115}, mesh = {Aged ; Apatites ; Bacteria/*metabolism ; *Biofilms/growth & development ; Calcium Phosphates/*analysis ; Crystallization ; Dental Calculus/chemistry ; Dental Implants/microbiology ; Dental Plaque/*chemistry ; Female ; Humans ; Microscopy, Electron, Scanning/methods ; Minerals/*analysis ; Peri-Implantitis/microbiology ; Spectrometry, X-Ray Emission/methods ; Spectrum Analysis, Raman/*methods ; }, abstract = {Through a correlative analytical approach encompassing backscattered electron scanning electron microscopy (BSE-SEM), energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy, the composition of the mineralized biofilm around a dental implant, retrieved due to peri-implantitis, was investigated. The mineralized biofilm contains two morphologically distinct regions: (i) bacteria-containing zones (Bact+), characterized by aggregations of unmineralized and mineralized bacteria, and intermicrobial mineralization, and (ii) bacteria-free zones (Bact-), comprised mainly of randomly oriented mineral platelets. Intramicrobial mineralization, within Bact+, appears as smooth, solid mineral deposits resembling the morphologies of dental plaque bacteria. Bact- is associated with micrometer-sized Mg-rich mineral nodules. The Ca/P ratio of Bact+ is higher than Bact-. The inorganic phase of Bact+ is carbonated apatite (CHAp), while that of Bact- is predominantly octacalcium phosphate (OCP) and whitlockite (WL) inclusions. Compared with native bone, the inorganic phase of Bact+ (i.e., CHAp) exhibits higher mineral crystallinity, lower carbonate content, and lower Ca/P, C/Ca, Mg/Ca, and Mg/P ratios. The various CaPs found within the mineralized dental biofilm (CHAp, OCP, and WL) are related to the local presence/absence of bacteria. In combination with BSE-SEM and EDX, micro-Raman spectroscopy is a valuable analytical tool for nondestructive investigation of mineralized dental biofilm composition and development.}, } @article {pmid30712376, year = {2019}, author = {Li, C and Atlar, M and Haroutunian, M and Norman, R and Anderson, C}, title = {An investigation into the effects of marine biofilm on the roughness and drag characteristics of surfaces coated with different sized cuprous oxide (Cu2O) particles.}, journal = {Biofouling}, volume = {35}, number = {1}, pages = {15-33}, doi = {10.1080/08927014.2018.1559305}, pmid = {30712376}, issn = {1029-2454}, mesh = {*Biofilms ; Copper/*chemistry ; Friction ; Materials Testing ; Microscopy, Electron, Scanning ; Seawater ; *Surface Properties ; }, abstract = {Biofilms typically increase surface roughness and consequently the drag penalties on marine vessels. However, there is a lack of data regarding the time-dependent influence of biofilms on antifouling surface characteristics and frictional drag, especially for surface coatings with different sizes of cuprous oxide (Cu2O). In this study, a series of pressure drop measurements was carried out using flat plates coated with different sizes of Cu2O. The cuprous oxide-containing surfaces were deployed at sea for a period of six months to allow biofilm to develop. Surface microstructure and roughness analyses were carried out every six weeks using scanning electron microscopy and laser roughness surface profilometry. From the data, the added frictional drag caused by biofilm on ships was predicted, based on roughness function using Granville extrapolations. The analyses indicated that biofilms had significant impacts by altering the surface microstructure, resulting in higher frictional drag. However, due to the interaction between the biofilm and the physico-chemical properties of the substratum for panels coated with larger Cu2O, the roughness and drag measurement results were both found to have fluctuating increments.}, } @article {pmid30712264, year = {2019}, author = {Lai, YS and Ontiveros-Valencia, A and Coskun, T and Zhou, C and Rittmann, BE}, title = {Electron-acceptor loadings affect chloroform dechlorination in a hydrogen-based membrane biofilm reactor.}, journal = {Biotechnology and bioengineering}, volume = {116}, number = {6}, pages = {1439-1448}, doi = {10.1002/bit.26945}, pmid = {30712264}, issn = {1097-0290}, mesh = {Bicarbonates/metabolism ; *Biofilms ; Bioreactors/*microbiology ; Chloroflexi/*physiology ; Chloroform/isolation & purification/*metabolism ; Electrons ; Membranes, Artificial ; Nitrates/metabolism ; Sulfates/metabolism ; Water Pollutants, Chemical/isolation & purification/*metabolism ; Water Purification/methods ; }, abstract = {Chloroform (CF) can undergo reductive dechlorination to dichloromethane, chloromethane, and methane. However, competition for hydrogen (H2), the electron-donor substrate, may cause poor dechlorination when multiple electron acceptors are present. Common acceptors in anaerobic environments are nitrate (NO3[-]), sulfate (SO4[2-]), and bicarbonate (HCO3[-]). We evaluated CF dechlorination in the presence of HCO3[-] at 1.56 e[-] Eq/m[2] -day, then NO3[-] at 0.04-0.15 e[-] Eq/m[2] -day, and finally NO3[-] (0.04 e[-] Eq/m[2] -day) along with SO4[2-] at 0.33 e[-] Eq/m[2] -day in an H2 -based membrane biofilm reactor (MBfR). When the biofilm was initiated with CF-dechlorination conditions (no NO3[-] or SO4[2-]), it yielded a CF flux of 0.14 e[-] Eq/m[2] -day and acetate production via homoacetogenesis up to 0.26 e[-] eq/m[2] -day. Subsequent addition of NO3[-] at 0.05 e[-] Eq/m[2] -day maintained full CF dechlorination and homoacetogenesis, but NO3[-] input at 0.15 e[-] Eq/m[2] -day caused CF to remain in the reactor's effluent and led to negligible acetate production. The addition of SO4[2-] did not affect CF reduction, but SO4[2-] reduction significantly altered the microbial community by introducing sulfate-reducing Desulfovibrio and more sulfur-oxidizing Arcobacter. Dechloromonas appeared to carry out CF dechlorination and denitrification, whereas Acetobacterium (homoacetogen) may have been involved with hydrolytic dechlorination. Modifications to the electron acceptors fed to the MBfR caused the microbial community to undergo changes in structure that reflected changes in the removal fluxes.}, } @article {pmid30711652, year = {2019}, author = {Wan, K and Zhang, M and Ye, C and Lin, W and Guo, L and Chen, S and Yu, X}, title = {Organic carbon: An overlooked factor that determines the antibiotic resistome in drinking water sand filter biofilm.}, journal = {Environment international}, volume = {125}, number = {}, pages = {117-124}, doi = {10.1016/j.envint.2019.01.054}, pmid = {30711652}, issn = {1873-6750}, mesh = {Bacteria/drug effects ; *Biofilms ; Carbon/*pharmacology ; Drinking Water/*chemistry ; *Drug Resistance, Bacterial ; Filtration ; *Genes, Bacterial ; RNA, Ribosomal, 16S ; Water Pollutants/*analysis ; *Water Purification ; }, abstract = {Biofilter, an essential water treatment process, is reported to be the harbor of bacterial antibiotic resistance genes (ARGs). Due to the oligotrophic characteristic of source water, filter biofilm is largely influenced by the concentration of organic carbon. The objective of this study was to investigate the effect of organic carbon concentration on shaping bacterial antibiotic resistome in filter biofilm. Our study was based on pilot-scale sand filters, and we investigated the antibiotic resistome using high-throughput qPCR. A total of 180 resistance genes from eight categories of antibiotics were detected in 15 biofilm samples of three sand filters. The results indicated that higher concentration of influent organic carbon led to lower diversity of bacterial community and richness of antibiotic resistance genes (ARGs) in biofilm. We discovered a negative correlation (p ≤ 0.01) between the richness of ARGs and the corresponding TOC level. Moreover, the absolute abundance of ARGs was positively correlated (p ≤ 0.05) with the abundance of 16S rRNA gene and was determined by the organic carbon concentration. Sand filters with gradient influent organic carbon concentration led to the formation of different antibiotic resistomes and canonical correspondence analysis (CCA) indicated that difference in bacterial community composition was likely the main reason behind this difference. We also observed a similar trend in the relative abundance of ARGs, which increased with the depth of sand filters. However, this trend was more pronounced in filters with low organic carbon concentrations. Overall, this study revealed that the organic carbon concentration determined the absolute abundance of ARGs and also shaped the diversity and relative abundance of ARGs in drinking water sand filters. These results may provide new insights into the mechanism of persistent bacterial antibiotic resistance in drinking water treatment.}, } @article {pmid30710814, year = {2019}, author = {Wang, T and Wang, X and Yuan, L and Luo, Z and Kwame Indira, H}, title = {Start-up and operational performance of Anammox process in an anaerobic baffled biofilm reactor (ABBR) at a moderate temperature.}, journal = {Bioresource technology}, volume = {279}, number = {}, pages = {1-9}, doi = {10.1016/j.biortech.2019.01.114}, pmid = {30710814}, issn = {1873-2976}, mesh = {Anaerobiosis ; *Biofilms ; Biomass ; Bioreactors/microbiology ; Nitrogen/chemistry ; Oxidation-Reduction ; Proteobacteria/physiology ; Sewage/microbiology ; Temperature ; }, abstract = {A lab-scale anaerobic baffled biofilm reactor (ABBR) was used as a novel reactor to start up Anammox process at a moderate temperature around 20 °C and an innovative filling module was adopted as support material. Quick start-up of Anammox process from the aerobic activated sludge was achieved after 47 days operation. The max nitrogen loading rate and nitrogen removing rate attained 1.00 kg N m[-3] d[-1] and 0.90 kg N m[-3] d[-1] after 161 days operation. Scanning electron microscope photographs showed that the structure as well as the states of the micro-aggregates (micro-aggregates sticking on a non-woven fiber, entangling non-woven fibers and enwrapped by non-woven fibers) enhanced biomass retention for Anammox bacteria. Microbial community analysis showed that Anammox bacteria were effectively enriched with Candidatus Brocadia, Candidatus Jettenia and Candidatus Kuenenia being the main Anammox species in the mature biofilms. This contributed to the excellent Anammox operation performance at the moderate temperature.}, } @article {pmid30709828, year = {2019}, author = {Allen, R and Rittmann, BE and Curtiss, R}, title = {Axenic Biofilm Formation and Aggregation by Synechocystis sp. Strain PCC 6803 Are Induced by Changes in Nutrient Concentration and Require Cell Surface Structures.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {7}, pages = {}, pmid = {30709828}, issn = {1098-5336}, mesh = {Bacterial Outer Membrane Proteins/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Biofouling ; Biofuels ; Cellulose/metabolism ; Culture Media/*chemistry ; DNA, Bacterial/genetics/isolation & purification ; Escherichia coli/genetics ; Fimbriae, Bacterial/genetics/*metabolism ; Genes, Bacterial/genetics ; Microscopy, Confocal ; *Nutrients ; Photobioreactors ; Photosynthesis ; Synechocystis/genetics/growth & development/*metabolism ; }, abstract = {Phototrophic biofilms are key to nutrient cycling in natural environments and bioremediation technologies, but few studies describe biofilm formation by pure (axenic) cultures of a phototrophic microbe. The cyanobacterium Synechocystis sp. strain PCC 6803 (here Synechocystis) is a model microorganism for the study of oxygenic photosynthesis and biofuel production. We report here that wild-type (WT) Synechocystis caused extensive biofilm formation in a 2,000-liter outdoor nonaxenic photobioreactor under conditions attributed to nutrient limitation. We developed a biofilm assay and found that axenic Synechocystis forms biofilms of cells and extracellular material but only when cells are induced by an environmental signal, such as a reduction in the concentration of growth medium BG11. Mutants lacking cell surface structures, namely type IV pili and the S-layer, do not form biofilms. To further characterize the molecular mechanisms of cell-cell binding by Synechocystis, we also developed a rapid (8-h) axenic aggregation assay. Mutants lacking type IV pili were unable to aggregate, but mutants lacking a homolog to Wza, a protein required for type 1 exopolysaccharide export in Escherichia coli, had a superbinding phenotype. In WT cultures, 1.2× BG11 medium induced aggregation to the same degree as 0.8× BG11 medium. Overall, our data support that Wza-dependent exopolysaccharide is essential to maintain stable, uniform suspensions of WT Synechocystis cells in unmodified growth medium and that this mechanism is counteracted in a pilus-dependent manner under altered BG11 concentrations.IMPORTANCE Microbes can exist as suspensions of individual cells in liquids and also commonly form multicellular communities attached to surfaces. Surface-attached communities, called biofilms, can confer antibiotic resistance to pathogenic bacteria during infections and establish food webs for global nutrient cycling in the environment. Phototrophic biofilm formation is one of the earliest phenotypes visible in the fossil record, dating back over 3 billion years. Despite the importance and ubiquity of phototrophic biofilms, most of what we know about the molecular mechanisms, genetic regulation, and environmental signals of biofilm formation comes from studies of heterotrophic bacteria. We aim to help bridge this knowledge gap by developing new assays for Synechocystis, a phototrophic cyanobacterium used to study oxygenic photosynthesis and biofuel production. With the aid of these new assays, we contribute to the development of Synechocystis as a model organism for the study of axenic phototrophic biofilm formation.}, } @article {pmid30708330, year = {2019}, author = {Zheng, Y and Huang, Y and Xia, A and Qian, F and Wei, C}, title = {A rapid inoculation method for microalgae biofilm cultivation based on microalgae-microalgae co-flocculation and zeta-potential adjustment.}, journal = {Bioresource technology}, volume = {278}, number = {}, pages = {272-278}, doi = {10.1016/j.biortech.2019.01.083}, pmid = {30708330}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Flocculation ; Microalgae/*physiology ; Time Factors ; }, abstract = {Due to the small size, similar density to water, cells inoculating onto the solid carrier is a major challenge for microalgae biofilm cultivation. To reduce biofilm inoculation time, A. falcatus with long stripe were chosen as the bond linking with the main microalgae cells forming microalgae-microalgae co-flocculation by bridging and twining. The optimal matching species were S. obliquus and A. falcatus with the volume ratio of 4-1. By changing the zeta-potential of the microalgae-microalgae co-flocculation to positive and negative through pH regulating, the inoculation time was significantly shorted from 4 h to 1.5 min due to the charge neutralization. Fortunately, the added A. falcatus and pH regulation has no negative effects on biofilm growth. Inversely, the porous microstructure of microalgae-microalgae co-flocculation improve the transfer efficiency of nutrients, resulting a 90.15% increase on biomass productivity (229.15 g m[-2]) comparing to pure microalgae species.}, } @article {pmid30708091, year = {2019}, author = {Moradi Eslami, L and Vatanpour, M and Aminzadeh, N and Mehrvarzfar, P and Taheri, S}, title = {The comparison of intracanal medicaments, diode laser and photodynamic therapy on removing the biofilm of Enterococcus faecalis and Candida albicans in the root canal system (ex-vivo study).}, journal = {Photodiagnosis and photodynamic therapy}, volume = {26}, number = {}, pages = {157-161}, doi = {10.1016/j.pdpdt.2019.01.033}, pmid = {30708091}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Calcium Hydroxide/pharmacology ; Candida albicans/*drug effects ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*drug effects ; Humans ; In Vitro Techniques ; *Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/pharmacology ; Root Canal Irrigants/*pharmacology ; Tolonium Chloride/pharmacology ; }, abstract = {BACKGROUND AND AIM: Long term success in endodontic therapy is attributed to removal and debridement of intracanal microorganisms. The aim of this study was to compare the antimicrobial effects of calcium hydroxide (Ca(OH)2), triple antibiotic paste (TAP), photodynamic therapy(PDT), toluidine blue(TOL), light emitting diode (LED) and 940 nm diode laser (DL) on the biofilm of Enterococcus faecalis and Candida albicans in the root canal system of ex-vivo human teeth.

MATERIALS & METHODS: 84 intact, uniradicular, extracted human premolar teeth were prepared and the apical foramina were sealed with glass ionomer. The samples were transformed to microtubes containing sterile BHI and were sterilized. After incubation of E. faecalis and C. albicans into the canals, the samples were kept in an incubator for 8 weeks to form the biofilm. Then the samples were randomly divided into 7 groups of 12, including: control and groups treated with Ca(OH)2,TAP, TOl, LED, PDT, and DL. Then the samples were fixed, gold coated and observed under scanning electron microscope (SEM).

RESULT: Significant reductions in biofilm thickness were noted in TAP,PDT and LED (P < 0.05). The greatest reduction in biofilm thickness was seen in TAP; however, the differences between TAP and PDT and LED were not significant (P > 0.05).

CONCLUSION: Since one of the main purposes in root canal therapy is to eliminate the bacteria, this study showed that the application of TAP, PDT, and LED exposure lead to least biofilm thickness.}, } @article {pmid30707339, year = {2019}, author = {Inácio, CP and de Araújo, PSR and Brayner, FA and Alves, LC and Veras, DL and Neves, RP}, title = {Invasive Candida tropicalis Infection Caused by Catheter Biofilm in a Patient with Tongue Cancer.}, journal = {Mycopathologia}, volume = {184}, number = {2}, pages = {345-346}, doi = {10.1007/s11046-018-0316-z}, pmid = {30707339}, issn = {1573-0832}, support = {140352/2015-5//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Biofilms/growth & development ; Candida tropicalis/*isolation & purification ; Candidiasis, Invasive/*diagnosis/microbiology/*pathology ; Catheter-Related Infections/*diagnosis/microbiology/*pathology ; Catheters/microbiology ; Humans ; Microscopy, Electron, Scanning ; Tongue Neoplasms/*complications ; }, abstract = {Systemic infections due to Candida tropicalis are conditions which can frequently lead to death. The aim of this report is to describe the features of C. tropicalis biofilm in a patient with catheter-associated fungemia.}, } @article {pmid30707032, year = {2019}, author = {Hart, JW and Waigh, TA and Lu, JR and Roberts, IS}, title = {Microrheology and Spatial Heterogeneity of Staphylococcus aureus Biofilms Modulated by Hydrodynamic Shear and Biofilm-Degrading Enzymes.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {35}, number = {9}, pages = {3553-3561}, pmid = {30707032}, issn = {1520-5827}, mesh = {Animals ; Biofilms/*drug effects ; Cattle ; Deoxyribonuclease I/*pharmacology ; Elasticity ; Endopeptidase K/*pharmacology ; Hydrodynamics ; Hypocreales/enzymology ; Rheology/methods ; Staphylococcus aureus/*physiology ; Viscoelastic Substances/chemistry/*metabolism ; Viscosity ; }, abstract = {Particle tracking microrheology was used to investigate the viscoelasticity of Staphylococcus aureus biofilms grown in microfluidic cells at various flow rates and when subjected to biofilm-degrading enzymes. Biofilm viscoelasticity was found to harden as a function of shear rate but soften with increasing height away from the attachment surface in good agreement with previous bulk results. Ripley's K-function was used to quantify the spatial distribution of the bacteria within the biofilm. For all conditions, biofilms would cluster as a function of height during growth. The effects of proteinase K and DNase-1 on the viscoelasticity of biofilms were also investigated. Proteinase K caused an order of magnitude change in the compliances, softening the biofilms. However, DNase-1 was found to have no significant effects over the first 6 h of development, indicating that DNA is less important in biofilm maintenance during the initial stages of growth. Our results demonstrate that during the preliminary stages of Staphylococcus aureus biofilm development, column-like structures with a vertical gradient of viscoelasticity are established and modulated by the hydrodynamic shear caused by fluid flow in the surrounding environment. An understanding of these mechanical properties will provide more accurate insights for removal strategies of early-stage biofilms.}, } @article {pmid30706947, year = {2019}, author = {Flynn, PB and Graham, WG and Gilmore, BF}, title = {Acinetobacter baumannii biofilm biomass mediates tolerance to cold plasma.}, journal = {Letters in applied microbiology}, volume = {68}, number = {4}, pages = {344-349}, pmid = {30706947}, issn = {1472-765X}, support = {BB/P008496/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Acinetobacter Infections ; Acinetobacter baumannii/*growth & development/*metabolism ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Biomass ; Drug Resistance, Multiple, Bacterial/physiology ; Humans ; Microscopy, Electron, Scanning ; Plankton ; Plasma Gases/*pharmacology ; }, abstract = {Acinetobacter baumannii is an intrinsically multidrug-resistant pathogen that, when existing as a biofilm, confers increased environmental tolerance to desiccation, nutrient starvation as well as increased tolerance to antimicrobials. Outbreaks of A. baumannii infections within the clinical setting are often associated with the biofilm phenotype. This study investigates the role of biofilm biomass in A. baumannii susceptibility to exposure to a kilohertz-driven, in-house-designed, cold plasma jet, through the examination of cold plasma treatment efficacy in A. baumannii biofilms grown over various times for up to 72 h. For biofilms grown for 24, 48 and 72 h, D values were 19·32 ± 2·71, 29·18 ± 3·15 and 24·70 ± 3·07 s respectively. Monitoring A. baumannii biofilm biomass over these time periods revealed that the greatest biomass was observed at 48 h with the lowest biofilm biomass at 24 h growth. Enumeration of viable biofilm colony counts at each time point was comparable. Scanning electron microscopy images of plasma-treated biofilms revealed extensive surface damage of A. baumannii cells. These results describe the role of biomass in mediating A. baumannii biofilm susceptibility to cold plasma treatment, implicating the biofilm matrix as a protective barrier to the antimicrobial effects of cold plasma. SIGNIFICANCE AND IMPACT OF THE STUDY: Acinetobacter baumannii biofilm formation results in increased environmental and antimicrobial tolerance and resistance compared to the planktonic phenotype. Cold plasma technology is increasingly investigated as a new tool for decontamination of biofilm-contaminated surfaces, especially those found in the clinical setting. This new technology presents a promising approach to the remediation of surfaces contaminated by biofilms. This study identifies the role played by A. baumannii biofilm biomass in mediating tolerance and susceptibility to cold plasma treatment. This work demonstrates that increased biofilm biomass reduces the efficacy of antimicrobial species generated by cold plasma, resulting in greater tolerance to plasma exposure.}, } @article {pmid30706343, year = {2019}, author = {Martínez-García, S and Ortiz-García, CI and Cruz-Aguilar, M and Zenteno, JC and Murrieta-Coxca, JM and Pérez-Tapia, SM and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {Competition/antagonism associations of biofilm formation among Staphylococcus epidermidis Agr groups I, II, and III.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {2}, pages = {143-153}, pmid = {30706343}, issn = {1976-3794}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Catheter-Related Infections/microbiology ; DNA, Bacterial/genetics ; Disease Models, Animal ; Female ; Gene Expression Regulation, Bacterial/*genetics ; Genes, Bacterial/*genetics ; Genotype ; Humans ; Mice ; Mice, Inbred BALB C ; Multilocus Sequence Typing ; Operon ; Quorum Sensing ; Skin/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*genetics/growth & development/isolation & purification/*physiology ; Trans-Activators/*classification/*genetics ; }, abstract = {Staphylococci have quorum-sensing (QS) systems that enable cell-to-cell communication, as well as the regulation of numerous colonization and virulence factors. The accessory gene regulator (Agr) operon is one of the Staphylococcus genus QS systems. Three groups (I, II, and III) are present in Staphylococcus epidermidis Agr operon. To date, it is unknown whether Agr groups can interact symbiotically during biofilm development. This study analyzed a symbiotic association among Agr groups during biofilm formation in clinical and commensal isolates. Different combinations among Agr group isolates was used to study biofilm formation in vitro and in vivo (using a mouse catheter-infection model). The analysis of Agr groups were also performed from samples of human skin (head, armpits, and nostrils). Different predominant coexistence was found within biofilms, suggesting symbiosis type. In vitro, Agr I had a competition with Agr II and Agr III. Agr II had a competition with Agr III, and Agr II was an antagonist to Agr I and III when the three strains were combined. In vivo, Agr II had a competition to Agr I, but Agr I and II were antagonists to Agr III. The associations found in vitro and in vivo were also found in different sites of the skin. Besides, other associations were observed: Agr III antagonized Agr I and II, and Agr III competed with Agr I and Agr II. These results suggest that, in S. epidermidis, a symbiotic association of competition and antagonism occurs among different Agr groups during biofilm formation.}, } @article {pmid30706301, year = {2019}, author = {Bino, E and Lauková, A and Ščerbová, J and Kubašová, I and Kandričáková, A and Strompfová, V and Miltko, R and Belzecki, G}, title = {Fecal coagulase-negative staphylococci from horses, their species variability, and biofilm formation.}, journal = {Folia microbiologica}, volume = {64}, number = {6}, pages = {719-726}, pmid = {30706301}, issn = {1874-9356}, support = {2/0006/17//VEGA, Slovakia/ ; 2/0012/16//VEGA Slovakia/ ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/growth & development ; Coagulase/*deficiency ; Feces/*microbiology ; Gastrointestinal Microbiome ; Horses ; Lactic Acid/metabolism ; Methicillin Resistance ; Microbial Sensitivity Tests ; Poland/epidemiology ; Slovakia/epidemiology ; Species Specificity ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus/classification/drug effects/*isolation & purification/physiology ; }, abstract = {The intestinal microbiota has enormous impact on the health and performance of horses. Staphylococci belong in the phylum Firmicutes, and their occurrence, especially of methicillin-resistant strains and species, has been reported in horses previously. Moreover, biofilm formation is one of the virulence factors; it has been not completely studied in fecal coagulase-negative staphylococci (CoNS) from horses. Therefore, this study was focused on biofilm formation by various species of fecal CoNS from horses because it has been never reported before. In addition, their antibiotic profile was tested. Horses (42) of various breeds from Slovakia/Poland were sampled. Variability in the species of CoNS was detected in feces of horses. Thirty-two strains were identified by using the MALDI-TOF system and classified into nine species and three subspecies of CoNS: Staphylococcus capitis, S. cohnii subsp. cohnii, S. cohnii subsp. urealyticus, S. cohnii subsp. casei, S. epidermidis, S. haemolyticus, S. pasteuri, S. sciuri, S. vitulinus, S. warneri, and S. xylosus. The most frequent species was S. vitulinus. Twenty-two strains showed high biofilm production; 10 strains showed low-grade biofilm production. The highest biofilm formation was measured in the species S. xylosus. Eleven strains (of 32) were methicillin-resistant; the others were susceptible to methicillin.}, } @article {pmid30704099, year = {2019}, author = {Cadavid, E and Echeverri, F}, title = {The Search for Natural Inhibitors of Biofilm Formation and the Activity of the Autoinductor C6-AHL in Klebsiella pneumoniae ATCC 13884.}, journal = {Biomolecules}, volume = {9}, number = {2}, pages = {}, pmid = {30704099}, issn = {2218-273X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Benzofurans/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Biological Products/chemistry/*pharmacology ; Cell Survival/drug effects ; Coumaric Acids/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Klebsiella pneumoniae/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {Human nosocomial infections are common around the world. One of the main causes is the bacteria Klebsiella pneumoniae, which shows high rates of resistance to antibiotics. Thus, drugs with novel mechanisms of action are needed. In this work, we report the effects of various natural substances on the formation of biofilm in Klebsiella pneumoniae, as well as its stability. The effect of the molecules on the growth of K. pneumoniae was initially determined by measuring the optical density. The modification of the biofilm, the changes relating to its resistance, the effects on the bacterial adhesion to the urethral catheter and its antagonist role the hexanoyl-homoserinelactone were assessed by crystal violet, as well as by microscopy. The best effects were obtained with 3-methyl-2(5H)-furanone and 2´-hydroxycinnamic acid, which inhibited the formation of biofilm by 67.38% and 65.06%, respectively. Additionally, the remaining biofilm formed was more susceptible to gentamicin. Through microscopy examination, there were evident changes in the biofilm and adherence on the polyvinyl chloride (PVC) urethral catheter. Besides, 3-methyl-2(5H)-furanone inhibited the biofilm-forming effect of the autoinducer hexanoyl-homoserinelactone. Thus, these molecules could be developed as supplemental of antibiotics.}, } @article {pmid30704020, year = {2019}, author = {Benzaid, C and Belmadani, A and Djeribi, R and Rouabhia, M}, title = {The Effects of Mentha × piperita Essential Oil on C. albicans Growth, Transition, Biofilm Formation, and the Expression of Secreted Aspartyl Proteinases Genes.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {8}, number = {1}, pages = {}, pmid = {30704020}, issn = {2079-6382}, abstract = {The rise in resistance and changes in the spectrum of Candida infections have generated enormous interest in developing new antifungal drugs using natural molecules such as plant essential oils (EOs). Antimicrobial activity against foodborne pathogenic and spoilage microorganisms has been reported for EOs. The goal of this study was to assess the effect of Mentha × piperita essential oil (EO) on C. albicans growth, transition (change from blastospore to hyphae forms), and biofilm formation as well as on the expression of certain virulent genes. We show that whole EO and its vapor attenuated the yeast's growth, compared to that in the control. The effect of the EO was comparable to that of amphotericin-B (AmB). The EO and its vapor significantly decreased the morphological changes of C. albicans, reduced biofilm formation, and disrupted mature C. albicans biofilms. The effect produced by whole EO on biofilm formation/disruption was notably comparable to that observed with AmB. Exposure of C. albicans to EO and its vapor downregulated the expression of various genes, such as secreted aspartyl proteinases (SAP 1, 2, 3, 9, 10) and hyphal wall protein 1 (HWP1). Altogether, these results provide new insight into the efficacy of Mentha × piperita EO against C. albicans and suggest the potential of Mentha × piperita EO for use as an antifungal therapy in multiple applications.}, } @article {pmid30703118, year = {2019}, author = {Dangel, ML and Dettmann, JC and Haßelbarth, S and Krogull, M and Schakat, M and Kreikemeyer, B and Fiedler, T}, title = {The 5'-nucleotidase S5nA is dispensable for evasion of phagocytosis and biofilm formation in Streptococcus pyogenes.}, journal = {PloS one}, volume = {14}, number = {1}, pages = {e0211074}, pmid = {30703118}, issn = {1932-6203}, mesh = {*5'-Nucleotidase/immunology/metabolism ; Animals ; *Bacterial Proteins/immunology/metabolism ; Biofilms/*growth & development ; Humans ; *Immune Evasion ; Larva/immunology/metabolism/microbiology ; Moths/immunology/metabolism/microbiology ; *Neutrophils/immunology/metabolism/microbiology ; *Phagocytosis ; Streptococcus pyogenes/pathogenicity/*physiology ; }, abstract = {5'-nucleotidases are widespread among all domains of life. The enzymes hydrolyze phosphate residues from nucleotides and nucleotide derivatives. In some pathobiontic bacteria, 5'-nucleotidases contribute to immune evasion by dephosphorylating adenosine mono-, di-, or tri-phosphates, thereby either decreasing the concentration of pro-inflammatory ATP or increasing the concentration of anti-inflammatory adenosine, both acting on purinergic receptors of phagocytic cells. The strict human pathogen Streptococcus pyogenes expresses a surface-associated 5'-nucleotidase (S5nA) under infection conditions that has previously been discussed as a potential virulence factor. Here we show that deletion of the S5nA gene does not significantly affect growth in human blood, evasion of phagocytosis by neutrophils, formation of biofilms and virulence in an infection model with larvae of the greater wax moth Galleria mellonella in S. pyogenes serotypes M6, M18 and M49. Hence, the surface-associated 5'-nucleotidase S5nA seems dispensable for evasion of phagocytosis and biofilm formation in S. pyogenes.}, } @article {pmid30702944, year = {2019}, author = {Aly, MA and Reimhult, E and Kneifel, W and Domig, KJ}, title = {Characterization of Biofilm Formation by Cronobacter spp. Isolates of Different Food Origin under Model Conditions.}, journal = {Journal of food protection}, volume = {82}, number = {1}, pages = {65-77}, doi = {10.4315/0362-028X.JFP-18-036}, pmid = {30702944}, issn = {1944-9097}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; *Cronobacter/enzymology/genetics/physiology ; *Cronobacter sakazakii ; Dairy Products ; Food Microbiology ; Glucosyltransferases/*genetics/metabolism ; Humans ; Infant ; Infant, Newborn ; Polymerase Chain Reaction ; }, abstract = {Cronobacter spp. are opportunistic human pathogens that cause serious diseases in neonates and immunocompromised people. Owing to their biofilm formation on various surfaces, both their detection and their removal from production plants constitute a major challenge. In this study, food samples were randomly collected in Austria and examined for the presence of Cronobacter spp. Presumptive isolates were identified by a polyphasic approach. Five percent of the samples were positive for C. sakazakii and 2.4% for C. dublinensis. Individual growth of the isolates was characterized based on lag time, growth rate, and generation time. During an incubation period of 6 to 72 h, biofilm formation of 11 selected isolates was quantified under model conditions by a crystal violet staining assay with 96-well plates with different carbon sources (lactose, glucose, maltose, sucrose, and sodium acetate) and NaCl levels and under variable temperature and pH conditions. Biofilm formation was more pronounced at lactose concentrations between 0.25 and 3% compared with 5% lactose, which lead to thinner layers. C. sakazakii isolate C7, isolated from infant milk powder, was the strongest biofilm producer at 10 mM Mg[2+] and 5 mM Mn[2+], 0.5% sodium acetate, at pH levels between 7 and 9 at 37°C for 24 h. C. sakazakii strain C6 isolated from a plant air filter was identified as a moderate biofilm former and C. sakazakii strain DSM 4485, a clinical isolate, as a weak biofilm former. Based on PCR detection, genes bcsA, bcsB, and bcsG encoding for cellulose could be identified as markers for biofilm formation. Isolates carrying bcsA and bcsB showed significantly stronger biofilm formation than isolates without these genes (P < 0.05), in strong correlation with the results obtained in the crystal violet assay. Further investigations using confocal laser scanning microscopy revealed that extracellular polymeric substances and glycocalyx secretions were the dominating components of the biofilms and that the viable fraction of bacteria in the biofilm decreased over time.}, } @article {pmid30702383, year = {2019}, author = {Fernandez-Moure, JS and Mydlowska, A and Shin, C and Vella, M and Kaplan, LJ}, title = {Nanometric Considerations in Biofilm Formation.}, journal = {Surgical infections}, volume = {20}, number = {3}, pages = {167-173}, doi = {10.1089/sur.2018.237}, pmid = {30702383}, issn = {1557-8674}, mesh = {Bacteria/*growth & development ; Biofilms/*growth & development ; *Chemical Phenomena ; Humans ; Nanomedicine/*methods ; Prostheses and Implants/*microbiology ; *Surface Properties ; }, abstract = {Prosthetic contamination and biofilm formation continue to plague implanted materials. With increasing resistance to traditional antibiotic regimens, alternative approaches to preventing bacterial adhesion and biofilm formation have focused on the physiochemical properties of the prosthetics. Roughness, topography, hydrophobicity, porosity, charge, stiffness, and surface area all influence the processes of adhesion and colonization leading to biofilm formation. In this review, we discuss the physiochemical properties of solid and porous prosthetic materials that influence biofilm formation at the nanometric scale.}, } @article {pmid30700643, year = {2019}, author = {Kokubu, E and Kinoshita, E and Ishihara, K}, title = {Inhibitory Effects of Lingonberry Extract on Oral Streptococcal Biofilm Formation and Bioactivity.}, journal = {The Bulletin of Tokyo Dental College}, volume = {60}, number = {1}, pages = {1-9}, doi = {10.2209/tdcpublication.2018-0007}, pmid = {30700643}, issn = {0040-8891}, mesh = {Biofilms/*drug effects ; Fruit/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Streptococcus/*drug effects ; Streptococcus mutans/drug effects ; Streptococcus sanguis/drug effects ; Streptococcus sobrinus/drug effects ; Vaccinium macrocarpon/chemistry ; Vaccinium vitis-idaea/*chemistry ; }, abstract = {Phenolic compounds in fruits such as cranberries have been shown to promote a number of biological activities. The purpose of this study was to investigate the effects of polyphenolic compound-containing lingonberry extract on oral streptococci and compare them with the known anti-cariogenic activity of cranberries. Water-soluble and polyphenol-rich fractions (Fractions I and II, respectively) were isolated from cranberries and lingonberries. The effects of those fractions on the biofilm formation ability and bioactivity of Streptococcus mutans MT8148R, Streptococcus sobrinus 6715, and Streptococcus sanguinis ATCC 10556 were then evaluated. Cranberry or lingonberry Fraction II (at 0.5-1 mg/ml) significantly reduced biofilm formation by S. mutans, S. sobrinus, and S. sanguinis. In contrast, cranberry or lingonberry Fraction I (at 0.5-2 mg/ml) increased biofilm formation by S. mutans and S. sobrinus, but not by S. sanguinis. Fractions I and II (at 1-2 mg/ml) also reduced the bioactivity of S. mutans, while Fraction II (at 0.5 mg/ml) enhanced the bioactivity of all tested strains. The results revealed that lingonberries contained a larger amount of polyphenol than cranberries and that they showed almost the same level of activity against the biofilm formation ability and bioactivity of oral streptococci. This indicates that polyphenol-rich lingonberry fraction offers a promising natural food derivative for prevention of dental caries.}, } @article {pmid30698495, year = {2019}, author = {Woźniak-Biel, A and Bugla-Płoskońska, G and Burdzy, J and Korzekwa, K and Ploch, S and Wieliczko, A}, title = {Antimicrobial Resistance and Biofilm Formation in Enterococcus spp. Isolated from Humans and Turkeys in Poland.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {2}, pages = {277-286}, pmid = {30698495}, issn = {1931-8448}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial/*genetics ; Enterococcus/*drug effects/*genetics ; Enterococcus faecalis/drug effects/genetics ; Enterococcus faecium/drug effects ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; Poland/epidemiology ; Turkeys/*microbiology ; }, abstract = {Enterococci are a natural component of the intestinal flora of many organisms, including humans and birds. As opportunistic pathogens, they can cause fatal infections of the urinary tract and endocarditis in humans, whereas in poultry symptoms are joint disease, sepsis, and falls in the first week of life. The study covered 107 Enterococcus strains-56 isolated from humans and 51 from turkeys. Among the isolates investigated Enterococcus faecalis was detected in 80.36% of human and 80.39% of turkey samples. Enterococcus faecium was identified in 8.93% of human and 17.65% of turkey strains. The highest percentage of the strains was resistant to tetracycline as follows: 48 (85.71%) and 48 (94.12%) of human and turkey strains, respectively. Resistance to erythromycin occurred in 37.50% of the human and in 76.47% of turkey strains, otherwise 27.10% of all strains showed resistance to ciprofloxacin. Our study revealed that 25% of human and 15.69% of turkey strains were resistant to vancomycin. Multidrug resistance showed in 32.14% and 43.14% of human and turkey strains, respectively. The tetracycline resistance gene, tetM, was detected in 82.24% of all strains analyzed, whereas the tetO gene was found in 53.57% of human but only in 7.84% of turkey strains. The vancomycin resistance gene (vanA) was detected in seven Enterococcus strains (six isolated from turkeys and one from humans). The ermB gene (resistance to macrolide) was detected in 55.14% of all isolates (42.86% of human and 68.63% of turkey strains), whereas the ermA gene was detected in 17.65% of turkey but only in 3.57% of human isolates. All the strains had the ability to form biofilms. A stronger biofilm was formed after 24-hour incubation by strains isolated from turkeys, whereas after 48 hours of incubation all examined strains produced strong biofilm.}, } @article {pmid30698031, year = {2018}, author = {Ricciardelli, A and Casillo, A and Papa, R and Monti, DM and Imbimbo, P and Vrenna, G and Artini, M and Selan, L and Corsaro, MM and Tutino, ML and Parrilli, E}, title = {Pentadecanal inspired molecules as new anti-biofilm agents against Staphylococcus epidermidis.}, journal = {Biofouling}, volume = {34}, number = {10}, pages = {1110-1120}, doi = {10.1080/08927014.2018.1544246}, pmid = {30698031}, issn = {1029-2454}, mesh = {Aldehydes/chemical synthesis/chemistry/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Disinfectants/chemical synthesis/chemistry/*pharmacology ; Drug Synergism ; Humans ; Microbial Sensitivity Tests ; Staphylococcus epidermidis/*drug effects/growth & development ; Vancomycin/*pharmacology ; }, abstract = {Staphylococcus epidermidis, a harmless human skin colonizer, is a significant nosocomial pathogen in predisposed hosts because of its capability to form a biofilm on indwelling medical devices. In a recent paper, the purification and identification of the pentadecanal produced by the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, able to impair S. epidermidis biofilm formation, were reported. Here the authors report on the chemical synthesis of pentadecanal derivatives, their anti-biofilm activity on S. epidermidis, and their action in combination with antibiotics. The results clearly indicate that the pentadecanal derivatives were able to prevent, to a different extent, biofilm formation and that pentadecanoic acid positively modulated the antimicrobial activity of the vancomycin. The cytotoxicity of these new anti-biofilm molecules was tested on two different immortalized eukaryotic cell lines in view of their potential applications.}, } @article {pmid30698028, year = {2018}, author = {Jahid, IK and Mizan, MFR and Myoung, J and Ha, SD}, title = {Aeromonas hydrophila biofilm, exoprotease, and quorum sensing responses to co-cultivation with diverse foodborne pathogens and food spoilage bacteria on crab surfaces.}, journal = {Biofouling}, volume = {34}, number = {10}, pages = {1079-1092}, doi = {10.1080/08927014.2018.1519069}, pmid = {30698028}, issn = {1029-2454}, mesh = {Acyl-Butyrolactones/metabolism ; Aeromonas hydrophila/enzymology/*growth & development/physiology ; Animals ; Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Brachyura/*microbiology ; Coculture Techniques ; Exopeptidases/*metabolism ; Microbiota/*physiology ; Quorum Sensing/*physiology ; Seafood/*microbiology ; }, abstract = {The effects of dual species interactions on biofilm formation by Aeromonas hydrophila in the presence of Pseudomonas aeruginosa, Pseudomonas fluorescens, Pectobacterium carotovorum, Salmonella Typhimurium, and Listeria monocytogenes were examined. High-performance liquid chromatography and liquid-chromatography-mass spectrometry were performed to identify N-acyl homoserine lactone (AHL) molecules secreted by monocultures and dual cultures grown in crab broth. Field emission scanning electron microscopy was performed to observe attachment and biofilm formation. P. aeruginosa and P. fluorescens inhibited biofilm formation by A. hydrophila on the crab surface, without affecting their own biofilm-forming abilities. Dual biofilms of S. Typhimurium, L. monocytogenes, or P. carotovorum did not affect A. hydrophila biofilm formation. Exoprotease, AHL, and AI-2 levels were significantly reduced in dual cultures of P. aeruginosa and P. fluorescens with A. hydrophila, supporting the relationship between quorum sensing and biofilm formation. Dual-species biofilms were studied in their natural environment and in the laboratory.}, } @article {pmid30697382, year = {2018}, author = {Froughreyhani, M and Salemmilani, A and Mozafari, A and Hosein-Soroush, M}, title = {Effect of electric currents on antibacterial effect of chlorhexidine against Entrococcus faecalis biofilm: An in vitro study.}, journal = {Journal of clinical and experimental dentistry}, volume = {10}, number = {12}, pages = {e1223-e1229}, pmid = {30697382}, issn = {1989-5488}, abstract = {BACKGROUND: This in vitro study was mainly aimed to evaluate the effect of high-frequency alternating currents (AC) applied by an electronic apex locator (EAL) on the antibacterial properties of chlorhexidine (CHX) on E. faecalis biofilm.

MATERIAL AND METHODS: The root canals of 120 extracted human single-rooted teeth were prepared using Gates-Glidden drills and hand K-files. After contaminating the root canals with E. faecalis, they were incubated for 60 days. Then, the teeth were randomly divided into six experimental groups (n=20). Group 1, 2% CHX; group 2, normal saline (NS) with direct current (DC); group 3, normal saline (NS) with high-frequency alternating current (AC); group 4, 2% CHX with DC; group 5, 2% CHX with AC; group 6, control (normal saline). The samples were collected from the root canal walls of 16 teeth in each group and 1:10 serial dilutions were prepared and added to Muller-Hinton agar (MHA) plates and incubated at 37°C for 48 h. The longitudinal sections of the other 4 teeth used to observe under a scanning electron microscope (SEM). A classic colony counting technique was used for counting the vital E. faecalis bacteria in MHA. Two-way ANOVA was used for statistical analysis of the data. The level of significance was set at P<0.05.

RESULTS: The electric current significantly changed the colony-forming units (CFU) values (P<0.001). According to pair-wise comparisons, the highest CFU difference was observed between the AC group and the group without electric current (P<0.001); furthermore, the difference between the DC group and the group without electric current was not significant (P=0.823).

CONCLUSIONS: The highest bioelectric effect occurred with the use of high-frequency alternating electric current in the form of an apex locator with CHX as a canal irrigant. Key words:Biofilm, Chlorhexidine, Direct current, Electric current, Enterococcus faecalis.}, } @article {pmid30694560, year = {2019}, author = {Torabi Delshad, S and Soltanian, S and Sharifiyazdi, H and Bossier, P}, title = {Effect of catecholamine stress hormones (dopamine and norepinephrine) on growth, swimming motility, biofilm formation and virulence factors of Yersinia ruckeri in vitro and an in vivo evaluation in rainbow trout.}, journal = {Journal of fish diseases}, volume = {42}, number = {4}, pages = {477-487}, doi = {10.1111/jfd.12934}, pmid = {30694560}, issn = {1365-2761}, mesh = {Animals ; Biofilms/*drug effects ; Catecholamines/*pharmacology ; Dopamine/pharmacology ; Fish Diseases/microbiology/prevention & control ; Locomotion/drug effects ; Norepinephrine/pharmacology ; Oncorhynchus mykiss/*microbiology ; Virulence ; Virulence Factors/metabolism ; Yersinia ruckeri/*drug effects/physiology ; }, abstract = {In this study, we evaluated the impact of the catecholamines on growth, swimming motility, biofilm formation and some virulence factors activities of pathogenic Yersinia ruckeri. Norepinephrine and dopamine (at 100 µM) significantly increased the growth of Y. ruckeri in culture media containing serum. An increase in swimming motility of the pathogen was found following the exposure to the hormones; however, no effect was seen on caseinase, phospholipase and haemolysin productions. Further, antagonists for the catecholamine receptors were observed to block some of the influences of the catecholamines. Indeed, the effects of catecholamines were inhibited by chlorpromazine (the dopaminergic receptor antagonist) for dopamine, labetalol (α-and β-adrenergic receptor antagonist) and phenoxybenzamine (the α-adrenergic receptor antagonist) for norepinephrine, but propranolol (the β-adrenergic receptor antagonist) showed no effect. Pretreatment of Y. ruckeri with the catecholamines resulted in a significant enhancement of its virulence towards rainbow trout and the antagonists could neutralize the effect of the stress hormones in vivo. In summary, our results show that the catecholamines increase the virulence of Y. ruckeri which is pathogenic to trout through increasing the motility, biofilm formation and growth.}, } @article {pmid30692967, year = {2018}, author = {Li, Z and Xiang, Z and Zeng, J and Li, Y and Li, J}, title = {A GntR Family Transcription Factor in Streptococcus mutans Regulates Biofilm Formation and Expression of Multiple Sugar Transporter Genes.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3224}, pmid = {30692967}, issn = {1664-302X}, abstract = {GntR family transcription factors have been implicated in the regulation of carbohydrate transport and metabolism in many bacteria. However, the function of this transcription factor family is poorly studied in Streptococcus mutans, which is a commensal bacterium in the human oral cavity and a well-known cariogenic pathogen. One of the most important virulence traits of S. mutans is its ability to transport and metabolize carbohydrates. In this study, we identified a GntR transcription factor in S. mutans named StsR (Sugar Transporter Systems Regulator). The deletion of the stsR gene in S. mutans caused a decrease in both the formation of biofilm and the production of extracellular polysaccharides (EPS) at early stage. Global gene expression profiling revealed that the expression levels of 188 genes were changed in the stsR mutant, which could be clustered with the sugar PTS and ABC transporters. Furthermore, StsR protein was purified and its conserved DNA binding motif was determined using electrophoretic mobility shift assays (EMSA) and DNase I footprinting assays. Collectively, the results of this research indicate that StsR is an important transcription factor in S. mutans that regulates the expression of sugar transporter genes, production of EPS and formation of biofilm.}, } @article {pmid30692576, year = {2019}, author = {Jing, X and Huang, X and Haapasalo, M and Shen, Y and Wang, Q}, title = {Modeling Oral Multispecies Biofilm Recovery After Antibacterial Treatment.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {804}, pmid = {30692576}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Chlorhexidine/analogs & derivatives/pharmacology ; Humans ; Iodine Compounds/pharmacology ; Models, Theoretical ; Mouth/*microbiology ; Quorum Sensing/drug effects ; Sodium Hypochlorite/pharmacology ; }, abstract = {Recovery of multispecies oral biofilms is investigated following treatment by chlorhexidine gluconate (CHX), iodine-potassium iodide (IPI) and Sodium hypochlorite (NaOCl) both experimentally and theoretically. Experimentally, biofilms taken from two donors were exposed to the three antibacterial solutions (irrigants), respectively, for 10 minutes. We observe that (a) live bacterial cell ratios decline for a week after the exposure and the trend then reverses beyond the week; after fifteen weeks, live bacterial cell ratios in biofilms fully return to their pretreatment levels; (b) NaOCl is shown as the strongest antibacterial agent for the oral biofilms; (c) multispecies oral biofilms from different donors showed no difference in their susceptibility to all the bacterial solutions. Guided by the experiment, a mathematical model for biofilm dynamics is developed, accounting for multiple bacterial phenotypes, quorum sensing, and growth factor proteins, to describe the nonlinear time evolutionary behavior of the biofilms. The model captures time evolutionary dynamics of biofilms before and after antibacterial treatment very well. It reveals the important role played by quorum sensing molecules and growth factors in biofilm recovery and verifies that the source of biofilms has a minimal effect to their recovery. The model is also applied to describe the state of biofilms of various ages treated respectively by CHX, IPI and NaOCl, taken from different donors. Good agreement with experimental data predicted by the model is obtained as well, confirming its applicability to modeling biofilm dynamics in general.}, } @article {pmid30692179, year = {2019}, author = {Alboslemy, T and Yu, B and Rogers, T and Kim, MH}, title = {Staphylococcus aureus Biofilm-Conditioned Medium Impairs Macrophage-Mediated Antibiofilm Immune Response by Upregulating KLF2 Expression.}, journal = {Infection and immunity}, volume = {87}, number = {4}, pages = {}, pmid = {30692179}, issn = {1098-5522}, support = {R01 NR015674/NR/NINR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Culture Media, Conditioned/*chemistry ; Host-Pathogen Interactions ; Humans ; Immunity, Innate ; Kruppel-Like Transcription Factors/genetics/*immunology ; Macrophages/*immunology/microbiology ; Mice ; NF-kappa B/genetics/immunology ; RAW 264.7 Cells ; Staphylococcal Infections/genetics/*immunology/microbiology ; Staphylococcus aureus/chemistry/genetics/*physiology ; }, abstract = {Staphylococcus aureus infections associated with the formation of biofilms on medical implants or host tissue play a critical role in the persistence of chronic infections. One critical mechanism of biofilm infection that leads to persistent infection lies in the capacity of biofilms to evade the macrophage-mediated innate immune response. It is now increasingly apparent that microorganisms exploit the negative regulatory mechanisms of the pattern recognition receptor (PRR)-mediated inflammatory response to subvert host cell functions by using various virulence factors. However, the detailed molecular mechanism, along with the identity of a target molecule, underlying the evasion of the macrophage-mediated innate immune response against S. aureus infection associated with biofilm formation remains to be elucidated. Here, using an in vitro culture model of murine macrophage-like RAW 264.7 cells, we demonstrate that S. aureus biofilm-conditioned medium significantly attenuated the capacity for macrophage bactericidal and proinflammatory responses. Importantly, the responses were associated with attenuated activation of NF-κB and increased expression of Kruppel-like factor 2 (KLF2) in RAW 264.7 cells. Small interfering RNA (siRNA)-mediated silencing of KLF2 in RAW 264.7 cells could restore the activation of NF-κB toward the bactericidal activity and generation of proinflammatory cytokines in the presence of S. aureus biofilm-conditioned medium. Collectively, our results suggest that factors secreted from S. aureus biofilms might exploit the KLF2-dependent negative regulatory mechanism to subvert macrophage-mediated innate immune defense against S. aureus biofilms.}, } @article {pmid30691287, year = {2019}, author = {Vázquez-Sánchez, D and Galvão, JA and Mazine, MR and Micotti da Gloria, E and de Souza Vieira, TMF}, title = {Anti-biofilm efficacy of single and binary treatments based on plant essential oils against Escherichia coli persistent in food-processing facilities.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {25}, number = {5}, pages = {385-393}, doi = {10.1177/1082013219826817}, pmid = {30691287}, issn = {1532-1738}, mesh = {Biofilms/*drug effects ; Disinfectants/pharmacology ; Escherichia coli/*drug effects/isolation & purification ; Food Handling/*instrumentation ; Food Microbiology/methods ; Oils, Volatile/*pharmacology ; Peracetic Acid/pharmacology ; Plant Oils/*pharmacology ; Rosmarinus/chemistry ; Sodium Hypochlorite/pharmacology ; Thymus Plant/chemistry ; }, abstract = {The efficacy of single and combined treatments based on plant essential oils was investigated against Escherichia coli strains persistent in food-processing facilities. Surface materials (stainless steel and polystyrene), disinfectants (peracetic acid and sodium hypochlorite), and conditions (25 ℃, frequency of sanitizing of 24 h) commonly present in the food industry were also used to reach a more realistic approach. Thyme and pepper-rosmarin oils were significantly (P < 0.05) very effective against planktonic cells and biofilms formed by strains E6 and E7, respectively, followed by peracetic acid. Meanwhile, craveiro oil showed an efficacy that is significantly (P < 0.05) higher than sodium hypochlorite. All these disinfectants except sodium hypochlorite were able to kill 99.99% of biofilm cells in the range of concentrations tested (0.1%-3% v/v). However, binary treatments were needed to decrease the doses of these essential oils significantly (P < 0.05) for the control of E. coli biofilms. The effectiveness of peracetic acid against E. coli biofilms was also improved by blending with these essential oils. In particular, blends of pepper-rosmarin with thyme or peracetic acid demonstrated a suitable effectiveness for the control of persistent E. coli present in food-related environments. The application of these treatments could also reduce the current environmental impact generated during food-processing sanitization.}, } @article {pmid30691200, year = {2019}, author = {Nielsen, SM and Penstoft, LN and Nørskov-Lauritsen, N}, title = {Motility, Biofilm Formation and Antimicrobial Efflux of Sessile and Planktonic Cells of Achromobacter xylosoxidans.}, journal = {Pathogens (Basel, Switzerland)}, volume = {8}, number = {1}, pages = {}, pmid = {30691200}, issn = {2076-0817}, support = {R146-2012-12145//Lundbeckfonden/ ; }, abstract = {Achromobacter xylosoxidans is an innately multidrug-resistant bacterium capable of forming biofilms in the respiratory tract of cystic fibrosis (CF) patients. During the transition from the planktonic stage to biofilm growth, bacteria undergo a transcriptionally regulated differentiation. An isolate of A. xylosoxidans cultured from the sputum of a CF patient was separated into sessile and planktonic stages in vitro, and the transcriptomes were compared. The selected genes of interest were subsequently inactivated, and flagellar motility was found to be decisive for biofilm formation in vitro. The spectrum of a new resistance-nodulation-cell division (RND)-type multidrug efflux pump (AxyEF-OprN) was characterized by inactivation of the membrane fusion protein. AxyEF-OprN is capable of extruding some fluoroquinolones (levofloxacin and ciprofloxacin), tetracyclines (doxycycline and tigecycline) and carpabenems (ertapenem and imipenem), which are classes of antimicrobials that are widely used for treatment of CF pulmonary infections.}, } @article {pmid30691087, year = {2019}, author = {Rodrigues, CF and Correia, A and Vilanova, M and Henriques, M}, title = {Inflammatory Cell Recruitment in Candida glabrata Biofilm Cell-Infected Mice Receiving Antifungal Chemotherapy.}, journal = {Journal of clinical medicine}, volume = {8}, number = {2}, pages = {}, pmid = {30691087}, issn = {2077-0383}, support = {UID/BIO/04469/2013//Fundação para a Ciência e a Tecnologia/ ; }, abstract = {(1) Background: Due to a high rate of antifungal resistance, Candida glabrata is one of the most prevalent Candida spp. linked to systemic candidiasis, which is particularly critical in catheterized patients. The goal of this work was to simulate a systemic infection exclusively derived from C. glabrata biofilm cells and to evaluate the effectiveness of the treatment of two echinocandins-caspofungin (Csf) and micafungin (Mcf). (2) Methods: CD1 mice were infected with 48 h-biofilm cells of C. glabrata and then treated with Csf or Mcf. After 72 h, the efficacy of each drug was evaluated to assess the organ fungal burden through colony forming units (CFU) counting. The immune cell recruitment into target organs was evaluated by flow cytometry or histopathology analysis. (3) Results: Fungal burden was found to be higher in the liver than in the kidneys. However, none of the drugs was effective in completely eradicating C. glabrata biofilm cells. At the evaluated time point, flow cytometry analysis showed a predominant mononuclear response in the spleen, which was also evident in the liver and kidneys of the infected mice, as observed by histopathology analysis. (4) Conclusions: Echinocandins do not have a significant impact on liver and kidney fungal burden, or recruited inflammatory infiltrate, when mice are intravenously (i.v.) infected with C. glabrata biofilm-grown cells.}, } @article {pmid30690787, year = {2019}, author = {Kugadas, A and Geddes-McAlister, J and Guy, E and DiGiandomenico, A and Sykes, DB and Mansour, MK and Mirchev, R and Gadjeva, M}, title = {Frontline Science: Employing enzymatic treatment options for management of ocular biofilm-based infections.}, journal = {Journal of leukocyte biology}, volume = {105}, number = {6}, pages = {1099-1110}, pmid = {30690787}, issn = {1938-3673}, support = {R01 EY022054/EY/NEI NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; *Cornea/metabolism/microbiology/pathology ; Eye Infections, Bacterial/*metabolism/microbiology/pathology ; Mice ; Neutrophils/*metabolism/pathology ; Pseudomonas Infections/*metabolism/pathology ; Pseudomonas aeruginosa/*physiology ; Species Specificity ; }, abstract = {Pseudomonas aeruginosa-induced corneal keratitis is a sight-threatening disease. The rise of antibiotic resistance among P. aeruginosa keratitis isolates makes treatment of this disease challenging, emphasizing the need for alternative therapeutic modalities. By comparing the responses to P. aeruginosa infection between an outbred mouse strain (Swiss Webster, SW) and a susceptible mouse strain (C57BL6/N), we found that the inherent neutrophil-killing abilities of these strains correlated with their susceptibility to infection. Namely, SW-derived neutrophils were significantly more efficient at killing P. aeruginosa in vitro than C57BL6/N-derived neutrophils. To interrogate whether the distinct neutrophil killing capacities were dependent on endogenous or exogenous factors, neutrophil progenitor cell lines were generated. The in vitro differentiated neutrophils from either SW or C57BL6/N progenitors retained the differential killing abilities, illustrating that endogenous factors conferred resistance. Consistently, quantitative LC-MS/MS analysis revealed strain-specific and infection-induced alterations of neutrophil proteomes. Among the distinctly elevated proteins in the SW-derived proteomes were α-mannosidases, potentially associated with protection. Inhibition of α-mannosidases reduced neutrophil bactericidal functions in vitro. Conversely, topical application of α-mannosidases reduced bacterial biofilms and burden of infected corneas. Cumulatively, these data suggest novel therapeutic approaches to control bacterial biofilm assembly and improve bacterial clearance via enzymatic treatments.}, } @article {pmid30689756, year = {2019}, author = {Ząbczyk, M and Natorska, J and Zalewski, J and Undas, A}, title = {Fibrin biofilm can be detected on intracoronary thrombi aspirated from patients with acute myocardial infarction.}, journal = {Cardiovascular research}, volume = {115}, number = {6}, pages = {1026-1028}, doi = {10.1093/cvr/cvz019}, pmid = {30689756}, issn = {1755-3245}, mesh = {*Biofilms ; Coronary Thrombosis/microbiology/*pathology/therapy ; Fibrin/*ultrastructure ; Humans ; Microscopy, Electron, Scanning ; ST Elevation Myocardial Infarction/microbiology/*pathology/therapy ; Suction ; Surface Properties ; Thrombectomy ; }, } @article {pmid30689669, year = {2019}, author = {Weiland-Bräuer, N and Malek, I and Schmitz, RA}, title = {Metagenomic quorum quenching enzymes affect biofilm formation of Candida albicans and Staphylococcus epidermidis.}, journal = {PloS one}, volume = {14}, number = {1}, pages = {e0211366}, pmid = {30689669}, issn = {1932-6203}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Candida albicans/*genetics/isolation & purification ; Candidiasis/microbiology ; Humans ; *Metagenomics ; *Quorum Sensing ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*genetics/isolation & purification ; }, abstract = {Biofilm formation in the clinical environment is of increasing concern since a significant part of human infections is associated, and caused by biofilm establishment of (opportunistic) pathogens, for instance Candida albicans and Staphylococcus epidermidis. The rapidly increasing number of antibiotic-resistant biofilms urgently requires the development of novel and effective strategies to prevent biofilm formation ideally targeting a wide range of infectious microorganisms. Both, synthesis of extracellular polymeric substances and quorum sensing are crucial for biofilm formation, and thus potential attractive targets to combat undesirable biofilms.We evaluated the ability of numerous recently identified metagenome-derived bacterial quorum quenching (QQ) proteins to inhibit biofilm formation of C. albicans and S. epidermidis. Here, proteins QQ-5 and QQ-7 interfered with the morphogenesis of C. albicans by inhibiting the yeast-to-hyphae transition, ultimately leading to impaired biofilm formation. Moreover, QQ5 and QQ-7 inhibited biofilm formation of S. epidermidis; in case of QQ7 most likely due to induced expression of the icaR gene encoding the repressor for polysaccharide intercellular adhesin (PIA) synthesis, the main determinant for staphylococcal biofilm formation. Our results indicate that QQ-5 and QQ-7 are attractive potential anti-biofilm agents in the prevention and treatment of C. albicans and S. epidermidis mono-species biofilms, and potentially promising anti-biofilm drugs in also combating multi-species infections.}, } @article {pmid30687745, year = {2018}, author = {Piechota, M and Kot, B and Frankowska-Maciejewska, A and Grużewska, A and Woźniak-Kosek, A}, title = {Biofilm Formation by Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains from Hospitalized Patients in Poland.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {4657396}, pmid = {30687745}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Genes, Bacterial/genetics ; Humans ; Methicillin/pharmacology ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*isolation & purification ; Microbial Sensitivity Tests/methods ; Operon/genetics ; Poland ; Staphylococcal Infections/drug therapy/microbiology ; }, abstract = {Biofilm-mediated infections in the hospital environment have a significant negative impact on patient health. This study aimed to investigate biofilm production in vitro and the presence of icaABCD genes in methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains isolated from hospitalized patients. MRSA (73) and MSSA (57) strains were evaluated for biofilm production by the microtiter plate method. The presence of ica operon was investigated by PCR. Out of 130 strains, 99.2% were biofilm producers. Strong biofilms were formed by 39.7% of MRSA and 36.8% of MSSA strains. The highest percentage of strong biofilm producers was found among the strains isolated from sputum and tracheostomy tube (66.7%), nose and catheter (50%), throat (44.4%), and bronchoalveolar washings (43.8%). The strains isolated from bronchoalveolar washings produced significantly more biofilm than strains isolated from wound and anus. The ability of biofilm forming by fecal strains was significantly lower compared to strains from other materials. MRSA strains had significantly higher ability of biofilm formation than MSSA strains (P = 0.000247). The presence of ica operon in MRSA was detected in all strains. Comparison of strong biofilm biomass of the strains with icaABCD, icaABD, and icaAD revealed that strains with icaABCD and icaABD produced highly significantly more biofilm than strains with icaAD. Biofilm forming by both MRSA and MSSA strains indicates high ability of theses strains to persist in hospital environment which increases the risk of disease development in hospitalized patients.}, } @article {pmid30687295, year = {2018}, author = {Li, T and Mei, Y and He, B and Sun, X and Li, J}, title = {Reducing Quorum Sensing-Mediated Virulence Factor Expression and Biofilm Formation in Hafnia alvei by Using the Potential Quorum Sensing Inhibitor L-Carvone.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3324}, pmid = {30687295}, issn = {1664-302X}, abstract = {Quorum sensing (QS), one of the most remarkable microbiological discoveries, is considered a global gene regulatory mechanism for various traits in bacteria, including virulence and spoilage. Hafnia alvei, an opportunistic pathogen and a dominant psychrophile, uses the lux-type QS system to regulate the production of virulence factors and biofilms, which are harmful to the food industry. Based on the QS interference approach, this study aimed to reveal the efficacy of L-carvone at sublethal concentrations on QS-regulated virulence factors and biofilm formation in H. alvei. QS inhibitory activity was demonstrated by the reduction in swinging motility (61.49%), swarming motility (74.94%), biofilm formation (52.41%) and acyl-homoserine lactone (AHL) production (0.5 μL/mL). Additionally, in silico analysis and RT-qPCR studies for AHL synthase HalI and QS transcriptional regulator HalR revealed a plausible molecular mechanism for QS inhibition by L-carvone. These findings suggest that L-carvone (a main component of spearmint essential oils) could be used as a novel quorum sensing inhibitor to control H. alvei in the food industry.}, } @article {pmid30687283, year = {2018}, author = {Su, Y and Tang, K and Liu, J and Wang, Y and Zheng, Y and Zhang, XH}, title = {Quorum Sensing System of Ruegeria mobilis Rm01 Controls Lipase and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3304}, pmid = {30687283}, issn = {1664-302X}, abstract = {Quorum sensing (QS) promotes in situ extracellular enzyme (EE) activity via the exogenous signal N-acylhomoserine lactone (AHL), which facilitates marine particle degradation, but the species that engage in this regulatory mechanism remain unclear. Here, we obtained AHL-producing and AHL-degrading strains from marine particles. The strain Ruegeria mobilis Rm01 of the Roseobacter group (RBG), which was capable of both AHL producing and degrading, was chosen to represent these strains. We demonstrated that Rm01 possessed a complex QS network comprising AHL-based QS and quorum quenching (QQ) systems and autoinducer-2 (AI-2) perception system. Rm01 was able to respond to multiple exogenous QS signals through the QS network. By applying self-generated AHLs and non-self-generated AHLs and AI-2 QS signal molecules, we modulated biofilm formation and lipase production in Rm01, which reflected the coordination of bacterial metabolism with that of other species via eavesdropping on exogenous QS signals. These results suggest that R. mobilis might be one of the participators that could regulate EE activities by responding to QS signals in marine particles.}, } @article {pmid30687268, year = {2018}, author = {Liu, C and Sun, D and Zhu, J and Liu, W}, title = {Two-Component Signal Transduction Systems: A Major Strategy for Connecting Input Stimuli to Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3279}, pmid = {30687268}, issn = {1664-302X}, abstract = {Biofilms are multicellular communities of microbes that are encased within an extracellular matrix. Environmental factors induce bacteria to form biofilm. Bacteria have several regulatory mechanisms in response to environmental changes, and the two-component signal transduction system (TCS) is a major strategy in connecting changes in input signals to changes in cellular physiological output. The TCS employs multiple mechanisms such as cross-regulation, to integrate and coordinate various input stimuli to control biofilm formation. In this mini-review, we demonstrate the roles of TCS on biofilm formation, illustrating these input signals and modulation modes, which may be utilized by future investigations in elucidating the regulatory signals and underlying the mechanisms of biofilm formation.}, } @article {pmid30687262, year = {2018}, author = {Zhou, C and Ontiveros-Valencia, A and Nerenberg, R and Tang, Y and Friese, D and Krajmalnik-Brown, R and Rittmann, BE}, title = {Hydrogenotrophic Microbial Reduction of Oxyanions With the Membrane Biofilm Reactor.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {3268}, pmid = {30687262}, issn = {1664-302X}, abstract = {Oxyanions, such as nitrate, perchlorate, selenate, and chromate are commonly occurring contaminants in groundwater, as well as municipal, industrial, and mining wastewaters. Microorganism-mediated reduction is an effective means to remove oxyanions from water by transforming oxyanions into harmless and/or immobilized forms. To carry out microbial reduction, bacteria require a source of electrons, called the electron-donor substrate. Compared to organic electron donors, H2 is not toxic, generates minimal secondary contamination, and can be readily obtained in a variety of ways at reasonable cost. However, the application of H2 through conventional delivery methods, such as bubbling, is untenable due to H2's low water solubility and combustibility. In this review, we describe the membrane biofilm reactor (MBfR), which is a technological breakthrough that makes H2 delivery to microorganisms efficient, reliable, and safe. The MBfR features non-porous gas-transfer membranes through which bubbleless H2 is delivered on-demand to a microbial biofilm that develops naturally on the outer surface of the membranes. The membranes serve as an active substratum for a microbial biofilm able to biologically reduce oxyanions in the water. We review the development of the MBfR technology from bench, to pilot, and to commercial scales, and we elucidate the mechanisms that control MBfR performance, particularly including methods for managing the biofilm's structure and function. We also give examples of MBfR performance for cases of treating single and co-occurring oxyanions in different types of contaminated water. In summary, the MBfR is an effective and reliable technology for removing oxyanion contaminants by accurately providing a biofilm with bubbleless H2 on demand. Controlling the H2 supply in accordance to oxyanion surface loading and managing the accumulation and activity of biofilm are the keys for process success.}, } @article {pmid30686747, year = {2019}, author = {Carrano, G and Paulone, S and Lainz, L and Sevilla, MJ and Blasi, E and Moragues, MD}, title = {Anti-Candidaalbicans germ tube antibodies reduce in vitro growth and biofilm formation of C. albicans.}, journal = {Revista iberoamericana de micologia}, volume = {36}, number = {1}, pages = {9-16}, doi = {10.1016/j.riam.2018.07.005}, pmid = {30686747}, issn = {2173-9188}, mesh = {Antibodies, Fungal/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/growth & development/*physiology ; Fungal Structures/*immunology ; Mycology/methods ; }, abstract = {BACKGROUND: Invasive candidiasis by Candida albicans is associated with high morbidity and mortality, due in part to the late implementation of an appropriate antifungal therapy hindered by the lack of an early diagnosis.

AIMS: We aimed to evaluate the in vitro antifungal activity of the antibodies against C. albicans germ tubes (CAGTA) raised in a rabbit model of candidemia.

METHODS: We measured the effect of CAGTA activity by colorimetric XTT and crystal violet assays, and colony forming units count, both on C. albicans planktonic cells and during the course of biofilm formation and maturation. Viability and cell morphology were assessed by optical, fluorescent or scanning electron microscopy.

RESULTS: CAGTA ≥50μg/ml caused a strong inhibition of C. albicans blastospores growth, and DiBAC fluorescent staining evidenced a fungicidal activity. Moreover, electron microscopy images revealed that CAGTA induced morphological alterations of the surface of C. albicans germ tubes grown free as well as in biofilm. Interestingly, CAGTA ≥80μg/ml reduced the amount of C. albicans biofilm, and this effect started at the initial adhesion stage of the biofilm formation, during the first 90min.

CONCLUSIONS: This is the first report showing that CAGTA reduce C. albicans growth, and impair its metabolic activity and ability to form biofilm in vitro. The antigens recognized by CAGTA could be the basis for the development of immunization protocols that might protect against Candida infections.}, } @article {pmid30685725, year = {2019}, author = {Sridhar, S and Wang, F and Wilson, TG and Palmer, K and Valderrama, P and Rodrigues, DC}, title = {The role of bacterial biofilm and mechanical forces in modulating dental implant failures.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {92}, number = {}, pages = {118-127}, doi = {10.1016/j.jmbbm.2019.01.012}, pmid = {30685725}, issn = {1878-0180}, mesh = {Bacteria/metabolism ; *Bacterial Physiological Phenomena ; *Biofilms ; Dental Implants/*microbiology ; Materials Testing ; *Mechanical Phenomena ; Oxides/metabolism ; *Prosthesis Failure ; Surface Properties ; }, abstract = {Currently many assume that bacteria are the primary etiological factor associated with failure of titanium dental implants. However, emerging data indicates a possible role for mechanical forces in implant failure. This study is based on the hypothesis that the synergistic effect of mechanical forces and bacterial biofilm can lead to surface damage resulting in in vivo release of metallic particles. The primary aim of the study was to develop a dynamic fatigue test method for dental implants immersed in wet environments such as; (i) 0.01 M phosphate buffer saline (PBS); (ii) lactic acid (pH = 5); (iii) bacterial polyculture. Four dental implants each were subjected to fatigue loading from 45 N to 450 N at 4 Hz for 2 million cycles while immersed in (i) PBS (negative control); (ii) bacterial culture (test); and (iii) lactic acid (positive control). Post-testing, optical microscopy, x-ray photoelectron spectroscopy, and electrochemical corrosion tests were performed to evaluate the surface morphology, chemistry, and potential, respectively, of titanium implants. Post-testing, surface discoloration was evident in all three groups. However, the surface damage was further established in XPS analyses of test specimens, which showed that the interplay of bacterial biofilm and mechanical forces resulted in thinning of the TiO2. Lower corrosion potential (Ecorr) of the test specimens compared to positive and negative controls also illustrated damage to the oxide layer. However, other electrochemical parameters such as linear polarization resistance (LPR) and corrosion rate (CR) were comparable among the groups indicating the corrosion resistance post-testing. The synergistic effect of cyclic occlusal loading and bacteria biofilm could negatively affect the surface of titanium dental implants.}, } @article {pmid30685290, year = {2019}, author = {Sheng, X and Wang, W and Chen, L and Zhang, H and Zhang, Y and Xu, S and Xu, H and Huang, X}, title = {Mig-14 may contribute to Salmonella enterica serovar Typhi resistance to polymyxin B by decreasing the permeability of the outer-membrane and promoting the formation of biofilm.}, journal = {International journal of medical microbiology : IJMM}, volume = {309}, number = {2}, pages = {143-150}, doi = {10.1016/j.ijmm.2019.01.001}, pmid = {30685290}, issn = {1618-0607}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cell Membrane/*drug effects ; *Drug Resistance, Bacterial ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Permeability ; Polymyxin B/*pharmacology ; Salmonella typhi/*drug effects/genetics/growth & development ; }, abstract = {Mig-14 is essential for Salmonella enterica serovar Typhimurium (S. Typhimurium) resistance to antimicrobial peptides, including polymyxin B (PB). However, the molecular mechanism is as yet unknown. In this study, we demonstrated that mig-14 also played a crucial role in Salmonella enterica serovar Typhi (S. Typhi) resistance to PB. A series of genes associated with drug-resistance controlled by Mig-14 were identified in the presence of PB. Among which, ompF and ompC were up-regulated 8 and 6 folds in mig-14 mutant (Δmig-14) strains, respectively. Further, the deletion of ompF or/and ompC in Δmig-14 strains decreased their sensitivity to PB. Besides, the biofilm formation ability was reduced in Δmig-14 strains. Our results indicate that Mig-14 may contribute to PB resistance in S. Typhi by decreasing the permeability of the outer membrane and promoting biofilm formation.}, } @article {pmid30684672, year = {2019}, author = {Mahmoudi, H and Pourhajibagher, M and Alikhani, MY and Bahador, A}, title = {The effect of antimicrobial photodynamic therapy on the expression of biofilm associated genes in Staphylococcus aureus strains isolated from wound infections in burn patients.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {25}, number = {}, pages = {406-413}, doi = {10.1016/j.pdpdt.2019.01.028}, pmid = {30684672}, issn = {1873-1597}, mesh = {ATP Binding Cassette Transporter, Subfamily D/drug effects ; Biofilms/*drug effects ; Burns/*microbiology ; Dose-Response Relationship, Drug ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics ; Microbial Sensitivity Tests ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Real-Time Polymerase Chain Reaction ; Staphylococcus aureus/*drug effects/genetics ; Tolonium Chloride/pharmacology ; Wound Infection/*microbiology ; }, abstract = {PURPOSE: Burn patients are particularly susceptible to microbial infection. Staphylococcus aureus causes burn wound, impetigo and cellulitis. Although sub-lethal antimicrobial photodynamic therapy (aPDT) would not result in microorganism killing, it can considerably influence microbial virulence factor.

METHODS: Twelve methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolated from burns patients. To determine the sub-lethal dose of aPDT, 12 clinical isolates of S. aureus photosensitized with 100 μg ml [-1] toluidine blue O (TBO) and irradiated by light emitting diode (LED) with a wavelength of 630 ± 10 nm and energy densities of 52.0, 104.1, and 156.2 J/cm[2], then bacterial viability was measured. The effects of sub-lethal aPDT on the expression levels of ica ABCD and ica R genes were assessed by quantitative Real-time PCR (qRT-PCR) method.

RESULT: Fifty and 100 μg ml[-1] of TBO significantly reduced the mean cell survival in the MRSA (2.5 - 3 log10) and MSSA (2.75-3.1 log10) isolates. The average expression levels of icaA, ica B, ica C, and ica D in the MRSA and MSSA isolates were decreased by (12, 14, 11, and 9) and (13, 14.5, 12, and 9.5) fold change, respectively (P < 0.05). However, the expression of ica R gene was decreased by 6 and 8 folds change in MRSA and MSSA, respectively.

CONCLUSION: The potential of TBO-mediated aPDT could reduce the expression of ica ABCD as important genes involved in biofilm formation and ica R gene as a repressor of the ica operon. Therefore, the use of aPDT agents as a complementary therapy in wound infections of burn patients is recommended.}, } @article {pmid30684671, year = {2019}, author = {Cai, Z and Li, Y and Wang, Y and Chen, S and Jiang, S and Ge, H and Lei, L and Huang, X}, title = {Antimicrobial effects of photodynamic therapy with antiseptics on Staphylococcus aureus biofilm on titanium surface.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {25}, number = {}, pages = {382-388}, doi = {10.1016/j.pdpdt.2019.01.024}, pmid = {30684671}, issn = {1873-1597}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Disinfection/methods ; Hydrogen Peroxide/pharmacology ; Microscopy, Electron, Scanning ; Peri-Implantitis/microbiology/prevention & control ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Staphylococcus aureus/*drug effects ; Stem Cells ; Titanium/*chemistry ; Tolonium Chloride/pharmacology ; }, abstract = {BACKGROUND: S. aureus biofilm plays a predominant role in the establishment and development of peri-implantitis. It is suggested to combine different modalities as peri-implantitis treatment. The aim of this study was to evaluate the disinfection efficacy of combined application of antiseptics with PDT on Staphylococcus aureus (S. aureus) biofilm formed on titanium(Ti) disks with different surface roughness.

METHODS: S. aureus biofilm was incubated on polished and sandblasted large-grit acid-etched (SLA) Ti surfaces for 48 h. 72 contaminated Ti disks (36 polished, 36 SLA) were randomly divided into 6 different groups as follows: (a) PBS, (b) 0.2% chlorhexidine digluconate (CHX), (c) 3% hydrogen peroxide (H2O2), (d) PDT, (e) 0.2% CHX + PDT, and (f) 3% H2O2+PDT. Colony forming unit (CFU) was measured to determine antimicrobial effects. Biofilm structure was assessed using scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM).

RESULTS: All disinfection methods significantly reduced bacteria amounts compared to control group on both polished and SLA Ti surfaces (P < 0.001). PDT demonstrated stronger decontamination ability in eliminating S. aureus from Ti surfaces than CHX and H2O2 did (P < 0.05). The combined CHX or H2O2 with PDT treatment were more effective in bacterial disinfection than a single administration of these treatments (P < 0.001).

CONCLUSION: The combination of CHX or H2O2 administration with PDT was more effective in eradicating S. aureus on both polished and SLA Ti disks in comparison with either treatment alone, suggesting that combined usage of antiseptics with PDT could be a more efficient method for the treatment of peri-implantitis.}, } @article {pmid30684637, year = {2019}, author = {Chokpaisarn, J and Yincharoen, K and Sanpinit, S and Karutha Pandian, ST and Nandhini, JR and Gowrishankar, S and Limsuwan, S and Kunworarath, N and Voravuthikunchai, SP and Chusri, S}, title = {Effects of a traditional Thai polyherbal medicine 'Ya-Samarn-Phlae' as a natural anti-biofilm agent against Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {128}, number = {}, pages = {354-362}, doi = {10.1016/j.micpath.2019.01.036}, pmid = {30684637}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Drugs, Chinese Herbal/chemistry/*pharmacology ; *Medicine, Traditional ; Microbial Sensitivity Tests ; Plant Oils/chemistry/pharmacology ; Pseudomonas aeruginosa/*drug effects ; Thailand ; Wound Infection ; Xanthones/pharmacology ; }, abstract = {Ya-Samarn-Phlae (YaSP) is a traditional Thai polyherbal formula for the treatment of chronic wounds. Although its ethanol extract has been proven to possess several wound-related biological activities, there is no scientific information available for the infused oil of YaSP, which is its traditionally prepared form. This present study therefore aimed to evaluate the efficacy of different infused oils obtained from either fresh or oven-dried herbal parts of YaSP (F-YaSP and D-YaSP) against biofilms of Pseudomonas aeruginosa, which reside in chronic wounds. Its main active herbal component, Garcinia mangostana (F-GM and D-GM), as well as α-mangostin were also tested in this study. All infused oils significantly inhibited the biofilm formation of P. aeruginosa with a percentage of reduction ranging from 50 to 90%. Visualization of the inhibition of biofilm development was confirmed using scanning electron and atomic force microscopes. All tested agents resulted in a reduction in the mean average roughness of the biofilm, whereas only treating with D-YaSP, D-GM, and α-mangostin led to a decrease in both peak height and peak-valley height. MTT reduction assays revealed that the metabolic activity of P. aeruginosa mature biofilms decreased considerably up to 50% after only 3 h of incubation and after only 9 h of exposure to D-YaSP. Confocal laser scanning micrographs illustrated that a maximum biofilm eradication was found when treated with the extracts for 3 h, whereas the biomass, the average thickness, maximum thickness, and the surface to volume ratio of the treated biofilm was reduced after up to 18 h of contact time. It can be concluded that D-YaSP can effectively inhibit biofilm formation and eradicate mature biofilms of P. aeruginosa. It should be noted that G. mangostana and α-mangostin contribute in YaSP as principle active agents for anti-biofilm efficacy.}, } @article {pmid30683036, year = {2019}, author = {Akışoğlu, Ö and Engin, D and Sarıçam, S and Müştak, HK and Şener, B and Hasçelik, G}, title = {[Multilocus sequence analysis, biofilm production, antibiotic susceptibility and synergy tests of Burkholderia species in patients with and without cystic fibrosis].}, journal = {Mikrobiyoloji bulteni}, volume = {53}, number = {1}, pages = {22-36}, doi = {10.5578/mb.67730}, pmid = {30683036}, issn = {0374-9096}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Biofilms ; *Burkholderia/drug effects/genetics/physiology ; *Cystic Fibrosis/microbiology ; Humans ; Microbial Sensitivity Tests ; *Multilocus Sequence Typing ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {Burkholderia spp. emerged as important pathogens in the airways of immunocompromised humans, especially those with cystic fibrosis (CF). Failure of identification with conventional techniques, high intrinsic resistance to most antibiotics and biofilm formation can cause difficulties in the treatment of these infections. The aim of this study was to identify Burkholderia spp. strains isolated from CF and non-CF patients with with routine microbiological methods, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and multilocus sequence analysis (MLSA), to determine of the antibiotic susceptibility and synergies, and to evaluate biofilm formation of these isolates. A total of 38 Burkholderia spp. (25 CF, 13 non-CF) from 26 patients were identified by biochemical, phenotypical and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and sequence types were revealed by multilocus sequence analysis (MLSA). Sequence types of isolates were identified using the PubMLST database. Characteristics of biofilm formation of clinical isolates were evaluated by microplate method. Antibiotic susceptibilities of ceftazidime, meropenem, trimethoprim-sulfamethoxazole (TMP-SXT) and levofloxacin were determined by broth microdilution method according to CLSI (2017) guidelines. Synergy tests were performed by checkerboard method. Clinical isolates were identified as Burkholderia cenocepacia (n= 16), Burkholderia contaminans (n= 11), Burkholderia gladioli (n= 4), Burkholderia dolosa (n= 4), Burkholderia multivorans (n= 2) and Burkholderia seminalis (n= 1). Sequence types of these isolates were determined as ST19, ST72, ST102, ST180, ST482, ST602, ST629, ST740, ST839 and ST1392. The correct identification at the species-level with MALDI-TOF MS was 94-100% for all isolates except B.contaminans. Biofilm formation among the identified species in the study was determined as 53% (n= 20). There was no statistical difference when the biofilm production was evaluated separately among Burkholderia species and biofilm production rates between CF (56%, 14/25) and non-CF (46%, 6/13) Burkholderia isolates (p> 0.05). Overall rates of resistance to ceftazidime, meropenem, TMP-SXT, and levofloxacin of the isolates were 35%, 66%, 50% and 40%, respectively. The antibiotic resistance against Burkholderia spp., isolates obtained from CF patients were more susceptible to ceftazidime, but no significant difference was found for other antibiotics. Synergy was determined between meropenem and TMP-SXT in two isolates. Antagonism was detected in 15 isolates, 12 of them were between meropenem and ceftazidime, three of them were between ceftazidime and TMP-SXT. Numerous resistance mechanisms may lead to higher resistance in this bacteria, whereas the antagonism between meropenem and ceftazidime in this study might be attributed to the expression of beta-lactamases. In this study, the distinctness of sequence types between Burkholderia spp. isolated from CF and non-CF patient, provided a better understanding about the importance of biofilm formation for the infections with these bacteria and emphasized that the management of therapy should be driven by the antibiotic test results.}, } @article {pmid30682497, year = {2019}, author = {Gómez-Junyent, J and Benavent, E and Sierra, Y and El Haj, C and Soldevila, L and Torrejón, B and Rigo-Bonnin, R and Tubau, F and Ariza, J and Murillo, O}, title = {Efficacy of ceftolozane/tazobactam, alone and in combination with colistin, against multidrug-resistant Pseudomonas aeruginosa in an in vitro biofilm pharmacodynamic model.}, journal = {International journal of antimicrobial agents}, volume = {53}, number = {5}, pages = {612-619}, doi = {10.1016/j.ijantimicag.2019.01.010}, pmid = {30682497}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects/growth & development ; Cephalosporins/*administration & dosage ; Colistin/*administration & dosage ; Drug Resistance, Bacterial ; Drug Therapy, Combination/methods ; Humans ; Models, Theoretical ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects/growth & development ; Tazobactam/*administration & dosage ; beta-Lactamase Inhibitors/*administration & dosage ; }, abstract = {OBJECTIVES: Ceftolozane/tazobactam is a potential tool for infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa), but its efficacy against some difficult-to-treat infections has not been well defined.

METHODS: Using an in vitro pharmacodynamic biofilm model, this study evaluated the comparative efficacy of ceftolozane/tazobactam against MDR/extensively drug-resistant (XDR) P. aeruginosa strains, alone and in combination with colistin. Simulated regimens of ceftolozane/tazobactam (2 g/1 g every 8 h), meropenem (2 g every 8 h) and ceftazidime (2 g every 8 h), alone and in combination with colistin (continuous infusion) were evaluated against three colistin-susceptible and ceftazidime-resistant strains: MDR-HUB1, ceftolozane/tazobactam-susceptible and meropenem-susceptible; XDR-HUB2, ceftolozane/tazobactam-susceptible and meropenem-resistant; MDR-HUB3, ceftolozane/tazobactam-resistant and meropenem-susceptible. Antibiotic efficacy was evaluated by decreases in bacterial counts (Δlog CFU/mL) from biofilm-embedded bacteria over 54 h. Resistance emergence was screened.

RESULTS: Among monotherapies, ceftolozane/tazobactam had low killing but no resistance appeared, ceftazidime was ineffective, colistin was initially effective but regrowth and resistance occurred, and meropenem was bactericidal against carbapenem-susceptible strains. Ceftolozane/tazobactam plus colistin was the most effective combination against the meropenem-resistant XDR-HUB2 strain (Δlog CFU/mL 54-0 h = -4.42 vs. -3.54 for meropenem-colistin; P = 0.002), whereas this combination against MDR-HUB1 (-4.36) was less effective than meropenem-colistin (-6.25; P < 0.001). Ceftolozane/tazobactam plus colistin was ineffective against the ceftolozane/tazobactam-resistant strain; meropenem plus colistin was the most bactericidal therapy (-6.37; P < 0.001 vs. others). Combinations of active beta-lactams plus colistin prevented the emergence of colistin-resistant strains.

CONCLUSIONS: Combinations of colistin plus ceftolozane/tazobactam and meropenem were the most appropriate treatments for biofilm-related infections caused by XDR and MDR P. aeruginosa strains, respectively. These combinations could be considered as potential treatment options for these difficult to treat infections.}, } @article {pmid30682094, year = {2019}, author = {Loza-Correa, M and Ayala, JA and Perelman, I and Hubbard, K and Kalab, M and Yi, QL and Taha, M and de Pedro, MA and Ramirez-Arcos, S}, title = {The peptidoglycan and biofilm matrix of Staphylococcus epidermidis undergo structural changes when exposed to human platelets.}, journal = {PloS one}, volume = {14}, number = {1}, pages = {e0211132}, pmid = {30682094}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Blood Platelets/*metabolism/microbiology/pathology ; Humans ; Peptidoglycan/*metabolism ; Staphylococcus epidermidis/*physiology ; }, abstract = {Staphylococcus epidermidis is a bacterium frequently isolated from contaminated platelet concentrates (PCs), a blood product used to treat bleeding disorders in transfusion patients. PCs offer an accidental niche for colonization of S. epidermidis by forming biofilms and thus avoiding clearance by immune factors present in this milieu. Using biochemical and microscopy techniques, we investigated the structural changes of the peptidoglycan (PG) and the biofilm matrix of S. epidermidis biofilms formed in whole-blood derived PCs compared to biofilms grown in glucose-supplemented trypticase soy broth (TSBg). Both, the PG and the biofilm matrix are primary mechanisms of defense against environmental stress. Here we show that in PCs, the S. epidermidis biofilm matrix is mainly of a proteinaceous nature with extracellular DNA, in contrast to the predominant polysaccharide nature of the biofilm matrix formed in TSBg cultures. PG profile studies demonstrated that the PG of biofilm cells remodels during PC storage displaying fewer muropeptides variants than those observed in TSBg. The PG muropeptides contain two chemical modifications (amidation and O-acetylation) previously associated with resistance to antimicrobial agents by other staphylococci. Our study highlights two key structural features of S. epidermidis that are remodeled when exposed to human platelets and could be used as targets to reduce septic transfusions events.}, } @article {pmid30681888, year = {2019}, author = {Marczak, M and Żebracki, K and Koper, P and Turska-Szewczuk, A and Mazur, A and Wydrych, J and Wójcik, M and Skorupska, A}, title = {Mgl2 Is a Hypothetical Methyltransferase Involved in Exopolysaccharide Production, Biofilm Formation, and Motility in Rhizobium leguminosarum bv. trifolii.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {32}, number = {7}, pages = {899-911}, doi = {10.1094/MPMI-01-19-0026-R}, pmid = {30681888}, issn = {0894-0282}, mesh = {*Biofilms/growth & development ; *Methyltransferases/metabolism ; Nitrogen Fixation ; Polysaccharides, Bacterial/genetics ; *Rhizobium leguminosarum/enzymology/genetics ; }, abstract = {In this study, functional characterization of the mgl2 gene located near the Pss-I exopolysaccharide biosynthesis region in Rhizobium leguminosarum bv. trifolii TA1 is described. The hypothetical protein encoded by the mgl2 gene was found to be similar to methyltransferases (MTases). Protein homology and template-based modeling facilitated prediction of the Mgl2 structure, which greatly resembled class I MTases with a S-adenosyl-L-methionine-binding cleft. The Mgl2 protein was engaged in exopolysaccharide, but not lipopolysaccharide, synthesis. The mgl2 deletion mutant produced exopolysaccharide comprised of only low molecular weight fractions, while overexpression of mgl2 caused overproduction of exopolysaccharide with a normal low to high molecular weight ratio. The deletion of the mgl2 gene resulted in disturbances in biofilm formation and a slight increase in motility in minimal medium. Red clover (Trifolium pratense) inoculated with the mgl2 mutant formed effective nodules, and the appearance of the plants indicated active nitrogen fixation. The mgl2 gene was preceded by an active and strong promoter. Mgl2 was defined as an integral membrane protein and formed homodimers in vivo; however, it did not interact with Pss proteins encoded within the Pss-I region. The results are discussed in the context of the possible involvement of the newly described potential MTase in various metabolic traits, such as the exopolysaccharide synthesis and motility that are important for rhizobial saprophytic and symbiotic relationships.}, } @article {pmid30680979, year = {2019}, author = {Avdić, M and Džuzić, N and Hasanić, O and Spahić, A and Smajlović Skenderagić, L and Badnjević, A and Hukić, M}, title = {Development of a novel biofilm classification tool and comparative analysis of result interpretation methodologies for the evaluation of biofilm forming capacity of bacteria using tissue culture plate method.}, journal = {Medicinski glasnik : official publication of the Medical Association of Zenica-Doboj Canton, Bosnia and Herzegovina}, volume = {16}, number = {1}, pages = {13-21}, doi = {10.17392/997-19}, pmid = {30680979}, issn = {1840-2445}, mesh = {Bacteria/*growth & development ; Bacteriological Techniques/*methods ; Biofilms/*classification ; Enzyme-Linked Immunosorbent Assay ; Humans ; Optical Phenomena ; Predictive Value of Tests ; Reference Values ; Sensitivity and Specificity ; Tissue Culture Techniques/*methods ; }, abstract = {Aim To develop an online biofilm calculation tool (Biofilm Classifier), which calculates the optical density cut off value and accordingly determines the biofilm forming categories for the tested isolates by standardized formulas, as well as to compare the results obtained by Biofilm Classifier to manual calculations and the use of predefined values. Methods The biofilm forming capacity of tested strains was evaluated using tissue culture plate method in 96 well plates, and optical density (OD) value of the formed biofilm was measured on an ELISA Microplate reader at 595 nm on a total of 551 bacterial isolates from clinical specimen. Results Comparative analysis indicated that the manual calculation was 100% in accordance with results obtained by the designed software as opposed to the results obtained by use of predefined values for biofilm categorization. When using predefined values compared to manual biofilm categorization for the determination of biofilm positive and biofilm negative strains the specificity was 100%, sensitivity 97.81%, positive predictive value 100%, negative predictive value 96.04% and accuracy 98.57%. Conclusion Considering obtained results, the use of the designed online calculator would simplify the interpretation of biofilm forming capacity of bacteria using tissue culture plate method.}, } @article {pmid30679760, year = {2019}, author = {Timmusk, S and Copolovici, D and Copolovici, L and Teder, T and Nevo, E and Behers, L}, title = {Paenibacillus polymyxa biofilm polysaccharides antagonise Fusarium graminearum.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {662}, pmid = {30679760}, issn = {2045-2322}, mesh = {*Biofilms ; Fusarium/*drug effects ; Paenibacillus polymyxa/*physiology ; Polysaccharides, Bacterial/*pharmacology ; Triticum/microbiology ; }, abstract = {Fusarium Head Blight (FHB) caused by Fusarium graminearum pathogens constitutes a major threat to agricultural production because it frequently reduces the yield and quality of the crop. The disease severity is predicted to increase in various regions owing to climate change. Integrated management where biocontrol plays an important role has been suggested in order to fight FHB. P. polymyxa A26 is known to be an effective antagonist against F. graminearum. Deeper understanding of the mode of action of P. polymyxa A26 is needed to develop strategies for its application under natural settings in order to effectively overcome the pathogenic effects. This study aims to re-evaluate a former study and reveal whether compounds other than non-ribosomal antibiotic lipopeptides could be responsible for the antagonistic effect, despite what is often reported. Wheat seedlings were grown to maturity and the spikes infected with the pathogen under greenhouse conditions. The development of FHB infection, quantified via the disease incidence severity and 100-kernel weight, was strongly correlated (r > 0.78, p < 0.01) with the content of the polysaccharide component D-glucuronic acid in the biofilm. Furthermore, while increased inoculum density from 10[6] to 10[8] cells/ml did not affect wild type performance, a significant increase was observed with the P. polymyxa mutant deficient in nonribosomal lipopeptide synthesis. Our results show that P. polymyxa A26 biofilm extracellular polysaccharides are capable of antagonizing F. graminearum and that the uronate content of the polysaccharides is of critical importance in the antagonism.}, } @article {pmid30679015, year = {2019}, author = {Agarwalla, SV and Ellepola, K and Costa, MCFD and Fechine, GJM and Morin, JLP and Castro Neto, AH and Seneviratne, CJ and Rosa, V}, title = {Hydrophobicity of graphene as a driving force for inhibiting biofilm formation of pathogenic bacteria and fungi.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {3}, pages = {403-413}, doi = {10.1016/j.dental.2018.09.016}, pmid = {30679015}, issn = {1879-0097}, mesh = {Biofilms ; Candida albicans ; *Graphite ; Hydrophobic and Hydrophilic Interactions ; Surface Properties ; }, abstract = {OBJECTIVE: To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium.

METHODS: Graphene was deposited on titanium (Control) via a liquid-free technique. The transfer was performed once (TiGS), repeated two (TiGD) and five times (TiGV) and characterized by AFM (n=10), Raman spectroscopy (n=10), contact angle and SFE (n=5). Biofilm formation (n=3) to Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans was evaluated after 24h by CV assay, CFU, XTT and confocal microscopy. Statistics were performed by one-way Anova, Tukey's tests and Pearson's correlation analysis at a pre-set significance level of 5 %.

RESULTS: Raman mappings revealed coverage yield of 82 % for TiGS and ≥99 % for TiGD and TiGV. Both TiGD and TiGV presented FWHM>44cm[-1] and ID/IG ratio<0.12, indicating multiple graphene layers and occlusion of defects. The contact angle was significantly higher for TiGD and TiGV (110° and 117°) comparing to the Control (70°). The SFE was lower for TiGD (13.8mN/m) and TiGV (12.1mN/m) comparing to Control (38.3mN/m). TiGD was selected for biofilm assays and exhibited significant reduction in biofilm formation for all microorganisms compared to Control. There were statistical correlations between the high contact angle and low SFE of TiGD and decreased biofilm formation.

SIGNIFICANCE: TiGD presented high quality and coverage and decreased biofilm formation for all species. The increased hydrophobicity of graphene films was correlated with the decreased biofilm formation for various species.}, } @article {pmid30678968, year = {2019}, author = {Takahashi, C and Hattori, Y and Yagi, S and Murai, T and Takai, C and Ogawa, N and Tanemura, M and Fuji, M and Kawashima, Y and Yamamoto, H}, title = {Optimization of ionic liquid-incorporated PLGA nanoparticles for treatment of biofilm infections.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {97}, number = {}, pages = {78-83}, doi = {10.1016/j.msec.2018.11.079}, pmid = {30678968}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry/*pharmacology ; Biofilms/*drug effects ; Drug Carriers/administration & dosage/chemistry ; Drug Delivery Systems/methods ; Imidazoles/chemistry ; Infections/drug therapy ; Ionic Liquids/*chemistry ; Microbial Sensitivity Tests/methods ; Microscopy, Electron, Scanning ; Nanoparticles/administration & dosage/*chemistry ; Poloxamer/chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer/*chemistry ; Polysorbates/chemistry ; Staphylococcus epidermidis/drug effects/physiology ; Surface-Active Agents/chemistry ; }, abstract = {Ionic liquids (ILs) containing imidazolium cations have a number of useful properties, such as high permeability to cells, high antimicrobial activity, and good biocompatibility. With the aid of ILs, transdermal delivery, solubilization of poorly soluble drugs were developed and therapeutic effects were improved. In this work, 1‑butyl‑3‑methylimidazolium hexafluorophosphate-incorporated, chitosan-modified, submicron-sized poly(dl‑lactide‑co‑glycolide) (PLGA) nanoparticles (NPs) were prepared using the emulsion solvent diffusion method for the treatment of biofilm infections. Prepared IL-incorporated PLGA NPs using surfactants such as Tween-80 and poloxamer-188 showed a high antibacterial activity to the bacterial cells under the biofilm. Additionally, antibacterial mechanism of IL-incorporated PLGA NPs was revealed by annular dark field scanning transmission electron microscopy combined a simple sample pretreatment method. We established a drug delivery system using IL-incorporated PLGA NPs to enhance the potential of polymeric nanocarriers for treating biofilm infections.}, } @article {pmid30678538, year = {2019}, author = {Ren, Z and Kim, D and Paula, AJ and Hwang, G and Liu, Y and Li, J and Daniell, H and Koo, H}, title = {Dual-Targeting Approach Degrades Biofilm Matrix and Enhances Bacterial Killing.}, journal = {Journal of dental research}, volume = {98}, number = {3}, pages = {322-330}, doi = {10.1177/0022034518818480}, pmid = {30678538}, issn = {1544-0591}, mesh = {Bacterial Adhesion ; *Biofilms ; *Dental Caries ; Extracellular Polymeric Substance Matrix ; Humans ; Streptococcus mutans ; }, abstract = {Biofilm formation is a key virulence factor responsible for a wide range of infectious diseases, including dental caries. Cariogenic biofilms are structured microbial communities embedded in an extracellular matrix that affords bacterial adhesion-cohesion and drug tolerance, making them difficult to treat using conventional antimicrobial monotherapy. Here, we investigated a multitargeted approach combining exopolysaccharide (EPS) matrix-degrading glucanohydrolases with a clinically used essential oils-based antimicrobial to potentiate antibiofilm efficacy. Our data showed that dextranase and mutanase can synergistically break down the EPS glucan matrix in preformed cariogenic biofilms, markedly enhancing bacterial killing by the antimicrobial agent (3-log increase versus antimicrobial alone). Further analyses revealed that an EPS-degrading/antimicrobial (EDA) approach disassembles the matrix scaffold, exposing the bacterial cells for efficient killing while concurrently causing cellular dispersion and "physical collapse" of the bacterial clusters. Unexpectedly, we found that the EDA approach can also selectively target the EPS-producing cariogenic bacteria Streptococcus mutans with higher killing specificity (versus other species) within mixed biofilms, disrupting their accumulation and promoting dominance of commensal bacteria. Together, these results demonstrate a dual-targeting approach that can enhance antibiofilm efficacy and precision by dismantling the EPS matrix and its protective microenvironment, amplifying the killing of pathogenic bacteria within.}, } @article {pmid30678005, year = {2019}, author = {Huang, ZS and Wei, ZS and Xiao, XL and Tang, MR and Li, BL and Zhang, X}, title = {Simultaneous mercury oxidation and NO reduction in a membrane biofilm reactor.}, journal = {The Science of the total environment}, volume = {658}, number = {}, pages = {1465-1474}, doi = {10.1016/j.scitotenv.2018.12.105}, pmid = {30678005}, issn = {1879-1026}, mesh = {Bacteria/classification/genetics ; *Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/*microbiology ; DNA, Bacterial/analysis ; Denitrification ; Membranes, Artificial ; Mercury/*metabolism ; Metagenome ; Nitric Oxide/*metabolism ; Oxidation-Reduction ; RNA, Ribosomal, 16S/analysis ; Sequence Analysis, DNA ; }, abstract = {This work demonstrates bacterial oxidation of mercury (Hg[0]) coupled to nitric oxide (NO) reduction in a denitrifying membrane biofilm reactor (MBfR). In 93 days' operation, Hg[0] and NO removal efficiency attained 90.7% and 74.1%, respectively. Thauera, Pseudomonas, Paracoccus and Pannonibacter played dual roles as Hg[0] oxidizers and denitrifiers simultaneously. Denitrifying bacteria and the potential mercury resistant bacteria dominated the bacterial community. Denitrification-related genes (norB, norC, norD, norE, norQ and norV) and enzymatic Hg[0] oxidation-related genes (katG, katE) were responsible for bacterial oxidation of Hg[0] and NO reduction, as shown by metagenomic sequencing. XPS, HPLC-ICP-MS and SEM-EDS indicated the formation of a stable mercuric species (Hg[2+]) reasulting from Hg[0] oxidation in the biofilm. Bacterial oxidation of Hg[0] was coupled to NO reduction in which Hg[0] served as the initial electron donor while NO served as the terminal electron acceptor and thereby redox between Hg[0] and NO was formed. MBfR was capable of both Hg[0] bio-oxidation and denitrifying NO reduction. This research opens up new possibilities for application of MBfR to simultaneous flue gas demercuration and denitration.}, } @article {pmid30677984, year = {2019}, author = {Wu, Y and Wu, Z and Chu, H and Li, J and Ngo, HH and Guo, W and Zhang, N and Zhang, H}, title = {Comparison study on the performance of two different gas-permeable membranes used in a membrane-aerated biofilm reactor.}, journal = {The Science of the total environment}, volume = {658}, number = {}, pages = {1219-1227}, doi = {10.1016/j.scitotenv.2018.12.121}, pmid = {30677984}, issn = {1879-1026}, mesh = {*Biofilms ; *Biomass ; *Bioreactors ; Carbon/*analysis ; Hydrophobic and Hydrophilic Interactions ; Membranes, Artificial ; Nitrogen/*analysis ; Porosity ; Waste Disposal, Fluid ; }, abstract = {This study compared the performance of two different gas-permeable membranes, PVDF and PP membrane, in a membrane-aerated biofilm reactor (MABR). The surface characteristics and membrane pore blocking of these two membrane materials were studied utilizing AFM, SEM and CLSM. The PVDF membrane surface was more rough and hydrophilic, and possessed a better microbial affinity compared to PP. Furthermore, the MABR equipped with a PVDF membrane removed more COD (97.06 ± 0.97%) and TN (85.66 ± 0.87%) compared to the MABR with PP membrane (87.13 ± 0.87% and 71.13 ± 0.71%, respectively). As well, the PP membrane exhibited severe membrane pore blocking and had a lower oxygen transfer rate than the PVDF membrane. It is concluded that the PVDF membrane has potential as an aeration membrane material for MABRs.}, } @article {pmid30677974, year = {2019}, author = {Kurzbaum, E and Iliasafov, L and Kolik, L and Starosvetsky, J and Bilanovic, D and Butnariu, M and Armon, R}, title = {From the Titanic and other shipwrecks to biofilm prevention: The interesting role of polyphenol-protein complexes in biofilm inhibition.}, journal = {The Science of the total environment}, volume = {658}, number = {}, pages = {1098-1105}, doi = {10.1016/j.scitotenv.2018.12.197}, pmid = {30677974}, issn = {1879-1026}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; *Bacterial Adhesion ; *Bacterial Physiological Phenomena ; Biofilms/*drug effects ; Polyphenols/*pharmacology ; Proteins/*pharmacology ; }, abstract = {Bacteria attach themselves either reversibly or irreversibly onto practically any surface in aqueous and other environments in order to reproduce, while generating extracellular polymeric substances (EPS) as a supportive structure for biofilm formation. Surfaces with a potential to prevent cellular attachment and aggregation (biofilm) would be extremely useful in environmental, biotechnological, medical and industrial applications. The scientific community is currently focusing on the design of micro- and nano-scale textured surfaces with antibacterial and/or antifouling properties (e.g., filtration membranes). Several serum and tissue proteins promote bacterial adhesion (for example, albumin, fibronectin and fibrinogen), whereas polyphenols form complexes with proteins which change their structural, functional and nutritional properties. For example, tannic acid, a compound composed of polygalloyl glucoses or polygalloyl quinic acid esters and several galloyl moieties, inhibits the growth of many bacterial strains. The present review is based on different nautical archaeology research data, and asks a simple but as yet unanswered question: What is the chemistry that prevents leather biodegradation by environmental bacteria and/or formation of biofilms? Future research should answer these questions, which are highly important for biofilm prevention.}, } @article {pmid30675370, year = {2019}, author = {Kumar, A and Alam, A and Grover, S and Pandey, S and Tripathi, D and Kumari, M and Rani, M and Singh, A and Akhter, Y and Ehtesham, NZ and Hasnain, SE}, title = {Peptidyl-prolyl isomerase-B is involved in Mycobacterium tuberculosis biofilm formation and a generic target for drug repurposing-based intervention.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {3}, pmid = {30675370}, issn = {2055-5008}, mesh = {Acarbose/chemistry/*metabolism ; Antitubercular Agents/chemistry/*metabolism ; Biofilms/drug effects/*growth & development ; Cyclophilins/chemistry/*metabolism ; Cyclosporine/chemistry/*metabolism ; Drug Repositioning ; Gallium/metabolism ; Microbial Viability/drug effects ; Molecular Docking Simulation ; Mycobacterium smegmatis/drug effects/growth & development ; Mycobacterium tuberculosis/drug effects/*enzymology/*growth & development ; Protein Binding ; Surface Plasmon Resonance ; }, abstract = {Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M.tb), takes one human life every 15 s globally. Disease relapse occurs due to incomplete clearance of the pathogen and reactivation of the antibiotic tolerant bacilli. M.tb, like other bacterial pathogens, creates an ecosystem of biofilm formed by several proteins including the cyclophilins. We show that the M.tb cyclophilin peptidyl-prolyl isomerase (PpiB), an essential gene, is involved in biofilm formation and tolerance to anti-mycobacterial drugs. We predicted interaction between PpiB and US FDA approved drugs (cyclosporine-A and acarbose) by in-silico docking studies and this was confirmed by surface plasmon resonance (SPR) spectroscopy. While all these drugs inhibited growth of Mycobacterium smegmatis (M.smegmatis) when cultured in vitro, acarbose and cyclosporine-A showed bacteriostatic effect while gallium nanoparticle (GaNP) exhibited bactericidal effect. Cyclosporine-A and GaNP additionally disrupted M.tb H37Rv biofilm formation. Co-culturing M.tb in their presence resulted in significant (2-4 fold) decrease in dosage of anti-tubercular drugs- isoniazid and ethambutol. Comparison of the cyclosporine-A and acarbose binding sites in PpiB homologues of other biofilm forming infectious pathogens revealed that these have largely remained unaltered across bacterial species. Targeting bacterial biofilms could be a generic strategy for intervention against bacterial pathogens.}, } @article {pmid30674577, year = {2019}, author = {Obručová, H and Kotásková, I and Tihelková, R and Holá, V and Růžička, F and Freiberger, T}, title = {Fluorescent Capillary Electrophoresis Is Superior to Culture in Detecting Candida Species from Samples of Urinary Catheters and Ureteral Stents with Mono- or Polyfungal Biofilm Growth.}, journal = {Journal of clinical microbiology}, volume = {57}, number = {4}, pages = {}, pmid = {30674577}, issn = {1098-660X}, mesh = {Aged ; Biofilms/*growth & development ; Candida/classification/*isolation & purification ; Candida albicans/isolation & purification ; Candida parapsilosis/isolation & purification ; Candida tropicalis/isolation & purification ; Candidiasis/microbiology/urine ; Colony Count, Microbial/standards ; DNA, Fungal/genetics ; DNA, Ribosomal/genetics ; Electrophoresis, Capillary/*methods ; Female ; Fluorescence ; Humans ; Male ; Molecular Diagnostic Techniques/instrumentation/methods ; Sensitivity and Specificity ; Stents/*microbiology ; Urinary Catheters/*microbiology ; }, abstract = {Molecular techniques in fungal detection and identification represent an efficient complementary diagnostic tool which is increasingly used to overcome limitations of routinely used culture techniques. The aim of this study was to characterize Candida sp. representation in samples from urine, urinary catheter, and ureteral stent biofilm using ITS2 ribosomal DNA (rDNA) amplification followed by fluorescent capillary electrophoresis (f-ITS2-PCR-CE) and to compare the results with those obtained by culture. A total of 419 samples were analyzed, and 106 (25.2%) were found positive, out of which 17 (16%) were polyfungal. The positivity rate did not differ between samples from catheters and stents (23.6% versus 20.9%) or between catheter and stent corresponding urine samples (40.2% versus 30.2%). Ten different Candida species were detected, with Candida parapsilosis (31.4%), Candida albicans (26.5%), and Candida tropicalis (12.4%) predominating. f-ITS2-PCR-CE was evaluated as substantially less time-consuming and 8.3 times more sensitive than the routinely applied culture technique with 1 µl of urine/sonicated fluid inoculated, detecting 67 (19.9%) versus 8 (2.4%) positive samples out of 337 initially analyzed samples. The culture sensitivity considerably improved to 1.7 times lower than that of f-ITS2-PCR-CE after the inoculation volume was increased to 100 µl in the additional 82 samples. Moreover, the molecular technique, unlike routine cultivation, enabled precise pathogen composition determination in polymicrobial samples. In conclusion, the f-ITS2-PCR-CE method was shown to be a quick and efficient tool for culture-independent detection and identification of fungi in urinary tract-related samples, demonstrating a higher sensitivity than culture.}, } @article {pmid30672433, year = {2018}, author = {Hatami Moghadam, R and Alvandi, A and Akbari, N and Jafari, P and Abiri, R}, title = {Assessment of biofilm formation among clinical isolates of Acinetobacter baumannii in burn wounds in the west of Iran.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {64}, number = {15}, pages = {30-34}, pmid = {30672433}, issn = {1165-158X}, mesh = {Acinetobacter baumannii/drug effects/*isolation & purification/*physiology ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Burns/*microbiology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Iran ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Ozone/pharmacology ; Real-Time Polymerase Chain Reaction ; Wounds and Injuries/*microbiology ; Young Adult ; }, abstract = {Burn wound infection by A. baumannii is one of the predominant cause of mortality worldwide. The present investigation aimed at determination of antimicrobial resistance profile and expression of the biofilm-related genes in A. baumannii isolated from hospitalized patients with burn wound infection in Kermanshah hospitals. Sixty four isolates of A. baumannii were recovered from burn wound of hospitalized patients at hospitals in Kermanshah. The antimicrobial susceptibility testing (AST) was performed. Biofilm formation was measured and antibiotic resistance was compared between before and after of biofilm formation. The polymerase chain reaction (PCR) and Real-Time PCR were performed to detect of abaI and pgaD genes. The biofilm producer isolates and the most resistant isolates were exposed to ozone gas .More than 70% strains were resistance to Erythromycin, Ofloxacin, Ceftazidime, Ceftriaxone, and Ticarcillin-clavulanic acid and 50% isolates were resistant to Imipenem. Thirty one (48.4%) isolates were biofilm producer. The pgaD and abaI genes were positive in 29 (45.3%) and 9 (14%) isolates, respectively. Real time PCR demonstrated that the copy numbers of the pgaD and abaI genes after biofilm formation were increased. After exposure to ozone, biofilm formation reduced in all very strong biofilm producing isolates. Our results showed that after biofilm formation, an increased resistance was observed in most isolates. Also rising expression of abaI gene was associated with biofilm formation and an increase of antibiotic resistance. In the current study, both biofilm formation and antibiotic resistance were reduced after O3 exposure.}, } @article {pmid30671742, year = {2019}, author = {Jung, S and Park, OJ and Kim, AR and Ahn, KB and Lee, D and Kum, KY and Yun, CH and Han, SH}, title = {Lipoteichoic acids of lactobacilli inhibit Enterococcus faecalis biofilm formation and disrupt the preformed biofilm.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {57}, number = {4}, pages = {310-315}, pmid = {30671742}, issn = {1976-3794}, mesh = {Anti-Bacterial Agents/metabolism/*pharmacology ; Biofilms/*drug effects ; Dentin/microbiology ; Enterococcus faecalis/*drug effects/growth & development/physiology ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Lactobacillus/*chemistry/metabolism ; Lipopolysaccharides/metabolism/*pharmacology ; Microbial Sensitivity Tests ; Teichoic Acids/metabolism/*pharmacology ; Tooth Diseases/microbiology ; }, abstract = {Enterococcus faecalis, a Gram-positive bacterium commonly isolated in patients with refractory apical periodontitis, invades dentin tubules easily and forms biofilms. Bacteria in biofilms, which contribute to recurrent and/or chronic inflammatory diseases, are more resistant to antimicrobial agents than planktonic cells and easily avoid phagocytosis. Although Lactobacillus plantarum lipoteichoic acid (Lp.LTA) is associated with biofilm formation, the effect of Lp.LTA on biofilm formation by E. faecalis is not clearly understood. In this study, we investigated whether Lp.LTA inhibits E. faecalis biofilm formation. The degree of biofilm formation was determined by using crystal violet assay and LIVE/DEAD bacteria staining. The quantification of bacterial growth was determined by measuring the optical density at 600 nm with a spectrophotometer. Formation of biofilms on human dentin slices was observed under a scanning electron microscope. E. faecalis biofilm formation was reduced by Lp.LTA treatment in a dose-dependent manner. Lp.LTA inhibited biofilm development of E. faecalis at the early stage without affecting bacterial growth. LTA from other Lactobacillus species such as Lactobacillus acidophilus, Lactobacillus casei, or Lactobacillus rhamnosus GG also inhibited E. faecalis biofilm formation. In particular, among LTAs from various lactobacilli, Lp.LTA showed the highest inhibitory effect on biofilms formed by E. faecalis. Interestingly, LTAs from lactobacilli could remove the biofilm preformed by E. faecalis. These inhibitory effects were also observed on the surface of human dentin slices. In conclusion, Lactobacillus species LTA inhibits biofilm formation caused by E. faecalis and it could be used as an anti-biofilm agent for prevention or treatment against E. faecalis-associated diseases.}, } @article {pmid30670553, year = {2019}, author = {Yonemoto, K and Chiba, A and Sugimoto, S and Sato, C and Saito, M and Kinjo, Y and Marumo, K and Mizunoe, Y}, title = {Redundant and Distinct Roles of Secreted Protein Eap and Cell Wall-Anchored Protein SasG in Biofilm Formation and Pathogenicity of Staphylococcus aureus.}, journal = {Infection and immunity}, volume = {87}, number = {4}, pages = {}, pmid = {30670553}, issn = {1098-5522}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Bombyx/microbiology ; Cell Wall/genetics/*metabolism ; Gene Deletion ; Humans ; Larva/microbiology ; Membrane Proteins/genetics/*metabolism ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/genetics/*pathogenicity/*physiology ; Virulence ; }, abstract = {Chronic and fatal infections caused by Staphylococcus aureus are sometimes associated with biofilm formation. Secreted proteins and cell wall-anchored proteins (CWAPs) are important for the development of polysaccharide-independent biofilms, but functional relationships between these proteins are unclear. In the present study, we report the roles of the extracellular adherence protein Eap and the surface CWAP SasG in S. aureus MR23, a clinical methicillin-resistant isolate that forms a robust protein-dependent biofilm and accumulates a large amount of Eap in the extracellular matrix. Double deletion of eap and sasG, but not single eap or sasG deletion, reduced the biomass of the formed biofilm. Mutational analysis demonstrated that cell wall anchorage is essential for the role of SasG in biofilm formation. Confocal laser scanning microscopy revealed that MR23 formed a rugged and thick biofilm; deletion of both eap and sasG reduced biofilm ruggedness and thickness. Although sasG deletion did not affect either of these features, eap deletion reduced the ruggedness but not the thickness of the biofilm. This indicated that Eap contributes to the rough irregular surface structure of the MR23 biofilm and that both Eap and SasG play roles in biofilm thickness. The level of pathogenicity of the Δeap ΔsasG strain in a silkworm larval infection model was significantly lower (P < 0.05) than those of the wild type and single-deletion mutants. Collectively, these findings highlight the redundant and distinct roles of a secreted protein and a CWAP in biofilm formation and pathogenicity of S. aureus and may inform new strategies to control staphylococcal biofilm infections.}, } @article {pmid30668324, year = {2019}, author = {Aygül, A and Öztürk, İ and Çilli, FF and Ermertcan, Ş}, title = {Quercetin inhibits swarming motility and activates biofilm production of Proteus mirabilis possibly by interacting with central regulators, metabolic status or active pump proteins.}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {57}, number = {}, pages = {65-71}, doi = {10.1016/j.phymed.2018.12.014}, pmid = {30668324}, issn = {1618-095X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Proteus mirabilis/*drug effects/pathogenicity/physiology ; Quercetin/*pharmacology ; Virulence Factors/antagonists & inhibitors ; }, abstract = {BACKGROUND: Via its virulence factors such as swarm differentiation, biofilm and hemolysin production, urease enzyme, Proteus mirabilis causes urinary tract infections (UTIs), especially in complicated cases. Anti-pathogenic compounds attenuate the virulence of bacteria without showing 'cidal' activity and carry the potential to be used in the prevention and treatment of infectious diseases.

PURPOSE: Search for anti-pathogenic effects of quercetin, which is a widely known and biologically active phytochemical, on Proteus mirabilis was the purpose of this study. In this context, the potential inhibitory activity of quercetin on swarming motility and biofilm production of a wild-type strain, P. mirabilis HI4320, was investigated in both phenotypically and genotypically.

METHODS: Quercetin's effect on swarming motility was examined on LB agar plates, containing quercetin at various concentrations, by measuring the swarming diameter. The effect on biofilm formation, on the other hand, was analyzed by staining the formed biofilm of the bacterium, exposed to quercetin at various concentrations, with crystal violet and reading spectrophotometrically. Differences in expression levels of selected genes involved in swarming regulation were determined by real-time reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) to evaluate the mechanism of inhibitory action on swarming. Further investigations were carried out repeating swarming assays with the clones that derived from the wild-type strain by a TA system kit for direct one-step cloning and overexpressing the relevant genes.

RESULTS: Our study revealed that quercetin inhibited swarming motility while activating biofilm production of P. mirabilis in direct proportion to the dose. Although all selected genes are inhibited in the same manner in liquid medium, and no significant differences could be detected in solid medium as demonstrated by RT-qPCR, experiments repeated with the clones overexpressing flhC (a component of flagellar transcriptional activator), speB (an agmatinase enzyme) and ompF (an outer membrane porin) genes showed that the respective clones could restore swarming, compensating for the inhibitory effect of quercetin.

CONCLUSION: Quercetin's inhibitory effect on P. mirabilis swarming was possibly due to interactions with components of swarming regulators, the genes expressing polyamine coding enzymes that trigger swarm differentiation, or active pump proteins.}, } @article {pmid30667567, year = {2019}, author = {Saeed, K and McLaren, AC and Schwarz, EM and Antoci, V and Arnold, WV and Chen, AF and Clauss, M and Esteban, J and Gant, V and Hendershot, E and Hickok, N and Higuera, CA and Coraça-Huber, DC and Choe, H and Jennings, JA and Joshi, M and Li, WT and Noble, PC and Phillips, KS and Pottinger, PS and Restrepo, C and Rohde, H and Schaer, TP and Shen, H and Smeltzer, M and Stoodley, P and Webb, JCJ and Witsø, E}, title = {2018 international consensus meeting on musculoskeletal infection: Summary from the biofilm workgroup and consensus on biofilm related musculoskeletal infections.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {37}, number = {5}, pages = {1007-1017}, doi = {10.1002/jor.24229}, pmid = {30667567}, issn = {1554-527X}, mesh = {*Biofilms ; Humans ; Musculoskeletal Diseases/*microbiology ; Prosthesis-Related Infections/*microbiology ; }, abstract = {Biofilm-associated implant-related bone and joint infections are clinically important due to the extensive morbidity, cost of care and socioeconomic burden that they cause. Research in the field of biofilms has expanded in the past two decades, however, there is still an immense knowledge gap related to many clinical challenges of these biofilm-associated infections. This subject was assigned to the Biofilm Workgroup during the second International Consensus Meeting on Musculoskeletal Infection held in Philadelphia USA (ICM 2018) (https://icmphilly.com). The main objective of the Biofilm Workgroup was to prepare a consensus document based on a review of the literature, prepared responses, discussion, and vote on thirteen biofilm related questions. The Workgroup commenced discussing and refining responses prepared before the meeting on day one using Delphi methodology, followed by a tally of responses using an anonymized voting system on the second day of ICM 2018. The Working group derived consensus on information about biofilms deemed relevant to clinical practice, pertaining to: (1) surface modifications to prevent/inhibit biofilm formation; (2) therapies to prevent and treat biofilm infections; (3) polymicrobial biofilms; (4) diagnostics to detect active and dormant biofilm in patients; (5) methods to establish minimal biofilm eradication concentration for biofilm bacteria; and (6) novel anti-infectives that are effective against biofilm bacteria. It was also noted that biomedical research funding agencies and the pharmaceutical industry should recognize these areas as priorities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.}, } @article {pmid30667139, year = {2019}, author = {Yan, J and Moreau, A and Khodaparast, S and Perazzo, A and Feng, J and Fei, C and Mao, S and Mukherjee, S and Košmrlj, A and Wingreen, NS and Bassler, BL and Stone, HA}, title = {Bacterial Biofilm Material Properties Enable Removal and Transfer by Capillary Peeling.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {31}, number = {4}, pages = {e1807586}, doi = {10.1002/adma.201807586}, pmid = {30667139}, issn = {1521-4095}, } @article {pmid30665746, year = {2019}, author = {Cáceres, ME and Etcheverría, AI and Padola, NL}, title = {[Effects of the culture medium and the methodology applied on the biofilm formation of 2diarrheagenic Escherichia coli strains].}, journal = {Revista Argentina de microbiologia}, volume = {51}, number = {3}, pages = {208-213}, doi = {10.1016/j.ram.2018.04.007}, pmid = {30665746}, issn = {0325-7541}, mesh = {Bacteriological Techniques ; Biofilms/*drug effects/growth & development ; Culture Media/*pharmacology ; Enteropathogenic Escherichia coli/*drug effects/pathogenicity/physiology ; Glucose/pharmacology ; Polystyrenes ; Shiga-Toxigenic Escherichia coli/*drug effects/pathogenicity/physiology ; Species Specificity ; }, abstract = {The ability to form biofilms of pathogenic microorganisms in a wide variety of environments, surfaces and conditions constitute an important risk, both for the food industry and for public health. The aim of this work was to evaluate and to compare the effects of the methodology applied and the culture medium used on the ability of a non-O157 verotoxigenic Escherichia coli strain and an enteropathogenic strain to form biofilm on polystyrene surface. Two methodological variants were tested in static culture and culture mediums with different composition were used. The results showed that both strains were able to form a greater biofilm under culture in LB supplemented with glucose, with medium replacement at 24h and the quantification of the biofilm carried out at 48h of incubation. These conditions could be used in future studies on biofilm formation.}, } @article {pmid30664803, year = {2019}, author = {Levipan, HA and Irgang, R and Tapia-Cammas, D and Avendaño-Herrera, R}, title = {A high-throughput analysis of biofilm formation by the fish pathogen Tenacibaculum dicentrarchi.}, journal = {Journal of fish diseases}, volume = {42}, number = {4}, pages = {617-621}, doi = {10.1111/jfd.12949}, pmid = {30664803}, issn = {1365-2761}, support = {FONDAP 15110027//Comisión Nacional de Investigación Científica y Tecnológica/International ; FONDECYT 1190283//Comisión Nacional de Investigación Científica y Tecnológica/International ; FONDEQUIP EQM160131, UPLA//Comisión Nacional de Investigación Científica y Tecnológica/International ; PAI/Convocatoria Nacional Subvención a la Instala//Comisión Nacional de Investigación Científica y Tecnológica/International ; FONDECYT 1150695//Comisión Nacional de Investigación Científica y Tecnológica/International ; }, mesh = {Animals ; Automation/instrumentation ; Biofilms/*growth & development ; Fish Diseases/microbiology ; Fishes/*microbiology ; Flavobacteriaceae Infections/*veterinary ; High-Throughput Screening Assays/*methods ; Microbial Viability ; Microscopy/methods ; Tenacibaculum/*pathogenicity ; }, } @article {pmid30663958, year = {2019}, author = {Almblad, H and Rybtke, M and Hendiani, S and Andersen, JB and Givskov, M and Tolker-Nielsen, T}, title = {High levels of cAMP inhibit Pseudomonas aeruginosa biofilm formation through reduction of the c-di-GMP content.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {3}, pages = {324-333}, doi = {10.1099/mic.0.000772}, pmid = {30663958}, issn = {1465-2080}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic AMP/*metabolism ; Cyclic AMP Receptor Protein/genetics/metabolism ; Cyclic GMP/*analogs & derivatives/metabolism ; Extracellular Polymeric Substance Matrix/metabolism ; Mutation ; Phosphoric Diester Hydrolases/genetics/metabolism ; Pseudomonas aeruginosa/genetics/growth & development/metabolism/*physiology ; }, abstract = {The human pathogen Pseudomonas aeruginosa can cause both acute infections and chronic biofilm-based infections. Expression of acute virulence factors is positively regulated by cAMP, whereas biofilm formation is positively regulated by c-di-GMP. We provide evidence that increased levels of cAMP, caused by either a lack of degradation or increased production, inhibit P. aeruginosa biofilm formation. cAMP-mediated inhibition of P. aeruginosa biofilm formation required Vfr, and involved a reduction of the level of c-di-GMP, as well as reduced production of biofilm matrix components. A mutant screen and characterization of defined knockout mutants suggested that a subset of c-di-GMP-degrading phosphodiesterases is involved in cAMP-Vfr-mediated biofilm inhibition in P. aeruginosa.}, } @article {pmid30663885, year = {2018}, author = {Di Gregorio, L and Congestri, R and Tandoi, V and Neu, TR and Rossetti, S and Di Pippo, F}, title = {Biofilm diversity, structure and matrix seasonality in a full-scale cooling tower.}, journal = {Biofouling}, volume = {34}, number = {10}, pages = {1093-1109}, doi = {10.1080/08927014.2018.1541454}, pmid = {30663885}, issn = {1029-2454}, mesh = {Biodiversity ; Biofilms/*growth & development ; Chlorophyta/*growth & development ; Cold Temperature ; Cyanobacteria/*growth & development ; Diatoms/*growth & development ; In Situ Hybridization, Fluorescence ; Oil and Gas Industry ; Proteobacteria/*growth & development ; *Seasons ; Surface Properties ; }, abstract = {Biofilms commonly colonise cooling water systems, causing equipment damage and interference with the operational requirements of the systems. In this study, next-generation sequencing (NGS), catalysed reporter deposition fluorescence in situ hybridisation (CARD-FISH), lectin staining and microscopy were used to evaluate temporal dynamics in the diversity and structure of biofilms collected seasonally over one year from an open full-scale cooling tower. Water samples were analysed to evaluate the contribution of the suspended microorganisms to the biofilm composition and structure. Alphaproteobacteria dominated the biofilm communities along with Beta- and Gammaproteobacteria. The phototrophic components were mainly cyanobacteria, diatoms and green algae. Bacterial biodiversity decreased from winter to autumn, concurrently with an increase in cyanobacterial and microalgal richness. Differences in structure, spatial organisation and glycoconjugates were observed among assemblages during the year. Overall, microbial variation appeared to be mostly affected by irradiance and water temperature rather than the source of the communities. Variations in biofilms over seasons should be evaluated to develop specific control strategies.}, } @article {pmid30663552, year = {2018}, author = {Türkel, İ and Yıldırım, T and Yazgan, B and Bilgin, M and Başbulut, E}, title = {Relationship between antibiotic resistance, efflux pumps, and biofilm formation in extended-spectrum β-lactamase producing Klebsiella pneumoniae.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {30}, number = {6-8}, pages = {354-363}, doi = {10.1080/1120009X.2018.1521773}, pmid = {30663552}, issn = {1973-9478}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Down-Regulation/drug effects ; Drug Resistance, Microbial/*drug effects ; Genes, Bacterial/genetics ; Klebsiella pneumoniae/*drug effects/genetics/*metabolism ; Microbial Sensitivity Tests/methods ; Up-Regulation/drug effects ; beta-Lactamases/genetics/*metabolism ; }, abstract = {Klebsiella pneumoniae is an important pathogen both in community and hospital environment. In this study, we aimed to determine the antibiotic susceptibilities, expression levels of AcrA, ketM, kdeA, kpnEF, and kexD genes related to efflux pump and biofilm formation in 100 extended-spectrum β-lactamase producing Klebsiella pneumoniae. The relative expression levels of AcrA, ketM, kdeA, kpnEF, and kexD were determined by quantitative real-time PCR and biofilm formation was screened by microtiter plate assay. Based on CLSI breakpoints, zone diameters showed that 72% of isolates were resistant to ceftazidime, 79% to aztreonam, 54% to ciprofloxacin, 32% to ertapenem, 74% to tobramycin, 65% to tetracycline and all isolates were resistant to ampicillin, ceftriaxone, and cefotaxime. The relative expression of AcrA was upregulated in ciprofloxacin susceptible isolates and also upregulation of newly described efflux pump, kexD, was correlated with tobramycin and aztreonam resistance. A significant correlation was observed between resistance-nodulation-division and single-type efflux pumps. On the other hand, ciprofloxacin susceptible isolates formed stronger biofilms than resistant isolates. The up or down regulation of efflux pumps didn't enhance biofilm formation capacity.}, } @article {pmid30661470, year = {2019}, author = {Herrera, KMS and Silva, FKD and Oliveira, ME and Paiva, MC and Soares, AC and Siqueira Ferreira, JM}, title = {First report of polymyxin B activity in Klebsiella pneumoniae biofilm.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {31}, number = {3}, pages = {127-131}, doi = {10.1080/1120009X.2018.1558751}, pmid = {30661470}, issn = {1973-9478}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Humans ; Klebsiella Infections/*drug therapy/microbiology ; Klebsiella pneumoniae/*drug effects/physiology ; Microbial Sensitivity Tests ; Polymyxin B/*pharmacology ; Urine/*microbiology ; }, abstract = {Considering the clinical importance of biofilm in medical devices and chronic infections, this study aimed to investigate the action of polymyxin B on Klebsiella pneumoniae (K. pneumoniae) biofilm. The experiments were performed using a biofilm formation assay and the interaction of polysorbate 80 was explored. Both inhibition of biofilm formation and reduction of pre-formed biofilm occurred in a concentration-dependent manner with inhibition as high as 56 and 64%, and reduction of pre-formed biofilm as high as 70 and 66%, with and without polysorbate, respectively. The addition of polysorbate enhances the biofilm reduction, but more studies are needed to elucidate this mechanism. Our findings reveal, for the first time, polymyxin B as a potential agent for the treatment of K. pneumoniae biofilm, a current challenge for clinical practice.}, } @article {pmid30661345, year = {2018}, author = {Ham, Y and Kim, TJ}, title = {Nitrogen Sources Inhibit Biofilm Formation by Xanthomonas oryzae pv. oryzae.}, journal = {Journal of microbiology and biotechnology}, volume = {28}, number = {12}, pages = {2071-2078}, doi = {10.4014/jmb.1807.08025}, pmid = {30661345}, issn = {1738-8872}, mesh = {Amino Acids/metabolism ; Biofilms/*drug effects/growth & development ; Carbon/metabolism ; Cell Cycle ; Culture Media/chemistry ; Host-Pathogen Interactions/physiology ; Nitrates/metabolism ; Nitrogen/*metabolism/*pharmacology ; Nutrients ; Oryza/microbiology ; Phloem/microbiology ; Plant Diseases/microbiology ; Xanthomonas/*drug effects/growth & development/pathogenicity ; Xylem/microbiology ; }, abstract = {Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, which results in severe economic damage to rice farms. Xoo produces biofilms for pathogenesis and survival both inside and outside the host. Biofilms, which are important virulence factors, play a key role in causing the symptoms of Xoo infection. In the present study, we investigated the nutritional conditions for biofilm formation by Xoo. Although Xoo biofilm formation may be initiated by interactions with the host, Xoo biofilm cannot mature without the support of favorable nutritional conditions. Nitrogen sources inhibited Xoo biofilm formation by overwhelming the positive effect that cell growth has on it. However, limited nutrients with low amino acid concentration supported biofilm formation by Xoo in the xylem sap rather than in the phloem sap of rice.}, } @article {pmid30661218, year = {2019}, author = {Boháčová, M and Pazlarová, J and Fuchsová, V and Švehláková, T and Demnerová, K}, title = {Quantitative evaluation of biofilm extracellular DNA by fluorescence-based techniques.}, journal = {Folia microbiologica}, volume = {64}, number = {4}, pages = {567-577}, doi = {10.1007/s12223-019-00681-8}, pmid = {30661218}, issn = {1874-9356}, support = {MSMT No 20-SVV/2016//Ministerstvo ?kolstv?, Ml?de?e a T?lov?chovy/ ; GA?R 17-15936S//Grantov? Agentura ?esk? Republiky/ ; }, mesh = {*Biofilms ; Biological Transport ; DNA, Bacterial/chemistry/genetics/metabolism ; Extracellular Space/*microbiology ; Humans ; Listeria monocytogenes/chemistry/*genetics/physiology ; Listeriosis/*microbiology ; Microscopy, Confocal ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/chemistry/*genetics/physiology ; }, abstract = {The formation of a hardly removable biofilm in food processing and clinical settings calls for a deeper understanding of composition of the matrix that protects the biofilm cells, as the crucial matrix component is extracellular DNA (eDNA), participating in adhesion, aggregation and penetration reduction, yet serving as a horizontal gene transfer reservoir. Therefore, we evaluated eDNA release from the biofilm of two pathogens, Listeria monocytogenes and Staphylococcus aureus, with respect to their origin under different culturing condition. Primarily, the biofilms were observed by confocal laser scanning microscopy (CLSM) under conditions mimicking the food processing environment and human body. The eDNA was quantitatively characterised based on its area by IMARIS. Next, the eDNA content and biofilm formation were quantified by spectrophotometry. Data from both sets of experiments were statistically evaluated. The eDNA release varied between the microorganism, culturing conditions and the origin of strains. Independent of the method used, the clinical strains of S. aureus released more eDNA than the food related strains at 37 °C. eDNA content can be crucial discriminating matrix component between food related and clinical strains. Deeper understanding of the eDNA role in such a phenomenon could facilitate the design of effective strategy for biofilm disruption.}, } @article {pmid30660977, year = {2019}, author = {Shao, S and Hu, Y and Cheng, J and Chen, Y}, title = {Action of oxytetracycline (OTC) degrading bacterium and its application in Moving Bed Biofilm Reactor (MBBR) for aquaculture wastewater pre-treatment.}, journal = {Ecotoxicology and environmental safety}, volume = {171}, number = {}, pages = {833-842}, doi = {10.1016/j.ecoenv.2019.01.040}, pmid = {30660977}, issn = {1090-2414}, mesh = {Ammonia/metabolism ; Anti-Bacterial Agents/*metabolism ; *Aquaculture ; Biodegradation, Environmental ; Biofilms ; Bioreactors/*microbiology ; Nitrates/metabolism ; Ochrobactrum/*metabolism ; Oxytetracycline/*metabolism ; Waste Disposal, Fluid ; Wastewater/*chemistry ; Water Pollutants, Chemical/*metabolism ; }, abstract = {In this study, the characteristics of biodegradation of oxytetracycline (OTC) by strain Ochrobactrum sp. KSS10 were studied under various environmental conditions, including initial OTC concentrations, variable temperature, initial pH, and diverse carbon sources. The capability of this bacterial strain for performing simultaneous OTC degradation and nitrate reduction was also explored under aerobic conditions. An OTC degradation ratio of 63.33% and a nitrate removal ratio of 98.64% were obtained within 96 h. In addition, removal of OTC and ammonia from synthetic aquaculture wastewater by a Moving Bed Biofilm Reactor (MBBR) and changes in the resistant genes of microbial communities were also investigated. The results demonstrated that the strain KSS10 was the dominant contributor in OTC and ammonia removal in the MBBR chamber. It removed almost all ammonia and approximately 76.42% of OTC. The abundances of genes tetL, tetX and intI1 were reduced by the MBBR, but the abundance of tetG and tetM were increased due to horizontal and vertical gene transfers. Such a result can potentially be used by the strain KSS10 for removing antibiotics and nitrogen from aquaculture wastewater during pre-treatment.}, } @article {pmid30660829, year = {2019}, author = {Pandolfi, F and D'Acierno, F and Bortolami, M and De Vita, D and Gallo, F and De Meo, A and Di Santo, R and Costi, R and Simonetti, G and Scipione, L}, title = {Searching for new agents active against Candida albicans biofilm: A series of indole derivatives, design, synthesis and biological evaluation.}, journal = {European journal of medicinal chemistry}, volume = {165}, number = {}, pages = {93-106}, doi = {10.1016/j.ejmech.2019.01.012}, pmid = {30660829}, issn = {1768-3254}, mesh = {Animals ; Antifungal Agents/*chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Drug Design ; Humans ; Indoles/chemical synthesis/chemistry/*pharmacology ; Moths/drug effects ; Structure-Activity Relationship ; }, abstract = {Candida albicans biofilm represents a major clinical problem due to its intrinsic tolerance to anti-fungal compounds and it has been highly related to infections in catheterized patients. Few compounds are described as able to inhibit biofilm formation or to interfere with preformed biofilm of C. albicans. Here we report the in vitro evaluation of anti-biofilm activity on C. albicans ATCC 10231 of a series of new and already known amine and amide indole derivatives. Among the studied compounds, fifteen resulted active on C. albicans ATCC 10231 biofilm, with BMIC50 ≤ 16 μg/mL. Three of them (7, 23 and 33) showed a selectivity towards mature biofilm and the most active of them was the compound 23 (BMIC50 = 4 μg/mL). On the other hands, two different compounds (21 and 22) were selective towards biofilm formation with BMIC50 values of 8 μg/mL. Otherwise, compounds 16 and 17 resulted active on biofilm formation, with BMIC50 of 8 μg/mL and 2 μg/mL respectively, and on mature biofilm with BMIC50 of 2 μg/mL. These two last compounds also showed an interesting activity towards the planktonic cells of C. albicans. A selection of the more active compounds was also evaluated on different C. albicans strains (PMC1042, PMC1083 and ATCC 10261), showing a comparable or higher anti-biofilm activity, especially on mature biofilm. In vivo toxicity studies using the Galleria mellonella larvae, were finally carried out on more active indole derivatives, showing that they are poorly toxic even at the highest concentrations tested (500-1000 μg/mL).}, } @article {pmid30659765, year = {2019}, author = {Yang, Y and Mao, M and Lei, L and Li, M and Yin, J and Ma, X and Tao, X and Yang, Y and Hu, T}, title = {Regulation of water-soluble glucan synthesis by the Streptococcus mutans dexA gene effects biofilm aggregation and cariogenic pathogenicity.}, journal = {Molecular oral microbiology}, volume = {34}, number = {2}, pages = {51-63}, doi = {10.1111/omi.12253}, pmid = {30659765}, issn = {2041-1014}, mesh = {Animals ; Biofilms/*growth & development ; Dental Caries ; Dextranase/*genetics ; Female ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Glucans/*biosynthesis/chemistry ; Glucose/metabolism ; Glucosyltransferases/genetics ; Humans ; Hydrogen-Ion Concentration ; Male ; Mannose/metabolism ; Models, Animal ; Mutation ; Phenotype ; Rats ; Rats, Sprague-Dawley ; Streptococcus mutans/*enzymology/*genetics/growth & development/*metabolism ; Transcriptome ; Virulence ; Water/*chemistry ; }, abstract = {The cariogenic pathogen Streptococcus mutans effectively utilizes dietary sucrose for the synthesis of exopolysaccharides (EPS), which act as a scaffold for its biofilm and thus contribute to its cariogenic pathogenicity. Dextranase (Dex), which is a type of glucanase, participates in the degradation of water-soluble glucan (WSG); however, the structural features of the EPS regulated by the dexAgene have received limited attention. Our recent studies reported novel protocols to fractionate and analyzed the structural characteristics of glucans from S mutans biofilms. In this study, we identify the role of the S mutans dexAgene in dextran-dependent aggregation in biofilm formation. Our results show that deletion of dexA (SmudexA) results in increased transcription of EPS synthesis-related genes, including gtfB, gtfD, and ftf. Interestingly, we reveal that inactivating the dexA gene may lead to elevated WSG synthesis in S mutans , which results in dysregulated cariogenicity in vivo. Furthermore, structural analysis provides new insights regarding the lack of mannose monosaccharides, especially in the WSG synthesis of the SmudexA mutants. The biofilm phenotypes that are associated with the reduced glucose monosaccharide composition in both WSG and water-insoluble glucan shift the dental biofilm to reduce the cariogenic incidence of the SmudexA mutants. Taken together, these data reveal that EPS synthesis fine-tuning by the dexA gene results in a densely packed EPS matrix that may impede the glucose metabolism of WSG, thereby leading to the lack of an energy source for the bacteria. These results highlight dexA targeting as a potentially effective tool in dental caries management.}, } @article {pmid30659724, year = {2019}, author = {Turgay, E and Steinum, TM and Colquhoun, D and Karataş, S}, title = {Environmental biofilm communities associated with early-stage common dentex (Dentex dentex) culture.}, journal = {Journal of applied microbiology}, volume = {126}, number = {4}, pages = {1032-1043}, doi = {10.1111/jam.14205}, pmid = {30659724}, issn = {1365-2672}, support = {20950//Scientific Research Project Coordination Unit of Istanbul University/ ; }, mesh = {Animal Feed/analysis ; Animals ; Bacteria/classification/genetics/isolation & purification ; Biofilms/classification/*growth & development ; *Life Cycle Stages ; Metagenomics ; Microbiota/*genetics ; Perciformes/*growth & development/*microbiology ; RNA, Ribosomal, 16S/genetics ; }, abstract = {AIMS: To describe the biofilm microbiota associated with various feeding phases during larval common dentex (Dentex dentex) culture.

METHODS AND RESULTS: A targeted metagenomic (metagenetic) study was performed by means of 16S rRNA gene-based PCR and NextGen pyrosequencing. The resulting dataset was scrutinized with microbial community analysis software (r packages) using r/Rstudio. While median observed and estimated alpha-diversities were 171 ± 38 and 207 ± 27 taxa, respectively, 72·1-85·8% of individual biofilm communities comprised only 27-46 taxa. Members of the genus Methylobacterium and family Rhodobacteraceae dominated biofilms formed during all feeding phases while genera Nannochloropsis and Tetraselmis microalgae were major constituents of biofilms during rotifer live feeding. Both potential fish pathogenic genera, for example, Vibrio and putatively probiotic taxa, for example, Phaeobacter gallaeciensis were identified.

CONCLUSIONS: Relatively stable biofilm communities were identified during each feeding phase but varied significantly between feeding phases, most likely in response to the introduction of live feed/microalgae-associated bacteria into rearing tanks.

The structure of the bacterial communities identified represents a 'template' for successful larval dentex culture and provides a foundation for future investigations into failed production cycles.}, } @article {pmid30659584, year = {2019}, author = {Li, DB and Li, J and Liu, DF and Ma, X and Cheng, L and Li, WW and Qian, C and Mu, Y and Yu, HQ}, title = {Potential regulates metabolism and extracellular respiration of electroactive Geobacter biofilm.}, journal = {Biotechnology and bioengineering}, volume = {116}, number = {5}, pages = {961-971}, doi = {10.1002/bit.26928}, pmid = {30659584}, issn = {1097-0290}, mesh = {Biofilms/*growth & development ; Geobacter/*physiology ; Membrane Potentials/*physiology ; }, abstract = {Dissimilatory metal reducer Geobacter sulfurreducens can mediate redox processes through extracellular electron transfer and exhibit potential-dependent electrochemical activity in biofilm. Understanding the microbial acclimation to potential is of critical importance for developing robust electrochemically active biofilms and facilitating their environmental, geochemical, and energy applications. In this study, the metabolism and redox conduction behaviors of G. sulfurreducens biofilms developed at different potentials were explored. We found that electrochemical acclimation occurred at the initial hours of polarizing G. sulfurreducens cells to the potentials. Two mechanisms of acclimation were found, depending on the polarizing potential. In the mature biofilms, a low level of biosynthesis and a high level of catabolism were maintained at +0.2 V versus standard hydrogen electrode (SHE). The opposite results were observed at potentials higher than or equal to +0.4 V versus SHE. The potential also regulated the constitution of the electron transfer network by synthesizing more extracellular cytochrome c such as OmcS at 0.0 and +0.2 V and exhibited a better conductivity. These findings provide reasonable explanations for the mechanism governing the electrochemical respiration and activity in G. sulfurreducens biofilms.}, } @article {pmid30658694, year = {2019}, author = {Dumaru, R and Baral, R and Shrestha, LB}, title = {Study of biofilm formation and antibiotic resistance pattern of gram-negative Bacilli among the clinical isolates at BPKIHS, Dharan.}, journal = {BMC research notes}, volume = {12}, number = {1}, pages = {38}, pmid = {30658694}, issn = {1756-0500}, mesh = {Acinetobacter/drug effects/metabolism/physiology ; Anti-Bacterial Agents ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Drug Resistance, Microbial/*drug effects ; Escherichia coli/drug effects/metabolism/physiology ; Gram-Negative Bacteria/classification/*drug effects/physiology ; Gram-Negative Bacterial Infections/*drug therapy/metabolism/microbiology ; Humans ; Microbial Sensitivity Tests ; Nepal ; beta-Lactamases/metabolism ; }, abstract = {OBJECTIVES: Gram-negative bacilli are the common causative agents for community-acquired, nosocomial and opportunistic infections. The recent upsurge of biofilm, as well as beta-lactamases producing strains, have synergistically led to the extensive dissemination of multi-drug resistant gram-negative bacilli. This study was carried out with an intention to detect the biofilm formation by gram-negative bacilli and determine their antibiogram along with the detection of extended-spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) production.

RESULTS: Among 314 isolates, Escherichia coli (38%) were the predominant isolates followed by Acinetobacter spp. (20%), Klebsiella spp. (16%), and Pseudomonas spp. (12%). Overall, 197 (62.73%) of isolates were biofilm positive. 84 (26.75%) and 51 (16.24%) were confirmed as ESBL and MBL producers respectively. The association between MBL production and biofilm formation was statistically significant (χ[2] = 10.20, P value= 0.002) whereas it was insignificant between ESBL and biofilm production (χ[2] = 0.006, P-value= 0.937). Most of the biofilm and MBL producing strains were multi-drug resistant.}, } @article {pmid30658415, year = {2019}, author = {Espinosa-Valdés, MP and Borbolla-Alvarez, S and Delgado-Espinosa, AE and Sánchez-Tejeda, JF and Cerón-Nava, A and Quintana-Romero, OJ and Ariza-Castolo, A and García-Del Río, DF and Loza-Mejía, MA}, title = {Synthesis, In Silico, and In Vitro Evaluation of Long Chain Alkyl Amides from 2-Amino-4-Quinolone Derivatives as Biofilm Inhibitors.}, journal = {Molecules (Basel, Switzerland)}, volume = {24}, number = {2}, pages = {}, pmid = {30658415}, issn = {1420-3049}, support = {SAL-05/11//Universidad La Salle/ ; }, mesh = {4-Quinolones/*chemistry ; Amides/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Catalytic Domain ; *Computer Simulation ; Ligands ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Proton Magnetic Resonance Spectroscopy ; Pseudomonas aeruginosa/drug effects/physiology ; Quorum Sensing/drug effects ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Infection from multidrug resistant bacteria has become a growing health concern worldwide, increasing the need for developing new antibacterial agents. Among the strategies that have been studied, biofilm inhibitors have acquired relevance as a potential source of drugs that could act as a complement for current and new antibacterial therapies. Based on the structure of 2-alkyl-3-hydroxy-4-quinolone and N-acylhomoserine lactone, molecules that act as mediators of quorum sensing and biofilm formation in Pseudomonas aeruginosa, we designed, prepared, and evaluated the biofilm inhibition properties of long chain amide derivatives of 2-amino-4-quinolone in Staphylococcus aureus and P. aeruginosa. All compounds had higher biofilm inhibition activity in P. aeruginosa than in S. aureus. Particularly, compounds with an alkyl chain of 12 carbons exhibited the highest inhibition of biofilm formation. Docking scores and molecular dynamics simulations of the complexes of the tested compounds within the active sites of proteins related to quorum sensing had good correlation with the experimental results, suggesting the diminution of biofilm formation induced by these compounds could be related to the inhibition of these proteins.}, } @article {pmid30657613, year = {2019}, author = {Kjaersgaard Andersen, R and Ring, HC and Kallenbach, K and Eriksen, JO and Jemec, GBE}, title = {Bacterial biofilm is associated with higher levels of regulatory T cells in unaffected hidradenitis suppurativa skin.}, journal = {Experimental dermatology}, volume = {28}, number = {3}, pages = {312-316}, doi = {10.1111/exd.13885}, pmid = {30657613}, issn = {1600-0625}, mesh = {Bacteria/*metabolism ; *Biofilms ; Biopsy ; CD4-Positive T-Lymphocytes/cytology ; CD8-Positive T-Lymphocytes/cytology ; Case-Control Studies ; Forkhead Transcription Factors/metabolism ; Hair Follicle/pathology ; Hidradenitis Suppurativa/*immunology/microbiology ; Humans ; Interleukin-17/metabolism ; Interleukin-1beta/metabolism ; Interleukin-2 Receptor alpha Subunit/metabolism ; Skin/*immunology/microbiology ; T-Lymphocytes, Regulatory/*immunology/microbiology ; }, abstract = {BACKGROUND: The role of bacterial biofilm in hidradenitis suppurativa (HS) is highly debated. Less biofilm is found in clinically unaffected axillary perilesional skin of HS patients compared with healthy controls.

OBJECTIVE: To study the correlation between biofilm and the phenotypical characterization of the preclinical inflammatory infiltrate.

MATERIALS AND METHODS: An exploratory comparative study of punch biopsies from unaffected axillary HS skin compared to similarly biopsies from healthy controls underwent standard staining procedures for CD4, CD8, CD25, FoxP3 and IL17. Standard-sized inflammatory histological hotspots were identified manually. Slides were scanned into Leica Biosystems' Digital Image Hub. Number of stained cells per slide and hotspot was found using an algorithm.

RESULTS: 12.5% of HS had biofilm compared to 85% of controls. For full slides, HS patients had more CD4+ cells than controls; HS patients with biofilm had higher CD4+ cell number than controls with or without biofilm and HS patients without biofilm. For hotspots, HS patients with biofilm had higher number of CD4+FoxP3+ cells than HS patients without biofilm and controls with biofilm.

CONCLUSION: The association between biofilm and the number of regulatory T cells in HS patients supports the concept of dysbiosis as a factor in the preclinical HS lesions.}, } @article {pmid30656428, year = {2019}, author = {Shelud'ko, AV and Filip'echeva, YA and Telesheva, EM and Yevstigneeva, SS and Petrova, LP and Katsy, EI}, title = {Polar flagellum of the alphaproteobacterium Azospirillum brasilense Sp245 plays a role in biofilm biomass accumulation and in biofilm maintenance under stationary and dynamic conditions.}, journal = {World journal of microbiology & biotechnology}, volume = {35}, number = {2}, pages = {19}, pmid = {30656428}, issn = {1573-0972}, mesh = {Azospirillum brasilense/genetics/*growth & development/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Culture Media/chemistry ; Flagella/*genetics/metabolism ; Hydrodynamics ; Mutation ; }, abstract = {Bacteria Azospirillum brasilense may swim and swarm owing to the rotation of a constitutive polar flagellum (Fla) and inducible lateral flagella (Laf). They also construct sessile biofilms on various interfaces. As compared to the wild-type strain Sp245, the previously characterized Fla[-] Laf[-] flhB1 mutant Sp245.1063 accumulated less biomass in mature biofilms, which also were susceptible to the forces of hydrodynamic shear. In this study, we compared biofilms formed by strain Sp245 and its previously constructed derivatives on the interfaces between a minimal (malate-salt medium, or MSM) or rich (LB) liquid growth medium and a hydrophilic (glass) or hydrophobic (polystyrene) solid surface under static or dynamic conditions. In all experimental settings, the alterations in Sp245.1063's mature biofilm traits were partially (in MSM) or completely (in LB) rescued in the complemented mutant Sp245.1063 (pRK415-150177), which received the pRK415-borne coding sequence for the putative FlhB1 protein of the flagellar type III secretion system. Although Laf were not found in the biofilms of azospirilla, Fla was present on the biofilm cells of the complemented mutant Sp245.1063 (pRK415-150177) and other studied strains, which had normal flagellation on liquid and solid nutritional media. Accordingly, mature biofilms of these strains contained more biomass and were significantly more resistant to shaking at 140 rpm, as compared to the biofilms of the flagella-free mutant bacteria. These data proved that the polar flagellum of A. brasilense Sp245 plays a significant positive role in biofilm biomass increase and in biofilm stabilization.}, } @article {pmid30656423, year = {2019}, author = {Unsal, T and Cansever, N and Ilhan-Sungur, E}, title = {Impact of biofilm in the maturation process on the corrosion behavior of galvanized steel: long-term evaluation by EIS.}, journal = {World journal of microbiology & biotechnology}, volume = {35}, number = {2}, pages = {22}, pmid = {30656423}, issn = {1573-0972}, support = {216Z133//Türkiye Bilimsel ve Teknolojik Araştirma Kurumu/ ; 33755//Bilimsel Araştirma Projeleri Birimi, Istanbul Üniversitesi/ ; 28949//Bilimsel Araştirma Projeleri Birimi, Istanbul Üniversitesi/ ; BEK-2016-21932//Bilimsel Araştirma Projeleri Birimi, Istanbul Üniversitesi/ ; FHZ-2016-21738//Bilimsel Araştirma Projeleri Birimi, Istanbul Üniversitesi/ ; BYP-2016-22742//Bilimsel Araştirma Projeleri Birimi, Istanbul Üniversitesi/ ; }, mesh = {Biofilms/*growth & development ; Corrosion ; Dielectric Spectroscopy ; Microscopy, Electron, Scanning ; Spectrometry, X-Ray Emission ; Steel/*chemistry ; Surface Properties ; Water Microbiology ; }, abstract = {In this study, the effect of biofilm in the maturation process on the corrosion behavior of galvanized steel was investigated in a model of a recirculating water system over 6 months. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods were used to determine the corrosion behavior of galvanized steel. The biofilm and corrosion products on the galvanized steel surfaces were investigated by using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). EIS results showed that the structure of the biofilm changed during the maturation process over time and the altering structure of the biofilm affects the corrosion behavior of galvanized steel. Also, EIS analyses validated that the biofilm has a dynamic and complex structure. The data obtained from SEM and macroscopic images indicated that EIS is an effective method for monitoring the biofilm-development process.}, } @article {pmid30654441, year = {2019}, author = {Hadjiargyrou, M and Donnenfeld, ED and Grillo, LM and Perry, HD}, title = {Differential Bacterial Colonization and Biofilm Formation on Punctal Occluders.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {2}, pages = {}, pmid = {30654441}, issn = {1996-1944}, abstract = {Dry eye is a common condition that is treated primarily by topical lubricants, immunomodulation, and a variety of punctal and canalicular plugs (occluders). Biofilm formation has been reported as an ongoing problem with the clinical use of occluders. In order to explore the role of biofilm formation on occluders, we tested the bacteria strain, Staphylococcus aureus, with three different types of occluders, Delta[R], Odyssey[R], and Alphamed[R]. Scanning electron microscopy (SEM) of these occluders revealed a variation in surface appearance, with Odyssey[R] being the smoothest (but with grooves), followed by Delta[R], and Alphamed[R]. Exposing each type of occluder to dynamically grown bacterial cultures of S. aureus, a ~3 fold statistically significant difference in bacteria colonization between the Odyssey[R] and Alphamed[R] occluder and a ~2 fold higher trend between Odyssey[R] and Delta[R] were detected. These quantitative results were also verified with SEM, showing extensive S. aureus colonization and biofilm formation on the surface of the Odyssey[R] occluder. The results also indicate that bacterial colonization readily occurs on all three types of occluders. The occluder with the smoothest but grooved surface (Odyssey[R]), displayed increased biofilm formation when compared to those with rougher surfaces.}, } @article {pmid30654101, year = {2019}, author = {Kannappan, A and Balasubramaniam, B and Ranjitha, R and Srinivasan, R and Packiavathy, IASV and Balamurugan, K and Pandian, SK and Ravi, AV}, title = {In vitro and in vivo biofilm inhibitory efficacy of geraniol-cefotaxime combination against Staphylococcus spp.}, journal = {Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association}, volume = {125}, number = {}, pages = {322-332}, doi = {10.1016/j.fct.2019.01.008}, pmid = {30654101}, issn = {1873-6351}, mesh = {Acyclic Monoterpenes ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans ; Cefotaxime/*pharmacology ; Down-Regulation/drug effects ; Drug Combinations ; Extracellular Polymeric Substance Matrix/drug effects ; Genes, Bacterial/genetics ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Staphylococcus epidermidis/*drug effects/genetics ; Terpenes/*pharmacology ; Xanthophylls/antagonists & inhibitors ; }, abstract = {In humans, the occurrence of bacterial communities in the form of biofilm is considered as a major intrinsic factor accountable for a variety of stubborn infections. Staphylococcus aureus and S. epidermidis have gained considerable attention in clinical settings owing to the formation of intractable and long-lasting biofilms in medical device. The current study has been designed to explain the biofilm inhibitory efficacy of geraniol and cefotaxime combination (GCC) against S. epidermidis and methicillin-resistant S. aureus (MRSA). Biofilm biomass quantification assay was performed to evaluate the antibiofilm activity of GCC against S. epidermidis and MRSA. The minimal biofilm inhibitory concentration of GCC was found to be 100 μg/ml of geraniol and 2 μg/ml of cefotaxime. Further, microscopic analyses ascertained the devastating potential of GCC on the test pathogens' biofilm formation. Besides biofilm inhibition, GCC also suppressed the production of extracellular polymeric substance, slime and staphyloxanthin. More, GCC significantly increased the susceptibility of the test pathogens towards human blood. Further, the results of real time PCR analysis and in vivo assay using Caenorhabditis elegans unveiled the anti-biofilm potentials of GCC. Thus, the present study demonstrates the significant use of polytherapy treatment approaches to overcome the biofilm associated infections of Staphylococcus spp.}, } @article {pmid30652791, year = {2019}, author = {Herek, TC and Menegazzo, VR and Ogaki, MB and Perini, HF and Maia, LF and Furlaneto, MC}, title = {Biofilm formation by blood isolates of Candida parapsilosis sensu stricto in the presence of a hyperglycidic solution at comparable concentrations of total parenteral nutrition.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {52}, number = {}, pages = {e20180182}, doi = {10.1590/0037-8682-0182-2018}, pmid = {30652791}, issn = {1678-9849}, mesh = {Biofilms/drug effects/*growth & development ; Candida parapsilosis/*physiology ; Colony Count, Microbial ; Culture Media/chemistry ; Glucose/*pharmacology ; Humans ; Parenteral Nutrition, Total ; }, abstract = {INTRODUCTION: Administration of total parenteral nutrition (TPN) via catheters increases the risk for candidemia from Candida parapsilosis.

METHODS: C. parapsilosis sensu stricto blood isolates were evaluated for ability total biomass biofilm formation and morphogenesis in presence of glucose at TPN equivalent concentrations.

RESULTS: Biofilms were increased at high glucose concentrations (25-30%) compared to the control medium. Significant increase in filamentous forms was observed in cultures with 30% glucose.

CONCLUSIONS: Biofilm formation by C. parapsilosis sensu stricto in hyperglycidic medium may contribute to its pathogenic potential for fungemia related to TPN catheters.}, } @article {pmid30652116, year = {2019}, author = {Coulter, J and Jakubovics, NS and Preshaw, PM and German, MJ}, title = {An in vitro model to assess effects of a desensitising agent on bacterial biofilm formation.}, journal = {Acta biomaterialia odontologica Scandinavica}, volume = {5}, number = {1}, pages = {1-8}, pmid = {30652116}, issn = {2333-7931}, abstract = {Desensitising agents are added to dentifrices to occlude exposed dentine tubules and reduce pain associated with dentine hypersensitivity. In occluding the tubules these agents may alter the surface layer of the dentine and consequently affect bacterial biofilm formation. This research sought to examine the effects of desensitising agents on dentinal biofilms using an in vitro model. A constant depth film fermenter (CDFF) was selected to mimic the oral environment and human dentine with exposed tubules was analysed. Calcium sodium phosphosilicate (CSPS) was selected as a model desensitising agent. Dentine discs were treated with pumice or CSPS-containing dentifrices with or without fluoride, or left untreated (control). Dual-species biofilms of Streptococcus mutans and Streptococcus sobrinus were grown in artificial saliva and analysed by viable counts, polymerase chain reaction (PCR) and scanning electron microscopy (SEM). SEM images confirmed the presence of occluded tubules after CSPS application and demonstrated the formation of biofilms containing extracellular matrix material. Analysis of PCR and viable count data using a one-way ANOVA showed no significant differences for bacterial composition for any of the four treatments. There were, however, trends towards increased numbers of bacteria for the pumice and CSPS treated samples which was reversed by the addition of fluoride to CSPS. In conclusion, CSPS was not found to have a significant effect on biofilms and an in vitro model for testing desensitising agents has been developed, however, further work is required to improve the reproducibility of the biofilms formed and to explore the trends seen.}, } @article {pmid30652010, year = {2019}, author = {Drewes, JL and White, JR and Dejea, CM and Fathi, P and Iyadorai, T and Vadivelu, J and Roslani, AC and Wick, EC and Mongodin, EF and Loke, MF and Thulasi, K and Gan, HM and Goh, KL and Chong, HY and Kumar, S and Wanyiri, JW and Sears, CL}, title = {Erratum: Author Correction: High-resolution bacterial 16S rRNA gene profile meta-analysis and biofilm status reveal common colorectal cancer consortia.}, journal = {NPJ biofilms and microbiomes}, volume = {5}, number = {1}, pages = {2}, doi = {10.1038/s41522-018-0078-x}, pmid = {30652010}, issn = {2055-5008}, abstract = {[This corrects the article DOI: 10.1038/s41522-017-0040-3.].}, } @article {pmid30651066, year = {2019}, author = {El-Houssaini, HH and Elnabawy, OM and Nasser, HA and Elkhatib, WF}, title = {Influence of subinhibitory antifungal concentrations on extracellular hydrolases and biofilm production by Candida albicans recovered from Egyptian patients.}, journal = {BMC infectious diseases}, volume = {19}, number = {1}, pages = {54}, pmid = {30651066}, issn = {1471-2334}, mesh = {Antifungal Agents/administration & dosage/*pharmacology ; Aspartic Acid Proteases/metabolism ; Biofilms/drug effects ; Candida albicans/*drug effects/isolation & purification/*metabolism/pathogenicity ; Egypt ; Fluconazole/pharmacology ; Fungal Proteins/metabolism ; Humans ; Hydrolases/*metabolism ; Micafungin/administration & dosage/pharmacology ; Microbial Sensitivity Tests ; Nystatin/administration & dosage/pharmacology ; Phospholipases/metabolism ; Virulence Factors/*metabolism ; }, abstract = {BACKGROUND: Extracellular hydrolases (phospholipase, aspartyl protease and haemolysin) and biofilm production are considered as major virulence factors of the opportunistic pathogenic fungus Candida albicans. However, the impact of antifungal therapy on such virulence attributes is not well investigated. The common antifungal agents may disturb the production of secreted hydrolases as well as biofilm formation. Accordingly, this study addressed the effect of subinhibitory concentrations (sub-MICs) of selected antifungal agents on some virulence factors of C. albicans clinical isolates.

METHODS: C. albicans isolates (n = 32) were recovered from different clinical samples and their identification was confirmed to the species level. Antifungal susceptibility profiles of isolates were determined against (nystatin, fluconazole and micafungin) and minimum inhibitory concentrations (MICs) were interpreted according to Clinical and Laboratory Standards Institute guidelines. Virulence determinants comprising secreted hydrolases (phospholipase, aspartyl protease and haemolysin) and biofilm formation were investigated in the presence of the sub-MICs of the tested antifungal agents.

RESULTS: Treatment of clinical C. albicans isolates with subinhibitory nystatin, fluconazole and micafungin concentrations significantly decreased production of extracellular hydrolases. Nystatin had the greatest inhibitory effect on phospholipase and aspartyl protease production. However, micafungin showed the highest reducing effect on the hemolytic activity of the treated clinical isolates. Moreover, nystatin and micafungin, but not fluconazole, had a noticeable significant impact on inhibiting biofilm formation of C. albicans clinical isolates.

CONCLUSION: Our findings highlighted the significant influences of commonly prescribed antifungal agents on some virulence factors of C. albicans. Accordingly, antifungal therapy may modulate key virulence attributes of C. albicans.}, } @article {pmid30648408, year = {2019}, author = {Itusha, A and Osborne, WJ and Vaithilingam, M}, title = {Enhanced uptake of Cd by biofilm forming Cd resistant plant growth promoting bacteria bioaugmented to the rhizosphere of Vetiveria zizanioides.}, journal = {International journal of phytoremediation}, volume = {21}, number = {5}, pages = {487-495}, doi = {10.1080/15226514.2018.1537245}, pmid = {30648408}, issn = {1549-7879}, mesh = {Bacteria ; Biodegradation, Environmental ; Biofilms ; Cadmium ; *Chrysopogon ; Plant Roots ; RNA, Ribosomal, 16S ; Rhizosphere ; Soil Pollutants/*analysis ; }, abstract = {Heavy metals are the major cause of pollution and cadmium is one among the highly toxic metals discharged into the environment from various industries. The current study was focused on the bioremoval of cadmium by phyto and rhizoremediation approach using Vetiveria zizanioides. The bacterial strains were isolated from wetland paddy rhizosphere soil and the isolate VITJAN13 was found to be a biofilm forming Cd resistant plant growth promoting rhizobacteria (PGPR). The 16S rRNA gene sequencing revealed VITJAN13 to be the closest neighbor of Aeromonas sp. and was submitted to Genbank with the accession number KX770741. Further, pot culture studies indicated that the treatments bioaugmented with VITJAN13 increased the root length and shoot height by 21.4 and 17.36%, respectively as compared to the non-augmented plants. Hence, bioaugmentation of Aeromonas sp. in the rhizosphere of Vetiveria zizanioides enhanced the uptake of cadmium by 67.7% in the soil treated with 15 mg/kg of Cd to that of the phytoremediation setup.}, } @article {pmid30648237, year = {2019}, author = {Venable, ME and Podbielski, MR}, title = {Impact of substrate material on algal biofilm biomass growth.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {7}, pages = {7256-7262}, pmid = {30648237}, issn = {1614-7499}, support = {SU83471501//United States Environmental Protection Agency/ ; }, mesh = {Biofilms/*growth & development ; Biomass ; Chlorella ; Microalgae/*growth & development ; }, abstract = {Algae are being grown for wastewater purification and biofuels production. Their growth on a substrate facilitates these uses by allowing facile separation of algae from the water. Here, we compare different materials to determine which would best serve this purpose. A mixed culture of Anabaena and Chlorella was grown on various synthetic and natural fiber fabric substrates in a trough system with recirculating simulated wastewater. Filter materials studied as substrates for algal growth were muslin, olefin, pellon (acrylic), two types of polyester, and two types of nylon. Biomass accumulation on the various filter substrates was recorded at 7, 14, and 28 days. Filters were weighed before and after the growth periods and changes in dry biomass were recorded. Biomass accumulation was significantly affected by the fabric type. Olefin fostered the greatest increase in biomass while nylon and polyester also supported competitive increases in biomass. Pellon showed the smallest biomass increase and muslin decreased in mass due to material disintegration. Other concerns such as abrasion resistance and UV susceptibility are discussed.}, } @article {pmid30645094, year = {2019}, author = {Keller, N and Bruchmann, J and Sollich, T and Richter, C and Thelen, R and Kotz, F and Schwartz, T and Helmer, D and Rapp, BE}, title = {Study of Biofilm Growth on Slippery Liquid-Infused Porous Surfaces Made from Fluoropor.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {4}, pages = {4480-4487}, doi = {10.1021/acsami.8b12542}, pmid = {30645094}, issn = {1944-8252}, mesh = {Biofilms/*growth & development ; Polymerization ; Polymers/*chemistry/pharmacology ; Porosity ; Pseudomonas aeruginosa/drug effects/growth & development ; }, abstract = {Undesired growth of biofilms represents a fundamental problem for all surfaces in long-term contact with aqueous media. Mature biofilms resist most biocide treatments and often are a pathogenic threat. One way to prevent biofilm growth on surfaces is by using slippery liquid-infused porous surfaces (SLIPS). SLIPS consist of a porous substrate which is infused with a lubricant immiscible with the aqueous medium in which the bacteria are suspended. Because of the lubricant, bacteria cannot attach to the substrate surface and thus formation of the biofilm is prevented. For this purpose, we manufactured substrates with different porosity and surface roughness values via UV-initiated free-radical polymerization in Fluoropor. Fluoropor is a class of highly fluorinated bulk-porous polymers with tunable porosity, which we recently introduced. We investigated the growth of the biofilm on the substrates, showing that a reduced surface roughness is beneficial for the reduction of biofilm growth. Samples of low roughness effectively reduced Pseudomonas aeruginosa biofilm growth for 7 days in a flow chamber experiment. The low-roughness samples also become transparent when infused with the lubricant, making such surfaces ideal for real-time observation of biofilm growth by optical examination.}, } @article {pmid30643885, year = {2019}, author = {Wang, H and Cai, L and Hu, H and Xu, X and Zhou, G}, title = {Complete Genome Sequence of Salmonella enterica Serovar Enteritidis NCM 61, with High Potential for Biofilm Formation, Isolated from Meat-Related Sources.}, journal = {Microbiology resource announcements}, volume = {8}, number = {2}, pages = {}, pmid = {30643885}, issn = {2576-098X}, abstract = {Here, we report the complete genome sequence of strain NMC 61 of Salmonella enterica serovar Enteritidis, which was previously isolated from conveyor belts during chicken slaughter and has the potential to form biofilms on several surfaces. The genome is predicted to contain 110 noncoding small RNAs on the chromosome.}, } @article {pmid30642923, year = {2019}, author = {Henly, EL and Dowling, JAR and Maingay, JB and Lacey, MM and Smith, TJ and Forbes, S}, title = {Biocide Exposure Induces Changes in Susceptibility, Pathogenicity, and Biofilm Formation in Uropathogenic Escherichia coli.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {3}, pages = {}, pmid = {30642923}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Benzalkonium Compounds/pharmacology ; Biguanides/pharmacology ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/drug therapy/microbiology ; Cell Line ; Ciprofloxacin/pharmacology ; Disinfectants/*pharmacology ; Drug Resistance, Bacterial ; Escherichia coli Infections/drug therapy ; Gentamicins/pharmacology ; L Cells ; Mice ; Microbial Sensitivity Tests ; Moths/microbiology ; Nitrofurantoin/pharmacology ; Silver Nitrate/pharmacology ; Triclosan/pharmacology ; Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology ; Uropathogenic Escherichia coli/*drug effects/*pathogenicity ; Virulence/drug effects ; }, abstract = {Uropathogenic Escherichia coli (UPEC) is a frequent cause of catheter-associated urinary tract infection (CAUTI). Biocides have been incorporated into catheter coatings to inhibit bacterial colonization while, ideally, exhibiting low cytotoxicity and mitigating the selection of resistant bacterial populations. We compared the effects of long-term biocide exposure on susceptibility, biofilm formation, and relative pathogenicity in eight UPEC isolates. MICs, minimum bactericidal concentrations (MBCs), minimum biofilm eradication concentrations (MBECs), and antibiotic susceptibilities were determined before and after long-term exposure to triclosan, polyhexamethylene biguanide (PHMB), benzalkonium chloride (BAC), and silver nitrate. Biofilm formation was quantified using a crystal violet assay, and relative pathogenicity was assessed via a Galleria mellonella waxworm model. Cytotoxicity and the resulting biocompatibility index values were determined by use of an L929 murine fibroblast cell line. Biocide exposure resulted in multiple decreases in biocide susceptibility in planktonic and biofilm-associated UPEC. Triclosan exposure induced the largest frequency and magnitude of susceptibility decreases at the MIC, MBC, and MBEC, which correlated with an increase in biofilm biomass in all isolates. Induction of antibiotic cross-resistance occurred in 6/84 possible combinations of bacteria, biocide, and antibiotic. Relative pathogenicity significantly decreased after triclosan exposure (5/8 isolates), increased after silver nitrate exposure (2/8 isolates), and varied between isolates for PHMB and BAC. The biocompatibility index ranked the antiseptic potential as PHMB > triclosan > BAC > silver nitrate. Biocide exposure in UPEC may lead to reductions in biocide and antibiotic susceptibility, changes in biofilm formation, and alterations in relative pathogenicity. These data indicate the multiple consequences of biocide adaptation that should be considered when selecting an anti-infective catheter-coating agent.}, } @article {pmid30642159, year = {2019}, author = {Naha, PC and Liu, Y and Hwang, G and Huang, Y and Gubara, S and Jonnakuti, V and Simon-Soro, A and Kim, D and Gao, L and Koo, H and Cormode, DP}, title = {Dextran-Coated Iron Oxide Nanoparticles as Biomimetic Catalysts for Localized and pH-Activated Biofilm Disruption.}, journal = {ACS nano}, volume = {13}, number = {5}, pages = {4960-4971}, pmid = {30642159}, issn = {1936-086X}, support = {R01 DE025848/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Biomimetic Materials/*pharmacology ; Catalysis ; Cell Line ; Dental Caries/microbiology ; Dextrans/*chemistry ; Ferric Compounds/*chemistry ; Humans ; Hydrogen-Ion Concentration ; Kinetics ; Microbial Viability/drug effects ; Nanoparticles/*chemistry/ultrastructure ; Polysaccharides, Bacterial/metabolism ; }, abstract = {Biofilms are surface-attached bacterial communities embedded within an extracellular matrix that create localized and protected microenvironments. Acidogenic oral biofilms can demineralize the enamel-apatite on teeth, causing dental caries (tooth decay). Current antimicrobials have low efficacy and do not target the protective matrix and acidic pH within the biofilm. Recently, catalytic nanoparticles were shown to disrupt biofilms but lacked a stabilizing coating required for clinical applications. Here, we report dextran-coated iron oxide nanoparticles termed nanozymes (Dex-NZM) that display strong catalytic (peroxidase-like) activity at acidic pH values, target biofilms with high specificity, and prevent severe caries without impacting surrounding oral tissues in vivo. Nanoparticle formulations were synthesized with dextran coatings (molecular weights from 1.5 to 40 kDa were used), and their catalytic performance and bioactivity were assessed. We found that 10 kDa dextran coating provided maximal catalytic activity, biofilm uptake, and antibiofilm properties. Mechanistic studies indicated that iron oxide cores are the source of catalytic activity, whereas dextran on the nanoparticle surface provided stability without blocking catalysis. Dextran-coating facilitated NZM incorporation into exopolysaccharides (EPS) structure and binding within biofilms, which activated hydrogen peroxide (H2O2) for localized bacterial killing and EPS-matrix breakdown. Surprisingly, dextran coating enhanced selectivity toward biofilms while avoiding binding to gingival cells. Furthermore, Dex-NZM/H2O2 treatment significantly reduced the onset and severity of caries lesions (vs control or either Dex-NZM or H2O2 alone) without adverse effects on gingival tissues or oral microbiota diversity in vivo. Therefore, dextran-coated nanozymes have potential as an alternative treatment to control tooth decay and possibly other biofilm-associated diseases.}, } @article {pmid30642091, year = {2019}, author = {Cha, Y and Chun, J and Son, B and Ryu, S}, title = {Characterization and Genome Analysis of Staphylococcus aureus Podovirus CSA13 and Its Anti-Biofilm Capacity.}, journal = {Viruses}, volume = {11}, number = {1}, pages = {}, pmid = {30642091}, issn = {1999-4915}, mesh = {*Biofilms ; *Genome, Viral ; Methicillin-Resistant Staphylococcus aureus/virology ; Microscopy, Electron, Transmission ; Podoviridae/*genetics/*physiology ; Staphylococcus Phages/*genetics/*physiology ; Staphylococcus aureus/*virology ; }, abstract = {Staphylococcus aureus is one of the notable human pathogens that can be easily encountered in both dietary and clinical surroundings. Among various countermeasures, bacteriophage therapy is recognized as an alternative method for resolving the issue of antibiotic resistance. In the current study, bacteriophage CSA13 was isolated from a chicken, and subsequently, its morphology, physiology, and genomics were characterized. This Podoviridae phage displayed an extended host inhibition effect of up to 23 hours of persistence. Its broad host spectrum included methicillin susceptible S. aureus (MSSA), methicillin resistant S. aureus (MRSA), local S. aureus isolates, as well as non-aureus staphylococci strains. Moreover, phage CSA13 could successfully remove over 78% and 93% of MSSA and MRSA biofilms in an experimental setting, respectively. Genomic analysis revealed a 17,034 bp chromosome containing 18 predicted open reading frames (ORFs) without tRNAs, representing a typical chromosomal structure of the staphylococcal Podoviridae family. The results presented here suggest that phage CSA13 can be applicable as an effective biocontrol agent against S. aureus.}, } @article {pmid30639905, year = {2019}, author = {Zhang, G and Li, B and Guo, F and Liu, J and Luan, M and Liu, Y and Guan, Y}, title = {Taxonomic relatedness and environmental pressure synergistically drive the primary succession of biofilm microbial communities in reclaimed wastewater distribution systems.}, journal = {Environment international}, volume = {124}, number = {}, pages = {25-37}, doi = {10.1016/j.envint.2018.12.040}, pmid = {30639905}, issn = {1873-6750}, mesh = {Bacteria/*classification ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Disinfection ; Drinking Water/chemistry ; Microbiota ; Wastewater/*microbiology ; }, abstract = {Compared to drinking water, the higher bacterial abundance, diversity, and organic matter concentration in reclaimed wastewater suggest that it is more likely to form biofilms. Nevertheless, little is known regarding many important aspects of the biofilm ecology in reclaimed wastewater distribution systems (RWDS), such as the long-term microbial community succession and the underlying driving factors. In the present study, by sampling and analysing microbial compositions of pipe wall biofilms from six frequently used pipe materials under NaClOdisinfection (sodium hypochlorite-treated), NONdisinfection (without disinfection), and UVdisinfection (UV-treated) treatments over one year, it was found that the succession of microbial community structure followed a primary succession pattern. This primary succession pattern was reflected as increases in live cell number and α-diversity, along with metagenic succession in taxonomic composition. Proteobacteria, Nitrospirae, Bacteroidetes, Acidobacteria, Planctomycetes, Actinobacteria, and Verrucomicrobia comprised the dominant phyla in biofilm samples. Compared to biofilms in the NaClOdisinfection reactor, the bacterial communities of biofilms in NONdisinfection and UVdisinfection reactors were distributed more evenly among different bacterial phyla. Principal component analysis revealed a clear temporal pattern of microbial community structures in six kinds of pipe wall biofilms albeit a difference in microbial community structures among the three reactors. Adonis testing indicated that the microbial community composition variation caused by disinfection methods (R[2] = 0.283, P < 0.01) was more pronounced than that from the time variable (R[2] = 0.070, P < 0.01) and pipe material (R[2] = 0.057, P < 0.01). Significantly positive correlation between average local abundance and occupancy was observed in biofilm communities of the three reactors, suggesting that the 'core-satellite' model could be applied to identify biofilm-preferential species under specific disinfection conditions in RWDS. The prevalence of family Sphingomonadaceae, known to show chlorine tolerance and powerful biofilm-forming ability in NaClOdisinfection reactors, evidenced the habitat filtering consequent to environment pressure. Correlation-based network analysis revealed that taxonomic relatedness such as similar niches, cooperation, taxa overdispersion, and competition all functioned toward driving the bacterial assembly succession in RWDS.}, } @article {pmid30638998, year = {2019}, author = {Zhang, X and Gao, J and Ling, N and Zeng, H and Tong, L and Zhang, M and Zhang, J and Wu, Q and Ye, Y}, title = {Short communication: Roles of outer membrane protein W on survival, cellular morphology, and biofilm formation of Cronobacter sakazakii in response to oxidative stress.}, journal = {Journal of dairy science}, volume = {102}, number = {3}, pages = {2017-2021}, doi = {10.3168/jds.2018-14643}, pmid = {30638998}, issn = {1525-3198}, mesh = {Bacterial Outer Membrane Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cronobacter sakazakii/cytology/genetics/*physiology ; Longevity ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Oxidative Stress ; }, abstract = {Cronobacter species are a group of opportunistic food-borne pathogens that cause rare but severe infections in neonates. Tolerance to environmental stress in Cronobacter is known; however, factors involved in oxidative stress are undefined. In this study, Cronobacter sakazakii survival, cellular morphology, and biofilm formation in response to oxidative stress were evaluated between the wild type (WT) and an outer membrane protein W (OmpW) mutant. The survival rates of ΔOmpW strain after treatment with 1.0 and 1.5 mM hydrogen peroxide were significantly reduced compared with those of WT. Morphological changes, including cell membrane damage and cell fragmentation, in ΔOmpW were more predominant than those in WT. By crystal violet staining, we also observed increased biomass in ΔOmpW biofilms as compared with WT following treatment with 0.5 and 1.0 mM H2O2. Biofilms using scanning electron microscopy and confocal laser scanning microscopy further confirmed the structural changes of biofilms between WT and ΔOmpW in response to oxidative stress. The current findings show that OmpW contributed to survival of planktonic cells under oxidative stress and the deletion of OmpW facilitated the biofilm formation in C. sakazakii to adapt to oxidative stress.}, } @article {pmid30637904, year = {2019}, author = {Bauermeister, A and Pereira, F and Grilo, IR and Godinho, CC and Paulino, M and Almeida, V and Gobbo-Neto, L and Prieto-Davó, A and Sobral, RG and Lopes, NP and Gaudêncio, SP}, title = {Intra-clade metabolomic profiling of MAR4 Streptomyces from the Macaronesia Atlantic region reveals a source of anti-biofilm metabolites.}, journal = {Environmental microbiology}, volume = {21}, number = {3}, pages = {1099-1112}, doi = {10.1111/1462-2920.14529}, pmid = {30637904}, issn = {1462-2920}, support = {//Alexander van Humboldt Foundation/International ; PCOFUND-GA- 2009-246542//EU 7th Framework Programme (FP7/2007-2013)/International ; 2017/17648-4//Fundação de Amparo à Pesquisa do Estado de São Paulo/International ; IF/00700/2014//Fundação para a Ciência e a Tecnologia/International ; PTDC/QUIQUI/119116/2010//Fundação para a Ciência e a Tecnologia/International ; PTDC/FIS-NAN/0117///Fundação para a Ciência e a Tecnologia/International ; (UID/Multi/04378/2013) and co-financed by the ERDF//European Regional Development Fund/International ; //Portugal2020/International ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/growth & development ; Chromatography, Liquid ; Metabolomics ; Phylogeny ; Staphylococcus aureus/drug effects ; Streptomyces/*chemistry/metabolism ; Tandem Mass Spectrometry ; Terpenes/isolation & purification/*pharmacology ; }, abstract = {The search for new and effective strategies to reduce bacterial biofilm formation is of utmost importance as bacterial resistance to antibiotics continues to emerge. The use of anti-biofilm agents that can disrupt recalcitrant bacterial communities can be an advantageous alternative to antimicrobials, as their use does not lead to the development of resistance mechanisms. Six MAR4 Streptomyces strains isolated from the Madeira Archipelago, at the unexplored Macaronesia Atlantic ecoregion, were used to study the chemical diversity of produced hybrid isoprenoids. These marine actinomycetes were investigated by analysing their crude extracts using LC-MS/MS and their metabolomic profiles were compared using multivariate statistical analysis (principal component analysis), showing a separation trend closely related to their phylogeny. Molecular networking unveiled the presence of a class of metabolites not previously described from MAR4 strains and new chemical derivatives belonging to the napyradiomycin and marinone classes. Furthermore, these MAR4 strains produce metabolites that inhibit biofilm formation of Staphylococcus aureus and Marinobacter hydrocarbonoclasticus. The anti-biofilm activity of napyradiomycin SF2415B3 (1) against S. aureus was confirmed.}, } @article {pmid30635992, year = {2019}, author = {Chen, Z and Yang, G and Lu, S and Chen, D and Fan, S and Xu, J and Wu, B and He, J}, title = {Design and antimicrobial activities of LL-37 derivatives inhibiting the formation of Streptococcus mutans biofilm.}, journal = {Chemical biology & drug design}, volume = {93}, number = {6}, pages = {1175-1185}, doi = {10.1111/cbdd.13419}, pmid = {30635992}, issn = {1747-0285}, mesh = {Amino Acid Sequence ; Animals ; Antimicrobial Cationic Peptides/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Dose-Response Relationship, Drug ; *Drug Design ; Mice ; Microbial Sensitivity Tests ; *Mutation ; NF-kappa B ; RAW 264.7 Cells ; Streptococcus mutans/*drug effects/genetics/metabolism ; Tumor Necrosis Factor-alpha/metabolism ; Cathelicidins ; }, abstract = {Dental plaque is closely related to the occurrence of dental caries, of which the main causative bacterium is Streptococcus mutans (S. mutans). In this study, to create potent antibiofilm agents, we chose a human antimicrobial peptide LL-37 as our starting material and modified it by cutting it shorter and varying its charge and hydrophobicity. The results of anti-S. mutans as well as biofilm inhibitory activity tests indicated that two derivatives, IG-13-1 and IG-13-2, were the most potent one toward both planktonic and biofilm S. mutans cells with the minimal inhibitory concentration of 5.0 μM and minimal biofilm inhibitory concentrations of 5.91 ± 0.91 μM and 7.58 ± 0.23 μM, respectively. The modes of action study showed that IG-13-1 and IG-13-2 were functioned by disrupting the bacterial membrane, causing the leakage of inner contents, thereby leading to the death of bacterial cells eventually. In addition, IG-13-1 and IG-13-2 were able to suppress the expression of proinflammatory cytokine of TNF-α and reduce the level of nuclear transcription factor-κB, which indicated the potential anti-inflammatory activity of these peptides. Conclusively, this study indicated that IG-13-1 and IG-13-2 are potent peptides in both anti-S. mutans and anti-inflammatory activities, therefore, showing a potential application for the prevention and treatment of dental caries.}, } @article {pmid30634919, year = {2019}, author = {Vermee, Q and Cohen, R and Hays, C and Varon, E and Bonacorsi, S and Bechet, S and Thollot, F and Corrard, F and Poyart, C and Levy, C and Raymond, J}, title = {Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae isolated from the nasopharynx of children with acute otitis media.}, journal = {BMC infectious diseases}, volume = {19}, number = {1}, pages = {44}, pmid = {30634919}, issn = {1471-2334}, mesh = {Biofilms/*growth & development ; Child, Preschool ; Haemophilus Infections/microbiology ; Haemophilus influenzae/drug effects/isolation & purification/*physiology ; Heptavalent Pneumococcal Conjugate Vaccine/therapeutic use ; Humans ; Microbial Sensitivity Tests ; Nasopharynx/*microbiology ; Otitis Media/*microbiology ; Pneumococcal Infections/microbiology ; Pneumococcal Vaccines/therapeutic use ; Serogroup ; Streptococcus pneumoniae/drug effects/isolation & purification/*physiology ; }, abstract = {BACKGROUND: Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae has been implicated in the pathogenesis of otitis media, mainly in chronic and recurrent cases. We studied the "in vitro" biofilm production by these 2 species isolated alone or together from the nasopharynx of children with acute otitis media.

METHODS: The studied strains were from 3 pneumococcal conjugate vaccine (PCV) periods: pre-PCV7, post-PCV7/pre-PCV13 and post-PCV13. A modified microtiter plate assay with crystal violet stain was used to study the biofilm production of 182 H. influenzae and 191 S. pneumoniae strains.

RESULTS: Overall, 117/181 (64.6%) H. influenzae and 128/191 (66.8%) S. pneumoniae strains produced biofilm. The proportion of biofilm-producing H. influenzae strains was greater with than without the isolation of S. pneumoniae in the same sample (75.5% vs 52.3%, p = 0.001). Conversely, the proportion of biofilm-producing S. pneumoniae strains was not affected by the presence or not of H. influenzae (66.3% vs 67.4%). S. pneumoniae serotypes 6B, 15B/C, 19A, 35F and 35B were the better biofilm producers (80%). Serotypes 11A, 14, 15A, 19F and 19A were more associated with H. influenzae biofilm-producing strains. Overall, 89/94 (94.6%) of cases with combined isolation showed biofilm production by S. pneumoniae or H. influenzae.

CONCLUSION: This study emphasizes the high proportion of biofilm production by H. influenzae and S. pneumoniae strains isolated from the nasopharynx of children with acute otitis media, which reinforces the results of studies suggesting the importance of biofilm in the pathogenesis of acute otitis media.}, } @article {pmid30632791, year = {2019}, author = {Ramanjeneya, S and Sahoo, SC and Pathak, R and Kumar, M and Vergis, J and Malik, SVS and Barbuddhe, SB and Rawool, DB}, title = {Virulence Potential, Biofilm Formation, and Antibiotic Susceptibility of Listeria monocytogenes Isolated from Cattle Housed in a Particular Gaushala (Cattle Shelter) and Organized Farm.}, journal = {Foodborne pathogens and disease}, volume = {16}, number = {3}, pages = {214-220}, doi = {10.1089/fpd.2018.2494}, pmid = {30632791}, issn = {1556-7125}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cattle ; Colony Count, Microbial/veterinary ; Dairying ; Farms ; Female ; India ; Listeria monocytogenes/*drug effects/genetics/isolation & purification ; Listeriosis/drug therapy/*veterinary ; Microbial Sensitivity Tests/veterinary ; Milk ; *Virulence ; }, abstract = {OBJECTIVES: The occurrence of Listeria monocytogenes was studied by using cultural and serological methods in cattle housed in a particular gaushala (cattle shelter) and organized dairy farm.

MATERIALS AND METHODS: A total of 1201 samples from cattle comprising blood (n = 207), milk (n = 203), vaginal swabs (n = 210), and serum (n = 207) from an organized farm (n = 210) and blood (n = 100), milk (n = 74), vaginal swabs (n = 100), and serum (n = 100) from a gaushala (n = 100) were collected and analyzed for L. monocytogenes. All samples excluding serum were analyzed for isolation and identification of L. monocytogenes, while the serum samples were screened for seropositivity. The isolates were further subjected to assess their virulence potential (in vitro and in vivo), biofilm formation ability, and antibiotic susceptibility patterns.

RESULTS: Four L. monocytogenes strains were isolated from the cattle; three (0.48%) from the organized farm and one (0.36%) from the gaushala. On serological screening of cattle from the organized dairy farm, 16.42% were found to be positive for antibodies against listeriolysin O, while cattle from the gaushala revealed 36% seropositivity. Furthermore, on characterization of the isolates for their pathogenic potential and biofilm-forming ability, all were found to be pathogenic by both in vitro and in vivo assays and were weak to moderate biofilm formers. The minimum inhibition concentration (MIC) of recovered isolates revealed resistance for ampicillin by two L. monocytogenes isolates (MIC >256 μg/mL), whereas three L. monocytogenes isolates were intermediately resistant (MIC >4 μg/mL) and one resistant against amoxicillin (MIC >8 μg/mL). However, all four isolates were susceptible to gentamicin, cotrimoxazole, and erythromycin.

CONCLUSIONS: Isolation of virulent and antibiotic-resistant strains of L. monocytogenes warrants the need for epidemiological surveillance, antimicrobial susceptibility, and implementation of control measures to combat the occurrence of L. monocytogenes infection in animals as well as humans.}, } @article {pmid30630718, year = {2019}, author = {Qiu, MN and Wang, F and Chen, SY and Wang, PC and Fu, YH and Liu, YY and Wang, X and Wang, FB and Wang, C and Yang, HW and Wu, Y and Zhu, SY and Zhou, HB and Chen, WM and Lin, J and Zheng, JX and Sun, PH}, title = {Novel 2, 8-bit derivatives of quinolines attenuate Pseudomonas aeruginosa virulence and biofilm formation.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {29}, number = {5}, pages = {749-754}, doi = {10.1016/j.bmcl.2018.12.068}, pmid = {30630718}, issn = {1464-3405}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Lac Operon ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Quinolines/chemistry/*pharmacology ; Quorum Sensing ; Virulence/*drug effects ; }, abstract = {Signal molecules are stimulators of multiple quroum-sensing virulence and biofilm formation. Small molecule analogues have been suspected as a potent inhibitor in therapeutic strategy. Herein, we synthesized a series of small molecule compounds from the 2, 8-bit derivatives of quinoline by Suzuki coupling reaction. We found that these compounds have the biofilm inhibitory effect in normal condition instead of phosphate limitation state. Furthermore, lacZ reporter strain assay and rhamnolipids as well as pyocyanin experiments showed that these compounds did not affect las and pqs system but reduced the expression of rhl. All these results suggest that quinoline derivatives can be treated as potent inhibitors against biofilm and reduce virulence through the rhl system. This research will be useful in designing new quorum sensing inhibitors to attenuate the infection of bacteria.}, } @article {pmid30629548, year = {2018}, author = {Cheng, L and Flavigny, RM and Hossain, MI and Charles, W and Cord-Ruwisch, R}, title = {Proof of concept of wastewater treatment via passive aeration SND using a novel zeolite amended biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {78}, number = {10}, pages = {2204-2213}, doi = {10.2166/wst.2018.504}, pmid = {30629548}, issn = {0273-1223}, mesh = {*Biofilms ; *Bioreactors ; Nitrogen ; Sewage ; Waste Disposal, Fluid/*methods ; Wastewater ; Zeolites ; }, abstract = {The current paper describes a novel passive aeration simultaneous nitrification and denitrification (PASND) zeolite amended biofilm reactor that removes organic carbon and nitrogen from wastewater with low-energy consumption. Next to the ammonium oxidizing bacteria (AOB), this reactor contained naturally enriched glycogen accumulating organisms (GAOs) and zeolite powder to initially adsorb BOD (acetate) and ammonium (NH4 [+]-N) from synthetic wastewater under anaerobic conditions. Draining of the treated wastewater exposed the biofilm directly to air enabling low-energy oxygen supply by passive aeration. This allowed the adsorbed ammonium to be oxidized by the AOB and the produced nitrite and nitrate to be reduced simultaneously by the GAOs using the adsorbed BOD (stored as PHAs) as carbon source. Overall, with an operation mode of 1 h anaerobic and 4 h aerobic phase, the nutrient removal efficiency after single treatment was about 94.3% for BOD and 72.2% for nitrogen (NH4 [+]-N). As high-energy aeration of the bulk solution for oxygen supply is completely avoided, the energy requirement of the proposed PASND biofilm reactor can be theoretically cut down to more than 50% compared to the traditional activated sludge process.}, } @article {pmid30628340, year = {2019}, author = {Liu, C and Wang, CC and Chen, XX and Zhang, J and Zhang, RN and Zhang, L}, title = {[Biological Nitrogen Removal Process in a Microbubble-aerated Biofilm Reactor Treating Low C/N Wastewater].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {40}, number = {2}, pages = {754-760}, doi = {10.13227/j.hjkx.201807085}, pmid = {30628340}, issn = {0250-3301}, mesh = {Bacteria ; *Biofilms ; *Bioreactors ; Carbon ; Denitrification ; Microbubbles ; Nitrification ; Nitrogen/*isolation & purification ; *Wastewater ; }, abstract = {The microbubble-aerated biofilm reactor as a new treatment process combines microbubble aeration technology with aerobic biological treatment. A microbubble aerated biofilm reactor was used in this study to treat low C/N ratio wastewater at a low air/water ratio. The process and performance of biological nitrogen removal were investigated, and the functional bacterial populations for nitrogen removal in the biofilm were analyzed. The results showed that the biological nitrogen removal process was converted from simultaneous nitrification-denitrification to simultaneous partial nitrification, ANAMMOX and denitrification (SNAD) processes when DO concentration was controlled by an air/water ratio of lower than 1:2 and the influent C/N ratio was reduced. As a result, the efficient biological nitrogen removal performance was achieved when treating low C/N ratio wastewater. When the DO concentration was lower than 1.0 mg·L[-1] and the influent C/N ratio was 1:2.8, the SNAD process became dominant for biological nitrogen removal. In this case, the average total nitrogen (TN) removal efficiency was 76.3%, and the average TN loading rate removed was 1.42 kg·(m[3]·d)[-1]. In addition, it was estimated that 86.0% of TN removal was attributed to the ANAMMOX process. The relative abundances of ammonia-oxidizing bacteria populations and ANAMMOX bacteria populations in the biofilm increased gradually, while the relative abundances of nitrite-oxidizing bacteria populations and denitrifying bacteria populations decreased gradually, with a decrease in influent C/N ratio. The variation of functional bacterial populations for nitrogen removal was consistent with the conversion of nitrogen removal process to SNAD process.}, } @article {pmid30624468, year = {2019}, author = {Santos, DMSD and Pires, JG and Braga, AS and Salomão, PMA and Magalhães, AC}, title = {Comparison between static and semi-dynamic models for microcosm biofilm formation on dentin.}, journal = {Journal of applied oral science : revista FOB}, volume = {27}, number = {}, pages = {e20180163}, pmid = {30624468}, issn = {1678-7765}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Dental Caries/*microbiology ; Dentin/*microbiology ; Humans ; Microbial Viability ; Microradiography ; *Models, Biological ; Saliva/microbiology ; Surface Properties ; Time Factors ; Tooth Demineralization/microbiology ; }, abstract = {OBJECTIVE: Microcosm biofilm has been applied to induce carious lesions in dentin. However, no study has been done to compare the impact of the type of model for providing nutrients to microcosm biofilm formation on dentin. This study compared the performance of two kinds of models (static and semi-dynamic) on the biofilm formation and the development of dentin carious lesions.

MATERIAL AND METHODS: In both models, biofilm was produced using inoculum from pooled human saliva mixed with McBain saliva for the first 8 h (5% CO2 and 37°C). Afterwards, for the static model, the samples were placed in 24-wells microplate containing McBain saliva with 0.2% sucrose, which was replaced at 24 h. In the semi-dynamic model, the samples were submitted to artificial mouth system with continuous flow of McBain saliva with 0.2% sucrose (0.15 ml/min, 37°C) for 10 h a day (for the other 14 h, no flow was applied, similarly to the static model). After 5 days, biofilm viability was measured by fluorescence and dentin demineralization by transverse microradiography.

RESULTS: Biofilm viability was significantly lower for the static compared with semi-dynamic model, while dentin demineralization was significantly higher for the first one (p<0.05). The static model was able to produce a higher number of typical subsurface lesions compared with the semi-dynamic model (p<0.05).

CONCLUSIONS: The type of model (static and semi-dynamic) applied in the microcosm biofilm may have influence on it's viability and the severity/profile of dentin carious lesions.}, } @article {pmid30623876, year = {2019}, author = {Tang, C and Sun, P and Yang, J and Huang, Y and Wu, Y}, title = {Kinetics simulation of Cu and Cd removal and the microbial community adaptation in a periphytic biofilm reactor.}, journal = {Bioresource technology}, volume = {276}, number = {}, pages = {199-203}, doi = {10.1016/j.biortech.2019.01.001}, pmid = {30623876}, issn = {1873-2976}, mesh = {Adaptation, Physiological ; *Biofilms ; Bioreactors ; Cadmium/*isolation & purification ; Copper/*isolation & purification ; Kinetics ; *Microbiota ; Wastewater/*chemistry ; Water Pollutants, Chemical/*isolation & purification ; }, abstract = {Periphytic biofilm reactor (PBfR) shows great potential in pollutants removal. However, few studies were focused on mathematical model of pollutants removal in PBfR. A three-step PBfR was designed and a new model was developed to simulate the kinetics of Cu and Cd removal from simulated wastewater. The results show that the PBfR could remove 99.0% Cu and 99.7% Cd from liquid wastewater. The experiment data could be well fitted with a high correlation coefficients both for Cu and Cd. The microbial community in the PBfR could be self-adjusted to tolerate the toxicities of Cu and Cd, resulting in sustainable and high decontamination efficiencies. The eukaryote in the PBfR played a vital role in Cu and Cd removal. The prokaryote showed negative effect on Cu and Cd removal, though it had more diversity than eukaryote. This study provides a new approach for Cu and Cd removal and their kinetics simulation in photoautotrophic bioreactor.}, } @article {pmid30623561, year = {2019}, author = {Hochstrasser, R and Kessler, A and Sahr, T and Simon, S and Schell, U and Gomez-Valero, L and Buchrieser, C and Hilbi, H}, title = {The pleiotropic Legionella transcription factor LvbR links the Lqs and c-di-GMP regulatory networks to control biofilm architecture and virulence.}, journal = {Environmental microbiology}, volume = {21}, number = {3}, pages = {1035-1053}, doi = {10.1111/1462-2920.14523}, pmid = {30623561}, issn = {1462-2920}, support = {ANR-10-LABX-62-IBEID//Agence Nationale de la Recherche/International ; 31003A_153200//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung/International ; //Fondation pour la Recherche Médicale/International ; //Institut Pasteur/International ; 31003A_175557/SNSF_/Swiss National Science Foundation/Switzerland ; 31003A_153200/SNSF_/Swiss National Science Foundation/Switzerland ; }, mesh = {4-Butyrolactone/analogs & derivatives ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; *Gene Expression Regulation, Bacterial ; *Gene Regulatory Networks ; Legionella pneumophila/*genetics/pathogenicity ; Legionnaires' Disease/microbiology ; Quorum Sensing ; Transcription Factors/*metabolism ; Virulence ; }, abstract = {The causative agent of Legionnaires' disease, Legionella pneumophila, colonizes amoebae and biofilms in the environment. The opportunistic pathogen employs the Lqs (Legionella quorum sensing) system and the signalling molecule LAI-1 (Legionella autoinducer-1) to regulate virulence, motility, natural competence and expression of a 133 kb genomic "fitness island", including a putative novel regulator. Here, we show that the regulator termed LvbR is an LqsS-regulated transcription factor that binds to the promoter of lpg1056/hnox1 (encoding an inhibitor of the diguanylate cyclase Lpg1057), and thus, regulates proteins involved in c-di-GMP metabolism. LvbR determines biofilm architecture, since L. pneumophila lacking lvbR accumulates less sessile biomass and forms homogeneous mat-like structures, while the parental strain develops more compact bacterial aggregates. Comparative transcriptomics of sessile and planktonic ΔlvbR or ΔlqsR mutant strains revealed concerted (virulence, fitness island, metabolism) and reciprocally (motility) regulated genes in biofilm and broth respectively. Moreover, ΔlvbR is hyper-competent for DNA uptake, defective for phagocyte infection, outcompeted by the parental strain in amoebae co-infections and impaired for cell migration inhibition. Taken together, our results indicate that L. pneumophila LvbR is a novel pleiotropic transcription factor, which links the Lqs and c-di-GMP regulatory networks to control biofilm architecture and pathogen-host cell interactions.}, } @article {pmid30623530, year = {2019}, author = {Race, J and Zilm, P and Ratnayake, J and Fitzsimmons, T and Marchant, C and Cathro, P}, title = {Efficacy of laser and ultrasonic-activated irrigation on eradicating a mixed-species biofilm in human mesial roots.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {45}, number = {3}, pages = {317-324}, doi = {10.1111/aej.12334}, pmid = {30623530}, issn = {1747-4477}, mesh = {Biofilms ; *Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; *Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Therapeutic Irrigation ; Ultrasonics ; }, abstract = {This study investigated the efficacy of Er,Cr:YSGG laser and ultrasonic activated irrigation on eradicating a mixed-species biofilm grown in root canals with complex anatomy. The biofilm was grown over 4-weeks in the root canals of decoronated human mandibular molar teeth. Control roots received no further treatment. The remaining roots were chemomechanically prepared using different irrigating protocols: 4% NaOCl and 15% EDTAC with ultrasonic activated irrigation and laser activated irrigation using power settings of 0.5 W and 0.75 W. Cellular viability was determined using serial plating. One tooth from each group was subjected to qualitative SEM analysis. Quantification by culturing revealed significant differences between control group and all other treatment groups. This study demonstrated that chemomechanical irrigation with laser and ultrasonic activated irrigation significantly reduced the bacterial load from complex root canal systems; however, there were no significant differences found between the experimental groups.}, } @article {pmid30622962, year = {2018}, author = {Mohamed, MA and Nasr, M and Elkhatib, WF and Eltayeb, WN}, title = {In Vitro Evaluation of Antimicrobial Activity and Cytotoxicity of Different Nanobiotics Targeting Multidrug Resistant and Biofilm Forming Staphylococci.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {7658238}, pmid = {30622962}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Drug Evaluation, Preclinical/methods ; Drug Resistance, Multiple, Bacterial/*drug effects ; Hepatocytes/metabolism/microbiology/pathology ; Rats ; *Software ; Staphylococcal Infections/*drug therapy/metabolism/pathology ; Staphylococcus/*physiology ; }, abstract = {Antibiotic-resistant and biofilm-forming bacteria have surprisingly increased over recent years. On the contrary, the rate of development of new antibiotics to treat these emerging superbugs is very slow. Therefore, the aim of this study was to prepare novel nanobiotic formulations to improve the antimicrobial activity of three antibiotics (linezolid, doxycycline, and clindamycin) against Staphylococci. Antibiotics were formulated as nanoemulsions and evaluated for their antimicrobial activities and cytotoxicities. Cytotoxicity of the conventional antibiotics and nanobiotics was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on rat hepatocytes. Half-maximal inhibitory concentration (IC50) was estimated from an experimentally derived dose-response curve for each concentration using GraphPad Prism software. Upon quantitative assessment of Staphylococcus biofilm formation, eighty-four isolates (66.14 %) were biofilm forming. Linezolid and doxycycline nanobiotics exhibited promising antibacterial activities. On the contrary, clindamycin nanobiotic exhibited poor antibacterial activity. Minimum biofilm inhibitory concentrations showed that 73.68 %, 45.6%, and 5.2% of isolates were sensitive to linezolid, doxycycline, and clindamycin nanobiotics, respectively. Results of this study revealed that antibiotics loaded in nanosystems had a higher antimicrobial activity and lower cytotoxicities as compared to those of conventional free antibiotics, indicating their potential therapeutic values.}, } @article {pmid30622185, year = {2019}, author = {Andreasen, M and Meisl, G and Taylor, JD and Michaels, TCT and Levin, A and Otzen, DE and Chapman, MR and Dobson, CM and Matthews, SJ and Knowles, TPJ}, title = {Physical Determinants of Amyloid Assembly in Biofilm Formation.}, journal = {mBio}, volume = {10}, number = {1}, pages = {}, pmid = {30622185}, issn = {2150-7511}, support = {MR/P028225/1/MRC_/Medical Research Council/United Kingdom ; R01 GM118651/GM/NIGMS NIH HHS/United States ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Amyloid/*metabolism ; Biofilms/*growth & development ; Chemical Phenomena ; Escherichia coli/*physiology ; Escherichia coli Proteins/*metabolism ; Macromolecular Substances/metabolism ; Protein Aggregates ; *Protein Multimerization ; Pseudomonas fluorescens/*physiology ; }, abstract = {A wide range of bacterial pathogens have been shown to form biofilms, which significantly increase their resistance to environmental stresses, such as antibiotics, and are thus of central importance in the context of bacterial diseases. One of the major structural components of these bacterial biofilms are amyloid fibrils, yet the mechanism of fibril assembly and its importance for biofilm formation are currently not fully understood. By studying fibril formation in vitro, in a model system of two common but unrelated biofilm-forming proteins, FapC from Pseudomonas fluorescens and CsgA from Escherichia coli, we found that the two proteins have a common aggregation mechanism. In both systems, fibril formation proceeds via nucleated growth of linear fibrils exhibiting similar measured rates of elongation, with negligible fibril self-replication. These similarities between two unrelated systems suggest that convergent evolution plays a key role in tuning the assembly kinetics of functional amyloid fibrils and indicates that only a narrow window of mechanisms and assembly rates allows for successful biofilm formation. Thus, the amyloid assembly reaction is likely to represent a means for controlling biofilm formation, both by the organism and by possible inhibitory drugs.IMPORTANCE Biofilms are generated by bacteria, embedded in the formed extracellular matrix. The biofilm's function is to improve the survival of a bacterial colony through, for example, increased resistance to antibiotics or other environmental stresses. Proteins secreted by the bacteria act as a major structural component of this extracellular matrix, as they self-assemble into highly stable amyloid fibrils, making the biofilm very difficult to degrade by physical and chemical means once formed. By studying the self-assembly mechanism of the fibrils from their monomeric precursors in two unrelated bacteria, our experimental and theoretical approaches shed light on the mechanism of functional amyloid assembly in the context of biofilm formation. Our results suggest that fibril formation may be a rate-limiting step in biofilm formation, which in turn has implications on the protein self-assembly reaction as a target for potential antibiotic drugs.}, } @article {pmid30621792, year = {2019}, author = {Wu, S and Huang, F and Zhang, H and Lei, L}, title = {Staphylococcus aureus biofilm organization modulated by YycFG two-component regulatory pathway.}, journal = {Journal of orthopaedic surgery and research}, volume = {14}, number = {1}, pages = {10}, pmid = {30621792}, issn = {1749-799X}, support = {18PJ464//The Science and Technology Project of the Health Planning Committee of Sichuan/ ; 2018SZ0125//Sichuan Provincial Natural Science Foundation of China/ ; }, mesh = {Adult ; Bacterial Proteins/isolation & purification/*physiology ; Biofilms/*growth & development ; Female ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/isolation & purification/physiology ; Middle Aged ; Signal Transduction/*physiology ; Staphylococcal Infections/diagnosis/genetics ; Staphylococcus aureus/isolation & purification/*physiology ; Young Adult ; }, abstract = {BACKGROUND: Staphylococcus aureus (S. aureus) infection accounts for more than 50% of the osteomyelitis cases. Currently, methicillin-resistant S. aureus (MRSA) strains present an urgent medical problem. The YycFG two-component regulatory system (TCS) can allow bacteria to rapidly adapt to physical, chemical, and biological stresses. To define the role of YycFG in modulation virulence of S. aureus in osteomyelitis, we isolated clinical MRSA strains and compared these with ATCC29213 methicillin-sensitive S. aureus (MSSA).

METHODS: In the present study, 13 MRSA strains from chronic osteomyelitis tissues were isolated. The in-depth sequencing of 16S rRNA amplicons of the samples was conducted. Bacterial growth was monitored, and biofilm biomass was determined by crystal violet microtiter assay. Furthermore, quantitative RT-PCR analysis was adopted to identify the expression of yycF/G/H and icaA/D in MRSA and MSSA strains. Analysis of variance with one-way ANOVA was used for statistical analysis.

RESULTS: The in-depth sequencing of 16S rRNA amplicons of the clinical samples indicated a polymicrobial infection, with the phylum Firmicutes made up 13% of the microbial population. The MRSA strains showed an accelerated growth rate compared to the MSSA strains. Of note, MRSA biofilms showed an accumulation of an intercellular polysaccharides matrix and enhanced biomass upon microscopic examination. Furthermore, MRSA strains had a higher expression of the yycF/G/H and icaA/D genes and adhesion force.

CONCLUSIONS: These data suggested the roles of intercellular polysaccharide in S. aureus pathogenesis, indicating a possible association between YycFG pathways and MRSA strain virulence.}, } @article {pmid30621556, year = {2019}, author = {Srinivasan, A and Ramasubramanian, AK and Lopez-Ribot, JL}, title = {Nano-biofilm Arrays as a Novel Universal Platform for Microscale Microbial Culture and High-Throughput Downstream Applications.}, journal = {Current medicinal chemistry}, volume = {26}, number = {14}, pages = {2529-2535}, pmid = {30621556}, issn = {1875-533X}, support = {R01 AI119554/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; UL1 TR001120/TR/NCATS NIH HHS/United States ; UL1 TR002645/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*pharmacology ; *Biofilms ; High-Throughput Screening Assays/*methods ; Humans ; *Nanotechnology ; }, abstract = {Biofilms are the predominant mode of microbial growth and it is now fully accepted that a majority of infections in humans are associated with a biofilm etiology. Biofilms are defined as attached and structured microbial communities surrounded by a protective exopolymeric matrix. Importantly, sessile microorganisms growing within a biofilm are highly resistant to antimicrobial agents. Thus, there is an urgent need to develop new and improved anti-biofilm therapies. Unfortunately, most of the current techniques for in-vitro biofilm formation are not compatible with high throughput screening techniques that can speed up discovery of new drugs with anti-biofilm activity. To try to overcome this major impediment, our group has developed a novel technique consisting of micro-scale culture of microbial biofilms on a microarray platform. Using this technique, hundreds to thousands of microbial biofilms, each with a volume of approximately 30-50 nanolitres, can be simultaneously formed on a standard microscope slide. Despite more than three orders of magnitude of miniaturization over conventional biofilms, these nanobiofilms display similar growth, structural and phenotypic properties, including antibiotic drug resistance. These nanobiofilm chips are amenable to automation, drastically reducing assay volume and costs. This technique platform allows for true high-throughput screening in search for new anti-biofilm drugs.}, } @article {pmid30621457, year = {2018}, author = {Yüksel, FN and Buzrul, S and Akçelik, M and Akçelik, N}, title = {Inhibition and eradication of Salmonella Typhimurium biofilm using P22 bacteriophage, EDTA and nisin.}, journal = {Biofouling}, volume = {34}, number = {9}, pages = {1046-1054}, doi = {10.1080/08927014.2018.1538412}, pmid = {30621457}, issn = {1029-2454}, mesh = {*Bacteriophage P22 ; Biofilms/*drug effects/growth & development ; Edetic Acid/*pharmacology ; Models, Theoretical ; Nisin/*pharmacology ; Salmonella typhimurium/*growth & development/virology ; }, abstract = {P22 phage >10[5] PFU ml[-1] could be used to inhibit Salmonella Typhimurium biofilm formation by 55-80%. Concentrations of EDTA >1.25 mM and concentrations of nisin >1,200 µg ml[-1] were also highly effective in reducing S. Typhimurium biofilm formation (≥96% and ≥95% reductions were observed, respectively). A synergistic effect was observed when EDTA and nisin were combined whereas P22 phage in combination with nisin had no synergistic impact on biofilm formation. Triple combination of P22 phage, EDTA and nisin could be also used to inhibit biofilm formation (≥93.2%) at a low phage titer (10[2] PFU ml[-1]), and low EDTA (1.25 mM) and nisin (9.375 µg ml[-1]) concentrations. A reduction of 70% in the mature biofilm was possible when 10[7] PFU ml[-1] of P22 phage, 20 mM of EDTA and 150 μg ml[-1] of nisin were used in combination. This study revealed that it could be possible to reduce biofilm formation by S. Typhimurium by the use of P22 phage, EDTA and nisin, either alone or in combination. Although, removal of the mature biofilm was more difficult, the triple combination could be successfully used for mature biofilm of S. Typhimurium.}, } @article {pmid30620265, year = {2019}, author = {Heindl, JE and Crosby, D and Brar, S and Pinto, JF and Singletary, T and Merenich, D and Eagan, JL and Buechlein, AM and Bruger, EL and Waters, CM and Fuqua, C}, title = {Reciprocal control of motility and biofilm formation by the PdhS2 two-component sensor kinase of Agrobacterium tumefaciens.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {2}, pages = {146-162}, pmid = {30620265}, issn = {1465-2080}, support = {R01 GM080546/GM/NIGMS NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; R01 GM120337/GM/NIGMS NIH HHS/United States ; R03 AI130554/AI/NIAID NIH HHS/United States ; }, mesh = {Agrobacterium tumefaciens/genetics/growth & development/metabolism/*physiology ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Epistasis, Genetic ; Gene Expression Regulation, Bacterial ; Histidine Kinase/genetics/*metabolism ; *Locomotion ; Mutation ; Phosphorylation ; Polysaccharides, Bacterial/biosynthesis ; Signal Transduction ; Transcription Factors/genetics/metabolism ; }, abstract = {A core regulatory pathway that directs developmental transitions and cellular asymmetries in Agrobacterium tumefaciens involves two overlapping, integrated phosphorelays. One of these phosphorelays putatively includes four histidine sensor kinase homologues, DivJ, PleC, PdhS1 and PdhS2, and two response regulators, DivK and PleD. In several different alphaproteobacteria, this pathway influences a conserved downstream phosphorelay that ultimately controls the phosphorylation state of the CtrA master response regulator. The PdhS2 sensor kinase reciprocally regulates biofilm formation and swimming motility. In the current study, the mechanisms by which the A. tumefaciens sensor kinase PdhS2 directs this regulation are delineated. PdhS2 lacking a key residue implicated in phosphatase activity is markedly deficient in proper control of attachment and motility phenotypes, whereas a kinase-deficient PdhS2 mutant is only modestly affected. A genetic interaction between DivK and PdhS2 is revealed, unmasking one of several connections between PdhS2-dependent phenotypes and transcriptional control by CtrA. Epistasis experiments suggest that PdhS2 may function independently of the CckA sensor kinase, the cognate sensor kinase for CtrA, which is inhibited by DivK. Global expression analysis of the pdhS2 mutant reveals a restricted regulon, most likely functioning through CtrA to separately control motility and regulate the levels of the intracellular signal cyclic diguanylate monophosphate (cdGMP), thereby affecting the production of adhesive polysaccharides and attachment. We hypothesize that in A. tumefaciens the CtrA regulatory circuit has expanded to include additional inputs through the addition of PdhS-type sensor kinases, likely fine-tuning the response of this organism to the soil microenvironment.}, } @article {pmid30619958, year = {2018}, author = {Khatoon, Z and McTiernan, CD and Suuronen, EJ and Mah, TF and Alarcon, EI}, title = {Bacterial biofilm formation on implantable devices and approaches to its treatment and prevention.}, journal = {Heliyon}, volume = {4}, number = {12}, pages = {e01067}, pmid = {30619958}, issn = {2405-8440}, abstract = {In living organisms, biofilms are defined as complex communities of bacteria residing within an exopolysaccharide matrix that adheres to a surface. In the clinic, they are typically the cause of chronic, nosocomial, and medical device-related infections. Due to the antibiotic-resistant nature of biofilms, the use of antibiotics alone is ineffective for treating biofilm-related infections. In this review, we present a brief overview of concepts of bacterial biofilm formation, and current state-of-the-art therapeutic approaches for preventing and treating biofilms. Also, we have reviewed the prevalence of such infections on medical devices and discussed the future challenges that need to be overcome in order to successfully treat biofilms using the novel technologies being developed.}, } @article {pmid30619638, year = {2018}, author = {Di Salle, A and Spagnuolo, G and Conte, R and Procino, A and Peluso, G and Rengo, C}, title = {Effects of various prophylactic procedures on titanium surfaces and biofilm formation.}, journal = {Journal of periodontal & implant science}, volume = {48}, number = {6}, pages = {373-382}, pmid = {30619638}, issn = {2093-2278}, abstract = {PURPOSE: The aim of this study was to evaluate the effects of various prophylactic treatments of titanium implants on bacterial biofilm formation, correlating surface modifications with the biofilms produced by Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and bacteria isolated from saliva.

METHODS: Pure titanium disks were treated with various prophylactic procedures, and atomic force microscopy (AFM) was used to determine the degree to which surface roughness was modified. To evaluate antibiofilm activity, we used P. aeruginosa PAO1, S. aureus, and saliva-isolated Streptococcus spp., Bacteroides fragilis, and Staphylococcus epidermidis.

RESULTS: AFM showed that the surface roughness increased after using the air-polishing device and ultrasonic scaler, while a significant reduction was observed after using a curette or polishing with Detartrine ZTM (DZ) abrasive paste. In addition, we only observed a significant (P<0.01) reduction in biofilm formation on the DZ-treated implant surfaces.

CONCLUSION: In this study, both AFM and antibiofilm analyses indicated that using DZ abrasive paste could be considered as the prophylactic procedure of choice for managing peri-implant lesions and for therapy-resistant cases of periodontitis.}, } @article {pmid30619103, year = {2018}, author = {Gangneux, JP and Cornet, M and Bailly, S and Fradin, C and Féger, C and Timsit, JF and Leroy, O and Sendid, B and Bougnoux, ME}, title = {Clinical Impact of Antifungal Susceptibility, Biofilm Formation and Mannoside Expression of Candida Yeasts on the Outcome of Invasive Candidiasis in ICU: An Ancillary Study on the Prospective AmarCAND2 Cohort.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2907}, pmid = {30619103}, issn = {1664-302X}, abstract = {Background: The link between Candida phenotypical characteristics and invasive candidiasis (IC) prognosis is still partially unknown. Methods: Candida strains isolated during the AmarCAND2 study were centrally analyzed for species identification, antifungal susceptibility, biofilm formation, and expression of surface and glycoconjugate mannosides. Correlation between these phenotypical features and patient outcome was sought using a multivariable Cox survival model. Results: Candida albicans was predominant (65.4%, n = 285), with a mortality rate significantly lower than that in patients with non-albicans strains [HR 0.67 (0.46-1.00), p = 0.048]. The rate of fluconazole-resistant strains was low (C. albicans and Candida glabrata: 3.5 and 6.2%, respectively) as well as caspofungin-resistant ones (1 and 3.1%, respectively). Early biofilm formation was less frequent among C. albicans (45.4%) than among non-albicans (81.2%). While the strains of C. albicans showed variable levels of surface mannosides expression, strains isolated from candidemia exhibited a high expression of β-man, which was correlated with an increased mortality (p = 0.02). Conclusion: Candida albicans IC were associated with lower mortality, and with strains that exhibited less frequently early biofilm formation than non-albicans strains. A high expression of β-man was associated with increased IC mortality. Further studies are warranted to confirm this data and to evaluate other virulence factors in yeasts.}, } @article {pmid30618736, year = {2018}, author = {Kerkoub, N and Panda, SK and Yang, MR and Lu, JG and Jiang, ZH and Nasri, H and Luyten, W}, title = {Bioassay-Guided Isolation of Anti-Candida Biofilm Compounds From Methanol Extracts of the Aerial Parts of Salvia officinalis (Annaba, Algeria).}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {1418}, pmid = {30618736}, issn = {1663-9812}, abstract = {Salvia officinalis is frequently used in traditional Algerian medicine to treat diverse microbial infections, including oral and vaginal candidiasis. The aerial parts of S. officinalis collected in Annaba, Algeria were extracted in parallel by maceration with four solvents viz. hexane, acetone, methanol and water. All the extracts were tested in vitro against several Candida species: C. albicans, C. glabrata, and C. parapsilosis. Furthermore, the activity against biofilm-forming C. albicans was investigated using bioassay-guided fractionation. A large-scale extract was prepared via maceration in methanol, followed by fractionation on a silica gel column using increasingly polar mixtures of n-hexane, ethyl acetate, methanol, and acetic acid as mobile phase, to yield a total of 150 fractions. Two major active fractions (F-31 and F-39), were further separated by HPLC, resulting in several active chromatographic peaks. Carnosol and 12-methoxy-trans-carnosic acid were isolated as two major active compounds, and identified by a combination of NMR and mass spectrometry. The biofilm inhibitory concentration showed that 12-methoxy-trans-carnosic acid is more effective than carnosol with BIC50 values of 94 μM (95% confidence interval, 78.9-112.1 μM) and 314 μM (95% confidence interval, 200.7-491.2 μM), respectively. The present study supports the traditional use of sage in the treatment of various fungal infections caused by Candida. Further studies of the bioactive compounds in an in vivo Candida biofilm model are required to validate their clinical potential as antifungals.}, } @article {pmid30618296, year = {2018}, author = {Peng, G and Hou, X and Zhang, W and Song, M and Yin, M and Wang, J and Li, J and Liu, Y and Zhang, Y and Zhou, W and Li, X and Li, G}, title = {Alkyl rhamnosides, a series of amphiphilic materials exerting broad-spectrum anti-biofilm activity against pathogenic bacteria via multiple mechanisms.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {46}, number = {sup3}, pages = {S217-S232}, doi = {10.1080/21691401.2018.1491474}, pmid = {30618296}, issn = {2169-141X}, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; *Glycosides/chemical synthesis/chemistry/pharmacology ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; }, abstract = {As novel amphiphilic materials, six uncharged alkyl rhamnosides incorporating various alkyl chain and one rhamnose amine quaternary ammonium salt were successfully synthesized in this study. Their amphiphilic properties (HLB and CMC), antimicrobial and anti-biofilm activity against S. aureus and P. aeruginosa were investigated. Differentially regulated proteins and pathways were identified by comparative proteomics research to first give a sight on how alkyl rhamnosides performed the anti-biofilm activity at protein and pathway levels. Among the uncharged alkyl rhamnosides, dodecyl rhamnoside and octyl rhamnoside showed the best antimicrobial and anti-biofilm ability against S. aureus and against P. aeruginosa, respectively. Interestingly, the relationships between amphiphilic properties or MIC with anti-biofilm activity were first established. Uncharged alkyl rhamnoside with an optimized HLB value of 5.0 had both the strongest antibacterial and anti-biofilm activity against S. aureus, and MIC was the maximum biofilm inhibitory concentration for all alkyl rhamnosides. Alkyl rhamnosides have a significant overall regulatory effect on the proteomics and pathways of bacterial biofilms, including energy production, substrates transportation, signal transduction, key molecules balance, and so on. These amphiphilic materials have a great potential to be used as additives in pharmaceutic, cosmetic, food industry, hospital and in other non-medical fields.}, } @article {pmid30617866, year = {2019}, author = {Shi, C and Liu, J and Li, W and Zhao, Y and Meng, L and Xiang, M}, title = {Expression of fluconazole resistance-associated genes in biofilm from 23 clinical isolates of Candida albicans.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {50}, number = {1}, pages = {157-163}, pmid = {30617866}, issn = {1678-4405}, mesh = {Antifungal Agents/*pharmacology ; *Biofilms/drug effects ; Candida albicans/*drug effects/*genetics/isolation & purification/physiology ; China ; *Drug Resistance, Fungal ; Fluconazole/*pharmacology ; Fungal Proteins/*genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Humans ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; }, abstract = {This study aimed to establish the influence of biofilm from clinical isolates of Candida albicans on fluconazole resistance, focusing on efflux pumps and azole-targeted enzymes. Twenty-three C. albicans clinical isolates were collected from two hospitals in Shanghai, China. Antifungal susceptibility tests were performed on biofilm and planktonic cells. A crystal violet assay was used to monitor biofilm growth. Real-time RT-PCR was performed to quantify the expression of the transporter-related genes MDR1, CDR1, and CDR2 as well as ERG11, a gene encoding an enzyme targeted by antifungal drugs. Fluconazole resistance was shown to increase in biofilm in a time-dependent manner. No significant differences were observed between different strains of C. albicans. Genes encoding efflux pumps were overexpressed in early stages of biofilm formation and could also be induced by fluconazole. While ERG11 was not upregulated in biofilm, it was overexpressed upon the addition of fluconazole to biofilm and planktonic cells. Gene expression also appeared to be related to the original genotype of the strain. The upregulation of genes encoding efflux pumps demonstrates their role in the development of fluconazole resistance during the early stages of C. albicans biofilm formation.}, } @article {pmid30617242, year = {2019}, author = {Teh, WK and Dramsi, S and Tolker-Nielsen, T and Yang, L and Givskov, M}, title = {Increased Intracellular Cyclic di-AMP Levels Sensitize Streptococcus gallolyticus subsp. gallolyticus to Osmotic Stress and Reduce Biofilm Formation and Adherence on Intestinal Cells.}, journal = {Journal of bacteriology}, volume = {201}, number = {6}, pages = {}, pmid = {30617242}, issn = {1098-5530}, mesh = {3',5'-Cyclic-AMP Phosphodiesterases/deficiency/metabolism ; Animals ; *Bacterial Adhesion ; Biofilms/*growth & development ; Cell Line ; Cytosol/*chemistry ; Dinucleoside Phosphates/*analysis ; Epithelial Cells/microbiology ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Humans ; Mice ; *Osmotic Pressure ; Streptococcus gallolyticus subspecies gallolyticus/chemistry/cytology/*physiology ; }, abstract = {Cyclic di-AMP is a recently identified second messenger exploited by a number of Gram-positive bacteria to regulate important biological processes. Here, we studied the phenotypic alterations induced by the increased intracellular c-di-AMP levels in Streptococcus gallolyticus, an opportunistic pathogen responsible for septicemia and endocarditis in the elderly. We report that an S. gallolyticus c-di-AMP phosphodiesterase gdpP knockout mutant, which displays a 1.5-fold higher intracellular c-di-AMP levels than the parental strain UCN34, is more sensitive to osmotic stress and is morphologically smaller than the parental strain. Unexpectedly, we found that a higher level of c-di-AMP reduced biofilm formation of S. gallolyticus on abiotic surfaces and reduced adherence and cell aggregation on human intestinal cells. A genome-wide transcriptomic analysis indicated that c-di-AMP regulates many biological processes in S. gallolyticus, including the expression of various ABC transporters and disease-associated genes encoding bacteriocin and Pil3 pilus. Complementation of the gdpP in-frame deletion mutant with a plasmid carrying gdpP in trans from its native promoter restored bacterial morphology, tolerance to osmotic stress, biofilm formation, adherence to intestinal cells, bacteriocin production, and Pil3 pilus expression. Our results indicate that c-di-AMP is a pleiotropic signaling molecule in S. gallolyticus that may be important for S. gallolyticus pathogenesis.IMPORTANCEStreptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis in the elderly and is also strongly associated with colorectal cancer. S. gallolyticus can form biofilms, express specific pili to colonize the host tissues, and produce a specific bacteriocin allowing killing of commensal bacteria in the murine colon. Nevertheless, how the expression of these colonization factors is regulated remains largely unknown. Here, we show that c-di-AMP plays pleiotropic roles in S. gallolyticus, controlling the tolerance to osmotic stress, cell size, biofilm formation on abiotic surfaces, adherence and cell aggregation on human intestinal cells, expression of Pil3 pilus, and production of bacteriocin. This study indicates that c-di-AMP may constitute a key regulatory molecule for S. gallolyticus host colonization and pathogenesis.}, } @article {pmid30615928, year = {2019}, author = {Høiby, N and Henneberg, KÅ and Wang, H and Stavnsbjerg, C and Bjarnsholt, T and Ciofu, O and Johansen, UR and Sams, T}, title = {Formation of Pseudomonas aeruginosa inhibition zone during tobramycin disk diffusion is due to transition from planktonic to biofilm mode of growth.}, journal = {International journal of antimicrobial agents}, volume = {53}, number = {5}, pages = {564-573}, doi = {10.1016/j.ijantimicag.2018.12.015}, pmid = {30615928}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; *Disk Diffusion Antimicrobial Tests ; Microscopy ; Microscopy, Confocal ; Pseudomonas aeruginosa/*drug effects/*growth & development ; Staining and Labeling ; Time Factors ; Tobramycin/*pharmacology ; }, abstract = {Pseudomonas aeruginosa PAO1 (tobramycin MIC = 0.064 µg/mL) was used to perform agar diffusion tests employing tobramycin-containing tablets. Bacterial growth and formation of inhibition zones were studied by stereomicroscopy and by blotting with microscope slides and staining with methylene blue, Alcian blue and a fluorescent lectin for the P. aeruginosa PSL, which was studied by confocal laser scanning microscopy. Diffusion of tobramycin from the deposit was modelled using a 3D geometric version of Fick's second law of diffusion. The time-dependent gradual increase in the minimum biofilm eradication concentration (MBEC) was studied using a Calgary Biofilm Device. The early inhibition zone was visible after 5 h of incubation. The corresponding calculated tobramycin concentration at the border was 1.9 µg/mL, which increased to 3.2 µg/mL and 6.3 µg/mL after 7 h and 24 h, respectively. The inhibition zone increased to the stable final zone after 7 h of incubation. Bacterial growth and small aggregate formation (young biofilms) took place inside the inhibition zone until the small aggregates contained less than ca. 64 cells and production of polysaccharide matrix including PSL had begun; thereafter, the small bacterial aggregates were killed by tobramycin. Bacteria at the border of the stable inhibition zone and beyond continued to grow to a mature biofilm and produced large amount of polysaccharide-containing matrix. Formation of the inhibition zone during agar diffusion antimicrobial susceptibility testing is due to a switch from a planktonic to biofilm mode of growth and gives clinically important information about the increased antimicrobial tolerance of biofilms.}, } @article {pmid30615833, year = {2019}, author = {Zhang, Z and Deng, Y and Feng, K and Cai, W and Li, S and Yin, H and Xu, M and Ning, D and Qu, Y}, title = {Deterministic Assembly and Diversity Gradient Altered the Biofilm Community Performances of Bioreactors.}, journal = {Environmental science & technology}, volume = {53}, number = {3}, pages = {1315-1324}, doi = {10.1021/acs.est.8b06044}, pmid = {30615833}, issn = {1520-5851}, mesh = {Biodiversity ; Biofilms ; *Bioreactors ; *Ecosystem ; }, abstract = {Community assembly process (determinism vs stochasticity) determines the composition and diversity of a microbial community, and then shapes its functions. Understanding this complex process and its relationship to the community functions becomes a very important task for the applications of microbial biotechnology. In this study, we applied microbial electrolysis cells (MECs) with moderate species numbers and easily tractable functions as a model ecosystem, and constructed a series of biofilm communities with gradient biodiversity to examine the roles of community assembly in determining microbial community structure and functions. After stable biofilms formed, the best MEC reactor performances (e.g., gas productivity, total energy efficiency) were achieved in the group in which biofilms had the second highest α-diversity, and biofilms with even lower diversity showed declining performance. Null model analyses indicated that both deterministic and stochastic assembly played roles in the formation of biofilm communities. When deterministic assembly dominates this formation, the higher diversity of the biofilm community would generally show better reactor performance. However, when the stochasticity dominates the assembly process, the bioreactor performance would decline. This study provides novel evidence that the assembly mechanism could be one of the key processes to shift the functions, and proposes an important guidance for selecting the most efficient microorganisms for environmental biotechnologies.}, } @article {pmid30615829, year = {2019}, author = {Chen, Z and Meng, Y and Sheng, B and Zhou, Z and Jin, C and Meng, F}, title = {Linking Exoproteome Function and Structure to Anammox Biofilm Development.}, journal = {Environmental science & technology}, volume = {53}, number = {3}, pages = {1490-1500}, doi = {10.1021/acs.est.8b04397}, pmid = {30615829}, issn = {1520-5851}, mesh = {*Bacteria ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Electron, Scanning ; }, abstract = {Extracellular proteins are of paramount importance in the cell-cell interactions of anammox biofilms. However, the inherent aggregation mechanisms of anammox have largely remained elusive. Herein, using a quartz sand extraction protocol and follow-up iTRAQ-based quantitative proteomics, we identified 367 extracellular proteins from initial colonizers, mature biofilm, and detached biofilm. The extracellular proteins were mainly membrane-associated. Most of the recovered proteins (226, 72.5%) originated from the phylum Planctomycetes. In summary, 215 and 190 of the 367 proteins recovered were up- and/or downregulated at least 1.2-fold during the biofilm formation and detachment periods, respectively. These differentially expressed proteins were dominantly involved in metal ion binding, which was regarded as strong evidence for their abilities to enhance ionic bridges in extracellular polymeric substances (EPS). Scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) analysis of the biofilms further showed substantial levels of calcium and iron minerals. Critically, representative Sec-dependent secretory proteins affiliated with coccoid Planctomycetes, rod-shaped Proteobacteria, and filamentous Chloroflexi (11, 4, and 2 with differential expression, respectively) were found to have typical and abundant inner β-sheet structures, wherein hydrophobic moieties can promote anammox aggregation. Overall, these findings highlight links between differentially expressed protein functions and morphologic traits of anammox consortia during biofilm development.}, } @article {pmid30614873, year = {2020}, author = {Roy, S and Santra, S and Das, A and Dixith, S and Sinha, M and Ghatak, S and Ghosh, N and Banerjee, P and Khanna, S and Mathew-Steiner, S and Ghatak, PD and Blackstone, BN and Powell, HM and Bergdall, VK and Wozniak, DJ and Sen, CK}, title = {Staphylococcus aureus Biofilm Infection Compromises Wound Healing by Causing Deficiencies in Granulation Tissue Collagen.}, journal = {Annals of surgery}, volume = {271}, number = {6}, pages = {1174-1185}, pmid = {30614873}, issn = {1528-1140}, support = {R01 NS042617/NS/NINDS NIH HHS/United States ; R01 GM108014/GM/NIGMS NIH HHS/United States ; R01 DK114718/DK/NIDDK NIH HHS/United States ; R01 NR013898/NR/NINR NIH HHS/United States ; R01 AI061396/AI/NIAID NIH HHS/United States ; R01 GM077185/GM/NIGMS NIH HHS/United States ; R56 DK076566/DK/NIDDK NIH HHS/United States ; R01 NR015676/NR/NINR NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; R01 GM069589/GM/NIGMS NIH HHS/United States ; R01 DK076566/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Cells, Cultured ; Collagen/*metabolism ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Granulation Tissue/*metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*isolation & purification ; Swine ; Wound Healing/*physiology ; Wound Infection/diagnosis/*microbiology ; }, abstract = {OBJECTIVE: The objective of this work was to causatively link biofilm properties of bacterial infection to specific pathogenic mechanisms in wound healing.

BACKGROUND: Staphylococcus aureus is one of the four most prevalent bacterial species identified in chronic wounds. Causatively linking wound pathology to biofilm properties of bacterial infection is challenging. Thus, isogenic mutant stains of S. aureus with varying degree of biofilm formation ability was studied in an established preclinical porcine model of wound biofilm infection.

METHODS: Isogenic mutant strains of S. aureus with varying degree (ΔrexB > USA300 > ΔsarA) of biofilm-forming ability were used to infect full-thickness porcine cutaneous wounds.

RESULTS: Compared with that of ΔsarA infection, wound biofilm burden was significantly higher in response to ΔrexB or USA300 infection. Biofilm infection caused degradation of cutaneous collagen, specifically collagen 1 (Col1), with ΔrexB being most pathogenic in that regard. Biofilm infection of the wound repressed wound-edge miR-143 causing upregulation of its downstream target gene matrix metalloproteinase-2. Pathogenic rise of collagenolytic matrix metalloproteinase-2 in biofilm-infected wound-edge tissue sharply decreased collagen 1/collagen 3 ratio compromising the biomechanical properties of the repaired skin. Tensile strength of the biofilm infected skin was compromised supporting the notion that healed wounds with a history of biofilm infection are likely to recur.

CONCLUSION: This study provides maiden evidence that chronic S. aureus biofilm infection in wounds results in impaired granulation tissue collagen leading to compromised wound tissue biomechanics. Clinically, such compromise in tissue repair is likely to increase wound recidivism.}, } @article {pmid30614760, year = {2019}, author = {Sun, Y and Hu, X and Guo, D and Shi, C and Zhang, C and Peng, X and Yang, H and Xia, X}, title = {Disinfectant Resistance Profiles and Biofilm Formation Capacity of Escherichia coli Isolated from Retail Chicken.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {5}, pages = {703-711}, doi = {10.1089/mdr.2018.0175}, pmid = {30614760}, issn = {1931-8448}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Benzalkonium Compounds/pharmacology ; Biofilms/*drug effects/growth & development ; Cetrimonium/pharmacology ; Cetylpyridinium/pharmacology ; Chickens ; Chlorhexidine/pharmacology ; Disinfectants/*pharmacology ; Drug Resistance, Bacterial ; Escherichia coli/*drug effects/genetics/growth & development ; Food Contamination/analysis ; *Genes, Bacterial ; Humans ; Meat Products/*microbiology ; Microbial Sensitivity Tests ; Triclosan/pharmacology ; }, abstract = {Disinfectant resistance and biofilm formation capacity are two important characteristics that contribute to the persistence of microorganisms in food processing environments and contamination of food products. This study investigated the susceptibility of 510 Escherichia coli isolates against 5 disinfectants and the prevalence of 10 disinfectant-resistant genes in these isolates. The biofilm formation capacity of 194 isolates was determined, and the correlation between disinfectant resistance and biofilm formation was analyzed. The minimal inhibitory concentrations (MICs) of cetyltrimethylammonium bromide (CTAB), benzalkonium chloride (BC), cetylpyridinium chloride, and chlorhexidine (CHX) against isolates were 32-512, 16-256, 32-256, and 2-32 mg/L, respectively. The MICs of triclosan against 88.43% of isolates were 8-1,024 mg/L, while the MICs for the rest of isolates exceed 2,048 mg/L. The presence of ydgE, ydgF, and qacF genes was significantly correlated with the CHX resistance of E. coli isolates, while the presence of qacF and qacEΔ1 genes was significantly correlated with CTAB and BC resistance, respectively. The biofilm formation capacity (adjusted optical density value) was positively correlated with BC resistance (r = 0.201, p < 0.01) and showed no correlation with other disinfectants. The presence of sugE(p) was positively correlated with biofilm formation, while four genes were negatively correlated with biofilm formation. This study provides useful data on disinfectant resistance and biofilm formation capacity of E. coli contaminating poultry products, which could be helpful in guiding proper disinfectant usage and establishing effective biofilm eradication strategy in food industry.}, } @article {pmid30614685, year = {2019}, author = {Zhu, N and Wang, S and Tang, C and Duan, P and Yao, L and Tang, J and Wong, PK and An, T and Dionysiou, DD and Wu, Y}, title = {Protection Mechanisms of Periphytic Biofilm to Photocatalytic Nanoparticle Exposure.}, journal = {Environmental science & technology}, volume = {53}, number = {3}, pages = {1585-1594}, doi = {10.1021/acs.est.8b04923}, pmid = {30614685}, issn = {1520-5851}, mesh = {*Biofilms ; Biomass ; Chlorophyll ; *Nanoparticles ; }, abstract = {Researchers are devoting great effort to combine photocatalytic nanoparticles (PNPs) with biological processes to create efficient environmental purification technologies (i.e., intimately coupled photobiocatalysis). However, little information is available to illuminate the responses of multispecies microbial aggregates against PNP exposure. Periphytic biofilm, as a model multispecies microbial aggregate, was exposed to three different PNPs (CdS, TiO2, and Fe2O3) under xenon lamp irradiation. There were no obvious toxic effects of PNP exposure on periphytic biofilm as biomass, chlorophyll content, and ATPase activity were not negatively impacted. Enhanced production of extracellular polymetric substances (EPS) is the most important protection mechanism of periphytic biofilm against PNPs exposure. Although PNP exposure produced extracellular superoxide radicals and caused intracellular reactive oxygen species (ROS) accumulation in periphytic biofilm, the interaction between EPS and PNPs could mitigate production of ROS while superoxide dismutase could alleviate biotic ROS accumulation in periphytic biofilm. The periphytic biofilms changed their community composition in the presence of PNPs by increasing the relative abundance of phototrophic and high nutrient metabolic microorganisms (families Chlamydomonadaceae, Cyanobacteriacea, Sphingobacteriales, and Xanthomonadaceae). This study provides insight into the protection mechanisms of microbial aggregates against simultaneous photogenerated and nanoparticle toxicity from PNPs.}, } @article {pmid30614293, year = {2018}, author = {Jarząb, N and Walczak, M and Smoliński, D and Sionkowska, A}, title = {The impact of medicinal brines on microbial biofilm formation on inhalation equipment surfaces.}, journal = {Biofouling}, volume = {34}, number = {9}, pages = {963-975}, doi = {10.1080/08927014.2018.1515353}, pmid = {30614293}, issn = {1029-2454}, mesh = {Biofilms/*drug effects/growth & development ; Equipment Contamination/prevention & control ; Equipment and Supplies/*microbiology ; Gram-Negative Bacteria/*isolation & purification ; Gram-Positive Bacteria/*isolation & purification ; Humans ; Polyethylene ; Polypropylenes ; Polyvinyl Chloride ; Respiratory Therapy/*instrumentation ; Sodium Chloride/*pharmacology ; Surface Properties ; }, abstract = {Materials such as polyvinyl chloride, polypropylene, and polyethylene are used for the construction of medical equipment, including inhalation equipment. Inhalation equipment, because of the wet conditions and good oxygenation, constitutes a perfect environment for microbial biofilm formation. Biofilms may affect microbiological cleanliness of inhalation facilities and installations and promote the development of pathogenic bacteria. Microbial biofilms can form even in saline environments. Therefore, the aim of this study was to evaluate the effect of medicinal brines on microbial biofilm formation on the surfaces of inhalation equipment. The study confirmed the high risk of biofilm formation on surfaces used in inhalation equipment. Isolated microorganisms belonged to potential pathogens of the respiratory system, which can pose a health threat to hospital patients. The introduction of additional contaminants increased the amount of bacterial biofilm. On the other hand, the presence of brines significantly limited the amount of biofilm, thus eliminating the risk of infections.}, } @article {pmid30612440, year = {2019}, author = {Tailly, T and Van Haute, C}, title = {Editorial on: In Vitro Effects of a Novel Coating Agent on Bacterial Biofilm Development on Ureteral Stents by Szell et al. (From: Szell T, Dressler FF, Goelz H, et al. J Endourol 2019;33:225-231; DOI: 10.1089/end.2018.0616).}, journal = {Journal of endourology}, volume = {33}, number = {3}, pages = {232-233}, doi = {10.1089/end.2018.0907}, pmid = {30612440}, issn = {1557-900X}, mesh = {Biofilms ; Stents ; *Ureter ; }, } @article {pmid30612353, year = {2019}, author = {Masmoudi Jabri, K and Fiedler, T and Saidi, A and Nolde, E and Ogurek, M and Geissen, SU and Bousselmi, L}, title = {Steady-state modeling of the biodegradation performance of a multistage moving bed biofilm reactor (MBBR) used for on-site greywater treatment.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {19}, pages = {19047-19062}, pmid = {30612353}, issn = {1614-7499}, mesh = {Ammonia/chemistry ; Biodegradation, Environmental ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Nitrogen/chemistry ; *Sewage ; Water Purification/*methods ; }, abstract = {In this study, the Activated Sludge Model No. 3 (ASM3) was applied for the simulation of the removal of organics and nitrogen in a multistage moving bed biofilm reactor (MBBR) used for biological greywater treatment. The data related to the characterization of the greywater were collected over a period of 5 months to be investigated in the model. The reactor showed a high performance for the removal of chemical oxygen demand (COD), dissolved organic carbon (DOC), biological oxygen demand (BOD5), ammonia (NH4-N), and total nitrogen (TN) with a removal efficiency of 93%, 80.7%, 99%, 89%, and 77%, respectively. The results of modeling showed a good correlation between simulated and experimental concentrations of COD issued from different reactors of the MBBR system. The adaptability of the ASM3 model to fit other parameters such as TN, NH4-N, total suspended solids (TSS), and the dissolved oxygen (DO) was also investigated for two selected reactors: reactor (R1) and the reactor (R5). The simulation results showed an acceptable correlation regarding the evolution of the investigated parameters in R1 and R5 and in the effluent except for total nitrogen TN. The adjustment of the stoichiometric parameters led to a satisfactory simulation of TN concentrations.}, } @article {pmid30610246, year = {2019}, author = {Polak, D and Shany-Kdoshim, S and Zaydel, L and Feuerstein, O and Houri-Haddad, Y}, title = {High-resolution novel method for tracking bacteria in a multi-species biofilm.}, journal = {Archives of microbiology}, volume = {201}, number = {2}, pages = {259-266}, doi = {10.1007/s00203-018-1614-z}, pmid = {30610246}, issn = {1432-072X}, mesh = {Actinomyces/isolation & purification ; Bacteria/*isolation & purification ; *Biofilms ; *Flow Cytometry ; Fusobacterium nucleatum/isolation & purification ; Porphyromonas gingivalis/isolation & purification ; Streptococcus sanguis/isolation & purification ; }, abstract = {The aim of this study is to establish a novel high resolution tracking ability of a specific bacterium in multispecies biofilm. A periodontal multispecies biofilm was constructed with Streptococcus sanguis, Actinomyces naeslundii, Porphyromonas gingivalis and Fusobacterium nucleatum. A single species was stained with fluorescein isothiocyanate (FITC). The mature biofilm was stained for viability (propidium iodide) and analysis was performed with flow cytometry. The sensitivity of the assay was compared with colony forming units (CFU) counts. A single cell suspension of P. gingivalis was grown in broth and biofilm to identify the location of these events on side scatter and forward scatter. The sensitivity of the assay was comparable to that of the CFU counts. The assay allows quantification of the ratio of a single bacterium within the biofilm, and its viable proportion. The described method is reproducible and of high resolution, and allows the examination of microbes' composition and viability within a biofilm structure.}, } @article {pmid30609710, year = {2019}, author = {Zurob, E and Dennett, G and Gentil, D and Montero-Silva, F and Gerber, U and Naulín, P and Gómez, A and Fuentes, R and Lascano, S and Rodrigues da Cunha, TH and Ramírez, C and Henríquez, R and Del Campo, V and Barrera, N and Wilkens, M and Parra, C}, title = {Inhibition of Wild Enterobacter cloacae Biofilm Formation by Nanostructured Graphene- and Hexagonal Boron Nitride-Coated Surfaces.}, journal = {Nanomaterials (Basel, Switzerland)}, volume = {9}, number = {1}, pages = {}, pmid = {30609710}, issn = {2079-4991}, support = {ID15I10576//FONDEF/ ; PIM_USM_12_18//Proyecto Interno Multidisciplinario/ ; 3160568//Fondecyt Postdoctoral/ ; P10-035F//Millennium Science Initiative/ ; }, abstract = {Although biofilm formation is a very effective mechanism to sustain bacterial life, it is detrimental in medical and industrial sectors. Current strategies to control biofilm proliferation are typically based on biocides, which exhibit a negative environmental impact. In the search for environmentally friendly solutions, nanotechnology opens the possibility to control the interaction between biological systems and colonized surfaces by introducing nanostructured coatings that have the potential to affect bacterial adhesion by modifying surface properties at the same scale. In this work, we present a study on the performance of graphene and hexagonal boron nitride coatings (h-BN) to reduce biofilm formation. In contraposition to planktonic state, we focused on evaluating the efficiency of graphene and h-BN at the irreversible stage of biofilm formation, where most of the biocide solutions have a poor performance. A wild Enterobacter cloacae strain was isolated, from fouling found in a natural environment, and used in these experiments. According to our results, graphene and h-BN coatings modify surface energy and electrostatic interactions with biological systems. This nanoscale modification determines a significant reduction in biofilm formation at its irreversible stage. No bactericidal effects were found, suggesting both coatings offer a biocompatible solution for biofilm and fouling control in a wide range of applications.}, } @article {pmid30608101, year = {2019}, author = {Chen, M and Wei, J and Xie, S and Tao, X and Zhang, Z and Ran, P and Li, X}, title = {Bacterial biofilm destruction by size/surface charge-adaptive micelles.}, journal = {Nanoscale}, volume = {11}, number = {3}, pages = {1410-1422}, doi = {10.1039/c8nr05575k}, pmid = {30608101}, issn = {2040-3372}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Azithromycin/*chemistry/pharmacology ; Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Drug Carriers/chemistry/toxicity ; Erythrocytes/cytology/drug effects/metabolism ; Female ; Hemolysis/drug effects ; Humans ; Hydrogen-Ion Concentration ; Mice ; *Micelles ; Polymers/chemistry ; Pseudomonas aeruginosa/*physiology ; Rats ; Rats, Wistar ; Static Electricity ; Tyrosine/chemistry ; }, abstract = {Biofilms formed by pathogenic bacteria are one of the most important reasons for multidrug resistance. One of the major limitations in the biofilm treatment is the existence of intensive matrices, which greatly block the diffusion of antimicrobial agents. In the current study, we designed poly(aspartamide)-derived micelles self-assembled from cationic copolymers with azithromycin-conjugated and pH-sensitive copolymers, followed by loading cis-aconityl-d-tyrosine (CA-Tyr) via electrostatic interactions. In response to the acidic microenvironment of the biofilm matrix, the hydrophilic transition of the pH-sensitive copolymers and the removal of CA-Tyr led to a sharp decrease in micelle size from 107 nm to 54 nm and a rapid shift in their zeta potential from -11.7 mV to +26.4 mV, which facilitated the penetration of the micelles into biofilms. The acid-labile release of d-tyrosine disintegrated the biofilm matrix, and the lipase-triggered release of azithromycin eradicated the bacteria in the biofilms. An in vitro test was performed on pre-established P. aeruginosa biofilms in microwells, while biofilms grown on catheters were surgically implanted in rats for in vivo evaluation. The results demonstrated the capabilities of the size/surface charge-adaptive micelles in the intensive infiltration in the biofilm matrix and spatiotemporal release of biofilm dispersion and antibacterial agents for the comprehensive treatment of biofilm-relevant infections.}, } @article {pmid30607721, year = {2019}, author = {Hendiani, S and Pornour, M and Kashef, N}, title = {Sub-lethal antimicrobial photodynamic inactivation: an in vitro study on quorum sensing-controlled gene expression of Pseudomonas aeruginosa biofilm formation.}, journal = {Lasers in medical science}, volume = {34}, number = {6}, pages = {1159-1165}, pmid = {30607721}, issn = {1435-604X}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Bacterial ; Methylene Blue/pharmacology ; Microbial Viability/drug effects ; *Photochemotherapy ; Pseudomonas aeruginosa/drug effects/*genetics/*physiology/ultrastructure ; Quorum Sensing/*drug effects ; }, abstract = {During antimicrobial photodynamic inactivation (APDI) in the treatment of an infection, it is likely that microorganisms would be exposed to sub-lethal doses of APDI (sAPDI). Although sAPDI cannot kill microorganisms, it can significantly affect microbial virulence. In this study, we evaluated the effect of sAPDI using methylene blue (MB) on the expression of genes belonging to two quorum sensing (QS) operons (rhl and las systems) and two genes necessary for biofilm formation (pelF and pslA) under QS control in Pseudomonas aeruginosa. Biofilm formation ability of P. aeruginosa ATCC 27853 exposed to sAPDI (MB at 0.012 mM and light dose of 23 J/cm[2]) was evaluated using triphenyl tetrazolium chloride (TTC) assay and scanning electron microscopy (SEM). The effect of sAPDI on expression of rhlI, rhlR, lasI, lasR, pelF, and pslA were also evaluated by quantitative real-time polymerase chain reaction. Quantitative assay (TTC) results and morphological observations (SEM) indicated that a single sAPDI treatment resulted in a significant decrease in biofilm formation ability of P. aeruginosa ATCC 27853 compared to their non-treated controls (P = 0.012). These results were consistent with the expression of genes belonging to rhl and las systems and pelF and pslA genes. The results suggested that the transcriptional decreases caused by MB-sAPDI did lead to phenotypic changes.}, } @article {pmid30606691, year = {2019}, author = {Jin, Z and Jiang, Q and Fang, B and Sun, B}, title = {The ArlR-MgrA regulatory cascade regulates PIA-dependent and protein-mediated biofilm formation in Rbf-dependent and Rbf-independent pathways.}, journal = {International journal of medical microbiology : IJMM}, volume = {309}, number = {2}, pages = {85-96}, doi = {10.1016/j.ijmm.2018.12.006}, pmid = {30606691}, issn = {1618-0607}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/metabolism ; *Gene Expression Regulation, Bacterial ; *Genes, Regulator ; Polysaccharides, Bacterial/*metabolism ; Promoter Regions, Genetic ; Protein Binding ; Staphylococcus aureus/genetics/*growth & development ; }, abstract = {The two-component system response regulator ArlR and the global regulator MgrA in Staphylococcus aureus participated in numerous biological processes including biofilm formation inhibition. Previous studies have shown that these two regulators could function as a regulatory cascade. Rbf is a positive regulator of biofilm formation enhancing the production of PIA (polysaccharide intercellular adhesin). Here we have demonstrated that both ArlR and MgrA can directly bind to the promoter of rbf and repress its expression. ArlR and MgrA can also directly bind to the promoter of ica operon and enhance the expression of icaA and PIA production, revealing that the ArlR-MgrA regulatory cascade controls PIA-dependent biofilm formation. In addition, we have found that Rbf can directly bind to the aur promoter and repress the expression of aur, which encodes a protease initiating a protease cascade to inhibit protein-mediated biofilm formation. Moreover, our data indicate that the ArlR-MgrA regulatory cascade can promote the expression of aur by directly binding to its promoter and inhibit protein-mediated biofilm formation. These findings shed light on the molecular mechanisms of both PIA-dependent and protein-mediated biofilm formation modulated by the ArlR-MgrA regulatory cascade and the new role of Rbf in protein-mediated biofilm formation, and broaden our understanding of the biofilm formation regulation in S. aureus.}, } @article {pmid30605272, year = {2018}, author = {Bino, E and Lauková, A and Kandričáková, A and Nemcová, R}, title = {Assessment of biofilm formation by faecal strains of Enterococcus hirae from different species of animals.}, journal = {Polish journal of veterinary sciences}, volume = {21}, number = {4}, pages = {747-754}, doi = {10.24425/124314}, pmid = {30605272}, issn = {1505-1773}, mesh = {Animals ; Biofilms/*growth & development ; Enterococcus hirae/*physiology ; Feces/*microbiology ; Species Specificity ; }, abstract = {Enterococcus hirae belongs in the Enterococcus faecium group within the genus Enterococcus. This species occurs naturally in the environment, commensally in the alimentary tracts of animals, and pathologically for example in humans with urinary infections. Some strains of E. hirae possess virulence factors, including biofilm formation. Biofilm growth protects bacteria against host de- fences; biofilm can be a source of persistent infection. Testing bacterial strains for their ability to form biofilm might therefore facilitate their treatment or prevention. This study focuses on bio- film formation by E. hirae strains derived from various animals. This kind of testing has never been done before. A total of 64 identified E. hirae from laying hens, ducks, pheasants, ostriches, rabbits, horses and a goat were tested by means of three methods; using Congo red agar, the tube method and microtiter plate agar. The majority of strains were found to form biofilm. 62.5% of strains were biofilm-forming, four categorized as highly positive (OD570 ≥1); most strains were low-grade biofilm positive (0.1 ≤ OD 570 ⟨ 1). Related to poultry, 55 E. hirae strains were tested and found to produce biofilm; 24 strains did not form biofilm, 31 strains were biofilm-forming; 27 strains showed low-grade biofilm formation, and four strains were highly biofilm-forming. Four strains from hens and ostriches reached the highest OD570 values, more than 0.500. Rabbit-de- rived E. hirae strains as well as strains isolated from horses and the goat were low-grade bio- film-forming. Microtiter plate assay proved to be the best tool for testing the in vitro biofilm for- mation capacity of E. hirae strains from different species of animals.}, } @article {pmid30602527, year = {2019}, author = {Dominguez, EG and Zarnowski, R and Choy, HL and Zhao, M and Sanchez, H and Nett, JE and Andes, DR}, title = {Conserved Role for Biofilm Matrix Polysaccharides in Candida auris Drug Resistance.}, journal = {mSphere}, volume = {4}, number = {1}, pages = {}, pmid = {30602527}, issn = {2379-5042}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms ; Candida/*drug effects/growth & development ; *Drug Resistance, Fungal ; Drug Tolerance ; Extracellular Polymeric Substance Matrix/*drug effects ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Candida auris has emerged as an outbreak pathogen associated with high mortality. Biofilm formation and linked drug resistance are common among Candida species. Drug sequestration by the biofilm matrix accounts for much of the antifungal tolerance. In this study, we examine the biofilm matrix composition and function for a diverse set of C. auris isolates. We show that matrix sequesters nearly 70% of the available triazole antifungal. Like the biofilms formed by other Candida spp., we find that the matrix of C. auris is rich in mannan-glucan polysaccharides and demonstrate that their hydrolysis reduces drug tolerance. This biofilm matrix resistance mechanism appears conserved among Candida species, including C. aurisIMPORTANCECandida auris is an emerging fungal threat linked to poor patient outcomes. The factors responsible for this apparent increase in pathogenicity remain largely unknown. Biofilm formation has been suggested as an important factor for persistence of this organism in patients and the environment. Our findings reveal one mechanism utilized by C. auris to evade the effect of triazole antifungal therapy during biofilm growth. The conservation of the protective biofilm matrix among Candida spp. suggests that is a promising pan-fungal Candida biofilm drug target.}, } @article {pmid30601473, year = {2019}, author = {Liu, Y and Shi, L and Su, L and van der Mei, HC and Jutte, PC and Ren, Y and Busscher, HJ}, title = {Nanotechnology-based antimicrobials and delivery systems for biofilm-infection control.}, journal = {Chemical Society reviews}, volume = {48}, number = {2}, pages = {428-446}, doi = {10.1039/c7cs00807d}, pmid = {30601473}, issn = {1460-4744}, mesh = {Anti-Infective Agents/chemistry/*pharmacology/therapeutic use ; Bacterial Infections/drug therapy ; Biofilms/*drug effects ; Drug Carriers/*chemistry ; Drug Resistance, Bacterial/drug effects ; Gram-Negative Bacteria/drug effects/physiology ; Gram-Positive Bacteria/drug effects/physiology ; Humans ; Nanoparticles/chemistry ; Nanotechnology/*methods ; }, abstract = {Bacterial-infections are mostly due to bacteria in an adhering, biofilm-mode of growth and not due to planktonically growing, suspended-bacteria. Biofilm-bacteria are much more recalcitrant to conventional antimicrobials than planktonic-bacteria due to (1) emergence of new properties of biofilm-bacteria that cannot be predicted on the basis of planktonic properties, (2) low penetration and accumulation of antimicrobials in a biofilm, (3) disabling of antimicrobials due to acidic and anaerobic conditions prevailing in a biofilm, and (4) enzymatic modification or inactivation of antimicrobials by biofilm inhabitants. In recent years, new nanotechnology-based antimicrobials have been designed to kill planktonic, antibiotic-resistant bacteria, but additional requirements rather than the mere killing of suspended bacteria must be met to combat biofilm-infections. The requirements and merits of nanotechnology-based antimicrobials for the control of biofilm-infection form the focus of this Tutorial Review.}, } @article {pmid30600090, year = {2019}, author = {Feng, J and Cheng, L and Zhou, X and Xu, HHK and Weir, MD and Li, Q and Hannig, M and Rupf, S}, title = {Effects of water aging on the mechanical and anti-biofilm properties of glass-ionomer cement containing dimethylaminododecyl methacrylate.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {3}, pages = {434-443}, doi = {10.1016/j.dental.2018.12.003}, pmid = {30600090}, issn = {1879-0097}, mesh = {Biofilms ; *Glass Ionomer Cements ; Humans ; Materials Testing ; Methacrylates ; Quaternary Ammonium Compounds ; Surface Properties ; *Water ; }, abstract = {OBJECTIVES: The aims of this study were to investigate the effects of water aging for up to 6months on the mechanical and anti-biofilm properties of a novel antibacterial glass ionomer cement (GIC) containing dimethylaminododecyl methacrylate (DMADDM).

METHODS: GIC specimens (n=180) which contained DMADDM (0wt.%, 1.1wt.% or 2.2wt.%) were prepared. The mechanical properties surface roughness, microhardness and the surface charge density of ammonium groups were measured before and after water aging for 3 and 6months at 37°C. Further six months aged specimens (n=216) were worn by 6 volunteers in their oral cavities for 24h and 72h. Biofilm formation was analyzed and rated by fluorescence microscopy (FM) and by scanning electron microscopy (SEM). Biofilm viability was analyzed by FM.

RESULTS: Water aging did not show any adverse effects on the surface roughness and hardness of the material. The surface charge density of the GIC samples containing DMADDM decreased due to the aging procedure, however, was still higher than that of the GIC without DMADDM. In situ biofilm formation was significantly reduced after 24h on DMADDM containing GIC (p<0.05). FM results showed a higher ratio of red/green fluorescence on GIC-DMADDM samples.

SIGNIFICANCE: Incorporating DMADDM into GIC affected the material properties in a tolerable manner even after 6months of storage in water. The new GIC is a promising material to affect the biofilm formation on the surface of restorations.}, } @article {pmid30599353, year = {2019}, author = {Gambino, M and Sanmartín, P and Longoni, M and Villa, F and Mitchell, R and Cappitelli, F}, title = {Surface colour: An overlooked aspect in the study of cyanobacterial biofilm formation.}, journal = {The Science of the total environment}, volume = {659}, number = {}, pages = {342-353}, doi = {10.1016/j.scitotenv.2018.12.358}, pmid = {30599353}, issn = {1879-1026}, mesh = {*Air Microbiology ; Biofilms/*growth & development ; *Biomass ; Color ; Cyanobacteria/*physiology ; Pigments, Biological/*physiology ; }, abstract = {Cyanobacteria can grow as biofilms, communities that colonize surfaces and that play a fundamental role in the ecology of many diverse habitats and in the conversion of industrial production to green platforms. Although biofilm growth is known to be significantly affected by several characteristics, the effect of colour surface is an overlooked aspect that has not yet been investigated. In this study, we describe the effect of colour hues (white, red, blue and black) on the growth of cyanobacterial biofilms on air-exposed substrates. We measured growth, architecture, pigment production and levels of ATP and reactive oxygen species in cyanobacterial biofilms formed on different coloured substrates. The study findings demonstrate, for the first time, that the colour of a surface affects biofilm formation at the air-solid interface (with more biomass accumulating on white and red substrates than on blue and black substrates) and also alters the biofilm architecture. In addition, the roles of chromatic adaptation, phototrophic cells and reactive oxygen species as intermediates between colour sensing and biofilm response are discussed. Our results support the importance of colour as a new factor that favours surface colonization by cyanobacteria and its contribution to biofilm formation.}, } @article {pmid30599165, year = {2019}, author = {Li, Y and Hu, X and Ruan, J and Arola, DD and Ji, C and Weir, MD and Oates, TW and Chang, X and Zhang, K and Xu, HHK}, title = {Bonding durability, antibacterial activity and biofilm pH of novel adhesive containing antibacterial monomer and nanoparticles of amorphous calcium phosphate.}, journal = {Journal of dentistry}, volume = {81}, number = {}, pages = {91-101}, doi = {10.1016/j.jdent.2018.12.013}, pmid = {30599165}, issn = {1879-176X}, mesh = {*Anti-Bacterial Agents ; Biofilms ; *Calcium Phosphates ; *Dental Cements ; Hydrogen-Ion Concentration ; Materials Testing ; Methacrylates ; *Nanoparticles ; }, abstract = {OBJECTIVES: The dentin bonding often fails over time, leading to secondary caries and restoration failure. The objectives of this study were to develop an adhesive with dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP), and investigate the effects of storage in artificial saliva for six months on the bonding durability, antibacterial activity, ion release and biofilm pH properties for the first time.

METHODS: DMAHDM was added at 5% (by mass) to Scotchbond Primer and Adhesive (SBMP). NACP was added at 10%, 20%, and 30% to SBMP adhesive. Dentin bonding durability, antibacterial activity against Streptococcus mutans biofilms, and calcium (Ca) and phosphate (P) ion liberation properties were investigated after 1 day and 6months of storage in artificial saliva.

RESULTS: Dentin bond strength (n = 50) had 25% loss after 6 months of aging for SBMP control. However, SBMP + DMAHDM+10NACP and SBMP + DMAHDM+20NACP showed no loss in bond strength after storage in artificial saliva for 6 months. The DMAHDM + NACP incorporation method dramatically reduced the biofilm metabolic activity and acid production, and decreased the biofilm CFU by four orders of magnitude, compared to SBMP control, even after 6 months of aging (p < 0.05). DMAHDM + NACP had long-lasting Ca and P ion releases, and raised the biofilm pH to 6.8, while the control group had a cariogenic biofilm pH of 4.5.

CONCLUSIONS: Incorporating DMAHDM + NACP in bonding agent yielded potent and long-lasting antibacterial activity and ions liberation ability, and much higher long-term dentin bond strength after 6-month of aging. The new bonding agent is promising to inhibit caries at the restoration margins and increase the resin-dentin bonding longevity.

CLINICAL SIGNIFICANCE: The novel bioactive adhesive is promising to protect tooth structures from biofilm acids and secondary caries. NACP and DMAHDM have great potential for applications to a wide range of dental materials to reduce plaque and achieve therapeutic effects.}, } @article {pmid30597714, year = {2019}, author = {Zancan, RF and Calefi, PHS and Borges, MMB and Lopes, MRM and de Andrade, FB and Vivan, RR and Duarte, MAH}, title = {Antimicrobial activity of intracanal medications against both Enterococcus faecalis and Candida albicans biofilm.}, journal = {Microscopy research and technique}, volume = {82}, number = {5}, pages = {494-500}, doi = {10.1002/jemt.23192}, pmid = {30597714}, issn = {1097-0029}, support = {2016/25133-1//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Candidiasis/*drug therapy ; Cattle ; Enterococcus faecalis/drug effects ; Gram-Positive Bacterial Infections/*drug therapy ; Image Processing, Computer-Assisted ; Incisor ; Microscopy, Confocal ; Models, Theoretical ; Root Canal Therapy/*methods ; Stomatognathic Diseases/*drug therapy ; Treatment Outcome ; }, abstract = {Enterococcus faecalis and Candida albicans have been associated with cases of secondary and persistent root canal infections, been resistant to calcium hydroxide. So, the evaluation of the susceptibility of these microorganisms biofilms to new drugs is an important practice for establishing the best drug and consequently success of treatment. For this, in vitro biofilm formation of E. faecalis and C. albicans was induced separately on blocks obtained from bovine teeth. After the period of specimen incubation for biofilm maturation, the samples were immersed in the pastes: 1 - calcium hydroxide (CH), 2 - chlorhexidine (C), 3 - ciprofloxacin (CP), 4 - metronidazole (MT), 5 - ketoconazole (KE), 6 - double antibiotic (DB), 7 - triple antibiotic (TA), 8 - ciprofloxacin + ketoconazole (CPKE); 9 - ciprofloxacin + metronidazole + ketoconazole (CPMTKE), 10 - metronidazole + ketoconazole (MTKE), and 11 - control (CO) for 7 days. Next, the specimens were live/dead stained for analysis by confocal microscopy. By means of the Bioimage program, the biovolume and percentage of live cells were measured. The data were statistically compared (p = .05). For the C. albicans biofilm, the best antimicrobial action was found for MTKE, CPKE, and MT groups. Whereas for E. faecalis biofilm, the lowest percentage of live bacteria was found in TA, DB, and CP groups; however, KE, CPKE, CPMTKE, and MTKE groups shown to be effective. The authors concluded calcium hydroxide paste and chlorhexidine was not effective for both biofilms. The MTKE and CPKE pastes presented effectiveness for both biofilms. TA and DB pastes were effective just in the E. faecalis biofilms.}, } @article {pmid30596498, year = {2019}, author = {Sun, L and Jiang, W and Zhang, H and Guo, Y and Chen, W and Jin, Y and Chen, H and Du, K and Dai, H and Ji, J and Wang, B}, title = {Photosensitizer-Loaded Multifunctional Chitosan Nanoparticles for Simultaneous in Situ Imaging, Highly Efficient Bacterial Biofilm Eradication, and Tumor Ablation.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {2}, pages = {2302-2316}, doi = {10.1021/acsami.8b19522}, pmid = {30596498}, issn = {1944-8252}, mesh = {Animals ; Bacteria/*growth & development ; Bacterial Infections/*drug therapy/metabolism/pathology ; *Bacterial Physiological Phenomena/drug effects/radiation effects ; *Biofilms/drug effects/growth & development/radiation effects ; Cell Line, Tumor ; Chitosan/*analogs & derivatives/chemistry/pharmacology ; Humans ; Mice ; Mice, Nude ; *Nanoparticles/chemistry/therapeutic use ; Neoplasms, Experimental/*drug therapy/metabolism/pathology ; *Photochemotherapy ; *Photosensitizing Agents/chemistry/pharmacology ; Rabbits ; Xenograft Model Antitumor Assays ; }, abstract = {In recent decades, bacterial and viral infections and chronic inflammatory response have emerged as important causes of cancer. Also, infections remain a significant cause of morbidity and mortality in cancer patients. In this work, carboxymethyl chitosan nanoparticles (CMC NPs) were synthesized in a facile and green way and further combined with ammonium methylbenzene blue (MB) as a cross-linking agent as well as a fluorescent molecule and a photosensitizer for self-imaging photodynamic therapy (PDT). The obtained CMC-MB NPs exhibited an apparent pH-responsive release behavior of MB, which was released for a prolonged period in a simulated physiological environment (pH 7.4) for more than 15 days and the time reduced to only 3.5 h in acidic conditions (pH 5.5). When irradiated by a 650 nm laser at 202 mW/cm[2] for 5 min, the CMC-MB NPs showed efficient bactericidal and biofilm eradication properties as well as suppression of tumor cell growth in a similar acidified microenvironment. Furthermore, in an in vivo rabbit wound bacterial infection model, the rapid sterilization of CMC-MB NPs played a crucial role in bacterial infections, inflammation inhibition, and wound healing. As a PDT treatment against cancer, the CMC-MB NPs also exhibited an efficient antitumor therapeutic effect in a subcutaneous tumor mice model.}, } @article {pmid30595694, year = {2018}, author = {Areid, N and Söderling, E and Tanner, J and Kangasniemi, I and Närhi, TO}, title = {Early Biofilm Formation on UV Light Activated Nanoporous TiO2 Surfaces In Vivo.}, journal = {International journal of biomaterials}, volume = {2018}, number = {}, pages = {7275617}, pmid = {30595694}, issn = {1687-8787}, abstract = {PURPOSE: To explore early S. mutans biofilm formation on hydrothermally induced nanoporous TiO2 surfaces in vivo and to examine the effect of UV light activation on the biofilm development.

MATERIALS AND METHODS: Ti-6Al-4V titanium alloy discs (n = 40) were divided into four groups with different surface treatments: noncoated titanium alloy (NC); UV treated noncoated titanium alloy (UVNC); hydrothermally induced TiO2 coating (HT); and UV treated titanium alloy with hydrothermally induced TiO2 coating (UVHT). In vivo plaque formation was studied in 10 healthy, nonsmoking adult volunteers. Titanium discs were randomly distributed among the maxillary first and second molars. UV treatment was administered for 60 min immediately before attaching the discs in subjects' molars. Plaque samples were collected 24h after the attachment of the specimens. Mutans streptococci (MS), non-mutans streptococci, and total facultative bacteria were cultured, and colonies were counted.

RESULTS: The plaque samples of NC (NC + UVNC) surfaces showed over 2 times more often S. mutans when compared to TiO2 surfaces (HT + UVHT), with the number of colonized surfaces equal to 7 and 3, respectively.

CONCLUSION: This in vivo study suggested that HT TiO2 surfaces, which we earlier showed to improve blood coagulation and encourage human gingival fibroblast attachment in vitro, do not enhance salivary microbial (mostly mutans streptococci) adhesion and initial biofilm formation when compared with noncoated titanium alloy. UV light treatment provided Ti-6Al-4V surfaces with antibacterial properties and showed a trend towards less biofilm formation when compared with non-UV treated titanium surfaces.}, } @article {pmid30595445, year = {2019}, author = {Khan, FAK and Kaduskar, RN and Patil, R and Patil, RH and Ansari, SA and Alkahtani, HM and Almehizia, AA and Shinde, DB and Sangshetti, JN}, title = {Synthesis, biological evaluations and computational studies of N-(3-(-2-(7-Chloroquinolin-2-yl)vinyl) benzylidene)anilines as fungal biofilm inhibitors.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {29}, number = {4}, pages = {623-630}, doi = {10.1016/j.bmcl.2018.12.046}, pmid = {30595445}, issn = {1464-3405}, mesh = {Aniline Compounds/chemistry ; Anti-Bacterial Agents/pharmacology ; Antifungal Agents/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Candida albicans/*drug effects/metabolism ; Microbial Sensitivity Tests ; Quinolines/*chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {In the present investigation, new chloroquinoline derivatives bearing vinyl benzylidene aniline substituents at 2nd position were synthesized and screed for biofilm inhibitory, antifungal and antibacterial activity. The result of biofilm inhibition of C. albicans suggested that compounds 5j (IC50 value = 51.2 μM) and 5a (IC50 value = 66.2 μM) possess promising antibiofilm inhibition when compared with the standard antifungal drug fluconazole (IC50 = 40.0 μM). Two compounds 5a (MIC = 94.2 μg/mL) and 5f (MIC = 98.8 μg/mL) also exhibited good antifungal activity comparable to standard drug fluconazole (MIC = 50.0 μg/mL). The antibacterial screening against four strains of bacteria viz. E. coli, P. aeruginosa, B. subtilis, and S. aureus suggested their potential antibacterial activity and especially all the compounds except 5g were found more active than the standard drug ciprofloxacin against B. subtilis. To further gain insights into the possible mechanism of these compounds in biofilm inhibition through the agglutinin like protein (Als), molecular docking and molecular dynamics simulation studies were carried out. Molecular modeling studies suggested the clear role in inhibition of this protein and the resulting biofilm inhibitory activity.}, } @article {pmid30594718, year = {2019}, author = {Zhang, X and Chen, Z and Ma, Y and Zhang, N and Pang, Q and Xie, X and Li, Y and Jia, J}, title = {Response of Anammox biofilm to antibiotics in trace concentration: Microbial activity, diversity and antibiotic resistance genes.}, journal = {Journal of hazardous materials}, volume = {367}, number = {}, pages = {182-187}, doi = {10.1016/j.jhazmat.2018.12.082}, pmid = {30594718}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; *Bioreactors ; Drug Resistance, Microbial/*genetics ; Erythromycin/*pharmacology ; Genes, Bacterial ; Norfloxacin/*pharmacology ; Oxidoreductases/metabolism ; RNA, Ribosomal, 16S ; Waste Disposal, Fluid ; Wastewater ; Water Pollutants, Chemical/*pharmacology ; }, abstract = {Long-term impacts of two antibiotics-norfloxacin (NOR) and erythromycin (ERY) in trace concentration (1ug L[-1]) on Anammox biofilm were investigated. The specific Anammox activity (SAA) and dehydrogenase activity (DHA) of Anammox biofilm were detected by batch experiments, the microbial diversity was analyzed using high-throughput sequencing technology and the antibiotic resistance genes (ARGs) were measured by qPCR. Results showed that long-term NOR feeding decreased 30% SAA and 39.6% DHA, and also decreased the abundance of the OTUs related to autotrophic nitrogen removal, while ERY had slight impact on Anammox. Only two ARGs targeted to ERY (ermB, mphA) were detected in the two Anammox systems while those targeted to NOR (qnrA, qnrB, qnrD, and qnrS) were not detected. The relative expression of ermB to 16S rRNA increased from 2.08±0.32×10[-4] to 3.53±1.18×10[-4], and that of mphA increased to 5.00±0.48×10[-4] from 4.48±1.32×10[-5]. The induced ARGs in the Anammox system help it resist the ERY shock.}, } @article {pmid30594172, year = {2018}, author = {Tao, D and Li, F and Feng, X and Wong, MCM and Lu, H}, title = {Plaque biofilm microbial diversity in infants aged 12 months and their mothers with or without dental caries: a pilot study.}, journal = {BMC oral health}, volume = {18}, number = {1}, pages = {228}, pmid = {30594172}, issn = {1472-6831}, mesh = {Adult ; *Biofilms ; Case-Control Studies ; Dental Caries/etiology/*microbiology ; Dental Plaque/*microbiology ; Female ; Humans ; Infant ; Infectious Disease Transmission, Vertical ; *Microbiota/genetics ; Pilot Projects ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, RNA ; Surveys and Questionnaires ; }, abstract = {BACKGROUND: A number of studies on oral microbial diversity of early childhood caries (ECC) have tended to focus on mid- or late-stage of ECC, with a lack of research into early stage of tooth eruption and maternal influence. The aims of this study are to compare the supragingival plaque biofilm microbiota diversity between mothers with or without dental caries and their 12-month-old infants, and to explore the relationship of microbial diversity between infants and their mothers, using sequencing analysis.

METHODS: Supragingival plaque biofilm samples were collected from 20 pairs of mothers and their infants aged 12 months (10 mothers with dental caries and their 10 infants vs. 10 caries-free mothers and their 10 infants). The basic information of the mothers and infants had been collected through self-completed questionnaire. Pooled plaque biofilm DNA was extracted and DNA amplicons of the V4-V5 hypervariable region of the bacterial 16S rRNA gene were generated. Ilumina Miseq PE300 was used for 16S rRNA sequencing.

RESULTS: The results showed that high bacterial diversity was noted in the plaque biofilm of infants and their mothers with or without dental caries (dental caries mothers vs. caries-free mothers: 774 operational taxonomical units (OTUs) vs. 761 OTUs at a 3% divergence; infants whose mothers have dental caries vs. infants whose mothers are caries-free: 815 OTUs vs. 684 OTUs at 3% divergence). The Shannon microbial diversity index showed no statistically significant differences both on infants and their mothers between two groups (p > 0.05). Mother's microbial diversity was higher than infants' based on Shannon index (p < 0.05). Significant positive correlations were found between mothers' and their infants' Shannon index (r = 0.656, p = 0.002).

CONCLUSION: Oral microbial diversity is significantly different between mothers and infants regardless of dental caries status, but no significant difference was found between mothers with and without dental caries or between their infants. Mother's oral microbial diversity has an overall impact on the infants aged 12 months.}, } @article {pmid30594087, year = {2019}, author = {Gora, SL and Rauch, KD and Ontiveros, CC and Stoddart, AK and Gagnon, GA}, title = {Inactivation of biofilm-bound Pseudomonas aeruginosa bacteria using UVC light emitting diodes (UVC LEDs).}, journal = {Water research}, volume = {151}, number = {}, pages = {193-202}, doi = {10.1016/j.watres.2018.12.021}, pmid = {30594087}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; *Disinfection ; *Pseudomonas aeruginosa ; Ultraviolet Rays ; }, abstract = {Ultraviolet light emitting diodes (UV LEDs) are a promising technology for the disinfection of water and wetted surfaces, but research into these applications remains limited. In the drinking water field, UV LEDs emitting at wavelengths ranging from 254 nm to 285 nm (UVC LEDs) have been shown to be effective for the inactivation of numerous pathogens and pathogen surrogate organisms at UV doses comparable to conventional germicidal UV lamps. Surface disinfection with UV light, from UVC LEDs or from conventional UV lamps, is not as well understood. As the technology underlying the design and construction of UV LEDs matures and their energy efficiency improves, it is likely that they will become ubiquitous in small scale water treatment applications and surface disinfection in various industries, including the medical and dental fields. A simple, easily replicated methodology was developed and optimized to grow, irradiate, and recover biofilms from coupons. It was hypothesized that higher UV doses would be required to inactivate biofilm-bound bacteria than planktonic (free-floating) bacteria because the biofilm would provide some degree of protection from the effects of UVC irradiation. Indeed, UV LED irradiation at 265 nm achieved 1.3 ± 0.2 log inactivation of biofilm-bound Pseudomonas aeruginosa at a UV dose of 8 mJ/cm[2]. This inactivation level is lower than those that have been reported by researchers using UVC LEDs to inactivate planktonic P. aeruginosa, a finding that can be explained by the higher resistance of biofilm-bound bacteria to UV inactivation. A dose-response curve was developed and fitted to three disinfection models: the Chick-Watson model, the multi-target model, and the Geeraerd model. This last, which posits a subpopulation of organisms that are resistant to treatment, was a good fit to the dose-response data. ATP results obtained using the biomass recovery ATP method (ATPBR), a method that includes a 4 h incubation period after treatment, was well correlated to the results of conventional plate counts.}, } @article {pmid30594003, year = {2019}, author = {Zhang, C and Brown, PJB and Miles, RJ and White, TA and Grant, DG and Stalla, D and Hu, Z}, title = {Inhibition of regrowth of planktonic and biofilm bacteria after peracetic acid disinfection.}, journal = {Water research}, volume = {149}, number = {}, pages = {640-649}, doi = {10.1016/j.watres.2018.10.062}, pmid = {30594003}, issn = {1879-2448}, mesh = {Bacteria ; Biofilms ; Chlorine ; *Disinfectants ; Disinfection ; *Peracetic Acid ; Plankton ; }, abstract = {Peracetic acid (PAA) is a promising alternative to chlorine for disinfection; however, bacterial regrowth after PAA disinfection is poorly understood. This study compared the regrowth of bacteria (Gram-negative Pseudomonas aeruginosa PAO1 and Gram-positive Bacillus sp.) after disinfection with PAA or free chlorine. In the absence of organic matter, PAA and free chlorine prevented the regrowth of planktonic cells of P. aeruginosa PAO1 at C·t (= disinfectant concentration × contact time) doses of (28.5 ± 9.8) mg PAA·min·L[-1] and (22.5 ± 10.6) mg Cl2·min·L[-1], respectively, suggesting that they had comparable efficiencies in preventing the regrowth of planktonic bacteria. For comparison, the minimum C·t doses of PAA and free chlorine to prevent the regrowth of P. aeruginosa PAO1 biofilm cells in the absence of organic matter were (14,000 ± 1,732) mg PAA·min·L[-1] and (6,500 ± 2,291) mg Cl2·min·L[-1], respectively. PAA was less effective than free chlorine in killing bacteria within biofilms in the absence of organic matter most likely because PAA reacts with biofilm matrix constituents slower than free chlorine. In the presence of organic matter, although the bactericidal efficiencies of both disinfectants significantly decreased, PAA was less affected due to its slower reaction with organic matter and/or slower self-decomposition. For instance, in a dilute Lysogeny broth-Miller, the minimum concentrations of PAA and free chlorine to prevent the regrowth of planktonic P. aeruginosa PAO1 were 20 mg PAA·L[-1] and 300 mg Cl2·L[-1], respectively. While both disinfectants are strong oxidants disrupting cell membrane, environmental scanning electron microscopy (ESEM) revealed that PAA made holes in the center of the cells, whereas free chlorine desiccated the cells. Overall, this study shows that PAA is a powerful disinfectant to prevent bacterial regrowth even in the presence of organic matter.}, } @article {pmid30593855, year = {2019}, author = {Sun, X and Wang, L and Lynch, CD and Sun, X and Li, X and Qi, M and Ma, C and Li, C and Dong, B and Zhou, Y and Xu, HHK}, title = {Nanoparticles having amphiphilic silane containing Chlorin e6 with strong anti-biofilm activity against periodontitis-related pathogens.}, journal = {Journal of dentistry}, volume = {81}, number = {}, pages = {70-84}, doi = {10.1016/j.jdent.2018.12.011}, pmid = {30593855}, issn = {1879-176X}, mesh = {*Biofilms ; Chlorophyllides ; Humans ; *Nanoparticles ; Periodontitis/*microbiology ; Photochemotherapy ; *Porphyrins ; *Silanes ; }, abstract = {OBJECTIVES: The objectives of this study were to: (1) develop the multifunctional nanoparticles containing Chlorin e6 (Ce6), Coumarin 6 (C6) and Fe3O4 nanoparticles (NPs); and (2) investigate the inhibitory effects of the nanoparticles via antibacterial photodynamic therapy (aPDT) against three species of periodontitis-related pathogens for the first time.

MATERIALS AND METHODS: Ce6 and C6 were co-loaded into the Fe3O4-silane core-shell structure to form multifunctional nanoparticles (denoted "Fe3O4-silane@Ce6/C6 MNPs"). The physical and chemical properties of nanoparticles were characterized. Biofilm properties of Streptococcus sanguinis, Porphyromonas gingivalis and Fusobacterium nucleatum were tested. Colony-forming units (CFU), live/dead assay, and metabolic activity of biofilms were determined to evaluate the aPDT function mediated by the Fe3O4-silane@Ce6/C6 MNPs. Fluorescence imaging and the targeted antibacterial effects were also investigated.

RESULTS: Fe3O4-silane@Ce6/C6 MNPs showed superparamagnetic properties, chemical stability and water-solubility, with no cytotoxicity. Fe3O4 NPs did not compromise the emission peaks of C6 and Ce6. The Fe3O4-silane@Ce6/C6-mediated aPDT had much greater reduction in biofilms than the control groups (p < 0.05). Biofilm CFU was reduced by about 4-5 orders of magnitude via Fe3O4-silane@Ce6/C6-mediated aPDT. The co-loading of Ce6 and C6 enabled the real-time aPDT monitoring by ratio emissions with the same wavelength. Fe3O4 with magnetic field enabled the targeting of infection sites by killing bacteria via magnetic field.

CONCLUSION: The multifunctional nanoparticles exerted strong anti-biofilm activity against periodontitis-related pathogens, with excellent biocompatibility, real-time monitoring, and magnetically-targeting capacities. The multifunctional nanoparticles have great potential in antibacterial applications to inhibit the occurrence and progression of periodontitis.}, } @article {pmid30592126, year = {2019}, author = {Zhu, J and Yan, Y and Wang, Y and Qu, D}, title = {Competitive interaction on dual-species biofilm formation by spoilage bacteria, Shewanella baltica and Pseudomonas fluorescens.}, journal = {Journal of applied microbiology}, volume = {126}, number = {4}, pages = {1175-1186}, doi = {10.1111/jam.14187}, pmid = {30592126}, issn = {1365-2672}, support = {2017SICR105//Food Safety and Nutritional Central Program of Zhejiang Province/ ; FDMV-2017001//Open Collaboration Program of MOE/MOH Key Laboratory of Medical Molecular Virology/ ; }, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Cold Temperature ; Fishes/microbiology ; *Microbial Interactions ; Polysaccharides, Bacterial/biosynthesis ; Pseudomonas fluorescens/*physiology ; Seafood/microbiology ; Shewanella/*physiology ; }, abstract = {AIMS: This study aims to characterize the biofilm produced by mono- and dual-species of Shewanella baltica and Pseudomonas fluorescens as fish spoilers at the different incubation temperature, and to elucidate the interactive behaviour of dual-species biofilm development.

METHODS AND RESULTS: The mono- and dual-species biofilm formation and adhesion characteristics of S. baltica and P. fluorescens were evaluated by using crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy. Results showed that P. fluorescens had significantly higher biofilm biomass and polysaccharides production than S. baltica, and two isolates reached the maximum biofilm biomass during the early stationary phase. Lower biomass and polysaccharides in dual-species biofilms were observed compared to mono-species of P. fluorescens. Meanwhile, S. baltica and P. fluorescens formed fragile and viscous pellicles with different spatial architectures respectively. In dual-species pellicle few large microcolonies were dominated by P. fluorescens. Compared to mono-species of PF07, adherent cell population and biofilm thickness at the developing phase significantly decreased, and biofilm-forming cycle prolonged in the dual-species biofilms. Biofilm formation and adhesion of mono- and dual-species at 4 or 15°C were significantly higher than at 30°C during the same phase. The culture supernatant extracts of the two spoilage strains greatly inhibited biofilm development to each other.

CONCLUSIONS: Shewanella baltica and P. fluorescens had different biofilm and pellicle characteristics, and the inhibitory development on dual-species biofilm was associated with the competitive interaction by the two psychrotrophic spoilage bacteria.

This work contributes to a better understanding of interactive behaviour of multispecies biofilm communities by psychrotrophic spoilage bacteria at low temperature, which could contribute to further control contamination of spoilage organism during the preservation and processing of aquatic products.}, } @article {pmid30591789, year = {2018}, author = {Nuño, G and Alberto, MR and Arena, ME and Zampini, IC and Isla, MI}, title = {Effect of Zuccagnia punctata Cav. (Fabaceae) extract on pro-inflammatory enzymes and on planktonic cells and biofilm from Staphylococcus aureus. Toxicity studies.}, journal = {Saudi journal of biological sciences}, volume = {25}, number = {8}, pages = {1713-1719}, pmid = {30591789}, issn = {1319-562X}, abstract = {Zuccagnia punctata Cav. (Fabaceae), a native plant from Argentina has been used traditionally as medicinal species. The aim of the study was to validate the antibiotic and anti-inflammatory potential of Z. punctata organic extract (ZpE) and the major compounds; 2',4'-dihydroxy-3'-methoxychalcone (DHMC), 2',4'-dihydroxychalcone (DHC), 7-hydroxyflavanone (7-HF) and 3,7-dihydroxyflavone (DHF); using an in vitro model. The antibiotic activity was determined using a broth microdilution method and the minimum inhibitory concentration (MIC) was determined. The extract and the isolation compounds affect the normal growth of all assayed Staphylococcus aureus strains. The MIC values for ZpE and isolated compounds were between 125 and 500 μg/mL and between 25 and 400 μg/mL, respectively, against all assayed strains. The inhibitory effect of extract and isolated compounds on biofilm formation and on pro-inflammatory enzymes (sPLA2, COX-2, LOX) was analyzed. The compound DHC was the most active on sPLA2 while DHF and DHMC showed the highest activity on LOX. Both the extract and pure compounds except DHMC were active against COX-2. It can be concluded that the phytocomplex and the pure compounds possessed antibiotic and anti-inflammatory activities under the conditions tested, and could be a good alternative therapy for infective and inflammatory processes.}, } @article {pmid30590127, year = {2019}, author = {Milho, C and Andrade, M and Vilas Boas, D and Alves, D and Sillankorva, S}, title = {Antimicrobial assessment of phage therapy using a porcine model of biofilm infection.}, journal = {International journal of pharmaceutics}, volume = {557}, number = {}, pages = {112-123}, doi = {10.1016/j.ijpharm.2018.12.004}, pmid = {30590127}, issn = {1873-3476}, mesh = {Animals ; Bacteria ; Bacterial Infections/*therapy ; Bacterial Physiological Phenomena ; *Biofilms ; *Phage Therapy ; Skin/microbiology ; Skin Diseases/*therapy ; Swine ; }, abstract = {Antibiotic resistant bacterial communities persist in many types of wounds, chronic wounds in particular, in the form of biofilms. Biofilm formation is a major cause of severe infections and the main reason for a negative treatment outcome and slow healing progression. Chronic wounds are a silent epidemic essentially affecting people with co-morbid conditions such as diabetes and obesity and elderly persons particularly those with movement limitations. The development of complementary and alternative effective strategies to antibiotics for the treatment of chronic wounds is highly desired. Phage therapy constitutes a very promising approach in the control of topical microbial populations. In this work newly isolated phages were tested for their efficacy to control bacterial species that predominate in chronic wounds. Phage effectiveness was studied on 24-h old biofilms formed in polystyrene microplates and in porcine skin explants using two treatment approaches: individual phage and a cocktail of phages against four main pathogens commonly isolated from chronic wounds. The two models produced variations in the surface colonization ability, assessed by viable bacterial counts and microscopy visualization after using peptide nucleic acid (PNA) or locked nucleic acid probes (LNA) and 2'-O-methyl (2'-OMe) in fluorescence in situ hybridization (FISH), and in the phage-host interactions. Phages alone and combined caused greater reductions in the number of viable cells when biofilms had been formed on porcine skins and with greater variations detected at 4 h and 24 h of sampling. These results suggest that porcine skin models should be preferentially used to assess the use of phages and phage cocktails intended for topical use in order to understand the fate, throughout treatment time, of the population when dealing with biofilm-related infections.}, } @article {pmid30589915, year = {2018}, author = {Ostapska, H and Howell, PL and Sheppard, DC}, title = {Deacetylated microbial biofilm exopolysaccharides: It pays to be positive.}, journal = {PLoS pathogens}, volume = {14}, number = {12}, pages = {e1007411}, pmid = {30589915}, issn = {1553-7374}, support = {#81361//CIHR/Canada ; #123306//Canadian Institutes of Health Research/International ; #43998//Canadian Institutes of Health Research/International ; #13337//Canadian Institutes of Health Research/International ; #FDN154327//Canadian Institutes of Health Research/International ; }, mesh = {*Biofilms ; *Polysaccharides ; *Virulence ; }, } @article {pmid30588133, year = {2018}, author = {Pathak, R and Bierman, SF and d'Arnaud, P}, title = {Inhibition of bacterial attachment and biofilm formation by a novel intravenous catheter material using an in vitro percutaneous catheter insertion model.}, journal = {Medical devices (Auckland, N.Z.)}, volume = {11}, number = {}, pages = {427-432}, pmid = {30588133}, issn = {1179-1470}, abstract = {INTRODUCTION: Despite sterile barrier precautions and vigorous skin antisepsis, percutaneous insertion of intravenous catheters has been shown to result in attachment to the catheter surface of bacteria residing in the deep structures of the skin. Such attachment poses the risk of biofilm formation and eventual catheter-related bloodstream infection (CRBSI). This study was undertaken to assess whether the non-coated surface treatment of a unique catheter material (ChronoFlex C[®] with BioGUARD™) could inhibit bacterial attachment and biofilm formation.

METHODS: A novel in vitro model and fluorescence microscopy were used to compare two intravascular catheter materials with respect to bacterial attachment and biofilm formation. The control material was a commonly used polyurethane. The study material was a unique copolymer, treated so as to remove surface additives, alter hydrophobicity and create surface micro-patterning. Outcomes were assessed using both a membrane potential indicator and a cell death reporter with appropriate fluorescent channels. Thus, bacterial cells attached to the catheter surface (living and dead) were imaged without mechanical disruption.

RESULTS: Both bacterial attachment and biofilm formation are significantly inhibited by the study catheter material. In fact, over 5 times more bacteria were able to attach and grow on the control polyurethane material than on the study material (P=0.0020). Moreover, those few bacteria that were able to attach to the study material had a 1.5 times greater likelihood of dying.

CONCLUSION: Using a novel in vitro percutaneous catheter insertion model, ChronoFlex C with BioGUARD is proven to significantly inhibit bacterial attachment and biofilm formation as compared with a commonly used polyurethane catheter material.}, } @article {pmid30587467, year = {2018}, author = {Khalid, R and Jaffar, Q and Tayyeb, A and Qaisar, U}, title = {Peganum harmalapeptides (PhAMP) impede bacterial growth and biofilm formation in burn and surgical wound pathogens.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {31}, number = {6 (Supplementary}, pages = {2597-2605}, pmid = {30587467}, issn = {1011-601X}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; Burns/drug therapy/*microbiology ; Humans ; Microbial Sensitivity Tests ; *Peganum ; Peptide Fragments/isolation & purification/pharmacology/therapeutic use ; Plant Extracts/isolation & purification/*pharmacology/therapeutic use ; Plant Proteins/isolation & purification/pharmacology/therapeutic use ; Pseudomonas aeruginosa/drug effects/isolation & purification/physiology ; Staphylococcus aureus/drug effects/isolation & purification/physiology ; Surgical Wound/drug therapy/*microbiology ; }, abstract = {Many clinical-pathogens have developed resistance against known antibiotics and there is an urgent need for the discovery of novel antibiotics. In this study, low molecular weight peptides were isolated from seeds/leaves of 20 medicinal plants and tested for their antibacterial activity against laboratory strains of S. aureusand P. aeruginosa. Peptides isolated from Peganum harmala (PhAMP) exhibited maximum activity against laboratory strains. As clinical-isolates are more virulent and resistant to antibiotics, we tested the potential of PhAMP on these bacterial strains isolated from infected wounds. Pathogens isolated from burn-wounds (S. aureus, P. aeruginosa and K. pneumoniae) and surgical-wounds (P. aeruginosa and K. pneumoniae) exhibited zones of inhibition against PhAMP when tested by disc diffusion method. Biofilm formation of wound pathogens in the presence/absence of PhAMP was analyzed to check its effect. Surgical-wound pathogens and K. pneumoniae from burn-wound showed significant reduction in biofilm formation and planktonic bacteria. While biofilms of S. aureus and P. aeruginosa from burn-wound showed resistance against PhAMP. An effective antibiotic treatment should not only inhibit but should also disrupt already developed biofilms. PhAMP was very effective in the disruption of developed biofilm of all pathogens after 36 hours. This data unravels the potential of PhAMP as a novel, natural antibiotic against clinical-pathogens.}, } @article {pmid30586583, year = {2019}, author = {Felipe, V and Breser, ML and Bohl, LP and Rodrigues da Silva, E and Morgante, CA and Correa, SG and Porporatto, C}, title = {Chitosan disrupts biofilm formation and promotes biofilm eradication in Staphylococcus species isolated from bovine mastitis.}, journal = {International journal of biological macromolecules}, volume = {126}, number = {}, pages = {60-67}, doi = {10.1016/j.ijbiomac.2018.12.159}, pmid = {30586583}, issn = {1879-0003}, mesh = {Animals ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Cattle ; Chitosan/*pharmacology ; Female ; Mastitis, Bovine/*microbiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Molecular Weight ; Staphylococcus/drug effects/*growth & development/*isolation & purification/ultrastructure ; }, abstract = {Staphylococci are the main pathogens associated with hard-to-control intramammary infections in dairy cattle, and bacterial biofilms are suspected to be responsible for the antimicrobial resistance and persistence of this disease. Biofilms have the ability to resist to higher levels of antibiotics and reduce their efficacy. It is thus necessary to develop strategies targeted to bacterial biofilm infections. Chitosan is a polysaccharide with a proven broad spectrum of antimicrobial activity against fungi and bacteria. The aim of this study was assess the effect of low molecular weight (LMW) chitosan against biofilm hyperproducer Staphylococcus spp. (S. aureus and S. xylosus) strains usually involved in chronic bovine mastitis, and to test their efficacy in biofilm formation and eradication. The results obtained showed that LMW chitosan is able to inhibit S. aureus and S. xylosus planktonic growth in a dose-dependent manner and reduce bacterial viability. LMW chitosan inhibits biofilm formation, reduces biofilm viability and disrupts established biofilm. These results indicate the inhibitory effects of chitosan on biofilm formation, and these effects are observed at lower concentrations for S. xylosus. Our studies show the potential of this biopolymer to be used as an effective antibiofilm agent able to act upon staphylococcal infections.}, } @article {pmid30586327, year = {2019}, author = {Dhakal, J and Sharma, CS and Nannapaneni, R and McDANIEL, CD and Kim, T and Kiess, A}, title = {Effect of Chlorine-Induced Sublethal Oxidative Stress on the Biofilm-Forming Ability of Salmonella at Different Temperatures, Nutrient Conditions, and Substrates.}, journal = {Journal of food protection}, volume = {82}, number = {1}, pages = {78-92}, doi = {10.4315/0362-028X.JFP-18-119}, pmid = {30586327}, issn = {1944-9097}, mesh = {Biofilms/*growth & development ; *Chlorine/pharmacology ; Colony Count, Microbial ; *Nutrients ; *Oxidative Stress ; Salmonella/*physiology ; Stainless Steel ; Temperature ; }, abstract = {The present study was conducted to evaluate the effect of chlorine-induced oxidative stress on biofilm formation by various Salmonella strains on polystyrene and stainless steel (SS) surfaces at three temperatures (30, 25 [room temperature], and 4°C) in tryptic soy broth (TSB) and 1/10 TSB. Fifteen Salmonella strains (six serotypes) were exposed to a sublethal chlorine concentration (150 ppm of total chlorine) in TSB for 2 h at the predetermined temperatures. The biofilm-forming ability of the Salmonella strains was determined in 96-well polystyrene microtiter plates by using a crystal violet staining method and on SS coupons in 24-well tissue culture plates. All tested strains of Salmonella produced biofilms on both surfaces tested at room temperature and at 30°C. Of the 15 strains tested, none (chlorine stressed and nonstressed) formed biofilm at 4°C. At 30°C, Salmonella Heidelberg (ID 72), Salmonella Newport (ID 107), and Salmonella Typhimurium (ATCC 14028) formed more biofilm than did their respective nonstressed controls on polystyrene (P ≤ 0.05). At room temperature, only stressed Salmonella Reading (ID 115) in 1/10 TSB had significantly more biofilm formation than did the nonstressed control cells (P ≤ 0.05). Salmonella strains formed more biofilm in nutrient-deficient medium (1/10 TSB) than in full-strength TSB. At 25°C, chlorine-stressed Salmonella Heidelberg (ATCC 8326) and Salmonella Enteritidis (ATCC 4931) formed stronger biofilms on SS coupons (P ≤ 0.05) than did the nonstressed cells. These findings suggest that certain strains of Salmonella can produce significantly stronger biofilms on plastic and SS upon exposure to sublethal chlorine.}, } @article {pmid30584258, year = {2018}, author = {Jadoun, J and Mreny, R and Saad, O and Azaizeh, H}, title = {Fate of bacterial indicators and Salmonella in biofilm developed on ultrafiltration membranes treating secondary effluents of domestic wastewater.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {18066}, pmid = {30584258}, issn = {2045-2322}, support = {2334/WT 1104//Ministry of Science, Technology and Space/International ; 2334/WT 1104//Bundesministerium für Bildung und Forschung (Federal Ministry of Education and Research)/International ; }, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Membranes, Artificial ; Salmonella/drug effects/pathogenicity/*physiology ; Sodium Hypochlorite/pharmacology ; Ultrafiltration/*methods ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {The fate of representative indicator and pathogenic bacteria on ultrafiltration (UF)-membrane surfaces treating secondary wastewater effluent, as well as their reaction to common biofouling-removal techniques was investigated. Field-condition experiments showed that the number of heterotrophic bacteria, fecal coliforms, E. coli and Salmonella on membrane surface increased rapidly and continuously until the end of the experiment, reaching 9, 6.5, 6, and 2.4 logs, respectively. Similar results were obtained under controlled laboratory conditions. However, the increase in the bacterial numbers was dependent on the supply of fresh wastewater. Quantitative real-time PCR verified the behavior of attached E. coli cells, although the numbers were 1-2 logs higher compared to the standard culture-based method. The number of attached bacteria was positively correlated to increases in DNA and protein content and negatively correlated to the membrane flux. In-situ membrane cleaning using sodium hypochlorite significantly reduced the number of attached bacteria. However, the effect was temporary and affected bacterial cell cultivability rather than viability. Taken together, these findings suggest that, under the studied conditions, indicator and pathogenic bacteria can initiate rapid biofilm development, persist on UF membrane surfaces, and survive membrane cleaning with sodium hypochlorite.}, } @article {pmid30583280, year = {2019}, author = {Jing, X and Liu, X and Deng, C and Chen, S and Zhou, S}, title = {Chemical signals stimulate Geobacter soli biofilm formation and electroactivity.}, journal = {Biosensors & bioelectronics}, volume = {127}, number = {}, pages = {1-9}, doi = {10.1016/j.bios.2018.11.051}, pmid = {30583280}, issn = {1873-4235}, mesh = {Acyl-Butyrolactones/chemistry ; Biofilms/*growth & development ; *Biosensing Techniques ; Electrochemical Techniques ; Extracellular Polymeric Substance Matrix ; Geobacter/chemistry/*isolation & purification ; *Quorum Sensing ; }, abstract = {Biofilm formation and maturation have been demonstrated to be regulated by distinct forms of cell-cell communication factors such as chemical and physical signals. However, whether the Geobacter sp. biofilms, which are typical electroactive biofilms, are affected by chemical signals is poorly understood. This research investigated the effects and corresponding mechanisms of endogenous and exogenous chemical signals (i.e., N-acylhomoserine lactones, AHLs) on the Geobacter soli biofilm. The results showed that Geobacter soli GSS01 secreted detectable endogenous AHLs to facilitate the formation and electrochemical activity of the biofilm, and that exogenous AHLs could further promoted these activities. Analyses of surface proteins revealed that the mechanisms promoted by endogenous and exogenous AHLs were somewhat different. Endogenous AHLs improved the relative abundance of external membrane proteins, while exogenous AHLs further facilitated the formation of amide II and a stronger H-bond between the carbonyl group and the amide. Furthermore, the proteomics analysis indicated that endogenous AHLs enhanced extracellular polymeric substance production by up-regulating the expression of key enzymes participating in EPS production, and simultaneously affected the physiological performance of individual cells. These results demonstrate, for the first time, the importance of chemical signals in Geobacter sp. and provide a comprehensive understanding of the chemical signals involved in biofilm formation and electrochemical activity of Geobacter sp..}, } @article {pmid30582054, year = {2018}, author = {Dua, P and Karmakar, A and Ghosh, C}, title = {Virulence gene profiles, biofilm formation, and antimicrobial resistance of Vibrio cholerae non-O1/non-O139 bacteria isolated from West Bengal, India.}, journal = {Heliyon}, volume = {4}, number = {12}, pages = {e01040}, pmid = {30582054}, issn = {2405-8440}, abstract = {Vibrio cholerae is the causative agent of acute dehydrating diarrhoeal disease cholera. Among 71 V. cholerae non-O1/non-O139 isolates, all yielded negative results for ctxA, ctxB and tcpA genes in PCR assay. Few strains were positive for stn (28.38%), and ompU (31.08%) genes. While all isolates were negative for ace gene, only two were positive for zot gene. All strains expressed toxR and toxT genes. It was also found that all isolates were slime-producer and these were capable of forming moderate to high biofilm. Biofilm formation was controlled positively by the transcriptional regulators VpsR and VpsT and was regulated negatively by HapR, as well as CRP regulatory complex. These isolates were resistant to ampicillin, furazolidone, doxycycline, vancomycin, erythromycin, while these were susceptible to ciprofloxacin, gentamycin, kanamycin, polymixin B, norfloxacin, chloramphenicol, sulphamethoxazole-trimethoprim, tetracycline, nalidixic acid, and streptomycin. Indeed, 69.01% isolates were resistant to multiple antibiotics (MAR: resistance to 3 or more antibiotics). Treatment protocols for cholera patients should be based on local antibiogram data.}, } @article {pmid30581995, year = {2018}, author = {Diaconu, O and Siriopol, I and Poloșanu, LI and Grigoraș, I}, title = {Endotracheal Tube Biofilm and its Impact on the Pathogenesis of Ventilator-Associated Pneumonia.}, journal = {Journal of critical care medicine (Universitatea de Medicina si Farmacie din Targu-Mures)}, volume = {4}, number = {2}, pages = {50-55}, pmid = {30581995}, issn = {2393-1809}, abstract = {Ventilator-associated pneumonia (VAP) is a common and serious nosocomial infection in mechanically ventilated patients and results in high mortality, prolonged intensive care unit- (ICU) and hospital-length of stay and increased costs. In order to reduce its incidence, it is imperative to better understand the involved mechanisms and to identify the source of infection. The role of the endotracheal tube (ET) in VAP pathogenesis became more prominent over the last decades, along with extensive research dedicated to medical device-related infections and biofilms. ET biofilm formation is an early and constant process in intubated patients. New data regarding its temporal dynamics, composition, germ identification and consequences enhance knowledge about VAP occurrence, microbiology, treatment response and recurrence. This paper presents a structured analysis of the medical literature to date, in order to outline the role of ET biofilm in VAP pathogenesis and to review recommended methods to identify ET biofilm microorganisms and to prevent or decrease VAP incidence.}, } @article {pmid30581573, year = {2019}, author = {Ghasemian, A and Mobarez, AM and Peerayeh, SN and Bezmin Abadi, AT}, title = {The association of surface adhesin genes and the biofilm formation among Klebsiella oxytoca clinical isolates.}, journal = {New microbes and new infections}, volume = {27}, number = {}, pages = {36-39}, pmid = {30581573}, issn = {2052-2975}, abstract = {Bacterial adhesins mediate the attachment and biofilm production leading to the persistence of colonized strains. The aim of this study was evaluation of the association of surface adhesin genes with the biofilm formation among Klebsiella oxytoca isolates. Among 50 isolates of K. oxytoca from patients with antibiotic-associated diarrhoea, the susceptibility test, MIC (according to CLSI 2016) and phenotypic biofilm formation (with microtitre tissue-plate assay) were performed. The presence of adhesins was investigated using PCR. Thirty-three (66%) isolates produced moderate-level biofilms, but none of them exhibited strong biofilm formation. The presence of adhesins was as follows: fimA, 60% (n = 30), mrkA, 42% (n = 21), matB, 96% (n = 48) and pilQ, 92% (n = 46). The biofilm formation was related to the presence of fimA (odds ratio (OR) 0.8571, 95% CI 1.733-6.267, p <0.0001), mrkA (OR 0.2462, 95% CI 2.723-4.622, p 0.001), matB (OR 0.4521, 95% CI 1.353-5.332, p 0.008) and pilQ (OR 0.1481, 95% CI 1.691-6.117, p <0.0001). The npsB toxin-encoding gene was detected among 46 (92%) isolates. Resistance to non-β-lactam antibiotics was significantly associated with the presence of adhesin-encoding genes. The presence of adhesins and the capsular encoding gene was significantly associated with biofilm formation among K. oxytoca isolates. The presence of surface adhesin-encoding genes was significantly associated with the biofilm formation and also with resistance to non-β-lactam antibiotics among K. oxytoca clinical isolates. In addition, biofilm production was not significantly associated with β-lactam resistance among the isolates.}, } @article {pmid30580408, year = {2019}, author = {Canette, A and Deschamps, J and Briandet, R}, title = {High Content Screening Confocal Laser Microscopy (HCS-CLM) to Characterize Biofilm 4D Structural Dynamic of Foodborne Pathogens.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1918}, number = {}, pages = {171-182}, doi = {10.1007/978-1-4939-9000-9_14}, pmid = {30580408}, issn = {1940-6029}, mesh = {*Biofilms ; Data Analysis ; Foodborne Diseases/diagnosis/*microbiology ; *High-Throughput Screening Assays ; Image Processing, Computer-Assisted/methods ; *Microscopy, Confocal/methods ; }, abstract = {The functional properties of biofilms are intimately related to their spatial architecture. Structural data are therefore of prime importance to dissect the complex social and survival strategies of biofilms and ultimately to improve their control. Confocal laser microscopy (CLM) is the most widespread microscopic tool to decipher biofilm structure, enabling noninvasive 3D investigation of their dynamics down to single cell scale. The emergence of fully automated high content screening (HCS) systems, associated with large-scale image analysis, radically amplifies the flow of available biofilm structural data. In this contribution, we present an HCS-CLM protocol used to analyze biofilm 4D structural dynamics at high throughput. Meta-analysis of the quantitative variates extracted from HCS-CLM will contribute to a better biological understanding of biofilm traits.}, } @article {pmid30580407, year = {2019}, author = {Dubois-Brissonnet, F}, title = {Characterization of Bacterial Membrane Fatty Acid Profiles for Biofilm Cells.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1918}, number = {}, pages = {165-170}, doi = {10.1007/978-1-4939-9000-9_13}, pmid = {30580407}, issn = {1940-6029}, mesh = {Bacteria/chemistry/*metabolism ; *Biofilms ; Cell Membrane/chemistry/*metabolism ; Chromatography, Gas ; Fatty Acids/chemistry/isolation & purification/*metabolism ; Membrane Lipids ; Metabolome ; Metabolomics/methods ; Plankton ; }, abstract = {When exposed to environmental stresses, bacteria can modulate its fatty acid composition of membrane phospholipids in order to optimize membrane fluidity. Characterization of bacterial membrane fatty acid profiles is thus an interesting indicator of cellular physiological state. The methodology described here aims to improve the recovering of biofilm cells for the characterization of their fatty acid profiles. The saponification reagent is directly applied on the whole biofilm before the removal of cells from the inert surface. In this way, maximum of the cells and their fatty acids can be recovered from the deepest layers of the biofilm.}, } @article {pmid30579592, year = {2019}, author = {He, L and Wang, H and Zhang, R and Li, H}, title = {The regulation of Porphyromonas gingivalis biofilm formation by ClpP.}, journal = {Biochemical and biophysical research communications}, volume = {509}, number = {2}, pages = {335-340}, doi = {10.1016/j.bbrc.2018.12.071}, pmid = {30579592}, issn = {1090-2104}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/*genetics/metabolism ; Endopeptidase Clp/deficiency/*genetics ; Fimbriae Proteins/*genetics/metabolism ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Gentian Violet ; Homologous Recombination ; Microscopy, Electron, Scanning ; Porphyromonas gingivalis/*genetics/growth & development/metabolism/ultrastructure ; }, abstract = {Porphyromonas gingivalis is one of the most commonly detected pathogens in periodontal disease and root canal infections. Its viability and pathogenicity are greatly increased in plaque biofilms. Some caseinolytic proteases (Clp) reportedly regulate biofilm formation by various pathogenic bacteria, including P. gingivalis. However, the specific influence of ClpP and its mechanism of regulating biofilm formation by P. gingivalis remains unclear. Hence, in this study, a clpP deletion strain and complemented strain were constructed by homologous recombination, and an in vitro biofilm model was established. Biofilm architecture was observed by scanning electron microscopy. Bacterial cells within the biofilms were examined using confocal scanning laser microscopy. Crystal violet staining was used to determine the amount of formed biofilm. mRNA levels of related regulatory genes were assessed using real-time PCR. The clpP deletion and complemented strains of P. gingivalis were successfully constructed. The biofilm formation ability of the deletion strain was significantly reduced compared with that of the wild-type strain, while that of the complemented strain did not differ from that of the wild-type strain. The expression of fimA, mfa1, and luxS in the deletion strain was lower than in the wild-type and complemented strains at each timepoint. It can be concluded that ClpP increases the biofilm formation of P. gingivalis by regulating the expression levels of fimA, mfa1, and luxS.}, } @article {pmid30578837, year = {2019}, author = {Bag, PK and Roy, N and Acharyya, S and Saha, DR and Koley, H and Sarkar, P and Bhowmik, P}, title = {In vivo fluid accumulation-inhibitory, anticolonization and anti-inflammatory and in vitro biofilm-inhibitory activities of methyl gallate isolated from Terminalia chebula against fluoroquinolones resistant Vibrio cholerae.}, journal = {Microbial pathogenesis}, volume = {128}, number = {}, pages = {41-46}, doi = {10.1016/j.micpath.2018.12.037}, pmid = {30578837}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Anti-Inflammatory Agents/*pharmacology ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Cholera/microbiology ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial/drug effects ; Fluoroquinolones/*pharmacology ; Gallic Acid/administration & dosage/*analogs & derivatives/isolation & purification/pharmacology ; Intestine, Small/pathology/virology ; Mice ; Mice, Inbred BALB C ; Plant Extracts/pharmacology ; Terminalia/*chemistry ; Vibrio cholerae/cytology/*drug effects/growth & development/pathogenicity ; }, abstract = {Acute Vibrio cholerae infection triggers significant inflammatory response and immense fluid secretion in the intestine. In the present study, methyl gallate (MG) isolated from Terminalia chebula was evaluated to determine the in vivo fluid accumulation-inhibitory, anticolonization and anti-inflammatory and in vitro biofilm-inhibitory activities against multi-drug resistant (MDR) V. cholerae. Bacterial membrane-damaging and biofilm-inhibitory activities were determined by membrane perturbation and transmission electron microscopy (TEM); and microdilution assays, respectively. Fluid accumulation-inhibitory and anticolonization activities of MG (23.80-95.23 mg/kg body weight) were determined in 4-5 days old BALB/c mice with an incubation time of 18 h. The effect of MG (1, 50 and 500 mg/kg body weight) on intestinal inflammatory reaction induced by V. cholerae was studied by performing histology in Swiss albino mice. MIC and MBC of MG against the test strains were 32-64 and 64-256 μg/ml, respectively. MG showed the fluid accumulation-inhibitory activity with inhibition values of 42.86-89.08% at doses between 23.80 and 95.23 mg/kg body weight and significant anticolonization activity (p < 0.0001) against V. choleare in the suckling mouse intestine. MG (500 mg/kg body weight) significantly inhibited the inflammatory reactions induced by V. cholerae compared to the vehicle control. MG exhibited 70% minimum biofilm inhibition concentration of 64 μg/ml and bacterial membrane damaging activity at 1 × MBC. The results obtained in the present study suggest that MG has potential as an effective agent for the treatment of severe secretory and inflammatory diarrheal disease caused by MDR V. cholerae.}, } @article {pmid30578260, year = {2019}, author = {Rainey, K and Michalek, SM and Wen, ZT and Wu, H}, title = {Glycosyltransferase-Mediated Biofilm Matrix Dynamics and Virulence of Streptococcus mutans.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {5}, pages = {}, pmid = {30578260}, issn = {1098-5336}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; R21 DE025348/DE/NIDCR NIH HHS/United States ; R01 DE017954/DE/NIDCR NIH HHS/United States ; F31 DE025805/DE/NIDCR NIH HHS/United States ; R01 DE022350/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; DNA, Bacterial/genetics/isolation & purification ; Dental Caries/microbiology ; Extracellular Matrix/metabolism ; Extracellular Polymeric Substance Matrix/genetics/*metabolism ; Female ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Glucans/metabolism ; Glycosyltransferases/genetics/*metabolism ; Hydrogen-Ion Concentration ; Male ; Molecular Weight ; Rats ; Streptococcus mutans/genetics/*metabolism ; Virulence ; }, abstract = {Streptococcus mutans is a key cariogenic bacterium responsible for the initiation of tooth decay. Biofilm formation is a crucial virulence property. We discovered a putative glycosyltransferase, SMU_833, in S. mutans capable of modulating dynamic interactions between two key biofilm matrix components, glucan and extracellular DNA (eDNA). The deletion of smu_833 decreases glucan and increases eDNA but maintains the overall biofilm biomass. The decrease in glucan is caused by a reduction in GtfB and GtfC, two key enzymes responsible for the synthesis of glucan. The increase in eDNA was accompanied by an elevated production of membrane vesicles, suggesting that SMU_833 modulates the release of eDNA via the membrane vesicles, thereby altering biofilm matrix constituents. Furthermore, glucan and eDNA were colocalized. The complete deletion of gtfBC from the smu_833 mutant significantly reduced the biofilm biomass despite the elevated eDNA, suggesting the requirement of minimal glucans as a binding substrate for eDNA within the biofilm. Despite no changes in overall biofilm biomass, the mutant biofilm was altered in biofilm architecture and was less acidic in vitro Concurrently, the mutant was less virulent in an in vivo rat model of dental caries, demonstrating that SMU_833 is a new virulence factor. Taken together, we conclude that SMU_833 is required for optimal biofilm development and virulence of S. mutans by modulating extracellular matrix components. Our study of SMU_833-modulated biofilm matrix dynamics uncovered a new target that can be used to develop potential therapeutics that prevent and treat dental caries.IMPORTANCE Tooth decay, a costly and painful disease affecting the vast majority of people worldwide, is caused by the bacterium Streptococcus mutans The bacteria utilize dietary sugars to build and strengthen biofilms, trapping acids onto the tooth's surface and causing demineralization and decay of teeth. As knowledge of our body's microbiomes increases, the need for developing therapeutics targeted to disease-causing bacteria has arisen. The significance of our research is in studying and identifying a novel therapeutic target, a dynamic biofilm matrix that is mediated by a new virulence factor and membrane vesicles. The study increases our understanding of S. mutans virulence and also offers a new opportunity to develop effective therapeutics targeting S. mutans In addition, the mechanisms of membrane vesicle-mediated biofilm matrix dynamics are also applicable to other biofilm-driven infectious diseases.}, } @article {pmid30577589, year = {2018}, author = {Ledwoch, K and Maillard, JY}, title = {Candida auris Dry Surface Biofilm (DSB) for Disinfectant Efficacy Testing.}, journal = {Materials (Basel, Switzerland)}, volume = {12}, number = {1}, pages = {}, pmid = {30577589}, issn = {1996-1944}, abstract = {Candida auris is an emerging pathogen that needs to be controlled effectively due to its association with a high mortality rate. The presence of biofilms on dry surfaces has been shown to be widespread in healthcare settings. We produced a C. auris dry surface biofilm (DSB) on stainless steel surfaces following sequential hydration and desiccation cycles for 12 days. The ASTM2967-15 was used to measure the reduction in viability of 12 commercially wipe-based disinfectants and sodium hypochlorite (1000 ppm) against C. auris DSB. We also evaluated C. auris transferability and biofilm regrowth post-treatment. A peracetic acid (3500 ppm) product and two chlorine-based products (1000 ppm available chlorine) were successful in reducing C. auris viability and delaying DSB regrowth. However, 50% of the products tested failed to decrease C. auris viability, 58% failed to prevent its transferability, and 75% did not delay biofilm regrowth. Using three different parameters to measure product efficacy provided a practical evaluation of product effectiveness against C. auris DSB. Although log10 reduction in viability is traditionally measured, transferability is an important factor to consider from an infection control and prevention point of view as it allows for determination of whether the surface is safe to touch by patients and hospital staff post-treatment.}, } @article {pmid30577115, year = {2019}, author = {Shi, LD and Du, JJ and Wang, LB and Han, YL and Cao, KF and Lai, CY and Zhao, HP}, title = {Formation of nanoscale Te[0] and its effect on TeO3[2-] reduction in CH4-based membrane biofilm reactor.}, journal = {The Science of the total environment}, volume = {655}, number = {}, pages = {1232-1239}, doi = {10.1016/j.scitotenv.2018.11.337}, pmid = {30577115}, issn = {1879-1026}, mesh = {*Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors ; Membranes, Artificial ; Methane/chemistry ; *Nanostructures ; Phylogeny ; RNA, Bacterial/analysis ; RNA, Ribosomal, 16S/analysis ; Tellurium/*metabolism ; Waste Disposal, Fluid/economics/*methods ; Wastewater/*analysis ; }, abstract = {Formation and recovery of elemental tellurium (Te[0]) from wastewaters are required by increasing demands and scarce resources. Membrane biofilm reactor (MBfR) using gaseous electron donor has been reported as a low-cost and benign technique to reduce and recover metal (loids). In this study, we demonstrate the feasibility of nanoscale Te[0] formation by tellurite (TeO3[2-]) reduction in a CH4-based MBfR. Biogenic Te[0] intensively attached on cell surface, within diameters ranging from 10 nm to 30 nm and the hexagonal nanostructure. Along with the Te[0] formation, the TeO3[2-] reduction was inhibited. After flushing, biofilm resumed the TeO3[2-] reduction ability, suggesting that the formed nanoscale Te[0] might inhibit the reduction by hindering substrate transfer of TeO3[2-] to microbes. The 16S rRNA gene amplicon sequencing revealed that Thermomonas and Hyphomicrobium were possibly responsible for TeO3[2-] reduction since they increased consecutively along with the experiment operation. The PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) analysis showed that the sulfite reductases were positively correlated with the TeO3[2-] flux, indicating they were potential enzymes involved in reduction process. This study confirms the capability of CH4-based MBfR in tellurium reduction and formation, and provides more techniques for resources recovery and recycles.}, } @article {pmid30572298, year = {2019}, author = {Zhao, Z and Qin, Z and Xia, L and Zhang, D and Mela, SM and Li, Y}, title = {The responding and ecological contribution of biofilm-leaves of submerged macrophytes on phenanthrene dissipation in sediments.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {246}, number = {}, pages = {357-365}, doi = {10.1016/j.envpol.2018.12.030}, pmid = {30572298}, issn = {1873-6424}, mesh = {Bacterial Physiological Phenomena ; *Biodegradation, Environmental ; *Biofilms ; Geologic Sediments/*chemistry/*microbiology ; Hydrocharitaceae/*metabolism ; Phenanthrenes/*metabolism ; Plant Leaves/*metabolism ; Rhizosphere ; }, abstract = {The bacterial communities and ecological contribution of biofilm-leaves of the Vallisneria natans (VN), Hydrilla verticillata (HV) and artificial plant (AP) settled in sediments with different polluted levels of phenanthrene were investigated by high-throughput sequencing in different growth periods. There was no significant difference among the detected Alpha diversity indices based on three classification, attached surface, spiking concentration and incubation time. While Beta diversity analysis assessed by PCoA on operational taxonomic units (OTU) indicated that bacterial community structures were significantly influenced in order of attached surface > incubation time > spiking concentration of phenanthrene in sediment. Moreover, the results of hierarchical dendrograms and heat maps at genus level were consistent with PCoA analysis. We speculated that the weak influence of phenanthrene spiking concentration in sediment might be related to lower concentration and smaller concentration gradient of phenanthrene in leaves. Meanwhile, difference analysis suggested that attached surface was inclined to influence the rare genera up to significant level than incubation time. In general, the results proved that phenanthrene concentrations, submerged macrophytes categories and incubation time did influence the bacterial community of biofilm-leaves. In turn, results also showed a non-negligible ecological contribution of biofilm-leaves in dissipating the phenanthrene in sediments (>13.2%-17.1%) in contrast with rhizosphere remediation (2.5%-3.2% for HV and 9.9%-10.6% for VN).}, } @article {pmid30572157, year = {2019}, author = {Singh, N and Rajwade, J and Paknikar, KM}, title = {Transcriptome analysis of silver nanoparticles treated Staphylococcus aureus reveals potential targets for biofilm inhibition.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {175}, number = {}, pages = {487-497}, doi = {10.1016/j.colsurfb.2018.12.032}, pmid = {30572157}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry ; Biofilms/*drug effects ; Biomarkers/analysis/*metabolism ; *Gene Expression Profiling ; High-Throughput Nucleotide Sequencing ; Metal Nanoparticles/*administration & dosage/chemistry ; Quorum Sensing ; Silver/*chemistry ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects/genetics ; Virulence/drug effects ; }, abstract = {The biofilms of Staphylococcus aureus on the implanted materials and chronic wounds are life-threatening and are a substantial financial burden on the healthcare system. Silver nanoparticles (SNP), known for their multi-level physiological effects in planktonic cells could be a promising agent in the treatment of biofilm-related infections also. To gain insight into the effects of SNP on various physiological processes in biofilms we studied the transcriptome of Staphylococcus aureus ATCC 29213. To distinguish between 'nanoparticles-specific' and 'ion-specific' effect of silver, we performed a comparative analysis of the functional genes in response to Ag[+]. As compared to untreated biofilms, 21% (i.e. 629 genes) and 28.5% (i. e. 830 genes) of the total functional coding genes were differentially regulated upon exposure to SNP and Ag[+]. Genes encoding capsular polysaccharides, intercellular adhesion, virulence were downregulated in SNP and Ag[+] treated biofilms. Genes involved in carbohydrate, protein metabolism including DNA and RNA synthesis, oxidative stress etc. were differentially expressed. Further, activation of efflux pumps and multidrug export proteins was observed, which clearly indicates the presence of metal stress resistance determinants in S. aureus. Silver blocked the integration of mobile genetic elements in S. aureus genome. Our study points out quorum sensing and virulence determinants as possible targets for inhibition of biofilms possibly with/without existing antibiotics. However, further studies on these aspects are warranted. Scanning electron microscopy (SEM) and confocal microscopy revealed changes in biofilm morphology, architecture and thickness in presence of silver nanoparticles and ionic silver, substantiating the transcriptome data.}, } @article {pmid30570729, year = {2019}, author = {Boas, DV and Almeida, C and Azevedo, N and Sillankorva, S and Azeredo, J}, title = {Techniques to Assess Phage-Biofilm Interaction.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1898}, number = {}, pages = {137-146}, doi = {10.1007/978-1-4939-8940-9_11}, pmid = {30570729}, issn = {1940-6029}, mesh = {Bacteriophages/*genetics/pathogenicity ; Biofilms/growth & development ; Host-Pathogen Interactions/*genetics ; Molecular Biology/*methods ; Pseudomonas aeruginosa/*genetics/growth & development/virology ; }, abstract = {Biofilms are ubiquitous in nature found on nearly every type of living and inert surface. They basically consist of microorganisms attached to surfaces and surrounded by a self-produced matrix of extracellular polymeric substances. Phages have proven to be successful in controlling biofilms. Here, we describe methods to characterize phage-biofilm interactions, specifically to assess biofilm biomass and to visualize the biofilm structure, discriminating infected cells using targeted molecular probes.}, } @article {pmid30567300, year = {2018}, author = {Alim, D and Sircaik, S and Panwar, SL}, title = {The Significance of Lipids to Biofilm Formation in Candida albicans: An Emerging Perspective.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {4}, number = {4}, pages = {}, pmid = {30567300}, issn = {2309-608X}, support = {BT/PR10324/MED/29/808/2013//Department of Biotechnology , Ministry of Science and Technology/ ; }, abstract = {Candida albicans, the dimorphic opportunistic human fungal pathogen, is capable of forming highly drug-resistant biofilms in the human host. Formation of biofilm is a multistep and multiregulatory process involving various adaptive mechanisms. The ability of cells in a biofilm to alter membrane lipid composition is one such adaptation crucial for biofilm development in C. albicans. Lipids modulate mixed species biofilm formation in vivo and inherent antifungal resistance associated with these organized communities. Cells in C. albicans biofilms display phase-dependent changes in phospholipid classes and in levels of lipid raft formation. Systematic studies with genetically modified strains in which the membrane phospholipid composition can be manipulated are limited in C. albicans. In this review, we summarize the knowledge accumulated on the impact that alterations in phospholipids may have on the biofilm forming ability of C. albicans in the human host. This review may provide the requisite impetus to analyze lipids from a therapeutic standpoint in managing C. albicans biofilms.}, } @article {pmid30566029, year = {2019}, author = {Kim, SI and Yoon, H}, title = {Roles of YcfR in Biofilm Formation in Salmonella Typhimurium ATCC 14028.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {32}, number = {6}, pages = {708-716}, doi = {10.1094/MPMI-06-18-0166-R}, pmid = {30566029}, issn = {0894-0282}, mesh = {*Bacterial Outer Membrane Proteins/genetics ; *Biofilms ; Humans ; *Plants/microbiology ; *Salmonella typhimurium/genetics ; }, abstract = {An increasing number of foodborne diseases are currently attributable to farm produce contaminated with enteric pathogens such as Salmonella enterica. Recent studies have shown that a variety of enteric pathogens are able to colonize plant surfaces by forming biofilms and thereby persist for long periods, which can subsequently lead to human infections. Therefore, biofilm formation by enteric pathogens on plants poses a risk to human health. Here, we deciphered the roles of YcfR in biofilm formation by Salmonella enterica. YcfR is a putative outer membrane protein associated with bacterial stress responses. The lack of YcfR facilitated the formation of multicellular aggregates on cabbage leaves as well as glass surfaces while reducing bacterial motility. ycfR deletion caused extensive structural alterations in the outer membrane, primarily in lipopolysaccharides, outer membrane proteins, cellulose, and curli fimbria, thereby increasing cell surface hydrophobicity. However, the absence of YcfR rendered Salmonella susceptible to stressful treatments, despite the increased multicellular aggregation. These results suggest that YcfR is an essential constituent of Salmonella outer membrane architecture and its absence may cause multifaceted structural changes, thereby compromising bacterial envelope integrity. In this context, YcfR may be further exploited as a potential target for controlling Salmonella persistence on plants.}, } @article {pmid30565232, year = {2019}, author = {Stone, SJ and Kumar, PS and Offenbacher, S and Heasman, PA and McCracken, GI}, title = {Exploring a temporal relationship between biofilm microbiota and inflammatory mediators during resolution of naturally occurring gingivitis.}, journal = {Journal of periodontology}, volume = {90}, number = {6}, pages = {627-636}, doi = {10.1002/JPER.18-0156}, pmid = {30565232}, issn = {1943-3670}, mesh = {Adult ; Biofilms ; *Dental Plaque ; Gingival Crevicular Fluid ; *Gingivitis ; Humans ; *Microbiota ; }, abstract = {BACKGROUND: This study uses multiple, contemporary methodologies to expand our knowledge of the temporal relationship between host-microbial interactions and clinical signs of gingivitis.

METHODS: Subgingival plaque and crevicular fluid samples were collected from 31 systemically healthy adults with naturally occurring plaque-induced gingivitis. Professional prophylaxis was administered and participants were followed over 7 weeks. Microbial characterization was performed using a bead-based hybridization assay and cytokine analysis using bead-based flow cytometry.

RESULTS: The provision of sequential interventions, oral hygiene instruction, and subsequent professional prophylaxis brought about significant reduction of plaque and resolution of gingivitis at all post baseline time points (P < 0.0001). Candidate cytokines that increased significantly (95% level) were interleukin (IL)-1β, matrix metalloproteinases (MMP)-1, MMP-3, MMP-8, MMP-9, from baseline to week 2; regulated on activation, normal T cell expressed and secreted (RANTES) at week 4 and week 8; macrophage inflammatory protein (MIP)-1α and MIP-1β at week 8. Resolution of inflammation was accompanied by a shift in the microbiological flora toward those species associated with health.

CONCLUSIONS: This study provides further evidence of the dynamic relationships that exist between the overt clinical signs, the microbial biofilm, and the host response in gingivitis and upon resolution following clinical interventions. Understanding the interactions between the host immune system and subgingival microbial communities during the resolution of established gingivitis continues to evolve as additional knowledge is achieved through using new analytical technologies. The present study confirms a critical effect of oral hygiene measures on restoration of microbial eubiosis in subgingival communities, confirming the important role for home care and professional intervention in maintaining oral health.}, } @article {pmid30564205, year = {2018}, author = {Polst, BH and Anlanger, C and Risse-Buhl, U and Larras, F and Hein, T and Weitere, M and Schmitt-Jansen, M}, title = {Hydrodynamics Alter the Tolerance of Autotrophic Biofilm Communities Toward Herbicides.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2884}, pmid = {30564205}, issn = {1664-302X}, abstract = {Multiple stressors pose potential risk to aquatic ecosystems and are the main reasons for failing ecological quality standards. However, mechanisms how multiple stressors act on aquatic community structure and functioning are poorly understood. This is especially true for two important stressors types, hydrodynamic alterations and toxicants. Here we perform a mesocosm experiment in hydraulic flumes connected as a bypass to a natural stream to test the interactive effects of both factors on natural (inoculated from streams water) biofilms. Biofilms, i.e., the community of autotrophic and heterotrophic microorganisms and their extracellular polymeric substances (EPS) in association with substratum, are key players in stream functioning. We hypothesized (i) that the tolerance of biofilms toward toxicants (the herbicide Prometryn) decreases with increasing hydraulic stress. As EPS is known as an absorber of chemicals, we hypothesize (ii) that the EPS to cell ratio correlates with both hydraulic stress and herbicide tolerance. Tolerance values were derived from concentration-response assays. Both, the herbicide tolerance and the biovolume of the EPS significantly correlated with the turbulent kinetic energy (TKE), while the diversity of diatoms (the dominant group within the stream biofilms) increased with flow velocity. This indicates that the positive effect of TKE on community tolerance was mediated by turbulence-induced changes in the EPS biovolume. This conclusion was supported by a second experiment, showing decreasing effects of the herbicide to a diatom biofilm (Nitzschia palea) with increasing content of artificial EPS. We conclude that increasing hydrodynamic forces in streams result in an increasing tolerance of microbial communities toward chemical pollution by changes in EPS-mediated bioavailability of toxicants.}, } @article {pmid30563740, year = {2019}, author = {Wang, C and Zhang, Q and Tang, X and An, Y and Li, S and Xu, H and Li, Y and Wang, X and Luan, W and Wang, Y and Liu, M and Yu, L}, title = {Effects of CwlM on autolysis and biofilm formation in Mycobacterium tuberculosis and Mycobacterium smegmatis.}, journal = {International journal of medical microbiology : IJMM}, volume = {309}, number = {1}, pages = {73-83}, doi = {10.1016/j.ijmm.2018.12.002}, pmid = {30563740}, issn = {1618-0607}, mesh = {Bacterial Proteins/genetics/metabolism ; Bacteriolysis/*genetics ; Base Sequence ; Biofilms/*growth & development ; Cell Wall/metabolism ; Humans ; Mycobacterium Infections, Nontuberculous/microbiology ; Mycobacterium smegmatis/enzymology/*genetics ; Mycobacterium tuberculosis/enzymology/*genetics ; N-Acetylmuramoyl-L-alanine Amidase/genetics/*metabolism ; Recombinant Proteins/genetics/metabolism ; Sequence Deletion ; Tuberculosis/microbiology ; }, abstract = {Tuberculosis is a highly infectious disease and of high incidence in low-income countries that is caused by Mycobacterium tuberculosis (M. tuberculosis). M. tuberculosis can form biofilms in vitro and in vivo, and the cells in the biofilm can survive at high concentrations of antibiotics. CwlM is a peptidoglycan hydrolase (amidase) and can hydrolyze bacterial cell walls, and the effects of CwlM on autolysis and biofilms is worthy of in-depth study. In this study, we successfully constructed an in vitro biofilm model of M. tuberculosis and Mycobacterium smegmatis (M. smegmatis). Reverse transcription followed by real-time quantitative PCR (qPCR) revealed that the expression of cwlM in M. tuberculosis and M. smegmatis was significantly up-regulated during the middle stage of biofilm formation. Treatment with recombinant CwlM enhanced the autolytic ability of M. tuberculosis and M. smegmatis and reduced the formation of their biofilms. As M. smegmatis is a model bacterium of M. tuberculosis, we built the M. smegmatis cwlM-deletion strain MSΔ6935, whose autolytic ability, biofilm production, and eDNA and eRNA content were determined to be lower than those of its parental strain. In conclusion, the cwlM gene plays a key regulatory role in biofilm formation in M. tuberculosis and M. smegmatis. This study provided a theoretical basis for using peptidoglycan hydrolase as a target for the inhibition of biofilms.}, } @article {pmid30563307, year = {2018}, author = {Dua, K and Gupta, G and Chellapan, DK and Bebawy, M and Collet, T}, title = {Nanoparticle-based therapies as a modality in treating wounds and preventing biofilm.}, journal = {Panminerva medica}, volume = {60}, number = {4}, pages = {237-238}, doi = {10.23736/S0031-0808.18.03435-3}, pmid = {30563307}, issn = {1827-1898}, mesh = {Anti-Bacterial Agents/administration & dosage ; *Biofilms ; Drug Delivery Systems ; Emulsions ; Escherichia coli ; Fibroblasts/metabolism ; Gels ; Humans ; Metal Nanoparticles ; Nanoparticles/*therapeutic use ; Ointments ; Pseudomonas aeruginosa ; Skin/metabolism ; Staphylococcus aureus ; Tissue Engineering ; *Wound Healing ; Wounds and Injuries/*therapy ; }, } @article {pmid30563297, year = {2018}, author = {Toma, S and Behets, C and Brecx, MC and Lasserre, JF}, title = {In Vitro Comparison of the Efficacy of Peri-Implantitis Treatments on the Removal and Recolonization of Streptococcus gordonii Biofilm on Titanium Disks.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {30563297}, issn = {1996-1944}, abstract = {Objective: To compare the efficacy of four commonly used clinical procedures in removing Streptococcus gordonii biofilms from titanium disks, and the recolonization of the treated surfaces. Background: Successful peri-implantitis treatment depends on the removal of the dental biofilm. Biofilm that forms after implant debridement may threaten the success of the treatment and the long-term stability of the implants. Methods: S. gordonii biofilms were grown on titanium disks for 48 h and removed using a plastic curette, air-abrasive device (Perio-Flow®), titanium brush (TiBrush®), or implantoplasty. The remaining biofilm and the recolonization of the treated disks were observed using scanning electron microscopy and quantified after staining with crystal violet. Surface roughness (Ra and Rz) was measured using a profilometer. Results: S. gordonii biofilm biomass was reduced after treatment with Perio-Flow®, TiBrush®, and implantoplasty (all p < 0.05), but not plastic curette (p > 0.05), compared to the control group. Recolonization of S. gordonii after treatment was lowest after Perio-Flow®, TiBrush®, and implantoplasty (all p < 0.05 vs. control), but there was no difference between the plastic curette and the control group (p > 0.05). Ra and Rz values ranged from 1[-]6 µm to 1[-]2 µm and did not differ statistically between the control, plastic curette, Perio-Flow, and TiBrush groups. However, the implantoplasty group showed a Ra value below 1 µm (p < 0.01, ANOVA, Tukey). Conclusions: Perio-Flow[®], TiBrush[®], and implantoplasty were more effective than the plastic curette at removing the S. gordonii biofilm and preventing recolonization. These results should influence the surgical management of peri-implantitis.}, } @article {pmid30561496, year = {2019}, author = {Deva, AK}, title = {Commentary on: Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?.}, journal = {Aesthetic surgery journal}, volume = {39}, number = {8}, pages = {860-862}, doi = {10.1093/asj/sjy313}, pmid = {30561496}, issn = {1527-330X}, mesh = {*Anti-Infective Agents, Local ; Biofilms ; *Breast Implantation ; *Contracture ; Humans ; Implant Capsular Contracture ; }, } @article {pmid30560366, year = {2019}, author = {Silva, PLAPA and Goulart, LR and Reis, TFM and Mendonça, EP and Melo, RT and Penha, VAS and Peres, PABM and Hoepers, PG and Beletti, ME and Fonseca, BB}, title = {Biofilm Formation in Different Salmonella Serotypes Isolated from Poultry.}, journal = {Current microbiology}, volume = {76}, number = {1}, pages = {124-129}, pmid = {30560366}, issn = {1432-0991}, support = {APQ03613-17//Fundação de Amparo à Pesquisa do Estado de Minas Gerais/ ; 465669/2014-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Animals ; Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Egg Shell/microbiology ; Farms ; Food Microbiology ; Poultry/*microbiology ; Salmonella/*classification/*growth & development ; Salmonella Infections, Animal/*microbiology ; }, abstract = {Little is known about Salmonella biofilm assembly, making the prevention of the disease a challenge in the poultry production chain. The objective of the present study was then to evaluate biofilm formation from different serotypes of Salmonella spp. in both polystyrene plates and eggshells. Salmonella Gallinarum and S. Minnesota were both classified as producers of biofilms of moderate intensity. Interestingly, S. Gallinarum produces biofilm even though being a serotype without flagellum and not having the lux gene in its genome, suggesting that there might be other important structures and genes associated with biofilm formation. Regarding Enteritidis, Typhimurium, Typhimurium variant, and Heidelberg serotypes, despite having high counts, BFI (Biofilm Formation Index) showed low biofilm production, probably due to the scarcity of extracellular matrix produced by such strains. A turkey eggshell model was then used for S. Enteritidis and S. Heidelberg biofilm formation. The results from the microbial count and scanning electron microscopy showed that Salmonella serotypes were also able to generate biofilm in eggshells, suggesting the presence of biofilms in poultry producing farms, a main concern for the poultry production industry.}, } @article {pmid30559726, year = {2018}, author = {Wang, T and Shao, J and Da, W and Li, Q and Shi, G and Wu, D and Wang, C}, title = {Strong Synergism of Palmatine and Fluconazole/Itraconazole Against Planktonic and Biofilm Cells of Candida Species and Efflux-Associated Antifungal Mechanism.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2892}, pmid = {30559726}, issn = {1664-302X}, abstract = {Fungal infections caused by Candida albicans and non-albicans Candida [NAC] species are becoming a growing threat in immunodeficient population, people with long-term antibiotic treatment and patients enduring kinds of catheter intervention. The resistance to one or more than one conventional antifungal agents contributes greatly to the widespread propagation of Candida infections. The severity of fungal infection requires the discovery of novel antimycotics and the extensive application of combination strategy. In this study, a group of Candida standard and clinical strains including C. albicans as well as several NAC species were employed to evaluate the antifungal potentials of palmatine (PAL) alone and in combination with fluconazole (FLC)/itraconazole (ITR) by microdilution method, checkerboard assay, gram staining, spot assay, and rhodamine 6G efflux test. Subsequently, the expressions of transporter-related genes, namely CDR1, CDR2, MDR1, and FLU1 for C. albicans, CDR1 and MDR1 for Candida tropicalis and Candida parapsilosis, ABC1 and ABC2 for Candida krusei, CDR1, CDR2, and SNQ2 for Candida glabrata were analyzed by qRT-PCR. The susceptibility test showed that PAL presented strong synergism with FLC and ITR with fractional inhibitory concentration index (FICI) in a range of 0.0049-0.75 for PAL+FLC and 0.0059-0.3125 for PAL+ITR in planktonic cells, 0.125-0.375 for PAL+FLC and 0.0938-0.3125 for PAL+ITR in biofilms. The susceptibility results were also confirmed by gram staining and spot assay. After combinations, a vast quantity of rhodamine 6G could not be pumped out as considerably intracellular red fluorescence was accumulated. Meanwhile, the expressions of efflux-associated genes were evaluated and presented varying degrees of inhibition. These results indicated that PAL was a decent antifungal synergist to promote the antifungal efficacy of azoles (such as FLC and ITR), and the underlying antifungal mechanism might be linked with the inhibition of efflux pumps and the elevation of intracellular drug content.}, } @article {pmid30559713, year = {2018}, author = {Di Domenico, EG and Cavallo, I and Bordignon, V and D'Agosto, G and Pontone, M and Trento, E and Gallo, MT and Prignano, G and Pimpinelli, F and Toma, L and Ensoli, F}, title = {The Emerging Role of Microbial Biofilm in Lyme Neuroborreliosis.}, journal = {Frontiers in neurology}, volume = {9}, number = {}, pages = {1048}, pmid = {30559713}, issn = {1664-2295}, abstract = {Lyme borreliosis (LB) is the most common tick-borne disease caused by the spirochete Borrelia burgdorferi in North America and Borrelia afzelii or Borrelia garinii in Europe and Asia, respectively. The infection affects multiple organ systems, including the skin, joints, and the nervous system. Lyme neuroborreliosis (LNB) is the most dangerous manifestation of Lyme disease, occurring in 10-15% of infected individuals. During the course of the infection, bacteria migrate through the host tissues altering the coagulation and fibrinolysis pathways and the immune response, reaching the central nervous system (CNS) within 2 weeks after the bite of an infected tick. The early treatment with oral antimicrobials is effective in the majority of patients with LNB. Nevertheless, persistent forms of LNB are relatively common, despite targeted antibiotic therapy. It has been observed that the antibiotic resistance and the reoccurrence of Lyme disease are associated with biofilm-like aggregates in B. burgdorferi, B. afzelii, and B. garinii, both in vitro and in vivo, allowing Borrelia spp. to resist to adverse environmental conditions. Indeed, the increased tolerance to antibiotics described in the persisting forms of Borrelia spp., is strongly reminiscent of biofilm growing bacteria, suggesting a possible role of biofilm aggregates in the development of the different manifestations of Lyme disease including LNB.}, } @article {pmid30559386, year = {2018}, author = {Tabassum, R and Shafique, M and Khawaja, KA and Alvi, IA and Rehman, Y and Sheik, CS and Abbas, Z and Rehman, SU}, title = {Complete genome analysis of a Siphoviridae phage TSK1 showing biofilm removal potential against Klebsiella pneumoniae.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {17904}, pmid = {30559386}, issn = {2045-2322}, support = {4501//Higher Education Commission, Pakistan (HEC)/International ; 4501//Higher Education Commission, Pakistan (HEC)/International ; 4501//Higher Education Commission, Pakistan (HEC)/International ; 4501//Higher Education Commission, Pakistan (HEC)/International ; 4501//Alabama Commission on Higher Education/International ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteriophages/*genetics ; Base Composition/genetics ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial/drug effects/genetics ; Genome, Viral/*genetics ; Host Specificity/genetics ; Klebsiella pneumoniae/drug effects/*virology ; Open Reading Frames/genetics ; Phylogeny ; Siphoviridae/*genetics ; }, abstract = {Multidrug-resistant Klebsiella pneumoniae is a nosocomial pathogen, produces septicemia, pneumonia and UTI. Excessive use of antibiotics contributes towards emergence of multidrug-resistance. Bacteriophage-therapy is a potential substitute of antibiotics with many advantages. In this investigation, microbiological and genome characterization of TSK1 bacteriophage and its biofilm elimination capability are presented. TSK1 showed narrow host range and highest stability at pH 7 and 37 °C. TSK1 reduced the growth of K. pneumoniae during the initial 14 hours of infection. Post-treatment with TSK1 against different age K. pneumoniae biofilms reduced 85-100% biomass. Pre-treatment of TSK1 bacteriophage against the biofilm of Klebsiella pneumoniae reduced > 99% biomass in initial 24 hr of incubation. The genome of TSK1 phage comprised 49,836 base pairs with GC composition of 50.44%. Total seventy-five open reading frames (ORFs) were predicted, 25 showed homology with known functional proteins, while 50 were called hypothetical, as no homologs with proved function exists in the genome databases. Blast and phylogenetic analysis put it in the Kp36 virus genus of family Siphoviridae. Proposed packaging strategy of TSK1 bacteriophage genome is headful packaging using the pac sites. The potential of TSK1 bacteriophage could be used to reduce the bacterial load and biofilm in clinical and non-clinical settings.}, } @article {pmid30558705, year = {2018}, author = {Chen, L and Qiu, Y and Tang, H and Hu, LF and Yang, WH and Zhu, XJ and Huang, XX and Wang, T and Zhang, YQ}, title = {ToxR Is Required for Biofilm Formation and Motility of Vibrio Parahaemolyticus.}, journal = {Biomedical and environmental sciences : BES}, volume = {31}, number = {11}, pages = {848-850}, doi = {10.3967/bes2018.112}, pmid = {30558705}, issn = {0895-3988}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; DNA-Binding Proteins/genetics/*metabolism ; Flagella/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Transcription Factors/genetics/*metabolism ; Vibrio parahaemolyticus/cytology/genetics/growth & development/*physiology ; }, } @article {pmid30557752, year = {2019}, author = {Meng, J and Li, J and He, J and Li, J and Deng, K and Nan, J}, title = {Nutrient removal from high ammonium swine wastewater in upflow microaerobic biofilm reactor suffered high hydraulic load.}, journal = {Journal of environmental management}, volume = {233}, number = {}, pages = {69-75}, doi = {10.1016/j.jenvman.2018.12.027}, pmid = {30557752}, issn = {1095-8630}, mesh = {*Ammonium Compounds ; Animals ; Biofilms ; Bioreactors ; Nitrogen ; Nutrients ; Swine ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {To understand the ability of an upflow microaerobic biofilm reactor (UMBR) to remove nutrient from manure-free swine wastewater rich in NH4[+] with a COD/TN ratio less than 1.00, effect of hydraulic loading rate (HLR) on the microaerobic process was evaluated with a constant reflux ratio of 25 at 25 °C. The results showed that changes in HLR had a remarkable effect on the performance of the UMBR in nutrient removal from the wastewater. With the favorable HLR 3.0 m[3]/(m[3]·d) (Hydraulic Retention Time (HRT) 8 h), average removal of COD, NH4[+] and TN in the microaerobic process reached 59.3%, 87.7% and 84.7%, respectively, though the COD/TN ratio was as low as 0.84. With an over HLR of 4.0 m[3]/(m[3]·d) (HRT decreased to 6 h), bad performance of the UMBR was observed with an average removal of COD, NH4[+] and TN as low as 45.0%, 59.0% and 57.5%, respectively. Since the HLR was decreased to 2.4 m[3]/(m[3]·d) (HRT 10 h), the microaerobic process regained the efficiency in nutrient removal with a removal of COD, NH4[+] and TN averaged 59.0%, 95.3% and 87.8%, respectively. The microaerobic condition allowed anammox bacteria, ammonia-oxidizing bacteria and archaea, nitrite-oxidizing bacteria and denitrifiers to all thrive in the UMBR, resulting in the efficient synchronous removal of organic carbon and nitrogen. As the dominant approach to nitrogen removal, anaerobic ammonium oxidation (anammox) pathway contributing to the TN removal in the microaerobic process exceeded 59.5% at HLR 3.0 m[3]/(m[3]·d). The results demonstrated that the UMBR can remove nitrogen and carbon from swine wastewater, with a suitable HLR.}, } @article {pmid30557585, year = {2019}, author = {Sengan, M and Subramaniyan, SB and Arul Prakash, S and Kamlekar, R and Veerappan, A}, title = {Effective elimination of biofilm formed with waterborne pathogens using copper nanoparticles.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {341-346}, doi = {10.1016/j.micpath.2018.12.025}, pmid = {30557585}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Copper/*pharmacology ; Gram-Negative Bacteria/*drug effects/isolation & purification/physiology ; Metal Nanoparticles/*chemistry/*ultrastructure ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy ; Surface Plasmon Resonance ; *Water Microbiology ; X-Ray Diffraction ; }, abstract = {In this paper, the self assembling properties of taurolipids were used to prepare stable copper nanoparticles (CuNPs), and demonstrated the ability of CuNPs to eradicate the biofilms formed by waterborne pathogens. The synthesized CuNPs display wine red color and exhibited surface plasmon resonance with a maximum at 590 nm. Transmission electron microscopy showed that the CuNPs are well-dispersed with spherical morphology and the size range between 5 and 12 nm. The powder X-ray diffraction study revealed that the CuNPs was free from copper oxide impurities and crystalline with the face centered cubic structure. The CuNPs exhibited excellent anti-biofilm activity against water borne pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Shigella flexneri. Light microscopy and scanning electron microscopy (SEM) study revealed that CuNPs eliminates the mature biofilm at the minimum biofilm eradication concentration of 12.5 μM. The antimicrobial activity of the CuNPs was observed at the minimum inhibitory concentration of 25 μM, indicating the reported CuNPs exhibit true anti-biofilm effect. Fluorescence microscopy and SEM study proved that CuNPs kills the bacteria through membrane damage. The possibility to use CuNPs in cleaning biofilm formed on storage containers was demonstrated through removing the mature biofilm formed on a glass pipe.}, } @article {pmid30554320, year = {2019}, author = {Truu, M and Oopkaup, K and Krustok, I and Kõiv-Vainik, M and Nõlvak, H and Truu, J}, title = {Bacterial community activity and dynamics in the biofilm of an experimental hybrid wetland system treating greywater.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {4}, pages = {4013-4026}, pmid = {30554320}, issn = {1614-7499}, support = {232274//FP7 International Cooperation/ ; PUT1125//Eesti Teadusfondi/ ; IUT13016//Eesti Teadusagentuur/ ; }, mesh = {Ammonia/chemistry/metabolism ; Bacteria/genetics/*metabolism ; Biofilms ; Denitrification ; Microbial Consortia/genetics/*physiology ; Nitrification ; Nitrogen/metabolism ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid/instrumentation/*methods ; *Wetlands ; }, abstract = {The objectives of this study were to determine the biofilm microbial activity and bacterial community structure and successions in greywater treatment filters and to relate the treatment efficiency to the bacterial community parameters. This 10-month study was performed in a newly established experimental system for domestic greywater treatment that consisted of three parallel vertical flow filters (VFs) followed by a horizontal flow filter (HF). A rapid increase in the bacterial community abundance occurred during the first 85 days of filter operations, followed by a short-term decrease and the stabilization of the 16S rRNA gene copy numbers at average levels of 1.2 × 10[9] and 3.2 × 10[8] copies/g dw in VFs and HF, respectively, until the end of the experiment. The dominant bacterial phyla and genera differed between the VFs and HF. The temporal variation in the bacterial community structure was primarily related to the species replacement, and it was significantly affected by the influent organic carbon and nitrogen compounds in the VFs and the ammonia and organic carbon in the HF filters. Despite the differences in the community structure and assembly mechanisms, the temporal dynamics of the bacterial community showed high congruence between the filter types. The treatment efficiency was related to the biofilm bacterial community diversity and abundance and the abundance of certain bacterial genera in the VF filters. The results suggest that the dominant pathway of nitrogen removal by greywater treatment VFs occurs via coupled heterotrophic nitrification and denitrification, while the contribution of aerobic denitrification is temporally variable in these filters.}, } @article {pmid30553340, year = {2019}, author = {Liu, Y and Jiang, Y and Zhu, J and Huang, J and Zhang, H}, title = {Inhibition of bacterial adhesion and biofilm formation of sulfonated chitosan against Pseudomonas aeruginosa.}, journal = {Carbohydrate polymers}, volume = {206}, number = {}, pages = {412-419}, doi = {10.1016/j.carbpol.2018.11.015}, pmid = {30553340}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Chitosan/*analogs & derivatives/chemical synthesis/*pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/physiology ; Sulfonic Acids/chemical synthesis/pharmacology ; }, abstract = {The exploitation of chitosan derivatives as safe and natural polymers against microorganisms has been reconsidered as an alternative to antibiotics and chemical preservatives. Herein, inhibition of bacterial adhesion and biofilm formation by anionic chitosan (sulfonated chitosan, SCS) and cationic chitosan (chitosan hydrochloride, WCS) against P. aeruginosa were investigated. The results showed SCS exhibited good antibacterial activity with 1 mg/mL MIC and 8 mg/mL MBC, while MIC and MBC of WCS were 1 mg/mL and 16 mg/mL, respectively. The metabolic activity and secretion of exopolysaccharide in biofilm of P. aeruginosa were significantly decreased after the treatment with SCS. Scanning electron microscopy and confocal laser scanning microscopy further demonstrated that SCS and WCS could significantly inhibit the biofilm formation in a concentration-dependent mode. Overall, these results suggest that WCS and SCS are useful to inhibit the biofilm formation of P. aeruginosa, and would be potential alternatives for the control of bacterial pathogens in food industry.}, } @article {pmid30552189, year = {2019}, author = {Xu, Z and Zhang, H and Sun, X and Liu, Y and Yan, W and Xun, W and Shen, Q and Zhang, R}, title = {Bacillus velezensis Wall Teichoic Acids Are Required for Biofilm Formation and Root Colonization.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {5}, pages = {}, pmid = {30552189}, issn = {1098-5336}, mesh = {Bacillus/genetics/*metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/*growth & development ; Cucumis sativus/microbiology ; Culture Media/chemistry ; Mutation ; Plant Roots/*microbiology ; Polysaccharides/metabolism ; Proteomics ; Rhizosphere ; Teichoic Acids/genetics/*metabolism/*pharmacology ; }, abstract = {Rhizosphere colonization by plant growth-promoting rhizobacteria (PGPR) along plant roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the root colonization process by plant-beneficial Bacillus strains is essential for the use of these strains in agriculture. Here, we observed that an sfp gene mutant of the plant growth-promoting rhizobacterium Bacillus velezensis SQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δsfp mutant, and impairment of the ggaA gene postponed biofilm formation and decreased cucumber root colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and root colonization. The deficiency in biofilm formation of the ΔgtaB mutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the root colonization process by a plant-beneficial Bacillus strain, which will help improve its application as a biofertilizer.IMPORTANCEBacillus velezensis is a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally, Bacillus spp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in root colonization by plant-beneficial Bacillus strains remain largely unknown. Here, we showed that WTAs play important roles in the plant root colonization process. The loss of the gtaB gene affects the ability of B. velezensis SQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and colonization in the rhizosphere. This knowledge provides new insights into the Bacillus root colonization process and can help improve our understanding of plant-rhizobacterium interactions.}, } @article {pmid30551102, year = {2019}, author = {Lin, XQ and Li, ZL and Liang, B and Nan, J and Wang, AJ}, title = {Identification of biofilm formation and exoelectrogenic population structure and function with graphene/polyanliline modified anode in microbial fuel cell.}, journal = {Chemosphere}, volume = {219}, number = {}, pages = {358-364}, doi = {10.1016/j.chemosphere.2018.11.212}, pmid = {30551102}, issn = {1879-1298}, mesh = {Aniline Compounds/chemistry ; Bacteria/metabolism ; Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Carbon/metabolism ; *Electrodes ; Geobacter/metabolism ; Graphite/chemistry ; Wastewater/chemistry ; }, abstract = {Improving anode configuration with polymer or nanomaterial modification is promising for enhancing microbial fuel cell performance. However, how anode modification affects biofilm development and electrogenic function remains poorly understood. In this study, the carbon cloth anode modified with polyaniline and reduced graphene oxide was successfully fabricated which obtained the highest power output. Accelerated electrogenic biofilm formation and the better electrogenic bacterial colonization based on the superior material properties (preferable electrochemical characteristics, the film-like structure and the more activated sites) were observed with the in situ biofilm development monitoring. The acclimation time was 2.4 times shorter with graphene and polyaniline modified anode than the bare one when inoculated with wastewater. Biofilm structure and function analysis show that Geobacter is the most predominant with the abundance as high as 81.4%, and meanwhile, electrogenesis related outer-surface octaheme c-type cytochrome omcZ is highly expressed in the modified anode. The anode modified with graphene and polyaniline favors Geobacter colonization, accelerates electrogenic biofilm formation and improves omcZ expression level, eventually leading to the improved performance of microbial fuel cell. The study for the first time reveals the impacts on biofilm development and microbial function by anode modification, which will better guide the potential application of microbial fuel cell for wastewater recovery.}, } @article {pmid30551043, year = {2019}, author = {Li, X and Zeng, C and Lu, Y and Liu, G and Luo, H and Zhang, R}, title = {Development of methanogens within cathodic biofilm in the single-chamber microbial electrolysis cell.}, journal = {Bioresource technology}, volume = {274}, number = {}, pages = {403-409}, doi = {10.1016/j.biortech.2018.12.002}, pmid = {30551043}, issn = {1873-2976}, mesh = {Bioelectric Energy Sources ; *Biofilms ; Electrodes ; Electrolysis ; Hydrogen/metabolism ; Methane/*biosynthesis ; Methanobacteriaceae/*metabolism ; Microbiota ; }, abstract = {The aim of this study was to investigate the development of cathodic biofilm and its effect on methane production in a single-chamber microbial electrolysis cell (MEC). The MEC with 1 g/L acetate was successfully operated within 31 cycles (∼2400 h). The maximum methane production rate and average current capture efficiency in the MEC reached 93 L/m[3]·d and 82%, respectively. Distinct stratification of Methanobacteriaceae within cathodic biofilm was observed after 9 cycles of operation. The relative abundance of Methanobacteriaceae in the microbial community increased from 45.3% (0-15 μm), 57.6% (15-30 μm), 66.9% (30-45 μm) to 77.2% (45-60 μm) within the cathodic biofilm. The methane production rates were positively correlated with the mcrA gene copy numbers in the cathodic biofilm. Our results should be useful to understand the mechanism of methane and hydrogen production in the MEC.}, } @article {pmid30550233, year = {2018}, author = {Kwiecińska-Piróg, J and Skowron, K and Gospodarek-Komkowska, E}, title = {Primary and Secondary Bacteremia Caused by Proteus spp.: Epidemiology, Strains Susceptibility and Biofilm Formation.}, journal = {Polish journal of microbiology}, volume = {67}, number = {4}, pages = {471-478}, pmid = {30550233}, issn = {1733-1331}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*pharmacology ; Bacteremia/*epidemiology/microbiology ; Biofilms/*growth & development ; Child ; Coinfection/blood/*epidemiology ; DNA, Bacterial/genetics ; Female ; Hospitals ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Phenotype ; Piperacillin/pharmacology ; Poland/epidemiology ; Proteus/*drug effects/genetics ; Proteus Infections/blood/*epidemiology ; Retrospective Studies ; Tazobactam/pharmacology ; Urinary Tract Infections/epidemiology/microbiology ; Young Adult ; }, abstract = {Proteus spp. is an etiological factor of urinary tract and bloodstream infections. The aim of this study was the retrospective analysis of susceptibility of Proteus spp. strains isolated from bloodstream infections (BSIs) as well as similarity evaluation of the strains isolated from different clinical samples. Proteus spp. strains were isolated in 2009-2017 from hospital patients. Identification was based on the colony's morphology and biochemical or MALDI-TOF MS analyzes. The antibiotic susceptibility test was done using the diffusion method. Biofilm formation was evaluated with microplate method using TTC. Bacteremia caused by Proteus spp. was found in 97 patients, mainly secondary to urinary tract infection. Most of the strains were susceptible to piperacillin with tazobactam (95.9%) and amikacin (86.7%). Elderly patients have a higher risk of mortality after BSIs caused by Proteus spp. A detailed analysis was made for randomly chosen 26 strains isolated from 11 patients with Proteus mirabilis bacteremia. Using PFGE, we found that 10 (90.9%) isolates, collected from different clinical specimens of the same patient, were genetically identical. Proteus spp. is an etiological factor of urinary tract and bloodstream infections. The aim of this study was the retrospective analysis of susceptibility of Proteus spp. strains isolated from bloodstream infections (BSIs) as well as similarity evaluation of the strains isolated from different clinical samples. Proteus spp. strains were isolated in 2009–2017 from hospital patients. Identification was based on the colony’s morphology and biochemical or MALDI-TOF MS analyzes. The antibiotic susceptibility test was done using the diffusion method. Biofilm formation was evaluated with microplate method using TTC. Bacteremia caused by Proteus spp. was found in 97 patients, mainly secondary to urinary tract infection. Most of the strains were susceptible to piperacillin with tazobactam (95.9%) and amikacin (86.7%). Elderly patients have a higher risk of mortality after BSIs caused by Proteus spp. A detailed analysis was made for randomly chosen 26 strains isolated from 11 patients with Proteus mirabilis bacteremia. Using PFGE, we found that 10 (90.9%) isolates, collected from different clinical specimens of the same patient, were genetically identical.}, } @article {pmid30550129, year = {2018}, author = {Li, H and Sun, XC and Liu, Q and Li, YQ and Hu, L and Yu, HP and Wang, DH}, title = {[Involvement of Th17/Treg imbalance in bacterial biofilm induced chronic rhinosinusitis].}, journal = {Lin chuang er bi yan hou tou jing wai ke za zhi = Journal of clinical otorhinolaryngology, head, and neck surgery}, volume = {32}, number = {24}, pages = {1870-1875}, doi = {10.13201/j.issn.1001-1781.2018.24.006}, pmid = {30550129}, issn = {2096-7993}, abstract = {Objective:The aim of this study is to investigate the involvement of Th17/Treg imbalance in the pathogenesis of bacterial biofilm (BBF) induced chronic rhinosinusitis(CRS). Method:CRS nasal sinus mucosa was collected, and BBF was examined by BacLight/CSLM detection. Forty CRS cases(20 BBF positive cases and 20 negative cases) and 10 controls were enrolled. Clinical data were recorded before operation, and nasal sinus mucosa was collected during operation. The mRNA level of Forkhead box protein 3(Foxp3), retinoid-related orphan nuclear receptor γt (RORγt), and IL-17 were detected by Real-time PCR. The differences between CRS and controls, as well as BBF positive and BBF negative group were analyzed. Correlation analysis was conducted to study the relationship between gene expression. Result:The Foxp3 mRNA was decreased in the CRS group compared with the control group (P<0.05), suggesting that the function of Treg cells was weakened. there was no difference in the mRNA level of IL-17 and RORγt between the two groups (P>0.05). Compared with the BBF-negative group, the Foxp3 mRNA was decreased and the IL-17 mRNA was increased in the BBF-positive group (?)(P<0.05), (?)suggesting that Th17 cells function enhanced and Treg cells function decreased. The mRNA level of RORγt showed no difference (P>0.05). The mRNA level of Foxp3 and IL-17 was negatively correlated (?)(r=-0.283,(?)P<0.05). Conclusion:The imbalance of Th17/Treg in sinus mucosa caused by BBF may play an important role in CRS.}, } @article {pmid30549304, year = {2019}, author = {Cai, W and Willmon, E and Burgos, FA and Ray, CL and Hanson, T and Arias, CR}, title = {Biofilm and Sediment are Major Reservoirs of Virulent Aeromonas hydrophila (vAh) in Catfish Production Ponds.}, journal = {Journal of aquatic animal health}, volume = {31}, number = {1}, pages = {112-120}, doi = {10.1002/aah.10056}, pmid = {30549304}, issn = {1548-8667}, mesh = {Aeromonas hydrophila/*isolation & purification/pathogenicity/physiology ; Alabama ; Animals ; *Aquaculture ; *Biofilms ; Catfishes/*growth & development ; Geologic Sediments/*microbiology ; Ponds/*microbiology ; Virulence ; }, abstract = {The genus Aeromonas comprises more than 60 recognized species that include many important fish pathogens such as the causative agents of furunculosis and motile Aeromonas septicemia (MAS). Although MAS is typically considered a secondary infection, a new virulent A. hydrophila (vAh) strain has been causing devastating losses to the catfish industry in Alabama since 2009. The objective of this study was to characterize the spatiotemporal distribution of Aeromonas sp. and, specifically, vAh in a commercial catfish farm in western Alabama. We sampled biofilm, sediment, and water from three ponds during four consecutive months during the growing season. Total aerobic counts were between 8.8 × 10[5] and 1.5 × 10[6] CFU/mL but were significantly higher in biofilm and sediment than in water throughout the sampling period. Total Aeromonas counts in water samples significantly increased in all three ponds after the month of August and ranged from 7.8 × 10[3] to 4.9 × 10[4] CFU/mL. A similar trend was observed in biofilm and sediment samples for which total Aeromonas counts increased in samples taken in late summer to early fall. Over time, the concentration of Aeromonas in water samples decreased by one order of magnitude, while there was a significant increase in sediments as temperature dropped. The virulent vAh was detected in 35.4% of biofilm samples and 22.9% of sediment samples, suggesting that both environments serve as the major reservoir for this pathogen. Future monitoring efforts should focus on targeting sediment and biofilms since samples of these appear to naturally enrich for the presence of vAh and other Aeromonas species.}, } @article {pmid30548239, year = {2019}, author = {Candela, T and Fagerlund, A and Buisson, C and Gilois, N and Kolstø, AB and Økstad, OA and Aymerich, S and Nielsen-Leroux, C and Lereclus, D and Gohar, M}, title = {CalY is a major virulence factor and a biofilm matrix protein.}, journal = {Molecular microbiology}, volume = {111}, number = {6}, pages = {1416-1429}, doi = {10.1111/mmi.14184}, pmid = {30548239}, issn = {1365-2958}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Animals ; Bacillus thuringiensis/enzymology/*genetics ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/genetics/metabolism ; HeLa Cells ; Hemocytes/microbiology ; Humans ; Larva/microbiology ; Metalloproteases/genetics/*metabolism ; Moths/microbiology ; Virulence Factors/genetics/*metabolism ; }, abstract = {The extracellular biofilm matrix often contains a network of amyloid fibers which, in the human opportunistic pathogen Bacillus cereus, includes the two homologous proteins TasA and CalY. We show here, in the closely related entomopathogenic species Bacillus thuringiensis, that CalY also displays a second function. In the early stationary phase of planktonic cultures, CalY was located at the bacterial cell-surface, as shown by immunodetection. Deletion of calY revealed that this protein plays a major role in adhesion to HeLa epithelial cells, to the insect Galleria mellonella hemocytes and in the bacterial virulence against larvae of this insect, suggesting that CalY is a cell-surface adhesin. In mid-stationary phase and in biofilms, the location of CalY shifted from the cell surface to the extracellular medium, where it was found as fibers. The transcription study and the deletion of sipW suggested that CalY change of location is due to a delayed activity of the SipW signal peptidase. Using purified CalY, we found that the protein polymerization occurred only in the presence of cell-surface components. CalY is, therefore, a bifunctional protein, which switches from a cell-surface adhesin activity in early stationary phase, to the production of fibers in mid-stationary phase and in biofilms.}, } @article {pmid30547194, year = {2019}, author = {Visvalingam, J and Zhang, P and Ells, TC and Yang, X}, title = {Dynamics of Biofilm Formation by Salmonella Typhimurium and Beef Processing Plant Bacteria in Mono- and Dual-Species Cultures.}, journal = {Microbial ecology}, volume = {78}, number = {2}, pages = {375-387}, pmid = {30547194}, issn = {1432-184X}, support = {A-1603 and A-1637//Agriculture and Agri-Food Canada/ ; }, mesh = {Animals ; Bacteria/classification/genetics/*isolation & purification ; Bacterial Physiological Phenomena ; Biodiversity ; *Biofilms ; Cattle ; Food Handling ; Red Meat/analysis/*microbiology ; Salmonella typhimurium/genetics/isolation & purification/*physiology ; }, abstract = {This study aimed to determine the impact of bacteria from a beef plant conveyor belt on the biofilm formation of Salmonella in dual-species cultures. Beef plant isolates (50) including 18 Gram-negative aerobes (GNA), 8 Gram-positive aerobes (GPA), 5 lactic acid bacteria (LAB), 9 Enterobacteriaceae (EB), and 10 generic Escherichia coli (GEC) were included for developing biofilms in mono- and co-culture with S. Typhimurium at 15 °C for 6 days. Five selected cultures in planktonic form and in biofilms were tested for susceptibility to two commonly used sanitizers (i.e. E-San and Perox-E Plus). In mono-cultures, ≥ 80, 67, 61, 20, and 13% of GEC, EB, GNA, LAB, and GPA, respectively, developed measurable biofilms after 2 days, while all co-culture pairings with S. Typhimurium achieved some level of biofilm production. The predominant effect of EB and only effect of GEC strains on the biofilm formation of S. Typhimurium was antagonistic, while that of Gram-positive bacteria was synergistic, with the effect being more prominent on day 6. The effect was highly variable for the GNA isolates. Six aerobic isolates that formed moderate/strong biofilms by day 2 greatly boosted the co-culture biofilm formation. Seven Gram-negative bacteria were antagonistic against the biofilm formation of the co-cultures. Both sanitizers completely inactivated the selected planktonic cultures, but were largely ineffective against biofilms. In conclusion, all beef plant isolates assessed formed biofilms when paired with S. Typhimurium. Aerobic biofilm formers may create a more favorable condition for Salmonella biofilm formation, while some beef plant isolates have potential as a biocontrol strategy for Salmonella biofilms.}, } @article {pmid30547190, year = {2021}, author = {Bachour, Y}, title = {Response to "Bacterial Adhesion and Biofilm Formation on Textured Breast Implant Shell Materials".}, journal = {Aesthetic plastic surgery}, volume = {45}, number = {1}, pages = {353}, pmid = {30547190}, issn = {1432-5241}, mesh = {Bacterial Adhesion ; Biofilms ; *Breast Implantation/adverse effects ; *Breast Implants/adverse effects ; Humans ; Staphylococcus epidermidis ; }, } @article {pmid30545671, year = {2019}, author = {Harris-Ricardo, J and Fang, L and Herrera-Herrera, A and Fortich-Mesa, N and Olier-Castillo, D and Cavanzo-Rojas, D and González-Quintero, R}, title = {Bacterial profile of the supragingival dental biofilm in children with deciduous and early mixed dentition using next generation sequencing (HOMINGS) technique.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {37}, number = {7}, pages = {448-453}, doi = {10.1016/j.eimc.2018.10.019}, pmid = {30545671}, issn = {2529-993X}, mesh = {*Biofilms ; Child ; Child, Preschool ; DNA, Bacterial/genetics/isolation & purification ; DNA, Ribosomal/genetics/isolation & purification ; *Dentition, Mixed ; Female ; Gingiva/*microbiology ; High-Throughput Nucleotide Sequencing/*methods ; Humans ; Male ; *Microbiota ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Ribotyping/*methods ; }, abstract = {OBJECTIVE: Tdescribe the bacterial profile of the supragingival biofilm of children with temporary dentition (CTD) and early mixed dentition (CEMD), with the next-generation sequencing (HOMINGS) technique.

METHOD: A comparative descriptive study was carried out with 30 systemically healthy children aged between 5 and 7 years old from public schools in Cartagena-Colombia. All participants were caries-free applying the criteria of the International Caries Detection and Assessment System (ICDAS II) and had no caries experience according to the Decayed, Missing and Filled Teeth (DMFT) index. Supragingival biofilm samples were collected. Bacterial DNA was extracted and used for analysis using HOMINGS (Human Oral Microbe Identification using Next-Generation Sequencing) based on the sequencing of the V3-V4 region of the 16S rRNA gene using the Illumina MiSeq platform (V3-V4 primers).

RESULTS: A total of 360 species-specific and 65 genus-specific probes were identified. The bacterial genus most predominant in CTD were Streptococcus, Actinomyces, Veillonella and Fusobacterium (29.2% of all bacterial DNA present), while in CEMD the most predominant were Streptococcus, Leptotrichia, TM7 and Porphyromonas (24.5% of all bacterial DNA present). The bacterial species with the highest relative abundance in the oral biofilm microbiome from CTD were Streptococcus sanguinis, Rothia aeria, Gemella haemolysans, while in CEMD they were S. sanguinis, Leptotrichia spp. HOT-417 and Leptotrichia spp. HOT-498. The Shannon diversity index was 2.77 (SD=0.26) for CTD and 3.01 (SD=0.39) for CEMD (P=0.06).

CONCLUSIONS: The analysis of the bacterial profile of the supragingival dental biofilm in children with DMFT, by means of HOMINGS showed low microbiological diversity both in presence and in relative abundance in terms of genus as well as bacterial species.}, } @article {pmid30545317, year = {2018}, author = {Bidossi, A and De Grandi, R and Toscano, M and Bottagisio, M and De Vecchi, E and Gelardi, M and Drago, L}, title = {Probiotics Streptococcus salivarius 24SMB and Streptococcus oralis 89a interfere with biofilm formation of pathogens of the upper respiratory tract.}, journal = {BMC infectious diseases}, volume = {18}, number = {1}, pages = {653}, pmid = {30545317}, issn = {1471-2334}, mesh = {Administration, Intranasal ; Biofilms/*growth & development ; Child ; Humans ; Microbial Interactions/*physiology ; Microbial Sensitivity Tests ; Microbiota/physiology ; Nose/microbiology ; Pharynx/microbiology ; Pilot Projects ; *Probiotics/administration & dosage/pharmacology ; Respiratory Tract Infections/*microbiology/pathology/therapy ; Streptococcus oralis/*physiology ; Streptococcus salivarius/*physiology ; Trachea/microbiology ; }, abstract = {BACKGROUND: Infections of the ears, paranasal sinuses, nose and throat are very common and represent a serious issue for the healthcare system. Bacterial biofilms have been linked to upper respiratory tract infections and antibiotic resistance, raising serious concerns regarding the therapeutic management of such infections. In this context, novel strategies able to fight biofilms may be therapeutically beneficial and offer a valid alternative to conventional antimicrobials. Biofilms consist of mixed microbial communities, which interact with other species in the surroundings and communicate through signaling molecules. These interactions may result in antagonistic effects, which can be exploited in the fight against infections in a sort of "bacteria therapy". Streptococcus salivarius and Streptococcus oralis are α-hemolytic streptococci isolated from the human pharynx of healthy individuals. Several studies on otitis-prone children demonstrated that their intranasal administration is safe and well tolerated and is able to reduce the risk of acute otitis media. The aim of this research is to assess S. salivarius 24SMB and S. oralis 89a for the ability to interfere with biofilm of typical upper respiratory tract pathogens.

METHODS: To investigate if soluble substances secreted by the two streptococci could inhibit biofilm development of the selected pathogenic strains, co-cultures were performed with the use of transwell inserts. Mixed-species biofilms were also produced, in order to evaluate if the inhibition of biofilm formation might require direct contact. Biofilm production was investigated by means of a spectrophotometric assay and by confocal laser scanning microscopy.

RESULTS: We observed that S. salivarius 24SMB and S. oralis 89a are able to inhibit the biofilm formation capacity of selected pathogens and even to disperse their pre-formed biofilms. Diffusible molecules secreted by the two streptococci and lowered pH of the medium revealed to be implied in the mechanisms of anti-biofilm activity.

CONCLUSIONS: S. salivarius 24SMB and S. oralis 89a possess desirable characteristics as probiotic for the treatment and prevention of infections of the upper airways. However, the nature of the inhibition appear to be multifactorial and additional studies are required to get further insights.}, } @article {pmid30545074, year = {2018}, author = {Cattò, C and Secundo, F and James, G and Villa, F and Cappitelli, F}, title = {α-Chymotrypsin Immobilized on a Low-Density Polyethylene Surface Successfully Weakens Escherichia coli Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {19}, number = {12}, pages = {}, pmid = {30545074}, issn = {1422-0067}, support = {2011-0277//Fondazione Cariplo/ ; }, mesh = {Biofilms/drug effects/*growth & development ; Biomass ; Chymotrypsin/*pharmacology ; Enzymes, Immobilized/*pharmacology ; Escherichia coli/drug effects/*physiology ; Microbial Viability/drug effects ; Polyethylene/*chemistry ; Surface Properties ; }, abstract = {The protease α-chymotrypsin (α-CT) was covalently immobilized on a low-density polyethylene (LDPE) surface, providing a new non-leaching material (LDPE-α-CT) able to preserve surfaces from biofilm growth over a long working timescale. The immobilized enzyme showed a transesterification activity of 1.24 nmol/h, confirming that the immobilization protocol did not negatively affect α-CT activity. Plate count viability assays, as well as confocal laser scanner microscopy (CLSM) analysis, showed that LDPE-α-CT significantly impacts Escherichia coli biofilm formation by (i) reducing the number of adhered cells (-70.7 ± 5.0%); (ii) significantly affecting biofilm thickness (-81.8 ± 16.7%), roughness (-13.8 ± 2.8%), substratum coverage (-63.1 ± 1.8%), and surface to bio-volume ratio (+7.1 ± 0.2-fold); and (iii) decreasing the matrix polysaccharide bio-volume (80.2 ± 23.2%). Additionally, CLSM images showed a destabilized biofilm with many cells dispersing from it. Notably, biofilm stained for live and dead cells confirmed that the reduction in the biomass was achieved by a mechanism that did not affect bacterial viability, reducing the chances for the evolution of resistant strains.}, } @article {pmid30543717, year = {2018}, author = {Koo, H and Andes, DR and Krysan, DJ}, title = {Candida-streptococcal interactions in biofilm-associated oral diseases.}, journal = {PLoS pathogens}, volume = {14}, number = {12}, pages = {e1007342}, pmid = {30543717}, issn = {1553-7374}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Candida albicans/*physiology ; Humans ; Microbiota ; Mouth Diseases/*microbiology ; Mouth Mucosa/*microbiology ; Streptococcus/*physiology ; }, } @article {pmid30543026, year = {2019}, author = {Giacaman, RA and Jobet-Vila, P and Muñoz-Sandoval, C}, title = {Anticaries activity of egg ovalbumin in an experimental caries biofilm model on enamel and dentin.}, journal = {Clinical oral investigations}, volume = {23}, number = {9}, pages = {3509-3516}, pmid = {30543026}, issn = {1436-3771}, support = {1140623//Fondo de Fomento al Desarrollo Científico y Tecnológico/ ; }, mesh = {Animals ; *Biofilms ; Cattle ; *Dental Caries ; Dental Enamel/drug effects ; *Dentin/drug effects ; *Ovalbumin/pharmacology ; Streptococcus mutans ; *Tooth Demineralization ; }, abstract = {OBJECTIVES: Limited evidence suggests a putative inhibitory effect of dietary proteins on demineralization during the carious process. The aim was to explore a potential anticaries activity of the egg protein ovalbumin on a relevant in vitro approach.

MATERIALS AND METHODS: Biofilms of Streptococcus mutans UA159 were formed on saliva-coated enamel and dentin bovine slabs. Biofilms were challenged with 10% sucrose followed by either a 200 μg/mL solution of ovalbumin or 1:10, 1:100, and 1:1000 (v/v) serial dilutions of that ovalbumin solution, for the entire length of the experiment. Biofilms exposed to 10% sucrose followed only by 0.9% NaCl served as caries-positive control. Once completed the experimental phase, biofilms were analyzed for biomass, viable bacteria, and polysaccharide formation. Final surface hardness (SH) was obtained to calculate %SH loss (demineralization). Two independent experiments were conducted, in triplicate. Data were analyzed by ANOVA and a post hoc test at the 95% confidence level.

RESULTS: A reduction (p < 0.05) in biomass and extracellular polysaccharide formation, but not in the number of viable cells, was observed for both dental substrates. All ovalbumin concentrations tested showed lower demineralization than the positive control (p < 0.05), in a dose-dependent manner. The highest concentration showed a reduction in the %SH loss of about 30% for both enamel and dentin.

CONCLUSION: Egg ovalbumin presented to sucrose-challenged biofilms of Streptococcus mutans seems to reduce cariogenicity of a biofilm-caries model.

CLINICAL RELEVANCE: Ovalbumin may counteract the cariogenic effect of sugars. If these findings are clinically confirmed, novel preventive approaches for caries are warranted.}, } @article {pmid30542331, year = {2018}, author = {Melloul, E and Roisin, L and Durieux, MF and Woerther, PL and Jenot, D and Risco, V and Guillot, J and Dannaoui, E and Decousser, JW and Botterel, F}, title = {Interactions of Aspergillus fumigatus and Stenotrophomonas maltophilia in an in vitro Mixed Biofilm Model: Does the Strain Matter?.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2850}, pmid = {30542331}, issn = {1664-302X}, abstract = {Introduction: Aspergillus fumigatus (Af) and Stenotrophomonas maltophilia (Sm) are pathogenic microorganisms, which coexist in the respiratory tract of cystic fibrosis (CF) patients. We recently developed an in vitro model of mixed biofilm associating Af ATCC 13073-GFP (Af13073) and Sm ATCC 13637 (Sm13637) and described an antibiosis effect. The present study aim was to assess the antibiosis of Sm on Af using different strains and to analyze the potential synergistic virulence of these strains in an in vivo Galleria mellonella model. Methods: The effect of Sm13637 was evaluated on eight Af strains and the effect of nine Sm strains was evaluated on Af13073. The strains originated from clinical cases (human and animal) and from environment. Fungal and bacterial inocula were simultaneously inoculated to initiate mixed biofilm formation. Fungal growth inhibition was analyzed by qPCR and CLSM and the fungal cell wall modifications by TEM analysis. The virulence of different Sm strains was assessed in association with Af in G. mellonella larvae. Results: All strains of Af and Sm were able to produce single and mixed biofilms. The antibiosis effect of Sm13637 was similar whatever the Af strain tested. On the other hand, the antibiosis effect of Sm strains was bacterial-fitness and strain dependent. One strain (1/9) originated from animal clinical case was never able to induce an antibiosis, even with high bacterial concentration. In the G. mellonella model, co-inoculation with Sm13637 and Af13073 showed synergism since the mortality was 50%, i.e., more than the summed virulence of both. Conclusion: Human clinical strains of Sm yielded in higher antibiosis effect on Af and in a thinner mixed biofilm, probably due to an adaptive effect of these strains. Further research covering Af increased wall thickness in the presence of Sm strains, and its correlation with modified antifungal susceptibility is encouraged in patients with chronic respiratory infections by these 2 microorganisms.}, } @article {pmid30525159, year = {2018}, author = {Sims, KR and Liu, Y and Hwang, G and Jung, HI and Koo, H and Benoit, DSW}, title = {Enhanced design and formulation of nanoparticles for anti-biofilm drug delivery.}, journal = {Nanoscale}, volume = {11}, number = {1}, pages = {219-236}, pmid = {30525159}, issn = {2040-3372}, support = {F31 DE026944/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry ; *Biofilms ; Biomass ; Cations ; Cell Membrane/metabolism ; Drug Carriers ; *Drug Delivery Systems ; Drug Design ; Durapatite/chemistry ; Farnesol/*chemistry ; Glucans/chemistry ; Hydrogen-Ion Concentration ; Micelles ; Microscopy, Confocal ; Nanoparticles/*chemistry ; Polymers/chemistry ; Pyrimidines/chemistry ; Quaternary Ammonium Compounds/chemistry ; Streptococcus mutans/metabolism ; }, abstract = {Biofilms are surface-bound, structured microbial communities underpinning persistent bacterial infections. Biofilms often create acidic pH microenvironments, providing opportunities to leverage responsive drug delivery systems to improve antibacterial efficacy. Here, the antibacterial efficacy of novel formulations containing pH-responsive polymer nanoparticle carriers (NPCs) and farnesol, a hydrophobic antibacterial drug, were investigated. Multiple farnesol-loaded NPCs, which varied in overall molecular weight and corona-to-core molecular weight ratios (CCRs), were tested using standard and saturated drug loading conditions. NPCs loaded at saturated conditions exhibited ∼300% greater drug loading capacity over standard conditions. Furthermore, saturated loading conditions sustained zero-ordered drug release over 48 hours, which was 3-fold longer than using standard farnesol loading. Anti-biofilm activity of saturated NPC loading was markedly amplified using Streptococcus mutans as a biofilm-forming model organism. Specifically, reductions of ∼2-4 log colony forming unit (CFU) were obtained using microplate and saliva-coated hydroxyapatite biofilm assays. Mechanistically, the new formulation reduced total biomass by disrupting insoluble glucan formation and increased NPC-cell membrane localization. Finally, thonzonium bromide, a highly potent, FDA-approved antibacterial drug with similar alkyl chain structure to farnesol, was also loaded into NPCs and used to treat S. mutans biofilms. Similar to farnesol-loaded NPCs, thonzonium bromide-loaded NPCs increased drug loading capacity ≥2.5-fold, demonstrated nearly zero-order release kinetics over 96 hours, and reduced biofilm cell viability by ∼6 log CFU. This work provides foundational insights that may lead to clinical translation of novel topical biofilm-targeting therapies, such as those for oral diseases.}, } @article {pmid30523630, year = {2019}, author = {Alabdullatif, M and Ramirez-Arcos, S}, title = {Biofilm-associated accumulation-associated protein (Aap): A contributing factor to the predominant growth of Staphylococcus epidermidis in platelet concentrates.}, journal = {Vox sanguinis}, volume = {114}, number = {1}, pages = {28-37}, doi = {10.1111/vox.12729}, pmid = {30523630}, issn = {1423-0410}, support = {//Canadian Blood Services, Health Canada/ ; //Al-Imam Muhammad Ibn Saud University/ ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Blood Safety/standards ; Humans ; Platelet-Rich Plasma/*microbiology ; Staphylococcus epidermidis/metabolism/*physiology ; }, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus epidermidis is a predominant contaminant of platelet concentrates (PCs), outcompeting other skin flora bacteria such as Staphylococcus capitis. The accumulation-associated protein (Aap), encoded by the aap gene, is involved in formation of bacterial aggregates (biofilms) in S. epidermidis and is absent in S. capitis. In this study, the role of S. epidermidis aap in enhancing biofilm formation and conferring an advantageous growth in PCs was investigated.

MATERIALS AND METHODS: Biofilm formation assays of S. epidermidis 1457, S. epidermidis 1457∆aap, S. capitis 517 and S. capitis 517 carrying S. epidermidis aap (S. capitis 517/pRBaap) were performed in glucose-supplemented trypticase soy broth (TSBg) and PCs. Additionally, competition assays with paired cultures (1:1 ratio) of S. epidermidis and S. capitis strains were seeded in PCs, followed by determination of viable counts of each organism at the end of PC storage.

RESULTS: Staphylococcus epidermidis aap had no effect on biofilm formation in TSBg. By contrast in PCs, S. epidermidis 1457 showed higher biofilm formation than S. epidermidis 1457∆aap (P < 0·05). Biofilm formation was also enhanced in S. capitis 517/pRBaap compared to S. capitis 517 (P = 0·054). Competition assays showed that S. epidermidis 1457 outcompeted S. capitis 517, and importantly, S. capitis 517/pRBaap outcompeted S. capitis 517 and S. epidermidis 1457∆aap.

CONCLUSION: This study demonstrated that S. epidermidis aap plays a role in biofilm formation in PCs conferring an advantageous proliferation to skin flora bacteria in this milieu. The molecular mechanisms of action of Aap merit further investigation.}, } @article {pmid30523448, year = {2019}, author = {Guo, CL and Wang, W and Duan, DR and Zhao, CY and Guo, FQ}, title = {Enhanced CO2 biofixation and protein production by microalgae biofilm attached on modified surface of nickel foam.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {4}, pages = {521-528}, doi = {10.1007/s00449-018-2055-4}, pmid = {30523448}, issn = {1615-7605}, mesh = {Biofilms/*growth & development ; Carbon Dioxide/*metabolism ; Membrane Proteins ; Microalgae/*physiology ; Nickel/*chemistry ; Photobioreactors ; Plant Proteins/*biosynthesis ; Scenedesmus/*physiology ; }, abstract = {In this work, a photobioreactor with microalgae biofilm was proposed to enhance CO2 biofixation and protein production using nickel foam with the modified surface as the carrier for immobilizing microalgae cells. The results demonstrated that, compared with microalgae suspension, microalgae biofilm lowered mass transfer resistance and promoted mass transfer efficiency of CO2 from the bubbles into the immobilized microalgae cells, enhancing CO2 biofixation and protein production. Moreover, parametric studies on the performance of the photobioreactor with microalgae biofilm were also conducted. The results showed that the photobioreactor with microalgae biofilm yielded a good performance with the CO2 biofixation rate of 4465.6 µmol m[-3] s[-1], the protein concentration of effluent liquid of 0.892 g L[-1], and the protein synthesis rate of 43.11 g m[-3] h[-1]. This work will be conducive to the optimization design of microalgae culture system for improving the performance of the photobioreactor.}, } @article {pmid30522530, year = {2018}, author = {Edlund, A and Yang, Y and Yooseph, S and He, X and Shi, W and McLean, JS}, title = {Uncovering complex microbiome activities via metatranscriptomics during 24 hours of oral biofilm assembly and maturation.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {217}, pmid = {30522530}, issn = {2049-2618}, support = {R01 DE026186/DE/NIDCR NIH HHS/United States ; R01 DE020102/DE/NIDCR NIH HHS/United States ; R01 DE023810/DE/NIDCR NIH HHS/United States ; R01 GM095373/GM/NIGMS NIH HHS/United States ; K99 DE024543/DE/NIDCR NIH HHS/United States ; R00 DE024543/DE/NIDCR NIH HHS/United States ; }, mesh = {Adult ; Bacteria/*classification/genetics/growth & development ; Bacterial Proteins/genetics ; Biofilms ; DNA, Bacterial/genetics ; DNA, Ribosomal/genetics ; Dental Plaque/*microbiology ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; Humans ; Hydrogen-Ion Concentration ; Metabolic Networks and Pathways ; Metagenomics/*methods ; Mouth/*microbiology ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA/methods ; }, abstract = {BACKGROUND: Dental plaque is composed of hundreds of bacterial taxonomic units and represents one of the most diverse and stable microbial ecosystems associated with the human body. Taxonomic composition and functional capacity of mature plaque is gradually shaped during several stages of community assembly via processes such as co-aggregation, competition for space and resources, and by bacterially produced reactive agents. Knowledge on the dynamics of assembly within complex communities is very limited and derives mainly from studies composed of a limited number of bacterial species. To fill current knowledge gaps, we applied parallel metagenomic and metatranscriptomic analyses during assembly and maturation of an in vitro oral biofilm. This model system has previously demonstrated remarkable reproducibility in taxonomic composition across replicate samples during maturation.

RESULTS: Time course analysis of the biofilm maturation was performed by parallel sampling every 2-3 h for 24 h for both DNA and RNA. Metagenomic analyses revealed that community taxonomy changed most dramatically between three and six hours of growth when pH dropped from 6.5 to 5.5. By applying comparative metatranscriptome analysis we could identify major shifts in overall community activities between six and nine hours of growth when pH dropped below 5.5, as 29,015 genes were significantly up- or down- expressed. Several of the differentially expressed genes showed unique activities for individual bacterial genomes and were associated with pyruvate and lactate metabolism, two-component signaling pathways, production of antibacterial molecules, iron sequestration, pH neutralization, protein hydrolysis, and surface attachment. Our analysis also revealed several mechanisms responsible for the niche expansion of the cariogenic pathogen Lactobacillus fermentum.

CONCLUSION: It is highly regarded that acidic conditions in dental plaque cause a net loss of enamel from teeth. Here, as pH drops below 5.5 pH to 4.7, we observe blooms of cariogenic lactobacilli, and a transition point of many bacterial gene expression activities within the community. To our knowledge, this represents the first study of the assembly and maturation of a complex oral bacterial biofilm community that addresses gene level functional responses over time.}, } @article {pmid30540782, year = {2018}, author = {Hickl, J and Argyropoulou, A and Sakavitsi, ME and Halabalaki, M and Al-Ahmad, A and Hellwig, E and Aligiannis, N and Skaltsounis, AL and Wittmer, A and Vach, K and Karygianni, L}, title = {Mediterranean herb extracts inhibit microbial growth of representative oral microorganisms and biofilm formation of Streptococcus mutans.}, journal = {PloS one}, volume = {13}, number = {12}, pages = {e0207574}, pmid = {30540782}, issn = {1932-6203}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Chromatography, High Pressure Liquid ; Cistus/chemistry/metabolism ; Mass Spectrometry ; Mediterranean Region ; Microbial Sensitivity Tests ; Phytochemicals/analysis/chemistry ; Plant Components, Aerial/chemistry/metabolism ; Plant Extracts/chemistry/*pharmacology ; Plants, Medicinal/*chemistry/metabolism ; Rosmarinus/chemistry/metabolism ; Streptococcus mutans/physiology ; }, abstract = {In light of the growing antibiotic resistance, the usage of plant-derived antimicrobial agents could serve as an effective alternative treatment against oral infections. The aim of this study was to investigate the antimicrobial and antibiofilm activity of Mediterranean herb extracts against representative oral microorganisms. The extraction procedures and the analysis of the obtained extracts were performed under established experimental conditions. The minimum inhibitory (MIC) and bactericidal (MBC) concentrations of the methanol extracts of Cistus creticus ssp. creticus, Cistus monspeliensis, Origanum vulgare, Rosmarinus officinalis, Salvia sclarea and Thymus longicaulis against eight typical oral bacteria and the fungus Candida albicans were determined. The antibiofilm activity against Streptococcus mutans was also quantified using the microtiter plate test. Overall, all tested extracts inhibited effectively the screened obligate anaerobic microorganisms and in concentrations ≥0.3 mg ml-1 had moderate to high antibiofilm activity comparable to that of chlorhexidine (CHX) against S. mutans. In particular, R. officinalis (MIC: 0.08-5.00 mg ml-1) and S. sclarea (MIC: 0.08-2.50 mg ml-1) showed the highest antibacterial activity, while Cistus spp., R. officinalis and S. sclarea significantly inhibited S. mutans biofilm formation at 0.60, 1.25 and 2.50 mg ml-1, respectively. Porphyromonas gingivalis and Parvimonas micra were high susceptible to O. vulgare (MIC = 0.30 mg ml-1), whereas T. longicaulis eradicated all oral bacteria (MBC: 0.15-2.50 mg ml-1). Nevertheless, C. albicans showed no sensitivity to the tested extracts. In conclusion, the tested plant extracts could serve as alternative natural antibacterial and antibiofilm components against oral infections.}, } @article {pmid30540247, year = {2019}, author = {Di Bonaventura, G and Pompilio, A and Monaco, M and Pimentel de Araujo, F and Baldassarri, L and Pantosti, A and Gherardi, G}, title = {Adhesion and biofilm formation by Staphylococcus aureus clinical isolates under conditions relevant to the host: relationship with macrolide resistance and clonal lineages.}, journal = {Journal of medical microbiology}, volume = {68}, number = {2}, pages = {148-160}, doi = {10.1099/jmm.0.000893}, pmid = {30540247}, issn = {1473-5644}, mesh = {A549 Cells ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects/genetics/*physiology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Clindamycin/pharmacology ; Drug Resistance, Bacterial/genetics ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin/pharmacology ; Female ; Genotype ; Humans ; Ketolides/pharmacology ; Macrolides/*pharmacology ; Male ; Methicillin-Resistant Staphylococcus aureus/classification/drug effects/genetics/physiology ; Middle Aged ; Multilocus Sequence Typing ; Penicillin-Binding Proteins/genetics ; Phenotype ; Staphylococcal Infections/epidemiology/*microbiology ; Staphylococcus aureus/classification/*drug effects/genetics/*physiology ; Young Adult ; }, abstract = {PURPOSE: Staphylococcus aureus isolates, collected from various clinical samples, were analysed to evaluate the contribution of the genetic background of both erythromycin-resistant (ERSA) and -susceptible (ESSA) S. aureus strains to biofilm formation.

METHODS: A total of 66 ESSA and 43 ERSA clinical isolates were studied for adhesiveness and biofilm formation under different atmospheres. All isolates were evaluated for phenotypic and genotypic macrolide resistance, and for clonal relatedness by pulsed-field gel electrophoresis (PFGE), and by spa typing on representative isolates.

RESULTS: A high genetic heterogeneity was encountered, although 10 major PFGE types accounted for 86 % with a few small spatially and temporally related clusters. Overall, biofilm formation under anoxia was significantly lower than under oxic and micro-aerophilic atmospheres. Biofilm formation by ESSA was significantly higher compared to ERSA under oxic and micro-aerophilic conditions. Adhesiveness to plastic was significantly higher among respiratory tract infection isolates under micro-aerophilic conditions, while surgical site infection isolates formed significantly higher biomass of biofilm under oxic and micro-aerophilic atmospheres compared to anoxia. Pulsotype 2 and 4 strains formed significantly higher biofilm biomass than pulsotype 1, with strains belonging to CC8 forming significantly more compared to those belonging to CC5, under both oxic and micro-aerophilic atmospheres.

CONCLUSIONS: S. aureus biofilm formation appears to be more efficient in ESSA than ERSA, associated with specific S. aureus lineages, mainly CC8 and CC15, and affected by atmosphere. Further studies investigating the relationship between antibiotic resistance and biofilm formation could prove useful in the development of new strategies for the management of S. aureus infections.}, } @article {pmid30539145, year = {2018}, author = {Mukherjee, M and Hu, Y and Tan, CH and Rice, SA and Cao, B}, title = {Engineering a light-responsive, quorum quenching biofilm to mitigate biofouling on water purification membranes.}, journal = {Science advances}, volume = {4}, number = {12}, pages = {eaau1459}, pmid = {30539145}, issn = {2375-2548}, mesh = {Bacteria/genetics/growth & development ; Bioengineering ; Biofilms/*growth & development/*radiation effects ; *Biofouling ; Escherichia coli/physiology/radiation effects ; Genetic Engineering ; *Light ; *Membranes, Artificial ; Plasmids/genetics ; *Quorum Sensing ; *Water Purification ; }, abstract = {Quorum quenching (QQ) has been reported to be a promising approach for membrane biofouling control. Entrapment of QQ bacteria in porous matrices is required to retain them in continuously operated membrane processes and to prevent uncontrollable biofilm formation by the QQ bacteria on membrane surfaces. It would be more desirable if the formation and dispersal of biofilms by QQ bacteria could be controlled so that the QQ bacterial cells are self-immobilized, but the QQ biofilm itself still does not compromise membrane performance. In this study, we engineered a QQ bacterial biofilm whose growth and dispersal can be modulated by light through a dichromatic, optogenetic c-di-GMP gene circuit in which the bacterial cells sense near-infrared (NIR) light and blue light to adjust its biofilm formation by regulating the c-di-GMP level. We also demonstrated the potential application of the engineered light-responsive QQ biofilm in mitigating biofouling of water purification forward osmosis membranes. The c-di-GMP-targeted optogenetic approach for controllable biofilm development we have demonstrated here should prove widely applicable for designing other controllable biofilm-enabled applications such as biofilm-based biocatalysis.}, } @article {pmid30538678, year = {2018}, author = {Manandhar, S and Singh, A and Varma, A and Pandey, S and Shrivastava, N}, title = {Biofilm Producing Clinical Staphylococcus aureus Isolates Augmented Prevalence of Antibiotic Resistant Cases in Tertiary Care Hospitals of Nepal.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2749}, pmid = {30538678}, issn = {1664-302X}, abstract = {Staphylococcus aureus, a notorious human pathogen, is a major cause of the community as well as healthcare associated infections. It can cause a diversity of recalcitrant infections mainly due to the acquisition of resistance to multiple drugs, its diverse range of virulence factors, and the ability to produce biofilm in indwelling medical devices. Such biofilm associated chronic infections often lead to increase in morbidity and mortality posing a high socio-economic burden, especially in developing countries. Since biofilm formation and antibiotic resistance function dependent on each other, detection of biofilm expression in clinical isolates would be advantageous in treatment decision. In this premise, we attempt to investigate the biofilm formation and its association with antibiotic resistance in clinical isolates from the patients visiting tertiary health care hospitals in Nepal. Bacterial cells isolated from clinical samples identified as S. aureus were examined for in-vitro biofilm production using both phenotypic and genotypic assays. The S. aureus isolates were also examined for susceptibility patterns of clinically relevant antibiotics as well as inducible clindamycin resistance using standard microbiological techniques and D-test, respectively. Among 161 S. aureus isolates, 131 (81.4%) were methicillin resistant S. aureus (MRSA) and 30 (18.6%) were methicillin sensitive S. aureus (MSSA) strains. Although a majority of MRSA strains (69.6%) showed inducible clindamycin resistance, almost all isolates (97% and 94%) were sensitive toward chloramphenicol and tetracycline, respectively. Detection of in vitro production of biofilm revealed the association of biofilm with methicillin as well as inducible clindamycin resistance among the clinical S. aureus isolates.}, } @article {pmid30538510, year = {2018}, author = {Tulasidas, S and Rao, P and Bhat, S and Manipura, R}, title = {A study on biofilm production and antifungal drug resistance among Candida species from vulvovaginal and bloodstream infections.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {2443-2448}, pmid = {30538510}, issn = {1178-6973}, abstract = {INTRODUCTION: Candida species, one among the opportunistic fungi, has become a common pathogen causing vaginal thrush and nosocomial bloodstream infections (BSIs). This study aims to evaluate the prevalence and antifungal susceptibility of various Candida species and slime production by Candida species in BSIs and vulvovaginal candidiasis (VVC).

MATERIALS AND METHODS: A total of 176 samples were collected for a period of 1 year. Anti-fungal susceptibility testing and biofilm production testing were performed by the Kirby-Bauer method and crystal violet assay, respectively.

RESULTS: Out of 176 samples, 74 (42%) were from BSIs and 102 (58%) were from VVC. The biofilm production was comparatively high in blood isolates, 55 (74%), than cervical isolates, 45 (44%). Increase in the trends of non-albicans Candida (NAC) species was seen in our setup. Good susceptibility rates were seen among Candida species, 82.38% to voriconazole and an increasing resistance pattern of 26.13% to fluconazole.

CONCLUSION: Speciation of Candida becomes important as the prevalence of NAC is increasing. Antifungal susceptibility testing by the disk diffusion method is cost effective and should be adopted in routine testing as there is an increasing azole resistance, especially in invasive NAC infections. In this study, there was no correlation of antifungal drugs with the biofilm production.}, } @article {pmid30538189, year = {2018}, author = {Mokrzan, EM and Novotny, LA and Brockman, KL and Bakaletz, LO}, title = {Antibodies against the Majority Subunit (PilA) of the Type IV Pilus of Nontypeable Haemophilus influenzae Disperse Moraxella catarrhalis from a Dual-Species Biofilm.}, journal = {mBio}, volume = {9}, number = {6}, pages = {}, pmid = {30538189}, issn = {2150-7511}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; }, mesh = {Antibodies, Bacterial/*immunology ; Biofilms/*drug effects/*growth & development ; Fimbriae Proteins/*immunology ; Fimbriae, Bacterial/*immunology ; Haemophilus influenzae/immunology ; Humans ; Moraxella catarrhalis/*drug effects/*growth & development ; }, abstract = {Otitis media (OM) is often polymicrobial, with nontypeable Haemophilus influenzae (NTHI) and Moraxella catarrhalis (Mcat) frequently cocultured from clinical specimens. Bacterial biofilms in the middle ear contribute to the chronicity and recurrence of OM; therefore, strategies to disrupt biofilms are needed. We have focused our vaccine development efforts on the majority subunit of NTHI type IV pili, PilA. Antibodies against a recombinant, soluble form of PilA (rsPilA) both disrupt and prevent the formation of NTHI biofilms in vitro. Moreover, immunization with rsPilA prevents and resolves NTHI-induced experimental OM. Here, we show that antibodies against rsPilA also prevent and disrupt polymicrobial biofilms. Dual-species biofilms formed by NTHI and Mcat at temperatures that mimic the human nasopharynx (34°C) or middle ear (37°C) were exposed to antiserum against either rsPilA or the OMP P5 adhesin of NTHI. NTHI+Mcat biofilm formation was significantly inhibited by antiserum directed against both adhesin proteins at either temperature. However, only anti-rsPilA disrupted NTHI+Mcat preestablished biofilms at either temperature and actively dispersed both NTHI and Mcat via interspecies quorum signaling. Newly released NTHI and Mcat were significantly more susceptible to killing by antibiotics. Taken together, these results revealed new opportunities for treatment of biofilm-associated diseases via a strategy that combines vaccine-induced antibody-mediated biofilm dispersal with traditional antibiotics, at a significantly reduced dosage to exploit the newly released, antibiotic-sensitive phenotype. Combined, our data strongly support the utility of rsPilA both as a preventative and as a therapeutic vaccine antigen for polymicrobial OM due to NTHI and Mcat.IMPORTANCE Middle ear infections (or otitis media [OM]) are highly prevalent among children worldwide and present a tremendous socioeconomic challenge for health care systems. More importantly, this disease diminishes the quality of life of young children. OM is often chronic and recurrent, due to the presence of highly antibiotic-resistant communities of bacteria (called biofilms) that persist within the middle ear space. To combat these recalcitrant infections, new and powerful biofilm-directed approaches are needed. Here, we describe the ability to disrupt a biofilm formed by the two most common bacteria that cause chronic and recurrent OM in children, via an approach that combines the power of vaccines with that of traditional antibiotics. An outcome of this strategy is that antibiotics can more easily kill the bacteria that our vaccine-induced antibodies have released from the biofilm. We believe that this approach holds great promise for both the prevention and treatment of OM.}, } @article {pmid30537651, year = {2019}, author = {Zhang, J and Li, W and Chen, J and Wang, F and Qi, W and Li, Y}, title = {Impact of disinfectant on bacterial antibiotic resistance transfer between biofilm and tap water in a simulated distribution network.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {246}, number = {}, pages = {131-140}, doi = {10.1016/j.envpol.2018.11.077}, pmid = {30537651}, issn = {1873-6424}, mesh = {Bacteria/classification/drug effects ; Biofilms/*drug effects/growth & development ; Disinfectants/*pharmacology ; Drinking Water/*microbiology ; Drug Resistance, Bacterial/*drug effects ; Humans ; Time Factors ; Water Purification ; *Water Supply ; }, abstract = {Bacterial antibiotic resistance (BAR) is profoundly important to human health, but the environmental reservoirs of resistance determinants are poorly understood. BAR of biofilm and tap water were analyzed by using a water distribution simulator where different doses of chlorine and chloramine were used in this study. The results revealed that the disinfectants (≥2 mg/L) suppressed antibiotic resistant bacteria (ARB) in tap water and biofilms, while disinfected water and biofilms had a high relative abundance of ARB. The difference of ARB concentration and ARB percentage between the samples obtained from a disinfected pipeline and a non-disinfected pipeline became smaller over time. Because the water supply system is a unidirectional process, it is unclear how planktonic bacteria in water transfer BAR over time, although biofilm is suspected to play a role in this process. Compared with the biofilm samples without disinfectant, the disinfected biofilm had lower ICC and HPC/ICC percentage, lower AOC and AOC/TOC percentage, indicating that the disinfectant inhibited the bacteria growth in biofilm, and the disinfected biofilm had high proportion of non-culturable bacteria and low biodegradability, which affected BAR in biofilms. High throughput sequencing showed that in biofilms, the relative abundance of genera (uncultured_f_Rhodocyclaceae, Brevundimonas, and Brevibacillus in chlorinated systems, and Brevundimonas, Brevibacillus in chloraminated systems) with multiple antibiotic resistance and high abundance (up to 78.5%), were positively associated with disinfectant concentration and ARB percentage. The major prevalent genera in biofilms were also detected in tap water, suggesting that biofilm growth or biofilm detachment caused by external environmental factors will allow the movement of biofilm clusters with higher ARB concentration and percentage into bulk water, thereby increasing the antibiotic resistance of bacteria in tap water.}, } @article {pmid30537413, year = {2019}, author = {Conforte, VP and Malamud, F and Yaryura, PM and Toum Terrones, L and Torres, PS and De Pino, V and Chazarreta, CN and Gudesblat, GE and Castagnaro, AP and R Marano, M and Vojnov, AA}, title = {The histone-like protein HupB influences biofilm formation and virulence in Xanthomonas citri ssp. citri through the regulation of flagellar biosynthesis.}, journal = {Molecular plant pathology}, volume = {20}, number = {4}, pages = {589-598}, pmid = {30537413}, issn = {1364-3703}, mesh = {Biofilms/*growth & development ; Flagella/*metabolism ; Mutation ; Virulence/genetics/physiology ; Xanthomonas/genetics/*metabolism/*pathogenicity ; }, abstract = {Citrus canker is an important disease of citrus, whose causal agent is the bacterium Xanthomonas citri ssp. citri (Xcc). In previous studies, we found a group of Xcc mutants, generated by the insertion of the Tn5 transposon, which showed impaired ability to attach to an abiotic substrate. One of these mutants carries the Tn5 insertion in hupB, a gene encoding a bacterial histone-like protein, homologue to the β-subunit of the Heat-Unstable (HU) nucleoid protein of Escherichia coli. These types of protein are necessary to maintain the bacterial nucleoid organization and the global regulation of gene expression. Here, we characterized the influence of the mutation in hupB regarding Xcc biofilm formation and virulence. The mutant strain hupB was incapable of swimming in soft agar, whereas its complemented strain partially recovered this phenotype. Electron microscope imaging revealed that impaired motility of hupB was a consequence of the absence of the flagellum. Comparison of the expression of flagellar genes between the wild-type strain and hupB showed that the mutant exhibited decreased expression of fliC (encoding flagellin). The hupB mutant also displayed reduced virulence compared with the wild-type strain when they were used to infect Citrus lemon plants using different infection methods. Our results therefore show that the histone-like protein HupB plays an essential role in the pathogenesis of Xcc through the regulation of biofilm formation and biosynthesis of the flagellum.}, } @article {pmid30535568, year = {2019}, author = {Meyer-Kobbe, V and Doll, K and Stiesch, M and Schwestka-Polly, R and Demling, A}, title = {Comparison of intraoral biofilm reduction on silver-coated and silver ion-implanted stainless steel bracket material : Biofilm reduction on silver ion-implanted bracket material.}, journal = {Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie}, volume = {80}, number = {1}, pages = {32-43}, pmid = {30535568}, issn = {1615-6714}, mesh = {Adult ; *Biofilms/growth & development ; Female ; Humans ; Male ; Microscopy, Confocal ; Orthodontic Brackets/*microbiology ; *Silver ; *Stainless Steel ; Young Adult ; }, abstract = {PURPOSE: The objective of this in situ study was to quantify the intraoral biofilm reduction on bracket material as a result of different surface modifications using silver ions. In addition to galvanic silver coating and physical vapor deposition (PVD), the plasma immersion ion implantation and deposition (PIIID) procedure was investigated for the first time within an orthodontic application.

MATERIALS AND METHODS: An occlusal splint equipped with differently silver-modified test specimens based on stainless steel bracket material was prepared for a total of 12 periodontally healthy patients and was worn in the mouth for 48 h. The initially formed biofilm was fluorescently stained and a quantitative comparative analysis of biofilm volume, biofilm surface coverage and live/dead distribution of bacteria was performed by confocal laser scanning microscopy (CLSM).

RESULTS: Compared to untreated stainless steel bracket material, the antibacterial effect of the PIIID silver-modified surface was just as significant with regard to reducing the biofilm volume and the surface coverage as the galvanically applied silver layer and the PVD silver coating. Regarding the live/dead distribution, however, the PIIID modification was the only surface that showed a significant increase in the proportion of dead cells compared to untreated bracket material and the galvanic coating.

CONCLUSIONS: Orthodontic stainless steel with a silver-modified surface by PIIID procedure showed an effective reduction in the intraoral biofilm formation compared to untreated bracket material, in a similar manner to PVD and galvanic silver coatings applied to the surface. Additionally, the PIIID silver-modified surface has an increased bactericidal effect.}, } @article {pmid30534118, year = {2018}, author = {Muthamil, S and Balasubramaniam, B and Balamurugan, K and Pandian, SK}, title = {Synergistic Effect of Quinic Acid Derived From Syzygium cumini and Undecanoic Acid Against Candida spp. Biofilm and Virulence.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2835}, pmid = {30534118}, issn = {1664-302X}, abstract = {In recent decades, fungal infections have incredibly increased with Candida genus as the major cause of morbidity and mortality in hospitalized and immunocompromised patients. Most of the Candida species are proficient in biofilm formation on implanted medical devices as well as human tissues. Biofilm related Candida infections are very difficult to treat using common antifungal agents owing to their increased drug resistance. To address these issues, the present study investigated the antibiofilm and antivirulent properties of Syzygium cumini derived quinic acid in combination with known antifungal compound undecanoic acid. Initially, antibiofilm potential of S. cumini leaf extract was assessed and the active principles were identified through gas chromatography and mass spectrometry analysis. Among the compounds identified, quinic acid was one of the major compounds. The interaction between quinic acid and undecanoic acid was found to be synergistic in the Fractional inhibitory concentration index (≤0.5). Results of in vitro assays and gene expression analysis suggested that the synergistic combinations of quinic acid and undecanoic acid significantly inhibited virulence traits of Candida spp. such as the biofilm formation, yeast-to-hyphal transition, extracellular polymeric substances production, filamentation, secreted hydrolases production and ergosterol biosynthesis. In addition, result of in vivo studies using Caenorhabditis elegans demonstrated the non-toxic nature of QA-UDA combination and antivirulence effect against Candida spp. For the first time, synergistic antivirulence ability of quinic acid and undecanoic acid was explored against Candida spp. Thus, results obtained from the present study suggest that combination of phytochemicals might be used an alternate therapeutic strategy for the prevention and treatment of biofilm associated Candida infection.}, } @article {pmid30532745, year = {2018}, author = {Andreozzi, E and Gunther, NW and Reichenberger, ER and Rotundo, L and Cottrell, BJ and Nuñez, A and Uhlich, GA}, title = {Pch Genes Control Biofilm and Cell Adhesion in a Clinical Serotype O157:H7 Isolate.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2829}, pmid = {30532745}, issn = {1664-302X}, abstract = {In a previous study, induction of the Escherichia coli serotype O157:H7 SOS response decreased csgD expression in the clinical isolate PA20 at 30°C but strongly induced genes in the horizontally transferred-DNA regions (HTR), including many known virulence regulators. To determine the role of HTR regulators in the control of csgD and curli, specific regulators were plasmid-expressed in the wild-type and mutant strains of PA20 and its biofilm-forming derivative, 20R2R. At 30°C, plasmid over-expression of the O157:H7 group 3 perC homolog, pchE, strongly repressed PA20 csgD transcription (>7-fold) while the group 1 homologs, pchA and pchB, resulted in smaller reductions (<2.5-fold). However, SOS induction decreased rather than increased pchE expression (>6-fold) making group 1 pch, which are enhanced by the SOS response, the likely SOS-induced csgD repressors. Plasmid-based pchE over-expression also reduced 20R2R biofilm formation (>6-fold) and the curli-dependent, Congo red affinity of both PA20 and 20R2R. However, to properly appreciate the regulatory direction, expression patterns, and environmental consequences of these and other CsgD-controlled functions, a better understanding of natural pchE regulation will be required. The effects of HTR regulators on PA20 and 20R2R adhesion to HEp-2 cell at host temperature were also studied. Under conditions where prophage genes were not induced, curli, rather than espA, contributed to host cell adhesion in strain 20R2R. High levels of pchE expression in trans reduced curli-dependent cell adherence (>2-fold) to both 20R2R and the clinical isolate PA20, providing a host-adapting adhesion control mechanism. Expression of pchE was also repressed by induction of the SOS response at 37°C, providing a mechanism by which curli expression might complement EspA-dependent intimate adhesion initiated by the group1 pch homologs. This study has increased our understanding of the O157 pch genes at both host and environment temperatures, identifying pchE as a strong regulator of csgD and CsgD-dependent properties.}, } @article {pmid30530941, year = {2019}, author = {Jeffet, U and Sterer, N}, title = {Effect of mucoadhesive agent HEC on herbal extracts retention and VSC producing bacteria reduction in an experimental oral biofilm.}, journal = {Journal of breath research}, volume = {13}, number = {2}, pages = {026004}, doi = {10.1088/1752-7163/aaf6f7}, pmid = {30530941}, issn = {1752-7163}, mesh = {Adhesives/*pharmacology ; Animals ; Bacteria/drug effects/metabolism ; Biofilms/*drug effects ; Cellulose/*analogs & derivatives/pharmacology ; Humans ; Mouth/*microbiology ; Mucus/*chemistry ; Plant Extracts/*pharmacology ; Salivary Proteins and Peptides/metabolism ; Sulfides/*analysis ; Sus scrofa ; Volatilization ; }, abstract = {Mucoadhesive tablets containing herbal formulation have been previously shown to reduce oral malodour. The aim of the present in vitro study was to test the effect of the mucoadhesive agent hydroxyethylcellulose (HEC) added to a liquid phase herbal extract formulation on the mucoadhesive retention of the active ingredients and their effect against malodour production. Experimental oral biofilms were grown on mucin coated glass slides treated with liquid phase solutions of herbal extract with or without HEC as well as saline and 0.2% chlorhexidine as controls. Biofilms were quantified for volatile sulfide compounds (VSC) producing bacteria using CLSM and sampled for a salivary incubation assay to test for malodour production (odour judge), VSC production (Halimeter) and salivary protein degradation (SDS-PAGE). Results showed that the addition of HEC to the herbal extracts solution has significantly increased its mucin retained activity against malodour producing bacteria and their resulting malodour and VSC production and proteolytic activities. Taken together, results of the present study suggest that the addition of HEC to a liquid phase herbal extract solution may increase its bioavailability time and efficacy. However, due to the limitations of this in vitro study additional clinical investigations are needed.}, } @article {pmid30528685, year = {2019}, author = {Simon, G and Bérubé, C and Voyer, N and Grenier, D}, title = {Anti-biofilm and anti-adherence properties of novel cyclic dipeptides against oral pathogens.}, journal = {Bioorganic & medicinal chemistry}, volume = {27}, number = {12}, pages = {2323-2331}, doi = {10.1016/j.bmc.2018.11.042}, pmid = {30528685}, issn = {1464-3391}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Candida albicans/drug effects/physiology ; Dipeptides/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Peptides, Cyclic/chemical synthesis/chemistry/*pharmacology ; Streptococcus mutans/drug effects/physiology ; Structure-Activity Relationship ; }, abstract = {Microorganisms embedded in a biofilm are significantly more resistant to antimicrobial agents and the defences of the human immune system, than their planktonic counterpart. Consequently, compounds that can inhibit biofilm formation are of great interest for novel therapeutics. In this study, a screening approach was used to identify novel cyclic dipeptides that have anti-biofilm activity against oral pathogens. Five new active compounds were identified that prevent biofilm formation by the cariogenic bacterium Streptococcus mutans and the pathogenic fungus Candida albicans. These compounds also inhibit the adherence of microorganisms to a hydroxylapatite surface. Further investigations were conducted on these compounds to establish the structure-activity relationship, and it was deduced that the common cleft pattern is required for these molecules to act effectively against biofilms.}, } @article {pmid30528295, year = {2019}, author = {Dias, HB and Bernardi, MIB and Bauab, TM and Hernandes, AC and de Souza Rastelli, AN}, title = {Titanium dioxide and modified titanium dioxide by silver nanoparticles as an anti biofilm filler content for composite resins.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {2}, pages = {e36-e46}, doi = {10.1016/j.dental.2018.11.002}, pmid = {30528295}, issn = {1879-0097}, mesh = {Biofilms ; Composite Resins ; *Metal Nanoparticles ; *Nanoparticles ; Silver ; Streptococcus mutans ; Titanium ; }, abstract = {OBJECTIVE: The aim of this study was to evaluate the antibacterial activity of a composite resin modified by TiO2 and TiO2/Ag nanoparticles and their influence over different properties.

METHODS: TiO2 and TiO2/Ag NPs were synthesized by polymeric precursor and microwave-assisted hydrothermal methods and then, characterized by different techniques. Direct contact test was performed using Filtek™ Z350XT blended with 0.5; 1 and 2% (wt.) of NPs against Streptococcus mutans to determine the best concentration to the other tests. After that, the modified composite resin was tested against S. mutans 7-day biofilm (CFU/mL). Also, compressive and diametral tensile strength (n=40), degree of conversion (n=25) and surface roughness (n=50) was performed. The data were analyzed by ANOVA and Tukey's test for multiple comparison at 5% significance level.

RESULTS: The direct contact test demonstrates that by increasing the nanoparticle content, the bacterial growth is significantly reduceed (p<0.05). The inclusion of 2% of TiO2/Ag NPs significantly decreased (p<0.05) the biofilm accumulation of S. mutans on the composite resin surface compared to the control Group. The TiO2 NPs treated with an organosilane increased compressive strength of composite resin (p<0.05). Degree of conversion remained unchanged (p>0.05) and the surface roughness increased with the NPs (p<0.05), except for the TiO2 by polymeric precursor Group (p>0.05).

SIGNIFICANCE: The development of an antibacterial dental restorative material that hinder S. mutans biofilm without sacrificing the mechanical and physical properties is desirable in dental material science.}, } @article {pmid30527687, year = {2019}, author = {Pérez-Ibarreche, M and Mendoza, LM and Vignolo, G and Fadda, S}, title = {Corrigendum to "Proteomic and genetics insights on the response of the bacteriocinogenic Lactobacillus sakei CRL1862 during biofilm formation on stainless steel surface at 10 °C" [Int. J. Food Microbiol. 258 (2017), 18-27].}, journal = {International journal of food microbiology}, volume = {301}, number = {}, pages = {73}, doi = {10.1016/j.ijfoodmicro.2018.11.029}, pmid = {30527687}, issn = {1879-3460}, } @article {pmid30526060, year = {2019}, author = {Rodríguez-Melcón, C and Capita, R and Rodríguez-Jerez, JJ and Martínez-Suárez, JV and Alonso-Calleja, C}, title = {Effect of Low Doses of Disinfectants on the Biofilm-Forming Ability of Listeria monocytogenes.}, journal = {Foodborne pathogens and disease}, volume = {16}, number = {4}, pages = {262-268}, doi = {10.1089/fpd.2018.2472}, pmid = {30526060}, issn = {1556-7125}, mesh = {Benzalkonium Compounds/pharmacology ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Food Contamination/*prevention & control ; *Food Microbiology ; Humans ; Listeria monocytogenes/*drug effects/physiology ; Microbial Sensitivity Tests ; Sodium Hypochlorite/pharmacology ; }, abstract = {This study was intended to investigate the effect of contact with concentrations close to the minimum inhibitory concentration (MIC) (0.5, 1, and 1.5 MIC; MIC of planktonic cells was determined using a microdilution broth method) of sodium hypochlorite (SHY) or benzalkonium chloride (BZK) during the process of formation of biofilm (24 h), upon the architecture and viability of the biofilms formed by four L. monocytogenes isolates of molecular serotype 1/2a: S2-1 (BZK-susceptible strain; MICBZK = 3.0 ppm), S2-2 (BZK-resistant strain qacH positive; MICBZK = 13 ppm), CDL 69 (BZK-resistant strain bcrABC positive; MICBZK = 10 ppm), and S2[BAC] (BZK-resistant laboratory mutant of S2-1, with multidrug resistance phenotype; MICBZK = 9 ppm). Images were examined through confocal laser scanning microscopy after staining with SYTO 9 and Propidium Iodide. Biovolume values in the observation field (14,161 μm[2]) in the absence of biocides ranged from 103,928.3 ± 6,730.2 μm[3] (S2[BAC]) to 276,030.9 ± 42,291.9 μm[3] (S2-1). Exposure to SHY at 0.5 MIC reduced (p < 0.05) the biovolume of biofilms formed by S2-1 and S2[BAC] and did not modify (p > 0.05) the biovolume of biofilms by S2-2 and CDL 69. Exposure to sub-MICs of BZK decreased (p < 0.05; S2-1) or enhanced (p < 0.05; S2-2, CDL 69 and S2[BAC]) biofilm development. Exposure to biocides at 1 or 1.5 MIC inhibited biofilm formation. This study provides clear evidence that BZK at sub-MICs can enhance the biofilm-forming ability of BZK-resistant L. monocytogenes strains. Because biofilms contribute to the persistence of bacteria throughout the food chain and represent a major source of food contamination, our findings suggest the importance of avoiding sub-MICs of disinfectants in food-handling environments.}, } @article {pmid30525713, year = {2018}, author = {Yu, Y and Klauda, JB}, title = {Modeling Pseudomonas aeruginosa inner plasma membrane in planktonic and biofilm modes.}, journal = {The Journal of chemical physics}, volume = {149}, number = {21}, pages = {215102}, doi = {10.1063/1.5052629}, pmid = {30525713}, issn = {1089-7690}, mesh = {*Biofilms ; Cell Membrane/*metabolism ; Deuterium/metabolism ; Hydrogen Bonding ; Lipid Metabolism ; Membrane Lipids/chemistry ; Models, Biological ; Molecular Dynamics Simulation ; Plankton/growth & development/*metabolism ; Pseudomonas aeruginosa/growth & development/*metabolism ; }, abstract = {Pseudomonas aeruginosa changes its growth modes under different conditions. The bacteria in biofilm is more resistant to environmental stress compared to the planktonic mode of growth. The compositions of the inner plasma membrane for the two modes are noticeably different. Major lipid types are chosen from experiment to model the membrane in both modes of growth, and molecular dynamics simulation is used to study the properties of the membrane. The CHARMM36 lipid force field is used and tested against several experimental results. Our models include lipids containing cyclopropane in the middle of the sn-2 tail, namely, 1-palmitoyl-2-cis-11,12-methylene-stearic-acid-sn-glycero-3-phosphoethanolamine and 1-palmitoyl-2-cis-11,12-methylene-stearic-acid-sn-glycero-3-phosphoglycerol. The PE:PG ratio for the two model membranes is close, but the fraction of lipids composed of long-chain and cyclopropane-containing fatty acids changes significantly, causing differences between the two models. Compared to previous model membranes built for Escherichia coli, the inner membrane of P. aeruginosa has a longer averaged lipid tail length and a higher percentage of PG lipids, which are responsible for the changes in membrane properties like membrane thickness and stiffness. Most importantly, the comparison to experiments shows good agreements and encourages the model's use to study the behavior of proteins from P. aeruginosa associated with the membrane.}, } @article {pmid30525377, year = {2019}, author = {Shen, H and López-Guerra, EA and Zhu, R and Diba, T and Zheng, Q and Solares, SD and Zara, JM and Shuai, D and Shen, Y}, title = {Visible-Light-Responsive Photocatalyst of Graphitic Carbon Nitride for Pathogenic Biofilm Control.}, journal = {ACS applied materials & interfaces}, volume = {11}, number = {1}, pages = {373-384}, doi = {10.1021/acsami.8b18543}, pmid = {30525377}, issn = {1944-8252}, mesh = {Anti-Infective Agents/*chemistry ; Biofilms/*growth & development/radiation effects ; Graphite/*chemistry ; *Light ; Nitriles/*chemistry ; Staphylococcus epidermidis/*physiology ; }, abstract = {Pathogenic biofilms raise significant health and economic concerns, because these bacteria are persistent and can lead to long-term infections in vivo and surface contamination in healthcare and industrial facilities or devices. Compared with conventional antimicrobial strategies, photocatalysis holds promise for biofilm control because of its broad-spectrum effectiveness under ambient conditions, low cost, easy operation, and reduced maintenance. In this study, we investigated the performance and mechanism of Staphylococcus epidermidis biofilm control and eradication on the surface of an innovative photocatalyst, graphitic carbon nitride (g-C3N4), under visible-light irradiation, which overcame the need for ultraviolet light for many current photocatalysts (e.g., titanium dioxide (TiO2)). Optical coherence tomography and confocal laser scanning microscopy (CLSM) suggested that g-C3N4 coupons inhibited biofilm development and eradicated mature biofilms under the irradiation of white light-emitting diodes. Biofilm inactivation was observed occurring from the surface toward the center of the biofilms, suggesting that the diffusion of reactive species into the biofilms played a key role. By taking advantage of scanning electron microscopy, CLSM, and atomic force microscopy for biofilm morphology, composition, and mechanical property characterization, we demonstrated that photocatalysis destroyed the integrated and cohesive structure of biofilms and facilitated biofilm eradication by removing the extracellular polymeric substances. Moreover, reactive oxygen species generated during g-C3N4 photocatalysis were quantified via reactions with radical probes and [1]O2 was believed to be responsible for biofilm control and removal. Our work highlights the promise of using g-C3N4 for a broad range of antimicrobial applications, especially for the eradication of persistent biofilms under visible-light irradiation, including photodynamic therapy, environmental remediation, food-industry applications, and self-cleaning surface development.}, } @article {pmid30521892, year = {2019}, author = {Mnif, S and Jardak, M and Graiet, I and Abid, S and Driss, D and Kharrat, N}, title = {The novel cationic cell-penetrating peptide PEP-NJSM is highly active against Staphylococcus epidermidis biofilm.}, journal = {International journal of biological macromolecules}, volume = {125}, number = {}, pages = {262-269}, doi = {10.1016/j.ijbiomac.2018.12.008}, pmid = {30521892}, issn = {1879-0003}, mesh = {Amino Acid Sequence ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Cell-Penetrating Peptides/chemistry/*pharmacology ; Hemolysis ; Humans ; Microbial Sensitivity Tests ; Molecular Conformation ; Staphylococcus epidermidis/*drug effects ; }, abstract = {A cationic cell-penetrating peptide PEP-NJSM was identified in human virus proteomes by a screening of charge clusters in protein sequences generating Cell-Penetrating Peptides (CPP). PEP-NJSM was selectively active against Gram-positive Staphylococcus epidermidis as antibacterial agent with MIC value of 128 μM compared to the Gram-negative Pseudomonas aeruginosa strain with MIC value exceeded 512 μM. The selected peptide exhibited an important anti-biofilm activity even at sub-MIC levels. PEP-NJSM could prevent biofilm formation and increase the mortality of cells inside mature S. epidermidis biofilm. The results demonstrated that PEP-NJSM presented an important anti-adherent activity. It showed a S. epidermidis inhibition of biofilm formation >84% at a concentration of 256 μM (2 X MIC) and remained active even at a concentration of 4 μM with 32% of inhibition. The eradication of the established biofilm was observed at a concentration of 256 μM with 55.7% of biofilm eradication. The peptide was active against mature biofilm even at low concentration of 0.5 μM with approximately 22.9% of eradication. PEP-NJSM exhibited low hemolytic activity and cytotoxicity against mammalian cells. Our results demonstrate that PEP-NJSM could have a potential role in the treatment of diseases related to Staphylococcus epidermidis infection.}, } @article {pmid30519367, year = {2017}, author = {Nussbaumer, MG and Nguyen, PQ and Tay, PKR and Naydich, A and Hysi, E and Botyanszki, Z and Joshi, NS}, title = {Bootstrapped Biocatalysis: Biofilm-Derived Materials as Reversibly Functionalizable Multienzyme Surfaces.}, journal = {ChemCatChem}, volume = {9}, number = {23}, pages = {4328-4333}, pmid = {30519367}, issn = {1867-3880}, support = {R01 DK110770/DK/NIDDK NIH HHS/United States ; }, abstract = {Cell-free biocatalysis systems offer many benefits for chemical manufacturing, but their widespread applicability is hindered by high costs associated with enzyme purification, modification, and immobilization on solid substrates, in addition to the cost of the material substrates themselves. Herein, we report a "bootstrapped" biocatalysis substrate material that is produced directly in bacterial culture and is derived from biofilm matrix proteins, which self-assemble into a nanofibrous mesh. We demonstrate that this material can simultaneously purify and immobilize multiple enzymes site specifically and directly from crude cell lysates by using a panel of genetically programmed, mutually orthogonal conjugation domains. We further demonstrate the utility of the technique in a bienzymatic stereoselective reduction coupled with a cofactor recycling scheme. The domains allow for several cycles of selective removal and replacement of enzymes under mild conditions to regenerate the catalyst system.}, } @article {pmid30519120, year = {2018}, author = {Nuryastuti, T and Umaroh, N and Asdie, RH and Sari, IP and Musthafa, A}, title = {Pan-drug-resistant and biofilm-producing strain of Burkholderia pseudomallei: first report of melioidosis from a diabetic patient in Yogyakarta, Indonesia.}, journal = {International medical case reports journal}, volume = {11}, number = {}, pages = {319-323}, pmid = {30519120}, issn = {1179-142X}, abstract = {Melioidosis, an infectious disease caused by Burkholderia pseudomallei, has recently gained importance as an emerging infectious disease in Indonesia. Reports of this infection in Indonesia are limited, although cases have been reported in Makassar, South Sulawesi. We report a case of cutaneous melioidosis caused by pan-drug-resistant, moderate biofilm-producer strain of B. pseudomallei in a diabetic patient. To the best of our knowledge, this is the first case of melioidosis caused by multidrug resistant and biofilm-former strain of B. pseudomallei being reported from Yogyakarta Province, Indonesia. The patient was successfully treated with abscess drainage and debridement, including total contact casting and no antibiotic treatment.}, } @article {pmid30508627, year = {2019}, author = {Ko, SJ and Kang, NH and Kim, MK and Park, J and Park, E and Park, GH and Kang, TW and Na, DE and Park, JB and Yi, YE and Jeon, SH and Park, Y}, title = {Antibacterial and anti-biofilm activity, and mechanism of action of pleurocidin against drug resistant Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {70-78}, doi = {10.1016/j.micpath.2018.11.052}, pmid = {30508627}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects/physiology ; DNA/metabolism ; Fish Proteins/*pharmacology ; Gentian Violet/analysis ; Membrane Potentials/drug effects ; Microbial Viability/drug effects ; Microscopy ; Protein Binding ; Staining and Labeling ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {The abuse of antibiotics has resulted in the emergence of multi-drug-resistant bacteria. Staphylococcus aureus is a frequent cause of infections, and antibiotic-resistant S. aureus has become a serious problem. Antimicrobial peptides play an important role in innate immunity and are attracting increasing attention as alternative antibiotics. In a previous study, pleurocidin, derived from winter flounder, was identified as a 25-amino acid antimicrobial peptide with no cytotoxicity toward mammalian cells and low hemolytic activity. In the present study, pleurocidin was observed to exhibit antimicrobial activity against gram-positive and gram-negative bacteria, especially against drug resistant S. aureus. Pleurocidin retained its antibacterial activity against drug resistant S. aureus in the presence of a physiological salt concentration. Membrane depolarization assays and propidium iodide uptake indicated that pleurocidin kills bacteria by damaging the integrity of the bacterial membrane. DNA binding assays revealed that pleurocidin binds to DNA. Thus, pleurocidin targets not only the bacterial membrane, but also their DNA. S. aureus biofilms have become a serious problem because of increased resistance to antibiotics. Therefore, we investigated the effect of pleurocidin on biofilm inhibition and eradication using crystal violet staining and microscopic observation. Pleurocidin inhibited and eradicated biofilms at low concentrations. Taken together, the results suggested that pleurocidin is a promising candidate therapeutic agent to treat drug-resistant bacteria and biofilm-related infections.}, } @article {pmid30508626, year = {2019}, author = {Kamarudheen, N and Rao, KVB}, title = {Fatty acyl compounds from marine Streptomyces griseoincarnatus strain HK12 against two major bio-film forming nosocomial pathogens; an in vitro and in silico approach.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {121-130}, doi = {10.1016/j.micpath.2018.11.050}, pmid = {30508626}, issn = {1096-1208}, mesh = {A549 Cells ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology/toxicity ; Aquatic Organisms/*chemistry ; Biofilms/*drug effects ; Cell Survival/drug effects ; Fatty Acids/chemistry/isolation & purification/*pharmacology/toxicity ; Gas Chromatography-Mass Spectrometry ; Humans ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; Streptomyces/*chemistry ; }, abstract = {The perpetual increase in the resistance offered by biofilm-forming nosocomial pathogens has become a critical clinical challenge. Marine Streptomyces sps present a promising future of novel compounds with novel applications. We focus on the anti-biofilm activity of marine Streptomyces against two major nosocomial pathogens from clinical samples, Pseudomonas aeruginosa and Staphylococcus aureus. Herein, Streptomyces griseoincarnatus, a species known to harbour alkaline protease inhibitors and anti-tumour compounds were found to exhibit anti-biofilm activity. The study progresses to decipher the anti-biofilm potential of the extract as 82.657 ± 1.1002% against P. aeruginosa and 78.973 ± 1.672% against S. aureus at 100 μg/mL. The strain under study, S. griseoincarnatus HK 12 (accession no MF100857) has revealed the presence of certain fatty acyl compounds namely, 13Z-Octadecenal, 9Z-Octadecenal, Arachidic acid, Tetracosanoic acid and Erucic acid by GC-MS screening. Furthermore, the active compounds were docked against the quorum sensing system, LasI. The compound 13Z-Octadecenal was found to bind to the conserved sites of substrate binding with a binding energy of -1.90 kcal/mol thus, affirming the inhibitory activity of the fatty acyl compound. These active compounds were previously reported to be a part of active extracts exhibiting relevant antagonistic activities, but this so far is the first time they are found possessing anti-biofilm activity. Interestingly, the toxicity level of the extract at a high concentration of 500 μg/mL is as low as 11.5% when tested against human lung cancer lines, A549. Thus the report highlights the evidence of the potential of S griseoincarnatus HK12 to be an active and safe anti-biofilm agent.}, } @article {pmid30508474, year = {2019}, author = {Jamwal, A and Sharma, K and Chauhan, R and Bansal, S and Goel, G}, title = {Evaluation of commercial probiotic lactic cultures against biofilm formation by Cronobacter sakazakii.}, journal = {Intestinal research}, volume = {17}, number = {2}, pages = {192-201}, pmid = {30508474}, issn = {1598-9100}, abstract = {BACKGROUND/AIMS: Cronobacter sakazakii, an emergent pathogen is considered as a major concern to infants and neonates fed on reconstituted powdered infant milk formula. In conjunction with many other factors, biofilm forming capacity adds to its pathogenic potential. In view of the facts that infants are at highest risk to C. sakazakii infections, and emerging antibiotic resistance among pathogens, it is imperative to evaluate probiotic cultures for their efficacy against C. sakazakii. Therefore, pure probiotic strains were isolated from commercial probiotic products and tested for their antimicrobial and anti-biofilm activities against C. sakazakii.

METHODS: A total of 6 probiotic strains were tested for their antibiotic susceptibility followed by antimicrobial activity using cell-free supernatant (CFS) against C. sakazakii. The inhibitory activity of CFS against biofilm formation by C. sakazakii was determined using standard crystal violet assay and microscopic observations.

RESULTS: All the probiotic strains were sensitive to ampicillin, tetracycline, vancomycin and carbenicillin whereas most of the strains were resistant to erythromycin and novobiocin. Four of the 6 probiotic derived CFS possessed antimicrobial activity against C. sakazakii at a level of 40 μL. A higher biofilm inhibitory activity (>80%) was observed at initial stages of biofilm formation with weaker activity during longer incubation upto 48 hours (50%-60%).

CONCLUSIONS: The study indicated the efficacy of isolated commercial probiotics strains as potential inhibitor of biofilm formation by C. sakazakii and could be further explored for novel bioactive molecules to limit the emerging infections of C. sakazakii.}, } @article {pmid30507674, year = {2019}, author = {Verstraelen, H and Swidsinski, A}, title = {The biofilm in bacterial vaginosis: implications for epidemiology, diagnosis and treatment: 2018 update.}, journal = {Current opinion in infectious diseases}, volume = {32}, number = {1}, pages = {38-42}, doi = {10.1097/QCO.0000000000000516}, pmid = {30507674}, issn = {1473-6527}, mesh = {Anti-Bacterial Agents/*therapeutic use ; *Biofilms ; Female ; Humans ; Microbiota/drug effects/physiology ; Vagina/microbiology ; Vaginosis, Bacterial/diagnosis/drug therapy/*epidemiology/*microbiology ; }, abstract = {PURPOSE OF REVIEW: Bacterial vaginosis is conventionally appreciated as a temporary community disturbance of the vaginal microbiota, though really involving self-organization as a resilient biofilm community. We will briefly review here how recent findings on this matter may affect practice and research in this field.

RECENT FINDINGS: The rapidly expanding literature base on the vaginal microbiome is largely based on 16S ribosomal ribonucleic acid (rRNA) and cpn60 gene sequencing, with few studies accounting thus far for spatial microbiota organization. The putative sexually transmitted disease profile of bacterial vaginosis inferred from epidemiologic research, may concur with its biofilm nature, notably involving spread of dispersed cells or cell aggregates between hosts. De novo biofilm formation in response to prolonged vaginal ecosystem pressure should be considered a pathogenetic model as well. Biofilm assays may not only aid epidemiologic research, but also add to monitoring therapeutic efficacy of novel treatments. Therapeutic research thus far is largely confined to inhibition of in-vitro biofilm formation, though a recent innovative clinical trial involved a combinational approach of metronidazole and a surfactant, specifically aiming for the biofilm.

SUMMARY: Bacterial vaginosis research will further benefit from biofilm assays complementing taxonomy-based data, and this already translates in a novel treatment paradigm.}, } @article {pmid30506795, year = {2019}, author = {Kamińska, M and Aliko, A and Hellvard, A and Bielecka, E and Binder, V and Marczyk, A and Potempa, J and Delaleu, N and Kantyka, T and Mydel, P}, title = {Effects of statins on multispecies oral biofilm identify simvastatin as a drug candidate targeting Porphyromonas gingivalis.}, journal = {Journal of periodontology}, volume = {90}, number = {6}, pages = {637-646}, pmid = {30506795}, issn = {1943-3670}, support = {R21 DE023207/DE/NIDCR NIH HHS/United States ; R01 DE022597/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms ; *Diabetes Mellitus, Type 2 ; Fusobacterium nucleatum ; Humans ; *Hydroxymethylglutaryl-CoA Reductase Inhibitors ; Porphyromonas gingivalis ; Simvastatin ; }, abstract = {BACKGROUND: Statins effectively reduce risk of cardiovascular-related morbidity and mortality in patients with hyperlipidemia, hypertension, or type 2 diabetes. In addition to lowering cholesterol levels, several studies have attributed statins with immunomodulatory and bactericidal properties. Therefore, the aim of this study was to investigate statins' antimicrobial activity against periodontal homeostasis bacteria.

METHODS: Statin effect on bacterial growth was tested using planktonic monocultures and multibacterial biofilms. The latter consisted of five microbial species (Porphyromonas gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Tannerella forsythia, and Streptococcus gordonii) associated with dysbiosis of the oral microbiota underlying establishment and perpetuation of periodontitis.

RESULTS: All four tested statins efficiently inhibited P. gingivalis growth and significantly decreased the cumulative bacterial load in developing and established biofilms. Simvastatin was most efficient and decreased P. gingivalis counts more than 1,300-fold relative to the control.

CONCLUSIONS: These findings suggest that similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microbiome from a dysbiotic to a more homeostatic one. Simvastatin, being highly effective against P. gingivalis while not affecting commensal microbiota, possesses many properties qualifying it as a potential adjunctive treatment for chronic periodontitis. Further studies are needed to evaluate whether similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microflora from dysbiotic to a more homeostatic one.}, } @article {pmid30505734, year = {2018}, author = {Herati, AS and Lo, EM}, title = {Penile prosthesis biofilm formation and emerging therapies against them.}, journal = {Translational andrology and urology}, volume = {7}, number = {6}, pages = {960-967}, pmid = {30505734}, issn = {2223-4691}, abstract = {Infections are among the most feared and devastating complications of penile prosthesis infections, often requiring surgical exploration and explantation are prosthesis infections. While the rate of infections have decreased due to antibiotic prophylaxis, antiseptic device preparation, increased sterility in implantation techniques and device modifications, infections still occur at a rate of 1-3%. This article reviews the formation of biofilms on penile prostheses and novel, experimental methods to prevent and eradicate them.}, } @article {pmid30504968, year = {2018}, author = {Robb, AJ and Vinogradov, S and Danell, AS and Anderson, E and Blackledge, MS and Melander, C and Hvastkovs, EG}, title = {Electrochemical Detection of Small Molecule Induced Pseudomonas aeruginosa Biofilm Dispersion.}, journal = {Electrochimica acta}, volume = {268}, number = {}, pages = {276-282}, pmid = {30504968}, issn = {0013-4686}, support = {R01 DE022350/DE/NIDCR NIH HHS/United States ; R01 GM055769/GM/NIGMS NIH HHS/United States ; }, abstract = {A simple electrochemical assay to monitor the dispersion of Pseudomonas aeruginosa PA01 biofilm is described. Pyrolytic graphite (PG) electrodes were modified with P. aeruginosa PA01 using layer-by-layer (LbL) methods. The presence of the bacteria on the electrodes was directly monitored using square wave voltammetry (SWV) via the electrochemical reduction of electroactive phenazine compounds expressed by the bacteria, which indicate the presence of biofilm. Upon treatment of bacteria-modified electrodes with a 2-aminoimidazole (2-AI) derivative with known Pseudomonas anti-biofilm properties, the bacteria-related electrochemical reduction peaks decreased in a concentration dependent manner, indicating dispersal of the biofilm on the electrode surface. A similar 2-AI compound with negligible anti-biofilm activity was used as a comparative control and produced muted electrochemical results. Electrochemical responses mirrored previously established bioassay-derived half maximal inhibition concentration (IC50) and half maximal effective concentration (EC50) values.. Biofilm dispersal detection via the electrochemical response was validated by monitoring crystal violet absorbance after its release from electrode confined P. aeruginosa biofilm. Mass spectrometry data showing multiple redox active phenazine compounds are presented to provide insight into the surface reaction complexity. Overall, we present a very simple assay to monitor the anti-biofilm activity of compounds of interest.}, } @article {pmid30502966, year = {2019}, author = {Sánchez, MC and Toledano-Osorio, M and Bueno, J and Figuero, E and Toledano, M and Medina-Castillo, AL and Osorio, R and Herrera, D and Sanz, M}, title = {Antibacterial effects of polymeric PolymP-n Active nanoparticles. An in vitro biofilm study.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {35}, number = {1}, pages = {156-168}, doi = {10.1016/j.dental.2018.11.015}, pmid = {30502966}, issn = {1879-0097}, mesh = {*Anti-Bacterial Agents ; Biofilms ; Fusobacterium nucleatum ; Humans ; *Nanoparticles ; Streptococcus oralis ; }, abstract = {OBJECTIVE: to study the antibacterial effect of polymeric PolymP-n Active nanoparticles using an in vitro subgingival biofilm model.

METHODS: Hydroxyapatite discs coated with five modalities of nanoparticles (NPs): NPs, NPs doped with zinc, calcium, silver and doxycycline, PBS as control, and Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were studied in a static in vitro biofilm model (12, 24, 48, and 72h). Nano-roughness of the different disc surfaces (SRa, in nm) and morphological characteristic of the biofilms (thickness (μm) and bacterial viability) were studied by different microscopy modalities. Quantitative Polymerase Chain Reaction was used to assess the effect of the nanoparticles on the bacterial load (colony forming unit per milliliter) (CFUmL[-1]). Analysis of variance and post-hoc testing with T3 Dunnett́s, and Student Newman Keuls correction was used. Results were considered statistically significant at p<0.05.

RESULTS: Surfaces containing the different nanoparticles showed significant increments in roughness when compared to controls (p<0.05). A similar biofilm formation and dynamics was observed, although reductions in bacterial viability were detected in biofilms in contact with the different nanoparticles, more pronounced with silver and doxycycline NPs. Doxycycline-NPs biofilms resulted in unstructured biofilm formation and significantly lower number of the six species when compared with the other nanoparticles specimens and controls (p<0.001 in all cases).

SIGNIFICANCE: Polymeric PolymP-n Active nanoparticles when combined with silver and doxycycline showed a significant antibacterial effect when tested in an in vitro subgingival biofilm model.}, } @article {pmid30517641, year = {2019}, author = {Abad, L and Tafani, V and Tasse, J and Josse, J and Chidiac, C and Lustig, S and Ferry, T and Diot, A and Laurent, F and Valour, F}, title = {Evaluation of the ability of linezolid and tedizolid to eradicate intraosteoblastic and biofilm-embedded Staphylococcus aureus in the bone and joint infection setting.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {74}, number = {3}, pages = {625-632}, doi = {10.1093/jac/dky473}, pmid = {30517641}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Granulocyte Precursor Cells/*microbiology ; Humans ; Linezolid/*pharmacology ; Microbial Sensitivity Tests ; Models, Theoretical ; Osteoarthritis/*microbiology ; Oxazolidinones/*pharmacology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects ; Tetrazoles/*pharmacology ; }, abstract = {OBJECTIVES: Prolonged use of linezolid for bone and joint infection (BJI) is limited by its long-term toxicity. The better safety profile of tedizolid, a recently developed oxazolidinone, could offer an alternative. However, its efficacy against biofilm-embedded and intracellular Staphylococcus aureus, the two main bacterial reservoirs associated with BJI chronicity, is unknown.

METHODS: Using three S. aureus strains (6850 and two clinical BJI isolates), linezolid and tedizolid were compared regarding their ability: (i) to target the S. aureus intracellular reservoir in an in vitro model of osteoblast infection, using three concentrations increasing from the bone concentration reached with standard therapeutic doses (Cbone = 2.5 × MIC; Cplasm = 10 × MIC; Cmax = 40 × MIC); (ii) to eradicate mature biofilm [minimal biofilm eradication concentration (MBEC)]; and (iii) to prevent biofilm formation [biofilm MIC (bMIC) and confocal microscopy].

RESULTS: Linezolid and tedizolid weakly reduced the intracellular inoculum of S. aureus in a strain-dependent manner despite the similar MICs for the tested strains, but improved cell viability even in the absence of an intracellular bactericidal effect. Conversely, linezolid and tedizolid were ineffective in eradicating mature biofilm formed in vitro, with MBEC >2000 and >675 mg/L, respectively. bMICs of tedizolid were 4-fold lower than those of linezolid for all strains.

CONCLUSIONS: Linezolid and tedizolid alone are not optimal candidates to target bacterial phenotypes associated with chronic forms of BJI. Despite weak intracellular activity, they both reduce infection-related cytotoxicity, suggesting a role in modulating intracellular expression of staphylococcal virulence factors. Although inactive against biofilm-embedded S. aureus, both-but particularly tedizolid-are able to prevent biofilm formation.}, } @article {pmid30517529, year = {2018}, author = {Rampelotto, RF and Lorenzoni, VV and Silva, DDC and Coelho, SS and Wust, V and Garzon, LR and Nunes, MS and Meneghetti, B and Brites, PC and Hörner, M and Hörner, R}, title = {Assessment of different methods for the detection of biofilm production in coagulase-negative staphylococci isolated from blood cultures of newborns.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {51}, number = {6}, pages = {761-767}, doi = {10.1590/0037-8682-0171-2018}, pmid = {30517529}, issn = {1678-9849}, mesh = {Bacteremia/*microbiology ; Biofilms/*growth & development ; Congo Red ; Culture Techniques ; Genotype ; Humans ; Infant, Newborn ; Polymerase Chain Reaction ; Sensitivity and Specificity ; Staphylococcal Infections/*diagnosis/microbiology ; Staphylococcus/genetics/*isolation & purification ; }, abstract = {INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detection of biofilm formation in 176 CoNS isolates from blood cultures of newborns.

METHODS: The presence of the icaACD genes was assessed by polymerase chain reaction (PCR), and biofilm formation was assessed on congo red agar (CRA), by the tube method (TM), and on tissue culture plates (TCP).

RESULTS: Of the 176 CoNS isolates, 30.1% expressed icaACD and 11.4% expressed icaAD. The CRA assay and TM showed that 42% and 38.6% of the isolates were biofilm producing, respectively. On TCP, 40.9% of the isolates produced biofilms; 21% were weakly adherent and 19.9% were strongly adherent. When compared to the gold standard technique (PCR), the CRAassay showed 79% sensitivity and 84% specificity (kappa = 0.64), TM showed 78% sensitivity and 89% specificity (kappa = 0.68), and TCP showed 99% sensitivity and 100% specificity (kappa = 0.99).

CONCLUSIONS: In this study, ~42% of CoNS isolates produced biofilms, and the presence of icaACD was associated with a greater capacity to form biofilms. Compared to the other phenotypic methodologies, TCP is an ideal procedure for routine laboratory use.}, } @article {pmid30517484, year = {2018}, author = {Souza, BM and Santos, DMSD and Magalhães, AC}, title = {Antimicrobial and Anti-Caries Effect of New Glass Ionomer Cement on Enamel Under Microcosm Biofilm Model.}, journal = {Brazilian dental journal}, volume = {29}, number = {6}, pages = {599-605}, doi = {10.1590/0103-6440201802163}, pmid = {30517484}, issn = {1806-4760}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Brazil ; Cariostatic Agents/*pharmacology ; Cattle ; Dental Enamel/*drug effects ; *Dental Restoration, Permanent ; Glass Ionomer Cements/*pharmacology ; Humans ; In Vitro Techniques ; Maleates ; Materials Testing ; Saliva/microbiology ; Streptococcus mutans ; Streptococcus sobrinus ; Surface Properties ; }, abstract = {The occurrence of caries lesions adjacent to restorations is a serious problem in Dentistry. Therefore, new antimicrobial restorative materials could help to prevent recurrent carious lesions. This study evaluated the effect of a new glass ionomer cement (Ion Z) on the viability of a microcosm biofilm and on the development of enamel demineralization. Enamel samples were filled with the following materials (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) and D) no restoration (control). The samples were then exposed to human saliva mixed with McBain saliva (1:50) containing 0.2% sucrose for 14 days. The live and dead bacteria were quantified by fluorescence using a confocal laser-scanning microscope. The enamel demineralization was analyzed using transverse microradiography (TMR). The data were submitted to ANOVA/Tukey or Kruskal-Wallis/Dunn test (p<0.05). Ion Z induced a higher percentage of dead bacteria (60.96±12.0%) compared to the other groups (Maxxion R: 39.8±6.7%, Ketac Fil Plus: 43.7±9.71% and control 46.3±9.5%). All materials significantly reduced the average mineral loss compared to control (Ion-Z 25.0±4.2%vol, Maxxion R 23.4±8.0%vol, Ketac Fil Plus 30.7±7.7 and control 41.2±6.6%vol). Ion-Z was the only material able to significantly improve the mineral content at the surface layer (Zmax: 63.5±18.2%vol) compared to control (38.9±11.3%vol). Ion-Z shows antimicrobial potential, but its anti-caries effect was similar to the other materials, under this model.}, } @article {pmid30515580, year = {2019}, author = {Rodrigues, SV and Laviniki, V and Borges, KA and Furian, TQ and Moraes, HLS and Nascimento, VP and Salle, CTP}, title = {Biofilm Formation by Avian Pathogenic Escherichia coli is Not Related to In Vivo Pathogenicity.}, journal = {Current microbiology}, volume = {76}, number = {2}, pages = {194-199}, pmid = {30515580}, issn = {1432-0991}, mesh = {Animals ; Biofilms/*growth & development ; Brazil ; Cellulose/analysis ; Chickens/microbiology ; Escherichia coli/pathogenicity/*physiology ; Escherichia coli Infections/microbiology/*veterinary ; Escherichia coli Proteins/metabolism ; Fimbriae, Bacterial/metabolism ; Poultry/*microbiology ; Poultry Diseases/diagnosis/microbiology ; Virulence ; Virulence Factors/*analysis ; }, abstract = {Avian pathogenic Escherichia coli (APEC) is one of the pathogens that most concerns the poultry industry worldwide due to the economic losses it can cause. APEC persistence and survival, both in the environment and in the host, may be a consequence of biofilm-producing capabilities. The aim of this study was to evaluate APEC strains' biofilm production and its relationship to in vivo pathogenicity. Two hundred thirty-eight APEC isolates from three different origins (broiler bedding material, cellulite lesions, and respiratory diseases) were selected. The in vivo pathogenicity index (PI) was determined. Biofilm formation was evaluated using a microplate assay with analysis of colony morphology in Congo Red agar in order to detect the phenotypic expression of curli fimbriae and cellulose. Regarding biofilm production, it was observed that 55.8% of the strains produced biofilms. In the morphological test, 88.2% of the isolates expressed one or both components at one of the temperatures at least, and 11.8% of the isolates did not express curli or cellulose. Cellulose production was significantly higher at 25 °C. On the other hand, curli production was significantly higher at 37 °C. The study data indicate that there is no association between biofilm production and in vivo pathogenicity.}, } @article {pmid30515144, year = {2018}, author = {Moshiri, J and Kaur, D and Hambira, CM and Sandala, JL and Koopman, JA and Fuchs, JR and Gunn, JS}, title = {Identification of a Small Molecule Anti-biofilm Agent Against Salmonella enterica.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2804}, pmid = {30515144}, issn = {1664-302X}, support = {P30 CA016058/CA/NCI NIH HHS/United States ; R01 AI116917/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilm formation is a common strategy utilized by bacterial pathogens to establish persistence in a host niche. Salmonella enterica serovar Typhi, the etiological agent of Typhoid fever, relies on biofilm formation in the gallbladder to chronically colonize asymptomatic carriers, allowing for transmission to uninfected individuals. S. enterica serovar Typhimurium utilizes biofilms to achieve persistence in human and animal hosts, an issue of both clinical and agricultural importance. Here, we identify a compound that selectively inhibits biofilm formation in both S. Typhi and S. Typhimurium serovars at early stages of biofilm development with an EC50 of 21.0 and 7.4 μM, respectively. We find that this compound, T315, also reduces biofilm formation in Acinetobacter baumannii, a nosocomial and opportunistic pathogen with rising antibiotic resistance. T315 treatment in conjunction with sub-MIC dosing of ciprofloxacin further reduces S. enterica biofilm formation, demonstrating the potential of such combination therapies for therapeutic development. Through synthesis of two biotin-labeled T315 probes and subsequent pull-down and proteomics analysis, we identified a T315 binding target: WrbA, a flavin mononucleotide-dependent NADH:quinone oxidoreductase. Using a S. Typhimurium strain lacking WrbA we demonstrate that this factor contributes to endogenous S. enterica biofilm formation processes and is required for full T315 anti-biofilm activity. We suggest WrbA as a promising target for further development of anti-biofilm agents in Salmonella, with potential for use against additional bacterial pathogens. The development of anti-biofilm therapeutics will be essential to combat chronic carriage of Typhoid fever and thus accomplish a meaningful reduction of global disease burden.}, } @article {pmid30515135, year = {2018}, author = {Wan, N and Wang, H and Ng, CK and Mukherjee, M and Ren, D and Cao, B and Tang, YJ}, title = {Bacterial Metabolism During Biofilm Growth Investigated by [13]C Tracing.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2657}, pmid = {30515135}, issn = {1664-302X}, abstract = {This study investigated the metabolism of Pseudomonas aeruginosa PAO1 during its biofilm development via microscopy imaging, gene expression analysis, and [13]C-labeling. First, dynamic labeling was employed to investigate glucose utilization rate in fresh biofilms (thickness 40∼60 micrometer). The labeling turnover time of glucose-6-P indicated biofilm metabolism was substantially slower than planktonic cells. Second, PAO1 was cultured in continuous tubular biofilm reactors or shake flasks. Then [13]C-metabolic flux analysis of PAO1 was performed based on the isotopomer patterns of proteinogenic amino acids. The results showed that PAO1 biofilm cells during growth conserved the flux features as their planktonic mode. (1) Glucose could be degraded by two cyclic routes (the TCA cycle and the Entner-Doudoroff-Embden-Meyerhof-Parnas loop) that facilitated NAD(P)H supplies. (2) Anaplerotic pathways (including pyruvate shunt) increased flux plasticity. (3) Biofilm growth phenotype did not require significant intracellular flux rewiring (variations between biofilm and planktonic flux network, normalized by glucose uptake rate as 100%, were less than 20%). (4) Transcription analysis indicated that key catabolic genes in fresh biofilm cells had expression levels comparable to planktonic cells. Finally, PAO1, Shewanella oneidensis (as the comparing group), and their c-di-GMP transconjugants (with different biofilm formation capabilities) were [13]C-labeled under biofilm reactors or planktonic conditions. Analysis of amino acid labeling variances from different cultures indicated Shewanella flux network was more flexibly changed than PAO1 during its biofilm formation.}, } @article {pmid30514888, year = {2018}, author = {Roscetto, E and Contursi, P and Vollaro, A and Fusco, S and Notomista, E and Catania, MR}, title = {Antifungal and anti-biofilm activity of the first cryptic antimicrobial peptide from an archaeal protein against Candida spp. clinical isolates.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {17570}, pmid = {30514888}, issn = {2045-2322}, support = {16-CSP-UNINA-007//Compagnia di San Paolo/International ; 16-CSP-UNINA-007//Compagnia di San Paolo/International ; }, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Antimicrobial Cationic Peptides/isolation & purification/*pharmacology ; Archaea/metabolism ; Archaeal Proteins/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Microbial Sensitivity Tests ; }, abstract = {Candida species cause cutaneous and systemic infections with a high mortality rate, especially in immunocompromised patients. The emergence of resistance to the most common antifungal drugs, also due to biofilm formation, requires the development of alternative antifungal agents. The antimicrobial peptide VLL-28, isolated from an archaeal transcription factor, shows comparable antifungal activity against 10 clinical isolates of Candida spp. Using a fluoresceinated derivative of this peptide, we found that VLL-28 binds to the surface of planktonic cells. This observation suggested that it could exert its antifungal activity by damaging the cell wall. In addition, analyses performed on biofilms via confocal microscopy revealed that VLL-28 is differentially active on all the strains tested, with C. albicans and C. parapsilosis being the most sensitive ones. Notably, VLL-28 is the first example of an archaeal antimicrobial peptide that is active towards Candida spp. Thus, this points to archaeal microorganisms as a possible reservoir of novel antifungal agents.}, } @article {pmid30508707, year = {2019}, author = {Farhat, NM and Javier, L and Van Loosdrecht, MCM and Kruithof, JC and Vrouwenvelder, JS}, title = {Role of feed water biodegradable substrate concentration on biofouling: Biofilm characteristics, membrane performance and cleanability.}, journal = {Water research}, volume = {150}, number = {}, pages = {1-11}, doi = {10.1016/j.watres.2018.11.054}, pmid = {30508707}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Membranes, Artificial ; Osmosis ; Water ; *Water Purification ; }, abstract = {Biofouling severely impacts operational performance of membrane systems increasing the cost of water production. Understanding the effect of critical parameters of feed water such as biodegradable substrate concentration on the developed biofilm characteristics enables development of more effective biofouling control strategies. In this study, the effect of substrate concentration on the biofilm characteristics was examined using membrane fouling simulators (MFSs). A feed channel pressure drop (PD) increase of 200 mbar was used as a benchmark to study the developed biofilm. The amount and characteristics of the formed biofilm were analysed in relation to membrane performance indicators: feed channel pressure drop and permeate flux. The effect of the characteristics of the biofilm developed at three substrate concentrations on the removal efficiency of the different biofilms was evaluated applying acid/base cleaning. Results showed that a higher feed water substrate concentration caused a higher biomass amount, a faster PD increase, but a lower permeate flux decline. The permeate flux decline was affected by the spatial location and the physical characteristics of the biofilm rather than the total amount of biofilm. The slower growing biofilm developed at the lowest substrate concentration was harder to remove by NaOH/HCl cleanings than the biofilm developed at the higher substrate concentrations. Effective biofilm removal is essential to prevent a fast biofilm regrowth after cleaning. While substrate limitation is a generally accepted biofouling control strategy delaying biofouling, development of advanced cleaning methods to remove biofilms formed under substrate limited conditions is of paramount importance.}, } @article {pmid30511304, year = {2019}, author = {Wang, T and Huang, W and Duan, Q and Wang, J and Cheng, H and Shao, J and Li, F and Wu, D}, title = {Sodium houttuyfonate in vitro inhibits biofilm dispersion and expression of bdlA in Pseudomonas aeruginosa.}, journal = {Molecular biology reports}, volume = {46}, number = {1}, pages = {471-477}, pmid = {30511304}, issn = {1573-4978}, support = {81503115//National Natural Science Foundation of China/ ; 81603167//National Natural Science Foundation of China/ ; 81573725//National Natural Science Foundation of China/ ; }, mesh = {Alkanes/metabolism/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Pseudomonas aeruginosa/*drug effects/metabolism ; Sulfites/metabolism/*pharmacology ; }, abstract = {Biofilm dispersion is the last step in the development of biofilms, and allows bacteria to spawn novel biofilms in new locales. In the previous studies, we found that sodium houttuyfonate (SH) is effective at inhibiting biofilm formation and motility of Pseudomonas aeruginosa. Here, we investigated the effect of SH against the biofilm dispersion of P. aeruginosa by an in vitro model. The results show that the plant derivative, SH, could effectively inhibit both biofilm dispersion of P. aeruginosa, and gene and protein expression of the key biofilm regulator BdlA in a dose-dependent manner. Furthermore, our presented results suggest that SH can penetrate into the biofilm of P. aeruginosa to repress the biofilm life cycle. Therefore, these results indicate that the antimicrobial activity of SH may be partially due to its ability to disrupt biofilm dispersion in P. aeruginosa.}, } @article {pmid30509729, year = {2019}, author = {Huang, H and Fan, X and Peng, C and Geng, J and Ding, L and Zhang, X and Ren, H}, title = {Linking microbial respiratory activity with phospholipid fatty acid of biofilm from full-scale bioreactors.}, journal = {Bioresource technology}, volume = {272}, number = {}, pages = {599-605}, doi = {10.1016/j.biortech.2018.10.051}, pmid = {30509729}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Fatty Acids/*metabolism ; Phospholipids/*metabolism ; }, abstract = {Deficiency of researches on biotic community-driven biofilm activity makes biofilm regulation lack of quantitative response for decades. Based on three full-scale aerobic bioreactors in wastewater treatment plants, this study for the first time linked microbial respiratory activity with phospholipid fatty acid (PLFA) of biofilm developed on fixed and suspended carriers. Results showed that C16:00, C18:00, C16:1, ω7c, C18:1, ω7c, C12:00 and C18:1ω9c were top six biomarkers of PLFA among different sources of samples and Gram-negative bacteria (G-) was more abundant than Gram-positive bacteria (G+) with average G-/G+ of 2.98. It's interesting to find defective revealing of PLFA-based biofilm activity by specific oxygen uptake rate (SOUR). Further modeling indicated that C16:00 achieved the optimal quantitative response to STOUR with the best model of composite, growth, or exponential curve (R[2] = 0.416, p = 0.005). This research was promising to provide important reference for biofilm regulation and accurate control of biofilm-based process.}, } @article {pmid30502698, year = {2019}, author = {Liang, X and Peng, LH and Zhang, S and Zhou, S and Yoshida, A and Osatomi, K and Bellou, N and Guo, XP and Dobretsov, S and Yang, JL}, title = {Polyurethane, epoxy resin and polydimethylsiloxane altered biofilm formation and mussel settlement.}, journal = {Chemosphere}, volume = {218}, number = {}, pages = {599-608}, doi = {10.1016/j.chemosphere.2018.11.120}, pmid = {30502698}, issn = {1879-1298}, mesh = {Animals ; Biofilms/*growth & development ; Biomass ; Chlorophyll A/metabolism ; Cyanobacteria/growth & development ; Diatoms ; *Dimethylpolysiloxanes ; Ecotoxicology/methods ; *Epoxy Resins ; Microbiota/*physiology ; Mytilus/*physiology ; *Polyurethanes ; }, abstract = {In many environments, biofilms are a major mode and an emergent form of microbial life. Biofilms play crucial roles in biogeochemical cycling and invertebrate recruitment in marine environments. However, relatively little is known about how marine biofilms form on different substrata and about how these biofilms impact invertebrate recruitment. Here, we performed a comparative analysis of a 28-day-old biofilm community on non-coated (a control glass) and coated substrata (polyurethane (PU), epoxy resin (EP) and polydimethylsiloxane (PDMS)) and examined the settlement of Mytilus coruscus plantigrades on these biofilms. PU, EP and PDMS deterred the development of marine biofilms by reducing the biofilm biomass including the biofilm dry weight, cell density of the bacteria and diatoms and chlorophyll a concentrations. Further analysis of bacterial community revealed that EP altered the bacterial community composition compared with that on the glass substrata by reducing the relative abundance of Ruegeria (Alphaproteobacteria) and by increasing the relative abundance of Methylotenera (Betaproteobacteria) and Cyanobacteria in the biofilms. However, bacterial communities developed on PU and PDMS, as well as glass and PU, EP and PDMS did not exhibit differences from each other. The M. coruscus settlement rates on biofilms on PU, EP and PDMS were reduced by 20-41% compared with those on the glass after 28 days. Thus, the tested coatings impacted the development of marine biofilms by altering the biofilm biomass and/or the bacterial community composition. The mussel settlements decreased in the biofilms that formed on the coatings compared with those on non-coated glass.}, } @article {pmid30502600, year = {2019}, author = {Wang, Y and Zhu, Y and Sun, P and Liu, J and Zhu, N and Tang, J and Wong, PK and Fan, H and Wu, Y}, title = {Augmenting nitrogen removal by periphytic biofilm strengthened via upconversion phosphors (UCPs).}, journal = {Bioresource technology}, volume = {274}, number = {}, pages = {105-112}, doi = {10.1016/j.biortech.2018.11.079}, pmid = {30502600}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Cyanobacteria ; Denitrification ; Nitrogen/*isolation & purification ; Phosphorus/chemistry ; Wastewater/chemistry ; }, abstract = {The application of periphytic biofilm in removing nitrogen from water is limited by the fluctuating nitrogen concentration. Here, we delineate a novel approach to enhance periphytic biofilm performance in nitrogen removal via upconversion luminescence of upconversion phosphors (UCPs). Nitrogen removal rates (14 d) in high nitrogen wastewater (26 mg/L) were significantly improved to 58.6% and 61.4% by UCPs doped with Pr[3+] and Li[+] and UCPs doped with Pr[3+], respectively, and to 95.1% and 95.9% in low nitrogen surface water (2 mg/L), respectively. The stimulation of UCPs optimized the microbial community structure in the periphytic biofilms, and also resulted in good acclimation to use different carbon sources. The enhanced synergic action of cyanobacterial biomass, ratio of Gram +ve to Gram -ve bacteria and carbon source metabolic capacity contributed to the improved nitrogen removal. This novel approach is promising in nitrogen removal from wastewater and surface water with fluctuating initial nitrogen concentration.}, } @article {pmid30500736, year = {2019}, author = {de Araújo, LCA and da Purificação-Júnior, AF and da Silva, SM and Lopes, ACS and Veras, DL and Alves, LC and Dos Santos, FB and Napoleão, TH and Dos Santos Correia, MT and da Silva, MV and Oliva, MLV and de Oliveira, MBM}, title = {In vitro evaluation of mercury (Hg[2+]) effects on biofilm formation by clinical and environmental isolates of Klebsiella pneumoniae.}, journal = {Ecotoxicology and environmental safety}, volume = {169}, number = {}, pages = {669-677}, doi = {10.1016/j.ecoenv.2018.11.036}, pmid = {30500736}, issn = {1090-2414}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial/drug effects/genetics ; Environmental Pollutants/*toxicity ; Hospitals ; Humans ; Klebsiella pneumoniae/*drug effects/genetics/pathogenicity ; Mercury/*toxicity ; Microbial Sensitivity Tests ; Virulence Factors/genetics ; }, abstract = {The increase in urbanization and industrialization has contributed to the contamination of different environments by means of xenobiotic compounds, such as heavy metals, causing changes in microbial communities. Among these metals, the Mercury (Hg[2+]) is one the most prevalent toxic metals for the environment The present study aimed to evaluate the effect of mercury on the formation of biofilm by environmental (collected from urban stream water) and clinical isolates of Klebsiella pneumoniae. In addition, antibiotic resistance, virulence factors, and genetic diversity were investigated. Taxonomic identity of eight isolates (one reference, two clinical, and five environmental isolates) was performed by MALDI-TOF-MS, while the antibiotic susceptibility profile was assessed by the disc diffusion method. The ability to form biofilms was evaluated by culture on Congo red agar and by crystal violet staining. Biofilm structure was analyzed by scanning electron microscopy. The hydrophobicity profile and the presence of the virulence genes cps, fimH, and mrkD was investigated. The presence of merA and its relationship with antimicrobial resistance were also assessed. The identity of all isolates was confirmed by MALDI-TOF-MS, and different profiles of resistance to mercury and antibiotics as well as of biofilm formation were identified for the clinical and environmental isolates. All isolates were hydrophilic and positive for the virulence genes cps, fimH, and mrkD; only the clinical isolate K36-A2 was positive for merA. The diversity of the isolates was confirmed by ERIC-PCR, which revealed high heterogeneity among the isolates. In conclusion, the data demonstrate that the investigated isolates present different responses to exposure to Hg[2+] and correspond to distinct populations of K. pneumoniae disseminated in the investigated environment. The data obtained in this work will aid in understanding the mechanisms of survival of this pathogen under adverse conditions.}, } @article {pmid30500410, year = {2019}, author = {Freire, NB and Magalhães, TC and Nunes Soares, RA and da Costa, MM and Gouveia, GV}, title = {Nutritional interference for phenotypic biofilm quantification in Aeromonas spp. isolates containing the fla gene.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {198-201}, doi = {10.1016/j.micpath.2018.11.044}, pmid = {30500410}, issn = {1096-1208}, mesh = {Aeromonas/genetics/*growth & development/isolation & purification/metabolism ; Animals ; Biofilms/*growth & development ; Culture Media/*chemistry ; Fish Diseases/microbiology ; Fishes ; Flagella/*genetics ; Glucose/*metabolism ; Gram-Negative Bacterial Infections/microbiology/veterinary ; Polymerase Chain Reaction ; }, abstract = {The Aeromonas genus has several virulence factors associated with the development of diseases in aquatic organisms, leading to losses in aquaculture. One of these factors is the flagella's formation which allows the biofilm's formation that provides the microorganisms a greater pathogenicity, greater protection to certain substances such as antibiotics. The aim of the study was to verify the presence of the fla gene, related to biofilm production in isolates of Aeromonas spp. from fishes and also to determine the best quantification condition of phenotypic biofilm production in vitro. Polymerase Chain Reactions were performed to obtain the amplification of the region comprising the fla gene. To determine the best condition for the production biofilm, the microplate adhesion test was carried out under different concentrations of TSB broth and it combined with glucose. Of the 43 isolates of Aeromonas spp. analyzed, 28 were positive for the fla gene and, in the quantification of the biofilm, all these were able to form biofilm in the TSB broth without dilution and without addition of glucose, being this the best condition tested. It was observed that the isolates of Aeromonas spp. analyzed have potential for biofilm formation, and hence potential for virulence.}, } @article {pmid30499405, year = {2018}, author = {Selvaraj, C and Priya, RB and Singh, SK}, title = {Exploring the Biology and Structural Architecture of Sortase Role on Biofilm Formation in Gram Positive Pathogens.}, journal = {Current topics in medicinal chemistry}, volume = {18}, number = {29}, pages = {2462-2480}, doi = {10.2174/1568026619666181130133916}, pmid = {30499405}, issn = {1873-4294}, mesh = {Amino Acid Sequence ; Bacterial Proteins/chemistry/*metabolism ; *Biofilms ; Cell Wall/metabolism ; Cysteine Endopeptidases/chemistry/*metabolism ; Gram-Positive Bacteria/*metabolism ; Membrane Proteins/chemistry/metabolism ; }, abstract = {Gram-positive bacteria signify a surface organelle that decorates the cell surfaces using Sortase enzymes. The mechanism of SrtC links to the formation of amide or peptide bonds between cell surface proteins that sorting signal to strategically positioned amino groups. Sorting signals linked to peptidoglycan function as the principal architects of the cell wall and facilitate each microbe to effectively interact with its host environment. These enzymes play a fundamental role in microbial physiology and interestingly, sequence analysis on Gram-positive bacteria implies that approximately 60% of sortases are categorized into six families, and from that SrtA and SrtC are widely investigated in various literature. Sortase felicitates several functions that include adhesins, internalin's, blood clotting, immune evasion factors and transporters for nutrients across the microbial cell wall envelope. Recent evidence has proved that removal of Sortase genes tends to loss of host cell adhesion mechanism and inhibition of Biofilms. So that, blocking the Sortase enzyme is a powerful target and due to the receptor availability in all Gram-positive types, it is so called as a universal drug target for gram-positive pathogens. Sortase enzymes have been intensely studied for anti-infective studies and this review focus the mechanisms of surface protein anchoring to the cell wall envelope by sortases and highlight how it plays a strong role as a drug target.}, } @article {pmid30498307, year = {2018}, author = {Premamalini, T and Anitha, S and Mohanapriya, K and Kindo, AJ}, title = {Evaluation of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method for assessing biofilm formation in vitro by Trichosporon spp.}, journal = {Journal of laboratory physicians}, volume = {10}, number = {4}, pages = {380-386}, pmid = {30498307}, issn = {0974-2727}, abstract = {BACKGROUND: Invasive infections due to Trichosporon spp. have increased recently and are frequently associated with indwelling medical devices. Such infections which are associated with biofilm formation do not respond to the routinely used antifungal agents and are often persistent, associated with high mortality rate. Various methods have been described by researchers to evaluate and quantify the biofilm formation.

AIM: This study was conducted to compare two methods of biofilm production by Trichosporon sp, i.e., test tube method with crystal violet (CV) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.

MATERIALS AND METHODS: Seventy-two clinical isolates of Trichosporon spp. collected from various sources were considered for the study. The identity of all the isolates was genotypically confirmed by Trichosporon-specific polymerase chain reaction (PCR). The isolates were further speciated phenotypically using biochemical profile and growth characteristics which identified the isolates as Trichosporon asahii (64/72), Trichosporon asteroides (5/72), Trichosporon cutaneum (2/72), and Trichosporon mucoides (1/72). Biofilm production was then evaluated and compared by test tube-CV method and MTT assay.

RESULTS: All the Trichosporon isolates produced biofilm by MTT assay, whereas only 42 (53.6%) of the isolates were detected to be biofilm producers by CV method. Furthermore, MTT assay could differentiate better between weak and moderate biofilm producers as compared to CV method.

CONCLUSION: Hence, MTT assay is a reliable method for quantification of biofilm produced by Trichosporon spp. using 96-well microtiter plate.}, } @article {pmid30498247, year = {2018}, author = {Ge, G and Zhao, J and Li, X and Ding, X and Chen, A and Chen, Y and Hu, B and Wang, S}, title = {Author Correction: Effects of influent COD/N ratios on nitrous oxide emission in a sequencing biofilm batch reactor for simultaneous nitrogen and phosphorus removal.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {17646}, doi = {10.1038/s41598-018-36019-6}, pmid = {30498247}, issn = {2045-2322}, abstract = {A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.}, } @article {pmid30497590, year = {2019}, author = {Bevilacqua, A and Racioppo, A and Sinigaglia, M and Speranza, B and Campaniello, D and Corbo, MR}, title = {A low-power ultrasound attenuation improves the stability of biofilm and hydrophobicity of Propionibacterium freudenreichii subsp. freudenreichii DSM 20271 and Acidipropionibacterium jensenii DSM 20535.}, journal = {Food microbiology}, volume = {78}, number = {}, pages = {104-109}, doi = {10.1016/j.fm.2018.10.010}, pmid = {30497590}, issn = {1095-9998}, mesh = {Acids/metabolism ; Biofilms/*growth & development ; Hydrogen-Ion Concentration ; *Hydrophobic and Hydrophilic Interactions ; Microbial Viability ; Permeability ; Propionibacterium/*physiology ; Propionibacterium freudenreichii/growth & development/*physiology ; Sonication ; *Ultrasonics ; }, abstract = {The main topic of this paper was to study the effect of ultrasound-attenuation (US) on the surface properties of propionibacteria (Acidipropionibacterium jensenii DSM 20535 and Propionibacterium freudenreichii DSM 20271). A preliminary screening was done by using different power levels (40 and 60%) and treatment times (4, 6, and 8 min); immediately after sonication, acidification and viable count were tested. The best combinations to avoid post-acidification after 6 h were the following: A. jensenii DSM 20535: power, 40%; time, 8 min; P. freudenreichii subsp. freudenreichii DSM 20271: power, 60%; time, 4 min. Moreover, the effect of US on the growth patterns, surface properties (biofilm formation and hydrophobicity), resistance to some selected antibiotics, and release of intracellular components was evaluated; the experiments were done immediately after the treatment. US-treatment improved the stability of biofilm after 5-7 days, caused an increase of hydrophobicity (from 15 to 27%) immediately after sonication, and determined an increase of cell permeability, as suggested by the release of intracellular components within 24 h and by the increased sensitivity to some antibiotics. This paper is the first report on US-attenuation on propionibacteria and could the background for future researches to modulate the surface properties of these microorganisms.}, } @article {pmid30496836, year = {2019}, author = {Yan, X and Gu, S and Cui, X and Shi, Y and Wen, S and Chen, H and Ge, J}, title = {Antimicrobial, anti-adhesive and anti-biofilm potential of biosurfactants isolated from Pediococcus acidilactici and Lactobacillus plantarum against Staphylococcus aureus CMCC26003.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {12-20}, doi = {10.1016/j.micpath.2018.11.039}, pmid = {30496836}, issn = {1096-1208}, mesh = {Anti-Infective Agents/isolation & purification/*pharmacology ; Bacterial Adhesion/*drug effects ; Bacterial Proteins/biosynthesis ; Biofilms/*drug effects/growth & development ; Biological Products/isolation & purification/pharmacology ; Gene Expression Profiling ; Gentian Violet/analysis ; Lactobacillus plantarum/*chemistry ; Microscopy, Electron, Scanning ; Pediococcus acidilactici/*chemistry ; Quorum Sensing/drug effects ; Staining and Labeling ; Staphylococcus aureus/*drug effects/physiology ; Surface-Active Agents/isolation & purification/*pharmacology ; }, abstract = {Biosurfactants (BS) are amphipathic compounds produced by diverse groups of microorganisms exhibiting various biological activities. The current study aimed to assess antimicrobial, anti-adhesive and anti-biofilm activities of BS isolated from lactic acid bacteria (LAB), including Pediococcus acidilactici and Lactobacillus plantarum against Staphylococcus aureus CMCC 26003 in vitro. Cell-bound BS from both Pediococcus acidilactici and Lactobacillus plantarum were extracted, and their surface activities were evaluated by oil spreading assay. As quantified by crystal violet method, BS inhibited adhesion and biofilm formation of Staphylococcus aureus in a dose-dependent manner. The above findings were further supported by results of scanning electron microscopy. These two kinds of BS affect expressions of biofilm-related genes (cidA, icaA, dltB, agrA, sortaseA and sarA) and interfere with the release of signaling molecules (AI-2) in quorum sensing systems. Biological activities observed for BS produced by tested LAB suggest prospects for their use against Staphylococcus aureus biofilm-related infections.}, } @article {pmid30489241, year = {2018}, author = {Frevert, W and Wright, TW and Farmer, KW and Yang, Q and Struk, AM and Schultz, G}, title = {Evaluation of Biofilms on Explanted Shoulder Prostheses Using Functional Biofilm Assay and Scanning Electron Microscopy.}, journal = {Journal of surgical orthopaedic advances}, volume = {27}, number = {3}, pages = {171-177}, pmid = {30489241}, issn = {1548-825X}, mesh = {Aged ; Aged, 80 and over ; *Biofilms ; Culture Techniques ; Device Removal ; Female ; Humans ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; Prosthesis-Related Infections ; Reoperation ; Shoulder Prosthesis/*microbiology ; Sonication ; }, abstract = {Successfully treating shoulder arthroplasty infection requires diagnosis and bacterial identification. Higher incidence of infection with low-virulence bacteria makes this challenging. This study evaluates shoulder prostheses for infection using sonication and a functional biofilm assay. Nineteen patients undergoing revision shoulder arthroplasty were followed prospectively. Periprosthetic tissue and prosthetic components were obtained during the revision and evaluated with a functional biofilm assay. Results were compared with conventional cultures and laboratory results. Hardware samples were analyzed with scanning electron microscopy. Six of the 19 cases demonstrated growth on the biofilm assay. Three of these had positive conventional culture results and met Musculoskeletal Infection Society (MSIS) criteria for infection. Two other cases met MSIS criteria but demonstrated negative assay and conventional culture results. Of the six cases with positive assay results, three demonstrated evidence of biofilm on scanning electron microscopy. The biofilm assay identifies infections not recognized by traditional culture or MSIS criteria. (Journal of Surgical Orthopaedic Advances 27(3):171-177, 2018).}, } @article {pmid30488449, year = {2019}, author = {Swimberghe, RCD and Coenye, T and De Moor, RJG and Meire, MA}, title = {Biofilm model systems for root canal disinfection: a literature review.}, journal = {International endodontic journal}, volume = {52}, number = {5}, pages = {604-628}, doi = {10.1111/iej.13050}, pmid = {30488449}, issn = {1365-2591}, support = {BOF15/GOA/022//Ghent University Special Research Fund/ ; }, mesh = {Biofilms ; *Dental Pulp Cavity ; Dentin ; Disinfection ; Enterococcus faecalis ; Humans ; Root Canal Irrigants ; *Root Canal Therapy ; }, abstract = {The aim of this review was to present an overview of laboratory root canal biofilm model systems described in the endodontic literature and to critically appraise the various factors that constitute these models. The electronic databases MEDLINE, Web of Science and EMBASE were searched up to and including December 2016 to identify laboratory studies using endodontic biofilm models. The following search terms were used in various combinations: biofilm, root canal, in vitro, endodontic, bacteria, root canal infection model, colony-forming unit. Only English papers from journals with an impact factor were selected. The records were screened by two reviewers, and full-text articles were assessed according to pre-defined criteria. The following data were extracted from the included studies: the microbial composition of the biofilm, the substrate, growth conditions, validation and quantification. Seventy-seven articles met the inclusion criteria. In the majority (86%) of the studies, a monospecies biofilm was cultured. In two studies, a dual-species biofilm was grown; others cultivated a multispecies biofilm, containing at least three species. Enterococcus faecalis was the most frequently used test species (in 79% of all studies, 92% of the monospecies studies). Four studies used an inoculum derived directly from the oral cavity. Human dentine was the most frequently used substratum (88% of the studies). Incubation times differed considerably, ranging from one to seventy days. The most common quantification method (in 87% of the studies) was bacterial culturing, followed by microscopy techniques. The variation in laboratory root canal biofilm model systems is notable. Because of substantial variation in experimental parameters, it is difficult to compare results between studies. This demonstrates the need for a more standardized approach and a validated endodontic biofilm model.}, } @article {pmid30487781, year = {2018}, author = {Panda, S and Singh, DV}, title = {Biofilm Formation by ica-Negative Ocular Isolates of Staphylococcus haemolyticus.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2687}, pmid = {30487781}, issn = {1664-302X}, abstract = {Staphylococcus haemolyticus is the second most frequently isolated CoNS from ocular infections and human blood cultures. In this study, we examined 18 ocular S. haemolyticus isolates for their capacity to form biofilm and conducted detachment assay to determine the composition of the biofilm matrix and involvement of various elements in cell lysis. PCR identified the presence of biofilm-associated genes, and ica operon and CLSM visualized the components of the biofilm matrix. We found that PIA-independent biofilm formation is the characteristic feature of S. haemolyticus isolates, irrespective of the sources of isolation, and protein or DNA or both are the major components of the biofilm matrix. Cell lysis enabling DNA release was an essential step for biofilm attachment during the initial stages of biofilm development. The srtA transcript expression study indicates its role in the early stages of biofilm development. We found the presence of antibiotic resistance genes in the eDNA and gDNA thus suggesting the possible role of biofilm in horizontal gene transfer of antibiotic resistance determinants. The overall study indicates that S. haemolyticus formed the biofilm comprising of protein or DNA or both and srtA play a role in the initial development of biofilm.}, } @article {pmid30486500, year = {2018}, author = {Mempin, M and Hu, H and Chowdhury, D and Deva, A and Vickery, K}, title = {The A, B and C's of Silicone Breast Implants: Anaplastic Large Cell Lymphoma, Biofilm and Capsular Contracture.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {12}, pages = {}, pmid = {30486500}, issn = {1996-1944}, abstract = {Breast implantation either for cosmetic or reconstructive e purposes is one of the most common procedures performed in plastic surgery. Biofilm infection is hypothesised to be involved in the development of both capsular contracture and anaplastic large cell lymphoma (ALCL). Capsular contracture is one of the principal reasons for breast revision surgery and is characterised by the tightening and hardening of the capsule surrounding the implant, and ALCL is an indolent lymphoma found only in women with textured implants. We describe the types of breast implants available with regard to their surface characteristics of surface area and roughness and how this might contribute to capsular contracture and/or biofilm formation. The pathogenesis of capsular contracture is thought to be due to biofilm formation on the implant, which results in on-going inflammation. We describe the current research into breast implant associated ALCL and how implant properties may affect its pathogenesis, with ALCL only occurring in women with textured implants.}, } @article {pmid30486494, year = {2018}, author = {Cadavid, E and Robledo, SM and Quiñones, W and Echeverri, F}, title = {Induction of Biofilm Formation in Klebsiella pneumoniae ATCC 13884 by Several Drugs: The Possible Role of Quorum Sensing Modulation.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {7}, number = {4}, pages = {}, pmid = {30486494}, issn = {2079-6382}, support = {SUSTAINABILITY PROGRAM//Universidad de Antioquia/ ; Doctoral Formation Program (567-2012)//Departamento Administrativo de Ciencia, Tecnología e Innovación/ ; }, abstract = {Bacterial resistance is caused by several biochemical factors, the formation of biofilm being one of the main causes. This process is triggered by Quorum Sensing (QS), through the production of endogenous molecules, although other substances such as natural products can also do this. In this work, we aimed to determine whether some drugs are involved in the induction of biofilm formation in Klebsiella pneumoniae ATCC 13884, and thus, increase bacterial resistance. For this, the effect of 22 drugs on K. pneumoniae ATCC 13884 growth was determined at sub-plasmatic concentrations; the production of autoinducer lactones was established by HPLC and with a biosensor. The induction of biofilm formation was determined through crystal violet assay at 585 nm in a microplate reader and using urethral catheters. According to the in vitro assays, some drugs were found to induce biofilm formation in K. pneumoniae ATCC 13884. The effect of acetaminophen, hydrochlorothiazide, and progesterone stood out. The first drug caused several changes in the biochemistry of K. pneumoniae ATCC 13884 related to QS: high synthesis of N-hexanoyl-homoserine lactone, increasing bacterial populations by 27% and biofilm formation by 49%, and a more gentamicin resistant biofilm. Furthermore, it increased the colonization area of urethral catheters. Hydrochlorothiazide showed the biggest increase in the induction of biofilm formation of 51%, and progesterone displayed the greatest ability to provoke bacterial mass adherence but had no effects on K. pneumoniae ATCC 13884 bacterial population growth.}, } @article {pmid30486310, year = {2018}, author = {Rodrigues, S and Paillard, C and Van Dillen, S and Tahrioui, A and Berjeaud, JM and Dufour, A and Bazire, A}, title = {Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study.}, journal = {Pathogens (Basel, Switzerland)}, volume = {7}, number = {4}, pages = {}, pmid = {30486310}, issn = {2076-0817}, abstract = {Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A flow cell system was employed to grow biofilms to obtain both structural and transcriptomic views of the biofilms. We found that 3615 genes were differentially expressed, confirming that biofilm and planktonic lifestyles are very different. As expected, the differentially expressed genes included those involved in biofilm formation, such as motility- and polysaccharide synthesis-related genes. The data show that quorum sensing is probably mediated by the AI-2/LuxO system in V. tapetis biofilms. The expression of genes encoding the Type VI Secretion System and associated exported proteins are strongly induced, suggesting that V. tapetis activates this virulence factor when living in biofilm.}, } @article {pmid30483847, year = {2019}, author = {Huang, H and Peng, C and Peng, P and Lin, Y and Zhang, X and Ren, H}, title = {Towards the biofilm characterization and regulation in biological wastewater treatment.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {3}, pages = {1115-1129}, doi = {10.1007/s00253-018-9511-6}, pmid = {30483847}, issn = {1432-0614}, support = {51878336//National Natural Science Foundation of China/ ; 51608254//National Natural Science Foundation of China/ ; BK20160655//Natural Science Foundation of Jiangsu Province/ ; }, mesh = {Bacteria/*growth & development/metabolism ; Biofilms/*growth & development ; Bioreactors ; Wastewater/analysis/*microbiology ; Water Purification/methods ; }, abstract = {There is an increasing need for application of biofilm process in the upcycling of wastewater treatment plants all around the world in recent years, yet there are few literatures on summarizing wastewater biofilm during the life cycle. In particular, there is a vacancy on characterization at various stages of biofilm and its regulation. This review provided a whole look at biofilm formation and its development, accompanied by microbial physiology, ecology, and activity, where the initialization of biofilm formation and its characterization were stressed. The new progresses on biofilm physio-ecology analysis and methods on evaluating microbial activity were summarized, while it is worth mentioning that the concept of aging biofilm was also presented. Furthermore, regulations methods of biofilm were reviewed and future research trends on biofilm control were prospected, aiming at guiding biofilm control in biofilm-based wastewater treatment.}, } @article {pmid30483521, year = {2018}, author = {Mayer, FL and Sánchez-León, E and Kronstad, JW}, title = {A chemical genetic screen reveals a role for proteostasis in capsule and biofilm formation by Cryptococcus neoformans.}, journal = {Microbial cell (Graz, Austria)}, volume = {5}, number = {11}, pages = {495-510}, pmid = {30483521}, issn = {2311-2638}, abstract = {Pathogenic microorganisms employ specialized virulence factors to cause disease. Biofilm formation and the production of a polysaccharide capsule are two important virulence factors in Cryptococcus neoformans, the fungal pathogen that causes meningoencephalitis. Here, we show that the bipolar disorder drug lithium inhibits formation of both virulence factors by a mechanism involving dysregulation of the ubiquitin/proteasome system. By using a chemical genetics approach and bioinformatic analyses, we describe the cellular landscape affected by lithium treatment. We demonstrate that lithium affects many different pathways in C. neoformans, including the cAMP/protein kinase A, inositol biosynthesis, and ubiquitin/proteasome pathways. By analyzing mutants with defects in the ubiquitin/proteasome system, we uncover a role for proteostasis in both capsule and biofilm formation. Moreover, we demonstrate an additive influence of lithium and the proteasome inhibitor bortezomib in inhibiting capsule production, thus establishing a link between lithium activity and the proteasome system. Finally, we show that the lithium-mimetic drug ebselen potently blocks capsule and biofilm formation, and has additive activity with lithium or bortezomib. In summary, our results illuminate the impact of lithium on C. neoformans, and link dysregulation of the proteasome to capsule and biofilm inhibition in this important fungal pathogen.}, } @article {pmid30483223, year = {2018}, author = {Liu, L and Wu, R and Zhang, J and Li, P}, title = {Overexpression of luxS Promotes Stress Resistance and Biofilm Formation of Lactobacillus paraplantarum L-ZS9 by Regulating the Expression of Multiple Genes.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2628}, pmid = {30483223}, issn = {1664-302X}, abstract = {Probiotics have evoked great interest in the past years for their beneficial effects. The aim of this study was to investigate whether luxS overexpression promotes the stress resistance of Lactobacillus paraplantarum L-ZS9. Here we show that overexpression of luxS gene increased the production of autoinducer-2 (AI-2, quorum sensing signal molecule) by L. paraplantarum L-ZS9. At the same time, overexpression of luxS promoted heat-, bile salt-resistance and biofilm formation of the strain. RNAseq results indicated that multiple genes encoding transporters, membrane proteins, and transcriptional regulator were regulated by luxS. These results reveal a new role for LuxS in promoting stress resistance and biofilm formation of probiotic starter.}, } @article {pmid30481378, year = {2019}, author = {Cai, Z and Li, Y and Wang, Y and Chen, S and Jiang, S and Ge, H and Lei, L and Huang, X}, title = {Disinfect Porphyromonas gingivalis Biofilm on Titanium Surface with Combined Application of Chlorhexidine and Antimicrobial Photodynamic Therapy.}, journal = {Photochemistry and photobiology}, volume = {95}, number = {3}, pages = {839-845}, doi = {10.1111/php.13060}, pmid = {30481378}, issn = {1751-1097}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/administration & dosage/*pharmacology ; Colony Count, Microbial ; Disinfectants/administration & dosage/*pharmacology ; Humans ; Microscopy, Electron, Scanning ; *Photochemotherapy ; Porphyromonas gingivalis/*drug effects/growth & development/isolation & purification ; Surface Properties ; Titanium/*chemistry ; }, abstract = {Various antimicrobial modalities have been proposed to treat peri-implantitis but resulted in limited outcomes. The aim of this in vitro study was to evaluate the disinfection efficacy of combined application of chlorhexidine digluconate (CHX) and antimicrobial photodynamic therapy (aPDT) of titanium surfaces previously contaminated with Porphyromonas gingivalis biofilm. P. gingivalis biofilms were grown on 32 polished and 32 sandblasted large-grit acid-etched (SLA) titanium surfaces. Titanium disks were allocated into four groups as follows: (1) immersed in phosphate-buffered saline (PBS), (2) immersed in 0.2% CHX, (3) application of aPDT and (4) immersed in 0.2% CHX and subsequent aPDT. Residual bacteria were determined by microbial culture analysis and by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) imaging. Combination protocol (CHX+ aPDT) was the most effective in eradicating P. gingivalis (P < 0.05) on both polished and SLA surfaces. There was no significant difference in the number of remaining P. gingivalis between polished titanium disks and the SLA ones in four groups (P > 0.05). Under the limitation of this study, combined technique of preceding application of CHX and subsequent aPDT was shown to be an efficient method in reducing P. gingivalis numbers in both polished and SLA titanium surfaces.}, } @article {pmid30479660, year = {2018}, author = {Liu, D and Yang, Z and Chen, Y and Zhuang, W and Niu, H and Wu, J and Ying, H}, title = {Clostridium acetobutylicum grows vegetatively in a biofilm rich in heteropolysaccharides and cytoplasmic proteins.}, journal = {Biotechnology for biofuels}, volume = {11}, number = {}, pages = {315}, pmid = {30479660}, issn = {1754-6834}, abstract = {BACKGROUND: Biofilms are cell communities wherein cells are embedded in a self-produced extracellular polymeric substances (EPS). The biofilm of Clostridium acetobutylicum confers the cells superior phenotypes and has been extensively exploited to produce a variety of liquid biofuels and bulk chemicals. However, little has been known about the physiology of C. acetobutylicum in biofilm as well as the composition and biosynthesis of the EPS. Thus, this study is focused on revealing the cell physiology and EPS composition of C. acetobutylicum biofilm.

RESULTS: Here, we revealed a novel lifestyle of C. acetobutylicum in biofilm: elimination of sporulation and vegetative growth. Extracellular polymeric substances and wire-like structures were also observed in the biofilm. Furthermore, for the first time, the biofilm polysaccharides and proteins were isolated and characterized. The biofilm contained three heteropolysaccharides. The major fraction consisted of predominantly glucose, mannose and aminoglucose. Also, a great variety of proteins including many non-classically secreted proteins moonlighting as adhesins were found considerably present in the biofilm, with GroEL, a S-layer protein and rubrerythrin being the most abundant ones.

CONCLUSIONS: This study evidenced that vegetative C. acetobutylicum cells rather than commonly assumed spore-forming cells were essentially the solvent-forming cells. The abundant non-classically secreted moonlighting proteins might be important for the biofilm formation. This study provides the first physiological and molecular insights into C. acetobutylicum biofilm which should be valuable for understanding and development of the biofilm-based processes.}, } @article {pmid30478229, year = {2019}, author = {Zhu, X and Rice, SA and Barraud, N}, title = {Nitric Oxide and Iron Signaling Cues Have Opposing Effects on Biofilm Development in Pseudomonas aeruginosa.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {3}, pages = {}, pmid = {30478229}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Iron/*metabolism ; Nitric Oxide/*metabolism ; Oligopeptides/biosynthesis ; Polysaccharides, Bacterial/metabolism ; Pseudomonas aeruginosa/genetics/growth & development/*physiology ; }, abstract = {While both iron and nitric oxide (NO) are redox-active environmental signals shown to regulate biofilm development, their interaction and roles in regulating biofilms have not been fully elucidated. In this study, exposure of Pseudomonas aeruginosa biofilms to exogenous NO inhibited the expression of iron acquisition-related genes and the production of the siderophore pyoverdine. Furthermore, supplementation of the culture medium with high levels of iron (100 μM) counteracted NO-induced biofilm dispersal by promoting the rapid attachment of planktonic cells. In the presence of iron, biofilms were found to disperse transiently to NO, while the freshly dispersed cells reattached rapidly within 15 min. This effect was not due to the scavenging of NO by free iron but involved a cellular response induced by iron that led to the elevated production of the exopolysaccharide Psl. Interestingly, most Psl remained on the substratum after treatment with NO, suggesting that dispersal involved changes in the interactions between Psl and P. aeruginosa cells. Taken together, our results suggest that iron and NO regulate biofilm development via different pathways, both of which include the regulation of Psl-mediated attachment. Moreover, the addition of an iron chelator worked synergistically with NO in the dispersal of biofilms.IMPORTANCE Nitric oxide (NO), which induces biofilm dispersal, is a promising strategy for biofilm control in both clinical and industrial contexts. However, competing environmental signals may reduce the efficacy of NO. The results presented here suggest that the presence of iron represents one such environmental cue that antagonizes the activity of NO as a biofilm-dispersing agent. Based on this understanding, we developed a strategy to enhance dispersal by combining NO with an iron-scavenging agent. Overall, this study links two important environmental signals, iron and NO, with their roles in biofilm development and suggests new ways for improving the use of NO in biofilm control strategies.}, } @article {pmid30477481, year = {2018}, author = {Vogt, CM and Hilbe, M and Ackermann, M and Aguilar, C and Eichwald, C}, title = {Mouse intestinal microbiota reduction favors local intestinal immunity triggered by antigens displayed in Bacillus subtilis biofilm.}, journal = {Microbial cell factories}, volume = {17}, number = {1}, pages = {187}, pmid = {30477481}, issn = {1475-2859}, support = {265862/FP-7-KBBE//PARAVAC European Commission Grant/ ; }, mesh = {Animals ; Antigens, Bacterial/*metabolism ; Bacillus subtilis/*physiology ; *Biofilms ; *Gastrointestinal Microbiome ; *Immunity ; Immunity, Humoral ; Intestines/*immunology/*microbiology ; Mice, Inbred BALB C ; Spores, Bacterial ; }, abstract = {BACKGROUND: We previously engineered Bacillus subtilis to express an antigen of interest fused to TasA in a biofilm. B. subtilis has several properties such as sporulation, biofilm formation and probiotic ability that were used for the oral application of recombinant spores harboring Echinococcus granulosus paramyosin and tropomyosin immunogenic peptides that resulted in the elicitation of a specific humoral immune response in a dog model.

RESULTS: In order to advance our understanding of the research in oral immunization practices using recombinant B. subtilis spores, we describe here an affordable animal model. In this study, we show clear evidence indicating that a niche is required for B. subtilis recombinant spores to colonize the densely populated mice intestinal microbiota. The reduction of intestinal microbiota with an antibiotic treatment resulted in a positive elicitation of local humoral immune response in BALB/c mice after oral application of recombinant B. subtilis spores harboring TasA fused to E. granulosus (102-207) EgTrp immunogenic peptide. Our results were supported by a lasting prevalence of spores in mice feces up to 50 days after immunization and by the presence of specific secretory IgA, isolated from feces, against E. granulosus tropomyosin.

CONCLUSIONS: The reduction of mouse intestinal microbiota allowed the elicitation of a local humoral immune response in mice after oral application with spores of B. subtilis harboring immunogenic peptides against E. granulosus.}, } @article {pmid30477343, year = {2018}, author = {Wang, J and Yu, Z and Xu, Z and Hu, S and Li, Y and Xue, X and Cai, Q and Zhou, X and Shen, J and Lan, Y and Cheng, C}, title = {Antimicrobial mechanism and the effect of atmospheric pressure N2 plasma jet on the regeneration capacity of Staphylococcus aureus biofilm.}, journal = {Biofouling}, volume = {34}, number = {8}, pages = {935-949}, doi = {10.1080/08927014.2018.1530350}, pmid = {30477343}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Atmospheric Pressure ; Biofilms/*drug effects ; Microbial Viability/drug effects ; Nitrogen/*pharmacology ; Plasma Gases/*pharmacology ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/*drug effects/growth & development/metabolism ; }, abstract = {This study systematically assessed the inactivation mechanism on Staphylococcus aureus biofilms by a N2 atmospheric-pressure plasma jet and the effect on the biofilm regeneration capacity from the bacteria which survived, and their progenies. The total bacterial populations were 7.18 ± 0.34 log10 CFU ml[-1] in biofilms and these were effectively inactivated (>5.5-log10 CFU ml[-1]) within 30 min of exposure. Meanwhile, >80% of the S. aureus biofilm cells lost their metabolic capacity. In comparison, ∼20% of the plasma-treated bacteria entered a viable but non-culturable state. Moreover, the percentage of membrane-intact bacteria declined to ∼30%. Scanning electron microscope images demonstrated cell shrinkage and deformation post-treatment. The total amount of intracellular reactive oxygen species was observed to have significantly increased in membrane-intact bacterial cells with increasing plasma dose. Notably, the N2 plasma treatment could effectively inhibit the biofilm regeneration ability of the bacteria which survived, leading to a long-term phenotypic response and dose-dependent inactivation effect on S. aureus biofilms, in addition to the direct rapid bactericidal effect.}, } @article {pmid30477243, year = {2018}, author = {Blöcher, R and Rodarte Ramírez, A and Castro-Escarpulli, G and Curiel-Quesada, E and Reyes-Arellano, A}, title = {Design, Synthesis, and Evaluation of Alkyl-Quinoxalin-2(1H)-One Derivatives as Anti-Quorum Sensing Molecules, Inhibiting Biofilm Formation in Aeromonas caviae Sch3.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {12}, pages = {}, pmid = {30477243}, issn = {1420-3049}, support = {240808//Consejo Nacional de Ciencia y Tecnología/ ; SIP20181765//Instituto Politécnico Nacional/ ; }, mesh = {Aeromonas caviae/*drug effects/growth & development ; Anti-Bacterial Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/*drug effects ; Chemistry Techniques, Synthetic ; Drug Design ; Magnetic Resonance Spectroscopy ; Quinoxalines/chemical synthesis/*chemistry/*pharmacology ; Quorum Sensing/*drug effects ; }, abstract = {With the increasing antibiotic resistance of bacterial strains, alternative methods for infection control are in high demand. Quorum sensing (QS) is the bacterial communication system based on small molecules. QS is enables bacterial biofilm formation and pathogenic development. The interruption of QS has become a target for drug discovery, but remains in the early experimental phase. In this study, we synthesized a set of six compounds based on a scaffold (alkyl-quinoxalin-2(1H)-one), new in the anti-QS of Gram-negative bacteria Aeromonas caviae Sch3. By quantifying biofilm formation, we were able to monitor the effect of these compounds from concentrations of 1 to 100 µM. Significant reduction in biofilm formation was achieved by 3-hexylylquinoxalin-2(1H)-one (11), 3-hexylylquinoxalin-2(1H)-one-6-carboxylic acid (12), and 3-heptylylquinoxalin-2(1H)-one-6-carboxylic acid (14), ranging from 11% to 59% inhibition of the biofilm. This pilot study contributes to the development of anti-QS compounds to overcome the clinical challenge of resistant bacteria strains.}, } @article {pmid30477048, year = {2019}, author = {Galán-Ladero, MÁ and Blanco-Blanco, MT and Fernández-Calderón, MC and Lucio, L and Gutiérrez-Martín, Y and Blanco, MT and Pérez-Giraldo, C}, title = {Candida tropicalis biofilm formation and expression levels of the CTRG ALS-like genes in sessile cells.}, journal = {Yeast (Chichester, England)}, volume = {36}, number = {2}, pages = {107-115}, doi = {10.1002/yea.3370}, pmid = {30477048}, issn = {1097-0061}, support = {GR15025//Junta de Extremadura-FEDER: European Regional Development Fund/International ; }, mesh = {Biofilms/*growth & development ; Blood/microbiology ; Candida tropicalis/*genetics/isolation & purification/metabolism/*physiology ; Candidiasis/microbiology ; *Cell Adhesion ; Cell Adhesion Molecules/chemistry/genetics/*metabolism ; Fungal Proteins/chemistry/genetics/*metabolism ; Gene Expression Profiling ; Humans ; Hydrophobic and Hydrophilic Interactions ; Spain ; Tertiary Care Centers ; Urine/microbiology ; }, abstract = {Candida tropicalis is an emergent pathogen with a high rate of mortality associated with it; however, less is known about its pathogenic capacity. Biofilm formation (BF) has important clinical repercussions, and it begins with adherence to a substrate. The adherence capacity depends principally on the cell surface hydrophobicity (CSH) and, at a later stage, on specific adherence due to adhesins. The ALS family in C. tropicalis, implicated in adhesion and BF, is represented in several CTRG genes. In this study, we determined the biofilm-forming ability, the primary adherence, and the CSH of C. tropicalis, including six isolates from blood and seven from urine cultures. We also compared the expression of four CTRG ALS-like genes (CTRG_01028, CTRG_02293, CTRG_03786, and CTRG_03797) in sessile versus planktonic cells, selected for their possible contribution to BF. All the C. tropicalis strains were biofilm producers, related to its filamentation capacity; all the strains displayed a high adherence ability correlated to the CSH, and all the strains expressed the CTRG genes in both types of growth. Urine isolates present, although not significantly, higher CSH, adherence, and biofilm formation than blood isolates. This study reveals that three CTRG ALS-like genes-except CTRG_03797-were more upregulated in biofilm cells, although with a considerable variation in expression across the strains studied and between the CTRG genes. C. tropicalis present a high biofilm capacity, and the overexpression of several CTRG ALS-like genes in the sessile cells suggests a role by the course of the biofilm formation.}, } @article {pmid30476580, year = {2019}, author = {Qais, FA and Khan, MS and Ahmad, I}, title = {Broad-spectrum quorum sensing and biofilm inhibition by green tea against gram-negative pathogenic bacteria: Deciphering the role of phytocompounds through molecular modelling.}, journal = {Microbial pathogenesis}, volume = {126}, number = {}, pages = {379-392}, doi = {10.1016/j.micpath.2018.11.030}, pmid = {30476580}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Exopeptidases/metabolism ; Glycolipids/metabolism ; Gram-Negative Bacteria/*drug effects ; Hydrophobic and Hydrophilic Interactions/drug effects ; Indoles/pharmacology ; Microbial Sensitivity Tests ; *Models, Molecular ; Molecular Docking Simulation ; Oligopeptides/metabolism ; Peptide Hydrolases/drug effects ; Plant Extracts/chemistry/*pharmacology ; Plant Leaves/chemistry ; Prodigiosin/metabolism ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects ; Tea/*chemistry ; Virulence Factors/metabolism ; }, abstract = {The emerging prevalence of multidrug-resistance in Gram-negative pathogens, due to conventional antimicrobial therapeutics, has led the researchers to emphasize on development of alternative novel strategies to suppress the bacterial virulence and pathogenicity through inhibition of quorum sensing (QS) and biofilms. QS is a bacterial communication system to produce density-dependent response via chemical signalling that controls pathogenesis and biofilms formation. Leaves of green tea are used worldwide as beverage which is also known for its broad-spectrum therapeutic efficacy. In this work, we have identified and characterized the most bioactive faction of green tea extract and evaluated the anti-QS and antibiofilm activity of green tea ethyl acetate fraction (GTEF) i.e. most active fraction, on three different Gram-negative bacterial pathogens. GTEF inhibited the violacein production by >75% in C. violaceum 12472. Many virulence factors of P. aeruginosa PAO1 viz. pyocyanin, pyoverdin, exoprotease, elastase, rhamnolipid production, and swimming motility were remarkably reduced in presence of sub-MICs of GTEF. Moreover, prodigiosin, protease activity, cell surface hydrophobicity, and swimming of S. marcescens MTCC 97 were also decreased significantly by the supplementation of GTEF in culture media. GTEF exhibited broad-spectrum antibiofilm action with >80% reduction in biofilm formation of test pathogens. In silico studies gave a mechanistic insight of action of GTEF. Molecular modelling revealed that phytoconstituents detected by GC/MS exhibited affinity (in order of 10[4] M[-1]) towards AHL synthases (LasI and EsaI). The molecular binding between phytocompounds and receptor proteins (LasR, RhlR, and PqsR) of QS circuit was also energetically favourable (ΔG°≥ 5.0 kcal mol[-1]) and supported by hydrogen bonds and hydrophobic interactions. These compounds were found to be docked in ligand binding domain of CviR and occupied same cavity as that of its antagonist. Squalene and thunbergol interacted with LasA at tartaric acid binding pocket and the complex was strengthened with binding energy -5.9 kcal mol[-1]. Moreover, interaction of thunbergol with biofilm-associated proteins viz. PilT and PilY1, might be disabling the pilus assembly and consequently inhibiting biofilm formation. In vivo validation of results suggested the protective role GTEF against QS-mediated pathogenicity and it might become a novel non-antibiotic QS inhibitor to control bacterial infection.}, } @article {pmid30476044, year = {2019}, author = {Gunasegar, S and Himratul-Aznita, WH}, title = {Nicotine enhances the thickness of biofilm and adherence of Candida albicans ATCC 14053 and Candida parapsilosis ATCC 22019.}, journal = {FEMS yeast research}, volume = {19}, number = {2}, pages = {}, doi = {10.1093/femsyr/foy123}, pmid = {30476044}, issn = {1567-1364}, mesh = {Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Candida parapsilosis/*drug effects/physiology ; Cell Adhesion/*drug effects ; Fungal Proteins/analysis/genetics ; Gene Expression Profiling ; Membrane Glycoproteins/analysis/genetics ; Microbiological Techniques ; Microscopy, Confocal ; Nicotine/*metabolism ; Polysaccharides/metabolism ; Real-Time Polymerase Chain Reaction ; }, abstract = {Candida albicans ATCC 14053 and Candida parapsilosis ATCC 22019 hyphal-wall protein 1 (HWP1) are involved in hyphae formation and pathogenesis. The transcriptional agglutinin-like sequence 3 (ALS3) genes in both species are responsible for the development of biofilm and colonization on tooth surfaces. Therefore, we investigated the expression of HWP1 and ALS3 quantitatively in C. albicans and C. parapsilosis and examined the biofilm structure upon exposure to various nicotine concentrations. In vitro, biofilms of Candida species were developed directly on slides using the Lab-Tek Chamber Slide System and visualized by confocal laser scanning microscopy. Quantitative real-time polymerase chain reaction was used to measure HWP1 and ALS3 expression in C. albicans ATCC 14053 and C. parapsilosis ATCC 22019. The results indicated that nicotine multiplied the number of yeast cells and increased the extracellular polysaccharides of Candida species. We also found that 1-2 mg/mL nicotine could enhance the formation of biofilm. The findings also revealed that the expression of HWP1 and ALS3 in Candida species were increased as the nicotine concentration increased. Therefore, nicotine influences the biofilm development of oral-associated C. albicans ATCC 14053 and C. parapsilosis ATCC 22019.}, } @article {pmid30476034, year = {2019}, author = {Cabello, L and Gómez-Herreros, E and Fernández-Pereira, J and Maicas, S and Martínez-Esparza, MC and de Groot, PWJ and Valentín, E}, title = {Deletion of GLX3 in Candida albicans affects temperature tolerance, biofilm formation and virulence.}, journal = {FEMS yeast research}, volume = {19}, number = {2}, pages = {}, doi = {10.1093/femsyr/foy124}, pmid = {30476034}, issn = {1567-1364}, mesh = {Aldehyde Oxidoreductases/deficiency/*genetics ; Animals ; Biofilms/*growth & development ; Candida albicans/enzymology/genetics/*physiology/*radiation effects ; Candidiasis/microbiology/pathology ; Cell Wall/chemistry ; Disease Models, Animal ; *Gene Deletion ; *Heat-Shock Response ; Hot Temperature ; Hyphae/growth & development ; Mice, Inbred BALB C ; Survival Analysis ; Virulence ; }, abstract = {Candida albicans is a predominant cause of fungal infections in mucosal tissues as well as life-threatening bloodstream infections in immunocompromised patients. Within the human body, C. albicans is mostly embedded in biofilms, which provides increased resistance to antifungal drugs. The glyoxalase Glx3 is an abundant proteomic component of the biofilm extracellular matrix. Here, we document phenotypic studies of a glx3Δ null mutant concerning its role in biofilm formation, filamentation, antifungal drug resistance, cell wall integrity and virulence. First, consistent with its function as glyoxalase, the glx3 null mutant showed impaired growth on media containing glycerol as the carbon source and in the presence of low concentrations of hydrogen peroxide. Importantly, the glx3Δ mutant showed decreased fitness at 37°C and formed less biofilm as compared to wild type and a reintegrant strain. At the permissive temperature of 28°C, the glx3Δ mutant showed impaired filamentation as well as increased sensitivity to Calcofluor white, Congo red, sodium dodecyl sulfate and zymolyase, indicating subtle alterations in wall architecture even though gross quantitative compositional changes were not detected. Interestingly, and consistent with its impaired filamentation, biofilm formation and growth at 37°C, the glx3Δ mutant is avirulent. Our results underline the role of Glx3 in fungal pathogenesis and the involvement of the fungal wall in this process.}, } @article {pmid30474527, year = {2018}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Enhanced Vitamin K (Menaquinone-7) Production by Bacillus subtilis natto in Biofilm Reactors by Optimization of Glucose-based Medium.}, journal = {Current pharmaceutical biotechnology}, volume = {19}, number = {11}, pages = {917-924}, doi = {10.2174/1389201020666181126120401}, pmid = {30474527}, issn = {1873-4316}, mesh = {Bacillus subtilis/*metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Biotechnology/*methods ; Fermentation ; Glucose/*metabolism ; Vitamin K 2/*analogs & derivatives/isolation & purification/metabolism ; }, abstract = {BACKGROUND: Benefits of vitamin K have been reported by many studies recently, due to its ability to reduce the risk of cardiovascular diseases and its potential benefits against osteoporosis. Specifically, menaquinone-7 (MK-7), being the most potent form of vitamin K, has definitely received most of the attention. Currently, solid or static liquid fermentation strategies are utilized for industrial production of MK-7 by Bacillus strains. However, these strategies face fundamental operational and scale-up issues as well as intense pellicle and biofilm formations which is problematic in static liquid fermentation, due to heat and mass transfer inefficiencies they create.

OBJECTIVE: The purpose of this study was to demonstrate that biofilm reactors will overcome the issues associated with suspended cell reactors when using Bacillus strains to produce MK-7. The expectation is that the use of biofilm reactors will result in a significant increase in the production of MK-7.

METHOD: Vitamin K production by Bacillus subtilis natto when grown in a biofilm reactor was evaluated at various concentrations of the three major nutrients, glucose, yeast extract and casein. The data was analyzed using response surface methodology (RSM).

RESULTS: The maximum concentration of MK-7 in the biofilm reactors was 20.5±0.5 mg/L, which was a 344 % increase when compared to the amount produced in suspended-cell reactors containing the same optimum media composition.

CONCLUSION: These results demonstrate the potential of utilizing biofilm reactors for MK-7 production on an industrial scale.}, } @article {pmid30471500, year = {2019}, author = {Wang, H and Hu, C and Shen, Y and Shi, B and Zhao, D and Xing, X}, title = {Response of microorganisms in biofilm to sulfadiazine and ciprofloxacin in drinking water distribution systems.}, journal = {Chemosphere}, volume = {218}, number = {}, pages = {197-204}, doi = {10.1016/j.chemosphere.2018.11.106}, pmid = {30471500}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/metabolism ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Drinking Water/*chemistry/microbiology ; Environmental Monitoring/methods ; Sulfadiazine/*pharmacology ; Water Pollutants, Chemical/pharmacology ; }, abstract = {Effects of sulfadiazine and ciprofloxacin on microorganisms in biofilm of drinking water distribution systems (DWDSs) were studied. The results verified that the increases of 16S rRNA for total bacteria and bacterial genus Hyphomicrobium were related to the promotion of antibiotic resistance genes (ARGs) and class 1 integrons (int1) in DWDSs with sulfadiazine and ciprofloxacin. Moreover, the bacteria showed higher enzymatic activities in DWDSs with sulfadiazine and ciprofloxacin, which resulted in more production of extracellular polymeric substances (EPS). The higher contents of EPS proteins and secondary structure β-sheet promoted bacterial aggregation and adsorption onto surface of pipelines to form biofilm. EPS can serve as a barrier for the microorganisms in biofilm. Therefore, the biofilm bacterial communities shifted and the 16S rRNA for total bacteria increased in DWDSs with antibiotics, which also drove the ARGs promotion. Furthermore, the two antibiotics exhibited stronger combined effects than that caused by sulfadiazine and ciprofloxacin alone.}, } @article {pmid30471310, year = {2019}, author = {Begum, JF and Tamilarasi, M and Pushpakanth, P and Balachandar, D}, title = {A simple method for direct isolation of N-acyl-L-homoserine lactone mediated biofilm-forming rhizobacteria from roots.}, journal = {Journal of microbiological methods}, volume = {156}, number = {}, pages = {34-39}, doi = {10.1016/j.mimet.2018.11.018}, pmid = {30471310}, issn = {1872-8359}, mesh = {Acyl-Butyrolactones/chemistry ; *Aeromonas/classification/isolation & purification ; Biofilms/*growth & development ; Microbiota ; Oryza/*microbiology ; Plant Roots/*microbiology ; *Pseudomonas/classification/isolation & purification ; *Quorum Sensing ; Rhizosphere ; }, abstract = {Plant-associated bacteria produce quorum sensing (QS) signals for community (biofilm) formation and functioning in the rhizosphere. The QS-positive biofilm-forming rhizobacteria that excel benefits to the plants are now gaining increased importance for agricultural use due to their high competitiveness. However, there is no method available to distinguish these bacteria from the roots of a plant to ease the isolation. Currently, all the plant-associated bacteria have to be isolated, purified and subsequently screened for the QS activity using biosensor strains. This study describes a direct isolation method for N-acyl-homoserine lactone (AHL) type quorum sensing signal producing bacteria from the plant root. In this method, the root sample collected from the field was overlaid directly with the bacterial growth medium seeded with the biosensor reporter, Chromobacterium violaceum (CV026). The AHL produced by QS positive rhizobacteria residing on the surface of the root will be recognized by violacein production of CV026. The bacterial isolates recovered from rice root using this method were further confirmed for the QS activity and biofilm formation. All the QS-positive strains produced N-butyryl DL-homoserine lactone (a C4-AHL type) signal in the culture medium and had biofilm formation during in vitro culturing. The 16S rRNA gene sequences of these QS-positive biofilm-forming rhizobacteria revealed that these strains are phylogenetically close to Pseudomonas siluiensis, Aeromonas hydrophila and A. caviae. Therefore, this could be a simple, rapid and straightforward procedure for isolation and characterization of quorum-sensing rhizobacteria from plant roots.}, } @article {pmid30469139, year = {2019}, author = {Chen, J and Wang, R and Wang, X and Chen, Z and Feng, X and Qin, M}, title = {Response of nitritation performance and microbial community structure in sequencing biofilm batch reactors filled with different zeolite and alkalinity ratio.}, journal = {Bioresource technology}, volume = {273}, number = {}, pages = {487-495}, doi = {10.1016/j.biortech.2018.11.020}, pmid = {30469139}, issn = {1873-2976}, mesh = {Adsorption ; Ammonia/metabolism ; *Biofilms ; Bioreactors/microbiology ; *Microbiota ; Nitrites/metabolism ; Nitrogen/metabolism ; Zeolites/chemistry ; }, abstract = {Ammonium (NH4[+]-N) adsorption capacity of zeolite varies from place to place, a unique attempt to use different zeolite as adsorbent media in sequencing biofilm batch reactor (SBBR) for maintaining appropriate free ammonia (FA) range to achieve partial nitritation. SBR filled with synthetic zeolite (SSBBR) and natural zeolite (NSBBR) were applied to evaluate the NH4[+]-N adsorption capacity impacts on nitrogen transformation and microbial characteristics. Significant differences in nitrite production rate (NPR) were both observed in two reactors during 4 different alkalinity ratios. The highest NPR in SSBBR and NSBBR were both obtained when the alkalinity ratio was 5:1 with the values of 1.11 and 0.90 kg N/(m[3]·d), respectively. According to Haldane model with inhibition by FA, the kinetics of the reaction were analyzed. High-throughput sequencing analysis results further presented that SSBBR had higher relative abundance average of nitrosobacteria in genus level, which was in favor of better partial nitritation.}, } @article {pmid30467753, year = {2019}, author = {Mendonça, ARV and Zanardi, GB and Brum, SS and de Campos, TA and Cardoso, CMM and Zavarize, DG}, title = {RR2 dye adsorption to Hymenaea courbaril L. bark activated carbon associated with biofilm.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {28}, pages = {28524-28532}, pmid = {30467753}, issn = {1614-7499}, mesh = {Adsorption ; Biofilms ; Brazil ; Charcoal/*analysis/chemistry ; Hymenaea ; Kinetics ; Plant Bark/*chemistry ; Water/*chemistry ; }, abstract = {This study addressed the removal performance of RR2 from aqueous solutions in adsorption columns experiments by comparing the potential of activated carbon alone (ACA) and microbially inoculated (MIAC), prepared from barks of a largely available tree in Brazilian Cerrado biome, Hymenaea courbaril L. or "Jatobá," presenting the kinetics, isotherms, breakthrough curves, and dissolved organic carbon removal. ACA presented strong interaction to RR2 dye, evidenced at the first 20 min when absorbance already attained 66.4%. The removal percentage gradually increased with time and the equilibrium occurred around 91.7% within 120 min. Langmuir model best fitted the isotherm data, indicating a maximum adsorption capacity of 4.068 mg g[-1] for the amount of 0.5 g of adsorbent. The Langmuir's model parameters KL, RL, and R[2] corresponded to 0.0234 L mg[-1], 0.4159, and 0.9663, respectively, indicating a favorable adsorption process (0 < RL < 1). The experiments in adsorption columns revealed maximum adsorption capacities of 14.38 and 11.43 mg g[-1] for MIAC and ACA, respectively, where the microbial activity favorably retarded the adsorption breakpoint in approximately 20 min and enhanced the RR2 consumption in 25.8%. Effectiveness of DOC removal attained above 90% for both ACA and MIAC, reducing the content from 86.1 to 7.84 mg L[-1] and 4.82 mg L[-1], respectively.}, } @article {pmid30466178, year = {2019}, author = {Yang, SM and Lee, DW and Park, HJ and Kwak, MH and Park, JM and Choi, MG}, title = {Hydrogen Peroxide Enhances the Antibacterial Effect of Methylene Blue-based Photodynamic Therapy on Biofilm-forming Bacteria.}, journal = {Photochemistry and photobiology}, volume = {95}, number = {3}, pages = {833-838}, doi = {10.1111/php.13056}, pmid = {30466178}, issn = {1751-1097}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; Drug Synergism ; Hydrogen Peroxide/*pharmacology ; Methylene Blue/*chemistry ; *Photochemotherapy ; Pseudomonas aeruginosa/drug effects/growth & development ; }, abstract = {Recently, increased attention has been focused on endoscopic disinfection after outbreaks of drug-resistant infections associated with gastrointestinal endoscopy. The aims of this study were to investigate the bactericidal efficacy of methylene blue (MB)-based photodynamic therapy (PDT) on Pseudomonas aeruginosa (P. aeruginosa), which is the major cause of drug-resistant postendoscopy outbreak, and to assess the synergistic effects of hydrogen peroxide addition to MB-based PDT on biofilms. In planktonic state of P. aeruginosa, the maximum decrease was 3 log10 and 5.5 log10 at 20 and 30 J cm[-2] , respectively, following MB-based PDT. However, the maximum reduction of colony forming unit (CFU) was decreased by 2.5 log10 and 3 log10 irradiation on biofilms. The biofilm formation was significantly inhibited upon irradiation with MB-based PDT. When the biofilm state of P. aeruginosa was treated with MB-based PDT with hydrogen peroxide, the CFU was significantly decreased by 6 log10 after 20 J cm[-2] , by 7 log10 after 30 J cm[-2] irradiation, suggesting significantly higher efficacy than MB-based PDT alone. The implementation of the combination of hydrogen peroxide with MB-based PDT through working channels might be appropriate for preventing early colonization and biofilm formation in the endoscope and postendoscopy outbreak.}, } @article {pmid30465645, year = {2019}, author = {Sutrina, SL and Callender, S and Grazette, T and Scantlebury, P and O'Neal, S and Thomas, K and Harris, DC and Mota-Meira, M}, title = {The quantity and distribution of biofilm growth of Escherichia coli strain ATCC 9723 depends on the carbon/energy source.}, journal = {Microbiology (Reading, England)}, volume = {165}, number = {1}, pages = {47-64}, doi = {10.1099/mic.0.000745}, pmid = {30465645}, issn = {1465-2080}, mesh = {*Biofilms ; Carbon/*metabolism ; Culture Media/metabolism ; Escherichia coli/genetics/metabolism/*physiology ; Escherichia coli Proteins/genetics/metabolism ; }, abstract = {Escherichia coli strain 15 (ATCC 9723) formed robust biofilms of two distinct forms on glass tubes. In rich, low-osmolarity medium, the biofilms were restricted to the air/liquid interface, resulting in rings attached to the glass. As it was not evident that these biofilms extended across the liquid surface, we termed them 'ring' rather than 'pellicle' biofilms. In minimal medium supplemented with a non-fermentable substrate as the carbon/energy source, we observed either robust ring biofilms or little biofilm of any type, depending on the substrate. In contrast, fermentable substrates (sugars and sugar derivatives) supported robust biofilms covering most of the solid/liquid interface, which we termed 'tube-covering biofilms'. Maximal biofilm growth was observed when the sugar was a relatively poor substrate, supporting slow growth and known to cause minimal dephosphorylation of regulatory protein Enzyme IIA[Glucose] of the phosphotransferase system. Compounds found to be inhibitors of biofilm growth, such as lactate, caused a shift from tube-covering to ring form at low concentration and complete loss of biofilm growth at high when added to minimal medium supplemented with a fermentable substrate. Exogenous cAMP activated biofilm growth under all conditions tested, leading to more intense ring or tube-covering biofilms and/or to a shift from ring to tube-covering form.}, } @article {pmid30465492, year = {2018}, author = {de Amorim, LMM and Braga, MT and Carvalho, ML and de Oliveira, IR and Querobino, SM and Alberto-Silva, C and da Rocha, JBT and Costa, MS}, title = {The Organochalcogen Compound (MeOPhSe)2 Inhibits Both Formation and the Viability of the Biofilm Produced by Candida albicans, at Different Stages of Development.}, journal = {Current pharmaceutical design}, volume = {24}, number = {33}, pages = {3964-3971}, doi = {10.2174/1381612825666181120155433}, pmid = {30465492}, issn = {1873-4286}, mesh = {Animals ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/growth & development/metabolism ; Cell Survival/drug effects ; Cells, Cultured ; Chlorocebus aethiops ; Dose-Response Relationship, Drug ; Organoselenium Compounds/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; Vero Cells ; }, abstract = {BACKGROUND: Candida albicans is a commensal and opportunistic fungus which is able to produce both local and systemic infections in immunocompromised patients. A correlation has been demonstrated between the resistance to conventional antifungal drugs and C. albicans ability to produce biofilms. Therefore, the potential of the organochalcogen compounds as antifungal therapy has been demonstrated.

METHOD: In this work, we studied the effect of the organochalcogen compound (MeOPhSe)2 on both formation and the viability of the biofilm produced by C. albicans, at different stages of development. Biofilm formation and viability were determined by a metabolic assay based on the reduction of XTT assay. In addition, the morphology of the biofilm was observed using light microscopy.

RESULTS: A significant reduction was observed in both growth and biofilm formation by C. albicans, in a dependent manner of cell density. In the presence of 2 µM (MeOPhSe)2 it was observed an inhibition of 87, 72, 69 and 56 % in C. albicans growth, using cell densities of 104, 105, 106 and 107 cells/mL, respectively. C. albicans growth was inhibited >90 % in the presence of 10 µM (MeOPhSe)2 in all cell densities used. Also, (MeOPhSe)2 was found to be able to decrease the viability of the biofilm produced by C. albicans at different stages of development. This effect was more pronounced in early biofilms as compared to mature biofilms. Biofilms forming at 6 and 12 hours was inhibited ~80% in the presence of 10 µM (MeOPhSe)2. However, mature biofilms presented an inhibition of ~40 % in the presence of 10 µM (MeOPhSe)2. The analyses of the structure of the biofilm have shown a significant reduction in the number of both yeast and filamentous form after treatment with (MeOPhSe)2. In addition, the organochalcogen compound (MeOPhSe)2 did not modify the viability of Fibroblastic cells.

CONCLUSION: Taken together, these results demonstrated the potential of the organochalcogen compound (MeOPhSe) 2 as a promising antifungal therapy.}, } @article {pmid30464758, year = {2018}, author = {Nakao, R and Myint, SL and Wai, SN and Uhlin, BE}, title = {Enhanced Biofilm Formation and Membrane Vesicle Release by Escherichia coli Expressing a Commonly Occurring Plasmid Gene, kil.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2605}, pmid = {30464758}, issn = {1664-302X}, abstract = {Escherichia coli is one of the most prevalent microorganisms forming biofilms on indwelling medical devices, as well as a representative model to study the biology and ecology of biofilms. Here, we report that a small plasmid gene, kil, enhances biofilm formation of E. coli. The kil gene is widely conserved among naturally occurring colicinogenic plasmids such as ColE1 plasmid, and is also present in some plasmid derivatives used as cloning vectors. First, we found that overexpression of the kil gene product dramatically increased biofilm mass enriched with extracellular DNA in the outer membrane-compromised strain RN102, a deep rough LPS mutant E. coli K-12 derivative. We also found that the kil-enhanced biofilm formation was further promoted by addition of physiologically relevant concentrations of Mg[2+], not only in the case of RN102, but also with the parental strain BW25113, which retains intact core-oligosaccharide LPS. Biofilm formation by kil-expressing BW25113 strain (BW25113 kil[+]) was significantly inhibited by protease but not DNase I. In addition, a large amount of proteinous materials were released from the BW25113 kil[+] cells. These materials contained soluble cytoplasmic and periplasmic proteins, and insoluble membrane vesicles (MVs). The kil-induced MVs were composed of not only outer membrane/periplasmic proteins, but also inner membrane/cytoplasmic proteins, indicating that MVs from both of the outer and inner membranes could be released into the extracellular milieu. Subcellular fractionation analysis revealed that the Kil proteins translocated to both the outer and inner membranes in whole cells of BW25113 kil[+] . Furthermore, the BW25113 kil[+] showed not only reduced viability in the stationary growth phase, but also increased susceptibility to killing by predator bacteria, Vibrio cholerae expressing the type VI secretion system, despite no obvious change in morphology and physiology of the bacterial membrane under regular culture conditions. Taken together, our findings suggest that there is risk of increasing biofilm formation and spreading of numerous MVs releasing various cellular components due to kil gene expression. From another point of view, our findings could also offer efficient MV production strategies using a conditional kil vector in biotechnological applications.}, } @article {pmid30464757, year = {2018}, author = {Al-Shabib, NA and Husain, FM and Ahmed, F and Khan, RA and Khan, MS and Ansari, FA and Alam, MZ and Ahmed, MA and Khan, MS and Baig, MH and Khan, JM and Shahzad, SA and Arshad, M and Alyousef, A and Ahmad, I}, title = {Low Temperature Synthesis of Superparamagnetic Iron Oxide (Fe3O4) Nanoparticles and Their ROS Mediated Inhibition of Biofilm Formed by Food-Associated Bacteria.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2567}, pmid = {30464757}, issn = {1664-302X}, abstract = {In the present study, a facile environmentally friendly approach was described to prepare monodisperse iron oxide (Fe3O4) nanoparticles (IONPs) by low temperature solution route. The synthesized nanoparticles were characterized using x-ray diffraction spectroscopy (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) measurements, Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric analysis (TGA) analyses. XRD patterns revealed high crystalline quality of the nanoparticles. SEM micrographs showed the monodispersed IONPs with size ranging from 6 to 9 nm. Synthesized nanoparticles demonstrated MICs of 32, 64, and 128 μg/ml against Gram negative bacteria i.e., Serratia marcescens, Escherichia coli, and Pseudomonas aeruginosa, respectively, and 32 μg/ml against Gram positive bacteria Listeria monocytogenes. IOPNs at its respective sub-MICs demonstrated significant reduction of alginate and exopolysaccharide production and subsequently demonstrated broad-spectrum inhibition of biofilm ranging from 16 to 88% in the test bacteria. Biofilm reduction was also examined using SEM and Confocal Laser Scanning Microscopy (CLSM). Interaction of IONPs with bacterial cells generated ROS contributing to reduced biofilm formation. The present study for the first time report that these IONPs were effective in obliterating pre-formed biofilms. Thus, it is envisaged that these nanoparticles with broad-spectrum biofilm inhibitory property could be exploited in the food industry as well as in medical settings to curtail biofilm based infections and losses.}, } @article {pmid30462762, year = {2018}, author = {Tonon, CC and Francisconi, RS and Bordini, EAF and Huacho, PMM and Sardi, JCO and Spolidorio, DMP}, title = {Interactions between Terpinen-4-ol and Nystatin on biofilm of Candida albicans and Candida tropicalis.}, journal = {Brazilian dental journal}, volume = {29}, number = {4}, pages = {359-367}, doi = {10.1590/0103-6440201802073}, pmid = {30462762}, issn = {1806-4760}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candida tropicalis/*drug effects ; Cell Line, Transformed ; Drug Synergism ; Microbial Sensitivity Tests ; Nystatin/*pharmacology ; Terpenes/*pharmacology ; }, abstract = {The aim of this study was to evaluate the antifungal activity of Terpinen-4-ol associated with nystatin, on single and mixed species biofilms formed by Candida albicans and Candida tropicalis, as well as the effect of terpinen-4-ol on adhesion in oral cells and the enzymatic activity. The minimum inhibitory concentrations and minimum fungicide concentrations of terpinen-4-ol and nystatin on Candida albicans and Candida tropicalis were determined using the microdilution broth method, along with their synergistic activity ("checkerboard" method). Single and mixed species biofilms were prepared using the static microtiter plate model and quantified by colony forming units (CFU/mL). The effect of Terpinen-4-ol in adhesion of Candida albicans and Candida tropicalis in coculture with oral keratinocytes (NOK Si) was evaluated, as well as the enzymatic activity by measuring the size of the precipitation zone, after the growth agar to phospholipase, protease and hemolysin. Terpinen-4-ol (4.53 mg mL-1) and nystatin (0.008 mg mL-1) were able to inhibit biofilms growth, and a synergistic antifungal effect was showed with the drug association, reducing the inhibitory concentration of nystatin up to 8 times in single biofilm of Candida albicans, and 2 times in mixed species biofilm. A small decrease in the adhesion of Candida tropicalis in NOK Si cells was showed after treatment with terpinen-4-ol, and nystatin had a greater effect for both species. For enzymatic activity, the drugs showed no action. The effect potentiated by the combination of terpinen-4-ol and nystatin and the reduction of adhesion provide evidence of its potential as an anti-fungal agent.}, } @article {pmid30461338, year = {2019}, author = {Darabpour, E and Doroodmand, MM and Halabian, R and Imani Fooladi, AA}, title = {Sulfur-Functionalized Fullerene Nanoparticle as an Inhibitor and Eliminator Agent on Pseudomonas aeruginosa Biofilm and Expression of toxA Gene.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {4}, pages = {594-602}, doi = {10.1089/mdr.2018.0008}, pmid = {30461338}, issn = {1931-8448}, mesh = {ADP Ribose Transferases/*genetics ; Anti-Bacterial Agents/*pharmacology ; Bacterial Toxins/*genetics ; Biofilms/*drug effects ; Down-Regulation/drug effects/genetics ; Exotoxins/*genetics ; Fullerenes/*pharmacology ; Microbial Sensitivity Tests/methods ; Nanoparticles/*chemistry ; Pseudomonas aeruginosa/*drug effects/genetics ; Sulfur/*pharmacology ; Virulence Factors/*genetics ; }, abstract = {Over the last decade, nanotechnology-based therapeutic platforms have been directed toward developing nanoparticles with unique properties to combat biofilms. In this study, we evaluated the antibiofilm activity of the sulfur-functionalized fullerene nanoparticles (SFF Nps) against Pseudomonas aeruginosa and also analyzed the effect of this nanoparticle on the expression of exotoxin A (toxA) gene. The functionalized fullerenes were prepared by chemical vapor deposition method. We assessed the potential of SFF Nps to inhibit biofilm formation and eradicate preformed biofilms. Also, the effect of this nanoparticle on the expression of toxA gene was investigated by real-time PCR. The minimum biofilm inhibitory concentration of SFF Nps was 1 mg/mL. The minimum biofilm-eradication concentration of SFF Nps on the young (24- and 48-hr old) and older (72- and 96-hr old) biofilms was 2 and 4 mg/mL, respectively. Field emission electron scanning microscopy images confirmed the potent ability of SFF Nps to eradicate biofilm of P. aeruginosa. The expression of toxA was downregulated in the presence of SFF Nps. In conclusion, considering the ability of SFF Nps to kill P. aeruginosa biofilm and downregulate the expression of exotoxin A, this nanoparticle can be used for treatment of both chronic and acute P. aeruginosa infections.}, } @article {pmid30460358, year = {2018}, author = {Lin, PP and Hsieh, YM and Tsai, CC}, title = {Isolation and Characterisation of Probiotics for Antagonising the Cariogenic Bacterium Streptococcus mutans and Preventing Biofilm Formation.}, journal = {Oral health & preventive dentistry}, volume = {16}, number = {5}, pages = {445-455}, doi = {10.3290/j.ohpd.a41406}, pmid = {30460358}, issn = {1602-1622}, mesh = {*Biofilms ; Coculture Techniques ; Dental Caries/*microbiology ; Feces/microbiology ; Glucosyltransferases/metabolism ; Hot Temperature ; Humans ; In Vitro Techniques ; Lactobacillus crispatus/*isolation & purification ; Lactobacillus pentosus/*isolation & purification ; *Probiotics ; Saliva/microbiology ; *Streptococcus mutans/metabolism ; }, abstract = {PURPOSE: Consumption of refined foods and beverages high in sugar make the teeth susceptible to the formation of biofilm and may lead to dental caries. The aim of the present study was to determine the ability of selected probiotics to inhibit growth and biofilm formation by the cariogenic bacterium Streptococcus mutans in vitro.

MATERIALS AND METHODS: Strains of latic acid bacteria (LAB) (n = 120) from the Bioresources Collection and Research Center (BCRC), saliva of healthy adults and infant stool were screened. The antimicrobial activity of LAB in vitro was evaluated by agar spot culture and co-culture of the S. mutans strains. Antagonistic substances in the spent culture suspensions (SCS) of LAB were precipitated by extraction with ammonium sulphate and chloroform to characterise the protein and lipophilic fractions.

RESULTS: Results of co-culturing show that the SCS of the three LAB strains (Lactobacillus pentosus 13-1, 13-4 and L. crispatus BCRC 14618) subjected to heat treatment showed statistically significantly higher antimicrobial activity. Substances produced by L. pentosus 13-4 which have the potential to exhibit antimicrobial properties might be lipophilic proteins. Additionally, microtiter plate biofilm assays indicated that in vitro biofilm formation by S. mutans is strongly modulated by L. pentosus 13-4 and L. crispatus BCRC 14618.

CONCLUSION: It can be inferred that the mechanism of reducing biofilm formation by these two LAB strains is associated with sucrose-dependent cell-cell adhesion and the gtfC level of glucosyltransferases in the biofilm. Therefore, it is suggested that L. pentosus 13-4 and L. crispatus BCRC 14618 may contribute to preventing dental caries, as they showed an inhibitory effect on the growth and biofilm formation of the cariogenic bacterium S. mutans in vitro.}, } @article {pmid30459747, year = {2018}, author = {Waack, U and Nicholson, TL}, title = {Subinhibitory Concentrations of Amoxicillin, Lincomycin, and Oxytetracycline Commonly Used to Treat Swine Increase Streptococcus suis Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2707}, pmid = {30459747}, issn = {1664-302X}, abstract = {Streptococcus suis is a bacterial swine pathogen with a significant economic burden. It typically colonizes the tonsil and nasal cavity of swine causing a variety of symptoms ranging from asymptomatic carriage to lethal systemic disease. A key barrier toward the development of improved vaccines or interventions for S. suis infections is a gap in our understanding of the mechanisms contributing to persistence in the host, in which colonized pigs continue to shed and transmit S. suis. We hypothesized that exposure to sub-MICs of antibiotics commonly used by the swine industry would increase the biofilm capacity of S. suis strains. Using a 96-well plate MIC protocol, we experimentally determined the MIC for each of 12 antibiotics for a virulent strain of S. suis strain that consistently formed biofilms using a standard crystal violet assay. Using this static biofilm assay, we demonstrated that sub-MICs of bacitracin, carbadox, chlortetracycline, enrofloxacin, gentamicin, neomycin, sulfadimethoxine, tiamulin, and tylosin did not increase S. suis biofilms. In contrast, we demonstrated that sub-MICs of amoxicillin, lincomycin, and oxytetracycline increased overall biofilm formation under both static and flow conditions. The biofilm formation of 11 additional clinical isolates were measured using the relevant concentrations of amoxicillin, lincomycin, and oxytetracycline. Eight of the eleven strains increased the biofilm formation with lincomycin, seven with amoxicillin, and three with oxytetracycline. Collectively, our data demonstrate that exposure to sub-MICs of these commonly used antibiotics contributes to increased biofilm formation of S. suis, thereby potentially increasing survival and persistence within the respiratory tract of swine.}, } @article {pmid30459738, year = {2018}, author = {Lee, JH and Kim, YG and Gupta, VK and Manoharan, RK and Lee, J}, title = {Suppression of Fluconazole Resistant Candida albicans Biofilm Formation and Filamentation by Methylindole Derivatives.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2641}, pmid = {30459738}, issn = {1664-302X}, abstract = {Candida albicans is an opportunistic fungal pathogen and most prevalent species among clinical outbreaks. It causes a range of infections, including from mild mucosal infections to serious life-threatening candidemia and disseminated candidiasis. Multiple virulence factors account for the pathogenic nature of C. albicans, and its morphological transition from budding yeast to hyphal form and subsequent biofilm formation is regarded as the most important reason for the severity of Candida infections. To address the demanding need for novel antifungals, we investigated the anti-biofilm activities of various methylindoles against C. albicans using a crystal violet assay, and the metabolic activity was assessed by using a 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide reduction assay. Changes in biofilm morphologies and thicknesses were determined by confocal laser scanning microscopy and scanning electron microscopy, respectively. Of the 21 methylindoles tested, 1-methylindole-2-carboxylic acid (1MI2CA) at 0.1 mM (17.5 μg ml[-1]) and 5-methylindole-2-carboxylic acid (5MI2CA) at 0.1 mM effectively inhibited biofilm formation by C. albicans DAY185 and ATCC10231 strains. Moreover, 1MI2CA and 5MI2CA both effectively inhibited hyphal formation, and thus, improved C. albicans infected nematode survival without inducing acute toxic effects. Furthermore, our in silico molecular modeling findings were in-line with in vitro observations. This study provides information useful for the development of novel strategies targeting candidiasis and biofilm-related infections.}, } @article {pmid30459730, year = {2018}, author = {Fish, KE and Boxall, JB}, title = {Biofilm Microbiome (Re)Growth Dynamics in Drinking Water Distribution Systems Are Impacted by Chlorine Concentration.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2519}, pmid = {30459730}, issn = {1664-302X}, abstract = {Biofilms are the dominant form of microbial loading (and organic material) within drinking water distribution systems (DWDS), yet our understanding of DWDS microbiomes is focused on the more easily accessible bulk-water. Disinfectant residuals are commonly provided to manage planktonic microbial activity in DWDS to safeguard water quality and public health, yet the impacts on the biofilm microbiome are largely unknown. We report results from a full-scale DWDS facility used to develop biofilms naturally, under one of three chlorine concentrations: Low, Medium, or High. Increasing the chlorine concentration reduced the bacterial concentration within the biofilms but quantities of fungi were unaffected. The chlorine regime was influential in shaping the community structure and composition of both taxa. There were microbial members common to all biofilms but the abundance of these varied such that at the end of the Growth phase the communities from each regime were distinct. Alpha-, Beta-, and Gamma-proteobacteria were the most abundant bacterial classes; Sordariomycetes, Leotiomycetes, and Microbotryomycetes were the most abundant classes of fungi. Mechanical cleaning was shown to immediately reduce the bacterial and fungal concentrations, followed by a lag effect on the microbiome with continued decreases in quantity and ecological indices after cleaning. However, an established community remained, which recovered such that the microbial compositions at the end of the Re-growth and initial Growth phases were similar. Interestingly, the High-chlorine biofilms showed a significant elevation in bacterial concentrations at the end of the Re-growth (after cleaning) compared the initial Growth, unlike the other regimes. This suggests adaptation to a form a resilient biofilm with potentially equal or greater risks to water quality as the other regimes. Overall, this study provides critical insights into the interaction between chlorine and the microbiome of DWDS biofilms representative of real networks, implications are made for the operation and maintenance of DWDS disinfectant and cleaning strategies.}, } @article {pmid30459455, year = {2019}, author = {Ch'ng, JH and Chong, KKL and Lam, LN and Wong, JJ and Kline, KA}, title = {Author Correction: Biofilm-associated infection by enterococci.}, journal = {Nature reviews. Microbiology}, volume = {17}, number = {2}, pages = {124}, doi = {10.1038/s41579-018-0128-7}, pmid = {30459455}, issn = {1740-1534}, abstract = {In the section on initial attachment and in Figure 1 it was erroneously indicated that enterococcal surface protein (Esp) binds collagen and fibrinogen. The text and figure were changed to remove this binding interaction both online and in the pdf. The authors apologize for any confusion caused.}, } @article {pmid30458255, year = {2019}, author = {Kannan, S and Sathasivam, G and Marudhamuthu, M}, title = {Decrease of growth, biofilm and secreted virulence in opportunistic nosocomial Pseudomonas aeruginosa ATCC 25619 by glycyrrhetinic acid.}, journal = {Microbial pathogenesis}, volume = {126}, number = {}, pages = {332-342}, doi = {10.1016/j.micpath.2018.11.026}, pmid = {30458255}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Cross Infection/microbiology ; Glycyrrhetinic Acid/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Peptide Hydrolases/metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/cytology/*drug effects/*growth & development ; Pyocyanine/metabolism ; Virulence ; Virulence Factors ; }, abstract = {The present study elucidates the antibiofilm and antivirulent capability of glycyrrhetinic acid (GRA) against Pseudomonas aeruginosa ATCC 25619. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of GRA against P. aeruginosa were found to be 160 μg/mL and 420 μg/mL respectively. In an acclimatization resistance analysis using P. aeruginosa, no resistance towards GRA was observed during the habituation period. Adequate penetration of GRA over the biofilm matrix was proposed with the membrane penetration model assembly constructed with the preformed biofilm exhibited the prospective penetration of GRA above the mature biofilm. Furthermore, GRA resulted in the attenuation of virulence factors such as motility, biofilm formation, pyocyanin secretion, secreted proteases with its sub MIC concentrations. The antibiofilm property of GRA was assessed with the light microscopy and high content screening fluorescent imaging system, which clearly demonstrates, the thickness of P. aeruginosa biofilm was reduced to 11.33 ± 2.08 μm from 39 ± 2.51 μm. Transmission Electron Microscopy (TEM) images depicted the morphological changes in cells such as disaggregation of colonies, cell disruption with loss of intracellular material, cytolytic damage, the process of morphological transformation, bacteriolysis indicating the potential effect of GRA.}, } @article {pmid30458253, year = {2019}, author = {Guo, L and Zhang, C and Chen, G and Wu, M and Liu, W and Ding, C and Dong, Q and Fan, E and Liu, Q}, title = {Reactive oxygen species inhibit biofilm formation of Listeria monocytogenes.}, journal = {Microbial pathogenesis}, volume = {127}, number = {}, pages = {183-189}, doi = {10.1016/j.micpath.2018.11.023}, pmid = {30458253}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Listeria monocytogenes/*drug effects/*growth & development ; Oxidation-Reduction ; Reactive Oxygen Species/*pharmacology ; }, abstract = {Although the level of reactive oxygen species (ROS) is altered upon the formation of bacterial biofilm, the relationship between ROS alteration and biofilm formation is still unclear. The aim of the present study is to use Listeria monocytogenes (L. monocytogenes) as a model organism to examine whether ROS have an effect on the biofilm formation. After eliminating ROS by treatment with NAD(P)H oxidase inhibitor Diphenyleneiodonium chloride (DPI) or scavenging reagents N-acetylcysteine (NAC), the biofilm formation of L. monocytogenes was examined. Our data demonstrate that DPI and NAC induced-reduction of ROS enhances the biofilm formation in L. monocytogenes without affecting bacterial growth and activity. These data provide the evidence that ROS produced by L. monocytogenes inhibit the biofilm formation.}, } @article {pmid30458115, year = {2019}, author = {Szell, T and Dressler, FF and Goelz, H and Bluemel, B and Miernik, A and Brandstetter, T and Scherag, F and Schoeb, DS}, title = {In Vitro Effects of a Novel Coating Agent on Bacterial Biofilm Development on Ureteral Stents.}, journal = {Journal of endourology}, volume = {33}, number = {3}, pages = {225-231}, doi = {10.1089/end.2018.0616}, pmid = {30458115}, issn = {1557-900X}, mesh = {Acrylamides/chemistry ; *Bacterial Adhesion ; Bacteriuria/microbiology ; *Biofilms ; Enterococcus faecalis ; Equipment Design ; *Escherichia coli ; Humans ; Hydrogels/chemistry ; Klebsiella pneumoniae ; *Stents ; Surface Properties ; Ureter/*microbiology ; Urinary Tract Infections/prevention & control ; }, abstract = {OBJECTIVES: Ureteral stenting is a widely used method for noninvasive urinary drainage in ureteral obstruction. However, biofilm development due to transient bacteriuria can cause severe complications such as incrustation with subsequent obstruction as well as recurrent urinary tract infection. Apart from local ailment such as dysuria, this increases both stent replacement frequency and incidence of complications. In this work, we investigated in vitro the bacterial adhesion to a surface-attached and cross-linked poly(N,N-dimethylacrylamide) (PDMAA) hydrogel network, which is known for its nonfouling and protein-repellent characteristics.

MATERIALS AND METHODS: To mimic the conditions encountered in vivo, PDMAA-coated and uncoated cyclic olefin polymer (COP) slides as well as polyurethane (PU)-coated glass slides were incubated in sterile human urine for 48 hours. Colonization was then simulated by adding known uropathogens, cultivated from clinical urine samples (such as Escherichia coli). After further incubation for 24 and 48 hours, slides were washed, and the remaining adherent bacteria were solubilized by ultrasound. CFUs were counted after plating and incubation for 48 hours of the resulting solution.

RESULTS: PDMAA reduced adherent E. coli about fivefold on coated PU glass slides as well as in PDMAA-coated COP slides. With adherent Enterococcus faecalis and Klebsiella pneumoniae there was a tendency to decreased biofilm formation, but the difference was not statistically significant.

CONCLUSIONS: PDMAA reduces surface adherence of the most common uropathogen significantly. Assessment of clinical relevance and of the effect on further uropathogens needs further experimental and clinical evaluations. German Clinical Trial Register ID: DRKS00013264 (approved WHO primary register).}, } @article {pmid30456700, year = {2019}, author = {Güneş, G and Hallaç, E and Özgan, M and Ertürk, A and Okutman Taş, D and Çokgor, E and Güven, D and Takacs, I and Erdinçler, A and Insel, G}, title = {Enhancement of nutrient removal performance of activated sludge with a novel hybrid biofilm process.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {3}, pages = {379-390}, doi = {10.1007/s00449-018-2042-9}, pmid = {30456700}, issn = {1615-7605}, support = {Project No. 39344//Research and Development Fund of Istanbul Technical University/ ; }, mesh = {*Biofilms ; *Biomass ; *Bioreactors ; Sewage/*microbiology ; Waste Disposal, Fluid/*methods ; }, abstract = {The aim of this study was to investigate the efficacy of a hybrid biofilm pilot-scale treatment plant, designed with a novel configuration by the integration of a fixed-film system, to improve nitrogen removal. The pilot-scale system was established at a wastewater treatment plant in Istanbul and operated based on stream separation following a process consisting of Bio-P and primary sedimentation units in which carbonaceous compounds were entrapped/incorporated in settled biomass. The ammonia-rich supernatant was directed to a moving bed biofilm (MBBR) nitrification tank to obtain an efficient nitrification with the reduced organic loading after the primary sedimentation. The conventional activated sludge process, for which the net specific growth rate ([Formula: see text]) was measured to be 0.26 day[-1] at 15 °C, exhibited a low nitrification capacity. However, the pilot-scale hybrid biofilm system secured nitrification performance up to 1.8 gN/m[2]/day ammonia loading, providing a competitive advantage over the conventional single sludge systems. The proposed hybrid configuration enables removal efficiencies of 80% and 85% for total nitrogen and phosphorus. It was possible to entrap organic matter by mixing 30% of return activated sludge (RAS) with raw wastewater. Simulation-based design study showed that the use of the hybrid biofilm system reduces the environmental footprint and aeration requirement of the nutrient removal by about 50% and 19%, respectively. Economic analyses highlighting the benefit of hybrid biofilm over conventional BNR system are illustrated.}, } @article {pmid30455229, year = {2019}, author = {Zimmerli, W and Sendi, P}, title = {Role of Rifampin against Staphylococcal Biofilm Infections In Vitro, in Animal Models, and in Orthopedic-Device-Related Infections.}, journal = {Antimicrobial agents and chemotherapy}, volume = {63}, number = {2}, pages = {}, pmid = {30455229}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms/*drug effects ; Prosthesis-Related Infections/drug therapy/microbiology ; Rifampin/*pharmacology/therapeutic use ; Staphylococcus aureus/drug effects/pathogenicity ; }, abstract = {Rifampin has been used as an agent in combination therapy in orthopedic device-related infections (ODRI) for almost three decades. The aim of this review is to provide data regarding the role of rifampin against biofilm infection in vitro, in animal models, and in clinical ODRI. Available data are gathered in order to present the rational use of rifampin combinations in patients with periprosthetic joint infection (PJI). The role of rifampin is well defined in patients with PJI and is indicated in those who fulfill the Infectious Diseases Society of America criteria for debridement and implant retention or one-stage exchange. It should be used with care because of the danger of rapid emergence of resistance. Potential drug interactions should be considered.}, } @article {pmid30454660, year = {2019}, author = {Ricciardelli, A and Casillo, A and Vergara, A and Balasco, N and Corsaro, MM and Tutino, ML and Parrilli, E}, title = {Environmental conditions shape the biofilm of the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125.}, journal = {Microbiological research}, volume = {218}, number = {}, pages = {66-75}, doi = {10.1016/j.micres.2018.09.010}, pmid = {30454660}, issn = {1618-0623}, mesh = {Acclimatization/*physiology ; Antarctic Regions ; Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Cellulose/metabolism ; Cold Temperature ; *Environment ; Extracellular Polymeric Substance Matrix/metabolism ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Confocal ; Pseudoalteromonas/*growth & development ; Stress, Physiological/physiology ; }, abstract = {Biofilms are the most widely distributed and successful microbial modes of life. The capacity of bacteria to colonize surfaces provides stability in the growth environment, allows the capturing of nutrients and affords protection from a range of environmental challenges and stress. Bacteria living in cold environments, like Antarctica, can be found as biofilms, even though the mechanisms of how this lifestyle is related to their environmental adaptation have been poorly investigated. In this paper, the biofilm of Pseudoalteromonas haloplanktis TAC125, one of the model organisms of cold-adapted bacteria, has been characterized in terms of biofilm typology and matrix composition. The characterization was performed on biofilms produced by the bacterium in response to different nutrient abundance and temperatures; in particular, this is the first report describing the structure of a biofilm formed at 0 °C. The results reported demonstrate that PhTAC125 produces biofilms in different amount and endowed with different physico-chemical properties, like hydrophobicity and roughness, by modulating the relative amount of the different macromolecules present in the biofilm matrix. The capability of PhTAC125 to adopt different biofilm structures in response to environment changes appears to be an interesting adaptation strategy and gives the first hints about the biofilm formation in cold environments.}, } @article {pmid30452884, year = {2019}, author = {Guttula, D and Yao, M and Baker, K and Yang, L and Goult, BT and Doyle, PS and Yan, J}, title = {Calcium-mediated Protein Folding and Stabilization of Salmonella Biofilm-associated Protein A.}, journal = {Journal of molecular biology}, volume = {431}, number = {2}, pages = {433-443}, doi = {10.1016/j.jmb.2018.11.014}, pmid = {30452884}, issn = {1089-8638}, mesh = {Bacterial Adhesion/physiology ; Bacterial Proteins/*metabolism ; Binding Sites ; Biofilms/*growth & development ; Calcium/*metabolism ; Protein Folding ; Salmonella/*metabolism ; Staphylococcal Protein A/*metabolism ; }, abstract = {Biofilm-associated proteins (BAPs) are important for early biofilm formation (adhesion) by bacteria and are also found in mature biofilms. BapA from Salmonella is a ~386-kDa surface protein, comprising 27 tandem repeats predicted to be bacterial Ig-like (BIg) domains. Such tandem repeats are conserved for BAPs across different bacterial species, but the function of these domains is not completely understood. In this work, we report the first study of the mechanical stability of the BapA protein. Using magnetic tweezers, we show that the folding of BapA BIg domains requires calcium binding and the folded domains have differential mechanical stabilities. Importantly, we identify that >100 nM concentration of calcium is needed for folding of the BIg domains, and the stability of the folded BIg domains is regulated by calcium over a wide concentration range from sub-micromolar (μM) to millimolar (mM). Only at mM calcium concentrations, as found in the extracellular environment, do the BIg domains have the saturated mechanical stability. BapA has been suggested to be involved in Salmonella invasion, and it is likely a crucial mechanical component of biofilms. Therefore, our results provide new insights into the potential roles of BapA as a structural maintenance component of Salmonella biofilm and also Salmonella invasion.}, } @article {pmid30451352, year = {2019}, author = {Siemon, T and Steinhauer, S and Christmann, M}, title = {Synthesis of (+)-Darwinolide, a Biofilm-Penetrating Anti-MRSA Agent.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {58}, number = {4}, pages = {1120-1122}, doi = {10.1002/anie.201813142}, pmid = {30451352}, issn = {1521-3773}, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects ; Diterpenes/*chemical synthesis/chemistry/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Microbial Sensitivity Tests ; Molecular Structure ; }, abstract = {Darwinolide, a recently identified marine natural product from the Antarctic sponge Dendrilla membranosa, was previously shown to exhibit promising activity against the biofilm phase of methicillin-resistant Staphylococcus aureus. Its challenging tetracyclic rearranged spongian diterpenoid structure links a trimethylcyclohexyl subunit to a seven-membered core with two fused tetrahydrofuran units. Herein, we describe the first synthesis of (+)-darwinolide, which features a convergent aldol fragment coupling, an Ireland-Claisen rearrangement, and an organocatalytic desymmetrization as the key steps. Our results provide a foundation for the development of novel antibiofilm-specific antibiotics.}, } @article {pmid30449911, year = {2018}, author = {Zea, L and Nisar, Z and Rubin, P and Cortesão, M and Luo, J and McBride, SA and Moeller, R and Klaus, D and Müller, D and Varanasi, KK and Muecklich, F and Stodieck, L}, title = {Design of a spaceflight biofilm experiment.}, journal = {Acta astronautica}, volume = {148}, number = {}, pages = {294-300}, pmid = {30449911}, issn = {0094-5765}, support = {80NSSC17K0036//Intramural NASA/United States ; }, abstract = {Biofilm growth has been observed in Soviet/Russian (Salyuts and Mir), American (Skylab), and International (ISS) Space Stations, sometimes jeopardizing key equipment like spacesuits, water recycling units, radiators, and navigation windows. Biofilm formation also increases the risk of human illnesses and therefore needs to be well understood to enable safe, long-duration, human space missions. Here, the design of a NASA-supported biofilm in space project is reported. This new project aims to characterize biofilm inside the International Space Station in a controlled fashion, assessing changes in mass, thickness, and morphology. The space-based experiment also aims at elucidating the biomechanical and transcriptomic mechanisms involved in the formation of a "column-and-canopy" biofilm architecture that has previously been observed in space. To search for potential solutions, different materials and surface topologies will be used as the substrata for microbial growth. The adhesion of bacteria to surfaces and therefore the initial biofilm formation is strongly governed by topographical surface features of about the bacterial scale. Thus, using Direct Laser-Interference Patterning, some material coupons will have surface patterns with periodicities equal, above or below the size of bacteria. Additionally, a novel lubricant-impregnated surface will be assessed for potential Earth and spaceflight anti-biofilm applications. This paper describes the current experiment design including microbial strains and substrata materials and nanotopographies being considered, constraints and limitations that arise from performing experiments in space, and the next steps needed to mature the design to be spaceflight-ready.}, } @article {pmid30448846, year = {2019}, author = {Sampaio, AA and Souza, SE and Ricomini-Filho, AP and Del Bel Cury, AA and Cavalcanti, YW and Cury, JA}, title = {Candida albicans Increases Dentine Demineralization Provoked by Streptococcus mutans Biofilm.}, journal = {Caries research}, volume = {53}, number = {3}, pages = {322-331}, doi = {10.1159/000494033}, pmid = {30448846}, issn = {1421-976X}, mesh = {Animals ; *Biofilms ; Candida albicans/*pathogenicity ; Cattle ; Dentin/*microbiology ; Humans ; In Vitro Techniques ; Streptococcus mutans/*pathogenicity ; *Tooth Demineralization ; }, abstract = {Streptococcus mutans are considered the most cariogenic bacteria, but it has been suggested that Candida albicans could increase their cariogenicity. However, the effect of this dual-species microorganisms' combination on dentine caries has not been experimentally evaluated. Biofilms of C. albicans, S. mutans and C. albicans + S. mutans (n = 12/biofilm) were grown in ultra-filtered tryptone yeast extract broth culture medium for 96 h on root dentine slabs of known surface hardness and exposed 8 times per day for 3 min to 10% sucrose. The medium was changed 2 times per day (after the 8 cariogenic challenges and after the overnight period of famine), and aliquots were analyzed to determinate the pH (indicator of biofilm acidogenicity). After 96 h, the biofilms were collected to determine the wet weight, colony-forming units, and the amounts of extracellular polysaccharides (soluble and insoluble). Dentine demineralization was assessed by surface hardness loss (% SHL). The architecture of the biofilms was analyzed by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Data were analyzed by ANOVA followed by Tukey's test (α = 0.05). The dual-species C. albicans + S. mutans biofilm provoked higher % SHL on dentine (p < 0.05) than the S. mutans and C. albicans biofilm. This was supported by the results of biofilm acidogenicity and the amounts of soluble (6.4 ± 2.14 vs. 4.0 ± 0.94 and 1.9 ± 0.97, respectively) and insoluble extracellular polysaccharides (24.9 ± 9.22 vs. 18.9 ± 5.92 and 0.7 ± 0.48, respectively) (p < 0.05). The C. albicans biofilm alone presented low cariogenicity. The images by CLSM and TEM, respectively, suggest that the C. albicans + S. mutans biofilm is more voluminous than the S. mutans biofilm, and S. mutans cells interact with C. albicans throughout polysaccharides from the biofilm matrix. These findings show that C. albicans enhances the cariogenic potential of the S. mutans biofilm, increasing dentine demineralization.}, } @article {pmid30446551, year = {2019}, author = {Rizzi, A and Roy, S and Bellenger, JP and Beauregard, PB}, title = {Iron Homeostasis in Bacillus subtilis Requires Siderophore Production and Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {3}, pages = {}, pmid = {30446551}, issn = {1098-5336}, mesh = {Bacillus subtilis/genetics/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Biological Transport ; Homeostasis ; Iron/*metabolism ; Siderophores/*biosynthesis ; }, abstract = {Iron (Fe) is the most important metal in biology. Despite its abundance, Fe is mostly present as a ferric form in soils, strongly limiting its bioavailability. To overcome the challenge of Fe acquisition, many microorganisms produce siderophores to retrieve Fe from natural sources. Another ubiquitous feature of bacteria in natural environments is biofilm formation. Previous studies showed that external Fe strongly influenced biofilm formation in several bacteria, suggesting that this microenvironment plays a mechanistic role in micronutrient acquisition for bacteria. Here, we applied a complementary set of analytical methods and deletion mutants to evaluate the role of biofilm formation, siderophore production, and their interaction in Fe homeostasis in Bacillus subtilis We observed that Fe homeostasis, i.e., active growth at a constant intracellular Fe concentration, requires both siderophore production and biofilm formation. Also, we report that in B. subtilis, both biofilm formation and siderophore production are required to achieve active Fe acquisition from the medium and to sustain normal growth. Furthermore, we provide evidence that the formation of biofilm slightly enhances the kinetics of Fe complexation by catechol siderophores and markedly improves siderophore use efficiency. These results provide new perspectives on the mechanism underlying siderophore-based acquisition of Fe in biofilm-forming bacteria.IMPORTANCE Iron acquisition is of fundamental importance for microorganisms, since this metal is generally poorly bioavailable under natural conditions. In the environment, most bacteria are found tightly packed within multicellular communities named biofilms. Here, using the soil Gram-positive bacterium Bacillus subtilis, we show that biofilm formation and the production of siderophores, i.e., small molecules specifically binding metals, are both essential to ensure Fe uptake from the medium and maintain cellular Fe homeostasis. The biofilm matrix appears to play an important role favoring the efficient usage of siderophores. Taken together, our results demonstrate a close link between biofilm formation and iron acquisition in B. subtilis, allowing a better comprehension of how bacteria can cope with metal limitation under environmental conditions.}, } @article {pmid30446137, year = {2019}, author = {Wang, Z and Bai, H and Lu, C and Hou, C and Qiu, Y and Zhang, P and Duan, J and Mu, H}, title = {Light controllable chitosan micelles with ROS generation and essential oil release for the treatment of bacterial biofilm.}, journal = {Carbohydrate polymers}, volume = {205}, number = {}, pages = {533-539}, doi = {10.1016/j.carbpol.2018.10.095}, pmid = {30446137}, issn = {1879-1344}, mesh = {Biofilms/*drug effects ; Chitosan/*analogs & derivatives/chemical synthesis/*chemistry/radiation effects ; Drug Carriers/chemical synthesis/*chemistry/radiation effects ; Drug Liberation/radiation effects ; Hydrophobic and Hydrophilic Interactions ; Light ; Listeria monocytogenes/physiology ; *Micelles ; Oils, Volatile/pharmacology ; Polymers/chemical synthesis/chemistry/radiation effects ; Reactive Oxygen Species ; Staphylococcus aureus/physiology ; Sulfides/chemical synthesis/chemistry/radiation effects ; Thymol/*pharmacology ; Tolonium Chloride/chemical synthesis/chemistry/radiation effects ; }, abstract = {Bacterial biofilms are widely associated with persistent infections and food contamination. High resistance to conventional antimicrobial agents resulted in an urgent need for novel formulation to eliminate these bacterial communities. Herein we fabricated light controllable chitosan micelles loading with thymol (T-TCP) for elimination of biofilm. Due to the exterior chitosan, T-TCP micelles easily bind to negative biofilm through electrostatic interaction and efficiently deliver the essential oil payloads. Under irradiation, T-TCP micelles generated ROS, which triggered simultaneous thymol release and also resulted in additional ROS-inducing bactericidal effects, both effectively eradicating biofilms of Listeria monocytogenes and Staphylococcus aureus. This formulation provided a platform for other water-insoluble antimicrobials and might be used as a potent and controllable solution to biofilm fighting.}, } @article {pmid30446019, year = {2019}, author = {Al Akeel, R and Mateen, A and Syed, R}, title = {An Alanine-Rich Peptide Attenuates Quorum Sensing-Regulated Virulence and Biofilm Formation in Staphylococcus aureus.}, journal = {Journal of AOAC International}, volume = {102}, number = {4}, pages = {1228-1234}, doi = {10.5740/jaoacint.18-0251}, pmid = {30446019}, issn = {1944-7922}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Down-Regulation ; Hemolysin Proteins/metabolism ; Plant Proteins/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Populus/chemistry ; Quorum Sensing/*drug effects ; Staphylococcus aureus/*drug effects/pathogenicity/physiology ; Virulence/drug effects ; Virulence Factors/*metabolism ; }, abstract = {Background: Alanine-rich proteins/peptides (ARP), with bioactivity of up to 20 amino acid residues, can be observed by the body easily during gastrointestinal digestion. Objective: Populus trichocarpa extract's capability to attenuate quorum sensing-regulated virulence and biofilm formation in Staphylococcus aureus is described. Methods: PT13, an ARP obtained from P. trichocarpa, was tested for its activity against S. aureus using the broth microdilution test; a crystal-violet biofilm assay was performed under a scanning electron microscope. The production of various virulence factors was estimated with PT13 treatment. Microarray gene expression profiling of PT13-treated S. aureus was conducted and compared with an untreated control. Exopolysaccharides (EPS) was estimated to observe the PT13 inhibition activity. Results: PT13 was antimicrobial toward S. aureus at different concentrations and showed a similar growth rate in the presence and absence of PT13 at concentrations ≤8 μg/mL. Biofilm production was interrupted even at low concentrations, and biofilm-related genes were down-regulated when exposed to PT13. The genes encoding cell adhesion and bacterial attachment protein were the major genes suppressed by PT13. In addition, hemolysins, clumping activity, and EPS production of S. aureus decreased after treatment in a concentration-dependent manner. Conclusions: A long-chain PT13 with effective actions that, even at low concentration levels, not only regulated the gene expression in the producer organism but also blocked the virulence gene expression in this Gram-positive human pathogen is described. Highlights: We identified a PT13 as a potential antivirulence agent that regulated production of bacterial virulence determinants (e.g., toxins, enzymes and biofilm), downwards and it may be a promising anti-virulence agent to be further developed as an anti-infective agent.}, } @article {pmid30442604, year = {2019}, author = {Bigelow, TA and Thomas, CL and Wu, H and Itani, KMF}, title = {Impact of High-Intensity Ultrasound on Strength of Surgical Mesh When Treating Biofilm Infections.}, journal = {IEEE transactions on ultrasonics, ferroelectrics, and frequency control}, volume = {66}, number = {1}, pages = {38-44}, pmid = {30442604}, issn = {1525-8955}, support = {R21 EB020722/EB/NIBIB NIH HHS/United States ; }, mesh = {Biofilms/*radiation effects ; Colony Count, Microbial ; Models, Biological ; Staphylococcus aureus/*radiation effects ; Surgical Mesh/*microbiology ; *Ultrasonic Therapy ; }, abstract = {The use of cavitation-based ultrasound histotripsy to treat infections on surgical mesh has shown great potential. However, any impact of the therapy on the mesh must be assessed before the therapy can be applied in the clinic. The goal of this study was to determine if the cavitation-based therapy would reduce the strength of the mesh thus compromising the functionality of the mesh. First, Staphylococcus aureus biofilms were grown on the surgical mesh samples and exposed to high-intensity ultrasound pulses. For each exposure, the effectiveness of the therapy was confirmed by counting the number of colony forming units (CFUs) on the mesh. Most of the exposed meshes had no CFUs with an average reduction of 5.4-log10 relative to the sham exposures. To quantify the impact of the exposure on mesh strength, the force required to tear the mesh and the maximum mesh expansion before damage were quantified for control, sham, and exposed mesh samples. There was no statistical difference between the exposed and sham/control mesh samples in terms of ultimate tensile strength and corresponding mesh expansion. The only statistical difference was with respect to mesh orientation relative to the applied load. The tensile strength increased by 1.36 N while the expansion was reduced by 1.33 mm between different mesh orientations.}, } @article {pmid30439530, year = {2019}, author = {Shin, NR and Choi, JS}, title = {Manual dexterity and dental biofilm accumulation in independent older adults without hand disabilities: A cross-sectional study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {25}, number = {}, pages = {74-83}, doi = {10.1016/j.pdpdt.2018.11.007}, pmid = {30439530}, issn = {1873-1597}, mesh = {Age Factors ; Aged ; Aged, 80 and over ; Biofilms/*growth & development ; Cross-Sectional Studies ; Female ; Health Status ; Humans ; Male ; *Motor Skills ; Oral Hygiene/*standards ; Republic of Korea ; Sex Factors ; Tooth/*microbiology ; Toothbrushing/*standards ; }, abstract = {BACKGROUND: This study investigated the relationship between manual dexterity and dental biofilm accumulation in independent older Koreans using Quantitative Light-Induced Fluorescence-Digital (QLF-D).

METHODS: This cross-sectional study included 44 participants recruited from senior welfare facilities in South Korea and aged ≥65 years. Participants were surveyed using face-to-face structured interviews; manual dexterity was assessed using the Box and Blocks Test. To evaluate dental biofilm accumulation, the 528 surfaces of six index teeth were imaged using QLF-D and then quantified into Simple Plaque Scores (SPS) and ΔR20 values. The t-test and one-way analysis of variance were used to analyze differences in SPS and ΔR20 according to general characteristics and manual dexterity.

RESULTS: Those who brushed their teeth ≤2 times per day had higher SPS and ΔR20 values on the lingual surface of tooth #24 than those who brushed ≥3 times per day (p < 0.05). The low manual dexterity group had higher SPS on lingual surfaces of teeth #12, #24, and #32, as well as higher ΔR20 values on the lingual surfaces of teeth #12, #24, #32, and #44 (p < 0.05) than the normal group.

CONCLUSIONS: The low manual dexterity group had more dental biofilm-particularly on the lingual surfaces of teeth-and more mature biofilm than the normal group. These findings indicate that reduced manual dexterity could be a predictor of poor oral hygiene in independent older adults without hand disabilities. Therefore, we suggest manual dexterity be assessed in advance of dental biofilm assessment and tooth brushing instruction.}, } @article {pmid30439400, year = {2019}, author = {Albano, M and Crulhas, BP and Alves, FCB and Pereira, AFM and Andrade, BFMT and Barbosa, LN and Furlanetto, A and Lyra, LPDS and Rall, VLM and Júnior, AF}, title = {Antibacterial and anti-biofilm activities of cinnamaldehyde against S. epidermidis.}, journal = {Microbial pathogenesis}, volume = {126}, number = {}, pages = {231-238}, doi = {10.1016/j.micpath.2018.11.009}, pmid = {30439400}, issn = {1096-1208}, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane Permeability/drug effects ; Linezolid/pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Staphylococcus epidermidis/*drug effects ; }, abstract = {The search for new antimicrobial drugs has been necessary due to the increased bacterial resistance to antibiotics currently in use, and natural products play an important role in this field. The aim of this study was to evaluate the in vitro effect of cinnamaldehyde on S. epidermidis strains, biofilm set-up prevention, as well as its effect on pre-established biofilms. The minimum inhibitory concentration (MIC) ranged from 300 to 500 μg/mL, and the minimum bactericidal concentration (MBC) from 400 to 600 μg/mL. The biofilm inhibitory concentration and biofilm eradication concentration values were four-fold (clinical isolate) and eight-fold (ATCC strain) greater than the concentration required to inhibit planktonic growth. Sub-inhibitory concentrations of cinnamaldehyde attenuated biofilm formation of S. epidermidis strains on polystyrene microtiter plates. The combination of cinnamaldehyde and linezolid was able to inhibit S. epidermidis with a bactericidal effect. Further investigation of the mechanism of action of cinnamaldehyde revealed its effect on the cell membrane permeability, and confocal laser scanning microscopy (CLSM) images illustrated the impact of cinnamaldehyde in the detachment and killing of existing biofilms. Thereby, our data confirmed the ability of cinnamaldehyde to reduce bacterial planktonic growth of S. epidermidis, inhibiting biofilm formation and eradicating pre-formed biofilm.}, } @article {pmid30433856, year = {2018}, author = {Uğur, S and Akçelik, N and Yüksel, FN and Taşkale Karatuğ, N and Akçelik, M}, title = {Effects of dam and seqA genes on biofilm and pellicle formation in Salmonella.}, journal = {Pathogens and global health}, volume = {112}, number = {7}, pages = {368-377}, pmid = {30433856}, issn = {2047-7732}, mesh = {Anti-Bacterial Agents ; Bacterial Outer Membrane Proteins/*genetics/physiology ; Biofilms/*growth & development ; DNA-Binding Proteins/*genetics/physiology ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Salmonella/*genetics/*growth & development ; Site-Specific DNA-Methyltransferase (Adenine-Specific)/*genetics/physiology ; }, abstract = {In this study, the effects of dam and seqA genes on the formation of pellicle and biofilm was determined using five different Salmonella serovars S. Group C1 (DMC2 encoded), S. Typhimurium (DMC4 encoded), S. Virchow (DMC11 encoded), S. Enteritidis (DMC22 encoded), and S. Montevideo (DMC89 encoded). dam and seqA mutants in Salmonella serovars were performed by the single step lambda red recombination method. The mutants obtained were examined according to the properties of biofilm on the polystyrene surfaces and the pellicle formation on the liquid medium. As a result of these investigations, it was determined that the biofilm formation properties on polystyrene surfaces decreased significantly (p < 0.05) in all tested dam and seqA mutants, while the pellicle formation properties were lost in the liquid medium. When pBAD24 vector, containing the dam and seqA genes cloned behind the inducible arabinose promoter, transduced into dam and seqA mutant strains, it was determined that the biofilm formation properties on the polystyrene surfaces reached to the natural strains' level in all mutant strains. Also, the pellicle formation ability was regained in the liquid media. All these data demonstrate that dam and seqA genes play an important role in the formation of biofilm and pellicle structures in Salmonella serovars.}, } @article {pmid30431405, year = {2018}, author = {Palmieri, V and Bugli, F and Cacaci, M and Perini, G and Maio, F and Delogu, G and Torelli, R and Conti, C and Sanguinetti, M and Spirito, M and Zanoni, R and Papi, M}, title = {Graphene oxide coatings prevent Candida albicans biofilm formation with a controlled release of curcumin-loaded nanocomposites.}, journal = {Nanomedicine (London, England)}, volume = {13}, number = {22}, pages = {2867-2879}, doi = {10.2217/nnm-2018-0183}, pmid = {30431405}, issn = {1748-6963}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biocompatible Materials/chemistry ; Biofilms/drug effects ; Candida albicans/drug effects ; Cell Survival/drug effects ; Curcumin/*pharmacology ; Delayed-Action Preparations/chemistry ; Drug Carriers/chemistry ; Drug Liberation ; Epithelial Cells ; Graphite/*chemistry ; Haplorhini ; Molecular Targeted Therapy/methods ; Nanocomposites/*chemistry ; Particle Size ; Polyethylene Glycols/chemistry ; Surface Properties ; }, abstract = {AIM: Fabrication of graphene oxide (GO)-based medical devices coatings that limit adhesion of Candida albicans, a main issue of healthcare-associated infections.

METHODS: The GO composites noncovalently functionalized with curcumin (CU), a hydrophobic molecule with active antimicrobial action, polyethylene glycol (PEG) that hinders the absorption of biomolecules or a combination of CU and PEG (GO-CU-PEG) were drop-casted on surfaces and antifungal efficacy was assessed.

RESULTS: We demonstrate that GO-CU-PEG coatings can reduce fungal adhesion, proliferation and biofilm formation. Furthermore, in an aqueous environment, surfaces release curcumin-PEG nanocomposites that have a minimum inhibitory concentration of 9.25 μg/ml against C. albicans.

CONCLUSION: Prevention of early cell adhesion and creation of a proximal environment unfavorable for growth make these GO-supported biomaterials attractive for innovative medical device manufacturing.}, } @article {pmid30430938, year = {2018}, author = {de Macêdo Andrade, AC and Rosalen, PL and Freires, IA and Scotti, L and Scotti, MT and Aquino, SG and de Castro, RD}, title = {Antifungal Activity, Mode of Action, Docking Prediction and Anti-biofilm Effects of (+)-β-pinene Enantiomers against Candida spp.}, journal = {Current topics in medicinal chemistry}, volume = {18}, number = {29}, pages = {2481-2490}, doi = {10.2174/1568026618666181115103104}, pmid = {30430938}, issn = {1873-4294}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Bicyclic Monoterpenes ; Biofilms/drug effects ; Bridged Bicyclo Compounds/chemistry/*pharmacology ; Candida/*drug effects ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Monoterpenes/chemistry/*pharmacology ; Stereoisomerism ; }, abstract = {AIMS: The objective of this study was to investigate the effectiveness of (+)-β-pinene inhibition on Candida spp. growth, aiming at elucidation of the mechanism of action; to determine fungal cell enzyme binding activity (through molecular docking simulations) and its effects on biofilm reduction.

METHODS: Candida strains (n=25) from referenced and clinical origins, either susceptible or resistant to standard clinical antifungals, were tested for determination of Minimum Inhibitory Concentration (MIC); Minimum Fungicidal Concentration (MFC); and microbial death curves upon treatment with (+)-β-pinene; the effects of (+)-β-pinene on the cell wall (sorbitol assay), membrane ergosterol binding, and effects on biofilm were evaluated by microdilution techniques. We also evaluated the interactions between (+)-β-pinene and cell wall and membrane enzymes of interest.

RESULTS: The MIC values of (+)-β-pinene ranged from <56.25 to 1800 µmol/L. The MIC of (+)-β-pinene did not increase when ergosterol was added to the medium, however it did increase in the presence of sorbitol, leading to a doubled MIC for C. tropicalis and C. krusei. The results of the molecular docking simulations indicated better interaction with delta-14-sterol reductase (-51 kcal/mol). (+)-β-pinene presents anti-biofilm activity against multiples species of Candida.

CONCLUSION: (+)-β-pinene has antifungal activity and most likely acts through interference with the cell wall; through molecular interaction with Delta-14-sterol reductase and, to a lesser extent, with the 1,3-β- glucan synthase. This molecule was also found to effectively reduce Candida biofilm adhesion.}, } @article {pmid30429505, year = {2018}, author = {Inaba, T and Hori, T and Aizawa, H and Sato, Y and Ogata, A and Habe, H}, title = {Microbiomes and chemical components of feed water and membrane-attached biofilm in reverse osmosis system to treat membrane bioreactor effluents.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {16805}, pmid = {30429505}, issn = {2045-2322}, mesh = {Bacteria/isolation & purification ; *Biofilms ; *Biofouling ; Bioreactors ; *Membranes, Artificial ; *Microbiota ; Osmosis ; *Water/chemistry ; }, abstract = {Reverse osmosis (RO) system at a stage after membrane bioreactor (MBR) is used for the wastewater treatment and reclamation. One of the most serious problems in this system is membrane fouling caused by biofilm formation. Here, microbiomes and chemical components of the feed water and membrane-attached biofilm of RO system to treat MBR effluents were investigated by non-destructive confocal reflection microscopy, excitation-emission fluorescence spectroscopy and high-throughput sequencing of 16S rRNA genes. The microscopic visualization indicated that the biofilm contained large amounts of microbial cells (0.5 ± 0.3~3.9 ± 2.3 µm[3]/µm[2]) and the extracellular polysaccharides (3.3 ± 1.7~9.4 ± 5.1 µm[3]/µm[2]) and proteins (1.0 ± 0.2~1.3 ± 0.1 µm[3]/µm[2]). The spectroscopic analysis identified the humic and/or fulvic acid-like substances and protein-like substances as the main membrane foulants. High-throughput sequencing showed that Pseudomonas spp. and other heterotrophic bacteria dominated the feed water microbiomes. Meanwhile, the biofilm microbiomes were composed of diverse bacteria, among which operational taxonomic units related to the autotrophic Hydrogenophaga pseudoflava and Blastochloris viridis were abundant, accounting for up to 22.9 ± 4.1% and 3.1 ± 0.4% of the total, respectively. These results demonstrated that the minor autotrophic bacteria in the feed water played pivotal roles in the formation of polysaccharide- and protein-rich biofilm on RO membrane, thereby causing membrane fouling of RO system.}, } @article {pmid30428566, year = {2018}, author = {Suzuki, I and Shimizu, T and Senpuku, H}, title = {Role of SCFAs for Fimbrillin-Dependent Biofilm Formation of Actinomyces oris.}, journal = {Microorganisms}, volume = {6}, number = {4}, pages = {}, pmid = {30428566}, issn = {2076-2607}, abstract = {Actinomyces oris expresses type 1 and 2 fimbriae on the cell surface. Type 2 fimbriae mediate co-aggregation and biofilm formation and are composed of the shaft fimbrillin FimA and the tip fimbrillin FimB. Short-chain fatty acids (SCFAs) are metabolic products of oral bacteria, but the effects of exogenous SCFAs on FimA-dependent biofilm formation are poorly understood. We performed two types of biofilm formation assays using A. oris MG1 or MG1.ΔfimA to observe the effects of SCFAs on FimA-dependent biofilm formation in 96-well and six-well microtiter plates and a flow cell system. SCFAs did not induce six- and 16-hour biofilm formation of A. oris MG1 and MG1.ΔfimA in saliva-coated 96-well and six-well microtiter plates in which metabolites produced during growth were not excluded. However, 6.25 mM butyric acid and 3.125 mM propionic acid induced FimA-dependent biofilm formation and cell death in a flow cell system in which metabolites produced during growth were excluded. Metabolites produced during growth may lead to disturbing effects of SCFAs on the biofilm formation. The pure effects of SCFAs on biofilm formation were induction of FimA-dependent biofilm formation, but the stress responses from dead cells may regulate its effects. Therefore, SCFA may play a key role in A. oris biofilm formation.}, } @article {pmid30427797, year = {2018}, author = {Rathnaweera, SS and Rusten, B and Korczyk, K and Helland, B and Rismyhr, E}, title = {Novel biofilm reactor for denitrification of municipal wastewater.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {78}, number = {7}, pages = {1566-1575}, doi = {10.2166/wst.2018.433}, pmid = {30427797}, issn = {0273-1223}, mesh = {Biofilms ; *Bioreactors ; *Denitrification ; Filtration ; Nitrogen/*analysis ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; Water Pollutants/*analysis ; }, abstract = {A pilot-scale CFIC[®] (continuous flow intermittent cleaning) reactor was run in anoxic conditions to study denitrification of wastewater. The CFIC process has already proven its capabilities for biological oxygen demand removal with a small footprint, less energy consumption and low cost. The present study focused on the applicability for denitrification. Both pre-denitrification (pre-DN) and post-denitrification (post-DN) were tested. A mixture of primary treated wastewater and nitrified wastewater was used for pre-DN and nitrified wastewater with ethanol as a carbon source was used for post-DN. The pre-DN process was carbon limited and removal rates of only 0.16 to 0.74 g NOx-N/m[2]-d were obtained. With post-DN and an external carbon source, 0.68 to 2.2 g NO3-Neq/m[2]-d removal rates were obtained. The carrier bed functioned as a good filter for both the larger particles coming with influent water and the bio-solids produced in the reactor. Total suspended solids removal in the reactor varied from 20% to 78% (average 45%) during post-DN testing period and 9% to 70% (average 29%) for pre-DN. The results showed that the forward flow washing improves both the DN function and filtration ability of the reactor.}, } @article {pmid30427559, year = {2019}, author = {Stabb, EV}, title = {Should they stay or should they go? Nitric oxide and the clash of regulators governing Vibrio fischeri biofilm formation.}, journal = {Molecular microbiology}, volume = {111}, number = {1}, pages = {1-5}, doi = {10.1111/mmi.14163}, pmid = {30427559}, issn = {1365-2958}, support = {1557964//Division of Integrative Organismal Systems/International ; 1716232//Division of Molecular and Cellular Biosciences/International ; }, mesh = {*Aliivibrio fischeri ; Animals ; Bacterial Proteins ; Biofilms ; Decapodiformes ; Gene Expression Regulation, Bacterial ; *Nitric Oxide ; Symbiosis ; }, abstract = {A key regulatory decision for many bacteria is the switch between biofilm formation and motile dispersal, and this dynamic is well illustrated in the light-organ symbiosis between the bioluminescent bacterium Vibrio fischeri and the Hawaiian bobtail squid. Biofilm formation mediated by the syp gene cluster helps V. fischeri transition from a dispersed planktonic lifestyle to a robust aggregate on the surface of the nascent symbiotic organ. However, the bacteria must then swim to pores and down into the deeper crypt tissues that they ultimately colonize. A number of positive and negative regulators control syp expression and biofilm formation, but until recently the environmental inputs controlling this clash between opposing regulatory mechanisms have been unclear. Thompson et al. have now shown that Syp-mediated biofilms can be repressed by a well-known host-derived molecule: nitric oxide. This regulation is accomplished by the NO sensor HnoX exerting control over the biofilm regulator HahK. The discoveries reported here by Thompson et al. cast new light on a critical early stage of symbiotic initiation in the V. fischeri-squid model symbiosis, and more broadly it adds to a growing understanding of the role(s) that NO and HnoX play in biofilm regulation by many bacteria.}, } @article {pmid30425687, year = {2018}, author = {Liu, J and Yang, L and Hou, Y and Soteyome, T and Zeng, B and Su, J and Li, L and Li, B and Chen, D and Li, Y and Wu, A and Shirtliff, ME and Harro, JM and Xu, Z and Peters, BM}, title = {Transcriptomics Study on Staphylococcus aureus Biofilm Under Low Concentration of Ampicillin.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2413}, pmid = {30425687}, issn = {1664-302X}, abstract = {Staphylococcus aureus is one of the representative foodborne pathogens which forms biofilm. Antibiotics are widely applied in livestock husbandry to maintain animal health and productivity, thus contribute to the dissemination of antimicrobial resistant livestock and human pathogens, and pose a significant public health threat. Effect of antibiotic pressure on S. aureus biofilm formation, as well as the mechanism, remains unclear. In this study, the regulatory mechanism of low concentration of ampicillin on S. aureus biofilm formation was elucidated. The viability and biomass of biofilm with and without 1/4 MIC ampicillin treatment for 8 h were determined by XTT and crystal violet straining assays, respectively. Transcriptomics analysis on ampicillin-induced and non-ampicillin-induced biofilms were performed by RNA-sequencing, differentially expressed genes identification and annotation, GO functional and KEGG pathway enrichment. The viability and biomass of ampicillin-induced biofilm showed dramatical increase compared to the non-ampicillin-induced biofilm. A total of 530 differentially expressed genes (DEGs) with 167 and 363 genes showing up- and down-regulation, respectively, were obtained. Upon GO functional enrichment, 183, 252, and 21 specific GO terms in biological process, molecular function and cellular component were identified, respectively. Eight KEGG pathways including "Microbial metabolism in diverse environments", "S. aureus infection", and "Monobactam biosynthesis" were significantly enriched. In addition, "beta-lactam resistance" pathway was also highly enriched. In ampicillin-induced biofilm, the significant up-regulation of genes encoding multidrug resistance efflux pump AbcA, penicillin binding proteins PBP1, PBP1a/2, and PBP3, and antimicrobial resistance proteins VraF, VraG, Dlt, and Aur indicated the positive response of S. aureus to ampicillin. The up-regulation of genes encoding surface proteins ClfB, IsdA, and SasG and genes (cap5B and cap5C) which promote the adhesion of S. aureus in ampicillin induced biofilm might explain the enhanced biofilm viability and biomass.}, } @article {pmid30423413, year = {2019}, author = {Lopes, LKO and Costa, DM and Tipple, AFV and Watanabe, E and Castillo, RB and Hu, H and Deva, AK and Vickery, K}, title = {Complex design of surgical instruments as barrier for cleaning effectiveness, favouring biofilm formation.}, journal = {The Journal of hospital infection}, volume = {103}, number = {1}, pages = {e53-e60}, doi = {10.1016/j.jhin.2018.11.001}, pmid = {30423413}, issn = {1532-2939}, mesh = {Adenosine Triphosphate/analysis ; *Bacterial Load ; Decontamination/*methods ; Humans ; Microscopy, Electron, Scanning ; Orthopedic Procedures/*instrumentation ; Staphylococcus aureus/*isolation & purification ; Sterilization/*methods ; Surgical Instruments/*microbiology ; }, abstract = {BACKGROUND: Inadequately reprocessed reusable surgical instruments (RSIs) may harbour infectious agents which may then be transferred to a suitable site for replication.

AIM: To determine the cumulative effect of 20 cycles of contamination, cleaning (manual or manual followed by automated) and steam sterilization on high-complex-design RSIs used for orthopaedic surgery.

METHODS: New flexible medullary reamers and depth gauges were contaminated by soaking in tryptone soya broth, containing 5% sheep blood and 10[9] cfu/mL of Staphylococcus aureus (ATCC 25923), for 5 min. To mimic a worse-case scenario, RSIs were dried 7 h and subjected to either (a) rinsing in distilled water, (b) manual cleaning or (c) manual plus automated cleaning (reference standard), and steam sterilization. The contamination, cleaning, and sterilization cycle was repeated 20 times. Adenosine triphosphate (ATP) was measured after cleaning procedures; microbial load and residual protein were measured following the 10[th] and 20[th] reprocessing, in triplicate. Scanning electron microscopy (SEM) was used to confirm soil and biofilm presence on the RSIs after the 20[th] reprocessing.

FINDINGS: Manual and manual plus automated cleaning significantly reduced the amount of ATP and protein residues for all RSIs. Viable bacteria were not detected following sterilization. However, SEM detected soil after automated cleaning, and soil, including biofilms, after manual cleaning.

CONCLUSION: Soil and/or biofilms were evident on complex-design RSIs following 20 cycles of contamination and reprocessing, even using the reference standard method of cleaning. Although the depth gauges could be disassembled, biological residues and biofilm accumulated in its lumen. The current design of these RSIs prevents removal of all biological soil and this may have an adverse effect on patient outcome.}, } @article {pmid30423355, year = {2019}, author = {He, J and Bao, Y and Li, J and Qiu, Z and Liu, Y and Zhang, X}, title = {Nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate reduce oral bacteria adherence and biofilm formation on human enamel surface.}, journal = {Journal of dentistry}, volume = {80}, number = {}, pages = {15-22}, doi = {10.1016/j.jdent.2018.11.003}, pmid = {30423355}, issn = {1879-176X}, mesh = {*Biofilms ; *Calcium Phosphates ; *Chitosan ; *Dental Enamel ; Humans ; Nanostructures ; Streptococcus mutans ; }, abstract = {OBJECTIVES: This study investigated the effect of CMC/ACP on oral bacteria adherence and biofilm formation on the enamel surface as well as the underlying mechanism to determine the anti-cariogenic potential of CMC/ACP.

METHODS: A mineral solution of CMC/ACP was characterised by transmission electron microscope. The bactericidal activity of CMC/ACP was evaluated with the plate count method. An in vitro biofilm model was established on saliva-coated enamel blocks; the effect of CMC/ACP on the adherence of Streptococcus mutans and Streptococcus gordonii to and biofilm formation on these blocks, as well as co-aggregation of Fusobacterium nucleatum was assessed by scanning electron microscopy, crystal violet staining, and confocal microscopy. Bacterial surface charge was estimated with the cytochrome c binding assay and by zeta potential measurement.

RESULTS: CMC/ACP nanocomplexes inhibited S. mutans and S. gordonii adherence to enamel blocks by 90% and 86% (P < 0.01), respectively, and biofilm formation by 45% and 44% (P < 0.01), respectively, after 24 h without bactericidal activity. CMC/ACP reduced F. nucleatum attachment to streptococcal biofilm by 75% (P < 0.01) while also altering cytochrome c binding to bacteria and reducing the zeta potential of the bacterial suspension.

CONCLUSIONS: CMC/ACP nanocomplexes inhibit cariogenic bacterial adherence, co-adhesion, and biofilm formation on the enamel surface, possibly by altering bacterial surface charge and enhancing the flocculation effect. As an agent that promotes remineralisation and has anti-cariogenic effects, CMC/ACP can be used to prevent and treat early caries and white spot lesions.}, } @article {pmid30423345, year = {2019}, author = {Qayyum, S and Sharma, D and Bisht, D and Khan, AU}, title = {Identification of factors involved in Enterococcus faecalis biofilm under quercetin stress.}, journal = {Microbial pathogenesis}, volume = {126}, number = {}, pages = {205-211}, doi = {10.1016/j.micpath.2018.11.013}, pmid = {30423345}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects ; Enterococcus faecalis/*drug effects/genetics/*metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/genetics ; Microbial Sensitivity Tests ; Protein Biosynthesis/drug effects ; Protein Folding/drug effects ; Protein Interaction Maps/drug effects ; Proteomics ; Quercetin/*pharmacology ; }, abstract = {Enterococcus faecalis is a gram positive enteric commensal bacteria or opportunistic pathogen and its infection involves biofilm formation. Quercetin, a plant origin polyphenol was found to inhibit E. faecalis biofilm. Crystal violet assay, SEM and CLSM microscopy confirmed biofilm inhibition by quercetin. Proteomics was used to elucidate the changes occurred in bacterial cell by quercetin treatment. 2D-Electrophorosis and MALDI-TOF analysis revealed that nineteen proteins were differentially expressed in quercetin treated sample. Glycolytic pathways, protein translation-elongation pathways and protein folding pathways were under differential expression after treatment. Real Time-PCR (RT-PCR) validated the proteomic data at genomic level except for the translation elongation factor G which showed opposite data to proteomics. Protein-protein interaction networks constructed using STRING 10.0 demonstrated strong connection of translation-elongation proteins with many important proteins. The results of the comparative analysis indicate that quercetin exerts its inhibitory effect by disturbing glycolytic, protein translation-elongation and protein folding pathways. This disturbs bacterial physiology and stops transition of planktonic cells to biofilm state.}, } @article {pmid30422688, year = {2018}, author = {Singh, P and Pandit, S and Beshay, M and Mokkapati, VRSS and Garnaes, J and Olsson, ME and Sultan, A and Mackevica, A and Mateiu, RV and Lütken, H and Daugaard, AE and Baun, A and Mijakovic, I}, title = {Anti-biofilm effects of gold and silver nanoparticles synthesized by the Rhodiola rosea rhizome extracts.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {46}, number = {sup3}, pages = {S886-S899}, doi = {10.1080/21691401.2018.1518909}, pmid = {30422688}, issn = {2169-141X}, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; *Gold/chemistry/pharmacology ; Metal Nanoparticles/*chemistry ; Plant Extracts/*chemistry ; Pseudomonas aeruginosa/*physiology ; Rhizome/*chemistry ; Rhodiola/*chemistry ; *Silver/chemistry/pharmacology ; }, abstract = {Bacterial biofilm represents a major problem in medicine. They colonize and damage medical devices and implants and, in many cases, foster development of multidrug-resistant microorganisms. Biofilm development starts by bacterial attachment to the surface and the production of extracellular polymeric substances (EPS). The EPS forms a structural scaffold for dividing bacterial cells. The EPS layers also play a protective role, preventing the access of antibiotics to biofilm-associated microorganisms. The aim of this work was to investigate the production nanoparticles that could be used to inhibit biofilm formation. The applied production procedure from rhizome extracts of Rhodiola rosea is simple and environmentally friendly, as it requires no additional reducing, stabilizing and capping agents. The produced nanoparticles were stable and crystalline in nature with an average diameter of 13-17 nm for gold nanoparticles (AuNPs) and 15-30 nm for silver nanoparticles (AgNPs). Inductively coupled plasma mass spectrometry analysis revealed the concentration of synthesized nanoparticles as 3.3 and 5.3 mg/ml for AuNPs and AgNPs, respectively. Fourier-transform infrared spectroscopy detected the presence of flavonoids, terpenes and phenols on the nanoparticle surface, which could be responsible for reducing the Au and Ag salts to nanoparticles and further stabilizing them. Furthermore, we explored the AgNPs for inhibition of Pseudomonas aeruginosa and Escherichia coli biofilms. AgNPs exhibited minimum inhibitory concentrations of 50 and 100 µg/ml, against P. aeruginosa and E. coli, respectively. The respective minimum bactericidal concentrations were 100 and 200 µg/ml. These results suggest that using the rhizome extracts of the medicinal plant R. rosea represents a viable route for green production of nanoparticles with anti-biofilm effects.}, } @article {pmid30421690, year = {2019}, author = {Tahir, S and Chowdhury, D and Legge, M and Hu, H and Whiteley, G and Glasbey, T and Deva, AK and Vickery, K}, title = {Transmission of Staphylococcus aureus from dry surface biofilm (DSB) via different types of gloves.}, journal = {Infection control and hospital epidemiology}, volume = {40}, number = {1}, pages = {60-64}, doi = {10.1017/ice.2018.285}, pmid = {30421690}, issn = {1559-6834}, mesh = {*Biofilms ; Colony Count, Microbial ; Detergents/pharmacology ; Disinfectants/pharmacology ; Environmental Microbiology ; Fomites/*microbiology ; Gloves, Protective/*microbiology ; Gloves, Surgical/*microbiology ; Health Personnel ; Humans ; Staphylococcus aureus/*isolation & purification ; Surface Properties ; }, abstract = {BACKGROUND: Pathogens can survive for extended periods when incorporated into biofilm on dry hospital surfaces (ie, dry-surface biofilm, DSB). Bacteria within biofilm are protected from desiccation and have increased tolerance to cleaning agents and disinfectants.

OBJECTIVE: We hypothesized that gloved hands of healthcare personnel (HCP) become contaminated with DSB bacteria and hence may transmit bacteria associated with healthcare-associated infections (HAIs).

METHOD: Staphylococcus aureus DSB was grown in vitro on coupons in a bioreactor over 12 days with periodic nutrition interspersed with long periods of dehydration. Each coupon had ~107 DSB bacterial cells. Transmission was tested with nitrile, latex, and surgical gloves by gripping DSB-covered coupons then pressing finger tips onto a sterile horse blood agar surface for up to 19 consecutive touches and counting the number of colony-forming units (CFU) transferred. Coupons were immersed in 5% neutral detergent to simulate cleaning, and the experiment was repeated.

RESULTS: Bacterial cells were readily transmitted by all 3 types of gloves commonly used by HCP. Surprisingly, sufficient S. aureus to cause infection were transferred from 1 DSB touch up to 19 consecutive touches. Also, 6 times more bacteria were transferred by nitrile and surgical gloves than to latex gloves (P <.001). Treating the DSB with 5% neutral detergent increased the transmission rate of DSB bacteria 10-fold.

CONCLUSION: Staphylococcus aureus incorporated into environmental DSB and covered by extracellular polymeric substances readily contaminates gloved hands and can be transferred to another surface. These results confirm the possibility that DSB contributes to HAI acquisition.}, } @article {pmid30420846, year = {2018}, author = {Wu, Y and Ma, Y and Xu, T and Zhang, QZ and Bai, J and Wang, J and Zhu, T and Lou, Q and Götz, F and Qu, D and Zheng, CQ and Zhao, KQ}, title = {Nicotine Enhances Staphylococcus epidermidis Biofilm Formation by Altering the Bacterial Autolysis, Extracellular DNA Releasing, and Polysaccharide Intercellular Adhesin Production.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2575}, pmid = {30420846}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis is a common bacterial colonizer of human skin and mucous membranes, yet it has emerged as an important nosocomial pathogen largely due to its ability to form biofilms. Tobacco smoke has been demonstrated as a contributor to various infection diseases by improving the biofilm formation of multiple bacterial species; however, the association between tobacco smoke and S. epidermidis biofilm is still unclear. In this study, we tested the effect of nicotine, one of the most active components of tobacco, on S. epidermidis biofilm formation, and we studied the underlying mechanisms. Our results showed that nicotine promoted the biofilm formation of S. epidermidis 1457 strain (SE1457) and enhanced its initial attachment to a polyethylene surface as well as polysaccharide intercellular adhesin (PIA) production. In addition, an increased extracellular DNA release and a higher autolysis rate of SE1457 was detected after nicotine treatment, which was consistent with the increased ratio of dead cells in nicotine-treated SE1457 biofilm observed with confocal laser-scanning microscopy. Furthermore, the effect of nicotine on several autolysis-related and biofilm-related gene knockout mutants of SE1457 was tested. It showed that in ΔsaeRS, ΔlytSR, and ΔsceD, nicotine induced increase in biofilm formation was similar to that in SE1457; but in ΔarlRS, ΔatlE, and ΔicaC, the effect was obviously impaired. Consistently, the increase of the bacterial autolysis rate in ΔarlRS and ΔatlE induced by nicotine was not as significant as that in SE1457. Meanwhile, the growth inhibition of nicotine on SE1457 was observed, and it was much less on ΔarlRS and restored by the arlRS complementation. The arlRS transcription in SE1457 was inhibited by nicotine during cultivation as indicated by a promoter reporter assay using green fluoresent protein. Taken together, our study indicates that nicotine improves S. epidermidis biofilm formation by promoting its initial attachment and intercellular accumulation; the arlRS, atlE, and ica genes mediating bacterial autolysis and PIA production play an important role in this process.}, } @article {pmid30419487, year = {2019}, author = {Zeng, Y and Nikitkova, A and Abdelsalam, H and Li, J and Xiao, J}, title = {Activity of quercetin and kaemferol against Streptococcus mutans biofilm.}, journal = {Archives of oral biology}, volume = {98}, number = {}, pages = {9-16}, pmid = {30419487}, issn = {1879-1506}, support = {K23 DE027412/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Colony Count, Microbial ; Dental Caries/drug therapy/prevention & control ; Drugs, Chinese Herbal/chemistry/pharmacology ; Kaempferols/*pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/pharmacology ; Quercetin/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {OBJECTIVE: Nidus Vespae (NV) is the honeycomb of Polistes Olivaceous, P. Japonicus Saussure, and Parapolybiavaria Fabricius. Previously, we have shown the extract and chemical fractions from NV demonstrated remarkable capacities of inhibiting the acid production of oral bacteria at sub-minimum inhibitory concentration (MIC) concentrations. In searching the most potent anti-caries compounds in NV, we further separated the NV Chl/MeOH fraction and obtained two purified compounds: quercetin and kaemferol. The objective of this study was to assess the effectiveness of quercetin and kaemferol against S. mutans biofilm formation.

METHODS: The MIC, minimum biofilm inhibition concentration (MBIC50) and minimum biofilm reduction concentration (MBRC50) against Streptococcus mutans were examined for NV-derived of quercetin and kaemferol. The effectiveness of inhibiting S. mutans biofilm formation was further examined using in vitro biofilm model.

RESULTS: Both quercetin and kaemferol compounds demonstrated anti-biofilm activities when compared to the negative control. They are capable of reducing biofilm dry-weight, total protein, viable cells measured by colony forming unit (CFU), insoluble and soluble glucans formation. The in situ culture pH was less acidic when the biofilms were treated by quercetin and kaemferol. The quercetin and kaemferol demonstrated comparable capability of S. mutans killing in biofilms, compared to chlorhexidine.

CONCLUSIONS: The results of this study showed inhibitory activity of quercetin and kaemferol against S. mutans biofilms, suggesting that quercetin and kaemferol might be considered as alternative anti-caries agents in searching novel anti-caries therapeutics.}, } @article {pmid30418277, year = {2019}, author = {Pilz, M and Staats, K and Tobudic, S and Assadian, O and Presterl, E and Windhager, R and Holinka, J}, title = {Zirconium Nitride Coating Reduced Staphylococcus epidermidis Biofilm Formation on Orthopaedic Implant Surfaces: An In Vitro Study.}, journal = {Clinical orthopaedics and related research}, volume = {477}, number = {2}, pages = {461-466}, pmid = {30418277}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Coated Materials, Biocompatible/*adverse effects ; Joint Prosthesis/*adverse effects/microbiology ; Materials Testing ; Prosthesis Design ; Prosthesis-Related Infections/microbiology/*prevention & control ; Staphylococcal Infections/microbiology/*prevention & control ; Staphylococcus epidermidis/*drug effects/growth & development ; Surface Properties ; Zirconium/*pharmacology ; }, abstract = {BACKGROUND: One of the most commonly identified pathogens responsible for orthopaedic implant infection is Staphylococcus epidermidis, which can form biofilms on surfaces. Currently, orthopaedic implants made of various surface materials are available, each with features influencing osseointegration, biocompatibility, and adherence of bacteria to the surface, which is the first step in biofilm formation. The aim of this experimental study was to investigate the effect of a high tribologic-resistant 2.5-µm zirconium nitride top coat on an antiallergic multilayer ceramic-covered cobalt-chromium-molybdenum surface on the formation of S. epidermidis biofilm compared with other commonly used smooth and rough orthopaedic implant surface materials.

QUESTIONS/PURPOSES: (1) When evaluating the surfaces of a cobalt-chromium-molybdenum (CoCrMo) alloy with a zirconium (Zr) nitride coating, a CoCrMo alloy without a coating, titanium alloy, a titanium alloy with a corundum-blasted rough surface, and stainless steel with a corundum-blasted rough surface, does a Zr coating reduce the number of colony-forming units of S. epidermidis in an in vitro setting? (2) Is there quantitatively less biofilm surface area on Zr-coated surfaces than on the other surfaces tested in this in vitro model?

METHODS: To determine bacterial adhesion, five different experimental implant surface discs were incubated separately with one of 31 different S. epidermidis strains each and subsequently sonicated. Twenty test strains were obtained from orthopaedic patients undergoing emergency hip prosthesis surgeries or revision of implant infection and 10 further strains were obtained from the skin of healthy individuals. Additionally, one reference strain, S. epidermidis DSM 3269, was tested. After serial dilutions, the number of bacteria was counted and expressed as colony-forming units (CFUs)/mL. For biofilm detection, discs were stained with 0.1% Safranin-O for 15 minutes, photographed, and analyzed with computer imaging software.

RESULTS: The lowest bacterial count was found in the CoCrMo + Zr surface disc (6.6 x 10 CFU/mL ± 4.6 x 10 SD) followed by the CoCrMo surface (1.1 x 10 CFU/mL ± 1.9 x 10 SD), the titanium surface (1.36 x 10 CFU/mL ± 1.8 x 10 SD), the rough stainless steel surface (2.65 x 10 CFU/mL ± 3.8 x 10 SD), and the rough titanium surface (2.1 x 10 CFU/mL ± 3.0 x 10 SD). The mean CFU count was lower for CoCrMo + Zr discs compared with the rough stainless steel surface (mean difference: 2.0 x 10, p = 0.021), the rough titanium alloy surface (mean difference: 1.4 x 10, p = 0.002), and the smooth titanium surface (mean difference: 7.0 x 10, p = 0.016). The results of biofilm formation quantification show that the mean covered area of the surface of the CoCrMo + Zr discs was 19% (± 16 SD), which was lower than CoCrMo surfaces (35% ± 23 SD), titanium alloy surface (46% ± 20 SD), rough titanium alloy surface (66% ± 23 SD), and rough stainless steel surface (58% ± 18 SD).

CONCLUSIONS: These results demonstrate that a multilayer, ceramic-covered, CoCrMo surface with a 2.5-µm zirconium nitride top coat showed less S. epidermidis biofilm formation compared with other surface materials used for orthopaedic implants.

CLINICAL RELEVANCE: CoCrMo with a 2.5-µm zirconium nitride top coat seems to be a promising surface modification technology able to reduce bacterial attachment on the surface of an implant and, hence, may further prevent implant infection with S. epidermidis biofilm formation.}, } @article {pmid30417874, year = {2018}, author = {Jin, X and Riedel-Kruse, IH}, title = {High-resolution Patterned Biofilm Deposition Using pDawn-Ag43.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {140}, pages = {}, pmid = {30417874}, issn = {1940-087X}, support = {R21 AI139941/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Adhesion/*physiology ; *Biofilms ; Escherichia coli/*genetics ; Optogenetics/*methods ; }, abstract = {Spatial structure and patterning play an important role in bacterial biofilms. Here we demonstrate an accessible method for culturing E. coli biofilms into arbitrary spatial patterns at high spatial resolution. The technique uses a genetically encoded optogenetic construct-pDawn-Ag43-that couples biofilm formation in E. coli to optical stimulation by blue light. We detail the process for transforming E. coli with pDawn-Ag43, preparing the required optical set-up, and the protocol for culturing patterned biofilms using pDawn-Ag43 bacteria. Using this protocol, biofilms with a spatial resolution below 25 μm can be patterned on various surfaces and environments, including enclosed chambers, without requiring microfabrication, clean-room facilities, or surface pretreatment. The technique is convenient and appropriate for use in applications that investigate the effect of biofilm structure, providing tunable control over biofilm patterning. More broadly, it also has potential applications in biomaterials, education, and bio-art.}, } @article {pmid30417215, year = {2019}, author = {Butini, ME and Gonzalez Moreno, M and Czuban, M and Koliszak, A and Tkhilaishvili, T and Trampuz, A and Di Luca, M}, title = {Real-Time Antimicrobial Susceptibility Assay of Planktonic and Biofilm Bacteria by Isothermal Microcalorimetry.}, journal = {Advances in experimental medicine and biology}, volume = {1214}, number = {}, pages = {61-77}, doi = {10.1007/5584_2018_291}, pmid = {30417215}, issn = {0065-2598}, mesh = {*Anti-Bacterial Agents/pharmacology ; *Bacteria/drug effects ; *Biofilms/drug effects ; *Calorimetry ; Microbial Sensitivity Tests ; *Plankton/drug effects/microbiology ; }, abstract = {Most antimicrobials currently used in the clinical practice are tested as growth inhibitors against free-floating microorganisms in a liquid suspension, rather than against sessile cells constituting biofilms. Hence, reliable, fast, and reproducible methods for assessing biofilm susceptibility to antimicrobials are strongly needed. Isothermal microcalorimetry (IMC) is a nondestructive sensitive technique that allows for the real-time monitoring of microbial viability in the presence or absence of antimicrobial compounds. Therefore, the efficacy of specific antimicrobials, alone or in combination, may be promptly validated supporting the development of new drugs and avoiding the administration of ineffective therapies. Furthermore, the susceptibility of both planktonic and biofilm cells to antimicrobials can be conveniently assessed without the need for elaborated staining procedures and under nontoxic working conditions. Quantitative data regarding the antimicrobial effect against different strains might be collected by monitoring the microbial cell replication, and, more importantly, a dose-dependent activity can be efficiently detected by measuring the delay and decrease in the heat flow peak of the treated samples. A limitation of IMC for anti-biofilm susceptibility test is the inability to directly quantify the non-replicating cells in the biofilm or the total biomass. However, as IMC is a nondestructive method, the samples can be also analyzed by using different techniques, acquiring more information complementary to calorimetric data. IMC finds application also for the investigation of antibiotic eluting kinetics from different biomaterials, as well as for studying bacteriophages activity against planktonic and biofilm bacteria. Thus, the wide applicability of this ultra-sensitive and automated technique provides a further advance in the field of clinical microbiology and biomedical sciences.}, } @article {pmid30414418, year = {2019}, author = {da Silva, PM and Baldry, M and Peng, P and de Oliveira Silva, JN and Soares, T and Brayner, FA and Alves, LC and Feitosa, APS and Paiva, PMG and Ingmer, H and Napoleão, TH}, title = {Punica granatum sarcotesta lectin (PgTeL) impairs growth, structure, viability, aggregation, and biofilm formation ability of Staphylococcus aureus clinical isolates.}, journal = {International journal of biological macromolecules}, volume = {123}, number = {}, pages = {600-608}, doi = {10.1016/j.ijbiomac.2018.11.030}, pmid = {30414418}, issn = {1879-0003}, mesh = {Biofilms/*drug effects/growth & development ; Cell Aggregation/drug effects ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Humans ; Lectins/*chemistry/pharmacology ; Lythraceae/*chemistry ; Staphylococcus aureus/*drug effects/pathogenicity ; }, abstract = {In this work, we evaluated the ability of Punica granatum sarcotesta lectin (PgTeL) to impair the growth and viability of the Staphylococcus aureus clinical isolates 8325-4 (non-resistant) and LAC USA300 (MRSA strain). The effects of this lectin on aggregating, hemolytic activity, biofilm-forming ability, and expression of virulence genes (hla, rnaIII, and spa) were also investigated. PgTeL showed antibacterial activity against 8325-4 and LAC USA300 strains by interfering with both the growth (MIC50 of 6.25 and 12.5 μg/mL, respectively) and survival (MBC values of 25.0 and 50.0 μg/mL, respectively). Culture growth started only at the ninth (8325-4) and tenth (LAC USA300) hour in the presence of PgTeL at MIC50, while growth was detected since the first hour in the control. The lectin caused markedly altered cell morphology in both the strains. Although, at the MIC50, PgTeL caused structural alterations, most cells were still viable, while at the MBC it promoted cell injury and death. PgTeL showed anti-aggregation effect and exhibited antibiofilm activity against both the isolates. However, the lectin did not interfere with the hemolytic activity of LAC USA300 and with the expression of hla, rnaIII, and spa genes. In conclusion, PgTeL is a lectin with multiple inhibitory effects on S. aureus clinical isolates.}, } @article {pmid30412313, year = {2019}, author = {Stenhagen, ISR and Rukke, HV and Dragland, IS and Kopperud, HM}, title = {Effect of methacrylated chitosan incorporated in experimental composite and adhesive on mechanical properties and biofilm formation.}, journal = {European journal of oral sciences}, volume = {127}, number = {1}, pages = {81-88}, doi = {10.1111/eos.12584}, pmid = {30412313}, issn = {1600-0722}, mesh = {Biofilms/*drug effects ; *Chitosan/chemistry/pharmacology ; *Composite Resins/pharmacology ; *Dentin-Bonding Agents/pharmacology ; Humans ; Materials Testing ; Methacrylates/chemistry ; *Streptococcus mutans ; }, abstract = {The lifespan of a resin-based restoration is limited, with the main reason for failure being secondary caries. Biofilm formation at the tooth-material interface is a necessary etiological agent for caries development. Dental materials with antimicrobial properties may reduce formation of biofilm and thus increase the longevity of restorations. This study aimed to investigate the effect of methacrylated chitosan (CH-MA), incorporated into the polymeric network of an experimental dental composite and adhesive, on biofilm growth of Streptococcus mutans and to assess the mechanical properties of the modified materials. The methacrylation of low-molecular-weight chitosan was achieved and biofilm studies confirmed the antibacterial effect of the modified polymer in solution. Methacrylated chitosan was incorporated into an experimental composite and adhesive, and the modified materials reduced the formation of S. mutans biofilm. The incorporation of CH-MA did not alter the bond strength of the adhesives. However, the amount of CH-MA in composite that is required to elicit an antibacterial response challenges the mechanical properties of the material. The hardness and flexural strength of the composite decreased with increasing amounts of CH-MA. However, flexural strength values still met the requirement in the ISO standard.}, } @article {pmid30411687, year = {2019}, author = {Zayed, MF and Ibrahim, SRM and Habib, EE and Hassan, MH and Ahmed, S and Rateb, HS}, title = {Design, Synthesis, Antimicrobial and Anti-biofilm Evaluation, and Molecular Docking of Newly Substituted Fluoroquinazolinones.}, journal = {Medicinal chemistry (Shariqah (United Arab Emirates))}, volume = {15}, number = {6}, pages = {659-675}, doi = {10.2174/1573406414666181109092944}, pmid = {30411687}, issn = {1875-6638}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/metabolism/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/metabolism/*pharmacology ; Aspergillus niger/drug effects ; Aspergillus oryzae/drug effects ; Bacteria/drug effects/enzymology ; Biofilms/drug effects ; Candida albicans/drug effects/enzymology ; Carbon-Nitrogen Ligases/chemistry/metabolism ; Drug Design ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Molecular Structure ; Protein Binding ; Quinazolinones/chemical synthesis/chemistry/metabolism/*pharmacology ; Structure-Activity Relationship ; Tetrahydrofolate Dehydrogenase/chemistry/metabolism ; }, abstract = {BACKGROUND: Quinazolines and quinazolinones derivatives are well known for their important range of therapeutic activities.

OBJECTIVE: The study aims to carry out the synthesis of some derivatives of substituted fluoroquinazolinones based on structure-based design and evaluation of their antibacterial, antifungal, and anti-biofilm activities.

METHODS: Compounds were chemically synthesized by conventional methods. Structures were established on the basis of spectral and elemental analyses. The antimicrobial potential was tested against various microorganisms using the agar disc-diffusion method. MIC and MBC as well as anti-biofilm activity for the highly active compounds were assessed. Moreover, the computational studies were performed using Auto dock free software package (version 4.0) to explain the predicted mode of binding.

RESULTS: All derivatives (5-8), (10a-g), and (A-H) were biologically tested and showed significant antimicrobial activity comparable to the reference compounds. Compounds 10b, 10c, and 10d had a good MIC and MBC against Gram-positive bacteria, whereas 10b and 10d showed significant MIC and MBC against Gram-negative bacteria. However, compounds E and F exhibited good MIC and MBC against fungi. Compound 10c and 8 exhibited significant anti-biofilm activity towards S. aureus and M. luteus. Molecular docking study revealed a strong binding of these derivatives with their receptor-site and detected their predicted mode of binding.

CONCLUSION: The synthesized derivatives showed promising antibacterial, antifungal, and antibiofilm activities. Modeling study explained their binding mode and showed strong binding affinity with their receptor-site. The highly active compounds 5 and 10c could be subjected to future optimization and investigation to be effective antimicrobial agents.}, } @article {pmid30411288, year = {2019}, author = {Yan, PF and Yuan, S and Wang, W and Hu, ZH and Mu, Y and Yu, HQ}, title = {Efficiency of sequential UV/H2O2 and biofilm process for the treatment of secondary effluent.}, journal = {Environmental science and pollution research international}, volume = {26}, number = {1}, pages = {577-585}, pmid = {30411288}, issn = {1614-7499}, support = {51538012//National Natural Science Foundation of China/ ; 51578205//National Natural Science Foundation of China/ ; 51728801//National Natural Science Foundation of China/ ; }, mesh = {Biodegradation, Environmental ; *Biofilms ; Drinking Water/analysis ; Hydrogen Peroxide/analysis/*chemistry ; Molecular Weight ; Organic Chemicals/analysis ; Oxidation-Reduction ; Waste Disposal, Fluid/*methods ; Wastewater/analysis ; Water Pollutants, Chemical/analysis ; Water Purification/methods ; }, abstract = {In response to the shortage of water resources, multiple processes have been applied to turn wastewater secondary effluent (SE) into potable water. However, trace organic contaminants (TOrCs) and high concentrations of organic matter contained in SE pose a significant challenge to the reclamation. In this manuscript, combined UV-based and biofilm processes were used to treat the SE spiked with ibuprofen (IBU) and clofibric acid (CA). The efficiency of these sequential treatments was characterized in terms of changes in dissolved organic carbon (DOC), absorbance at 254 nm (A254), fluorescence excitation-emission matrix (FEEM), the concentration of IBU and CA, and molecular weight of SE. Parallel factor (PARAFAC) was applied as the analysis method for FEEM of the samples and two fluorescent components were successfully identified: humic-like substances (C1) and protein-like matter (C2). Large reductions in A254, C1, C2, IBU, and CA were observed during the UV-based processes, especially with the addition of H2O2. Nearly 50% of A254, 80% of the component C1 were decreased and almost complete removal of the component C2 and TOrCs was achieved by UV/2.0 mM H2O2 after 90-min treatment. During the oxidation processes, the formation of lower molecular weight (LMW) compounds was detected, and the biodegradability of the organic matters was greatly increased. Although no significant DOC reduction was obtained in UV-based processes, an obvious further DOC reduction (30~60%) was achieved by biofilm treatment following UV-based processes, especially after UV/H2O2 treatments. In the meantime, large amounts of LMW were removed in the biofilm treatment process. This manuscript provides an effective advanced treatment of SE for the removal of DOC and TOrCs, facilitating the wastewater reclamation.}, } @article {pmid30410871, year = {2018}, author = {Husain, FM and Ahmad, I and Khan, FI and Al-Shabib, NA and Baig, MH and Hussain, A and Rehman, MT and Alajmi, MF and Lobb, KA}, title = {Seed Extract of Psoralea corylifolia and Its Constituent Bakuchiol Impairs AHL-Based Quorum Sensing and Biofilm Formation in Food- and Human-Related Pathogens.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {351}, pmid = {30410871}, issn = {2235-2988}, mesh = {Adaptation, Physiological/drug effects ; Animals ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects/growth & development ; Caenorhabditis elegans/microbiology ; Disease Models, Animal ; Drug Evaluation, Preclinical ; Gram-Negative Bacteria/*drug effects/physiology ; Gram-Negative Bacterial Infections/drug therapy/microbiology/pathology ; Phenols/administration & dosage/isolation & purification/*pharmacology ; Plant Extracts/administration & dosage/isolation & purification/*pharmacology ; Psoralea/*chemistry ; Quorum Sensing/*drug effects ; Seeds/chemistry ; Survival Analysis ; Treatment Outcome ; Virulence/drug effects ; }, abstract = {The emergence of multi-drug resistance in pathogenic bacteria in clinical settings as well as food-borne infections has become a serious health concern. The problem of drug resistance necessitates the need for alternative novel therapeutic strategies to combat this menace. One such approach is targeting the quorum-sensing (QS) controlled virulence and biofilm formation. In this study, we first screened different fractions of Psoralea corylifolia (seed) for their anti-QS property in the Chromobacterium violaceum 12472 strain. The methanol fraction was found to be the most active fraction and was selected for further bioassays. At sub-inhibitory concentrations, the P. corylifolia methanol fraction (PCMF) reduced QS-regulated virulence functions in C. violaceum CVO26 (violacein); Pseudomonas aeruginosa (elastase, protease, pyocyanin, chitinase, exopolysaccharides (EPS), and swarming motility), A. hydrophila (protease, EPS), and Serratia marcescens (prodigiosin). Biofilm formation in all the test pathogens was reduced significantly (p ≤ 0.005) in a concentration-dependent manner. The β-galactosidase assay showed that the PCMF at 1,000 μg/ml downregulated las-controlled transcription in PAO1. In vivo studies with C. elegans demonstrated increased survival of the nematodes after treatment with the PCMF. Bakuchiol, a phytoconstituent of the extract, demonstrated significant inhibition of QS-regulated violacein production in C. violaceum and impaired biofilm formation in the test pathogens. The molecular docking results suggested that bakuchiol efficiently binds to the active pockets of LasR and RhlR, and the complexes were stabilized by several hydrophobic interactions. Additionally, the molecular dynamics simulation of LasR, LasR-bakuchiol, RhlR, and RhlR-bakuchiol complexes for 50 ns revealed that the binding of bakuchiol to LasR and RhlR was fairly stable. The study highlights the anti-infective potential of the PCMF and bakuchiol instead of bactericidal or bacteriostatic action, as the extract targets QS-controlled virulence and the biofilm.}, } @article {pmid30408663, year = {2019}, author = {Liao, K and Bai, Y and Huo, Y and Jian, Z and Hu, W and Zhao, C and Qu, J}, title = {Use of convertible flow cells to simulate the impacts of anthropogenic activities on river biofilm bacterial communities.}, journal = {The Science of the total environment}, volume = {653}, number = {}, pages = {148-156}, doi = {10.1016/j.scitotenv.2018.10.363}, pmid = {30408663}, issn = {1879-1026}, mesh = {Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; *Biomass ; Microbiota/drug effects ; Pesticides/*adverse effects ; Waste Disposal, Fluid ; *Wastewater ; Water Pollutants, Chemical/*adverse effects ; }, abstract = {Bacterial attachment to surfaces and the development of biofilms are crucial processes during the self-purification of polluted rivers. Biofilm bacterial communities also are a potential indicator of the human impact on an aquatic system. Here, we used indoor reactors with 7.7cm[3] transparent convertible flow cells to observe the formation of biofilms in river water from different land-use areas (i.e., an undisturbed mountainous area, a wastewater-discharge urban area, and a pesticide-fertilizer applied agricultural area). We then compared the bacterial biomass, composition, and function among the formed biofilms and explored whether the biofilm bacterial communities formed in polluted river water (urban area) could shift to those formed in unpolluted water (mountainous area) after simulating water-body remediation. After 60d of indoor biofilm cultivation, the biofilms formed with the three types of influent were markedly different. Anthropogenic activities (e.g., wastewater discharge and pesticide-fertilizer use) facilitated biofilm bacterial production and the metabolic rate and altered the composition and metabolic patterns of the biofilm bacterial communities. After switching from an urban water to mountainous water influent in the same reactor, the biofilm bacterial communities that initially formed in the polluted discharge did not shift to that formed in unpolluted water. This result indicated that even after water remediation, the composition of the river biofilm bacterial community would not recover to a community like that observed under non-polluted conditions. Our study highlights possible issues related to current pollution-remediation routines and emphasizes the importance of sustainable anthropogenic activities within river basins.}, } @article {pmid30407731, year = {2019}, author = {Ebersole, JL and Peyyala, R and Gonzalez, OA}, title = {Biofilm-induced profiles of immune response gene expression by oral epithelial cells.}, journal = {Molecular oral microbiology}, volume = {34}, number = {1}, pages = {}, pmid = {30407731}, issn = {2041-1014}, support = {P20 GM103538/GM/NIGMS NIH HHS/United States ; P30 GM110788/GM/NIGMS NIH HHS/United States ; P30 GM103538/GM/NIGMS NIH HHS/United States ; }, mesh = {Adaptive Immunity ; *Biofilms ; CD59 Antigens/genetics/metabolism ; Chemokine CCL20/genetics/metabolism ; Down-Regulation ; Epithelial Cells/*immunology ; Extracellular Matrix Proteins/genetics/metabolism ; Fusobacterium nucleatum/metabolism ; Gene Expression/*drug effects/genetics/*immunology ; Gingiva/immunology ; Humans ; Hyaluronan Receptors/genetics/metabolism ; Immunity, Innate ; Interleukin-1alpha/genetics/metabolism ; Interleukin-1beta/genetics/metabolism ; Interleukin-8/genetics/metabolism ; Interleukins/genetics/metabolism ; Microbiota ; Mouth/microbiology ; NF-KappaB Inhibitor alpha/genetics/metabolism ; Porphyromonas gingivalis/metabolism ; RNA, Messenger/genetics/metabolism ; Streptococcus gordonii/metabolism ; Transcriptome/*genetics/*immunology ; Transforming Growth Factor beta/genetics/metabolism ; Up-Regulation ; }, abstract = {This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge. We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria. Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes. Biofilm challenged stimulated significant elevations compared to planktonic bacteria for IL32, IL8, CD44, B2M, TGFBI, NFKBIA, IL1B, CD59, IL1A, CCL20 representing the top 10 signals comprising 55% of the overall signal for the epithelial cell responses. Levels of PLAU, CD9, IFITM1, PLAUR, CD24, TNFSF10, and IL1RN were all elevated by each of the planktonic bacterial challenge vs the biofilm responses. While the biofilms up-regulated 123/579 genes (>2-fold), fewer genes were increased by the planktonic species (36 [S gordonii], 30 [F nucleatum], 44 [P gingivalis]). A wide array of immune genes were regulated by oral bacterial challenge of epithelial cells that would be linked to the local activity of innate and adaptive immune response components in the gingival tissues. Incorporating bacterial species into a structured biofilm dramatically altered the number and level of genes expressed. Additionally, a specific set of genes were significantly decreased with the multispecies biofilms suggesting that some epithelial cell biologic pathways are down-regulated when in contact with this type of pathogenic biofilm.}, } @article {pmid30406882, year = {2018}, author = {Das, T and Das, MC and Das, A and Bhowmik, S and Sandhu, P and Akhter, Y and Bhattacharjee, S and De, UC}, title = {Modulation of S. aureus and P. aeruginosa biofilm: an in vitro study with new coumarin derivatives.}, journal = {World journal of microbiology & biotechnology}, volume = {34}, number = {11}, pages = {170}, pmid = {30406882}, issn = {1573-0972}, mesh = {Adhesins, Bacterial/drug effects ; Anti-Bacterial Agents/*chemistry/pharmacology ; Bacterial Proteins/chemistry ; Binding Sites ; Biofilms/*drug effects/growth & development ; Computer Simulation ; Coumarins/*chemical synthesis/*chemistry/pharmacology ; Heterocyclic Compounds/chemistry/pharmacology ; Microbial Sensitivity Tests ; Models, Molecular ; Phenotype ; Pseudomonas aeruginosa/*drug effects/growth & development ; Staphylococcus aureus/*drug effects/growth & development ; }, abstract = {Coumarin is an important heterocyclic molecular framework of bioactive molecules against broad spectrum pathological manifestations. In the present study 18 new coumarin derivatives (CDs) were synthesized and characterized for antibiofilm activity against two model bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. It was observed that all the CDs executed significant effect in moderating activities against both planktonic and biofilm forms of these selected bacteria. Hence, to interpret the underlying probable reason of such antibiofilm effect, in-silico binding study of CDs with biofilm and motility associated proteins of these organisms were performed. All CDs have shown their propensity for occupying the native substrate binding pocket of each protein with moderate to strong binding affinities. One of the CDs such as CAMN1 showed highest binding affinity with these proteins. Interestingly, the findings of in-silico studies coincides the experimental results of antibiofilm and motility affect of CDs against both S. aureus and P. aeruginosa. Moreover, in-silico studies suggested that the antibiofilm activity of test CDs may be due to the interference of biofilm and motility associated proteins of the selected model organisms (PilT from P. aeruginosa and TarK, TarO from S. aureus). The detailed synthesis, characterization, methodology and results of biological screening along with computational studies have been reported. This study could be of greater interest in the context of the development of new anti-bacterial agent in the future.}, } @article {pmid30406460, year = {2018}, author = {Ali, SS and Kenawy, ER and Sonbol, FI and Sun, J and Al-Etewy, M and Ali, A and Huizi, L and El-Zawawy, NA}, title = {Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities.}, journal = {Pharmaceutical research}, volume = {36}, number = {1}, pages = {5}, pmid = {30406460}, issn = {1573-904X}, support = {NNSF-31772529//National Natural Science Foundation of China/ ; PAPD-4013000011//Priority of Academic Program Development/ ; Egyptian Ministry of Higher Education & Scientific Research (MHESR); Support of Excellent Students Projects (SESP)//Egyptian Ministry of Higher Education & Scientific Research (MHESR); Support of Excellent Students Projects (SESP)/ ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Anti-Inflammatory Agents/chemistry/*pharmacology ; Antioxidants/chemistry/*pharmacology ; Bacteria/drug effects ; Biocompatible Materials/chemistry/therapeutic use ; Biofilms/drug effects ; Cell Line ; Chitosan/analogs & derivatives/chemistry/*pharmacology ; Humans ; Mice ; Schiff Bases ; }, abstract = {PURPOSE: Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base.

METHODS: The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay.

RESULTS: MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent.

CONCLUSIONS: the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.}, } @article {pmid30406042, year = {2018}, author = {Bhandari, V and Chakraborty, S and Brahma, U and Sharma, P}, title = {Identification of Anti-staphylococcal and Anti-biofilm Compounds by Repurposing the Medicines for Malaria Venture Pathogen Box.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {365}, pmid = {30406042}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*isolation & purification/*pharmacology/toxicity ; Biofilms/*drug effects ; Cell Survival/drug effects ; Drug Evaluation, Preclinical ; *Drug Repositioning ; Mice ; Microbial Sensitivity Tests ; RAW 264.7 Cells/drug effects ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects ; }, abstract = {There has been an alarming increase in infections caused by antimicrobial-resistant pathogens. These infections are responsible for more than half a million deaths globally each year. Staphylococcus aureus is one of the deadliest bacterial pathogen responsible for nosocomial and community acquired infections. The open-access Pathogen Box (PBox) provides a potential platform to identify new treatment options against antibiotic-resistant bacteria by repurposing it. In this study, we have screened the PBox library comprised of ~400 compounds to identify novel anti-staphylococcal compounds. in vitro antimicrobial screening using S. aureus isolates, ATCC 29213 (methicillin-sensitive) and ATCC 700699 (methicillin-resistant) revealed 13 compounds which showed highly potent antibacterial activity against both planktonic and biofilm state. The 13 compounds were not found cytotoxic to mouse macrophage cell line, RAW264.7. Out of the 13 compounds, only MMV687251 and MMV676477 revealed structural similarity with vancomycin by comparing their atomic pair fingerprints using Tanimoto coefficient method. The structural similarities may indicate similar mode of action like vancomycin for the two compounds. Our result showed that PBox compounds offer a promising lead for the development of new anti-staphylococcal treatment options.}, } @article {pmid30405717, year = {2018}, author = {Marak, MB and Dhanashree, B}, title = {Antifungal Susceptibility and Biofilm Production of Candida spp. Isolated from Clinical Samples.}, journal = {International journal of microbiology}, volume = {2018}, number = {}, pages = {7495218}, pmid = {30405717}, issn = {1687-918X}, abstract = {OBJECTIVE: The study aims to speciate clinical Candida isolates and detect their biofilm-forming ability and antifungal resistance.

METHODS: All the Candida spp. isolated from different clinical samples like pus, urine, blood, and body fluid were included in the study. Biofilm production was tested by the microtiter plate method. Antifungal susceptibility was studied by the disk diffusion method. Patient's demographic details such as age, sex, and clinical information were collected. Presence of other risk factors such as diabetes mellitus, history of antibiotic use, and any urinary tract instrumentations was also recorded.

RESULTS: Among 90 Candida species isolated, most predominant species was found to be C. albicans (45.5%) followed by C. tropicalis (28.88%), C. krusei (20%), C. glabrata (3.33%), and C. parapsilosis (2.22%). Candida spp. were isolated from urine (43%), BAL/sputum (18.88%), high vaginal swab (8.88%), suction tips (7.77%), blood and wound swabs (6.66%), pus (3.33%), bile aspirate (2.22%), and deep tissue (1.11%). A larger number of females were affected than males, and the age group of 51 to 60 years was more susceptible to candidiasis. A higher number of C. albicans isolates produced biofilm followed by C. parapsilosis, C. tropicalis, and C. krusei. However, C. glabrata showed no biofilm production in our study. All Candida isolates were 100% sensitive to amphotericin B. Voriconazole was the next effective drug with 81.11% susceptibility. 24.44% of strains were resistant to fluconazole.

CONCLUSION: Speciation of Candida isolates, detection of ability to form the biofilm, and monitoring of antifungal susceptibility testing are necessary for appropriate treatment.}, } @article {pmid30405559, year = {2018}, author = {Li, T and Sharp, CE and Ataeian, M and Strous, M and de Beer, D}, title = {Role of Extracellular Carbonic Anhydrase in Dissolved Inorganic Carbon Uptake in Alkaliphilic Phototrophic Biofilm.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2490}, pmid = {30405559}, issn = {1664-302X}, abstract = {Alkaline Soda Lakes are extremely productive ecosystems, due to their high dissolved inorganic carbon (DIC) concentrations. Here, we studied the dynamics of the carbonate system, in particular, the role of extracellular carbonic anhydrase (eCA) of an alkaliphilic phototrophic biofilm composed of bacteria enriched from soda lake benthic mats. By using measurements with microsensors and membrane inlet mass spectrometry, combined with mathematical modeling, we show how eCA controls DIC uptake. In our experiments, the activity of eCA varied four-fold, and was controlled by the bicarbonate concentration during growth: a higher bicarbonate concentration led to lower eCA activity. Inhibition of eCA decreased both the net and the gross photosynthetic productivities of the investigated biofilms. After eCA inhibition, the efflux of carbon dioxide (CO2) from the biofilms increased two- to four-fold. This could be explained by the conversion of CO2, leaking from cyanobacterial cells, by eCA, to bicarbonate. Bicarbonate is then taken up again by the cyanobacteria. In suspensions, eCA reduced the CO2 leakage to the bulk medium from 90 to 50%. In biofilms cultivated at low bicarbonate concentration (~0.13 mM), the oxygen production was reduced by a similar ratio upon eCA inhibition. The role of eCA in intact biofilms was much less significant compared to biomass suspensions, as CO2 loss to the medium is reduced due to mass transfer resistance.}, } @article {pmid30405082, year = {2018}, author = {Chong, PP and Chin, VK and Wong, WF and Madhavan, P and Yong, VC and Looi, CY}, title = {Transcriptomic and Genomic Approaches for Unravelling Candida albicans Biofilm Formation and Drug Resistance-An Update.}, journal = {Genes}, volume = {9}, number = {11}, pages = {}, pmid = {30405082}, issn = {2073-4425}, abstract = {Candida albicans is an opportunistic fungal pathogen, which causes a plethora of superficial, as well as invasive, infections in humans. The ability of this fungus in switching from commensalism to active infection is attributed to its many virulence traits. Biofilm formation is a key process, which allows the fungus to adhere to and proliferate on medically implanted devices as well as host tissue and cause serious life-threatening infections. Biofilms are complex communities of filamentous and yeast cells surrounded by an extracellular matrix that confers an enhanced degree of resistance to antifungal drugs. Moreover, the extensive plasticity of the C. albicans genome has given this versatile fungus the added advantage of microevolution and adaptation to thrive within the unique environmental niches within the host. To combat these challenges in dealing with C. albicans infections, it is imperative that we target specifically the molecular pathways involved in biofilm formation as well as drug resistance. With the advent of the -omics era and whole genome sequencing platforms, novel pathways and genes involved in the pathogenesis of the fungus have been unraveled. Researchers have used a myriad of strategies including transcriptome analysis for C. albicans cells grown in different environments, whole genome sequencing of different strains, functional genomics approaches to identify critical regulatory genes, as well as comparative genomics analysis between C. albicans and its closely related, much less virulent relative, C. dubliniensis, in the quest to increase our understanding of the mechanisms underlying the success of C. albicans as a major fungal pathogen. This review attempts to summarize the most recent advancements in the field of biofilm and antifungal resistance research and offers suggestions for future directions in therapeutics development.}, } @article {pmid30404971, year = {2018}, author = {Grillo-Puertas, M and Delaporte-Quintana, P and Pedraza, RO and Rapisarda, VA}, title = {Intracellular Polyphosphate Levels in Gluconacetobacter diazotrophicus Affect Tolerance to Abiotic Stressors and Biofilm Formation.}, journal = {Microbes and environments}, volume = {33}, number = {4}, pages = {440-445}, pmid = {30404971}, issn = {1347-4405}, mesh = {Adaptation, Physiological/drug effects ; Biofilms/*growth & development ; Copper/metabolism ; Cytoplasm/metabolism ; Fragaria/growth & development/microbiology ; Gluconacetobacter/drug effects/growth & development/metabolism/*physiology ; Phosphates/pharmacology ; Polyphosphates/*metabolism ; Salts/metabolism ; Stress, Physiological/*physiology ; }, abstract = {Gluconacetobacter diazotrophicus is a plant growth-promoting bacterium that is used as a bioinoculant. Phosphate (Pi) modulates intracellular polyphosphate (polyP) levels in Escherichia coli, affecting cellular fitness and biofilm formation capacity. It currently remains unclear whether environmental Pi modulates polyP levels in G. diazotrophicus to enhance fitness in view of its technological applications. In high Pi media, cells accumulated polyP and degraded it, thereby improving survival, tolerance to environmental stressors, biofilm formation capacity on abiotic and biotic surfaces, and competence as a growth promoter of strawberry plants. The present results support the importance of Pi and intracellular polyP as signals involved in the survival of G. diazotrophicus.}, } @article {pmid30404183, year = {2018}, author = {Kot, B and Sytykiewicz, H and Sprawka, I}, title = {Expression of the Biofilm-Associated Genes in Methicillin-Resistant Staphylococcus aureus in Biofilm and Planktonic Conditions.}, journal = {International journal of molecular sciences}, volume = {19}, number = {11}, pages = {}, pmid = {30404183}, issn = {1422-0067}, mesh = {*Biofilms ; *Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/isolation & purification ; Plankton/*microbiology ; Staphylococcal Infections/microbiology ; }, abstract = {The role of genes that are essential for development of Staphylococcus aureus biofilm during infection is not fully known. mRNA from two methicillin-resistant S. aureus strains that formed weak and strong biofilm on polystyrene plates were isolated at five time points from cells grown in biofilm and planktonic culture. Quantitative real-time PCR analysis showed that the expression levels of investigated genes under biofilm conditions were significantly higher than under planktonic conditions. The expression levels of the gene encoding elastin binding protein (ebps) and laminin binding protein (eno) were significantly increased in biofilm at 3 h, both in strongly and weakly adhering strain. The peak expression of fib gene encoding fibrinogen binding protein was found at 6 and 8 h in the case of strongly and weakly adhering strain, respectively. The expression of icaA and icaD genes in both strains was significantly higher under biofilm conditions when comparing to planktonic cells during 12 h. The expression level of the genes encoding binding proteins and the glucosamine polymer polysaccharide intercellular adhesin (PIA) slowly decreased after 24 h. Finally, we found that the expression levels of genes encoding binding factors in weakly adhering strain were significantly lower than in strongly adhering strain.}, } @article {pmid30403745, year = {2018}, author = {Pederson, DB and Dong, Y and Blue, LB and Smith, SV and Cao, M}, title = {Water-soluble cranberry extract inhibits Vibrio cholerae biofilm formation possibly through modulating the second messenger 3', 5' - Cyclic diguanylate level.}, journal = {PloS one}, volume = {13}, number = {11}, pages = {e0207056}, pmid = {30403745}, issn = {1932-6203}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Plant Extracts/*pharmacology ; Quorum Sensing/drug effects ; Vaccinium macrocarpon/*chemistry ; Vibrio cholerae/cytology/*drug effects/metabolism/*physiology ; Water/*chemistry ; }, abstract = {Quorum sensing (QS) and nucleotide-based second messengers are vital signaling systems that regulate bacterial physiology in response to changing environments. Disrupting bacterial signal transduction is a promising direction to combat infectious diseases, and QS and the second messengers are undoubtedly potential targets. In Vibrio cholerae, both QS and the second messenger 3', 5'-cyclic diguanylate (c-di-GMP) play a central role in controlling motility, motile-to-sessile life transition, and virulence. In this study, we found that water-soluble extract from the North American cranberry could significantly inhibit V. cholerae biofilm formation during the development/maturation stage by reducing the biofilm matrix production and secretion. The anti-biofilm effect by water-soluble cranberry extract was possibly through modulating the intracellular c-di-GMP level and was independent of QS and the QS master regulator HapR. Our results suggest an opportunity to explore more functional foods to fight stubborn infections through interference with the bacterial signaling systems.}, } @article {pmid30401769, year = {2018}, author = {Chew, SC and Yam, JKH and Matysik, A and Seng, ZJ and Klebensberger, J and Givskov, M and Doyle, P and Rice, SA and Yang, L and Kjelleberg, S}, title = {Matrix Polysaccharides and SiaD Diguanylate Cyclase Alter Community Structure and Competitiveness of Pseudomonas aeruginosa during Dual-Species Biofilm Development with Staphylococcus aureus.}, journal = {mBio}, volume = {9}, number = {6}, pages = {}, pmid = {30401769}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; Cyclic GMP/metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Extracellular Matrix/metabolism ; Gene Expression Regulation ; *Microbial Interactions ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; Polysaccharides, Bacterial/*metabolism ; Pseudomonas aeruginosa/enzymology/*genetics ; Staphylococcus aureus/genetics/*metabolism ; }, abstract = {Mixed-species biofilms display a number of emergent properties, including enhanced antimicrobial tolerance and communal metabolism. These properties may depend on interspecies relationships and the structure of the biofilm. However, the contribution of specific matrix components to emergent properties of mixed-species biofilms remains poorly understood. Using a dual-species biofilm community formed by the opportunistic pathogens Pseudomonas aeruginosa and Staphylococcus aureus, we found that whilst neither Pel nor Psl polysaccharides, produced by P. aeruginosa, affect relative species abundance in mature P. aeruginosa and S. aureus biofilms, Psl production is associated with increased P. aeruginosa abundance and reduced S. aureus aggregation in the early stages of biofilm formation. Our data suggest that the competitive effect of Psl is not associated with its structural role in cross-linking the matrix and adhering to P. aeruginosa cells but is instead mediated through the activation of the diguanylate cyclase SiaD. This regulatory control was also found to be independent of the siderophore pyoverdine and Pseudomonas quinolone signal, which have previously been proposed to reduce S. aureus viability by inducing lactic acid fermentation-based growth. In contrast to the effect mediated by Psl, Pel reduced the effective crosslinking of the biofilm matrix and facilitated superdiffusivity in microcolony regions. These changes in matrix cross-linking enhance biofilm surface spreading and expansion of microcolonies in the later stages of biofilm development, improving overall dual-species biofilm growth and increasing biovolume severalfold. Thus, the biofilm matrix and regulators associated with matrix production play essential roles in mixed-species biofilm interactions.IMPORTANCE Bacteria in natural and engineered environments form biofilms that include many different species. Microorganisms rely on a number of different strategies to manage social interactions with other species and to access resources, build biofilm consortia, and optimize growth. For example, Pseudomonasaeruginosa and Staphylococcus aureus are biofilm-forming bacteria that coinfect the lungs of cystic fibrosis patients and diabetic and chronic wounds. P. aeruginosa is known to antagonize S. aureus growth. However, many of the factors responsible for mixed-species interactions and outcomes such as infections are poorly understood. Biofilm bacteria are encased in a self-produced extracellular matrix that facilitates interspecies behavior and biofilm development. In this study, we examined the poorly understood roles of the major matrix biopolymers and their regulators in mixed-species biofilm interactions and development.}, } @article {pmid30400188, year = {2018}, author = {Melo, MAS and Weir, MD and Passos, VF and Rolim, JPM and Lynch, CD and Rodrigues, LKA and Xu, HHK}, title = {Human In Situ Study of the effect of Bis(2-Methacryloyloxyethyl) Dimethylammonium Bromide Immobilized in Dental Composite on Controlling Mature Cariogenic Biofilm.}, journal = {International journal of molecular sciences}, volume = {19}, number = {11}, pages = {}, pmid = {30400188}, issn = {1422-0067}, support = {141791/2010-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Adult ; Biofilms/*drug effects/growth & development ; Bromides/chemistry/*pharmacology ; Colony Count, Microbial ; Dental Caries/*microbiology ; Dental Materials/chemistry/*pharmacology ; Female ; Humans ; Male ; Methacrylates/chemistry/*pharmacology ; Microbial Viability/drug effects ; Quaternary Ammonium Compounds/chemistry/*pharmacology ; Streptococcus mutans/drug effects ; Young Adult ; }, abstract = {Cariogenic oral biofilms cause recurrent dental caries around composite restorations, resulting in unprosperous oral health and expensive restorative treatment. Quaternary ammonium monomers that can be copolymerized with dental resin systems have been explored for the modulation of dental plaque biofilm growth over dental composite surfaces. Here, for the first time, we investigated the effect of bis(2-methacryloyloxyethyl) dimethylammonium bromide (QADM) on human overlying mature oral biofilms grown intra-orally in human participants for 7[-]14 days. Seventeen volunteers wore palatal devices containing composite specimens containing 10% by mass of QADM or a control composite without QADM. After 7 and 14 days, the adherent biofilms were collected to determine bacterial counts via colony-forming unit (CFU) counts. Biofilm viability, chronological changes, and percentage coverage were also determined through live/dead staining. QADM composites caused a significant inhibition of Streptococcus mutans biofilm formation for up to seven days. No difference in the CFU values were found for the 14-day period. Our findings suggest that: (1) QADM composites were successful in inhibiting 1[-]3-day biofilms in the oral environment in vivo; (2) QADM significantly reduced the portion of the S. mutans group; and (3) stronger antibiofilm activity is required for the control of mature long-term cariogenic biofilms. Contact-killing strategies using dental materials aimed at preventing or at least reducing high numbers of cariogenic bacteria seem to be a promising approach in patients at high risk of the recurrence of dental caries around composites.}, } @article {pmid30398942, year = {2018}, author = {}, title = {Skin Integrity and Infection Prevention Las Vegas: the science of biofilm, a multifaceted challenge to healing.}, journal = {Journal of wound care}, volume = {27}, number = {11}, pages = {756-757}, doi = {10.12968/jowc.2018.27.11.756}, pmid = {30398942}, issn = {0969-0700}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Congresses as Topic ; Debridement/*methods ; Humans ; Nevada ; Research Report ; Wound Healing/*physiology ; Wound Infection/*therapy ; }, abstract = {At the 4th International Skin Integrity and Infection Prevention conference, hosted by the Journal of Wound Care and the University of Huddersfield, in Las Vegas, one of the main themes was the control and resolution of biofilm. A series of reports will describe the key points of four sponsored symposia at the event. The first of these concentrates on the role of biofilm in chronic wounds and new therapies to aid the healing of these wounds by disrupting biofilm.}, } @article {pmid30398940, year = {2018}, author = {}, title = {Skin Integrity and Infection Prevention Las Vegas: don't bust on biofilm, bet on dHACM.}, journal = {Journal of wound care}, volume = {27}, number = {11}, pages = {764-766}, doi = {10.12968/jowc.2018.27.11.764}, pmid = {30398940}, issn = {0969-0700}, mesh = {Amnion/*chemistry ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Chorion/*chemistry ; Congresses as Topic ; Humans ; Intracellular Signaling Peptides and Proteins/*therapeutic use ; Nevada ; Research Report ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {The 4th International Skin Integrity and Infection Prevention conference, hosted by the Journal of Wound Care and the University of Huddersfield, was held earlier this year in Las Vegas. A key theme was the impact of biofilm on wound healing. In the second of our sponsored symposia reports, the manner in which delayed healing can be reversed through effective biofilm management, and the introduction of regulatory proteins found in dehydrated human amnion chorion membrane allograft were explained.}, } @article {pmid30397766, year = {2019}, author = {Gu, Y and Xu, Y and Xu, J and Yu, X and Huang, X and Liu, G and Liu, X}, title = {Identification of novel bacteriophage vB_EcoP-EG1 with lytic activity against planktonic and biofilm forms of uropathogenic Escherichia coli.}, journal = {Applied microbiology and biotechnology}, volume = {103}, number = {1}, pages = {315-326}, doi = {10.1007/s00253-018-9471-x}, pmid = {30397766}, issn = {1432-0614}, support = {81501797//National Natural Science Foundation of China/ ; BK20151558//Natural Science Foundation of Jiangsu Province/ ; }, mesh = {Bacteriolysis ; Biofilms ; Drug Resistance, Multiple, Bacterial ; Genome, Viral ; Host Specificity ; Humans ; Phage Therapy ; Phylogeny ; Plankton/virology ; Podoviridae/genetics/pathogenicity/*physiology ; Uropathogenic Escherichia coli/isolation & purification/*virology ; Viral Structural Proteins/genetics ; }, abstract = {Urinary tract infections are one of the most common infectious diseases worldwide. Uropathogenic Escherichia coli (UPEC) is a major cause of unary tract infection. Due to increasing prevalence of multidrug resistance, alternative methods to eradicate the UPECs are urgently needed. In this respect, phage therapy has been demonstrated to be a good candidate. Here, we described a novel bacteriophage named vB_EcoP-EG1, which can infect several strains of UPEC. Phage morphology and genome sequencing analysis show that vB_EcoP-EG1 belongs to the T7-like Podoviridae. vB_EcoP-EG1 possesses a genome (39,919 bp) containing 51 predicted genes and 149 bp terminal repeats. vB_EcoP-EG1 genome does not encode toxic proteins or proteins related to lysogeny. And no known virulent proteins were found in purified phage particles by mass spectrometry. vB_EcoP-EG1 appeared to be relatively specific and sensitive to clinical UPEC strains, which could infect 10 out of 21 clinical multidrug-resistant UPEC strains. In addition, vB_EcoP-EG1 suspension can eliminate biofilm formed by E. coli MG1655 and multidrug-resistant UPEC strain 390G7. Therefore, we concluded that vB_EcoP-EG1 has desirable characteristics for potential therapy, which may serve as an alternative to antibiotic therapy against urinary tract infections caused by multidrug-resistant UPEC.}, } @article {pmid30396900, year = {2019}, author = {Bartolini, M and Cogliati, S and Vileta, D and Bauman, C and Rateni, L and Leñini, C and Argañaraz, F and Francisco, M and Villalba, JM and Steil, L and Völker, U and Grau, R}, title = {Regulation of Biofilm Aging and Dispersal in Bacillus subtilis by the Alternative Sigma Factor SigB.}, journal = {Journal of bacteriology}, volume = {201}, number = {2}, pages = {}, pmid = {30396900}, issn = {1098-5530}, mesh = {Bacillus subtilis/genetics/*growth & development/metabolism ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Culture Media/chemistry ; *Gene Expression Regulation, Bacterial ; Locomotion ; Metabolism ; Sigma Factor/deficiency/*metabolism ; }, abstract = {Bacterial biofilms are important in natural settings, biotechnology, and medicine. However, regulation of biofilm development and its persistence in different niches is complex and only partially understood. One key step during the biofilm life cycle is dispersal, when motile cells abandon the mature biofilm to spread out and colonize new niches. Here, we show that in the model bacterium Bacillus subtilis the general stress transcription factor SigB is essential for halting detrimental overgrowth of mature biofilm and for triggering dispersal when nutrients become limited. Specifically, SigB-deficient biofilms were larger than wild-type biofilms but exhibited accelerated cell death, significantly greater sensitivity to different stresses, and reduced dispersal. Interestingly, the signal detected by SigB to limit biofilm growth was transduced through the RsbP-dependent metabolic arm of the SigB regulatory cascade, which in turn positively controlled expression of SinR, the master regulator of biofilm formation and cell motility. This novel SigB-SinR regulatory circuit might be important in controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.IMPORTANCE Biofilms are crucial for bacterial survival, adaptation, and dissemination in natural, industrial, and medical systems. Sessile cells embedded in the self-produced extracellular matrix of the biofilm benefit from a division of labor and are protected from environmental insults. However, as the biofilm ages, cells become stressed because of overcrowding, starvation, and accumulation of waste products. How does the sessile biofilm community sense and respond to stressful conditions? Here, we show that in Bacillus subtilis, the transcription factors SigB and SinR control whether cells remain in or leave a biofilm when metabolic conditions become unfavorable. This novel SigB-SinR regulatory circuit might be important for controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.}, } @article {pmid30396172, year = {2019}, author = {Lesouhaitier, O and Clamens, T and Rosay, T and Desriac, F and Louis, M and Rodrigues, S and Gannesen, A and Plakunov, VK and Bouffartigues, E and Tahrioui, A and Bazire, A and Dufour, A and Cornelis, P and Chevalier, S and Feuilloley, MGJ}, title = {Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence.}, journal = {Journal of innate immunity}, volume = {11}, number = {3}, pages = {227-241}, pmid = {30396172}, issn = {1662-8128}, mesh = {Biofilms/*drug effects ; Calcitonin Gene-Related Peptide/pharmacology ; Dynorphins/pharmacology ; Gram-Negative Bacteria/*drug effects/pathogenicity/physiology ; Gram-Positive Bacteria/*drug effects/pathogenicity/physiology ; Humans ; Natriuretic Peptides/pharmacology ; Neuropeptides/*pharmacology ; Peptide Hormones/*pharmacology ; Somatostatin/pharmacology ; Virulence ; }, abstract = {Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.}, } @article {pmid30396117, year = {2019}, author = {Ramalingam, V and Raja, S and Sundaramahalingam, S and Rajaram, R}, title = {Chemical fabrication of graphene oxide nanosheets attenuates biofilm formation of human clinical pathogens.}, journal = {Bioorganic chemistry}, volume = {83}, number = {}, pages = {326-335}, doi = {10.1016/j.bioorg.2018.10.052}, pmid = {30396117}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology/toxicity ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Graphite/chemical synthesis/*pharmacology/toxicity ; Nanostructures/*chemistry/toxicity ; Pseudomonas aeruginosa/drug effects ; }, abstract = {Graphene oxide (GO) has been recently attracted considerable interest for its potential applications in physical, chemical and biological properties. In the present study, the GO nanosheets were prepared by a chemical exfoliation technique using a modified Hummers method. Initially, the prepared GO nanosheets were confirmed by UV-vis spectroscopy and further characterized by FE-SEM, Edax, HR-TEM and SAED that demonstrated the formation of GO nanosheets with few layers flat sheet structure with hexagonal lattice crystalline nature. The FTIR spectra revealed the presence of various oxygen containing functional groups has been produced from graphite plane by exfoliation technique. The prepared GO nanosheets showed excellent antibiotic resistant activity against planktonic bacteria and more effective to damage the established biofilms and inhibits the biofilm formation of human clinical pathogens like E. coli and P. aeruginosa. Further, the GO nanosheets were found to be non-toxic to normal mammalian cells and there are no apparent morphological changes were observed in control and treated cells. In conclusion, GO nanosheets were effectively preventing the formation of biofilms and kills the represent bacteria that suggested the GO nanosheets could be used for the prevention and treatment of biofilm-related infections.}, } @article {pmid30396102, year = {2019}, author = {Wang, S and Qian, K and Zhu, Y and Yi, X and Zhang, G and Du, G and Tay, JH and Li, J}, title = {Reactivation and pilot-scale application of long-term storage denitrification biofilm based on flow cytometry.}, journal = {Water research}, volume = {148}, number = {}, pages = {368-377}, doi = {10.1016/j.watres.2018.10.072}, pmid = {30396102}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors ; *Denitrification ; Flow Cytometry ; Nitrates ; Nitrogen ; }, abstract = {The work provides a method on the basis of flow cytometry to evaluate the performance of denitrification biofilm during the preservation, reactivation and pilot-scale operation process. The viable cell ratio of denitrification biofilm significantly reduced and further led to the decrease of denitrification capacity after long-term preservation for 5 months. Protein component in tightly bound extracellular polymeric substances (TB-EPS) could serve to enhance microbial adhesion and promote denitrification biofilm formation. With the significant correlation of viable cell ratio and microbial characteristics, 4 °C was more appropriate for preserving denitrification biofilm and conducive to maintain the relatively high denitrification capacity. A maximum denitrification rate of 5.80 gNO3[-]-N/m[2]·d was obtained in pilot-scale anoxic-oxic (AO) process and Dechloromonas became greater prevalence in denitrification suspended carriers. Furthermore, the enrichment of Pseudomonas, Parcubacteria, Acidovorax, Aquabacterium and Unclassified_Flavobacteriaceae enhanced biofilm formation and nutrient conservation. The significantly positive correlation between viable cell ratio and the ratio of nitrate reduction to COD consumption was discovered, and the indices of Chao, ACE, Shannon and Simpson of denitrification biofilm were positively correlated with viable cell ratio, meaning that flow cytometry analysis was reasonable and suitable to evaluate the performances of denitrification biofilm.}, } @article {pmid30395927, year = {2019}, author = {Gao, T and Ding, M and Yang, CH and Fan, H and Chai, Y and Li, Y}, title = {The phosphotransferase system gene ptsH plays an important role in MnSOD production, biofilm formation, swarming motility, and root colonization in Bacillus cereus 905.}, journal = {Research in microbiology}, volume = {170}, number = {2}, pages = {86-96}, doi = {10.1016/j.resmic.2018.10.002}, pmid = {30395927}, issn = {1769-7123}, mesh = {Bacillus cereus/*enzymology/*genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Glucose/metabolism ; Oxidative Stress ; Phosphotransferases/*genetics ; Plant Roots/microbiology ; Rhizosphere ; Superoxide Dismutase/*biosynthesis ; Triticum/microbiology ; }, abstract = {The rhizosphere bacterium Bacillus cereus 905 is capable of promoting plant growth through effective colonization on plant roots. The sodA2-encoding manganese-containing superoxide dismutase (MnSOD2) is important for survival of B. cereus 905 in the wheat rhizosphere. However, the genes involved in regulating sodA2 expression and the mechanisms of rhizosphere colonization of B. cereus 905 are not well elucidated. In this study, we found that the deletion of the ptsH gene, which encodes the histidine-phosphorylatable protein (HPr), a component of the phosphotransferase system (PTS), causes a decrease of about 60% in the MnSOD2 expression. Evidences indicate that the ptsH dramatically influences resistance to oxidative stress, glucose uptake, as well as biofilm formation and swarming motility of B. cereus 905. Root colonization assay demonstrated that ΔptsH is defective in colonizing wheat roots, while complementation of the sodA2 gene could partially restore the ability in utilization of arabinose, a non-PTS sugar, and root colonization caused by the loss of the ptsH gene. In toto, based on the current findings, we propose that PtsH contributes to root colonization of B. cereus 905 through multiple indistinct mechanisms, involving PTS and uptake of PTS-sugars, up-regulation of MnSOD2 production, and promotion of biofilm formation and swarming motility.}, } @article {pmid30394455, year = {2018}, author = {Pousti, M and Zarabadi, MP and Abbaszadeh Amirdehi, M and Paquet-Mercier, F and Greener, J}, title = {Microfluidic bioanalytical flow cells for biofilm studies: a review.}, journal = {The Analyst}, volume = {144}, number = {1}, pages = {68-86}, doi = {10.1039/c8an01526k}, pmid = {30394455}, issn = {1364-5528}, mesh = {Bacteria/metabolism ; *Biofilms ; Electrochemical Techniques/methods ; *Lab-On-A-Chip Devices ; Microfluidic Analytical Techniques/instrumentation/*methods ; Microscopy/methods ; Spectrophotometry/methods ; Spectrum Analysis, Raman/methods ; }, abstract = {Bacterial biofilms are among the oldest and most prevalent multicellular life forms on Earth and are increasingly relevant in research areas related to industrial fouling, medicine and biotechnology. The main hurdles to obtaining definitive experimental results include time-varying biofilm properties, structural and chemical heterogeneity, and especially their strong sensitivity to environmental cues. Therefore, in addition to judicious choice of measurement tools, a well-designed biofilm study requires strict control over experimental conditions, more so than most chemical studies. Due to excellent control over a host of physiochemical parameters, microfluidic flow cells have become indispensable in microbiological studies. Not surprisingly, the number of lab-on-chip studies focusing on biofilms and other microbiological systems with expanded analytical capabilities has expanded rapidly in the past decade. In this paper, we comprehensively review the current state of microfluidic bioanalytical research applied to bacterial biofilms and offer a perspective on new approaches that are expected to drive continued advances in this field.}, } @article {pmid30394387, year = {2018}, author = {McCall, AD and Edgerton, M}, title = {Real-time Imaging and Quantification of Fungal Biofilm Development Using a Two-Phase Recirculating Flow System.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {140}, pages = {}, pmid = {30394387}, issn = {1940-087X}, support = {R01 DE010641/DE/NIDCR NIH HHS/United States ; R01 DE022720/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*growth & development ; Fungi/*growth & development ; Humans ; Lab-On-A-Chip Devices/*microbiology ; }, abstract = {In oropharyngeal candidiasis, members of the genus Candida must adhere to and grow on the oral mucosal surface while under the effects of salivary flow. While models for the growth under flow have been developed, many of these systems are expensive, or do not allow imaging while the cells are under flow. We have developed a novel apparatus that allows us to image the growth and development of Candida albicans cells under flow and in real-time. Here, we detail the protocol for the assembly and use of this flow apparatus, as well as the quantification of data that are generated. We are able to quantify the rates that the cells attach to and detach from the slide, as well as to determine a measure of the biomass on the slide over time. This system is both economical and versatile, working with many types of light microscopes, including inexpensive benchtop microscopes, and is capable of extended imaging times compared to other flow systems. Overall, this is a low-throughput system that can provide highly detailed real-time information on the biofilm growth of fungal species under flow.}, } @article {pmid30393563, year = {2018}, author = {Antypas, H and Choong, FX and Libberton, B and Brauner, A and Richter-Dahlfors, A}, title = {Rapid diagnostic assay for detection of cellulose in urine as biomarker for biofilm-related urinary tract infections.}, journal = {NPJ biofilms and microbiomes}, volume = {4}, number = {}, pages = {26}, pmid = {30393563}, issn = {2055-5008}, abstract = {The ability of uropathogenic Escherichia coli (UPEC) to adopt a biofilm lifestyle in the urinary tract is suggested as one cause of recurrent urinary tract infections (UTIs). A clinical role of UPEC biofilm is further supported by the presence of bacterial aggregates in urine of UTI patients. Yet, no diagnostics exist to differentiate between the planktonic and biofilm lifestyle of bacteria. Here, we developed a rapid diagnostic assay for biofilm-related UTI, based on the detection of cellulose in urine. Cellulose, a component of biofilm extracellular matrix, is detected by a luminescent-conjugated oligothiophene, which emits a conformation-dependent fluorescence spectrum when bound to a target molecule. We first defined the cellulose-specific spectral signature in the extracellular matrix of UPEC biofilm colonies, and used these settings to detect cellulose in urine. To translate this optotracing assay for clinical use, we composed a workflow that enabled rapid isolation of urine sediment and screening for the presence of UPEC-derived cellulose in <45 min. Using multivariate analysis, we analyzed spectral information obtained between 464 and 508 nm by optotracing of urine from 182 UTI patients and 8 healthy volunteers. Cellulose was detected in 14.8% of UTI urine samples. Using cellulose as a biomarker for biofilm-related UTI, our data provide direct evidence that UPEC forms biofilm in the urinary tract. Clinical implementation of this rapid, non-invasive and user-friendly optotracing diagnostic assay will potentially aid clinicians in the design of effective antibiotic treatment.}, } @article {pmid30393533, year = {2018}, author = {Perez-Soto, N and Moule, L and Crisan, DN and Insua, I and Taylor-Smith, LM and Voelz, K and Fernandez-Trillo, F and Krachler, AM}, title = {Correction: Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio cholerae and downregulate the expression of virulence genes.}, journal = {Chemical science}, volume = {9}, number = {39}, pages = {7715}, pmid = {30393533}, issn = {2041-6520}, abstract = {[This corrects the article DOI: 10.1039/C7SC00615B.].}, } @article {pmid30393211, year = {2018}, author = {Liaqat, I and Mirza, SA and Iqbal, R and Ali, NM and Saleem, G and Majid, S and Shahid, M}, title = {Flagellar motility plays important role in Biofilm formation of Bacillus cereus and Yersinia enterocolitica.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {31}, number = {5(Supplementary)}, pages = {2047-2052}, pmid = {30393211}, issn = {1011-601X}, mesh = {Bacillus cereus/isolation & purification/*physiology ; Biofilms/*growth & development ; Cell Movement/*physiology ; Flagella/*microbiology/*physiology ; Humans ; RNA, Bacterial/genetics/metabolism ; Yersinia enterocolitica/isolation & purification/*physiology ; }, abstract = {Bacteria live either independently as planktonic cells or in organized surface associated colonies called as biofilms. Biofilms play an important role in increased pathogenesis of bacteria and it is assumed that motility is one of the contributing factors towards biofilm initiation. This study was planned to identify the role of flagella in biofilm formation by constructing flagellated (wild type) and physically disrupted variants (non-motile). Total 10 clinical bacterial strains were isolated and characterized. Morphological and biochemical study identified these strains as Enterobacter spp., Pseudomonas spp., Yersinia spp., Escherichia spp., Salmonella spp., Proteus spp., Staphylococcus spp., Streptococcus spp., Lactobacillus spp. and Bacillus spp. Among all strains, two strains including Yersinia spp and Bacillus spp. showed higher antibiotic resistance, hence studied at molecular and physiological level. Biofilm formation capacity of strains was analyzed using three methods including Congo red assay, Test tube assay and Liquid-interface coverslip assay. Afterwards, flagellar disintegration was induced by blending and centrifugation for 5, 10 and 15 minutes. 16S rRNA sequencing showed two strains as Bacillus cereus and Yersinia enterocolitica. Both strains produced significant biofilm by all three above mentioned methods. A motility test of these blended variants showed partial/diminished motility with increased blending time. The significant loss in biofilm formation after 15 minutes blending confirmed the important flagellar contribution to the initiation of biofilm formation. This biofilm defect observed in flagella paralysed/minus variants presumably may be due to defects in attachments to surface at early stages. This study indicated that flagellar motility is crucial initially for surface attachment and subsequently for biofilm formation.}, } @article {pmid30392371, year = {2018}, author = {Kunkle, T and Abdeen, S and Salim, N and Ray, AM and Stevens, M and Ambrose, AJ and Victorino, J and Park, Y and Hoang, QQ and Chapman, E and Johnson, SM}, title = {Hydroxybiphenylamide GroEL/ES Inhibitors Are Potent Antibacterials against Planktonic and Biofilm Forms of Staphylococcus aureus.}, journal = {Journal of medicinal chemistry}, volume = {61}, number = {23}, pages = {10651-10664}, pmid = {30392371}, issn = {1520-4804}, support = {R01 GM111639/GM/NIGMS NIH HHS/United States ; R01 GM115844/GM/NIGMS NIH HHS/United States ; R01 GM120350/GM/NIGMS NIH HHS/United States ; T32 GM008804/GM/NIGMS NIH HHS/United States ; }, mesh = {Amides/*chemistry/*pharmacology ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Chaperonin 10/*antagonists & inhibitors ; Chaperonin 60/*antagonists & inhibitors ; HEK293 Cells ; Humans ; Staphylococcus aureus/*drug effects/growth & development/*physiology ; }, abstract = {We recently reported the identification of a GroEL/ES inhibitor (1, N-(4-(benzo[ d]thiazol-2-ylthio)-3-chlorophenyl)-3,5-dibromo-2-hydroxybenzamide) that exhibited in vitro antibacterial effects against Staphylococcus aureus comparable to vancomycin, an antibiotic of last resort. To follow up, we have synthesized 43 compound 1 analogs to determine the most effective functional groups of the scaffold for inhibiting GroEL/ES and killing bacteria. Our results identified that the benzothiazole and hydroxyl groups are important for inhibiting GroEL/ES-mediated folding functions, with the hydroxyl essential for antibacterial effects. Several analogs exhibited >50-fold selectivity indices between antibacterial efficacy and cytotoxicity to human liver and kidney cells in cell culture. We found that MRSA was not able to easily generate acute resistance to lead inhibitors in a gain-of-resistance assay and that lead inhibitors were able to permeate through established S. aureus biofilms and maintain their bactericidal effects.}, } @article {pmid30392142, year = {2018}, author = {Vilarrasa, J and Delgado, LM and Galofré, M and Àlvarez, G and Violant, D and Manero, JM and Blanc, V and Gil, FJ and Nart, J}, title = {In vitro evaluation of a multispecies oral biofilm over antibacterial coated titanium surfaces.}, journal = {Journal of materials science. Materials in medicine}, volume = {29}, number = {11}, pages = {164}, pmid = {30392142}, issn = {1573-4838}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/*drug effects ; Bacterial Adhesion ; Biofilms/*drug effects ; Dental Implants/microbiology ; Humans ; Surface Properties ; *Titanium ; }, abstract = {Peri-implantitis is an infectious disease that affects the supporting soft and hard tissues around dental implants and its prevalence is increasing considerably. The development of antibacterial strategies, such as titanium antibacterial-coated surfaces, may be a promising strategy to prevent the onset and progression of peri-implantitis. The aim of this study was to quantify the biofilm adhesion and bacterial cell viability over titanium disc with or without antibacterial surface treatment. Five bacterial strains were used to develop a multispecies oral biofilm. The selected species represent initial (Streptococcus oralis and Actinomyces viscosus), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late (Porphyromonas gingivalis) colonizers. Bacteria were sequentially inoculated over seven different types of titanium surfaces, combining different roughness level and antibacterial coatings: silver nanoparticles and TESPSA silanization. Biofilm formation, cellular viability and bacterial quantification over each surface were analyzed using scanning electron microscopy, confocal microscopy and real time PCR. Biofilm formation over titanium surfaces with different bacterial morphologies could be observed. TESPSA was able to significantly reduce the cellular viability when compared to all the surfaces (p < 0.05). Silver deposition on titanium surface did not show improved results in terms of biofilm adhesion and cellular viability when compared to its corresponding non-coated surface. The total amount of bacterial biofilm did not significantly differ between groups (p > 0.05). TESPSA was able to reduce biofilm adhesion and cellular viability. However, silver deposition on titanium surface seemed not to confer these antibacterial properties.}, } @article {pmid30391896, year = {2019}, author = {Cao, X and Zhang, S and Wang, H and Li, X}, title = {Azo dye as part of co-substrate in a biofilm electrode reactor-microbial fuel cell coupled system and an analysis of the relevant microorganisms.}, journal = {Chemosphere}, volume = {216}, number = {}, pages = {742-748}, doi = {10.1016/j.chemosphere.2018.10.203}, pmid = {30391896}, issn = {1879-1298}, mesh = {Azo Compounds/*chemistry ; Bioelectric Energy Sources/*trends ; Biofilms ; Electrodes ; }, abstract = {In general, refractory organics were hardly used as co-substrate in bioelectrochemical system. This study established a coupled bioelectrochemical system composed of a biofilm electrode reactor and a microbial fuel cell for using the azo dye X-3B as part of co-substrate. The two units degraded the azo dye X-3B stepwise while using it as part of co-substrate. Our results indicated that the removal efficiency of X-3B increased 28.5% using the coupled system compared with a control system. Moreover, the addition of the co-substrate glucose, which was necessary for MFC electricity generation, was reduced on the premise of stable removal efficiency in the coupled system to prevent resource waste due to using X-3B as part of co-substrate. The intermediate products of X-3B degradation were further explored using gas chromatography-mass spectrometry and a X-3B degradation pathway was proposed at the same time. Microbial communities were analyzed, illustrating that the mechanism of X-3B degradation was dependent on bioelectrochemistry rather than on microbial degradation.}, } @article {pmid30391649, year = {2019}, author = {Anupama, R and Lulu, S and Madhusmita, R and Vino, S and Mukherjee, A and Babu, S}, title = {Insights into the interaction of key biofilm proteins in Pseudomonas aeruginosa PAO1 with TiO2 nanoparticle: An in silico analysis.}, journal = {Journal of theoretical biology}, volume = {462}, number = {}, pages = {12-25}, doi = {10.1016/j.jtbi.2018.10.057}, pmid = {30391649}, issn = {1095-8541}, mesh = {Bacterial Proteins/*metabolism ; *Biofilms ; Computer Simulation ; Metal Nanoparticles/*chemistry ; Protein Binding ; Pseudomonas aeruginosa/*chemistry ; *Titanium ; Virulence ; }, abstract = {Pseudomonas aeruginosa is a pathogenic biofilm forming bacteria which exist in wide range of environments such as water, soil and human body. In an earlier study, we used a system biology approach based analysis of biofilm forming genes of P. aeruginosa and their possible role in TiO2 nanoparticle binding. The major protein of P. aeruginosa targeted by TiO2 was found to be KatA, a major catalase required for H2O2 resistance and acute virulence and the direct interacting protein partners of KatA were found to be DnaK, Hfq, RpoA and RpoS. To understand the protein-protein physical interaction characteristic of these key proteins involved in biofilm related processes, homology modeling, docking and molecular dynamic simulation were performed. For all these proteins, physical and chemical properties, amino acid composition, nest and cleft analysis were performed using online tools. The interactions between TiO2NPs-KatA and four protein-protein complexes such as KatA-DnaK, KatA-Hfq, KatA-RpoA and KatA-RpoS were studied. Our results indicate that all four key proteins and TiO2NPs can have stable complexation with KatA. The study has given enough clues to understand the interaction of TiO2NPs with P. aeruginosa biofilm in natural environment. Further investigations could lead to development of TiO2NPs based therapeutic and sanitary interventions to combat this pathogenic bacterium.}, } @article {pmid30390625, year = {2018}, author = {Cruz, CD and Shah, S and Tammela, P}, title = {Defining conditions for biofilm inhibition and eradication assays for Gram-positive clinical reference strains.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {173}, pmid = {30390625}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Caseins/chemistry ; Culture Media/*chemistry ; Enterococcus/drug effects/growth & development ; Glucose/chemistry ; Gram-Positive Bacteria/*drug effects/growth & development ; Gram-Positive Bacterial Infections/microbiology ; Limit of Detection ; Microbial Sensitivity Tests/*methods/standards ; Oxazines/chemistry ; Protein Hydrolysates/chemistry ; Reference Standards ; Staphylococcus/drug effects/growth & development ; Xanthenes/chemistry ; }, abstract = {BACKGROUND: Biofilms are formed by a complex bacterial community encapsulated by a polymeric matrix, with strong adherent properties and persistent phenotype. Biofilms are considered one of the most challenging areas of modern medicine. Existing antibiotics have been developed against free-floating bacterial cells, and thus, many treatments of biofilm-related infection fail. In this study, we compared the effects of different media on biofilm growth of clinical reference strains of Staphylococci and Enterococci, including multi-drug resistant representatives. Further, we optimized the resazurin-based assay for determining the minimal biofilm inhibitory concentration (MBIC) of standard antibiotics, and evaluated its use for the determination of minimal biofilm eradication concentration (MBEC).

RESULTS: We showed that tryptic soy broth supplemented with 1% glucose was an optimal media for maximum biofilm growth of all strains tested, with an extended incubation time for Enterococci. A range of parameters were tested for the resazurin assay, including concentration, temperature and time of incubation. Using quality parameters to analyze the assay's performance, the conditions for the resazurin assay were set as follows: 4 μg/mL and 8 μg/mL, with incubation at 25 °C for 20 min and 40 min for Staphylococci and Enterococci, respectively.

CONCLUSIONS: In summary, we defined conditions for optimal biofilm growth and for standardized resazurin assay for MBIC determination against six Gram-positive clinical reference strains. We also observed that MBEC determination by the resazurin-based assay is limited due to the poor detection limit of the assay. Complementary cell counting data is needed for precise determination of MBEC.}, } @article {pmid30390459, year = {2019}, author = {Purswani, J and Guisado, IM and Coello-Cabezas, J and González-López, J and Pozo, C}, title = {Social microbial inocula confer functional stability in a methyl tert-butyl ether extractive membrane biofilm bioreactor.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {244}, number = {}, pages = {855-860}, doi = {10.1016/j.envpol.2018.10.100}, pmid = {30390459}, issn = {1873-6424}, mesh = {Agrobacterium/*metabolism ; *Biodegradation, Environmental ; Biofilms/growth & development ; Bioreactors/*microbiology ; Methyl Ethers/*chemistry ; Paenibacillus/*metabolism ; Rhodococcus/*metabolism ; Water Pollutants, Chemical/metabolism ; Water Pollution, Chemical/analysis ; Water Purification/methods ; }, abstract = {Methyl tert-butyl ether (MTBE) degradation technologies based on two-phase partitioning systems such as extractive membrane biofilm reactors (EMBFR) permit separation of biological and contaminant compartments, thus allowing optimization of the biological section. In this study, we set-up an EMBFR with three MTBE-degrading and cooperating strains (termed social biofilm: Agrobacterium sp. MS2, Paenibacillus etheri SH7[T] and Rhodococcus ruber EE6). The removal efficiency of the social-biofilm EMBFR was 80%, and functional stability was observed in the reactor, i.e. more efficient than previous studies (single-strain inoculated EMBFR, <50% removal efficiency and unstable function). Metabolite tert-butyl alcohol was not observed, and the EC50 values were higher than those observed in single-strain EMBFRs. Comparative analysis of the MTBE enzymatic pathway and the social-biofilm was performed, where the mechanism of cooperation observed within the social-biofilm is likely due to enzymatic redundancy. Functional outcomes were equal to previous batch tests, hence 100% scalability was obtained. Overall, higher functional and stability outcomes are obtained with the use of the social-biofilm in an MTBE-EMBFR.}, } @article {pmid30390102, year = {2019}, author = {Huang, N and Pu, X and Zhang, J and Shen, H and Yang, Q and Wang, Z and Lin, B}, title = {In Vitro Formation of Dickeya zeae MS1 Biofilm.}, journal = {Current microbiology}, volume = {76}, number = {1}, pages = {100-107}, pmid = {30390102}, issn = {1432-0991}, support = {2015A030312002//Natural Science Foundation of Guangdong Province/ ; 2014J4500034//Guangzhou Science and Technology Projects (CN)/ ; 201515//President Foundation of the Guangdong Academy of Agricultural Sciences/ ; }, mesh = {Biofilms/*growth & development ; Dickeya chrysanthemi/*growth & development/isolation & purification/*metabolism ; Environment ; Microscopy, Confocal ; Musa/*microbiology ; Plant Diseases/microbiology ; Polysaccharides, Bacterial/*metabolism ; Sucrose/metabolism ; }, abstract = {Bacterial soft rot caused by Dickeya zeae MS1 (Erwinia chrysanthemi) is one of the most devastating banana diseases worldwide. However, knowledge of the development and ecological interactions of D. zeae MS1 biofilm is limited. Here, we visualized the development and architecture of D. zeae MS1 biofilm using confocal laser scanning microscopy, and we evaluated the ability of D. zeae MS1 to form biofilms under different environmental conditions (carbon sources, temperatures, pH levels and mineral elements) using a microtiter plate assay. We found that the development of D. zeae MS1 biofilm could be categorized into four phases and that mature biofilm consisted of a highly organized architecture of both bacterial cells and a self-produced matrix of extracellular polysaccharides. Furthermore, sucrose was the most suitable carbon source for supporting the growth of biofilm cells and that 32 °C and pH 7.0 were the most favorable of the temperatures and pH levels examined. Meanwhile, the addition of Ca[2+], Fe[2+], K[+] and Na[+] enhanced the formation of biofilm in minimal medium cultures, whereas 2.5 mM Cu[2+] and Mn[2+] was inhibitory. A better understanding of biofilm formation under different environmental parameters will improve our knowledge of the growth kinetics of D. zeae MS1 biofilm.}, } @article {pmid30389224, year = {2020}, author = {Ramalingam, K and Amaechi, BT}, title = {Antimicrobial effect of herbal extract of Acacia arabica with triphala on the biofilm forming cariogenic microorganisms.}, journal = {Journal of Ayurveda and integrative medicine}, volume = {11}, number = {3}, pages = {322-328}, pmid = {30389224}, issn = {0975-9476}, abstract = {BACKGROUND: Dental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease.

OBJECTIVE: Antimicrobial efficacy of a mixed herbal powder extract (MHPE) against cariogenic microorganisms was investigated.

MATERIALS AND METHODS: MIC, MBC, kinetics of killing, biofilm disruption and anticaries effect of MHPE were determined. For biofilm disruption, biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus and Candida albicans were treated with MHPE for 30 min and attached cells were quantified after staining. For live/dead staining biofilm assay, S. mutans biofilm treated with MHPE for 1min, 5min and 1 h was examined with confocal laser scanning system after live/dead staining. Efficacy was experimented by structural quality using Scanning Electron Microscope (SEM). Anticaries effect was determined by formation of caries-like lesion in continuous flow biofilm model.

RESULTS: MHPE exhibited inhibition zones ranging from 12.5 to 24.0 mm. The highest inhibition zone was recorded at concentration of 50 μg/ml. MIC for S. mutans was between 12.23 and 36.7 μg/ml, while the MBC values ranged from 36.7 to 110.65 μg/ml. Inhibitory concentration of MHPE was three fold higher than CHLX. Significant reduction of cell count (49-95%) was observed with increasing time and higher concentration. Percentage biofilm reduction compare with negative control was 96.9% (A. viscosus), 94% (C. albicans), 99.8% (L. casei) and 91.7% (S. mutans). For MHPE-treated biofilm, live/dead staining demonstrated significant (p < 0.05) higher in deceased red fluorescence areas in all kinetics points from 53.6% (1min) to 85% (1h). SEM confirmed the damage in the outer layers of S. mutans. MHPE has components with effective antibacterial activity against caries-inducing microorganisms.

CONCLUSION: The anti-adherence and anti-biofilm effect as well as the faster killing activity suggests that MHPE formula has effective antibacterial activity and could be a useful source of anti-cariogenic agents in near future.}, } @article {pmid30387879, year = {2019}, author = {Carreiro, AFP and Delben, JA and Guedes, S and Silveira, EJD and Janal, MN and Vergani, CE and Pushalkar, S and Duarte, S}, title = {Low-temperature plasma on peri-implant-related biofilm and gingival tissue.}, journal = {Journal of periodontology}, volume = {90}, number = {5}, pages = {507-515}, doi = {10.1002/JPER.18-0366}, pmid = {30387879}, issn = {1943-3670}, mesh = {*Biofilms ; Chlorhexidine ; Gingiva ; Temperature ; Titanium ; *Vascular Endothelial Growth Factor A ; }, abstract = {BACKGROUND: Evaluate the effect of low-temperature plasma (LTP) on an anaerobic biofilm and on the biological response of an in vitro reconstituted gingival epithelium tissue.

METHODS: Porphyromonas gingivalis W83 biofilm was cultured on titanium discs and reconstituted gingival tissues were submitted to similar treatment conditions.

TREATMENTS: LTP1-plasma treatment for 1 minute, LTP3-plasma treatment for 3 minute, CHX-0.2% chlorhexidine for 1 minute, GAS-gas only (no plasma) for 3 minute, and NEGATIVE-no treatment. TRITON group was included as a positive control for tissue analysis. Counting of viable colony forming units (CFU/mL) and confocal laser scanning microscopy were performed to evaluate LTP's antimicrobial effect. EpiGingival tissue was evaluated through cytotoxocity, viability, histology, and imunnohistochemistry (Ki67, vascular endothelial growth factor-A vascular endothelial growth factor A [VEGF-A], and terminal deoxynucleotidyl transferase dUTP nick end labeling terminal deoxynucleotidyl transferase dutp nick end labeling [TUNEL] expression).

RESULTS: LTP1 and LTP3 presented significantly different reduced CFU/mL reduction in comparison to the negative control (Ρ < 0.001), but it was not as effective as the positive control (CHX). Low cytotoxicity and high viability were observed in gingival epithelium of NEGATIVE, GAS, CHX, and both LTP groups. The morphologic analysis of gingival epithelium revealed minor cell damage in the plasma groups (score 1). LTP1, LTP3, GAS, and NEGATIVE groups exhibited less than 5% of basal layer positive cells. LTP1, LTP3, GAS, and CHX groups were not positive for TUNEL assay. LTP1 and LTP3 showed the most positivity for VEGF.

CONCLUSIONS: LTP treatment can be considered as an effective method for reducing P. gingivalis biofilm on implant surfaces, while being safe for the gingival epithelium. Furthermore, plasma treatment may be associated with cell repair.}, } @article {pmid30387769, year = {2018}, author = {Vogt, MS and Völpel, SL and Albers, SV and Essen, LO and Banerjee, A}, title = {Crystal structure of an Lrs14-like archaeal biofilm regulator from Sulfolobus acidocaldarius.}, journal = {Acta crystallographica. Section D, Structural biology}, volume = {74}, number = {Pt 11}, pages = {1105-1114}, doi = {10.1107/S2059798318014146}, pmid = {30387769}, issn = {2059-7983}, mesh = {Archaeal Proteins/*chemistry ; Biofilms/*growth & development ; Crystallography, X-Ray ; *Models, Molecular ; *Protein Conformation ; Sulfolobus acidocaldarius/growth & development/*metabolism ; }, abstract = {The small winged helix-turn-helix (wHTH) proteins of the Lrs14 family are major transcriptional regulators and act as archaeal biofilm regulators (AbfRs) in the crenarchaeote Sulfolobus acidocaldarius. Here, the first crystal structure of an AbfR ortholog, AbfR2, the deletion of which is known to impair biofilm formation, is presented. Like most other wHTH orthologs, AbfR2 is dimeric in solution as well as in its 2.45 Å resolution crystal structure. Given the presence of three independent AbfR2 dimers in the asymmetric unit, the crystal structure shows a considerable degree of conformational variation within the dimer, the antiparallel orientations of which are stabilized by coiled-coil interaction between H4 helices. Conserved anchor interactions between helices H0 and H4 of AbfR2 further contribute to dimer stabilization. The combined structural and bioinformatic analysis reveals cluster-specific structural differences between different members of the Lrs14 protein family.}, } @article {pmid30386734, year = {2018}, author = {Dinamarca, MA and Eyzaguirre, J and Baeza, P and Aballay, P and Canales, C and Ojeda, J}, title = {A new functional biofilm biocatalyst for the simultaneous removal of dibenzothiophene and quinoline using Rhodococcus rhodochrous and curli amyloid overproducer mutants derived from Cobetia sp. strain MM1IDA2H-1.}, journal = {Biotechnology reports (Amsterdam, Netherlands)}, volume = {20}, number = {}, pages = {e00286}, pmid = {30386734}, issn = {2215-017X}, abstract = {Biocatalyst systems based on biofilms were developed to remove nitrogen and sulfur-containing heterocyclic hydrocarbons using Cobetia sp. strain MM1IDA2H-1 and Rhodococcus rhodochrous. The curli overproducers mutants CM1 and CM4 were derived from Cobetia sp. strain and used to build monostrain biofilms to remove quinoline; and together with R. rhodochrous to simultaneously remove quinoline and dibenzothiophene using mixed biofilms. The quinoline removal using biofilms were 96% and 97% using CM1 or CM4 curli overproducers respectively, whereas bacterial suspensions assays yielded 19% and 24% with the same strains. At the other hand, the simultaneous removal of quinoline and dibenzothiophene using mixed biofilms were respectively 50% and 58% using strains R. rhodochrous with CM1 and 75% and 50% using R. rhodochrous with CM4. Results show that biofilms were more efficient than bacterial suspension assays and that in mixed biofilms the shared surface area by two or more bacteria could affect the final yield.}, } @article {pmid30385204, year = {2019}, author = {Surgers, L and Boyd, A and Girard, PM and Arlet, G and Decré, D}, title = {Biofilm formation by ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae.}, journal = {International journal of medical microbiology : IJMM}, volume = {309}, number = {1}, pages = {13-18}, doi = {10.1016/j.ijmm.2018.10.008}, pmid = {30385204}, issn = {1618-0607}, mesh = {Adhesins, Escherichia coli/metabolism ; Biofilms/*growth & development ; Bronchoalveolar Lavage ; Cross-Sectional Studies ; Escherichia coli/genetics/*growth & development/isolation & purification ; Escherichia coli Infections/blood/*microbiology/urine ; Hospitals, University ; Humans ; Klebsiella Infections/blood/*microbiology/urine ; Klebsiella pneumoniae/genetics/*growth & development/isolation & purification ; Virulence Factors/metabolism ; beta-Lactamases/metabolism ; }, abstract = {OBJECTIVES: Biofilm production in extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae provides a favourable environment for the exchange of antibiotic-resistance genes and could facilitate widespread dissemination. We aimed to assess biofilm development in ESBL-producing E. coli and K. pneumoniae isolates and determine how development relates to microbiological characteristics and clinical outcomes.

METHODS: 147 ESBL-producing E. coli and 82 K. pneumoniae were genetically characterized. Biofilm formation was measured at 1.5, 4, 6, and 24 h during culture in blood heart infusion using a microbead immobilization assay (BioFilm Ring test[®]). Results were given as biofilm formation index (BFI) with lower values indicating increased presence of biofilm (range = 0-21).

RESULTS: In total, 57.1% of strains were strong producers of biofilm (BFI < 2), whereas 13.4% lacked biofilm production (BFI > 18). Standard biofilm production (BFI < 7) was common in E. coli isolates (61.9%). For E. coli, biofilm production was less frequently observed in ST131 clones (p = 0.03) but more frequently in strains harbouring toxin (p = 0.008) or adhesin (p = 0.008) virulence factor genes. Despite almost all K. pneumoniae having standard biofilm production (90.2%), there was a 2.4-times higher odds of observing biofilm in ST29/147/323 versus other ST-types (p = 0.13). Patients with standard biofilm producing isolates were not at increased risk of transfer to intensive-care (odds-ratio=2.80, 95%CI=0.59-13.21) or death within 12-months (odds-ratio=1.61, 95%CI=0.75-3.43).

CONCLUSION: In these ESBL-producing strains, biofilm production is linked to certain virulence factors in E. coli and is common in K. pneumoniae. Further exploration of whether biofilm production increases dissemination and risk of severe clinical outcomes is needed in larger collections of isolates.}, } @article {pmid30384254, year = {2019}, author = {Khalid, HF and Tehseen, B and Sarwar, Y and Hussain, SZ and Khan, WS and Raza, ZA and Bajwa, SZ and Kanaras, AG and Hussain, I and Rehman, A}, title = {Biosurfactant coated silver and iron oxide nanoparticles with enhanced anti-biofilm and anti-adhesive properties.}, journal = {Journal of hazardous materials}, volume = {364}, number = {}, pages = {441-448}, doi = {10.1016/j.jhazmat.2018.10.049}, pmid = {30384254}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects ; Ferrosoferric Oxide/chemistry/*pharmacology ; Glycolipids/chemistry/*pharmacology ; Metal Nanoparticles/*administration & dosage/chemistry ; Pseudomonas aeruginosa/drug effects/physiology ; Silver/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/physiology ; Surface-Active Agents/chemistry/*pharmacology ; }, abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are among the hazardous biofilm forming bacteria ubiquitous in industrial/clinical wastes. Serious efforts are required to develop effective strategies to control surface-growing antibiotic resistant pathogenic bacterial communities which they are emerging as a global health issue. Blocking hazardous biofilms would be a useful aspect of biosurfactant coated nanoparticles (NPs). In this regard, we report a facile method for the synthesis of rhamnolipid (RL) coated silver (Ag) and iron oxide (Fe3O4) NPs and propose the mechanism of their synergistic antibacterial and anti-adhesive properties against biofilms formed by P. aeruginosa and S. aureus. These NPs demonstrated excellent anti-biofilm activity not only during the biofilms formation but also on the pre-formed biofilms. Mechanistically, RL coated silver (35 nm) and Fe3O4 NPs (48 nm) generate reactive oxygen species, which contribute to the antimicrobial activity. The presence of RLs shell on the nanoparticles significantly reduces the cell adhesion by modifying the surface hydrophobicity and hence enhancing the anti-biofilm property of NPs against both mentioned strains. These findings suggest that RL coated Ag and Fe3O4 NPs may be used as potent alternate to reduce the infection severity by inhibiting the biofilm formation and, therefore, they possess potential biomedical applications for antibacterial coatings and wound dressings.}, } @article {pmid30384192, year = {2019}, author = {Ripolles-Avila, C and Cervantes-Huaman, BH and Hascoët, AS and Yuste, J and Rodríguez-Jerez, JJ}, title = {Quantification of mature Listeria monocytogenes biofilm cells formed by an in vitro model: A comparison of different methods.}, journal = {International journal of food microbiology}, volume = {289}, number = {}, pages = {209-214}, doi = {10.1016/j.ijfoodmicro.2018.10.020}, pmid = {30384192}, issn = {1879-3460}, mesh = {*Biofilms ; Colony Count, Microbial/*methods ; Food-Processing Industry/*methods ; In Vitro Techniques ; Listeria monocytogenes/*physiology ; Stainless Steel ; }, abstract = {The presence of biofilms in food industrial environments is one of the main causes associated with food product contamination by L. monocytogenes. Biofilm control in the food industry is very relevant to public health and finding reliable and realistic quantification methods is essential. The aim of this study is to compare five L. monocytogenes biofilm quantification methods - conventional plate count, TEMPO, DEM, VIDAS and qPCR - and to examine a biodetector to visually detect biofilms in industrial settings. Results show that depending on the biofilm matrix production, the recovery of cells that conform the biofilm can be low and therefore, if it is an indirect method, microbial counts can be underestimated. At a species level, the methods that did not present significant differences were plate count, TEMPO (P = 0.998), DEM and qPCR (P = 0.508), so correlation studies were performed which established high correlation for plate count and TEMPO, but not for DEM and qPCR. The VIDAS method was adjusted so that it could quantify the biofilms, but the standard curve only allowed counts from 7 Log CFU cm[-2]. Results also revealed that the different strains of L. monocytogenes possess different biofilm-forming abilities, although it was not possible to correlate the capacity to produce these structures with the distinct serotypes. Last, visually detecting biofilms on stainless steel coupons proved that in industrial environments nowadays they can be rapidly and qualitatively detected so that relevant decisions can immediately be taken.}, } @article {pmid30383525, year = {2018}, author = {Nolan, LM and Whitchurch, CB and Barquist, L and Katrib, M and Boinett, CJ and Mayho, M and Goulding, D and Charles, IG and Filloux, A and Parkhill, J and Cain, AK}, title = {A global genomic approach uncovers novel components for twitching motility-mediated biofilm expansion in Pseudomonas aeruginosa.}, journal = {Microbial genomics}, volume = {4}, number = {11}, pages = {}, pmid = {30383525}, issn = {2057-5858}, support = {G1100100/MRC_/Medical Research Council/United Kingdom ; G1100189/MRC_/Medical Research Council/United Kingdom ; BB/N002539/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; MR/N023250/1/MRC_/Medical Research Council/United Kingdom ; G1100100/1/MRC_/Medical Research Council/United Kingdom ; MR/P028225/1/MRC_/Medical Research Council/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; MR/K001930/1/MRC_/Medical Research Council/United Kingdom ; WT098051/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*Biofilms ; Fimbriae, Bacterial/*genetics/ultrastructure ; Flagella/genetics ; Genes, Bacterial ; Genomics ; Locomotion/genetics ; Microscopy, Electron, Transmission ; Mutagenesis ; Pseudomonas aeruginosa/*genetics/*pathogenicity/ultrastructure ; Virulence Factors/genetics ; }, abstract = {Pseudomonas aeruginosa is an extremely successful pathogen able to cause both acute and chronic infections in a range of hosts, utilizing a diverse arsenal of cell-associated and secreted virulence factors. A major cell-associated virulence factor, the Type IV pilus (T4P), is required for epithelial cell adherence and mediates a form of surface translocation termed twitching motility, which is necessary to establish a mature biofilm and actively expand these biofilms. P. aeruginosa twitching motility-mediated biofilm expansion is a coordinated, multicellular behaviour, allowing cells to rapidly colonize surfaces, including implanted medical devices. Although at least 44 proteins are known to be involved in the biogenesis, assembly and regulation of the T4P, with additional regulatory components and pathways implicated, it is unclear how these components and pathways interact to control these processes. In the current study, we used a global genomics-based random-mutagenesis technique, transposon directed insertion-site sequencing (TraDIS), coupled with a physical segregation approach, to identify all genes implicated in twitching motility-mediated biofilm expansion in P. aeruginosa. Our approach allowed identification of both known and novel genes, providing new insight into the complex molecular network that regulates this process in P. aeruginosa. Additionally, our data suggest that the flagellum-associated gene products have a differential effect on twitching motility, based on whether components are intra- or extracellular. Overall the success of our TraDIS approach supports the use of this global genomic technique for investigating virulence genes in bacterial pathogens.}, } @article {pmid30382617, year = {2019}, author = {Smolobochkin, AV and Muravyeva, EA and Vagapova, LI and Knyazeva, IR and Voronina, JK and Burilov, AR and Pudovik, MA and Gildebrant, AV and Sazykin, IS and Sazykina, MA and Gazizov, AS}, title = {Synthesis and Evaluation of Water-Soluble 2-Aryl-1-Sulfonylpyrrolidine Derivatives as Bacterial Biofilm Formation Inhibitors.}, journal = {Chemistry & biodiversity}, volume = {16}, number = {1}, pages = {e1800490}, doi = {10.1002/cbdv.201800490}, pmid = {30382617}, issn = {1612-1880}, support = {16-13-10023//Russian Science Foundation/ ; }, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Biomass ; DNA Damage ; Pyrrolidines/*chemical synthesis/chemistry/*pharmacology ; Solubility ; Spectrum Analysis/methods ; Vibrio/*drug effects/genetics/growth & development/metabolism ; Water/chemistry ; }, abstract = {The approach to the novel 1-[(2-aminoethyl)sulfonyl]-2-arylpyrrolidines via unique intramolecular cyclization/aza-Michael reactions of N-(4,4-diethoxybutyl)ethenesulfonamide have been developed, which benefits from high yields of target compounds, mild reaction conditions, usage of inexpensive and low-toxic reagents, and allows for wide variability in both amine and aryl moieties. Biotesting with whole-cell luminescent bacterial biosensors responding to DNA damage showed that all tested compounds are not genotoxic. Tested compounds differently affect the formation of biofilms by Vibrio aquamarinus DSM 26054. Some of the tested compounds were found to suppress the bacterial biofilms growth and thus are promising candidates for further studies.}, } @article {pmid30381653, year = {2018}, author = {Kim, MK and Lee, TG and Jung, M and Park, KH and Chong, Y}, title = {In Vitro Synergism and Anti-biofilm Activity of Quercetin-Pivaloxymethyl Conjugate against Staphylococcus aureus and Enterococcus Species.}, journal = {Chemical & pharmaceutical bulletin}, volume = {66}, number = {11}, pages = {1019-1022}, doi = {10.1248/cpb.c18-00380}, pmid = {30381653}, issn = {1347-5223}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Enterococcus/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Quercetin/analogs & derivatives/chemistry/*pharmacology ; Staphylococcus aureus/*drug effects ; Structure-Activity Relationship ; }, abstract = {Upon single treatment against Staphylococus aureus, quercetin-pivaloxymethyl conjugate (Q-POM) had antibacterial activities with minimum inhibitory concentrations (MICs) of 16-32 mg/L. Q-POM showed MIC of 32 mg/L against vancomycin-resistant Enterococcus faceium (VRE), which is remarkably lower than other antibiotics investigated (≥256 mg/L). Under sub-MIC concentrations, Q-POM potentiated the activity of ampicillin, cefepime, and vancomycin against S. aureus and Enterococcus (including highly resistant strains such as hetero-resistant vancomycin-intermediate S. aureus (hVISA), vancomycin-intermediate S. aureus (VISA), and VRE), by decreasing the MICs of these antibiotics by 4-128 folds. Q-POM was found to be partially synergistic with ampicillin and cefepime against S. aureus and Enterococcus, while it was strongly synergistic with vancomycin. Q-POM at 5 mg/L inhibited the formation of biofilms of S. aureus by 24-83% and VRE by 70%. Additionally, Q-POM inhibited the hemolytic activity of S. aureus in a dose-dependent manner. Cytotoxic activity was evaluated in human liver epithelial cells (HepG2), and the 50% cytotoxicity concentration (CC50) value of Q-POM was higher than 50 mg/L. These results indicate the potential use of Q-POM in treatment of methicillin-resistant Staphylococcus aureus (MRSA) and VRE infections.}, } @article {pmid30380779, year = {2018}, author = {Yuyama, KT and Wendt, L and Surup, F and Kretz, R and Chepkirui, C and Wittstein, K and Boonlarppradab, C and Wongkanoun, S and Luangsa-Ard, J and Stadler, M and Abraham, WR}, title = {Cytochalasans Act as Inhibitors of Biofilm Formation of Staphylococcus Aureus.}, journal = {Biomolecules}, volume = {8}, number = {4}, pages = {}, pmid = {30380779}, issn = {2218-273X}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/*growth & development ; Fungi/chemistry ; Magnetic Resonance Spectroscopy ; Metabolome ; Staphylococcus aureus/*physiology ; }, abstract = {During the course of our ongoing work to discover new inhibitors of biofilm formation of Staphylococcus aureus from fungal sources, we observed biofilm inhibition by cytochalasans isolated from cultures of the ascomycete Hypoxylon fragiforme for the first time. Two new compounds were purified by a bioassay-guided fractionation procedure; their structures were elucidated subsequently by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). This unexpected finding prompted us to test further cytochalasans from other fungi and from commercial sources for comparison. Out of 21 cytochalasans, 13 showed significant inhibition of Staphylococcus aureus biofilm formation at subtoxic levels. These findings indicate the potential of cytochalasans as biofilm inhibitors for the first time, also because the minimum inhibitory concentrations (MIC) are independent of the anti-biofilm activities. However, cytochalasans are known to be inhibitors of actin, making some of them very toxic for eukaryotic cells. Since the chemical structures of the tested compounds were rather diverse, the inclusion of additional derivatives, as well as the evaluation of their selectivity against mammalian cells vs. the bacterium, will be necessary as next step in order to develop structure-activity relationships and identify the optimal candidates for development of an anti-biofilm agent.}, } @article {pmid30380712, year = {2018}, author = {Bernal-Mercado, AT and Vazquez-Armenta, FJ and Tapia-Rodriguez, MR and Islas-Osuna, MA and Mata-Haro, V and Gonzalez-Aguilar, GA and Lopez-Zavala, AA and Ayala-Zavala, JF}, title = {Comparison of Single and Combined Use of Catechin, Protocatechuic, and Vanillic Acids as Antioxidant and Antibacterial Agents against Uropathogenic Escherichia Coli at Planktonic and Biofilm Levels.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {11}, pages = {}, pmid = {30380712}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Antioxidants/chemistry/pharmacology ; Biofilms/drug effects ; Catechin/chemistry/*pharmacology ; Humans ; Hydroxybenzoates/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Plankton/drug effects ; Uropathogenic Escherichia coli/drug effects/pathogenicity ; Vanillic Acid/chemistry/*pharmacology ; }, abstract = {The objective of this study was to evaluate the effect of combining catechin, protocatechuic, and vanillic acids against planktonic growing, adhesion, and biofilm eradication of uropathogenic Escherichia coli (UPEC), as well as antioxidant agents. The minimum inhibitory concentrations (MIC) of protocatechuic, vanillic acids and catechin against the growth of planktonic bacteria were 12.98, 11.80, and 13.78 mM, respectively. Mixing 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin resulted in a synergistic effect acting as an MIC. Similarly, the minimum concentrations of phenolic compounds to prevent UPEC adhesion and biofilm formation (MBIC) were 11.03 and 7.13 mM of protocatechuic and vanillic acids, respectively, whereas no MBIC of catechin was found. However, combinations of 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin showed a synergistic effect acting as MBIC. On the other hand, the minimum concentrations to eradicate biofilms (MBEC) were 25.95 and 23.78 mM, respectively. The combination of 3.20 mM protocatechuic acid, 2.97 mM vanillic acid, and 1.72 mM catechin eradicated pre-formed biofilms. The antioxidant capacity of the combination of phenolics was higher than the expected theoretical values, indicating synergism by the DPPH[•], ABTS, and FRAP assays. Effective concentrations of catechin, protocatechuic, and vanillic acids were reduced from 8 to 1378 times when combined. In contrast, the antibiotic nitrofurantoin was not effective in eradicating biofilms from silicone surfaces. In conclusion, the mixture of phenolic compounds was more effective in preventing cell adhesion and eradicating pre-formed biofilms of uropathogenic E. coli than single compounds and nitrofurantoin, and showed antioxidant synergy.}, } @article {pmid30379419, year = {2019}, author = {Zhao, X and Yu, Y and Zhang, X and Huang, B and Bai, P and Xu, C and Li, D and Zhang, B and Liu, C}, title = {Decreased biofilm formation ability of Acinetobacter baumannii after spaceflight on China's Shenzhou 11 spacecraft.}, journal = {MicrobiologyOpen}, volume = {8}, number = {6}, pages = {e00763}, pmid = {30379419}, issn = {2045-8827}, mesh = {Acinetobacter baumannii/genetics/growth & development/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; China ; *Space Flight ; Spacecraft ; }, abstract = {China has prepared for construction of a space station by the early 2020s. The mission will require astronauts to stay on the space station for at least 180 days. Microbes isolated from the International Space Station (ISS) have shown profound resistance to clinical antibiotics and environmental stresses. Previous studies have demonstrated that the space environment could affect microbial survival, growth, virulence, biofilms, metabolism, as well as their antibiotic-resistant phenotypes. Furthermore, several studies have reported that astronauts experience a decline in their immunity during long-duration spaceflights. Monitoring microbiomes in the ISS or the spacecraft will be beneficial for the prevention of infection among the astronauts during spaceflight. The development of a manned space program worldwide not only provides an opportunity to investigate the impact of this extreme environment on opportunistic pathogenic microbes, but also offers a unique platform to detect mutations in pathogenic bacteria. Various microorganisms have been carried on a spacecraft for academic purposes. Acinetobacter baumannii is a common multidrug-resistant bacterium often prevalent in hospitals. Variations in the ability to cope with environmental hazards increase the chances of microbial survival. Our study aimed to compare phenotypic variations and analyze genomic and transcriptomic variations in A. baumannii among three different groups: SS1 (33 days on the Shenzhou 11 spacecraft), GS1 (ground control), and Aba (reference strain). Consequently, the biofilm formation ability of the SS1 strain decreased after 33 days of spaceflight. Furthermore, high-throughput sequencing revealed that some differentially expressed genes were downregulated in the SS1 strain compared with those in the GS1 strain. In conclusion, this present study provides insights into the environmental adaptation of A. baumannii and might be useful for understanding changes in the opportunistic pathogenic microbes on our spacecraft and on China's future ISS.}, } @article {pmid30378750, year = {2018}, author = {Weisel, JW and Litvinov, RI}, title = {Keeping it clean: clot biofilm to wall out bacterial invasion.}, journal = {Journal of thrombosis and haemostasis : JTH}, volume = {16}, number = {12}, pages = {2359-2361}, doi = {10.1111/jth.14309}, pmid = {30378750}, issn = {1538-7836}, mesh = {Biofilms ; *Fibrin ; Humans ; *Thrombosis ; }, } @article {pmid30377283, year = {2018}, author = {Hathroubi, S and Zerebinski, J and Ottemann, KM}, title = {Helicobacter pylori Biofilm Involves a Multigene Stress-Biased Response, Including a Structural Role for Flagella.}, journal = {mBio}, volume = {9}, number = {5}, pages = {}, pmid = {30377283}, issn = {2150-7511}, support = {R01 AI116946/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Flagella/*metabolism/ultrastructure ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Helicobacter pylori/growth & development/*physiology/ultrastructure ; Metabolic Networks and Pathways/genetics ; Microscopy, Electron, Scanning ; Sequence Analysis, RNA ; *Stress, Physiological ; }, abstract = {Helicobacter pylori has an impressive ability to persist chronically in the human stomach. Similar characteristics are associated with biofilm formation in other bacteria. The H. pylori biofilm process, however, is poorly understood. To gain insight into this mode of growth, we carried out comparative transcriptomic analysis between H. pylori biofilm and planktonic cells, using the mouse-colonizing strain SS1. Optimal biofilm formation was obtained with a low concentration of serum and 3 days of growth, conditions that caused both biofilm and planktonic cells to be ∼80% coccoid. Transcriptome sequencing (RNA-seq) analysis found that 8.18% of genes were differentially expressed between biofilm and planktonic cell transcriptomes. Biofilm-downregulated genes included those involved in metabolism and translation, suggesting these cells have low metabolic activity. Biofilm-upregulated genes included those whose products were predicted to be at the cell envelope, involved in regulating a stress response, and surprisingly, genes related to formation of the flagellar apparatus. Scanning electron microscopy visualized flagella that appeared to be a component of the biofilm matrix, supported by the observation that an aflagellated mutant displayed a less robust biofilm with no apparent filaments. We observed flagella in the biofilm matrix of additional H. pylori strains, supporting that flagellar use is widespread. Our data thus support a model in which H. pylori biofilm involves a multigene stress-biased response and that flagella play an important role in H. pylori biofilm formation.IMPORTANCE Biofilms, communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances, pose a substantial health risk and are key contributors to many chronic and recurrent infections. Chronicity and recalcitrant infections are also common features associated with the ulcer-causing human pathogen H. pylori However, relatively little is known about the role of biofilms in H. pylori pathogenesis, as well as the biofilm structure itself and the genes associated with this mode of growth. In the present study, we found that H. pylori biofilm cells highly expressed genes related to cell envelope and stress response, as well as those encoding the flagellar apparatus. Flagellar filaments were seen in high abundance in the biofilm. Flagella are known to play a role in initial biofilm formation, but typically are downregulated after that state. H. pylori instead appears to have coopted these structures for nonmotility roles, including a role building a robust biofilm.}, } @article {pmid30377199, year = {2018}, author = {Ealand, C and Rimal, B and Chang, J and Mashigo, L and Chengalroyen, M and Mapela, L and Beukes, G and Machowski, E and Kim, SJ and Kana, B}, title = {Erratum for Ealand et al., "Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation".}, journal = {Applied and environmental microbiology}, volume = {84}, number = {22}, pages = {}, doi = {10.1128/AEM.02179-18}, pmid = {30377199}, issn = {1098-5336}, } @article {pmid30376953, year = {2018}, author = {Carniello, V and Peterson, BW and van der Mei, HC and Busscher, HJ}, title = {Physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth.}, journal = {Advances in colloid and interface science}, volume = {261}, number = {}, pages = {1-14}, doi = {10.1016/j.cis.2018.10.005}, pmid = {30376953}, issn = {1873-3727}, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Chemistry, Physical ; Surface Properties ; }, abstract = {Biofilm formation is initiated by adhesion of individual bacteria to a surface. However, surface adhesion alone is not sufficient to form the complex community architecture of a biofilm. Surface-sensing creates bacterial awareness of their adhering state on the surface and is essential to initiate the phenotypic and genotypic changes that characterize the transition from initial bacterial adhesion to a biofilm. Physico-chemistry has been frequently applied to explain initial bacterial adhesion phenomena, including bacterial mass transport, role of substratum surface properties in initial adhesion and the transition from reversible to irreversible adhesion. However, also emergent biofilm properties, such as production of extracellular-polymeric-substances (EPS), can be surface-programmed. This review presents a four-step, comprehensive description of the role of physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth: (1) bacterial mass transport towards a surface, (2) reversible bacterial adhesion and (3) transition to irreversible adhesion and (4) cell wall deformation and associated emergent properties. Bacterial transport mostly occurs from sedimentation or convective-diffusion, while initial bacterial adhesion can be described by surface thermodynamic and Derjaguin-Landau-Verwey-Overbeek (DLVO)-analyses, considering bacteria as smooth, inert colloidal particles. DLVO-analyses however, require precise indication of the bacterial cell surface, which is impossible due to the presence of bacterial surface tethers, creating a multi-scale roughness that impedes proper definition of the interaction distance in DLVO-analyses. Application of surface thermodynamics is also difficult, because initial bacterial adhesion is only an equilibrium phenomenon for a short period of time, when bacteria are attached to a substratum surface through few surface tethers. Physico-chemical bond-strengthening occurs in several minutes leading to irreversible adhesion due to progressive removal of interfacial water, conformational changes in cell surface proteins, re-orientation of bacteria on a surface and the progressive involvement of more tethers in adhesion. After initial bond-strengthening, adhesion forces arising from a substratum surface cause nanoscopic deformation of the bacterial cell wall against the elasticity of the rigid peptidoglycan layer positioned in the cell wall and the intracellular pressure of the cytoplasm. Cell wall deformation not only increases the contact area with a substratum surface, presenting another physico-chemical bond-strengthening mechanism, but is also accompanied by membrane surface tension changes. Membrane-located sensor molecules subsequently react to control emergent phenotypic and genotypic properties in biofilms, most notably adhesion-associated ones like EPS production. Moreover, also bacterial efflux pump systems may be activated or mechano-sensitive channels may be opened upon adhesion-induced cell wall deformation. The physico-chemical properties of the substratum surface thus control the response of initially adhering bacteria and through excretion of autoinducer molecules extend the awareness of their adhering state to other biofilm inhabitants who subsequently respond with similar emergent properties. Herewith, physico-chemistry is not only involved in initial bacterial adhesion to surfaces but also in what we here propose to call "surface-programmed" biofilm growth. This conclusion is pivotal for the development of new strategies to control biofilm formation on substratum surfaces, that have hitherto been largely confined to the initial bacterial adhesion phenomena.}, } @article {pmid30376123, year = {2019}, author = {Naderi, J and Giles, C and Saboohi, S and Griesser, HJ and Coad, BR}, title = {Surface coatings with covalently attached anidulafungin and micafungin prevent Candida albicans biofilm formation.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {74}, number = {2}, pages = {360-364}, doi = {10.1093/jac/dky437}, pmid = {30376123}, issn = {1460-2091}, mesh = {Anidulafungin/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Immobilized Proteins/pharmacology ; Micafungin/*pharmacology ; Surface Properties ; }, abstract = {OBJECTIVES: Fungal biofilms caused by Candida spp. are a major contributor to infections originating from infected biomaterial implants. Since echinocandin-class molecules interfere with the integrity of the fungal cell wall, it was hypothesized that surface-immobilized anidulafungin and micafungin could play a role in preventing fungal adhesion and biofilm formation on surfaces.

METHODS: Anidulafungin and micafungin were covalently coupled to biomaterial surfaces and washed. Surface-sensitive instrumental analysis quantitatively and qualitatively confirmed their presence. Analysis after washing experiments provided evidence of their covalent immobilization. The in vitro antifungal properties of surfaces were confirmed using static biofilm assays and fluorescence microscopy kinetic studies.

RESULTS: Antifungal surface coatings eliminated 106 cfu/cm2 inoculations of Candida albicans and prevented biofilm formation and hyphal development on coated surfaces. Surfaces were successively exposed to fresh inoculum and were effective for at least five challenges in eliminating adherent yeasts.

CONCLUSIONS: We have observed antifungal and anti-biofilm activity of surfaces bearing conjugated echinocandins, which operate through surface contact. The analytical and biological evidence suggests an antifungal mechanism for echinocandins that does not rely upon freely diffusing molecules.}, } @article {pmid30375445, year = {2018}, author = {Shang, L and Deng, D and Buskermolen, JK and Janus, MM and Krom, BP and Roffel, S and Waaijman, T and van Loveren, C and Crielaard, W and Gibbs, S}, title = {Multi-species oral biofilm promotes reconstructed human gingiva epithelial barrier function.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {16061}, pmid = {30375445}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Coculture Techniques ; Elafin/genetics ; Epithelial Cells/microbiology/pathology ; Fibroblasts/microbiology ; Gene Expression Regulation/genetics ; Gingiva/*growth & development/microbiology ; Host-Pathogen Interactions/*genetics ; Humans ; Hydrogel, Polyethylene Glycol Dimethacrylate/pharmacology ; Microbiota/*genetics ; Mouth Mucosa/microbiology ; Primary Cell Culture/methods ; Saliva/microbiology ; Streptococcus/growth & development/pathogenicity ; Veillonella/growth & development/pathogenicity ; beta-Defensins/genetics ; }, abstract = {Since the oral mucosa is continuously exposed to abundant microbes, one of its most important defense features is a highly proliferative, thick, stratified epithelium. The cellular mechanisms responsible for this are still unknown. The aim of this study was to determine whether multi-species oral biofilm contribute to the extensive stratification and primed antimicrobial defense in epithelium. Two in vitro models were used: 3D reconstructed human gingiva (RHG) and oral bacteria representative of multi-species commensal biofilm. The organotypic RHG consists of a reconstructed stratified gingiva epithelium on a gingiva fibroblast populated hydrogel (lamina propria). Biofilm was cultured from healthy human saliva, and consists of typical commensal genera Granulicatella and major oral microbiota genera Veillonella and Streptococcus. Biofilm was applied topically to RHG and host-microbiome interactions were studied over 7 days. Compared to unexposed RHG, biofilm exposed RHG showed increased epithelial thickness, more organized stratification and increased keratinocyte proliferation. Furthermore biofilm exposure increased production of RHG anti-microbial proteins Elafin, HBD2 and HBD3 but not HBD1, adrenomedullin or cathelicidin LL-37. Inflammatory and antimicrobial cytokine secretion (IL-6, CXCL8, CXCL1, CCL20) showed an immediate and sustained increase. In conclusion, exposure of RHG to commensal oral biofilm actively contributes to RHG epithelial barrier function.}, } @article {pmid30374340, year = {2018}, author = {Tuohy, JM and Mueller-Spitz, SR and Albert, CM and Scholz-Ng, SE and Wall, ME and Noutsios, GT and Gutierrez, AJ and Sandrin, TR}, title = {MALDI-TOF MS Affords Discrimination of Deinococcus aquaticus Isolates Obtained From Diverse Biofilm Habitats.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2442}, pmid = {30374340}, issn = {1664-302X}, abstract = {Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectroscopy (MALDI-TOF MS) has been used routinely over the past decade in clinical microbiology laboratories to rapidly characterize diverse microorganisms of medical importance both at the genus and species levels. Currently, there is keen interest in applying MALDI-TOF MS at taxonomic levels beyond species and to characterize environmental isolates. We constructed a model system consisting of 19 isolates of Deinococcus aquaticus obtained from biofilm communities indigenous to diverse substrates (concrete, leaf tissue, metal, and wood) in the Fox River - Lake Winnebago system of Wisconsin to: (1) develop rapid sample preparation methods that produce high quality, reproducible MALDI-TOF spectra and (2) compare the performance of MALDI-TOF MS-based profiling to common DNA-based approaches including 16S rRNA sequencing and genomic diversity by BOX-A1R fingerprinting. Our results suggest that MALDI-TOF MS can be used to rapidly and reproducibly characterize environmental isolates of D. aquaticus at the subpopulation level. MALDI-TOF MS provided higher taxonomic resolution than either 16S rRNA gene sequence analysis or BOX-A1R fingerprinting. Spectra contained features that appeared to permit characterization of isolates into two co-occurring subpopulations. However, reliable strain-level performance required rigorous and systematic standardization of culture conditions and sample preparation. Our work suggests that MALDI-TOF MS offers promise as a rapid, reproducible, and high-resolution approach to characterize environmental isolates of members of the genus Deinococcus. Future work will focus upon application of methods described here to additional members of this ecologically diverse and ubiquitous genus.}, } @article {pmid30370437, year = {2019}, author = {Balato, G and Roscetto, E and Vollaro, A and Galasso, O and Gasparini, G and Ascione, T and Catania, MR and Mariconda, M}, title = {Bacterial biofilm formation is variably inhibited by different formulations of antibiotic-loaded bone cement in vitro.}, journal = {Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA}, volume = {27}, number = {6}, pages = {1943-1952}, pmid = {30370437}, issn = {1433-7347}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; *Bone Cements ; Humans ; Prostheses and Implants/*microbiology ; Staphylococcus epidermidis/drug effects/*growth & development ; }, abstract = {PURPOSE: The aim of the present study was to quantitatively assess biofilm growth on the surface of bone cements discs containing different antibiotics, including colistin and linezolid. Biofilms of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Staphylococcus epidermidis were grown on bone cement discs for 96 h.

METHODS: Biofilm amounts were measured by confocal laser microscopy using live/dead staining and dedicated software at different time intervals (48, 72, and 96 h).

RESULTS: Bone cement containing vancomycin was not effective at reducing MRSA biofilm formation 96 h following bacterial inoculation. At a comparable time interval, linezolid-, clindamycin-, and aminoglycoside-loaded cement was still active against this biofilm. At the 72- and 96-h observations, S. epidermidis biofilm was present only on tobramycin and gentamicin discs. P. aeruginosa biofilms were present on cement discs loaded with colistin at all time intervals starting from the 48-h observation, whereas no biofilms were detected on tobramycin or gentamicin discs.

CONCLUSION: Bone cements containing different antibiotics have variable and time-dependent windows of activity in inhibiting or reducing surface biofilm formation. The effectiveness of bone cement containing vancomycin against MRSA biofilm is questionable. The present study is clinically relevant, because it suggests that adding the right antibiotic to bone cement could be a promising approach to treat periprosthetic infections. Indeed, the antibiofilm activity of different antibiotic-loaded bone cements could be preoperatively assessed using the current methodology in two-stage exchange procedures.}, } @article {pmid30369909, year = {2018}, author = {Korany, AM and Hua, Z and Green, T and Hanrahan, I and El-Shinawy, SH and El-Kholy, A and Hassan, G and Zhu, MJ}, title = {Efficacy of Ozonated Water, Chlorine, Chlorine Dioxide, Quaternary Ammonium Compounds and Peroxyacetic Acid Against Listeria monocytogenes Biofilm on Polystyrene Surfaces.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2296}, pmid = {30369909}, issn = {1664-302X}, abstract = {Listeria monocytogenes contaminated processing equipment and the general packing environment have been implicated in deadly foodborne listeriosis outbreaks, highlighting the significance of proper sanitization and disinfection of food contact surfaces. This study aims to comprehensively evaluate antimicrobial efficacy of commercially available, economical sanitizers at practical concentrations against L. monocytogenes biofilm formed on polystyrene surfaces under different conditions. Ozonated water 1-min treatment at 1.0, 2.0, and 4.0 ppm resulted in ∼0.9, 3.4, and 4.1 log reduction of L. monocytogenes single strain biofilm grown on polystyrene surfaces, respectively. However, its efficacy was dramatically diminished in multi-strain L. monocytogenes biofilm and was further compromised by aged biofilm and in the presence of organic matter. Quaternary ammonium compounds (QAC) at 100/400 ppm, chlorine at 100/200 ppm, chlorine dioxide at 2.5/5.0 ppm and peroxyacetic acid (PAA) at 80/160 ppm resulted in 2.4/3.6, 2.0/3.1, 2.4/3.8, and 3.6/4.8 log reduction of L. monocytogenes single strain biofilm, respectively. Antimicrobial efficacies of all tested sanitizers against 7-day-old biofilm were much lower when compared to 2-day-old biofilm, with PAA being the least influenced by the age of the biofilm. Organic matter conditioning with diluted milk or apple juice dramatically impacted the antimicrobial efficacy of all sanitizers. PAA treatment of 1 min at 160-200 ppm resulted in a 3.2-3.5 log reduction against 7-day-old biofilm in the presence of organic matter, thus showing its effectiveness in eradicating L. monocytogenes biofilm on polystyrene surface. Collectively, data highlight the importance of timely and thoroughly cleaning food contact surfaces before disinfection and provides practical information and guidance for the food industry in selecting the most effective sanitizer in their sanitizing regimes to eliminate L. monocytogenes biofilm.}, } @article {pmid30369791, year = {2018}, author = {Tantivitayakul, P and Rassameemasmaung, S and Thapanabhiboonsuk, S}, title = {In vitro effect of diode laser against biofilm of Aggregatibacter actinomycetemcomitans.}, journal = {European journal of dentistry}, volume = {12}, number = {4}, pages = {485-490}, pmid = {30369791}, issn = {1305-7456}, abstract = {OBJECTIVE: The main objective is to investigate the antibacterial effect of diode laser against Aggregatibacter actinomycetemcomitans biofilm.

MATERIALS AND METHODS: Biofilms of A. actinomycetemcomitans plus Streptococcus sanguinis grown on bovine root surfaces were treated with an 810-nm diode laser using a noncontact pulsed mode with a pulse interval and pulse length of 20 ms. Four protocols, that is, one episode of 1.5 or 2.5 W for 30 s and three episodes of 1.5 or 2.5 W for 30 s were tested. No treatment and 0.2% chlorhexidine treatment served as negative and positive controls, respectively. Viable bacterial number was determined by colony counting.

RESULTS: Treatment with chlorhexidine and all laser protocols except that using single episode of 1.5 W reduced the number of A. actinomycetemcomitans in either single-species or dual-species biofilm compared to negative control. A higher percentage of A. actinomycetemcomitans reduction was demonstrated after increasing the power output or repeating the irradiation.

CONCLUSIONS: The laser protocols used in this study could reduce the number of viable bacteria but not eradicate A. actinomycetemcomitans biofilm.}, } @article {pmid30368924, year = {2018}, author = {Yan, J and Moreau, A and Khodaparast, S and Perazzo, A and Feng, J and Fei, C and Mao, S and Mukherjee, S and Košmrlj, A and Wingreen, NS and Bassler, BL and Stone, HA}, title = {Bacterial Biofilm Material Properties Enable Removal and Transfer by Capillary Peeling.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {30}, number = {46}, pages = {e1804153}, pmid = {30368924}, issn = {1521-4095}, support = {GBMF2550.06//Gordon and Betty Moore Foundation/ ; //Life Sciences Research Foundation Postdoctoral Fellowship/ ; /HHMI/Howard Hughes Medical Institute/United States ; //Max Planck Society-Alexander von Humboldt Foundation/ ; MCB-1713731//NSF/ ; MCB-1344191//NSF/ ; //Burroughs Wellcome Fund/ ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Agar ; Anti-Bacterial Agents ; *Bacterial Adhesion ; *Biofilms ; Biofouling ; Extracellular Matrix/metabolism ; Humans ; Industrial Microbiology ; *Materials Testing ; Rheology ; Stress, Mechanical ; Surface Properties ; Vibrio Infections/drug therapy ; Vibrio cholerae/*drug effects ; }, abstract = {Biofilms, surface-attached communities of bacterial cells, are a concern in health and in industrial operations because of persistent infections, clogging of flows, and surface fouling. Extracellular matrices provide mechanical protection to biofilm-dwelling cells as well as protection from chemical insults, including antibiotics. Understanding how biofilm material properties arise from constituent matrix components and how these properties change in different environments is crucial for designing biofilm removal strategies. Here, using rheological characterization and surface analyses of Vibrio cholerae biofilms, it is discovered how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Using insight gained from our measurements, a facile capillary peeling technology is developed to remove biofilms from surfaces or to transfer intact biofilms from one surface to another. It is shown that the findings are applicable to other biofilm-forming bacterial species and to multiple surfaces. Thus, the technology and the understanding that have been developed could potentially be employed to characterize and/or treat biofilm-related infections and industrial biofouling problems.}, } @article {pmid30368608, year = {2019}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Effects of medium components in a glycerol-based medium on vitamin K (menaquinone-7) production by Bacillus subtilis natto in biofilm reactors.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {2}, pages = {223-232}, doi = {10.1007/s00449-018-2027-8}, pmid = {30368608}, issn = {1615-7605}, support = {Project PEN04561 and Accession number 1002249//USDA National Institute of Food and Agriculture Federal Appropriations/ ; }, mesh = {Bacillus subtilis/*metabolism ; *Biofilms ; Bioreactors ; Culture Media/chemistry ; Fermentation ; Glycerol/*chemistry ; Vitamin K/*chemistry ; Vitamin K 2/*analogs & derivatives/chemistry ; }, abstract = {Menaquinone-7 (MK-7) as the most important form of Vitamin K has been reported to have miraculous benefits such as preventing cardiovascular diseases and osteoporosis along with antitumor effects. Therefore, there have been numerous studies in the past decades to improve MK-7 production via microbial fermentation. Unfortunately, both solid and liquid state fermentation strategies that are utilized for MK-7 production, face fundamental operational and scale-up issues as well as intense heat and mass transfer problems during fermentation. In this regard, biofilm reactors seem to be a practical solution to overcome these issues and enhance the production in agitated liquid fermentation. Therefore, this study was undertaken to utilize biofilm reactors in investigating and optimizing different media components in a glycerol-based medium. Using response surface methodology, the effects of glycerol, yeast extract, and soytone were studied in the fermentation medium on MK-7 production in biofilm reactor. With a composition of 48.2 g/L of glycerol, 8.1 g/L of yeast extracts, 13.6 g/L of soytone and 0.06 g/L of K2HPO4, MK-7 concentrations could reach 14.7 ± 1.4 mg/L in biofilm reactors, which was 57% higher compared to the MK-7 concentration achieved in suspended-cell reactors under similar conditions, while glycerol was depleted by the end of the fifth day in biofilm reactors, but glycerol was never depleted in suspended-cell reactors. Evidently, biofilm reactors present a reliable strategy to address the operational issues that occur during MK-7 biosynthesis on an industrial scale production.}, } @article {pmid30368594, year = {2018}, author = {Irankhah, S and Abdi Ali, A and Reza Soudi, M and Gharavi, S and Ayati, B}, title = {Highly efficient phenol degradation in a batch moving bed biofilm reactor: benefiting from biofilm-enhancing bacteria.}, journal = {World journal of microbiology & biotechnology}, volume = {34}, number = {11}, pages = {164}, pmid = {30368594}, issn = {1573-0972}, support = {96001722//National Foundation for Science and Technology Development/ ; }, mesh = {Acinetobacter/growth & development/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Bioreactors/*microbiology ; Phenol/*metabolism ; Pseudomonas/growth & development/*metabolism ; Sewage/*microbiology ; }, abstract = {In this study, the efficiency improvement of three moving bed biofilm reactors (MBBRs) was investigated by inoculation of activated sludge cells (R1), mixed culture of eight strong phenol-degrading bacteria consisted of Pseudomonas spp. and Acinetobacter spp. (R2) and the combination of both (R3). Biofilm formation ability of eight bacteria was assessed initially using different methods and media. Maximum degradation of phenol, COD, biomass growth and also changes in organic loading shock were used as parameters to measure the performance of reactors. According to the results, all eight strains were determined as enhanced biofilm forming bacteria (EBFB). Under optimum operating conditions, more than 90% of initial COD load of 2795 mg L[-1] was reduced at 24 HRT in R3 while this reduction efficiency was observed in concentrations of 1290 mg L[-1] and 1935 mg L[-1], in R1 and R2, respectively. When encountering phenol loading shock-twice greater than optimum amount-R1, R2 and R3 managed to return to the steady-state condition within 32, 24 and 18 days, respectively. SEM microscopy and biomass growth measurements confirmed the contribution of more cells to biofilm formation in R3 followed by R2. Additionally, established biofilm in R3 was more resistant to phenol loading shock which can be attributed to the enhancer role of EBFB strains in this reactor. It has been demonstrated that the bacteria with both biofilm-forming and contaminant-degrading abilities are not only able to promote the immobilization of other favorable activated sludge cells in biofilm structure, but also cooperate in contaminant degradation which all consequently lead to improvement of treatment efficiency.}, } @article {pmid30368202, year = {2019}, author = {Naumova, EA and Weber, L and Pankratz, V and Czenskowski, V and Arnold, WH}, title = {Bacterial viability in oral biofilm after tooth brushing with amine fluoride or sodium fluoride.}, journal = {Archives of oral biology}, volume = {97}, number = {}, pages = {91-96}, doi = {10.1016/j.archoralbio.2018.10.013}, pmid = {30368202}, issn = {1879-1506}, mesh = {Adult ; Amines/*pharmacology ; Biofilms/*drug effects ; Cariostatic Agents/*pharmacology ; Colony Count, Microbial ; Female ; Healthy Volunteers ; Humans ; Male ; Microbial Viability/*drug effects ; Microscopy, Fluorescence ; Sodium Fluoride/*pharmacology ; Time Factors ; *Toothbrushing ; }, abstract = {OBJECTIVE: The aim of this study was to investigate the effects of sodium fluoride (NaF) and amine fluoride (AmF) on bacterial viability in the oral cavity.

MATERIAL AND METHODS: Healthy subjects brushed their teeth with either fluoride free toothpaste, NaF- or AmF-containing toothpaste. Biofilm smears from different locations were collected before and immediately and 30 and 120 min after tooth brushing. The smears were stained with live/dead bacterial staining, and the number of the respective bacteria was counted. The data were statistically analyzed by comparing the numbers of bacteria before and after the application of no fluoride, NaF and AmF.

RESULTS: The highest numbers of bacteria were found in the tongue biofilm, followed by the palatal and cheek biofilm. The lowest numbers were found in the mouth floor biofilm. After the application of AmF, no changes in the numbers of bacteria were found in the biofilms, except for the cheek, where they were reduced. After the application of NaF, the number of bacteria decreased significantly in all biofilms. After 120 min, bacterial regrowth was complete.

CONCLUSIONS: AmF has only little effect on the bacterial viability of oral biofilms. NaF application reduces the number of living bacteria in the oral biofilms. This effect lasts not longer than 120 min.}, } @article {pmid30366999, year = {2019}, author = {Kharadi, RR and Castiblanco, LF and Waters, CM and Sundin, GW}, title = {Phosphodiesterase Genes Regulate Amylovoran Production, Biofilm Formation, and Virulence in Erwinia amylovora.}, journal = {Applied and environmental microbiology}, volume = {85}, number = {1}, pages = {}, pmid = {30366999}, issn = {1098-5336}, support = {R01 GM109259/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Erwinia amylovora/genetics/pathogenicity/*physiology ; Phosphoric Diester Hydrolases/*genetics/metabolism ; Plant Diseases/microbiology ; Polysaccharides, Bacterial/*biosynthesis ; Virulence ; }, abstract = {Cyclic di-GMP (c-di-GMP) is a ubiquitous bacterial second messenger molecule that is an important virulence regulator in the plant pathogen Erwinia amylovora Intracellular levels of c-di-GMP are modulated by diguanylate cyclase (DGC) enzymes that synthesize c-di-GMP and by phosphodiesterase (PDE) enzymes that degrade c-di-GMP. The regulatory role of the PDE enzymes in E. amylovora has not been determined. Using a combination of single, double, and triple deletion mutants, we determined the effects of each of the four putative PDE-encoding genes (pdeA, pdeB, pdeC, and edcA) in E. amylovora on cellular processes related to virulence. Our results indicate that pdeA and pdeC are the two phosphodiesterases most active in virulence regulation in E. amylovora Ea1189. The deletion of pdeC resulted in a measurably significant increase in the intracellular pool of c-di-GMP, and the highest intracellular concentrations of c-di-GMP were observed in the Ea1189 ΔpdeAC and Ea1189 ΔpdeABC mutants. The regulation of virulence traits due to the deletion of the pde genes showed two patterns. A stronger regulatory effect was observed on amylovoran production and biofilm formation, where both Ea1189 ΔpdeA and Ea1189 ΔpdeC mutants exhibited significant increases in these two phenotypes in vitro In contrast, the deletion of two or more pde genes was required to affect motility and virulence phenotypes. Our results indicate a functional redundancy among the pde genes in E. amylovora for certain traits and indicate that the intracellular degradation of c-di-GMP is mainly regulated by pdeA and pdeC, but they also suggest a role for pdeB in regulating motility and virulence.IMPORTANCE Precise control of the expression of virulence genes is essential for successful infection of apple hosts by the fire blight pathogen, Erwinia amylovora The presence and buildup of a signaling molecule called cyclic di-GMP enables the expression and function of some virulence determinants in E. amylovora, such as amylovoran production and biofilm formation. However, other determinants, such as those for motility and the type III secretion system, are expressed and functional when cyclic di-GMP is absent. Here, we report studies of enzymes called phosphodiesterases, which function in the degradation of cyclic di-GMP. We show the importance of these enzymes in virulence gene regulation and the ability of E. amylovora to cause plant disease.}, } @article {pmid30366231, year = {2019}, author = {Rago, L and Zecchin, S and Villa, F and Goglio, A and Corsini, A and Cavalca, L and Schievano, A}, title = {Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {125}, number = {}, pages = {105-115}, doi = {10.1016/j.bioelechem.2018.10.002}, pmid = {30366231}, issn = {1878-562X}, mesh = {Archaea/genetics/physiology ; Autotrophic Processes ; *Biofilms ; Biomass ; Bioreactors/*microbiology ; Carbon/*metabolism ; Electrochemical Techniques/*instrumentation ; Electrodes ; Equipment Design ; *Nitrogen Fixation ; Nitrogen-Fixing Bacteria/genetics/isolation & purification/*physiology ; Phylogeny ; }, abstract = {A new approach to microbial electrosynthesis is proposed, aimed at producing whole biomass from N2 and inorganic carbon, by electrostimulation of complex microbial communities. On a carbon-based conductor under constant polarization (-0.7 V vs SHE), an electroactive biofilm was enriched with autotrophic nitrogen fixing microorganims and led to biomass synthesis at higher amounts (up to 18 fold), as compared to controls kept at open circuit (OC). After 110 days, the electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated with autotrophs (both Archaea and Bacteria) only in polarized biofilms, but not in OC. With this first proof of concept experiment, we propose to call this promising field 'bioelectrochemical nitrogen fixation' (e-BNF): a possible way to 'power' biological nitrogen fixation, organic carbon storage and soil fertility against desertification, and possibly a new tool to study the development of early prokaryotic life in extreme environments.}, } @article {pmid30365642, year = {2018}, author = {Borges, KRA and Pimentel, IV and Lucena, LCLDS and Silva, MACND and Monteiro, SG and Monteiro, CA and Nascimento, MDDSB and Bezerra, GFB}, title = {Adhesion and biofilm formation of Candida parapsilosis isolated from vaginal secretions to copper intrauterine devices.}, journal = {Revista do Instituto de Medicina Tropical de Sao Paulo}, volume = {60}, number = {}, pages = {e59}, pmid = {30365642}, issn = {1678-9946}, mesh = {Biofilms/*growth & development ; Candida parapsilosis/isolation & purification/*physiology ; Candidiasis, Vulvovaginal/etiology/*microbiology ; Equipment Contamination ; Female ; Humans ; Intrauterine Devices, Copper/adverse effects/*microbiology ; Prospective Studies ; }, abstract = {INTRODUCTION: Candida parapsilosis is one of the main species that is able to adhere to forming biofilms on inert materials. Adhesion is the first step towards the colonization and invasion of host cells during the infectious process. Among the infections, vulvovaginal candidiasis is increasingly common. The objective was to evaluate the profile of adherence and biofilm formation of eight isolates of C. parapsilosis on the metal used in intrauterine devices (IUDs).

METHODS: Eight strains of C. parapsilosis presenting strong adhesion and biofilm formation properties were isolated from vaginal secretions in a previous study. To assay the adhesion and biofilm formation, copper fragments were made and cultivated in tubes containing 3 mL of phosphate-buffered saline and incubated for 6 and 24 h at 37 °C to evaluate biofilm formation. After incubation, the intensity of adherence and of biofilm formation on copper fragments were determined by performing a colony count.

RESULTS: All isolates were able to form biofilms and the isolate Cp62 showed many cells joined in a planktonic mode forming biofilms. The use of an IUD is one of the main factors that favors vulvovaginal candidiasis, and the presence of copper in this device increases the chance of recurrent vulvovaginal candidiasis (CVVR) due to the ease with which species of the genus Candida can adhere to inert surfaces.

CONCLUSION: This research showed that the clinical isolates studied adhered to IUD copper fragments and formed biofilms, further increasing their virulence.}, } @article {pmid30364807, year = {2018}, author = {Midha, A and Janek, K and Niewienda, A and Henklein, P and Guenther, S and Serra, DO and Schlosser, J and Hengge, R and Hartmann, S}, title = {Corrigendum: The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {367}, doi = {10.3389/fcimb.2018.00367}, pmid = {30364807}, issn = {2235-2988}, abstract = {[This corrects the article DOI: 10.3389/fcimb.2018.00271.].}, } @article {pmid30363861, year = {2018}, author = {Farkash, Y and Feldman, M and Ginsburg, I and Steinberg, D and Shalish, M}, title = {Green Tea Polyphenols and Padma Hepaten Inhibit Candida albicans Biofilm Formation.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2018}, number = {}, pages = {1690747}, pmid = {30363861}, issn = {1741-427X}, abstract = {Candida albicans (C. albicans) is the most prevalent opportunistic human pathogenic fungus and can cause mucosal membrane infections and invade the blood. In the oral cavity, it can ferment dietary sugars, produce organic acids and therefore has a role in caries development. In this study, we examined whether the polyphenol rich extractions Polyphenon from green tea (PPFGT) and Padma Hepaten (PH) can inhibit the caries-inducing properties of C. albicans. Biofilms of C. albicans were grown in the presence of PPFGT and PH. Formation of biofilms was tested spectrophotometrically after crystal violet staining. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy (CSLM). Treated C. albicans morphology was demonstrated using scanning electron microscopy (SEM). Expression of virulence-related genes was tested using qRT-PCR. Development of biofilm was also tested on an orthodontic surface (Essix) to assess biofilm inhibition ability on such appliances. Both PPFGT and PH dose-dependently inhibited biofilm formation, with no inhibition on planktonic growth. The strongest inhibition was obtained using the combination of the substances. Crystal violet staining showed a significant reduction of 45% in biofilm formation using a concentration of 2.5mg/ml PPFGT and 0.16mg/ml PH. A concentration of 1.25 mg/ml PPFGT and 0.16 mg/ml PH inhibited candidal growth by 88% and EPS secretion by 74% according to CSLM. A reduction in biofilm formation and in the transition from yeast to hyphal morphotype was observed using SEM. A strong reduction was found in the expression of hwp1, eap1, and als3 virulence associated genes. These results demonstrate the inhibitory effect of natural PPFGT polyphenolic extraction on C. albicans biofilm formation and EPS secretion, alone and together with PH. In an era of increased drug resistance, the use of phytomedicine to constrain biofilm development, without killing host cells, may pave the way to a novel therapeutic concept, especially in children as orthodontic patients.}, } @article {pmid30361978, year = {2018}, author = {Kim, SK and Li, XH and Hwang, HJ and Lee, JH}, title = {Antibiofilm effect of biofilm-dispersing agents on clinical isolates of Pseudomonas aeruginosa with various biofilm structures.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {56}, number = {12}, pages = {902-909}, pmid = {30361978}, issn = {1976-3794}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*classification/*drug effects/growth & development ; Day Care, Medical ; Genes, Fungal/genetics ; Hospitals ; Humans ; Mutation ; Nitroprusside/pharmacology ; Pseudomonas aeruginosa/*drug effects/genetics/isolation & purification ; Republic of Korea ; ortho-Aminobenzoates/pharmacology ; }, abstract = {Pseudomonas aeruginosa, an opportunistic human pathogen, causes many biofilm-mediated chronic infections. In this study, biofilm structures of various clinical strains of P. aeruginosa isolated from hospitalized patients were examined and their influence on the biofilm-dispersing effects of chemicals was investigated. The clinical isolates formed structurally distinct biofilms that could be classified into three different groups: 1) mushroom-like, 2) thin flat, and 3) thick flat structures. A dispersion of these differently structured biofilms was induced using two biofilm-dispersing agents, anthranilate and sodium nitroprusside (SNP). Although both SNP and anthranilate could disperse all types of biofilms, the thick flat biofilms were dispersed less efficiently than the biofilms of other structures. This suggests that biofilm-dispersing agents have higher potency on the biofilms of porous structures than on densely packed biofilms.}, } @article {pmid30360241, year = {2019}, author = {Song, Z and Zhang, X and Ngo, HH and Guo, W and Song, P and Zhang, Y and Wen, H and Guo, J}, title = {Zeolite powder based polyurethane sponges as biocarriers in moving bed biofilm reactor for improving nitrogen removal of municipal wastewater.}, journal = {The Science of the total environment}, volume = {651}, number = {Pt 1}, pages = {1078-1086}, doi = {10.1016/j.scitotenv.2018.09.173}, pmid = {30360241}, issn = {1879-1026}, mesh = {*Bacterial Physiological Phenomena ; *Biofilms ; *Bioreactors ; Cities ; Nitrogen/*analysis ; Polyurethanes/chemistry ; Powders ; Waste Disposal, Fluid/*methods ; Wastewater/*analysis ; Zeolites/*chemistry ; }, abstract = {This study aims to enhance nitrogen removal efficiency of a moving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 ± 4.8% of TN was removed in Z-MBBR compared to 75.1 ± 6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 ± 4.1% and 81.7 ± 6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 ± 0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 ± 0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater.}, } @article {pmid30357538, year = {2018}, author = {Cao, W and Zhang, Y and Wang, X and Li, Q and Xiao, Y and Li, P and Wang, L and Ye, Z and Xing, X}, title = {Novel resin-based dental material with anti-biofilm activity and improved mechanical property by incorporating hydrophilic cationic copolymer functionalized nanodiamond.}, journal = {Journal of materials science. Materials in medicine}, volume = {29}, number = {11}, pages = {162}, pmid = {30357538}, issn = {1573-4838}, support = {No. 81460107//the Natural Science Foundation of China/ ; }, mesh = {Animals ; Biofilms/*drug effects ; Cell Survival/drug effects ; *Dental Materials ; Mechanics ; Mice ; Nanodiamonds/*chemistry ; Polymers/*chemistry ; RAW 264.7 Cells ; Streptococcus mutans/drug effects ; }, abstract = {There is an increasing clinical need to design dental restorative materials that combine excellent mechanical property and anti-biofilm activity. In the current study, photocurable polycation functionalized nanodiamond (QND) was synthesized and proposed as novel filler for dental resins. By reason of increased repulsive force between nanoparticles and enhanced compatibility with resin matrix, QND dispersed uniformly in reinforced resins, which would help to transfer stress and deformation from the matrix to fillers more efficiently, resulting in a significant improvement in mechanical properties. Notably, the Vickers's hardness, flexural strength and flexural modulus of resins containing 1.0 wt% QND were 44.5, 36.1 and 41.3% higher than that of control, respectively. The antibacterial activity against Streptococcus mutans (S. mutans) showed that QND-incorporated resins produced anti-adhesive property due to their hydrophilic surfaces and could suppress bacterial growth as a result of the contact-killing effect of embedded nanocomposites. As the synergistic effect of anti-adhesive and bactericidal performance, resins loading 1.0~1.5 wt% QNDs displayed excellent anti-biofilm activity. Meanwhile, the results of macrophage cytotoxicity showed that the proliferation of RAW 264.7 cells remained 84.3%, even at a concentration of 1.0 wt% QNDs after 7-day incubation. Therefore, the QND-containing dental resin with the combination of high mechanical property, bacteria-repellent capability and antibacterial performance holds great potential as a restorative material based on this scheme.}, } @article {pmid30357139, year = {2018}, author = {Parandhaman, T and Das, SK}, title = {Facile synthesis, biofilm disruption properties and biocompatibility study of a poly-cationic peptide functionalized graphene-silver nanocomposite.}, journal = {Biomaterials science}, volume = {6}, number = {12}, pages = {3356-3372}, doi = {10.1039/c8bm01003j}, pmid = {30357139}, issn = {2047-4849}, mesh = {Animals ; Anti-Bacterial Agents/*chemical synthesis/pharmacology/toxicity ; Antimicrobial Cationic Peptides/*chemistry/pharmacology/toxicity ; Biofilms/*drug effects ; Graphite/*chemistry ; Microwaves ; Nanocomposites/*chemistry ; Silver/*chemistry ; Zebrafish ; }, abstract = {Bacterial colonization and biofilm formation is a growing challenge in the biomedical field. Although nanotechnology has emerged as an alternative strategy to combat biofilm formation, the toxicity of nanomaterials is a major concern. In this study, we report a safe-by-design strategy for the synthesis of a poly-cationic peptide functionalized graphene-silver nanocomposite (designated as GAPP) and its enhanced biofilm inhibition and disruption properties to eliminate the biofilm development of Gram-negative bacteria. The graphene-silver (rGOAg) nanocomposite was synthesized by microwave reduction, and subsequently functionalized with an antimicrobial poly-cationic peptide through covalent bonding. The results demonstrated that GAPP effectively killed the planktonic cells and biofilms of Escherichia coli and Pseudomonas aeruginosa depending upon the concentration and duration of the interaction. The complete eradication of preformed biofilm was achieved when treated with 10 μg mL-1 of GAPP for 5 h. The GAPP exerted bactericidal and biofilm inhibition activity through a "contact-kill-release" mode of action, wherein the electrostatic interaction of GAPP with the bacterial cells induced physical disruption accompanied by ROS-mediated biochemical changes. The internalization of GAPP into the cytoplasm through the damaged membrane led to metabolic imbalance in the cells. The peptide functionalization further prevented the dissolution of Ag+ ions, thus minimizing the cytotoxicity of GAPP to adult zebrafish. More importantly, the poly-cationic peptide functionalization enhanced the bioavailability, biofilm inhibition and disruption activities of GAPP, while minimizing its toxicological impact. The results obtained thereby provide an effective strategy in the design of alternative antibacterial agents for fighting biofilms of Gram-negative bacteria.}, } @article {pmid30356998, year = {2018}, author = {Yu, L and Shang, F and Chen, X and Ni, J and Yu, L and Zhang, M and Sun, D and Xue, T}, title = {The anti-biofilm effect of silver-nanoparticle-decorated quercetin nanoparticles on a multi-drug resistant Escherichia coli strain isolated from a dairy cow with mastitis.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5711}, pmid = {30356998}, issn = {2167-8359}, abstract = {BACKGROUND: Escherichia coli is an important opportunistic pathogen that could cause inflammation of the udder in dairy cows resulting in reduced milk production and changes in milk composition and quality, and even death of dairy cows. Therefore, mastitis is the main health issue which leads to major economic losses on dairy farms. Antibiotics are routinely used for the treatment of bovine mastitis. The ability to form biofilm increases the antibiotic resistance of E. coli. Nanoparticles (NPs), a nanosized, safe, and highly cost-effective antibacterial agent, are potential biomedical tools. Given their antibacterial activities, silver nanoparticles (Ag NPs) have a broad range of applications.

METHODS: In this study, we performed antibacterial activity assays, biofilm formation assays, scanning electron microscopy (SEM) experiments, and real-time reverse transcription PCR (RT-PCR) experiments to investigate the antibacterial and anti-biofilm effect of quercetin, Ag NPs, and Silver-nanoparticle-decorated quercetin nanoparticles (QA NPs) in E. coli strain ECDCM1.

RESULTS: In this study, QA NPs, a composite material combining Ag NPs and the plant-derived drug component quercetin, exhibited stronger antibacterial and anti-biofilm properties in a multi-drug resistant E. coli strain isolated from a dairy cow with mastitis, compared to Ag NPs and Qe.

DISCUSSION: This study provides evidence that QA NPs possess high antibacterial and anti-biofilm activities. They proved to be more effective than Ag NPs and Qe against the biofilm formation of a multi-drug resistant E. coli isolated from cows with mastitis. This suggests that QA NPs might be used as a potential antimicrobial agent in the treatment of bovine mastitis caused by E. coli.}, } @article {pmid30356392, year = {2018}, author = {Takesh, T and Ho, J and Firmalino, MV and Islip, D and Anbarani, A and Wilder-Smith, P}, title = {Effects of a Novel Formulation on Oral Biofilm, pH Buffering, and Gingival Health in Patients with Dry Mouth.}, journal = {International journal of dentistry}, volume = {2018}, number = {}, pages = {2748274}, pmid = {30356392}, issn = {1687-8728}, abstract = {GOAL: To identify in patients with dry mouth the effects of a novel test agent (Oral Essentials Hydrating Formula Mouthwash, Beverly Hills, CA) versus a control agent (Biotène Dry Mouth Oral Rinse, GlaxoSmithKline Consumer Healthcare L.P., Moon Township, PA, USA) versus no treatment on dry mouth, plaque, salivary pH and buffering capacity, gingival health, and tooth sensitivity.

MATERIALS AND METHODS: In this cross-over study, ten subjects with dry mouth used test and control dry mouth interventions, as well as no dry mouth intervention in randomized sequence. Plaque Index, Gingival Index, Sulcus Bleeding Index, Plaque staining, and photographs were recorded at baseline and end of each study arm. Salivary volume, pH, and buffering capacity were also recorded at these time points. Additionally, subjects completed a questionnaire for dry mouth and dentinal sensitivity at each visit.

RESULTS: Reductions in plaque presence and clinical indices were similar after use of test or control products (p < 0.05). Saliva volume and pH buffering improved significantly after use of test and control products (p < 0.05).

CONCLUSIONS: The effects of a novel dry mouth intervention are similar to those of an existing OTC remedy and are significantly better than no intervention.}, } @article {pmid30355991, year = {2018}, author = {Zhang, Y and Xia, B and Li, M and Shi, J and Long, Y and Jin, Y and Bai, F and Cheng, Z and Jin, S and Wu, W}, title = {HigB Reciprocally Controls Biofilm Formation and the Expression of Type III Secretion System Genes through Influencing the Intracellular c-di-GMP Level in Pseudomonas aeruginosa.}, journal = {Toxins}, volume = {10}, number = {11}, pages = {}, pmid = {30355991}, issn = {2072-6651}, mesh = {Bacterial Proteins/*physiology ; Bacterial Toxins ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; *Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*physiology ; Type III Secretion Systems/*genetics ; }, abstract = {Toxin-antitoxin (TA) systems play important roles in bacteria persister formation. Increasing evidence demonstrate the roles of TA systems in regulating virulence factors in pathogenic bacteria. The toxin HigB in Pseudomonas aeruginosa contributes to persister formation and regulates the expression of multiple virulence factors and biofilm formation. However, the regulatory mechanism remains elusive. In this study, we explored the HigB mediated regulatory pathways. We demonstrate that HigB decreases the intracellular level of c-di-GMP, which is responsible for the increased expression of the type III secretion system (T3SS) genes and repression of biofilm formation. By analyzing the expression levels of the known c-di-GMP metabolism genes, we find that three c-di-GMP hydrolysis genes are up regulated by HigB, namely PA2133, PA2200 and PA3825. Deletion of the three genes individually or simultaneously diminishes the HigB mediated regulation on the expression of T3SS genes and biofilm formation. Therefore, our results reveal novel functions of HigB in P. aeruginosa.}, } @article {pmid30355820, year = {2018}, author = {Georgiev, KG and Filipov, IA and Dobrev, IN}, title = {In Vivo Collection and SEM Identification of Oral Biofilm Using Indirect Composite Prototype Restorations. Clinical and Laboratory Study.}, journal = {Folia medica}, volume = {60}, number = {2}, pages = {300-307}, doi = {10.1515/folmed-2017-0092}, pmid = {30355820}, issn = {0204-8043}, mesh = {*Biofilms ; *Composite Resins ; DMF Index ; Dental Plaque ; *Dental Restoration, Temporary ; Humans ; Microscopy, Electron, Scanning ; }, abstract = {BACKGROUND: The oral ecosystem is a dynamic environment inhabited by more than 700 microbial taxa. Recent studies report that multispecies oral biofilms develop on the surface of resin composites leading to degradation of its organic matrix and altered structural stability of the restoration.

AIM: To examine the efficacy of a novel clinical approach to investigating in vivo formed biofilms on resin composite surfaces.

MATERIALS AND METHODS: The clinical protocol of this study implemented indirect composite molar restorations (from resin material Filtek Z250, 3M ESPE) as intraoral biofilm carriers (test devices). We recruited for the experiment 5 consenting adult subjects with indications for indirect molar restoration. For each subject we fabricated 4 indirect restorations, 3 of which dedicated to different intraoral duration - 3, 7, and 14 days. All composite carriers were fixed temporarily for the intended time period and consecutively replaced. The detached carriers were prepared for microscope analysis at each time interval. The fourth composite carrier was used as the definitive restoration.

RESULTS: The timeline of the biofilm formation and the microbial morphology were associated with previous studies of in vivo bacterial colonisation. A correlation between the plaque formation cycle and the DMFt indices of the subjects was established.

CONCLUSIONS: The implementation of indirect composite restorations as intraoral biofilm carrier offers valuable contribution to the real time investigation of in vivo biofilm accumulation.}, } @article {pmid30354689, year = {2018}, author = {Mello, TP and Oliveira, SSC and Frasés, S and Branquinha, MH and Santos, ALS}, title = {Surface properties, adhesion and biofilm formation on different surfaces by Scedosporium spp. and Lomentospora prolificans.}, journal = {Biofouling}, volume = {34}, number = {7}, pages = {800-814}, doi = {10.1080/08927014.2018.1503652}, pmid = {30354689}, issn = {1029-2454}, mesh = {Ascomycota/*chemistry ; *Biofilms ; Catheters/microbiology ; Hydrophobic and Hydrophilic Interactions ; Melanins/chemistry ; Scedosporium/*chemistry ; Spores, Fungal/*chemistry ; Surface Properties ; }, abstract = {In the present work, some surface properties of the fungi Scedosporium apiospermum, S. aurantiacum, S. minutisporum, and Lomentospora prolificans and their capability to adhere to and form a biofilm on diverse surfaces were evaluated. All four species had high conidial surface hydrophobicity and elevated electronegative zeta potentials. Abundant quantities of melanin were detected at the conidial surface, whereas sialic acid was absent. The numbers of non-germinated and germinated conidia adhered to poly-L-lysine-covered slides was higher than on glass after 4 h of fungi-surface contact. Additionally, after 72 h of interaction a typical biofilm structure had formed. Mature biofilms were also observed after 72 h on a nasogastric catheter (made from polyvinyl chloride), a late bladder catheter (siliconized latex), and a nasoenteric catheter (polyurethane). Interestingly, biofilm biomass increased considerably when the catheters had previously been incubated with serum. These results confirm that Scedosporium/Lomentospora spp. are capable of forming biofilms on diverse abiotic surfaces.}, } @article {pmid30354082, year = {2018}, author = {Zhang, N and Thompson, CEL and Townend, IH and Rankin, KE and Paterson, DM and Manning, AJ}, title = {Nondestructive 3D Imaging and Quantification of Hydrated Biofilm-Sediment Aggregates Using X-ray Microcomputed Tomography.}, journal = {Environmental science & technology}, volume = {52}, number = {22}, pages = {13306-13313}, doi = {10.1021/acs.est.8b03997}, pmid = {30354082}, issn = {1520-5851}, mesh = {Biofilms ; *Imaging, Three-Dimensional ; Microscopy, Electron, Scanning ; *Plastics ; X-Ray Microtomography ; X-Rays ; }, abstract = {Biofilm-sediment aggregate (BSA) contains a high water content, either within internal pores and channels or bound by extracellular polymeric substances (EPS) forming a highly hydrated biofilm matrix. Desiccation of BSAs alters the biofilm morphology and thus the physical characteristics of porous media, such as the binding matrix within BSA and internal pore geometry. Observing BSAs in their naturally hydrated form is essential but hampered due to the lack of techniques for imaging and discerning hydrated materials. Generally, imagery techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam nanotomography (FIB-nt)) involve the desiccation of BSAs (freeze-drying or acetone dehydration) or prevent differentiation between BSA components such as inorganic particles and pore water (confocal laser scanning microscopic (CLSM)). Here, we propose a novel methodology that simultaneously achieves the 3D visualization and quantification of BSAs and their components in their hydrated form at a submicron resolution using X-ray microcomputed tomography (μ-CT). It enables the high-resolution detection of comparable morphology of multiphase components within a hydrated aggregate: each single inorganic particle and the hydrated biofilm matrix. This allows the estimation of aggregate density and the illustration of biofilm-sediment binding matrix. This information provides valuable insights into investigations of the transport of BSAs and aggregate-associated sediment particles, contaminants (such as microplastics), organic carbon, and their impacts on aquatic biogeochemical cycling.}, } @article {pmid30352435, year = {2019}, author = {Wijesinghe, G and Dilhari, A and Gayani, B and Kottegoda, N and Samaranayake, L and Weerasekera, M}, title = {Influence of Laboratory Culture Media on in vitro Growth, Adhesion, and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus.}, journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre}, volume = {28}, number = {1}, pages = {28-35}, pmid = {30352435}, issn = {1423-0151}, mesh = {Biofilms/*growth & development ; *Culture Media ; Humans ; Microbiological Techniques/methods ; Pseudomonas aeruginosa/*growth & development ; Staphylococcus aureus/*growth & development ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa and Staphylococcus aureus dual-species biofilm infections are notoriously difficult to manage. This study aimed at investigating the influence of four different culture media on the planktonic growth, adhesion, and biofilm formation of P. aeruginosa and S. aureus.

MATERIALS AND METHODS: We monitored four different culture media including Nutrient Broth, Brain Heart Infusion (BHI) broth, Luria-Bertani broth, and RPMI 1640 medium on the planktonic growth, adhesion, and biofilm formation of P. aeruginosa (ATCC 27853) and S. aureus (ATCC 25923) using MTT assay and scanning electron microscopy (SEM).

RESULTS: The most robust growth of the mono- and dual-species cultures was noted in BHI broth. On the contrary, RPMI 1640 medium promoted maximal initial adhesion of both the mono- and dual-species, but BHI broth fostered the maximal biofilm growth. SEM images showed profuse extracellular polysaccharide production in biofilms, particularly in coculture, in BHI medium.

CONCLUSION: Our data demonstrate that BHI broth, relative to the other tested media, is the most conducive for in vitro evaluation of biofilm and planktonic growth kinetics of these two pathogens, both in mono- and coculture.}, } @article {pmid30352266, year = {2019}, author = {Muthuraman, MS and Nithya, S and Vinoth Kumar, V and Christena, LR and Vadivel, V and Subramanian, NS and Anthony, SP}, title = {Green synthesis of silver nanoparticles using Nardostachys jatamansi and evaluation of its anti-biofilm effect against classical colonizers.}, journal = {Microbial pathogenesis}, volume = {126}, number = {}, pages = {1-5}, doi = {10.1016/j.micpath.2018.10.024}, pmid = {30352266}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Anti-Inflammatory Agents ; Antioxidants ; Biofilms/*drug effects ; Green Chemistry Technology/*methods ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Nardostachys/*metabolism ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry ; Spectrometry, X-Ray Emission ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/drug effects ; }, abstract = {In this communication, we present the green synthesis of silver nanoparticles (AgNPs) using medicinally important Nardostachys jatamansi rhizome extract in the presence of sunlight. UV-vis spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and Energy dispersive X-ray analysis (EDX) were employed to characterize the synthesized AgNPs. UV-visible spectroscopic studies confirmed the presence of biosynthesized AgNPs. Transmission Electron Microscopic studies revealed the structure of spherical AgNPs in the diameter range of 10-15 nm. Energy dispersive X-ray analysis and elemental mapping clearly confirmed the presence of silver in AgNPs samples. Interestingly, biomolecules functionalised AgNPs exhibited a remarkable antioxidant, anti-inflammatory, and anti-biofilm activities and hence biosynthesized AgNPs from N. jatamansi can be used as a promising biomaterial for biomedical applications.}, } @article {pmid30351033, year = {2018}, author = {Aggarwal, S and Gomez-Smith, CK and Jeon, Y and LaPara, TM and Waak, MB and Hozalski, RM}, title = {Effects of Chloramine and Coupon Material on Biofilm Abundance and Community Composition in Bench-Scale Simulated Water Distribution Systems and Comparison with Full-Scale Water Mains.}, journal = {Environmental science & technology}, volume = {52}, number = {22}, pages = {13077-13088}, doi = {10.1021/acs.est.8b02607}, pmid = {30351033}, issn = {1520-5851}, mesh = {Biofilms ; *Chloramines ; *Drinking Water ; Water Microbiology ; Water Quality ; Water Supply ; }, abstract = {The vast majority of bacteria in drinking water distribution systems (DWDSs) reside in biofilms on the interior walls of water mains. Little is known about how water quality conditions affect water-main biofilms because of the inherent limitations in experimenting with drinking water supplies and accessing the water mains for sampling. Bench-scale reactors permit experimentation and ease of biofilm sampling, yet questions remain as to how well biofilms in laboratory reactors represent those on water mains. In this study, the effects of DWDS pipe materials and chloramine residual on biofilms were investigated by cultivating biofilms on cement, polyvinyl chloride, and high density polyethylene coupons in CDC reactors for up to 28 months in the presence of chloraminated or dechlorinated tap water. The bench-scale biofilm microbiomes were then compared with the microbiome on a water main from the full-scale system that supplied the water to the reactors. The presence of a chloramine residual (1.74 ± 0.21 mg/L) suppressed biofilm accumulation and selected for Mycobacterium-like and Sphingopyxis-like operational taxonomic units (OTUs) while the destruction of the chloramine residual resulted in a significant increase in biomass quantity and a shift toward a more diverse community dominated by Nitrospira-like OTUs, which, our results suggest, may be complete ammonia oxidizers (comammox). Coupon material, however, had a relatively minor effect on the abundance and community composition of the biofilm bacteria. Although biofilm communities from the chloraminated water reactor and the water mains shared some dominant populations (namely, Mycobacterium- and Nitrosomonas-like OTUs), the communities were significantly different. This manuscript provides novel insights into the effects of dechlorination and pipe material on biofilm community composition. Furthermore, to our knowledge, it is the first study to compare biofilm in a tap water-fed, bench-scale simulated distribution system to biofilm on water mains from the full-scale system supplying the tap water.}, } @article {pmid30350807, year = {2018}, author = {Nirwati, H and Hakim, MS and Darma, S and Mustafa, M and Nuryastuti, T}, title = {Detection of blaoxa genes and identification of biofilm-producing capacity of Acinetobacter baumannii in a tertiary teaching hospital, Klaten, Indonesia.}, journal = {The Medical journal of Malaysia}, volume = {73}, number = {5}, pages = {291-296}, pmid = {30350807}, issn = {0300-5283}, mesh = {Acinetobacter Infections/genetics/*microbiology ; Acinetobacter baumannii/*genetics ; Adolescent ; Adult ; Aged ; Biofilms/*growth & development ; Child ; Child, Preschool ; Cross Infection/genetics/*microbiology ; Drug Resistance, Bacterial/genetics ; Female ; Genes, Bacterial/*genetics ; Hospitals, Teaching ; Humans ; Indonesia ; Infant ; Infant, Newborn ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Polymerase Chain Reaction ; Tertiary Care Centers ; Young Adult ; beta-Lactamases/*genetics ; }, abstract = {INTRODUCTION: Acinetobacter baumannii (A. baumannii) is commonly found as an agent of nosocomial infections and demonstrates a high antibiotic resistance due to its carbapenemase production. The objectives of this study were to explore the antibiotic resistance pattern, the presence of OXAs genes and the biofilm-producing capacity of A. baumannii isolated from clinical specimens.

METHODS: Antibiotics susceptibility testing, detection of OXAs genes and the biofilm-producing capacity were performed using the Kirby Bauer method, polymerase chain reaction (PCR) and adherence quantitative assays, respectively.

RESULTS: A total of 80 A. baumannii isolates were mainly obtained from sputum and most of them were resistant to antibiotics. All A. baumannii carried blaOXA-51 gene, yet no blaOXA-24 and blaOXA-58 genes were detected. Fourteen (82.4%) of the 17 meropenem resistant isolates carried blaOXA-23 gene, but it was not found in meropenem sensitive isolates. In addition, sixty (75.0%) of 80 isolates were biofilm producers with 2 (2.5%), 16 (20.0%), and 42 (52.5%) isolates were identified as strong, moderate and weak biofilm producers, respectively.

CONCLUSION: Most of A. baumannii isolates had a high level of antibiotic resistance and had a capacity to produce biofilm.}, } @article {pmid30350577, year = {2018}, author = {Nikitina, AA and Ulasevich, SA and Kassirov, IS and Bryushkova, EA and Koshel, EI and Skorb, EV}, title = {Nanostructured Layer-by-Layer Polyelectrolyte Containers to Switch Biofilm Fluorescence.}, journal = {Bioconjugate chemistry}, volume = {29}, number = {11}, pages = {3793-3799}, doi = {10.1021/acs.bioconjchem.8b00648}, pmid = {30350577}, issn = {1520-4812}, mesh = {Arabinose/*administration & dosage/metabolism ; *Biofilms ; Drug Carriers/chemistry ; Escherichia coli/*physiology ; Fluorescence ; Humans ; Luminescence ; Metal Nanoparticles/chemistry ; Nanostructures/*chemistry ; Polyelectrolytes/*chemistry ; Silver/*chemistry ; Titanium/*chemistry ; }, abstract = {The development of stimuli-responsive nanocontainers is an issue of utmost importance for many applications such as targeted drug delivery, regulation of the cell and tissue behavior, making bacteria have useful functions and here converting light. The present work shows a new contribution to the design of polyelectrolyte (PE) containers based on surface modified mesoporous titania particles with deposited Ag nanoparticles to achieve chemical light upconversion via biofilms. The PE shell allows slowing down the kinetics of a release of loaded l-arabinose and switching the bacteria luminescence in a certain time. The hybrid TiO2/Ag/PE containers activated at 980 nm (IR) illumination demonstrate 10 times faster release of l-arabinose as opposed to non-activated containers. Fast IR-released l-arabinose switch bacteria fluorescence which we monitor at 510 nm. The approach described herein can be used in many applications where the target and delayed switching and light upconversion are required.}, } @article {pmid30347894, year = {2018}, author = {Cavallaro, G and Lazzara, G and Lisuzzo, L and Milioto, S and Parisi, F}, title = {Filling of Mater-Bi with Nanoclays to Enhance the Biofilm Rigidity.}, journal = {Journal of functional biomaterials}, volume = {9}, number = {4}, pages = {}, pmid = {30347894}, issn = {2079-4983}, abstract = {We investigated the efficacy of several nanoclays (halloysite, sepiolite and laponite) as nanofillers for Mater-Bi, which is a commercial bioplastic extensively used within food packaging applications. The preparation of Mater-Bi/nanoclay nanocomposite films was easily achieved by means of the solvent casting method from dichloroethane. The prepared bio-nanocomposites were characterized by dynamic mechanical analysis (DMA) in order to explore the effect of the addition of the nanoclays on the mechanical behavior of the Mater-Bi-based films. Tensile tests found that filling Mater-Bi with halloysite induced the most significant improvement of the mechanical performances under traction force, while DMA measurements under the oscillatory regime showed that the polymer glass transition was not affected by the addition of the nanoclay. The tensile properties of the Mater-Bi/halloysite nanotube (HNT) films were competitive compared to those of traditional petroleum plastics in terms of the elastic modulus and stress at the breaking point. Both the mechanical response to the temperature and the tensile properties make the bio-nanocomposites appropriate for food packaging and smart coating purposes. Here, we report a preliminary study of the development of sustainable hybrid materials that could be employed in numerous industrial and technological applications within materials science and pharmaceutics.}, } @article {pmid30347401, year = {2019}, author = {Yamada, KJ and Kielian, T}, title = {Biofilm-Leukocyte Cross-Talk: Impact on Immune Polarization and Immunometabolism.}, journal = {Journal of innate immunity}, volume = {11}, number = {3}, pages = {280-288}, pmid = {30347401}, issn = {1662-8128}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Infections/*immunology ; *Biofilms ; Extracellular Matrix/physiology ; *Host Microbial Interactions ; Humans ; Immune Evasion ; Immunity, Innate ; Leukocytes/*physiology ; Macrophages/metabolism ; Neutrophils/metabolism ; Plankton/immunology ; Receptors, Pattern Recognition/physiology ; }, abstract = {Biofilms are bacterial communities contained within an extracellular matrix, which can colonize both native tissues and artificial surfaces. In particular, indwelling medical devices and prosthetic implants are targets for biofilm formation because they facilitate bacterial attachment via host proteins that coat the foreign body. Biofilm infections are particularly challenging to treat, since they are not readily cleared by antibiotics, require invasive procedures to eradicate, and are prone to recurrence. It has been demonstrated that biofilm-derived products can actively suppress proinflammatory immune responses, as evident by the recruitment of myeloid-derived suppressor cells and macrophage (MФ) polarization towards an anti-inflammatory state. Recent studies have shown that alterations in leukocyte metabolism shape their inflammatory phenotype and function. For example, anti-inflammatory MФs are biased towards oxidative phosphorylation whereas proinflammatory MФs favor aerobic glycolysis. This review will compare the immune responses elicited by planktonic and biofilm bacterial infections, with a discussion on the metabolic properties of MФs and neutrophils in response to both bacterial growth conditions.}, } @article {pmid30347328, year = {2019}, author = {Parrino, B and Schillaci, D and Carnevale, I and Giovannetti, E and Diana, P and Cirrincione, G and Cascioferro, S}, title = {Synthetic small molecules as anti-biofilm agents in the struggle against antibiotic resistance.}, journal = {European journal of medicinal chemistry}, volume = {161}, number = {}, pages = {154-178}, doi = {10.1016/j.ejmech.2018.10.036}, pmid = {30347328}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Drug Resistance, Microbial/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Small Molecule Libraries/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Biofilm formation significantly contributes to microbial survival in hostile environments and it is currently considered a key virulence factor for pathogens responsible for serious chronic infections. In the last decade many efforts have been made to identify new agents able to modulate bacterial biofilm life cycle, and many compounds have shown interesting activities in inhibiting biofilm formation or in dispersing pre-formed biofilms. However, only a few of these compounds were tested using in vivo models for their clinical significance. Contrary to conventional antibiotics, most of the anti-biofilm compounds act as anti-virulence agents as they do not affect bacterial growth. In this review we selected the most relevant literature of the last decade, focusing on the development of synthetic small molecules able to prevent bacterial biofilm formation or to eradicate pre-existing biofilms of clinically relevant Gram-positive and Gram-negative pathogens. In addition, we provide a comprehensive list of the possible targets to counteract biofilm formation and development, as well as a detailed discussion the advantages and disadvantages of the different current biofilm-targeting strategies.}, } @article {pmid30345922, year = {2018}, author = {Ciulla, M and Di Stefano, A and Marinelli, L and Cacciatore, I and Di Biase, G}, title = {RNAIII Inhibiting Peptide (RIP) and Derivatives as Potential Tools for the Treatment of S. aureus Biofilm Infections.}, journal = {Current topics in medicinal chemistry}, volume = {18}, number = {24}, pages = {2068-2079}, doi = {10.2174/1568026618666181022120711}, pmid = {30345922}, issn = {1873-4294}, mesh = {Animals ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; Oligopeptides/chemistry/*pharmacology ; RNA, Bacterial/*antagonists & inhibitors ; Staphylococcal Infections/*drug therapy/*microbiology ; Staphylococcus aureus/*drug effects/*enzymology/growth & development ; }, abstract = {S. aureus under the biofilm mode of growth is often related to several nosocomial infections, more frequently associated with indwelling medical devices (catheters, prostheses, portacaths or heart valves). As a biofilm, the biopolymer matrix provides an excellent growth medium, increasing the tolerance to antibiotics and host immune system. To date, the antimicrobial therapy alone is not effective. A novel strategy to prevent biofilm formation is based on the interference with the bacterial cell-cell communication, a process known as quorum sensing (QS) and mediated by the RNA-III-activating peptide (RAP) and its target protein TRAP (Target of RAP). The RNAIII inhibiting peptide (RIP) is able to inhibit S. aureus pathogenesis by disrupting QS mechanism competing with RAP, thus inhibiting the phosphorylation of TRAP. This alteration leads to a reduced adhesion and to the inhibition of RNAIII synthesis, with the subsequent suppression of toxins synthesis. The present paper will provide an overview on the activity and potential applications of RIP as biofilm inhibiting compound, useful in the management of S. aureus biofilm infections. Moreover, medicinal chemistry strategies have been examined to better understand which modifications and/or structure alterations were able to produce new derivatives of this QS inhibitor with an improved antibiofilm activity.}, } @article {pmid30345305, year = {2018}, author = {Alcántar-Curiel, MD and Ledezma-Escalante, CA and Jarillo-Quijada, MD and Gayosso-Vázquez, C and Morfín-Otero, R and Rodríguez-Noriega, E and Cedillo-Ramírez, ML and Santos-Preciado, JI and Girón, JA}, title = {Association of Antibiotic Resistance, Cell Adherence, and Biofilm Production with the Endemicity of Nosocomial Klebsiella pneumoniae.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {7012958}, pmid = {30345305}, issn = {2314-6141}, mesh = {*Bacterial Adhesion ; *Biofilms ; Cross Infection/microbiology ; *Drug Resistance, Bacterial ; Humans ; Klebsiella pneumoniae/*isolation & purification/*physiology ; Mexico ; Tertiary Care Centers ; }, abstract = {Klebsiella pneumoniae is a leading cause of multiple nosocomial infections, some of which are associated with high mortality. The increasing prevalence of antibiotic-resistant strains highlights their clinical importance and how complicated managing treatment can be. In this study, we investigated antimicrobial resistance, cell adherence, and biofilm production of nosocomial K. pneumoniae strains isolated from surveillance studies in a Mexican tertiary hospital and evaluated the potential association of these phenotypes with endemicity. The great majority of the clones exhibited adhesion to cultured epithelial cells and were strong biofilm producers. A direct relationship between adhesion phenotypes, biofilm production, and endemicity was not always apparent. Biofilm formation and production of ESBL did not appear to be directly associated. Notably, all the endemic strains were multidrug-resistant. This study emphasizes that while endemic strains possess various virulence-associated properties, antimicrobial resistance appears to be a determining factor of their endemicity.}, } @article {pmid30342101, year = {2018}, author = {Vt, A and Paramanantham, P and Sb, SL and Sharan, A and Alsaedi, MH and Dawoud, TMS and Asad, S and Busi, S}, title = {Antimicrobial photodynamic activity of rose bengal conjugated multi walled carbon nanotubes against planktonic cells and biofilm of Escherichia coli.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {300-310}, doi = {10.1016/j.pdpdt.2018.10.013}, pmid = {30342101}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Escherichia coli/*drug effects ; Lasers, Semiconductor ; Nanotubes, Carbon/chemistry ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Plankton/*drug effects/microbiology ; Reactive Oxygen Species/metabolism ; Rose Bengal/administration & dosage/*pharmacology ; }, abstract = {BACKGROUND: The global threat of antimicrobial resistance especially due to the bacterial biofilms has engaged researchers in the search of new treatment modalities. Antimicrobial photodynamic inactivation (aPDI) is one of the alternative treatment modalities which kills bacteria by generating endogenous reactive oxygen species (ROS). In this work authors evaluated the antibacterial and antibiofilm efficacy of rose Bengal (RB) conjugated to CNT against E. coli.

METHODS: The interaction of anionic dye to the CNT was studied using UV-vis spectroscopy, HRTEM, FTIR and spectrofluorometry. Phototoxicity of RBCNT conjugate against E. coli was studied using a green light of 50 mW and radiant exposure of 1674.7 J/ cm[2] for 10 min. The antibiofilm activity and mechanism of action of RBCNT conjugate in presence of light was evaluated.

RESULTS: The loading and encapsulation was found to be 15.46 ± 1.05 and 61.85 ± 4.23% respectively. The photodynamic inactivation of planktonic cells of E. coli was found to 5.46 and 3.56 log10 CFU/ml reduction on treatment with RBCNT and RB respectively. The conjugate also exhibited efficient and enhanced antibiofilm activity against E. coli. The study of mechanism of action has confirmed cell membrane and DNA damage were the two main targets of aPDI.

CONCLUSION: This report has concluded the efficient photodynamic inactivation occurred in Gram negative bacteria E. coli due to the increased production of ROS inside the bacterial cells. Hence, the newly synthesized RBCNT conjugate can be efficiently utilized to control infections caused by E. coli.}, } @article {pmid30341934, year = {2019}, author = {Allyn, G and Bloebaum, RD and Epperson, RT and Nielsen, MB and Dodd, KA and Williams, DL}, title = {Ability of a wash regimen to remove biofilm from the exposed surface of materials used in osseointegrated implants.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {37}, number = {1}, pages = {248-257}, doi = {10.1002/jor.24161}, pmid = {30341934}, issn = {1554-527X}, support = {1I01RX001198-01A2//George E. Wahlen Department of Veterans Affairs/International ; 1I01RX002287-01//George E. Wahlen Department of Veterans Affairs/International ; //DJO Surgical/International ; HU0001-11-1-0004//Center for Rehabilitation Science Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University/International ; HU0001-15-2-0003//Center for Rehabilitation Science Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University/International ; }, mesh = {Alloys ; *Biofilms ; Bone-Anchored Prosthesis/*microbiology ; Disinfection/*methods ; Microscopy, Electron, Scanning ; Niobium/*therapeutic use ; Prosthesis-Related Infections/*prevention & control ; Titanium/*therapeutic use ; }, abstract = {The skin/implant interface of osseointegrated (OI) implants is susceptible to infection, causing excess pain, increased morbidity, and possibly implant removal. Novel distal femoral OI implants with binary nitride coatings have been developed with little physiological modeling to collect microbiological evidence of resistance to bacterial attachment. This in vitro study evaluated a Ti-6Al-4V alloy coated with TiNbN and treated with low plasticity burnishing (LPB) to assess attachment and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) under physiologically modeling conditions compared to standard Ti-6Al-4V alloy materials with a polished ("Color Buff") or non-polished finish ("Satin Finish"). Washability of the materials were also assessed and compared. It was hypothesized that the TiNbN/LPB treatments would resist bacterial adhesion and biofilm formation to a greater degree than the other two materials, and have a higher degree of bacterial removal following a clinically relevant wash regimen. Material types were exposed to a constant flow of broth containing MRSA and were analyzed using bacterial quantification, surface coverage analysis, and SEM imaging. Quantification data showed no difference in bacterial attachment among the varying material types both with and without the wash regimen. Surface coverage and SEM analysis confirmed results. The wash regimen led to an approximately 3 log10 reduction in bacteria for all material types. Though the results did not support the hypothesis that a TiNbN coating/LPB treatment might resist bacterial attachment/biofilm formation more than other alloys, or have less bacteria after cleaning, results did support the potential importance of a daily wound-hygiene regimen at the skin/implant interface of OI materials. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.}, } @article {pmid30341079, year = {2018}, author = {Jiang, W and Wang, Y and Luo, J and Li, X and Zhou, X and Li, W and Zhang, L}, title = {Effects of Antimicrobial Peptide GH12 on the Cariogenic Properties and Composition of a Cariogenic Multispecies Biofilm.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {24}, pages = {}, pmid = {30341079}, issn = {1098-5336}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cariogenic Agents/*pharmacology ; Dental Caries/microbiology ; Dental Plaque/microbiology ; Humans ; Hydrogen Peroxide/metabolism ; Lactic Acid/metabolism ; Microbial Sensitivity Tests ; Microbiota/drug effects ; Peptides/*pharmacology ; Streptococcus gordonii/drug effects/growth & development ; Streptococcus mutans/drug effects/growth & development ; Streptococcus sanguis/drug effects/growth & development ; }, abstract = {Dental caries is a biofilm-mediated disease that occurs when acidogenic/aciduric bacteria obtain an ecological advantage over commensal species. In previous studies, the effects of the antimicrobial peptide GH12 on planktonic bacteria and monospecies biofilms were confirmed. The objectives of this study were to investigate the effects of GH12 on a cariogenic multispecies biofilm and to preliminarily explain the mechanism. In this biofilm model, Streptococcus mutans ATCC 70061 was the representative of cariogenic bacteria, while Streptococcus gordonii ATCC 35105 and Streptococcus sanguinis JCM 5708 were selected as healthy microbiota. The results showed that GH12 was more effective in suppressing S. mutans than the other two species, with lower MIC and minimal bactericidal concentration (MBC) values among diverse type strains and clinical isolated strains. Therefore, GH12, at no more than 8 mg/liter, was used to selectively suppress S. mutans in the multispecies biofilm. GH12 at 4 mg/liter and 8 mg/liter reduced the cariogenic properties of the multispecies biofilm in biofilm formation, glucan synthesis, and lactic acid production. In addition, GH12 suppressed S. mutans within the multispecies biofilm and changed the bacterial composition. Furthermore, 8 mg/liter GH12 showed a selective bactericidal impact on S. mutans, and GH12 promoted hydrogen peroxide production in S. sanguinis and S. gordonii, which improved their ecological advantages. In conclusion, GH12 inhibited the cariogenic properties and changed the composition of the multispecies biofilm through a two-part mechanism by which GH12 directly suppressed the growth of S. mutans as well as enhanced the ecological competitiveness of S. sanguinis and S. gordoniiIMPORTANCE Dental caries is one of the most prevalent chronic infectious diseases worldwide, with substantial economic and quality-of-life impacts. Streptococcus mutans has been considered the principal pathogen of dental caries. To combat dental caries, an antimicrobial peptide, GH12, was designed, and its antibacterial effects on planktonic S. mutans and the monospecies biofilm were confirmed. As etiological concepts of dental caries evolved to include microecosystems, the homeostasis between pathogenic and commensal bacteria and a selective action on cariogenic virulence have increasingly become the focus. The novelty of this research was to study the effects of the antimicrobial peptides on a controlled cariogenic multispecies biofilm model. Notably, the role of an antimicrobial agent in regulating interspecific competition and composition shifts within this multispecies biofilm was investigated. With promising antibacterial and antibiofilm properties, the use of GH12 might be of importance in preventing and controlling caries and other dental infections.}, } @article {pmid30340133, year = {2019}, author = {Spennati, F and Mora, M and Tigini, V and La China, S and Di Gregorio, S and Gabriel, D and Munz, G}, title = {Removal of Quebracho and Tara tannins in fungal bioreactors: Performance and biofilm stability analysis.}, journal = {Journal of environmental management}, volume = {231}, number = {}, pages = {137-145}, doi = {10.1016/j.jenvman.2018.10.001}, pmid = {30340133}, issn = {1095-8630}, mesh = {Biofilms ; *Bioreactors ; Fungi ; *Tannins ; Wastewater ; }, abstract = {Tannins are polyphenolic compounds produced by plants that are used in the vegetable tanning of leather at industrial scale. Quebracho tannin and Tara tannin are intensively used by the tanning industry and are two of the most recalcitrant compounds that can be found in tannery wastewaters. In this study two reactors fed with Quebracho tannin and Tara tannin, respectively, were inoculated with polyurethane foam cubes colonized with a fungal strain biofilm of Aspergillus tubingensis MUT 990. A stable biofilm was maintained in the reactor fed with Quebracho tannin during 180 days of operation. Instead, biofilm got detached from the foam cubes during the start-up of the reactor fed with Tara tannin and a bacterial-based suspended culture was developed and preserved along the operational period (226 days). Soluble chemical oxygen demand removals up to 53% and 90% and maximum elimination capacities of 9.1 g sCOD m[-3] h[-1] and 37.9 g sCOD m[-3] h[-1] of Quebracho and Tara tannins, respectively, were achieved in the reactors without the addition of co-substrates. Next generation sequencing analysis for bacteria and fungi showed that a fungal consortium was developed in the reactor fed with Quebracho tannin while fungi were outcompeted by bacteria in the reactor fed with Tara tannin. Furthermore, Quebracho and Tara tannins were successfully co-treated in a single reactor where both fungi and bacteria were preserved.}, } @article {pmid30339767, year = {2019}, author = {Farfán, M and Lártiga, N and Benavides, MB and Alegría-Morán, R and Sáenz, L and Salcedo, C and Lapierre, L}, title = {Capacity to adhere to and invade human epithelial cells, as related to the presence of virulence genes in, motility of, and biofilm formation of Campylobacter jejuni strains isolated from chicken and cattle.}, journal = {Canadian journal of microbiology}, volume = {65}, number = {2}, pages = {126-134}, doi = {10.1139/cjm-2018-0503}, pmid = {30339767}, issn = {1480-3275}, mesh = {Animals ; *Bacterial Adhesion/genetics ; *Biofilms ; Campylobacter jejuni/genetics/isolation & purification/*physiology ; Cattle ; Cells, Cultured ; Chickens ; Epithelial Cells/microbiology ; Humans ; Virulence/genetics ; }, abstract = {Campylobacter jejuni is a zoonotic pathogen transmitted through the "farm to fork" route. Outbreaks are generally associated with the consumption of chicken meat; however, dairy cows, birds, wild and domestic food animals, and pets are other important sources. Currently, there are not enough data comparing the virulence of strains isolated from these reservoirs. In this study, we compared C. jejuni strains isolated from broiler chickens and dairy cattle by determining their ability to adhere to and invade in vitro human colonic epithelial cells in the T84 cell line with their motility, formation of biofilms, and presence of eight virulence genes. A Wilcoxon Rank Sum test was performed to establish the relationship between presence of the studied genes and cellular invasion and adhesion, as well as differences between the animal species of origin of the isolate. A Spearman correlation was performed to assess the relationship between invasion and motility, along with invasion and biofilm generation. The virB11 gene was positively associated with the adherence capacity of the strains (mean difference = 0.21, p = 0.006), and strains isolated from chickens showed a significant difference for adherence compared with strains isolated from cattle (p = 0.0001). Our results indicate that strains of C. jejuni have a difference in their adherence capacity depending on the animal reservoir from which they came, with chicken isolates displaying higher virulence than dairy cattle isolates.}, } @article {pmid30338995, year = {2018}, author = {Swasthi, HM and Bhasne, K and Mahapatra, S and Mukhopadhyay, S}, title = {Human Fibrinogen Inhibits Amyloid Assembly of Biofilm-Forming CsgA.}, journal = {Biochemistry}, volume = {57}, number = {44}, pages = {6270-6273}, doi = {10.1021/acs.biochem.8b00841}, pmid = {30338995}, issn = {1520-4995}, mesh = {Amino Acid Sequence ; Amyloid/*antagonists & inhibitors ; Biofilms/*growth & development ; Escherichia coli/metabolism ; Escherichia coli Proteins/*metabolism ; Fibrinogen/*pharmacology ; Humans ; Protein Binding ; Protein Conformation ; Protein Multimerization/*drug effects ; }, abstract = {Curli is a biofilm-forming amyloid that is expressed on the surface of Gram-negative enteric bacteria such as Escherichia coli and Salmonella spp. Curli is primarily composed of the major structural subunit, CsgA, and interacts with a wide range of human proteins that contribute to bacterial virulence. The adsorption of curli onto the contact-phase proteins and fibrinogen results in a hypocoagulatory state. Using an array of biochemical and biophysical tools, we elucidated the molecular mechanism of interaction between human fibrinogen and CsgA. Our results revealed that a substoichiometric concentration of fibrinogen delays the onset of CsgA aggregation by inhibiting the early events of CsgA assembly. The presence of fibrinogen prevents the maturation of CsgA into fibrils and maintains the soluble state of CsgA. We also demonstrate that fibrinogen interacts more effectively with the disordered conformational state of CsgA than with the ordered β-rich state. Our study suggested that fibrinogen is an anti-curli protein and that the interplay of CsgA and fibrinogen might be a host defense mechanism against curli biogenesis, biofilm formation, bacterial colonization, and infection.}, } @article {pmid30338681, year = {2018}, author = {Dua, K and Gupta, G and Koteswara Rao, N and Bebawy, M}, title = {Nano-antibiotics: a novel approach in treating P. aeruginosa biofilm infections.}, journal = {Minerva medica}, volume = {109}, number = {5}, pages = {400}, doi = {10.23736/S0026-4806.18.05588-X}, pmid = {30338681}, issn = {1827-1669}, mesh = {Anti-Bacterial Agents/*administration & dosage/pharmacology/therapeutic use ; Biofilms/*drug effects ; Combined Modality Therapy ; Humans ; Magnetic Field Therapy ; Nanocapsules ; Nanoparticles/*administration & dosage ; Polymers ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Ultrasonic Therapy ; }, } @article {pmid30337708, year = {2019}, author = {Ch'ng, JH and Chong, KKL and Lam, LN and Wong, JJ and Kline, KA}, title = {Biofilm-associated infection by enterococci.}, journal = {Nature reviews. Microbiology}, volume = {17}, number = {2}, pages = {82-94}, pmid = {30337708}, issn = {1740-1534}, support = {R21 AI126023/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial ; Enterococcus/*physiology ; Gram-Positive Bacterial Infections/drug therapy/microbiology ; *Host Microbial Interactions ; Humans ; Urinary Tract Infections/drug therapy/microbiology ; }, abstract = {Enterococci are ubiquitous members of the human gut microbiota and frequent causes of biofilm-associated opportunistic infections. Enterococci cause 25% of all catheter-associated urinary tract infections, are frequently isolated in wounds and are increasingly found in infective endocarditis, and all of these infections are associated with biofilms. Enterococcal biofilms are intrinsically tolerant to antimicrobials and thus are a serious impediment for treating infections. In this Review, we describe the spatiotemporal development of enterococcal biofilms and the factors that promote or inhibit biofilm formation. We discuss how the environment, including the host and other co-colonizing microorganisms, affects biofilm development. Finally, we provide an overview of current and future interventions to limit enterococcal biofilm-associated infections. Overall, enterococcal biofilms remain a pressing clinical problem, and there is an urgent need to better understand their development and persistence and to identify novel treatments.}, } @article {pmid30337052, year = {2018}, author = {Kirstein, IV and Wichels, A and Krohne, G and Gerdts, G}, title = {Mature biofilm communities on synthetic polymers in seawater - Specific or general?.}, journal = {Marine environmental research}, volume = {142}, number = {}, pages = {147-154}, doi = {10.1016/j.marenvres.2018.09.028}, pmid = {30337052}, issn = {1879-0291}, mesh = {Bacteria/classification/genetics ; *Bacterial Physiological Phenomena ; *Biofilms ; Microbiota/genetics/*physiology ; *Polymers ; RNA, Ribosomal, 16S/genetics ; RNA, Ribosomal, 18S/genetics ; Seawater/*microbiology ; }, abstract = {To understand the ecological impacts of the "Plastisphere", those microbes need to be identified that preferentially colonize and interact with synthetic polymer surfaces, as opposed to general surface colonizers. It was hypothesized that the microbial biofilm composition varies distinctly between different substrates. A long-term incubation experiment was conducted (15month) with nine different synthetic polymer films as substrate as well as glass using a natural seawater flow-through system. To identify colonizing microorganisms, 16S and 18SrRNA gene tag sequencing was performed. The microbial biofilms of these diverse artificial surfaces were visualized via scanning electron microscopy. Biofilm communities attached to synthetic polymers are distinct from glass associated biofilms; apparently a more general marine biofilm core community serves as shared core among all synthetic polymers rather than a specific synthetic polymer community. Nevertheless, characteristic and discriminatory taxa of significantly different biofilm communities were identified, indicating their specificity to a given substrate.}, } @article {pmid30336397, year = {2019}, author = {Saunders, LP and Bischoff, KM and Bowman, MJ and Leathers, TD}, title = {Inhibition of Lactobacillus biofilm growth in fuel ethanol fermentations by Bacillus.}, journal = {Bioresource technology}, volume = {272}, number = {}, pages = {156-161}, doi = {10.1016/j.biortech.2018.10.016}, pmid = {30336397}, issn = {1873-2976}, mesh = {Bacillus/*metabolism ; Biofilms/*drug effects ; Ethanol/*metabolism ; *Fermentation ; Lactobacillus/drug effects/*physiology ; Lipopeptides/pharmacology ; Saccharomyces cerevisiae/drug effects ; }, abstract = {Commercial fuel ethanol fermentations suffer from microbial contaminants, particularly species of Lactobacillus that may persist as antibiotic-resistant biofilms. In this study, culture supernatants from 54 strains of Bacillus known to produce lipopeptides were tested for inhibition of biofilm formation by Lactobacillus fermentum, L. plantarum, and L. brevis strains previously isolated as biofilm-forming contaminants of a commercial fuel ethanol facility. Eleven Bacillus strains inhibited biofilm formation by all three strains by at least 65% of controls. None of these strains inhibited Saccharomyces cerevisiae. Three strains also significantly inhibited planktonic cultures of Lactobacillus. Culture supernatants from B. nakamurai strain NRRL B-41091 were particularly effective. Inhibition was bacteriostatic rather than bacteriocidal, and appeared to be specific for strains of Lactobacillus. Furthermore, the inhibitor from B. nakamurai was shown to prevent stuck fermentations in a corn mash model fermentation system of S. cerevisiae contaminated with L. fermentum.}, } @article {pmid30336067, year = {2019}, author = {Shelud'ko, AV and Filip'echeva, YA and Telesheva, EM and Yevstigneyeva, SS and Petrova, LP and Katsy, EI}, title = {Restoration of polar-flagellum motility and biofilm-forming capacity in the mmsB1 mutant of the alphaproteobacterium Azospirillum brasilense Sp245 points to a new role for a homologue of 3-hydroxyisobutyrate dehydrogenase.}, journal = {Canadian journal of microbiology}, volume = {65}, number = {2}, pages = {144-154}, doi = {10.1139/cjm-2018-0481}, pmid = {30336067}, issn = {1480-3275}, mesh = {Alcohol Oxidoreductases/*physiology ; Azospirillum brasilense/*physiology ; *Biofilms ; Flagella/*physiology ; Hydrophobic and Hydrophilic Interactions ; }, abstract = {The bacterium Azospirillum brasilense can swim and swarm owing to the rotation of a constitutive polar flagellum (Fla) and inducible lateral flagella, respectively. They also form biofilms on various interfaces. Experimental data on flagellar assembly and social behaviours in these bacteria are scarce. Here, for the first time, the chromosomal coding sequence mmsB1 for a homologue of 3-hydroxyisobutyrate dehydrogenase (protein accession Nos. ADT80774 and E7CWE2) was shown to play a role in the assembly of motile Fla and in biofilm biomass accumulation. In the previously obtained mutant SK039 of A. brasilense Sp245, an Omegon-Km insertion in mmsB1 was concurrent with changes in cell-surface properties and with suppression of Fla assembly (partial) and Fla-dependent motility (complete). Here, the immotile leaky Fla[-] mutant SK039 was complemented with the expression vector pRK415-borne mmsB1 gene of Sp245. In the complemented mutant, the elevated relative cell hydrophobicity and changed relative membrane fluidity of SK039 returned to the wild-type levels; also, biofilm biomass accumulation increased and even reached Sp245's levels under nutritionally rich conditions. In strain SK039 (pRK415-mmsB1), the percentage of cells with Fla became significantly higher than that in mutant SK039, and the Fla-driven swimming velocity was equal to that in strain Sp245.}, } @article {pmid30335931, year = {2018}, author = {Liu, T and Guo, Z and Zeng, Z and Guo, N and Lei, Y and Liu, T and Sun, S and Chang, X and Yin, Y and Wang, X}, title = {Marine Bacteria Provide Lasting Anticorrosion Activity for Steel via Biofilm-Induced Mineralization.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {46}, pages = {40317-40327}, doi = {10.1021/acsami.8b14991}, pmid = {30335931}, issn = {1944-8252}, mesh = {*Biofilms ; Cellulose/chemistry ; Corrosion ; Electrochemistry ; Microscopy, Electron, Scanning ; Oceans and Seas ; Plasmids/metabolism ; Polymers/chemistry ; *Pseudoalteromonas ; Seawater/*microbiology ; Steel ; Temperature ; *Water Microbiology ; X-Ray Diffraction ; }, abstract = {Steel corrosion is a global problem in marine engineering. Numerous inhibitory treatments have been applied to mitigate the degradation of metallic materials; however, they typically have a high cost and are not environmental friendly. Here, we present a novel and "green" approach for the protection of steel by a marine bacterium Pseudoalteromonas lipolytica. This approach protects steel from corrosion in seawater via the formation of a biofilm followed by the formation of an organic-inorganic hybrid film. The hybrid film is composed of multiple layers of calcite and bacterial extracellular polymeric substances, exhibiting high and stable barrier protection efficiency and further providing an in situ self-healing activity. The process involving the key transition from biofilm to biomineralized film is essential for its lasting anticorrosion activity, which overcomes the instability of biofilm protection on corrosion. Therefore, this study introduces a new perspective and an option for anticorrosion control in marine environments.}, } @article {pmid30334338, year = {2018}, author = {Wang, J and Song, M and Pan, J and Shen, X and Liu, W and Zhang, X and Li, H and Deng, X}, title = {Quercetin impairs Streptococcus pneumoniae biofilm formation by inhibiting sortase A activity.}, journal = {Journal of cellular and molecular medicine}, volume = {22}, number = {12}, pages = {6228-6237}, pmid = {30334338}, issn = {1582-4934}, mesh = {Aminoacyltransferases/antagonists & inhibitors/*chemistry/genetics ; Bacterial Proteins/antagonists & inhibitors/*chemistry/genetics ; Biofilms ; Crystallography, X-Ray ; Cysteine Endopeptidases/*chemistry/genetics ; Humans ; Models, Molecular ; Pneumococcal Infections/*drug therapy/microbiology ; Quercetin/*chemistry ; Streptococcus pneumoniae/*chemistry/enzymology/pathogenicity ; }, abstract = {Biofilm formation mediated by sortase A (srtA) is important for bacterial colonisation and resistance to antibiotics. Thus, the inhibitor of SrtA may represent a promising agent for bacterial infection. The structure of Streptococcus pneumoniae D39 srtA has been characterised by crystallisation. Site-directed mutagenesis was used for the determination of the key residues for the activity of S. pneumoniae D39 srtA. An effective srtA inhibitor, quercetin, and its mechanism was further identified using srtA activity inhibition assay and molecular modelling. In this study, the crystal structure of S. pneumoniae D39 srtA has been solved and shown to contain a unique domain B. Additionally, its transpeptidase activity was evaluated in vitro. Based on the structure, we identified Cys207 as the catalytic residue, with His141 and Arg215 serving as binding sites for the peptide substrate. We found that quercetin can specifically compete with the natural substrate, leading to a significant decrease in the catalytic activity of this enzyme. In cells co-cultured with this small molecule inhibitor, NanA cannot anchor to the cell wall effectively, and biofilm formation and biomass decrease significantly. Interestingly, when we supplemented cultures with sialic acid, a crucial signal for pneumococcal coloniation and the invasion of the host in the co-culture system, biofilm loss did not occur. This result indicates that quercetin inhibits biofilm formation by affecting sialic acid production. In conclusion, the inhibition of pneumococcal srtA by the small molecule quercetin offers a novel strategy for pneumococcal preventative therapy.}, } @article {pmid30333962, year = {2018}, author = {Fang, H and Liu, L and Zhang, Y and Yang, H and Yan, Y and Ding, X and Han, Y and Zhou, D and Yang, R}, title = {BfvR, an AraC-Family Regulator, Controls Biofilm Formation and pH6 Antigen Production in Opposite Ways in Yersinia pestis Biovar Microtus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {347}, pmid = {30333962}, issn = {2235-2988}, mesh = {Animals ; Antigens, Bacterial/*metabolism ; Biofilms/*growth & development ; Caenorhabditis elegans/microbiology ; Cyclic GMP/analogs & derivatives/analysis ; Disease Models, Animal ; *Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Genes, Regulator ; Mice, Inbred BALB C ; Plague/microbiology/pathology ; Polysaccharides, Bacterial/metabolism ; Survival Analysis ; Transcription Factors/*metabolism ; Virulence ; Yersinia pestis/genetics/*growth & development/*metabolism ; }, abstract = {Biofilm formation is critical for blocking flea foregut and hence for transmission of Y. pestis by flea biting. In this study, we identified the regulatory role of the AraC-family transcriptional regulator BfvR (YPO1737 in strain CO92) in biofilm formation and virulence of Yersinia pestis biovar Microtus. Crystal violet staining, Caenorhabditis elegans biofilm assay, colony morphology assay, intracellular c-di-GMP concentration determination, and BALB/c mice challenge were employed to reveal that BfvR enhanced Y. pestis biofilm formation while repressed its virulence in mice. Further molecular biological assays demonstrated that BfvR directly stimulated the expression of hmsHFRS, waaAE-coaD, and hmsCDE, which, in turn, affected the production of exopolysaccharide, LPS, and c-di-GMP, respectively. In addition, BfvR directly and indirectly repressed psaABC and psaEF transcription, respectively. We concluded that the modulation of biofilm- and virulence-related genes by BfvR led to increased biofilm formation and reduced virulence of Y. pestis biovar Microtus.}, } @article {pmid30333795, year = {2018}, author = {Lawrence, JR and Winkler, M and Neu, TR}, title = {Multi-Parameter Laser Imaging Reveals Complex Microscale Biofilm Matrix in a Thick (4,000 μm) Aerobic Methanol Oxidizing Community.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2186}, pmid = {30333795}, issn = {1664-302X}, abstract = {Although methanol has frequently been used as an inexpensive supplementary carbon source to support treatment processes, knowledge of the resultant microbial biofilms, their 3D architecture, microenvironments, exopolymer chemistry and populations remains limited. We supplied methanol as a supplementary carbon source to biofilms developing in rotating annular reactors. Analysis of circulation waters (1.0 l d[-1]) indicated that dissolved organic carbon was reduced by 25%, NO3-nitrogen by 95%, and total phosphorus by 70%. Analyses of populations using culture based techniques and fluorescence in situ hybridization indicated enrichment of nitrifiers, denitrifiers, and methylotrophic bacteria relative to reference biofilms not receiving methanol. The biofilms that developed were up to 4,000 μm thick. Staining with fluor conjugated lectins in combination with nucleic acid stains, revealed the presence of discrete bacterial cells inside complex globular polymeric structures. These structures were in turn surrounded by an interstitial polymer containing a variety of bacterial cell types. The globular structures bound FITC-conjugated lectins, from Canavalia ensiformis and Ulex europeaus. The FITC-lectin of Phaseolus vulgaris bound the surface of the globular structures and more generally within the matrix. Chemical analyses of the polymer paralleled the results of lectin analyses indicating that the dominant neutral sugars were glucose, galactose, mannose, rhamnose, with fucose and ribose as minor constituents. Amino sugars were not detected. Dual channel imaging with pH sensitive probes indicated that pH gradients from pH 4 to 7 occurred across the globular microcolonies. Critically for the maintenance of aerobic conditions throughout the thick biofilm it was extensively penetrated by a fine fissure network revealed by the location of fluorescent latex microbeads as detected by confocal laser scanning microscopy. Microelectrode studies confirmed the absence of any detectable Eh gradients within the biofilm. However, mobility of various size-fractionated fluorescent probes indicated that the basal region was only penetrated by the lowest molecular weight probes with a hydrated radius of 2.2 nm or less. These observations indicate the selection of a unique, thick (>4,000 μm) microbial community in which a self-organized architecture promotes the maintenance of optimal conditions and metabolism throughout the biofilm community.}, } @article {pmid30332894, year = {2018}, author = {Wojciech, J and Kamila, M and Wojciech, B}, title = {Investigation of the population dynamics within a Pseudomonas aeruginosa biofilm using a flow based biofilm model system and flow cytometric evaluation of cellular physiology.}, journal = {Biofouling}, volume = {34}, number = {8}, pages = {835-850}, doi = {10.1080/08927014.2018.1508569}, pmid = {30332894}, issn = {1029-2454}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Flow Cytometry ; *Models, Biological ; Population Dynamics ; Pseudomonas aeruginosa/*growth & development/physiology ; *Stainless Steel ; }, abstract = {In this study a flow based biofilm model system was used to simulate the formation of Pseudomonas aeruginosa biofilms on a stainless steel surface. To investigate the complexity of biofilm-associated P. aeruginosa populations a combination of microscopic observations and flow cytometric analysis (FCM) was adopted. Biofilm-associated P. aeruginosa cells were evaluated (1) under optimal vs reduced nutrient-availability at the initial adhesion stage, and (2) irrespective of nutrient-availability within a mature biofilm. Microscopic estimation of the extent of attachment revealed more effective colonization upon optimal vs starvation conditions. FCM allowed an in situ evaluation of P. aeruginosa vitality, using cellular redox potential measurements to discriminate active, mid-active and non-active sub-populations. Samples from recently attached cells and mature biofilms showed significant differences in the percentages of bacterial cells from the defined sub-populations. The approach demonstrated that distribution of individual P. aeruginosa sub-populations was influenced by the stage of the biofilm life-cycle and nutrient availability.}, } @article {pmid30329046, year = {2019}, author = {Recacha, E and Machuca, J and Díaz-Díaz, S and García-Duque, A and Ramos-Guelfo, M and Docobo-Pérez, F and Blázquez, J and Pascual, A and Rodríguez-Martínez, JM}, title = {Suppression of the SOS response modifies spatiotemporal evolution, post-antibiotic effect, bacterial fitness and biofilm formation in quinolone-resistant Escherichia coli.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {74}, number = {1}, pages = {66-73}, doi = {10.1093/jac/dky407}, pmid = {30329046}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; DNA-Binding Proteins/deficiency ; *Drug Resistance, Bacterial ; Escherichia coli/*drug effects/enzymology/*growth & development ; Escherichia coli Proteins ; Gene Deletion ; Microbial Sensitivity Tests ; Rec A Recombinases ; *SOS Response, Genetics ; Spatio-Temporal Analysis ; }, abstract = {BACKGROUND: Suppression of the SOS response has been proposed as a therapeutic strategy for potentiating quinolones against susceptible, low-level quinolone-resistant (LLQR) and resistant Enterobacteriaceae.

OBJECTIVES: To monitor the functionality of the SOS response in the evolution towards clinical quinolone resistance and study its impact on the evolution of spatiotemporal resistance.

METHODS: An isogenic collection of Escherichia coli (derived from the strain ATCC 25922) carrying combinations of chromosomally and plasmid-mediated quinolone resistance mechanisms (including susceptible, LLQR and resistant phenotypes) and exhibiting a spectrum of SOS activity was used. Relevant clinical parameters such as mutation rate, mutant prevention concentration (MPC), bacterial fitness, biofilm formation and post-antibiotic effect (PAE) were evaluated.

RESULTS: Inactivating the SOS response (recA deletion) led to a decrease in mutation rate (∼103 fold) in LLQR compared with WT strains at ciprofloxacin concentrations of 1 mg/L (the EUCAST breakpoint for resistance) and 2.5 mg/L (Cmax), as well as a remarkable delay in the spatiotemporal evolution of quinolone resistance. For all strains, there was an 8-fold decrease in MPC in RecA-deficient strains, with values for LLQR strains decreasing below the Cmax of ciprofloxacin. Inactivation of the SOS response reduced competitive fitness by 33%-50%, biofilm production by 22%-80% and increased the PAE by ∼3-4 h at sub-MIC concentrations of ciprofloxacin.

CONCLUSIONS: Our data indicate that suppression of the SOS response affects key bacterial traits and is a promising strategy for reversing and tackling the evolution of antibiotic resistance in E. coli, including low-level and resistant phenotypes at therapeutic quinolone concentrations.}, } @article {pmid30328144, year = {2018}, author = {Li, Z and Behrens, AM and Ginat, N and Tzeng, SY and Lu, X and Sivan, S and Langer, R and Jaklenec, A}, title = {Biofilm-Inspired Encapsulation of Probiotics for the Treatment of Complex Infections.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {30}, number = {51}, pages = {e1803925}, doi = {10.1002/adma.201803925}, pmid = {30328144}, issn = {1521-4095}, support = {//Janggen-Pöhn-Foundation/ ; //Beatrice Beck-Schimmer/ ; //Hans-Ruedi Gonzenbach/ ; }, mesh = {Alginic Acid/chemistry ; *Biofilms ; Biomimetic Materials/*chemistry ; Capsules ; Drug Carriers/*chemistry ; Infections/*drug therapy ; Probiotics/*chemistry/*therapeutic use ; }, abstract = {The emergence of antimicrobial resistance poses a major challenge to healthcare. Probiotics offer a potential alternative treatment method but are often incompatible with antibiotics themselves, diminishing their overall therapeutic utility. This work uses biofilm-inspired encapsulation of probiotics to confer temporary antibiotic protection and to enable the coadministration of probiotics and antibiotics. Probiotics are encapsulated within alginate, a crucial component of pseudomonas biofilms, based on a simple two-step alginate cross-linking procedure. Following exposure to the antibiotic tobramycin, the growth and metabolic activity of encapsulated probiotics are unaffected by tobramycin, and they show a four-log survival advantage over free probiotics. This results from tobramycin sequestration on the periphery of alginate beads which prevents its diffusion into the core but yet allows probiotic byproducts to diffuse outward. It is demonstrated that this approach using tobramycin combined with encapsulated probiotic has the ability to completely eradicate methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in coculture, the two most widely implicated bacteria in chronic wounds.}, } @article {pmid30326805, year = {2018}, author = {Joe, H and Seo, YJ}, title = {A newly designed tympanostomy stent with TiO2 coating to reduce Pseudomonas aeruginosa biofilm formation.}, journal = {Journal of biomaterials applications}, volume = {33}, number = {4}, pages = {599-605}, doi = {10.1177/0885328218802103}, pmid = {30326805}, issn = {1530-8022}, mesh = {Alloys/*chemistry ; Bacterial Adhesion ; *Biofilms ; Carbenicillin/pharmacology ; Coated Materials, Biocompatible/*chemistry ; Drug Resistance, Bacterial ; Equipment Design ; Humans ; Middle Ear Ventilation/*instrumentation ; Pseudomonas aeruginosa/*physiology ; Silicones/chemistry ; Stents/*microbiology ; Titanium/*chemistry ; }, abstract = {Biofilm formation has been implicated as a cause of post-tympanostomy tube otorrhea in patients suffering from otitis media with effusion, and biofilms have been found to adhere to all available types of tympanostomy tubes (TT) made from silicone. In this study, we present a novel stent designed with a reduced surface area and a titanium dioxide (TiO2) coating to prevent biofilm formation. Using a radio frequency power supply, tympanostomy stents (TS) made from Nitinol (Nikel-titanium) were coated with TiO2 to form an oxide layer on the metallic target. We successfully reproduced biofilms with carbenicillin-resistant Pseudomonas aeruginosa strain, PAO1-GFP (green fluorescent protein) on the tubes in vitro. We then compared the levels of biofilm formation by this strain on the two types of implants using several methods, including bacterial quantification, electron microscopy, and confocal laser fluorescent microscopy. Our results provide definitive evidence that the combination of the TiO2 coating and minimized surface area of the Nitinol stent inhibited the P. aeruginosa biofilm formation. The ability of the TS to prevent viable bacteria colonization (over 10 folds, compared to silicone TT) was verified by anti-biofilm test. Future studies will reveal more useful in reducing otorrhea and plugging complications as a novel tympanostomy tube.}, } @article {pmid30325949, year = {2018}, author = {Wongsaroj, L and Saninjuk, K and Romsang, A and Duang-Nkern, J and Trinachartvanit, W and Vattanaviboon, P and Mongkolsuk, S}, title = {Pseudomonas aeruginosa glutathione biosynthesis genes play multiple roles in stress protection, bacterial virulence and biofilm formation.}, journal = {PloS one}, volume = {13}, number = {10}, pages = {e0205815}, pmid = {30325949}, issn = {1932-6203}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cell Movement ; Drosophila melanogaster/microbiology ; Ethylmaleimide/pharmacology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Glutathione/*biosynthesis ; Mutation ; Oligopeptides/genetics/metabolism ; Oxidants/chemistry ; Paraquat/pharmacology ; Pseudomonas Infections ; Pseudomonas aeruginosa/genetics/*metabolism ; Pyocyanine/genetics/metabolism ; *Virulence ; Virulence Factors/genetics/metabolism ; }, abstract = {Pseudomonas aeruginosa PAO1 contains gshA and gshB genes, which encode enzymes involved in glutathione (GSH) biosynthesis. Challenging P. aeruginosa with hydrogen peroxide, cumene hydroperoxide, and t-butyl hydroperoxide increased the expression of gshA and gshB. The physiological roles of these genes in P. aeruginosa oxidative stress, bacterial virulence, and biofilm formation were examined using P. aeruginosa ΔgshA, ΔgshB, and double ΔgshAΔgshB mutant strains. These mutants exhibited significantly increased susceptibility to methyl viologen, thiol-depleting agent, and methylglyoxal compared to PAO1. Expression of functional gshA, gshB or exogenous supplementation with GSH complemented these phenotypes, which indicates that the observed mutant phenotypes arose from their inability to produce GSH. Virulence assays using a Drosophila melanogaster model revealed that the ΔgshA, ΔgshB and double ΔgshAΔgshB mutants exhibited attenuated virulence phenotypes. An analysis of virulence factors, including pyocyanin, pyoverdine, and cell motility (swimming and twitching), showed that these levels were reduced in these gsh mutants compared to PAO1. In contrast, biofilm formation increased in mutants. These data indicate that the GSH product and the genes responsible for GSH synthesis play multiple crucial roles in oxidative stress protection, bacterial virulence and biofilm formation in P. aeruginosa.}, } @article {pmid30325394, year = {2018}, author = {Liu, S and Cao, S and Guo, J and Luo, L and Zhou, Y and Lin, C and Shi, J and Fan, C and Lv, M and Wang, L}, title = {Graphene oxide-silver nanocomposites modulate biofilm formation and extracellular polymeric substance (EPS) production.}, journal = {Nanoscale}, volume = {10}, number = {41}, pages = {19603-19611}, doi = {10.1039/c8nr04064h}, pmid = {30325394}, issn = {2040-3372}, abstract = {Biofilms with positive and negative actions ubiquitously affect medical infections, environmental remediation and industrial processes. However, it remains challenging to control the growth of harmful biofilms as well as to exploit the use of beneficial biofilms. Here we investigated the effect of an antibacterial graphene oxide-silver nanoparticles (GO-AgNPs) composite on Pseudomonas aeruginosa biofilm formation. We found that GO-AgNPs prevented biofilm formation in a dose-dependent manner, with a threshold of 15 μg mL[-1]. Interestingly, the bacterial biomass significantly decreased, but extracellular polymeric substance (EPS) production remarkably increased in mature biofilms treated with GO-AgNPs of an appropriate concentration, suggesting that GO-AgNPs effectively modulate biofilm development and structure. Moreover, we established that GO-AgNPs caused bacterial death via both physical damage and oxidative stress, showing the synergic action of GO and AgNPs. These findings facilitate the use of graphene-based nanocomposites for greener antibiotic applications.}, } @article {pmid30325222, year = {2018}, author = {Trmcic, A and Chen, H and Trząskowska, M and Tamber, S and Wang, S}, title = {Biofilm-Forming Capacity of Five Salmonella Strains and Their Fate on Postharvest Mini Cucumbers.}, journal = {Journal of food protection}, volume = {81}, number = {11}, pages = {1871-1879}, doi = {10.4315/0362-028X.JFP-18-180}, pmid = {30325222}, issn = {1944-9097}, mesh = {Biofilms/*growth & development ; *Cucumis sativus/microbiology ; Food Contamination/*analysis ; *Salmonella enterica/physiology ; *Salmonella enteritidis/physiology ; }, abstract = {Salmonella enterica is one of the pathogens that is frequently identified as the cause of fresh produce-related outbreaks. Biofilm formation is a factor that can contribute to pathogen survival on produce surface. The goal of our current research was to investigate the survival of five S. enterica strains representing different serotypes (i.e., Typhimurium, Enteritidis, Daytona, Poona, and Newport) on whole mini cucumbers stored at refrigeration (4°C) and room temperature (22°C). We also determined the strains survival on glass slides and in phosphate-buffered saline at 4 and 22°C, as well as the ability to form biofilms on a solid-liquid interphase. A rapid decrease in cell density (>4-log reduction over 8 days) of all five tested strains was observed on glass slides, while a slower die-off (<1-log reduction in 8 days) was observed in PBS. No significant difference in the die-off rate was observed among the five strains at 4 or 22°C. The die-off rate on the surface of mini cucumbers at 4°C was significantly slower (P < 0.02) for Salmonella Enteritidis LMFS-S-JF-005 compared with the remaining four strains. At 22°C, Salmonella Poona S306 was able to grow by more than 1.5 log units on whole mini cucumbers over a period of 8 days, while the cell density of the other four strains remained at the same level compared with day 0. At this temperature, Salmonella Poona S306 was also able to form significantly stronger biofilms on a solid-liquid interphase (P < 0.01) and was the only strain that presented a red, dry, and rough morphotype on Congo red agar plates, indicating the formation of both curli fimbriae and cellulose. These results revealed that the fate of Salmonella on mini cucumbers is strain specific, which highlighted the need for tailored mitigation strategies, such as the effective control of temperature and moisture for limiting the survival or growth of high-risk Salmonella strains between harvest and consumption of fresh produce.}, } @article {pmid30324376, year = {2018}, author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L}, title = {Mechanistic understanding of cerium oxide nanoparticle-mediated biofilm formation in Pseudomonas aeruginosa.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {34}, pages = {34765-34776}, pmid = {30324376}, issn = {1614-7499}, support = {No.51722902//National Natural Science Funds for Excellent Young Scholar/ ; No.51421006//the National Science Funds for Creative Research Groups of China/ ; 2018B671X14//the Fundamental Research Funds for the Central Universities/ ; No. 91647206//the Key Program of National Natural Science Foundation of China/ ; BK20160038//the Outstanding Youth Fund of Natural Science Foundation of Jiangsu, China/ ; }, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Bacterial Adhesion/drug effects ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Cerium/*pharmacology ; DNA, Bacterial/metabolism ; Furans/pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Glycolipids/metabolism ; *Nanoparticles/chemistry ; Pseudomonas aeruginosa/*drug effects/pathogenicity/*physiology ; Pyocyanine/metabolism ; Quinolones/metabolism ; Quorum Sensing/drug effects/genetics ; Reactive Oxygen Species/metabolism ; Virulence Factors/genetics ; }, abstract = {In this study, the biofilm formation of Pseudomonas aeruginosa in the presence of cerium oxide nanoparticles (CeO2 NPs) was investigated. With the addition of 0.1 mg/L and 1 mg/L CeO2 NPs, the biofilm development was substantially enhanced. During the attachment process, the enhanced surface hydrophobicity and excess production of mannosan and rhamnolipids in CeO2 NP treatments were detected, which were conductive to the colonization of bacterial cells. During the maturation period, the biofilm biomass was accelerated by the improved aggregation percentage as well as the secretion of extracellular DNA and pyocyanin. The reactive oxygen species (ROS) generated by CeO2 NPs were found to activate the N-butyryl homoserine lactone (C4-HSL) and quinolone signals secreted by Pseudomonas aeruginosa. Moreover, the quorum sensing (QS) systems of rhl and pqs were initiated, reflected by the stimulated expression levels of biofilm formation-related genes rhlI-rhlR, rhlAB, and pqsR-pqsA. The addition of a quorum quencher, furanone C-30, significantly declined the activities of QS-controlled catalase and superoxide dismutase. A dose of antioxidant, ascorbic acid, effectively relieved the accelerating effects of NPs on biofilm formation. These results indicated that CeO2 NPs could accelerate biofilm formation through the interference of QS system by generating ROS, which provides possible targets for controlling biofilm growth in the NP exposure environments.}, } @article {pmid30322852, year = {2019}, author = {Palmer, SR and Ren, Z and Hwang, G and Liu, Y and Combs, A and Söderström, B and Lara Vasquez, P and Khosravi, Y and Brady, LJ and Koo, H and Stoodley, P}, title = {Streptococcus mutans yidC1 and yidC2 Impact Cell Envelope Biogenesis, the Biofilm Matrix, and Biofilm Biophysical Properties.}, journal = {Journal of bacteriology}, volume = {201}, number = {1}, pages = {}, pmid = {30322852}, issn = {1098-5530}, support = {K99 DE023833/DE/NIDCR NIH HHS/United States ; P30 CA016058/CA/NCI NIH HHS/United States ; R00 DE023833/DE/NIDCR NIH HHS/United States ; R01 DE008007/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; *Biophysical Phenomena ; Cell Wall/*metabolism ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; Gene Deletion ; Glucans/chemistry/*metabolism ; Streptococcus mutans/*enzymology/genetics/growth & development ; }, abstract = {Proper envelope biogenesis of Streptococcus mutans, a biofilm-forming and dental caries-causing oral pathogen, requires two paralogs (yidC1 and yidC2) of the universally conserved YidC/Oxa1/Alb3 family of membrane integral chaperones and insertases. The deletion of either paralog attenuates virulence in vivo, but the mechanisms of disruption remain unclear. Here, we determined whether the deletion of yidC affects cell surface properties, extracellular glucan production, and/or the structural organization of the exopolysaccharide (EPS) matrix and biophysical properties of S. mutans biofilm. Compared to the wild type, the ΔyidC2 mutant lacked staining with fluorescent vancomycin at the division septum, while the ΔyidC1 mutant resembled the wild type. Additionally, the deletion of either yidC1 or yidC2 resulted in less insoluble glucan synthesis but produced more soluble glucans, especially at early and mid-exponential-growth phases. Alteration of glucan synthesis by both mutants yielded biofilms with less dry weight and insoluble EPS. In particular, the deletion of yidC2 resulted in a significant reduction in biofilm biomass and pronounced defects in the spatial organization of the EPS matrix, thus modifying the three-dimensional (3D) biofilm architecture. The defective biofilm harbored smaller bacterial clusters with high cell density and less surrounding EPS than those of the wild type, which was stiffer in compression yet more susceptible to removal by shear. Together, our results indicate that the elimination of either yidC paralog results in changes to the cell envelope and glucan production that ultimately disrupts biofilm development and EPS matrix structure/composition, thereby altering the physical properties of the biofilms and facilitating their removal. YidC proteins, therefore, represent potential therapeutic targets for cariogenic biofilm control.IMPORTANCE YidC proteins are membrane-localized chaperone insertases that are universally conserved in all bacteria and are traditionally studied in the context of membrane protein insertion and assembly. Both YidC paralogs of the cariogenic pathogen Streptococcus mutans are required for proper envelope biogenesis and full virulence, indicating that these proteins may also contribute to optimal biofilm formation in streptococci. Here, we show that the deletion of either yidC results in changes to the structure and physical properties of the EPS matrix produced by S. mutans, ultimately impairing optimal biofilm development, diminishing its mechanical stability, and facilitating its removal. Importantly, the universal conservation of bacterial yidC orthologs, combined with our findings, provide a rationale for YidC as a possible drug target for antibiofilm therapies.}, } @article {pmid30322270, year = {2018}, author = {Wijesinghe, MS and Wen, J and Oh, JM and Chow, KF and Sun, Y}, title = {Demonstration of biofilm removal from type 304 stainless steel using pulsed-waveform electropolishing.}, journal = {Biofouling}, volume = {34}, number = {7}, pages = {731-739}, doi = {10.1080/08927014.2018.1492715}, pmid = {30322270}, issn = {1029-2454}, mesh = {*Biofilms ; Electrochemical Techniques/*methods ; Electrodes ; Stainless Steel ; Staphylococcus epidermidis ; }, abstract = {This article describes an electrochemical method to remove bacterial biofilm from a stainless steel (SS) surface using a potential pulse/reverse pulse technique. This technique employs a periodic waveform that consists of anodic and cathodic pulses. The pulses can effectively strip a thin layer of metal off the SS surface, along with the adherent biofilm, in a saline solution. Not only can the pulses effectively remove biofilm from the SS surface, but they also regenerate the original mirror-like shiny surface. The importance of this electrochemical biofilm removal method is its wide applicability for any types of biofilms. That is, instead of directly removing the biofilm, it removes a very thin layer of the metal under the biofilm. Thus, the removal process is independent to the nature of the biofilms. Furthermore, this electrochemical biofilm removal method is rapid (less than 30 s of potential pulse time) and does not require hazardous chemicals.}, } @article {pmid30320445, year = {2019}, author = {Zhang, Y and Li, C and Wu, Y and Zhang, Y and Zhou, Z and Cao, B}, title = {A microfluidic gradient mixer-flow chamber as a new tool to study biofilm development under defined solute gradients.}, journal = {Biotechnology and bioengineering}, volume = {116}, number = {1}, pages = {54-64}, doi = {10.1002/bit.26852}, pmid = {30320445}, issn = {1097-0290}, mesh = {Biofilms/*growth & development ; Calcium/metabolism ; Comamonas testosteroni/*drug effects/growth & development ; Culture Media/*chemistry ; *Lab-On-A-Chip Devices ; Microfluidics/*instrumentation/*methods ; Nitrates/metabolism ; Shewanella/*drug effects/growth & development ; }, abstract = {Understanding the dynamics of biofilm development in response to chemical cues and signals is required toward the development of controllable biofilm-mediated bioprocesses. In this study, we report a new biofilm growth system that integrates a microfluidic gradient mixer with a biofilm growth chamber. The biofilm growth system allows biofilms to grow under defined solute gradients and enables nondestructive monitoring of the biofilm development dynamics in response to the defined gradients. The solute gradients generated in the system were simulated and then validated experimentally. We then demonstrated the applicability of the biofilm growth system in studying biofilm development under defined solute gradients. Specifically, we examined biofilm development of Shewanella oneidensis and Comamonas testosteroni under a defined calcium and nitrate gradient, respectively. Using two C. testosteroni strains (WDL7 and I2), we further demonstrated the applicability of our biofilm growth system to study the development of coculture biofilms under a defined solute gradient. Our results show that the biofilm growth system we have developed here can be a promising tool to reveal the dynamics of biofilm development in response to chemical cues and signals as well as the interorganism interactions in coculture biofilms.}, } @article {pmid30320255, year = {2018}, author = {Bagchi, D and Rathnam, VSS and Lemmens, P and Banerjee, I and Pal, SK}, title = {NIR-Light-Active ZnO-Based Nanohybrids for Bacterial Biofilm Treatment.}, journal = {ACS omega}, volume = {3}, number = {9}, pages = {10877-10885}, pmid = {30320255}, issn = {2470-1343}, abstract = {Nanomaterials with antimicrobial properties triggered by external stimuli appear to be a promising and innovative substitute for the destruction of antibiotic-resistant superbugs as they can induce multiple disruptions in the cellular mechanism. This study demonstrates the use of squaraine (SQ) dye as the photosensitive material, activated in the near-infrared tissue-transparent therapeutic window. The dye has been covalently attached to the ZnO nanoparticle surface, forming ZnO-SQ nanohybrids. The formation of the nanohybrids is confirmed using Fourier transform infrared and other optical spectroscopic methods. The photoinduced interfacial electron transfer process (as confirmed using the time-resolved fluorescence technique) from the excited state of SQ to the conduction band of ZnO is responsible for the greater reactive oxygen species (ROS) generation ability of the nanohybrid. The production of photoactivated ROS (especially singlet oxygen species) by ZnO-SQ provides remarkable antimicrobial action against clinically significant Staphylococcus aureus. Detailed investigations suggest synergistic involvement of cell membrane disruption and nanoparticle internalization followed by photoinduced intracellular ROS generation, which result in an unprecedented 95% bacterial killing activity by the nanohybrid. Moreover, the efficacy of the nanohybrid for disruption of bacterial biofilms has been examined. The electron microscopic images suggest significant bacterial cell death following structural alteration and reduced adherence property of the biofilms. Nanodimension-driven greater internalization of ZnO-SQ followed by an improved dissolution of ZnO in an acidic environment of the biofilm as well as red-light-driven interfacial charge separation and ROS generation improves the efficacy of the material for biofilm destruction. An artificial medical implant mimicking titanium sheets coated with ZnO-SQ depicts light-triggered disruption in the adherence property of matured biofilms. The cytotoxicity and hemolysis assays show inherent biocompatibility of the photoactive nanohybrid. This study is notably promising for the treatment of life-threatening drug-resistant infections and eradication of biofilms formed within artificial implants.}, } @article {pmid30317126, year = {2019}, author = {Harper, RA and Carpenter, GH and Proctor, GB and Harvey, RD and Gambogi, RJ and Geonnotti, AR and Hider, R and Jones, SA}, title = {Diminishing biofilm resistance to antimicrobial nanomaterials through electrolyte screening of electrostatic interactions.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {173}, number = {}, pages = {392-399}, doi = {10.1016/j.colsurfb.2018.09.018}, pmid = {30317126}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Buffers ; Drug Resistance, Bacterial/drug effects ; Electrolytes/*chemistry ; Extracellular Polymeric Substance Matrix/chemistry ; Liposomes/chemistry ; Nanostructures/*chemistry ; Particle Size ; Permeability ; Static Electricity ; Streptococcus oralis/chemistry/*drug effects/growth & development ; alpha-Tocopherol/*analogs & derivatives/chemistry/pharmacology ; }, abstract = {The extracellular polymer substances (EPS) generated by biofilms confers resistance to antimicrobial agents through electrostatic and steric interactions that hinder molecular diffusion. This resistance mechanism is particularly evident for antibacterial nanomaterials, which inherently diffuse more slowly compared to small organic antibacterial agents. The aim of this study was to determine if a biofilm's resistance to antibacterial nanomaterial diffusion could be diminished using electrolytes to screen the EPS's electrostatic interactions. Anionic (+) alpha-tocopherol phosphate (α-TP) liposomes were used as the antimicrobial nanomaterials in the study. They self-assembled into 700 nm sized structures with a zeta potential of -20 mV that were capable of killing oral bacteria (S. oralis growth inhibition time of 3.34 ± 0.52 h). In a phosphate (-ve) buffer the -ve α-TP liposomes did not penetrate multispecies oral biofilms, but in a Tris (hydroxymethyl)aminomethane (+ve) buffer they did (depth - 12.4 ± 3.6 μm). The Tris did not modify the surface charge of the α-TP nanomaterials, rather it facilitated the α-TP-biofilm interactions through electrolyte screening (Langmuir modelled surface pressure increase of 2.7 ± 1.8 mN/ m). This data indicated that EPS resistance was mediated through charge repulsion and that this effect could be diminished through the co-administration of cationic electrolytes.}, } @article {pmid30317111, year = {2019}, author = {Corzo-Ariyama, HA and García-Heredia, A and Heredia, N and García, S and León, J and Jaykus, L and Solís-Soto, L}, title = {Phylogroups, pathotypes, biofilm formation and antimicrobial resistance of Escherichia coli isolates in farms and packing facilities of tomato, jalapeño pepper and cantaloupe from Northern Mexico.}, journal = {International journal of food microbiology}, volume = {290}, number = {}, pages = {96-104}, doi = {10.1016/j.ijfoodmicro.2018.10.006}, pmid = {30317111}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Capsicum/microbiology ; Cucumis melo/microbiology ; Drug Resistance, Bacterial/drug effects ; *Environmental Microbiology ; Escherichia coli/*classification/*drug effects/genetics/pathogenicity ; Farmers ; *Farms ; Humans ; Solanum lycopersicum/microbiology ; *Manufacturing and Industrial Facilities ; Mexico ; Phylogeny ; }, abstract = {The most commonly used indicator of fecal contamination in fresh produce production and packing is Escherichia coli. In depth analysis of the prevalence and characteristics of naturally occurring E. coli strains in these environments is important because it can (1) serve as an indicator of sources of fecal contamination; and (2) provide information on strain pathogenicity, persistence, and other defining characteristics such as multidrug resistance. In this study, we analyzed 341 E. coli strains isolated from the jalapeño pepper, tomato and cantaloupe farm environments, in Northeast Mexico. Strains were isolated from produce, farmworkers' hands, soil and water. Pathotypes, genotypes, biofilm formation and antibiotic resistance were characterized. Phylogenetic subgroups and identification of diarrheagenic E. coli were determined by PCR; biofilm formation was quantified using a plate-based colorimetric method. Antibiotic resistance was analyzed by the Kirby Bauer diffusion disc method. Most isolates (N = 293, 86%) belonged to phylogenetic group A. Only four isolates (1.2%) were diarrheagenic: EPEC (N = 3) and ETEC (N = 1). Antibiotic resistance to tetracycline (23.2%) and ampicillin (19.9%) was high, and only 3.5% of the strains presented resistance to >5 antibiotics. Biofilms were produced by most strains (76%), among which 34.4% were categorized as high producers. The presence of antibiotic resistant E. coli strains that may contain gene markers for pathogenicity and which can form biofilms suggests potential health risks for consumers.}, } @article {pmid30316009, year = {2018}, author = {Mahdhi, A and Leban, N and Chakroun, I and Bayar, S and Mahdouani, K and Majdoub, H and Kouidhi, B}, title = {Use of extracellular polysaccharides, secreted by Lactobacillus plantarum and Bacillus spp., as reducing indole production agents to control biofilm formation and efflux pumps inhibitor in Escherichia coli.}, journal = {Microbial pathogenesis}, volume = {125}, number = {}, pages = {448-453}, doi = {10.1016/j.micpath.2018.10.010}, pmid = {30316009}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacillus/isolation & purification/metabolism ; Biofilms/*drug effects ; Biological Transport, Active/*drug effects ; Environmental Microbiology ; Escherichia coli/chemistry/*drug effects/physiology ; Food Microbiology ; Hydrophobic and Hydrophilic Interactions/drug effects ; Indoles/*antagonists & inhibitors ; Lactobacillus plantarum/isolation & purification/metabolism ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/isolation & purification/*pharmacology ; Quorum Sensing/drug effects ; }, abstract = {The overuse of antibiotics and biofilm formation ability has led to the emergence of bacterial resistant strains. The combined use of several antibiotics has been found as an efficient strategy to overcome this resistance. In this study, two exopolysaccharides (EPS) obtained from Lactobacillus plantarum (EPS-Lp) and Bacillus spp. (EPS-B), isolated from a traditional Tunisian food "ricotta cheese" and hypersaline environment respectively, were used to counteract the biofilm formation and efflux pumps activities in Escherichia coli ATCC35218. The obtained results revealed that the tested EPSs can be effective against E. coli at a concentration > 1 mg/ml and were able to modulate biofilm formation by 50%. Moreover, at a concentration of 512 μg/ml, the tested EPSs inhibit the EtBr efflux in the tested bacteria and no significant difference was shown compared to cells treated with reserpine (P > 0.05). The positive effect of the tested EPSs may be due to the decrease of Indole production level proposed as a signal involved in quorum sensing and through the significant reduction of the hydrophobicity percentage between the treated and untreated cells. Overall, EPS-Lp and EPS-B, when used at appropriate concentration, may inhibit biofilm formation and reduce efflux pumps implicated in bacterial adhesion and antimicrobial resistance. These results make them an interesting candidate in the design of a new strategies to control bacterial biofilm-associated infections.}, } @article {pmid30315918, year = {2019}, author = {Koppen, BC and Mulder, PPG and de Boer, L and Riool, M and Drijfhout, JW and Zaat, SAJ}, title = {Synergistic microbicidal effect of cationic antimicrobial peptides and teicoplanin against planktonic and biofilm-encased Staphylococcus aureus.}, journal = {International journal of antimicrobial agents}, volume = {53}, number = {2}, pages = {143-151}, doi = {10.1016/j.ijantimicag.2018.10.002}, pmid = {30315918}, issn = {1872-7913}, mesh = {Aminoacyltransferases/genetics ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Carrier Proteins/genetics ; Drug Combinations ; Drug Synergism ; Membrane Transport Proteins/genetics ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/growth & development ; Staphylococcus epidermidis/drug effects/growth & development ; Teicoplanin/*pharmacology ; Cathelicidins ; }, abstract = {Antibiotic resistance and biofilm formation are the main reasons for failure in treatment of bacterial infections. This study aimed to identify synergistic combinations of conventional antibiotics and novel synthetic antimicrobial and antibiofilm peptides (SAAPs) inspired by the structures of the natural human cationic peptides LL-37 and thrombocidin-1 (TC-1). The LL-37-inspired lead peptide SAAP-148 was combined with antibiotics of different classes against Staphylococcus aureus, and showed synergy with teicoplanin. Synergy with teicoplanin was also observed with LL-37, the LL-37-inspired SAAP-276 and the TC-1-inspired TC84. Interestingly, no synergy was observed against Staphylococcus epidermidis. Furthermore, teicoplanin combined with SAAP-148 or SAAP-276 showed strong interaction against S. aureus biofilms. The dltABCD operon and the mprF gene in S. aureus conferred resistance to LL-37, but SAAP-148 proved to be indifferently potent against wild-type, ΔdltA and ΔmprF S. aureus strains. When used alone, relatively high concentrations of both LL-37 and teicoplanin (30-120 µM and 4-32 mg/L, respectively) were required to kill S. aureus. Resistance to LL-37 in S. aureus was overcome by combined use of teicoplanin and LL-37. Thus, teicoplanin potentiates peptide LL-37, enhancing the efficacy of the innate defence, and combining the novel peptides with teicoplanin offers potential for enhanced efficacy of treatment of S. aureus infections, including biofilms.}, } @article {pmid30312918, year = {2019}, author = {Zhang, H and Tian, Y and Kang, M and Chen, C and Song, Y and Li, H}, title = {Effects of chlorination/chlorine dioxide disinfection on biofilm bacterial community and corrosion process in a reclaimed water distribution system.}, journal = {Chemosphere}, volume = {215}, number = {}, pages = {62-73}, doi = {10.1016/j.chemosphere.2018.09.181}, pmid = {30312918}, issn = {1879-1298}, mesh = {Bacteria/drug effects/*growth & development ; Biofilms/drug effects/*growth & development ; Chlorine Compounds/*pharmacology ; Corrosion ; Disinfection/*methods ; *Halogenation ; Oxides/*pharmacology ; Water Purification/*methods ; Water Supply/*standards ; }, abstract = {In this work, reclaimed water treated with sodium hypochlorite (NaClO) or chlorine dioxide (ClO2) at 1, 2, and 4 mg/L was operated successively for 30 days respectively, in annular reactors with new cast iron coupons, corresponding to stages I (days 0-30), II (days 31-60), and III (days 61-90). The Illumina HiSeq 2500 sequencing platform was used to analyze the bacterial community composition, scanning electron microscopy and X-ray diffraction analyses were conducted to characterize corrosion scales, and the weight loss method was served to determine the general corrosion rate. Results reveal the precise disinfection effect on biofilm bacteria to be dose dependent and species specific. In stage I, disinfection caused a reduction in the number of operational taxonomic units, but, had little effect on biofilm composition. In stage II, NaClO and ClO2 induced a reduction of Proteobacteria proportion, but increased the dominance of Firmicutes; the diminished Proteobacteria in NaClO test mainly included Gammaproteobacteria, while, that in ClO2 test mainly included the Gammaproteobacteria and Betaproteobacteria. In stage III, Firmicutes presented a certain resistance to NaClO and ClO2 as the accumulation of corrosion scales. Results also indicated that disinfection enhanced the corrosion process, and the promoting effect of ClO2 was more pronounced than that of NaClO. Moreover, this promoting effect was more obvious in stage I than that in the latter two stages. The strong oxidization effect associated with disinfection in stage I was the dominant factor promoting corrosion, whereas, the bacterial community also played a crucial role in stages II and III.}, } @article {pmid30310963, year = {2018}, author = {Sakr, MM and Aboshanab, KM and Elkhatib, WF and Yassien, MA and Hassouna, NA}, title = {Overexpressed recombinant quorum quenching lactonase reduces the virulence, motility and biofilm formation of multidrug-resistant Pseudomonas aeruginosa clinical isolates.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {24}, pages = {10613-10622}, doi = {10.1007/s00253-018-9418-2}, pmid = {30310963}, issn = {1432-0614}, mesh = {Bacillus/genetics ; Biofilms/growth & development ; Carboxylic Ester Hydrolases/*genetics/metabolism ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli/genetics ; Gene Expression Regulation, Bacterial ; Glycolipids/metabolism ; Humans ; Pseudomonas aeruginosa/drug effects/genetics/isolation & purification/*pathogenicity ; Pyocyanine/metabolism ; Quorum Sensing/*genetics ; Recombinant Proteins/*genetics/metabolism ; Virulence/genetics ; }, abstract = {The increasing occurrence of resistance among Pseudomonas aeruginosa clinical isolates necessitates finding alternatives to antibiotics for controlling the infection of such pathogenic bacteria. In this study, lactonase gene ahl-1 from Bacillus weihenstephanensis isolate-P65 was successfully cloned and expressed in Escherichia coli BL21 (DE3) under the control of T7 promoter for utilizing its quorum quenching activity against three multidrug-resistant (MDR) P. aeruginosa clinical isolates. The biological activity of the overexpressed lactonase enzyme (Ahl-1), tested using a synthetic signal and Chromobacterium violaceum CV026 as a biosensor, displayed good catalytic activity using hexanoyl homoserine lactone (HHL) as a substrate and Chromobacterium violaceum (CV026) as a biosensor (77.2 and 133 nm min[-1] for the crude and the purified Ahl-lactonase enzymes, respectively). Upon challenging its ability to inhibit the virulence of three MDR P. aeruginosa clinical isolates, recombinant Ahl-1 successfully prevented the accumulation of acylhomoserine lactone signals resulting in a significant reduction in the investigated virulence determinants; protease (from 40 up to 75.5%), pyocyanin (48-75.9%), and rhamnolipids (52.7-63.4%) (P value < 0.05). Ahl-1 also displayed significant inhibitory activities on the swarming motility and biofilm formation of the three tested MDR P. aeruginosa clinical isolates (P value < 0.05). Consequently, Ahl-1 lactonase enzyme in this study is considered a promising therapeutic agent to inhibit P. aeruginosa pathogenicity with no fear of emergence of resistance.}, } @article {pmid30308791, year = {2019}, author = {Jacotot, A and Marchand, C and Allenbach, M}, title = {Biofilm and temperature controls on greenhouse gas (CO2 and CH4) emissions from a Rhizophora mangrove soil (New Caledonia).}, journal = {The Science of the total environment}, volume = {650}, number = {Pt 1}, pages = {1019-1028}, doi = {10.1016/j.scitotenv.2018.09.093}, pmid = {30308791}, issn = {1879-1026}, mesh = {Air Pollutants/*analysis ; *Biofilms ; Carbon Dioxide/*analysis ; Climate Change ; Environmental Monitoring ; Methane/*analysis ; New Caledonia ; Rhizophoraceae/*physiology ; Seasons ; Soil ; *Temperature ; *Wetlands ; }, abstract = {Seasonal variations of CO2 and CH4 fluxes were investigated in a Rhizophora mangrove forest that develops under a semi-arid climate, in New Caledonia. Fluxes were measured using closed incubation chambers connected to a CRDS analyzer. They were performed during low tide at light, in the dark, and in the dark after having removed the top 1-2 mm of soil, which may contain biofilm. CO2 and CH4 fluxes ranged from 31.34 to 187.48 mmol m[-2] day[-][1] and from 39.36 to 428.09 μmol m[-2] day[-][1], respectively. Both CO2 and CH4 emissions showed a strong seasonal variability with higher fluxes measured during the warm season, due to an enhanced production of these two gases within the soil. Furthermore, CO2 fluxes were higher in the dark than at light, evidencing photosynthetic processes at the soil surface and thus the role of biofilm in the regulation of greenhouse gas emissions from mangrove soils. The mean δ[13]C-CO2 value of the CO2 fluxes measured was -19.76 ± 1.19‰, which was depleted compared to the one emitted by root respiration (-22.32 ± 1.06‰), leaf litter decomposition (-21.43 ± 1.89‰) and organic matter degradation (-22.33 ± 1.82‰). This result confirmed the use of the CO2 produced within the soil by the biofilm developing at its surface. After removing the top 1-2 mm of soil, both CO2 and CH4 fluxes increased. Enhancement of CH4 fluxes suggests that biofilm may act as a physical barrier to the transfer of GHG from the soil to the atmosphere. However, the δ[13]C-CO2 became more enriched, evidencing that the biofilm was not integrally removed, and that its partial removal resulted in physical disturbance that stimulated CO2 production. Therefore, this study provides useful information to understand the global implication of mangroves in climate change mitigation.}, } @article {pmid30308310, year = {2018}, author = {Trigo-Gutierrez, JK and Sanitá, PV and Tedesco, AC and Pavarina, AC and Mima, EGO}, title = {Effect of Chloroaluminium phthalocyanine in cationic nanoemulsion on photoinactivation of multispecies biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {212-219}, doi = {10.1016/j.pdpdt.2018.10.005}, pmid = {30308310}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Candida albicans/drug effects ; Candida glabrata/drug effects ; Dose-Response Relationship, Drug ; Emulsions/*chemistry ; Indoles/administration & dosage/*pharmacology ; Nanoparticles/*chemistry ; Organometallic Compounds/administration & dosage/*pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Streptococcus mutans/drug effects ; }, abstract = {BACKGROUND: Photosensitizers in nanocarriers have been investigated for antimicrobial Photodynamic Therapy (aPDT). However, most studies are focused against microorganisms in planktonic or monospecies biofilm. Thus, this in vitro study evaluated the effect of aPDT using Chloroaluminium phthalocyanine (ClAlPc) in cationic nanoemulsion (NE) against Candida albicans, Candida glabrata and Streptococcus mutans grown as multispecies biofilm.

METHODS: Standard suspensions of each microorganism were added into wells of a microtiter plate for biofilm growth for 48 h in a candle jar. The biofilms were incubated with ClAlPc in cationic NE at 31.8 μM for 30 min and illuminated with red light fluence of 39.3 J/cm[2] (P+L+ group). Additional samples were treated only with photosensitizer (P+L-) or red light (P-L+) or neither (P-L-, control group). aPDT efficacy was assessed by colony quantification, biofilm's metabolic activity, total biomass, and confocal microscopy. Data were analyzed by ANOVA/Welch and post-hoc Tukey/Games-Howell tests (α = 0.05).

RESULTS: aPDT (P+L+) reduced the colony count in 1.30 to 2.24 lg10 and the metabolic activity in 53.7% compared with the control group (P-L-). The total biomass showed no statistical difference among the groups. The confocal microscopy analyzes showed uptake of the PS in the biofilm, and dead cells were observed in the biofilm treated with aPDT.

CONCLUSION: aPDT mediated by ClAlPc in cationic NE promoted photoinactivation of the multispecies biofilm, which was confirmed by colony quantification, metabolic activity, and confocal microscopy. However, the total biomass of the biofilm was not affected by the treatment.}, } @article {pmid30308309, year = {2018}, author = {Batinić, M and Ročan, M and Budimir, A and Anić, I and Bago, I}, title = {Comparison of final disinfection protocols using antimicrobial photodynamic therapy and different irrigants after single-file reciprocating instrumentation against intracanal bacterial biofilm - An in vitro study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {153-157}, doi = {10.1016/j.pdpdt.2018.10.006}, pmid = {30308309}, issn = {1873-1597}, mesh = {Biguanides/pharmacology ; Biofilms/*drug effects ; Combined Modality Therapy ; Edetic Acid/pharmacology ; Enterococcus faecalis/*drug effects ; Humans ; Phenothiazines/pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/pharmacology ; Polymers/pharmacology ; Random Allocation ; Root Canal Irrigants/*pharmacology ; Root Canal Preparation/*methods ; Sodium Hypochlorite/pharmacology ; }, abstract = {BACKGROUND: The aim of the study was to compare the efficacy of antimicrobial photodynamic therapy (aPDT) with irrigation protocols that include sodium hypochlorite (NaOCl), ethylenediaminotetraacetic acid (EDTA) or QMiX (combined irrigant: EDTA, chlorhexidine, detergent) solution after single-file reciprocating root canal instrumentation.

METHODS: The study sample included 68 extracted mandibular human single canal teeth. The canals were inoculated with bacterial suspension made of wild strain of Enterococcus faecalis. After 17 days of incubation, the samples were assigned to experimental groups according to the final disinfection protocol and a control group. The root canals in all groups were, firstly, instrumented with Wave One Gold reciprocating system. Then the canals were disinfected as follows: Group 1. 2.5% NaOCl and EDTA followed by the application of the aPDT; Group 2. 2.5% NaOCl, EDTA and 2.5% NaOCl; Group 3. 2.5% NaOCl and QMIX solution; Group 4. 2.5% NaOCl and EDTA. In the control group, the canals were irrigated with saline solution. Microbiological samples were collected at baseline, after single-file instrumentation and after the final disinfection protocols. The samples were plated onto Mitis Salivarius agar plates for incubation. The colony forming units (CFUs) were counted, and the final number was determined based on the dilution factor.

RESULTS: Reciprocating single-file instrumentation reduced CFUs significantly in all groups (p<0.05). No significant difference between Group 1 and Group 2 was observed (p=0.178). Irrigation with the QMiX was more efficient than the aPDT (p=0.02).

CONCLUSIONS: The aPDT used after irrigation with NaOCl and EDTA demonstrated similar antimicrobial efficacy as conventional irrigation with NaOCl.}, } @article {pmid30308132, year = {2018}, author = {Ong, KS and Mawang, CI and Daniel-Jambun, D and Lim, YY and Lee, SM}, title = {Current anti-biofilm strategies and potential of antioxidants in biofilm control.}, journal = {Expert review of anti-infective therapy}, volume = {16}, number = {11}, pages = {855-864}, doi = {10.1080/14787210.2018.1535898}, pmid = {30308132}, issn = {1744-8336}, mesh = {Animals ; Antioxidants/chemistry/pharmacology/*therapeutic use ; Biofilms/*drug effects ; Gene Expression Regulation/drug effects ; Humans ; Oxidative Stress/*drug effects/genetics ; Solubility ; }, abstract = {Biofilm formation is a strategy for microorganisms to adapt and survive in hostile environments. Microorganisms that are able to produce biofilms are currently recognized as a threat to human health. Areas covered: Many strategies have been employed to eradicate biofilms, but several drawbacks from these methods had subsequently raised concerns on the need for alternative approaches to effectively prevent biofilm formation. One of the main mechanisms that drives a microorganism to transit from a planktonic to a biofilm-sessile state, is oxidative stress. Chemical agents that could target oxidative stress regulators, for instance antioxidants, could therefore be used to treat biofilm-associated infections. Expert commentary: The focus of this review is to summarize the function and limitation of the current anti-biofilm strategies and will propose the use of antioxidants as an alternative method to treat, prevent and eradicate biofilms. Studies have shown that water-soluble and lipid-soluble antioxidants can reduce and prevent biofilm formation, by influencing the expression of genes associated with oxidative stress. Further in vivo work should be conducted to ensure the efficacy of these antioxidants in a biological environment. Nevertheless, antioxidants are promising anti-biofilm agents, and thus is a potential solution for biofilm-associated infections in the future.}, } @article {pmid30306008, year = {2018}, author = {Kim, G and Dasagrandhi, C and Kang, EH and Eom, SH and Kim, YM}, title = {In vitro antibacterial and early stage biofilm inhibitory potential of an edible chitosan and its phenolic conjugates against Pseudomonas aeruginosa and Listeria monocytogenes.}, journal = {3 Biotech}, volume = {8}, number = {10}, pages = {439}, pmid = {30306008}, issn = {2190-572X}, abstract = {In the present study, the antibacterial potential of chitosan grafted with phenolics (CPCs) such as caffeic acid (CCA), ferulic (CFA), and sinapic acid (CSA) were evaluated against foodborne pathogens like Pseudomonas aeruginosa (PA) and Listeria monocytogenes (LM). The geometric means of minimum inhibitory concentration (MIC range 0.05-0.33 mg/ml), bactericidal concentration (MBC range 0.30-0.45 mg/ml), biofilm inhibitory concentration (BIC range 0.42-0.83 mg/ml), and biofilm eradication concentration (BEC range 1.71-3.70 mg/ml) of CPCs were found to be lower than the MIC (0.12-1.08 mg/ml), MBC (0.17-1.84 mg/ml), BIC (4.0-4.50 mg/ml), and BEC (17.4-23.0 mg/ml) of unmodified chitosan against PA and LM. CPCs attenuated the biofilms of PA and LM by increasing the membrane permeability of bacteria embedded within the biofilms. Further, sub MIC of CPCs (0.5 × MIC) significantly reduced the biofilm adhesion (p < 0.001) by representative strains of LM (CCA: 72.2 ± 3.5, CFA: 79.3 ± 0.9, and CSA: 74.9 ± 1.5%) and PA (CCA: 64 ± 1.1, CFA: 67.8 ± 0.8, and CSA: 65.7 ± 4.9%). These results suggested the antibacterial and anti-biofilm potential of CPCs that can be exploited to control foodborne pathogenic infections.}, } @article {pmid30305150, year = {2018}, author = {Manandhar, S and Singh, A and Varma, A and Pandey, S and Shrivastava, N}, title = {Evaluation of methods to detect in vitro biofilm formation by staphylococcal clinical isolates.}, journal = {BMC research notes}, volume = {11}, number = {1}, pages = {714}, pmid = {30305150}, issn = {1756-0500}, mesh = {Biofilms/*growth & development ; Cross-Sectional Studies ; *Genes, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Nepal/epidemiology ; Phenotype ; Staphylococcal Infections/epidemiology/microbiology ; Staphylococcus/*classification/genetics/isolation & purification ; Staphylococcus aureus/*classification/genetics/isolation & purification ; Tertiary Care Centers ; }, abstract = {OBJECTIVE: Staphylococcus genus comprising both Staphylococcus aureus and coagulase negative staphylococci (CoNS) are widely distributed in nature and can infect diversity of hosts. Indeed, staphylococci are the major pathogens causing biofilm associated infections caused by contaminated hospital indwelling devices. These infections are persistent in nature being highly refractory to various stresses including antibiotics. Implementation of efficient diagnostic techniques for the biofilm production would help minimize the disease burden. Thus, early detection of pathogenic strains producing biofilms warrant the utmost importance in diagnostic laboratories especially in resource limited settings.

RESULT: Among 375 isolates collected from different clinical specimens, 214 (57%) were identified as coagulase negative staphylococci and 161 (43%) S. aureus. Detection of In-vitro biofilm formation in these isolates were carried out by three commonly used phenotypic assays and a genotypic assay. While evaluating the results, tissue-culture method with supplemented glucose and sucrose showed the best correlation with the results of genotypic assay.}, } @article {pmid30304991, year = {2019}, author = {Li, H and Qin, Y and Mao, X and Zheng, W and Luo, G and Xu, X and Zheng, J}, title = {Silencing of cyt-c4 led to decrease of biofilm formation in Aeromonas hydrophila.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {83}, number = {2}, pages = {221-232}, doi = {10.1080/09168451.2018.1528543}, pmid = {30304991}, issn = {1347-6947}, mesh = {Aeromonas hydrophila/*genetics/*metabolism/pathogenicity ; Amino Acid Sequence ; Aquaculture ; Bacterial Adhesion/genetics ; Base Sequence ; *Biofilms ; Cytochrome c Group/*genetics ; DNA Transposable Elements ; Drug Resistance, Bacterial/genetics ; *Gene Silencing ; *Genes, Bacterial ; Mutagenesis, Insertional ; Open Reading Frames ; RNA Interference ; Virulence ; }, abstract = {Aquaculture suffers from a number of diseases caused by Aeromonas hydrophila. Biofilm can protect bacteria from antibiotic therapy. To identify the genes those play crucial roles in A. hydrophila biofilm formation, a library of mini-Tn10 transposon insertion mutants of A. hydrophila B11 has been constructed, and 10 mutants were subjected to biofilm formation assay. The biofilm formation ability of mutant (B188) was significantly decreased compared with B11. The DNA sequence flanking the mini-Tn10 transposon inserted showed that an ORF of approximately 576 bp of the mutant strain B188 was inserted. This ORF putatively displays the highest identity (92%) with the cytochrome c4 gene (cyt-c4) of A. hydrophila subsp. hydrophila ATCC 7966. Silencing cyt-c4 led to deficiencies in biofilm formation, adhesion, drug resistance and pathogenicity of A. hydrophila, which suggests that cyt-c4 plays crucial role in the biofilm formation and virulence mechanisms of A. hydrophila. ABBREVIATIONS: GEN: gentamycin; SDZ: sulfadiazine; AK: amikacin; P: penicillin; CFP: cefoperazone; LEV: levofloxacin; MH: minocycline; FFC: florfenicol; TE: tetracycline; AMP: ampicillin; KAN: kanamycin; STR: streptomycin; SXT: sulfamethoxazole/trimethoprim; DO: doxycycline; OT: Oxytetracycline.}, } @article {pmid30304890, year = {2018}, author = {Shi, C and Li, M and Muhammad, I and Ma, X and Chang, Y and Li, R and Li, C and He, J and Liu, F}, title = {Combination of berberine and ciprofloxacin reduces multi-resistant Salmonella strain biofilm formation by depressing mRNA expressions of luxS, rpoE, and ompR.}, journal = {Journal of veterinary science}, volume = {19}, number = {6}, pages = {808-816}, pmid = {30304890}, issn = {1976-555X}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Bacterial Proteins/genetics/*metabolism ; Berberine/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Carbon-Sulfur Lyases/genetics/*metabolism ; Ciprofloxacin/administration & dosage/*pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial ; Drug Therapy, Combination ; Microbial Sensitivity Tests ; RNA, Messenger/genetics ; Salmonella/*drug effects ; Sigma Factor/genetics/*metabolism ; Trans-Activators/genetics/*metabolism ; }, abstract = {Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at 1/2 × MIC/FIC concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at 1/4 × FIC concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p ＜ 0.01) at 1/2 × MIC/FIC concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the 1/4 × FIC concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.}, } @article {pmid30304271, year = {2018}, author = {Sahal, G and Bilkay, IS}, title = {Distribution of clinical isolates of Candida spp. and antifungal susceptibility of high biofilm-forming Candida isolates.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {51}, number = {5}, pages = {644-650}, doi = {10.1590/0037-8682-0136-2018}, pmid = {30304271}, issn = {1678-9849}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/classification/*drug effects/physiology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {INTRODUCTION: The increase in the incidence of fungal infections, especially those caused by Candida albicans and other Candida species, necessitates the understanding and treatment of Candida-associated infections. In this study, we aimed to investigate the identification, distribution, and biofilm formation ability of different clinical Candida isolates and evaluate the distribution and antifungal susceptibilities of high biofilm-forming (HBF) Candida isolates.

METHODS: For identification, carbohydrate fermentation, carbohydrate assimilation, and ChromAgar tests were used. Biofilm formation was assessed using crystal violet binding assay, while the susceptibility to antifungal agents was determined using ATBTM Fungus 3 test kits.

RESULTS: The majority of Candida species were C. parapsilosis (31.3%; 31/99) and C. tropicalis (30.3%; 30/99). C. tropicalis was found to be the most frequently isolated species among all HBF Candida species. HBF Candida isolates were more frequently isolated from vaginal swab (35.7%; 10/28), tracheal aspirate (17.9%; 5/28), and urine (17.9%; 5/28). The majority of tested isolates were resistant to itraconazole and voriconazole, whereas no isolate was deemed resistant to 5-flucytosine.

CONCLUSIONS: C. tropicalis displays the highest biofilm formation ability among all the Candida species evaluated, and HBF Candida isolates were more frequently seen in vaginal swab, tracheal aspirate, and urine samples. Our findings revealed that 5-flucytosine is the most efficient antifungal agent against HBF Candida isolates.}, } @article {pmid30304265, year = {2018}, author = {Sohail, M and Latif, Z}, title = {Molecular analysis, biofilm formation, and susceptibility of methicillin-resistant Staphylococcus aureus strains causing community- and health care-associated infections in central venous catheters.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {51}, number = {5}, pages = {603-609}, doi = {10.1590/0037-8682-0373-2017}, pmid = {30304265}, issn = {1678-9849}, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/genetics ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections/*microbiology ; Child ; Community-Acquired Infections/*microbiology ; Cross Infection/*microbiology ; Female ; Genes, Bacterial/genetics ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Middle Aged ; Staphylococcal Infections/*microbiology ; Young Adult ; }, abstract = {INTRODUCTION: The behavior of methicillin-resistant Staphylococcus aureus (MRSA) isolated from central venous catheter-related infection was evaluated to determine its biofilm potential, antimicrobial resistance, and adhesion genes.

METHODS: A total of 1,156 central venous catheters (CVC) were evaluated to screen for pathogens. Antimicrobial sensitivity, biofilm formation potential, and molecular analysis of MRSA were examined following standard guidelines.

RESULTS: Of the 1,156 samples, 882 (76%) were colonized by bacteria or candida. Among the infected patients, 69% were male and 36% were female with median age of 32 years. Staphylococcus aureus infected 39% (344/882) of CVCs in patients. Of the 59% (208/344) of patients with MRSA, 57% had community acquired MRSA and 43% had hospital acquired MRSA. Linezolid and vancomycin killed 100% of MRSA; resistance levels to fusidic acid, doxycycline, clindamycin, azithromycin, amikacin, trimethoprim-sulfamethoxazole, gentamycin, tobramycin, and ofloxacin were 21%, 42%, 66%, 68%, 72%, 85%, 95%, 97%, and 98% respectively. Strong biofilm was produced by 23% of samples, moderate by 27%, and weak by 50% of MRSA. The presence of adhesion genes, sdrC and sdrD (90%), eno (87%), fnbA (80%), clfA and sdrE (67%), fnbB, sdrD (61%), and cna (51%), in most MRSA samples suggested that the adhesion genes are associated with biofilm synthesis.

CONCLUSIONS: The superbug MRSA is a major cause of CVC-related infection. Antibiotic resistance to major classes of antibiotics and biofilm formation potential enhanced superbug MRSA virulence, leading to complicated infection. MRSA causes infection in hospitals, communities, and livestock.}, } @article {pmid30304123, year = {2018}, author = {Yang, Y and Li, W and Hou, B and Zhang, C}, title = {Quorum sensing LuxS/autoinducer-2 inhibits Enterococcus faecalis biofilm formation ability.}, journal = {Journal of applied oral science : revista FOB}, volume = {26}, number = {}, pages = {e20170566}, pmid = {30304123}, issn = {1678-7765}, mesh = {Analysis of Variance ; Bacterial Proteins/genetics/*physiology ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/genetics/*physiology ; Colony Count, Microbial ; Enterococcus faecalis/genetics/*growth & development ; Gene Knockout Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Plasmids ; Quorum Sensing/genetics/*physiology ; Real-Time Polymerase Chain Reaction ; Time Factors ; }, abstract = {OBJECTIVE: To investigate the relation between biofilm formation ability and quorum sensing gene LuxS/AI-2.

MATERIALS AND METHODS: Enterococcus faecalis (E. faecalis) standard strain ATCC 29212 was used in the study. Long flanking homology polymerase chain reaction method was used to build the LuxS gene knockout strain. Sequential culture turbidity measurement and CFU counting were used to assess the proliferation ability of E. faecalis after the depletion of LuxS. 96-well plate assay was used to quantify the biofilm formation ability; CLSM was used to observe the attached bacteria areas, while scanning electron microscopy (SEM) was performed to observe biofilm microstructure conditions.

RESULTS: LuxS gene knockout strains were successfully constructed and identified. The results showed that proliferation ability of E. faecalis was not affected by the depletion of the luxS gene, and the biofilm formation ability of ΔLuxS 29212 significantly decreased (P<0.05).

CONCLUSIONS: Collectively, our studies provide the LuxS gene's key role in controlling biofilm formation of E. faecalis, which presented a negative regulation, and furthermore, providing us a possible way to conquer the persistent apical periodontitis.}, } @article {pmid30304005, year = {2018}, author = {de Oliveira Junior, NM and Mendoza Marin, DO and Leite, ARP and Pero, AC and Klein, MI and Compagnoni, MA}, title = {Influence of the use of complete denture adhesives on microbial adhesion and biofilm formation by single- and mixed-species.}, journal = {PloS one}, volume = {13}, number = {10}, pages = {e0203951}, pmid = {30304005}, issn = {1932-6203}, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/physiology ; Colony Count, Microbial ; Dental Cements/*pharmacology ; Denture Retention/*methods ; Denture, Complete ; Lacticaseibacillus casei/drug effects/physiology ; Microscopy, Electron, Scanning ; Species Specificity ; Surface Properties ; }, abstract = {OBJECTIVES: To verify whether the Ultra Corega Cream and Corega Strip Denture Adhesive adhesives interfere in the microbial adhesion and biofilm formation by Candida albicans and Lactobacillus casei in single- and mixed-species settings, and observe whether synergistic or antagonistic relationships between these species occur.

METHODS: Specimens made from heat-polymerized acrylic resin (Lucitone 550) were fabricated (n = 144) with a circular shape and standardized roughness (3.0 μm ±0.3 Ra) and were divided into three groups: Without Adhesive (WA), with Ultra Corega Cream adhesive (CA) and Corega Strips adhesive (SA). These groups were divided into three subgroups each: C. albicans single-species, L. casei single-species and C. albicans with L. casei (mixed-species). Microbial adhesion and biofilm formation assays were performed in duplicate at four distinct experimental times (n = 8 per experimental condition). The amount of each microorganism on the surfaces of the specimens was observed by counting of the Colony Forming Units (CFU) per substrate. Additional specimens were characterized by Scanning Electron Microscopy (SEM), with 18 specimens being used in this analysis (n = 18), 2 per experimental condition (n = 2). Two-way ANOVA and Tukey's test for multiple comparisons were employed, using α≤0.05.

RESULTS: L. casei (mixed-species) adhered more on the WA substrate than the CA, while C. albicans (single- and mixed-species) adhered more on the SA. C. albicans, both single- and mixed-species adhered more than the L. casei (single- and mixed-species), regardless of the substrate. L. casei (single-species) formed more biofilm on the WA, but in its mixed cultivation, it had no difference of growth among the tested situations. C. albicans (single- and mixed-species) formed more biofilm on the SA than the CA, and the fungus formed more biofilm when compared to L. casei. In general, whenever a species was compared in its single- and mixed-species situation, no statistically significant difference was observed. SEM of biofilm formation assays demonstrated that L. casei single-species WA formed more biofilm than when the adhesives tested were used, and C. albicans (both single- and mixed-species) formed more biofilm on the SA than on the CA.

CONCLUSIONS: (1) The two denture adhesives tested increased the adhesion of C. albicans but not of L. casei; (2) biofilm formation by C. albicans (single- and mixed-species) was increased on the SA; (3) Relations of synergism or antagonism was not observed between the two microorganisms studied.}, } @article {pmid30303560, year = {2019}, author = {Busanello, FH and Petridis, X and So, MVR and Dijkstra, RJB and Sharma, PK and van der Sluis, LWM}, title = {Chemical biofilm removal capacity of endodontic irrigants as a function of biofilm structure: optical coherence tomography, confocal microscopy and viscoelasticity determination as integrated assessment tools.}, journal = {International endodontic journal}, volume = {52}, number = {4}, pages = {461-474}, doi = {10.1111/iej.13027}, pmid = {30303560}, issn = {1365-2591}, support = {//CNPq scholarship/ ; //Research Grant of the European Society of Endodontology (ESE)./ ; }, mesh = {Biofilms ; Chlorhexidine ; Microscopy, Confocal ; *Root Canal Irrigants ; *Tomography, Optical Coherence ; }, abstract = {AIM: To investigate the influence of biofilm structure on the biofilm removal capacity of endodontic irrigants and to study changes in the architecture of the remaining biofilms.

METHODOLOGY: Streptococcus oralis J22 and Actinomyces naeslundii T14V-J1 were cocultured under different growth conditions on saliva-coated hydroxyapatite discs. A constant depth film fermenter (CDFF) was used to grow steady-state 4-day biofilms. Biofilms were grown under static conditions for 4 and 10 days within a confined space. Twenty microlitres of 2% NaOCl, 2% Chlorhexidine (CHX), 17% Ethylene-diamine-tetra-acetic acid (EDTA) and buffer were applied statically on the biofilms for 60 s. Biofilm removal was evaluated with optical coherence tomography (OCT). Post-treated biofilms were assessed via low load compression testing (LLCT) and Confocal laser scanning microscopy (CLSM). Optical coherence tomography data were analysed through a two-way analysis of variance (ANOVA). Low load compression testing and CLSM data were analysed through one-way ANOVA and Dunnett's post hoc test. The level of significance was set at a < 0.05.

RESULTS: The initial biofilm structure affected the biofilm removal capacity of the irrigants. NaOCl demonstrated the greatest chemical efficacy against the biofilms and was significantly more effective on the static than the CDFF biofilms (P < 0.001). CHX was ineffective and caused a rearrangement of the biofilm structure. Ethylene-diamine-tetra-acetic acid exhibited a distinct removal effect only on the CDFF biofilms. Biofilm age influenced the structure of the remaining biofilms. The 4-day grown remaining biofilms had a significantly different viscoelastic pattern compared to the respective 10-day grown biofilms (P ≤ 0.01), especially in the NaOCl-treated group. Confocal laser scanning microscopy analysis confirmed the CHX-induced biofilm structural rearrangement.

CONCLUSIONS: Biofilm structure is an influential factor on the chemical efficacy of endodontic irrigants. Optical coherence tomography allows biofilm removal characteristics to be studied. NaOCl should remain the primary irrigant. Ethylene-diamine-tetra-acetic acid was effective against cell-rich/EPS-poor biofilms. Chlorhexidine did not remove biofilm, but rather rearranged its structure.}, } @article {pmid30300770, year = {2018}, author = {Emerenciano, NG and Botazzo Delbem, AC and Pessan, JP and Nunes, GP and Souza Neto, FN and de Camargo, ER and Danelon, M}, title = {In situ effect of fluoride toothpaste supplemented with nano-sized sodium trimetaphosphate on enamel demineralization prevention and biofilm composition.}, journal = {Archives of oral biology}, volume = {96}, number = {}, pages = {223-229}, doi = {10.1016/j.archoralbio.2018.09.019}, pmid = {30300770}, issn = {1879-1506}, mesh = {Animals ; Biofilms/*drug effects ; Cariostatic Agents/*chemistry/*pharmacology ; Cattle ; Cross-Over Studies ; Dose-Response Relationship, Drug ; Double-Blind Method ; Drug Combinations ; Fluorides, Topical/*pharmacology ; Hardness ; Healthy Volunteers ; Humans ; Hydrogen-Ion Concentration ; Nanoparticles ; Polyphosphates/*pharmacology ; Surface Properties ; Tooth Demineralization/*prevention & control ; Toothpastes/*chemistry/*pharmacology ; }, abstract = {OBJECTIVE: To evaluate the effect of a fluoride toothpaste containing nano-sized sodium trimetaphosphate (TMPnano) on enamel demineralization in situ and composition of the biofilm.

DESIGN: This crossover double-blind study consisted of four phases (seven days each) and 12 volunteers who wore oral appliances containing four enamel bovine blocks. The cariogenic challenge was performed by 30% sucrose solution (6x/day). The toothpaste treatments (3x/day) were as follows: no F/TMP/TMPnano (Placebo), 1100 ppm F (1100F), 1100F plus 3% micrometric or nano-sized TMP (1100F/TMP; 1100F/TMPnano). Percentage of surface hardness loss (%SH), and integrated loss of subsurface hardness (ΔKHN), as well as enamel calcium (Ca), phosphorus (P), and fluoride (F) were determined. Moreover, biofilm formed on the blocks were analyzed for F, Ca, P, and insoluble extracellular polysaccharide (EPS) concentrations. Data were analyzed using one-way ANOVA, repeated measures followed by Fisher LSD test (p < 0.001).

RESULTS: 1100F/TMPnano promoted the lowest %SH and ΔKHN among all groups (p < 0.001). Regarding the F concentrations in the enamel and in the biofilm, there were no significant differences between 1100 F and 1100 F/TMPnano, but significantly increased enamel Ca concentrations (p < 0.001). 1100F/TMPnano showed lower values of EPS concentration when compared with 1100F (∼80%) (p < 0.001).

CONCLUSION: 1100F/TMPnano promoted a greater protective effect against enamel demineralization and significantly affected the composition of biofilm formed in situ when compared to 1100F toothpaste.}, } @article {pmid30299554, year = {2019}, author = {Thompson, CM and Tischler, AH and Tarnowski, DA and Mandel, MJ and Visick, KL}, title = {Nitric oxide inhibits biofilm formation by Vibrio fischeri via the nitric oxide sensor HnoX.}, journal = {Molecular microbiology}, volume = {111}, number = {1}, pages = {187-203}, pmid = {30299554}, issn = {1365-2958}, support = {R35 GM119627/GM/NIGMS NIH HHS/United States ; GM119627/GM/NIGMS NIH HHS/United States ; GM119627/GF/NIH HHS/United States ; R01 GM114288/GM/NIGMS NIH HHS/United States ; IOS-1757297//NSF/International ; AI117262//National Institute of Allergy and Infectious Diseases/International ; GM114288/GF/NIH HHS/United States ; IOS-1757297//Division of Integrative Organismal Systems/International ; R21 AI117262/AI/NIAID NIH HHS/United States ; GM114288/GM/NIGMS NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/*drug effects/*growth & development ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects/*growth & development ; Gene Deletion ; Gene Expression ; Gene Expression Regulation, Bacterial/*drug effects ; Nitric Oxide/*metabolism ; Transcription, Genetic ; }, abstract = {Nitric oxide (NO) is an important defense molecule secreted by the squid Euprymna scolopes and sensed by the bacterial symbiont, Vibrio fischeri, via the NO sensor HnoX. HnoX inhibits colonization through an unknown mechanism. The genomic location of hnoX adjacent to hahK, a recently identified positive regulator of biofilm formation, suggested that HnoX may inhibit colonization by controlling biofilm formation, a key early step in colonization. Indeed, the deletion of hnoX resulted in early biofilm formation in vitro, an effect that was dependent on HahK and its putative phosphotransfer residues. An allele of hnoX that encodes a protein with increased activity severely delayed wrinkled colony formation. Control occurred at the level of transcription of the syp genes, which produce the polysaccharide matrix component. The addition of NO abrogated biofilm formation and diminished syp transcription, effects that required HnoX. Finally, an hnoX mutant formed larger symbiotic biofilms. This work has thus uncovered a host-relevant signal controlling biofilm and a mechanism for the inhibition of biofilm formation by V. fischeri. The study of V. fischeri HnoX permits us to understand not only host-associated biofilm mechanisms, but also the function of HnoX domain proteins as regulators of important bacterial processes.}, } @article {pmid30297525, year = {2019}, author = {Danforth, DR and Tang-Siegel, G and Ruiz, T and Mintz, KP}, title = {A Nonfimbrial Adhesin of Aggregatibacter actinomycetemcomitans Mediates Biofilm Biogenesis.}, journal = {Infection and immunity}, volume = {87}, number = {1}, pages = {}, pmid = {30297525}, issn = {1098-5522}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Aggregatibacter actinomycetemcomitans/*growth & development/metabolism ; Biofilms/*growth & development ; Fimbriae, Bacterial/genetics/metabolism ; Gene Deletion ; Humans ; }, abstract = {Periodontitis is an inflammatory disease caused by polymicrobial biofilms. The periodontal pathogen Aggregatibacter actinomycetemcomitans displays two proteinaceous surface structures, the fimbriae and the nonfimbrial extracellular matrix binding protein A (EmaA), as observed by electron microscopy. Fimbriae participate in biofilm biogenesis and the EmaA adhesins mediate collagen binding. However, in the absence of fimbriae, A. actinomycetemcomitans still retains the potential to form robust biofilms, suggesting that other surface macromolecules participate in biofilm development. Here, isogenic mutant strains lacking EmaA structures, but still expressing fimbriae, were observed to have reduced biofilm potential. In strains lacking both EmaA and fimbriae, biofilm mass was reduced by 80%. EmaA enhanced biofilm formation in different strains, independent of the fimbriation state or serotype. Confocal microscopy revealed differences in cell density within microcolonies between the EmaA positive and mutant strains. EmaA-mediated biofilm formation was found to be independent of the glycosylation state and the precise three-dimensional conformation of the protein, and thus this function is uncorrelated with collagen binding activity. The data suggest that EmaA is a multifunctional adhesin that utilizes different mechanisms to enhance bacterial binding to collagen and to enhance biofilm formation, both of which are important for A. actinomycetemcomitans colonization and subsequent infection.}, } @article {pmid30297365, year = {2018}, author = {Müsken, M and Pawar, V and Schwebs, T and Bähre, H and Felgner, S and Weiss, S and Häussler, S}, title = {Breaking the Vicious Cycle of Antibiotic Killing and Regrowth of Biofilm-Residing Pseudomonas aeruginosa.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {12}, pages = {}, pmid = {30297365}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/blood/pharmacokinetics/*pharmacology ; Biofilms/*drug effects/growth & development ; Colistin/blood/pharmacokinetics/*pharmacology ; Colonic Neoplasms/complications/*drug therapy/microbiology/pathology ; Colony Count, Microbial ; Disease Models, Animal ; Drug Administration Schedule ; Drug Dosage Calculations ; Drug Therapy, Combination/methods ; Female ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Pseudomonas Infections/complications/*drug therapy/microbiology/pathology ; Pseudomonas aeruginosa/*drug effects/growth & development/pathogenicity ; Tobramycin/blood/pharmacokinetics/*pharmacology ; Treatment Outcome ; }, abstract = {Biofilm-residing bacteria embedded in an extracellular matrix are protected from diverse physicochemical insults. In addition to the general recalcitrance of biofilm bacteria, high bacterial loads in biofilm-associated infections significantly diminish the efficacy of antimicrobials due to a low per-cell antibiotic concentration. Accordingly, present antimicrobial treatment protocols that have been established to serve the eradication of acute infections fail to clear biofilm-associated chronic infections. In the present study, we applied automated confocal microscopy on Pseudomonas aeruginosa to monitor dynamic killing of biofilm-grown bacteria by tobramycin and colistin in real time. We revealed that the time required for surviving bacteria to repopulate the biofilm could be taken as a measure for effectiveness of the antimicrobial treatment. It depends on the (i) nature and concentration of the antibiotic, (ii) duration of antibiotic treatment, (iii) application as monotherapy or combination therapy, and (iv) interval of drug administration. The vicious cycle of killing and repopulation of biofilm bacteria could also be broken in an in vivo model system by applying successive antibiotic dosages at intervals that do not allow full reconstitution of the biofilm communities. Treatment regimens that consider the important aspects of antimicrobial killing kinetics bear the potential to improve control of biofilm regrowth. This is an important and underestimated factor that is bound to ensure sustainable treatment success of chronic infections.}, } @article {pmid30297364, year = {2018}, author = {Heacock-Kang, Y and Sun, Z and Zarzycki-Siek, J and Poonsuk, K and McMillan, IA and Chuanchuen, R and Hoang, TT}, title = {Two Regulators, PA3898 and PA2100, Modulate the Pseudomonas aeruginosa Multidrug Resistance MexAB-OprM and EmrAB Efflux Pumps and Biofilm Formation.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {12}, pages = {}, pmid = {30297364}, issn = {1098-6596}, support = {R01 GM103580/GM/NIGMS NIH HHS/United States ; R21 AI123913/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Binding Sites ; Biofilms ; Drosophila melanogaster ; Gene Expression Regulation, Bacterial ; Male ; Membrane Proteins/genetics/metabolism ; Membrane Transport Proteins/genetics/metabolism ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Mutation ; Phenazines/metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/drug effects/pathogenicity/*physiology ; Repressor Proteins/genetics/metabolism ; }, abstract = {It is generally believed that the Pseudomonas aeruginosa biofilm matrix itself acts as a molecular sieve or sink that contributes to significant levels of drug resistance, but it is becoming more apparent that multidrug efflux pumps induced during biofilm growth significantly enhance resistance levels. We present here a novel transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux pumps in P. aeruginosa A mutant of this regulator significantly reduced the ability of P. aeruginosa to produce biofilm in vitro and affected its in vivo fitness and pathogenesis in Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux pumps and phenazine biosynthesis. Chromatin immunoprecipitation sequencing (ChIP-seq) identified its DNA binding sequences and confirmed that PA3898 directly interacts with promoter regions of four genes/operons, two of which are mexAB-oprM and phz2 Coimmunoprecipitation revealed a regulatory partner of PA3898 as PA2100, and both are required for binding to DNA in electrophoretic mobility shift assays. PA3898 and PA2100 were given the names MdrR1 and MdrR2, respectively, as novel repressors of the mexAB-oprM multidrug efflux operon and activators for another multidrug efflux pump, EmrAB. The interaction between MdrR1 and MdrR2 at the promoter regions of their regulons was further characterized via localized surface plasmon resonance and DNA footprinting. These regulators directly repress the mexAB-oprM operon, independent of its well-established MexR regulator. Mutants of mdrR1 and mdrR2 caused increased resistance to multiple antibiotics in P. aeruginosa, validating the significance of these newly discovered regulators.}, } @article {pmid30296655, year = {2018}, author = {Magi, G and Marini, E and Brenciani, A and Di Lodovico, S and Gentile, D and Ruberto, G and Cellini, L and Nostro, A and Facinelli, B and Napoli, E}, title = {Chemical composition of Pistacia vera L. oleoresin and its antibacterial, anti-virulence and anti-biofilm activities against oral streptococci, including Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {96}, number = {}, pages = {208-215}, doi = {10.1016/j.archoralbio.2018.09.013}, pmid = {30296655}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Chromatography, Gas ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pistacia/*chemistry ; Plant Extracts/*chemistry/*pharmacology ; Streptococcus mutans/*drug effects ; Virulence ; }, abstract = {OBJECTIVE: The aim of this study was to characterize the chemical composition of oleoresin of Pistacia vera L. and to determine its antimicrobial and anti-virulence activity versus selected oral streptococci.

DESIGN: A gaschromatografic analysis of the oleoresin was performed. The antimicrobial and anti-virulence activity of the oleoresin and its fractions was evaluated by the Minimum Inhibitory Concentration (MIC) and/or Minimum Bactericidal Concentration (MBC), biofilm production and haemolytic activity inhibition experiments.

RESULTS: The oleoresin MBCs were ≥1024 μg/mL for all tested strains; the neutral and acidic fraction MBCs ranged from 128 to 2048 μg/mL. Essential oil's MBCs (from 256 to 2048 μg/mL) were almost identical to MICs, suggesting a bactericidal effect. P. vera oleoresin at sub-lethal concentrations significantly reduced biofilm production by Streptococcus mutans (up to 49.4%) and by Streptococcus sanguinis (up to 71.2%). In addition, the acidic fraction showed a specific anti-biofilm activity against S. mutans (up to 41.3% reduction). A significant dose-dependent reduction in the haemolytic activity of S. mutans (up to 65.9%) and of S. anginosus (up to 78.3%) was observed after growth in the presence of oleoresin at sub-lethal concentrations. The acidic fraction reduced haemolytic activity (up to 54.3% at 64 μg/mL) of S. mutans only.

CONCLUSIONS: Given the anti-virulence activity of the P. vera oleoresin and its acidic fraction against S. mutans, our findings suggest their potential use in oral hygiene. These data represent the first step in the exploitation of P. vera L. oleoresin.}, } @article {pmid30296552, year = {2018}, author = {Ye, WH and Fan, B and Purcell, W and Meghil, MM and Cutler, CW and Bergeron, BE and Ma, JZ and Tay, FR and Niu, LN}, title = {Anti-biofilm efficacy of root canal irrigants against in-situ Enterococcus faecalis biofilms in root canals, isthmuses and dentinal tubules.}, journal = {Journal of dentistry}, volume = {79}, number = {}, pages = {68-76}, doi = {10.1016/j.jdent.2018.10.002}, pmid = {30296552}, issn = {1879-176X}, mesh = {Biofilms ; Dental Pulp Cavity ; *Enterococcus faecalis ; Hydrogen Peroxide ; *Root Canal Irrigants ; Sodium Hypochlorite ; }, abstract = {OBJECTIVE: To investigate the anti-biofilm efficacy of root canal irrigants in canal spaces, isthmi and dentinal tubules of root canals ex vivo.

METHODS: Fifty-one single-rooted premolars, each containing an isthmus, were instrumented, autoclaved and inoculated with Enterococcus faecalis for 4 weeks. One specimen was sectioned for bacteria-specific staining to confirm the presence of biofilms using light microscopiy. The remaining specimens were randomly divided to five groups: (1) 0.9% NaCl, (2) SilverSol/H2O2, (3) HYBENX, (4) QMix 2 in1, (5) 6% NaOCl. Bacterial sampling was performed before (S1) and after (S2) canal irrigation. Diluted bacteria suspension was cultured for 48 h for counting the colony forming units (CFU). Percentages of dead bacteria and biofilm thickness were evaluated by confocal laser scanning microscopy (CLSM). Metabolic activity, lactic acid and polysaccharide synthesis of E. faecalis derived from S2 samples were analysed.

RESULTS: The percentages of dead bacteria were significantly affected by the factor "irrigant" (p < 0.001) and the factor "location" (p = 0.017). The percentages of dead bacteria in the isthmi and canals were both in the ordor: NaCl < SilverSol/H2O2 < HYBENX < QMix 2 in1 < NaOCl (p < 0.05). Only 6% NaOCl disrupted biofilms and significantly reduced their thickness. The CFU, metabolic activity, polysaccharide and lactic acid production of E. faecalis were all reduced by the disinfecting solutions.

CONCLUSIONS: SilverSol/H2O2 and HYBENX were less adept than QMix 2 in1 at killing biofilm bacteria in root canals. None of these antibacterial irrigants were effective, compared with 6% NaOCl, in disrupting biofilms.

CLINICAL SIGNIFICANCE: There is advantage in using HYBENX or QMix 2 in1 to kill intratubular bacteria biofilms because of their capability in removing the inorganic component of the smear layer. SilverSol/H2O2 requires extra time to eradicate intratubular biofilms upon removal of the organic and inorganic components of the smear layer by other root canal irrigants.}, } @article {pmid30296253, year = {2018}, author = {Zarnowski, R and Sanchez, H and Covelli, AS and Dominguez, E and Jaromin, A and Bernhardt, J and Mitchell, KF and Heiss, C and Azadi, P and Mitchell, A and Andes, DR}, title = {Candida albicans biofilm-induced vesicles confer drug resistance through matrix biogenesis.}, journal = {PLoS biology}, volume = {16}, number = {10}, pages = {e2006872}, pmid = {30296253}, issn = {1545-7885}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/pathogenicity/*physiology ; Cryoelectron Microscopy ; Drug Resistance, Fungal ; Endosomal Sorting Complexes Required for Transport/genetics/physiology ; Extracellular Polymeric Substance Matrix/drug effects/physiology/ultrastructure ; Extracellular Vesicles/drug effects/physiology/ultrastructure ; Fungal Proteins/metabolism ; Humans ; Lipid Metabolism ; Microbial Interactions/drug effects/physiology ; Microscopy, Electron, Scanning ; Models, Biological ; Mutation ; Proteome/metabolism ; }, abstract = {Cells from all kingdoms of life produce extracellular vesicles (EVs). Their cargo is protected from the environment by the surrounding lipid bilayer. EVs from many organisms have been shown to function in cell-cell communication, relaying signals that impact metazoan development, microbial quorum sensing, and pathogenic host-microbe interactions. Here, we have investigated the production and functional activities of EVs in a surface-associated microbial community or biofilm of the fungal pathogen Candida albicans. Crowded communities like biofilms are a context in which EVs are likely to function. Biofilms are noteworthy because they are encased in an extracellular polymeric matrix and because biofilm cells exhibit extreme tolerance to antimicrobial compounds. We found that biofilm EVs are distinct from those produced by free-living planktonic cells and display strong parallels in composition to biofilm matrix material. The functions of biofilm EVs were delineated with a panel of mutants defective in orthologs of endosomal sorting complexes required for transport (ESCRT) subunits, which are required for normal EV production in diverse eukaryotes. Most ESCRT-defective mutations caused reduced biofilm EV production, reduced matrix polysaccharide levels, and greatly increased sensitivity to the antifungal drug fluconazole. Matrix accumulation and drug hypersensitivity of ESCRT mutants were reversed by addition of wild-type (WT) biofilm EVs. Vesicle complementation showed that biofilm EV function derives from specific cargo proteins. Our studies indicate that C. albicans biofilm EVs have a pivotal role in matrix production and biofilm drug resistance. Biofilm matrix synthesis is a community enterprise; prior studies of mixed cell biofilms have demonstrated extracellular complementation. Therefore, EVs function not only in cell-cell communication but also in the sharing of microbial community resources.}, } @article {pmid30295328, year = {2019}, author = {Swimberghe, RCD and De Clercq, A and De Moor, RJG and Meire, MA}, title = {Efficacy of sonically, ultrasonically and laser-activated irrigation in removing a biofilm-mimicking hydrogel from an isthmus model.}, journal = {International endodontic journal}, volume = {52}, number = {4}, pages = {515-523}, doi = {10.1111/iej.13024}, pmid = {30295328}, issn = {1365-2591}, mesh = {Biofilms ; *Dental Pulp Cavity ; Hydrogels ; *Root Canal Irrigants ; Root Canal Preparation ; Root Canal Therapy ; Therapeutic Irrigation ; }, abstract = {AIM: To evaluate the efficacy of sonically, ultrasonically and laser-activated irrigation (LAI) in removing a biofilm-mimicking hydrogel from the isthmus in a root canal model.

METHODOLOGY: Transparent resin blocks containing two standardized root canals (apical diameter of 0.3 mm, 6% taper, 16 mm long, with a coronal reservoir) connected by an isthmus (0.15 mm wide, 2 mm high) were used as the test model. The isthmus was filled with a hydrogel-containing dentine debris. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n = 20): EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) with an Irrisafe 25 mm length, size 25 file and LAI with a 2940 nm Er:YAG-laser (20 Hz, 50 μs, 20 mJ, PIPS tip at the canal entrance). All protocols were executed for 3 × 20 s. Needle irrigation (NI) with a 27G needle served as the control. Standardized images of the isthmus were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Welch anova (P ≤ 0.05).

RESULTS: Hydrogel removal was greatest in the LAI group (90.2%) and was significantly greater than that with UAI, EA and NI (P ≤ 0.014), but not significantly different from Eddy (P = 0.498). Hydrogel removal with Eddy (85.9%) was significantly greater than that with NI and EA (P < 0.05), but not significantly different from UAI (P = 0.07). There was no significant difference between the NI and EA groups (P = 1).

CONCLUSIONS: Laser-activated irrigation and Eddy resulted in the greatest hydrogel removal and performed better than EA and UAI. The effect of LAI was also not dependent on deep intracanal tip placement.}, } @article {pmid30295162, year = {2019}, author = {Ali, Q}, title = {Non-conventional therapeutic technique to replace CRISPR bacteria from biofilm by inducible lysogen.}, journal = {Journal of biological dynamics}, volume = {13}, number = {sup1}, pages = {151-178}, doi = {10.1080/17513758.2018.1527958}, pmid = {30295162}, issn = {1751-3766}, mesh = {Algorithms ; Bacteria/*genetics ; *Biofilms/growth & development ; Clustered Regularly Interspaced Short Palindromic Repeats/*genetics ; Lysogeny/*genetics ; Models, Biological ; }, abstract = {Bacteriophage can be an effective means of regulating bacterial populations when conditions allow phage invasion of bacterial colonies. Phage can either infect and lyse a host cell, or insert their DNA into the host cell genome; the latter process is called lysogeny. The clustered regularly interspaced short palindromic repeat (CRISPR) system, linked with CRISPR-associated (Cas) genes, is a regulatory system present in a variety of bacteria which confers immunity against bacteriophage. Studies of the group behaviour of bacteria with CRISPR/Cas systems have provided evidence that CRISPR in lysogenized bacteria can cause an inability to form biofilm. This allows CRISPR-immune bacteria in biofilms to effectively resist phage therapy. Our recent work has described a potential therapeutic technique to eradicate CRISPR-immune bacteria from a biofilm by a continuous influx of lysogens carrying an identical phage sequence. However, this model predicted that the CRISPR-immune population could persist for long times before eradication. Our current focus is on the use of diverse lysogens against CRISPR-capable bacterial populations. The goal of this work is to find a suitable strategy which can eradicate bacteria with a CRISPR system through the influx of finite amounts of distinct lysogens over fixed intervals.}, } @article {pmid30292821, year = {2018}, author = {Pickering, DS and Wilcox, MH and Chilton, CH}, title = {Biofilm-derived spores of Clostridioides (Clostridium) difficile exhibit increased thermotolerance compared to planktonic spores.}, journal = {Anaerobe}, volume = {54}, number = {}, pages = {169-171}, doi = {10.1016/j.anaerobe.2018.10.003}, pmid = {30292821}, issn = {1095-8274}, mesh = {*Biofilms ; Clostridioides difficile/chemistry/growth & development/*physiology/ultrastructure ; Hot Temperature ; Microscopy, Electron, Transmission ; Spores, Bacterial/*chemistry/growth & development/physiology/ultrastructure ; Thermotolerance ; }, abstract = {Biofilm-derived spores of strains of four ribotypes (001, 020, 027 & 078) of Clostridioides (Clostridium) difficile were found to exhibit increased thermotolerance compared to spores produced in planktonic culture. In addition, 'thick' and 'thin' exosporium morphotypes described previously were visualised by electron microscopy in both biofilm and planktonic spores.}, } @article {pmid30292689, year = {2019}, author = {Jiang, Y and Zeng, RJ}, title = {Bidirectional extracellular electron transfers of electrode-biofilm: Mechanism and application.}, journal = {Bioresource technology}, volume = {271}, number = {}, pages = {439-448}, doi = {10.1016/j.biortech.2018.09.133}, pmid = {30292689}, issn = {1873-2976}, mesh = {Bioelectric Energy Sources ; *Biofilms ; *Electrodes ; Electrons ; }, abstract = {The extracellular electron transfer (EET) between microorganisms and electrodes forms the basis for microbial electrochemical technology (MET), which recently have advanced as a flexible platform for applications in energy and environmental science. This review, for the first time, focuses on the electrode-biofilm capable of bidirectional EET, where the electrochemically active bacteria (EAB) can conduct both the outward EET (from EAB to electrodes) and the inward EET (from electrodes to EAB). Only few microorganisms are tested in pure culture with the capability of bidirectional EET, however, the mixed culture based bidirectional EET offers great prospects for biocathode enrichment, pollutant complete mineralization, biotemplated material development, pH stabilization, and bioelectronic device design. Future efforts are necessary to identify more EAB capable of the bidirectional EET, to balance the current density, to evaluate the effectiveness of polarity reversal for biocathode enrichment, and to boost the future research endeavors of such a novel function.}, } @article {pmid30292385, year = {2018}, author = {Heidari, H and Hadadi, M and Sedigh Ebrahim-Saraie, H and Mirzaei, A and Taji, A and Hosseini, SR and Motamedifar, M}, title = {Characterization of virulence factors, antimicrobial resistance patterns and biofilm formation of Pseudomonas aeruginosa and Staphylococcus spp. strains isolated from corneal infection.}, journal = {Journal francais d'ophtalmologie}, volume = {41}, number = {9}, pages = {823-829}, doi = {10.1016/j.jfo.2018.01.012}, pmid = {30292385}, issn = {1773-0597}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Corneal Ulcer/drug therapy/*microbiology ; DNA, Bacterial/analysis ; *Drug Resistance, Multiple, Bacterial/genetics ; Eye Infections, Bacterial/drug therapy/*microbiology ; Humans ; Iran ; Keratitis/drug therapy/microbiology ; Microbial Sensitivity Tests ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/genetics/isolation & purification/pathogenicity/*physiology ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus/genetics/isolation & purification/pathogenicity/*physiology ; Virulence Factors/*analysis/genetics ; }, abstract = {INTRODUCTION: Infectious keratitis is a serious ocular infection that can lead to severe visual impairment and blindness. Bacterial pathogens are responsible for nearly half of infectious keratitis cases. This study was performed to determine the virulence factors, antimicrobial resistance patterns, and biofilm formation ability of Pseudomonas aeruginosa and Staphylococcus spp. strains isolated from corneal infections.

METHODS: A total of 56 corneal scraping samples were collected over 8 months. P. aeruginosa and staphylococcal strains were identified by phenotypic and genotypic methods. Determination of multidrug resistance was performed according to its definition of multidrug resistance (MDR). Detection of antimicrobial resistance genes and determinants of virulence were also performed using standard procedures. Biofilm formation ability of the isolates was determined by colorimetric microtitration plate assay and Modified Congo red agar (MCRA).

RESULTS: In the present study, P. aeruginosa, MSSA, MRSA, MS-CoNS and MR-CoNS strains were isolated from corneal infections. Multidrug resistance was observed in 42.9% and 57.1% of P. aeruginosa and Staphylococcus spp., respectively. The most frequent virulence genes among P. aeruginosa strains were exoA and exoS (100%) followed by exoU (71.4%) and lasB (28.6%). All the P. aeruginosa isolates were biofilm producers and carried the algD gene (100%). All staphylococcal strains were negative for pvl gene amplification. Biofilm formation was also observed in 4 (57.1%) isolates. Both icaA and icaD genes were detected in the biofilm producers.

CONCLUSION: Our results indicated that P. aeruginosa and Staphylococcus spp. were the most prevalent bacterial agents that cause corneal infections. However, their virulence traits and biofilm formation ability were noteworthy.}, } @article {pmid30291415, year = {2019}, author = {Zhai, S and Zhao, Y and Ji, M and Qi, W}, title = {A dicyclic-type electrode-based biofilm reactor for simultaneous nitrate and Cr(VI) reduction.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {1}, pages = {167-172}, doi = {10.1007/s00449-018-2020-2}, pmid = {30291415}, issn = {1615-7605}, support = {Project No. 21507101, China//National Natural Science Foundation of China/ ; Project No.15JCQNJC08700, China//Tianjin Research Program of Application Foundation and Advanced Technology/ ; }, mesh = {*Biofilms ; *Bioreactors ; Biotechnology/*methods ; Chromates/chemistry ; Chromium/*chemistry ; Denitrification ; *Electrodes ; Equipment Design ; Groundwater ; Heterotrophic Processes ; Nitrates/*chemistry ; Nitrogen/chemistry ; Sewage ; Water Pollutants, Chemical ; Water Purification ; }, abstract = {A dicyclic-type electrode-based biofilm-electrode reactor (BER) was investigated for simultaneous removal of nitrate and Cr(VI). In the absence of Cr(VI), almost complete denitrification of 50 mg/L NO3[-]-N was achieved at a very low C/N ratio of 0.8 with the optimal current of 50 mA. Cr(VI) was removed by biological reduction and co-precipitation when Cr(VI) was taken as the only electron acceptor, and the removal efficiencies of Cr(VI) were 99.8%. In the coexistent system of nitrate and Cr(VI), nitrate removal was the result of the cooperation of hydrogenotrophic denitrification and heterotrophic denitrification. The methanol and H2 were also used as electron donors for biological reduction Cr(VI). The denitrification process was slightly inhibited by 1.00 mg/L Cr(VI) and 94.15% removal efficiency was achieved at current = 50 mA and HRT = 8 h. The present results show that the biofilm-electrode reactor is an effective way to simultaneous remove co-contaminants.}, } @article {pmid30291231, year = {2018}, author = {Chu, EK and Kilic, O and Cho, H and Groisman, A and Levchenko, A}, title = {Self-induced mechanical stress can trigger biofilm formation in uropathogenic Escherichia coli.}, journal = {Nature communications}, volume = {9}, number = {1}, pages = {4087}, pmid = {30291231}, issn = {2041-1723}, mesh = {Anti-Bacterial Agents ; Biofilms/*growth & development ; Cell Proliferation ; Drug Tolerance ; Pressure ; Stress, Mechanical ; Uropathogenic Escherichia coli/*physiology ; }, abstract = {Bacterial biofilms represent an important medical problem; however, the mechanisms of the onset of biofilm formation are poorly understood. Here, using new controlled methods allowing high-throughput and reproducible biofilm growth, we show that biofilm formation is linked to self-imposed mechanical stress. In growing uropathogenic Escherichia coli colonies, we report that mechanical stress can initially emerge from the physical stress accompanying colony confinement within micro-cavities or hydrogel environments reminiscent of the cytosol of host cells. Biofilm formation can then be enhanced by a nutrient access-modulated feedback loop, in which biofilm matrix deposition can be particularly high in areas of increased mechanical and biological stress, with the deposited matrix further enhancing the stress levels. This feedback regulation can lead to adaptive and diverse biofilm formation guided by the environmental stresses. Our results suggest previously unappreciated mechanisms of the onset and progression of biofilm growth.}, } @article {pmid30290269, year = {2018}, author = {Mizdal, CR and Stefanello, ST and Nogara, PA and Antunes Soares, FA and de Lourenço Marques, L and de Campos, MMA}, title = {Molecular docking, and anti-biofilm activity of gold-complexed sulfonamides on Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {125}, number = {}, pages = {393-400}, doi = {10.1016/j.micpath.2018.10.004}, pmid = {30290269}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/chemistry/metabolism ; Biofilms/*drug effects ; Gold/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; Molecular Docking Simulation ; Protein Binding ; Pseudomonas aeruginosa/*drug effects/physiology ; Sulfonamides/chemistry/*pharmacology ; Trans-Activators/chemistry/metabolism ; }, abstract = {The antibacterial activity of sulfadiazine Au-PPh3, sulfadiazine Ph2P-Au-Au-PPh2, sulfamethoxazole Au-PPh3, sulfamethoxazole Ph2P-Au-Au-PPh2, sulfamethoxazole Au-PPh3 were tested against Pseudomonas aeruginosa. The antibacterial activity of sulfonamide was tested against P. aeruginosa through the MIC assay, quantitative analysis of biofilm inhibition and observation of biofilm formation with fluorescence microscopy. Besides, the compounds presented remarkable inhibition of P. aeruginosa biofilm formation. Furthermore, molecular docking was performed to identify the key structural features of these compounds with the binding site of the LasR receptor.}, } @article {pmid30290265, year = {2018}, author = {Sharma, D and Khan, AU}, title = {Role of cell division protein divIVA in Enterococcus faecalis pathogenesis, biofilm and drug resistance: A future perspective by in silico approaches.}, journal = {Microbial pathogenesis}, volume = {125}, number = {}, pages = {361-365}, doi = {10.1016/j.micpath.2018.10.001}, pmid = {30290265}, issn = {1096-1208}, mesh = {Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Cell Cycle Proteins/chemistry/genetics/*metabolism ; *Cell Division ; Computational Biology ; DNA, Bacterial/chemistry/metabolism ; DNA-Binding Proteins/chemistry/genetics/metabolism ; *Drug Resistance, Bacterial ; Enterococcus faecalis/*drug effects/genetics/*pathogenicity/physiology ; Gram-Positive Bacterial Infections/microbiology/pathology ; Molecular Docking Simulation ; Protein Binding ; Protein Interaction Mapping ; Protein Interaction Maps ; Virulence ; Virulence Factors/chemistry/genetics/metabolism ; }, abstract = {Antibiotics resistance is the major problem in clinical settings which leads to the emergence of drug resistant bacteria. Biofilm formation is one of the grounds for the emergence of antibiotics resistant strains of Enterococcus faecalis. Our group previously reported in a comparative proteomic study of biofilm and planktonic state of E. faecalis that cell division protein divIVA was two folds overexpressed in biofilm state as compared to planktonic one and suggested its involvement in biofilm formation and antibiotics resistance. In this in silico study molecular docking showed that DNA bind to the conserved amino acid residues of divIVA domain and suggested that divIVA possibly secretes DNA into extra polymeric substance (EPS) which is the part of biofilm. We also performed the STRING analysis of cell division protein divIVA and predicted their interactive partners {cell division proteins/divisome complex (ftsZ, ftsA, divIV, ftsL, & gpsB), hypothetical proteins (sepF, EF_0261, EF_1000, EF_0998, EF_1006 & EF_1040), isoleucyl-tRNA synthetase (ileS), septation ring formation regulator (ezrA), S4 domain-containing protein (EF_1001), rod shape-determining protein (mreC), UDP-N-acetylmuramoyl-L-alanyl-d-glutamate synthetase (murD), UDP-diphospho-muramoyl-pentapeptide beta-N- acetylglucosaminyltransferase (murG), Lipoprotein signal peptidase (lspA), adenylate kinase (adk) and DNA-binding response regulator (vicR)} . We suggest that cumulatively divIVA and its interactive partners might be directly or indirectly involved in E. faecalis cell division, growth, biofilm formation, virulence and resistance.}, } @article {pmid30288586, year = {2018}, author = {Kang, J and Liu, L and Wu, X and Sun, Y and Liu, Z}, title = {Effect of thyme essential oil against Bacillus cereus planktonic growth and biofilm formation.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {23}, pages = {10209-10218}, pmid = {30288586}, issn = {1432-0614}, support = {31301472//National Natural Science Foundations of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacillus cereus/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Cyclohexane Monoterpenes ; Cymenes ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Monoterpenes/pharmacology ; Oils, Volatile/*pharmacology ; Thymol/pharmacology ; Thymus Plant/*chemistry ; }, abstract = {The objective of this study was to determine the effect of thyme essential oil (TEO) on the planktonic growth and biofilm formation of Bacillus cereus (B. cereus). GC-MS analysis of TEO allowed the detection of 13 compounds, and the major constituents were p-cymene (29.7%), thymol (23.73%), γ-terpinene (16.21%), and 1,8-cineole (9.74%). TEO exhibited a minimum inhibitory concentration (MIC) value against planktonic B. cereus of 0.25 mg/mL. The potent effect of TEO to inhibit the growth of planktonic B. cereus was due to cell membrane damage, as evidenced by reduced cell viability, protein changes, decreased intracellular ATP concentration, increased extracellular ATP concentration and cell membrane depolarization, and cellular morphological changes. In addition, TEO exerted a significant inhibitory effect on B. cereus biofilm formation, as confirmed by environmental scanning electron microscopic images. These findings suggested that TEO has the potential to be developed as a natural food additive to control foodborne contamination associated with B. cereus and its biofilm.}, } @article {pmid30288179, year = {2018}, author = {Parrino, B and Diana, P and Cirrincione, G and Cascioferro, S}, title = {Bacterial Biofilm Inhibition in the Development of Effective Anti-Virulence Strategy.}, journal = {The open medicinal chemistry journal}, volume = {12}, number = {}, pages = {84-87}, pmid = {30288179}, issn = {1874-1045}, } @article {pmid30283433, year = {2018}, author = {Dobay, O and Laub, K and Stercz, B and Kéri, A and Balázs, B and Tóthpál, A and Kardos, S and Jaikumpun, P and Ruksakiet, K and Quinton, PM and Zsembery, Á}, title = {Bicarbonate Inhibits Bacterial Growth and Biofilm Formation of Prevalent Cystic Fibrosis Pathogens.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2245}, pmid = {30283433}, issn = {1664-302X}, abstract = {We investigated the effects of bicarbonate on the growth of several different bacteria as well as its effects on biofilm formation and intracellular cAMP concentration in Pseudomonas aeruginosa. Biofilm formation was examined in 96-well plates, with or without bicarbonate. The cAMP production of bacteria was measured by a commercial assay kit. We found that NaHCO3 (100 mmol l[-1]) significantly inhibited, whereas NaCl (100 mmol l[-1]) did not influence the growth of planktonic bacteria. MIC and MBC measurements indicated that the effect of HCO 3 - is bacteriostatic rather than bactericidal. Moreover, NaHCO3 prevented biofilm formation as a function of concentration. Bicarbonate and alkalinization of external pH induced a significant increase in intracellular cAMP levels. In conclusion, HCO 3 - impedes the planktonic growth of different bacteria and impedes biofilm formation by P. aeruginosa that is associated with increased intracellular cAMP production. These findings suggest that aerosol inhalation therapy with HCO 3 - solutions may help improve respiratory hygiene in patients with cystic fibrosis and possibly other chronically infected lung diseases.}, } @article {pmid30281855, year = {2019}, author = {Li, B and Maezato, Y and Kim, SH and Kurihara, S and Liang, J and Michael, AJ}, title = {Polyamine-independent growth and biofilm formation, and functional spermidine/spermine N-acetyltransferases in Staphylococcus aureus and Enterococcus faecalis.}, journal = {Molecular microbiology}, volume = {111}, number = {1}, pages = {159-175}, doi = {10.1111/mmi.14145}, pmid = {30281855}, issn = {1365-2958}, support = {High Risk High Impact Grant to AJM//University of Texas Southwestern Medical Center/International ; SH1000//University of Sheffield/International ; //University of Colorado/International ; //UT Southwestern/International ; }, mesh = {Acetylation ; Acetyltransferases/*metabolism ; Biofilms/*growth & development ; Enterococcus faecalis/*enzymology/*growth & development ; Protein Processing, Post-Translational ; Spermidine/analogs & derivatives/*metabolism ; Spermine/metabolism ; Staphylococcus aureus/*enzymology/*growth & development ; }, abstract = {Polyamines such as spermidine and spermine are primordial polycations that are ubiquitously present in the three domains of life. We have found that Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis have lost either all or most polyamine biosynthetic genes, respectively, and are devoid of any polyamine when grown in polyamine-free media. In contrast to bacteria such as Pseudomonas aeruginosa, Campylobacter jejuni and Agrobacterium tumefaciens, which absolutely require polyamines for growth, S. aureus and E. faecalis grow normally over multiple subcultures in the absence of polyamines. Furthermore, S. aureus and E. faecalis form biofilms normally without polyamines, and exogenous polyamines do not stimulate growth or biofilm formation. High levels of external polyamines, including norspermidine, eventually inhibit biofilm formation through inhibition of planktonic growth. We show that spermidine/spermine N-acetyltransferase (SSAT) homologues encoded by S. aureus USA300 and E. faecalis acetylate spermidine, spermine and norspermidine, that spermine is the more preferred substrate, and that E. faecalis SSAT is almost as efficient as human SSAT with spermine as substrate. The polyamine auxotrophy, polyamine-independent growth and biofilm formation, and presence of functional polyamine N-acetyltransferases in S. aureus and E. faecalis represent a new paradigm for bacterial polyamine biology.}, } @article {pmid30280048, year = {2018}, author = {Mancuso, R and Chinnici, J and Tsou, C and Busarajan, S and Munnangi, R and Maddi, A}, title = {Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5685}, pmid = {30280048}, issn = {2167-8359}, abstract = {BACKGROUND: Candida albicans is a commensal fungus that inhabits the oral mucosal surface and causes oral and systemic candidiasis. Oral candidiasis most commonly occurs in patients with AIDS, denture wearers and newborn children. Systemic candidiasis occurs mainly in immunocompromised patients and patients admitted to hospitals for prolonged periods. C. albicans homologous genes, DFG5 and DCW1, encode for two closely related cell wall proteins with putative glycosyltransferase enzyme activity and C-terminal GPI-anchors. Past studies have shown that individual DFG5 and DCW1 mutations are viable but simultaneous deletion of DFG5 and DCW1 in C. albicans results in lethality. However, the exact functions of these cell wall based enzymes, which represent potential drug targets, are not understood.

METHODS: C. albicans DFG5/DCW1 heterologous and conditional double mutant strains were assessed for growth and biofilm formation in comparison to wild type and parental strains. Cell wall and heat stress susceptibility of the mutant and control strains were assessed using agar spotting assays. Growth was assessed under normal and osmotic stress conditions along with light microscopy imaging. Biofilm dry weight and microscopic imaging analysis of biofilms was performed. Hypha formation in response to serum was analyzed using light microscopy imaging. Western blot analysis of mutant strains and control strains was performed to assess Hog1 basal levels and phosphorylation status.

RESULTS: Analysis of the heterologous mutants indicated that Dfg5p is more important for growth while Dcw1p appeared to play a role in cell wall integrity response. The conditional double mutant was observed to be less resistant to cell wall stress. However, growth of the mutants was similar under control and osmotic stress conditions. The mutants were also able to grow similar to wild type under heat stress. Biofilm formation was reduced in the mutants where DFG5 was deleted or suppressed. Hyphal morphogenesis was reduced although germ tube formation was observed in the biofilms of the mutant strains. Basal Hog1 protein levels were reduced or absent in the DFG5 and DCW1 mutants. However, osmotic stress was able to induce Hog1 protein levels comparable to wild type. Hog1 phosphorylation appeared to be slightly reduced although not significantly. In addition to biofilm assays, serum dose response imaging analysis indicated that hyphae formation in DFG5 and DCW1 mutants was defective.

CONCLUSIONS: These data indicate that DFG5 and DCW1 are required for hyphal morphogenesis and biofilm formation in C. albicans. These functions may be regulated via basal Hog1 MAPK which is required for transcriptional regulation of chitin synthesis.}, } @article {pmid30279343, year = {2018}, author = {Marc, G and Araniciu, C and Oniga, SD and Vlase, L and Pîrnău, A and Duma, M and Măruțescu, L and Chifiriuc, MC and Oniga, O}, title = {New N-(oxazolylmethyl)-thiazolidinedione Active against Candida albicans Biofilm: Potential Als Proteins Inhibitors.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {10}, pages = {}, pmid = {30279343}, issn = {1420-3049}, support = {PCD 7690/68/15.04.2016//"Iuliu Hatieganu" University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; PCD 5200/59/01.03.2017//"Iuliu Hatieganu" University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; PCD 3067/4/01.02.2018//"Iuliu Hatieganu" University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; }, mesh = {Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development/pathogenicity ; Cell Adhesion/drug effects ; Fungal Proteins/*antagonists & inhibitors/chemistry ; Humans ; Thiazolidinediones/chemical synthesis/*chemistry/isolation & purification ; }, abstract = {C. albicans is the most frequently occurring fungal pathogen, and is becoming an increasing public health problem, especially in the context of increased microbial resistance. This opportunistic pathogen is characterized by a versatility explained mainly by its ability to form complex biofilm structures that lead to enhanced virulence and antibiotic resistance. In this context, a review of the known C. albicans biofilm formation inhibitors were performed and a new N-(oxazolylmethyl)-thiazolidinedione scaffold was constructed. 16 new compounds were synthesized and characterized in order to confirm their proposed structures. A general antimicrobial screening against Gram-positive and Gram-negative bacteria, as well as fungi, was performed and revealed that the compounds do not have direct antimicrobial activity. The anti-biofilm activity evaluation confirmed the compounds act as selective inhibitors of C. albicans biofilm formation. In an effort to substantiate this biologic profile, we used in silico investigations which suggest that the compounds could act by binding, and thus obstructing the functions of, the C. albicans Als surface proteins, especially Als1, Als3, Als5 and Als6. Considering the well documented role of Als1 and Als3 in biofilm formation, our new class of compounds that target these proteins could represent a new approach in C. albicans infection prevention and management.}, } @article {pmid30279094, year = {2018}, author = {Hu, J and Zhang, H and Zhou, S and Li, W and He, ZG}, title = {Characterization of a novel regulatory pathway for mannitol metabolism and its coordination with biofilm formation in Mycobacterium smegmatis.}, journal = {Journal of genetics and genomics = Yi chuan xue bao}, volume = {45}, number = {9}, pages = {477-488}, doi = {10.1016/j.jgg.2018.06.007}, pmid = {30279094}, issn = {1673-8527}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/growth & development ; Gene Expression Regulation, Bacterial ; Mannitol/*metabolism ; Multigene Family ; Mycobacterium smegmatis/*physiology ; Operon ; Transcription Factors/genetics/metabolism ; }, abstract = {Biofilm formation has been implicated to be tightly regulated in bacteria. Mycobacterial species possess a unique cell-wall structure; however, the underlying regulation mechanism for their biofilm formation remains largely unclear. In this study, we characterized a hypothetical mannitol metabolism and transportation gene cluster (Ms5571-Ms5576), designated as mmt operon, whose expression significantly contributes to the biofilm formation in Mycobacterium smegmatis. We showed that in the operon the Ms5575 gene encodes a GntR-like transcriptional repressor and the Ms5576 gene encodes a mannitol 2-dehydrogenase which can produce D-mannitol from D-mannose. Strikingly, the D-mannitol molecule can derepress the negative regulation of Ms5575 on the mmt operon to stimulate the operon's expression. Consistently, addition of D-mannitol into the medium can obviously induce mycobacterial biofilm formation. Furthermore, we found that Ms0179 positively regulates the mmt operon through its downstream regulator Ms0180. Ms0180 directly binds the mmt operon to positively regulate its expression. Both Ms0179 and Ms0180 significantly affect the mycobacterial biofilm formation. Taken together, we explored a regulatory pathway for the mannitol metabolism and its coordination with the biofilm formation in M. smegmatis. This finding provides novel insights into the unique mechanism of biofilm formation regulation in mycobacteria.}, } @article {pmid30278362, year = {2019}, author = {Li, S and Li, L and Qu, Q and Kang, Y and Zhu, B and Yu, D and Huang, R}, title = {Extracellular electron transfer of Bacillus cereus biofilm and its effect on the corrosion behaviour of 316L stainless steel.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {173}, number = {}, pages = {139-147}, doi = {10.1016/j.colsurfb.2018.09.059}, pmid = {30278362}, issn = {1873-4367}, mesh = {Bacillus cereus/*chemistry/metabolism ; Bacterial Adhesion ; Biofilms/*growth & development ; Corrosion ; Electrochemical Techniques ; Electron Transport ; Electrons ; Spectroscopy, Fourier Transform Infrared ; Stainless Steel/*chemistry ; Surface Properties ; }, abstract = {Here, a heterogeneous Bacillus cereus (B. cereus) biofilm on the surface of 316 L stainless steel (SS) was observed. With electrochemical measurement and surface analysis, it was found that B. cereus biofilm could inhibit SS pitting corrosion, attributing to the blocking effect of bacterial biofilm on extracellular electron transfer (EET). Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) results also showed that B. cereus biofilm clearly impeded the EET. The proposed mechanism for the decreased corrosion rates of SS involves the interactions of extracellular polymeric substance (EPS) with SS and biofilm formation blocking electron transfer, preventing the passive layer from destroying. After biofilm formation following initial attachment of cells and EPS, electron transfer between SS and the cathodic depolarizer (oxygen) was hindered.}, } @article {pmid30278278, year = {2018}, author = {Ghaffari, S and Sarp, ASK and Lange, D and Gülsoy, M}, title = {Potassium iodide potentiated photodynamic inactivation of Enterococcus faecalis using Toluidine Blue: Comparative analysis and post-treatment biofilm formation study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {245-249}, doi = {10.1016/j.pdpdt.2018.09.019}, pmid = {30278278}, issn = {1873-1597}, mesh = {Biofilms/drug effects ; Enterococcus faecalis/*drug effects ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Potassium Iodide/*pharmacology ; Tolonium Chloride/*pharmacology ; }, abstract = {BACKGROUND: Photodynamic Inactivation (PDI) has recently gained interest as an alternative modality to fight pathogenic entities and its effect can be further enhanced by using certain inorganic salts. Here, the Potassium Iodide (KI)-mediated PDI effect on Enterococcus faecalis using Toluidine Blue Ortho (TBO) as photosensitizer (PS) has been evaluated, and subsequent Biofilm formation extent is accounted for.

METHODS: The comparative photoinactivation of TBO and TBO/KI on E.faecalis was investigated by quantifying surviving bacterial colonies after laser irradiation with 30,60, and 180 s exposure times and different PS/Potentiator concentrations. The biofilm formation capability of E.faecalis was observed by calculating Optical Density (OD595) of samples 24,48, and 72 h post-PDI treatment. Scanning Electron Microscopy (SEM) was used as a qualitative measure of bacterial biofilm growth.

RESULTS: More than 4 LOGS of photokilling was obtained for experimental groups with the highest PS/KI concentrations at 180 s exposure time. All KI-potentiated groups showed enhancement in PDI effect when compared to non-potentiated counterparts. The degree of recurring biofilm for laser-treated groups also showed to be much less than that of control group, as confirmed by both OD595 measurement and SEM imaging.}, } @article {pmid30278277, year = {2018}, author = {Pourhajibagher, M and Kazemian, H and Chiniforush, N and Hosseini, N and Pourakbari, B and Azizollahi, A and Rezaei, F and Bahador, A}, title = {Exploring different photosensitizers to optimize elimination of planktonic and biofilm forms of Enterococcus faecalis from infected root canal during antimicrobial photodynamic therapy.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {206-211}, doi = {10.1016/j.pdpdt.2018.09.014}, pmid = {30278277}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Curcumin/pharmacology ; Enterococcus faecalis/*drug effects ; Indocyanine Green/pharmacology ; Lasers, Semiconductor ; Methylene Blue/pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Plankton/*drug effects/microbiology ; Tolonium Chloride/pharmacology ; }, abstract = {BACKGROUND: Despite the high success rate of endodontic treatment, failure may occur in some cases. In this case, Enterococcus faecalis is the most common species in endodontic treatment failure and post-treatment apical periodontitis. Therefore, a new adjunctive strategy is needed for the prevention of endodontic infections due to E. faecalis. The aim of the present study was to compare the antimicrobial and anti-biofilm activities of different common photosensitizers (PSs) for use in antimicrobial photodynamic therapy (aPDT) against E. faecalis.

MATERIALS AND METHODS: E. faecalis strain ATCC 29212 was used as the tested strain and methylene blue (MB), toluidine blue O (TBO), indocyanine green (ICG), and curcumin (CUR) were used as PSs. Irradiation was carried out using diode laser and light emitting diode (LED) at wavelengths related to the above PSs. Then, antimicrobial and anti-biofilm activities were measured using the microbial viability assay and crystal violet test, respectively.

RESULTS: aPDT with using the above PSs significantly decreased the CFU/mL count of E. faecalis compared to the control group (P < 0.05). The killing percentage of E. faecalis via PS mediated aPDT was 99.6%, 98.2%, 85.1%, and 65.0% for CUR, ICG, TBO, and MB, respectively. aPDT using the above PSs significantly decreased the biofilm formation ability of E. faecalis compared to the control group (P < 0.05). The biofilm reduction percentage of the PSs was 68.4%, 62.9%, 59.0%, and 47.6% for CUR, ICG, TBO, and MB, respectively.

CONCLUSION: CUR and ICG mediated aPDT exhibited considerably more antimicrobial activity than other PSs, while TBO and MB demonstrated weaker anti-biofilm effects against E. faecalis compared to other PSs.}, } @article {pmid30276456, year = {2019}, author = {James, GA and Boegli, L and Hancock, J and Bowersock, L and Parker, A and Kinney, BM}, title = {Bacterial Adhesion and Biofilm Formation on Textured Breast Implant Shell Materials.}, journal = {Aesthetic plastic surgery}, volume = {43}, number = {2}, pages = {490-497}, pmid = {30276456}, issn = {1432-5241}, support = {111//Establishment Labs/International ; }, mesh = {*Bacterial Adhesion ; *Biofilms ; Breast Implants/*microbiology ; Prosthesis Design ; Pseudomonas aeruginosa/*physiology ; Ralstonia pickettii/*physiology ; Staphylococcus epidermidis/*physiology ; }, abstract = {BACKGROUND: Bacterial biofilms have been implicated with breast implant complications including capsular contracture and anaplastic large-cell lymphoma. The actual mechanisms for either are still under active investigation and are not clear. Due to their increased surface area, implants with textured surfaces may harbor greater biofilm loads than those with smooth surfaces.

METHODS: Biofilm formation on the outer surface material was compared using implants with various surface areas and roughness, including Natrelle[®] (Smooth), SmoothSilk[®]/SilkSurface[®] (Silk), VelvetSurface [®] (Velvet), Siltex[®], and Biocell[®]. The roughness and surface area of each material were assessed using non-contact profilometry. Bacterial attachment (2 h) and biofilm formation (24 h) were evaluated for Staphylococcus epidermidis, Pseudomonas aeruginosa, and Ralstonia pickettii over nine independent experiments using a CDC biofilm reactor and viable plate counts (VPCs) as well as confocal scanning laser microscopy. VPCs of the textured implants were compared relative to the Smooth implant.

RESULTS: Surface areas increased with roughness and were similar among the three least rough implants (Smooth, Silk, and Velvet) and among the roughest implants (Siltex and Biocell). Overall, VPC indicated there was significantly more bacterial attachment and biofilm formation on the Siltex and Biocell implants than the Silk or Velvet implants, although there were differences between species and time points. CSLM confirmed the formation of thicker biofilms on the implants with rougher surface textures.

CONCLUSION: This in vitro study confirmed that implant surfaces with rougher texture, resulting in more surface area, harbored greater biofilm loads than those with smoother surfaces.

NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .}, } @article {pmid30275239, year = {2018}, author = {Suriyanarayanan, T and Qingsong, L and Kwang, LT and Mun, LY and Truong, T and Seneviratne, CJ}, title = {Correction: Quantitative proteomics of strong and weak biofilm formers of Enterococcus faecalis reveals novel regulators of biofilm formation.}, journal = {Molecular & cellular proteomics : MCP}, volume = {17}, number = {10}, pages = {2081}, doi = {10.1074/mcp.AAC118.001077}, pmid = {30275239}, issn = {1535-9484}, } @article {pmid30274028, year = {2018}, author = {Roshani-Asl, P and Rashidi, N and Shokoohizadeh, L and Zarei, J}, title = {Relationship Among Antibiotic Resistance, Biofilm Formation and lasB Gene in Pseudomonas Aeruginosa Isolated from Burn Patients.}, journal = {Clinical laboratory}, volume = {64}, number = {9}, pages = {1477-1484}, doi = {10.7754/Clin.Lab.2018.180331}, pmid = {30274028}, issn = {1433-6510}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Burns/diagnosis/*microbiology ; Clinical Decision-Making ; Cross Infection/diagnosis/*microbiology ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Bacterial/*genetics ; Genotype ; Humans ; Length of Stay ; Metalloendopeptidases/*genetics ; Phenotype ; Polymerase Chain Reaction ; Pseudomonas Infections/diagnosis/*drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development ; Time Factors ; Treatment Outcome ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is a major cause of hospital-acquired infection due to its high antibiotic resistance and biofilm formation ability. P. aeruginosa produces elastase lasB during biofilm formation, which can influence properties of biofilm. This study was carried out to evaluate the antibiotic resistance and distribution of the lasB gene among biofilm-producing P. aeruginosa strains isolated from burn patients.

METHODS: A total of 128 clinical samples were collected from burn patients. The P. aeruginosa isolates were identified using standard bacteriological procedures. Antibiotic susceptibility test was performed by the disk diffusion method. Biofilm formation was measured by microtiter plate assay. The presence of lasB gene was detected by PCR.

RESULTS: A total of 75 samples were positive for P. aeruginosa. A high rate of resistance was seen against ceftriaxone, cefotaxime, and piperacillin/tazobactam. Biofilm formation was seen in 57.3% of the isolates and the prevalence of the lasB gene was 85.3%. Biofilm formation in isolates without lasB was lower and these isolates were more sensitive to imipenem and piperacillin/tazobactam.

CONCLUSIONS: In the present study, we did not find a statistically significant relationship among elastase gene (lasB) presence, antibiotic resistance, and biofilm formation in P. aeruginosa strains isolated from burn patients.}, } @article {pmid30273348, year = {2018}, author = {Pollini, S and Di Pilato, V and Landini, G and Di Maggio, T and Cannatelli, A and Sottotetti, S and Cariani, L and Aliberti, S and Blasi, F and Sergio, F and Rossolini, GM and Pallecchi, L}, title = {In vitro activity of N-acetylcysteine against Stenotrophomonas maltophilia and Burkholderia cepacia complex grown in planktonic phase and biofilm.}, journal = {PloS one}, volume = {13}, number = {10}, pages = {e0203941}, pmid = {30273348}, issn = {1932-6203}, mesh = {Acetylcysteine/*pharmacology ; Biofilms/*drug effects ; Burkholderia cepacia complex/drug effects/*growth & development/isolation & purification ; Cystic Fibrosis/microbiology ; Dose-Response Relationship, Drug ; Drug Resistance, Bacterial/drug effects ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Plankton/*drug effects ; Stenotrophomonas maltophilia/drug effects/*growth & development/isolation & purification ; Time Factors ; }, abstract = {Stenotrophomonas maltophilia and Burkholderia cepacia complex (Bcc) have been increasingly recognized as relevant pathogens in hospitalized, immunocompromised and cystic fibrosis (CF) patients. As a result of complex mechanisms, including biofilm formation and multidrug resistance phenotype, S. maltophilia and Bcc respiratory infections are often refractory to therapy, and have been associated with a worse outcome in CF patients. Here we demonstrate for the first time that N-acetylcysteine (NAC), a mucolytic agent with antioxidant and anti-inflammatory properties, may exhibit antimicrobial and antibiofilm activity against these pathogens. The antimicrobial and antibiofilm activity of high NAC concentrations, potentially achievable by topical administration, was tested against a collection of S. maltophilia (n = 19) and Bcc (n = 19) strains, including strains from CF patients with acquired resistance traits. Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations (MBCs) ranged from 16 to 32 mg/ml and from 32 to >32 mg/ml, respectively. Sub-MIC concentrations (i.e., 0.25 × MIC) slowed down the growth kinetics of most strains. In time-kill assays, 2-day-old biofilms were more affected than planktonic cultures, suggesting a specific antibiofilm activity of NAC against these pathogens. Indeed, a dose- and time-dependent antibiofilm activity of NAC against most of the S. maltophilia and Bcc strains tested was observed, with a sizable antibiofilm activity observed also at 0.5 and 1 × MIC NAC concentrations. Furthermore, at those concentrations, NAC was also shown to significantly inhibit biofilm formation with the great majority of tested strains.}, } @article {pmid30270674, year = {2018}, author = {Guarise, C and Barbera, C and Pavan, M and Pluda, S and Celestre, M and Galesso, D}, title = {Dopamine-functionalized sulphated hyaluronic acid as a titanium implant coating enhances biofilm prevention and promotes osseointegration.}, journal = {Biofouling}, volume = {34}, number = {7}, pages = {719-730}, doi = {10.1080/08927014.2018.1491555}, pmid = {30270674}, issn = {1029-2454}, mesh = {Alloys ; Anti-Bacterial Agents/*administration & dosage ; Biofilms ; Coated Materials, Biocompatible/*pharmacology ; Dopamine ; Hyaluronic Acid/*analogs & derivatives ; Microbial Sensitivity Tests ; Osseointegration/*drug effects ; Prostheses and Implants ; Prosthesis-Related Infections/*prevention & control ; Staphylococcal Infections/*prevention & control ; Staphylococcus aureus ; Sulfates/pharmacology ; Surface Properties ; Titanium ; }, abstract = {A series of new hyaluronan derivatives was synthesized and tested as an antibiotic release system by antibacterial and osseointegration assays. Specifically, partially sulphated hyaluronic acid (sHA) was functionalized with dopamine (DA). The DA moiety guarantees good performance as a binding agent for coating a titanium alloy surface; furthermore, the negatively charged sHA has bone regenerative effects and a high binding affinity for positively charged antibiotics. A sHA scaffold with a defined degree of sulphation (DS =2) was selected as a good compromise between a high negative charge density and poor heparin-like anticoagulant activity, while the degree of DA derivatization (17.1%mol) was chosen based on the absence of cytotoxic activity and the promotion of osteoblast proliferation. The titanium alloy coating was investigated indirectly using a fluorescent probe and directly by environmental scanning electron microscope (ESEM) analysis. Long-duration antibiotic release was demonstrated in vitro, and antibacterial efficacy against a Staphylococcus aureus culture was shown.}, } @article {pmid30269283, year = {2018}, author = {Dehghani, S and Rezaee, A and Hosseinkhani, S}, title = {Effect of alternating electrical current on denitrifying bacteria in a microbial electrochemical system: biofilm viability and ATP assessment.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {33}, pages = {33591-33598}, pmid = {30269283}, issn = {1614-7499}, mesh = {Adenosine Triphosphate/*metabolism ; Bacteria/metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Denitrification ; Electricity ; Electrochemical Techniques/*methods ; Microbial Viability ; Water Purification/*methods ; }, abstract = {The present study considers the impact of the alternating electric current on the viability and biological activity of denitrifying bacteria in a microbial electrochemical system (MES). The bio-stimulation using low-frequency low-voltage alternating current (AC) was studied in terms of the adenosine triphosphate (ATP) level of bacteria, viability, morphological characteristics, cell size, and complexity. Apoptosis assays by flow cytometry revealed that 81-95% of the cells were non-apoptotic, and cell membrane damage occurred < 18%. The applied AC could affect the bacterial metabolic activity and ATP content in the denitrifying bacteria depending on characteristics of the alternating electric current. Scanning electron microscopy (SEM) analysis of cell morphology illustrated low cell deformations under AC stimulation. The obtained results revealed that the applied alternating electrical current could increase the metabolic activity of denitrifying bacteria, leading to a better denitrification. Graphical abstract ᅟ.}, } @article {pmid30268774, year = {2018}, author = {Kuehnast, T and Cakar, F and Weinhäupl, T and Pilz, A and Selak, S and Schmidt, MA and Rüter, C and Schild, S}, title = {Comparative analyses of biofilm formation among different Cutibacterium acnes isolates.}, journal = {International journal of medical microbiology : IJMM}, volume = {308}, number = {8}, pages = {1027-1035}, doi = {10.1016/j.ijmm.2018.09.005}, pmid = {30268774}, issn = {1618-0607}, support = {P 27654/FWF_/Austrian Science Fund FWF/Austria ; }, mesh = {Acne Vulgaris/*microbiology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Deoxyribonuclease I/pharmacology ; Endopeptidase K/pharmacology ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; Microbial Viability/drug effects ; Microscopy, Fluorescence ; Organic Chemicals/pharmacology ; Propionibacteriaceae/drug effects/*growth & development/isolation & purification ; Skin/*microbiology ; }, abstract = {The Gram-positive anaerobic bacterium Cutibacterium acnes is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. Moreover, C. acnes, in addition to other skin-colonizing bacteria such as S. epidermidis and S. aureus, is an emerging pathogen of implant-associated infections. Notably, C. acnes isolates exhibit marked heterogeneity and can be divided into at least 6 phylotypes by multilocus sequence typing. It is becoming increasingly evident that biofilm formation is a relevant factor for C. acnes virulence, but information on biofilm formation by diverse C. acnes isolates is limited. In this study we performed a first comparative analysis of 58 diverse skin- or implant-isolates covering all six C. acnes phylotypes to investigate biofilm formation dynamics, biofilm morphology and attachment properties to abiotic surfaces. The results presented herein suggest that biofilm formation correlates with the phylotype, rather than the anatomical isolation site. IA1 isolates, particularly SLST sub-types A1 and A2, showed highest biofilm amounts in the microtiter plate assays, followed by isolates of the IC, IA2 and II phylotypes. Microscopic evaluation revealed well-structured three-dimensional biofilms and relatively high adhesive properties to abiotic surfaces for phylotypes IA1, IA2 and IC. Representatives of phylotype III formed biofilms with comparable biomass, but with less defined structures, whereas IB as well as II isolates showed the least complex three-dimensional morphology. Proteinase K- and DNase I-treatment reduced attachment rates of all phylotypes, therefore, indicating that extracellular DNA and proteins are critical for adhesion to abiotic surfaces. Moreover, proteins seem to be pivotal structural biofilm components as mature biofilms of all phylotypes were proteinase K-sensitive, whereas the sensitivity to DNase I-treatment varied depending on the phylotype.}, } @article {pmid30267885, year = {2018}, author = {Lee, SW and Gu, H and Kilberg, JB and Ren, D}, title = {Sensitizing bacterial cells to antibiotics by shape recovery triggered biofilm dispersion.}, journal = {Acta biomaterialia}, volume = {81}, number = {}, pages = {93-102}, pmid = {30267885}, issn = {1878-7568}, support = {R21 EY025750/EY/NEI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; *Biofouling ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*physiology ; Tobramycin/*pharmacology ; }, abstract = {Microbial biofilms are a leading cause of chronic infections in humans and persistent biofouling in industries due to extremely high-level tolerance of biofilm cells to antimicrobial agents. Eradicating mature biofilms is especially challenging because of the protection of the extracellular matrix and slow growth of biofilm cells. Recently, we reported that established biofilms can be effectively removed (e.g. 99.9% dispersion of 48 h Pseudomonas aeruginosa PAO1 biofilms) by shape memory polymer-based dynamic changes in surface topography. Here, we demonstrate that such biofilm dispersion also sensitizes biofilm cells to conventional antibiotics. For example, shape recovery in the presence of 50 µg/mL tobramycin reduced biofilm cell counts by more than 3 logs (2,479-fold) compared to the static flat control. The observed effects were attributed to the disruption of biofilm structure and increase in cellular activities as evidenced by an 11.8-fold increase in intracellular level of adenosine triphosphate (ATP), and 4.1-fold increase in expression of the rrnB gene in detached cells. These results can help guide the design of new control methods to better combat biofilm associated antibiotic-resistant infections. STATEMENT OF SIGNIFICANCE: Microbial infections are challenging due to high-level antibiotic resistance of biofilm cells. The protection of an extracellular matrix and slow growth of biofilm cells render conventional antibiotics ineffective. Thus, it is important to develop new technologies that can remove mature biofilms and sensitize biofilm cells to antibiotics. Recently, we demonstrated that dynamic change in surface topography can remove 48 h Pseudomonas aeruginosa PAO1 biofilms by 99.9%. In this study, we investigated how shape recovery triggered dispersion affect the physiology of biofilm cells and associated antibiotic susceptibility. These results are helpful for understanding biofilm dispersion and developing more effective control methods.}, } @article {pmid30265315, year = {2018}, author = {Smith, HJ and Zelaya, AJ and De León, KB and Chakraborty, R and Elias, DA and Hazen, TC and Arkin, AP and Cunningham, AB and Fields, MW}, title = {Impact of hydrologic boundaries on microbial planktonic and biofilm communities in shallow terrestrial subsurface environments.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {12}, pages = {}, pmid = {30265315}, issn = {1574-6941}, mesh = {Bacteria/classification/*growth & development ; Biofilms/*growth & development ; Fresh Water/*microbiology ; Geologic Sediments/*microbiology ; Groundwater/*microbiology ; Humans ; Hydrology ; Microbiota ; Plankton/classification/*growth & development ; }, abstract = {Subsurface environments contain a large proportion of planetary microbial biomass and harbor diverse communities responsible for mediating biogeochemical cycles important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the saturated zone, capillary fringe and vadose zones, microorganisms can reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the contribution of each phase to subsurface processes is largely unresolved. Here, we synthesize current information on the diversity and activity of shallow freshwater subsurface habitats, discuss the challenges associated with sampling planktonic and biofilm communities across spatial, temporal and geological gradients, and discuss how biofilms may be constrained within shallow terrestrial subsurface aquifers. We suggest that merging traditional activity measurements and sequencing/-omics technologies with hydrological parameters important to sediment biofilm assembly and stability will help delineate key system parameters. Ultimately, integration will enhance our understanding of shallow subsurface ecophysiology in terms of bulk-flow through porous media and distinguish the respective activities of sessile microbial communities from more transient planktonic communities to ecosystem service and maintenance.}, } @article {pmid30265307, year = {2018}, author = {Dennis, EA and Coats, MT and Griffin, S and Pang, B and Briles, DE and Crain, MJ and Swords, WE}, title = {Hyperencapsulated mucoid pneumococcal isolates from patients with cystic fibrosis have increased biofilm density and persistence in vivo.}, journal = {Pathogens and disease}, volume = {76}, number = {7}, pages = {}, pmid = {30265307}, issn = {2049-632X}, support = {P30 DK072482/DK/NIDDK NIH HHS/United States ; R01 AI118805/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Cells, Cultured ; Cystic Fibrosis/*complications ; Disease Models, Animal ; Epithelial Cells/microbiology ; Humans ; Mice ; Pneumococcal Infections/*microbiology ; Polysaccharides, Bacterial/*metabolism ; Serogroup ; Sputum/microbiology ; Streptococcus pneumoniae/classification/*isolation & purification/*physiology ; }, abstract = {Mucoid bacteria, predominately Pseudomonas aeruginosa, are commonly associated with decline in pulmonary function in children with cystic fibrosis (CF), and are thought to persist at least in part due to a greater propensity toward forming biofilms. We isolated a higher frequency of mucoid Streptococcus pneumoniae (Sp) expressing high levels of capsular polysaccharides from sputa from children with CF, compared to those without CF. We compared biofilm formation and maturation by mucoid and non-mucoid isolates of Sp collected from children with and without CF. Non-mucoid Sp serotype 19A and 19F isolates had significantly higher levels of biofilm initiation and adherence to CF epithelial cells than did serotype 3 isolates. However, strains expressing high levels of capsule had significantly greater biofilm maturation, as evidenced by increased density and thickness in static and continuous flow assays via confocal microscopy. Finally, using a serotype 3 Sp strain, we showed that highly encapsulated mucoid phase variants predominate during late adherence and better colonize CFTR-/- as compared to wild-type mice in respiratory infection studies. These findings indicate that overexpression of capsule can enhance the development of mature pneumococcal biofilms in vitro, and may contribute to pneumococcal colonization in CF lung disease.}, } @article {pmid30263875, year = {2018}, author = {Salisbury, AM and Mayer, D and Chen, R and Percival, SL}, title = {Efficacy of Concentrated Surfactant-Based Wound Dressings in Wound Repair and Biofilm Reduction.}, journal = {Advances in wound care}, volume = {7}, number = {9}, pages = {315-322}, pmid = {30263875}, issn = {2162-1918}, abstract = {Objective: This study was set up to evaluate the efficacy of a concentrated surfactant-based wound dressing (with and without silver sulfadiazine [SSD]) on wound repair, by investigating their ability to enhance human dermal fibroblast proliferation and viability. In addition, the wound dressings were evaluated for their ability to suppress biofilms in a three-dimensional (3D) in vitro wound biofilm model and modulate the inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα). Approach: Problematic biofilms are well known to affect fibroblast and keratinocyte viability. To assess wound repair and inflammatory cytokine modulation, a direct cytotoxicity assay and a 3D keratinocyte-fibroblast model were employed. Results: At 1 and 7 days posttreatment, the non-antimicrobial dressing was noncytotoxic and the antimicrobial dressing was moderately cytotoxic to adult human dermal fibroblasts cells. Within the 3D wound model, the biofilm demonstrated a decelerating effect on wound closure and a decrease in viable cells. When the non-antimicrobial- and antimicrobial-based concentrated surfactant-based wound dressing was applied to the wound model, reduced biofilm was observed. The application of wound dressings to the biofilm-infected wound also resulted in a reduction of IL-6 and TNFα. The concentrated surfactant-based wound dressing without an antimicrobial was shown to enhance cellular viability and migration. Innovation and Conclusion: We have demonstrated the ability of a surfactant-based wound dressing to minimize the deleterious effects of a wound biofilm, modulate the secretion of inflammatory cytokines, and enhance cellular proliferation in a biofilm-infected wound model. Furthermore, the non-antimicrobial-based concentrated surfactant dressings did not affect cellular viability and therefore represents a multifaceted approach to the treatment of wounds infected with biofilms.}, } @article {pmid30261443, year = {2018}, author = {Neves, BG and Stipp, RN and Bezerra, DDS and Guedes, SFF and Rodrigues, LKA}, title = {Quantitative analysis of biofilm bacteria according to different stages of early childhood caries.}, journal = {Archives of oral biology}, volume = {96}, number = {}, pages = {155-161}, doi = {10.1016/j.archoralbio.2018.09.007}, pmid = {30261443}, issn = {1879-1506}, mesh = {Bifidobacterium/*isolation & purification ; Biofilms/*classification ; Brazil ; Child, Preschool ; Dental Caries/*microbiology ; Dental Plaque/microbiology ; Female ; Humans ; Lactobacillus acidophilus/isolation & purification ; Lacticaseibacillus casei/isolation & purification ; Male ; Polymerase Chain Reaction ; Streptococcus mutans/*isolation & purification ; }, abstract = {OBJECTIVE: Monitoring selected key species related to health or disease may facilitate caries risk assessment and discovery of novel ecological preventive and therapeutic approaches. This study aimed at quantifying Actinomyces naeslundii, Bifidobacterium spp., Lactobacillus acidophilus, Lactobacillus casei group, Streptococcus gordonii, Mitis group and Streptococcus mutans by quantitative polymerase chain reaction (qPCR) in dental biofilm from Brazilian children with different stages of early childhood caries (ECC).

DESIGN: Seventy-five preschool children were clinically evaluated by ICDAS criteria and divided into groups: caries-free (CF; n = 20), enamel caries lesions (ECL; n = 17) and dentine caries lesions (DCL; n = 38). Plaque samples from all children were collected for detection and quantification of the selected bacteria.

RESULTS: L. acidophilus and L. casei group were absent in almost all plaque samples. No differences in relative proportions of A. naeslundii, Mitis group and S. gordonii were observed in any stage of caries. However, S. mutans and Bifidobacterium spp. were present at higher concentrations in the biofilm of children with DCL (p < 0.001). Multivariate analysis showed that S. mutans and Bifidobacterium spp. were strongly associated with biofilm in children with DCL.

CONCLUSION: Differences were observed in the proportion of acidogenic and aciduric bacteria with dental caries progression. The data indicate that S. mutans and Bifidobacterium spp. in dental biofilm may be involved in some progression processes for ECC.}, } @article {pmid30258571, year = {2018}, author = {Tsang, STJ and Gwynne, PJ and Gallagher, MP and Simpson, AHRW}, title = {The biofilm eradication activity of acetic acid in the management of periprosthetic joint infection.}, journal = {Bone & joint research}, volume = {7}, number = {8}, pages = {517-523}, pmid = {30258571}, issn = {2046-3758}, abstract = {OBJECTIVES: Periprosthetic joint infection following joint arthroplasty surgery is one of the most feared complications. The key to successful revision surgery for periprosthetic joint infections, regardless of treatment strategy, is a thorough deep debridement. In an attempt to limit antimicrobial and disinfectant use, there has been increasing interest in the use of acetic acid as an adjunct to debridement in the management of periprosthetic joint infections. However, its effectiveness in the eradication of established biofilms following clinically relevant treatment times has not been established. Using an in vitro biofilm model, this study aimed to establish the minimum biofilm eradication concentration (MBEC) of acetic acid following a clinically relevant treatment time.

MATERIALS AND METHODS: Using a methicillin-sensitive Staphylococcus aureus (MSSA) reference strain and the dissolvable bead assay, biofilms were challenged by 0% to 20% acetic acid (pH 4.7) for ten minutes, 20 minutes, 180 minutes, and 24 hours.

RESULTS: The MBEC of acetic acid was found to be: 15%, 11%, 3.2%, and 0.8% following a ten-minute, 20-minute, 180-minute, and 24-hour treatment, respectively.

CONCLUSION: This study found that the MBEC of acetic acid following a 10- or 20-minute treatment time exceeded its safety threshold, making these concentrations unsuitable as a topical debridement adjunct. However, a clinically acceptable concentration (5%) was still found to eliminate 96.1% of biofilm-associated MSSA following a 20-minute treatment time.Cite this article: S. T. J. Tsang, P. J. Gwynne, M. P. Gallagher, A. H. R. W. Simpson. The biofilm eradication activity of acetic acid in the management of periprosthetic joint infection. Bone Joint Res 2018;7:517-523. DOI: 10.1302/2046-3758.78.BJR-2018-0045.R1.}, } @article {pmid30258415, year = {2018}, author = {Poquet, I and Saujet, L and Canette, A and Monot, M and Mihajlovic, J and Ghigo, JM and Soutourina, O and Briandet, R and Martin-Verstraete, I and Dupuy, B}, title = {Clostridium difficile Biofilm: Remodeling Metabolism and Cell Surface to Build a Sparse and Heterogeneously Aggregated Architecture.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2084}, pmid = {30258415}, issn = {1664-302X}, abstract = {Clostridium difficile is an opportunistic entero-pathogen causing post-antibiotic and nosocomial diarrhea upon microbiota dysbiosis. Although biofilms could contribute to colonization, little is known about their development and physiology. Strain 630Δerm is able to form, in continuous-flow micro-fermentors, macro-colonies and submersed biofilms loosely adhesive to glass. According to gene expression data, in biofilm/planktonic cells, central metabolism is active and fuels fatty acid biosynthesis rather than fermentations. Consistently, succinate is consumed and butyrate production is reduced. Toxin A expression, which is coordinated to metabolism, is down-regulated, while surface proteins, like adhesins and the primary Type IV pili subunits, are over-expressed. C-di-GMP level is probably tightly controlled through the expression of both diguanylate cyclase-encoding genes, like dccA, and phosphodiesterase-encoding genes. The coordinated expression of genes controlled by c-di-GMP and encoding the putative surface adhesin CD2831 and the major Type IV pilin PilA1, suggests that c-di-GMP could be high in biofilm cells. A Bacillus subtilis SinR-like regulator, CD2214, and/or CD2215, another regulator co-encoded in the same operon as CD2214, control many genes differentially expressed in biofilm, and in particular dccA, CD2831 and pilA1 in a positive way. After growth in micro-titer plates and disruption, the biofilm is composed of robust aggregated structures where cells are embedded into a polymorphic material. The intact biofilm observed in situ displays a sparse, heterogeneous and high 3D architecture made of rods and micro-aggregates. The biofilm is denser in a mutant of both CD2214 and CD2215 genes, but it is not affected by the inactivation of neither CD2831 nor pilA1 . dccA, when over-expressed, not only increases the biofilm but also triggers its architecture to become homogeneous and highly aggregated, in a way independent of CD2831 and barely dependent of pilA1 . Cell micro-aggregation is shown to play a major role in biofilm formation and architecture. This thorough analysis of gene expression reprogramming and architecture remodeling in biofilm lays the foundation for a deeper understanding of this lifestyle and could lead to novel strategies to limit C. difficile spread.}, } @article {pmid30258041, year = {2018}, author = {Lécuyer, F and Bourassa, JS and Gélinas, M and Charron-Lamoureux, V and Burrus, V and Beauregard, PB}, title = {Biofilm Formation Drives Transfer of the Conjugative Element ICEBs1 in Bacillus subtilis.}, journal = {mSphere}, volume = {3}, number = {5}, pages = {}, pmid = {30258041}, issn = {2379-5042}, mesh = {Bacillus subtilis/genetics/*physiology ; Biofilms/*growth & development ; *Conjugation, Genetic ; DNA, Bacterial/genetics ; Drug Resistance, Bacterial ; Extracellular Matrix/genetics ; *Gene Transfer, Horizontal ; }, abstract = {Horizontal gene transfer by integrative and conjugative elements (ICEs) is a very important mechanism for spreading antibiotic resistance in various bacterial species. In environmental and clinical settings, most bacteria form biofilms as a way to protect themselves against extracellular stress. However, much remains to be known about ICE transfer in biofilms. Using ICEBs1 from Bacillus subtilis, we show that the natural conjugation efficiency of this ICE is greatly affected by the ability of the donor and recipient to form a biofilm. ICEBs1 transfer considerably increases in biofilm, even at low donor/recipient ratios. Also, while there is a clear temporal correlation between biofilm formation and ICEBs1 transfer, biofilms do not alter the level of ICEBs1 excision in donor cells. Conjugative transfer appears to be favored by the biophysical context of biofilms. Indeed, extracellular matrix production, particularly from the recipient cells, is essential for biofilms to promote ICEBs1 transfer. Our study provides basic new knowledge on the high rate of conjugative transfer of ICEs in biofilms, a widely preponderant bacterial lifestyle in the environment, which could have a major impact on our understanding of horizontal gene transfer in natural and clinical environments.IMPORTANCE Transfer of mobile genetic elements from one bacterium to another is the principal cause of the spread of antibiotic resistance. However, the dissemination of these elements in environmental contexts is poorly understood. In clinical and environmental settings, bacteria are often found living in multicellular communities encased in a matrix, a structure known as a biofilm. In this study, we examined how forming a biofilm influences the transmission of an integrative and conjugative element (ICE). Using the model Gram-positive bacterium B. subtilis, we observed that biofilm formation highly favors ICE transfer. This increase in conjugative transfer is due to the production of extracellular matrix, which creates an ideal biophysical context. Our study provides important insights into the role of the biofilm structure in driving conjugative transfer, which is of major importance since biofilm is a widely preponderant bacterial lifestyle for clinically relevant bacterial strains.}, } @article {pmid30254619, year = {2018}, author = {De, A and Jorgensen, AN and Beatty, WL and Lemos, J and Wen, ZT}, title = {Deficiency of MecA in Streptococcus mutans Causes Major Defects in Cell Envelope Biogenesis, Cell Division, and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2130}, pmid = {30254619}, issn = {1664-302X}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; R21 DE025348/DE/NIDCR NIH HHS/United States ; }, abstract = {MecA is an adaptor protein that guides the ClpC/P-mediated proteolysis. A S. mutans MecA-deficient mutant was constructed by double-crossover allelic exchange and analyzed for the effects of such a deficiency on cell biology and biofilm formation. Unlike the wild-type, UA159, the mecA mutant, TW416, formed mucoid and smooth colonies, severely clumped in broth and had a reduced growth rate. Transmission electron microscopy analysis revealed that TW416 grows primarily in chains of giant "swollen" cells with multiple asymmetric septa, unlike the coccoid form of UA159. As compared to UA159, biofilm formation by TW416 was significantly reduced regardless of the carbohydrate sources used for growth (P < 0.001). Western blot analysis of TW416 whole cell lysates showed a reduced expression of the glucosyltransferase GtfC and GtfB, as well as the P1 and WapA adhesins providing an explanation for the defective biofilm formation of TW416. When analyzed by a colorimetric assay, the cell wall phosphate of the mutant murein sacculi was almost 20-fold lower than the parent strain (P < 0.001). Interestingly, however, when analyzed using immunoblotting of the murein sacculi preps with UA159 whole cell antiserum as a probe, TW416 was shown to possess significantly higher signal intensity as compared to the wild-type. There is also evidence that MecA in S. mutans is more than an adaptor protein, although how it modulates the bacterial pathophysiology, including cell envelope biogenesis, cell division, and biofilm formation awaits further investigation.}, } @article {pmid30254440, year = {2018}, author = {Zhang, X and Geng, H and Gong, L and Zhang, Q and Li, H and Zhang, X and Wang, Y and Gao, P}, title = {Modification of the surface of titanium with multifunctional chimeric peptides to prevent biofilm formation via inhibition of initial colonizers.}, journal = {International journal of nanomedicine}, volume = {13}, number = {}, pages = {5361-5375}, pmid = {30254440}, issn = {1178-2013}, mesh = {Adsorption ; Amino Acid Sequence ; Animals ; Anti-Infective Agents/pharmacology ; Apoptosis/drug effects ; Bacteria/*drug effects/*growth & development ; Biofilms/*drug effects ; Cell Line ; Circular Dichroism ; Colony Count, Microbial ; Humans ; Mice ; Microbial Sensitivity Tests ; Oligopeptides/chemistry/*pharmacology ; Surface Properties ; Titanium/chemistry/*pharmacology ; beta-Defensins/metabolism ; }, abstract = {BACKGROUND: Prevention of bacterial colonization remains a major challenge in the field of oral implant devices. Chimeric peptides with binding, antimicrobial, and osteogenesis motifs may provide a promising alternative for the inhibition of biofilm formation on titanium (Ti) surfaces.

METHODS: In this study, chimeric peptides were designed by connecting an antimicrobial sequence from human β-defensin-3 with a Ti-binding sequence and arginine-glycine-aspartic acid using a glycine-glycine-glycine linker. Binding to the Ti substrate and antimicrobial properties against streptococci were evaluated. Significant improvement in reduction of bacterial colonization onto the Ti surface was observed, with or without the presence of saliva or serum. The MC3T3-E1 cells grew well on the modified Ti surfaces compared with the control group.

RESULTS: The data showed that the three peptide functional motifs maintained their respective functions, and that the antibiofilm mechanism of the chimeric peptide was via suppression of sspA and sspB gene expression.

CONCLUSION: These results indicated that the endogenous peptide fragments engineered on the Ti surface could provide an environmentally friendly approach for improving the biocompatibility of oral implants.}, } @article {pmid30254118, year = {2018}, author = {Reichhardt, C and Wong, C and Passos da Silva, D and Wozniak, DJ and Parsek, MR}, title = {CdrA Interactions within the Pseudomonas aeruginosa Biofilm Matrix Safeguard It from Proteolysis and Promote Cellular Packing.}, journal = {mBio}, volume = {9}, number = {5}, pages = {}, pmid = {30254118}, issn = {2150-7511}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; R01 AI134895/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Bacterial Proteins/metabolism ; Biofilms/drug effects/*growth & development ; Extracellular Polymeric Substance Matrix/metabolism ; *Gene Expression Regulation, Bacterial ; Metalloendopeptidases/metabolism ; Peptide Hydrolases ; Polysaccharides, Bacterial/metabolism ; Proteolysis ; Pseudomonas aeruginosa/*enzymology/genetics ; }, abstract = {Biofilms are robust multicellular aggregates of bacteria that are encased in an extracellular matrix. Different bacterial species have been shown to use a range of biopolymers to build their matrices. Pseudomonas aeruginosa is a model organism for the laboratory study of biofilms, and past work has suggested that exopolysaccharides are a required matrix component. However, we found that expression of the matrix protein CdrA, in the absence of biofilm exopolysaccharides, allowed biofilm formation through the production of a CdrA-rich proteinaceous matrix. This represents a novel function for CdrA. Similar observations have been made for other species such as Escherichia coli and Staphylococcus aureus, which can utilize protein-dominant biofilm matrices. However, we found that these CdrA-containing matrices were susceptible to both exogenous and self-produced proteases. We previously reported that CdrA directly binds the biofilm matrix exopolysaccharide Psl. Now we have found that when CdrA bound to Psl, it was protected from proteolysis. Together, these results support the idea of the importance of multibiomolecular components in matrix stability and led us to propose a model in which CdrA-CdrA interactions can enhance cell-cell packing in an aggregate that is resistant to physical shear, while Psl-CdrA interactions enhance aggregate integrity in the presence of self-produced and exogenous proteases.IMPORTANCEPseudomonas aeruginosa forms multicellular aggregates or biofilms using both exopolysaccharides and the CdrA matrix adhesin. We showed for the first time that P. aeruginosa can use CdrA to build biofilms that do not require known matrix exopolysaccharides. It is appreciated that biofilm growth is protective against environmental assaults. However, little is known about how the interactions between individual matrix components aid in this protection. We found that interactions between CdrA and the exopolysaccharide Psl fortify the matrix by preventing CdrA proteolysis. When both components-CdrA and Psl-are part of the matrix, robust aggregates form that are tightly packed and protease resistant. These findings provide insight into how biofilms persist in protease-rich host environments.}, } @article {pmid30252827, year = {2018}, author = {Danino, MA and Paek, LS and Elkhatib, A and Obeid, F and Boumerhi, J}, title = {Reply: Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.}, journal = {Plastic and reconstructive surgery}, volume = {142}, number = {4}, pages = {589e-590e}, doi = {10.1097/PRS.0000000000004745}, pmid = {30252827}, issn = {1529-4242}, mesh = {Bacteria ; Biofilms ; *Breast Implantation ; *Breast Implants ; }, } @article {pmid30252650, year = {2018}, author = {Cheng, X and Xu, W and Wang, N and Mu, Y and Zhu, J and Luo, J}, title = {Adsorption of Cu[2+] and mechanism by natural biofilm.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {78}, number = {3-4}, pages = {721-731}, doi = {10.2166/wst.2018.308}, pmid = {30252650}, issn = {0273-1223}, mesh = {Adsorption ; *Biofilms ; Microscopy, Electron, Scanning ; Molecular Weight ; *Spectroscopy, Fourier Transform Infrared ; }, abstract = {The biofilm culturing device fixed on the slides was vertically placed in the commonly called small Li Lake of Jiangnan University. The adsorption experiment of Cu[2+] was carried out by mature biofilm. Besides, scanning electron microscope (SEM), polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy spectrum (SEM-EDX) were used to analysis the effect of Cu[2+] on the morphological structure of biofilm. The result indicated that when the initial concentration of Cu[2+] was 5 mg·L[-1], the absorption capacity of Cu[2+] by unit mass biofilm is the maximum. More extracellular polymeric substances (EPS) were released by biofilm due to the stimulation of Cu[2+]. EPS was beneficial to the adsorption of Cu[2+] by biofilm. After the adsorption of Cu[2+], the bacterial diversity index decreased, while there were no significant differences in microbial communities on biofilm. Moreover, the main groups combining Cu[2+] were the hydroxyl groups and amide groups in S-EPS and B-EPS. Ion exchange is a mechanism of the adsorption of Cu[2+] by EPS.}, } @article {pmid30252590, year = {2019}, author = {Ovesen, S and Durack, J and Kirk, KF and Nielsen, HL and Nielsen, H and Lynch, SV}, title = {Motility and biofilm formation of the emerging gastrointestinal pathogen Campylobacter concisus differs under microaerophilic and anaerobic environments.}, journal = {Gut microbes}, volume = {10}, number = {1}, pages = {34-44}, pmid = {30252590}, issn = {1949-0984}, mesh = {Adolescent ; Adult ; Aerobiosis ; Aged ; Anaerobiosis ; Biofilms/*growth & development ; Campylobacter/growth & development/metabolism/*physiology ; Campylobacter Infections/*microbiology ; Female ; Gastroenteritis/*microbiology ; Humans ; Inflammatory Bowel Diseases/microbiology ; Male ; Middle Aged ; Oxygen/*metabolism ; Young Adult ; }, abstract = {Campylobacter concisus has been isolated from patients with gastroenteritis and inflammatory bowel disease (IBD), as well as healthy subjects. While strain differences may plausibly explain virulence differentials, an alternative hypothesis posits that the pathogenic potential of this species may depend on altered ecosystem conditions in the inflamed gut. One potential difference is oxygen availability, which is frequently increased under conditions of inflammation and is known to regulate bacterial virulence. Hence, we hypothesized that oxygen influences C. concisus physiology. We therefore characterized the effect of microaerophilic or anaerobic environments on C. concisus motility and biofilm formation, two important determinants of host colonization and dissemination. C. concisus isolates (n = 46) sourced from saliva, gut mucosal biopsies and feces of patients with IBD (n = 23), gastroenteritis (n = 8) and healthy subjects (n = 13), were used for this study. Capacity to form biofilms was determined using crystal violet assay, while assessment of dispersion through soft agar permitted motility to be assessed. No association existed between GI disease and either motility or biofilm forming capacity. Oral isolates exhibited significantly greater capacity for biofilm formation compared to fecal isolates (p<0.03), and showed a strong negative correlation between motility and biofilm formation (r = -0.7; p = 0.01). Motility significantly increased when strains were cultured under microaerophilic compared to anaerobic conditions (p<0.001). Increased biofilm formation under microaerophillic conditions was also observed for a subset of isolates. Hence, differences in oxygen availability appear to influence key physiological aspects of the opportunistic gastrointestinal pathogen C. concisus.}, } @article {pmid30249749, year = {2018}, author = {Pang, B and Armbruster, CE and Foster, G and Learman, BS and Gandhi, U and Swords, WE}, title = {Autoinducer 2 (AI-2) Production by Nontypeable Haemophilus influenzae 86-028NP Promotes Expression of a Predicted Glycosyltransferase That Is a Determinant of Biofilm Maturation, Prevention of Dispersal, and Persistence In Vivo.}, journal = {Infection and immunity}, volume = {86}, number = {12}, pages = {}, pmid = {30249749}, issn = {1098-5522}, support = {R01 DC007444/DC/NIDCD NIH HHS/United States ; R01 DC010051/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/genetics ; Carrier Proteins/genetics/*metabolism ; Chinchilla/microbiology ; Gene Expression Profiling ; Glycosyltransferases/genetics/*metabolism ; Haemophilus Infections/microbiology ; Haemophilus influenzae/genetics/*metabolism ; Homoserine/*analogs & derivatives/genetics/metabolism ; Intracellular Signaling Peptides and Proteins ; Lactones/*metabolism ; Mutation ; Otitis Media/microbiology ; Real-Time Polymerase Chain Reaction ; Transcription, Genetic ; Xylose/metabolism ; }, abstract = {Nontypeable Haemophilus influenzae (NTHi) is an extremely common human pathobiont that persists on the airway mucosal surface within biofilm communities, and our previous work has shown that NTHi biofilm maturation is coordinated by the production and uptake of autoinducer 2 (AI-2) quorum signals. To directly test roles for AI-2 in maturation and maintenance of NTHi biofilms, we generated an NTHi 86-028NP mutant in which luxS transcription was under the control of the xylA promoter (NTHi 86-028NP luxS xylA::luxS), rendering AI-2 production inducible by xylose. Comparison of biofilms under inducing and noninducing conditions revealed a biofilm defect in the absence of xylose, whereas biofilm maturation increased following xylose induction. The removal of xylose resulted in the interruption of luxS expression and biofilm dispersal. Measurement of luxS transcript levels by real-time reverse transcription-PCR (RT-PCR) showed that luxS expression peaked as biofilms matured and waned before dispersal. Transcript profiling revealed significant changes following the induction of luxS, including increased transcript levels for a predicted family 8 glycosyltransferase (NTHI1750; designated gstA); this result was confirmed by real-time RT-PCR. An isogenic NTHi 86-028NP gstA mutant had a biofilm defect, including decreased levels of sialylated matrix and significantly altered biofilm structure. In experimental chinchilla infections, we observed a significant decrease in the number of bacteria in the biofilm population (but not in effusions) for NTHi 86-028NP gstA compared to the parental strain. Therefore, we conclude that AI-2 promotes NTHi biofilm maturation and the maintenance of biofilm integrity, due at least in part to the expression of a probable glycosyltransferase that is potentially involved in the synthesis of the biofilm matrix.}, } @article {pmid30249747, year = {2018}, author = {Heim, CE and West, SC and Ali, H and Kielian, T}, title = {Heterogeneity of Ly6G[+] Ly6C[+] Myeloid-Derived Suppressor Cell Infiltrates during Staphylococcus aureus Biofilm Infection.}, journal = {Infection and immunity}, volume = {86}, number = {12}, pages = {}, pmid = {30249747}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; P20 GM103427/GM/NIGMS NIH HHS/United States ; P30 CA036727/CA/NCI NIH HHS/United States ; P30 GM110768/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Antigens, Ly/*genetics/immunology ; *Biofilms ; CD11b Antigen/genetics ; Cell Proliferation ; Disease Models, Animal ; Female ; Gene Expression Profiling ; High-Throughput Nucleotide Sequencing ; Lymphocyte Activation ; Male ; Mice ; Mice, Inbred C57BL ; Monocytes/immunology ; Myeloid-Derived Suppressor Cells/*immunology ; Neutrophils/*immunology ; Staphylococcal Infections/*immunology ; Staphylococcus aureus ; }, abstract = {Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature monocytes and granulocytes. While neutrophils (polymorphonuclear leukocytes [PMNs]) are classically identified as highly differentiated cells specialized for antimicrobial defense, our laboratory has reported minor contributions of PMNs to the immune response during Staphylococcusaureus biofilm infection. However, these two cell types can be difficult to differentiate because of shared surface marker expression. Here we describe a more refined approach to distinguish MDSCs from PMNs utilizing the integrin receptor CD11b combined with conventional Ly6G and Ly6C expression. This approach separated the Ly6G[+] Ly6C[+] population that we previously identified in a mouse model of S. aureus orthopedic implant infection into two subsets, namely, CD11b[high] Ly6G[+] Ly6C[+] MDSCs and CD11b[low] Ly6G[+] Ly6C[+] PMNs, which was confirmed by characteristic nuclear morphology using cytospins. CD11b[high] Ly6G[+] Ly6C[+] MDSCs suppressed T cell proliferation throughout the 28-day infection period, whereas CD11b[low] Ly6G[+] Ly6C[+] PMNs had no effect early (day 3 postinfection), although this population acquired suppressive activity at later stages of biofilm development. To further highlight the distinctions between biofilm-associated MDSCs and PMNs versus monocytes, transcriptional profiles were compared by transcriptome sequencing (RNA-Seq). A total of 6,466 genes were significantly differentially expressed in MDSCs versus monocytes, whereas only 297 genes were significantly different between MDSCs and PMNs. A number of genes implicated in cell cycle regulation were identified, and in vivo ethynyldeoxyuridine (EdU) labeling revealed that approximately 50% of MDSCs proliferated locally at the site of S. aureus biofilm infection. Based on their similar transcriptomic profiles to those of PMNs, biofilm-associated MDSCs are of a granulocytic lineage and can be classified as granulocytic MDSCs (G-MDSCs).}, } @article {pmid30249706, year = {2018}, author = {Afonina, I and Lim, XN and Tan, R and Kline, KA}, title = {Planktonic Interference and Biofilm Alliance between Aggregation Substance and Endocarditis- and Biofilm-Associated Pili in Enterococcus faecalis.}, journal = {Journal of bacteriology}, volume = {200}, number = {24}, pages = {}, pmid = {30249706}, issn = {1098-5530}, mesh = {Adhesins, Bacterial/*genetics/*metabolism ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Bacteriological Techniques ; Biofilms/growth & development ; Endocarditis, Bacterial/microbiology ; Enterococcus faecalis/growth & development/metabolism/*physiology ; Gene Transfer, Horizontal ; Humans ; Pheromones/pharmacology ; }, abstract = {Like many bacteria, Enterococcus faecalis encodes a number of adhesins involved in colonization or infection of different niches. Two well-studied E. faecalis adhesins, aggregation substance (AS) and endocarditis- and biofilm-associated pili (Ebp), both contribute to biofilm formation on abiotic surfaces and in endocarditis, suggesting that they may be expressed at the same time. Because different regulatory pathways have been reported for AS and Ebp, here, we examined if they are coexpressed on the same cells and what is the functional impact of coexpression on individual cells and within a population. We found that while Ebp are only expressed on a subset of cells, when Ebp and AS are expressed on the same cells, pili interfere with AS-mediated clumping and impede AS-mediated conjugative plasmid transfer during planktonic growth. However, when the population density increases, horizontal gene transfer rates normalize and are no longer affected by pilus expression. Instead, at higher cell densities during biofilm formation, Ebp and AS differentially contribute to biofilm development and structure, synergizing to promote maximal biofilm formation.IMPORTANCE Most bacteria express multiple adhesins that contribute to surface attachment and colonization. However, the network and relationships between the various adhesins of a single bacterial species are less well understood. Here, we examined two well-characterized adhesins in Enterococcus faecalis, aggregation substance and endocarditis- and biofilm-associated pili, and found that they exhibit distinct functional contributions depending on the growth stage of the bacterial community. Pili interfere with aggregation substance-mediated clumping and plasmid transfer under planktonic conditions, whereas the two adhesins structurally complement one another during biofilm development. This study advances our understanding of how E. faecalis, a ubiquitous member of the human gut microbiome and an opportunistic pathogen, uses multiple surface structures to evolve and thrive.}, } @article {pmid30248650, year = {2018}, author = {Li, J and Ye, W and Wei, D and Ngo, HH and Guo, W and Qiao, Y and Xu, W and Du, B and Wei, Q}, title = {System performance and microbial community succession in a partial nitrification biofilm reactor in response to salinity stress.}, journal = {Bioresource technology}, volume = {270}, number = {}, pages = {512-518}, doi = {10.1016/j.biortech.2018.09.068}, pmid = {30248650}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Microbiota ; Nitrification ; Salinity ; *Salt Stress ; }, abstract = {The system performance and microbial community succession in a partial nitrification biofilm reactor in response to salinity stress was conducted. It was found that the NH4[+]-N removal efficiency decreased from 98.4% to 42.0% after salinity stress increased to 20 g/L. Specific oxygen uptake rates suggested that AOB activity was more sensitive to the stress of salinity than that of NOB. Protein and polysaccharides contents showed an increasing tendency in both LB-EPS and TB-EPS after the salinity exposure. Moreover, EEM results indicated that protein-like substances were the main component in LB-EPS and TB-EPS as self-protection in response to salinity stress. Additionally, humic acid-like substances were identified as the main component in the effluent organic matter (EfOM) of partial nitrification biofilm, whereas fulvic acid-like substances were detected at 20 g/L salinity stress. Microbial community analysis found that Nitrosomonas as representative species of AOB were significantly inhibited under high salinity condition.}, } @article {pmid30247876, year = {2018}, author = {Hagras, M and Abutaleb, NS and Ali, AO and Abdel-Aleem, JA and Elsebaei, MM and Seleem, MN and Mayhoub, AS}, title = {Naphthylthiazoles: Targeting Multidrug-Resistant and Intracellular Staphylococcus aureus with Biofilm Disruption Activity.}, journal = {ACS infectious diseases}, volume = {4}, number = {12}, pages = {1679-1691}, doi = {10.1021/acsinfecdis.8b00172}, pmid = {30247876}, issn = {2373-8227}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Drug Design ; *Drug Resistance, Multiple, Bacterial ; Enterococcus/drug effects/growth & development ; Humans ; Microbial Sensitivity Tests ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects/genetics/physiology ; Structure-Activity Relationship ; Thiazoles/*chemistry/*pharmacology ; }, abstract = {Thirty-two new naphthylthiazole derivatives were synthesized with the aim of exploring their antimicrobial effect on multidrug-resistant Gram-positive bacteria. Compounds 25 and 32, with ethylenediamine and methylguanidine side chains, represent the most promising derivatives, as their antibacterial spectrum includes activity against multidrug-resistant staphylococcal and enterococcal strains. Moreover, the new derivatives are highly advantageous over the existing frontline therapeutics for the treatment of multidrug-resistant Gram-positive bacteria. In this vein, compound 25 possesses three attributes: no bacterial resistance was developed against it even after 15 passages, it was very efficient in targeting intracellular pathogens, and it exhibited a concentration-dependent ability to disrupt the preformed bacterial biofilm.}, } @article {pmid30246765, year = {2018}, author = {Pournajaf, A and Razavi, S and Irajian, G and Ardebili, A and Erfani, Y and Solgi, S and Yaghoubi, S and Rasaeian, A and Yahyapour, Y and Kafshgari, R and Shoja, S and Rajabnia, R}, title = {Integron types, antimicrobial resistance genes, virulence gene profile, alginate production and biofilm formation in Iranian cystic fibrosis Pseudomonas aeruginosa isolates.}, journal = {Le infezioni in medicina}, volume = {26}, number = {3}, pages = {226-236}, pmid = {30246765}, issn = {2532-8689}, mesh = {Adolescent ; Alginates/*metabolism ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Child ; Cystic Fibrosis/complications/*microbiology ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Bacterial ; Female ; Genes, Bacterial ; Geography, Medical ; Humans ; Integrons/*genetics ; Iran/epidemiology ; Male ; Pseudomonas Infections/epidemiology/*microbiology ; Pseudomonas aeruginosa/drug effects/genetics/*isolation & purification/metabolism ; Virulence ; Virulence Factors/genetics ; }, abstract = {Cystic fibrosis (CF) patients commonly suffer from continuous and recurrent lung infections caused by Pseudomonas aeruginosa, the dominant pathogen in CF airways. This study aimed to determine the integron types, gene cassettes, virulence determinants, β-lactam resistance genes, biofilm formation and alginate production in P. aeruginosa isolated from Iranian CF patients. A total of 143 P. aeruginosa isolates were obtained from CF patients. Susceptibility of isolates to different antimicrobials was evaluated by disc diffusion method. ESBL, MBL and KPC production was assessed. Congo red agar and tissue culture plates were used for evaluation of biofilm formation. Alginate production was determined using the Carbazole assay. Integrase genes, resistance determinants (ESBLs, MBLs and KPC) and genes encoding virulence factors were evaluated by PCR. All isolates were susceptible to colistin, piperacillin-tazobactam and ticarcillin; 8.4% of isolates were considered as MDR phenotype. Out of 6.3% IPM-resistant isolates, prevalence of virulence genes was as follows: lasB (100%) and plcB (100%), plcH (96.5%). Biofilm formation and alginate production ability were found in 54.5% of isolates. The prevalence of the alginate-encoding genes was 92.3%, 86.7% and 67.1% for algD, algU and algL genes, respectively. PpyR, pslA and pelA genes were detected in 98.6%, 89.5% and 57.3% of the isolates, respectively. The high prevalence of colonization in CF lungs may increase the pathogenicity of P. aeruginosa due to their adhesion and protective properties caused by biofilm- and alginate-production. LasB, plcB, plcH, exoS, toxA, algD, ppyR and pslA genes were predominant in CF P. aeruginosa strains.}, } @article {pmid30245590, year = {2018}, author = {Yang, Y and Shao, Z and Du, J and He, Q and Chai, H}, title = {Enhancement of Organic Matter Removal in an Integrated Biofilm-Membrane Bioreactor Treating High-Salinity Wastewater.}, journal = {Archaea (Vancouver, B.C.)}, volume = {2018}, number = {}, pages = {2148286}, pmid = {30245590}, issn = {1472-3654}, mesh = {Aerobiosis ; Ammonium Compounds/analysis ; Anaerobiosis ; Ascomycota ; Bacteria/metabolism/ultrastructure ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; *Membranes ; Metagenome ; Microscopy, Electron, Scanning ; Nitrogen/analysis ; Organic Chemicals/*metabolism ; Phosphorus/analysis ; *Salinity ; *Wastewater ; Water Purification/*methods ; }, abstract = {High salinity can strongly inhibit microbial activity and decrease the sedimentation ability of activated sludge. The combination of biofilm and membrane bioreactor is a practical approach towards effective removal of pollutants and low fouling rate. An integrated biofilm-membrane bioreactor (BMBR) treating mustard tuber wastewater was investigated. An average COD removal efficiency of 94.81% and ammonium removal efficiency of 96.84% were achieved at an organic load of 0.5 kg COD/(m[3]·d). However, the reactor showed a relatively low efficiency in total nitrogen and soluble phosphorus removal due to the lack of anaerobic environment. The increase of influent organic load resulted in a performance degradation because a balance between the degradation ability and pollution has been reached. Images of scanning electron microscopy revealed that halophilic bacteria were the dominant microbe in the system that leads to a loose sludge structure and declined settling properties. It was found that membrane fouling was the consequence of the interaction of microbial activities and NaCl crystallization.}, } @article {pmid30245456, year = {2018}, author = {Cai, P and Liu, X and Ji, D and Yang, S and Walker, SL and Wu, Y and Gao, C and Huang, Q}, title = {Impact of soil clay minerals on growth, biofilm formation, and virulence gene expression of Escherichia coli O157:H7.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {243}, number = {Pt B}, pages = {953-960}, doi = {10.1016/j.envpol.2018.09.032}, pmid = {30245456}, issn = {1873-6424}, mesh = {Bentonite ; Biofilms/*growth & development ; Clay/*chemistry ; Escherichia coli O157/*genetics ; Iron Compounds ; Kaolin ; Minerals ; Soil ; Virulence ; }, abstract = {Soil, composed mainly of minerals, plays a central role in the circulation of microbial pathogens in the environment. Herein, the growth, biofilm formation, and virulence gene expression of the pathogenic bacteria Escherichia coli O157:H7 were monitored following exposure to montmorillonite, kaolinite, and goethite, three common soil minerals in the clay size fraction. E. coli O157:H7 growth was notably promoted (P < 0.05), while biofilm formation was inhibited in the presence of montmorillonite (P < 0.05), which is attributed to the suppression of colanic acid (CA) production and an increase in bacterial motility. Kaolinite not only promoted bacterial growth (P < 0.05), but also contributed to biofilm formation upon stimulating CA production. Upon exposure to goethite, notably slower bacterial growth and higher biomass of biofilm were observed as compared to the control (P < 0.05). Goethite stimulated the synthesis of CA to encase cells in a protective biofilm in response to the tight association between bacteria and goethite, which could cause bacterial death. Additionally, the transcription of virulence factors (stxA-1 and stxA-2) was significantly decreased in goethite or kaolinite system (P < 0.05). These findings indicate that minerals play important roles in the physiological state of bacteria and ultimately govern the fate of this pathogen in soils.}, } @article {pmid30245399, year = {2018}, author = {Li, YB and Liu, J and Huang, ZX and Yu, JH and Xu, XF and Sun, PH and Lin, J and Chen, WM}, title = {Design, synthesis and biological evaluation of 2-substituted 3-hydroxy-6-methyl-4H-pyran-4-one derivatives as Pseudomonas aeruginosa biofilm inhibitors.}, journal = {European journal of medicinal chemistry}, volume = {158}, number = {}, pages = {753-766}, doi = {10.1016/j.ejmech.2018.09.041}, pmid = {30245399}, issn = {1768-3254}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/*drug effects ; Humans ; Methylation ; Mice ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/*drug effects/physiology ; Pyrans/chemical synthesis/*chemistry/*pharmacology ; Quorum Sensing/drug effects ; RAW 264.7 Cells ; }, abstract = {Drug-resistant bacteria associated with biofilm formation are rapidly on the rise, requiring novel therapeutic options to combat biofilm induced drug-resistance. In this study, a class of 3-hydroxy-2-(phenylhydroxy-methyl)-6-methyl-4H-pyran-4-one derivatives (1a-1e) were found by screening of an in-house compound library to be potential Pseudomonas aeruginosa biofilm inhibitors. Thirty one novel 2-substituted 3-hydroxy-6-methyl-4H-pyran-4-one derivatives were synthesized and assayed for their biofilm inhibitory activity. A promising biofilm inhibitor 6a was identified, and showed an obvious biofilm inhibitory effect even at a concentration of 2.5 μM. Further mechanism studies revealed that 6a only shows inhibitory effects on the expression of pqsA-gfp in a fluorescent reporter strain, and the production of a PQS- regulated virulence factor, pyocyanin. This indicates that this type of compound exercises its anti-biofilm activity specifically through the PQS pathway. Novel chemical biofilm inhibitors are described here and guard against biofilm formation associated with Pseudomonas aeruginosa infections.}, } @article {pmid30245289, year = {2019}, author = {Barilli, E and Vismarra, A and Villa, Z and Bonilauri, P and Bacci, C}, title = {ESβL E. coli isolated in pig's chain: Genetic analysis associated to the phenotype and biofilm synthesis evaluation.}, journal = {International journal of food microbiology}, volume = {289}, number = {}, pages = {162-167}, doi = {10.1016/j.ijfoodmicro.2018.09.012}, pmid = {30245289}, issn = {1879-3460}, mesh = {Animals ; *Biofilms ; Escherichia coli/classification/*genetics/growth & development/isolation & purification ; Food Handling ; *Food Microbiology ; Genes, Bacterial/genetics ; Humans ; Phenotype ; Red Meat/microbiology ; Swine/*microbiology ; beta-Lactamases/genetics ; }, abstract = {Resistance to new generation cephalosporins is an important public health problem globally, in terms of economic and social costs, morbidity and mortality. Βeta-lactamase enzymes are mainly responsible for the antibiotic resistance of Gram negative bacteria and extended-spectrum-β-lactamases (ESβLs) are one of the major determinants of resistance against oxymino-cephalosporins in Enterobacteriaceae. Food-producing animals represent one of the sources of antibiotic resistant bacteria, including pigs. Here we analysed the presence of E. coli resistant to III generation cephalosporins isolated from different matrices collected from intensively bred pigs. A total of 498 E. coli were isolated from faeces and carcasses of pigs at slaughterhouse as well as from pork meat and sausages. Among these, 73 were phenotypically confirmed to be ESβL producers. Genetic analysis revealed that all except two harboured at least one of the three selected genes: blaCTX-M, blaTEM, and blaSHV. Furthermore, six of the E. coli ESβL isolated from faeces and carcasses swabs, were also able to produce biofilm, highlighting the virulence potential of these strains. The presence of Multi-Drug-Resistance patterns (MDR) recorded by the 73 ESβL E. coli was significant (60% of the strains were resistant to more than six antibiotics in MIC test). Results from the present study show that the transmission of resistant bacteria is possible along the food chain, including production of pork, one the most highly consumed meats around the world. Transmission is possible through the ingestion of raw meat products, and following cross-contamination between raw and cooked foods during preparation. The potential risk for human health demonstrated here, associated with the consumption of pork contaminated with bacterial strains characterized by multidrug resistance patterns, and the ability to produce ESβL and biofilm, is cause for concern. It is imperative to study future control strategies to avoid or limit as much as possible the transmission of these highly pathogenic strains through food consumption and/or contact with the environment.}, } @article {pmid30242260, year = {2018}, author = {Anderson, AC and Rothballer, M and Altenburger, MJ and Woelber, JP and Karygianni, L and Lagkouvardos, I and Hellwig, E and Al-Ahmad, A}, title = {In-vivo shift of the microbiota in oral biofilm in response to frequent sucrose consumption.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {14202}, pmid = {30242260}, issn = {2045-2322}, support = {AL-1179/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/International ; AL-1179/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/International ; }, mesh = {Adult ; Biofilms/*drug effects/*growth & development ; Dental Caries/microbiology ; Dental Enamel/microbiology ; Dental Plaque/microbiology ; Female ; Humans ; Male ; Microbiota/*drug effects ; Middle Aged ; Mouth/*microbiology ; Streptococcus/drug effects ; Sucrose/*adverse effects ; Young Adult ; }, abstract = {Caries is associated with shifts of microbiota in dental biofilms and primarily driven by frequent sucrose consumption. Data on environmentally induced in vivo microbiota shifts are scarce therefore we investigated the influence of frequent sucrose consumption on the oral biofilm. Splint systems containing enamel slabs were worn for 3 × 7 days with 7-day intervals to obtain oral biofilm samples. After a three-month dietary change of sucking 10 g of sucrose per day in addition to the regular diet, biofilm was obtained again at the end of the second phase. The microbiota was analysed using Illumina MiSeq amplicon sequencing (v1-v2 region). In addition, roughness of the enamel surface was measured with laser scanning microscopy. The sucrose phase resulted in significant differences in beta-diversity and significantly decreased species richness. It was marked by a significant increase in abundance of streptococci, specifically Streptococcus gordonii, Streptococcus parasanguinis and Streptococcus sanguinis. Enamel surface roughness began to increase, reflecting initial impairment of dental enamel surface. The results showed that frequent sucrose consumption provoked compositional changes in the microbiota, leading to an increase of non-mutans streptococci, hence supporting the extended ecological plaque hypothesis and emphasizing the synergy of multiple bacterial species in the development of caries.}, } @article {pmid30241381, year = {2018}, author = {Souza, LBFC and Silva-Rocha, WP and Ferreira, MRA and Soares, LAL and Svidzinski, TIE and Milan, EP and Pires, RH and Fusco Almeida, AM and Mendes-Giannini, MJS and Maranhão Chaves, G}, title = {Influence of Eugenia uniflora Extract on Adhesion to Human Buccal Epithelial Cells, Biofilm Formation, and Cell Surface Hydrophobicity of Candida spp. from the Oral Cavity of Kidney Transplant Recipients.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {10}, pages = {}, pmid = {30241381}, issn = {1420-3049}, support = {PROCAD-NF-2008//CAPES/ ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/pathogenicity ; Cell Adhesion/drug effects ; Cell Extracts/*chemistry/pharmacology ; Epithelial Cells/chemistry/drug effects ; Eugenia/*chemistry ; Humans ; Hydrophobic and Hydrophilic Interactions/drug effects ; Kidney Transplantation/adverse effects ; Mouth/drug effects ; Mouth Mucosa/chemistry ; Surface Properties/drug effects ; Virulence Factors/chemistry ; }, abstract = {This study evaluated the influence of the extract of Eugenia uniflora in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of Candida spp. isolated from the oral cavity of kidney transplant patients. To evaluate virulence attributes in vitro, nine yeasts were grown in the presence and absence of 1000 μg/mL of the extract. Adhesion was quantified using the number of Candida cells adhered to 150 HBEC determined by optical microscope. Biofilm formation was evaluated using two methodologies: XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and crystal violet assay, and further analyzed by electronic scan microscopy. CSH was quantified with the microbial adhesion to hydrocarbons test. We could detect that the extract of E. uniflora was able to reduce adhesion to HBEC and CSH for both Candida albicans and non-Candida albicansCandida species. We also observed a statistically significant reduced ability to form biofilms in biofilm-producing strains using both methods of quantification. However, two highly biofilm-producing strains of Candida tropicalis had a very large reduction in biofilm formation. This study reinforces the idea that besides growth inhibition, E. uniflora may interfere with the expression of some virulence factors of Candida spp. and may be possibly applied in the future as a novel antifungal agent.}, } @article {pmid30240195, year = {2018}, author = {Wang, X and Wu, J and Li, P and Wang, L and Zhou, J and Zhang, G and Li, X and Hu, B and Xing, X}, title = {Microenvironment-Responsive Magnetic Nanocomposites Based on Silver Nanoparticles/Gentamicin for Enhanced Biofilm Disruption by Magnetic Field.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {41}, pages = {34905-34915}, doi = {10.1021/acsami.8b10972}, pmid = {30240195}, issn = {1944-8252}, mesh = {Animals ; Biofilms/*drug effects/growth & development ; Escherichia coli/*growth & development ; *Gentamicins/chemistry/pharmacology ; Metal Nanoparticles/*chemistry ; Mice ; NIH 3T3 Cells ; Nanocomposites/*chemistry ; *Silver/chemistry/pharmacology ; Staphylococcus aureus/*growth & development ; }, abstract = {Biofilms contribute to persistent bacterial infections as well as formidable resistances to conventional antibiotics. However, it is still a major challenge to establish an advanced antibacterial nanoplatform that can efficiently eradicate biofilms while overcoming bacterial resistances. Taking advantage of the stimuli-responsive technique and the magnetic guidance strategy, here we present a highly efficient nanoplatform for planktonic inactivation and biofilm disruption. The multilayer films consisting of antibiotic gentamicin (Gen), tannic acid, and silver nanoparticles (AgNPs) were fabricated and coated on magnetic nanoparticles via electrostatic interactions. To achieve controlled drug release and improved biocompatibility, biodegradable hyaluronic acid was capped on the outer surface as a responsive shell. In vitro release profiles suggested that the nanocomposites showed both enzyme and pH-responsive release properties. The nanoplatform could be employed as a powerful nanocarrier for small molecular Gen and AgNPs delivery and on-demand release in response to bacterial infection microenvironment. The nanocomposites also showed satisfying antibacterial capacities against planktonic Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Intriguingly, with magnetic field navigation (NdFeB, 2000 gauss), the nanocomposites could be guided to handily penetrate into S. aureus biofilm and performed dual-responsive release, showing significantly enhanced biofilm disruption. Moreover, excess reactive oxygen species production resulting from the nanocomposites contributed to the decomposition of biofilm matrix and ultimate biofilm eradication. As a consequence, the ingenious antibacterial nanoplatform could be promising for combating biofilm infections while overcoming bacterial resistances with extra environmental factors such as magnetic field.}, } @article {pmid30240117, year = {2019}, author = {Jin, X and Lee, YJ and Hong, SH}, title = {Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes.}, journal = {Journal of applied microbiology}, volume = {126}, number = {1}, pages = {300-310}, doi = {10.1111/jam.14108}, pmid = {30240117}, issn = {1365-2672}, support = {//Illinois Institute of Technology/ ; }, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Canavalia/*chemistry ; Enterohemorrhagic Escherichia coli/*drug effects ; Lectins/isolation & purification/*pharmacology ; Listeria monocytogenes/*drug effects ; }, abstract = {AIM: A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high-binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method.

METHODS AND RESULTS: ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, noncell-based mannose reduced the activity of ConA in inhibiting biofilms.

CONCLUSIONS: ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA.

ConA can be used as a promising anti-adherent and antibiofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins.}, } @article {pmid30239669, year = {2018}, author = {Petrovich, M and Chu, B and Wright, D and Griffin, J and Elfeki, M and Murphy, BT and Poretsky, R and Wells, G}, title = {Antibiotic resistance genes show enhanced mobilization through suspended growth and biofilm-based wastewater treatment processes.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {11}, pages = {}, doi = {10.1093/femsec/fiy174}, pmid = {30239669}, issn = {1574-6941}, } @article {pmid30239106, year = {2019}, author = {Vajjala, A and Biswas, D and Tay, WH and Hanski, E and Kline, KA}, title = {Streptolysin-induced endoplasmic reticulum stress promotes group A Streptococcal host-associated biofilm formation and necrotising fasciitis.}, journal = {Cellular microbiology}, volume = {21}, number = {1}, pages = {e12956}, doi = {10.1111/cmi.12956}, pmid = {30239106}, issn = {1462-5822}, mesh = {Animals ; Biofilms/*growth & development ; Cell Line ; Endoplasmic Reticulum Stress/*drug effects ; Fasciitis, Necrotizing/*microbiology ; Humans ; Mice ; Models, Theoretical ; Streptococcus pyogenes/*growth & development/*metabolism ; Streptolysins/*metabolism ; }, abstract = {Group A Streptococcus (GAS) is a human pathogen that causes infections ranging from mild to fulminant and life-threatening. Biofilms have been implicated in acute GAS soft-tissue infections such as necrotising fasciitis (NF). However, most in vitro models used to study GAS biofilms have been designed to mimic chronic infections and insufficiently recapitulate in vivo conditions along with the host-pathogen interactions that might influence biofilm formation. Here, we establish and characterise an in vitro model of GAS biofilm development on mammalian cells that simulates microcolony formation observed in a mouse model of human NF. We show that on mammalian cells, GAS forms dense aggregates that display hallmark biofilm characteristics including a 3D architecture and enhanced tolerance to antibiotics. In contrast to abiotic-grown biofilms, host-associated biofilms require the expression of secreted GAS streptolysins O and S (SLO, SLS) that induce endoplasmic reticulum (ER) stress in the host. In an in vivo mouse model, the streptolysin null mutant is attenuated in both microcolony formation and bacterial spread, but pretreatment of soft-tissue with an ER stressor restores the ability of the mutant to form wild-type-like microcolonies that disseminate throughout the soft tissue. Taken together, we have identified a new role of streptolysin-driven ER stress in GAS biofilm formation and NF disease progression.}, } @article {pmid30238361, year = {2019}, author = {Salazar-Huerta, MA and Ruiz-Ordaz, N and Galíndez-Mayer, J and García-Mena, J and Juárez-Ramírez, C}, title = {Simulation and experimental validation of a gradient feeding system for fast assessment of the kinetic behavior of a microbial consortium in a tubular biofilm reactor.}, journal = {Bioprocess and biosystems engineering}, volume = {42}, number = {1}, pages = {17-27}, doi = {10.1007/s00449-018-2009-x}, pmid = {30238361}, issn = {1615-7605}, support = {SIP-IPN 20170884//Instituto Politécnico Nacional, Mexico/ ; }, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Computer Simulation ; Culture Media ; Equipment Design ; Insecticides/chemistry ; Kinetics ; *Microbial Consortia ; Models, Theoretical ; Neonicotinoids/*chemistry ; Nitro Compounds/*chemistry ; Oxygen/chemistry ; Porosity ; }, abstract = {This study deals with the mathematical simulation and experimental validation of a gradient system for the gradual change of the imidacloprid loading rate to a tubular biofilm reactor (TBR). The strategy was used for fast studies of the kinetic and stoichiometric impact caused by the increase in the pesticide loading rate in a TBR, running in plug flow regime. Seemingly, this strategy has never been used for biokinetic and stoichiometric studies in biofilm reactors. For this purpose, a mathematical model describing the substrate transient behavior Sg(t) in a concentration gradient generator system using variable volume tanks is proposed. A second model, representing the temporary variation in the loading rate of imidacloprid to an aerated equalizer tank preceding the packed zone of the TBR, is also presented. Both models were experimentally confirmed. After the treatment of the experimental data, the kinetic and stoichiometric changes occurring in the TBR, caused by the gradual increase in the imidacloprid loading rate, were readily evaluated. Although the structure of the microbial community, at the phylum level, showed similar behavior along the tubular reactor, the stress produced by the gradual increase in imidacloprid concentration had functional consequences on the mixed microbial populations which were reflected on the stoichiometric and kinetic parameters. After increasing more than five times the imidacloprid loading rate to the TBR, the imidacloprid removal efficiency decayed about 40%, and the microbial-specific removal rate of the insecticide showed a decrease of about 30%.}, } @article {pmid30237466, year = {2018}, author = {Aliko, A and Kamińska, M and Bergum, B and Gawron, K and Benedyk, M and Lamont, RJ and Malicki, S and Delaleu, N and Potempa, J and Mydel, P}, title = {Impact of Porphyromonas gingivalis Peptidylarginine Deiminase on Bacterial Biofilm Formation, Epithelial Cell Invasion, and Epithelial Cell Transcriptional Landscape.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {14144}, pmid = {30237466}, issn = {2045-2322}, support = {R01 DE011111/DE/NIDCR NIH HHS/United States ; R37 DE011111/DE/NIDCR NIH HHS/United States ; DE022597//Foundation for the National Institutes of Health (Foundation for the National Institutes of Health, Inc.)/International ; 2016/23/B/NZ5/011469//Narodowe Centrum Nauki (National Science Centre)/International ; DE011111//Foundation for the National Institutes of Health (Foundation for the National Institutes of Health, Inc.)/International ; R01 DE022597/DE/NIDCR NIH HHS/United States ; 2014/14/E/NZ6/00162//Narodowe Centrum Nauki (National Science Centre)/International ; }, mesh = {*Biofilms ; Epithelial Cells/metabolism/*microbiology ; Gingiva/metabolism/microbiology ; Humans ; Keratinocytes/metabolism/*microbiology ; Periodontitis/metabolism/*microbiology ; Porphyromonas gingivalis/*metabolism ; Protein-Arginine Deiminases/*metabolism ; }, abstract = {Peptidylarginine deiminase (PPAD) is a virulence factor unique to pathogenic Porphyromonas species, especially P. gingivalis. Mechanistically, PPAD activity, in conjunction with Arg-specific gingipains, generates protein fragments with citrullinated C-termini. Such polypeptides are potential de novo epitopes that are key drivers of rheumatoid arthritis. This process could underlie the observed clinical association between rheumatoid arthritis and periodontitis. However, the role of PPAD in host colonization by P. gingivalis and, subsequently, in triggering periodontitis is not known. Therefore, the aim of the current study was to delineate the role of PPAD in bacterial biofilm formation, and to define whether adherence to, invasion of, and host responses to bacteria of gingival keratinocytes depend on PPAD activity. We studied these aspects using PPAD-competent and PPAD-incompetent strains of P. gingivalis, and demonstrated that neither biofilm formation nor its composition was affected by PPAD activity. Similarly, flow cytometry revealed that PPAD did not impact the ability of P. gingivalis to adhere to and, subsequently, invade keratinocytes. Network analyses of gene expression patterns, however, revealed a group of host genes that were sensitive to PPAD activity (CXCL8, IL36G, CCL20, and IL1B). These genes can be categorized as potent immune modulators belonging to the interleukin 1 system, or chemoattractants of lymphocytes and neutrophils. Thus, we conclude that PPAD, although it is a potent modulator of the immune response, does not affect bacterial biofilm formation or the ability of P. gingivalis to adhere to and invade gingival epithelial cells.}, } @article {pmid30236955, year = {2018}, author = {Tkhilaishvili, T and Lombardi, L and Klatt, AB and Trampuz, A and Di Luca, M}, title = {Bacteriophage Sb-1 enhances antibiotic activity against biofilm, degrades exopolysaccharide matrix and targets persisters of Staphylococcus aureus.}, journal = {International journal of antimicrobial agents}, volume = {52}, number = {6}, pages = {842-853}, doi = {10.1016/j.ijantimicag.2018.09.006}, pmid = {30236955}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriolysis ; Biofilms/*drug effects/*growth & development ; Colony Count, Microbial ; Extracellular Matrix/*metabolism ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development/*virology ; Microbial Viability/drug effects ; Microscopy, Confocal ; Microscopy, Fluorescence ; Polysaccharides, Bacterial/metabolism ; Staphylococcus Phages/*growth & development ; }, abstract = {Most antibiotics have limited or no activity against bacterial biofilms, whereas bacteriophages can eradicate biofilms. We evaluated whether Staphylococcus aureus-specific bacteriophage Sb-1 could eradicate biofilm, both alone and in combination with different classes of antibiotics, degrade the extracellular matrix and target persister cells. Biofilm of methicillin-resistant S. aureus (MRSA) ATCC 43300 was treated with Sb-1 alone or in (simultaneous or staggered) combination with fosfomycin, rifampin, vancomycin, daptomycin or ciprofloxacin. The matrix was visualized by confocal fluorescent microscopy. Persister cells were treated with 10[4] and 10[7] plaque-forming units (PFU)/mL Sb-1 for 3 h in phosphate-buffered saline (PBS), followed by colony-forming units (CFU) counting. Alternatively, bacteria were washed and incubated in fresh brain heart infusion (BHI) medium and bacterial growth assessed after a further 24 h. Pretreatment with Sb-1 followed by the administration of subinhibitory concentrations of antibiotic caused a synergistic effect in eradicating MRSA biofilm. Sb-1 determined a dose-dependent reduction of matrix exopolysaccharide. Sb-1 at 10[7] PFU/mL showed direct killing activity on ≈ 5 × 10[5] CFU/mL persisters. However, even a lower titer had lytic activity when phage-treated persister cells were inoculated in fresh medium, reverting to a normal-growing phenotype. This study provides valuable data on the enhancing effect of Sb-1 on antibiotic efficacy, exhibiting specific antibiofilm features. Sb-1 can degrade the MRSA polysaccharide matrix and target persister cells and is therefore suitable for treatment of biofilm-associated infections.}, } @article {pmid30235341, year = {2018}, author = {Beshiru, A and Igbinosa, IH and Igbinosa, EO}, title = {Biofilm formation and potential virulence factors of Salmonella strains isolated from ready-to-eat shrimps.}, journal = {PloS one}, volume = {13}, number = {9}, pages = {e0204345}, pmid = {30235341}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Extracellular Space/metabolism ; Hydrophobic and Hydrophilic Interactions ; Phenotype ; Salmonella/cytology/*metabolism/*physiology ; Seafood/*microbiology ; Virulence Factors/*metabolism ; }, abstract = {Salmonella species is an important foodborne pathogen with the non-typhoidal serovars such as Enteritidis and Typhimurium as the most predominant strains. This study examines the biofilm formation, phenotypic virulence factors and cell surface characteristics of Salmonella strains from ready-to-eat shrimps. The ready-to-eat shrimps were obtained from open markets between November 2016 and October 2017 in Edo and Delta States, Nigeria. The occurrence of Salmonella strains in this study was 210/1440 (14.58%) of the ready-to-eat shrimp's samples. The identified strains comprise of Salmonella Enteritidis 11, Salmonella Typhimurium 14 and other Salmonella spp. 20. The 45 identified Salmonella strains revealed the following virulence properties: swimming and swarming motility 45(100%); S-layer 39(86.67%); haemolytic activity 40(88.89%); lipase activity 43(95.56%); protease activity 43(95.56%); gelatinase production 43(95.56%); and DNA degrading activity 41(91.11%). The variation in the formation of biofilm-based on the diversity of Salmonella species was observed with higher percentage of Salmonella Typhimurium strains as strong biofilms producers under different environmental conditions. For surface hydrophobicity using bacterial adherence to hydrocarbons, 25(55.56%) were hydrophilic while 20(44.44%) were moderately hydrophobic from the 45 Salmonella isolates. Using salting aggregation test for surface hydrophobicity, all selected isolates 45(100%) was hydrophilic. Autoaggregation index for the 12 selected Salmonella isolates ranged from 15.2-47.2%, while the autoaggragation index for the 12 selected test bacteria ranged from 26.2-71.3%. Coaggragation between the 12 selected test bacteria and 12 Salmonella isolates ranged from 12.5-81.0%. The occurrence of pathogenic species of Salmonella from ready-to-eat shrimps could be detrimental to the consumers. Findings on the physiological conditions of biofilms formed by the foodborne pathogenic Salmonella and the cell surface characteristics therein are crucial for the advancement of methods for controlling Salmonella from ready-to-eat foods.}, } @article {pmid30965904, year = {2017}, author = {Fleming, G and Aveyard, J and Fothergill, JL and McBride, F and Raval, R and D'Sa, RA}, title = {Nitric Oxide Releasing Polymeric Coatings for the Prevention of Biofilm Formation.}, journal = {Polymers}, volume = {9}, number = {11}, pages = {}, pmid = {30965904}, issn = {2073-4360}, support = {EP/MO27325/1//EPSRC/ ; }, abstract = {The ability of nitric oxide (NO)-releasing polymer coatings to prevent biofilm formation is described. NO-releasing coatings on (poly(ethylene terephthalate) (PET) and silicone elastomer (SE)) were fabricated using aminosilane precursors. Pristine PET and SE were oxygen plasma treated, followed by immobilisation of two aminosilane molecules: N-(3-(trimethoxysilyl)propyl)diethylenetriamine (DET3) and N-(3-trimethoxysilyl)propyl)aniline (PTMSPA). N-diazeniumdiolate nitric oxide donors were formed at the secondary amine sites on the aminosilane molecules producing NO-releasing polymeric coatings. The NO payload and release were controlled by the aminosilane precursor, as DET3 has two secondary amine sites and PTMSPA only one. The antibacterial efficacy of these coatings was tested using a clinical isolate of Pseudomonas aeruginosa (PA14). All NO-releasing coatings in this study were shown to significantly reduce P. aeruginosa adhesion over 24 h with the efficacy being a function of the aminosilane modification and the underlying substrate. These NO-releasing polymers demonstrate the potential and utility of this facile coating technique for preventing biofilms for indwelling medical devices.}, } @article {pmid30895061, year = {2017}, author = {Umezawa, T and Ryu, M and Tasaka, A and Ueda, T and Ishihara, K and Sakurai, K}, title = {Effect of water containing organic acids on aspiration pneumonia-causative bacteria in the biofilm on the tooth surface.}, journal = {Journal of dental sciences}, volume = {12}, number = {3}, pages = {268-274}, pmid = {30895061}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: The tooth surface is a source of oral microbes in dentulous individuals, it is difficult for elderly people requiring nursing care to perform mechanical tooth cleaning by themselves. The objective of this study was to investigate the antimicrobial effect of water containing organic acids (WOA) made by some organic acids as food additives on chemical cleaning for elderly people on aspiration pneumonia-causative bacteria in the biofilm on the tooth surface.

MATERIALS AND METHODS: Ninety-six specimens made from bovine incisors were divided into four groups and incubated with one of four aspiration pneumonia-causative bacteria. Each group was further divided into six subgroups according to treatment as follows: control group (DW), chlorhexidine gluconate solution group (CHX), WOA group (WOA), ultrasonic treatment in distilled water group (DW-U), ultrasonic treatment in chlorhexidine gluconate solution group (CHX-U) or ultrasonic treatment in WOA group (WOA-U). After treatment, the levels of viable microbes in the biofilm were evaluated by quantitative adenosine triphosphate analysis and compared among the six groups.

RESULTS: For every evaluated microbe, there were significant differences between DW and WOA, and DW and WOA-U. However, there was no significant difference among the WOA, DW-U, CHX-U and WOA-U groups. These results suggested that the antimicrobial effect of WOA on microbes attached to the tooth surface was similar to that of ultrasonic cleaning.

CONCLUSION: WOA has an antimicrobial effect on microbes in the biofilm on the tooth surface.}, } @article {pmid30263642, year = {2017}, author = {Kwon, M and Hussain, MS and Oh, DH}, title = {Biofilm formation of Bacillus cereus under food-processing-related conditions.}, journal = {Food science and biotechnology}, volume = {26}, number = {4}, pages = {1103-1111}, pmid = {30263642}, issn = {2092-6456}, abstract = {This study aims to understand the biofilm formation abilities of eight Bacillus cereus strains under food-industry-related conditions. Biofilms were grown in microtiter plates in tryptic soy broth (TSB) or brain heart infusion (BHI) at 30 °C for 24 or 48 h and quantified via the crystal violet assay. A significantly larger of biofilm was formed in TSB than in BHI after 48 h. Selected strains were used to test biofilm formation under food-related conditions produced by different surfaces (e.g., stainless steel, plastic, or glass), temperatures (25 or 30 °C), carbon sources, (glucose or glycerol) and NaCl. Biofilm formation appeared to be affected by surface properties, temperature, and carbon sources. A larger biofilm was formed on stainless steel at 30 °C compared to plastic and glass surfaces at 25 and 30 °C. Moreover, addition of glucose in combination with NaCl in TSB produced significantly larger biofilm than glucose, glycerol and/or NaCl. These results indicate that food-industry-related conditions could promote B. cereus biofilm formation, which is relevant to food safety.}, } @article {pmid30695540, year = {2017}, author = {Tsarev, VN and Ippolitov, EV and Nikolaeva, EN}, title = {PREVALENCE OF GENETIC MARKERS OF RESISTANCE TO ANTIBIOTICS IN BIOFILM-FORMING STRAINS OF OBLIGATE AND ELECTIVE ANAEROBES.}, journal = {Zhurnal mikrobiologii, epidemiologii i immunobiologii}, volume = {}, number = {2}, pages = {74-80}, pmid = {30695540}, issn = {0372-9311}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria, Anaerobic/*physiology ; *Biofilms/drug effects/growth & development ; *Drug Resistance, Bacterial/drug effects/genetics ; Genetic Markers ; }, abstract = {AIM: Comparative study of frequency of detection of genetic markers of resistance to antibiotics forming in anaerobic bacteria under the conditions of mixed biofilms in a clinical setting and comparison of data of phenotypic and genotypic methods of study.

MATERIALS AND METHODS: 66 strains of bacteria forming biofilm with PCR detection of antibiotics were studied: Streptococcus sanguinis, Streptococcus salivarius, Staphylococcus aureus, Staphylococcus epi- dermidis, Enterococcusfaecalis, Klebsiellapneumoniae, Pseudomonas aeruginosa and anaero- bic pathogens - Porphyromonasgingivalis, Tannerella forsythia, Parvinonas micra, Prevotella intermedia. Modelling of microbial biofilms in vitro and scanning electron microscopy were carried out.

RESULTS: The studied strains of resident and pathogenic microbiota were established to have genes that code resistance to P-lactam antibiotics; carbapenems, macrolides, tetra- cyclines. Genetic markers of resistance to P-lactam antibiotics (STX-M 14 MECA - cepha- losporines), including carbapenems.(VIM and NDM, but not Oxa-48), glycopeptides (VanA and VanB), macrolides (ERM), tetracycline (Tet) and QNRB plasmids (fluoroquinolones) were detected in strains by PCR.

CONCLUSION: The most frequently used preparations in dental practice - metronidazole and lincomycin (for the last 20 - 30 years) have shown the highest number of resistant strains - 52.3 and 22.7%, respectively. The frequency of detection of genetic markers of resistance to other studied preparations did not exceed 2.5 - 11.4%. Minimal quantity of resistant strains of anaerobic bacteria was detected for carbapenems and fluoroquinolones.}, } @article {pmid30620537, year = {2017}, author = {Shipitsyna, IV and Osipova, EV}, title = {[THE BIOFILM FORMATION ABILITY OF STRAINS SERRATIA SPP., SEPARATED FROM WOUNDS OF PATIENTS WITH CHRONIC OSTEOMYELITIS IN MONO-CULTURES AND IN COMPOSITION OF ASSOCIATION OF MICROORGANISMS HARVESTED IN VITRO].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {62}, number = {3}, pages = {188-192}, pmid = {30620537}, issn = {0869-2084}, mesh = {*Bacterial Adhesion ; Biofilms/growth & development ; Fistula/microbiology ; Humans ; Inflammation/*microbiology/pathology ; Osteomyelitis/*microbiology/pathology ; Pseudomonas aeruginosa/growth & development/isolation & purification ; Quorum Sensing ; Serratia marcescens/*growth & development/isolation & purification/pathogenicity ; }, abstract = {The article presents analysis of characteristics of 7 clinical strains of Serratia marcescens separated from fistulas in pre-operational period and from nidus of inflammation during operations in 2013-2015. in 7 patients with chronic osteomyelitis of long tubular bones. The bacteria S.marcescens are separated in one patient in monoculture and in 6 patients in composition of associations: S.marcescens + S.warneri + P.aeruginosa (n=1); S.marcescens + S.aureus (n=4); S.marcescens + M.morganii (n=1). According phometric analysis, strains of S.marcescens were characterized by average ability for biofilm formation on the surfaces of polystyrene dishes and cover glass that is substantiated by values of optic density and is conformed to data of their adhesion activity. The biofilm formation ability of association of microorganisms (S.marcescens + P.aeruginosa, S.marcescens + M.morgani) already after 24 hours of experiment were correspondingly higher in 1.4 and 1.2 times of levels of biofilm formation in monocultures. The activity of biofilm formation of association (S.marcescens + S.aureus) on the first day of experiment was low. However, after 48 hours a significant growth of biofilm was observed that is substantiated by values of optical density. The results of study demonstrated ability of all clinical strains of S.marcescens separated from osteomyelitis nidus to adhesion on surface of erythrocytes and to biofilm formation on abiotic surfaces (polystyrene and glass) both in monoculture and associations with other microorganisms. In consideration that microbial films play leading role in chronization of infectious diseases it is necessary to be aware of seriousness of etiologic role of S.marcescens in development of osteomyelitis as a pathogen.}, } @article {pmid30894991, year = {2016}, author = {Bachtiar, EW and Dewiyani, S and Surono Akbar, SM and Bachtiar, BM}, title = {Inhibition of Candida albicans biofilm development by unencapsulated Enterococcus faecalis cps2.}, journal = {Journal of dental sciences}, volume = {11}, number = {3}, pages = {323-330}, pmid = {30894991}, issn = {2213-8862}, abstract = {BACKGROUND/PURPOSE: In the oral environment, Candida albicans interacts with many bacteria, including Enterococcus faecalis. We investigated the susceptibility of C. albicans biofilm development to the presence of unencapsulated E. faecalis cps2 in comparison with reference strains (E. faecalis ATCC 29212) or their respective spent medium (collected at 6 hours).

MATERIAL AND METHODS: Crystal violet stain was used to measure the total biofilm mass, whereas quantitative real-time polymerase chain reaction was used to analyze the change in expression of the mRNA of hypha morphology (ALS1 and ALS3) and biofilm maturation (EFB1).

RESULTS: At the intermediate stage, C. albicans resisted the presence of each E. faecalis strain tested and their spent medium. However, at the maturation stage, the unencapsulated strain was stronger in reducing C. albicans biofilms than the reference strain (P < 0.05). At this maturation stage, the transcription levels of each gene tested decreased in the presence of either E. faecalis strains or their respective spent medium. The unencapsulated strain was more pronounced in reducing ALS1/ALS3 expression, whereas the respective spent medium had a similar capability to restrict the expression of EFB1.

CONCLUSION: This study showed, the unencapsulated strain is more effective in inhibiting C. albicans biofilm development compared with the reference strains. In contrast, the secreted molecules produced by each strain tested are necessary in controlling the growths of C. albicans biofilm.}, } @article {pmid30263318, year = {2016}, author = {Kim, BR and Bae, YM and Hwang, JH and Lee, SY}, title = {Biofilm formation and cell surface properties of Staphylococcus aureus isolates from various sources.}, journal = {Food science and biotechnology}, volume = {25}, number = {2}, pages = {643-648}, pmid = {30263318}, issn = {2092-6456}, abstract = {This study investigated biofilm formation, cell surface hydrophobicity, colony spreading, and slime production for 112 Staphylococcus aureus strains isolated from various sources (leaf vegetables, pea leaf, perilla leaf, Kim-bab, person, and animal). When biofilm formation was classified by origin, S. aureus isolated from animal origin showed a significantly higher level of biofilm formation than others (p≤0.05). When S. aureus groups with different levels of biofilm formation (very strong, strong, moderate, and weak) were evaluated for the correlation with cell surface properties, there was a positive correlation between biofilm formation and hydrophobicity (r=0.926). Biofilm formation and colony spreading on tryptic soy broth (without dextrose) also showed positive correlation (r=0.863). In contrast, biofilm formation and slime production were negatively correlated (r=-0.973). Based on these results, the biofilm forming ability of S. aureus differs depending on their origin and might be affected by cell surface properties such as cell surface hydrophobicity.}, } @article {pmid30979226, year = {2016}, author = {Groza, A and Ciobanu, CS and Popa, CL and Iconaru, SL and Chapon, P and Luculescu, C and Ganciu, M and Predoi, D}, title = {Structural Properties and Antifungal Activity against Candida albicans Biofilm of Different Composite Layers Based on Ag/Zn Doped Hydroxyapatite-Polydimethylsiloxanes.}, journal = {Polymers}, volume = {8}, number = {4}, pages = {}, pmid = {30979226}, issn = {2073-4360}, support = {Core program PN 16-48 (MS-FISCOMAT)//Romanian Ministry of Education/ ; Core program PN 16-47-02 (LAPLAS IV)//Romanian Ministry of Education/ ; }, abstract = {Modern medicine is still struggling to find new and more effective methods for fighting off viruses, bacteria and fungi. Among the most dangerous and at times life-threatening fungi is Candida albicans. Our work is focused on surface and structural characterization of hydroxyapatite, silver doped hydroxyapatite and zinc doped hydroxyapatite deposited on a titanium substrate previously coated with polydimethylsiloxane (HAp-PDMS, Ag:HAp-PDMS, Zn:HAp-PDMS) by different techniques: Scanning Electron Microscopy (SEM), Glow Discharge Optical Emission Spectroscopy (GDOES) and Fourier Transform Infrared Spectroscopy (FTIR). The morphological studies revealed that the use of the PDMS polymer as an interlayer improves the quality of the coatings. The structural characterizations of the thin films revealed the basic constituents of both apatitic and PDMS structure. In addition, the GD depth profiles indicated the formation of a composite material as well as the successful embedding of the HAp, Zn:HAp and Ag:HAp into the polymer. On the other hand, in vitro evaluation of the antifungal properties of Ag:HAp-PDMS and Zn:HAp-PDMS demonstrated the fungicidal effects of Ag:HAp-PDMS and the potential antifungal effect of Zn:HAp-PDMS composite layers against C. albicans biofilm. The results acquired in this research complete previous research on the potential use of new complex materials produced by nanotechnology in biomedicine.}, } @article {pmid30727459, year = {2012}, author = {Worthington, RJ and Rogers, SA and Huigens, RW and Melander, C and Ritchie, DF}, title = {Foliar-Applied Small Molecule that Suppresses Biofilm Formation and Enhances Control of Copper-Resistant Xanthomonas euvesicatoria on Pepper.}, journal = {Plant disease}, volume = {96}, number = {11}, pages = {1638-1644}, doi = {10.1094/PDIS-02-12-0190-RE}, pmid = {30727459}, issn = {0191-2917}, abstract = {We report a small molecule additive, a member of the 2-aminoimidazole (2AI) group that is an analogue of the marine sponge natural product oroidin that suppresses resistance of Xanthomonas euvesicatoria to copper and decreases biofilm formation in an in vitro system. In laboratory experiments, 2AI combined with copper reduced both bacterial multiplication in broth and bacterial recovery on pepper leaf discs of a copper-resistant strain of X. euvesicatoria to a level close to that of a copper-sensitive strain. Compound 2AI used alone exhibited minimal bactericidal activity. In 3 years of field experiments, when combined with a copper-containing material, copper hydroxide (Kocide 3000), and other antibacterial materials, these spray mixtures resulted in decreased bacterial spot foliar disease and increased fruit yields using hybrid bell pepper (Capsicum annuum) cultivars and copper-resistant strains of X. euvesicatoria. This study demonstrates the concept for using small molecules as additives to antibacterial compounds at nonbactericidal concentrations under field conditions that, in the laboratory, were demonstrated to suppress bacterial biofilms and copper-resistant strains.}, } @article {pmid30823237, year = {2002}, author = {Marques, LLR and Ceri, H and Manfio, GP and Reid, DM and Olson, ME}, title = {Characterization of Biofilm Formation by Xylella fastidiosa In Vitro.}, journal = {Plant disease}, volume = {86}, number = {6}, pages = {633-638}, doi = {10.1094/PDIS.2002.86.6.633}, pmid = {30823237}, issn = {0191-2917}, abstract = {Xylella fastidiosa colonizes the xylem of various host plants, causing economically important diseases such as Pierce's disease in grapevine and citrus variegated chlorosis (CVC) in sweet oranges. The aggregative nature of this bacterium has been extensively documented in the plant xylem and the insect's foregut. Structured communities of microbial aggregates enclosed in a self-produced polymeric matrix and attached to a surface are defined as biofilms. In this study, we characterized biofilm formation by X. fastidiosa through the use of a novel in vitro assay for studying biofilm growth in a potential mimic system of what might occur in planta. We used wood, a xylem rich material, as a surface for bacterial attachment and biofilm formation, under shear force. We demonstrated that X. fastidiosa strains isolated from various hosts formed biofilm on wood in this in vitro assay. Different biofilm morphology was detected, which seems to vary according to the strain tested and microenvironmental conditions analyzed. We observed that strains from different hosts could be grouped according to three parameters: biofilm morphology, the ability to form clumps in liquid culture, and the ability to attach to glass surfaces. We hypothesize that biofilm formation is likely a major virulence factor in diseases related to X. fastidiosa, bringing a new perspective for disease treatment.}, } @article {pmid31084051, year = {1993}, author = {Mosteller, TM and Bishop, JR}, title = {Sanitizer Efficacy Against Attached Bacteria in a Milk Biofilm.}, journal = {Journal of food protection}, volume = {56}, number = {1}, pages = {34-41}, doi = {10.4315/0362-028X-56.1.34}, pmid = {31084051}, issn = {1944-9097}, abstract = {Pseudomonas fluorescens , Yersinia enterocolitica , and Listeria monocytogenes were shown to readily attach to both rubber and Teflon[®] surfaces. Sanitizer efficacy testing done in the laboratory with nonadherent bacteria could lead to false assumptions as to the sanitizer's true effectiveness under processing conditions where cells may be attached. The objectives in this study were: (a) evaluate the efficacy of in-use concentrations of sanitizers on bacteria attached to gasket materials, (b) compare bacterial attachment to rubber and Teflon® gaskets, (c) examine different methods of enumeration, and (d) compare sanitizer efficacy on attached and suspended bacteria. The goal reduction for all of the sanitizers tested was ≥3 log cycles or 99.9%. Results indicated that iodophor, hypochlorite, acid anionic, peroxyacetic acid, fatty acid, and quaternary ammonium sanitizers failed to provide an adequate reduction in the numbers of attached bacteria at levels of 10[4] to 10[5/]mm[2] in most cases. The test organisms attached in slightly higher numbers to the rubber surface versus Teflon®. Plate counts, impedance microbiology, and the direct epifluorescent filter technique were tested as methods of enumeration. Impedance microbiology was the best method of enumeration, since it allowed the estimation of both reversibly and irreversibly attached bacteria. The efficacy of sanitizers versus a bacterial suspensions resulted in a ≥ 5 log-cycle reduction. The same concentrations were relatively ineffective against the attached bacteria. The goal reduction was reached on the Teflon® surface with the iodophor, hypochlorite, and fatty acid sanitizers with a log-cycle reduction in the number of Yersinia enterocolitica of 3.09, 3.19, and 3.31, respectively. Pseudomonas fluorescens was reduced by 3.16 on both the rubber and Teflon® surfaces when exposed to the hypochlorite sanitizer.}, } @article {pmid30210788, year = {2018}, author = {Mubarak, Z and Humaira, A and Gani, BA and Muchlisin, ZA}, title = {Preliminary study on the inhibitory effect of seaweed Gracilaria verrucosa extract on biofilm formation of Candida albicans cultured from the saliva of a smoker.}, journal = {F1000Research}, volume = {7}, number = {}, pages = {684}, pmid = {30210788}, issn = {2046-1402}, mesh = {Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Gracilaria/*chemistry ; Humans ; Plant Extracts/*pharmacology ; Saliva/*microbiology ; *Smokers ; Steroids/isolation & purification/pharmacology ; Tannins/pharmacology ; Terpenes/isolation & purification/pharmacology ; }, abstract = {Background:Candida albicans is an opportunistic fungus that might infect the oral cavity. Increased colony numbers of C. albicans in the mouth can be caused by multiple factors, such as smoking, weakened immune system, antibiotics use and immune-compromised condition. Smoking can increase expression of virulence factors of C. albicans and make it stronger. One virulence factor of C. albicans is biofilm formation. The ability of creating biofilm makes C. albicans more tolerant to commercial antifungal agents. The objective of this preliminary study was to examine the ability of the seaweed G.verrucosa extracts to inhibit the formation of biofilm by C. albicans isolated from the saliva of a smoker. Methods: The extract of G. verrucosa was prepared by maceration using 96% methanol and subjected for phytochemical analysis. C. albicans was isolated from the saliva of a smoker who voluntarily participated in the study after providing informed consent. In triplicate, the fungus was cultured in the growth medium containing increased concentrations of G. verrucosa (6.25, 12.5, 25, 50, 75 and 100%).The same reaction using fluconazole 0.31 µg/ml C. albicans was prepared as positive control. Biofilm formation was accessed based on optical density of cell mixtures using an ELISA reader. The data obtained were subjected to Kruskal-Wallis test at a significance limit of 0.05. Results: Methanol extract of seaweed G. verrucosa contained three bio-active compounds namely steroids, terpenoid, and tannins. Inhibitory activity of seaweed extracts on C. albicans biofilm formation increased as their concentration increased. The highest inhibitory effect was recorded at fungus culture treated with seaweed concentration of 25% at 24 hours of time exposure. Conclusions: Seaweed G. verrucosa extract contained steroids, terpenoids and tannins that were able to effectively inhibit the formation of biofilm by C. albicans at the concentration of 25% after 24 hours of time exposure.}, } @article {pmid30235145, year = {2018}, author = {Martins, DP and Leetanasaksakul, K and Barros, MT and Thamchaipenet, A and Donnelly, W and Balasubramaniam, S}, title = {Molecular Communications Pulse-Based Jamming Model for Bacterial Biofilm Suppression.}, journal = {IEEE transactions on nanobioscience}, volume = {17}, number = {4}, pages = {533-542}, doi = {10.1109/TNB.2018.2871276}, pmid = {30235145}, issn = {1558-2639}, mesh = {*Bacterial Physiological Phenomena ; Bacterial Proteins/metabolism ; *Biofilms ; Computers, Molecular ; Databases, Protein ; Models, Biological ; Proteomics ; Quorum Sensing/*physiology ; Signal Transduction/*physiology ; Staphylococcus aureus/physiology ; Synthetic Biology/*methods ; }, abstract = {Studies have recently shown that the bacteria survivability within biofilms is responsible for the emergence of superbugs. The combat of bacterial infections, without enhancing its resistance to antibiotics, includes the use of nanoparticles to quench the quorum sensing of these biofilm-forming bacteria. Several sequential and parallel multi-stage communication processes are involved in the formation of biofilms. In this paper, we use proteomic data from a wet lab experiment to identify the communication channels that are vital to these processes. We also identified the main proteins from each channel and propose the use of jamming signals from synthetically engineered bacteria to suppress the production of those proteins. This biocompatible technique is based on synthetic biology and enables the inhibition of biofilm formation. We analyze the communications performance of the jamming process by evaluating the path loss for a number of conditions that include different engineered bacterial population sizes, distances between the populations, and molecular signal power. Our results show that sufficient molecular pulse-based jamming signals are able to prevent the biofilm formation by creating lossy communications channels (almost -3 dB for certain scenarios). From these results, we define the main design parameters to develop a fully operational bacteria-based jamming system.}, } @article {pmid30232623, year = {2019}, author = {Schmidt, JC and Astasov-Frauenhoffer, M and Waltimo, T and Weiger, R and Walter, C}, title = {Influence of the amplitude of different side-to-side toothbrushes on noncontact biofilm removal.}, journal = {Clinical oral investigations}, volume = {23}, number = {4}, pages = {1951-1957}, pmid = {30232623}, issn = {1436-3771}, mesh = {*Biofilms ; Fusobacterium nucleatum ; Porphyromonas gingivalis ; Streptococcus sanguis ; Toothbrushing/*instrumentation ; }, abstract = {OBJECTIVES: To investigate the impact of the lateral deflection of toothbrush bristles (amplitude) of three side-to-side toothbrushes for noncontact biofilm removal in an artificial interdental space model.

MATERIALS AND METHODS: A three-species biofilm (Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sanguinis) was formed in vitro on protein-coated titanium disks. A flow chamber system was combined with a static biofilm growth model. The amplitudes of three commercial side-to-side toothbrushes were evaluated by means of a dose response analysis. The amplitudes were decreased in steps (100%, 85%, 70%, 55%, and 40%). Subsequently, the biofilm-coated substrates were exposed to the toothbrushes. The biofilms were analyzed with confocal laser scanning microscope images and measured using volumetric analyses.

RESULTS: The predictability of interdental biofilm reduction differed among the toothbrushes. A lower variety in the results of repeated experiments occurred in toothbrush C compared to toothbrushes A and B. Toothbrush C obtained highest percentage of biofilm reduction by 85% of amplitude power setting (median biofilm reduction 76%). Decreasing the amplitude from 85 to 40% resulted in reduced biofilm reduction (p = 0.029). In contrast, no significance could be observed for the differences of the tested amplitudes within toothbrushes A and B (p > 0.05). Between the toothbrushes, a significant difference in interdental biofilm reduction was found between C-A (p = 0.029) and C-B (p = 0.029) with amplitude of 85%.

CONCLUSIONS: The amplitude of one of the investigated side-to-side toothbrushes affected the biofilm reduction predictably in an interdental space model.

CLINICAL RELEVANCE: Within certain toothbrushes, a specific amplitude power setting may demonstrate beneficial effects on noncontact biofilm removal.}, } @article {pmid30231554, year = {2018}, author = {Chan, WT and Domenech, M and Moreno-Córdoba, I and Navarro-Martínez, V and Nieto, C and Moscoso, M and García, E and Espinosa, M}, title = {The Streptococcus pneumoniaeyefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation.}, journal = {Toxins}, volume = {10}, number = {9}, pages = {}, pmid = {30231554}, issn = {2072-6651}, mesh = {Antitoxins/*physiology ; Bacterial Toxins/*genetics ; *Biofilms ; Operon ; Oxidative Stress ; Streptococcus pneumoniae/*physiology ; }, abstract = {Type II (proteic) toxin-antitoxin systems (TAs) are widely distributed among bacteria and archaea. They are generally organized as operons integrated by two genes, the first encoding the antitoxin that binds to its cognate toxin to generate a harmless protein[-]protein complex. Under stress conditions, the unstable antitoxin is degraded by host proteases, releasing the toxin to achieve its toxic effect. In the Gram-positive pathogen Streptococcus pneumoniae we have characterized four TAs: pezAT, relBE, yefM-yoeB, and phD-doc, although the latter is missing in strain R6. We have assessed the role of the two yefM-yoeB and relBE systems encoded by S. pneumoniae R6 by construction of isogenic strains lacking one or two of the operons, and by complementation assays. We have analyzed the phenotypes of the wild type and mutants in terms of cell growth, response to environmental stress, and ability to generate biofilms. Compared to the wild-type, the mutants exhibited lower resistance to oxidative stress. Further, strains deleted in yefM-yoeB and the double mutant lacking yefM-yoeB and relBE exhibited a significant reduction in their ability for biofilm formation. Complementation assays showed that defective phenotypes were restored to wild type levels. We conclude that these two loci may play a relevant role in these aspects of the S. pneumoniae lifestyle and contribute to the bacterial colonization of new niches.}, } @article {pmid30230671, year = {2018}, author = {Abouelhassan, Y and Zhang, Y and Jin, S and Huigens, RW}, title = {Transcript Profiling of MRSA Biofilms Treated with a Halogenated Phenazine Eradicating Agent: A Platform for Defining Cellular Targets and Pathways Critical to Biofilm Survival.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {57}, number = {47}, pages = {15523-15528}, pmid = {30230671}, issn = {1521-3773}, support = {R35 GM128621/GM/NIGMS NIH HHS/United States ; R35GM128621/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms/drug effects ; Halogenation ; Humans ; Iron/metabolism ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/*physiology ; Phenazines/chemistry/pharmacology ; Signal Transduction/drug effects ; Staphylococcal Infections/drug therapy/microbiology ; *Transcriptome/drug effects ; }, abstract = {Bacterial biofilms are surface-attached communities of non-replicating bacteria innately tolerant to antibiotics. Biofilms display differential gene expression profiles and physiologies as compared to their planktonic counterparts; however, their biology remains largely unknown. In this study, we used a halogenated phenazine (HP) biofilm eradicator in transcript profiling experiments (RNA-seq) to define cellular targets and pathways critical to biofilm viability. WoPPER analysis with time-course validation (RT-qPCR) revealed that HP-14 induces rapid iron starvation in MRSA biofilms, as evident by the activation of iron-acquisition gene clusters in 1 hour. Serine proteases and oligopeptide transporters were also found to be up-regulated, whereas glycolysis, arginine deiminase, and urease gene clusters were down-regulated. KEGG analysis revealed that HP-14 impacts metabolic and ABC transporter functional pathways. These findings suggest that MRSA biofilm viability relies on iron homeostasis.}, } @article {pmid30228377, year = {2018}, author = {Rupf, S and Laczny, CC and Galata, V and Backes, C and Keller, A and Umanskaya, N and Erol, A and Tierling, S and Lo Porto, C and Walter, J and Kirsch, J and Hannig, M and Hannig, C}, title = {Comparison of initial oral microbiomes of young adults with and without cavitated dentin caries lesions using an in situ biofilm model.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {14010}, pmid = {30228377}, issn = {2045-2322}, support = {RU 866/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/International ; HA 2718/11-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/International ; HA 5192/7-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/International ; }, mesh = {Adult ; Animals ; Biofilms/*growth & development ; Biomarkers/*analysis ; Case-Control Studies ; Cattle ; Dental Caries/genetics/*microbiology/pathology ; Dental Enamel/metabolism/*microbiology/pathology ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Male ; Microbiota/*genetics ; Mouth/*microbiology ; Saliva/*microbiology ; Young Adult ; }, abstract = {Dental caries is caused by acids released from bacterial biofilms. However, the in vivo formation of initial biofilms in relation to caries remains largely unexplored. The aim of this study was to compare the oral microbiome during the initial phase of bacterial colonization for individuals with (CC) and without (NC) cavitated dentin caries lesions. Bovine enamel slabs on acrylic splints were worn by the volunteers (CC: 14, NC: 13) for in situ biofilm formation (2 h, 4 h, 8 h, 1 ml saliva as reference). Sequencing of the V1/V2 regions of the 16S rRNA gene was performed (MiSeq). The relative abundances of individual operational taxonomic units (OTUs) were compared between samples from the CC group and the NC group. Random forests models were furthermore trained to separate the groups. While the overall heterogeneity did not differ substantially between CC and NC individuals, several individual OTUs were found to have significantly different relative abundances. For the 8 h samples, most of the significant OTUs showed higher relative abundances in the CC group, while the majority of significant OTUs in the saliva samples were more abundant in the NC group. Furthermore, using OTU signatures enabled a separation between both groups, with area-under-the-curve (AUC) values of ~0.8. In summary, the results suggest that initial oral biofilms provide the potential to differentiate between CC and NC individuals.}, } @article {pmid30228240, year = {2018}, author = {Brockman, KL and Azzari, PN and Branstool, MT and Atack, JM and Schulz, BL and Jen, FE and Jennings, MP and Bakaletz, LO}, title = {Epigenetic Regulation Alters Biofilm Architecture and Composition in Multiple Clinical Isolates of Nontypeable Haemophilus influenzae.}, journal = {mBio}, volume = {9}, number = {5}, pages = {}, pmid = {30228240}, issn = {2150-7511}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC015688/DC/NIDCD NIH HHS/United States ; }, mesh = {Alkalies ; Biofilms/*growth & development ; *Epigenesis, Genetic ; *Gene Expression Regulation, Bacterial ; Haemophilus Infections/microbiology ; Haemophilus influenzae/*genetics ; Humans ; Hydrogen-Ion Concentration ; Otitis Media/microbiology ; Phenotype ; Regulon/genetics ; }, abstract = {Biofilms play a critical role in the colonization, persistence, and pathogenesis of many human pathogens. Multiple mucosa-associated pathogens have evolved a mechanism of rapid adaptation, termed the phasevarion, which facilitates a coordinated regulation of numerous genes throughout the bacterial genome. This epigenetic regulation occurs via phase variation of a DNA methyltransferase, Mod. The phasevarion of nontypeable Haemophilus influenzae (NTHI) significantly affects the severity of experimental otitis media and regulates several disease-related processes. However, the role of the NTHI phasevarion in biofilm formation is unclear. The present study shows that the phasevarions of multiple NTHI clinical isolates regulate in vitro biofilm formation under disease-specific microenvironmental conditions. The impact of phasevarion regulation was greatest under alkaline conditions that mimic those known to occur in the middle ear during disease. Under alkaline conditions, NTHI strains that express the ModA2 methyltransferase formed biofilms with significantly greater biomass and less distinct architecture than those formed by a ModA2-deficient population. The biofilms formed by NTHI strains that express ModA2 also contained less extracellular DNA (eDNA) and significantly less extracellular HU, a DNABII DNA-binding protein critical for biofilm structural stability. Stable biofilm structure is critical for bacterial pathogenesis and persistence in multiple experimental models of disease. These results identify a role for the phasevarion in regulation of biofilm formation, a process integral to the chronic nature of many infections. Understanding the role of the phasevarion in biofilm formation is critical to the development of prevention and treatment strategies for these chronic diseases.IMPORTANCE Upper respiratory tract infections are the number one reason for a child to visit the emergency department, and otitis media (middle ear infection) ranks third overall. Biofilms contribute significantly to the chronic nature of bacterial respiratory tract infections, including otitis media, and make these diseases particularly difficult to treat. Several mucosa-associated human pathogens utilize a mechanism of rapid adaptation termed the phasevarion, or phasevariable regulon, to resist environmental and host immune pressures. In this study, we assessed the role of the phasevarion in regulation of biofilm formation by nontypeable Haemophilus influenzae (NTHI), which causes numerous respiratory tract diseases. We found that the NTHI phasevarion regulates biofilm structure and critical biofilm matrix components under disease-specific conditions. The findings of this work could be significant in the design of improved strategies against NTHI infections, as well as diseases due to other pathogens that utilize a phasevarion.}, } @article {pmid30227228, year = {2018}, author = {Capote-Bonato, F and Sakita, KM and de Oliveira, AG and Bonfim-Mendonça, PS and Crivellenti, LZ and Negri, M and Estivalet Svidzinski, TI}, title = {In vitro interaction of Candida tropicalis biofilm formed on catheter with human cells.}, journal = {Microbial pathogenesis}, volume = {125}, number = {}, pages = {177-182}, doi = {10.1016/j.micpath.2018.09.029}, pmid = {30227228}, issn = {1096-1208}, mesh = {Biofilms/*growth & development ; Candida tropicalis/*growth & development/physiology ; Catheters/*microbiology ; Endothelial Cells/microbiology ; Epithelial Cells/microbiology ; HeLa Cells ; *Host-Pathogen Interactions ; Human Umbilical Vein Endothelial Cells ; Humans ; Hyphae/growth & development ; }, abstract = {Candida tropicalis has emerged as one of the major Candida non-C. albicans species, in terms of epidemiology and virulence. Despite its virulence, C. tropicalis pathogenic mechanism has yet not been fully defined. The current study aimed to demonstrate the interaction of mature C. tropicalis ATCC 750 biofilm formed on catheter with different human cell lines. In vitro mature (72 h) C. tropicalis biofilms were produced on small catheter fragments (SCF) and were mainly composed by blastoconidia. Then, migration of yeast cells from mature biofilm to human cell surfaces (HeLa and HUVEC) was investigated. After contact with both cell lines, the surface of SCF, containing mature C. tropicalis biofilm, exhibited predominantly the filamentous form. Meanwhile, fresh biofilm formed on human cell surfaces also revealed mainly of blastoconidia involved by extracellular matrix. Total biomass and metabolic activity from the remaining biofilm on SCF surface, after direct contact with human cells, exhibited a significant reduction. Mature C. tropicalis biofilm modified its extracellular matrix components, after contact with human cells. Thus, we described for the first time an easy and simple in vitro model with catheter, which could be a powerful tool for future studies that desires to elucidate the mechanisms involved in C. tropicalis biofilm.}, } @article {pmid30226395, year = {2019}, author = {Chen, X and Yu, C and Li, S and Li, X and Liu, Q}, title = {Integration Host Factor Is Essential for Biofilm Formation, Extracellular Enzyme, Zeamine Production, and Virulence in Dickeya zeae.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {32}, number = {3}, pages = {325-335}, doi = {10.1094/MPMI-04-18-0096-R}, pmid = {30226395}, issn = {0894-0282}, mesh = {*Bacterial Proteins/genetics/metabolism ; *Biofilms ; China ; *Gammaproteobacteria/enzymology/pathogenicity/physiology ; Gene Knockout Techniques ; *Integration Host Factors/genetics/metabolism ; *Macrolides/metabolism ; Mutation ; *Polyamines/metabolism ; *Virulence/genetics ; }, abstract = {Dickeya zeae is a globally important pathogenic bacterium that infects many crops, including rice, maize, potato, and banana. Bacterial foot rot of rice caused by D. zeae is one of the most important bacterial diseases of rice in China and some Southeast Asian countries. To investigate the functions of integration host factor (IHF) in D. zeae, we generated knockout mutants of ihfA and ihfB. Phenotypic assays showed that both the ΔihfA and ΔihfB strains had greatly reduced mobility, biofilm formation, extracellular protease, and pectinase activities, and toxin production compared with the wild-type strain. In addition, the mutants did not inhibit the germination of rice seeds, failed to cause soft rot in potatoes and a hypersensitive response in tobacco, and were avirulent in rice. Quantitative reverse-transcription polymerase chain reaction analysis demonstrated that IHF positively regulates the expression of zmsA, hrpN/Y, pelA/B/C, pehX, celZ, prtG, fliC, and DGC (diguanylate cyclase). Electrophoretic mobility shift assays further confirmed that IhfA binds to the promoter region of the DGC gene and may alter the levels of a second bacterial messenger, c-di-GMP, to regulate the pathogenicity or other physiological functions of D. zeae. In summary, IHF is an important integrated regulator of pathogenicity in D. zeae.}, } @article {pmid30224941, year = {2018}, author = {Maharjan, G and Khadka, P and Siddhi Shilpakar, G and Chapagain, G and Dhungana, GR}, title = {Catheter-Associated Urinary Tract Infection and Obstinate Biofilm Producers.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2018}, number = {}, pages = {7624857}, pmid = {30224941}, issn = {1712-9532}, abstract = {BACKGROUND: Biofilms, or colonies of uropathogen growing on the surface of indwelling medical devices, can inflict obstinate or recurring infection, thought-provoking antimicrobial therapy.

METHODS: This prospective analysis included 105 urine samples from catheterized patients receiving intensive care. Ensuing phenotypic identification, antibiotic sensitivity test was performed by modified Kirby-Bauer disc diffusion method following CLSI guidelines; MDR isolates were identified according to the combined guidelines of the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC). Biofilm-forming uropathogens were detected by the tissue culture plate (TCA) method.

RESULTS: The predominant uropathogen in catheter-associated UTIs (CAUTIs) was Escherichia coli 57%, followed by Klebsiella pneumonia 15%, Pseudomonas aeruginosa 12%, Staphylococcus aureus 8%, Enterobacter spp. 3%, Enterococcus faecalis, Acinetobacter spp., and Proteus mirabilis 1.5%, of which 46% isolates were biofilm producers. Prime biofilm producers were Escherichia coli 33%, followed by Klebsiella pneumoniae 30%, Pseudomonas aeruginosa 20%, Staphylococcus aureus 10%, Acinetobacter, and Enterobacter 3.33%. Multidrug resistance associated with biofilm producers were greater than biofilm nonproducers. The Gram-negative biofilm producers found 96.15%, 80.76%, 73.07%, 53.84%, 53.84%, 46.15%, 19.23%, and 11.5% resistant to amoxyclave, ceftazidime, tetracycline, gentamicin, meropenem, nitrofurantoin, amikacin, imipenem, and fosfomycin, respectively. Gram-positive biofilm producers, however, were found 100% resistant to tetracycline, cloxacillin, and amoxyclave: 66.67% resistant to ampicillin while 33.33% resistant to gentamicin, ciprofloxacin, and nitrofurantoin.

CONCLUSION: High antimicrobial resistance was observed in biofilm producers than non-biofilm producers. Of recommended antimicrobial therapies for CAUTIs, ampicillin and amoxicillin-clavulanate were the least active antibiotics, whereas piperacillin/tazobactam and imipenem were found as the most effectual for gram-negative biofilm producer. Likewise, amoxicillin-clavulanate and tetracycline were the least active antibiotics, whereas vancomycin, fosfomycin, piperacillin-tazobactam, and meropenem were found as the most effective antibiotic for Gram-positive biofilm producer. In the limelight, the activity fosfomycin was commendable against both Gram-positive and Gram-negative biofilm producers.}, } @article {pmid30224574, year = {2019}, author = {Ramalingam, K and Lee, V}, title = {Biotic and abiotic substrates for enhancing Acinetobacter baumannii biofilm formation: New approach using extracellular matrix and slanted coverslip technique.}, journal = {The Journal of general and applied microbiology}, volume = {65}, number = {2}, pages = {64-71}, doi = {10.2323/jgam.2018.05.004}, pmid = {30224574}, issn = {1349-8037}, mesh = {Acinetobacter baumannii/genetics/*physiology/ultrastructure ; Bacterial Adhesion ; Bacterial Proteins/metabolism ; Bacteriological Techniques/instrumentation/*methods ; Biofilms/drug effects/*growth & development ; Extracellular Matrix/chemistry/*metabolism/ultrastructure ; Extracellular Matrix Proteins/pharmacology ; Fimbriae, Bacterial/metabolism ; }, abstract = {Acinetobacter baumannii has been well recognized as a problematic human pathogen and several reports has shown the incidence of multidrug and pandrug-resistant A. baumannii strains in infirmary infections. A. baumannii grows only on an air-liquid interface and does not form a contiguous biofilm. Extracellular matrices (ECM) and slanted glass coverslips are (SGC) used as biofilm substrates and biofilms have been investigated by SEM, confocal and crystal violet staining. ECM has shown enhanced biofilm formation under dynamic conditions rather than static conditions. SGC biofilm yield assay has shown higher levels of continuous layers and packed thicker biofilm formation with glass coverslip inserts, up to 1.7 to 3 times higher biofilm formation, than when compared with no glass coverslip inserts. A media immersed ECM study revealed that biofilm grown on extracellular matrixes formed thread-like pili structures, and that these structures had contact with the ECM and also showed excellent cell-to-cell interaction. In summary, A. baumannii showed higher biofilm formation capacities with ECM, while the prominent results were directly related with the biofilm formation capacity of A. baumannii. For the initial step of biofilm formation, adherence is an important factor and, consequently, strains with a comparatively high capability to adhere to extracellular matrices and slanted glass coverslips provide a new method of enhanced biofilm growth for in vitro assays. ECM can be used as a substrate for immersed biofilm formation studies and the SGC method for air-liquid interface exposed biofilm formation studies, and these substrates can provide better biofilm growth and easy handling for in vitro adherence and biofilm assays.}, } @article {pmid30224496, year = {2018}, author = {Mukherjee, S and Moustafa, DA and Stergioula, V and Smith, CD and Goldberg, JB and Bassler, BL}, title = {The PqsE and RhlR proteins are an autoinducer synthase-receptor pair that control virulence and biofilm development in Pseudomonas aeruginosa.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {40}, pages = {E9411-E9418}, pmid = {30224496}, issn = {1091-6490}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Pseudomonas aeruginosa/*pathogenicity/*physiology ; Quorum Sensing/*physiology ; Thiolester Hydrolases/genetics/*metabolism ; }, abstract = {Pseudomonas aeruginosa is a leading cause of life-threatening nosocomial infections. Many virulence factors produced by P. aeruginosa are controlled by the cell-to-cell communication process called quorum sensing (QS). QS depends on the synthesis, release, and groupwide response to extracellular signaling molecules called autoinducers. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, that produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Previously, we discovered that RhlR regulates both RhlI-dependent and RhlI-independent regulons, and we proposed that an alternative ligand functions together with RhlR to control the target genes in the absence of RhlI. Here, we report the identification of an enzyme, PqsE, which is the alternative-ligand synthase. Using biofilm analyses, reporter assays, site-directed mutagenesis, protein biochemistry, and animal infection studies, we show that the PqsE-produced alternative ligand is the key autoinducer that promotes virulence gene expression. Thus, PqsE can be targeted for therapeutic intervention. Furthermore, this work shows that PqsE and RhlR function as a QS-autoinducer synthase-receptor pair that drives group behaviors in P. aeruginosa.}, } @article {pmid30224144, year = {2018}, author = {Jiang, Z and Zhang, D and Zhou, L and Deng, D and Duan, M and Liu, Y}, title = {Enhanced catalytic capability of electroactive biofilm modified with different kinds of carbon nanotubes.}, journal = {Analytica chimica acta}, volume = {1035}, number = {}, pages = {51-59}, doi = {10.1016/j.aca.2018.06.077}, pmid = {30224144}, issn = {1873-4324}, mesh = {Biocatalysis ; Bioelectric Energy Sources ; Biofilms/*growth & development ; Culture Media ; Electrochemistry/instrumentation/*methods ; Electrodes ; Geobacter/chemistry/*physiology/ultrastructure ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Nanotubes, Carbon/*chemistry ; }, abstract = {In this study two methods including coating carbon nanotubes (CNTs) layers on the electrode surface and adding CNTs-suspension during electrochemically active biofilms (EABs) growth were used, respectively, to develop CNTs hybrid EABs for enhancing electricity generation capability of EABs. EABs growth on the CNTs with functional groups of hydroxyl (CNTs-OH) or carboxyl (CNTs-COOH) and pristine CNTs without functionalization (P-CNTs) modified electrode was investigated. The maximum current densities of EABs growth on the P-CNTs, CNTs-OH and CNTs-COOH coated electrode were respective 1300 ± 117, 1082 ± 54 and 1124 ± 78 μA cm[-2], which were much higher than unmodified electrode (663 μA cm[-2]). Meanwhile, EABs growth in doping CNTs-COOH or CNTs-OH suspensions system also produced twice higher current density than that on unmodified electrode. These results indicated that the current production of EABs can be significantly enhanced by coating P-CNTs, CNTs-OH, CNTs-COOH layers on the electrode surface or doping CNTs-OH and CNTs-COOH suspension into EABs. Furthermore, morphology analysis of as-obtained EABs had also been studied. It was found that there was no significant difference of the morphological characteristic for EABs growth on different types CNTs coated electrode surface. By comparison, a nano-hybrid porous structure of CNTs and EABs was observed when CNTs-COOH or CNTs-OH suspension was added into the medium during EABs growth, which will be responsible for high current generation.}, } @article {pmid30223164, year = {2018}, author = {Vaigankar, DC and Dubey, SK and Mujawar, SY and D'Costa, A and S K, S}, title = {Tellurite biotransformation and detoxification by Shewanella baltica with simultaneous synthesis of tellurium nanorods exhibiting photo-catalytic and anti-biofilm activity.}, journal = {Ecotoxicology and environmental safety}, volume = {165}, number = {}, pages = {516-526}, doi = {10.1016/j.ecoenv.2018.08.111}, pmid = {30223164}, issn = {1090-2414}, mesh = {*Biodegradation, Environmental ; Biofilms ; *Inactivation, Metabolic ; India ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Nanoparticles ; Nanotubes/*chemistry ; RNA, Ribosomal, 16S/metabolism ; Shewanella/classification/genetics/*metabolism ; Tellurium/*chemistry ; }, abstract = {Tellurite reducing bacterial strain was isolated from Zuari estuary, Goa India which could tolerate 5.5 mM potassium tellurite with a minimum inhibitory concentration of 6 mM. This strain was designated as GUSDZ9 and was identified as Shewanella baltica (accession number: MF350629) based on 16S rRNA gene sequencing and BLAST analysis. The Diethyl-dithiocarbamate based colorimetric analysis clearly demonstrated a complete reduction of 2 mM tellurite to elemental tellurium during the late stationary phase. Te Nanoparticles (TeNPs) biosynthesis which initiated at early log phase (i.e. 4 h) was evidently monitored through colour change and a peak due to surface plasmon resonance at 210 nm using UV-Vis spectroscopic analysis. X-ray crystallographic studies and transmission electron microscopy revealed unique nano-rods with a diameter ranging from 8 to 75 nm. Energy dispersive X-ray analysis further confirmed the presence of pure tellurium. The biogenic TeNPs at 10 and 5 µg/mL evidently demonstrated 90% degradation of methylene blue dye and anti-biofilm activity against potential Gram-positive and Gram-negative human pathogens respectively. The alkaline comet assay revealed time and dose-dependent genotoxicity at concentrations higher than 15 µg/mL of TeNPs. This study clearly demonstrated the potential of Shewanella baltica strain GUSDZ9 in bioremediation of toxic tellurite through bio-reduction into elemental tellurium and involvement of biogenic TeNPs in the photo-catalytic reduction of methylene blue and anti-biofilm activity. This is the first report of its kind on the synthesis of biogenic TeNPs from Shewanella baltica demonstrating photo-catalytic, anti-biofilm activity as well as genotoxicity.}, } @article {pmid30221799, year = {2018}, author = {Hongman, H and Yifang, W and Gongliang, Z and Yaolei, Z and Longquan, X and Hongshun, H and Yue, W and Meishan, L}, title = {Effects of Sulfide Flavors on AHL-Mediated Quorum Sensing and Biofilm Formation of Hafnia alvei.}, journal = {Journal of food science}, volume = {83}, number = {10}, pages = {2550-2559}, doi = {10.1111/1750-3841.14345}, pmid = {30221799}, issn = {1750-3841}, support = {2017YFC1600403//The National Key R& D Program of China/ ; 201602049//The Science and Technology Foundation of Liaoning Province/ ; }, mesh = {4-Butyrolactone/analogs & derivatives ; Allyl Compounds ; Biofilms/*growth & development ; China ; Chromobacterium/*drug effects ; Disulfides ; Flavoring Agents/*chemistry ; Food Analysis ; Hafnia alvei/*drug effects ; Quorum Sensing/*drug effects ; Sulfides/*analysis ; }, abstract = {UNLABELLED: In this study, 10 different sulfide flavor compounds commonly used as food additives were screened for antiquorum-sensing activity. Among these, diallyl disulfide (DADS) and methyl 2-methyl-3-furyl disulfide (MMFDS) were found to exert the strongest inhibition against violacein production in Chromobacterium violaceum 026, the tested biosensor strain. DADS and MMFDS also inhibited the growth of Hafnia alvei H4, yielding MIC values of 48 and 41.6 mM, respectively. In addition, DADS and MMFDS also inhibited the ability of H. alvei H4 to produce acyl-homoserine lactone as demonstrated by the reduced level of C6-HSL in the supernatant of DADS-treated culture. At concentrations corresponding to 1/4 MIC, DADS, and MMFDS inhibited the swarming ability of H. alvei H4 by 73.50% and 76.43%, respectively, while having virtually no effect on cell growth. The same concentrations of DADS and MMFDS also completely inhibited the formation of biofilm. These antiquorum sensing effects of DADS and MMFDS involved changes in the expression of the quorum-sensing genes luxI and luxR. Quantitative RT-PCR analysis showed that the mRNA levels of both genes were significantly reduced by DADS and MMDFS at concentrations below their MICs. However, further test using a mutant strain of H. alvei lacking luxR (ΔluxR) revealed significant reduction in luxI mRNA level upon treatment of the strain with DADS or MMDFS, but no change in luxR mRNA level occurred when a luxI-lacking mutant (ΔluxI) was treated with these compounds. The result therefore suggested that the antiquorum-sensing effect of DADS and MMFDS against H. alvei H4 might operate mainly through the inhibition of luxI expression in the cells.

PRACTICAL APPLICATION: The sulfide flavors compounds used in this paper are commonly used in food processing in China and are listed in the national standard of Chinese food additives GB2760-2014. The application of sulfide flavors in food processing can enhance aroma and prevent food spoilage.}, } @article {pmid30221325, year = {2018}, author = {Raskov, H and Kragh, KN and Bjarnsholt, T and Alamili, M and Gögenur, I}, title = {Bacterial biofilm formation inside colonic crypts may accelerate colorectal carcinogenesis.}, journal = {Clinical and translational medicine}, volume = {7}, number = {1}, pages = {30}, pmid = {30221325}, issn = {2001-1326}, abstract = {BACKGROUND: Research in the field of relation between microbes and colorectal carcinogenesis has gained increasing interest in past years. Recently, link between microbial biofilm and carcinogenesis in colon was demonstrated by several authors indicating that biofilm not only is a key player in carcinogenesis, but also may contribute to the understanding of side-specific colon cancer-right sided colon cancer versus left sided. In this article, we briefly highlight the major findings of the research of biofilm and carcinogenesis and demonstrate our findings of colonic cancer tissue and colonic polyp examined for biofilm.

CASE PRESENTATION: Colonic cancer tissue from a patient with a right-sided colon cancer, and an adenoma tubular polyp were examined for biofilm formation by flourescens in situ hybridization. In cancer tissue we found biofilm formation on the surface epithelium but surprisingly also deep into the crypts. No biofilms were found in tubular polyp tissue.

CONCLUSIONS: To our knowledge, this is the first-time biofilm formation deep into colonic crypts are demonstrated in a patient with right-sided colon cancer. This may indicate that bacterial biofilm may have a key role in carcinogenesis.}, } @article {pmid30221220, year = {2018}, author = {Roselló, J and Giménez, S and Ibáñez, MD and Blázquez, MA and Santamarina, MP}, title = {Bomba Rice Conservation with a Natural Biofilm.}, journal = {ACS omega}, volume = {3}, number = {3}, pages = {2518-2526}, pmid = {30221220}, issn = {2470-1343}, abstract = {The chemical composition of commercial Syzygium aromaticum, Cinnamomum verum, and Laurus nobilis essential oils as well as their antifungal activity against four pathogenic fungi isolated from Mediterranean rice grains has been investigated. Eighty nine compounds accounting for between 98.5 and 99.4% of the total essential oil were identified. The phenylpropanoids eugenol (89.37 ± 0.29%) and eugenol (56.34 ± 0.41%), followed by eugenol acetate (19.48 ± 0.13%) were, respectively, the main compounds in clove and cinnamon essential oils, whereas large amounts of the oxygenated monoterpenes 1,8-cineole (58.07 ± 0.83%) and α-terpinyl acetate (13.05 ± 0.44%) were found in bay leaf essential oil. Clove and cinnamon oils showed the best antifungal activity results against all tested fungi. Against Alternaria alternata, clove essential oil displayed the best antifungal effect, whereas against Curvularia hawaiiensis, cinnamon essential oil was more active. Both essential oils showed a similar antifungal effect towards Fusarium proliferatum and Fusarium oxysporum. In vitro studies in inoculated rice grains showed that clove and cinnamon totally inhibited pathogenic fungal development after 30 days of incubation. In vivo studies showed that eugenol used with a polysaccharide such as agar-agar formed a fine coat which wraps the inoculated rice grains, creating a natural biofilm and reducing the development of all pathogenic fungi (80-95%) for 30 days.}, } @article {pmid30221108, year = {2018}, author = {Aumeeruddy-Elalfi, Z and Ismaël, IS and Hosenally, M and Zengin, G and Mahomoodally, MF}, title = {Essential oils from tropical medicinal herbs and food plants inhibit biofilm formation in vitro and are non-cytotoxic to human cells.}, journal = {3 Biotech}, volume = {8}, number = {9}, pages = {395}, pmid = {30221108}, issn = {2190-572X}, abstract = {The biofilm inhibition and eradication potential of essential oils (EOs) extracted from six tropical medicinal herbs and food plants [Psiadia arguta (PA), Psiadia terebinthina (PT), Citrus grandis (CGp), Citrus hystrix (CH), Citrus reticulata (CR), and Cinnamomum zeylanicum (CZ)] were assessed. The mechanism of inhibition was studied via quenching of efflux pump. Cytotoxicity was evaluated using Artemia salina assay and cell lines [human cervix carcinoma (HeLa), human lung fibroblast (MRC-5), and murine melanoma (B16F10)]. EOs of CH, CR, PA, and PT were found to be prospective antibiofilm agents (IC50 of 0.29, 0.59, 0.22, and 0.11 mg/mL against Staphylococcus epidermidis; 0.39, 0.54, 0.09, and 0.13 mg/mL against Escherichia coli; and 0.54, 0.90, 0.44 and 0.51 mg/mL against Candida albicans for CH, CR, PA, and PT, respectively). The simultaneous actions of the EOs and efflux pump inhibitor impacted on the resistance of the biofilms. LC50 of the EOs ranged from 223 to 583 µg/mL against A. salina. The non-cytotoxic concentration of the EOs varied from 200 to 300 µg/mL (HeLa and MRC-5), and 150-200 µg/mL (B16F10). EOs from these tropical medicinal herbs and food plants are useful sources of new antimicrobials with low cytotoxicity which could open new horizons in the drug development process.}, } @article {pmid30220506, year = {2018}, author = {Astasov-Frauenhoffer, M and Glauser, S and Fischer, J and Schmidli, F and Waltimo, T and Rohr, N}, title = {Biofilm formation on restorative materials and resin composite cements.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {34}, number = {11}, pages = {1702-1709}, doi = {10.1016/j.dental.2018.08.300}, pmid = {30220506}, issn = {1879-0097}, mesh = {*Biofilms ; Ceramics ; Composite Resins/*chemistry ; Dental Materials/*chemistry ; Fusobacterium nucleatum ; Materials Testing ; Microscopy, Electron, Scanning ; Porphyromonas gingivalis ; Resin Cements ; Spectrometry, X-Ray Emission ; Streptococcus sanguis ; Surface Properties ; Wettability ; Zirconium/chemistry ; }, abstract = {OBJECTIVES: Monolithic zirconia, polymer-infiltrated ceramic and acrylate polymer cemented with resin composite cement have recently been identified as prosthetic treatment options for zirconia implants. The aim of the present study is to determine in vitro, to what extent bacteria adhere to these materials.

METHODS: Disks made of zirconia (Vita YZ [YZ]), polymer-infiltrated ceramic (Vita Enamic [VE]), acrylate polymer (Vita CAD-Temp [CT]), self-adhesive cement (RelyX Unicem 2 Automix [RUN]) and of two different adhesive cements (RelyX Ulimate [RUL] and Vita Adiva F-Cem [VAF]) were produced. The biofilm formation of three bacterial species (Streptococcus sanguinis, Fusobacterium nucleatum, Porphyromonas gingivalis) on each material was assessed over 72h using a flow chamber system. The biofilms were quantified by crystal violet staining (optical density 595nm) and visualized using SEM. The inorganic composition of the different materials was analyzed and the wettability of the specimens was measured.

RESULTS: For the restorative materials lowest biofilm formation was found on CT: OD 0.5±0.1, followed by VE: OD 0.8±0.1 and YZ: OD 1.4±0.3. The biofilm formation on resin composite cements was significantly lower on VAF: OD 0.6±0.1 than for RUL: OD 0.9±0.1 and RUN: OD 1.0±0.1. A high wettability of the specimens with saliva/serum mixture tended to result in a higher biofilm formation. Correlations were obtained between the organic/inorganic composition of the materials and the polar/dispersive part of the surface free energy.

SIGNIFICANCE: Three-species biofilm formation on restorative and cement materials strongly relies on the materials composition. If the restorative material CT and cement VAF also prevent excessive biofilm formation in a clinical situation should be further investigated.}, } @article {pmid30220065, year = {2018}, author = {Benedek, T and Szentgyörgyi, F and Szabó, I and Kriszt, B and Révész, F and Radó, J and Maróti, G and Táncsics, A}, title = {Aerobic and oxygen-limited enrichment of BTEX-degrading biofilm bacteria: dominance of Malikia versus Acidovorax species.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {32}, pages = {32178-32195}, pmid = {30220065}, issn = {1614-7499}, mesh = {Benzene/analysis/metabolism ; Benzene Derivatives/analysis/metabolism ; *Biodegradation, Environmental ; Biofilms ; Comamonadaceae/*metabolism ; Groundwater/chemistry ; Hydrocarbons/metabolism ; Hydrocarbons, Aromatic/*metabolism ; Oxygen ; Phylogeny ; Toluene/analysis/metabolism ; Xylenes/analysis/metabolism ; }, abstract = {Due to their high resistance against environmental challenges, bacterial biofilms are ubiquitous and are frequently associated with undesired phenomena in environmental industry (e. g. biofouling). However, because of the high phylogenetic and functional diversity, bacterial biofilms are important sources of biotechnologically relevant microorganisms, e.g. those showing bioremediation potential. In our previous work, the high phylogenetic and metabolic diversity of a clogging biofilm, developed in a simple aromatic hydrocarbon (BTEX)-contaminated groundwater well was uncovered. The determination of relationships between different groups of biofilm bacteria and certain metabolic traits has been omitted so far. Therefore, by setting up new biofilm-based enrichment microcosms, the research goal of the present study was to identify the aerobic/hypoxic BTEX-degrading and/or prolific biofilm-forming bacteria. The initial bacterial community composition as well as temporal dynamics due to the selective enrichment has been determined. The obtained results indicated that the concentration of dissolved oxygen may be a strong selective force on the evolution and final structure of microbial communities, developed in hydrocarbon-contaminated environments. Accordingly, members of the genus Malikia proved to be the most dominant community members of the aerobic BTEX-degrading enrichments. Acidovorax spp. dominated the oxygen-limited/hypoxic setup. During the study, a strain collection of 23 different bacterial species was obtained. Non-pathogenic members of this strain collection, with outstanding biodegradation (e.g. Pseudomonas, Variovorax isolates) and biofilm-forming potential (e.g. Rhizobium), may potentially be applied in the development of biofilm-based semipermeable reactive biobarriers.}, } @article {pmid30218931, year = {2018}, author = {Han, F and Ye, W and Wei, D and Xu, W and Du, B and Wei, Q}, title = {Simultaneous nitrification-denitrification and membrane fouling alleviation in a submerged biofilm membrane bioreactor with coupling of sponge and biodegradable PBS carrier.}, journal = {Bioresource technology}, volume = {270}, number = {}, pages = {156-165}, doi = {10.1016/j.biortech.2018.09.026}, pmid = {30218931}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors/microbiology ; Denitrification ; Nitrification ; Nitrogen/analysis ; Polymers/chemistry ; Succinic Acid/chemistry ; Wastewater/chemistry ; }, abstract = {Simultaneous nitrification-denitrification (SND) was achieved in submerged biofilm membrane bioreactor (SBF-MBR) treating low carbon/nitrogen (C/N) ratio wastewater. A novel bio-carrier coupling of sponge and biodegradable poly(butanediol succinate) (PBS) was applied as external carbon source and biofilm carrier. Result represented that NH4[+]-N and total nitrogen removal efficiencies were high of 99.1% and 94.3% in the SBF-MBR. Protein (PN) contents from SND-biofilm were reduced by 10.5% and 44.3% in TB-EPS and LB-EPS, while polysaccharides (PS) were reduced by 45.8% and 34.8%, respectively. 3D-EEM spectra indicated that protein-like, humic acid-like and fulvic acid-like substances were the main components in EPS and their peak intensities were reduced. Additionally, membrane fouling of SBF-MBR was improved after the achievement of biofilm. Microbial community analysis showed that Simplicispira, Thauera, Desulfovibrio, Dechlorobacter and Acinetobacter were dominant genus, which indicated co-existence of nitrifying bacteria, heterotrophic denitrifiers and aerobic denitrifiers in the SBF-MBR.}, } @article {pmid30218926, year = {2018}, author = {Zhang, X and Prévoteau, A and Louro, RO and Paquete, CM and Rabaey, K}, title = {Periodic polarization of electroactive biofilms increases current density and charge carriers concentration while modifying biofilm structure.}, journal = {Biosensors & bioelectronics}, volume = {121}, number = {}, pages = {183-191}, doi = {10.1016/j.bios.2018.08.045}, pmid = {30218926}, issn = {1873-4235}, mesh = {Bioelectric Energy Sources ; *Biofilms ; *Biosensing Techniques ; Electrodes/*microbiology ; *Electrophysiological Phenomena ; Geobacter/*physiology ; }, abstract = {Anodic electroactive biofilms (EABs) need to overcome low current densities for applications such as microbial fuel cells or biosensors. EABs can store charge in self-produced redox proteins when temporarily left in open circuit, and discharge them once the electrode is appropriately repolarized, thus behaving as pseudocapacitors. Here we investigated the effect of such periodic polarization on the intrinsic nature of the EABs during their entire growth (i.e. starting from inoculation and for 10 days) on glassy carbon electrodes. An optimal periodic polarization (half-period of 10 s) greatly increased the maximum steady-state current density delivered by the Geobacter-dominated EABs (up to 1.10 ± 0.02 mA cm[-2], n = 3 electrodes) when compared to continuously polarized EABs (0.41 ± 0.04 mA cm[-2]); and increased the amount of electric charges produced per hour by 69 ± 17% even taking into account the half-periods of open circuit. This enhancement was highly correlated with a substantial increase in charge carriers concentration (10.6 ± 0.5 mMe- vs. 2.9 ± 0.6 mMe-), allowing higher charge storage capacity and higher electron mobility across the EABs. Our results suggest that appropriate periodic polarizations may upregulate the expression of heme-containing redox proteins associated with the matrix, such as c-type cytochromes. The EABs grown under periodic polarization presented mushroom-like structures on their top layers, while EABs grown under continuous polarization were flat.}, } @article {pmid30218533, year = {2018}, author = {Keeney, K and Trmcic, A and Zhu, Z and Delaquis, P and Wang, S}, title = {Stress survival islet 1 contributes to serotype-specific differences in biofilm formation in Listeria monocytogenes.}, journal = {Letters in applied microbiology}, volume = {67}, number = {6}, pages = {530-536}, doi = {10.1111/lam.13072}, pmid = {30218533}, issn = {1472-765X}, mesh = {Bacterial Adhesion/*genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; *Food Handling ; *Food Safety ; Genome, Bacterial/genetics ; Genotype ; Listeria monocytogenes/*genetics/*isolation & purification ; Listeriosis/microbiology/prevention & control ; Serogroup ; }, abstract = {Listeria monocytogenes has a significant impact on the food industry by forming biofilms on food-processing equipment. Tandem analysis of whole-genome sequencing data with biofilm data from 166 environmental and food-related L. monocytogenes isolates has revealed serotypic and genetic factors that strongly correlate with adherence and biofilm formation, such as lineage, plasmid harbourage, a three-codon deletion in inlA and the presence of the stress survival islet 1 (SSI-1). Strains from serotype 1/2b, the majority of which contained SSI-1, formed the strongest biofilms, while serotype 4b strains, the majority of which did not contain SSI-1, formed the weakest biofilms. When serotype 1/2a was separated by its SSI-1 genotype, SSI-1-positive 1/2a strains demonstrated significantly higher capacity for biofilm formation after 3 days of growth at 30°C (P < 0·0001). Together, these findings indicate that SSI-1 may contribute to serotype-associated differences in the biofilm-forming capacity in L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: Parallel analysis of whole-genome sequences and serotype-specific data was performed to identify genetic markers that correlate with increased adherence and biofilm formation in L. monocytogenes. The analyses revealed the hitherto unrecognized role of SSI-1 in biofilm formation, contributing to deeper understanding of genetic factors that influence behaviour of the species in the food processing environment..}, } @article {pmid30218375, year = {2018}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Implementation of fed-batch strategies for vitamin K (menaquinone-7) production by Bacillus subtilis natto in biofilm reactors.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {21}, pages = {9147-9157}, doi = {10.1007/s00253-018-9340-7}, pmid = {30218375}, issn = {1432-0614}, support = {PEN04561-1002249//USDA National Institute of Food and Agriculture Federal Appropriations/ ; }, mesh = {Bacillus subtilis/*metabolism/ultrastructure ; Batch Cell Culture Techniques/*methods ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Carbon/metabolism ; Fermentation ; Glucose/metabolism ; Glycerol/metabolism ; Plastics ; Vitamin K/metabolism ; Vitamin K 2/*analogs & derivatives/analysis/metabolism ; }, abstract = {Recent studies show the essential health benefits associated with vitamin K, especially menaquinone-7 (MK-7). These benefits include reducing risks of cardiovascular diseases, osteoporosis, and even cancer. However, MK-7 production on an industrial level is only possible through bacterial fermentation and also current static fermentation strategies are not potent enough with difficulties to scale up. Biofilm reactors, however, may be a practical alternative. Biofilm reactors provide a controlled environment for the microorganisms to form mature and robust biofilms that enable them to produce value-added products with enhanced efficiencies. In this study, fed-batch addition of glucose and glycerol were investigated to the base media in biofilm reactors, as carbon source addition seemed crucial in batch fermentations. Results indicated that fed-batch strategies can be significantly effective in glucose-based medium, increasing the end-product concentrations to 28.7 ± 0.3 mg/L of MK-7 which was 2.3 fold higher than the level produced in suspended-cell bioreactors and renders the biofilm reactors as a potential replacement for static fermentation strategies. Moreover, morphological changes of B. subtilis were tracked during the 12-day long fermentation runs and finally, SEM investigations confirmed significant biofilm and extracellular matrices formed on the plastic composite support (PCS) in the biofilm reactors. In conclusion, biofilm reactors especially with fed-batch fermentation regimes seem to be an effective tool for MK-7 production at industrial scales.}, } @article {pmid30218278, year = {2018}, author = {Latif, M and May, EE}, title = {A Multiscale Agent-Based Model for the Investigation of E. coli K12 Metabolic Response During Biofilm Formation.}, journal = {Bulletin of mathematical biology}, volume = {80}, number = {11}, pages = {2917-2956}, doi = {10.1007/s11538-018-0494-3}, pmid = {30218278}, issn = {1522-9602}, mesh = {Biofilms/*growth & development ; Computer Simulation ; Escherichia coli K12/genetics/*metabolism/physiology ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Kinetics ; Mathematical Concepts ; Metabolic Networks and Pathways ; Metabolome ; *Models, Biological ; Phenotype ; Quorum Sensing ; Systems Biology ; }, abstract = {Bacterial biofilm formation is an organized collective response to biochemical cues that enables bacterial colonies to persist and withstand environmental insults. We developed a multiscale agent-based model that characterizes the intracellular, extracellular, and cellular scale interactions that modulate Escherichia coli MG1655 biofilm formation. Each bacterium's intracellular response and cellular state were represented as an outcome of interactions with the environment and neighboring bacteria. In the intracellular model, environment-driven gene expression and metabolism were captured using statistical regression and Michaelis-Menten kinetics, respectively. In the cellular model, growth, death, and type IV pili- and flagella-dependent movement were based on the bacteria's intracellular state. We implemented the extracellular model as a three-dimensional diffusion model used to describe glucose, oxygen, and autoinducer 2 gradients within the biofilm and bulk fluid. We validated the model by comparing simulation results to empirical quantitative biofilm profiles, gene expression, and metabolic concentrations. Using the model, we characterized and compared the temporal metabolic and gene expression profiles of sessile versus planktonic bacterial populations during biofilm formation and investigated correlations between gene expression and biofilm-associated metabolites and cellular scale phenotypes. Based on our in silico studies, planktonic bacteria had higher metabolite concentrations in the glycolysis and citric acid cycle pathways, with higher gene expression levels in flagella and lipopolysaccharide-associated genes. Conversely, sessile bacteria had higher metabolite concentrations in the autoinducer 2 pathway, with type IV pili, autoinducer 2 export, and cellular respiration genes upregulated in comparison with planktonic bacteria. Having demonstrated results consistent with in vitro static culture biofilm systems, our model enables examination of molecular phenomena within biofilms that are experimentally inaccessible and provides a framework for future exploration of how hypothesized molecular mechanisms impact bulk community behavior.}, } @article {pmid30217836, year = {2018}, author = {Xue, D and Tian, F and Yang, F and Chen, H and Yuan, X and Yang, CH and Chen, Y and Wang, Q and He, C}, title = {Phosphodiesterase EdpX1 Promotes Xanthomonas oryzae pv. oryzae Virulence, Exopolysaccharide Production, and Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {22}, pages = {}, pmid = {30217836}, issn = {1098-5336}, mesh = {Bacterial Proteins/chemistry/genetics/*metabolism ; *Biofilms ; Cyclic GMP/analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Mutation ; Oryza/*microbiology ; Phosphoric Diester Hydrolases/chemistry/genetics/*metabolism ; Plant Diseases/*microbiology ; Polysaccharides, Bacterial/*biosynthesis ; Protein Domains ; Signal Transduction ; Virulence ; Xanthomonas/*enzymology/genetics/*pathogenicity/physiology ; }, abstract = {In Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, there are over 20 genes encoding GGDEF, EAL, and HD-GYP domains, which are potentially involved in the metabolism of second messenger c-di-GMP. In this study, we focused on the characterization of an EAL domain protein, EdpX1. Deletion of the edpX1 gene resulted in a 2-fold increase in the intracellular c-di-GMP levels, which were restored to the wild-type levels in the complemented ΔedpX1(pB-edpX1) strain, demonstrating that EdpX1 is an active phosphodiesterase (PDE) in X. oryzae pv. oryzae. In addition, colorimetric assays further confirmed the PDE activity of EdpX1 by showing that the E153A mutation at the EAL motif strongly reduced its activity. Virulence assays on the leaves of susceptible rice showed that the ΔedpX1 mutant was severely impaired in causing disease symptoms. In trans expression of wild-type edpX1, but not edpX1[E153A], was able to complement the weakened virulence phenotype. These results indicated that an active EAL domain is required for EdpX1 to regulate the virulence of X. oryzae pv. oryzae. We then demonstrated that the ΔedpX1 mutant was defective in secreting exopolysaccharide (EPS) and forming biofilms. The expression of edpX1 in the ΔedpX1 mutant, but not edpX1[E153A], restored the defective phenotypes to near-wild-type levels. In addition, we observed that EdpX1-green fluorescent protein (EdpX1-GFP) exhibited multiple subcellular localization foci, and this pattern was dependent on its transmembrane (TM) region, which did not seem to directly contribute to the regulatory function of EdpX1. Thus, we concluded that EdpX1 exhibits PDE activity to control c-di-GMP levels, and its EAL domain is necessary and sufficient for its regulation of virulence in X. oryzae pv. oryzae.IMPORTANCE Bacteria utilize c-di-GMP as a second messenger to regulate various biological functions. The synthesis and degradation of c-di-GMP are catalyzed by GGDEF domains and an EAL or HD-GYP domain, respectively. Multiple genes encoding these domains are often found in one bacterial strain. For example, in the genome of X. oryzae pv. oryzae PXO99[A], 26 genes encoding proteins containing these domains were identified. Therefore, to fully appreciate the complexity and specificity of c-di-GMP signaling in X. oryzae pv. oryzae, the enzymatic activities and regulatory functions of each GGDEF, EAL, and HD-GYP domain protein need to be elucidated. In this study, we showed that the EAL domain protein EdpX1 is a major PDE to regulate diverse virulence phenotypes through the c-di-GMP signaling pathway.}, } @article {pmid30217006, year = {2018}, author = {Kamaruzzaman, NF and Tan, LP and Mat Yazid, KA and Saeed, SI and Hamdan, RH and Choong, SS and Wong, WK and Chivu, A and Gibson, AJ}, title = {Targeting the Bacterial Protective Armour; Challenges and Novel Strategies in the Treatment of Microbial Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {30217006}, issn = {1996-1944}, abstract = {Infectious disease caused by pathogenic bacteria continues to be the primary challenge to humanity. Antimicrobial resistance and microbial biofilm formation in part, lead to treatment failures. The formation of biofilms by nosocomial pathogens such as Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) on medical devices and on the surfaces of infected sites bring additional hurdles to existing therapies. In this review, we discuss the challenges encountered by conventional treatment strategies in the clinic. We also provide updates on current on-going research related to the development of novel anti-biofilm technologies. We intend for this review to provide understanding to readers on the current problem in health-care settings and propose new ideas for new intervention strategies to reduce the burden related to microbial infections.}, } @article {pmid30216921, year = {2018}, author = {Lan, M and Li, M and Liu, J and Quan, X and Li, Y and Li, B}, title = {Coal chemical reverse osmosis concentrate treatment by membrane-aerated biofilm reactor system.}, journal = {Bioresource technology}, volume = {270}, number = {}, pages = {120-128}, doi = {10.1016/j.biortech.2018.09.011}, pmid = {30216921}, issn = {1873-2976}, mesh = {*Biofilms ; *Coal ; Denitrification ; Nitrification ; Nitrogen/chemistry ; Osmosis ; Salinity ; Waste Disposal, Fluid ; }, abstract = {Coal chemical reverse osmosis concentrate (ROC), which is characterized by high salinity and high organics, remains as a serious environmental problem. In this study, a lab-scale three-stage membrane-aerated biofilm reactor (MABR) system was designed to treat such a ROC. The effects of influent salinity and operating parameters (pH, DO and HRT) on the treatment efficiency were discussed. The removal efficiencies of COD, NH4-N and TN under the optimal operating parameters reached to 81.01%, 92.31% and 70.72%, respectively. Simultaneous nitrification and denitrification (SND) as well as shortcut nitrogen removal were achieved. The salinity less than 3% did not induce significant decrease in treatment efficiency and microbial communities. Moreover, the dominant phyla in biofilms were Proteobacteria and Bacteroidetes. This work demonstrated MABR had great potential in ROC treatment.}, } @article {pmid30216370, year = {2018}, author = {Yu, Z and Deslouches, B and Walton, WG and Redinbo, MR and Di, YP}, title = {Enhanced biofilm prevention activity of a SPLUNC1-derived antimicrobial peptide against Staphylococcus aureus.}, journal = {PloS one}, volume = {13}, number = {9}, pages = {e0203621}, pmid = {30216370}, issn = {1932-6203}, support = {P30 ES010126/ES/NIEHS NIH HHS/United States ; R01 AI133351/AI/NIAID NIH HHS/United States ; R01 HL125128/HL/NHLBI NIH HHS/United States ; R01 CA207416/CA/NCI NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Glycoproteins/*chemistry ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Peptides/*chemistry/*pharmacology ; Phosphoproteins/*chemistry ; Staphylococcus aureus/*drug effects ; }, abstract = {SPLUNC1 is a multifunctional protein of the airway with antimicrobial properties. We previously reported that it displayed antibiofilm activities against P. aeruginosa. The goal of this study was to determine whether (1) the antibiofilm property is broad (including S. aureus, another prevalent organism in cystic fibrosis); (2) the α4 region is responsible for such activity; and (3), if so, this motif could be structurally optimized as an antimicrobial peptide with enhanced activities. We used S. aureus biofilm-prevention assays to determine bacterial biomass in the presence of SPLUNC1 and SPLUNC1Δα4 recombinant proteins, or SPLUNC1-derived peptides (α4 and α4M1), using the well-established crystal-violet biofilm detection assay. The SPLUNC1Δα4 showed markedly reduced biofilm prevention compared to the parent protein. Surprisingly, the 30-residue long α4 motif alone demonstrated minimal biofilm prevention activities. However, structural optimization of the α4 motif resulted in a modified peptide (α4M1) with significantly enhanced antibiofilm properties against methicillin-sensitive (MSSA) and-resistant (MRSA) S. aureus, including six different clinical strains of MRSA and the well-known USA300. Hemolytic activity was undetectable at up to 100μM for the peptides. The data warrant further investigation of α4-derived AMPs to explore the potential application of antimicrobial peptides to combat bacterial biofilm-related infections.}, } @article {pmid30215741, year = {2018}, author = {Cools, F and Torfs, E and Vanhoutte, B and de Macedo, MB and Bonofiglio, L and Mollerach, M and Maes, L and Caljon, G and Delputte, P and Cappoen, D and Cos, P}, title = {Streptococcus pneumoniae galU gene mutation has a direct effect on biofilm growth, adherence and phagocytosis in vitro and pathogenicity in vivo.}, journal = {Pathogens and disease}, volume = {76}, number = {7}, pages = {}, doi = {10.1093/femspd/fty069}, pmid = {30215741}, issn = {2049-632X}, mesh = {Animals ; *Bacterial Adhesion ; Bacterial Capsules/metabolism ; Biofilms/*growth & development ; Cell Line ; Disease Models, Animal ; Epithelial Cells/microbiology ; Humans ; Lepidoptera ; Macrophages/immunology/microbiology ; Mice ; Mutant Proteins/*genetics/metabolism ; *Mutation ; *Phagocytosis ; Pneumococcal Infections/microbiology/pathology ; Streptococcus pneumoniae/*enzymology/genetics/immunology/physiology ; UTP-Glucose-1-Phosphate Uridylyltransferase/*genetics/metabolism ; Virulence Factors/genetics/metabolism ; }, abstract = {Streptococcus pneumoniae, the most common cause of bacterial pneumonia, has developed a wide range of virulence factors to evade the immune system of which the polysaccharide capsule is the most important one. Formation of this capsule is dependent on the cps gene locus, but also involves other genes-like galU. The pyrophosphorylase encoded by galU plays a role in the UDP-glucose metabolism of prokaryotes and is required for the biosynthesis of capsular polysaccharides. In this paper, the effect of a galU mutation leading to a dysfunctional UDP-glucose pyrophosphorylase (UDPG:PP) on in vitro biofilm biomass, adherence to lung epithelial cells and macrophage phagocytosis is studied. Last, in vivo virulence using a Galleria mellonella model has been studied. We show that the mutation improves streptococcal adherence to epithelial cells and macrophage phagocytosis in vitro, while there is no definitive correlation on biofilm formation between parent and mutant strains. Moreover, in vivo virulence is attenuated for all mutated strains. Together, these results demonstrate that a galU mutation in S. pneumoniae influences host cell interactions in vitro and in vivo and can strongly influence the outcome of a streptococcal infection. As such, UDPG:PP is worth investigating further as a potential drug target.}, } @article {pmid30215136, year = {2018}, author = {Bisson, C and Lec, PH and Blique, M and Thilly, N and Machouart, M}, title = {Presence of trichomonads in subgingival biofilm of patients with periodontitis: preliminary results.}, journal = {Parasitology research}, volume = {117}, number = {12}, pages = {3767-3774}, pmid = {30215136}, issn = {1432-1955}, mesh = {Adult ; Biofilms/growth & development ; Dental Deposits/parasitology ; Female ; Gingiva/*parasitology ; Humans ; Male ; Microscopy, Phase-Contrast ; Middle Aged ; *Oral Hygiene ; *Oral Hygiene Index ; Periodontitis/*parasitology ; Tooth Mobility/parasitology ; Trichomonas/*isolation & purification ; }, abstract = {This study aims to evaluate the prevalence of trichomonads in the subgingival biofilm of patients with periodontitis. Secondarily, the trichomonad presence was related to patient characteristics and periodontal clinical parameters, in order to highlight the factor favoring the development of these protozoans. Subgingival biofilm samples were collected from at least two diseased and one healthy site in 50 patients suffering from periodontitis. Trichomonads were identified using phase contrast microscopy. All patient characteristics and periodontal clinical parameter data were then statistically analyzed. From the 50 patients examined, 195 sites were sampled, including 145 diseased ones. Trichomonads were only observed on 16 of the 145 diseased sites (11%) and none in the other 50 healthy sites. Based on these results, 20% (n = 10) of patients were positive for the presence of trichomonads from at least one of the diseased sites collected. Tooth mobility, substantial supra-gingival dental deposits, and severe clinical attachment loss were statistically associated with trichomonad presence. If the subgingival biofilm of male patients over the age of 50 seemed to be more frequently contaminated with trichomonads, this data was not statistically supported. This preliminary study indicates for the first time that in periodontitis-involved patients, trichomonads are observed in the subgingival biofilm collected from diseased sites with severe bone loss, but not from healthy teeth. Further investigations are needed to fully explore the role of this microorganism in the etiology of periodontal disease.}, } @article {pmid30214915, year = {2017}, author = {Wilson, C and Lukowicz, R and Merchant, S and Valquier-Flynn, H and Caballero, J and Sandoval, J and Okuom, M and Huber, C and Brooks, TD and Wilson, E and Clement, B and Wentworth, CD and Holmes, AE}, title = {Quantitative and Qualitative Assessment Methods for Biofilm Growth: A Mini-review.}, journal = {Research & reviews. Journal of engineering and technology}, volume = {6}, number = {4}, pages = {}, pmid = {30214915}, issn = {2319-9873}, support = {P20 GM103427/GM/NIGMS NIH HHS/United States ; }, abstract = {Biofilms are microbial communities attached to a surface and embedded in an extracellular polymeric substance which provides for the protection, stability and nutrients of the various bacterial species indwelling. These communities can build up in a variety of different environments from industrial equipment to medical devices resulting in damage, loss of productivity and disease. They also have great potential for economic and societal benefits as bioremediation agents and renewable energy sources. The great potential benefits and threats of biofilms has encouraged researchers across disciplines to study biofilm characteristics and antibiofilm strategies resulting in chemists, physicists, material scientists, and engineers, to develop beneficial biofilm applications and prevention methods. The ultimate outcome is a wealth of knowledge and innovative technology. However, without extensive formal training in microbes and biofilm research, these scientists find a daunting array of established techniques for growing, quantifying and characterizing biofilms while trying to design experiments and develop innovative laboratory protocols. This mini-review focuses on enriching interdisciplinary efforts and understanding by overviewing a variety of quantitative and qualitative biofilm characterization methods to assist the novice researcher in assay selection. This review consists of four parts. Part 1 is a brief overview of biofilms and the unique properties that demand a highly interdisciplinary approach. Part 2 describes the classical quantification techniques including colony forming unit (CFU) counting and crystal violet staining, but also introduces some modern methods including ATP bioluminescence and quartz crystal microbalance. Part 3 focuses on the characterization of biofilm morphology and chemistry including scanning electron microscopy and spectroscopic methods. Finally, Part 4 illustrates the use of software, including ImageJ and predictive modeling platforms, for biofilm analysis. Each section highlights the most common methods, including literature references, to help novice biofilm researchers make choices which commensurate with their study goals, budget and available equipment.}, } @article {pmid30214439, year = {2018}, author = {Santos, AL and Johnson, DB}, title = {Design and Application of a Low pH Upflow Biofilm Sulfidogenic Bioreactor for Recovering Transition Metals From Synthetic Waste Water at a Brazilian Copper Mine.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2051}, pmid = {30214439}, issn = {1664-302X}, abstract = {A sulfidogenic bioreactor, operated at low pH (4-5), was set up and used to remove transition metals (copper, nickel, cobalt, and zinc) from a synthetic mine water, based on the chemistry of a moderately acidic (pH 5) drainage stream at an operating copper mine in Brazil. The module was constructed as an upflow biofilm reactor, with microorganisms immobilized on porous glass beads, and was operated continuously for 462 days, during which time the 2 L bioreactor processed >2,000 L of synthetic mine water. The initial treatment involved removing copper (the most abundant metal present) off-line in a stream of H2S-containing gas generated by the bioreactor, which caused the synthetic mine water pH to fall to 2.1. The copper-free water was then amended with glycerol (the principal electron donor), yeast extract and basal salts, and pumped directly into the bioreactor where the other three transition metals were precipitated (also as sulfides), concurrent with increased solution pH. Although some acetate was generated, most of the glycerol fed to the bioreactor was oxidized to carbon dioxide, and was coupled to the reduction of sulfate to hydrogen sulfide. No archaea or eukaryotes were detected in the bioreactor microbial community, which was dominated by acidophilic sulfate-reducing Firmicutes (Peptococcaceae strain CEB3 and Desulfosporosinus acididurans); facultatively anaerobic non-sulfidogens (Acidithiobacillus ferrooxidans and Actinobacterium strain AR3) were also found in small relative abundance. This work demonstrated how a single low pH sulfidogenic bioreactor can be used to remediate a metal-rich mine water, and to facilitate the recovery (and therefore recycling) of target metals. The system was robust, and was operated empirically by means of pH control. Comparison of costs of the main consumables (glycerol and yeast extract) and the values of the metals recovered showed a major excess of the latter, supporting the view that sulfidogenic biotechnology can have significant economic as well as environmental advantages over current approaches used to remediate mine waters which produce secondary toxic wastes and fail to recover valuable metals.}, } @article {pmid30214437, year = {2018}, author = {Camarillo-Márquez, O and Córdova-Alcántara, IM and Hernández-Rodríguez, CH and García-Pérez, BE and Martínez-Rivera, MA and Rodríguez-Tovar, AV}, title = {Antagonistic Interaction of Staphylococcus aureus Toward Candida glabrata During in vitro Biofilm Formation Is Caused by an Apoptotic Mechanism.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2031}, pmid = {30214437}, issn = {1664-302X}, abstract = {Background: Infections caused by Candida species and Staphylococcus aureus are associated with biofilm formation. C. albicans-S. aureus interactions are synergistic due to the significant increase in mixed biofilms and improved resistance to vancomycin of S. aureus. C. glabrata and S. aureus both are nosocomial pathogens that cause opportunistic infections in similar host niches. However, there is scarce information concerning the interaction between these last microorganisms. Results: The relationship between C. glabrata and S. aureus was evaluated by estimating the viability of both microorganisms in co-culture of planktonic cells and in single and mixed biofilms. An antagonistic behavior of S. aureus and their cell-free bacterial supernatant (CFBS) toward C. glabrata, both in planktonic form and in biofilms, was demonstrated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and confocal laser scanning microscopy (CLSM) images showed yeast cells surrounded by bacteria, alterations in intracytoplasmic membranes, and non-viable blastoconidia with intact cell walls. Concomitantly, S. aureus cells remained viable and unaltered. The antagonistic activity of S. aureus toward C. glabrata was not due to cell-to-cell contact but the presence of CFBS, which causes a significant decrement in yeast viability and the formation of numerous lipid droplets (LDs), reactive oxygen species (ROS) accumulation, as well as nuclear alterations, and DNA fragmentation indicating the induction of an apoptotic mechanism. Conclusion: Our results demonstrate that the S. aureus CFBS causes cell death in C. glabrata by an apoptotic mechanism.}, } @article {pmid30214432, year = {2018}, author = {Guillonneau, R and Baraquet, C and Bazire, A and Molmeret, M}, title = {Multispecies Biofilm Development of Marine Bacteria Implies Complex Relationships Through Competition and Synergy and Modification of Matrix Components.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1960}, pmid = {30214432}, issn = {1664-302X}, abstract = {Microbial communities composition is largely shaped by interspecies competition or cooperation in most environments. Ecosystems are made of various dynamic microhabitats where microbial communities interact with each other establishing metabolically interdependent relationships. Very limited information is available on multispecies biofilms and their microhabitats related to natural environments. The objective of this study is to understand how marine bacteria isolated from biofilms in the Mediterranean Sea interact and compete with each other when cultivated in multispecies biofilms. Four strains (Persicivirga mediterranea TC4, Polaribacter sp. TC5, Shewanella sp. TC10 and TC11) with different phenotypical traits and abilities to form a biofilm have been selected from a previous study. Here, the results show that these strains displayed a different capacity to form a biofilm in static versus dynamic conditions where one strain, TC11, was highly susceptible to the flux. These bacteria appeared to be specialized in the secretion of one or two exopolymers. Only TC5 seemed to secrete inhibitory molecule(s) in its supernatant, with a significant effect on TC10. Most of the strains negatively impacted each other, except TC4 and TC10, which presented a synergetic effect in the two and three species biofilms. Interestingly, these two strains produced a newly secreted compound when grown in dual-species versus mono-species biofilms. TC5, which induced a strong inhibition on two of its partners in dual-species biofilms, outfitted the other bacteria in a four-species biofilm. Therefore, understanding how bacteria respond to interspecific interactions should help comprehending the dynamics of bacterial populations in their ecological niches.}, } @article {pmid30212901, year = {2019}, author = {Salinas, B and Guembe, M and Cussó, L and Kestler, M and Guinea, J and Desco, M and Muñoz, P and Bouza, E}, title = {Assessment of the anti-biofilm effect of micafungin in an animal model of catheter-related candidemia.}, journal = {Medical mycology}, volume = {57}, number = {4}, pages = {496-503}, doi = {10.1093/mmy/myy065}, pmid = {30212901}, issn = {1460-2709}, mesh = {Animal Structures/microbiology ; Animals ; Antifungal Agents/*administration & dosage/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candidemia/*drug therapy ; Catheter-Related Infections/*drug therapy ; Catheters/microbiology ; Disease Models, Animal ; Female ; Luminescent Measurements ; Micafungin/*administration & dosage/pharmacology ; Rats, Wistar ; Survival Analysis ; Treatment Outcome ; }, abstract = {In cases where catheter-related candidemia (CRC) must be managed without catheter withdrawal, antifungal lock therapy using highly active anti-biofilm (HAAB) agents is combined with systemic treatment. However, the activity of HAAB agents has never been studied in in vivo models using bioluminescence. We assessed the efficacy of micafungin using a bioluminescent Candida albicans SKCA23-ACTgLuc strain in an animal model of CRC. We divided 33 female Wistar rats into five groups: sham (A), infected nontreated (B), treated with lock therapy (0.16 mg/ml) (C), systemically treated only (1 mg/kg) (D), and systemically treated+lock (E). Catheters were colonized 24 h before insertion into the femoral vein (day 0). Treatment started on day 1 and lasted 7 days, followed by 7 days of surveillance. Bioluminescence assays were carried out on days 1, 3, 5, and 14, together with daily monitoring of clinical variables. Postmortem microbiological cultures from the catheter and several tissue samples were also obtained. Overall, 28 rats (84.8%) completed the study. Group B animals showed significant weight loss at days 2, 4, and 5 compared with groups C and D (P < .05). In group B, no animals survived after day 7, 75% had CRC, and bioluminescence remained constant 5 days after catheter implantation. Positive catheter culture rates in groups C, D, and E were, respectively, 83.3%, 62.5%, and 25.0% (P = .15). Micafungin proved to be a HAAB agent when administered both systemically and in lock therapy in an animal model of CRC, although the bioluminescence signal persists after treatment. This persistence should be further analyzed.}, } @article {pmid30212821, year = {2018}, author = {Zhang, JM and Liu, J and Wang, K and Zhang, X and Zhao, T and Luo, HM}, title = {Observations of Bacterial Biofilm on Ureteral Stent and Studies on the Distribution of Pathogenic Bacteria and Drug Resistance.}, journal = {Urologia internationalis}, volume = {101}, number = {3}, pages = {320-326}, doi = {10.1159/000490621}, pmid = {30212821}, issn = {1423-0399}, mesh = {Adult ; Aged ; *Bacteria ; *Biofilms ; Catheter-Related Infections/diagnosis/microbiology ; *Drug Resistance, Bacterial ; *Equipment Contamination ; Escherichia coli ; False Positive Reactions ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Middle Aged ; Pseudomonas aeruginosa ; Reproducibility of Results ; Stents/*adverse effects/*microbiology ; Ureter ; Urinary Tract Infections/microbiology ; Young Adult ; }, abstract = {OBJECTIVE: This study aims to observe the morphological characteristics of bacterial biofilm on the surface of ureteral stents and analyze distribution characteristics of pathogens on the bacterial biofilm and drug resistance.

METHODS: Ureteral stents were sampled from 129 patients. A scanning electron microscope was used to observe the morphological characteristics of bacterial biofilms, and the Congo red medium was applied to screen bacterial biofilm strains on the renal pelvis section, ureter section, and bladder section respectively. Urine culture was performed, and the drug sensitive test analysis was carried out for the pathogenic bacteria detected.

RESULTS: Bacterial biofilms can be observed on the surface of ureteral stents, and these bacteria are embraced by large amounts of fiber membranes. A total of 107 patients were found to be positive for biofilms with a positive rate of 82.9%. The positive rates of the bladder section, ureter section, renal pelvis section, and urine culture were 85.0, 42.9, 67.3, and 24.3% respectively. Pathogenic bacteria mainly concentrated on Escherichia coli, and the drug resistance rate of the bacterial biofilm strains on the ureteral stent was relatively higher.

CONCLUSION: The bacterial biofilm on the ureteral stent is an important factor that induces catheter-associated urinary tract infections.}, } @article {pmid30212777, year = {2018}, author = {Ye, Y and Huang, Y and Xia, A and Fu, Q and Liao, Q and Zeng, W and Zheng, Y and Zhu, X}, title = {Optimizing culture conditions for heterotrophic-assisted photoautotrophic biofilm growth of Chlorella vulgaris to simultaneously improve microalgae biomass and lipid productivity.}, journal = {Bioresource technology}, volume = {270}, number = {}, pages = {80-87}, doi = {10.1016/j.biortech.2018.08.116}, pmid = {30212777}, issn = {1873-2976}, mesh = {Autotrophic Processes ; Biofilms ; *Biomass ; Carbon/metabolism ; Carbon Cycle ; Chlorella vulgaris/*growth & development ; Glucose/biosynthesis ; Lipid Metabolism ; Lipids ; Microalgae/*growth & development ; Nitrogen/metabolism ; }, abstract = {In order to solve the technical bottleneck that the biomass yield and lipid accumulation cannot be increased simultaneously during microalgae growth, a heterotrophic-assisted photoautotrophic biofilm (HAPB) growth mode of Chlorella vulgaris was constructed. The light penetration capability of the microalgae biofilm formed through heterotrophic-assisted photoautotrophic growth was 64% stronger than that formed by photoautotrophic growth. Due to the different demands of autotrophic and heterotrophic growth of microalgae, the nutrient environment and growth conditions were optimized to fully utilize the advantages and potentials of the HAPB culture model. An optimized molar ratio of total inorganic carbon (CO2) to total organic carbon (glucose) (20:1) and a molar ratio of total carbon to total nitrogen (72:1) were obtained. The maximum specific growth rate of Chlorella vulgaris increased by 78% compared to that before optimization. Meanwhile, the lipid content and yield increased by 120% and 147%, respectively, up to 47.53% and 41.95 g m[-2].}, } @article {pmid30212776, year = {2018}, author = {Zhao, B and Ran, XC and Tian, M and An, Q and Guo, JS}, title = {Assessing the performance of a sequencing batch biofilm reactor bioaugmented with P. stutzeri strain XL-2 treating ammonium-rich wastewater.}, journal = {Bioresource technology}, volume = {270}, number = {}, pages = {70-79}, doi = {10.1016/j.biortech.2018.09.015}, pmid = {30212776}, issn = {1873-2976}, mesh = {Ammonium Compounds/*metabolism ; *Biofilms ; Denitrification ; Nitrification ; Nitrogen/analysis ; Pseudomonas stutzeri/*physiology ; Waste Disposal, Fluid/methods ; Wastewater ; }, abstract = {Pseudomonas stutzeri XL-2, with the capability of heterotrophic nitrification-aerobic denitrification and biofilm-forming, was applied in a sequencing batch biofilm reactor (SBBR) for bioaugmented treatment of ammonium-rich wastewater. The bioaugmented system SBBR 1 showed a rapid development of biofilm and relatively shorter time for biofilm hanging compared with the control system SBBR 2 without strain XL-2 inoculation. At different NH4[+]-N loads of 100, 200 and 300 mg/L, the effluent TN removal ratios ranged in 88.7-97.0%, 85.1-93.5% and 87.8-92.5% respectively in SBBR 1, while only ranged in 77.4-85.4%, 77.1-84.3% and 79.8-85.0% in SBBR 2. Less accumulation of NO2[-]-N and NO3[-]-N resulted in the better performance on TN removal in SBBR 1. Microbial community structure analysis revealed that strain XL-2 successfully proliferated in SBBR 1 and contributed to the less accumulation of NO2[-]-N and NO3[-]-N as well as biofilm formation.}, } @article {pmid30212684, year = {2018}, author = {Han, F and Wei, D and Ngo, HH and Guo, W and Xu, W and Du, B and Wei, Q}, title = {Performance, microbial community and fluorescent characteristic of microbial products in a solid-phase denitrification biofilm reactor for WWTP effluent treatment.}, journal = {Journal of environmental management}, volume = {227}, number = {}, pages = {375-385}, doi = {10.1016/j.jenvman.2018.09.002}, pmid = {30212684}, issn = {1095-8630}, mesh = {Bacteria ; *Biofilms ; *Bioreactors ; *Denitrification ; Nitrates ; Nitrogen ; }, abstract = {Microbial products, i.e. extracellular polymeric substance (EPS) and soluble microbial product (SMP), have a significant correlation with microbial activity of biologically based systems. In present study, the spectral characteristics of two kinds of microbial products were comprehensively evaluated in a solid-phase denitrification biofilm reactor for WWTP effluent treatment by using poly (butylene succinate) (PBS) as carbon source. After the achievement of PBS-biofilm, nitrate and total nitrogen removal efficiencies were high of 97.39 ± 1.24% and 96.38 ± 1.1%, respectively. The contents of protein and polysaccharide were changed different degrees in both LB-EPS and TB-EPS. Excitation-emission matrix (EEM) implied that protein-like substances played a significant role in the formation of PBS-biofilm. High-throughput sequencing result implied that the proportion of denitrifying bacteria, including Simplicispira, Dechloromonas, Diaphorobacter, Desulfovibrio, increased to 9.2%, 7.4%, 4.8% and 3.6% in PBS-biofilm system, respectively. According to EEM-PARAFAC, two components were identified from SMP samples, including protein-like substances for component 1 and humic-like and fulvic acid-like substances for component 2, respectively. Moreover, the fluorescent scores of two components expressed significant different trends to reaction time. Gas chromatography-mass spectrometer (GC-MS) implied that some new organic matters were produced in the effluent of SP-DBR due to biopolymer degradation and denitrification processes. The results could provide a new insight about the formation and stability of solid-phase denitrification PBS-biofilm via the point of microbial products.}, } @article {pmid30212364, year = {2018}, author = {Ead, JK and Snyder, RJ and Wise, J and Cuffy, C and Jafary, H and Fischborn, K}, title = {Is PASH Syndrome a Biofilm Disease?: A Case Series and Review of the Literature.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {30}, number = {8}, pages = {216-223}, pmid = {30212364}, issn = {1943-2704}, mesh = {Acne Vulgaris/*diagnosis/physiopathology/therapy ; Adult ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects/growth & development ; Debridement ; Female ; Hidradenitis Suppurativa/*diagnosis/physiopathology/therapy ; Humans ; Lower Extremity/*microbiology/pathology ; Patient Compliance/statistics & numerical data ; Pyoderma Gangrenosum/*diagnosis/physiopathology/therapy ; Syndrome ; Treatment Outcome ; }, abstract = {INTRODUCTION: When occurring together, pyoderma gangrenosum, severe acne, and hidradenitis suppurativa have been described as PASH syndrome. Due to the chronic autoinflammatory state existing in affected patients, PASH syndrome has been attributed to the dysregulation of wound healing.

CASE REPORTS: Two cases are presented that demonstrate the paradigmatic clinical features of PASH syndrome and its potential link as an expanding spectrum of bacterial biofilm disorder.

CONCLUSIONS: As reported herein, based on biofilm's clinical presentation and resistance to proper wound healing, it could serve as the common denominator and may redirect clinicians' treatment pathways in the near future.}, } @article {pmid30211421, year = {2018}, author = {Dai, X and Zhao, Y and Yu, Y and Chen, X and Wei, X and Zhang, X and Li, C}, title = {All-in-one NIR-activated nanoplatforms for enhanced bacterial biofilm eradication.}, journal = {Nanoscale}, volume = {10}, number = {39}, pages = {18520-18530}, doi = {10.1039/c8nr04748k}, pmid = {30211421}, issn = {2040-3372}, mesh = {Animals ; Biofilms/*drug effects ; Drug Resistance, Bacterial/*drug effects ; *Graphite/chemistry/pharmacology ; Humans ; Mice ; NIH 3T3 Cells ; Nanostructures/*chemistry ; Pseudomonas aeruginosa/*growth & development ; Staphylococcus aureus/*growth & development ; *Tobramycin/chemistry/pharmacology ; }, abstract = {The chronic infection of humans by antibiotic-resistant bacteria and their related biofilm have, so far, not been properly addressed. In the present work, we developed a novel antibacterial nanoplatform showing the most efficient antibiotic-resistant bacteria inhibition and biofilm eradication. This particular formulation contains tobramycin-conjugated graphene oxide, for efficiently capturing bacteria through electrostatic interactions and eliminating bacteria as a "nano-knife", and copper sulphide nanoparticles for enhancing the photothermal and photodynamic properties. This novel formulation can selectively eliminate bacteria over NIH 3T3 cells, and the biofilm eradication capacity was up to 70%. Importantly, the nanoplatforms can inhibit bacterial growth and promote the repair of antibiotic-resistant bacteria-infected wounds on rats without non-specific damage to normal tissue. This work provides an effective, simple, and rapid method for the design and fabrication of near-infrared light-induced nanoplatforms that offer possibilities to treat biofilm-related infections.}, } @article {pmid30210459, year = {2018}, author = {Yang, L and Zheng, C and Chen, Y and Ying, H}, title = {FLO Genes Family and Transcription Factor MIG1 Regulate Saccharomyces cerevisiae Biofilm Formation During Immobilized Fermentation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1860}, pmid = {30210459}, issn = {1664-302X}, abstract = {Saccharomyces cerevisiae immobilization is commonly used for efficient ethanol fuel production in industry due to the relatively higher ethanol stress resistance of S. cerevisiae in biofilms relative to planktonic cells. The mechanisms of biofilm formation and stress resistance, however, remain ambiguous. By analyzing biofilm and planktonic cell transcriptomes, this study observed that MIG1 (encoding a transcription factor) expression in cells increases during the biofilm formation process. To identify the role of MIG1 in yeast biofilm formation and the ethanol resistance of these cells, MIG1 was deleted and complemented in S. cerevisiae 1308. Results showed the MIG1 deletion mutant strain demonstrated weaker biofilm formation ability both on fibers and plastic than the wild-type and these could be restored by expressing MIG1 in deletion mutant. To verify the ability of MIG1 to regulate the expression of FLO genes, which encode adhesions responsible for yeast biofilm formation, FLO gene transcription levels were measured via qRT-PCR. Relative to wild-type S. cerevisiae, the adhesion genes FLO1, 5, and 9 which also demonstrate increased expression in the transcriptome of yeast cells during biofilm formation, but not FLO11, were down-regulated in the MIG1 mutant strain. Additionally, the MIG1 mutant lost a majority of its flocculation ability, which depended on cell-cell adhesions and its slightly invasive growth ability, dependent on cell-substrate adhesion. Deleting FLO1, 5, and 9 decreased biofilm formation on plastics, suggesting these FLO genes contribute to the biofilm formation process alongside FLO11. Moreover, the ethanol tolerance of yeast decreased in the MIG1 deletion mutant as well as the FLO11 deletion mutant, resulting in reduced biofilm formation during fermentation. It remains possible that in the later period of fermentation, when ethanol has accumulated, an over-expression of the FLO1, 5, and 9 genes regulated by MIG1 would enhanced cell-cell adhesions and thus protect cells in the outer layer of biofilms from ethanol, a function primarily dependent on cell-cell adhesions. This work offers a possible explanation for how biofilm formation is regulated during the immobilized fermentation process, and can enhance environmental tolerance in industrial production.}, } @article {pmid30209548, year = {2018}, author = {Wang, Y and Wang, Y and Sun, L and Grenier, D and Yi, L}, title = {Streptococcus suis biofilm: regulation, drug-resistance mechanisms, and disinfection strategies.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {21}, pages = {9121-9129}, doi = {10.1007/s00253-018-9356-z}, pmid = {30209548}, issn = {1432-0614}, support = {2018YFD0500100//the National Key Research and Development Program of China/ ; 31772761,31540095//the National Natural Science Foundation of China/ ; }, mesh = {Animals ; Biofilms/drug effects/*growth & development ; *Disinfection ; *Drug Resistance, Bacterial ; Humans ; Streptococcal Infections/*microbiology/prevention & control ; Streptococcus suis/drug effects/*growth & development/pathogenicity ; Swine ; Swine Diseases/*microbiology/prevention & control ; Virulence ; Zoonoses ; }, abstract = {Streptococcus suis (S. suis) is a major swine pathogen and an important zoonotic agent. Like most pathogens, the ability of S. suis to form biofilms plays a significant role in its virulence and drug resistance. A better understanding of the mechanisms involved in biofilm formation by S. suis as well as of the methods to efficiently remove and kill biofilm-embedded bacteria can be of high interest for the prevention and treatment of S. suis infections. The aim of this literature review is to update our current knowledge of S. suis biofilm formation, regulatory mechanisms, drug-resistance mechanisms, and disinfection strategies.}, } @article {pmid30208852, year = {2018}, author = {Khider, M and Willassen, NP and Hansen, H}, title = {The alternative sigma factor RpoQ regulates colony morphology, biofilm formation and motility in the fish pathogen Aliivibrio salmonicida.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {116}, pmid = {30208852}, issn = {1471-2180}, mesh = {Aliivibrio salmonicida/cytology/genetics/*growth & development/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; DNA-Directed RNA Polymerases/genetics/*metabolism ; Fish Diseases/*microbiology ; Fishes ; Gene Expression Regulation, Bacterial ; Sigma Factor/genetics/*metabolism ; }, abstract = {BACKGROUND: Quorum sensing (QS) is a cell-to cell communication system that bacteria use to synchronize activities as a group. LitR, the master regulator of QS in Aliivibrio salmonicida, was recently shown to regulate activities such as motility, rugosity and biofilm formation in a temperature dependent manner. LitR was also found to be a positive regulator of rpoQ. RpoQ is an alternative sigma factor belonging to the sigma -70 family. Alternative sigma factors direct gene transcription in response to environmental signals. In this work we have studied the role of RpoQ in biofilm formation, colony morphology and motility of A. salmonicida LFI1238.

RESULTS: The rpoQ gene in A. salmonicida LFI1238 was deleted using allelic exchange. We found that RpoQ is a strong repressor of rugose colony morphology and biofilm formation, and that it controls motility of the bacteria. We also show that overexpression of rpoQ in a ΔlitR mutant of A. salmonicida disrupts the biofilm produced by the ΔlitR mutant and decreases its motility, whereas rpoQ overexpression in the wild-type completely eliminates the motility.

CONCLUSION: The present work demonstrates that the RpoQ sigma factor is a novel regulatory component involved in modulating motility, colony morphology and biofilm formation in the fish pathogen A. salmonicida. The findings also confirm that RpoQ functions downstream of the QS master regulator LitR. However further studies are needed to elucidate how LitR and RpoQ work together in controlling phenotypes related to QS in A. salmonicida.}, } @article {pmid30208544, year = {2018}, author = {Zhang, X and Chen, T and Zhang, J and Zhang, H and Zheng, S and Chen, Z and Ma, Y}, title = {Performance of the nitrogen removal, bioactivity and microbial community responded to elevated norfloxacin antibiotic in an Anammox biofilm system.}, journal = {Chemosphere}, volume = {210}, number = {}, pages = {1185-1192}, doi = {10.1016/j.chemosphere.2018.07.100}, pmid = {30208544}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/*adverse effects ; Biofilms/*growth & development ; Nitrogen/*chemistry ; Norfloxacin/*adverse effects ; }, abstract = {Antibiotic pollution in nitrogen contained wastewater is an urgent issue. In this study, the nitrogen removal, biofilm property and microbial community of Anammox system were investigated with elevated norfloxacin (NOR) feeding. Batch experiments were carried out to detect the specific anammox activity (SAA) in each phase. Anammox system could resist NOR in 0.001-50 mg L[-1], in which the nitrogen removal was firstly limited to 0.220 from the initial 0.345 by NOR suppression and then regained to 0.354 kg m[-3] d[-1] after acclimatization. SAA decreased to 7.56 from the initial 10.84 and then climbed up to 11.01 mg g[-1] SS, while the relative abundance of Candidatus Kuenenia decreased to 11.33% and then picked up to 25.28% from the initial 20.74%. The suppression threshold on Anammox was calculated as 50-100 mg L[-1] NOR, the NRR, SAA and Candidatus Kuenenia abundance all recovered to almost the initial level when NOR feeding was terminated.}, } @article {pmid30207891, year = {2019}, author = {Morris, J and Kelly, N and Elliott, L and Grant, A and Wilkinson, M and Hazratwala, K and McEwen, P}, title = {Evaluation of Bacteriophage Anti-Biofilm Activity for Potential Control of Orthopedic Implant-Related Infections Caused by Staphylococcus aureus.}, journal = {Surgical infections}, volume = {20}, number = {1}, pages = {16-24}, doi = {10.1089/sur.2018.135}, pmid = {30207891}, issn = {1557-8674}, mesh = {Biofilms/*growth & development ; Humans ; *Microbial Viability ; Orthopedic Procedures/adverse effects ; Osteoarthritis/therapy ; Phage Therapy/methods ; Prosthesis-Related Infections/therapy ; Staphylococcal Infections/therapy ; Staphylococcus Phages/*growth & development ; Staphylococcus aureus/*physiology/virology ; }, abstract = {BACKGROUND: Despite significant advancements in surgical protocols and biomaterials for orthopedics, peri-prosthetic joint infection (PJI) remains a leading cause of implant failure. Staphylococcus aureus nasal colonization is an established risk factor for PJI, with methicillin-sensitive S. aureus a leading cause of orthopedic implant-related infections. The purpose of these in vitro studies was to investigate the antibacterial activity of a tailored bacteriophage cocktail against planktonic and biofilm-associated S. aureus.

METHODS: The S. aureus strains (n = 30) were screened for their susceptibility to a library of S. aureus-specific bacteriophage (n = 31). Five bacteriophage preparations that demonstrated bactericidal activity against >90% of S. aureus strains tested were combined as a StaPhage cocktail and assessed for their antibacterial activity toward planktonic and biofilm-associated S. aureus, with biofilms established on three-dimensional-printed porous titanium scaffolds.

RESULTS: StaPhage treatment immediately after bacterial inoculation inhibited growth of S. aureus by >98% in eight hour cultures when multiplicity of infection of phages to bacteria was greater than 1:1 (p < 0.01). Viable bacterial numbers within biofilms on titanium surfaces were significantly reduced (6.8 log10 to 6.2 log10 colony forming units [CFU]; p < 0.01) after exposure to the StaPhage cocktail, in vitro. No significant reduction was observed in biofilms exposed to 100 times the minimal inhibitory concentration of cefazolin (log10 6.81 CFU).

CONCLUSIONS: Combined, these data demonstrate the in vitro efficacy of S. aureus-specific bacteriophage cocktails against S. aureus growing on porous titanium and warrant further in vivo studies in a clinically relevant animal model to evaluate the potential application of bacteriophage in the management of PJI caused by S. aureus.}, } @article {pmid30207213, year = {2019}, author = {Guła, G and Dorotkiewicz-Jach, A and Korzekwa, K and Valvano, MA and Drulis-Kawa, Z}, title = {Complex Signaling Networks Controlling Dynamic Molecular Changes in Pseudomonas aeruginosa Biofilm.}, journal = {Current medicinal chemistry}, volume = {26}, number = {11}, pages = {1979-1993}, doi = {10.2174/0929867325666180912110151}, pmid = {30207213}, issn = {1875-533X}, mesh = {*Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Pseudomonas aeruginosa/growth & development/*physiology ; Quorum Sensing/*physiology ; Signal Transduction/*physiology ; }, abstract = {The environment exerts strong influence on microbes. Adaptation of microbes to changing conditions is a dynamic process regulated by complex networks. Pseudomonas aeruginosa is a life-threating, versatile opportunistic and multi drug resistant pathogen that provides a model to investigate adaptation mechanisms to environmental changes. The ability of P. aeruginosa to form biofilms and to modify virulence in response to environmental changes is coordinated by various mechanisms including two-component systems (TCS), and secondary messengers involved in quorum sensing (QS) and c-di-GMP networks (diguanylate cyclase systems, DGC). In this review, we focus on the role of c-di-GMP during biofilm formation. We describe TCS and QS signal cascades regulated by c-di-GMP in response to changes in the external environment. We present a complex signaling network dynamically changing during the transition of P. aeruginosa from the free-living to sessile mode of growth.}, } @article {pmid30205468, year = {2018}, author = {Silva, AF and Borges, A and Freitas, CF and Hioka, N and Mikcha, JMG and Simões, M}, title = {Antimicrobial Photodynamic Inactivation Mediated by Rose Bengal and Erythrosine Is Effective in the Control of Food-Related Bacteria in Planktonic and Biofilm States.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {9}, pages = {}, pmid = {30205468}, issn = {1420-3049}, support = {POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; }, mesh = {Bacteria/*drug effects ; Biofilms/*drug effects ; Cell Membrane/drug effects/metabolism ; Disinfectants/*pharmacology ; Disinfection/*methods ; Dose-Response Relationship, Radiation ; Erythrosine/*pharmacology ; *Food Microbiology ; Foodborne Diseases/prevention & control ; Light ; Photosensitizing Agents/*pharmacology ; Potassium/metabolism ; Rose Bengal/*pharmacology ; }, abstract = {The thermal and chemical-based methods applied for microbial control in the food industry are not always environmentally friendly and may change the nutritional and organoleptic characteristics of the final products. Moreover, the efficacy of sanitizing agents may be reduced when microbial cells are enclosed in biofilms. The objective of this study was to investigate the effect of photodynamic inactivation, using two xanthene dyes (rose bengal and erythrosine) as photosensitizing agents and green LED as a light source, against Staphylococcus aureus, Listeria innocua, Enterococcus hirae and Escherichia coli in both planktonic and biofilm states. Both photosensitizing agents were able to control planktonic cells of all bacteria tested. The treatments altered the physicochemical properties of cells surface and also induced potassium leakage, indicating damage of cell membranes. Although higher concentrations of the photosensitizing agents (ranging from 0.01 to 50.0 μmol/L) were needed to be applied, the culturability of biofilm cells was reduced to undetectable levels. This finding was confirmed by the live/dead staining, where propidium iodide-labeled bacteria numbers reached up to 100%. The overall results demonstrated that photoinactivation by rose bengal and erythrosine may be a powerful candidate for the control of planktonic cells and biofilms in the food sector.}, } @article {pmid30204411, year = {2018}, author = {Perez-Soto, N and Creese, O and Fernandez-Trillo, F and Krachler, AM}, title = {Aggregation of Vibrio cholerae by Cationic Polymers Enhances Quorum Sensing but Overrides Biofilm Dissipation in Response to Autoinduction.}, journal = {ACS chemical biology}, volume = {13}, number = {10}, pages = {3021-3029}, pmid = {30204411}, issn = {1554-8937}, support = {//Wellcome Trust/United Kingdom ; 177ISSFPP//Wellcome Trust/United Kingdom ; BB/M021513/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L007916/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M01116X/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Homoserine/analogs & derivatives/metabolism ; Ketones/metabolism ; Lactones/metabolism ; Phenotype ; Polymethacrylic Acids/chemistry/*pharmacology ; Propylamines/chemistry/*pharmacology ; Quorum Sensing/*drug effects ; Static Electricity ; Vibrio cholerae/chemistry/*drug effects/physiology ; Virulence/drug effects ; }, abstract = {Vibrio cholerae is a Gram-negative bacterium found in aquatic environments and a human pathogen of global significance. Its transition between host-associated and environmental lifestyles involves the tight regulation of niche-specific phenotypes such as motility, biofilm formation, and virulence. V. cholerae's transition from the host to environmental dispersal usually involves suppression of virulence and dispersion of biofilm communities. In contrast to this naturally occurring transition, bacterial aggregation by cationic polymers triggers a unique response, which is to suppress virulence gene expression while also triggering biofilm formation by V. cholerae, an artificial combination of traits that is potentially very useful to bind and neutralize the pathogen from contaminated water. Here, we set out to uncover the mechanistic basis of this polymer-triggered bacterial behavior. We found that bacteria-polymer aggregates undergo rapid autoinduction and achieve quorum sensing at bacterial densities far below those required for autoinduction in the absence of polymers. We demonstrate this induction of quorum sensing is due both to a rapid formation of autoinducer gradients and local enhancement of autoinducer concentrations within bacterial clusters as well as the stimulation of CAI-1 and AI-2 production by aggregated bacteria. We further found that polymers cause an induction of the biofilm-specific regulator VpsR and the biofilm structural protein RbmA, bypassing the usual suppression of biofilm during autoinduction. Overall, this study highlights that synthetic materials can be used to cross-wire natural bacterial responses to achieve a combination of phenotypes with potentially useful applications.}, } @article {pmid30204158, year = {2018}, author = {Kwon, HY and Kim, JY and Lee, JY and Yam, JKH and Hultqvist, LD and Xu, W and Rybtke, M and Tolker-Nielsen, T and Kim, JJ and Kang, NY and Yang, L and Park, SJ and Givskov, M and Chang, YT}, title = {CDy14: a novel biofilm probe targeting exopolysaccharide Psl.}, journal = {Chemical communications (Cambridge, England)}, volume = {54}, number = {84}, pages = {11865-11868}, doi = {10.1039/c8cc05544k}, pmid = {30204158}, issn = {1364-548X}, mesh = {*Biofilms ; Boron Compounds/*chemistry ; Fluorescent Dyes/chemistry/*metabolism ; Heterocyclic Compounds, 3-Ring/*chemistry ; Microscopy, Fluorescence ; Polysaccharides, Bacterial/chemistry/*metabolism ; Pseudomonas aeruginosa/chemistry ; }, abstract = {Detection of biofilm bacteria would be an ideal method for the physicians to diagnose chronic bacterial infections directly, but there are few imaging probes available so far. Here, we report the development of a novel biofilm detecting fluorescent probe, CDy14, through an unbiased screening of a fluorescence library and elucidated its binding partner Psl, an exopolysaccharide of the biofilm.}, } @article {pmid30203144, year = {2018}, author = {Sabba, F and Terada, A and Wells, G and Smets, BF and Nerenberg, R}, title = {Nitrous oxide emissions from biofilm processes for wastewater treatment.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {22}, pages = {9815-9829}, doi = {10.1007/s00253-018-9332-7}, pmid = {30203144}, issn = {1432-0614}, support = {U2R10//Water Environment Research Foundation/ ; CBET0954918//National Science Foundation/ ; 17H01893//Japan Society for the Promotion of Science/ ; 1335-00100B//Teknologi og Produktion, Det Frie Forskningsråd/ ; }, mesh = {Ammonia/metabolism ; Archaea/classification/genetics/isolation & purification/*metabolism ; Bacteria/classification/genetics/isolation & purification/*metabolism ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Heterotrophic Processes ; Nitrification ; Nitrites/metabolism ; Nitrous Oxide/*analysis/metabolism ; Oxygen/analysis/metabolism ; Wastewater/analysis/*microbiology ; }, abstract = {This paper discusses the microbial basis and the latest research on nitrous oxide (N2O) emissions from biofilms processes for wastewater treatment. Conditions that generally promote N2O formation in biofilms include (1) low DO values, or spatial DO transitions from high to low within the biofilm; (2) DO fluctuations within biofilm due to varying bulk DO concentrations or varying substrate concentrations; (3) conditions with high reaction rates, which lead to greater formation of intermediates, e.g., hydroxylamine (NH2OH) and nitrite (NO2[-]), that promote N2O formation; and (4) electron donor limitation for denitrification. Formation of N2O directly results from the activities of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and heterotrophic denitrifying bacteria. More research is needed on the roles of AOA, comammox, and specialized denitrifying microorganisms. In nitrifying biofilms, higher bulk ammonia (NH3) concentrations, higher nitrite (NO2[-]) concentrations, lower dissolved oxygen (DO), and greater biofilm thicknesses result in higher N2O emissions. In denitrifying biofilms, N2O accumulates at low levels as an intermediate and at higher levels at the oxic/anoxic transition regions of the biofilms and where COD becomes limiting. N2O formed in the outer regions can be consumed in the inner regions if COD penetrates sufficiently. In membrane-aerated biofilms, where nitrification takes place in the inner, aerobic biofilm region, the exterior anoxic biofilm can serve as a N2O sink. Reactors that include variable aeration or air scouring, such as denitrifying filters, trickling filters, or rotating biological contactors (RBCs), can form peaks of N2O emissions during or following a scouring or aeration event. N2O emissions from biofilm processes depend on the microbial composition, biofilm thickness, substrate concentrations and variability, and reactor type and operation. Given the complexity and difficulty in quantifying many of these factors, it may be difficult to accurately predict emissions for full-scale treatment plants. However, a better understanding of the mechanisms and the impacts of process configurations can help minimize N2O emission from biofilm processes for wastewater treatment.}, } @article {pmid30202852, year = {2019}, author = {Díaz-García, J and Marcos-Zambrano, LJ and Muñoz, P and Guinea, J and Escribano, P}, title = {Does the composition of polystyrene trays affect Candida spp. biofilm formation?.}, journal = {Medical mycology}, volume = {57}, number = {4}, pages = {504-509}, doi = {10.1093/mmy/myy064}, pmid = {30202852}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Candida/*growth & development/metabolism ; Candidemia/microbiology ; Humans ; Microbiological Techniques/*methods ; Polystyrenes/*chemistry ; }, abstract = {The biofilm formation ability of Candida species seems to have a role in the prognosis of patients with candidemia. Biofilm formation is usually tested using 96 well flat bottom polystyrene microtiter plates, although the type of plastic used is not commonly reported. This study compares biofilm formation by Candida spp. on six types of plates from three brands (three non-tissue-treated and three tissue-treated). Thirty isolates of each of the following species were selected: C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, as well as 15 isolates of C. krusei (n = 135 isolates) from patients with candidemia. Biofilm production was evaluated by measuring biomass production and metabolic activity. Our results show higher biomass production and metabolic activity of biofilms formed on non-tissue-treated plates in comparison to those formed on tissue-treated plates (P < .001). We only found significant differences in metabolic activity of biofilms formed on non-tissue-treated plates (P < .003). All comparisons including biofilm formation and metabolic activity among plates of the same brand yielded higher biofilm formation on non-treated plates compared to treated plates (P < .001). Significant difference in biomass production by C. parapsilosis was only seen when comparing between the various tissue-treated plastics (P < .03). In contrast, comparisons of different non-tissue-treated tray brands yielded significant metabolic activity differences for all species except for C. parapsilosis (P < .05). Biofilm formation and metabolic activity is significantly affected by the plastic composition of non-tissue-treated trays leading to increased biofilm formation.}, } @article {pmid30201944, year = {2018}, author = {Subhadra, B and Kim, DH and Woo, K and Surendran, S and Choi, CH}, title = {Control of Biofilm Formation in Healthcare: Recent Advances Exploiting Quorum-Sensing Interference Strategies and Multidrug Efflux Pump Inhibitors.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {30201944}, issn = {1996-1944}, support = {2017//Chungnam National University/ ; NRF-2014R1A61029617//National Research Foundation of Korea/ ; }, abstract = {Biofilm formation in healthcare is an issue of considerable concern, as it results in increased morbidity and mortality, imposing a significant financial burden on the healthcare system. Biofilms are highly resistant to conventional antimicrobial therapies and lead to persistent infections. Hence, there is a high demand for novel strategies other than conventional antibiotic therapies to control biofilm-based infections. There are two approaches which have been employed so far to control biofilm formation in healthcare settings: one is the development of biofilm inhibitors based on the understanding of the molecular mechanism of biofilm formation, and the other is to modify the biomaterials which are used in medical devices to prevent biofilm formation. This review will focus on the recent advances in anti-biofilm approaches by interrupting the quorum-sensing cellular communication system and the multidrug efflux pumps which play an important role in biofilm formation. Research efforts directed towards these promising strategies could eventually lead to the development of better anti-biofilm therapies than the conventional treatments.}, } @article {pmid30201526, year = {2019}, author = {Zhang, H and Du, R and Cao, S and Wang, S and Peng, Y}, title = {Mechanisms and characteristics of biofilm formation via novel DEAMOX system based on sequencing biofilm batch reactor.}, journal = {Journal of bioscience and bioengineering}, volume = {127}, number = {2}, pages = {206-212}, doi = {10.1016/j.jbiosc.2018.07.026}, pmid = {30201526}, issn = {1347-4421}, mesh = {Ammonia/metabolism ; Ammonium Compounds/*metabolism ; Bacteria/metabolism ; Bacterial Physiological Phenomena ; Batch Cell Culture Techniques/instrumentation/methods ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Denitrification/*physiology ; Nitrates/isolation & purification/metabolism ; Nitrogen/analysis ; Oxidation-Reduction ; Sewage/microbiology ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater/microbiology ; }, abstract = {A denitrifying ammonium oxidation (DEAMOX) process has been regarded as an innovative process to simultaneously treat ammonia and nitrate containing wastewaters, whereas very limited research has focused on its application in biofilm system. In this research, a novel DEAMOX process was established with fixed sponge carriers in a sequencing biofilm batch reactor (SBBR). To investigate biofilm formation process and characteristics can encourage further research on DEAMOX system optimization, deteriorated performance recovery strategies and application with actual wastewater. Total nitrogen removal efficiency was maintained at 93.0 % after 240 days of operation. With biofilm growth, the protein-like extracellular polymeric substances (EPS) and tightly-bound EPS (TB-EPS) of biofilms increased from 65.6 to 46.1, to 179.6 and 142.0 mg gVSS[-1], respectively, revealing that protein-like substances and TB-EPS promote biofilm formation. The mechanism of biofilm formation was discussed by analyzing the morphological development and functional bacterial activities of biofilms. Furthermore, high anammox activity was obtained in biofilms with specific NH4[+]N removal rates over 4.29 mgN gVSS[-1]h[-1], which were significantly higher than in suspended sludge (2.56 mgN gVSS[-1]h[-1]). Quantitative polymerase chain reaction results showed that the abundance of anammox bacteria in biofilms increased from 1.87 % to 11.48 % with biofilm growth. These results imply that mature biofilms formed on carriers and the anammox bacteria were sufficient enriched in DEAMOX-SBBR system.}, } @article {pmid30200829, year = {2019}, author = {Morohoshi, T and Xie, X and Ikeda, T}, title = {N-Acylhomoserine lactone-mediated quorum sensing regulates biofilm structure in Methylobacterium populi P-1M, an isolate from a pink-pigmented household biofilm.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {83}, number = {1}, pages = {174-180}, doi = {10.1080/09168451.2018.1518701}, pmid = {30200829}, issn = {1347-6947}, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Biofilms/*growth & development ; *Housing ; Methylobacterium/*cytology/genetics/metabolism/*physiology ; Mutation ; *Pigmentation ; *Quorum Sensing ; }, abstract = {Numerous gram-negative bacteria have quorum-sensing systems and produce AHL as a quorum-sensing signal molecule. In this study, we demonstrated that Methylobacterium populi P-1M, an isolate from a pink-pigmented household biofilm, produced two AHLs, C14:1-HSL as a predominant product and 3OHC14-HSL as a minor product. The complete genome sequence of M. populi P-1M revealed the presence of genes that are predicted to encode an AHL synthase (mpoI) and AHL receptor (mpoR). M. populi P-1M formed a pellicle-like biofilm, which had a flat surface and was easily removable. In contrast, biofilms formed by mpoI and/or mpoR deletion mutants had a wavy surface structure and strongly adhered to the glass tube. When C14:1-HSL was added to the mpoI mutant culture, the biofilm structure resembled that of the wild-type strain. These results demonstrated that the structure and adhesion strength of M. populi P-1M biofilms are determined in part by AHL-mediated quorum sensing.Abbreviations: AHL: N-acyl-l-homoserine lactone; C14:1-HSL: N-tetradecenoyl-l-homoserine lactone; 3OHC14-HSL: N-(3-hydroxytetradecanoyl)-l-homoserine lactone; SAM: S-adenosyl-l-methionine; ACP: acyl-acyl carrier protein; EPS: extracellular polysaccharide; DMSO: dimethyl sulfoxide.}, } @article {pmid30200616, year = {2018}, author = {Zhou, G and Wang, YS and Peng, H and Huang, XM and Xie, XB and Shi, QS}, title = {Role of Ttca of Citrobacter Werkmanii in Bacterial Growth, Biocides Resistance, Biofilm Formation and Swimming Motility.}, journal = {International journal of molecular sciences}, volume = {19}, number = {9}, pages = {}, pmid = {30200616}, issn = {1422-0067}, support = {2015A030313713//Natural Science Foundation of Guangdong Province/ ; 31500036 and 31770091//National Natural Science Foundation of China/ ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; Citrobacter/drug effects/*physiology ; Disinfectants/*pharmacology ; Drug Resistance, Bacterial ; Gene Library ; Mutagenesis ; Phylogeny ; Sulfurtransferases/*genetics ; Thiazoles/pharmacology ; }, abstract = {To screen, identify and study the genes involved in isothiazolone resistance and biofilm formation in Citrobacter werkmanii strain BF-6. A Tn5 transposon library of approximately 900 mutants of C. werkmanii strain BF-6 was generated and screened to isolate 1,2-benzisothiazolin-3-one (BIT) resistant strains. In addition, the tRNA 2-thiocytidine (32) synthetase gene (ttcA) was deleted through homologous recombination and the resulting phenotypic changes of the ΔttcA mutant were studied. A total of 3 genes were successfully identified, among which ΔttcA mutant exhibited a reduction in growth rate and swimming motility. On the other hand, an increase in biofilms formation in ΔttcA were observed but not with a significant resistance enhancement to BIT. This work, for the first time, highlights the role of ttcA gene of C. werkmanii strain BF-6 in BIT resistance and biofilm formation.}, } @article {pmid30200345, year = {2018}, author = {Zhu, CT and Mei, YY and Zhu, LL and Xu, Y and Sheng, S and Wang, J}, title = {Recombinant Escherichia coli BL21-pET28a-egfp Cultivated with Nanomaterials in a Modified Microchannel for Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {19}, number = {9}, pages = {}, pmid = {30200345}, issn = {1422-0067}, support = {21676130//National Natural Science Foundation of China/ ; 16KJA530002//Key Project of University Science Research of Jiangsu Province/ ; Year 2015//Shen Lan Young scholars program of Jiangsu University of Science and Technology/ ; }, mesh = {Biocatalysis ; *Biofilms ; Escherichia coli/genetics/*physiology ; Escherichia coli Proteins/genetics/metabolism ; Graphite/chemistry ; Industrial Microbiology/methods ; Microfluidics/*methods ; Nanostructures/*chemistry ; Recombinant Proteins/genetics/metabolism ; }, abstract = {The application of whole cells as catalytic biofilms in microchannels has attracted increasing scientific interest. However, the excessive biomass formation and structure of biofilms in a reactor limits their use. A microchannel reactor with surface modification was used to colonize recombinant Escherichia coil BL21-pET28a-egfp rapidly and accelerated growth of biofilms in the microchannel. The segmented flow system of 'air/culture medium containing nanomaterials' was firstly used to modulate the biofilms formation of recombinant E. coil; the inhibitory effects of nanomaterials on biofilm formation were investigated. The results indicated that the segmental flow mode has a significant impact on the structure and development of biofilms. Using the channels modified by silane reagent, the culture time of biofilms (30 h) was reduced by 6 h compared to unmodified channels. With the addition of graphene sheets (10 mg/L) in Luria-Bertani (LB) medium, the graphene sheets possessed a minimum inhibition rate of 3.23% against recombinant E. coil. The biofilms cultivated by the LB medium with added graphene sheets were stably formed in 20 h; the formation time was 33.33% shorter than that by LB medium without graphene. The developed method provides an efficient and simple approach for rapid preparation of catalytic biofilms in microchannel reactors.}, } @article {pmid30200229, year = {2018}, author = {Phukhamsakda, C and Macabeo, APG and Yuyama, KT and Hyde, KD and Stadler, M}, title = {Biofilm Inhibitory Abscisic Acid Derivatives from the Plant-Associated Dothideomycete Fungus, Roussoella sp.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {9}, pages = {}, pmid = {30200229}, issn = {1420-3049}, support = {PHD/0020/2557//Thailand Research Fund/ ; Georg Forster Grant to APGM//Alexander von Humboldt-Stiftung/ ; PPP grant to M.S. and KDH//Deutscher Akademischer Austauschdienst/ ; }, mesh = {Abscisic Acid/analogs & derivatives/chemistry/*pharmacology ; Anti-Infective Agents/chemistry/*pharmacology ; Ascomycota/chemistry/*genetics ; Biofilms/*drug effects ; Biological Products/chemistry/*pharmacology ; Humans ; Molecular Structure ; }, abstract = {Roussoella species are well recorded from both monocotyledons and dicotyledons. As part of a research program to discover biologically active compounds from plant-associated Dothideomycetes in Thailand, the strain Roussoella sp. (MFLUCC 17-2059), which represents an undescribed species, was isolated from Clematis subumbellata Kurz, fermented in yeast-malt medium and explored for its secondary metabolite production. Bioassay-guided fractionation of the crude extract yielded the new abscisic acid derivative, roussoellenic acid (1), along with pestabacillin B (2), a related congener, and the cyclodipeptide, cyclo(S-Pro-S-Ile) (3). The structure of 1 was determined by 2D NMR spectroscopy and HR-ESIMS data analysis. Compounds 1 and 2 showed inhibitory activity on biofilm formation by Staphylococcus aureus. The biofilm formation of S. aureus was reduced to 34% at 16 µg/mL by roussoellenic acid (1), while pestabacillin B (2) only showed 36% inhibition at 256 µg/mL. In addition, compound 1 also had weak cytotoxic effects on L929 murine fibroblasts and human KB3-1 cancer cells.}, } @article {pmid30199274, year = {2018}, author = {Yin, B and Zhu, L and Zhang, Y and Dong, P and Mao, Y and Liang, R and Niu, L and Luo, X}, title = {The Characterization of Biofilm Formation and Detection of Biofilm-Related Genes in Salmonella Isolated from Beef Processing Plants.}, journal = {Foodborne pathogens and disease}, volume = {15}, number = {10}, pages = {660-667}, doi = {10.1089/fpd.2018.2466}, pmid = {30199274}, issn = {1556-7125}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cattle ; China ; Red Meat/microbiology ; Salmonella/*genetics/*isolation & purification ; Serogroup ; Temperature ; Virulence/genetics ; Virulence Factors/*genetics ; }, abstract = {The biofilm formation behavior of Salmonella isolated from beef processing plants was investigated under varying temperatures (4°C, 10°C, 25°C, 37°C, and 42°C) and pH (4.5, 5.0, 5.5, 6.0, 7.0, and 8.0). The relationships between the presence of biofilm-related genes and the biofilm formation capacity were evaluated. A total of 77 Salmonella strains in 8 different serotypes were assessed: Salmonella Agona (n = 43), Salmonella Senftenberg (n = 13), Salmonella Meleagridis (n = 8), Salmonella Derby (n = 7), Salmonella Kottbus (n = 2), Salmonella Calabar (n = 2), Salmonella Kingston (n = 1), and Salmonella Typhimurium (n = 1). The results showed that all tested Salmonella strains produced biofilm at 25°C and 37°C after 3 d, and Salmonella Kingston and Salmonella Senftenberg had higher biofilm production than other strains under test conditions. Serotype, incubation temperature, pH, and their interactions had significant effects on biofilm formation for Salmonella. The strongest biofilm formation capacity of Salmonella (serovar Agona, Senftenberg, Kottbus, Calabar, Kingston, and Typhimurium) occurred at 25°C and at pH 7.0. Biofilm formation was significantly inhibited for all Salmonella strains incubated at 4°C. The detection rates of genes rpoS, fliC, wcaA, and invA were 100%, and the rates of genes csgB, csgD, csrA, sirA, adrA, gly, fimH, sdiA, ompR, sipB, sipC, luxS, and pfs exceeded 75% among all biofilm producer strains. The detection rate of igaA was significantly different between different biofilm producers. Based on the findings in this study, useful information on biofilm formation of Salmonella isolated from beef processing plants in China is provided, which could help clear the technological hurdle in delaying biofilm production to deal with risks from Salmonella biofilms in the beef industry.}, } @article {pmid30195643, year = {2018}, author = {Vijayakumar, K and Ramanathan, T}, title = {Antiquorum sensing and biofilm potential of 5- Hydroxymethylfurfural against Gram positive pathogens.}, journal = {Microbial pathogenesis}, volume = {125}, number = {}, pages = {48-50}, doi = {10.1016/j.micpath.2018.09.008}, pmid = {30195643}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Furaldehyde/*analogs & derivatives/pharmacology ; Gram-Positive Bacteria/*drug effects/physiology ; Microscopy, Confocal ; Pigments, Biological/*pharmacology ; Quorum Sensing/*drug effects ; }, abstract = {The present investigates the antiquorum sensing and biofilm inhibitory potential of 5 - hydroxymethylfurfural against Chromobacterium violaceum, Streptococcus pyogenes, Streptococcus mutans, Staphylococcus aureus and Staphylococcus epidermidis. 5HMF inhibits the quorum sensing mediated violacein pigment production by 87% at 100 μg/ml concentration. A 100 μg/ml concentration of the compound inhibits S. mutans and S. epidermidis biofilm formation by 86% and 79% whereas for S. pyogenes and S. aureus 125 μg/ml concentration inhibits biofilm formation by 83% and 82%. The Confocal images clearly indicate that 5HMF as a promising antibiofilm agent.}, } @article {pmid30195526, year = {2018}, author = {Zou, M and Liu, D}, title = {A systematic characterization of the distribution, biofilm-forming potential and the resistance of the biofilms to the CIP processes of the bacteria in a milk powder processing factory.}, journal = {Food research international (Ottawa, Ont.)}, volume = {113}, number = {}, pages = {316-326}, doi = {10.1016/j.foodres.2018.07.020}, pmid = {30195526}, issn = {1873-7145}, mesh = {Acids/pharmacology ; Alkalies/pharmacology ; Animals ; Bacteria/drug effects/radiation effects ; *Biofilms ; Dairying/*methods ; Food Handling/*methods ; Hot Temperature ; Hydrogen-Ion Concentration ; Milk/*microbiology ; Powders ; }, abstract = {Owing to the resistance to conventional cleaning and sanitizing agents, biofilms formed on surfaces of dairy processing equipment pose a hazard to the dairy industry. The objective of this study was to evaluate the diversity of the microflora attached to various surfaces of the processing lines of a milk powder processing factory based on 16S rRNA gene sequence analysis. The production of biofilms by the bacterial strains was evaluated on polystyrene (PS) and stainless-steel (SS) surfaces by crystal violet staining method. Especially, effects of temperatures (e.g., 37 °C and 55 °C) and growth mediums (e.g., nutrient broth, NB; tryptic soy broth, TSB) on the production of biofilms by these strains on PS surfaces were explored. Besides, the tolerance of the biofilms of the strains to CIP processes (1.5% v/v HNO3 solution or 2.0% w/v NaOH solution at 80 °C) were analyzed. Forty-five isolates from eleven interior surfaces of the facilities were identified and the distribution of strains had high species diversity, which indicated that multiple spoilage and pathogenic microorganisms remained in milk powder processing lines after CIP processes. Bacteria showed higher biofilm-forming abilities on SS compared to PS surfaces under the same condition. Moreover, effects of the incubation temperature and growth medium on biofilm formation varied between genera, species, and strains. One strain of each species with biofilm-forming abilities on SS surfaces was selected to check the resistance of their biofilms formed on SS coupons to the CIP processes. Biofilms of all of the nine strains were highly or moderately alkali and acid resistant, posing a threat to the milk powder production. These results suggested that organisms within the biofilm might withstand temperature and pH changes better than planktonic organisms. More research is needed to investigate different species isolated from different facilities of the processing lines and to improve the key controlling points in the CIP processes.}, } @article {pmid30193534, year = {2019}, author = {Quendera, AP and Barreto, AS and Semedo-Lemsaddek, T}, title = {Antimicrobial activity of essential oils against foodborne multidrug-resistant enterococci and aeromonads in planktonic and biofilm state.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {25}, number = {2}, pages = {101-108}, doi = {10.1177/1082013218799027}, pmid = {30193534}, issn = {1532-1738}, mesh = {Aeromonas/*drug effects ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cymbopogon ; Drug Resistance, Multiple/*drug effects ; Enterococcus/*drug effects ; Food Microbiology ; Foodborne Diseases/microbiology ; Humans ; Magnoliopsida/*chemistry ; Oils, Volatile/*pharmacology ; Plankton ; Plant Extracts/pharmacology ; Thymus Plant ; }, abstract = {The selection and use of natural compounds with antimicrobial activity against foodborne pathogens is of major importance. The present study evaluated the antimicrobial activity of commercial essential oils against multidrug-resistant Enterococcus spp. and Aeromonas spp. Cymbopogon flexuosus and Thymus vulgaris essential oils presented the highest inhibitory zones against both bacterial groups (p < 0.05). Subsequent determination of the minimum inhibitory concentrations showed values between 0.47 and 1.9 mg/ml for Aeromonas spp. and from 1.9 to 15 mg/ml for Enterococcus spp. The antimicrobial effect of C. flexuosus and T. vulgaris essential oils was also assessed against biofilms. Bacteria in biofilm state were subjected to 30 min or 1 h of exposure to each essential oil and eradication ability estimated by colony counting. Both essential oils exhibited antimicrobial activity against preformed Aeromonas biofilms, but were unable to successfully eradicate biofilms produced by enterococci, in the conditions under investigation. Nonetheless, the presumptive use of essential oils in the food industry should be considered in further investigations.}, } @article {pmid30192766, year = {2018}, author = {Ionescu, AC and Brambilla, E and Azzola, F and Ottobelli, M and Pellegrini, G and Francetti, LA}, title = {Laser microtextured titanium implant surfaces reduce in vitro and in situ oral biofilm formation.}, journal = {PloS one}, volume = {13}, number = {9}, pages = {e0202262}, pmid = {30192766}, issn = {1932-6203}, mesh = {Biofilms/drug effects/*growth & development ; Dental Enamel/microbiology ; *Dental Implants ; Humans ; *Lasers ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Mouth/*microbiology ; Osseointegration/drug effects ; Surface Properties ; Titanium/*chemistry/pharmacology ; }, abstract = {INTRODUCTION: Micro- or nano-topography can both provide antimicrobial properties and improve osseointegration of dental implant titanium surfaces. Laser treatment is one of the best surface microtexturing techniques. The aim of this study was to evaluate in vitro and in situ biofilm formation on a laser-treated titanium surface, comparing it with two conventional surfaces, machined and grit-blasted.

METHODS: For the in vitro experiment, an oral microcosm biofilm model was developed on the surface of titanium disks and reference human enamel using a bioreactor for 48 h. For the in situ experiment, titanium implants with laser-treated, machined and grit-blasted surfaces were mounted on intraoral trays and worn by ten volunteers for 48 h. Biofilm formation was quantitatively evaluated, and surfaces were analyzed using confocal laser scanning microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy.

RESULTS–IN VITRO STUDY: Biofilm structures with a prevalence of viable cells covered most of the machined, grit-blasted and human enamel surfaces, whereas less dense biofilm structures with non-confluent microcolonies were observed on the laser-treated titanium. Laser-treated titanium showed the lowest biofilm formation, where microorganisms colonized the edges of the laser-created pits, with very few or no biofilm formation observed inside the pits.

RESULTS–IN SITU STUDY: The biofilm formation pattern observed was similar to that in the in vitro experiment. Confocal laser scanning microscopy showed complete coverage of the implant threads, with mostly viable cells in grit-blasted and machined specimens. Unexpectedly, laser-treated specimens showed few dead microbial cells colonizing the bottom of the threads, while an intense colonization was found on the threading sides.

CONCLUSION: This data suggests that laser-created microtopography can reduce biofilm formation, with a maximum effect when the surface is blasted orthogonally by the laser beam. In this sense the orientation of the laser beam seems to be relevant for the biological interaction with biofilms.}, } @article {pmid30190485, year = {2018}, author = {Kim, M and Jeon, J and Kim, J}, title = {Streptococcus mutans extracellular DNA levels depend on the number of bacteria in a biofilm.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {13313}, pmid = {30190485}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Culture Media/chemistry ; DNA, Bacterial/*metabolism ; Hydrogen-Ion Concentration ; Streptococcus mutans/*physiology ; }, abstract = {Streptococcus mutans is a component of oral plaque biofilm that accumulates on the surface of teeth. The biofilm consists of extracellular components including extracellular DNA (eDNA). This study was conducted to investigate the factors that may affect the eDNA levels of S. mutans in biofilms. For the study, S. mutans UA159 biofilms were formed for 52 h on hydroxyapatite (HA) discs in 0% (w/v) sucrose +0% glucose, 0.5% sucrose, 1% sucrose, 0.5% glucose, 1% glucose, or 0.5% sucrose +0.5% glucose. Acidogenicity of S. mutans in the biofilms was measured after biofilm formation (22 h) up to 52 h. eDNA was collected after 52 h biofilm formation and measured using DNA binding fluorescent dye, SYBR Green I. Biofilms cultured in 0.5% sucrose or glucose had more eDNA and colony forming units (CFUs) and less exopolysaccharides (EPSs) than the biofilms cultured in 1% sucrose or glucose at 52 h, respectively. The biofilms formed in 0% sucrose +0% glucose maintained pH around 7, while the biofilms grown in 0.5% sucrose had more acidogenicity than those grown in 1% sucrose, and the same pattern was shown in glucose. In conclusion, the results of this study show that the number of S. mutans in biofilms affects the concentrations of eDNA as well as the acidogenicity of S. mutans in the biofilms. In addition, the thickness of EPS is irrelevant to eDNA aggregation within biofilms.}, } @article {pmid30189563, year = {2018}, author = {Abtahi, SM and Petermann, M and Juppeau Flambard, A and Beaufort, S and Terrisse, F and Trotouin, T and Joannis Cassan, C and Albasi, C}, title = {Micropollutants removal in tertiary moving bed biofilm reactors (MBBRs): Contribution of the biofilm and suspended biomass.}, journal = {The Science of the total environment}, volume = {643}, number = {}, pages = {1464-1480}, doi = {10.1016/j.scitotenv.2018.06.303}, pmid = {30189563}, issn = {1879-1026}, mesh = {Biodegradation, Environmental ; Biofilms ; Biomass ; Bioreactors/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; Water Pollutants/*analysis ; }, abstract = {The performance of tertiary moving bed biofilm reactors (MBBRs) was evaluated in terms of micropollutants (MPs) removal from secondary-treated municipal wastewater. After stepwise establishment of a mature biofilm, monitored by scanning electron and confocal microscopies, abiotic and biotic removals of MPs were deeply studied. Since no MPs reduction was observed by the both photodegradation and volatilization, abiotic removal of MPs was ascribed to the sorption onto the biomass. Target MPs i.e. Naproxen, Diclofenac, 17β-Estradiol and 4n-Nonylphenol, arranged in the ascending order of hydrophobicity, abiotically declined up to 2.8%, 4%, 9.5% and 15%, respectively. MPs sorption onto the suspended biomass was found around two times more than the biofilm, in line with MPs' higher sorption kinetic constants (ksor) found for the suspended biomass. When comparing abiotic and biotic aspects, we found that biotic removal outperformed its counterpart for all compounds as Diclofenac, Naproxen, 17β-Estradiol and 4n-Nonylphenol were biodegraded by 72.8, 80.6, 84.7 and 84.4%, respectively. The effect of the changes in organic loading rates (OLRs) was investigated on the pseudo-first order degradation constants (kbiol), revealing the dominant biodegradation mechanism of co-metabolism for the removal of Diclofenac, Naproxen, and 4n-Nonylphenol, while 17β-Estradiol obeyed the biodegradation mechanism of competitive inhibition. Biotic removals and kbiol values of all MPs were also seen higher in the biofilm as compared to the suspended biomass. To draw a conclusion, a quite high removal of recalcitrant MPs is achievable in tertiary MBBRs, making them a promising technology that supports both pathways of co-metabolism and competitive inhibition, next to the abiotic attenuation of MPs.}, } @article {pmid30189320, year = {2018}, author = {Fteita, D and Könönen, E and Gürsoy, M and Ma, X and Sintim, HO and Gürsoy, UK}, title = {Quorum sensing molecules regulate epithelial cytokine response and biofilm-related virulence of three Prevotella species.}, journal = {Anaerobe}, volume = {54}, number = {}, pages = {128-135}, doi = {10.1016/j.anaerobe.2018.09.001}, pmid = {30189320}, issn = {1095-8274}, mesh = {Bacteroidaceae Infections/genetics/*immunology/microbiology ; Biofilms ; Epithelial Cells/*immunology/microbiology ; Gingiva/*immunology/microbiology ; Humans ; Interleukin-1beta/genetics/*immunology ; Interleukin-6/genetics/*immunology ; Interleukin-8/genetics/*immunology ; Keratinocytes/immunology/microbiology ; Prevotella/classification/genetics/pathogenicity/*physiology ; Prevotella intermedia/genetics/pathogenicity/physiology ; Prevotella nigrescens/genetics/pathogenicity/physiology ; *Quorum Sensing ; }, abstract = {Quorum sensing (QS) signaling regulates the motility, adhesion, and biofilm formation of bacteria, and at the same time activates immune response in eukaryotic organisms. We recently demonstrated that the QS molecule, dihydroxy-2, 3-pentanedione (DPD), and its analogs significantly inhibit estradiol-regulated virulence of Prevotella aurantiaca, one of the four species in the Prevotella intermedia group. Here, we examined the combined effects of estradiol and QS signaling on 1) cytokine response of human gingival keratinocytes (HMK) against whole cell extract (WCE) of P. intermedia, Prevotella nigrescens, and Prevotella pallens, and 2) biofilm formation of these three Prevotella species. All experiments were performed in the presence or absence of estradiol, and with different QS molecules: DPD and its analogs (ethyl-DPD, butyl-DPD, and isobutyl-DPD). Concentrations of interleukin (IL)-1β, -6, and -8 were determined by the Luminex multiplex immunoassay, biofilm mass was quantitatively evaluated by measuring protein concentration via the Bradford method, and the microtopography of biofilms was assessed by scanning electron microscopy (SEM) imaging. Concentrations of IL-6 and IL-8 were elevated when HMK cells were incubated with estradiol and WCE of P. intermedia and P. nigrescens, but decreased when incubated with estradiol and WCE of P. pallens. Butyl-DPD neutralized the estradiol- and WCE-induced regulation of HMK interleukin expression and, at the same time, inhibited the biofilm formation of P. intermedia and P. nigrescens. SEM micrographs revealed a decrease in biofilm mass after application of butyl-DPD, which was most detectable among the P. intermedia ATCC 25611 and P. nigrescens ATCC 33563 and AHN 8293 strains. In conclusion, butyl-DPD analog is able to neutralize the WCE-induced epithelial cytokine response and, at the same time, to inhibit the biofilm formation of P. intermedia and P. nigrescens.}, } @article {pmid30188855, year = {2018}, author = {Esfahanizadeh, N and Mirmalek, SP and Bahador, A and Daneshparvar, H and Akhoundi, N and Pourhajibagher, M}, title = {Formation of biofilm on various implant abutment materials.}, journal = {General dentistry}, volume = {66}, number = {5}, pages = {39-44}, pmid = {30188855}, issn = {0363-6771}, mesh = {Aggregatibacter actinomycetemcomitans/growth & development ; Azides ; Bacterial Load ; Biofilms/*growth & development ; Dental Abutments/*microbiology ; Humans ; Porphyromonas gingivalis/growth & development ; Prevotella intermedia/growth & development ; Propidium/analogs & derivatives ; Real-Time Polymerase Chain Reaction ; Saliva/microbiology ; Surface Properties ; Titanium ; Zirconium ; }, abstract = {The characteristics of prosthetic implant components, such as the type, material, and surface roughness of abutments, can affect biofilm formation. Since an ideal abutment surface for the reduction of bacterial adhesion has yet to be found, this in vitro study aimed to quantify biofilm formation on laser-treated titanium, zirconia, and titanium surfaces. Sterile titanium, zirconia, and laser-treated titanium discs were placed in sterile 48-well plates. Biofilm formation was induced by adding sterilized, unstimulated human saliva and suspensions of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and Prevotella intermedia (Pi) to the wells. Viable bacteria in the biofilm were quantified with real-time polymerase chain reaction in conjunction with propidium monoazide. The disc material, the type of bacteria, and their interactions had significant effects on the bacterial counts. On all surfaces, the Pg count was significantly higher than both the Pi and Aa counts (P = 0.0001). The highest count of periodontal pathogens was found on laser-treated surfaces. The second highest and the lowest counts were found on zirconia and titanium surfaces, respectively.}, } @article {pmid30187780, year = {2018}, author = {Maquera-Huacho, PM and Tonon, CC and Correia, MF and Francisconi, RS and Bordini, EAF and Marcantonio, É and Spolidorio, DMP}, title = {In vitro antibacterial and cytotoxic activities of carvacrol and terpinen-4-ol against biofilm formation on titanium implant surfaces.}, journal = {Biofouling}, volume = {34}, number = {6}, pages = {699-709}, doi = {10.1080/08927014.2018.1485892}, pmid = {30187780}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Cells, Cultured ; Cymenes ; Mice ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Porphyromonas gingivalis/drug effects ; Terpenes/*pharmacology ; Titanium/pharmacology ; }, abstract = {This study evaluated the antibacterial properties of carvacrol and terpinen-4-ol against Porphyromonas gingivalis and Fusobacterium nucleatum and its cytotoxic effects on fibroblast cells. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were examined. The minimum biofilm inhibition concentration (MBIC) was evaluated by XTT assay. Biofilm decontamination on titanium surfaces was quantified (CFU ml[-1]), evaluated by confocal laser scanning microscopy (CLSM) and cytotoxic activity by MTT. The MIC and MBC for carvacrol were 0.007% and 0.002% for P. gingivalis and F. nucleatum, and 0.06% for terpinen-4-ol for both microorganisms. The MBIC for carvacrol was 0.03% and 0.06% for P. gingivalis and F. nucleatum, and for terpinen-4-ol was 0.06% and 0.24%. The results indicated anti-biofilm activity using carvacrol (0.26%, 0.06%) and terpinen-4-ol (0.95%, 0.24%) and showed cytotoxic activity similar to chlorohexidine (CHX). However, terpinen-4-ol (0.24%) showed higher cell viability than other treatments. Carvacrol and terpinen-4-ol showed antibacterial activity in respect of reducing biofilms. Moreover, CHX-like cytotoxicity was observed.}, } @article {pmid30187586, year = {2019}, author = {Calvillo-Medina, RP and Martínez-Neria, M and Mena-Portales, J and Barba-Escoto, L and Raymundo, T and Campos-Guillén, J and Jones, GH and Reyes-Grajeda, JP and González-Y-Merchand, JA and Bautista-de Lucio, VM}, title = {Identification and biofilm development by a new fungal keratitis aetiologic agent.}, journal = {Mycoses}, volume = {62}, number = {1}, pages = {62-72}, doi = {10.1111/myc.12849}, pmid = {30187586}, issn = {1439-0507}, mesh = {Aged ; Ascomycota/*classification/genetics/growth & development/*isolation & purification ; Biofilms/*growth & development ; Corneal Ulcer/*microbiology/pathology ; Humans ; Male ; Microbiological Techniques ; Microscopy ; Mycoses/*microbiology/pathology ; Phylogeny ; }, abstract = {BACKGROUND: In recent years, human keratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp. are phytopathogenic and recently have been recognised as a human pathogen, using biofilm formation as a virulence factor.

OBJECTIVES: The aim of this study was isolation, identification (at the species level) and characterisation of a new fungal keratitis agent.

PATIENTS/METHODS: The fungus was isolated from a 67-year-old male patient with a corneal ulcer. Biofilm formation and structure were evaluated by colorimetric methods and microscopy. To identify the fungus, morphological characteristics were examined and a phylogenetic analysis was performed.

RESULTS AND CONCLUSIONS: We report the identification of a fungus, a member of the genus Neoscytalidium which is associated with human keratitis. Phylogenetic analysis and morphological observations on conidiogenous cells, which occur only in arthric chains in aerial mycelium and the coelomycetous synasexual morph is absent, identified a new species, Neoscytalidium oculus sp. nov. The fungus formed biofilm at a concentration of 1 × 10[6]  conidia/mL, during 96 hours of incubation at 37°C, and also manifested haemolysis and melanin production. This is the first report in Latin America of a new species of Neoscytalidium from a clinical isolate has been identified.}, } @article {pmid30186266, year = {2018}, author = {Zhang, Y and Sass, A and Van Acker, H and Wille, J and Verhasselt, B and Van Nieuwerburgh, F and Kaever, V and Crabbé, A and Coenye, T}, title = {Coumarin Reduces Virulence and Biofilm Formation in Pseudomonas aeruginosa by Affecting Quorum Sensing, Type III Secretion and C-di-GMP Levels.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1952}, pmid = {30186266}, issn = {1664-302X}, abstract = {As one of the major pathogens in wound infections, Pseudomonas aeruginosa produces several virulence factors and forms biofilms; these processes are under the regulation of various quorum sensing (QS) systems. Therefore, QS has been regarded as a promising target to treat P. aeruginosa infections. In the present study, we evaluated the effect of the plant-derived QS inhibitor coumarin on P. aeruginosa biofilms and virulence. Coumarin inhibited QS in the P. aeruginosa QSIS2 biosensor strain, reduced protease and pyocyanin production, and inhibited biofilm formation in microtiter plates in different P. aeruginosa strains. The effects of coumarin in inhibiting biofilm formation in an in vitro wound model and reducing P. aeruginosa virulence in the Lucilia sericata infection model were strain-dependent. Transcriptome analysis revealed that several key genes involved in the las, rhl, Pseudomonas quinolone signal (PQS), and integrated QS (IQS) systems were downregulated in coumarin-treated biofilms of P. aeruginosa PAO1. Coumarin also changed the expression of genes related to type III secretion and cyclic diguanylate (c-di-GMP) metabolism. The cellular c-di-GMP level of P. aeruginosa PAO1 and recent clinical P. aeruginosa strains was significantly reduced by coumarin. These results provide new evidence for the possible application of coumarin as an anti-biofilm and anti-virulence agent against P. aeruginosa in wound infections.}, } @article {pmid30186249, year = {2018}, author = {Knight, DB and Rudin, SD and Bonomo, RA and Rather, PN}, title = {Acinetobacter nosocomialis: Defining the Role of Efflux Pumps in Resistance to Antimicrobial Therapy, Surface Motility, and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1902}, pmid = {30186249}, issn = {1664-302X}, support = {IK6 BX004470/BX/BLRD VA/United States ; R01 AI072219/AI/NIAID NIH HHS/United States ; }, abstract = {Acinetobacter nosocomialis is a member of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex. Increasingly, reports are emerging of the pathogenic profile and multidrug resistance (MDR) phenotype of this species. To define novel therapies to overcome resistance, we queried the role of the major efflux pumps in A. nosocomialis strain M2 on antimicrobial susceptibility profiles. A. nosocomialis strains with the following mutations were engineered by allelic replacement; ΔadeB, ΔadeJ, and ΔadeB/adeJ. In these isogenic strains, we show that the ΔadeJ mutation increased susceptibility to beta-lactams, beta-lactam/beta-lactamase inhibitors, chloramphenicol, monobactam, tigecycline, and trimethoprim. The ΔadeB mutation had a minor effect on resistance to certain beta-lactams, rifampicin and tigecycline. In addition, the ΔadeJ mutation resulted in a significant decrease in surface motility and a minor decrease in biofilm formation. Our results indicate that the efflux pump, AdeIJK, has additional roles outside of antibiotic resistance in A. nosocomialis.}, } @article {pmid30185388, year = {2018}, author = {Igumnova, EM and Mishchenko, E and Haug, T and Blencke, HM and Sollid, JUE and Fredheim, EGA and Lauksund, S and Stensvåg, K and Strøm, MB}, title = {Amphipathic sulfonamidobenzamides mimicking small antimicrobial marine natural products; investigation of antibacterial and anti-biofilm activity against antibiotic resistant clinical isolates.}, journal = {Bioorganic & medicinal chemistry}, volume = {26}, number = {17}, pages = {4930-4941}, doi = {10.1016/j.bmc.2018.08.032}, pmid = {30185388}, issn = {1464-3391}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Benzamides/chemistry/*pharmacology ; Biofilms/*drug effects ; Biological Products/chemistry/*pharmacology ; Drug Resistance, Multiple, Bacterial ; Erythrocytes/drug effects ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Hemolysis/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Seawater/chemistry ; Sulfonamides/chemistry/*pharmacology ; }, abstract = {There is an urgent need for novel antimicrobial agents to address the threat of bacterial resistance to modern society. We have used a structural motif found in antimicrobial marine hit compounds as a basis for synthesizing a library of antimicrobial sulfonamidobenzamide lead compounds. Potent in vitro antimicrobial activity against clinically relevant bacterial strains was demonstrated for two compounds, G6 and J18, with minimal inhibitory concentrations (MIC) of 4-16 μg/ml against clinical methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). The two compounds G6 and J18, together with several other compounds of this library, also caused ≥90% eradication of pre-established biofilm of methicillin-resistant S. epidermidis (MRSE) at 40 μg/ml. Using a luciferase assay, the mechanism of action of G6 was shown to resemble the biocide chlorhexidine by targeting the bacterial cell membrane.}, } @article {pmid30185068, year = {2018}, author = {Pezzoni, M and Pizarro, RA and Costa, CS}, title = {Exposure to low doses of UVA increases biofilm formation in Pseudomonas aeruginosa.}, journal = {Biofouling}, volume = {34}, number = {6}, pages = {673-684}, doi = {10.1080/08927014.2018.1480758}, pmid = {30185068}, issn = {1029-2454}, mesh = {Biofilms/growth & development/*radiation effects ; Pseudomonas aeruginosa/*drug effects/physiology ; *Ultraviolet Rays ; }, abstract = {The establishment of bacterial biofilms on abiotic surfaces is a complex process regulated by multiple genetic regulators and environmental factors which are able to modulate the passage of planktonic cells to a sessile state. Solar ultraviolet-A radiation (UVA, 315-400) is one of the main environmental stress factors that bacteria must face at the Earth´s surface. The deleterious effects of UVA are mainly due to oxidative damage. This paper reports that exposure to low UVA doses promotes biofilm formation in three prototypical strains of Pseudomonas aeruginosa, a relevant opportunistic human pathogen. It demonstrates that exposure of planktonic cells to sublethal doses of UVA can increase cell surface hydrophobicity and swimming motility, two parameters known to favor cell adhesion. These results suggest that UVA radiation acts, at least in part, by promoting the first stages of biofilm development.}, } @article {pmid30184789, year = {2018}, author = {Alvarado-Gomez, E and Martínez-Castañon, G and Sanchez-Sanchez, R and Ganem-Rondero, A and Yacaman, MJ and Martinez-Gutierrez, F}, title = {Evaluation of anti-biofilm and cytotoxic effect of a gel formulation with Pluronic F-127 and silver nanoparticles as a potential treatment for skin wounds.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {92}, number = {}, pages = {621-630}, doi = {10.1016/j.msec.2018.07.023}, pmid = {30184789}, issn = {1873-0191}, mesh = {Biofilms/*drug effects/growth & development ; *Cytotoxins/chemistry/pharmacology ; Female ; Fibroblasts/metabolism/pathology ; Humans ; *Hydrogels/chemistry/pharmacology ; Male ; *Metal Nanoparticles/chemistry/therapeutic use ; *Poloxamer/chemistry/pharmacology ; Pseudomonas aeruginosa/*physiology ; *Silver/chemistry/pharmacology ; Skin/*injuries/metabolism/pathology ; Staphylococcus aureus/*physiology ; Wounds and Injuries/*drug therapy/metabolism/pathology ; }, abstract = {The skin wounds cause serious burden to healthcare systems. The lack of sterility of the innate barrier function of the skin facilitates the development of microbial communities within the wound environment especially in biofilm form. Since biofilm is difficult to eradicate, new treatments have been established, such as silver nanoparticles (AgNPs), which antimicrobial and anti-biofilm properties have been studied, nevertheless, their toxic effects are known too. Different concentrations of AgNPs stabilized with a biocompatible and thermo-reversible vehicle as hydrogel Pluronic F-127 were synthesized, those formulations presented interesting thermo-reversibility which could be used to apply on wounds. The formulations (Gel 62.5, 125, and 250 ppm of AgNPs) proposed in this study showed in vitro a total inhibition of clinical strains (Staphylococcus aureus and Pseudomonas aeruginosa) in planktonic form, as well as, anti-biofilm activity was archived with the formulation of Gel 250 ppm, a total inhibition of biofilm formation with mixed culture was registered in the first 30 min of biofilm growth; even more, the viability of human fibroblasts with all gels formulations was >95%, in contrast to silver sulfadiazine cream 1% which showed the highest cytotoxic effect. PF-127 gel with AgNPs could be a prophylactic treatment for skin wounds, because its activity in critical steps on biofilm formation.}, } @article {pmid30183351, year = {2018}, author = {Kim, HJ and Oh, T and Baek, SY}, title = {Multidrug Resistance, Biofilm Formation, and Virulence of Escherichia coli Isolates from Commercial Meat and Vegetable Products.}, journal = {Foodborne pathogens and disease}, volume = {}, number = {}, pages = {}, doi = {10.1089/fpd.2018.2448}, pmid = {30183351}, issn = {1556-7125}, abstract = {Escherichia coli is an important food safety and public health concern because of its pathogenicity and potential for antimicrobial resistance. E. coli isolates as food contaminants and their antimicrobial resistance, biofilm-forming ability, and virulence genes were analyzed to identify the potential of E. coli in food as a major transmission route for antimicrobial resistance and infectious agents. Among the 709 samples of minced meat and fresh vegetable products tested, 18.6% were positive for E. coli. One hundred nine (29.2%) out of 383 E. coli isolates were resistant to 1 or more of the 25 tested antimicrobials. Among the isolates from minced pork, the highest rate of resistance was observed for tetracycline (52.8%), followed by ampicillin (41.6%). The highest resistance rates against tetracycline were coincident with the high amount of tetracycline sold for veterinary use. Because penicillin is the most frequently used antimicrobial in humans, with 4.52 defined daily doses per 1000 people per day, the high rate of resistance to ampicillin (41.6%) supported the potential risk of E. coli food contaminants. However, only 1.3% of the isolates possessed the virulence genes commonly involved in foodborne outbreaks of E. coli. Sixty-seven isolates (17.5%) were multidrug-resistant (MDR), and the highest MDR was observed against 14 antimicrobials. Most of the MDR E. coli isolates showed biofilm-forming ability. Therefore, these isolates will have additional protection from environmental stresses, including antimicrobials. Given the importance of E. coli to food safety and public health, our results on the prevalence of antimicrobial resistance and virulence factors provide useful information for risk management options to protect public health.}, } @article {pmid30181476, year = {2018}, author = {D'Abrosca, G and Paladino, A and Cuoco, E and Marasco, R and Pacifico, S and Piccolella, S and Vastano, V and Sacco, M and Isernia, C and Muscariello, L and Malgieri, G}, title = {Structural Characterization of the Lactobacillus Plantarum FlmC Protein Involved in Biofilm Formation.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {9}, pages = {}, pmid = {30181476}, issn = {1420-3049}, support = {PRIN 20157WZM8A//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; }, mesh = {Amino Acid Sequence ; Bacterial Proteins/*chemistry ; Binding Sites ; Biofilms/*growth & development ; Circular Dichroism ; Ions ; Lactobacillus plantarum/*metabolism ; Lipids/chemistry ; Magnesium/chemistry ; Molecular Docking Simulation ; Mutant Proteins/chemistry ; Protein Aggregates ; Protein Domains ; Reproducibility of Results ; Sequence Analysis, Protein ; Temperature ; }, abstract = {Lactobacillus plantarum is one of the most predominant species in the human gut microbiota of healthy individuals. We have previously characterized some probiotic features of L. plantarum LM3, as the high resistance to different stress, the binding ability toward some extracellular matrix proteins and plasminogen and the immunomodulatory role of the surface expressed adhesin EnoA1. We have also identified the flmA, flmB and flmC genes, coding for putative proteins named FlmA, FlmB and FlmC, whose null mutations partially impaired biofilm development; the L. plantarum LM3[-]6 strain, carrying a deletion in flmC, showed a high rate of autolysis, supporting the hypothesis that FlmC might be involved in cell wall integrity. Here, we report the in-silico characterization of ΔTM-FlmC, a portion of the FlmC protein. The protein has been also expressed, purified and characterized by means of CD spectroscopy, ICP-mass and UHPLC-HRMS. The obtained experimental data validated the predicted model unveiling also the presence of a bound lipid molecule and of a Mg(II) ion. Overall, we provide strong evidences that ΔTM-FlmC belongs to the LytR-CpsA-Psr (LCP) family of domains and is involved in cell envelope biogenesis.}, } @article {pmid30181372, year = {2018}, author = {Ge, X and Cai, Y and Chen, Z and Gao, S and Geng, X and Li, Y and Li, Y and Jia, J and Sun, Y}, title = {Bifunctional Enzyme SpoT Is Involved in Biofilm Formation of Helicobacter pylori with Multidrug Resistance by Upregulating Efflux Pump Hp1174 (gluP).}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {11}, pages = {}, pmid = {30181372}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/drug effects/*growth & development ; Drug Resistance, Multiple, Bacterial/drug effects/*physiology ; Guanosine Pentaphosphate/metabolism ; Helicobacter Infections/drug therapy ; Helicobacter pylori/drug effects/*metabolism ; Humans ; Microbial Sensitivity Tests/methods ; Sheep ; Transcriptional Activation/drug effects/physiology ; Up-Regulation/drug effects/*physiology ; }, abstract = {The drug resistance of Helicobacter pylori is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance (MDR) in bacteria. The ability of H. pylori to form biofilms on the gastric mucosa is known. However, there are few studies on the regulatory mechanisms of H. pylori biofilm formation and multidrug resistance. Guanosine 3'-diphosphate 5'-triphosphate and guanosine 3',5'-bispyrophosphate [(p)ppGpp] are global regulatory factors and are synthesized in H. pylori by the bifunctional enzyme SpoT. It has been reported that (p)ppGpp is involved in the biofilm formation and multidrug resistance of various bacteria. In this study, we found that SpoT also plays an important role in H. pylori biofilm formation and multidrug resistance. Therefore, it was necessary to carry out some further studies regarding its regulatory mechanism. Considering that efflux pumps are of great importance in the biofilm formation and multidrug resistance of bacteria, we tried to determine whether efflux pumps controlled by SpoT participate in these activities. We found that Hp1174 (glucose/galactose transporter [gluP]), an efflux pump of the major facilitator superfamily (MFS), is highly expressed in biofilm-forming and multidrug-resistant (MDR) H. pylori strains and is upregulated by SpoT. Through further research, we determined that gluP is involved in H. pylori biofilm formation and multidrug resistance. Furthermore, the average expression level of gluP in the clinical MDR strains (C-MDR) was considerably higher than that in the clinical drug-sensitive strains (C-DSS). Taken together, our results revealed a novel molecular mechanism of H. pylori resistance to multidrug exposure.}, } @article {pmid30181249, year = {2018}, author = {Kampf, J and Gerwig, J and Kruse, K and Cleverley, R and Dormeyer, M and Grünberger, A and Kohlheyer, D and Commichau, FM and Lewis, RJ and Stülke, J}, title = {Selective Pressure for Biofilm Formation in Bacillus subtilis: Differential Effect of Mutations in the Master Regulator SinR on Bistability.}, journal = {mBio}, volume = {9}, number = {5}, pages = {}, pmid = {30181249}, issn = {2150-7511}, support = {BB/M001180/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/*genetics/physiology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Carrier Proteins/genetics ; *Gene Expression Regulation, Bacterial ; Microfluidic Analytical Techniques ; *Mutation ; Phosphoric Diester Hydrolases/genetics ; Polysaccharides, Bacterial/biosynthesis/genetics ; }, abstract = {Biofilm formation by Bacillus subtilis requires the expression of genes encoding enzymes for extracellular polysaccharide synthesis and for an amyloid-like protein. The master regulator SinR represses all the corresponding genes, and repression of these key biofilm genes is lifted when SinR interacts with its cognate antagonist proteins. The YmdB phosphodiesterase is a recently discovered factor that is involved in the control of SinR activity: cells lacking YmdB exhibit hyperactive SinR and are unable to relieve the repression of the biofilm genes. In this study, we have examined the dynamics of gene expression patterns in wild-type and ymdB mutant cells by microfluidic analysis coupled to time-lapse microscopy. Our results confirm the bistable expression pattern for motility and biofilm genes in the wild-type strain and the loss of biofilm gene expression in the mutant. Moreover, we demonstrated dynamic behavior in subpopulations of the wild-type strain that is characterized by switches in sets of the expressed genes. In order to gain further insights into the role of YmdB, we isolated a set of spontaneous suppressor mutants derived from ymdB mutants that had regained the ability to form complex colonies and biofilms. Interestingly, all of the mutations affected SinR. In some mutants, large genomic regions encompassing sinR were deleted, whereas others had alleles encoding SinR variants. Functional and biochemical studies with these SinR variants revealed how these proteins allowed biofilm gene expression in the ymdB mutant strains.IMPORTANCE Many bacteria are able to choose between two mutually exclusive lifestyles: biofilm formation and motility. In the model bacterium Bacillus subtilis, this choice is made by each individual cell rather than at the population level. The transcriptional repressor SinR is the master regulator in this decision-making process. The regulation of SinR activity involves complex control of its own expression and of its interaction with antagonist proteins. We show that the YmdB phosphodiesterase is required to allow the expression of SinR-repressed genes in a subpopulation of cells and that such subpopulations can switch between different SinR activity states. Suppressor analyses revealed that ymdB mutants readily acquire mutations affecting SinR, thus restoring biofilm formation. These findings suggest that B. subtilis cells experience selective pressure to form the extracellular matrix that is characteristic of biofilms and that YmdB is required for the homeostasis of SinR and/or its antagonists.}, } @article {pmid30180328, year = {2019}, author = {Alizadeh, S and Ghoshal, S and Comeau, Y}, title = {Fate and inhibitory effect of silver nanoparticles in high rate moving bed biofilm reactors.}, journal = {The Science of the total environment}, volume = {647}, number = {}, pages = {1199-1210}, doi = {10.1016/j.scitotenv.2018.08.073}, pmid = {30180328}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Metal Nanoparticles/*analysis/toxicity ; Povidone ; Silver/*analysis/toxicity ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Pollutants, Chemical/*analysis/toxicity ; }, abstract = {Municipal water resource recovery facilities are the primary recipients of a significant fraction of discharged silver nanoparticle (AgNP)-containing wastes, yet the fate and potential risks of AgNPs in attached-growth biological wastewater treatment processes are poorly understood. The fate and inhibitory effects of polyvinylpyrrolidone (PVP)-coated AgNPs at environmentally-relevant nominal concentrations (10, 100, 600 μg/L) were investigated, for the first time, in high rate moving bed biofilm reactors (MBBRs) for soluble organic matter removal. The behavior and removal of continuously added AgNPs were characterized using single-particle inductively coupled plasma mass spectrometry (spICP-MS). While no inhibitory effect at average influent concentration of 10.8 μg/L Ag was observed, soluble COD removal efficiency was significantly decreased at 131 μg/L Ag in 18 days and 631 μg/L Ag in 5 days with suppressed biofilm viability. The inhibitory effect of AgNPs on treatment efficiency was highly correlated to the retained mass of total Ag in attached biofilm on the carriers. Biofilm demonstrated limited retention capacity for AgNPs over 18 days. Considerable mass of Ag (38% to 75%) was released via effluent, predominantly as NPs. We detected some chemically transformed and potentially less toxic forms of silver nanoparticles (Ag2S, AgCl), over the exposure period. This study demonstrated the distinct interaction dynamics, bioavailability and inhibitory effects of AgNPs in a biofilm system. Release of bioavailable AgNPs via effluent and AgNP-rich biofilm, sloughing off the carriers, can affect the treatment chain efficiency of downstream processes. Thus, the inhibitory effects of AgNPs can be a concern even at concentrations as low as 100 to 600 μg/L Ag in biological attached growth wastewater treatments.}, } @article {pmid30179841, year = {2018}, author = {Ni, H and Zhou, X and Zhang, X and Xiao, X and Liu, JF and Huan, H and Luo, Z and Wu, Z}, title = {Feasibility of using basalt fiber as biofilm Carrier to construct bio-nest for wastewater treatment.}, journal = {Chemosphere}, volume = {212}, number = {}, pages = {768-776}, doi = {10.1016/j.chemosphere.2018.08.136}, pmid = {30179841}, issn = {1879-1298}, mesh = {*Biofilms ; Bioreactors/*microbiology ; *Denitrification ; Silicates/*chemistry ; Waste Disposal, Fluid/methods ; Wastewater ; }, abstract = {Generally, biofilms developed for wastewater treatment readily detach from carrier medium once available thickness exceeds about 2 mm. Carrier media made of basalt fibers (BFs) could form ball-like aggregates (more than 10 cm in size, and called bio-nest). To demonstrate its feasibility for wastewater treatment, both reactors with and without BF carriers (RBF and RCO) were evaluated in terms of nutrient removal, oxygen mass transport and biological viabilities as well as biofilm adsorption characteristics. Therefore, oxygen microprofiles and confocal images for bio-nest as well as functional groups for biofilm-attached BF were performed on microsensor systems, confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR). Despite COD:N ratio, both reactors removed about 90% of COD, while only RBF reactor achieved high denitrification capabilities, with nitrogen removal efficiencies varying between 60.10 ± 0.45% and 82.07 ± 0.64%. Microprofile and confocal images showed that dissolved oxygen could reach the core with depth up to 50 mm, at which viable bacteria were detected. Characteristic peaks on FT-IR spectrum demonstrated that various functional groups of polysaccharide and proteins in EPS played a key role in aggregating biofilm-attached BFs into a bio-nest. Thus, BF provides a promising alternative to conventional carrier medium for wastewater treatment.}, } @article {pmid30179497, year = {2018}, author = {Li, B and Qiu, Y and Zhang, J and Huang, X and Shi, H and Yin, H}, title = {Real-Time Study of Rapid Spread of Antibiotic Resistance Plasmid in Biofilm Using Microfluidics.}, journal = {Environmental science & technology}, volume = {52}, number = {19}, pages = {11132-11141}, doi = {10.1021/acs.est.8b03281}, pmid = {30179497}, issn = {1520-5851}, mesh = {*Biofilms ; Conjugation, Genetic ; Drug Resistance, Microbial ; Gene Transfer, Horizontal ; Humans ; *Microfluidics ; Plasmids ; Time and Motion Studies ; }, abstract = {Gene transfer in biofilms is known to play an important role in antibiotic resistance dissemination. However, the process remains poorly understood. In this study, microfluidics with time-lapse imaging was used for real-time monitoring of plasmid-mediated horizontal gene transfer (HGT) in biofilms. Pseudomonas putida KT2440 harboring an antibiotic resistance plasmid RP4 was chosen as the donor while Escherichia coli and activated sludge bacteria were used as the recipient cells. Dynamic features of the transfer process, including the transfer rate, cell growth rate and kinetic changes of the transfer frequency, were determined. It was found that the routes for gene transfer strongly depend on the structure and composition of a biofilm. While intraspecies HGT is essential to initiate a transfer event, the secondary retransfer from transconjugants to the same species is more efficient and can cause cascading gene spread in single-strain biofilms. For the activated sludge biofilm, only small and scattered colonies formed and vertical gene transfer appears to be the dominant route after initial intraspecies transfer. Furthermore, more than 46% of genera in the activated sludge were permissive to plasmid RP4, many of which are associated with human pathogens. These phenomena imply early prevention and interruptions to biofilm structure could provide an effect way to inhibit rapid antibiotic resistance gene spread and reduce the likelihood of catastrophic events associated with antibiotic resistance.}, } @article {pmid30177917, year = {2018}, author = {Zhang, Y and Xu, D and Shi, L and Cai, R and Li, C and Yan, H}, title = {Association Between agr Type, Virulence Factors, Biofilm Formation and Antibiotic Resistance of Staphylococcus aureus Isolates From Pork Production.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1876}, pmid = {30177917}, issn = {1664-302X}, abstract = {Livestock-associated Staphylococcus aureus colonization and/or infections exist in pigs and people in frequent contact with pigs. In this study, a total of 130 S. aureus isolates obtained from different stages of pork production were subjected to antimicrobial susceptibility, biofilm formation, as well as PCR screening to identify virulence genes, and the accessory gene regulator alleles (agr). Among all 130 S. aureus isolates, 109 (83.8%, 109/130) isolates were positive for agr. All swine farms isolates belonged to agr IV, whereas S. aureus isolated from slaughterhouse and retail indicated diverse agr types. All isolates exhibited biofilm formation ability, and raw meat isolates (belonging to agr I) exhibited a greater ability to form strong biofilms than swine farms isolates (belonging to agr IV). agr-positive isolates were associated with more virulence genes than agr-negative isolates. Most biofilm-producing isolates were positive for microbial surface component recognizing adhesive matrix molecule (MSCRAMM), capsule type and ica group genes. The results illustrate a significant association between the prevalence rate of MSCRAMM, capsule type and ica group genes among isolates producing weak, moderate and strong biofilms. The high prevalence of resistance to ciprofloxacin, gentamicin, tetracycline, clarithromycin, clindamycin, and trimethoprim-sulfamethoxazole were mainly observed in moderate and weak biofilm producers. Our findings indicate that S. aureus isolates from pork production displayed diverse molecular ecology.}, } @article {pmid30177768, year = {2018}, author = {Zhang, J and Poh, CL}, title = {Regulating exopolysaccharide gene wcaF allows control of Escherichia coli biofilm formation.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {13127}, pmid = {30177768}, issn = {2045-2322}, mesh = {Acyltransferases/*genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; CRISPR-Associated Protein 9/genetics/metabolism ; CRISPR-Cas Systems ; Escherichia coli/enzymology/*genetics ; Gene Editing/methods ; *Gene Expression Regulation, Bacterial ; Genetic Engineering/methods ; Plasmids/chemistry/metabolism ; Polysaccharides/*biosynthesis/genetics ; Polysaccharides, Bacterial/*biosynthesis/genetics ; RNA, Guide, Kinetoplastida/genetics/metabolism ; }, abstract = {While biofilms are known to cause problems in many areas of human health and the industry, biofilms are important in a number of engineering applications including wastewater management, bioremediation, and bioproduction of valuable chemicals. However, excessive biofilm growth remains a key challenge in the use of biofilms in these applications. As certain amount of biofilm growth is required for efficient use of biofilms, the ability to control and maintain biofilms at desired thickness is vital. To this end, we developed synthetic gene circuits to control E. coli MG1655 biofilm formation by using CRISPRi/dCas9 to regulate a gene (wcaF) involved in the synthesis of colanic acid (CA), a key polysaccharide in E. coli biofilm extracellular polymeric substance (EPS). We showed that the biofilm formation was inhibited when wcaF was repressed and the biofilms could be maintained at a different thickness over a period of time. We also demonstrated that it is also possible to control the biofilm thickness spatially by inhibiting wcaF gene using a genetic light switch. The results demonstrate that the approach has great potential as a new means to control and maintain biofilm thickness in biofilm related applications.}, } @article {pmid30177175, year = {2018}, author = {Tan, Y and Ma, S and Leonhard, M and Moser, D and Haselmann, GM and Wang, J and Eder, D and Schneider-Stickler, B}, title = {Enhancing antibiofilm activity with functional chitosan nanoparticles targeting biofilm cells and biofilm matrix.}, journal = {Carbohydrate polymers}, volume = {200}, number = {}, pages = {35-42}, doi = {10.1016/j.carbpol.2018.07.072}, pmid = {30177175}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Chitosan/*chemistry/*pharmacology ; Microbial Sensitivity Tests ; Silicones/chemistry ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Bacterial biofilms play a key role during infections, which are associated with an increased morbidity and mortality. The classical antibiotic therapy cannot eradicate biofilm-related infections because biofilm bacteria display high drug resistance due to biofilm matrix. Thus, novel drug delivery to overcome biofilm resistance and eliminate biofilm-protected bacteria is needed to be developed. In this study, positively charged chitosan nanoparticles (CSNP) loaded with oxacillin (Oxa) and Deoxyribonuclease I (CSNP-DNase-Oxa) were fabricated. The antibiofilm activity was evaluated against Staphylococcus aureus biofilms. Biofilm architecture on silicone surfaces was investigated by scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) was used to examine live/dead organisms within biofilm. CSNP-DNase-Oxa exhibited higher antibiofilm activity than Oxa-loaded nanoparticles without DNase (CSNP-Oxa) and free Oxa (Oxa and Oxa + DNase) at each concentration in all in-vitro tests. CSNP-DNase-Oxa inhibited biofilm formation in-vitro and eradicated mature biofilm effectively. CSNP-DNase-Oxa could disrupt the biofilm formation through degradation of eDNA, reduced biofilm thickness and the amount of viable cells on silicone. Repeated treatment with CSNP-DNase-Oxa for two days resulted in 98.4% biofilm reduction. Moreover, CSNP-DNase-Oxa was not only able to affect the biofilm of a standard S. aureus strain, but also showed the highest eradication of biofilms of clinical isolates compared with control groups. These results suggest the potential applicability of NPs for the treatment of biofilm-related infections and provide a platform for designing novel drug delivery with more functions.}, } @article {pmid30175689, year = {2020}, author = {Sun, G and Wan, J and Sun, Y and Xie, Y and Ren, S and Wang, Y}, title = {Enhanced biodegradation of pyridine using sequencing batch biofilm reactor under intermittent micro-aerobic condition.}, journal = {Environmental technology}, volume = {41}, number = {8}, pages = {1034-1043}, doi = {10.1080/09593330.2018.1518995}, pmid = {30175689}, issn = {1479-487X}, mesh = {Biodegradation, Environmental ; Biofilms ; *Bioreactors ; Pyridines ; *Waste Disposal, Fluid ; }, abstract = {A sequencing batch biofilm reactor under intermittent micro-aerobic or anaerobic conditions was investigated to remove pyridine at various concentrations from synthetic wastewater. The results showed that over 98% of pyridine (influent concentration ≤200 mg L[-1]) was degraded under intermittent micro-aerobic condition, while about 21% of pyridine was removed under anaerobic condition. Additionally, at least 60% of nitrogen located in the pyridine ring was transformed to ammonium. At the same time, the sulphate reduction was obviously inhibited under intermittent micro-aerobic conditions. The microscopic observation showed that abundant microorganisms were attached on the surface or inside of porous biocarriers under intermittent micro-aerobic conditions after a short-term period of operation. High-throughput sequencing analysis demonstrated that Azotobacter, Rhodobacteraceae and Tolumonas were the dominant species in the intermittent micro-aerobic system. The kinetic study at steady period showed that pyridine degradation was fitted well with the pseudo-first-order model (R[2] > 0.96). The two possible intermediate products were identified and the possible biodegradation pathway of pyridine was proposed under micro-aerobic condition.}, } @article {pmid30174556, year = {2018}, author = {Zhang, Y and Zhang, H and Zhang, Z and Wang, Y and Marhaba, T and Li, J and Sun, C and Zhang, W}, title = {Autohydrogenotrophic Denitrification Using the Membrane Biofilm Reactor for Removing Nitrate from High Sulfate Concentration of Water.}, journal = {Archaea (Vancouver, B.C.)}, volume = {2018}, number = {}, pages = {9719580}, pmid = {30174556}, issn = {1472-3654}, mesh = {Bacteria/classification/genetics ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Biota ; *Denitrification ; Hydrogen/*metabolism ; Membranes/microbiology ; Nitrates/*metabolism ; Sulfates/analysis ; *Wastewater ; Water Pollutants, Chemical/metabolism ; Water Purification/*methods ; }, abstract = {This study investigated the performance of an autohydrogenotrophic membrane biofilm reactor (MBfR) to remove nitrate from water with high sulfate concentrations. The results of simulated running showed that TN removal could be over than 98.8% with the maximum denitrification rate of 134.6 g N/m[3] d under the conditions of the influent sulfate concentrations of 300 mg SO4[2-]/l. The distribution ratio of H2 electron donor for nitrate and sulfate was 70.0 : 26.9 at the high influent loading ratio of sulfate/nitrate of 853.3 g SO4[2-]/m[3] d : 140.5 g N/m[3] d, which indicated that denitrification bacteria (DB) were normally dominated to complete H2 electron with sulfate bacteria (SRB). The results of molecular microbiology analysis showed that the dominated DB were Rhodocyclus and Hydrogenophaga, and the dominated SRB was Desulfohalobium, under the high influent sulfate concentrations.}, } @article {pmid30173098, year = {2018}, author = {Jafari, M and Desmond, P and van Loosdrecht, MCM and Derlon, N and Morgenroth, E and Picioreanu, C}, title = {Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study.}, journal = {Water research}, volume = {145}, number = {}, pages = {375-387}, doi = {10.1016/j.watres.2018.08.036}, pmid = {30173098}, issn = {1879-2448}, mesh = {Biofilms ; *Biofouling ; Filtration ; Membranes, Artificial ; *Ultrafiltration ; }, abstract = {Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through computational models supported by experimental data. Biofilms with homogeneous surface structure were subjected to step-wise changes in flux and transmembrane pressure during compression and relaxation tests. Biofilm thickness under applied forces was measured non-invasively in-situ using optical coherence tomography (OCT). A numerical model of poroelasticity, which couples water flow through the biofilm with biofilm mechanics, was developed to correlate the structural deformation with biofilm hydraulics (permeability and resistance). The computational model enabled extracting mechanical and hydrological parameters corresponding to the experimental data. Homogeneous biofilms under elevated compression forces experienced a significant reduction in thickness while only a slight increase in resistance was observed. This shows that hydraulic resistance of homogeneous biofilms was affected more by permeability decrease due to pore closure than by a decrease in thickness. Both viscoelastic and elastoplastic models could describe well the permanent biofilm deformation. However, for biofilms under study, a simpler elastic model could also be used due to the small irreversible deformations. The elastic moduli fitting the measured data were in agreement with other reported values for biofilm under compression. Biofilm stiffening under larger flow-driven compression forces was observed and described numerically by correlating inversely the elastic modulus with biofilm porosity. The importance of this newly developed method lies in estimation of accurate biofilm mechanical parameters to be used in numerical models for both membrane filtration system and biofouling cleaning strategies. Such model can ultimately be used to identify optimal operating conditions for membrane system subjected to biofouling.}, } @article {pmid30173020, year = {2018}, author = {Zeng, XC and He, Z and Chen, X and Cao, QAD and Li, H and Wang, Y}, title = {Effects of arsenic on the biofilm formations of arsenite-oxidizing bacteria.}, journal = {Ecotoxicology and environmental safety}, volume = {165}, number = {}, pages = {1-10}, doi = {10.1016/j.ecoenv.2018.08.079}, pmid = {30173020}, issn = {1090-2414}, mesh = {Arsenic/metabolism ; Arsenites/*metabolism/toxicity ; Autotrophic Processes ; Bacteria/drug effects/enzymology/isolation & purification/*metabolism ; Bacterial Physiological Phenomena ; Biodegradation, Environmental ; Biofilms/*drug effects ; Heterotrophic Processes ; Oxidation-Reduction ; Oxidoreductases/genetics ; Soil Microbiology ; Soil Pollutants/*metabolism/toxicity ; }, abstract = {Arsenite-oxidizing bacteria (AOB) play a key role in the biogeochemical cycle of arsenic in the environment, and are used for the bioremediation of As contaminated groundwater; however, it is not yet known about how arsenic affects biofilm formations of AOB, and how biofilm formations affect bacterial arsenite-oxidizing activities. To address these issues, we isolated seven novel AOB strains from the arsenic-contaminated soils. They can completely oxidize 1.0 mM As(III) in 22-60 h. Their arsenite oxidase sequences show 43-99% identities to those of other known AOB. Strains Cug1, Cug2, Cug3, Cug4, and Cug6 are able to form biofilms with thickness of 15-95 µm, whereas Cug8 and Cug9 cannot form biofilms. It is interesting to see that arsenite inhibited the biofilm formations of heterotrophic AOB strains, but promoted the biofilm formations of autotrophic strains in a concentration-dependent manner. The arsenite-oxidizing rates of Cug1 and Cug4 biofilms are 31.6% and 27.6% lower than those of their suspension cultures, whereas the biofilm activities of other strains are similar to those of their suspension cultures. The biofilm formation significantly promoted the bacterial resistance to arsenic. This work is the first report on the complex correlations among environmental arsenic, bacterial biofilm formations and bacterial arsenite-oxidizing activities. The data highlight the diverse lifestyle of different AOB under arsenic stress, and provide essential knowledge for the screening of efficient AOB strains used for constructions of bioreactors.}, } @article {pmid30172301, year = {2018}, author = {Yao, H and Kang, M and Wang, Y and Feng, Y and Kong, S and Cai, X and Ling, Z and Chen, S and Jiao, X and Yin, Y}, title = {An essential role for hfq involved in biofilm formation and virulence in serotype 4b Listeria monocytogenes.}, journal = {Microbiological research}, volume = {215}, number = {}, pages = {148-154}, doi = {10.1016/j.micres.2018.07.001}, pmid = {30172301}, issn = {1618-0623}, mesh = {Animals ; Biofilms/*growth & development ; Caco-2 Cells ; Disease Models, Animal ; Drug Tolerance ; Ethanol/pharmacology ; Female ; Gene Deletion ; Gene Expression Profiling ; Host Factor 1 Protein/genetics/*physiology ; Humans ; Lethal Dose 50 ; Listeria monocytogenes/genetics/growth & development/*metabolism/pathogenicity ; Listeriosis/microbiology ; Mice ; Mice, Inbred BALB C ; Octoxynol/pharmacology ; RAW 264.7 Cells ; *Serogroup ; Stress, Physiological ; Virulence/genetics ; Virulence Factors/genetics/*physiology ; }, abstract = {Regulator factor Hfq has been widely detected among both Gram-positive and Gram-negative bacteria; however, its role in Gram-positive bacteria is less well established and varies among species. In Listeria monocytogenes (Lm), an organism able to adapt to a range of environments and live both saprobiotic and parasitic lifestyles, the role of Hfq is not fully understood. Serotype 4b Listeria monocytogenes strains associated with the majority of listeriosis outbreak, while the function of hfq in serotype 4b strains still not referenced. Here, we constructed hfq deletion and reversion mutants of serotype 4b Lm NTSN and analysed the biological characteristics both in vitro and in vivo. The deletion of hfq resulted in a growth deficiency in medium containing 4.5% ethanol or 1% Triton X-100, and the growth of the mutant was significantly reduced at 4 °C. Furthermore, the hfq deletion dramatically decreased biofilm formation in BHI medium and gastric fluid medium, and reduced the invasion and replication rate into the Caco-2BBe cells and RAW264.7 cells. However, complementation restored the wild-type phenotype. Importantly, mouse infection experiments demonstrated that hfq played a more important role in the colonisation and virulence in serotype 4b strain Lm NTSN than in the serotype 1/2a strain Lm EGDe. Taken together, these results demonstrated that hfq is a novel factor associated with biofilm formation, and plays an essential role in the stress response and pathogenisis in serotype 4b strain Lm NTSN. Our data provide the basis for further research into the function of Hfq in serotype 4b Listeria monocytogenes.}, } @article {pmid30172295, year = {2018}, author = {Yang, W and Yan, H and Zhang, J and Gao, Y and Xu, W and Shang, J and Luo, Y}, title = {Inhibition of biofilm formation by Cd[2+] on Bacillus subtilis 1JN2 depressed its biocontrol efficiency against Ralstonia wilt on tomato.}, journal = {Microbiological research}, volume = {215}, number = {}, pages = {1-6}, doi = {10.1016/j.micres.2018.06.002}, pmid = {30172295}, issn = {1618-0623}, mesh = {Bacillus subtilis/*drug effects/growth & development/*physiology ; Biofilms/*drug effects/growth & development ; Cadmium/*pharmacology ; Cadmium Compounds/pharmacology ; Colony Count, Microbial ; Solanum lycopersicum/*microbiology ; Pest Control, Biological/methods ; Plant Diseases/microbiology/prevention & control ; Plant Roots/microbiology ; Ralstonia solanacearum/pathogenicity/*physiology ; Rhizosphere ; Soil/chemistry ; Soil Microbiology ; Sulfates/pharmacology ; }, abstract = {Bacillus subtilis 1JN2 can serve as an effective biocontrol agent against Ralstonia wilt on tomato, but the efficiency of control depends on the levels of heavy metals in the rhizosphere soil. Here, we investigated how the heavy metal Cd[2+] affects the biocontrol efficacy of B.subtilis 1JN2 on Ralstonia wilt. We found that low Cd[2+] content of 2 mM or lower had no effects on the biofilm formation of 1JN2, while media containing 3 mM or higher Cd[2+] levels inhibited biofilm formation. Interestingly, high concentration of Cd[2+] (5 mM) showed inhibition of B.subtilis 1JN2 cell growth. We next tested the effects of Cd[2+] on the colonization of 1JN2 by supplementing artificial Cd[2+] in the tomato rhizosphere in a greenhouse setting. We found that 3 mM Cd[2+] in the tomato rhizosphere inhibited the colonization of B.subtilis 1JN2, Only 10[3] CFU/mL 1JN2 was detected one week post treated with 10[7] CFU/mL but 10[5] CFU/mL could be detected without Cd[2+] in the soil. The presence of Cd[2+] had no effect on the colonization of Ralstonia solanacearum on tomato, but the biocontrol efficacy against Ralstonia wilt by 1JN2 decreased 54.2% when the soil contained 3 mM Cd[2+] compared to the control without Cd[2+]. Taken together, we found that the failure of biofilm formation of Bacillus subtilis 1JN2 that affected by Cd[2+] lead to the decrease of its biocontrol efficacy against Ralstonia wilt on tomato.}, } @article {pmid30172134, year = {2019}, author = {Zhang, M and Wang, L and Xu, M and Zhou, H and Wang, S and Wang, Y and Bai, M and Zhang, C}, title = {Selective antibiotic resistance genes in multiphase samples during biofilm growth in a simulated drinking water distribution system: Occurrence, correlation and low-pressure ultraviolet removal.}, journal = {The Science of the total environment}, volume = {649}, number = {}, pages = {146-155}, doi = {10.1016/j.scitotenv.2018.08.297}, pmid = {30172134}, issn = {1879-1026}, mesh = {Bacteria/genetics/*radiation effects ; *Bacterial Physiological Phenomena ; Biofilms/*radiation effects ; Drinking Water/*analysis ; Drug Resistance, Microbial/*genetics ; *Photolysis ; Ultraviolet Rays ; *Water Purification ; Water Supply ; }, abstract = {The aim of this study was to gain comprehensive insights into the characteristics of antibiotic resistance genes (ARGs) in multiphase samples from drinking water distribution pipelines using a simulated biofilm reactor. During 120 d of continuous operation, common parameters and six ARGs (ermA, ermB, aphA2, ampC, sulII, and tetO) in samples of three phases (water, particle, and biofilm) from the reactor were investigated, which demonstrated secondary contamination by ARGs. Abundances of the six ARGs in the reactor effluent increased gradually, and in the 120 d effluent, the relative abundances of aphA2 and sulII were the highest, at 9.9 × 10[-4] and 1.3 × 10[-3], respectively, with a 1.5-fold and 2.8-fold increase, compared with those in the influent. The relative abundances of the six ARGs in the biofilm phase increased significantly (P < 0.05) at 120 d, which was caused by robust bacteria in biofilm that was newly exposed following the detachment of a large piece of aging biofilm. In the particle phase, four of the ARGs did not change significantly during the 120 d period. The six ARGs in the samples of three phases showed a negative correlation with residual chlorine in the pipe water, which demonstrated that low abundance of ARGs in the samples of three phases was related to the improvement of residual chlorine. The proportion of cultivable bacteria illustrated that the robust and active bacteria were negatively correlated with the six ARGs in the biofilm. Total organic carbon (TOC) in the pipeline showed a positive correlation with the proportion of cultivable bacteria in both the water and biofilm phases, which indicated that a TOC reduction in the pipeline contributed to low abundance of ARGs. With low-pressure ultraviolet (LP-UV) irradiation of 20 mJ/cm[2], ARGs in the samples of three phases were efficiently controlled, which showed that LP-UV can be used for ARG removal in terminal water for supplemental bactericidal treatment of pipeline effluent.}, } @article {pmid30168313, year = {2018}, author = {Tamayo-Ramos, JA and Rumbo, C and Caso, F and Rinaldi, A and Garroni, S and Notargiacomo, A and Romero-Santacreu, L and Cuesta-López, S}, title = {Analysis of Polycaprolactone Microfibers as Biofilm Carriers for Biotechnologically Relevant Bacteria.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {38}, pages = {32773-32781}, doi = {10.1021/acsami.8b07245}, pmid = {30168313}, issn = {1944-8252}, mesh = {*Bacterial Physiological Phenomena ; *Biodegradation, Environmental ; *Biofilms ; Environmental Microbiology ; Polyesters/*chemistry ; }, abstract = {Polymeric electrospun fibers are becoming popular in microbial biotechnology because of their exceptional physicochemical characteristics, biodegradability, surface-to-volume ratio, and compatibility with biological systems, which give them a great potential as microbial supports to be used in production processes or environmental applications. In this work, we analyzed and compared the ability of Escherichia coli, Pseudomonas putida, Brevundimonas diminuta, and Sphingobium fuliginis to develop biofilms on different types of polycaprolactone (PCL) microfibers. These bacterial species are relevant in the production of biobased chemicals, enzymes, and proteins for therapeutic use and bioremediation. The obtained results demonstrated that all selected species were able to attach efficiently to the PCL microfibers. Also, the ability of pure cultures of S. fuliginis (former Flavobacterium sp. ATCC 27551, a very relevant strain in the bioremediation of organophosphorus compounds) to form dense biofilms was observed for the first time, opening the possibility of new applications for this microorganism. This material showed to have a high microbial loading capacity, regardless of the mesh density and fiber diameter. A comparative analysis between PCL and polylactic acid (PLA) electrospun microfibers indicated that both surfaces have a similar bacterial loading capacity, but the former material showed higher resistance to microbial degradation than PLA.}, } @article {pmid30168107, year = {2018}, author = {Xu, G and Abdullah Al, M and Sikder, MNA and Warren, A and Xu, H}, title = {Identifying indicator redundancy of biofilm-dwelling protozoa for bioassessment in marine ecosystems.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {30}, pages = {30441-30450}, pmid = {30168107}, issn = {1614-7499}, mesh = {Aquatic Organisms ; Biofilms ; Ciliophora/*physiology ; *Ecosystem ; Environmental Monitoring/methods ; Seasons ; Seawater ; *Water Quality ; }, abstract = {A multivariate peeling method of data analysis was applied to determine indicator redundancy and for identifying indicator units (IUs) among biofilm-dwelling ciliate communities used for bioassessment of marine water quality. Samples were taken monthly over a 1-year period at four stations in coastal waters of the Yellow Sea: one heavily polluted, one moderately polluted, one intermittently polluted, and one unpolluted. Four IUs (IU1-4) were identified consisting of 22, 13, 14, and 17 species, respectively, out of a total of 144 species. The IUs showed significant correlation with temporal and spatial variations in environmental variables. The redundancy levels of IUs were interchangeable in time and space. However, IU1 and IU2 generally dominated the communities in moderately and intermittently polluted areas during cool (e.g., early spring, late autumn, and winter) and warm (late spring and early autumn) seasons; IU3 dominated in warm seasons (e.g., late spring to autumn) in the heavily polluted area; and IU4 mainly dominated the samples in the unpolluted and moderately polluted areas during the late summer and early autumn. Furthermore, different trophic-functional groupings were represented within the four IUs and these were generally associated with water quality status. These findings suggest that there is high indicator redundancy in marine biofilm-dwelling ciliate communities subjected to different levels of water quality.}, } @article {pmid30166817, year = {2018}, author = {Pakshir, K and Ravandeh, M and Khodadadi, H and Motamedifar, M and Zomorodian, K and Alipour, S}, title = {Evaluation of Exoenzyme Activities, Biofilm Formation, and Co-hemolytic Effect in Clinical Isolates of Candida parapsilosis Species Complex.}, journal = {Journal of global infectious diseases}, volume = {10}, number = {3}, pages = {163-165}, pmid = {30166817}, issn = {0974-777X}, abstract = {Candida parapsilosis species complex is considered as important emerging pathogens and little is known about their pathogenicity factors and co-hemolytic activity with different bacteria species. The aim of this study was to determine in vitro exoenzyme activities, biofilm formation, and co-hemolytic effect of different bacteria species on clinical C. parapsilosis complex isolates. In total, 67 C. parapsilosis complex isolates consist of C. parapsilosis sensu stricto 63/67 and Candida orthopsilosis 4/67 were used in this study. To determine the hemolytic activity of these species, Sabouraud dextrose sheep blood agar was used. Evaluation of the CAMP-like phenomenon carried out in the presence of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus agalactiae. Tube test method with ethylenediaminetetraacetic acid-rabbit plasma was used to determine coagulase activity, and biofilm formation was assessed by the tube method in assist of Sabouraud glucose broth (8%) medium. Fisher's exact tests were used for data statistical analysis. Sixty-six of 67 (98.5%) and 3/67 (4.5%) of the species showed hemolysin and coagulase activity, respectively. Fifty-five of 67 (82.1%) of species had ability for biofilm formation, and none of the samples exhibited co-hemolytic effect in the presence of four mentioned bacteria. No significant difference was found between the level of enzyme production and biofilm formation among the isolates.}, } @article {pmid30166167, year = {2018}, author = {Liu, L and Yan, Y and Feng, L and Zhu, J}, title = {Quorum sensing asaI mutants affect spoilage phenotypes, motility, and biofilm formation in a marine fish isolate of Aeromonas salmonicida.}, journal = {Food microbiology}, volume = {76}, number = {}, pages = {40-51}, doi = {10.1016/j.fm.2018.04.009}, pmid = {30166167}, issn = {1095-9998}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Aeromonas salmonicida/*genetics/isolation & purification ; Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Fishes/*microbiology ; Food Microbiology ; Food Preservation ; *Phenotype ; Quorum Sensing/*genetics ; Transcription Factors/*genetics ; }, abstract = {Microbial spoilage is associated with the regulation of quorum sensing (QS). A. salmonicida AE03 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study the activity and role of AHLs in spoilage phenotypes, motility and biofilm formation of AE03 were investigated. The strain AE03 could induce Chromobacterium violaceum CV026 to produce the violacein pigment both at 28 °C and 4 °C in a density-dependent manner. Five types of AHLs were detected in AE03 culture by LC-MS/MS analysis, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule, reaching the highest concentration when incubated for 30 h at 28 °C. An asaI-mutant, constructed by a suicide plasmid, failed to produce short chain AHLs signal. Compared with wild type (WT) strain, the production of trimethylamine (TMA), biogenic amino and protease significantly increased in asaI-mutant during the exponential and stationary phase, while the growth rate did not differ. Swimming motility in asaI-mutant was comparatively stronger than that of WT strain, whereas, asaI-mutant resulted in the decrease of maturing biofilm. Furthermore, supplementation of exogenous C4-HSL restored the production of spoilage metablites, protease and biofilm formation in mutant. In accordance with the effect of asaI deletion on the spoilage phenotypes and motility, asaI-mutant was showed to significantly up-regulate the transcript levels of torA, cadA and fliR, as well as asaR, indicating that C4-HSL could be involved in the modulation of the spoilage related enzymes and flagella. Indeed, the asaI-mutant promoted the spoilage progress of fish fillets stored at 4 °C, while exogenous C4-HSL repressed the sensory change and TVB-N accumulation. The present study highlighted that AsaI/C4-HSL was an important regulator in spoilage, motility and biofilm formation of A. salmonicida, and spoilage potential was under the negative control of AsaI/AsaR-type system.}, } @article {pmid30166152, year = {2018}, author = {Tango, CN and Akkermans, S and Hussain, MS and Khan, I and Van Impe, J and Jin, YG and Oh, DH}, title = {Modeling the effect of pH, water activity, and ethanol concentration on biofilm formation of Staphylococcus aureus.}, journal = {Food microbiology}, volume = {76}, number = {}, pages = {287-295}, doi = {10.1016/j.fm.2018.06.006}, pmid = {30166152}, issn = {1095-9998}, mesh = {Biofilms/*drug effects/*growth & development ; Environment ; Ethanol/analysis/*pharmacology ; Hydrogen-Ion Concentration ; Sodium Chloride/pharmacology ; Staphylococcus aureus/*drug effects/physiology ; Temperature ; Water/*pharmacology ; }, abstract = {In this work, the effect of environmental factors on Staphylococcus aureus (ATCC 13150) biofilm formation in tryptic soy broth was investigated under different ranges of pH (3.0-9.5), ethanol concentration (EtOH 0.0-20.0%), and aw (NaCl, 0.866-0.992). Biofilm formation was quantified using the crystal violet staining method and optical density (OD: 590 nm) measurements. Biofilm formation was significantly stronger at pH and aw close to S. aureus optimal growth conditions, while it was high at EtOH around 2.5-3.5%. Data sets from the difference between the OD measurements of the test and control (ΔOD) were fitted to the cardinal parameter model (CPM) and cardinal parameter model with inflection (CPMI) to describe the effect of the environmental factors. The models showed good quality of fit for the experimental data in terms of calculated RMSE, with the latter ranging from 0.276 to 0.455. CPM gave a good quality of fit compared to CPMI for the environmental factors tested. Optimal pH was close to neutral (6.76-6.81) and biofilm formation was possible till pH = 3.81-3.78 for CPM and CPMI, respectively. Optimum EtOH and aw conditions for biofilm formation were in the range of 1.99-2.75 and 0.98-0.97, respectively. Predicted OD values observed using strain 13150 were very closely correlated to the OD values predicted with strain 12600 with R[2] of 0.978, 0.991, and 0.947 for pH, EtOH, and aw, respectively. The cultivable bacterial cells within the biofilm were enumerated using standard plate counting and a linear model was applied to correlate the attached biofilm cells to ΔOD of biofilm formation. It was found that the biofilm formation correlated with S. aureus population growth. At 2.5-3.5% of EtOH the maximum population density was lower than that observed at 0.0% of EtOH. As 2.5-3.5% of EtOH initiated a stronger biofilm formation, biofilm formation seems to be induced by ethanol stress. The development of cardinal parameter models to describe the effect environmental factors of importance to biofilm formation, offers a promising predictive microbiology approach to decrypting the S. aureus population growth and survival ability on food processing surfaces.}, } @article {pmid30161132, year = {2018}, author = {Tasse, J and Trouillet-Assant, S and Josse, J and Martins-Simões, P and Valour, F and Langlois-Jacques, C and Badel-Berchoux, S and Provot, C and Bernardi, T and Ferry, T and Laurent, F}, title = {Association between biofilm formation phenotype and clonal lineage in Staphylococcus aureus strains from bone and joint infections.}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0200064}, pmid = {30161132}, issn = {1932-6203}, mesh = {Adult ; Arthritis, Infectious/*microbiology/therapy ; Bacterial Proteins/genetics ; *Biofilms ; Bone Diseases, Infectious/*microbiology/therapy ; Female ; Humans ; Male ; Middle Aged ; Phenotype ; Species Specificity ; Staphylococcal Infections/*microbiology/therapy ; Staphylococcus aureus/*genetics/isolation & purification/*physiology ; Surgical Wound Infection/microbiology/therapy ; Treatment Failure ; Virulence Factors/genetics ; }, abstract = {Biofilm formation is a critical virulence factor responsible for treatment failure and chronicity in orthopaedic device-related infections (ODIs) caused by Staphylococcus aureus. Clonal lineages differ in terms of their biofilm forming capacities. The aim of this study was to investigate the correlation between the clonal complex (CC) affiliation and biofilm phenotype of 30 clinical S. aureus isolates responsible of ODI based on i) early biofilm formation using BioFilm Ring Test® and mature biofilm formation using crystal violet assays, ii) biofilm composition using DNase and proteinase K activity, and iii) prevention of biofilm formation by cloxacillin, teicoplanin and vancomycin using Antibiofilmogram® (biofilm minimal inhibitory concentration-bMIC). In terms of early biofilm formation, the CC30 strains were significantly slower than the CC5, CC15 and CC45 strains. CC45 strains produced significantly more mature biofilm than other group of strains did. The formation of biofilms was highly dependent on the presence of extracellular DNA in the CC5, CC15 and CC30 strains whereas it was mostly dependent on the presence of proteins in CC45. Finally, the CC30 group highlighted higher proportion of susceptible (bMIC < breakpoints of EUCAST guidelines) for cloxacillin, teicoplanin and vancomycin compared to the other CCs. These results demonstrate that the biofilm phenotype of clinical S. aureus isolates from ODIs is strongly related to their respective CC affiliation.}, } @article {pmid30160948, year = {2018}, author = {Vosshage, ATL and Neu, TR and Gabel, F}, title = {Plastic Alters Biofilm Quality as Food Resource of the Freshwater Gastropod Radix balthica.}, journal = {Environmental science & technology}, volume = {52}, number = {19}, pages = {11387-11393}, doi = {10.1021/acs.est.8b02470}, pmid = {30160948}, issn = {1520-5851}, mesh = {Animals ; Biofilms ; Ecosystem ; *Gastropoda ; *Plastics ; Waste Products ; }, abstract = {High amounts of plastic debris enter and accumulate in freshwater systems across the globe. The plastic contamination of benthic habitats in lakes and running waters poses a potential threat to freshwater ecosystems. This study investigates the effects of plastic on two trophic levels of the aquatic food web: primary production, that is, epiplastic biofilm, and primary consumption, that is, a benthic invertebrate grazer. Two plastic types, polymethyl methacrylate (PMMA) and polycarbonate (PC), and glass (control) were used as substrata for natural biofilm establishment. PMMA and PC are, for example, intensively used in the automobile, construction, and electronical industries and in cosmetics (PMMA), CDs, and DVDs (PC). These biofilms were fed to the freshwater gastropod Radix balthica (Linnaeus 1758) in a laboratory-grazing experiment. Biofilm structure and composition were observed using confocal laser scanning microscopy before the grazing experiment. Sublethal effects on R. balthica were observed measuring consumption of biofilm and growth rates. The biofilm composition on PMMA significantly differed compared to PC and glass. The grazing experiments showed limited biofilm consumption and lower growth rates of R. balthica in both plastic treatments. Concluding, plastic in freshwaters has a direct effect on the primary production and an indirect effect on higher trophic levels.}, } @article {pmid30160784, year = {2018}, author = {Borsodi, AK and Anda, D and Makk, J and Krett, G and Dobosy, P and Büki, G and Erőss, A and Mádl-Szőnyi, J}, title = {Biofilm forming bacteria and archaea in thermal karst springs of Gellért Hill discharge area (Hungary).}, journal = {Journal of basic microbiology}, volume = {58}, number = {11}, pages = {928-937}, doi = {10.1002/jobm.201800138}, pmid = {30160784}, issn = {1521-4028}, support = {NK101356//Hungarian Scientific Research Fund (NKFI)/ ; }, mesh = {Archaea/classification/genetics/*physiology/ultrastructure ; Bacteria, Thermoduric/classification/genetics/*physiology/ultrastructure ; Biodiversity ; *Biofilms ; Chemoautotrophic Growth ; DNA, Archaeal/genetics ; DNA, Bacterial/genetics ; Hot Springs/chemistry/*microbiology ; Hungary ; Microbial Consortia/genetics ; Microscopy, Electron, Scanning ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The Buda Thermal Karst System (BTKS) is an extensive active hypogenic cave system located beneath the residential area of the Hungarian capital. At the river Danube, several thermal springs discharge forming spring caves. To reveal and compare the morphological structure and prokaryotic diversity of reddish-brown biofilms developed on the carbonate rock surfaces of the springs, scanning electron microscopy (SEM), and molecular cloning were applied. Microbial networks formed by filamentous bacteria and other cells with mineral crystals embedded in extracellular polymeric substances were observed in the SEM images. Biofilms were dominated by prokaryotes belonging to phyla Proteobacteria, Chloroflexi and Nitrospirae (Bacteria) and Thaumarchaeota (Archaea) but their abundance showed differences according to the type of the host rock, geographic distance, and different water exchange. In addition, representatives of phyla Acidobacteria, Actinobacteria, Caldithrix, Cyanobacteria, Firmicutes Gemmatimonadetes, and several candidate divisions of Bacteria as well as Crenarchaeota and Euryarchaeota were detected in sample-dependent higher abundance. The results indicate that thermophilic, anaerobic sulfur-, sulfate-, nitrate-, and iron(III)-reducing chemoorganotrophic as well as sulfur-, ammonia-, and nitrite-oxidizing chemolithotrophic prokaryotes can interact in the studied biofilms adapted to the unique and extreme circumstances (e.g., aphotic and nearly anoxic conditions, oligotrophy, and radionuclide accumulation) in the thermal karst springs.}, } @article {pmid30159221, year = {2018}, author = {Kord, M and Ardebili, A and Jamalan, M and Jahanbakhsh, R and Behnampour, N and Ghaemi, EA}, title = {Evaluation of Biofilm Formation and Presence of Ica Genes in Staphylococcus epidermidis Clinical Isolates.}, journal = {Osong public health and research perspectives}, volume = {9}, number = {4}, pages = {160-166}, pmid = {30159221}, issn = {2210-9099}, abstract = {OBJECTIVES: Biofilm formation is one of the important features of Staphylococcus epidermidis, particularly in nosocomial infections. We aimed to investigate the biofilm production by phenotypic methods and the presence of ica genes in S epidermidis.

METHODS: A total of 41 S epidermidis isolates were recovered from different clinical specimens. Biofilm formation was evaluated by microtiter plate, tube method and Congo red agar method. The presence of icaA and icaD genes was investigated by PCR. Validity of methods (sensitivity and specificity), and metrics for test performance (positive/negative predictive value, and positive/negative likelihood ratio) were determined.

RESULTS: By both microtiter plate and tube method, 53.6% of S epidermidis isolates were able to produce biofilm, whilst only 24.4% of isolates provided a biofilm phenotype on Congo red agar plates. icaA and icaD genes were found in 100% and 95.1% of isolates, respectively. Biofilm phenotypes accounted for 4.8% by microtiter plate assay, despite the absence of the ica gene. Congo red agar and PCR exhibited a lower sensitivity (18% and 45.5%, respectively) for identifying the biofilm phenotype in comparison to microtiter plate.

CONCLUSION: The microtiter plate method remains generally a better tool to screen biofilm production in S epidermidis. In addition, the ability of S epidermidis to form biofilm is not always dependent on the presence of ica genes, highlighting the importance of ica-independent mechanisms of biofilm formation. The use of reliable methods to specifically detect biofilms can be helpful to treat the patients affected by such problematic bacteria.}, } @article {pmid30159052, year = {2018}, author = {Abdel Halim, RM and Kassem, NN and Mahmoud, BS}, title = {Detection of Biofilm Producing Staphylococci among Different Clinical Isolates and Its Relation to Methicillin Susceptibility.}, journal = {Open access Macedonian journal of medical sciences}, volume = {6}, number = {8}, pages = {1335-1341}, pmid = {30159052}, issn = {1857-9655}, abstract = {AIMS: To evaluate three in vitro phenotypic methods; tissue culture plate, tube method, and Congo red agar for detection of biofilm formation in staphylococci and assess the relation of biofilm formation with methicillin resistance and anti-microbial resistance.

METHODS: The study included 150 staphylococcal isolates. Biofilm detection in staphylococci was performed using tissue culture plate, tube method, and Congo red agar.

RESULTS: Tissue culture plate, tube method, and Congo red agar detected 74%, 42.7%, and 1.3% biofilm producing staphylococci respectively. S. aureus isolates were more common biofilm producers (53.2%) than CONS (46.8%). Biofilm production in CONS species was highest in S. hemolyticus (57.7%). Tube method was 51.4% sensitive, 82.1% specific. As for Congo red agar, sensitivity was very low (0.9%), but specificity was 97.4%. Biofilm producers were mostly; isolated from blood specimens and detected in methicillin-resistant strains 96/111 (86.5%). They were resistant to most antibiotics except vancomycin and linezolid.

CONCLUSIONS: Tissue culture plate is a more quantitative and reliable method for detection of biofilm producing staphylococci compared to tube method and Congo red agar. Hence, it can still be used as a screening method for biofilm detection. Vancomycin and Linezolid are the most sensitive antibiotics among biofilm producing staphylococci.}, } @article {pmid30158585, year = {2018}, author = {Tasse, J and Cara, A and Saglio, M and Villet, R and Laurent, F}, title = {A steam-based method to investigate biofilm.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {13040}, pmid = {30158585}, issn = {2045-2322}, mesh = {Bacteria/*growth & development ; Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Microscopy, Confocal ; Specimen Handling/*methods ; Staining and Labeling ; *Steam ; }, abstract = {Biofilm has become a major topic of interest in medical, food, industrial, and environmental bacteriology. To be relevant, investigation of biofilm behavior requires effective and reliable techniques. We present herein a simple and robust method, adapted from the microplate technique, in which steam is used as a soft washing method to preserve biofilm integrity and to improve reproducibility of biofilm quantification. The kinetics of steam washing indicated that the method is adapted to remove both planktonic bacteria and excess crystal violet (CV) staining for S. aureus, S. epidermidis, S. carnosus, P. aeruginosa, and E. coli biofilm. Confocal laser scanning microscopy confirmed that steam washing preserved the integrity of the biofilm better than pipette-based washing. We also investigated the measurement of the turbidity of biofilm resuspended in phosphate-buffered saline (PBS) as an alternative to staining with CV. This approach allows the discrimination of biofilm producer strains from non-biofilm producer strains in a way similar to CV staining, and subsequently permits quantification of viable bacteria present in biofilm by culture enumeration from the same well. Biofilm quantification using steam washing and PBS turbidity reduced the technical time needed, and data were highly reproducible.}, } @article {pmid30158390, year = {2018}, author = {Morohoshi, T and Oi, T and Aiso, H and Suzuki, T and Okura, T and Sato, S}, title = {Biofilm Formation and Degradation of Commercially Available Biodegradable Plastic Films by Bacterial Consortiums in Freshwater Environments.}, journal = {Microbes and environments}, volume = {33}, number = {3}, pages = {332-335}, pmid = {30158390}, issn = {1347-4405}, mesh = {Bacteria/classification/genetics/isolation & purification/metabolism ; Bacterial Physiological Phenomena ; Biodegradable Plastics/*metabolism ; *Biodegradation, Environmental ; Biodiversity ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; *Fresh Water ; Polyesters/metabolism ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Water Microbiology ; }, abstract = {We investigated biofilm formation on biodegradable plastics in freshwater samples. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) was covered by a biofilm after an incubation in freshwater samples. A next generation sequencing analysis of the bacterial communities of biofilms that formed on PHBH films revealed the dominance of the order Burkholderiales. Furthermore, Acidovorax and Undibacterium were the predominant genera in most biofilms. Twenty-five out of 28 PHBH-degrading isolates were assigned to the genus Acidovorax, while the other three were assigned to the genera Undibacterium and Chitinimonas. These results demonstrated that the order Burkholderiales in biofilms functions as a degrader of PHBH films.}, } @article {pmid30158309, year = {2018}, author = {Michels, J and Stippkugel, A and Lenz, M and Wirtz, K and Engel, A}, title = {Rapid aggregation of biofilm-covered microplastics with marine biogenic particles.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1885}, pages = {}, pmid = {30158309}, issn = {1471-2954}, mesh = {Biofilms/*growth & development ; *Environmental Monitoring ; Particulate Matter/*analysis ; Plastics/*analysis ; *Seawater/chemistry/microbiology ; Water Pollutants/*analysis ; }, abstract = {Ocean plastic pollution has resulted in a substantial accumulation of microplastics in the marine environment. Today, this plastic litter is ubiquitous in the oceans, including even remote habitats such as deep-sea sediments and polar sea ice, and it is believed to pose a threat to ecosystem health. However, the concentration of microplastics in the surface layer of the oceans is considerably lower than expected, given the ongoing replenishment of microplastics and the tendency of many plastic types to float. It has been hypothesized that microplastics leave the upper ocean by aggregation and subsequent sedimentation. We tested this hypothesis by investigating the interactions of microplastics with marine biogenic particles collected in the southwestern Baltic Sea. Our laboratory experiments revealed a large potential of microplastics to rapidly coagulate with biogenic particles, which substantiates this hypothesis. Together with the biogenic particles, the microplastics efficiently formed pronounced aggregates within a few days. The aggregation of microplastics and biogenic particles was significantly accelerated by microbial biofilms that had formed on the plastic surfaces. We assume that the demonstrated aggregation behaviour facilitates the export of microplastics from the surface layer of the oceans and plays an important role in the redistribution of microplastics in the oceans.}, } @article {pmid30154782, year = {2018}, author = {Tan, L and Zhao, F and Han, Q and Zhao, A and Malakar, PK and Liu, H and Pan, Y and Zhao, Y}, title = {High Correlation Between Structure Development and Chemical Variation During Biofilm Formation by Vibrio parahaemolyticus.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1881}, pmid = {30154782}, issn = {1664-302X}, abstract = {The complex three-dimensional structure of biofilms is supported by extracellular polymeric substances (EPSs) and additional insight on chemical variations in EPS and biofilm structure development will inform strategies for control of biofilms. Vibrio parahaemolyticus VPS36 biofilm development was studied using confocal laser scanning microscopy (CLSM) and Raman spectroscopy (RM). The structural parameters of the biofilm (biovolume, mean thickness, and porosity) were characterized by CLSM and the results showed that VPS36 biofilm formed dense structures after 48 h incubation. There were concurrent variations in carbohydrates and nucleic acids contents in the EPS as evidenced by RM. The Raman intensities of the chemical component in EPS, measured using Pearson's correlation coefficient, were positively correlated with biovolume and mean thickness, and negatively correlated with porosity. The Raman intensity for carbohydrates correlated closely with mean thickness (p-value < 0.01) and the Raman intensity for nucleic acid correlated closely with porosity (p-value < 0.01). Additional evidence for these correlations were confirmed using scanning electron microscopic (SEM) and crystal violet staining.}, } @article {pmid30154262, year = {2018}, author = {Chodur, DM and Coulter, P and Isaacs, J and Pu, M and Fernandez, N and Waters, CM and Rowe-Magnus, DA}, title = {Environmental Calcium Initiates a Feed-Forward Signaling Circuit That Regulates Biofilm Formation and Rugosity in Vibrio vulnificus.}, journal = {mBio}, volume = {9}, number = {4}, pages = {}, pmid = {30154262}, issn = {2150-7511}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Calcium/*metabolism ; Cyclic GMP/analogs & derivatives/metabolism ; Environment ; *Gene Expression Regulation, Bacterial ; Phenotype ; Phosphoadenosine Phosphosulfate/metabolism ; *Signal Transduction ; Vibrio vulnificus/genetics/*metabolism ; }, abstract = {Poor clinical outcomes (disfigurement, amputation, and death) and significant economic losses in the aquaculture industry can be attributed to the potent opportunistic human pathogen Vibrio vulnificusV. vulnificus, as well as the bivalves (oysters) it naturally colonizes, is indigenous to estuaries and human-inhabited coastal regions and must endure constantly changing environmental conditions as freshwater and seawater enter, mix, and exit the water column. Elevated cellular c-di-GMP levels trigger biofilm formation, but relatively little is known regarding the environmental signals that initiate this response. Here, we show that calcium is a primary environmental signal that specifically increases intracellular c-di-GMP concentrations, which in turn triggers expression of the brp extracellular polysaccharide that enhances biofilm formation. A transposon screen for the loss of calcium-induced PbrpA expression revealed CysD, an enzyme in the sulfate assimilation pathway. Targeted disruption of the pathway indicated that the production of a specific metabolic intermediate, 3'-phosphoadenosine 5'-phosphosulfate (PAPS), was required for calcium-induced PbrpA expression and that PAPS was separately required for development of the physiologically distinct rugose phenotype. Thus, PAPS behaves as a second messenger in V. vulnificus Moreover, c-di-GMP and BrpT (the activator of brp expression) acted in concert to bias expression of the sulfate assimilation pathway toward PAPS and c-di-GMP accumulation, establishing a feed-forward regulatory loop to boost brp expression. Thus, this signaling network links extracellular calcium and sulfur availability to the intracellular second messengers PAPS and c-di-GMP in the regulation of V. vulnificus biofilm formation and rugosity, survival phenotypes underpinning its evolution as a resilient environmental organism.IMPORTANCE The second messenger c-di-GMP is a key regulator of bacterial physiology. The V. vulnificus genome encodes nearly 100 proteins predicted to make, break, and bind c-di-GMP. However, relatively little is known regarding the environmental signals that regulate c-di-GMP levels and biofilm formation in V. vulnificus Here, we identify calcium as a primary environmental signal that specifically increases intracellular c-di-GMP concentrations, which in turn triggers brp-mediated biofilm formation. We show that PAPS, a metabolic intermediate of the sulfate assimilation pathway, acts as a second messenger linking environmental calcium and sulfur source availability to the production of another intracellular second messenger (c-di-GMP) to regulate biofilm and rugose colony formation, developmental pathways that are associated with environmental persistence and efficient bivalve colonization by this potent human pathogen.}, } @article {pmid30153549, year = {2018}, author = {Liu, X and Wang, L and Pang, L}, title = {Application of a novel strain Corynebacterium pollutisoli SPH6 to improve nitrogen removal in an anaerobic/aerobic-moving bed biofilm reactor (A/O-MBBR).}, journal = {Bioresource technology}, volume = {269}, number = {}, pages = {113-120}, doi = {10.1016/j.biortech.2018.08.076}, pmid = {30153549}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Corynebacterium ; *Denitrification ; Nitrogen ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {A novel bacterium Corynebacterium pollutisoli SPH6 was added in A/O-MBBR system to explore its potential in nitrogen removal. Sodium acetate was found to be its favorable carbon sources compared to glucose, sucrose and methanol. Response surface methodology analysis revealed that SPH6 has the maximum specific degradation rate of total nitrogen (4.9302 mg N/(mg·cells·h[-1])) with the temperature of 30.5 °C, pH of 7.97, inoculation ratio of 7.73% and the ratio of chemical oxygen demand and total nitrogen (COD/TN) of 7.77. The inoculation of SPH6 in A/O-MBBR demonstrated that the strain SPH6 could substantially improve the TN removal efficiency with 20% averagely. The results of high-throughput sequencing showed that the inoculation of SPH6 would essentially improve the microbial community involving nitrogen removal genus such as Hydrogenophaga, Desulfuromonas, and Desulfomicrobium. This study is of importance in providing microbial sources for bioaugmentation in nitrogen removal of wastewater treatment.}, } @article {pmid30153487, year = {2018}, author = {Woischnig, AK and Gonçalves, LM and Ferreira, M and Kuehl, R and Kikhney, J and Moter, A and Ribeiro, IAC and Almeida, AJ and Khanna, N and Bettencourt, AF}, title = {Acrylic microparticles increase daptomycin intracellular and in vivo anti-biofilm activity against Staphylococcus aureus.}, journal = {International journal of pharmaceutics}, volume = {550}, number = {1-2}, pages = {372-379}, doi = {10.1016/j.ijpharm.2018.08.048}, pmid = {30153487}, issn = {1873-3476}, mesh = {Acrylic Resins/administration & dosage ; Animals ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/drug effects ; Cell Line ; Daptomycin/*administration & dosage ; Drug Carriers/*administration & dosage ; Female ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Mice, Inbred C57BL ; Osteoblasts/microbiology ; Polymers/administration & dosage ; Staphylococcal Infections/*drug therapy ; }, abstract = {Daptomycin (DAP) is a cyclic lipopeptide antibiotic with potential clinical application in orthopedic infections caused by staphylococci. However, it failed to eradicate Staphylococcus aureus in vitro, in intracellular infection studies, as well as in vivo in an experimental model of implant-associated biofilm infections. In this study, the antimicrobial effect of DAP encapsulated in poly(methyl methacrylate)-Eudragit (PMMA-EUD) microparticles (DAP-MPs) on intracellular S. aureus was evaluated in human osteoblast cells using fluorescence in situ hybridization (FISH) analysis. Encapsulated DAP was able to reduce the amount of intracellular S. aureus by 73% compared to blank microparticles (MPs). Then, the advantage of treating with DAP-MPs versus free DAP was evaluated in a murine model of implant-associated biofilm infection. Free DAP showed a >3 log10 decrease in planktonic and adherent bacteria but failed to eradicate adherent methicillin-resistant S. aureus (MRSA), whereas DAP-MPs showed a clearance of planktonic MRSA, significantly reduced adherent MRSA by more than 3 log10 and cured the infection in 60%. This was linked to the prolonged higher DAP concentration within the tissue cage fluid compared to free DAP. To our knowledge, this study provides the first evidence for the high intracellular and in vivo anti-biofilm efficacy of DAP-MPs to target staphylococcal infections.}, } @article {pmid30153380, year = {2019}, author = {Yong, YY and Dykes, G and Lee, SM and Choo, WS}, title = {Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.}, journal = {Journal of applied microbiology}, volume = {126}, number = {1}, pages = {68-78}, doi = {10.1111/jam.14091}, pmid = {30153380}, issn = {1365-2672}, support = {//School of Science, Monash University Malaysia/ ; }, mesh = {Amaranthus/*chemistry ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Betacyanins/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Cactaceae/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/isolation & purification/*pharmacology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml[-1]) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml[-1]) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.

CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.

This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.}, } @article {pmid30153375, year = {2018}, author = {Rossi, E and Paroni, M and Landini, P}, title = {Biofilm and motility in response to environmental and host-related signals in Gram negative opportunistic pathogens.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/jam.14089}, pmid = {30153375}, issn = {1365-2672}, support = {R88-A3537//Rigshospitalets Rammebevilling 2015-17/ ; R167-2013-15229//Lundbeckfonden/ ; NNF15OC0017444//Novo Nordisk Fonden/ ; R144-A5287//RegionH Rammebevilling/ ; 2- 2018//Department of Biosciences, University of Milan/ ; }, abstract = {Most bacteria can switch between a planktonic, sometimes motile, form and a biofilm mode, in which bacterial cells can aggregate and attach to a solid surface. The transition between these two forms represents an example of bacterial adaptation to environmental signals and stresses. In 'environmental pathogens', namely, environmental bacteria that are also able to cause disease in animals and humans, signals associated either with the host or with the external environment, such as temperature, oxygen availability, nutrient concentrations etc., play a major role in triggering the switch between the motile and the biofilm mode, via complex regulatory mechanisms that control flagellar synthesis and motility, and production of adhesion factors. In this review article, we present examples of how environmental signals can impact biofilm formation and cell motility in the Gram negative bacteria Pseudomonas aeruginosa, Escherichia coli and in the Burkholderia genus, and how the switch between motile and biofilm mode can be an essential part of a more general process of adaptation either to the host or to the external environment.}, } @article {pmid30149732, year = {2018}, author = {Gerbersdorf, SU and Wieprecht, S and Thom, M and Paterson, DM and Scheffler, M}, title = {New insights into MagPI: a promising tool to determine the adhesive capacity of biofilm on the mesoscale.}, journal = {Biofouling}, volume = {34}, number = {6}, pages = {618-629}, doi = {10.1080/08927014.2018.1476971}, pmid = {30149732}, issn = {1029-2454}, mesh = {Adhesiveness ; *Biofilms ; *Magnetic Fields ; }, abstract = {The adhesiveness and stability of ubiquitously distributed biofilms is a significant issue in many areas such as ecology, biotechnology and medicine. The magnetic particle induction (MagPI) system allows precise determinations of biofilm adhesiveness at high temporal and spatial resolution on the mesoscale. This paper concerns several technical aspects to further improve the performance of this powerful experimental approach and enhance the range of MagPI applications. First, several electromagnets were built to demonstrate the influence of material and geometry with special regard to core remanence and magnetic strength. Secondly, the driving force to lift up the particles was evaluated and it was shown that both the magnetic field strength and the magnetic field gradient are decisive in the physics of the MagPI approach. The intricate combination of these two quantities was demonstrated with separate experiments that add permanent magnets to the MagPI system.}, } @article {pmid30149130, year = {2018}, author = {Lotha, R and Shamprasad, BR and Sundaramoorthy, NS and Ganapathy, R and Nagarajan, S and Sivasubramanian, A}, title = {Zero valent silver nanoparticles capped with capsaicinoids containing Capsicum annuum extract, exert potent anti-biofilm effect on food borne pathogen Staphylococcus aureus and curtail planktonic growth on a zebrafish infection model.}, journal = {Microbial pathogenesis}, volume = {124}, number = {}, pages = {291-300}, doi = {10.1016/j.micpath.2018.08.053}, pmid = {30149130}, issn = {1096-1208}, mesh = {Animals ; Biofilms/*drug effects ; Capsicum/*chemistry ; Disease Models, Animal ; Female ; Humans ; Male ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Plankton/drug effects/growth & development/physiology ; Plant Extracts/chemistry/*pharmacology ; Silver/chemistry/*pharmacology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects/growth & development/physiology ; Zebrafish ; }, abstract = {Food plants Hungarian wax pepper (HWP) and Green Bell pepper (GBP), belonging to Capsicum annuum were utilized for biogenic fabrication of zero valent, nano-silver (AgNPs) through a photo-mediation procedure. In the bacterial strains evaluated, HWP/GBP AgNPs demonstrated effective bacteriostatic and bactericidal effect against Staphylococcus aureus. Time kill results portrayed that HWP/GBP nano-silver exhibited comparable bactericidal potency on S. aureus. Anti-biofilm potential of HWP/GBP AgNPs displayed significant effects at sub MIC levels, by triggering 50% biofilm reduction of the food spoilage microbe S. aureus, inferring that the anti-biofilm outcome is not dependent on antibacterial result, and this was confirmed by SEM and fluorescence studies. Histopathological analyses of S. aureus infected zebrafish liver did not display any abnormality changes such as extensive cell death and degeneration, upon treatment with HWP/GBP AgNPs and the zero-valent silver nanoparticles were comparatively less toxic and more operative in restraining the bioburden in S. aureus infected zebrafish model by a >1.7 log fold. Ability of light reduced HWP/GBP AgNPs to alleviate the in vitro and in vivo planktonic mode of growth and curb the biofilm formation of S. aureus is also demonstrated.}, } @article {pmid30148865, year = {2018}, author = {Tran, VN and Dasagrandhi, C and Truong, VG and Kim, YM and Kang, HW}, title = {Antibacterial activity of Staphylococcus aureus biofilm under combined exposure of glutaraldehyde, near-infrared light, and 405-nm laser.}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0202821}, pmid = {30148865}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/radiation effects ; Glutaral/*pharmacology ; *Infrared Rays ; Microscopy, Electron, Scanning ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/*physiology ; }, abstract = {Healthcare-associated infections have increasingly become problematic in the endoscopic procedures resulting in several severe diseases such as carbapenem-resistant Enterobacteriaceae (CRE)-related infections, pneumonia, and bacteremia. Especially, some bacterial strains are resistant to traditional antimicrobials. Therefore, the necessity of developing new antibiotics or management to deal with bacterial infections has been increasing. The current study combined a low concentration of glutaraldehyde (GTA) with near-infrared (NIR) light and 405-nm laser to entail antibacterial activity on Staphylococcus aureus biofilm. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and colony forming unit (CFU) counting were used to quantify the viable cells while fluorescent and scanning electron microscopic images were used to qualitatively evaluate the cell membrane integrity and structural deformation, respectively. Practically, S. aureus biofilm was highly susceptible (7% cell viability and 6.8-log CFU/cm2 bacterial reduction for MTT assay and CFU analysis, respectively) to the combination of GTA (0.1%), NIR light (270 J/cm2), and 405-nm laser (288 J/cm2) exposure. GTA could form either DNA-protein or protein-protein crosslinks to inhibit DNA and protein synthesis. The NIR light induced the thermal damage on protein/enzymes while 405-nm laser could induce reactive oxygen species (ROS) to damage the bacterial membrane. Thus, the proposed technique may be a feasible modality for endoscope cleaning to prevent any secondary infection in the healthcare industry.}, } @article {pmid30142888, year = {2018}, author = {Mensi, M and Cochis, A and Sordillo, A and Uberti, F and Rimondini, L}, title = {Biofilm Removal and Bacterial Re-Colonization Inhibition of a Novel Erythritol/Chlorhexidine Air-Polishing Powder on Titanium Disks.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {9}, pages = {}, pmid = {30142888}, issn = {1996-1944}, abstract = {Air-polishing with low abrasiveness powders is fast arising as a valid and mini-invasive instrument for the management of biofilm colonizing dental implants. In general, the reported advantage is the efficient removal of plaque with respect to the titanium integrity. In the present study, we evaluated the in situ plaque removal and the preventive efficacy in forestalling further infection of an innovative erythritol/chlorhexidine air-polishing powder and compared it with sodium bicarbonate. Accordingly, two peri-implantitis-linked biofilm formers, strains Staphylococcus aureus and Aggregatibacter actinomycetemcomitans, were selected and used to infect titanium disks before and after the air-polishing treatment to test its ability in biofilm removal and re-colonization inhibition, respectively. Biofilm cell numbers and viability were assayed by colony-forming unit (CFU) count and metabolic-colorimetric (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) (XTT) assay. Results demonstrated that air-polishing performed with either sodium bicarbonate or erythritol/chlorhexidine was effective in reducing bacteria biofilm viability and number on pre-infected specimens, thus showing a similar ability in counteracting existing infection in situ; on the other hand, when air-polished pre-treated disks were infected, only erythritol/chlorhexidine powder showed higher post-treatment biofilm re-growth inhibition. Finally, surface analysis via mechanical profilometry failed to show an increase in titanium roughness, regardless of the powder selected, thus excluding any possible surface damage due to the use of either sodium bicarbonate or erythritol/chlorhexidine.}, } @article {pmid30142702, year = {2019}, author = {Ely, VL and Vargas, AC and Costa, MM and Oliveira, HP and Pötter, L and Reghelin, MA and Fernandes, AW and Pereira, DIB and Sangioni, LA and Botton, SA}, title = {Moraxella bovis, Moraxella ovis and Moraxella bovoculi: biofilm formation and lysozyme activity.}, journal = {Journal of applied microbiology}, volume = {126}, number = {2}, pages = {369-376}, doi = {10.1111/jam.14086}, pmid = {30142702}, issn = {1365-2672}, mesh = {Animals ; *Biofilms ; Cattle ; Cattle Diseases ; Keratoconjunctivitis, Infectious ; Moraxella/isolation & purification/*physiology ; Moraxella bovis/*physiology ; Moraxellaceae Infections ; Muramidase/*metabolism ; Sheep/microbiology ; }, abstract = {AIMS: This study aimed to verify the formation of biofilms by Moraxella bovis, Moraxella ovis and Moraxella bovoculi isolates from ruminants. In addition, the lysozyme activity against the isolates of M. bovis, M. ovis and M. bovoculi in free form and in biofilms was determined.

METHODS AND RESULTS: In this study, 54 isolates of Moraxella sp. obtained from bovine and ovine clinical samples were evaluated in vitro for capacity of biofilm formation and lysozyme susceptibility in planktonic and sessile cells. In addition, biofilms produced by four Moraxella sp. isolates were visualized under scanning electron microscope (SEM). It was possible to demonstrate, for the first time, the ability to form biofilms by M. ovis and M. bovoculi. The isolates of Moraxella sp. have the capacity to form biofilms in different intensities, varying among weak, moderate and strong. It was verified that the lysozyme shows activity on Moraxella sp. in planktonic form. However, on biofilms there was a reduction in the production, but without impairing its formation, and on consolidated biofilms the lysozyme did not have the capacity to eradicate the preformed biofilms.

CONCLUSIONS: This work shows the capacity of biofilm formation by Moraxella sp. of veterinary importance. The lysozyme susceptibility of Moraxella sp. in planktonic form shows that this enzyme has bacteriostatic activity on this micro-organism and it reduced the production of biofilms.

Based on the results, it is possible to infer that the biofilm formation capacity by Moraxella sp. and the resistance to lysozyme concentrations equal to or greater than the physiological levels of the ruminant tear may be linked not only to the capacity to colonize the conjunctiva, but also to remain in this place even after healing of the lesions, being a reservoir of Moraxella sp. in a herd.}, } @article {pmid30142222, year = {2018}, author = {Santos, SS and Augusto, DG and Alves, PAC and Pereira, JS and Duarte, LMB and Melo, PC and Gross, E and Kaneto, CM and Silva, A and Santos, JL}, title = {Trichoderma asperelloides ethanolic extracts efficiently inhibit Staphylococcus growth and biofilm formation.}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0202828}, pmid = {30142222}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Wall/drug effects/metabolism ; Ethanol/*chemistry ; Staphylococcus aureus/cytology/*drug effects/*physiology ; Trichoderma/*chemistry ; }, abstract = {Fungi from the widely distributed genus Trichoderma are of great biotechnological interest, being currently used in a vast range of applications. Here, we report that high-molecular weight fraction (HWF) derived from Trichoderma asperelloides ethanolic extract exhibits antibiotic activity against staphylococcal biofilms. The antibacterial and anti-biofilm properties of T. asperelloides extracts were evaluated by well-established assays in Staphylococcus aureus ATCC strains (29213 and 6538) and in one clinical isolate from bovine mastitis. The HWF from T. asperelloides eradicated S. aureus by causing substantial matrix de-structuring and biomass reduction (p < 10-5) at concentrations as low as 2.3 μg mL-1. Additionally, we present ultra-structure analysis by the use of scanning electron microscopy as well as transmission microscopy, which showed that T. asperelloides killed cells through cell wall and membrane disturbance. Remarkably, the HWF from T. asperelloides killed S. aureus and eradicated its biofilms in a greater performance than gentamicin (p < 10-5), a known potent antibiotic against S. aureus. Our results indicate that extract from T. asperelloides may represent a promising candidate for the development of new antibiotics against gram-positive bacteria.}, } @article {pmid30142035, year = {2019}, author = {Cepas, V and López, Y and Muñoz, E and Rolo, D and Ardanuy, C and Martí, S and Xercavins, M and Horcajada, JP and Bosch, J and Soto, SM}, title = {Relationship Between Biofilm Formation and Antimicrobial Resistance in Gram-Negative Bacteria.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {25}, number = {1}, pages = {72-79}, doi = {10.1089/mdr.2018.0027}, pmid = {30142035}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Ceftazidime/pharmacology ; Ciprofloxacin/pharmacology ; Cross Infection/drug therapy/microbiology ; Drug Resistance, Multiple, Bacterial/*drug effects/*physiology ; Gram-Negative Bacteria/drug effects/*physiology ; Gram-Negative Bacterial Infections/*drug therapy/*microbiology ; Humans ; Microbial Sensitivity Tests/methods ; Virulence/genetics ; beta-Lactamases/genetics ; }, abstract = {Gram-negative microorganisms are a significant cause of infection in both community and nosocomial settings. The increase, emergence, and spread of antimicrobial resistance among bacteria are the most important health problems worldwide. One of the mechanisms of resistance used by bacteria is biofilm formation, which is also a mechanism of virulence. This study analyzed the possible relationship between antimicrobial resistance and biofilm formation among isolates of three Gram-negative bacteria species. Several relationships were found between the ability to form biofilm and antimicrobial resistance, being different for each species. Indeed, gentamicin and ceftazidime resistance was related to biofilm formation in Escherichia coli, piperacillin/tazobactam, and colistin in Klebsiella pneumoniae, and ciprofloxacin in Pseudomonas aeruginosa. However, no relationship was observed between global resistance or multidrug-resistance and biofilm formation. In addition, compared with other reported data, the isolates in the present study showed higher rates of antimicrobial resistance. In conclusion, the acquisition of specific antimicrobial resistance can compromise or enhance biofilm formation in several species of Gram-negative bacteria. However, multidrug-resistant isolates do not show a trend to being greater biofilm producers than non-multiresistant isolates.}, } @article {pmid30141343, year = {2018}, author = {Roth, SR and Henkel, K and Altenburger, MJ and Auwärter, V and Neukamm, MA}, title = {Multivariate optimization of a method for the determination of fatty acids in dental biofilm by GC-MS.}, journal = {Bioanalysis}, volume = {10}, number = {16}, pages = {1319-1333}, doi = {10.4155/bio-2018-0106}, pmid = {30141343}, issn = {1757-6199}, mesh = {*Biofilms ; Dental Plaque/*microbiology ; Esterification ; Fatty Acids/*analysis/*chemistry ; *Gas Chromatography-Mass Spectrometry ; Multivariate Analysis ; Reproducibility of Results ; Temperature ; }, abstract = {AIM: Phospholipid fatty acid methyl ester (FAME) analysis offers a simple option additionally to 16S rRNA sequencing to characterize microbial communities and to monitor changes. A method was established for the characterization of dental plaque via FAME profiles.

METHODOLOGY: Fatty acids were determined as FAMEs (direct, acidic transesterification) and analyzed by GC-MS using an optimized temperature gradient. The transesterification reaction was optimized using a fractional factorial central composite face-centered design.

RESULTS: Optimal conditions for the transesterification in methanol/toluene: hydrochloric acid concentration 2% (w/v), reaction time 40 min, temperature 110 °C. Method validation showed satisfactory accuracy, precision and linearity.

CONCLUSION: The method provides a useful tool to characterize plaque via FAME profiles and was successfully applied to samples from ten subjects demonstrating its applicability.}, } @article {pmid30140417, year = {2018}, author = {Mirani, ZA and Fatima, A and Urooj, S and Aziz, M and Khan, MN and Abbas, T}, title = {Relationship of cell surface hydrophobicity with biofilm formation and growth rate: A study on Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli.}, journal = {Iranian journal of basic medical sciences}, volume = {21}, number = {7}, pages = {760-769}, pmid = {30140417}, issn = {2008-3866}, abstract = {OBJECTIVES: This study was designed to determine the relationship of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli isolates in multispecies biofilms and their individual phenotypic characters in biofilm consortia.

MATERIALS AND METHODS: The subject isolates were recovered from different food samples and identified on the basis of growth on differential and selective media. Tube methods, Congo-red agar method, and scanning electron microscopy (SEM) were used to study biofilms phenotypes. The hydrophobicity of the strains was evaluated by the adhesion to apolar solvent.

RESULTS: The results showed that E. coli dominated the pre-biofilm stage. It has been observed that E. coli adopted biofilm life much before S. aureus and P. aeruginosa. However, after adopting biofilm lifestyle, slowly and gradually, P. aeruginosa dominated the consortia and dispersed other stakeholders. The subject isolates of P. aeruginosa produce cis-2-decanoic acid to disperse or inhibit S. aureus and E. coli biofilms. Gas-chromatography and mass spectrometry results showed that cis-2-decanoic was higher in the co-culture condition and increased at late log-phase or at stationary phase. Although majority of S. aureus were unable to compete with P. aeruginosa, however, a minor population competed, survived, and persisted in biofilm consortia as small colony variants. The survivors showed higher expression of sigB and sarA genes. P. aeruginosa showed comparatively higher hydrophobic surface properties.

CONCLUSION: Comparative analysis showed that cell surface hydrophobicity, growth rate, and small colony variants (SCVs) are correlated in biofilm consortia of the P. aeruginosa, S. aureus, and E. coli.}, } @article {pmid30138443, year = {2018}, author = {Ranfaing, J and Dunyach-Remy, C and Lavigne, JP and Sotto, A}, title = {Propolis potentiates the effect of cranberry (Vaccinium macrocarpon) in reducing the motility and the biofilm formation of uropathogenic Escherichia coli.}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0202609}, pmid = {30138443}, issn = {1932-6203}, mesh = {Biofilms/drug effects ; Cell Movement/drug effects ; Escherichia coli Infections/*drug therapy/microbiology ; Humans ; Plant Extracts/chemistry/pharmacology ; Propolis/chemistry/*pharmacology ; Uropathogenic Escherichia coli/*drug effects/pathogenicity ; Vaccinium macrocarpon/*chemistry ; }, abstract = {One strategy to prevent urinary tract infections is the use of natural products such as cranberry (Vaccinium macrocarpon) and propolis. The objective of this study was to evaluate the impact of these products alone and combined on the motility and biofilm formation of a collection of representative uropathogenic Escherichia coli (UPEC). Motility was evaluated by the swarming and swimming capacity of the isolates in presence/absence of cranberry ± propolis. Early and late biofilm formation was observed with the Biofilm Ring test (BioFilm Control) and the crystal violet method. Cranberry alone was seen to have a variable effect on motility and biofilm formation unrelated to bacterial characteristics, but a reduced motility and biofilm formation was observed for all the isolates in the presence of cranberry + propolis. These results suggest that cranberry alone doesn't work on all the E. coli strains and propolis potentiates the effect of cranberry on UPEC, representing a new strategy to prevent recurrent urinary tract infections.}, } @article {pmid30137191, year = {2019}, author = {Carvajal, J and Carvajal, M and Hernández, G}, title = {Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?.}, journal = {Aesthetic surgery journal}, volume = {39}, number = {8}, pages = {848-859}, doi = {10.1093/asj/sjy216}, pmid = {30137191}, issn = {1527-330X}, mesh = {Administration, Cutaneous ; Adolescent ; Adult ; Anti-Infective Agents, Local/*administration & dosage ; *Biofilms ; Breast Implantation/*adverse effects ; Chlorhexidine/administration & dosage/analogs & derivatives ; Female ; Follow-Up Studies ; Humans ; Implant Capsular Contracture/diagnosis/epidemiology/microbiology/*prevention & control ; Microbiota/drug effects ; Middle Aged ; Povidone-Iodine/administration & dosage ; Preoperative Care ; Skin/microbiology ; Staphylococcal Infections/diagnosis/epidemiology/microbiology/*prevention & control ; Staphylococcus epidermidis/isolation & purification ; Young Adult ; }, abstract = {BACKGROUND: Capsular contracture (CC) has remained an unresolved issue throughout history. Strong evidence focuses on bacterial biofilm as its main source. A literature review revealed that more than 90% of bacteria found in capsules and implants removed from patients with Baker grade III-IV CC belong to the resident skin microbiome (Staphylococcus epidermidis, predominant microorganism). The use of an adequate preoperative skin antiseptic may be a critical step to minimize implant contamination and help prevent biofilm-related CC.

OBJECTIVES: The authors sought to compare the effect of 2 different antiseptic skin preparations: povidone-iodine (PVP-I) vs chlorhexidine gluconate (CHG) on CC proportions after primary breast augmentation through a periareolar approach.

METHODS: In June of 2014, The Society for Healthcare Epidemiology of America proposed to use CHG for preoperative skin preparation in the absence of alcohol-containing antiseptic agents as strategy to prevent surgical site infection. The clinical safety committee of a surgical center in Colombia decided to change PVP-I to CHG for surgical site preparation thereafter. The medical records of 63 patients who underwent to primary breast augmentation through a periareolar approach during 2014 were reviewed. In the first 6 months PVP-I was used in 32 patients, and later CHG was employed in 31 patients.

RESULTS: Pearson's chi-squared test to compare CC proportions between subgroups showed a statistically significant difference. The CC proportion was higher for patients who had antisepsis with PVP-I. CC was absent when CHG was employed.

CONCLUSIONS: CHG as preoperative skin antiseptic for primary breast augmentation surgery was more effective than PVP-I to help prevent biofilm-related CC.}, } @article {pmid30136892, year = {2018}, author = {Sorroche, F and Bogino, P and Russo, DM and Zorreguieta, A and Nievas, F and Morales, GM and Hirsch, AM and Giordano, W}, title = {Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {31}, number = {10}, pages = {1075-1082}, doi = {10.1094/MPMI-01-18-0004-R}, pmid = {30136892}, issn = {0894-0282}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/*physiology ; Mannosyltransferases/genetics/*metabolism ; Mutation ; Sinorhizobium meliloti/*genetics/*physiology ; }, abstract = {Bacterial surface molecules are crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, are also critical for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the production of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capsular polysaccharides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorhizobium meliloti by studying planktonic cell autoaggregation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a reduction in biofilm formation on abiotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell interactions in the lpsB mutant, which might account for the biofilm deficiency. However, a certain level of biofilm development was observed in the lpsB strain compared with the EPS II-defective mutant strains. Autoaggregation experiments carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the lpsB mutation and the loss of EPS II production strongly stimulated early attachment to alfalfa roots, the number of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.}, } @article {pmid30135237, year = {2018}, author = {Klauck, G and Serra, DO and Possling, A and Hengge, R}, title = {Spatial organization of different sigma factor activities and c-di-GMP signalling within the three-dimensional landscape of a bacterial biofilm.}, journal = {Open biology}, volume = {8}, number = {8}, pages = {}, pmid = {30135237}, issn = {2046-2441}, mesh = {Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli/genetics/*growth & development/metabolism ; Escherichia coli Proteins/metabolism ; Gene Expression Regulation, Bacterial ; Green Fluorescent Proteins/genetics/metabolism ; Sigma Factor/genetics/*metabolism ; Signal Transduction ; }, abstract = {Bacterial biofilms are large aggregates of cells embedded in an extracellular matrix of self-produced polymers. In macrocolony biofilms of Escherichia coli, this matrix is generated in the upper biofilm layer only and shows a surprisingly complex supracellular architecture. Stratified matrix production follows the vertical nutrient gradient and requires the stationary phase σ[S] (RpoS) subunit of RNA polymerase and the second messenger c-di-GMP. By visualizing global gene expression patterns with a newly designed fingerprint set of Gfp reporter fusions, our study reveals the spatial order of differential sigma factor activities, stringent control of ribosomal gene expression and c-di-GMP signalling in vertically cryosectioned macrocolony biofilms. Long-range physiological stratification shows a duplication of the growth-to-stationary phase pattern that integrates nutrient and oxygen gradients. In addition, distinct short-range heterogeneity occurs within specific biofilm strata and correlates with visually different zones of the refined matrix architecture. These results introduce a new conceptual framework for the control of biofilm formation and demonstrate that the intriguing extracellular matrix architecture, which determines the emergent physiological and biomechanical properties of biofilms, results from the spatial interplay of global gene regulation and microenvironmental conditions. Overall, mature bacterial macrocolony biofilms thus resemble the highly organized tissues of multicellular organisms.}, } @article {pmid30134244, year = {2019}, author = {Dostert, M and Belanger, CR and Hancock, REW}, title = {Design and Assessment of Anti-Biofilm Peptides: Steps Toward Clinical Application.}, journal = {Journal of innate immunity}, volume = {11}, number = {3}, pages = {193-204}, pmid = {30134244}, issn = {1662-8128}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Biofilms/*drug effects ; Drug Compounding ; Drug Discovery ; Humans ; Oligopeptides/pharmacology ; Peptides/*pharmacology/therapeutic use ; Quantitative Structure-Activity Relationship ; Cathelicidins ; }, abstract = {Highly antibiotic resistant, microbial communities, referred to as biofilms, cause various life-threatening infections in humans. At least two-thirds of all clinical infections are biofilm associated, and antibiotic therapy regularly fails to cure patients. Anti-biofilm peptides represent a promising approach to treat these infections by targeting biofilm-specific characteristics such as highly conserved regulatory mechanisms. They are being considered for clinical application and we discuss here key factors in discovery, design, and application, particularly the implementation of host-mimicking conditions, that are required to enable the successful advancement of potent anti-biofilm peptides from the bench to the clinic.}, } @article {pmid30131945, year = {2018}, author = {Midha, A and Janek, K and Niewienda, A and Henklein, P and Guenther, S and Serra, DO and Schlosser, J and Hengge, R and Hartmann, S}, title = {The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {271}, pmid = {30131945}, issn = {2235-2988}, mesh = {Agglutination Tests ; Animals ; Anti-Bacterial Agents/analysis/*metabolism ; *Antibiosis ; Ascaris suum/chemistry/*metabolism ; Bacteria/*drug effects/*growth & development ; Biofilms/*drug effects/*growth & development ; Gentian Violet/analysis ; Helminth Proteins/analysis/metabolism ; Mass Spectrometry ; Microbial Sensitivity Tests ; Staining and Labeling ; Swine ; }, abstract = {Ascariasis is a widespread soil-transmitted helminth infection caused by the intestinal roundworm Ascaris lumbricoides in humans, and the closely related Ascaris suum in pigs. Progress has been made in understanding interactions between helminths and host immune cells, but less is known concerning the interactions of parasitic nematodes and the host microbiota. As the host microbiota represents the direct environment for intestinal helminths and thus a considerable challenge, we studied nematode products, including excretory-secretory products (ESP) and body fluid (BF), of A. suum to determine their antimicrobial activities. Antimicrobial activities against gram-positive and gram-negative bacterial strains were assessed by the radial diffusion assay, while effects on biofilm formation were assessed using the crystal violet static biofilm and macrocolony assays. In addition, bacterial neutralizing activity was studied by an agglutination assay. ESP from different A. suum life stages (in vitro-hatched L3, lung-stage L3, L4, and adult) as well as BF from adult males were analyzed by mass spectrometry. Several proteins and peptides with known and predicted roles in nematode immune defense were detected in ESP and BF samples, including members of A. suum antibacterial factors (ASABF) and cecropin antimicrobial peptide families, glycosyl hydrolase enzymes such as lysozyme, as well as c-type lectin domain-containing proteins. Native, unconcentrated nematode products from intestine-dwelling L4-stage larvae and adults displayed broad-spectrum antibacterial activity. Additionally, adult A. suum ESP interfered with biofilm formation by Escherichia coli, and caused bacterial agglutination. These results indicate that A. suum uses a variety of factors with broad-spectrum antibacterial activity to affirm itself within its microbe-rich environment in the gut.}, } @article {pmid30131944, year = {2018}, author = {Subhadra, B and Kim, J and Kim, DH and Woo, K and Oh, MH and Choi, CH}, title = {Local Repressor AcrR Regulates AcrAB Efflux Pump Required for Biofilm Formation and Virulence in Acinetobacter nosocomialis.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {270}, pmid = {30131944}, issn = {2235-2988}, mesh = {Acinetobacter/*genetics/*growth & development ; Acinetobacter Infections/microbiology/pathology ; Animals ; Binding Sites ; Biofilms/*growth & development ; Computational Biology ; DNA, Bacterial/metabolism ; Disease Models, Animal ; Electrophoretic Mobility Shift Assay ; *Gene Expression Regulation, Bacterial ; Membrane Transport Proteins/genetics/*metabolism ; Mice ; Operon ; Promoter Regions, Genetic ; Protein Binding ; Repressor Proteins/genetics/*metabolism ; Survival Analysis ; Virulence ; }, abstract = {Multidrug efflux systems contribute to antimicrobial resistance and pathogenicity in bacteria. Here, we report the identification and characterization of a transcriptional regulator AcrR controlling the yet uncharacterized multidrug efflux pump, AcrAB in Acinetobacter nosocomialis. In silico analysis revealed that the homologs of AcrR and AcrAB are reported in the genomes of many other bacterial species. We confirmed that the genes encoding the AcrAB efflux pump, acrA and acrB forms a polycistronic operon which is under the control of acrR gene upstream of acrA. Bioinformatic analysis indicated the presence of AcrR binding motif in the promoter region of acrAB operon and the specific binding of AcrR was confirmed by electrophoretic mobility shift assay (EMSA). The EMSA data showed that AcrR binds to -89 bp upstream of the start codon of acrA. The mRNA expression analysis depicted that the expression of acrA and acrB genes are elevated in the deletion mutant compared to that in the wild type confirming that AcrR acts as a repressor of acrAB operon in A. nosocomialis. The deletion of acrR resulted in increased motility, biofilm/pellicle formation and invasion in A. nosocomialis. We further analyzed the role of AcrR in A. nosocomialis pathogenesis in vivo using murine model and it was shown that acrR mutant is highly virulent inducing severe infection in mouse leading to host death. In addition, the intracellular survival rate of acrR mutant was higher compared to that of wild type. Our data demonstrates that AcrR functions as an important regulator of AcrAB efflux pump and is associated with several phenotypes such as motility, biofilm/pellicle formation and pathogenesis in A. nosocomialis.}, } @article {pmid30131525, year = {2018}, author = {Roostaei, J and Zhang, Y and Gopalakrishnan, K and Ochocki, AJ}, title = {Mixotrophic Microalgae Biofilm: A Novel Algae Cultivation Strategy for Improved Productivity and Cost-efficiency of Biofuel Feedstock Production.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {12528}, pmid = {30131525}, issn = {2045-2322}, mesh = {Autotrophic Processes ; Biofilms/*growth & development ; Biofuels/*microbiology ; Biomass ; Hydrophobic and Hydrophilic Interactions ; Microalgae/*physiology ; Wastewater ; }, abstract = {In this work, we studied a novel algae cultivation strategy, mixotrophic microalgae biofilm, to improve the productivity and cost-efficiency of algal biofuel production. In contrast to previous methods, this improved approach can achieve high productivity at low cost by harnessing the benefits of mixotrophic growth's high efficiency, i.e., capable of subsisting on inorganic and organic carbons thus unaffected by limited light, and microalgae biofilm's low harvesting cost. Our results, as one of the first studies of this type, proved that microalgae biofilms under mixotrophic condition exhibited significantly higher productivity and quality of biofuel feedstock: 2-3 times higher of biomass yield, 2-10 times higher of lipid accumulation, and 40-60% lower of ash content when compared to microalgae biofilms under autotrophic condition. In addition, we investigated the impact of cell-surface properties (hydrophobicity and roughness) on the growth activities of microalgae biofilms and found that the productivity of mixotrophic biofilms was significantly correlated with the surface hydrophobicity. Finally, our work demonstrated the applicability of integrating this novel cultivation method with wastewater for maximum efficiency. This study opens a new possibility to solve the long-lasting challenges of algal biofuel feedstock production, i.e., low productivity and high cost of algal cultivation.}, } @article {pmid30131361, year = {2018}, author = {Szczesny, M and Beloin, C and Ghigo, JM}, title = {Increased Osmolarity in Biofilm Triggers RcsB-Dependent Lipid A Palmitoylation in Escherichia coli.}, journal = {mBio}, volume = {9}, number = {4}, pages = {}, pmid = {30131361}, issn = {2150-7511}, mesh = {Acyltransferases/genetics ; *Biofilms ; Escherichia coli/genetics/*metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Lipid A/*metabolism ; Lipopolysaccharides/metabolism ; *Lipoylation ; Osmolar Concentration ; Transcription Factors/genetics/*metabolism ; }, abstract = {Biofilms are often described as protective shelters that preserve bacteria from hostile surroundings. However, biofilm bacteria are also exposed to various stresses and need to adjust to the heterogeneous physicochemical conditions prevailing within biofilms. In Gram-negative bacteria, such adaptations can result in modifications of the lipopolysaccharide, a major component of the outer membrane characterized by a highly dynamic structure responding to environmental changes. We previously showed that Gram-negative biofilm bacteria undergo an increase in lipid A palmitoylation mediated by the PagP enzyme, contributing to increased resistance to host defenses. Here we describe a regulatory pathway leading to transcriptional induction of pagP in response to specific conditions created in the biofilm environment. We show that pagP expression is induced via the Rcs envelope stress system independently of the Rcs phosphorelay cascade and that it requires the GadE auxiliary regulator. Moreover, we identify an increase in osmolarity (i.e., ionic stress) as a signal able to induce pagP expression in an RcsB-dependent manner. Consistently, we show that the biofilm is a hyperosmolar environment and that RcsB-dependent pagP induction can be dampened in the presence of an osmoprotectant. These results provide new insights into the adaptive mechanisms of bacterial differentiation in biofilm.IMPORTANCE The development of the dense bacterial communities called biofilms creates a highly heterogeneous environment in which bacteria are subjected to a variety of physicochemical stresses. We investigated the mechanisms of a widespread and biofilm-associated chemical modification of the lipopolysaccharide (LPS), a major component of all Gram-negative bacterial outer membranes. This modification corresponds to the incorporation, mediated by the enzyme PagP, of a palmitate chain into lipid A (palmitoylation) that reduces bacterial recognition by host immune responses. Using biochemical and genetic approaches, we demonstrate that a significant part of biofilm-associated lipid A palmitoylation is triggered upon induction of pagP transcription by the hyperosmolar biofilm environment. pagP induction is regulated by RcsB, the response regulator of the Rcs stress response pathway, and is not observed under planktonic conditions. Our report provides new insights into how physiological adaptations to local biofilm microenvironments can contribute to decreases in susceptibility to antimicrobial agents and host immune defenses.}, } @article {pmid30131358, year = {2018}, author = {Uppuluri, P and Acosta Zaldívar, M and Anderson, MZ and Dunn, MJ and Berman, J and Lopez Ribot, JL and Köhler, JR}, title = {Candida albicans Dispersed Cells Are Developmentally Distinct from Biofilm and Planktonic Cells.}, journal = {mBio}, volume = {9}, number = {4}, pages = {}, pmid = {30131358}, issn = {2150-7511}, support = {R01 AI095305/AI/NIAID NIH HHS/United States ; R21 AI137716/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*cytology/genetics ; Fungal Proteins/*genetics/metabolism ; Gene Expression Profiling ; Movement ; Peptide Synthases/genetics/metabolism ; Repressor Proteins/genetics/metabolism ; Sequence Analysis, RNA ; }, abstract = {Candida albicans surface-attached biofilms such as those formed on intravenous catheters with direct access to the bloodstream often serve as a nidus for continuous release of cells capable of initiating new infectious foci. We previously reported that cells dispersed from a biofilm are yeast cells that originate from the top-most hyphal layers of the biofilm. Compared to their planktonic counterparts, these biofilm dispersal yeast cells displayed enhanced virulence-associated characteristics and drug resistance. However, little is known about their molecular properties. To address that issue, in this study we aimed to define the molecular characteristics of these biofilm dispersal cells. We found that the inducer of dispersal, PES1, genetically interacts with the repressor of filamentation, NRG1, in a manner consistent with the definition of dispersed cells as yeast cells. Further, using a flow biofilm model, we performed comprehensive comparative RNA sequencing on freshly dispersed cells in order to identify unique transcriptomic characteristics. Gene expression analysis demonstrated that dispersed cells largely inherit a biofilm-like mRNA profile. Strikingly, however, dispersed cells seemed transcriptionally reprogrammed to acquire nutrients such as zinc and amino acids and to metabolize alternative carbon sources, while their biofilm-associated parent cells did not induce the same high-affinity transporters or express gluconeogenetic genes, despite exposure to the same nutritional signals. Collectively, the findings from this study characterize cell dispersal as an intrinsic step of biofilm development which generates propagules more adept at colonizing distant host sites. This developmental step anticipates the need for virulence-associated gene expression before the cells experience the associated external signals.IMPORTANCECandida albicans surface-attached biofilms serve as a reservoir of cells to perpetuate and expand an infection; cells released from biofilms on catheters have direct access to the bloodstream. Biofilm dispersal yeast cells exhibit enhanced adhesion, invasion, and biofilm formation compared to their planktonic counterparts. Here, we show using transcriptome sequencing (RNA-seq) that dispersed yeast cells are developmentally distinct from the cells in their parent biofilms as well as from planktonic yeast cells. Dispersal cells possess an anticipatory expression pattern that primes them to infect new sites in the host, to survive in nutrient-starved niches, and to invade new sites. These studies identified dispersal cells as a unique proliferative cell type of the biofilm and showed that they could serve as targets for antibiofilm drug development in the future.}, } @article {pmid30130636, year = {2018}, author = {Liduino, VS and Lutterbach, MTS and Sérvulo, EFC}, title = {Biofilm activity on corrosion of API 5L X65 steel weld bead.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {172}, number = {}, pages = {43-50}, doi = {10.1016/j.colsurfb.2018.08.026}, pmid = {30130636}, issn = {1873-4367}, mesh = {Bacteria/metabolism ; *Biofilms ; Corrosion ; Electrochemistry ; Microscopy, Electron, Scanning ; Seawater/chemistry ; Spectrometry, X-Ray Emission ; Steel/*chemistry ; *Welding ; }, abstract = {This work aimed to identify microbial colonization and biocorrosion in welded seam areas of API 5 L X65 carbon steel, since microorganisms are ubiquitous and there is a lack of information on their biological and electrochemical interactions with these structures. In the present study, polished and unpolished welded coupons prepared by shielded metal arc welding were assayed to identify the effect of surface roughness and local changes in the metal microstructure on microbial colonization. Experiments were performed in glass cell vessels with fresh and sterile seawater to establish the presence or absence of microorganisms. For comparison, nonwelded coupons were simultaneously tested as a control. On the 15th day, both polished and unpolished welded coupons and the nonwelded coupons immersed in fresh seawater showed microbial colonization, though the corrosion products were more abundant for the welded coupons. Nevertheless, unpolished welded coupons showed a higher predominance of pitting around the beads than polished coupons. These results suggest that filler material creates conditions more favorable for biofilm development, thus intensifying the localized corrosion on the welds. It can be concluded that adhesion and subsequent biocorrosion are directly influenced by surface roughness, whereas microstructural modifications due to welding interfere little with microbial adhesion, regardless of the greater pit depths compared to those of nonwelded coupons. Additionally, although open circuit potential measurements indicated that metal surfaces are protected when coated with biofilms, pitting corrosion was more pronounced in welded coupons immersed in fresh seawater than in those immersed in seawater without microorganisms. Therefore, the use of open circuit analysis alone is not recommended for biocorrosion monitoring of welded coupons.}, } @article {pmid30130574, year = {2018}, author = {Ghorbanzadeh, A and Fekrazad, R and Bahador, A and Ayar, R and Tabatabai, S and Asefi, S}, title = {Evaluation of the antibacterial efficacy of various root canal disinfection methods against Enterococcus faecalis biofilm. An ex-vivo study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {44-51}, doi = {10.1016/j.pdpdt.2018.08.010}, pmid = {30130574}, issn = {1873-1597}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/drug effects ; Chlorhexidine/*analogs & derivatives/pharmacology ; Dental Pulp Cavity/*drug effects ; Edetic Acid/pharmacology ; Enterococcus faecalis/*drug effects ; Humans ; Indocyanine Green/*pharmacology ; Lasers, Semiconductor ; Low-Level Light Therapy/*methods ; Sodium Hypochlorite/pharmacology ; }, abstract = {BACKGROUND: Complete elimination of bacteria and their by-products from the root canal system is very difficult with current techniques. The purpose of this study was to compare the antibacterial efficacy of different disinfection protocols against Enterococcus faecalis (E. faecalis) biofilms.

METHODS: Seventy-six extracted single-rooted human teeth were selected. Root canal preparation was done by proTaper rotary instruments. The smear layer was removed by 17% EDTA, followed by 5.25% sodium hypochlorite. After sterilization using gamma irradiation, sterilized specimens were inoculated with an E. faecalis suspension, incubated for 4 days and 4 weeks and then randomly divided into two experimental groups (4 days, 4 weeks old biofilms). After the confirmation of biofilm formation with SEM, the specimens in the experimental groups were randomly divided into five experimental subgroups according to the method of disinfection applied, which included: Diode laser irradiation (810 nm, 2 W), Light activated disinfection (LAD) with Indocyanine Green, 0.2% Chlorhexidine gluconate (0.2% CHX), 0.2% CHX + LAD and 0.2% CHX + Diode groups.

RESULTS: Complete biofilm bacterial elimination was not observed in either of the experimental groups. CHX + LAD (0.2%) method exhibited the highest reduction value in biofilm and only Diode alone revealed the lowest in all the root canal portions. Disinfection protocols also showed significantly lower antibacterial efficacy against 4-week old than the 4-day old matured biofilms (P < 0.05).

CONCLUSION: All the evaluated methods in this study were effective in the relative elimination of the E. faecalis biofilms except diode laser alone. Nevertheless, 0.2% CHX + LAD exhibited significantly higher efficacy in reducing both 4-day and 4-week old biofilms.}, } @article {pmid30129268, year = {2018}, author = {Cunha, LDD and Peruzzo, DC and Costa, LA and Pereira, ALP and Benatti, BB}, title = {Effect of a single-tufted toothbrush on the control of dental biofilm in orthodontic patients: A randomized clinical trial.}, journal = {International journal of dental hygiene}, volume = {16}, number = {4}, pages = {512-518}, doi = {10.1111/idh.12360}, pmid = {30129268}, issn = {1601-5037}, support = {01249/13//FAPEMA/ ; BEPP-01594/12//FAPEMA/ ; }, mesh = {Adult ; Biofilms/*growth & development ; Dental Plaque Index ; Female ; Humans ; Male ; Oral Hygiene/*instrumentation ; Orthodontic Appliances/*microbiology ; Periodontal Index ; Prospective Studies ; Statistics, Nonparametric ; Time Factors ; Toothbrushing/*instrumentation ; Young Adult ; }, abstract = {OBJECTIVE: To compare the effect of a single-tufted toothbrush combined or not with a conventional toothbrush to control dental biofilm in healthy orthodontic patients.

MATERIALS AND METHODS: Twenty orthodontic patients were randomly assigned to receive three different treatments: Group 1-conventional toothbrush; Group 2-single-tufted toothbrush and Group 3-combination of single-tufted and conventional toothbrushes. Stained plaque index (SPI), visible plaque index (VPI) and gingival bleeding index (GBI) were recorded. The data were analysed by Kolmogorov-Smirnov test. Wilcoxon test was used for intragroup comparison and Friedman test for the intergroup comparison (α = 5%).

RESULTS: Intragroup analysis showed that VPI and SPI significantly decreased (P < 0.05) after 72 hour in Group 3. Anterior and posterior teeth did not show any significant statistical differences after 72 hour (P > 0.05), but VPI values in the labial surfaces were different to Group 3 (P < 0.05) in comparison with the other groups after 72 hour. Group 3 showed a statistically significant reduction (P < 0.05) for SPI in the interproximal surfaces when compared with Group 1.

CONCLUSION: The combination of single-tufted and conventional toothbrushes was effective for controlling dental biofilm formation in orthodontic patients.}, } @article {pmid30128583, year = {2018}, author = {Liu, Y and Shi, H and Wang, Z and Huang, X and Zhang, X}, title = {Pleiotropic control of antibiotic biosynthesis, flagellar operon expression, biofilm formation, and carbon source utilization by RpoN in Pseudomonas protegens H78.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {22}, pages = {9719-9730}, doi = {10.1007/s00253-018-9282-0}, pmid = {30128583}, issn = {1432-0614}, support = {31470196//National Natural Science Foundation of China/ ; 31270083//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*biosynthesis ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Carbon/*metabolism ; Fimbriae, Bacterial/metabolism ; *Gene Expression Regulation, Bacterial ; *Operon ; Pseudomonas/genetics/*physiology ; RNA Polymerase Sigma 54/genetics/*metabolism ; }, abstract = {The rhizobacterium Pseudomonas protegens H78 biosynthesizes a number of antibiotic compounds, including pyoluteorin, 2,4-diacetylphloroglucinol, and pyrrolnitrin. Here, we investigated the global regulatory function of the nitrogen metabolism-related sigma factor RpoN in P. protegens H78 through RNA-seq and phenotypic analysis. During the mid- to late-log growth phase, transcriptomic profiling revealed that 562 genes were significantly upregulated, and 502 genes were downregulated by at least twofold at the RNA level in the rpoN deletion mutant in comparison with the wild-type strain H78. With respect to antibiotics, Plt biosynthesis and the expression of its operon were positively regulated, while Prn biosynthesis and the expression of its operon were negatively regulated by RpoN. RpoN is responsible for the global activation of operons involved in flagellar biogenesis and assembly, biofilm formation, and bacterial mobility. In contrast, RpoN was shown to negatively control a number of secretion system operons including one type VI secretion system operon (H1-T6SS), two pilus biogenesis operons (Flp/Tad-T4b pili and Csu-T1 pili), and one polysaccharide biosynthetic operon (psl). In addition, two operons that are involved in mannitol and inositol utilization are under the positive regulation of RpoN. Consistent with this result, the ability of H78 to utilize mannitol or inositol as a sole carbon source is positively influenced by RpoN. Taken together, the RpoN-mediated global regulation is mainly involved in flagellar biogenesis and assembly, bacterial mobility, biofilm formation, antibiotic biosynthesis, secretion systems, and carbon utilization in P. protegens H78.}, } @article {pmid30128582, year = {2018}, author = {Ontiveros-Valencia, A and Zhou, C and Zhao, HP and Krajmalnik-Brown, R and Tang, Y and Rittmann, BE}, title = {Managing microbial communities in membrane biofilm reactors.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {21}, pages = {9003-9014}, doi = {10.1007/s00253-018-9293-x}, pmid = {30128582}, issn = {1432-0614}, mesh = {Animals ; Bacteria/*growth & development ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Humans ; Hydrogen/metabolism ; Membranes/*microbiology ; Methane/metabolism ; Oxygen/metabolism ; }, abstract = {Membrane biofilm reactors (MBfRs) deliver gaseous substrates to biofilms that develop on the outside of gas-transfer membranes. When an MBfR delivers electron donors hydrogen (H2) or methane (CH4), a wide range of oxidized contaminants can be reduced as electron acceptors, e.g., nitrate, perchlorate, selenate, and trichloroethene. When O2 is delivered as an electron acceptor, reduced contaminants can be oxidized, e.g., benzene, toluene, and surfactants. The MBfR's biofilm often harbors a complex microbial community; failure to control the growth of undesirable microorganisms can result in poor performance. Fortunately, the community's structure and function can be managed using a set of design and operation features as follows: gas pressure, membrane type, and surface loadings. Proper selection of these features ensures that the best microbial community is selected and sustained. Successful design and operation of an MBfR depends on a holistic understanding of the microbial community's structure and function. This involves integrating performance data with omics results, such as with stoichiometric and kinetic modeling.}, } @article {pmid30128579, year = {2018}, author = {Zhou, JW and Hou, B and Liu, GY and Jiang, H and Sun, B and Wang, ZN and Shi, RF and Xu, Y and Wang, R and Jia, AQ}, title = {Attenuation of Pseudomonas aeruginosa biofilm by hordenine: a combinatorial study with aminoglycoside antibiotics.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {22}, pages = {9745-9758}, doi = {10.1007/s00253-018-9315-8}, pmid = {30128579}, issn = {1432-0614}, support = {2017YFD0201401//the National Key Research and Development Program of China/ ; 41766006//National Natural Science Foundation of China/ ; BK20170859//Natural Science Foundation of Jiangsu Province/ ; 201608052//Science and Technology Development Program of Modern Agriculture/ ; 30916011307//Six Talent Peaks Project in Jiangsu Province, and Fundamental Research Funds for the Central Universities/ ; }, mesh = {Aminoglycosides/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects ; Tyramine/*analogs & derivatives/pharmacology ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous pathogen that is the leading cause of chronic infections. Bacterial biofilm formation facilitates CF development and restricts the anti-bacterial potential of many current antibiotics. The capacity of P. aeruginosa to form biofilms and resist antibiotics is closely correlated with quorum sensing (QS). Disrupting QS by QS inhibitors is a promising strategy for treating chronic infections. Here, we evaluated the effect of hordenine, a recently characterized QS inhibitor, on the susceptibility of aminoglycoside antibiotics against P. aeruginosa biofilms. Hordenine significantly enhanced the susceptibility of aminoglycoside antibiotics tobramycin, gentamycin, and amikacin against P. aeruginosa PAO1 biofilm formation. Combinations of hordenine and aminoglycoside antibiotics showed potent efficiency in disrupting the preformed biofilms of P. aeruginosa. Microscopic observations showed flat, scattered, and unstructured biofilm architecture after treatment with hordenine. Mechanistic study further revealed that hordenine treatment led to the downregulation of genes involved in QS and biofilm formation. Thus, our results suggest that hordenine has the potential to function as an antibiotic accelerant in treating P. aeruginosa infections.}, } @article {pmid30126038, year = {2018}, author = {Korsch, M and Marten, SM and Walther, W and Vital, M and Pieper, DH and Dötsch, A}, title = {Impact of dental cement on the peri-implant biofilm-microbial comparison of two different cements in an in vivo observational study.}, journal = {Clinical implant dentistry and related research}, volume = {20}, number = {5}, pages = {806-813}, doi = {10.1111/cid.12650}, pmid = {30126038}, issn = {1708-8208}, mesh = {Adult ; Aged ; Biofilms/*growth & development ; Dental Cements/adverse effects/*therapeutic use ; Dental Implants/adverse effects/*microbiology ; Dental Prosthesis, Implant-Supported/adverse effects/methods ; Dental Restoration, Permanent/adverse effects/methods ; Eugenol/adverse effects/therapeutic use ; Female ; Humans ; Male ; Middle Aged ; Peri-Implantitis/*etiology ; Young Adult ; Zinc Oxide/adverse effects/therapeutic use ; }, abstract = {BACKGROUND: The type of cement used in cemented fixed implant-supported restorations influences formation of undetected excess cement and composition of the peri-implant biofilm. Excess cement and dysbiosis of the biofilm involve the risk of peri-implant inflammation.

PURPOSE: The aim of the study was to investigate the impact of two different cements on the peri-implant biofilm and inflammation.

MATERIALS AND METHODS: In an observational study, the suprastructures of 34 patients with cemented fixed implant-supported restorations were revised. In 20 patients, a methacrylate cement (Premier Implant cement [PIC]) and in 14 patients, a zinc oxide eugenol cement (Temp Bond [TB]) were used. After revision, TB was used for recementation. During revision and follow-up after 1 year, microbial samples were obtained.

RESULTS: Excess cement was found in 12 (60%) of the 20 patients with PIC. Suppuration was observed in two (25%) implants with PIC without excess cement (PIC-) and in all 12 (100%) implants with PIC and excess cement (PIC+). Implants cemented with TB had neither excess cement nor suppuration. The taxonomic analysis of the microbial samples revealed an accumulation of periodontal pathogens in the PIC patients independent of the presence of excess cement. Significantly, fewer oral pathogens occurred in patients with TB compared to patients with PIC. TB was used in all cases (PIC and TB) for recementation. In the follow-up check, suppuration was not found around any of the implants with PIC-, only around one implant with PIC+ and around one implant with TB. Bacterial species associated with severe periodontal infections that were abundant in PIC- and PIC+ samples before the revision were reduced after 1 year to levels found in the TB samples.

CONCLUSIONS: The revision and recementation with TB had a positive effect on the peri-implant biofilm in cases with PIC. The cementation of suprastructures on implants with TB is an alternative method to be considered.}, } @article {pmid30124817, year = {2018}, author = {Cirri, E and Vyverman, W and Pohnert, G}, title = {Biofilm interactions-bacteria modulate sexual reproduction success of the diatom Seminavis robusta.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {11}, pages = {}, doi = {10.1093/femsec/fiy161}, pmid = {30124817}, issn = {1574-6941}, mesh = {Bacteria/metabolism ; *Bacterial Physiological Phenomena ; *Biofilms ; Diatoms/metabolism/*physiology ; Pheromones/metabolism ; Reproduction ; Species Specificity ; }, abstract = {Marine biofilms are complex multi-species communities where chemical signaling regulates a substantial share of interactions. The involved natural products represent targets for competition strategies by signal interference. Diatoms, that often dominate biofilms, rely on a complex pheromone system during sexual reproduction, involving synchronizing and attracting metabolites. The present study addresses the effect of bacteria on sexual reproduction of the model pennate diatom Seminavis robusta. We observe that sexual reproduction is most efficient under axenic conditions. Bacteria isolated from field collected biofilms modulate sexual reproduction in the algae. A species-specific effect on the diatom mating efficiency could be observed, with Maribactersp. and Marinobactersp. significantly reducing the sexual reproduction rate. Spent medium from these bacteria has the same effect, demonstrating that chemically mediated cross kingdom interactions take place. In contrast, proportion of auxospores. We further observed a lower concentration of the diatom attraction pheromone diproline in the presence of bacteria compared to axenic conditions. In agreement, the Seminavis-associated bacterial community as well as isolated bacterial strains degraded the pheromone over time. Our results highlight that the pheromone system of diatoms is subject to interference strategies of the associated bacterial community by modulation of the signal landscape.}, } @article {pmid30124812, year = {2018}, author = {Kavazos, CRJ and Huggett, MJ and Mueller, U and Horwitz, P}, title = {Bacterial and ciliate biofilm community structure at different spatial levels of a salt lake meta-community.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {10}, pages = {}, doi = {10.1093/femsec/fiy148}, pmid = {30124812}, issn = {1574-6941}, mesh = {Bacteria/*classification/genetics/growth & development ; Biodiversity ; Biofilms/*classification/growth & development ; Ciliophora/*classification/genetics/growth & development ; Lakes/chemistry/*microbiology ; Plankton ; Salinity ; Water Microbiology ; }, abstract = {Meta-communities are assembled along an ecological scale that determines local and regional diversity. Spatial patterns have been detected in planktonic bacterial communities at distances <20 m, but little is known about the occurrence of similar variation for other microbial groups and changes in microbial meta-community assembly at different levels of a meta-community. To examine this variation, the biofilm of eight saline ponds were used to investigate processes shaping diversity within ponds (β) and between ponds (δ). Bacterial and ciliate communities were assessed using ARISA and T-RFLP respectively, while diversity partitioning methods were used to examine the importance of taxonomic turnover and variation partitioning was used to distinguish spatial from environmental determinants. The results show that turnover is important for determining β- and δ-diversity of biofilms. Spatial factors are important drivers of bacterial β-diversity but were unimportant for ciliate β-diversity. Environmental variation was a strong determinant of bacterial and ciliate δ-diversity, suggesting sorting processes are important for assembling pond communities. Determinants of diversity in bacteria are not universal for ciliates, suggesting higher functional redundancy of bacteria or the greater niche breadth of ciliates may be important in discriminating assembly processes between the two organisms.}, } @article {pmid30120959, year = {2019}, author = {Bhatt, S and Mehta, P and Chen, C and Schneider, CL and White, LN and Chen, HL and Kong, MG}, title = {Efficacy of low-temperature plasma-activated gas disinfection against biofilm on contaminated GI endoscope channels.}, journal = {Gastrointestinal endoscopy}, volume = {89}, number = {1}, pages = {105-114}, doi = {10.1016/j.gie.2018.08.009}, pmid = {30120959}, issn = {1097-6779}, mesh = {Argon/*pharmacology ; Biofilms/*drug effects ; Disinfection/methods ; Electron Spin Resonance Spectroscopy ; Endoscopes, Gastrointestinal/*microbiology ; *Equipment Contamination ; Escherichia coli/*drug effects/ultrastructure ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/ultrastructure ; Microscopy, Electron, Scanning ; Pseudomonas aeruginosa/*drug effects/ultrastructure ; Reactive Nitrogen Species/metabolism ; Reactive Oxygen Species/metabolism ; }, abstract = {BACKGROUND AND AIMS: It has been increasingly recognized that the safety of GI endoscopes needs to be improved by addressing the small margin of safety of high-level disinfectants (HLDs) and the failure of HLDs to clear multidrug-resistant organisms and biofilms. There is also an unmet need for effective low-temperature sterilization techniques that have a clear pathway for U.S. Food and Drug Administration clearance. Here, we report the results of our investigation of a novel argon plasma-activated gas (PAG) for disinfection and potentially sterilization of biofilm-contaminated endoscopic channels.

METHODS: Test polytetrafluoroethylene channel segments were contaminated with 4-, 24- and 48-hour luminal biofilms of methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, or Escherichia coli and were treated by PAG flowing for up to 9 minutes. After PAG treatment, inactivation and dispersal of luminal bacterial biofilms and their regrowth in 48 hours were evaluated. Reactive species induced by PAG were measured with colorimetric probes and electron spin resonance spectrometry. Surface morphology and elemental composition of PAG-treated channel material were analyzed with scanning electron microscopy.

RESULTS: PAG treatment for 9 minutes led to more than 8 log reduction of viable cells and dispersal of 24- and 48-hour luminal biofilms of all 3 bacteria and to suppression of their regrowth, whereas it resulted in little morphologic abnormalities in channel material. Ozone concentration of PAG fell to below .01 ppm within 30 seconds of switching off the plasma. PAG-treated deionized water was acidified with numerous types of reactive species, each with a concentration some 3 orders of magnitude or more below its bacterial inhibition concentration.

CONCLUSIONS: PAG is capable of effectively and rapidly disinfecting luminal bacterial biofilms and offers an alternative to the step of HLDs and/or ethylene oxide in the endoscope reprocessing procedure with safety to personnel and environment.}, } @article {pmid30119039, year = {2018}, author = {Ismail, Z and Aziz, MMA and Mahmood, NAN and Ismail, S and Umor, NA and Faua'ad Syed Muhammad, SA}, title = {Optimisation of a modified submerged bed biofilm reactor for biological oleochemical wastewater treatment.}, journal = {Journal of environmental management}, volume = {226}, number = {}, pages = {156-162}, doi = {10.1016/j.jenvman.2018.08.003}, pmid = {30119039}, issn = {1095-8630}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Oleochemicals industry effluence mainly contains a high chemical oxygen demand (COD) in a range of 6000-20,000 ppm. An effective biological wastewater treatment process must be carried out before wastewater is discharged into the environment. In this study, a submerged bed biofilm reactor (SBBR) was adapted to the biological oleochemical wastewater treatment plant observed in the present study. The effect of wastewater flow rate (100-300 mL/min), Cosmoball[®] percentage in the SBBR system (25-75%), and percentage of activated sludge (0-50%) were investigated in terms of COD reduction. The Box-Behnken design was used for response surface methodology (RSM) and to create a set of 18 experimental runs, which was needed for optimising the biological oleochemical wastewater treatment. A quadratic polynomial model with estimated coefficients was developed to describe COD reduction patterns. The analysis of variance (ANOVA) shows that the wastewater flow rate was the most effective factor in reducing COD, followed by activated sludge percentage and Cosmoball[®] carrier percentage. Under the optimum conditions (i.e., a wastewater flow rate of 103.25 mL/min a Cosmoball[®] carrier percentage of 71.94%, and an activated sludge percentage of 40.50%) a COD reduction of 98% was achieved. Thus, under optimum conditions, as suggested by the BBD, SBBR systems can be used as a viable means of biological wastewater treatment in the oleochemicals industry.}, } @article {pmid30118807, year = {2018}, author = {Tavafi, H and Ali, AA and Ghadam, P and Gharavi, S}, title = {Screening, cloning and expression of a novel alginate lyase gene from P. aeruginosa TAG 48 and its antibiofilm effects on P. aeruginosa biofilm.}, journal = {Microbial pathogenesis}, volume = {124}, number = {}, pages = {356-364}, doi = {10.1016/j.micpath.2018.08.018}, pmid = {30118807}, issn = {1096-1208}, mesh = {Alginates/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/chemistry/genetics/*metabolism ; Ciprofloxacin/pharmacology ; *Cloning, Molecular ; Humans ; Microbial Sensitivity Tests ; Polysaccharide-Lyases/chemistry/genetics/*metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/chemistry/drug effects/*enzymology/genetics ; Substrate Specificity ; Tobramycin/pharmacology ; Virulence Factors/chemistry/genetics/metabolism ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen and utilizes several virulence factors for pathogenesis. One of the most important factors is alginate, found in the biofilm which enables P. aeruginosa to establish chronic lung infections.

MATERIALS AND METHODS: In this study, 25 clinical alginate-degrading isolates were selected. Biochemical and molecular approach were carried out to identify the isolates by 16S rDNA gene amplification. Growth conditions and enzyme production were the criteria for selection. Since the main objective of the project was the production and characterization of alginate lyase and its effect on biofilm elimination, the P. aeruginosa sp.TAG48 alginate lyase-encoding gene was isolated, cloned, sequenced and expressed in E.coli DH5α. The resultant enzyme was purified by affinity chromatography. Ciprofloxacin, tobramycin and cefixime were also used to test the effectiveness of these antibiotics on P. aeruginosa biofilm by minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC). The synergistic effects of these antibiotics and the recombinant alginate lyase on biofilm were evaluated.

RESULTS: Results indicate that the addition of alginate (0.2%-0.8%) and NaCl (0.2-0.5 M) to the medium significantly increases cell growth followed by higher enzyme production (p≤ 0.05). Moreover, substrate specificity of alginate lyase produced by P. aeruginosa sp.TAG48 shows the enzyme is capable of degrading both polyM and polyG alginate and acts bifunctionally. Results from the antimicrobial characteristics of the antibiotics and the enzyme have shown MBIC for ciprofloxacin, tobramycin, cefixime and enzyme in the following concentrations 4, 32, 256 and 18.75 μg/ml, and MBEC: 32, 128, ≥ 512 and 37.5 μg/ml, respectively. The study of synergism between the antibiotics and the enzyme to prevent growth and eradication of P. aeruginosa sp.TAG48 biofilm shows that alginate lyase exhibits synergy with tobramycin and cefixime but not with ciprofloxacin.

CONCLUSION: The results indicate that the use of purified novel alginate lyase with antibiotics could be a beneficial alternative for the treatment of P. aeruginosa infections. Elucidation of mechanisms involved in antibiotic resistance and the role of biofilm structure could assist physicians select optimum treatment regimen.}, } @article {pmid30118805, year = {2018}, author = {Sun, X and Lin, ZW and Hu, XX and Yao, WM and Bai, B and Wang, HY and Li, DY and Chen, Z and Cheng, H and Pan, WG and Deng, MG and Xu, GJ and Tu, HP and Chen, JW and Deng, QW and Yu, ZJ and Zheng, JX}, title = {Biofilm formation in erythromycin-resistant Staphylococcus aureus and the relationship with antimicrobial susceptibility and molecular characteristics.}, journal = {Microbial pathogenesis}, volume = {124}, number = {}, pages = {47-53}, doi = {10.1016/j.micpath.2018.08.021}, pmid = {30118805}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; China ; Disk Diffusion Antimicrobial Tests ; *Drug Resistance, Bacterial ; Erythromycin/*pharmacology ; Genes, Essential ; *Genotype ; Hospitals, University ; Humans ; Multilocus Sequence Typing ; Polymerase Chain Reaction ; Retrospective Studies ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/genetics/isolation & purification/*physiology ; Transcriptional Activation/drug effects ; tRNA Methyltransferases/genetics ; }, abstract = {PURPOSE: In this study, we aimed to investigate biofilm formation characteristics in clinical Staphylococcus aureus (S. aureus) isolates with erythromycin (ERY) resistance from China and further analyze their correlations with antimicrobial susceptibility and molecular characteristics.

METHODOLOGY: A total of 276 clinical isolates of ERY-resistant S. aureus, including 142 methicillin-resistant S. aureus (MRSA) strains and 134 methicillin-susceptible S. aureus (MSSA) strains, were retrospectively collected in China. Biofilms were determined by crystal violet staining and ERY resistance genes (ermA, ermB and ermC) were detected by polymerase chain reaction. Inducible clindamycin resistance was examined by D test and multilocus sequence typing, and clonal complexes (CCs) based on housekeeping genes were further determined.

RESULTS: The frequency of biofilm formation among ERY-resistant S. aureus was 40.9% (113/276) in total and no significant difference was found for the frequency of biofilm formation between ERY-resistant MRSA and ERY-resistant MSSA (44.4% vs 37.3%, P > 0.05). In ERY-resistant MRSA isolates, the frequency of biofilm formation in ermA-positive, gentamicin-resistant and ciprofloxacin-resistant isolates was higher than that in ermA-negative, gentamicin-sensitive and ciprofloxacin-sensitive isolates, respectively (63.9% vs 23.6%, P < 0.01; 60.3% vs 27.5%, P < 0.01; 65.2% vs 26.3%, P < 0.01). In addition, tetracycline resistance facilitated biofilm formation in both ERY-resistant MRSA and MSSA and the frequency of biofilm formation in CC239- or CC7S. aureus isolates with ERY resistance was significantly higher compared with that in CC59S. aureus (both P < 0.01).

CONCLUSION: The ermA gene, and gentamicin, ciprofloxacin and tetracycline resistance facilitate biofilm formation in ERY-resistant MRSA isolates and, moreover, ERY-resistant S. aureus isolates with positive biofilm formation exhibited clonality clustering regarding CC239 and CC7.}, } @article {pmid30116222, year = {2018}, author = {Servetas, SL and Doster, RS and Kim, A and Windham, IH and Cha, JH and Gaddy, JA and Merrell, DS}, title = {ArsRS-Dependent Regulation of homB Contributes to Helicobacter pylori Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1497}, pmid = {30116222}, issn = {1664-302X}, support = {R21 AI121517/AI/NIAID NIH HHS/United States ; }, abstract = {One elusive area in the Helicobacter pylori field is an understanding of why some infections result in gastric cancer, yet others persist asymptomatically for the life-span of the individual. Even before the genomic era, the high level of intraspecies diversity of H. pylori was well recognized and became an intriguing area of investigation with respect to disease progression. Of interest in this regard is the unique repertoire of over 60 outer membrane proteins (OMPs), several of which have been associated with disease outcome. Of these OMPs, the association between HomB and disease outcome varies based on the population being studied. While the molecular roles for some of the disease-associated OMPs have been evaluated, little is known about the role that HomB plays in the H. pylori lifecycle. Thus, herein we investigated homB expression, regulation, and contribution to biofilm formation. We found that in H. pylori strain G27, homB was expressed at a relatively low level until stationary phase. Furthermore, homB expression was suppressed at low pH in an ArsRS-dependent manner; mutation of arsRS resulted in increased homB transcript at all tested time-points. ArsRS regulation of homB appeared to be direct as purified ArsR was able to specifically bind to the homB promoter. This regulation, combined with our previous finding that ArsRS mutations lead to enhanced biofilm formation, led us to test the hypothesis that homB contributes to biofilm formation by H. pylori. Indeed, subsequent biofilm analysis using a crystal-violet quantification assay and scanning electron microscopy (SEM) revealed that loss of homB from hyper-biofilm forming strains resulted in reversion to a biofilm phenotype that mimicked wild-type. Furthermore, expression of homB in trans from a promoter that negated ArsRS regulation led to enhanced biofilm formation even in strains in which the chromosomal copy of homB had been deleted. Thus, homB is necessary for hyper-biofilm formation of ArsRS mutant strains and aberrant regulation of this gene is sufficient to induce a hyper-biofilm phenotype. In summary, these data suggest that the ArsRS-dependent regulation of OMPs such as HomB may be one mechanism by which ArsRS dictates biofilm development in a pH responsive manner.}, } @article {pmid30116152, year = {2018}, author = {Tan, Q and Ai, Q and Xu, Q and Li, F and Yu, J}, title = {Polymorphonuclear Leukocytes or Hydrogen Peroxide Enhance Biofilm Development of Mucoid Pseudomonas aeruginosa.}, journal = {Mediators of inflammation}, volume = {2018}, number = {}, pages = {8151362}, pmid = {30116152}, issn = {1466-1861}, mesh = {Alginates/chemistry ; Bacterial Adhesion ; *Biofilms ; Cell Adhesion ; Cystic Fibrosis/metabolism ; Humans ; Hydrogen Peroxide/*pharmacology ; Lung/metabolism ; Microscopy, Confocal ; Neutrophils/*cytology/microbiology ; Oxidative Stress ; Pseudomonas aeruginosa/*growth & development ; Reactive Oxygen Species/metabolism ; Respiratory Burst ; Sputum/microbiology ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogenic bacterium involved in many human infections, including pneumonia, diabetic foot ulcers, and ventilator-associated pneumonia. P. aeruginosa cells usually undergo mucoid conversion during chronic lung infection in patients with cystic fibrosis (CF) and resist destruction by polymorphonuclear leukocytes (PMNs), which release free oxygen radicals (ROS), such as H2O2. PMNs are the main leucocytes in the CF sputum of patients who are infected with P. aeruginosa, which usually forms biofilms. Here, we report that PMNs or H2O2 can promote biofilm formation by mucoid P. aeruginosa FRD1 with the use of the hanging-peg method. The mucoid strain infecting CF patients overproduces alginate. In this study, PMNs and H2O2 promoted alginate production, and biofilms treated with PMNs or H2O2 exhibited higher expression of alginate genes. Additionally, PMNs increased the activity of GDP-mannose dehydrogenase, which is the key enzyme in alginate biosynthesis. Our results demonstrate that PMNs or H2O2 can enhance mucoid P. aeruginosa biofilms.}, } @article {pmid30116127, year = {2018}, author = {Bayazian, G and Sayyahfar, S and Safdarian, M and Kalantari, F}, title = {Is there any association between adenoid biofilm and upper airway infections in pediatric patients?.}, journal = {Turk pediatri arsivi}, volume = {53}, number = {2}, pages = {71-77}, pmid = {30116127}, issn = {1306-0015}, abstract = {AIM: To evaluate the association of the presence and extent of adenoid biofilms and the frequency of upper airway infections in children with upper airway obstruction.

MATERIAL AND METHODS: This cross-sectional study was conducted from October 2014 to December 2015 on pediatric patients who were candidates for adenoidectomy due to obstructive sleep apnea. After removal of the adenoid tissue and fixation in 2.5% glutaraldehyde, the samples were sent to the electron microscopy unit. The extent of biofilm formation was examined using environmental scanning electron microscopy. These results were then confirmed using image analysis software.

RESULTS: Fifty-seven children with a mean age of 7.31 (±2.65) years were included in the study. Forty-three (75.4%) were male and 14 (24.6%) were female. The average number of upper airway infections during the last 12 months before adenoidectomy was 10.01 (±5.38). Biofilm structures were detected in all (100%) samples. As the main outcome, the extent of biofilm grading exhibited a statistically significant correlation with the frequency of upper airway infections (p<0.001). There was no significant correlation between sex and adenoid size with the biofilm extent.

CONCLUSION: The present study showed that the extent of adenoid biofilm had a significant relationship with the frequency of upper airway infection rate. It seems that the presence of a biofilm on the adenoid surface as a reservoir for microorganisms could cause chronic inflammation.}, } @article {pmid30114632, year = {2018}, author = {Asri, M and El Ghachtouli, N and Elabed, S and Ibnsouda Koraichi, S and Elabed, A and Silva, B and Tavares, T}, title = {Wicherhamomyces anomalus biofilm supported on wood husk for chromium wastewater treatment.}, journal = {Journal of hazardous materials}, volume = {359}, number = {}, pages = {554-562}, doi = {10.1016/j.jhazmat.2018.05.050}, pmid = {30114632}, issn = {1873-3336}, mesh = {Adsorption ; *Biofilms ; Chromium/*chemistry ; Extracellular Polymeric Substance Matrix/metabolism ; Saccharomycetales/*chemistry/physiology ; Waste Disposal, Fluid/methods ; Wastewater/chemistry ; Water Pollutants, Chemical/*chemistry ; Wood/*chemistry ; }, abstract = {A Wickeramomyces anomalus biofilm supported on wood husk was used to remediate water bodies contaminated with chromium (Cr), in batch and open systems. The favorable adhesion ability of the chromium-resistant yeast strain on the wood husk was predicted by XDLVO theory and confirmed by environmental scanning electronic microscopy. The chromium decontamination was then optimized in a batch mode using a central composite design (CCD). Analysis of variance (ANOVA) showed a high coefficient of determination (R[2]) value of 0.93-0.91 for Cr(VI) and total Cr removal, respectively, ensuring a satisfactory fitting of the second-order regression model to the experimental data. In batch system, the concentration of biomass exhibited the minimal effect on the process. An acidic pH of 3.72 and 5.48, an initial chromium concentration of 10 and 16.91 mg/L and a support dose of 6.95 and 8.20 g/L were optimal for Cr(VI) and total Cr removal, respectively. The breakthrough curves were determined in open system for different initial chromium concentrations. The study of glucose concentration effect on the yeast extracellular polymeric substances (EPS) production showed that a medium exempt of glucose allowed maximal EPS production and minimal chromium removal efficiency, while 20 g/L glucose concentration of presented the optimal condition for chromium removal.}, } @article {pmid30111629, year = {2018}, author = {Kiedrowski, MR and Gaston, JR and Kocak, BR and Coburn, SL and Lee, S and Pilewski, JM and Myerburg, MM and Bomberger, JM}, title = {Staphylococcus aureus Biofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection.}, journal = {mSphere}, volume = {3}, number = {4}, pages = {}, pmid = {30111629}, issn = {2379-5042}, support = {R01 HL123771/HL/NHLBI NIH HHS/United States ; R61 HL137077/HL/NHLBI NIH HHS/United States ; T32 AI049820/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cell Culture Techniques ; Coinfection/microbiology ; Culture Media, Conditioned ; Cystic Fibrosis/*complications ; Epithelial Cells/*microbiology ; Host-Pathogen Interactions ; Humans ; Models, Biological ; Respiratory Syncytial Virus Infections/*complications ; Staphylococcal Infections/*complications/*microbiology ; Staphylococcus aureus/*growth & development ; }, abstract = {Staphylococcus aureus is a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed that Pseudomonas aeruginosa exhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate if S. aureus biofilm growth in the CF airways is impacted by virus coinfection, we evaluated S. aureus growth on CF AECs. Initial studies showed an increase in S. aureus growth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed with S. aureus CF clinical isolates. Apical conditioned medium from RSV-infected cells promoted S. aureus biofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefits S. aureus biofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterized S. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions of S. aureus and RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation of S. aureus genes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection.IMPORTANCE The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.}, } @article {pmid30111175, year = {2019}, author = {Wu, Y and Shi, YG and Zeng, LY and Pan, Y and Huang, XY and Bian, LQ and Zhu, YJ and Zhang, RR and Zhang, J}, title = {Evaluation of antibacterial and anti-biofilm properties of kojic acid against five food-related bacteria and related subcellular mechanisms of bacterial inactivation.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {25}, number = {1}, pages = {3-15}, doi = {10.1177/1082013218793075}, pmid = {30111175}, issn = {1532-1738}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacillus subtilis/drug effects/genetics ; Biofilms/*drug effects ; DNA, Bacterial/isolation & purification ; Escherichia coli/drug effects/genetics ; Food Contamination/prevention & control ; *Food Microbiology ; Genome, Bacterial ; Listeria monocytogenes/drug effects/genetics ; Microbial Sensitivity Tests ; Pyrones/*pharmacology ; Salmonella typhimurium/drug effects/genetics ; Staphylococcus aureus/drug effects/genetics ; }, abstract = {Although the antimicrobial properties of kojic acid have been recognized, the subcellular mechanism of bacterial inactivation caused by it has never been clearly elucidated. In the present study, the antibacterial and anti-biofilm activity of kojic acid was evaluated against five foodborne pathogens including Listeria monocytogenes, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium. The antibacterial activity was determined by minimum inhibitory concentration, minimum bactericidal concentration, and the time-kill assay. Among them, the susceptibility of Escherichia coli was significant with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 10 and 20 mM, respectively. Subcellular mechanism of bacterial inactivation related to kojic acid was revealed through comprehensive factors including cell morphology, membrane permeability, K[+] leakage, zeta potential, intracellular enzyme, and DNA assay. Results demonstrated that bacterial inactivation caused by kojic acid, especially for Gram-negative bacteria, was primarily induced by the pronounced damage to the cell membrane integrity. Leakage of intracellular enzyme to the supernatants implied that the cell membrane permeability was compromised. Consequently, the release of K[+] from the cytosol leads to the alterations of the zeta potential of cells, which would disturb the subcellular localization of some proteins and thereby cause the bacterial inactivation. The free -CH2OH group at the C-2 of kojic acid could play more significant role in the antimicrobial performance of kojic acid against Gram-negative bacteria. Moreover, remarkable interaction with DNA was also observed. Kojic acid at sub-minimum inhibitory concentration inhibited biofilm formation by these bacteria.}, } @article {pmid30109972, year = {2018}, author = {Luque-Sastre, L and Fox, EM and Jordan, K and Fanning, S}, title = {A Comparative Study of the Susceptibility of Listeria Species to Sanitizer Treatments When Grown under Planktonic and Biofilm Conditions.}, journal = {Journal of food protection}, volume = {81}, number = {9}, pages = {1481-1490}, doi = {10.4315/0362-028X.JFP-17-466}, pmid = {30109972}, issn = {1944-9097}, mesh = {Biofilms/drug effects/*growth & development ; *Disinfectants/pharmacology ; Food Contamination/prevention & control ; *Listeria/physiology ; Plankton/drug effects/growth & development ; }, abstract = {Listeria species are ubiquitous in nature and can adapt to survive in a variety of niches, including food processing environments. Listeria species that colonize these environments may also have the potential to persist. Food safety strategies designed to manage these niches include regular cleaning and disinfection with proven sanitizers containing biocide-active compounds. Typically, these sanitizers are effective against bacteria growing under planktonic conditions, but their efficacy may be compromised when bacteria are contained in biofilms. The susceptibility of persistent Listeria isolates, i.e., those capable of forming biofilms, to a selection of sanitizers was investigated. A quaternary ammonium compound-based sanitizer was the biocide most effective against planktonic bacteria, with a MIC of 0.0015 to 0.006%. In contrast, ethanol-based sanitizers were the least effective. Although, no triclosan tolerance was observed for planktonic Listeria isolates, triclosan was the only biocide that resulted in a significant biomass reduction. Differences between Listeria species were observed; L. monocytogenes and L. welshimeri biofilms were more tolerant to quaternary ammonium compound-based sanitizers than were L. innocua biofilms. These findings extend our understanding of the application of commonly used sanitizers in the food industry and the efficacy of these sanitizers against Listeria species and their associated biofilms.}, } @article {pmid30109118, year = {2018}, author = {Gomez-Carretero, S and Libberton, B and Svennersten, K and Persson, K and Jager, E and Berggren, M and Rhen, M and Richter-Dahlfors, A}, title = {Erratum: Author Correction: Redox-active conducting polymers modulate Salmonella biofilm formation by controlling availability of electron acceptors.}, journal = {NPJ biofilms and microbiomes}, volume = {4}, number = {}, pages = {19}, doi = {10.1038/s41522-018-0061-6}, pmid = {30109118}, issn = {2055-5008}, abstract = {[This corrects the article DOI: 10.1038/s41522-017-0027-0.].}, } @article {pmid30109045, year = {2018}, author = {Hannig, C and Helbig, R and Hilsenbeck, J and Werner, C and Hannig, M}, title = {Impact of the springtail's cuticle nanotopography on bioadhesion and biofilm formation in vitro and in the oral cavity.}, journal = {Royal Society open science}, volume = {5}, number = {7}, pages = {171742}, pmid = {30109045}, issn = {2054-5703}, abstract = {Springtails (Collembola) have a nanostructured cuticle. To evaluate and to understand anti-biofouling properties of springtail cuticles' morphology under different conditions, springtails, shed cuticles and cuticle replicates were studied after incubation with protein solutions and bacterial cultures using common in vitro models. In a second step, they were exposed to human oral environment in situ in order to explore potential application in dentistry. In vitro, the cuticular structures were found to resist wetting by albumin solutions for up to 3 h and colonization by Staphylococcus epidermidis was inhibited. When exposed in the oral cavity, initial pellicle formation was of high heterogeneity: parts of the surface were coated by adsorbed proteins, others remained uncoated but exhibited locally attached, 'bridging', proteinaceous membranes spanning across cavities of the cuticle surface; this unique phenomenon was observed for the first time. Also the degree of bacterial colonization varied considerably. In conclusion, the springtail cuticle partially modulates bioadhesion in the oral cavity in a unique and specific manner, but it has no universal effect. Especially after longer exposure, the nanotextured surface of springtails is masked by the pellicle, resulting in subsequent bacterial colonization, and, thus, cannot effectively avoid bioadhesion in the oral cavity comprehensively. Nevertheless, the observed phenomena offer valuable information and new perspectives for the development of antifouling surfaces applicable in the oral cavity.}, } @article {pmid30108735, year = {2017}, author = {Manukumar, HM and Chandrasekhar, B and Rakesh, KP and Ananda, AP and Nandhini, M and Lalitha, P and Sumathi, S and Qin, HL and Umesha, S}, title = {Novel T-C@AgNPs mediated biocidal mechanism against biofilm associated methicillin-resistant Staphylococcus aureus (Bap-MRSA) 090, cytotoxicity and its molecular docking studies.}, journal = {MedChemComm}, volume = {8}, number = {12}, pages = {2181-2194}, pmid = {30108735}, issn = {2040-2503}, abstract = {Staphylococcus aureus is a commonly found pathogen that can cause food-spoilage and life threatening infections. However, the potential molecular effects of natural active thymol molecules and chitosan silver nanoparticles (C@AgNPs) in bacteria remain unclear. This gap in the literature has prompted us to study the effects of thymol loaded chitosan silver nanoparticles (T-C@AgNPs) against biofilm associated proteins in methicillin-resistant S. aureus (Bap-MRSA) 090 and also their toxicity, anti-cancer activity, and validation of their in silico molecular docking. The results showed excellent antibacterial activity of T-C@AgNPs against Bap-MRSA 090, having a minimum inhibitory concentration of 100 μg mL[-1] and a 10.08 ± 0.06 mm zone of inhibition (ZOI). The cyclic voltammogram (CV) analysis clearly showed pore forming of T-C@AgNPs at 300 μg mL[-1] concentration, and evidence of the interruption of the electron transport chain was clearly seen. The 200 μg mL[-1] concentration exhibited a 52.60 ± 0.25% anti-biofilm property by T-C@AgNPs against Bap-MRSA 090. The T-C@AgNPs showed no toxicity to peripheral blood mononuclear cells (PBMC) (IC50 = 221 ± 0.71 μg mL[-1]) compared to the control, and anti-cancer activity against human triple negative breast cancer cell line (MDA-MB-231) (IC50 110 ± 1.0 μg mL[-1]) compared to the standard drug Doxorubicin (IC50 = 19 ± 1.0). The excellent properties of T-C@AgNPs were validated by in silico molecular docking studies and showed best match scoring to target proteins compared to standards. These excellent properties of T-C@AgNPs highlight for the first time its pharmacology and potential in medicinal drug development applications for future research.}, } @article {pmid30107778, year = {2018}, author = {Pericolini, E and Colombari, B and Ferretti, G and Iseppi, R and Ardizzoni, A and Girardis, M and Sala, A and Peppoloni, S and Blasi, E}, title = {Real-time monitoring of Pseudomonas aeruginosa biofilm formation on endotracheal tubes in vitro.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {84}, pmid = {30107778}, issn = {1471-2180}, mesh = {Anti-Infective Agents ; Biofilms/*growth & development ; Catheters/*microbiology ; Equipment Contamination ; In Vitro Techniques/methods ; Intubation, Intratracheal/*instrumentation ; Pseudomonas aeruginosa/genetics/growth & development/*metabolism ; Time Factors ; Virulence/genetics ; }, abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for both acute and chronic infections in humans. In particular, its ability to form biofilm, on biotic and abiotic surfaces, makes it particularly resistant to host's immune defenses and current antibiotic therapies as well. Innovative antimicrobial materials, like hydrogel, silver salts or nanoparticles have been used to cover new generation catheters with promising results. Nevertheless, biofilm remains a major health problem. For instance, biofilm produced onto endotracheal tubes (ETT) of ventilated patients plays a relevant role in the onset of ventilation-associated pneumonia. Most of our knowledge on Pseudomonas aeruginosa biofilm derives from in vitro studies carried out on abiotic surfaces, such as polystyrene microplates or plastic materials used for ETT manufacturing. However, these approaches often provide underestimated results since other parameters, in addition to bacterial features (i.e. shape and material composition of ETT) might strongly influence biofilm formation.

RESULTS: We used an already established biofilm development assay on medically-relevant foreign devices (CVC catheters) by a stably transformed bioluminescent (BLI)-Pseudomonas aeruginosa strain, in order to follow up biofilm formation on ETT by bioluminescence detection. Our results demonstrated that it is possible: i) to monitor BLI-Pseudomonas aeruginosa biofilm development on ETT pieces in real-time, ii) to evaluate the three-dimensional structure of biofilm directly on ETT, iii) to assess metabolic behavior and the production of microbial virulence traits of bacteria embedded on ETT-biofilm.

CONCLUSIONS: Overall, we were able to standardize a rapid and easy-to-perform in vitro model for real-time monitoring Pseudomonas aeruginosa biofilm formation directly onto ETT pieces, taking into account not only microbial factors, but also ETT shape and material. Our study provides a rapid method for future screening and validation of novel antimicrobial drugs as well as for the evaluation of novel biomaterials employed in the production of new classes of ETT.}, } @article {pmid30107456, year = {2018}, author = {Coenye, T and Kjellerup, B}, title = {Editorial: Cross-disciplinary biofilm research-an introduction to the fourth thematic issue on biofilms.}, journal = {Pathogens and disease}, volume = {76}, number = {6}, pages = {}, doi = {10.1093/femspd/fty061}, pmid = {30107456}, issn = {2049-632X}, } @article {pmid30107112, year = {2018}, author = {Seo, Y and Leong, J and Park, JD and Hong, YT and Chu, SH and Park, C and Kim, DH and Deng, YH and Dushnov, V and Soh, J and Rogers, S and Yang, YY and Kong, H}, title = {Diatom Microbubbler for Active Biofilm Removal in Confined Spaces.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {42}, pages = {35685-35692}, pmid = {30107112}, issn = {1944-8252}, support = {R01 HL109192/HL/NHLBI NIH HHS/United States ; R21 HL131469/HL/NHLBI NIH HHS/United States ; }, mesh = {*Biofilms ; *Confined Spaces ; Diatoms/*chemistry ; Hydrogen Peroxide/chemistry ; Manganese Compounds/chemistry ; *Microbubbles ; Nanoparticles/chemistry/ultrastructure ; Oxides/chemistry ; Solutions ; }, abstract = {Bacterial biofilms form on and within many living tissues, medical devices, and engineered materials, threatening human health and sustainability. Removing biofilms remains a grand challenge despite tremendous efforts made so far, particularly when they are formed in confined spaces. One primary cause is the limited transport of antibacterial agents into extracellular polymeric substances (EPS) of the biofilm. In this study, we hypothesized that a microparticle engineered to be self-locomotive with microbubbles would clean a structure fouled by biofilm by fracturing the EPS and subsequently improving transports of the antiseptic reagent. We examined this hypothesis by doping a hollow cylinder-shaped diatom biosilica with manganese oxide (MnO2) nanosheets. In an antiseptic H2O2 solution, the diatoms doped by MnO2 nanosheets, denoted as diatom bubbler, discharged oxygen gas bubbles continuously and became self-motile. Subsequently, the diatoms infiltrated the bacterial biofilm formed on either flat or microgrooved silicon substrates and continued to generate microbubbles. The resulting microbubbles merged and converted surface energy to mechanical energy high enough to fracture the matrix of biofilm. Consequently, H2O2 molecules diffused into the biofilm and killed most bacterial cells. Overall, this study provides a unique and powerful tool that can significantly impact current efforts to clean a wide array of biofouled products and devices.}, } @article {pmid30106284, year = {2018}, author = {Lai, CY and Dong, QY and Chen, JX and Zhu, QS and Yang, X and Chen, WD and Zhao, HP and Zhu, L}, title = {Role of Extracellular Polymeric Substances in a Methane Based Membrane Biofilm Reactor Reducing Vanadate.}, journal = {Environmental science & technology}, volume = {52}, number = {18}, pages = {10680-10688}, doi = {10.1021/acs.est.8b02374}, pmid = {30106284}, issn = {1520-5851}, mesh = {Biofilms ; Bioreactors ; Extracellular Polymeric Substance Matrix ; *Methane ; *Vanadates ; }, abstract = {For the first time, we demonstrated vanadate (V(V)) reduction in a membrane biofilm reactor (MBfR) using CH4 as the sole electron donor. The V(V)-reducing capability of the biofilm kept increasing, with complete removal of V(V) achieved when the influent surface loading of V(V) was 363 mg m[-2] day[-1]. Almost all V(V) was reduced to V(IV) precipitates, which is confirmed by a scanning electron microscope coupled to energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Microbial community analysis revealed that denitrifiers Methylomonas and Denitratisoma might be the main genera responsible for V(V) reduction. The constant enrichment of Methylophilus suggests that the intermediate (i.e., methanol) from CH4 metabolism might be used as the electron carriers for V(V) bioreduction. Intrusion of V(V) (2-5 mg/L, at the surface loading of 150-378 mg m[-2] day[-1]) into the biofilm stimulated the secretion of extracellular polymeric substances (EPS), but high loading of V(V) (10 mg/L, at the surface loading of 668 mg m[-2] day[-1]) decreased the amount of EPS. Metagenomic prediction analysis established the strong correlation between the secretion of EPS and the microbial metabolism associated with V(V) reduction, tricarboxylic acid cycle (TCA) cycle, methane oxidation, and ATP production, and EPS might relieve the oxidative stress induced by high loading of V(V). Colorimetric determination and a three-dimensional excitation-emission matrix (3D-EEM) showed that tryptophan and humic acid-like substances might play important roles in microbial cell protection and V(V) binding. Fourier transform infrared (FTIR) spectroscopy identified hydroxyl (-OH) and carboxyl (COO[-]) groups in EPS as the candidate functional groups for binding V(V).}, } @article {pmid30105835, year = {2019}, author = {Hartmann, RC and Neuvald, L and Barth, V and de Figueiredo, JAP and de Oliveira, SD and Scarparo, RK and Waltrick, SB and Rossi-Fedele, G}, title = {Antimicrobial efficacy of 0.5% peracetic acid and EDTA with passive ultrasonic or manual agitation in an Enterococcus faecalis biofilm model.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {45}, number = {1}, pages = {57-63}, doi = {10.1111/aej.12279}, pmid = {30105835}, issn = {1747-4477}, mesh = {*Anti-Infective Agents ; Biofilms ; Dental Pulp Cavity ; Edetic Acid ; *Enterococcus faecalis ; Humans ; Peracetic Acid ; Root Canal Irrigants ; Root Canal Preparation ; Sodium Hypochlorite ; Therapeutic Irrigation ; Ultrasonics ; }, abstract = {We compared the antimicrobial efficacy of EDTA and 0.5% peracetic acid (PAA), with manual agitation (MA) or passive ultrasonic irrigation (PUI) in an Enterococcus faecalis biofilm model. Fifty-five single-rooted human premolar teeth were chemo-mechanically prepared and inoculated with E. faecalis for biofilm formation. These were divided into five groups (n = 11): saline solution, PAA+MA, PAA+PUI, EDTA+MA and EDTA+PUI. Root canal sampling and scanning electron microscopy of the canal lumen and dentinal tubule areas at the different root thirds were performed. The images were ranked based on contamination level. Only the PAA groups presented with no bacterial growth, with the remaining groups not presenting significant differences among them. PAA+PUI presented with the highest median position rankings in every third and location, whereas EDTA+MA performed similarly to the saline control. No differences were found when comparing MA and PUI within the same solution, however, PUI was associated with lower contamination levels mean rankings.}, } @article {pmid30105081, year = {2018}, author = {Viola, CM and Torres-Carro, R and Cartagena, E and Isla, MI and Alberto, MR and Arena, ME}, title = {Effect of Wine Wastes Extracts on the Viability and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus Strains.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2018}, number = {}, pages = {9526878}, pmid = {30105081}, issn = {1741-427X}, abstract = {In this work, we intended to inhibit the biofilm synthesis and the metabolism of Gram-positive and Gram-negative bacteria using two highly available wastes (stem and marc) obtained after the manufacturing of Torrontes wine at Cafayate, Argentina. Wine wastes contain a significant amount of bioactive compounds, mainly phenolic compounds, which makes them a potential source of compounds with beneficial properties to human health, as they could inhibit the virulence of pathogenic bacteria or protect the tissue against oxidative stress. Marc and stem extracts of Torrontes wine were evaluated for their ability to inhibit the metabolism and biofilm production of Pseudomonas aeruginosa and Staphylococcus aureus strains. The phytochemical composition and antioxidant activity of these extracts were also determined. The methanol and ethyl acetate extracts, which contained the highest amount of total polyphenolic, exhibited the highest scavenging capacity of ABTS and nitric oxide and the strongest Fe[3+] reducing power and exhibited the highest level of inhibition of the biofilm formation and of the metabolic activity in bacterial biofilm. We also noticed a positive correlation between phenolic compounds content, the antioxidant activity, and the anti-biofilm capacity of the winemaking wastes. These results display the potentiality of wine wastes to prevent or reduce the formation of biofilm. Moreover, their abundance makes them an attractive and affordable source of antibiofilm and antioxidant agents.}, } @article {pmid30104272, year = {2018}, author = {Guillon, A and Fouquenet, D and Morello, E and Henry, C and Georgeault, S and Si-Tahar, M and Hervé, V}, title = {Treatment of Pseudomonas aeruginosa Biofilm Present in Endotracheal Tubes by Poly-l-Lysine.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {11}, pages = {}, pmid = {30104272}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Equipment Contamination ; Humans ; Intubation, Intratracheal/*adverse effects ; Microscopy, Electron, Scanning/methods ; Pneumonia, Ventilator-Associated/drug therapy ; Polylysine/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Respiration, Artificial/*adverse effects ; Swine ; }, abstract = {The endotracheal tube (ETT) is an essential interface between the patient and ventilator in mechanically ventilated patients. However, a microbial biofilm is formed gradually on this tube and is associated with the development of ventilator-associated pneumonia. The bacteria present in the biofilm are more resistant to antibiotics, and current medical practices do not make it possible to eliminate. Pseudomonas aeruginosa is one of the leading pathogens that cause biofilm infections and ventilator-associated pneumonia. Poly-l-lysine (pLK) is a cationic polypeptide possessing antibacterial properties and mucolytic activity by compacting DNA. Here, we explored the antibiofilm activity of pLK to treat P. aeruginosa biofilms on ETTs while taking into consideration the necessary constraints for clinical translation in our experimental designs. First, we showed that pLK eradicates a P. aeruginosa biofilm formed in vitro on 96-well microplates. We further demonstrated that pLK alters bacterial membrane integrity, as revealed by scanning electron microscopy, and eventually eradicates biofilm formed either by reference or clinical strains of P. aeruginosa biofilms generated in vitro on ETTs. Second, we collected the ETT from patients with P. aeruginosa ventilator-associated pneumonia. We observed that a single dose of pLK is able to immediately disrupt the biofilm structure and kills more than 90% of bacteria present in the biofilm. Additionally, we did not observe any lung tolerance issue when the pLK solution was instilled into the ETT of ventilated pigs, an animal model particularly relevant to mimic invasive mechanical ventilation in humans. In conclusion, pLK appears as an innovative antibiofilm molecule, which could be applied in the ETT of mechanically ventilated patients.}, } @article {pmid30101982, year = {2018}, author = {Puah, SM and Tan, JAMA and Chew, CH and Chua, KH}, title = {Diverse Profiles of Biofilm and Adhesion Genes in Staphylococcus Aureus Food Strains Isolated from Sushi and Sashimi.}, journal = {Journal of food science}, volume = {83}, number = {9}, pages = {2337-2342}, doi = {10.1111/1750-3841.14300}, pmid = {30101982}, issn = {1750-3841}, support = {UM.TNC2/IPPP/PPGP/638/BK071-2015//University Malaya Research Fund Assistance (BKP) Grant/ ; }, mesh = {Animals ; Bacterial Proteins/*genetics ; *Biofilms ; Fishes/microbiology ; *Food Microbiology ; Foodborne Diseases/microbiology ; *Genes, Bacterial ; Humans ; Seafood/*microbiology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*genetics/isolation & purification/pathogenicity ; }, abstract = {UNLABELLED: Staphylococcus aureus is able to form multilayer biofilms embedded within a glycocalyx or slime layer. Biofilm formation poses food contamination risks and can subsequently increase the risk of food poisoning. Identification of food-related S. aureus strains will provide additional data on staphylococcal food poisoning involved in biofilm formation. A total of 52 S. aureus strains isolated from sushi and sashimi was investigated to study their ability for biofilm formation using crystal violet staining. The presence of accessory gene regulator (agr) groups and 15 adhesion genes was screened and their associations in biofilm formation were studied. All 52 S. aureus strains showed biofilm production on the tested hydrophobic surface with 44% (23/52) strains classified as strong, 33% (17/52) as moderate, and 23% (12/52) as weak biofilm producers. The frequency of agr-positive strains was 71% (agr group 1 = 21 strains; agr group 2 = 2 strains; agr group 3 = 12 strains; agr group 4 = 2 strains) whereas agr-negative strains were 29% (15/52). Twelve adhesion genes were detected and 98% of the S. aureus strains carried at least one adhesion gene. The ebps was significantly (p < .05) associated with strong biofilm producing strains. In addition, eno, clfA, icaAD, sasG, fnbB, cna, and sasC were significantly higher in the agr-positive group compared to the agr-negative group. The results of this study suggest that the presence of ebps, eno, clfA, icaAD, sasG, fnbB, cna, and sasC may play an important role in enhancing the stage of biofilm-related infections and warrants further investigation.

PRACTICAL APPLICATION: This work contributes to the knowledge on the biofilm formation and the distribution of agr groups in S. aureus strains as well as microbial surface components in recognizing adherence matrix molecules of organisms isolated from ready-to-eat sushi and sashimi. The findings provide valuable information to further study the roles of specific genes in causing biofilm-related infections.}, } @article {pmid30100555, year = {2018}, author = {Adler, E and Miller, D and Rock, O and Spierer, O and Forster, R}, title = {Microbiology and biofilm of corneal sutures.}, journal = {The British journal of ophthalmology}, volume = {102}, number = {11}, pages = {1602-1606}, doi = {10.1136/bjophthalmol-2018-312133}, pmid = {30100555}, issn = {1468-2079}, support = {P30 EY014801/EY/NEI NIH HHS/United States ; }, mesh = {Bacteria/*isolation & purification/ultrastructure ; Bacteriological Techniques ; Biofilms/*growth & development ; Cornea/microbiology ; Eye Infections, Bacterial/*microbiology ; Humans ; Keratitis/*microbiology ; *Keratoplasty, Penetrating ; Microscopy, Electron, Scanning ; Prospective Studies ; Sutures/*microbiology ; }, abstract = {AIM: To investigate the relationships between corneal suture bacteriology, biofilm and the clinical setting using culture studies and scanning electron microscopy (SEM).

METHODS: This is a prospective, observational study of patients with a history of penetrating keratoplasty presenting to a tertiary cornea clinic for routine or symptoms-related corneal suture removal. We documented for each patient the suture clinical setting (quiescent, exposed and keratitis-related), retention time, antimicrobial therapy, bacterial growth on culture studies, and bacterial presence and biofilm coverage on SEM.

RESULTS: There were significantly different culture positivity rates between the quiescent (8%), exposed (12%) and keratitis-related (60%) suture groups (p=0.039). As expected, keratitis-related sutures had the longest retention time compared with quiescent and exposed ones (p=0.02). The biofilm coverage score was higher for sutures from the keratitis-related and exposed groups, although this trend was not statistically significant (p=0.90). Higher biofilm scores were seen in samples that also yielded a positive culture result (p=0.36) and in samples with bacterial presence on SEM images (p=0.16 and p=0.73). Both of these were important trends but not statistically significant.

CONCLUSIONS: Evidence for active bacterial and biofilm presence on corneal sutures was found. Corneal sutures should be considered for removal sooner, before becoming exposed and/or keratitis-related. Traditional culture studies and SEM imaging are helpful in investigating biofilm and its clinical importance. More studies of the spectrum of bacterial growth on embedded biomedical devices such as corneal sutures are needed.}, } @article {pmid30098341, year = {2018}, author = {Erskine, E and MacPhee, CE and Stanley-Wall, NR}, title = {Functional Amyloid and Other Protein Fibers in the Biofilm Matrix.}, journal = {Journal of molecular biology}, volume = {430}, number = {20}, pages = {3642-3656}, pmid = {30098341}, issn = {1089-8638}, support = {BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N022254/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Amyloid/chemistry/*metabolism ; Amyloidogenic Proteins/chemistry/metabolism ; Bacterial Proteins/chemistry/*metabolism ; Biofilms ; Biophysical Phenomena ; Chemical Phenomena ; Disease Susceptibility ; Escherichia coli Proteins/chemistry/metabolism ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; Pseudomonas/physiology ; Solubility ; Spectrum Analysis ; Structure-Activity Relationship ; }, abstract = {Biofilms are ubiquitous in the natural and man-made environment. They are defined as microbes that are encapsulated in an extracellular, self-produced, biofilm matrix. Growing evidence from the genetic and biochemical analysis of single species biofilms has linked the presence of fibrous proteins to a functional biofilm matrix. Some of these fibers have been described as functional amyloid or amyloid-like fibers. Here we provide an overview of the biophysical and biological data for a wide range of protein fibers found in the biofilm matrix of Gram-positive and Gram-negative bacteria.}, } @article {pmid30097756, year = {2019}, author = {da Silveira, PV and Panariello, BHD and de Araújo Costa, CAG and Maule, SM and Maule, SM and Janal, MN and Zanin, ICJ and Duarte, S}, title = {Twice-daily red and blue light treatment for Candida albicans biofilm matrix development control.}, journal = {Lasers in medical science}, volume = {34}, number = {3}, pages = {441-447}, pmid = {30097756}, issn = {1435-604X}, support = {CAPES 88881.062159̷ 2014-01 PVE̷ CAPES//Coordination for the Improvement of Higher Level Personnel (CAPES)/ ; }, mesh = {Biofilms/drug effects/*radiation effects ; Candida albicans/drug effects/*physiology/*radiation effects ; Chlorhexidine/pharmacology ; Confidence Intervals ; Extracellular Polymeric Substance Matrix/*radiation effects ; Humans ; Photosensitizing Agents/pharmacology ; *Phototherapy ; }, abstract = {Phototherapy has been proposed as a direct means of affecting local bacterial infections. However, the use of phototherapy to prevent fungal biofilm development has received comparatively less attention. This study aimed to determine the effects of red light treatment and blue light treatment, without a photosensitizer, on the development of Candida albicans biofilm. During the development of 48-h biofilms of C. albicans SN 425 (n = 10), the biofilms were exposed twice-daily to noncoherent blue and red light (LumaCare; 420 nm and 635 nm). The energy density applied was 72 J cm[-2] for blue light and 43.8 J cm[2], 87.6 J cm[2], and 175.5 J cm[2] for red light. Positive control (PC) and negative control (NC) groups were treated twice-daily for 1 min with 0.12% chlorhexidine (CHX) and 0.89% NaCl respectively. Biofilms were analyzed for colony forming units (CFU), dry-weight, and exopolysaccharides (EPS-soluble and EPS-insoluble). Data was analyzed by one-way ANOVA and Tukey post hoc test (α = 0.05). Dry-weight was lower than NC (p < 0.001) and approached PC levels with both red and blue light treatments. CFU were also lower in groups exposed to blue light and higher durations of red light (p < 0.05). EPS-soluble and EPS-insoluble measures were variably reduced by these light exposures. In conclusion, twice-daily exposure to both blue and red lights affect the biofilm development and physiology of polysaccharide production and are potential mechanisms for the control of C. albicans biofilm matrix development.}, } @article {pmid30097647, year = {2018}, author = {van Wolferen, M and Orell, A and Albers, SV}, title = {Archaeal biofilm formation.}, journal = {Nature reviews. Microbiology}, volume = {16}, number = {11}, pages = {699-713}, doi = {10.1038/s41579-018-0058-4}, pmid = {30097647}, issn = {1740-1534}, mesh = {Archaea/genetics/*physiology ; Bacteria/*genetics ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; }, abstract = {Biofilms are structured and organized communities of microorganisms that represent one of the most successful forms of life on Earth. Bacterial biofilms have been studied in great detail, and many molecular details are known about the processes that govern bacterial biofilm formation, however, archaea are ubiquitous in almost all habitats on Earth and can also form biofilms. In recent years, insights have been gained into the development of archaeal biofilms, how archaea communicate to form biofilms and how the switch from a free-living lifestyle to a sessile lifestyle is regulated. In this Review, we explore the different stages of archaeal biofilm development and highlight similarities and differences between archaea and bacteria on a molecular level. We also consider the role of archaeal biofilms in industry and their use in different industrial processes.}, } @article {pmid30096872, year = {2018}, author = {Caputo, P and Di Martino, MC and Perfetto, B and Iovino, F and Donnarumma, G}, title = {Use of MALDI-TOF MS to Discriminate between Biofilm-Producer and Non-Producer Strains of Staphylococcus epidermidis.}, journal = {International journal of environmental research and public health}, volume = {15}, number = {8}, pages = {}, pmid = {30096872}, issn = {1660-4601}, mesh = {Biofilms/*growth & development ; Humans ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*classification/*growth & development ; }, abstract = {For the management of Staphylococci coagulase-negative infection, often related to biofilm formation, rapid and accurate identification is necessary in choosing a correct antibiotic therapy. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is becoming increasingly important for bacterial identification over traditional methods. Our aim was to validate the use of MALDI to discriminate Staphylococcus epidermidis biofilm-producing strains. Clinical strains coming from suture wires were identified and their protein profiles were compared to that obtained from two ATCC reference strains (biofilm producer and non-producer). MALDI identified the eighteen isolates as S. epidermidis, combining sixteen profiles with the biofilm producer and two with the non-producer, confirming the results of crystal violet assay. Our data highlight that MALDI can be considered a good tool to discriminate between biofilm-producer and non-producer strains of S. epidermidis, thus helping to establish an effective antibiotic therapy.}, } @article {pmid30096668, year = {2019}, author = {Morón-López, J and Nieto-Reyes, L and Senán-Salinas, J and Molina, S and El-Shehawy, R}, title = {Recycled desalination membranes as a support material for biofilm development: A new approach for microcystin removal during water treatment.}, journal = {The Science of the total environment}, volume = {647}, number = {}, pages = {785-793}, doi = {10.1016/j.scitotenv.2018.07.435}, pmid = {30096668}, issn = {1879-1026}, mesh = {Biofilms/*growth & development ; Membranes, Artificial ; Microcystins/*analysis ; Osmosis ; Waste Disposal, Fluid ; Water Pollutants/analysis ; Water Purification/*methods ; }, abstract = {Increased harmful cyanobacterial blooms and drought are some negative impacts of global warming. To deal with cyanotoxin release during water treatment, and to manage the massive quantities of end-of-life membrane waste generated by desalination processes, we propose an innovative biological system developed from recycled reverse osmosis (RO) membranes to remove microcystins (MC). Our system, named the Recycled-Membrane Biofilm Reactor (R-MBfR), effectively removes microcystins, while reducing the pollution impact of RO membrane waste by prolonging their life span at the same time. This multidisciplinary work showed that the inherent flaw of RO membranes, i.e., fouling, can be considered an advantageous characteristic for biofilm attachment. Factors such as roughness, hydrophilic surfaces, and the role of calcium in cell-cell and cell-surface interactions, encouraged bacterial growth on discarded membranes. Biofilm development was stimulated by using a laboratory-scale membrane module simulator cell. The R-MBfR proved versatile and was capable of degrading 2 mg·L[-1] of MC in 24 h. The economic feasibility of the scaling-up of the hypothetical R-MBfR was also validated. Therefore, this membrane recycling could be a future green cost-effective alternative technology for MC removal.}, } @article {pmid30096560, year = {2018}, author = {Ostadhossein, F and Misra, SK and Tripathi, I and Kravchuk, V and Vulugundam, G and LoBato, D and Selmic, LE and Pan, D}, title = {Dual purpose hafnium oxide nanoparticles offer imaging Streptococcus mutans dental biofilm and fight it In vivo via a drug free approach.}, journal = {Biomaterials}, volume = {181}, number = {}, pages = {252-267}, doi = {10.1016/j.biomaterials.2018.07.053}, pmid = {30096560}, issn = {1878-5905}, mesh = {Animals ; Biofilms/drug effects ; Female ; Hafnium/*chemistry ; Mass Spectrometry ; Nanoparticles/*chemistry ; Oxides/*chemistry ; Plasmids/genetics ; Rats ; Rats, Sprague-Dawley ; Streptococcal Infections/drug therapy ; Streptococcus mutans/*drug effects/*pathogenicity ; }, abstract = {The removal of tenacious dental plaque is of paramount importance; however, early diagnosis can be a challenging task in dental clinics due to the limitations of current approaches, specifically X-ray-based techniques. We have approached this problem by integrating antibacterial properties and X-ray contrast enhancement in a single probe specific to colonies of Streptococcus mutans as the most predominant and carious oral bacteria. We report the synthesis of an inherently therapeutic polymeric silane conjugated hafnium oxide nanoparticles (Hf PS NPs). Using a high-affinity pathogen-selective peptide, the concept of molecularly targeted X-ray imaging of cariogenic pathogen S. mutans was demonstrated. Ex vivo studies using extracted human tooth demonstrated striking X-ray attenuation of NPs vs. tooth. Additionally, Hf PS NPs exhibited significant bactericidal properties against cariogenic pathogen. Electron microscopy revealed that the antibacterial activity occurred via a 'latch and kill' mechanism. Mechanistic studies determined that these NPs fragmented bacterial DNA components to exert their antimicrobial effect. Importantly, Hf PS NPs effectively inhibited the growth of a mature biofilm on an ex vivo human tooth model. Finally, the NPs were applied to the rodent model of dental biofilm. Topical administration of the Hf PS NPs for 8 days (1X daily) could effectively attenuate the S. mutans biofilm challenge. This report is the first of its kind to demonstrate that HfO2-based NPs can be used for simultaneous diagnosis and antibacterial treatment without requiring an additional drug.}, } @article {pmid30093898, year = {2018}, author = {Selvarajoo, K}, title = {Order Parameter in Bacterial Biofilm Adaptive Response.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1721}, pmid = {30093898}, issn = {1664-302X}, } @article {pmid30093624, year = {2018}, author = {Fernández-Barat, L and Ben-Aicha, S and Motos, A and Vila, J and Marco, F and Rigol, M and Muñoz, L and Li Bassi, G and Ferrer, M and Torres, A}, title = {Assessment of in vivo versus in vitro biofilm formation of clinical methicillin-resistant Staphylococcus aureus isolates from endotracheal tubes.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {11906}, pmid = {30093624}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Genotype ; Intubation, Intratracheal/adverse effects/*methods ; Linezolid/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/physiology ; Pneumonia, Ventilator-Associated/*drug therapy/microbiology ; Prospective Studies ; Random Allocation ; Swine ; Swine Diseases/drug therapy/microbiology ; Time Factors ; Vancomycin/pharmacology ; }, abstract = {Our aim was to demonstrate that biofilm formation in a clinical strain of methicillin-resistant Staphylococcus aureus (MRSA) can be enhanced by environment exposure in an endotracheal tube (ETT) and to determine how it is affected by systemic treatment and atmospheric conditions. Second, we aimed to assess biofilm production dynamics after extubation. We prospectively analyzed 70 ETT samples obtained from pigs randomized to be untreated (controls, n = 20), or treated with vancomycin (n = 32) or linezolid (n = 18). A clinical MRSA strain (MRSA-in) was inoculated in pigs to create a pneumonia model, before treating with antibiotics. Tracheally intubated pigs with MRSA severe pneumonia, were mechanically ventilated for 69 ± 16 hours. All MRSA isolates retrieved from ETTs (ETT-MRSA) were tested for their in vitro biofilm production by microtiter plate assay. In vitro biofilm production of MRSA isolates was sequentially studied over the next 8 days post-extubation to assess biofilm capability dynamics over time. All experiments were performed under ambient air (O2) or ambient air supplemented with 5% CO2. We collected 52 ETT-MRSA isolates (placebo N = 19, linezolid N = 11, and vancomycin N = 22) that were clonally identical to the MRSA-in. Among the ETT-MRSA isolates, biofilm production more than doubled after extubation in 40% and 50% under 5% CO2 and O2, respectively. Systemic antibiotic treatment during intubation did not affect this outcome. Under both atmospheric conditions, biofilm production for MRSA-in was at least doubled for 9 ETT-MRSA isolates, and assessment of these showed that biofilm production decreased progressively over a 4-day period after extubation. In conclusion, a weak biofilm producer MRSA strain significantly enhances its biofilm production within an ETT, but it is influenced by the ETT environment rather than by the systemic treatment used during intubation or by the atmospheric conditions used for bacterial growth.}, } @article {pmid30092027, year = {2018}, author = {Bosse, M and Heuwieser, A and Heinzel, A and Lukas, A and Oliveira, G and Mayer, B}, title = {Biomarker panels for characterizing microbial community biofilm formation as composite molecular process.}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0202032}, pmid = {30092027}, issn = {1932-6203}, mesh = {Bacteria/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Biomarkers/*metabolism ; Chemotaxis ; Copper/chemistry ; DNA, Bacterial/analysis ; Genetics, Population ; Homeostasis ; *Microbial Consortia ; Molecular Chaperones/*metabolism ; *Quorum Sensing ; Species Specificity ; }, abstract = {Microbial consortia execute collaborative molecular processes with contributions from individual species, on such basis enabling optimized molecular function. Such collaboration and synergies benefit metabolic flux specifically in extreme environmental conditions as seen in acid mine drainage, with biofilms as relevant microenvironment. However, knowledge about community species composition is not sufficient for deducing presence and efficiency of composite molecular function. For this task molecular resolution of the consortium interactome is to be retrieved, with molecular biomarkers particularly suited for characterizing composite molecular processes involved in biofilm formation and maintenance. A microbial species set identified in 18 copper environmental sites provides a data matrix for deriving a cross-species molecular process model of biofilm formation composed of 191 protein coding genes contributed from 25 microbial species. Computing degree and stress centrality of biofilm molecular process nodes allows selection of network hubs and central connectors, with the top ranking molecular features proposed as biomarker candidates for characterizing biofilm homeostasis. Functional classes represented in the biomarker panel include quorum sensing, chemotaxis, motility and extracellular polysaccharide biosynthesis, complemented by chaperones. Abundance of biomarker candidates identified in experimental data sets monitoring different biofilm conditions provides evidence for the selected biomarkers as sensitive and specific molecular process proxies for capturing biofilm microenvironments. Topological criteria of process networks covering an aggregate function of interest support the selection of biomarker candidates independent of specific community species composition. Such panels promise efficient screening of environmental samples for presence of microbial community composite molecular function.}, } @article {pmid30090964, year = {2019}, author = {Jamal, M and Andleeb, S and Jalil, F and Imran, M and Nawaz, MA and Hussain, T and Ali, M and Ur Rahman, S and Das, CR}, title = {Isolation, characterization and efficacy of phage MJ2 against biofilm forming multi-drug resistant Enterobacter cloacae.}, journal = {Folia microbiologica}, volume = {64}, number = {1}, pages = {101-111}, pmid = {30090964}, issn = {1874-9356}, support = {HEC-IRSIP- 2013//Higher Education Commision, Pakistan/ ; }, mesh = {Biofilms/*growth & development ; Calcium Chloride/pharmacology ; DNA, Viral ; *Drug Resistance, Multiple, Bacterial ; Enterobacter cloacae/*virology ; Genome Size ; Genome, Viral/genetics ; Host Specificity ; Hydrogen-Ion Concentration ; Magnesium Chloride/pharmacology ; Microbial Viability ; Molecular Weight ; Podoviridae/*isolation & purification/*physiology/ultrastructure ; Temperature ; Viral Proteins/chemistry ; Virus Attachment/drug effects ; Wastewater/virology ; }, abstract = {Biofilm is involved in a variety of infections, playing a critical role in the chronicity of infections. Enterobacter cloacae is a biofilm-forming and multi-drug-resistant (MDR) nosocomial pathogen leading to significant morbidity and mortality. This study aimed at isolation of a bacteriophage against MDR clinical strain of E. cloacae and its efficacy against bacterial planktonic cells and biofilm. A bacteriophage MJ2 was successfully isolated from wastewater and was characterized. The phage exhibited a wide range of thermal and pH stability and demonstrated considerable adsorption to host bacteria in the presence of CaCl2 or MgCl2. Transmission electron microscopy (TEM) showed MJ2 head as approximately 62 and 54 nm width and length, respectively. It had a short non-contractile tail and was characterized as a member of the family Podoviridae [order Caudovirales]. The phage MJ2 was found to possess 11 structural proteins (12-150 kDa) and a double-stranded DNA genome with an approximate size of 40 kb. The log-phase growth of E. cloacae both in biofilm and suspension was significantly reduced by the phage. The E. cloacae biofilm was formed under different conditions to evaluate the efficacy of MJ2 phage. Variable reduction pattern of E. cloacae biofilm was observed while treating it for 4 h with MJ2, i.e., biofilm under static conditions. The renewed media with intervals of 24, 72, and 120 h showed biomass decline of 2.8-, 3-, and 3.5-log, respectively. Whereas, the bacterial biofilm formed with dynamic conditions with refreshing media after 24, 72, and 120 h demonstrated decline in growth at 2.5-, 2.6-, and 3.3-log, respectively. It was, therefore, concluded that phage MJ2 possessed considerable inhibitory effects on MDR E. cloacae both in planktonic and biofilm forms.}, } @article {pmid30090117, year = {2018}, author = {Pourhajibagher, M and Chiniforush, N and Monzavi, A and Barikani, H and Monzavi, MM and Sobhani, S and Shahabi, S and Bahador, A}, title = {Inhibitory Effects of Antimicrobial Photodynamic Therapy with Curcumin on Biofilm-Associated Gene Expression Profile of Aggregatibacter actinomycetemcomitans.}, journal = {Journal of dentistry (Tehran, Iran)}, volume = {15}, number = {3}, pages = {169-177}, pmid = {30090117}, issn = {1735-2150}, abstract = {OBJECTIVES: Periodontitis is an inflammation of periodontal tissues that is caused by the biofilm of periodontal pathogens. Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is an opportunistic periodontopathogen that can be the cause of periodontal diseases via fimbriae as a virulence factor. In this study, we aimed to determine the expression level of A. actinomycetemcomitans rcpA gene as a virulence factor associated with biofilm formation after antimicrobial photodynamic therapy (aPDT) as a relatively new therapeutic modality.

MATERIALS AND METHODS: To determine sub-lethal doses of aPDT against A. actinomycetemcomitans ATCC 33384 strain, we used curcumin (CUR) as a photosensitizer at a final concentration of 40 μmol/ml, which was excited with a light-emitting diode (LED) at the wavelength of 450 nm. Quantitative real-time polymerase chain reaction (qRT-PCR) was then applied to monitor rcpA gene expression in A. actinomycetemcomitans.

RESULTS: 10-40 μmol/ml of CUR caused a significant reduction in the growth of A. actinomycetemcomitans compared to control group (P<0.05). Also, the cell viability of A. actinomycetemcomitans was significantly decreased after more than four minutes of LED irradiation. Therefore, the sub-lethal dose of aPDT against A. actinomycetemcomitans was 5 μmol/ml of CUR with three minutes of LED irradiation at a fluency of 180-240 J/cm[2], which reduced the expression of the rcpA gene by approximately 8.5-fold.

CONCLUSIONS: aPDT with CUR leads to decreased cell survival and virulence of A. actinomycetemcomitans. Thus, CUR-aPDT can be used as an alternative approach for the successful treatment of periodontitis in vivo.}, } @article {pmid30090115, year = {2018}, author = {Ghabraei, S and Bolhari, B and Sabbagh, MM and Afshar, MS}, title = {Comparison of Antimicrobial Effects of Triple Antibiotic Paste and Calcium Hydroxide Mixed with 2% Chlorhexidine as Intracanal Medicaments Against Enterococcus faecalis Biofilm.}, journal = {Journal of dentistry (Tehran, Iran)}, volume = {15}, number = {3}, pages = {151-160}, pmid = {30090115}, issn = {1735-2150}, abstract = {OBJECTIVES: The purpose of this in-vitro study was to determine and compare the shortest period needed for a triple antibiotic paste (TAP) and calcium hydroxide (Ca(OH)2) plus 2% chlorhexidine (CHX) to eradicate the biofilm of Enterococcus faecalis (EF) from the root canal system.

MATERIALS AND METHODS: Sixty-five extracted single-rooted human teeth with straight root canals were selected. The crowns were cut from the cementoenamel junction (CEJ), and canal preparations were done by step-back technique. The smear layer was removed by 17% ethylenediaminetetraacetic acid (EDTA) and 5.25% sodium hypochlorite (NaOCl). Afterwards, the samples were sterilized with gamma ray and were placed inside microtubes for one week. During this week, the teeth were infected with EF. Then, a TAP and Ca(OH)2 mixed with 2% CHX were inserted into the canals. The roots were cut longitudinally, and dentin chips were collected from the apical part of the roots by a round bur to the depth of 400 μm. The vital bacterial load was assessed by counting the numbers of colony-forming units (CFUs).

RESULTS: The paste of Ca(OH)2 mixed with 2% CHX was able to eradicate the EF biofilm in three days. The TAP was able to eradicate the biofilm of EF in seven days.

CONCLUSIONS: It seems that Ca(OH)2 mixed with 2% CHX is more potent than the TAP against EF biofilm.}, } @article {pmid30088827, year = {2019}, author = {Souza, JGS and Cordeiro, JM and Lima, CV and Barão, VAR}, title = {Citric acid reduces oral biofilm and influences the electrochemical behavior of titanium: An in situ and in vitro study.}, journal = {Journal of periodontology}, volume = {90}, number = {2}, pages = {149-158}, doi = {10.1002/JPER.18-0178}, pmid = {30088827}, issn = {1943-3670}, mesh = {Bacterial Adhesion ; Biofilms ; Citric Acid ; *Dental Implants ; Humans ; Surface Properties ; *Titanium ; }, abstract = {BACKGROUND: Citric acid (CA) has been suggested as an effective antimicrobial agent against biofilms formed on titanium. However, the antimicrobial effect of CA in biofilms formed in the oral environment and its effects on the physical properties of titanium surface remain unknown. Therefore, this study evaluated the antimicrobial effect of CA on in situ biofilm, whether this treatment favors the bacteria recolonization and its effect on the electrochemical properties of titanium.

METHODS: In the in situ test, volunteers wore a palatal appliance containing titanium discs. After 7 days, the discs (N = 21) were exposed in vitro to the following treatments: immersion in 0.9% sodium chloride (control); 40% CA immersion; and 40% CA rubbing. Afterwards, these discs (N = 18) were exposed in vitro to new bacterial adhesion with Streptococcus sanguinis. New discs (N = 18) without biofilm were exposed to the treatments and subjected to electrochemical tests and surface characterization. Data were analyzed by one-way ANOVA followed by Tukey's HSD test.

RESULTS: The CA groups showed a significant reduction (≈ 5-log reduction) in the biofilm formed in situ compared with the control group (p < 0.05), but no difference was found between CA application methods (p = 0.680). The acid treatment did not favor the recolonization of bacteria (p = 0.629). CA treatment did not influence the polarization resistance and capacitance of the oxide film, but statistically enhanced the electrochemical stability of titanium.

CONCLUSION: Citric acid appears to be an effective clinical alternative for treatment of the main etiologic factor in dental implant failure, biofilm formation, enhancing electrochemical behavior of titanium.}, } @article {pmid30086343, year = {2018}, author = {Mizdal, CR and Stefanello, ST and da Costa Flores, V and Agertt, VA and Bonez, PC and Rossi, GG and da Silva, TC and Antunes Soares, FA and de Lourenço Marques, L and de Campos, MMA}, title = {The antibacterial and anti-biofilm activity of gold-complexed sulfonamides against methicillin-resistant Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {440-448}, doi = {10.1016/j.micpath.2018.08.002}, pmid = {30086343}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Brazil ; Caenorhabditis elegans/drug effects ; Drug Synergism ; Gold/chemistry/*pharmacology ; Humans ; Methicillin Resistance/drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects ; Sulfonamides/chemistry/*pharmacology ; Toxicity Tests ; }, abstract = {The drug-resistant strains of Staphylococcus aureus have been considered as one of the serious health threats, which are related to high patient hospitalization rates. Besides, Staphylococcus aureus biofilm formation exhibits a drug-tolerant nature and shows nonspecific resistance against a broad-spectrum of antibiotics. The emergence of drug-resistant bacteria stimulated the development of novel medicines as a strategy to control infections. In this study, we evaluated the antibacterial and anti-biofilm activity of gold-complexed sulfonamides against Staphylococcus aureus strains such as methicillin-resistant S. aureus and clinical isolates. Our data showed that the exposure of gold-complexed sulfonamides promoted a remarkable reduction in the bacterial adhesion. Also, confocal microscopy displayed the effects of the compounds on in the bacterial cell biofilm, revealed that the compounds decreased the biofilm formation. Our results also demonstrated that gold-complexed sulfonamides exhibited potent antibacterial activity against Staphylococcus aureus strains. Besides, all compounds presented a synergic antibacterial activity when were associated with classical antibiotics. Gold-complexed sulfonamide compounds did not promote toxic effects on Caenorhabditis elegans. Thus, our results showed that the coordination of sulfonamide with gold is a promising alternative in the development of safe and active compounds against methicillin-resistant and clinical isolates S. aureus.}, } @article {pmid30084644, year = {2019}, author = {Wang, Z and Gong, X and Xie, J and Xu, Z and Liu, G and Zhang, G}, title = {Investigation of Formation of Bacterial Biofilm upon Dead Siblings.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {35}, number = {23}, pages = {7405-7413}, doi = {10.1021/acs.langmuir.8b01962}, pmid = {30084644}, issn = {1520-5827}, mesh = {*Biofilms ; Microscopy, Fluorescence ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Biocides can effectively kill bacteria; however, whether the dead bacterial cells left on the surface influence the later growth of biofilm is unknown. In this study, we have cultured Pseudomonas aeruginosa (PAO1) biofilm on their dead siblings and have investigated their evolution by using magnetic force modulation atomic force microscopy (MF-AFM). The time dependence of the biofilm thickness indicates that the deposited dead siblings can slow down the growth of PAO1 biofilm. The biofilm growing on dead bacteria layers is softer in comparison with those upon alive siblings, as reflected by the static elastic modulus (E) and dynamic stiffness (kd) scaled to the disturbing frequency (f) as kd = kd,0 f[γ], where kd,0 is the scaling factor and γ is the power-law exponent. We reveal that the smaller population instead of the variation of extracellular polymeric substances (EPS) within the biofilm upon the dead siblings is responsible for the softer biofilm. The present study provides a better understanding of the biofilm formation, thus, making it significant for designing antimicrobial medical materials and antifouling coatings.}, } @article {pmid30084122, year = {2018}, author = {Kern, ZT and Jacob, ME and Gilbertie, JM and Vaden, SL and Lyle, SK}, title = {Characteristics of Dogs with Biofilm-Forming Escherichia Coli Urinary Tract Infections.}, journal = {Journal of veterinary internal medicine}, volume = {32}, number = {5}, pages = {1645-1651}, pmid = {30084122}, issn = {1939-1676}, mesh = {Animals ; Biofilms/*growth & development ; Cross-Sectional Studies ; Dog Diseases/*microbiology ; Dogs ; Drug Resistance, Multiple, Bacterial ; Escherichia coli/*physiology ; Escherichia coli Infections/microbiology/*veterinary ; Female ; Male ; Retrospective Studies ; Urinary Tract Infections/microbiology/*veterinary ; }, abstract = {BACKGROUND: Bacterial urinary tract infections (UTIs) are common in companion animals. Increasing awareness of biofilm-forming bacteria raises concern regarding the appropriate diagnosis, treatment, and prognosis of UTIs associated with these organisms.

HYPOTHESIS/OBJECTIVES: To (1) describe the population of dogs with UTIs associated with biofilm-forming Escherichia coli and (2) determine whether or not clinical differences exist between dogs with biofilm-forming E. coli UTIs and dogs with nonbiofilm-forming E. coli UTIs. We hypothesized that there would be no difference in the population characteristics, but that biofilm-formation would be more prevalent in dogs with chronic, complicated, and asymptomatic UTIs.

ANIMALS: Seventy-six client-owned dogs with E. coli UTIs, divided into 2 groups based on the biofilm-forming capability of stored bacterial isolates as assessed by the crystal violet assay.

METHODS: Retrospective cross-sectional study. Medical records of the affected dogs were reviewed and their population and infection characteristics were compared.

RESULTS: Most (52.6%) E. coli isolates were capable of forming biofilms. Biofilm-forming E. coli had a lower likelihood (P < .001) of multidrug resistance than did nonbiofilm-forming E. coli. No statistically significant differences were identified between the population or infection characteristics of the 2 groups of dogs.

Escherichia coli isolated from canine urinary tracts are frequently capable of forming biofilms. Because no reliable clinical features allowed exclusion of biofilm formation, the potential for biofilm formation should be considered whenever E. coli UTI is diagnosed. The association of antibiotic resistance and biofilm potential may affect treatment of UTIs, but additional investigation is warranted.}, } @article {pmid30083138, year = {2018}, author = {Zhou, Y and Millhouse, E and Shaw, T and Lappin, DF and Rajendran, R and Bagg, J and Lin, H and Ramage, G}, title = {Evaluating Streptococcus mutans Strain Dependent Characteristics in a Polymicrobial Biofilm Community.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1498}, pmid = {30083138}, issn = {1664-302X}, abstract = {Aim: The purpose of this study was to investigate strain dependent differences of the cariogenic biofilm forming Streptococcus mutans within both simple and complex communities. Methods: A mono-species containing representative S. mutans clinical isolates (caries and non-caries), and a multispecies in vitro caries biofilm model containing Lactobacillus casei, Veillonella dispar, Fusobacterium nucleatum and Actinomyces naeslundii, and either of two representative S. mutans clinical isolates (caries and non-caries), was developed as a comparison model. Compositional analysis of total and live bacteria within biofilms, and transcriptional analysis of biofilm associated virulence factors were evaluated by live/dead PCR and quantitative PCR, respectively. Scanning electron microscopy (SEM) was used to analyze the architecture of biofilm. One-way analysis of variance and t-tests were used to investigate significant differences between independent groups of data. Results: Within a mono-species biofilm, different S. mutans strains responded similarly to one another during biofilm formation in different carbohydrate sources, with sucrose showing the highest levels of biofilm biomass and galactose showing the lowest. Within the polymicrobial biofilm system, compositional analysis of the bacteria within the biofilm showed that S. mutans derived from a caries-free patient was preferentially composed of both total and viable L. casei, whereas S. mutans derived from a caries patient was dominated by both total and viable S. mutans (p < 0.001). Normalized gene expression analysis of srtA, gtfB, ftf, spaP, gbpB, and luxS, showed a general upregulation within the S. mutans dominant biofilm. Conclusion: We were able to demonstrate that individual strains derived from different patients exhibited altered biofilm characteristics, which were not obvious within a simple mono-species biofilm model. Influencing the environmental conditions changed the composition and functionality S. mutans within the polymicrobial biofilm. The biofilm model described herein provides a novel and reproducible method of assessing the impact on the biofilm microbiome upon different environmental influences.}, } @article {pmid30082282, year = {2018}, author = {Poudyal, B and Sauer, K}, title = {The PA3177 Gene Encodes an Active Diguanylate Cyclase That Contributes to Biofilm Antimicrobial Tolerance but Not Biofilm Formation by Pseudomonas aeruginosa.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {10}, pages = {}, pmid = {30082282}, issn = {1098-6596}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects ; Escherichia coli Proteins/*genetics/*metabolism ; Gene Expression Regulation, Bacterial/drug effects/genetics ; Hydrogen Peroxide/pharmacology ; Microbial Sensitivity Tests ; Phosphorus-Oxygen Lyases/*genetics/*metabolism ; Pseudomonas aeruginosa/*drug effects/*genetics ; Tobramycin/pharmacology ; }, abstract = {A hallmark of biofilms is their heightened resistance to antimicrobial agents. Recent findings suggested a role for bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) in the susceptibility of bacteria to antimicrobial agents; however, no c-di-GMP modulating enzyme(s) contributing to the drug tolerance phenotype of biofilms has been identified. The goal of this study was to determine whether c-di-GMP modulating enzyme(s) specifically contributes to the biofilm drug tolerance of Pseudomonas aeruginosa Using transcriptome sequencing combined with biofilm susceptibility assays, we identified PA3177 encoding a probable diguanylate cyclase. PA3177 was confirmed to be an active diguanylate cyclase, with overexpression affecting swimming and swarming motility, and inactivation affecting cellular c-di-GMP levels of biofilm but not planktonic cells. Inactivation of PA3177 rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin and hydrogen peroxide. Inactivation of PA3177 also eliminated the recalcitrance of biofilms to killing by tobramycin, with multicopy expression of PA3177 but not PA3177_GGAAF harboring substitutions in the active site, restoring tolerance to wild-type levels. Susceptibility was linked to BrlR, a previously described transcriptional regulator contributing to biofilm tolerance, with inactivation of PA3177 negatively impacting BrlR levels and BrlR-DNA binding. While PA3177 contributed to biofilm drug tolerance, inactivation of PA3177 had no effect on attachment and biofilm formation. Our findings demonstrate for the first time that biofilm drug tolerance by P. aeruginosa is linked to a specific c-di-GMP modulating enzyme, PA3177, with the pool of PA3177-generated c-di-GMP only contributing to biofilm drug tolerance but not to biofilm formation.}, } @article {pmid30081568, year = {2018}, author = {Carbone, A and Parrino, B and Cusimano, MG and Spanò, V and Montalbano, A and Barraja, P and Schillaci, D and Cirrincione, G and Diana, P and Cascioferro, S}, title = {New Thiazole Nortopsentin Analogues Inhibit Bacterial Biofilm Formation.}, journal = {Marine drugs}, volume = {16}, number = {8}, pages = {}, pmid = {30081568}, issn = {1660-3397}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Aquatic Organisms/chemistry ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Humans ; Imidazoles/chemistry ; Indoles/chemistry ; Inhibitory Concentration 50 ; Staphylococcal Infections/drug therapy/microbiology/pathology ; Staphylococcus aureus/drug effects/physiology ; Thiazoles/chemical synthesis/*pharmacology ; }, abstract = {New thiazole nortopsentin analogues were conveniently synthesized and evaluated for their activity as inhibitors of biofilm formation of relevant Gram-positive and Gram-negative pathogens. All compounds were able to interfere with the first step of biofilm formation in a dose-dependent manner, showing a selectivity against the staphylococcal strains. The most active derivatives elicited IC50 values against Staphylococcus aureus ATCC 25923, ranging from 0.40[-]2.03 µM. The new compounds showed a typical anti-virulence profile, being able to inhibit the biofilm formation without affecting the microbial growth in the planktonic form.}, } @article {pmid30080666, year = {2018}, author = {Petruzzi, B and Dalloul, RA and LeRoith, T and Evans, NP and Pierson, FW and Inzana, TJ}, title = {Biofilm formation and avian immune response following experimental acute and chronic avian cholera due to Pasteurella multocida.}, journal = {Veterinary microbiology}, volume = {222}, number = {}, pages = {114-123}, doi = {10.1016/j.vetmic.2018.07.005}, pmid = {30080666}, issn = {1873-2542}, mesh = {Acute Disease ; Animals ; Biofilms/*growth & development ; Chemokines/immunology ; Chickens/*immunology ; Cholera/immunology/microbiology/mortality/*veterinary ; Chronic Disease ; Cytokines/immunology ; Pasteurella Infections/immunology/microbiology/mortality/*veterinary ; Pasteurella multocida/*immunology/isolation & purification/*pathogenicity ; Poultry Diseases/immunology/microbiology/mortality ; Th1 Cells/immunology ; Th17 Cells/immunology ; Virulence ; }, abstract = {Pasteurella multocida is the causative agent of avian cholera, an important economic and ecological disease that can present as a peracute, acute, chronic, or asymptomatic infection. Acute avian cholera is associated with encapsulated P. multocida, while chronic and asymptomatic cases of avian cholera may be associated with capsule-deficient P. multocida isolates. We hypothesize that biofilm formation is also associated with chronic and asymptomatic avian cholera. Experimental infections of chickens with encapsulated, biofilm-deficient P. multocida strain X73, proficient biofilm forming P. multocida strain X73ΔhyaD, and proficient biofilm forming clinical strains 775 and 756 showed that virulence was inversely correlated with biofilm formation. Biofilm-proficient isolates induced chronic avian cholera in the chicken host. Histopathological analysis was used to show that biofilm-proficient isolates induced little inflammation in the lungs, heart, and liver, while biofilm-deficient isolates induced greater inflammation and induced the recruitment of heterophil granulocytes. Putative biofilm matrix material and exopolysaccharide was detected in pulmonary tissue of chickens diagnosed with chronic avian cholera using scanning electron microscopy and a fluorescently-tagged lectin, respectively, supporting a role for biofilm in chronic avian cholera. P. multocida induced Th1 and Th17 immune responses during acute and chronic avian cholera, as determined by quantitative real-time PCR of splenic cytokine genes. Chickens that succumbed to acute avian cholera after experimental challenge with strain X73 had high levels of INF-γ, IL-1β, IL-6, IL-12A, IL-22, IL-17A, and IL-17RA expressed in the spleen compared to all other experimental groups. Birds infected with capsule-deficient strains had chronic infections lasting 7 days or longer, and had increased levels of IL-17RA, CCR6, and IL-16 compared to non-infected control chickens. However, specific antibody titers increased only transiently to capsule-deficient strains and were low, indicating that antibodies are less important in managing and clearing P. multocida infections.}, } @article {pmid30080406, year = {2018}, author = {Bogler, A and Bar-Zeev, E}, title = {Membrane Distillation Biofouling: Impact of Feedwater Temperature on Biofilm Characteristics and Membrane Performance.}, journal = {Environmental science & technology}, volume = {52}, number = {17}, pages = {10019-10029}, doi = {10.1021/acs.est.8b02744}, pmid = {30080406}, issn = {1520-5851}, mesh = {Biofilms ; *Biofouling ; Distillation ; Membranes, Artificial ; Osmosis ; Temperature ; *Water Purification ; }, abstract = {Membrane distillation (MD) is a temperature driven membrane separation technology that holds great potential for decentralized and sustainable wastewater treatment systems. Yet, similarly to all membrane based systems, microbial fouling (biofouling) might be a critical hurdle for MD wastewater treatment applications. In this study we determined the impact of increasing feedwater temperatures (47 °C, 55 °C, and 65 °C) on biofilm growth and MD performance via dynamic biofouling experiments with Anoxybacillus sp. as a model bacterium. Our results indicated that cell growth was reduced at 47 °C, resulting in moderate distillate water flux decline (30%). Differently, extensive growth of Anoxybacillus sp. at feedwater temperature of 55 °C caused severe distillate water flux decline (78%). Additionally, biofouling induced membrane wetting, which facilitated the passage of bacteria cells and endospores through the membrane structure into the distillate. Although bacterial growth was impaired at feedwater temperatures of 65 °C, excessive production of EPS (compared to bacterial abundance) crippled membrane separation due to severe pore wetting. These results underline the importance of optimized operating conditions and development of antibiofouling and antiwetting membranes for successful implementation of MD in wastewater treatment with high biofouling propensity.}, } @article {pmid30078968, year = {2018}, author = {Elkhashab, THT and Adel, LA and Nour, MS and Mahran, M and Elkaffas, M}, title = {Association of intercellular adhesion gene A with biofilm formation in staphylococci isolates from patients with conjunctivitis.}, journal = {Journal of laboratory physicians}, volume = {10}, number = {3}, pages = {309-315}, pmid = {30078968}, issn = {0974-2727}, abstract = {BACKGROUND: There is a great negative impact of biofilm-mediated infection on patient health which necessitates the use of reliable methods for detecting biofilm producers.

AIMS: This study was done to determine biofilm-producing ability and the presence of intercellular adhesion gene A in clinical staphylococcal isolates and to assess the reliability of two phenotypic methods used for biofilm detection.

MATERIALS AND METHODS: Fifty staphylococcal strains were isolated from 100 conjunctival swabs from patients attended the Ophthalmology Outpatient Department of the Research Institute of Ophthalmology. Two phenotypic methods were used for detection of biofilm production; qualitative congo red agar (CRA); and quantitative microtiter plate. Polymerase chain reaction was used to determine the presence of icaA gene.

RESULTS: In Staph aureus, 60% were positive biofilm forming and 40% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming isolates were positive for icaA gene production. In coagulase negative staph, 50% were positive biofilm forming and 50% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming strains were positive for icaA gene. All negative cases by CRA and microtiter plate methods were negative for icaA gene except two isolates. All staphylococcal isolates were subjected to antibiotic susceptibility test to correlate biofilm formation with multidrug resistance in staph.

CONCLUSION: There is high significant correlation between icaA gene presence and biofilm forming ability; however, the biofilm-forming ability of some isolates in the absence of icaA gene highlights the importance of further genetic investigations of ica-independent biofilm formation mechanisms.}, } @article {pmid30077168, year = {2018}, author = {Vergine, P and Salerno, C and Berardi, G and Pollice, A}, title = {Sludge cake and biofilm formation as valuable tools in wastewater treatment by coupling Integrated Fixed-film Activated Sludge (IFAS) with Self Forming Dynamic Membrane BioReactors (SFD-MBR).}, journal = {Bioresource technology}, volume = {268}, number = {}, pages = {121-127}, doi = {10.1016/j.biortech.2018.07.120}, pmid = {30077168}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Denitrification ; Membranes, Artificial ; *Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Two lab-scale Self Forming Dynamic Membrane BioReactors (SFD-MBR), equipped with 50 µm nylon meshes were set up and operated for the treatment of real municipal wastewater. Plastic carriers were added in one of the two bioreactors to generate a combination of the Integrated Fixed-film Activated Sludge (IFAS) and the SFD-MBR technologies. Overall, the two systems performed very well, achieving excellent effluent quality under steady state conditions and showing good resilience to extreme organic loading conditions. Continuous air scouring and periodical mesh cleaning by jet rinsing with tap water were effective in maintaining stable and high productivity (membrane flux around 67 L m[2] h[-1]) over a period of 140 days. The application of the IFAS process resulted in lower production of excess sludge and improved denitrification. On the other hand, under the tested conditions the combined IFAS-SFD-MBR showed a higher tendency to mesh clogging with respect to the SFD-MBR.}, } @article {pmid30077104, year = {2018}, author = {Zhou, L and Xu, X and Xia, S}, title = {Effects of sulfate on simultaneous nitrate and selenate removal in a hydrogen-based membrane biofilm reactor for groundwater treatment: Performance and biofilm microbial ecology.}, journal = {Chemosphere}, volume = {211}, number = {}, pages = {254-260}, doi = {10.1016/j.chemosphere.2018.07.092}, pmid = {30077104}, issn = {1879-1298}, mesh = {Biofilms/*drug effects ; Bioreactors/*microbiology ; Groundwater/*chemistry ; Hydrogen/*chemistry ; Nitrates/*chemistry ; Selenic Acid/*chemistry ; Sulfates/*chemistry ; }, abstract = {Effects of sulfate on simultaneous nitrate and selenate removal in a hydrogen-based membrane biofilm reactor (MBfR) for groundwater treatment was identified with performance and biofilm microbial ecology. In whole operation, MBfR had almost 100% removal of nitration even with 50 mg mL[-1] sulfate. Moreover, selenate degradation increased from 95% to approximate 100% with sulfate addition, indicating that sulfate had no obvious effects on nitrate degradation, and even partly promoted selenate removal. Short-term sulfate effect experiment further showed that Gibbs free energy of reduction (majority) and abiotic sulfide oxidation (especially between sulfate and selenate) contributed to degradable performance with sulfate. Microbial ecology showed that high percentage of Hydrogenophaga (≥75%) was one of the contributors for the stable and efficient nitrate degradation. Chemoheterotrophy (ratio>0.3) and dark hydrogen oxidation (ratio>0.3) were the majority of functional profile for biofilm in MBfR, and sulfate led to profiles of sulfate respiration and respiration of sulfur compounds in biofilm. Additionally, no special bacteria for selenate degradation was identified in biofilm microbial ecology, and selenate degradation was relied on Hydrogenophaga (75% of ecology percentage with sulfate addition) and Desulfovibrionaceae (4% of ecology percentage with sulfate addition). But with overloading sulfate, Desulfovibrionaceae was prior to sulfate degradation for energy supply and thus inhibited selenate removal.}, } @article {pmid30075862, year = {2019}, author = {Zhang, P and Chen, YP and Qiu, JH and Dai, YZ and Feng, B}, title = {Imaging the Microprocesses in Biofilm Matrices.}, journal = {Trends in biotechnology}, volume = {37}, number = {2}, pages = {214-226}, doi = {10.1016/j.tibtech.2018.07.006}, pmid = {30075862}, issn = {1879-3096}, mesh = {*Cell Adhesion ; Environmental Pollutants/analysis ; Extracellular Polymeric Substance Matrix/*chemistry ; *Metabolism ; Metabolome ; Optical Imaging/*methods ; }, abstract = {Biofilms, which are aggregates of microorganisms and extracellular matrices, widely colonize natural water bodies, wastewater treatment systems, and body tissues, and have vital roles in water purification, biofouling, and infectious diseases. Recently, multiple imaging modalities have been developed to visualize the morphological structure and material distribution within biofilms and to probe the microprocesses in biofilm matrices, including biofilm formation, transfer and metabolism of substrates, and cell-cell communication. These technologies have improved our understanding of biofilm control and the fates of substrates in biofilms. In this review, we describe the principles of various imaging techniques and discuss the advantages and limitations of each approach to characterizing microprocesses in biofilm matrices.}, } @article {pmid30074210, year = {2018}, author = {Wang, TM and Xie, XH and Li, K and Deng, YH and Chen, H}, title = {Alternative Oxidase Promotes Biofilm Formation of Candida albicans.}, journal = {Current medical science}, volume = {38}, number = {3}, pages = {443-448}, pmid = {30074210}, issn = {2523-899X}, mesh = {Biofilms/*growth & development ; Candida albicans/*enzymology/genetics/*physiology ; Electron Transport ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Genes, Fungal ; Mitochondrial Proteins/*metabolism ; Oxidoreductases/*metabolism ; Plant Proteins/*metabolism ; }, abstract = {This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans (C. albicans) on the biofilm formation. The 2, 3-bis (2-methoxy- 4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type (WT), GOA7-deleted (GOA31), GOAV-reconstituted (GOA32), AOXla-deleted (AOX1) and AOXlb-deleted (AOX2) C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECE1 and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex HI or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX1 strain, but the expression of ALSI and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOXla primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.}, } @article {pmid30073749, year = {2018}, author = {Bae, N and Park, HJ and Park, H and Kim, M and Han, SW}, title = {Deciphering the functions of the outer membrane porin OprBXo involved in virulence, motility, exopolysaccharide production, biofilm formation and stress tolerance in Xanthomonas oryzae pv. oryzae.}, journal = {Molecular plant pathology}, volume = {19}, number = {12}, pages = {2527-2542}, pmid = {30073749}, issn = {1364-3703}, mesh = {*Adaptation, Physiological/drug effects ; Amino Acid Sequence ; Bacterial Proteins/chemistry/*metabolism ; Biofilms/drug effects ; Chemotaxis/drug effects ; Hydrogen Peroxide/pharmacology ; *Movement ; Polysaccharides, Bacterial/*metabolism ; Porins/*metabolism ; Proteomics ; Sodium Dodecyl Sulfate/pharmacology ; *Stress, Physiological/drug effects ; Virulence/drug effects ; Xanthomonas/drug effects/*pathogenicity/*physiology ; }, abstract = {Xanthomonas oryzae pv. oryzae (Xoo) is a Gram-negative bacterium causing bacterial leaf blight disease in rice. Previously, proteomic analysis has shown that the outer membrane protein B in Xoo (OprBXo) is more abundant in the wildtype strain than is the outer membrane protein 1 in the Xoo (Omp1X) knockout mutant. OprBXo shows high homology with OprB, which has been well characterized as a carbohydrate-selective porin in X. citri ssp. citri and Pseudomonas species. However, the functions of OprBXo in Xoo have not yet been documented. To elucidate the functions of OprBXo, we generated the OprBXo-overexpressing mutant, Xoo(OprBXo), and the knockout mutant, XooΔoprBXo(EV). We found that the virulence and migration of Xoo(OprBXo), but not XooΔoprBXo(EV), were markedly reduced in rice. To postulate the mechanisms affected by OprBXo, comparative proteomic analysis was performed. Based on the results of proteomics, we employed diverse phenotypic assays to characterize the functions of OprBXo. Abnormal twitching motility and reduction in swarming motility were observed in Xoo(OprBXo). Moreover, Xoo(OprBXo) decreased, but XooΔoprBXo(EV) enhanced, exopolysaccharide production and biofilm formation. The chemotactic ability of XooΔoprBXo(EV) was dramatically lower than that of Xoo(EV) in the presence of glucose and xylose. Xoo(OprBXo) was resistant to sodium dodecylsulphate and hydrogen peroxide, but XooΔoprBXo(EV) was highly sensitive compared with Xoo(EV). Thus, OprBXo is not only essential for chemotaxis and stress tolerance, but also for motility, biofilm formation and exopolysaccharide production, which may contribute to the virulence of Xoo. These results will lead to new insights into the functions of a sugar-selective porin in Xoo.}, } @article {pmid30073039, year = {2018}, author = {Almeida, CA and Azevedo, MMB and Chaves, FCM and Roseo de Oliveira, M and Rodrigues, IA and Bizzo, HR and Gama, PE and Alviano, DS and Alviano, CS}, title = {Piper Essential Oils Inhibit Rhizopus oryzae Growth, Biofilm Formation, and Rhizopuspepsin Activity.}, journal = {The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale}, volume = {2018}, number = {}, pages = {5295619}, pmid = {30073039}, issn = {1712-9532}, abstract = {Piper is the largest genus of the Piperaceae family. The species of this genus have diverse biological activities and are used in pharmacopeia throughout the world. They are also used in folk medicine for treatment of many diseases in several countries including Brazil, China, India, Jamaica, and Mexico. In Brazil, Piper species are distributed throughout the national territory, making this genus a good candidate for biological activity screening. During our studies with Piper essential oils, we evaluated its activity against Rhizopus oryzae, the main agent of mucormycosis. The main compounds of seven Piper essential oils analyzed were Piper callosum-safrole (53.8%), P. aduncum-dillapiole (76.0%), P. hispidinervum-safrole (91.4%), P. marginatum-propiopiperone (13.2%), P. hispidum-γ-terpinene (30.9%), P. tuberculatum-(E)-caryophyllene (30.1%), and Piper sp.-linalool (14.6%). The minimum inhibitory concentration of Piper essential oils against R. oryzae ranged from 78.12 to >1250 μg/mL. The best result of total inhibition of biofilm formation was obtained with Piper sp. starting from 4.88 μg/mL. Considering the bioactive potential of EOs against planktonic cells and biofilm formation of R. oryzae could be of great interest for development of antimicrobials for therapeutic use in treatment of fungal infection.}, } @article {pmid30071459, year = {2018}, author = {Ooi, GTH and Tang, K and Chhetri, RK and Kaarsholm, KMS and Sundmark, K and Kragelund, C and Litty, K and Christensen, A and Lindholst, S and Sund, C and Christensson, M and Bester, K and Andersen, HR}, title = {Biological removal of pharmaceuticals from hospital wastewater in a pilot-scale staged moving bed biofilm reactor (MBBR) utilising nitrifying and denitrifying processes.}, journal = {Bioresource technology}, volume = {267}, number = {}, pages = {677-687}, doi = {10.1016/j.biortech.2018.07.077}, pmid = {30071459}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Denitrification ; *Hospitals ; Nitrification ; Pharmaceutical Preparations/*isolation & purification ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Hospital wastewater contains high concentrations of pharmaceuticals, which pose risks to receiving waters. In this study, a pilot plant consisting of six moving bed biofilm reactors (MBBRs) in series (with the intention to integrate Biological Oxygen Demand (BOD) removal, nitrification and denitrification as well as prepolishing Chemical Oxygen Demand (COD) for ozonation) was built to integrate pharmaceutical removal and intermittent feeding of the latter reactors aimed for micropollutant removal. Based on the experimental resultss, nitrifying MBBRs achieved higher removal as compared to denitrifying MBBRs except for azithromycin, clarithromycin, diatrizoic acid, propranolol and trimethoprim. In the batch experiments, nitrifying MBBRs showed the ability to remove most of the analysed pharmaceuticals, with degradation rate constants ranging from 5.0 × 10[-3] h[-1] to 2.6 h[-1]. In general, the highest degradation rate constants were observed in the nitrifying MBBRs while the latter MBBRs showed lower degradation rate constant. However, when the degradation rate constants were normalised to the respective biomass, the intermittently fed reactors presented the highest specific activity. Out of the 22 compounds studied, 17 compounds were removed with more than 20%.}, } @article {pmid30071451, year = {2018}, author = {Rekha, R and Vaseeharan, B and Ishwarya, R and Anjugam, M and S Alharbi, N and Kadaikunnan, S and Khaled, JM and Al-Anbr, MN and Govindarajan, M}, title = {Searching for crab-borne antimicrobial peptides: Crustin from Portunus pelagicus triggers biofilm inhibition and immune responses of Artemia salina against GFP tagged Vibrio parahaemolyticus Dahv2.}, journal = {Molecular immunology}, volume = {101}, number = {}, pages = {396-408}, doi = {10.1016/j.molimm.2018.07.024}, pmid = {30071451}, issn = {1872-9142}, mesh = {Agglutination Tests ; Animals ; Anti-Infective Agents/pharmacology ; Antimicrobial Cationic Peptides/chemistry/isolation & purification/*pharmacology ; Artemia/drug effects/*immunology/*microbiology ; Biofilms/*drug effects ; Brachyura/*chemistry ; Green Fluorescent Proteins/*metabolism ; Hemolymph/drug effects/metabolism ; Immunity/*drug effects ; Microbial Sensitivity Tests ; Monophenol Monooxygenase/metabolism ; Phagocytosis/drug effects ; Protein Structure, Secondary ; Saccharomyces cerevisiae/drug effects/metabolism ; Spectroscopy, Fourier Transform Infrared ; Survival Analysis ; Vibrio parahaemolyticus/drug effects/*physiology ; X-Ray Diffraction ; }, abstract = {Marine organisms represent a huge source of novel compounds for the development of effective antimicrobial drugs. The present study focus on the purification of the antimicrobial peptide crustin from the haemolymph of the blue swimmer crab, Portunus pelagicus, by blue Sepharose CL-6B matrix assisted affinity column chromatography. Crustin showed a single band with a molecular mass of 17 kDa in SDS-PAGE analysis. The XRD analysis exhibited peaks at 32° and 45° while a distinct peak with a retention time of 1.8 min resulted in high performance liquid chromatography (HPLC) pointing out the crystalline nature and purity of crustin, respectively. Crustin purified from P. pelagicus (Pp-Cru) showed immunological activities, triggering encapsulation, phagocytosis on Sepharose beads and yeast (Saccharomyces cerevisiae) respectively. Furthermore, encapsulation of GFP tagged V. parahaemolyticus in Artemia salina and challenging study were assessed under CLSM and the potential of Pp-Cru was examined in vivo. In addition, the growth reduction and biofilm inhibition potential of Pp-Cru on Staphylococcus aureus, Enterococcus faecalis (Gram- positive bacteria) and Pseudomonas aeruginosa, Escherichia coli (Gram-negative bacteria) was evidenced by inverted and confocal laser scanning microscopic analysis, revealing that 100 μg/ml of Pp-Cru can disrupt the biofilm matrix thereby the thickness of biofilm was significantly reduced. Overall, the present investigation might provide a sensitive platform to realize the significant function of Pp-Cru in crustacean immune mechanism as well as its potential to bacterial growth inhibitor. The functional properties of purified Pp-Cru antimicrobial peptide may lead to a superior understanding of innate immune response in P. pelagicus species, which suggest the promising application for drug development in aquaculture.}, } @article {pmid30070706, year = {2019}, author = {Souza, JGS and Cury, JA and Ricomini Filho, AP and Feres, M and Faveri, M and Barão, VAR}, title = {Effect of sucrose on biofilm formed in situ on titanium material.}, journal = {Journal of periodontology}, volume = {90}, number = {2}, pages = {141-148}, doi = {10.1002/JPER.18-0219}, pmid = {30070706}, issn = {1943-3670}, mesh = {Biofilms ; Cross-Over Studies ; Dental Enamel ; Humans ; Streptococcus mutans ; *Sucrose ; *Titanium ; }, abstract = {BACKGROUND: Because sucrose may change the composition of biofilms formed on dental surfaces, the aim of this study was to evaluate in situ the effect of this dietary sugar on biofilm formation on titanium surface.

METHODS: In this blind, crossover, in situ study, 10 volunteers wore, in 3 phases of 7 days each, a palatal appliance containing titanium specimens. In each phase, the specimens were treated extraorally with 20% sucrose solution at a frequency of 4 or 8 times per day. As control, no treatment was rendered (0×). At the end of each phase, the biofilms were collected for biochemical analysis of biofilm wet weight (biomass), protein concentration, soluble (S-EPS), and insoluble (I-EPS) extracellular polysaccharides and intracellular polysaccharides (IPS), and for microbiologic analysis by checkerboard DNA-DNA hybridization (for levels and proportions of 40 bacterial species). Biochemical data were analyzed by linear regression and microbiological findings by Friedman and Dunn tests (α = .05).

RESULTS: A positive significant linear relationship was found among sucrose exposure (0×, 4×, and 8×) and biomass, S-EPS, I-EPS and IPS (p < 0.05). The biofilms treated with sucrose (4× and/or 8×) presented higher mean total levels of the 40 bacterial species evaluated, higher proportions of red complex species and lower proportions of the host-compatible green complex species, in comparison with the control group (p < 0.05).

CONCLUSION: The findings of the present study suggest that daily sucrose exposure has a harmful effect on the composition of biofilms formed on titanium surfaces.}, } @article {pmid30070287, year = {2018}, author = {Kuppusamy, R and Yasir, M and Yee, E and Willcox, M and Black, DS and Kumar, N}, title = {Guanidine functionalized anthranilamides as effective antibacterials with biofilm disruption activity.}, journal = {Organic & biomolecular chemistry}, volume = {16}, number = {32}, pages = {5871-5888}, doi = {10.1039/c8ob01699b}, pmid = {30070287}, issn = {1477-0539}, abstract = {We describe a library of amphiphilic anthranilamide compounds as antimicrobial peptide (AMP) mimics. These contain a hydrophobic naphthoyl side chain and different hydrophilic cationic groups such as amino, quaternary ammonium and guanidino groups. These are prepared via the ring-opening of different isatoic anhydrides. The antibacterial activity against S. aureus and E. coli of compounds containing guanidino cationic groups was greater than that for amino and quaternary ammonium cationic groups. The fluoro-substituted guanidinium compound 9b showed a minimum inhibitory concentration (MIC) of 2.0 μM against S. aureus, and reduced established biofilms of S. aureus by 92% at 64 μM concentration. The bromo-substituted guanidinium compound 9d exhibited good MIC against S. aureus (3.9 μM) and E. coli (15.6 μM) and disrupted established biofilms of S. aureus by 83% at 62.4 μM concentration. Cytoplasmic membrane permeability studies suggested that depolarization and disruption of the bacterial cell membrane could be a possible mechanism for antibacterial activity and the in vitro toxicity studies against MRC-5 human lung fibroblast cells showed that the potent compounds are non-toxic against mammalian cells.}, } @article {pmid30070146, year = {2018}, author = {Konieczka, P and Nowicka, K and Madar, M and Taciak, M and Smulikowska, S}, title = {Effects of pea extrusion and enzyme and probiotic supplementation on performance, microbiota activity and biofilm formation in the broiler gastrointestinal tract.}, journal = {British poultry science}, volume = {59}, number = {6}, pages = {654-662}, doi = {10.1080/00071668.2018.1507017}, pmid = {30070146}, issn = {1466-1799}, mesh = {Animal Feed ; Animals ; Bacillus subtilis/physiology ; Biofilms/*growth & development ; Chickens/*microbiology/*physiology ; Diet/veterinary ; Female ; Gastrointestinal Tract/microbiology ; Glycoside Hydrolases/*administration & dosage ; Microbiota/physiology ; *Peas/chemistry ; Probiotics/*administration & dosage ; Seeds/chemistry ; Soybeans ; Triticum ; }, abstract = {1. The effects of supplementation of broiler chicken diets with pea meal, carbohydrase enzymes and a probiotic were investigated for potential performance improvement. 2. Raw or extruded pea meal (cv Model, grown in Poland) was included in a wheat-soybean meal-based diet at 250 g/kg. The diets were unsupplemented (control) or supplemented with either carbohydrase enzymes (200 U/kg xylanase and 10 U/kg β-glucanase in feed) or a probiotic (Bacillus subtilis), or both. The diets were fed to Ross 308 broilers aged 9-28 days. 3. After two additional days, chick gastrointestinal tracts were excised and analysed for the presence of Bacillus subtilis biofilm; and the ileal and caecal digesta were analysed for bacterial enzyme activities and to determine the concentration of short-chain fatty acids (SCFAs). 4. Feeding the pea-based diet supplemented with the probiotic compromised feed utilisation, due to higher feed intake. The addition of enzymes to the raw, but not the extruded, pea containing diet partially ameliorated this effect (pea form × additives; P < 0.002). 5. In the ileal digesta, interactions between the dietary treatments were observed for the activities of all bacterial glycolytic enzymes and for SCFA concentrations. β-glucosidase, α-galactosidase and β-glucuronidase were highest in birds fed the diet containing extruded pea supplemented with the probiotic and enzymes (pea form x additives; P = 0.018 to P < 0.006). In the caecal digesta, interactions were observed for bacterial enzyme activities, but not for total SCFA concentration. Biofilm formation in the caecum indicated that the probiotic strain was metabolically active in the broiler gut. 6. In conclusion, supplementation of diets containing raw or extruded pea meal with enzymes and a Bacillus subtilis spore-based probiotic modulated microbiota activity but had no clear effects on broiler performance. Probiotic administration did not cause excessive fermentation in the ileum and caecum but enhanced Bacillus subtilis spp. biofilm formation in the caecum, which may be indicative of a beneficial effect on gut health.}, } @article {pmid30069474, year = {2018}, author = {Woo, SH and Lee, SM and Park, KC and Park, GN and Cho, B and Kim, I and Kim, J and Hong, S}, title = {Effects of Fine Particulate Matter on Pseudomonas aeruginosa Adhesion and Biofilm Formation In Vitro.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {6287932}, pmid = {30069474}, issn = {2314-6141}, mesh = {Bacterial Adhesion ; *Biofilms ; Epithelial Cells ; Humans ; Particulate Matter/*pharmacology ; *Pseudomonas aeruginosa ; }, abstract = {Respiratory infections of Pseudomonas aeruginosa are a major cause of mortality and morbidity for hospitalized patients. Fine particulate matter (FPM) is known to have interactions with some bacterial infection in the respiratory system. In this report, we investigate the effect of different concentration of FPM on P. aeruginosa attachment and biofilm formation using in vitro cell culture systems. P. aeruginosa were cultured to form mature biofilms on hydroxyapatite-coated peg and the number of bacteria in the biofilms was enumerated. Morphology of biofilm was imaged with scanning electron microscopy and confocal laser scanning microscopy. Bacterial affinity change to the cell membrane was evaluated with attached colony counting and fluorescence microscopy images. Alteration of bacterial surface hydrophobicity and S100A4 protein concentration were explored as mechanisms of P. aeruginosa adhesion to human cells. There were a concentration-dependent increase of thickness and surface roughness of biofilm mass. P. aeruginosa adherence to respiratory epithelial cells was increased after FPM treatment. Bacterial surface hydrophobicity and S1000A4 protein concentration were increased with proportionally the dose of FPM in media. FPM in the airway could enhance both the adhesion of P. aeruginosa to epithelial cells and biofilm formation. Bacterial surface hydrophobicity and human cell plasma membrane injury are associated with binding of P. aeruginosa on airway epithelial cells and biofilm formation.}, } @article {pmid30068935, year = {2018}, author = {Garcia, C and Burgain, A and Chaillot, J and Pic, É and Khemiri, I and Sellam, A}, title = {A phenotypic small-molecule screen identifies halogenated salicylanilides as inhibitors of fungal morphogenesis, biofilm formation and host cell invasion.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {11559}, pmid = {30068935}, issn = {2045-2322}, support = {Établissement de jeunes chercheurs//Fonds de Recherche du Québec - Santé (Fonds de la recherche en sante du Quebec)/International ; J1 salary award//Fonds de Recherche du Québec - Santé (Fonds de la recherche en sante du Quebec)/International ; Discovery grant #06625//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/International ; CFI- # 34171//Canada Foundation for Innovation (Fondation canadienne pour l'innovation)/International ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Candida/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development ; *Drug Evaluation, Preclinical ; Endocytosis/drug effects ; Epithelial Cells/microbiology ; Gene Expression Profiling ; HT29 Cells ; Humans ; Hyphae/drug effects/growth & development ; Morphogenesis ; Salicylanilides/*pharmacology ; Virulence/drug effects ; }, abstract = {A poorly exploited paradigm in the antimicrobial therapy field is to target virulence traits for drug development. In contrast to target-focused approaches, antivirulence phenotypic screens enable identification of bioactive molecules that induce a desirable biological readout without making a priori assumption about the cellular target. Here, we screened a chemical library of 678 small molecules against the invasive hyphal growth of the human opportunistic yeast Candida albicans. We found that a halogenated salicylanilide (N1-(3,5-dichlorophenyl)-5-chloro-2-hydroxybenzamide) and one of its analogs, Niclosamide, an FDA-approved anthelmintic in humans, exhibited both antifilamentation and antibiofilm activities against C. albicans and the multi-resistant yeast C. auris. The antivirulence activity of halogenated salicylanilides were also expanded to C. albicans resistant strains with different resistance mechanisms. We also found that Niclosamide protected the intestinal epithelial cells against invasion by C. albicans. Transcriptional profiling of C. albicans challenged with Niclosamide exhibited a signature that is characteristic of the mitochondria-to-nucleus retrograde response. Our chemogenomic analysis showed that halogenated salicylanilides compromise the potential-dependant mitochondrial protein translocon machinery. Given the fact that the safety of Niclosamide is well established in humans, this molecule could represent the first clinically approved antivirulence agent against a pathogenic fungus.}, } @article {pmid30067078, year = {2018}, author = {Marchese, A and Arciola, CR and Coppo, E and Barbieri, R and Barreca, D and Chebaibi, S and Sobarzo-Sánchez, E and Nabavi, SF and Nabavi, SM and Daglia, M}, title = {The natural plant compound carvacrol as an antimicrobial and anti-biofilm agent: mechanisms, synergies and bio-inspired anti-infective materials.}, journal = {Biofouling}, volume = {34}, number = {6}, pages = {630-656}, doi = {10.1080/08927014.2018.1480756}, pmid = {30067078}, issn = {1029-2454}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cymenes ; Humans ; Monoterpenes/*pharmacology ; }, abstract = {Carvacrol (5-isopropyl-2-methyl phenol) is a natural compound that occurs in the leaves of a number of plants and herbs including wild bergamot, thyme and pepperwort, but which is most abundant in oregano. The aim of this review is to analyse the scientific data from the last five years (2012-2017) on the antimicrobial and anti-biofilm activities of carvacrol, targeting different bacteria and fungi responsible for human infectious diseases. The antimicrobial and anti-biofilm mechanisms of carvacrol and its synergies with antibiotics are illustrated. The potential of carvacrol-loaded anti-infective nanomaterials is underlined. Carvacrol shows excellent antimicrobial and anti-biofilm activities, and is a very interesting bioactive compound against fungi and a wide range of Gram-positive and Gram-negative bacteria, and being active against both planktonic and sessile human pathogens. Moreover, carvacrol lends itself to being combined with nanomaterials, thus providing an opportunity for preventing biofilm-associated infections by new bio-inspired, anti-infective materials.}, } @article {pmid30066983, year = {2018}, author = {Obuobi, S and Wang, Y and Khara, JS and Riegger, A and Kuan, SL and Ee, PLR}, title = {Antimicrobial and Anti-Biofilm Activities of Surface Engineered Polycationic Albumin Nanoparticles with Reduced Hemolytic Activity.}, journal = {Macromolecular bioscience}, volume = {18}, number = {10}, pages = {e1800196}, doi = {10.1002/mabi.201800196}, pmid = {30066983}, issn = {1616-5195}, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Bacteria/*growth & development ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Erythrocytes/cytology/*metabolism ; Hemolysis/*drug effects ; Humans ; Nanoparticles/*chemistry ; Polyethylene Glycols/chemistry ; *Serum Albumin, Human/chemistry/pharmacology ; }, abstract = {Protein-based polymeric polyelectrolytes are emerging as alternative synthetic nanoparticles owing to their biodegradability and biocompatibility. However, potential in vivo toxicity remains a significant challenge. Herein an array of protein polyelectrolytes generated from cationic human serum albumin (cHSA) and polyethylene glycol (PEG) are synthesized via synthetic customization as antimicrobials for the treatment of systemic infections. By varying PEG molecular weight and chain length, in vitro hemolytic activity can be fine-tuned without significantly affecting antimicrobial potency. The optimal hybrid material, PEG (2000)18 -cHSA, with potent antimicrobial character, low hemolytic activity, and in vitro biofilm disruptive properties is identified. Surface plasmon resonance (SPR) evaluation demonstrates significantly higher binding activity of the protein nanoparticles to bacteria cell wall components and microfluidic live-cell imaging indicates that the nanoparticles act through a membranolytic mechanism. Given their low susceptibility to drug resistance and potent activity against resistant bacteria strains, these findings establish the PEGylated albumin nanoparticles as a potent weaponry against drug resistance and biofilm-related infection.}, } @article {pmid30066753, year = {2018}, author = {Santos, ALSD and Galdino, ACM and Mello, TP and Ramos, LS and Branquinha, MH and Bolognese, AM and Columbano Neto, J and Roudbary, M}, title = {What are the advantages of living in a community? A microbial biofilm perspective!.}, journal = {Memorias do Instituto Oswaldo Cruz}, volume = {113}, number = {9}, pages = {e180212}, pmid = {30066753}, issn = {1678-8060}, mesh = {*Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Environmental Microbiology ; Fungi/*physiology ; Humans ; }, abstract = {Biofilm formation is the preferred mode of growth lifestyle for many microorganisms, including bacterial and fungal human pathogens. Biofilm is a strong and dynamic structure that confers a broad range of advantages to its members, such as adhesion/cohesion capabilities, mechanical properties, nutritional sources, metabolite exchange platform, cellular communication, protection and resistance to drugs (e.g., antimicrobials, antiseptics, and disinfectants), environmental stresses (e.g., dehydration and ultraviolet light), host immune attacks (e.g., antibodies, complement system, antimicrobial peptides, and phagocytes), and shear forces. Microbial biofilms cause problems in the hospital environment, generating high healthcare costs and prolonged patient stay, which can result in further secondary microbial infections and various health complications. Consequently, both public and private investments must be made to ensure better patient management, as well as to find novel therapeutic strategies to circumvent the resistance and resilience profiles arising from biofilm-associated microbial infections. In this work, we present a general overview of microbial biofilm formation and its relevance within the biomedical context.}, } @article {pmid30065702, year = {2018}, author = {Rehman, ZU and Leiknes, T}, title = {Quorum-Quenching Bacteria Isolated From Red Sea Sediments Reduce Biofilm Formation by Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1354}, pmid = {30065702}, issn = {1664-302X}, abstract = {Quorum sensing (QS) is the process by which bacteria communicate with each other through small signaling molecules such as N-acylhomoserine lactones (AHLs). Certain bacteria can degrade AHL molecules by a process called quorum quenching (QQ); therefore, QQ can be used to control bacterial infections and biofilm formation. In this study, we aimed to identify new species of bacteria with QQ activity. Red Sea sediments were collected either from the close vicinity of seagrass or from areas with no vegetation. We isolated 72 bacterial strains, which were tested for their ability to degrade/inactivate AHL molecules. Chromobacterium violaceum CV026-based bioassay was used for the initial screening of isolates with QQ activity. QQ activity was further quantified using high-performance liquid chromatography-tandem mass spectrometry. We found that these isolates could degrade AHL molecules of different acyl chain lengths as well as modifications. 16S-rRNA sequencing of positive QQ isolates showed that they belonged to three different genera. Specifically, two isolates belonged to the genus Erythrobacter; four, Labrenzia; and one, Bacterioplanes. The genome of one representative isolate from each genus was sequenced, and potential QQ enzymes, namely, lactonases and acylases, were identified. The ability of these isolates to degrade the 3OXOC12-AHLs produced by Pseudomonas aeruginosa PAO1 and hence inhibit biofilm formation was investigated. Our results showed that the isolate VG12 (genus Labrenzia) is better than other isolates at controlling biofilm formation by PAO1 and degradation of different AHL molecules. Time-course experiments to study AHL degradation showed that VG1 (genus Erythrobacter) could degrade AHLs faster than other isolates. Thus, QQ bacteria or enzymes can be used in combination with an antibacterial to overcome antibiotic resistance.}, } @article {pmid30062880, year = {2018}, author = {Funari, R and Bhalla, N and Chu, KY and Söderström, B and Shen, AQ}, title = {Nanoplasmonics for Real-Time and Label-Free Monitoring of Microbial Biofilm Formation.}, journal = {ACS sensors}, volume = {3}, number = {8}, pages = {1499-1509}, doi = {10.1021/acssensors.8b00287}, pmid = {30062880}, issn = {2379-3694}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Biosensing Techniques/*methods ; Escherichia coli/drug effects/*physiology ; Kanamycin/pharmacology ; Nanostructures/*chemistry ; Point-of-Care Systems ; Surface Plasmon Resonance ; }, abstract = {Microbial biofilms possess intrinsic resistance against conventional antibiotics and cleaning procedures; thus, a better understanding of their complex biological structures is crucial in both medical and industrial applications. Existing laboratory methodologies have focused on macroscopic and mostly indirect characterization of mechanical and microbiological properties of biofilms adhered on a given substrate. However, the kinetics underlying the biofilm formation is not well understood, while such information is critical to understanding how drugs and chemicals influence the biofilm formation. Herein, we report the use of localized surface plasmon resonance (LSPR) for real-time, label-free monitoring of E. coli biofilm assembly on a nanoplasmonic substrate consisting of gold mushroom-like structures. Our LSPR sensor is able to capture the signatures of biofilm formation in real-time by measuring the wavelength shift in the LSPR resonance peak with high temporal resolution. We employ this sensor feature to elucidate how biofilm formation is affected by different drugs, including conventional antibiotics (kanamycin and ampicillin) as well as rifapentine, a molecule preventing cell adhesion yet barely affecting bacterial viability and vitality. Due to its flexibility and simplicity, our LSPR based platform can be used on a wide variety of clinically relevant bacteria, thus representing a valuable tool in biofilm characterization and drug screening.}, } @article {pmid30062620, year = {2019}, author = {Paldrychová, M and Kolouchová, I and Vaňková, E and Maťátková, O and Šmidrkal, J and Krmela, A and Schulzová, V and Hajšlová, J and Masák, J}, title = {Effect of resveratrol and Regrapex-R-forte on Trichosporon cutaneum biofilm.}, journal = {Folia microbiologica}, volume = {64}, number = {1}, pages = {73-81}, pmid = {30062620}, issn = {1874-9356}, support = {17-15936S//Grantová Agentura České Republiky/ ; CZ.2.16/3.1.00/24503//Operational Programme Prague - Competitiveness/ ; NPU I (LO1601 - No.: MSMT-43760/2015)//National Program of Sustainability I/ ; }, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Fallopia japonica/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Resveratrol/*pharmacology ; Trichosporon/*drug effects/growth & development/metabolism ; Vitis/chemistry ; }, abstract = {Microorganisms that cause chronic infections exist predominantly as surface-attached stable communities known as biofilms. Microbial cells in biofilms are highly resistant to conventional antibiotics and other forms of antimicrobial treatment; therefore, modern medicine tries to develop new drugs that exhibit anti-biofilm activity. We investigated the influence of a plant polyphenolic compound resveratrol (representative of the stilbene family) on the opportunistic pathogen Trichosporon cutaneum. Besides the influence on the planktonic cells of T. cutaneum, the ability to inhibit biofilm formation and to eradicate mature biofilm was studied. We have tested resveratrol as pure compound, as well as resveratrol in complex plant extract-the commercially available dietary supplement Regrapex-R-forte, which contains the extract of Vitis vinifera grape and extract of Polygonum cuspidatum root. Regrapex-R-forte is rich in stilbenes and other biologically active substances. Light microscopy imaging, confocal microscopy, and crystal violet staining were used to quantify and visualize the biofilm. The metabolic activity of biofilm-forming cells was studied by the tetrazolium salt assay. Amphotericin B had higher activity against planktonic cells; however, resveratrol and Regrapex-R-forte showed anti-biofilm effects, both in inhibition of biofilm formation and in the eradication of mature biofilm. The minimum biofilm eradicating concentration (MBEC80) for Regrapex-R-forte was found to be 2222 mg/L (in which resveratrol concentration is 200 mg/L). These methods demonstrated that Regrapex-R-forte can be employed as an anti-biofilm agent, as it has similar effect as amphotericin B (MBEC80 = 700 mg/L), which is routinely used in clinical practice.}, } @article {pmid30062140, year = {2018}, author = {Abi Hachem, R and Goncalves, S and Walker, T and Angeli, S}, title = {Middle ear irrigation using a hydrodebrider decreases biofilm surface area in an animal model of otitis media.}, journal = {Laryngoscope investigative otolaryngology}, volume = {3}, number = {3}, pages = {231-237}, pmid = {30062140}, issn = {2378-8038}, abstract = {OBJECTIVE: To compare the safety and efficacy of manual and powered irrigation of the middle ear using saline or 1% baby shampoo to treat biofilm-forming bacterial middle ear infections.

BACKGROUND: Biofilms play a major role in recalcitrant otitis media and are challenging to treat. Many therapeutic strategies have been attempted and the role of topical therapies is still being investigated. Topical irrigation using saline or 1% baby shampoo and the use of a hydrodebrider have been investigated in biofilms involved in chronic rhinosinusitis and their role within the middle ear is yet to be determined.

METHODS: Twenty-two adult chinchillas underwent bilateral trans-bullar inoculation of non-typable biofilm forming Haemophilus influenza followed by unilateral middle ear irrigation 5 days later using saline administered via a powered hydrodebrider or manual irrigation of saline or 1% baby shampoo. Contralateral inoculated ears served as control and were not irrigated. Two days following irrigation, the bullae were harvested and processed for scanning electron microscopy to assess biofilm surface area. Auditory brainstem responses were performed before bacterial inoculation and prior to euthanasia.

RESULTS: Manual and powered irrigation were effective in reducing the surface area of biofilm when compared to the control group. The hydrodebrider demonstrated to be more effective at eradicating biofilm than manual irrigation, especially in areas of difficult access, such as the ventral portion of the chinchillas' bullae. There was no difference in manual irrigation of saline when compared to 1% baby shampoo. Irrigations either manually or using the hydrodebrider did not affect hearing, the vestibular system or facial function.

CONCLUSION: Middle ear biofilms can be treated safely and effectively with rinses using either normal saline or 1% baby shampoo administered manually or with a powered hydrodebrider.

LEVEL OF EVIDENCE: NA.}, } @article {pmid30061756, year = {2018}, author = {Kent, AG and Garcia, CA and Martiny, AC}, title = {Increased biofilm formation due to high-temperature adaptation in marine Roseobacter.}, journal = {Nature microbiology}, volume = {3}, number = {9}, pages = {989-995}, pmid = {30061756}, issn = {2058-5276}, support = {NNX15AN56H//NASA/United States ; T32 EB009418/EB/NIBIB NIH HHS/United States ; }, mesh = {Acclimatization/*physiology ; Anaerobiosis ; Aquatic Organisms/growth & development/physiology ; Biofilms/*growth & development ; Climate Change ; Escherichia coli/genetics/*growth & development/*physiology ; Genetic Variation/genetics ; Genome, Bacterial/genetics ; *Hot Temperature ; Oceans and Seas ; Oxygen/metabolism ; Roseobacter/genetics/*growth & development/*physiology ; }, abstract = {Ocean temperatures will increase significantly over the next 100 years due to global climate change[1]. As temperatures increase beyond current ranges, it is unclear how adaptation will impact the distribution and ecological role of marine microorganisms[2]. To address this major unknown, we imposed a stressful high-temperature regime for 500 generations on a strain from the abundant marine Roseobacter clade. High-temperature-adapted isolates significantly improved their fitness but also increased biofilm formation at the air-liquid interface. Furthermore, this altered lifestyle was coupled with genomic changes linked to biofilm formation in individual isolates, and was also dominant in evolved populations. We hypothesize that the increasing biofilm formation was driven by lower oxygen availability at elevated temperature, and we observe a relative fitness increase at lower oxygen. The response is uniquely different from that of Escherichia coli adapted to high temperature[3] (only 3% of mutated genes were shared in both studies). Thus, future increased temperatures could have a direct effect on organismal physiology and an indirect effect via a decrease in ocean oxygen solubility, leading to an alteration in microbial lifestyle.}, } @article {pmid30061582, year = {2018}, author = {Takimoto, Y and Hatamoto, M and Ishida, T and Watari, T and Yamaguchi, T}, title = {Fouling Development in A/O-MBR under Low Organic Loading Condition and Identification of Key Bacteria for Biofilm Formations.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {11427}, pmid = {30061582}, issn = {2045-2322}, mesh = {Aerobiosis ; Anaerobiosis ; Bacteria/*metabolism ; Biofilms/*growth & development ; *Biofouling ; Bioreactors/*microbiology ; Organic Chemicals/*analysis ; Principal Component Analysis ; Wastewater/chemistry/microbiology ; }, abstract = {Membrane fouling in membrane bioreactors (MBR) remains a major issue and knowledge of microbes associated with biofilm formation might facilitate the control of this phenomenon, Thus, an anoxic/oxic membrane bioreactor (A/O-MBR) was operated under an extremely low organic loading rate (0.002 kg-COD·m[-3]·day[-1]) to induce membrane fouling and the major biofilm-forming bacteria were identified. After operation under extremely low organic loading condition, the reactor showed accumulation of total nitrogen and phosphorus along with biofilm development on the membrane surface. Thus, membrane fouling induced by microbial cell lysis was considered to have occurred. Although no major changes were observed in the microbial community structure of the activated sludge in the MBR before and after membrane fouling, uncultured bacteria were specifically increased in the biofilm. Therefore, bacteria belonging to candidate phyla including TM6, OD1 and Gammaproteobacteria could be important biofilm-forming bacteria.}, } @article {pmid30060425, year = {2018}, author = {Yang, JX and Zhao, B and An, Q and Huang, YS and Guo, JS}, title = {Bioaugmentation with A. faecalis strain NR for achieving simultaneous nitrogen and organic carbon removal in a biofilm reactor.}, journal = {Bioresource technology}, volume = {247}, number = {}, pages = {871-880}, doi = {10.1016/j.biortech.2017.09.189}, pmid = {30060425}, issn = {1873-2976}, mesh = {*Alcaligenaceae ; *Biofilms ; Bioreactors ; *Carbon ; *Nitrogen ; Sewage ; Waste Disposal, Fluid ; }, abstract = {The dynamics model of Alcaligenes faecalis NR was combined with the activated sludge model No. 1 to guide how to make the bioaugmentation of strain NR successful. Model studies show that conventional heterotrophic bacteria in activated sludge always outcompete strain NR. The competition between strain NR and Nitrosomonas, a typical ammonium-oxidizing bacterium (AOB), mainly depends on COD concentration and maximum growth rate of Nitrosomonas. 2000mg/L of COD ensures that strain NR is always able to outcompete AOB. A biofilm reactor was developed to avoid a quick decrease in influent substrates. Approximately 94.2% of TN and 93.6% of COD were removed in the bioaugmented biofilm reactor, showing much better performance than an identical biofilm reactor without strain NR inoculation. A long-term experiment showed that strain NR successfully proliferated in the bioaugmented reactor. The abundance variation of strain NR mainly depended on influent COD concentrations, which was consistent with the model results.}, } @article {pmid30059945, year = {2018}, author = {Wang, HJ and Dai, K and Wang, YQ and Wang, HF and Zhang, F and Zeng, RJ}, title = {Mixed culture fermentation of synthesis gas in the microfiltration and ultrafiltration hollow-fiber membrane biofilm reactors.}, journal = {Bioresource technology}, volume = {267}, number = {}, pages = {650-656}, doi = {10.1016/j.biortech.2018.07.098}, pmid = {30059945}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Clostridium ; *Fermentation ; Ultrafiltration ; }, abstract = {The effects of pore sizes on the in-situ utilization of synthesis gas (syngas, H2 and CO) mixed culture fermentation (MCF) in the hollow-fiber membrane biofilm reactor (HfMBR) are not clear. Thus, the ultrafiltration (R1) and microfiltration (R2) HfMBRs were constructed. Syngas was totally consumed within the formed biofilm in R1; contrarily, it accumulated notably in R2. In the batch mode of R1 and R2, volatile fatty acids (VFAs) of acetate, butyrate and caproate were the main metabolites, but the production rate of total VFA in R1 (61.9 mmol-C/(L·d)) was higher than that of R2 (27.6 mmol-C/(L·d)). In the continuous mode, the R1 performance was much better than that of R2, and the biofilm in R2 was even washed out. Furthermore, Clostridium (30.0%) was the main genus in the enriched biofilm of R1, which converted syngas to VFAs. Thus, the ultrafiltration membrane shall be the suitable candidate for syngas MCF.}, } @article {pmid30059921, year = {2019}, author = {Jiang, Y and Khan, A and Huang, H and Tian, Y and Yu, X and Xu, Q and Mou, L and Lv, J and Zhang, P and Liu, P and Deng, L and Li, X}, title = {Using nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as biofilm support enhances oil-refinery wastewater treatment in a biofilm membrane bioreactor.}, journal = {The Science of the total environment}, volume = {646}, number = {}, pages = {606-617}, doi = {10.1016/j.scitotenv.2018.07.149}, pmid = {30059921}, issn = {1879-1026}, mesh = {Biofilms/growth & development ; Bioreactors/*microbiology ; Clay/chemistry ; Magnesium Compounds/*chemistry ; Membranes, Artificial ; Silicon Compounds/*chemistry ; Urethane/*chemistry ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry/microbiology ; Water Purification ; }, abstract = {Petroleum refinery wastewater (PRW) treatments based on biofilm membrane bioreactor (BF-MBR) technology is an ideal approach and biofilm supporting material is a critical factor. In this study, BF-MBR with nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as a biofilm support was used to treat PRW with a hydraulic retention time of 5 h. The removal rate of 500 mg/L chemical oxygen demand (COD), 15 mg/L NH4[+] and 180 NTU of turbidity were 99.73%, 97.48% and 99.99%, which were 23%, 20%, and 6% higher than in the control bioreactor, respectively. These results were comparatively higher than that observed for the sequencing batch reactor (SBR). The death rate of the Spirodela polyrrhiza (L.) irrigated with BF-MBR-treated water was 4.44%, which was similar to that of the plants irrigated with tap water (3.33%) and SBR-treated water (5.56%), but significantly lower than that irrigated with raw water (84.44%). The counts demonstrated by qPCR for total bacteria, denitrifiers, nitrite oxidizing bacteria, ammonia oxidizing bacteria, and ammonia-oxidizing archaea were also higher in BF-MBR than those obtained by SBR. Moreover, the results of 16 s rRNA sequencing have demonstrated that the wastewater remediation microbes were enriched in AT/HUFs, e.g., Acidovorax can degrade polycyclic aromatic hydrocarbons, and Sulfuritalea is an efficient nitrite degrader. In summary, BF-MBR using AT/HUF as a biofilm support improves microbiome of the actived sludge and is reliable for oil-refinery wastewater treatment.}, } @article {pmid30058521, year = {2018}, author = {Hussain, M and Fisher, E and Fishman, J}, title = {Bacterial biofilm and chronic sialadenitis, survival outcomes in human papilloma virus positive oral cancer, and long-term use of trimethoprim/sulfamethoxazole in recalcitrant chronic rhinosinusitis.}, journal = {The Journal of laryngology and otology}, volume = {132}, number = {7}, pages = {567}, doi = {10.1017/S0022215118001238}, pmid = {30058521}, issn = {1748-5460}, mesh = {Humans ; Otorhinolaryngologic Diseases/*therapy ; }, } @article {pmid30057443, year = {2018}, author = {Algburi, A and Zehm, S and Netrebov, V and Weeks, R and Zubovskiy, K and Chikindas, ML}, title = {Benzoyl Peroxide Inhibits Quorum Sensing and Biofilm Formation by Gardnerella vaginalis 14018.}, journal = {Infectious diseases in obstetrics and gynecology}, volume = {2018}, number = {}, pages = {1426109}, pmid = {30057443}, issn = {1098-0997}, mesh = {Anti-Bacterial Agents/*pharmacology ; Benzoyl Peroxide/*pharmacology ; Biofilms/*drug effects ; Female ; Gardnerella vaginalis/*drug effects/physiology ; Humans ; Quorum Sensing/*drug effects ; Salicylic Acid/pharmacology ; Vaginosis, Bacterial/drug therapy ; }, abstract = {Infection recurrence and antibiotic resistance of bacterial vaginosis-associated pathogenic biofilms underline the need for novel and effective treatment strategies. In this study, we evaluated the antimicrobial, antibiofilm, and quorum sensing inhibitory effects of benzoyl peroxide and salicylic acid against Gardnerella vaginalis ATCC 14018, the predominant pathogen of bacterial vaginosis. While the highest tested concentrations of 250 and 125 μg/mL for both compounds were not sufficient in completely inhibiting the growth of G. vaginalis ATCC 14018, they did prevent biofilm formation by inhibiting the bacterial quorum sensing system in the pathogen. To our knowledge, this report is the first evidence that benzoyl peroxide can have a quorum sensing-mediated biofilm controlling effect, as demonstrated using subinhibitory concentrations of this compound in order to reduce the cost, dosage, and negative side effects associated with current antimicrobial treatments.}, } @article {pmid30057356, year = {2018}, author = {Paraje, MG}, title = {[Persist and triumph: persistent cells in microbial biofilm].}, journal = {Revista Argentina de microbiologia}, volume = {50}, number = {3}, pages = {231-233}, doi = {10.1016/j.ram.2018.07.001}, pmid = {30057356}, issn = {0325-7541}, mesh = {Bacteria ; *Biofilms ; }, } @article {pmid30057355, year = {2018}, author = {Mohammed, YHE and Manukumar, HM and Rakesh, KP and Karthik, CS and Mallu, P and Qin, HL}, title = {Vision for medicine: Staphylococcus aureus biofilm war and unlocking key's for anti-biofilm drug development.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {339-347}, doi = {10.1016/j.micpath.2018.07.002}, pmid = {30057355}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/classification/*pharmacology ; Biofilms/*drug effects/growth & development ; *Drug Development ; Drug Discovery ; Drug Resistance, Bacterial/genetics/physiology ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/pathogenicity/physiology ; Microbial Sensitivity Tests ; Staphylococcal Infections/genetics/microbiology ; Staphylococcus aureus/*drug effects/genetics/pathogenicity/*physiology ; }, abstract = {The Staphylococcus aureus biofilm-associated burden is challenging to the field of medicine to eradicate or avoid it. Even though a number of S. aureus biofilm mechanisms understood and established the possible ways of biofilm formation but, still need to know more and require a development of new therapeutic strategies. In this viewpoint, we discuss the underlining biofilm mechanism, its existing systems as active therapeutic agents and as vehicles to transport drugs to the site of infection. The step-back in drug development is due to the emergence of antibiotic-resistant S. aureus. The understanding of bacteria/biofilms is an aspect that we likewise summarize for possible drug development for future as medicine against resistant S. aureus was viewed.}, } @article {pmid30054101, year = {2018}, author = {Chen, L and Li, X and Zhou, X and Zeng, J and Ren, Z and Lei, L and Kang, D and Zhang, K and Zou, J and Li, Y}, title = {Inhibition of Enterococcus faecalis Growth and Biofilm Formation by Molecule Targeting Cyclic di-AMP Synthetase Activity.}, journal = {Journal of endodontics}, volume = {44}, number = {9}, pages = {1381-1388.e2}, doi = {10.1016/j.joen.2018.05.008}, pmid = {30054101}, issn = {1878-3554}, mesh = {Adenylyl Cyclase Inhibitors/*pharmacology ; Biofilms/*drug effects ; Dinucleoside Phosphates/*physiology ; Enterococcus faecalis/*drug effects/enzymology/physiology ; }, abstract = {INTRODUCTION: Enterococcus faecalis is correlated with oral diseases including recurrent root canal treatment failure because of its biofilm formation ability and various virulence factors. Cyclic di-AMP (c-di-AMP) is an omnipresent second messenger involved in many crucial cellular physiological processes, including biofilm formation. ST056083 is a small molecule working as an inhibitor of the c-di-AMP synthetase DNA integrity scanning protein (DisA) in vitro. In this study, the impact of ST056083 on E. faecalis DisA activity, bacterial growth, and biofilm formation was tested.

METHODS: The binding affinity between the protein and ligand was evaluated using the Amber score, and the binding mode was analyzed and visualized using UCSF Chimera (Resource for Biocomputing, Visualization, and Informatics, University of California, San Francisco, San Francisco, CA). The effect of ST056083 on E. faecalis DisA was evaluated using the coralyne assay. The effect of ST056083 on E. faecalis biofilm formation was determined by the biofilm quantification assay, scanning electron microscopic examination, and 3-dimensional confocal laser scanning microscopic assay. The effect of ST056083 on E. faecalis exopolysaccharide synthesis was measured by the anthrone-sulfuric method.

RESULTS: We expressed and purified E. faecalis DisA in vitro and confirmed the inhibitory effect of ST056083 on its biological activity. In addition, we showed the inhibitory effect of ST056083 on E. faecalis growth, biofilm formation, and exopolysaccharide synthesis.

CONCLUSIONS: Our findings enhance the understanding of the physiological role of c-di-AMP in E. faecalis and represent a preliminary study on the ST056083 inhibitory effect and mechanism.}, } @article {pmid30053750, year = {2018}, author = {Ranieri, MR and Whitchurch, CB and Burrows, LL}, title = {Mechanisms of biofilm stimulation by subinhibitory concentrations of antimicrobials.}, journal = {Current opinion in microbiology}, volume = {45}, number = {}, pages = {164-169}, doi = {10.1016/j.mib.2018.07.006}, pmid = {30053750}, issn = {1879-0364}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/genetics ; Bacterial Infections/drug therapy/microbiology ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Biofilms are a typical mode of growth for most microorganisms and provide them with a variety of survival benefits. Biofilms can pose medical and industrial challenges due to their increased tolerance of antimicrobials and disinfectants. Exposure of bacteria to subinhibitory concentrations of those compounds can further exacerbate the problem, as they provoke physiological changes that lead to increased biofilm production and potential therapeutic failure. The protected niche of a biofilm provides conditions that promote selection for persisters and resistant mutants. In this review we discuss our current understanding of the mechanisms underlying biofilm stimulation in response to subinhibitory antimicrobials, and how we might exploit this 'anti-antibiotic' phenotype to treat biofilm-related infections and discover new compounds.}, } @article {pmid30052962, year = {2017}, author = {Trøstrup, H and Lerche, CJ and Christophersen, LJ and Thomsen, K and Jensen, PØ and Hougen, HP and Høiby, N and Moser, C}, title = {Erratum: Chronic Pseudomonas aeruginosa biofilm infection impairs murine S100A8/A9 and neutrophil effector cytokines-implications for delayed wound closure?.}, journal = {Pathogens and disease}, volume = {75}, number = {8}, pages = {}, doi = {10.1093/femspd/ftx110}, pmid = {30052962}, issn = {2049-632X}, } @article {pmid30052909, year = {2019}, author = {Kakade, P and Mahadik, K and Balaji, KN and Sanyal, K and Nagaraja, V}, title = {Two negative regulators of biofilm development exhibit functional divergence in conferring virulence potential to Candida albicans.}, journal = {FEMS yeast research}, volume = {19}, number = {2}, pages = {}, doi = {10.1093/femsyr/foy078}, pmid = {30052909}, issn = {1567-1364}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*genetics/*growth & development/pathogenicity ; Candidiasis/microbiology/*pathology ; Disease Models, Animal ; Gene Deletion ; *Gene Expression Regulation, Fungal ; Inflammation/pathology ; Mice, Inbred BALB C ; Transcription Factors/genetics/*metabolism ; Virulence ; }, abstract = {Candida albicans, a human pathogen, carries an expanded family of Zn(II)2Cys6 transcription factors. A CTG clade-specific protein Zcf32 and its closely related protein Upc2, a well-conserved transcription factor across the various fungal species, belong to this family of proteins. Unlike Upc2, Zcf32 is poorly studied in C. albicans. Here, we examined roles played by these two related transcription factors in biofilm development and virulence of C. albicans. Our data show that the null mutants of each of Zcf32 or Upc2 form better biofilms than the wild-type suggesting that both of them negatively regulate the biofilm development. While acting as negative regulators of biofilm formation, these two transcription factors target a different set of biofilm genes. A mouse model of candidiasis reveals that zcf32/zcf32 was hypervirulent, while upc2/upc2 shows compromised virulence compared to the wild-type. Notably, the absence of Zcf32 enhances detrimental inflammation brought about by TNFα, IFNβ and IFNγ. upc2/upc2 failed to generate a similar feedback, instead demonstrated an elevated anti-inflammatory (IL4 and IL10) host response. Taking together, we show how a recently evolved transcription factor Zcf32 retained functional resemblance with a more ubiquitous member Upc2 but also functionally diverged from the latter in the regulation of biofilm development and virulence of the pathogen.}, } @article {pmid30052177, year = {2018}, author = {Nandu, TG and Subramenium, GA and Shiburaj, S and Viszwapriya, D and Iyer, PM and Balamurugan, K and Rameshkumar, KB and Karutha Pandian, S}, title = {Fukugiside, a biflavonoid from Garcinia travancorica inhibits biofilm formation of Streptococcus pyogenes and its associated virulence factors.}, journal = {Journal of medical microbiology}, volume = {67}, number = {9}, pages = {1391-1401}, doi = {10.1099/jmm.0.000799}, pmid = {30052177}, issn = {1473-5644}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Biflavonoids/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans ; Garcinia/*chemistry ; Humans ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Streptococcal Infections/*microbiology ; Streptococcus pyogenes/*drug effects/genetics/physiology ; Virulence Factors/*genetics/metabolism ; }, abstract = {PURPOSE: Streptococcus pyogenes, a notorious human pathogen thatis responsible for various invasive and non-invasive diseases, possesses multiple virulence armaments, including biofilm formation. The current study demonstrates the anti-biofilm and anti-virulence potential of fukugiside, a biflavonoid isolated from Garciniatravancorica, against S. pyogenes.

METHODOLOGY: The anti-biofilm activity of fukugiside was assessed and established using microdilution and microscopic analysis. Biochemical assays were performed to assess the effects of fukugiside on important virulence factors, which were further validated using quantitative real-time PCR and in vivo analysis in Caenorhabditis elegans.

RESULTS: Fukugiside exhibited concentration-dependent biofilm inhibition (79 to 96 %) against multiple M serotypes of S. pyogenes (M1, M56, M65, M74, M100 and st38) with a minimum biofilm inhibitory concentration of 80 µg ml[-1]. Electron microscopy and biochemical assay revealed a significant reduction in extracellular polymeric substance production. The results for the microbial adhesion to hydrocarbon assay, extracellular protease quantification and differential regulation of the dltA, speB, srv and ropB genes suggested that fukugiside probably inhibits biofilm formation by lowering cell surface hydrophobicity and destabilizing the biofilm matrix. The enhanced susceptibility to phagocytosis evidenced in the blood survival assay goes in unison with the downregulation of mga. The downregulation of important virulence factor-encoding genes such as hasA, slo and col370 suggested impaired virulence. In vivo analysis in C. elegans evinced the non-toxic nature of fukugiside and its anti-virulence potential against S. pyogenes.

CONCLUSION: Fukugiside exhibits potent anti-biofilm and anti-virulence activity against different M serotypes of S. pyogenes. It is also non-toxic, which augurs well for its clinical application.}, } @article {pmid30050506, year = {2018}, author = {Balasubramanian, S and Skaf, J and Holzgrabe, U and Bharti, R and Förstner, KU and Ziebuhr, W and Humeida, UH and Abdelmohsen, UR and Oelschlaeger, TA}, title = {A New Bioactive Compound From the Marine Sponge-Derived Streptomyces sp. SBT348 Inhibits Staphylococcal Growth and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1473}, pmid = {30050506}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 μg/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 μg/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs.}, } @article {pmid30049528, year = {2018}, author = {Fang, Y and Deng, C and Chen, J and Lü, J and Chen, S and Zhou, S}, title = {Accelerating the start-up of the cathodic biofilm by adding acyl-homoserine lactone signaling molecules.}, journal = {Bioresource technology}, volume = {266}, number = {}, pages = {548-554}, doi = {10.1016/j.biortech.2018.07.095}, pmid = {30049528}, issn = {1873-2976}, mesh = {*Acyl-Butyrolactones ; *Biofilms ; Electrodes ; Geobacter ; Quorum Sensing ; }, abstract = {Electroactive biofilms (EABs) are essential for bioelectrochemical systems, however, the formation of cathodic EABs is more time-consuming than anodic EABs. This study aims to evaluate whether acyl-homoserine lactones (AHLs) could facilitate the start-up of cathodic Geobacter soli EABs. With AHL addition, the biomass, cell viability, and extracellular polymeric substance (EPS) abundance of cathode-associated G. soli EABs were increased. Likewise, redox activities of EPS and outermost proteins in the cathodic EABs were enhanced in the presence of AHLs, which consequently led to better start-up performance of biofilms. Compared to the control without AHLs, start-up lag periods were reduced by approximately 50%, electron uptakes were enhanced by 1.3-2.0 times, and denitrification rates were more than doubled with AHL addition in the start-up cycle, which were comparable to those of mature G. soli cathodic EABs. These findings open up an opportunity for accelerating the start-up of cathodic biofilms via AHLs.}, } @article {pmid30049271, year = {2018}, author = {Akens, MK and Chien, C and Katchky, RN and Kreder, HJ and Finkelstein, J and Whyne, CM}, title = {The impact of thermal cycling on Staphylococcus aureus biofilm growth on stainless steel and titanium orthopaedic plates.}, journal = {BMC musculoskeletal disorders}, volume = {19}, number = {1}, pages = {260}, pmid = {30049271}, issn = {1471-2474}, support = {23350//Ontario Centres of Excellence/ ; }, mesh = {Biofilms/*growth & development ; Bone Plates/*microbiology ; Hot Temperature/*therapeutic use ; Humans ; Orthopedic Procedures/instrumentation ; Proof of Concept Study ; Prosthesis-Related Infections/microbiology/therapy ; Random Allocation ; Single-Blind Method ; *Stainless Steel ; Staphylococcus aureus/*physiology ; *Titanium ; }, abstract = {BACKGROUND: Orthopaedic implant infections are difficult to eradicate because bacteria adhering to implant surfaces inhibit the ability of the immune system and antibiotics to combat these infections. Thermal cycling is a temperature modulation process that improves performance and longevity of materials through molecular structural reorientation, thereby increasing surface uniformity. Thermal cycling may change material surface properties that reduce the ability for bacteria to adhere to the surface of orthopaedic implants. This study aims to determine whether thermal cycling of orthopaedic implants can reduce bacterial growth.

METHODS: In a randomized, blinded in-vitro study, titanium and stainless steel plates treated with thermal cycling were compared to controls. Twenty-seven treated and twenty-seven untreated plates were covered with 10 ml tryptic soy broth containing ~ 10[5] colony forming units (CFU)/ml of bioluminescent Staphylococcus aureus (S. aureus)Xen29 and incubated at 37 °C for 14d. Quantity and viability of bacteria were characterized using bioluminescence imaging, live/dead staining and determination of CFUs.

RESULTS: Significantly fewer CFUs grow on treated stainless steel plates compared to controls (p = 0.0088). Similar findings were seen in titanium plates (p = 0.0048) following removal of an outlier. No differences were evident in live/dead staining using confocal microscopy, or in metabolic activity determined using bioluminescence imaging (stainless steel plates: p = 0.70; titanium plates: p = 0.26).

CONCLUSION: This study shows a reduction in CFUs formation on thermal cycled plates in-vitro. Further in-vivo studies are necessary to investigate the influence of thermal cycling on bacterial adhesion during bone healing. Thermal cycling has demonstrated improved wear and strength, with reductions in fatigue and load to failure. The added ability to reduce bacterial adhesions demonstrates another potential benefit of thermal cycling in orthopaedics, representing an opportunity to reduce complications following fracture fixation or arthroplasty.}, } @article {pmid30048488, year = {2018}, author = {Hussain, MS and Kwon, M and Oh, DH}, title = {Impact of manganese and heme on biofilm formation of Bacillus cereus food isolates.}, journal = {PloS one}, volume = {13}, number = {7}, pages = {e0200958}, pmid = {30048488}, issn = {1932-6203}, mesh = {Bacillus cereus/cytology/*drug effects/genetics/*physiology ; Bacterial Proteins/genetics ; Benzalkonium Compounds/pharmacology ; Biofilms/*drug effects/*growth & development ; *Food Microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Heme/*pharmacology ; Manganese/*pharmacology ; Phenotype ; }, abstract = {The objective of this study was to determine the impact of manganese (Mn2+) and heme on the biofilm formation characteristics of six B. cereus food isolates and two reference strains (ATCC 10987 and ATCC 14579). The data obtained from the crystal violet assay revealed that addition of a combination of Mn2+ and heme to BHI growth medium induced B. cereus biofilm formation. However, the induction of biofilm formation was strictly strain-dependent. In all of the induced strains, the impact of Mn2+ was greater than that of heme. The impact of these two molecules on the phenotypic characteristics related to biofilm formation, such as cell density, sporulation and swarming ability, was determined in a selected food isolate (GIHE 72-5). Addition of Mn2+ and heme to BHI significantly (p < 0.05) increased the number of cells, which was correlated with the results of crystal violet assays as well as scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses. In addition, induced biofilms showed higher numbers of spores and greater resistance to benzalkonium chloride. The swarming ability of B. cereus planktonic cells was increased in the presence of Mn2+ and heme in BHI. The expression levels of a number of selected genes, which are involved in mobility and extracellular polymeric substances (EPS) formation in B. cereus, were positively correlated with biofilm formation in the presence of Mn2+ and heme in BHI. These results further confirming the role of these molecules in swarming mobility and making matrix components related to B. cereus biofilm formation. These data indicate that signaling molecules present in the food environment might substantially trigger B. cereus biofilm formation, which could pose a threat to the food industry.}, } @article {pmid30048376, year = {2018}, author = {Kim, YS}, title = {Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.}, journal = {Plastic and reconstructive surgery}, volume = {142}, number = {4}, pages = {588e-589e}, doi = {10.1097/PRS.0000000000004744}, pmid = {30048376}, issn = {1529-4242}, mesh = {Bacteria ; Biofilms ; *Breast Implantation ; *Breast Implants ; }, } @article {pmid30048200, year = {2018}, author = {Kenaley, KM and Blackson, T and Boylan, L and Ciarlo, J and Antunes, M and Shaffer, TH and Locke, R}, title = {Impact of endotracheal tube biofilm and respiratory secretions on airway resistance and mechanics of breathing in a neonatal lung model.}, journal = {Journal of applied physiology (Bethesda, Md. : 1985)}, volume = {125}, number = {4}, pages = {1227-1231}, doi = {10.1152/japplphysiol.00083.2018}, pmid = {30048200}, issn = {1522-1601}, abstract = {Endotracheal tube (ETT) obstruction from biofilm formation is a theoretical risk for intubated preterm neonates. The objective of this study is to determine the impact of ETT biofilm on ETT resistance and minute ventilation in a neonatal respiratory model. Postextubation 2.5- and 3.0-mm ETTs from ventilated preterm infants were matched with unused control ETTs. The pressure gradient across the ETT was measured at set flow rates and converted to airway resistance. Spontaneous breathing tests (SBTs) were performed using a virtual patient model and were considered "passed" if minute ventilation of patient ETTs was greater than 60% of control ETTs. Twenty-four 2.5-mm ETTs and sixteen 3.0-mm ETTs were analyzed. In both patient and control ETTs, as flow rate increases, the pressure gradient across the ETT also increases in a linear fashion. Resistance to flow in patient ETTs was statistically different from matched control ETTs (P < 0.001), and patient ETTs had 19.9 cmH2O·l[-1]·sec[-1] greater resistance than control ETTs. SBTs were performed in 27 of 40 ETTs. Twenty-six ETTs "passed" an SBT. In one obstructed 3.0-mm ETT, SBT measurements were unobtainable. The clinical impact of ETT biofilm as measured by a SBT appears to be minimal for the majority of patients in our study group. In 1 out of 27 ETTs, the presence of a biofilm significantly altered resistance to airflow and resulted in a failed SBT. Gas flow rate and ETT size had a greater impact on resistance to airflow and minute ventilation than ETT biofilm in this study sample.NEW & NOTEWORTHY This is the first study to our knowledge to characterize the impact of endotracheal tube (ETT) biofilm and respiratory secretions on resistance to airflow in a neonatal ETT using a simulation neonatal lung model. Results show that the clinical impact of ETT biofilm is minimal for the majority of patients in our study group, and ETT obstruction from biofilm is an uncommon cause of respiratory decompensation in a preterm neonate.}, } @article {pmid30048150, year = {2019}, author = {Stevens, AH and Childers, D and Fox-Powell, M and Nicholson, N and Jhoti, E and Cockell, CS}, title = {Growth, Viability, and Death of Planktonic and Biofilm Sphingomonas desiccabilis in Simulated Martian Brines.}, journal = {Astrobiology}, volume = {19}, number = {1}, pages = {87-98}, pmid = {30048150}, issn = {1557-8070}, mesh = {Biofilms/*growth & development ; Biomass ; Desiccation ; *Mars ; Plankton ; Sphingomonas/*growth & development ; }, abstract = {Aqueous solutions on Mars are theorized to contain very different ion compositions than those on Earth. To determine the effect of such solutions on typical environmental micro-organisms, which could be released from robotic spacecraft or human exploration activity, we investigated the resistance of Sphingomonas desiccabilis to brines that simulate the composition of martian aqueous environments. S. desiccabilis is a desiccation-resistant, biofilm-forming microbe found in desert crusts. The viability of cells in both planktonic and biofilm forms was measured after exposure to simulated martian brines. Planktonic cells showed a loss of viability over the course of several hours in almost all of the seven brines tested. Biofilms conferred greater resistance to all the brines, including those with low water activity and pH, but even cells in biofilms showed a complete loss of viability in <6 h in the harsher brines and in <2 days in the less harsh brines. One brine, however, allowed the microbes to maintain viability over several days, despite having a water activity and pH lower and ionic strength higher than brines that reduced viability over the same timescales, suggesting important ion-specific effects. These data show that biofilm-forming cells have a greater capacity to resist martian aqueous extremes, but that evaporative or deliquescent brines are likely to be destructive to many organisms over relatively short timescales, with implications for the habitability of Mars and for micro-organisms dispersed by robotic or human explorers.}, } @article {pmid30047246, year = {2018}, author = {Zhao, T and Zhang, Y and Wu, H and Wang, D and Chen, Y and Zhu, MJ and Ma, LZ}, title = {Extracellular aminopeptidase modulates biofilm development of Pseudomonas aeruginosa by affecting matrix exopolysaccharide and bacterial cell death.}, journal = {Environmental microbiology reports}, volume = {10}, number = {5}, pages = {583-593}, doi = {10.1111/1758-2229.12682}, pmid = {30047246}, issn = {1758-2229}, support = {/CA/NCI NIH HHS/United States ; }, mesh = {Aminopeptidases/genetics/*metabolism ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/*enzymology/metabolism ; Gene Deletion ; Microbial Viability ; Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas aeruginosa/enzymology/metabolism/*physiology ; }, abstract = {Biofilm bacteria are embedded within a self-secreted extracellular matrix that contains a considerable amount of proteins including many extracellular enzymes. However, little is known about the roles of such enzymes in biofilm development. Here, we studied Pseudomonas aeruginosa aminopeptidase (PaAP, encoded by PA2939 that we named the gene as paaP in this study), a quorum-sensing-regulated enzyme and one of the most abundant extracellular proteins in the biofilm matrix of this opportunistic pathogen and environmental bacterium. We found that deletion of paaP in P. aeruginosa increased initial attachment and biofilm formation at early stages of biofilm development. After 24 h growth, loss of PaAP resulted in substantial cell death and biofilm disruption. Bacterial cell death was independent of biofilm matrix polysaccharide Psl, while biofilm disruption was due to the degradation of Psl matrix by dead-bacteria-released glycosyl hydrolase PslG, thereby leading to biofilm dispersion. PaAP functioned extracellularly and aminopeptidase catalytic activity was essential for its effect on biofilm development. Our data reveal an important role of extracellular aminopeptidase in biofilm development, suggesting PaAP as a therapeutic target for preventing P. aeruginosa infection and combating biofilm-related complications.}, } @article {pmid30046559, year = {2018}, author = {Barilli, E and Bacci, C and StellaVilla, Z and Merialdi, G and D'Incau, M and Brindani, F and Vismarra, A}, title = {Antimicrobial resistance, biofilm synthesis and virulence genes in Salmonella isolated from pigs bred on intensive farms.}, journal = {Italian journal of food safety}, volume = {7}, number = {2}, pages = {7223}, pmid = {30046559}, issn = {2239-7132}, abstract = {Salmonella is the second cause of food-borne infection in humans in the USA and Europe. Pigs represent the second most important reservoir for the pathogen and the consumption of pork meat is a major risk factor for human salmonellosis. Here, we evaluated the virulence patterns of eleven Salmonella isolated from pigs (carcasses and faces) bred in intensive farms in the north of Italy. The two serotypes identified were S. Typhimurium and its monophasic variant 1,4,5,12:i:-. None of the isolates was an ESBL producer, as confirmed also by PCR. However, the presence of a multi-drug resistant pattern was evident, with all the isolates being resistant to at least to five antimicrobial agents belonging to various classes. Moreover, six out of eleven isolates showed important resistance profiles, such as resistance against colistin and ciprofloxacin, with nine to twelve recorded resistances. The isolates were negative for the biofilm synthesis test, while four different virulotypes were characterized. All the isolates showed the presence of invA, hilA, stn, ssrA, sipC. One sample also harbored ssaR and spvC genes. One strain was positive for all the virulence genes tested and was resistant to 12 antimicrobial agents. The present study contributes new data to the surveillance program for antibiotic resistance. Furthermore, the presence of eleven highly virulent isolates poses concern for human health in relation to their diffusion in the environment.}, } @article {pmid30043322, year = {2019}, author = {Jaśkiewicz, M and Neubauer, D and Kazor, K and Bartoszewska, S and Kamysz, W}, title = {Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii.}, journal = {Probiotics and antimicrobial proteins}, volume = {11}, number = {1}, pages = {317-324}, pmid = {30043322}, issn = {1867-1314}, support = {ST-02-0087/07/508//Medical University of Gdansk statutory grant/International ; 01-0305/08/508//Polish Ministry of Science and Higher Education Grant for Young Investigators/International ; }, mesh = {Acinetobacter baumannii/*drug effects/genetics/physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Line, Tumor ; Cell Survival/drug effects ; Humans ; Microbial Sensitivity Tests ; Peptides/*pharmacology ; Plankton/*drug effects/genetics/physiology ; }, abstract = {Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.}, } @article {pmid30043188, year = {2018}, author = {Han, X and Zhang, LJ and Wu, HY and Wu, YF and Zhao, SN}, title = {Investigation of microorganisms involved in kefir biofilm formation.}, journal = {Antonie van Leeuwenhoek}, volume = {111}, number = {12}, pages = {2361-2370}, doi = {10.1007/s10482-018-1125-6}, pmid = {30043188}, issn = {1572-9699}, support = {31271906/C200204//National Natural Science Foundation of China/ ; }, mesh = {Acetobacter/*chemistry/genetics/isolation & purification/metabolism ; Bacterial Adhesion ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; DNA, Fungal/genetics ; Fermentation ; Food Microbiology ; Hydrophobic and Hydrophilic Interactions ; Kefir/*microbiology ; Kluyveromyces/*chemistry/genetics/isolation & purification/metabolism ; Lactobacillus/*chemistry/genetics/isolation & purification/metabolism ; Lactococcus lactis/*chemistry/genetics/isolation & purification/metabolism ; Leuconostoc/*chemistry/genetics/isolation & purification/metabolism ; Microbial Consortia/genetics ; Static Electricity ; }, abstract = {Kefir is a natural fermentation agent composed of various microorganisms. To address the mechanism of kefir grain formation, we investigated the microbial role in forming kefir biofilms. The results showed that a biofilm could be formed in kefir-fermented milk and the biofilm forming ability reached the maximum at 13 days. The strains Kluyveromyces marxianus, Lactococcus lactis, Leuconostoc mesenteroides, Lactobacillus kefiri, Lactobacillus sunkii and Acetobacter orientalis were isolated from kefir biofilms by the streak-plate method. These microorganisms were analysed with respect to biofilm forming properties, including their surface characterisation (hydrophobicity and zeta potentials) and the microbial aggregation. The results indicated that Klu. marxianus possessed the strongest biofilm forming properties with the strongest hydrophobicity, lowest zeta potential and greatest auto-aggregation ability. When Klu. marxianus and Ac. orientalis were co-cultured with kefir LAB strains respectively, it was found that mixing Klu. marxianus with Lb. sunkii produced the highest co-aggregation ability. These results elucidated the mechanism of kefir biofilm formation and the microorganisms involved.}, } @article {pmid30042929, year = {2018}, author = {Romo, JA and Pierce, CG and Esqueda, M and Hung, CY and Saville, SP and Lopez-Ribot, JL}, title = {In Vitro Characterization of a Biaryl Amide Anti-virulence Compound Targeting Candida albicans Filamentation and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {227}, pmid = {30042929}, issn = {2235-2988}, support = {R01 AI063256/AI/NIAID NIH HHS/United States ; R01 AI119554/AI/NIAID NIH HHS/United States ; R21 AI149015/AI/NIAID NIH HHS/United States ; R25 GM060655/GM/NIGMS NIH HHS/United States ; }, mesh = {Amides/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/growth & development/isolation & purification/*pathogenicity ; Candidiasis/microbiology ; Drug Synergism ; Flow Cytometry ; Humans ; Hyphae/drug effects/growth & development ; Microbial Viability/drug effects ; Virulence/drug effects ; }, abstract = {We have previously identified a small molecule compound, N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (9029936), that exerts potent inhibitory activity against filamentation and biofilm formation by the Candida albicans SC5314 strain and represents a lead candidate for the development of anti-virulence approaches against C. albicans infections. Here we present data from a series of experiments to further characterize its in vitro activity and drug-like characteristics. We demonstrate the activity of this compound against a panel of C. albicans clinical isolates, including several displaying resistance to current antifungals; as well as against a set of C. albicans gain of function strains in key transcriptional regulators of antifungal drug resistance. The compound also inhibits filamentation and biofilm formation in the closely related species C. dubliniensis, but not C. glabrata or C. tropicalis. Combinatorial studies reveal the potential of compound 9029936 to be used together with currently available conventional antifungals. Results of serial passage experiments indicate that repeated exposure to this compound does not elicit resistance. Viability staining of C. albicans in the presence of high concentrations of compound 9029936 confirms that the compound is not toxic to fungal cells, and cytological staining using image flow cytometry analysis reveals that treatment with the lead compound affects hyphal length, with additional effects on cell wall and integrity of the membrane system. In vitro pharmacological profiling provides further evidence that the lead compound displays a safe profile, underscoring its excellent "drug-like" characteristics. Altogether these results confirm the potential of this compound to be further developed as a true anti-virulence agent for the treatment of C. albicans infections, including those refractory to treatment with conventional antifungal agents.}, } @article {pmid30042743, year = {2018}, author = {Zheng, Y and Li, Y and Long, H and Zhao, X and Jia, K and Li, J and Wang, L and Wang, R and Lu, X and Zhang, D}, title = {bifA Regulates Biofilm Development of Pseudomonas putida MnB1 as a Primary Response to H2O2 and Mn[2].}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1490}, pmid = {30042743}, issn = {1664-302X}, abstract = {Pseudomonas putida (P. putida) MnB1 is a widely used model strain in environment science and technology for determining microbial manganese oxidation. Numerous studies have demonstrated that the growth and metabolism of P. putida MnB1 are influenced by various environmental factors. In this study, we investigated the effects of hydrogen peroxide (H2O2) and manganese (Mn[2+]) on proliferation, Mn[2+] acquisition, anti-oxidative system, and biofilm formation of P. putida MnB1. The related orthologs of 4 genes, mco, mntABC, sod, and bifA, were amplified from P. putida GB1 and their involvement were assayed, respectively. We found that P. putida MnB1 degraded H2O2, and quickly recovered for proliferation, but its intracellular oxidative stress state was maintained, with rapid biofilm formation after H2O2 depletion. The data from mco, mntABC, sod and bifA expression levels by qRT-PCR, elucidated a sensitivity toward bifA-mediated biofilm formation, in contrary to intracellular anti-oxidative system under H2O2 exposure. Meanwhile, Mn[2+] ion supply inhibited biofilm formation of P. putida MnB1. The expression pattern of these genes showed that Mn[2+] ion supply likely functioned to modulate biofilm formation rather than only acting as nutrient substrate for P. putida MnB1. Furthermore, blockade of BifA activity by GTP increased the formation and development of biofilms during H2O2 exposure, while converse response to Mn[2+] ion supply was evident. These distinct cellular responses to H2O2 and Mn[2+] provide insights on the common mechanism by which environmental microorganisms may be protected from exogenous factors. We postulate that BifA-mediated biofilm formation but not intracellular anti-oxidative system may be a primary protective strategy adopted by P. putida MnB1. These findings will highlight the understanding of microbial adaptation mechanisms to distinct environmental stresses.}, } @article {pmid30042739, year = {2018}, author = {Khandekar, S and Liebens, V and Fauvart, M and Tulkens, PM and Michiels, J and Van Bambeke, F}, title = {The Putative De-N-acetylase DnpA Contributes to Intracellular and Biofilm-Associated Persistence of Pseudomonas aeruginosa Exposed to Fluoroquinolones.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1455}, pmid = {30042739}, issn = {1664-302X}, abstract = {Persisters are the fraction of antibiotic-exposed bacteria transiently refractory to killing and are recognized as a cause of antibiotic treatment failure. The putative de-N-acetylase DnpA increases persister levels in Pseudomonas aeruginosa upon exposure to fluoroquinolones in broth. In this study the wild-type PAO1 and its dnpA insertion mutant (dnpA::Tn) were used in parallel and compared for their capacity to generate persisters in broth (surviving fraction after exposure to high antibiotic concentrations) and their susceptibility to antibiotics in models of intracellular infection of THP-1 monocytes and of biofilms grown in microtiter plates. Multiplication in monocytes was evaluated by fluorescence dilution of GFP (expressed under the control of an inducible promoter) using flow cytometry. Gene expression was measured by quantitative RT-PCR. When exposed to fluoroquinolones (ciprofloxacin or levofloxacin) but not to meropenem or amikacin, the dnpA::Tn mutant showed a 3- to 10-fold lower persister fraction in broth. In infected monocytes, fluoroquinolones (but not the other antibiotics) were more effective (difference in Emax: 1.5 log cfu) against the dnpA::Tn mutant than against the wild-type PAO1. Dividing intracellular bacteria were more frequently seen (1.5 to 1.9-fold) with the fluoroquinolone-exposed dnpA::Tn mutant than with its parental strain. Fluoroquinolones (but not the other antibiotics) were also 3-fold more potent to prevent biofilm formation by the dnpA::Tn mutant than by PAO1 as well as to act upon biofilms (1-3 days of maturity) formed by the mutant than by the parental strain. Fluoroquinolones induced the expression of gyrA (4.5-7 fold) and mexX (3.6-5.4 fold) in the parental strain but to a lower extent (3-4-fold for gyrA and 1.8-2.8-fold for mexX, respectively) in the dnpA::Tn mutant. Thus, our data show that a dnpA insertion mutant of P. aeruginosa is more receptive to fluoroquinolone antibacterial effects than its parental strain in infected monocytes or in biofilms. The mechanism of this higher responsiveness could involve a reduced overexpression of the fluoroquinolone target.}, } @article {pmid30042679, year = {2018}, author = {Ding, W and Zhou, Y and Qu, Q and Cui, W and God'spower, BO and Liu, Y and Chen, X and Chen, M and Yang, Y and Li, Y}, title = {Azithromycin Inhibits Biofilm Formation by Staphylococcus xylosus and Affects Histidine Biosynthesis Pathway.}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {740}, pmid = {30042679}, issn = {1663-9812}, abstract = {Staphylococcus xylosus, a coagulase-negative, non-pathogenic bacterium, responsible for opportunistic infections in humans and bovine mastitis, has the ability to form biofilms, which are responsible for persistent infections and antibiotic resistance. In our study, azithromycin significantly inhibited biofilm formation by altering protein expression. Of the 1764 proteins measured by the isobaric Tag for Relative and Absolute Quantification (iTRAQ) technique, only 148 proteins showed significantly different expression between the azithromycin-treated and untreated cells. Most ribosomal proteins were markedly up-regulated, and the expression of the proteins involved in histidine biosynthesis, which, in turn, influence biofilm formation, was down-regulated, particularly imidazole glycerophosphate dehydratase (IGPD). Previously, we had observed that IGPD plays an important role in biofilm formation by S. xylosus. Therefore, hisB expression was studied by real-time PCR, and the interactions between azithromycin and IGPD were predicted by molecular docking analysis. hisB was found to be significantly down-regulated, and six bond interactions were observed between azithromycin and IGPD. Many active atoms of azithromycin did not interact with the biologically active site of IGPD. Surface plasmon resonance analysis used to further study the relationship between IGPD and azithromycin showed minimum interaction between them. Histidine content in the azithromycin-treated and untreated groups was determined. We noted a slight difference, which was not consistent with the expression of the proteins involved in histidine biosynthesis. Therefore, histidine degradation into glutamate was also studied, and we found that all proteins were down-regulated. This could be the reason why histidine content showed little change between the treated and untreated groups. In summary, we found that azithromycin is a potential inhibitor of S. xylosus biofilm formation, and the underlying mechanism was preliminarily elucidated in this study.}, } @article {pmid30042337, year = {2018}, author = {Dasagrandhi, C and Park, S and Jung, WK and Kim, YM}, title = {Antibacterial and Biofilm Modulating Potential of Ferulic Acid-Grafted Chitosan against Human Pathogenic Bacteria.}, journal = {International journal of molecular sciences}, volume = {19}, number = {8}, pages = {}, pmid = {30042337}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Membrane Permeability/drug effects ; Cell Movement/drug effects ; Cell Survival/drug effects ; Chitosan/*analogs & derivatives/*pharmacology ; Coumaric Acids/*chemistry ; Dose-Response Relationship, Drug ; Humans ; Listeria monocytogenes/*drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; }, abstract = {The emergence of more virulent forms of human pathogenic bacteria with multi-drug resistance is a serious global issue and requires alternative control strategies. The current study focused on investigating the antibacterial and antibiofilm potential of ferulic acid-grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The result showed that CFA at 64 µg/mL concentration exhibits bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log colony forming units/mL reduction) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to altered membrane integrity and permeability. CFA dose dependently inhibited biofilm formation (52[-]89% range), metabolic activity (30.8[-]75.1% range) and eradicated mature biofilms, and reduced viability (71[-]82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-minimum inhibitory concentration (MIC) concentrations of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will offer insights into a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.}, } @article {pmid30041533, year = {2018}, author = {Becirovic, A and Abdi-Dezfuli, JF and Hansen, MF and Lie, SA and Vasstrand, EN and Bolstad, AI}, title = {The effects of a probiotic milk drink on bacterial composition in the supra- and subgingival biofilm: a pilot study.}, journal = {Beneficial microbes}, volume = {9}, number = {6}, pages = {865-874}, doi = {10.3920/BM2018.0009}, pmid = {30041533}, issn = {1876-2891}, mesh = {Adult ; Animals ; Bacteria/*drug effects/*growth & development ; Biofilms/*drug effects/*growth & development ; Cross-Over Studies ; Dental Plaque/*prevention & control ; Female ; Gingiva/*microbiology ; Humans ; Male ; Milk ; Norway ; Pilot Projects ; Probiotics/*administration & dosage ; Treatment Outcome ; Young Adult ; }, abstract = {Probiotics can convert a dysbiotic bacterial environment into a healthy one. The aim of the present study was to assess the effect of daily intake of a probiotic milk drink on the composition of bacterial species in dental supra- and subgingival biofilms. Sixteen dental students were enrolled into this study with a crossover, within subject, design. The participants were asked to allow plaque accumulation by refraining from cleaning their molars during two separate periods, each lasting three weeks. Each period consisted of an initial professional dental cleaning procedure done at the university clinic, then a 3 week plaque accumulation period, followed by a return to the clinic for supra- and subgingival plaque sampling. The first period served as a control, and during the second plaque accumulation period the participants drank 200 ml probiotic milk beverage each day. The accumulated plaque removed at the end of the accumulation period was later tested against a panel of 20 oral bacterial species using the checkerboard method. Three weeks consumption of a probiotic beverage led to a significant reduction in 15 of 20 bacterial species present in supragingival plaque and a reduction in 4 of 20 bacterial species in subgingival plaque (all P<0.05). This study showed a favorable effect of probiotics on periodontopathic bacteria in dental biofilms. The potential influence of this kind of probiotic in prevention or treatment of periodontal inflammation deserves further study.}, } @article {pmid30041001, year = {2018}, author = {Zhang, X and Manukumar, HM and Rakesh, KP and Karthik, CS and Nagendra Prasad, HS and Swamy, SN and Mallu, P and Eissa Mohammed, YH and Qin, HL}, title = {Role of BP*C@AgNPs in Bap-dependent multicellular behavior of clinically important methicillin-resistant Staphylococcus aureus (MRSA) biofilm adherence: A key virulence study.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {275-284}, doi = {10.1016/j.micpath.2018.07.025}, pmid = {30041001}, issn = {1096-1208}, mesh = {Amino Acid Sequence ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Bacterial Adhesion/drug effects ; Benzodioxoles ; Binding Sites ; Biofilms/*drug effects ; Calcium/metabolism ; Chitosan ; Drug Combinations ; Endopeptidase K/pharmacology ; Heterocyclic Compounds, 2-Ring/chemistry/pharmacology ; Metal Nanoparticles/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Silver/*pharmacology ; Staphylococcal Infections/microbiology ; Virulence/drug effects ; }, abstract = {Bacterial adhesion is a threshold event in the formation of biofilms which leads to serious bacterial diseases. This shows that the underlining the problem is interesting and need to solve the problem of biofilm-related complications. To support this, in the present study, we first time initiated to understand the role of methicillin-resistant Staphylococcus aureus (MRSA) biofilm using previously developed benzodioxane midst piperazine decorated chitosan silver nanoparticles (BP*C@AgNPs). The BP*C@AgNPs studied for antimicrobial, anti-biofilm, biofilm adherence inhibition, the role of ions in biofilm, and an antibiotic cocktail in the treatment of biofilm was assessed. The results showed that, the significant biocidal role of BP*C@AgNPs in controlling the MRSA biofilm and interaction of biofilm protein to calcium ions were significantly decreased. This confirms that calcium ion involved in the biofilm formation and for the treatment of BP*C@AgNPs, cocktail of enzyme and antibiotic have the promising therapeutic value was observed. In future the locking of biofilm protein and its expression in presence of calcium ion was interesting, and greater application related to biofilm infection was warrantable.}, } @article {pmid30039322, year = {2018}, author = {Chakraborty, P and Daware, AV and Kumari, M and Chatterjee, A and Bhattacharyya, D and Mitra, G and Akhter, Y and Bhattacharjee, S and Tribedi, P}, title = {Free tryptophan residues inhibit quorum sensing of Pseudomonas aeruginosa: a potential approach to inhibit the development of microbial biofilm.}, journal = {Archives of microbiology}, volume = {200}, number = {10}, pages = {1419-1425}, doi = {10.1007/s00203-018-1557-4}, pmid = {30039322}, issn = {1432-072X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/chemistry/genetics/metabolism ; Biofilms/*drug effects ; Mice ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/genetics/metabolism/physiology ; Quorum Sensing/*drug effects/genetics ; RAW 264.7 Cells ; Tryptophan/*pharmacology ; }, abstract = {Microbial biofilm reveals a cluster of microbial population aggregated on a surface. Pseudomonas aeruginosa, a strong biofilm forming organism, often causes several human diseases. Microorganism-based diseases become more difficult to manage when the causative organism develops biofilm during the course of disease progression as the organism attains alarming drug resistance in biofilm form. Agents inhibiting microbial biofilm formation could be considered as a potential tool to weaken the extent of microbial pathogenesis. Tryptophan has already been reported as a promising agent against the biofilm development by P. aeruginosa. In the current study, we had focused on the underlying mechanism of microbial biofilm inhibition of P. aeruginosa under the influence of tryptophan. The expression level of the mRNA of the genes (lasR, lasB and lasI) associated with quorum sensing was compared between tryptophan treated and untreated cells under similar conditions using real time polymerase chain reaction (RT-PCR). The results showed that the tested concentrations of tryptophan considerably reduced the expression of those genes (lasR, lasB and lasI) that are required during the occurrence of quorum sensing in P. aeruginosa. Molecular docking also revealed that tryptophan can interact with the proteins responsible for the occurrence of quorum sensing in P. aeruginosa. The cytotoxicity assay was carried out wherein we observed that the tested concentration of tryptophan did not show any considerable cytotoxicity against the RAW 264.7 macrophage cell line. From this study, it may be concluded that the tryptophan-mediated inhibition of biofilm formation is associated with interference of quorum sensing in P. aeruginosa. Hence, tryptophan could be used as a potential agent against the microbial biofilm mediated pathogenesis.}, } @article {pmid30036851, year = {2018}, author = {Lu, B and Lu, F and Ran, L and Yu, K and Xiao, Y and Li, Z and Dai, F and Wu, D and Lan, G}, title = {Imidazole-molecule-capped chitosan-gold nanocomposites with enhanced antimicrobial activity for treating biofilm-related infections.}, journal = {Journal of colloid and interface science}, volume = {531}, number = {}, pages = {269-281}, doi = {10.1016/j.jcis.2018.07.058}, pmid = {30036851}, issn = {1095-7103}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Cell Line ; Chitosan/chemistry/*pharmacology ; Escherichia coli/*drug effects/physiology ; Escherichia coli Infections/drug therapy ; Gold/chemistry/*pharmacology ; Humans ; Imidazoles/chemistry/*pharmacology ; Mice ; Nanocomposites/chemistry ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Biofilms that are widely associated with persistent bacterial infections impose a heavy burden on patients primarily due to their formidable resistance to conventional antiseptic drugs and local immune defense. Here, we successfully synthesized functional gold nanocomposites (CS-Au@MMT) by reducing chloroauric acid in the presence of biocompatible chitosan polymers with cationic amine and the small molecule 2-mercapto-1-methylimidazole (MMT). The cationic amine allowed transport of the CS-Au@MMT to the negatively charged sites at the surface of bacterial cells though electrostatic adhesion, with synergistic effects from the gold nanoparticles and MMT then exerting a strong bactericidal effect to inhibit biofilm formation. For established mature biofilms, CS-Au@MMT was able to adhere to the biofilm surface to render nearby bacterial cells inactive, resulting in biofilm rupture. This allowed CS-Au@MMT to penetrate through the biofilm, leading to sustained damage and achieving biofilm elimination. Furthermore, the nanocomposites efficiently inhibited infections induced by mature biofilm in vivo. These findings indicated that the CS-Au@MMT nanocomposites provide ease of synthesis and fabrication, high bactericidal effect, and low toxicity; thus, they show potential as biofilm-disrupting agents for biomedical and industrial applications.}, } @article {pmid30036345, year = {2018}, author = {Wang, C and Luan, J and Xin, M}, title = {Capsular Biofilm Formation at the Interface of Textured Expanders and Human Acellular Dermal Matrix.}, journal = {Plastic and reconstructive surgery}, volume = {142}, number = {4}, pages = {587e}, doi = {10.1097/PRS.0000000000004781}, pmid = {30036345}, issn = {1529-4242}, mesh = {*Acellular Dermis ; Biofilms ; Breast Implants ; Humans ; *Microscopy, Electron, Scanning ; Tissue Expansion Devices ; }, } @article {pmid30036344, year = {2018}, author = {Danino, MA and Efanov, JI and Paek, L and Nelea, MI}, title = {Reply: Capsular Biofilm Formation at the Interface of Textured Implants and Acellular Dermal Matrix: A Comparative Scanning Electron Microscopy Study.}, journal = {Plastic and reconstructive surgery}, volume = {142}, number = {4}, pages = {587e-588e}, doi = {10.1097/PRS.0000000000004782}, pmid = {30036344}, issn = {1529-4242}, mesh = {*Acellular Dermis ; Biofilms ; Breast Implants ; Humans ; *Microscopy, Electron, Scanning ; Tissue Expansion Devices ; }, } @article {pmid30034907, year = {2018}, author = {Zhou, X and Meng, J and Yu, Z and Miao, L and Jin, C}, title = {The Alterations of Biofilm Formation and EPS Characteristics of a Diatom by a Sponge-Associated Bacterium Psychrobacter sp.}, journal = {Scientifica}, volume = {2018}, number = {}, pages = {1892520}, pmid = {30034907}, issn = {2090-908X}, abstract = {A sponge-associated bacterium, which was identified as Psychrobacter sp. in this study, was found with high activity against biofilm formation of benthic diatoms, including Amphora sp., Nitzschia closterium, Nitzschia frustulum, and Stauroneis sp. The activity against diatom biofilm formation by the tested strain was confirmed mostly in the culture supernatant and could be extracted using organic solvents. Treatment with its supernatant crude extract significantly reduced the cells of Stauroneis sp. forming biofilm and slightly increased the cells floating in the culture medium, which results in the ratio of biofilm cell/floating cell altering from 0.736 in control to 0.414 in treatment. Use of the supernatant crude extract led to increased production of extracellular polymeric substances (EPSs) by diatom Stauroneis sp. from 16.66 to 41.59 (g/g cell dry weight). The increase in EPS production was mainly contributed by soluble EPS (SL-EPS) and followed by the EPS that was tightly bound to biofilm cells (BF-TB-EPS). In addition, the supernatant crude extract caused significant changes in the monosaccharides composition of the EPS of Stauroneis sp. Specifically, glucuronic acid (Glc-A) and N-acetyl-D-glucosamine (Glc-NAc) in BF-TB-EPS were 55% fold decreased and 1219% fold increased, respectively. Based on our findings, we proposed that these changes in monosaccharides composition might lead to a decreased biofilm formation efficiency of diatom.}, } @article {pmid30034429, year = {2018}, author = {Saba, T and Sajid, M and Khan, AA and Zahra, R}, title = {Role of Intracellular Adhesion icaAD and agr genes in Biofilm Formation in Clinical S. aureus Isolates and Assessment of Two Phenotypic Methods.}, journal = {Pakistan journal of medical sciences}, volume = {34}, number = {3}, pages = {633-637}, pmid = {30034429}, issn = {1682-024X}, abstract = {OBJECTIVE: To determine the role of icaAD and agr genes in biofilm formation and evaluate the consistency of two phenotypic methods for biofilm measurement.

METHODS: A total of 81 clinical S. aureus strains were included and analyzed for biofilm formation by two methods. The microtitration plate method was optimized using computational fluid dynamics and compared with the Congo red assay. The genes for icaAD and agr were detected using PCR.

RESULTS: Of 81 isolates, biofilm production was detected in 43% isolates using Congo red method while microtiter plate assay showed biofilm production in 92% isolates. Both methods showed correlation in 30% isolates. PCR detection showed icaAD gene in 42 (52%) isolates. Out of 81 S. aureus isolates 65 strains (80%) contained agr while 16 (20%) strains were non-typeable.

CONCLUSIONS: In conclusion, biofilm production was observed for both agr positive and agr negative isolates. Furthermore, the presence of icaAD genes was not associated with all biofilm producing strains as some strains negative for icaAD genes displayed biofilm production.}, } @article {pmid30034372, year = {2018}, author = {Zhu, X and Liu, D and Singh, AK and Drolia, R and Bai, X and Tenguria, S and Bhunia, AK}, title = {Tunicamycin Mediated Inhibition of Wall Teichoic Acid Affects Staphylococcus aureus and Listeria monocytogenes Cell Morphology, Biofilm Formation and Virulence.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1352}, pmid = {30034372}, issn = {1664-302X}, abstract = {The emergence of bacterial resistance to therapeutic antibiotics limits options for treatment of common microbial diseases. Subinhibitory antibiotics dosing, often aid in the emergence of resistance, but its impact on pathogen's physiology and pathogenesis is not well understood. Here we investigated the effect of tunicamycin, a cell wall teichoic acid (WTA) biosynthesis inhibiting antibiotic at the subinhibitory dosage on Staphylococcus aureus and Listeria monocytogenes physiology, antibiotic cross-resistance, biofilm-formation, and virulence. Minimum inhibitory concentration (MIC) of tunicamycin to S. aureus and L. monocytogenes was 20-40 μg/ml and 2.5-5 μg/ml, respectively, and the subinhibitory concentration was 2.5-5 μg/ml and 0.31-0.62 μg/ml, respectively. Tunicamycin pre-exposure reduced cellular WTA levels by 18-20% and affected bacterial cell wall ultrastructure, cell membrane permeability, morphology, laser-induced colony scatter signature, and bacterial ability to form biofilms. It also induced a moderate level of cross-resistance to tetracycline, ampicillin, erythromycin, and meropenem for S. aureus, and ampicillin, erythromycin, vancomycin, and meropenem for L. monocytogenes. Pre-treatment of bacterial cells with subinhibitory concentrations of tunicamycin also significantly reduced bacterial adhesion to and invasion into an enterocyte-like Caco-2 cell line, which is supported by reduced expression of key virulence factors, Internalin B (InlB) and Listeria adhesion protein (LAP) in L. monocytogenes, and a S. aureus surface protein A (SasA) in S. aureus. Tunicamycin-treated bacteria or the bacterial WTA preparation suppressed NF-κB and inflammatory cytokine production (TNFα, and IL-6) from murine macrophage cell line (RAW 264.7) indicating the reduced WTA level possibly attenuates an inflammatory response. These results suggest that at the subinhibitory dosage, tunicamycin-mediated inhibition of WTA biosynthesis interferes with cell wall structure, pathogens infectivity and inflammatory response, and ability to form biofilms but promotes the development of antibiotic cross-resistance.}, } @article {pmid30033670, year = {2019}, author = {V Bondoc, KG and Lembke, C and Vyverman, W and Pohnert, G}, title = {Selective chemoattraction of the benthic diatom Seminavis robusta to phosphate but not to inorganic nitrogen sources contributes to biofilm structuring.}, journal = {MicrobiologyOpen}, volume = {8}, number = {4}, pages = {e00694}, pmid = {30033670}, issn = {2045-8827}, mesh = {Ammonium Compounds/*metabolism ; *Biofilms ; *Chemotaxis ; Diatoms/growth & development/*physiology ; Nitrates/*metabolism ; Nitrogen/metabolism ; Phosphates/*metabolism ; Silicates/metabolism ; }, abstract = {Diatoms frequently dominate marine and freshwater biofilms as major primary producers. Nutrient resources in these biofilms are patchily distributed and fluctuate dynamically over time. We recently reported that this spatially and temporally structured environment can be exploited by motile diatoms that use chemoattraction to dissolved silicate (dSi) under Si starvation. Here, we show that the behavioral response of diatoms is more complex and selective as cells are also responding to gradients of dissolved phosphate (dP) when starved in this nutrient. In contrast, neither nitrate nor ammonium (dN) triggers an attractive response under nitrogen limitation. Video monitoring and movement pattern analysis of the model diatom Seminavis robusta revealed that dP attraction is mediated by a combined chemokinetic and chemotactic response. After locating nutrient hotspots, the microalgae slow down and recover from the limitation. The fastest recovery in terms of growth was observed after dSi limitation. In agreement with the lack of directional response, recovery from dN limitation was slowest, indicating that no short-term benefit would be drawn by the algae from the location of transient hotspots of this resource. Our results highlight the ability of diatoms to adapt to nutrient limitation by active foraging and might explain their success in patchy benthic environments.}, } @article {pmid30033309, year = {2018}, author = {Naskar, A and Khan, H and Sarkar, R and Kumar, S and Halder, D and Jana, S}, title = {Anti-biofilm activity and food packaging application of room temperature solution process based polyethylene glycol capped Ag-ZnO-graphene nanocomposite.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {91}, number = {}, pages = {743-753}, doi = {10.1016/j.msec.2018.06.009}, pmid = {30033309}, issn = {1873-0191}, mesh = {Agar/chemistry ; Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Colorimetry ; *Food Packaging ; Graphite/*chemistry ; Metal Nanoparticles/chemistry/ultrastructure ; Microbial Sensitivity Tests ; Nanocomposites/*chemistry/ultrastructure ; Photoelectron Spectroscopy ; Polyethylene Glycols/*chemistry ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry ; Spectrophotometry, Ultraviolet ; Spectroscopy, Fourier Transform Infrared ; Spectrum Analysis, Raman ; Staphylococcus aureus/drug effects ; *Temperature ; Tensile Strength ; X-Ray Diffraction ; Zinc Oxide/*chemistry ; }, abstract = {Present work reports on synthesis and anti-biofilm activity as well as food packaging application of Ag-ZnO-reduce graphene oxide (rGO)-polyethylene glycol (PEG) (AZGP) nanocomposites via adopting room temperature solution process by varying silver nitrate content (up to 0.1 M) with fixed content of graphene oxide and PEG used in the precursors. Presence of Ag and ZnO nanoparticles (NPs) distributed uniformly over rGO nanosheets has been confirmed by X-ray diffraction and transmission electron microscopic analyses whereas FTIR, Raman, UV-Visible and X-ray photoelectron spectral studies have been performed to confirm the existence of chemical interaction/complexation that happened between the available oxygen functionalities of rGO and PEG with the inorganic moieties (Ag-ZnO/Zn[2+]) of AZGP samples. A formation mechanism of AZGP nanocomposite is proposed based on the experimental results. Anti-biofilm activity has been studied on Staphylococcus aureus and Pseudomonas aeruginosa bacteria to confirm the efficiency of the nanocomposites for killing the bacterial cells. It is found that 0.05 M silver nitrate based AZGP nanocomposite at 31.25 μg/mL sample dosage shows about 95% inhibition activity towards the biofilm formation as well as eradication of preformed biofilm. Also, agar based AZGP film has been fabricated and characterized by X-ray diffraction study for the purpose of food packaging application. Textural analysis of agar based film shows an enhanced film tensile strength. The film also shows an excellent antimicrobial activity even after keeping it for a prolong period of about 90 days. This cost effective simple synthesis strategy can make an avenue for development of Ag incorporated other biocompatible metal oxide based rGO-PEG nanocomposites for potential food packaging application.}, } @article {pmid30032909, year = {2018}, author = {Vysakh, A and Midhun, SJ and Jayesh, K and Jyothis, M and Latha, MS}, title = {Studies on biofilm formation and virulence factors associated with uropathogenic Escherichia coli isolated from patient with acute pyelonephritis.}, journal = {Pathophysiology : the official journal of the International Society for Pathophysiology}, volume = {25}, number = {4}, pages = {381-387}, doi = {10.1016/j.pathophys.2018.07.004}, pmid = {30032909}, issn = {0928-4680}, abstract = {The current study aims to the detection of pathogenic potential and virulence factor identification of uropathogenic Escherichia coli BRL-17 isolated from patients urine. The organism was isolated from the patient with chronic pyelonephritis. The identification of organism was done by analyzing gram staining, biochemical, 16S rDNA analysis, Raman microscopy and SEM analysis. The pathogenic potential was identified by multiplex PCR analysis of virulence factor genes like sfa, hly D, pap C. The biofilm forming ability was tested by congo red agar assay and tissue culture plate assay. The result of gram staining and biochemical analysis shows the characteristics of E-coli. The 16S rDNA analysis of the clinically isolated uropathogen showed 100% similarity with uropathogenic Escherichia coli strain. Raman microscopy and SEM confirms the organism as E-coli. The Multiplex PCR study identifies virulence genes like sfa, hly D, pap C in isolated E-coli. The presence of P fimbriae coded pap C gene, S fimbriae coded sfa gene and hemolysin-D coded hly D gene discloses its potential to cause urinary tract infection. Biofilm assay result enhances the organism's role as strong biofilm former. This biofilm forming ability of Escherichia coli strain BRL-17 made the organism to escape from host immune system and helps to colonize in bladder and kidney. This also helps to enhance the resistance to antibiotics. Our study confirms the organism as multidrug resistant, highly virulent, strong biofilm forming E-coli. The strain may be used for the development of animal models of pyelonephritis for the purpose of drug discovery.}, } @article {pmid30032398, year = {2018}, author = {Benslim, A and Mezaache-Aichour, S and Haichour, N and Aissat, K and Zerroug, MM}, title = {Biofilm formation and regulation of salicylic acid-inducible genes expression in Arabidopsis by Algerian indigenous bacteria from wheat and potatoes rhizospheres in semi-arid Sétif region.}, journal = {Archives of microbiology}, volume = {200}, number = {9}, pages = {1395-1405}, doi = {10.1007/s00203-018-1556-5}, pmid = {30032398}, issn = {1432-072X}, support = {PNR project no: 1/u19/332//Ministère de l'Enseignement Supérieur et de la recherche scientifique, République de l'Algérie/ ; }, mesh = {Algeria ; Arabidopsis/genetics/*metabolism/*microbiology ; Bacillus/classification/*isolation & purification ; Biofilms/growth & development ; Fusarium/classification/*isolation & purification ; Gene Expression ; Gene Expression Regulation, Plant/*genetics ; Lipopeptides ; Phytophthora/classification/*isolation & purification ; Plant Diseases/microbiology ; Pseudomonas/classification/*isolation & purification ; Rhizosphere ; Salicylic Acid/*metabolism ; Solanum tuberosum/metabolism ; Triticum ; }, abstract = {45 bacterial isolates from potatoes and wheat rhizospheres near Sétif (Algeria) pre-selected for their antagonistic activity against three fungal plant pathogens, two necrotrophic Fusarium solani var. coeruleum and Phytophtora infestans, and a systemic F. oxysporum f. sp. albedinis. Molecular typing of the isolates showed abundance of Bacillus compared to Pseudomonas. Some of the tested strains have shown very high biofilm formation. Among the 24 Gram-positive bacilli screened for four cyclic lipopeptides genes, some isolates harbor two or more genes, while others have a single gene or have none. Four selected isolates were able to regulate the expression of six defense-related genes in Arabidopsis and produce salicylic acid. Upon the features assessed in this study, strain B. amyloliquefaciens A16 was selected for a subsequent use as seed treatment and biocontrol agent in semi-arid region fields. This strain showed important biofilm formation, regulation of Arabidopsis defenses, and harbored three cLPs genes.}, } @article {pmid30031999, year = {2018}, author = {Díez, S and Giaggio, R}, title = {Do biofilms affect the measurement of mercury by the DGT technique? Microcosm and field tests to prevent biofilm growth.}, journal = {Chemosphere}, volume = {210}, number = {}, pages = {692-698}, doi = {10.1016/j.chemosphere.2018.07.047}, pmid = {30031999}, issn = {1879-1298}, mesh = {Biofilms/*drug effects ; *Diffusion ; Environmental Monitoring/methods ; Fresh Water/*chemistry ; Mercury/*analysis ; Metal Nanoparticles/*chemistry ; Silver/*pharmacology ; Trace Elements/pharmacokinetics ; Water Pollutants, Chemical/analysis ; }, abstract = {The diffusive gradients in thin films (DGT) technique has been used routinely for monitoring the dissolved, bioavailable fraction of trace metals in freshwater during field campaigns. Nevertheless, for long deployment times, the biofilm formed on the filter of the DGT devices restricts trace metal uptake and hence interferes with the DGT measurements. In this work, we design different experiments to evaluate the potential of silver nanoparticles (AgNPs) in preventing the formation of biofilms on in-house manufactured mercury-specific DGTs. Laboratory tests were carried out by a microcosm system in independent glass containers, where biofilms obtained from field inocula were grown for weeks. Afterward, several experiments were performed with Hg-spiked river water, biofilms and DGTs treated and untreated with AgNPs to better understand biofilm colonization, inhibition and Hg uptake. The results showed that the treatment is very useful, since the mass of the biofilm accumulated at the surface of the treated DGT is significantly (p < 0.05) lower than in control (untreated) devices. Tests in colonized environments and Hg-spiked river water showed that the Hg uptake by the treated DGT matched the theoretical values and prevented biofilm formation up to 24 days post-deployment. Conversely, in deployments longer than two weeks using the untreated DGT, measurements could be underestimated by 35%. The results in the field reveal that in sampling stations with high levels of suspended matter, the filter becomes clogged despite there being no biofilm, thereby explaining its low efficiency for the uptake of Hg. In summary, the use of AgNPs inhibits biofilm formation and their use is especially recommended in eutrophic freshwaters with low amounts of suspended particulate matter.}, } @article {pmid30031161, year = {2018}, author = {Porter, SL and Coulter, SM and Pentlavalli, S and Thompson, TP and Laverty, G}, title = {Self-assembling diphenylalanine peptide nanotubes selectively eradicate bacterial biofilm infection.}, journal = {Acta biomaterialia}, volume = {77}, number = {}, pages = {96-105}, doi = {10.1016/j.actbio.2018.07.033}, pmid = {30031161}, issn = {1878-7568}, mesh = {Animals ; Anti-Bacterial Agents/chemistry ; Anti-Infective Agents/chemistry ; Biofilms/*growth & development ; Carboxylic Acids/chemistry ; Cell Membrane/chemistry ; Cell Survival ; Dipeptides ; Drug Delivery Systems ; Fibroblasts/metabolism ; Hemolysis ; Magnetic Resonance Spectroscopy ; Mice ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Nanotubes, Peptide/*chemistry ; Permeability ; Phenylalanine/*analogs & derivatives/chemistry ; Polysaccharides/chemistry ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects ; }, abstract = {UNLABELLED: Biofilms present a major problem to industry and healthcare worldwide. Composed of a population of surface-attached microbial cells surrounded by a protective extracellular polysaccharide matrix, they are responsible for increased tolerance to antibiotics, treatment failure and a resulting rise in antimicrobial resistance. Here we demonstrate that self-assembled peptide nanostructures composed of a diphenylalanine motif provide sufficient antibacterial activity to eradicate mature biofilm forms of bacteria widely implicated in hospital infections. Modification of terminal functional groups to amino (-NH2), carboxylic acid (-COOH) or both modalities, and switch to d-isomers, resulted in changes in antibacterial selectivity and mammalian cell toxicity profiles. Of the three peptide nanotubes structures studied (NH2-FF-COOH, NH2-ff-COOH and NH2-FF-NH2), NH2-FF-COOH demonstrated the most potent activity against both planktonic (liquid, free-floating) and biofilm forms of bacteria, possessing minimal mammalian cell toxicity. NH2-FF-COOH resulted in greater than 3 Log10 CFU/mL viable biofilm reduction (>99.9%) at 5 mg/mL and total biofilm kill at 10 mg/mL against Staphylococcus aureus after 24 h exposure. Scanning electron microscopy proved that antibiofilm activity was primarily due to the formation of ion channels and/or surfactant-like action, with NH2-FF-COOH and NH2-ff-COOH capable of degrading the biofilm matrix and disrupting cell membranes, leading to cell death in Gram-positive bacterial isolates. Peptide-based nanotubes are an exciting platform for drug delivery and engineering applications. This is the first report of using peptide nanotubes to eradicate bacterial biofilms and provides evidence of a new platform that may alleviate their negative impact throughout society.

STATEMENT OF SIGNIFICANCE: We outline, for the first time, the antibiofilm activity of diphenylalanine (FF) peptide nanotubes. Biofilm bacteria exhibit high tolerance to antimicrobials 10-10,000 times that of free-flowing planktonic forms. Biofilm infections are difficult to treat using conventional antimicrobial agents, leading to a rise in antimicrobial resistance. We discovered nanotubes composed of NH2-FF-COOH demonstrated potent activity against staphylococcal biofilms implicated in hospital infections, resulting in complete kill at concentrations of 10 mg/mL. Carboxylic acid terminated FF nanotubes were able to destroy the exopolysaccharide architecture of staphylococcal biofilms expressing minimal toxicity, highlighting their potential for use in patients. Amidated (NH2-FF-NH2) forms demonstrated reduced antibiofilm efficacy and significant toxicity. These results contribute significantly to the development of innovative antibacterial technologies and peptide nanomaterials.}, } @article {pmid30030225, year = {2018}, author = {Thompson, CM and Marsden, AE and Tischler, AH and Koo, J and Visick, KL}, title = {Vibrio fischeri Biofilm Formation Prevented by a Trio of Regulators.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {19}, pages = {}, pmid = {30030225}, issn = {1098-5336}, support = {R01 GM114288/GM/NIGMS NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/enzymology/genetics/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Decapodiformes/*microbiology ; *Gene Expression Regulation, Bacterial ; Hawaii ; Histidine Kinase/genetics/*metabolism ; Phosphoric Monoester Hydrolases/genetics/*metabolism ; Symbiosis ; }, abstract = {Biofilms, complex communities of microorganisms surrounded by a self-produced matrix, facilitate attachment and provide protection to bacteria. A natural model used to study biofilm formation is the symbiosis between Vibrio fischeri and its host, the Hawaiian bobtail squid, Euprymna scolopes Host-relevant biofilm formation is a tightly regulated process and is observed in vitro only with strains that have been genetically manipulated to overexpress or disrupt specific regulators, primarily two-component signaling (TCS) regulators. These regulators control biofilm formation by dictating the production of the symbiosis polysaccharide (Syp-PS), the major component of the biofilm matrix. Control occurs both at and below the level of transcription of the syp genes, which are responsible for Syp-PS production. Here, we probed the roles of the two known negative regulators of biofilm formation, BinK and SypE, by generating double mutants. We also mapped and evaluated a point mutation using natural transformation and linkage analysis. We examined traditional biofilm formation phenotypes and established a new assay for evaluating the start of biofilm formation in the form of microscopic aggregates in shaking liquid cultures, in the absence of the known biofilm-inducing signal calcium. We found that wrinkled colony formation is negatively controlled not only by BinK and SypE but also by SypF. SypF is both required for and inhibitory to biofilm formation. Together, these data reveal that these three regulators are sufficient to prevent wild-type V. fischeri from forming biofilms under these conditions.IMPORTANCE Bacterial biofilms promote attachment to a variety of surfaces and protect the constituent bacteria from environmental stresses, including antimicrobials. Understanding the mechanisms by which biofilms form will promote our ability to resolve them when they occur in the context of an infection. In this study, we found that Vibrio fischeri tightly controls biofilm formation using three negative regulators; the presence of a single one of these regulators was sufficient to prevent full biofilm development, while disruption of all three permitted robust biofilm formation. This work increases our understanding of the functions of specific regulators and demonstrates the substantial negative control that one benign microbe exerts over biofilm formation, potentially to ensure that it occurs only under the appropriate conditions.}, } @article {pmid30030124, year = {2018}, author = {Ionescu, AC and Cazzaniga, G and Ottobelli, M and Ferracane, JL and Paolone, G and Brambilla, E}, title = {In vitro biofilm formation on resin-based composites cured under different surface conditions.}, journal = {Journal of dentistry}, volume = {77}, number = {}, pages = {78-86}, doi = {10.1016/j.jdent.2018.07.012}, pmid = {30030124}, issn = {1879-176X}, mesh = {*Biofilms ; *Composite Resins ; *Dental Materials ; Materials Testing ; Microscopy, Electron, Scanning ; *Streptococcus mutans ; Surface Properties ; }, abstract = {OBJECTIVES: The interfacial conditions occurring during light-curing procedures of resin-based composites (RBCs) influence their surface properties and therefore the biological behavior of the material. This study aimed to evaluate the influence of different surface curing conditions on in vitro biofilm formation by Streptococcus mutans and mixed oral microflora, in the presence or absence of surface salivary pre-conditioning.

METHODS: Two nanohybrid RBCs and four interfacial curing conditions (open air, argon, nitrogen and glycerin) were evaluated. Surface roughness (SR), surface elemental composition (energy-dispersive X-ray spectrometry, EDS) and biofilm formation (S. mutans and oral microcosm) were assessed. Surfaces were observed using scanning electron microscopy (SEM). Microbiological tests were performed with and without saliva pre-conditioning of the surfaces. EDS analysis was performed before and after biofilm formation, and biofilm morphology was evaluated using confocal laser scanning microscopy (CLSM). Data were analyzed using multi-way ANOVA and Tukey post-hoc test (p < 0.05).

RESULTS: Interfacial curing conditions significantly influenced SR depending on the tested RBC. EDS analysis showed that surface elemental composition was significantly influenced by the interfacial curing condition depending on the tested RBC. Interfacial curing conditions significantly influenced biofilm formation in both microbiological models in the absence of saliva pre-conditioning, depending on the tested RBC, whereas saliva pre-conditioning abrogated these effects.

CONCLUSIONS: Surface curing conditions significantly impacted biofilm formation in a material-dependent manner, which was abrogated when surfaces were pre-conditioned with saliva.

CLINICAL SIGNIFICANCE: Curing under glycerin did not improve the microbiological performances of the tested RBCs. These results, needing to be confirmed by in vivo data, have the potential to simplify operative procedures in restorative dentistry.}, } @article {pmid30028928, year = {2018}, author = {Braga, AS and Degand, GB and Pires, JG and Santos, DMSD and Magalhães, AC}, title = {Effect of oral antimicrobial mouthrinses containing alcohol on viability of Streptococcus mutans and microcosm biofilm and on the prevention of enamel caries lesions.}, journal = {American journal of dentistry}, volume = {31}, number = {3}, pages = {121-125}, pmid = {30028928}, issn = {0894-8275}, mesh = {Animals ; *Anti-Infective Agents/pharmacology ; Biofilms ; Cattle ; *Dental Caries/prevention & control ; Dental Enamel ; Humans ; *Streptococcus mutans/drug effects ; *Tooth Demineralization ; }, abstract = {PURPOSE: To evaluate the effect of PerioGard, Listerine, Noplak, Malvatricin and Cepacol commercial mouthrinses containing alcohol on the viability of Streptococcus mutans strain and of a microcosm biofilm and on the prevention of enamel demineralization.

METHODS: The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined against S. mutans (ATCC 25175). Microcosm biofilm formed from human saliva mixed with McBain saliva was created on bovine enamel for 5 days. From the 2nd to the 5th day, the enamel samples were exposed to McBain with 0.2% sucrose and to the mouthrinses (1 x 60 seconds). The biofilm viability was determined by fluorescence and the enamel demineralization by TMR.

RESULTS: The lowest MIC and MBC values were observed for Cepacol, while the highest values were found for Listerine. The mouthrinses significantly increased the number of dead bacteria in biofilm, varying from 38.0± 11.2% (Noplak) to 58.5± 13.9% (Listerine), compared to control (12.7± 10.6%), except Periogard (30.1± 12.4%). All mouthrinses reduced mineral loss (P< 0.0001), but only Noplak and Cepacol were able to significantly reduce lesion depth. Cepacol and Noplak presented the best anti-caries effect under this experimental model.

CLINICAL SIGNIFICANCE: This study shows that the anti-caries potential may vary between the commercial mouthrinses, which should be taken into account for their prescription.}, } @article {pmid30028051, year = {2020}, author = {Alzayer, YM and Gomez, GF and Eckert, GJ and Levon, JA and Gregory, RL}, title = {The Impact of Nicotine and Cigarette Smoke Condensate on Metabolic Activity and Biofilm Formation of Candida albicans on Acrylic Denture Material.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {29}, number = {2}, pages = {173-178}, doi = {10.1111/jopr.12945}, pmid = {30028051}, issn = {1532-849X}, mesh = {Antifungal Agents ; Biofilms ; *Candida albicans ; Dentures ; *Nicotine ; Polymethyl Methacrylate ; Smoking ; Tobacco ; }, abstract = {PURPOSE: Smokers have increased denture stomatitis caused primarily by Candida albicans. The primary aim of this study was to demonstrate the impact of a wide range of nicotine and cigarette smoke condensate (CSC) concentrations on biofilm formation and metabolic activity of C. albicans on acrylic denture material.

MATERIALS AND METHODS: C. albicans (ATCC strain 10231) was used. Standardized denture acrylic (PMMA) specimens (total of 135 specimens) were incubated with C. albicans and exposed to nicotine and CSC at different concentrations (0, 0.25, 0.5, 1, 2, 4, 8, 16, and 32 mg/ml) and (0, 0.25, 0.5, 1, 2, and 4 mg/ml), respectively. For each experiment, 3 samples per nicotine and CSC concentration and a total of 45 specimens (27 specimens for the nicotine and 18 specimens for the CSC-treated samples) were used and were selected randomly for each group. The control group consisted of 0 mg/ml of nicotine or CSC. The viability of C. albicans was measured using spiral plating on blood agar plates. The effect of nicotine and CSC concentrations on planktonic cells was were measured using a microplate reader. Metabolic activity of 24-hour-old established C. albicans biofilm exposed to nicotine and CSC for 24 hours in microtiter plates was determined using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) reduction assay.

RESULTS: The viability of C. albicans increased concomitant with increasing concentrations of CSC and nicotine, particularly at 0.5 and 2 mg/ml, respectively. Concentrations of CSC and nicotine above this resulted in an inhibitory effect on C. albicans viability. CSC and nicotine at 4 and 16 mg/ml, respectively, increased C. albicans biofilm metabolic activity.

CONCLUSION: Nicotine and CSC up to certain concentrations caused increases in biofilm formation, metabolic activity, viability, and planktonic cell absorbance of C. albicans. This in vitro study demonstrates the effectiveness of tobacco on promoting the growth of C. albicans and suggests their potential contributing factor in C. albicans biofilm related infections in smokers.}, } @article {pmid30026732, year = {2018}, author = {Pompilio, A and Geminiani, C and Bosco, D and Rana, R and Aceto, A and Bucciarelli, T and Scotti, L and Di Bonaventura, G}, title = {Electrochemically Synthesized Silver Nanoparticles Are Active Against Planktonic and Biofilm Cells of Pseudomonas aeruginosa and Other Cystic Fibrosis-Associated Bacterial Pathogens.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1349}, pmid = {30026732}, issn = {1664-302X}, abstract = {A novel, electrochemically synthesized, silver nanoparticles (AgNPs) formulation was evaluated in vitro against Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Staphylococcus aureus strains from cystic fibrosis (CF) patients. AgNPs were particularly active against P. aeruginosa and B. cepacia planktonic cells (median MIC: 1.06 and 2.12 μg/ml, respectively) by a rapid, bactericidal and concentration-dependent effect. AgNPs showed to be particularly effective against P. aeruginosa and S. aureus biofilm causing a viability reduction ranging from 50% (1×MIC) to >99.9% (4×MIC). Electron microscopy showed that AgNPs deconstruct extracellular matrix of P. aeruginosa biofilm, and accumulate at the cell surface causing cell death secondary to membrane damage. Compared to Tobramycin, AgNPs showed comparable, or even better, activity against planktonic and biofilm P. aeruginosa cells. AgNPs at concentrations effective against B. cepacia and P. aeruginosa were not toxic to G. mellonella larvae. Our silver-based formulation might be an alternative to antibiotics in CF patients. Further in vitro and in vivo studies are warranted to confirm this therapeutic potential.}, } @article {pmid30026003, year = {2018}, author = {Ledwoch, K and Dancer, SJ and Otter, JA and Kerr, K and Roposte, D and Rushton, L and Weiser, R and Mahenthiralingam, E and Muir, DD and Maillard, JY}, title = {Beware biofilm! Dry biofilms containing bacterial pathogens on multiple healthcare surfaces; a multi-centre study.}, journal = {The Journal of hospital infection}, volume = {100}, number = {3}, pages = {e47-e56}, doi = {10.1016/j.jhin.2018.06.028}, pmid = {30026003}, issn = {1532-2939}, mesh = {Bacteria/*classification/*isolation & purification ; Bacteriological Techniques ; *Biofilms ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal Spacer/chemistry/genetics ; *Dehydration ; *Environmental Microbiology ; *Hospitals ; Humans ; Microscopy, Electron, Scanning ; Polymerase Chain Reaction ; Prevalence ; Sequence Analysis, DNA ; United Kingdom ; }, abstract = {BACKGROUND: Wet biofilms associated with medical devices have been widely studied and their link with healthcare-associated infections (HCAIs) is well recognized. Little attention has been paid to the presence of dry biofilms on environmental surfaces in healthcare settings.

AIM: To investigate the occurrence, prevalence, and diversity of dry biofilms on hospital surfaces.

METHODS: Sixty-one terminally cleaned items were received from three different UK hospitals. The presence of dry biofilm was investigated using culture-based methods and scanning electron microscopy (SEM). Bacterial diversity within biofilms was investigated using ribosomal RNA intergenic spacer analysis (RISA)-polymerase chain reaction and next-generation sequencing.

FINDINGS: Multi-species dry biofilms were recovered from 95% of 61 samples. Abundance and complexity of dry biofilms were confirmed by SEM. All biofilms harboured Gram-positive bacteria including pathogens associated with HCAI; 58% of samples grew meticillin-resistant Staphylococcus aureus. Dry biofilms had similar physical composition regardless of the type of items sampled or the ward from which the samples originated. There were differences observed in the dominance of particular species: dry biofilms from two hospitals contained mostly staphylococcal DNA, whereas more Bacillus spp. DNA was found on surfaces from the third hospital.

CONCLUSION: The presence of dry biofilms harbouring bacterial pathogens is virtually universal on commonly used items in healthcare settings. The role of dry biofilms in spreading HCAIs may be underestimated. The risk may be further exacerbated by inefficient cleaning and disinfection practices for hospital surfaces.}, } @article {pmid30025265, year = {2018}, author = {Long, M and Ilhan, ZE and Xia, S and Zhou, C and Rittmann, BE}, title = {Complete dechlorination and mineralization of pentachlorophenol (PCP) in a hydrogen-based membrane biofilm reactor (MBfR).}, journal = {Water research}, volume = {144}, number = {}, pages = {134-144}, doi = {10.1016/j.watres.2018.06.071}, pmid = {30025265}, issn = {1879-2448}, mesh = {Biofilms ; *Bioreactors/microbiology ; Denitrification ; Equipment Design ; Halogenation ; Hydrogen/chemistry/metabolism ; Membranes, Artificial ; Nitrates/chemistry/metabolism ; Pentachlorophenol/*chemistry/metabolism ; Phenol/chemistry/metabolism ; Sulfates/chemistry/metabolism ; Water Pollutants, Chemical/chemistry/metabolism ; Water Purification/*instrumentation/methods ; }, abstract = {Complete biodegradation and mineralization of pentachlorophenol (PCP), a priority pollutant in water, is challenging for water treatment. In this study, a hydrogen (H2)-based membrane biofilm reactor (MBfR) was applied to treat PCP, along with nitrate and sulfate, which often coexist in contaminated groundwater. Throughout 120-days of continuous operation, almost 100% of up to 10 mg/L PCP was removed with minimal intermediate accumulation and in parallel with complete denitrification of 20 mg-N/L nitrate. PCP initially was reductively dechlorinated to phenol, which was then mineralized to CO2 through pathways that began with aerobic activation via monooxygenation by Xanthobacter and anaerobic activation via carboxylation by Azospira and Thauera. Sulfur cycling induced by SO4[2-] reduction affected the microbial community: The dominant bacteria became sulfate-reducers Desulfomicrobium, sulfur-oxidizers Sulfuritalea and Flavobacterium. This study provides insights and a promising technology for bioremediation of water contaminated with PCP, nitrate, and sulfate.}, } @article {pmid30024592, year = {2018}, author = {Liu, K and Hou, BX}, title = {The regulation of DLTA gene in bacterial growth and biofilm formation by Parvimonas micra.}, journal = {European review for medical and pharmacological sciences}, volume = {22}, number = {13}, pages = {4033-4044}, doi = {10.26355/eurrev_201807_15390}, pmid = {30024592}, issn = {2284-0729}, mesh = {Biofilms/*growth & development ; Dental Plaque/*microbiology ; Humans ; Lipopolysaccharides/*metabolism ; Teichoic Acids/*metabolism ; }, abstract = {OBJECTIVE: To evaluate the effect of dltA-deficient mutant on the bacterial growth and biofilm formation by P. micra ATCC 33270. Parvimonas micra contributes to many human polymicrobial infections, and is common in dental plaque biofilms of patients with periodontal and endodontic conditions. Lipoteichoic acid (LTA) performs several functions in gram-positive bacteria, including maintenance of cationic homeostasis and modulation of autolytic activities. The activation of dltA gene expression protects LTA expressing gram-positive bacteria from innate immune anti-microbial defense.

MATERIALS AND METHODS: Deficient mutant of the dltA gene was created from P. micra ATCC 33270 by homologous recombination. Colony-forming units (CFUs) and turbidity helped estimate the growth of P. micra. Crystal violet staining, Confocal Scanning Laser Microscopy (CSLM) and Scanning Electron Microscopy (SEM) evaluated biofilm mass and structure.

RESULTS: P. micra ATCC 33270 with dltA-deficient mutant was successfully established. CFUs of the wild-type strains were significantly higher than that of the dltA-deficient mutant strains after 24 h, 48 h, 72 h and 7 d culture (all p < 0.05). The growth rate of dltA-deficient mutant strains was significantly lower than their wild-type counterparts. Furthermore, crystal violet staining showed that the dltA mutant formed significantly less biofilm as compared to wild-type strains. The dltA-deficient mutant synthesized a thin and incomplete biofilm after incubation for 48 h. With increasing incubation time, all biofilm units were seen to shrink, and this structure almost disappeared after 7 days of culture as observed by CSLM and SEM.

CONCLUSIONS: The dltA gene is associated with bacterial growth and biofilm formation by P. micra ATCC 33270.}, } @article {pmid30024267, year = {2018}, author = {Korabliovienė, J and Mauricas, M and Ambrozevičienė, Č and Valius, M and Kaupinis, A and Čaplinskas, S and Korabliov, P}, title = {Mycobacteria produce proteins involved in biofilm formation and growth-affecting processes.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {65}, number = {3}, pages = {405-418}, doi = {10.1556/030.65.2018.033}, pmid = {30024267}, issn = {1217-8950}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Humans ; Mycobacterium avium/genetics/growth & development/*physiology ; Mycobacterium bovis/genetics/growth & development/*physiology ; }, abstract = {The aim of this study was to determine the effect of mycobacterial proteins on mycobacterial biofilm formation and growth processes. We separated growth-affecting proteins (GEPs) from wild type of Mycobacterium bovis and ATCC strain of Mycobacterium avium subsp. avium. Our results showed that these mycobacteria-secreted GEPs are involved in biofilm formation, growth stimulatory, and inhibitory processes. Our findings suggest that GEP stimulated M. avium subsp. avium growth in vitro. Stimulation process was observed in mycobacteria affected with GEP extracted from M. avium subsp. avium. We found that both GEPs inhibited the growth of the M. bovis. Optical density measurement and visual analysis confirm that GEP plays an important role in biofilm formation process. Most of M. bovis GEP are associated with the type VII secretion and general secretion pathways. Our results contribute to a better understanding of the mechanisms underlying mycobacterial biofilm formation and growth-affecting processes and better characterization of mycobacterial proteins and their functions. It is noteworthy that this finding represents the first demonstration of GEP-mediated growth effects on a solid and liquid medium.}, } @article {pmid30023786, year = {2018}, author = {Sambalova, O and Thorwarth, K and Heeb, NV and Bleiner, D and Zhang, Y and Borgschulte, A and Kroll, A}, title = {Carboxylate Functional Groups Mediate Interaction with Silver Nanoparticles in Biofilm Matrix.}, journal = {ACS omega}, volume = {3}, number = {1}, pages = {724-733}, pmid = {30023786}, issn = {2470-1343}, abstract = {Biofilms causing medical conditions or interfering with technical applications can prove undesirably resistant to silver nanoparticle (AgNP)-based antimicrobial treatment, whereas beneficial biofilms may be adversely affected by the released silver nanoparticles. Isolated biofilm matrices can induce reduction of silver ions and stabilization of the formed nanosilver, thus altering the exposure conditions. We thus study the reduction of silver nitrate solution in model experiments under chemically defined conditions as well as in stream biofilms. Formed silver nanoparticles are characterized by state-of-the art methods. We find that isolated biopolymer fractions of biofilm organic matrix are capable of reducing ionic Ag, whereas other isolated fractions are not, meaning that biopolymer fractions contain both reducing agent and nucleation seed sites. In all of the investigated systems, we find that silver nanoparticle-biopolymer interface is dominated by carboxylate functional groups. This suggests that the mechanism of nanoparticle formation is of general nature. Moreover, we find that glucose concentration within the biofilm organic matrix correlates strongly with the nanoparticle formation rate. We propose a simple mechanistic explanation based on earlier literature and the experimental findings. The observed generality of the extracellular polymeric substance/AgNP system could be used to improve the understanding of impact of Ag[+] on aqueous ecosystems, and consequently, to develop biofilm-specific medicines and bio-inspired water decontaminants.}, } @article {pmid30023754, year = {2017}, author = {Freudenthal, O and Quilès, F and Francius, G}, title = {Discrepancies between Cyclic and Linear Antimicrobial Peptide Actions on the Spectrochemical and Nanomechanical Fingerprints of a Young Biofilm.}, journal = {ACS omega}, volume = {2}, number = {9}, pages = {5861-5872}, pmid = {30023754}, issn = {2470-1343}, abstract = {Antimicrobial peptides (AMPs) are currently known for their potential as an alternative to conventional antibiotics and new weapons against drug-resistant bacteria and biofilms. In the present work, the mechanism of action of a cyclic (colistin) and a linear (catestatin) AMP on a young E. coli biofilm was deciphered from the molecular to the cellular scale. To this end, infrared spectroscopy (attenuated total reflection-Fourier transform infrared) assisted by chemometric analysis was combined with fluorescence and atomic force microscopies to address the very different behaviors of both AMPs. Indeed, the colistin dramatically damaged the bacterial cell wall and the metabolism even though its action was not homogeneous over the whole bacterial population and repopulation can be observed after peptide removal. Conversely, catestatin did not lead to major damages in the bacterial morphology but its action was homogeneous over the whole bacterial population and the cells were unable to regrow after the peptide treatment. Our results strongly suggested that contrary to the cyclic molecule, the linear one is able to cause irreversible damages in the bacterial membrane concomitantly to a strong impact on the bacterial metabolism.}, } @article {pmid30023683, year = {2017}, author = {Yadav, N and Dubey, A and Shukla, S and Saini, CP and Gupta, G and Priyadarshini, R and Lochab, B}, title = {Graphene Oxide-Coated Surface: Inhibition of Bacterial Biofilm Formation due to Specific Surface-Interface Interactions.}, journal = {ACS omega}, volume = {2}, number = {7}, pages = {3070-3082}, pmid = {30023683}, issn = {2470-1343}, abstract = {Graphene oxide (GO) is a promising and remarkable nanomaterial that exhibits antimicrobial activity due to its specific surface-interface interactions. In the present work, for the first time, we have reported the antibacterial activity of GO-coated surfaces prepared by two different methods (Hummers' and improved, i.e., GOH and GOI) against bacterial biofilm formation. The bacterial toxicity of the deposited GO-coated surfaces was investigated for both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) models of bacteria. The mechanism of inhibition is different on the coated surface than that in suspension, as determined by measurement of the percentage inhibition of biofilm formation, Ellman's assay, and colony forming unit (CFU) studies. The difference in the nature, degree of oxidative functionalities, and size of the synthesized GO nanoparticles mitigates biofilm formation. To better understand the antimicrobial mechanism of GO when coated on surfaces, we were able to demonstrate that beside reactive oxygen species-mediated oxidative stress, the physical properties of the GO-coated substrate effectively inactivate bacterial cell proliferation, which forms biofilms. Light and atomic force microscopy (AFM) images display a higher inhibition in the proliferation of planktonic cells in Gram-negative bacteria as compared to that in Gram-positive bacteria. The existence of a smooth surface with fewer porous domains in GOI inhibits biofilm formation, as demonstrated by optical microscopy and AFM images. The oxidative stress was found to be lower in the coated surface as compared to that in the suspensions as the latter enables exposure of both a large fraction of the active edges and functionalities of the GO sheets. In suspension, GOH is selective against S. aureus whereas GOI showed inhibition toward E. coli. This study provides new insights to better understand the bactericidal activity of GO-coated surfaces and contributes to the design of graphene-based antimicrobial surface coatings, which will be valuable in biomedical applications.}, } @article {pmid30022542, year = {2019}, author = {Ardon, CB and Prens, EP and Fuursted, K and Ejaz, RN and Shailes, J and Jenssen, H and Jemec, GBE}, title = {Biofilm production and antibiotic susceptibility of Staphylococcus epidermidis strains from Hidradenitis Suppurativa lesions.}, journal = {Journal of the European Academy of Dermatology and Venereology : JEADV}, volume = {33}, number = {1}, pages = {170-177}, doi = {10.1111/jdv.15183}, pmid = {30022542}, issn = {1468-3083}, support = {//Roskilde University doctoral school programme for Basic and Clinical Microbiology and Zealand University (former Roskilde) Hospital/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Clindamycin/pharmacology ; Doxycycline/pharmacology ; Drug Resistance, Bacterial ; Hidradenitis Suppurativa/*microbiology ; Humans ; Microbial Sensitivity Tests ; Rifampin/pharmacology ; Staphylococcus epidermidis/*drug effects/*growth & development/isolation & purification ; Tetracycline/pharmacology ; }, abstract = {BACKGROUND: An aberrant interaction between commensal skin bacteria and the host skin immune system is considered important in the pathogenesis of hidradenitis suppurativa (HS).

OBJECTIVE: In this study, we investigated the antibiotic susceptibility and biofilm-forming capabilities of S. epidermidis strains isolated from HS patients.

METHODS: Skin biopsies were taken from active HS lesions such as inflammatory nodules and/or sinuses and non-involved skin from 26 patients and cultured under optimal microbiological conditions for 24 h. Planktonic growth, biofilm production, antibiotic susceptibility and biofilm eradication by clindamycin, doxycycline, rifampicin and tetracycline were tested including a laboratory control strain of S. epidermidis for reference.

RESULTS: Staphylococcus epidermidis was cultured in 16 of 26 HS patients (62%). In total 27 different S. epidermidis isolates were identified; 16 (59%) from non-involved skin and 11 (41%) from HS lesions. All bacterial strains showed planktonic growth. Twenty-four of 27 (89%) isolates were strong biofilm producers in vitro. The biofilm-forming capability varied amongst the strains from non-involved skin and lesional skin. Twenty-four strains had an intermediate to resistant antibiotic susceptibility to clindamycin (89%). Rifampicin was the most effective antibiotic at inhibiting planktonic growth and at eradication of biofilm (P < 0.05).

CONCLUSION: We observed a slight increase in S. epidermidis virulence, characterized by resistance to commonly used antibiotics, increased biofilm production and resistance to biofilm eradication. In particular, the reduced sensitivity to tetracycline and clindamycin, two standard antibiotics in the treatment of HS, is alarming. Rifampicin, also important in HS treatment, showed the greatest efficacy at eradicating the biofilm at low MIC concentrations.}, } @article {pmid30022269, year = {2019}, author = {Jardine, AP and Montagner, F and Quintana, RM and Zaccara, IM and Kopper, PMP}, title = {Antimicrobial effect of bioceramic cements on multispecies microcosm biofilm: a confocal laser microscopy study.}, journal = {Clinical oral investigations}, volume = {23}, number = {3}, pages = {1367-1372}, pmid = {30022269}, issn = {1436-3771}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Bismuth/pharmacology ; Calcium Compounds/pharmacology ; Dental Cements/*pharmacology ; Humans ; Materials Testing ; Microscopy, Confocal ; Oxides/pharmacology ; Silicates/pharmacology ; }, abstract = {OBJECTIVES: To assess the viability of multispecies microcosm biofilm after contact with NeoMTA Plus, Biodentine, and MTA Angelus.

MATERIALS AND METHODS: Fifty-four human dentin blocks (4 × 5 × 4 mm) were allocated to Hawley retainers, worn by six volunteers for 72 h. The blocks were then individually incubated in BHI broth for 21 days at 37 °C. At the end of experimental time for biofilm growth, the samples were randomly divided into four groups (n = 12): NeoMTA Plus, Biodentine, MTA Angelus, and negative control. The materials were placed in contact with the blocks. All samples were placed in cell-culture plate wells and incubated in BHI broth for 7 days at 37 °C. One sample from each volunteer (n = 6) was analyzed by SEM to describe the biofilm morphology. CLSM was performed to determine the percentage of viable biofilm biovolume. The data were statistically analyzed by one-way ANOVA and Tukey's multiple comparison test (α = 5%).

RESULTS: SEM showed biofilm formed by spherical and rod-shaped bacteria surrounded by an extracellular matrix. No material was able to kill all biofilm cells, and all groups had more than 50% of viable bacteria. NeoMTA Plus was significantly different from the negative control group (P < .05).

CONCLUSIONS: All tested materials were not effective against multispecies microcosm biofilm.

CLINICAL RELEVANCE: NeoMTA Plus, Biodentine, and MTA Angelus were not effective against multispecies microcosm biofilm. It is essential to understand that these bioceramic cements are indicated for infected clinical situations. Thus, complementary disinfection procedures should be conducted prior to filling with these materials.}, } @article {pmid30021200, year = {2019}, author = {Maske, TT and Kuper, NK and Cenci, MS and Huysmans, MDNJM}, title = {Chlorhexidine, a Matrix Metalloproteinase Inhibitor and the Development of Secondary Caries Wall Lesions in a Microcosm Biofilm Model.}, journal = {Caries research}, volume = {53}, number = {1}, pages = {107-117}, doi = {10.1159/000490195}, pmid = {30021200}, issn = {1421-976X}, mesh = {Analysis of Variance ; Anti-Infective Agents, Local/*therapeutic use ; Bacterial Load/drug effects ; Biofilms/*drug effects ; Chlorhexidine/*therapeutic use ; Composite Resins/chemistry ; Dental Caries/diagnostic imaging/*drug therapy ; Dentin/*drug effects/pathology ; Dentin-Bonding Agents/chemistry ; Humans ; Linear Models ; Male ; Matrix Metalloproteinase Inhibitors/*therapeutic use ; Microradiography ; Resin Cements ; Saliva ; Young Adult ; }, abstract = {This study investigated the role of a matrix metalloproteinase (MMP) inhibitor (CHX 2%) in the development of secondary caries wall lesions in different interface conditions with small (run 1) and wider gaps (run 2). Dentin discs were restored and pretreated with or without CHX 2%. In run 1, interfaces were made with gaps of 30, 60, or 90 µm. Interfaces with composite placed directly onto the dentin were either bonded (Adper Single Bond 2) or not bonded. In run 2, interfaces were made with gaps of 100 µm, with or without adhesive on the composite side (CLEARFIL SE Bond). Interfaces were either bonded or not bonded, as in run 1. Microcosm biofilms were grown on dentin-composite samples for 14 days. Caries lesion outcomes were analyzed by transversal wavelength-independent microradiography at 3 locations: the outer surface, and the interface wall at a distance of 200 and 500 µm from the gap entrance. Linear regression analyses showed that pretreatment with MMP inhibitor did not influence progression of the wall lesion at any location (p ≥ 0.218). Interfaces with intentional gaps showed positive and significant effect on the wall lesion progression at 200 µm from the gap entrance (p ≤ 0.005). A small trend of increase in wall lesion development was observed at the 200-µm location when bonding was present on the composite side. In conclusion, the dentin pretreatment with CHX 2% was not able to slow down the development of secondary caries wall lesions in small and wide gaps in this biofilm model.}, } @article {pmid30018971, year = {2018}, author = {Cerioli, MF and Moliva, MV and Cariddi, LN and Reinoso, EB}, title = {Effect of the Essential Oil of Minthostachys verticillata (Griseb.) Epling and Limonene on Biofilm Production in Pathogens Causing Bovine Mastitis.}, journal = {Frontiers in veterinary science}, volume = {5}, number = {}, pages = {146}, pmid = {30018971}, issn = {2297-1769}, abstract = {Bovine mastitis causes large annual economic losses around the world. Different microorganisms are associated with the disease. The capacity of pathogens to adhere to bovine mammary epithelial cells is associated with biofilm production which leads to antibiotic resistance. Research is now leading to search alternative control methods and medicinal plants constitute a natural, safe, effective and inexpensive option. Minthostachys verticillata is an autochthonous medicinal plant of Argentina with multiple ethnobotanical properties. In a previous study, we demonstrated that the essential oil (EO) of this species and limonene, one of its compounds, inhibited the growth of mastitis pathogens. The objective of the present work was to determine the inhibitory effect of the essential oil of M. verticillata and limonene, on biofilm formation and on mature biofilm produced by pathogens isolated from bovine mastitis. Time kill assay and bacterial lysis were also determined. Furthermore, RAPD-PCR assays were performed to determine changes in bacterial DNA after EO and limonene exposition. Bacterial isolates were identified as Escherichia coli (EC3 and EC9), Bacillus pumilus (BP5, BP6, and BP7) and Enterococcus faecium (EF1) by rRNA 16S sequencing and MALDI-TOF MS. All the strains were able to form biofilm. Addition of both lactose and sucrose did not affect biofilm production. MIC values for EO were 3.6 mg/ml for E. faecium; 0.9 mg/ml for E. coli (EC3), 14.5 mg/ml for E. coli (EC9), 1.8 mg/ml for B. pumilus (BP7), 3.63 mg/ml for B. pumilus (BP6) and 29.0 mg/ml for B. pumilus (BP7). MIC values for limonene were 6.6 mg/ml for B. pumilus (BP6) and 105 mg/ml for B. pumilus (BP5). These results demonstrated that EO was more effective than limonene, showing also bactericidal action against E. faecium (minimal inhibitory concentration (MBC) = 29.0 mg/ml). This result was corroborated by time of death assay, observing a cell decrease after at 6 h, and then by bacterial lysis assay. Both EO and limonene affected mature biofilm of isolated strains. The results contribute to the study of EO and limonene which may serve as a therapy against bovine mastitis pathogens inhibiting the development of pathogenic bacteria.}, } @article {pmid30018606, year = {2018}, author = {Wilkinson, HN and Iveson, S and Catherall, P and Hardman, MJ}, title = {A Novel Silver Bioactive Glass Elicits Antimicrobial Efficacy Against Pseudomonas aeruginosa and Staphylococcus aureus in an ex Vivo Skin Wound Biofilm Model.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1450}, pmid = {30018606}, issn = {1664-302X}, support = {MR/L010267/1/MRC_/Medical Research Council/United Kingdom ; MR/L010267/2/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Biofilm infection is now understood to be a potent contributor to the recalcitrant nature of chronic wounds. Bacterial biofilms evade the host immune response and show increased resistance to antibiotics. Along with improvements in antibiotic stewardship, effective new anti-biofilm therapies are urgently needed for effective wound management. Previous studies have shown that bioactive glass (Bg) is able to promote healing with moderate bactericidal activity. Here we tested the antimicrobial efficacy of a novel BG incorporating silver (Bg[Ag]), against both planktonic and biofilm forms of the wound-relevant bacteria Pseudomonas aeruginosa and Staphylococcus aureus. Bg[Ag] was stable, long lasting, and potently effective against planktonic bacteria in time-kill assays (6-log reduction in bacterial viability within 2 h) and in agar diffusion assays. Bg[Ag] reduced bacterial load in a physiologically relevant ex vivo porcine wound biofilm model; P. aeruginosa (2-log reduction) and S. aureus (3-log reduction). Bg[Ag] also conferred strong effects against P. aeruginosa biofilm virulence, reducing both protease activity and virulence gene expression. Co-culture biofilms appeared more resistant to Bg[Ag], where a selective reduction in S. aureus was observed. Finally, Bg[Ag] was shown to benefit the host response to biofilm infection, directly reducing host tissue cell death. Taken together, the findings provide evidence that Bg[Ag] elicits potent antimicrobial effects against planktonic and single-species biofilms, with beneficial effects on the host tissue response. Further investigations are required to elucidate the specific consequences of BG administration on polymicrobial biofilms, and further explore the effects on host-microbe interactions.}, } @article {pmid30016175, year = {2018}, author = {Cattò, C and Villa, F and Cappitelli, F}, title = {Recent progress in bio-inspired biofilm-resistant polymeric surfaces.}, journal = {Critical reviews in microbiology}, volume = {44}, number = {5}, pages = {633-652}, doi = {10.1080/1040841X.2018.1489369}, pmid = {30016175}, issn = {1549-7828}, mesh = {Bacteria/growth & development ; Bacterial Physiological Phenomena ; Biocompatible Materials/*chemistry/pharmacology ; *Biofilms/growth & development ; Materials Science/*trends ; Polymers/chemistry/pharmacology ; }, abstract = {Any surface of human interest can serve as a substrate for biofilm growth, sometimes with detrimental effects. The social and economic consequences of biofilm-mediated damage to surfaces are significant, the financial impact being estimated to be billions of dollars every year. After describing traditional biocide-based approaches for the remediation of biofilm-affected surfaces, this review deals with more recent developments in material science, focusing on non-toxic, eco-sustainable nature-inspired biomaterials with anti-biofilm properties superior to the conventional biocide-based approaches in terms of addressing the biofilm problem.}, } @article {pmid30015461, year = {2018}, author = {Guan, CP and Luo, HX and Fang, HE and Zhou, XZ}, title = {Global Transcriptome Changes of Biofilm-Forming Staphylococcus epidermidis Responding to Total Alkaloids of Sophorea alopecuroides.}, journal = {Polish journal of microbiology}, volume = {67}, number = {2}, pages = {223-226}, pmid = {30015461}, issn = {1733-1331}, mesh = {Alkaloids/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Computational Biology ; Gene Expression Regulation, Bacterial ; Metabolic Networks and Pathways ; Sophora/*chemistry ; Staphylococcus epidermidis/*drug effects/genetics ; Sulfur/metabolism ; *Transcriptome ; }, abstract = {Transcriptome changes of biofilm-forming Staphylococcus epidermidis response to total alkaloids of Sophorea alopecuroides was observed. Bioinformatic analyses were further used to compare the differential gene expression between control and the treated samples. It was found that 282 genes were differentially expressed, with 92 up-regulated and 190 down-regulated. These involved down-regulation of the sulfur metabolism pathway. It was suggested that inhibitory effects on Staphylococcus epidermidis and its biofilm formation of the total alkaloids of S. alopecuroides was mainly due to the regulation of the sulfur metabolism pathways of S. epidermidis.}, } @article {pmid30015218, year = {2018}, author = {Gondim, BLC and Castellano, LRC and de Castro, RD and Machado, G and Carlo, HL and Valença, AMG and de Carvalho, FG}, title = {Effect of chitosan nanoparticles on the inhibition of Candida spp. biofilm on denture base surface.}, journal = {Archives of oral biology}, volume = {94}, number = {}, pages = {99-107}, doi = {10.1016/j.archoralbio.2018.07.004}, pmid = {30015218}, issn = {1879-1506}, mesh = {Acrylic Resins/chemistry ; Analysis of Variance ; Antifungal Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development ; Candida albicans/drug effects/growth & development ; Chitosan/*antagonists & inhibitors ; Colony Count, Microbial ; Denture Bases/*microbiology ; Hardness ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Particle Size ; Sodium Hypochlorite/pharmacology ; Surface Properties ; }, abstract = {OBJECTIVES: Chitosan nanoparticles (ChNPs) have antifungal effects, however there is a lack of information about the effects of ChNPs against Candida biofilm on denture base surface. This study investigated the ChNPs effect against C. albicans biofilm adhesion and formation, and against Candida spp. biofilm on heat-cured acrylic resin.

DESIGN: The ChNPs were synthetized (3800 μg/mL) and characterized by infra-red spectrophotometry and transmission electron microscopy. The minimum inhibitory/fungicidal concentrations (MIC/MFC) against Candida spp. were determined. The time-kill assay and changes on C. albicans micromorphology were evaluated. The % inhibition of ChNPs on C. albicans biofilm formation and reduction were investigated using 1 min and 8 h exposure. Candida biofilm was developed on resin surfaces and ChNPs were applied every 8 h for 5 days. After, fungal cells were counted (CFU/mL) and the surface roughness (Ra) and vickers microhardness (HV) of resin were analysed. For all experiments, sodium hypochlorite (NaOCl) was used as control. Data were analyzed by ANOVA, Tukey and paired t-tests (α = 0.05).

RESULTS: The MIC80% of ChNPs was 30.1 μg/mL. ChNPs at 4 MIC showed complete inhibition in the time-kill assays. Blastoconidia cells were predominant after ChNPs application. The % inhibition ChNPs on C. albicans was proportional to its concentration, regardless of the exposure time. ChNPs decreased the CFU/mL of Candida spp. and showed lower alteration of HV and Ra values of resin surface compared to NaOCl.

CONCLUSIONS: The ChNPs inhibited C. albicans biofilm, reduced Candida biofilm on resin and caused small changes in roughness and hardness of acrylic resin surface.}, } @article {pmid30015141, year = {2018}, author = {Subramaniyan, SB and Ramani, A and Ganapathy, V and Anbazhagan, V}, title = {Preparation of self-assembled platinum nanoclusters to combat Salmonella typhi infection and inhibit biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {171}, number = {}, pages = {75-84}, doi = {10.1016/j.colsurfb.2018.07.023}, pmid = {30015141}, issn = {1873-4367}, mesh = {Animals ; Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Disease Models, Animal ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Particle Size ; Platinum/chemistry/*pharmacology/*therapeutic use ; Salmonella typhi/*drug effects/growth & development ; Surface Properties ; Typhoid Fever/*drug therapy ; Zebrafish ; }, abstract = {In this work, phytoprotein functionalized platinum nanoparticles (PtNCs) were synthesized using the proteins from fresh green spinach leaves. Transmission electron microscopy showed that PtNCs were spherical shape with size ∼5 nm, which self assembled into spherical platinum nanoclustures (PtNCs) with size within the range of 100-250 nm. The presence of elemental platinum was confirmed by EDX analysis. FTIR studies confirm that the PtNCs were stabilized by the protein. As prepared PtNCs inhibits the growth of the food borne pathogen, Salmonella typhi with minimum inhibitory concentration (MIC) of 12.5 μM. Light microscopy evidenced that the PtNCs can damage the established biofilms. Antibacterial mechanistic study revealed that PtNCs damages the S. typhi membranes, which was confirmed by scanning electron microscopy and further by fluorescence microscopy using acridine orange/propidium iodide dual staining assay. Besides membrane damage, PtNCs also triggered the intracellular ROS-mediated oxidative damage over the antioxidant defense and kills S. typhi. The hemolytic test showed low cytotoxicity of PtNCs at 100 μM (four times higher the MIC). Finally, the therapeutic efficacy of PtNCs was validated in S. typhi infected zebrafish animal model and the obtained results are discussed.}, } @article {pmid30014501, year = {2018}, author = {Torabi Delshad, S and Soltanian, S and Sharifiyazdi, H and Bossier, P}, title = {Effect of quorum quenching bacteria on growth, virulence factors and biofilm formation of Yersinia ruckeri in vitro and an in vivo evaluation of their probiotic effect in rainbow trout.}, journal = {Journal of fish diseases}, volume = {41}, number = {9}, pages = {1429-1438}, doi = {10.1111/jfd.12840}, pmid = {30014501}, issn = {1365-2761}, mesh = {4-Butyrolactone/analogs & derivatives/chemistry/metabolism/pharmacology ; Animals ; Bacillus thuringiensis/physiology ; Biofilms/drug effects ; Citrobacter/physiology ; Culture Media/chemistry/pharmacology ; Fish Diseases/microbiology ; Food ; Oncorhynchus mykiss/*microbiology ; Probiotics/*administration & dosage/*pharmacology/therapeutic use ; *Quorum Sensing ; Virulence Factors ; Yersinia Infections/microbiology ; Yersinia ruckeri/drug effects/*growth & development/*pathogenicity/physiology ; }, abstract = {Five N-acyl homoserine lactone-degrading bacteria (quorum quenching (QQ) strains) were selected to evaluate their impacts on growth, virulence factors and biofilm formation in Yersinia ruckeri in vitro. No difference was observed among the growth pattern of Y. ruckeri in monoculture and coculture with the QQ strains. To investigate the regulation of virulence factors by quorum sensing in Y. ruckeri, cultures were supplemented with 3oxo-C8-HSL. The results indicated that swimming motility and biofilm formation are positively regulated by QS (p < 0.05), whereas caseinase, phospholipase and haemolysin productions are not influenced by 3oxo-C8-HSL (p > 0.05). The QQs were able to decrease swimming motility and biofilm formation in Y. ruckeri. QQ bacteria were supplemented to trout feed at 10[8] CFU/g (for 40 days). Their probiotic effect was verified by Y. ruckeri challenge either by immersion or injection in trout. All strains could significantly increase fish survival with Bacillus thuringiensis and Citrobacter gillenii showing the highest and lowest relative percentage survival (RPS) values (respectively, 85% and 38%). Besides, there was no difference between the RPS values by either immersion or injection challenge expect for B. thuringiensis. The putative involvement of the QQ capacity in the protection against Yersinia is discussed.}, } @article {pmid30013374, year = {2018}, author = {de Alteriis, E and Maselli, V and Falanga, A and Galdiero, S and Di Lella, FM and Gesuele, R and Guida, M and Galdiero, E}, title = {Efficiency of gold nanoparticles coated with the antimicrobial peptide indolicidin against biofilm formation and development of Candida spp. clinical isolates.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {915-925}, pmid = {30013374}, issn = {1178-6973}, abstract = {BACKGROUND: This article examines the use of a novel nano-system, gold nanoparticles coated with indolicidin (AuNPs-indolicidin), against pathogenic Candida albicans biofilms. Candida species cause frequent infections owing to their ability to form biofilms, primarily on implant devices.

MATERIALS AND METHODS: We used an integrated approach, evaluating the effect of AuNPs-indolicidin on prevention and eradication of Candida biofilms formed in multi-well polystyrene plates, with relative gene expression assays. Four biofilm-associated genes (FG1, HWP1, ALS1 and ALS3, and CDR1 and CDR2) involved in efflux pump were analyzed using reverse transcription polymerase chain reaction.

RESULTS: Treatment with the nano-complex significantly inhibits the capacity of C. albicans to form biofilms and impairs preformed mature biofilms. Treatment with AuNPs-indolicidin results in an increase in the kinetics of Rhodamine 6G efflux and a reduction in the expression of biofilm-related genes.

CONCLUSION: These data provide a chance to develop novel therapies against nosocomially acquired refractory C. albicans biofilms.}, } @article {pmid30013272, year = {2018}, author = {Virmani, R and Hasija, Y and Singh, Y}, title = {Effect of Homocysteine on Biofilm Formation by Mycobacteria.}, journal = {Indian journal of microbiology}, volume = {58}, number = {3}, pages = {287-293}, pmid = {30013272}, issn = {0046-8991}, abstract = {Mycobacteria show peculiar aggregated outgrowth like biofilm on the surface of solid or liquid media. Biofilms harbor antibiotic resistant bacteria in a self-produced extracellular matrix that signifies the bacterial fate to sedentary existence. Despite years of research, very little is known about the mechanisms that contribute to biofilm formation. LuxS has been previously known to play a role in biofilm formation in Autoinducer-2 dependent manner. We here show the effect of LuxS product-homocysteine, on the biofilm forming ability of non-tuberculous mycobacteria, Mycobacterium smegmatis and Mycobacterium bovis BCG showing AI-2 independent phenotypic effect of LuxS. Exogenous supplementation of homocysteine in the culture media leads to aberrant cording, pellicle outgrowth, and biofilm formation. Thus, our study contributes to the better understanding of the mechanism of mycobacterial biofilm formation and sheds light on the role of LuxS product homocysteine. In addition, we highlight the contribution of activated methyl cycle in bacterial quorum sensing.}, } @article {pmid30013112, year = {2018}, author = {Fleming, D and Rumbaugh, K}, title = {The Consequences of Biofilm Dispersal on the Host.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {10738}, pmid = {30013112}, issn = {2045-2322}, support = {R21 AI137462/AI/NIAID NIH HHS/United States ; W911NF-13-1-0199//DOD | Army Research Office (ARO)/International ; R01GM116547//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/International ; }, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage ; Biofilms/*drug effects/growth & development ; Disease Models, Animal ; Drug Therapy, Combination/adverse effects/methods ; Glycoside Hydrolases/administration & dosage/*adverse effects ; Humans ; Mice ; Pseudomonas aeruginosa/drug effects/immunology/*pathogenicity ; Sepsis/*chemically induced/immunology/mortality ; Skin/injuries/microbiology ; Wound Infection/*drug therapy/immunology/microbiology ; }, abstract = {Chronic infections are often associated with the presence of a biofilm, a community of microorganisms coexisting within a protective matrix of extracellular polymeric substance. Living within a biofilm can make resident microbes significantly more tolerant to antibiotics in comparison to planktonic, free-floating cells. Thus, agents that can degrade biofilms are being pursued for clinical applications. While biofilm degrading and dispersing agents may represent attractive adjunctive therapies for biofilm-associated chronic infections, very little is known about how the host responds to the sudden dispersal of biofilm cells. In this study, we found that large-scale, in vivo dispersal of motile biofilm bacteria by glycoside hydrolases caused lethal septicemia in the absence of antibiotic therapy in a mouse wound model. However, when administered prudently, biofilm degrading enzymes had the potential to potentiate the efficacy of antibiotics and help resolve biofilm-associated wound infections.}, } @article {pmid30012773, year = {2018}, author = {Blanchard, JD and Elias, V and Cipolla, D and Gonda, I and Bermudez, LE}, title = {Effective Treatment of Mycobacterium avium subsp. hominissuis and Mycobacterium abscessus Species Infections in Macrophages, Biofilm, and Mice by Using Liposomal Ciprofloxacin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {10}, pages = {}, pmid = {30012773}, issn = {1098-6596}, support = {R43 AI106188/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/drug effects ; Female ; Humans ; Liposomes/chemistry ; Macrophages/*microbiology ; Mice ; Mice, Inbred C57BL ; Microbial Sensitivity Tests ; Mycobacterium abscessus/*drug effects/*pathogenicity ; Mycobacterium avium/*drug effects/*pathogenicity ; Polyethylene Glycols ; }, abstract = {Nontuberculous mycobacteria (NTM) affect an increasing number of individuals worldwide. Infection with these organisms is more common in patients with chronic lung conditions, and treatment is challenging. Quinolones, such as ciprofloxacin, have been used to treat patients, but the results have not been encouraging. In this report, we evaluate novel formulations of liposome-encapsulated ciprofloxacin (liposomal ciprofloxacin) in vitro and in vivo Its efficacy against Mycobacterium avium and Mycobacterium abscessus was examined in macrophages, in biofilms, and in vivo using intranasal instillation mouse models. Liposomal ciprofloxacin was significantly more active than free ciprofloxacin against both pathogens in macrophages and biofilms. When evaluated in vivo, treatment with the liposomal ciprofloxacin formulations was associated with significant decreases in the bacterial loads in the lungs of animals infected with M. avium and M. abscessus In summary, topical delivery of liposomal ciprofloxacin in the lung at concentrations greater than those achieved in the serum can be effective in the treatment of NTM, and further evaluation is warranted.}, } @article {pmid30012484, year = {2018}, author = {Wu, Y and Ying, Y and Liu, Y and Zhang, H and Huang, J}, title = {Preparation of chitosan/poly vinyl alcohol films and their inhibition of biofilm formation against Pseudomonas aeruginosa PAO1.}, journal = {International journal of biological macromolecules}, volume = {118}, number = {Pt B}, pages = {2131-2137}, doi = {10.1016/j.ijbiomac.2018.07.061}, pmid = {30012484}, issn = {1879-0003}, mesh = {Biofilms/*drug effects ; Chitosan/chemistry/*pharmacology ; Imaging, Three-Dimensional ; Microbial Viability/drug effects ; Molecular Weight ; Polyvinyl Alcohol/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/*physiology/ultrastructure ; Spectrophotometry, Ultraviolet ; Spectroscopy, Fourier Transform Infrared ; Temperature ; Tensile Strength ; }, abstract = {Poly (vinyl alcohol) (PVA) and chitosan (CH)-based blend films were prepared via a simple mixing and casting method. The films were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV-vis). Mechanical properties, thermogravimetric (TG), derivative thermogravimetric (DTG), and the inhibition of biofilm formation against Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) of CH/PVA films were investigated. The results indicated that CH and PVA in the blend films interacted by physical crosslinks consisting of intermolecular hydrogen bonds and intermolecular hydrogen bonds with compatibility, and were more thermally-stable than that of PVA. CH addition decreased the tensile strength and the light transmittance. CH60:PVA40 film showed notable activity against adhesion and inhibited biofilm formation of P. aeruginosa PAO1, indicating that CH60:PVA40 film could be applied as an antimicrobial and biofilm inhibiting food packaging material.}, } @article {pmid30011379, year = {2018}, author = {Loustau, E and Rols, JL and Leflaive, J and Marcato-Romain, CE and Girbal-Neuhauser, E}, title = {Comparison of extraction methods for the characterization of extracellular polymeric substances from aggregates of three biofilm-forming phototrophic microorganisms.}, journal = {Canadian journal of microbiology}, volume = {64}, number = {11}, pages = {887-899}, doi = {10.1139/cjm-2018-0182}, pmid = {30011379}, issn = {1480-3275}, mesh = {Bacterial Proteins/*analysis/isolation & purification ; Biofilms ; Biomass ; Chlorophyta/*chemistry ; Cyanobacteria/*chemistry ; Diatoms/*chemistry ; *Extracellular Polymeric Substance Matrix ; Fungal Proteins/*analysis/isolation & purification ; Rivers/microbiology ; *Water Microbiology ; }, abstract = {This paper aims to define a robust procedure to extract extracellular polymeric substances (EPS) from aggregates of three benthic phototrophic microorganisms: the cyanobacterium Phormidium autumnale, the diatom Nitzschia palea, and the green alga Uronema confervicolum. This study focuses on the extraction efficiency of polysaccharide and protein EPS by using two physical methods (sonication, cation exchange resin) and three chemical methods (formamide, EDTA, Tween 20) with minimum cell lysis. Cell lysis was evaluated by monitoring chlorophyll a release. The results indicated that sonication or incubation of the algae aggregates with 0.25% Tween 20 induced a high level of cell lysis. A combined extraction approach, with an initial dispersing pretreatment (Ultra-Turrax, 13 500 r·min[-1], 1 min), followed by formamide addition (0.22%) and then incubation with Dowex cation exchange resin (50 g per g of dry biomass), provided the highest amount of extracted EPS (mostly proteins), with low cell lysis. Furthermore, extracted EPS were characterized by size exclusion chromatography, and the obtained fingerprints revealed similar profiles for the three benthic microorganisms with a majority of low molecular weight polymers (400 to 11 300 Da). However, additional EPS of high (>600 000 Da) and intermediate (20 000 to 80 000 Da) molecular sizes were specifically detected in the diatom extracts.}, } @article {pmid30009382, year = {2018}, author = {Ceccarelli, F and Orrù, G and Pilloni, A and Bartosiewicz, I and Perricone, C and Martino, E and Lucchetti, R and Fais, S and Vomero, M and Olivieri, M and di Franco, M and Priori, R and Riccieri, V and Scrivo, R and Shoenfeld, Y and Alessandri, C and Conti, F and Polimeni, A and Valesini, G}, title = {Porphyromonas gingivalis in the tongue biofilm is associated with clinical outcome in rheumatoid arthritis patients.}, journal = {Clinical and experimental immunology}, volume = {194}, number = {2}, pages = {244-252}, pmid = {30009382}, issn = {1365-2249}, mesh = {Adult ; Aged ; Arthritis, Rheumatoid/epidemiology/*immunology ; Bacteroidaceae Infections/epidemiology/*immunology ; Biofilms ; Case-Control Studies ; Cohort Studies ; Disease Progression ; Female ; Humans ; Italy/epidemiology ; Male ; Microbiota/*immunology ; Middle Aged ; Periodontitis/*immunology ; Porphyromonas gingivalis/*physiology ; Prevalence ; Tongue/microbiology/*pathology ; }, abstract = {Several studies have suggested a link between human microbiome and rheumatoid arthritis (RA) development. Porphyromonas gingivalis seems involved in RA initiation and progression, as supported by the high occurrence of periodontitis. In this case-control study, we analysed tongue P. gingivalis presence and quantification in a large healthy and RA cohort. We enrolled 143 RA patients [male/female (M/F) 32/111, mean ± standard deviation (s.d.), age 57·5 ± 19·8 years, mean ± s.d. disease duration 155·9 ± 114·7 months); 36 periodontitis patients (M/F 11/25, mean ± s.d., age 56 ± 9·9 years, mean ± s.d. disease duration 25·5 ± 20·9 months); and 57 patients (M/F 12/45, mean ± s.d., age 61·4 ± 10·9 years, mean ± s.d. disease duration 62·3 ± 66·9 months) with knee osteoarthritis or fibromyalgia. All subjects underwent a standard cytological swab to identify the rate of P. gingivalis/total bacteria by using quantitative real-time polymerase chain reaction. The prevalence of P. gingivalis resulted similarly in RA and periodontitis patients (48·9 versus 52·7%, P = not significant). Moreover, the prevalence of this pathogen was significantly higher in RA and periodontitis patients in comparison with control subjects (P = 0·01 and P = 0·003, respectively). We found a significant correlation between P. gingivalis rate in total bacteria genomes and disease activity score in 28 joints (DAS28) (erythrocyte sedimentation rate) (r = 0·4, P = 0·01). RA patients in remission showed a significantly lower prevalence of P. gingivalis in comparison with non-remission (P = 0·02). We demonstrated a significant association between the percentage of P. gingivalis on the total tongue biofilm and RA disease activity (DAS28), suggesting that the oral cavity microbiological status could play a role in the pathogenic mechanisms of inflammation, leading to more active disease.}, } @article {pmid30009352, year = {2018}, author = {Shafikova, TN and Omelichkina, YV and Enikeev, AG and Boyarkina, SV and Gvildis, DE and Semenov, AA}, title = {Ortho-Phthalic Acid Esters Suppress the Phytopathogen Capability for Biofilm Formation.}, journal = {Doklady biological sciences : proceedings of the Academy of Sciences of the USSR, Biological sciences sections}, volume = {480}, number = {1}, pages = {107-109}, pmid = {30009352}, issn = {1608-3105}, mesh = {Biofilms/*drug effects/*growth & development ; Diethylhexyl Phthalate/*pharmacology ; Micrococcaceae/*physiology ; Pectobacterium carotovorum/*physiology ; }, abstract = {This is the first study demonstrating that ortho-phthalic acid esters, dibutylphthalate (DBP) and di-(2-ethylhexyl)-o-phthalate (DEHP), inhibit the ability to form biofilms of the biotrophic pathogen Clavibacter michiganensis ssp. sepedonicus and Pectobacterium carotovorum ssp. carotovorum necrotroph. Inhibition of biofilm formation depends on the DBP and DEHP concentrations.}, } @article {pmid30008421, year = {2018}, author = {Ngabaza, T and Moeno, S and Patel, M}, title = {Anti-acidogenic and anti-biofilm activity of 5,6,8-trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {149-152}, doi = {10.1016/j.micpath.2018.07.003}, pmid = {30008421}, issn = {1096-1208}, mesh = {Acids/metabolism ; Anti-Bacterial Agents/*chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Dental Caries/microbiology/prevention & control ; Flavones/chemistry/pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/*chemistry/*pharmacology ; Plant Leaves/chemistry ; Sapindaceae/*chemistry ; South Africa ; Streptococcus mutans/drug effects ; }, abstract = {OBJECTIVES: Crude extracts of Dodonaea viscosa var. angustifolia (DVA), has shown to have anticariogenic property. However the compound responsible for this activity has not been identified. The aim of this study was to investigate anti-acidogenic and anti-biofilm activity of a flavone 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one isolated from D. viscosa var. angustifolia (DVA) in cariogenic bacteria Streptococcus mutans.

METHODS: The crude extract from DVA leaves was fractionated into six fractions (F1-F6) using chromatography. The Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentration (MBC) were determined. The effect of the six fractions on biofilm formation and acid production were investigated. The most active fraction (F5) was further fractionated, purified, identified and elucidated using GC-MS and NMR. The anticariogenic property of this purified compound was established. Results were analyzed using Wilcoxon rank-sum test (Mann-Whitney).

RESULTS: The MIC and MBC of the fractions (F1-F6) and crude extract ranged from 0.39 to 12.5 mg/ml. F5 showed the lowest MBC. At 0.2 mg/ml, F5 reduced biofilm formation by 93.3% and reduced acid production in S. mutans. Subfraction F5.1 showed higher antimicrobial activity compared to the crude extract and F5. Purified F5.1 was identified as 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one (TMMC). TMMC inhibited biofilm formation at both 6 h (94% reduction) and 24 h (99% reduction), which was higher compared to the crude extract (87% reduction at 0.78 mg/ml after 6 h). TMMC also exhibited a higher inhibitory effect on acid production compared to the crude extract.

CONCLUSION: Flavone 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one derived from DVA has anti-S. mutans, anti-biofilm and anti-acidogenic activity therefore it has a potential for use in the oral cavity to prevent dental caries.}, } @article {pmid30007730, year = {2018}, author = {de Oliveira Dembogurski, DS and Silva Trentin, D and Boaretto, AG and Rigo, GV and da Silva, RC and Tasca, T and Macedo, AJ and Carollo, CA and Silva, DB}, title = {Brown propolis-metabolomic innovative approach to determine compounds capable of killing Staphylococcus aureus biofilm and Trichomonas vaginalis.}, journal = {Food research international (Ottawa, Ont.)}, volume = {111}, number = {}, pages = {661-673}, doi = {10.1016/j.foodres.2018.05.033}, pmid = {30007730}, issn = {1873-7145}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antioxidants/analysis ; Bees ; Biofilms/*drug effects ; Brazil ; Chromatography, High Pressure Liquid/methods ; Cinnamates/pharmacology ; Dietary Supplements ; Flavonoids ; Metabolomics ; Microbial Sensitivity Tests ; Phenylpropionates/pharmacology ; Propolis/*chemistry/pharmacology ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/*drug effects ; Trichomonas vaginalis/*drug effects ; Trichothecenes/pharmacology ; }, abstract = {Propolis, a resin produced by bees, is widely used in industrial products, including food, cosmetics, supplements, and pharmaceuticals. Extracts (ethanolic and hydroethanolic) and fractions, yielded by accelerated solvent extraction methodology, were obtained from different samples of Brazilian brown propolis (BBP). They were evaluated for antioxidant capacity, antibacterial, antibiofilm, and anti-Trichomonas vaginalis activities. The metabolomics profiling was determined by LC-DAD-MS and an innovative application of statistical analyses (univariate and chemometrics) was applied to correlate chemical compounds with biological activities. Eighty-six compounds were identified, including phenylpropanoic acids, flavonoids, chlorogenic acids, and prenylated phenylpropanoic acids. Propolis-fractions killed about 93% of Staphylococcus aureus in biofilm (at concentration of 125 μg/mL), showed activity against T. vaginalis with MIC at 400 μg/mL and significative antioxidant capacity (IC50 2.32-3.80 μg/mL). Propolis extracts and fractions did not show antibacterial and antibiofilm activities against Pseudomonas aeruginosa. The prenylated phenylpropanoic acids positively correlated with both the antibiofilm (S. aureus) and anti-T. vaginalis activities, such as the metabolites artepillin C, drupanin, and baccharin.}, } @article {pmid30007313, year = {2018}, author = {Hsieh, ML and Hinton, DM and Waters, CM}, title = {VpsR and cyclic di-GMP together drive transcription initiation to activate biofilm formation in Vibrio cholerae.}, journal = {Nucleic acids research}, volume = {46}, number = {17}, pages = {8876-8887}, pmid = {30007313}, issn = {1362-4962}, support = {F30 GM123632/GM/NIGMS NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; MCB1253684//National Science Foundation/International ; }, mesh = {Bacterial Proteins/chemistry/genetics/*physiology ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/physiology ; DNA Footprinting ; DNA, Bacterial/genetics/metabolism ; DNA-Binding Proteins/chemistry/genetics/*physiology ; DNA-Directed RNA Polymerases/metabolism ; Enzyme Activation ; Gene Expression Regulation, Bacterial/*genetics ; Promoter Regions, Genetic/*genetics ; Protein Binding ; Sigma Factor/metabolism ; Structure-Activity Relationship ; *Transcription Initiation, Genetic ; Vibrio cholerae/*genetics/metabolism ; }, abstract = {The small molecule cyclic di-GMP (c-di-GMP) is known to affect bacterial gene expression in myriad ways. In Vibrio cholerae in vivo, the presence of c-di-GMP together with the response regulator VpsR results in transcription from PvpsL, a promoter of biofilm biosynthesis genes. VpsR shares homology with enhancer binding proteins that activate σ54-RNA polymerase (RNAP), but it lacks conserved residues needed to bind to σ54-RNAP and to hydrolyze adenosine triphosphate, and PvpsL transcription does not require σ54 in vivo. Consequently, the mechanism of this activation has not been clear. Using an in vitro transcription system, we demonstrate activation of PvspL in the presence of VpsR, c-di-GMP and σ70-RNAP. c-di-GMP does not significantly change the affinity of VpsR for PvpsL DNA or the DNase I footprint of VpsR on the DNA, and it is not required for VpsR to dimerize. However, DNase I and KMnO4 footprints reveal that the σ70-RNAP/VpsR/c-di-GMP complex on PvpsL adopts a different conformation from that formed by σ70-RNAP alone, with c-di-GMP or with VpsR. Our results suggest that c-di-GMP is required for VpsR to generate the specific protein-DNA architecture needed for activated transcription, a previously unrecognized role for c-di-GMP in gene expression.}, } @article {pmid30006320, year = {2018}, author = {Tan, Y and Cheng, Q and Yang, H and Li, H and Gong, N and Liu, D and Wu, J and Lei, X}, title = {Effects of ALA-PDT on biofilm structure, virulence factor secretion, and QS in Pseudomonas aeruginosa.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {24}, number = {}, pages = {88-94}, doi = {10.1016/j.pdpdt.2018.07.005}, pmid = {30006320}, issn = {1873-1597}, mesh = {Aminolevulinic Acid/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Cell Culture Techniques ; Dose-Response Relationship, Drug ; Microscopy, Confocal ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/drug effects ; Virulence Factors/biosynthesis ; }, abstract = {AIM: To investigate the effects of ALA-PDT on biofilm structure, virulence factor secretion, and quorum sensing (QS) in Pseudomonas aeruginosa.

MATERIALS AND METHODS: We used confocal laser scanning microscopy (CLSM), an XTT assay, scanning electron microscopy (SEM), a virulence factor assay and qRT-PCR in this study.

RESULTS: The XTT assay showed that ALA-PDT significantly inhibited the growth of planktonic P. aeruginosa. CLSM and SEM showed that ALA-PDT destroyed both bacterial and biofilm structures. The virulence factor assay showed that pyocyanin and elastase secretion were significantly inhibited in the ALA-PDT groups. qRT-PCR assays demonstrated that ALA-PDT significantly reduced the mRNA expression of QS-related genes.

CONCLUSION: ALA-PDT kills planktonic and viable biofilm-associated P. aeruginosa cells, destroys biofilm structures, reduces virulence factor secretion and affects QS system gene expression.}, } @article {pmid30006276, year = {2018}, author = {Biswas, N and Samanta, A and Podder, S and Ghosh, CK and Ghosh, J and Das, M and Mallik, AK and Mukhopadhyay, AK}, title = {Phase pure, high hardness, biocompatible calcium silicates with excellent anti-bacterial and biofilm inhibition efficacies for endodontic and orthopaedic applications.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {86}, number = {}, pages = {264-283}, doi = {10.1016/j.jmbbm.2018.06.046}, pmid = {30006276}, issn = {1878-0180}, mesh = {3T3 Cells ; Animals ; Anti-Bacterial Agents/*chemistry/*pharmacology ; Biocompatible Materials/*chemistry/*pharmacology ; Biofilms/*drug effects ; Calcium Compounds/*chemistry/*pharmacology ; Elastic Modulus ; Endodontics ; Hardness ; Materials Testing ; Mice ; Orthopedics ; Silicates/*chemistry/*pharmacology ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Here we report for the very first time the synthesis of 100% phase pure calcium silicate nanoparticles (CSNPs) of the α-wollastonite phase without using any surfactant or peptizer at the lowest ever reported calcination temperature of 850 °C. Further, the phase purity is confirmed by quantitative phase analysis. The nano-network like microstructure of the CSNPs is characterized by FTIR, Raman, XRD, FESEM, TEM, TGA, DSC etc. techniques to derive the structure property correlations. The performance efficacies of the CSNPs against gram-positive e.g., S. pyogenes and S. aureus (NCIM2127) and gram-negative e.g., E. coli (NCIM2065) bacterial strains are studied. The biocompatibility of the CSNPs is established by using the conventional mouse embryonic osteoblast cell line (MC3T3). In addition, the biofilm inhibition efficacies of two varieties of CSNPs e.g., CSNPs(W) and CSNPs(WC) are investigated. Further, the interconnection between ROS e.g., superoxide (O2[.-]) and hydroxyl radical ([.]OH) generation capabilities of CSNPs and their biofilm inhibition efficacies is clearly established for the very first time. Finally, the mechanical responses of the CSNPs at the microstructural length scale are investigated by nanoindentation. The results confirm that the α-wollastonite phases present in CSNPs(W) and CSNPs(WC) possess extraordinarily high nanohardness and Young's moduli values. Therefore, these materials are well suited for orthopaedic and endodontic applications.}, } @article {pmid30003870, year = {2018}, author = {Svenningsen, SL}, title = {Small RNA-Based Regulation of Bacterial Quorum Sensing and Biofilm Formation.}, journal = {Microbiology spectrum}, volume = {6}, number = {4}, pages = {}, doi = {10.1128/microbiolspec.RWR-0017-2018}, pmid = {30003870}, issn = {2165-0497}, mesh = {Bacteria/genetics/*metabolism ; Bacterial Physiological Phenomena ; Bacterial Proteins/physiology ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Quorum Sensing/*physiology ; RNA, Bacterial/*physiology ; Signal Transduction ; Staphylococcus aureus/metabolism ; Transcriptome ; Vibrionaceae/physiology ; }, abstract = {Quorum sensing is a vital property of bacteria that enables community-wide coordination of collective behaviors. A key example of such a behavior is biofilm formation, in which groups of bacteria invest in synthesizing a protective, joint extracellular matrix. Quorum sensing involves the production, release, and subsequent detection of extracellular signaling molecules called autoinducers. The architecture of quorum-sensing signal transduction pathways is highly variable among different species of bacteria, but frequently involves posttranscriptional regulation carried out by small regulatory RNA molecules. This review illustrates the diverse roles small trans-acting regulatory RNAs can play, from constituting a network's core to auxiliary roles in adjusting the rate of autoinducer synthesis, mediating cross talk among different parts of a network, or integrating different regulatory inputs to trigger appropriate changes in gene expression. The emphasis is on describing how the study of small RNA-based regulation in quorum sensing and biofilm formation has uncovered new general properties or expanded our understanding of bacterial riboregulation.}, } @article {pmid30001126, year = {2018}, author = {Lai, CY and Dong, QY and Rittmann, BE and Zhao, HP}, title = {Bioreduction of Antimonate by Anaerobic Methane Oxidation in a Membrane Biofilm Batch Reactor.}, journal = {Environmental science & technology}, volume = {52}, number = {15}, pages = {8693-8700}, doi = {10.1021/acs.est.8b02035}, pmid = {30001126}, issn = {1520-5851}, mesh = {Anaerobiosis ; Archaea ; *Biofilms ; Bioreactors ; *Methane ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; }, abstract = {Employing a special anaerobic membrane biofilm batch reactor (MBBR), we demonstrated antimonate (Sb(V)) reduction using methane (CH4) as the sole electron donor. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman and photoluminescence (PL) spectra identified that Sb2O3 microcrystals were the main reduced products. The Sb(V) reduction rate increased continually over the 111-day experiment, which supports the enrichment of the microorganisms responsible for Sb(V) reduction to Sb(III). Copy numbers of the mcrA gene and archaeal and bacterial 16 S rRNA genes increased in parallel. Clone library and Illumina sequencing of 16S rRNA gene demonstrated that Methanosarcina became the dominant archaea in the biofilm, suggesting that Methanosarcina might play an important role in Sb(V) reduction in the CH4-based MBBR.}, } @article {pmid29998876, year = {2018}, author = {Zhao, J and Cheng, W and He, X and Liu, Y and Li, J and Sun, J and Li, J and Wang, F and Gao, Y}, title = {Association of furanone C-30 with biofilm formation & antibiotic resistance in Pseudomonas aeruginosa.}, journal = {The Indian journal of medical research}, volume = {147}, number = {4}, pages = {400-406}, pmid = {29998876}, issn = {0971-5916}, mesh = {Bacterial Proteins ; *Biofilms ; *Drug Resistance, Microbial ; Furans/*pharmacology ; Humans ; Pseudomonas aeruginosa/*pathogenicity ; Quorum Sensing ; }, abstract = {BACKGROUND & OBJECTIVES: Pseudomonas aeruginosa is an opportunistic pathogen that can cause nosocomial bloodstream infections in humans. This study was aimed to explore the association of furanone C-30 with biofilm formation, quorum sensing (QS) system and antibiotic resistance in P. aeruginosa.

METHODS: An in vitro model of P. aeruginosa bacterial biofilm was established using the standard P. aeruginosa strain (PAO-1). After treatment with 2.5 and 5 μg/ml of furanone C-30, the change of biofilm morphology of PAO-1 was observed, and the expression levels of QS-regulated virulence genes (lasB, rhlA and phzA2), QS receptor genes (lasR, rhlR and pqsR) as well as QS signal molecule synthase genes (lasI, rhlI, pqsE and pqsH) were determined. Besides, the AmpC expression was quantified in planktonic and mature biofilm induced by antibiotics.

RESULTS: Furanone C-30 treatment significantly inhibited biofilm formation in a dose-dependent manner. With the increase of furanone C-30 concentration, the expression levels of lasB, rhlA, phzA2, pqsR, lasI, rhlI pqsE and pqsH significantly decreased in mature biofilm bacteria while the expression levels of lasR and rhlR markedly increased. The AmpC expression was significantly decreased in both planktonic and biofilm bacteria induced by imipenem and ceftazidime.

Furanone C-30 may inhibit biofilm formation and antibiotic resistance in P. aeruginosa through regulating QS genes. The inhibitory effect of furanone C-30 on las system appeared to be stronger than that on rhl system. Further studies need to be done with different strains of P. aeruginosa to confirm our findings.}, } @article {pmid29998558, year = {2018}, author = {Veach, AM and Griffiths, NA}, title = {Testing the light:nutrient hypothesis: Insights into biofilm structure and function using metatranscriptomics.}, journal = {Molecular ecology}, volume = {27}, number = {14}, pages = {2909-2912}, doi = {10.1111/mec.14733}, pmid = {29998558}, issn = {1365-294X}, mesh = {Biofilms ; *Cyanobacteria ; Ecosystem ; Nutrients ; Rivers ; }, abstract = {Aquatic biofilms are hotspots of biogeochemical activity due to concentrated microbial biomass (Battin, Kaplan, Newbold, & Hansen,). However, biofilms are often considered a single entity when their role in biogeochemical transformations is assessed, even though these biofilms harbour functionally diverse microbial communities (Battin, Besemer, Bengtsson, Romani, & Packmann, ; Veach, Stegen, Brown, Dodds, & Jumpponen,). Often overlooked are the biotic interactions among biofilm components that can affect ecosystem-scale processes such as primary production and nutrient cycling. These interactions are likely to be especially important under resource limitation. Light is a primary resource mediating algal photosynthesis and both phototrophic and heterotrophic production due to bacterial reliance on C-rich algal exudates (Cole,). However, current understanding of function-structure linkages in streams has yet to unravel the relative degree of these microbial feedbacks under resource availability gradients. In this issue of Molecular Ecology, Bengtsson, Wagner, Schwab, Urich, and Battin () studied stream biofilm responses to light availability to understand its impact across three domains of life. By integrating biogeochemical rate estimation and metatranscriptomics within a microcosm experiment, they were able to link primary production and nutrient uptake rates to algal and bacterial metabolic processes and specify what taxa contributed to gene expression. Under low light, diatoms and cyanobacteria upregulated photosynthetic machinery and diatom-specific chloroplast rRNA suggesting heightened transcriptional activity under light limitation to maintain phototrophic energy demands. Under high light, heterotrophic bacteria upregulated mRNAs related to phosphorous (P) metabolism while biofilm P uptake increased indicating high bacterial-specific P demand when algal biomass was high. Together, these results indicate that biogeochemical function is mediated by complex microbial interactions across trophic levels.}, } @article {pmid29997746, year = {2018}, author = {Goudarzi, M and Mobarez, AM and Najar-Peerayeh, S and Mirzaee, M}, title = {Prevalence of biofilm formation and vancomycin-resistant genes among Enterococcus faecium isolated from clinical and environmental specimens in Lorestan hospitals.}, journal = {Iranian journal of microbiology}, volume = {10}, number = {2}, pages = {74-81}, pmid = {29997746}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The antibiotic resistance among Enterococcus faecium strains has increased worldwide. Additionally, biofilm-forming isolates of E. faecium play an important role in human infections. This study was conducted to investigate the prevalence of virulence and antibiotic resistance genes between biofilm-producing and non-biofilm-producing E. faecium strains.

MATERIALS AND METHODS: In this study, 228 E. faecium isolates from clinical and environmental specimens were obtained from different wards of hospitals in Lorestan province (Iran). Then, the pattern of antibiotic resistance and minimum inhibitory concentration (MIC) against β-lactams, glycopeptides, aminoglycosides and other common antibiotics was investigated using disk diffusion and agar dilution methods. Biofilm formation was investigated using polystyrene microtiter plates. PCR assay was conducted for antibiotic resistance and biofilm related genes. Pulse field gel electrophoresis (PFGE) was used to determine the clonal spread of isolates.

RESULTS: Most of isolates (78%) were resistant to penicillin, but all were susceptible to linezolid and tigecycline. The biofilm-producing isolates were more resistant to β-lactams, glycopeptides and aminoglycosides compared to non-biofilm-producing strains. In biofilm-producing isolates, pilA, pilB, efaAfm and esp were the dominant virulence genes and vanA and pbp5 genes were the dominant resistant genes. PFGE analysis exhibited a similar pattern between the clinical and environmental isolates, suggesting the presence of a common origin of the infection by E. faecium.

CONCLUSION: The results of the antibiotic resistance, biofilm assay, and PFGE analysis suggest that there is a common clone of persistent and biofilm-producing strains of E. faecium, which could rapidly disseminate in patients and the environment.}, } @article {pmid29997606, year = {2018}, author = {Miyaue, S and Suzuki, E and Komiyama, Y and Kondo, Y and Morikawa, M and Maeda, S}, title = {Bacterial Memory of Persisters: Bacterial Persister Cells Can Retain Their Phenotype for Days or Weeks After Withdrawal From Colony-Biofilm Culture.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1396}, pmid = {29997606}, issn = {1664-302X}, abstract = {Persister cells, or persisters, are a specific subpopulation of bacterial cells that have acquired temporary antibiotic-resistant phenotypes. In this study, we showed that Escherichia coli produces many more persister cells in colony-biofilm culture than in the usual liquid culture and that these persisters can be maintained in higher numbers than those from liquid culture for up to 4 weeks at 37°C in a fresh, nutrient-rich, antibiotic-containing medium, even after complete withdrawal from the colony-biofilm culture. This suggests the presence of a long-retention effect, or "memory effect", in the persister cell state of E. coli cells. We also discovered that such increases in persisters during colony-biofilm culture and their memory effects are common, to a greater or lesser degree, in other bacterial species. This is true not only for gram-negative bacteria (Acinetobacter and Salmonella) but also for gram-positive bacteria (Staphylococcus and Bacillus). This is the first report to suggest the presence of a common memory mechanism for the persister cell state, which is inscribed during colony-biofilm culture, in a wide variety of bacteria.}, } @article {pmid29997584, year = {2018}, author = {Somorin, YM and Vollmerhausen, T and Waters, N and Pritchard, L and Abram, F and Brennan, F and O'Byrne, C}, title = {Absence of Curli in Soil-Persistent Escherichia coli Is Mediated by a C-di-GMP Signaling Defect and Suggests Evidence of Biofilm-Independent Niche Specialization.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1340}, pmid = {29997584}, issn = {1664-302X}, abstract = {Escherichia coli is commonly viewed as a gastrointestinal commensal or pathogen although an increasing body of evidence suggests that it can persist in non-host environments as well. Curli are a major component of biofilm in many enteric bacteria including E. coli and are important for adherence to different biotic and abiotic surfaces. In this study we investigated curli production in a unique collection of soil-persistent E. coli isolates and examined the role of curli formation in environmental persistence. Although most soil-persistent E. coli were curli-positive, 10% of isolates were curli-negative (17 out of 170). Curli-producing E. coli (COB583, COB585, and BW25113) displayed significantly more attachment to quartz sand than the curli-negative strains. Long-term soil survival experiments indicated that curli production was not required for long-term survival in live soil (over 110 days), as a curli-negative mutant BW25113ΔcsgB had similar survival compared to wild type BW25113. Mutations in two genes associated with c-di-GMP metabolism, dgcE and pdeR, correlated with loss of curli in eight soil-persistent strains, although this did not significantly impair their survival in soil compared to curli-positive strains. Overall, the data indicate that curli-deficient and biofilm-defective strains, that also have a defect in attachment to quartz sand, are able to reside in soil for long periods of time thus pointing to the possibility that niches may exist in the soil that can support long-term survival independently of biofilm formation.}, } @article {pmid29997579, year = {2018}, author = {Hu, X and Huang, YY and Wang, Y and Wang, X and Hamblin, MR}, title = {Antimicrobial Photodynamic Therapy to Control Clinically Relevant Biofilm Infections.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1299}, pmid = {29997579}, issn = {1664-302X}, abstract = {Biofilm describes a microbially-derived sessile community in which microbial cells are firmly attached to the substratum and embedded in extracellular polymeric matrix. Microbial biofilms account for up to 80% of all bacterial and fungal infections in humans. Biofilm-associated pathogens are particularly resistant to antibiotic treatment, and thus novel antibiofilm approaches needed to be developed. Antimicrobial Photodynamic therapy (aPDT) had been recently proposed to combat clinically relevant biofilms such as dental biofilms, ventilator associated pneumonia, chronic wound infections, oral candidiasis, and chronic rhinosinusitis. aPDT uses non-toxic dyes called photosensitizers (PS), which can be excited by harmless visible light to produce reactive oxygen species (ROS). aPDT is a multi-stage process including topical PS administration, light irradiation, and interaction of the excited state with ambient oxygen. Numerous in vitro and in vivo aPDT studies have demonstrated biofilm-eradication or substantial reduction. ROS are produced upon photo-activation and attack adjacent targets, including proteins, lipids, and nucleic acids present within the biofilm matrix, on the cell surface and inside the microbial cells. Damage to non-specific targets leads to the destruction of both planktonic cells and biofilms. The review aims to summarize the progress of aPDT in destroying biofilms and the mechanisms mediated by ROS. Finally, a brief section provides suggestions for future research.}, } @article {pmid29997121, year = {2018}, author = {Kean, R and Delaney, C and Sherry, L and Borman, A and Johnson, EM and Richardson, MD and Rautemaa-Richardson, R and Williams, C and Ramage, G}, title = {Transcriptome Assembly and Profiling of Candida auris Reveals Novel Insights into Biofilm-Mediated Resistance.}, journal = {mSphere}, volume = {3}, number = {4}, pages = {}, pmid = {29997121}, issn = {2379-5042}, support = {BB/P504567/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Biofilms/*drug effects/*growth & development ; Biological Transport, Active ; Candida/*drug effects/genetics/*physiology ; *Drug Resistance, Fungal ; *Gene Expression Profiling ; Membrane Transport Proteins/genetics/metabolism ; }, abstract = {Candida auris has emerged as a significant global nosocomial pathogen. This is primarily due to its antifungal resistance profile but also its capacity to form adherent biofilm communities on a range of clinically important substrates. While we have a comprehensive understanding of how other Candida species resist and respond to antifungal challenge within the sessile phenotype, our current understanding of C. auris biofilm-mediated resistance is lacking. In this study, we are the first to perform transcriptomic analysis of temporally developing C. auris biofilms, which were shown to exhibit phase- and antifungal class-dependent resistance profiles. A de novo transcriptome assembly was performed, where sequenced sample reads were assembled into an ~11.5-Mb transcriptome consisting of 5,848 genes. Differential expression (DE) analysis demonstrated that 791 and 464 genes were upregulated in biofilm formation and planktonic cells, respectively, with a minimum 2-fold change. Adhesin-related glycosylphosphatidylinositol (GPI)-anchored cell wall genes were upregulated at all time points of biofilm formation. As the biofilm developed into intermediate and mature stages, a number of genes encoding efflux pumps were upregulated, including ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporters. When we assessed efflux pump activity biochemically, biofilm efflux was greater than that of planktonic cells at 12 and 24 h. When these were inhibited, fluconazole sensitivity was enhanced 4- to 16-fold. This study demonstrates the importance of efflux-mediated resistance within complex C. auris communities and may explain the resistance of C. auris to a range of antimicrobial agents within the hospital environment.IMPORTANCE Fungal infections represent an important cause of human morbidity and mortality, particularly if the fungi adhere to and grow on both biological and inanimate surfaces as communities of cells (biofilms). Recently, a previously unrecognized yeast, Candida auris, has emerged globally that has led to widespread concern due to the difficulty in treating it with existing antifungal agents. Alarmingly, it is also able to grow as a biofilm that is highly resistant to antifungal agents, yet we are unclear about how it does this. Here, we used a molecular approach to investigate the genes that are important in causing the cells to be resistant within the biofilm. The work provides significant insights into the importance of efflux pumps, which actively pump out toxic antifungal drugs and therefore enhance fungal survival within a variety of harsh environments.}, } @article {pmid29995593, year = {2020}, author = {Gou, Y and Yang, J and Fang, F and Guo, J and Ma, H}, title = {Feasibility of using a novel algal-bacterial biofilm reactor for efficient domestic wastewater treatment.}, journal = {Environmental technology}, volume = {41}, number = {4}, pages = {400-410}, doi = {10.1080/09593330.2018.1499812}, pmid = {29995593}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Chlorella ; Feasibility Studies ; Nitrogen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Current algal-bacterial consortia require high hydraulic retention times (HRTs, 2-10 days) to efficiently remove pollutants from domestic wastewaters. A novel algal-bacterial biofilm reactor was developed for a much lower HRT. The results showed that an HRT of 12 h ensured 90% removal of organic matter and ammonium, and phosphate removal was approximately 30%. Decreasing the HRT to 8 h significantly deteriorated the reactor's pollutant removal efficiencies and increasing the HRT to 24 h did not improve these efficiencies. Illumination, which was light source for algae, was provided by a LED light. Activity tests showed that organic matter and ammonium removal rates resulting from illumination were 70% and 50%, respectively, of the rates when dissolved oxygen concentration was maintained at 2 mg/L. Chemical oxygen demand (COD) removal rates resulted from illumination and aeration were 18.63 and 25.38 mg COD/L.h, respectively. The phosphate removal rate was 0.26 and 0.43 mg/L.h when illumination and aeration were applied, respectively. The ammonium removal rates were approximately 10,390 and 5000 mg [Formula: see text] when the reactor was aerated or illuminated, respectively. These two rates were significantly higher than reported nitrification rates. Moreover, the percentage of Oscillatoria sp. increased from below 10% to over 90% under the applied organic load and temperature, while the percentage of fast growing algae, Chlorella, chroococcus sp and Scenedesmus sp., decreased from over 90% to below 10%. These results showed that an algal-bacterial biofilm reactor with a low reactor footprint was developed.}, } @article {pmid29995389, year = {2018}, author = {Shogren, AJ and Tank, JL and Egan, SP and August, O and Rosi, EJ and Hanrahan, BR and Renshaw, MA and Gantz, CA and Bolster, D}, title = {Water Flow and Biofilm Cover Influence Environmental DNA Detection in Recirculating Streams.}, journal = {Environmental science & technology}, volume = {52}, number = {15}, pages = {8530-8537}, doi = {10.1021/acs.est.8b01822}, pmid = {29995389}, issn = {1520-5851}, mesh = {Animals ; Biofilms ; DNA ; *Ecosystem ; Fishes ; *Rivers ; }, abstract = {The increasing use of environmental DNA (eDNA) for determination of species presence in aquatic ecosystems is an invaluable technique for both ecology as a field and for the management of aquatic ecosystems. We examined the degradation dynamics of fish eDNA using an experimental array of recirculating streams, also using a "nested" primer assay to estimate degradation among eDNA fragment sizes. We introduced eDNA into streams with a range of water velocities (0.1-0.8 m s[-1]) and substrate biofilm coverage (0-100%) and monitored eDNA concentrations over time (∼10 d) to assess how biophysical conditions influence eDNA persistence. We found that the presence of biofilm significantly increased initial decay rates relative to previous studies conducted in nonflowing microcosms, suggesting important differences in detection and persistence in lentic vs lotic systems. Lastly, by using a nested primer assay that targeted different size eDNA fragments, we found that fragment size altered both the estimated rate constant coefficients, as well as eDNA detectability over time. Larger fragments (>600 bp) were quickly degraded, while shorter fragments (<100 bp) remained detectable for the entirety of the experiment. When using eDNA as a stream monitoring tool, understanding environmental factors controlling eDNA degradation will be critical for optimizing eDNA sampling strategies.}, } @article {pmid29993359, year = {2018}, author = {Topa, SH and Subramoni, S and Palombo, EA and Kingshott, P and Rice, SA and Blackall, LL}, title = {Cinnamaldehyde disrupts biofilm formation and swarming motility of Pseudomonas aeruginosa.}, journal = {Microbiology (Reading, England)}, volume = {164}, number = {9}, pages = {1087-1097}, doi = {10.1099/mic.0.000692}, pmid = {29993359}, issn = {1465-2080}, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Locomotion/*drug effects ; Membrane Potentials/drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/physiology ; Secondary Metabolism/drug effects ; }, abstract = {Bacterial biofilms can cause serious health care complications associated with increased morbidity and mortality. There is an urge to discover and develop new biofilm inhibitors from natural products or by modifying natural compounds or understanding the modes of action of existing compounds. Cinnamaldehyde (CAD), one of the major components of cinnamon oil, has been demonstrated to act as an antimicrobial agent against a number of Gram-negative and Gram-positive pathogens, including Pseudomonas aeruginosa, Helicobacter pylori and Listeria monocytogenes. Despite the mechanism of action of CAD against the model organism P. aeruginosa being undefined, based on its antimicrobial properties, we hypothesized that it may disrupt preformed biofilms of P. aeruginosa. The minimum inhibitory concentration (MIC) of CAD for planktonic P. aeruginosa was determined to be 11.8 mM. Membrane depolarization assays demonstrated disruption of the transmembrane potential of P. aeruginosa. CAD at 5.9 mM (0.5 MIC) disrupted preformed biofilms by 75.6 % and 3 mM CAD (0.25 MIC) reduced the intracellular concentrations of the secondary messenger, bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which controls P. aeruginosa biofilm formation. The swarming motility of P. aeruginosa was also reduced by CAD in a concentration-dependent manner. Collectively, these findings show that sub-MICs of CAD can disrupt biofilms and other surface colonization phenotypes through the modulation of intracellular signalling processes.}, } @article {pmid29992882, year = {2018}, author = {Srivastava, V and Singla, RK and Dubey, AK}, title = {Inhibition of Biofilm and Virulence Factors of Candida albicans by Partially Purified Secondary Metabolites of Streptomyces chrestomyceticus Strain ADP4.}, journal = {Current topics in medicinal chemistry}, volume = {18}, number = {11}, pages = {925-945}, doi = {10.2174/1568026618666180711154110}, pmid = {29992882}, issn = {1873-4294}, mesh = {Alkaloids/chemistry/metabolism/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/*pathogenicity ; Flavonoids/chemistry/metabolism/pharmacology ; Polyphenols/chemistry/metabolism/pharmacology ; *Secondary Metabolism ; Streptomyces/*chemistry/*metabolism ; Terpenes/chemistry/metabolism/pharmacology ; Triterpenes/chemistry/metabolism/pharmacology ; Virulence Factors/*antagonists & inhibitors ; }, abstract = {BACKGROUND: Despite several advancements in antifungal drug discovery, fungal diseases like Invasive Candidiasis (IC) still remain associated with high rates of morbidity and mortality worldwide. Thus there is an enormous need for anti-Candida drugs.

OBJECTIVE: The main objectives of the work included: 1. To investigate therapeutically significant classes of secondary metabolites produced by S. chrestomyceticus strain ADP4. 2. To investigate and analyze inhibition of significant virulence attributes of C. albicans, such as, biofilm and secretory hydrolytic enzymes by ADP4 secondary metabolites. 3. Mechanistic analysis of probable compounds for their site of action on Secretary Aspartyl Proteinase 3 (Sap3).

METHODS: Metabolite extract-SDB (MESDB) of S. chrestomyceticus strain ADP4 was fractionated on silica gel column chromatography. Fractions were analyzed for anti-Candida activity by disc diffusion assay. Active fractions were further purified by differential solvent treatment. MIC90 values were determined by broth dilution method. MFC was based on counting viable cells. Inhibition of yeast to hyphae transition and that of production of hydrolytic enzymes were estimated by plate assays. GC-MS of MESDB and Partially Purified Metabolite preparations (PPMs) was done. GRIP docking studies with Sap 3 of C. albicans was done using VLife MDS 4.6 software.

RESULTS: Chemical profiling showed that ADP4 secondary metabolites contained alkaloids, flavonoids, polyphenols, terpenoids and triterpenes. The MESDB and the PPMs showed low or no cytotoxicity but were able to effectively contain virulence attributes of Candida pathogen. Docking studies revealed that some of the probable compounds have affinity for aspartic acid residue in Sap3 enzyme of C. albicans.

CONCLUSION: Secondary metabolite of strain ADP4 included important classes of therapeutically important compounds. Their anti-Candida activity was mediated by inhibition of critical virulence factors of the pathogen.}, } @article {pmid29991767, year = {2018}, author = {Raymond, BBA and Jenkins, C and Turnbull, L and Whitchurch, CB and Djordjevic, SP}, title = {Extracellular DNA release from the genome-reduced pathogen Mycoplasma hyopneumoniae is essential for biofilm formation on abiotic surfaces.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {10373}, pmid = {29991767}, issn = {2045-2322}, mesh = {Animals ; Biofilms/*growth & development ; DNA/*metabolism ; Deoxyribonucleases/pharmacology ; Epithelial Cells/microbiology ; Genome, Microbial/*genetics ; Lung/microbiology ; Mycoplasma hyopneumoniae/cytology/*genetics/physiology ; Surface Properties ; Swine ; }, abstract = {Mycoplasma hyopneumoniae is an economically devastating, globally disseminated pathogen that can maintain a chronic infectious state within its host, swine. Here, we depict the events underpinning M. hyopneumoniae biofilm formation on an abiotic surface and demonstrate for the first time, biofilms forming on porcine epithelial cell monolayers and in the lungs of pigs, experimentally infected with M. hyopneumoniae. Nuclease treatment prevents biofilms forming on glass but not on porcine epithelial cells indicating that extracellular DNA (eDNA), which localises at the base of biofilms, is critical in the formation of these structures on abiotic surfaces. Subpopulations of M. hyopneumoniae cells, denoted by their ability to take up the dye TOTO-1 and release eDNA, were identified. A visually distinct sub-population of pleomorphic cells, that we refer to here as large cell variants (LCVs), rapidly transition from phase dark to translucent "ghost" cells. The translucent cells accumulate the membrane-impermeable dye TOTO-1, forming readily discernible membrane breaches immediately prior to lysis and the possible release of eDNA and other intracellular content (public goods) into the extracellular environment. Our novel observations expand knowledge of the lifestyles adopted by this wall-less, genome-reduced pathogen and provide further insights to its survival within farm environments and swine.}, } @article {pmid29991582, year = {2018}, author = {Giacalone, D and Smith, TJ and Collins, AJ and Sondermann, H and Koziol, LJ and O'Toole, GA}, title = {Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor.}, journal = {mBio}, volume = {9}, number = {4}, pages = {}, pmid = {29991582}, issn = {2150-7511}, support = {P20 RR030360/RR/NCRR NIH HHS/United States ; R01 GM123609/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/*metabolism ; Phosphorus-Oxygen Lyases/*metabolism ; Pseudomonas fluorescens/*growth & development/*metabolism ; Signal Transduction ; }, abstract = {The bacterial intracellular second messenger, cyclic dimeric GMP (c-di-GMP), regulates biofilm formation for many bacteria. The binding of c-di-GMP by the inner membrane protein LapD controls biofilm formation, and the LapD receptor is central to a complex network of c-di-GMP-mediated biofilm formation. In this study, we examine how c-di-GMP signaling specificity by a diguanylate cyclase (DGC), GcbC, is achieved via interactions with the LapD receptor and by small ligand sensing via GcbC's calcium channel chemotaxis (CACHE) domain. We provide evidence that biofilm formation is stimulated by the environmentally relevant organic acid citrate (and a related compound, isocitrate) in a GcbC-dependent manner through enhanced GcbC-LapD interaction, which results in increased LapA localization to the cell surface. Furthermore, GcbC shows little ability to synthesize c-di-GMP in isolation. However, when LapD is present, GcbC activity is significantly enhanced (~8-fold), indicating that engaging the LapD receptor stimulates the activity of this DGC; citrate-enhanced GcbC-LapD interaction further stimulates c-di-GMP synthesis. We propose that the I-site of GcbC serves two roles beyond allosteric control of this enzyme: promoting GcbC-LapD interaction and stabilizing the active conformation of GcbC in the GcbC-LapD complex. Finally, given that LapD can interact with a dozen different DGCs of Pseudomonas fluorescens, many of which have ligand-binding domains, the ligand-mediated enhanced signaling via LapD-GcbC interaction described here is likely a conserved mechanism of signaling in this network. Consistent with this idea, we identify a second example of ligand-mediated enhancement of DGC-LapD interaction that promotes biofilm formation.IMPORTANCE In many bacteria, dozens of enzymes produce the dinucleotide signal c-di-GMP; however, it is unclear how undesired cross talk is mitigated in the context of this soluble signal and how c-di-GMP signaling is regulated by environmental inputs. We demonstrate that GcbC, a DGC, shows little ability to synthesize c-di-GMP in the absence of its cognate receptor LapD; GcbC-LapD interaction enhances c-di-GMP synthesis by GcbC, likely mediated by the I-site of GcbC. We further show evidence for a ligand-mediated mechanism of signaling specificity via increased physical interaction of a DGC with its cognate receptor. We envision a scenario wherein a "cloud" of weakly active DGCs can increase their activity by specific interaction with their receptor in response to appropriate environmental signals, concomitantly boosting c-di-GMP production, ligand-specific signaling, and biofilm formation.}, } @article {pmid29990766, year = {2018}, author = {Zhang, X and Yuan, H and Jiang, Z and Lin, D and Zhang, X}, title = {Impact of surface tension of wastewater on biofilm formation of microalgae Chlorella sp.}, journal = {Bioresource technology}, volume = {266}, number = {}, pages = {498-506}, doi = {10.1016/j.biortech.2018.06.082}, pmid = {29990766}, issn = {1873-2976}, mesh = {*Biofilms ; *Chlorella ; Microalgae ; Surface Tension ; *Wastewater ; }, abstract = {The organic matter and surfactants in wastewater may cause variations in the surface tension of wastewater (STW) ranging between ∼40 and ∼70 mJ·m[-2]. This study focused on the influence of STW on microalgae biofilm formation. A theoretical analysis was first conducted, and then microalgae biofilm formation on hydrophilic and hydrophobic substrata in liquid and real wastewater with different surface tensions was studied. The results demonstrated that STW affected microalgae biofilm formation remarkably. When the surface tension of liquid medium (γ[lv]) was approximately equal to the average value of surface free energy of microalgae and substrata, biofilm formation reached the minimum. Microalgae biofilm formation on a hydrophilic surface first decreased (from ∼2200 to ∼1500 cells/mm[2]) and then increased (from ∼1500 to 3100 cells/mm[2]) with the decrease in γ[lv] (from ∼70 to ∼40 mJ·m[-2]), whereas biofilm on a hydrophobic surface continued to decrease (from ∼2500 to 1000 cells/mm[2]).}, } @article {pmid29990546, year = {2018}, author = {Caldara, M and Marmiroli, N}, title = {Tricyclic antidepressants inhibit Candida albicans growth and biofilm formation.}, journal = {International journal of antimicrobial agents}, volume = {52}, number = {4}, pages = {500-505}, doi = {10.1016/j.ijantimicag.2018.06.023}, pmid = {29990546}, issn = {1872-7913}, mesh = {Amphotericin B/pharmacology ; Antidepressive Agents, Tricyclic/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/drug effects/genetics/growth & development/metabolism ; Candida albicans/*drug effects/genetics/growth & development/metabolism ; Candida glabrata/drug effects/genetics/growth & development/metabolism ; Doxepin/*pharmacology ; Drug Repositioning ; Drug Synergism ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Humans ; Hyphae/drug effects/genetics/growth & development/metabolism ; Imipramine/*pharmacology ; Inactivation, Metabolic ; Microsomes, Liver/metabolism ; Nortriptyline/*pharmacology ; Plankton/drug effects/genetics/growth & development/metabolism ; }, abstract = {Candida albicans is a commensal yeast of the human body, able to form biofilms on solid surfaces such as implanted medical devices, and contributes to nosocomial infections. Biofilms have the capacity to resist higher levels of antifungals compared with planktonic cells, and can develop tolerance to commonly used treatments. The necessity to overcome acquired drug resistance and identify new active molecules with low toxicity is a significant problem. It has been reported that some antidepressants have antibacterial properties, but little is known regarding the effect of these drugs on fungi. This study demonstrated the capacity of three tricyclic antidepressants (doxepin, imipramine and nortriptyline) to inhibit the growth and biofilm formation of Candida spp. The antimicrobial potential of the drugs was assessed by studying gene expression, hyphae formation, biofilm growth and maturation. Their negative impact on the growth of C. albicans and other Candida spp. is shown in vitro and with the hepatic S9 system, which is preliminary to any in-vivo test. This study found that the antidepressants considered can inhibit not only hyphae and biofilm formation, but also kill cells in a mature biofilm. Moreover, cell lysis by nortriptyline was observed, along with its synergistic activity with amphotericin B. These findings suggest that tricyclic antidepressants, particularly nortriptyline, should be studied further in drug repositioning programmes to assess their antimycotic capacity in full.}, } @article {pmid29989414, year = {2018}, author = {Bao, J and Liu, N and Zhu, L and Xu, Q and Huang, H and Jiang, L}, title = {Programming a Biofilm-Mediated Multienzyme-Assembly-Cascade System for the Biocatalytic Production of Glucosamine from Chitin.}, journal = {Journal of agricultural and food chemistry}, volume = {66}, number = {30}, pages = {8061-8068}, doi = {10.1021/acs.jafc.8b02142}, pmid = {29989414}, issn = {1520-5118}, mesh = {Archaeal Proteins/chemistry/genetics/*metabolism ; Biocatalysis ; Biofilms ; Chitin/*metabolism ; Enzyme Stability ; Glucosamine/*metabolism ; Hydrogen-Ion Concentration ; Temperature ; Thermococcus/*enzymology ; }, abstract = {Chitin is used as an essential raw material for the production of glucosamine (GlcN). In this study, we adopted three key enzymes, isolated from Thermococcus kodakaraensis KOD1, that catalyze the sequential conversion of α-chitin into GlcN and developed a multienzyme-assembly-cascade (MAC) system immobilized in a bacterial biofilm, which enabled a multistep one-pot reaction. Specifically, the SpyTag-SpyCatcher and SnoopTag-SnoopCatcher pairs provided covalent and specific binding force to fix enzymes to the biofilm one by one and assemble close enzyme cascades. The MAC system showed great catalytic activity, converting 79.02 ± 3.61% of α-chitin into GlcN with little byproducts, which was 2.09 times that of GlcN catalyzed by a mixture of pure enzymes. The system also exhibited good temperature and pH stability. Notably, 90% of enzyme activity was retained after 6 rounds of reuse, and appreciable activity remained after 17 rounds.}, } @article {pmid29989280, year = {2018}, author = {Wang, Y and Yi, L and Zhang, J and Sun, L and Wen, W and Zhang, C and Wang, S}, title = {Functional analysis of superoxide dismutase of Salmonella typhimurium in serum resistance and biofilm formation.}, journal = {Journal of applied microbiology}, volume = {125}, number = {5}, pages = {1526-1533}, doi = {10.1111/jam.14044}, pmid = {29989280}, issn = {1365-2672}, support = {2018YFD0500100//National Key Research and Development Program of China/ ; 31772761//National Natural Science Foundation of China/ ; 31540095//National Natural Science Foundation of China/ ; 182300410047//Science and Technology Development Project of Henan Province/ ; 162300410067//Science and Technology Development Project of Henan Province/ ; //China Scholarship Council (CSC)/ ; }, mesh = {Bacterial Adhesion/genetics ; Bacterial Proteins/genetics/*physiology ; Biofilms/growth & development ; HeLa Cells ; Humans ; Salmonella typhimurium/*genetics/growth & development/pathogenicity ; Stress, Physiological ; Superoxide Dismutase/genetics/*physiology ; Virulence/genetics ; }, abstract = {AIMS: Further investigations of the novel biological functions of SodA in Salmonella enterica serovar typhimurium (Salm. typhimurium).

METHODS AND RESULTS: A deletion mutant of sodA in Salm. typhimurium was constructed and its biological characteristics were analysed. More specifically, the roles of superoxide dismutase (SOD) in resistance to environmental stresses and serum, biofilm formation, epithelial cell adherence and invasion were investigated. Inactivation of sodA gene resulted in a slightly reduced growth rate, low SOD activity and increased susceptibility to reactive oxygen species and chicken serum. However, SodA was not involved in the motility of Salm. typhimurium. In addition, the sodA mutant exhibited a decreased capacity to form biofilm as well as to adhere and invade to HeLa cells, compared to the wild-type and complemented strains.

CONCLUSIONS: Salmonella typhimurium SOD appears to play an important role in resistance to serum and oxidative stress, biofilm formation, adherence to and invasion of epithelial cells.

This study illustrates the novel roles of SodA in serum resistance and biofilm formation in Salm. typhimurium, which may provide a candidate for the biofilm eradication and prevention of infections.}, } @article {pmid29988395, year = {2018}, author = {Li, B and Huang, Q and Cui, A and Liu, X and Hou, B and Zhang, L and Liu, M and Meng, X and Li, S}, title = {Overexpression of Outer Membrane Protein X (OmpX) Compensates for the Effect of TolC Inactivation on Biofilm Formation and Curli Production in Extraintestinal Pathogenic Escherichia coli (ExPEC).}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {208}, pmid = {29988395}, issn = {2235-2988}, mesh = {Bacterial Outer Membrane Proteins/genetics/*metabolism ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Escherichia coli Proteins/genetics/*metabolism ; Extraintestinal Pathogenic Escherichia coli/genetics/*growth & development ; Gene Deletion ; *Gene Expression ; Gene Expression Profiling ; Hydrolases/genetics/*metabolism ; Membrane Transport Proteins/*deficiency ; Real-Time Polymerase Chain Reaction ; }, abstract = {Our previous study showed that the inactivation of the efflux pump TolC could abolish biofilm formation and curli production of extraintestinal pathogenic Escherichia coli (ExPEC) strain PPECC42 under hyper-osmotic conditions. In this study we investigated the role of OmpX in biofilm formation and curli production of ExPEC PPECC42. Our data showed that OmpX disruption or overexpression didn't significantly affect the biofilm formation and curli production of the wild-type strain. However, in the tolC-deleted mutant, overexpressing OmpX suppressed the effect of TolC inactivation on ExPEC biofilm formation and curli production under hyper-osmotic growth conditions. Real-time qRT-PCR confirmed that OmpX overexpression affected curli production by regulating the transcription of the curli biosynthesis-related genes in the ΔtolC strain. Our findings suggest that OmpX is involved in biofilm formation and curli production.}, } @article {pmid29987645, year = {2018}, author = {Ricciardi, BF and Muthukrishnan, G and Masters, E and Ninomiya, M and Lee, CC and Schwarz, EM}, title = {Staphylococcus aureus Evasion of Host Immunity in the Setting of Prosthetic Joint Infection: Biofilm and Beyond.}, journal = {Current reviews in musculoskeletal medicine}, volume = {11}, number = {3}, pages = {389-400}, pmid = {29987645}, issn = {1935-973X}, support = {P50 AR072000/AR/NIAMS NIH HHS/United States ; P30 AR069655//National Institutes of Health/ ; P50 AR07200//National Institutes of Health/ ; }, abstract = {PURPOSE OF REVIEW: The incidence of complications from prosthetic joint infection (PJI) is increasing, and treatment failure remains high. We review the current literature with a focus on Staphylococcus aureus pathogenesis and biofilm, as well as treatment challenges, and novel therapeutic strategies.

RECENT FINDINGS: S. aureus biofilm creates a favorable environment that increases antibiotic resistance, impairs host immunity, and increases tolerance to nutritional deprivation. Secreted proteins from bacterial cells within the biofilm and the quorum-sensing agr system contribute to immune evasion. Additional immunoevasive properties of S. aureus include the formation of staphylococcal abscess communities (SACs) and canalicular invasion. Novel approaches to target biofilm and increase resistance to implant colonization include novel antibiotic therapy, immunotherapy, and local implant treatments. Challenges remain given the diverse mechanisms developed by S. aureus to alter the host immune responses. Further understanding of these processes should provide novel therapeutic mechanisms to enhance eradication after PJI.}, } @article {pmid29986896, year = {2018}, author = {Hill, A and Beitelshees, M and Pfeifer, BA and Jones, CH}, title = {Standardization of Pneumococcal Biofilm Release to PncO Expression, a Predictive Measurement of Virulence.}, journal = {Infection and immunity}, volume = {86}, number = {9}, pages = {}, pmid = {29986896}, issn = {1098-5522}, support = {R03 AI088485/AI/NIAID NIH HHS/United States ; R21 AI117309/AI/NIAID NIH HHS/United States ; }, mesh = {Antigens, Bacterial/*metabolism ; Bacterial Proteins/metabolism ; *Biofilms ; Humans ; Pneumococcal Infections/*microbiology ; Streptococcus pneumoniae/*pathogenicity ; Virulence/*physiology ; Virulence Factors/*metabolism ; }, abstract = {A critical component in clinical trials for vaccines against pneumococcal disease is the establishment of robust preclinical models and clinical correlates of protection, which, in the case of the causative bacterial agent Streptococcus pneumoniae, include standard sepsis/pneumonia mouse models and opsonophagocytic activity (OPA), respectively. Despite broad usage, these gold-standard measures are ill equipped to evaluate nontraditional antigens that target virulence factors beyond capsular polysaccharides and/or proteins not associated with colonization or routine growth. These assays are further complicated by observed inconsistencies in the expression of target protein antigens and in the quantity of usable bacteria provided from respective growth processes. In an effort to overcome these issues, we performed an extensive optimization study of the critical steps in a bacterial biofilm dispersion model (termed "the biofilm model") to identify conditions that yield the greatest quantity of released pneumococci displaying a consistent virulence phenotype. Using this knowledge, we developed a secondary immune absorbance assay to provide immediate insight into the phenotypic state of bacteria conditioned using the biofilm model. Specifically, positive correlations between the expression of PncO (a key virulence-associated protein antigen) and immune absorbance (R[2] = 0.96), capsule shedding, and OPA assay titers were translated into a predictive readout of virulence in sepsis and pneumonia challenge models. These results present a methodology for generating consistent lots of virulent bacteria to standardize inputs in preclinical and clinical models for testing vaccines against biofilm-associated bacteria.}, } @article {pmid29986787, year = {2018}, author = {Schrøder, SA and Eickhardt, S and Bjarnsholt, T and Nørgaard, T and Homøe, P}, title = {Morphological evidence of biofilm in chronic obstructive sialadenitis.}, journal = {The Journal of laryngology and otology}, volume = {132}, number = {7}, pages = {611-614}, doi = {10.1017/S0022215118000646}, pmid = {29986787}, issn = {1748-5460}, mesh = {Adenoma, Pleomorphic/microbiology/pathology ; Adult ; Aged ; Biofilms/*growth & development ; Case-Control Studies ; Female ; Humans ; In Situ Hybridization, Fluorescence ; Male ; Microscopy, Confocal ; Middle Aged ; Sialadenitis/*microbiology/pathology ; Submandibular Gland/*microbiology/pathology ; Young Adult ; }, abstract = {OBJECTIVE: Bacterial infection is a common finding in acute sialadenitis and may play a role in the chronicity of the condition. This study investigated if bacterial biofilm is present in submandibular chronic obstructive sialadenitis.

METHODS: A descriptive case-control study was conducted that compared 10 histological sections of submandibular glands with chronic obstructive sialadenitis, to 10 histological sections of the healthy part of submandibular glands with pleomorphic adenoma. Fluorescence in situ hybridisation and confocal laser scanning microscopy visualised evidence of bacterial biofilm.

RESULTS: In the chronic obstructive sialadenitis group, 5 out of 10 histological sections showed morphological evidence of bacterial biofilm. In the control group, there was no sign of bacterial biofilm formation.

CONCLUSION: Morphological evidence of bacterial biofilm was found in the submandibular gland sections from patients with chronic sialadenitis and suggests a role in the chronicity of submandibular chronic obstructive sialadenitis.}, } @article {pmid29986255, year = {2018}, author = {Zhao, X and Kumar, K and Gross, MA and Kunetz, TE and Wen, Z}, title = {Evaluation of revolving algae biofilm reactors for nutrients and metals removal from sludge thickening supernatant in a municipal wastewater treatment facility.}, journal = {Water research}, volume = {143}, number = {}, pages = {467-478}, doi = {10.1016/j.watres.2018.07.001}, pmid = {29986255}, issn = {1879-2448}, mesh = {Ammonia/isolation & purification ; Biofilms ; Biomass ; Bioreactors ; Chicago ; Equipment Design ; Metals/*isolation & purification ; *Microalgae ; Nitrogen/metabolism ; Phosphorus/metabolism ; Ponds ; Sewage ; Waste Disposal, Fluid/*instrumentation/*methods ; Wastewater ; Water Pollutants, Chemical/isolation & purification ; }, abstract = {This work is to evaluate pilot-scale Revolving Algal Biofilm (RAB) reactors of two heights (0.9-m and 1.8-m tall) to treat supernatant from sludge sedimentation at Metropolitan Water Reclamation District of Greater Chicago (MWRD) for removing nutrients (N and P) as well as various metals. The RAB reactors demonstrated a superior performance in N and P removal as compared to control raceway ponds. Taller 1.8-m RAB reactors performed better than 0.9-m RAB reactors in terms of total nutrient removal and algal biomass productivity. At 7-day HRT, total P (TP) and Total Kjeldahl N (TKN) removal efficiency reached to 80% and 87%, respectively, while ortho-P and ammonia removal efficiency reached to 100%. Decreasing HRT led to an enhanced TP and TKN removal rate and nutrient removal capacity. At HRT of 1.3-day, the TP removal per footprint of 1.8-m tall RAB reactors was around 7-times higher than the open pond system. The RAB reactors also showed certain capabilities of removing metals from wastewater. The study demonstrated that RAB-based treatment process is an effective method to recover nutrients from municipal wastewater.}, } @article {pmid29985503, year = {2018}, author = {Seo, Y and Hwang, J and Lee, E and Kim, YJ and Lee, K and Park, C and Choi, Y and Jeon, H and Choi, J}, title = {Engineering copper nanoparticles synthesized on the surface of carbon nanotubes for anti-microbial and anti-biofilm applications.}, journal = {Nanoscale}, volume = {10}, number = {33}, pages = {15529-15544}, doi = {10.1039/c8nr02768d}, pmid = {29985503}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Copper/*pharmacology ; Humans ; *Metal Nanoparticles ; Methylobacterium/drug effects ; Microbial Sensitivity Tests ; *Nanotubes, Carbon ; }, abstract = {Biofilms adhere to surfaces to produce extracellular polymeric substances (EPSs). EPSs grow and protect themselves from external stresses. Their formation causes a foul odor and may lead to chronic infectious diseases in animals and people. Biofilms also inhibit the contact between bacteria and antibiotics, thereby reducing their antibacterial activity. Thus, we describe novel nanostructures, a fusion of copper and multi-walled carbon nanotubes (MWCNTs), which increase antimicrobial activity against biofilms without being toxic to human cells. Simulations based on the stochastic response were performed to predict the efficiency of synthesizing nanostructures. The synthesized Cu/MWCNTs inhibit the growth of Methylobacterium spp., which forms biofilms; antimicrobial testing and cytotoxicity assessments showed that the Cu/MWCNTs were not cytotoxic to human cells. The Cu/MWCNTs come in direct contact with the bacterial cell surface, damage the cell wall, and cause secondary oxidation of reactive oxygen species. Furthermore, the Cu/MWCNTs release copper ions, which inhibit the quorum sensing in Methylobacterium spp., thereby inhibiting the expression of the genes that form biofilms. Additionally, we confirmed excellent electrical and thermal conductivity of Cu/MWCNTs as well as biofilm removal efficiency in the microfluidic channel.}, } @article {pmid29985417, year = {2018}, author = {Monmeyran, A and Thomen, P and Jonquière, H and Sureau, F and Li, C and Plamont, MA and Douarche, C and Casella, JF and Gautier, A and Henry, N}, title = {The inducible chemical-genetic fluorescent marker FAST outperforms classical fluorescent proteins in the quantitative reporting of bacterial biofilm dynamics.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {10336}, pmid = {29985417}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Escherichia coli/*physiology ; Genes, Reporter ; Green Fluorescent Proteins/genetics/*metabolism ; Luminescent Proteins/genetics/metabolism ; Microscopy, Fluorescence ; }, abstract = {To increase our understanding of bacterial biofilm complexity, real- time quantitative analyses of the living community functions are required. To reach this goal, accurate fluorescent reporters are needed. In this paper, we used the classical fluorescent genetic reporters of the GFP family and demonstrated their limits in the context of a living biofilm. We showed that fluorescence signal saturated after only a few hours of growth and related this saturation to the reduction of oxygen concentration induced by bacterial consumption. This behaviour prevents the use of GFP-like fluorescent proteins for quantitative measurement in living biofilms. To overcome this limitation, we propose the use of a recently introduced small protein tag, FAST, which is fluorescent in the presence of an exogenously applied fluorogenic dye, enabling to avoid the oxygen sensitivity issue. We compared the ability of FAST to report on biofilm growth with that of GFP and mCherry, and demonstrated the superiority of the FAST:fluorogen probes for investigating dynamics in the complex environment of a living biofilm.}, } @article {pmid29985324, year = {2018}, author = {Silva, TSO and Freitas, AR and Pinheiro, MLL and do Nascimento, C and Watanabe, E and Albuquerque, RF}, title = {Oral Biofilm Formation on Different Materials for Dental Implants.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {136}, pages = {}, pmid = {29985324}, issn = {1940-087X}, mesh = {*Biofilms ; Dental Implants/*microbiology ; Dental Materials/*chemistry ; Humans ; Microscopy, Electron, Scanning/*methods ; Surface Properties ; Titanium/*chemistry ; Zirconium/*chemistry ; }, abstract = {Dental implants and their prosthetic components are prone to bacterial colonization and biofilm formation. The use of materials that provides low microbial adhesion may reduce the prevalence and progression of peri-implant diseases. In view of the oral environment complexity and oral biofilm heterogeneity, microscopy techniques are needed that can enable a biofilm analysis of the surfaces of teeth and dental materials. This article describes a series of protocols implemented for comparing oral biofilm formation on titanium and ceramic materials for prosthetic abutments, as well as the methods involved in oral biofilms analyses at the morphological and cellular levels. The in situ model to evaluate oral biofilm formation on titanium and zirconia materials for dental prosthesis abutments as described in this study provides a satisfactory preservation of the 48 h biofilm, thereby demonstrating methodological adequacy. Multiphoton microscopy allows the analysis of an area representative of the biofilm formed on the test materials. In addition, the use of fluorophores and the processing of the images using multiphoton microscopy allows the analysis of the bacterial viability in a very heterogeneous population of microorganisms. The preparation of biological specimens for electron microscopy promotes the structural preservation of biofilm, images with good resolution, and no artifacts.}, } @article {pmid29984046, year = {2018}, author = {Lee, H and Kim, YG and Um, HS and Chang, BS and Lee, SY and Lee, JK}, title = {Efficacy of an LED toothbrush on a Porphyromonas gingivalis biofilm on a sandblasted and acid-etched titanium surface: an in vitro study.}, journal = {Journal of periodontal & implant science}, volume = {48}, number = {3}, pages = {164-173}, pmid = {29984046}, issn = {2093-2278}, abstract = {PURPOSE: The aim of this study was to evaluate the antimicrobial effect of a newly devised toothbrush with light-emitting diodes (LEDs) on Porphyromonas gingivalis attached to sandblasted and acid-etched titanium surfaces.

METHODS: The study included a control group, a commercial photodynamic therapy (PDT) group, and 3 test groups (B, BL, and BLE). The disks in the PDT group were placed in methylene blue and then irradiated with a diode laser. The B disks were only brushed, the BL disks were brushed with an LED toothbrush, and the BLE disks were placed into erythrosine and then brushed with an LED toothbrush. After the different treatments, bacteria were detached from the disks and spread on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy was performed to visualize bacterial alterations.

RESULTS: The number of viable bacteria in the BLE group was significantly lower than that in the other groups (P<0.05). Scanning electron microscopy showed that bacterial cell walls were intact in the control and B groups, but changed after commercial PDT and LED exposure.

CONCLUSIONS: The findings suggest that an LED toothbrush with erythrosine treatment was more effective than a commercial PDT kit in reducing the number of P. gingivalis cells attached to surface-modified titanium in vitro.}, } @article {pmid29983434, year = {2018}, author = {Shrestha, D and Thapa, P and Bhandari, D and Parajuli, H and Chaudhary, P and Thapa, K and Sharma, VK and Shah, PK}, title = {Biofilm Production and Antimicrobial Resistance among Uropathogens in Pediatric Cases: a Hospital Based Study.}, journal = {Journal of Nepal Health Research Council}, volume = {16}, number = {2}, pages = {178-183}, pmid = {29983434}, issn = {1999-6217}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Child, Preschool ; Drug Resistance, Bacterial/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Female ; Humans ; Infant ; Male ; Nepal ; Prospective Studies ; Urinary Tract Infections/*microbiology ; }, abstract = {BACKGROUND: The study was designed to provide account of etiological agents of urinary tract infection in pediatric patients and the antimicrobial resistance pattern plus biofilm producing profile of the isolates.

METHODS: The prospective study was conducted in Alka Hospital, Nepal with 353 clean catch urine samples from children. It was obtained during July 2014 to January 2015 which were first cultured by semi-quantitative method, followed by antimicrobial susceptibility testing and biofilm production assay on Congo red agar. Multidrug- resistance, extensively drug- resistance and pandrug- resistance among isolates were considered as per international consensus.

RESULTS: Out of 353 samples, 64 (18.13%) showed positive growth in culture, confirming urinary tract infection. E. coli, 44 (68.8%) was the predominant organism followed by Klebsiella spp. 6 (14.1%). Most E. coli were sensitive to amikacin (93.2%) followed by nitrofurantoin (86.4%), and highly resistant to ampicillin (95.5%). Of 64 isolates, 23 (35.93%) were found to be multidrug- resistant strains. Biofilm was produced by 36 (56.25%) isolates.

CONCLUSIONS: This study showed higher biofilm production and resistance to in-use antibiotics rendering ineffective for empirical use. Regular surveillance of resistance patterns should be done to regulate multidrug- resistant bugs and to ensure effective management of urinary tract infection in children in a tertiary care setups.}, } @article {pmid29980946, year = {2019}, author = {Betancourt, P and Merlos, A and Sierra, JM and Camps-Font, O and Arnabat-Dominguez, J and Viñas, M}, title = {Effectiveness of low concentration of sodium hypochlorite activated by Er,Cr:YSGG laser against Enterococcus faecalis biofilm.}, journal = {Lasers in medical science}, volume = {34}, number = {2}, pages = {247-254}, pmid = {29980946}, issn = {1435-604X}, support = {CONICYT / N° 5594/2015.//Chilean Government/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis/drug effects/*physiology ; Humans ; Imaging, Three-Dimensional ; *Lasers, Solid-State ; Root Canal Irrigants/pharmacology ; Sodium Hypochlorite/*pharmacology ; Ultrasonics ; }, abstract = {Bacteria living in biofilms exhibit altered growth phenotypes, while the biofilm provides benefits, the foremost of which is a certain protection against both immune system and killing effect by antimicrobials. Laser-activated irrigation (LAI) and passive ultrasonic irrigation (PUI) have been proposed as alternative methods for cleaning and disinfecting the root canal, as an adjuvant to conventional chemo-mechanical preparation in order to improve debridement and disinfection. Nevertheless, the potential antibacterial effect of LAI using 0.5% of sodium hypochlorite (NaOCl) has received little attention. Glass Pasteur pipettes were used to mimic single-tooth root canal and to build Enterococcus faecalis biofilm. Several irrigants and treatments were assayed for 60 s including (I) Saline, (II) NaOCl 0.5%, (III) NaOCl 5%, (IV) Er,Cr:YSGG, (V) Saline + LAI, (VI) NaOCl 0.5% + LAI, (VII) Saline + PUI, and (VIII) NaOCl 0.5% + PUI. Bacterial reduction was measured by counting the colony-forming units (CFUs). Additionally, AFM visualization and measurement of nano-roughness parameters were used to evaluate LAI effect on bacteria. NaOCl 5% unpowered and NaOCl 0.5% + LAI were capable of eliminating all bacteria, whereas non-activated saline solution and NaOCl 0.5% failed to eliminate E. faecalis. Lower efficiencies were achieved by PUI. Surface analysis by AFM revealed apparent alterations in NaOCl + LAI-treated cells. The Er,Cr:YSGG laser-activated irrigation (LAI) increased the bactericidal efficiency of 0.5% NaOCl against E. faecalis biofilm.}, } @article {pmid29980867, year = {2018}, author = {Schopf, A and Delatolla, R and Mathew, R and Tsitouras, A and Kirkwood, KM}, title = {Investigation of copper inhibition of nitrifying moving bed biofilm (MBBR) reactors during long term operations.}, journal = {Bioprocess and biosystems engineering}, volume = {41}, number = {10}, pages = {1485-1495}, doi = {10.1007/s00449-018-1976-2}, pmid = {29980867}, issn = {1615-7605}, support = {NSERC CREATE in Technologies for Microbiome Science//Natural Sciences and Engineering Research Council of Canada/ ; }, mesh = {Biofilms/*drug effects/*growth & development ; *Bioreactors ; Copper/*metabolism/*pharmacology ; Nitrification/*drug effects ; }, abstract = {Copper, a prevalent heavy metal in industrial mining wastewaters, has been shown to inhibit nitrification in wastewater treatment systems. Biofilm treatment systems have an inherent potential to reduce inhibition. This study investigated the effects of copper concentration on nitrifying biofilms in moving bed biofilm reactor (MBBR) systems across long term operation using influent ammonia concentrations representative of gold mining wastewater. Conventional isotherm models did not adequately model the attachment of copper to the biofilm. Long term nitritation was shown to be uninhibited at influent copper concentrations between 0.13 and 0.61 mg Cu/L. Nitratation was inhibited with influent copper concentrations of 0.28-0.61 mg Cu/L. There was no statistical difference in biofilm characteristics, including biofilm thickness, mass and density, across all copper concentrations tested, however, changes in biofilm morphology were observed. The demonstrated resistance of the nitrifying biofilm to copper inhibition makes the MBBR system a promising technology for treating ammonia in mining wastewaters.}, } @article {pmid29980034, year = {2018}, author = {Kaeseberg, T and Schubert, S and Oertel, R and Zhang, J and Berendonk, TU and Krebs, P}, title = {Hot spots of antibiotic tolerant and resistant bacterial subpopulations in natural freshwater biofilm communities due to inevitable urban drainage system overflows.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {242}, number = {Pt A}, pages = {164-170}, doi = {10.1016/j.envpol.2018.06.081}, pmid = {29980034}, issn = {1873-6424}, mesh = {Anti-Bacterial Agents/*metabolism ; Bacteria/drug effects ; *Biofilms ; Ciprofloxacin/pharmacology ; Drug Resistance, Microbial/*genetics ; *Environmental Monitoring ; Fresh Water ; Sewage/chemistry ; *Water Microbiology ; Water Pollution/*analysis/statistics & numerical data ; }, abstract = {Antibiotic resistant bacteria are a threat to human life. Recently, sewers have been identified as potential reservoirs. The intermittent injection of sewage into adjacent surface waters is inevitable, due to capacity limitations of the urban drainage system. Information regarding the effect to natural freshwater biofilms (NFB) due to the intermittent contaminations are scarce. Therefore, a fundamental screening is necessary. In April, we placed NFB-attachment constructions in a brook upstream and downstream from urban drainage overflow constructions. In meanwhile two sampling campaigns were conducted. The sewage and the brook water were collected to gather information about antibiotic background exposure of ciprofloxacin (CIP), clarithromycin (CLA) and doxycycline (DOX). Six months later we experimentally determined the oxygen uptake rate (OUR) of the NFB-communities after a 24 h lasting exposure with additionally dosed antibiotics. Concentrations of 0.1, 1.0 and 10.0 mg L[-1] were selected. CIP, CLA and DOX were individually dosed, and also in mixtures. The mean antibiotic background concentration in sewage was in a range of 575.5-1289.1 ng L[-1], which mainly exceeded the concentrations published in literature. The determined mean concentration in the brook was in a range of 4.6-539.0 ng L[-1]. The first significant inhibition of the OUR with individually dosed antibiotics started mainly at a concentration of 1.0 mg L[-1]. Antibiotics in a mixture with concentrations of 0.1 and 1.0 mg L[-1] were as effective as single dosed antibiotics with a concentration of 10.0 mg L[-1]. The increased antibiotic tolerance and resistance of NFB-communities downstream of the combined sewer overflow (CSO) structure was a consequence of a severe impact due to urban drainage overflows. Hence, NFB-communities downstream of CSO-constructions are hot spots of antibiotic tolerant and resistant subpopulations and access restrictions should be announced, if an infection risk is present.}, } @article {pmid29979838, year = {2018}, author = {Wu, X and Zhang, Y and Chen, X and Chen, J and Jia, M}, title = {Inflammatory immune response in rabbits with Staphylococcus aureus biofilm-associated sinusitis.}, journal = {International forum of allergy & rhinology}, volume = {8}, number = {11}, pages = {1226-1232}, pmid = {29979838}, issn = {2042-6984}, mesh = {Animals ; Biofilms ; Cytokines/genetics/immunology ; Male ; Maxillary Sinus/immunology/microbiology ; Nasal Mucosa/immunology/microbiology ; Rabbits ; Sinusitis/*immunology ; Staphylococcal Infections/*immunology ; Staphylococcus aureus ; }, abstract = {BACKGROUND: Staphylococcus aureus is the most commonly isolated bacterium from patients with surgically recalcitrant chronic rhinosinusitis (CRS). Understanding the immune responses to S aureus biofilms will provide insights into how the host response may be manipulated by therapeutic agents to improve the chances of successfully preventing and treating these infections. In this study, we investigated the inflammatory immune response in a rabbit model of S aureus biofilm-related sinusitis by analyzing the levels of some major inflammatory cytokines.

METHODS: Eighteen New Zealand white rabbits were randomly divided into 3 groups: a blank-control group; a negative-control group; and a model group. Four weeks after the biofilm-associated sinusitis models were established, the sinus mucosa was harvested and examined using hematoxylin-eosin (H&E) staining, scanning electron microscopy (SEM), reverse transcription polymerase chain reaction (RT-PCR), and western blotting. The expression levels of inflammatory cytokines were analyzed statistically.

RESULTS: Interleukin (IL)-1β, IL-8, and tumor necrosis factor (TNF)-α expression levels were significantly higher in the model group than in the blank-control group (p < 0.05); mRNA levels were increased by 1600%, 230%, and 130%, respectively, and the protein levels were increased by 180%, 100%, and 100%, respectively. In contrast, IL-4 and IL-5 mRNA levels were reduced by 44% and 70%, respectively, compared with the blank-control group (p < 0.05).

CONCLUSION: S aureus biofilms in the rabbit maxillary sinus mucosa were associated with increased IL-1β, IL-8, and TNF-α expression, and decreased IL-4 and IL-5 expression.}, } @article {pmid29977346, year = {2018}, author = {Sicard, JF and Vogeleer, P and Le Bihan, G and Rodriguez Olivera, Y and Beaudry, F and Jacques, M and Harel, J}, title = {N-Acetyl-glucosamine influences the biofilm formation of Escherichia coli.}, journal = {Gut pathogens}, volume = {10}, number = {}, pages = {26}, pmid = {29977346}, issn = {1757-4749}, abstract = {BACKGROUND: The intestinal mucous layer is a physical barrier that limits the contact between bacteria and host epithelial cells. There is growing evidence that microbiota-produced metabolites can also be specifically sensed by gut pathogens as signals to induce or repress virulence genes. Many E. coli, including adherent and invasive (AIEC) strains, can form biofilm. This property can promote their intestinal colonization and resistance to immune mechanisms. We sought to evaluate the impact of mucus-derived sugars on biofilm formation of E. coli.

RESULTS: We showed that the mucin sugar N-acetyl-glucosamine (NAG) can reduce biofilm formation of AIEC strain LF82. We demonstrated that the inactivation of the regulatory protein NagC, by addition of NAG or by mutation of nagC gene, reduced the biofilm formation of LF82 in static condition. Interestingly, real-time monitoring of biofilm formation of LF82 using microfluidic system showed that the mutation of nagC impairs the early process of biofilm development of LF82. Thus, NAG sensor NagC is involved in the early steps of biofilm formation of AIEC strain LF82 under both static and dynamic conditions. Its implication is partly due to the activation of type 1 fimbriae. NAG can also influence biofilm formation of other intestinal E. coli strains.

CONCLUSIONS: This study highlights how catabolism can be involved in biofilm formation of E. coli. Mucus-derived sugars can influence virulence properties of pathogenic E. coli and this study will help us better understand the mechanisms used to prevent colonization of the intestinal mucosa by pathogens.}, } @article {pmid29977009, year = {2018}, author = {Røder, HL and Herschend, J and Russel, J and Andersen, MF and Madsen, JS and Sørensen, SJ and Burmølle, M}, title = {Enhanced bacterial mutualism through an evolved biofilm phenotype.}, journal = {The ISME journal}, volume = {12}, number = {11}, pages = {2608-2618}, pmid = {29977009}, issn = {1751-7370}, mesh = {Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/biosynthesis ; Escherichia coli Proteins/genetics ; Paenibacillus/genetics/*physiology ; Phenotype ; Phosphorus-Oxygen Lyases/genetics ; *Symbiosis ; Xanthomonas/genetics/*physiology ; }, abstract = {Microbial communities primarily consist of multiple species that affect one another's fitness both directly and indirectly. This study showed that the cocultivation of Paenibacillus amylolyticus and Xanthomonas retroflexus exhibited facultative mutualistic interactions in a static environment, during the course of which a new adapted phenotypic variant of X. retroflexus appeared. Although the emergence of this variant was not directly linked to the presence of P. amylolyticus, its establishment in the coculture enhanced the productivity of both species due to mutations that stimulated biofilm formation. The mutations were detected in genes encoding a diguanylate cyclase predicted to synthesise cyclic-di-GMP. Examinations of the biofilm formed in cocultures of P. amylolyticus and the new variant of X. retroflexus revealed a distinct spatial organisation: P. amylolyticus only resided in biofilms in association with X. retroflexus and occupied the outer layers. The X. retroflexus variant therefore facilitated increased P. amylolyticus growth as it produced more biofilm biomass. The increase in X. retroflexus biomass was thus not at the expense of P. amylolyticus, demonstrating that interspecies interactions can shape diversification in a mutualistic coculture and reinforce these interactions, ultimately resulting in enhanced communal performance.}, } @article {pmid29974746, year = {2018}, author = {Qiao, J and Purro, M and Liu, Z and Xiong, MP}, title = {Terpyridine-Micelles for Inhibiting Bacterial Biofilm Development.}, journal = {ACS infectious diseases}, volume = {4}, number = {9}, pages = {1346-1354}, pmid = {29974746}, issn = {2373-8227}, support = {R01 DK099596/DK/NIDDK NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Chelating Agents/chemical synthesis/*chemistry/*pharmacology ; Ferric Compounds/chemistry/metabolism ; Humans ; Micelles ; Polymers/*chemical synthesis/chemistry/*pharmacology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism ; }, abstract = {Iron plays a critical role in bacterial infections and is especially critical for supporting biofilm formation. Until recently, Fe(III) was assumed to be the most relevant form of iron to chelate in therapeutic antimicrobial strategies due to its natural abundance under normal oxygen and physiologic conditions. Recent clinical data obtained from cystic fibrosis (CF) patients found that there is actually quite an abundance of Fe(II) present in sputum and that there exists a significant relationship between sputum Fe(II) concentration and severity of the disease. A biocompatible mixed micelle formed from the self-assembly of poly(lactic- co-glycolic acid)- block-methoxy poly(ethylene glycol) (PLGA- b-mPEG) and poly(lactic- co-glycolic acid)- block-poly(terpyridine)5 [PLGA- b-p(Tpy)5] polymers was prepared to chelate Fe(II) (Tpy-micelle). Tpy-micelles showed high selectivity for Fe(II) over Fe(III), decreased biofilm mass more effectively under anaerobic conditions at >4 μM Tpy-micelles, reduced bacteria growth in biofilms by >99.9% at 128 μM Tpy-micelles, effectively penetrated throughout a 1-day old biofilm, and inhibited biofilm development in a concentration-dependent manner. This study reveals that Fe(II) chelating Tpy-micelles are a promising addition to Fe(III) chelating strategies to inhibit biofilm formation in CF lung infections.}, } @article {pmid29972893, year = {2018}, author = {Sajeevan, SE and Chatterjee, M and Paul, V and Baranwal, G and Kumar, VA and Bose, C and Banerji, A and Nair, BG and Prasanth, BP and Biswas, R}, title = {Impregnation of catheters with anacardic acid from cashew nut shell prevents Staphylococcus aureus biofilm development.}, journal = {Journal of applied microbiology}, volume = {125}, number = {5}, pages = {1286-1295}, doi = {10.1111/jam.14040}, pmid = {29972893}, issn = {1365-2672}, support = {3/1/2/16/2013-Nut. and 80/924/2015-ECD-1//Indian council for Medical Research/ ; }, mesh = {Anacardic Acids/*pharmacology ; Anacardium/*chemistry ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Staphylococcus aureus/*drug effects ; }, abstract = {AIM: The effect of anacardic acid impregnation on catheter surfaces for the prevention of Staphylococcus aureus attachments and biofilm formations were evaluated.

METHODS AND RESULTS: Silicon catheter tubes were impregnated using different concentrations of anacardic acids (0·002-0·25%). Anacardic acids are antibacterial phenolic lipids from cashew nut (Anacardium occidentale) shell oil. Anacardic acid-impregnated silicon catheters revealed no significant haemolytic activity and were cytocompatible against fibroblast cell line (L929). Sustained release of anacardic acids was observed for 4 days. Anacardic acid-impregnated silicon catheters efficiently inhibited S. aureus colonization and the biofilm formation on its surface. The in vivo antibiofilm activity of anacardic acid-impregnated catheters was tested in an intraperitoneal catheter-associated medaka fish infection model. Significant reduction in S. aureus colonization on anacardic acid-impregnated catheter tubes was observed.

CONCLUSIONS: Our data suggest that anacardic acid-impregnated silicon catheters may help in preventing catheter-related staphylococcal infections.

This study opens new directions for designing antimicrobial phytochemical-coated surfaces with ideal antibiofilm properties and could be of great interest for biomedical research scientists.}, } @article {pmid29972022, year = {2018}, author = {Pushalkar, S and Ghosh, G and Xu, Q and Liu, Y and Ghogare, AA and Atem, C and Greer, A and Saxena, D and Lyons, AM}, title = {Superhydrophobic Photosensitizers: Airborne [1]O2 Killing of an in Vitro Oral Biofilm at the Plastron Interface.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {30}, pages = {25819-25829}, pmid = {29972022}, issn = {1944-8252}, support = {R41 DE026083/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Oxygen ; Photochemotherapy ; Photosensitizing Agents ; Silicon Dioxide ; Singlet Oxygen ; }, abstract = {Singlet oxygen is a potent agent for the selective killing of a wide range of harmful cells; however, current delivery methods pose significant obstacles to its widespread use as a treatment agent. Limitations include the need for photosensitizer proximity to tissue because of the short (3.5 μs) lifetime of singlet oxygen in contact with water; the strong optical absorption of the photosensitizer, which limits the penetration depth; and hypoxic environments that restrict the concentration of available oxygen. In this article, we describe a novel superhydrophobic singlet oxygen delivery device for the selective inactivation of bacterial biofilms. The device addresses the current limitations by: immobilizing photosensitizer molecules onto inert silica particles; embedding the photosensitizer-containing particles into the plastron (i.e. the fluid-free space within a superhydrophobic surface between the solid substrate and fluid layer); distributing the particles along an optically transparent substrate such that they can be uniformly illuminated; enabling the penetration of oxygen via the contiguous vapor space defined by the plastron; and stabilizing the superhydrophobic state while avoiding the direct contact of the sensitizer to biomaterials. In this way, singlet oxygen generated on the sensitizer-containing particles can diffuse across the plastron and kill bacteria even deep within the hypoxic periodontal pockets. For the first time, we demonstrate complete biofilm inactivation (>5 log killing) of Porphyromonas gingivalis, a bacterium implicated in periodontal disease using the superhydrophobic singlet oxygen delivery device. The biofilms were cultured on hydroxyapatite disks and exposed to active and control surfaces to assess the killing efficiency as monitored by colony counting and confocal microscopy. Two sensitizer particle types, a silicon phthalocyanine sol-gel and a chlorin e6 derivative covalently bound to fluorinated silica, were evaluated; the biofilm killing efficiency was found to correlate with the amount of singlet oxygen detected in separate trapping studies. Finally, we discuss the applications of such devices in the treatment of periodontitis.}, } @article {pmid29971739, year = {2018}, author = {Del Mondo, A and Pinto, G and Carbone, DA and Pollio, A and De Natale, A}, title = {Biofilm architecture on different substrates of an Oculatella subterranea (Cyanobacteria) strain isolated from Pompeii archaeological site (Italy).}, journal = {Environmental science and pollution research international}, volume = {25}, number = {26}, pages = {26079-26089}, pmid = {29971739}, issn = {1614-7499}, mesh = {Biofilms/*growth & development ; Cyanobacteria/*growth & development/isolation & purification ; Italy ; Light ; Microscopy, Confocal ; }, abstract = {The Cyanobacterium Oculatella subterranea Zammit, Billi, Albertano inhabits hypogea and stone caves and is a pioneer of different stone substrata. In this study, a strain isolated from the House of Marco Castricio (Archaeological Park of Pompeii, Italy) was identified by a polyphasic approach and used for an in vitro colonization test to verify the influence of the substrate on the biofilm architecture. Fine structure of O. subterranea microbial mats was revealed as well as filaments orientation toward light source. This aim has been achieved through confocal laser scanner microscope microscopy and computer image analysis. Moreover, bioreceptivity of five different substrates, commonly retrieved in archaeological sites of Campania, was assessed for O. subterranea. Our results show that the three-dimensional structure of O. subterranea microbial mats is poorly affected by physical and geochemical features of substrates: in fact, the porous architecture of its biofilm was preserved, independently of the materials. On the other hand, the area/perimeter ratio relative to the O. subterranea growth on tuff, brick, and porphyry showed significant differences, indicating dissimilar levels of bioreceptivity of the three substrates.}, } @article {pmid29970441, year = {2018}, author = {Cho, HH and Kwon, KC and Kim, S and Park, Y and Koo, SH}, title = {Association between Biofilm Formation and Antimicrobial Resistance in Carbapenem-Resistant Pseudomonas Aeruginosa.}, journal = {Annals of clinical and laboratory science}, volume = {48}, number = {3}, pages = {363-368}, pmid = {29970441}, issn = {1550-8080}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/drug effects/*growth & development ; Carbapenems/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/drug therapy/*genetics/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/isolation & purification ; *beta-Lactam Resistance ; }, abstract = {Recently, carbapenem resistance in P. aeruginosa is an increasingly important problem globally. Biofilm formation is a well-known pathogenic mechanism of P. aeruginosa, and the gene, pslA, plays an important role in its primary stages. We studied the association between biofilm formation and pslA in carbapenem-resistant P. aeruginosa isolates, along with antimicrobial resistance and the prevalence of metallo-β-lactamase (MBL) genes, based on the presence of pslA 82 carbapenem-resistant P. aeruginosa isolates were collected from a tertiary hospital in Daejeon, Korea, between March 2008 and June 2014. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents were determined using the agar dilution method. Biofilm formation was measured by microtiter plate assay. PCR and sequencing were used to identify pslA and the MBL gene. 76 (92.7%) carbapenem-resistant isolates were biofilm producers. These biofilm producers showed higher levels of amikacin, ceftazidime, and cefepime resistance than non-producers. pslA was detected in 71 (93.4%) biofilm-producing isolates and these results were statically significant (p<0.01). 11 isolates carrying pslA and blaIMP-6 were extremely resistant to all antimicrobials tested. In this study, biofilm formation was significantly associated with pslA Furthermore, the coexistence of pslA and the MBL gene in carbapenem-resistant isolates likely contributed to the increase in antimicrobial resistance.}, } @article {pmid29965638, year = {2018}, author = {Meng, X and Pan, Y and Zhang, H and Liao, XH and Xu, LJ and Femg, X and Shan, J}, title = {[Microbial Population Dynamics During Domestication and Cultivation of Biofilm to Remove and Enrich Phosphate].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {39}, number = {6}, pages = {2802-2809}, doi = {10.13227/j.hjkx.201710048}, pmid = {29965638}, issn = {0250-3301}, mesh = {Bacteria/*classification ; *Biofilms ; Bioreactors/*microbiology ; Phosphates/*isolation & purification ; Phosphorus ; *Waste Disposal, Fluid ; }, abstract = {The purpose of this study was to develop a method to remove and recover high concentration phosphate solutions from wastewater. An experiment was carried out to cultivate and enrich phosphorus accumulating organisms (PAOs) in the biofilm with nylon as the biological carrier using artificial water distribution. Microflora morphology, species diversity, and the genetic relationship of biofilm during the process of biofilm domestication were studied by scanning electron microscopy (SEM) and MiSeq high-throughput sequencing. In addition, the feasibility of recycling a high concentration of phosphate in the conventional biofilm within a short time was validated. The membrane was hung in the biological carrier when the reactor was operated for 10 d. After the hanging of the film succeeded, the effluent COD was below 50 mg·L[-1], the effluent phosphorus was close to zero, and the removal efficiency of phosphorus reached to above 95%. The operation was stable at this level for 40 d. The results from the SEM indicated that the microbial morphology in the biofilm was uniform with full oval-shaped spheres with a clear profile. MiSeq high-throughput sequencing indicated that the dominant phylum in the reactor included Proteobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Ignavibacteriae, and Nitrospirae. Proteobacteria, as the dominant genera, increased from 47% to 58%. Rhodocyclaceae, as the dominant phosphorus accumulating bacteria, increased from 17.9% to 28.9%. During the recovery period, the concentration of the phosphorus solution increased from 40mg·L[-1] to 82 mg·L[-1] by increasing the influent phosphate concentration and the COD concentration in the anaerobic phase, meeting the requirement of phosphorus recovery with the struvite method.}, } @article {pmid29965526, year = {2018}, author = {Fu, KM and Li, H and Zhou, HT and Qiu, FG}, title = {[Optimization of the Nitrogen Removal Performance on the CANON Process in a Biofilm Reactor: From FBBR to MBBR].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {39}, number = {5}, pages = {2256-2264}, doi = {10.13227/j.hjkx.201710064}, pmid = {29965526}, issn = {0250-3301}, mesh = {*Biofilms ; *Bioreactors ; *Denitrification ; Nitrogen/*isolation & purification ; Sewage ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {To optimize the performance of completely autotrophic nitrogen removal over nitrite (CANON), a CANON process with modified polyethylene as carriers was operated in a moving-bed biofilm reactor (MBBR), using synthetic inorganic ammonia-rich wastewater (NH4[+]-N about 400 mg ·L[-1]) as influent at 30℃±1℃. With an HRT of 6 h, pH at 7.8, and filling rate of 35%, the average removal rate of NH4[+]-N and TN reached 74.28% and 87.93%, respectively, and the highest removals reached 84.68% and 98.82%, respectively, while the value of ΔNO3[-]/ΔTN was 0.12, which was close to the theoretical value of 0.127. This suggested that CANON sludge gradually adapted to the environment in the MBBR and began to enter the stable stage. Compared with a fixed-bed biofilm reactor (FBBR) under the same influent and operating conditions, the mean square error of MBBR and FBBR in terms of NH4[+]-N removal rate, TN removal rate, and TN removal load were 8.31% and 14.06%, 7.09% and 1.79%, 0.17 kg ·(m[3] ·d)[-1] and 0.27 kg ·(m[3] ·d)[-1], respectively, the former are lower than the latter. Moreover, while DO concentrations of MBBR and FBBR were 1.96 mg·L[-]1 and 3.09 mg ·L[-1], respectively, their TN removals of per liter carriers were 0.53 kg ·(m[3] ·d)[-1] and 0.37 kg ·(m[3] ·d)[-1]. Therefore, it was concluded that:① MBBR had a more stable nitrogen removal performance than did of FBBR, and ② MBBR had a higher TN removals of per liter carriers than did FBBR in addition to the higher utilization rate of oxygen.}, } @article {pmid29965474, year = {2018}, author = {Zhao, Q and Bian, W and Li, J and Wang, WX and Sun, YQ and Liang, DB and Zhang, SY}, title = {[Characteristics of Biofilm During the Transition Process of Complete Nitrification and Partial Nitrification].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {39}, number = {3}, pages = {1278-1285}, doi = {10.13227/j.hjkx.201708055}, pmid = {29965474}, issn = {0250-3301}, mesh = {Ammonia ; Bacteria/metabolism ; *Biofilms ; *Bioreactors ; In Situ Hybridization, Fluorescence ; Microscopy, Confocal ; *Nitrification ; Nitrites/*isolation & purification ; }, abstract = {The objective of the study was to investigate the change of biofilm characteristics when implementing the procedure of partial nitrification. A ratio control strategy (DO/NH4[+]-N) was taken to achieve partial nitrification, and biofilm samples were obtained at 10.27%, 52.12%, and 93.54% of the nitrite accumulation rate. The amount and spatial distribution of total bacteria, ammonia oxidizing bacteria (AOB), and nitrite oxidative bacteria (NOB) were observed by fluorescence in situ hybridization (FISH) and confocal laser scanning microscope (CLSM) through a three-dimensional excitation emission matrix (EEM) to observe the secretion and composition changes of extracellular polymer substances. Ratio control successfully enriched AOB and achieved partial nitrification under conditions when NOB was not completely washed. Heterotrophic bacteria and nitrifying bacteria coexist in the biofilm. The heterotrophic bacteria were in the outer layer, but nitrifying bacteria were distributed in the biofilm surface at 6-25 μm. During the process of short-range nitrification, the AOB/NOB value gradually increased, and the stable operation period was as high as 15.56. During the operation of the reactor, EPS and microbial flora changes are closely related. When microbial activity decreased, EPS secretion decreased. During the stable operation period of partial nitrification, NOB and other bacteria that are non-resistant to high nitrite nitrous acid declined, and the fluorescence intensity of aromatic protein-like bacteria decreased. However, the three-dimensional fluorescence spectra showed that the chemical composition of EPS was not obvious during the process of partial nitrification.}, } @article {pmid29964944, year = {2017}, author = {Wang, YZ and Cheng, PF and Liu, DF and Liu, TZ}, title = {[Purification Effect of Piggery Wastewater with Chlorella pyrenoidosa by Immobilized Biofilm-Attached Culture].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {38}, number = {8}, pages = {3354-3361}, doi = {10.13227/j.hjkx.201701113}, pmid = {29964944}, issn = {0250-3301}, mesh = {Ammonia/metabolism ; Animals ; *Biofilms ; Biomass ; Cells, Immobilized/metabolism ; Chlorella/*metabolism ; Metals, Heavy/isolation & purification ; Microalgae ; Nitrogen/metabolism ; Phosphorus/metabolism ; Swine ; *Wastewater ; *Water Purification ; }, abstract = {Piggery wastewater treatment with microalgae is a biological recycling technology. To evaluate the purification effect, this study investigated the treatment of piggery wastewater at different dilution ratios with Chlorella pyrenoidosa by attached cultivation and lipid production of algae cells and explored the tolerance of Chlorella pyrenoidosa to the piggery wastewater, which has high ammonia nitrogen. The piggery wastewater was diluted with purified water 1-, 2-, 5-, and 10-fold in culture media. The removal efficiencies of COD, ammonia nitrogen, total nitrogen, and total phosphorus and the enrichment effect of the heavy metals copper, zinc, and iron were measured. Meanwhile, we investigated the lipid production of Chlorella pyrenoidosa in variously diluted wastewater (1-, 2-, 5-, and 10-fold). It turned out that the purification effects of COD, ammonia nitrogen, total nitrogen, and total phosphorus were best when the piggery wastewater was diluted 5-fold, and the removal efficiencies were 86.8%, 94.1%, 85.2%, and 84.3%, respectively. Correspondingly, the lipid content was as high as 32.7%, and the removal efficiencies of the heavy metals copper, zinc, and iron were 72.9%, 70.0%, and 73.0%, respectively. The biomass productivity was 4.21 g·(m[2]·d)[-1] at the end of the experiment. This research makes an effective connection between microalgae and piggery wastewater, which is difficult to purify deeply, and provides a theoretical basis for achieving algal biofuel production and decreasing the cost of wastewater treatment.}, } @article {pmid29964585, year = {2017}, author = {Sun, YQ and Bian, W and Wang, M and Zhao, Q and Wang, WX and Liang, DB and Li, J}, title = {[Comparison of Start-up and Stable Performance of Nitritation in Activated Sludge and Biofilm Processes in a SBR].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {38}, number = {12}, pages = {5222-5228}, doi = {10.13227/j.hjkx.201706018}, pmid = {29964585}, issn = {0250-3301}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Nitrites ; Nitrogen/*chemistry ; Oxygen/analysis ; Sewage/*microbiology ; }, abstract = {This study investigates the effect of increased hydraulic retention time (HRT) and dissolved oxygen (DO) on the destruction and restoration of the performance of activated sludge and biofilm sequencing batch reactor (SBR) nitritation after the processes were simultaneously started up and stably operated at room temperature (25℃). The results showed that was easier to start nitritation in an activated sludge reactor, but nitritation was destroyed when DO was 2-2.5 mg·L[-1]. The performance could be restored by reducing DO to 0.5-1 mg·L[-1]. The biofilm process was not affected by DO. Prolonging HRT destroyed the stable operation of the two processes. Compared with the method of biofilm, the activated sludge method had less resistance, but restoring performance was better than for the biofilm process after shortening the HRT. Subsequently, the temperature (20, 15, and 10℃) was continuously reduced to investigate the synergistic effect of DO and temperature on nitritation stabilization. The results showed that the reduction of temperature destroyed the stable operation of nitritation, but the reduction of DO concentration could compensate for the adverse effects of temperature reduction. In addition, when the temperature was higher than 20℃, the rate of nitritation in the activated sludge process was better than that in thebiofilm method. At low temperature (below 15℃), a stable operation of nitritation was easier to achieve with the biofilm method. The capacity of the activated sludge process was hardly changed at 10℃. The above conclusions were confirmed by molecular microbiological analysis, and it was found that the stable operation of nitritation could be achieved without complete wash-out of the nitrite-oxidizing bacteria (NOB).}, } @article {pmid29964099, year = {2018}, author = {Chowdhury, D and Tahir, S and Legge, M and Hu, H and Prvan, T and Johani, K and Whiteley, GS and Glasbey, TO and Deva, AK and Vickery, K}, title = {Transfer of dry surface biofilm in the healthcare environment: the role of healthcare workers' hands as vehicles.}, journal = {The Journal of hospital infection}, volume = {100}, number = {3}, pages = {e85-e90}, doi = {10.1016/j.jhin.2018.06.021}, pmid = {29964099}, issn = {1532-2939}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; *Environmental Microbiology ; Hand/*microbiology ; *Health Personnel ; Humans ; Staphylococcus aureus/*growth & development/*isolation & purification ; }, abstract = {BACKGROUND: Dry surface biofilms (DSBs) persist for extended periods in hospital, and may play a significant role in transmission of healthcare-associated infections.

AIM: To determine whether DSBs may be transferred from hospital surfaces to healthcare workers' hands.

METHOD: Twelve-day Staphylococcus aureus DSB was grown on polycarbonate and glass coupons in a CDC Biofilm Reactor[®]. A total of 1.8 × 10[6] and 8.8 × 10[5] bacteria grew on the polycarbonate and glass coupons respectively. Transmission was tested by lifting the coupon with forefinger and thumb of ungloved hands to a height of 30 cm, then touching horse blood agar (HBA) plates 19 sequential times. Transferred bacterial number was determined by colony-forming units. The effect of DSB wetting on biofilm transfer was tested with 5% neutral detergent treatment for 5 s.

FINDINGS: Between 5.5 and 6.6% of the DSB bacteria were transferred to hands with one touch and ∼20% were then transferred to HBA with one touch, giving an overall transfer rate of 1.26% and 1.04% for polycarbonate and glass coupons, respectively. Detergent treatment had little effect on bacterial removal from coupons, but, for biofilm grown on polycarbonate, significantly increased transferral to HBA (P < 0.001) to 5.2%. Large numbers of bacteria were transferred by bare hands to multiple fomites. One-third of polycarbonate coupons transferred >1000 colonies during the first five sequential touches. Sufficient bacteria to cause infection were transmitted up to 19 times following one touch of the DSB.

CONCLUSION: DSB bacteria are transferred by hands from one fomite to multiple fomites, suggesting that DSB may serve as a persistent environmental source of pathogens.}, } @article {pmid29963020, year = {2018}, author = {Kim, YG and Lee, JH and Raorane, CJ and Oh, ST and Park, JG and Lee, J}, title = {Herring Oil and Omega Fatty Acids Inhibit Staphylococcus aureus Biofilm Formation and Virulence.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1241}, pmid = {29963020}, issn = {1664-302X}, abstract = {Staphylococcus aureus is notorious for its ability to become resistant to antibiotics and biofilms play a critical role in antibiotic tolerance. S. aureus is also capable of secreting several exotoxins associated with the pathogenesis of sepsis and pneumonia. Thus, the objectives of the study were to examine S. aureus biofilm formation in vitro, and the effects of herring oil and its main components, omega fatty acids [cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) and cis-5,8,11,14,17-eicosapentaenoic acid (EPA)], on virulence factor production and transcriptional changes in S. aureus. Herring oil decreased biofilm formation by two S. aureus strains. GC-MS analysis revealed the presence of several polyunsaturated fatty acids in herring oil, and of these, two omega-3 fatty acids, DHA and EPA, significantly inhibited S. aureus biofilm formation. In addition, herring oil, DHA, and EPA at 20 μg/ml significantly decreased the hemolytic effect of S. aureus on human red blood cells, and when pre-treated to S. aureus, the bacterium was more easily killed by human whole blood. Transcriptional analysis showed that herring oil, DHA, and EPA repressed the expression of the α-hemolysin hla gene. Furthermore, in a Caenorhabditis elegans nematode model, all three prolonged nematode survival in the presence of S. aureus. These findings suggest that herring oil, DHA, and EPA are potentially useful for controlling persistent S. aureus infection.}, } @article {pmid29961193, year = {2018}, author = {Boyle, KK and Wood, S and Tarity, TD}, title = {Low-Virulence Organisms and Periprosthetic Joint Infection-Biofilm Considerations of These Organisms.}, journal = {Current reviews in musculoskeletal medicine}, volume = {11}, number = {3}, pages = {409-419}, pmid = {29961193}, issn = {1935-973X}, abstract = {PURPOSE OF REVIEW: The purpose of this manuscript is to provide a critical review of peer-reviewed literature over the last 5 years related to low virulent organisms associated with periprosthetic joint infection (PJI). We evaluated the most common organisms, the diagnostic challenges, and the novel tools available in the perioperative workup of PJI as well as the current understanding of how biofilm potentiates the indolent clinical presentation and explore a possible shift in the surgical management of these patients.

RECENT FINDINGS: Biofilm actively prevents macrophage phagocytosis by suppressing proinflammatory activity through the recruitment of myeloid-derived suppressor cells. Given the appropriate host and organism conditions, increased utilization of one-stage exchange arthroplasty in the surgical treatment of these low virulent infections may be on the rise. Biomarkers and molecular techniques offer encouraging results to diagnose low virulent organisms and future research focused on the disruption of biofilm may ultimately give rise to improved treatment strategies.}, } @article {pmid29960245, year = {2018}, author = {Augusto, MR and Camiloti, PR and Souza, TSO}, title = {Fast start-up of the single-stage nitrogen removal using anammox and partial nitritation (SNAP) from conventional activated sludge in a membrane-aerated biofilm reactor.}, journal = {Bioresource technology}, volume = {266}, number = {}, pages = {151-157}, doi = {10.1016/j.biortech.2018.06.068}, pmid = {29960245}, issn = {1873-2976}, mesh = {Ammonium Compounds ; *Biofilms ; Bioreactors ; Denitrification ; *Nitrogen ; Oxidation-Reduction ; *Sewage ; }, abstract = {The single-stage nitrogen removal using anammox and partial nitritation (SNAP) is a promising alternative for low-cost ammonium removal from wastewaters. This study aimed to evaluate the anammox biomass enrichment and SNAP process start-up in a laboratory-scale membrane-aerated biofilm reactor (MABR) at nitrogen loading rates of 50 g N.m[-3].d[-1] (period 1) and 100 g N.m[-3].d[-1] (period 2). Anammox activity was observed after 48 days, and the SNAP process was stable after 80 days. In period 1, the average total nitrogen (TN) removal was 78 ± 6%, and the maximum removal was 84%. In period 2, the average TN removal was 61 ± 5%, and the maximum was 69%. Higher dissolved oxygen levels may have caused imbalances in the microbial community in period 2, decreasing the reactor performance. These results demonstrated the potential of the MABR for the fast implementation of the single-stage partial nitritation and anammox processes.}, } @article {pmid29958172, year = {2018}, author = {Li, H and Zhou, L and Lin, H and Xu, X and Jia, R and Xia, S}, title = {Dynamic response of biofilm microbial ecology to para-chloronitrobenzene biodegradation in a hydrogen-based, denitrifying and sulfate-reducing membrane biofilm reactor.}, journal = {The Science of the total environment}, volume = {643}, number = {}, pages = {842-849}, doi = {10.1016/j.scitotenv.2018.06.245}, pmid = {29958172}, issn = {1879-1026}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Hydrogen ; Nitrobenzenes/*metabolism ; Sulfates ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The dynamic response of biofilm microbial ecology to para-chloronitrobenzene (p-CNB) biodegradation was systematically evaluated according to the composition and loading of electron acceptors and H2 availability (controlled by H2 pressure) in a hydrogen-based, denitrifying and sulfate-reducing membrane biofilm reactor (MBfR). To accomplish this, a laboratory-scale MBfR was set up and operated with different influent p-CNB concentrations (0, 2, and 5 mg p-CNB/L) and H2 pressures (0.04 and 0.05 MPa). Polymerase chain reaction-denaturing gel electrophoresis (PCR-DGGE) and cloning were then applied to investigate the bacterial diversity response of biofilm during p-CNB biodegradation. The results showed that denitrification and sulfate reduction largely controlled the total demand for H2. Additionally, the DGGE fingerprint demonstrated that the addition of p-CNB, which acted as an electron acceptor, was a critical factor in the dynamics of the MBfR biofilm microbial ecology. The presence of p-CNB also had a more advantageous effect on the biofilm microbial community. Additionally, clone library analysis showed that Proteobacteria (especially beta- and gamma-) comprised the majority of the microbial biofilm response to p-CNB biodegradation, and that Pseudomonas sp. (Gammaproteobacteria) played a significant role in the biotransformation of p-CNB to aniline.}, } @article {pmid29956641, year = {2018}, author = {Kamble, SP and Shinde, KD}, title = {Anti-biofilm Activity Against Gram-Positive Bacteria by Biologically Synthesized Silver Nanoparticles Using Curcuma longa.}, journal = {Pharmaceutical nanotechnology}, volume = {6}, number = {3}, pages = {165-170}, doi = {10.2174/2211738506666180629142001}, pmid = {29956641}, issn = {2211-7393}, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/*drug effects ; *Curcuma ; Metal Nanoparticles/*administration & dosage/chemistry ; Plant Extracts/*chemistry ; Plant Tubers/chemistry ; Silver/*administration & dosage/chemistry ; Staphylococcus/*drug effects/physiology ; }, abstract = {OBJECTIVE: To assess the biofilm inhibition activity of biosynthesized silver nanoparticles (AgNPs) using Curcuma longa.

METHOD: Characterizations of these biogenic nanoparticles were done by UV-Vis spectroscopy, TEM, EDX and nanoparticles tracking analyzer. The antibiofilm activity of AgNPs against S. aureus and S. pneumoniae was carried out by 96 well plate method. Further, the combined effect of AgNPs with the antibiotic was studied against S. aureus and S. pneumoniae.

RESULTS: UV-spectroscopic analysis showed a surface plasmon resonance peak at 415nm. The shape of AgNPs is spherical with an average size of 20-40 nm while the elemental silver was confirmed by EDX analysis. These biosynthesized AgNPs have anti-biofilm activity against S. aureus and S. pneumoniae. Furthermore, the combined effect of AgNPs with an antibiotic, showed enhanced anti-biofilm activity against both the strains under study.

CONCLUSION: C. longa mediated AgNPs showed potent anti-biofilm activity.}, } @article {pmid29956605, year = {2018}, author = {Chouhan, OP and Biswas, S}, title = {Subtle Changes Due to Mutations in the GGDEF Domain Result in Loss of Biofilm Forming Activity in the VC0395_0300 Protein from Vibrio cholerae, but No Major Change in the Overall Structure.}, journal = {Protein and peptide letters}, volume = {25}, number = {8}, pages = {740-747}, doi = {10.2174/0929866525666180628162405}, pmid = {29956605}, issn = {1875-5305}, mesh = {Bacterial Proteins/chemistry/*genetics/metabolism ; *Biofilms ; Escherichia coli Proteins/chemistry/*genetics/metabolism ; Mutagenesis, Site-Directed ; Phosphorus-Oxygen Lyases/chemistry/*genetics/metabolism ; Protein Conformation ; Vibrio cholerae/*genetics/*physiology ; }, abstract = {BACKGROUND: Cyclic-di-GMP (c-di-GMP) is a ubiquitous secondary messenger molecule in bacteria synthesized by diguanylate cyclases. This universal messenger regulates diverse cellular functions in bacteria at the transcriptional, translational and posttranslational levels. The cellular functions regulated by c-di-GMP include cell motility, cell cycle progression, virulence, biofilm formation, antibiotic production and other unknown functions. The VC0395_0300 protein from the chromosome I of the Vibrio cholerae classical strain O395, serotype O1 has been established to be a diguanylate cyclase with a necessary role in biofilm formation.

OBJECTIVE: Mutations in the central position of the GGEEF active site of VC0395_0300 protein have been created by site-directed mutagenesis. The conditions for maximum production of mutated protein have been optimized. While there is a significant loss-of-biofilm-forming activity in the mutants, the basis for the same needed an investigation at the structural level.

METHODS: Subsequently, the mutant proteins have been characterized using spectrofluorimetry and circular dichroism spectroscopy.

RESULTS: While the unfolding pattern of the mutant proteins shows some changes with respect to the wild type, the overall structure of the protein does not show significant changes due to the mutagenesis, despite the absence of biofilm formation in the mutants.

CONCLUSION: This led us to conclude that whatever changes that occur in the mutated proteins, do not disturb the GGEEF domain architecture, but are restricted to the local architecture, and are hence, subtle in nature.}, } @article {pmid29955926, year = {2018}, author = {Chen, J and Li, N and Xie, S and Chen, C}, title = {Biofilm and planktonic bacterial communities in a drinking water distribution system supplied with untreated groundwater.}, journal = {Archives of microbiology}, volume = {200}, number = {9}, pages = {1323-1331}, doi = {10.1007/s00203-018-1546-7}, pmid = {29955926}, issn = {1432-072X}, mesh = {Biofilms/growth & development ; Disinfection ; Drinking Water/*microbiology ; Groundwater/*microbiology ; *Microbiota ; Nitrates/analysis ; Nitrites/analysis ; Plankton/classification/growth & development ; Proteobacteria/*classification/*isolation & purification ; Water Microbiology ; Water Purification ; Water Quality ; }, abstract = {It is known that both disinfection and water quality can influence the bacterial communities in a drinking water distribution system (DWDS). Here, we hypothesized that bacterial communities in a DWDS with untreated groundwater with no prior purification and disinfection might differ from those in a DWDS with disinfected surface water. The present study applied Illumina MiSeq sequencing to investigate biofilm and planktonic bacterial communities in a DWDS fed with untreated groundwater (receiving no prior purification and disinfection). Considerable differences in bacterial richness (Chao1 richness estimator: 389-745 for water and 392-485 for biofilm), diversity (Shannon diversity index: 2.70-3.77 for water and 2.53-3.66 for biofilm) and community structure existed among both DWDS waters and biofilms. Biofilm and planktonic bacterial communities had distinct structures. The service time of DWDS could affect biofilm bacterial richness, diversity and community structure. Moreover, planktonic bacterial diversity and community structure might be influenced by NO2[-] concentration, while planktonic bacterial richness was related to NO3[-] concentration. Proteobacteria dominated in both biofilm and planktonic bacterial communities. Higher concentrations of NO2[-] favored the deltaproteobacterial proportion, but lowered the gammaproteobacterial proportion in drinking water. Overall, our study indicates that bacterial communities in a DWDS could be influenced by a variety of factors, such as habitats (water or biofilm), DWDS service time, and water chemistry.}, } @article {pmid29955077, year = {2018}, author = {Di Domenico, EG and Cavallo, I and Bordignon, V and Prignano, G and Sperduti, I and Gurtner, A and Trento, E and Toma, L and Pimpinelli, F and Capitanio, B and Ensoli, F}, title = {Inflammatory cytokines and biofilm production sustain Staphylococcus aureus outgrowth and persistence: a pivotal interplay in the pathogenesis of Atopic Dermatitis.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {9573}, pmid = {29955077}, issn = {2045-2322}, mesh = {Anti-Infective Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Child ; Child, Preschool ; Coagulase/metabolism ; Cytokines/*metabolism ; Dermatitis, Atopic/*metabolism/*microbiology/pathology ; Drug Resistance, Bacterial/drug effects ; Female ; Humans ; Infant ; Inflammation Mediators/*metabolism ; Male ; Microbial Sensitivity Tests ; Oxacillin/pharmacology ; Severity of Illness Index ; Skin/microbiology/pathology ; Staphylococcus aureus/drug effects/*growth & development/isolation & purification ; }, abstract = {Individuals with Atopic dermatitis (AD) are highly susceptible to Staphylococcus aureus colonization. However, the mechanisms driving this process as well as the impact of S. aureus in AD pathogenesis are still incompletely understood. In this study, we analysed the role of biofilm in sustaining S. aureus chronic persistence and its impact on AD severity. Further we explored whether key inflammatory cytokines overexpressed in AD might provide a selective advantage to S. aureus. Results show that the strength of biofilm production by S. aureus correlated with the severity of the skin lesion, being significantly higher (P < 0.01) in patients with a more severe form of the disease as compared to those individuals with mild AD. Additionally, interleukin (IL)-β and interferon γ (IFN-γ), but not interleukin (IL)-6, induced a concentration-dependent increase of S. aureus growth. This effect was not observed with coagulase-negative staphylococci isolated from the skin of AD patients. These findings indicate that inflammatory cytokines such as IL1-β and IFN-γ, can selectively promote S. aureus outgrowth, thus subverting the composition of the healthy skin microbiome. Moreover, biofilm production by S. aureus plays a relevant role in further supporting chronic colonization and disease severity, while providing an increased tolerance to antimicrobials.}, } @article {pmid29952074, year = {2018}, author = {Fila, G and Krychowiak, M and Rychlowski, M and Bielawski, KP and Grinholc, M}, title = {Antimicrobial blue light photoinactivation of Pseudomonas aeruginosa: Quorum sensing signaling molecules, biofilm formation and pathogenicity.}, journal = {Journal of biophotonics}, volume = {11}, number = {11}, pages = {e201800079}, doi = {10.1002/jbio.201800079}, pmid = {29952074}, issn = {1864-0648}, mesh = {Animals ; Biofilms/*growth & development/radiation effects ; Caenorhabditis elegans/microbiology ; Dose-Response Relationship, Radiation ; Intracellular Space/metabolism/radiation effects ; *Light ; Microbial Viability/*radiation effects ; Protoporphyrins/metabolism ; Pseudomonas aeruginosa/cytology/metabolism/*physiology/*radiation effects ; Quorum Sensing/*radiation effects ; Reactive Oxygen Species/metabolism ; Signal Transduction/*radiation effects ; Virulence/radiation effects ; }, abstract = {Pseudomonas aeruginosa is a common causative bacterium of acute and chronic infections that have been responsible for high mortality over the past decade. P. aeruginosa produces many virulence factors such as toxins, enzymes and dyes that are strongly dependent on quorum sensing (QS) signaling systems. P. aeruginosa has three major QS systems (las, rhl and Pseudomonas quinolone signal) that regulate the expression of genes encoding virulence factors as well as biofilm production and maturation. Antimicrobial blue light (aBL) is considered a therapeutic option for bacterial infections and has other benefits, such as reducing bacterial virulence. Therefore, this study investigated the efficacy of aBL to reduce P. aeruginosa pathogenicity. aBL treatment resulted in the reduced activity of certain QS signaling molecules in P. aeruginosa and inhibited biofilm formation. in vivo tests using a Caenorhabditis elegans infection model indicated that sublethal aBL decreased the pathogenicity of P. aeruginosa. aBL may be a new virulence-targeting therapeutic approach.}, } @article {pmid29950836, year = {2018}, author = {Singh, P and Pandit, S and Garnæs, J and Tunjic, S and Mokkapati, VR and Sultan, A and Thygesen, A and Mackevica, A and Mateiu, RV and Daugaard, AE and Baun, A and Mijakovic, I}, title = {Green synthesis of gold and silver nanoparticles from Cannabis sativa (industrial hemp) and their capacity for biofilm inhibition.}, journal = {International journal of nanomedicine}, volume = {13}, number = {}, pages = {3571-3591}, pmid = {29950836}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Cannabis/*chemistry ; Dynamic Light Scattering ; Escherichia coli/drug effects/physiology ; Gold/*chemistry/pharmacology ; Green Chemistry Technology/*methods ; Humans ; Ions ; Kinetics ; Metal Nanoparticles/*chemistry/ultrastructure ; Microbial Sensitivity Tests ; Particle Size ; Plant Extracts/chemistry ; Pseudomonas aeruginosa/drug effects/physiology ; Silver/*chemistry/pharmacology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Spectrophotometry, Ultraviolet ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {BACKGROUND: Cannabis sativa (hemp) is a source of various biologically active compounds, for instance, cannabinoids, terpenes and phenolic compounds, which exhibit antibacterial, antifungal, anti-inflammatory and anticancer properties. With the purpose of expanding the auxiliary application of C. sativa in the field of bio-nanotechnology, we explored the plant for green and efficient synthesis of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs).

METHODS AND RESULTS: The nanoparticles were synthesized by utilizing an aqueous extract of C. sativa stem separated into two different fractions (cortex and core [xylem part]) without any additional reducing, stabilizing and capping agents. In the synthesis of AuNPs using the cortex enriched in bast fibers, fiber-AuNPs (F-AuNPs) were achieved. When using the core part of the stem, which is enriched with phenolic compounds such as alkaloids and cannabinoids, core-AuNPs (C-AuNPs) and core-AgNPs (C-AgNPs) were formed. Synthesized nanoparticles were character-ized by UV-visible analysis, transmission electron microscopy, atomic force microscopy, dynamic light scattering, Fourier transform infrared, and matrix-assisted laser desorption/ionization time-of-flight. In addition, the stable nature of nanoparticles has been shown by thermogravimetric analysis and inductively coupled plasma mass spectrometry (ICP-MS). Finally, the AgNPs were explored for the inhibition of Pseudomonas aeruginosa and Escherichia coli biofilms.

CONCLUSION: The synthesized nanoparticles were crystalline with an average diameter between 12 and 18 nm for F-AuNPs and C-AuNPs and in the range of 20-40 nm for C-AgNPs. ICP-MS analysis revealed concentrations of synthesized nanoparticles as 0.7, 4.5 and 3.6 mg/mL for F-AuNPs, C-AuNPs and C-AgNPs, respectively. Fourier transform infrared spectroscopy revealed the presence of flavonoids, cannabinoids, terpenes and phenols on the nanoparticle surface, which could be responsible for reducing the salts to nanoparticles and further stabilizing them. In addition, the stable nature of synthesized nanoparticles has been shown by thermogravimetric analysis and ICP-MS. Finally, the AgNPs were explored for the inhibition of P. aeruginosa and E. coli biofilms. The nanoparticles exhibited minimum inhibitory concentration values of 6.25 and 5 µg/mL and minimum bactericidal concentration values of 12.5 and 25 µg/mL against P. aeruginosa and E. coli, respectively.}, } @article {pmid29949876, year = {2018}, author = {Beitelshees, M and Hill, A and Jones, CH and Pfeifer, BA}, title = {Phenotypic Variation during Biofilm Formation: Implications for Anti-Biofilm Therapeutic Design.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {7}, pages = {}, pmid = {29949876}, issn = {1996-1944}, abstract = {Various bacterial species cycle between growth phases and biofilm formation, of which the latter facilitates persistence in inhospitable environments. These phases can be generally characterized by one or more cellular phenotype(s), each with distinct virulence factor functionality. In addition, a variety of phenotypes can often be observed within the phases themselves, which can be dependent on host conditions or the presence of nutrient and oxygen gradients within the biofilm itself (i.e., microenvironments). Currently, most anti-biofilm strategies have targeted a single phenotype; this approach has driven effective, yet incomplete, protection due to the lack of consideration of gene expression dynamics throughout the bacteria’s pathogenesis. As such, this article provides an overview of the distinct phenotypes found within each biofilm development phase and demonstrates the unique anti-biofilm solutions each phase offers. However, we conclude that a combinatorial approach must be taken to provide complete protection against biofilm forming bacterial and their resulting diseases.}, } @article {pmid29948830, year = {2018}, author = {Kang, D and Kirienko, NV}, title = {Interdependence between iron acquisition and biofilm formation in Pseudomonas aeruginosa.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {56}, number = {7}, pages = {449-457}, pmid = {29948830}, issn = {1976-3794}, support = {K22 AI110552/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cystic Fibrosis/microbiology ; Host-Pathogen Interactions ; Humans ; Iron/*metabolism ; Mice ; Polysaccharides, Bacterial/physiology ; Pseudomonas aeruginosa/growth & development/immunology/pathogenicity/*physiology ; Siderophores/physiology ; Virulence Factors ; }, abstract = {Bacterial biofilms remain a persistent threat to human healthcare due to their role in the development of antimicrobial resistance. To combat multi-drug resistant pathogens, it is crucial to enhance our understanding of not only the regulation of biofilm formation, but also its contribution to bacterial virulence. Iron acquisition lies at the crux of these two subjects. In this review, we discuss the role of iron acquisition in biofilm formation and how hosts impede this mechanism to defend against pathogens. We also discuss recent findings that suggest that biofilm formation can also have the reciprocal effect, influencing siderophore production and iron sequestration.}, } @article {pmid29948696, year = {2018}, author = {Lin, H and Wang, C and Zhao, H and Chen, G and Chen, X}, title = {Interaction between copper and extracellular nucleic acids in the EPS of unsaturated Pseudomonas putida CZ1 biofilm.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {24}, pages = {24172-24180}, pmid = {29948696}, issn = {1614-7499}, support = {21778070//National Natural Science Foundation of China/ ; }, mesh = {Biofilms ; Copper/*chemistry/toxicity ; DNA/chemistry ; Extracellular Polymeric Substance Matrix/*genetics ; Pseudomonas putida/drug effects/*genetics/physiology ; Random Amplified Polymorphic DNA Technique ; X-Ray Absorption Spectroscopy ; }, abstract = {The role of extracellular DNA (eDNA) in biofilm in heavy metal complexation has been little reported. In this study, the interaction between the extracellular fraction of unsaturated biofilms and Cu[2+] was studied using random amplified polymorphic DNA (RAPD) and synchrotron-based X-ray absorption spectroscopy (XAS) analyses. Under Cu[2+] stress, the amount of eDNA was about 10-fold higher than the treatment without Cu[2+] stress, which was substantially more than the amount of intracellular DNA (iDNA) present in the biofilm. The eDNA content increased significantly under Cu[2+] stress and higher eDNA contents were found in colloidal extracellular polymeric substances (EPS) than in capsular EPS in Luria-Bertani medium. It was found that the composition of eDNA was distinctly changed under conditions of Cu[2+] stress compared with the treatments without Cu[2+] treatments, with specific eDNA bands appearing under Cu[2+] treatments as revealed by RAPD analyses. X-ray absorption fine structure (XAFS) analysis assessing the molecular speciation of copper showed that copper in the secreted eDNA mainly existed as species resembling Cu3(PO4)2, followed by Cu-citrate species. This study investigated the interaction between copper and eDNA in unsaturated Pseudomonas putida CZ1 biofilms. Potential function of eDNA in biofilms under Cu[2+] stress was found.}, } @article {pmid29948119, year = {2018}, author = {Cho, K and Jeong, D and Lee, S and Bae, H}, title = {Chlorination caused a shift in marine biofilm niches on microfiltration/ultrafiltration and reverse osmosis membranes and UV irradiation effectively inactivated a chlorine-resistant bacterium.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {16}, pages = {7183-7194}, doi = {10.1007/s00253-018-9111-5}, pmid = {29948119}, issn = {1432-0614}, mesh = {*Aquatic Organisms/drug effects/radiation effects ; Biofilms/*drug effects ; Chlorine/*pharmacology ; Drug Resistance, Microbial/*radiation effects ; Microbial Viability/*drug effects/*radiation effects ; Osmosis ; Ultrafiltration ; *Ultraviolet Rays ; }, abstract = {The effect of chlorine disinfection on marine biofilm populations and communities formed on membrane surfaces was investigated under two feedwater conditions: raw seawater and deep bed filtration-treated seawater. As a result of chlorination, the structure of the biofilm community on the microfiltration/ultrafiltration and reverse osmosis membrane coupons shifted significantly at the genus level. However, the total bacterial population was not reduced under the two feedwater conditions. This failure to control the biofilm was attributed to the adaptation and survival of selected bacteria under chlorine stress. Phaeobacter caeruleus, isolated from the biofilm, was examined as a representative chlorine-resistant biofilm-forming bacterium. The number of viable P. caeruleus was significantly reduced (as much as 99.8%) after ultraviolet (UV) disinfection. The results indicated that additional disinfection by UV irradiation can inactivate chlorine-resistant bacteria. Therefore, tandem chlorination-UV disinfection may enhance the efficiency of biofouling control in seawater reverse osmosis processes. The synergistic effects of tandem chlorination-UV irradiation on the marine biofilm community should be investigated in future studies.}, } @article {pmid29948114, year = {2018}, author = {Wang, X and Zhao, X and Wang, H and Huang, X and Duan, X and Gu, Y and Lambert, N and Zhang, K and Kou, Z and Xie, J}, title = {Mycobacterium tuberculosis toxin Rv2872 is an RNase involved in vancomycin stress response and biofilm development.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {16}, pages = {7123-7133}, doi = {10.1007/s00253-018-9132-0}, pmid = {29948114}, issn = {1432-0614}, support = {81371851//National Natural Science Foundation of China/ ; 81071316//National Natural Science Foundation of China/ ; 81271882//National Natural Science Foundation of China/ ; }, mesh = {*Biofilms ; Drug Resistance, Bacterial/genetics ; Mycobacterium tuberculosis/drug effects/*enzymology/genetics ; Ribonucleases/*metabolism ; Stress, Physiological/*genetics ; Vancomycin/pharmacology ; }, abstract = {Bacterial toxin-antitoxin (TA) systems are emerging important regulators of multiple cellular physiological events and candidates for novel antibiotic targets. To explore the role of Mycobacterium tuberculosis function, unknown toxin gene Rv2872 was heterologously expressed in Mycobacterium smegmatis (MS_Rv2872). Upon induction, MS_Rv2872 phenotype differed significantly from the control, such as increased vancomycin resistance, retarded growth, cell wall, and biofilm structure. This phenotype change might result from the RNase activity of Rv2872 as purified Rv2872 toxin protein can cleave the products of several key genes involved in abovementioned phenotypes. In summary, toxin Rv2872 was firstly reported to be a endonuclease involved in antibiotic stress responses, cell wall structure, and biofilm development.}, } @article {pmid29948009, year = {2018}, author = {Gupta, P and Mankere, B and Chekkoora Keloth, S and Tuteja, U and Chelvam, KT}, title = {Generation and In Vivo Characterization of Tn5-Induced Biofilm Mutants of Vibrio cholerae O139.}, journal = {Current microbiology}, volume = {75}, number = {10}, pages = {1324-1333}, pmid = {29948009}, issn = {1432-0991}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; DNA Transposable Elements ; Gene Expression Regulation, Bacterial ; Humans ; Intestines/microbiology ; Mice ; Mice, Inbred BALB C ; *Mutagenesis, Insertional ; Vibrio cholerae O139/*genetics/growth & development/physiology ; }, abstract = {The Gram-negative bacterium Vibrio cholerae is a unique pathogen with an ability to colonize human intestine as well as outside environments. The biofilm, an organized polymeric structure produced by this bacterium known to be a significant factor for the survival and persistence in hostile conditions. However, the direct role of biofilm formation by this bacterium in environmental persistence, in vivo colonization, and pathogenesis remains unexplored. In this study, we have generated biofilm-altered Tn5 mutants of V. cholerae O139 and evaluated their in vivo colonization ability on mouse model. These Tn5 mutants were found to harbor an independent, single Tn5 insertion in their genome. The DNA sequence analysis revealed that genomic region wherein Tn5 insertion occurred is identified to be involved in functions like LPS biosynthesis, efflux transporters, motility, purine metabolism, stringent response, VPS synthesis, and a hypothetical protein of unknown function. In single-strain infection with the planktonic culture, the biofilm-altered as well as the biofilm intermediate mutants were found to be more or less similar in their intestinal colonization ability, however infection with their biofilm form, a marked difference was observed between the biofilm deficient and other biofilm forming strains. Further, in the competition experiments, biofilm deficient and proficient mutants were found reduced in their colonization ability and outcompeted by their parent strain. In conclusion, biofilm formation in V. cholerae O139 is a genetically complex process and the controlled and regulated production of biofilm appeared to be necessary for its efficient colonization of mouse intestine.}, } @article {pmid29945306, year = {2018}, author = {Zhang, J and Xu, LL and Gan, D and Zhang, X}, title = {In Vitro Study of Bacteriophage AB3 Endolysin LysAB3 Activity Against Acinetobacter baumannii Biofilm and Biofilm-Bound A. baumannii.}, journal = {Clinical laboratory}, volume = {64}, number = {6}, pages = {1021-1030}, doi = {10.7754/Clin.Lab.2018.180342}, pmid = {29945306}, issn = {1433-6510}, mesh = {Acinetobacter baumannii/drug effects/*physiology/virology ; Anti-Bacterial Agents/pharmacology ; Bacteriophages/genetics/*metabolism/physiology ; Biofilms/drug effects/*growth & development ; Endopeptidases/genetics/*metabolism ; Escherichia coli/genetics ; Host-Pathogen Interactions/drug effects ; Humans ; Microbial Sensitivity Tests ; Recombinant Proteins/metabolism/pharmacology ; }, abstract = {BACKGROUND: The increase in the prevalence of drug-resistant Acinetobacter baumannii is a serious public health concern, which is closely linked to the formation of biofilm. It is reported that the bacteriophage and its endolysin have a good ability to degrade biofilms. The goals of this study were to compare the ability of A. baumannii bacteriophage AB3, its endolysin AB3, and three antibiotics to degrade A. baumannii biofilm and biofilm-bound A. baumannii and to understand the antibacterial mechanism of LysAB3.

METHODS: The 558-bp sequence of the LysAB3 gene was amplified by polymerase chain reaction (PCR); the fragment was cloned into pET28a (+) to construct the recombinant plasmid pET28a-LysAB3, which was then expressed in E. coli BL21 (DE3) to obtain the LysAB3. Differences in A. baumannii biofilm and biofilm-bound A. baumannii after treatment with bacteriophage AB3, LysAB3 or three antibiotics were examined using the crystal violet staining method and an MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) assay. Changes in biofilm morphology and thickness in each treatment group were observed by laser scanning confocal microscopy. In addition, a LysAB3 construct with the amphiphilic peptide structural region removed (LysAB3-D) was assessed for its antibacterial activity.

RESULTS: After 24-hour treatment with either bacteriophage AB3 and its LysAB3, A. baumannii biofilms were significantly degraded, and the number of viable biofilm-bound A. baumannii were also significantly decreased. After removing the amphiphilic peptide structure motif from LysAB3, the antibacterial activity decreased from 95.8% to 33.3%.

CONCLUSIONS: Thus, LysAB3 can effectively degrade A. baumannii biofilm and biofilm-bound A. baumannii in vitro. The antibacterial mechanism of LysAB3 may be associated with the ability of the amphiphilic peptide structural region to enhance the permeability of cytoplasmic membrane of A. baumannii by degradation of bacterial wall peptidoglycan.}, } @article {pmid29939885, year = {2018}, author = {Borges, EL and Frison, SS and Honorato-Sampaio, K and Guedes, ACM and Lima, VLAN and Oliveira, OMM and Ferraz, AF and Tyrone, AC}, title = {Effect of Polyhexamethylene Biguanide Solution on Bacterial Load and Biofilm in Venous Leg Ulcers: A Randomized Controlled Trial.}, journal = {Journal of wound, ostomy, and continence nursing : official publication of The Wound, Ostomy and Continence Nurses Society}, volume = {45}, number = {5}, pages = {425-431}, doi = {10.1097/WON.0000000000000455}, pmid = {29939885}, issn = {1528-3976}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Infective Agents, Local/pharmacology/therapeutic use ; Bacterial Load/*statistics & numerical data ; Biguanides/*pharmacology/therapeutic use ; Biofilms/drug effects ; Brazil ; Female ; Humans ; Leg Ulcer/*drug therapy ; Male ; Middle Aged ; Therapeutic Irrigation/methods/standards ; Varicose Ulcer/drug therapy ; Wounds and Injuries/drug therapy ; }, abstract = {PURPOSE: The purpose of this study was to investigate the effect of polyhexamethylene biguanide (PHMB) solution as a wound cleanser on bacterial load and bacterial biofilm in venous leg ulcers.

DESIGN: Randomized controlled trial.

SUBJECTS AND SETTING: The target population was adults attending the dermatology outpatient clinic of the Clinical Hospital of the Federal University of Minas Gerais, Brazil. The sample comprised 44 patients with venous leg ulcers recruited over a 6-month period.

METHODS: Participants were divided into 2 groups: the intervention group had their wounds cleansed with PHMB, and the control group had their wound cleansed with a 0.9% saline solution. Tissue fragments of the wounds were collected for bacteriological analysis; transmission electron microscopy was used to identify the presence of biofilm.

RESULTS: The bacterial load was reduced in both groups compared to baseline values; no significant difference was found when groups were compared. Correlation analysis between wound duration (months), wound area (cm²), necrosis (%), variables, and bacterial count (colony forming units [CFUs]/g) after cleansing showed a significant relationship between area of the wound and CFUs/g (P = .0070, r = 0.51). Transmission electron microscopy revealed the presence of bacterial biofilm in the wounds after cleansing with both solutions.

CONCLUSIONS: The results of this study indicate that both PHMB and saline solution are effective in reducing the bacterial load in venous leg ulcers. However, bacterial biofilm was present after cleansing with both solutions. These findings provide important evidence regarding effectiveness of 2 common wound cleansers on bacterial presence in wounds.}, } @article {pmid29938072, year = {2018}, author = {Deschaine, BM and Heysel, AR and Lenhart, BA and Murphy, HA}, title = {Biofilm formation and toxin production provide a fitness advantage in mixed colonies of environmental yeast isolates.}, journal = {Ecology and evolution}, volume = {8}, number = {11}, pages = {5541-5550}, pmid = {29938072}, issn = {2045-7758}, abstract = {Microbes can engage in social interactions ranging from cooperation to warfare. Biofilms are structured, cooperative microbial communities. Like all cooperative communities, they are susceptible to invasion by selfish individuals who benefit without contributing. However, biofilms are pervasive and ancient, representing the first fossilized life. One hypothesis for the stability of biofilms is spatial structure: Segregated patches of related cooperative cells are able to outcompete unrelated cells. These dynamics have been explored computationally and in bacteria; however, their relevance to eukaryotic microbes remains an open question. The complexity of eukaryotic cell signaling and communication suggests the possibility of different social dynamics. Using the tractable model yeast, Saccharomyces cerevisiae, which can form biofilms, we investigate the interactions of environmental isolates with different social phenotypes. We find that biofilm strains spatially exclude nonbiofilm strains and that biofilm spatial structure confers a consistent and robust fitness advantage in direct competition. Furthermore, biofilms may protect against killer toxin, a warfare phenotype. During biofilm formation, cells are susceptible to toxin from nearby competitors; however, increased spatial use may provide an escape from toxin producers. Our results suggest that yeast biofilms represent a competitive strategy and that principles elucidated for the evolution and stability of bacterial biofilms may apply to more complex eukaryotes.}, } @article {pmid29936108, year = {2018}, author = {Hu, WS and Kim, H and Koo, OK}, title = {Molecular genotyping, biofilm formation and antibiotic resistance of enterotoxigenic Clostridium perfringens isolated from meat supplied to school cafeterias in South Korea.}, journal = {Anaerobe}, volume = {52}, number = {}, pages = {115-121}, doi = {10.1016/j.anaerobe.2018.06.011}, pmid = {29936108}, issn = {1095-8274}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Toxins ; Biofilms/*drug effects ; Chickens ; Clostridium Infections/microbiology/*veterinary ; Clostridium perfringens/drug effects/genetics/*isolation & purification/physiology ; *Drug Resistance, Bacterial ; Ducks ; Food Contamination/*analysis ; Foodborne Diseases/*microbiology ; Genotype ; Humans ; Meat/*microbiology ; Republic of Korea ; Schools/statistics & numerical data ; Swine ; }, abstract = {Clostridium perfringens is one of the leading causes of food poisoning worldwide. The aims of this study were to investigate the presence of C. perfringens in food supplied to school cafeterias, to assess the presence of toxin genes in the isolates, and to investigate the biofilm formation and antibiotic susceptibility of the isolates. A total of 30 C. perfringens strains (12.9%) from 232 samples of beef, pork, chicken, and duck meat were isolated. Toxin genes, including cpa, cpe, cpb2, and netB, were detected, while the cpb, etx, iap and tpeL genes were absent. Biofilm formation was analyzed, and all the isolates were able to form biofilm. Antibiotic resistance was observed against penicillin (97%), lincomycin (20%), bacitracin (97%), oxytetracycline (73%), trimethoprim (7%), gentamicin (10%), tetracycline (93%), erythromycin (83%), ampicillin (100%), amikacin (7%), and streptomycin (3%). In conclusion, the results showed that students are exposed to a potentially high risk of food poisoning by C. perfringens; therefore, precaution is required for these types of catering services.}, } @article {pmid29933729, year = {2018}, author = {Şahin, R and Kaleli, İ}, title = {[Comparison of genotypic and phenotypic characteristics in biofilm production of Staphylococcus aureus isolates].}, journal = {Mikrobiyoloji bulteni}, volume = {52}, number = {2}, pages = {111-112}, doi = {10.5578/mb.66773}, pmid = {29933729}, issn = {0374-9096}, mesh = {*Biofilms ; Genes, Bacterial/genetics ; *Genotype ; *Phenotype ; *Staphylococcus aureus/pathogenicity/physiology ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus which is an important pathogen, is known to have several virulence factors. The pathogenicity of S.aureus isolates are related with features like adherence, various toxins, enzymes, structural and extracellular factors. Slime factor and biofilm formation are also the pathogenicity factors of the bacteria. Biofilm formation is usually associated with chronic infections and has become a subject of interest in a wide area of research. Biofilm is an adherent structure formed by bacteria encased within a matrix produced on natural body surfaces or medical devices. As the biofilm producing S.aureus isolates are more resistant to antibiotics and and their biofilms prevent phagocytosis, the treatment of infections caused by biofilm positive S.aureus isolates become difficult. The icaADBC locus and some proteins have provento be responsible for the formation of S.aureus type biofilm. The aim of this study was to investigate the relationship between the genotypic and phenotypic detection methods of biofilm formation with icaA, icaD and bap genes and phenotype expressions which are responsible for the formation of biofilm in S.aureus isolates. One hundred seventy five S.aureus isolates from various clinical specimens were included in the study. For the phenotypic detection of biofilm producing isolates Congo red agar (CRA) medium and microplate method were used. The biofilm-producing strain Staphylococcus epidermidis ATCC 35984 and S. epidermidis ATCC 12228 were used as positive and negative controls, respectively. One hundred fifty two S.aureus biofilm producing isolates were detected at least by either Congo Red agar or microplate method and all isolates were screened for icaA, icaD and bap genes by PCR. The production of polysaccharide intracellular adhesins /poly-N-acetyl-beta-1-6-glucosamine (PIA/PNAG) was also investigated in S.aureus isolates. For the detection of PIA/PNAG chemiluminescence dot-blot method was used. According to the phenotypic evaluations based on colony morphologies in CRA medium, biofilm formation were found as negative in 101 of 175 isolates (57.7%), while biofilm formation were positive in 74 (42.3%) of the isolates. As a result of quantitative evaluation by microplate method based on absorbance measurement, biofilm production was determined as negative in 34 (19.4%) specimens, moderate in 112 (64.0%) specimens and strong in 29 (16.6%) specimens. Microplate and CRA methods were incompatible with each other when compared for their biofilm production determination (p< 0.001). Among the 152 clinical isolates used to determine the presence of icaA and icaD genes responsible for the formation of biofilms, the genes were detected in 136 (89.5%) of the isolates and in the S.epidermidis ATCC 35984 strain used as a positive control. icaA and icaD genes were not detected in sixteen of the 152 (10.5%) clinical isolates and in the S.epidermidis ATCC 12228 strain used as a negative control. A weak-moderate correlation was found between icaA and icaD genes and biofilm production determined in CRA medium. A good correlation was found between icaA and icaD genes and biofilm production detected in microplate method. bap gene was determined in only one of the 152 clinical S.aureus isolates studied and in S.aureus V329 strain used as positive control. For the detection of PIA/PNAG which was synthesized by icaADBC genes, 50 clinical S.aureus isolates were used. PNAG production was determined in 42 isolates with positive icaA and icaD genes by the chemiluminescence dot-blot method, and no PNAG production was determined among eight isolates with negative ica genes. As a result, it was found that the microplate method was more sensitive and reliable for the phenotypic determination of biofilm formation in S.aureus isolates, high level of biofilm formation among clinical S.aureus isolates (about 80%), the role of icaA and icaD genes and products (PIA/PNAG) in biofilm production was determined.}, } @article {pmid29933190, year = {2018}, author = {Tang, CC and Tian, Y and He, ZW and Zuo, W and Zhang, J}, title = {Performance and mechanism of a novel algal-bacterial symbiosis system based on sequencing batch suspended biofilm reactor treating domestic wastewater.}, journal = {Bioresource technology}, volume = {265}, number = {}, pages = {422-431}, doi = {10.1016/j.biortech.2018.06.033}, pmid = {29933190}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Chlorella ; Chlorophyll ; Chlorophyll A ; Nitrogen ; Phosphorus ; *Symbiosis ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {A novel algal-bacterial symbiosis system based on sequencing batch suspended biofilm reactor (A-SBSBR) was developed for simultaneously enhanced nitrogen (N) and phosphorus (P) removal from domestic wastewater. Results showed that the total N (TN) and P (TP) removal efficiencies in A-SBSBR increased to 69.91% and 94.78%, respectively. The mechanism analysis indicated that TN removal mainly occurred at non-aeration stage, and TP removal happened during the whole cycle in A-SBSBR. Compared to control SBSBR, TN removal by denitrification and anabolism and TP removal by anabolism in A-SBSBR increased by 12.70%, 7.64% and 50.13%, respectively. The Chlorophyll a accumulation in biofilm increased to 4.80 ± 0.08 mg/g. Algae related to Chlorella and Scenedesmus and bacteria related to Flavobacterium, Micropruina and Comamonadaceae were enriched in A-SBSBR and responsible for the enhanced nutrients removal effect. This study may provide a new solution to achieve nutrients removal enhancement from wastewater.}, } @article {pmid29930547, year = {2018}, author = {Barriuso, J and Martínez, MJ}, title = {In Silico Analysis of the Quorum Sensing Metagenome in Environmental Biofilm Samples.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1243}, pmid = {29930547}, issn = {1664-302X}, abstract = {Quorum sensing (QS) is a sophisticated cell to cell signaling mechanism mediated by small diffusible molecules called "autoinducers." This phenomenon is well studied in bacteria, where different QS systems are described that differ between Gram-negative and Gram-positive bacteria. However, a common system to these groups was discovered, the autoinducer 2. QS has implications in biofilm formation, where the application of metagenomic techniques to study these phenomena may be useful to understand the communication networks established by the different components of the community, and to discover new targets for microbial control. Here we present an in silico screening of QS proteins in all publicly available biofilm metagenomes from the JGI database. We performed sequence, conserved motifs, phylogenetic, and three-dimensional structure analyses of the candidates, resulting in an effective strategy to search QS proteins in metagenomes sequences. The number of QS proteins present in each sample, and its phylogenetic affiliation, was clearly related to the bacterial diversity and the origin of the biofilm. The samples isolated from natural habitats presented clear differences with those from artificial habitats. Interesting findings have been made in the abundance of LuxR-like proteins finding an unbalanced ratio between the synthases and the receptor proteins in Bacteroidetes bacteria, pointing out the existence of "cheaters" in this group. Moreover, we have shown the presence of the LuxI/R QS system in bacteria from the Nitrospira taxonomic group. Finally, some undescribed proteins from the HdtS family have been found in Gamma-proteobacteria.}, } @article {pmid29930327, year = {2018}, author = {Ashrafi, M and Novak-Frazer, L and Bates, M and Baguneid, M and Alonso-Rasgado, T and Xia, G and Rautemaa-Richardson, R and Bayat, A}, title = {Validation of biofilm formation on human skin wound models and demonstration of clinically translatable bacteria-specific volatile signatures.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {9431}, pmid = {29930327}, issn = {2045-2322}, support = {//Wellcome Trust/United Kingdom ; /BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adult ; Bacteriological Techniques/*methods ; *Biofilms ; Female ; Humans ; Male ; Middle Aged ; Pseudomonas aeruginosa/metabolism/pathogenicity/physiology ; Skin/*microbiology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/metabolism/pathogenicity/physiology ; Volatile Organic Compounds/analysis/*metabolism ; Wound Infection/*microbiology ; }, abstract = {Biofilms are major contributors to delayed wound healing and there is a need for clinically relevant experimental models to assess theranostics. Microorganisms release volatile organic compounds (VOCs) and the ability to identify these in infected cutaneous wounds could lead to efficient non-invasive diagnosis. The aims here were to develop and assess bacterial biofilm formation and identify their VOC profiles in an in vitro model and validate in human ex vivo incisional and excisional cutaneous wound models. Biofilm development was assessed using multiple microscopy techniques with biofilm-forming deficient controls and quantified using metabolic and biomass assays; and VOC production measured by gas chromatography-mass spectrometry. The production of most VOCs was affected by biofilm development and model used. Some VOCs were specific either for planktonic or biofilm growth. The relative abundance of some VOCs was significantly increased or decreased by biofilm growth phase (P < 0.05). Some Staphylococcus aureus and Pseudomonas aeruginosa VOCs correlated with biofilm metabolic activity and biomass (R ≤ -0.5; ≥0.5). We present for the first time bacterial biofilm formation in human ex vivo cutaneous wound models and their specific VOC profiles. These models provide a vehicle for human skin-relevant biofilm studies and VOC detection has potential clinical translatability in efficient non-invasive diagnosis of wound infection.}, } @article {pmid29929311, year = {2018}, author = {Gulotta, D and Villa, F and Cappitelli, F and Toniolo, L}, title = {Biofilm colonization of metamorphic lithotypes of a renaissance cathedral exposed to urban atmosphere.}, journal = {The Science of the total environment}, volume = {639}, number = {}, pages = {1480-1490}, doi = {10.1016/j.scitotenv.2018.05.277}, pmid = {29929311}, issn = {1879-1026}, mesh = {Atmosphere ; Biofilms/*growth & development ; *Construction Materials ; *Ecosystem ; Italy ; Weather ; }, abstract = {Stone architectural heritage exposed outdoor represents a challenging habitat for biological growths; nevertheless, biocolonization on heritage structure is ubiquitous and represents a major mechanism of alteration. However, the identification of specific microorganisms with known reactivity towards the stone substrate does not necessarily imply that a biodeterioration process is in progress and, in specific conditions, bioprotection effects have been highlighted as a result of colonization. The main objective of the present research is to evaluate the biofilm formation on different lithotypes exposed to similar environmental polluted conditions, and to investigate whether the presence of subaerial biofilms can be associated to an increased magnitude of deterioration of the colonized surfaces with respect to the not colonized ones. In particular, the research examines the extensive biological colonization of the stone surfaces of the façade of the Cathedral of Monza (Italy). Four metamorphic stones widely used in the façade and showing rather different compositional, mineralogical and microstructural features were studied. The state of conservation of the stones was characterized under the mineralogical and compositional point of view by X-ray diffraction and Fourier Transformed infrared analysis. The microstructure of colonized substrates and of reference not colonized ones was studied by means of optical and electron microscopy, to comparatively evaluate the damage extent and weathering patterns in both conservative conditions. The structure and the architecture of biofilms growing on different lithic surfaces were investigated by CLSM in both fluorescence and reflection modes. Captured images were analyzed for 3D reconstructions of biofilm samples. The biovolumes were also calculated to estimate the total biomass. The results indicate that the four lithotypes showed different colonization extents. However, even in presence of extensive biological growth, chemical-physical deterioration mechanisms caused by environmental exposure were largely responsible for deterioration. A relationship between compositional and surface morphological features and biocolonization was also observed.}, } @article {pmid29928943, year = {2018}, author = {Shi, H and Zhou, X and Zou, W and Wang, Y and Lei, C and Xiang, R and Zhou, L and Liu, B and Zhang, A and Wang, H}, title = {Co-occurrence of biofilm formation and quinolone resistance in Salmonella enterica serotype typhimurium carrying an IncHI2-type oqxAB-positive plasmid.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {68-73}, doi = {10.1016/j.micpath.2018.06.006}, pmid = {29928943}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Chickens/microbiology ; Conjugation, Genetic/genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Gene Transfer, Horizontal/genetics ; Microbial Sensitivity Tests ; Plasmids/*genetics ; Poultry Diseases/microbiology ; Quinolones/*pharmacology ; Salmonella typhimurium/*drug effects/isolation & purification ; }, abstract = {The objective of this study was to investigate the co-occurrence of biofilms and quinolone resistance in Salmonella enterica serotype Typhimurium mediated by IncHI2-type oqxAB-positive plasmids. Among the 40 Salmonella strains, we found that 27 isolates formed biofilms and displayed identical multidrug-resistance profiles to ciprofloxacin, doxycycline, sulfamethoxazole-trimethoprim, ampicillin and streptomycin, based on biofilm formation assays and antimicrobial susceptibility testing. In particular, a single S. Typhimurium isolate named SC523 produced the thickest biofilms and exhibited the highest-level resistance (MIC = 8 μg/mL) to ciprofloxacin compared to those of the other isolates. The detection of known plasmid-mediated quinolone resistance (PMQR) genes and point mutations in the quinolone resistance-determining region (QRDR) by PCR assay showed that oqxAB genes were present in 27 biofilm-positive isolates. Conjugation experiments, S1-pulse-field gel electrophoresis and biofilm formation assays demonstrated that the conjugative plasmid that encoded biofilms and quinolone resistance in Salmonella SC523 could be transferred to a recipient with a frequency of 4.7 × 10[-3] per recipient cell. The results of PCR-based replicon typing (PBRT) showed that the IncHI2-type plasmids accounted for 100% of the biofilm-oqxAB-positive isolates and transconjugants. The sequence analysis of Salmonella SC523 confirmed that the oqxAB cassette and fourteen DNA transfer genes in the IncHI2-type oqxAB-positive conjugative plasmid were genetically responsible for the phenotypic quinolone resistance and biofilm formation. The conclusion is that the IncHI2-type plasmid in S. Typhimurium isolate from chicken farm was identified and sequenced, which contained oqxAB and tra/trh and encoded quinolone resistance and biofilms, and could be transferred to recipients through conjugation. Notably, the prevalence of IncHI2-type biofilm-oqxAB-positive plasmids in animal-origin Salmonella poses a threat to public health, as these Salmonella from poultry farms show a decreased susceptibility to quinolones and could spread to humans.}, } @article {pmid29928267, year = {2018}, author = {Oh, E and Andrews, KJ and Jeon, B}, title = {Enhanced Biofilm Formation by Ferrous and Ferric Iron Through Oxidative Stress in Campylobacter jejuni.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1204}, pmid = {29928267}, issn = {1664-302X}, abstract = {Campylobacter is a leading foodborne pathogen worldwide. Biofilm formation is an important survival mechanism that sustains the viability of Campylobacter under harsh stress conditions. Iron affects biofilm formation in some other bacteria; however, the effect of iron on biofilm formation has not been investigated in Campylobacter. In this study, we discovered that ferrous (Fe[2+]) and ferric (Fe[3+]) iron stimulated biofilm formation in Campylobacter jejuni. The sequestration of iron with an iron chelator prevented the iron-mediated biofilm stimulation. The level of total reactive oxygen species (ROS) in biofilms was increased by iron. However, the supplementation with an antioxidant prevented the total ROS level from being increased in biofilms by iron and also inhibited iron-mediated biofilm stimulation in C. jejuni. This suggests that iron promotes biofilm formation through oxidative stress. Based on the results of fluorescence microscopic analysis, Fe[2+] and Fe[3+] enhanced both microcolony formation and biofilm maturation. The levels of extracellular DNA and polysaccharides in biofilms were increased by iron supplementation. The effect of iron on biofilm formation was also investigated with 70 C. jejuni isolates from raw chicken. Regardless of the inherent levels of biofilm formation, iron stimulated biofilm formation in all tested strains; however, there were strain variations in iron concentrations affecting biofilm formation. The biofilm formation of 92.9% (65 of 70) strains was enhanced by either 40 μM Fe[2+] or 20 μM Fe[3+] or both (the iron concentrations that enhanced biofilm formation in C. jejuni NCTC 11168), whereas different iron concentrations were required to promote biofilms in the rest of the strains. The findings in this study showed that Fe[2+] and Fe[3+] contributed to the stimulation of biofilm formation in C. jejuni through oxidative stress.}, } @article {pmid29928049, year = {2018}, author = {Pletzer, D and Mansour, SC and Hancock, REW}, title = {Synergy between conventional antibiotics and anti-biofilm peptides in a murine, sub-cutaneous abscess model caused by recalcitrant ESKAPE pathogens.}, journal = {PLoS pathogens}, volume = {14}, number = {6}, pages = {e1007084}, pmid = {29928049}, issn = {1553-7374}, support = {FDN-154287//Canadian Institutes for Health Research/International ; R33 AI098701/AI/NIAID NIH HHS/United States ; }, mesh = {Abscess/*drug therapy/microbiology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Female ; Gram-Negative Bacteria/*pathogenicity ; Gram-Positive Bacteria/*pathogenicity ; Injections, Subcutaneous ; Mice ; Microbial Viability ; Peptide Fragments/*pharmacology ; Skin Diseases, Bacterial/*drug therapy/microbiology ; }, abstract = {With the antibiotic development pipeline running dry, many fear that we might soon run out of treatment options. High-density infections are particularly difficult to treat due to their adaptive multidrug-resistance and currently there are no therapies that adequately address this important issue. Here, a large-scale in vivo study was performed to enhance the activity of antibiotics to treat high-density infections caused by multidrug-resistant Gram-positive and Gram-negative bacteria. It was shown that synthetic peptides can be used in conjunction with the antibiotics ciprofloxacin, meropenem, erythromycin, gentamicin, and vancomycin to improve the treatment outcome of murine cutaneous abscesses caused by clinical hard-to-treat pathogens including all ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter cloacae) pathogens and Escherichia coli. Promisingly, combination treatment often showed synergistic effects that significantly reduced abscess sizes and/or improved clearance of bacterial isolates from the infection site, regardless of the antibiotic mode of action. In vitro data suggest that the mechanisms of peptide action in vivo include enhancement of antibiotic penetration and potential disruption of the stringent stress response.}, } @article {pmid29926921, year = {2018}, author = {Larue, AE and Swider, P and Duru, P and Daviaud, D and Quintard, M and Davit, Y}, title = {Quantitative 3D comparison of biofilm imaged by X-ray micro-tomography and two-photon laser scanning microscopy.}, journal = {Journal of microscopy}, volume = {271}, number = {3}, pages = {302-314}, doi = {10.1111/jmi.12718}, pmid = {29926921}, issn = {1365-2818}, mesh = {*Biofilms ; Contrast Media ; Imaging, Three-Dimensional/*methods ; Microscopy, Confocal/*methods ; Porosity ; Pseudomonas aeruginosa/physiology ; X-Ray Microtomography/*methods ; }, abstract = {Optical imaging techniques for biofilm observation, like laser scanning microscopy, are not applicable when investigating biofilm formation in opaque porous media. X-ray micro-tomography (X-ray CMT) might be an alternative but it finds limitations in similarity of X-ray absorption coefficients for the biofilm and aqueous phases. To overcome this difficulty, barium sulphate was used in Davit et al. (2011) to enable high-resolution 3D imaging of biofilm via X-ray CMT. However, this approach lacks comparison with well-established imaging methods, which are known to capture the fine structures of biofilms, as well as uncertainty quantification. Here, we compare two-photon laser scanning microscopy (TPLSM) images of Pseudomonas Aeruginosa biofilm grown in glass capillaries against X-ray CMT using an improved protocol where barium sulphate is combined with low-gelling temperature agarose to avoid sedimentation. Calibrated phantoms consisting of mono-dispersed fluorescent and X-ray absorbent beads were used to evaluate the uncertainty associated with our protocol along with three different segmentation techniques, namely hysteresis, watershed and region growing, to determine the bias relative to image binarization. Metrics such as volume, 3D surface area and thickness were measured and comparison of both imaging modalities shows that X-ray CMT of biofilm using our protocol yields an accuracy that is comparable and even better in certain respects than TPLSM, even in a nonporous system that is largely favourable to TPLSM.}, } @article {pmid29925708, year = {2018}, author = {Gomez, GF and Huang, R and Eckert, G and Gregory, RL}, title = {Effect of phototherapy on the metabolism of Streptococcus mutans biofilm based on a colorimetric tetrazolium assay.}, journal = {Journal of oral science}, volume = {60}, number = {2}, pages = {242-246}, doi = {10.2334/josnusd.17-0203}, pmid = {29925708}, issn = {1880-4926}, mesh = {*Biofilms ; Colorimetry/*methods ; Humans ; *Phototherapy ; Streptococcus mutans/*metabolism/*radiation effects ; Tetrazolium Salts/*chemistry ; }, abstract = {The aim of this in vitro study was to determine the effect of violet-blue light on the metabolic activity of early Streptococcus mutans biofilm, reincubated at 0, 2, and 6 h after 5 min of violet-blue light treatment. S. mutans UA159 biofilm cells were cultured for 12 to 16 h in microtiter plates with Tryptic Soy broth (TSB) or TSB with 1% sucrose (TSBS) and irradiated with violet-blue light for 5 min. After irradiation, the plates were reincubated at 37°C for 0, 2, or 6 h in 5% CO2. Colorimetric tetrazolium salt reduction assay was used to investigate bacterial metabolic activity. Mixed model ANOVA was used to find the difference between the violet-blue light treated and nontreated groups. Bacterial metabolic activity was significantly lower in the violet-blue light group for TSB than in the nontreated group (P < 0.0001) regardless of recovery time. However, the differences between metabolic activity in the treated groups without sucrose decreased over time. For TSBS, metabolic activity was significantly lower with violet-blue light at 0 and 2 h. Violet-blue light inhibited the metabolic activity of S. mutans biofilm cells in the light-treated group. This finding may present a unique treatment method for patients with active caries.}, } @article {pmid29924909, year = {2018}, author = {Maszewska, A and Zygmunt, M and Grzejdziak, I and Różalski, A}, title = {Use of polyvalent bacteriophages to combat biofilm of Proteus mirabilis causing catheter-associated urinary tract infections.}, journal = {Journal of applied microbiology}, volume = {125}, number = {5}, pages = {1253-1265}, doi = {10.1111/jam.14026}, pmid = {29924909}, issn = {1365-2672}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; *Bacteriophages/chemistry/pathogenicity ; Biofilms/*drug effects ; Catheter-Related Infections/*microbiology ; Humans ; *Proteus mirabilis/drug effects/virology ; Urinary Tract Infections/*microbiology ; }, abstract = {AIMS: Catheter-associated urinary tract infections (CAUTI) caused by Proteus mirabilis are very difficult to treat due to the ability of biofilm formation and drug resistance of these bacteria. The aim of this study was to assess the antibiofilm activity of phages and develop phage cocktail to combat biofilm of P. mirabilis strains.

METHODS AND RESULTS: Planktonic forms and biofilms of 50 tested uropathogenic P. mirabilis strains showed different sensitivity to 13 phages used. Phages 39APmC32, 65APm2833 and 72APm5211 presenting strong antibiofilm activity were selected as cocktail components. The antibiofilm activity of phage cocktails was similar or slightly higher than that of the most active phage. A three-phage cocktail inhibited biofilm formation and destroyed biofilms of the same number of strains or 2-3 strains more compared to a single phage. The components of the three-phage cocktail did not block each other's activity.

CONCLUSIONS: The potential of developed anti-P. mirabilis phage cocktail as an antibiofilm agent was proved.

In this study, three broad host range phages presenting strong anti-P. mirabilis biofilm activity were selected. Additionally, high stability of these viruses makes them a useful tool for controlling the biofilms.}, } @article {pmid29923229, year = {2018}, author = {Tan, L and Li, J and Liu, X and Cui, Z and Yang, X and Zhu, S and Li, Z and Yuan, X and Zheng, Y and Yeung, KWK and Pan, H and Wang, X and Wu, S}, title = {Rapid Biofilm Eradication on Bone Implants Using Red Phosphorus and Near-Infrared Light.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {30}, number = {31}, pages = {e1801808}, doi = {10.1002/adma.201801808}, pmid = {29923229}, issn = {1521-4095}, mesh = {Animals ; Biofilms/drug effects/*radiation effects ; Bone Substitutes/*chemistry ; Cell Line ; Cell Survival/drug effects/radiation effects ; Core Binding Factor Alpha 1 Subunit/genetics/metabolism ; *Infrared Rays ; Mice ; Osteoblasts/cytology/metabolism ; Peptides/chemistry ; Phosphorus/*chemistry/pharmacology ; Phototherapy ; Prostheses and Implants ; Singlet Oxygen/chemistry/metabolism ; Staphylococcus aureus/physiology ; Temperature ; Titanium/chemistry ; }, abstract = {Bone-implant-associated infections are common after orthopedic surgery due to impaired host immune response around the implants. In particular, when a biofilm develops, the immune system and antibiotic treatment find it difficult to eradicate, which sometimes requires a second operation to replace the infected implants. Most strategies have been designed to prevent biofilms from forming on the surface of bone implants, but these strategies cannot eliminate the biofilm when it has been established in vivo. To address this issue, a nonsurgical, noninvasive treatment for biofilm infection must be developed. Herein, a red-phosphorus-IR780-arginine-glycine-aspartic-acid-cysteine coating on titanium bone implants is prepared. The red phosphorus has great biocompatibility and exhibits efficient photothermal ability. The temperature sensitivity of Staphylococcus aureus biofilm is enhanced in the presence of singlet oxygen ([1] O2) produced by IR780. Without damaging the normal tissue, the biofilm can be eradicated through a safe near-infrared (808 nm) photothermal therapy at 50 °C in vitro and in vivo. This approach reaches an antibacterial efficiency of 96.2% in vivo with 10 min of irradiation at 50 °C. Meanwhile, arginine-glycine-aspartic-acid-cysteine decorated on the surface of the implant can improve the cell adhesion, proliferation, and osteogenic differentiation.}, } @article {pmid29923129, year = {2019}, author = {Dvořáčková, M and Růžička, F and Benešík, M and Pantůček, R and Dvořáková-Heroldová, M}, title = {Antimicrobial effect of commercial phage preparation Stafal® on biofilm and planktonic forms of methicillin-resistant Staphylococcus aureus.}, journal = {Folia microbiologica}, volume = {64}, number = {1}, pages = {121-126}, pmid = {29923129}, issn = {1874-9356}, support = {16-29916A//Ministerstvo Zdravotnictví Ceské Republiky/ ; }, mesh = {*Anti-Infective Agents ; Bacteriological Techniques ; *Biofilms ; Colony Count, Microbial ; Humans ; Methicillin-Resistant Staphylococcus aureus/growth & development/isolation & purification/*virology ; Microbial Viability ; Staphylococcal Infections/*microbiology ; Staphylococcus Phages/*physiology ; Staphylococcus aureus/growth & development/isolation & purification/*virology ; }, abstract = {Staphylococcus aureus may be a highly virulent human pathogen, especially when it is able to form a biofilm, and it is resistant to antibiotic. Infections caused by these bacteria significantly affect morbidity and mortality, primarily in hospitalized patients. Treatment becomes more expensive, more toxic, and prolonged. This is the reason why research on alternative therapies should be one of the main priorities of medicine and biotechnology. A promising alternative treatment approach is bacteriophage therapy. The effect of the anti-staphylococcal bacteriophage preparation Stafal® on biofilm reduction was assessed on nine S. aureus strains using both sonication with subsequent quantification of surviving cells on the catheter surface and evaluation of biofilm reduction in microtiter plates. It was demonstrated that the bacteriophages destroy planktonic cells very effectively. However, to destroy cells embedded in the biofilm effectively requires a concentration at least ten times higher than that provided by the commercial preparation. The catheter disc method (CDM) allowed easier comparison of the effect on planktonic cells and cells in a biofilm than the microtiter plate (MTP) method.}, } @article {pmid29922414, year = {2018}, author = {Turkey, AM and Barzani, KK and Suleiman, AAJ and Abed, JJ}, title = {Molecular assessment of accessory gene regulator (agr) quorum sensing system in biofilm forming Staphylococcus aureus and study of the effect of silver nanoparticles on agr system.}, journal = {Iranian journal of microbiology}, volume = {10}, number = {1}, pages = {14-21}, pmid = {29922414}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus aureus is an opportunistic human pathogen that causes a variety of diseases. Staphylococcal biofilms are a source of chronic and continual infections. This study was conducted to estimate the distribution of agr among different isolates of S. aureus and their relationship with biofilm. Also, it was aimed to check the association of operon agr with virulence factors (seb, eta, spa and tst v8) and study the effect of biosynthesis silver nanoparticles on the function of the agr system.

MATERIALS AND METHODS: Out of 580 clinical specimens, 100 S. aureus isolates were isolated and identified based on cultural, morphological, and different biochemical tests, in addition to molecular identification using PCR with specific primer 16SrRNA. For biofilm detection, the fungi synthesized silver nanoparticles were used to check its effect on agr system.

RESULTS: The biofilm producer among S. aureus was 61% and non-biofilm producer isolates were 39%. It was found that the total number of agr - bearing isolates was 31 (50.82%), with a significant difference in the distribution percentage of virulence factors genes in isolates of biofilm-forming S. aureus carried agr. The results also revealed a relationship between the agr-quorum sensing system and the prevalence of virulence genes in the isolated S. aureus. Silver nanoparticles (AgNPs) were synthesized by Agaricus compestris, and it was found that it activates the agr system in 31 (100%) of biofilm-forming and carrying operon agr after treatment with sub-MIC of AgNPs.

CONCLUSION: The findings of this study revealed that not all isolates of S. aureus have agr system. Also, it was found that AgNPs have a positive effect on bacterial virulence factors production and could be used for treatment or in cooperation with antibiotics to decrease resistance.}, } @article {pmid29922159, year = {2018}, author = {Liu, YY and Chen, XR and Gao, LF and Chen, M and Cui, WQ and Ding, WY and Chen, XY and God'spower, BO and Li, YH}, title = {Spectrum-Effect Relationships Between the Bioactive Ingredient of Syringa oblata Lindl. Leaves and Its Role in Inhibiting the Biofilm Formation of Streptococcus suis.}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {570}, pmid = {29922159}, issn = {1663-9812}, abstract = {Syringa oblata Lindl. (S. oblata) has been used in herbal medicines for treating bacterial diseases. It is also thought to inhibit Streptococcus suis (S. suis) biofilm formation. However, due to the inherent nature of the complexity in its chemical properties, it is difficult to understand the possible bioactive ingredients of S. oblata. The spectrum-effect relationships method was applied to screen the main active ingredients in S. oblata obtained from Heilongjiang Province based on gray relational analysis. The results revealed that Sub-MICs obtained from 10 batches of S. oblata could inhibit biofilm formation by S. suis. Gray relational analysis revealed variations in the contents of 15 main peaks and rutin was discovered to be the main active ingredient. Then, the function of rutin was further verified by inhibiting S. suis biofilm formation using crystal violet staining. Computational studies revealed that rutin may target the chloramphenicol acetyltransferase protein in the biofilm formation of S. suis. In conclusion, this study revealed that the spectrum-effect relationships and computational studies are useful tools to associate the active ingredient with the potential anti-biofilm effects of S. oblata. Here, our findings would provide foundation for the further understanding of the mechanism of S. oblata intervention in biofilm formation.}, } @article {pmid29921978, year = {2018}, author = {Duanis-Assaf, D and Duanis-Assaf, T and Zeng, G and Meyer, RL and Reches, M and Steinberg, D and Shemesh, M}, title = {Cell wall associated protein TasA provides an initial binding component to extracellular polysaccharides in dual-species biofilm.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {9350}, pmid = {29921978}, issn = {2045-2322}, mesh = {Bacterial Proteins/*metabolism ; *Biofilms ; Cell Wall/*metabolism ; Gene Expression Regulation, Bacterial ; Polysaccharides, Bacterial/*metabolism ; }, abstract = {Many bacteria in biofilm surround themselves by an extracellular matrix composed mainly of extracellular polysaccharide (EP), proteins such as amyloid-like fibers (ALF) and nucleic acids. While the importance of EP in attachment and acceleration of biofilm by a number of different bacterial species is well established, the contribution of ALF to attachment in multispecies biofilm remains unknown. The study presented here aimed to investigate the role of TasA, a precursor for ALF, in cell-cell interactions in dual-species biofilms of Bacillus subtilis and Streptococcus mutans. Expression of major B. subtilis matrix operons was significantly up-regulated in the presence of S. mutans during different stages of biofilm formation, suggesting that the two species interacted and modulated gene expression in each other. Wild-type B. subtilis expressing TasA adhered strongly to S. mutans biofilm, while a TasA-deficient mutant was less adhesive and consequently less abundant in the dual-species biofilm. Dextran, a biofilm polysaccharide, induced aggregation of B. subtilis and stimulated adhesion to S. mutans biofilms. This effect was only observed in the wild-type strain, suggesting that interactions between TasA and dextran-associated EP plays an important role in inter-species interactions during initial stages of multispecies biofilm development.}, } @article {pmid29921241, year = {2018}, author = {Lajhar, SA and Brownlie, J and Barlow, R}, title = {Correction to: Characterization of biofilm-forming capacity and resistance to sanitizers of a range of E.coli O26 pathotypes from clinical cases and cattle in Australia.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {61}, pmid = {29921241}, issn = {1471-2180}, abstract = {On page 4of the original publication [1], the correct sentence should read.}, } @article {pmid29920781, year = {2018}, author = {Herget, K and Frerichs, H and Pfitzner, F and Tahir, MN and Tremel, W}, title = {Functional Enzyme Mimics for Oxidative Halogenation Reactions that Combat Biofilm Formation.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {}, number = {}, pages = {e1707073}, doi = {10.1002/adma.201707073}, pmid = {29920781}, issn = {1521-4095}, abstract = {Transition-metal oxide nanoparticles and molecular coordination compounds are highlighted as functional mimics of halogenating enzymes. These enzymes are involved in halometabolite biosynthesis. Their activity is based upon the formation of hypohalous acids from halides and hydrogen peroxide or oxygen, which form bioactive secondary metabolites of microbial origin with strong antibacterial and antifungal activities in follow-up reactions. Therefore, enzyme mimics and halogenating enzymes may be valuable tools to combat biofilm formation. Here, halogenating enzyme models are briefly described, enzyme mimics are classified according to their catalytic functions, and current knowledge about the settlement chemistry and adhesion of fouling organisms is summarized. Enzyme mimics with the highest potential are showcased. They may find application in antifouling coatings, indoor and outdoor paints, polymer membranes for water desalination, or in aquacultures, but also on surfaces for food packaging, door handles, hand rails, push buttons, keyboards, and other elements made of plastic where biofilms are present. The use of natural compounds, formed in situ with nontoxic and abundant metal oxide enzyme mimics, represents a novel and efficient "green" strategy to emulate and utilize a natural defense system for preventing bacterial colonization and biofilm growth.}, } @article {pmid29920307, year = {2018}, author = {Rubini, D and Banu, SF and Nisha, P and Murugan, R and Thamotharan, S and Percino, MJ and Subramani, P and Nithyanand, P}, title = {Essential oils from unexplored aromatic plants quench biofilm formation and virulence of Methicillin resistant Staphylococcus aureus.}, journal = {Microbial pathogenesis}, volume = {122}, number = {}, pages = {162-173}, doi = {10.1016/j.micpath.2018.06.028}, pmid = {29920307}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biopolymers/metabolism ; Cinnamomum/*chemistry ; Hemolysin Proteins/biosynthesis ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*growth & development/metabolism ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Oils, Volatile/isolation & purification/*pharmacology ; Pogostemon/*chemistry ; Virulence/drug effects ; Virulence Factors/biosynthesis ; Xanthophylls/biosynthesis ; }, abstract = {In the current study we have evaluated the antibiofilm and antivirulent properties of unexplored essential oils (EOs) obtained from Pogostemon heyneanus and Cinnamomum tamala against Methicillin Resistant Staphylococcus aureus (MRSA) strains. The EOs from both the aromatic plants was screened for their ability to prevent biofilm formation and to disrupt preformed biofilms. The efficacy of both the EOs to disrupt the preformed biofilms of various MRSA strains was determined by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM).The EOs were further able to reduce the Extracellular polymeric substance (EPS) and slime synthesis the two factors of the biofilm assemblage. The EOs was also found to be effective in reducing virulence factors like staphyloxanthin and hemolysin. In silico docking studies were performed for the major components of essential oils and dehydroxysqualene synthase of MRSA which is responsible for the synthesis of staphyloxanthin. The results suggest that (E)-nerolidol showed better binding affinity towards the enzyme. Other compounds have similar binding strengths with the enzyme. Furthermore, the synergistic effect EOs along with the commercially available DNaseI and Marine Bacterial DNase (MBD) showed that the synergistic effect had enhanced biofilm disruption ability. The results show that EOs from P. heyneanus and C. tamala has potential antivirulent and biofilm inhibitory properties against clinical and drug resistant S. aureus strains. The present study highlights the importance of bioprospecting plant based natural products as an alternative for antibiotics owing to the emergence of multi-drug resistant strains.}, } @article {pmid29915708, year = {2018}, author = {Zhao, Y and Wang, Q and Li, J and Lin, X and Huang, X and Fang, B}, title = {Epidemiology of Haemophilus parasuis isolates from pigs in China using serotyping, antimicrobial susceptibility, biofilm formation and ERIC-PCR genotyping.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5040}, pmid = {29915708}, issn = {2167-8359}, abstract = {BACKGROUND: Haemophilus parasuis is a commensal organism of the upper respiratory tract of healthy pigs and causes high morbidity and mortality in piglets. The aim of this study was to investigate the epidemiology of H. parasuis in China from 2014 to 2017.

METHODS: We characterized 143 H. parasuis isolates by serotyping, antimicrobial susceptibility, biofilm formation and with enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) assays.

RESULTS: Serotyping revealed serovar 5 as the most prevalent (26.6%) followed by serovars 4 (22.4%), 7 (9.1 %), 13 (6.3%), 12 (5.6 %), and non-typeable (8.4%). In a panel of 23 antimicrobials, the minimum inhibitory concentration 50% (MIC50) were in the range of 0.25-16 μg/mL and MIC90 were 2->512 μg/mL. A total of 99 isolates of H. parasuis (69.2%) were able to form biofilms and 59.6% (59/99) performed weak biofilm-forming ability. ERIC-PCR revealed a very heterogeneous pattern with 87 clusters.

DISCUSSION: These H. parasuis isolates showed a high serovar and genotypic lineage diversity, different abilities to form biofilms and a high degree of genetic diversity. Biofilm formation was related to antimicrobial susceptibility but there were no statistically significant associations between the antimicrobial susceptibility and either the serovars or the ERIC-PCR clusters. This study showed a high prevalence of high-MIC H. parasuis strains and suggests the need for a continuous surveillance of clinical isolates of H. parasuis.}, } @article {pmid29915571, year = {2018}, author = {Li, WS and Chen, YC and Kuo, SF and Chen, FJ and Lee, CH}, title = {The Impact of Biofilm Formation on the Persistence of Candidemia.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1196}, pmid = {29915571}, issn = {1664-302X}, abstract = {This study aimed to determine the predictors of persistent candidemia and examine the impact of biofilm formation by Candida isolates in adult patients with candidemia. Of the adult patients with candidemia in Kaohsiung Chang Gung Memorial Hospital between January 2007 and December 2012, 68 case patients with persistent candidemia (repeated candidemia after a 3-day systemic antifungal therapy) and 68 control patients with non-persistent candidemia (Candida clearance from the bloodstream after a 3-day systemic antifungal therapy) were included based on propensity score matching and matching for the Candida species isolated. Biofilm formation by the Candida species was assessed in vitro using standard biomass assays. Presence of central venous catheters (CVCs) at diagnosis (adjusted odd ratio [AOR], 3.77; 95% confidence interval [CI], 1.09-13.00, p = 0.04), infection with higher biofilm forming strains of Candida species (AOR, 8.03; 95% CI, 2.50-25.81; p < 0.01), and receipt of suboptimal fluconazole doses as initial therapy (AOR, 5.54; 95% CI, 1.53-20.10; p < 0.01) were independently associated with persistent candidemia. Biofilm formation by Candida albicans, C. tropicalis, and C. glabrata strains was significantly higher in the case patients than in the controls. There were no significant differences in the overall mortality and duration of hospitalization between the two groups. Our data suggest that, other than presence of retained CVCs and use of suboptimal doses of fluconazole, biofilm formation was highly associated with development of persistent candidemia.}, } @article {pmid29915116, year = {2018}, author = {Ealand, C and Rimal, B and Chang, J and Mashigo, L and Chengalroyen, M and Mapela, L and Beukes, G and Machowski, E and Kim, SJ and Kana, B}, title = {Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {17}, pages = {}, pmid = {29915116}, issn = {1098-5336}, support = {R01 GM116130/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cell Wall/*chemistry/genetics ; Cytokines/*genetics ; Gene Deletion ; Microbial Sensitivity Tests ; Muramic Acids/chemistry ; Mycobacterium smegmatis/*genetics/*growth & development/metabolism ; Peptidoglycan/*genetics ; RNA, Messenger/genetics ; Rifampin/pharmacology ; Sodium Dodecyl Sulfate/pharmacology ; Vancomycin/pharmacology ; }, abstract = {Resuscitation-promoting factors (Rpfs) have previously been shown to act as growth-stimulatory molecules via their lysozyme-like activity on peptidoglycan in the bacterial cell wall. In this study, we investigated the ability of Mycobacterium smegmatis strains lacking rpf genes to form biofilms and tested their susceptibilities to cell wall-targeting agents. M. smegmatis contains four distinct rpf homologues, namely, MSMEG_5700 (rpfA), MSMEG_5439 (rpfB), MSMEG_4640 (rpfE2), and MSMEG_4643 (rpfE). During axenic growth of the wild-type strain, all four mRNA transcripts were expressed to various degrees, but the expression of MSMEG_4643 was significantly greater during exponential growth. Similarly, all rpf mRNA transcripts could be detected in biofilms grown for 7, 14, and 28 days, with MSMEG_4643 expressed at the highest abundance after 7 days. In-frame unmarked deletion mutants (single and combinatorial) were generated and displayed altered colony morphologies and the inability to form typical biofilms. Moreover, any strain lacking rpfA and rpfB simultaneously exhibited increased susceptibility to rifampin, vancomycin, and SDS. Exogenous Rpf supplementation in the form of culture filtrate failed to restore biofilm formation. Liquid chromatography-mass spectrometry (LC-MS) analysis of peptidoglycan (PG) suggested a reduction in 4-3 cross-linked PG in the ΔrpfABEE2 mutant strain. In addition, the level of PG-repeat units terminating in 1,6-anhydroMurNAc appeared to be significantly reduced in the quadruple rpf mutant. Collectively, our data have shown that Rpfs play an important role in biofilm formation, possibly through alterations in PG cross-linking and the production of signaling molecules.IMPORTANCE The cell wall of pathogenic mycobacteria is composed of peptidoglycan, arabinogalactan, mycolic acids, and an outer capsule. This inherent complexity renders it resistant to many antibiotics. Consequently, its biosynthesis and remodeling during growth directly impact viability. Resuscitation-promoting factors (Rpfs), enzymes with lytic transglycosylase activity, have been associated with the revival of dormant cells and subsequent resumption of vegetative growth. Mycobacterium smegmatis, a soil saprophyte and close relative of the human pathogen Mycobacterium tuberculosis, encodes four distinct Rpfs. Herein, we assessed the relationship between Rpfs and biofilm formation, which is used as a model to study drug tolerance and bacterial signaling in mycobacteria. We demonstrated that progressive deletion of rpf genes hampered the development of biofilms and reduced drug tolerance. These effects were accompanied by a reduction in muropeptide production and altered peptidoglycan cross-linking. Collectively, these observations point to an important role for Rpfs in mycobacterial communication and drug tolerance.}, } @article {pmid29915115, year = {2018}, author = {Shen, M and Yang, Y and Shen, W and Cen, L and McLean, JS and Shi, W and Le, S and He, X}, title = {A Linear Plasmid-Like Prophage of Actinomyces odontolyticus Promotes Biofilm Assembly.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {17}, pages = {}, pmid = {29915115}, issn = {1098-5336}, support = {R01 DE020102/DE/NIDCR NIH HHS/United States ; R01 DE023810/DE/NIDCR NIH HHS/United States ; R01 DE026186/DE/NIDCR NIH HHS/United States ; }, mesh = {Actinomyces/*growth & development/isolation & purification/*virology ; Biofilms/*growth & development ; Genome, Bacterial/genetics ; Genome, Viral/genetics ; Humans ; Lysogeny/genetics ; Microscopy, Electron, Transmission ; Mouth/microbiology ; Phylogeny ; Plasmids/genetics ; Prophages/*classification/*genetics/isolation & purification ; Siphoviridae/classification/genetics/isolation & purification ; }, abstract = {The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not well understood. Recently, we isolated Actinomyces odontolyticus subsp. actinosynbacter strain XH001 from the human oral cavity, and genomic analysis revealed the presence of an intact prophage named xhp1. Here, we demonstrated that xhp1 is a linear plasmid-like prophage, which is a newly identified phage of A. odontolyticus The prophage xhp1 genome is a 35-kb linear double-stranded DNA with 10-bp single-stranded, 3' cohesive ends. xhp1 exists extrachromosomally, with an estimated copy number of 5. Annotation of xhp1 revealed 54 open reading frames, while phylogenetic analysis suggests that it has limited similarity with other phages. xhp1 phage particles can be induced by mitomycin C and belong to the Siphoviridae family, according to transmission electron microscopic examination. The released xhp1 particles can reinfect the xhp1-cured XH001 strain and result in tiny blurry plaques. Moreover, xhp1 promotes XH001 biofilm formation through spontaneous induction and the release of host extracellular DNA (eDNA). In conclusion, we identified a linear plasmid-like prophage of A. odontolyticus, which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity.IMPORTANCE The biology of phages as members of the human oral microbiome is understudied. Here, we report the characterization of xhp1, a novel linear plasmid-like prophage identified from a human oral isolate, Actinomyces odontolyticus subsp. actinosynbacter strain XH001. xhp1 can be induced and reinfect xhp1-cured XH001. The spontaneous induction of xhp1 leads to the lysis of a subpopulation of bacterial hosts and the release of eDNA that promotes biofilm assembly, thus potentially contributing to the persistence of A. odontolyticus within the oral cavity.}, } @article {pmid29914658, year = {2018}, author = {Nesse, LL and Simm, R}, title = {Biofilm: A Hotspot for Emerging Bacterial Genotypes.}, journal = {Advances in applied microbiology}, volume = {103}, number = {}, pages = {223-246}, doi = {10.1016/bs.aambs.2018.01.003}, pmid = {29914658}, issn = {0065-2164}, mesh = {Bacteria/*genetics/*growth & development ; Biofilms/*growth & development ; Drug Resistance, Bacterial ; Evolution, Molecular ; *Gene Transfer, Horizontal ; *Genetic Variation ; *Genotype ; *Recombination, Genetic ; }, abstract = {Bacteria have the ability to adapt to changing environments through rapid evolution mediated by modification of existing genetic information, as well as by horizontal gene transfer (HGT). This makes bacteria a highly successful life form when it comes to survival. Unfortunately, this genetic plasticity may result in emergence and dissemination of antimicrobial resistance and virulence genes, and even the creation of multiresistant "superbugs" which may pose serious threats to public health. As bacteria commonly reside in biofilms, there has been an increased interest in studying these phenomena within biofilms in recent years. This review summarizes the present knowledge within this important area of research. Studies on bacterial evolution in biofilms have shown that mature biofilms develop into diverse communities over time. There is growing evidence that the biofilm lifestyle may be more mutagenic than planktonic growth. Furthermore, all three main mechanisms for HGT have been observed in biofilms. This has been shown to occur both within and between bacterial species, and higher transfer rates in biofilms than in planktonic cultures were detected. Of special concern are the observations that mutants with increased antibiotic resistance occur at higher frequency in biofilms than in planktonic cultures even in the absence of antibiotic exposure. Likewise, efficient dissemination of antimicrobial resistance genes, as well as virulence genes, has been observed within the biofilm environment. This new knowledge emphasizes the importance of biofilm awareness and control.}, } @article {pmid29913149, year = {2018}, author = {Dong, X and Liu, Y and Zhang, G and Wang, D and Zhou, X and Shao, J and Shen, Q and Zhang, R}, title = {Synthesis and detoxification of nitric oxide in the plant beneficial rhizobacterium Bacillus amyloliquefaciens SQR9 and its effect on biofilm formation.}, journal = {Biochemical and biophysical research communications}, volume = {503}, number = {2}, pages = {784-790}, doi = {10.1016/j.bbrc.2018.06.076}, pmid = {29913149}, issn = {1090-2104}, mesh = {Bacillus amyloliquefaciens/genetics/*growth & development/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Genes, Bacterial ; Nitric Oxide/*metabolism ; Plant Root Nodulation ; Plants/*microbiology ; *Rhizosphere ; }, abstract = {Nitric oxide (NO) is an important gas signal that regulates many biological processes, and due to the high nitrogen recycling activity in the rhizosphere, NO is an important signaling molecule in this region. Thus, an understanding of the effect of NO on the rhizomicrobiome, especially on plant beneficial rhizobacteria, is important for the use of these bacteria in agriculture. In this study, the effect of exogenous NO on the beneficial rhizobacterium Bacillus amyloliquefaciens SQR9 was investigated. The results showed that low concentrations of NO increased the ability of the strain SQR9 to form biofilms, while high concentrations of NO inhibited the growth of this bacterium. The SQR9 gene yflM encodes nitric oxide synthase (NOS), which is used to synthesize NO, while the gene ykvO encodes a sepiapterin reductase that is used to synthesize tetrahydrobiopterin, the coenzyme of NOS. Isothermal titration calorimetry and high-performance liquid chromatography analyses demonstrated an interaction between YkvO and NADPH. SQR9 has two hmp genes, although only one was observed to be responsible for NO detoxification through oxidization. This study revealed the effect of NO on plant beneficial rhizobacterium and assessed the ability of this strain to adapt to exogenous NO, which will help to improve the application of this strain in agricultural production.}, } @article {pmid29912894, year = {2018}, author = {Lagree, K and Mon, HH and Mitchell, AP and Ducker, WA}, title = {Impact of surface topography on biofilm formation by Candida albicans.}, journal = {PloS one}, volume = {13}, number = {6}, pages = {e0197925}, pmid = {29912894}, issn = {1932-6203}, mesh = {Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/*physiology ; Dimethylpolysiloxanes/chemistry/pharmacology ; Nylons/chemistry/pharmacology ; Silicon Dioxide/chemistry ; Surface Properties ; }, abstract = {Candida albicans is a fungal pathogen that causes serious biofilm-based infections. Here we have asked whether surface topography may affect C. albicans biofilm formation. We tested biofilm growth of the prototypical wild-type strain SC5314 on a series of polydimethylsiloxane (PDMS) solids. The surfaces were prepared with monolayer coatings of monodisperse spherical silica particles that were fused together into a film using silica menisci. The surface topography was varied by varying the diameter of the silica particles that were used to form the film. Biofilm formation was observed to be a strong function of particle size. In the particle size range 4.0-8.0 μm, there was much more biofilm than in the size range 0.5-2.0 μm. The behavior of a clinical isolate from a clade separate from SC5314, strain p76067, showed results similar to that of SC5314. Our results suggest that topographic coatings may be a promising approach to reduce C. albicans biofilm infections.}, } @article {pmid29911330, year = {2019}, author = {Gannesen, AV and Borrel, V and Lefeuvre, L and Netrusov, AI and Plakunov, VK and Feuilloley, MGJ}, title = {Effect of two cosmetic compounds on the growth, biofilm formation activity, and surface properties of acneic strains of Cutibacterium acnes and Staphylococcus aureus.}, journal = {MicrobiologyOpen}, volume = {8}, number = {3}, pages = {e00659}, pmid = {29911330}, issn = {2045-8827}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/*growth & development ; Cosmetics/*metabolism ; Metabolism/drug effects ; Propionibacterium acnes/*drug effects/*growth & development ; Staphylococcus aureus/*drug effects/*growth & development ; }, abstract = {Increasing popularity of preservative-free cosmetics necessitates in-depth research, specifically as bacteria can react to local factors by important metabolic changes. In this respect, investigating the effect of cosmetic preparations on pathogenic strains of commensal species such as acneic forms of Cutibacterium acnes (former Propionibacterium acnes) and bacteria behaving both as commensals and opportunistic pathogens such as Staphylococcus aureus is of major interest. In this study, we studied the effect of commonly used cosmetics, Uriage[™] thermal water (UTW) and a rhamnose-rich polysaccharide (PS291[®]) on RT4 and RT5 acneic strains of C. acnes and a cutaneous strain of S. aureus. UTW affected the growth kinetic of acneic C. acnes essentially by increasing its generation time and reducing its biomass, whereas only the S. aureus final biomass was decreased. PS291 had more marginal effects. Both compounds showed a marked antibiofilm activity on C. acnes and S. aureus. For S. aureus that appeared essentially due to inhibition of initial adhesion. Cosmetics did not modify the metabolic activity of bacteria. Both C. acnes and S. aureus showed marked hydrophobic surface properties. UTW and PS291 had limited effect on C. acnes but increased the hydrophobic character of S. aureus. This work underlines the effect of cosmetics on cutaneous bacteria and the potential limitations of preservative-free products.}, } @article {pmid29910567, year = {2018}, author = {Oliva, A and Mascellino, MT and Nguyen, BL and De Angelis, M and Cipolla, A and Di Berardino, A and Ciccaglioni, A and Mastroianni, CM and Vullo, V}, title = {Detection of Biofilm-associated Implant Pathogens in Cardiac Device Infections: High Sensitivity of Sonication Fluid Culture Even in the Presence of Antimicrobials.}, journal = {Journal of global infectious diseases}, volume = {10}, number = {2}, pages = {74-79}, pmid = {29910567}, issn = {0974-777X}, abstract = {INTRODUCTION: Sonication showed more sensitivity than traditional culture in the diagnosis of device infections. Aims of the study were to assess the role of sonication in the microbiological diagnosis and management of cardiac device infections (CDIs), to evaluate the sensitivity of sonication in patients on antimicrobial therapy at the time of device removal, and to analyze biofilm formation of the isolated strains.

MATERIALS AND METHODS: A total of 90 devices (31 generators and 59 electrodes) collected from 31 patients with infection underwent sonication before culture. Devices were sonicated for 5 min and centrifuged at 3200 rpm for 15 min. Intraoperative traditional cultures were performed in 26 patients. Microorganisms were identified using conventional methods. Staphylococcal strains were tested for slime production.

RESULTS: Microbiological diagnosis was achieved in 28 patients (90%). Sonicate fluid was positive in 68/90 (76%) of devices (27/31 [87%] generators and 41/59 [69%] electrodes), whereas intraoperative pocket swabs grew bacteria in 10/26 patients (38%, P = 0.0007). Among leads, 37/59 (62.7%) yielded bacteria even in the absence of vegetation. Coagulase-negative Staphylococci accounted for 83.8% (57/68) of the total; Staphylococcus aureus and Gram-negative bacilli were found in 4.4% (3/68) and 5.8% (4/68), respectively. Biofilm production was present in 15/22 (69%) staphylococcal strains. Overall, patients on therapy (n = 23) had a microbiological diagnosis in 20/23 (86.9%) and 7/22 (30.4%) through sonication and intraoperative cultures, respectively (P = 0.0002).

DISCUSSION: Our data showed the high sensitivity of sonication in the diagnosis of CDIs, even in patients under antimicrobial therapy.

CONCLUSION: Sonication represents an essential tool for both diagnosis and management of CDIs.}, } @article {pmid29909524, year = {2019}, author = {Bakal, T and Janata, J and Sabova, L and Grabic, R and Zlabek, V and Najmanova, L}, title = {Suitability and setup of next-generation sequencing-based method for taxonomic characterization of aquatic microbial biofilm.}, journal = {Folia microbiologica}, volume = {64}, number = {1}, pages = {9-17}, pmid = {29909524}, issn = {1874-9356}, support = {CZ.1.05/2.1.00/01.0024//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; CZ.1.05/2.1.00/01.0024//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; LO1205 under the NPU I program//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; LO1205 under the NPU I program//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; LQ1604 under the National Sustainability Program II//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; LQ1604 under the National Sustainability Program II//Ministerstvo Školství, Mládeže a Tělovýchovy/ ; CZ.1.05/1.1.00/02.0109//European Regional Development Fund/ ; CZ.1.05/1.1.00/02.0109//European Regional Development Fund/ ; 15-04258S//Grantová Agentura České Republiky/ ; 15-04258S//Grantová Agentura České Republiky/ ; 15-04258S//Grantová Agentura České Republiky/ ; 15-04258S//Grantová Agentura České Republiky/ ; 15-04258S//Grantová Agentura České Republiky/ ; 15-04258S//Grantová Agentura České Republiky/ ; }, mesh = {Bacteria/classification/genetics ; *Biofilms/growth & development ; Environmental Monitoring/*methods ; *High-Throughput Nucleotide Sequencing ; Microbiota/*genetics ; RNA, Ribosomal, 16S/genetics ; Reproducibility of Results ; *Sequence Analysis, DNA ; Specimen Handling ; *Water Microbiology ; }, abstract = {A robust and widely applicable method for sampling of aquatic microbial biofilm and further sample processing is presented. The method is based on next-generation sequencing of V4-V5 variable regions of 16S rRNA gene and further statistical analysis of sequencing data, which could be useful not only to investigate taxonomic composition of biofilm bacterial consortia but also to assess aquatic ecosystem health. Five artificial materials commonly used for biofilm growth (glass, stainless steel, aluminum, polypropylene, polyethylene) were tested to determine the one giving most robust and reproducible results. The effect of used sampler material on total microbial composition was not statistically significant; however, the non-plastic materials (glass, metal) gave more stable outputs without irregularities among sample parallels. The bias of the method is assessed with respect to the employment of a non-quantitative step (PCR amplification) to obtain quantitative results (relative abundance of identified taxa). This aspect is often overlooked in ecological and medical studies. We document that sequencing of a mixture of three merged primary PCR reactions for each sample and further evaluation of median values from three technical replicates for each sample enables to overcome this bias and gives robust and repeatable results well distinguishing among sampling localities and seasons.}, } @article {pmid29909325, year = {2018}, author = {Qiu, Y and Zhang, J and Li, B and Wen, X and Liang, P and Huang, X}, title = {A novel microfluidic system enables visualization and analysis of antibiotic resistance gene transfer to activated sludge bacteria in biofilm.}, journal = {The Science of the total environment}, volume = {642}, number = {}, pages = {582-590}, doi = {10.1016/j.scitotenv.2018.06.012}, pmid = {29909325}, issn = {1879-1026}, mesh = {*Biofilms ; Drug Resistance, Microbial/*genetics ; Gene Transfer, Horizontal ; *Microfluidics ; Plasmids ; Sewage/*microbiology ; }, abstract = {Antibiotic resistance genes (ARGs) in environment have become a growing public concern, due to their potential to be obtained by pathogens and their duplication along cell division. Horizontal gene transfer (HGT) was reported to be responsible for ARGs dissemination in microbes, but the HGT feature in environmental biofilm was still unclear due to insufficient assay tools. To address this challenge, we applied a novel microfluidic system to cultivate thin biofilm by continuous supply of nutrients and close contact between cells. Resembling the living state of biofilm in open environment, this chip visualized the transfer of ARG-encoded plasmids RP4 and pKJK5 to the receptors, e.g., activated sludge bacteria. The average plasmid transfer frequency per receptor (T/R) from RP4-hosted Pseudomonas putida KT2440 to activated sludge bacteria was quantified to be 2.5 × 10[-3] via flow cytometry, and T/R for pKJK5-hosted Escherichia coli MG1655 was 8.9 × 10[-3], while the corresponding average frequencies per donor (T/D) were diverse for the two host strains as 4.3 × 10[-3] and 1.4 × 10[-1] respectively. The difference between T/R and T/D was explained by the plasmid transfer kinetics, implying specific purposes of the two calculations. Finally, we collected the transconjugants by fluorescent activated cell sorting and further sequenced their 16S rDNA. Bacteria from phyla Proteobacteria and Firmicutes were found more susceptible to be transconjugants than those from Bacteroidetes. Our work demonstrated that microfluidic system was advantageous in biofilm HGT study, which can provide more insights into environmental ARG control.}, } @article {pmid29908271, year = {2018}, author = {Chen, KJ and Lee, CK}, title = {Twofold enhanced dispersin B activity by N-terminal fusion to silver-binding peptide for biofilm eradication.}, journal = {International journal of biological macromolecules}, volume = {118}, number = {Pt A}, pages = {419-426}, doi = {10.1016/j.ijbiomac.2018.06.066}, pmid = {29908271}, issn = {1879-0003}, mesh = {Acetylglucosamine/analogs & derivatives/chemistry ; Bacterial Proteins/chemistry/genetics/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/chemistry/genetics ; Glycoside Hydrolases/chemistry/genetics/*pharmacology ; Humans ; Hydrolysis ; Metal Nanoparticles/chemistry ; Peptides/chemistry/genetics/*pharmacology ; Recombinant Fusion Proteins/chemistry/genetics/*pharmacology ; Silver/chemistry ; Staphylococcus epidermidis/drug effects/growth & development/pathogenicity ; beta-Glucans/chemistry ; }, abstract = {Dispersin B (DspB) has shown a great potential for the hydrolysis of polymeric β-1,6-N-acetyl-d-glucosamine (PNAG) to disperse the biofilms formed by various bacteria but with no killing activity. Here we have investigated whether a silver-binding peptide (AgBP) fused to DspB can induce the in situ formation of silver nanoparticles (AgNP) and conjugated to the structure of DspB so that the bacteria cells released from the dispersed biofilm will be killed by the conjugated AgNP. However, the desired conjugate could be obtained because of the silver ions itself was found to precipitate DspB. But, the fusion of AgBP2 to DspB (AgBP2-DspB) could generate at least 2 fold higher activity against soluble substrate 4-nitrophenyl N-acetyl-β-D-glucosaminide (NP-GlcNAc). By applying to a preformed Staphylococcus epidermidis biofilm, AgBP2-DspB could clear 69% of the biofilm while only 37% could be cleared by DspB as observed by fluorescent microscope. As measured by crystal violet staining, biofilm could be eradicated to the same extent by loading AgBP2-DspB activity level approximately 20 fold lower than that of DspB. The biofilm formation could be prevented on a AgBP2-DspB immobilized surface as observed by confocal laser microscope.}, } @article {pmid29908228, year = {2018}, author = {Mashima, I and Miyakawa, H and Scannapieco, FA and Nakazawa, F}, title = {Identification of an early stage biofilm inhibitor from Veillonella tobetsuensis.}, journal = {Anaerobe}, volume = {52}, number = {}, pages = {86-91}, doi = {10.1016/j.anaerobe.2018.06.005}, pmid = {29908228}, issn = {1095-8274}, mesh = {Biofilms/*drug effects ; Dental Caries/microbiology ; Dipeptides/*chemistry/metabolism/*pharmacology ; Humans ; Veillonella/*chemistry/drug effects/physiology ; }, abstract = {Oral biofilm, the cause of dental caries and periodontal diseases, consists of multiple bacterial species. Streptococcus spp. and Veillonella spp. have been reported as to be initial and early colonizers of oral biofilms. Our previous studies showed that Veillonella tobetsuensis may play an important role on the development of S. gordonii biofilms without coaggregation involving extracellular biomolecules. In this study, the effect of a cyclic dipeptide autoinducer from culture supernatants from V. tobetsuensis at late-exponential growth phase on S. gordonii biofilm was examined. The cyclic dipeptide, identified as cyclo (-L-Leu-L-Pro) by gas chromatography/mass spectrometry, inhibited the development of S. gordonii biofilm. Furthermore, cyclo (-L-Leu-L-Pro) appeared not to cause bactericidal effects on planktonic cells of S. gordonii. This is the first report that oral Veillonella produces cyclo (-L-Leu-L-Pro) in their culture supernatants. Moreover, the results of this study suggest that cyclo (-L-Leu-L-Pro) may have an application to inhibit early stage development of oral biofilms.}, } @article {pmid29906542, year = {2018}, author = {Wang, Q and Chen, H and Yang, Y and Wang, B}, title = {Expression of Neu5Acα2,3Gal and Neu5Acα2,6Gal on the nasal mucosa of patients with chronic rhinosinusitis and its possible effect on bacterial biofilm formation.}, journal = {Microbial pathogenesis}, volume = {123}, number = {}, pages = {24-27}, doi = {10.1016/j.micpath.2018.06.018}, pmid = {29906542}, issn = {1096-1208}, mesh = {Adolescent ; Adult ; Aged ; Bacteria/*growth & development ; Biofilms/*growth & development ; Disaccharides/*biosynthesis ; Female ; Humans ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; N-Acetylneuraminic Acid/chemistry/metabolism ; Nasal Mucosa/*metabolism/microbiology ; Sinusitis/*microbiology ; Young Adult ; }, abstract = {OBJECTIVE: Adherence of pathogen to nasal mucosa and colonization is the first step of bacterial biofilm(BBF) formation in patients with chronic rhinosinusitis (CRS).Terminal sialic acids presenting on cell surface are potential targets for bacterial binding, thus may partly contribute to the pathogenesis of CRS. However, little has been published in this respect, the purpose of our study aimed to investigate the expression of sialic acids on the nasal mucosa in CRS patients and its possible effect on BBF formation.

METHODS: Sinus mucosa were harvested from CRS patients undergoing endoscopic surgery. The positive of BBF formation were detected by scanning electronic microscopy (SEM) and the expression of Neu5Acα2,3Gal(α2,3-linked sialic acid) and Neu5Acα2,6Gal(α2,6-linked sialic acid) on nasal mucosa were determined by fluorescent-immunohistochemical staining (F-IHC) with MAL-II and SNA respectively. A semi-quantitative scoring system was used to assess their different expression between CRS group and the control, as well as BBF positive and negative group.

RESULTS: Expression of Neu5Acα2,3Gal and Neu5Acα2,6Gal were both detected in the epithelium and submucosal glands of all 40 CRS patients and 23 controls, they were significantly up-regulated in CRS group(p < 0.05). Among 24 CRS patients, typical BBF formation were identified in 13 cases while the other 11 were regarded as negative, Between the subgroup of BBF(+) and BBF(-), both of Neu5Acα2,3Gal and Neu5Acα2,6Gal had a trend of increasing in BBF(+) group, however, the increased expression of Neu5Acα2,3Gal was statistical significance (4.77 ± 0.90 versus 3.45 ± 1.40; p = 0.0282), whereas the difference of Neu5Acα2,6Gal was insignificant(4.15 ± 1.27 versus 3.55 ± 1.59; p = 0.4281).

CONCLUSION: Expression of MAL-II binding (most probable Neu5Acα2,3Gal) and SNA binding (Neu5Acα2,6Gal) were up-regulated in inflamed nasal mucosa, and the increased expression of them may contribute to bacterial biofilm formation which deserved a further investigation.}, } @article {pmid29904559, year = {2018}, author = {McOwat, K and Stanley-Wall, NR}, title = {Biofilm Building: A Simple Board Game to Reinforce Knowledge of Biofilm Formation.}, journal = {Journal of microbiology & biology education}, volume = {19}, number = {1}, pages = {}, pmid = {29904559}, issn = {1935-7877}, } @article {pmid29902652, year = {2018}, author = {Rossi, R and Yang, W and Zikmund, E and Pant, D and Logan, BE}, title = {In situ biofilm removal from air cathodes in microbial fuel cells treating domestic wastewater.}, journal = {Bioresource technology}, volume = {265}, number = {}, pages = {200-206}, doi = {10.1016/j.biortech.2018.06.008}, pmid = {29902652}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Biofouling ; Electricity ; Electrodes ; *Wastewater ; }, abstract = {One challenge in using microbial fuel cells (MFCs) for wastewater treatment is the reduction in performance over time due to cathode fouling. An in-situ technique was developed to clean air cathodes using magnets on either side of the electrode, with the air-side magnet moved to clean the water-side magnet by scraping off the biofilm. The power output of the magnet-cleaned cathodes after one month of operation was 132 ± 7 mW m[-2], which was 42% higher than the controls with no magnet (93 ± 4 mW m[-2]) (no separator, NS), and 110% higher (116 ± 4 mW m[-2]) than controls with separators (Sp, 55 ± 7 mW m[-2]). Cleaning cathodes using magnets reduced the biofilm by 75% (NS) and 28% (Sp). The in-situ cleaning technique thus improved the performance of the MFC over time by reducing biofouling due to biofilm formation on the air cathodes.}, } @article {pmid29902594, year = {2018}, author = {Rzhepishevska, O and Limanska, N and Galkin, M and Lacoma, A and Lundquist, M and Sokol, D and Hakobyan, S and Sjöstedt, A and Prat, C and Ramstedt, M}, title = {Characterization of clinically relevant model bacterial strains of Pseudomonas aeruginosa for anti-biofilm testing of materials.}, journal = {Acta biomaterialia}, volume = {76}, number = {}, pages = {99-107}, doi = {10.1016/j.actbio.2018.06.019}, pmid = {29902594}, issn = {1878-7568}, mesh = {Bacterial Adhesion/*drug effects ; *Biofilms/drug effects/growth & development ; *Coated Materials, Biocompatible/chemistry/pharmacology ; Humans ; Pseudomonas aeruginosa/isolation & purification/*physiology ; }, abstract = {UNLABELLED: There is a great interest in developing novel anti-biofilm materials in order to decrease medical device-associated bacterial infections causing morbidity and high healthcare costs. However, the testing of novel materials is often done using bacterial lab strains that may not exhibit the same phenotype as clinically relevant strains infecting medical devices. Furthermore, no consensus of strain selection exists in the field, making results very difficult to compare between studies. In this work, 19 clinical isolates of Pseudomonas aeruginosa originating from intubated patients in an intensive care unit have been characterized and compared to the lab reference strain PAO1 and a rmlC lipopolysaccharide mutant of PAO1. The adhesion and biofilm formation was monitored, as well as cell properties such as hydrophobicity, zeta potential and motility. Two groups of isolates were observed: one with high adhesion to polymer surfaces and one with low adhesion (the latter including PAO1). Furthermore, detailed biofilm assays in a flow system were performed using five characteristic isolates from the two groups. Confocal microscopy showed that the adhesion and biofilm formation of four of these five strains could be reduced dramatically on zwitterionic surface coatings. However, one isolate with pronounced swarming colonized and formed biofilm also on the antifouling surface. We demonstrate that the biofilm properties of clinical isolates can differ greatly from that of a standard lab strain and propose two clinical model strains for testing of materials designed for prevention of biofilm formation in the respiratory tract. The methodology used could beneficially be applied for screening of other collections of pathogens to identify suitable model strains for in vitro biofilm testing.

STATEMENT OF SIGNIFICANCE: Medical-device associated infections present a great challenge in health care. Therefore, much research is undertaken to prevent bacterial colonization of new types of biomaterials. The work described here characterizes, tests and presents a number of clinically relevant bacterial model strains for assessing biofilm formation by Pseudomonas aeruginosa. Such model strains are of importance as they may provide better predictability of lab testing protocols with respect to how well materials would perform in an infection situation in a patient. Furthermore, this study uses the strains to test the performance of polymer surfaces designed to repel bacterial adhesion and it is shown that the biofilm formation for four out of the five tested bacterial strains was reduced.}, } @article {pmid29902257, year = {2018}, author = {Schkolnik, G and Schmidt, M and Mazza, MG and Harnisch, F and Musat, N}, title = {Correction: In Situ Analysis of a Silver Nanoparticle-Precipitating Shewanella Biofilm by Surface Enhanced Confocal Raman Microscopy.}, journal = {PloS one}, volume = {13}, number = {6}, pages = {e0199344}, pmid = {29902257}, issn = {1932-6203}, abstract = {[This corrects the article DOI: 10.1371/journal.pone.0145871.].}, } @article {pmid29901811, year = {2018}, author = {Tavernier, S and Sass, A and De Bruyne, M and Baeke, F and De Rycke, R and Crabbé, A and Vandecandelaere, I and Van Nieuwerburgh, F and Coenye, T}, title = {Decreased susceptibility of Streptococcus anginosus to vancomycin in a multispecies biofilm is due to increased thickness of the cell wall.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {9}, pages = {2323-2330}, doi = {10.1093/jac/dky216}, pmid = {29901811}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Wall/*drug effects/metabolism/ultrastructure ; Gene Expression Profiling ; Microbial Consortia/drug effects ; Microscopy, Electron, Transmission ; Pseudomonas aeruginosa/growth & development ; Staphylococcus aureus/growth & development ; Streptococcus anginosus/*drug effects/genetics/growth & development/ultrastructure ; Vancomycin/*pharmacology ; *Vancomycin Resistance ; }, abstract = {BACKGROUND: Streptococcus anginosus, Pseudomonas aeruginosa and Staphylococcus aureus are often co-isolated from the sputum of cystic fibrosis patients. It was recently shown that S. anginosus is protected from the activity of vancomycin when it grows in a multispecies biofilm with P. aeruginosa and S. aureus.

OBJECTIVES: Elucidating the underlying cause of the reduced susceptibility of S. anginosus to vancomycin when growing in a multispecies biofilm with P. aeruginosa and S. aureus.

METHODS: The transcriptome of S. anginosus growing in a multispecies biofilm was compared with that of a S. anginosus monospecies biofilm. Subsequently, transmission electron microscopy was performed to investigate changes in cell wall morphology in S. anginosus and S. aureus in response to growth in multispecies biofilm and to vancomycin treatment.

RESULTS: S. anginosus responds to growth in a multispecies biofilm with induction of genes involved in cell envelope biogenesis. Cell walls of S. anginosus cultured in a multispecies biofilm were thicker than in a monospecies biofilm, without antibiotic challenge. S. aureus, when cultured in a multispecies biofilm, does not respond to vancomycin treatment with cell wall thickening.

CONCLUSIONS: Growth in multispecies biofilms can have an impact on the expression of genes related to cell wall synthesis and on the cell wall thickness of S. anginosus.}, } @article {pmid29901711, year = {2018}, author = {Wang, S and Yang, D and Wu, X and Wang, Y and Wang, D and Tian, M and Li, T and Qi, J and Wang, X and Ding, C and Yu, S}, title = {Autotransporter MisL of Salmonella enterica serotype Typhimurium facilitates bacterial aggregation and biofilm formation.}, journal = {FEMS microbiology letters}, volume = {365}, number = {17}, pages = {}, doi = {10.1093/femsle/fny142}, pmid = {29901711}, issn = {1574-6968}, mesh = {Animals ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; HeLa Cells ; Humans ; Membrane Transport Proteins/genetics/*metabolism ; Mice ; Salmonella Infections/*microbiology ; Salmonella typhimurium/genetics/pathogenicity/*physiology ; Type V Secretion Systems/genetics/metabolism ; Virulence ; }, abstract = {Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important food-borne zoonotic pathogen that causes increased morbidity and mortality worldwide. The autotransporter (AT) proteins are a large and diverse family of extracellular proteins, many of which contribute to the pathogenicity of Gram-negative bacteria. The S. Typhimurium AT protein MisL mediates intestinal colonization in mice. Bioinformatics analyses indicated that MisL clusters with ATs are involved in bacterial biofilm formation, aggregation and adherence. In this study, we found that the misL overexpression increased S. Typhimurium biofilm formation. In addition, the misL deletion reduced bacterial adherence and invasion abilities on HeLa cells, but did not affect the bacterial virulence. Similarly, MisL expression in Escherichia coli strain promoted bacterial biofilm formation as well as adhesion and invasion capacities. However, the misL overexpression had no influence on the bacterial aggregation except for AAEC189Δflu, a strain lacking type I fimbriae. Moreover, we demonstrated that immunization with recombinant MisL protein stimulated the production of high IgG antibody titers, which conferred modest protection against S. Typhimurium infection. This study illustrates the novel biological functions and immunoprotective effects of MisL in S. Typhimurium.}, } @article {pmid29901293, year = {2018}, author = {Tsukanov, AY and Akhmetov, DS and Blesman, AI and Rogachev, EA}, title = {[The impact of ureteral stent surface on encrustation and biofilm formation].}, journal = {Urologiia (Moscow, Russia : 1999)}, volume = {}, number = {2}, pages = {40-45}, pmid = {29901293}, issn = {1728-2985}, mesh = {Biofilms/*growth & development ; *Coated Materials, Biocompatible ; Humans ; *Stents ; Surface Properties ; *Ureter ; }, abstract = {INTRODUCTION: Encrustation and biofilm formation is a clinical problem occurring with indwelling urinary drainage devices routinely used in urological practice.

AIM: To investigate the impact of ureteral stent surface on encrustation and biofilm formation.

MATERIALS AND METHODS: Polyurethane stents of two manufacturers were examined using the scanning electron microscopy and scanning probe microscopy before use and three weeks after their initial ureteral placement in patients with no evidence of a urinary tract infection and urolithiasis.

RESULTS: In one case, there were irregularities in the form of pyramids with a height of 0.15+/-0.02 m with a tendency to occur at regular intervals, forming ordered rows, with a density of 2.67 per 10 m2. The cross-sectional area of the irregularities in the probe displacement direction was 1.015 m, after use - 1.271 m (25.2% increase). In another case, pyramids with a height of 0.39+/-0.03 m (p<0.0001) were detected without the pattern of repetition in the form of a network, the density was 3.31+/-10 m2. The cross-sectional area of the irregularities was 1.158 and 2.29 m2, respectively (an increase of 97.8%). In the first case, after three weeks of stent placement, the pyramids increased twofold, were amenable to counting, the biofilms had the appearance of scattered "loose" formations. In the second case, there were polygonal conglomerates of salts dozens of times larger than the primary elements; biofilms had the appearance of well-formed massive layers.

CONCLUSION: The nature of the ureteral stent surface exerts a direct independent effect on the degree of encrustation and the formation of biofilms.}, } @article {pmid29901218, year = {2018}, author = {Kviatkovski, I and Mamane, H and Lakretz, A and Sherman, I and Beno-Moualem, D and Minz, D}, title = {Resistance of a multiple-isolate marine culture to ultraviolet C irradiation: inactivation vs biofilm formation.}, journal = {Letters in applied microbiology}, volume = {67}, number = {3}, pages = {278-284}, doi = {10.1111/lam.13032}, pmid = {29901218}, issn = {1472-765X}, mesh = {Bacteria/classification/isolation & purification/*radiation effects ; Bacterial Physiological Phenomena/radiation effects ; Biofilms/*radiation effects ; Filtration ; Seawater/chemistry/*microbiology ; Ultraviolet Rays ; }, abstract = {UNLABELLED: Ultraviolet (UV) irradiation is an emerging strategy for controlling the formation of undesired biofilms in water desalination facilities using reverse osmosis (RO). However, most studies examining these pretreatments are limited as they have been conducted on single-species cultures, while biofilms are composed of multiple-species communities. The goal of this study was to investigate the effect of UV-C irradiation on a model community composed of six environmental isolates from a marine biofilm formed in RO seawater desalination plant. There was a high variance in the susceptibility of the single-isolate cultures to UV-C, from no response (isolate Eryth23) to complete inactivation (isolate Vib3). The most active wavelength was around 260 nm, resulting in a loss of viability of single-isolate cultures and loss of vitality of the mixed-isolate cultures. With respect to biofilm formation, the activity of this wavelength was completely different compared to its activity on planktonic suspension. Irradiation with 260 nm did not inhibit the total biofilm formation by the six-isolate culture; moreover, isolates such as the resistant Eryth23 or the susceptible Pseudoalt17, even gained abundance in the mixed isolate biofilm. The only decrease in total biofilm was obtained from irradiation at 280 nm, which was less active against the planktonic culture. These results indicate that the complexity of the biofilm-forming microbial community may contribute to its resistance to UV-C irradiation.

This study examined the resistance of a multiple-isolate native marine culture to UV-C irradiation, in terms of viability, vitality and the ability to form biofilm. Results of this study showed that even though most of the cells were inactivated both in single-isolate and in multiple-isolate cultures, still the multiple-isolate cultures manages to form biofilms, surprisingly with higher biomass than without irradiation. The significance of the study is in its conclusion that studies on UV-C irradiation of biofilm-forming model micro-organisms are not always applicable to natural multiple-species communities.}, } @article {pmid29900920, year = {2018}, author = {de Almeida, J and Cechella, BC and Bernardi, AV and de Lima Pimenta, A and Felippe, WT}, title = {Effectiveness of nanoparticles solutions and conventional endodontic irrigants against Enterococcus faecalis biofilm.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {29}, number = {3}, pages = {347-351}, doi = {10.4103/ijdr.IJDR_634_15}, pmid = {29900920}, issn = {1998-3603}, mesh = {Bicuspid ; Biofilms/*drug effects ; Enterococcus faecalis/*drug effects ; Humans ; In Vitro Techniques ; *Metal Nanoparticles ; Microscopy, Electron, Scanning ; Root Canal Irrigants/*pharmacology ; Silver ; Zinc Oxide ; }, abstract = {CONTEXT: To overcome the challenge imposed by the presence of biofilm and reach significant bacterial reduction of the root canals, many irrigants have been indicated during endodontic treatment, among them nanoparticles solutions.

AIMS: This study aims to evaluate the effectiveness of experimental solutions containing silver and zinc oxide nanoparticles (ZnO Np) and conventional endodontic irrigants against Enterococcus faecalis biofilm, in root canals.

METHODS: Seventy-six extracted human teeth were biomechanically prepared and sterilized. The root canal surface was exposed to E. faecalis suspension to form a 7-day-old biofilm. Four teeth were analyzed by scanning electron microscopy (SEM) to confirm the presence of biofilm. The remaining teeth were randomly divided into 6 groups (n = 12) and treated with passive ultrasonic irrigation and different solutions: G1 - 0.85% saline (control); G2 - 2% chlorhexidine gluconate (CHX); G3 - 5% sodium hypochlorite (NaOCl); G4 - 1% NaOCl; G5 - 1% silver nanoparticles (Ag Np) solution; and G6 - 26% ZnO Np solution. The susceptibility of E. faecalis biofilms to disinfecting solutions (n = 10) was determined by quantification of colony-forming units. SEM analysis was also carried out to examine the biofilm structure after treatments (n = 2). Data were analyzed by Kruskal-Wallis and Dunn post hoc tests (P < 0.05).

RESULTS: All tested solutions showed superior effectiveness compared to 0.85% saline (P < 0.05). Overall, 2% CHX presented the most effective action against E. faecalis biofilm, followed by 5% NaOCl, 1% Ag Np, 26% ZnO Np, and 1% NaOCl.

CONCLUSIONS:: 1% Ag Np and 26% ZnO Np were effective against E. faecalis biofilm similarly to conventional endodontic irrigants.}, } @article {pmid29900886, year = {2018}, author = {Oriani, AS and Sierra, F and Baldini, MD}, title = {Effect of chlorine on Mycobacterium gordonae and Mycobacterium chubuense in planktonic and Biofilm State.}, journal = {International journal of mycobacteriology}, volume = {7}, number = {2}, pages = {122-127}, doi = {10.4103/ijmy.ijmy_30_18}, pmid = {29900886}, issn = {2212-554X}, mesh = {Biofilms/*drug effects ; Disinfectants/*pharmacology ; Disinfection ; Mycobacterium/*drug effects/growth & development/physiology ; Nontuberculous Mycobacteria/*drug effects/growth & development/physiology ; Plankton/drug effects/physiology ; Sodium Hypochlorite/*pharmacology ; }, abstract = {BACKGROUND: : There is evidence that drinking water could be a source of infections with pathogenic nontuberculous mycobacteria (NTM) potentially risky to human health. The aim was to investigate the resistance of two NTM isolated from drinking water, Mycobacterium gordonae and Mycobacterium chubuense, at different concentrations of chlorine (as sodium hypochlorite), used in drinking water sanitation.

METHODS: : The NTM were grown in suspension and in biofilms and were challenged with biocide for 10 and 60 min.

RESULTS: To obtain 7-log reduction from the initial population of M. chubuense, in the planktonic state, there were necessary 20 ppm of chorine and 60 min of exposure. The same effect was achieved in M. gordonae with 10 ppm for the same period. The maximum reduction of both NTM in biofilm was 3-log reduction and was achieved using 30 ppm for 60 min. The chlorine susceptibility of cells in biofilms was significantly lower than that of planktonic cells. The results highlight the resistance of both NTM to the concentrations used in routine water sanitation (0.2 ppm according to Argentine Food Code). Differences in chlorine resistance found between the two NTM in planktonic growth decrease when they are grown in biofilm.

CONCLUSION: This suggests that current water disinfection procedures do not always achieve effective control of NTM in the public supply system, with the consequent health risk to susceptible population, and the need to take into account biofilms, because of their deep consequences in the way to analyze the survival of prokaryotic cells in different environments.}, } @article {pmid29899738, year = {2018}, author = {Lai, LY and Lin, TL and Chen, YY and Hsieh, PF and Wang, JT}, title = {Role of the Mycobacterium marinum ESX-1 Secretion System in Sliding Motility and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1160}, pmid = {29899738}, issn = {1664-302X}, abstract = {Mycobacterium marinum is a close relative of Mycobacterium tuberculosis that can cause systemic tuberculosis-like infections in ectotherms and skin infections in humans. Sliding motility correlates with biofilm formation and virulence in most bacteria. In this study, we used a sliding motility assay to screen 2,304 transposon mutants of M. marinum NTUH-M6885 and identified five transposon mutants with decreased sliding motility. Transposons that interrupted the type VII secretion system (T7SS) ESX-1-related genes, espE (mmar_5439), espF (mmar_5440), and eccA1 (mmar_5443), were present in 3 mutants. We performed reverse-transcription polymerase chain reaction to verify genes from mmar_5438 to mmar_5450, which were found to belong to a single transcriptional unit. Deletion mutants of espE, espF, espG (mmar_5441), and espH (mmar_5442) displayed significant attenuation regarding sliding motility and biofilm formation. M. marinum NTUH-M6885 possesses a functional ESX-1 secretion system. However, deletion of espG or espH resulted in slightly decreased secretion of EsxB (which is also known as CFP-10). Thus, the M. marinum ESX-1 secretion system mediates sliding motility and is crucial for biofilm formation. These data provide new insight into M. marinum biofilm formation.}, } @article {pmid29898180, year = {2018}, author = {Coelho, A and Paula, A and Mota, M and Laranjo, M and Abrantes, M and Carrilho, F and Ferreira, M and Silva, M and Botelho, F and Carrilho, E}, title = {Dental caries and bacterial load in saliva and dental biofilm of type 1 diabetics on continuous subcutaneous insulin infusion.}, journal = {Journal of applied oral science : revista FOB}, volume = {26}, number = {}, pages = {e20170500}, pmid = {29898180}, issn = {1678-7765}, mesh = {Adult ; Bacterial Load ; *Biofilms/growth & development ; Case-Control Studies ; DNA, Bacterial ; Dental Caries/*microbiology ; Diabetes Mellitus, Type 1/*complications/*drug therapy ; Female ; Humans ; Hypoglycemic Agents/*administration & dosage ; Infusions, Subcutaneous ; Insulin/*administration & dosage ; Lactobacillus/isolation & purification/physiology ; Male ; Middle Aged ; Oral Hygiene ; Polymerase Chain Reaction ; Reference Values ; Risk Factors ; Saliva/metabolism/*microbiology ; Secretory Rate ; Statistics, Nonparametric ; Streptococcus/isolation & purification/physiology ; Young Adult ; }, abstract = {OBJECTIVES: Since most of the studies evaluates diabetics on multiple daily injections therapy and continuous subcutaneous insulin infusion may help gain better metabolic control and prevent complications, the objective of this study was to evaluate the prevalence of dental caries, the unstimulated salivary flow rate and the total bacteria load, Streptococcus spp. levels and Lactobacillus spp. levels in saliva and supragingival dental biofilm of type 1 diabetics on insulin pump.

MATERIAL AND METHODS: Sixty patients with type 1 diabetes on insulin pump and 60 nondiabetic individuals were included. The dental caries evaluation was performed using ICDAS and the oral hygiene was assessed according to Greene and Vermillion Simplified Oral Hygiene Index. Unstimulated saliva and supragingival dental biofilm were collected. Total bacteria, Streptococcus spp. and Lactobacillus spp. was quantified by qPCR.

RESULTS: Patients with type 1 diabetes had a higher prevalence of dental caries and filled and missing teeth when compared with the control group. These patients were associated with more risk factors for the development of dental caries, namely a lower unstimulated salivary flow rate and a higher bacterial load in saliva and dental biofilm.

CONCLUSION: Some risk factors related to dental caries were associated with type 1 diabetics. An early diagnosis combined with the evaluation of the risk profile of the diabetic patient is imperative, allowing the dental caries to be analyzed through a perspective of prevention and the patient to be integrated into an individualized oral health program.}, } @article {pmid29898109, year = {2018}, author = {Jin, C and Yu, Z and Peng, S and Feng, KE and Zhang, L and Zhou, X}, title = {The characterization and comparison of exopolysaccharides from two benthic diatoms with different biofilm formation abilities.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {90}, number = {2}, pages = {1503-1519}, doi = {10.1590/0001-3765201820170721}, pmid = {29898109}, issn = {1678-2690}, mesh = {Biofilms/*growth & development ; Diatoms/growth & development/*physiology ; Monosaccharides/chemistry/*metabolism ; Polysaccharides/*metabolism ; Uronic Acids/metabolism ; }, abstract = {Exopolysaccharide (EPS) of two benthic diatoms, Amphora sp. and Stauroneis sp., with different biofilm formation abilities were investigated. The ratio of suspension-cells/biofilm-cells was employed to indicate the diatom biofilm formation abilities. The soluble EPS from the supernatant of whole culture, tightly bound EPS from floating cells, loosely and tightly bound EPS from biofilm cells were fractionated as SL-EPS, F-TB-EPS, BF-LB-EPS and BF-TB-EPS, respectively. The analysis for productions and monosaccharide compositions indicated that EPS from two diatoms were different in terms of the productions, distributions, and monomer compositions. Amphora sp. produced more (1.5-fold) total exopolysaccharides, but less (<0.4-fold) BF-TB-EPS than Stauroneis sp. The monosaccharides of the EPS from Amphora sp. were more diverse than those of Stauroneis sp., with 13 and 10 monomers, respectively. Neutral sugars, Glc, Xyl and Man, were abundant in Stauroneis sp., while Gal, Glc and Xyl were rich in Amphora sp. Uronic acid and hexosamine were present in all fractions of two diatoms, especially Glc-A being the most abundant monomer in SL-EPS of Amphora sp. It was proposed that the high content of uronic acid (especially Glc-A) might be crucial for the strong biofilm formation abilities of Amphora sp.}, } @article {pmid29896189, year = {2018}, author = {Zhu, B and Song, L and Kong, X and Macleod, LC and Xu, P}, title = {A Novel Regulator Modulates Glucan Production, Cell Aggregation and Biofilm Formation in Streptococcus sanguinis SK36.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1154}, pmid = {29896189}, issn = {1664-302X}, support = {R01 DE018138/DE/NIDCR NIH HHS/United States ; R01 DE023078/DE/NIDCR NIH HHS/United States ; }, abstract = {Streptococcus sanguinis is an early colonizer of tooth surfaces and a key player in plaque biofilm development. However, the mechanism of biofilm formation of S. sanguinis is still unclear. Here, we showed that deletion of a transcription factor, brpL, promotes cell aggregation and biofilm formation in S. sanguinis SK36. Glucan, a polysaccharide synthesized from sucrose, was over-produced and aggregated in the biofilm of ΔbrpL, which was necessary for better biofilm formation ability of ΔbrpL. Quantitative RT-PCR demonstrated that gtfP was significantly up-regulated in ΔbrpL, which increased the productions of water-insoluble and water-soluble glucans. The ΔbrpLΔgtfP double mutant decreased biofilm formation ability of ΔbrpL to a level similar like that of ΔgtfP. Interestingly, the biofilm of ΔbrpL had an increased tolerance to ampicillin treatment, which might be due to better biofilm formation ability through the mechanisms of cellular and glucan aggregation. RNA sequencing and quantitative RT-PCR revealed the modulation of a group of genes in ΔbrpL was mediated by activating the expression of ciaR, another gtfP-related biofilm formation regulator. Double deletion of brpL and ciaR decreased biofilm formation ability to the phenotype of a ΔciaR mutant. Additionally, RNA sequencing elucidated a broad range of genes, related to carbohydrate metabolism and uptake, were activated in ΔbrpL. SSA_0222, a gene involved in the phosphotransferase system, was dramatically up-regulated in ΔbrpL and essential for S. sanguinis survival under our experimental conditions. In summary, brpL modulates glucan production, cell aggregation and biofilm formation by regulating the expression of ciaR in S. sanguinis SK36.}, } @article {pmid29893025, year = {2018}, author = {Davis, SC and Li, J and Gil, J and Valdes, J and Solis, M and Higa, A and Bowler, P}, title = {The wound-healing effects of a next-generation anti-biofilm silver Hydrofiber wound dressing on deep partial-thickness wounds using a porcine model.}, journal = {International wound journal}, volume = {15}, number = {5}, pages = {834-839}, pmid = {29893025}, issn = {1742-481X}, support = {//ConvaTec Ltd/ ; }, mesh = {Animals ; Anti-Infective Agents, Local/*therapeutic use ; *Bandages, Hydrocolloid ; Biofilms/*drug effects ; Humans ; Silver/*therapeutic use ; Swine ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; Wounds and Injuries/*therapy ; }, abstract = {Topical antimicrobials are widely used to control wound bioburden and facilitate wound healing; however, the fine balance between antimicrobial efficacy and non-toxicity must be achieved. This study evaluated whether an anti-biofilm silver-containing wound dressing interfered with the normal healing process in non-contaminated deep partial thickness wounds. In an in-vivo porcine wound model using 2 pigs, 96 wounds were randomly assigned to 1 of 3 dressing groups: anti-biofilm silver Hydrofiber dressing (test), silver Hydrofiber dressing (control), or polyurethane film dressing (control). Wounds were investigated for 8 days, and wound biopsies (n = 4) were taken from each dressing group, per animal, on days 2, 4, 6, and 8 after wounding and evaluated using light microscopy. No statistically significant differences were observed in the rate of reepithelialisation, white blood cell infiltration, angiogenesis, or granulation tissue formation following application of the anti-biofilm silver Hydrofiber dressing versus the 2 control dressings. Overall, epithelial thickness was similar between groups. Some differences in infiltration of specific cell types were observed between groups. There were no signs of tissue necrosis, fibrosis, or fatty infiltration in any group. An anti-biofilm silver Hydrofiber wound dressing did not cause any notable interference with normal healing processes.}, } @article {pmid29892109, year = {2018}, author = {Naik, MM and Naik, SP and Dubey, SK and Bhat, C and Charya, LS}, title = {Enhanced exopolysaccharide production and biofilm forming ability in methicillin resistant Staphylococcus sciuri isolated from dairy in response to acyl homoserine lactone (AHL).}, journal = {Journal of food science and technology}, volume = {55}, number = {6}, pages = {2087-2094}, pmid = {29892109}, issn = {0022-1155}, abstract = {Staphylococcus sciuri is an emerging human pathogen widely found in dairy industries. In this study, we have isolated methicillin resistant Staphylococcus sp. from biofilm formed on utensil used in the dairy society situated at Raia, Goa and was designated as NN14. The isolate NN14 was identified through 16S rRNA sequencing as S. sciuri (GenBank accession number MF621976). This report reveals that the S. sciuri strain NN14 responds positively to the, acyl-homoserine lactone (AHL) having 6-carbon long acyl chain i.e. N-hexanoyl-homoserine lactone molecule (C6-HSL) with gradual rise in their biofilm establishing potential as the concentration of AHL was increased from 250 nM, 500 nM to 1 µM when compared to control (without C6-HSL) by performing crystal violet assay using 48 well microtiter plate. Also, exopolysaccharide (EPS) production was found to increase with gradual increase in C6-HSL concentration from 250 nM, 500 nM to 1 µM proving potential role of EPS in biofilm formation. These results were further proved by scanning electron microscopy where increased in biofilm and EPS production with increase in C6-HSL concentration was observed. The biofilm forming capability of S. sciuri strain NN14 was found to decreased significantly when it was subjected to 10 µg/ml of (R)-2-(2-hydroxynaphthalen-1-yl)-thiazolidine-4-carboxylic acid, however with the addition of 250 and 500 nM, C6-HSL in presence of the antimicrobial compound (R)-2-(2-hydroxynaphthalen-1-yl)-thiazolidine-4-carboxylic acid, the biofilm development in bacterial strain NN14 was increased when compared with control. Our results demonstrated that the C6-HSL molecule neutralize the effect of antibacterial compound and enhances EPS production and biofilm development in S. sciuri.}, } @article {pmid29892084, year = {2018}, author = {Fünfhaus, A and Göbel, J and Ebeling, J and Knispel, H and Garcia-Gonzalez, E and Genersch, E}, title = {Swarming motility and biofilm formation of Paenibacillus larvae, the etiological agent of American Foulbrood of honey bees (Apis mellifera).}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {8840}, pmid = {29892084}, issn = {2045-2322}, mesh = {Animals ; Bacteriological Techniques ; Bees/*microbiology ; Biofilms/*growth & development ; Genotype ; Gram-Positive Bacterial Infections/microbiology/veterinary ; Lipopeptides/metabolism ; *Locomotion ; Paenibacillus larvae/classification/genetics/*physiology ; Staining and Labeling ; }, abstract = {American Foulbrood is a worldwide distributed, fatal disease of the brood of the Western honey bee (Apis mellifera). The causative agent of this fatal brood disease is the Gram-positive, spore-forming bacterium Paenibacillus larvae, which can be classified into four different genotypes (ERIC I-IV), with ERIC I and II being the ones isolated from contemporary AFB outbreaks. P. larvae is a peritrichously flagellated bacterium and, hence, we hypothesized that P. larvae is capable of coordinated and cooperative multicellular behaviors like swarming motility and biofilm formation. In order to analyze these behaviors of P. larvae, we firstly established appropriate functional assays. Using these assays we demonstrated that P. larvae ERIC II, but not P. larvae ERIC I, was capable of swarming. Swarming motility was hampered in a P. larvae ERIC II-mutant lacking production of paenilarvin, an iturin-like lipopeptide exclusively expressed by this genotype. Both genotypes were able to form free floating biofilm aggregates loosely attached to the walls of the culture wells. Visualizing the biofilms by Congo red and thioflavin S staining suggested structural differences between the biofilms formed. Biofilm formation was shown to be independent from paenilarvin production because the paenilarvin deficient mutant was comparably able to form a biofilm.}, } @article {pmid29891547, year = {2018}, author = {Wood, CR and Ohneck, EJ and Edelmann, RE and Actis, LA}, title = {A Light-Regulated Type I Pilus Contributes to Acinetobacter baumannii Biofilm, Motility, and Virulence Functions.}, journal = {Infection and immunity}, volume = {86}, number = {9}, pages = {}, pmid = {29891547}, issn = {1098-5522}, support = {R15 GM117478/GM/NIGMS NIH HHS/United States ; }, mesh = {A549 Cells ; Acinetobacter baumannii/*genetics/*pathogenicity ; Adhesins, Bacterial/genetics ; Animals ; Bacterial Adhesion ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Fimbriae, Bacterial/*genetics/radiation effects ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Humans ; Larva/microbiology ; *Light ; Moths ; Operon ; Temperature ; Virulence/genetics ; }, abstract = {Transcriptional analyses of Acinetobacter baumannii ATCC 17978 showed that the expression of A1S_2091 was enhanced in cells cultured in darkness at 24°C through a process that depended on the BlsA photoreceptor. Disruption of A1S_2091, a component of the A1S_2088-A1S_2091 polycistronic operon predicted to code for a type I chaperone/usher pilus assembly system, abolished surface motility and pellicle formation but significantly enhanced biofilm formation on plastic by bacteria cultured in darkness. Based on these observations, the A1S_2088-A1S_2091 operon was named the photoregulated pilus ABCD (prpABCD) operon, with A1S_2091 coding for the PrpA pilin subunit. Unexpectedly, comparative analyses of ATCC 17978 and prpA isogenic mutant cells cultured at 37°C showed the expression of light-regulated biofilm biogenesis and motility functions under a temperature condition that drastically affects BlsA production and its light-sensing activity. These assays also suggest that ATCC 17978 cells produce alternative light-regulated adhesins and/or pilus systems that enhance bacterial adhesion and biofilm formation at both 24°C and 37°C on plastic as well as on the surface of polarized A549 alveolar epithelial cells, where the formation of bacterial filaments and cell chains was significantly enhanced. The inactivation of prpA also resulted in a significant reduction in virulence when tested by using the Galleria mellonella virulence model. All these observations provide strong evidence showing the capacity of A. baumannii to sense light and interact with biotic and abiotic surfaces using undetermined alternative sensing and regulatory systems as well as alternative adherence and motility cellular functions that allow this pathogen to persist in different ecological niches.}, } @article {pmid29891387, year = {2018}, author = {D'Hondt, AS and Stock, W and Blommaert, L and Moens, T and Sabbe, K}, title = {Nematodes stimulate biomass accumulation in a multispecies diatom biofilm.}, journal = {Marine environmental research}, volume = {140}, number = {}, pages = {78-89}, doi = {10.1016/j.marenvres.2018.06.005}, pmid = {29891387}, issn = {1879-0291}, mesh = {Animals ; Biofilms/*growth & development ; Biomass ; Chlorophyll/metabolism ; Diatoms/*growth & development ; *Ecosystem ; Nematoda/*physiology ; }, abstract = {While the effects of abiotic parameters on microbial tidal biofilms are relatively well-documented, the effects of grazing and/or bioturbation by meiofauna are poorly understood. We investigated the impact of a natural nematode assemblage on the biomass and microbial community structure of a multispecies diatom biofilm. Nematodes stimulated diatom biomass accumulation of the biofilm and caused a shift in diatom community structure. Higher diatom biomass accumulation in the presence of nematodes could be the result of increased diatom biomass production through nutrient regeneration resulting from grazing or bioturbation, and/or through shifts in interspecific interactions between diatoms (e.g. competition) through selective grazing. Alternatively, lower biomass in the controls may be due to higher secretion of diatom production in the form of bound extracellular polymeric substances (EPS). Our observations underscore that meiobenthos, and especially nematodes, are important for the structure and production of tidal biofilms.}, } @article {pmid29890626, year = {2018}, author = {Borges, A and Simões, M and Todorović, TR and Filipović, NR and García-Sosa, AT}, title = {Cobalt Complex with Thiazole-Based Ligand as New Pseudomonas aeruginosa Quorum Quencher, Biofilm Inhibitor and Virulence Attenuator.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {6}, pages = {}, pmid = {29890626}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cobalt/*chemistry ; Ligands ; Luminescence ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Oligopeptides/biosynthesis ; Pseudomonas aeruginosa/*drug effects/pathogenicity/physiology ; Pyocyanine/biosynthesis ; *Quorum Sensing ; Thiazoles/chemistry/*pharmacology ; }, abstract = {Pseudomonas aeruginosa is one of the most dreaded human pathogens, because of its intrinsic resistance to a number of commonly used antibiotics and ability to form sessile communities (biofilms). Innovative treatment strategies are required and that can rely on the attenuation of the pathogenicity and virulence traits. The interruption of the mechanisms of intercellular communication in bacteria (quorum sensing) is one of such promising strategies. A cobalt coordination compound (Co(HL)2) synthesized from (E)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)-4-(p-tolyl)thiazole (HL) is reported herein for the first time to inhibit P. aeruginosa 3-oxo-C12-HSL-dependent QS system (LasI/LasR system) and underling phenotypes (biofilm formation and virulence factors). Its interactions with a possible target, the transcriptional activator protein complex LasR-3-oxo-C12-HSL, was studied by molecular modeling with the coordination compound ligand having stronger predicted interactions than those of co-crystallized ligand 3-oxo-C12-HSL, as well as known-binder furvina. Transition metal group 9 coordination compounds may be explored in antipathogenic/antibacterial drug design.}, } @article {pmid29890421, year = {2018}, author = {Xie, T and Yang, Q and Winkler, MKH and Wang, D and Zhong, Y and An, H and Chen, F and Yao, F and Wang, X and Wu, J and Li, X}, title = {Perchlorate bioreduction linked to methane oxidation in a membrane biofilm reactor: Performance and microbial community structure.}, journal = {Journal of hazardous materials}, volume = {357}, number = {}, pages = {244-252}, doi = {10.1016/j.jhazmat.2018.06.011}, pmid = {29890421}, issn = {1873-3336}, mesh = {Bacteria/genetics/metabolism ; Biofilms ; *Bioreactors ; Membranes, Artificial ; Methane/*metabolism ; Oxidation-Reduction ; Perchlorates/*metabolism ; RNA, Ribosomal, 16S ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Perchlorate bioreduction coupled to methane oxidation was successfully achieved without the addition of nitrate or nitrite in a membrane biofilm reactor (MBfR) inoculated with a mixture of freshwater sediments and anaerobic digester sludge as well as return activated sludge. The reactor was operated at different methane pressures (60, 40 and 20 Kpa) and influent perchlorate concentrations (1, 5 and 10 mg/L) to evaluate the biochemical process of perchlorate bioreduction coupled to methane oxidation. Perchlorate was completely reduced with a higher removal flux of 92.75 mg/m[2]·d using methane as the sole carbon source and electron donor, other than hydrogen or other limiting organics. Quantitative real-time PCR showed that bacteria prevailed over archaea and the abundances of mcrA, pMMO, pcrA, and nirS genes were correlated with the influent perchlorate flux. High-throughput sequencing of 16S rRNA genes demonstrated that the functional community consisted of methanotrophs, methylotrophs, perchlorate-reducing bacteria, as well as various denitrifiers.}, } @article {pmid29888724, year = {2018}, author = {Ulu, M and Pekbagriyanik, T and Ibis, F and Enhos, S and Ercan, UK}, title = {Antibiofilm efficacies of cold plasma and er: YAG laser on Staphylococcus aureus biofilm on titanium for nonsurgical treatment of peri-implantitis.}, journal = {Nigerian journal of clinical practice}, volume = {21}, number = {6}, pages = {758-765}, doi = {10.4103/njcp.njcp_261_17}, pmid = {29888724}, issn = {1119-3077}, mesh = {Biofilms/*drug effects/growth & development ; Cold Temperature ; Colony Count, Microbial ; Dental Implants/adverse effects/*microbiology ; Humans ; Lasers ; Lasers, Solid-State/*therapeutic use ; Microscopy, Electron, Scanning ; Peri-Implantitis/microbiology/*prevention & control ; Plasma Gases/chemistry/*pharmacology ; Staphylococcus aureus/drug effects/growth & development/physiology ; Surface Properties ; Titanium/*chemistry ; }, abstract = {OBJECTIVES: The aim of the present study was to compare antibiofilm efficacies of the laser in contact and noncontact application modes and cold atmospheric plasma (CAP) on Staphylococcus aureus biofilm grown on sandblasted, large grit, acid-etched (SLA) titanium discs as an in vitro model of biofilm eradication on dental implant materials.

METHODS: S. aureus biofilm was matured on titanium discs for 7 days then, treated with contact and noncontact Er:YAG laser and CAP. Antibiofilm efficacy of laser and plasma treatments were evaluated with colony counting and safranin assays. Surface characteristics of titanium disc were analyzed with scanning electron microscopy and surface roughness measurements. Temperature distribution over titanium discs were presented for the thermal safety assessment of laser and plasma treatments.

RESULTS: : CAP resulted in 6-log inactivation of S. aureus biofilm, whereas biofilm inactivation was determined as 1 and 2.7-log for noncontact and contact laser treatments, respectively. Laser and plasma treatments did not cause any alterations on the roughness of titanium discs. Contact laser treatment caused a focal temperature increase up to 58°C, whereas plasma treatment led a uniform temperature distribution on the disc within safe limits.

CONCLUSION: CAP showed superior antibiofilm activity on 7-day-old S. aureus biofilm grown over SLA titanium discs, compared to contact and noncontact laser treatment without temperature increase and any damage to the surface of titanium discs.}, } @article {pmid29888488, year = {2019}, author = {Barreto, JO and de Alencar-Silva, FJ and Oliveira, VC and Silva-Lovato, CH and Silva, PG and Regis, RR}, title = {The Effect of a Continuous Mechanical Polishing Protocol on Surface Roughness, Biofilm Adhesion, and Color Stability of Acrylic Resin Artificial Teeth.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {28}, number = {1}, pages = {e110-e117}, doi = {10.1111/jopr.12925}, pmid = {29888488}, issn = {1532-849X}, mesh = {Acrylic Resins/*therapeutic use ; *Bacterial Adhesion ; *Biofilms ; Candida albicans/growth & development ; *Dental Polishing/adverse effects/methods ; *Prosthesis Coloring ; Streptococcus mutans/growth & development ; Surface Properties ; *Tooth, Artificial ; }, abstract = {PURPOSE: Acrylic resin properties are susceptible to change over the duration of use, thereby decreasing prosthesis longevity. To make the material less susceptible to the action of external agents such as stain-causing liquids and cleaning solutions, polishing procedures are recommended. A specific mechanical polishing procedure performed regularly was evaluated regarding the biofilm adhesion, surface roughness (Ra), color stability (ΔE), and mass changes in acrylic resin artificial teeth.

MATERIALS AND METHODS: Sixty artificial teeth divided into two groups (n = 30) were immersed in distilled water (WT) and coffee (CF). These groups were then subdivided (n = 10) according to the type of polishing procedure administered: no polishing, biweekly polishing (once every 2 weeks) (pol 1), or monthly polishing (once a month) (pol 2), using aluminum oxide paste and a felt polishing wheel attached to an electric motor at a speed of 3000 rpm. Properties were evaluated at baseline and after 4, 8, 12, and 24 months of simulated immersion. At the end, the adhesion of Candida albicans and Streptococcus mutans multispecies biofilm in all groups was assessed.

RESULTS: The CF group showed an increased Ra and weight, and a significantly greater ΔE compared to the WT group. The polishing procedure reduced Ra and minimized the stains caused by coffee, without losing mass, with the biweekly regime more effective than the monthly regime. Also, polishing reduced the adhesion of biofilm in the CF groups, again with the biweekly regime the most effective.

CONCLUSIONS: When performed regularly, the mechanical polishing procedure tested reduces the changes in artificial teeth subjected to immersion in coffee, with the biweekly frequency most effective regarding the properties evaluated.}, } @article {pmid29887307, year = {2018}, author = {Dragoš, A and Kiesewalter, H and Martin, M and Hsu, CY and Hartmann, R and Wechsler, T and Eriksen, C and Brix, S and Drescher, K and Stanley-Wall, N and Kümmerli, R and Kovács, ÁT}, title = {Division of Labor during Biofilm Matrix Production.}, journal = {Current biology : CB}, volume = {28}, number = {12}, pages = {1903-1913.e5}, pmid = {29887307}, issn = {1879-0445}, support = {681295/ERC_/European Research Council/International ; 716734/ERC_/European Research Council/International ; BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/genetics/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Computational Biology ; Models, Biological ; *Phenotype ; Polysaccharides, Bacterial/genetics/metabolism ; Soil Microbiology ; }, abstract = {Organisms as simple as bacteria can engage in complex collective actions, such as group motility and fruiting body formation. Some of these actions involve a division of labor, where phenotypically specialized clonal subpopulations or genetically distinct lineages cooperate with each other by performing complementary tasks. Here, we combine experimental and computational approaches to investigate potential benefits arising from division of labor during biofilm matrix production. We show that both phenotypic and genetic strategies for a division of labor can promote collective biofilm formation in the soil bacterium Bacillus subtilis. In this species, biofilm matrix consists of two major components, exopolysaccharides (EPSs) and TasA. We observed that clonal groups of B. subtilis phenotypically segregate into three subpopulations composed of matrix non-producers, EPS producers, and generalists, which produce both EPSs and TasA. This incomplete phenotypic specialization was outperformed by a genetic division of labor, where two mutants, engineered as specialists, complemented each other by exchanging EPSs and TasA. The relative fitness of the two mutants displayed a negative frequency dependence both in vitro and on plant roots, with strain frequency reaching a stable equilibrium at 30% TasA producers, corresponding exactly to the population composition where group productivity is maximized. Using individual-based modeling, we show that asymmetries in strain ratio can arise due to differences in the relative benefits that matrix compounds generate for the collective and that genetic division of labor can be favored when it breaks metabolic constraints associated with the simultaneous production of two matrix components.}, } @article {pmid29886364, year = {2018}, author = {Dutta, K and Shityakov, S and Khalifa, I and Mal, A and Moulik, SP and Panda, AK and Ghosh, C}, title = {Effects of secondary carbon supplement on biofilm-mediated biodegradation of naphthalene by mutated naphthalene 1, 2-dioxygenase encoded by Pseudomonas putida strain KD9.}, journal = {Journal of hazardous materials}, volume = {357}, number = {}, pages = {187-197}, doi = {10.1016/j.jhazmat.2018.05.024}, pmid = {29886364}, issn = {1873-3336}, mesh = {Biodegradation, Environmental/drug effects ; Biofilms/*drug effects ; Carbon/pharmacology ; Dioxygenases/genetics/*metabolism ; Environmental Pollutants/*metabolism ; Multienzyme Complexes/genetics/*metabolism ; Mutation ; Naphthalenes/*metabolism ; Pseudomonas putida/*drug effects/physiology ; Sucrose/*pharmacology ; }, abstract = {Polycyclic aromatic hydrocarbons (PAHs) belong to a diverse group of environmental pollutants distributed ubiquitously in the environment. The carcinogenic properties of PAHs are the main causes of harm to human health. The green technology, biodegradation have become convenient options to address the environmental pollution. In this study, we analyzed the biodegradation potential of naphthalene with secondary carbon supplements (SCSs) in carbon deficient media (CSM) by Pseudomonas putida strain KD9 isolated from oil refinerary waste. The rigid-flexible molecular docking method revealed that the mutated naphthalene 1,2-dioxygenase had lower affinity for naphthalene than that found in wild type strain. Moreover, analytical methods (HPLC, qRT-PCR) and soft agar chemotaxis suggest sucrose (0.5 wt%) to be the best chemo-attractant and it unequivocally caused enhanced biodegradation of naphthalene (500 mg L[-1]) in both biofilm-mediated and shake-flask biodegradation methods. In addition, the morphological analysis detected from microscopy clearly showed KD9 to change its size and shape (rod to pointed) during biodegradation of naphthalene in CSM as sole source of carbon and energy. The forward versus side light scatter plot of the singlet cells obtained from flow cytometry suggests smaller cell size in CSM and lower florescence intensity of the total DNA content of cells. This study concludes that sucrose may be used as potential bio-stimulation agent.}, } @article {pmid29886334, year = {2018}, author = {Wu, N and Zeng, M and Zhu, B and Zhang, W and Liu, H and Yang, L and Wang, L}, title = {Impacts of different morphologies of anammox bacteria on nitrogen removal performance of a hybrid bioreactor: Suspended sludge, biofilm and gel beads.}, journal = {Chemosphere}, volume = {208}, number = {}, pages = {460-468}, doi = {10.1016/j.chemosphere.2018.06.012}, pmid = {29886334}, issn = {1879-1298}, mesh = {Ammonium Compounds/*metabolism ; Anaerobiosis ; Bacteria/*metabolism ; *Biofilms ; Bioreactors/*microbiology ; Denitrification ; Gels/*chemistry ; Nitrogen/*isolation & purification ; Oxidation-Reduction ; Sewage/microbiology ; Wastewater/*microbiology ; }, abstract = {The difficulties in the anaerobic ammonium oxidation (anammox) process mainly consist of low microbial growth rates and long start-up times of bioreactors. The morphologies of anammox bacteria might affect nitrogen removal performance and microbial community. In this study, three morphologies of anammox bacteria, namely, suspended sludge, biofilm and suspended sludge embedded in gel beads, were compared in a hybrid bioreactor under anoxic conditions (DO concentration < 0.1 mg L[-1]). The results show that the average total inorganic nitrogen removal efficiency of a hybrid bioreactor reached 67 ± 15% with a maximum value of 80% for continuous synthetic wastewater feeding, and that the specific total inorganic nitrogen removal rate reached 15.75 mg·(gVSS·h)[-1] regardless of the organic matter stress. Batch tests indicate that mainly suspended sludge (67%) and biofilm (26%) contributed to the anammox process, with the specific total inorganic nitrogen removal rate reaching 10.55 and 4.05 mg·(gVSS·h)[-1], respectively. However, the embedding of sludge in gel resulted in nitrification instead of anammox with a nitrification rate of 0.20 ± 0.01 mg·(L·h)[-1] due to the expansion of gel beads floating on the water surface. Therefore, a pore-forming technique was developed to produce more channels for gas dispersion inside the gel beads. In terms of microbial community, Candidatus Kuenenia involved in the anammox group was the most abundant genus in biofilm (43.4%) and suspended sludge (15.7%), while Nitrospira occupied the largest proportion in gel beads (25.6%). This study offers useful information for the selection of anammox bacteria morphology.}, } @article {pmid29886257, year = {2018}, author = {Tkhilaishvili, T and Di Luca, M and Abbandonato, G and Maiolo, EM and Klatt, AB and Reuter, M and Möncke-Buchner, E and Trampuz, A}, title = {Real-time assessment of bacteriophage T3-derived antimicrobial activity against planktonic and biofilm-embedded Escherichia coli by isothermal microcalorimetry.}, journal = {Research in microbiology}, volume = {169}, number = {9}, pages = {515-521}, doi = {10.1016/j.resmic.2018.05.010}, pmid = {29886257}, issn = {1769-7123}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriophage T3/pathogenicity/*physiology ; Biofilms/*growth & development ; Calorimetry/methods ; Computer Systems ; Escherichia coli/*physiology/*virology ; Microbial Sensitivity Tests ; }, abstract = {Bacterial biofilms, highly resistant to the conventional antimicrobial therapy, remain an unresolved challenge pressing the medical community to investigate new and alternative strategies to fight chronic implant-associated infections. Recently, strictly lytic bacteriophages have been revalued as powerful agents to kill antibiotic-resistant bacteria even in biofilm. Here, the interaction of T3 bacteriophage and planktonic and biofilm Escherichia coli TG1, respectively, was evaluated using isothermal microcalorimetry. Microcalorimetry is a non-invasive and highly sensitive technique measuring growth-related heat production of microorganisms in real-time. Planktonic and biofilm E. coli TG1 were exposed to different titers of T3 bacteriophage, ranging from 10[2] to 10[7] PFU/ml. The incubation of T3 with E. coli TG1 showed a strong inhibition of heat production both in planktonic and biofilm already at lower bacteriophage titers (10[3] PFU/ml). This method could be used to screen and evaluate the antimicrobial potential of different bacteriophages, alone and in combination with antibiotics in order to improve the treatment success of biofilm-associated infections.}, } @article {pmid29885800, year = {2018}, author = {Brilhante, RSN and Rocha, MGD and Guedes, GMM and Oliveira, JS and Araújo, GDS and España, JDA and Sales, JA and Aguiar, L and Paiva, MAN and Cordeiro, RA and Pereira-Neto, WA and Pinheiro, AQ and Sidrim, JJC and Castelo-Branco, DSCM and Rocha, MFG}, title = {Malassezia pachydermatis from animals: Planktonic and biofilm antifungal susceptibility and its virulence arsenal.}, journal = {Veterinary microbiology}, volume = {220}, number = {}, pages = {47-52}, doi = {10.1016/j.vetmic.2018.05.003}, pmid = {29885800}, issn = {1873-2542}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Bacterial Adhesion ; Biofilms/drug effects ; Caenorhabditis elegans ; Cat Diseases/microbiology ; Cats ; Dermatomycoses/microbiology/*veterinary ; Dog Diseases/microbiology ; Dogs ; Epithelial Cells/microbiology ; Fluconazole/pharmacology ; Foxes/microbiology ; Itraconazole/pharmacology ; Ketoconazole/pharmacology ; Malassezia/*drug effects/enzymology/isolation & purification/*pathogenicity ; Microbial Sensitivity Tests/methods ; Peptide Hydrolases/biosynthesis ; Phospholipases/biosynthesis ; Virulence ; }, abstract = {The yeast Malassezia pachydermatis is a component of the microbiota of dogs and cats, however it can cause otitis and seborrheic dermatitis in these animals. The objective of this study was to determine the antifungal susceptibility, and evaluate virulence and pathogenicity of 25 M. pachydermatis strains from animals. Susceptibility to ketoconazole, fluconazole, itraconazole, voriconazole, terbinafine, and amphotericin B was evaluated by broth microdilution assay. In addition, biofilm-forming ability, protease, phospholipase, hemolysin and melanin production and adhesion to epithelial cells by this yeast species were assessed. Finally, strain pathogenicity was investigated using the nematode Caenorhabditis elegans. Concerning the planktonic susceptibility, minimum inhibitory concentrations varied from <0.03 to>64 μg/mL for azole derivatives, 1 to >16 μg/mL for amphotericin B and 0.03 to 0.25 μg/mL for terbinafine. All strains were classified as strong biofilm producers, and ketoconazole, fluconazole and amphotericin B presented the best inhibitory effect against mature biofilms. All fungal isolates produced proteases, whereas 14/25 strains were positive for phospholipase production. Hemolytic activity was not observed and 18/25 strains showed dark pigmentation in the presence of L-DOPA. Regarding adhesion to epithelial cells, a low adhesion rate was observed in 10/12 evaluated strains. C. elegans mortality rate reached 95.9% after 96 h of exposure of the worms to M. pachydermatis. This yeast species produces important virulence factors and presents high pathogenicity, corroborating its clinical importance.}, } @article {pmid29885640, year = {2018}, author = {Souza, MGM and Leandro, LF and Moraes, TDS and Abrão, F and Veneziani, RCS and Ambrosio, SR and Martins, CHG}, title = {ent-Copalic acid antibacterial and anti-biofilm properties against Actinomyces naeslundii and Peptostreptococcus anaerobius.}, journal = {Anaerobe}, volume = {52}, number = {}, pages = {43-49}, doi = {10.1016/j.anaerobe.2018.05.013}, pmid = {29885640}, issn = {1095-8274}, mesh = {Actinomyces/*drug effects/physiology ; Biofilms/*drug effects ; Diterpenes/*pharmacology ; Fabaceae/chemistry ; Microbial Sensitivity Tests ; Peptostreptococcus/*drug effects/physiology ; Plant Extracts/*pharmacology ; }, abstract = {Diterpenes are an important class of plant metabolites that can be used in the search for new antibacterial agents. ent-Copalic acid (CA), the major diterpene in Copaifera species exudates, displays several pharmacological properties. This study evaluates the CA antibacterial potential against the anaerobic bacteria Peptostreptococcus anaerobius and Actinomyces naeslundii. Antimicrobial assays included time-kill and biofilm inhibition and eradication assays. Time-kill assays conducted for CA concentrations between 6.25 and 12.5 μg/mL evidenced bactericidal activity within 72 h. CA combined with chlorhexidine dihydrochloride (CHD) exhibited bactericidal action against P. anaerobius within 6 h of incubation. As for A. naeslundii, the same combination reduced the number of microorganisms by over 3 log10 at 24 h and exerted a bactericidal effect at 48 h of incubation. CA at 500 and 2000 μg/mL inhibited P. anaerobius and A. naeslundii biofilm formation by at least 50%, respectively. CA at 62.5 and 1.000 μg/mL eradicated 99.9% of pre-formed P. anaerobius and A. naeslundii biofilms, respectively. These results indicated that CA presents in vitro antibacterial activity and is a potential biofilm inhibitory agent. This diterpene may play an important role in the search for novel sources of agents that can act against anaerobic bacteria.}, } @article {pmid29885256, year = {2018}, author = {Lee, JH and Kim, YG and Lee, J}, title = {Inhibition of Candida albicans biofilm and hyphae formation by biocompatible oligomers.}, journal = {Letters in applied microbiology}, volume = {67}, number = {2}, pages = {123-129}, doi = {10.1111/lam.13016}, pmid = {29885256}, issn = {1472-765X}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida albicans/*drug effects/*pathogenicity ; Candidiasis/drug therapy/*prevention & control ; Caprolactam/*pharmacology ; Cell Aggregation/*drug effects ; Drug Resistance, Fungal ; Fluconazole/pharmacology ; Hyphae/drug effects/*growth & development ; Lactams/*pharmacology ; Microbial Sensitivity Tests ; Virulence ; }, abstract = {UNLABELLED: Candida albicans is a yeast pathogen known for its virulence and high morbidity rate, and it easily colonizes host tissues and implant devices and forms mature biofilms, which play an important role in pathogenesis and drug resistance. In this study, we investigated the abilities of thermoresponsive oligomers of N-vinylcaprolactam (OVCLs) to inhibit biofilm formation by C. albicans. One synthetic and four commercial OVCLs (≤MW 240 000) at a concentration of 5 μg ml[-1] were found to decrease C. albicans biofilm formation by more than 90% at 37°C, but to be less effective at 25°C. Microscopic observations showed that OVCLs clearly inhibited hyphal formation and cell aggregation by C. albicans, and this appeared to be responsible for their antibiofilm effects. In addition, effective antibiofouling coatings of OVCL/poly(lactic-co-glycolic acid) polymer blends were prepared on glass surfaces.

The emergence of multidrug-resistant Candida strains has prompted searches for new antifungals. The antibiofilm and antihyphae properties of OVCLs and OVCL coating against a fluconazole-resistant Candida albicans strain are present in this study. These findings suggest that OVCL and OVCL-coated biomaterials are potentially useful for controlling fungal biofilm formation by and the virulence of antifungal-resistant C. albicans.}, } @article {pmid29884758, year = {2018}, author = {Jiang, Q and Jin, Z and Sun, B}, title = {MgrA Negatively Regulates Biofilm Formation and Detachment by Repressing the Expression of psm Operons in Staphylococcus aureus.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {16}, pages = {}, pmid = {29884758}, issn = {1098-5336}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Electrophoretic Mobility Shift Assay ; *Gene Expression Regulation, Bacterial ; *Operon ; Staphylococcus aureus/*genetics/pathogenicity ; Transcription, Genetic ; Virulence ; Virulence Factors ; }, abstract = {Phenol-soluble modulins (PSMs) are amphipathic peptides that are produced by staphylococci and play important roles in Staphylococcus aureus biofilm formation and dissemination. Although the multiple functions of PSMs have been recognized, the regulatory mechanisms controlling the expression of psm operons remain largely unknown. In this study, we identified MgrA in a DNA pulldown assay and further demonstrated, by electrophoretic mobility shift assays and DNase I footprinting assays, that MgrA could bind specifically to the promoter regions of psm operons. We then constructed an isogenic mgrA deletion strain and compared biofilm formation and detachment in the wild-type and isogenic mgrA deletion strains. Our results indicated that biofilm formation and detachment were significantly increased in the mgrA mutant strain. Real-time quantitative reverse transcription-PCR data indicated that MgrA repressed the transcription of psm operons in cultures and biofilms, suggesting that MgrA is a negative regulator of psm expression. Furthermore, we analyzed biofilm formation by the psm mutant strains, and we found that PSMs promoted biofilm structuring and development in the mgrA mutant strain. These findings reveal that MgrA negatively regulates biofilm formation and detachment by repressing the expression of psm operons through direct binding to the psm promoter regions.IMPORTANCEStaphylococcus aureus is a human and animal pathogen that can cause biofilm-associated infections. PSMs have multiple functions in biofilm development and virulence in staphylococcal pathogenesis. This study has revealed that MgrA can negatively regulate psm expression by binding directly to the promoter regions of psm operons. Furthermore, our results show that MgrA can modulate biofilm structuring and development by repressing the production of PSMs in S. aureus Our findings provide novel insights into the regulatory mechanisms of S. aureus psm gene expression, biofilm development, and pathogenesis.}, } @article {pmid29883434, year = {2018}, author = {Haney, EF and Trimble, MJ and Cheng, JT and Vallé, Q and Hancock, REW}, title = {Critical Assessment of Methods to Quantify Biofilm Growth and Evaluate Antibiofilm Activity of Host Defence Peptides.}, journal = {Biomolecules}, volume = {8}, number = {2}, pages = {}, pmid = {29883434}, issn = {2218-273X}, support = {FDN-154287//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Defensins/*pharmacology ; Microbial Sensitivity Tests/*methods/standards ; Oligopeptides/pharmacology ; Pseudomonas aeruginosa/drug effects/physiology ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Biofilms are multicellular communities of bacteria that can adhere to virtually any surface. Bacterial biofilms are clinically relevant, as they are responsible for up to two-thirds of hospital acquired infections and contribute to chronic infections. Troublingly, the bacteria within a biofilm are adaptively resistant to antibiotic treatment and it can take up to 1000 times more antibiotic to kill cells within a biofilm when compared to planktonic bacterial cells. Identifying and optimizing compounds that specifically target bacteria growing in biofilms is required to address this growing concern and the reported antibiofilm activity of natural and synthetic host defence peptides has garnered significant interest. However, a standardized assay to assess the activity of antibiofilm agents has not been established. In the present work, we describe two simple assays that can assess the inhibitory and eradication capacities of peptides towards biofilms that are formed by both Gram-positive and negative bacteria. These assays are suitable for high-throughput workflows in 96-well microplates and they use crystal violet staining to quantify adhered biofilm biomass as well as tetrazolium chloride dye to evaluate the metabolic activity of the biofilms. The effect of media composition on the readouts of these biofilm detection methods was assessed against two strains of Pseudomonas aeruginosa (PAO1 and PA14), as well as a methicillin resistant strain of Staphylococcus aureus. Our results demonstrate that media composition dramatically alters the staining patterns that were obtained with these dye-based methods, highlighting the importance of establishing appropriate biofilm growth conditions for each bacterial species to be evaluated. Confocal microscopy imaging of P. aeruginosa biofilms grown in flow cells revealed that this is likely due to altered biofilm architecture under specific growth conditions. The antibiofilm activity of several antibiotics and synthetic peptides were then evaluated under both inhibition and eradication conditions to illustrate the type of data that can be obtained using this experimental setup.}, } @article {pmid29882939, year = {2018}, author = {Papetti, A and Signoretto, C and Spratt, DA and Pratten, J and Lingström, P and Zaura, E and Ofek, I and Wilson, M and Pruzzo, C and Gazzani, G}, title = {Components in Lentinus edodes mushroom with anti-biofilm activity directed against bacteria involved in caries and gingivitis.}, journal = {Food & function}, volume = {9}, number = {6}, pages = {3489-3499}, doi = {10.1039/c7fo01727h}, pmid = {29882939}, issn = {2042-650X}, mesh = {Actinomyces/*drug effects/physiology ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Chromatography, High Pressure Liquid ; Dental Caries/*microbiology ; Gingivitis/*microbiology ; Humans ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Prevotella intermedia/*drug effects/physiology ; Shiitake Mushrooms/*chemistry ; Streptococcus mutans/*drug effects/physiology ; Tandem Mass Spectrometry ; }, abstract = {The present study investigated the compounds present in the low molecular mass fraction of Lentinus edodes mushroom (shiitake) extract and their anti-virulence activity against oral pathogens (reference and clinical Streptococcus mutans, Actinomyces naeslundii, and Prevotella intermedia strains). Oxalic, succinic, and quinic acids, and adenine, inosine, and uridine were identified by HPLC-DAD-ESI-MS/MS. Their anti-biofilm production and preformed biofilm disaggregation activities were studied using commercial standard compounds at different concentrations. As regards S. mutans, the highest activity was shown by adenine at 5 mg mL-1 both in the biofilm inhibition (BI 50%) and biofilm disaggregation tests (BD 20%). Considering A. naeslundii, BI values close to 80% were registered for oxalic acid at 1 mg mL-1 and 2 mg mL-1 and BD 50% for quinic acid at 3 mg mL-1. A weaker activity was found against P. intermedia. Furthermore, different mixtures of the commercial standards were tested showing that the activity of a compound can be strongly and sometimes negatively affected by the presence of the other compounds.}, } @article {pmid29882774, year = {2018}, author = {Bellich, B and Lagatolla, C and Tossi, A and Benincasa, M and Cescutti, P and Rizzo, R}, title = {Influence of Bacterial Biofilm Polysaccharide Structure on Interactions with Antimicrobial Peptides: A Study on Klebsiella pneumoniae.}, journal = {International journal of molecular sciences}, volume = {19}, number = {6}, pages = {}, pmid = {29882774}, issn = {1422-0067}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cathelicidins/*pharmacology ; Cattle ; Escherichia coli/drug effects ; Escherichia coli Infections/microbiology ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/chemistry/*drug effects/*physiology ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/*chemistry ; }, abstract = {Balneotherapy is a clinically effective complementary approach in the treatment of low-grade inflammation- and stress-related pathologies. The biological mechanisms by which immersion in mineral-medicinal water and the application of mud alleviate symptoms of several pathologies are still not completely understood, but it is known that neuroendocrine and immunological responses—including both humoral and cell-mediated immunity—to balneotherapy are involved in these mechanisms of effectiveness; leading to anti-inflammatory, analgesic, antioxidant, chondroprotective, and anabolic effects together with neuroendocrine-immune regulation in different conditions. Hormesis can play a critical role in all these biological effects and mechanisms of effectiveness. The hormetic effects of balneotherapy can be related to non-specific factors such as heat—which induces the heat shock response, and therefore the synthesis and release of heat shock proteins—and also to specific biochemical components such as hydrogen sulfide (H2S) in sulfurous water and radon in radioactive water. Results from several investigations suggest that the beneficial effects of balneotherapy and hydrotherapy are consistent with the concept of hormesis, and thus support a role for hormesis in hydrothermal treatments.}, } @article {pmid29882414, year = {2018}, author = {Zhu, B and Macleod, LC and Kitten, T and Xu, P}, title = {Streptococcus sanguinis biofilm formation & interaction with oral pathogens.}, journal = {Future microbiology}, volume = {13}, number = {8}, pages = {915-932}, pmid = {29882414}, issn = {1746-0921}, support = {R01 DE023078/DE/NIDCR NIH HHS/United States ; R01 DE018138/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Dental Caries/*microbiology ; Endocarditis, Bacterial/microbiology ; Humans ; *Microbiota ; Streptococcus sanguis/genetics/*physiology ; }, abstract = {Caries and periodontitis are the two most common human dental diseases and are caused by dysbiosis of oral flora. Although commensal microorganisms have been demonstrated to protect against pathogens and promote oral health, most previous studies have addressed pathogenesis rather than commensalism. Streptococcus sanguinis is a commensal bacterium that is abundant in the oral biofilm and whose presence is correlated with health. Here, we focus on the mechanism of biofilm formation in S. sanguinis and the interaction of S. sanguinis with caries- and periodontitis-associated pathogens. In addition, since S. sanguinis is well known as a cause of infective endocarditis, we discuss the relationship between S. sanguinis biofilm formation and its pathogenicity in endocarditis.}, } @article {pmid29881840, year = {2018}, author = {Doroshenko, N and Rimmer, S and Hoskins, R and Garg, P and Swift, T and Spencer, HLM and Lord, RM and Katsikogianni, M and Pownall, D and MacNeil, S and Douglas, CWI and Shepherd, J}, title = {Antibiotic functionalised polymers reduce bacterial biofilm and bioburden in a simulated infection of the cornea.}, journal = {Biomaterials science}, volume = {6}, number = {8}, pages = {2101-2109}, doi = {10.1039/c8bm00201k}, pmid = {29881840}, issn = {2047-4849}, support = {MR/N501888/1/MRC_/Medical Research Council/United Kingdom ; MR/N501888/2/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Acrylic Resins/chemistry/*pharmacology ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Cornea/*drug effects/metabolism ; Lasers ; Microbial Sensitivity Tests ; Particle Size ; Reactive Oxygen Species/analysis/metabolism ; Staphylococcal Infections/*drug therapy/metabolism ; Staphylococcus aureus/cytology/*drug effects/metabolism ; Surface Properties ; Vancomycin/chemistry/*pharmacology ; }, abstract = {Microbial keratitis can arise from penetrating injuries to the cornea. Corneal trauma promotes bacterial attachment and biofilm growth, which decrease the effectiveness of antimicrobials against microbial keratitis. Improved therapeutic efficacy can be achieved by reducing microbial burden prior to antimicrobial therapy. This paper assesses a highly-branched poly(N-isopropyl acrylamide) with vancomycin end groups (HB-PNIPAM-van), for reducing bacterial attachment and biofilm formation. The polymer lacked antimicrobial activity against Staphylococcus aureus, but significantly inhibited biofilm formation (p = 0.0008) on plastic. Furthermore, pre-incubation of S. aureus cells with HB-PNIPAM-van reduced cell attachment by 50% and application of HB-PNIPAM-van to infected ex vivo rabbit corneas caused a 1-log reduction in bacterial recovery, compared to controls (p = 0.002). In conclusion, HB-PNIPAM-van may be a useful adjunct to antimicrobial therapy in the treatment of corneal infections.}, } @article {pmid29879711, year = {2019}, author = {Lima, CV and Tenuta, LMA and Cury, JA}, title = {Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study.}, journal = {Caries research}, volume = {53}, number = {1}, pages = {41-48}, doi = {10.1159/000489132}, pmid = {29879711}, issn = {1421-976X}, mesh = {Adolescent ; Adult ; Analysis of Variance ; *Biofilms ; Breakfast ; Cariostatic Agents/*administration & dosage ; Cooking/*methods ; Cross-Over Studies ; Double-Blind Method ; *Eating ; Female ; *Fluoridation ; Fluorides/*administration & dosage ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Osmolar Concentration ; Saliva/*chemistry ; Young Adult ; }, abstract = {Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 μg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p < 0.0001) and after meal ingestion (p < 0.04; salt > water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control.}, } @article {pmid29876607, year = {2018}, author = {Guan, Z and Wang, Y and Gao, L and Zhang, W and Lu, X}, title = {Effects of the histone-like protein HU on cellulose degradation and biofilm formation of Cytophaga hutchinsonii.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {15}, pages = {6593-6611}, doi = {10.1007/s00253-018-9071-9}, pmid = {29876607}, issn = {1432-0614}, support = {31770080//National Natural Science Foundation of China/ ; 31371262//National Natural Science Foundation of China/ ; }, mesh = {Bacterial Proteins/*genetics ; Bacteroidetes/genetics ; Biofilms/*growth & development ; Carbohydrate Metabolism ; Cellulase/metabolism ; Cellulose/*metabolism ; Cytophaga/*genetics/metabolism ; DNA-Binding Proteins/*genetics ; Escherichia coli/genetics ; Polymerase Chain Reaction ; }, abstract = {Cytophaga hutchinsonii, belonging to Bacteroidetes, is speculated to use a novel cell-contact mode to digest cellulose. In this study, we identified a histone-like protein HU, CHU_2750, in C. hutchinsonii, whose transcription could be induced by crystalline but not amorphous cellulose. We constructed a CHU_2750-deleted mutant and expressed CHU_2750 in Escherichia coli to study the gene's functions. Our results showed that although the deletion of CHU_2750 was not lethal to C. hutchinsonii, the mutant displayed an abnormal filamentous morphology, loose nucleoid, and obvious defects in the degradation of crystalline cellulose and cell motility. Further study indicated that the mutant displayed significantly decreased cell surface and intracellular endoglucanase activities but with β-glucosidase activities similar to the wild-type strain. Analyses by real-time quantitative PCR revealed that the transcription levels of many genes involved in cellulose degradation and/or cell motility were significantly downregulated in the mutant. In addition, we found that CHU_2750 was important for biofilm formation of C. hutchinsonii. The main extracellular components of the biofilm were analyzed, and the results showed that the mutant yielded significantly less exopolysaccharide but more extracellular DNA and protein than the wild-type strain. Collectively, our findings demonstrated that CHU_2750 is important for cellulose degradation, cell motility, and biofilm formation of C. hutchinsonii by modulating transcription of certain related genes, and it is the first identified transcriptional regulator in these processes of C. hutchinsonii. Our study shed more light on the mechanisms of cellulose degradation, cell motility, and biofilm formation by C. hutchinsonii.}, } @article {pmid29875567, year = {2018}, author = {Halkai, KR and Mudda, JA and Shivanna, V and Rathod, V and Halkai, R}, title = {Antibacterial Efficacy of Biosynthesized Silver Nanoparticles against Enterococcus faecalis Biofilm: An in vitro Study.}, journal = {Contemporary clinical dentistry}, volume = {9}, number = {2}, pages = {237-241}, pmid = {29875567}, issn = {0976-237X}, abstract = {AIM: This study aims to evaluate the antibacterial efficacy of biosynthesized silver nanoparticles (AgNPs) produced using the fungi against Enterococcus faecalis biofilm model on root dentin.

MATERIALS AND METHODS: AgNPs were biosynthesized using the fungi Fusarium semitectum isolated from healthy leaves of Withania somnifera. Minimum inhibitory concentration (MIC) of AgNPs was determined by microbroth dilution method using series of dilutions. MIC dose was standardized to evaluate the antibacterial efficacy. For biofilm model, thirty root dentin blocks prepared using human extracted single-rooted teeth were inoculated with E. faecalis in Trypticase soy agar broth for 2 weeks with alternate day replenishment and randomly divided into three groups (n = 10 each) and treated as: Group I: Sterile distilled water, Group II: AgNPs, and Group III: 2% chlorhexidine gluconate (CHX) and incubated at 37°C for 24 h. Each dentin block was rinsed in saline, vortex shaken for 60 s, and serial decimal dilutions were prepared and plated on trypticase soy agar plates and incubated for 24 h followed by CFU colony counting and statistically analyzed using one-way ANOVA followed by post hoc Tukey honestly significant difference test.

RESULTS: MIC of AgNPs for E. faecalis was determined as 30 mg/ml. No significant difference was seen between AgNPs and 2% CHX when compared to the control group with mean colony counts being 2.4, 2.5, and 6.77 CFU/ml (10[7]), respectively (P < 0.0001), against E. faecalis biofilm.

CONCLUSION: Biosynthesized AgNPs exhibit effective antimicrobial activity against E. faecalis biofilm on root dentin. Therefore, it can be employed as antimicrobial agent for root canal disinfection.}, } @article {pmid29874637, year = {2019}, author = {Nóbrega, DF and Leitão, TJ and Cury, JA and Tenuta, LMA}, title = {Fluoride Binding to Dental Biofilm Bacteria: Synergistic Effect with Calcium Questioned.}, journal = {Caries research}, volume = {53}, number = {1}, pages = {10-15}, doi = {10.1159/000488598}, pmid = {29874637}, issn = {1421-976X}, mesh = {Analysis of Variance ; Biofilms/*drug effects ; Calcium/*chemistry ; Calcium Fluoride/chemistry ; Cariostatic Agents/*chemistry ; Chemical Precipitation ; Dental Caries/microbiology/prevention & control ; Dental Enamel/*microbiology ; Drug Synergism ; Fluorides/*chemistry ; Humans ; Osmolar Concentration ; Regression Analysis ; Streptococcus mutans/*physiology ; }, abstract = {It has been suggested that fluoride binding to dental biofilm is enhanced when more bacterial calcium binding sites are available. However, this was only observed at high calcium and fluoride concentrations (i.e., when CaF2 precipitation may have occurred). We assessed fluoride binding to Streptococcus mutans pellets treated with calcium and fluoride at concentrations allowing CaF2 precipitation or not. Increasing calcium concentration resulted in a linear increase (p < 0.01) in fluoride concentration only in the pellets in which CaF2 precipitated. The results suggest that CaF2 precipitation, rather than bacterially bound fluoride, is responsible for the increase in fluoride binding to dental biofilm with the increase in calcium availability.}, } @article {pmid29874385, year = {2018}, author = {Conte, MP and Superti, F and Moio, M and Ammendolia, MG and Longhi, C and Aleandri, M and Marazzato, M and Goldoni, P and Parisi, P and Borab, Z and Palamara, AT and Carlesimo, B}, title = {Bacterial biofilm associated with a case of capsular contracture.}, journal = {The new microbiologica}, volume = {41}, number = {3}, pages = {238-241}, pmid = {29874385}, issn = {1121-7138}, mesh = {Adult ; Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/isolation & purification ; Bacterial Infections/*microbiology/pathology ; *Biofilms ; Breast Implants/*adverse effects ; Female ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Capsular contracture is one of the most common complications of implant-based breast augmentation. Despite its prevalence, the etiology of capsular contracture remains controversial although the surface texture of the breast implant, the anatomical position of the prosthesis and the presence of bacterial biofilm could be considered trigger factors. In fact, all medical implants are susceptible to bacterial colonization and biofilm formation. The present study demonstrated the presence of microbial biofilm constituted by cocci in a breast implant obtained from a patient with Baker grade II capsular contracture. This suggests that subclinical infection can be present and involved in low grade capsular contracture.}, } @article {pmid29873244, year = {2018}, author = {Oates, A and Lindsay, S and Mistry, H and Ortega, F and McBain, AJ}, title = {Modelling antisepsis using defined populations of facultative and anaerobic wound pathogens grown in a basally perfused biofilm model.}, journal = {Biofouling}, volume = {34}, number = {5}, pages = {507-518}, doi = {10.1080/08927014.2018.1466115}, pmid = {29873244}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Antisepsis/*methods ; Bacteroides fragilis/drug effects ; Bandages ; Biofilms/*drug effects/growth & development ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; *Models, Theoretical ; Pseudomonas aeruginosa/drug effects ; Streptococcus pyogenes/drug effects ; Wound Infection/*microbiology/prevention & control ; }, abstract = {An in vitro model was developed to assess the effects of topical antimicrobials on taxonomically defined wound biofilms. Biofilms were exposed over seven days to povidone-iodine, silver acetate or polyhexamethylene biguanide (PHMB) at concentrations used in wound dressings. The rank order of tolerance in multi-species biofilms, based on an analysis of the average bacterial counts over time was P. aeruginosa > methicillin-resistant Staphylococcus aureus (MRSA) > B. fragilis > S. pyogenes. The rank order of effectiveness for the antimicrobials in the biofilm model was povidone-iodine > PHMB > silver acetate. None of the test compounds eradicated P. aeruginosa or MRSA from the biofilms although all compounds except silver acetate eliminated S. pyogenes. Antimicrobial effectiveness against bacteria grown in multi-species biofilms did not correlate with planktonic susceptibility. Defined biofilm populations of mixed-species wound pathogens could be maintained in the basal perfusion model, facilitating the efficacy testing of treatments regimens and potential dressings against multi-species biofilms composed of wound isolates.}, } @article {pmid29870911, year = {2018}, author = {Cao, X and Wang, H and Zhang, S and Nishimura, O and Li, X}, title = {Azo dye degradation pathway and bacterial community structure in biofilm electrode reactors.}, journal = {Chemosphere}, volume = {208}, number = {}, pages = {219-225}, doi = {10.1016/j.chemosphere.2018.05.190}, pmid = {29870911}, issn = {1879-1298}, mesh = {Azo Compounds/*chemistry ; *Biodegradation, Environmental ; *Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Coloring Agents/*chemistry ; *Electrodes ; }, abstract = {In this study, the degradation pathway of the azo dye X-3B was explored in biofilm electrode reactors (BERs). The X-3B and chemical oxygen demand (COD) removal efficiencies were evaluated under different voltages, salinities, and temperatures. The removal efficiencies increased with increasing voltage. Additionally, the BER achieved maximum X-3B removal efficiencies of 66.26% and 75.27% at a NaCl concentration of 0.33 g L[-1] and temperature of 32 °C, respectively; it achieved a COD removal efficiency of 75.64% at a NaCl concentration of 0.330 g L[-1]. Fourier transform infrared spectrometry and gas chromatography-mass spectrometry analysis indicated that the X-3B biodegradation process first involved the interruption of the conjugated double-bond, resulting in aniline, benzodiazepine substance, triazine, and naphthalene ring formation. These compounds were further degraded into lower-molecular-weight products. From this, the degradation pathway of the azo dye X-3B was proposed in BERs. The relative abundances of the microbial community at the phylum and genus levels were affected by temperature, the presence of electrons, and an anaerobic environment in the BERs. To achieve better removal efficiencies, further studies on the functions of the microorganisms are needed.}, } @article {pmid29868829, year = {2018}, author = {Patras, KA and Derieux, J and Al-Bassam, MM and Adiletta, N and Vrbanac, A and Lapek, JD and Zengler, K and Gonzalez, DJ and Nizet, V}, title = {Group B Streptococcus Biofilm Regulatory Protein A Contributes to Bacterial Physiology and Innate Immune Resistance.}, journal = {The Journal of infectious diseases}, volume = {218}, number = {10}, pages = {1641-1652}, pmid = {29868829}, issn = {1537-6613}, mesh = {Animals ; Bacterial Proteins/*physiology ; Biofilms ; Cell Line ; Female ; Host-Pathogen Interactions/immunology/physiology ; Humans ; Immunity, Innate/*immunology ; Mice ; Neutrophils/immunology ; Streptococcal Infections/immunology/microbiology ; Streptococcus agalactiae/chemistry/*immunology/*pathogenicity/physiology ; }, abstract = {BACKGROUND: Streptococcus agalactiae (group B Streptococcus [GBS]) asymptomatically colonizes approximately 20% of adults; however, GBS causes severe disease in susceptible populations, including newborns, pregnant women, and elderly individuals. In shifting between commensal and pathogenic states, GBS reveals multiple mechanisms of virulence factor control. Here we describe a GBS protein that we named "biofilm regulatory protein A" (BrpA) on the basis of its homology with BrpA from Streptococcus mutans.

METHODS: We coupled phenotypic assays, RNA sequencing, human neutrophil and whole-blood killing assays, and murine infection models to investigate the contribution of BrpA to GBS physiology and virulence.

RESULTS: Sequence analysis identified BrpA as a LytR-CpsA-Psr enzyme. Targeted mutagenesis yielded a GBS mutant (ΔbrpA) with normal ultrastructural morphology but a 6-fold increase in chain length, a biofilm defect, and decreased acid tolerance. GBS ΔbrpA stimulated increased neutrophil reactive oxygen species and proved more susceptible to human and murine blood and neutrophil killing. Notably, the wild-type parent outcompeted ΔbrpA GBS in murine sepsis and vaginal colonization models. RNA sequencing of ΔbrpA uncovered multiple differences from the wild-type parent, including pathways of cell wall synthesis and cellular metabolism.

CONCLUSIONS: We propose that BrpA is an important virulence regulator and potential target for design of novel antibacterial therapeutics against GBS.}, } @article {pmid29868163, year = {2018}, author = {Jeong, D and Kim, DH and Song, KY and Seo, KH}, title = {Antimicrobial and anti-biofilm activities of Lactobacillus kefiranofaciens DD2 against oral pathogens.}, journal = {Journal of oral microbiology}, volume = {10}, number = {1}, pages = {1472985}, pmid = {29868163}, issn = {2000-2297}, abstract = {Background: Streptococcus mutans and Streptococcus sobrinus are major causative bacterial pathogens of dental caries. Objective: We investigated the applicability of three Lactobacillus strains (L. kefiranofaciens DD2, DD5, and DD6) isolated from kefir and three commercial Lactobacillus strains (L. plantarum ATCC 10,012, L. johnsonii JCM 1022, and L. rhamnosus ATCC 7469) as potential oral probiotics with respect to their survivability in an experimental oral environment, antimicrobial activity, and anti-biofilm formation activity against S. mutans and S. sobrinus. Results: Strains DD2, ATCC 10012, ATCC 7469, and JCM 1022 had the best oral survivability, including aerotolerance and enzymatic resistance, and inhibited the growth and biofilm formation of S. mutans and S. sobrinus. In particular, DD2 suppressed all three classes of biofilm formation-associated genes: those associated with carbohydrate metabolism and those encoding regulatory biofilm and adhesion proteins. Conclusions: These results indicate that the novel kefir isolate L. kefiranofaciens DD2 effectively and directly inhibits S. mutans and S. sobrinus.}, } @article {pmid29867886, year = {2018}, author = {Crespo, A and Blanco-Cabra, N and Torrents, E}, title = {Aerobic Vitamin B12 Biosynthesis Is Essential for Pseudomonas aeruginosa Class II Ribonucleotide Reductase Activity During Planktonic and Biofilm Growth.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {986}, pmid = {29867886}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a major pathogenic bacterium in chronic infections and is a model organism for studying biofilms. P. aeruginosa is considered an aerobic bacterium, but in the presence of nitrate, it also grows in anaerobic conditions. Oxygen diffusion through the biofilm generates metabolic and genetic diversity in P. aeruginosa growth, such as in ribonucleotide reductase activity. These essential enzymes are necessary for DNA synthesis and repair. Oxygen availability determines the activity of the three-ribonucleotide reductase (RNR) classes. Class II and III RNRs are active in the absence of oxygen; however, class II RNRs, which are important in P. aeruginosa biofilm growth, require a vitamin B12 cofactor for their enzymatic activity. In this work, we elucidated the conditions in which class II RNRs are active due to vitamin B12 concentration constraints (biosynthesis or environmental availability). We demonstrated that increased vitamin B12 levels during aerobic, stationary and biofilm growth activate class II RNR activity. We also established that the cobN gene is essentially responsible for B12 biosynthesis under planktonic and biofilm growth. Our results unravel the mechanisms of dNTP synthesis by P. aeruginosa during biofilm growth, which appear to depend on the bacterial strain (laboratory-type or clinical isolate).}, } @article {pmid29867813, year = {2018}, author = {Nielsen, DW and Klimavicz, JS and Cavender, T and Wannemuehler, Y and Barbieri, NL and Nolan, LK and Logue, CM}, title = {The Impact of Media, Phylogenetic Classification, and E. coli Pathotypes on Biofilm Formation in Extraintestinal and Commensal E. coli From Humans and Animals.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {902}, pmid = {29867813}, issn = {1664-302X}, abstract = {Extraintestinal pathogenic Escherichia coli (ExPEC) include avian pathogenic E. coli (APEC), neonatal meningitis E. coli (NMEC), and uropathogenic E. coli (UPEC) and are responsible for significant animal and human morbidity and mortality. This study sought to investigate if biofilm formation by ExPEC likely contributes to these losses since biofilms are associated with recurrent urinary tract infections, antibiotic resistance, and bacterial exchange of genetic material. Therefore, the goal of this study was to examine differences in biofilm formation among a collection of ExPEC and to ascertain if there is a relationship between their ability to produce biofilms and their assignment to phylogenetic groups in three media types - M63, diluted TSB, and BHI. Our results suggest that ExPEC produce relatively different levels of biofilm formation in the media tested as APEC (70.4%, p = 0.0064) and NMEC (84.4%, p = 0.0093) isolates were poor biofilm formers in minimal medium M63 while UPEC isolates produced significantly higher ODs under nutrient-limited conditions with 25% of strains producing strong biofilms in diluted TSB (p = 0.0204). Additionally, E. coli phylogenetic assignment using Clermont's original and revised typing scheme demonstrated significant differences among the phylogenetic groups in the different media. When the original phylogenetic group isolates previously typed as group D were phylogenetically typed under the revised scheme and examined, they showed substantial variation in their ability to form biofilms, which may explain the significant values of revised phylogenetic groups E and F in M63 (p = 0.0291, p = 0.0024). Our data indicates that biofilm formation is correlated with phylogenetic classification and subpathotype or commensal grouping of E. coli strains.}, } @article {pmid29865153, year = {2018}, author = {Vieira, ER and Xisto, MIDDS and Pele, MA and Alviano, DS and Alviano, CS and Barreto-Bergter, E and de Campos-Takaki, GM}, title = {Monohexosylceramides from Rhizopus Species Isolated from Brazilian Caatinga: Chemical Characterization and Evaluation of Their Anti-Biofilm and Antibacterial Activities.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {6}, pages = {}, pmid = {29865153}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Biomass ; Brazil ; Cerebrosides/chemistry/*isolation & purification/*pharmacology ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Microbial Sensitivity Tests ; Rhizopus/*chemistry ; Spectrometry, Mass, Electrospray Ionization ; }, abstract = {Monohexosylceramides (CMHs) are highly conserved fungal glycosphingolipids playing a role in several cellular processes such as growth, differentiation and morphological transition. In this study, we report the isolation, purification and chemical characterization of CMHs from Rhizopus stolonifer and R. microspores. Using positive ion mode ESI-MS, two major ion species were observed at m/z 750 and m/z 766, respectively. Both ion species consisted of a glucose/galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to a hydroxylated C16:0 fatty acid. The antimicrobial activity of CMH was evaluated against Gram positive and Gram negative bacteria using the agar diffusion assay. CMH from both Rhizopus species inhibited the growth of Bacillus terrae, Micrococcus luteus (M. luteus) and Pseudomonas stutzeri (P. stutzeri) with a MIC50 of 6.25, 6.25 and 3.13 mg/mL, respectively. The bactericidal effect was detected only for M. luteus and P. stutzeri, with MBC values of 25 and 6.25 mg/mL, respectively. Furthermore, the action of CMH on the biofilm produced by methicillin-resistant Staphylococcus aureus (MRSA) was analyzed using 12.5 and 25 mg/mL of CMH from R. microsporus. Total biofilm biomass, biofilm matrix and viability of the cells that form the biofilm structure were evaluated. CMH from R. microsporus was able to inhibit the MRSA biofilm formation in all parameters tested.}, } @article {pmid29864697, year = {2018}, author = {Santhakumari, S and Jayakumar, R and Logalakshmi, R and Prabhu, NM and Abdul Nazar, AK and Karutha Pandian, S and Veera Ravi, A}, title = {In vitro and in vivo effect of 2,6-Di-tert-butyl-4-methylphenol as an antibiofilm agent against quorum sensing mediated biofilm formation of Vibrio spp.}, journal = {International journal of food microbiology}, volume = {281}, number = {}, pages = {60-71}, doi = {10.1016/j.ijfoodmicro.2018.05.024}, pmid = {29864697}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/pharmacology ; Aquaculture ; *Biofilms ; Butylated Hydroxytoluene/*pharmacology ; Cyanobacteria/*chemistry/metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Quorum Sensing/genetics ; Vibrio/*drug effects ; }, abstract = {This study unveils the in vitro and in vivo antibiofilm potential of 2,6-Di-tert-butyl-4-methylphenol (DTBMP) from Chroococcus turgidus against Vibrio spp. In the preliminary study, cell free culture supernatant (CFCS) of C. turgidus inhibited the violacein production in biomarker strain Chromobacterium violaceum and its mutant strain CV026 in a dose dependent manner. The effective biofilm inhibitory concentration (BIC) of pure compound DTBMP from C. turgidus was identified as 250 μg/ml concentration in tested Vibrio species. Furthermore, DTBMP proved to effectively inhibit the bioluminescence production in V. harveyi and other biofilm related virulence traits such as exopolysaccharides (EPS) production, hydrophobicity index, swimming and swarming motility at its BIC concentration in three major pathogenic vibrios: V. harveyi, V. parahaemolyticus and V. vulnificus. The antibiofilm potential of DTBMP was validated through light, confocal laser scanning and scanning electron microscopic analyses. In addition, the non-bactericidal effect of DTBMP was determined through growth curve and 2,3-bis (2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Real-time PCR studies revealed the down-regulation of master quorum sensing (QS) regulator genes of V. harveyi such as luxR, luxS, luxP, luxQ and luxO on treatment with DTBMP. In vivo results confirmed that DTBMP augmented the survival rate of Litopenaeus vannamei larvae up to 75, 88 and 66% upon infection with V. harveyi, V. parahaemolyticus and V. vulnificus, respectively. The results of this study ascertain the promising effects of DTBMP as an antibiofilm agent, which could be positively explored to treat biofilm-associated vibrios infections in aquaculture.}, } @article {pmid29862210, year = {2018}, author = {Nasirmoghadas, P and Yadegari, S and Moghim, S and Esfahani, BN and Fazeli, H and Poursina, F and Hosseininassab, SA and Safaei, HG}, title = {Evaluation of Biofilm Formation and Frequency of Multidrug-resistant and Extended Drug-resistant Strain in Pseudomonas aeruginosa Isolated from Burn Patients in Isfahan.}, journal = {Advanced biomedical research}, volume = {7}, number = {}, pages = {61}, pmid = {29862210}, issn = {2277-9175}, abstract = {BACKGROUND: Pseudomonas aeruginosa is a biofilm-forming bacterium which can result in serious health problems, particularly in burn patients. Biofilm has been assumed to protect the bacteria from environmental fluctuations such as antimicrobial agent. Mucoid strains generate extensive levels of the alginate exopolysaccharide, which is an important factor of its biofilm.

MATERIALS AND METHODS: Totally, 100 isolates of P. aeruginosa has been gathered from wound infections of burn patients. Polymerase chain reaction of exoA gene has been carried out to confirm the bacteriologic identification of isolates. The biofilm-forming capacity has been specified by capsule staining and microtiter plate test as qualitative and quantitative determination, respectively. Antimicrobial susceptibility of the isolates has been specified by disk diffusion method.

RESULTS: All the isolates carried the exoA gene. The antibiotic resistance was imipenem (90%); levofloxacin (93%); aztreonam (87%); piperacillin-tazobactam (85%); tobramycin (92%); polymyxin b (PB) (2%); and ceftazidime (CAZ) (32%). Totally, multidrug-resistant (MDR) and extended drug-resistant (XDR) isolates were 19% and 75%, respectively. Fortunately, pan drug-resistant (PDR) strain has not been observed. The assessment of biofilm formation has shown that 7% of the isolates were nonbiofilm (N), weak (W) 67%, moderate (M) 22%, and strong (S) 4%.

CONCLUSIONS: As a result, the findings of this survey indicated that PB and CAZ were the most effective antibiotics against P. aeruginosa, which of course indicate a serious problem about the emergence of the PDR strains. There was no relationship between the patterns of biofilm production and antibiotic susceptibility, but high frequency of MDR/XDR and biofilm producer strains has been detected.}, } @article {pmid29861730, year = {2018}, author = {Heggendorn, FL and Fraga, AGM and Ferreira, DC and Gonçalves, LS and Lione, VOF and Lutterbach, MTS}, title = {Sulfate-Reducing Bacteria: Biofilm Formation and Corrosive Activity in Endodontic Files.}, journal = {International journal of dentistry}, volume = {2018}, number = {}, pages = {8303450}, pmid = {29861730}, issn = {1687-8728}, abstract = {AIM: This study describes the biofilm formation and the corrosive capacity of sulfate-reducing bacteria (SRB) on the metallic structure of used endodontic files.

METHODS: Sulfate-reducing bacteria (SRB) (Desulfovibrio desulfuricans oral and Desulfovibrio fairfieldensis or D. desulfuricans environmental) were inoculated into the culture media (Postgate C culture medium or modified Postgate E culture medium). The biocorrosive potential of these bacteria will be an important component of a biopharmaceutical under development called BACCOR. Afterwards, four used endodontic files (UEFs) were separately inoculated into a specific culture media for 445 days at 30°C in an incubator. The four UEFs were placed in a scanning electron microscope (SEM) and analyzed by the energy-dispersive X-ray spectrometry (EDS).

RESULTS: The confocal laser scanning microscopic images indicate the presence of biofilm in the four samples. The SEM and SEM-EDS revealed the presence of rough, irregular structures adhering along the metallic surface of the used endodontic files, suggesting a mature calcified biofilm with a high concentration of Ca, P, C, and S.

CONCLUSION: The formation of SRB biofilms on used endodontic files shows characteristics that may contribute to the biocorrosion of these files, and the results may also provide complementary data for a biopharmaceutical, which is still under development to assist in the removal of fractured endodontic files inside root channels.}, } @article {pmid29859892, year = {2018}, author = {Yang, Y and Li, Y and Gao, T and Zhang, Y and Wang, Q}, title = {C-di-GMP turnover influences motility and biofilm formation in Bacillus amyloliquefaciens PG12.}, journal = {Research in microbiology}, volume = {169}, number = {4-5}, pages = {205-213}, doi = {10.1016/j.resmic.2018.04.009}, pmid = {29859892}, issn = {1769-7123}, mesh = {3',5'-Cyclic-GMP Phosphodiesterases/*genetics/metabolism ; Bacillus amyloliquefaciens/genetics/*metabolism ; Biofilms/growth & development ; Biological Control Agents ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/*genetics/metabolism ; Gene Expression Regulation, Bacterial/*genetics ; Gene Knockout Techniques ; Movement ; Phosphorus-Oxygen Lyases/*genetics/metabolism ; Signal Transduction/genetics ; }, abstract = {Bis-(3'→5') cyclic dimeric guanosine monophosphate (c-di-GMP) is defined as a highly versatile secondary messenger in bacteria, coordinating diverse aspects of bacterial growth and behavior, including motility and biofilm formation. Bacillus amyloliquefaciens PG12 is an effective biocontrol agent against apple ring rot caused by Botryosphaeria dothidea. In this study, we characterized the core regulators of c-di-GMP turnover in B. amyloliquefaciens PG12. Using bioinformatic analysis, heterologous expression and biochemical characterization of knockout and overexpression derivatives, we identified and characterized two active diguanylate cyclases (which catalyze c-di-GMP biosynthesis), YhcK and YtrP and one active c-di-GMP phosphodiesterase (which degrades c-di-GMP), YuxH. Furthermore, we showed that elevating c-di-GMP levels up to a certain threshold inhibited the swimming motility of B. amyloliquefaciens PG12. Although yhcK, ytrP and yuxH knockout mutants did not display defects in biofilm formation, significant increases in c-di-GMP levels induced by YtrP or YuxH overexpression stimulated biofilm formation in B. amyloliquefaciens PG12. Our results indicate that B. amyloliquefaciens possesses a functional c-di-GMP signaling system that influences the bacterium's motility and ability to form biofilms. Since motility and biofilm formation influence the efficacy of biological control agent, our work provides a basis for engineering a more effective strain of B. amyloliquefaciens PG12.}, } @article {pmid29859586, year = {2018}, author = {de la Torre González, C and Huante-Guido, M and Velázquez Guadarrama, N and Preciado, D and Patiño López, G}, title = {Changes in biofilm in chronic cholesteatomatous otitis media in children following the application of sodium 2-mercaptoethanesulfonate (MESNA).}, journal = {International journal of pediatric otorhinolaryngology}, volume = {110}, number = {}, pages = {48-52}, doi = {10.1016/j.ijporl.2018.04.020}, pmid = {29859586}, issn = {1872-8464}, mesh = {Adult ; *Biofilms ; Child ; Child, Preschool ; Cholesteatoma, Middle Ear/*complications/*microbiology/surgery ; Chronic Disease ; Female ; Humans ; Male ; Mastoid/surgery ; Mesna/*therapeutic use ; Mexico ; Otitis Media/*complications/microbiology ; Pilot Projects ; Protective Agents/*therapeutic use ; }, abstract = {BACKGROUND: Pediatric cholesteatoma is a clinically challenging disease entity. Its biological behavior in the pediatric population differs from its behavior in adult population in terms of aggressiveness and recurrence. Several studies have shown the presence of biofilms associated with cholesteatoma that hinder the management and eradication of the infection. This led is to study the use of non-antimicrobial treatments impacting on the structure or composition of biofilms.

OBJECTIVE: To evaluate the changes that occur in the biofilm of cholesteatoma in pediatric patients after the application of sodium 2-mercaptoethanesulfonate (MESNA).

METHODS: A pilot study of 10 pediatric patients, with a median age of 10 years and a diagnosis of cholesteatomatous chronic otitis media, who underwent surgery for primary or revision mastoidectomy in the Otorhinolaryngology Service of the Hospital Infantil de México Federico Gómez between January 2016 and May 2017. During the surgery, basal samples of cholesteatoma and tissue were taken after topical application of 4% MESNA for 10 min. The samples were then processed for confocal laser microscopy.

RESULTS: In all samples structures compatible with bacterial biofilms were identified. The most relevant finding was the changes in the structure of the biofilm after the application of MESNA, such as disintegration and separation of the underlying tissue.

CONCLUSIONS: This is the first study that showing changes associated with cholesteatoma in the structure of the bacterial biofilm after the application of MESNA. The observed disintegration of cholesteatoma biofilm ultrastructure could aid in the management of the chronic infection associated with cholesteatoma.}, } @article {pmid29859290, year = {2018}, author = {Irani, N and Basardeh, E and Samiee, F and Fateh, A and Shooraj, F and Rahimi, A and Shahcheraghi, F and Vaziri, F and Masoumi, M and Pazhouhandeh, M and Siadat, SD and Kazemi-Lomedasht, F and Jamnani, FR}, title = {The inhibitory effect of the combination of two new peptides on biofilm formation by Acinetobacter baumannii.}, journal = {Microbial pathogenesis}, volume = {121}, number = {}, pages = {310-317}, doi = {10.1016/j.micpath.2018.05.051}, pmid = {29859290}, issn = {1096-1208}, mesh = {Acinetobacter baumannii/*drug effects/*physiology ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Biofilms/*drug effects ; Caco-2 Cells ; Humans ; Microbial Sensitivity Tests ; Peptides/*pharmacology ; Sequence Analysis, DNA ; }, abstract = {The emergence of extensively drug-resistant (XDR) Acinetobacter baumannii strains and the limited number of efficacious antibiotics demonstrate an urgent need to develop novel agents to treat infections caused by this dangerous pathogen. To find antimicrobial peptides against A. baumannii growing either in planktonic or in biofilm mode, biopanning was carried out with a peptide library on five XDR A. baumannii strains grown in the medium containing human blood (blood biopanning) and biofilms formed by these strains (biofilm biopanning). Two groups of peptides were identified, among which two peptides N10 (from blood biopanning) and NB2 (from biofilm biopanning) were selected and synthesized for more assessments. The selected peptides showed significant binding to A. baumannii rather than to the human cell line Caco-2. Both peptides were effective against A. baumannii and showed antibacterial activities (minimum inhibitory concentration (MIC) 500 μg/ml). In the biofilm inhibition assay, NB2 reduced biofilm more efficiently (75%) than N10 (50%). The combination of the two peptides could function better than each peptide alone to prevent biofilm formation by A. baumannii. Supplementation of conventional therapy with a mixture of peptides targeting A. baumannii or using peptides to deliver antibiotics specifically to the site of infection may be promising to control A. baumannii-related diseases.}, } @article {pmid29859115, year = {2018}, author = {Bahador, A and Farshadzadeh, Z and Raoofian, R and Mokhtaran, M and Pourakbari, B and Pourhajibagher, M and Hashemi, FB}, title = {Association of virulence gene expression with colistin-resistance in Acinetobacter baumannii: analysis of genotype, antimicrobial susceptibility, and biofilm formation.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {17}, number = {1}, pages = {24}, pmid = {29859115}, issn = {1476-0711}, support = {Grant No. 89. 01-30-10430//Tehran University of Medical Sciences and Health Services/ ; }, mesh = {Acinetobacter Infections/drug therapy/microbiology ; Acinetobacter baumannii/drug effects/*genetics/*pathogenicity ; Anti-Bacterial Agents/*therapeutic use ; Bacterial Outer Membrane Proteins/biosynthesis/genetics ; Bacterial Proteins/biosynthesis/genetics ; Biofilms/*growth & development ; Burns/microbiology ; Colistin/*therapeutic use ; DNA-Binding Proteins/biosynthesis/genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Humans ; Mannosyltransferases/biosynthesis/genetics ; Microbial Sensitivity Tests ; Rec A Recombinases/biosynthesis/genetics ; Virulence/genetics ; }, abstract = {BACKGROUND: Acinetobacter baumannii causes difficult-to-treat nosocomial infections, which often lead to morbidity due to the development of antimicrobial drug resistance and expression of virulence genes. Data regarding the association of resistance to colistin, a last treatment option, and the virulence gene expression of A. baumannii is scarce.

METHODS: We evaluated the MLVA genotype, antimicrobial resistance, and biofilm formation of 100 A. baumannii isolates from burn patients, and further compared the in vitro and in vivo expression of four virulence genes among five colistin-resistant A. baumannii (Cst-R-AB) isolates. Five Cst-R-AB isolates were tested; one from the present study, and four isolated previously.

RESULTS: Our results showed that reduced expression of recA, along with increased in vivo expression of lpsB, dnaK, and blsA; are associated with colistin resistance among Cst-R-AB isolates. Differences in virulence gene expressions among Cst-R-AB isolates, may in part explain common discrepant in vitro vs. in vivo susceptibility data during treatment of infections caused by Cst-R-AB.

CONCLUSIONS: Our findings highlight the intricate relationship between colistin-resistance and virulence among A. baumannii isolates, and underscore the importance of examining the interactions between virulence and antimicrobial resistance toward efforts to control the spread of multidrug-resistant A. baumannii (MDR-AB) isolates, and also to reduce disease severity in burn patients with MDR-AB infection.}, } @article {pmid29858724, year = {2018}, author = {Ramírez-Aldaba, H and Vázquez-Arenas, J and Sosa-Rodríguez, FS and Valdez-Pérez, D and Ruiz-Baca, E and Trejo-Córdoba, G and Escobedo-Bretado, MA and Lartundo-Rojas, L and Ponce-Peña, P and Lara, RH}, title = {Changes in biooxidation mechanism and transient biofilm characteristics by As(V) during arsenopyrite colonization with Acidithiobacillus thiooxidans.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {45}, number = {8}, pages = {669-680}, pmid = {29858724}, issn = {1476-5535}, support = {183230//CONACYT/ ; 205416//CONACYT/ ; }, mesh = {Acidithiobacillus thiooxidans/*metabolism ; Arsenic/chemistry ; Arsenicals/*chemistry ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Industrial Microbiology ; Iron/*chemistry ; Iron Compounds/*chemistry ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Minerals/*chemistry ; Oxygen/chemistry ; Spectrophotometry ; Spectrum Analysis, Raman ; Sulfides/*chemistry ; Surface Properties ; }, abstract = {Chemical and surface analyses are carried out using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM-EDS), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS) and extracellular surface protein quantification to thoroughly investigate the effect of supplementary As(V) during biooxidation of arsenopyrite by Acidithiobacillus thiooxidans. It is revealed that arsenic can enhance bacterial reactions during bioleaching, which can strongly influence its mobility. Biofilms occur as compact-flattened microcolonies, being progressively covered by a significant amount of secondary compounds (S n[2-] , S[0], pyrite-like). Biooxidation mechanism is modified in the presence of supplementary As(V), as indicated by spectroscopic and microscopic studies. GDS confirms significant variations between abiotic control and biooxidized arsenopyrite in terms of surface reactivity and amount of secondary compounds with and without As(V) (i.e. 6 μm depth). CLSM and protein analyses indicate a rapid modification in biofilm from hydrophilic to hydrophobic character (i.e. 1-12 h), in spite of the decrease in extracellular surface proteins in the presence of supplementary As(V) (i.e. stressed biofilms).}, } @article {pmid29857323, year = {2018}, author = {Hossain, MI and Paparini, A and Cord-Ruwisch, R}, title = {Direct oxygen uptake from air by novel glycogen accumulating organism dominated biofilm minimizes excess sludge production.}, journal = {The Science of the total environment}, volume = {640-641}, number = {}, pages = {80-88}, doi = {10.1016/j.scitotenv.2018.05.292}, pmid = {29857323}, issn = {1879-1026}, mesh = {Biofilms/*growth & development ; Bioreactors ; Glycogen/*metabolism ; Oxygen/*metabolism ; Sewage ; *Waste Disposal, Fluid ; }, abstract = {The cost associated with treatment and disposal of excess sludge produced is one of the greatest operational expenses in wastewater treatment plants. In this study, we quantify and explain greatly reduced excess sludge production in the novel glycogen accumulating organism (GAO) dominated drained biofilm system previously shown to be capable of extremely energy efficient removal of organic carbon (biological oxygen demand or BOD) from wastewater. The average excess sludge production rate was 0.05 g VSS g[-1] BOD (acetate) removed, which is about 9-times lower than that of comparative studies using the same acetate based synthetic wastewater. The substantially lower sludge yield was attributed to a number of features such as the high oxygen consumption facilitated by direct oxygen uptake from air, high biomass content (21.41 g VSS L[-1] of reactor), the predominance of the GAO (Candidatus competibacter) with a low growth yield and the overwhelming presence of the predatory protozoa (Tetramitus) in the biofilm. Overall, the combination of low-energy requirement for air supply (no compressed air supply) and the low excess sludge production rate, could make this novel "GAO drained biofilm" process one of the most economical ways of biological organic carbon removal from wastewater.}, } @article {pmid29857105, year = {2018}, author = {Volod'ko, AV and Davydova, VN and Nedashkovskaya, OI and Terentieva, NA and Chusovitin, EA and Galkin, NG and Yermak, IM}, title = {Morphology, electrokinetic characteristics and the effect on biofilm formation of carrageenan:chitosan polyelectrolyte complexes.}, journal = {International journal of biological macromolecules}, volume = {117}, number = {}, pages = {1118-1124}, doi = {10.1016/j.ijbiomac.2018.05.215}, pmid = {29857105}, issn = {1879-0003}, mesh = {Anti-Infective Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Carrageenan/*chemistry ; Chitosan/*chemistry ; Dynamic Light Scattering ; Microscopy, Atomic Force ; Polyelectrolytes/*chemistry ; }, abstract = {Carrageenan:chitosan (CG:CH) polyelectrolyte complexes (PEC) were obtained and the effect of the initial components ratio on formation was studied by dynamic light scattering, atomic force microscopy (AFM) and electrokinetic measurements. Positively charged PEC particles (average ζ-potential 40.2 mV) were formed, provided that the polycation was present in excess in the complex and was stabilized by chitosan amino groups. According to the AFM data, chitosan was located on the surface of the carrageenan fibers. In PEC where carrageenan prevailed, the number of unbound sulfate groups decreased when the chitosan content increased, this resulted in a decrease in the PEC negative surface charge (from -92.4 to -55.6 mV). In this case, AFM showed that chitosan was incorporated into the network structure of carrageenan and breaks it at a CG:CH ratio of 1:0.5 w/w. Complexes with a high content of kappa-CG inhibited biofilm formation by Gram negative and Gram positive microorganisms.}, } @article {pmid29856699, year = {2018}, author = {Contreras, L and Dal Piva, A and Ribeiro, FC and Anami, LC and Camargo, S and Jorge, A and Bottino, MA}, title = {Effects of Manufacturing and Finishing Techniques of Feldspathic Ceramics on Surface Topography, Biofilm Formation, and Cell Viability for Human Gingival Fibroblasts.}, journal = {Operative dentistry}, volume = {43}, number = {6}, pages = {593-601}, doi = {10.2341/17-126-L}, pmid = {29856699}, issn = {1559-2863}, mesh = {*Biofilms ; Candida albicans ; Cell Survival ; Ceramics/*pharmacology ; *Computer-Aided Design ; Dental Polishing/*methods ; Dental Porcelain ; Dental Veneers ; *Fibroblasts ; Gingiva/*cytology ; Humans ; In Vitro Techniques ; Materials Testing ; Microscopy, Electron, Scanning ; Stem Cells ; Streptococcus mutans ; Streptococcus sanguis ; Surface Properties ; }, abstract = {PURPOSE:: Feldspathic ceramic restorations can be obtained by different techniques (stratification or computer-aided design/computer-aided manufacturing [CAD/CAM] blocks) and finishing procedures (polishing or glaze application). This study evaluated the effects of techniques and finishing procedures on surface properties, biofilm formation, and viability of human gingival fibroblasts (FMM-1) in contact with these materials.

METHODS AND MATERIALS:: Ceramic specimens were obtained through a stratification technique (Vita VM9) and from CAD/CAM blocks (Vita Blocs Mark II; both Vita Zahnfabrik) and their surfaces were finished by polishing (ceramisté diamond rubbers + polishing paste; "p" subgroups) or glaze spray application + sintering ("g" subgroups). Roughness (Ra and RSm parameters) and surface free energy (SFE) were measured. Early biofilm formation of Streptococcus mutans, Streptococcus sanguinis, and Candida albicans was evaluated by counting colony-forming units (CFU). MTT (3-[4.5-dimethyl-thiazol-2-yl-]-2.5-diphenyl tetrazolium bromide) cytotoxicity test evaluated cellular viability for the growth of FMM-1 after 24 hours and seven days of contact. Scanning electron microscopy (SEM) and three-dimensional optical profilometry were performed to qualitatively analyze the surface. Data were analyzed by analysis of variance, Tukey test, and t-test (all α=0.05).

RESULTS:: Polished samples presented lower roughness (Ra, p=0.015; RSm, p=0.049) and higher SFE (p=0.00). Streptococci had higher CFU in all groups, but the CFU of C albicans was lower for polished samples. Biofilm formation was influenced by the interaction of all factors (p=0.018), and the materials showed no cytotoxicity to FMM-1 growth.

CONCLUSIONS:: Polishing resulted in the lowest values for surface roughness and higher SFE values. Polished ceramics showed less C albicans adherence while the adherence of Streptococci was greater than C albicans in all conditions.}, } @article {pmid29856510, year = {2018}, author = {Bjarnsholt, T and Buhlin, K and Dufrêne, YF and Gomelsky, M and Moroni, A and Ramstedt, M and Rumbaugh, KP and Schulte, T and Sun, L and Åkerlund, B and Römling, U}, title = {Biofilm formation - what we can learn from recent developments.}, journal = {Journal of internal medicine}, volume = {284}, number = {4}, pages = {332-345}, pmid = {29856510}, issn = {1365-2796}, support = {R21 AI137462/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Infective Agents/therapeutic use ; Bacterial Infections/*microbiology/therapy ; *Biofilms/drug effects/growth & development ; Biomedical Research ; Combined Modality Therapy ; Culture Media ; Extracellular Matrix/physiology ; Humans ; Opportunistic Infections/*microbiology/therapy ; Pseudomonas Infections/microbiology/therapy ; Pseudomonas aeruginosa/growth & development ; Staphylococcal Infections/microbiology/therapy ; Wound Infection/microbiology/therapy ; }, abstract = {Although biofilms have been observed early in the history of microbial research, their impact has only recently been fully recognized. Biofilm infections, which contribute to up to 80% of human microbial infections, are associated with common human disorders, such as diabetes mellitus and poor dental hygiene, but also with medical implants. The associated chronic infections such as wound infections, dental caries and periodontitis significantly enhance morbidity, affect quality of life and can aid development of follow-up diseases such as cancer. Biofilm infections remain challenging to treat and antibiotic monotherapy is often insufficient, although some rediscovered traditional compounds have shown surprising efficiency. Innovative anti-biofilm strategies include application of anti-biofilm small molecules, intrinsic or external stimulation of production of reactive molecules, utilization of materials with antimicrobial properties and dispersion of biofilms by digestion of the extracellular matrix, also in combination with physical biofilm breakdown. Although basic principles of biofilm formation have been deciphered, the molecular understanding of the formation and structural organization of various types of biofilms has just begun to emerge. Basic studies of biofilm physiology have also resulted in an unexpected discovery of cyclic dinucleotide second messengers that are involved in interkingdom crosstalk via specific mammalian receptors. These findings even open up new venues for exploring novel anti-biofilm strategies.}, } @article {pmid29856469, year = {2018}, author = {Miranda, PSD and Lannes-Costa, PS and Pimentel, BAS and Silva, LG and Ferreira-Carvalho, BT and Menezes, GC and Mattos-Guaraldi, AL and Hirata, R and Mota, RA and Nagao, PE}, title = {Biofilm formation on different pH conditions by Streptococcus agalactiae isolated from bovine mastitic milk.}, journal = {Letters in applied microbiology}, volume = {67}, number = {3}, pages = {235-243}, doi = {10.1111/lam.13015}, pmid = {29856469}, issn = {1472-765X}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Brazil ; Cattle ; Drug Resistance, Multiple, Bacterial ; Female ; Mastitis, Bovine/*microbiology ; Milk/chemistry/*microbiology ; Streptococcus agalactiae/drug effects/genetics/isolation & purification/*physiology ; }, abstract = {UNLABELLED: Streptococcus agalactiae is among the most relevant aetiologic agent of bovine clinical and subclinical mastitis, a major problem for the dairy industry. In Brazil, clonal diversity, capsular typing and multidrug resistance profiles of S. agalactiae related to human and bovine infections need further investigation. Presently, S. agalactiae isolates of bovine subclinical mastitis, from Brazilian Northeastern region, were submitted to capsular and pulsed-field gel electrophoresis (PFGE)-typing, antimicrobial susceptibility and assays of biofilm formation at different time incubation and pH levels. Sixteen bovine isolates were characterized by polymerase chain reaction assay as S. agalactiae capsular type II (CTII) and classified by PFGE in A1/A2 (n = 06), B1/B2 (n = 06), C (n = 03) and D (n = 01) patterns. Bovine S. agalactiae CTII strains were classified as 25% multidrug-resistant (MDR) with susceptibility to penicillin, linezolid and vancomycin. Biofilm formation on abiotic surface was strain- and time-dependent with significantly higher rates at pH 6·5. In conclusion, S. agalactiae capsular type II isolates recovered from bovine subclinical mastitis produced different pH-dependent biofilm levels. Our findings suggest that biofilm production is modulated by environmental factors and provides S. agalactiae advantageous in colonizing mammary gland during mastitis development, including MDR strains.

Streptococcus agalactiae is among the most relevant aetiologic agent of bovine clinical and subclinical mastitis, a major problem for the dairy industry. The disease may cause significant economic loss due to decreased production and milk quality and increased use of medicaments. Presently, data demonstrated that biofilm formation favours the establishment of infectious process in health mammary tissue by S. agalactiae and emphasizes that an acidic pH promotes adhesion by biofilm-forming bacterial strains. S. agalactiae strains (25%) showed resistance to tetracycline, azithromycin, erythromycin and clindamycin, and consequently were classified as multidrug-resistant strains.}, } @article {pmid29855854, year = {2018}, author = {Chakraborty, P and Joardar, S and Ray, S and Biswas, P and Maiti, D and Tribedi, P}, title = {3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz)-capped silver nanoparticles (TzAgNPs) inhibit biofilm formation of Pseudomonas aeruginosa: a potential approach toward breaking the wall of biofilm through reactive oxygen species (ROS) generation.}, journal = {Folia microbiologica}, volume = {63}, number = {6}, pages = {763-772}, pmid = {29855854}, issn = {1874-9356}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas Infections/metabolism/microbiology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Reactive Oxygen Species/*metabolism ; *Silver ; Virulence Factors ; }, abstract = {Microbial biofilms are factions of surface-colonized cells encompassed in a matrix of extracellular polymeric substances. Profound application of antibiotics in order to treat infections due to microbial biofilm has led to the emergence of several drug-resistant microbial strains. In this context, a novel type of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz)-capped silver nanoparticles (TzAgNPs) was synthesized, and efforts were given to test its antimicrobial and antibiofilm activities against Pseudomonas aeruginosa, a widely used biofilm-forming pathogenic organism. The synthesized TzAgNPs showed considerable antimicrobial activity wherein the MIC value of TzAgNPs was found at 40 μg/mL against Pseudomonas aeruginosa. Antibiofilm activity of TzAgNPs was also tested against Pseudomonas aeruginosa by carrying out an array of experiments like microscopic observation, crystal violet assay, and protein count using the sub-MIC doses of TzAgNPs. Since TzAgNPs showed efficient antibiofilm activity, thus, in the present study, efforts were put together to investigate the underlying cause of biofilm attenuation of Pseudomonas aeruginosa by using TzAgNPs. To this end, we discerned that the sub-MIC doses of TzAgNPs increased ROS level considerably in the bacterial cell. The result showed that the ROS level and microbial biofilm formation are inversely proportional. Thus, the attenuation in microbial biofilm could be attributed to the accumulation of ROS level. Furthermore, it was also duly noted that microorganisms upon treatment with TzAgNPs exhibited considerable diminution in virulence factors (protease and pyocyanin) in contrast to the control where the organisms were not treated with TzAgNPs. Thus, the results indicated that TzAgNPs exhibit considerable reduction in the development of biofilms and spreading of virulence factors. Taken together, all the results indicated that TzAgNPs could be deemed to be a promising agent for the prevention of microbial biofilm development that might assist to fight against infections linked to biofilm.}, } @article {pmid29855532, year = {2018}, author = {Arita-Morioka, KI and Yamanaka, K and Mizunoe, Y and Tanaka, Y and Ogura, T and Sugimoto, S}, title = {Inhibitory effects of Myricetin derivatives on curli-dependent biofilm formation in Escherichia coli.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {8452}, pmid = {29855532}, issn = {2045-2322}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*drug effects/growth & development ; Catechin/analogs & derivatives/pharmacology ; Escherichia coli/*physiology ; Flavonoids/chemistry/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Sigma Factor/genetics/metabolism ; }, abstract = {Biofilms are well-organised communities of microbes embedded in a self-produced extracellular matrix (e.g., curli amyloid fibers) and are associated with chronic infections. Therefore, development of anti-biofilm drugs is important to combat with these infections. Previously, we found that flavonol Myricetin inhibits curli-dependent biofilm formation by Escherichia coli (IC50 = 46.2 μM). In this study, we tested activities of seven Myricetin-derivatives to inhibit biofilm formation by E. coli K-12 in liquid culture. Among them, only Epigallocatechin gallate (EGCG), a major catechin in green tea, inhibited biofilm formation of K-12 (IC50 = 5.9 μM) more efficiently than Myricetin. Transmission electron microscopy and immunoblotting analyses demonstrated that EGCG prevented curli production by suppressing the expression of curli-related proteins. Quantitative RT-PCR analysis revealed that the transcripts of csgA, csgB, and csgD were significantly reduced in the presence of EGCG. Interestingly, the cellular level of RpoS, a stationary-phase specific alternative sigma factor, was reduced in the presence of EGCG, whereas the rpoS transcript was not affected. Antibiotic-chase experiments and genetic analyses revealed that EGCG accelerated RpoS degradation by ATP-dependent protease ClpXP in combination with its adaptor RssB. Collectively, these results provide significant insights into the development of drugs to treat chronic biofilm-associated infections.}, } @article {pmid29852465, year = {2018}, author = {Meng, Y and Yin, C and Zhou, Z and Meng, F}, title = {Increased salinity triggers significant changes in the functional proteins of ANAMMOX bacteria within a biofilm community.}, journal = {Chemosphere}, volume = {207}, number = {}, pages = {655-664}, doi = {10.1016/j.chemosphere.2018.05.076}, pmid = {29852465}, issn = {1879-1298}, mesh = {Bacteria/*metabolism ; Biofilms/*growth & development ; Proteomics/*methods ; *Salinity ; }, abstract = {Anaerobic ammonium oxidation (ANAMMOX) processes can potentially be influenced by salinity related to variable salinity in water environment. Here, we used 16S rRNA sequencing analysis combining with iTRAQ-based quantitative proteomic approach to reveal the response of microbial community and functional proteins to salinity, which was increased from 0 to 20 g L[-1] with a step of 5 g L[-1] (designed as S5, S10, S15 and S20) compared to control reactor (without salinity stress desined as S0). The 16S rRNA sequencing analysis showed that a high salinity (20 g L[-1], S20) decreased the abundance of genus Candidatus Jettenia but increased that of Candidatus Kuenenia. A total of 1609 differentially expressed proteins were acquired in the three comparison groups (S5:S0, S20:S0 and S20:S5). Of these, 39 proteins co-occurred in the three salt-exposed samples. Hydrazine dehydrogenase (HDH; Q1PW30) and nitrate reductase (Q1PZD8) were up-regulated more than 3-folds in the exposure of 20 g-NaCl/L. The functional enrichment analysis further showed that some proteins responsible for ion binding, catalysis and oxidation-reduction reaction were up-regulated, which explained the physiological resilience of ANAMMOX bacteria under salinity stress. Additionally, ANAMMOX bacteria responded to salinity by modulating the electron transport systems, indicating that the cells retained a high potential for proton pumping, as well as the ATP production. Furthermore, the over-expression of HDH which associated with ANAMMOX metabolism, was potentially related to the increased abundance of halophilic Candidatus Kuenenia. These findings provide a comprehensive baseline for understanding the roles of salinity stresses in shaping the functional proteins of ANAMMOX bacteria.}, } @article {pmid29850740, year = {2018}, author = {Morán, G and Ramos-Chagas, G and Hugelier, S and Xie, X and Boudjemaa, R and Ruckebusch, C and Sliwa, M and Darmanin, T and Gaucher, A and Prim, D and Godeau, G and Amigoni, S and Guittard, F and Méallet-Renault, R}, title = {Superhydrophobic polypyrene films to prevent Staphylococcus aureus and Pseudomonas aeruginosa biofilm adhesion on surfaces: high efficiency deciphered by fluorescence microscopy.}, journal = {Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology}, volume = {17}, number = {8}, pages = {1023-1035}, doi = {10.1039/c8pp00043c}, pmid = {29850740}, issn = {1474-9092}, mesh = {Bacterial Adhesion ; Biofilms/*drug effects ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; Polymers/chemistry/*pharmacology ; Pseudomonas aeruginosa/*physiology ; Pyrenes/*chemistry ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/*physiology ; Surface Properties ; }, abstract = {A blue luminescent and superhydrophobic coating based on an electropolymerized fluorinated-pyrene monomer and its planktonic bacteria and biofilm repellent properties are reported. Two different pathogenic bacterial strains (Gram-positive and Gram-negative) at two different incubation times (2 h planktonic bacterial and 24 h biofilm adhesion) were studied and monitored (analyzed) using multicolor scanning confocal fluorescence microscopy. The coating was proved to reduce bacterial adhesion by 65%. It is highly effective against biofilm attachment, with 90% reduction of bacteria surface coverage. This blue fluorescent surface provides a facile method to characterize the coating, observe the bacterial distribution and quantify the bacterial coverage rate by fluorescence imaging of different colors. Furthermore, the film does not show significant bacterial toxicity during the working incubation times.}, } @article {pmid29848761, year = {2018}, author = {Dingemans, J and Poudyal, B and Sondermann, H and Sauer, K}, title = {The Yin and Yang of SagS: Distinct Residues in the HmsP Domain of SagS Independently Regulate Biofilm Formation and Biofilm Drug Tolerance.}, journal = {mSphere}, volume = {3}, number = {3}, pages = {}, pmid = {29848761}, issn = {2379-5042}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; R01 GM123609/GM/NIGMS NIH HHS/United States ; R21 AI119726/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Substitution ; Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*drug effects/*growth & development ; DNA Mutational Analysis ; *Drug Tolerance ; *Gene Expression Regulation, Bacterial ; Mutagenesis, Site-Directed ; Protein Conformation ; Protein Domains ; Pseudomonas aeruginosa/*drug effects/genetics/*physiology ; }, abstract = {The formation of inherently drug-tolerant biofilms by the opportunistic pathogen Pseudomonas aeruginosa requires the sensor-regulator hybrid SagS, with ΔsagS biofilms being unstructured and exhibiting increased antimicrobial susceptibility. Recent findings indicated SagS to function as a switch to control biofilm formation and drug tolerance independently. Moreover, findings suggested the periplasmic sensory HmsP domain of SagS is likely to be the control point in the regulation of biofilm formation and biofilm cells transitioning to a drug-tolerant state. We thus asked whether specific amino acid residues present in the HmsP domain contribute to the switch function of SagS. HmsP domain residues were therefore subjected to alanine replacement mutagenesis to identify substitutions that block the sensory function(s) of SagS, which is apparent by attached cells being unable to develop mature biofilms and/or prevent transition to an antimicrobial-resistant state. Mutant analyses revealed 32 residues that only contribute to blocking one sensory function. Moreover, amino acid residues affecting attachment and subsequent biofilm formation but not biofilm tolerance also impaired histidine kinase signaling via BfiS. In contrast, residues affecting biofilm drug tolerance but not attachment and subsequent biofilm formation negatively impacted BrlR transcription factor levels. Structure prediction suggested the two sets of residues affecting sensory functions are located in distinct areas that were previously described as being involved in ligand binding interactions. Taken together, these studies identify the molecular basis for the dual regulatory function of SagS.IMPORTANCE The membrane-bound sensory protein SagS plays a pivotal role in P. aeruginosa biofilm formation and biofilm cells gaining their heightened resistance to antimicrobial agents, with SagS being the control point at which both pathways diverge. Here, we demonstrate for the first time that the two distinct pathways leading to biofilm formation and biofilm drug tolerance are under the control of two sets of amino acid residues located within the HmsP sensory domain of SagS. The respective amino acids are likely part of ligand binding interaction sites. Thus, our findings have the potential not only to enable the manipulation of SagS function but also to enable research of biofilm drug tolerance in a manner independent of biofilm formation (and vice versa). Moreover, the manipulation of SagS function represents a promising target/avenue open for biofilm control.}, } @article {pmid29848024, year = {2018}, author = {Olson, JK and Navarro, JB and Allen, JM and McCulloh, CJ and Mashburn-Warren, L and Wang, Y and Varaljay, VA and Bailey, MT and Goodman, SD and Besner, GE}, title = {An enhanced Lactobacillus reuteri biofilm formulation that increases protection against experimental necrotizing enterocolitis.}, journal = {American journal of physiology. Gastrointestinal and liver physiology}, volume = {315}, number = {3}, pages = {G408-G419}, pmid = {29848024}, issn = {1522-1547}, support = {R01 GM123482/GM/NIGMS NIH HHS/United States ; R41 GM122130/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Animals, Newborn ; Biofilms/growth & development ; Dextrans/pharmacology ; Drug Delivery Systems/*methods ; *Enterocolitis, Necrotizing/microbiology/prevention & control ; *Inflammation/drug therapy/microbiology ; *Intestines/drug effects/microbiology/physiopathology ; Limosilactobacillus reuteri/*physiology ; Microspheres ; Probiotics/*pharmacology ; Rats ; Rats, Sprague-Dawley ; }, abstract = {One significant drawback of current probiotic therapy for the prevention of necrotizing enterocolitis (NEC) is the need for at least daily administration because of poor probiotic persistence after enteral administration, increasing the risk of the probiotic bacteria causing bacteremia or sepsis if the intestines are already compromised. We previously showed that the effectiveness of Lactobacillus reuteri (Lr) in preventing NEC is enhanced when Lr is grown as a biofilm on the surface of dextranomer microspheres (DM). Here we sought to test the efficacy of Lr administration by manipulating the Lr biofilm state with the addition of biofilm-promoting substances (sucrose and maltose) to DM or by mutating the Lr gtfW gene (encoding an enzyme central to biofilm production). Using an animal model of NEC, we determined that Lr adhered to sucrose- or maltose-loaded DM significantly reduced histologic injury, improved host survival, decreased intestinal permeability, reduced intestinal inflammation, and altered the gut microbiome compared with Lr adhered to unloaded DM. These effects were abolished when DM or GtfW were absent from the Lr inoculum. This demonstrates that a single dose of Lr in its biofilm state decreases NEC incidence. Importantly, preloading DM with sucrose or maltose further enhances Lr protection against NEC in a GtfW-dependent fashion, demonstrating the tunability of the approach and the potential to use other cargos to enhance future probiotic formulations. NEW & NOTEWORTHY Previous clinical trials of probiotics to prevent necrotizing enterocolitis have had variable results. In these studies, probiotics were delivered in their planktonic, free-living form. We have developed a novel probiotic delivery system in which Lactobacillus reuteri (Lr) is delivered in its biofilm state. In a model of experimental necrotizing enterocolitis, this formulation significantly reduces intestinal inflammation and permeability, improves survival, and preserves the natural gut microflora compared with the administration of Lr in its free-living form.}, } @article {pmid29847738, year = {2018}, author = {Wu, YP and Bai, JR and Grosu, E and Zhong, K and Liu, LJ and Tang, MM and Huang, YN and Gao, H}, title = {Inhibitory Effect of 2R,3R-Dihydromyricetin on Biofilm Formation by Staphylococcus aureus.}, journal = {Foodborne pathogens and disease}, volume = {15}, number = {8}, pages = {475-480}, doi = {10.1089/fpd.2017.2405}, pmid = {29847738}, issn = {1556-7125}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Flavonols/*pharmacology ; Food Contamination/prevention & control ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Stainless Steel ; Staphylococcus aureus/*drug effects ; }, abstract = {The adherence and biofilm formation of Staphylococcus aureus on food contact surfaces are a major concern for the food industry. Development of antibiofilm agents from polyphenols has drawn much attention due to their potent activity. The present study explored the antibacterial and antibiofilm activities of 2R,3R-dihydromyricetin (DMY) against S. aureus ATCC 29213. It was found that DMY exerted excellent antibacterial and bactericidal properties against S. aureus with minimum inhibitory concentration and minimum bactericidal concentration values of 0.125 and 0.25 mg/mL, respectively. Crystal violet staining and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt reduction assay demonstrated that DMY significantly reduced the biofilm biomass of S. aureus and decreased the metabolic activity of biofilm cells. Micrographs of light microscope and scanning electron microscope confirmed that DMY inhibited the biofilm formation and caused a disintegration of the complex biofilm architecture. Moreover, DMY was highly efficient in reducing the number of sessile S. aureus cells adhered to stainless steel. These results suggested that DMY could have potential application to control S. aureus contamination in a food processing environment.}, } @article {pmid29846772, year = {2018}, author = {Danikowski, KM and Cheng, T}, title = {Alkaline Phosphatase Activity of Staphylococcus aureus Grown in Biofilm and Suspension Cultures.}, journal = {Current microbiology}, volume = {75}, number = {9}, pages = {1226-1230}, pmid = {29846772}, issn = {1432-0991}, mesh = {Alkaline Phosphatase/antagonists & inhibitors/*metabolism ; Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; Deoxyribonucleases/pharmacology ; Microbial Sensitivity Tests ; Staphylococcus aureus/drug effects/*enzymology/*physiology ; Vanadates/pharmacology ; }, abstract = {Staphylococcus aureus is known for its resistance to antibiotic treatment as well as the ability to form biofilms. Biofilm formation has been seen in S. aureus infections, yet, the mechanism of biofilm formation is not completely understood. Many molecules, such as DNA and polysaccharides, have been identified in the biofilm microenvironment, but little is known about the enzymes involved in the process. In this paper, alkaline phosphatase (ALP) activity was investigated in S. aureus grown either in biofilm or suspension cultures, achieved using DNase I. A significant increase of ALP activity was observed in S. aureus biofilm culture compared to its suspension counterpart. Treatment of sodium orthovanadate, an ALP inhibitor, significantly decreased biofilm formation. Its inhibition was on par with DNase I treatment at specific doses. Thus, ALP may play an important role in the biofilm formation. Likewise, ALP inhibition may be a novel target for anti-biofilm therapeutics.}, } @article {pmid29846088, year = {2018}, author = {Liu, Q and Zheng, Z and Kim, W and Burgwyn Fuchs, B and Mylonakis, E}, title = {Influence of subinhibitory concentrations of NH125 on biofilm formation & virulence factors of Staphylococcus aureus.}, journal = {Future medicinal chemistry}, volume = {10}, number = {11}, pages = {1319-1331}, pmid = {29846088}, issn = {1756-8927}, support = {P01 AI083214/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Coagulase/metabolism ; Deoxyribonucleases/metabolism ; Enzyme Activation ; Hemolysin Proteins/metabolism ; Humans ; Imidazoles/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/metabolism ; Microbial Sensitivity Tests ; Staphylococcal Infections ; Virulence ; Virulence Factors/*metabolism ; }, abstract = {AIM: l-benzyl-3-cetyl-2-methylimidazolium iodide (NH125) can inhibit Staphylococcus aureus growth. We investigated the effects of sub-MIC concentrations of NH125 on S. aureus biofilm and virulence. Methodology & results: Three strains of S. aureus were tested. Sub-lethal concentrations of NH125 repressed biofilm formation. At partial sub-MICs, NH125 downregulated the expression of most virulence, while strain-dependent effects were found in the production of α-hemolysin, δ-hemolysin, coagulase and nuclease. In Galleria mellonella model, methicillin-resistant S. aureus pre-exposed to NH125 demonstrated significantly lower killing (p = 0.032 for 1/16 and 1/8 MICs; 0.008 for 1/4 MIC; and 0.001 for 1/2 MIC).

CONCLUSION: Sub-MIC concentrations of NH125 inhibited biofilm formation and virulence of S. aureus. These findings provide further support for evaluating the clinical efficacy of NH125 in staphylococcal infection.}, } @article {pmid29845096, year = {2018}, author = {Sharif Hossain, ABM and Uddin, MM and Fawzi, M and Veettil, VN}, title = {Nano-cellulose biopolymer based nano-biofilm biomaterial using plant biomass: An innovative plant biomaterial dataset.}, journal = {Data in brief}, volume = {17}, number = {}, pages = {1245-1252}, pmid = {29845096}, issn = {2352-3409}, abstract = {The nano-cellulose derived nano-biofilm keeps a magnificent role in medical, biomedical, bioengineering and pharmaceutical industries. Plant biomaterial is naturally organic and biodegradable. This study has been highlighted as one of the strategy introducing biomass based nano-bioplastic (nanobiofilm) to solve dependency on petroleum and environment pollution because of non-degradable plastic. The data study was carried out to investigate the nano-biopolymer (nanocellulose) based nano-biofilm data from corn leaf biomass coming after bioprocess technology without chemicals. Corn leaf biomass was used to produce biodegradable nano-bioplastic for medical and biomedical and other industrial uses. Data on water absorption, odor, pH, cellulose content, shape and firmness, color coating and tensile strength test have been exhibited under standardization of ASTM (American standard for testing and materials). Moreover, the chemical elements of nanobiofilm like K[+], CO3[--], Cl[-], Na[+] showed standard data using the EN (166).}, } @article {pmid29844920, year = {2018}, author = {Bao, K and Bostanci, N and Thurnheer, T and Grossmann, J and Wolski, WE and Thay, B and Belibasakis, GN and Oscarsson, J}, title = {Aggregatibacter actinomycetemcomitans H-NS promotes biofilm formation and alters protein dynamics of other species within a polymicrobial oral biofilm.}, journal = {NPJ biofilms and microbiomes}, volume = {4}, number = {}, pages = {12}, pmid = {29844920}, issn = {2055-5008}, abstract = {Aggregatibacter actinomycetemcomitans is a Gram-negative organism, strongly associated with aggressive forms of periodontitis. An important virulence property of A. actinomycetemcomitans is its ability to form tenacious biofilms that can attach to abiotic as well as biotic surfaces. The histone-like (H-NS) family of nucleoid-structuring proteins act as transcriptional silencers in many Gram-negative bacteria. To evaluate the role of H-NS in A. actinomycetemcomitans, hns mutant derivatives of serotype a strain D7S were generated. Characteristics of the hns mutant phenotype included shorter and fewer pili, and substantially lower monospecies biofilm formation relative to the wild type. Furthermore, the D7S hns mutant exhibited significantly reduced growth within a seven-species oral biofilm model. However, no apparent difference was observed regarding the numbers and proportions of the remaining six species regardless of being co-cultivated with D7S hns or its parental strain. Proteomics analysis of the strains grown in monocultures confirmed the role of H-NS as a repressor of gene expression in A. actinomycetemcomitans. Interestingly, proteomics analysis of the multispecies biofilms indicated that the A. actinomycetemcomitans wild type and hns mutant imposed different regulatory effects on the pattern of protein expression in the other species, i.e., mainly Streptococcus spp., Fusobacterium nucleatum, and Veillonella dispar. Gene ontology analysis revealed that a large portion of the differentially regulated proteins was related to translational activity. Taken together, our data suggest that, apart from being a negative regulator of protein expression in A. actinomycetemcomitans, H-NS promotes biofilm formation and may be an important factor for survival of this species within a multispecies biofilm.}, } @article {pmid29843904, year = {2018}, author = {Moraes, JO and Cruz, EA and Souza, EGF and Oliveira, TCM and Alvarenga, VO and Peña, WEL and Sant'Ana, AS and Magnani, M}, title = {Predicting adhesion and biofilm formation boundaries on stainless steel surfaces by five Salmonella enterica strains belonging to different serovars as a function of pH, temperature and NaCl concentration.}, journal = {International journal of food microbiology}, volume = {281}, number = {}, pages = {90-100}, doi = {10.1016/j.ijfoodmicro.2018.05.011}, pmid = {29843904}, issn = {1879-3460}, mesh = {Bacterial Adhesion/drug effects/*physiology ; *Biofilms ; Hydrogen-Ion Concentration ; Salmonella enterica/classification/drug effects/*physiology ; Serogroup ; *Sodium Chloride/pharmacology ; Species Specificity ; *Stainless Steel ; *Temperature ; }, abstract = {This study aimed to assess the capability of 97 epidemic S. enterica strains belonging to 18 serovars to form biofilm. Five strains characterized as strong biofilm-producers, belonging to distinct serovars (S. Enteritidis 132, S. Infantis 176, S. Typhimurium 177, S. Heidelberg 281 and S. Corvallis 297) were assayed for adhesion/biofilm formation on stainless steel surfaces. The experiments were conducted in different combinations of NaCl (0, 2, 4, 5, 6, 8 and 10% w/v), pH (4, 5, 6 and 7) and temperatures (8 °C, 12 °C, 20 °C and 35 °C). Only adhesion was assumed to occur when S. enterica counts were ≥3 and <5 log CFU/cm[2], whereas biofilm formation was defined as when the counts were ≥5 log CFU/cm[2]. The binary responses were used to develop models to predict the probability of adhesion/biofilm formation on stainless steel surfaces by five strains belonging to different S. enterica serovars. A total of 99% (96/97) of the tested S. enterica strains were characterized as biofilm-producers in the microtiter plate assays. The ability to form biofilm varied (P < 0.05) within and among the different serovars. Among the biofilm-producers, 21% (20/96), 45% (43/96), and 35% (34/96) were weak, moderate and strong biofilm-producers, respectively. The capability for adhesion/biofilm formation on stainless steel surfaces under the experimental conditions studied varied among the strains studied, and distinct secondary models were obtained to describe the behavior of the five S. enterica tested. All strains showed adhesion at pH 4 up to 4% of NaCl and at 20 °C and 35 °C. The probability of adhesion decreased when NaCl concentrations were >8% and at 8 °C, as well as in pH values ≤ 5 and NaCl concentrations > 6%, for all tested strains. At pH 7 and 6, biofilm formation for S. Enteritidis, S. Infantis, S. Typhimurium, S. Heidelberg was observed up to 6% of NaCl at 35 °C and 20 °C. The predicted boundaries for adhesion were pH values < 5 and NaCl ≥ 4% and at temperatures <20 °C. For biofilm formation, the predicted boundaries were pH values < 5 and NaCl concentrations ≥ 2% and at temperatures <20 °C for all strains. The secondary models obtained describe the variability in boundaries of adhesion and biofilm formation on stainless steel by five strains belonging to different S. enterica serovars. The boundary models can be used to predict adhesion and biofilm formation ability on stainless steel by S. enterica as affected by pH, NaCl and temperature.}, } @article {pmid29843448, year = {2018}, author = {Koziróg, A and Otlewska, A and Brycki, B}, title = {Viability, Enzymatic and Protein Profiles of Pseudomonas aeruginosa Biofilm and Planktonic Cells after Monomeric/Gemini Surfactant Treatment.}, journal = {Molecules (Basel, Switzerland)}, volume = {23}, number = {6}, pages = {}, pmid = {29843448}, issn = {1420-3049}, mesh = {Alkenes/pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Plankton/*drug effects ; Pseudomonas aeruginosa/drug effects/*physiology ; Quaternary Ammonium Compounds/pharmacology ; Surface-Active Agents/*pharmacology ; }, abstract = {This study set out to investigate the biological activity of monomeric surfactants dodecyltrimethylammonium bromide (DTAB) and the next generation gemini surfactant hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C6) against the environmental strain Pseudomonas aeruginosa PB_1. Minimal inhibitory concentrations (MIC) were determined using the dilution method. The viability of the planktonic cells and biofilm was assessed using the plate count method. Enzymatic profile was determined using the API-ZYM system. Proteins were extracted from the biofilm and planktonic cells and analysed using SDS-PAGE. The MIC of the gemini surfactants was 70 times lower than that of its monomeric analogue. After 4 h of treatment at MIC (0.0145 mM for C6 and 1.013 mM for DTAB), the number of viable planktonic cells was reduce by less than 3 logarithm units. At the concentration ≥MIC, a reduction in the number of viable cells was observed in mature biofilms (p < 0.05). Treatment for 4 h with gemini surfactant at 20 MIC caused complete biofilm eradication. At sub-MIC, the concentration of some enzymes reduced and their protein profiles changed. The results of this study show that due to its superior antibacterial activity, gemini compound C6 can be applied as an effective microbiocide against P. aeruginosa in both planktonic and biofilm forms.}, } @article {pmid29807722, year = {2020}, author = {Yeh, YC and Wang, HY and Lan, CY}, title = {Candida albicans Aro1 affects cell wall integrity, biofilm formation and virulence.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {53}, number = {1}, pages = {115-124}, doi = {10.1016/j.jmii.2018.04.002}, pmid = {29807722}, issn = {1995-9133}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*genetics/growth & development/*pathogenicity ; *Cell Wall ; Fungal Proteins/*genetics ; Gene Knockdown Techniques ; Larva/microbiology ; Lepidoptera/microbiology ; Mutation ; Virulence ; }, abstract = {BACKGROUND: Candida albicans is an opportunistic pathogen capable of causing life-threatening systemic infections. The C. albicans ARO1 gene encodes an arom multifunctional enzyme, which can possibly catalyze reactions of the shikimate pathway to synthesize aromatic amino acids. However, the functions of C. albicans Aro1 have not been extensively characterized.

METHODS: ARO1 knockdown mutant strain was constructed, using a tetracycline-regulated (TR) expression system. Cell growth of the mutant strain was compared with wild type. Effects of the ARO1 gene knockdown on cell wall properties, adhesion to polystyrene and biofilm formation were further investigated. Finally, Galleria mellonella was used as a model host to study the role of ARO1 in virulence of C. albicans.

RESULTS: We showed that defective growth in the ARO1 knockdown strain was rescued by supplemental aromatic amino acids. In addition, the ARO1 knockdown strain was easily aggregated and precipitated. The knockdown of ARO1 also caused changes in cell wall properties and compositions and promoted C. albicans cell adhesion to polystyrene and biofilm formation. Finally, the ARO1 knockdown strain showed attenuation of C. albicans virulence.

CONCLUSION: This work provides new insights into C. albicans metabolism, cell wall and virulence.}, } @article {pmid29807399, year = {2018}, author = {Tao, J and An, FL and Pan, ZH and Lu, YH}, title = {Stimulatory Effects of Sugarcane Molasses on Fumigaclavine C Biosynthesis by Aspergillus fumigatus CY018 via Biofilm Enhancement.}, journal = {Journal of microbiology and biotechnology}, volume = {28}, number = {5}, pages = {748-756}, doi = {10.4014/jmb.1801.01073}, pmid = {29807399}, issn = {1738-8872}, mesh = {*Aspergillus fumigatus/drug effects/metabolism ; Biofilms/*drug effects ; Biomass ; Biotechnology ; *Ergot Alkaloids/analysis/biosynthesis ; *Indole Alkaloids/analysis ; *Molasses ; Saccharum/*chemistry ; }, abstract = {Biofilms are of vital significance in bioconversion and biotechnological processes. In this work, sugarcane molasses was used to enhance biofilms for the improvement of the production of fumigaclavine C (FC), a conidiation-associated ergot alkaloid with strong anti-inflammatory activities. Biofilm formation was more greatly induced by the addition of molasses than the addition of other reported biofilm inducers. With the optimal molasses concentration (400 g/l), the biofilm biomass was 6-fold higher than that with sucrose, and FC and conidia production was increased by 5.8- and 3.1-fold, respectively. Moreover, the global secondary metabolism regulatory gene laeA, FC biosynthetic gene fgaOx3, and asexual central regulatory genes brlA and wetA were upregulated in molasses-based biofilms, suggesting the upregulation of both asexual development and FC biosynthesis. This study provides novel insight into the stimulatory effects of molasses on biofilm formation and supports the widespread application of molasses as an inexpensive raw material and effective inducer for biofilm production.}, } @article {pmid29807235, year = {2018}, author = {Martins, ML and Leite, KLF and Pacheco-Filho, EF and Pereira, AFM and Romanos, MTV and Maia, LC and Fonseca-Gonçalves, A and Padilha, WWN and Cavalcanti, YW}, title = {Efficacy of red propolis hydro-alcoholic extract in controlling Streptococcus mutans biofilm build-up and dental enamel demineralization.}, journal = {Archives of oral biology}, volume = {93}, number = {}, pages = {56-65}, doi = {10.1016/j.archoralbio.2018.05.017}, pmid = {29807235}, issn = {1879-1506}, mesh = {Animals ; Biofilms/*drug effects ; Cattle ; Chromatography, High Pressure Liquid ; Dental Enamel/*drug effects ; Hardness ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Incisor ; Polysaccharides/metabolism ; Propolis/*pharmacology ; Random Allocation ; Streptococcus mutans/*drug effects ; Surface Properties ; Tooth Demineralization/*microbiology ; }, abstract = {OBJECTIVE: The efficacy of a red propolis hydro-alcoholic extract (RP) in controlling Streptococcus mutans biofilm colonization was evaluated. The effect of RP on dental demineralization was also investigated.

METHODS: Chemical composition was determined by High Performance Liquid Chromatography (HPLC). Minimum Inhibitory and Bactericidal Concentration (MIC and MBC, respectively) were investigated against Streptococcus mutans (ATCC 25175). The cytotoxic potential of 3% RP in oral fibroblasts was observed after 1 and 3 min. Bovine dental enamel blocks (N = 24) were used for S. mutans biofilm formation (48 h), simulating 'feast or famine' episodes. Blocks/biofilms were exposed 2×/day, for 3 days, to a cariogenic challenge with sucrose 10% (5 min) and treated (1 min) with: 0.85% saline solution (negative control), 0.12% Chlorhexidine (CHX, positive control for biofilm colonization), 0.05% Sodium Fluoride (NaF, positive control to avoid demineralization) and 3% RP. Biofilms were assessed for viability (CFU/mL), and to observe the concentration of soluble and insoluble extracellular polysaccharides (SEPS and IEPS). Dental demineralization was assessed by the percentage of surface hardness loss (%SHL) and through polarized light microscopy (PLM).

RESULTS: The RP presented 4.0 pH and ºBrix = 4.8. The p-coumaric acid (17.2 μg/mL) and luteolin (15.23 μg/mL) were the largest contents of phenolic acids and flavonoids, respectively. MIC and MBC of RP were 293 μg/mL and 1172 μg/mL, respectively. The 3% RP showed 43% of viably cells after 1 min. Lower number (p < 0.05) of viable bacteria (CFU/mL) was observed after CHX (1.8 × 10[5]) followed by RP (1.8 × 10[7]) treatments. The lowest concentration (μg/CFU) of SEPS (12.6) and IEPS (25.9) was observed in CHX (p < 0.05) followed by RP (17.1 and 54.3), and both differed from the negative control (34.4 and 63.9) (p < 0.05). Considering the %SHL, all groups differed statistically (p < 0.05) from the negative control (46.6%); but NaF (13.9%), CHX (20.1%) and RP (20.7%) did not differ among them (p > 0.05). After all treatments, suggestive areas of caries lesions were observed by PLM, which were lower for CHX and NaF.

CONCLUSION: The 3% RP reduced S. mutans colonization, decreased concentration of extracellular polysaccharides and reduced dental enamel demineralization.}, } @article {pmid29806938, year = {2018}, author = {Yeo, CK and Vikhe, YS and Li, P and Guo, Z and Greenberg, P and Duan, H and Tan, NS and Chan-Park, MB}, title = {Hydrogel Effects Rapid Biofilm Debridement with ex situ Contact-Kill to Eliminate Multidrug Resistant Bacteria in vivo.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {24}, pages = {20356-20367}, doi = {10.1021/acsami.8b06262}, pmid = {29806938}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Debridement ; Drug Resistance, Bacterial ; Drug Resistance, Multiple ; Hydrogels ; Methicillin-Resistant Staphylococcus aureus ; Mice ; Pseudomonas aeruginosa ; Wound Infection ; }, abstract = {Multidrug resistance and the refractory character of bacterial biofilms are among the most difficult challenges in infection treatment. Current antimicrobial strategies typically are much more effective for prevention of biofilm formation than for eradication of established biofilms; these strategies also leave dead bacteria and endotoxin in the infection site, which impairs healing. We report a novel hydrogel that eradicates biofilm bacteria by non-leaching-based debridement followed by ex situ contact-killing (DESCK) away from the infection site. The debridement effect is likely due to the high water swellability and microporosity of the cross-linked network which is made from polyethylene glycol dimethacrylate tethered with a dangling polyethylenimine (PEI) star copolymer. The large pore size of the hydrogel makes the cationic pore walls highly accessible to bacteria. The hydrogel also degrades in the presence of infection cells, releasing star cationic PEI into the infection site to contact-kill bacteria remaining there. DESCK hydrogel effectively kills (>99.9% reduction) biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Pseudomonas aeruginosa (CR-PA) and Acinetobacter baumannii in a murine excisional wound infection model. Silver-based wound dressings (controls) showed almost no killing of CR-PA and MRSA biofilms. This DESCK hydrogel greatly reduces the bioburden and inflammation and promotes wound healing. It has great potential for diverse infection treatment applications.}, } @article {pmid29806505, year = {2018}, author = {Yahav, S and Berkovich, Z and Ostrov, I and Reifen, R and Shemesh, M}, title = {Encapsulation of beneficial probiotic bacteria in extracellular matrix from biofilm-forming Bacillus subtilis.}, journal = {Artificial cells, nanomedicine, and biotechnology}, volume = {46}, number = {sup2}, pages = {974-982}, doi = {10.1080/21691401.2018.1476373}, pmid = {29806505}, issn = {2169-141X}, mesh = {Bacillus subtilis/*cytology/growth & development/*physiology ; *Biofilms ; Capsules ; Coculture Techniques ; Extracellular Matrix/*metabolism ; Gastrointestinal Tract/microbiology ; Hot Temperature ; Humans ; Lactobacillus plantarum/growth & development/*metabolism/physiology ; *Probiotics ; Survival Analysis ; }, abstract = {Probiotics, live microbial supplements, are often incorporated into foods and beverages to provide putative health benefits. To ensure their beneficial effects, these organisms must survive processing and storage of food, its passage through the upper gastrointestinal tract (GIT), and subsequent chemical ingestion processes until they reach their target organ. However, there is considerable loss of viability of probiotic bacteria in the acidic conditions of the stomach and the high bile concentration in the small intestine. Bacillus subtilis, a spore-forming non-pathogenic bacterium, recently has gained interest in its probiotic properties; it can effectively maintain a favorable balance of microflora in the GIT. In addition, B. subtilis produces an extracellular matrix that protects it from stressful environments. We suggested that the extracellular matrix produced by B. subtilis could protect other probiotic bacteria and therefore potentially could be used as a vehicle for delivering viable probiotic cells to humans. Therefore, we developed a novel cultivation system that enables co-culturing of B. subtilis along with probiotic lactic acid bacteria (LAB) by increasing production of the extracellular matrix by B. subtilis cells. Moreover, we showed that B. subtilis improved survivability of LAB during food preparation, storage and ingestion. Therefore, we believe that the results of our study will provide a novel technique of using a natural system for preservation and delivery of probiotics to humans.}, } @article {pmid29806143, year = {2018}, author = {Adnan, NNM and Sadrearhami, Z and Bagheri, A and Nguyen, TK and Wong, EHH and Ho, KKK and Lim, M and Kumar, N and Boyer, C}, title = {Exploiting the Versatility of Polydopamine-Coated Nanoparticles to Deliver Nitric Oxide and Combat Bacterial Biofilm.}, journal = {Macromolecular rapid communications}, volume = {39}, number = {13}, pages = {e1800159}, doi = {10.1002/marc.201800159}, pmid = {29806143}, issn = {1521-3927}, mesh = {Biofilms/*drug effects/growth & development ; *Coated Materials, Biocompatible/chemistry/pharmacology ; *Drug Carriers/chemistry/pharmacology ; Indoles/*chemistry ; Nanoparticles/*chemistry ; *Nitric Oxide/chemistry/pharmacology ; Polymers/*chemistry ; Pseudomonas aeruginosa/*physiology ; }, abstract = {In this study, an antimicrobial platform in the form of nitric oxide (NO) gas-releasing polydopamine (PDA)-coated iron oxide nanoparticles (IONPs) is developed for combating bacterial biofilms. NO is bound to the PDA-coated IONPs via the reaction between NO and the secondary amine moieties on PDA to form N-diazeniumdiolate (NONOate) functionality. To impart colloidal stability to the nanoparticles in aqueous solutions (e.g., phosphate buffered saline (PBS) and bacteria cell culture media M9), a polymer bearing hydrophilic and amine pendant groups, P(OEGMA)-b-P(ABA), is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization and is subsequently grafted onto the PDA-coated IONPs by employing the Schiff base/Michael addition reaction between o-quinone and a primary amine. These nanoparticles are able to effectively disperse Pseudomonas aeruginosa biofilms (up to 79% dispersal) at submicromolar NO concentrations. In addition, the nanoparticles demonstrate excellent bactericidal activity toward P. aeruginosa planktonic and biofilm cells (up to 5-log10 reduction).}, } @article {pmid29805025, year = {2018}, author = {Garcia, LGS and Guedes, GMM and da Silva, MLQ and Castelo-Branco, DSCM and Sidrim, JJC and Cordeiro, RA and Rocha, MFG and Vieira, RS and Brilhante, RSN}, title = {Effect of the molecular weight of chitosan on its antifungal activity against Candida spp. in planktonic cells and biofilm.}, journal = {Carbohydrate polymers}, volume = {195}, number = {}, pages = {662-669}, doi = {10.1016/j.carbpol.2018.04.091}, pmid = {29805025}, issn = {1879-1344}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Chitosan/chemistry/*pharmacology ; Molecular Weight ; Plankton/*drug effects ; }, abstract = {Difficulties in the treatment of Candida spp. invasive infections are usually related to the formation of biofilms. The aim of this study was to determine the effects of molecular weight (MW) of chitosan (using high (HMW), medium (MMW) and low (LMW) molecular weight chitosan) on Candida albicans, Candida tropicalis and Candida parapsilosis sensu stricto. The deacetylation degree (DD) and molecular weight M were measured by potentiometric titration and viscosimetry, respectively. The planktonic shape activity was quantified by broth microdilution, and the activity against biofilm was quantified by metabolic activity through XTT 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]- 2H-tetrazolium hydroxide and biomass formation (crystal violet). The influence of chitosan MW on the planktonic form of Candida spp. was strain dependent. Fungal growth decreased with increasing chitosan MW for C. tropicalis and C. parapsilosis, while chitosan MW did not modulate the effect for C. albicans. With regard to the formation of biofilms, in both the adhesion and mature phases, the biomass and metabolic activities of Candida spp. were reduced by about 70% and 80%, respectively for each phase.}, } @article {pmid29803031, year = {2018}, author = {Çelik, A and Casey, E and Hasar, H}, title = {Degradation of oxytetracycline under autotrophic nitrifying conditions in a membrane aerated biofilm reactor and community fingerprinting.}, journal = {Journal of hazardous materials}, volume = {356}, number = {}, pages = {26-33}, doi = {10.1016/j.jhazmat.2018.05.040}, pmid = {29803031}, issn = {1873-3336}, mesh = {Ammonium Compounds/metabolism ; Anti-Bacterial Agents/*metabolism ; Bacteria/classification/genetics/metabolism ; Biofilms ; Bioreactors/microbiology ; Membranes, Artificial ; Nitrification ; Oxidation-Reduction ; Oxytetracycline/*metabolism ; RNA, Ribosomal, 16S/genetics ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Pharmaceuticals in waterbodies are a growing concern due to their extensive uses and adverse effects on aquatic life. Oxytetracycline (OTC) is one of tetracycline antibiotic group used for treatment of animals and humans. This study evaluates the simultaneous oxidation of OTC and ammonium under autotrophic nitrifying conditions by using a membrane aerated biofilm reactor (MABR) as it provides an appropriate environment for the antibiotic-degrading bacteria. The results showed that MABR achieved fluxes of 1.62 mg OTC/m[2].d and 1117 mg N/m[2].d while the fluxes of O2 (JOTC-O2) utilized for OTC and NH4-N (JNH4-N-O2) oxidation were calculated to be 2.94 and 5105 mg O2/m[2].d, respectively. Three transformation products, 4-Epi-OTC, α-Apo-OTC and β-Apo-OTC, were identified and measured at ppb levels. The biofilm community comprised of Bacteria environmental samples, b-proteobacteria, CFB group bacteria, g-proteobacteria, d-proteobacteria and a-proteobacteria.}, } @article {pmid29797436, year = {2018}, author = {Ramiro, FS and de Lira, E and Soares, G and Retamal-Valdes, B and Feres, M and Figueiredo, LC and Faveri, M}, title = {Effects of different periodontal treatments in changing the prevalence and levels of Archaea present in the subgingival biofilm of subjects with periodontitis: A secondary analysis from a randomized controlled clinical trial.}, journal = {International journal of dental hygiene}, volume = {16}, number = {4}, pages = {569-575}, doi = {10.1111/idh.12347}, pmid = {29797436}, issn = {1601-5037}, support = {2013/10139-6//São Paulo Research Foundation (FAPESP, Brazil)/ ; 2012/23503-5//São Paulo Research Foundation (FAPESP, Brazil)/ ; }, mesh = {Adult ; Amoxicillin/*administration & dosage ; Archaea/*isolation & purification ; *Biofilms ; Chronic Periodontitis/*microbiology/*therapy ; Combined Modality Therapy ; Dental Plaque/*microbiology ; *Dental Scaling ; Drug Therapy, Combination ; Female ; Gingiva/*microbiology ; Humans ; Male ; Metronidazole/*administration & dosage ; Middle Aged ; *Root Planing ; Time Factors ; Treatment Outcome ; }, abstract = {OBJECTIVE: The aim of this randomized double-blind and placebo-controlled study was to assess if periodontal treatment with or without systemic antibiotic would change the mean level of Archaea.

METHODS: Fifty-nine (59) subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with metronidazole (MTZ; 400 mg/TID) or either with MTZ and amoxicillin (AMX; 500 mg/TID) for 14 days. Clinical and microbiological examinations were performed at baseline and at 6 months post-SRP. Six subgingival plaque samples per subject were analysed for the presence and levels of Archaea using quantitative polymerase chain reaction.

RESULTS: Scaling and root planing alone or combined with MTZ or MTZ + AMX significantly reduced the prevalence of subjects colonized by Archaea at 6 months post-therapy, without significant differences among groups (P > .05). Both therapies led to a statistically significant decrease in the mean percentage of sites colonized by Archaea (P < .05). The MTZ and MTZ + AMX group had a significantly lower mean number of sites colonized by Archaea and lower levels of these micro-organisms at sites with probing depth ≥5 mm at 6 months compared with SRP group (P < .05).

CONCLUSION: Periodontal treatments including adjunctive MTZ or MTZ + AMX are more effective than mechanical treatment alone in reducing the levels and prevalence of sites colonized by Archaea in subjects with chronic periodontitis.}, } @article {pmid29796560, year = {2018}, author = {Tessier, J and Golmohamadi, M and Wilkinson, KJ and Schmitzer, AR}, title = {Anti-staphylococcal biofilm activity of miconazoctylium bromide.}, journal = {Organic & biomolecular chemistry}, volume = {16}, number = {23}, pages = {4288-4294}, doi = {10.1039/c8ob00897c}, pmid = {29796560}, issn = {1477-0539}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology/toxicity ; Biofilms/*drug effects ; Hemolysis/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Miconazole/*analogs & derivatives/chemical synthesis/*pharmacology/toxicity ; Microbial Sensitivity Tests ; }, abstract = {We designed and synthesized miconazole analogues containing a substituted imidazolium moiety. The structural modification of the miconazole led to a compound with high potency to prevent the formation and disrupt bacterial biofilms, as a result of accumulation in the biofilm matrix, permeabilization of the bacterial membrane and generation of reactive oxygen species in the cytoplasm.}, } @article {pmid29796224, year = {2018}, author = {Bimanand, L and Taherikalani, M and Jalilian, FA and Sadeghifard, N and Ghafourian, S and Mahdavi, Z and Mohamadi, S and Sayehmiri, K and Hematian, A and Pakzad, I}, title = {Association between biofilm production, adhesion genes and drugs resistance in different SCCmec types of methicillin resistant Staphylococcus aureus strains isolated from several major hospitals of Iran.}, journal = {Iranian journal of basic medical sciences}, volume = {21}, number = {4}, pages = {400-403}, pmid = {29796224}, issn = {2008-3866}, abstract = {OBJECTIVES: The ability of bacteria to produce biofilm and adhesion makes them more resistant to antibiotics. The current study aims to evaluate the biofilm formation by Staphylococcus aureus and to determine the prevalence of adhesion genes, also their correlation with drug resistance.

MATERIALS AND METHODS: A total of 96 MRSA were collected from hospitals of Iran's western provinces during 2012 to 2013. The presence of ica A, B, C, D, clfA, cna, fnbA, mecA genes were determined by PCR technique. Biofilm formation was studied by microtiter plate assay, the clonal relations of the strains were examined by SCCmec and Spa typing.

RESULTS: The results demonstrated that 96 % of isolates were biofilm producers. The distributions of biofilm formation between isolates were 4.2%, 54.2%, 35.4% as high, moderate and weak, respectivelly. The highest biofilm production was observed from blood culture isolates. All virulent genes icaA,B, C, D, clfA, cna, fnbA were observed in moderate and weak biofilm formation isolates. Among high biofilm formation isolates, icaB and cna genes were not seen. Statistical analysis showed that there was a significant correlation between ica, fnbA and the biofilm production, but there was not a significant correlation between the type of samples and drug resistance, spa type and SCCmec type with biofilm production (P>0.05). Frequency of All virulent genes in type III SCCmec was higher than other types.

CONCLUSION: The majority of MRSA isolates were biofilm producers and blood isolates ranked as the great biofilm producer. In these isolates ica D and fnbA genes are correlated with biofilm production.}, } @article {pmid29795121, year = {2018}, author = {Mandakhalikar, KD and Rahmat, JN and Chiong, E and Neoh, KG and Shen, L and Tambyah, PA}, title = {Extraction and quantification of biofilm bacteria: Method optimized for urinary catheters.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {8069}, pmid = {29795121}, issn = {2045-2322}, mesh = {Animals ; Biofilms/*growth & development ; Catheter-Related Infections/*microbiology ; Catheters, Indwelling/*microbiology ; Escherichia coli/classification/isolation & purification/ultrastructure ; Escherichia coli Infections/*microbiology ; Female ; Humans ; Mice ; Microscopy, Electron, Scanning/*methods ; Swine ; Urinary Catheterization/methods ; Urinary Catheters/*microbiology ; Urinary Tract Infections/*microbiology ; }, abstract = {Bacterial biofilms are responsible for the failure of many medical devices such as urinary catheters and are associated with many infectious and non-infectious complications. Preclinical and clinical evaluation of novel catheter coatings to prevent these infections needs to accurately quantify the bacterial load in the biofilm in vitro and ex vivo. There is currently no uniform gold standard for biofilm quantification for different surfaces and established biofilms. We have tried to establish a simple, accurate and reproducible method for extraction and measurement of biofilm bacteria on indwelling catheters, using a combination of vortexing and sonication. We demonstrate the usefulness of this method for catheters of different sizes - 3 Fr to 14 Fr - in vitro, in murine and porcine models, and indwelling in human clinical subjects. We also demonstrate consistent results with complex and polymicrobial biofilms. We believe that this standardized reproducible method will assist the assessment of biofilms in general and urological devices in particular in efforts to harness novel technologies to prevent healthcare associated infections.}, } @article {pmid29795120, year = {2018}, author = {Brahma, U and Kothari, R and Sharma, P and Bhandari, V}, title = {Antimicrobial and anti-biofilm activity of hexadentated macrocyclic complex of copper (II) derived from thiosemicarbazide against Staphylococcus aureus.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {8050}, pmid = {29795120}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Membrane Permeability ; Cell Proliferation ; Cells, Cultured ; Copper/*pharmacology ; Humans ; Macrophages/cytology/drug effects/metabolism ; Mice ; Microbial Sensitivity Tests ; Organometallic Compounds/*pharmacology ; Semicarbazides/*chemistry ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects ; }, abstract = {Multidrug-resistant pathogens causing nosocomial and community acquired infections delineate a significant threat to public health. It had urged to identify new antimicrobials and thus, generated interest in studying macrocyclic metal complex, which has been studied in the past for their antimicrobial activity. Hence, in the present study, we have evaluated the antimicrobial activity of the hexadentated macrocyclic complex of copper (II) (Cu Complex) derived from thiosemicarbazide against Gram-positive and Gram-negative bacteria. We observed increased susceptibility against standard isolates of Staphylococcus aureus with a minimum inhibitory concentration (MIC) range of 6.25 to 12.5 μg/mL. Similar activity was also observed towards methicillin resistant and sensitive clinical isolates of S. aureus from human (n = 20) and animal (n = 20) infections. The compound has rapid bactericidal activity, and we did not observe any resistant mutant of S. aureus. The compound also exhibited antibiofilm activity and was able to disrupt pre-formed biofilms. Cu complex showed increased susceptibility towards intracellular S. aureus and was able to reduce more than 95% of the bacterial load at 10 μg/mL. Overall, our results suggest that Cu complex with its potent anti-microbial and anti-biofilm activity can be used to treat MRSA infections and evaluated further clinically.}, } @article {pmid29794993, year = {2018}, author = {Soares, A and Gomes, LC and Mergulhão, FJ}, title = {Comparing the Recombinant Protein Production Potential of Planktonic and Biofilm Cells.}, journal = {Microorganisms}, volume = {6}, number = {2}, pages = {}, pmid = {29794993}, issn = {2076-2607}, abstract = {Recombinant protein production in bacterial cells is commonly performed using planktonic cultures. However, the natural state for many bacteria is living in communities attached to surfaces forming biofilms. In this work, a flow cell system was used to compare the production of a model recombinant protein (enhanced green fluorescent protein, eGFP) between planktonic and biofilm cells. The fluorometric analysis revealed that when the system was in steady state, the average specific eGFP production from Escherichia coli biofilm cells was 10-fold higher than in planktonic cells. Additionally, epifluorescence microscopy was used to determine the percentage of eGFP-expressing cells in both planktonic and biofilm populations. In steady state, the percentage of planktonic-expressing cells oscillated around 5%, whereas for biofilms eGFP-expressing cells represented on average 21% of the total cell population. Therefore, the combination of fluorometric and microscopy data allowed us to conclude that E. coli biofilm cells can have a higher recombinant protein production capacity when compared to their planktonic counterparts.}, } @article {pmid29793410, year = {2019}, author = {Borkar, MR and Nandan, S and Nagaraj, HKM and Puttur, J and Manniyodath, J and Chatterji, D and Coutinho, EC}, title = {4-Hydroxy-2-pyridone Derivatives and the δ-pyrone Isostere as Novel Agents Against Mycobacterium smegmatis Biofilm Inhibitors.}, journal = {Medicinal chemistry (Shariqah (United Arab Emirates))}, volume = {15}, number = {1}, pages = {28-37}, doi = {10.2174/1573406414666180525075755}, pmid = {29793410}, issn = {1875-6638}, mesh = {Anti-Bacterial Agents/chemical synthesis/pharmacokinetics/*pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Mycobacterium smegmatis/*drug effects ; Pyridones/chemical synthesis/pharmacokinetics/*pharmacology ; Pyrones/chemical synthesis/pharmacokinetics/*pharmacology ; }, abstract = {BACKGROUND: The treatment of a bacterial infection when the bacterium is growing in a biofilm is a vexed issue. This is because the bacteria in a biofilm behaves differently compared to the individual planktonic free-form. As a result, traditional antibacterial agents lose their activity.

OBJECTIVE: Presently, there are not many drugs that are effective against bacteria growing in biofilms. Based on literature reports, we have sought to develop novel derivatives of 4-hydroxy-2- pyridone as both antimycobacterial and antibiofilm agents.

METHODS: The pyridone derivatives were synthesized by reacting 4-hydroxy-6-methyl-2H-pyran-2- one with appropriate amines and followed by reaction with substituted phenyl isocyanates as reported in the literature.

RESULTS: Four compounds in this series significantly inhibit the growth and formation of biofilm by Mycobacterium smegmatis (mc2 155 strain) at 50 µg/ml. Further, in silico evaluation of the ADME parameters shows that these compounds possess good drug-like properties and have the potential to be developed both as antibiofilm and as oral antimycobacterial agents.

CONCLUSION: This finding is of significance as presently very few small molecules are known to inhibit biofilm formation in mycobacteria. These compounds are unique in the sense that they are more potent against Mycobacterium smegmatis in the biofilm state compared to the planktonic form.}, } @article {pmid29792779, year = {2018}, author = {Ferreira, ML and Araújo, BF and Gonçalves, IR and Royer, S and Campos, PA and Machado, LG and Batistão, DWF and Brito, CS and Gontijo-Filho, PP and Ribas, RM}, title = {Association of Colistin-Resistant KPC Clonal Strains with Subsequent Infections and Colonization and Biofilm Production.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {24}, number = {10}, pages = {1441-1449}, doi = {10.1089/mdr.2018.0043}, pmid = {29792779}, issn = {1931-8448}, mesh = {Adult ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion ; Bacterial Proteins/biosynthesis/*genetics ; Biofilms ; Brazil ; Colistin/*pharmacology ; Colony Count, Microbial ; Cross Infection/microbiology ; Drug Resistance, Bacterial/*drug effects ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Klebsiella Infections/*microbiology/mortality ; Klebsiella pneumoniae/*genetics ; Microbial Sensitivity Tests ; beta-Lactamases/biosynthesis/*genetics ; }, abstract = {Carbapenemase-producing organisms are pandemic and a significant threat to public health. We investigated the clonal relatedness of colistin-resistant Klebsiella pneumoniae strains producing KPC-type carbapenemase (KPC-KP) causing subsequent infections or colonization. Moreover, we aimed to gain insight into the ability of biofilm production in K. pneumoniae strains producing carbapenemase. Twenty-two consecutive KPC-KP and one KPC-negative strain was identified from an adult intensive care unit in Brazil. Seventy-five percent of isolates that harbored the blaKPC gene exhibited genetic relatedness by pulsed-field gel electrophoresis, and none presented the plasmid-mediated mcr-1 and blaNDM genes. This study showed that the majority of repeated KPC infections in adults were caused by a clone that caused the previous infections/colonizations even after a long period of time and illustrates the capacity of multiple clones producing biofilms to coexist in the same patient at the same time, becoming a reservoir of KPC-KP in the hospital environment.}, } @article {pmid29791881, year = {2018}, author = {Cai, C and Hu, S and Chen, X and Ni, BJ and Pu, J and Yuan, Z}, title = {Effect of methane partial pressure on the performance of a membrane biofilm reactor coupling methane-dependent denitrification and anammox.}, journal = {The Science of the total environment}, volume = {639}, number = {}, pages = {278-285}, doi = {10.1016/j.scitotenv.2018.05.164}, pmid = {29791881}, issn = {1879-1026}, mesh = {Anaerobiosis ; *Biofilms ; *Bioreactors ; Denitrification ; Methane/*metabolism ; Nitrogen ; Oxidation-Reduction ; Partial Pressure ; Waste Disposal, Fluid/methods ; }, abstract = {Complete nitrogen removal has recently been demonstrated by integrating anaerobic ammonium oxidation (anammox) and denitrifying anaerobic methane oxidation (DAMO) processes. In this work, the effect of methane partial pressure on the performance of a membrane biofilm reactor (MBfR) consisting of DAMO and anammox microorganisms was evaluated. The activities of DAMO archaea and DAMO bacteria in the biofilm increased significantly with increased methane partial pressure, from 367 ± 9 and 58 ± 22 mg-N L[-1]d[-1] to 580 ± 12 and 222 ± 22 mg-N L[-1]d[-1], respectively, while the activity of anammox bacteria only increased slightly, when the methane partial pressure was elevated from 0.24 to 1.39 atm in the short-term batch tests. The results were supported by a long-term (seven weeks) continuous test, when the methane partial pressure was dropped from 1.39 to 0.78 atm. The methane utilization efficiency was always above 96% during both short-term and long-term tests. Taken together, nitrogen removal rate (especially the nitrate reduction rate by DAMO archaea) and methane utilization efficiency could be maintained at high levels in a broad range of methane partial pressure (0.24-1.39 atm in this study). In addition, a previously established DAMO/anammox biofilm model was used to analyze the experimental data. The observed impacts of methane partial pressure on biofilm activity were well explained by the modeling results. These results suggest that methane partial pressure can potentially be used as a manipulated variable to control reaction rates, ultimately to maintain high nitrogen removal efficiency, according to nitrogen loading rate.}, } @article {pmid29790590, year = {2018}, author = {Arruda, CNF and Salles, MM and Badaró, MM and Sorgini, DB and Oliveira, VC and Macedo, AP and Silva-Lovato, CH and Paranhos, HFO}, title = {Evaluation of biofilm removal and adverse effects on acrylic resin by diluted concentrations of sodium hypochlorite and Ricinus communis solutions.}, journal = {Gerodontology}, volume = {}, number = {}, pages = {}, doi = {10.1111/ger.12348}, pmid = {29790590}, issn = {1741-2358}, abstract = {PURPOSE: To verify whether 0.1% and 0.2% sodium hypochlorite (NaOCl), and 8% Ricinus communis (RC) were able to remove denture biofilm without causing deleterious effects to acrylic resin.

BACKGROUND: Previous data show that denture cleansers are effective in reducing biofilm; however, they can change acrylic resin properties.

METHODS: In a crossover trial, 47 denture wearers brushed and soaked their dentures (20 min/14 d): control, 0.85% saline; SH1, 0.1% NaOCl; SH2, 0.2% NaOCl and RC. Denture biofilm on the intaglio surface was stained, photographed and quantified (Image Tool[®]). Furthermore, 80 rectangular and 80 disc-shaped specimens (Lucitone 550) were assigned into tested solutions (n = 20), simulating 5 years of daily short immersions (20 minutes). A colorimeter and the National Bureau of Standards units (NBS) determined colour data (ΔE). Surface roughness and flexural strength were measured using rugosimeter and universal testing machine, respectively. Data were compared by the Friedman test (α = .05) followed by Wilcoxon, corrected by Bonferroni (α = .005) (clinical) and Kruskal-Wallis followed by the Dunn test (α = .05) (laboratorial).

RESULTS: SH2 (MR=1.77) showed lower biofilm coverage; SH1 (MR = 2.37) and RC (MR = 2.74) presented intermediated values. RC (1.10 [0.96:1.75]) revealed higher colour alteration than SH1 (0.71 [0.62:0.80]) and SH2 (0.74 [0.58:0.85]); however, NBS classified all solutions as "trace" (0.0-0.5). There was no statistical significance for surface roughness (P = .760) and flexural strength (P = .547).

CONCLUSIONS: The 0.2% NaOCl showed the best clinical performance and did not cause adverse effects on acrylic resin on laboratory analyses.}, } @article {pmid29790304, year = {2018}, author = {Mi, G and Shi, D and Wang, M and Webster, TJ}, title = {Reducing Bacterial Infections and Biofilm Formation Using Nanoparticles and Nanostructured Antibacterial Surfaces.}, journal = {Advanced healthcare materials}, volume = {7}, number = {13}, pages = {e1800103}, doi = {10.1002/adhm.201800103}, pmid = {29790304}, issn = {2192-2659}, mesh = {Anti-Bacterial Agents/administration & dosage/*chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Infections/drug therapy/*prevention & control ; Biofilms ; Biomimetics ; Drug Carriers/administration & dosage/chemistry/pharmacology ; Drug Delivery Systems/*methods ; Drug Resistance, Bacterial ; Humans ; Lipids/chemistry ; Metals/chemistry/pharmacology ; Nanostructures/*chemistry ; Surface Properties ; }, abstract = {With the rapid spreading of resistance among common bacterial pathogens, bacterial infections, especially antibiotic-resistant bacterial infections, have drawn much attention worldwide. In light of this, nanoparticles, including metal and metal oxide nanoparticles, liposomes, polymersomes, and solid lipid nanoparticles, have been increasingly exploited as both efficient antimicrobials themselves or as delivery platforms to enhance the effectiveness of existing antibiotics. In addition to the emergence of widespread antibiotic resistance, of equal concern are implantable device-associated infections, which result from bacterial adhesion and subsequent biofilm formation at the site of implantation. The ineffectiveness of conventional antibiotics against these biofilms often leads to revision surgery, which is both debilitating to the patient and expensive. Toward this end, micro- and nanotopographies, especially those that resemble natural surfaces, and nonfouling chemistries represent a promising combination for long-term antibacterial activity. Collectively, the use of nanoparticles and nanostructured surfaces to combat bacterial growth and infections is a promising solution to the growing problem of antibiotic resistance and biofilm-related device infections.}, } @article {pmid29788897, year = {2018}, author = {Zangirolami, AC and Inada, NM and Bagnato, VS and Blanco, KC}, title = {Biofilm Destruction on Endotracheal Tubes by Photodynamic Inactivation.}, journal = {Infectious disorders drug targets}, volume = {18}, number = {3}, pages = {218-223}, doi = {10.2174/1871526518666180523085754}, pmid = {29788897}, issn = {2212-3989}, mesh = {Anti-Infective Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Curcumin/pharmacology ; *Equipment Contamination ; *Intubation, Intratracheal ; Light ; Microbial Viability/*drug effects ; Photosensitizing Agents/pharmacology ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/*drug effects/growth & development ; }, abstract = {BACKGROUND: Hospital infections are a public health problem that can occur with the use of catheters and endotracheal tubes (ETT). Pathogenic microorganisms may adhere to surfaces of these materials forming a biofilm and produce an extracellular polymer matrix that promotes resistance of microorganisms to factors such as pH, temperature and drugs. The conventional treatment is being made by antibiotics, which has serious adverse effects in immunocompromised patients. Photodynamic therapy (PDT) is an alternative for microbial inactivation noninvasive without the stimulus of microbial resistance. PDT combines light and a photosensitive molecule for produce reactive oxygen species leading to bacterial death.

OBJECTIVE: The objective of this study was to determine the efficacy of a PDT protocol in bacterial inactivation of biofilm ETT.

METHOD: The photosensitizer (PS) used was curcumin and the light source LED at 450nm. A statistical experimental design was used for optimization of antimicrobial PDT.

RESULTS: The highest microbial inactivation was observed with 70% biofilm reduction in conditions 1.25 mg/mL curcumin, 2 h of PS incubation and 50 J/cm2.

CONCLUSION: This study described the photodynamic death of bacteria forming a biofilm on ETT. Parameters optimization was important for clinical application of this system.}, } @article {pmid29788432, year = {2018}, author = {Cai, JN and Jung, JE and Lee, MH and Choi, HM and Jeon, JG}, title = {Sucrose challenges to Streptococcus mutans biofilms and the curve fitting for the biofilm changes.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {7}, pages = {}, doi = {10.1093/femsec/fiy091}, pmid = {29788432}, issn = {1574-6941}, mesh = {Acids/metabolism ; Biofilms/*growth & development ; Dental Caries/microbiology/*pathology ; Humans ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/*biosynthesis ; Streptococcus mutans/*metabolism ; Sucrose/*metabolism ; }, abstract = {The relationship between sugar level and development of dental caries has long been a main topic in dentistry. However, as a ubiquitous component of the modern diet, sucrose is mainly derived from three meals a day, rather than a long time exposure. In this study, various concentrations of sucrose were provided to Streptococcus mutans biofilms for 1 h per exposure (three times per day) to imitate a human meal pattern. And then the relationship between sucrose concentration and changes in the treated biofilms was determined. The results indicated that the components and acid production of the treated biofilms changed in a second-order polynomial curve pattern with sucrose concentration increase, which were confirmed by CLSM and SEM analyses. However, gene expression related to extracellular polysaccharides (EPS) formation, acid production and tolerance was up-regulated with sucrose concentration increase, which might have been due to compensation for the decrease in EPS formation and acid production by the biofilms at higher concentrations of sucrose. These findings suggest that sucrose in the range of 1%-5% can support the highest acid production and accumulation of S. mutans biofilms, which may further increase its cariogenic potential. However, additional studies are required to confirm the relationships in human cariogenic biofilms.}, } @article {pmid29788056, year = {2018}, author = {Miquel Guennoc, C and Rose, C and Labbé, J and Deveau, A}, title = {Bacterial biofilm formation on the hyphae of ectomycorrhizal fungi: a widespread ability under controls?.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {7}, pages = {}, doi = {10.1093/femsec/fiy093}, pmid = {29788056}, issn = {1574-6941}, mesh = {Ascomycota/metabolism ; Biofilms/*growth & development ; Hyphae/*metabolism ; Laccaria/*metabolism ; Microbial Interactions/*physiology ; Mycorrhizae ; Plant Roots/microbiology ; Pseudomonas fluorescens/genetics/*growth & development ; Soil ; Soil Microbiology ; Symbiosis ; Trees ; }, abstract = {Ectomycorrhizal (ECM) fungi establish symbiosis with roots of most trees of boreal and temperate ecosystems and are major drivers of nutrient fluxes between trees and the soil. ECM fungi constantly interact with bacteria all along their life cycle and the extended networks of hyphae provide a habitat for complex bacterial communities. Despite the important effects these bacteria can have on the growth and activities of ECM fungi, little is known about the mechanisms by which these microorganisms interact. Here we investigated the ability of bacteria to form biofilm on the hyphae of the ECM fungus Laccaria bicolor. We showed that the ability to form biofilms on the hyphae of the ECM fungus is widely shared among soil bacteria. Conversely, some fungi, belonging to the Ascomycete class, did not allow for the formation of bacterial biofilms on their surfaces. The formation of biofilms was also modulated by the presence of tree roots and ectomycorrhizae, suggesting that biofilm formation does not occur randomly in soil but that it is regulated by several biotic factors. In addition, our study demonstrated that the formation of bacterial biofilm on fungal hyphae relies on the production of networks of filaments made of extracellular DNA.}, } @article {pmid29787932, year = {2018}, author = {Johansen, MP and Prentice, E and Cresswell, T and Howell, N}, title = {Initial data on adsorption of Cs and Sr to the surfaces of microplastics with biofilm.}, journal = {Journal of environmental radioactivity}, volume = {190-191}, number = {}, pages = {130-133}, doi = {10.1016/j.jenvrad.2018.05.001}, pmid = {29787932}, issn = {1879-1700}, mesh = {Adsorption ; Biofilms ; Cesium/analysis/*chemistry ; Environmental Monitoring ; Models, Chemical ; Plastics/*chemistry ; Strontium/analysis/*chemistry ; Water Pollutants, Chemical/analysis/*chemistry ; }, abstract = {The adsorption of radiocesium and radiostrontium onto a range of natural materials has been well quantified, but not for the new media of environmental plastics, which may have enhanced adsorption due to surface-weathering and development of biofilms. Microplastic samples were deployed in freshwater, estuarine and marine conditions, then characterised using infrared spectroscopy to document changes to the plastic surface (vs interior). Synchrotron elemental mapping data revealed surfaces that were well-covered by accumulation of reactive water solutes and sulphur, but, in contrast, had highly discrete coverage of elements such as Fe and Ti, indicating adhered mineral/clay-associated agglomerates that may increase overall adsorption capacity. Plastics that had been deployed for nearly five months adsorbed radionuclides in both freshwater and estuarine conditions with the highest Kd for cesium (Cs) in freshwater (80 ml g[-1]) and lowest for strontium (Sr) in estuarine conditions (5 ml g[-1]). The degree of Cs and Sr adsorption onto plastics appears to be approximately 2-3 orders of magnitude lower than for sediment reference values. While lower than for sediments, adsorption occurred on all samples and may indicate a significant radionuclide reservoir, given that plastics are relatively buoyant and mobile in water regimes, and are increasing in global aquatic systems.}, } @article {pmid29785845, year = {2018}, author = {Lai, CY and Lv, PL and Dong, QY and Yeo, SL and Rittmann, BE and Zhao, HP}, title = {Bromate and Nitrate Bioreduction Coupled with Poly-β-hydroxybutyrate Production in a Methane-Based Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {52}, number = {12}, pages = {7024-7031}, doi = {10.1021/acs.est.8b00152}, pmid = {29785845}, issn = {1520-5851}, mesh = {Biofilms ; *Bioreactors ; *Bromates ; Hydroxybutyrates ; Methane ; Nitrates ; Polyesters ; }, abstract = {This work demonstrates bromate (BrO3[-]) reduction in a methane (CH4)-based membrane biofilm reactor (MBfR), and it documents contrasting impacts of nitrate (NO3[-]) on BrO3[-] reduction, as well as formation of poly-β-hydroxybutyrate (PHB), an internal C- and electron-storage material. When the electron donor, CH4, was in ample supply, NO3[-] enhanced BrO3[-] reduction by stimulating the growth of denitrifying bacteria (Meiothermus, Comamonadaceae, and Anaerolineaceae) able to reduce BrO3[-] and NO3[-] simultaneously. This was supported by increases in denitrifying enzymes (e.g., nitrate reductase, nitrite reductase, nitrous-oxide reductase, and nitric-oxide reductase) through quantitative polymerase chain reaction (qPCR) analysis and metagenomic prediction of these functional genes. When the electron donor was in limited supply, NO3[-] was the preferred electron acceptor over BrO3[-] due to competition for the common electron donor; this was supported by the significant oxidation of stored PHB when NO3[-] was high enough to cause electron-donor limitation. Methanotrophs (e.g., Methylocystis, Methylomonas, and genera within Comamonadaceae) were implicated as the main PHB producers in the biofilms, and their ability to oxidize PHB mitigated the impacts of competition for CH4.}, } @article {pmid29785633, year = {2018}, author = {Guo, M and Fang, Z and Sun, L and Sun, D and Wang, Y and Li, C and Wang, R and Liu, Y and Hu, H and Liu, Y and Xu, D and Gooneratne, R}, title = {Regulation of Thermostable Direct Hemolysin and Biofilm Formation of Vibrio parahaemolyticus by Quorum-Sensing Genes luxM and luxS.}, journal = {Current microbiology}, volume = {75}, number = {9}, pages = {1190-1197}, pmid = {29785633}, issn = {1432-0991}, support = {31371746//Natural Science Foundation of China/ ; GDOU2013050205//higher educational cultivation program for major scientific research projects of Guangdong Ocean University/ ; 2014050203//higher educational cultivation program for major scientific research projects of Guangdong Ocean University/ ; 2015ZZ02//the scientific research program of administration of quality and technology supervision of Guangdong province/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Bacterial Toxins/genetics/metabolism ; Biofilms/*growth & development ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial/*genetics ; Hemolysin Proteins/*genetics/metabolism ; Quorum Sensing/*genetics ; Transcription, Genetic ; Vibrio parahaemolyticus/*genetics/growth & development/metabolism ; Virulence/genetics ; }, abstract = {Vibrio parahaemolyticus is a seafood opportunistic pathogen. There are evidences suggesting that virulence skills, including hemolytic activity and biofilm formation, are regulated by the luxM/luxS-dependent quorum-sensing system in V. parahaemolyticus, and their regulatory mechanism is not well understood. To better understand the virulence regulatory mechanism of V. parahaemolyticus, the luxM deletion (△luxM) and luxS deletion (△luxS) mutants were constructed and their impacts on growth, hemolysin activity, and biofilm were investigated. Results show that both luxM and luxS are involved in the adaptation to environmental conditions in early adaptive-log phase growth of V. parahaemolyticus. Thermostable direct hemolysin gene (tdh) was negatively regulated by luxM and positively regulated by luxS. The biofilm formation was negatively regulated by both luxS and luxM. This study provides an insight into some aspects of V. parahaemolyticus virulence regulation by luxM/luxS-dependent quorum-sensing system.}, } @article {pmid29785216, year = {2018}, author = {Belyi, Y and Rybolovlev, I and Polyakov, N and Chernikova, A and Tabakova, I and Gintsburg, A}, title = {Staphylococcus Aureus Surface Protein G is An Immunodominant Protein and a Possible Target in An Anti-Biofilm Drug Development.}, journal = {The open microbiology journal}, volume = {12}, number = {}, pages = {94-106}, pmid = {29785216}, issn = {1874-2858}, abstract = {BACKGROUND: Staphylococcus aureus is a Gram-positive bacterium that causes severe illnesses in the human population. The capacity of S. aureus strains to form biofilms on biotic and abiotic surfaces creates serious problems for treatment of hospital infections and has stimulated efforts to develop new means of specific protection or immunotherapy.

MATERIAL AND METHODS: We found that rabbit serum raised against crude concentrated S. aureus liquid culture significantly decreased the development of staphylococcal biofilm in vitro. To discover the corresponding staphylococcal antigen, we used mass-spectrometry and molecular cloning and identified three major immunodominant proteins. They included α-haemolysin, serine proteinase SplB and S. aureus surface protein G, known as adhesin SasG.

RESULTS: Although according to literature data, all these proteins represent virulence factors of S. aureus and play diverse and important roles in the pathogenesis of staphylococcal diseases, only SasG can be directly implicated into the biofilm formation because of its surface location on a staphylococcal cell. Indeed, rabbit serum directed against purified recombinant SasG, similar to serum against crude staphylococcal liquid culture, prevented the formation of a biofilm.

CONCLUSION: SasG can be considered as a target in an anti-biofilm drug development and a component of the vaccine or immunotherapeutic preparations directed against staphylococcal infections in humans.}, } @article {pmid29785205, year = {2018}, author = {Ferone, M and Raganati, F and Ercole, A and Olivieri, G and Salatino, P and Marzocchella, A}, title = {Continuous succinic acid fermentation by Actinobacillus succinogenes in a packed-bed biofilm reactor.}, journal = {Biotechnology for biofuels}, volume = {11}, number = {}, pages = {138}, pmid = {29785205}, issn = {1754-6834}, abstract = {BACKGROUND: Succinic acid is one of the most interesting platform chemicals that can be produced in a biorefinery approach. In this study, continuous succinic acid production by Actinobacillus succinogenes fermentation in a packed-bed biofilm reactor (PBBR) was investigated.

RESULTS: The effects of the operating conditions tested, dilution rate (D), and medium composition (mixture of glucose, xylose, and arabinose-that simulate the composition of a lignocellulosic hydrolysate)-on the PBBR performances were investigated. The maximum succinic acid productivity of 35.0 g L[-1] h[-1] and the maximum SA concentration were achieved at a D = 1.9 h[-1]. The effect of HMF and furfural on succinic acid production was also investigated. HMF resulted to reduce succinic acid production by 22.6%, while furfural caused a reduction of 16% in SA production at the same dilution rate.

CONCLUSION: Succinic acid production by A. succinogenes fermentation in a packed-bed reactor (PBBR) was successfully carried out for more than 5 months. The optimal results were obtained at the dilution rate 0.5 h[-1]: 43.0 g L[-1] of succinic acid were produced, glucose conversion was 88%; and the volumetric productivity was 22 g L[-1] h[-1].}, } @article {pmid29784858, year = {2018}, author = {Sultan, AR and Swierstra, JW and Lemmens-den Toom, NA and Snijders, SV and Hansenová Maňásková, S and Verbon, A and van Wamel, WJB}, title = {Production of Staphylococcal Complement Inhibitor (SCIN) and Other Immune Modulators during the Early Stages of Staphylococcus aureus Biofilm Formation in a Mammalian Cell Culture Medium.}, journal = {Infection and immunity}, volume = {86}, number = {8}, pages = {}, pmid = {29784858}, issn = {1098-5522}, mesh = {Biofilms/*growth & development ; Complement Activation ; Complement Inactivating Agents/*metabolism ; Culture Media ; Gene Expression Profiling ; Humans ; Immunoassay ; Immunologic Factors/*metabolism ; Luminescent Measurements ; Mass Spectrometry ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*growth & development/isolation & purification/metabolism ; }, abstract = {Immune modulators are known to be produced by matured biofilms and during different stages of planktonic growth of Staphylococcus aureus Little is known about immune modulator production during the early stages of biofilm formation, thus raising the following question: how does S. aureus protect itself from the innate immune responses at these stages? Therefore, we determined the production of the following immune modulators: chemotaxis inhibitory protein of staphylococci (CHIPS); staphylococcal complement inhibitor (SCIN); formyl peptide receptor-like 1 inhibitor; gamma-hemolysin component B; leukocidins D, E, and S; staphylococcal superantigen-like proteins 1, 3, 5, and 9; and staphylococcal enterotoxin A. Production was determined during in vitro biofilm formation in Iscove's modified Dulbecco's medium at different time points using a competitive Luminex assay and mass spectrometry. Both methods demonstrated the production of the immune modulators SCIN and CHIPS during the early stages of biofilm formation. The green fluorescence protein promoter fusion technology confirmed scn (SCIN) and, to a lesser extent, chp (CHIPS) transcription during the early stages of biofilm formation. Furthermore, we found that SCIN could inhibit human complement activation induced by early biofilms, indicating that S. aureus is able to modulate the innate immune system already during the early stages of biofilm formation in vitro These results form a stepping stone toward elucidating the role of immune modulators in the establishment of biofilms in vivo and present opportunities to develop preventive strategies.}, } @article {pmid29784849, year = {2018}, author = {Jahanbakhsh, S and Singh, NB and Yim, J and Rose, WE and Rybak, MJ}, title = {Evaluation of Telavancin Alone and Combined with Ceftaroline or Rifampin against Methicillin-Resistant Staphylococcus aureus in an In Vitro Biofilm Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {8}, pages = {}, pmid = {29784849}, issn = {1098-6596}, support = {R01 AI132627/AI/NIAID NIH HHS/United States ; }, mesh = {Aminoglycosides/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Cephalosporins/*pharmacology ; Lipoglycopeptides/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Rifampin/*pharmacology ; }, abstract = {Infections caused by biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) bacteria are challenging due to increasing antibiotic resistance. Synergistic activities of lipopeptides and lipoglycopeptides with β-lactams have been demonstrated for MRSA, but little is known about biofilm-embedded organisms. Our objective was to evaluate two telavancin (TLV) dosage regimens (7.5 mg/kg of body weight and 10 mg/kg every 24 h [q24h]) alone and in combination with ceftaroline (CPT) (600 mg every 8 h [q8h]) or rifampin (RIF) (450 mg every 12 h [q12h]) against two biofilm-producing MRSA strains (494 and N315). Pharmacokinetic/pharmacodynamic CDC biofilm reactor models with polyurethane coupons were used to evaluate the efficacies of the antibiotic combinations over 72 h. Overall, there were no significant differences observed between the two TLV dosing regimens either alone or in combination with RIF or CPT against these strains. Both TLV dosing regimens and CPT alone demonstrated killing but did not reach bactericidal reduction at 72 h. However, both TLV regimens in combination with RIF demonstrated enhanced activity against both strains, with a rapid decrease in CFU/ml at 4 h that was bactericidal and maintained over the 72-h experiment (-Δ3.75 log10 CFU/ml from baseline; P < 0.0001). Of interest, no enhanced activity was observed for TLV combined with CPT. No development of resistance was observed in any of the combination models. However, resistance to RIF developed as early as 24 h, with MIC values exceeding 32 mg/liter. Our results show that TLV plus RIF displayed therapeutic improvement against biofilm-producing MRSA. These results suggest that TLV at 7.5 and 10 mg/kg q24h are equally effective in eradicating biofilm-associated MRSA strains in vitro.}, } @article {pmid29783128, year = {2018}, author = {Zhou, H and Sheng, Y and Zhao, X and Gross, M and Wen, Z}, title = {Treatment of acidic sulfate-containing wastewater using revolving algae biofilm reactors: Sulfur removal performance and microbial community characterization.}, journal = {Bioresource technology}, volume = {264}, number = {}, pages = {24-34}, doi = {10.1016/j.biortech.2018.05.051}, pmid = {29783128}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Sulfates ; Sulfur ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Industries such as mining operations are facing challenges of treating sulfur-containing wastewater such as acid mine drainage (AMD) generated in their plant. The aim of this work is to evaluate the use of a revolving algal biofilm (RAB) reactor to treat AMD with low pH (3.5-4) and high sulfate content (1-4 g/L). The RAB reactors resulted in sulfate removal efficiency up to 46% and removal rate up to 0.56 g/L-day, much higher than those obtained in suspension algal culture. The high-throughput sequencing revealed that the RAB reactor contained diverse cyanobacteria, green algae, diatoms, and acid reducing bacteria that contribute the sulfate removal through various mechanisms. The RAB reactors also showed a superior performance of COD, ammonia and phosphorus removal. Collectively, the study demonstrated that RAB-based process is an effective method to remove sulfate in wastewater with small footprint and can be potentially installed in municipal or industrial wastewater treatment facilities.}, } @article {pmid29781989, year = {2018}, author = {Nickerson, KP and Faherty, CS}, title = {Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {135}, pages = {}, pmid = {29781989}, issn = {1940-087X}, support = {K22 AI104755/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bacteria/*pathogenicity ; Bile Acids and Salts/*metabolism ; Biofilms/*growth & development ; Humans ; }, abstract = {Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, a significant stress response is induced during gastrointestinal transit and upon bile exposure, a normal component of human digestion. To overcome the bactericidal effects of bile, many enteric pathogens form a biofilm hypothesized to permit survival when transiting through the small intestine. Here we present methodologies to define biofilm formation through solid-phase adherence assays as well as extracellular polymeric substance (EPS) matrix detection and visualization. Furthermore, biofilm dispersion assessment is presented to mimic the analysis of events triggering release of bacteria during the infection process. Crystal violet staining is used to detect adherent bacteria in a high-throughput 96-well plate adherence assay. EPS production assessment is determined by two assays, namely microscopy staining of the EPS matrix and semi-quantitative analysis with a fluorescently-conjugated polysaccharide binding lectin. Finally, biofilm dispersion is measured through colony counts and plating. Positive data from multiple assays support the characterization of biofilms and can be utilized to identify bile salt-induced biofilm formation in other bacterial strains.}, } @article {pmid29781298, year = {2019}, author = {Ferreira-Filho, JCC and Marre, ATO and Almeida, JSS and Lobo, LA and Farah, A and Valença, AMG and Fonseca-Gonçalves, A}, title = {Treatment of dental biofilm with a tincture of Bauhinia forficata leaves: an ex-vivo study.}, journal = {Natural product research}, volume = {33}, number = {23}, pages = {3432-3435}, doi = {10.1080/14786419.2018.1477146}, pmid = {29781298}, issn = {1478-6427}, mesh = {Anti-Infective Agents/chemistry/*isolation & purification ; Bauhinia/*chemistry ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Healthy Volunteers ; Humans ; Plant Extracts/pharmacology ; Plant Leaves/chemistry ; Saliva/*microbiology ; }, abstract = {The inhibitory activity of a Bauhinia forficata tincture (TBF) was investigated against oral microorganism's strains and against a mature oral biofilm. The viability of planktonic cells was analyzed by Minimal Inhibitory and Microbicidal concentrations of TBF. Salivary samples from health volunteers were collected and mixed to form a saliva pool. An aliquot from this pool were seeded on membranes, which were incubated to form biofilm (48 h). The biofilm was treated according to the groups: G1-Chlorhexidine 0.12%; G2-TBF at the highest MMC; G3-Ethanol at the TBF highest MMC. G4 was the growth control. Streptococcus spp. (S) and total microorganisms (TM) from biofilm were counted. TBF was microbicidal against all oral pathogens. G2 was able to reduce the counts of S and TM from biofilm compared to G3 and G4, but less than G1 (p < 0.05). TBF is able to reduce the microbial levels from a mature oral biofilm.}, } @article {pmid29778633, year = {2018}, author = {Dabiri, S and Shams-Ghahfarokhi, M and Razzaghi-Abyaneh, M}, title = {Comparative analysis of proteinase, phospholipase, hydrophobicity and biofilm forming ability in Candida species isolated from clinical specimens.}, journal = {Journal de mycologie medicale}, volume = {28}, number = {3}, pages = {437-442}, doi = {10.1016/j.mycmed.2018.04.009}, pmid = {29778633}, issn = {1773-0449}, mesh = {Biofilms ; *Candida/enzymology/isolation & purification/pathogenicity/physiology ; Candidiasis/*microbiology ; Cross Infection/microbiology ; Female ; Humans ; Hydrophobic and Hydrophilic Interactions ; Male ; Peptide Hydrolases/analysis/isolation & purification/*metabolism ; Phospholipases/analysis/isolation & purification/*metabolism ; Virulence Factors/physiology ; }, abstract = {Candida species are the commensal organisms of human and animal mucosa that cause a wide range of debilitating diseases in immunocompromised patients and other susceptible individuals. The present study aimed to investigate the ability of clinical isolates of various Candida species to produce proteinase and phospholipase, hydrophobicity and biofilm forming ability that assumed to have a vital role in Candida pathogenicity. Eighty-four Candida strains belonged to Candida albicans (44.1%), C. glabrata (5.9%), C. guilliermondii (5.9%), C. krusei (10.8%), C. parapsilosis (26.2%), and C. tropicalis (7.1%) were examined for proteinase and phospholipase production, cell surface hydrophobicity and biofilm forming ability. The production of proteinase and phospholipase was detected in 81 (96.4%) and 79 (94.1%) of the strains, respectively. C. albicans showed the highest proteinase and phospholipase activity (mean Pz values of 0.42±0.25 and 0.72±0.28) and biofilm formation ability (0.66±0.22). C. parapsilosis had the highest hydrophobicity (42.97±16.1), which showed a good correlation with biofilm formation ability. A considerable percentage of non-albicans Candida strains produced significant amounts of proteinase and phospholipase with a good ability of biofilm formation in vitro. Taken together, our results further substantiated that enzymatic activity, hydrophobicity and the ability for biofilm formation are important virulence factors which may be account for pathogenicity of various Candida species distributed in albicans and non-albicans groups.}, } @article {pmid29778144, year = {2018}, author = {Tan, C and Xu, H and Cui, D and Zuo, J and Li, J and Ji, Y and Qiu, S and Yao, L and Chen, Y and Liu, Y}, title = {Effects of tourmaline on nitrogen removal performance and biofilm structures in the sequencing batch biofilm reactor.}, journal = {Journal of environmental sciences (China)}, volume = {67}, number = {}, pages = {127-135}, doi = {10.1016/j.jes.2017.08.012}, pmid = {29778144}, issn = {1001-0742}, mesh = {Biofilms/*drug effects/growth & development ; Nitrogen/analysis/*metabolism ; Silicates/*metabolism ; Waste Disposal, Fluid/*methods ; Water Pollutants/analysis/*metabolism ; }, abstract = {The effects of tourmaline on nitrogen removal performance and biofilm structures were comparatively investigated in two identical laboratory-scale sequencing batch biofilm reactors (SBBRs) (denoted SBBR1 and SBBR2) at different nitrogen loading rates (NLRs) varying from (0.24±0.01) to (1.26±0.02) g N/(L·day). SBBR1 was operated in parallel with SBBR2, but SBBR1 was filled with polyurethane foam loaded tourmaline (TPU) carriers and another (SBBR2) filled with polyurethane foam (PU) carriers. Results obtained from this study showed that the excellent and stable performance of SBBR1 was obtained. Ammonia nitrogen removal and total nitrogen removal were higher in SBBR1 than that in SBBR2 with increase of NLR. At an NLR of (0.24±0.01) g N/(L·day), the majority of the spherical and elliptical bacteria were surrounded by the extracellular polymeric substance (EPS) and bacillus or filamentous bacteria in two SBBRs biofilms. When NLR increased to (1.26±0.02) g N/(L·day), the clusters were more obvious in the SBBR1 biofilm than that in the SBBR2 biofilm. Bacteria in SBBR1 were inclined to synthesis more EPS, and the formed EPS could protect the bacteria from free ammonia (FA) under extreme condition NLR (1.26±0.02) g N/(L·day). The results of polymerase chain reaction-denaturing gradient gel electrophoresis analysis showed that the microbial community similarity in SBBR2 decreased more obviously than that in SBBR1 with the increase of NLR, which the microbial community in SBBR1 was relatively stable.}, } @article {pmid29777596, year = {2018}, author = {Rosenthal, AF and Griffin, JS and Wagner, M and Packman, AI and Balogun, O and Wells, GF}, title = {Morphological analysis of pore size and connectivity in a thick mixed-culture biofilm.}, journal = {Biotechnology and bioengineering}, volume = {115}, number = {9}, pages = {2268-2279}, doi = {10.1002/bit.26729}, pmid = {29777596}, issn = {1097-0290}, mesh = {Bacteria/*growth & development ; Biofilms/*growth & development ; Image Processing, Computer-Assisted/*methods ; Microbiological Techniques/*methods ; Optical Imaging/*methods ; Porosity ; }, abstract = {Morphological parameters are commonly used to predict transport and metabolic kinetics in biofilms. Yet, quantification of biofilm morphology remains challenging because of imaging technology limitations and lack of robust analytical approaches. We present a novel set of imaging and image analysis techniques to estimate internal porosity, pore size distributions, and pore network connectivity to a depth of 1 mm at a resolution of 10 µm in a biofilm exhibiting both heterotrophic and nitrifying activities. Optical coherence tomography (OCT) scans revealed an extensive pore network with diameters as large as 110 µm directly connected to the biofilm surface and surrounding fluid. Thin-section fluorescence in situ hybridization microscopy revealed that ammonia-oxidizing bacteria (AOB) distributed through the entire thickness of the biofilm. AOB were particularly concentrated in the biofilm around internal pores. Areal porosity values estimated from OCT scans were consistently lower than those estimated from multiphoton laser scanning microscopy, though the two imaging modalities showed a statistically significant correlation (r = 0.49, p < 0.0001). Estimates of areal porosity were moderately sensitive to gray-level threshold selection, though several automated thresholding algorithms yielded similar values to those obtained by manually thresholding performed by a panel of environmental engineering researchers (±25% relative error). These findings advance our ability to quantitatively describe the geometry of biofilm internal pore networks at length scales relevant to engineered biofilm reactors and suggest that internal pore structures provide crucial habitat for nitrifier growth.}, } @article {pmid29776923, year = {2018}, author = {Zhang, Y and Gao, J and Wang, L and Liu, S and Bai, Z and Zhuang, X and Zhuang, G}, title = {Environmental Adaptability and Quorum Sensing: Iron Uptake Regulation during Biofilm Formation by Paracoccus denitrificans.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {14}, pages = {}, pmid = {29776923}, issn = {1098-5336}, mesh = {Adaptation, Biological ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; *Biological Transport ; Gene Expression Regulation, Bacterial ; Iron/*metabolism ; Membrane Proteins/genetics ; Paracoccus denitrificans/growth & development/*metabolism ; Quorum Sensing/*physiology ; }, abstract = {Paracoccus denitrificans is a valuable model organism due to its versatile respiration capability and bioenergetic flexibility, both of which are critical to its survival in different environments. Quorum sensing (QS) plays a crucial role in the regulation of many cell functions; however, whether QS systems play a role in P. denitrificans is unknown. In this study, we demonstrated that iron uptake systems in P. denitrificans were directly regulated by a newly identified QS system. Genes coding for TonB-dependent systems, which transport chelated iron, were transcribed at higher levels in the QS-defective mutants. In contrast, genes coding for the Fbp system, which is TonB independent and transports unchelated ferric iron, were downregulated in the mutants. In brief, QS in P. denitrificans triggers a switch in iron uptake from TonB-dependent to TonB-independent transport during biofilm formation as higher concentrations of iron accumulate in the exopolysaccharide (EPS). Switching from TonB-dependent iron uptake systems to TonB-independent systems not only prevents cells from absorbing excess iron but also conserves energy. Our data suggest that iron uptake strategies are directly regulated by QS in Paracoccus denitrificans to support their survival in available ecological niches.IMPORTANCE As iron is an important trace metal for most organisms, its absorption is highly regulated. Fur has been reported as a prevalent regulator of iron acquisition. In addition, there is a relationship between QS and iron acquisition in pathogenic microbes. However, there have been few studies on the iron uptake strategies of nonpathogenic bacteria. In this study, we demonstrated that iron uptake systems in Paracoccus denitrificans PD1222 were regulated by a newly identified PdeR/PdeI QS system during biofilm formation, and we put forward a hypothesis that QS-dependent iron uptake systems benefit the stability of biofilms. This report elaborates the correlation among QS, iron uptake, and biofilm formation and thus contributes to an understanding of the ecological behavior of environmental bacteria.}, } @article {pmid29775684, year = {2018}, author = {Mesrati, I and Saidani, M and Jemili, M and Ferjeni, S and Slim, A and Boubaker, IB}, title = {Virulence determinants, biofilm production and antimicrobial susceptibility in Staphylococcus aureus causing device-associated infections in a Tunisian hospital.}, journal = {International journal of antimicrobial agents}, volume = {52}, number = {6}, pages = {922-929}, doi = {10.1016/j.ijantimicag.2018.05.004}, pmid = {29775684}, issn = {1872-7913}, mesh = {Biofilms/*growth & development ; Cross Infection/epidemiology/*microbiology ; Equipment and Supplies/*adverse effects ; Female ; Genes, Bacterial ; Genotype ; Genotyping Techniques ; Hospitals ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Staphylococcal Infections/epidemiology/*microbiology ; Staphylococcus aureus/classification/genetics/*isolation & purification ; Tunisia/epidemiology ; Virulence Factors/*genetics ; }, abstract = {Staphylococcus aureus is a clinically relevant pathogen that causes device-related infections (DRI) driven by several virulence factors. This study characterized S. aureus isolates involved in DRI in Tunisian patients. Forty consecutive S. aureus strains causing DRI and 47 randomly selected S. aureus strains causing non-device-related infections (NDRI) were collected. All strains were screened phenotypically for antibiotic susceptibility and biofilm forming ability. They were investigated for accessory gene regulator (agr) types, biofilm encoding genes (icaADBC), adhesins, leukotoxins, toxic shock toxin, enterotoxins and exotoxins encoding genes by polymerase chain reaction. Meticillin-resistant S. aureus (MRSA) strains were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing. MRSA rates among DRI and NDRI isolates were 23% and 49% (P=0.02), respectively. The DRI isolates formed biofilm more frequently (n=32) than the NDRI isolates (n=28) (P=0.04), with predominance of the moderate biofilm producer category (P=0.027). All biofilm-positive isolates except four harboured icaADBC genes. A significant difference was observed between DRI and NDRI isolates for fnbA (53-77%), spa (45-26%), sdrD (80-55%) and sen (33-11%) genes. DRI strains were agrI (48%) and agrII (30%) types, whereas NDRI strains were agrI (36%) and agrIII (43%) types. SCCmec type IV was carried by 50% of MRSA isolates. This study highlights the virulence potential displayed by S. aureus isolated from DRI in comparison with NDRI.}, } @article {pmid29775283, year = {2018}, author = {Abenojar, EC and Wickramasinghe, S and Ju, M and Uppaluri, S and Klika, A and George, J and Barsoum, W and Frangiamore, SJ and Higuera-Rueda, CA and Samia, ACS}, title = {Magnetic Glycol Chitin-Based Hydrogel Nanocomposite for Combined Thermal and d-Amino-Acid-Assisted Biofilm Disruption.}, journal = {ACS infectious diseases}, volume = {4}, number = {8}, pages = {1246-1256}, doi = {10.1021/acsinfecdis.8b00076}, pmid = {29775283}, issn = {2373-8227}, mesh = {Amino Acids/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development/*radiation effects ; Chitin/*analogs & derivatives/pharmacology ; Ferric Compounds/*pharmacology ; Hot Temperature ; *Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry ; Magnetic Fields ; Magnetics ; Nanocomposites/chemistry ; Staphylococcus aureus/drug effects/growth & development/radiation effects ; }, abstract = {Bacterial biofilms are highly antibiotic resistant microbial cell associations that lead to chronic infections. Unlike free-floating planktonic bacterial cells, the biofilms are encapsulated in a hardly penetrable extracellular polymeric matrix and, thus, demand innovative approaches for treatment. Recent advancements on the development of gel-nanocomposite systems with tailored therapeutic properties provide promising routes to develop novel antimicrobial agents that can be designed to disrupt and completely eradicate preformed biofilms. In our study, we developed a unique thermoresponsive magnetic glycol chitin-based nanocomposite containing d-amino acids and iron oxide nanoparticles, which can be delivered and undergoes transformation from a solution to a gel state at physiological temperature for sustained release of d-amino acids and magnetic field actuated thermal treatment of targeted infection sites. The d-amino acids in the hydrogel nanocomposite have been previously reported to inhibit biofilm formation and also disrupt existing biofilms. In addition, loading the hydrogel nanocomposite with magnetic nanoparticles allows for combination thermal treatment following magnetic field (magnetic hyperthermia) stimulation. Using this novel two-step approach to utilize an externally actuated gel-nanocomposite system for thermal treatment, following initial disruption with d-amino acids, we were able to demonstrate in vitro the total eradication of Staphylococcus aureus biofilms, which were resistant to conventional antibiotics and were not completely eradicated by separate d-amino acid or magnetic hyperthermia treatments.}, } @article {pmid29774013, year = {2018}, author = {Noirot-Gros, MF and Shinde, S and Larsen, PE and Zerbs, S and Korajczyk, PJ and Kemner, KM and Noirot, PH}, title = {Dynamics of Aspen Roots Colonization by Pseudomonads Reveals Strain-Specific and Mycorrhizal-Specific Patterns of Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {853}, pmid = {29774013}, issn = {1664-302X}, abstract = {Rhizosphere-associated Pseudomonas fluorescens are known plant growth promoting (PGP) and mycorrhizal helper bacteria (MHB) of many plants and ectomycorrhizal fungi. We investigated the spatial and temporal dynamics of colonization of mycorrhizal and non-mycorrhizal Aspen seedlings roots by the P. fluorescens strains SBW25, WH6, Pf0-1, and the P. protegens strain Pf-5. Seedlings were grown in laboratory vertical plates systems, inoculated with a fluorescently labeled Pseudomonas strain, and root colonization was monitored over a period of 5 weeks. We observed unexpected diversity of bacterial assemblies on seedling roots that changed over time and were strongly affected by root mycorrhization. P. fluorescens SBW25 and WH6 stains developed highly structured biofilms with internal void spaces forming channels. On mycorrhizal roots bacteria appeared encased in a mucilaginous substance in which they aligned side by side in parallel arrangements. The different phenotypic classes of bacterial assemblies observed for the four Pseudomonas strains were summarized in a single model describing transitions between phenotypic classes. Our findings also reveal that bacterial assembly phenotypes are driven by interactions with mucilaginous materials present at roots.}, } @article {pmid29772525, year = {2018}, author = {Campisciano, G and Zanotta, N and Petix, V and Corich, L and De Seta, F and Comar, M}, title = {Vaginal microbiota dysmicrobism and role of biofilm-forming bacteria.}, journal = {Frontiers in bioscience (Elite edition)}, volume = {10}, number = {3}, pages = {528-536}, doi = {10.2741/E839}, pmid = {29772525}, issn = {1945-0508}, mesh = {Adult ; Biofilms ; Female ; Humans ; *Microbiota ; Vagina/*microbiology ; Vaginosis, Bacterial/*microbiology ; }, abstract = {Bacterial vaginosis involves the presence of a polymicrobial biofilm on the vaginal epithelium, guaranteeing immune escape and spread of antibiotic resistance. To spot known biofilm-forming bacteria, we profiled the vaginal microbiome of sixty-four symptomatic women suffering from a different grade of vaginal disorders and sixty asymptomatic healthy women. Specific microbial profiles distinguished symptomatic from asymptomatic women and characterized the grade of dysmicrobism within the symptomatic group. Lactobacillus crispatus and iners predominated on the healthy vaginal mucosa, while Lactobacillus gasseri predominated in the intermediate dysmicrobism. Furthermore, the intermediate grade of dysmicrobism was characterized by other lactic acid-producers species than Lactobacilli, able to rescue the microbial imbalance, and Ureaplasma parvum-serovar 3. The vaginosis group exhibited the overgrowth of Prevotella bivia, which is known to enhance the biofilm formation by Gardnerella vaginalis, and the presence of Streptococcus anginosus, which is emerging as a new cooperating player of the vaginal biofilm. Identifying specific microorganisms promoting or preventing the biofilm formation could increase the accuracy for a better definition of the vaginal dysmicrobism concept and therapeutic intervention.}, } @article {pmid29772522, year = {2018}, author = {Campisciano, G and Cason, C and Palmisano, S and Giuricin, M and Rizzardi, A and Croce, LS and De Manzini, N and Comar, M}, title = {Bariatric surgery drives major rearrangements of the intestinal microbiota including the biofilm composition.}, journal = {Frontiers in bioscience (Elite edition)}, volume = {10}, number = {3}, pages = {495-505}, doi = {10.2741/E836}, pmid = {29772522}, issn = {1945-0508}, mesh = {Biofilms ; Case-Control Studies ; *Gastric Bypass ; *Gastrointestinal Microbiome ; Humans ; Intestinal Mucosa/*microbiology ; Obesity/*microbiology/surgery ; Prospective Studies ; }, abstract = {The intestinal microbiota disequilibrium has been associated with obesity, while the role of the gut mucosal biofilms in this pathology is still unknown. We analysed the changes in the intestinal microbiota of obese patients after bariatric surgery with the aim of disclosing the rearrangement of the biofilm configuration. Although the bariatric surgery drives major rearrangements of the gut microbiota, obese patients maintain the Prevotella enterotype before and after surgery, as shown by normal weight patients, with an increase of Bacteroides vulgatus and Bacteroides uniformis. The Bacteroides enterotype guarantees the strong ability to form a biofilm which allows a more efficient digestion of polysaccharides than planktonic communities and leads to the production of acetate which is a key player to inhibit enteropathogens. Additionally, the laparoscopic gastric bypass induces an increase of Hafniaalvei (Proteobacteria), a facultative anaerobic bacterium involved in intestinal and inflammatory disorders. Bariatric surgery influences the microbial composition of gut biofilm. Further studies are needed to elucidate the impact of this variation on recovery after surgery and on weight loss.}, } @article {pmid29771975, year = {2018}, author = {Kommerein, N and Doll, K and Stumpp, NS and Stiesch, M}, title = {Development and characterization of an oral multispecies biofilm implant flow chamber model.}, journal = {PloS one}, volume = {13}, number = {5}, pages = {e0196967}, pmid = {29771975}, issn = {1932-6203}, mesh = {Bacteria/*growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Humans ; *Models, Biological ; Mouth Mucosa/*microbiology ; }, abstract = {Peri-implant infections are the most common cause of implant failure in modern dental implantology. These are caused by the formation of biofilms on the implant surface and consist of oral commensal and pathogenic bacteria, which harm adjacent soft and hard tissues and may ultimately lead to implant loss. In order to improve the clinical situation, there has to be a better understanding of biofilm formation on abiotic surfaces. Therefore, we successfully developed a system to cultivate an oral multispecies biofilm model in a flow chamber system, optimized for the evaluation of biofilm formation on solid materials by direct microscopic investigation. The model contains four relevant oral bacterial species: Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis in ratios similar to the native situation. The reliability of the developed "Hanoverian Oral Multispecies Biofilm Implant Flow Chamber" (HOBIC) model was verified. Biofilm volume and live/dead distribution within biofilms were determined by fluorescence staining and confocal laser scanning microcopy (CLSM). The individual species distribution was analyzed using quantitative real time PCR with propidium monoazide pretreatment (PMA-qRT-PCR) and by urea-NaCl fluorescence in situ hybridization (urea-NaCl-FISH). This in vitro model may be used to analyze biofilm formation on dental implants in more detail and to develop future implant systems with improved material properties.}, } @article {pmid29771915, year = {2018}, author = {Pinweha, P and Pumirat, P and Cuccui, J and Jitprasutwit, N and Muangsombut, V and Srinon, V and Boonyuen, U and Thiennimitr, P and Vattanaviboon, P and Cia, F and Willcocks, S and Bancroft, GJ and Wren, BW and Korbsrisate, S}, title = {Inactivation of bpsl1039-1040 ATP-binding cassette transporter reduces intracellular survival in macrophages, biofilm formation and virulence in the murine model of Burkholderia pseudomallei infection.}, journal = {PloS one}, volume = {13}, number = {5}, pages = {e0196202}, pmid = {29771915}, issn = {1932-6203}, mesh = {ATP-Binding Cassette Transporters/genetics/*metabolism ; Anaerobiosis ; Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Burkholderia pseudomallei/genetics/metabolism/pathogenicity/*physiology ; Cell Survival ; Disease Models, Animal ; Female ; HeLa Cells ; Humans ; Intracellular Space/*microbiology ; Macrophages/cytology/*microbiology ; Melioidosis/*immunology ; Mice ; Mice, Inbred BALB C ; Mutation ; Nitrites/metabolism ; Phenotype ; Virulence ; }, abstract = {Burkholderia pseudomallei, a gram-negative intracellular bacillus, is the causative agent of a tropical infectious disease called melioidosis. Bacterial ATP-binding cassette (ABC) transporters import and export a variety of molecules across bacterial cell membranes. At present, their significance in B. pseudomallei pathogenesis is poorly understood. We report here characterization of the BPSL1039-1040 ABC transporter. B. pseudomallei cultured in M9 medium supplemented with nitrate, demonstrated that BPSL1039-1040 is involved in nitrate transport for B. pseudomallei growth under anaerobic, but not aerobic conditions, suggesting that BPSL1039-1040 is functional under reduced oxygen tension. In addition, a nitrate reduction assay supported the function of BPSL1039-1040 as nitrate importer. A bpsl1039-1040 deficient mutant showed reduced biofilm formation as compared with the wild-type strain (P = 0.027) when cultured in LB medium supplemented with nitrate under anaerobic growth conditions. This reduction was not noticeable under aerobic conditions. This suggests that a gradient in oxygen levels could regulate the function of BPSL1039-1040 in B. pseudomallei nitrate metabolism. Furthermore, the B. pseudomallei bpsl1039-1040 mutant had a pronounced effect on plaque formation (P < 0.001), and was defective in intracellular survival in both non-phagocytic (HeLa) and phagocytic (J774A.1 macrophage) cells, suggesting reduced virulence in the mutant strain. The bpsl1039-1040 mutant was found to be attenuated in a BALB/c mouse intranasal infection model. Complementation of the bpsl1039-1040 deficient mutant with the plasmid-borne bpsl1039 gene could restore the phenotypes observed. We propose that the ability to acquire nitrate for survival under anaerobic conditions may, at least in part, be important for intracellular survival and has a contributory role in the pathogenesis of B. pseudomallei.}, } @article {pmid29769768, year = {2018}, author = {Hari, P and Kacharaju, KR and Anumala, N and Pathakota, KR and Avula, J}, title = {Application of bioelectric effect to reduce the antibiotic resistance of subgingival plaque biofilm: An in vitro study.}, journal = {Journal of Indian Society of Periodontology}, volume = {22}, number = {2}, pages = {133-139}, pmid = {29769768}, issn = {0972-124X}, abstract = {CONTEXT: Biofilms are known for their antimicrobial resistance, and so is the subgingival plaque biofilm, the primary etiologic factor for periodontal infections.

AIMS: The objective of this study is to investigate if the subgingival plaque biofilm resistance can be reduced using doxycycline in the presence of low-intensity electric field (bioelectric effect).

SETTINGS AND DESIGN: The study was an in vitro microbiological study.

MATERIALS AND METHODS: Subgingival plaque samples from chronic periodontitis patients were collected to grow subgingival plaque biofilms on hydroxyapatite disks. Hydroxyapatite disks with the plaque biofilms from each patient were divided into four groups: (i) No intervention - control, (ii) current alone - CU; (iii) doxycycline - AB, and (iv) combined treatment - CU + AB. After respective treatments, the disks were anaerobically incubated for 48 h, the biofilm was dispersed and subcultured and colony-forming unit/mL was estimated in all the four groups.

STATISTICAL ANALYSIS: Statistical analysis was done using Mann-Whitney and Kruskal-Wallis tests for intergroup comparisons. T-test was done to assess the difference in current flow between the groups CU and CU + AB.

RESULTS: All the three treatment modalities showed antibacterial effect. Application of current alone resulted in reduced bacterial growth than control group. Doxycycline alone resulted in reduction in bacterial counts better than control and current alone groups. The combination treatment showed greatest inhibition of bacterial colonies.

CONCLUSION: The ability of doxycycline antibiotic in inhibiting plaque biofilm was significantly enhanced by application of a weak electric field (5 volts for 2 min).}, } @article {pmid29769381, year = {2018}, author = {Luterbach, CL and Forsyth, VS and Engstrom, MD and Mobley, HLT}, title = {TosR-Mediated Regulation of Adhesins and Biofilm Formation in Uropathogenic Escherichia coli.}, journal = {mSphere}, volume = {3}, number = {3}, pages = {}, pmid = {29769381}, issn = {2379-5042}, support = {R01 DK094777/DK/NIDDK NIH HHS/United States ; R01 AI116791/AI/NIAID NIH HHS/United States ; R01 AI059722/AI/NIAID NIH HHS/United States ; R56 AI043363/AI/NIAID NIH HHS/United States ; R01 AI043363/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Escherichia coli/*biosynthesis ; Biofilms/*growth & development ; Escherichia coli Proteins/*metabolism ; Gene Deletion ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Genetic Complementation Test ; Metabolic Networks and Pathways/genetics ; Real-Time Polymerase Chain Reaction ; Regulon ; Repressor Proteins/*metabolism ; Uropathogenic Escherichia coli/*genetics/*physiology ; }, abstract = {Uropathogenic Escherichia coli strains utilize a variety of adherence factors that assist in colonization of the host urinary tract. TosA (type one secretion A) is a nonfimbrial adhesin that is predominately expressed during murine urinary tract infection (UTI), binds to kidney epithelial cells, and promotes survival during invasive infections. The tosRCBDAEF operon encodes the secretory machinery necessary for TosA localization to the E. coli cell surface, as well as the transcriptional regulator TosR. TosR binds upstream of the tos operon and in a concentration-dependent manner either induces or represses tosA expression. TosR is a member of the PapB family of fimbrial regulators that can participate in cross talk between fimbrial operons. TosR also binds upstream of the pap operon and suppresses PapA production. However, the scope of TosR-mediated cross talk is understudied and may be underestimated. To quantify the global effects of TosR-mediated regulation on the E. coli CFT073 genome, we induced expression of tosR, collected mRNA, and performed high-throughput RNA sequencing (RNA-Seq). These findings show that production of TosR affected the expression of genes involved with adhesins, including P, F1C, and Auf fimbriae, nitrate-nitrite transport, microcin secretion, and biofilm formation.IMPORTANCE Uropathogenic E. coli strains cause the majority of UTIs, which are the second most common bacterial infection in humans. During a UTI, bacteria adhere to cells within the urinary tract, using a number of different fimbrial and nonfimbrial adhesins. Biofilms can also develop on the surfaces of catheters, resulting in complications such as blockage. In this work, we further characterized the regulator TosR, which links both adhesin production and biofilm formation and likely plays a crucial function during UTI and disseminated infection.}, } @article {pmid29768730, year = {2018}, author = {Galli, J and Calo, L and Meucci, D and Giuliani, M and Lucidi, D and Paludetti, G and Torelli, R and Sanguinetti, M and Parrilla, C}, title = {Biofilm in voice prosthesis: A prospective cohort study and laboratory tests using sonication and SEM analysis.}, journal = {Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery}, volume = {43}, number = {5}, pages = {1260-1265}, doi = {10.1111/coa.13141}, pmid = {29768730}, issn = {1749-4486}, mesh = {*Biofilms ; Candida albicans/*isolation & purification ; Cohort Studies ; Colony Count, Microbial ; Haemophilus influenzae/*isolation & purification ; Humans ; Laryngectomy ; Larynx, Artificial/*microbiology ; Microscopy, Electron, Scanning ; Polytetrafluoroethylene ; Prosthesis Design ; Prosthesis Failure ; Silicones ; Sonication ; Staphylococcus/*isolation & purification ; Streptococcus/*isolation & purification ; }, abstract = {OBJECTIVE: The objective of the study was to compare the biofilm growing pattern and its morphological extent on silicone and a teflon-like material using a sonication process and a Scanning Electron Microscope (SEM).

DESIGN: A prospective cohort study and a laboratory study.

SETTING: Otolaryngology -Head and Neck surgery Department and the Microbiology Institute.

PARTICIPANTS: The participants included fifteen laryngectomised patients with phonatory prostheses, which were removed because of device failure, and two different kinds of phonatory prostheses from the laboratory (Provox 2 and ActiValve) that were artificially colonised by Candida albicans.

MAIN OUTCOME MEASURES: Tracheo-oesophageal puncture (TEP) is currently considered the gold standard for post-laryngectomy voice rehabilitation. "Leakage" represents the most common cause of substitution and is generated by biofilm colonisation of the prosthesis by mixed mycotic and bacterial agents. New biomaterials have been developed that are deemed to be more resistant to the colonisation of micro-organisms and material deformation.

RESULTS: The devices showed colonisation by mixed bacterial flora (Staphylococci 13%, Streptococci 9%, and Haemophilus influenzae 5%) and by yeasts (Candida albicans 12%). Moreover, we observed a different distribution of biofilm layers in Provox ActiValve (22.56%) compared to Provox 2 (56.82%) after experimental colonisation by the previously isolated Candida strain.

CONCLUSION: Resident microbiological species from the upper airways unavoidably colonise the polymer surfaces, and no strategies have been effective except for the manipulation of the chemical-physical properties of the device's polymer. Our study confirms that Provox ActiValve, which is made with a fluoroplastic material (teflon-like), is less subject to in vitro colonisation by Candida, and thus showed a higher clinical resistance to biofilm and a longer lifespan. The sonication seems to significantly improve the knowledge of bacterial and mycotic flora in biofilm colonisation. The design of a device for the daily cleaning capable to reach and brush the oesophageal flange of the prosthesis preserving the valve mechanism could represent a practical and simple help in this still unsolved problem.}, } @article {pmid29767954, year = {2018}, author = {Ma, L and Feng, S and Fuente-Núñez, C and Hancock, REW and Lu, X}, title = {Development of Molecularly Imprinted Polymers To Block Quorum Sensing and Inhibit Bacterial Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {22}, pages = {18450-18457}, doi = {10.1021/acsami.8b01584}, pmid = {29767954}, issn = {1944-8252}, mesh = {Biofilms ; Lactones ; Polymers ; Pseudomonas aeruginosa ; *Quorum Sensing ; }, abstract = {Bacterial biofilms are responsible for most clinical infections and show increased antimicrobial resistance. In this study, molecularly imprinted polymers (MIPs) were developed to specifically capture prototypical quorum sensing autoinducers [i.e., N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12AHL)], interrupt quorum sensing, and subsequently inhibit biofilm formation of Pseudomonas aeruginosa, an important human nosocomial pathogen. The synthesis of MIPs was optimized by considering the amount and type of the functional monomers itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA). IA-based MIPs showed high adsorption affinity toward 3-oxo-C12AHL with an imprinting factor of 1.68. Compared to IA-based MIPs, the adsorption capacity of HEMA-based MIPs was improved fivefold. HEMA-based MIPs significantly reduced biofilm formation (by ∼65%), whereas biofilm suppression by IA-based MIPs was neutralized because of increased bacterial attachment. The developed MIPs represent promising alternative biofilm intervention agents that can be applied to surfaces relevant to clinical settings and food processing equipment.}, } @article {pmid29767615, year = {2018}, author = {Singh, R and Kumari, A and Kaur, K and Sethi, P and Chakrabarti, A}, title = {Relevance of antifungal penetration in biofilm-associated resistance of Candida albicans and non-albicans Candida species.}, journal = {Journal of medical microbiology}, volume = {67}, number = {7}, pages = {922-926}, doi = {10.1099/jmm.0.000757}, pmid = {29767615}, issn = {1473-5644}, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Candida albicans/*drug effects/physiology ; Candidiasis/microbiology ; *Drug Resistance, Fungal ; Humans ; Voriconazole/pharmacology ; }, abstract = {The role of penetration limitation in Candida biofilm-associated antifungal resistance remains unclear. Most of the previous work has been done on Candida albicans, although non-albicans (NAC) species are also implicated in invasive candidiasis and the biofilm matrix has been shown to vary amongst different species. Only a few studies have evaluated clinical isolates. This study aimed to determine the relevance of penetration limitation in the antifungal resistance of biofilms formed by C. albicans and NAC clinical isolates, using an agar disk diffusion assay. The penetration of posaconazole and amphotericin B through the biofilms was significantly reduced. Fluconazole, voriconazole and caspofungin showed a superior penetration capacity in C. albicans, Candida tropicalis and Candida parapsilosis biofilms, but exhibited inter-species and strain/isolate variation. Candida krusei biofilms were the most resilient to antifungal permeation. All of the antifungal drugs failed to kill the biofilm cells, independent of penetration, suggesting that the other factors contribute markedly to the recalcitrance of the biofilms.}, } @article {pmid29766261, year = {2018}, author = {Celik, A and Tunc, MS and Hanay, O and Taskan, E and Hasar, H}, title = {Comprehensive evaluation of autohydrogenotrophic membrane biofilm reactor treating OTC-enriched water medium.}, journal = {Bioprocess and biosystems engineering}, volume = {41}, number = {9}, pages = {1261-1269}, doi = {10.1007/s00449-018-1954-8}, pmid = {29766261}, issn = {1615-7605}, mesh = {Bacteria/*growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Bioreactors ; *Membranes, Artificial ; Oxytetracycline/*metabolism ; *Water Microbiology ; }, abstract = {In the recent years, there has been considerable debate about the potential impacts of antibiotics present in various environments on the public health and ecology. Oxytetracycline (OTC) is one of tetracycline antibiotic group used for growth and treatment of animals and humans. In this study, OTC and nitrate (NO3-N) were simultaneously reduced using a hydrogen-based membrane biofilm reactor (H2-MBfR). The system successfully accomplished OTC and nitrate removals. The fluxes of OTC and NO3-N were 8.96 mg OTC/m[2] day and 1100 mg N/m[2] day, respectively. On the other hand, the fluxes of H2 utilized for OTC and NO3-N reductions were calculated as maximum values of 1.71 and 395 mg H2/m[2] day, respectively. The concentrations of transformation products of OTC formed at ppb levels. The dominant species in all the experimental periods with OTC biodegradation referred to Naxibacter sp., Uncultured Beta proteobacterium, Janthinobacterium sp. and Alicycliphilus denitrificans in autotrophic biofilm community degrading OTC.}, } @article {pmid29765621, year = {2018}, author = {Yu, S and Zhu, X and Zhou, J and Cai, Z}, title = {Biofilm inhibition and pathogenicity attenuation in bacteria by Proteus mirabilis.}, journal = {Royal Society open science}, volume = {5}, number = {4}, pages = {170702}, pmid = {29765621}, issn = {2054-5703}, abstract = {Biofilms play an important role in the antibiotic resistance of encased bacteria, and biofilm formation is regulated by quorum sensing (QS). Inhibiting the QS system may, therefore, degrade the integrity of a biofilm and expose the bacterial pathogens within it to the deleterious effects of molecules such as antibiotics. Moreover, the use of QS inhibitors (QSIs) may provide a novel approach for treating bacterial infections of aquacultures. In the present study, the bacterium Proteus mirabilis was identified as a potential producer of QSIs. Varying concentrations (0.1-1.1%) of filtrates prepared from the culture of P. mirabilis inhibited biofilm formation by the pathogens Pseudomonas aeruginosa, Vibrio harveyi and Staphylococcus aureus by as much as 58.9%, 41.5% and 41.9%, respectively. These filtrates as well as the crude aqueous extracts prepared from them increased the sensitivities of pathogens to the inhibitory effects of kanamycin. The filtrates also showed pathogenicity attenuation potential in P. aeruginosa by decreasing the production of virulence factors. Moreover, the filtrates did not influence the planktonic growth of these pathogens. The results indicate that P. mirabilis may act as a non-specific (or broad-spectrum) inhibitor of biofilm formation that will help control infectious diseases that adversely affect the aquaculture industry.}, } @article {pmid29764945, year = {2018}, author = {Lattar, SM and Wu, X and Brophy, J and Sakai, F and Klugman, KP and Vidal, JE}, title = {A Mechanism of Unidirectional Transformation, Leading to Antibiotic Resistance, Occurs within Nasopharyngeal Pneumococcal Biofilm Consortia.}, journal = {mBio}, volume = {9}, number = {3}, pages = {}, pmid = {29764945}, issn = {2150-7511}, support = {R21 AI112768/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; *Drug Resistance, Bacterial ; Humans ; Microbial Consortia ; Microbial Sensitivity Tests ; Nasopharynx/*microbiology ; Pneumococcal Infections/*microbiology ; Streptococcus pneumoniae/*drug effects/*genetics/physiology ; Transformation, Genetic ; }, abstract = {Streptococcus pneumoniae acquires genes for resistance to antibiotics such as streptomycin (Str) or trimethoprim (Tmp) by recombination via transformation of DNA released by other pneumococci and closely related species. Using naturally transformable pneumococci, including strain D39 serotype 2 (S2) and TIGR4 (S4), we studied whether pneumococcal nasopharyngeal transformation was symmetrical, asymmetrical, or unidirectional. Incubation of S2[Tet] and S4[Str] in a bioreactor simulating the human nasopharynx led to the generation of Spn[Tet/Str] recombinants. Double-resistant pneumococci emerged soon after 4 h postinoculation at a recombination frequency (rF) of 2.5 × 10[-4] while peaking after 8 h at a rF of 1.1 × 10[-3] Acquisition of antibiotic resistance genes by transformation was confirmed by treatment with DNase I. A high-throughput serotyping method demonstrated that all double-resistant pneumococci belonged to one serotype lineage (S2[Tet/Str]) and therefore that unidirectional transformation had occurred. Neither heterolysis nor availability of DNA for transformation was a factor for unidirectional transformation given that the density of each strain and extracellular DNA (eDNA) released from both strains were similar. Unidirectional transformation occurred regardless of the antibiotic-resistant gene carried by donors or acquired by recipients and regardless of whether competence-stimulating peptide-receptor cross talk was allowed. Moreover, unidirectional transformation occurred when two donor strains (e.g., S4[Str] and S19F[Tmp]) were incubated together, leading to S19F[Str/Tmp] but at a rF 3 orders of magnitude lower (4.9 × 10[-6]). We finally demonstrated that the mechanism leading to unidirectional transformation was due to inhibition of transformation of the donor by the recipient.IMPORTANCE Pneumococcal transformation in the human nasopharynx may lead to the acquisition of antibiotic resistance genes or genes encoding new capsular variants. Antibiotics and vaccines are currently putting pressure on a number of strains, leading to an increase in antibiotic resistance and serotype replacement. These pneumococcal strains are also acquiring virulence traits from vaccine types via transformation. In this study, we recapitulated multiple-strain colonization with strains carrying a resistance marker and selected for those acquiring resistance to two or three antibiotics, such as would occur in the human nasopharynx. Strains acquiring dual and triple resistance originated from one progenitor, demonstrating that transformation was unidirectional. Unidirectional transformation was the result of inhibition of transformation of donor strains. Unidirectional transformation has implications for the understanding of acquisition patterns of resistance determinants or capsule-switching events.}, } @article {pmid29763807, year = {2018}, author = {Pulido, D and Prats-Ejarque, G and Villalba, C and Albacar, M and Moussaoui, M and Andreu, D and Volkmer, R and Torrent, M and Boix, E}, title = {Positional scanning library applied to the human eosinophil cationic protein/RNase3 N-terminus reveals novel and potent anti-biofilm peptides.}, journal = {European journal of medicinal chemistry}, volume = {152}, number = {}, pages = {590-599}, doi = {10.1016/j.ejmech.2018.05.012}, pmid = {29763807}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line, Tumor ; Cell Membrane/drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Eosinophil Cationic Protein/*antagonists & inhibitors/metabolism ; Hep G2 Cells ; Humans ; Lipopolysaccharides/chemistry/metabolism ; Molecular Structure ; *Peptide Library ; Pseudomonas aeruginosa/cytology/*drug effects/metabolism ; Structure-Activity Relationship ; }, abstract = {Eradication of established biofilm communities of pathogenic bacteria is one of the pending challenges in the development of new antimicrobial agents. In particular, the dreaded nosocomial Pseudomonas aeruginosa forms microbial communities that offer an enhanced resistance to conventional antibiotics. Recently, we have described an engineered antimicrobial peptide derived from the human RNase3, also named the eosinophil cationic protein (ECP), RN3 (5-36), which combines bactericidal activity with high cell agglutination and lipopolysaccharide (LPS) affinity. Through a single replacement scan library using the SPOT methodology we have evaluated both the contribution of sequence positioning and amino acid singularity towards the peptide biological and physicochemical properties. Results indicate that the ECP N-terminus has already been extensively improved through evolution to provide high antimicrobial activity; hence most substitutions improving its antimicrobial performance are in detriment of safety towards host tissues. Only three positions were identified, occupied by polar residues on the first α-helix of the protein and replaceable by a hydrophobic residue, allowing an extended N-terminal patch that mediates bacterial agglutination. Among the best candidates, an Ile replacement proved best in improving the peptide therapeutic window. The novel engineered peptides encompass both the LPS-binding and aggregation-prone regions of parental ECP, providing the appropriate structural features for peptide attachment to the bacterial exopolysaccharide layer and bacterial cell membrane destabilization, thereby promoting biofilm removal at micro molar concentrations. We conclude that the novel engineered peptides are promising lead candidates against Gram-negative biofilms.}, } @article {pmid29763755, year = {2018}, author = {De Abrew Abeysundara, P and Dhowlaghar, N and Nannapaneni, R and Schilling, MW and Mahmoud, B and Sharma, CS and Ma, DP}, title = {Salmonella enterica growth and biofilm formation in flesh and peel cantaloupe extracts on four food-contact surfaces.}, journal = {International journal of food microbiology}, volume = {280}, number = {}, pages = {17-26}, doi = {10.1016/j.ijfoodmicro.2018.04.042}, pmid = {29763755}, issn = {1879-3460}, mesh = {Biofilms/*growth & development ; Cucumis melo/*microbiology ; Food Handling ; Food Microbiology ; Foodborne Diseases/*microbiology ; Plant Extracts/*pharmacology ; Salmonella enterica/*growth & development ; }, abstract = {Salmonella enterica is responsible for the highest number of foodborne disease outbreaks pertaining to cantaloupe industry. The objective of this study was to examine the growth and biofilm formation by outbreak strains of S. enterica ser. Poona (S. Poona), S. enterica ser. Stanley (S. Stanley) and S. enterica ser. Montevideo (S. Montevideo) on different food-contact processing surfaces in cantaloupe flesh and peel extracts at 22 °C and 10 °C. The generation time of all S. enterica strains tested was shorter in the high concentration (50 mg/ml) of cantaloupe extract and high temperature. In 50 mg/ml of cantaloupe flesh or peel extract, the populations of S. enterica were increased by 5 log CFU/ml in 24 h at 22 °C and 1 log CFU/ml in 72 h at 10 °C. In 2 mg/ml of cantaloupe flesh or peel extracts, the populations of S. enterica were increased by 3.5 log CFU/ml in 56 h at 22 °C, but there were no changes in 72 h at 10 °C. The biofilm production of S. enterica was greater at 50 mg/ml of cantaloupe extract and 22 °C, but no major differences (P ≥ 0.05) were found among the strains tested. In 50 mg/ml cantaloupe extract, S. enterica produced 5-6 log CFU/cm[2] biofilm in 4-7 d at 22 °C and approximately 3.5-4 log CFU/cm[2] in 7 d at 10 °C. In 2 mg/ml of cantaloupe extract, S. enterica produced 4-4.5 log CFU/cm[2] biofilms in 4-7 d at 22 °C and 3 log CFU/cm[2] in 7 d at 10 °C. Biofilm formation by S. Poona (01A4754) was lowest on buna-n rubber compared to stainless steel, polyethylene and polyurethane surfaces under the majority of conditions tested. Overall, these findings show that S. enterica strains can grow rapidly and form biofilms on different cantaloupe processing surfaces in the presence of low concentrations of cantaloupe flesh or peel extracts.}, } @article {pmid29763739, year = {2018}, author = {Tokubo, LM and Rosalen, PL and de Cássia Orlandi Sardi, J and Freires, IA and Fujimaki, M and Umeda, JE and Barbosa, PM and Tecchio, GO and Hioka, N and de Freitas, CF and Suga Terada, RS}, title = {Antimicrobial effect of photodynamic therapy using erythrosine/methylene blue combination on Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {23}, number = {}, pages = {94-98}, doi = {10.1016/j.pdpdt.2018.05.004}, pmid = {29763739}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Drug Combinations ; Erythrosine/administration & dosage/*pharmacology ; Methylene Blue/administration & dosage/*pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {BACKGROUND: Photodynamic therapy (PDT) has demonstrated promising results in the treatment of several clinical pathologies through the photochemical reaction caused by the combination of a photosensitizer and a light source. The objective of this study was to evaluate the antimicrobial effect of the combination of the photosensitizers (PSs) erythrosine/methylene blue activated by a white halogen light device on Streptococcus mutans biofilm.

METHODS: Two separate experiments were conducted, the first using the PSs at the concentration of 100 μM, and the second 250 μM. The PSs were tested on S. mutans biofilms cultured for 24 h in isolation, in combination, with and without light activation for 2 min fractionated in 4 periods of 30 s. After treatment, biofilms were diluted and plated on BHI medium and incubated for 24 h for colony forming units (CFU) counting. The results (log10) were analyzed with ANOVA followed by Tukey test (p < 0.05).

RESULTS: The erythrosine/methylene blue combination activated by white halogen light at 100 and 250 μM, and erythrosine at 250 μM, methylene blue at 250 μM presented significantly reduced cell counts (3.2 log10, 5.3 log10, 4.5 log10, 4.3 log10, respectively) when compared to controls (p < 0.05).

CONCLUSION: PDT with the combination of erythrosine/methylene blue demonstrated better results that the PSs in isolation regardless of the concentration. The use of this combination at the concentration of 250 μM shows promise as an antibacterial treatment for carious lesions and should be further assessed.}, } @article {pmid29763730, year = {2018}, author = {Almeida, FA and Vargas, ELG and Carneiro, DG and Pinto, UM and Vanetti, MCD}, title = {Virtual screening of plant compounds and nonsteroidal anti-inflammatory drugs for inhibition of quorum sensing and biofilm formation in Salmonella.}, journal = {Microbial pathogenesis}, volume = {121}, number = {}, pages = {369-388}, doi = {10.1016/j.micpath.2018.05.014}, pmid = {29763730}, issn = {1096-1208}, mesh = {Acyl-Butyrolactones/metabolism ; Anti-Inflammatory Agents, Non-Steroidal/analysis/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; *Gene Expression Regulation, Bacterial ; Molecular Docking Simulation ; Plant Extracts/pharmacology ; Quorum Sensing/*drug effects ; Salmonella enteritidis/drug effects/*genetics/physiology ; Trans-Activators/genetics/metabolism ; Transcription Factors/genetics/metabolism ; }, abstract = {Salmonella belongs to the Enterobacteriaceae family which is widely distributed in the environment due to its adaptive capacity to stress conditions. In addition, Salmonella is able to perform a type of cell-to-cell communication called quorum sensing, which leads to differential gene expression. The quorum sensing system mediated by AI-1, acyl homoserine lactones (AHLs), is incomplete in Salmonella because the luxI homolog gene, which encodes for AI-1 synthase, is missing in the genome. However, a homologue of LuxR, known as SdiA, is present and allows the detection of signaling molecules produced by other species of bacteria, leading to regulation of gene expression, mainly related to virulence and biofilm formation. Thus, in view of the importance of quorum sensing on the physiology regulation of microorganisms, the aim of the present study was to perform a virtual screening of plant compounds and nonsteroidal anti-inflammatory drugs (NASIDs) for inhibition of quorum sensing by molecular docking and biofilm formation in Salmonella. In general, most plant compounds and all NSAIDs bound in, at least, one of the three modeled structures of SdiA proteins of Salmonella Enteritidis PT4 578. In addition, many tested compounds had higher binding affinities than the AHLs and the furanones which are inducers and inhibitors of quorum sensing, respectively. The Z-phytol and lonazolac molecules were good candidates for the in vitro inhibition tests of quorum sensing mediated by AI-1 and biofilm formation in Salmonella. Thus, this study directs future prospecting of plant extracts for inhibition of quorum sensing mechanism depending on AHL and biofilm formation. In addition, the use of inhibitors of quorum sensing and biofilm formation can be combined with antibiotics for better treatment efficacy, as well as the use of these compounds to design new drugs.}, } @article {pmid29763724, year = {2018}, author = {Nie, S and Lu, X and Hu, YW and Zheng, L and Wang, Q}, title = {Influence of environmental and genotypic factors on biofilm formation by clinical isolates of group B streptococci.}, journal = {Microbial pathogenesis}, volume = {121}, number = {}, pages = {45-50}, doi = {10.1016/j.micpath.2018.05.020}, pmid = {29763724}, issn = {1096-1208}, mesh = {Batch Cell Culture Techniques ; Biofilms/*growth & development ; Fimbriae, Bacterial/genetics/metabolism ; Genotype ; Hydrogen-Ion Concentration ; Logistic Models ; Phenotype ; Streptococcus agalactiae/*genetics/growth & development ; }, abstract = {Group B Streptococcus (GBS) colonizes the gastrointestinal and urogenital tracts of approximately 30% of women, and it can cause sepsis and meningitis in neonates. GBS has been shown to form biofilms in vitro, but the effects of environmental and genotypic factors upon GBS biofilm formation are unclear. The aim of the present study was to optimize culture conditions for enhanced GBS biofilm production. Furthermore, this study also investigated the influences of strain lineage, pilus profile, and isolation source on GBS biofilm formation. The results demonstrate that the fed-batch mode and acidic pH strongly enhanced GBS biofilm formation in vitro. These findings suggest that the fed-batch mode may be suitable for both screening and fundamental studies of GBS biofilm formation. Moreover, this study demonstrated a correlation between the hyper virulent clonal complex 17 and a strong biofilm phenotype.}, } @article {pmid29762495, year = {2018}, author = {Culler, HF and Couto, SCF and Higa, JS and Ruiz, RM and Yang, MJ and Bueris, V and Franzolin, MR and Sircili, MP}, title = {Role of SdiA on Biofilm Formation by Atypical Enteropathogenic Escherichia coli.}, journal = {Genes}, volume = {9}, number = {5}, pages = {}, pmid = {29762495}, issn = {2073-4425}, abstract = {Atypical enteropathogenic Escherichia coli are capable to form biofilm on biotic and abiotic surfaces, regardless of the adherence pattern displayed. Several E. coli mechanisms are regulated by Quorum sensing (QS), including virulence factors and biofilm formation. Quorum sensing is a signaling system that confers bacteria with the ability to respond to chemical molecules known as autoinducers. Suppressor of division inhibitor (SdiA) is a QS receptor present in atypical enteropathogenic E.coli (aEPEC) that detects acyl homoserine lactone (AHL) type autoinducers. However, these bacteria do not encode an AHL synthase, but they are capable of sensing AHL molecules produced by other species, establishing an inter-species bacterial communication. In this study, we performed experiments to evaluate pellicle, ring-like structure and biofilm formation on wild type, sdiA mutants and complemented strains. We also evaluated the transcription of genes involved in different stages of biofilm formation, such as bcsA, csgA, csgD, fliC and fimA. The sdiA mutants were capable of forming thicker biofilm structures and showed increased motility when compared to wild type and complemented strains. Moreover, they also showed denser pellicles and ring-like structures. Quantitative real-time PCR (qRT-PCR) analysis demonstrated increased csgA, csgD and fliC transcription on mutant strains. Biofilm formation, as well as csgD, csgA and fimA transcription decreased on wild type strains by the addition of AHL. These results indicate that SdiA participates on the regulation of these phenotypes in aEPEC and that AHL addition enhances the repressor effect of this receptor on the transcription of biofilm and motility related genes.}, } @article {pmid29760209, year = {2018}, author = {Chodur, DM and Rowe-Magnus, DA}, title = {Complex Control of a Genomic Island Governing Biofilm and Rugose Colony Development in Vibrio vulnificus.}, journal = {Journal of bacteriology}, volume = {200}, number = {16}, pages = {}, pmid = {29760209}, issn = {1098-5530}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Gene Transfer, Horizontal ; Genome, Bacterial ; *Genomic Islands ; Operon ; Phenotype ; Promoter Regions, Genetic ; Signal Transduction ; Vibrio vulnificus/*genetics/*physiology ; }, abstract = {Vibrio vulnificus is a potent opportunistic human pathogen that contaminates the human food chain by asymptomatically colonizing seafood. The expression of the 9-gene brp exopolysaccharide locus mediates surface adherence and is controlled by the secondary signaling molecule c-di-GMP and the regulator BrpT. Here, we show that c-di-GMP and BrpT also regulate the expression of an adjacent 5-gene cluster that includes the cabABC operon, brpT, and another VpsT-like transcriptional regulator gene, brpS The expression of the 14 genes spanning the region increased with elevated intracellular c-di-GMP levels in a BrpT-dependent manner, save for brpS, which was positively regulated by c-di-GMP and repressed by BrpT. BrpS repressed brpA expression and was required for rugose colony development. The mutation of its consensus WFSA c-di-GMP binding motif blocked these activities, suggesting that BrpS function is dependent on binding c-di-GMP. BrpT specifically bound the cabA, brpT, and brpS promoters, and binding sites homologous to the Vibrio cholerae VpsT binding site were identified upstream of brpA and brpT Transcription was initiated distal to brpA, and a conserved RfaH-recruiting ops element and a potential Rho utilization (rut) terminator site were identified within the 100-bp leader region, suggesting the integration of early termination and operon polarity suppression into the regulation of brp transcription. The GC content and codon usage of the 16-kb brp region was 5.5% lower relative to that of the flanking DNA, suggesting its recent assimilation via horizontal transfer. Thus, architecturally, the brp region can be considered an acquired biofilm and rugosity island that is subject to complex regulation.IMPORTANCE Biofilm and rugose colony formation are developmental programs that underpin the evolution of Vibrio vulnificus as a potent opportunistic human pathogen and successful environmental organism. A better understanding of the regulatory pathways governing theses phenotypes promotes the development and implementation of strategies to mitigate food chain contamination by this pathogen. c-di-GMP signaling is central to both pathways. We show that the molecule orchestrates the expression of 14 genes clustered in a 16-kb segment of the genome that governs biofilm and rugose colony development. This region exhibits the hallmarks of horizontal transfer, suggesting complex regulatory control of a recently assimilated genetic island governing the colonization response of V. vulnificus.}, } @article {pmid29760140, year = {2018}, author = {Ahmed, MN and Porse, A and Sommer, MOA and Høiby, N and Ciofu, O}, title = {Evolution of Antibiotic Resistance in Biofilm and Planktonic Pseudomonas aeruginosa Populations Exposed to Subinhibitory Levels of Ciprofloxacin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {8}, pages = {}, pmid = {29760140}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/*pharmacology ; Directed Molecular Evolution/methods ; Drug Resistance, Microbial ; Fimbriae, Bacterial/drug effects/genetics/metabolism ; *Genome, Bacterial ; Genotype ; Microbial Sensitivity Tests ; Phenotype ; Plankton/drug effects/*genetics/growth & development/pathogenicity ; Pseudomonas aeruginosa/drug effects/*genetics/growth & development/pathogenicity ; Virulence ; Whole Genome Sequencing ; }, abstract = {The opportunistic Gram-negative pathogen Pseudomonas aeruginosa, known for its intrinsic and acquired antibiotic resistance, has a notorious ability to form biofilms, which often facilitate chronic infections. The evolutionary paths to antibiotic resistance have mainly been investigated in planktonic cultures and are less studied in biofilms. We experimentally evolved P. aeruginosa PAO1 colony biofilms and stationary-phase planktonic cultures for seven passages in the presence of subinhibitory levels (0.1 mg/liter) of ciprofloxacin (CIP) and performed a genotypic (whole-bacterial population sequencing) and phenotypic assessment of the populations. We observed a higher proportion of CIP resistance in the CIP-evolved biofilm populations than in planktonic populations exposed to the same drug concentrations. However, the MICs of ciprofloxacin were lower in CIP-resistant isolates selected from the biofilm population than the MICs of CIP-resistant isolates from the planktonic cultures. We found common evolutionary trajectories between the different lineages, with mutations in known CIP resistance determinants as well as growth condition-dependent adaptations. We observed a general trend toward a reduction in type IV-pilus-dependent motility (twitching) in CIP-evolved populations and a loss of virulence-associated traits in the populations evolved in the absence of antibiotic. In conclusion, our data indicate that biofilms facilitate the development of low-level mutational resistance, probably due to the lower effective drug exposure than in planktonic cultures. These results provide a framework for the selection process of resistant variants and the evolutionary mechanisms involved under the two different growth conditions.}, } @article {pmid29758915, year = {2018}, author = {Zhang, L and Zhang, S and Lv, X and Qiu, Z and Zhang, Z and Yan, L}, title = {Dissolved organic matter release in overlying water and bacterial community shifts in biofilm during the decomposition of Myriophyllum verticillatum.}, journal = {The Science of the total environment}, volume = {633}, number = {}, pages = {929-937}, doi = {10.1016/j.scitotenv.2018.03.275}, pmid = {29758915}, issn = {1879-1026}, mesh = {Biofilms/classification/*growth & development ; Biomass ; Carbon/analysis ; Humic Substances ; Nitrogen/analysis ; Oxygen/analysis ; RNA, Ribosomal, 16S ; Tracheophyta/*metabolism/microbiology ; }, abstract = {This study investigated the alterations in biomass, nutrients and dissolved organic matter concentration in overlying water and determined the bacterial 16S rRNA gene in biofilms attached to plant residual during the decomposition of Myriophyllum verticillatum. The 55-day decomposition experimental results show that plant decay process can be well described by the exponential model, with the average decomposition rate of 0.037d[-1]. Total organic carbon, total nitrogen, and organic nitrogen concentrations increased significantly in overlying water during decomposition compared to control within 35d. Results from excitation emission matrix-parallel factor analysis showed humic acid-like and tyrosine acid-like substances might originate from plant degradation processes. Tyrosine acid-like substances had an obvious correlation to organic nitrogen and total nitrogen (p<0.01). Decomposition rates were positively related to pH, total organic carbon, oxidation-reduction potential and dissolved oxygen but negatively related to temperature in overlying water. Microbe densities attached to plant residues increased with decomposition process. The most dominant phylum was Bacteroidetes (>46%) at 7d, Chlorobi (20%-44%) or Proteobacteria (25%-34%) at 21d and Chlorobi (>40%) at 55d. In microbes attached to plant residues, sugar- and polysaccharides-degrading genus including Bacteroides, Blvii28, Fibrobacter, and Treponema dominated at 7d while Chlorobaculum, Rhodobacter, Methanobacterium, Thiobaca, Methanospirillum and Methanosarcina at 21d and 55d. These results gain the insight into the dissolved organic matter release and bacterial community shifts during submerged macrophytes decomposition.}, } @article {pmid29758533, year = {2018}, author = {Pereira, MF and Rossi, CC and Seide, LE and Martins Filho, S and Dolinski, CM and Bazzolli, DMS}, title = {Antimicrobial resistance, biofilm formation and virulence reveal Actinobacillus pleuropneumoniae strains' pathogenicity complexity.}, journal = {Research in veterinary science}, volume = {118}, number = {}, pages = {498-501}, doi = {10.1016/j.rvsc.2018.05.003}, pmid = {29758533}, issn = {1532-2661}, mesh = {Actinobacillus Infections/drug therapy/*microbiology ; Actinobacillus pleuropneumoniae/*drug effects/*physiology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; *Drug Resistance, Bacterial ; Swine ; Swine Diseases/drug therapy/*microbiology ; Virulence ; }, abstract = {Porcine pleuropneumonia is an important cause of lowered productivity and economic loss in the pig industry worldwide, associated primarily with Actinobacillus pleuropneumoniae infection. Its colonization and persistence within the upper respiratory tract of affected pigs depends upon interactions between a number of genetically controlled virulence factors, such as pore-forming repeats-in-toxin exoproteins, biofilm formation, and antimicrobial resistance. This study investigated correlations between biofilm-forming capacity, antimicrobial resistance, and virulence of A. pleuropneumoniae obtained from clinical outbreaks of disease, using a Galleria mellonella alternative infection model. Results suggest that virulence is diverse amongst the 21 strains of A. pleuropneumoniae examined and biofilm formation correlated with genetic control of antimicrobial resistance.}, } @article {pmid29758033, year = {2018}, author = {Pompilio, A and Crocetta, V and Savini, V and Petrelli, D and Di Nicola, M and Bucco, S and Amoroso, L and Bonomini, M and Di Bonaventura, G}, title = {Phylogenetic relationships, biofilm formation, motility, antibiotic resistance and extended virulence genotypes among Escherichia coli strains from women with community-onset primitive acute pyelonephritis.}, journal = {PloS one}, volume = {13}, number = {5}, pages = {e0196260}, pmid = {29758033}, issn = {1932-6203}, mesh = {Adolescent ; Adult ; Biofilms/growth & development ; Community-Acquired Infections/microbiology ; Drug Resistance, Microbial ; Escherichia coli/genetics/*pathogenicity/physiology ; Escherichia coli Infections/*microbiology ; Female ; Genes, Bacterial ; Genotype ; Humans ; Middle Aged ; Phylogeny ; Prospective Studies ; Pyelonephritis/*microbiology ; Virulence/genetics ; Young Adult ; }, abstract = {The present work set out to search for a virulence repertoire distinctive for Escherichia coli causing primitive acute pyelonephritis (APN). To this end, the virulence potential of 18 E. coli APN strains was genotypically and phenotypically assessed, comparatively with 19 strains causing recurrent cystitis (RC), and 16 clinically not significant (control, CO) strains. Most of the strains belong to phylogenetic group B1 (69.8%; p<0.01), and APN strains showed unique features, which are the presence of phylogroup A, and the absence of phylogroup B2 and non-typeable strains. Overall, the most dominant virulence factor genes (VFGs) were ecpA and fyuA (92.4 and 86.7%, respectively; p<0.05), and the mean number of VFGs was significantly higher in uropathogenic strains. Particularly, papAH and malX were exclusive for uropathogenic strains. APN and RC strains showed a significantly higher prevalence of fyuA, usp, and malX than of CO strains. Compared to RC strains, APN ones showed a higher prevalence of iha, but a lower prevalence of iroN, cnf1, and kpsMT-II. Hierarchical cluster analysis showed a higher proportion of two gene clusters (malX and usp, and fyuA and ecpA) were detected in the APN and RC groups than in CO, whereas iutA and iha clusters were detected more frequently in APN strains. The motility level did not differ among the study-groups and phylogroups considered, although a higher proportion of swarming strains was observed in APN strains. Antibiotic-resistance rates were generally low except for ampicillin (37.7%), and were not associated with specific study- or phylogenetic groups. APN and RC strains produced more biofilm than CO strains. In APN strains, iha was associated with higher biofilm biomass formation, whereas iroN and KpSMT-K1 were associated with a lower amount of biofilm biomass. Further work is needed to grasp the virulence and fitness mechanisms adopted by E. coli causing APN, and hence develop new therapeutic and prophylactic approaches.}, } @article {pmid29753132, year = {2018}, author = {Lin, Q and Deslouches, B and Montelaro, RC and Di, YP}, title = {Prevention of ESKAPE pathogen biofilm formation by antimicrobial peptides WLBU2 and LL37.}, journal = {International journal of antimicrobial agents}, volume = {52}, number = {5}, pages = {667-672}, pmid = {29753132}, issn = {1872-7913}, support = {R01 AI133351/AI/NIAID NIH HHS/United States ; R01 HL125128/HL/NHLBI NIH HHS/United States ; }, mesh = {Adult ; Anti-Infective Agents/*metabolism ; Antimicrobial Cationic Peptides/*metabolism ; Bacterial Infections/microbiology ; Biofilms/*drug effects/growth & development ; Child ; Child, Preschool ; Gene Expression Profiling ; Gentian Violet/analysis ; Gram-Negative Bacteria/*drug effects/genetics/growth & development/isolation & purification ; Gram-Positive Bacteria/*drug effects/genetics/growth & development/isolation & purification ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Staining and Labeling ; Young Adult ; Cathelicidins ; }, abstract = {OBJECTIVES: Bacterial biofilm-dependent infections (e.g. cystic fibrosis, surgical sites, and medical implants) are associated with enhanced drug-resistance and are thus difficult to eradicate. The goal of this study was to systematically compare three distinct classes of antimicrobial peptides (AMPs) that include the clinically used antibiotic colistin, the natural AMP LL37, the engineered cationic-AMP WLBU2, and four commonly used antibiotics with different bactericidal mechanisms (tobramycin, ciprofloxacin, ceftazidime, and vancomycin) for biofilm prevention properties.

METHODS: Using biofilm-prevention assays, we detected bacterial biomass post-attachment in subinhibitory concentrations (1/3 of the minimum inhibitory concentration [MIC]) for each AMP by the crystal violet method, to distinguish the commonly known bactericidal activity from potentially distinct mechanisms of biofilm prevention. Biofilm regulatory gene expression was assessed using RT-qPCR for correlation with biofilm growth inhibition.

RESULTS: Commonly used antibiotics at 1x MIC showed modest ESKAPE biofilm prevention while 1/3 MIC of AMPs demonstrated up to 90% biofilm prevention. WLBU2 was generally more effective in preventing bacterial attachment than colistin and LL37. Changes in bacterial biofilm regulatory gene expression were consistent with biofilm prevention.

CONCLUSION: The data warrant further exploration of AMPs with optimized structures to fill a knowledge gap on the potential application of AMPs for difficult-to-cure bacterial biofilm-related infections.}, } @article {pmid29752494, year = {2018}, author = {Zhang, X and Ma, Y and Ye, G}, title = {Morphological Observation and Comparative Transcriptomic Analysis of Clostridium perfringens Biofilm and Planktonic Cells.}, journal = {Current microbiology}, volume = {75}, number = {9}, pages = {1182-1189}, pmid = {29752494}, issn = {1432-0991}, support = {31460672, 31760739//National Natural Science Foundation Programs of China/ ; }, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Biosynthetic Pathways ; Clostridium perfringens/*cytology/*genetics/growth & development/ultrastructure ; Extracellular Polymeric Substance Matrix/cytology/genetics/ultrastructure ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Molecular Sequence Annotation ; Plankton/microbiology ; Sequence Analysis, DNA ; }, abstract = {Bacterial biofilms can enhance survival in adverse environments and promote infection. However, little is known about biofilm formation by Clostridium perfringens. To better characterize this process, we used SEM to observe the surfaces of C. perfringens biofilms after 12, 24, 48, and 72 h of incubation. Biofilm cells appeared to be encased in a dense matrix material, and the total biomass of the biofilm increased with incubation time. To gain insight into the differentially expressed genes (DEGs) between biofilm and planktonic cells, we carried out comparative transcriptomic analysis using RNA sequencing. In total, 91 genes were significantly differentially expressed, with 40 being up-regulated and 51 down-regulated. In particular, genes encoding sortase, ribosomal proteins, and ATP synthase were up-regulated in biofilms, while genes coding for clostripain and phospholipase C were down-regulated. To validate the RNA sequencing results, qRT-PCR analysis was performed using five randomly selected DEGs. Results showed that all five genes were up-regulated, which was in accordance with the RNA sequencing results. To examine the functional differences, the DEGs were characterized by GO and KEGG pathway enrichment analyses. Results showed that the up-regulated genes were divided into 32 significantly enriched GO terms, with "macromolecular complex" being the most common. Oxidative phosphorylation was the only significantly enriched pathway, suggesting that ATP is required for biofilm stability. This study provides valuable insights into the morphology and transcriptional regulation of C. perfringens during biofilm formation, and will be useful for understanding and developing biofilm-based processes.}, } @article {pmid29752266, year = {2018}, author = {Windham, IH and Servetas, SL and Whitmire, JM and Pletzer, D and Hancock, REW and Merrell, DS}, title = {Helicobacter pylori Biofilm Formation Is Differentially Affected by Common Culture Conditions, and Proteins Play a Central Role in the Biofilm Matrix.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {14}, pages = {}, pmid = {29752266}, issn = {1098-5336}, support = {R21 AI121517/AI/NIAID NIH HHS/United States ; FDN-154287//CIHR/Canada ; }, mesh = {Biofilms/*growth & development ; Culture Media ; DNA, Bacterial/genetics/*isolation & purification ; Extracellular Polymeric Substance Matrix/*metabolism ; Helicobacter pylori/*growth & development/*isolation & purification ; Microscopy, Confocal ; }, abstract = {The concept of Helicobacter pylori biofilm formation is relatively new. To help provide a foundation for future biofilm studies, we characterized the biofilm formation ability of a common H. pylori lab strain, G27. The goal of this study was to evaluate biofilm formation by G27 in response to common culture conditions and to explore the biofilm matrix. Our results indicate that while various types of growth media did not dramatically affect biofilm formation, surface selection had a significant effect on the final biofilm mass. Furthermore, enzymatic assays and confocal microscopy revealed that proteins appear to be the primary structural component of the H. pylori extracellular matrix; extracellular DNA (eDNA) and polysaccharides were also present but appear to play a secondary role. Finally, we found that two well-characterized antibiofilm cationic peptides differentially affected early and late-stage biofilms. Together these results provide interesting avenues for future investigations that will seek to understand H. pylori biofilm formation.IMPORTANCE The study of H. pylori biofilm formation is still in its infancy. As such, there is great variability in how biofilm assays are performed across labs. While several groups have begun to investigate factors that influence H. pylori biofilm formation, it is not yet understood how H. pylori biofilm formation may vary based on commonly used conditions. These inconsistencies lead to difficulties in interpretation and comparison between studies. Here, we set out to characterize biofilm formation by a commonly available lab strain, G27. Our findings provide novel insight into optimal biofilm conditions, the biofilm matrix, and possible mechanisms to block or disrupt biofilm formation.}, } @article {pmid29751426, year = {2018}, author = {Pfendler, S and Karimi, B and Maron, PA and Ciadamidaro, L and Valot, B and Bousta, F and Alaoui-Sosse, L and Alaoui-Sosse, B and Aleya, L}, title = {Biofilm biodiversity in French and Swiss show caves using the metabarcoding approach: First data.}, journal = {The Science of the total environment}, volume = {615}, number = {}, pages = {1207-1217}, doi = {10.1016/j.scitotenv.2017.10.054}, pmid = {29751426}, issn = {1879-1026}, mesh = {Ascomycota ; *Biodiversity ; Biofilms/*classification ; Caves/*microbiology ; Chlorophyta ; Cyanobacteria ; Diatoms ; *Environmental Pollutants ; France ; Microalgae ; Paintings ; Switzerland ; }, abstract = {In recent decades, show caves have begun to suffer from microorganism proliferation due to artificial lighting installations for touristic activity. In addition to the aesthetic problem, light encourages microorganisms that are responsible for physical and chemical degradation of limestone walls, speleothems and prehistoric paintings of cultural value. Microorganisms have previously been described by microscopy or culture-dependent methods, but data provided by new generation sequencing are rare. The authors identified, for the first time, microorganisms proliferating in one Swiss and in four French show caves using three different primers. The results showed that both photosynthetic and non-photosynthetic bacteria were the dominant taxa present in biofilms. Microalgae were heavily represented by the Trebouxiophyceae, Eustigmatophyceae and Chlorophyceae groups. Twelve diatoms were also recorded, with dominance of Syntrichia sp. (96.1%). Fungi were predominantly represented by Ascomycota, Zygomycota and Basidiomycota, fully half of the sampled biofilms where Fungi were detected. Comparing microbial communities from bleach-treated caves to those in untreated caves showed no significant difference except for a low-level change in the abundance of certain taxa. These findings provided by Illumina sequencing reveal a complex community structure in the 5 caves based on the assembly of bacteria, cyanobacteria, algae, diatoms, fungi and mosses.}, } @article {pmid29751310, year = {2018}, author = {Li, H and Song, HL and Yang, XL and Zhang, S and Yang, YL and Zhang, LM and Xu, H and Wang, YW}, title = {A continuous flow MFC-CW coupled with a biofilm electrode reactor to simultaneously attenuate sulfamethoxazole and its corresponding resistance genes.}, journal = {The Science of the total environment}, volume = {637-638}, number = {}, pages = {295-305}, doi = {10.1016/j.scitotenv.2018.04.359}, pmid = {29751310}, issn = {1879-1026}, mesh = {Bioelectric Energy Sources ; *Biofilms ; *Electrodes ; RNA, Ribosomal, 16S ; Sulfamethoxazole ; Waste Disposal, Fluid/*methods ; *Wastewater ; }, abstract = {A continuous flow microbial fuel cell constructed wetland (MFC-CW) coupled with a biofilm electrode reactor (BER) system was constructed to remove sulfamethoxazole (SMX). The BER unit powered by the stacked MFC-CWs was used as a pretreatment unit, and effluent flowed into the MFC-CW for further degradation. The experimental results indicated that the removal rate of 2 or 4 mg/L SMX in a BER unit was nearly 90%, and the total removal rate in the coupled system was over 99%. As the hydraulic retention time (HRT) was reduced from 16 h to 4 h, the SMX removal rate in the BER decreased from 75% to 48%. However, the total removal rate in the coupled system was still over 97%. The maximum SMX removal rate in the MFC-CW, which accounted for 42%-55% of the total removal, was obtained in the anode layer. In addition, the relative abundances of sul genes detected in the systems were in the order of sulI > sulII > sulIII, and significant positive correlations of sul gene copy numbers versus SMX concentration and 16S rRNA gene copy numbers were observed. Furthermore, significant negative correlations were identified between sul genes, 16S rRNA gene copy numbers, and HRT. The abundances of the sul genes in the effluent of the MFC-CW were lower than the abundances observed in the BER effluent. High-throughput sequencing revealed that the microbial community diversity of the BER was affected by running time, power supply forms and HRT. Bio-electricity from the MFC-CW may reduce microbial community diversity and contribute to reduction of the antibiotic resistance gene (ARG) abundance in the BER. Taken together, the BER-MFC-CW coupled system is a potential tool to treat wastewater containing SMX and attenuate corresponding ARG abundance.}, } @article {pmid29751065, year = {2018}, author = {Zhao, X and Liu, R and Tang, H and Osei-Adjei, G and Xu, S and Zhang, Y and Huang, X}, title = {A 3' UTR-derived non-coding RNA RibS increases expression of cfa and promotes biofilm formation of Salmonella enterica serovar Typhi.}, journal = {Research in microbiology}, volume = {169}, number = {6}, pages = {279-288}, doi = {10.1016/j.resmic.2018.04.007}, pmid = {29751065}, issn = {1769-7123}, mesh = {3' Untranslated Regions/*genetics ; Base Sequence ; Biofilms/*growth & development ; Gene Deletion ; Gene Knockout Techniques ; Methyltransferases/*genetics ; RNA, Untranslated/*genetics ; Riboflavin Synthase/*genetics ; Salmonella typhi/*genetics/metabolism/pathogenicity ; }, abstract = {Bacterial non-coding RNAs (ncRNAs) are widely studied and found to play important roles in regulating various cellular processes. Recently, many ncRNAs have been discovered to be transcribed or processed from 3' untranslated regions (3' UTRs). Here we reported a novel 3' UTR-derived ncRNA, RibS, which could influence biofilm formation of Salmonella enterica serovar Typhi (S. Typhi). RibS was confirmed to be a ∼700 nt processed product produced by RNase III-catalyzed cleavage from the 3' UTR of riboflavin synthase subunit alpha mRNA, RibE. Overexpression of RibS increased the expression of the cyclopropane fatty acid synthase gene, cfa, which was located at the antisense strand. Biofilm formation of S. Typhi was enhanced by overexpressing RibS both in the wild type strain and cfa deletion mutant. Deletion of cfa attenuated biofilm formation of S. Typhi, while complementation of cfa partly restored the phenotype. Moreover, overexpressing cfa enhanced the biofilm formation of S. Typhi. In summary, RibS has been identified as a novel ncRNA derived from the 3' UTR of RibE that promotes biofilm formation of S. Typhi, and it appears to do so, at least in part, by increasing the expression of cfa.}, } @article {pmid29748514, year = {2018}, author = {Salta, M and Dennington, SP and Wharton, JA}, title = {Biofilm Inhibition by Novel Natural Product- and Biocide-Containing Coatings Using High-Throughput Screening.}, journal = {International journal of molecular sciences}, volume = {19}, number = {5}, pages = {}, pmid = {29748514}, issn = {1422-0067}, mesh = {Bacteria/*drug effects/ultrastructure ; Biofilms/*drug effects ; Biological Products/*chemistry ; Diatoms/*drug effects/ultrastructure ; Disinfectants/chemistry ; High-Throughput Screening Assays ; Microscopy, Confocal ; }, abstract = {The use of natural products (NPs) as possible alternative biocidal compounds for use in antifouling coatings has been the focus of research over the past decades. Despite the importance of this field, the efficacy of a given NP against biofilm (mainly bacteria and diatoms) formation is tested with the NP being in solution, while almost no studies test the effect of an NP once incorporated into a coating system. The development of a novel bioassay to assess the activity of NP-containing and biocide-containing coatings against marine biofilm formation has been achieved using a high-throughput microplate reader and highly sensitive confocal laser scanning microscopy (CLSM), as well as nucleic acid staining. Juglone, an isolated NP that has previously shown efficacy against bacterial attachment, was incorporated into a simple coating matrix. Biofilm formation over 48 h was assessed and compared against coatings containing the NP and the commonly used booster biocide, cuprous oxide. Leaching of the NP from the coating was quantified at two time points, 24 h and 48 h, showing evidence of both juglone and cuprous oxide being released. Results from the microplate reader showed that the NP coatings exhibited antifouling efficacy, significantly inhibiting biofilm formation when compared to the control coatings, while NP coatings and the cuprous oxide coatings performed equally well. CLSM results and COMSTAT analysis on biofilm 3D morphology showed comparable results when the NP coatings were tested against the controls, with higher biofilm biovolume and maximum thickness being found on the controls. This new method proved to be repeatable and insightful and we believe it is applicable in antifouling and other numerous applications where interactions between biofilm formation and surfaces is of interest.}, } @article {pmid29745769, year = {2018}, author = {Winfield, MO and Downer, A and Longyear, J and Dale, M and Barker, GLA}, title = {Comparative study of biofilm formation on biocidal antifouling and fouling-release coatings using next-generation DNA sequencing.}, journal = {Biofouling}, volume = {34}, number = {4}, pages = {464-477}, doi = {10.1080/08927014.2018.1464152}, pmid = {29745769}, issn = {1029-2454}, mesh = {Bacteria/*isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; *Biofouling ; Eukaryota/*isolation & purification/physiology ; High-Throughput Nucleotide Sequencing ; Sequence Analysis, DNA ; }, abstract = {The bacterial and eukaryotic communities forming biofilms on six different antifouling coatings, three biocidal and three fouling-release, on boards statically submerged in a marine environment were studied using next-generation sequencing. Sequenced amplicons of bacterial 16S ribosomal DNA and eukaryotic ribosomal DNA internal transcribed spacer were assigned taxonomy by comparison to reference databases and relative abundances were calculated. Differences in species composition, bacterial and eukaryotic, and relative abundance were observed between the biofilms on the various coatings; the main difference was between coating type, biocidal compared to fouling-release. Species composition and relative abundance also changed through time. Thus, it was possible to group replicate samples by coating and time point, indicating that there are fundamental and reproducible differences in biofilms assemblages. The routine use of next-generation sequencing to assess biofilm formation will allow evaluation of the efficacy of various commercial coatings and the identification of targets for novel formulations.}, } @article {pmid29745728, year = {2018}, author = {Pattnaik, S and Ahmed, T and Ranganathan, SK and Ampasala, DR and Sarma, VV and Busi, S}, title = {Aspergillus ochraceopetaliformis SSP13 modulates quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1.}, journal = {Biofouling}, volume = {34}, number = {4}, pages = {410-425}, doi = {10.1080/08927014.2018.1460748}, pmid = {29745728}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Aspergillus/*chemistry ; Bacterial Proteins/genetics ; Biofilms/growth & development ; Chitinases/genetics ; Gene Expression Regulation, Bacterial ; Glycolipids ; Molecular Docking Simulation ; Peptide Hydrolases/genetics ; Pseudomonas aeruginosa/*drug effects/metabolism/physiology ; Pyocyanine/genetics ; Quorum Sensing/*drug effects ; *Virulence ; }, abstract = {Pseudomonas aeruginosa is an opportunistic nosocomial pathogen causing the majority of acute and persistent infections in human beings. The ability to form biofilm adds a new dimension to its resistance to conventional therapeutic agents. In the present study, down-regulation of quorum sensing regulated virulence and biofilm development resulting from exposure to Aspergillus ochraceopetaliformis SSP13 extract was investigated. The in vitro results inferred impairment in the production of LasA protease, LasB elastase, chitinase, pyocyanin, exopolysaccharides and rhamnolipids. In addition, motility and biofilm formation by P. aeruginosa PAO1 was significantly altered. The in vitro results were further supported by molecular docking studies of the metabolites obtained from GC-MS analysis depicting the quorum sensing attenuation by targeting the receptor proteins LasR and RhlR. The in vitro and in silico studies suggested new avenues for the development of bioactive metabolites from A. ochraceopetaliformis SSP13 extract as potential anti-infective agents.}, } @article {pmid29744925, year = {2018}, author = {Ravn, C and Ferreira, IS and Maiolo, E and Overgaard, S and Trampuz, A}, title = {Microcalorimetric detection of staphylococcal biofilm growth on various prosthetic biomaterials after exposure to daptomycin.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {36}, number = {10}, pages = {2809-2816}, doi = {10.1002/jor.24040}, pmid = {29744925}, issn = {1554-527X}, support = {//The Danish Rheumatism Association/International ; //Regional Foundation of Southern Denmark/International ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Calorimetry ; Daptomycin/*pharmacology ; Drug Evaluation, Preclinical ; Prostheses and Implants/*microbiology ; Staphylococcus/*drug effects ; }, abstract = {Primary aim of this in vitro study was to test the efficacy of daptomycin to eradicate staphylococcal biofilms on various orthopedic implant materials. Secondary aim was to quantitatively estimate the formation of staphylococcal biofilm. We tested six clinically important biomaterials: Cobalt chrome, pure titanium, grid-blasted titanium, porous plasma-coated titanium with/without hydroxyapatite, and polyethylene. Biofilms of S. aureus and S. epidermidis were formed on the samples and thereafter exposed to daptomycin. Samples were subsequently sonicated in order to detect dislodged biofilm bacteria and transferred to a microcalorimeter for real-time measurement of growth-related heat flow. Minimal biofilm eradication concentration (MBEC) was determined as the lowest concentration of daptomycin required to eradicate biofilm bacteria on the sample. Median MBEC of S. aureus biofilm on smooth metallic surfaces was lower than the rough metallic surfaces. In experiments with S. epidermidis, no pattern was seen in relation to the surface roughness. Regarding the quantitative estimation of staphylococcal biofilm formation on the sample, we found a significantly higher amount of biofilm growth on the rough surfaces than the smooth samples and polyethylene. In conclusion, the presented study showed that daptomycin could eradicate S. aureus biofilm at lower concentrations on the smooth surfaces compared to the rough surfaces, as well as polyethylene. In experiments with daptomycin against S. epidermidis biofilms, no pattern was seen in relation to the surface roughness. Furthermore, we demonstrated a faster detection of staphylococcal heat flow due to higher biofilm quantity on the rough surfaces compared to smooth samples and polyethylene. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2809-2816, 2018.}, } @article {pmid29744476, year = {2018}, author = {Cai, T and Tessarolo, F and Caola, I and Piccoli, F and Nollo, G and Caciagli, P and Mazzoli, S and Palmieri, A and Verze, P and Malossini, G and Mirone, V and Bjerklund Johansen, TE}, title = {Prostate calcifications: A case series supporting the microbial biofilm theory.}, journal = {Investigative and clinical urology}, volume = {59}, number = {3}, pages = {187-193}, pmid = {29744476}, issn = {2466-054X}, mesh = {Aged ; Bacteriological Techniques ; *Biofilms ; Biopsy ; Calcinosis/diagnostic imaging/*microbiology/pathology ; Citrobacter freundii/isolation & purification ; Enterococcus faecalis/isolation & purification ; Humans ; Male ; Microscopy, Electrochemical, Scanning ; Middle Aged ; Prostate/pathology/ultrastructure ; Prostatectomy ; Prostatic Diseases/diagnostic imaging/*microbiology/pathology ; Ultrasonography ; }, abstract = {PURPOSE: Prostate calcifications are a common finding during transrectal prostate ultrasound in both healthy subjects and patients, but their etiopathogenesis and clinical significance are not fully understood. We aimed to establish a new methodology for evaluating the role of microbial biofilms in the genesis of prostate calcifications.

MATERIALS AND METHODS: Ten consecutive patients who had undergone radical prostatectomy were enrolled in this study. All of the patients presented with prostate calcifications during transrectal ultrasound evaluation before surgery and underwent Meares-Stamey tests and clinical evaluation with the National Institutes of Health Chronic Prostatitis Symptom Index and the International Prostate Symptom Score. At the time of radical prostatectomy, the prostate specimen, after removal, was analyzed with ultrasonography under sterile conditions in the operating room. Core biopsy specimens were taken from the site of prostate calcification and subjected to ultrastructural and microbiological analysis.

RESULTS: The results of the Meares-Stamey test showed only 1 of 10 patients (10%) with positive cultures for Escherichia coli. Two of five patients (40%) had positive cultures from prostate biopsy specimens. Enterococcus faecalis, Enterococcus raffinosus, and Citrobacter freundii were isolated. Ultrastructural analysis of the prostate biopsy specimens showed prostate calcifications in 6 of 10 patients (60%), and a structured microbial biofilm in 1 patient who had positive cultures for E. faecalis and E. raffinosus.

CONCLUSIONS: Although the findings are supported by a low number of patients, this study highlights the validity of the proposed methodology for investigating the role of bacterial biofilms in the genesis of prostate calcification.}, } @article {pmid29744214, year = {2018}, author = {Laosuwan, K and Epasinghe, DJ and Wu, Z and Leung, WK and Green, DW and Jung, HS}, title = {Comparison of biofilm formation and migration of Streptococcus mutans on tooth roots and titanium miniscrews.}, journal = {Clinical and experimental dental research}, volume = {4}, number = {2}, pages = {40-47}, pmid = {29744214}, issn = {2057-4347}, abstract = {Periodontitis and peri-implantitis are inflammatory diseases caused by periodontal pathogenic bacteria leading to destruction of supporting periodontal/peri-implant tissue. However, the progression of inflammatory process of these two diseases is different. The bacterial biofilm is the source of bacteria during the inflammatory process. As the bacteria migrate down the surface of tooth or titanium implant, the inflammation spreads along with it. Streptococcus mutans has an important role in oral bacterial biofilm formation in early stage biofilm before the microbiota shift to late stage and become more virulent. The other major difference is the existence of periodontal ligament (PDL) cells in normal teeth but not in peri-implant tissue. This study aims to compare the S. mutans bacterial biofilm formation and migration on 2 different surfaces, tooth root and titanium miniscrew. The biofilm was grown with a flow cells system to imitate the oral dynamic system with PDL cells. The migration distances were measured, and the biofilm morphology was observed. Data showed that the biofilm formation on miniscrew was slower than those on tooth root at 24 hr. However, there were no difference in the morphology of the biofilm formed on the tooth root with those formed on the miniscrew at both 24 and 48 hr. The biofilm migration rate was significantly faster on miniscrew surface compare with those on tooth root when observe at 48 hr (p < .001). There are no significant differences in biofilm migration within miniscrew group and tooth root group despite the exiting of PDL cell (p > .05). The biofilm's migration rate differences on various surfaces could be one of the factors accounting for the different inflammatory progression between periodontitis and peri-implantitis disease.}, } @article {pmid29744212, year = {2018}, author = {Tastepe, CS and Lin, X and Werner, A and Donnet, M and Wismeijer, D and Liu, Y}, title = {Cleaning effect of osteoconductive powder abrasive treatment on explanted human implants and biofilm-coated titanium discs.}, journal = {Clinical and experimental dental research}, volume = {4}, number = {1}, pages = {25-34}, pmid = {29744212}, issn = {2057-4347}, abstract = {The aim of this study is to test the cleaning effect and surface modification of a new implant surface treatment on explanted dental implants and titanium discs. It is a modified air powder abrasive (APA) treatment applied using osteoconductive powders. Twenty-eight in vitro Ca-precipitated organic film-coated titanium discs and 13 explanted dental implants were treated. In a 2-step approach, 3 powders were used: hydroxylapatite (HA) and biomimetic calcium phosphate (BioCaP), which are osteoconductive, and erythritol, which is not. APA treatment was applied. (Air pressure: 2.4 bar; water flow for cleaning: 41.5 ml/min, for Coating 1: 2.1 ml/min, and for Coating 2: 15.2 ml/min.) The test groups were as follows: Group 1: HA cleaning + BioCaP Coating 1; Group 2: HA cleaning + BioCaP Coating 2; Group 3: erythritol cleaning + BioCaP Coating 1; Group 4: erythritol cleaning + BioCaP Coating 2; Group 5: HA cleaning; Group 6: erythritol cleaning; and control: no powder. Cleaned areas were calculated by point counting method. Surface changes and chemical content were evaluated using light microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Cleaning effect between groups was compared by a pairwise Student's t test. The significance level was fixed at p < .05. Cleaning effect on the discs was 100% in all test groups and 5% in the control. Powder particles in varying size and shape were embedded on the surface. All HA- or CaP-treated surfaces showed Ca and P content but no surface damage. Calcified biofilm remnants were removed from the implant surface by the test groups, whereas in control groups, they remained. APA treatment with CaP and HA powders under clinically applicable pressure settings gives positive results in vitro; therefore, they could be promising when used in vivo.}, } @article {pmid29744209, year = {2018}, author = {Dabija-Wolter, G and Al-Zubaydi, SS and Mohammed, MMA and Bakken, V and Bolstad, AI}, title = {The effect of metronidazole plus amoxicillin or metronidazole plus penicillin V on periodontal pathogens in an in vitro biofilm model.}, journal = {Clinical and experimental dental research}, volume = {4}, number = {1}, pages = {6-12}, pmid = {29744209}, issn = {2057-4347}, abstract = {A combination of metronidazole (MET) and amoxicillin (AMX) is commonly used as adjunct to mechanical therapy of periodontal disease. The use of broad spectrum antibiotics such as AMX may contribute to development of antibiotic resistance. The aim was to evaluate the in vitro effect of replacing AMX with penicillin V (PV) in combination with MET on a biofilm model. A biofilm model consisting of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum was developed. The biofilms were exposed to AMX + MET and PV + MET in two different concentrations. Bacterial viability in biofilms following antibiotic exposure was assessed by viable counts and by confocal microscopy. No live colonies of P. gingivalis nor F. nucleatum were retrieved from biofilms exposed to AMX + MET or PV + MET. The amount of A. actinomycetemcomitans was 4-5 logs reduced following antibiotic treatment; no statistical significance was achieved between AMX + MET or PV + MET treated biofilms. Replacement of AMX with PV at the same concentration, in combination with MET, resulted in similar effect on bacterial viability in this in vitro model. The option of using PV + MET instead of AMX + MET deserves further investigation, as this may contribute to reduce the risk of antibiotic resistance development.}, } @article {pmid29743338, year = {2018}, author = {Hathroubi, S and Servetas, SL and Windham, I and Merrell, DS and Ottemann, KM}, title = {Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis.}, journal = {Microbiology and molecular biology reviews : MMBR}, volume = {82}, number = {2}, pages = {}, pmid = {29743338}, issn = {1098-5557}, support = {R01 AI116946/AI/NIAID NIH HHS/United States ; R21 AI121517/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/*therapeutic use ; Biofilms/drug effects/*growth & development ; Chronic Disease ; Disease Models, Animal ; Drug Resistance, Microbial/genetics ; Gastric Mucosa/*microbiology ; Helicobacter Infections/*drug therapy/*microbiology/pathology ; Helicobacter pylori/drug effects/genetics/*pathogenicity ; Humans ; Recurrence ; }, abstract = {Despite decades of effort, Helicobacter pylori infections remain difficult to treat. Over half of the world's population is infected by H. pylori, which is a major cause of duodenal and gastric ulcers as well as gastric cancer. During chronic infection, H. pylori localizes within the gastric mucosal layer, including deep within invaginations called glands; thanks to its impressive ability to survive despite the harsh acidic environment, it can persist for the host's lifetime. This ability to survive and persist in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation has recently been suggested to play a role in colonization. Biofilms are surface-associated communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances. Biofilms pose a substantial health risk and are key contributors to many chronic and recurrent infections. This link between biofilm-associated bacteria and chronic infections likely results from an increased tolerance to conventional antibiotic treatments as well as immune system action. The role of this biofilm mode in antimicrobial treatment failure and H. pylori survival has yet to be determined. Furthermore, relatively little is known about the H. pylori biofilm structure or the genes associated with this mode of growth. In this review, therefore, we aim to highlight recent findings concerning H. pylori biofilms and the molecular mechanism of their formation. Additionally, we discuss the potential roles of biofilms in the failure of antibiotic treatment and in infection recurrence.}, } @article {pmid29740541, year = {2018}, author = {Kaur, S and Sharma, P and Kalia, N and Singh, J and Kaur, S}, title = {Anti-biofilm Properties of the Fecal Probiotic Lactobacilli Against Vibrio spp.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {120}, pmid = {29740541}, issn = {2235-2988}, mesh = {Adolescent ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Cell Line ; Child ; Child, Preschool ; Cholera/microbiology/*prevention & control/*therapy ; Disk Diffusion Antimicrobial Tests ; Humans ; Lactobacillus/classification/isolation & purification/*metabolism ; Probiotics/*therapeutic use ; Vibrio cholerae/*growth & development ; Vibrio parahaemolyticus/*growth & development ; }, abstract = {Diarrheal disease caused by Vibrio cholerae is endemic in developing countries including India and is associated with high rate of mortality especially in children. V. cholerae is known to form biofilms on the gut epithelium, and the biofilms once formed are resistant to the action of antibiotics. Therefore agents that prevent the biofilm formation and disperse the preformed biofilms are associated with therapeutic benefits. The use of antibiotics for the treatment of cholera is associated with side effects such as gut dysbiosis due to depletion of gut microflora, and the increasing problem of antibiotic resistance. Thus search for safe alternative therapeutic agents is warranted. Herein, we screened the lactobacilli spp. isolated from the fecal samples of healthy children for their abilities to prevent biofilm formation and to disperse the preformed biofilms of V. cholerae and V. parahaemolyticus by using an in vitro assay. The results showed that the culture supernatant (CS) of all the seven isolates of Lactobacillus spp. used in the study inhibited the biofilm formation of V. cholerae by more than 90%. Neutralization of pH of CS completely abrogated their antimicrobial activities against V. cholera, but had negligible effects on their biofilm inhibitory potential. Further, CS of all the lactobacilli isolates caused the dispersion of preformed V. cholerae biofilms in the range 62-85%; however, pH neutralization of CS reduced the biofilm dispersal potential of the 4 out of 7 isolates by 19-57%. Furthermore, the studies showed that CS of none of the lactobacilii isolates had antimicrobial activity against V. parahaemolyticus, but 5 out of 7 isolates inhibited the formation of its biofilm in the range 62-82%. However, none of the CS dispersed the preformed biofilms of V. parahaemolyticus. The ability of CS to inhibit the adherence of Vibrio spp. to the epithelial cell line was also determined. Thus, we conclude that the biofilm dispersive action of CS of lactobacilli is strain-specific and pH-dependent. As Vibrio is known to form biofilms in the intestinal niche having physiological pH in the range 6-7, the probiotic strains that have dispersive action at high pH may have better therapeutic potential.}, } @article {pmid29740176, year = {2018}, author = {Wang, YC and Huang, TW and Yang, YS and Kuo, SC and Chen, CT and Liu, CP and Liu, YM and Chen, TL and Chang, FY and Wu, SH and How, CK and Lee, YT}, title = {Biofilm formation is not associated with worse outcome in Acinetobacter baumannii bacteraemic pneumonia.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {7289}, pmid = {29740176}, issn = {2045-2322}, mesh = {Acinetobacter Infections/*drug therapy/genetics/microbiology/pathology ; Acinetobacter baumannii/drug effects/genetics/pathogenicity ; Anti-Bacterial Agents/administration & dosage ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/administration & dosage ; Drug Resistance, Multiple, Bacterial ; Gene Expression Regulation/drug effects ; Humans ; Meropenem/administration & dosage ; Microbial Sensitivity Tests ; Pneumonia/*drug therapy/genetics/microbiology/pathology ; Retrospective Studies ; }, abstract = {The effect of biofilm formation on bacteraemic pneumonia caused by A. baumannii is unknown. We conducted a 4-year multi-center retrospective study to analyze 71 and 202 patients with A. baumannii bacteraemic pneumonia caused by biofilm-forming and non-biofilm-forming isolates, respectively. The clinical features and outcomes of patients were investigated. Biofilm formation was determined by a microtitre plate assay. The antimicrobial susceptibilities of biofilm-associated cells were assessed using the minimum biofilm eradication concentration (MBEC) assay. Whole-genome sequencing was conducted to identify biofilm-associated genes and their promoters. Quantitative reverse transcription polymerase chain reaction was performed to confirm the expression difference of biofilm-associated genes. There was no significant difference in the clinical characteristics or the outcomes between patients infected with biofilm-forming and non-biofilm-forming strains. Compared with non-biofilm-forming isolates, biofilm-forming isolates exhibited lower resistance to most antimicrobials tested, including imipenem, meropenem, ceftazidime, ciprofloxacin and gentamicin; however, the MBEC assay confirmed the increased antibiotic resistance of the biofilm-embedded bacteria. Biofilm-associated genes and their promoters were detected in most isolates, including the non-biofilm-forming strains. Biofilm-forming isolates showed higher levels of expression of the biofilm-associated genes than non-biofilm-forming isolates. The biofilm-forming ability of A. baumannii isolates might not be associated with worse outcomes in patients with bacteraemic pneumonia.}, } @article {pmid29739390, year = {2018}, author = {Gartika, M and Pramesti, HT and Kurnia, D and Satari, MH}, title = {A terpenoid isolated from sarang semut (Myrmecodia pendans) bulb and its potential for the inhibition and eradication of Streptococcus mutans biofilm.}, journal = {BMC complementary and alternative medicine}, volume = {18}, number = {1}, pages = {151}, pmid = {29739390}, issn = {1472-6882}, support = {872/UN6.3.1/LT/2017//Universitas Padjadjaran/ ; }, mesh = {Biofilms/*drug effects ; Dental Caries/microbiology ; Humans ; Magnetic Resonance Spectroscopy ; Plant Extracts/chemistry ; Rubiaceae/*chemistry ; Streptococcus mutans/*drug effects ; Terpenes/*isolation & purification/*pharmacology ; }, abstract = {BACKGROUND: Dental caries remains a serious problem due to its detrimental effects on individual health and quality of life. The bulbs of Myrmecodia pendans (Merr & Perry), native plants of Papua, have been used as natural remedies for tumours, gout, diarrhoea, and fever. In this study, one of the active compounds of M. pendans was isolated, and its biological activity against the formation of Streptococcus mutans ATCC 25175 biofilm was tested.

METHODS: M. pendans was extracted with ethyl acetate using a Soxhlet apparatus. The extract was then separated, and chromatographic purification provided the isolated compound. The structure of the active compound was then characterized using UV, IR, NMR, and MS spectrometry. The obtained compound was added to S. mutans biofilms to determine the MBIC and MBEC values.

RESULTS: The compound isolated from M. pendans was determined to be a labdane diterpene derivative with the formula C31H50O3. The MBIC value of the terpenoid towards the S. mutans biofilms was 50 ppm, and the MBEC value for the 1 min induction time was 40%.

CONCLUSION: The terpenoid extracted from M. pendans has the potential to be developed into an antibacterial agent particularly for preventing the formation of biofilms.}, } @article {pmid29739319, year = {2018}, author = {Lajhar, SA and Brownlie, J and Barlow, R}, title = {Characterization of biofilm-forming capacity and resistance to sanitizers of a range of E. coli O26 pathotypes from clinical cases and cattle in Australia.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {41}, pmid = {29739319}, issn = {1471-2180}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Disinfectants/pharmacology ; *Drug Resistance, Bacterial ; Enterohemorrhagic Escherichia coli/isolation & purification/virology ; Enteropathogenic Escherichia coli/isolation & purification/physiology/virology ; Escherichia coli Infections/*microbiology/veterinary ; Escherichia coli O157/isolation & purification/*physiology/virology ; Food Microbiology ; Humans ; Hydrophobic and Hydrophilic Interactions ; Prophages/genetics/isolation & purification ; }, abstract = {BACKGROUND: The formation of biofilms and subsequent encasement of bacterial cells in a complex matrix can enhance resistance to antimicrobials and sterilizing agents making these organisms difficult to eradicate and control. The aim of this study was to evaluate and compare the capacity of 40 E. coli O26 isolates of enterohemorrhagic E. coli (EHEC, n = 27), potential EHEC (pEHEC, n = 3), atypical enteropathogenic E. coli (aEPEC, n = 8) and non-toxigenic E. coli (NTEC, n = 2) from human and cattle sources to form biofilms on different surfaces, and determine whether extracellular matrix (ECM) components (cellulose, curli), motility, prophage insertion in mlrA and cell surface hydrophobicity could influence biofilm formation. Finally, the influence of biofilm formation on the sensitivity of isolates to quaternary ammonium compounds (QACs; Profoam, Kwiksan 22) and peracetic acid-based sanitizer (Topactive Des.) for 2 min on polystyrene plate were also evaluated.

RESULTS: Biofilm production on one surface may not indicate biofilm formation on a different surface. Biofilm was formed by different pathotypes on polystyrene (70%), stainless steel (87.5%) and glass slides (95%), however only 50% demonstrated pellicle formation. EHEC isolates were significantly more likely to form a pellicle at the air-liquid interface and biofilms on polystyrene surface at 48 h than aEPEC. Strains that don't produce ECM (curli or cellulose), harbor a prophage insertion in mlrA, and are non-motile have lower biofilm forming capacities than those isolates possessing combinations of these attributes. Hydrophobicity had no impact on biofilm formation. After 2 min exposure, none of the disinfectants tested were able to completely inactivate all cells within a biofilm regardless of pathotypes and the amount of biofilm formed.

CONCLUSION: Pathotypes of E. coli O26 showed varying capacities to form biofilms, however, most EHEC strains had the capacity to form biofilm on all surfaces and at the air-liquid interface under the conditions used in this study. Biofilms provided a protective effect to E. coli O26 strains against the three sanitizers, previously shown to successfully control the growth of their planktonic counterparts. Whether the characteristics of biofilm forming and non-biofilm forming strains observed in this study reflect their attributes within the food and meat-processing environments is unknown. Further studies that represent the food and meat-processing environments are required.}, } @article {pmid29738978, year = {2018}, author = {Song, T and Li, S and Ding, W and Li, H and Bao, M and Li, Y}, title = {Biodegradation of hydrolyzed polyacrylamide by the combined expanded granular sludge bed reactor-aerobic biofilm reactor biosystem and key microorganisms involved in this bioprocess.}, journal = {Bioresource technology}, volume = {263}, number = {}, pages = {153-162}, doi = {10.1016/j.biortech.2018.04.121}, pmid = {29738978}, issn = {1873-2976}, mesh = {*Acrylic Resins ; Biodegradation, Environmental ; Biofilms ; *Bioreactors ; Sewage ; }, abstract = {An investigation was carried out to study the performance of a combined expanded granular sludge bed reactor-aerobic biofilm reactor (EGSB-ABR) biosystem and key microorganisms involved in this bioprocess. When the concentration of hydrolyzed polyacrylamide (HPAM) was 500 mg/L, the maximum removal rate of HPAM reached 64.36%, among which the contribution of the EGSB reactor was 24.35%. Scanning electron microscope (SEM) images and gel permeation chromatography (GPC) analysis showed that macromolecular HPAM was degraded into oligomer with lower molecular weight. Among the key enzymes involved in the degradation of HPAM, laccase had the best tolerance to HPAM. Microbial community structure was analysed by Illumina MiSeq Sequencing, which revealed that Firmicutes, Proteobacteria and Bacteroidetes were the most prevalent bacterial phyla, Trichococcus, Brooklawnia, Bacillus and Pseudomonas were the predominant functional genera, and Methanosaeta was the dominant archaeal genus in the bioprocess. Furthermore, hypothesis about the mechanisms of HPAM biodegradation was proposed.}, } @article {pmid29738306, year = {2018}, author = {Svenningsen, NB and Martínez-García, E and Nicolaisen, MH and de Lorenzo, V and Nybroe, O}, title = {The biofilm matrix polysaccharides cellulose and alginate both protect Pseudomonas putida mt-2 against reactive oxygen species generated under matric stress and copper exposure.}, journal = {Microbiology (Reading, England)}, volume = {164}, number = {6}, pages = {883-888}, doi = {10.1099/mic.0.000667}, pmid = {29738306}, issn = {1465-2080}, mesh = {Adaptation, Physiological ; Alginates/*metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Cellulose/genetics/*metabolism ; Copper/*metabolism/toxicity ; Desiccation ; Extracellular Polymeric Substance Matrix/*chemistry/genetics ; Gene Deletion ; Gene Expression Regulation, Bacterial/drug effects ; Promoter Regions, Genetic ; Pseudomonas putida/genetics/growth & development/metabolism/*physiology ; Reactive Oxygen Species/*metabolism ; Stress, Physiological/drug effects/*physiology ; }, abstract = {In natural environments most bacteria live in biofilms embedded in complex matrices of extracellular polymeric substances (EPS). This lifestyle is known to increase protection against environmental stress. Pseudomonas putida mt-2 harbours genes for the production of at least four different EPS polysaccharides, including alginate and cellulose. Little is known about the functional properties of cellulose, while alginate attenuates the accumulation of reactive oxygen species (ROS) caused by matric stress. By using mutants that are deficient in either alginate or cellulose production we show that even cellulose attenuates the accumulation of matric stress-induced ROS for cells in biofilms. Further, both cellulose and alginate attenuate ROS generated through exposure to copper. Interestingly, the two EPS polysaccharides protect cells in both liquid culture and in biofilms against ROS caused by matric stress, indicating that cellulose and alginate do not need to be produced as an integral part of the biofilm lifestyle to provide tolerance towards environmental stressors.}, } @article {pmid29738295, year = {2018}, author = {Bowler, PG}, title = {Antibiotic resistance and biofilm tolerance: a combined threat in the treatment of chronic infections.}, journal = {Journal of wound care}, volume = {27}, number = {5}, pages = {273-277}, doi = {10.12968/jowc.2018.27.5.273}, pmid = {29738295}, issn = {0969-0700}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Chronic Disease/*drug therapy ; Drug Resistance, Microbial/*drug effects ; Humans ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {Since the introduction of antibiotics into human medicine in the 1940's, antibiotic resistance has emerged at an alarming rate and is now a major threat to public health. This problem is amplified by pathogenic bacteria existing most commonly in biofilm form, creating additional bacterial tolerance to antimicrobial agents. Biofilm is now considered to be a primary cause of chronic infection, and antibiotic-resistant bacteria are prevalent in biofilm form. In particular, chronic non-healing wounds commonly harbour complex polymicrobial, pathogenic biofilm that is tolerant to systemic and topical antimicrobial therapy. Antibiotic stewardship programmes have emerged globally to improve antibiotic prescribing practices, and to curb the emergence and spread of bacterial resistance. In this regard, new antimicrobial strategies must be considered, one of which is to use antibiofilm/antimicrobial combinations to disrupt biofilm, thereby facilitating effectiveness of antimicrobial agents, and reducing the opportunity for antibiotic resistance gene transfer within biofilm. This strategy is being considered in several clinical conditions, one of which is chronic non-healing wounds, where antibiotics are used excessively and often indiscriminately. A combination antibiofilm/antimicrobial wound dressing has been shown to facilitate healing in previously biofilm-impaired non-healing wounds. This approach must be considered as part of antibiotic stewardship programmes to reduce the usage and implications of antibiotic therapy, and improve outcomes associated with chronic infections.}, } @article {pmid29735842, year = {2018}, author = {Murugesan, S and Mani, S and Kuppusamy, I and Krishnan, P}, title = {Role of insertion sequence element is256 as a virulence marker and its association with biofilm formation among methicillin-resistant Staphylococcus epidermidis from hospital and community settings in Chennai, South India.}, journal = {Indian journal of medical microbiology}, volume = {36}, number = {1}, pages = {124-126}, doi = {10.4103/ijmm.IJMM_17_276}, pmid = {29735842}, issn = {1998-3646}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cross Infection/drug therapy/microbiology ; DNA Transposable Elements/*genetics ; Genes, Bacterial/genetics ; Humans ; India ; Methicillin/therapeutic use ; Methicillin Resistance/*genetics ; Polymerase Chain Reaction ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus epidermidis/*drug effects/*genetics/isolation & purification ; }, abstract = {The objective of this study was to detect the association of biofilm formation with IS256 among clinical and carrier isolates of methicillin-resistant Staphylococcus epidermidis (MRSE). A total of 71 MRSE isolates were included in this study. Phenotypic detection of biofilm formation was done by Congo red agar method. Detection of genes associated with biofilm formation (icaAD, aap and atlE) and insertion sequence IS256 was done by polymerase chain reaction. Of the 71 MRSE isolates,19/40 (47.5%) clinical isolates from hospital settings and 11/31 (35.5%) carrier isolates from community settings respectively were found to be positive for all the three genes tested, namely, icaAD[+], aap[+] and atlE[+] genes. Nearly 80% of clinical isolates were found to harbour IS256, whereas only 13% of community isolates harboured IS256.}, } @article {pmid29735756, year = {2018}, author = {Cheng, AT and Zamorano-Sánchez, D and Teschler, JK and Wu, D and Yildiz, FH}, title = {NtrC Adds a New Node to the Complex Regulatory Network of Biofilm Formation and vps Expression in Vibrio cholerae.}, journal = {Journal of bacteriology}, volume = {200}, number = {15}, pages = {}, pmid = {29735756}, issn = {1098-5530}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R01 AI114261/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression Regulation, Bacterial/*physiology ; Nitrogen/chemistry/metabolism ; Vibrio cholerae/*physiology ; }, abstract = {The biofilm growth mode is important in both the intestinal and environmental phases of the Vibrio cholerae life cycle. Regulation of biofilm formation involves several transcriptional regulators and alternative sigma factors. One such factor is the alternative sigma factor RpoN, which positively regulates biofilm formation. RpoN requires bacterial enhancer-binding proteins (bEBPs) to initiate transcription. The V. cholerae genome encodes seven bEBPs (LuxO, VC1522, VC1926 [DctD-1], FlrC, NtrC, VCA0142 [DctD-2], and PgtA) that belong to the NtrC family of response regulators (RRs) of two-component regulatory systems. The contribution of these regulators to biofilm formation is not well understood. In this study, we analyzed biofilm formation and the regulation of vpsL expression by RpoN activators. Mutants lacking NtrC had increased biofilm formation and vpsL expression. NtrC negatively regulates the expression of core regulators of biofilm formation (vpsR, vpsT, and hapR). NtrC from V. cholerae supported growth and activated glnA expression when nitrogen availability was limited. However, the repressive activity of NtrC toward vpsL expression was not affected by the nitrogen sources present. This study unveils the role of NtrC as a regulator of vps expression and biofilm formation in V. choleraeIMPORTANCE Biofilms play an important role in the Vibrio cholerae life cycle, contributing to both environmental survival and transmission to a human host. Identifying key regulators of V. cholerae biofilm formation is necessary to fully understand how this important growth mode is modulated in response to various signals encountered in the environment and the host. In this study, we characterized the role of RRs that function as coactivators of RpoN in regulating biofilm formation and identified new components in the V. cholerae biofilm regulatory circuitry.}, } @article {pmid29735695, year = {2018}, author = {Pakharukova, N and Tuittila, M and Paavilainen, S and Malmi, H and Parilova, O and Teneberg, S and Knight, SD and Zavialov, AV}, title = {Structural basis for Acinetobacter baumannii biofilm formation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {21}, pages = {5558-5563}, pmid = {29735695}, issn = {1091-6490}, mesh = {Acinetobacter baumannii/*chemistry/metabolism ; Adhesins, Bacterial/*chemistry/metabolism ; Amino Acid Sequence ; Bacterial Adhesion/*physiology ; Bacterial Proteins/*chemistry/metabolism ; Biofilms/*growth & development ; Crystallography, X-Ray ; Fimbriae, Bacterial/*chemistry/metabolism ; Molecular Chaperones/*chemistry/metabolism ; Phylogeny ; Sequence Homology ; }, abstract = {Acinetobacter baumannii-a leading cause of nosocomial infections-has a remarkable capacity to persist in hospital environments and medical devices due to its ability to form biofilms. Biofilm formation is mediated by Csu pili, assembled via the "archaic" chaperone-usher pathway. The X-ray structure of the CsuC-CsuE chaperone-adhesin preassembly complex reveals the basis for bacterial attachment to abiotic surfaces. CsuE exposes three hydrophobic finger-like loops at the tip of the pilus. Decreasing the hydrophobicity of these abolishes bacterial attachment, suggesting that archaic pili use tip-fingers to detect and bind to hydrophobic cavities in substrates. Antitip antibody completely blocks biofilm formation, presenting a means to prevent the spread of the pathogen. The use of hydrophilic materials instead of hydrophobic plastics in medical devices may represent another simple and cheap solution to reduce pathogen spread. Phylogenetic analysis suggests that the tip-fingers binding mechanism is shared by all archaic pili carrying two-domain adhesins. The use of flexible fingers instead of classical receptor-binding cavities is presumably more advantageous for attachment to structurally variable substrates, such as abiotic surfaces.}, } @article {pmid29734657, year = {2018}, author = {Zhang, G and Liu, J and Li, R and Jiao, S and Feng, C and Wang, ZA and Du, Y}, title = {Conjugation of Inulin Improves Anti-Biofilm Activity of Chitosan.}, journal = {Marine drugs}, volume = {16}, number = {5}, pages = {}, pmid = {29734657}, issn = {1660-3397}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Cell Line, Tumor ; Chitosan/*chemistry ; Hep G2 Cells ; Humans ; Inulin/*chemistry ; Mice ; Microbial Sensitivity Tests/methods ; RAW 264.7 Cells ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects ; }, abstract = {Bacteria biofilm helps bacteria prevent phagocytosis during infection and increase resistance to antibiotics. Staphylococcus aureus is a Gram-positive pathogenic bacterium and is tightly associated with biofilm-related infections, which have led to great threat to human health. Chitosan, the only cationic polysaccharide in nature, has been demonstrated to have antimicrobial and anti-biofilm activities, which, however, require a relative high dosage of chitosan. Moreover, poor water solubility further restricts its applications on anti-infection therapy. Inulins are a group of polysaccharides produced by many types of plants, and are widely used in processed foods. Compared to chitosan, inulin is very soluble in water and possesses a mild antibacterial activity against certain pathogenic bacteria. In order to develop an effective strategy to treat biofilm-related infections, we introduce a method by covalent conjugation of inulin to chitosan. The physicochemical characterization of the inulin[-]chitosan conjugate was assayed, and the anti-biofilm activity was evaluated against S. aureus biofilm. The results indicated that, as compared to chitosan, this novel polysaccharide[-]polysaccharide conjugate significantly enhanced activities against S. aureus either in a biofilm or planktonic state. Of note, the conjugate also showed a broad spectrum anti-biofilm activity on different bacteria strains and low cellular toxicity to mammalian cells. These results suggested that chitosan conjugation of inulin was a viable strategy for treatment against biofilm-related infections. This finding may further spread the application of natural polysaccharides on treatments of infectious disease.}, } @article {pmid29733348, year = {2018}, author = {Rea, MA and Standish, CD and Shuster, J and Bissett, A and Reith, F}, title = {Progressive biogeochemical transformation of placer gold particles drives compositional changes in associated biofilm communities.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {6}, pages = {}, doi = {10.1093/femsec/fiy080}, pmid = {29733348}, issn = {1574-6941}, mesh = {Bacteria/*classification/genetics/*isolation & purification ; Biofilms/drug effects/*growth & development ; Gold/*metabolism ; High-Throughput Nucleotide Sequencing ; Microbiota/*drug effects ; RNA, Ribosomal, 16S/genetics ; United Kingdom ; }, abstract = {Biofilms on placer gold (Au)-particle surfaces drive Au solubilization and re-concentration thereby progressively transforming the particles. Gold solubilization induces Au-toxicity; however, Au-detoxifying community members ameliorates Au-toxicity by precipitating soluble Au to metallic Au. We hypothesize that Au-dissolution and re-concentration (precipitation) place selective pressures on associated microbial communities, leading to compositional changes and subsequent Au-particle transformation. We analyzed Au-particles from eight United Kingdom sites using next generation sequencing, electron microscopy and micro-analyses. Gold particles contained biofilms composed of prokaryotic cells and extracellular polymeric substances intermixed with (bio)minerals. Across all sites communities were dominated by Proteobacteria (689, 97% Operational Taxonomic Units, 59.3% of total reads), with β-Proteobacteria being the most abundant. A wide range of Au-morphotypes including nanoparticles, micro-crystals, sheet-like Au and secondary rims, indicated that dissolution and re-precipitation occurred, and from this transformation indices were calculated. Multivariate statistical analyses showed a significant relationship between the extent of Au-particle transformation and biofilm community composition, with putative metal-resistant Au-cycling taxa linked to progressive Au transformation. These included the genera Pseudomonas, Leptothrix and Acinetobacter. Additionally, putative exoelectrogenic genera Rhodoferax and Geobacter were highly abundant. In conclusion, biogeochemical Au-cycling and Au-particle transformation occurred at all sites and exerted a strong influence on biofilm community composition.}, } @article {pmid29732747, year = {2018}, author = {Wang, WD and Zhang, NN and Chanda, W and Liu, M and Din, SRU and Diao, YP and Liu, L and Cao, J and Wang, XL and Li, XY and Ning, AH and Huang, M and Zhong, MT}, title = {Antibacterial and anti-biofilm activity of the lipid extract from Mantidis ootheca on Pseudomonas aeruginosa.}, journal = {Journal of Zhejiang University. Science. B}, volume = {19}, number = {5}, pages = {364-371}, pmid = {29732747}, issn = {1862-1783}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Gas Chromatography-Mass Spectrometry ; *Mantodea/chemistry ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Mantidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the lipid extract and its relative proportion were determined using the technique of gas chromatography coupled with mass spectrometry (GC-MS). Antibacterial susceptibility tests were performed using a disc diffusion assay and the minimum inhibition concentration (MIC) was determined by way of the agar dilution method. The anti-biofilm test was carried out with crystal violet staining and scanning electron microscopy (SEM). There were 16 compounds detected, and the most abundant components were sesquiterpenoids, monoterpenes, and trace aromatic compounds. The MIC for P. aeruginosa was 4 mg/ml and the eradication effect on preformed biofilms was established and compared with a ciprofloxacin control. The results of our study indicated that a lipid extract from M. ootheca could be used as a topical and antibacterial agent with anti-biofilm activity in the future.}, } @article {pmid29731649, year = {2018}, author = {Shrestha, LB and Bhattarai, NR and Khanal, B}, title = {Comparative evaluation of methods for the detection of biofilm formation in coagulase-negative staphylococci and correlation with antibiogram.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {607-613}, pmid = {29731649}, issn = {1178-6973}, abstract = {INTRODUCTION: Coagulase-negative staphylococci (CNS) are normal commensals of human skin and mucous membranes. The objective of the study was to determine the prevalence of CNS among clinical isolates, characterize them up to species level, compare the three conventional methods for detection of biofilm formation, and study their antimicrobial susceptibility pattern.

MATERIALS AND METHODS: CNS were obtained from various clinical samples including blood, urine, central venous catheter tips, endotracheal tube aspirate, and pus during a 1-year period (July 1, 2014, to June 30, 2015). Characterization up to species level was done using biochemical tests, and biofilm formation was detected by tube adherence, Congo red agar, and tissue culture plate method. Antimicrobial susceptibility testing was performed following Clinical and Laboratory Standards Institute guidelines.

RESULTS: A total of 71 CNS isolates, comprising of seven species were obtained. Staphylococcus epidermidis was the most common species followed by S. saprophyticus and S. haemolyticus. We detected biofilm formation in 71.8% of isolates. Considering the fact that tissue culture plate method is the gold standard, sensitivity of tube adherence method and Congo red agar method was found as 82% and 78%, respectively. The isolates exhibited high resistance toward penicillin (90%), azithromycin (60%), co-trimoxazole (60%), and ceftriaxone (40%), while all were susceptible to vancomycin and linezolid. Biofilm former isolates showed higher resistance than the non-formers.

CONCLUSION: Among 71 CNS isolated, S. epidermidis was the most common isolate followed by S. saprophyticus and S. haemolyticus. Biofilm formation was detected in 71.8% of the isolates. All of the methods were effective in detecting biofilm-producing CNS strains. The antimicrobial resistance was significantly higher in biofilm formers than non-formers.}, } @article {pmid29730068, year = {2018}, author = {Hasby Saad, MA and Khalil, HSM}, title = {Biofilm testing of microbiota: An essential step during corneal scrap examination in Egyptian acanthamoebic keratitis cases.}, journal = {Parasitology international}, volume = {67}, number = {5}, pages = {556-564}, doi = {10.1016/j.parint.2018.05.001}, pmid = {29730068}, issn = {1873-0329}, mesh = {Acanthamoeba/*isolation & purification/ultrastructure ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; *Coinfection/microbiology/parasitology ; Contact Lenses/microbiology/parasitology ; Cornea/microbiology/parasitology/ultrastructure ; Corneal Transplantation ; Drug Resistance, Multiple ; Enterobacteriaceae/isolation & purification ; Female ; Humans ; Keratitis/*parasitology ; Male ; Microbial Sensitivity Tests ; *Microbiota ; Microscopy, Electron, Transmission ; Parasitic Diseases/*complications/microbiology ; }, abstract = {PURPOSE: To detect co-infections in the culture-proven acanthamoebic keratitis (AK) cases, and to test the capability of biofilm formation in the isolated microbiota. The clinical findings, habit of wearing contact lens and in-vitro antibiotic resistance were analyzed further according to the biofilm formation capability.

METHODS: After clinical examination, corneal scraps and swabs were taken from 240 clinically suspected AK cases, for Acanthamoeba and microbiological cultures. In cases of keratoplasty, trimmed corneal tissue was collected and sent for histopathological examination. Scanning electron microscopy was done for some samples. Biofilm formation capability was investigated using a tissue culture plate method. Antibiotic resistance pattern was determined using a modified-Kirby-Bauer disc diffusion method.

RESULTS: In 102 AK culture proven cases, 11 had no co-infection, 74 had a single co-infection and 17 had double co-infections. Enterobactericae and Aspergillus were the commonest bacterial and fungal isolates, respectively. Regarding the biofilm formation, 64.7% of Enterobactericae, 50% of Pseudomonas aeuroginosa, 43.75% of Staph aureus, 76.92% of Streptococcus pneumoniae, 28.57% of Corynebacterium, 60% of α-haemolytic streptococci, 40% of Acinetobacter, 100% of Candida and 77.8% Aspergillus isolates were biofilm producers. Severe manifestations were more frequently reported in cases co-infected with biofilm producers than with non-biofilm producers. Generally, high percentages of the biofilm forming bacterial isolates were sensitive to antibiotics in-vitro.

CONCLUSIONS: Routine investigations for co-infection and biofilm formation in addition to Acanthamoeba culture are strongly recommended in suspected AK cases. Co-infection with biofilm producers may precipitate extrinsic in-vivo drug resistance despite of the in-vitro sensitivity. Designing a biofilm-dissolving topical drug is highly recommended to enhance the response to the standard therapeutic regimen especially in the resistant AK cases.}, } @article {pmid29729997, year = {2018}, author = {Gilmore, BF and Flynn, PB and O'Brien, S and Hickok, N and Freeman, T and Bourke, P}, title = {Cold Plasmas for Biofilm Control: Opportunities and Challenges.}, journal = {Trends in biotechnology}, volume = {36}, number = {6}, pages = {627-638}, doi = {10.1016/j.tibtech.2018.03.007}, pmid = {29729997}, issn = {1879-3096}, support = {R01 AR051303/AR/NIAMS NIH HHS/United States ; R01 AR069119/AR/NIAMS NIH HHS/United States ; R01 AR072513/AR/NIAMS NIH HHS/United States ; R01 EB013011/EB/NIBIB NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/chemistry/*drug effects/growth & development/metabolism ; Bacterial Infections/microbiology/*therapy ; DNA, Bacterial/chemistry/metabolism ; Drug Resistance, Multiple, Bacterial ; Extracellular Polymeric Substance Matrix/chemistry/*drug effects/metabolism ; Humans ; Lipids/chemistry ; Microbial Sensitivity Tests ; Plasma Gases/chemistry/*pharmacology ; Polysaccharides, Bacterial/chemistry/metabolism ; Quorum Sensing/drug effects ; Reactive Nitrogen Species/agonists/metabolism ; Reactive Oxygen Species/agonists/metabolism ; }, abstract = {Bacterial biofilm infections account for a major proportion of chronic and medical device associated infections in humans, yet our ability to control them is compromised by their inherent tolerance to antimicrobial agents. Cold atmospheric plasma (CAP) represents a promising therapeutic option. CAP treatment of microbial biofilms represents the convergence of two complex phenomena: the production of a chemically diverse mixture of reactive species and intermediates, and their interaction with a heterogeneous 3D interface created by the biofilm extracellular polymeric matrix. Therefore, understanding these interactions and physiological responses to CAP exposure are central to effective management of infectious biofilms. We review the unique opportunities and challenges for translating CAP to the management of biofilms.}, } @article {pmid29729630, year = {2018}, author = {Doiron, K and Beaulieu, L and St-Louis, R and Lemarchand, K}, title = {Reduction of bacterial biofilm formation using marine natural antimicrobial peptides.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {167}, number = {}, pages = {524-530}, doi = {10.1016/j.colsurfb.2018.04.051}, pmid = {29729630}, issn = {1873-4367}, mesh = {Amino Acid Sequence ; Animals ; Anti-Infective Agents/*pharmacology ; Aquatic Organisms/chemistry ; Bacteria/classification/*drug effects/growth & development ; Biofilms/*drug effects ; Biofouling/prevention & control ; Biological Products/*pharmacology ; Brachyura/*chemistry ; Peptides/*pharmacology ; Steel/chemistry ; Surface Properties ; }, abstract = {There is an important need for the development of new "environmentally-friendly" antifouling molecules to replace toxic chemicals actually used to fight against marine biofouling. Marine biomass is a promising source of non-toxic antifouling products such as natural antimicrobial peptides produced by marine organisms. The aim of this study was to demonstrate the efficiency of antimicrobial peptides extracted from snow crab (SCAMPs) to reduce the formation of marine biofilms on immerged mild steel surfaces. Five antimicrobial peptides were found in the snow crab hydrolysate fraction used in this study. SCAMPs were demonstrated to interact with natural organic matter (NOM) during the formation of the conditioning film and to limit the marine biofilm development in terms of viability and bacterial structure. Natural SCAMPs could be considered as a potential alternative and non-toxic product to reduce biofouling, and as a consequence microbial induced corrosion on immerged surfaces.}, } @article {pmid29729516, year = {2018}, author = {Barral-Fraga, L and Martiñá-Prieto, D and Barral, MT and Morin, S and Guasch, H}, title = {Mutual interaction between arsenic and biofilm in a mining impacted river.}, journal = {The Science of the total environment}, volume = {636}, number = {}, pages = {985-998}, doi = {10.1016/j.scitotenv.2018.04.287}, pmid = {29729516}, issn = {1879-1026}, mesh = {Arsenic/*analysis ; *Biofilms ; *Environmental Monitoring ; Geologic Sediments ; Mining ; Spain ; Water Pollutants, Chemical/*analysis ; }, abstract = {Gold mining activities in fluvial systems may cause arsenic (As) pollution, as is the case at the Anllóns River (Galicia, NW Spain), where high concentrations of arsenate (As[V]) in surface sediments (up to 270 mg kg[-1]) were found. A 51 day-long biofilm-translocation experiment was performed in this river, moving some biofilm-colonized substrata from upstream (less As-polluted) to downstream the mine area (more As-polluted site), to explore the effect of As on benthic biofilms, as well as their role on As retention and speciation in the water-sediment interface. Eutrophic conditions (range: 0.07-0.38 mg L[-1] total phosphorus, TP) were detected in water in both sites, while sediments were not considered P-polluted (below 600 mg kg[-1]). Dimethylarsenate (DMA[V]) was found intracellularly and in the river water, suggesting a detoxification process by biofilms. Since most As in sediments and water was As[V], the high amount of arsenite (As[III]) detected extracellularly may also confirm As[V] reduction by biofilms. Furthermore, translocated biofilms accumulated more As and showed higher potential toxicity (higher As/P ratio). In concordance, their growth was reduced to half that observed in those non-translocated, became less nutritive (less nitrogen content), and with higher bacterial and dead diatom densities. Besides the high As exposure, other environmental conditions such as the higher riparian cover at the more As-polluted site could contribute to those effects. Our study provides new arguments to understand the contribution of microorganisms to the As biogeochemistry in freshwater environments.}, } @article {pmid29728966, year = {2018}, author = {Covarrubias-García, I and Aizpuru, A and Arriaga, S}, title = {Temporal and longitudinal biofilm matrix analysis of a biofilter treating ethyl acetate during ozonation.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {19}, pages = {19155-19166}, pmid = {29728966}, issn = {1614-7499}, support = {SEP-CONACYT-CB-2014-01-239622//Consejo Nacional de Ciencia y Tecnología/ ; }, mesh = {Acetates/*chemistry ; Biofilms ; Biomass ; Extracellular Polymeric Substance Matrix ; Ozone/analysis/*chemistry ; Water Purification/*methods ; }, abstract = {The present paper focuses on the biofilm composition and pattern of biomass in gas biofiltration of ethyl acetate working under continuous addition of ozone (O3). Two biofilters were operated for 230 days, one under continuous addition of O3 (90 ppbv) and another one without. Throughout the operation time, the extracellular polymeric substances (EPS), the main components in the extracellular matrix (ECM), were extracted from the biofilm and characterized qualitatively using Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and quantitatively by analyzing its main constituents: carbohydrates, proteins, and glucuronic acid. To date, EPS characterization has been attempted mainly with biofilm aggregates related to water treatment, not air biofiltration. The results of this study may be helpful and provide more information about EPS structure when O3 was added. O3 addition only affected the amount of EPS and not its composition. The greater effect was observed on carbohydrate content since it is the main component in EPS. The EPS/biomass ratio measured was twice lower with O3 addition. Higher removal efficiency (RE) and mineralization rates were obtained with the biofilter subjected to O3 addition, and a smaller volume of a reactor would be necessary to treat all contaminant under this condition. EPS content is only quantitatively reduced by O3 addition, and at the low O3 concentration applied, no structural alteration is noted regarding the composition of the EPS.}, } @article {pmid29728008, year = {2018}, author = {Gomes, IB and Lemos, M and Mathieu, L and Simões, M and Simões, LC}, title = {The action of chemical and mechanical stresses on single and dual species biofilm removal of drinking water bacteria.}, journal = {The Science of the total environment}, volume = {631-632}, number = {}, pages = {987-993}, doi = {10.1016/j.scitotenv.2018.03.042}, pmid = {29728008}, issn = {1879-1026}, mesh = {Biofilms/growth & development ; Disinfectants/toxicity ; Disinfection/*methods ; Drinking Water/microbiology ; Sodium Hypochlorite/toxicity ; Stress, Mechanical ; Water Purification/*methods ; }, abstract = {The presence of biofilms in drinking water distribution systems (DWDS) is a global public health concern as they can harbor pathogenic microorganisms. Sodium hypochlorite (NaOCl) is the most commonly used disinfectant for microbial growth control in DWDS. However, its effect on biofilm removal is still unclear. This work aims to evaluate the effects of the combination of chemical (NaOCl) and mechanical stresses on the removal of single and dual species biofilms of two bacteria isolated from DWDS and considered opportunistic, Acinectobacter calcoaceticus and Stenotrophomonas maltophilia. A rotating cylinder reactor was successfully used for the first time in drinking water biofilm studies with polyvinyl chloride as substratum. The single and dual species biofilms presented different characteristics in terms of metabolic activity, mass, density, thickness and content of proteins and polysaccharides. Their complete removal was not achieved even when a high NaOCl concentrations and an increasing series of shear stresses (from 2 to 23Pa) were applied. In general, NaOCl pre-treatment did not improve the impact of mechanical stress on biofilm removal. Dual species biofilms were colonized mostly by S. maltophilia and were more susceptible to chemical and mechanical stresses than these single species. The most efficient treatment (93% biofilm removal) was the combination of NaOCl at 175mg·l[-1] with mechanical stress against dual species biofilms. Of concern was the high tolerance of S. maltophilia to chemical and mechanical stresses in both single and dual species biofilms. The overall results demonstrate the inefficacy of NaOCl on biofilm removal even when combined with high shear stresses.}, } @article {pmid29726716, year = {2018}, author = {Cattò, C and James, G and Villa, F and Villa, S and Cappitelli, F}, title = {Zosteric acid and salicylic acid bound to a low density polyethylene surface successfully control bacterial biofilm formation.}, journal = {Biofouling}, volume = {34}, number = {4}, pages = {440-452}, doi = {10.1080/08927014.2018.1462342}, pmid = {29726716}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Cinnamates/chemistry/*pharmacology ; Escherichia coli/*drug effects/physiology ; Microbial Viability ; Polyethylene/*chemistry ; Salicylic Acid/chemistry/*pharmacology ; Sulfuric Acid Esters/chemistry/*pharmacology ; }, abstract = {The active moieties of the anti-biofilm natural compounds zosteric (ZA) and salicylic (SA) acids have been covalently immobilized on a low density polyethylene (LDPE) surface. The grafting procedure provided new non-toxic eco-friendly materials (LDPE-CA and LDPE-SA) with anti-biofilm properties superior to the conventional biocide-based approaches and with features suitable for applications in challenging fields where the use of antimicrobial agents is limited. Microbiological investigation proved that LDPE-CA and LDPE-SA: (1) reduced Escherichia coli biofilm biomass by up to 61% with a mechanism that did not affect bacterial viability; (2) significantly affected biofilm morphology, decreasing biofilm thickness, roughness, substratum coverage, cell and matrix polysaccharide bio-volumes by >80% and increasing the surface to bio-volume ratio; (3) made the biofilm more susceptible to ampicillin and ethanol. Since no molecules were leached from the surface, they remained constantly effective and below the lethal level; therefore, the risk of inducing resistance was minimized.}, } @article {pmid29726711, year = {2019}, author = {Kwiecińska-Piróg, J and Skowron, K and Śniegowska, A and Przekwas, J and Balcerek, M and Załuski, D and Gospodarek-Komkowska, E}, title = {The impact of ethanol extract of propolis on biofilm forming by Proteus Mirabilis strains isolated from chronic wounds infections.}, journal = {Natural product research}, volume = {33}, number = {22}, pages = {3293-3297}, doi = {10.1080/14786419.2018.1470513}, pmid = {29726711}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Ethanol/chemistry ; Humans ; Propolis/*pharmacology ; Proteus Infections/*drug therapy ; Proteus mirabilis/*ultrastructure ; Wound Healing/drug effects ; Wounds and Injuries/*microbiology ; }, abstract = {Alcoholic propolis extracts may be used to eliminate microbes in mucous membranes and skin inflammations and in wound infections. The aim of this study was an assessment of the ethanol extract of propolis (EEP) activity against biofilm formation by P. mirabilis. Six clinical strains of P. mirabilis isolated from patients with chronic wound infection, and one reference strain of P. mirabilis ATCC 29906 were used. Biofilm was formed in 96-well plate. In order to evaluate the effect of EEP at a concentration range of 1.56-100 mg/mL on the forming and mature biofilm, P. mirabilis cells were released by sonication. In this study the effectiveness of 25-100 mg/mL of EEP on the forming P. mirabilis biofilm and concentrations of 25-50 mg/mL of EEP on formed biofilm has been demonstrated. Our results suggest the possibility of using the EEP in treatment of chronic wound infection caused by P. mirabilis.}, } @article {pmid29725253, year = {2018}, author = {Kim, HR and Lee, D and Eom, YB}, title = {Anti-biofilm and Anti-Virulence Efficacy of Celastrol Against Stenotrophomonas maltophilia.}, journal = {International journal of medical sciences}, volume = {15}, number = {6}, pages = {617-627}, pmid = {29725253}, issn = {1449-1907}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Bacterial Proteins/genetics ; Biofilms/drug effects ; Cross Infection/*drug therapy/microbiology/pathology ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Pentacyclic Triterpenes ; Stenotrophomonas maltophilia/*drug effects/pathogenicity ; Triterpenes/*administration & dosage ; Virulence/drug effects ; }, abstract = {Stenotrophomonas maltophilia is a multi-drug resistant opportunistic pathogen that causes nosocomial infections in immunocompromised patients. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of celastrol as a novel anti-biofilm and/or anti-virulence agent against S. maltophilia. Results showed that celastrol at its sub-inhibitory doses decreased biofilm formation and disrupt the established biofilms produced by S. maltophilia. Celastrol-induced decrease in biofilm formation was dose-dependent based on the results of the microtiter plate biofilm assays and confocal laser scanning microscopy. In addition, our data validated the anti-virulence efficacy of celastrol, wherein it significantly interfered with the production of protease and motility of S. maltophilia. To support these phenotypic results, transcriptional analysis revealed that celastrol down-regulated the expression of biofilm- and virulence- associated genes (smeYZ, fsnR, and bfmAK) in S. maltophilia. Interestingly, celastrol significantly inhibited the expression of smeYZ gene, which encodes the resistance-nodulation-division (RND)-type efflux pump, SmeYZ. Overall, our findings suggested that celastrol might be a promising bioactive agent for treatment of biofilm- and virulence-related infections caused by the multi-drug resistant S. maltophilia.}, } @article {pmid29723434, year = {2018}, author = {Schmitt, A and Jiang, K and Camacho, MI and Jonna, VR and Hofer, A and Westerlund, F and Christie, PJ and Berntsson, RP}, title = {PrgB promotes aggregation, biofilm formation, and conjugation through DNA binding and compaction.}, journal = {Molecular microbiology}, volume = {109}, number = {3}, pages = {291-305}, pmid = {29723434}, issn = {1365-2958}, support = {R01 GM048746/GM/NIGMS NIH HHS/United States ; R21 AI105454/AI/NIAID NIH HHS/United States ; }, mesh = {Adherens Junctions/*physiology ; Adhesins, Bacterial/*chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Cell Line ; *Conjugation, Genetic ; DNA-Binding Proteins/chemistry/genetics/metabolism ; Enterococcus faecalis/genetics/*physiology ; Gene Transfer, Horizontal ; Lipopolysaccharides/chemistry/metabolism ; Plasmids/chemistry/genetics/metabolism ; Protein Binding ; Protein Conformation ; Teichoic Acids/chemistry/metabolism ; Type IV Secretion Systems ; }, abstract = {Gram-positive bacteria deploy type IV secretion systems (T4SSs) to facilitate horizontal gene transfer. The T4SSs of Gram-positive bacteria rely on surface adhesins as opposed to conjugative pili to facilitate mating. Enterococcus faecalis PrgB is a surface adhesin that promotes mating pair formation and robust biofilm development in an extracellular DNA (eDNA) dependent manner. Here, we report the structure of the adhesin domain of PrgB. The adhesin domain binds and compacts DNA in vitro. In vivo PrgB deleted of its adhesin domain does not support cellular aggregation, biofilm development and conjugative DNA transfer. PrgB also binds lipoteichoic acid (LTA), which competes with DNA binding. We propose that PrgB binding and compaction of eDNA facilitates cell aggregation and plays an important role in establishment of early biofilms in mono- or polyspecies settings. Within these biofilms, PrgB mediates formation and stabilization of direct cell-cell contacts through alternative binding of cell-bound LTA, which in turn promotes establishment of productive mating junctions and efficient intra- or inter-species T4SS-mediated gene transfer.}, } @article {pmid29723163, year = {2018}, author = {Macrae, FL and Duval, C and Papareddy, P and Baker, SR and Yuldasheva, N and Kearney, KJ and McPherson, HR and Asquith, N and Konings, J and Casini, A and Degen, JL and Connell, SD and Philippou, H and Wolberg, AS and Herwald, H and Ariëns, RA}, title = {A fibrin biofilm covers blood clots and protects from microbial invasion.}, journal = {The Journal of clinical investigation}, volume = {128}, number = {8}, pages = {3356-3368}, pmid = {29723163}, issn = {1558-8238}, support = {G1001502/MRC_/Medical Research Council/United Kingdom ; PG/16/60/32292/BHF_/British Heart Foundation/United Kingdom ; R01 HL126974/HL/NHLBI NIH HHS/United States ; RG/13/3/30104/BHF_/British Heart Foundation/United Kingdom ; }, mesh = {Animals ; Bacteria/*genetics/pathogenicity ; *Bacterial Physiological Phenomena ; *Biofilms ; *Blood Coagulation ; Disease Models, Animal ; Fibrin/*metabolism ; Humans ; Mice ; Skin Diseases, Bacterial/*metabolism/microbiology ; }, abstract = {Hemostasis requires conversion of fibrinogen to fibrin fibers that generate a characteristic network, interact with blood cells, and initiate tissue repair. The fibrin network is porous and highly permeable, but the spatial arrangement of the external clot face is unknown. Here we show that fibrin transitioned to the blood-air interface through Langmuir film formation, producing a protective film confining clots in human and mouse models. We demonstrated that only fibrin is required for formation of the film, and that it occurred in vitro and in vivo. The fibrin film connected to the underlying clot network through tethering fibers. It was digested by plasmin, and formation of the film was prevented with surfactants. Functionally, the film retained blood cells and protected against penetration by bacterial pathogens in a murine model of dermal infection. Our data show a remarkable aspect of blood clotting in which fibrin forms a protective film covering the external surface of the clot, defending the organism against microbial invasion.}, } @article {pmid29722806, year = {2018}, author = {Yates, MD and Barr Engel, S and Eddie, BJ and Lebedev, N and Malanoski, AP and Tender, LM}, title = {Redox-gradient driven electron transport in a mixed community anodic biofilm.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {6}, pages = {}, doi = {10.1093/femsec/fiy081}, pmid = {29722806}, issn = {1574-6941}, mesh = {Biofilms/growth & development ; *Electric Conductivity ; Electrodes ; Electron Transport/*physiology ; Electrons ; Geobacter/classification/*physiology ; Geologic Sediments/*microbiology ; Microscopy, Confocal ; Oxidation-Reduction ; Rivers/microbiology ; }, abstract = {Here, we describe the long-distance (multi-cell-length) extracellular electron transport (LD-EET) that occurs in an anode-grown mixed community biofilm (MCB) enriched from river sediment that contains 3%-45% Geobacter spp. High signal-to-noise temperature-dependent electrochemical gating measurements (EGM) using interdigitated microelectrode arrays reveal a peak-shaped electrical conductivity vs. potential dependency, indicating MCB acts as a redox conductor, similar to pure culture anode-grown Geobacter sulfurreducens biofilms (GSB). EGM also reveal that the maximum sustained rate of LD-EET in MCB is comparable to GSB, and the same whether under acetate-oxidizing or acetate-free conditions. Voltammetry indicated that MCB possesses 3- to 5-fold less electrode-accessible redox cofactors than GSB, suggesting that MCB may be more efficiently organized than GSB for LD-EET or that a small portion of electrode accessible redox cofactors of GSB are involved in LD-EET. The activation energy for LD-EET (0.11 ± 0.01 eV) was comparable to GSB, consistent with the possible role of c-type cytochromes as LD-EET cofactors, detected in abundance by confocal resonance Raman microscopy. Taken together, the results demonstrate LD-EET for a mixed community anode-grown microbial biofilm that is remarkably similar to GSB even though it contains many different types of microorganisms and appears to utilize far fewer EET redox cofactors.}, } @article {pmid29722582, year = {2018}, author = {El-Messery, SM and Habib, EE and Al-Rashood, STA and Hassan, GS}, title = {Synthesis, antimicrobial, anti-biofilm evaluation, and molecular modelling study of new chalcone linked amines derivatives.}, journal = {Journal of enzyme inhibition and medicinal chemistry}, volume = {33}, number = {1}, pages = {818-832}, pmid = {29722582}, issn = {1475-6374}, mesh = {Amines/chemistry/*pharmacology ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Chalcone/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Fungi/drug effects ; Gram-Positive Bacteria/cytology/drug effects ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {A series of amide chalcones conjugated with different secondary amines were synthesised and characterised by different spectroscopic techniques [1]H NMR, [13]C NMR, and ESI-MS. They were screened for in vitro antibacterial activity. Compounds 36, 37, 38, 42, and 44 are the most active among the synthesised series exhibiting MIC value of 2.0-10.0 µg/ml against different bacterial strains. Compound 36 was equipotent to the standard drug Ampicillin displaying MBC value of 2.0 µg/ml against the bacterial strain Staphylococcus aureus. The products were screened for anti-biofilm activity. Compounds 36, 37, and 38 exhibited promising anti-biofilm activity with IC50 value ranges from 2.4 to 8.6 µg. Molecular modelling was performed suggesting parameters of signalling anti-biofilm mechanism. AspB327 HisB340 (arene-arene interaction) and IleB328 amino acid residues seemed of higher importance to inhibit c-di-GMP. Hydrophobicity may be crucial for activity. ADME calculations suggested that compounds 36, 37, and 38 could be used as good orally absorbed anti-biofilm agents.}, } @article {pmid29720707, year = {2018}, author = {Arciola, CR and Campoccia, D and Montanaro, L}, title = {Implant infections: adhesion, biofilm formation and immune evasion.}, journal = {Nature reviews. Microbiology}, volume = {16}, number = {7}, pages = {397-409}, doi = {10.1038/s41579-018-0019-y}, pmid = {29720707}, issn = {1740-1534}, mesh = {Bacteria/*classification/immunology ; Bacterial Adhesion/*physiology ; Bacterial Infections/*immunology/microbiology ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Humans ; *Immune Evasion ; Prosthesis-Related Infections/immunology/*microbiology ; }, abstract = {Medical device-associated infections account for a large proportion of hospital-acquired infections. A variety of opportunistic pathogens can cause implant infections, depending on the type of the implant and on the anatomical site of implantation. The success of these versatile pathogens depends on rapid adhesion to virtually all biomaterial surfaces and survival in the hostile host environment. Biofilm formation on implant surfaces shelters the bacteria and encourages persistence of infection. Furthermore, implant-infecting bacteria can elude innate and adaptive host defences as well as biocides and antibiotic chemotherapies. In this Review, we explore the fundamental pathogenic mechanisms underlying implant infections, highlighting orthopaedic implants and Staphylococcus aureus as a prime example, and discuss innovative targets for preventive and therapeutic strategies.}, } @article {pmid29720089, year = {2018}, author = {Olwal, CO and Ang'ienda, PO and Onyango, DM and Ochiel, DO}, title = {Susceptibility patterns and the role of extracellular DNA in Staphylococcus epidermidis biofilm resistance to physico-chemical stress exposure.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {40}, pmid = {29720089}, issn = {1471-2180}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; DNA, Bacterial/analysis/*genetics ; Disinfection ; Hot Temperature/adverse effects ; Hydrogen Peroxide/pharmacology ; Microbial Sensitivity Tests ; Sodium Chloride/pharmacology ; Sodium Hypochlorite/pharmacology ; Staphylococcus epidermidis/*drug effects/*genetics ; *Stress, Physiological ; }, abstract = {BACKGROUND: Over 65% of human infections are ascribed to bacterial biofilms that are often highly resistant to antibiotics and host immunity. Staphylococcus epidermidis is the predominant cause of recurrent nosocomial and biofilm-related infections. However, the susceptibility patterns of S. epidermidis biofilms to physico-chemical stress induced by commonly recommended disinfectants [(heat, sodium chloride (NaCl), sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2)] in domestic and human healthcare settings remains largely unknown. Further, the molecular mechanisms of bacterial biofilms resistance to the physico-chemical stresses remain unclear. Growing evidence demonstrates that extracellular DNA (eDNA) protects bacterial biofilms against antibiotics. However, the role of eDNA as a potential mechanism underlying S. epidermidis biofilms resistance to physico-chemical stress exposure is yet to be understood. Therefore, this study aimed to evaluate the susceptibility patterns of and eDNA release by S. epidermidis biofilm and planktonic cells to physico-chemical stress exposure.

RESULTS: S. epidermidis biofilms exposed to physico-chemical stress conditions commonly recommended for disinfection [heat (60 °C), 1.72 M NaCl, solution containing 150 μL of waterguard (0.178 M NaOCl) in 1 L of water or 1.77 M H2O2] for 30 and 60 min exhibited lower log reductions of CFU/mL than the corresponding planktonic cells (p < 0.0001). The eDNA released by sub-lethal heat (50 °C)-treated S. epidermidis biofilm and planktonic cells was not statistically different (p = 0.8501). However, 50 °C-treated S. epidermidis biofilm cells released significantly increased eDNA than the untreated controls (p = 0.0098). The eDNA released by 0.8 M NaCl-treated S. epidermidis biofilm and planktonic cells was not significantly different (p = 0.9697). Conversely, 5 mM NaOCl-treated S. epidermidis biofilms exhibited significantly increased eDNA release than the corresponding planktonic cells (p = 0.0015). Further, the 50 μM H2O2-treated S. epidermidis biofilms released significantly more eDNA than the corresponding planktonic cells (p = 0.021).

CONCLUSIONS: S. epidermidis biofilms were less susceptible to physico-chemical stress induced by the four commonly recommended disinfectants than the analogous planktonic cells. Further, S. epidermidis biofilms enhanced eDNA release in response to the sub-lethal heat and oxidative stress exposure than the corresponding planktonic cells suggesting a role of eDNA in biofilms resistance to the physico-chemical stresses.}, } @article {pmid29719973, year = {2018}, author = {Fink, R and Kulaš, S and Oder, M}, title = {Efficacy of sodium dodecyl sulphate and natural extracts against E. coli biofilm.}, journal = {International journal of environmental health research}, volume = {28}, number = {3}, pages = {306-314}, doi = {10.1080/09603123.2018.1470230}, pmid = {29719973}, issn = {1369-1619}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Escherichia coli/*drug effects/physiology ; Fruit ; *Laurus ; *Lythraceae ; Plant Extracts/*pharmacology ; Plant Leaves ; Sodium Dodecyl Sulfate/*pharmacology ; Surface-Active Agents/*pharmacology ; *Vitis ; }, abstract = {The aim of this study was to determine and compare the efficacy of a standard cleaning agent, sodium dodecyl sulphate, and natural extracts from pomegranate peel grape skin and bay laurel leaf against E. coli biofilm. The biofilm was exposed for 10 minutes to three different concentrations of each tested compound. The results show that bay laurel leaf extract is the most efficient with 43% biofilm biomass reduction, followed by pomegranate peel extract (35%); sodium dodecyl sulphate and grape skin extract each have 30% efficacy. Our study demonstrated that natural extracts from selected plants have the same or even better efficacy against E. coli biofilm removal from surfaces than the tested classical cleaning agent do. All this indicates that natural plant extracts, which are acceptable from the health and environment points of view, can be potential substitutes for classical cleaning agents.}, } @article {pmid29719422, year = {2018}, author = {Dias, AP and Paschoal, MAB and Diniz, RS and Lage, LM and Gonçalves, LM}, title = {Antimicrobial action of chlorhexidine digluconate in self-ligating and conventional metal brackets infected with Streptococcus mutans biofilm.}, journal = {Clinical, cosmetic and investigational dentistry}, volume = {10}, number = {}, pages = {69-74}, pmid = {29719422}, issn = {1179-1357}, abstract = {OBJECTIVES: The objectives of this study were to assess the adherence of Streptococcus mutans biofilms grown over conventional ligature (CL) or self-ligating (SL) metal brackets and their bacterial viability after 0.12% chlorhexidine (CHX) digluconate treatment.

MATERIALS AND METHODS: The sample consisted of 48 metallic orthodontic brackets divided randomly into two groups: CL (n=24) and SL brackets (n=24). S. mutans biofilms were grown over the bracket surface (96 h) and treated with CHX (positive control) or 0.9% phosphate-buffered saline (PBS) (negative control) for 1 min each. Quantitative analysis was assessed by colony-forming units, and fluorescence microscopy was performed aiming to illustrate the outcomes. The tests were done in triplicate at three different times (n=9). Data were analyzed using ANOVA and Tukey test (P<0.05).

RESULTS: There were significant differences in brackets' biofilm formation, being CL largely colonized compared with SL, which was observed by colony-forming unit counting (P<0.05) and microcopy images. Significant reduction in the viability of S. mutans was found in both brackets treated with CHX compared to PBS (P<0.05).

CONCLUSION: The antimicrobial activities of CHX were similar for CL and SL brackets (P>0.05). In conclusion, a lower colonization was achieved in SL brackets and S. mutans biofilms were susceptible to CHX treatment to both studied brackets.}, } @article {pmid29718176, year = {2018}, author = {González, JF and Hahn, MM and Gunn, JS}, title = {Chronic biofilm-based infections: skewing of the immune response.}, journal = {Pathogens and disease}, volume = {76}, number = {3}, pages = {}, pmid = {29718176}, issn = {2049-632X}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; AI109002/NH/NIH HHS/United States ; AI116917/NH/NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Chronic Disease ; Cystic Fibrosis/*immunology/microbiology/pathology ; Cytokines/biosynthesis/immunology ; Host-Pathogen Interactions/*immunology ; Humans ; Immunity, Innate ; Mice ; Periodontitis/*immunology/microbiology/pathology ; Plankton/growth & development ; Pseudomonas Infections/*immunology/microbiology/pathology ; Pseudomonas aeruginosa/*immunology/pathogenicity ; Th1 Cells/immunology/microbiology ; Th1-Th2 Balance ; Th2 Cells/immunology/microbiology ; }, abstract = {Many of the deadliest bacterial diseases that plague humanity in the modern age are caused by bacterial biofilms that produce chronic infections. However, most of our knowledge of the host immune response comes from the study of planktonic pathogens. While there are similarities in the host response to planktonic and biofilm bacteria, specific immune responses toward biofilms have not been well studied; the only apparent difference is the inability to clear the bacteria allowing the biofilm infection to become chronic. In some cases, the biofilms skew T-cell response toward a balance that allows a stalemate between the host and the pathogen, in which the infection can become persistent. In this minireview, we will summarize well-known examples of this phenomena as well as some emerging studies that may indicate that this situation is much more common than initially thought.}, } @article {pmid29717970, year = {2018}, author = {Kumari, A and Mankotia, S and Chaubey, B and Luthra, M and Singh, R}, title = {Role of biofilm morphology, matrix content and surface hydrophobicity in the biofilm-forming capacity of various Candida species.}, journal = {Journal of medical microbiology}, volume = {67}, number = {6}, pages = {889-892}, doi = {10.1099/jmm.0.000747}, pmid = {29717970}, issn = {1473-5644}, abstract = {The present study aimed to evaluate the role of biofilm morphology, matrix content and surface hydrophobicity in the biofilm-forming capacity of Candida albicans and non-albicans Candida (NAC) spp. Biofilm formation was determined by microtitre plate assay and bright-field and scanning electron microscopy. The matrix carbohydrates, proteins and e-DNA were quantified by phenol-sulfuric acid, bicinchoninic acid and UV spectroscopy, respectively. Specific glycosyl residues were detected by dot blot. The cell-surface hydrophobicity was determined by hydrocarbon adhesion assay. Candida tropicalis was found to exhibit the highest adherence to polystyrene. It formed dense biofilms with extensive pseudohyphae and hyphal elements, high hydrophobicity and the greatest amount of matrix carbohydrates, proteins and e-DNA. C. albicans displayed higher adherence and a complex biofilm morphology with larger aggregates than Candida parapsilosis and Candida krusei, but had lower matrix content and hydrophobicity. Thus, the combinatorial effect of increased filamentation, maximum matrix content and high hydrophobicity contributes to the enhanced biofilm-forming capacity of C. tropicalis.}, } @article {pmid29717806, year = {2018}, author = {Jin, Z and Nie, M and Hu, R and Zhao, T and Xu, J and Chen, D and Yun, J and Ma, LZ and Du, W}, title = {Dynamic Sessile-Droplet Habitats for Controllable Cultivation of Bacterial Biofilm.}, journal = {Small (Weinheim an der Bergstrasse, Germany)}, volume = {14}, number = {22}, pages = {e1800658}, doi = {10.1002/smll.201800658}, pmid = {29717806}, issn = {1613-6829}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Flagella/drug effects/metabolism ; Hydrodynamics ; Microbial Sensitivity Tests ; Microfluidics/*methods ; Mutation/genetics ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Bacterial biofilms play essential roles in biogeochemical cycling, degradation of environmental pollutants, infection diseases, and maintenance of host health. The lack of quantitative methods for growing and characterizing biofilms remains a major challenge in understanding biofilm development. In this study, a dynamic sessile-droplet habitat is introduced, a simple method which cultivates biofilms on micropatterns with diameters of tens to hundreds of micrometers in a microfluidic channel. Nanoliter plugs are utilized, spaced by immiscible carrier oil to initiate and support the growth of an array of biofilms, anchored on and spatially confined to the micropatterns arranged on the bottom surface of the microchannel, while planktonic or dispersal cells are flushed away by shear force of aqueous plugs. The performance of the aforementioned method of cultivating biofilms is demonstrated by Pseudomonas aeruginosa PAO1 and its derived mutants, and quantitative antimicrobial susceptibility testing of PAO1 biofilms. This method could significantly eliminate corner effects, avoid microchannel clogging, and constrain the growth of biofilms for long-term observations. The controllable sessile droplet-based biofilm cultivation presented in this study should shed light on more quantitative and long-term studies of biofilms, and open new avenues for investigation of biofilm attachment, growth, expansion, and eradication.}, } @article {pmid29717024, year = {2018}, author = {Groenewold, MK and Massmig, M and Hebecker, S and Danne, L and Magnowska, Z and Nimtz, M and Narberhaus, F and Jahn, D and Heinz, DW and Jänsch, L and Moser, J}, title = {A phosphatidic acid-binding protein is important for lipid homeostasis and adaptation to anaerobic biofilm conditions in Pseudomonas aeruginosa.}, journal = {The Biochemical journal}, volume = {475}, number = {11}, pages = {1885-1907}, doi = {10.1042/BCJ20180257}, pmid = {29717024}, issn = {1470-8728}, mesh = {Adaptation, Biological ; Anaerobiosis ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Homeostasis ; Humans ; Phosphatidic Acids/*metabolism ; Pseudomonas Infections/*metabolism/microbiology ; Pseudomonas aeruginosa/genetics/*physiology ; }, abstract = {A quantitative Pseudomonas aeruginosa proteomics approach revealed increased abundance of the so-far uncharacterized protein PA3911 in anaerobic biofilms grown under conditions of the cystic fibrosis lung. Physiological relevance of ORF PA3911 was demonstrated, inter alia, using phenotype microarray experiments. The mutant strain showed increased susceptibility in the presence of antimicrobials (minocycline, nafcillin, oxacillin, chloramphenicol and thiamphenicol), enhanced twitching motility and significantly impaired biofilm formation. PA3911 is a soluble, cytoplasmic protein in P. aeruginosa In protein-lipid overlay experiments, purified PA3911 bound specifically to phosphatidic acid (PA), the central hub of phospholipid metabolism. Structure-guided site-directed mutagenesis was used to explore the proposed ligand-binding cavity of PA3911. Protein variants of Leu[56], Leu[58], Val[69] and Leu[114] were shown to impair PA interaction. A comparative shotgun lipidomics approach demonstrated a multifaceted response of P. aeruginosa to anaerobic conditions at the lipid head group and fatty acid level. Lipid homeostasis in the PA3911 mutant strain was imbalanced with respect to lysophosphatidylcholine, phosphatidylcholine and diacylglycerol under anaerobic and/or aerobic conditions. The impact of the newly identified PA-binding protein on lipid homeostasis and the related macroscopic phenotypes of P. aeruginosa are discussed.}, } @article {pmid29715620, year = {2018}, author = {Hrubanova, K and Nebesarova, J and Ruzicka, F and Krzyzanek, V}, title = {The innovation of cryo-SEM freeze-fracturing methodology demonstrated on high pressure frozen biofilm.}, journal = {Micron (Oxford, England : 1993)}, volume = {110}, number = {}, pages = {28-35}, doi = {10.1016/j.micron.2018.04.006}, pmid = {29715620}, issn = {1878-4291}, mesh = {Biofilms ; Candida albicans/*ultrastructure ; Candida parapsilosis/*ultrastructure ; Cryoelectron Microscopy/*methods ; Extracellular Matrix/*ultrastructure ; Freeze Fracturing/*methods ; Microscopy, Electron, Scanning/*methods ; Staphylococcus epidermidis/*ultrastructure ; }, abstract = {In this study we present an innovative method for the preparation of fully hydrated samples of microbial biofilms of cultures Staphylococcus epidermidis, Candida parapsilosis and Candida albicans. Cryo-scanning electron microscopy (cryo-SEM) and high-pressure freezing (HPF) rank among cutting edge techniques in the electron microscopy of hydrated samples such as biofilms. However, the combination of these techniques is not always easily applicable. Therefore, we present a method of combining high-pressure freezing using EM PACT2 (Leica Microsystems), which fixes hydrated samples on small sapphire discs, with a high resolution SEM equipped with the widely used cryo-preparation system ALTO 2500 (Gatan). Using a holder developed in house, a freeze-fracturing technique was applied to image and investigate microbial cultures cultivated on the sapphire discs. In our experiments, we focused on the ultrastructure of the extracellular matrix produced during cultivation and the relationships among microbial cells in the biofilm. The main goal of our investigations was the detailed visualization of areas of the biofilm where the microbial cells adhere to the substrate/surface. We show the feasibility of this technique, which is clearly demonstrated in experiments with various freeze-etching times.}, } @article {pmid29715298, year = {2018}, author = {Bogachev, MI and Volkov, VY and Markelov, OA and Trizna, EY and Baydamshina, DR and Melnikov, V and Murtazina, RR and Zelenikhin, PV and Sharafutdinov, IS and Kayumov, AR}, title = {Fast and simple tool for the quantification of biofilm-embedded cells sub-populations from fluorescent microscopic images.}, journal = {PloS one}, volume = {13}, number = {5}, pages = {e0193267}, pmid = {29715298}, issn = {1932-6203}, mesh = {*Algorithms ; Bacteria/*growth & development ; Biofilms/*growth & development ; Colonic Neoplasms/*pathology ; Flow Cytometry/*methods ; Humans ; Image Processing, Computer-Assisted/*methods ; Microscopy, Fluorescence/*methods ; Single-Cell Analysis/methods ; Software ; Tumor Cells, Cultured ; }, abstract = {Fluorescent staining is a common tool for both quantitative and qualitative assessment of pro- and eukaryotic cells sub-population fractions by using microscopy and flow cytometry. However, direct cell counting by flow cytometry is often limited, for example when working with cells rigidly adhered either to each other or to external surfaces like bacterial biofilms or adherent cell lines and tissue samples. An alternative approach is provided by using fluorescent microscopy and confocal laser scanning microscopy (CLSM), which enables the evaluation of fractions of cells subpopulations in a given sample. For the quantitative assessment of cell fractions in microphotographs, we suggest a simple two-step algorithm that combines single cells selection and the statistical analysis. To facilitate the first step, we suggest a simple procedure that supports finding the balance between the detection threshold and the typical size of single cells based on objective cell size distribution analysis. Based on a series of experimental measurements performed on bacterial and eukaryotic cells under various conditions, we show explicitly that the suggested approach effectively accounts for the fractions of different cell sub-populations (like the live/dead staining in our samples) in all studied cases that are in good agreement with manual cell counting on microphotographs and flow cytometry data. This algorithm is implemented as a simple software tool that includes an intuitive and user-friendly graphical interface for the initial adjustment of algorithm parameters to the microphotographs analysis as well as for the sequential analysis of homogeneous series of similar microscopic images without further user intervention. The software tool entitled BioFilmAnalyzer is freely available online at https://bitbucket.org/rogex/biofilmanalyzer/downloads/.}, } @article {pmid29713380, year = {2018}, author = {Chignell, JF and De Long, SK and Reardon, KF}, title = {Meta-proteomic analysis of protein expression distinctive to electricity-generating biofilm communities in air-cathode microbial fuel cells.}, journal = {Biotechnology for biofuels}, volume = {11}, number = {}, pages = {121}, pmid = {29713380}, issn = {1754-6834}, abstract = {BACKGROUND: Bioelectrochemical systems (BESs) harness electrons from microbial respiration to generate power or chemical products from a variety of organic feedstocks, including lignocellulosic biomass, fermentation byproducts, and wastewater sludge. In some BESs, such as microbial fuel cells (MFCs), bacteria living in a biofilm use the anode as an electron acceptor for electrons harvested from organic materials such as lignocellulosic biomass or waste byproducts, generating energy that may be used by humans. Many BES applications use bacterial biofilm communities, but no studies have investigated protein expression by the anode biofilm community as a whole.

RESULTS: To discover functional protein expression during current generation that may be useful for MFC optimization, a label-free meta-proteomics approach was used to compare protein expression in acetate-fed anode biofilms before and after the onset of robust electricity generation. Meta-proteomic comparisons were integrated with 16S rRNA gene-based community analysis at four developmental stages. The community composition shifted from dominance by aerobic Gammaproteobacteria (90.9 ± 3.3%) during initial biofilm formation to dominance by Deltaproteobacteria, particularly Geobacter (68.7 ± 3.6%) in mature, electricity-generating anodes. Community diversity in the intermediate stage, just after robust current generation began, was double that at the early stage and nearly double that of mature anode communities. Maximum current densities at the intermediate stage, however, were relatively similar (~ 83%) to those achieved by mature-stage biofilms. Meta-proteomic analysis, correlated with population changes, revealed significant enrichment of categories specific to membrane and transport functions among proteins from electricity-producing biofilms. Proteins detected only in electricity-producing biofilms were associated with gluconeogenesis, the glyoxylate cycle, and fatty acid β-oxidation, as well as with denitrification and competitive inhibition.

CONCLUSIONS: The results demonstrate that it is possible for an MFC microbial community to generate robust current densities while exhibiting high taxonomic diversity. Moreover, these data provide evidence to suggest that startup growth of air-cathode MFCs under conditions that promote the establishment of aerobic-anaerobic syntrophy may decrease startup times. This study represents the first investigation into protein expression of a complex BES anode biofilm community as a whole. The findings contribute to understanding of the molecular mechanisms at work during BES startup and suggest options for improvement of BES generation of bioelectricity from renewable biomass.}, } @article {pmid29713285, year = {2018}, author = {Li, YH and Zhou, YH and Ren, YZ and Xu, CG and Liu, X and Liu, B and Chen, JQ and Ding, WY and Zhao, YL and Yang, YB and Wang, S and Liu, D}, title = {Inhibition of Streptococcus suis Adhesion and Biofilm Formation in Vitro by Water Extracts of Rhizoma Coptidis.}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {371}, pmid = {29713285}, issn = {1663-9812}, abstract = {Streptococcus suis is difficult to treat and responsible for various infections in humans and pigs. It can also form biofilms and induce persistent infections. Rhizoma Coptidis is a medicinal plant widely used in Traditional Chinese Medicine. Although the inhibitory effects of Rhizoma Coptidis on biofilm formation have been investigated in several studies, the ability of Rhizoma Coptidis to inhibit S. suis biofilm formation and the underlying mechanisms have not yet been reported. In this study, we showed that sub-minimal inhibitory concentrations (25 and 50 μg mL[-1]) of water extracts of Rhizoma Coptidis (Coptis deltoidea C.Y.Cheng & P.K.Hsiao, obtained from Sichuan Province) were sufficient to inhibit biofilm formation, as shown in the tissue culture plate (TCP) method and scanning electron microscopy. Real-time PCR and iTRAQ were used to measure gene and protein expression in S. suis. Sub-minimum inhibitory concentrations (25 and 50 μg mL[-1]) of Rhizoma Coptidis water extracts inhibited S. suis adhesion significantly in an anti-adherence assay. Some genes, such as gapdh, sly, and mrp, and proteins, such as antigen-like protein, CPS16V, and methyltransferase H, involved in adhesion were significantly modulated in cells treated with 50 μg mL[-1] of Rhizoma Coptidis water extracts compared to untreated cells. The results from this study suggest that compounds in Rhizoma Coptidis water extracts play an important role in inhibiting adhesion of S. suis cells and, therefore, biofilm formation.}, } @article {pmid29712730, year = {2018}, author = {Willsey, GG and Ventrone, S and Schutz, KC and Wallace, AM and Ribis, JW and Suratt, BT and Wargo, MJ}, title = {Pulmonary Surfactant Promotes Virulence Gene Expression and Biofilm Formation in Klebsiella pneumoniae.}, journal = {Infection and immunity}, volume = {86}, number = {7}, pages = {}, pmid = {29712730}, issn = {1098-5522}, support = {P20 RR021905/RR/NCRR NIH HHS/United States ; T32 HL076122/HL/NHLBI NIH HHS/United States ; R01 AI103003/AI/NIAID NIH HHS/United States ; R03 AI117069/AI/NIAID NIH HHS/United States ; P30 GM118228/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acids, Branched-Chain/biosynthesis ; Animals ; Biofilms/*drug effects ; Biogenic Polyamines/physiology ; Fimbriae, Bacterial/physiology ; Gene Expression Regulation, Bacterial/drug effects ; Host-Pathogen Interactions ; Klebsiella pneumoniae/*drug effects/pathogenicity/physiology ; Male ; Mice ; Mice, Inbred C57BL ; Pulmonary Surfactants/*pharmacology ; Virulence/genetics ; }, abstract = {The interactions between Klebsiella pneumoniae and the host environment at the site of infection are largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional response of K. pneumoniae MGH 78578 to purified pulmonary surfactant. This work revealed changes within the K. pneumoniae transcriptome that likely contribute to host colonization, adaptation, and virulence in vivo Notable transcripts expressed under these conditions include genes involved in capsule synthesis, lipopolysaccharide modification, antibiotic resistance, biofilm formation, and metabolism. In addition, we tested the contributions of other surfactant-induced transcripts to K. pneumoniae survival using engineered isogenic KPPR1 deletion strains in a murine model of acute pneumonia. In these infection studies, we identified the MdtJI polyamine efflux pump and the ProU glycine betaine ABC transporter to be significant mediators of K. pneumoniae survival within the lung and confirmed previous evidence for the importance of de novo leucine synthesis to bacterial survival during infection. Finally, we determined that pulmonary surfactant promoted type 3 fimbria-mediated biofilm formation in K. pneumoniae and identified two surfactant constituents, phosphatidylcholine and cholesterol, that drive this response. This study provides novel insight into the interactions occurring between K. pneumoniae and the host at an important infection site and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactions in vitro.}, } @article {pmid29710773, year = {2018}, author = {Carneiro, FC and Weber, SS and Silva, ON and Jacobowski, AC and Ramada, MHS and Macedo, MLR and Franco, OL and Parachin, NS}, title = {Recombinant Inga Laurina Trypsin Inhibitor (ILTI) Production in Komagataella Phaffii Confirms Its Potential Anti-Biofilm Effect and Reveals an Anti-Tumoral Activity.}, journal = {Microorganisms}, volume = {6}, number = {2}, pages = {}, pmid = {29710773}, issn = {2076-2607}, abstract = {Protease inhibitors have a broad biotechnological application ranging from medical drugs to anti-microbial agents. The Inga laurina trypsin inhibitor (ILTI) previously showed a great in vitro inhibitory effect under the adherence of Staphylococcus species, being a strong candidate for use as an anti-biofilm agent. Nevertheless, this is found in small quantities in its sources, which impairs its utilization at an industrial scale. Within this context, heterologous production using recombinant microorganisms is one of the best options to scale up the recombinant protein production. Thus, this work aimed at utilizing Komagataella phaffii to produce recombinant ILTI. For this, the vector pPIC9K+ILTI was constructed and inserted into the genome of the yeast K. phaffii, strain GS115. The protein expression was highest after 48 h using methanol 1%. A matrix-assisted laser desorption ionization[-]time-of-flight (MALDI[-]TOF) analysis was performed to confirm the production of the recombinant ILTI and its activity was investigated trough inhibitory assays using the synthetic substrate Nα-Benzoyl-D,L-arginine p-nitroanilide hydrochloride (BAPNA). Finally, recombinant ILTI (rILTI) was used in assays, showing that there was no significant difference between native and recombinant ILTI in its inhibitory activity in biofilm formation. Anti-tumor assay against Ehrlich ascites tumor (EAT) cells showed that rILTI has a potential anti-tumoral effect, showing the same effect as Melittin when incubated for 48 h in concentrations above 25 µg/mL. All together the results suggests broad applications for rILTI.}, } @article {pmid29709604, year = {2018}, author = {Bolhari, B and Pourhajibagher, M and Bazarjani, F and Chiniforush, N and Rad, MR and Pirmoazen, S and Bahador, A}, title = {Ex vivo assessment of synergic effect of chlorhexidine for enhancing antimicrobial photodynamic therapy efficiency on expression patterns of biofilm-associated genes of Enterococcus faecalis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {22}, number = {}, pages = {227-232}, doi = {10.1016/j.pdpdt.2018.04.019}, pmid = {29709604}, issn = {1873-1597}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Antigens, Bacterial/drug effects ; Bacterial Proteins/drug effects ; Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; Drug Therapy, Combination ; Enterococcus faecalis/*drug effects/genetics ; Gene Expression ; Humans ; Indocyanine Green/*pharmacology ; Lasers, Semiconductor ; Molar/drug effects/microbiology ; Photochemotherapy/methods ; Photosensitizing Agents/*pharmacology ; }, abstract = {BACKGROUND: It has clearly been demonstrated that Enterococcus faecalis, as a persistent microorganism, is the major agent in the etiopatogeny of endodontic infections. Recently, the limitations of conventional endodontic therapy have given rise to many attempts to introduce antimicrobial photodynamic therapy (aPDT) as an alternative treatment. The aim of this study was to analyze the ex vivo effect of aPDT in combination with 2.0% chlorhexidine (CHX) as a conventional therapy on colony count and expression patterns of genes associated with biofilm formation of E. faecalis.

MATERIALS AND METHODS: A total of 125 extracted human single-rooted teeth were divide into six groups (A-F; n = 20) and were incubated with E. faecalis. Group A- photosensitizer (indocyanine green [ICG]); B- diode laser; C- aPDT; D- 2.0% CHX; E- aPDT with photosensitizer modified by 2.0% CHX; and F- control group (no procedure was performed). Five remaining teeth were used to confirm the presence of E. faecalis biofilm via scanning electron microscope. Counts of colony forming units (CFUs) in each group were evaluated separately and quantitative real-time PCR (qRT-PCR) was then applied to monitor genes expression of fsrC, efa, and gelE involved in E. faecalis biofilm.

RESULTS: The results showed that none of the tested groups achieved eradication or inhibition of biofilm. On the other hand, aPDT + 2.0% CHX, 2.0% CHX, and ICG- mediated aPDT groups showed significantly less CFU/mL than ICG and diode laser groups. The group with the lowest CFU/mL count was the aPDT + 2.0% CHX, being statistically different from all other groups that could decrease the expression levels of efa, gelE, and fsrC genes 6.8-, 8.3-, and 12.1-fold, respectively.

CONCLUSION: Based on the results, the synergism effect of ICG-aPDT with 2.0% CHX leads to modulation of the virulence of E. faecalis strains biofilm model by suppressing the expression of the genes associated with biofilm formation.}, } @article {pmid29708549, year = {2018}, author = {Zhao, KQ and Wu, Y and Yi, YX and Feng, SJ and Wei, RY and Ma, Y and Zheng, CQ and Qu, D}, title = {An In Vitro Model to Study the Effect of 5-Aminolevulinic Acid-mediated Photodynamic Therapy on Staphylococcus aureus Biofilm.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {134}, pages = {}, pmid = {29708549}, issn = {1940-087X}, mesh = {Aminolevulinic Acid/*pharmacology ; Biofilms/*drug effects ; Humans ; Photochemotherapy/*methods ; Staphylococcus aureus/*drug effects/*physiology ; }, abstract = {Staphylococcus aureus (S. aureus) is a common human pathogen, which causes pyogenic and systemic infections. S. aureus infections are difficult to eradicate not only due to the emergence of antibiotic-resistant strains but also its ability to form biofilms. Recently, photodynamic therapy (PDT) has been indicated as one of the potential treatments for controlling biofilm infections. However, further studies are required to improve our knowledge of its effect on bacterial biofilms, as well as the underlying mechanisms. This manuscript describes an in vitro model of PDT with 5-aminolevulinic acid (5-ALA), a precursor of the actual photosensitizer, protoporphyrin IX (PpIX). Briefly, mature S. aureus biofilms were incubated with ALA and then exposed to light. Subsequently, the antibacterial effect of ALA-PDT on S. aureus biofilm was quantified by calculating the colony forming units (CFUs) and visualized by viability fluorescent staining via confocal laser scanning microscopy (CLSM). Representative results demonstrated a strong antibacterial effect of ALA-PDT on S. aureus biofilms. This protocol is simple and can be used to develop an in vitro model to study the treatment of S. aureus biofilms with ALA-PDT. In the future, it could also be referenced in PDT studies utilizing other photosensitizers for different bacterial strains with minimal adjustments.}, } @article {pmid29707459, year = {2018}, author = {Brown, T}, title = {Surface Areas of Textured Breast Implants: Implications for the Biofilm Theory of Capsule Formation.}, journal = {Plastic and reconstructive surgery. Global open}, volume = {6}, number = {3}, pages = {e1700}, pmid = {29707459}, issn = {2169-7574}, abstract = {BACKGROUND: Increased surface area of mammary implants is suggested as a causative agent for the development of biofilms, which may lead to capsular contraction. The aim of this study was to quantify the surface areas of round implants of different textures and examine how these data can be interpreted with regard to clinical observation.

METHODS: Surface areas of textured round breast implants were calculated from previously reported confocal scanning microscopic assessment, and dimensions sourced from 3 breast implant manufacturers (McGhan, Mentor, and Silimed). Statistical comparisons were made between manufacturers for different implant volumes, profiles, and texturing.

RESULTS: There was a difference in surface area between manufacturers for all implant profiles and between manufacturers for equivalent volume implants (F (3, 253) = 2,828.87; P < 0.001). Silimed polyurethane implants (mean area = 6.12 × 10[6] mm[2]) was the highest. Natrelle (mean area = 1.2 × 10[6] mm[2]) was the next highest, followed by Siltex (mean area = 4.8 × 10[5] mm[2]). Mentor smooth implants (mean area = 4 × 10[4] mm[2]) had the lowest mean surface area. There were no differences in surface area between the different profiles for Siltex, Silimed polyurethane, and Mentor smooth implants of the same volume.

CONCLUSIONS: The increased surface area produced by texturing, although different between manufacturers, seems to provide protection against capsular contraction. Correlation with clinical data indicates that the surface area alone cannot account for these differences. Smooth implants, which have the smallest surface area have the highest incidence of capsular contraction. These data are at odds with the biofilm theory of capsular contraction.}, } @article {pmid29707436, year = {2018}, author = {Geoffroy, V and Payette, G and Mauffrey, F and Lestin, L and Constant, P and Villemur, R}, title = {Strain-level genetic diversity of Methylophaga nitratireducenticrescens confers plasticity to denitrification capacity in a methylotrophic marine denitrifying biofilm.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e4679}, pmid = {29707436}, issn = {2167-8359}, abstract = {BACKGROUND: The biofilm of a methanol-fed, fluidized denitrification system treating a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans NL23 and Methylophaga nitratireducenticrescens JAM1 are the principal bacteria involved in the denitrifying activities. Strain NL23 can carry complete nitrate (NO[Formula: see text]) reduction to N2, whereas strain JAM1 can perform 3 out of the 4 reduction steps. A small proportion of other denitrifiers exists in the biofilm, suggesting the potential plasticity of the biofilm in adapting to environmental changes. Here, we report the acclimation of the denitrifying biofilm from continuous operating mode to batch operating mode, and the isolation and characterization from the acclimated biofilm of a new denitrifying bacterial strain, named GP59.

METHODS: The denitrifying biofilm was batch-cultured under anoxic conditions. The acclimated biofilm was plated on Methylophaga specific medium to isolate denitrifying Methylophaga isolates. Planktonic cultures of strains GP59 and JAM1 were performed, and the growth and the dynamics of NO[Formula: see text], nitrite (NO[Formula: see text]) and N2O were determined. The genomes of strains GP59 and JAM1 were sequenced and compared. The transcriptomes of strains GP59 and JAM1 were derived from anoxic cultures.

RESULTS: During batch cultures of the biofilm, we observed the disappearance of H. nitrativorans NL23 without affecting the denitrification performance. From the acclimated biofilm, we isolated strain GP59 that can perform, like H. nitrativorans NL23, the complete denitrification pathway. The GP59 cell concentration in the acclimated biofilm was 2-3 orders of magnitude higher than M. nitratireducenticrescens JAM1 and H. nitrativorans NL23. Genome analyses revealed that strain GP59 belongs to the species M. nitratireducenticrescens. The GP59 genome shares more than 85% of its coding sequences with those of strain JAM1. Based on transcriptomic analyses of anoxic cultures, most of these common genes in strain GP59 were expressed at similar level than their counterparts in strain JAM1. In contrast to strain JAM1, strain GP59 cannot reduce NO[Formula: see text] under oxic culture conditions, and has a 24-h lag time before growth and NO[Formula: see text] reduction start to occur in anoxic cultures, suggesting that both strains regulate differently the expression of their denitrification genes. Strain GP59 has the ability to reduce NO[Formula: see text] as it carries a gene encoding a NirK-type NO[Formula: see text] reductase. Based on the CRISPR sequences, strain GP59 did not emerge from strain JAM1 during the biofilm batch cultures but rather was present in the original biofilm and was enriched during this process.

DISCUSSION: These results reinforce the unique trait of the species M. nitratireducenticrescens among the Methylophaga genus as facultative anaerobic bacterium. These findings also showed the plasticity of denitrifying population of the biofilm in adapting to anoxic marine environments of the bioreactor.}, } @article {pmid29704397, year = {2018}, author = {Kurakado, S and Arai, R and Sugita, T}, title = {Association of the hypha-related protein Pra1 and zinc transporter Zrt1 with biofilm formation by the pathogenic yeast Candida albicans.}, journal = {Microbiology and immunology}, volume = {62}, number = {6}, pages = {405-410}, doi = {10.1111/1348-0421.12596}, pmid = {29704397}, issn = {1348-0421}, mesh = {Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*metabolism/pathogenicity ; Carrier Proteins/genetics/*metabolism ; Fungal Proteins/genetics/*metabolism ; Gene Expression Profiling ; Homeostasis ; Hyphae/growth & development/*metabolism ; Mutation ; Phenotype ; Zinc/metabolism/pharmacology ; }, abstract = {Bloodstream infection by the pathogenic fungus Candida albicans is a major health problem. Candidemia is often associated with medical devices, which can act as substrates for biofilm development. Biofilm-related infections are relatively difficult to treat because of their resistance to antimicrobial agents. It is therefore important to explore the mechanisms of biofilm formation. Dimorphism is a major contributor to biofilm formation in C. albicans. To determine whether the hypha-related proteins Pra1 (pH-regulated antigen) and Zrt1 (zinc transporter) are responsible for biofilm formation, the ability of pra1 and zrt1 deletion mutants to form biofilms was investigated. Biofilm formation by both deletion mutants was less than that of the wild-type strain. Because Pra1 and Zrt1 are also related to the zinc homeostasis system, the effects of adding zinc on biofilm formation were also examined. Biofilm formation was increased in the presence of zinc. These data suggest that Pra1 and Zrt1 regulate biofilm formation through zinc homeostasis.}, } @article {pmid29701307, year = {2019}, author = {Hobby, CR and Herndon, JL and Morrow, CA and Peters, RE and Symes, SJK and Giles, DK}, title = {Exogenous fatty acids alter phospholipid composition, membrane permeability, capacity for biofilm formation, and antimicrobial peptide susceptibility in Klebsiella pneumoniae.}, journal = {MicrobiologyOpen}, volume = {8}, number = {2}, pages = {e00635}, pmid = {29701307}, issn = {2045-8827}, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*growth & development ; Cell Membrane/*chemistry/drug effects/physiology ; Chromatography, Liquid ; Chromatography, Thin Layer ; Fatty Acids, Unsaturated/*metabolism ; Klebsiella pneumoniae/chemistry/*drug effects/metabolism/physiology ; Mass Spectrometry ; Microbial Sensitivity Tests ; Permeability/drug effects ; Phospholipids/*analysis ; }, abstract = {Klebsiella pneumoniae represents a major threat to human health due to a combination of its nosocomial emergence and a propensity for acquiring antibiotic resistance. Dissemination of the bacteria from its native intestinal location creates severe, complicated infections that are particularly problematic in healthcare settings. Thus, there is an urgency for identifying novel treatment regimens as the incidence of highly antibiotic-resistant bacteria rises. Recent findings have highlighted the ability of some Gram-negative bacteria to utilize exogenous fatty acids in ways that modify membrane phospholipids and influence virulence phenotypes, such as biofilm formation and antibiotic resistance. This study explores the ability of K. pneumoniae to assimilate and respond to exogenous fatty acids. The combination of thin-layer chromatography liquid chromatography-mass spectrometry confirmed adoption of numerous exogenous polyunsaturated fatty acids (PUFAs) into the phospholipid species of K. pneumoniae. Membrane permeability was variably affected as determined by two dye uptake assays. Furthermore, the availability of many PUFAs lowered the MICs to the antimicrobial peptides polymyxin B and colistin. Biofilm formation was significantly affected depending upon the supplemented fatty acid.}, } @article {pmid29698916, year = {2018}, author = {Wang, X and Bi, X and Hem, LJ and Ratnaweera, H}, title = {Microbial community composition of a multi-stage moving bed biofilm reactor and its interaction with kinetic model parameters estimation.}, journal = {Journal of environmental management}, volume = {218}, number = {}, pages = {340-347}, doi = {10.1016/j.jenvman.2018.04.015}, pmid = {29698916}, issn = {1095-8630}, mesh = {*Biofilms ; Biomass ; *Bioreactors ; Kinetics ; Wastewater ; }, abstract = {Microbial community diversity determines the function of each chamber of multi-stage moving bed biofilm reactor (MBBR) systems. How the microbial community data can be further used to serve wastewater treatment process modelling and optimization has been rarely studied. In this study, a MBBR system was set up to investigate the microbial community diversity of biofilm in each functional chamber. The compositions of microbial community of biofilm from different chambers of MBBR were quantified by high-throughput sequencing. Significantly higher proportion of autotrophs were found in the second aerobic chamber (15.4%), while 4.3% autotrophs were found in the first aerobic chamber. Autotrophs in anoxic chamber were negligible. Moreover, ratios of active heterotrophic biomass and autotrophic biomass (XH/XA) were obtained by performing respiration tests. By setting heterotroph/autotroph ratios obtained from sequencing analysis equal to XH/XA, a novel approach for kinetic model parameters estimation was developed. This work not only investigated microbial community of MBBR system, but also it provided an approach to make further use of molecular microbiology analysis results.}, } @article {pmid29698826, year = {2018}, author = {Divya, S and Thinesh, T and Seghal Kiran, G and Hassan, S and Selvin, J}, title = {Emergence of a multi host biofilm forming opportunistic pathogen Staphylococcus sciuri D26 in coral Favites abdita.}, journal = {Microbial pathogenesis}, volume = {120}, number = {}, pages = {204-212}, doi = {10.1016/j.micpath.2018.04.037}, pmid = {29698826}, issn = {1096-1208}, mesh = {Animals ; Anthozoa/immunology/*microbiology ; Biofilms/*growth & development ; Coral Reefs ; Ecosystem ; India ; Melanins/metabolism ; Monophenol Monooxygenase ; Phylogeny ; Salinity ; Staphylococcus/classification/isolation & purification/*pathogenicity/*physiology ; Stress, Physiological ; Ultraviolet Rays ; Virulence ; Virulence Factors ; Water Pollution ; }, abstract = {Corals are hotspots of ocean microbial diversity and imbalance in the composition of coral associated microbes has been mostly correlated with the emergence of climate change driven diseases which affect the overall stability of the reef ecosystem. Coral sampling was performed by SCUBA diving at Palk Bay (latitude 9.271580, longitude 79.132203) south Indian coast. Among the 54 bacterial isolates, an isolate MGL-D26 showed comparatively high biofilm formation and was identified as Staphylococcus sciuri based on phylogenetic analysis. The production of exopolysaccharide (EPS) confirmed the formation of a slimy EPS matrix associated with the biofilm. The biofilm formation in S. sciuri D26 was induced significantly by UV exposure followed by other stress factors including pollution, agitation, and salinity. The strain inhibited innate immune factors of corals such as melanin synthesis and phenoloxidase. Challenge experiments in a model organism Aiptasia sp. showed pathogenicity of S. sciuri. Histopathological analysis revealed tissue invasion by S. sciuri which was a predisposing factor leading to mortality in challenged Aiptasia sp. However, specific disease condition of corals infected by S. sciuri requires continuous field monitoring and further investigation. Based on the findings, S. sciuri was a first reported multi-host opportunistic pathogen which has emerged in corals under environmental stress.}, } @article {pmid29698774, year = {2018}, author = {Nadaf, NH and Parulekar, RS and Patil, RS and Gade, TK and Momin, AA and Waghmare, SR and Dhanavade, MJ and Arvindekar, AU and Sonawane, KD}, title = {Biofilm inhibition mechanism from extract of Hymenocallis littoralis leaves.}, journal = {Journal of ethnopharmacology}, volume = {222}, number = {}, pages = {121-132}, doi = {10.1016/j.jep.2018.04.031}, pmid = {29698774}, issn = {1872-7573}, mesh = {Adhesins, Bacterial/metabolism ; *Amaryllidaceae ; Aminoacyltransferases/metabolism ; Animals ; Anti-Infective Agents/analysis/*pharmacology ; Antioxidants/analysis/pharmacology ; Bacteria/*drug effects/growth & development ; Bacterial Physiological Phenomena/*drug effects ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development/physiology ; Cysteine Endopeptidases/metabolism ; Fungal Proteins/metabolism ; Male ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Molecular Docking Simulation ; Phytochemicals/analysis/pharmacology ; Plant Extracts/analysis/*pharmacology ; Plant Leaves ; Rats, Wistar ; Skin/drug effects ; }, abstract = {Hymenocallis littoralis (Jacq.) Salisb. has been referred as beach spider lily and commonly known for its rich phytochemical diversity. Phytochemicals such as alkaloids, volatile constituents, phenols, flavonoids, flavonols extracted from different parts of these plants like bulbs, flowers, leaf, stem and root had been used in folk medicines from ancient times because of their excellent antimicrobial and antioxidant properties. The leaf and bulb extract of H. littoralis plant was traditionally used for wound healing. Alkaloids extracted from bulb of this plant possess anti-viral, anti-neoplastic and cytotoxic properties. However, these phytochemicals have also shown antibiofilm activity, which is considered as one of the important factor accountable for the drug resistance in microorganisms. Thus, the investigation of medicinal properties of H. littoralis could be useful to control biofilm producing pathogens.

AIM OF THE STUDY: Explore antimicrobial, antibiofilm and antioxidant potentials of H. littoralis against pathogenic microorganisms using experimental and computational biology approach.

MATERIALS AND METHODS: Phytochemical extraction from dried powder of H. littoralis leaves was done by solvent extraction using methanol. Antimicrobial and antibiofilm activities of leaves extract were carried out using agar well diffusion method, growth curve, minimum inhibitory concentration (MIC) and Scanning Electron Microscopy (SEM). Liquid Chromatography and Mass Spectroscopy (LCMS) technique was used for the identification of phytochemicals. Molecular docking studies of antibiofilm agents with adhesin proteins were performed using Autodock 4.2. Antioxidant activity of extract was carried out by FRAP assay. The noxious effect of extract was investigated by histological studies on rat skin.

RESULTS: The preliminary phytochemical analysis of methanolic leaves extract revealed the presence of alkaloids, flavonoids, terpenoid, glycosides, terpene, terpenoids and phenolics. The various phytochemicals such as Apigenin 7-(4'', 6'' diacetylalloside)-4'- alloside, Catechin 7-O- apiofuranoside, Emodic acid, Epicatechin 3-O- β-D-glucopyranoside, 4 - Methylesculetin, Methylisoeugenol, Quercetin 5,7,3',4'-tetramethyl ether 3-rutinoside, 4 - Methylumbelliferyl β-D- glucuronide were extracted, characterized and recognized from the leaves extract of H. littoralis. The identification of these phytochemicals was performed using LC-MS. The antimicrobial property of H. littoralis leaf extract was investigated against different pathogenic microorganisms. Out of these tested microorganisms, promising antibiofilm and antimicrobial activities were confirmed against S. aureus NCIM 2654 and C. albicans NCIM 3466 by using growth curve and SEM analysis. MIC of this leaf extract was identified as 45 µg/ml and 70 µg/ml for S. aureus NCIM 2654 and C. albicans NCIM 3466 respectively. The leaves extract also showed good antioxidant activity due to presence of phenols and flavonoids. Molecular docking of these identified antibiofilm components interacts with the active site residues of adhesin proteins, Sortase A and Als3 from S. aureus and C. albicans respectively. Histological studies of extracted phytochemicals revealed non-noxious effects on rat skin.

CONCLUSION: Thus, the present study revealed that the leaves extract of H. littoralis contains various phytochemicals having good extent of antimicrobial, antibiofilm and antioxidant properties. The in-vitro and in-silico results would be useful to design new lead compounds against biofilm producing pathogenic microorganisms.}, } @article {pmid29698215, year = {2017}, author = {Shokoohi, R and Torkshavand, Z and Zolghadnasab, H and Alikhani, MY and Hemmat, MS}, title = {Study of the efficiency of moving bed biofilm reactor (MBBR) in LAS Anionic Detergent removal from hospital wastewater: determination of removing model according to response surface methodology (RSM).}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {2017}, number = {1}, pages = {1-7}, doi = {10.2166/wst.2018.014}, pmid = {29698215}, issn = {0273-1223}, mesh = {Alkanesulfonic Acids ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Detergents/*chemistry ; Medical Waste ; Medical Waste Disposal ; Models, Theoretical ; Waste Disposal, Fluid/*methods ; *Wastewater ; Water Pollutants ; }, abstract = {Detergents are considered one of the important pollutants in hospital wastewater. Achieving efficient and bio-friendly methods for the removal of these pollutants is considered as a concern for environmental researchers. This study aims at studying the efficiency of a moving bed biofilm reactor (MBBR) system for removing linear alkyl benzene sulfonate (LAS) from hospital wastewater with utilization of response surface methodology (RSM). The present study was carried out on a reactor with continuous hydraulic flow using media k1 at pilot scale to remove detergent from hospital wastewater. The effect of independent variables including contact time, percentage of media filling and mixed liquor suspended solids (MLSS) concentration of 1000-3000 mg/l on the system efficiency were assessed. Methylene blue active substances (MBAS) and chemical oxygen demand (COD) 750-850 mg/l were used by closed laboratory method in order to measure the concentration of LAS. The results revealed that the removal efficiency of LAS detergent and COD using media k1, retention time of 24 hours, and MLSS concentration of around 3,000 mg/l were 92.3 and 95.8%, respectively. The results showed that the MBBR system as a bio-friendly compatible method has high efficiency in removing detergents from hospital wastewater and can achieve standard output effluent in acceptable time.}, } @article {pmid29695043, year = {2018}, author = {Desriac, F and Clamens, T and Rosay, T and Rodrigues, S and Tahrioui, A and Enault, J and Roquigny, L and Racine, PJ and Taupin, L and Bazire, A and Dufour, A and Leprince, J and Bouffartigues, E and Chevalier, S and Feuilloley, MGJ and Lesouhaitier, O}, title = {Different Dose-Dependent Modes of Action of C-Type Natriuretic Peptide on Pseudomonas aeruginosa Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {7}, number = {2}, pages = {}, pmid = {29695043}, issn = {2076-0817}, abstract = {We have previously shown that the C-type Natriuretic Peptide (CNP), a peptide produced by lungs, is able to impact Pseudomonasaeruginosa physiology. In the present work, the effect of CNP at different concentrations on P. aeruginosa biofilm formation was studied and the mechanisms of action of this human hormone on P. aeruginosa were deciphered. CNP was shown to inhibit dynamic biofilm formation in a dose-dependent manner without affecting the bacterial growth at any tested concentrations. The most effective concentrations were 1 and 0.1 µM. At 0.1 µM, the biofilm formation inhibition was fully dependent on the CNP sensor protein AmiC, whereas it was only partially AmiC-dependent at 1 µM, revealing the existence of a second AmiC-independent mode of action of CNP on P. aeruginosa. At 1 µM, CNP reduced both P. aeruginosa adhesion on glass and di-rhamnolipid production and also increased the bacterial membrane fluidity. The various effects of CNP at 1 µM and 0.1 µM on P. aeruginosa shown here should have major consequences to design drugs for biofilm treatment or prevention.}, } @article {pmid29693330, year = {2018}, author = {Molenaar, SD and Sleutels, T and Pereira, J and Iorio, M and Borsje, C and Zamudio, JA and Fabregat-Santiago, F and Buisman, CJN and Ter Heijne, A}, title = {In situ Biofilm Quantification in Bioelectrochemical Systems by using Optical Coherence Tomography.}, journal = {ChemSusChem}, volume = {11}, number = {13}, pages = {2171-2178}, pmid = {29693330}, issn = {1864-564X}, abstract = {Detailed studies of microbial growth in bioelectrochemical systems (BESs) are required for their suitable design and operation. Here, we report the use of optical coherence tomography (OCT) as a tool for in situ and noninvasive quantification of biofilm growth on electrodes (bioanodes). An experimental platform is designed and described in which transparent electrodes are used to allow real-time, 3D biofilm imaging. The accuracy and precision of the developed method is assessed by relating the OCT results to well-established standards for biofilm quantification (chemical oxygen demand (COD) and total N content) and show high correspondence to these standards. Biofilm thickness observed by OCT ranged between 3 and 90 μm for experimental durations ranging from 1 to 24 days. This translated to growth yields between 38 and 42 mgCODbiomass gCODacetate [-1] at an anode potential of -0.35 V versus Ag/AgCl. Time-lapse observations of an experimental run performed in duplicate show high reproducibility in obtained microbial growth yield by the developed method. As such, we identify OCT as a powerful tool for conducting in-depth characterizations of microbial growth dynamics in BESs. Additionally, the presented platform allows concomitant application of this method with various optical and electrochemical techniques.}, } @article {pmid29691368, year = {2018}, author = {Liu, H and Shang, W and Hu, Z and Zheng, Y and Yuan, J and Hu, Q and Peng, H and Cai, X and Tan, L and Li, S and Zhu, J and Li, M and Hu, X and Zhou, R and Rao, X and Yang, Y}, title = {A novel SigB(Q225P) mutation in Staphylococcus aureus retains virulence but promotes biofilm formation.}, journal = {Emerging microbes & infections}, volume = {7}, number = {1}, pages = {72}, pmid = {29691368}, issn = {2222-1751}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Humans ; Micrococcal Nuclease/genetics ; *Mutation ; Phenotype ; Promoter Regions, Genetic ; Real-Time Polymerase Chain Reaction ; Sigma Factor/*genetics ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*genetics/*pathogenicity ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus is an important pathogen that produces abundant virulence factors, which cause various diseases that burden human health worldwide. The stress response regulon called sigma factor B (SigB) is a well-characterized global regulator that is involved in the regulation of S. aureus virulence, pigmentation, and biofilm formation. However, the regulatory network upon SigB in S. aureus is incompletely described. Here, we identified a novel substitution mutation, SigB(Q225P), which contributed the nonpigmented phenotype of S. aureus. The S. aureus mutant carrying SigB(Q225P) substitution lacks staphyloxanthin, a key virulence factor in protecting bacteria from host-oxidant killing, but retains bacterial pathogenicity with pleiotropic alterations in virulence factors, resulting in similar lethality and abscess formation ability in animal models. We also reported the SigB(Q225P) promotion of biofilm formation in S. aureus. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that the expression of nuc gene, which encodes thermonuclease, was significantly downregulated, resulting in accumulation of eDNA in the biofilm of SigB(Q225P) mutant strain. LacZ reporter assay showed that SigB(Q225P) influenced the activity of nuc promoter. Furthermore, electrophoretic mobility shift assay (EMSA) and Bio-layer interferometry (BLI) assay revealed that both SigB and SigB(Q225P) proteins could directly bind to nuc gene promoter; however, the binding activity decreased for SigB(Q225P). Our data renewed the understanding of the relationship between S. aureus golden pigment and its virulence and suggested that a single substitution mutation in SigB might enhance the biofilm formation of S. aureus by directly downregulating nuc expression.}, } @article {pmid29691334, year = {2018}, author = {Wu, C and Al Mamun, AAM and Luong, TT and Hu, B and Gu, J and Lee, JH and D'Amore, M and Das, A and Ton-That, H}, title = {Forward Genetic Dissection of Biofilm Development by Fusobacterium nucleatum: Novel Functions of Cell Division Proteins FtsX and EnvC.}, journal = {mBio}, volume = {9}, number = {2}, pages = {}, pmid = {29691334}, issn = {2150-7511}, support = {R01 DE017382/DE/NIDCR NIH HHS/United States ; R01 DE026758/DE/NIDCR NIH HHS/United States ; R21 DE026574/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; DNA Transposable Elements ; Fusobacterium nucleatum/cytology/*genetics/*growth & development ; Gene Deletion ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Mutagenesis, Insertional/methods ; Protein Interaction Maps ; }, abstract = {Fusobacterium nucleatum is a key member of the human oral biofilm. It is also implicated in preterm birth and colorectal cancer. To facilitate basic studies of fusobacterial virulence, we describe here a versatile transposon mutagenesis procedure and a pilot screen for mutants defective in biofilm formation. Out of 10 independent biofilm-defective mutants isolated, the affected genes included the homologs of the Escherichia coli cell division proteins FtsX and EnvC, the electron transport protein RnfA, and four proteins with unknown functions. Next, a facile new gene deletion method demonstrated that nonpolar, in-frame deletion of ftsX or envC produces viable bacteria that are highly filamentous due to defective cell division. Transmission electron and cryo-electron microscopy revealed that the ΔftsX and ΔenvC mutant cells remain joined with apparent constriction, and scanning electron microscopy (EM) uncovered a smooth cell surface without the microfolds present in wild-type cells. FtsX and EnvC proteins interact with each other as well as a common set of interacting partners, many with unknown function. Last, biofilm development is altered when cell division is blocked by MinC overproduction; however, unlike the phenotypes of ΔftsX and ΔenvC mutants, a weakly adherent biofilm is formed, and the wild-type rugged cell surface is maintained. Therefore, FtsX and EnvC may perform novel functions in Fusobacterium cell biology. This is the first report of an unbiased approach to uncover genetic determinants of fusobacterial biofilm development. It points to an intriguing link among cytokinesis, cell surface dynamics, and biofilm formation, whose molecular underpinnings remain to be elucidated.IMPORTANCE Little is known about the virulence mechanisms and associated factors in F. nucleatum, due mainly to the lack of convenient genetic tools for this organism. We employed two efficient genetic strategies to identify F. nucleatum biofilm-defective mutants, revealing FtsX and EnvC among seven biofilm-associated factors. Electron microscopy established cell division defects of the ΔftsX and ΔenvC mutants, accompanied with a smooth cell surface, unlike the microfold, rugged appearance of wild-type bacteria. Proteomic studies demonstrated that FtsX and EnvC interact with each other as well as a set of common and unique interacting proteins, many with unknown functions. Importantly, blocking cell division by MinC overproduction led to formation of a weakly adherent biofilm, without alteration of the wild-type cell surface. Thus, this work links cell division and surface dynamics to biofilm development and lays a foundation for future genetic and biochemical investigations of basic cellular processes in this clinically significant pathogen.}, } @article {pmid29688490, year = {2018}, author = {Gupta, P and Mankere, B and Chekkoora Keloth, S and Tuteja, U and Pandey, P and Chelvam, KT}, title = {Increased antibiotic resistance exhibited by the biofilm of Vibrio cholerae O139.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {7}, pages = {1841-1847}, doi = {10.1093/jac/dky127}, pmid = {29688490}, issn = {1460-2091}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cholera/microbiology ; Diarrhea/microbiology ; *Drug Resistance, Multiple, Bacterial ; Epidemics ; Humans ; India ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Vibrio cholerae O139/*drug effects/physiology ; }, abstract = {BACKGROUND: Vibrio cholerae, the aetiological agent of the deadly diarrhoeal disease cholera, is known to form biofilm. The antibiotic susceptibility status of biofilm of V. cholerae O139, an important epidemic strain in India and other countries, has not previously been studied in detail.

METHODS: Antibiotic susceptibility status of planktonic and biofilm cultures of V. cholerae O139 was evaluated by determining MIC, MBC and minimum biofilm eradication concentration (MBEC) values of five different classes of antibiotics using established methods. Effects of antibiotic treatment on planktonic and biofilm cultures were analysed by scanning electron microscopy. The virulence of the antibiotic-surviving population (ASP) was evaluated using an infant mouse model. The frequency of spontaneous mutants and inheritability of antibiotic resistance were determined with standard methods.

RESULTS: The antibiotic resistance exhibited by biofilm of V. cholerae O139 was found to be significantly higher (P < 0.05) than its planktonic counterpart. The biofilm-associated antibiotic resistance was found to be transient and exclusive to the biofilm culture. The frequency of ASP clones among antibiotic-treated biofilm cultures occurred at a rate of 0.012%-0.95% and these clones were found to retain the virulence and antibiotic resistance of their parent strains.

CONCLUSIONS: The biofilm of V. cholerae O139 was found to be resistant to different types of antibiotics tested. This unconventional biofilm resistance highlights the hidden danger of antimicrobial escape by V. cholerae, increased risk of cholera transmission and its continued persistence in the environment.}, } @article {pmid29687885, year = {2018}, author = {Alabdullatif, M and Atreya, CD and Ramirez-Arcos, S}, title = {Antimicrobial peptides: an effective approach to prevent bacterial biofilm formation in platelet concentrates.}, journal = {Transfusion}, volume = {58}, number = {8}, pages = {2013-2021}, doi = {10.1111/trf.14646}, pmid = {29687885}, issn = {1537-2995}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects ; Blood Platelets/cytology/*microbiology ; Drug Therapy, Combination ; Humans ; Peptides/chemical synthesis/*pharmacology ; Staphylococcus epidermidis/drug effects ; Transfusion Medicine ; }, abstract = {BACKGROUND: The safety of platelet concentrates (PCs) is a major concern in transfusion medicine due to contamination mainly with skin Gram-positive bacteria. The predominant contaminant, Staphylococcus epidermidis, forms bacterial cell aggregates (biofilms) in PCs posing a safety risk for transfusion patients. Combinations of synthetic antimicrobial peptides (AMPs) have demonstrated bactericidal activity in PCs. Herein, we have evaluated the ability of a mix of AMPs to inhibit biofilm formation and/or eradicate S. epidermidis biofilms.

STUDY DESIGN AND METHODS: Three synthetic AMPs, the platelet-derived peptide (PD4) and two arginine-tryptophan repeats (RW3 and RW4), were used for bactericidal and antibiofilm experiments in glucose-supplemented trypticase soy broth (TSBg) and PCs spiked with three biofilm-forming strains of S. epidermidis. Time-killing assays were performed to evaluate the bactericidal capability of the peptides. Inhibition of biofilm formation was assayed by seeding S. epidermidis into TSBg or PC cultures supplemented with the AMPs. Biofilm eradication assays were performed after AMP treatment of preformed biofilms with and without mechanical dislodging. Biofilms were measured using a crystal violet assay.

RESULTS: Time-killing assays demonstrated that all S. epidermidis strains were eliminated after 24 hours of AMP treatment. While inhibition of biofilm formation was observed for all S. epidermidis strains in TSBg and PCs, the AMP treatment was only effective to reduce the bacterial load of mechanically dislodged biofilms.

CONCLUSION: The combination of three synthetic AMPs (PD4-RW3-RW4) can be used to inhibit biofilm formation by S. epidermidis to enhance PC safety. However, further investigation is needed to improve their activity against mature S. epidermidis biofilms.}, } @article {pmid29687554, year = {2018}, author = {LeTourneau, MK and Marshall, MJ and Cliff, JB and Bonsall, RF and Dohnalkova, AC and Mavrodi, DV and Devi, SI and Mavrodi, OV and Harsh, JB and Weller, DM and Thomashow, LS}, title = {Phenazine-1-carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces.}, journal = {Environmental microbiology}, volume = {20}, number = {6}, pages = {2178-2194}, doi = {10.1111/1462-2920.14244}, pmid = {29687554}, issn = {1462-2920}, support = {2090-22000-016-07//USDA National Institute of Food and Agriculture/International ; DE-SC0014664//Oak Ridge Institute for Science and Education/International ; 60385//U.S. Department of Energy/International ; DE-AC05-76RL01830//U.S. Department of Energy/International ; }, mesh = {Biofilms/growth & development ; Biomass ; Phenazines/pharmacology ; Plant Roots/*microbiology ; Pseudomonas/*physiology ; Rhizosphere ; Soil/*chemistry ; Soil Microbiology ; Triticum/*microbiology ; }, abstract = {Phenazine-1-carboxylic acid (PCA) is produced by rhizobacteria in dryland but not in irrigated wheat fields of the Pacific Northwest, USA. PCA promotes biofilm development in bacterial cultures and bacterial colonization of wheat rhizospheres. However, its impact upon biofilm development has not been demonstrated in the rhizosphere, where biofilms influence terrestrial carbon and nitrogen cycles with ramifications for crop and soil health. Furthermore, the relationships between soil moisture and the rates of PCA biosynthesis and degradation have not been established. In this study, expression of PCA biosynthesis genes was upregulated relative to background transcription, and persistence of PCA was slightly decreased in dryland relative to irrigated wheat rhizospheres. Biofilms in dryland rhizospheres inoculated with the PCA-producing (PCA[+]) strain Pseudomonas synxantha 2-79RN10 were more robust than those in rhizospheres inoculated with an isogenic PCA-deficient (PCA[-]) mutant strain. This trend was reversed in irrigated rhizospheres. In dryland PCA[+] rhizospheres, the turnover of [15] N-labelled rhizobacterial biomass was slower than in the PCA[-] and irrigated PCA[+] treatments, and incorporation of bacterial [15] N into root cell walls was observed in multiple treatments. These results indicate that PCA promotes biofilm development in dryland rhizospheres, and likely influences crop nutrition and soil health in dryland wheat fields.}, } @article {pmid29685220, year = {2018}, author = {da Silva Duarte, V and Dias, RS and Kropinski, AM and da Silva Xavier, A and Ferro, CG and Vidigal, PMP and da Silva, CC and de Paula, SO}, title = {A T4virus prevents biofilm formation by Trueperella pyogenes.}, journal = {Veterinary microbiology}, volume = {218}, number = {}, pages = {45-51}, doi = {10.1016/j.vetmic.2018.03.025}, pmid = {29685220}, issn = {1873-2542}, mesh = {Actinomycetaceae/genetics/isolation & purification/*virology ; Actinomycetales Infections/microbiology/*veterinary ; Animals ; Bacteriophage T4/*genetics/isolation & purification/metabolism/ultrastructure ; Biofilms/*growth & development ; Cattle ; Cattle Diseases/microbiology ; Escherichia coli/isolation & purification/virology ; Female ; Mastitis/microbiology/*veterinary ; Microscopy, Electron ; Proteomics ; Virulence Factors ; }, abstract = {Trueperella pyogenes is an opportunistic pathogen of many animal species. It causes economic losses worldwide, through mastitis, metritis and mainly endometritis in dairy cows. The ability of this bacterium to form biofilms is implicated in chronic infections through hampering immune system recognition and antibiotic penetration. Since it is difficult to eradicate T. pyogenes infections with antibiotics, phage therapy presents itself as a non-toxic, effective and economically viable alternative. The present study evaluated the use of the bacteriophage vB_EcoM-UFV13 (UFV13) in the prevention of T. pyogenes biofilm development. Based upon two different approaches (crystal violet and sessile cell counting) we observed that only a multiplicity of infection (MOI) of 10 showed a statistically significant reduction in biofilm formation. Although the exact mechanisms of biofilm disruption and cell-adhesion inhibition have not been determined, genome sequence analysis of the Escherichia phage UFV13 revealed a repertoire of virion-associated peptidoglycan hydrolases (VAPGHs). The present study presents new findings regarding the disruption of biofilm formation of a Gram-positive bacterium. Subsequent transcriptomic and proteomic research will help us to understand the exact interaction mechanisms between UFV13 and T. pyogenes.}, } @article {pmid29685049, year = {2018}, author = {Šmitran, A and Vuković, D and Opavski, N and Gajić, I and Marinković, J and Božić, L and Živanović, I and Kekić, D and Popović, S and Ranin, L}, title = {Influence of subinhibitory antibiotic concentration on Streptococcus pyogenes adherence and biofilm production.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {65}, number = {2}, pages = {229-240}, doi = {10.1556/030.65.2018.026}, pmid = {29685049}, issn = {1217-8950}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*growth & development ; Microbial Sensitivity Tests ; Streptococcus pyogenes/*drug effects/physiology ; }, abstract = {In this study, the focus was on the effects of sub-MICs of the antibiotics on adherence, hydrophobicity, and biofilm formation by two groups of Streptococcus pyogenes strains, which were responsible for different clinical cases. The aim of this study was to explore the effects of sub-MICs of penicillin, ceftriaxone, erythromycin, and clindamycin on adherence, surface hydrophobicity, and biofilm biomass in two selected collections of group A streptococcus (GAS): strains isolated from carriers (CA) and strains isolated from patients with tonsillopharyngitis (TPh). Isolates were tested for hydrophobicity to xylene, adherence, and biofilm production in uncoated microtiter plates before and after treatment with 1/2 and 1/4 MICs of antibiotics. Penicillin reduced adherence and biofilm production in TPh strains, whereas ceftriaxone diminished adherence and biofilm formation in CA group. On the contrary, clindamycin enhanced adherence and biofilm production in both groups of strains. Erythromycin did not significantly alter adherence, but triggered biofilm production in both groups of isolates. Hydrophobicity of both groups of strains was significantly reduced after exposure to all antibiotics. Beta-lactams displayed anti-biofilm activity; penicillin diminished both adherence and biofilm production in TPh strains, whereas ceftriaxone reduced it in strains isolated from CA.}, } @article {pmid29684889, year = {2018}, author = {Li, C and Sun, Y and Yue, Z and Huang, M and Wang, J and Chen, X and An, X and Zang, H and Li, D and Hou, N}, title = {Combination of a recombinant bacterium with organonitrile-degrading and biofilm-forming capability and a positively charged carrier for organonitriles removal.}, journal = {Journal of hazardous materials}, volume = {353}, number = {}, pages = {372-380}, doi = {10.1016/j.jhazmat.2018.03.058}, pmid = {29684889}, issn = {1873-3336}, mesh = {Acetonitriles/*metabolism ; Acrylonitrile/*metabolism ; Amidohydrolases/genetics ; Bacillus subtilis/*physiology ; Biofilms/*growth & development ; Bioreactors ; Hydro-Lyases/genetics ; Nitriles/*metabolism ; Waste Disposal, Fluid/methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The immobilization of organonitrile-degrading bacteria via the addition of biofilm-forming bacteria represents a promising technology for the treatment of organonitrile-containing wastewater, but biofilm-forming bacteria simply mixed with degrading bacteria may reduce the biodegradation efficiency. Nitrile hydratase and amidase genes, which play critical roles in organonitriles degradation, were cloned and transformed into the biofilm-forming bacterium Bacillus subtilis N4 to construct a recombinant bacterium B. subtilis N4/pHTnha-ami. Modified polyethylene carriers with positive charge was applied to promote bacterial adherence and biofilm formation. The immobilized B. subtilis N4/pHTnha-ami was resistant to organonitriles loading shocks and could remove organic cyanide ion with a initial concentration of 392.6 mg/L for 24 h in a moving bed biofilm reactor. The imputed quorum-sensing signal and the high-throughput sequencing analysis of the biofilm indicated that B. subtilis N4/pHTnha-ami was successfully immobilized and became dominant. The successful application of the immobilized recombinant bacterium offers a novel strategy for the biodegradation of recalcitrant compounds.}, } @article {pmid29684330, year = {2018}, author = {Pizzo, E and Pane, K and Bosso, A and Landi, N and Ragucci, S and Russo, R and Gaglione, R and Torres, MDT and de la Fuente-Nunez, C and Arciello, A and Di Donato, A and Notomista, E and Di Maro, A}, title = {Novel bioactive peptides from PD-L1/2, a type 1 ribosome inactivating protein from Phytolacca dioica L. Evaluation of their antimicrobial properties and anti-biofilm activities.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1860}, number = {7}, pages = {1425-1435}, doi = {10.1016/j.bbamem.2018.04.010}, pmid = {29684330}, issn = {0005-2736}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Computational Biology ; Lipopolysaccharides/metabolism ; Phytolacca/*chemistry ; Plant Proteins/chemistry/*pharmacology ; Protein Structure, Secondary ; Ribosome Inactivating Proteins, Type 1/chemistry/*pharmacology ; }, abstract = {Antimicrobial peptides, also called Host Defence Peptides (HDPs), are effectors of innate immune response found in all living organisms. In a previous report, we have identified by chemical fragmentation, and characterized the first cryptic antimicrobial peptide in PD-L4, a type 1 ribosome inactivating protein (RIP) from leaves of Phytolacca dioica L. We applied a recently developed bioinformatic approach to a further member of the differently expressed pool of type 1 RIPs from P. dioica (PD-L1/2), and identified two novel putative cryptic HDPs in its N-terminal domain. These two peptides, here named IKY31 and IKY23, exhibit antibacterial activities against planktonic bacterial cells and, interestingly, significant anti-biofilm properties against two Gram-negative strains. Here, we describe that PD-L1/2 derived peptides are able to induce a strong dose-dependent reduction in biofilm biomass, affect biofilm thickness and, in the case of IKY31, interfere with cell-to-cell adhesion, likely by affecting biofilm structural components. In addition to these findings, we found that both PD-L1/2 derived peptides are able to assume stable helical conformations in the presence of membrane mimicking agents (SDS and TFE) and intriguingly beta structures when incubated with extracellular bacterial wall components (LPS and alginate). Overall, the data collected in this work provide further evidence of the importance of cryptic peptides derived from type 1 RIPs in host/pathogen interactions, especially under pathophysiological conditions induced by biofilm forming bacteria. This suggests a new possible role of RIPs as precursors of antimicrobial and anti-biofilm agents, likely released upon defensive proteolytic processes, which may be involved in plant homeostasis.}, } @article {pmid29684116, year = {2018}, author = {Milivojevic, D and Šumonja, N and Medic, S and Pavic, A and Moric, I and Vasiljevic, B and Senerovic, L and Nikodinovic-Runic, J}, title = {Biofilm-forming ability and infection potential of Pseudomonas aeruginosa strains isolated from animals and humans.}, journal = {Pathogens and disease}, volume = {76}, number = {4}, pages = {}, doi = {10.1093/femspd/fty041}, pmid = {29684116}, issn = {2049-632X}, mesh = {A549 Cells ; Animals ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Embryo, Nonmammalian ; Gene Expression ; Hemolysin Proteins/biosynthesis/genetics/*toxicity ; Hemolysis/drug effects ; Host Specificity ; Humans ; Machine Learning ; Pseudomonas Infections/microbiology/pathology ; Pseudomonas aeruginosa/growth & development/metabolism/*pathogenicity ; Pyocyanine/biosynthesis/genetics/*toxicity ; Virulence ; Virulence Factors/biosynthesis/genetics/*toxicity ; Zebrafish ; }, abstract = {Pseudomonas aeruginosa has been amongst the top 10 'superbugs' worldwide and is causing infections with poor outcomes in both humans and animals. From 202 P. aeruginosa isolates (n = 121 animal and n = 81 human), 40 were selected on the basis of biofilm-forming ability and were comparatively characterized in terms of virulence determinants to the type strain P. aeruginosa PAO1. Biofilm formation, pyocyanin and hemolysin production, and bacterial motility patterns were compared with the ability to kill human cell line A549 in vitro. On average, there was no significant difference between levels of animal and human cytotoxicity, while human isolates produced higher amounts of pyocyanin, hemolysins and showed increased swimming ability. Non-parametric statistical analysis identified the highest positive correlation between hemolysis and the swarming ability. For the first time an ensemble machine learning approach used on the in vitro virulence data determined the highest relative predictive importance of the submerged biofilm formation for the cytotoxicity, as an indicator of the infection ability. The findings from the in vitro study were validated in vivo using zebrafish (Danio rerio) embryos. This study highlighted no major differences between P. aeruginosa species isolated from animal and human infections and the importance of pyocyanin production in cytotoxicity and infection ability.}, } @article {pmid29682545, year = {2018}, author = {Li, B and Li, X and Lin, H and Zhou, Y}, title = {Curcumin as a Promising Antibacterial Agent: Effects on Metabolism and Biofilm Formation in S. mutans.}, journal = {BioMed research international}, volume = {2018}, number = {}, pages = {4508709}, pmid = {29682545}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Curcumin/*pharmacology ; Dental Caries/microbiology ; Microbial Sensitivity Tests/methods ; Microscopy, Confocal/methods ; Streptococcus mutans/*drug effects ; Virulence Factors/metabolism ; }, abstract = {Streptococcus mutans (S. mutans) has been proved to be the main aetiological factor in dental caries. Curcumin, a natural product, has been shown to exhibit therapeutic antibacterial activity, suggesting that curcumin may be of clinical interest. The objective of this study is to evaluate the inhibitory effects of curcumin on metabolism and biofilm formation in S. mutans using a vitro biofilm model in an artificial oral environment. S. mutans biofilms were treated with varying concentrations of curcumin. The biofilm metabolism and biofilm biomass were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and the crystal violet assay. Confocal laser scanning microscopy was used to analyse the composition and extracellular polysaccharide content of S. mutans biofilm after curcumin treatment. The biofilm structure was evaluated using a scanning electron microscope. The gene expression of virulence-related factors was assessed by real-time PCR. The antibiofilm effect of curcumin was compared with that of chlorhexidine. The sessile minimum inhibitory concentration (SMIC50%) of curcumin against S. mutans biofilm was 500 μM. Curcumin reduced the biofilm metabolism from 5 min to 24 h. Curcumin inhibited the quantity of live bacteria and total bacteria in both the short term (5 min) and the long term. Moreover, curcumin decreased the production of extracellular polysaccharide in the short term. The expression of genes related to extracellular polysaccharide synthesis, carbohydrate metabolism, adherence, and the two-component transduction system decreased after curcumin treatment. The chlorhexidine-treated group showed similar results. We speculate that curcumin has the capacity to be developed as an alternative agent with the potential to reduce the pathogenic traits of S. mutans biofilm.}, } @article {pmid29681899, year = {2018}, author = {Cieplik, F and Steinwachs, VS and Muehler, D and Hiller, KA and Thurnheer, T and Belibasakis, GN and Buchalla, W and Maisch, T}, title = {Phenalen-1-one-Mediated Antimicrobial Photodynamic Therapy: Antimicrobial Efficacy in a Periodontal Biofilm Model and Flow Cytometric Evaluation of Cytoplasmic Membrane Damage.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {688}, pmid = {29681899}, issn = {1664-302X}, abstract = {In light of increasing resistance toward conventional antibiotics and antiseptics, antimicrobial photodynamic therapy (aPDT) may be a valuable alternative, especially for use in dentistry. In this regard, photosensitizers (PS) based on a phenalen-1-one structure seem to be especially favorable due to their high singlet oxygen quantum yield. However, the actual target structures of phenalen-1-one-mediated aPDT are still unclear. The aim of the present study was to investigate the antimicrobial efficacy of aPDT mediated by phenalen-1-one derivatives SAPYR and SAGUA for inactivation of a polymicrobial biofilm consisting of three putative periodontal pathogens in vitro and to get first insights in the mechanism of action of phenalen-1-one-mediated aPDT by assessing damage of cytoplasmic membranes. aPDT with SAPYR exhibited identical antimicrobial efficacy as compared to chlorhexidine (CHX) [4.4-6.1 log10 reduction of colony forming units (CFUs) depending on bacterial species] while aPDT with SAGUA was less effective (2.0-2.8 log10). Flow cytometric analysis combined with propidium iodide (PI) staining revealed no damage of cytoplasmic membranes after aPDT with both phenalen-1-one derivatives, which was confirmed by spectroscopic measurements for release of nucleic acids after treatment. Spectrophotometric PS-uptake measurements showed no uptake of SAPYR by bacterial cells. Despite the inability to pinpoint the actual target of phenalen-1-one-mediated aPDT, this study shows the high antimicrobial potential of phenalen-1-on mediated aPDT (especially when using SAPYR) and represents a first step for getting insights in the mechanism and damage patterns of aPDT with this class of PS.}, } @article {pmid29680931, year = {2018}, author = {Rajkumari, J and Borkotoky, S and Murali, A and Suchiang, K and Mohanty, SK and Busi, S}, title = {Cinnamic acid attenuates quorum sensing associated virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1.}, journal = {Biotechnology letters}, volume = {40}, number = {7}, pages = {1087-1100}, doi = {10.1007/s10529-018-2557-9}, pmid = {29680931}, issn = {1573-6776}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans/drug effects/microbiology ; Cinnamates/*pharmacology ; Models, Molecular ; Protective Agents/pharmacology ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Virulence Factors/*metabolism ; }, abstract = {OBJECTIVE: Anti-quorum sensing and anti-biofilm efficacy of Cinnamic acid against Pseudomonas aeruginosa was comparatively assessed with respect to potent quorum sensing inhibitor, Baicalein.

RESULTS: At sub-lethal concentration, Cinnamic acid effectively inhibited both the production of the QS-dependent virulence factors and biofilm formation in P. aeruginosa without affecting the viability of the bacterium. The phytocompound interfered with the initial attachment of planktonic cells to the substratum thereby causing reduction in biofilm development. In addition, the in vivo study indicated that the test compound protected Caenorhabditis elegans from the virulence factors of P. aeruginosa leading to reduced mortality. The in silico analysis revealed that Cinnamic acid can act as a competitive inhibitor for the natural ligands towards the ligand binding domain of the transcriptional activators of the quorum sensing circuit in P. aeruginosa, LasR and RhlR.

CONCLUSIONS: The findings suggest that Cinnamic acid may serve as a novel quorum sensing based anti-infective in controlling P. aeruginosa infections.}, } @article {pmid29680469, year = {2018}, author = {Misba, L and Zaidi, S and Khan, AU}, title = {Efficacy of photodynamic therapy against Streptococcus mutans biofilm: Role of singlet oxygen.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {183}, number = {}, pages = {16-21}, doi = {10.1016/j.jphotobiol.2018.04.024}, pmid = {29680469}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/radiation effects ; Light ; Methylene Blue/*analogs & derivatives/chemistry/pharmacology ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Photosensitizing Agents/chemistry/*pharmacology ; RNA, Ribosomal, 16S/genetics/metabolism ; Singlet Oxygen/*metabolism ; Streptococcus mutans/drug effects/metabolism/*physiology ; Tolonium Chloride/*chemistry/pharmacology ; Transcriptome/drug effects/radiation effects ; }, abstract = {In photodynamic therapy (PDT), killing is entirely based on the ROS generation and among different types of ROS generated during PDT, singlet oxygen is considered as the most potential as illustrated in many studies and therefore it is predominantly responsible for photodamage and cytotoxic reactions. The aim of this study was to check whether singlet oxygen (Type II photochemistry) is more potential than free radicals (Type I photochemistry) against Streptococcus mutans biofilm. We have taken two phenothiazinium dyes i.e. toluidine blue O (TBO) and new methylene blue (NMB). TBO was found to have better antibacterial as well as antibiofilm effect than NMB. Antibacterial effect was evaluated by colony forming unit while antibiofilm action by crystal violet and congo red binding assays. We have also evaluated the disruption of preformed biofilm by biofilm reduction assay, confocal laser electron and scanning electron microscopy. More singlet oxygen production was detected in case of TBO than NMB while more Free radical (HO) was produced by NMB than TBO. TBO showed better antibacterial as well as antibiofilm effect than NMB so; we conclude that potency of a photosensitizer is correlated with the capability to produce singlet oxygen.}, } @article {pmid29679886, year = {2018}, author = {Vieira, TI and Câmara, JVF and Cardoso, JG and Alexandria, AK and Pintor, AVB and Villaça, JC and Cabral, LM and Romanos, MTV and Fonseca-Gonçalves, A and Valença, AMG and Maia, LC}, title = {Cytotoxicity of novel fluoride solutions and their influence on mineral loss from enamel exposed to a Streptococcus mutans biofilm.}, journal = {Archives of oral biology}, volume = {91}, number = {}, pages = {57-62}, doi = {10.1016/j.archoralbio.2018.04.008}, pmid = {29679886}, issn = {1879-1506}, mesh = {2-Hydroxypropyl-beta-cyclodextrin/pharmacology ; Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Cell Line/drug effects ; Cell Survival/drug effects ; Dental Caries/drug therapy/prevention & control ; Dental Enamel/*drug effects ; Fibroblasts/drug effects ; Fluorides/*pharmacology ; Hardness ; Humans ; Materials Testing ; Microbial Sensitivity Tests ; Minerals ; Nanotechnology ; Phosphates ; Streptococcus mutans/*drug effects ; Surface Properties ; Titanium/pharmacology ; Tooth Demineralization/*prevention & control ; gamma-Cyclodextrins/pharmacology ; }, abstract = {OBJECTIVE: This study evaluated the cytotoxicity, antimicrobial activity and in vitro influence of new fluoridated nanocomplexes on dental demineralization.

DESIGN: The nanocomplexes hydroxypropyl-β-cyclodextrin with 1% titanium tetrafluoride (TiF4) and γ-cyclodextrin with TiF4 were compared to a positive control (TiF4), a blank control (without treatment) and negative controls (hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, deionized water), following 12- and 72-hour complexation periods. The cytotoxicity was assessed using the neutral red dye uptake assay at T1-15 min, T2-30 min and T3-24 h. A minimum bactericidal concentration (MBC) against Streptococcus mutans (ATCC 25175) was performed. Enamel blocks were exposed to an S. mutans biofilm, and the percentage of surface microhardness loss was obtained. Biocompatibility and microhardness data were analysed using ANOVA/Tukey tests (p < 0.05).

RESULTS: At T1, the cell viability results of the nanocomplexes were similar to that of the blank control. At T2 and T3, the 72 h nanocomplexes demonstrated cell viability results similar to that of the blank, while the 12 h solutions showed results different from that of the blank (p < 0.05). All fluoridated nanocompounds inhibited S. mutans (MBC = 0.25%), while the MBC of TiF4 alone was 0.13%. All fluoridated compounds presented a percentage of surface microhardness loss lower than that of deionized water (p < 0.05).

CONCLUSIONS: The new fluoridated nanocomplexes did not induce critical cytotoxic effects during the experimental periods, whilst they did show bactericidal potential against S. mutans and inhibited enamel mineral loss.}, } @article {pmid29679779, year = {2018}, author = {Raic, A and Riedel, S and Kemmling, E and Bieback, K and Overhage, J and Lee-Thedieck, C}, title = {Biomimetic 3D in vitro model of biofilm triggered osteomyelitis for investigating hematopoiesis during bone marrow infections.}, journal = {Acta biomaterialia}, volume = {73}, number = {}, pages = {250-262}, doi = {10.1016/j.actbio.2018.04.024}, pmid = {29679779}, issn = {1878-7568}, mesh = {Biofilms/*growth & development ; Biomimetic Materials/*pharmacology ; *Bone Marrow Diseases/metabolism/microbiology/pathology ; Cells, Cultured ; *Hematopoiesis ; Humans ; Implants, Experimental/adverse effects/*microbiology ; Methicillin-Resistant Staphylococcus aureus/*physiology ; *Models, Biological ; *Osteomyelitis/metabolism/microbiology/pathology ; *Staphylococcal Infections/metabolism/microbiology/pathology ; }, abstract = {UNLABELLED: In this work, we define the requirements for a human cell-based osteomyelitis model which overcomes the limitations of state of the art animal models. Osteomyelitis is a severe and difficult to treat infection of the bone that develops rapidly, making it difficult to study in humans. We have developed a 3D in vitro model of the bone marrow, comprising a macroporous material, human hematopoietic stem and progenitor cells (HSPCs) and mesenchymal stromal cells (MSCs). Inclusion of biofilms grown on an implant into the model system allowed us to study the effects of postoperative osteomyelitis-inducing bacteria on the bone marrow. The bacteria influenced the myeloid differentiation of HSPCs as well as MSC cytokine expression and the MSC ability to support HSPC maintenance. In conclusion, we provide a new 3D in vitro model which meets all the requirements for investigating the impact of osteomyelitis.

STATEMENT OF SIGNIFICANCE: Implant-associated osteomyelitis is a persistent bacterial infection of the bone which occurs in many implant patients and can result in functional impairments or even entire loss of the extremity. Nevertheless, surprisingly little is known on the triangle interaction between implant material, bacterial biofilm and affected bone tissue. Closing this gap of knowledge would be crucial for the fundamental understanding of the disease and the development of novel treatment strategies. For this purpose, we developed the first biomaterial-based system that is able to mimic implant-associated osteomyelitis outside of the body, thus, opening the avenue to study this fatal disease in the laboratory.}, } @article {pmid29679633, year = {2018}, author = {Yue, J and Yang, H and Liu, S and Song, F and Guo, J and Huang, C}, title = {Influence of naringenin on the biofilm formation of Streptococcus mutans.}, journal = {Journal of dentistry}, volume = {76}, number = {}, pages = {24-31}, doi = {10.1016/j.jdent.2018.04.013}, pmid = {29679633}, issn = {1879-176X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Dental Pulp/cytology/drug effects ; *Flavanones/pharmacology/toxicity ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/genetics ; Humans ; Microbial Sensitivity Tests ; *Streptococcus mutans/drug effects ; }, abstract = {OBJECTIVES: To evaluate the effect of naringenin on the biofilm formation of Streptococcus mutans (S. mutans), and to investigate its mechanisms of action and biological toxicity.

METHODS: Minimum inhibitory concentrations, growth curves, and biofilm inhibition rates of naringenin were determined to assess its antimicrobial effect on S. mutans. The morphology of S. mutans and the structure of biofilm were observed by FESEM and CLSM. Bacterial aggregation, bacterial surface hydrophobicity, and real-time PCR for gtfB, gtfC, comD, comE, and luxS mRNA expression were assessed to preliminarily investigate the mechanisms of action. MTT test using human dental pulp cells (HDPCs) was also performed to investigate cytotoxicity.

RESULTS: The S.mutans growth curves, FESEM, CLSM showed that both 100 and 200 μg/mL of naringenin obviously inhibited S. mutans growth and biofilm formation, increased S. mutans surface hydrophobicity, reduced bacterial aggregation, and downregulated the mRNA expression of gtfB, gtfC, comD, comE, and luxS. However, naringenin at 200 μg/mL slightly decreased the growths of HDPCs compared with 100 μg/mL.

CONCLUSION: Naringenin at 100 and 200 μg/mL suppressed the second (bacterial adhesion) and third stages (biofilm maturation) of S. mutans biofilm formation.

CLINICAL SIGNIFICANCE: Naringenin is promising for dental clinic promotion to prevent the biofilm formation of S. mutans, serving as a safe anti-caries agent at an appropriate concentration.}, } @article {pmid29679527, year = {2018}, author = {Hayati, A and Najafi, F and Tabatabaei, FS}, title = {Effects of a new chlorhexidine varnish on Streptococcus mutans biofilm formation in vitro.}, journal = {Journal of basic and clinical physiology and pharmacology}, volume = {29}, number = {5}, pages = {573-579}, doi = {10.1515/jbcpp-2017-0050}, pmid = {29679527}, issn = {2191-0286}, mesh = {Biofilms/*drug effects/growth & development ; Chlorhexidine/chemistry/*pharmacology ; Disinfectants/*pharmacology ; *Paint ; Solubility ; Streptococcus mutans/*drug effects/physiology ; }, } @article {pmid29678464, year = {2018}, author = {Jain, T and Muktapuram, PR and Sharma, K and Ravi, O and Pant, G and Mitra, K and Bathula, SR and Banerjee, D}, title = {Biofilm inhibition and anti-Candida activity of a cationic lipo-benzamide molecule with twin-nonyl chain.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {28}, number = {10}, pages = {1776-1780}, doi = {10.1016/j.bmcl.2018.04.024}, pmid = {29678464}, issn = {1464-3405}, mesh = {Alkanes/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Benzamides/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects ; Candida albicans/cytology/*drug effects ; Cations/chemical synthesis/chemistry/pharmacology ; Cell Line ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {A series of cationic lipo-benzamide compounds with varying lengths of hydrocarbon chains (C2M-C18M) were evaluated for anti-Candida activity. Four compounds harbouring 8-11 hydrocarbon chains demonstrated concentration-dependent inhibition of fungal cell growth with Minimum Inhibitory Concentration (MIC) of ≤6.2 µg ml[-1]. The most active compound (C9M) inhibited growth of both Candida albicans and non-albicans strains and is equally active against pairs of azole sensitive and resistant clinical isolates of C. albicans. Compound C9M also inhibited different stages of Candida biofilms. Scanning Electron Microscopy (SEM) of Candida cells after C9M treatment was also done and no significant cell lysis was observed. Hemolysis assay was performed and only 2.5% haemolysis was observed at MIC concentration.}, } @article {pmid29678329, year = {2018}, author = {Pantaroto, HN and Ricomini-Filho, AP and Bertolini, MM and Dias da Silva, JH and Azevedo Neto, NF and Sukotjo, C and Rangel, EC and Barão, VAR}, title = {Antibacterial photocatalytic activity of different crystalline TiO2 phases in oral multispecies biofilm.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {34}, number = {7}, pages = {e182-e195}, doi = {10.1016/j.dental.2018.03.011}, pmid = {29678329}, issn = {1879-0097}, mesh = {Actinomyces ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Elastic Modulus ; Fusobacterium nucleatum ; Hardness ; Materials Testing ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Photochemical Processes ; Spectrometry, X-Ray Emission ; Streptococcus sanguis ; Surface Properties ; Titanium/chemistry/*pharmacology ; X-Ray Diffraction ; }, abstract = {OBJECTIVE: Titanium dioxide (TiO2) incorporation in biomaterials is a promising technology due to its photocatalytic and antibacterial activities. However, the antibacterial potential of different TiO2 crystalline structures on a multispecies oral biofilm remains unknown. We hypothesized that the different crystalline TiO2 phases present different photocatalytic and antibacterial activities.

METHODS: Three crystalline TiO2 films were deposited by magnetron sputtering on commercially pure titanium (cpTi), in order to obtain four groups: (1) machined cpTi (control); (2) A-TiO2 (anatase); (3) M-TiO2 (mixture of anatase and rutile); (4) R-TiO2 (rutile). The morphology, crystalline phase, chemical composition, hardness, elastic modulus and surface free energy of the surfaces were evaluated. The photocatalytic potential was assessed by methylene blue degradation assay. The antibacterial activity was evaluated on relevant oral bacteria, by using a multispecies biofilm (Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum) formed on the treated titanium surfaces (16.5h) followed by UV-A light exposure (1h) to generate reactive oxygen species production.

RESULTS: All TiO2 films presented around 300nm thickness and improved the hardness and elastic modulus of cpTi surfaces (p<0.05). A-TiO2 and M-TiO2 films presented superior photocatalytic activity than R-TiO2 (p<0.05). M-TiO2 revealed the greatest antibacterial activity followed by A-TiO2 (≈99.9% and 99% of bacterial reduction, respectively) (p<0.001 vs. control). R-TiO2 had no antibacterial activity (p>0.05 vs. control).

SIGNIFICANCE: This study brings new insights on the development of extra oral protocols for the photocatalytic activity of TiO2 in oral biofilm-associated disease. Anatase and mixture-TiO2 showed antibacterial activity on this oral bacterial biofilm, being promising surface coatings for dental implant components.}, } @article {pmid29678300, year = {2018}, author = {Yan, Q and Karau, MJ and Patel, R}, title = {In vitro activity of oritavancin against planktonic and biofilm states of vancomycin-susceptible and vancomycin-resistant enterococci.}, journal = {Diagnostic microbiology and infectious disease}, volume = {91}, number = {4}, pages = {348-350}, doi = {10.1016/j.diagmicrobio.2018.03.008}, pmid = {29678300}, issn = {1879-0070}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Multiple, Bacterial ; Enterococcus/*drug effects/physiology ; Lipoglycopeptides/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Vancomycin-Resistant Enterococci/*drug effects/physiology ; }, abstract = {We tested the in vitro activity of oritavancin against 60 vancomycin-susceptible enterococci (VSE) and 27 vancomycin-resistant enterococci (VRE). The oritavancin MIC ranged from ≤0.002 to 0.5μg/mL; the minimum biofilm bactericidal concentration ranged from ≤0.002 to 2μg/mL. Oritavancin has promising in vitro activity against VSE and VRE in both planktonic and biofilm states.}, } @article {pmid29676958, year = {2018}, author = {Vinod Kumar, K and Lall, C and Vimal Raj, R and Vedhagiri, K and Sunish, IP and Vijayachari, P}, title = {Can Subminimal Inhibitory Concentrations of Antibiotics Induce the Formation of Biofilm in Leptospira?.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {24}, number = {7}, pages = {1040-1042}, doi = {10.1089/mdr.2017.0409}, pmid = {29676958}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Doxycycline/pharmacology ; Humans ; Leptospira/*drug effects ; Microbial Sensitivity Tests/methods ; Tetracycline/pharmacology ; }, abstract = {Antibiotics at subminimal inhibitory concentrations (sub-MICs) are known to induce biofilm formation in numerous bacteria in vitro. In this report, the effect of sub-MIC levels of antibiotics (doxycycline and tetracycline) on biofilm formation by leptospiral reference strains and isolates was investigated. The sub-MIC levels of both tetracycline and doxycycline were able to induce biofilm in some of the leptospiral strains. This is the first report demonstrating the effect of sub-MIC level of antibiotics in inducing biofilm formation in Leptospira. The induction of biofilm may solely be a response to the amount of threshold stress enforced by low levels of antibiotics. The mechanism of biofilm induction by subinhibitory antibiotic concentrations needs to be explored further. Studies are required to understand the clinical relevance of the phenomenon and its contribution to biofilm formation in the host, resulting in the failure of antimicrobial therapy during the treatment of chronic leptospirosis.}, } @article {pmid29676891, year = {2018}, author = {Gennari, O and Marchesano, V and Rega, R and Mecozzi, L and Nazzaro, F and Fratianni, F and Coppola, R and Masucci, L and Mazzon, E and Bramanti, A and Ferraro, P and Grilli, S}, title = {Pyroelectric Effect Enables Simple and Rapid Evaluation of Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {18}, pages = {15467-15476}, doi = {10.1021/acsami.8b02815}, pmid = {29676891}, issn = {1944-8252}, mesh = {Bacteria ; *Biofilms ; Reproducibility of Results ; }, abstract = {Biofilms are detrimental to human life and industrial processes due to potential infections, contaminations, and deterioration. Therefore, the evaluation of microbial capability to form biofilms is of fundamental importance for assessing how different environmental factors may affect their vitality. Nowadays, the approaches used for biofilm evaluation are still poor in reliability and rapidity and often provide contradictory results. Here, we present what we call biofilm electrostatic test (BET) as a simple, rapid, and highly reproducible tool for evaluating in vitro the ability of bacteria to form biofilms through electrostatic interaction with a pyroelectrified carrier. The results show how the BET is able to produce viable biofilms with a density 6-fold higher than that on the control, after just 2 h incubation. The BET could pave the way to a rapid standardization of the evaluation of bacterial resistance among biofilm-producing microorganisms. In fact, due to its simplicity and cost-effectiveness, it is well suited for a rapid and easy implementation in a microbiology laboratory.}, } @article {pmid29676752, year = {2018}, author = {Azari, M and Le, AV and Lübken, M and Denecke, M}, title = {Model-based analysis of microbial consortia and microbial products in an anammox biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {7-8}, pages = {1951-1959}, doi = {10.2166/wst.2018.081}, pmid = {29676752}, issn = {0273-1223}, mesh = {Ammonium Compounds/*metabolism ; Anaerobiosis ; *Bacterial Physiological Phenomena ; *Biofilms ; *Bioreactors ; Microbial Consortia/*physiology ; Models, Biological ; Nitrogen/*metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {A mathematical model for a granular biofilm reactor for leachate treatment was validated by long-term measured data to investigate the mechanisms and drivers influencing biological nitrogen removal and microbial consortia dynamics. The proposed model, based on Activated Sludge Model (ASM1), included anaerobic ammonium oxidation (anammox), nitrifying and heterotrophic denitrifying bacteria which can attach and grow on granular activated carbon (GAC) particles. Two kinetic descriptions for the model were proposed: with and without soluble microbial products (SMP) and extracellular polymeric substance (EPS). The model accuracy was checked using recorded total inorganic nitrogen concentrations in the effluent and estimated relative abundance of active bacteria using quantitative fluorescence in-situ hybridization (qFISH). Results suggested that the model with EPS kinetics fits better for the relative abundance of anammox bacteria and nitrifying bacteria compared to the model without EPS. The model with EPS and SMP confirms that the growth and existence of heterotrophs in anammox biofilm systems slightly increased due to including the kinetics of SMP production in the model. During the one-year simulation period, the fractions of autotrophs and EPS in the biomass were almost stable but the fraction of heterotrophs decreased which is correlated with the reduction in nitrogen surface loading on the biofilm.}, } @article {pmid29675012, year = {2018}, author = {Zhou, YH and Xu, CG and Yang, YB and Xing, XX and Liu, X and Qu, QW and Ding, WY and Bello-Onaghise, G and Li, YH}, title = {Histidine Metabolism and IGPD Play a Key Role in Cefquinome Inhibiting Biofilm Formation of Staphylococcus xylosus.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {665}, pmid = {29675012}, issn = {1664-302X}, abstract = {Staphylococcus xylosus (S. xylosus) is an AT-rich and coagulase-negative Staphylococcus (CNS). It is normally regarded as non-pathogenic, however, recent studies have demonstrated that it is related to human opportunistic infections and bovine mastitis. In addition, S. xylosus strains have the ability to form biofilm. Biofilms are also involved in chronic infections and antibiotic resistance, there are only a few reports about cefquinome inhibiting S. xylosus biofilm formation and the protein targets of cefquinome. In our study, we found that sub-MICs of cefquinome were sufficient to inhibit biofilm formation. To investigate the potential protein targets of cefquinome, we used iTRAQ for the analyses of cells at two different conditions: 1/2-MIC (0.125 μg/mL) cefquinome treatment and no treatment. Using iTRAQ technique and KEGG database analysis, we found that proteins differently expression in histidine metabolism pathway may play a role in the process by which 1/2-MIC (0.125 μg/mL) cefquinome inhibits S. xylosus biofilm formation. Interestingly, we found a sharply down-regulated enzyme [A0A068E9J3 imidazoleglycerol-phosphate dehydratase (IGPD)] involved in histidine metabolism pathway in cefquinome-treated cells. We demonstrated the important role of IGPD in sub-MICs cefquinome inhibiting biofilm formation of S. xylosus by gene (hisB) knockout, IGPD enzyme activity and histidine content assays. Thus, our data sheds light on important role of histidine metabolism in S. xylosus biofilm formation; especially, IGPD involved in histidine metabolism might play a crucial role in sub-MICs cefquinome inhibition of biofilm formation of S. xylosus, and we propose IGPD as an attractive protein target of cefquinome.}, } @article {pmid29674848, year = {2018}, author = {Chernysh, S and Gordya, N and Tulin, D and Yakovlev, A}, title = {Biofilm infections between Scylla and Charybdis: interplay of host antimicrobial peptides and antibiotics.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {501-514}, pmid = {29674848}, issn = {1178-6973}, abstract = {PURPOSE: The aim of this study is to improve the anti-biofilm activity of antibiotics. We hypothesized that the antimicrobial peptide (AMP) complex of the host's immune system can be used for this purpose and examined the assumption on model biofilms.

METHODS: FLIP7, the AMP complex of the blowfly Calliphora vicina containing a combination of defensins, cecropins, diptericins and proline-rich peptides was isolated from the hemolymph of bacteria-challenged maggots. The complex interaction with antibiotics of various classes was studied in biofilm and planktonic cultures of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii by the checkerboard method using trimethyl tetrazolium chloride cell viability and crystal violet biofilm eradication assays supplemented with microscopic analysis.

RESULTS: We found that FLIP7 demonstrated: high synergy (fractional inhibitory concentration index <0.25) with meropenem, amikacin, kanamycin, ampicillin, vancomycin and cefotaxime; synergy with clindamycin, erythromycin and chloramphenicol; additive interaction with oxacillin, tetracycline, ciprofloxacin and gentamicin; and no interaction with polymyxin B. The interaction in planktonic cell models was significantly weaker than in biofilms of the same strains. The analysis of the dose-effect curves pointed to persister cells as a likely target of FLIP7 synergistic effect. The biofilm eradication assay showed that the effect also caused total destruction of S. aureus and E. coli biofilm materials. The effect allowed reducing the effective anti-biofilm concentration of the antibiotic to a level well below the one clinically achievable (2-3 orders of magnitude in the case of meropenem, ampicillin, cefotaxime and oxacillin).

CONCLUSION: FLIP7 is a highly efficient host antimicrobial system helping antibiotics to overcome biofilm barriers through persisters' sensitization and biofilm material destruction. It is promising for the treatment of biofilm infections as an adjuvant of various small-molecule antibiotics.}, } @article {pmid29674703, year = {2018}, author = {Dang, MH and Jung, JE and Choi, HM and Jeon, JG}, title = {Difference in virulence and composition of a cariogenic biofilm according to substratum direction.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {6244}, pmid = {29674703}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Dental Caries/*microbiology ; Durapatite/chemistry ; Microscopy, Electron, Scanning ; Streptococcus mutans ; Surface Properties ; *Virulence ; }, abstract = {The aim of this study was to investigate the difference in composition and virulence of Streptococcus mutans biofilms according to substratum direction. S. mutans biofilms (46-h-old) were formed on three different saliva-coated hydroxyapatite (sHA) disc direction groups: downward (discs placed in the direction of gravity), vertical (discs placed parallel to gravity direction), and upward (discs placed opposite to gravity). The 46-h-old biofilms on sHA discs in the upward direction showed the highest biofilm accumulation, colony forming unit (CFU) count, and extracellular polysaccharide (EPS) amount, followed by those in the vertical and downward directions. In the confocal laser scanning microscopy (CLSM) study, the biofilms in the upward direction also showed the highest bacterial count (live or dead cells) and EPS biovolume. Scanning electron microscopy (SEM) analysis confirmed the microbiological and biochemical results. In addition, biofilm density and acid production were higher in the upward direction than those in the other directions. Our findings suggest that substratum direction, which might be related to gravity, strongly influences the formation and virulence of cariogenic biofilms and subsequent initiation of dental caries. Collectively, the differences in the formation and virulence of cariogenic biofilms are related to the direction of tooth surface (occlusal surfaces of mandibular teeth > proximal surfaces > occlusal surfaces of maxillary teeth).}, } @article {pmid29673789, year = {2018}, author = {Wahlen, LK and Mantei, JR and DiOrio, JP and Jones, CM and Pasmore, ME}, title = {Production and analysis of a Bacillus subtilis biofilm comprised of vegetative cells and spores using a modified colony biofilm model.}, journal = {Journal of microbiological methods}, volume = {148}, number = {}, pages = {181-187}, doi = {10.1016/j.mimet.2018.04.011}, pmid = {29673789}, issn = {1872-8359}, mesh = {Bacillus subtilis/*growth & development/metabolism ; Bacterial Proteins/analysis ; Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Microscopy ; Spectrum Analysis ; Spores, Bacterial/*growth & development/metabolism ; }, abstract = {Bacillus subtilis is a spore-forming soil bacterium that is capable of producing robust biofilms. Sporulation can occur in B. subtilis biofilms and it is possible that the spores embedded in the protective matrix could present a significant challenge to disinfecting agents or processes. This article describes a method for the growth and quantification of a reproducible B. subtilis ATCC 35021 biofilm comprised of vegetative cells and spores using a modified colony biofilm model. In this method, membranes were inoculated and incubated for a total of 8 days to promote biofilm formation and subsequent sporulation within the biofilm. Representative samples were taken over the course of the incubation period to evaluate the biofilms using enumerative, microscopic, and spectrometric methods. At various time points, the total numbers of cells and spores were quantified. A Congo red agar (CRA) method was utilized to detect the TasA matrix protein, a primary component of the B. subtilis biofilm matrix. The presence of TasA was also confirmed using mass spectrometry. The biofilm morphologies were correlated to the enumeration data with a variety of correlative imaging techniques: confocal microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). At the end of the incubation period, the biofilm contained >7 logs total colony forming units with spores comprising approximately 10% of the biofilm. The biofilm generated using this method allows researchers to use a new, more robust challenge for efficacy testing of chemical and physical antimicrobial treatments such as antibiotics, disinfectants, or heat.}, } @article {pmid29671721, year = {2018}, author = {Tian, XL and Salim, H and Dong, G and Parcells, M and Li, YH}, title = {The BceABRS four-component system that is essential for cell envelope stress response is involved in sensing and response to host defence peptides and is required for the biofilm formation and fitness of Streptococcus mutans.}, journal = {Journal of medical microbiology}, volume = {67}, number = {6}, pages = {874-883}, doi = {10.1099/jmm.0.000733}, pmid = {29671721}, issn = {1473-5644}, abstract = {Purpose. Streptococcus mutans is a primary cariogenic pathogen worldwide. In dental biofilms, S. mutans often faces life-threatening insults, such as killing by antimicrobial compounds from competing species and from the host. How such insults affect the physiology and virulence of S. mutans is poorly understood. In this study, we explored this question by investigating the responses of S. mutans strains to several host defence peptides and bacitracin.Methodology. S. mutans UA159 and its isogenic mutants, SmΔbceA, SmΔbceB, SmΔbceR and SmΔbceS, were examined for their antibiotic susceptibility and biofilm formation. The lux reporter strains were constructed to assay the responses of S. mutans to host defence peptides. In addition, the competitive fitness of these mutants against the parent in response to peptide antibiotics was determined in dual-strain mixed cultures.Results. S. mutans UA159 (WT) was generally insensitive to physiological concentrations of α-defensin-1, β-defensin-3, LL-37 and histatin-5, but all of the BceABRS mutants were sensitive to these peptide antibiotics. The response of S. mutans to these peptide antibiotics involved the transcriptional activation of the bceABRS operon itself. Bacitracin or β-defensin-3 at a sub-inhibitory concentration induced biofilm formation in the parent, but not in any of the BceABRS mutants. None of the mutants were able to compete with the parent for persistence in duel-strain cultures in the presence of bacitracin or β-defensin-3.Conclusion. The BceABRS four-component system in S. mutans is involved in sensing, response and resistance to host defence peptides, and is required for the biofilm formation and fitness of S. mutans.}, } @article {pmid29670843, year = {2018}, author = {Ribeiro, KVG and Ribeiro, C and Dias, RS and Cardoso, SA and de Paula, SO and Zanuncio, JC and de Oliveira, LL}, title = {Bacteriophage Isolated from Sewage Eliminates and Prevents the Establishment of Escherichia Coli Biofilm.}, journal = {Advanced pharmaceutical bulletin}, volume = {8}, number = {1}, pages = {85-95}, pmid = {29670843}, issn = {2228-5881}, abstract = {Purpose: Biofilm growth exerts a negative impact on industry and health, necessitating the development of strategies to control. The objective of this work was study the lytic activity of the phage isolated from the sewage network in the formation and degradation of Escherichia coli biofilms. Methods: E. coli cultures were incubated in 96-well polystyrene microplates under controlled conditions to evaluate the biofilm formation. The E. coli cultures and established biofilms were treated with the suspensions of the vB_EcoM-UFV017 (EcoM017) bacteriophage obtained from sewage for 24 hours. The E. coli bacterial density was measured using absorbance at 600 nm and the biofilms were measured by crystal violet staining. Polystyrene coupons were used as support for Scanning Electron Microscopy and Confocal Microscopy to evaluate biofilm formation. Results: The E. coli strains formed biofilms in polystyrene microplates after 48 hours' incubation. The highest EcoM017 phage titer, in the prevention and degradation experiments, reduced the bacterial growth and the quantity of biofilm formed by E. coli in 90.0% and 87.5%, respectively. The minimum dose capable of reducing the biofilms of this bacterium was 10[1] PFU/mL after 24 hours. The preformed E. coli biofilm mass was reduced 79% post exposure to the phage in the degradation assay. Microscopic analysis confirmed the results obtained in the plates assays. Conclusion: The EcoM017 phage prevented biofilm formation and degraded the E. coli-established ones. The EcoM017 phage isolated from sewage can reduce bacterial attachment and lyse the E. coli associated biofilm cells, offering biotechnological potential applicability for this phage.}, } @article {pmid29670217, year = {2018}, author = {Kim, D and Liu, Y and Benhamou, RI and Sanchez, H and Simón-Soro, Á and Li, Y and Hwang, G and Fridman, M and Andes, DR and Koo, H}, title = {Bacterial-derived exopolysaccharides enhance antifungal drug tolerance in a cross-kingdom oral biofilm.}, journal = {The ISME journal}, volume = {12}, number = {6}, pages = {1427-1442}, pmid = {29670217}, issn = {1751-7370}, support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE025848/DE/NIDCR NIH HHS/United States ; R03 DE025728/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Antifungal Agents/pharmacology ; Bacterial Infections/*microbiology ; Biofilms/*drug effects ; Candida albicans/*physiology ; Drug Tolerance ; Enzymes/chemistry ; Female ; Fluconazole/pharmacology ; Glucans/chemistry ; Metagenome ; Mouth Diseases/microbiology ; Mycoses/*microbiology ; Polysaccharides, Bacterial/*chemistry ; Povidone-Iodine/pharmacology ; Rats ; Rats, Sprague-Dawley ; Streptococcus mutans/*physiology ; }, abstract = {Fungal-bacterial interactions generate unique biofilms that cause many infections in humans. Candida albicans interact with Streptococcus mutans in dental biofilms associated with severe childhood tooth-decay, a prevalent pediatric oral disease. Current modalities are ineffective and primarily based on antimicrobial monotherapies despite the polymicrobial nature of the infection. Here, we show that the combination of clinically used topical antifungal fluconazole with povidone iodine (PI) can completely suppress C. albicans carriage and mixed-biofilm formation without increasing bacterial killing activity in vivo. We unexpectedly found that the inclusion of PI enhanced fluconazole efficacy by potently disrupting the assembly of a protective bacterial exopolysaccharide (EPS) matrix through inhibition of α-glucan synthesis by S. mutans exoenzyme (GtfB) bound on the fungal surface. Further analyses revealed that the EPS produced in situ directly bind and sequester fluconazole, reducing uptake and intracellular transportation of the drug. Conversely, inhibition of GtfB activity by PI, enzymatic degradation of the α-glucan matrix or co-culturing with gtfB-defective S. mutans re-established antifungal susceptibility. Hence, topical antifungal has limitations in mixed oral biofilms due to enhanced C. albicans tolerance to fluconazole afforded by the shielding effect of bacterial-derived EPS. The data provide new insights for treatment of C. albicans in cross-kingdom biofilms, indicating that EPS inhibitors may be required for enhanced killing efficacy and optimal anti-biofilm activity.}, } @article {pmid29670216, year = {2018}, author = {Liu, W and Russel, J and Burmølle, M and Sørensen, SJ and Madsen, JS}, title = {Micro-scale intermixing: a requisite for stable and synergistic co-establishment in a four-species biofilm.}, journal = {The ISME journal}, volume = {12}, number = {8}, pages = {1940-1951}, pmid = {29670216}, issn = {1751-7370}, mesh = {Actinobacteria/physiology ; *Bacterial Physiological Phenomena ; *Biofilms ; Biomass ; *Microbial Interactions ; Paenibacillus/physiology ; Stenotrophomonas/physiology ; Xanthomonas/physiology ; }, abstract = {Microorganisms frequently coexist in complex multispecies communities, where they distribute non-randomly, reflective of the social interactions that occur. It is therefore important to understand how social interactions and local spatial organization influences multispecies biofilm succession. Here the localization of species pairs was analyzed in three dimensions in a reproducible four-species biofilm model, to study the impact of spatial positioning of individual species on the temporal development of the community. We found, that as the biofilms developed, species pairs exhibited distinct intermixing patterns unique to the four-member biofilms. Higher biomass and more intermixing were found in four-species biofilms compared to biofilms with fewer species. Intriguingly, in local regions within the four member biofilms where Microbacterium oxydans was scant, both biomass and intermixing of all species were lowered, compared to regions where M. oxydans was present at typical densities. Our data suggest that Xanthomonas retroflexus and M. oxydans, both low abundant biofilm-members, intermixed continuously during the development of the four-species biofilm, hereby facilitating their own establishment. In turn, this seems to have promoted distinct spatial organization of Stenotrophomonas rhizophila and Paenibacillus amylolyticus enabling enhanced growth of all four species. Here local intermixing of bacteria advanced the temporal development of a multi-species biofilm.}, } @article {pmid29669887, year = {2018}, author = {Van Laar, TA and Esani, S and Birges, TJ and Hazen, B and Thomas, JM and Rawat, M}, title = {Pseudomonas aeruginosa gshA Mutant Is Defective in Biofilm Formation, Swarming, and Pyocyanin Production.}, journal = {mSphere}, volume = {3}, number = {2}, pages = {}, pmid = {29669887}, issn = {2379-5042}, support = {SC3 GM100855/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial ; Fosfomycin/pharmacology ; Glutathione/metabolism ; Mutation ; Paraquat/pharmacology ; Pseudomonas aeruginosa/drug effects/*genetics/growth & development/*pathogenicity ; Pyocyanine/*biosynthesis ; Rifampin/pharmacology ; Virulence ; Virulence Factors/biosynthesis ; }, abstract = {Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can cause severe opportunistic infections. The principal redox buffer employed by this organism is glutathione (GSH). To assess the role of GSH in the virulence of P. aeruginosa, a number of analyses were performed using a mutant strain deficient in gshA, which does not produce GSH. The mutant strain exhibited a growth delay in minimal medium compared to the wild-type strain. Furthermore, the gshA mutant was defective in biofilm and persister cell formation and in swimming and swarming motility and produced reduced levels of pyocyanin, a key virulence factor. Finally, the gshA mutant strain demonstrated increased sensitivity to methyl viologen (a redox cycling agent) as well as the thiol-reactive antibiotics fosfomycin and rifampin. Taken together, these data suggest a key role for GSH in the virulence of P. aeruginosaIMPORTANCEPseudomonas aeruginosa is a ubiquitous bacterium that can cause severe opportunistic infections, including many hospital-acquired infections. It is also a major cause of infections in patients with cystic fibrosis. P. aeruginosa is intrinsically resistant to a number of drugs and is capable of forming biofilms that are difficult to eradicate with antibiotics. The number of drug-resistant strains is also increasing, making treatment of P. aeruginosa infections very difficult. Thus, there is an urgent need to understand how P. aeruginosa causes disease in order to find novel ways to treat infections. We show that the principal redox buffer, glutathione (GSH), is involved in intrinsic resistance to the fosfomycin and rifampin antibiotics. We further demonstrate that GSH plays a role in P. aeruginosa disease and infection, since a mutant lacking GSH has less biofilm formation, is less able to swarm, and produces less pyocyanin, a pigment associated with infection.}, } @article {pmid29668945, year = {2018}, author = {Karkowska-Kuleta, J and Bartnicka, D and Zawrotniak, M and Zielinska, G and Kieronska, A and Bochenska, O and Ciaston, I and Koziel, J and Potempa, J and Baster, Z and Rajfur, Z and Rapala-Kozik, M}, title = {The activity of bacterial peptidylarginine deiminase is important during formation of dual-species biofilm by periodontal pathogen Porphyromonas gingivalis and opportunistic fungus Candida albicans.}, journal = {Pathogens and disease}, volume = {76}, number = {4}, pages = {}, pmid = {29668945}, issn = {2049-632X}, support = {DE 022597/NH/NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Candida albicans/*pathogenicity/physiology ; Gene Expression ; Humans ; Microbial Interactions ; Porphyromonas gingivalis/enzymology/genetics/growth & development/*pathogenicity ; Protein-Arginine Deiminases/genetics/*metabolism ; Virulence Factors/genetics/*metabolism ; }, abstract = {Porphyromonas gingivalis, an anaerobic Gram-negative bacterium critically involved in the development of human periodontitis, belongs to the late colonizers of the oral cavity. The success of this pathogen in the host colonization and infection results from the presence of several virulence factors, including extracellular peptidylarginine deiminase (PPAD), an enzyme that converts protein arginine residues to citrullines. A common opportunistic fungal pathogen of humans, Candida albicans, is also frequently identified among microorganisms that reside at subgingival sites. The aim of the current work was to verify if protein citrullination can influence the formation of mixed biofilms by both microorganisms under hypoxic and normoxic conditions. Quantitative estimations of the bacterial adhesion to fungal cells demonstrated the importance of PPAD activity in this process, since the level of binding of P. gingivalis mutant strain deprived of PPAD was significantly lower than that observed for the wild-type strain. These results were consistent with mass spectrometric detection of the citrullination of selected surface-exposed C. albicans proteins. Furthermore, a viability of P. gingivalis cells under normoxia increased in the presence of fungal biofilm compared with the bacteria that formed single-species biofilm. These findings suggest a possible protection of these strict anaerobes under unfavorable aerobic conditions by C. albicans during mixed biofilm formation.}, } @article {pmid29668034, year = {2018}, author = {Cai, L and Wang, H and Liang, L and Wang, G and Xu, X and Wang, H}, title = {Response of Formed-Biofilm of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter freundii to Chlorite-Based Disinfectants.}, journal = {Journal of food science}, volume = {83}, number = {5}, pages = {1326-1332}, doi = {10.1111/1750-3841.14149}, pmid = {29668034}, issn = {1750-3841}, mesh = {Bacterial Infections/prevention & control ; Biofilms/*drug effects ; Chlorides/*pharmacology ; Chlorine/*pharmacology ; Chlorine Compounds/pharmacology ; Citrobacter freundii/*drug effects ; Disinfectants/*pharmacology ; Disinfection/methods ; Electrolysis ; Enterobacter cloacae/*drug effects ; Equipment and Supplies/microbiology ; Humans ; Hydrogen Peroxide/pharmacology ; Klebsiella oxytoca/*drug effects ; Oxides/pharmacology ; Sodium Hypochlorite/pharmacology ; }, abstract = {UNLABELLED: Bacterial biofilms formed on equipment surfaces are potential sources of cross-contamination and can be responsible for the spread of bacteria involved in food spoilage, such as some Enterobacteriaceae family members. In this study, the effect of chlorite-based disinfectants, including sodium hypochlorite (SH), chlorine dioxide (CD), strongly acidic electrolyzed water (StAEW), and neutral electrolyzed water (NEW), on inactivation of mono-biofilms of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter freundii was evaluated separately. All the strains were enumerated by the viable plate-count method after disinfection for 30 min. A comparison of the surviving cells after disinfection indicated that E. cloacae biofilms were more resistant to disinfectants than the biofilms of the other two strains, and treatment with all the disinfectants improved sanitizing. SH (200 mg/L) was the most effective in the reduction of cell number in the biofilms of all strains. Considering the safety of use and environmental protection, electrolyzed oxidizing water, especially StAEW, was a good suggestion for the inactivation of cells in K. oxytoca or C. freundii biofilms. These results suggest that the cells in biofilm of E. cloacae, K. oxytoca, and C. freundii were highly sensitive to chlorite-based disinfectants and provide insights into the efficacy of disinfectants in killing bacteria.

PRACTICAL APPLICATION: The Enterobacteriaceae biofilms formed on equipment surfaces, which can cause cross-contamination and food spoilage, are greatly challenging bacterial contaminants of food products. Electrolyzed oxidizing water is a novel, environmentally friendly disinfectant that can effectively treat Enterobacteriaceae biofilms. The results of this study may be used to design effective measures to disinfect biofilms on equipment contact surfaces.}, } @article {pmid29667430, year = {2018}, author = {Hussain, MS and Kwon, M and Tango, CN and Oh, DH}, title = {Effect of Electrolyzed Water on the Disinfection of Bacillus cereus Biofilms: The Mechanism of Enhanced Resistance of Sessile Cells in the Biofilm Matrix.}, journal = {Journal of food protection}, volume = {81}, number = {5}, pages = {860-869}, doi = {10.4315/0362-028X.JFP-17-450}, pmid = {29667430}, issn = {1944-9097}, mesh = {Bacillus cereus/drug effects/*physiology ; *Biofilms/drug effects ; Chlorine/pharmacology ; Disinfection ; Electrolysis ; Extracellular Polymeric Substance Matrix/chemistry ; Stainless Steel ; }, abstract = {This study examined the disinfection efficacy and mechanism of electrolyzed water (EW) on Bacillus cereus biofilms. B. cereus strains, ATCC 14579 and Korean Collection for Type Cultures (KCTC) 13153 biofilms, were formed on stainless steel (SS) and plastic slide (PS) coupons. Mature biofilms were treated with slightly acidic EW (SAEW), acidic EW (AEW), and basic EW (BEW). SAEW (available chlorine concentration, 25 ± 1.31 mg L[-1]; pH 5.71 ± 0.16; and oxidation reduction potential, 818 to 855 mV) reduced ATCC 14579 biofilms on plastic slides to below the detection limit within 30 s. However, biofilms on SS coupons showed a higher resistance to the SAEW treatment. When the disinfection activities of three types of EW on biofilms were compared, AEW showed a higher bactericidal activity, followed by SAEW and BEW. In contrast, BEW showed a significantly (P < 0.05) higher biofilm dispersal activity than AEW and SAEW. SAEW disinfection of the B. cereus biofilms was due to the disruption of the B. cereus plasma membrane. The higher resistance of biofilms formed on the SS coupon might be due to the higher number of attached cells and extracellular polymeric substances formation that reacts with the active chlorine ions, such as hypochlorous acid and hypochlorite ion of SAEW, which decreased the disinfection efficacy of SAEW. This study showed that the EW treatment effectively disinfected B. cereus biofilms, providing insight into the potential use of EW in the food processing industry to control the biofilm formation of B. cereus.}, } @article {pmid29667274, year = {2018}, author = {Černáková, L and Jordao, L and Bujdáková, H}, title = {Impact of farnesol and Corsodyl[®] on Candida albicans forming dual biofilm with Streptococcus mutans.}, journal = {Oral diseases}, volume = {24}, number = {6}, pages = {1126-1131}, doi = {10.1111/odi.12873}, pmid = {29667274}, issn = {1601-0825}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Chlorhexidine/*analogs & derivatives/pharmacology ; Farnesol/*pharmacology ; Mouthwashes/pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {OBJECTIVE: This work studied the biofilm formed by Candida albicans and Streptococcus mutans on a hydroxyapatite surface after exposure to the quorum-sensing molecule farnesol (200 μM) in comparison with the diluted mouthwash Corsodyl[®] (0.0001% chlorhexidine digluconate).

MATERIALS AND METHODS: The cytotoxicity of farnesol was evaluated by Galleria mellonella surviving assay. The viability of biofilm cells after exposure to farnesol and Corsodyl[®] was determined by colony-forming units. The morphology and structure of a dual-species biofilm was evaluated by scanning electron microscopy.

RESULTS: Farnesol did not exhibit a toxic effect on larval survival. While 200 μM farnesol effectively reduced the yeast-to-hyphae transition in the dual biofilm, it did not affect the growth of S. mutans. Additionally, despite the presence of farnesol, many blastospores were observed. Corsodyl[®] reduced S. mutans in the dual biofilm, but did not influence C. albicans.

CONCLUSION: This study showed that 200 μM farnesol modulated C. albicans in a dual-species biofilm with S. mutans, but did not exhibit antimicrobial activity against S. mutans. Moreover, it seems that S. mutans provides conditions that support the growth of the yeast form of C. albicans. The mouthwash Corsodyl[®] reduces S. mutans, but was not effective against C. albicans.}, } @article {pmid29663827, year = {2018}, author = {Hüwe, C and Schmeichel, J and Brodkorb, F and Dohlen, S and Kalbfleisch, K and Kreyenschmidt, M and Lorenz, R and Kreyenschmidt, J}, title = {Potential of antimicrobial treatment of linear low-density polyethylene with poly((tert-butyl-amino)-methyl-styrene) to reduce biofilm formation in the food industry.}, journal = {Biofouling}, volume = {34}, number = {4}, pages = {378-387}, doi = {10.1080/08927014.2018.1453926}, pmid = {29663827}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects ; Bacterial Physiological Phenomena ; *Biofilms ; Escherichia coli/drug effects/physiology ; Food Industry/*methods ; *Food Microbiology ; Listeria monocytogenes/drug effects/physiology ; Polyethylene/*pharmacology ; Pseudomonas fluorescens/drug effects/physiology ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Antimicrobial surfaces are one approach to prevent biofilms in the food industry. The aim of this study was to investigate the effect of poly((tert-butyl-amino)-methyl-styrene) (poly(TBAMS)) incorporated into linear low-density polyethylene (LLDPE) on the formation of mono- and mixed-species biofilms. The biofilm on untreated and treated LLDPE was determined after 48 and 168 h. The comparison of the results indicated that the ability of Listeria monocytogenes to form biofilms was completely suppressed by poly(TBAMS) (Δ168 h 3.2 log10 cfu cm[-2]) and colonization of Staphylococcus aureus and Escherichia coli was significantly delayed, but no effect on Pseudomonas fluorescens was observed. The results of dual-species biofilms showed complex interactions between the microorganisms, but comparable effects on the individual bacteria by poly(TBAMS) were identified. Antimicrobial treatment with poly(TBAMS) shows great potential to prevent biofilms on polymeric surfaces. However, a further development of the material is necessary to reduce the colonization of strong biofilm formers.}, } @article {pmid29663554, year = {2018}, author = {Mooney, JA and Pridgen, EM and Manasherob, R and Suh, G and Blackwell, HE and Barron, AE and Bollyky, PL and Goodman, SB and Amanatullah, DF}, title = {Periprosthetic bacterial biofilm and quorum sensing.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {36}, number = {9}, pages = {2331-2339}, doi = {10.1002/jor.24019}, pmid = {29663554}, issn = {1554-527X}, support = {R01 AI072666/AI/NIAID NIH HHS/United States ; 30416//Stanford University School of Medicine Medical Scholars Research Program/International ; }, mesh = {Adhesins, Bacterial/metabolism ; Anti-Bacterial Agents/*pharmacology ; Arthritis, Infectious ; Bacteria ; *Biofilms ; Cell Membrane/metabolism ; Humans ; Immune System ; Macromolecular Substances ; Prostheses and Implants ; Prosthesis-Related Infections/*microbiology ; *Quorum Sensing ; Virulence ; }, abstract = {Periprosthetic joint infection (PJI) is a common complication after total joint arthroplasty leading to severe morbidity and mortality. With an aging population and increasing prevalence of total joint replacement procedures, the burden of PJI will be felt not only by individual patients, but in increased healthcare costs. Current treatment of PJI is inadequate resulting in incredibly high failure rates. This is believed to be largely mediated by the presence of bacterial biofilms. These polymicrobial bacterial colonies form within secreted extracellular matrices, adhering to the implant surface and local tissue. The biofilm architecture is believed to play a complex and critical role in a variety of bacterial processes including nutrient supplementation, metabolism, waste management, and antibiotic and immune resistance. The establishment of these biofilms relies heavily on the quorum sensing communication systems utilized by bacteria. Early stage research into disrupting bacterial communication by targeting quorum sensing show promise for future clinical applications. However, prevention of the biofilm formation via early forced induction of the biofilm forming process remains yet unexplored. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2331-2339, 2018.}, } @article {pmid29662838, year = {2018}, author = {Li, H and Liu, F and Peng, W and Yan, K and Zhao, H and Liu, T and Cheng, H and Chang, P and Yuan, F and Chen, H and Bei, W}, title = {The CpxA/CpxR Two-Component System Affects Biofilm Formation and Virulence in Actinobacillus pleuropneumoniae.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {72}, pmid = {29662838}, issn = {2235-2988}, mesh = {Actinobacillus Infections/microbiology ; Actinobacillus pleuropneumoniae/*genetics/growth & development/*metabolism/pathogenicity ; Animals ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; DNA-Binding Proteins ; Deoxyribonuclease I/analysis ; Disease Models, Animal ; Electrophoretic Mobility Shift Assay ; Escherichia coli/genetics ; Female ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Mice ; Mice, Inbred BALB C ; Mutation ; Operon ; Protein Footprinting ; Protein Kinases/*genetics/*metabolism ; Sigma Factor/genetics/metabolism ; Transcriptome ; Virulence/genetics ; Virulence Factors/*genetics/metabolism ; }, abstract = {Gram-negative bacteria have evolved numerous two-component systems (TCSs) to cope with external environmental changes. The CpxA/CpxR TCS consisting of the kinase CpxA and the regulator CpxR, is known to be involved in the biofilm formation and virulence of Escherichia coli. However, the role of CpxA/CpxR remained unclear in Actinobacillus pleuropneumoniae, a bacterial pathogen that can cause porcine contagious pleuropneumonia (PCP). In this report, we show that CpxA/CpxR contributes to the biofilm formation ability of A. pleuropneumoniae. Furthermore, we demonstrate that CpxA/CpxR plays an important role in the expression of several biofilm-related genes in A. pleuropneumoniae, such as rpoE and pgaC. Furthermore, The results of electrophoretic mobility shift assays (EMSAs) and DNase I footprinting analysis demonstrate that CpxR-P can regulate the expression of the pgaABCD operon through rpoE. In an experimental infection of mice, the animals infected with a cpxA/cpxR mutant exhibited delayed mortality and lower bacterial loads in the lung than those infected with the wildtype bacteria. In conclusion, these results indicate that the CpxA/CpxR TCS plays a contributing role in the biofilm formation and virulence of A. pleuropneumoniae.}, } @article {pmid29661929, year = {2018}, author = {Yamada, KJ and Heim, CE and Aldrich, AL and Gries, CM and Staudacher, AG and Kielian, T}, title = {Arginase-1 Expression in Myeloid Cells Regulates Staphylococcus aureus Planktonic but Not Biofilm Infection.}, journal = {Infection and immunity}, volume = {86}, number = {7}, pages = {}, pmid = {29661929}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Arginase/*physiology ; *Biofilms ; Biogenic Polyamines/physiology ; Catheter-Related Infections ; Female ; Male ; Mice ; Mice, Inbred C57BL ; Myeloid-Derived Suppressor Cells/*physiology ; Nitric Oxide Synthase Type II/analysis ; Plankton/*microbiology ; Staphylococcal Infections/*etiology ; Staphylococcus aureus/*physiology ; }, abstract = {Staphylococcus aureus is a leading cause of device-associated biofilm infections, which represent a serious health care concern based on their chronicity and antibiotic resistance. We previously reported that S. aureus biofilms preferentially recruit myeloid-derived suppressor cells (MDSCs), which promote monocyte and macrophage anti-inflammatory properties. This is associated with increased myeloid arginase-1 (Arg-1) expression, which has been linked to anti-inflammatory and profibrotic activities that are observed during S. aureus biofilm infections. To determine whether MDSCs and macrophages utilize Arg-1 to promote biofilm infection, Arg-1 was deleted in myeloid cells by use of Tie-2[Cre] mice. Despite Arg-1 expression in biofilm-associated myeloid cells, bacterial burdens and leukocyte infiltrates were similar between wild-type (WT) and Arg-1[fl/fl];Tie-2[Cre] conditional knockout (KO) mice from days 3 to 14 postinfection in both orthopedic implant and catheter-associated biofilm models. However, inducible nitric oxide synthase (iNOS) expression was dramatically elevated in biofilm-associated MDSCs from Arg-1[fl/fl];Tie-2[Cre] animals, suggesting a potential Arg-1-independent compensatory mechanism for MDSC-mediated immunomodulation. Treatment of Arg-1[fl/fl];Tie-2[Cre] mice with the iNOS inhibitor N6-(1-iminoethyl)-l-lysine (l-NIL) had no effect on biofilm burdens or immune infiltrates, whereas treatment of WT mice with the Arg-1/ornithine decarboxylase inhibitor difluoromethylornithine (DFMO) increased bacterial titers, but only in the surrounding soft tissues, which possess attributes of a planktonic environment. A role for myeloid-derived Arg-1 in regulating planktonic infection was confirmed using a subcutaneous abscess model, in which S. aureus burdens were significantly increased in Arg-1[fl/fl];Tie-2[Cre] mice compared to those in WT mice. Collectively, these results indicate that the effects of myeloid Arg-1 are context dependent and are manifest during planktonic but not biofilm infection.}, } @article {pmid29659477, year = {2018}, author = {Anderson, MJ and Schaaf, E and Breshears, LM and Wallis, HW and Johnson, JR and Tkaczyk, C and Sellman, BR and Sun, J and Peterson, ML}, title = {Alpha-Toxin Contributes to Biofilm Formation among Staphylococcus aureus Wound Isolates.}, journal = {Toxins}, volume = {10}, number = {4}, pages = {}, pmid = {29659477}, issn = {2072-6651}, support = {UL1 TR000114/TR/NCATS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Toxins ; Biofilms ; Female ; Genotype ; Hemolysin Proteins/*physiology ; Humans ; Mucous Membrane ; Staphylococcus aureus/*physiology ; Swine ; Vagina ; Wounds and Injuries ; }, abstract = {Biofilms complicate treatment of Staphylococcus aureus (SA) wound infections. Previously, we determined alpha-toxin (AT)-promoted SA biofilm formation on mucosal tissue. Therefore, we evaluated SA wound isolates for AT production and biofilm formation on epithelium and assessed the role of AT in biofilm formation. Thirty-eight wound isolates were molecularly typed by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (ST), and spa typing. We measured biofilm formation of these SA isolates in vitro and ex vivo and quantified ex vivo AT production. We also investigated the effect of an anti-AT monoclonal antibody (MEDI4893*) on ex vivo biofilm formation by methicillin-resistant SA (USA 300 LAC) and tested whether purified AT rescued the biofilm defect of hla mutant SA strains. The predominant PFGE/ST combinations were USA100/ST5 (50%) and USA300/ST8 (33%) for methicillin-resistant SA (MRSA, n = 18), and USA200/ST30 (20%) for methicillin-susceptible SA (MSSA, n = 20). Ex vivo AT production correlated significantly with ex vivo SA wound isolate biofilm formation. Anti-alpha-toxin monoclonal antibody (MEDI4893*) prevented ex vivo biofilm formation by MRSA USA300 strain LAC. Wild-type AT rescued the ex vivo biofilm defect of non-AT producing SA strains. These findings provide evidence that AT plays a role in SA biofilm formation on epithelial surfaces and suggest that neutralization of AT may be useful in preventing and treating SA infections.}, } @article {pmid29657925, year = {2018}, author = {Poursina, F and Sepehrpour, S and Mobasherizadeh, S}, title = {Biofilm Formation in Nonmultidrug-resistant Escherichia coli Isolated from Patients with Urinary Tract Infection in Isfahan, Iran.}, journal = {Advanced biomedical research}, volume = {7}, number = {}, pages = {40}, pmid = {29657925}, issn = {2277-9175}, abstract = {BACKGROUND: Escherichia coli is a Gram-negative, opportunistic human pathogen in which increasing antibiotic resistance is a great concern for continued human survival. Although biofilm formation is a mechanism that helps E. coli to survive in unfavorable conditions, according to the importance of biofilm formation in developing the antibiotic resistance here, we studied the relation between antibiotic resistance and in vitro qualitative rating method biofilm formation in E. coli isolated from patients with urinary tract infection (UTI).

MATERIALS AND METHODS: The clinical isolates of E. coli (n = 100) were collected from urine of patients with UTI attending Isfahan Alzahra hospital. The strains were confirmed as E. coli using biochemical tests and molecular method. The Kirby-Bauer disk diffusion tests were done according to the Clinical and Laboratory Standards Institute protocol, and the biofilm synthesis was performed by microplate method. The binary logistic test was applied and P < 0.05 was considered statistically significant.

RESULTS: Our results showed a high outbreak of multidrug-resistant (MDR) E. coli strains (73%) and the highest resistance was observed toward ampicillin. The prevalence of biofilm producer isolates was 80% that 29% produced strong biofilm. The distribution of non-MDR isolates was high among strong biofilm producers, which shows a significant negative correlation between biofilm production and MDR pattern (P < 0.001).

CONCLUSIONS: We found a negative correlation between MDR phenotype and biofilm formation capacity. This transmits the concept that more antibiotic susceptibility of strong biofilm producers may be due to the reduced exposure to multiple antibiotics.}, } @article {pmid29657522, year = {2018}, author = {Giacaman, RA and Pailahual, V and Díaz-Garrido, N}, title = {Cariogenicity induced by commercial carbonated beverages in an experimental biofilm-caries model.}, journal = {European journal of dentistry}, volume = {12}, number = {1}, pages = {27-35}, pmid = {29657522}, issn = {1305-7456}, abstract = {OBJECTIVES: Frequent consumption of sugars-containing carbonated beverages has been associated with caries, but the consequences on the dental biofilm remain unclear. The aim was to evaluate the effect of commercial carbonated beverages and their sugar-free version on enamel and dentine demineralization and on the cariogenic properties of Streptococcus mutans biofilms.

MATERIALS AND METHODS: Biofilms of S. mutans UA159 were grown on enamel and dentin slabs and exposed 3 times/day for 5 min, to a commercial cola or orange-flavored carbonated beverage or to their sugar-free version. Biofilms/slabs were recovered to assess biomass, viable microorganisms, protein content and polysaccharides. Demineralization was estimated by the variation of Knoop surface microhardness.

RESULTS: Exposures to the biofilm with sugars-containing carbonated beverages resulted in similar biomass, viable microorganisms, proteins, and polysaccharides than sucrose (P < 0.05). The sugar-free cola and orange-flavored drink showed lower effect on the biofilm, as compared with sucrose or their sugared version (P < 0.05). All of the products tested, included the sugar-free, showed higher demineralization than the negative control (P < 0.05).

CONCLUSIONS: Sugars-containing carbonated beverages enhance cariogenic activity of S. mutans biofilms, comparable with sucrose. Sugar-free carbonated beverages also have a high demineralizing potential, without affecting biofilm properties.}, } @article {pmid29656577, year = {2018}, author = {Manoharan, RK and Lee, JH and Lee, J}, title = {Efficacy of 7-benzyloxyindole and other halogenated indoles to inhibit Candida albicans biofilm and hyphal formation.}, journal = {Microbial biotechnology}, volume = {11}, number = {6}, pages = {1060-1069}, pmid = {29656577}, issn = {1751-7915}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Caenorhabditis elegans ; Candida albicans/*drug effects/genetics/pathogenicity/physiology ; Candidiasis/microbiology ; Fungal Proteins/genetics/metabolism ; Gene Expression Profiling ; Halogenation ; Humans ; Hyphae/drug effects/pathogenicity/physiology ; Indoles/chemistry/*pharmacology ; Virulence/drug effects ; }, abstract = {Certain pathogenic bacteria and yeast form biofilms on biotic and abiotic surfaces including medical devices and implants. Hence, the development of antibiofilm coating materials becomes relevant. The virulence of those colonizing pathogens can be reduced by inhibiting biofilm formation rather than killing pathogens using excessive amounts of antimicrobials, which is touted as one of the main reasons for the development of drug resistance. Candida albicans is an opportunistic fungal pathogen, and the transition of yeast cells to hyphal cells is believed to be a crucial virulence factor. Previous studies have shown that indole and its derivatives possess antivirulence properties against various bacterial pathogens. In this study, we used various indole derivatives to investigate biofilm-inhibiting activity against C. albicans. Our study revealed that 7-benzyloxyindole, 4-fluoroindole and 5-iodoindole effectively inhibited biofilm formation compared to the antifungal agent fluconazole. Particularly, 7-benzyloxyindole at 0.02 mM (4.5 μg ml[-1]) significantly reduced C. albicans biofilm formation, but had no effect on planktonic cells, and this finding was confirmed by a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and three-dimensional confocal laser scanning microscopy. Scanning electron microscopy analyses revealed that 7-benzyloxyindole effectively inhibited hyphal formation, which explains biofilm inhibition. Transcriptomic analysis showed that 7-benzyloxyindole downregulated the expressions of several hypha/biofilm-related genes (ALS3, ECE1, HWP1 and RBT1). A C. albicans-infected Caenorhabditis elegans model system was used to confirm the antivirulence efficacy of 7-benzyloxyindole.}, } @article {pmid29655267, year = {2018}, author = {Brun, P and Bernabè, G and Marchiori, C and Scarpa, M and Zuin, M and Cavazzana, R and Zaniol, B and Martines, E}, title = {Antibacterial efficacy and mechanisms of action of low power atmospheric pressure cold plasma: membrane permeability, biofilm penetration and antimicrobial sensitization.}, journal = {Journal of applied microbiology}, volume = {125}, number = {2}, pages = {398-408}, doi = {10.1111/jam.13780}, pmid = {29655267}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/*pharmacology ; Atmospheric Pressure ; Biofilms/*drug effects ; Cell Membrane Permeability/*drug effects ; Drug Synergism ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Plasma Gases/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {AIM: The objective of this study was to determine the efficacy and mechanisms of inactivation of two clinically relevant ESKAPE bacteria namely Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus by atmospheric pressure cold plasma.

METHODS AND RESULTS: Plasma was generated between two brass grids by applying a radiofrequency electric field to a flow of helium. Intracellular generation of reactive species, alterations in cell membrane, and inactivation of bacteria in planktonic or biofilm growth were studied. Results were compared with commonly used antimicrobial drugs. Plasma exposure generated reactive oxygen and nitrogen species in bacteria, disrupted membrane integrity and reduced bacterial load. The efficacy in bacterial inactivation was comparable to antibiotics but exhibited a quicker killing rate. The antibacterial effect of plasma synergistically increased in association with antibiotics and did not diminish over repeated exposures, suggesting no development in bacterial resistance.

CONCLUSIONS: Through generation of reactive species, cold plasma altered cell membrane and effectively inactivated clinically important bacteria, both in suspension and in biofilms.

As cold plasma damages different targets in bacterial cells, it emerges as an effective strategy used alone or in combination with antimicrobial drugs to control microbial infections and prevent the selection of resistant bacterial strains.}, } @article {pmid29654902, year = {2018}, author = {Beshiru, A and Igbinosa, EO}, title = {Characterization of extracellular virulence properties and biofilm-formation capacity of Vibrio species recovered from ready-to-eat (RTE) shrimps.}, journal = {Microbial pathogenesis}, volume = {119}, number = {}, pages = {93-102}, doi = {10.1016/j.micpath.2018.04.015}, pmid = {29654902}, issn = {1096-1208}, mesh = {Animals ; Bacterial Adhesion ; Bacterial Typing Techniques ; Biofilms/*growth & development ; DNA, Bacterial ; Hydrophobic and Hydrophilic Interactions ; Nigeria ; Penaeidae/*microbiology ; Seafood/*microbiology ; Shellfish/*microbiology ; Species Specificity ; Vibrio/classification/isolation & purification/*metabolism/*pathogenicity ; Virulence ; Virulence Factors/*metabolism ; }, abstract = {In this study, we evaluated the virulence factor production, biofilm-forming ability and cell surface properties of ready-to-eat shrimps associated vibrios strains. A total of 1440 ready-to-eat (RTE) shrimp samples were purchased from open markets in southern Nigeria, from November 2016 to October 2017. Biofilm formation was carried out using the microtitre plate method. Cell-to-cell adhesion of Vibrio species was assessed via surface hydrophobicity using the bacterial adherence to hydrocarbons (BATH) and salting aggregation technique, autoaggregation and coaggregation assay. The virulence potential of the identified 120 Vibrio strains includes haemolysis 107 (89.17%), lipase 106 (88.33%), protease 108 (90%), gelatinase 111 (92.5%), the presence of surface-layer (S-layer) 109 (90.8%) and DNA degrading activity 107 (89.17%). Biofilm formation at 30 °C tryptone soy broth in dynamic conditions revealed total biofilm producers for the Vibrio species as follows: V. parahaemolyticus (95.65%), V. vulnificus (92.86%), V. fluvialis (91.67%), V. alginolyticus (87.5%), V. cholerae (100%), V. mimicus (90%), V. harveyi (66.7%), and other Vibrio spp. (84%). A total of 50 biofilm producing vibrios using BATH technique include 49 (98%) hydrophilic and 1 (2%) moderately hydrophobic. Using the modified salting aggregation technique, 50 (100%) was characterized as hydrophilic. Autoaggregation index for the 12 biofilms producing Vibrio strains ranged from 11.6 to 41.3%, while the autoaggregation index for the 12 test bacteria ranged from 26.2 to 71.3%. Coaggregation between the 12 test bacteria with the 12 Vibrio strains ranged from 9.3 to 78.5%. However most vibrios in this study were hydrophilic, their hydrophilic potential is important for their capability to autoaggregate and coaggregate. Findings on the specific process by which virulent Vibrio spp. form biofilm and adhere to shrimp surface as attached plankton may assist in monitoring epidemics of the pathogen.}, } @article {pmid29653478, year = {2018}, author = {Sritharadol, R and Hamada, M and Kimura, S and Ishii, Y and Srichana, T and Tateda, K}, title = {Mupirocin at Subinhibitory Concentrations Induces Biofilm Formation in Staphylococcus aureus.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {24}, number = {9}, pages = {1249-1258}, doi = {10.1089/mdr.2017.0290}, pmid = {29653478}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Down-Regulation/drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Mupirocin/*pharmacology ; Plankton/microbiology ; Up-Regulation/drug effects ; }, abstract = {OBJECTIVES: Mupirocin is a useful antibiotic against superficial skin infections. We compared the impact of mupirocin with a cephalosporin, a fluoroquinolone, an aminoglycoside, and a macrolide on planktonic cell growth and biofilm formation of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA).

MATERIALS AND METHODS: Minimum inhibitory concentration (MIC) of mupirocin was determined against S. aureus strains used in this study. Biofilm formation of S. aureus strains exposed to mupirocin was quantified by crystal violet staining assay. Moreover, biofilm structure and viability of the biofilm cells were visualized by Live/Dead staining assay. Biofilm-related gene expression was investigated by quantitative real-time PCR.

RESULTS: MRSA USA300 clone was resistant to mupirocin with MIC of 1,024 mg/L, while MRSA ATCC-43300 and MSSA ATCC-29213 were susceptible with MICs of 0.03 mg/L. Planktonic cell growth of the S. aureus strains was inhibited by mupirocin in a dose-dependent manner. However, some of the low concentrations of mupirocin less than the MICs promoted biofilm formation. Confocal laser scanning microscopy of the biofilm structures and cell viabilities showed established biofilms of slightly higher cell density in the mupirocin treated groups, especially in the MRSA USA300 clone. Gene expression of RNAIII in planktonic cells and biofilms of MRSA USA300 clone showed the highest upregulation after initial exposure to sub-MIC of mupirocin followed by downregulation, whereas the other antibiotics showed various fluctuations.

CONCLUSION: The results showed that subinhibitory concentrations of mupirocin promoted biofilm formation of S. aureus, in particular the MRSA USA300 clone.}, } @article {pmid29653332, year = {2018}, author = {Huang, Y and Zheng, Y and Li, J and Liao, Q and Fu, Q and Xia, A and Fu, J and Sun, Y}, title = {Enhancing microalgae biofilm formation and growth by fabricating microgrooves onto the substrate surface.}, journal = {Bioresource technology}, volume = {261}, number = {}, pages = {36-43}, doi = {10.1016/j.biortech.2018.03.139}, pmid = {29653332}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; *Microalgae ; Stress, Mechanical ; Surface Properties ; }, abstract = {Attachment of cells to substrate surface is the premise for biofilm formation. To shelter microalgae cells from fluid shear stress and offer larger areas for microalgae attachment, the inerratic microgrooves, which can act as anchor points that offer larger areas for microalgae attachment and induce vortex to protect cells from hydraulic shear stress, were designed and fabricated into substrate surface. The results indicated that the shear stress on the surface with V-grooves was weaker than that on the surface with U-grooves, and 45° V-grooves with the width of 200 μm were benefit for cells attachment. The initial attachment time was shortened to 50 min under the hydraulic shear stress of 0.02 Pa compared to that of 135 min on the surface without microgrooves. Subsequently, the biofilm biomass concentration on the surface with 45° V-grooves increased by 14.29% to 165.84 g m[-2] compared with that on flat substrates.}, } @article {pmid29653313, year = {2018}, author = {Pires, JG and Zabini, SS and Braga, AS and de Cássia Fabris, R and de Andrade, FB and de Oliveira, RC and Magalhães, AC}, title = {Hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on Streptococcus mutans biofilm and tooth demineralization.}, journal = {Archives of oral biology}, volume = {91}, number = {}, pages = {17-22}, doi = {10.1016/j.archoralbio.2018.04.005}, pmid = {29653313}, issn = {1879-1506}, mesh = {Anacardiaceae/*chemistry ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cattle ; Dental Caries/prevention & control ; Dental Enamel/drug effects/pathology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Phytotherapy ; Plant Extracts/*pharmacology ; Plant Leaves/*chemistry ; Saliva ; Streptococcus mutans/*drug effects ; Tooth Demineralization/*prevention & control ; }, abstract = {OBJECTIVES: This study evaluated the effect of the hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves (alone or combined) on the viability of Streptococcus mutans biofilm and on the prevention of enamel demineralization.

METHODS: Strain of S. mutans (ATCC 21175) was reactivated in BHI broth. Minimum inhibitory concentration, minimum bactericidal concentration, minimum inhibition biofilm concentration and minimum eradication biofilm concentration were determined in order to choose the concentrations to be tested under biofilm model. S. mutans biofilm (5 × 10[5] CFU/ml) was produced on bovine enamel, using McBain saliva under 0.2% sucrose exposure, for 3 days. The biofilm was daily treated with the extracts for 1 min. The biofilm viability was tested by fluorescence and the enamel demineralization was measured using TMR.

RESULTS: Myracrodruon urundeuva All. (Isolated or combined) at the concentrationsc ≥0.625 mg/ml was able to reduce bacteria viability, while Qualea Grandflora Mart. alone had antimicrobial effect at 5 mg/ml only (p < 0.05). On the other hand, none of the extracts were able to reduce enamel demineralization.

CONCLUSIONS: The hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves (isolated or combined) have antimicrobial action; however, they do not prevent enamel caries under S. mutans biofilm model.}, } @article {pmid29653134, year = {2018}, author = {Alonso, B and Pérez-Granda, MJ and Rodríguez-Huerta, A and Rodríguez, C and Bouza, E and Guembe, M}, title = {The optimal ethanol lock therapy regimen for treatment of biofilm-associated catheter infections: an in-vitro study.}, journal = {The Journal of hospital infection}, volume = {100}, number = {3}, pages = {e187-e195}, doi = {10.1016/j.jhin.2018.04.007}, pmid = {29653134}, issn = {1532-2939}, mesh = {Bacteria/drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Candida/drug effects/growth & development ; Catheter-Related Infections/*prevention & control ; Catheters/*microbiology ; Disinfectants/*administration & dosage ; Ethanol/*administration & dosage ; Heparin/administration & dosage ; Humans ; Infection Control/*methods ; Metabolism/drug effects ; Staining and Labeling/methods ; Tetrazolium Salts/metabolism ; }, abstract = {BACKGROUND: Ethanol-based lock therapy (LT) solutions are used as an alternative to antibiotics for the conservative management of catheter-related bloodstream infection. However, no clear consensus on regimen or dose has been reached.

AIM: To find the ethanol-based lock solution containing a sufficiently low concentration of ethanol for reduction of the metabolic activity of bacterial and fungal biofilms.

METHODS: Using an in-vitro model, three concentrations of ethanol (25%, 40%, 70%) were tested, with and without 60 IU of heparin, at six different time-points and against 24 h preformed biofilms of Staphylococcus aureus ATCC29213, Staphylococcus epidermidis (clinical isolate), Enterococcus faecalis ATCC33186, Candida albicans ATCC14058, and Escherichia coli ATCC25922. The reduction in the metabolic activity of the biofilm was measured using the tetrazolium salt assay and LT was considered to be successful when metabolic activity fell by >90%. Regrowth inhibition was then tested within 24 h and seven days after each LT regimen only at the ethanol concentration of the most successful LT regimen.

FINDINGS: The most successful LT was achieved with 40% ethanol + 60 IU of heparin only at 24, 72, and 24 h for seven-day regimens (P < 0.05). However, none of the regimens reached 45% RI within seven days of therapy.

CONCLUSION: According to our in-vitro data, an ethanol-based lock solution with 40% ethanol + 60 IU heparin administered daily for 72 h is sufficient to almost eradicate the metabolic activity of bacterial and fungal biofilms. Future studies are needed to study cell regrowth after LT.}, } @article {pmid29651836, year = {2018}, author = {Zhao, Y and Dai, X and Wei, X and Yu, Y and Chen, X and Zhang, X and Li, C}, title = {Near-Infrared Light-Activated Thermosensitive Liposomes as Efficient Agents for Photothermal and Antibiotic Synergistic Therapy of Bacterial Biofilm.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {17}, pages = {14426-14437}, doi = {10.1021/acsami.8b01327}, pmid = {29651836}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Infrared Rays ; Liposomes ; Pseudomonas aeruginosa ; }, abstract = {Biofilm is closely related to chronic infections and is difficult to eradicate. Development of effective therapy strategies to control biofilm infection is still challenging. Aiming at biofilm architecture, we designed and prepared near-infrared-activated thermosensitive liposomes with photothermal and antibiotic synergistic therapy capacity to eliminate Pseudomonas aeruginosa biofilm. The liposomes with positive charge and small size aided to enter the biofilm microchannels and locally released antibiotics in infection site. The liposomes could remain stable at 37 °C and release about 80% antibiotics over 45 °C. The biofilm dispersion rate was up to 80%, which was a 7- to 8-fold rise compared to excess antibiotic alone, indicating that the localized antibiotic release and photothermal co-therapy improved the antimicrobial efficiency. In vivo drug-loaded liposomes in treating P. aeruginosa-induced abscess exhibited an outstanding therapeutic effect. Furthermore, photothermal treatment could stimulate the expression of bcl2-associated athanogene 3 to prevent normal tissue from thermal damage. The near-infrared-activated nanoparticle carriers had the tremendous therapeutic potential to dramatically enhance the efficacy of antibiotics through thermos-triggered drug release and photothermal therapy.}, } @article {pmid29651554, year = {2018}, author = {de Grandi, AZ and Pinto, UM and Destro, MT}, title = {Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface.}, journal = {World journal of microbiology & biotechnology}, volume = {34}, number = {4}, pages = {61}, pmid = {29651554}, issn = {1573-0972}, support = {457794/2014-3//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 2013/07914-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2011/18033-7//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; Fellowship//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Coculture Techniques ; Colony Count, Microbial ; Culture Media/chemistry ; Escherichia coli/*physiology ; Food-Processing Industry ; Gene Expression Profiling ; Listeria monocytogenes/genetics/*physiology ; Microbial Interactions/*physiology ; Mutation ; Peptide Termination Factors ; Sigma Factor/genetics ; *Stainless Steel ; Virulence ; }, abstract = {Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σ[B], in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.}, } @article {pmid29651297, year = {2018}, author = {Sahu, SK and Zheng, P and Yao, N}, title = {Niclosamide Blocks Rice Leaf Blight by Inhibiting Biofilm Formation of Xanthomonas oryzae.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {408}, pmid = {29651297}, issn = {1664-462X}, abstract = {Rice (Oryza sativa) is the leading source of nutrition for more than half of the world's population, and by far it is the most important commercial food crop. But, its growth and production are significantly hampered by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) which causes leaf blight disease. Earlier studies have reported the antibacterial ability of FDA-approved niclosamide drug against Xoo. However, the underlying mechanism by which niclosamide blocks the growth of Xoo remained elusive. In the present study, by employing the microbiological, microscopical, molecular, bioinformatics and analytical tools we found that niclosamide can directly inhibit the growth of the Xoo by hampering the biofilm formation and the production of xanthomonadin and exopolysaccharide substances (EPS) required for relentless growth and virulence of Xoo. Interestingly, niclosamide was found to specifically suppress the growth of Xoo without affecting other bacteria like Escherichia coli. Our electron microscopic observations disclosed that niclosamide disrupts the membrane permeability of Xoo and causes the release of intracellular components. Similarly, the molecular docking analysis disclosed the molecular interaction of niclosamide with the biofilm, virulence and quorum sensing related proteins, which was further substantiated by relative gene expression analysis where niclosamide was found to significantly downregulate the expression of these key regulatory genes. In addition, considerable changes in chemical structures were detected by Fourier Transform Infrared Spectroscopy (FTIR) in response to niclosamide treatment. Overall, our findings advocate the utilization of niclosamide as a safe and potent alternative antibacterial compound to control bacterial blight disease in rice.}, } @article {pmid29649240, year = {2018}, author = {Oyebamiji, OK and Wilkinson, DJ and Jayathilake, PG and Rushton, SP and Bridgens, B and Li, B and Zuliani, P}, title = {A Bayesian approach to modelling the impact of hydrodynamic shear stress on biofilm deformation.}, journal = {PloS one}, volume = {13}, number = {4}, pages = {e0195484}, pmid = {29649240}, issn = {1932-6203}, mesh = {Bayes Theorem ; *Biofilms ; *Hydrodynamics ; *Models, Statistical ; Poisson Distribution ; *Shear Strength ; *Stress, Mechanical ; Wastewater/microbiology ; }, abstract = {We investigate the feasibility of using a surrogate-based method to emulate the deformation and detachment behaviour of a biofilm in response to hydrodynamic shear stress. The influence of shear force, growth rate and viscoelastic parameters on the patterns of growth, structure and resulting shape of microbial biofilms was examined. We develop a statistical modelling approach to this problem, using combination of Bayesian Poisson regression and dynamic linear models for the emulation. We observe that the hydrodynamic shear force affects biofilm deformation in line with some literature. Sensitivity results also showed that the expected number of shear events, shear flow, yield coefficient for heterotrophic bacteria and extracellular polymeric substance (EPS) stiffness per unit EPS mass are the four principal mechanisms governing the bacteria detachment in this study. The sensitivity of the model parameters is temporally dynamic, emphasising the significance of conducting the sensitivity analysis across multiple time points. The surrogate models are shown to perform well, and produced ≈ 480 fold increase in computational efficiency. We conclude that a surrogate-based approach is effective, and resulting biofilm structure is determined primarily by a balance between bacteria growth, viscoelastic parameters and applied shear stress.}, } @article {pmid29649179, year = {2018}, author = {Mihai, MM and Preda, M and Lungu, I and Gestal, MC and Popa, MI and Holban, AM}, title = {Nanocoatings for Chronic Wound Repair-Modulation of Microbial Colonization and Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {19}, number = {4}, pages = {}, pmid = {29649179}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology/therapeutic use ; Bacterial Infections/*therapy ; Biofilms/*drug effects ; Debridement ; Humans ; Nanostructures/chemistry/therapeutic use ; Probiotics ; *Wound Healing ; Wound Infection/*microbiology/therapy ; }, abstract = {Wound healing involves a complex interaction between immunity and other natural host processes, and to succeed it requires a well-defined cascade of events. Chronic wound infections can be mono- or polymicrobial but their major characteristic is their ability to develop a biofilm. A biofilm reduces the effectiveness of treatment and increases resistance. A biofilm is an ecosystem on its own, enabling the bacteria and the host to establish different social interactions, such as competition or cooperation. With an increasing incidence of chronic wounds and, implicitly, of chronic biofilm infections, there is a need for alternative therapeutic agents. Nanotechnology shows promising openings, either by the intrinsic antimicrobial properties of nanoparticles or their function as drug carriers. Nanoparticles and nanostructured coatings can be active at low concentrations toward a large variety of infectious agents; thus, they are unlikely to elicit emergence of resistance. Nanoparticles might contribute to the modulation of microbial colonization and biofilm formation in wounds. This comprehensive review comprises the pathogenesis of chronic wounds, the role of chronic wound colonization and infection in the healing process, the conventional and alternative topical therapeutic approaches designed to combat infection and stimulate healing, as well as revolutionizing therapies such as nanotechnology-based wound healing approaches.}, } @article {pmid29644088, year = {2018}, author = {Ren, Q and Li, Z and Ding, L and Wang, X and Niu, Y and Qin, X and Zhou, X and Zhang, L}, title = {Anti-biofilm and remineralization effects of chitosan hydrogel containing amelogenin-derived peptide on initial caries lesions.}, journal = {Regenerative biomaterials}, volume = {5}, number = {2}, pages = {69-76}, pmid = {29644088}, issn = {2056-3418}, abstract = {In this study, we have designed a more clinically powerful anti-caries treatment by applying the amelogenin-derived peptide QP5 to the antibacterial carrier material chitosan in a hydrogel (CS-QP5 hydrogel), and characterized its effects on the inhibition of a cariogenic biofilm and the promotion of the remineralization of the initial caries lesions. The results indicated that the CS-QP5 hydrogel sustainably inhibited the growth of the Streptococcus mutans biofilm, lactic acid production and the metabolic activity over a prolonged period of time. Moreover, the CS-QP5 hydrogel promoted the remineralization of early enamel lesions, which were indicated by surface micro-hardness (, polarized light microscopy and transverse microradiography. In conclusion, the CS-QP5 hydrogel shows good potential for caries control in the clinic because of its antibacterial effects as well as the remineralization of initial enamel carious lesions even in a biofilm model over a prolonged period of time.}, } @article {pmid29638121, year = {2018}, author = {Garrison, AT and Abouelhassan, Y and Kallifidas, D and Tan, H and Kim, YS and Jin, S and Luesch, H and Huigens, RW}, title = {An Efficient Buchwald-Hartwig/Reductive Cyclization for the Scaffold Diversification of Halogenated Phenazines: Potent Antibacterial Targeting, Biofilm Eradication, and Prodrug Exploration.}, journal = {Journal of medicinal chemistry}, volume = {61}, number = {9}, pages = {3962-3983}, doi = {10.1021/acs.jmedchem.7b01903}, pmid = {29638121}, issn = {1520-4804}, support = {S10 OD021758/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Cyclization ; *Halogenation ; HeLa Cells ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Microbial Sensitivity Tests ; Phenazines/*chemistry/*pharmacology ; }, abstract = {Bacterial biofilms are surface-attached communities comprised of nonreplicating persister cells housed within a protective extracellular matrix. Biofilms display tolerance toward conventional antibiotics, occur in ∼80% of infections, and lead to >500000 deaths annually. We recently identified halogenated phenazine (HP) analogues which demonstrate biofilm-eradicating activities against priority pathogens; however, the synthesis of phenazines presents limitations. Herein, we report a refined HP synthesis which expedited the identification of improved biofilm-eradicating agents. 1-Methoxyphenazine scaffolds were generated through a Buchwald-Hartwig cross-coupling (70% average yield) and subsequent reductive cyclization (68% average yield), expediting the discovery of potent biofilm-eradicating HPs (e.g., 61: MRSA BAA-1707 MBEC = 4.69 μM). We also developed bacterial-selective prodrugs (reductively activated quinone-alkyloxycarbonyloxymethyl moiety) to afford HP 87, which demonstrated excellent antibacterial and biofilm eradication activities against MRSA BAA-1707 (MIC = 0.15 μM, MBEC = 12.5 μM). Furthermore, active HPs herein exhibit negligible cytotoxic or hemolytic effects, highlighting their potential to target biofilms.}, } @article {pmid29637531, year = {2018}, author = {Jani, S}, title = {Erratum to: Visualizing Chemoattraction of Planktonic Cells to a Biofilm.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1729}, number = {}, pages = {E1}, doi = {10.1007/978-1-4939-7577-8_30}, pmid = {29637531}, issn = {1940-6029}, } @article {pmid29636741, year = {2018}, author = {Broussou, DC and Lacroix, MZ and Toutain, PL and Woehrlé, F and El Garch, F and Bousquet-Melou, A and Ferran, AA}, title = {Differential Activity of the Combination of Vancomycin and Amikacin on Planktonic vs. Biofilm-Growing Staphylococcus aureus Bacteria in a Hollow Fiber Infection Model.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {572}, pmid = {29636741}, issn = {1664-302X}, abstract = {Combining currently available antibiotics to optimize their use is a promising strategy to reduce treatment failures against biofilm-associated infections. Nevertheless, most assays of such combinations have been performed in vitro on planktonic bacteria exposed to constant concentrations of antibiotics over only 24 h and the synergistic effects obtained under these conditions do not necessarily predict the behavior of chronic clinical infections associated with biofilms. To improve the predictivity of in vitro combination assays for bacterial biofilms, we first adapted a previously described Hollow-fiber (HF) infection model by allowing a Staphylococcus aureus biofilm to form before drug exposure. We then mimicked different concentration profiles of amikacin and vancomycin, similar to the free plasma concentration profiles that would be observed in patients treated daily over 5 days. We assessed the ability of the two drugs, alone or in combination, to reduce planktonic and biofilm-embedded bacterial populations, and to prevent the selection of resistance within these populations. Although neither amikacin nor vancomycin exhibited any bactericidal activity on S. aureus in monotherapy, the combination had a synergistic effect and significantly reduced the planktonic bacterial population by -3.0 to -6.0 log10 CFU/mL. In parallel, no obvious advantage of the combination, as compared to amikacin alone, was demonstrated on biofilm-embedded bacteria for which the addition of vancomycin to amikacin only conferred a further maximum reduction of 0.3 log10 CFU/mL. No resistance to vancomycin was ever found whereas a few bacteria less-susceptible to amikacin were systematically detected before treatment. These resistant bacteria, which were rapidly amplified by exposure to amikacin alone, could be maintained at a low level in the biofilm population and even suppressed in the planktonic population by adding vancomycin. In conclusion, by adapting the HF model, we were able to demonstrate the different bactericidal activities of the vancomycin and amikacin combination on planktonic and biofilm-embedded bacterial populations, suggesting that, for biofilm-associated infections, the efficacy of this combination would not be much greater than with amikacin monotherapy. However, adding vancomycin could reduce possible resistance to amikacin and provide a relevant strategy to prevent the selection of antibiotic-resistant bacteria during treatments.}, } @article {pmid29636440, year = {2018}, author = {Tseng, BS and Reichhardt, C and Merrihew, GE and Araujo-Hernandez, SA and Harrison, JJ and MacCoss, MJ and Parsek, MR}, title = {A Biofilm Matrix-Associated Protease Inhibitor Protects Pseudomonas aeruginosa from Proteolytic Attack.}, journal = {mBio}, volume = {9}, number = {2}, pages = {}, pmid = {29636440}, issn = {2150-7511}, support = {P41 GM103533/GM/NIGMS NIH HHS/United States ; P30 DK089507/DK/NIDDK NIH HHS/United States ; //CIHR/Canada ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; K22 AI121097/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Biofilms/*growth & development ; Extracellular Polymeric Substance Matrix/*chemistry ; Leukocyte Elastase/*antagonists & inhibitors ; Microbial Viability ; Periplasmic Proteins/*analysis/metabolism ; Pseudomonas aeruginosa/metabolism/*physiology ; }, abstract = {Pseudomonas aeruginosa produces an extracellular biofilm matrix that consists of nucleic acids, exopolysaccharides, lipid vesicles, and proteins. In general, the protein component of the biofilm matrix is poorly defined and understudied relative to the other major matrix constituents. While matrix proteins have been suggested to provide many functions to the biofilm, only proteins that play a structural role have been characterized thus far. Here we identify proteins enriched in the matrix of P. aeruginosa biofilms. We then focused on a candidate matrix protein, the serine protease inhibitor ecotin (PA2755). This protein is able to inhibit neutrophil elastase, a bactericidal enzyme produced by the host immune system during P. aeruginosa biofilm infections. We show that ecotin binds to the key biofilm matrix exopolysaccharide Psl and that it can inhibit neutrophil elastase when associated with Psl. Finally, we show that ecotin protects both planktonic and biofilm P. aeruginosa cells from neutrophil elastase-mediated killing. This may represent a novel mechanism of protection for biofilms to increase their tolerance against the innate immune response.IMPORTANCE Proteins associated with the extracellular matrix of bacterial aggregates called biofilms have long been suggested to provide many important functions to the community. To date, however, only proteins that provide structural roles have been described, and few matrix-associated proteins have been identified. We developed a method to identify matrix proteins and characterized one. We show that this protein, when associated with the biofilm matrix, can inhibit a bactericidal enzyme produced by the immune system during infection and protect biofilm cells from death induced by the enzyme. This may represent a novel mechanism of protection for biofilms, further increasing their tolerance against the immune response. Together, our results are the first to show a nonstructural function for a confirmed matrix-interacting protein.}, } @article {pmid29636430, year = {2018}, author = {Keogh, D and Lam, LN and Doyle, LE and Matysik, A and Pavagadhi, S and Umashankar, S and Low, PM and Dale, JL and Song, Y and Ng, SP and Boothroyd, CB and Dunny, GM and Swarup, S and Williams, RBH and Marsili, E and Kline, KA}, title = {Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism.}, journal = {mBio}, volume = {9}, number = {2}, pages = {}, pmid = {29636430}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; *Electron Transport ; Energy Metabolism ; Enterococcus faecalis/growth & development/metabolism/*physiology ; Iron/*metabolism ; L-Lactate Dehydrogenase/metabolism ; }, abstract = {Enterococci are important human commensals and significant opportunistic pathogens. Biofilm-related enterococcal infections, such as endocarditis, urinary tract infections, wound and surgical site infections, and medical device-associated infections, often become chronic upon the formation of biofilm. The biofilm matrix establishes properties that distinguish this state from free-living bacterial cells and increase tolerance to antimicrobial interventions. The metabolic versatility of the enterococci is reflected in the diversity and complexity of environments and communities in which they thrive. Understanding metabolic factors governing colonization and persistence in different host niches can reveal factors influencing the transition to biofilm pathogenicity. Here, we report a form of iron-dependent metabolism for Enterococcus faecalis where, in the absence of heme, extracellular electron transfer (EET) and increased ATP production augment biofilm growth. We observe alterations in biofilm matrix depth and composition during iron-augmented biofilm growth. We show that the ldh gene encoding l-lactate dehydrogenase is required for iron-augmented energy production and biofilm formation and promotes EET.IMPORTANCE Bacterial metabolic versatility can often influence the outcome of host-pathogen interactions, yet causes of metabolic shifts are difficult to resolve. The bacterial biofilm matrix provides the structural and functional support that distinguishes this state from free-living bacterial cells. Here, we show that the biofilm matrix can immobilize iron, providing access to this growth-promoting resource which is otherwise inaccessible in the planktonic state. Our data show that in the absence of heme, Enterococcus faecalis l-lactate dehydrogenase promotes EET and uses matrix-associated iron to carry out EET. Therefore, the presence of iron within the biofilm matrix leads to enhanced biofilm growth.}, } @article {pmid29635622, year = {2018}, author = {Boles, LR and Awais, R and Beenken, KE and Smeltzer, MS and Haggard, WO and Jessica, AJ}, title = {Local Delivery of Amikacin and Vancomycin from Chitosan Sponges Prevent Polymicrobial Implant-Associated Biofilm.}, journal = {Military medicine}, volume = {183}, number = {suppl_1}, pages = {459-465}, doi = {10.1093/milmed/usx161}, pmid = {29635622}, issn = {1930-613X}, mesh = {Amikacin/*administration & dosage/therapeutic use ; Animals ; Anti-Bacterial Agents/administration & dosage/therapeutic use ; Biofilms/drug effects ; Chitosan/*pharmacology/therapeutic use ; Coinfection/drug therapy/*prevention & control ; Disease Models, Animal ; Mice ; Microbial Sensitivity Tests/methods ; Vancomycin/*administration & dosage/therapeutic use ; }, abstract = {Military personnel have high risk for infection, particularly those with combat-related extremity trauma. Administration of multiple or broad-spectrum antibiotics provides clinicians with a strategy for preventing biofilm-based medical device infections. Selection of effective antibiotic combinations based on common pathogens may be used to improve chitosan wound dressing sponge-based local antibiotic delivery systems. In vitro assays in this study demonstrate that vancomycin and amikacin have a synergistic relationship against a strain of osteomyelitis-producing Gram-positive Staphylococcus aureus, although an indifferent relationship was observed against Gram-negative Pseudomonas aeruginosa. In an in vivo model of orthopedic hardware-associated polymicrobial (S. aureus and Escherichia coli) biofilm, chitosan sponges loaded with a combination of vancomycin and amikacin at 5 mg/mL each showed a greater percentage of complete clearance, 50%, than either antibiotic alone, 8.33%. Doubling the loading concentration of the combination achieved a complete clearance rate of 100%, a four log-fold reduction of S. aureus on the wire and a six log-fold reduction in bone. E. coli was detected in bone of untreated animals but did not form biofilm on wires. Results demonstrate the clinical potential of chitosan sponges to prevent infection and illustrates antibiotic selection and loading concentrations necessary for effective biofilm prevention.}, } @article {pmid29635279, year = {2018}, author = {Hashemi, MM and Rovig, J and Holden, BS and Taylor, MF and Weber, S and Wilson, J and Hilton, B and Zaugg, AL and Ellis, SW and Yost, CD and Finnegan, PM and Kistler, CK and Berkow, EL and Deng, S and Lockhart, SR and Peterson, M and Savage, PB}, title = {Ceragenins are active against drug-resistant Candida auris clinical isolates in planktonic and biofilm forms.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {6}, pages = {1537-1545}, doi = {10.1093/jac/dky085}, pmid = {29635279}, issn = {1460-2091}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Candidiasis/drug therapy/microbiology ; Cell Culture Techniques ; Drug Discovery ; *Drug Resistance, Fungal ; Female ; Gels/pharmacology ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Skin Cream/pharmacology ; Steroids/chemistry/*pharmacology ; Swine ; Vagina/cytology/drug effects/microbiology ; }, abstract = {BACKGROUND: Candida auris has emerged as a serious threat to human health. Of particular concern are the resistance profiles of many clinical isolates, with some being resistant to multiple classes of antifungals.

OBJECTIVES: Measure susceptibilities of C. auris isolates, in planktonic and biofilm forms, to ceragenins (CSAs). Determine the effectiveness of selected ceragenins in gel and cream formulations in eradicating fungal infections in tissue explants.

MATERIALS AND METHODS: A collection of 100 C. auris isolates available at CDC was screened for susceptibility to a lead ceragenin. A smaller collection was used to characterize antifungal activities of other ceragenins against organisms in planktonic and biofilm forms. Effects of ceragenins on fungal cells and biofilms were observed via microscopy. An ex vivo model of mucosal fungal infection was used to evaluate formulated forms of lead ceragenins.

RESULTS: Lead ceragenins displayed activities comparable to those of known antifungal agents against C. auris isolates with MICs of 0.5-8 mg/L and minimum fungicidal concentrations (MFCs) of 2-64 mg/L. No cross-resistance with other antifungals was observed. Fungal cell morphology was altered in response to ceragenin treatment. Ceragenins exhibited activity against sessile organisms in biofilms. Gel and cream formulations including 2% CSA-44 or CSA-131 resulted in reductions of over 4 logs against established fungal infections in ex vivo mucosal tissues.

CONCLUSIONS: Ceragenins demonstrated activity against C. auris, suggesting that these compounds warrant further study to determine whether they can be used for topical applications to skin and mucosal tissues for treatment of infections with C. auris and other fungi.}, } @article {pmid29635151, year = {2018}, author = {Zhang, Q and Yu, Z and Zhu, L and Ye, T and Zuo, J and Li, X and Xiao, B and Jin, S}, title = {Vertical-algal-biofilm enhanced raceway pond for cost-effective wastewater treatment and value-added products production.}, journal = {Water research}, volume = {139}, number = {}, pages = {144-157}, doi = {10.1016/j.watres.2018.03.076}, pmid = {29635151}, issn = {1879-2448}, mesh = {Biofilms ; Biofuels ; Biomass ; Chlorophyta/*metabolism/physiology ; Cost-Benefit Analysis ; Cyanobacteria/*metabolism/physiology ; Lipid Metabolism ; Microalgae/*metabolism/physiology ; Nitrogen/metabolism ; Phosphorus/metabolism ; Ponds ; Waste Disposal, Fluid/economics/*methods ; Wastewater ; Water Pollutants/metabolism ; }, abstract = {A win-win strategy by the integration of wastewater treatment with value-added products production through a vertical-algal-biofilm enhanced raceway was investigated in the present study. Raceway pond was enhanced by vertically setting the biofilm in the system with a certain interval distance that could be adjusted for different light conditions and wastewater types. Two types of synthetic wastewater were treated with suitability-proven materials as biofilm carriers under four operation distances. Composition of the harvested algal biomass was analyzed. Coral velvet with 5-8 mm length villus was the optimal carrier, since it was durable and with high biomass productivity (6.95-8.11 g m[-2]·day[-1]). Nutrients in the wastewaters were efficiently removed with the COD, TN and TP reduction of over 86.61%, 73.68% and 89.85%, respectively. Wastewater with the low nutrients concentration experienced lower biomass and lipid productivity but larger biodiesel productivity and higher nutrient removal efficiency. In addition, as the operation distance increased, wastewater treatment efficiency was first increased but then decreased, while algal biomass footprint production was decreased. Differences in nutrients removal efficiencies were mainly due to the distance difference, which caused different biofilm culture surface areas and light regimes. The optimal operation distance as a function of the efficient nutrient removal and biodiesel production in this study was 6 cm.}, } @article {pmid29632199, year = {2018}, author = {Armbruster, CR and Parsek, MR}, title = {New insight into the early stages of biofilm formation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {17}, pages = {4317-4319}, pmid = {29632199}, issn = {1091-6490}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; T32 GM007270/GM/NIGMS NIH HHS/United States ; T32 HL129949/HL/NHLBI NIH HHS/United States ; }, mesh = {*Biofilms ; }, } @article {pmid29631141, year = {2018}, author = {Cui, X and Huo, M and Chen, C and Yu, Z and Zhou, C and Li, A and Qiao, B and Zhou, D and Crittenden, JC}, title = {Low concentrations of Al(III) accelerate the formation of biofilm: Multiple effects of hormesis and flocculation.}, journal = {The Science of the total environment}, volume = {634}, number = {}, pages = {516-524}, doi = {10.1016/j.scitotenv.2018.03.376}, pmid = {29631141}, issn = {1879-1026}, mesh = {Aluminum/*metabolism ; Biofilms/*growth & development ; Biofouling ; Flocculation ; Hormesis ; Waste Disposal, Fluid/*methods ; *Water Microbiology ; Water Purification ; }, abstract = {Residual Al(III) (at low concentration) is common in water treatment plants (WTPs) and is associated with bacteria. We hypothesize that Al(III) accelerate biofouling due to its hydrolysis and hormesis characteristics, as compared with other cations. To verify this, we elaborated the roles of Al(III) at low concentrations on the biofilm formation. Al(III) hormesis (<2.0mg/L) stimulated bacteria growth increased by ~3.7 times, and extracellular polymeric substances production also enhanced. Al(III) flocculation resulted in the suspended cells precipitation instantly, for Al(III) dosages of 0.6 and 2.0mg/L and the concentration of Al(III) decreased by 0.07 and 0.14mg/L, respectively. Al(III) poisoned the bridged bacterial cells and decreased their ATP by 22.36% and 55.91%, respectively. Al(III) formed polymer presented strong affinity with bacterial outer membrane, and this damaged the bacterial outer membrane. This caused proteins to leak at the combined point. Al-polymer bound to NH2 and/or NH on the leaked protein, contributed to biofilm formation. Biofilm maturity was aided by polysaccharides, which shielded Al(III) toxicity for the formed biofilm. Thus, the biofilm exhibited a distinguished double-layer microstructure, principally with proteins and inactivated cells at the bottom, polysaccharides and activated cells at the top. Thus, hormesis and flocculation caused by low concentration Al(III) mutually promoted each other, and together accelerated biofilm formation.}, } @article {pmid29630806, year = {2018}, author = {Xiang, J and Li, H and Pan, B and Chang, J and He, Y and He, T and Strand, R and Shi, Y and Dong, W}, title = {Penetration and bactericidal efficacy of two oral care products in an oral biofilm model.}, journal = {American journal of dentistry}, volume = {31}, number = {1}, pages = {53-60}, pmid = {29630806}, issn = {0894-8275}, mesh = {Adult ; *Anti-Infective Agents, Local/pharmacology ; *Biofilms ; *Cetylpyridinium/pharmacology ; China ; *Dental Plaque/drug therapy ; Humans ; Mouthwashes ; Young Adult ; }, abstract = {PURPOSE: To investigate the immediate penetration and bactericidal effect of two oral care products marketed in China on an intact natural plaque biofilm model at different time points.

METHODS: Eight subjects (aged 20 to 30 years; Turesky Plaque Index Score 2 to 3) were enrolled in the study according to the inclusion criteria. Plaque accumulators were worn by the subjects for 6 and 48 hours for harvesting the dental biofilm. Then the biofilms from different groups were stained with the LIVE/DEAD BacLight fluorescence system to investigate the changes in thickness and fluorescence intensity of living bacteria in biofilm 5 and 15 minutes post-treatment with a mouthrinse containing 0.074% cetylpyridinium chloride (1-minute treatment) or a toothpaste supernatant containing 1.16% stannous chloride (2-minute treatment). In addition, a specific Sn2+ probe was utilized to evaluate the penetration of Sn2+ in the biofilm. Fluorescent images were collected using confocal laser scanning microscopy. Analysis of covariance was used for statistical analyses. All comparisons were two-sided using a 5% level of significance.

RESULTS: The thickness of generated plaque biofilm increased gradually from 7.352±4.22 µm at 6 hours to 16.73±7.38 µm at 48 hours (P< 0.05), whereas the thickness and fluorescence intensity of living bacteria stayed unchanged over time. After the treatment of toothpaste supernatant, the ratios of living bacteria thickness and fluorescence intensity of 6- and 48-hour plaque biofilm were significantly decreased (P< 0.05). Treatment of mouthrinse reduced the ratio of living bacteria thickness, but showed no significant impact on overall fluorescence intensity of living bacteria. For 48-hour biofilm, toothpaste supernatant significantly reduced fluorescence intensity of living bacteria from outer layer through inner layer, whereas the mouthrinse showed bactericidal effect only in the outer layer and middle layer. A wide distribution of Sn2+ was shown in the biofilm with the treatment of the tested toothpaste.

CLINICAL SIGNIFICANCE: This biofilm model proved to be useful and appropriate for pre-clinical testing of anti-plaque agents. A brief exposure of the biofilm to the tested toothpaste produced significant losses in bacteria viability across outer-middle-inner layers. The tested mouthrinse exerted its bactericidal effect mostly in outer and middle layers of biofilm. The penetration of Sn2+ in the biofilm performed an important function in the bactericidal effect of the toothpaste.}, } @article {pmid29630805, year = {2018}, author = {De Foggi, CC and Ayres, MSB and Feltrin, GP and Jorge, JH and Machado, AL}, title = {Effect of surface characteristics of soft liners and tissue conditioners and saliva on the adhesion and biofilm formation.}, journal = {American journal of dentistry}, volume = {31}, number = {1}, pages = {45-52}, pmid = {29630805}, issn = {0894-8275}, mesh = {Acrylic Resins ; *Biofilms ; *Denture Liners ; Humans ; *Methicillin-Resistant Staphylococcus aureus/isolation & purification ; *Saliva/microbiology ; Surface Properties ; }, abstract = {PURPOSE: To investigate the influence of surface characteristics and saliva on the adhesion and biofilm formation of Candida glabrata and methicillin-resistant Staphylococcus aureus (MRSA) to soft liners and tissue conditioners.

METHODS: For each material (Ufi Gel P - UG; Sofreliner S - SS; Trusoft - TR; Coe Comfort - CC; Softone - ST), specimens were prepared and roughness (Ra), hydrophobicity (water contact angles-WCA) and surface free energy (SFE) were measured. Surface morphology was also analyzed using scanning electron microscopy (SEM). Specimens were incubated in C. glabrata or MRSA suspensions for 90 minutes (adhesion) or 48 hours (biofilm). The absorbance (AB) was measured by XTT assay. Experiments were performed using specimens that were either uncoated or had been coated with saliva. Data were analyzed using one- or two-way ANOVAs, followed by Tukey's test (α= 0.05).

RESULTS: TR exhibited the highest Ra and UG the lowest. SEM images also showed that UG and SS had smooth surfaces, while TR presented several irregularities and pores. In the absence of saliva, UG and SS presented higher WCA and lower SFE than the other materials. XTT results showed that, in the C. glabrata adhesion assay, the AB value was higher for TR followed by UG > CC> SS> ST. For the biofilm formation of C. glabrata, AB values were in the following order TR > CC = UG > ST = SS. In the adhesion assay, AB values obtained for MRSA were TR > UG = CC > ST > SS and for the biofilm formation were TR > ST > CC > UG > SS. Saliva decreased the WCA and increased the SFE for all materials. In general, the presence of saliva decreased the adhesion and biofilm formation of both microorganisms to the acrylic-based material (TR) and tissue conditioners (CC and ST), and increased for the silicone-based soft liners (UH and SS). Surface characteristics and the influence of saliva varied among materials. Roughness seemed to favor C. glabrata and MRSA adhesion and biofilm formation.

CLINICAL SIGNIFICANCE: The presence of microorganisms on denture liners can irritate the oral tissues and contribute to systemic diseases. Colonization with more tolerant microorganisms such as C. glabrata and MRSA may expose patients to a greater risk of infection, mainly in immunocompromised hosts, such as aged individuals after treatment of oral cancer. For this, it is important to investigate the surface characteristics of soft liners and tissue conditioners, as well as saliva, and their influence on the adhesion and biofilm formation of C. glabrata and methicillin-resistant Staphylococcus aureus.}, } @article {pmid29630788, year = {2018}, author = {Horiuchi, S and Yumoto, H and Kimura, T and Sato, M and Mitsui, SN and Hiasa, M and Nishikawa, E and El-Bialy, T and Tanaka, E}, title = {Effect of pulsed ultrasound toothbrush on Streptococcus mutans biofilm removal.}, journal = {American journal of dentistry}, volume = {31}, number = {2}, pages = {67-70}, pmid = {29630788}, issn = {0894-8275}, mesh = {Biofilms ; *Dental Plaque ; Humans ; *Streptococcus mutans ; *Toothbrushing/instrumentation ; *Ultrasonic Waves ; }, abstract = {PURPOSE: To evaluate the effect of pulsed ultrasound toothbrush on the removal of biofilm formed by Streptococcus mutans (S. mutans).

METHODS: S. mutans biofilm grown on apatite pellet was destructed with four different sonic action toothbrushes: 1) pulsed ultrasound with sonic vibration (PUV); 2) continuous ultrasound with sonic vibration (CUV); 3) sonic vibration only (SV); and 4) no ultrasound nor sonic vibration (control). After 3 minutes of noncontact brushing, the amount of water-insoluble glucan was measured, and the residual biofilm was observed by scanning electron microscopy.

RESULTS: PUV group revealed the smallest amount of the residual water-insoluble glucans (32 ± 19%), followed by the CUV group (54 ± 12%) and the SV group (64 ± 13%). The PUV group showed a significantly lower amount of the residual water-insoluble glucan than the SV group, while no significant difference was found between SV and CUV. The bacterial adherence and aggregation notably decreased in the PUV group, compared to the remaining three groups.

CLINICAL SIGNIFICANCE: The sonic vibration with pulsed ultrasound showed more reduction of the biofilm compared to the control and the sonic vibration with and without continuous ultrasound. Thus, pulsed ultrasound action may be beneficial for biofilm removal of interproximal regions.}, } @article {pmid29628998, year = {2018}, author = {Matsumoto-Nakano, M}, title = {Role of Streptococcus mutans surface proteins for biofilm formation.}, journal = {The Japanese dental science review}, volume = {54}, number = {1}, pages = {22-29}, pmid = {29628998}, issn = {1882-7616}, abstract = {Streptococcus mutans has been implicated as a primary causative agent of dental caries in humans. An important virulence property of the bacterium is its ability to form biofilm known as dental plaque on tooth surfaces. In addition, this organism also produces glucosyltransferases, multiple glucan-binding proteins, protein antigen c, and collagen-binding protein, surface proteins that coordinate to produce dental plaque, thus inducing dental caries. Bacteria utilize quorum-sensing systems to modulate environmental stress responses. A major mechanism of response to signals is represented by the so called two-component signal transduction system, which enables bacteria to regulate their gene expression and coordinate activities in response to environmental stress. As for S. mutans, a signal peptide-mediated quorum-sensing system encoded by comCDE has been found to be a regulatory system that responds to cell density and certain environmental stresses by excreting a peptide signal molecule termed CSP (competence-stimulating peptide). One of its principal virulence factors is production of bacteriocins (peptide antibiotics) referred to as mutacins. Two-component signal transduction systems are commonly utilized by bacteria to regulate bacteriocin gene expression and are also related to biofilm formation by S. mutans.}, } @article {pmid29627868, year = {2018}, author = {Chen, H and Li, A and Wang, Q and Cui, D and Cui, C and Ma, F}, title = {Nitrogen removal performance and microbial community of an enhanced multistage A/O biofilm reactor treating low-strength domestic wastewater.}, journal = {Biodegradation}, volume = {29}, number = {3}, pages = {285-299}, doi = {10.1007/s10532-018-9829-x}, pmid = {29627868}, issn = {1572-9729}, support = {51608154//National Natural Science Foundation of China/International ; 51478140//National Natural Science Foundation of China/International ; HC201526-01//Open Project of State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology/International ; Guikehe1599005-2-2//the Science Research and Technology Development Project of Guangxi/International ; HSCJ201604//the HIT Environment and Ecology Innovation Special Funds/International ; }, mesh = {Bacteria/*metabolism ; Biodegradation, Environmental ; Biodiversity ; *Biofilms ; Bioreactors/*microbiology ; Nitrogen/analysis/*isolation & purification ; Time Factors ; Waste Disposal, Fluid ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {The low-strength domestic wastewater (LSDW) treatment with low chemical oxygen demand (COD) has drawn extensive attention for the poor total nitrogen (TN) removal performance. In the present study, an enhanced multistage anoxic/oxic (A/O) biofilm reactor was designed to improve the TN removal performance of the LSDW treatment. Efficient nitrifying and denitrifying biofilm carriers were cultivated and then filled into the enhanced biofilm reactor as the sole microbial source. Step-feed strategy and internal recycle were adopted to optimize the substrate distribution and the organics utilization. Key operational parameters were optimized to obtain the best nitrogen and organics removal efficiencies. A hydraulic retention time of 8 h, an influent distribution ratio of 2:1 and an internal recycle ratio of 200% were tested as the optimum parameters. The ammonium, TN and COD removal efficiencies under the optimal operational parameters separately achieved 99.75 ± 0.21, 59.51 ± 1.95 and 85.06 ± 0.79% with an organic loading rate at around 0.36 kg COD/m[3] d. The high-throughput sequencing technology confirmed that nitrifying and denitrifying biofilm could maintain functional bacteria in the system during long-period operation. Proteobacteria and Bacteroidetes were the dominant phyla in all the nitrifying and denitrifying biofilm samples. Nitrosomonadaceae_uncultured and Nitrospira sp. stably existed in nitrifying biofilm as the main nitrifiers, while several heterotrophic genera, such as Thauera sp. and Flavobacterium sp., acted as potential genera responsible for TN removal in denitrifying biofilm. These findings suggested that the enhanced biofilm reactor could be a promising route for the treatment of LSDW with a low COD level.}, } @article {pmid29627603, year = {2018}, author = {Zhang, J and Li, W and Chen, J and Qi, W and Wang, F and Zhou, Y}, title = {Impact of biofilm formation and detachment on the transmission of bacterial antibiotic resistance in drinking water distribution systems.}, journal = {Chemosphere}, volume = {203}, number = {}, pages = {368-380}, doi = {10.1016/j.chemosphere.2018.03.143}, pmid = {29627603}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects ; Biofilms/drug effects/*growth & development ; Disinfectants/pharmacology ; Drinking Water/*microbiology ; Drug Resistance, Bacterial/drug effects/*genetics ; Water Purification ; }, abstract = {There is growing awareness of the antibiotic-resistance crisis and its implications for public health among clinicians, researchers, politicians, and the public. We studied bacterial antibiotic resistance transition and the role of biofilms in a drinking water distribution system (DWDS). We tracked several different antibiotic resistant bacteria (ARB) with resistance to tetracycline, sulfamethoxazole, clindamycin, and norfloxacin for one year in a DWDS. The results indicated that the amount of ARB increased in tap water, presumably due to biofilm detachment. The effect of biofilm detachment on the transmission of antibiotic resistance from biofilms to tap water was explored by using a bacterial annular reactor. The percentage of ARB of inlet water, outlet water, and biofilms ranged from 0.26% to 9.85%, 1.08%-16.29%, and 0.52%-29.97%, respectively in a chlorinated system, and from 0.23% to 9.89%, 0.84%-16.84%, and 0.35%-17.77%, respectively, in a chloraminated system. The relative abundances of antibiotic resistance Acinetobacter, Sphingomonas, and Bradyrhizobium were higher in outlet water than in inlet water, as determined by high throughout sequencing. The amount of ARB percentage varied with the concentration of viable but non-culturable (VBNC) cells (r = 0.21, n = 160, P < 0.05) in biofilm, suggesting a higher antibiotic resistance mutation rate in VBNC cells. Our results suggest that biofilm detachment was promoted by disinfectant and affected the overall bacterial antibiotic resistance of microbes in tap water.}, } @article {pmid29627449, year = {2018}, author = {Peng, LY and Yuan, M and Cui, ZQ and Wu, ZM and Yu, ZJ and Song, K and Tang, B and Fu, BD}, title = {Rutin inhibits quorum sensing, biofilm formation and virulence genes in avian pathogenic Escherichia coli.}, journal = {Microbial pathogenesis}, volume = {119}, number = {}, pages = {54-59}, doi = {10.1016/j.micpath.2018.04.007}, pmid = {29627449}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/drug effects ; Alveolar Epithelial Cells/microbiology ; Animals ; Biofilms/*drug effects/growth & development ; Carrier Proteins/drug effects/genetics ; Cell Survival/drug effects ; Chickens ; Escherichia coli/*drug effects/*genetics/growth & development/pathogenicity ; Escherichia coli Infections/drug therapy/microbiology/*veterinary ; Escherichia coli Proteins/drug effects/genetics ; Gene Expression Regulation, Bacterial/*drug effects/genetics ; L-Lactate Dehydrogenase/analysis ; Microbial Sensitivity Tests ; Poultry Diseases/drug therapy/microbiology ; Quorum Sensing/*drug effects ; Rutin/*antagonists & inhibitors/chemistry ; Virulence/drug effects/genetics ; Virulence Factors/*genetics ; }, abstract = {The study aimed to investigate whether rutin affects the quorum sensing (QS) of avian pathogenic Escherichia coli (APEC). In this study, APEC-O78 was selected as the test strain. We mainly examined the effects of rutin on the AI-2 secretion by bioluminescence assay, biofilm formation through a crystal violet staining method, and expression of virulence genes of APEC by qRT-PCR. We found that rutin can significantly interfering with QS through reducing the secretion of AI-2, inhibited the biofilm formation, and reduced the expression of virulence genes of APEC. Moreover, rutin markedly decreased adhesion and damage of APEC to chicken type II pneumocytes. These results suggested rutin reduces cell damage of APEC-infected chicken type II pneumocytes through interfering with QS via decreasing AI-2 production, biofilm formation, and the expression of virulence genes. This paper may provide a new evidence for colibacillosis prevention in chicken.}, } @article {pmid29627417, year = {2018}, author = {Tarafdar, A and Sarkar, TK and Chakraborty, S and Sinha, A and Masto, RE}, title = {Biofilm development of Bacillus thuringiensis on MWCNT buckypaper: Adsorption-synergic biodegradation of phenanthrene.}, journal = {Ecotoxicology and environmental safety}, volume = {157}, number = {}, pages = {327-334}, doi = {10.1016/j.ecoenv.2018.03.090}, pmid = {29627417}, issn = {1090-2414}, mesh = {Adsorption ; Bacillus thuringiensis/*metabolism ; Biodegradation, Environmental ; Biofilms/*growth & development ; Nanotubes, Carbon/chemistry/*microbiology ; Phenanthrenes/*analysis ; Surface Properties ; Water Pollutants, Chemical/*analysis ; }, abstract = {Adsorption-synergic biodegradation of a model PAH (phenanthrene, Phe) on MWCNT buckypaper surface with a potential PAH biodegrading bacterial strain Bacillus thuringiensis AT.ISM.11 has been studied in aqueous medium. Adsorption of Phe on buckypaper follows Dubinin-Ashtakhov model (R[2] = 0.9895). MWCNT generally exerts toxicity to microbes but adsorbed layer of Phe prevents the direct contact between MWCNT and bacterial cell wall. FESEM study suggests that formation of biofilms occurred on buckypaper. Lower layer cells are disrupted and flattened as they are in direct contact with MWCNT but the upper layer cells of the developed biofilm are fully intact and functional. Force-distance curves of Bacillus thuringiensis AT.ISM.11 with buckypaper indicates adhesion forces varied from -10.3 to -15.6 nN with increasing contact time, which supports the phenomenon of biofilm formation. AFM surface statistical data of buckypaper suggests increase in bacterial cell count increases the Rms roughness (95.7242-632.565) while adhering to the buckypaper surface to form biofilm. We observed an enhanced Phe biodegradation of 93.81% from that of the 65.71% in 15 days' study period, using buckypaper as a bio-carrier or a matrix for the microbial growth. GC-MS study identified phthalic acid ester as metabolite, which is the evidence of protocatechuate pathway degradation of Phe. Current study enlightens the interaction between hydrocarbons and microbes in presence of MWCNT buckypaper matrix in aqueous system for the first time. An enhancement in biodegradation of Phe by 28.10% has also been reported which can be a basis for CNT aided enhanced biodegradation studies in future.}, } @article {pmid29626780, year = {2018}, author = {Arij, Y and Fatihah, S and Rakmi, AR}, title = {Performance of pilot scale anaerobic biofilm digester (ABD) for the treatment of leachate from a municipal waste transfer station.}, journal = {Bioresource technology}, volume = {260}, number = {}, pages = {213-220}, doi = {10.1016/j.biortech.2018.03.131}, pmid = {29626780}, issn = {1873-2976}, mesh = {Ammonia ; Anaerobiosis ; *Biofilms ; Bioreactors ; Malaysia ; Methane ; *Phosphorus ; }, abstract = {The anaerobic treatment of leachate from a municipal waste transfer station in Malaysia was tested using a pilot scale anaerobic biofilm digester system that was operated under HRT sequence of 30-day, 25-day, 20-day and 10-day for 163 days under mesophilic conditions. Despite the leachate's complex characteristics, the system showed great performance given its maximum COD, BOD5 and total phosphorus removal efficiencies of 98 ± 1%, 99 ± 1% and 92 ± 9% respectively. The system was stable throughout its operation and showed optimal average values for the monitored parameters such as pH (7.53 ± 0.14), total VFA (79 ± 66 mg HOAc/L), alkalinity (10,919 ± 1556 mg CaCO3/L) and a non-toxic value for accumulated ammonia (960 ± 106 mg NH3-N/L). Measurement of the average daily biogas production yielded a value of 25 ± 1 m[3]/day throughout the system's operation with a composition of 57 ± 12% methane and 26 ± 6% carbon dioxide.}, } @article {pmid29626763, year = {2018}, author = {Ma, W and Panecka, M and Tufenkji, N and Rahaman, MS}, title = {Bacteriophage-based strategies for biofouling control in ultrafiltration: In situ biofouling mitigation, biocidal additives and biofilm cleanser.}, journal = {Journal of colloid and interface science}, volume = {523}, number = {}, pages = {254-265}, doi = {10.1016/j.jcis.2018.03.105}, pmid = {29626763}, issn = {1095-7103}, mesh = {Bacteriophage T4/*physiology ; *Biofilms ; Biofouling/*prevention & control ; Escherichia coli/*growth & development/virology ; Membranes, Artificial ; Oxygen/chemistry ; Surface Properties ; Ultrafiltration/instrumentation/*methods ; Water Purification/methods ; }, abstract = {The ability of bacteriophages to infect and destroy specific bacteria makes them promising antimicrobial agents in industrial processes. In this study, potential strategies of bacteriophage-facilitated biofouling control during membrane ultrafiltration (UF) were investigated through use of the model T4 bacteriophage and the model host bacterium, Escherichia coli. In the dead-end filtration mode, phages were immobilized on the membrane surface to serve as biocidal agents and inhibit the propagation of bacteria in situ. After 6 h of filtration, a 36% flux reduction was observed for the T4-functionalized membrane in comparison to 71% for the non-functionalized membrane. Surface modification of the membrane using O2 plasma treatment resulted in increased numbers of bound phage and enhanced biofouling resistance of the membrane. Introducing the phage into the feed of a cross-flow filtration system effectively mitigated the water flux reduction of the membrane caused by bacterial growth. By modifying the concentration of phage additives, the growth of bacteria was delayed, inhibited, or eliminated. Phage treatment changed the structure of biofilms on the membrane surface and facilitated in situ biofilm cleaning. A 20% greater recovery in water flux was observed for the biofilm-contaminated membrane following phage-assisted cleaning when compared to the membrane cleaned via a physical washing process. Taken together, these results show that bacteriophage assisted anti-biofouling strategies have the potential to mitigate biofouling in membrane processes in an environmentally friendly manner.}, } @article {pmid29626660, year = {2018}, author = {Memariani, H and Memariani, M and Pourmand, MR}, title = {Venom-derived peptide Mastoparan-1 eradicates planktonic and biofilm-embedded methicillin-resistant Staphylococcus aureus isolates.}, journal = {Microbial pathogenesis}, volume = {119}, number = {}, pages = {72-80}, doi = {10.1016/j.micpath.2018.04.008}, pmid = {29626660}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Line/drug effects ; Cell Survival/drug effects ; Erythrocytes/drug effects ; Hemolysis ; Humans ; Intercellular Signaling Peptides and Proteins ; Kinetics ; Methicillin-Resistant Staphylococcus aureus/cytology/*drug effects/isolation & purification ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Peptides/chemistry/*pharmacology ; Protein Conformation ; Time Factors ; Vancomycin/pharmacology ; Wasp Venoms/chemistry/*pharmacology ; Wasps/chemistry ; }, abstract = {During the past decade, cationic antimicrobial peptides (CAPs) have gained particular interest among researchers, since they often display broad-spectrum antimicrobial activity and low possibility of resistance emergence. This study aimed to investigate in vitro effectiveness of Mastoparan-1 (MP-1), a tetradecapeptide CAP from hornet venom, against methicillin-resistant Staphylococcus aureus (MRSA) isolates. MP-1 had a high propensity to form alpha-helix based on structural predictions. MP-1 was found to possess strong antimicrobial activities and weak cytotoxic effects. Multiple treatments of MRSA with MP-1 at sub-lethal dose did not induce resistance. At 4 × minimum bactericidal concentration (MBC), MP-1 eradicated bacteria within 60 min, whereas vancomycin was unable to eradicate MRSA even after 480 min of exposure, highlighting rapid bactericidal kinetics of MP-1. Treatment of bacteria with 2 × MBC of MP-1 caused a time-dependent increase in orange/red fluorescence intensity. Compared with vancomycin, MP-1 significantly reduced biofilm formation and diminished both biofilm biomass and viability of biofilm-embedded bacteria in a concentration-dependent manner. Taken together, the current data reveal not only that MP-1 is a potent bactericidal and antibiofilm agent, but also that it is less likely to invoke antimicrobial resistance, reinforcing further studies concerning the therapeutic applications of MP-1.}, } @article {pmid29624494, year = {2018}, author = {Perfileva, AI and Pavlova, AG and Bukhyanova, BB and Tsivileva, OM}, title = {Pesticides impact on Clavibacter michiganensis ssp. sepedonicus biofilm formation.}, journal = {Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes}, volume = {53}, number = {7}, pages = {464-468}, doi = {10.1080/03601234.2018.1455356}, pmid = {29624494}, issn = {1532-4109}, mesh = {Actinobacteria/*drug effects/pathogenicity/physiology ; Biofilms/drug effects ; Iodoacetic Acid/pharmacology ; Pesticides/*pharmacology ; Solanum tuberosum/microbiology ; }, abstract = {The effect of various pesticides on the biofilm formation by the phytopathogenic bacterium Clavibacter michiganensis ssp. sepedonicus (Cms), the potato ring rot causative agent, was explored for the first time. Systemic herbicides: 2,4-D, diuron, glyphosate, clopyralid, fluorodifen, as well as the commercial preparations "Lazurite," "Ridomil Gold," and the mitochondria inhibiting pesticides analog, sodium monoiodoacetate, were studied. These pesticides' effect on the Cms biofilm formation was shown to be distinct and dependent on the agent under question. Cms biofilm formation was reduced when exposed to sodium monoiodoacetate, as well as "Lazurite" preparation, that could be due to the bactericidal effect of these agents. 2,4-D and "Ridomil Gold" preparation stimulated the biofilm formation. Systemic herbicides diuron, glyphosate, clopyralid, fluorodifen did not exert appreciable influence on the process of bacterial biofilm formation.}, } @article {pmid29623836, year = {2018}, author = {Das, R and Mehta, DK}, title = {Microbial Biofilm and Quorum Sensing Inhibition: Endowment of Medicinal Plants to Combat Multidrug-Resistant Bacteria.}, journal = {Current drug targets}, volume = {19}, number = {16}, pages = {1916-1932}, doi = {10.2174/1389450119666180406111143}, pmid = {29623836}, issn = {1873-5592}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Disease Models, Animal ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Plant Extracts/*pharmacology/therapeutic use ; Plants, Medicinal/*chemistry ; Quorum Sensing/drug effects ; }, abstract = {Continued emergence and spread of multidrug-resistant bacteria behooved the development of alternative treatment strategies, including antimicrobial drugs. A hopeful approach is to target cellto- cell communications, commonly known as quorum-sensing (QS) and microbial biofilm formation. Quorum Sensing is a method used on bacteria to determine their physiological behavior and coordinate gene expression based on the cell to cell signaling. Many physiological functions of bacteria are controlled by quorum sensings such as virulence, motility, sporulation, luminescence, and biofilm formation. Microbial biofilms are organized aggregations of cells attached to a substratum and surrounded by a self-produced extrapolymeric substance (EPS) matrix. Currently, biofilm formation and quorum sensing are considered as a prospective novel target for antimicrobial therapy to control multidrug- resistant infections. Plant-based natural products have been comprehensively studied in this context. In this review, a comprehensive overview of various research papers published in the last decade on plant-derived molecules that are capable of inhibiting quorum sensing or microbial biofilm formation is reviewed, mentioning the biosynthetic classes of active compounds and their biological activity in the performed assays.}, } @article {pmid29621702, year = {2018}, author = {Vyrides, I and Drakou, EM and Ioannou, S and Michael, F and Gatidou, G and Stasinakis, AS}, title = {Biodegradation of bilge water: Batch test under anaerobic and aerobic conditions and performance of three pilot aerobic Moving Bed Biofilm Reactors (MBBRs) at different filling fractions.}, journal = {Journal of environmental management}, volume = {217}, number = {}, pages = {356-362}, doi = {10.1016/j.jenvman.2018.03.086}, pmid = {29621702}, issn = {1095-8630}, mesh = {*Biofilms ; Bioreactors ; Pilot Projects ; *Waste Disposal, Fluid ; Water ; }, abstract = {The bilge water that is stored at the bottom of the ships is saline and greasy wastewater with a high Chemical Oxygen Demand (COD) fluctuations (2-12 g COD L[-1]). The aim of this study was to examine at a laboratory scale the biodegradation of bilge water using first anaerobic granular sludge followed by aerobic microbial consortium (consisted of 5 strains) and vice versa and then based on this to implement a pilot scale study. Batch results showed that granular sludge and aerobic consortium can remove up to 28% of COD in 13 days and 65% of COD removal in 4 days, respectively. The post treatment of anaerobic and aerobic effluent with aerobic consortium and granular sludge resulted in further 35% and 5% COD removal, respectively. The addition of glycine betaine or nitrates to the aerobic consortium did not enhance significantly its ability to remove COD from bilge water. The aerobic microbial consortium was inoculated in 3 pilot (200 L) Moving Bed Biofilm Reactors (MBBRs) under filling fractions of 10%, 20% and 40% and treated real bilge water for 165 days under 36 h HRT. The MBBR with a filling fraction of 40% resulted in the highest COD decrease (60%) compared to the operation of the MBBRs with a filling fraction of 10% and 20%. GC-MS analysis on 165 day pointed out the main organic compounds presence in the influent and in the MBBR (10% filling fraction) effluent.}, } @article {pmid29621296, year = {2018}, author = {Budeli, P and Moropeng, RC and Mpenyana-Monyatsi, L and Momba, MNB}, title = {Inhibition of biofilm formation on the surface of water storage containers using biosand zeolite silver-impregnated clay granular and silver impregnated porous pot filtration systems.}, journal = {PloS one}, volume = {13}, number = {4}, pages = {e0194715}, pmid = {29621296}, issn = {1932-6203}, mesh = {*Aluminum Silicates ; Bacteria/classification/genetics/isolation & purification ; Biofilms/*drug effects ; Clay ; *Filtration/methods ; Porosity ; Silver/*pharmacology ; Water/analysis/chemistry ; Water Microbiology ; *Water Purification/instrumentation/methods ; *Water Supply ; Zeolites/*pharmacology ; }, abstract = {Development of biofilms occurring on the inner surface of storage vessels offers a suitable medium for the growth of microorganisms and consequently contributes to the deterioration of treated drinking water quality in homes. The aim of this study was to determine whether the two point-of-use technologies (biosand zeolite silver-impregnated clay granular (BSZ-SICG) filter and silver-impregnated porous pot (SIPP) filter) deployed in a rural community of South Africa could inhibit the formation of biofilm on the surface of plastic-based containers generally used by rural households for the storage of their drinking water. Culture-based methods and molecular techniques were used to detect the indicator bacteria (Total coliforms, faecal coliform, E. coli) and pathogenic bacteria (Salmonella spp., Shigella spp. and Vibrio cholerae) in intake water and on the surface of storage vessels containing treated water. Scanning electron microscopy was also used to visualize the development of biofilm. Results revealed that the surface water source used by the Makwane community was heavily contaminated and harboured unacceptably high counts of bacteria (heterotrophic plate count: 4.4-4.3 Log10 CFU/100mL, total coliforms: 2.2 Log10 CFU/100 mL-2.1 Log10 CFU/100 mL, faecal coliforms: 1.9 Log10 CFU/100 mL-1.8 Log10 CFU/100 mL, E. coli: 1.7 Log10 CFU/100 mL-1.6 Log10 CFU/100 mL, Salmonella spp.: 3 Log10 CFU/100 mL -8 CFU/100 mL; Shigella spp. and Vibrio cholerae had 1.0 Log10 CFU/100 mL and 0.8 Log10 CFU/100 mL respectively). Biofilm formation was apparent on the surface of the storage containers with untreated water within 24 h. The silver nanoparticles embedded in the clay of the filtration systems provided an effective barrier for the inhibition of biofilm formation on the surface of household water storage containers. Biofilm formation occurred on the surface of storage plastic vessels containing drinking water treated with the SIPP filter between 14 and 21 days, and on those containing drinking water treated with the BSZ-SICG filter between 3 and 14 days. The attachment of target bacteria on the surface of the coupons inoculated in storage containers ranged from (0.07 CFU/cm2-227.8 CFU/cm2). To effectively prevent the development of biofilms on the surface of container-stored water, which can lead to the recontamination of treated water, plastic storage containers should be washed within 14 days for water treated with the SIPP filter and within 3 days for water treated with the BSZ-SICG filter.}, } @article {pmid29619013, year = {2018}, author = {García García, T and Ventroux, M and Derouiche, A and Bidnenko, V and Correia Santos, S and Henry, C and Mijakovic, I and Noirot-Gros, MF and Poncet, S}, title = {Phosphorylation of the Bacillus subtilis Replication Controller YabA Plays a Role in Regulation of Sporulation and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {486}, pmid = {29619013}, issn = {1664-302X}, abstract = {Bacillus subtilis cells can adopt different life-styles in response to various environmental cues, including planktonic cells during vegetative growth, sessile cells during biofilm formation and sporulation. While switching life-styles, bacteria must coordinate the progression of their cell cycle with their physiological status. Our current understanding of the regulatory pathways controlling the decision-making processes and triggering developmental switches highlights a key role of protein phosphorylation. The regulatory mechanisms that integrate the bacterial chromosome replication status with sporulation involve checkpoint proteins that target the replication initiator DnaA or the kinase phosphorelay controlling the master regulator Spo0A. B. subtilis YabA is known to interact with DnaA to prevent over-initiation of replication during vegetative growth. Here, we report that YabA is phosphorylated by YabT, a Ser/Thr kinase expressed during sporulation and biofilm formation. The phosphorylation of YabA has no effect on replication initiation control but hyper-phosphorylation of YabA leads to an increase in sporulation efficiency and a strong inhibition of biofilm formation. We also provide evidence that YabA phosphorylation affects the level of Spo0A-P in cells. These results indicate that YabA is a multifunctional protein with a dual role in regulating replication initiation and life-style switching, thereby providing a potential mechanism for cross-talk and coordination of cellular processes during adaptation to environmental change.}, } @article {pmid29617701, year = {2018}, author = {Yazdi, M and Bouzari, M and Ghaemi, EA}, title = {Isolation and Characterization of a Lytic Bacteriophage (vB_PmiS-TH) and Its Application in Combination with Ampicillin against Planktonic and Biofilm Forms of Proteus mirabilis Isolated from Urinary Tract Infection.}, journal = {Journal of molecular microbiology and biotechnology}, volume = {28}, number = {1}, pages = {37-46}, doi = {10.1159/000487137}, pmid = {29617701}, issn = {1660-2412}, mesh = {Ampicillin/*therapeutic use ; Anti-Bacterial Agents/pharmacology ; Bacteriophages/*classification/*isolation & purification/physiology/ultrastructure ; Biofilms/*drug effects/growth & development ; Humans ; Hydrogen-Ion Concentration ; Phage Therapy/*methods ; Proteus mirabilis/*drug effects/genetics/isolation & purification/*virology ; RNA, Ribosomal, 16S/genetics ; Temperature ; Urinary Tract Infections/*microbiology ; Wastewater/virology ; }, abstract = {Proteus mirabilis is one of the most common causes of urinary tract infection (UTI), particularly in patients undergoing long-term catheterization. Phage vB_PmiS-TH was isolated from wastewater with high lytic activity against P. mirabilis (TH) isolated from UTI. The phage had rapid adsorption, a large burst size (∼260 PFU per infected cell), and high stability at a wide range of temperatures and pH values. As analyzed by transmission electron microscopy, phage vB_PmiS-TH had an icosahedral head of ∼87 × 62 nm with a noncontractile tail about 137 nm in length and 11 nm in width. It belongs to the family Siphoviridae. Combination of the phage vB_PmiS-TH with ampicillin had a higher removal activity against planktonic cells of P. mirabilis (TH) than the phage or the antibiotic alone. Combination of the phage at a multiplicity of infection of 100 with a high dose of ampicillin (246 µg/mL) showed the highest biofilm removal activity after 24 h. This study demonstrates that using a combination of phage and antibiotic could be significantly more effective against planktonic and biofilm forms of P. mirabilis (TH).}, } @article {pmid29617682, year = {2018}, author = {Cieplik, F and Wimmer, F and Muehler, D and Thurnheer, T and Belibasakis, GN and Hiller, KA and Maisch, T and Buchalla, W}, title = {Phenalen-1-One-Mediated Antimicrobial Photodynamic Therapy and Chlorhexidine Applied to a Novel Caries Biofilm Model.}, journal = {Caries research}, volume = {52}, number = {6}, pages = {447-453}, doi = {10.1159/000487815}, pmid = {29617682}, issn = {1421-976X}, mesh = {Actinomyces/drug effects ; Anti-Infective Agents/*therapeutic use ; Biofilms/*drug effects/growth & development ; Chlorhexidine/*therapeutic use ; Dental Caries/*drug therapy ; Humans ; Phenalenes/*therapeutic use ; Photochemotherapy/*methods ; Photosensitizing Agents/*therapeutic use ; Streptococcus mutans/drug effects ; }, abstract = {Antimicrobial photodynamic therapy (aPDT) may be useful as a supportive antimicrobial measure for caries-active subjects. In this study, the antimicrobial efficacy of aPDT with a phenalen-1-one photosensitizer was evaluated in a novel in vitro biofilm model comprising Actinomyces naeslundii, Actinomyces odontolyticus, and Streptococcus mutans and was compared to chlorhexidine. The proposed biofilm model allows high-throughput screening for antimicrobial efficacy while exhibiting a differentiated response to different antimicrobial approaches. While chlorhexidine 0.2% showed a reduction of ≈4 log10 for all species, aPDT led to a more pronounced reduction of S. mutans (2.8 log10) than of Actinomyces spp. (1.2 or 1.3 log10). A similar effect was also observed in monospecies biofilms. Therefore, aPDT may be more effective against S. mutans than against Actinomyces spp. when in biofilms, and this antimicrobial approach merits further investigations.}, } @article {pmid29615504, year = {2018}, author = {Dominguez, E and Zarnowski, R and Sanchez, H and Covelli, AS and Westler, WM and Azadi, P and Nett, J and Mitchell, AP and Andes, DR}, title = {Conservation and Divergence in the Candida Species Biofilm Matrix Mannan-Glucan Complex Structure, Function, and Genetic Control.}, journal = {mBio}, volume = {9}, number = {2}, pages = {}, pmid = {29615504}, issn = {2150-7511}, support = {P41 RR002301/RR/NCRR NIH HHS/United States ; S10 RR029220/RR/NCRR NIH HHS/United States ; P41 GM103399/GM/NIGMS NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; S10 RR023438/RR/NCRR NIH HHS/United States ; S10 RR025062/RR/NCRR NIH HHS/United States ; }, mesh = {Antifungal Agents/metabolism/pharmacology ; Candida/chemistry/drug effects/genetics/*metabolism ; Drug Resistance, Fungal ; Enzymes/metabolism ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism ; Glucans/chemistry/*metabolism ; Mannans/chemistry/*metabolism ; Metabolic Networks and Pathways ; }, abstract = {Candida biofilms resist the effects of available antifungal therapies. Prior studies with Candida albicans biofilms show that an extracellular matrix mannan-glucan complex (MGCx) contributes to antifungal sequestration, leading to drug resistance. Here we implement biochemical, pharmacological, and genetic approaches to explore a similar mechanism of resistance for the three most common clinically encountered non-albicansCandida species (NAC). Our findings reveal that each Candida species biofilm synthesizes a mannan-glucan complex and that the antifungal-protective function of this complex is conserved. Structural similarities extended primarily to the polysaccharide backbone (α-1,6-mannan and β-1,6-glucan). Surprisingly, biochemical analysis uncovered stark differences in the branching side chains of the MGCx among the species. Consistent with the structural analysis, similarities in the genetic control of MGCx production for each Candida species also appeared limited to the synthesis of the polysaccharide backbone. Each species appears to employ a unique subset of modification enzymes for MGCx synthesis, likely accounting for the observed side chain diversity. Our results argue for the conservation of matrix function among Candida spp. While biogenesis is preserved at the level of the mannan-glucan complex backbone, divergence emerges for construction of branching side chains. Thus, the MGCx backbone represents an ideal drug target for effective pan-Candida species biofilm therapy.IMPORTANCECandida species, the most common fungal pathogens, frequently grow as a biofilm. These adherent communities tolerate extremely high concentrations of antifungal agents, due in large part, to a protective extracellular matrix. The present studies define the structural, functional, and genetic similarities and differences in the biofilm matrix from the four most common Candida species. Each species synthesizes an extracellular mannan-glucan complex (MGCx) which contributes to sequestration of antifungal drug, shielding the fungus from this external assault. Synthesis of a common polysaccharide backbone appears conserved. However, subtle structural differences in the branching side chains likely rely upon unique modification enzymes, which are species specific. Our findings identify MGCx backbone synthesis as a potential pan-Candida biofilm therapeutic target.}, } @article {pmid29614999, year = {2018}, author = {Kim, DJ and Park, JH and Chang, M}, title = {Species-specific characteristics of the biofilm generated in silicone tube: an in vitro study.}, journal = {BMC ophthalmology}, volume = {18}, number = {1}, pages = {85}, pmid = {29614999}, issn = {1471-2415}, support = {S-2014-G0001-00024//Dongguk University/ ; }, mesh = {Analysis of Variance ; Biofilms/*growth & development ; Dacryocystorhinostomy/*instrumentation ; Gram-Positive Bacteria/isolation & purification/*physiology ; Humans ; Nasolacrimal Duct/surgery ; Pseudomonas/*isolation & purification ; Silicones ; Species Specificity ; Stents/*microbiology ; }, abstract = {BACKGROUND: To investigate characteristics of biofilm which is usually found in silicone tube for nasolacrimal duct surgery and can be the root of chronic bacterial infections eventually resulted in surgical failure.

METHODS: To form a biofilm, sterile silicone tube was placed in culture media of Staphylococcus aureus, Corynebacterium matruchotii, Pseudomonas aeruginosa, or Streptococcus pneumonia. Biofilms formed on these silicone tubes were fixed with 95% ethanol and stained with 0.1% crystal violet. After staining, the optical densities of biofilms were measured using spectrophotometer on a weekly basis for 12 weeks.

RESULTS: Staphylococcus aureus group and Pseudomonas aeruginosa group formed significantly more amounts of biofilms compared to the control group. The maximum optical densities of the two groups were found on week 3-4 followed by a tendency of decrease afterwards. However, the amounts of biofilms formed in other groups of silicone tubes were not statistically significant from that of the control group.

CONCLUSIONS: Bacterial species that could form biofilm on silicone tube included Staphylococcus aureus (week 3) and Pseudomonas aeruginosa (Week 4). It is important to first consider that the cause of infection around 1 month after silicone tube intubation can be Staphylococcus aureus and Pseudomonas aeruginosa.}, } @article {pmid29611650, year = {2017}, author = {Vasil', M and Farkasova, Z and Elecko, J and Illek, J and Zigo, F}, title = {Comparison of biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis strains isolated from sheep milk using three diagnostic methods.}, journal = {Polish journal of veterinary sciences}, volume = {20}, number = {4}, pages = {795-801}, doi = {10.1515/pjvs-2017-0100}, pmid = {29611650}, issn = {1505-1773}, mesh = {Animals ; Bacteriological Techniques ; Biofilms/*growth & development ; DNA, Bacterial/isolation & purification ; Milk/*microbiology ; Sensitivity and Specificity ; Sheep/*microbiology ; Staphylococcus aureus/*physiology ; Staphylococcus epidermidis/*physiology ; }, abstract = {In this study we investigated 24 strains of Staphylococcus aureus and 33 strains of Staphylococcus epidermidis isolated from milk of sheep with clinical mastitis, for their ability to form biofilms. Three methods for the determination of a biofilm were used. When evaluating the growth on Congo Red agar (CRA), 79.2% S. aureus strains and 72.7% S. epidermidis strains were positive for biofilm formation. The quantitative method of biofilm detection on a Microtitre Plate (MTP) revealed positive results for 75.0% of S. aureus samples and 75.8% for S. epidermidis samples. Using PCR method for determination of the presence of genes that affect formation of biofilms, the most frequently determined genes were eno in both S. aureus (18/24; 75.0%) and S. epidermidis strains (20/33; 60.6%). The genes icaAB and ebpS were detected in both S. aureus and S. epidermidis strains, and similarity between these strains was 12.5% - 15.1% and 4.2% - 6.0%, respectively. The bap was recorded only in S. epidermidis (3.0%). Statistical comparison of the level of biofilm formation was performed using Chi square test. There were no statistically significant differences in the amount of biofilm formation between two methods for detection of biofilm CRA and MTP (p>0.05). Comparison of all six monitored parameters showed no dependence of characteristics of the tested strains S. aureus and S. epidermidis at significance level α = 0.05. Biofilm formation by the bacteria isolated from 57 cases of clinical mastitis in sheep was confirmed. Sensitivity and specificity of the CRA method for S. aureus were 94.44% and 66.66%, respectively, and for S. epidermidis 92.0% and 87.5%, respectively. Both CRA and MTP methods can be recommended for the detection of biofilm production by S. aureus and S. epidermidis strains isolated from milk of sheep with clinical mastitis.}, } @article {pmid29610314, year = {2018}, author = {Bocci, F and Suzuki, Y and Lu, M and Onuchic, JN}, title = {Role of metabolic spatiotemporal dynamics in regulating biofilm colony expansion.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {16}, pages = {4288-4293}, pmid = {29610314}, issn = {1091-6490}, support = {P30 CA034196/CA/NCI NIH HHS/United States ; }, mesh = {Ammonium Compounds/metabolism ; Bacillus subtilis/cytology/drug effects/*growth & development/metabolism ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Bioreactors ; Diffusion ; Enzyme Activation/drug effects ; Glutamate Dehydrogenase/metabolism ; Glutamic Acid/metabolism/pharmacology ; Glutamine/biosynthesis ; Lab-On-A-Chip Devices ; Time Factors ; }, abstract = {Cell fate determination is typically regulated by biological networks, yet increasing evidences suggest that cell-cell communication and environmental stresses play crucial roles in the behavior of a cell population. A recent microfluidic experiment showed that the metabolic codependence of two cell populations generates a collective oscillatory dynamic during the expansion of a Bacillus subtilis biofilm. We develop a modeling framework for the spatiotemporal dynamics of the associated metabolic circuit for cells in a colony. We elucidate the role of metabolite diffusion and the need of two distinct cell populations to observe oscillations. Uniquely, this description captures the onset and thereafter stable oscillatory dynamics during expansion and predicts the existence of damping oscillations under various environmental conditions. This modeling scheme provides insights to understand how cells integrate the information from external signaling and cell-cell communication to determine the optimal survival strategy and/or maximize cell fitness in a multicellular system.}, } @article {pmid29608622, year = {2018}, author = {de Souza Araújo, IJ and de Paula, AB and Bruschi Alonso, RC and Taparelli, JR and Innocentini Mei, LH and Stipp, RN and Puppin-Rontani, RM}, title = {A novel Triclosan Methacrylate-based composite reduces the virulence of Streptococcus mutans biofilm.}, journal = {PloS one}, volume = {13}, number = {4}, pages = {e0195244}, pmid = {29608622}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Microscopy, Confocal ; Polyethylene Glycols/*pharmacology ; Polymethacrylic Acids/*pharmacology ; Streptococcus mutans/*drug effects/growth & development/*pathogenicity/physiology ; Virulence ; }, abstract = {The use of antimicrobial monomers, linked to the polymer chain of resin composites, is an interesting approach to circumvent the effects of bacteria on the dental and material surfaces. In addition, it can likely reduce the incidence of recurrent caries lesions. The aim of this study was to evaluate the effects of a novel Triclosan Methacrylate (TM) monomer, which was developed and incorporated into an experimental resin composite, on Streptococcus mutans (S. mutans) biofilms, focusing on the analyses of vicR, gtfD, gtfC, covR, and gbpB gene expression, cell viability and biofilm characteristics. The contact time between TM-composite and S. mutans down-regulated the gbpB and covR and up-regulated the gtfC gene expression, reduced cell viability and significantly decreased parameters of the structure and characteristics of S. mutans biofilm virulence. The presence of Triclosan Methacrylate monomer causes harmful effects at molecular and cellular levels in S. mutans, implying a reduction in the virulence of those microorganisms.}, } @article {pmid29605807, year = {2018}, author = {Kotb, A and Abutaleb, NS and Seleem, MA and Hagras, M and Mohammad, H and Bayoumi, A and Ghiaty, A and Seleem, MN and Mayhoub, AS}, title = {Phenylthiazoles with tert-Butyl side chain: Metabolically stable with anti-biofilm activity.}, journal = {European journal of medicinal chemistry}, volume = {151}, number = {}, pages = {110-120}, pmid = {29605807}, issn = {1768-3254}, support = {R01 AI130186/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/pharmacokinetics/*pharmacology ; Biofilms/*drug effects ; Caco-2 Cells ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Microbial Sensitivity Tests ; Rats, Sprague-Dawley ; Staphylococcal Infections/drug therapy/microbiology ; Thiazoles/*chemistry/pharmacokinetics/*pharmacology ; }, abstract = {A new series of phenylthiazoles with t-butyl lipophilic component was synthesized and their antibacterial activity against a panel of multidrug-resistant bacterial pathogens was evaluated. Five compounds demonstrated promising antibacterial activity against methicillin-resistant staphylococcal strains and several vancomycin-resistant staphylococcal and enterococcal species. Additionally, three derivatives 19, 23 and 26 exhibited rapid bactericidal activity, and remarkable ability to disrupt mature biofilm produced by MRSA USA300. More importantly, a resistant mutant to 19 couldn't be isolated after subjecting MRSA to sub-lethal doses for 14 days. Lastly, this new series of phenylthiazoles possesses an advantageous attribute over the first-generation compounds in their stability to hepatic metabolism, with a biological half-life of more than 9 h.}, } @article {pmid29605781, year = {2018}, author = {De Sotto, R and Ho, J and Lee, W and Bae, S}, title = {Discriminating activated sludge flocs from biofilm microbial communities in a novel pilot-scale reciprocation MBR using high-throughput 16S rRNA gene sequencing.}, journal = {Journal of environmental management}, volume = {217}, number = {}, pages = {268-277}, doi = {10.1016/j.jenvman.2018.03.081}, pmid = {29605781}, issn = {1095-8630}, mesh = {Bacteria/classification/genetics ; *Biofilms ; *Biofouling ; Bioreactors ; Membranes, Artificial ; RNA, Ribosomal, 16S/*analysis ; *Sewage ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Membrane bioreactors (MBRs) are a well-established filtration technology that has become a popular solution for treating wastewater. One of the drawbacks of MBRs, however, is the formation of biofilm on the surface of membrane modules. The occurrence of biofilms leads to biofouling, which eventually compromises water quality and damages the membranes. To prevent this, it is vital to understand the mechanism of biofilm formation on membrane surfaces. In this pilot-scale study, a novel reciprocation membrane bioreactor was operated for a period of 8 months and fed with domestic wastewater from an aerobic tank of a local WWTP. Water quality parameters were monitored and the microbial composition of the attached biofilm and suspended aggregates was evaluated in this reciprocating MBR configuration. The abundance of nitrifiers and composition of microbial communities from biofilm and suspended solids samples were investigated using qPCR and high throughput 16S amplicon sequencing. Removal efficiencies of 29%, 16%, and 15% of chemical oxygen demand, total phosphorus and total nitrogen from the influent were observed after the MBR process with average effluent concentrations of 16 mg/L, 4.6 mg/L, and 5.8 mg/L respectively. This suggests that the energy-efficient MBR, apart from reducing the total energy consumption, was able to maintain effluent concentrations that are within regulatory standards for discharge. Molecular analysis showed the presence of amoA Bacteria and 16S Nitrospira genes with the occurrence of nitrification. Candidatus Accumulibacter, a genus with organisms that can accumulate phosphorus, was found to be present in both groups which explains why phosphorus removal was observed in the system. High-throughput 16S rRNA amplicon sequencing revealed the genus Saprospira to be the most abundant species from the total OTUs of both the membrane tank and biofilm samples.}, } @article {pmid29605650, year = {2018}, author = {Dolatabadi, S and Moghadam, HN and Mahdavi-Ourtakand, M}, title = {Evaluating the anti-biofilm and antibacterial effects of Juglans regia L. extracts against clinical isolates of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {118}, number = {}, pages = {285-289}, doi = {10.1016/j.micpath.2018.03.055}, pmid = {29605650}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Iran ; Juglans/*chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification ; Tracheal Diseases/microbiology ; Uremia/microbiology ; Virulence Factors ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa, an opportunistic pathogen, can cause serious health problems and produces several virulence factors. The most important of these factors is biofilm. Many studies suggest administration of new generation of antibiotics, as P. aeruginosa biofilm has developed high resistance to antimicrobial drugs. Emergence of multidrug resistant (MDR) strains has resulted in screening biofilm inhibitors from natural products or modified from natural compounds. To test this hypothesis, we evaluated the inhibitory effects (antibacterial and antibiofilm) of Juglans regia L. extract on biofilm formation by clinical isolates of P. aeruginosa.

METHODS: Samples collected from burn, tracheal and urine infections of hospitalized patients (Shahid Motahari Hospital, Tehran, Iran) were identified as P. aeruginosa using traditional biochemical tests. Antibiotic susceptibility testing of isolates was performed using disk diffusion method. The microtiter plate method was used to evaluate the ability of pathogenic strains in producing biofilm. Antibacterial and antibiofilm effects of aqueous and methanol Juglans regia L. leaf extracts were determined by microtiter plate method.

RESULTS: 46.7% of P. aeruginosa isolates (n = 50) were resistant to gentamicin and 100% of them could form a biofilm. All isolates (100%) exhibited MDR phenotype. Various concentrations of Juglans regia L. extracts exhibited significant effects on the growth and biofilm inhibition of the isolates. In addition, aqueous Juglans regia L. leaf extract had better inhibition activity on planktonic growth, and methanol extract was more effective on inhibiting biofilm of P. aeruginosa.

CONCLUSIONS: The results of this study indicate that antibiotic-resistant strains were significantly associated with biofilm formation. The J. regia L. extract, at various concentrations, may provide an alternative to control biofilm-related infections caused by P. aeruginosa. Further analyses are needed to validate the antibiofilm activity of these medicinal plants.}, } @article {pmid29604432, year = {2018}, author = {Lépesová, K and Kraková, L and Pangallo, D and Medveďová, A and Olejníková, P and Mackuľak, T and Tichý, J and Grabic, R and Birošová, L}, title = {Prevalence of antibiotic-resistant coliform bacteria, Enterococcus spp. and Staphylococcus spp. in wastewater sewerage biofilm.}, journal = {Journal of global antimicrobial resistance}, volume = {14}, number = {}, pages = {145-151}, doi = {10.1016/j.jgar.2018.03.008}, pmid = {29604432}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/pharmacology ; Azithromycin/pharmacology ; Biofilms/*drug effects/growth & development ; Clarithromycin/pharmacology ; Enterobacteriaceae/*drug effects/genetics/isolation & purification ; Enterococcus/*drug effects/genetics/isolation & purification ; Prevalence ; RNA, Ribosomal, 16S/genetics ; Slovakia ; Staphylococcus/*drug effects/genetics/isolation & purification ; Wastewater/*microbiology ; }, abstract = {OBJECTIVES: Urban wastewater contains various micropollutants and a high number of different micro-organisms. Some bacteria in wastewater can attach to surfaces and form biofilm, which gives bacteria an advantage in the fight against environmental stresses. This work focused on analysis of bacterial communities in biofilms isolated from influent and effluent sewerage of a wastewater treatment plant (WWTP) in Bratislava, Slovakia.

METHODS: Detection of biofilm microbiota was performed by culture-independent and -dependent approaches. The composition of bacterial strains was detected by denaturing gradient gel electrophoresis fingerprinting coupled with construction of 16S rRNA clone libraries. Analysis of the concentration of antibiotics and the prevalence of antibiotic-resistant coliforms, Enterococcus spp. and Staphylococcus spp. in sewerage was also studied.

RESULTS: Biofilm collected at the inlet point was characterised primarily by the presence of Pseudomonas spp., Acinetobacter spp. and Janthinobacterium spp. clones, whilst members of the genus Pseudomonas were largely detected in biofilm isolated in outflow of the WWTP. Predominant antibiotics such as azithromycin, clarithromycin and ciprofloxacin were found in influent wastewater. The removal efficiency of these antibiotics, notably azithromycin and clarithromycin, was 30% in most cases.

CONCLUSION: The highest number of antibiotic-resistant bacteria, with a predominance of coliforms, was detected in samples of effluent biofilm. Multidrug-resistant strains in effluent biofilm showed very good biofilm-forming ability.}, } @article {pmid29603066, year = {2018}, author = {Matsuda, Y and Cho, O and Sugita, T and Ogishima, D and Takeda, S}, title = {Culture Supernatants of Lactobacillus gasseri and L. crispatus Inhibit Candida albicans Biofilm Formation and Adhesion to HeLa Cells.}, journal = {Mycopathologia}, volume = {183}, number = {4}, pages = {691-700}, pmid = {29603066}, issn = {1573-0832}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/physiology ; Cell Adhesion/*drug effects ; Culture Media/*chemistry ; Female ; Formazans/analysis ; HeLa Cells ; Humans ; Lactobacillus crispatus/growth & development/*metabolism ; Lactobacillus gasseri/growth & development/*metabolism ; Microbial Viability/drug effects ; Staining and Labeling ; }, abstract = {PURPOSE: Vulvovaginal candidiasis (VVC) is a common superficial infection of the vaginal mucous membranes caused by the fungus Candida albicans. The aim of this study was to assess the mechanisms underlying the inhibitory effects of the culture supernatants of Lactobacillus gasseri and L. crispatus, the predominant microbiota in Asian healthy women, on C. albicans biofilm formation. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was also investigated.

METHODS: Candida albicans biofilm was formed on polystyrene flat-bottomed 96-well plates, and the inhibitory effects on the initial colonization and maturation phases were determined using the XTT reduction assay. The expression levels of biofilm formation-associated genes (HWP1, ECE1, ALS3, BCR1, EFG1, TEC1, and CPH1) were determined by reverse transcription quantitative polymerase chain reaction. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was evaluated by enumerating viable C. albicans cells.

RESULTS: The culture supernatants of both Lactobacillus species inhibited the initial colonization and maturation of C. albicans biofilm. The expression levels of all biofilm formation-related genes were downregulated in the presence of Lactobacillus culture supernatant. The culture supernatant also inhibited C. albicans adhesion to HeLa cells.

CONCLUSION: The culture supernatants of L. gasseri and L. crispatus inhibited C. albicans biofilm formation by downregulating biofilm formation-related genes and C. albicans adhesion to HeLa cells. These findings support the notion that Lactobacillus metabolites may be useful alternatives to antifungal drugs for the management of VVC.}, } @article {pmid29601791, year = {2018}, author = {Lima, JLDC and Alves, LR and Jacomé, PRLA and Bezerra Neto, JP and Maciel, MAV and Morais, MMC}, title = {Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing.}, journal = {The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases}, volume = {22}, number = {2}, pages = {129-136}, pmid = {29601791}, issn = {1678-4391}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Bacterial Proteins/chemistry/*genetics ; Biofilms/*drug effects/*growth & development ; Cross Infection ; Drug Resistance, Multiple, Bacterial ; Humans ; Polymerase Chain Reaction/methods ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/chemistry/drug effects/*physiology ; Trans-Activators/chemistry/*genetics ; }, abstract = {INTRODUCTION: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts.

OBJECTIVES: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS) genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates.

METHODS: Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR.

RESULTS: The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile) and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain). Alignment analysis showed an insertion of three nucleotides (T, C and G) causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53.

CONCLUSION: The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm.}, } @article {pmid29596620, year = {2018}, author = {Di Pippo, F and Di Gregorio, L and Congestri, R and Tandoi, V and Rossetti, S}, title = {Biofilm growth and control in cooling water industrial systems.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {5}, pages = {}, doi = {10.1093/femsec/fiy044}, pmid = {29596620}, issn = {1574-6941}, mesh = {Biofilms/*growth & development ; Fresh Water/*microbiology ; Legionella pneumophila/*physiology ; Water Microbiology ; Water Supply ; }, abstract = {Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure. A broad evaluation of the most relevant biofilm monitoring and control strategies currently used or potentially useful in cooling water systems is also provided.}, } @article {pmid29595151, year = {2018}, author = {Han, YM and Liu, FX and Xu, XF and Yan, Z and Liu, ZJ}, title = {Nitrogen removal via a single-stage PN-Anammox process in a novel combined biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {5-6}, pages = {1483-1492}, doi = {10.2166/wst.2017.572}, pmid = {29595151}, issn = {0273-1223}, mesh = {Ammonia/chemistry/*metabolism ; Bacteria/genetics/metabolism ; *Biofilms ; Bioreactors/*microbiology ; Denitrification ; In Situ Hybridization, Fluorescence ; Microscopy, Electron, Scanning ; Nitrification ; Nitrogen/chemistry/*metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/methods ; Wastewater/*chemistry ; Water Pollutants, Chemical/chemistry/metabolism ; }, abstract = {This study developed a partial nitrification (PN) and anaerobic ammonia oxidation (Anammox) process for treating high-ammonia wastewater using an innovative biofilm system in which ammonia oxidizing bacteria grew on fluidized Kaldnes (K1) carriers and Anammox bacteria grew on fixed acryl resin carriers. The airlift loop biofilm reactor (ALBR) was stably operated for more than 4 months under the following conditions: 35 ± 2 °C, pH 7.5-8.0 and dissolved oxygen (DO) of 0.5-3.5 mg/L. The results showed that the total nitrogen removal efficiency reached a maximum of 75% and the total nitrogen removal loading rate was above 0.4 kg/(d·m[3]). DO was the most efficient control parameter in the mixed biofilm system, and values below 1.5 mg/L were observed in the riser zone for the PN reaction, while values below 0.8 mg/L were observed in the downer zone for the Anammox reaction. Scanning electron microscopy and Fluorescence In Situ Hybridization images showed that most of the nitrifying bacteria were distributed on the K1 carriers and most of the Anammox bacteria were distributed within the acryl resin carriers. Therefore, the results indicate that the proposed combined biofilm system is easy to operate and efficient for the treatment of high-ammonia wastewater.}, } @article {pmid29593796, year = {2018}, author = {Ampornaramveth, RS and Akeatichod, N and Lertnukkhid, J and Songsang, N}, title = {Application of D-Amino Acids as Biofilm Dispersing Agent in Dental Unit Waterlines.}, journal = {International journal of dentistry}, volume = {2018}, number = {}, pages = {9413925}, pmid = {29593796}, issn = {1687-8728}, abstract = {AIM AND PURPOSE: Biofilms in dental unit waterlines (DUWLs) are extremely difficult to eliminate. Aim of this study is to evaluate the efficacy of a mixture of four D-amino acids on biofilm dispersion in DUWLs.

MATERIALS AND METHODS: A mixture of four D-amino acids (D-methionine, D-tryptophan, D-leucine, and D-tyrosine, 10 mM each), distilled water (control), and 0.1 M hydrochloric acid (HCl) was used in the experiment. In laboratory, pieces of DUWLs covered with biofilms were submerged in different solutions for 5 days, flushed, and measured OD[600] of the dispersed biofilms. Remnants of biofilms on the DUWLs were evaluated by SEM. In clinic, fifteen DCUs were incubated with test and control solutions, flushed, and measured OD[600] of the dispersed biofilms. Microbial count of DUWL output water was enumerated twice a week for four weeks.

RESULTS: There was a slight, but not significant, increase in OD[600] of flushing water in D-amino acids group. D-amino acids effectively reduced bacterial plaque as demonstrated by SEM. Incubation with D-amino acids significantly reduced biofilms especially after the first day of flushing. Bacterial count in DUWL output water was significantly reduced after treatment with D-amino acids.

CONCLUSION: D-amino acids are applicable as biofilm dispersing agents in DUWLs.}, } @article {pmid29593793, year = {2018}, author = {Alvarez-Escobar, M and Freitas, SC and Hansford, D and Monteiro, FJ and Pelaez-Vargas, A}, title = {Soft Lithography and Minimally Human Invasive Technique for Rapid Screening of Oral Biofilm Formation on New Microfabricated Dental Material Surfaces.}, journal = {International journal of dentistry}, volume = {2018}, number = {}, pages = {4219625}, pmid = {29593793}, issn = {1687-8728}, abstract = {INTRODUCTION: Microfabrication offers opportunities to study surface concepts focused to reduce bacterial adhesion on implants using human minimally invasive rapid screening (hMIRS). Wide information is available about cell/biomaterial interactions using eukaryotic and prokaryotic cells on surfaces of dental materials with different topographies, but studies using human being are still limited.

OBJECTIVE: To evaluate a synergy of microfabrication and hMIRS to study the bacterial adhesion on micropatterned surfaces for dental materials.

MATERIALS AND METHODS: Micropatterned and flat surfaces on biomedical PDMS disks were produced by soft lithography. The hMIRS approach was used to evaluate the total oral bacterial adhesion on PDMS surfaces placed in the oral cavity of five volunteers (the study was approved by the University Ethical Committee). After 24 h, the disks were analyzed using MTT assay and light microscopy.

RESULTS: In the present pilot study, microwell structures were microfabricated on the PDMS surface via soft lithography with a spacing of 5 µm. Overall, bacterial adhesion did not significantly differ between the flat and micropatterned surfaces. However, individual analysis of two subjects showed greater bacterial adhesion on the micropatterned surfaces than on the flat surfaces.

SIGNIFICANCE: Microfabrication and hMIRS might be implemented to study the cell/biomaterial interactions for dental materials.}, } @article {pmid29593544, year = {2018}, author = {Ding, W and Sun, J and Lian, H and Xu, C and Liu, X and Zheng, S and Zhang, D and Han, X and Liu, Y and Chen, X and God Spower, BO and Li, Y}, title = {The Influence of Shuttle-Shape Emodin Nanoparticles on the Streptococcus suis Biofilm.}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {227}, pmid = {29593544}, issn = {1663-9812}, abstract = {Biofilm is one of the most important physiological protective barriers of the Streptococcus suis (S. suis), and it is also one of the primary causes of hindrance to drug infiltration, reduction of bactericidal effects, and the development of antibiotic resistance. In order to intervene or eliminate S. suis biofilm, shuttle-shape emodin-loaded nanoparticles were developed in our study. The emodin nanoparticles were prepared by emodin and gelatin-cyclodextrin which was synthesized as drug carrier, and the nanoparticles were 174 nm in size, -4.64 mv in zeta potential, and exhibited a sustained emodin release. Moreover, the delivery kinetics of nanoparticles were also explored in our study. The confocal laser scanning microscopy and colony forming unit enumeration experiment indicated that nanoparticles could increase drug infiltration and uptake by biofilm. The flow cytometry system analysis showed that nanoparticles could be up taken by 99% of the bacteria cells. TCP assay and scanning electron microscopy showed that the nanoparticles had better effect on biofilm inhibition and elimination when compared with emodin solution. These results revealed that the emodin nanoparticles had a better therapeutic effect on the S. suis biofilm in vitro.}, } @article {pmid29593289, year = {2018}, author = {Acemel, RD and Govantes, F and Cuetos, A}, title = {Computer simulation study of early bacterial biofilm development.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {5340}, pmid = {29593289}, issn = {2045-2322}, mesh = {Algorithms ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Computer Simulation ; *Models, Biological ; }, abstract = {Most bacteria form organized sessile communities, known as biofilms. Their ubiquity and relevance have stimulated the development of efficient mathematical models able to predict biofilm evolution and characteristics at different conditions. Here we present a study of the early stages of bacterial biofilm formation modeled by means of individual cell-based computer simulation. Simulation showed that clusters with different degrees of internal and orientational order were formed as a function of the aspect ratio of the individual particles and the relation between the diffusion and growth rates. Analysis of microscope images of early biofilm formation by the Gram-negative bacterium Pseudomonas putida at varying diffusion rates revealed a good qualitative agreement with the simulation results. Our model is a good predictor of microcolony morphology during early biofilm development, showing that the competition between diffusion and growth rates is a key aspect in the formation of stable biofilm microcolonies.}, } @article {pmid29589446, year = {2018}, author = {Nguyen, CQ and Thrift, WJ and Bhattacharjee, A and Ranjbar, S and Gallagher, T and Darvishzadeh-Varcheie, M and Sanderson, RN and Capolino, F and Whiteson, K and Baldi, P and Hochbaum, AI and Ragan, R}, title = {Longitudinal Monitoring of Biofilm Formation via Robust Surface-Enhanced Raman Scattering Quantification of Pseudomonas aeruginosa-Produced Metabolites.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {15}, pages = {12364-12373}, doi = {10.1021/acsami.7b18592}, pmid = {29589446}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Limit of Detection ; Pseudomonas aeruginosa ; Spectrum Analysis, Raman ; }, abstract = {Detection of bacterial metabolites at low concentrations in fluids with complex background allows for applications ranging from detecting biomarkers of respiratory infections to identifying contaminated medical instruments. Surface-enhanced Raman scattering (SERS) spectroscopy, when utilizing plasmonic nanogaps, has the relatively unique capacity to reach trace molecular detection limits in a label-free format, yet large-area device fabrication incorporating nanogaps with this level of performance has proven difficult. Here, we demonstrate the advantages of using chemical assembly to fabricate SERS surfaces with controlled nanometer gap spacings between plasmonic nanospheres. Control of nanogap spacings via the length of the chemical crosslinker provides uniform SERS signals, exhibiting detection of pyocyanin, a secondary metabolite of Pseudomonas aeruginosa, in aqueous media at concentration of 100 pg·mL[-1]. When using machine learning algorithms to analyze the SERS data of the conditioned medium from a bacterial culture, having a more complex background, we achieve 1 ng·mL[-1] limit of detection of pyocyanin and robust quantification of concentration spanning 5 orders of magnitude. Nanogaps are also incorporated in an in-line microfluidic device, enabling longitudinal monitoring of P. aeruginosa biofilm formation via rapid pyocyanin detection in a medium effluent as early as 3 h after inoculation and quantification in under 9 h. Surface-attached bacteria exposed to a bactericidal antibiotic were differentially less susceptible after 10 h of growth, indicating that these devices may be useful for early intervention of bacterial infections.}, } @article {pmid29588402, year = {2018}, author = {Townsley, L and Yannarell, SM and Huynh, TN and Woodward, JJ and Shank, EA}, title = {Cyclic di-AMP Acts as an Extracellular Signal That Impacts Bacillus subtilis Biofilm Formation and Plant Attachment.}, journal = {mBio}, volume = {9}, number = {2}, pages = {}, pmid = {29588402}, issn = {2150-7511}, support = {R01 GM112981/GM/NIGMS NIH HHS/United States ; P30 CA016086/CA/NCI NIH HHS/United States ; }, mesh = {Arabidopsis/*metabolism/*microbiology ; Bacillus subtilis/genetics/*metabolism/*physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic AMP/*metabolism ; Plant Roots/metabolism/microbiology ; }, abstract = {There is a growing appreciation for the impact that bacteria have on higher organisms. Plant roots often harbor beneficial microbes, such as the Gram-positive rhizobacterium Bacillus subtilis, that influence their growth and susceptibility to disease. The ability to form surface-attached microbial communities called biofilms is crucial for the ability of B. subtilis to adhere to and protect plant roots. In this study, strains harboring deletions of the B. subtilis genes known to synthesize and degrade the second messenger cyclic di-adenylate monophosphate (c-di-AMP) were examined for their involvement in biofilm formation and plant attachment. We found that intracellular production of c-di-AMP impacts colony biofilm architecture, biofilm gene expression, and plant attachment in B. subtilis We also show that B. subtilis secretes c-di-AMP and that putative c-di-AMP transporters impact biofilm formation and plant root colonization. Taken together, our data describe a new role for c-di-AMP as a chemical signal that affects important cellular processes in the environmentally and agriculturally important soil bacterium B. subtilis These results suggest that the "intracellular" signaling molecule c-di-AMP may also play a previously unappreciated role in interbacterial cell-cell communication within plant microbiomes.IMPORTANCE Plants harbor bacterial communities on their roots that can significantly impact their growth and pathogen resistance. In most cases, however, the signals that mediate host-microbe and microbe-microbe interactions within these communities are unknown. A detailed understanding of these interaction mechanisms could facilitate the manipulation of these communities for agricultural or environmental purposes. Bacillus subtilis is a plant-growth-promoting bacterium that adheres to roots by forming biofilms. We therefore began by exploring signals that might impact its biofilm formation. We found that B. subtilis secretes c-di-AMP and that the ability to produce, degrade, or transport cyclic di-adenylate monophosphate (c-di-AMP; a common bacterial second messenger) affects B. subtilis biofilm gene expression and plant attachment. To our knowledge, this is the first demonstration of c-di-AMP impacting a mutualist host-microbe association and suggests that c-di-AMP may function as a previously unappreciated extracellular signal able to mediate interactions within plant microbiomes.}, } @article {pmid29587179, year = {2018}, author = {Ahmed, HA and El Bayomi, RM and Hussein, MA and Khedr, MHE and Abo Remela, EM and El-Ashram, AMM}, title = {Molecular characterization, antibiotic resistance pattern and biofilm formation of Vibrio parahaemolyticus and V. cholerae isolated from crustaceans and humans.}, journal = {International journal of food microbiology}, volume = {274}, number = {}, pages = {31-37}, doi = {10.1016/j.ijfoodmicro.2018.03.013}, pmid = {29587179}, issn = {1879-3460}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Crustacea/*microbiology ; *Drug Resistance, Microbial ; Egypt ; Feces/*microbiology ; Humans ; Seafood/microbiology ; *Vibrio cholerae/drug effects/genetics/physiology ; *Vibrio parahaemolyticus/drug effects/genetics/physiology ; }, abstract = {Human infection with pathogenic vibrios is associated with contaminated seafood consumption. In the present study, we examined 225 crustaceans collected from retail markets in Egypt. Stool samples from gastroenteritis patients were also examined. Bacteriological and molecular examinations revealed 34 (15.1%) V. parahaemolyticus and 2 (0.9%) V. cholerae from crustaceans, while V. parahaemolyticus isolates were identified in 3 (3%) of the human samples. The virulence-associated genes tdh and/or trh were detected in 5.9% and 100% of the crustacean and human samples, respectively, whereas the two V. cholerae isolates were positive for the ctx and hlyA genes. Antibiotic sensitivity revealed high resistance of the isolates to the used antibiotics and an average MAR index of 0.77. Biofilm formation at different temperatures indicated significantly higher biofilm formation at 37 °C and 25 °C compared with 4 °C. Frequent monitoring of seafood for Vibrio species and their antibiotic, molecular and biofilm characteristics is essential to improve seafood safety.}, } @article {pmid29580624, year = {2018}, author = {De, A and Pompilio, A and Francis, J and Sutcliffe, IC and Black, GW and Lupidi, G and Petrelli, D and Vitali, LA}, title = {Antidiabetic "gliptins" affect biofilm formation by Streptococcus mutans.}, journal = {Microbiological research}, volume = {209}, number = {}, pages = {79-85}, doi = {10.1016/j.micres.2018.02.005}, pmid = {29580624}, issn = {1618-0623}, mesh = {Adamantane/analogs & derivatives/metabolism ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Dental Caries/microbiology/*prevention & control ; Dipeptides/metabolism ; Dipeptidyl-Peptidase IV Inhibitors/pharmacology ; Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/genetics/*metabolism ; Microbial Sensitivity Tests ; Proteomics ; Streptococcus mutans/*genetics/*pathogenicity ; Virulence/genetics ; }, abstract = {Streptococcus mutans, a dental caries causing odontopathogen, produces X-prolyl dipeptidyl peptidase (Sm-XPDAP, encoded by pepX), a serine protease known to have a nutritional role. Considering the potential of proteases as therapeutic targets in pathogens, this study was primarily aimed at investigating the role of Sm-XPDAP in contributing to virulence-related traits. Dipeptidyl peptidase (DPP IV), an XPDAP analogous enzyme found in mammalian tissues,is a well known therapeutic target in Type II diabetes. Based on the hypothesis that gliptins, commonly used as anti-human-DPP IV drugs, may affect bacterial growth upon inhibition of Sm-XPDAP, we have determined their ex vivo antimicrobial and anti-biofilm activity towards S. mutans. All three DPP IV drugs tested reduced biofilm formation as determined by crystal violet staining. To link the observed biofilm inhibition to the human-DPP IV analogue present in S. mutans UA159, a pepX isogenic mutant was generated. In addition to reduced biofilm formation, CLSM studies of the biofilm formed by the pepX isogenic mutant showed these were comparable to those formed in the presence of saxagliptin, suggesting a probable role of this enzyme in biofilm formation by S. mutans UA159. The effects of both pepX deletion and DPP IV drugs on the proteome were studied using LC-MS/MS. Overall, this study highlights the potential of Sm-XPDAP as a novel anti-biofilm target and suggests a template molecule to synthesize lead compounds effective against this enzyme.}, } @article {pmid29580499, year = {2018}, author = {Ju, X and Li, J and Zhu, M and Lu, Z and Lv, F and Zhu, X and Bie, X}, title = {Effect of the luxS gene on biofilm formation and antibiotic resistance by Salmonella serovar Dublin.}, journal = {Food research international (Ottawa, Ont.)}, volume = {107}, number = {}, pages = {385-393}, doi = {10.1016/j.foodres.2018.02.039}, pmid = {29580499}, issn = {1873-7145}, mesh = {Bacterial Proteins/drug effects/*genetics ; Biofilms/*drug effects ; Carbon-Sulfur Lyases/drug effects/*genetics ; Drug Resistance, Microbial/drug effects/*genetics ; Gene Expression Regulation, Bacterial/*genetics ; Quorum Sensing/drug effects/genetics ; Salmonella/*drug effects/*genetics ; }, abstract = {Biofilms are communities of bacterial cells that serve to protect them from external adverse influences and enhance bacterial resistance to antibiotics and sanitizers. Here, we studied the regulatory effects of glucose and sodium chloride on biofilm formation in Salmonella serovar Dublin (S. Dublin). To analyze expression levels of the quorum sensing gene luxS, we created a luxS knockout mutant. Also, antimicrobial resistance, hydrophobicity and autoinducer-2 (AI-2) activity of both the wild-type (WT) and the mutant strain were investigated. Our results revealed that glucose was not essential for S. Dublin biofilm formation but had an inhibitory effect on biofilm formation when the concentration was over 0.1%. NaCl was found to be indispensable in forming biofilm, and it also exerted an inhibitory effect at high concentrations (>1.0%). Both the WT and the mutant strains displayed significant MIC growth after biofilm formation. An increase of up to 32,768 times in the resistance of S. Dublin in biofilm phonotype against antibiotic (ampicillin) compared to its planktonic phonotype was observed. However, S. Dublin luxS knockout mutant only showed slight differences compared to the WT strain in the antimicrobial tests although it displayed better biofilm-forming capacity than the WT strain. The mutant strain also exhibited higher hydrophobicity than the WT strain, which was a feature related to biofilm formation. The production of the quorum sensing autoinducer-2 (AI-2) was significantly lower in the mutant strain than in the WT strain since the LuxS enzyme, encoded by the luxS gene, plays an essential role in AI-2 synthesis. However, the limited biofilm-forming ability in the WT strain indicated AI-2 was not directly related to S. Dublin biofilm formation. Furthermore, gene expression analysis of the WT and mutant strains revealed upregulation of genes related to biofilm stress response and enhanced resistance in the luxS mutant strain, which may provide evidence for the regulatory role of the luxS gene in biofilm formation.}, } @article {pmid29580466, year = {2018}, author = {Iliadis, I and Daskalopoulou, A and Simões, M and Giaouris, E}, title = {Integrated combined effects of temperature, pH and sodium chloride concentration on biofilm formation by Salmonella enterica ser. Enteritidis and Typhimurium under low nutrient food-related conditions.}, journal = {Food research international (Ottawa, Ont.)}, volume = {107}, number = {}, pages = {10-18}, doi = {10.1016/j.foodres.2018.02.015}, pmid = {29580466}, issn = {1873-7145}, mesh = {Biofilms/*drug effects/growth & development ; Food Microbiology/*methods ; Hydrogen-Ion Concentration ; Models, Theoretical ; Salinity ; Salmonella Food Poisoning/*microbiology/prevention & control ; Salmonella enterica/*drug effects/growth & development/metabolism ; Salmonella typhimurium/*drug effects/growth & development/metabolism ; Sodium Chloride/*pharmacology ; *Temperature ; Time Factors ; }, abstract = {Salmonella enterica is a major foodborne bacterial pathogen. This forms biofilms on surfaces and persists, depending on the strain and the environment. The integrative interaction of temperature (T; 13-39 °C), pH (5-8) and sodium chloride (NaCl) concentration (0.5-8.5%) on biofilm formation by two S. enterica strains (ser. Enteritidis and Typhimurium) was here evaluated under low nutrient conditions. This was achieved using response surface methodology to model the combined effect of each factor on the response, through mathematical quadratic fitting of the outcomes of a sequence of designed experiments. These last were executed by incubating stainless steel coupons carrying sessile bacteria, for 24 h, in 1:10 diluted tryptone soya broth, under 15 different combinations of three independent factors (T, pH and NaCl). For each strain, a second order polynomial model, describing the relationship between biofilm formation (log CFU/cm[2]) and the factors (T, pH and NaCl), was developed using least square regression analysis. Both derived models predicted the combined influences of these factors on biofilm formation, with agreement between predictions and experimental observations (R[2] ≥ 0.96, P ≤ 0.0001). For both strains, the increase of NaCl content restricted their sessile growth, while under low salinity conditions (NaCl < 4%) biofilm formation was favored as pH increased, regardless of T. Interestingly, under low salt content, and depending on the strain, biofilm formation was either favored or hindered by increasing T. Thus, 34.5 and 13 °C were the T predicted to maximize biofilm formation by strains Enteritidis and Typhimurium, respectively, something which was also experimentally verified. To sum, these models can predict the interactive influences of crucial food-related factors on biofilm growth of a significant foodborne pathogen towards the efforts to limit its persistence in food industry.}, } @article {pmid29579106, year = {2018}, author = {Anutrakunchai, C and Bolscher, JGM and Krom, BP and Kanthawong, S and Chareonsudjai, S and Taweechaisupapong, S}, title = {Impact of nutritional stress on drug susceptibility and biofilm structures of Burkholderia pseudomallei and Burkholderia thailandensis grown in static and microfluidic systems.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0194946}, pmid = {29579106}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; Burkholderia/chemistry/growth & development/*physiology ; Burkholderia pseudomallei/chemistry/growth & development/physiology ; Ceftazidime/pharmacology ; Doxycycline/pharmacology ; Drug Resistance, Bacterial ; Food ; Meropenem ; Microbial Sensitivity Tests ; Microfluidics/*methods ; Microscopy, Confocal ; Thienamycins/pharmacology ; Time-Lapse Imaging ; }, abstract = {Burkholderia pseudomallei is the causative agent of melioidosis and regarded as a bioterrorism threat. It can adapt to the nutrient-limited environment as the bacteria can survive in triple distilled water for 16 years. Moreover, B. pseudomallei exhibits intrinsic resistance to diverse groups of antibiotics in particular while growing in biofilms. Recently, nutrient-limited condition influenced both biofilm formation and ceftazidime (CAZ) tolerance of B. pseudomallei were found. However, there is no information about how nutrient-limitation together with antibiotics used in melioidosis treatment affects the structure of the biofilm produced by B. pseudomallei. Moreover, no comparative study to investigate the biofilm architectures of B. pseudomallei and the related B. thailandensis under different nutrient concentrations has been reported. Therefore, this study aims to provide new information on the effects of four antibiotics used in melioidosis treatment, viz. ceftazidime (CAZ), imipenem (IMI), meropenem (MEM) and doxycycline (DOX) on biofilm architecture of B. pseudomallei and B. thailandensis with different nutrient concentrations under static and flow conditions using confocal laser scanning microscopy. Impact of nutritional stress on drug susceptibility of B. pseudomallei and B. thailandensis grown planktonically or as biofilm was also evaluated. The findings of this study indicate that nutrient-limited environment enhanced survival of B. pseudomallei in biofilm after exposure to the tested antibiotics. The shedding planktonic B. pseudomallei and B. thailandensis were also found to have increased CAZ tolerance in nutrient-limited environment. However, killing activities of MEM and IMI were stronger than CAZ and DOX on B. pseudomallei and B. thailandensis both in planktonic cells and in 2-day old biofilm. In addition, MEM and IMI were able to inhibit B. pseudomallei and B. thailandensis biofilm formation to a larger extend compared to CAZ and DOX. Differences in biofilm architecture were observed for biofilms grown under static and flow conditions. Under static conditions, biofilms grown in full strength modified Vogel and Bonner's medium (MVBM) showed honeycomb-like architecture while a knitted-like structure was observed under limited nutrient condition (0.1×MVBM). Under flow conditions, biofilms grown in MVBM showed a multilayer structure while merely dispersed bacteria were found when grown in 0.1×MVBM. Altogether, this study provides more insight on the effect of four antibiotics against B. pseudomallei and B. thailandensis in biofilm under different nutrient and flow conditions. Since biofilm formation is believed to be involved in disease relapse, MEM and IMI may be better therapeutic options than CAZ for melioidosis treatment.}, } @article {pmid29578065, year = {2018}, author = {Borges, KA and Furian, TQ and de Souza, SN and Menezes, R and de Lima, DA and Fortes, FBB and Salle, CTP and Moraes, HLS and Nascimento, VP}, title = {Biofilm formation by Salmonella Enteritidis and Salmonella Typhimurium isolated from avian sources is partially related with their in vivo pathogenicity.}, journal = {Microbial pathogenesis}, volume = {118}, number = {}, pages = {238-241}, doi = {10.1016/j.micpath.2018.03.039}, pmid = {29578065}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/genetics ; Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Fimbriae Proteins/genetics ; Genes, Bacterial/*genetics ; Poultry/microbiology ; Poultry Diseases/microbiology ; Salmonella Infections, Animal ; Salmonella enteritidis/*genetics/*pathogenicity ; Salmonella typhimurium/*genetics/*pathogenicity ; Serogroup ; Temperature ; Virulence/genetics ; Virulence Factors/*genetics ; }, abstract = {Salmonella Enteritidis and Salmonella Typhimurium are among the most prevalent serotypes isolated from salmonellosis outbreaks and poultry. Salmonella spp. have the capacity to form biofilms on several surfaces, which can favour survival in hostile environments, such as slaughterhouses. Salmonella strains present differences in pathogenicity. However, there is little information regarding the pathogenicity of S. Enteritidis and S. Typhimurium isolated from avian sources and their relationship to biofilm production. The aim of this study was to use a novel pathogenicity index and a biofilm production assay to evaluate their relationships within these serotypes. In addition, we detected the presence of the spiA and agfA genes in these strains. Biofilm formation was investigated at two temperatures (37 °C and 28 °C) using microtiter plate assay, and the results were compared with the individual pathogenicity index of each strain. PCR was used to detect spiA and agfA, virulence genes associated with biofilm production. S. Enteritidis and S. Typhimurium strains were capable of producing biofilm at 37 °C and 28 °C. Sixty-two percent and 59.5% of S. Enteritidis and 73.8% and 46.2% of S. Typhimurium produced biofilm at 37 °C and 28 °C, respectively. Biofilm production at 37 °C was significantly higher in both serotypes. Only S. Enteritidis was capable of adhering strongly at both temperatures. Biofilm production was related to pathogenicity index only at 28 °C for S. Enteritidis. spiA and agfA were found in almost all strains and were not statistically associated with biofilm production.}, } @article {pmid29577038, year = {2018}, author = {Choi, AY and Jalikis, F and Westerhoff, M and Boukhar, S and Pulcini, E and Damman, C and Yu, L}, title = {Searching for Bacterial Biofilm in Recurrent Cholangitis in Primary Sclerosing Cholangitis: A Case Presentation and Introduction of an Unexplored Disease Mechanism.}, journal = {Journal of clinical and translational hepatology}, volume = {6}, number = {1}, pages = {114-118}, pmid = {29577038}, issn = {2225-0719}, abstract = {Inflammation and fibrosis of the bile ducts are the defining pathological characteristics of primary sclerosing cholangitis (PSC). A previously unexplored mechanism for recurrent cholangitis, one of PSC's most common presentations, is bacterial colonization of the biliary epithelium in the form of biofilm, which may confer resistance to antibiotics and host phagocytic machinery. The aim of the current study was to assess whether bacteria could be seen on the liver explant and whether they organized in the form of biofilm. An explanted PSC liver from a 60-year-old male who suffered from recurrent cholangitis was formalin-fixed, paraffin-embedded and Gram stained. The specimens were observed under light microscopy. Neither bacteria nor biofilm were detected. We did not detect bacteria or biofilm in the liver explant of a single PSC patient with recurrent cholangitis using standard light microscopy. We suspect this may be in part due to techniques related to tissue preservation and microscopy.}, } @article {pmid29575515, year = {2018}, author = {Guo, S and Langelaan, DN and Phippen, SW and Smith, SP and Voets, IK and Davies, PL}, title = {Conserved structural features anchor biofilm-associated RTX-adhesins to the outer membrane of bacteria.}, journal = {The FEBS journal}, volume = {285}, number = {10}, pages = {1812-1826}, doi = {10.1111/febs.14441}, pmid = {29575515}, issn = {1742-4658}, support = {106612//CIHR/Canada ; }, mesh = {Adhesins, Bacterial/*chemistry ; Amino Acid Sequence ; *Biofilms ; Calcium/chemistry ; Computational Biology ; *Conserved Sequence ; Hydrophobic and Hydrophilic Interactions ; Magnesium/chemistry ; Marinomonas/*chemistry ; Periplasm/chemistry ; Protein Conformation ; Proteolysis ; }, abstract = {Repeats-in-toxin (RTX) adhesins are present in many Gram-negative bacteria to facilitate biofilm formation. Previously, we reported that the 1.5-MDa RTX adhesin (MpIBP) from the Antarctic bacterium, Marinomonas primoryensis, is tethered to the bacterial cell surface via its N-terminal Region I (RI). Here, we show the detailed structural features of RI. It has an N-terminal periplasmic retention domain (RIN), a central domain (RIM) that can insert into the β-barrel of an outer-membrane pore protein during MpIBP secretion, and three extracellular domains at its C terminus (RIC) that transition the protein into the extender region (RII). RIN has a novel β-sandwich fold with a similar shape to βγ-crystallins and tryptophan RNA attenuation proteins. Because RIM undergoes fast and extensive degradation in vitro, its narrow cylindrical shape was rapidly measured by small-angle X-ray scattering before proteolysis could occur. The crystal structure of RIC comprises three tandem β-sandwich domains similar to those in RII, but increasing in their hydrophobicity with proximity to the outer membrane. In addition, the key Ca[2+] ion that rigidifies the linkers between RII domains is not present between the first two of these RIC domains. This more flexible RI linker near the cell surface can act as a 'pivot' to help the 0.6-μm-long MpIBP sweep over larger volumes to find its binding partners. Since the physical features of RI are well conserved in the RTX adhesins of many Gram-negative bacteria, our detailed structural and bioinformatic analyses serve as a model for investigating the surface retention of biofilm-forming bacteria, including human pathogens.}, } @article {pmid29575083, year = {2018}, author = {Bennour Hennekinne, R and Guillier, L and Fazeuilh, L and Ells, T and Forsythe, S and Jackson, E and Meheut, T and Gnanou Besse, N}, title = {Survival of Cronobacter in powdered infant formula and their variation in biofilm formation.}, journal = {Letters in applied microbiology}, volume = {66}, number = {6}, pages = {496-505}, doi = {10.1111/lam.12879}, pmid = {29575083}, issn = {1472-765X}, mesh = {Biofilms/*growth & development ; Cronobacter sakazakii/genetics/*growth & development ; Desiccation ; Enterobacteriaceae Infections/microbiology ; Food Microbiology ; Humans ; Infant ; Infant Formula/*microbiology ; }, abstract = {UNLABELLED: Cronobacter is a ubiquitous Gram-negative pathogen bacterium capable of surviving in low water activity environments, in particular powdered infant formula (PIF). Seven Cronobacter strains representing four different species (C. sakazakii, n = 4; C. malonaticus, n = 1; C. muytjensii, n = 1; C. turicensis, n = 1) were subjected to dry stress and stored in PIF at room temperature. The resulting survivor curves showed that Cronobacter sp. can survive for extended periods of at least 3 months with a significant, but moderate, variability regarding the level of resistance between species; however, no correlation was evident regarding the origin of strains. These results are evaluated with regard to other key characteristics, including genomic profiles and biofilm formation capacities of the strains.

Cronobacter can survive extended periods of at least 3 months in PIF, with moderately significant interspecific variability in desiccation resistance. Results are evaluated with regard to genomic profiles and biofilm formation capacities of the strains, and contribute to an improved understanding of the environmental persistence of Cronobacter in contaminated PIF, and subsequent risk to infant exposure.}, } @article {pmid29573683, year = {2018}, author = {Jing, H and Sahle-Demessie, E and Sorial, GA}, title = {Inhibition of biofilm growth on polymer-MWCNTs composites and metal surfaces.}, journal = {The Science of the total environment}, volume = {633}, number = {}, pages = {167-178}, doi = {10.1016/j.scitotenv.2018.03.065}, pmid = {29573683}, issn = {1879-1026}, abstract = {There is an increased interest in incorporating multi-wall carbon nanotubes (MWCNTs) into polymer matrices to control the adhesion of bacteria to surfaces and the subsequent formation of biofilm growth on the surface of water pipes, food packages, and medical devices. Microbial interactions with carbon nanotube-polymer composites in the environment are not well understood. The growth of Pseudomonas fluorescens (gram-negative) and Mycobacterium smegmatis (gram-positive) biofilms on copper, polyethylene (PE), polyvinyl chloride, and stainless steel was compared with growth on MWCNT-PE composites in order to gain insight into the effect of the surface properties of nanomaterials on the attachment and proliferation of microorganism which could result in the engineering of better, non-fouling materials. A statistical analysis of the biofilm growth showed a significant impact of materials for both P. fluorescens (p < 0.0001) and M. smegmatis (p = 0.00426). Biofilm growth after 56 days on PE compared to biofilm growth on copper surfaces decreased by 46.4% and 34.9% for P. fluorescens and M. smegmatis, respectively. Biofilm growth on PE-multiwall-carbon-nanotubes (MWCNTs)-composites surface compared to PE decreased by 89.3% and 29% for P. fluorescens and M. smegmatis, respectively. Bacterial species (p < 0.0006) and surface roughness (p < 0.0001) were important factors in determining the attachment and initial biofilm growth rate. The interactions between cells and material surface could be attributed to the complicated and collective effect of electrostatic forces, hydrophobic interactions, and hydrogen/covalent bonding. Further study is needed to determine whether or not there is a difference between the cell attachment in the exponential growth phase and the stationary, or decay, phase cells.}, } @article {pmid29573511, year = {2018}, author = {Veerabadhran, M and Chakraborty, S and Mitra, S and Karmakar, S and Mukherjee, J}, title = {Effects of flask configuration on biofilm growth and metabolites of intertidal Cyanobacteria isolated from a mangrove forest.}, journal = {Journal of applied microbiology}, volume = {125}, number = {1}, pages = {190-202}, doi = {10.1111/jam.13761}, pmid = {29573511}, issn = {1365-2672}, mesh = {Biofilms/*growth & development ; Bioreactors/*microbiology ; Cell Culture Techniques/instrumentation ; *Cyanobacteria/growth & development/metabolism ; *Plankton/growth & development/metabolism ; Wetlands ; }, abstract = {AIMS: A novel approach was employed to study the growth of three cyanobacterial strains namely Oscillatoria sp. (AP17), Leptolyngbya sp. (AP3b) and Chroococcus sp. (AP3U). Furthermore, their broad metabolite profile, production of pigments, exopolysaccharide (EPS) and antimicrobial activity were evaluated in response to contrasting cultivation modes: biofilm or planktonic.

METHODS AND RESULTS: The biofilm culture mode was carried out in the patented conico-cylindrical flask (CCF) and the planktonic culture mode was carried out in an Erlenmeyer flask (EF). The amount of polysaccharide that was released and that remained capsular/bound was higher in CCF compared to EF cultivation. Amount of chlorophyll a produced by Oscillatoria (AP17) was higher in the CCF compared to the EF cultivation. Highest antimicrobial activities were exhibited by Leptolyngbya (AP3b) biofilm than other biofilms as well as planktonic biomass. Metabolite profiles of Cyanobacteria were revealed by various chromatographic techniques and showed clear differences among the two contrasting modes of cultivation.

CONCLUSIONS: The results showed clear differences in the mode of growth for achieving maximum chlorophyll a, EPS and bioactive metabolite production of the Cyanobacteria.

The present study augmented the information which can enhance wider exploration of the biofilm mode of cultivation of Cyanobacteria.}, } @article {pmid29573209, year = {2018}, author = {Huang, L and Xu, W and Su, Y and Zhao, L and Yan, Q}, title = {Regulatory role of the RstB-RstA system in adhesion, biofilm production, motility, and hemolysis.}, journal = {MicrobiologyOpen}, volume = {7}, number = {5}, pages = {e00599}, pmid = {29573209}, issn = {2045-8827}, mesh = {*Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Gene Silencing ; *Hemolysis ; Hydrogen-Ion Concentration ; *Locomotion ; Temperature ; Vibrio alginolyticus/drug effects/genetics/*physiology/radiation effects ; Virulence ; }, abstract = {For infection, initial invasion of the host is of great importance, with adhesion playing a critical role. We previously demonstrated rstA and rstB are remarkably downregulated in Vibrio alginolyticus cultured under heavy metal and acidic stresses, with impaired adhesion, suggesting that rstA and rstB might be involved in adhesion regulation. The present study showed that rstA and rstB silencing resulted in impaired adhesion, biofilm production, motility, hemolysis, and virulence. Meanwhile, changes of temperature, starvation, and pH remarkably affected rstA and rstB expression. These findings indicated that (1) rstA and rstB are critical regulators of adhesion in V. alginolyticus; (2) rstA and rstB have remarkable effects on biofilm production, motility, hemolysis, and virulence in V. alginolyticus; (3) rstA and rstB modulate adhesion in response to environmental changes of temperature, pH, and starvation.}, } @article {pmid29572816, year = {2018}, author = {Andersen, KK and Vad, BS and Kjaer, L and Tolker-Nielsen, T and Christiansen, G and Otzen, DE}, title = {Pseudomonas aeruginosa rhamnolipid induces fibrillation of human α-synuclein and modulates its effect on biofilm formation.}, journal = {FEBS letters}, volume = {592}, number = {9}, pages = {1484-1496}, doi = {10.1002/1873-3468.13038}, pmid = {29572816}, issn = {1873-3468}, mesh = {Biofilms/drug effects/*growth & development ; Glycolipids/*pharmacology ; Humans ; Kinetics ; Micelles ; Permeability/drug effects ; Protein Aggregates/*drug effects ; Protein Conformation, beta-Strand/drug effects ; Pseudomonas aeruginosa/drug effects/*physiology ; alpha-Synuclein/*chemistry/metabolism/pharmacology ; }, abstract = {The Parkinson's disease-associated protein α-synuclein (αSN) is natively unfolded but its structure can be modulated by membranes and surfactants. The opportunistic pathogen Pseudomonas aeruginosa (PA) produces and secretes the biosurfactant rhamnolipid (RL) which modulates bacterial biofilm. Here, we show that monomeric RL enhances the ability of αSN to permeabilize membranes, while micellar RL rapidly induces protein β-sheet structure with a worm-like fibrillary appearance, which cannot seed RL-free fibrillation but transforms into linear fibrils faster than αSN fibrillating on its own. Exposure to αSN reduces the degree of biofilm formation by PA unless RL is present. Our data suggest that RL interactions with αSN may affect both αSN aggregation and cell toxicity, potentially implicating microbiomic metabolites in the origin and propagation of Parkinson's disease.}, } @article {pmid29572150, year = {2018}, author = {Khezri, A and Karimi, A and Yazdian, F and Jokar, M and Mofradnia, SR and Rashedi, H and Tavakoli, Z}, title = {Molecular dynamic of curcumin/chitosan interaction using a computational molecular approach: Emphasis on biofilm reduction.}, journal = {International journal of biological macromolecules}, volume = {114}, number = {}, pages = {972-978}, doi = {10.1016/j.ijbiomac.2018.03.100}, pmid = {29572150}, issn = {1879-0003}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*growth & development ; *Chitosan/chemistry/pharmacology ; *Curcumin/chemistry/pharmacology ; *Models, Biological ; *Molecular Dynamics Simulation ; Streptococcus mutans/*physiology ; }, abstract = {Nanotechnology-based drug delivery systems have been used to enhance bioavailability and biological activities. Chitosan incorporating curcumin can serve as a biocompatible substitute for metallic nanoparticles in preventing biofilm formation of Streptococcus mutans and plaque on teeth. The interactions between chitosan nanoparticle as a carrier and curcumin, a natural antibacterial agent, were simulated. The binding conformation between curcumin-chitosan was obtained using the Lamarckian Genetic Algorithm in Autodock™ software in chitosan nanoparticle. The interaction stability was examined in the molecular dynamic stages, with isothermal-isobaric ensemble in the CHARMM Force Field. The results showed the root mean square deviation (RMSD) and the root mean square fluctuations (RMSF) for all complex's atoms were relaxed after 4ns (RMSD for the all-atoms was 26.81±0.1 (Å); RMSF 1.13±0.02Å). For each section, the estimation of RMSD, RMSF, radius of gyration, inter-H bond and other analysis confirmed that, during the first interval;10ns, there was a stable binding between the two sections. Although all bindings disappeared from 10 to 20ns, the curcumin was trapped inside the chitosan nanoparticles, and no release took place until 20ns, after which the curcumin began to release. This trend suggests that chitosan nanoparticle has ability to carry the curcumin.}, } @article {pmid29571979, year = {2018}, author = {Farisa Banu, S and Rubini, D and Shanmugavelan, P and Murugan, R and Gowrishankar, S and Karutha Pandian, S and Nithyanand, P}, title = {Effects of patchouli and cinnamon essential oils on biofilm and hyphae formation by Candida species.}, journal = {Journal de mycologie medicale}, volume = {28}, number = {2}, pages = {332-339}, doi = {10.1016/j.mycmed.2018.02.012}, pmid = {29571979}, issn = {1773-0449}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/pathogenicity/ultrastructure ; Candida albicans/drug effects ; Candidiasis/microbiology ; Cinnamomum zeylanicum/*chemistry ; Humans ; Hyphae/drug effects/ultrastructure ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Oils, Volatile/*pharmacology ; Pogostemon/*chemistry ; Virulence ; }, abstract = {The prevalence and fatality rates with biofilm-associated candidal infections have remained a challenge to the medical fraternity despite major advances in the field of antifungal therapy. Traditionally, essential oils (EOs) from the aromatic plants have been found to be excellent therapeutic agents to treat fungal ailments. The present study explores the antivirulent and antibiofilm effects of under explored leaf EOs of Indian patchouli EO extracted from Pogostemon heyneanus (PH), Indian cassia from Cinnamomum tamala (CT) and camphor EO from C. camphora (CC) against Candida species. The EOs were investigated for its efficacy to disrupt the young and preformed Candida spp. biofilms and to inhibit the yeast to hyphal transition, a hallmark virulent trait of C. albicans. The ability of these EOs to inhibit metabolically active cells was assessed through XTT assay. Of these three EOs, CT EO showed enhanced biofilm inhibition than others and hence it was further selected to study its biomass inhibition potential and exopolysaccharide layer disruption ability. The CT EO reduced the biomass of the preformed biofilms of all three Candida strains, which was supported by confocal microscopy. It also disrupted the exopolysaccharide layer of the Candida strains as shown by scanning electron microscopy. The present findings validate the effectiveness of EOs against the virulence of Candida spp. and emphasize the pharmaceutical potential of several native but yet unexplored wild aromatic plants in the prospect of therapeutic application.}, } @article {pmid29571725, year = {2018}, author = {Pattnaik, SS and Ranganathan, S and Ampasala, DR and Syed, A and Ameen, F and Busi, S}, title = {Attenuation of quorum sensing regulated virulence and biofilm development in Pseudomonas aeruginosa PAO1 by Diaporthe phaseolorum SSP12.}, journal = {Microbial pathogenesis}, volume = {118}, number = {}, pages = {177-189}, doi = {10.1016/j.micpath.2018.03.031}, pmid = {29571725}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/isolation & purification/*metabolism/*pharmacology ; Ascomycota/*chemistry/*metabolism ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Chitinases/metabolism ; Glycolipids/metabolism ; Hydrophobic and Hydrophilic Interactions ; Ligases/metabolism ; Metalloendopeptidases/metabolism ; Metalloproteases ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Polysaccharides, Bacterial/metabolism ; Pseudomonas aeruginosa/*drug effects/*metabolism ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects/physiology ; Trans-Activators/metabolism ; Transcription Factors/metabolism ; Virulence/drug effects ; Virulence Factors/metabolism ; }, abstract = {In recent years, Pseudomonas aeruginosa PAO1 emerged as the significant pathogenic microorganism in majority of the hospital-acquired infections due to its resistance to the conventional antibiotics by virtue of its highly organized quorum sensing and associated biofilm formation. In the present study, quorum sensing attenuation potential of Diaporthe phaseolorum SSP12 extract was investigated against P. aeruginosa PAO1 amply supported by molecular docking studies. D. phaseolorum SSP12 extract significantly inhibited the production of LasI/R mediated LasA protease, LasB elastase and chitinase with 66.52 ± 5.41, 71.26 ± 4.58 and 61.16 ± 4.28% of inhibition respectively at a concentration of 750 μg mL[-1]. In addition, RhlI/R mediated production of pyocyanin, exopolysaccharides and rhamnolipids were also down-regulated by 74.71 ± 3.97, 66.41 ± 3.62 and 63.75 ± 3.76% respectively on treatment with sub-MIC concentration of D. phaseolorum SSP12. The light, fluorescence and confocal laser scanning microscopic (CLSM) analysis confirmed the significant disruption in biofilm formation. The presence of bioactive constituents such as phenyl ethylalcohol, 2, 4-di-tert-butylphenol, fenaclon, 1, 4-phenylenediacetic acid, and benzyl hydrazine in D. phaseolorum SSP12 extract was evident from Gas chromatography-mass spectrophotometric (GC-MS) analysis. From the in silico molecular docking studies, fenaclon and 2, 4-di-tert-butylphenol competitively binds to QS receptors LasR and RhlR and alters the binding of its cognate ligands and modulates the expression of virulence phenotypes. The promising anti quorum sensing efficacy of D. phaseolorum SSP12 extract suggested new avenues for development of anti-infective drugs from fungal derived metabolites to counteract the problems associated with conventional antibiotic therapies.}, } @article {pmid29571086, year = {2018}, author = {Chan, S and Pullerits, K and Riechelmann, J and Persson, KM and Rådström, P and Paul, CJ}, title = {Monitoring biofilm function in new and matured full-scale slow sand filters using flow cytometric histogram image comparison (CHIC).}, journal = {Water research}, volume = {138}, number = {}, pages = {27-36}, doi = {10.1016/j.watres.2018.03.032}, pmid = {29571086}, issn = {1879-2448}, mesh = {Bacteria/isolation & purification ; Bacterial Load ; Bacterial Physiological Phenomena ; *Biofilms ; Filtration/*instrumentation/methods ; Flow Cytometry ; Silicon Dioxide/chemistry ; Water Purification/*instrumentation/methods ; }, abstract = {While slow sand filters (SSFs) have produced drinking water for more than a hundred years, understanding of their associated microbial communities is limited. In this study, bacteria in influent and effluent water from full-scale SSFs were explored using flow cytometry (FCM) with cytometric histogram image comparison (CHIC) analysis; and routine microbial counts for heterotrophs, total coliforms and Escherichia coli. To assess if FCM can monitor biofilm function, SSFs differing in age and sand composition were compared. FCM profiles from two established filters were indistinguishable. To examine biofilm in the deep sand bed, SSFs were monitored during a scraping event, when the top layer of sand and the schmutzdecke are removed to restore flow through the filter. The performance of an established SSF was stable: total organic carbon (TOC), pH, numbers of heterotrophs, coliforms, E. coli, and FCM bacterial profile were unaffected by scraping. However, the performance of two newly-built SSFs containing new and mixed sand was compromised: breakthrough of both microbial indicators and TOC occurred following scraping. The compromised performance of the new SSFs was reflected in distinct effluent bacterial communities; and, the presence of microbial indicators correlated to influent bacterial communities. This demonstrated that FCM can monitor SSF performance. Removal of the top layer of sand did not alter the effluent water from the established SSF, but did affect that of the SSFs containing new sand. This suggests that the impact of the surface biofilm on effluent water is greater when the deep sand bed biofilm is not established.}, } @article {pmid29571052, year = {2018}, author = {Asker, D and Awad, TS and Baker, P and Howell, PL and Hatton, BD}, title = {Non-eluting, surface-bound enzymes disrupt surface attachment of bacteria by continuous biofilm polysaccharide degradation.}, journal = {Biomaterials}, volume = {167}, number = {}, pages = {168-176}, doi = {10.1016/j.biomaterials.2018.03.016}, pmid = {29571052}, issn = {1878-5905}, mesh = {Bacterial Adhesion/drug effects ; Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Enzymes, Immobilized/chemistry/*pharmacology ; Glycoside Hydrolases/chemistry/*pharmacology ; Humans ; Models, Molecular ; Polysaccharides, Bacterial/*metabolism ; Pseudomonas Infections/microbiology/prevention & control ; Pseudomonas aeruginosa/*drug effects/physiology ; Surface Properties ; }, abstract = {Bacterial colonization and biofilm formation on surfaces are typically mediated by the deposition of exopolysaccharides and conditioning protein layers. Pseudomonas aeruginosa is a nosocomial opportunistic pathogen that utilizes strain-specific exopolysaccharides such as Psl, Pel or alginate for both initial surface attachment and biofilm formation. To generate surfaces that resist P. aeruginosa colonization, we covalently bound a Psl-specific glycoside hydrolase (PslGh) to several, chemically-distinct surfaces using amine functionalization (APTMS) and glutaraldehyde (GDA) linking. In situ quartz crystal microbalance (QCM) experiments and fluorescence microscopy demonstrated a complete lack of Psl adsorption on the PslGh-bound surfaces. Covalently-bound PslGh was also found to significantly reduce P. aeruginosa surface attachment and biofilm formation over extended growth periods (8 days). The PslGh surfaces showed a ∼99.9% (∼3-log) reduction in surface associated bacteria compared to control (untreated) surfaces, or those treated with inactive enzyme. This work demonstrates a non-eluting 'bioactive' surface that specifically targets a mechanism of cell adhesion, and that surface-bound glycoside hydrolase can significantly reduce surface colonization of bacteria through local, continuous enzymatic degradation of exopolysaccharide (Psl). These results have significant implications for the surface design of medical devices to keep bacteria in a planktonic state, and therefore susceptible to antibiotics and antimicrobials.}, } @article {pmid29570813, year = {2018}, author = {Cantone, E and Negri, R and Roscetto, E and Grassia, R and Catania, MR and Capasso, P and Maffei, M and Soriano, AA and Leone, CA and Iengo, M and Greco, L}, title = {In Vivo Biofilm Formation, Gram-Negative Infections and TAS2R38 Polymorphisms in CRSw NP Patients.}, journal = {The Laryngoscope}, volume = {128}, number = {10}, pages = {E339-E345}, doi = {10.1002/lary.27175}, pmid = {29570813}, issn = {1531-4995}, mesh = {Adult ; Biofilms/growth & development ; Chronic Disease ; Cohort Studies ; Female ; Genetic Predisposition to Disease ; Genotype ; Gram-Negative Bacterial Infections/complications/*genetics ; Humans ; Italy ; Male ; Microscopy, Confocal ; Middle Aged ; Nasal Polyps/complications/*genetics ; Phenotype ; Polymorphism, Single Nucleotide ; Prospective Studies ; Receptors, G-Protein-Coupled/*genetics ; Rhinitis/complications/*genetics ; Sinusitis/complications/*genetics ; Taste/genetics ; }, abstract = {OBJECTIVES: Among the predisposing factors implicated in the immune response to airway bacterial infections, genetic variations of the bitter taste receptor TAS2R38, which is expressed in the cilia of the human sinonasal epithelial cells, seem to be associated with susceptibility to chronic rhinosinusitis (CRS) and in vitro biofilm formation. Polymorphisms in TAS2R38 generate two common haplotypes: the nonfunctional AVI (Alanine, Valine, Isoleucine) and the functional PAV (Proline, Alanine, Valine) alleles, with the latter protecting against gram-negative sinonasal infections. The aim of this study is to investigate for the first time the relevance of TAS2R38 genetic variants in the susceptibility to bacterial infections associated with in vivo biofilm formation in chronic rhinosinusitis with nasal polyps (CRSwNP) patients.

STUDY DESIGN: A prospective study on 100 adult patients undergoing functional endoscopic sinus surgery (FESS) for CRSwNP.

METHODS: Propylthiouracile (PROP) testing and TAS2R38 genotyping were applied to characterize patients for receptor functionality. Sinonasal mucosa samples were processed for microbiological examination and biofilm detection.

RESULTS: The nonfunctional genotype is more frequent among CRS patients than in the general population (25% vs. 18.4%, P = 0.034). Airway gram-negative infections are primarily associated with the AVI haplotype (88.9% vs. 11.1% PAV/PAV-functional genotype, P = 0.023). Biofilm formation is prevalent in CRS patients with the AVI nontaster phenotype (62.5% vs. 33.3% PAV taster or supertaster phenotype, P = 0.05).

CONCLUSION: Our findings confirm an inverse correlation between TAS2R38 functionality and gram-negative infections in Italian patients with CRSwNP. In addition, for the first time we demonstrated a relationship between in vivo microbial biofilm and TAS2R38 receptor variants.

LEVEL OF EVIDENCE: 2b. Laryngoscope, 128:E339-E345, 2018.}, } @article {pmid29570706, year = {2018}, author = {Michalik, M and Samet, A and Marszałek, A and Krawczyk, B and Kotłowski, R and Nowicki, A and Anyszek, T and Nowicki, S and Kur, J and Nowicki, B}, title = {Intra-operative biopsy in chronic sinusitis detects pathogenic Escherichia coli that carry fimG/H, fyuA and agn43 genes coding biofilm formation.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0192899}, pmid = {29570706}, issn = {1932-6203}, mesh = {Adhesins, Escherichia coli/*genetics ; Adult ; *Biofilms ; Biopsy ; Chronic Disease ; *Escherichia coli/isolation & purification/physiology ; Escherichia coli Infections/*genetics ; Escherichia coli Proteins/*genetics ; Female ; Fimbriae Proteins/*genetics ; Humans ; Male ; Middle Aged ; *Phylogeny ; Receptors, Cell Surface/*genetics ; Sinusitis/genetics/*microbiology/pathology ; }, abstract = {The aim of this study was to investigate whether or not surgical biopsy of sinus tissue in chronic sinusitis, not responsive to treatment, would detect E. coli. We intended to evaluate E. coli virulence genes, therefore dispute the causal role of such an unusual microorganism in chronic sinusitis, as well as consider effective pathogen-targeted therapy. Patients with E. coli isolated by intra-operative puncture biopsy were included in the study. Genetic analysis of E. coli isolates, including phylogenetic grouping and virulence factor characteristics, were done by multiplex PCR. We identified 26 patients with chronic sinusitis, in which 26 E. coli isolates were cultured. The E. coli isolates belonged mainly to pathogenic phylogenetic group B2, and carried multiple virulence genes. Three genes in particular were present in all (100%) of examined isolates, they were (1) marker agn43 gene for forming biofilm, (2) type 1 fimbriae (fimG/H gene) and (3) yersiniabactin receptor (fyuA). Furthermore, a pseudo-phylogenetic tree of virulence genes distribution revealed possible cooperation between agn43, fimG/H, and fyuA in the coding of biofilm formation. Intra-operative-biopsy and culture-based therapy, targeting the isolated E. coli, coincided with long-term resolution of symptoms. This is the first report demonstrating an association between a highly pathogenic E. coli, chronic sinus infection, and resolution of symptoms upon E. coli targeted therapy, a significant finding due to the fact that E. coli has not been considered to be a commensal organism of the oropharynx or sinuses. We postulate that the simultaneous presence of three genes, each coding biofilm formation, may in part account for the chronicity of E. coli sinusitis.}, } @article {pmid29568284, year = {2018}, author = {Tejedor-Sanz, S and Fernández-Labrador, P and Hart, S and Torres, CI and Esteve-Núñez, A}, title = {Geobacter Dominates the Inner Layers of a Stratified Biofilm on a Fluidized Anode During Brewery Wastewater Treatment.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {378}, pmid = {29568284}, issn = {1664-302X}, abstract = {In this study, we designed a microbial electrochemical fluidized bed reactor (ME-FBR), with an electroconductive anodic bed made of activated carbon particles for treating a brewery wastewater. Under a batch operating mode, acetate and propionate consumption rates were 13-fold and 2.4-fold higher, respectively, when the fluidized anode was polarized (0.2 V) with respect to open circuit conditions. Operating in a continuous mode, this system could effectively treat the brewery effluent at organic loading rates (OLR) over 1.7 kg m[-3]NRV d[-1] and with removal efficiencies of 95 ± 1.4% (hydraulic retention time of 1 day and an influent of 1.7 g-COD L[-1]). The coulombic efficiency values highly depended upon the OLR applied, and varied from a 56 ± 15% to 10 ± 1%. Fluorescence in situ hybridization (FISH) analysis revealed a relative high abundance of Geobacter species (ca. 20%), and clearly showed a natural microbial stratification. Interestingly, the Geobacter cluster was highly enriched in the innermost layers of the biofilm (thickness of 10 μm), which were in contact with the electroconductive particles of bed, whereas the rest of bacteria were located in the outermost layers. To our knowledge, this is the first time that such a clear microbial stratification has been observed on an anode-respiring biofilm. Our results revealed the relevant role of Geobacter in switching between the electrode and other microbial communities performing metabolic reactions in the outermost environment of the biofilm.}, } @article {pmid29567501, year = {2018}, author = {Sarikhani, M and Kermanshahi, RK and Ghadam, P and Gharavi, S}, title = {The role of probiotic Lactobacillus acidophilus ATCC 4356 bacteriocin on effect of HBsu on planktonic cells and biofilm formation of Bacillus subtilis.}, journal = {International journal of biological macromolecules}, volume = {115}, number = {}, pages = {762-766}, doi = {10.1016/j.ijbiomac.2018.03.087}, pmid = {29567501}, issn = {1879-0003}, mesh = {Bacillus subtilis/drug effects/*physiology ; Bacteriocins/*pharmacology ; Biofilms/*drug effects/*growth & development ; Lactobacillus acidophilus/*chemistry/physiology ; Microbial Sensitivity Tests ; Nucleoproteins/*pharmacology ; Plankton/cytology/*drug effects ; Probiotics/pharmacology ; }, abstract = {UNLABELLED: Bacillus subtilis is a Gram positive, aerobic and motile bacterium. Biofilm formation is an important feature of this bacterium which confers resistance to antimicrobial agents. The use of new antimicrobial reagents which eliminate biofilms are important and necessary. In this study, the effect of secondary metabolites (bacteriocin) from Lactobacillus acidophilus ATCC 4356 on Bacillus subtilis BM19 in the presence and absence of HBsu which is involved in the growth of planktonic cells and biofilm formation, is reported. HBsu nucleoprotein plays several roles in different processes of Bacillus subtilis cells such as replication, transcription, cell division, recombination and repair. In this study, for the first time, the effect of HBsu on biofilm formation is presented.

RESULTS: In the absence of HBsu, purified bacteriocin from L. acidophilus ATCC 4356 was more effective in inhibiting growth of B. subtilis BM19 planktonic cells as well as biofilm formation. The presence of HBsu on the other hand led to increased biofilm formation.}, } @article {pmid29566229, year = {2018}, author = {Mallik, D and Pal, S and Ghosh, AS}, title = {Involvement of AmpG in mediating a dynamic relationship between serine beta-lactamase induction and biofilm-forming ability of Escherichia coli.}, journal = {FEMS microbiology letters}, volume = {365}, number = {8}, pages = {}, doi = {10.1093/femsle/fny065}, pmid = {29566229}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/*metabolism ; *Biofilms/drug effects ; Escherichia coli/drug effects/genetics/*physiology ; Membrane Transport Proteins/genetics/*metabolism ; Microbial Sensitivity Tests ; Serine/genetics/metabolism ; beta-Lactamases/genetics/*metabolism ; beta-Lactams/pharmacology ; }, abstract = {AmpG permease is implicated both in beta-lactamase induction and peptidoglycan recycling in enterobacterial isolates. Here, physiological studies using molecular genetics show that deletion of AmpG permease dramatically increases beta-lactam susceptibility even in the presence of AmpC, TEM-1 and OXA beta-lactamases. Also, there is an appreciable decrease in the biofilm-forming ability of strains lacking this protein. Expression of this permease in excess probably compromises the integrity of the bacterial cells, leading to cell lysis. Based on these results, we propose that AmpG permease may be used as a potential antibiotic target and its suppression could efficiently inhibit both beta-lactamase induction and biofilm formation.}, } @article {pmid29563932, year = {2017}, author = {Majidpour, A and Fathizadeh, S and Afshar, M and Rahbar, M and Boustanshenas, M and Heidarzadeh, M and Arbabi, L and Soleymanzadeh Moghadam, S}, title = {Dose-Dependent Effects of Common Antibiotics Used to Treat Staphylococcus aureus on Biofilm Formation.}, journal = {Iranian journal of pathology}, volume = {12}, number = {4}, pages = {362-370}, pmid = {29563932}, issn = {1735-5303}, abstract = {BACKGROUND & OBJECTIVE: Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), represent serious nosocomial and community infections. Biofilm formation as an important virulence factor may be affected by sub-inhibitory levels of antibiotics. Few studies examined the effects of all therapeutic antimicrobial agents on clinical S.aureus. The current study aimed at observing the inducing and reducing effects of antibiotics, commonly used to treat staphylococcal infections on the production of staphylococcal biofilm.

METHODS: Four MRSA (1ATCC and 3 clinical) and 1 methicillin-susceptible Staphylococcus aureus (MSSA) strains with biofilm forming ability, evaluated by the Congo red agar (CRA) plate test, were employed. Biofilm formation was measured by crystal violet microtiter plate assay. Cefazolin, rifampicin, vancomycin, oxacillin, clindamycin, cotrimoxazole, minocycline, linezolid, azithromycin, and clarithromycin were added to wells ranging from 0.06to 128 µg/mL (1× to 1/1024 MIC dependent on the MIC value of each strain).

RESULTS: The current study showed that azithromycin and vancomycin had a significant inducing effect on biofilm formation. In contrast, linezolid, cefazolin, and clarithromycin, and in the second place, clindamycin and minocycline could inhibit the level of biofilm production in the sub-minimal inhibitory concentrations.

CONCLUSION: The findings demonstrated that the biofilm formation as an important virulence factor may be affected by the subinhibitory levels of antibiotics.}, } @article {pmid29563815, year = {2018}, author = {Zhao, JL and Liu, W and Xie, WY and Cao, XD and Yuan, L}, title = {Viability, biofilm formation, and MazEF expression in drug-sensitive and drug-resistant Mycobacterium tuberculosis strains circulating in Xinjiang, China.}, journal = {Infection and drug resistance}, volume = {11}, number = {}, pages = {345-358}, pmid = {29563815}, issn = {1178-6973}, abstract = {BACKGROUND: Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is one of the most common chronic infectious amphixenotic diseases worldwide. Prevention and control of TB are greatly difficult, due to the increase in drug-resistant TB, particularly multidrug-resistant TB. We speculated that there were some differences between drug-sensitive and drug-resistant MTB strains and that mazEF3,6,9 toxin-antitoxin systems (TASs) were involved in MTB viability. This study aimed to investigate differences in viability, biofilm formation, and MazEF expression between drug-sensitive and drug-resistant MTB strains circulating in Xinjiang, China, and whether mazEF3,6,9 TASs contribute to MTB viability under stress conditions.

MATERIALS AND METHODS: Growth profiles and biofilm-formation abilities of drug-sensitive, drug-resistant MTB strains and the control strain H37Rv were monitored. Using molecular biology experiments, the mRNA expression of the mazF3, 6, and 9 toxin genes, the mazE3, 6, and 9 antitoxin genes, and expression of the MazF9 protein were detected in the different MTB strains, H37RvΔmazEF3,6,9 mutants from the H37Rv parent strain were generated, and mutant viability was tested.

RESULTS: Ex vivo culture analyses demonstrated that drug-resistant MTB strains exhibit higher survival rates than drug-sensitive strains and the control strain H37Rv. However, there was no statistical difference in biofilm-formation ability in the drug-sensitive, drug-resistant, and H37Rv strains. mazE3,6 mRNA-expression levels were relatively reduced in the drug-sensitive and drug-resistant strains compared to H37Rv. Conversely, mazE3,9 expression was increased in drug-sensitive strains compared to drug-resistant strains. Furthermore, compared with the H37Rv strain, mazF3,6 expression was increased in drug-resistant strains, mazF9 expression was increased in drug-sensitive strains, and mazF9 exhibited reduced expression in drug-resistant strains compared with drug-sensitive strains. Protein expression of mazF9 was increased in drug-sensitive and drug-resistant strains compared to H37Rv, while drug-resistant strains exhibited reduced mazF9 expression compared to drug-sensitive strains. Compared to H37Rv, H37RvΔmazEF3,6,9-deletion mutants grew more slowly under both stress conditions, and their ability to survive in host macrophages was also weaker. Furthermore, the host macrophage-apoptosis rate was higher after infection with any of the H37RvΔmazEF3,6,9 mutants than with the H37Rv strain.

CONCLUSION: The increased viability of MTB drug-resistant strains compared with drug-sensitive strains is likely to be related to differential MazEF mRNA and protein expression. mazEF3,6,9 TASs contribute to MTB viability under stress conditions.}, } @article {pmid29563542, year = {2018}, author = {Fang, K and Jin, X and Hong, SH}, title = {Probiotic Escherichia coli inhibits biofilm formation of pathogenic E. coli via extracellular activity of DegP.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {4939}, pmid = {29563542}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Enterohemorrhagic Escherichia coli/*physiology ; Heat-Shock Proteins/*metabolism ; Periplasmic Proteins/*metabolism ; *Probiotics ; Pseudomonas aeruginosa/*physiology ; Serine Endopeptidases/*metabolism ; Staphylococcus aureus/*physiology ; }, abstract = {Many chronic infections involve bacterial biofilms, which are difficult to eliminate using conventional antibiotic treatments. Biofilm formation is a result of dynamic intra- or inter-species interactions. However, the nature of molecular interactions between bacteria in multi-species biofilms are not well understood compared to those in single-species biofilms. This study investigated the ability of probiotic Escherichia coli Nissle 1917 (EcN) to outcompete the biofilm formation of pathogens including enterohemorrhagic E. coli (EHEC), Pseudomonas aeruginosa, Staphylococcus aureus, and S. epidermidis. When dual-species biofilms were formed, EcN inhibited the EHEC biofilm population by 14-fold compared to EHEC single-species biofilms. This figure was 1,100-fold for S. aureus and 8,300-fold for S. epidermidis; however, EcN did not inhibit P. aeruginosa biofilms. In contrast, commensal E. coli did not exhibit any inhibitory effect toward other bacterial biofilms. We identified that EcN secretes DegP, a bifunctional (protease and chaperone) periplasmic protein, outside the cells and controls other biofilms. Although three E. coli strains tested in this study expressed degP, only the EcN strain secreted DegP outside the cells. The deletion of degP disabled the activity of EcN in inhibiting EHEC biofilms, and purified DegP directly repressed EHEC biofilm formation. Hence, probiotic E. coli outcompetes pathogenic biofilms via extracellular DegP activity during dual-species biofilm formation.}, } @article {pmid29563427, year = {2017}, author = {Yu, OY and Zhao, IS and Mei, ML and Lo, EC and Chu, CH}, title = {Dental Biofilm and Laboratory Microbial Culture Models for Cariology Research.}, journal = {Dentistry journal}, volume = {5}, number = {2}, pages = {}, pmid = {29563427}, issn = {2304-6767}, abstract = {Dental caries form through a complex interaction over time among dental plaque, fermentable carbohydrate, and host factors (including teeth and saliva). As a key factor, dental plaque or biofilm substantially influence the characteristic of the carious lesions. Laboratory microbial culture models are often used because they provide a controllable and constant environment for cariology research. Moreover, they do not have ethical problems associated with clinical studies. The design of the microbial culture model varies from simple to sophisticated according to the purpose of the investigation. Each model is a compromise between the reality of the oral cavity and the simplification of the model. Researchers, however, can still obtain meaningful and useful results from the models they select. Laboratory microbial culture models can be categorized into a closed system and an open system. Models in the closed system have a finite supply of nutrients, and are also simple and cost-effective. Models in the open system enabled the supply of a fresh culture medium and the removal of metabolites and spent culture liquid simultaneously. They provide better regulation of the biofilm growth rate than the models in the closed system. This review paper gives an overview of the dental plaque biofilm and laboratory microbial culture models used for cariology research.}, } @article {pmid29562719, year = {2018}, author = {Sharma, K and Pagedar Singh, A}, title = {Antibiofilm Effect of DNase against Single and Mixed Species Biofilm.}, journal = {Foods (Basel, Switzerland)}, volume = {7}, number = {3}, pages = {}, pmid = {29562719}, issn = {2304-8158}, abstract = {Biofilms are aggregates of microorganisms that coexist in socially coordinated micro-niche in a self-produced polymeric matrix on pre-conditioned surfaces. The biofilm matrix reduces the efficacy of antibiofilm strategies. DNase degrades the extracellular DNA (e-DNA) present in the matrix, rendering the matrix weak and susceptible to antimicrobials. In the current study, the effect of DNase I was evaluated during biofilm formation (pre-treatment), on preformed biofilms (post-treatment) and both (dual treatment). The DNase I pre-treatment was optimized for P. aeruginosa PAO1 (model biofilm organism) at 10 µg/mL and post-treatment at 10 µg/mL with 15 min of contact duration. Inclusion of Mg[2+] alongside DNase I post-treatment resulted in 90% reduction in biofilm within only 5 min of contact time (irrespective of age of biofilm). On extension of these findings, DNase I was found to be less effective against mixed species biofilm than individual biofilms. DNase I can be used as potent antibiofilm agent and with further optimization can be effectively used for biofilm prevention and reduction in situ.}, } @article {pmid29560500, year = {2019}, author = {Laube, N and Bernsmann, F and Fisang, C}, title = {[Individualized patient care with urological implants using biofilm-resistant surface concepts].}, journal = {Der Urologe. Ausg. A}, volume = {58}, number = {2}, pages = {143-150}, pmid = {29560500}, issn = {1433-0563}, mesh = {Bacteria ; *Biofilms ; Humans ; Patient Care ; *Stents/microbiology ; *Ureter/microbiology ; }, abstract = {Urological implants in the urinary tract are routinely used to ensure urine flow. However, the morbidities are numerous concerning long-term derivations. Especially with the ureteral stents, failure can have considerable consequences. Since the surfaces of all urological implants are more or less ideal substrates for microorganisms, the formation of bacterial biofilms is a regularly observed and often serious complication, which in many cases forces early implant replacement. The burden on the patient and the health system are enormous. This article provides an overview of the numerous strategies developed or under development to protect against bacterial adhesion. Observations in use show "sometimes good, sometimes bad results" for all strategies, which may be due to the fact that the treated patients have different biological and clinical conditions. The implants are each equipped with defense mechanisms designed for certain "scenarios"; if they are used inadequately in this respect, they cannot optimally fulfill their task. Systematic observations of the "outcomes" and evaluation of the obtained data would be necessary in order to be able to assign an "optimal" effect spectrum to each defense strategy, thus, ultimately prospectively giving patients the most suitable product in advance. Systematic use of the existing implant concepts can avoid a large number of implant-related complications "ad hoc"; further development steps with regard to improved surface modifications can be made more specifically. However, the hope of a "super strategy" is likely to remain unfulfilled because bacteria as "opponents" have already proved billions of years of survival.}, } @article {pmid29559963, year = {2018}, author = {Keijser, BJF and van den Broek, TJ and Slot, DE and van Twillert, L and Kool, J and Thabuis, C and Ossendrijver, M and van der Weijden, FA and Montijn, RC}, title = {The Impact of Maltitol-Sweetened Chewing Gum on the Dental Plaque Biofilm Microbiota Composition.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {381}, pmid = {29559963}, issn = {1664-302X}, abstract = {Background: The oral cavity harbors a complex microbial ecosystem, intimately related to oral health and disease. The use of polyol-sweetened gum is believed to benefit oral health through stimulation of salivary flow and impacting oral pathogenic bacteria. Maltitol is often used as sweetener in food products. This study aimed to establish the in vivo effects of frequent consumption of maltitol-sweetened chewing gum on the dental plaque microbiota in healthy volunteers and to establish the cellular and molecular effects by in vitro cultivation and transcriptional analysis. Results: An intervention study was performed in 153 volunteers, randomly assigned to three groups (www.trialregister.nl; NTR4165). One group was requested to use maltitol gum five times daily, one group used gum-base, and the third group did not use chewing gum. At day 0 and day 28, 24 h-accumulated supragingival plaque was collected at the lingual sites of the lower jaw and the buccal sites of the upper jaw and analyzed by 16S ribosomal rRNA gene sequencing. At day 42, 2 weeks after completion of the study, lower-jaw samples were collected and analyzed. The upper buccal plaque microbiota composition had lower bacterial levels and higher relative abundances of (facultative) aerobic species compared to the lower lingual sites. There was no difference in bacterial community structure between any of the three study groups (PERMANOVA). Significant lower abundance of several bacterial phylotypes was found in maltitol gum group compared to the gum-base group, including Actinomyces massiliensis HOT 852 and Lautropia mirabilis HOT 022. Cultivation studies confirmed growth inhibition of A. massiliensis and A. johnsonii by maltitol at levels of 1% and higher. Transcriptome analysis of A. massiliensis revealed that exposure to maltitol resulted in changes in the expression of genes linked to osmoregulation, biofilm formation, and central carbon metabolism. Conclusion: The results showed that chewing itself only marginally impacted the plaque microbiota composition. Use of maltitol-sweetened gum lowered abundance of several bacterial species. Importantly, the species impacted play a key role in the early formation of dental biofilms. Further studies are required to establish if frequent use of maltitol gum impacts early dental-plaque biofilm development.}, } @article {pmid29559526, year = {2018}, author = {Lee, CK and de Anda, J and Baker, AE and Bennett, RR and Luo, Y and Lee, EY and Keefe, JA and Helali, JS and Ma, J and Zhao, K and Golestanian, R and O'Toole, GA and Wong, GCL}, title = {Multigenerational memory and adaptive adhesion in early bacterial biofilm communities.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {17}, pages = {4471-4476}, pmid = {29559526}, issn = {1091-6490}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; U54 CA193417/CA/NCI NIH HHS/United States ; R01 AI102584/AI/NIAID NIH HHS/United States ; R01 AI143730/AI/NIAID NIH HHS/United States ; T32 GM008185/GM/NIGMS NIH HHS/United States ; T32 AR071307/AR/NIAMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Cyclic AMP/*metabolism ; Fimbriae, Bacterial/*physiology ; Pseudomonas aeruginosa/*physiology ; Second Messenger Systems/*physiology ; }, abstract = {Using multigenerational, single-cell tracking we explore the earliest events of biofilm formation by Pseudomonas aeruginosa During initial stages of surface engagement (≤20 h), the surface cell population of this microbe comprises overwhelmingly cells that attach poorly (∼95% stay <30 s, well below the ∼1-h division time) with little increase in surface population. If we harvest cells previously exposed to a surface and direct them to a virgin surface, we find that these surface-exposed cells and their descendants attach strongly and then rapidly increase the surface cell population. This "adaptive," time-delayed adhesion requires determinants we showed previously are critical for surface sensing: type IV pili (TFP) and cAMP signaling via the Pil-Chp-TFP system. We show that these surface-adapted cells exhibit damped, coupled out-of-phase oscillations of intracellular cAMP levels and associated TFP activity that persist for multiple generations, whereas surface-naïve cells show uncorrelated cAMP and TFP activity. These correlated cAMP-TFP oscillations, which effectively impart intergenerational memory to cells in a lineage, can be understood in terms of a Turing stochastic model based on the Pil-Chp-TFP framework. Importantly, these cAMP-TFP oscillations create a state characterized by a suppression of TFP motility coordinated across entire lineages and lead to a drastic increase in the number of surface-associated cells with near-zero translational motion. The appearance of this surface-adapted state, which can serve to define the historical classification of "irreversibly attached" cells, correlates with family tree architectures that facilitate exponential increases in surface cell populations necessary for biofilm formation.}, } @article {pmid29558680, year = {2018}, author = {Crespo Tapia, N and den Besten, HMW and Abee, T}, title = {Glycerol metabolism induces Listeria monocytogenes biofilm formation at the air-liquid interface.}, journal = {International journal of food microbiology}, volume = {273}, number = {}, pages = {20-27}, doi = {10.1016/j.ijfoodmicro.2018.03.009}, pmid = {29558680}, issn = {1879-3460}, mesh = {Bacterial Outer Membrane Proteins/biosynthesis/genetics ; Biofilms/*growth & development ; Chemotaxis/physiology ; Food Contamination/analysis ; Food Handling ; Food Microbiology ; Food Safety ; Glycerol/*metabolism ; Glycerol Kinase/biosynthesis/genetics ; Glycerol-3-Phosphate Dehydrogenase (NAD+)/biosynthesis/genetics ; Listeria monocytogenes/*growth & development/*metabolism ; Oxygen/*metabolism ; Plankton/microbiology ; }, abstract = {Listeria monocytogenes is a food-borne pathogen that can grow as a biofilm on surfaces. Biofilm formation in food-processing environments is a big concern for food safety, as it can cause product contamination through the food-processing line. Although motile aerobic bacteria have been described to form biofilms at the air-liquid interface of cell cultures, to our knowledge, this type of biofilm has not been described in L. monocytogenes before. In this study we report L. monocytogenes biofilm formation at the air-liquid interface of aerobically grown cultures, and that this phenotype is specifically induced when the media is supplemented with glycerol as a carbon and energy source. Planktonic growth, metabolic activity assays and HPLC measurements of glycerol consumption over time showed that glycerol utilization in L. monocytogenes is restricted to growth under aerobic conditions. Gene expression analysis showed that genes encoding the glycerol transporter GlpF, the glycerol kinase GlpK and the glycerol 3-phosphate dehydrogenase GlpD were upregulated in the presence of oxygen, and downregulated in absence of oxygen. Additionally, motility assays revealed the induction of aerotaxis in the presence of glycerol. Our results demonstrate that the formation of biofilms at the air-liquid interface is dependent on glycerol-induced aerotaxis towards the surface of the culture, where L. monocytogenes has access to higher concentrations of oxygen, and is therefore able to utilize this compound as a carbon source.}, } @article {pmid29558522, year = {2018}, author = {Christensen, GA and Moon, J and Veach, AM and Mosher, JJ and Wymore, AM and van Nostrand, JD and Zhou, J and Hazen, TC and Arkin, AP and Elias, DA}, title = {Use of in-field bioreactors demonstrate groundwater filtration influences planktonic bacterial community assembly, but not biofilm composition.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0194663}, pmid = {29558522}, issn = {1932-6203}, mesh = {Bacteria/cytology/genetics/growth & development ; *Biofilms/growth & development ; Bioreactors/*microbiology ; Biota ; Environmental Restoration and Remediation/methods ; Filtration/*instrumentation/methods ; Groundwater/*microbiology ; Microbiota/physiology ; Plankton/growth & development/*physiology ; RNA, Ribosomal, 16S/genetics ; *Water Microbiology ; Water Purification/*instrumentation/methods ; Water Quality ; }, abstract = {Using in-field bioreactors, we investigated the influence of exogenous microorganisms in groundwater planktonic and biofilm microbial communities as part of the Integrated Field Research Challenge (IFRC). After an acclimation period with source groundwater, bioreactors received either filtered (0.22 μM filter) or unfiltered well groundwater in triplicate and communities were tracked routinely for 23 days after filtration was initiated. To address geochemical influences, the planktonic phase was assayed periodically for protein, organic acids, physico-/geochemical measurements and bacterial community (via 16S rRNA gene sequencing), while biofilms (i.e. microbial growth on sediment coupons) were targeted for bacterial community composition at the completion of the experiment (23 d). Based on Bray-Curtis distance, planktonic bacterial community composition varied temporally and between treatments (filtered, unfiltered bioreactors). Notably, filtration led to an increase in the dominant genus, Zoogloea relative abundance over time within the planktonic community, while remaining relatively constant when unfiltered. At day 23, biofilm communities were more taxonomically and phylogenetically diverse and substantially different from planktonic bacterial communities; however, the biofilm bacterial communities were similar regardless of filtration. These results suggest that although planktonic communities were sensitive to groundwater filtration, bacterial biofilm communities were stable and resistant to filtration. Bioreactors are useful tools in addressing questions pertaining to microbial community assembly and succession. These data provide a first step in understanding how an extrinsic factor, such as a groundwater inoculation and flux of microbial colonizers, impact how microbial communities assemble in environmental systems.}, } @article {pmid29555843, year = {2018}, author = {Fontaine, BM and Martin, KS and Garcia-Rodriguez, JM and Jung, C and Briggs, L and Southwell, JE and Jia, X and Weinert, EE}, title = {RNase I regulates Escherichia coli 2',3'-cyclic nucleotide monophosphate levels and biofilm formation.}, journal = {The Biochemical journal}, volume = {475}, number = {8}, pages = {1491-1506}, pmid = {29555843}, issn = {1470-8728}, support = {R01 GM125842/GM/NIGMS NIH HHS/United States ; T34 GM008156/GM/NIGMS NIH HHS/United States ; UL1 TR000454/TR/NCATS NIH HHS/United States ; UL1 TR002378/TR/NCATS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Escherichia coli/genetics/growth & development/*metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Nucleotides, Cyclic/*metabolism ; RNA Stability ; RNA, Bacterial/genetics/*metabolism ; RNA, Messenger/genetics/*metabolism ; Ribonuclease, Pancreatic/*metabolism ; Signal Transduction ; }, abstract = {Regulation of nucleotide and nucleoside concentrations is critical for faithful DNA replication, transcription, and translation in all organisms, and has been linked to bacterial biofilm formation. Unusual 2',3'-cyclic nucleotide monophosphates (2',3'-cNMPs) recently were quantified in mammalian systems, and previous reports have linked these nucleotides to cellular stress and damage in eukaryotes, suggesting an intriguing connection with nucleotide/nucleoside pools and/or cyclic nucleotide signaling. This work reports the first quantification of 2',3'-cNMPs in Escherichia coli and demonstrates that 2',3'-cNMP levels in E. coli are generated specifically from RNase I-catalyzed RNA degradation, presumably as part of a previously unidentified nucleotide salvage pathway. Furthermore, RNase I and 2',3'-cNMP levels are demonstrated to play an important role in controlling biofilm formation. This work identifies a physiological role for cytoplasmic RNase I and constitutes the first progress toward elucidating the biological functions of bacterial 2',3'-cNMPs.}, } @article {pmid29555779, year = {2018}, author = {Jin, X and Riedel-Kruse, IH}, title = {Biofilm Lithography enables high-resolution cell patterning via optogenetic adhesin expression.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {14}, pages = {3698-3703}, pmid = {29555779}, issn = {1091-6490}, support = {R21 AI139941/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Escherichia coli/genetics/*metabolism/radiation effects ; Bacterial Adhesion/*physiology/radiation effects ; Biofilms/*growth & development/radiation effects ; Escherichia coli/*growth & development/radiation effects ; *Light ; Optogenetics/*methods ; }, abstract = {Bacterial biofilms represent a promising opportunity for engineering of microbial communities. However, our ability to control spatial structure in biofilms remains limited. Here we engineer Escherichia coli with a light-activated transcriptional promoter (pDawn) to optically regulate expression of an adhesin gene (Ag43). When illuminated with patterned blue light, long-term viable biofilms with spatial resolution down to 25 μm can be formed on a variety of substrates and inside enclosed culture chambers without the need for surface pretreatment. A biophysical model suggests that the patterning mechanism involves stimulation of transiently surface-adsorbed cells, lending evidence to a previously proposed role of adhesin expression during natural biofilm maturation. Overall, this tool-termed "Biofilm Lithography"-has distinct advantages over existing cell-depositing/patterning methods and provides the ability to grow structured biofilms, with applications toward an improved understanding of natural biofilm communities, as well as the engineering of living biomaterials and bottom-up approaches to microbial consortia design.}, } @article {pmid29555180, year = {2018}, author = {Rodríguez-Sevilla, G and García-Coca, M and Romera-García, D and Aguilera-Correa, JJ and Mahíllo-Fernández, I and Esteban, J and Pérez-Jorge, C}, title = {Non-Tuberculous Mycobacteria multispecies biofilms in cystic fibrosis: development of an in vitro Mycobacterium abscessus and Pseudomonas aeruginosa dual species biofilm model.}, journal = {International journal of medical microbiology : IJMM}, volume = {308}, number = {3}, pages = {413-423}, doi = {10.1016/j.ijmm.2018.03.003}, pmid = {29555180}, issn = {1618-0607}, mesh = {Anti-Bacterial Agents ; Biofilms/drug effects/*growth & development ; Clarithromycin/pharmacology ; Cystic Fibrosis/*microbiology ; Humans ; In Vitro Techniques ; Models, Biological ; Mycobacterium abscessus/growth & development/*physiology/ultrastructure ; Nontuberculous Mycobacteria/growth & development/*physiology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/growth & development/*physiology/ultrastructure ; }, abstract = {Lung disease in cystic fibrosis (CF) is characterized by the progressive colonization of the respiratory tract by different bacteria, which develop polymicrobial biofilms. In the past decades, there has been an increase in the number of CF patients infected with Non-Tuberculous Mycobacteria (NTM). Although Mycobacterium abscessus is the main NTM isolated globally, little is known about M. abscessus multispecies biofilm formation. In the present study we developed an in vitro model to study the phenotypic characteristics of biofilms formed by M. abscessus and Pseudomonas aeruginosa, a major pathogen in CF. For that purpose, dual species biofilms were grown on polycarbonate membranes with a fixed concentration of P. aeruginosa and different inoculums of M. abscessus. The biofilms were sampled at 24, 48, and 72 h and bacteria were quantified in specific media. The results revealed that the increasing initial concentration of M. abscessus in dual species biofilms had an effect on its population only at 24 and 48 h, whereas P. aeruginosa was not affected by the different concentrations used of M. abscessus. Time elapsed increased biofilm formation of both species, specially between 24 and 48 h. According to the results, the conditions to produce a mature dual species biofilm in which the relative species distribution remained stable were 72 h growth of the mixed microbial culture at a 1:1 ratio. A significant decrease in mycobacterial population in dual compared to single species biofilms was found, suggesting that P. aeruginosa has a negative influence on M. abscessus. Finally, in a proof of concept experiment, young and mature dual species biofilms were exposed to clarithromycin.}, } @article {pmid29554553, year = {2018}, author = {Kalantar, M and Mardanpour, MM and Yaghmaei, S}, title = {A novel model for predicting bioelectrochemical performance of microsized-MFCs by incorporating bacterial chemotaxis parameters and simulation of biofilm formation.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {122}, number = {}, pages = {51-60}, doi = {10.1016/j.bioelechem.2018.03.002}, pmid = {29554553}, issn = {1878-562X}, mesh = {Algorithms ; Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Biosensing Techniques ; *Chemotaxis ; Computer Simulation ; Models, Biological ; Pseudomonas aeruginosa/*physiology ; Shewanella/*physiology ; }, abstract = {Bacterial transport parameters play a fundamental role in microbial population dynamics, biofilm formation and bacteria dispersion. In this study, the novel model was extended based on the capability of microsized microbial fuel cells (MFCs) as amperometric biosensors to predict the cells' chemotactic and bioelectrochemical properties. The model prediction results coincide with the experimental data of Shewanella oneidensis and chemotaxis mutant of P. aeruginosa bdlA and pilT strains, indicating the complementary role of numerical predictions for bioscreening applications of microsized MFCs. Considering the general mechanisms for electron transfer, substrate biodegradation, microbial growth and bacterial dispersion are the main features of the presented model. In addition, the genetic algorithm method was implemented by minimizing the objective function to estimate chemotaxis properties of the different strains. Microsized MFC performance was assessed by analyzing the microbial activity in the biofilm and the anolyte.}, } @article {pmid29554119, year = {2018}, author = {Różalska, B and Sadowska, B and Budzyńska, A and Bernat, P and Różalska, S}, title = {Biogenic nanosilver synthesized in Metarhizium robertsii waste mycelium extract - As a modulator of Candida albicans morphogenesis, membrane lipidome and biofilm.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0194254}, pmid = {29554119}, issn = {1932-6203}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/*metabolism ; Epithelial Cells/drug effects ; Fibroblasts/drug effects ; Fluconazole/pharmacology ; Humans ; Membrane Lipids/*metabolism ; *Metal Nanoparticles/chemistry ; *Metarhizium/chemistry ; *Mycelium/chemistry ; *Silver/chemistry ; }, abstract = {Due to low efficacy of classic antimicrobial drugs, finding new active preparations attracts much attention. In this study an innovative, cost-effective and environmentally friendly method was applied to produce silver nanoparticles (AgNPs) using filamentous fungi Metarhizium robertsii biomass waste. It was shown that these NPs possess prominent antifungal effects against C. albicans, C. glabrata and C. parapsilosis reference strains. Further detailed studies were performed on C. albicans ATCC 90028. AgNPs kill curve (CFU method and esterase-mediated reduction of fluorescein diacetate); fractionally inhibitory concentration index (FICI) with fluconazole (FLC); effect on fungal cell membrane permeability (propidium iodide (PI) staining), membrane lipids profile (HPLC-MS), yeast morphotypes and intracellular reactive oxygen species level (H2DCFDA probe) were investigated. Anti-adhesive and anti-biofilm properties of AgNPs (alone and in combination with FLC) were also tested. Biosafety of AgNPs use was assessed in vitro in cytotoxicity tests against L929 fibroblasts, pulmonary epithelial A549 cell line, and red blood cells. Significant reduction in the viability of yeast cells treated with AgNPs was shown within 6 h. The proportion of C. albicans PI-positive cells increased in a dose and time-dependent manner. Changes in the qualitative and quantitative profile of cell membrane lipids, including significant decline in the quantity of most phospholipid species containing C18:2 and an increase in the amount of phospholipids containing C18:1 acyl species were observed after yeast exposure to AgNPs. CLSM images showed an enhancement in ROS intracellular accumulation in C. albicans treated with biogenic nanosilver. C. albicans transformation from yeast to hyphal forms was also reduced. AgNPs decreased adhesion of yeast to abiotic surfaces, as well as acted synergistically with FLC against sessile population. At fungicidal and fungistatic concentrations, they were non-toxic to mammalian cells. Obtained results confirm suitability of our "green synthesis" method to produce AgNPs with therapeutic potential against fungal infections.}, } @article {pmid29554105, year = {2018}, author = {Sato, Y and Unno, Y and Ubagai, T and Ono, Y}, title = {Sub-minimum inhibitory concentrations of colistin and polymyxin B promote Acinetobacter baumannii biofilm formation.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0194556}, pmid = {29554105}, issn = {1932-6203}, mesh = {Acinetobacter Infections/*drug therapy/microbiology ; Acinetobacter baumannii/drug effects/*physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Colistin/pharmacology ; Cross Infection/*drug therapy/microbiology ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Polymyxin B/pharmacology ; RNA, Messenger/metabolism ; }, abstract = {We investigated the numbers of planktonic and biofilm cells and the expression levels of genes encoding efflux pumps and biofilm-related proteins in 10 clinical isolates of multi-drug resistant Acinetobacter baumannii (MDRA) as well as in its standard strain ATCC 19606 in the presence of colistin (CST), polymyxin B (PMB), minomycin (MIN), and tigecycline (TGC) at their respective sub-MICs. The number of planktonic and biofilm cells of ATCC 19606 decreased in the presence of all aforementioned antibiotics in a dose-dependent manner. Cell number also decreased in two representative MDRA strains, R2 and R3, in the presence of MIN and TGC in a dose-dependent manner. In contrast, the number of biofilm cells in these two strains increased in the presence of CST, while they increased significantly in the presence of PMB in R2 only. Pearson correlation analysis revealed that the number of biofilm cells was positively and significantly correlated with the mRNA levels of genes encoding efflux pumps (adeB and adeG) and autoinducer synthase (abaI) in strain R2 and adeB, adeG, adeJ, poly-acetyl-glucosamine-porin (pgaA), and abaI in strain R3 in the presence of CST. It was positively and significantly correlated with the mRNA levels of genes encoding adeB in strain R2 and an outer membrane protein A (ompA) and biofilm-associated protein (bap) in strain R3 in the presence of PMB. These results provide valuable insights into the biofilm formation potency of clinical isolates of MDRA that depends on efflux pumps and biofilm-related genes and its regulation by antibiotics.}, } @article {pmid29553712, year = {2018}, author = {Dykas, MM and Desai, SK and Patra, A and Motapothula, MR and Poddar, K and Kenney, LJ and Venkatesan, T}, title = {Identification of Biofilm Inhibitors by Screening Combinatorial Libraries of Metal Oxide Thin Films.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {15}, pages = {12510-12517}, doi = {10.1021/acsami.8b02246}, pmid = {29553712}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Metals ; Oxides ; Salmonella typhimurium ; }, abstract = {With the rise in nosocomial infections worldwide, research on materials with an intrinsic ability to inhibit biofilm formation has been generating a great deal of interest. In the present work, we describe how thin film material libraries generated by pulsed laser deposition can be used for simultaneously screening several novel metal oxide mixtures that inhibit biofilm formation in a common human pathogen, Salmonella enterica serovar Typhimurium. We discovered that in a material library constructed using two metal oxides, the net effect on biofilm formation can be modeled as an addition of the activities of the individual oxides weighted to their relative composition at that particular point on the library. In contrast, for similar material libraries constructed using three metal oxides, there was a nonlinear relation between the amount of dominant metal oxide and the formation of Salmonella biofilms. This nonlinearity resulted in several useful metal oxide combinations that were not expected from the weighted average predictions. Our novel application will lead to the discovery of additional alternatives for creating antimicrobial surfaces.}, } @article {pmid29552003, year = {2018}, author = {Chen, XP and Ali, L and Wu, LY and Liu, C and Gang, CX and Huang, QF and Ruan, JH and Bao, SY and Rao, YP and Yu, D}, title = {Biofilm Formation Plays a Role in the Formation of Multidrug-Resistant Escherichia coli Toward Nutrients in Microcosm Experiments.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {367}, pmid = {29552003}, issn = {1664-302X}, abstract = {In this study, microcosms were established to determine the effect of nitrogen (N) and phosphorus (P) on the multidrug resistance and biofilm-forming abilities of Escherichia coli. The expression of biofilm-formation-related genes was detected to establish correlations between genotype and phenotype. Different concentrations of N and P were added to make one control group and four treatment groups. The glass tube method was used to determine biofilm-forming capabilities. Real-time PCR was used to detect the mRNA abundance of six biofilm-formation-related genes in E. coli. No resistant strains were isolated from the control group; meanwhile, multidrug resistance rates were high in the treatment groups. Expression of the biofilm-associated genes luxS, flhD, fliA, motA, and fimH was detected in all treatment groups; however, there was no expression of mqsR. The expression of luxS, flhD, fliA, motA, and fimH significantly correlated with the concentration of N and P, as well as with the appearance and duration of multidrug resistance in different groups. Overall, the results of this study suggest that biofilm-forming ability plays a key role in the formation of multidrug resistance in E. coli after the addition of N and P to a microcosm.}, } @article {pmid29551479, year = {2018}, author = {An, X and Cheng, Y and Huang, M and Sun, Y and Wang, H and Chen, X and Wang, J and Li, D and Li, C}, title = {Treating organic cyanide-containing groundwater by immobilization of a nitrile-degrading bacterium with a biofilm-forming bacterium using fluidized bed reactors.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {237}, number = {}, pages = {908-916}, doi = {10.1016/j.envpol.2018.01.087}, pmid = {29551479}, issn = {1873-6424}, mesh = {Bacteria ; Biofilms/growth & development ; Bioreactors/*microbiology ; China ; Cyanides ; Groundwater/chemistry/*microbiology ; Nitriles/analysis/*metabolism ; Wastewater ; Water Pollutants, Chemical/analysis/*metabolism ; Water Purification/*methods ; }, abstract = {Organic cyanide are widely used as an ingredient in the production of plastics, synthetic rubbers, polymers, pharmaceuticals and pesticides or used in laboratories and industries as solvents. Although nitrile-containing wastewater is subjected to primary and secondary treatments, residual nitriles may slowly seep and further migrate through groundwater, resulting in the micropollution of groundwater by organic pollutants. In this study, water samples were collected from different study areas in North China during a period of 3y (from 2013 to 2015) and analyzed to evaluate organic cyanide (CN[-]) contamination in groundwater. Three parallel lab-scale fluidized bed reactors (FBRs) were tested for their ability to remove organic cyanide from groundwater. The organic cyanide concentration in groundwater increased significantly (P < 0.05) from 2013 to 2015. With an optimal hydraulic residence time (HRT) of 54 min, reactor R3 (inoculated with a nitrile-degrading bacterium, BX2, and a biofilm-forming bacterium, M1) effectively removed 99.8% of CN[-] under steady operation, which was better than that of other reactors. Short-term shutdowns of FBRs had no serious effects on the efficiency of treating organic cyanide. This work demonstrated that the biofilm-forming bacterium could facilitate the fixation of nitrile-degrading bacterium and enhance the efficiency of removing organic cyanide from groundwater.}, } @article {pmid29551382, year = {2018}, author = {Souza, JGS and Beline, T and Matos, AO and Costa Oliveira, BE and Ricomini-Filho, AP and Barão, VAR}, title = {Electrochemical behavior of titanium exposed to a biofilm supplemented with different sucrose concentrations.}, journal = {The Journal of prosthetic dentistry}, volume = {120}, number = {2}, pages = {290-298}, doi = {10.1016/j.prosdent.2017.10.012}, pmid = {29551382}, issn = {1097-6841}, mesh = {*Biofilms/growth & development ; Corrosion ; Dental Implants ; Dental Materials/chemistry ; Dielectric Spectroscopy ; Electrochemical Techniques ; *Electrochemistry ; Hydrogen-Ion Concentration ; *Materials Testing ; Polysaccharides/chemistry ; Saliva, Artificial ; Streptococcus mutans/growth & development/metabolism ; Sucrose/*metabolism ; Surface Properties ; Time Factors ; Titanium/*chemistry ; }, abstract = {STATEMENT OF PROBLEM: Biofilms can reduce the corrosion resistance of titanium because of the bacterial metabolism of fermentable carbohydrates, including sucrose. However, studies evaluating whether biofilms exposed to higher sucrose concentrations can affect the electrochemical behavior of titanium are lacking.

PURPOSE: The purpose of this in vitro study was to test the electrochemical behavior of titanium previously exposed to biofilm supplemented with different sucrose concentrations.

MATERIAL AND METHODS: Streptococcus mutans UA159 biofilms were formed on commercially pure titanium (cpTi) surfaces and supplemented constantly with different sucrose concentrations (0%, 1%, 10%, and 40%) for 7 days (experimental groups) (n=12 per group). CpTi disks without biofilm were used as a control (n=12). The standard electrochemical tests open-circuit potential, electrochemical impedance spectroscopy, and potentiodynamic curve were performed. Data were submitted to ANOVA and the Tukey honestly significant difference (HSD) tests (α=.05).

RESULTS: The biofilm exposed to sucrose had an increased biofilm dry weight (P<.05). The polysaccharide amount and the pH drop were higher in the groups exposed to sucrose (P<.05). No difference was noted between the control and experimental groups for the electrochemical properties of cpTi (P>.05).

CONCLUSIONS: Biofilms exposed to greater carbohydrate concentration did not alter the corrosive behavior of titanium.}, } @article {pmid29549833, year = {2018}, author = {Sun, Y and Guan, Y and Wang, D and Liang, K and Wu, G}, title = {Potential roles of acyl homoserine lactone based quorum sensing in sequencing batch nitrifying biofilm reactors with or without the addition of organic carbon.}, journal = {Bioresource technology}, volume = {259}, number = {}, pages = {136-145}, doi = {10.1016/j.biortech.2018.03.025}, pmid = {29549833}, issn = {1873-2976}, mesh = {4-Butyrolactone/*analogs & derivatives ; *Biofilms ; Carbon ; *Quorum Sensing ; }, abstract = {Two lab-scale nitrifying sequencing batch biofilm reactors, with (SBBR_CN) or without the addition of organics (SBBR_N), were operated to investigate potential roles of acyl homoserine lactone (AHL) based quorum sensing. AHLs of N-[(RS)-3-Hydroxybutyryl]-L-homoserine lactone, N-hexanoyl-L-homoserine lactone (C6-HSL) and N-octanoyl-L-homoserine lactone (C8-HSL) were detected in both reactors. C6-HSL and C8-HSL were also detected in batch experiments, especially with stimulated nitrite oxidizing bacteria activities. Quorum sensing affected biofilm formation mainly through the regulation of extracellular protein production. By the metagenomics analysis, many identified genera and species could participate in quorum sensing, quorum quenching and extracellular polymeric substances (EPS) production. A high quorum quenching activity was obtained in SBBR_CN, whereas a high quorum sensing activity in SBBR_N. Nitrosomonas-like ammonia oxidizing bacteria, Nitrospira-like nitrite oxidizing bacteria and Comammox harbored genes for AHL synthesis and EPS production. Possible relationships among AHLs synthesis, biofilm formation and nitrifiers activity were proposed.}, } @article {pmid29549654, year = {2018}, author = {Roscini, L and Vassiliou, A and Corte, L and Casagrande Pierantoni, D and Robert, V and Tascini, C and Mattana, S and Alunni Cardinali, M and Orfanos, SE and Fioretto, D and Cardinali, G}, title = {Yeast Biofilm as a Bridge Between Medical and Environmental Microbiology Across Different Detection Techniques.}, journal = {Infectious diseases and therapy}, volume = {7}, number = {Suppl 1}, pages = {27-34}, pmid = {29549654}, issn = {2193-8229}, support = {DR348/2015//Fondazione Cassa di Risparmio di Perugia/ ; Amphotericin B treatment of C.parapsilosis biofilm//fellowship program Gilead/ ; }, abstract = {Medical and environmental microbiology have two distinct, although very short, histories stemming, the first from the pioneering works of Sommelweiss, Pasteur, Lister and Koch, the second mainly from the studies of Bejerink and Winogradsky. These two branches of microbiology evolved and specialized separately producing distinct communities and evolving rather different approaches and techniques. The evidence accumulated in recent decades indicate that indeed most of the medically relevant microorganisms have a short circulation within the nosocomial environment and a larger one involving the external, i.e. non-nosocomial, and the hospital environments. This evidence suggests that the differences between approaches should yield to a convergent approach aimed at solving the increasing problem represented by infectious diseases for the increasingly less resistant human communities. Microbial biofilm is one of the major systems used by these microbes to resist the harsh conditions of the natural and anthropic environment, and the even worse ones related to medical settings. This paper presents a brief outline of the converging interest of both environmental and medical microbiology toward a better understanding of microbial biofilm and of the various innovative techniques that can be employed to characterize, in a timely and quantitative manner, these complex structures. Among these, micro-Raman along with micro-Brillouin offer high hopes of describing biofilms both at the subcellular and supercellular level, with the possibility of characterizing the various landscapes of the different biofilms. The possibility of adding a taxonomic identification of the cells comprising the biofilm is a complex aspect presenting several technical issues that will require further studies in the years to come.}, } @article {pmid29546664, year = {2018}, author = {Medrano-Félix, JA and Chaidez, C and Mena, KD and Soto-Galindo, MDS and Castro-Del Campo, N}, title = {Characterization of biofilm formation by Salmonella enterica at the air-liquid interface in aquatic environments.}, journal = {Environmental monitoring and assessment}, volume = {190}, number = {4}, pages = {221}, pmid = {29546664}, issn = {1573-2959}, support = {164601//Consejo Nacional de Ciencia y Tecnología/ ; }, mesh = {Animals ; Biofilms/*growth & development ; *Environmental Monitoring ; Salmonella enterica/*growth & development ; *Water Microbiology ; }, abstract = {Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain. Salmonella Oranienburg and Saintpaul from feces were moderately hydrophobic and motile, while S. Saintpaul from water and the control strain S. Typhimurium showed high hydrophobicity, which helped them form more resistant biofilms than S. Oranienburg. Under stressful conditions, all strains experienced difficulties in forming biofilms. Salmonella Saintpaul and Typhimurium expressed the red dry and rough (RDAR) morphotype and were able to form biofilm at air-liquid interface, contrarily to Oranienburg that showed incomplete rough morphology. This study contributes to the knowledge of biofilm formation as a survival strategy for Salmonella in aquatic environments.}, } @article {pmid29545993, year = {2018}, author = {Jensen, LK and Henriksen, NL and Bjarnsholt, T and Kragh, KN and Jensen, HE}, title = {Combined Staining Techniques for Demonstration of Staphylococcus aureus Biofilm in Routine Histopathology.}, journal = {Journal of bone and joint infection}, volume = {3}, number = {1}, pages = {27-36}, pmid = {29545993}, issn = {2206-3552}, abstract = {Aim: Visualization of Staphylococcus aureus biofilm using histochemical staining and combined histochemistry (HC) and immunohistochemistry (IHC). Methods: The ability of S. aureus S54F9 to form biofilm was tested in vitro. Hereafter, infected bone tissue was collected from two different porcine models of osteomyelitis inoculated with S. aureus strain S54F9. The infection time was five and fifteen days, respectively. Twenty-five different histochemical staining protocols were tested in order to find the stains that could identify extracellular biofilm matrix. Protocols with an optimal visualization of biofilm extracellular matrix were combined with an immunohistochemical protocol based on a specific antibody against S. aureus. The combined protocols were applied to the tissue from the porcine models and to infected bone tissue from a child suffering from chronic staphylococcal osteomyelitis for more than a year. Results:S. aureus S54F9 showed an ability to form biofilm in vitro. Visualization of biofilm, i.e. bacterial cells and extracellular matrix in different colours, was seen when the immunohistochemical protocol was combined with Alcian Blue pH3, Luna and Methyl-pyronin green. The bacterial cells were red to light brown and the extracellular matrix either light blue, blue or orange depending on the histochemical stain. In the porcine models and the human case 10 and 90 percent, respectively, of the bacterial aggregates in a 100x magnification field displayed both the extracellular matrix and the bacterial cells simultaneously in two different colours. Conclusions: A combination of HC and IHC can be used to diagnose and characterise biofilm infections on a routine basis.}, } @article {pmid29544984, year = {2018}, author = {Amend, S and Frankenberger, R and Lücker, S and Domann, E and Krämer, N}, title = {Secondary caries formation with a two-species biofilm artificial mouth.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {34}, number = {5}, pages = {786-796}, doi = {10.1016/j.dental.2018.02.002}, pmid = {29544984}, issn = {1879-0097}, mesh = {Acid Etching, Dental ; *Biofilms ; Bisphenol A-Glycidyl Methacrylate/*chemistry ; Cariostatic Agents/*chemistry ; Dental Caries/*microbiology/therapy ; Dental Restoration, Permanent/*methods ; Glass Ionomer Cements/*chemistry ; Humans ; In Vitro Techniques ; Lacticaseibacillus casei ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Molar, Third ; Polymethacrylic Acids/*chemistry ; Resins, Synthetic/*chemistry ; Saliva, Artificial/chemistry ; Streptococcus mutans ; }, abstract = {OBJECTIVES: The present study aimed to establish Lactobacillus casei in a completely automated Streptococcus mutans-based artificial mouth model and to investigate secondary caries inhibiting properties of glass ionomer cements / resin composite groups in vitro.

METHODS: Sixty extracted, caries-free human third molars were used for preparation of standardized class-V-cavities. Specimens were restored with a resin-modified (Photac Fil; PF) as well as a conventional glass ionomer cement (Ketac Molar; KM) and one resin composite bonded with and without conduction of etch-and-rinse technique (Prime&Bond NT, Ceram X mono; C+ERT, C). Following an incubation in distilled water for 28d at 37°C, specimens were exposed to 10,000 thermocycles (+5 °C/+55°C). A completely automated S. mutans-based (DSM No.: 20523) artificial mouth model was extended by establishment of L. casei (DSM No.: 20021). During microbiological loading, demineralization (4h/d) was caused by acid production resulting from bacterial glycolysis and artificial saliva was used for remineralization (20h/d). For quantitative margin analysis under am SEM, epoxy replicas were produced from impressions taken after thermocycling and after microbiological loading. Specimens were cut in half perpendicularly to restoration surfaces and demineralization depths at restoration margins and in 500μm distance from margins were evaluated by means of a fluorescence microscope (FITC filter).

RESULTS: After microbiological loading, overall demineralization depths in enamel at restoration margin (EM) and in 500μm distance (ED) as well as in cementum/dentin at restoration margin (DM) and in 500μm distance (DD) were measured as follows (μm±SD): PF: EM 42±15, ED 60±17, DM 83±18; DD 127±16; KM: EM 46±22, ED 62±17, DM 104±21, DD 143±28; C+ERT: EM 67±19, ED 61±17, DM 165±31, DD 176±35; C: EM 65±23, ED 64±17, DM 161±27, DD 166±33. For the glass ionomer cements, the overall demineralization depths at restoration margins were significantly lower than in 500μm distance from margins (T-test, p<0.05). Especially at restoration margins in cementum/dentin, the resin composite groups showed significantly larger overall demineralizations than the glass ionomer cements (ANOVA, mod. LSD, p<0.05). Decreases of marginal quality were detected in all groups after microbiological loading (Friedman-test, p<0.05).

SIGNIFICANCE: The refined experimental setup was suitable for production of artificial secondary caries-like lesions. Glass ionomer cements as fluoride-releasing materials may show an inhibition of secondary caries formation to a certain extent.}, } @article {pmid29544734, year = {2018}, author = {Munusamy, K and Vadivelu, J and Tay, ST}, title = {A study on Candida biofilm growth characteristics and its susceptibility to aureobasidin A.}, journal = {Revista iberoamericana de micologia}, volume = {35}, number = {2}, pages = {68-72}, doi = {10.1016/j.riam.2017.07.001}, pmid = {29544734}, issn = {2173-9188}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Biomass ; Candida/*drug effects/physiology ; Candida albicans/drug effects/physiology/ultrastructure ; Candidemia/microbiology ; Candidiasis, Vulvovaginal/microbiology ; Depsipeptides/*pharmacology ; Drug Evaluation, Preclinical ; Drug Resistance, Fungal ; Female ; Humans ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Species Specificity ; }, abstract = {BACKGROUND: Biofilm is known to contribute to the antifungal resistance of Candida yeasts. Aureobasidin A (AbA), a cyclic depsipeptide targeting fungal sphingolipid biosynthesis, has been shown to be effective against several Candida species.

AIMS: The aim of this study was to investigate Candida biofilm growth morphology, its biomass, metabolic activity, and to determine the effects of AbA on the biofilm growth.

METHODS: The biofilm forming ability of several clinical isolates of different Candida species from our culture collection was determined using established methods (crystal violet and XTT assays). The determination of AbA planktonic and biofilm MICs was performed based on a micro-broth dilution method. The anti-biofilm effect of AbA on Candida albicans was examined using field emission scanning electron microscope (FESEM) analysis.

RESULTS: A total of 35 (29.7%) of 118 Candida isolates were regarded as biofilm producers in this study. Candida parapsilosis was the largest producer, followed by Candida tropicalis and C. albicans. Two morphological variants of biofilms were identified in our isolates, with 48.6% of the isolates showing mainly yeast and pseudohyphae-like structures, while the remaining ones were predominantly filamentous forms. The biofilm producers were divided into two populations (low and high), based on the ability in producing biomass and their metabolic activity. Candida isolates with filamentous growth, higher biomass and metabolic activity showed lower AbA MIC50 (at least fourfold), compared to those exhibiting yeast morphology, and lower biomass and metabolic activity. The observation of filament detachment and the almost complete removal of biofilm from AbA-treated C. albicans biofilm in FESEM analysis suggests an anti-biofilm effect of AbA.

CONCLUSIONS: The variability in the growth characteristics of Candida biofilm cultures affects susceptibility to AbA, with higher susceptibility noted in biofilm cultures exhibiting filamentous form and high biomass/metabolic activity.}, } @article {pmid29543339, year = {2018}, author = {Patil, RH and Kalam Khan, FA and Jadhav, K and Damale, M and Akber Ansari, S and Alkahtani, HM and Ali Khan, A and Shinde, SD and Patil, R and Sangshetti, JN}, title = {Fungal biofilm inhibition by piperazine-sulphonamide linked Schiff bases: Design, synthesis, and biological evaluation.}, journal = {Archiv der Pharmazie}, volume = {351}, number = {3-4}, pages = {e1700354}, doi = {10.1002/ardp.201700354}, pmid = {29543339}, issn = {1521-4184}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Bacillus subtilis/drug effects ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Dose-Response Relationship, Drug ; *Drug Design ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Molecular Structure ; Piperazine ; Piperazines/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Schiff Bases/chemistry/pharmacology ; Structure-Activity Relationship ; Sulfanilamide ; Sulfanilamides/chemistry/*pharmacology ; }, abstract = {We report the synthesis of some new piperazine-sulphonamide linked Schiff bases as fungal biofilm inhibitors with antibacterial and antifungal potential. The biofilm inhibition result of Candida albicans proposed that the compounds 6b (IC50 = 32.1 μM) and 6j (IC50 = 31.4 μM) showed higher inhibitory activity than the standard fluconazole (IC50 = 40 μM). Compound 6d (MIC = 26.1 μg/mL) with a chloro group at the para position was found to be the most active antibacterial agent of the series against Bacillus subtilis when compared with the standard ciprofloxacin (MIC = 50 μg/mL). Compound 6j (MIC = 39.6 μg/mL) with an OH(?) group at the ortho position showed more potent antifungal activity as compared to that of the standard fluconazole (IC50 = 50 μM) against C. albicans. Thus, the synthesized compounds 6a-k were found to be potent biofilm inhibitors as well as active antibacterial and antifungal agents. The molecular docking study of the synthesized compounds against the secreted aspartyl protease (SAP5) enzyme of C. albicans exhibited good binding properties. The in silico ADME properties of the synthesized compounds were also analyzed and showed their potential to be developed as potential oral drug candidates.}, } @article {pmid29541068, year = {2018}, author = {Le, KY and Park, MD and Otto, M}, title = {Immune Evasion Mechanisms of Staphylococcus epidermidis Biofilm Infection.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {359}, pmid = {29541068}, issn = {1664-302X}, abstract = {The primary virulence factor of the skin commensal and opportunistic pathogen, Staphylococcus epidermidis, is the ability to form biofilms on surfaces of implanted materials. Much of this microorganism's pathogenic success has been attributed to its ability to evade the innate immune system. The primary defense against S. epidermidis biofilm infection consists of complement activation, recruitment and subsequent killing of the pathogen by effector cells. Among pathogen-derived factors, the biofilm exopolysaccharide polysaccharide intercellular adhesion (PIA), as well as the accumulation-associated protein (Aap), and the extracellular matrix binding protein (Embp) have been shown to modulate effector cell-mediated killing of S. epidermidis. Phenol-soluble modulins (PSMs) constitute the only class of secreted toxins by S. epidermidis, at least one type of which (PSMδ) possesses strong cytolytic properties toward leukocytes. However, through selective production of non-cytolytic subtypes of PSMs, S. epidermidis is able to maintain a low inflammatory infection profile and avoid eradication by the host immune system. Taken together, our emerging understanding of the mechanisms behind immune modulation by S. epidermidis elucidates the microorganism's success in the initial colonization of device surfaces as well as the maintenance of a chronic and indolent course of biofilm infection.}, } @article {pmid29535972, year = {2018}, author = {Abu Khweek, A and Amer, AO}, title = {Factors Mediating Environmental Biofilm Formation by Legionella pneumophila.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {38}, pmid = {29535972}, issn = {2235-2988}, support = {R21 AI113477/AI/NIAID NIH HHS/United States ; R01 HL127651/HL/NHLBI NIH HHS/United States ; }, mesh = {Biodiversity ; *Biofilms ; Environment ; *Environmental Microbiology ; Factor Analysis, Statistical ; Gene Expression Profiling ; Iron/metabolism ; Legionella pneumophila/classification/*physiology ; Legionnaires' Disease/metabolism/microbiology ; Microbial Viability ; Quorum Sensing ; }, abstract = {Legionella pneumophila (L. pneumophila) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems. Biofilm formation by L. pneumophila is advantageous for the pathogen as it leads to persistence, spread, resistance to treatments and an increase in virulence of this bacterium. Furthermore, Legionellosis outbreaks have been associated with the presence of L. pneumophila in biofilms, even after the extensive chemical and physical treatments. In the microbial consortium-containing L. pneumophila among other organisms, several factors either positively or negatively regulate the presence and persistence of L. pneumophila in this bacterial community. Biofilm-forming L. pneumophila is of a major importance to public health and have impact on the medical and industrial sectors. Indeed, prevention and removal protocols of L. pneumophila as well as diagnosis and hospitalization of patients infected with this bacteria cost governments billions of dollars. Therefore, understanding the biological and environmental factors that contribute to persistence and physiological adaptation in biofilms can be detrimental to eradicate and prevent the transmission of L. pneumophila. In this review, we focus on various factors that contribute to persistence of L. pneumophila within the biofilm consortium, the advantages that the bacteria gain from surviving in biofilms, genes and gene regulation during biofilm formation and finally challenges related to biofilm resistance to biocides and anti-Legionella treatments.}, } @article {pmid29535693, year = {2018}, author = {Ahn, KB and Baik, JE and Yun, CH and Han, SH}, title = {Lipoteichoic Acid Inhibits Staphylococcus aureus Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {327}, pmid = {29535693}, issn = {1664-302X}, abstract = {A biofilm is an aggregate of microorganisms in which cells adhere to biological or non-biological surfaces and is responsible for various infectious diseases. Infections caused by Staphylococcus aureus, including pneumonia, endocarditis, and osteomyelitis, are often associated with colonization and biofilm formation. Although lipoteichoic acid (LTA) is involved in biofilm formation, the specific role of LTA is not clearly understood. In this study, we demonstrated that LTA released from Lactobacillus plantarum could inhibit S. aureus biofilm formation and aggregation without affecting the growth of S. aureus in various in vitro and in vivo models. L. plantarum LTA (Lp.LTA) also inhibited biofilm formation of S. aureus clinical isolates, including a methicillin-resistant strain. Remarkably, Lp.LTA not only interfered with S. aureus biofilm formation, but it also disrupted a pre-formed biofilm. Mechanism studies demonstrated that Lp.LTA inhibited expression of the ica-operon, which is responsible for the production of poly-N-acetylglucosamine, a key molecule required for S. aureus biofilm development. Lp.LTA increased the release of autoinducer-2 from S. aureus, which contributed to the inhibition of S. aureus biofilm formation. Moreover, Lp.LTA treatment enhanced susceptibility of the biofilm to various antibiotics and to macrophages. Interestingly, Lp.LTA without D-alanine moieties was not able to inhibit biofilm formation by S. aureus. In conclusion, the present study suggests that LTA can inhibit S. aureus biofilm formation, and therefore could be applied for preventing and/or treating infectious diseases caused by S. aureus biofilms.}, } @article {pmid29535412, year = {2018}, author = {Rout, SP and Payne, L and Walker, S and Scott, T and Heard, P and Eccles, H and Bond, G and Shah, P and Bills, P and Jackson, BR and Boxall, SA and Laws, AP and Charles, C and Williams, SJ and Humphreys, PN}, title = {The Impact of Alkaliphilic Biofilm Formation on the Release and Retention of Carbon Isotopes from Nuclear Reactor Graphite.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {4455}, pmid = {29535412}, issn = {2045-2322}, abstract = {[14]C is an important consideration within safety assessments for proposed geological disposal facilities for radioactive wastes, since it is capable of re-entering the biosphere through the generation of [14]C bearing gases. The irradiation of graphite moderators in the UK gas-cooled nuclear power stations has led to the generation of a significant volume of [14]C-containing intermediate level wastes. Some of this [14]C is present as a carbonaceous deposit on channel wall surfaces. Within this study, the potential of biofilm growth upon irradiated and [13]C doped graphite at alkaline pH was investigated. Complex biofilms were established on both active and simulant samples. High throughput sequencing showed the biofilms to be dominated by Alcaligenes sp at pH 9.5 and Dietzia sp at pH 11.0. Surface characterisation revealed that the biofilms were limited to growth upon the graphite surface with no penetration of the deeper porosity. Biofilm formation resulted in the generation of a low porosity surface layer without the removal or modification of the surface deposits or the release of the associated [14]C/[13]C. Our results indicated that biofilm formation upon irradiated graphite is likely to occur at the pH values studied, without any additional release of the associated [14]C.}, } @article {pmid29534199, year = {2018}, author = {Petrovich, M and Chu, B and Wright, D and Griffin, J and Elfeki, M and Murphy, BT and Poretsky, R and Wells, G}, title = {Antibiotic resistance genes show enhanced mobilization through suspended growth and biofilm-based wastewater treatment processes.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {5}, pages = {}, doi = {10.1093/femsec/fiy041}, pmid = {29534199}, issn = {1574-6941}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/*genetics/growth & development ; Bacterial Physiological Phenomena ; Bacterial Proteins/*genetics/metabolism ; Biofilms/drug effects ; *Drug Resistance, Bacterial ; Genes, Bacterial ; Metagenomics ; Wastewater/analysis/*microbiology ; }, abstract = {Wastewater treatment plants (WWTPs) are known to harbor antibiotic resistance genes (ARGs) that are disseminated into the environment via effluent. However, few studies have compared abundance, mobilization and selective pressures for ARGs in WWTPs as a function of variations in secondary treatment bioprocesses. We used shotgun metagenomics to provide a comprehensive analysis of ARG composition, relationship to mobile genetic elements and co-occurrences with antibiotic production genes (APGs) throughout two full-scale municipal WWTPs, one of which employs biofilm-based secondary treatment and another that uses a suspended growth system. Results showed that abundances of ARGs declined by over 90% per genome equivalent in both types of wastewater treatment processes. However, the fractions of ARGs associated with mobile genetic elements increased substantially between influent and effluent in each plant, indicating significant mobilization of ARGs throughout both treatment processes. Strong positive correlations between ARGs and APGs were found for the aminoglycoside antibiotic class in the suspended growth system and for the streptogramin antibiotic class in the biofilm system. The biofilm and suspended growth WWTPs exhibited similarities in ARG abundances, composition and mobilization trends. However, clear differences were observed for within-plant ARG persistence. These findings suggest that both biofilm and suspended growth-based WWTPs may promote genetic mobilization of persistent ARGs that are then disseminated in effluent to receiving water bodies.}, } @article {pmid29533823, year = {2018}, author = {Munck, C and Thierry, E and Gräßle, S and Chen, SH and Ting, ASY}, title = {Biofilm formation of filamentous fungi Coriolopsis sp. on simple muslin cloth to enhance removal of triphenylmethane dyes.}, journal = {Journal of environmental management}, volume = {214}, number = {}, pages = {261-266}, doi = {10.1016/j.jenvman.2018.03.025}, pmid = {29533823}, issn = {1095-8630}, mesh = {Biodegradation, Environmental ; *Biofilms ; Coloring Agents/*isolation & purification ; *Fungi ; Gentian Violet ; Trityl Compounds/*isolation & purification ; }, abstract = {The isolate Coriolopsis sp. (1c3) was cultured on muslin cloth to induce formation of filamentous biofilm. The biofilm and the free-mycelium forms (control) were then used to treat two triphenylmethane dyes; Cotton Blue (CB) and Crystal Violet (CV). The biofilm comprised primarily of a compact mass of mycelium while sparse mycelium network was detected in free-mycelium forms. Results revealed significant decolourization activities by filamentous biofilm of 1c3 for CB (79.6%) and CV (85.1%), compared to free-mycelium forms (72.6 and 58.3%, for CB and CV, respectively). Biodegradation occurred in both biofilm and free-mycelium forms. FTIR spectra revealed that biofilm formation (stacking of mycelium), did not have severe implications to the number and types of functional groups available for dye biosorption. The findings here suggested that formation of biofilm in 1c3 was induced effectively on muslin cloth, leading to enhanced decolourization activities. This technology is simple, feasible and can be adopted and further improved to obtain biofilm to enhance their dye removal efficiency in aqueous solutions.}, } @article {pmid29533610, year = {2018}, author = {Luo, JH and Chen, H and Hu, S and Cai, C and Yuan, Z and Guo, J}, title = {Microbial Selenate Reduction Driven by a Denitrifying Anaerobic Methane Oxidation Biofilm.}, journal = {Environmental science & technology}, volume = {52}, number = {7}, pages = {4006-4012}, doi = {10.1021/acs.est.7b05046}, pmid = {29533610}, issn = {1520-5851}, mesh = {Anaerobiosis ; *Biofilms ; *Methane ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; Selenic Acid ; }, abstract = {Anaerobic oxidation of methane (AOM) plays a crucial role in controlling the flux of methane from anoxic environments. Sulfate-, nitrite-, nitrate-, and iron-dependent methane oxidation processes have been considered to be responsible for the AOM activities in anoxic niches. We report that nitrate-reducing AOM microorganisms, enriched in a membrane biofilm bioreactor, are able to couple selenate reduction to AOM. According to ion chromatography, X-ray photoelectron spectroscopy, and long-term bioreactor performance, we reveal that soluble selenate was reduced to nanoparticle elemental selenium. High-throughput 16S rRNA gene sequencing indicates that Candidatus Methanoperedens and Candidatus Methylomirabilis remained the only known methane-oxidizing microorganisms after nitrate was switched to selenate, suggesting that these organisms could couple anaerobic methane oxidation to selenate reduction. Our findings suggest a possible link between the biogeochemical selenium and methane cycles.}, } @article {pmid29531041, year = {2018}, author = {Diehl, A and Roske, Y and Ball, L and Chowdhury, A and Hiller, M and Molière, N and Kramer, R and Stöppler, D and Worth, CL and Schlegel, B and Leidert, M and Cremer, N and Erdmann, N and Lopez, D and Stephanowitz, H and Krause, E and van Rossum, BJ and Schmieder, P and Heinemann, U and Turgay, K and Akbey, Ü and Oschkinat, H}, title = {Structural changes of TasA in biofilm formation of Bacillus subtilis.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {13}, pages = {3237-3242}, pmid = {29531041}, issn = {1091-6490}, mesh = {Bacillus subtilis/chemistry/*physiology ; Bacterial Proteins/*chemistry/metabolism ; Biofilms/*growth & development ; Calorimetry ; Crystallography, X-Ray ; Hydrogen-Ion Concentration ; Magnetic Resonance Spectroscopy ; Metalloendopeptidases/chemistry ; Microscopy, Electron ; Models, Molecular ; Molecular Weight ; Protein Conformation ; Structural Homology, Protein ; Ultracentrifugation ; }, abstract = {Microorganisms form surface-attached communities, termed biofilms, which can serve as protection against host immune reactions or antibiotics. Bacillus subtilis biofilms contain TasA as major proteinaceous component in addition to exopolysaccharides. In stark contrast to the initially unfolded biofilm proteins of other bacteria, TasA is a soluble, stably folded monomer, whose structure we have determined by X-ray crystallography. Subsequently, we characterized in vitro different oligomeric forms of TasA by NMR, EM, X-ray diffraction, and analytical ultracentrifugation (AUC) experiments. However, by magic-angle spinning (MAS) NMR on live biofilms, a swift structural change toward only one of these forms, consisting of homogeneous and protease-resistant, β-sheet-rich fibrils, was observed in vivo. Thereby, we characterize a structural change from a globular state to a fibrillar form in a functional prokaryotic system on the molecular level.}, } @article {pmid29531022, year = {2018}, author = {}, title = {Retraction: "Haemophilus influenzae responds to glucocorticoids used in asthma therapy by modulation of biofilm formation and antibiotic resistance".}, journal = {EMBO molecular medicine}, volume = {10}, number = {4}, pages = {}, pmid = {29531022}, issn = {1757-4684}, abstract = {Chris S Earl, Teh Wooi Keong, Shi-qi An, Sarah Murdoch, Yvonne McCarthy, Junkal Garmendia, Joseph Ward, J Maxwell Dow, Liang Yang, George A O'Toole & Robert P RyanThe above article, published May 20 2015 in EMBO Molecular Medicine, has been retracted by agreement between the authors of the study, CSE, TWK, SQA, SM, YMcC, JG, JW, JMD, LY, RPR, the journal Chief Editor and the EMBO Head of Scientific Publications in accordance with the outcomes of independent investigations conducted by the University of Dundee and University College Cork.GAO'T disagrees with the text of this retraction notice, albeit not with the retraction.The following issues are noted: Table 1 contains clinical data described in the paper as being derived from a cohort of asthma patients. However, the provenance of this data is unclear. Based on the evidence available, the University of Dundee investigation concluded that the majority of the patient cohort is likely to be a subset of a cohort of cystic fibrosis patients reported in PLoS One 8(12): e82432 (https://doi.org/10.1371/journal.pone.0082432), although in a number of cases the patient's gender is at odds between the two reports.The RNAseq data are unavailable on the European Nucleotide Archive under the reported accession number ERG003569. RNAseq data were uploaded with accession number ERS654066 before publication.The paper describes use of both prednisolone and prednisone, yet only the latter was used in the study.}, } @article {pmid29530854, year = {2018}, author = {Luther, MK and Parente, DM and Caffrey, AR and Daffinee, KE and Lopes, VV and Martin, ET and LaPlante, KL}, title = {Clinical and Genetic Risk Factors for Biofilm-Forming Staphylococcus aureus.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {5}, pages = {}, pmid = {29530854}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Genotype ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Risk Factors ; Staphylococcus aureus/*drug effects ; }, abstract = {The molecular and clinical factors associated with biofilm-forming methicillin-resistant Staphylococcus aureus (MRSA) are incompletely understood. Biofilm production for 182 MRSA isolates obtained from clinical culture sites (2004 to 2013) was quantified. Microbiological toxins, pigmentation, and genotypes were evaluated, and patient demographics were collected. Logistic regression was used to quantify the effect of strong biofilm production (versus weak biofilm production) on clinical outcomes and independent predictors of a strong biofilm. Of the isolates evaluated, 25.8% (47/182) produced strong biofilms and 40.7% (74/182) produced weak biofilms. Strong biofilm-producing isolates were more likely to be from multilocus sequence typing (MLST) clonal complex 8 (CC8) (34.0% versus 14.9%; P = 0.01) but less likely to be from MLST CC5 (48.9% versus 73.0%; P = 0.007). Predictors for strong biofilms were spa type t008 (adjusted odds ratio [aOR], 4.54; 95% confidence interval [CI], 1.21 to 17.1) and receipt of chemotherapy or immunosuppressants in the previous 90 days (aOR, 33.6; 95% CI, 1.68 to 673). Conversely, patients with high serum creatinine concentrations (aOR, 0.33; 95% CI, 0.15 to 0.72) or who previously received vancomycin (aOR, 0.03; 95% CI, 0.002 to 0.39) were less likely to harbor strong biofilm-producing MRSA. Beta-toxin-producing isolates (aOR, 0.31; 95% CI, 0.11 to 0.89) and isolates with spa type t895 (aOR, 0.02 95% CI, <0.001 to 0.47) were less likely to produce strong biofilms. Patient outcomes also varied between the two groups. Specifically, patients with strong biofilm-forming MRSA were significantly more likely to be readmitted within 90 days (aOR, 5.43; 95% CI, 1.69 to 17.4) but tended to have decreased 90-day mortality (aOR, 0.36; 95% CI, 0.12 to 1.06). Patients that harbored t008 and received immunosuppressants were more likely to have strong biofilm-producing MRSA isolates. Clinically, patients with strong biofilm-forming MRSA were less likely to die at 90 days but five times more likely to be readmitted.}, } @article {pmid29529252, year = {2018}, author = {Orell, A and Tripp, V and Aliaga-Tobar, V and Albers, SV and Maracaja-Coutinho, V and Randau, L}, title = {A regulatory RNA is involved in RNA duplex formation and biofilm regulation in Sulfolobus acidocaldarius.}, journal = {Nucleic acids research}, volume = {46}, number = {9}, pages = {4794-4806}, pmid = {29529252}, issn = {1362-4962}, mesh = {Biofilms/*growth & development ; Exoribonucleases ; Gene Deletion ; Gene Expression Profiling ; RNA Stability ; RNA, Double-Stranded/genetics/*metabolism ; RNA, Untranslated/genetics/*metabolism ; Sulfolobus acidocaldarius/*genetics/metabolism/physiology ; }, abstract = {Non-coding RNAs (ncRNA) are involved in essential biological processes in all three domains of life. The regulatory potential of ncRNAs in Archaea is, however, not fully explored. In this study, RNA-seq analyses identified a set of 29 ncRNA transcripts in the hyperthermophilic archaeon Sulfolobus acidocaldarius that were differentially expressed in response to biofilm formation. The most abundant ncRNA of this set was found to be resistant to RNase R treatment (RNase R resistant RNA, RrrR(+)) due to duplex formation with a reverse complementary RNA (RrrR(-)). The deletion of the RrrR(+) gene resulted in significantly impaired biofilm formation, while its overproduction increased biofilm yield. RrrR(+) was found to act as an antisense RNA against the mRNA of a hypothetical membrane protein. The RrrR(+) transcript was shown to be stabilized by the presence of the RrrR(-) strand in S. acidocaldarius cell extracts. The accumulation of these RrrR duplexes correlates with an apparent absence of dsRNA degrading RNase III domains in archaeal proteins.}, } @article {pmid29528303, year = {2018}, author = {Rittmann, BE and Boltz, JP and Brockmann, D and Daigger, GT and Morgenroth, E and Sørensen, KH and Takács, I and van Loosdrecht, M and Vanrolleghem, PA}, title = {A framework for good biofilm reactor modeling practice (GBRMP).}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {5-6}, pages = {1149-1164}, doi = {10.2166/wst.2018.021}, pmid = {29528303}, issn = {0273-1223}, mesh = {Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bioreactors/*standards ; Calibration ; *Models, Biological ; Waste Disposal, Fluid/*methods/standards ; Wastewater ; }, abstract = {A researcher or practitioner can employ a biofilm model to gain insight into what controls the performance of a biofilm process and for optimizing its performance. While a wide range of biofilm-modeling platforms is available, a good strategy is to choose the simplest model that includes sufficient components and processes to address the modeling goal. In most cases, a one-dimensional biofilm model provides the best balance, and good choices can range from hand-calculation analytical solutions, simple spreadsheets, and numerical-method platforms. What is missing today is clear guidance on how to apply a biofilm model to obtain accurate and meaningful results. Here, we present a five-step framework for good biofilm reactor modeling practice (GBRMP). The first four steps are (1) obtain information on the biofilm reactor system, (2) characterize the influent, (3) choose the plant and biofilm model, and (4) define the conversion processes. Each step demands that the model user understands the important components and processes in the system, one of the main benefits of doing biofilm modeling. The fifth step is to calibrate and validate the model: System-specific model parameters are adjusted within reasonable ranges so that model outputs match actual system performance. Calibration is not a simple 'by the numbers' process, and it requires that the modeler follows a logical hierarchy of steps. Calibration requires that the adjusted parameters remain within realistic ranges and that the calibration process be carried out in an iterative manner. Once each of steps 1 through 5 is completed satisfactorily, the calibrated model can be used for its intended purpose, such as optimizing performance, trouble-shooting poor performance, or gaining deeper understanding of what controls process performance.}, } @article {pmid29527517, year = {2018}, author = {Zheng, JX and Lin, ZW and Chen, C and Chen, Z and Lin, FJ and Wu, Y and Yang, SY and Sun, X and Yao, WM and Li, DY and Yu, ZJ and Jin, JL and Qu, D and Deng, QW}, title = {Biofilm Formation in Klebsiella pneumoniae Bacteremia Strains Was Found to be Associated with CC23 and the Presence of wcaG.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {21}, pmid = {29527517}, issn = {2235-2988}, mesh = {Adult ; Anti-Bacterial Agents/pharmacology ; Bacteremia/*microbiology ; *Biofilms ; Female ; Gene Silencing ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/classification/drug effects/*physiology ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Multilocus Sequence Typing ; Virulence/genetics ; Virulence Factors/*genetics/metabolism ; Young Adult ; }, abstract = {Klebsiella pneumoniae bacteremia biofilm traits and distribution characteristics have not been clarified. This study aimed to determine the prevalence and characteristics of K. pneumoniae bacteremia biofilm formation (BF) and to explore the virulence factors associated with K. pneumoniae BF. A total of 250 K. pneumoniae bacteremia isolates were collected from patients in Shenzhen and Shanghai, China. Virulence genes in their genomes were detected by PCR. The isolates were subjected to multilocus sequence typing (MLST) and clonal complex (CC) classification based on housekeeping genes. Biofilms were detected by crystal violet staining. Greater BF was observed in isolates from young adults (<40 years old) than in those from seniors (≥65 years old; P = 0.002). MLST yielded 65 different sequence types (STs), with the most represented STs being ST11, ST23, and ST65, and the main CCs were CC23 and CC65; CC23 isolates exhibited greater BF than CC65 or ST11 isolates (both P < 0.001). BF was more pronounced among magA(K1), aero+, rmpA+, rmpA2+, allS+, wcaG+, and iutA+ isolates than in isolates that were negative for these virulence factors. Multivariate regression analysis revealed only wcaG as an independent risk factor for BF (odds ratio 11.426, P < 0.001), and BF was decreased when wcaG was silenced by antisense RNA. In conclusion, BF in K. pneumoniae bacteremia isolates was found to be associated with CC23 classification and the presence of the wcaG virulence factor gene.}, } @article {pmid29526668, year = {2018}, author = {Al-Dulaijan, YA and Cheng, L and Weir, MD and Melo, MAS and Liu, H and Oates, TW and Wang, L and Xu, HHK}, title = {Novel rechargeable calcium phosphate nanocomposite with antibacterial activity to suppress biofilm acids and dental caries.}, journal = {Journal of dentistry}, volume = {72}, number = {}, pages = {44-52}, doi = {10.1016/j.jdent.2018.03.003}, pmid = {29526668}, issn = {1879-176X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Benzhydryl Compounds/pharmacology ; Benzoates ; Biofilms/*drug effects ; Calcium Phosphates/*pharmacology ; Camphor/analogs & derivatives/pharmacology ; Colony Count, Microbial ; Composite Resins/pharmacology ; Dental Caries/*drug therapy ; Dental Plaque/microbiology ; Humans ; Lactic Acid/metabolism ; Materials Testing ; Methacrylates/pharmacology ; Nanocomposites/*chemistry ; Nanoparticles/chemistry ; Saliva ; Tooth Remineralization ; para-Aminobenzoates/pharmacology ; }, abstract = {OBJECTIVE: Rechargeable calcium phosphate (CaP) composites were developed recently. However, none of the rechargeable CaP composites was antibacterial. The objectives of this study were to develop the first rechargeable CaP composite that was antibacterial, and to investigate the effects of adding dimethylaminohexadecyl methacrylate (DMAHDM) into rechargeable CaP composite on ion rechargeability and re-release as well as biofilm properties.

METHODS: DMAHDM was synthesized via a Menschutkin reaction. Nanoparticles of amorphous calcium phosphate (NACP) were synthesized using a spray-drying technique. The resin contained ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM). Two composites were fabricated: rechargeable NACP composite, and rechargeable NACP-DMAHDM composite. Mechanical properties and ion release and recharge were measured. A dental plaque microcosm biofilm model using saliva was tested.

RESULTS: Flexural strength and elastic modulus of rechargeable NACP and NACP-DMAHDM composites matched commercial control composite (p > 0.1). NACP-DMAHDM inhibited biofilm metabolic activity and lactic acid, and reduced biofilm colony-forming units (CFU) by 3-4 log. NACP and NACP-DMAHDM showed similar Ca and P ion recharge and re-release (p > 0.1). Therefore, adding DMAHDM did not compromise the ion rechargeability. One recharge yielded continuous release for 42 d. The release was maintained at the same level with increasing number of recharge cycles, indicating long-term ion release and remineralization capability.

CONCLUSIONS: The first CaP rechargeable and antibacterial composite was developed. Adding DMAHDM into the rechargeable NACP composite did not adversely affect the Ca and P ion release and recharge, and the composite had much less biofilm growth and lactic acid production, with CFU reduction by 3-4 log.

CLINICAL SIGNIFICANCE: This novel CaP rechargeable composite with long-term remineralization and antibacterial properties is promising for tooth restorations to inhibit caries.}, } @article {pmid29526565, year = {2018}, author = {Rajkumari, J and Borkotoky, S and Murali, A and Suchiang, K and Mohanty, SK and Busi, S}, title = {Attenuation of quorum sensing controlled virulence factors and biofilm formation in Pseudomonas aeruginosa by pentacyclic triterpenes, betulin and betulinic acid.}, journal = {Microbial pathogenesis}, volume = {118}, number = {}, pages = {48-60}, doi = {10.1016/j.micpath.2018.03.012}, pmid = {29526565}, issn = {1096-1208}, mesh = {Alginates/analysis ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/*growth & development ; Caenorhabditis elegans/microbiology ; Chitinases/metabolism ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Drug Resistance, Multiple, Bacterial/genetics ; Genes, Bacterial ; Glucuronic Acid/analysis ; Glycolipids/analysis ; Hexuronic Acids/analysis ; Hydrophobic and Hydrophilic Interactions ; Indoles ; Metalloendopeptidases/metabolism ; Metalloproteases/metabolism ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Pentacyclic Triterpenes/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Pseudomonas Infections/drug therapy/microbiology/veterinary ; Pseudomonas aeruginosa/*drug effects/metabolism/pathogenicity ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects ; Survival Analysis ; Trans-Activators/metabolism ; Triterpenes/*pharmacology ; Virulence/drug effects ; Virulence Factors/*metabolism ; Betulinic Acid ; }, abstract = {The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P. aeruginosa infection. Hence, targeting QS circuit offers an effective intervention to the ever increasing problem of drug resistant pathogens. In the present study, the pentacyclic triterpenes i.e. Betulin (BT) and Betulinic acid (BA) exhibited significant attenuation in production of QS-regulated virulence factors and biofilm formation in P. aeruginosa, at the sub-lethal concentration. The test compound remarkably interfered in initial stages of biofilm development by decreasing the exopolysaccharide production and cell surface hydrophobicity. Based on the in vivo studies, the test compounds notably enhanced the survival of Caenorhabditis elegans infected with P. aeruginosa. Furthermore, molecular docking analysis revealed that BT and BA can act as a strong competitive inhibitor for QS receptors, LasR and RhlR. The findings suggest that BT and BA can serve as potential anti-infectives in the controlling chronic infection of P. aeruginosa.}, } @article {pmid29524964, year = {2018}, author = {Vargas Buonfiglio, LG and Borcherding, JA and Frommelt, M and Parker, GJ and Duchman, B and Vanegas Calderón, OG and Fernandez-Ruiz, R and Noriega, JE and Stone, EA and Gerke, AK and Zabner, J and Comellas, AP}, title = {Airway surface liquid from smokers promotes bacterial growth and biofilm formation via iron-lactoferrin imbalance.}, journal = {Respiratory research}, volume = {19}, number = {1}, pages = {42}, pmid = {29524964}, issn = {1465-993X}, support = {P01 HL091842/HL/NHLBI NIH HHS/United States ; P30 ES005605/ES/NIEHS NIH HHS/United States ; K23 HL114640/HL/NHLBI NIH HHS/United States ; K01 HL080966/HL/NHLBI NIH HHS/United States ; N01AI30040/AI/NIAID NIH HHS/United States ; KO1HL080966/RR/NCRR NIH HHS/United States ; NO1-AI-30040-01//National Institute of Allergy and Infectious Diseases/International ; P30 DK054759/DK/NIDDK NIH HHS/United States ; UL1RR024979/RR/NCRR NIH HHS/United States ; FY 2010//Center for Health Effects of Environmental Contamination Seed Grants/International ; UL1 RR024979/RR/NCRR NIH HHS/United States ; }, mesh = {Adolescent ; Adult ; Biofilms/drug effects/*growth & development ; Bronchoalveolar Lavage Fluid/chemistry ; Female ; Humans ; Iron/*metabolism ; Lactoferrin/*metabolism/pharmacology ; Male ; Middle Aged ; Pseudomonas aeruginosa/drug effects/*growth & development ; Smokers ; Smoking/*metabolism ; Staphylococcus aureus/drug effects/*growth & development ; Young Adult ; }, abstract = {BACKGROUND: Smoking is a leading cause of respiratory infections worldwide. Tobacco particulate matter disrupts iron homeostasis in the lungs and increases the iron content in the airways of smokers. The airway epithelia secrete lactoferrin to quench iron required for bacteria to proliferate and cause lung infections. We hypothesized that smokers would have increased bacterial growth and biofilm formation via iron lactoferrin imbalance.

METHODS: We collected bronchoalveolar lavage (BAL) samples from non-smokers and smokers. We challenged these samples using a standard inoculum of Staphylococcus aureus and Pseudomonas aeruginosa and quantified bacterial growth and biofilm formation. We measured both iron and lactoferrin in the samples. We investigated the effect of supplementing non-smoker BAL with cigarette smoke extract (CSE) or ferric chloride and the effect of supplementing smoker BAL with lactoferrin on bacterial growth and biofilm formation.

RESULTS: BAL from smokers had increased bacterial growth and biofilm formation compared to non-smokers after both S. aureus and P. aeruginosa challenge. In addition, we found that samples from smokers had a higher iron to lactoferrin ratio. Supplementing the BAL of non-smokers with cigarette smoke extract and ferric chloride increased bacterial growth. Conversely, supplementing the BAL of smokers with lactoferrin had a concentration-dependent decrease in bacterial growth and biofilm formation.

CONCLUSION: Cigarette smoking produces factors which increase bacterial growth and biofilm formation in the BAL. We propose that smoking disrupts the iron-to-lactoferrin in the airways. This finding offers a new avenue for potential therapeutic interventions to prevent respiratory infections in smokers.}, } @article {pmid29524549, year = {2018}, author = {Rajivgandhi, G and Vijayan, R and Maruthupandy, M and Vaseeharan, B and Manoharan, N}, title = {Antibiofilm effect of Nocardiopsis sp. GRG 1 (KT235640) compound against biofilm forming Gram negative bacteria on UTIs.}, journal = {Microbial pathogenesis}, volume = {118}, number = {}, pages = {190-198}, doi = {10.1016/j.micpath.2018.03.011}, pmid = {29524549}, issn = {1096-1208}, mesh = {Actinobacteria/*chemistry/*metabolism ; Anti-Bacterial Agents/*chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/drug effects/ultrastructure ; Cell Wall/drug effects/ultrastructure ; Chromobacterium/chemistry/metabolism ; Escherichia coli/cytology/drug effects ; Gram-Negative Bacteria/*drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Proteus mirabilis/cytology/drug effects ; Quorum Sensing/drug effects ; Urinary Tract Infections/*microbiology ; beta-Lactamases ; }, abstract = {Urinary tract infections (UTIs) are diverse public health complication and caused by range of pathogens, however mostly Gram negative bacteria cause significant life threatening risks to different populations. The prevalence rate and antimicrobial resistance among the Gram negative uropathogens alarmed significantly heighten the economic burden of these infections. In this study, we investigated the antibiofilm efficiency of Pyrrolo [1,2-a] pyrazine-1,4-dione,hexahydro-3-(2-methylpropyl) extracted from endophytic actinomycetes Nocardiopsis sp. GRG 1 (KT235640) against P. mirabilis and E. coli. The extracted compound was characterized through TLC, HPLC, GC-MS, LC-MS and confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM). The compound, Pyrrolo [1,2-a] pyrazine-1, 4-dione, hexahydro-3-(2-methylpropyl) inhibits both bacterial biofilm formation as well as reduces the viability of preformed biofilms. Furthermore, CLSM image shows cell shrinkage, disorganized cell membrane and loss of viability. The SEM result also confirms the cell wall degradation in treated cells of the bacteria. Hence, the Pyrrolo [1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) is active against P. mirabilis and E. coli.}, } @article {pmid29524516, year = {2018}, author = {Kalia, M and Yadav, VK and Singh, PK and Sharma, D and Narvi, SS and Agarwal, V}, title = {Exploring the impact of parthenolide as anti-quorum sensing and anti-biofilm agent against Pseudomonas aeruginosa.}, journal = {Life sciences}, volume = {199}, number = {}, pages = {96-103}, doi = {10.1016/j.lfs.2018.03.013}, pmid = {29524516}, issn = {1879-0631}, mesh = {Anti-Inflammatory Agents, Non-Steroidal/pharmacology ; Biofilms/*drug effects/growth & development ; Microbial Sensitivity Tests/methods ; Molecular Docking Simulation/*methods ; Protein Structure, Secondary ; Pseudomonas aeruginosa/chemistry/*drug effects/physiology ; Quorum Sensing/*drug effects/physiology ; Sesquiterpenes/*pharmacology ; }, abstract = {AIMS: Pseudomonas aeruginosa is a well-known pathogen responsible for various infections due to its capability to develop biofilm and various virulent phenotypes that are regulated by quorum sensing. Pathogenesis of the bacteria may be halted by interfering with the signaling molecules and the quorum sensing receptors. Therefore, the present study explores the potential of parthenolide, a sesquiterpene lactone of feverfew plant, as a promising candidate against P. aeruginosa PAO1 associated virulence factors and biofilm.

MAIN METHODS: Effect of parthenolide on virulence and biofilm formation of P. aeruginosa was studied using standard protocols. Mechanism of action was studied using Real-time PCR as well as molecular docking studies.

KEY FINDINGS: Significant decrease in virulence factors and biofilm formation was observed when treated with the sub-MIC concentration (1 mM) of parthenolide. Gene expression studies showed the down-regulation of autoinducer synthase (lasI, rhlI) as well as their receptors (lasR and rhlR) with remarked repression of lasR by 57% compared to the control. Biofilm-associated fluorescent microscopic studies after staining with FITC-ConA and propidium iodide showed reduced extracellular polymeric substance (EPS) production and killing of bacterial cells after treatment with parthenolide.

SIGNIFICANCE: The study is important as it reports for the first time the potential of parthenolide as an anti-quorum and anti-biofilm agent. This study will be helpful in designing of new quorum sensing inhibitors that help in the eradication of infections and can be given in combination with the antibiotics.}, } @article {pmid29521641, year = {2018}, author = {Kim, D and Namen Ii, W and Moore, J and Buchanan, M and Hayes, V and Myntti, MF and Hakaim, A}, title = {Clinical Assessment of a Biofilm-disrupting Agent for the Management of Chronic Wounds Compared With Standard of Care: A Therapeutic Approach.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {30}, number = {5}, pages = {120-130}, pmid = {29521641}, issn = {1943-2704}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Chronic Disease/therapy ; Debridement ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Standard of Care ; Treatment Outcome ; Wound Healing/*drug effects/physiology ; Wound Infection/*drug therapy/*microbiology ; Wounds and Injuries/*drug therapy/*microbiology ; }, abstract = {OBJECTIVE: The authors study the use of a biofilm-disrupting wound gel designed for wound management to determine if disrupting chronic wound biofilm would be therapeutically efficacious.

MATERIALS AND METHODS: This prospective, randomized, open-label clinical trial was performed from September 2014 through March 2016. Forty-three patients (22 experimental, 21 control) with chronic, recalcitrant wounds were randomized to a 12-week treatment with a biofilm-disrupting wound gel (experimental) or a broad-spectrum antimicrobial ointment (control). The wound healing rate was assessed by measuring wound size reduction and wound closure rates.

RESULTS: Wound size in the experimental group decreased significantly with a 71% reduction in wound area compared with 24% for the control (P < .001). Wound closure was attained in more than half of the patients (14) treated with the experimental product. Fifty-three percent of these patients achieved closure by 12 weeks as opposed to 17% for the control (P < .01). No adverse events related to the experimental product were recorded, but 2 adverse reactions occurred with the control.

CONCLUSIONS: The combination of the experimental product and wound debridement significantly improved wound healing rates by disrupting the biofilm, which protects multispecies bacteria within a chronic wound. Given the significant wound size reduction and closure rates observed in these long-term, nonhealing wounds, as well as the lack of related serious adverse events, the investigators believe the biofilm-disrupting wound gel to be a safe and effective treatment for recalcitrant chronic wounds.}, } @article {pmid29520965, year = {2019}, author = {Thet, NT and Wallace, L and Wibaux, A and Boote, N and Jenkins, ATA}, title = {Development of a mixed-species biofilm model and its virulence implications in device related infections.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {107}, number = {1}, pages = {129-137}, doi = {10.1002/jbm.b.34103}, pmid = {29520965}, issn = {1552-4981}, support = {MR/N006496/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {*Bacteria/growth & development/pathogenicity ; Bacterial Infections/*metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Equipment Contamination ; *Membranes, Artificial ; *Models, Biological ; Porosity ; Virulence Factors/metabolism ; }, abstract = {It is becoming increasingly accepted that to understand and model the bacterial colonization and infection of abiotic surfaces requires the use of a biofilm model. There are many bacterial colonizations by at least two primary species, however this is difficult to model in vitro. This study reports the development of a simple mixed-species biofilm model using strains of two clinically significant bacteria: Staphylococcus aureus and Pseudomonas aeruginosa grown on nanoporous polycarbonate membranes on nutrient agar support. Scanning electron microscopy revealed the complex biofilm characteristics of two bacteria blending in extensive extracellular matrices. Using a prototype wound dressing which detects cytolytic virulence factors, the virulence secretion of 30 single and 40 mixed-species biofilms was tested. P. aeruginosa was seen to out-compete S. aureus, resulting in a biofilm with P. aeruginosa dominating. In situ growth of mixed-species biofilm under prototype dressings showed a real-time correlation between the viable biofilm population and their associated virulence factors, as seen by dressing fluorescent assay. This paper aims to provide a protocol for scientists working in the field of device related infection to create mixed-species biofilms and demonstrate that such biofilms are persistently more virulent in real infections. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 129-137, 2019.}, } @article {pmid29520781, year = {2018}, author = {Qi, H and Li, B and Wang, H and Cai, Q and Quan, X and Cui, Y and Meng, W}, title = {Effects of d-valine on periodontal or peri-implant pathogens: Porphyromonas gingivalis biofilm.}, journal = {Journal of periodontology}, volume = {89}, number = {3}, pages = {303-314}, doi = {10.1002/JPER.17-0405}, pmid = {29520781}, issn = {1943-3670}, mesh = {Biofilms ; Humans ; Microscopy, Electron, Scanning ; *Periodontal Diseases ; *Porphyromonas gingivalis ; Valine ; }, abstract = {BACKGROUND: When presented with a surface or an interface, bacteria often grow as biofilms in which cells are held together by an extracellular matrix. Biofilm formation on implants is an initiating factor for their failure. Porphyromonas gingivalis is the primary etiologic bacteria of initiation and progression of periodontal disease. This microorganism is also the risk factor of many systemic diseases, such as cardiovascular disease, diabetes, and pulmonary infection. To date, no medication that can remove such biofilm has been accepted for clinical use. D-valine (D-val) can reportedly inhibit the formation of biofilm and/or trigger the scattering of mature biofilm. Accordingly, this study investigated the effects of d-val on single-species P. gingivalis biofilms in vitro.

METHODS: P. gingivalis grown in brain heart infusion culture with or without d-val was inoculated in 24- or 96-well plates. After incubation for 72 hours, biomass via crystal violet staining, extracellular polysaccharide production by biofilms, and scanning electron microscopy (SEM) were used to determine the d-val concentration that can effectively prevent P. gingivalis biofilm formation.

RESULTS: Experimental results showed that d-val effectively inhibited biofilm formation at concentrations ≥50 mM (mMol/L), and that d-val inhibition increased with increased concentration. Moreover, at high concentrations, the bacterial form changed from the normal baseball form into a rodlike shape. d-val also notably affected extracellular polysaccharide production by P. gingivalis.

CONCLUSIONS: d-val can inhibit P. gingivalis biofilm formation, and high concentrations can affect bacterial morphology.}, } @article {pmid29520550, year = {2018}, author = {Pfendler, S and Munch, T and Bousta, F and Alaoui-Sosse, L and Aleya, L and Alaoui-Sossé, B}, title = {Bleaching of biofilm-forming algae induced by UV-C treatment: a preliminary study on chlorophyll degradation and its optimization for an application on cultural heritage.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {14}, pages = {14097-14105}, pmid = {29520550}, issn = {1614-7499}, mesh = {Biofilms/growth & development/*radiation effects ; *Caves ; Chlorella/growth & development/*radiation effects ; Chlorophyll/metabolism ; France ; *Geologic Sediments/microbiology ; Light ; Microalgae/growth & development/*radiation effects ; Photosynthesis/radiation effects ; *Ultraviolet Rays ; }, abstract = {Green microalgae colonizing stone surfaces represent a major problem for the conservation of heritage monuments, since they lead to biodegradation and aesthetic issues. Previous studies in La Glacière show cave (France) have demonstrated that UV-C may have a strong effect on microalgae, thus leading to chlorophyll bleaching, which was increased when biofilms were maintained under VIS-light condition unlike to those maintained in the dark. To understand the physiological mechanisms underlying this response and in order to optimize in situ treatment, 30 kJ m[-2] UV-C exposure times were applied to Chlorophyta Chlorella sp. and chlorophyll degradation kinetics were then monitored. UV-C irradiation was enough to inhibit photosynthesis and to directly kill all algal cells. Results also showed that chlorophyll a was degraded faster than chlorophyll b and that 14 h were necessary for complete degradation of all the present chlorophyll. In addition, our results highlighted the importance of visible light exposition after UV-C treatment which leading to chlorophyll bleaching. Irradiated algae cultivated in the dark were still green 5 days after treatment while cultivated samples in the light lost their green color after 14 h. An efficient UV-C treatment applicable to show caves and other heritage monuments was proposed.}, } @article {pmid29519624, year = {2018}, author = {Salari, S and Sadat Seddighi, N and Ghasemi Nejad Almani, P}, title = {Evaluation of biofilm formation ability in different Candida strains and anti-biofilm effects of Fe3O4-NPs compared with Fluconazole: an in vitro study.}, journal = {Journal de mycologie medicale}, volume = {28}, number = {1}, pages = {23-28}, doi = {10.1016/j.mycmed.2018.02.007}, pmid = {29519624}, issn = {1773-0449}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development/physiology ; Candida albicans/drug effects ; Candida glabrata/drug effects ; Candida tropicalis/drug effects ; Fluconazole/*pharmacology ; Humans ; In Vitro Techniques ; Magnetite Nanoparticles/*chemistry ; }, abstract = {OBJECTIVE: Biofilm formation ability is one of the major virulence factors contributing to the pathogenesis of Candida species. Biofilms produced by Candida spp. cause complicated treatments and contribute to increasing unpleasant mortality rates. Nanoparticles of Fe3O4 (Fe3O4-NPs) are considered due to their magnetic and biochemical properties, as well as their low costs. The purpose of present study was to determine biofilm formation ability in different Candida strains and evaluation of anti-biofilm effect of Fe3O4-NPs compared with FLC.

MATERIALS AND METHODS: In this study, the biofilm-forming ability of Candida strains and the inhibitory effects of Fe3O4-NPs on Candida strains biofilms compared with FLC were measured by MTT assay.

RESULTS: Our finding showed that the biofilm formation ability of C. lusitaniae was significantly higher than other tested Candida strains. However, all the studied Candida strains produced high degree of biofilms. The biofilm formation in different Candida strains was inhibited at concentrations ≥1000μg/mL to ≥4000μg/mL for Fe3O4-NPs and ≥512μg/mL to ≥2048μg/mL for FLC. After exposure to various concentrations of Fe3O4-NPs, biofilm formation reduction in C. albicans and C. parapsilosis were more than FLC. Although, this reduction was not significant. A significant reduction (P<0.05) was observed in biofilm formation in presence of FLC compared with Fe3O4-NPs in C. krusei, C. tropicalis, and C. lusitaniae. The inhibitory effects of Fe3O4-NPs and FLC on biofilm formation of C. glabrata were approximately equal.

CONCLUSION: In accordance with the findings, the biofilm reduction effect of FLC for C. krusei, C. tropicalis, and C. lusitaniae were statistically higher than Fe3O4-NPs.}, } @article {pmid29519520, year = {2018}, author = {Boukahil, I and Czuprynski, CJ}, title = {Mutual antagonism between Mannheimia haemolytica and Pasteurella multocida when forming a biofilm on bovine bronchial epithelial cells in vitro.}, journal = {Veterinary microbiology}, volume = {216}, number = {}, pages = {218-222}, doi = {10.1016/j.vetmic.2018.02.015}, pmid = {29519520}, issn = {1873-2542}, mesh = {Animals ; *Antibiosis ; Biofilms/*growth & development ; Bronchi/cytology/microbiology ; Cattle ; Epithelial Cells/*microbiology ; Mannheimia haemolytica/*physiology ; Pasteurella multocida/*physiology ; }, abstract = {Mannheimia haemolytica and Pasteurella multocida are two bacterial species implicated in the bovine respiratory disease complex (BRDC) that is costly to the beef and dairy cattle industries. Both bacterial species are thought to occupy a similar niche as commensals in the upper respiratory tract. Many bacteria are thought to exist as biofilms in their hosts, perhaps in close proximity with other bacterial species. We previously showed that M. haemolytica forms biofilm on bovine respiratory epithelial cells in vitro. We are interested in the possibility that M. haemolytica and P. multocida co-exist as biofilms in the upper respiratory tract of cattle. In this study, we begin to explore this possibility by assessing the ability of M. haemolytica and P. multocida to form a biofilm on bovine respiratory epithelial cells in vitro. We found that M. haemolytica and P. multocida are separately able to form biofilms on bovine respiratory epithelial cells, but mutually inhibit one another when incubated together as a biofilm. Both the biofilm matrix (crystal violet stain) and bacterial numbers (CFU and PCR) were reduced when M. haemolytica and P. multocida were incubated together on fixed epithelial cells. This inhibition does not appear to result from a soluble factor, as neither conditioned medium nor separation of the two species by a transwell filter membrane reproduced the effect. We infer that when located in close proximity on the epithelial surface, M. haemolytica and P. multocida mutually regulate one another.}, } @article {pmid29518654, year = {2018}, author = {Zhou, H and Wang, G and Wu, M and Xu, W and Zhang, X and Liu, L}, title = {Phenol removal performance and microbial community shift during pH shock in a moving bed biofilm reactor (MBBR).}, journal = {Journal of hazardous materials}, volume = {351}, number = {}, pages = {71-79}, doi = {10.1016/j.jhazmat.2018.02.055}, pmid = {29518654}, issn = {1873-3336}, mesh = {Bacteria/genetics/metabolism ; Biological Oxygen Demand Analysis ; *Bioreactors ; Catechol 1,2-Dioxygenase/metabolism ; Fungi/genetics/metabolism ; Hydrogen-Ion Concentration ; Microbiota ; Phenol/*metabolism ; RNA, Ribosomal, 16S ; Water Pollutants, Chemical/*metabolism ; }, abstract = {A moving bed biofilm reactor (MBBR) effectively removes pollutants and even runs under extreme conditions. However, the pH shock resistance of a biofilm in MBBRs has been rarely reported. In this study, simulated phenol wastewater with acidic shock (pH 7.5-3.0) was used. In the pH shock phase, the phenol and COD removal efficiencies initially decreased and gradually increased to more than 90%. Microscopic studies showed that the superficial biofilm was mainly composed of fungi (yeasts) in the acidic pH shock phase. The microbial community composition in the acidic pH shock phase was significantly different from those in other phases. Firmicutes and Ascomycota were the dominant bacterial and fungal phyla in this stage, respectively. 16S rRNA gene-based functional annotation indicated that functional profiles related to aromatic compound degradation existed in all of the stages. Therefore, MBBRs show potential for the treatment of phenolic wastewater exposed to pH shock.}, } @article {pmid29518324, year = {2018}, author = {Segev-Zarko, LA and Kapach, G and Josten, M and Klug, YA and Sahl, HG and Shai, Y}, title = {Deficient Lipid A Remodeling by the arnB Gene Promotes Biofilm Formation in Antimicrobial Peptide Susceptible Pseudomonas aeruginosa.}, journal = {Biochemistry}, volume = {57}, number = {13}, pages = {2024-2034}, doi = {10.1021/acs.biochem.8b00149}, pmid = {29518324}, issn = {1520-4995}, mesh = {Antimicrobial Cationic Peptides/chemistry/*pharmacology ; *Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; *Lipid A/genetics/metabolism ; *Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Multidrug resistant bacteria possess various mechanisms that can sense environmental stresses such as antibiotics and antimicrobial peptides and rapidly respond to defend themselves. Two known defense strategies are biofilm formation and lipopolysaccharide (LPS) modification. Though LPS modifications are observed in biofilm-embedded bacteria, their effect on biofilm formation is unknown. Using biochemical and biophysical methods coupled with confocal microscopy, atomic force microscopy, and transmission electron microscopy, we show that biofilm formation is promoted in a Pseudomonas aeruginosa PAO1 strain with a loss of function mutation in the arnB gene. This loss of function prevents the addition of the positively charged sugar 4-amino-4-deoxy-l-arabinose to lipid A of LPS under restrictive magnesium conditions. The data reveal that the arnB mutant, which is susceptible to antimicrobial peptides, forms a biofilm that is more robust than that of the wild type. This is in line with the observations that the arnB mutant exhibits outer surface properties such as hydrophobicity and net negative charge that promote the formation of biofilms. Moreover, when grown under Mg[2+] limitation, both the wild type and the arnB mutant exhibited a reduction in the level of membrane-bound polysaccharides. The data suggest that the loss of polysaccharides exposes the membrane and alters its biophysical properties, which in turn leads to more biofilm formation. In summary, we show for the first time that blocking a specific lipid A modification promotes biofilm formation, suggesting a trade-off between LPS remodeling and resistance mechanisms of biofilm formation.}, } @article {pmid29518199, year = {2018}, author = {Di Domenico, EG and Cavallo, I and Guembe, M and Prignano, G and Gallo, MT and Bordignon, V and D'Agosto, G and Sperduti, I and Toma, L and Ensoli, F}, title = {The clinical Biofilm Ring Test: a promising tool for the clinical assessment of biofilm-producing Candida species.}, journal = {FEMS yeast research}, volume = {18}, number = {3}, pages = {}, doi = {10.1093/femsyr/foy025}, pmid = {29518199}, issn = {1567-1364}, mesh = {Biofilms/*growth & development ; Candida/*physiology ; Candidiasis/microbiology ; Clinical Laboratory Techniques/*methods ; Magnetic Phenomena ; Microbiological Techniques ; Microspheres ; Reagent Kits, Diagnostic ; Reproducibility of Results ; }, abstract = {Candida species are opportunistic pathogens responsible for a variety of diseases, ranging from skin and mucosal lesions to severe systemic, life-threatening infections. Candida albicans accounts for more than 70% of all Candida infections, however, the clinical relevance of other species such as Candida parapsilosis and Candida krusei are being increasingly recognized. Biofilm-producing yeasts cells acquire an increased resistance to antifungal agents, often leading to therapeutic failure and chronic infection. Conventional methods such as crystal violet (CV) and tetrazolium (XTT) reduction assay, developed to evaluate biofilm formation in Candida species are usually time-consuming, present a high intra- and inter-assay variability of the results and are therefore hardly applicable to routine diagnostics. This study describes an in-vitro assay developed for the measurement of biofilm formation in Candida species based on the clinical Biofilm Ring Test® (cBRT). We found a significant concordance between the cBRT and both CV (k = 0.74) and XTT (k = 0.62), respectively. Nevertheless, the cBRT resulted more reliable and reproducible than CV and XTT, requiring a minimal sample manipulation and allowing a high throughput assessment, directly on viable cells. The results indicate that the cBRT may provide a suitable, cost-effective technique for routine biofilm testing in clinical microbiology.}, } @article {pmid29517824, year = {2018}, author = {Brilhante, RSN and Correia, EEM and Guedes, GMM and de Oliveira, JS and Castelo-Branco, DSCM and Cordeiro, RA and Pinheiro, AQ and Chaves, LJQ and Pereira Neto, WA and Sidrim, JJC and Rocha, MFG}, title = {In vitro activity of azole derivatives and griseofulvin against planktonic and biofilm growth of clinical isolates of dermatophytes.}, journal = {Mycoses}, volume = {61}, number = {7}, pages = {449-454}, doi = {10.1111/myc.12763}, pmid = {29517824}, issn = {1439-0507}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Arthrodermataceae/*drug effects/growth & development ; Azoles/*pharmacology ; Biofilms/*drug effects/growth & development ; Cat Diseases/microbiology ; Cats ; Dermatomycoses/microbiology/*veterinary ; Dog Diseases/microbiology ; Dogs ; Griseofulvin/*pharmacology ; Humans ; Itraconazole/pharmacology ; Microbial Sensitivity Tests ; Voriconazole/pharmacology ; }, abstract = {As shown by recent research, most of the clinically relevant fungi, including dermatophytes, form biofilms in vitro and in vivo, which may exhibit antimicrobial tolerance that favour recurrent infections. The aim of this study was to determine the minimum inhibitory concentrations (MICs) of itraconazole (ITC), voriconazole (VCZ) and griseofulvin (GRI) against Trichophyton rubrum, Trichophyton tonsurans, Trichophyton mentagrophytes, Microsporum canis and Microsporum gypseum in planktonic and biofilm growth. For the planktonic form, susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI), document M38-A2, while biofilm susceptibility was evaluated using the XTT colorimetric essay. The planktonic growth of all strains was inhibited, with MIC values ranging from 0.00195 to 0.1225 μg/mL for VRC, 0.00195 to 0.25 μg/mL for ITC and <0.0039 to 4 μg/mL for GRI, while a 50-fold increase in the MIC was required to significantly reduce the metabolic activity (P < .05) of dermatophyte biofilms. In brief, the ability of dermatophytes to form biofilms may be a contributing factor for the recalcitrance of dermatophytoses or the dissemination of the disease.}, } @article {pmid29517351, year = {2018}, author = {Jeon, HR and Kwon, MJ and Yoon, KS}, title = {Control of Listeria innocua Biofilms on Food Contact Surfaces with Slightly Acidic Electrolyzed Water and the Risk of Biofilm Cells Transfer to Duck Meat.}, journal = {Journal of food protection}, volume = {81}, number = {4}, pages = {582-592}, doi = {10.4315/0362-028X.JFP-17-373}, pmid = {29517351}, issn = {1944-9097}, mesh = {Acids ; Animals ; *Biofilms ; *Ducks ; Electrolysis ; Food Handling ; Food Microbiology ; Hydrogen-Ion Concentration ; Listeria/drug effects/*physiology ; Red Meat/*microbiology ; Sodium Hypochlorite/pharmacology ; Stainless Steel ; Water ; }, abstract = {Biofilm formation on food contact surfaces is a potential hazard leading to cross-contamination during food processing. We investigated Listeria innocua biofilm formation on various food contact surfaces and compared the washing effect of slightly acidic electrolyzed water (SAEW) at 30, 50, 70, and 120 ppm with that of 200 ppm of sodium hypochlorite (NaClO) on biofilm cells. The risk of L. innocua biofilm transfer and growth on food at retail markets was also investigated. The viability of biofilms that formed on food contact surfaces and then transferred cells to duck meat was confirmed by fluorescence microscopy. L. innocua biofilm formation was greatest on rubber, followed by polypropylene, glass, and stainless steel. Regardless of sanitizer type, washing removed biofilms from polypropylene and stainless steel better than from rubber and glass. Among the various SAEW concentrations, washing with 70 ppm of SAEW for 5 min significantly reduced L. innocua biofilms on food contact surfaces during food processing. Efficiency of transfer of L. innocua biofilm cells was the highest on polypropylene and lowest on stainless steel. The transferred biofilm cells grew to the maximum population density, and the lag time of transferred biofilm cells was longer than that of planktonic cells. The biofilm cells that transferred to duck meat coexisted with live, injured, and dead cells, which indicates that effective washing is essential to remove biofilm on food contact surfaces during food processing to reduce the risk of foodborne disease outbreaks.}, } @article {pmid29516598, year = {2018}, author = {Myrstener, M and Rocher-Ros, G and Burrows, RM and Bergström, AK and Giesler, R and Sponseller, RA}, title = {Persistent nitrogen limitation of stream biofilm communities along climate gradients in the Arctic.}, journal = {Global change biology}, volume = {24}, number = {8}, pages = {3680-3691}, doi = {10.1111/gcb.14117}, pmid = {29516598}, issn = {1365-2486}, mesh = {Arctic Regions ; Biofilms ; Carbon ; *Climate Change ; Ecosystem ; Nitrogen/chemistry/*toxicity ; Rivers/*chemistry ; Soil ; Sweden ; Temperature ; }, abstract = {Climate change is rapidly reshaping Arctic landscapes through shifts in vegetation cover and productivity, soil resource mobilization, and hydrological regimes. The implications of these changes for stream ecosystems and food webs is unclear and will depend largely on microbial biofilm responses to concurrent shifts in temperature, light, and resource supply from land. To study those responses, we used nutrient diffusing substrates to manipulate resource supply to biofilm communities along regional gradients in stream temperature, riparian shading, and dissolved organic carbon (DOC) loading in Arctic Sweden. We found strong nitrogen (N) limitation across this gradient for gross primary production, community respiration and chlorophyll-a accumulation. For unamended biofilms, activity and biomass accrual were not closely related to any single physical or chemical driver across this region. However, the magnitude of biofilm response to N addition was: in tundra streams, biofilm response was constrained by thermal regimes, whereas variation in light availability regulated this response in birch and coniferous forest streams. Furthermore, heterotrophic responses to experimental N addition increased across the region with greater stream water concentrations of DOC relative to inorganic N. Thus, future shifts in resource supply to these ecosystems are likely to interact with other concurrent environmental changes to regulate stream productivity. Indeed, our results suggest that in the absence of increased nutrient inputs, Arctic streams will be less sensitive to future changes in other habitat variables such as temperature and DOC loading.}, } @article {pmid29510413, year = {2018}, author = {Mao, MY and Li, M and Lei, L and Yin, JX and Yang, YM and Hu, T}, title = {The Regulator Gene rnc Is Closely Involved in Biofilm Formation in Streptococcus mutans.}, journal = {Caries research}, volume = {52}, number = {5}, pages = {347-358}, doi = {10.1159/000486431}, pmid = {29510413}, issn = {1421-976X}, mesh = {Biofilms/*growth & development ; Chromatography, Gel ; Genes, Bacterial/genetics/*physiology ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*genetics/growth & development ; }, abstract = {Streptococcus mutans is an important factor in the etiology and pathogenesis of dental caries, largely owing to its ability to form a stable biofilm. Previous animal studies have indicated that rnc could decrease the amount of sulcal caries, and that the downregulation of cariogenicity might be due to its capacity to disrupt biofilm formation. However, the biofunctions by which rnc is involved in biofilm formation remain to be elucidated. In this study, we further investigate the role of rnc based on the study of mature biofilm. Scanning electron microscopy and the crystal violet assay were used to detect the biofilm forming ability. The production and distribution of exopolysaccharides within biofilm was analyzed by exopolysaccharide staining. Gel permeation chromatography was used to perform molecular weight assessment. Its adhesion force was measured by atomic force microscopy. The expression of biofilm formation-associated genes was analyzed at the mRNA level by qPCR. Here, we found that rnc could occur and function in biofilm formation by assembling well-structured, exopolysaccharide-encased, stable biofilms in S. mutans. The weakened biofilm forming ability of rnc-deficient strains was associated with the reduction of exopolysaccharide production and bacterial adhesion. Over all, these data illustrate an interesting situation in which an unappreciated regulatory gene acquired for virulence, rnc, most likely has been coopted as a potential regulator of biofilm formation in S. mutans. Further characterization of rnc may lead to the identification of a possible pathogenic biofilm-specific treatment for dental caries.}, } @article {pmid29509686, year = {2018}, author = {Mystkowska, J and Niemirowicz-Laskowska, K and Łysik, D and Tokajuk, G and Dąbrowski, JR and Bucki, R}, title = {The Role of Oral Cavity Biofilm on Metallic Biomaterial Surface Destruction-Corrosion and Friction Aspects.}, journal = {International journal of molecular sciences}, volume = {19}, number = {3}, pages = {}, pmid = {29509686}, issn = {1422-0067}, mesh = {Biocompatible Materials/*chemistry/standards ; *Biofilms ; Corrosion ; Humans ; Mouth/*microbiology ; *Orthodontic Friction ; }, abstract = {Metallic biomaterials in the oral cavity are exposed to many factors such as saliva, bacterial microflora, food, temperature fluctuations, and mechanical forces. Extreme conditions present in the oral cavity affect biomaterial exploitation and significantly reduce its biofunctionality, limiting the time of exploitation stability. We mainly refer to friction, corrosion, and biocorrosion processes. Saliva plays an important role and is responsible for lubrication and biofilm formation as a transporter of nutrients for microorganisms. The presence of metallic elements in the oral cavity may lead to the formation of electro-galvanic cells and, as a result, may induce corrosion. Transitional microorganisms such as sulfate-reducing bacteria may also be present among the metabolic microflora in the oral cavity, which can induce biological corrosion. Microorganisms that form a biofilm locally change the conditions on the surface of biomaterials and contribute to the intensification of the biocorrosion processes. These processes may enhance allergy to metals, inflammation, or cancer development. On the other hand, the presence of saliva and biofilm may significantly reduce friction and wear on enamel as well as on biomaterials. This work summarizes data on the influence of saliva and oral biofilms on the destruction of metallic biomaterials.}, } @article {pmid29509136, year = {2018}, author = {Araújo, BF and Ferreira, ML and Campos, PA and Royer, S and Gonçalves, IR and da Fonseca Batistão, DW and Fernandes, MR and Cerdeira, LT and Brito, CS and Lincopan, N and Gontijo-Filho, PP and Ribas, RM}, title = {Hypervirulence and biofilm production in KPC-2-producing Klebsiella pneumoniae CG258 isolated in Brazil.}, journal = {Journal of medical microbiology}, volume = {67}, number = {4}, pages = {523-528}, doi = {10.1099/jmm.0.000711}, pmid = {29509136}, issn = {1473-5644}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Brazil ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/*enzymology/genetics/*pathogenicity/physiology ; Microbial Sensitivity Tests ; beta-Lactamases/genetics/*metabolism ; }, abstract = {In this study, we describe the frequency of virulence genes in Klebsiella pneumoniae carbapenemase-2-producing Klebsiella pneumoniae (KPC-KP), including hypervirulent (hv) and hypermucoviscous (hm) strains by whole-genome sequencing. We also evaluate the capacity for biofilm formation by using phenotypic techniques. The occurrence of several virulence genes (fimABCDEFGHIK, mrkABCDFHJ, ecpA, wabG, entB, ugE, irp1, irp2, traT, iutA and ureADE) and a high frequency of hvhmKPC-KP isolates was found. Most hospital-associated lineages of KPC-KP belong to the international clonal group 258 (CG258). Biofilm formation was a constant feature among 90.9 % of KPC-KP strains. This report suggests a close relationship between ST437 and weak biofilm production, given that all weakly biofilm-producing strains belonged to this sequence type. This also supports the dissemination of KPC-KP containing numerous virulence determinants belonging to the biofilm-producing CG258 type in Brazil, including hv and hm strains. These factors allow this pathogen to cause infections, leading to its rapid expansion and persistence in hospital settings.}, } @article {pmid29509112, year = {2018}, author = {Rippon, MG and Rogers, AA and Sellars, L and Styles, KM and Westgate, S}, title = {Effectiveness of a non-medicated wound dressing on attached and biofilm encased bacteria: laboratory and clinical evidence.}, journal = {Journal of wound care}, volume = {27}, number = {3}, pages = {146-155}, doi = {10.12968/jowc.2018.27.3.146}, pmid = {29509112}, issn = {0969-0700}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Cells, Cultured ; Colony Count, Microbial ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Pseudomonas aeruginosa/*drug effects ; Wounds and Injuries/*therapy ; }, abstract = {OBJECTIVE: The objective of this study was to evaluate the ability of a non medicated, hydro-responsive wound dressing (HRWD) to effectively aid in the removal of bacteria known to reside (and cause infections) within the wound environment.

METHOD: A series of in vitro studies were undertaken using Staphylococcus aureus and Pseudomonas aeruginosa biofilms to evaluate the capabilities of the HRWD to disrupt and disperse biofilms.

RESULTS: Biofilms can be broken up and dispersed by HRWD and both Staphylococcus aureus and Pseudomonas aeruginosa numbers can be reduced by a greater than log2 reduction in the presence of HRWD. However, no 'active' agents are released into the wound environment that have an antimicrobial effect.

CONCLUSION: Overall, these studies have shown that this dressing acts as an effective debridement tool, and there are other 'physical' antimicrobial mechanisms impacting bacterial residence. These mechanisms include 1) breaking up and dispersal of biofilms so that the resultant planktonic bacteria are absorbed by the dressing and then 2) sequestered and retained (trapped) within its matrix. Additionally, when PHMB (polyhexamethylene biguanide) is bound within the dressing core but is not released into the wound environment there is the added antimicrobial effect resulting from 3) physical contact with this antiseptic component. Reducing the pathogenicity of the bacteria still further is the dressings ability to 4) absorb and sequester the damaging proteases released by pathogenic bacteria.}, } @article {pmid29506271, year = {2018}, author = {Thieme, L and Klinger-Strobel, M and Hartung, A and Stein, C and Makarewicz, O and Pletz, MW}, title = {In vitro synergism and anti-biofilm activity of ampicillin, gentamicin, ceftaroline and ceftriaxone against Enterococcus faecalis.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {6}, pages = {1553-1561}, doi = {10.1093/jac/dky051}, pmid = {29506271}, issn = {1460-2091}, mesh = {Adult ; Aged ; Aged, 80 and over ; Ampicillin/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ceftriaxone/*pharmacology ; Cephalosporins/*pharmacology ; Cohort Studies ; Drug Synergism ; Endocarditis, Bacterial/drug therapy ; Enterococcus faecalis/*drug effects ; Female ; Gentamicins/*pharmacology ; Gram-Positive Bacterial Infections/drug therapy/microbiology ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; }, abstract = {BACKGROUND: Enterococci frequently cause severe biofilm-associated infections such as endocarditis. The combination of ampicillin/ceftriaxone has recently been clinically evaluated as non-inferior compared with the standard therapy of ampicillin/gentamicin for treatment of Enterococcus faecalis endocarditis. Ceftaroline is a novel cephalosporin with enhanced activity against Gram-positive bacteria.

OBJECTIVES: To compare the in vitro effectiveness of the ceftaroline/ampicillin combination with those of gentamicin/ampicillin and ceftriaxone/ampicillin in planktonic and biofilm cultures of clinical E. faecalis isolates.

METHODS: Synergistic effects at the planktonic level were analysed by chequerboard assays in 20 E. faecalis isolates. Biofilm-eradicating and biofilm-preventing activities of the antibiotics and their combinations were determined by confocal laser scanning microscopy with quantification by quantitative biofilm analysis (qBA) algorithm and cfu/mL determination.

RESULTS: Comparable synergistic effects were observed for both β-lactam combinations in most isolates, in contrast to gentamicin/ampicillin. However, none of the antibiotic combinations succeeded in eradicating mature biofilms. Gentamicin showed promising biofilm-preventing activity, but at concentrations above those clinically tolerable. The β-lactams showed a U-shape dose-response relationship in biofilm prevention. Only exposure to cephalosporins caused alterations in cell morphology, which resulted in cell elongation and reclustering in a concentration-dependent manner. Reclustering was associated with high occurrences of small colony variants (SCVs), especially at high ceftriaxone concentrations.

CONCLUSIONS: This study suggests that combinations of cephalosporins or gentamicin with ampicillin may be advantageous only while bacteraemia persists, whereas combinations have no advantage over monotherapy regarding the treatment of mature biofilms. The selection of SCVs at high ceftriaxone concentrations is worth further study.}, } @article {pmid29506149, year = {2018}, author = {Alav, I and Sutton, JM and Rahman, KM}, title = {Role of bacterial efflux pumps in biofilm formation.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {8}, pages = {2003-2020}, doi = {10.1093/jac/dky042}, pmid = {29506149}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*growth & development ; Bacterial Proteins/antagonists & inhibitors/*physiology ; Biofilms/*growth & development ; *Drug Resistance, Multiple, Bacterial ; Membrane Transport Modulators/pharmacology ; Membrane Transport Proteins/*physiology ; Quorum Sensing ; }, abstract = {Efflux pumps are widely implicated in antibiotic resistance because they can extrude the majority of clinically relevant antibiotics from within cells to the extracellular environment. However, there is increasing evidence from many studies to suggest that the pumps also play a role in biofilm formation. These studies have involved investigating the effects of efflux pump gene mutagenesis and efflux pump inhibitors on biofilm formation, and measuring the levels of efflux pump gene expression in biofilms. In particular, several key pathogenic species associated with increasing multidrug resistance, such as Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, have been investigated, whilst other studies have focused on Salmonella enterica serovar Typhimurium as a model organism and problematic pathogen. Studies have shown that efflux pumps, including AcrAB-TolC of E. coli, MexAB-OprM of P. aeruginosa, AdeFGH of A. baumannii and AcrD of S. enterica, play important roles in biofilm formation. The substrates for such pumps, and whether changes in their efflux activity affect biofilm formation directly or indirectly, remain to be determined. By understanding the roles that efflux pumps play in biofilm formation, novel therapeutic strategies can be developed to inhibit their function, to help disrupt biofilms and improve the treatment of infections. This review will discuss and evaluate the evidence for the roles of efflux pumps in biofilm formation and the potential approaches to overcome the increasing problem of biofilm-based infections.}, } @article {pmid29506074, year = {2018}, author = {Geller, BL and Li, L and Martinez, F and Sully, E and Sturge, CR and Daly, SM and Pybus, C and Greenberg, DE}, title = {Morpholino oligomers tested in vitro, in biofilm and in vivo against multidrug-resistant Klebsiella pneumoniae.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {73}, number = {6}, pages = {1611-1619}, pmid = {29506074}, issn = {1460-2091}, support = {R21 AI111753/AI/NIAID NIH HHS/United States ; R33 AI111753/AI/NIAID NIH HHS/United States ; T32 AI007520/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Disease Models, Animal ; *Drug Resistance, Multiple, Bacterial ; Female ; Klebsiella Infections/drug therapy ; Klebsiella pneumoniae/*drug effects/genetics ; Lung/drug effects/microbiology ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Morpholinos/chemical synthesis/*pharmacology ; Pneumonia, Bacterial/drug therapy/microbiology ; }, abstract = {BACKGROUND: Klebsiella pneumoniae is an opportunistic pathogen and many strains are multidrug resistant. KPC is one of the most problematic resistance mechanisms, as it confers resistance to most β-lactams, including carbapenems. A promising platform technology for treating infections caused by MDR pathogens is the nucleic acid-like synthetic oligomers that silence bacterial gene expression by an antisense mechanism.

OBJECTIVES: To test a peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) in a mouse model of K. pneumoniae infection.

METHODS: PPMOs were designed to target various essential genes of K. pneumoniae and screened in vitro against a panel of diverse strains. The most potent PPMOs were further tested for their bactericidal effects in broth cultures and in established biofilms. Finally, a PPMO was used to treat mice infected with a KPC-expressing strain.

RESULTS: The most potent PPMOs targeted acpP, rpmB and ftsZ and had MIC75s of 0.5, 4 and 4 μM, respectively. AcpP PPMOs were bactericidal at 1-2 × MIC and reduced viable cells and biofilm mass in established biofilms. In a mouse pneumonia model, therapeutic intranasal treatment with ∼30 mg/kg AcpP PPMO improved survival by 89% and reduced bacterial burden in the lung by ∼3 logs. Survival was proportional to the dose of AcpP PPMO. Delaying treatment by 2, 8 or 24 h post-infection improved survival compared with control groups treated with PBS or scrambled sequence (Scr) PPMOs.

CONCLUSIONS: PPMOs have the potential to be effective therapeutic agents against KPC-expressing, MDR K. pneumoniae.}, } @article {pmid29503644, year = {2018}, author = {Lin, F and Li, C and Chen, Z}, title = {Bacteria-Derived Carbon Dots Inhibit Biofilm Formation of Escherichia coli without Affecting Cell Growth.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {259}, pmid = {29503644}, issn = {1664-302X}, abstract = {Biofilms are deleterious in many biomedical and industrial applications and prevention of their formation has been a pressing challenge. Here, carbon dots, CDs-LP that were easily synthesized from the biomass of Lactobacillus plantarum by one-step hydrothermal carbonization, were demonstrated to prevent biofilm formation of E. coli. CDs-LP did not thwart the growth of E. coli, indicating the anti-biofilm effect was not due to the bactericidal effect. Moreover, CDs-LP did not affect the growth of the animal cell AT II, showing low cytotoxicity, good safety and excellent biocompatibility. Therefore, CDs-LP could overcome the cytotoxicity issue found in many current antibiofilm agents. CDs-LP represent a new type of anti-biofilm materials, opening up a novel avenue to the development of biofilm treatment.}, } @article {pmid29501937, year = {2018}, author = {Pirrone, C and Rossi, F and Cappello, S and Borgese, M and Mancini, G and Bernardini, G and Gornati, R}, title = {Evaluation of biomarkers in Mytilus galloprovincialis as an integrated measure of biofilm-membrane bioreactor (BF-MBR) system efficiency in mitigating the impact of oily wastewater discharge to marine environment: a microcosm approach.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {198}, number = {}, pages = {49-62}, doi = {10.1016/j.aquatox.2018.02.018}, pmid = {29501937}, issn = {1879-1514}, mesh = {Animals ; *Biofilms/drug effects ; Biomarkers/*metabolism ; *Bioreactors ; *Ecosystem ; Gills/cytology/drug effects/ultrastructure ; *Membranes, Artificial ; Mytilus/cytology/drug effects/*metabolism/ultrastructure ; Oxidative Stress/drug effects ; RNA, Messenger/genetics/metabolism ; Real-Time Polymerase Chain Reaction ; Wastewater/*analysis ; Water Pollutants, Chemical/toxicity ; }, abstract = {The large volumes of oily wastewater discharged to marine environment cause heavy impacts on the coastal marine ecosystem. The selection of an appropriate technology to reduce these impacts should be based on the respect of the discharge limits and on the effective assessment and monitoring of its effects on biological organism preservation. To this aim, we set up a controlled microcosm-scale system to compare the effects of a treated and untreated oily wastewater discharge in which the restore process is performed through a Membrane Bio-Reactor. The system is completed by other three microcosms to control and isolate any possible concurrent effect on the Mytilus galloprovincialis, used as sentinel organism. Mytilus galloprovincialis have been kept in all these microcosms, and then mRNA expression and morphology were evaluated on gills and digestive gland. The genes considered in this work are Heat Shock Protein 70 and Metallothionein 10, involved in response to physicochemical sublethal stressors, Superoxide dismutase 1, Catalase, and Cytochrome P450 involved in oxidative stress response. Our results evidenced a significant overexpression, both in gills and digestive gland, of HSP70 in samples maintained in the microcosm receiving the untreated effluent, and of MT10 in those animals kept in microcosm where the effluent was treated. Even though the mRNA modifications are considered "primary" and transient responses which do not always correspond to protein content, the study of these modifications can help to gain insights into the mechanisms of action of xenobiotic exposure. Morphological analysis suggested that, although different, depending on the microcosm, the most serious damages were found in the gill epithelium accompanied with severe haemocyte infiltration, whilst in digestive gland the tissue architecture alterations and the haemocyte infiltration were less pronounced. These observations suggest that the immune system was activated as a general response to stressful stimuli such as the presence of toxic compounds. Moreover, the results indicate that the treatment process is useful. In fact, samples derived from the microcosm receiving the treated effluent, even though presenting some signs of stress, seemed to partially recover the normal structure, although their mRNA expression indicated some cellular suffering.}, } @article {pmid29501885, year = {2018}, author = {Kowalski, MS and Devlin, TR and Oleszkiewicz, JA}, title = {Start-up and long-term performance of anammox moving bed biofilm reactor seeded with granular biomass.}, journal = {Chemosphere}, volume = {200}, number = {}, pages = {481-486}, doi = {10.1016/j.chemosphere.2018.02.130}, pmid = {29501885}, issn = {1879-1298}, mesh = {Bacteria/*growth & development ; *Bacterial Physiological Phenomena ; Biodegradation, Environmental ; Biofilms/*growth & development ; Biomass ; Bioreactors/*microbiology ; Oxidation-Reduction ; Quaternary Ammonium Compounds/*chemistry ; Sewage/analysis/*microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/microbiology ; }, abstract = {Availability of granular anammox sludge is much higher than biofilm seed carriers and the sludge is easier to transport. This paper describes and investigates a formation of mature anammox biofilm originated from granular sludge and proves that an anammox moving bed biofilm reactors (MBBR) can be easily and quickly started-up by seeding with granular sludge. The reactor was fed with synthetic wastewater containing ammonium and nitrite. Successful start-up was completed in as little as 50 days when TN removal increased to more than 80%. Surface nitrogen loading rate during start-up was equal to 0.75 g m[-2] d and was stepwise increased up to 5.3 g m[-2] d. Biofilm thickness reached 1269 ± 444 μm at the end of the study with specific anammox activity of 22.0 ± 2.1 mg N g[-1] VSS h. This study shows that granular biomass can be transitioned to a biofilm relatively easily which opens a new window of opportunity for starting-up anammox MBBRs.}, } @article {pmid29500992, year = {2018}, author = {Zhang, J and Huang, J and Say, C and Dorit, RL and Queeney, KT}, title = {Deconvoluting the effects of surface chemistry and nanoscale topography: Pseudomonas aeruginosa biofilm nucleation on Si-based substrates.}, journal = {Journal of colloid and interface science}, volume = {519}, number = {}, pages = {203-213}, doi = {10.1016/j.jcis.2018.02.068}, pmid = {29500992}, issn = {1095-7103}, mesh = {Bacterial Adhesion/*drug effects ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Nanostructures/*chemistry ; Pseudomonas aeruginosa/*physiology ; Silicon/*chemistry ; Surface Properties ; }, abstract = {HYPOTHESIS: The nucleation of biofilms is known to be affected by both the chemistry and topography of the underlying substrate, particularly when topography includes nanoscale (<100 nm) features. However, determining the role of topography vs. chemistry is complicated by concomitant variation in both as a result of typical surface modification techniques. Analyzing the behavior of biofilm-forming bacteria exposed to surfaces with systematic, independent variation of both topography and surface chemistry should allow differentiation of the two effects.

EXPERIMENTS: Silicon surfaces with reproducible nanotopography were created by anisotropic etching in deoxygenated water. Surface chemistry was varied independently to create hydrophilic (OH-terminated) and hydrophobic (alkyl-terminated) surfaces. The attachment and proliferation of Psuedomonas aeruginosa to these surfaces was characterized over a period of 12 h using fluorescence and confocal microscopy.

FINDINGS: The number of attached bacteria as well as the structural characteristics of the nucleating biofilm were influenced by both surface nanotopography and surface chemistry. In general terms, the presence of both nanoscale features and hydrophobic surface chemistry enhance bacterial attachment and colonization. However, the structural details of the resulting biofilms suggest that surface chemistry and topography interact differently on each of the four surface types we studied.}, } @article {pmid29500260, year = {2018}, author = {Zhang, P and Guo, JS and Yan, P and Chen, YP and Wang, W and Dai, YZ and Fang, F and Wang, GX and Shen, Y}, title = {Dynamic Dispersal of Surface Layer Biofilm Induced by Nanosized TiO2 Based on Surface Plasmon Resonance and Waveguide.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {9}, pages = {}, pmid = {29500260}, issn = {1098-5336}, mesh = {Bacillus subtilis/*drug effects/*physiology ; Bacterial Adhesion ; Biofilms/*drug effects ; Extracellular Polymeric Substance Matrix/physiology ; Hydrophobic and Hydrophilic Interactions ; Metal Nanoparticles/*analysis ; Surface Plasmon Resonance ; Surface Properties ; Titanium/*analysis ; }, abstract = {Pollutant degradation is present mainly in the surface layer of biofilms, and the surface layer is the most vulnerable to impairment by toxic pollutants. In this work, the effects of nanosized TiO2 (n-TiO2) on the average thicknesses of Bacillus subtilis biofilm and on bacterial attachment on different surfaces were investigated. The binding mechanism of n-TiO2 to the cell surface was also probed. The results revealed that n-TiO2 caused biofilm dispersal and the thicknesses decreased by 2.0 to 2.6 μm after several hours of exposure. The attachment abilities of bacteria with extracellular polymeric substances (EPS) on hydrophilic surfaces were significantly reduced by 31% and 81% under 10 and 100 mg/liter of n-TiO2, respectively, whereas those of bacteria without EPS were significantly reduced by 43% and 87%, respectively. The attachment abilities of bacteria with and without EPS on hydrophobic surfaces were significantly reduced by 50% and 56%, respectively, under 100 mg/liter of n-TiO2 The results demonstrated that biofilm dispersal can be attributed to the changes in the cell surface structure and the reduction of microbial attachment ability.IMPORTANCE Nanoparticles can penetrate into the outer layer of biofilm in a relatively short period and can bind onto EPS and bacterial surfaces. The current work probed the effects of nanosized TiO2 (n-TiO2) on biofilm thickness, bacterial migration, and surface properties of the cell in the early stage using the surface plasmon resonance waveguide mode. The results demonstrated that n-TiO2 decreased the adhesive ability of both cell and EPS and induced bacterial migration and biofilm detachment in several hours. The decreased adhesive ability of microbes and EPS worked against microbial aggregation, reducing the effluent quality in the biological wastewater treatment process.}, } @article {pmid29498309, year = {2018}, author = {Munaweera, I and Shaikh, S and Maples, D and Nigatu, AS and Sethuraman, SN and Ranjan, A and Greenberg, DE and Chopra, R}, title = {Temperature-sensitive liposomal ciprofloxacin for the treatment of biofilm on infected metal implants using alternating magnetic fields.}, journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group}, volume = {34}, number = {2}, pages = {189-200}, pmid = {29498309}, issn = {1464-5157}, support = {R01 CA199937/CA/NCI NIH HHS/United States ; S10 OD020103/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Biofilms ; Ciprofloxacin/pharmacology/*therapeutic use ; Humans ; Liposomes/*metabolism ; Magnetic Fields ; Microscopy, Electron, Scanning ; }, abstract = {Implants are commonly used as a replacement for damaged tissue. Many implants, such as pacemakers, chronic electrode implants, bone screws, and prosthetic joints, are made of or contain metal. Infections are one of the difficult to treat complications associated with metal implants due to the formation of biofilm, a thick aggregate of extracellular polymeric substances (EPS) produced by the bacteria. In this study, we treated a metal prosthesis infection model using a combination of ciprofloxacin-loaded temperature-sensitive liposomes (TSL) and alternating magnetic fields (AMF). AMF heating is used to disrupt the biofilm and release the ciprofloxacin-loaded TSL. The three main objectives of this study were to (1) investigate low- and high-temperature-sensitive liposomes (LTSLs and HTSLs) containing the antimicrobial agent ciprofloxacin for temperature-mediated antibiotic release, (2) characterise in vitro ciprofloxacin release and stability and (3) study the efficacy of combining liposomal ciprofloxacin with AMF against Pseudomonas aeruginosa biofilms grown on metal washers. The release of ciprofloxacin from LTSL and HTSL was assessed in physiological buffers. Results demonstrated a lower transition temperature for both LTSL and HTSL formulations when incubated in serum as compared with PBS, with a more pronounced impact on the HTSLs. Upon combining AMF with temperature-sensitive liposomal ciprofloxacin, a 3 log reduction in CFU of Pseudomonas aeruginosa in biofilm was observed. Our initial studies suggest that AMF exposure on metal implants can trigger release of antibiotic from temperature sensitive liposomes for a potent bactericidal effect on biofilm.}, } @article {pmid29497413, year = {2018}, author = {Falcone, M and Ferrara, S and Rossi, E and Johansen, HK and Molin, S and Bertoni, G}, title = {The Small RNA ErsA of Pseudomonas aeruginosa Contributes to Biofilm Development and Motility through Post-transcriptional Modulation of AmrZ.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {238}, pmid = {29497413}, issn = {1664-302X}, abstract = {The small RNA ErsA of Pseudomonas aeruginosa was previously suggested to be involved in biofilm formation via negative post-transcriptional regulation of the algC gene that encodes the virulence-associated enzyme AlgC, which provides sugar precursors for the synthesis of several polysaccharides. In this study, we show that a knock-out ersA mutant strain forms a flat and uniform biofilm, not characterized by mushroom-multicellular structures typical of a mature biofilm. Conversely, the knock-out mutant strain showed enhanced swarming and twitching motilities. To assess the influence of ErsA on the P. aeruginosa transcriptome, we performed RNA-seq experiments comparing the knock-out mutant with the wild-type. More than 160 genes were found differentially expressed in the knock-out mutant. Parts of these genes, important for biofilm formation and motility regulation, are known to belong also to the AmrZ transcriptional regulator regulon. Here, we show that ErsA binds in vitro and positively regulates amrZ mRNA at post-transcriptional level in vivo suggesting an interesting contribution of the ErsA-amrZ mRNA interaction in biofilm development at several regulatory levels.}, } @article {pmid29497410, year = {2018}, author = {Vaishampayan, A and de Jong, A and Wight, DJ and Kok, J and Grohmann, E}, title = {A Novel Antimicrobial Coating Represses Biofilm and Virulence-Related Genes in Methicillin-Resistant Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {221}, pmid = {29497410}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has become an important cause of hospital-acquired infections worldwide. It is one of the most threatening pathogens due to its multi-drug resistance and strong biofilm-forming capacity. Thus, there is an urgent need for novel alternative strategies to combat bacterial infections. Recently, we demonstrated that a novel antimicrobial surface coating, AGXX[®], consisting of micro-galvanic elements of the two noble metals, silver and ruthenium, surface-conditioned with ascorbic acid, efficiently inhibits MRSA growth. In this study, we demonstrated that the antimicrobial coating caused a significant reduction in biofilm formation (46%) of the clinical MRSA isolate, S. aureus 04-02981. To understand the molecular mechanism of the antimicrobial coating, we exposed S. aureus 04-02981 for different time-periods to the coating and investigated its molecular response via next-generation RNA-sequencing. A conventional antimicrobial silver coating served as a control. RNA-sequencing demonstrated down-regulation of many biofilm-associated genes and of genes related to virulence of S. aureus. The antimicrobial substance also down-regulated the two-component quorum-sensing system agr suggesting that it might interfere with quorum-sensing while diminishing biofilm formation in S. aureus 04-02981.}, } @article {pmid29494884, year = {2018}, author = {Chen, M and Zhou, X and Liu, X and Zeng, RJ and Zhang, F and Ye, J and Zhou, S}, title = {Facilitated extracellular electron transfer of Geobacter sulfurreducens biofilm with in situ formed gold nanoparticles.}, journal = {Biosensors & bioelectronics}, volume = {108}, number = {}, pages = {20-26}, doi = {10.1016/j.bios.2018.02.030}, pmid = {29494884}, issn = {1873-4235}, mesh = {Acetates/chemistry ; Bioelectric Energy Sources ; Biofilms/*growth & development ; Electric Conductivity ; Electrochemical Techniques ; Electrodes ; Electron Transport ; Extracellular Space/*chemistry ; Geobacter/*physiology ; Gold/*chemistry ; Metal Nanoparticles/*chemistry ; }, abstract = {The conductivity of a biofilm is the key factor for the high current density of a bioelectrochemical system (BES). Most previous works have focused on electrode modification, but, this only benefits the microorganisms that directly contact the electrode. The low conductivity of biofilm limits the current density of the BES. In this work, gold nanoparticles (Au-NPs) were successfully fabricated in situ into a Geobacter sulfurreducens biofilm to increase the conductivity. 20 ppm NaAuCl4 (the precursor) was slowly dropped into the anode chamber at a rate of 1.3 mL/h in a continuous-flow three-electrode BES. The Au(III) was transformed to Au-NPs, which then precipitated in the biofilm via biological mineralization. The current density of the anode increased by 40%. Meanwhile, the removal percentage of the organic substrate (acetate) was enhanced 2.2 times, from 24.7% to 53.3%, after the in situ fabrication of Au-NPs. This method greatly lowered the charge transfer resistance of the anode and enhanced the anodic limiting current. Our results proved that the current density and organic removal rate of the G. sulfurreducens biofilm in the anode were effectively enhanced by in situ Au-NP fabrication. This work not only provides a simple and effective strategy for enhancing the electricity generation of BES with conductive NP fabrication, but also improves the understanding of the extracellular electron transfer (EET) of exoelectrogens.}, } @article {pmid29493309, year = {2018}, author = {Parnham, A and Bousfield, C}, title = {The influence of matrix metalloproteases and biofilm on chronic wound healing: a discussion.}, journal = {British journal of community nursing}, volume = {23}, number = {Sup3}, pages = {S22-S29}, doi = {10.12968/bjcn.2018.23.Sup3.S22}, pmid = {29493309}, issn = {1462-4753}, mesh = {*Biofilms ; Chronic Disease ; Humans ; Matrix Metalloproteinases/*physiology ; Wound Healing/immunology/*physiology ; Wounds and Injuries/*enzymology/*microbiology/*nursing ; }, abstract = {Chronicity in wound healing is a challenge for health services financially and scientifically, with negative consequences on patients' lives. This paper seeks to explore why chronic wounds fail to heal in relation to the inflammatory cellular dysfunction associated with biofilm development. Findings demonstrate an association between chronic wounds failing to heal, the presence of devitalised tissue and abnormal immune cell activity with a consequential excessive release of harmful matrix metalloproteases (MMPs). This process perpetuates the cycle of wound chronicity and extracellular matrix destruction, which prolongs the inflammatory response, fuelling biofilm formation. Evidence suggests that 'trapping' MMPs may increase new tissue growth but, while devitalised tissue is present, phagocytic cells continue to secrete MMPs and chronicity persists. Consequently, by removing the trigger and implementing effective, sustained debridement of devitalised tissue, both MMP and biofilm production will be diminished, with positive healing outcomes.}, } @article {pmid29491853, year = {2018}, author = {Daebeler, A and Herbold, CW and Vierheilig, J and Sedlacek, CJ and Pjevac, P and Albertsen, M and Kirkegaard, RH and de la Torre, JR and Daims, H and Wagner, M}, title = {Cultivation and Genomic Analysis of "Candidatus Nitrosocaldus islandicus," an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {193}, pmid = {29491853}, issn = {1664-302X}, support = {294343/ERC_/European Research Council/International ; }, abstract = {Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as "Candidatus Nitrosocaldus islandicus," is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. "Ca. N. islandicus" encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as "Ca. N. islandicus" is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that "Ca. N. islandicus" has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes - one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and other AOA.}, } @article {pmid29489935, year = {2018}, author = {Zhang, W and Deng, X and Zhou, X and Hao, Y and Li, Y}, title = {Influence of Helicobacter pylori culture supernatant on the ecological balance of a dual-species oral biofilm.}, journal = {Journal of applied oral science : revista FOB}, volume = {26}, number = {}, pages = {e20170113}, pmid = {29489935}, issn = {1678-7765}, mesh = {*Biofilms ; Colony Count, Microbial ; Dental Caries/microbiology ; Dental Plaque/*microbiology ; Gene Expression ; Helicobacter pylori/genetics/*physiology ; In Situ Hybridization, Fluorescence ; Microscopy, Confocal ; Plankton/growth & development ; Polysaccharides, Bacterial/metabolism ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/genetics/*physiology ; Streptococcus sanguis/genetics/*physiology ; Time Factors ; }, abstract = {UNLABELLED: Dental caries is a chronic progressive disease occurring in the tooth hard tissue due to multiple factors, in which bacteria are the initial cause. Both Streptococcus mutans and Streptococcus sanguinis are main members of oral biofilm. Helicobacter pylori may also be detected in dental plaque, playing an important role in the development of dental caries.

OBJECTIVE: The aim of this study was to investigate the effect of H. pylori culture supernatant on S. mutans and S. sanguinis dual-species biofilm and to evaluate its potential ability on affecting dental health.

MATERIAL AND METHODS: The effect of H. pylori supernatant on single-species and dual-species biofilm was measured by colony forming units counting and fluorescence in situ hybridization (FISH) assay, respectively. The effect of H. pylori supernatant on S. mutans and S. sanguinis extracellular polysaccharides (EPS) production was measured by both confocal laser scanning microscopy observation and anthrone-sulfuric acid method. The effect of H. pylori supernatant on S. mutans gene expression was measured by quantitative real-time PCR (qRT-PCR) assays.

RESULTS: H. pylori supernatant could inhibit both S. mutans and S. sanguinis biofilm formation and EPS production. S. sanguinis inhibition rate was significantly higher than that of S. mutans. Finally, S. mutans bacteriocin and acidogenicity related genes expression were affected by H. pylori culture supernatant.

CONCLUSION: Our results showed that H. pylori could destroy the balance between S. mutans and S. sanguinis in oral biofilm, creating an advantageous environment for S. mutans, which became the dominant bacteria, promoting the formation and development of dental caries.}, } @article {pmid29489933, year = {2018}, author = {Souza, BM and Fernandes Neto, C and Salomão, PMA and Vasconcelos, LRSM and Andrade, FB and Magalhães, AC}, title = {Analysis of the antimicrobial and anti-caries effects of TiF4 varnish under microcosm biofilm formed on enamel.}, journal = {Journal of applied oral science : revista FOB}, volume = {26}, number = {}, pages = {e20170304}, pmid = {29489933}, issn = {1678-7765}, mesh = {Analysis of Variance ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cariostatic Agents/*pharmacology ; Cattle ; Chlorhexidine/pharmacology ; Colony Count, Microbial ; Dental Caries/prevention & control ; Dental Enamel/drug effects/*microbiology ; Fluorides/*pharmacology ; Humans ; Microbial Viability/drug effects ; Microradiography ; Placebo Effect ; Random Allocation ; Reproducibility of Results ; Saliva/microbiology ; Sodium Fluoride/pharmacology ; Statistics, Nonparametric ; Streptococcus/*drug effects/growth & development ; Titanium/*pharmacology ; }, abstract = {UNLABELLED: Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect.

OBJECTIVES: This study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model.

MATERIAL AND METHODS: A microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography - TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05).

RESULTS: Only chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% μm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% μm).

CONCLUSIONS: TiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.}, } @article {pmid29489350, year = {2018}, author = {Chepkirui, C and Yuyama, KT and Wanga, LA and Decock, C and Matasyoh, JC and Abraham, WR and Stadler, M}, title = {Microporenic Acids A-G, Biofilm Inhibitors, and Antimicrobial Agents from the Basidiomycete Microporus Species.}, journal = {Journal of natural products}, volume = {81}, number = {4}, pages = {778-784}, doi = {10.1021/acs.jnatprod.7b00764}, pmid = {29489350}, issn = {1520-6025}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Basidiomycota/*chemistry ; Biofilms/*drug effects ; Candida albicans/drug effects ; Cell Line ; Cell Line, Tumor ; Gram-Positive Bacteria/drug effects ; HeLa Cells ; Humans ; Kenya ; Mice ; Microbial Sensitivity Tests/methods ; Staphylococcus aureus/drug effects ; }, abstract = {The need for effective compounds to combat antimicrobial resistance and biofilms which play important roles in human infections continues to pose a major health challenge. Seven previously undescribed acyclic diterpenes linked to isocitric acid by an ether linkage, microporenic acids A-G (1-7), were isolated from the cultures of a hitherto undescribed species of the genus Microporus (Polyporales, Basidiomycota) originating from Kenya's Kakamega forest. Microporenic acids D and E (4 and 5) showed antimicrobial activity against a panel of Gram positive bacteria and a yeast, Candida tenuis. Moreover, microporenic acids A and B (1 and 2) demonstrated dose-dependent inhibition of biofilm formation by Staphylococcus aureus. Compound 1 further showed significant activity against Candida albicans and Staphylococcus aureus preformed biofilms.}, } @article {pmid29488972, year = {2018}, author = {Wang, G and Chen, R and Huang, L and Ma, H and Mu, D and Zhao, Q}, title = {Microbial characteristics of landfill leachate disposed by aerobic moving bed biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {3-4}, pages = {1089-1097}, doi = {10.2166/wst.2017.628}, pmid = {29488972}, issn = {0273-1223}, mesh = {Ammonia/analysis/metabolism ; Bacteria/classification/*isolation & purification/metabolism ; Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; *Bioreactors ; Nitrogen/analysis/metabolism ; *Waste Disposal, Fluid ; Water Pollutants/*analysis/metabolism ; }, abstract = {An aerobic moving bed biofilm reactor (MBBR) was applied to treat landfill leachate generated from a domestic waste incineration plant. Pollutant removal efficiency of this reactor under stable operating condition was studied. The biomass, bacteria species, and microbial metabolism in this reactor were investigated. These results showed that the average removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen in the aerobic MBBR achieved 64% and 97% in the optimum conditions, respectively. The three-dimensional fluorescence spectrum revealed that the content of soluble microbial byproducts from extracellular polymeric substances extraction in suspended sludge was much higher than that on biofilm, and the types of pollutants were various in different regions of the reactor. It also indicated that the MBBR system had a stable, rich and regular microorganism community, including large amounts of nitrifying bacteria and denitrifying bacteria. Scanning electron microscopy suggested that biofilm attached to the packing provided a good anoxic-aerobic micro environment system to achieve a high metabolic activity, which favored COD and ammonia removal.}, } @article {pmid29488966, year = {2018}, author = {Cui, YX and Wu, D and Mackey, HR and Chui, HK and Chen, GH}, title = {Application of a moving-bed biofilm reactor for sulfur-oxidizing autotrophic denitrification.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {3-4}, pages = {1027-1034}, doi = {10.2166/wst.2017.617}, pmid = {29488966}, issn = {0273-1223}, mesh = {Autotrophic Processes ; Biofilms ; *Bioreactors ; *Denitrification ; Equipment Design ; Nitrates/metabolism ; Nitrogen/metabolism ; Oxidation-Reduction ; Sewage ; Sulfides/metabolism ; Sulfur/metabolism ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater ; Water Pollutants, Chemical/metabolism ; }, abstract = {Sulfur-oxidizing autotrophic denitrification (SO-AD) was investigated in a laboratory-scale moving-bed biofilm reactor (MBBR) at a sewage temperature of 22 °C. A synthetic wastewater with nitrate, sulfide and thiosulfate was fed into the MBBR. After 20 days' acclimation, the reduced sulfur compounds were completely oxidized and nitrogen removal efficiency achieved up to 82%. The operation proceeded to examine the denitrification by decreasing hydraulic retention time (HRT) from 12 to 4 h in stages. At steady state, this laboratory-scale SO-AD MBBR achieved the nitrogen removal efficiency of 94% at the volumetric loading rate of 0.18 kg N·(mreactor[3]·d)[-1]. The biofilm formation was examined periodically: the attached volatile solids (AVS) gradually increased corresponding to the decrease of HRT and stabilized at about 1,300 mg AVS·Lreactor[-1] at steady state. This study demonstrated that without adding external organic carbon, SO-AD can be successfully applied in moving-bed carriers. The application of SO-AD MBBR has shown the potential for sulfur-containing industrial wastewater treatment, brackish wastewater treatment and the upgrading of the activated sludge system. Moreover, the study provides direct design information for the full-scale MBBR application of the sulfur-cycle based SANI process.}, } @article {pmid29488508, year = {2018}, author = {Shi, C and Yan, C and Sui, Y and Sun, Y and Guo, D and Chen, Y and Jin, T and Peng, X and Ma, L and Xia, X}, title = {Corrigendum: Thymoquinone Inhibits Virulence Related Traits of Cronobacter sakazakii ATCC 29544 and Has Anti-biofilm Formation Potential.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {290}, pmid = {29488508}, issn = {1664-302X}, abstract = {[This corrects the article on p. 2220 in vol. 8, PMID: 29234307.].}, } @article {pmid29487590, year = {2018}, author = {He, L and Dai, K and Wen, X and Ding, L and Cao, S and Huang, X and Wu, R and Zhao, Q and Huang, Y and Yan, Q and Ma, X and Han, X and Wen, Y}, title = {QseC Mediates Osmotic Stress Resistance and Biofilm Formation in Haemophilus parasuis.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {212}, pmid = {29487590}, issn = {1664-302X}, abstract = {Haemophilus parasuis is known as a commensal organism discovered in the upper respiratory tract of swine where the pathogenic bacteria survive in various adverse environmental stress. QseC, a histidine protein kinase of the two-component regulatory systems CheY/QseC, is involved in the environmental adaptation in bacteria. To investigate the role of QseC in coping with the adverse environment stresses and survive in the host, we constructed a qseC mutant of H. parasuis serovar 13 strain (ΔqseC), MY1902. In this study, we found that QseC was involved in stress tolerance of H. parasuis, by the ΔqseC exhibited a decreased resistance to osmotic pressure, oxidative stress, and heat shock. Moreover, the ΔqseC weakened the ability to take up iron and biofilm formation. We also found that the QseC participate in sensing the epinephrine in environment to regulate the density of H. parasuis.}, } @article {pmid29486408, year = {2018}, author = {Kobayashi, T and Hu, Y and Xu, KQ}, title = {Impact of cationic substances on biofilm formation from sieved fine particles of anaerobic granular sludge at high salinity.}, journal = {Bioresource technology}, volume = {257}, number = {}, pages = {69-75}, doi = {10.1016/j.biortech.2018.02.078}, pmid = {29486408}, issn = {1873-2976}, mesh = {Anaerobiosis ; Bacteria, Anaerobic ; *Biofilms ; *Bioreactors ; Salinity ; *Sewage ; Waste Disposal, Fluid ; }, abstract = {This study investigated early stages of biofilm formation from sieved fine particles of anaerobic granules in the presence of various cationic substances using a quartz crystal sensor to improve biofilm formation in the anaerobic treatment of saline wastewater. The biomass attached on the sensor was greatly increased with Ca within the low range (8-16 mM), which was not affected by 50 mM of Na. However, the positive effect of 16 mM of Ca was strongly reduced in the co-presence of Ca and Na when Na concentrations were in the range from 25 to 150 mM because Ca may compete with Na for the limited binding sites in biofilm. The addition of cationic polymer at 150 mM of Na increased biomass adhesion by several folds at only 10-80 mg/L compared to the addition of 16 mM of Ca. Moreover, no methanogenic inhibition was presented below the polymer content of 20 mg/L.}, } @article {pmid29483899, year = {2018}, author = {Farshadzadeh, Z and Taheri, B and Rahimi, S and Shoja, S and Pourhajibagher, M and Haghighi, MA and Bahador, A}, title = {Growth Rate and Biofilm Formation Ability of Clinical and Laboratory-Evolved Colistin-Resistant Strains of Acinetobacter baumannii.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {153}, pmid = {29483899}, issn = {1664-302X}, abstract = {Two different mechanisms of resistance to colistin in Acinetobacter baumannii have been described. The first involves the total loss of lipopolysaccharide (LPS) due to mutations in the lpxACD operon, which is involved in the lipid A biosynthesis pathway. The second entails the addition of ethanolamine to the lipid A of the LPS resulting from mutations in the PmrAB two-component system. To evaluate the impact of colistin resistance-associated mutations on antimicrobial resistance and virulence properties, four pairs of clinical and laboratory-evolved colistin-susceptible/colistin-resistant (Col[S]/Col[R]) A. baumannii isolates were used. Antimicrobial susceptibility, surface motility, in vitro and in vivo biofilm-forming capacity, in vitro and in vivo expression levels of biofilm-associated genes, and in vitro growth rate were analyzed in these strains. Growth rate, in vitro and in vivo biofilm formation ability, as well as expression levels of biofilm-associated gene were reduced in Col[R] LPS-deficient isolate (the lpxD mutant) when compared with its Col[S] partner, whereas there were not such differences between LPS-modified isolates (the pmrB mutants) and their parental isolates. Mutation in lpxD was accompanied by a greater reduction in minimum inhibitory concentrations of azithromycin, vancomycin, and rifampin than mutation in pmrB. Besides, loss of LPS was associated with a significant reduction in surface motility without any change in expression of type IV pili. Collectively, colistin resistance through loss of LPS causes a more considerable cost in biological features such as growth rate, motility, and biofilm formation capacity relative to LPS modification. Therefore, Col[R] LPS-modified strains are more likely to spread and transmit from one patient to another in hospital settings, which results in more complex treatment and control.}, } @article {pmid29482361, year = {2018}, author = {Parai, D and Banerjee, M and Dey, P and Chakraborty, A and Islam, E and Mukherjee, SK}, title = {Effect of reserpine on Pseudomonas aeruginosa quorum sensing mediated virulence factors and biofilm formation.}, journal = {Biofouling}, volume = {34}, number = {3}, pages = {320-334}, doi = {10.1080/08927014.2018.1437910}, pmid = {29482361}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*drug effects ; Biofilms/growth & development ; Glycolipids ; Ligases/drug effects ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/metabolism/physiology ; Quorum Sensing/*drug effects ; Reserpine/*pharmacology ; Virulence Factors ; }, abstract = {This study aimed to evaluate the effect of reserpine, a plant-derived indole-alkaloid, against Pseudomonas aeruginosa PAO1 biofilms. The anti-biofilm activity of reserpine was evaluated by crystal violet staining, MTT assay, confocal laser scanning microscopy and scanning electron microscopy. Reserpine effects were also assessed by qRT-PCR of quorum sensing (QS)-regulated genes and biochemical quantification of the QS-mediated virulence factors pyocyanin, rhamnolipids, proteases and elastases. Reserpine reduced biofilm formation, cell motility, virulence factor production, and QS-controlled gene expression. Additionally, molecular docking analysis for AHL synthase LasI and QS transcriptional regulators LasR/MvfR revealed a plausible molecular mechanisms of reserpine QS inhibition. These findings provide insights into the underlying mode of action of reserpine, which may be useful in the development of new drugs against biofilm-related infections.}, } @article {pmid29482049, year = {2018}, author = {Thurnheer, T and Belibasakis, GN}, title = {Effect of sodium fluoride on oral biofilm microbiota and enamel demineralization.}, journal = {Archives of oral biology}, volume = {89}, number = {}, pages = {77-83}, doi = {10.1016/j.archoralbio.2018.02.010}, pmid = {29482049}, issn = {1879-1506}, mesh = {Animals ; Anti-Infective Agents/pharmacology ; Bacteria/drug effects/growth & development ; Biofilms/*drug effects ; Cariostatic Agents/pharmacology ; Cattle ; Chlorhexidine/administration & dosage/pharmacology ; Dental Caries/microbiology/prevention & control ; Dental Enamel/*drug effects/microbiology ; Dose-Response Relationship, Drug ; Durapatite ; Fluorides/administration & dosage/pharmacology ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Microbiota/*drug effects ; Mouth/*microbiology ; Mouthwashes/pharmacology ; Phosphates ; Saliva/metabolism ; Sodium Fluoride/administration & dosage/*pharmacology ; Tooth Calcification ; Tooth Demineralization/drug therapy/microbiology/*prevention & control ; Toothpastes/pharmacology ; }, abstract = {OBJECTIVE: Fluoride is widely used as an anti-caries agent, e.g. in toothpastes and mouth rinses. However, the nature of the anti-caries action is not entirely clear. Mechanisms suspected to explain the cariostatic effect include inhibitory effects on acid formation by bacteria, inhibition of extracellular polysaccharide (EPS) production, inhibition of enamel demineralization and enhancement of remineralizaton or combination thereof. The aim of this study was to examine with the supragingival Zurich in vitro biofilm model the effect of fluoride in NaF formulation, on the microbiota and on demineralization.

METHODS: Biofilms consisting of Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, Veillonella dispar and Streptococcus sobrinus, were grown anaerobically on sintered hydroxyapatite or bovine enamel disks, exposed to 200, 400, and 1400 ppm of NaF, or 0.1% chlorhexidine (positive control). The biofilms were harvested after 64 h and CFUs were assessed for total bacteria. Demineralization of enamel disks was measured by quantitative light-induced fluorescence.

RESULTS: NaF did not affect the bacterial numbers. No enamel mineral loss was observed at 1400 and 400 ppm of fluoride, whereas the pH of the surrounding medium was increased to 5.5 and 5.0, respectively, compared to the untreated control (pH 4.5 and mineral loss ΔF of -32%). At 1400 ppm NaF the biofilm's EPS volume was also significantly reduced.

CONCLUSIONS: Administration of NaF completely prevented demineralization without affecting biofilm composition and growth. This protective effect may be attributed to the observed decrease in acid production or EPS volume, or to a shift in the de/remineralization balance.}, } @article {pmid29479978, year = {2018}, author = {Zamani, H and Salehzadeh, A}, title = {Biofilm formation in uropathogenic Escherichia coli: association with adhesion factor genes.}, journal = {Turkish journal of medical sciences}, volume = {48}, number = {1}, pages = {162-167}, doi = {10.3906/sag-1707-3}, pmid = {29479978}, issn = {1300-0144}, mesh = {Bacterial Adhesion/*genetics ; Biofilms/*growth & development ; Escherichia coli Infections/*microbiology ; *Fimbriae, Bacterial ; Humans ; Phenotype ; Urinary Tract Infections/*microbiology ; Uropathogenic Escherichia coli/genetics/*pathogenicity ; Virulence Factors/*genetics ; }, abstract = {Background/aim: Biofilm formation is a major determinant factor in the development of urinary tract infections (UTIs) by uropathogenic Escherichia coli (UPEC). Several adhesion factors are involved in attachment of bacterial cells to the urinary tract and biofilm development. Materials and methods: The possible relationship between different adhesion factor genes (AFGs) and biofilm formation among UPEC isolates was investigated. Prevalence of different AFGs including fimA, fimH, papAH, papC, papEF, sfa-S, foc/G, and bmaE and their association to biofilm formation were investigated. Phenotypic expression of type 1 and P fimbriae was also investigated. Results: Our results showed that 84% of UPEC were moderate to strong biofilm producers. Prevalence of the type 1 and P fimbriae associated genes (fimA, fimH, papEF, papC) as well as the F1C fimbriae gene (foc/G) did not show a difference among different biofilm-producing groups, while higher prevalence of papAH, bmaE (M fimbriae), and sfaS (S-fimbriae) was observed for the strains producing moderate to strong biofilms. Phenotypic expression of type 1 fimbriae was associated with biofilm formation, while no association was observed for P fimbriae. Conclusion: Different AFGs (especially M and S fimbria) and their expression levels affect the biofilm formation ability of UPEC.}, } @article {pmid29478785, year = {2018}, author = {Lee, HS}, title = {Electrokinetic analyses in biofilm anodes: Ohmic conduction of extracellular electron transfer.}, journal = {Bioresource technology}, volume = {256}, number = {}, pages = {509-514}, doi = {10.1016/j.biortech.2018.02.002}, pmid = {29478785}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Electrodes ; Electron Transport ; Electrons ; Geobacter ; }, abstract = {This review explores electron transfer kinetics from an electron donor to the anode in electrically conductive biofilm anodes. Intracellular electron transfer (IET) from the donor to the anode is well described with the Monod equation. In comparison, mechanisms of extracellular electron transfer (EET) conduction are unclear yet, complicating EET kinetics. However, in biofilm anodes where potential gradient to saturated current density is less than ∼300 mV, Ohmic conduction successfully describe conductive EET mainly with biofilm conductivity (Kbio) and biofilm thickness (Lf). High Kbio essential for production of high current density is found in Geobacter pure or enriched biofilm anodes, but other exoelectrogens could make biofilms electrically conductive. IET is rate-limiting for current density in conductive biofilms, and biofilm density of active exoelectrogens and Lf are operating parameters that can be optimized further to improve current density.}, } @article {pmid29478479, year = {2018}, author = {Pugazhendhi, S and Dorairaj, AP}, title = {Appraisal of Biofilm Formation in Diabetic Foot Infections by Comparing Phenotypic Methods With the Ultrastructural Analysis.}, journal = {The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons}, volume = {57}, number = {2}, pages = {309-315}, doi = {10.1053/j.jfas.2017.10.010}, pmid = {29478479}, issn = {1542-2224}, mesh = {Adult ; Aged ; Bacterial Infections/diagnosis/drug therapy/*microbiology ; Bacteriological Techniques ; Biofilms/*growth & development ; Cohort Studies ; Diabetic Foot/*microbiology ; Female ; Humans ; India ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Phenotype ; Pseudomonas aeruginosa/isolation & purification/*ultrastructure ; Retrospective Studies ; Staphylococcal Infections/diagnosis/drug therapy/*epidemiology ; Staphylococcus aureus/isolation & purification/*ultrastructure ; }, abstract = {Diabetic patients are more prone to the development of foot ulcers, because their underlying tissues are exposed to colonization by various pathogenic organisms. Hence, biofilm formation plays a vital role in disease progression by antibiotic resistance to the pathogen found in foot infections. The present study has demonstrated the correlation of biofilm assay with the clinical characteristics of diabetic foot infection. The clinical characteristics such as the ulcer duration, size, nature, and grade were associated with biofilm production. Our results suggest that as the size of the ulcer with poor glycemic control increased, the organism was more likely to be positive for biofilm formation. A high-degree of antibiotic resistance was exhibited by the biofilm-producing gram-positive isolates for erythromycin and gram-negative isolates for cefpodoxime. Comparisons of biofilm production using 3 different conventional methods were performed. The strong producers with the tube adherence method were able to produce biofilm using the cover slip assay method, and the weak producers in tube adherence method had difficulty in producing biofilm using the other 2 methods, indicating that the tube adherence method is the best method for assessing biofilm formation. The strong production of biofilm with the conventional method was further confirmed by scanning electron microscopy analysis, because bacteria attached as a distinct layer of biofilm. Thus, the high degree of antibiotic resistance was exhibited by biofilm producers compared with nonbiofilm producers. The tube adherence and cover slip assay were found to be the better method for biofilm evaluation.}, } @article {pmid29478220, year = {2018}, author = {Dellias, MTF and Borges, CD and Lopes, ML and da Cruz, SH and de Amorim, HV and Tsai, SM}, title = {Biofilm formation and antimicrobial sensitivity of lactobacilli contaminants from sugarcane-based fuel ethanol fermentation.}, journal = {Antonie van Leeuwenhoek}, volume = {111}, number = {9}, pages = {1631-1644}, doi = {10.1007/s10482-018-1050-8}, pmid = {29478220}, issn = {1572-9699}, support = {158347/2010-2//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 153037/2012-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Biofuels/*microbiology ; Brazil ; DNA, Bacterial/genetics ; Ethanol/metabolism ; Fermentation ; Genome, Bacterial ; Lactobacillus/*chemistry/genetics/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Microbial Viability/*drug effects ; RNA, Ribosomal, 16S/genetics ; Saccharum/*metabolism/microbiology ; }, abstract = {Industrial ethanol fermentation is subject to bacterial contamination that causes significant economic losses in ethanol fuel plants. Chronic contamination has been associated with biofilms that are normally more resistant to antimicrobials and cleaning efforts than planktonic cells. In this study, contaminant species of Lactobacillus isolated from biofilms (source of sessile cells) and wine (source of planktonic cells) from industrial and pilot-scale fermentations were compared regarding their ability to form biofilms and their sensitivity to different antimicrobials. Fifty lactobacilli were isolated and the most abundant species were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus plantarum. The majority of the isolates (87.8%) were able to produce biofilms in pure culture. The capability to form biofilms and sensitivity to virginiamycin, monensin and beta-acids from hops, showed inter- and intra-specific variability. In the pilot-scale fermentation, Lactobacillus brevis, L. casei and the majority of L. plantarum isolates were less sensitive to beta-acids than their counterparts from wine; L. brevis isolates from biofilms were also less sensitive to monensin when compared to the wine isolates. Biofilm formation and sensitivity to beta-acids showed a positive and negative correlation for L. casei and L. plantarum, respectively.}, } @article {pmid29477805, year = {2018}, author = {Fernández Ramírez, MD and Nierop Groot, MN and Smid, EJ and Hols, P and Kleerebezem, M and Abee, T}, title = {Role of cell surface composition and lysis in static biofilm formation by Lactobacillus plantarum WCFS1.}, journal = {International journal of food microbiology}, volume = {271}, number = {}, pages = {15-23}, doi = {10.1016/j.ijfoodmicro.2018.02.013}, pmid = {29477805}, issn = {1879-3460}, mesh = {Aminoacyltransferases/*genetics ; Bacterial Adhesion/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cell Membrane/metabolism ; Cell Wall/metabolism ; Cysteine Endopeptidases/*genetics ; Food Handling ; Food Microbiology ; Glycosyltransferases/genetics ; Lactobacillus plantarum/*genetics/*growth & development ; Membrane Proteins/metabolism ; Peptidoglycan/genetics/*metabolism ; }, abstract = {Next to applications in fermentations, Lactobacillus plantarum is recognized as a food spoilage organism, and its dispersal from biofilms in food processing environments might be implicated in contamination or recontamination of food products. This study provides new insights into biofilm development by L. plantarum WCFS1 through comparative analysis of wild type and mutants affected in cell surface composition, including mutants deficient in the production of Sortase A involved in the covalent attachment of 27 predicted surface proteins to the cell wall peptidoglycan (ΔsrtA) and mutants deficient in the production of capsular polysaccharides (CPS1-4, Δcps1-4). Surface adhesion and biofilm formation studies revealed none of the imposed cell surface modifications to affect the initial attachment of cells to polystyrene while biofilm formation based on Crystal Violet (CV) staining was severely reduced in the ΔsrtA mutant and significantly increased in mutants lacking the cps1 cluster, compared to the wild-type strain. Fluorescence microscopy analysis of biofilm samples pointed to a higher presence of extracellular DNA (eDNA) in cps1 mutants and this corresponded with increased autolysis activity. Subsequent studies using Δacm2 and ΔlytA derivatives affected in lytic behaviour revealed reduced biofilm formation measured by CV staining, confirming the relevance of lysis for the build-up of the biofilm matrix with eDNA.}, } @article {pmid29477784, year = {2018}, author = {Yang, LF and Liu, X and Lv, LL and Ma, ZM and Feng, XC and Ma, TH}, title = {Dracorhodin perchlorate inhibits biofilm formation and virulence factors of Candida albicans.}, journal = {Journal de mycologie medicale}, volume = {28}, number = {1}, pages = {36-44}, doi = {10.1016/j.mycmed.2017.12.011}, pmid = {29477784}, issn = {1773-0449}, mesh = {Animals ; Antifungal Agents/administration & dosage/*pharmacology/toxicity ; Benzopyrans/administration & dosage/*pharmacology/toxicity ; Biofilms/*drug effects ; Caenorhabditis elegans/drug effects ; Candida albicans/*drug effects/enzymology/growth & development/pathogenicity ; Cell Line, Tumor ; Humans ; Hyphae/*drug effects ; Microbial Sensitivity Tests ; Phospholipases/drug effects ; Virulence/drug effects ; Virulence Factors ; }, abstract = {OBJECTIVE: The aim of this study was to investigate the antifungal activity of dracorhodin perchlorate (DP) against planktonic growth and virulence factors of Candida albicans.

METHODS: Microdilution method based on CLSI-M27-A3 was used to test the antifungal susceptibility of DP. The activity of DP against biofilm formation and development of C. albicans was quantified by XTT assay and visualized by confocal laser scanning microscope. The effect of DP on the morphological transition of C. albicans induced by four kinds of hyphal-inducing media at 37°C for 4hours was observed under microscope. The rescue experiment by adding exogenous cAMP analog was performed to investigate the involvement of cAMP in the yeast to hyphal transition and biofilm formation of C. albicans. Egg yolk emulsion agar was used to determine the inhibition of DP on the phospholipase production of C. albicans. Human JEG-3 and HUVEC cell lines, as well as the nematode Caenorhabditis elegans was used to assess the toxicity of DP.

RESULTS: The minimum inhibitory concentration (MIC) of DP is 64μM while the antifungal activity was fungistatic. As low as a concentration at 16μM, DP could inhibit the yeast to hyphal transition in liquid RPMI-1640, Spider, GlcNAc and 10% FBS-containing Sabouroud Dextrose medium, as well as on the solid spider agar. Exogenous cAMP analog could rescue part of biofilm viability of C. albicans. DP could inhibit the production of phospholipase. The toxicity of DP against human cells and C. elegans is low.

CONCLUSION: DP could inhibit the planktonic growth and virulent factors in multiple stages, such as yeast to hyphal transition, adhesion, biofilm formation and production of phospholipase of C. albicans.}, } @article {pmid29477536, year = {2018}, author = {Ye, Y and Ling, N and Gao, J and Zhang, X and Zhang, M and Tong, L and Zeng, H and Zhang, J and Wu, Q}, title = {Roles of outer membrane protein W (OmpW) on survival, morphology, and biofilm formation under NaCl stresses in Cronobacter sakazakii.}, journal = {Journal of dairy science}, volume = {101}, number = {5}, pages = {3844-3850}, doi = {10.3168/jds.2017-13791}, pmid = {29477536}, issn = {1525-3198}, mesh = {Bacterial Outer Membrane Proteins/genetics/*metabolism ; *Biofilms ; Cronobacter sakazakii/genetics/growth & development/*physiology/ultrastructure ; Infant Formula/microbiology ; Membrane Proteins/metabolism ; Osmotic Pressure ; Sodium Chloride/*metabolism ; }, abstract = {Cronobacter sakazakii is an important foodborne pathogen associated with rare but severe infections through consumption of powdered infant formula. Tolerance to osmotic stress in Cronobacter has been described. However, the detailed factors involved in tolerance to osmotic stress in C. sakazakii are poorly understood. In this study, roles of outer membrane protein W (OmpW) on survival rates, morphologic changes of cells, and biofilm formation in C. sakazakii under different NaCl concentrations between wild type (WT) and OmpW mutant (ΔOmpW) were determined. The survival rates of ΔOmpW in Luria-Bertani medium with 3.5% or 5.5% NaCl were reduced significantly, and morphological injury of ΔOmpW was significantly increased compared with survival and morphology of WT. Compared with biofilm formation of the WT strain, biofilms in ΔOmpW were significantly increased in Luria-Bertani with 3.5% or 5.5% NaCl using crystal violet staining assay after 48 and 72 h of incubation. Detection of biofilms using confocal laser scanning microscopy and scanning electron microscopy further confirmed the changes of biofilm formation under different NaCl stresses. This study demonstrates that OmpW contributes to survival of cells in planktonic mode under NaCl stresses, and biofilm formation is increased in ΔOmpW in response to NaCl stress.}, } @article {pmid29477120, year = {2018}, author = {Derakhshan, Z and Ehrampoush, MH and Mahvi, AH and Ghaneian, MT and Mazloomi, SM and Faramarzian, M and Dehghani, M and Fallahzadeh, H and Yousefinejad, S and Berizi, E and Bahrami, S}, title = {Biodegradation of atrazine from wastewater using moving bed biofilm reactor under nitrate-reducing conditions: A kinetic study.}, journal = {Journal of environmental management}, volume = {212}, number = {}, pages = {506-513}, doi = {10.1016/j.jenvman.2018.02.043}, pmid = {29477120}, issn = {1095-8630}, mesh = {*Atrazine ; *Biodegradation, Environmental ; Biofilms ; Bioreactors ; Waste Disposal, Fluid ; *Wastewater ; Water Pollutants, Chemical ; *Water Purification ; }, abstract = {In this study employed an anoxic moving bed biofilm reactor (AnMBBR) to evaluate the effects of hydraulic and toxic shocks on performance reactor. The results indicated a relatively good resistance of system against exercised shocks and its ability to return to steady-state conditions. In optimal conditions when there was the maximum rate of atrazine and soluble chemical oxygen demand (COD) removal were 74.82% and 99.29% respectively. Also, atrazine biodegradation rapidly declines in AnMBBR from 74% ± 0.05 in the presence of nitrate to 9.12% only 3 days after the nitrate was eliding from the influent. Coefficients kinetics was studied and the maximum atrazine removal rate was determined by modified Stover & Kincannon model (Umax = 9.87 gATZ/m[3]d). Results showed that AnMBBR is feasible, easy, affordable, so suitable process for efficiently biodegrading toxic chlorinated organic compounds such as atrazine. Also, its removal mechanism in this system is co-metabolism.}, } @article {pmid29476689, year = {2018}, author = {Belmadani, A and Semlali, A and Rouabhia, M}, title = {Dermaseptin-S1 decreases Candida albicans growth, biofilm formation and the expression of hyphal wall protein 1 and aspartic protease genes.}, journal = {Journal of applied microbiology}, volume = {125}, number = {1}, pages = {72-83}, doi = {10.1111/jam.13745}, pmid = {29476689}, issn = {1365-2672}, mesh = {Amphibian Proteins/*pharmacology ; Amphotericin B/pharmacology ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Aspartic Acid Proteases/genetics ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/genetics/growth & development/ultrastructure ; Fungal Proteins/*genetics ; Gene Expression Regulation, Fungal/*drug effects ; Hyphae/drug effects/growth & development ; Virulence/genetics ; }, abstract = {AIMS: This study aimed to investigate the effect of synthetic antimicrobial peptide dermaseptin-S1 (DS1) (ALWKTMLKKLGTMALHAGKAALGAADTISQGTQ) on the growth of Candida albicans, its transition from blastospore to hyphae, and its biofilm formation. We also analysed the expression of different genes (HWP1 and SAPs) involved in C. albicans virulence.

METHODS AND RESULTS: Using cell count we showed that in addition to decreasing C. albicans growth, peptide DS1 inhibited its transition from blastospore to hyphal form. These effects are comparable to those obtained with amphotericin B (AmB). Electron microscopy analyses showed that C. albicans cells treated with either DS1 or AmB displayed a distorted cell wall surface, suggesting that the effect of DS1 was similar to that of AmB on C. albicans cell membrane structure. These observations were confirmed by our results with biofilms showing that both DS1 peptide and AmB significantly inhibited biofilm formation after 2 and 4 days. The effect of DS1 on C. albicans growth, transition and biofilm formation may occur through gene modulation, as the expression of HWP1, SAP1, SAP2, SAP3, SAP9 and SAP10 genes involved in C. albicans pathogenesis were all downregulated when C. albicans was treated with DS1.

CONCLUSIONS: DS1 inhibits the growth and hyphal transition of C. albicans. DS1 was also able to decrease the expression of and gene expression of hyphal wall protein 1 and aspartic proteases genes by C. albicans.

These data provide new insight into the efficacy of DS1 against C. albicans and its potential for use as an antifungal therapy.}, } @article {pmid29473983, year = {2018}, author = {Ramanathan, S and Arunachalam, K and Chandran, S and Selvaraj, R and Shunmugiah, KP and Arumugam, VR}, title = {Biofilm inhibitory efficiency of phytol in combination with cefotaxime against nosocomial pathogen Acinetobacter baumannii.}, journal = {Journal of applied microbiology}, volume = {125}, number = {1}, pages = {56-71}, doi = {10.1111/jam.13741}, pmid = {29473983}, issn = {1365-2672}, mesh = {Acinetobacter baumannii/*drug effects/growth & development/pathogenicity/ultrastructure ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Cefotaxime/*pharmacology ; Cross Infection/*microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/genetics ; Humans ; Phytol/*pharmacology ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {AIMS: This study aimed to evaluate the antibiofilm potential of phytol and cefotaxime combinations (PCCs) against Acinetobacter baumannii and to elucidate the molecular mechanism of their antibiofilm potential through the transcriptomic approach.

METHODS AND RESULTS: Phytol and cefotaxime combination(s) (PCC(s) [160 μg ml[-1]  + 8 μg ml[-1] for microbial type culture collection (MTCC) strain and 160 μg ml[-1]  + 0.5 μg ml[-1] for clinical isolate] effectively inhibited the A. baumannii biofilm formation. Additionally, light, confocal laser scanning and scanning electron microscopic analyses validated the antibiofilm potential of PCCs. Furthermore, PCCs treated A. baumannii cells showed a decreased level of hydrophobicity index compared to their respective controls. Fourier-transform infrared (FT-IR) spectra of exopolysaccharide matrix extracted from PCCs-treated A. baumannii cells showed a visible decrease in absorbance of polysaccharides, nucleic acids and protein regions compared to the spectra of untreated controls. In the blood sensitivity assay, the PCCs-treated A. baumannii plates showed reduced a number of bacterial colonies compared to their control plates. Reduced level of catalase production was also observed in the PCCs treatment compared to their controls. Transcriptomic analysis revealed the downregulation of bfmR, bap, csuA/B, ompA, pgaA, pgaC and katE biofilm virulence genes in both the A. baumannii strains on treatment with PCCs.

CONCLUSION: The obtained results of this study indicate that PCCs have potent antibiofilm activity and downregulate the biofilm-related virulence genes expression in A. baumannii.

To the best of our knowledge, this is the pioneering study, which shows the antibiofilm effect of PCCs against A. baumannii along with their molecular mechanism. The antibiofilm effect of PCCs could be a successful strategy for eradicating infections related to A. baumannii biofilms in nosocomial settings.}, } @article {pmid29472619, year = {2018}, author = {Duraj-Thatte, AM and Praveschotinunt, P and Nash, TR and Ward, FR and Nguyen, PQ and Joshi, NS}, title = {Modulating bacterial and gut mucosal interactions with engineered biofilm matrix proteins.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {3475}, pmid = {29472619}, issn = {2045-2322}, support = {R01 DK110770/DK/NIDDK NIH HHS/United States ; }, mesh = {Bacterial Adhesion/genetics ; Biofilms/growth & development ; Escherichia coli/chemistry/*genetics ; Fimbriae, Bacterial/chemistry/*genetics ; Gene Expression Regulation, Bacterial/genetics ; Host-Pathogen Interactions/*genetics ; Humans ; *Protein Engineering ; }, abstract = {Extracellular appendages play a significant role in mediating communication between bacteria and their host. Curli fibers are a class of bacterial fimbria that is highly amenable to engineering. We demonstrate the use of engineered curli fibers to rationally program interactions between bacteria and components of the mucosal epithelium. Commensal E. coli strains were engineered to produce recombinant curli fibers fused to the trefoil family of human cytokines. Biofilms formed from these strains bound more mucins than those producing wild-type curli fibers, and modulated mucin rheology as well. When treated with bacteria producing the curli-trefoil fusions mammalian cells behaved identically in terms of their migration behavior as when they were treated with the corresponding soluble trefoil factors. Overall, this demonstrates the potential utility of curli fibers as a scaffold for the display of bioactive domains and an untapped approach to rationally modulating host-microbe interactions using bacterial matrix proteins.}, } @article {pmid29471691, year = {2018}, author = {Sharifi, A and Ahmadi, A and Mohammadzadeh, A}, title = {Streptococcus pneumoniae quorum sensing and biofilm formation are affected by Thymus daenensis, Satureja hortensis, and Origanum vulgare essential oils.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {65}, number = {3}, pages = {345-359}, doi = {10.1556/030.65.2018.013}, pmid = {29471691}, issn = {1217-8950}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; Oils, Volatile/chemistry/*pharmacology ; Origanum/*chemistry ; Plant Extracts/chemistry/*pharmacology ; Quorum Sensing/*drug effects ; Satureja/*chemistry ; Streptococcus pneumoniae/*drug effects/physiology ; Thymus Plant/*chemistry ; }, abstract = {The aim of this study was to investigate the effect of Thymus daenensis L., Satureja hortensis L., and Origanum vulgare L. essential oils (EOs) on the planktonic growth, biofilm formation, quorum sensing (QS), and competence system (CS) of Streptococcus pneumoniae. The anti-biofilm activity of EOs was determined by Microtiter-Plate Test (MtP) and scanning electron microscope (SEM). The QS and CS inhibitory activities were determined on the pre-grown biofilm by gene expression analysis using quantitative real-time RT-PCR. Using gas chromatography-mass spectrometry analysis, the major components of the tested EOs were detected. The MtP and SEM detected a significant inhibitory effect of the three EOs on biofilm formation at sub-minimum inhibitory concentrations (MICs). The most anti-biofilm activity was seen for T. daenensis. LuxS and pfs genes (genes involved in QS) downregulated the following treatment with MIC/2 of Thymus and Satureja EOs. Thymol, carvacrol, p-cymene, pulegone, and 1,8-cineole were the major components of the tested EOs. The used EOs seem to be good candidates for preventing biofilm formation and subsequent colonization of S. pneumoniae. This study introduced T. daenensis and S. hortensis as new anti-biofilm and QS inhibitor agents with a natural origin.}, } @article {pmid29471135, year = {2018}, author = {Capote-Bonato, F and Bonato, DV and Ayer, IM and Magalhães, LF and Magalhães, GM and Pereira da Câmara Barros, FF and Teixeira, PPM and Crivellenti, LZ and Negri, M and Svidzinski, TIE}, title = {Murine model for the evaluation of candiduria caused by Candida tropicalis from biofilm.}, journal = {Microbial pathogenesis}, volume = {117}, number = {}, pages = {170-174}, doi = {10.1016/j.micpath.2018.02.036}, pmid = {29471135}, issn = {1096-1208}, mesh = {Animals ; Biofilms/*growth & development ; Candida tropicalis/*pathogenicity ; Candidiasis/immunology/*microbiology/pathology ; Colony Count, Microbial ; Cystotomy/methods ; *Disease Models, Animal ; Female ; Host-Pathogen Interactions/immunology ; Immune Evasion ; Inflammation/microbiology/pathology ; Mice ; Mice, Inbred BALB C ; Time Factors ; Urinary Bladder/microbiology/pathology ; Urinary Catheters/microbiology ; Urinary Tract Infections/immunology/*microbiology/pathology ; }, abstract = {To evaluate the pathophysiology of catheter-associated candiduria, the bladders of female mice were infected with Candida tropicalis. One group was implanted with a catheter fragment with preformed biofilm by cystotomy technique, while another group received, in separate, a sterile catheter fragment and a correspondent yeast suspension. The bladder tissues were examined by histopathology and the quantity of colony forming units was evaluated. All the animals presented inflammation and the presence of C. tropicalis was observed in the tissue within 72 h of the introduction of biofilm, while 75% of the mice remained infected after 144 h. However, only 50% of animals from the group infected with C. tropicalis in suspension (planktonic yeasts), exhibited such signs of infection over time. The cystotomy technique is therefore viable in mice, and is an effective model for evaluating the pathogenesis of candiduria from catheter biofilms. The model revealed the potential of C. tropicalis infectivity and demonstrated more effective evasion of the host response in biofilm form than the planktonic yeast.}, } @article {pmid29469615, year = {2018}, author = {Misba, L and Khan, AU}, title = {Enhanced photodynamic therapy using light fractionation against Streptococcus mutans biofilm: type I and type II mechanism.}, journal = {Future microbiology}, volume = {13}, number = {}, pages = {437-454}, doi = {10.2217/fmb-2017-0207}, pmid = {29469615}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Dental Caries/*microbiology ; Dose Fractionation, Radiation ; Gene Expression Regulation, Bacterial/drug effects ; HEK293 Cells ; Humans ; *Light ; Microbial Viability/drug effects ; Photosensitizing Agents/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Reactive Oxygen Species/classification/metabolism ; Streptococcus mutans/*drug effects/genetics/physiology ; }, abstract = {AIM: The objective of the study was to look the efficacy of fractionated light against Streptococcus mutans biofilm.

MATERIALS & METHODS: Antibiofilm assays (crystal violet, congo red), electron microscopic, confocal and spectroscopic studies were performed to check the effect of fractionated light.

RESULTS: 6-6.5 log10 reduction of planktonic and 3.6-4.2 log10 reduction in biofilm were observed after irradiation with fractionated as compared with continuous light. Increased permeability to propidium iodide and leakage of cellular constituent validate the greater antibiofilm effect of fractionated light. Spectroscopic studies confirmed the relative contribution of type I and type II photochemistry.

CONCLUSION: Phenothiazinium dyes have a potential against bacterial biofilm in combination with light fractionation and it offers new opportunities to explore its clinical implication.}, } @article {pmid29469610, year = {2018}, author = {Freitas, AI and Lopes, N and Oliveira, F and Brás, S and França, Â and Vasconcelos, C and Vilanova, M and Cerca, N}, title = {Comparative analysis between biofilm formation and gene expression in Staphylococcus epidermidis isolates.}, journal = {Future microbiology}, volume = {13}, number = {}, pages = {415-427}, doi = {10.2217/fmb-2017-0140}, pmid = {29469610}, issn = {1746-0921}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Gene Expression/*genetics ; Humans ; Polysaccharides, Bacterial/metabolism ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/*genetics/growth & development/isolation & purification/*physiology ; Time Factors ; Transcription, Genetic ; }, abstract = {AIM: To understand the relationship between ica, aap and bhp gene expression and the implications in biofilm formation in selected clinical and commensal Staphylococcus epidermidis isolates.

MATERIAL & METHODS: Isolates were analyzed regarding their biofilm-forming capacity, biochemical matrix composition, biofilm spatial organization and expression of biofilm-related genes.

RESULTS: On polysaccharide intercellular adhesin-dependent biofilms, aap and bhp contributions for the biofilm growth were negligible, despite very high levels of expression. In contrast, smaller increases in icaA expression contributed significantly to biofilm growth. Interestingly, no biological differences were observed between clinical and commensal strains.

CONCLUSION: These results reinforce the concept that S. epidermidis is an 'accidental pathogen,' and that the ica operon is the main mechanism of biofilm formation in clinical and commensal isolates.}, } @article {pmid29468490, year = {2018}, author = {Guoqi, W and Zhirui, L and Song, W and Tongtong, L and Lihai, Z and Licheng, Z and Peifu, T}, title = {Negative pressure wound therapy reduces the motility of Pseudomonas aeruginosa and enhances wound healing in a rabbit ear biofilm infection model.}, journal = {Antonie van Leeuwenhoek}, volume = {111}, number = {9}, pages = {1557-1570}, pmid = {29468490}, issn = {1572-9699}, support = {81472112//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Bacterial Load ; Bacterial Translocation ; Biofilms/*growth & development ; DNA, Bacterial/analysis ; *Disease Models, Animal ; Ear, External/injuries ; *Negative-Pressure Wound Therapy ; Pseudomonas Infections/microbiology/*therapy ; Pseudomonas aeruginosa/growth & development/*physiology ; Rabbits ; Virulence Factors/analysis ; *Wound Healing ; Wound Infection/microbiology/*therapy ; }, abstract = {Pseudomonas aeruginosa motility, virulence factors and biofilms are known to be detrimental to wound healing. The efficacy of negative pressure wound therapy (NPWT) against P. aeruginosa has been little studied, either in vitro or in vivo. The present study evaluated the effect of negative pressure (NP) on P. aeruginosa motility in vitro, and the effect of NPWT on virulence factors and biofilms in vivo. P. aeruginosa motility was quantified under different levels of NP (atmospheric pressure, - 75, - 125, - 200 mmHg) using an in vitro model. Swimming, swarming and twitching motility were significantly inhibited by NP (- 125 and - 200 mmHg) compared with atmospheric pressure (p = 0.05). Virulence factors and biofilm components were quantified in NPWT and gauze treated groups using a rabbit ear biofilm model. Biofilm structure was studied with fluorescence microscopy and scanning electron microscopy. Additionally, viable bacterial counts and histological wound healing parameters were measured. Compared with the control, NPWT treatment resulted in a significant reduction in expression of all virulence factors assayed including exotoxin A, rhamnolipid and elastase (p = 0.01). A significant reduction of biofilm components (eDNA) (p = 0.01) was also observed in the NPWT group. The reduction of biofilm matrix was verified by fluorescence- and scanning electron-microscopy. NPWT lead to better histologic parameters (p = 0.01) and decreased bacterial counts (p = 0.05) compared with the control. NPWT treatment was demonstrated to be an effective strategy to reduce virulence factors and biofilm components, which may explain the increased wound healing observed.}, } @article {pmid29467723, year = {2018}, author = {Escribano-Viana, R and López-Alfaro, I and López, R and Santamaría, P and Gutiérrez, AR and González-Arenzana, L}, title = {Impact of Chemical and Biological Fungicides Applied to Grapevine on Grape Biofilm, Must, and Wine Microbial Diversity.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {59}, pmid = {29467723}, issn = {1664-302X}, abstract = {This study was aimed to measure the impact of the application of a bio-fungicide against Botrytis cinerea on the microbiota involved in the alcoholic fermentation (AF) of Tempranillo Rioja wines. For this purpose, a bio-fungicide composed of the biological control bacterium Bacillus subtilis QST713 was applied to the vineyard. The microbial diversity was analyzed from grape biofilm to wine. Impact on microbial diversity was measured employing indexes assessed with the software PAST 3.10 P.D. Results were compared to non-treated samples and to samples treated with a chemical fungicide mainly composed by fenhexamid. Overall, the impact of the biological-fungicide (bio-fungicide) on the microbial diversity assessed for grape biofilm and for musts was not remarkable. Neither of the tested fungicides enhanced the growth of any species or acted against the development of any microbial groups. The bio-fungicide had no significant impact on the wine microbiota whereas the chemical fungicide caused a reduction of microbial community richness and diversity. Although environmental threats might generate a detriment of the microbial species richness, in this study the tested bio-fungicide did not modify the structure of the microbial community. Indeed, some of the Bacillus applied at the grape surface, were detected at the end of the AF showing its resilience to the harsh environment of the winemaking; in contrast, its impact on wine quality during aging is yet unknown.}, } @article {pmid29466318, year = {2018}, author = {Díaz, M and Castro, M and Copaja, S and Guiliani, N}, title = {Biofilm Formation by the Acidophile Bacterium Acidithiobacillus thiooxidans Involves c-di-GMP Pathway and Pel exopolysaccharide.}, journal = {Genes}, volume = {9}, number = {2}, pages = {}, pmid = {29466318}, issn = {2073-4425}, abstract = {Acidophile bacteria belonging to the Acidithiobacillus genus are pivotal players for the bioleaching of metallic values such as copper. Cell adherence to ores and biofilm formation, mediated by the production of extracellular polymeric substances, strongly favors bioleaching activity. In recent years, the second messenger cyclic diguanylate (c-di-GMP) has emerged as a central regulator for biofilm formation in bacteria. C-di-GMP pathways have been reported in different Acidithiobacillus species; however, c-di-GMP effectors and signal transduction networks are still largely uncharacterized in these extremophile species. Here we investigated Pel exopolysaccharide and its role in biofilm formation by sulfur-oxidizing species Acidithiobacillusthiooxidans. We identified 39 open reading frames (ORFs) encoding proteins involved in c-di-GMP metabolism and signal transduction, including the c-di-GMP effector protein PelD, a structural component of the biosynthesis apparatus for Pel exopolysaccharide production. We found that intracellular c-di-GMP concentrations and transcription levels of pel genes were higher in At. thiooxidans biofilm cells compared to planktonic ones. By developing an At. thiooxidans ΔpelD null-mutant strain we revealed that Pel exopolysaccharide is involved in biofilm structure and development. Further studies are still necessary to understand how Pel biosynthesis is regulated in Acidithiobacillus species, nevertheless these results represent the first characterization of a c-di-GMP effector protein involved in biofilm formation by acidophile species.}, } @article {pmid29463601, year = {2018}, author = {Tischler, AH and Lie, L and Thompson, CM and Visick, KL}, title = {Discovery of Calcium as a Biofilm-Promoting Signal for Vibrio fischeri Reveals New Phenotypes and Underlying Regulatory Complexity.}, journal = {Journal of bacteriology}, volume = {200}, number = {15}, pages = {}, pmid = {29463601}, issn = {1098-5530}, support = {R01 GM114288/GM/NIGMS NIH HHS/United States ; }, mesh = {Aliivibrio fischeri/drug effects/*physiology ; Bacterial Proteins/genetics/*metabolism ; Bacteriological Techniques ; Biofilms/*growth & development ; Calcium/*pharmacology ; Gene Expression Regulation, Bacterial/*physiology ; }, abstract = {Vibrio fischeri uses biofilm formation to promote symbiotic colonization of its squid host, Euprymna scolopes Control over biofilm formation is exerted at the level of transcription of the symbiosis polysaccharide (syp) locus by a complex set of two-component regulators. Biofilm formation can be induced by overproduction of the sensor kinase RscS, which requires the activities of the hybrid sensor kinase SypF and the response regulator SypG and is negatively regulated by the sensor kinase BinK. Here, we identify calcium as a signal that promotes biofilm formation by biofilm-competent strains under conditions in which biofilms are not typically observed (growth with shaking). This was true for RscS-overproducing cells as well as for strains in which only the negative regulator binK was deleted. The latter results provided, for the first time, an opportunity to induce and evaluate biofilm formation without regulator overexpression. Using these conditions, we determined that calcium induces both syp-dependent and bacterial cellulose synthesis (bcs)-dependent biofilms at the level of transcription of these loci. The calcium-induced biofilms were dependent on SypF, but SypF's Hpt domain was sufficient for biofilm formation. These data suggested the involvement of another sensor kinase(s) and led to the discovery that both RscS and a previously uncharacterized sensor kinase, HahK, functioned in this pathway. Together, the data presented here reveal both a new signal and biofilm phenotype produced by V. fischeri cells, the coordinate production of two polysaccharides involved in distinct biofilm behaviors, and a new regulator that contributes to control over these processes.IMPORTANCE Biofilms, or communities of surface-attached microorganisms adherent via a matrix that typically includes polysaccharides, are highly resistant to environmental stresses and are thus problematic in the clinic and important to study. Vibrio fischeri forms biofilms to colonize its symbiotic host, making this organism useful for studying biofilms. Biofilm formation depends on the syp polysaccharide locus and its regulators. Here, we identify a signal, calcium, that induces both SYP-PS and cellulose-dependent biofilms. We also identify a new syp regulator, the sensor kinase HahK, and discover a mutant phenotype for the sensor kinase RscS. This work thus reveals a specific biofilm-inducing signal that coordinately controls two polysaccharides, identifies a new regulator, and clarifies the regulatory control over biofilm formation by V. fischeri.}, } @article {pmid29463543, year = {2018}, author = {Sheraton, MV and Yam, JKH and Tan, CH and Oh, HS and Mancini, E and Yang, L and Rice, SA and Sloot, PMA}, title = {Mesoscopic Energy Minimization Drives Pseudomonas aeruginosa Biofilm Morphologies and Consequent Stratification of Antibiotic Activity Based on Cell Metabolism.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {5}, pages = {}, pmid = {29463543}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Pseudomonas aeruginosa/cytology/*drug effects/*metabolism ; }, abstract = {Segregation of bacteria based on their metabolic activities in biofilms plays an important role in the development of antibiotic resistance. Mushroom-shaped biofilm structures, which are reported for many bacteria, exhibit topographically varying levels of multiple drug resistance from the cap of the mushroom to its stalk. Understanding the dynamics behind the formation of such structures can aid in design of drug delivery systems, antibiotics, or physical systems for removal of biofilms. We explored the development of metabolically heterogeneous Pseudomonas aeruginosa biofilms using numerical models and laboratory knockout experiments on wild-type and chemotaxis-deficient mutants. We show that chemotactic processes dominate the transformation of slender and hemispherical structures into mushroom structures with a signature cap. Cellular Potts model simulation and experimental data provide evidence that accelerated movement of bacteria along the periphery of the biofilm, due to nutrient cues, results in the formation of mushroom structures and bacterial segregation. Multidrug resistance of bacteria is one of the most threatening dangers to public health. Understanding the mechanisms of the development of mushroom-shaped biofilms helps to identify the multidrug-resistant regions. We decoded the dynamics of the structural evolution of bacterial biofilms and the physics behind the formation of biofilm structures as well as the biological triggers that produce them. Combining in vitro gene knockout experiments with in silico models showed that chemotactic motility is one of the main driving forces for the formation of stalks and caps. Our results provide physicists and biologists with a new perspective on biofilm removal and eradication strategies.}, } @article {pmid29462817, year = {2018}, author = {Yin, S and Jiang, B and Huang, G and Zhang, Y and You, B and Chen, Y and Gong, Y and Chen, J and Yuan, Z and Zhao, Y and Li, M and Hu, F and Yang, Z and Peng, Y}, title = {The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation.}, journal = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology}, volume = {45}, number = {4}, pages = {1399-1409}, doi = {10.1159/000487566}, pmid = {29462817}, issn = {1421-9778}, mesh = {Acetylcysteine/*pharmacology/therapeutic use ; Animals ; Bacterial Infections/drug therapy/pathology/veterinary ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Disease Models, Animal ; Extracellular Matrix/metabolism ; Humans ; Male ; Microscopy, Confocal ; Pseudomonas aeruginosa/metabolism ; Rats ; Rats, Sprague-Dawley ; Staphylococcus aureus/*physiology ; Transcription Factors/genetics/metabolism ; Transferrins/*pharmacology ; }, abstract = {BACKGROUND/AIMS: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone.

METHODS: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo.

RESULTS: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters.

CONCLUSIONS: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.}, } @article {pmid29462616, year = {2018}, author = {Yang, WS and Hong, Y and Zhang, Y and Wang, DC and Li, DF and Hou, YJ}, title = {A potential substrate binding pocket of BdcA plays a critical role in NADPH recognition and biofilm dispersal.}, journal = {Biochemical and biophysical research communications}, volume = {497}, number = {3}, pages = {863-868}, doi = {10.1016/j.bbrc.2018.02.143}, pmid = {29462616}, issn = {1090-2104}, mesh = {Binding Sites ; *Biofilms ; Crystallography, X-Ray ; Escherichia coli/chemistry/cytology/*physiology ; Escherichia coli Proteins/chemistry/*metabolism ; Molecular Docking Simulation ; NADP/chemistry/*metabolism ; Protein Conformation ; Substrate Specificity ; }, abstract = {Biofilm dispersal is characterized by the cell detachment from biofilms and expected to provide novel "anti-biofilm" approaches of prevention and treatment of biofilms in clinical and industrial settings. The E.coli protein BdcA has been identified as a biofilm dispersal factor and designed to be an important component in engineered applications to control biofilm formation. It belongs to short-chain dehydrogenase/reductase (SDR) family with the specific affinity to NADPH. Here, we show the structure of BdcA in complex with NADPH and confirm that NADPH binding is requisite for BdcA facilitating cell motility and increasing biofilm dispersal. Especially, we observe a potential substrate binding pocket surrounded by hydrophobic residues upon NADPH binding and present evidences that this pocket is essential for BdcA binding NADPH and exerting its biological functions. Our study provides the clues for illuminating the molecular mechanism of BdcA regulating biofilm dispersal and better utilizing BdcA to eliminate the biofilms.}, } @article {pmid29462463, year = {2018}, author = {Khattak, F and Paschalis, V and Green, M and Houdijk, JGM and Soultanas, P and Mahdavi, J}, title = {TYPLEX® Chelate, a novel feed additive, inhibits Campylobacter jejuni biofilm formation and cecal colonization in broiler chickens.}, journal = {Poultry science}, volume = {97}, number = {4}, pages = {1391-1399}, pmid = {29462463}, issn = {1525-3171}, mesh = {Animal Feed/analysis ; Animals ; Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Campylobacter Infections/drug therapy/microbiology/*veterinary ; Campylobacter jejuni/drug effects/*physiology ; Cecum/microbiology ; *Chickens ; Diet/veterinary ; Dietary Supplements/analysis ; Escherichia coli/drug effects ; Escherichia coli Infections/drug therapy/microbiology/*veterinary ; Male ; Poultry Diseases/*drug therapy/microbiology ; Random Allocation ; }, abstract = {Reducing Campylobacter spp. carriage in poultry is challenging, but essential to control this major cause of human bacterial gastroenteritis worldwide. Although much is known about the mechanisms and route of Campylobacter spp. colonization in poultry, the literature is scarce on antibiotic-free solutions to combat Campylobacter spp. colonization in poultry. In vitro and in vivo studies were conducted to investigate the role of TYPLEX® Chelate (ferric tyrosine), a novel feed additive, in inhibiting Campylobacter jejuni (C. jejuni) biofilm formation and reducing C. jejuni and Escherichia coli (E. coli) colonization in broiler chickens at market age. In an in vitro study, the inhibitory effect on C. jejuni biofilm formation using a plastic bead assay was investigated. The results demonstrated that TYPLEX® Chelate significantly reduces biofilm formation. In an in vivo study, 800 broilers (one d old) were randomly allocated to 4 dietary treatments in a randomized block design, each having 10 replicate pens with 20 birds per pen. At d 21, all birds were challenged with C. jejuni via seeded litter. At d 42, cecal samples were collected and tested for volatile fatty acid (VFA) concentrations and C. jejuni and E. coli counts. The results showed that TYPLEX® Chelate reduced the carriage of C. jejuni and E. coli in poultry by 2 and 1 log10 per gram cecal sample, respectively, and increased cecal VFA concentrations. These findings support TYPLEX® Chelate as a novel non-antibiotic feed additive that may help produce poultry with a lower public health risk of Campylobacteriosis.}, } @article {pmid29459912, year = {2018}, author = {Farid, MU and Jeong, S and Seo, DH and Ahmed, R and Lau, C and Gali, NK and Ning, Z and An, AK}, title = {Mechanistic insight into the in vitro toxicity of graphene oxide against biofilm forming bacteria using laser-induced breakdown spectroscopy.}, journal = {Nanoscale}, volume = {10}, number = {9}, pages = {4475-4487}, doi = {10.1039/c8nr00189h}, pmid = {29459912}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Escherichia coli/*drug effects ; Graphite/*pharmacology ; Lasers ; Oxidative Stress ; Oxides ; Reactive Oxygen Species/metabolism ; Spectrum Analysis ; Staphylococcus aureus/*drug effects ; }, abstract = {While the cytotoxicity of graphene oxide (GO) has been well established, its bactericidal mechanism, however, has yet to be elucidated to advance GO-based biomedical and environmental applications. In an attempt to better understand the bactericidal action of GO, herein we studied the interactions of GO with Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus cells using physical techniques and chemical probes, respectively. In particular, a novel laser-induced breakdown spectroscopy (LIBS) based elemental fingerprint analysis revealed notable differences between viable and non-viable cells based on the difference in the concentration of trace inorganic elements in complex bacterial systems, which reflect cellular membrane integrity. Lower emission intensities from essential inorganic ions in the GO-treated cells offered explicit evidence on the efflux of intracellular molecules from the bacteria through damaged cell membranes. Furthermore, a detailed structural and morphological investigation of bacterial membrane integrity confirmed GO-induced membrane stress upon direct contact interactions with bacterial cells, resulting in the disruption of cellular membranes. Moreover, the generation of intracellular reactive oxygen species (ROS) in the presence of an added antioxidant underlined the role of GO-mediated oxidative stress in bacterial cell inactivation. Thus, by correlating the changes in the bacterial elemental compositions with the severe morphological alterations and the high ROS production witnessed herein, we propose that the bactericidal mechanism of GO is likely to be the synergy between membrane and oxidative stress towards both tested species. Our findings offer useful guidelines for the future development of GO-based antibacterial surfaces and coatings.}, } @article {pmid29459854, year = {2018}, author = {Ling, N and Zhang, J and Li, C and Zeng, H and He, W and Ye, Y and Wu, Q}, title = {The Glutaredoxin Gene, grxB, Affects Acid Tolerance, Surface Hydrophobicity, Auto-Aggregation, and Biofilm Formation in Cronobacter sakazakii.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {133}, pmid = {29459854}, issn = {1664-302X}, abstract = {Cronobacter species are foodborne pathogens that can cause neonatal meningitis, necrotizing enterocolitis, and sepsis; they have unusual abilities to survive in environmental stresses such as acid stress. However, the factors involved in acid stress responses and biofilm formation in Cronobacter species are poorly understood. In this study, we investigated the role of grxB on cellular morphology, acid tolerance, surface hydrophobicity, auto-aggregation (AAg), motility, and biofilm formation in Cronobacter sakazakii. The deletion of grxB decreased resistance to acid stresses, and notably led to weaker surface hydrophobicity, AAg, and biofilm formation under normal and acid stress conditions, compared with those of the wild type strain; however, motility was unaffected. Therefore, grxB appears to contribute to the survival of C. sakazakii in acid stresses and biofilm formation. This is the first report to provide valuable evidence for the role of grxB in acid stress responses and biofilm formation in C. sakazakii.}, } @article {pmid29459646, year = {2018}, author = {Liu, D and Li, J and Li, C and Deng, Y and Zhang, Z and Ye, Z and Zhu, S}, title = {Poly(butylene succinate)/bamboo powder blends as solid-phase carbon source and biofilm carrier for denitrifying biofilters treating wastewater from recirculating aquaculture system.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {3289}, pmid = {29459646}, issn = {2045-2322}, abstract = {In this study, Poly(butylene succinate)/bamboo powder (PBS/BP) was newly applied and tested for 8 months as the carbon source in two moving bed reactors for nitrate removal in real RAS wastewater (fresh/sea water), with the purposes of simultaneous reducing the cost of PBS packing and effluent DOC. Fast start-ups were obtained in both reactors, in which high denitrification rates were observed (0.68 ± 0.03 and 0.83 ± 0.11 kg [Formula: see text]-N m[-3] d[-1] for fresh and sea water, respectively) with no nitrite and low ammonia accumulation. Reduced DOC concentrations in the effluents were also observed compared to pure PBS. The freezing of PBS/BP showed a further slower release of DOC, which might be beneficial to the life of the PBS/BP for the denitrification process, however, microbial activity, especially in high salinity wastewater, was observed to have declined. Illumina sequencing revealed that the autotrophic genus arcobacter was discovered first time in solid-phase denitrification system with salinity. Redundancy analysis (RDA) was used to reveal the relationships between environmental factors and the microbial community. In overall, PBS/BP blends were proven to be an economically attractive carbon source for nitrate removal in RAS.}, } @article {pmid29458854, year = {2018}, author = {Subramenium, GA and Swetha, TK and Iyer, PM and Balamurugan, K and Pandian, SK}, title = {5-hydroxymethyl-2-furaldehyde from marine bacterium Bacillus subtilis inhibits biofilm and virulence of Candida albicans.}, journal = {Microbiological research}, volume = {207}, number = {}, pages = {19-32}, doi = {10.1016/j.micres.2017.11.002}, pmid = {29458854}, issn = {1618-0623}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Bacillus subtilis/*metabolism ; Biofilms/*drug effects ; Caenorhabditis elegans/drug effects/pathogenicity ; Candida albicans/*drug effects/*pathogenicity ; Clotrimazole/pharmacology ; Drug Synergism ; Ergosterol/metabolism ; Furaldehyde/*analogs & derivatives/pharmacology ; Hyphae/growth & development ; Ketoconazole/pharmacology ; Miconazole/pharmacology ; Virulence/drug effects ; }, abstract = {Candida albicans is considered as the primary etiologic agent of candidiasis, a very common fungal infection in human. The yeast to hyphal transition and ability to form hypoxic biofilm on medical devices is well allied with virulence and antifungal resistance of C. albicans. Antagonistic agents that inhibit biofilm formation and alter susceptibility of C. albicans to conventional antifungals is of profound need. The present study explores the antibiofilm efficacy of Bacillus subtilis, a marine bacterial isolate from Palk Bay against C. albicans. Mass spectrometric analysis of ethyl acetate extract of B. subtilis unveiled 5-hydroxymethyl-2-furaldehyde (5HM2F) as one of its major components. 5HM2F demonstrated concentration dependent biofilm inhibition, which was also corroborated through microscopic analysis. Furthermore, 5HM2F was effective in inhibiting other virulence factors of C. albicans such as morphological transition and secreted hydrolases production. Fourier transform infrared spectroscopic analysis showed alteration in amide bond region. The reduction in ergosterol content and increased antifungal susceptibility was well allied with real time PCR result, which showed down regulation of genes involved in drug resistance mechanisms. In vivo study using Caenorhabditis elegans also substantiated the antivirulence efficacy of 5HM2F at in vivo condition. Thus, the present study reports the therapeutic potential of 5HM2F against C. albicans infections.}, } @article {pmid29458673, year = {2018}, author = {Morse, DJ and Wilson, MJ and Wei, X and Lewis, MAO and Bradshaw, DJ and Murdoch, C and Williams, DW}, title = {Denture-associated biofilm infection in three-dimensional oral mucosal tissue models.}, journal = {Journal of medical microbiology}, volume = {67}, number = {3}, pages = {364-375}, pmid = {29458673}, issn = {1473-5644}, mesh = {Biofilms/*growth & development ; Candida albicans/genetics/pathogenicity/physiology ; Candidiasis, Oral/*microbiology ; Cell Line ; Coinfection/microbiology ; Dentures/*microbiology ; Fibroblasts/microbiology ; *Host-Pathogen Interactions ; Humans ; Keratinocytes/microbiology ; Mouth Mucosa/*microbiology ; Polymethyl Methacrylate ; Stomatitis, Denture ; Virulence ; }, abstract = {PURPOSE: In vitro analyses of virulence, pathogenicity and associated host cell responses are important components in the study of biofilm infections. The Candida-related infection, denture-associated oral candidosis, affects up to 60 % of denture wearers and manifests as inflammation of palatal tissues contacting the denture-fitting surface. Commercially available three-dimensional tissue models can be used to study infection, but their use is limited for many academic research institutions, primarily because of the substantial purchase costs. The aim of this study was to develop and evaluate the use of in vitro tissue models to assess infections by biofilms on acrylic surfaces through tissue damage and Candida albicans virulence gene expression.

METHODOLOGY: In vitro models were compared against commercially available tissue equivalents (keratinocyte-only, SkinEthic; full-thickness, MatTek Corporation). An in vitro keratinocyte-only tissue was produced using a cancer-derived cell line, TR146, and a full-thickness model incorporating primary fibroblasts and immortalised normal oral keratinocytes was also generated. The in vitro full-thickness tissues incorporated keratinocytes and fibroblasts, and have potential for future further development and analysis.

RESULTS: Following polymicrobial infection with biofilms on acrylic surfaces, both in-house developed models were shown to provide equivalent results to the SkinEthic and MatTek models in terms of tissue damage: a significant (P<0.05) increase in LDH activity for mixed species biofilms compared to uninfected control, and no significant difference (P>0.05) in the expression of most C. albicans virulence genes when comparing tissue models of the same type.

CONCLUSION: Our results confirm the feasibility and suitability of using these alternative in vitro tissue models for such analyses.}, } @article {pmid29458668, year = {2018}, author = {Al-Ahmad, A and Muzafferiy, F and Anderson, AC and Wölber, JP and Ratka-Krüger, P and Fretwurst, T and Nelson, K and Vach, K and Hellwig, E}, title = {Shift of microbial composition of peri-implantitis-associated oral biofilm as revealed by 16S rRNA gene cloning.}, journal = {Journal of medical microbiology}, volume = {67}, number = {3}, pages = {332-340}, doi = {10.1099/jmm.0.000682}, pmid = {29458668}, issn = {1473-5644}, mesh = {Aged ; Aged, 80 and over ; Bacteria/classification/genetics/*isolation & purification ; Bacterial Load ; Bacterial Physiological Phenomena ; Bacteroides/genetics/isolation & purification ; *Biofilms ; Female ; Fusobacterium nucleatum/genetics/isolation & purification ; Genes, rRNA ; Gingiva/microbiology ; Humans ; Male ; Microbiota/*genetics ; Middle Aged ; Peri-Implantitis/*microbiology ; Porphyromonas gingivalis/genetics/isolation & purification ; Prevotella intermedia/genetics/isolation & purification ; RNA, Ribosomal, 16S/*genetics ; Sequence Analysis, DNA ; }, abstract = {PURPOSE: Micro-organisms are important triggers of peri-implant inflammation and analysing their diversity is necessary for peri-implantitis treatment. This study aimed to analyse and compare the microbiota associated with individuals with peri-implantitis, as well as clinically healthy implant sites.

METHODOLOGY: Subgingival biofilm samples were taken from 10 individuals with peri-implantitis and from at least 1 clinically healthy implant. DNA was extracted and bacterial 16S rRNA genes were amplified using universal primers. After cloning the PCR-products, amplified inserts of positive clones were digested using restriction endonucleases, and the chosen clones were sequenced. The 16S rDNA-sequences were compared to those from the public sequence databases GenBank, EMBL and DDBJ to determine the corresponding taxa.

RESULTS: Differing distributions of taxa belonging to the phyla Firmicutes, Bacteroidetes, Fusobacteria, Actinobacteria, Proteobacteria, Synergistetes, Spirochaetae and TM 7 were detected in both the healthy implant (HI) and the peri-implantitis (PI) groups. A significantly higher relative abundance of phylum Bacteroidetes, as well as of the species Fusobacterium nucleatum, were found in the PI group (P<0.05). The putative periodontal red complex (Porphyromonas gingivalis, Tannerella forsythia) was also detected at significantly higher levels in the PI group (P<0.05), whereas the yellow group, as well as the species Veillonella dispar, tended to be associated with the HI group.

CONCLUSION: A shift in the healthy subgingival microbiota was shown in peri-implantitis-associated biofilm. Anaerobic Gram-negative periopathogens, including P. gingivalis and T. forsythia, seem to play an important role in peri-implantitis development and should be considered in treatment and prevention strategies.}, } @article {pmid29458564, year = {2018}, author = {Mashima, I and Liao, YC and Miyakawa, H and Theodorea, CF and Thawboon, B and Thaweboon, S and Scannapieco, FA and Nakazawa, F}, title = {Veillonella infantium sp. nov., an anaerobic, Gram-stain-negative coccus isolated from tongue biofilm of a Thai child.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {68}, number = {4}, pages = {1101-1106}, doi = {10.1099/ijsem.0.002632}, pmid = {29458564}, issn = {1466-5034}, mesh = {Bacterial Typing Techniques ; *Biofilms ; Child ; DNA, Bacterial/genetics ; Genes, Bacterial ; Humans ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Thailand ; Tongue/*microbiology ; Veillonella/*classification/genetics/isolation & purification ; }, abstract = {A strain of a novel anaerobic, Gram-stain-negative coccus was isolated from the tongue biofilm of a Thai child. This strain was shown, at the phenotypic level and based on 16S rRNA gene sequencing, to be a member of the genus Veillonella. Comparative analysis of the 16S rRNA, dnaK and rpoB gene sequences indicated that phylogenetically the strain comprised a distinct novel branch within the genus Veillonella. The novel strain showed 99.8, 95.1 and 95.9 % similarity to partial 16S rRNA, dnaK and rpoB gene sequences, respectively, to the type strains of the two most closely related species, Veillonelladispar ATCC 17748[T] and Veillonellatobetsuensis ATCC BAA-2400[T]. The novel strain could be discriminated from previously reported species of the genus Veillonella based on partial dnaK and rpoB gene sequencing and average nucleotide identity values. The major acid end-product produced by this strain was acetic acid under anaerobic conditions in trypticase-yeast extract-haemin with 1 % (w/v) glucose or fructose medium. Lactate was fermented to acetic acid and propionic acid. Based on these observations, this strain represents a novel species, for which the name Veillonella infantium sp. nov. is proposed. The type strain is T11011-4[T] (=JCM 31738[T]=TSD-88[T]).}, } @article {pmid29456814, year = {2018}, author = {Ali Mirani, Z and Khan, MN and Siddiqui, A and Khan, F and Aziz, M and Naz, S and Ahmed, A and Khan, SI}, title = {Ascorbic acid augments colony spreading by reducing biofilm formation of methicillin-resistant Staphylococcus aureus.}, journal = {Iranian journal of basic medical sciences}, volume = {21}, number = {2}, pages = {175-180}, pmid = {29456814}, issn = {2008-3866}, abstract = {OBJECTIVES: Staphylococcus aureus is a Gram-positive pathogen, well known for its resistance and versatile lifestyle. Under unfavourable conditions, it adapts biofilm mode of growth. For staphylococcal biofilm formation, production of extracellular polymeric substances (EPS) is a pre-requisite, which is regulated by ica operon-encoded enzymes. This study was designed to know the impact of ascorbic acid on biofilm formation and colony spreading processes of S. aureus and MRSA.

MATERIALS AND METHODS: The isolates of methicillin-resistant S. aureus (MRSA) used in present study, were recovered from different food samples. Various selective and differential media were used for identification and confirmation of S. aureus. Agar dilution method was used for determination of oxacillin and ascorbic acid resistance level. MRSA isolates were re-confirmed by E-test and by amplification of mecA gene. Tube methods and Congo-Red agar were used to study biofilm formation processes. Gene expression studies were carried on real-time reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS: The results revealed the presence of mecA gene belonging to SCCmecA type IV along with agr type II in the isolates. In vitro studies showed the sub-inhibitory concentration of oxacillin induced biofilm production. However, addition of sub-inhibitory dose of ascorbic acid was found to inhibit EPS production, biofilm formation and augment colony spreading on soft agar plates. The inhibition of biofilm formation and augmentation of colony spreading observed with ascorbic acid alone or in combination with oxacillin. Moreover, gene expression studies showed that ascorbic acid increases agr expression and decreases icaA gene expression.

CONCLUSION: The present study concluded that ascorbic acid inhibits biofilm formation, promotes colony spreading and increases agr gene expression in MRSA.}, } @article {pmid29453048, year = {2018}, author = {Zhang, S and Song, HL and Yang, XL and Li, H and Wang, YW}, title = {A system composed of a biofilm electrode reactor and a microbial fuel cell-constructed wetland exhibited efficient sulfamethoxazole removal but induced sul genes.}, journal = {Bioresource technology}, volume = {256}, number = {}, pages = {224-231}, doi = {10.1016/j.biortech.2018.02.023}, pmid = {29453048}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Sulfamethoxazole ; Wastewater ; Wetlands ; }, abstract = {The aim of this work was to study sulfamethoxazole (SMX) removal efficiency and fate of corresponding sul genes in a stacked microbial fuel cell-constructed wetland coupled biofilm electrode reactor system (MFC-CW-BER). Findings showed that two stacked MFC-CWs could provide a relatively stable electricity supply to support the biofilm for SMX removal. Excellent SMX removal (>99.29%) was obtained in the BER-MFC-CW. Compared with the 2000 µg L[-1] SMX influent, the relative abundance of the sul genes in biofilm media and effluent was enhanced with continuously high concentrations of SMX (4000 μg L[-1]). The relative abundances of sul genes in biofilm media and effluent increased as the hydraulic retention time decreased. However, there was no obvious variation in the relative abundance of sul genes in the effluent from MFC-CWs. No effect could be observe of the direct voltage and bioelectricity on the relative abundance of the sul genes in the BER.}, } @article {pmid29452851, year = {2018}, author = {Brandão, ISL and Oliveira-Moraes, HMDS and Souza Motta, CM and Oliveira, NT and Magalhães, OMC}, title = {Elastin increases biofilm and extracellular matrix production of Aspergillus fumigatus.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {49}, number = {3}, pages = {675-682}, pmid = {29452851}, issn = {1678-4405}, mesh = {Aspergillosis/*metabolism/*microbiology ; Aspergillus fumigatus/genetics/*physiology ; *Biofilms ; Elastin/*metabolism ; Extracellular Matrix/*metabolism ; Host-Pathogen Interactions ; Humans ; }, abstract = {Aspergillus fumigatus is an opportunistic saprobe fungus that accounts for 90% of cases of pulmonary aspergillosis in immunosuppressed patients and is known for its angiotropism. When it reaches the respiratory tract, A. fumigatus interacts with structural components and blood vessels of the lungs, such as elastin. To understand the effect of this structural component, we examined the effect of elastin on the production and development of the biofilm of A. fumigatus. In RPMI containing 10mg/mL of elastin, a significant increase (absorbance p<0.0001; dry weight p<0.0001) in the production of biofilm was observed in comparison to when RPMI was used alone, reaching a maximum growth of 18.8mg (dry weight) of biofilm in 72h. In addition, elastin stimulates the production (p=0.0042) of extracellular matrix (ECM) and decreases (p=0.005) the hydrophobicity during the development of the biofilm. These results suggest that elastin plays an important role in the growth of A. fumigatus and that it participates in the formation of thick biofilm.}, } @article {pmid29452197, year = {2018}, author = {Wijesundara, NM and Rupasinghe, HPV}, title = {Essential oils from Origanum vulgare and Salvia officinalis exhibit antibacterial and anti-biofilm activities against Streptococcus pyogenes.}, journal = {Microbial pathogenesis}, volume = {117}, number = {}, pages = {118-127}, doi = {10.1016/j.micpath.2018.02.026}, pmid = {29452197}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bicyclic Monoterpenes ; Biofilms/*drug effects ; Camphor ; Cymenes ; Microbial Sensitivity Tests ; Monoterpenes ; Oils, Volatile/chemistry/*pharmacology ; Origanum/*chemistry ; Phytochemicals/pharmacology ; Plant Extracts/chemistry/*pharmacology ; Salvia officinalis/*chemistry ; Streptococcus pyogenes/*drug effects/growth & development ; }, abstract = {In the present study, essential oils (EOs) extracted from oregano, sage, cloves, and ginger were evaluated for the phytochemical profile, antibacterial, and anti-biofilm activities against Streptococcus pyogenes. The broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of EOs. The minimum biofilm inhibitory concentrations (MBICs) were determined using MTT assay and fixed biofilms were observed through scan electron microscopy. The oregano and sage EOs showed the lowest MIC as well as MBC of 0.25-0.5 mg/mL. Time kill assay results showed that oregano and sage EOs exhibited bactericidal effects within 5 min and 4 h, respectively. Both oregano and sage extracts acts as a potent anti-biofilm agent with dual actions, preventing and eradicating the biofilm. The microscopic visualization of biofilms treated with EOs have shown morphological and density changes compared to the untreated control. Oregano EO was constituted predominantly carvacrol (91.6%) and in sage EO, higher levels of α-thujone (28.5%) and camphor (16.6%) were revealed. EOs of oregano and sage inhibit the growth and biofilm formation of S. pyogenes. Effective concentrations of oregano and sage EOs and their phytochemicals can be used in developing potential plant-derived antimicrobial agents in the management of streptococcal pharyngitis.}, } @article {pmid29451651, year = {2018}, author = {Estrela, C and Costa E Silva, R and Urban, RC and Gonçalves, PJ and Silva, JA and Estrela, CRA and Pecora, JD and Peters, OA}, title = {Demetallization of Enterococcus faecalis biofilm: a preliminary study.}, journal = {Journal of applied oral science : revista FOB}, volume = {26}, number = {}, pages = {e20170374}, pmid = {29451651}, issn = {1678-7765}, mesh = {Animals ; Biofilms/*drug effects ; Calcium/analysis ; Cattle ; Chelating Agents/chemistry/*pharmacology ; Dental Pulp Cavity/chemistry/*drug effects/*microbiology ; Edetic Acid/chemistry/pharmacology ; Enterococcus faecalis/chemistry/*drug effects ; Hydrogen-Ion Concentration ; Ions ; Iron/analysis ; Manganese/analysis ; Materials Testing ; Root Canal Irrigants/chemistry/pharmacology ; Sodium Hypochlorite/chemistry/pharmacology ; Spectrophotometry, Atomic ; Water/chemistry ; Zinc/analysis ; }, abstract = {Objectives To determine the concentration of calcium, iron, manganese and zinc ions after the application of chelator to Enterococcus faecalis biofilms. Material and Methods Fifty bovine maxillary central incisors were prepared and inoculated with E. faecalis for 60 days. The following were used as irrigation solutions: 17% EDTA (pH 3, 7 and 10), 2.5% sodium hypochlorite (NaOCl) combined with 17% EDTA (pH 3, 7 and 10), distilled water (pH 3, 7 and 10), and 2.5% NaOCl. Each solution was kept in the root canal for five minutes. Fifteen uncontaminated root canals were irrigated with 17% EDTA (pH 3, 7 and 10). Six teeth were used as bacterial control. The number of calcium, iron, manganese and zinc ions was determined using flame atomic absorption spectrometry. Mean ± standard deviation (SD) values were used for descriptive statistics. Results Calcium chelation using 17% EDTA at pH 7 was higher than at pH 3 and 10, regardless of whether bacterial biofilm was present. The highest concentration of iron occurred at pH 3 in the presence of bacterial biofilm. The highest concentration of manganese found was 2.5% NaOCl and 17% EDTA at pH 7 in the presence of bacterial biofilm. Zinc levels were not detectable. Conclusions The pH of chelating agents affected the removal of calcium, iron, and manganese ions. The concentration of iron ions in root canals with bacterial biofilm was higher after the use of 17% EDTA at pH 3 than after the use of the other solutions at all pH levels.}, } @article {pmid29451388, year = {2018}, author = {Hofbauer, B and Vomacka, J and Stahl, M and Korotkov, VS and Jennings, MC and Wuest, WM and Sieber, SA}, title = {Dual Inhibitor of Staphylococcus aureus Virulence and Biofilm Attenuates Expression of Major Toxins and Adhesins.}, journal = {Biochemistry}, volume = {57}, number = {11}, pages = {1814-1820}, pmid = {29451388}, issn = {1520-4995}, support = {R01 DE025837/DE/NIDCR NIH HHS/United States ; R35 GM119426/GM/NIGMS NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*biosynthesis ; Anti-Bacterial Agents/*pharmacology ; Bacterial Toxins/*biosynthesis ; Biofilms/*drug effects/growth & development ; Gene Expression Regulation, Bacterial/*drug effects ; *Staphylococcus aureus/pathogenicity/physiology ; }, abstract = {Staphylococcus aureus is a major bacterial pathogen that invades and damages host tissue by the expression of devastating toxins. We here performed a phenotypic screen of 35 molecules that were structurally inspired by previous hydroxyamide-based S. aureus virulence inhibitors compiled from commercial sources or designed and synthesized de novo. One of the most potent compounds, AV73, not only reduced hemolytic alpha-hemolysin production in S. aureus but also impeded in vitro biofilm formation. The effect of AV73 on bacterial proteomes and extracellular protein levels was analyzed by quantitative proteomics and revealed a significant down-regulation of major virulence and biofilm promoting proteins. To elucidate the mode of action of AV73, target identification was performed using affinity-based protein profiling (AfBPP), where among others YidC was identified as a target.}, } @article {pmid29450709, year = {2018}, author = {Meyer-Dombard, DR and Casar, CP and Simon, AG and Cardace, D and Schrenk, MO and Arcilla, CA}, title = {Biofilm formation and potential for iron cycling in serpentinization-influenced groundwater of the Zambales and Coast Range ophiolites.}, journal = {Extremophiles : life under extreme conditions}, volume = {22}, number = {3}, pages = {407-431}, pmid = {29450709}, issn = {1433-4909}, support = {1147334//Directorate for Geosciences/ ; }, mesh = {*Biofilms ; Biotransformation ; Geologic Sediments/chemistry/*microbiology ; Groundwater/chemistry/*microbiology ; Iron/*metabolism ; *Microbiota ; Oxidation-Reduction ; }, abstract = {Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential 'principal' microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization.}, } @article {pmid29449129, year = {2018}, author = {Otani, S and Hiramatsu, K and Hashinaga, K and Komiya, K and Umeki, K and Kishi, K and Kadota, JI}, title = {Sub-minimum inhibitory concentrations of ceftazidime inhibit Pseudomonas aeruginosa biofilm formation.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {24}, number = {6}, pages = {428-433}, doi = {10.1016/j.jiac.2018.01.007}, pmid = {29449129}, issn = {1437-7780}, mesh = {Analysis of Variance ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Ceftazidime/*pharmacology ; Cell Adhesion/drug effects ; Cell Movement/drug effects ; Humans ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {Pseudomonas aeruginosa exhibits the biofilm mode of growth and causes chronic as well as acute infections in humans. Several reports have shown that the treatments with sub-minimum inhibitory concentrations (sub-MICs) of antimicrobial agents influence biofilm formation by P. aeruginosa. The antibiotic ceftazidime (CAZ) is used to treat P. aeruginosa infections, but few studies have examined the effects of β-lactams on biofilm formation by P. aeruginosa. In this study, we investigated the role of sub-MICs of CAZ in the formation of P. aeruginosa biofilms. 1/4 × MIC CAZ reduced the biofilm volume of P. aeruginosa PAO1, as quantified by crystal violet staining. The formation of P. aeruginosa PAO1 biofilms treated with 1/4 × MIC CAZ were observed by confocal laser scanning microscopy. They were more heterogeneous than the PAO1 biofilms without CAZ treatment. Furthermore, sub-MICs of CAZ inhibited the twitching motility, which played an important role in mature biofilm formation. 1/4 × MIC CAZ also reduced the gene expressions of lecA, lecB, pel and psl, which mediate the adhesion and polysaccharide matrix synthesis of P. aeruginosa. These effects suggest that sub-MICs of CAZ may affect a number of stages of biofilm formation. Investigating the effects of sub-MIC antibiotics on targeted bacterial biofilm may lead to the development of future antibiotic treatment modalities.}, } @article {pmid29449125, year = {2018}, author = {Trang, TTT and Dieltjens, L and Hooyberghs, G and Waldrant, K and Ermolat'ev, DS and Van der Eycken, EV and Steenackers, HPL}, title = {Enhancing the anti-biofilm activity of 5-aryl-2-aminoimidazoles through nature inspired dimerisation.}, journal = {Bioorganic & medicinal chemistry}, volume = {26}, number = {8}, pages = {1470-1480}, doi = {10.1016/j.bmc.2018.01.005}, pmid = {29449125}, issn = {1464-3391}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Biological Products/chemical synthesis/chemistry/*pharmacology ; Dimerization ; Dose-Response Relationship, Drug ; Escherichia coli/drug effects ; Imidazoles/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Microwaves ; Molecular Structure ; Pseudomonas aeruginosa/drug effects ; Salmonella typhimurium/drug effects ; Staphylococcus aureus/drug effects ; Structure-Activity Relationship ; }, abstract = {The increased tolerance of biofilms against disinfectants and antibiotics has stimulated research into new methods of biofilm prevention and eradication. In our previous work, we have identified the 5-aryl-2-aminoimidazole core as a scaffold that demonstrates preventive activity against biofilm formation of a broad range of bacterial and fungal species. Inspired by the dimeric nature of natural 2-aminoimidazoles of the oroidin family, we investigated the potential of dimers of our decorated 5-aryl-2-aminoimidazoles as biofilm inhibitors. A synthetic approach towards 2-aminoimidazole dimers linked by an alkyl chain was developed and a total of 48 dimers were synthesized. The linkers were introduced at two different positions, the N1-position or the N2-position, and the linker length and the substitution of the 5-phenyl ring (H, F, Cl, Br) were varied. Although, no clear correlation between linker length and biofilm inhibition was observed, a strong increase in anti-biofilm activity for almost all N1,N1'-linked dimers was obtained, compared to the respective monomers against Salmonella Typhimurium, Escherichia coli and Staphylococcus aureus. The N2,N2'-linked dimers, having a H- or F-substitution, were also found to show a strong increase in anti-biofilm activity compared to the respective monomers against these three bacterial species and against Pseudomonas aeruginosa. In addition, the obtained growth measurements suggest a broad concentration range with specific biofilm inhibition and no effect on the planktonic growth against Salmonella Typhimurium and Pseudomonas aeruginosa.}, } @article {pmid29448898, year = {2019}, author = {Camiloti, PR and Valdés, F and Delforno, TP and Bartacek, J and Zaiat, M and Jeison, D}, title = {A membrane aerated biofilm reactor for sulfide control from anaerobically treated wastewater.}, journal = {Environmental technology}, volume = {40}, number = {18}, pages = {2354-2363}, doi = {10.1080/09593330.2018.1441329}, pmid = {29448898}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; *Hydrogen Sulfide ; Sewage ; Sulfides ; *Wastewater ; }, abstract = {A upflow anaerobic sludge blanket reactor was operated combined to a membrane aerated biofilm reactor for sulfate removal and for elemental sulfur reclamation. A commercial silicon tube was used as an oxygen delivery diffuser. The process achieved high rates of sulfide removal from the liquid phase (90%). The hydrogen sulfide removal was influenced by the pH value and at pH value of 7.5, 98% of the H2S was removed. The elemental sulfur was observed inside the membrane, with content in the biomass of 21%. Through the massive sequencing of the samples, the microbial community diversity and the stratification of biomass inside the silicon tube was demonstrated, confirming the presence of sulfide-oxidizing bacteria on the membrane wall. The most important genera found related to the sulfur cycle were Sulfuricurvum, Geovibrio, Flexispira and Sulforospirillum.}, } @article {pmid29446687, year = {2018}, author = {Lee, S and Kim, S and Lee, H and Ha, J and Lee, J and Choi, Y and Oh, H and Yoon, Y and Choi, KH}, title = {icaA Gene of Staphylococcus aureus Responds to NaCl, Leading to Increased Biofilm Formation.}, journal = {Journal of food protection}, volume = {81}, number = {3}, pages = {412-416}, doi = {10.4315/0362-028X.JFP-17-238}, pmid = {29446687}, issn = {1944-9097}, mesh = {*Biofilms ; Genes, Bacterial ; Sodium Chloride/*pharmacology ; Staphylococcus aureus/*drug effects/genetics/physiology ; }, abstract = {The objective of this study was to elucidate the role of the icaA gene in biofilm formation of Staphylococcus aureus exposed to NaCl. The icaA-deletion mutant of S. aureus ATCC 13565 was constructed with the temperature-sensitive plasmid pIMAY. Microtiter plate assays were performed to confirm biofilm formation for both the wild type and the mutant at 0% (control), 2, 4, and 6% NaCl. The microtiter plate assay revealed that biofilm formation by the wild type increased (P < 0.05) as NaCl concentration increased, but biofilm formation of the mutant was not affected by NaCl concentration. Biofilm formation by the mutant was lower (P < 0.05) than that by the wild type. These results indicate that icaA plays an important role in biofilm formation by S. aureus when the pathogen is exposed to NaCl.}, } @article {pmid29444673, year = {2018}, author = {Rocha, GR and Florez Salamanca, EJ and de Barros, AL and Lobo, CIV and Klein, MI}, title = {Effect of tt-farnesol and myricetin on in vitro biofilm formed by Streptococcus mutans and Candida albicans.}, journal = {BMC complementary and alternative medicine}, volume = {18}, number = {1}, pages = {61}, pmid = {29444673}, issn = {1472-6882}, support = {grant #668//PROPe-UNESP/ ; Scholarship #668//PROPe-UNESP/ ; grant #2016/03424-1//São Paulo Research Foundation (FAPESP)/ ; #830071/2000-8//National Counsel of Technological and Scientific Development (CNPq)/ ; }, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Dental Caries/microbiology ; Drug Synergism ; Farnesol/*pharmacology ; Flavonoids/*pharmacology ; Humans ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {BACKGROUND: Dental caries is considered a multifactorial disease, in which microorganisms play an important role. The diet is decisive in the biofilm formation because it provides the necessary resources for cellular growth and exopolysaccharides synthesis. Exopolysaccharides are the main components of the extracellular matrix (ECM). The ECM provides a 3D structure, support for the microorganisms and form diffusion-limited environments (acidic niches) that cause demineralization of the dental enamel. Streptococcus mutans is the main producer of exopolysaccharides. Candida albicans is detected together with S. mutans in biofilms associated with severe caries lesions. Thus, this study aimed to determine the effect of tt-farnesol and myricetin topical treatments on cariogenic biofilms formed by Streptococcus mutans and Candida albicans.

METHODS: In vitro dual-species biofilms were grown on saliva-coated hydroxyapatite discs, using tryptone-yeast extract broth with 1% sucrose (37 °C, 5% CO2). Twice-daily topical treatments were performed with: vehicle (ethanol 15%, negative control), 2 mM myricetin, 4 mM tt-farnesol, myricetin + tt-farnesol, myricetin + tt-farnesol + fluoride (250 ppm), fluoride, and chlorhexidine digluconate (0.12%; positive control). After 67 h, biofilms were evaluated to determine biofilm biomass, microbial population, and water-soluble and -insoluble exopolysaccharides in the ECM.

RESULTS: Only the positive control yielded a reduced quantity of biomass and microbial population, while tt-farnesol treatment was the least efficient in reducing C. albicans population. The combination therapy myricetin + farnesol + fluoride significantly reduced water-soluble exopolysaccharides in the ECM (vs. negative control; p < 0.05; ANOVA one-way, followed by Tukey's test), similarly to the positive control.

CONCLUSIONS: Therefore, the combination therapy negatively influenced an important virulence trait of cariogenic biofilms. However, the concentrations of both myricetin and tt-farnesol should be increased to produce a more pronounced effect to control these biofilms.}, } @article {pmid29443853, year = {2018}, author = {Parsons, M}, title = {CORR Insights®: Chlorhexidine Antiseptic Irrigation Eradicates Staphylococcus epidermidis From Biofilm: An In Vitro Study.}, journal = {Clinical orthopaedics and related research}, volume = {476}, number = {3}, pages = {654-655}, pmid = {29443853}, issn = {1528-1132}, mesh = {*Anti-Infective Agents, Local ; Biofilms ; *Chlorhexidine ; Staphylococcus epidermidis ; }, } @article {pmid29443852, year = {2018}, author = {Schmidt, K and Estes, C and McLaren, A and Spangehl, MJ}, title = {Chlorhexidine Antiseptic Irrigation Eradicates Staphylococcus epidermidis From Biofilm: An In Vitro Study.}, journal = {Clinical orthopaedics and related research}, volume = {476}, number = {3}, pages = {648-653}, pmid = {29443852}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Bacitracin/pharmacology ; Biofilms/*drug effects/growth & development ; Chlorhexidine/*pharmacology ; Dose-Response Relationship, Drug ; Gentamicins/pharmacology ; Microbial Viability/drug effects ; Polymyxins/pharmacology ; Povidone-Iodine/pharmacology ; Sodium Hypochlorite/pharmacology ; Staphylococcus epidermidis/*drug effects/growth & development ; Therapeutic Irrigation/*methods ; Time Factors ; }, abstract = {BACKGROUND: Antiseptic and antibacterial solutions used for intraoperative irrigation are intended to kill bacteria and thereby decrease the incidence of surgical site infections. It is unknown if the concentrations and exposure times of irrigation solutions commonly used for prophylaxis in clean cases (povidone-iodine 0.35% for 3 minutes) are effective against bacteria in biofilm that are present in implant infections. Currently, povidone-iodine (0.35%), chlorhexidine (0.05%), sodium hypochlorite (0.125%), and triple antibacterial solution are all being used off-label for wound irrigation after surgical débridement for orthopaedic infections.

QUESTIONS/PURPOSES: Do commonly used antibacterials and antiseptics kill bacteria in established biofilm at clinically relevant concentrations and exposure times?

METHODS: Staphylococcus epidermidis (ATCC#35984) biofilms were exposed to chlorhexidine (0.025%, 0.05%, and 0.1%), povidone-iodine (0.35%, 1.0%, 3.5%, and 10%), sodium hypochlorite (0.125%, 0.25%, and 0.5%,), and triple antibacterial solution (bacitracin 50,000 U/L, gentamicin 80 mg/L, and polymyxin 500,000 U/L) for 1, 5, and 10 minutes in triplicate. Surviving bacteria were detected by 21-day subculture. Failure to eradicate all bacteria in any of the three replicates was considered to be "not effective" for that respective solution, concentration, and exposure time.

RESULTS: Chlorhexidine 0.05% and 0.1% at all three exposure times, povidone-iodine 10% at all three exposure times, and povidone-iodine 3.5% at 10 minutes only were effective at eradicating S epidermidis from biofilm. All concentrations and all exposure times of sodium hypochlorite and triple antibacterial solution were not effective.

CONCLUSIONS: Chlorhexidine is capable of eradicating S epidermidis from biofilm in vitro in clinically relevant concentrations and exposure times. Povidone-iodine at commonly used concentrations and exposure times, sodium hypochlorite, and triple antibacterial solutions are not.

CLINICAL RELEVANCE: This in vitro study suggests that chlorhexidine may be a more effective irrigation solution for S epidermidis in biofilm than other commonly used solutions, such as povidone-iodine, Dakin's solution, and triple antibiotic solution. Clinical outcomes should be studied to determine the most effective antiseptic agent, concentration, and exposure time when intraoperative irrigation is used in the presence of biofilm.}, } @article {pmid29441819, year = {2018}, author = {Snarr, BD and Howell, PL and Sheppard, DC}, title = {Hoisted by their own petard: do microbial enzymes hold the solution to treating and preventing biofilm infections?.}, journal = {Future microbiology}, volume = {13}, number = {}, pages = {395-398}, doi = {10.2217/fmb-2017-0243}, pmid = {29441819}, issn = {1746-0921}, support = {R33 AI119116/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Infective Agents/metabolism/*pharmacology ; Bacteria/drug effects/*enzymology ; Bacterial Proteins/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Extracellular Matrix/chemistry ; Fungi/drug effects ; Glycoside Hydrolases/metabolism/pharmacology ; Polysaccharide-Lyases/metabolism/pharmacology ; Polysaccharides/metabolism ; }, } @article {pmid29441664, year = {2018}, author = {Souffreau, C and Busschaert, P and Denis, C and Van Wichelen, J and Lievens, B and Vyverman, W and De Meester, L}, title = {A comparative hierarchical analysis of bacterioplankton and biofilm metacommunity structure in an interconnected pond system.}, journal = {Environmental microbiology}, volume = {20}, number = {3}, pages = {1271-1282}, doi = {10.1111/1462-2920.14073}, pmid = {29441664}, issn = {1462-2920}, mesh = {Aquatic Organisms/growth & development ; Bacteria/*growth & development ; *Biodiversity ; Biofilms/*growth & development ; Ecosystem ; Lakes/*microbiology ; Plankton/*growth & development/microbiology ; Ponds/*microbiology ; }, abstract = {It is unknown whether bacterioplankton and biofilm communities are structured by the same ecological processes, and whether they influence each other through continuous dispersal (known as mass effects). Using a hierarchical sampling approach we compared the relative importance of ecological processes structuring the dominant fraction (relative abundance ≥0.1%) of bacterioplankton and biofilm communities from three microhabitats (open water, Nuphar and Phragmites sites) at within- and among-pond scale in a set of 14 interconnected shallow ponds. Our results demonstrate that while bacterioplankton and biofilm communities are highly distinct, a similar hierarchy of ecological processes is acting on them. For both community types, most variation in community composition was determined by pond identity and environmental variables, with no effect of space. The highest β-diversity within each community type was observed among ponds, while microhabitat type (Nuphar, Phragmites, open water) significantly influenced biofilm communities but not bacterioplankton. Mass effects among bacterioplankton and biofilm communities were not detected, as suggested by the absence of within-site covariation of biofilm and bacterioplankton communities. Both biofilm and plankton communities were thus highly structured by environmental factors (i.e., species sorting), with among-lake variation being more important than within-lake variation, whereas dispersal limitation and mass effects were not observed.}, } @article {pmid29441056, year = {2018}, author = {Popović, N and Dinić, M and Tolinački, M and Mihajlović, S and Terzić-Vidojević, A and Bojić, S and Djokić, J and Golić, N and Veljović, K}, title = {New Insight into Biofilm Formation Ability, the Presence of Virulence Genes and Probiotic Potential of Enterococcus sp. Dairy Isolates.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {78}, pmid = {29441056}, issn = {1664-302X}, abstract = {Enterococci have controversial status due to their emerging role in nosocomial infections and transmission of antibiotic resistance genes, while some enterococci strains are used as probiotics for humans and animals and starter cultures in dairy industry. In order to improve our understanding of factors involved in the safe use of enterococci as potential probiotics, the antibiotic susceptibility, virulence and probiotic traits of 75 dairy enterococci isolates belonging to Enterococcus durans (50), En. faecium (15), En. faecalis (6), En. italicus (3), and En. hirae (1) were evaluated. The results revealed that ciprofloxacin resistance and biofilm formation are correlated with isolates originated from Golija mountain (Serbia), while gelatinase activity was more common in isolates from Prigorje region (Croatia), pointing to uncontrolled use of antibiotics and anthropogenic impact on dairy products' microbiota in these regions. The virulence genes were sporadically present in 13 selected dairy enterococci isolates. Interestingly, biofilm formation was correlated with higher ability of strains to reduce the adhesion of E. coli and Salmonella Enteritidis to HT29-MTX cells. To our knowledge this is the first study reporting the presence of the esp gene (previously correlated with pathogenesis) in dairy enterococci isolates, mostly associated with the genes involved in adhesion property. Hence, the results of this study revealed that the virulence genes are sporadically present in dairy isolates and more correlated to adhesion properties and biofilm formation, implicating their role in gut colonization rather than to the virulence traits.}, } @article {pmid29440570, year = {2018}, author = {Petruzzi, B and Briggs, RE and Tatum, FM and Swords, WE and De Castro, C and Molinaro, A and Inzana, TJ}, title = {Erratum for Petruzzi et al., "Capsular Polysaccharide Interferes with Biofilm Formation by Pasteurella multocida Serogroup A".}, journal = {mBio}, volume = {9}, number = {1}, pages = {}, doi = {10.1128/mBio.00176-18}, pmid = {29440570}, issn = {2150-7511}, } @article {pmid29440257, year = {2018}, author = {Kera, K and Nagayama, T and Nanatani, K and Saeki-Yamoto, C and Tominaga, A and Souma, S and Miura, N and Takeda, K and Kayamori, S and Ando, E and Higashi, K and Igarashi, K and Uozumi, N}, title = {Reduction of Spermidine Content Resulting from Inactivation of Two Arginine Decarboxylases Increases Biofilm Formation in Synechocystis sp. Strain PCC 6803.}, journal = {Journal of bacteriology}, volume = {200}, number = {9}, pages = {}, pmid = {29440257}, issn = {1098-5530}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Carboxy-Lyases/*genetics ; Escherichia coli/genetics ; Gene Expression Regulation, Bacterial ; Gene Expression Regulation, Enzymologic ; Gene Silencing ; Spermidine/*analysis ; Synechocystis/enzymology/*genetics ; }, abstract = {The phototropic bacterium Synechocystis sp. strain PCC 6803 is able to adapt its morphology in order to survive in a wide range of harsh environments. Under conditions of high salinity, planktonic cells formed cell aggregates in culture. Further observations using crystal violet staining, confocal laser scanning microscopy, and field emission-scanning electron microscopy confirmed that these aggregates were Synechocystis biofilms. Polyamines have been implicated in playing a role in biofilm formation, and during salt stress the content of spermidine, the major polyamine in Synechocystis, was reduced. Two putative arginine decarboxylases, Adc1 and Adc2, in Synechocystis were heterologously expressed in Escherichia coli and purified. Adc2 had high arginine decarboxylase activity, whereas Adc1 was much less active. Disruption of the adc genes in Synechocystis resulted in decreased spermidine content and formation of biofilms even under nonstress conditions. Based on the characterization of the adc mutants, Adc2 was the major arginine decarboxylase whose activity led to inhibition of biofilm formation, and Adc1 contributed only minimally to the process of polyamine synthesis. Taken together, in Synechocystis the shift from planktonic lifestyle to biofilm formation was correlated with a decrease in intracellular polyamine content, which is the inverse relationship of what was previously reported in heterotroph bacteria.IMPORTANCE There are many reports concerning biofilm formation in heterotrophic bacteria. In contrast, studies on biofilm formation in cyanobacteria are scarce. Here, we report on the induction of biofilm formation by salt stress in the model phototrophic bacterium Synechocystis sp. strain PCC 6803. Two arginine decarboxylases (Adc1 and Adc2) possess function in the polyamine synthesis pathway. Inactivation of the adc1 and adc2 genes leads to biofilm formation even in the absence of salt. The shift from planktonic culture to biofilm formation is regulated by a decrease in spermidine content in Synechocystis This negative correlation between biofilm formation and polyamine content, which is the opposite of the relationship reported in other bacteria, is important not only in autotrophic but also in heterotrophic bacteria.}, } @article {pmid29438671, year = {2018}, author = {Draughn, GL and Milton, ME and Feldmann, EA and Bobay, BG and Roth, BM and Olson, AL and Thompson, RJ and Actis, LA and Davies, C and Cavanagh, J}, title = {The Structure of the Biofilm-controlling Response Regulator BfmR from Acinetobacter baumannii Reveals Details of Its DNA-binding Mechanism.}, journal = {Journal of molecular biology}, volume = {430}, number = {6}, pages = {806-821}, pmid = {29438671}, issn = {1089-8638}, support = {R01 GM055769/GM/NIGMS NIH HHS/United States ; S10 RR027139/RR/NCRR NIH HHS/United States ; }, mesh = {Acinetobacter baumannii/drug effects/genetics/*metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*chemistry/genetics/metabolism ; Base Sequence ; Biofilms/drug effects/*growth & development ; Cloning, Molecular ; Crystallography, X-Ray ; DNA-Binding Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Models, Molecular ; Phosphorylation ; Promoter Regions, Genetic ; Protein Conformation ; }, abstract = {The rise of drug-resistant bacterial infections coupled with decreasing antibiotic efficacy poses a significant challenge to global health care. Acinetobacter baumannii is an insidious, emerging bacterial pathogen responsible for severe nosocomial infections aided by its ability to form biofilms. The response regulator BfmR, from the BfmR/S two-component system, is the master regulator of biofilm initiation in A. baumannii and is a tractable therapeutic target. Here we present the structure of A. baumannii BfmR using a hybrid approach combining X-ray crystallography, nuclear magnetic resonance spectroscopy, chemical crosslinking mass spectrometry, and molecular modeling. We also show that BfmR binds the previously proposed bfmRS promoter sequence with moderate affinity. While BfmR shares many traits with other OmpR/PhoB family response regulators, some unusual properties were observed. Most importantly, we observe that when phosphorylated, BfmR binds this promoter sequence with a lower affinity than when not phosphorylated. All other OmpR/PhoB family members studied to date show an increase in DNA-binding affinity upon phosphorylation. Understanding the structural and biochemical mechanisms of BfmR will aid in the development of new antimicrobial therapies.}, } @article {pmid29436026, year = {2018}, author = {Nunes Filho, A and Aires, MM and Braz, DC and Hinrichs, R and Macedo, AJ and Alves, C}, title = {Titanium Surface Chemical Composition Interferes in the Pseudomonas aeruginosa Biofilm Formation.}, journal = {Artificial organs}, volume = {42}, number = {2}, pages = {193-199}, doi = {10.1111/aor.12983}, pmid = {29436026}, issn = {1525-1594}, mesh = {Alloys/*chemistry ; Bacterial Adhesion ; Biofilms/*growth & development ; Humans ; Nanostructures/*chemistry ; Pseudomonas Infections/prevention & control ; Pseudomonas aeruginosa/*physiology ; Surface Properties ; Titanium/*chemistry ; Wettability ; }, abstract = {Bacterial adhesion on three different surfaces: untreated Ti, plasma nitriding, and plasma carbonitriding Ti substrates were investigated. The samples were placed in bacterial cultures of Pseudomonas aeruginosa to assess biofilm formation. The correlation between the amount of bacteria attached to the surface after a lapse of time with nanotopography and physicochemical properties was performed. TiN showed the highest capacity to avoid bacterial adhesion, while presenting intermediate roughness and wettability. Although the surface of TiCN had the highest surface roughness and low contact angle (high wettability), bacterial adhesion was intermediate on this sample. Untreated Ti, even though presenting a smooth surface and low wettability, had the highest tendency to form biofilms.}, } @article {pmid29434393, year = {2018}, author = {Rajasekharan, SK and Lee, JH and Zhao, Y and Lee, J}, title = {The Mycotoxin Zearalenone Hinders Candida albicans Biofilm Formation and Hyphal Morphogenesis.}, journal = {Indian journal of microbiology}, volume = {58}, number = {1}, pages = {19-27}, pmid = {29434393}, issn = {0046-8991}, abstract = {Yeast-mold mycobiota inhabit several natural ecosystems, in which symbiotic relationships drive strategic pathoadaptation. Mycotoxins are metabolites produced by diverse mycotoxigenic fungi as a defense against yeasts, though at times yeasts secrete enzymes that degrade, detoxify, or bio-transform mycotoxins. The present study is focused on the in vitro inhibitory effects of zearalenone (ZEN), a F2 mycotoxin produced by several Fusarium and Gibberella species, on different microbial strains. ZEN exhibited no effect on the planktonic growth or biofilms of several Gram positive and negative bacteria at the tested concentrations. Remarkably, Candida albicans biofilm formation and hyphal morphogenesis were significantly inhibited when treated with 100 µg/mL of ZEN. Likewise, ZEN proficiently disrupted pre-formed C. albicans biofilms without disturbing planktonic cells. Furthermore, these inhibitions were confirmed by crystal violet staining and XTT reduction assays and by confocal and scanning electron microscopy. In an in vivo model, ZEN significantly suppressed C. albicans infection in the nematode Caenorhabditis elegans. The study reports the in vitro antibiofilm efficacy of ZEN against C. albicans strains, and suggests mycotoxigenic fungi participate in asymmetric competitive interactions, such as, amensalism or antibiosis, rather than commensal interactions with C. albicans, whereby mycotoxins secreted by fungi destroy C. albicans biofilms.}, } @article {pmid29433269, year = {2018}, author = {Chuah, LO and Shamila Syuhada, AK and Mohamad Suhaimi, I and Farah Hanim, T and Rusul, G}, title = {Genetic relatedness, antimicrobial resistance and biofilm formation of Salmonella isolated from naturally contaminated poultry and their processing environment in northern Malaysia.}, journal = {Food research international (Ottawa, Ont.)}, volume = {105}, number = {}, pages = {743-751}, doi = {10.1016/j.foodres.2017.11.066}, pmid = {29433269}, issn = {1873-7145}, mesh = {Biofilms/drug effects/*growth & development ; DNA, Bacterial/*genetics ; Drug Resistance, Multiple, Bacterial/*genetics ; Electrophoresis, Gel, Pulsed-Field ; Food Handling/*methods ; Food Microbiology/*methods ; Gene Expression Profiling ; Genotype ; Malaysia ; Meat Products/*microbiology ; Microbial Sensitivity Tests ; *Mutation ; Phenotype ; Polymerase Chain Reaction ; Poultry Products/*microbiology ; Salmonella enterica/drug effects/*genetics/*growth & development/isolation & purification ; }, abstract = {We investigated the genetic relatedness, antibiotic resistance and biofilm-producing ability of 114 strains of Salmonella, belonged to three serotypes (Corvallis, Brancaster and Albany), isolated from naturally contaminated poultry and their environment in wet markets and smale-scale processing plant from northern Malaysia. Pulsed-field gel electrophoresis revealed that Salmonella strains isolated from various wet markets were clonally related, suggesting the widespread dissemination of these three serotypes in northern Malaysia. All except one strain of Salmonella were resistant to more than two classes of antibiotics, hence regarded as multidrug resistant (MDR). Resistance to sulphonamide (96.5%), ampicillin (89.5%), tetracycline (85.1%), chloramphenicol (75.4%), trimethoprim (68.4%), trimethoprim-sulfamethoxazole (67.5%), streptomycin (58.8%) and nalidixic acid (44.4%) were observed. Resistance determinants, floR, cmlA, tetA, tetB, tetG, temB, blaPSE-1, sul1, sul2, qnrA, qnrS, strA and aadA were detected by PCR among MDR Salmonella strains. Seventy-six strains (66.7%) harboured class-I integrons. The gene cassettes identified were dfrA1, dfrA12, aadA2 and an open reading frame orfC with unknown function. All Salmonella strains produced biofilm and 69.3% of them were strong biofilm-producers. Our findings suggested that most likely, persistent Salmonella colonises various sites in the processing environment by producing biofilm, which leads to their widespread dissemination in wet markets located in northern Malaysia.}, } @article {pmid29433078, year = {2018}, author = {Carrel, M and Morales, VL and Beltran, MA and Derlon, N and Kaufmann, R and Morgenroth, E and Holzner, M}, title = {Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development.}, journal = {Water research}, volume = {134}, number = {}, pages = {280-291}, doi = {10.1016/j.watres.2018.01.059}, pmid = {29433078}, issn = {1879-2448}, mesh = {Biofilms/*growth & development ; Hydrodynamics ; Porosity ; Rheology ; Stress, Mechanical ; X-Ray Microtomography ; }, abstract = {This study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36 h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm. A local analysis revealed wide distributions of wall shear stresses and concentration boundary layer thicknesses. The spatial distribution of the biofilm patches uncovered that the wall shear stresses controlled the biofilm development. Neither external nor internal mass transfer limitations were noticeable in the considered system, consistent with the excess supply of nutrient and electron acceptors. The wall shear stress remained constant in the vicinity of the biofilm but increased substantially elsewhere.}, } @article {pmid29432487, year = {2018}, author = {De, S and Kaus, K and Sinclair, S and Case, BC and Olson, R}, title = {Structural basis of mammalian glycan targeting by Vibrio cholerae cytolysin and biofilm proteins.}, journal = {PLoS pathogens}, volume = {14}, number = {2}, pages = {e1006841}, pmid = {29432487}, issn = {1553-7374}, support = {T32 GM008271/GM/NIGMS NIH HHS/United States ; U54 GM062116/GM/NIGMS NIH HHS/United States ; R24 GM098791/GM/NIGMS NIH HHS/United States ; R15 AI101977/NH/NIH HHS/United States ; R15 AI101977/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Binding Sites ; *Biofilms ; Blood Cells/metabolism ; Crystallography, X-Ray ; Cytotoxins/chemistry/genetics/*metabolism ; Kinetics ; *Models, Molecular ; Mutation ; Peptide Fragments/chemistry/genetics/metabolism ; Perforin/chemistry/genetics/*metabolism ; Polysaccharides/chemistry/*metabolism ; Protein Interaction Domains and Motifs ; Rabbits ; Receptors, Cell Surface/antagonists & inhibitors/chemistry/*metabolism ; Recombinant Fusion Proteins/chemistry/metabolism ; Sequence Alignment ; Sequence Homology, Amino Acid ; Vibrio cholerae/immunology/pathogenicity/*physiology ; Virulence Factors/chemistry/genetics/metabolism ; }, abstract = {Vibrio cholerae is an aquatic gram-negative microbe responsible for cholera, a pandemic disease causing life-threatening diarrheal outbreaks in populations with limited access to health care. Like most pathogenic bacteria, V. cholerae secretes virulence factors to assist colonization of human hosts, several of which bind carbohydrate receptors found on cell-surfaces. Understanding how pathogenic virulence proteins specifically target host cells is important for the development of treatment strategies to fight bacterial infections. Vibrio cholerae cytolysin (VCC) is a secreted pore-forming toxin with a carboxy-terminal β-prism domain that targets complex N-glycans found on mammalian cell-surface proteins. To investigate glycan selectivity, we studied the VCC β-prism domain and two additional β-prism domains found within the V. cholerae biofilm matrix protein RbmC. We show that the two RbmC β-prism domains target a similar repertoire of complex N-glycan receptors as VCC and find through binding and modeling studies that a branched pentasaccharide core (GlcNAc2-Man3) represents the likely footprint interacting with these domains. To understand the structural basis of V. cholerae β-prism selectivity, we solved high-resolution crystal structures of fragments of the pentasaccharide core bound to one RbmC β-prism domain and conducted mutagenesis experiments on the VCC toxin. Our results highlight a common strategy for cell-targeting utilized by both toxin and biofilm matrix proteins in Vibrio cholerae and provide a structural framework for understanding the specificity for individual receptors. Our results suggest that a common strategy for disrupting carbohydrate interactions could affect multiple virulence factors produced by V. cholerae, as well as similar β-prism domains found in other vibrio pathogens.}, } @article {pmid29431716, year = {2018}, author = {Leyva-Díaz, JC and Rodríguez-Sánchez, A and González-López, J and Poyatos, JM}, title = {Effect of salinity variation on the autotrophic kinetics of the start-up of a membrane bioreactor and hybrid moving bed biofilm reactor-membrane bioreactor at low hydraulic retention time.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {3-4}, pages = {714-720}, doi = {10.2166/wst.2017.585}, pmid = {29431716}, issn = {0273-1223}, mesh = {Ammonium Compounds/metabolism ; Biofilms ; Biomass ; *Bioreactors ; Electric Conductivity ; Kinetics ; Membranes, Artificial ; Nitrogen/metabolism ; *Salinity ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Pollutants, Chemical/*metabolism ; }, abstract = {A membrane bioreactor (MBR) and a hybrid moving bed biofilm reactor-membrane bioreactor (hybrid MBBR-MBR) for municipal wastewater treatment were studied to determine the effect of salinity on nitrogen removal and autotrophic kinetics. The biological systems were analyzed during the start-up phase with a hydraulic retention time (HRT) of 6 h, total biomass concentration of 2,500 mg L[-1] in the steady state, and electric conductivities of 1.05 mS cm[-1] for MBR and hybrid MBBR-MBR working under regular salinity and conductivity variations of 1.2-6.5 mS cm[-1] for MBR and hybrid MBBR-MBR operating at variable salinity. The variable salinity affected the autotrophic biomass, which caused a reduction of the nitrogen degradation rate, an increase of time to remove ammonium from municipal wastewater and longer duration of the start-up phase for the MBR and hybrid MBBR-MBR.}, } @article {pmid29431703, year = {2018}, author = {Patry, B and Boutet, É and Baillargeon, S and Lessard, P}, title = {Solid-liquid separation of an effluent produced by a fixed media biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {3-4}, pages = {589-596}, doi = {10.2166/wst.2017.575}, pmid = {29431703}, issn = {0273-1223}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Particle Size ; Temperature ; Waste Disposal, Fluid/*methods ; }, abstract = {An experimental study dedicated to the characterization of the settleability of solids produced in immersed fixed media biofilm reactors has been carried out. The influence of operating temperature (0.1 to 16 °C) and surface organic loading rate (OLR) (0.4 to 10 g of soluble carbonaceous BOD5 per m[2] of media per day) on settleable solids quantities, particle size distributions (PSD) as well as flocs morphology was evaluated. Results have shown that the OLR has no statistically significant influence on the settleability of the suspended solids. However, the operating temperature was identified as a factor that significantly influences the settling potential. The highest operating temperatures (14-16 °C) were related to the worst settling performances. On the other hand, the best settling performances were observed at intermediate operating temperatures (around 10 °C). The latter conditions were also associated with the largest fractions of large particles (>100 μm) in the effluent. Differences in PSD were found to be well correlated with settling performances. Part of the performance results variability which cannot be explained by differences in PSD can potentially be attributed to differences in flocs morphology (compactness).}, } @article {pmid29430962, year = {2018}, author = {Braga, AS and Pires, JG and Magalhães, AC}, title = {Effect of a mouthrinse containing Malva sylvestris on the viability and activity of microcosm biofilm and on enamel demineralization compared to known antimicrobials mouthrinses.}, journal = {Biofouling}, volume = {34}, number = {3}, pages = {252-261}, doi = {10.1080/08927014.2018.1428957}, pmid = {29430962}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Chlorhexidine/pharmacology ; Dental Enamel/*microbiology ; Drug Combinations ; Humans ; Lactobacillus/drug effects ; Malva/*chemistry ; Mouthwashes/chemistry/*pharmacology ; Salicylates/pharmacology ; Saliva ; Streptococcus/drug effects ; Streptococcus mutans/drug effects ; Terpenes/pharmacology ; Tooth Demineralization/microbiology/*prevention & control ; }, abstract = {The purpose of this study was to evaluate the antimicrobial (anti-biofilm) and anti-caries (enamel demineralization prevention) effects of Malva sylvestris (Malvatricin[®] Plus) compared with known antimicrobial mouthrinses. Microcosm biofilm was produced on enamel, using inoculum from pooled human saliva mixed with McBain saliva (0.2% sucrose) for 14 days. The biofilm was treated with mouthrinses for 1 min day[-1]. Oral-B[®] Complete, Listerine[®] Zero and Malvatricin[®] Plus had the greatest effect on the reduction of biofilm viability (p < 0.0001). On the other hand, lactic acid production was reduced significantly with PerioGard[®], Noplak[®] Max and Listerine[®] Zero compared with the control (p < 0.0001). No significant differences were found among the mouthrinses with respect to the colony-forming unit counting (total microorganisms, total streptococci, mutans streptococci and lactobacilli) and extracellular polysaccharide production. Enamel demineralization was reduced significantly with PerioGard[®], Noplak[®] Max and Malvatricin[®] Plus compared with the control (p < 0.0001). Malva sylvestris has a comparable anti-caries effect to chlorhexidine mouthrinses.}, } @article {pmid29430138, year = {2018}, author = {Nedumgottil, BM}, title = {Relative presence of Streptococcus mutans, Veillonella atypica, and Granulicatella adiacens in biofilm of complete dentures.}, journal = {Journal of Indian Prosthodontic Society}, volume = {18}, number = {1}, pages = {24-28}, pmid = {29430138}, issn = {0972-4052}, abstract = {AIMS AND OBJECTIVE: Oral biofilms in denture wearers are populated with a large number of bacteria, a few of which have been associated with medical conditions such as sepsis and infective endocarditis (IE). The present study was designed to investigate the relative presence of pathogenic bacteria in biofilms of denture wearers specifically those that are associated with IE.

METHODS: Biofilm samples from 88 denture wearers were collected and processed to extract total genomic DNA. Eight of these samples were subjected to 16S rRNA gene sequencing analysis to first identify the general bacterial occurrence pattern. This was followed by species-specific quantitative polymerase chain reaction (qPCR) on entire batch of 88 samples to quantify the relative copy numbers of IE-associated pathogens.

RESULTS: 16S rRNA gene analysis of eight biofilm samples identified bacteria from Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, and Fusobacteria species. Interestingly, Streptococcus mutans, Veillonella atypica, and Granulicatella adiacens from Firmicutes, all known to be associated with early-onset sepsis and IE was present in five of eight biofilm samples. The other three samples carried bacteria from genus Proteobacteria with Neisseria flava and Neisseria mucosa, which are known to be commensals, as dominant species. Species-specific qPCR of S. mutans V. atypica, and G. adiacens on 88 biofilm DNA samples identified the presence of S. mutans in 83%, V. atypica in 79%, and G. adiacens in 76% of samples.

CONCLUSION: The findings from the present study demonstrate co-occurrence of S. mutans, V. atypica, and G. adiacens in a majority of denture wearers, which is clinically significant as elderly patients with compromised immune system are more prone to develop IE. To the best of our knowledge, the co-occurrence of S. mutans, V. atypica, and G. adiacens is being reported for the first time in biofilms of denture wearers.}, } @article {pmid29429115, year = {2018}, author = {Costa, FN and Belo, NO and Costa, EA and Andrade, GI and Pereira, LS and Carvalho, IA and Santos, RL}, title = {Frequency of enterotoxins, toxic shock syndrome toxin-1, and biofilm formation genes in Staphylococcus aureus isolates from cows with mastitis in the Northeast of Brazil.}, journal = {Tropical animal health and production}, volume = {50}, number = {5}, pages = {1089-1097}, pmid = {29429115}, issn = {1573-7438}, mesh = {Amoxicillin/administration & dosage ; Animals ; Bacterial Toxins/*genetics ; *Biofilms ; Brazil ; Cattle ; Enterotoxins/*genetics ; Female ; Gentamicins/administration & dosage ; Mastitis, Bovine/*microbiology ; Norfloxacin/administration & dosage ; Staphylococcal Infections/*veterinary ; Staphylococcus aureus/*genetics/isolation & purification ; Superantigens/*genetics ; Virulence ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus is among the microorganisms more frequently associated with subclinical bovine mastitis. S. aureus may produce several virulence factors. This study aimed at determining the frequency of virulence factors such as enterotoxins, toxic shock syndrome toxin 1, and ica adhesion genes. In addition, we assessed antimicrobial drug resistance in S. aureus isolated from clinical and subclinical cases of mastitis. A total of 88 cows with clinical or subclinical mastitis were sampled, resulting in 38 S. aureus isolates, from which 25 (65.78%) carried toxin genes, including seb, sec, sed, tst, and icaD adhesion gene. These S. aureus isolates belong to 21 ribotypes and three S. aureus strains belonged to the same ribotype producing ica adhesion gene. Approximately 90% of S. aureus strains obtained in our study demonstrated multiple resistance to different antimicrobial agents. The most efficacious antimicrobial agents against the isolates were gentamicin, amoxicillin, and norfloxacin. Gentamicin was the most efficacious agent inhibiting 78.95% of the S. aureus isolates. The least efficacious were penicillin, streptomycin, and ampicillin. Our results can help in understanding the relationship between virulence factors and subclinical mastitis caused by S. aureus. Further research about diversity of S. aureus isolates and genes responsible for the pathogenicity of subclinical mastitis is essential.}, } @article {pmid29429082, year = {2018}, author = {Jani, S}, title = {Visualizing Chemoattraction of Planktonic Cells to a Biofilm.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1729}, number = {}, pages = {61-69}, doi = {10.1007/978-1-4939-7577-8_6}, pmid = {29429082}, issn = {1940-6029}, mesh = {Biofilms/*growth & development ; Cellular Microenvironment ; Chemotaxis ; Escherichia coli/*physiology ; Escherichia coli Proteins/metabolism ; Homoserine/*analogs & derivatives/metabolism ; Lactones/*metabolism ; Microscopy, Confocal ; Plankton/*physiology ; }, abstract = {Bacterial chemotaxis in response to continuous chemical gradients has been extensively studied at the individual cell and population levels using a variety of well-established in vitro methods (Englert et al., Microfluidic techniques for the analysis of bacterial chemotaxis. Methods Mol Biol 571:1-23, 2009). In nature, bacteria are surrounded by heterogeneous chemical gradients; hence, it is essential to understand chemotaxis behavior under such conditions. Here, we describe a setup that allows visualization of the chemotaxis response of motile cells to the complex microenvironment of a biofilm maintained under static conditions. The biofilm is separated from the motile cells by a semi-permeable membrane. Cells swimming toward the biofilm are captured on the membrane and imaged using confocal laser scanning microscopy (CLSM). Chemotaxis toward specific molecules produced by the biofilm, such as autoinducer-2 (AI-2), can be studied using this setup. This system can be adapted to study chemotaxis toward poly-species biofilms, or even mammalian cells.}, } @article {pmid29428742, year = {2018}, author = {Ye, Y and Ling, N and Gao, J and Zhang, M and Zhang, X and Tong, L and Ou, D and Wang, Y and Zhang, J and Wu, Q}, title = {Short communication: Roles of outer membrane protein W (OmpW) on survival and biofilm formation of Cronobacter sakazakii under neomycin sulfate stress.}, journal = {Journal of dairy science}, volume = {101}, number = {4}, pages = {2927-2931}, doi = {10.3168/jds.2017-13517}, pmid = {29428742}, issn = {1525-3198}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cronobacter sakazakii/genetics/*physiology ; Gentian Violet/chemistry ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Mutation ; Neomycin/*pharmacology ; Staining and Labeling ; }, abstract = {Cronobacter sakazakii is associated with severe infections including sepsis, neonatal meningitis, and necrotizing enterocolitis. Antibiotic resistance in Cronobacter species has been documented in recent years, but the genes involved in resistance in Cronobacter strains are poorly understood. In this study, we determined the role of outer membrane protein W (OmpW) on survival rates, morphologic changes, and biofilm formation between wild type (WT) and an OmpW mutant strain (ΔOmpW) under neomycin sulfate stress. Results indicated that the survival rates of ΔOmpW were significantly reduced after half minimum inhibitory concentration (½ MIC) treatment compared with the WT strain. Filamentation of C. sakazakii cells was observed after ½ MIC treatment in WT and ΔOmpW, and morphologic injury, including cell disruption and leakage of cells, was more predominant in ΔOmpW. Under ½ MIC stress, the biofilms of WT and ΔOmpW were significantly decreased, but decreasing rates of biofilm formation in mutant strain were more predominant compared with WT strain. This is the first report to determine the role of OmpW on survival, morphological changes, and biofilm formation in C. sakazakii under neomycin sulfate stress. The findings indicated that OmpW contributed to survival and reduction of morphological injury under neomycin sulfate stress. In addition, enhancing biofilm formation in ΔOmpW may be an alternative advantage for adaptation to neomycin sulfate stress.}, } @article {pmid29427863, year = {2018}, author = {Zhang, P and Qu, Y and Feng, Y and Liu, J}, title = {The influence of the filtration membrane air-cathode biofilm on wastewater treatment.}, journal = {Bioresource technology}, volume = {256}, number = {}, pages = {17-21}, doi = {10.1016/j.biortech.2018.01.124}, pmid = {29427863}, issn = {1873-2976}, mesh = {Bacteria ; Bioelectric Energy Sources ; *Biofilms ; Bioreactors ; Electrodes ; *Wastewater ; }, abstract = {The aim of this work was to evaluate the influence of FMA biofilm on nutrient removal through the filtration membrane air-cathode (FMA) replacement test. The result showed that the biofilm accounted for only 29.9% of the COD removal, while 82.9% of the TN removal can be due to the contribution of the FMA biofilm. The microbial community analysis showed that most of the primary genus in the FMA biofilm were TN removal related bacteria. This quantitative determination of the FMA biofilm influence on COD and TN removal would promote the further optimization of the MFC reactor with FMA for higher wastewater treatment efficiency.}, } @article {pmid29427638, year = {2018}, author = {Li, Q and Li, Z and Li, X and Xia, L and Zhou, X and Xu, Z and Shao, J and Shen, Q and Zhang, R}, title = {FtsEX-CwlO regulates biofilm formation by a plant-beneficial rhizobacterium Bacillus velezensis SQR9.}, journal = {Research in microbiology}, volume = {169}, number = {3}, pages = {166-176}, doi = {10.1016/j.resmic.2018.01.004}, pmid = {29427638}, issn = {1769-7123}, mesh = {ATP-Binding Cassette Transporters/*genetics/metabolism ; Bacillus/*physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Metabolic Networks and Pathways ; Models, Biological ; Mutation ; N-Acetylmuramoyl-L-alanine Amidase/metabolism ; Phenotype ; Plant Roots/*microbiology ; Protein Binding ; *Rhizosphere ; }, abstract = {Bacillus velezensis strain SQR9 is a well-investigated rhizobacterium with an outstanding ability to colonize roots, enhance plant growth and suppress soil-borne diseases. The recognition that biofilm formation by plant-beneficial bacteria is crucial for their root colonization and function has resulted in increased interest in understanding molecular mechanisms related to biofilm formation. Here, we report that the gene ftsE, encoding the ATP-binding protein of an FtsEX ABC transporter, is required for efficient SQR9 biofilm formation. FtsEX has been reported to regulate the atolysin CwlO. We provided evidence that FtsEX-CwlO was involved in the regulation of SQR9 biofilm formation; however, this effect has little to do with CwlO autolysin activity. We propose that regulation of biofilm formation by CwlO was exerted through the spo0A pathway, since transcription of spo0A cascade genes was altered and their downstream extracellular matrix genes were downregulated in SQR9 ftsE/cwlO deletion mutants. CwlO was also shown to interact physically with KinB/KinD. CwlO may therefore interact with KinB/KinD to interfere with the spo0A pathway. This study revealed that FtsEX-CwlO plays a previously undiscovered regulatory role in biofilm formation by SQR9 that may enhance root colonization and plant-beneficial functions of SQR9 and other beneficial rhizobacteria as well.}, } @article {pmid29427424, year = {2018}, author = {Zhou, X and Zhang, N and Xia, L and Li, Q and Shao, J and Shen, Q and Zhang, R}, title = {ResDE Two-Component Regulatory System Mediates Oxygen Limitation-Induced Biofilm Formation by Bacillus amyloliquefaciens SQR9.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {8}, pages = {}, pmid = {29427424}, issn = {1098-5336}, mesh = {Bacillus amyloliquefaciens/genetics/growth & development/*physiology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression ; Oxygen/*metabolism ; Proteome/genetics/*metabolism ; }, abstract = {Efficient biofilm formation and root colonization capabilities facilitate the ability of beneficial plant rhizobacteria to promote plant growth and antagonize soilborne pathogens. Biofilm formation by plant-beneficial Bacillus strains is triggered by environmental cues, including oxygen deficiency, but the pathways that sense these environmental signals and regulate biofilm formation have not been thoroughly elucidated. In this study, we showed that the ResDE two-component regulatory system in the plant growth-promoting rhizobacterium Bacillus amyloliquefaciens strain SQR9 senses the oxygen deficiency signal and regulates biofilm formation. ResE is activated by sensing the oxygen limitation-induced reduction of the NAD[+]/NADH pool through its PAS domain, stimulating its kinase activity, and resulting in the transfer of a phosphoryl group to ResD. The phosphorylated ResD directly binds to the promoter regions of the qoxABCD and ctaCDEF operons to improve the biosynthesis of terminal oxidases, which can interact with KinB to activate biofilm formation. These results not only revealed the novel regulatory function of the ResDE two-component system but also contributed to the understanding of the complicated regulatory network governing Bacillus biofilm formation. This research may help to enhance the root colonization and the plant-beneficial efficiency of SQR9 and other Bacillus rhizobacteria used in agriculture.IMPORTANCEBacillus spp. are widely used as bioinoculants for plant growth promotion and disease suppression. The exertion of their plant-beneficial functions is largely dependent on their root colonization, which is closely related to their biofilm formation capabilities. On the other hand, Bacillus is the model bacterium for biofilm study, and the process and molecular network of biofilm formation are well characterized (B. Mielich-Süss and D. Lopez, Environ Microbiol 17:555-565, 2015, https://doi.org/10.1111/1462-2920.12527; L. S. Cairns, L. Hobley, and N. R. Stanley-Wall, Mol Microbiol 93:587-598, 2014, https://doi.org/10.1111/mmi.12697; H. Vlamakis, C. Aguilar, R. Losick, and R. Kolter, Genes Dev 22:945-953, 2008, https://doi.org/10.1101/gad.1645008; S. S. Branda, A. Vik, L. Friedman, and R. Kolter, Trends Microbiol 13:20-26, 2005, https://doi.org/10.1016/j.tim.2004.11.006; C. Aguilar, H. Vlamakis, R. Losick, and R. Kolter, Curr Opin Microbiol 10:638-643, 2007, https://doi.org/10.1016/j.mib.2007.09.006; S. S. Branda, J. E. González-Pastor, S. Ben-Yehuda, R. Losick, and R. Kolter, Proc Natl Acad Sci U S A 98:11621-11626, 2001, https://doi.org/10.1073/pnas.191384198). However, the identification and sensing of environmental signals triggering Bacillus biofilm formation need further research. Here, we report that the oxygen deficiency signal inducing Bacillus biofilm formation is sensed by the ResDE two-component regulatory system. Our results not only revealed the novel regulatory function of the ResDE two-component regulatory system but also identified the sensing system of a biofilm-triggering signal. This knowledge can help to enhance the biofilm formation and root colonization of plant-beneficial Bacillus strains and also provide new insights of bacterial biofilm formation regulation.}, } @article {pmid29427422, year = {2018}, author = {Olson, ML and Jayaraman, A and Kao, KC}, title = {Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {8}, pages = {}, pmid = {29427422}, issn = {1098-5336}, mesh = {Antifungal Agents/*pharmacology ; *Biofilms/growth & development ; Candida albicans/pathogenicity/*physiology ; Candida glabrata/pathogenicity/*physiology ; *Coculture Techniques ; Gene Expression/physiology ; Genes, Fungal/physiology ; Microbial Sensitivity Tests ; Virulence/genetics ; }, abstract = {Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species-Candida albicans and Candida glabrata-are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans/C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans/C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans/C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner.IMPORTANCECandida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in pathogenesis. During the course of an infection, the prevalence of each Candida species may change over time due to differences in metabolism and in the resistance of each species to antifungal therapies. Therefore, it is necessary to understand the dynamics between C. albicans and C. glabrata in coculture to develop better therapeutic strategies against Candida infections. Existing in vitro work has focused on understanding how an equal-part culture of C. albicans and C. glabrata impacts biofilm formation and pathogenesis. What is not understood, and what is investigated in this work, is how the composition of Candida species in coculture impacts overall biofilm formation, virulence gene expression, and the therapeutic treatment of biofilms.}, } @article {pmid29427006, year = {2018}, author = {Alayande, AB and Aung, MM and Kim, IS}, title = {Correlation Between Quorum Sensing Signal Molecules and Pseudomonas aeruginosa's Biofilm Development and Virulency.}, journal = {Current microbiology}, volume = {75}, number = {7}, pages = {787-793}, pmid = {29427006}, issn = {1432-0991}, support = {18IFIP-B087389-05//Ministry of Land, Infrastructure, and Transport of Korean government./ ; }, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; *Biofilms ; Humans ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/growth & development/pathogenicity/*physiology ; Pyocyanine/metabolism ; *Quorum Sensing ; Virulence ; Virulence Factors/metabolism ; }, abstract = {Bacteria, when adhered to a substratum, can form biofilms. Nevertheless, many factors dictate biofilm formation and virulence factor production, including a response by the bacteria to their surroundings. This system is referred to as Quorum sensing (QS) also known as cell-cell communication. Pseudomonas aeruginosa is an infection causing agent in immune-compromised patients, it uses acyl-homoserine lactone (AHL) to coordinate its QS systems. In this work, the connection between some members of AHL produced by P. aeruginosa PAO1 and its biofilm development and the production of virulence factor was investigated. It was discovered that N-butanoyl-homoserine lactone (C4-HSL) and N-hexanoyl-L-homoserine lactone (C6-HSL) perform a more consequential and eminent function in the biofilm maturation and virulence factor production while N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL) plays a role in biofilm initiation. Because QS has been reported to be required for biofilm development and pathogenesis of P. aeruginosa, the results of this work have great importance and significance for the design of strategies for the control and prevention of biofilms.}, } @article {pmid29426873, year = {2018}, author = {Kong, C and Chee, CF and Richter, K and Thomas, N and Abd Rahman, N and Nathan, S}, title = {Suppression of Staphylococcus aureus biofilm formation and virulence by a benzimidazole derivative, UM-C162.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {2758}, pmid = {29426873}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Benzimidazoles/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans/microbiology ; *Cross Infection/drug therapy/microbiology ; Gene Expression Profiling ; *Staphylococcal Infections/drug therapy/microbiology ; *Staphylococcus aureus/drug effects/genetics/pathogenicity ; Virulence/drug effects/genetics ; Virulence Factors/genetics ; }, abstract = {Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans - S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.}, } @article {pmid29424664, year = {2018}, author = {Liu, W and Sun, Y and Shen, R and Dang, X and Liu, X and Sui, F and Li, Y and Zhang, Z and Alexandre, G and Elmerich, C and Xie, Z}, title = {A Chemotaxis-Like Pathway of Azorhizobium caulinodans Controls Flagella-Driven Motility, Which Regulates Biofilm Formation, Exopolysaccharide Biosynthesis, and Competitive Nodulation.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {31}, number = {7}, pages = {737-749}, doi = {10.1094/MPMI-12-17-0290-R}, pmid = {29424664}, issn = {0894-0282}, mesh = {Azorhizobium/*physiology ; Biofilms/*growth & development ; Chemotaxis/*physiology ; Flagella/*physiology ; Movement ; Plant Root Nodulation/*physiology ; Plant Stems/microbiology ; Polysaccharides, Bacterial/*biosynthesis ; Sesbania/microbiology ; }, abstract = {The genome of the Azorhizobium caulinodans ORS571 contains a unique chemotaxis gene cluster (che) including five chemotaxis genes: cheA, cheW, cheY1, cheB, and cheR. Analysis of the role of the chemotaxis cluster of A. caulinodans using deletion mutant strains revealed that CheA or the Che signaling pathway controls chemotaxis behavior and flagella-driven motility and plays important roles in formation of biofilms and production of extracellular polysaccharides (EPS). Furthermore, the deletion mutants (ΔcheA and ΔcheA-R) were defective in competitive adsorption and colonization on the root surface of host plants. In addition, a functional CheA or Che pathway promoted competitive nodulation on roots and stems. Interestingly, a nonflagellated mutant, ΔfliM, displayed a phenotype highly similar to that of the ΔcheA or ΔcheA-R mutant strains. These findings suggest that through controlling flagella-driven motility behavior, the chemotaxis signaling pathway in A. caulinodans coordinates biofilm formation, EPS, and competitive colonization and nodulation.}, } @article {pmid29424644, year = {2018}, author = {Schultz, GS and Woo, K and Weir, D and Yang, Q}, title = {Effectiveness of a monofilament wound debridement pad at removing biofilm and slough: ex vivo and clinical performance.}, journal = {Journal of wound care}, volume = {27}, number = {2}, pages = {80-90}, doi = {10.12968/jowc.2018.27.2.80}, pmid = {29424644}, issn = {0969-0700}, mesh = {Aged ; Aged, 80 and over ; Animals ; *Bandages ; Biofilms ; Debridement/*instrumentation ; Disease Models, Animal ; Female ; Humans ; Male ; Middle Aged ; Necrosis/surgery ; Pseudomonas Infections/*surgery ; *Pseudomonas aeruginosa ; Skin/pathology ; Surgical Wound Infection/*surgery ; Swine ; }, abstract = {OBJECTIVE: Removal of slough and other devitalised tissue is an important step in biofilm-based wound care (BBWC) and wound bed preparation. Debridement is key to management of both slough and biofilm, and a number of methods are available to achieve this, including surgical/sharp and mechanical debridement. Developments have led to products indicated for debridement of wounds, including a sterile pad consisting of monofilament fibres. Our aim is to examine the effectiveness of a monofilament wound debridement pad (WDP), Debrisoft.

METHOD: We assessed the WDP, in laboratory tests, for the removal of mature biofilm from porcine dermal tissue in an ex vivo model, and the clinical management of sloughy wounds that would benefit from debridement. We used the UPPER score to determine the superficial infection status.

RESULTS: The WDP was effective in removing biofilm from porcine dermal tissue. A case series of 10 patients with chronic wounds suggested that the WDP was beneficial in the removal of slough. All chronic wounds had slough and were cleaned weekly, for four weeks, using the MDP to achieve improved healing and a clean wound bed. The average wound size decreased from 8.09cm[2] at baseline to 2.3cm[2] at week four, with three wounds healed completely. Exudate was reduced, and the UPPER score improved in every patient.

CONCLUSION: These results indicate that the WDP effectively debrides biofilm and slough, and contributes to care that follows the principles of wound bed preparation and BBWC.}, } @article {pmid29424050, year = {2018}, author = {Lamas, A and Regal, P and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM}, title = {Salmonella and Campylobacter biofilm formation: a comparative assessment from farm to fork.}, journal = {Journal of the science of food and agriculture}, volume = {98}, number = {11}, pages = {4014-4032}, doi = {10.1002/jsfa.8945}, pmid = {29424050}, issn = {1097-0010}, mesh = {Animals ; *Biofilms ; Campylobacter/classification/genetics/isolation & purification/*physiology ; Food Contamination/analysis ; Foodborne Diseases/*microbiology ; Humans ; Salmonella/classification/genetics/isolation & purification/*physiology ; }, abstract = {It takes several steps to bring food from the farm to the fork (dining table), and contamination with food-borne pathogens can occur at any point in the process. Campylobacter spp. and Salmonella spp. are the main microorganisms responsible for foodborne disease in the EU. These two pathogens are able to persist throughout the food supply chain thanks to their ability to form biofilms. Owing to the high prevalence of Salmonella and especially of Campylobacter in the food supply chain and the huge efforts of food authorities to reduce these levels, it is of great importance to fully understand their mechanisms of persistence. Diverse studies have evaluated the biofilm-forming capacity of foodborne pathogens isolated at different steps of food production. Nonetheless, the principal obstacle of these studies is to reproduce the real conditions that microorganisms encounter in the food supply chain. While there are a wide number of Salmonella biofilm studies, information on Campylobacter biofilms is still limited. A comparison between the two microorganisms could help to develop new research in the field of Campylobacter biofilms. Therefore, this review evaluates relevant work in the field of Salmonella and Campylobacter biofilms and the applicability of the data obtained from these studies to real working conditions. © 2018 Society of Chemical Industry.}, } @article {pmid29422943, year = {2017}, author = {Verotta, D and Haagensen, J and Spormann, AM and Yang, K}, title = {Mathematical Modeling of Biofilm Structures Using COMSTAT Data.}, journal = {Computational and mathematical methods in medicine}, volume = {2017}, number = {}, pages = {7246286}, pmid = {29422943}, issn = {1748-6718}, support = {R01 AI097380/AI/NIAID NIH HHS/United States ; }, mesh = {Algorithms ; *Biofilms ; Computer Simulation ; Image Processing, Computer-Assisted/*methods ; Kinetics ; Microscopy, Confocal ; Models, Statistical ; Multivariate Analysis ; Pseudomonas aeruginosa/*growth & development ; Software ; }, abstract = {Mathematical modeling holds great potential for quantitatively describing biofilm growth in presence or absence of chemical agents used to limit or promote biofilm growth. In this paper, we describe a general mathematical/statistical framework that allows for the characterization of complex data in terms of few parameters and the capability to (i) compare different experiments and exposures to different agents, (ii) test different hypotheses regarding biofilm growth and interaction with different agents, and (iii) simulate arbitrary administrations of agents. The mathematical framework is divided to submodels characterizing biofilm, including new models characterizing live biofilm growth and dead cell accumulation; the interaction with agents inhibiting or stimulating growth; the kinetics of the agents. The statistical framework can take into account measurement and interexperiment variation. We demonstrate the application of (some of) the models using confocal microscopy data obtained using the computer program COMSTAT.}, } @article {pmid29422525, year = {2018}, author = {Han, B and Zhang, S and Wang, P and Wang, C}, title = {Effects of water flow on submerged macrophyte-biofilm systems in constructed wetlands.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {2650}, pmid = {29422525}, issn = {2045-2322}, mesh = {Alismatales/*growth & development ; Biofilms/*growth & development ; Biomass ; Hydrocharitaceae/*growth & development ; Plant Leaves/growth & development/metabolism ; Water/metabolism ; Wetlands ; }, abstract = {The effects of water flow on the leaf-biofilm interface of Vallisneria natans and Hydrilla verticillata were investigated using artificial plants as the control. Water flow inhibited the growth of two species of submerged macrophytes, reduced oxygen concentrations in plant leaves and changed oxygen profiles at the leaf-biofilm interface. The results from confocal laser scanning microscopy and multifractal analysis showed that water flow reduced biofilm thickness, changed biofilm topographic characterization and increased the percentages of single colony-like biofilm patches. A cluster analysis revealed that the bacterial compositions in biofilms were determined mainly by substrate types and were different from those in sediments. However, water flow increased the bacterial diversity in biofilms in terms of operational taxonomic unit numbers and Shannon Indices. Our results indicated that water flow can be used to regulate the biomass, distribution and bacterial diversities of epiphytic biofilms in constructed wetlands dominated by submerged macrophytes.}, } @article {pmid29422327, year = {2018}, author = {Zajdowicz, S and Song, HB and Baranek, A and Bowman, CN}, title = {Evaluation of biofilm formation on novel copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins for dental restoratives.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {34}, number = {4}, pages = {657-666}, pmid = {29422327}, issn = {1879-0097}, support = {U01 DE023774/DE/NIDCR NIH HHS/United States ; U01 DE023777/DE/NIDCR NIH HHS/United States ; }, mesh = {Alkynes/*chemistry ; Azides/*chemistry ; Biofilms/*growth & development ; Composite Resins/*chemistry ; Copper/*chemistry ; Dental Materials/chemistry ; Materials Testing ; Streptococcus mutans/growth & development ; Surface Properties ; }, abstract = {OBJECTIVE: For the past several decades, the resins used in dental restorations have been plagued with numerous problems, including their implication in biofilm formation and secondary caries. The need for alternative resins is critical, and evaluation of biofilm formation on these resins is essential. The aim of this study was to evaluate in vitro biofilm formation on the surface of novel copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins and composites.

METHODS: CuAAC-based resins/composites made from varying azide monomers and different copper concentrations were compared with BisGMA-TEGDMA resins/composites that served as the control. Biofilms were formed using a mono-species model containing a luciferase-expressing strain of Streptococcus mutans. Luciferase activity was measured and the number of viable bacteria was enumerated on biofilms associated with each resin and composite.

RESULTS: A significant reduction (p<0.05) in luciferase activity, and the number of viable bacteria recovered from biofilms on CuAAC-based resins and composites was observed in comparison to biofilms associated with the BisGMA-TEGDMA controls.

SIGNIFICANCE: CuAAC-based resins do still allow for the formation of biofilms; however, the statistically significant reduction of growth that was associated with the CuAAC resin may enhance the longevity of restorations that incorporate CuAAC-based materials.}, } @article {pmid29421365, year = {2018}, author = {Li, T and Wang, D and Liu, N and Ma, Y and Ding, T and Mei, Y and Li, J}, title = {Inhibition of quorum sensing-controlled virulence factors and biofilm formation in Pseudomonas fluorescens by cinnamaldehyde.}, journal = {International journal of food microbiology}, volume = {269}, number = {}, pages = {98-106}, doi = {10.1016/j.ijfoodmicro.2018.01.023}, pmid = {29421365}, issn = {1879-3460}, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Acyl-Butyrolactones/metabolism ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Molecular Docking Simulation ; Pseudomonas fluorescens/drug effects/metabolism/*pathogenicity ; Quorum Sensing/*drug effects ; Repressor Proteins/*antagonists & inhibitors ; Trans-Activators/*antagonists & inhibitors ; Virulence Factors/antagonists & inhibitors ; }, abstract = {Pseudomonas fluorescens, an important food spoiling bacteria, uses quorum sensing to control biofilm formation and motility. To date, only a few compounds targeting the LuxR-based quorum sensing system of P. fluorescens have been identified. In the present study, the quorum sensing inhibitory effect of cinnamaldehyde at sublethal concentrations was investigated in terms of inhibition of the extracellular protease, biofilm formation, and swimming and swarming motility. The total volatile basic nitrogen value was also measured to evaluate the effect of cinnamaldehyde on quality preservation of turbot fillets stored at 4 ± 1 °C for 15 days. The results showed that cinnamaldehyde significantly inhibited quorum sensing-dependent factors in P. fluorescens and extended the storage life of turbot. Unexpectedly, cinnamaldehyde did not interfere with production of AHLs (N-acylhomoserine lactones) by P. fluorescens, as shown by measurement of AHL production using GC-MS. Molecular docking analysis revealed that cinnamaldehyde can interact with the LuxR-type protein of P. fluorescens, which could constitute the molecular basis of the quorum sensing inhibition observed. These findings strongly suggest that cinnamaldehyde is a quorum sensing inhibitor with great potential for the preservation of aquatic products to guarantee food safety.}, } @article {pmid29421318, year = {2018}, author = {Asadpour, L}, title = {Antimicrobial resistance, biofilm-forming ability and virulence potential of Pseudomonas aeruginosa isolated from burn patients in northern Iran.}, journal = {Journal of global antimicrobial resistance}, volume = {13}, number = {}, pages = {214-220}, doi = {10.1016/j.jgar.2018.01.018}, pmid = {29421318}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Burns/*microbiology ; *Drug Resistance, Multiple, Bacterial ; Humans ; Iran/epidemiology ; Microbial Sensitivity Tests ; Mutation ; Polymerase Chain Reaction ; Pseudomonas Infections/*epidemiology ; Pseudomonas aeruginosa/*drug effects/genetics/*pathogenicity ; Virulence ; Virulence Factors/genetics ; beta-Lactamases/biosynthesis ; }, abstract = {OBJECTIVES: Pseudomonas aeruginosa is a frequent cause of infectious diseases, such as burn and wound infections, making it one of the most menacing opportunistic pathogens. The aim of this study was to investigate the antimicrobial resistance, biofilm-forming ability, and frequency of genes involved in biofilm formation and virulence of P. aeruginosa isolated from burn infections in Iran.

METHODS: Resistance of 90 P. aeruginosa isolates to 12 antimicrobial agents as well as production of extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) enzymes were assessed phenotypically according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Biofilm-forming capacity was assayed in a microtitre plate. The frequency of biofilm- and virulence-associated genes was investigated by PCR. Mutations in gyrA and parC in ciprofloxacin-resistant isolates were also determined by PCR.

RESULTS: In phenotypic assays, 72.2% (65/90) of P. aeruginosa isolates were multidrug-resistant (MDR), 55.5% (50/90) and 35.6% (32/90) were positive for ESBL and MBL production, respectively, and 67.8% (61/90) were positive for biofilm formation. Biofilm- and virulence-associated genes were identified in >50% of the P. aeruginosa isolates, with toxA and lasB being the most frequent. All of the virulence genes were more common in biofilm-forming and MDR phenotypes. Two point mutations in gyrA and one in parC in high-level ciprofloxacin-resistant isolates were identified.

CONCLUSIONS: The results of this study indicate that there is a high frequency of multidrug resistance and a high percentage of virulence-associated genes present in clinical P. aeruginosa isolates in Iran.}, } @article {pmid29420778, year = {2018}, author = {Kadry, AA and El-Ganiny, AM and Mosbah, RA and Kaminskyj, SGW}, title = {Deletion of Aspergillus nidulans GDP-mannose transporters affects hyphal morphometry, cell wall architecture, spore surface character, cell adhesion, and biofilm formation.}, journal = {Medical mycology}, volume = {56}, number = {5}, pages = {621-630}, doi = {10.1093/mmy/myx082}, pmid = {29420778}, issn = {1460-2709}, mesh = {Antifungal Agents/pharmacology ; Aspergillus nidulans/*genetics/*growth & development/ultrastructure ; Biofilms/growth & development ; Carrier Proteins/*genetics ; Cell Adhesion/physiology ; Cell Wall/ultrastructure ; Echinocandins/pharmacology ; Fungal Proteins/*genetics ; Guanosine Diphosphate Mannose/metabolism ; Hyphae/growth & development ; Lipopeptides/pharmacology ; Micafungin ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Morphogenesis ; Sequence Deletion ; Spores, Fungal/growth & development/ultrastructure ; }, abstract = {Systemic human fungal infections are increasingly common. Aspergillus species cause most of the airborne fungal infections. Life-threatening invasive aspergillosis was formerly found only in immune-suppressed patients, but recently some strains of A. fumigatus have become primary pathogens. Many fungal cell wall components are absent from mammalian systems, so they are potential drug targets. Cell-wall-targeting drugs such as echinocandins are used clinically, although echinocandin-resistant strains were discovered shortly after their introduction. Currently there are no fully effective anti-fungal drugs. Fungal cell wall glycoconjugates modulate human immune responses, as well as fungal cell adhesion, biofilm formation, and drug resistance. Guanosine diphosphate (GDP) mannose transporters (GMTs) transfer GDP-mannose from the cytosol to the Golgi lumen prior to mannosylation. Aspergillus nidulans GMTs are encoded by gmtA and gmtB. Here we elucidate the roles of A. nidulans GMTs. Strains engineered to lack either or both GMTs were assessed for hyphal and colonial morphology, cell wall ultrastructure, antifungal susceptibility, spore hydrophobicity, adherence and biofilm formation. The gmt-deleted strains had smaller colonies with reduced sporulation and with thicker hyphal walls. The gmtA deficient spores had reduced hydrophobicity and were less adherent and less able to form biofilms in vitro. Thus, gmtA not only participates in maintaining the cell wall integrity but also plays an important role in biofilm establishment and adherence of A. nidulans. These findings suggested that GMTs have roles in A. nidulans growth and cell-cell interaction and could be a potential target for new antifungals that target virulence determinants.}, } @article {pmid29420616, year = {2018}, author = {Ahn, KB and Baik, JE and Park, OJ and Yun, CH and Han, SH}, title = {Lactobacillus plantarum lipoteichoic acid inhibits biofilm formation of Streptococcus mutans.}, journal = {PloS one}, volume = {13}, number = {2}, pages = {e0192694}, pmid = {29420616}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Humans ; Lactobacillus plantarum/*metabolism ; Lipopolysaccharides/*physiology ; Streptococcus mutans/*growth & development ; Teichoic Acids ; }, abstract = {Dental caries is a biofilm-dependent oral disease and Streptococcus mutans is the known primary etiologic agent of dental caries that initiates biofilm formation on tooth surfaces. Although some Lactobacillus strains inhibit biofilm formation of oral pathogenic bacteria, the molecular mechanisms by which lactobacilli inhibit bacterial biofilm formation are not clearly understood. In this study, we demonstrated that Lactobacillus plantarum lipoteichoic acid (Lp.LTA) inhibited the biofilm formation of S. mutans on polystyrene plates, hydroxyapatite discs, and dentin slices without affecting the bacterial growth. Lp.LTA interferes with sucrose decomposition of S. mutans required for the production of exopolysaccharide, which is a main component of biofilm. Lp.LTA also attenuated the biding of fluorescein isothiocyanate-conjugated dextran to S. mutans, which is known to have a high affinity to exopolysaccharide on S. mutans. Dealanylated Lp.LTA did not inhibit biofilm formation of S. mutans implying that D-alanine moieties in the Lp.LTA structure were crucial for inhibition. Collectively, these results suggest that Lp.LTA attenuates S. mutans biofilm formation and could be used to develop effective anticaries agents.}, } @article {pmid29417313, year = {2018}, author = {Loo, CY and Lee, WH and Lauretani, G and Scalia, S and Cipolla, D and Traini, D and Young, P and Ong, HX}, title = {Sweetening Inhaled Antibiotic Treatment for Eradication of Chronic Respiratory Biofilm Infection.}, journal = {Pharmaceutical research}, volume = {35}, number = {3}, pages = {50}, pmid = {29417313}, issn = {1573-904X}, support = {ARC-LP160100427//Australian Research Council/ ; }, mesh = {Administration, Inhalation ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Cell Line, Tumor ; Chronic Disease/drug therapy ; Ciprofloxacin/*pharmacology/therapeutic use ; Drug Combinations ; Drug Resistance, Bacterial/drug effects ; Humans ; Mannitol/*pharmacology/therapeutic use ; Nebulizers and Vaporizers ; Permeability ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; Respiratory Tract Infections/*drug therapy/microbiology ; }, abstract = {PURPOSE: The failure of chronic therapy with antibiotics to clear persistent respiratory infection is the key morbidity and mortality factor for patients with chronic lung diseases, primarily due to the presence of biofilm in the lungs. It is hypothesised that carbon sources, such as mannitol, could stimulate the metabolic activity of persister cells within biofilms and restore their susceptibility to antibiotics. The aims of the current study are to: (1) establish a representative in vitro model of Pseudomonas aeruginosa biofilm lung infection, and (2) investigate the effects of nebulised mannitol on antibiotic efficacy, focusing on ciprofloxacin, in the eradication of biofilm.

METHOD: Air interface biofilm was cultured onto Snapwell inserts incorporated into a modified pharmacopeia deposition apparatus, the Anderson Cascade Impactor (ACI). Three different formulations including mannitol only, ciprofloxacin only and combined ciprofloxacin and mannitol were nebulised onto the P. aeruginosa biofilm using the modified ACI. Antibacterial effectiveness was evaluated using colony-forming units counts, biofilm penetration and scanning electron microscopy.

RESULTS: Nebulised mannitol promotes the dispersion of bacteria from the biofilm and demonstrated a synergistic enhancement of the antibacterial efficacy of ciprofloxacin compared to delivery of antibiotic alone.

CONCLUSIONS: The combination of ciprofloxacin and mannitol may provide an important new strategy to improve antibiotic therapy for the treatment of chronic lung infections. Furthermore, the development of a representative lung model of bacterial biofilm could potentially be used as a platform for future new antimicrobial pre-clinical screening.}, } @article {pmid29416528, year = {2018}, author = {Lee, Y and Song, S and Sheng, L and Zhu, L and Kim, JS and Wood, TK}, title = {Substrate Binding Protein DppA1 of ABC Transporter DppBCDF Increases Biofilm Formation in Pseudomonas aeruginosa by Inhibiting Pf5 Prophage Lysis.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {30}, pmid = {29416528}, issn = {1664-302X}, abstract = {Filamentous phage impact biofilm development, stress tolerance, virulence, biofilm dispersal, and colony variants. Previously, we identified 137 Pseudomonas aeruginosa PA14 mutants with more than threefold enhanced and 88 mutants with more than 10-fold reduced biofilm formation by screening 5850 transposon mutants (PLoS Pathogens5: e1000483, 2009). Here, we characterized the function of one of these 225 mutations, dppA1 (PA14_58350), in regard to biofilm formation. DppA1 is a substrate-binding protein (SBP) involved in peptide utilization via the DppBCDF ABC transporter system. We show that compared to the wild-type strain, inactivating dppA1 led to 68-fold less biofilm formation in a static model and abolished biofilm formation in flow cells. Moreover, the dppA1 mutant had a delay in swarming and produced 20-fold less small-colony variants, and both biofilm formation and swarming were complemented by producing DppA1. A whole-transcriptome analysis showed that only 10 bacteriophage Pf5 genes were significantly induced in the biofilm cells of the dppA1 mutant compared to the wild-type strain, and inactivation of dppA1 resulted in a 600-fold increase in Pf5 excision and a million-fold increase in phage production. As expected, inactivating Pf5 genes PA0720 and PA0723 increased biofilm formation substantially. Inactivation of DppA1 also reduced growth (due to cell lysis). Hence, DppA1 increases biofilm formation by repressing Pf5 prophage.}, } @article {pmid29414837, year = {2018}, author = {Ren, W and Cai, R and Yan, W and Lyu, M and Fang, Y and Wang, S}, title = {Purification and Characterization of a Biofilm-Degradable Dextranase from a Marine Bacterium.}, journal = {Marine drugs}, volume = {16}, number = {2}, pages = {}, pmid = {29414837}, issn = {1660-3397}, mesh = {Biofilms/*drug effects ; Dental Caries/drug therapy ; Dextranase/biosynthesis/isolation & purification/*pharmacology ; Hydrogen-Ion Concentration ; Metals/metabolism/pharmacology ; Proteobacteria/*chemistry ; Seawater/*microbiology ; Streptococcus mutans/drug effects ; Substrate Specificity ; Temperature ; Tooth/microbiology ; }, abstract = {This study evaluated the ability of a dextranase from a marine bacterium Catenovulum sp. (Cadex) to impede formation of Streptococcus mutans biofilms, a primary pathogen of dental caries, one of the most common human infectious diseases. Cadex was purified 29.6-fold and had a specific activity of 2309 U/mg protein and molecular weight of 75 kDa. Cadex showed maximum activity at pH 8.0 and 40 °C and was stable at temperatures under 30 °C and at pH ranging from 5.0 to 11.0. A metal ion and chemical dependency study showed that Mn[2+] and Sr[2+] exerted positive effects on Cadex, whereas Cu[2+], Fe[3+], Zn[2+], Cd[2+], Ni[2+], and Co[2+] functioned as inhibitors. Several teeth rinsing product reagents, including carboxybenzene, ethanol, sodium fluoride, and xylitol were found to have no effects on Cadex activity. A substrate specificity study showed that Cadex specifically cleaved the α-1,6 glycosidic bond. Thin layer chromatogram and high-performance liquid chromatography indicated that the main hydrolysis products were isomaltoogligosaccharides. Crystal violet staining and scanning electron microscopy showed that Cadex impeded the formation of S. mutans biofilm to some extent. In conclusion, Cadex from a marine bacterium was shown to be an alkaline and cold-adapted endo-type dextranase suitable for development of a novel marine agent for the treatment of dental caries.}, } @article {pmid29413933, year = {2018}, author = {Wang, L and Li, Y and Wang, L and Zhu, M and Zhu, X and Qian, C and Li, W}, title = {Responses of biofilm microorganisms from moving bed biofilm reactor to antibiotics exposure: Protective role of extracellular polymeric substances.}, journal = {Bioresource technology}, volume = {254}, number = {}, pages = {268-277}, doi = {10.1016/j.biortech.2018.01.063}, pmid = {29413933}, issn = {1873-2976}, mesh = {*Anti-Bacterial Agents ; Bacteria ; *Biofilms ; *Polymers ; Tetracycline ; }, abstract = {EPS can affect the migration of antibiotics in biofilm reactors, however the roles of biofilm EPS on the fate of antibiotics and the protective mechanisms to bacterial community remain unknown. We investigated the transport of three representative antibiotics in the biofilm suspension from a moving bed biofilm reactor. Spectral analysis suggested that proteins dominated the interactions between EPS and antibiotics. The adsorbed amounts of antibiotics onto EPS accounted for 14.5%, 88.2% and 13.1% of total concentration for sulfamethizole, tetracycline and norfloxacin, respectively at the biodegradation stage. The respiratory rates and representative enzymatic activities all experienced declines for biofilm without EPS in exposure to antibiotics. Gene sequencing results indicated that the bacterial community in biofilm without EPS was more vulnerable to antibiotics shocks. Our results demonstrated the protective roles of biofilm EPS in resisting antibiotics stresses, which provides important implications for understanding the bioremediation of antibiotics in biofilm systems.}, } @article {pmid29413589, year = {2018}, author = {Omwenga, EO and Hensel, A and Shitandi, A and Goycoolea, FM}, title = {Chitosan nanoencapsulation of flavonoids enhances their quorum sensing and biofilm formation inhibitory activities against an E.coli Top 10 biosensor.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {164}, number = {}, pages = {125-133}, doi = {10.1016/j.colsurfb.2018.01.019}, pmid = {29413589}, issn = {1873-4367}, mesh = {Animals ; Biofilms/*drug effects ; *Biosensing Techniques ; Cell Death/drug effects ; Chitosan/*chemistry ; Dogs ; Drug Liberation ; Escherichia coli/*drug effects/*physiology ; Flavanones/pharmacology ; Flavonoids/*pharmacology ; Madin Darby Canine Kidney Cells ; Nanocapsules/*chemistry ; Particle Size ; Pseudomonas aeruginosa/drug effects ; Quercetin/pharmacology ; Quorum Sensing/*drug effects ; }, abstract = {Phytochemicals have been found to be promising alternatives to conventional antibiotic therapies for the control of bacterial infections, as they may entail less selective pressure and hence reduce the development of resistance. This study involved examining the inhibition of biofilm formation and of quorum sensing (QS), and the cytotoxicity on mammalian cells of two flavonoids, quercetin and baicalein, in free form and associated into chitosan-based nanocapsules. This was done by use of a transformed E. coli Top 10 biosensor strain, while the cytotoxicity was evaluated on MDCK-C7 cells. In free form, application both flavonoids exhibited slight inhibitory activity on the QS response and biofilm formation, a scenario that was improved positively upon encapsulation with chitosan (Mw ∼115,000 g/mol and DA ∼42%). The association efficiency of 99% (quercetin) and 87% (baicalein) was determined, and each formulation had an average diameter of 190 ± 4 and 187 ± 2 nm, and zeta (ζ) potential of +48.1 ± 2.03 and +48.4 ± 3.46 mV, respectively. Both types of systems were stable against aggregation in M9 and MEM media. The in vitro release kinetics data of both flavonoids seemed to be similar with only ∼20% released over the first 5 h, or ∼10% over the first 4 h, respectively, with subsequent sudden release increase up to ∼40% in both cases. The free phytochemicals seemed to be cytotoxic to MDCK-C7 cells at higher doses, however, upon nanoencapsulation, a cytoprotective effect was evidenced. We have gained proof-of-principle of the advantages of encapsulation of two bioactive flavonoids.}, } @article {pmid29412515, year = {2018}, author = {Cho, DY and Lim, DJ and Mackey, C and Weeks, CG and Peña Garcia, JA and Skinner, D and Grayson, JW and Hill, HS and Alexander, DK and Zhang, S and Woodworth, BA}, title = {l-Methionine anti-biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor.}, journal = {International forum of allergy & rhinology}, volume = {8}, number = {5}, pages = {577-583}, pmid = {29412515}, issn = {2042-6984}, support = {P30 DK072482/DK/NIDDK NIH HHS/United States ; R01 HL133006/HL/NHLBI NIH HHS/United States ; }, mesh = {Aminophenols/*therapeutic use ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Chronic Disease ; Cystic Fibrosis Transmembrane Conductance Regulator/antagonists & inhibitors ; Disease Progression ; Drug Resistance ; Drug Synergism ; Drug Therapy, Combination ; Humans ; Methionine/pharmacology/*therapeutic use ; Pseudomonas Infections/complications/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Quinolones/*therapeutic use ; Rhinitis/complications/drug therapy ; Sinusitis/complications/drug therapy ; }, abstract = {BACKGROUND: Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l-Methionine is an amino acid with reported biofilm-inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co-treatment with ivacaftor and l-methionine can reduce the formation of Pseudomonas aeruginosa biofilms.

METHODS: P aeruginosa (PAO-1 strain) biofilms were studied in the presence of l-methionine and/or ivacaftor. For static biofilm assays, PAO-1 was cultured in a 48-well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter-Glo™ assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs.

RESULTS: l-Methionine (0.5 μM) significantly reduced PAO-1 biofilm mass (32.4 ± 18.0%; n = 4; p < 0.001) compared with controls. Low doses of ivacaftor alone (4, 8, and 12 μg/mL) had no effect on biofilm formation. When combined with ivacaftor (4 μg/mL), a synergistic anti-biofilm effect was noted at 0.05 μM and 0.5 μM of l-methionine (two-way analysis of variane, p = 0.0415) compared with corresponding concentrations of l-methionine alone.

CONCLUSION: Ivacaftor enhanced the anti-biofilm activity of l-methionine against the PAO-1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l-methionine combinations for P aeruginosa sinusitis are planned.}, } @article {pmid29411720, year = {2018}, author = {Gökmenoglu, C and Kara, NB and Beldüz, M and Kamburoğlu, A and Tosun, I and Sadik, E and Kara, C}, title = {Evaluation of Candida Albicans biofilm formation on various parts of implant material surfaces.}, journal = {Nigerian journal of clinical practice}, volume = {21}, number = {1}, pages = {33-37}, doi = {10.4103/1119-3077.224793}, pmid = {29411720}, issn = {1119-3077}, mesh = {Anilides ; Biofilms/*growth & development ; Candida albicans/*physiology ; Colorimetry ; Dental Abutments/*microbiology ; Dental Implants/*microbiology ; *Dental Materials ; Microscopy, Electron, Scanning ; Tetrazolium Salts ; }, abstract = {AIMS: Candida albicans adhesion to any oral substrata is the first and essential stage in forming a pathogenic fungal biofilm. In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, non-biological surfaces, such as dental materials. C. albicans adhesion to denture materials is widely recognized as the main reason for the development of stomatitis. This study compared the susceptibility of different parts of the implant system with C. albicans adhesion.

MATERIAL AND METHODS: Each material maintained contact with C. albicans suspension, and biofilm formations around the implant materials were evaluated. To evaluate the biofilm formation, the XTT technique and scanning electron microscopy (SEM) were used.

RESULTS: In general, a fine biofilm layer of C. albicans species was found on the surface of all examined materials. However, when examining the SEM images, candidal growth was significantly lower on the surfaces of the gingival former, abutment, and machined surface implant samples. According to the colorimetric assay (XTT), the gingival former samples revealed the lowest quantity of biofilms formed (median XTT value, 0.0891) (P < 0.001). The abutment and machined surface implant samples had low XTT values with similar values. The highest median colorimetric XTT values (0.1741), significantly higher than those of the other materials (P < 0.001), were for the bone level implant samples.

CONCLUSIONS: This finding emphasizes implant treatment would be chosen complacency in patients who are prone to oral candidosis, medically compromised patients under immunosuppression, and patients with tumor who are being treated with chemotherapy or radiation.}, } @article {pmid29410771, year = {2018}, author = {Muras, A and Mayer, C and Romero, M and Camino, T and Ferrer, MD and Mira, A and Otero, A}, title = {Inhibition of Steptococcus mutans biofilm formation by extracts of Tenacibaculum sp. 20J, a bacterium with wide-spectrum quorum quenching activity.}, journal = {Journal of oral microbiology}, volume = {10}, number = {1}, pages = {1429788}, pmid = {29410771}, issn = {2000-2297}, abstract = {Background: Previous studies have suggested the quorum sensing signal AI-2 as a potential target to prevent the biofilm formation by Streptococcus mutans, a pathogen involved in tooth decay. Objective: To obtain inhibition of biofilm formation by S. mutans by extracts obtained from the marine bacterium Tenacibaculum sp. 20J interfering with the AI-2 quorum sensing system. Design: The AI-2 inhibitory activity was tested with the biosensors Vibrio harveyi BB170 and JMH597. S. mutans ATCC25175 biofilm formation was monitored using impedance real-time measurements with the xCELLigence system®, confocal laser microscopy, and the crystal violet quantification method. Results: The addition of the cell extract from Tenacibaculum sp. 20J reduced biofilm formation in S. mutans ATCC25175 by 40-50% compared to the control without significantly affecting growth. A decrease of almost 40% was also observed in S. oralis DSM20627 and S. dentisani 7747 biofilms. Conclusions: The ability of Tenacibaculum sp. 20J to interfere with AI-2 and inhibit biofilm formation in S. mutans was demonstrated. The results indicate that the inhibition of quorum sensing processes may constitute a suitable strategy for inhibiting dental plaque formation, although additional experiments using mixed biofilm models would be required.}, } @article {pmid29410654, year = {2018}, author = {Levipan, HA and Quezada, J and Avendaño-Herrera, R}, title = {Stress Tolerance-Related Genetic Traits of Fish Pathogen Flavobacterium psychrophilum in a Mature Biofilm.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {18}, pmid = {29410654}, issn = {1664-302X}, abstract = {Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout fry syndrome, and hence this bacterium is placed among the most important salmonid pathogens in the freshwater aquaculture industry. Since bacteria in biofilms differ substantially from free-living counterparts, this study sought to find the main differences in gene expression between sessile and planktonic states of F. psychrophilum LM-02-Fp and NCMB1947[T], with focus on stress-related changes in gene expression occurring during biofilm formation. To this end, biofilm and planktonic samples were analyzed by RNA sequencing to detect differentially expressed candidate genes (DECGs) between the two growth states, and decreasing the effects of interstrain variation by considering only genes with log2-fold changes ≤ -2 and ≥ 2 at Padj-values ≤ 0.001 as DECGs. Overall, 349 genes accounting for ~15% of total number of genes expressed in transcriptomes of F. psychrophilum LM-02-Fp and NCMB1947[T] (n = 2327) were DECGs between biofilm and planktonic states. Approximately 83 and 81% of all up- and down-regulated candidate genes in mature biofilms, respectively, were assigned to at least one gene ontology term; these were primarily associated with the molecular function term "catalytic activity." We detected a potential stress response in mature biofilms, characterized by a generalized down-regulation of DECGs with roles in the protein synthesis machinery (n = 63, primarily ribosomal proteins) and energy conservation (seven ATP synthase subunit genes), as well as an up-regulation of DECGs involved in DNA repair (ruvC, recO, phrB1, smf, and dnaQ) and oxidative stress response (cytochrome C peroxidase, probable peroxiredoxin, and a probable thioredoxin). These results support the idea of a strategic trade-off between growth-related processes and cell homeostasis to preserve biofilm structure and metabolic functioning. In addition, LDH-based cytotoxicity assays and an intraperitoneal challenge model for rainbow trout fry agreed with the transcriptomic evidence that the ability of F. psychrophilum to form biofilms could contribute to the virulence. Finally, the reported changes in gene expression, as induced by the plankton-to-biofilm transition, represent the first transcriptomic guideline to obtain insights into the F. psychrophilum biofilm lifestyle that could help understand the prevalence of this bacterium in aquaculture settings.}, } @article {pmid29410321, year = {2018}, author = {Harper, RA and Saleh, MM and Carpenter, G and Abbate, V and Proctor, G and Harvey, RD and Gambogi, RJ and Geonnotti, A and Hider, R and Jones, SA}, title = {Soft, adhesive (+) alpha tocopherol phosphate planar bilayers that control oral biofilm growth through a substantive antimicrobial effect.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {14}, number = {7}, pages = {2307-2316}, doi = {10.1016/j.nano.2017.12.024}, pmid = {29410321}, issn = {1549-9642}, mesh = {Adhesives ; Anti-Infective Agents/*administration & dosage/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Humans ; Lipid Bilayers/*chemistry ; Liposomes/administration & dosage/chemistry ; Microscopy, Atomic Force ; Mouth/microbiology ; Saliva/*microbiology ; Streptococcus mutans/*drug effects/growth & development ; Streptococcus oralis/*drug effects/growth & development ; alpha-Tocopherol/*analogs & derivatives/chemistry/pharmacology ; }, abstract = {'Soft' nanomaterials have the potential to produce substantive antibiofilm effects. The aim of this study was to understand the oral antimicrobial activity of soft nanomaterials generated from alpha-tocopherol (α-T) and alpha-tocopherol phosphate (α-TP). (+) α-TP formed planar bilayer islands (175 ± 21 nm, -14.9 ± 3.5 mV) in a Trizma® buffer, whereas (+) α-T formed spherical liposomes (563 ± 1 nm, -10.5 ± 0.2 mV). The (+) α-TP bilayers displayed superior Streptococcus oralis biofilm growth retardation, a more substantive action, generated a superior adsorption to hydroxyapatite and showed an enhanced inhibition of multi-species bacterial saliva biofilm growth (38 ± 7μm vs 58 ± 18 μm, P ˂ 0.05) compared to (+) α-T. Atomic force microscopy data indicated that the ability of the 'soft' α-TP nanomaterials to transition into planar bilayer structures upon contact with interfaces facilitated their adhesive properties and substantive antimicrobial effects.}, } @article {pmid29409364, year = {2018}, author = {Dubey, N and Ellepola, K and Decroix, FED and Morin, JLP and Castro Neto, AH and Seneviratne, CJ and Rosa, V}, title = {Graphene onto medical grade titanium: an atom-thick multimodal coating that promotes osteoblast maturation and inhibits biofilm formation from distinct species.}, journal = {Nanotoxicology}, volume = {12}, number = {4}, pages = {274-289}, doi = {10.1080/17435390.2018.1434911}, pmid = {29409364}, issn = {1743-5404}, mesh = {Biofilms/*drug effects ; Cell Differentiation/*drug effects ; Cell Proliferation/drug effects ; Cells, Cultured ; Coated Materials, Biocompatible/chemistry/*pharmacology ; Graphite/chemistry/*pharmacology ; Humans ; Osteoblasts/*cytology/*drug effects ; Surface Properties ; Titanium/chemistry/*pharmacology ; }, abstract = {The time needed for the osseointegration of titanium implants is deemed too long. Moreover, the bacterial colonization of their surfaces is a major cause of failure. Graphene can overcome these issues but its wet transfer onto substrates employs hazardous chemicals limiting the clinical applications. Alternatively, dry transfer technique has been developed, but the biological properties of this technique remain unexplored. Here, a dry transfer technique based on a hot-pressing method allowed to coat titanium substrates with high-quality graphene and coverage area >90% with a single transfer. The graphene-coated titanium is cytocompatible, did not induce cell membrane damage, induced human osteoblast maturation (gene and protein level), and increased the deposition of mineralized matrix compared to titanium alone. Moreover, graphene decreased the formation of biofilms from Streptococcus mutans, Enterococcus faecalis and even from whole saliva on titanium without killing the bacteria. These findings confirm that coating of titanium with graphene via a dry transfer technique is a promising strategy to improve osseointegration and prevent biofilm formation on implants and devices.}, } @article {pmid29408987, year = {2018}, author = {Tang, D and Gao, Q and Zhao, Y and Li, Y and Chen, P and Zhou, J and Xu, R and Wu, Z and Xu, Y and Li, H}, title = {Mg2+ reduces biofilm quantity in Acidithiobacillus ferrooxidans through inhibiting Type IV pili formation.}, journal = {FEMS microbiology letters}, volume = {365}, number = {4}, pages = {}, doi = {10.1093/femsle/fnx266}, pmid = {29408987}, issn = {1574-6968}, mesh = {Acidithiobacillus/*drug effects/genetics/*physiology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Fimbriae, Bacterial/drug effects/genetics/*metabolism ; Magnesium/*pharmacology ; }, abstract = {Bioleaching is a promising process for 350 million tons of Jinchuan low-grade pentlandite. But high concentration of Mg2+ is harmful to bioleaching microorganisms. Interestingly, biofilm formation can improve leaching rate. Thus, it is actually necessary to investigate the effect of Mg2+ stress on Acidithiobacillus ferrooxidans biofilms formation. In this study, we found that 0.1 and 0.5 M Mg2+ stress significantly reduced the total biomass of biofilm in a dose-dependent manner. The observation results of extracellular polymeric substances and bacteria using confocal laser scanning microscopy showed that the biofilm became thinner and looser under Mg2+ stress. Whereas 0.1 and 0.5 M Mg2+ stress had no remarkable effect on the bacterial viability, the attachment rate of Acidithiobacillus ferrooxidans to pentlandite was reduced by Mg2+ stress. Furthermore, sliding motility, twitching motility and the gene expression level of pilV and pilW were inhibited under Mg2+ stress. These results suggested that Mg2+ reduced biofilm formation through inhibiting pilV and pilW gene expression, decreasing Type IV pili formation and then attenuating the ability of attachment, subduing the active expansion of biofilms mediated by twitching motility. This study provided more information about the effect of Mg2+ stress on biofilm formation and may be useful for increasing the leaching rate in low-grade pentlandit.}, } @article {pmid29408611, year = {2018}, author = {Muñoz, P and Agnelli, C and Guinea, J and Vena, A and Álvarez-Uría, A and Marcos-Zambrano, LJ and Escribano, P and Valerio, M and Bouza, E}, title = {Is biofilm production a prognostic marker in adults with candidaemia?.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {24}, number = {9}, pages = {1010-1015}, doi = {10.1016/j.cmi.2018.01.022}, pmid = {29408611}, issn = {1469-0691}, mesh = {Adult ; Aged ; *Biofilms ; Biomass ; Candida/*growth & development/isolation & purification ; Candidemia/*microbiology/*mortality ; Critical Care ; Female ; Humans ; Middle Aged ; Prognosis ; Retrospective Studies ; Risk Factors ; }, abstract = {OBJECTIVES: The role of biofilm production in the outcome of candidaemia remains under discussion. Current evidence relies on variable biofilm detection methods while evaluating distinct clinical end points. We aimed to determine the impact of biofilm production measured by metabolic activity (MA) and biomass (BM) on the prognosis of adults with candidaemia.

METHODS: Retrospective cohort including 280 adults with candidaemia admitted from 2010 to 2016. BM was assessed using crystal violet binding stain and the XTT reduction assay was used to detect MA. Strains were classified as high and moderate-low biofilm producers according to published cut-offs. The primary outcome was overall mortality within 7 and 30 days. The secondary outcome was unfavourable prognosis defined as metastatic infection, admission to an intensive care unit due to the severity of candidaemia, or death within 30 days.

RESULTS: High BM and high MA were detected in 90 (32.1%) and 114 (40.7%) of the 280 isolates, respectively. Comparison of high and moderate-low biofilm forming isolates revealed no correlation between biofilm production and 7-day mortality (BM high 15/90 (16.7%) versus moderate-low 24/190 (12.6%); MA high 12/114 (10.5%) versus moderate-low 27/166 (16.3%)), 30-day mortality (BM high 34/90 (37.8%) versus moderate-low 61/190 (32.1%); MA high 33/114 (28.9%) versus moderate-low 62/166 (37.3%)), or unfavourable prognosis (BM high 45/90 (50.0%) versus moderate-low 73/190 (38.4%); MA high 41/114 (36.0%) versus moderate-low 77/166 (46.4%)).

CONCLUSIONS: Biofilm production was not a predictor of mortality or of unfavourable prognosis in adults with candidaemia.}, } @article {pmid29408292, year = {2018}, author = {Fumes, AC and da Silva Telles, PD and Corona, SAM and Borsatto, MC}, title = {Effect of aPDT on Streptococcus mutans and Candida albicans present in the dental biofilm: Systematic review.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {363-366}, doi = {10.1016/j.pdpdt.2018.01.013}, pmid = {29408292}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects ; Dentistry ; Humans ; Methylene Blue/*pharmacology ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Streptococcus mutans/*drug effects ; Time Factors ; }, abstract = {To evaluate the effect of aPDT on S. mutans and C. albicans present in the dental biofilm, using methylene blue as a photosensitizer in different pre-irradiation times. The searches were made on Pubmed, Web of Science, Bireme, Scopus and Cochrane Library, and were complemented by screening the references of selected articles in the attempt to find any article that did not appear in the database search. The searches were performed by two researchers and limited to studies involving human subjects published in the English language. Inclusion criteria included in vitro studies with aPDT; studies that used methylene blue as a photosensitizer; studies that used low power laser; studies that evaluated S. mutans or C. albicans. Studies published in a non-English language, patents, in vivo or in situ studies; case reports, serial case, reviews and animal studies were not included. Studies published before 1996 were also not included. Initially, the search resulted in 68 published studies. 16 records were excluded because they were duplicated. The analysis of titles and abstracts resulted in the exclusion of 48 of the published studies, resulting in 4 studies included in the systematic review. The aPDT was effective in three of the four papers selected for the systematic review and the pre-irradiation time used was 5 or 15 min. This therapy had satisfactory results in both C. albicans and S. mutans when using methylene blue as a photosensitizer.}, } @article {pmid29407750, year = {2018}, author = {Yoo, HJ and Jwa, SK}, title = {Inhibitory effects of β-caryophyllene on Streptococcus mutans biofilm.}, journal = {Archives of oral biology}, volume = {88}, number = {}, pages = {42-46}, doi = {10.1016/j.archoralbio.2018.01.009}, pmid = {29407750}, issn = {1879-1506}, mesh = {Anti-Infective Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; DNA, Bacterial/analysis ; Dental Caries/microbiology/prevention & control ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/drug effects/genetics ; Glucosyltransferases/genetics/metabolism ; Microbial Sensitivity Tests ; Polycyclic Sesquiterpenes ; Sesquiterpenes/*antagonists & inhibitors ; Streptococcus mutans/*drug effects/growth & development ; }, abstract = {OBJECTIVE: The biofilm of Streptococcus mutans is associated with induction of dental caries. Also, they produce glucan as an extracellular polysaccharide through glucosyltransferases and help the formation of cariogenic biofilm. β-caryophyllene has been used for therapeutic agent in traditional medicine and has antimicrobial activity. The purpose of this study was to investigate the effect of β-caryophyllene on S. mutans biofilm and the expression of biofilm-related factor.

DESIGN: The susceptibility assay of S. mutans for β-caryophyllene was performed to investigate inhibitory concentration for S. mutans growth. To evaluated the effect of β-caryophyllene on S. mutans biofilm, β-caryophyllene was treated on S. mutans in the various concentrations before or after the biofilm formation. Live S. mutans in the biofilm was counted by inoculating on Mitis-salivarius agar plate, and S. mutans biofilm was analyzed by confocal laser scanning microscope after staining bacterial live/dead staining kit. Finally, the expression of glucosyltransferases of S. mutans was investigated by real-time RT-PCR after treating with β-caryophyllene at the non-killing concentration of S. mutans.

RESULTS: The growth of S. mutans was inhibited by β-caryophyllene in above concentration of 0.078%, S. mutans biofilm was inhibited by β-caryophyllene in above 0.32%. Also, 2.5% of β-caryophyllene showed anti-biofilm activity for S. mutans biofilm. β-caryophyllene reduced the expression of gtf genes at a non-killing concentration for S. mutans. On the basis on these results, β-caryophyllene may have anti-biofilm activity and the inhibitory effect on biofilm related factor.

CONCLUSIONS: β-caryophyllene may inhibit cariogenic biofilm and may be a candidate agent for prevention of dental caries.}, } @article {pmid29407610, year = {2018}, author = {Abdullah Al, M and Gao, Y and Xu, G and Wang, Z and Warren, A and Xu, H}, title = {Trophic-functional patterns of biofilm-dwelling ciliates at different water depths in coastal waters of the Yellow Sea, northern China.}, journal = {European journal of protistology}, volume = {63}, number = {}, pages = {34-43}, doi = {10.1016/j.ejop.2018.01.003}, pmid = {29407610}, issn = {1618-0429}, mesh = {*Biodiversity ; *Biofilms ; China ; Ciliophora/*physiology ; Ecosystem ; Environmental Monitoring ; Oceans and Seas ; Population Density ; Seawater/*parasitology ; }, abstract = {Vertical variations in trophic-functional patterns of biofilm-dwelling ciliates were studied in coastal waters of the Yellow Sea, northern China. A total of 50 species were identified and assigned to four trophic-functional groups (TFgrs): algivores (A), bacterivorous (B), non-selective (N) and raptors (R). The trophic-functional structures of the ciliate communities showed significant variability among different water depths: (1) with increasing water depth, relative species numbers and relative abundances of groups A and R decreased sharply whereas those of groups B and N increased gradually; (2) in terms of the frequency of occurrences, group A dominated at depths of 1-3.5 m whereas group B dominated at 5 m, while in terms of the probability density function of the trophic-functional spectrum, group A was the highest contributor at 1 m and group B was highest at the other three depths; (3) distance-based redundancy analyses revealed significant differences in trophic-functional patterns among the four depths, except between 2 and 3.5 m (P > 0.05); and (4) the trophic-functional trait diversity increased from 1 to 3.5 m and decreased sharply at 5 m. Our results suggest that the biofilm-dwelling ciliates maintain a stable trophic-functional pattern and high biodiversity at depths of 1-3.5 m.}, } @article {pmid29407560, year = {2018}, author = {Yang, XL and Zhang, S and Li, H and Zhang, LM and Song, HL and Wang, YW}, title = {Effects of voltage on sulfadiazine degradation and the response of sul genes and microbial communities in biofilm-electrode reactors.}, journal = {Ecotoxicology and environmental safety}, volume = {151}, number = {}, pages = {272-278}, doi = {10.1016/j.ecoenv.2018.01.016}, pmid = {29407560}, issn = {1090-2414}, mesh = {Bacteria/*genetics ; *Biofilms ; Bioreactors/*microbiology ; Electrodes ; *Genes, Bacterial ; Sulfadiazine/*metabolism ; }, abstract = {Few studies have been performed on both the potential and the risks of biofilm-electrode reactors (BERs) with regard to the removal of antibiotics. This study used 33 BERs to investigate the removal rate and degradation pathway of sulfadiazine (SDZ). Furthermore, the effects of additional electrons on sul genes and microbial community composition were examined. The study found that rapid elimination rates of 20mg/L SDZ were observed during the first 3h with different DC voltage rates. Even high concentrations (160mg/L) could be rapidly removed after 24h of system operation. Pyrimidin-2ylsulfamic acid and aniline were noted to be principal products, and an SDZ degradation mechanism was proposed. The study identified 41 species of microorganism; based on bacterial community divergence caused by voltage, and six samples were grouped into four clusters. The relative abundances of sul genes from biofilm were in the following order: sulII >sulIII >sulI >sulA. The sulI, sulII, and sulA genes were enhanced with electrical stimulation in the cathode layer. It is noteworthy that sul genes were not detected in the effluent after 24h of operation.}, } @article {pmid29405142, year = {2017}, author = {John, J and Kasudhan, KS and Kanungo, R and Sharma, S and Dohe, V and Prashanth, K}, title = {Distribution of different genes responsible for invasive characteristics, detection of point mutations in capsular gene wchA and biofilm production among the invasive and non-invasive isolates of Streptococcus pneumoniae.}, journal = {Indian journal of medical microbiology}, volume = {35}, number = {4}, pages = {511-517}, doi = {10.4103/ijmm.IJMM_17_183}, pmid = {29405142}, issn = {1998-3646}, mesh = {Adolescent ; Adult ; Aged ; Bacterial Capsules/*genetics ; Biofilms/*growth & development ; Carrier State/*microbiology ; Child ; Child, Preschool ; Female ; Genetic Variation ; Healthy Volunteers ; Humans ; Infant ; Male ; Middle Aged ; Pneumococcal Infections/*microbiology ; *Point Mutation ; Polymerase Chain Reaction ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA ; Streptococcus pneumoniae/genetics/isolation & purification/*pathogenicity ; Virulence Factors/*genetics ; Young Adult ; }, abstract = {BACKGROUND: Streptococcus pneumoniae continues to cause morbidity and mortality across the globe, with developing countries bearing the brunt of the disease. It is mainly responsible for meningitis, pneumonia and septicaemia primarily in children, elderly and immunocompromised persons. Colonisation and persistence in the human nasopharynx occur during early childhood, and it appears to be prerequisite for invasive pneumococcal disease (IPD). Factors that help in persistent colonisation and subsequent invasion are ill understood. Several virulence factors have been incriminated for nasopharyngeal carriage (NC) as well as for the manifestation of the pathogenesis of IPD.

MATERIALS AND METHODS: This study attempts to characterise the S. pneumoniae isolates through analysing the distribution of different virulence markers such as lytA, ply, pbpA, eno, psaA, amiA, ciaR and wchA among the isolates obtained from disease and NC. A total of 37 isolates which include 14 invasive and 23 non-invasive isolates were investigated by polymerase chain reaction to detect the genes. Eight representative isolates were investigated for mutations in wchA by DNA sequencing that may responsible for capsular variation.

RESULTS: Ply, pbpA, amiA and eno were observed in a greater percentage of invasive isolates than non-invasive isolates though these differences are not statistically significant. Other two genes ciaH and psaA did not show any significant difference between two groups of isolates. Biofilm production was significantly higher in than non-invasive isolates when compared to invasive isolates. Sequence analysis of wchA revealed three significant point mutations or single-nucleotide polymorphisms (SNPs) among the isolates of one particular cluster (cluster III). These SNPs are responsible for a non-synonymous mutation in wchA bringing in an amino acid change in WchA protein, which is a part of the capsule of S. pneumoniae. Notably, all the three isolates present in cluster III had these SNPs and all of them were isolated from ocular infections.

CONCLUSION: The results of our study implies a possible capsular variations among the isolates and this may have an impact on capsular typing.}, } @article {pmid29405092, year = {2018}, author = {Klein, P and Sojka, M and Kucera, J and Matonohova, J and Pavlik, V and Nemec, J and Kubickova, G and Slavkovsky, R and Szuszkiewicz, K and Danek, P and Rozkot, M and Velebny, V}, title = {A porcine model of skin wound infected with a polybacterial biofilm.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {226-236}, doi = {10.1080/08927014.2018.1425684}, pmid = {29405092}, issn = {1029-2454}, mesh = {Animals ; Bacillus subtilis/growth & development ; Biofilms/*growth & development ; *Disease Models, Animal ; Enterococcus faecalis/growth & development ; Male ; Pseudomonas aeruginosa/growth & development ; Staphylococcus aureus/growth & development ; Swine ; Time Factors ; *Wound Healing ; Wound Infection/*drug therapy/*microbiology ; }, abstract = {A clinically relevant porcine model of a biofilm-infected wound was established in 10 minipigs. The wounds of six experimental animals were infected with a modified polymicrobial Lubbock chronic wound biofilm consisting of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Bacillus subtilis. Four animals served as uninfected controls. The wounds were monitored until they had healed for 24 days. The biofilm persisted in the wounds up to day 14 and significantly affected healing. The control to infected healed wound area ratios were: 45%/21%, 66%/37%, and 90%/57% on days 7, 10 and 14, respectively. The implanted biofilm prolonged inflammation, increased necrosis, delayed granulation and impaired development of the extracellular matrix as seen in histological and gene expression analyses. This model provides a therapeutic one-week window for testing of anti-biofilm treatments and for research on the pathogenesis of wound infections in pig that is clinically the most relevant animal wound healing model.}, } @article {pmid29405091, year = {2018}, author = {Rubol, S and Freixa, A and Sanchez-Vila, X and Romaní, AM}, title = {Linking biofilm spatial structure to real-time microscopic oxygen decay imaging.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {200-211}, doi = {10.1080/08927014.2017.1423474}, pmid = {29405091}, issn = {1029-2454}, mesh = {Biofilms/classification/*growth & development ; Biopolymers/analysis ; Chlorophyta/chemistry/growth & development ; Cyanobacteria/chemistry/growth & development ; Extracellular Space/chemistry ; *Image Processing, Computer-Assisted ; *Microscopy, Confocal ; Oxygen/*analysis ; }, abstract = {Two non-destructive techniques, confocal laser scanning microscopy (CLSM) and planar optode (VisiSens imaging), were combined to relate the fine-scale spatial structure of biofilm components to real-time images of oxygen decay in aquatic biofilms. Both techniques were applied to biofilms grown for seven days at contrasting light and temperature (10/20°C) conditions. The geo-statistical analyses of CLSM images indicated that biofilm structures consisted of small (~10[0] μm) and middle sized (~10[1] μm) irregular aggregates. Cyanobacteria and EPS (extracellular polymeric substances) showed larger aggregate sizes in dark grown biofilms while, for algae, aggregates were larger in light-20°C conditions. Light-20°C biofilms were most dense while 10°C biofilms showed a sparser structure and lower respiration rates. There was a positive relationship between the number of pixels occupied and the oxygen decay rate. The combination of optodes and CLMS, taking advantage of geo-statistics, is a promising way to relate biofilm architecture and metabolism at the micrometric scale.}, } @article {pmid29404277, year = {2017}, author = {Sałamaszyńska-Guz, A and Rose, S and Lykkebo, CA and Taciak, B and Bącal, P and Uśpieński, T and Douthwaite, S}, title = {Biofilm Formation and Motility Are Promoted by Cj0588-Directed Methylation of rRNA in Campylobacter jejuni.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {533}, pmid = {29404277}, issn = {2235-2988}, mesh = {Amino Acid Substitution ; Biofilms/*growth & development ; Campylobacter jejuni/*enzymology/genetics/*physiology ; Escherichia coli/genetics/metabolism ; Gene Deletion ; Gene Expression ; *Locomotion ; Methylation ; RNA, Ribosomal, 23S/*metabolism ; Recombinant Proteins/genetics/metabolism ; Virulence Factors/metabolism ; tRNA Methyltransferases/genetics/*metabolism ; }, abstract = {Numerous bacterial pathogens express an ortholog of the enzyme TlyA, which is an rRNA 2'-O-methyltransferase associated with resistance to cyclic peptide antibiotics such as capreomycin. Several other virulence traits have also been attributed to TlyA, and these appear to be unrelated to its methyltransferase activity. The bacterial pathogen Campylobacter jejuni possesses the TlyA homolog Cj0588, which has been shown to contribute to virulence. Here, we investigate the mechanism of Cj0588 action and demonstrate that it is a type I homolog of TlyA that 2'-O-methylates 23S rRNA nucleotide C1920. This same specific function is retained by Cj0588 both in vitro and also when expressed in Escherichia coli. Deletion of the cj0588 gene in C. jejuni or substitution with alanine of K[80], D[162], or K[188] in the catalytic center of the enzyme cause complete loss of 2'-O-methylation activity. Cofactor interactions remain unchanged and binding affinity to the ribosomal substrate is only slightly reduced, indicating that the inactivated proteins are folded correctly. The substitution mutations thus dissociate the 2'-O-methylation function of Cj0588/TlyA from any other putative roles that the protein might play. C. jejuni strains expressing catalytically inactive versions of Cj0588 have the same phenotype as cj0588-null mutants, and show altered tolerance to capreomycin due to perturbed ribosomal subunit association, reduced motility and impaired ability to form biofilms. These functions are reestablished when methyltransferase activity is restored and we conclude that the contribution of Cj0588 to virulence in C. jejuni is a consequence of the enzyme's ability to methylate its rRNA.}, } @article {pmid29403304, year = {2018}, author = {Neopane, P and Nepal, HP and Shrestha, R and Uehara, O and Abiko, Y}, title = {In vitro biofilm formation by Staphylococcus aureus isolated from wounds of hospital-admitted patients and their association with antimicrobial resistance.}, journal = {International journal of general medicine}, volume = {11}, number = {}, pages = {25-32}, pmid = {29403304}, issn = {1178-7074}, abstract = {INTRODUCTION: Staphylococcus aureus including methicillin-resistant S. aureus (MRSA) has the propensity to form biofilms, and causes significant mortality and morbidity in the patients with wounds. Our aim was to study the in vitro biofilm-forming ability of S. aureus isolated from wounds of hospitalized patients and their association with antimicrobial resistance.

MATERIALS AND METHODS: Forty-three clinical isolates of S. aureus were obtained from 150 pus samples using standard microbiological techniques. Biofilm formation in these isolates was detected by tissue culture plate (TCP) method and tube adherence method (TM). Antimicrobial susceptibility test was performed using the modified Kirby-Bauer disk diffusion method as per Clinical and Laboratory Standards Institute guidelines. MRSA was detected using the cefoxitin disk test.

RESULTS: Biofilm formation was observed in 30 (69.8%) and 28 (65.1%) isolates of S. aureus via TCP method and TM, respectively. Biofilm-producing S. aureus exhibited a higher incidence of antimicrobial resistance when compared with the biofilm nonproducers (P<0.05). Importantly, 86.7% of biofilm-producing S. aureus were multidrug resistant (MDR), whereas all the biofilm nonproducers were non-MDR (P<0.05). Large proportions (43.3%) of biofilm producers were identified as MRSA; however, none of the biofilm nonproducers were found to be MRSA (P<0.05).

CONCLUSION: Both the in vitro methods showed that S. aureus isolated from wound infection of hospitalized patients have high degree of biofilm-forming ability. Biofilm-producing strains have very high tendency to exhibit antimicrobial resistance, multidrug resistance and methicillin resistance. Regular surveillance of biofilm formation by S. aureus and their antimicrobial resistance profile may lead to the early treatment of the wound infection.}, } @article {pmid29401093, year = {2018}, author = {Hovis, JP and Montalvo, R and Marinos, D and Joshi, M and Shirtliff, ME and OʼToole, RV and Manson, TT}, title = {Intraoperative Vancomycin Powder Reduces Staphylococcus aureus Surgical Site Infections and Biofilm Formation on Fixation Implants in a Rabbit Model.}, journal = {Journal of orthopaedic trauma}, volume = {32}, number = {5}, pages = {263-268}, doi = {10.1097/BOT.0000000000001136}, pmid = {29401093}, issn = {1531-2291}, mesh = {Administration, Topical ; Animals ; Anti-Bacterial Agents/*administration & dosage/blood ; Biofilms/drug effects ; Disease Models, Animal ; Intraoperative Period ; Methicillin-Resistant Staphylococcus aureus/*isolation & purification ; Powders/administration & dosage ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/etiology/microbiology/*prevention & control ; Rabbits ; Staphylococcal Infections/etiology/microbiology/*prevention & control ; Surgical Wound Infection/etiology/microbiology/*prevention & control ; Tibia/microbiology/surgery ; Vancomycin/*administration & dosage/blood ; }, abstract = {OBJECTIVES: To evaluate the effectiveness of intraoperative vancomycin powder in prevention of surgical site infection and biofilm formation on implants in a contaminated animal fixation model.

METHODS: We created a rabbit surgical model including fixation implants at a tibial surgical site seeded with methicillin-resistant Staphylococcus aureus. Our study cohort included 18 rabbits. Nine received vancomycin powder at the surgical site, and the other 9 did not. Serum vancomycin levels were measured at scheduled time points over 24 hours. Bone infection and implant biofilm formation were determined based on the number of colony-forming units present 2 weeks after surgery. Radiography, histology, and electron microscopy aided in evaluation.

RESULTS: No bone infection or implant colonization occurred in the vancomycin powder group. Six bone infections and 6 implant biofilm formations (67%; 95% confidence interval, 45%-88%) occurred in the group that did not receive vancomycin powder (P = 0.009). Serum vancomycin levels were detectable at minimal levels at 1 and 6 hours only. Pathological changes occurred in the specimens that were positive for infection.

CONCLUSIONS: Intraoperative vancomycin powder application at the time of fixation decreases risk for bone infection and biofilm formation on implants in a rabbit model, with minimal increase in serum vancomycin levels. The results are encouraging and support the rationale for a clinical trial investigating the use of local vancomycin powder to reduce the rate of surgical site infections.

CLINICAL RELEVANCE: Infection is a common complication of surgery, especially with implants. Simple methods to prevent or decrease the occurrence of infection would benefit the patient and the health care system.}, } @article {pmid29399876, year = {2018}, author = {Martínez-García, S and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC}, title = {Extracellular proteases of Staphylococcus epidermidis: roles as virulence factors and their participation in biofilm.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {126}, number = {3}, pages = {177-185}, doi = {10.1111/apm.12805}, pmid = {29399876}, issn = {1600-0463}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Cell Adhesion Molecules/metabolism ; Cross Infection/microbiology/pathology ; Cysteine Proteases/*metabolism ; Humans ; Metalloendopeptidases/*metabolism ; Serine Proteases/*metabolism ; Staphylococcal Infections/microbiology/pathology ; Staphylococcus epidermidis/*enzymology/metabolism/pathogenicity ; Virulence Factors/metabolism ; }, abstract = {Staphylococci produce a large number of extracellular proteases, some of which are considered as potential virulence factors. Staphylococcus epidermidis is a causative agent of nosocomial infections in medical devices by the formation of biofilms. It has been proposed that proteases contribute to the different stages of biofilm formation. S. epidermidis secretes a small number of extracellular proteases, such as serine protease Esp, cysteine protease EcpA, and metalloprotease SepA that have a relatively low substrate specificity. Recent findings indicate a significant contribution of extracellular proteases in biofilm formation through the proteolytic inactivation of adhesion molecules. The objective of this work is to provide an overview of the current knowledge of S. epidermidis' extracellular proteases during pathogenicity, especially in the different stages of biofilm formation.}, } @article {pmid29399552, year = {2017}, author = {Shirdel, M and Tajik, H and Moradi, M}, title = {Combined Activity of Colloid Nanosilver and Zataria Multiflora Boiss Essential Oil-Mechanism of Action and Biofilm Removal Activity.}, journal = {Advanced pharmaceutical bulletin}, volume = {7}, number = {4}, pages = {621-628}, pmid = {29399552}, issn = {2228-5881}, abstract = {Purpose: The aim of this study was to investigate antimicrobial and biofilm removal potential of Zataria multiflora essential oil (ZEO) and silver nanoparticle (SNP) alone and in combination on Staphylococcus aureus and Salmonella Typhimurium and evaluate the mechanism of action. Methods: The minimum inhibitory concentration (MIC), and optimal inhibitory combination (OIC) of ZEO and SNP were determined according to fractional inhibitory concentration (FIC) method. Biofilm removal potential and leakage pattern of 260-nm absorbing material from the bacterial cell during exposure to the compounds were also investigated. Results: MICs of SNP for both bacteria were the same as 25 μg/ mL. The MICs and MBCs values of ZEO were 2500 and 1250 μg/mL, respectively. The most effective OIC value for SNP and ZEO against Salm. Typhimurium and Staph. aureus were 12.5, 625 and 0.78, 1250 μg/ mL, respectively. ZEO and SNP at MIC and OIC concentrations represented a strong removal ability (>70%) on biofilm. Moreover, ZEO at MIC and OIC concentrations did a 6-log reduction of primary inoculated bacteria during 15 min contact time. The effect of ZEO on the loss of 260-nm material from the cell was faster than SNP during 15 and 60 min. Conclusion: Combination of ZEO and SNP had significant sanitizing activity on examined bacteria which may be suitable for disinfecting the surfaces.}, } @article {pmid29398550, year = {2018}, author = {Wang, J and Rong, H and Zhang, C}, title = {Evaluation of the impact of dissolved oxygen concentration on biofilm microbial community in sequencing batch biofilm reactor.}, journal = {Journal of bioscience and bioengineering}, volume = {125}, number = {5}, pages = {532-542}, doi = {10.1016/j.jbiosc.2017.11.007}, pmid = {29398550}, issn = {1347-4421}, mesh = {Ammonia/metabolism ; Bacteria/drug effects/metabolism ; Bacterial Physiological Phenomena/*drug effects ; Batch Cell Culture Techniques/*methods ; Biofilms/*drug effects ; Bioreactors/*microbiology ; Denitrification/drug effects ; Nitrification/drug effects ; Nitrogen/metabolism ; Oxidation-Reduction ; Oxygen/metabolism/*pharmacology ; Solubility ; }, abstract = {The effect of dissolved oxygen concentration (DO) during simultaneous nitrification and denitrification (SND) was investigated in a sequencing batch biofilm reactor (SBBR). In addition, the removal rates of nitrogen and bacterial communities were investigated under different concentrations of DO (1.5, 3.5, and 4.5 mg/L). When the SND rate was 95.22%, the chemical oxygen demand and nitrogen removal was 92.22% and 84.15%, respectively, at 2.5 mg/L DO. The denitrification was inhibited by the increase of oxygen concentration. Microelectrode measurements showed that the thickness of oxygen penetration increased from 1.0 mm to 2.7 mm when the DO concentration increased from 1.5 mg/L to 5.5 mg/L. The current location of the aerobic and anaerobic layers in the biofilm was determined for analysis of the microbial community. High-throughput sequencing analysis revealed the communities of the biofilm approached similar structure and composition. Uliginosibacterium species, biofilm-forming bacteria Zoogloea species and Acinetobacter species were dominant. In the aerobic layer, phyla Betaproteobacteria and Saprospirae were predominant, the major phyla were shifted from Proteobacteria followed by Firmicutes and Bacteroidetes, which comprised 82% of the total sequences during the SND period. Anaerolineae was dominated in the anaerobic layer. The high abundance of Nitrospira in the aerobic biofilm provides evidence of the SND system performing better at ammonia oxidization. In addition, real-time PCR indicated that the amount of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) matched the Nitrospirales and Nitrosomonadales abundance well. Collectively, this study demonstrated the dynamics of key bacterial communities in the SND system were highly influenced by the DO concentration.}, } @article {pmid29398289, year = {2018}, author = {Choi, S and Kim, B and Chang, IS}, title = {Tracking of Shewanella oneidensis MR-1 biofilm formation of a microbial electrochemical system via differential pulse voltammetry.}, journal = {Bioresource technology}, volume = {254}, number = {}, pages = {357-361}, doi = {10.1016/j.biortech.2018.01.047}, pmid = {29398289}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Electrodes ; Electron Transport ; *Shewanella ; }, abstract = {In this study, the electrochemical properties of a Shewanella oneidensis MR-1 biofilm were investigated using a mini-microbial electrochemical system. The performance of the biofilm was shown, using discharge test and cyclic voltammetry investigations, to improve over time. Differential pulse voltammograms were also acquired to determine the type of extracellular electron transfer that took place and to characterize the structure of the microbial biofilm formed on the electrode of the electrochemical system. These results indicated that extracellular electron transfer via a flavin-like mediator chemical predominated as the biofilm grew. The results, combined with a comparison of the measured current density with the calculated value of a seamless single-layered biofilm, also suggested that S. oneidensis MR-1 formed a multi-layered biofilm on the electrode.}, } @article {pmid29398018, year = {2018}, author = {Jindal, S and Anand, S and Metzger, L and Amamcharla, J}, title = {Short communication: A comparison of biofilm development on stainless steel and modified-surface plate heat exchangers during a 17-h milk pasteurization run.}, journal = {Journal of dairy science}, volume = {101}, number = {4}, pages = {2921-2926}, doi = {10.3168/jds.2017-14028}, pmid = {29398018}, issn = {1525-3198}, mesh = {Animals ; *Bacterial Adhesion ; Biofilms/*growth & development ; Milk/*microbiology ; *Pasteurization/instrumentation ; Polytetrafluoroethylene ; Stainless Steel ; }, abstract = {Flow of milk through the plate heat exchanger (PHE) results in denaturation of proteins, resulting in fouling. This also accelerates bacterial adhesion on the PHE surface, eventually leading to the development of biofilms. During prolonged processing, these biofilms result in shedding of bacteria and cross-contaminate the milk being processed, thereby limiting the duration of production runs. Altering the surface properties of PHE, such as surface energy and hydrophobicity, could be an effective approach to reduce biofouling. This study was conducted to compare the extent of biofouling on native stainless steel (SS) and modified-surface [Ni-P-polytetrafluoroethylene (PTFE)] PHE during the pasteurization of raw milk for an uninterrupted processing run of 17 h. For microbial studies, raw and pasteurized milk samples were aseptically collected from inlets and outlets of both PHE at various time intervals to examine shedding of bacteria in the milk. At the end of the run, 3M quick swabs (3M, St. Paul, MN) and ATP swabs (Charm Sciences Inc., Lawrence, MA) were used to sample plates from different sections of the pasteurizers (regeneration, heating, and cooling) for biofilm screening and to estimate the efficiency of cleaning in place, respectively. The data were tested for ANOVA, and means were compared. Modified PHE experienced lower mesophilic and thermophilic bacterial attachment and biofilm formation (average log 1.0 and 0.99 cfu/cm[2], respectively) in the regenerative section of the pasteurizer compared with SS PHE (average log 1.49 and 1.47, respectively). Similarly, higher relative light units were observed for SS PHE compared with the modified PHE, illustrating the presence of more organic matter on the surface of SS PHE at the end of the run. In addition, at h 17, milk collected from the outlet of SS PHE showed plate counts of 5.44 cfu/cm[2], which were significantly higher than those for pasteurized milk collected from modified PHE (4.12 log cfu/cm[2]). This provided further evidence in favor of the modified PHE achieving better microbial quality of pasteurized milk in long process runs. Moreover, because cleaning SS PHE involves an acid treatment step, whereas an alkali treatment step is sufficient for the modified-surface PHE, use of the latter is both cost and time effective, making it a better surface for thermal processing of milk and other fluid dairy products.}, } @article {pmid29397617, year = {2018}, author = {Shi, X and Qin, YX and Wan, XY}, title = {[The research of the innate defense regulator peptide on the effects of methicillin resistant staphylococcus aureus biofilm].}, journal = {Zhonghua yi xue za zhi}, volume = {98}, number = {4}, pages = {294-298}, doi = {10.3760/cma.j.issn.0376-2491.2018.04.011}, pmid = {29397617}, issn = {0376-2491}, mesh = {Anti-Bacterial Agents ; Biofilms ; Erythromycin ; Methicillin ; *Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; }, abstract = {Objective: To investigate the destruction of the mature biofilm and the inhibitory effect of the biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) by different concentrations of the innate defense regulatory peptide (IDR-1018). Methods: 1 ×10(5)CFU /ml MRSA was inoculated uniformly into 96 well plates, the biofilm model would be completed after 48 h. Given the different concentration of IDR-1018 solution as the experimental group double diluted with tryptic soy broth (TSB), the concentration in bacteria suspension reached 3.75-1 000 mg/L respectively. Erythromycin is double diluted into different concentration gradient, combined with low concentration (15 mg/L) of IDR-1018 as the mixed group.The same amount of TSB treated as the blank control group. The growth of the biofilm was measured through the measurement of the value of absorbance (A)by the semi-quantitative method of crystal violet staining at 24 h. Using SPSS 18.0 as statistical software to analyze the data. Results: Compared with the control group (A(595)=1.764 ± 0.026), IDR-1018 significantly damaged the mature MRSA biofilm, and function was worked in a dose-dependent method. With decreasing drug concentration, the destruction of the biofilm decreased correspondingly. When the concentration was as low as 15 mg/L, A(595) = 0.946 ± 0.047(t=32.955, P<0.01). When the concentration was 7.5 mg/L, A(595) = 1.211±0.054 (t=12.731, P<0.05). When the concentration was 3.75 mg/L, A(595)=1.360±0.066(t=4.843, P<0.05), the difference was still statistically significant compared with the control group. For the immature biofilm, compared with the control group(A(595)=1.689±0.068), IDR-1018 still had a significant inhibitory effect on the formation process of MRSA biofilm when the concentration was as low as 15 mg/L (A(595)=0.846±0.057, t=34.127, P<0.01). The inhibition of biofilm had a certain decline, when the concentration was 7.5 mg/L (A(595)=1.402 ± 0.181, t=5.240, P<0.05). But the difference was still statistically significant compared with the control group. However, the inhibitory effect was significantly decreased when the concentration was 3.75 mg/L (A(595)=1.631±0.190, t=0.913, P>0.05). When the low concentration (15 mg/L) of IDR-1018 and different concentrations of erythromycin were used together, the destruction and inhibition of MRSA biofilm was significantly higher than using erythromycin or IDR-1018 alone. Conclusion: IDR-1018 can play a good inhibitory role in the formation process of MRSA biofilm, and can play a good role in destroying MRSA biofilm.}, } @article {pmid29397005, year = {2018}, author = {Rodrigues, CT and de Andrade, FB and de Vasconcelos, LRSM and Midena, RZ and Pereira, TC and Kuga, MC and Duarte, MAH and Bernardineli, N}, title = {Antibacterial properties of silver nanoparticles as a root canal irrigant against Enterococcus faecalis biofilm and infected dentinal tubules.}, journal = {International endodontic journal}, volume = {51}, number = {8}, pages = {901-911}, doi = {10.1111/iej.12904}, pmid = {29397005}, issn = {1365-2591}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/*therapeutic use ; Biofilms/*drug effects ; Cattle ; Enterococcus faecalis/*drug effects ; Gram-Positive Bacterial Infections/drug therapy ; Metal Nanoparticles/administration & dosage/*therapeutic use ; Root Canal Irrigants/*pharmacology/therapeutic use ; Silver/administration & dosage/pharmacology/*therapeutic use ; }, abstract = {AIM: To evaluate the antimicrobial action of an irrigant containing silver nanoparticles in an aqueous vehicle (AgNp), sodium hypochlorite and chlorhexidine against Enterococcus faecalis biofilm and infected dentinal tubules.

METHODOLOGY: Bovine dentine blocks were used for E. faecalis biofilm development for 21 days and irrigated with 94 ppm AgNp solution, 2.5% NaOCl and 2% chlorhexidine for 5, 15 and 30 min. For infection of dentinal tubules with E. faecalis, dentine specimens from bovine incisors were submitted to a contamination protocol over 5 days, with eight centrifugation cycles on every alternate day, and irrigated with the same solutions and time intervals used for the biofilm. The specimens were stained with the Live/Dead technique and evaluated using a confocal laser scanning microscope (CLSM). The bioImage_L software was used for measurement of the total biovolume of biofilm in μm[3] and percentage of viable bacteria (green cells) in biofilm and in dentinal tubules found after the irrigation. Statistical analyses were performed using Kruskal-Wallis and Dunn's tests for quantification of viable cells in biofilm, the Friedman test for comparisons of viable bacteria in dentinal tubules in different areas of the root canal and the Mann-Whitney U-test to compare the action of the irrigants between the two methods (P < 0.05).

RESULTS: The AgNp solution eliminated fewer bacteria, but was able to dissolve more biofilm compared with chlorhexidine (P < 0.05). NaOCl had the greatest antimicrobial activity and biofilm dissolution capacity. AgNp solution had less antimicrobial action in infected dentinal tubules compared with NaOCl (P < 0.05). The AgNp solution after 5 min was more effective in eliminating planktonic bacteria in dentinal tubules than in biofilm, but at 30 min fewer viable bacteria were observed in the biofilm compared with intratubular dentine (P < 0.05).

CONCLUSIONS: AgNp irrigant was not as effective against E. faecalis compared to solutions commonly used in root canal treatment. NaOCl is appropriate as an irrigant because it was effective in disrupting biofilm and in eliminating bacteria in biofilms and in dentinal tubules.}, } @article {pmid29396526, year = {2018}, author = {Sugimoto, S and Sato, F and Miyakawa, R and Chiba, A and Onodera, S and Hori, S and Mizunoe, Y}, title = {Broad impact of extracellular DNA on biofilm formation by clinically isolated Methicillin-resistant and -sensitive strains of Staphylococcus aureus.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {2254}, pmid = {29396526}, issn = {2045-2322}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; DNA, Bacterial/*metabolism ; Deoxyribonuclease I/metabolism ; Endopeptidase K/metabolism ; Humans ; Methicillin Resistance ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*growth & development/isolation & purification/*metabolism ; }, abstract = {Staphylococcus aureus is a major causative agent for biofilm-associated infections. Inside biofilms, S. aureus cells are embedded in an extracellular matrix (ECM) composed of polysaccharide-intercellular adhesins (PIA), proteins, and/or extracellular DNA (eDNA). However, the importance of each component and the relationship among them in biofilms of diverse strains are largely unclear. Here, we characterised biofilms formed by 47 S. aureus clinical isolates. In most (42/47) of the strains, biofilm formation was augmented by glucose supplementation. Sodium chloride (NaCl)-triggered biofilm formation was more prevalent in methicillin-sensitive S. aureus (15/24) than in methicillin-resistant strain (1/23). DNase I most effectively inhibited and disrupted massive biofilms, and Proteinase K was also effective. Anti-biofilm effects of Dispersin B, which cleaves PIA, were restricted to PIA-dependent biofilms formed by specific strains and showed significant negative correlations with those of Proteinase K, suggesting independent roles of PIA and proteins in each biofilm. ECM profiling demonstrated that eDNA was present in all strains, although its level differed among strains and culture conditions. These results indicate that eDNA is the most common component in S. aureus biofilms, whereas PIA is important for a small number of isolates. Therefore, eDNA can be a primary target for developing eradication strategies against S. aureus biofilms.}, } @article {pmid29392892, year = {2018}, author = {Skowron, K and Grudlewska, K and Krawczyk, A and Gospodarek-Komkowska, E}, title = {The effectiveness of radiant catalytic ionization in inactivation of Listeria monocytogenes planktonic and biofilm cells from food and food contact surfaces as a method of food preservation.}, journal = {Journal of applied microbiology}, volume = {124}, number = {6}, pages = {1493-1505}, doi = {10.1111/jam.13715}, pmid = {29392892}, issn = {1365-2672}, mesh = {Biofilms/*radiation effects ; Food Microbiology ; Food Preservation/*methods ; Listeria monocytogenes/*radiation effects ; Plankton/*radiation effects ; *Radiation, Ionizing ; }, abstract = {AIMS: The aim of the study was to evaluate the microbicidal effectiveness of radiant catalytic ionization (RCI) against Listeria monocytogenes strains in the form of planktonic cells and biofilm on food products and food contact surfaces as a method of food preservation.

METHODS AND RESULTS: The study material comprised six strains of L. monocytogenes, isolated from food. Samples of different types of food available by retail (raw carrot, frozen salmon filets, soft cheese) and the fragments of surfaces (stainless steel AISI 304, rubber, milled rock tiles, polypropylene) were used in the experiment. The obtained results showed the effectiveness of RCI in the inactivation of both forms of the tested L. monocytogenes strains on all the surfaces. The effectiveness of RCI for biofilm forms was lower as compared with planktonic forms. The PRR value ranged from 18·19 to 99·97% for planktonic form and from 3·92 to 70·10% for biofilm.

CONCLUSIONS: The RCI phenomenon induces the inactivation of L. monocytogenes on surfaces of food and materials used in the processing industry to a varying degree, depending on the manner of surface contamination, the properties of the contaminated materials as well as on the origin of the strain and the properties of surrounding dispersive environment in which the micro-organisms were suspended.

Searching of new actions aimed at the reduction of the microbial contamination of food and food contact surfaces are extremely important. RCI method has been already described as an effective technique of microbial and abiotic pollution removal from air. However, our studies provide new, additional data related to evaluation the RCI efficacy against microbes on different surfaces, both in planktonic and biofilm form.}, } @article {pmid29392389, year = {2018}, author = {Reen, FJ and Gutiérrez-Barranquero, JA and Parages, ML and O Gara, F}, title = {Coumarin: a novel player in microbial quorum sensing and biofilm formation inhibition.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {5}, pages = {2063-2073}, pmid = {29392389}, issn = {1432-0614}, support = {FP7-PEOPLE-2013-ITN, 607786; FP7-KBBE-2012-6, CP-TP-312184; FP7-KBBE-2012-6, 311975; OCEAN 2011-2, 287589; Marie Curie 256596; EU-634486//European Commission/ ; SSPC-2, 12/RC/2275; 13/TIDA/B2625; 12/TIDA/B2411; 12/TIDA/B2405; 14/TIDA/2438, 15/TIDA/2977//Science Foundation Ireland/Ireland ; FIRM/RSF/CoFoRD; FIRM 08/RDC/629; FIRM 1/F009/MabS; FIRM 13/F/516//Department of Agriculture, Food and the Marine/ ; PD/2011/2414; GOIPG/2014/647//Irish Research Council for Science, Engineering and Technology/ ; MRCG-2014-6//Health Research Board/Ireland ; Beaufort award C2CRA 2007/082//Marine Institute/ ; Walsh Fellowship 2013//Teagasc/ ; CF-2017-0757-P//Enterprise Ireland/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Bacterial Infections/drug therapy/*microbiology ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Coumarins/*pharmacology ; Humans ; Quorum Sensing/*drug effects ; }, abstract = {Antibiotic resistance is a growing threat worldwide, causing serious problems in the treatment of microbial infections. The discovery and development of new drugs is urgently needed to overcome this problem which has greatly undermined the clinical effectiveness of conventional antibiotics. An intricate cell-cell communication system termed quorum sensing (QS) and the coordinated multicellular behaviour of biofilm formation have both been identified as promising targets for the treatment and clinical management of microbial infections. QS systems allow bacteria to adapt rapidly to harsh conditions, and are known to promote the formation of antibiotic tolerant biofilm communities. It is well known that biofilm is a recalcitrant mode of growth and it also increases bacterial resistance to conventional antibiotics. The pharmacological properties of coumarins have been well described, and these have included several that possess antimicrobial properties. More recently, reports have highlighted the potential role of coumarins as alternative therapeutic strategies based on their ability to block the QS signalling systems and to inhibit the formation of biofilms in clinically relevant pathogens. In addition to human infections, coumarins have also been found to be effective in controlling plant pathogens, infections in aquaculture, food spoilage and in reducing biofouling caused by eukaryotic organisms. Thus, the coumarin class of small molecule natural product are emerging as a promising strategy to combat bacterial infections in the new era of antimicrobial resistance.}, } @article {pmid29390164, year = {2019}, author = {Kilinçel, Ö and Çaliskan, E and Sahin, I and Öztürk, CE and Kiliç, N and Öksüz, S}, title = {The effect of melatonin on antifungal susceptibility in planktonic and biofilm forms of Candida strains isolated from clinical samples.}, journal = {Medical mycology}, volume = {57}, number = {1}, pages = {45-51}, doi = {10.1093/mmy/myx157}, pmid = {29390164}, issn = {1460-2709}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development/isolation & purification ; Candidiasis/*microbiology ; Drug Synergism ; Humans ; Melatonin/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {In recent years, the significant increase in the isolation of antifungal resistant Candida species in presence of biofilm, have made it necessary to develop alternative agents for the treatment of these infections. In this study, the effect of antifungal susceptibility of melatonin were investigated in planktonic and biofilm forms of Candida strains isolated from the clinical samples sent to our laboratory. Biofilm formation was determined by modified microplate method. In order to determine antifungal susceptibility in biofilm-forming strains, MIC was determined by broth microdilution method in planktonic form, and MBEC values by Calgary biofilm method in biofilm form. Susceptibility tests were repeated in the presence of melatonin. Antifungal susceptibility tests repeated with antifungals combined with melatonin showed a decrease in both MIC and MBEC values; melatonin was found to be more effective especially in planktonic forms. While the most effective combination was achieved with fluconazole in the planktonic form, no statistically significant difference was found between the combinations in biofilm form. As a result, melatonin was thought to be a new alternative in the treatment of Candida infections.}, } @article {pmid29389883, year = {2018}, author = {Huang, MC and Shen, M and Huang, YJ and Lin, HC and Chen, CT}, title = {Photodynamic Inactivation Potentiates the Susceptibility of Antifungal Agents against the Planktonic and Biofilm Cells of Candida albicans.}, journal = {International journal of molecular sciences}, volume = {19}, number = {2}, pages = {}, pmid = {29389883}, issn = {1422-0067}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development/radiation effects ; Candida albicans/*drug effects/physiology/radiation effects ; Candidiasis/*drug therapy/microbiology ; Fluconazole/pharmacology ; Humans ; *Light ; Microbial Sensitivity Tests ; Photochemotherapy/methods ; Plankton/*drug effects/radiation effects ; Tolonium Chloride/pharmacology ; Triazoles/pharmacology ; }, abstract = {Photodynamic inactivation (PDI) has been shown to be a potential treatment modality against Candida infection. However, limited light penetration might leave some cells alive and undergoing regrowth. In this study, we explored the possibility of combining PDI and antifungal agents to enhance the therapeutic efficacy of Candida albicans and drug-resistant clinical isolates. We found that planktonic cells that had survived toluidine blue O (TBO)-mediated PDI were significantly susceptible to fluconazole within the first 2 h post PDI. Following PDI, the killing efficacy of antifungal agents relates to the PDI dose in wild-type and drug-resistant clinical isolates. However, only a 3-log reduction was found in the biofilm cells, suggesting limited therapeutic efficacy under the combined treatment of PDI and azole antifungal drugs. Using confocal microscopic analysis, we showed that TBO-mediated PDI could partially remove the extracellular polymeric substance (EPS) of biofilm. Finally, we showed that a combination of PDI with caspofungin could result in the complete killing of biofilms compared to those treated with caspofungin or PDI alone. These results clearly indicate that the combination of PDI and antifungal agents could be a promising treatment against C. albicans infections.}, } @article {pmid29389865, year = {2018}, author = {Price, R and Jayeola, V and Niedermeyer, J and Parsons, C and Kathariou, S}, title = {The Listeria monocytogenes Key Virulence Determinants hly and prfA are involved in Biofilm Formation and Aggregation but not Colonization of Fresh Produce.}, journal = {Pathogens (Basel, Switzerland)}, volume = {7}, number = {1}, pages = {}, pmid = {29389865}, issn = {2076-0817}, abstract = {Listeria monocytogenes has been extensively studied as a model facultative intracellular pathogen. While the roles of major virulence factors in host-pathogen interactions have been extensively characterized, recent work suggests that some of these factors can also contribute to environmental proliferation of this pathogen. In this study, we characterized two non-hemolytic transposon mutants of strain 2011L-2858 (serotype 1/2b), implicated in the 2011 listeriosis outbreak via whole cantaloupe, for their capacity to form biofilms on polystyrene, aggregate, and colonize cantaloupe rind. One mutant harbored a single mariner-based transposon insertion in hly, encoding the hemolysin Listeriolysin O, while the other harbored a single insertion in prfA, encoding PrfA, a master regulator for hly and numerous other virulence genes. Biofilm formation was significantly reduced in the prfA mutant, and to a lesser extent, in the hly mutant. Inactivation of either hly or prfA significantly reduced L. monocytogenes aggregation. However, both mutants adhered similarly to the wildtype parental strain on cantaloupe rind at either 25 or 37°C. Furthermore, growth and competitive fitness of the mutants on cantaloupe rind was not significantly impacted at either temperature. The findings suggest that, in spite of their involvement in biofilm formation and aggregation, these key virulence determinants may not be required for the ability of L. monocytogenes to colonize fresh produce.}, } @article {pmid29388540, year = {2018}, author = {Taha, M and Kohnen, C and Mallya, S and Kou, Y and Zapata, A and Ramirez-Arcos, S}, title = {Comparative characterisation of the biofilm-production abilities of Staphylococcus epidermidis isolated from human skin and platelet concentrates.}, journal = {Journal of medical microbiology}, volume = {67}, number = {2}, pages = {190-197}, doi = {10.1099/jmm.0.000673}, pmid = {29388540}, issn = {1473-5644}, mesh = {Biofilms/*growth & development ; Blood Platelets/*microbiology ; DNA, Bacterial/genetics ; Female ; Genotype ; Humans ; Male ; Phenotype ; Polymerase Chain Reaction ; Skin/*microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/classification/genetics/isolation & purification/*physiology ; }, abstract = {PURPOSE: Staphylococcus epidermidis is the predominant contaminant of platelet concentrates (PCs), a blood product used to treat patients with platelet deficiencies. This microorganism is able to form surface-attached aggregates (biofilms) in human skin. Herein, the abundance of S. epidermidis biofilm-producers in contaminated PCs compared to skin isolates was explored. Furthermore, the potential positive selection of S. epidermidis biofilm-producers during the blood donation process and PC manufacturing was investigated.

METHODOLOGY: Twenty-four S. epidermidis isolates obtained from contaminated PCs and 48 S. epidermidis isolates obtained from the venipuncture area of human volunteers were compared for their ability to form biofilms in laboratory media and in PCs using a semi quantitative crystal violet assay. Also, the presence of the biofilm-associated icaA and icaD genes was assessed by PCR-amplification.Results/Key findings.Biofilm production in laboratory media showed a higher number of S. epidermidis biofilm-producers in the skin-derived group (43.7 %) compared to the PC-derived isolates (25 %). However, all skin and PC isolates formed biofilms in PCs. The prevalence of ica-positive biofilm-producer isolates was similar in PC and skin isolates (16.6 and 18.8 %, respectively). In contrast, the abundance of ica-negative biofilm-producers was lower in PC isolates compared to skin isolates (8.3 vs 25 %, respectively).

CONCLUSION: Positive selection of S. epidermidis biofilm-producers during blood donation and PC manufacturing was not observed. Interestingly, ica-negative biofilm-producers seem to be negatively affected by skin disinfection, blood processing and PC storage. Furthermore, this study shows that S. epidermidis adopts a biofilm-forming phenotype in PCs regardless of its genetic background or origin.}, } @article {pmid29385163, year = {2018}, author = {Leitão, TJ and Cury, JA and Tenuta, LMA}, title = {Kinetics of calcium binding to dental biofilm bacteria.}, journal = {PloS one}, volume = {13}, number = {1}, pages = {e0191284}, pmid = {29385163}, issn = {1932-6203}, mesh = {*Biofilms ; Calcium/*metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Streptococcus mutans/*metabolism/physiology ; Tooth/*microbiology ; }, abstract = {Dental biofilm bacteria can bind calcium ions and release them during a pH drop, which could decrease the driving force for dental demineralization (i.e. hydroxyapatite dissolution) occurring at reduced pHs. However, the kinetics of this binding and release is not completely understood. Here we validated a method to evaluate the kinetics of calcium binding and release to/from Streptococcus mutans, and estimated the importance of this reservoir as a source of ions. The kinetics of calcium binding was assessed by measuring the amount of bound calcium in S. mutans Ingbrit 1600 pellets treated with PIPES buffer, pH 7.0, containing 1 or 10 mM Ca; for the release kinetics, bacterial pellets previously treated with 1 mM or 10 mM Ca were exposed to the calcium-free or 1 mM Ca PIPES buffer, pH 7.0, for up to 60 min. Binding and release curves were constructed and parameters of kinetics were calculated. Also, calcium release was assessed by exposing pellets previously treated with calcium to a pH 5.0 buffer for 10 min. Calcium binding to bacteria was concentration-dependent and rapid, with maximum binding reached at 5 min. On the other hand, calcium release was slower, and according to the calculations, would never be complete in the groups pretreated with 10 mM Ca. Decreasing pH from 7.0 to 5.0 caused a release of calcium able to increase the surrounding fluid calcium concentration in 2 mM. The results suggest that dental biofilm bacteria may act as a calcium reservoir, rapidly binding ions from surrounding fluids, releasing them slowly at neutral pH and promptly during a pH drop.}, } @article {pmid29383666, year = {2018}, author = {Vuotto, C and Donelli, G and Buckley, A and Chilton, C}, title = {Clostridium difficile Biofilm.}, journal = {Advances in experimental medicine and biology}, volume = {1050}, number = {}, pages = {97-115}, doi = {10.1007/978-3-319-72799-8_7}, pmid = {29383666}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects/growth & development ; Clostridioides difficile/drug effects/genetics/*physiology/ultrastructure ; Models, Biological ; }, abstract = {Clostridium difficile infection (CDI) is an important healthcare-associated disease worldwide, mainly occurring after antimicrobial therapy. Antibiotics administered to treat a number of infections can promote C. difficile colonization of the gastrointestinal tract and, thus, CDI. A rise in multidrug resistant clinical isolates to multiple antibiotics and their reduced susceptibility to the most commonly used antibiotic molecules have made the treatment of CDI more complicated, allowing the persistence of C. difficile in the intestinal environment.Gut colonization and biofilm formation have been suggested to contribute to the pathogenesis and persistence of C. difficile. In fact, biofilm growth is considered as a serious threat because of the related increase in bacterial resistance that makes antibiotic therapy often ineffective. However, although the involvement of the C. difficile biofilm in the pathogenesis and recurrence of CDI is attracting more and more interest, the mechanisms underlying biofilm formation of C. difficile as well as the role of biofilm in CDI have not been extensively described.Findings on C. difficile biofilm, possible implications in CDI pathogenesis and treatment, efficacy of currently available antibiotics in treating biofilm-forming C. difficile strains, and some antimicrobial alternatives under investigation will be discussed here.}, } @article {pmid29381248, year = {2018}, author = {Vatan, A and Saltoglu, N and Yemisen, M and Balkan, II and Surme, S and Demiray, T and Mete, B and Tabak, F and , }, title = {Association between biofilm and multi/extensive drug resistance in diabetic foot infection.}, journal = {International journal of clinical practice}, volume = {72}, number = {3}, pages = {e13060}, doi = {10.1111/ijcp.13060}, pmid = {29381248}, issn = {1742-1241}, mesh = {Adult ; Aged ; Anti-Bacterial Agents/therapeutic use ; Biofilms/*drug effects ; Diabetic Foot/*drug therapy/*microbiology ; *Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; }, abstract = {PURPOSE: We aimed to determine significant risk factors for biofilm production and to investigate the association between antimicrobial resistance profile and biofilm formation in the bacterial isolates obtained from patients with diabetic foot infection (DFI).

METHODS: Demographic, clinical, laboratory and outcome data of 165 patients, prospectively recorded and followed between January 2008 and December 2015 by a multidisciplinary committee, were analysed. Standard microbiological methods were adopted. Risk factors associated with biofilm were determined by univariate and multivariate analyses.

RESULTS: The overall rate of biofilm production among 339 wound isolates was 34%. The biofilm production rate was significantly higher in Gram-negative micro-organisms (39%) in comparison with Gram positives (21%) (P = .01). A. baumannii presented the highest biofilm production (62%), followed by P. aeruginosa (52%) and Klebsiella spp. (40%). On univariate analysis, significant factors associated with biofilm were antibiotic use within last 3 months (OR:2.94, CI: 1.5-5.75, P = .002), recurrent DFI within last 6 months (OR:2.35, CI: 1.23-4.53, P = .01), hospitalisation within last 3 months due to ipsilateral recurrent DFI (OR:2.44, CI: 1.06-5.58, P = .03), presence of amputation history (OR: 2.20, CI: 1.14-4.24, P = .01), multidrug-resistant (MDR) micro-organism (OR: 7.76, CI: 4.53-13.35, P<.001) and extensively drug-resistant (XDR) micro-organism (OR:11.33, CI:4.97-26.55, P<.001). Multivariate regression analysis revealed two variables to be significant factors associated with biofilm: MDR micro-organism (OR: 3.63, CI: 1.58-8.33, P = .002) and XDR micro-organism (OR:4.06, CI: 1.25-13.1, P = .01).

CONCLUSIONS: Multi/extensive drug resistance and previous recurrent DFIs were significantly associated with biofilm formation in patients with diabetic foot.}, } @article {pmid29380028, year = {2018}, author = {Hede, N and Khandeparker, L}, title = {Influence of Darkness and Aging on Marine and Freshwater Biofilm Microbial Communities Using Microcosm Experiments.}, journal = {Microbial ecology}, volume = {76}, number = {2}, pages = {314-327}, pmid = {29380028}, issn = {1432-184X}, support = {GAP 2429//Ballast Water Management Program, India (Ministry of Shipping and DG shipping)/ ; PSC 0105//CSIR funded Ocean Finder Program/ ; }, mesh = {Alphaproteobacteria/genetics/physiology ; Bacteria/genetics ; *Bacterial Physiological Phenomena ; Biodiversity ; *Biofilms ; Chlorophyll A/analysis ; Colony Count, Microbial ; DNA, Bacterial/genetics ; *Darkness ; Fresh Water/*microbiology ; Gammaproteobacteria/classification/genetics/physiology ; Gene Dosage ; Genes, Bacterial/genetics ; India ; Microbiota/genetics/*physiology ; Phylogeny ; Proteobacteria/classification/genetics/physiology ; RNA, Ribosomal, 16S/genetics ; Salinity ; Seawater/*microbiology ; Temperature ; }, abstract = {Ballast tank biofilms pose an additional risk of microbial invasion if sloughed off during ballasting operations, yet their significance and invasion biology is poorly understood. In this study, biofilms developed in marine and freshwater locations were exposed to prolonged darkness and aging by mimicking ballast water conditions in the laboratory. Upon prolonged darkness, the decay of phytoplankton, as indicated by the decrease in chlorophyll a in marine biofilms, led to remineralization and enhanced bacterial and protist populations. However, the same trend was not observed in the case of freshwater biofilms wherein the microbial parameters (i.e., bacteria, protists) and chlorophyll a decreased drastically. The bacterial community structure in such conditions was evaluated by real-time quantitative PCR (qPCR), and results showed that the biofilm bacterial communities changed significantly over a period of time. α-Proteobacteria was the most stable taxonomic group in the marine biofilms under dark conditions. However, β-proteobacteria dominated the freshwater biofilms and seemed to play an important role in organic matter remineralization. γ-Proteobacteria, which includes most of the pathogenic genera, were affected significantly and decreased in both the types of biofilms. This study revealed that marine biofilm communities were able to adapt better to the dark conditions while freshwater biofilm communities collapsed. Adaptation of tolerant bacterial communities, regeneration of nutrients via cell lysis, and presence of grazers appeared to be key factors for survival upon prolonged darkness. However, the fate of biofilm communities upon discharge in the new environment and their invasion potential is an important topic for future investigation.}, } @article {pmid29378892, year = {2018}, author = {Bruna, RE and Molino, MV and Lazzaro, M and Mariscotti, JF and García Véscovi, E}, title = {CpxR-Dependent Thermoregulation of Serratia marcescens PrtA Metalloprotease Expression and Its Contribution to Bacterial Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {200}, number = {8}, pages = {}, pmid = {29378892}, issn = {1098-5530}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Lipoproteins/metabolism ; Metalloendopeptidases/genetics/*metabolism ; Serratia marcescens/*enzymology/genetics ; Signal Transduction ; *Temperature ; }, abstract = {PrtA is the major secreted metalloprotease of Serratia marcescens Previous reports implicate PrtA in the pathogenic capacity of this bacterium. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug, and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression in Serratia In this work, we demonstrate that PrtA production is derepressed when the bacterial growth temperature decreases from 37°C to 30°C. We show that this thermoregulation occurs at the transcriptional level. We determined that upstream of prtA, there is a conserved motif that is directly recognized by the CpxR transcriptional regulator. This feature is found along Serratia strains irrespective of their isolation source, suggesting an evolutionary conservation of CpxR-dependent regulation of PrtA expression. We found that in S. marcescens, the CpxAR system is more active at 37°C than at 30°C. In good agreement with these results, in a cpxR mutant background, prtA is derepressed at 37°C, while overexpression of the NlpE lipoprotein, a well-known CpxAR-inducing condition, inhibits PrtA expression, suggesting that the levels of the activated form of CpxR are increased at 37°C over those at 30°C. In addition, we establish that PrtA is involved in the ability of S. marcescens to develop biofilm. In accordance, CpxR influences the biofilm phenotype only when bacteria are grown at 37°C. In sum, our findings shed light on regulatory mechanisms that fine-tune PrtA expression and reveal a novel role for PrtA in the lifestyle of S. marcescensIMPORTANCE We demonstrate that S. marcescens metalloprotease PrtA expression is transcriptionally thermoregulated. While strongly activated below 30°C, its expression is downregulated at 37°C. We found that in S. marcescens, the CpxAR signal transduction system, which responds to envelope stress and bacterial surface adhesion, is activated at 37°C and able to downregulate PrtA expression by direct interaction of CpxR with a binding motif located upstream of the prtA gene. Moreover, we reveal that PrtA expression favors the ability of S. marcescens to develop biofilm, irrespective of the bacterial growth temperature. In this context, thermoregulation along with a highly conserved CpxR-dependent modulation mechanism gives clues about the relevance of PrtA as a factor implicated in the persistence of S. marcescens on abiotic surfaces and in bacterial host colonization capacity.}, } @article {pmid29376332, year = {2018}, author = {Lee, WH and Pressman, JG and Wahman, DG}, title = {Three-Dimensional Free Chlorine and Monochloramine Biofilm Penetration: Correlating Penetration with Biofilm Activity and Viability.}, journal = {Environmental science & technology}, volume = {52}, number = {4}, pages = {1889-1898}, pmid = {29376332}, issn = {1520-5851}, support = {EPA999999//Intramural EPA/United States ; }, mesh = {Biofilms ; Chloramines ; *Chlorine ; *Disinfectants ; }, abstract = {Disinfectant biofilm penetration and its effect on biofilm aerobic activity and viability are still unclear. In this study, free chlorine and monochloramine were applied until full biofilm penetration occurred, and their effects on biofilm aerobic activity and viability were investigated in three dimensions throughout the entire biofilm depth, extending previous work where viability analysis was limited to the upper biofilm (50 μm depth), free chlorine penetration did not reach completion, and only one-dimensional (depth) profiles were obtained. The free chlorine and monochloramine biofilm concentration profiles were correlated spatially and temporally with aerobic microbial activity and cell-membrane integrity based viability using a combination of (1) microelectrode measurements for disinfectant penetration and (2) LIVE/DEAD BacLight staining, cryo-cross-sectioning, and confocal micrographs analysis for viability measurements throughout the entire biofilm depth. Compared to monochloramine, free chlorine penetration (1) was slower, (2) led to a greater decrease in biofilm thickness from sloughing, and (3) corresponded directly with a viability decrease. In addition, biofilm heterogeneity led to minor differences in either disinfectant's biofilm penetration, and prior biofilm exposure to monochloramine provided little impact to subsequent free chlorine biofilm penetration.}, } @article {pmid29375533, year = {2017}, author = {Chang, CY}, title = {Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2671}, pmid = {29375533}, issn = {1664-302X}, abstract = {Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.}, } @article {pmid29375516, year = {2017}, author = {Raghupathi, PK and Liu, W and Sabbe, K and Houf, K and Burmølle, M and Sørensen, SJ}, title = {Synergistic Interactions within a Multispecies Biofilm Enhance Individual Species Protection against Grazing by a Pelagic Protozoan.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2649}, pmid = {29375516}, issn = {1664-302X}, abstract = {Biofilm formation has been shown to confer protection against grazing, but little information is available on the effect of grazing on biofilm formation and protection in multispecies consortia. With most biofilms in nature being composed of multiple bacterial species, the interactions and dynamics of a multispecies bacterial biofilm subject to grazing by a pelagic protozoan predator were investigated. To this end, a mono and multispecies biofilms of four bacterial soil isolates, namely Xanthomonas retroflexus, Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus, were constructed and subjected to grazing by the ciliate Tetrahymena pyriformis. In monocultures, grazing strongly reduced planktonic cell numbers in P. amylolyticus and S. rhizophila and also X. retroflexus. At the same time, cell numbers in the underlying biofilms increased in S. rhizophila and X. retroflexus, but not in P. amylolyticus. This may be due to the fact that while grazing enhanced biofilm formation in the former two species, no biofilm was formed by P. amylolyticus in monoculture, either with or without grazing. In four-species biofilms, biofilm formation was higher than in the best monoculture, a strong biodiversity effect that was even more pronounced in the presence of grazing. While cell numbers of X. retroflexus, S. rhizophila, and P. amylolyticus in the planktonic fraction were greatly reduced in the presence of grazers, cell numbers of all three species strongly increased in the biofilm. Our results show that synergistic interactions between the four-species were important to induce biofilm formation, and suggest that bacterial members that produce more biofilm when exposed to the grazer not only protect themselves but also supported other members which are sensitive to grazing, thereby providing a "shared grazing protection" within the four-species biofilm model. Hence, complex interactions shape the dynamics of the biofilm and enhance overall community fitness under stressful conditions such as grazing. These emerging inter- and intra-species interactions could play a vital role in biofilm dynamics in natural environments like soil or aquatic systems.}, } @article {pmid29375501, year = {2017}, author = {Martins, SJ and Medeiros, FHV and Lakshmanan, V and Bais, HP}, title = {Impact of Seed Exudates on Growth and Biofilm Formation of Bacillus amyloliquefaciens ALB629 in Common Bean.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2631}, pmid = {29375501}, issn = {1664-302X}, abstract = {We aimed to unravel the events which favor the seed-rhizobacterium Bacillus amyloliquefaciens strain ALB629 (hereafter ALB629) interaction and which may interfere with the rhizobacterium colonization and growth on the spermosphere of common bean. Seed exudates from common bean were tested in vitro for ALB629 biofilm formation and bacterial growth. Furthermore, the performance of ALB629 on plant-related variables under drought stress was checked. Seed exudates (1 and 5% v/v) increased ALB629 biofilm formation. Additionally, the colony forming units for ALB629 increased both in culture and on the bean seed surface. The bean seed exudates up-regulated biofilm operons in ALB629 TasA and EpsD by ca. two and sixfold, respectively. The high-performance liquid chromatography (HPLC)-coupled with MS showed that malic acid is present as a major organic acid component in the seed exudates. Seeds treated with ALB629 and amended with malic acid resulted in seedlings with a higher bacterial concentration, induced plant drought tolerance, and promoted plant growth. We showed that seed exudates promote growth of ALB629 and malic acid was identified as a major organic acid component in the bean seed exudates. Our results also show that supplementation of ALB629 induced drought tolerance and growth in plants. The research pertaining to the biological significance of seed exudates in plant-microbe interaction is unexplored field and our work shows the importance of seed exudates in priming both growth and tolerance against abiotic stress.}, } @article {pmid29374577, year = {2018}, author = {El Haj, C and Murillo, O and Ribera, A and Lloberas, N and Gómez-Junyent, J and Tubau, F and Fontova, P and Cabellos, C and Ariza, J}, title = {Evaluation of linezolid or trimethoprim/sulfamethoxazole in combination with rifampicin as alternative oral treatments based on an in vitro pharmacodynamic model of staphylococcal biofilm.}, journal = {International journal of antimicrobial agents}, volume = {51}, number = {6}, pages = {854-861}, doi = {10.1016/j.ijantimicag.2018.01.014}, pmid = {29374577}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Drug Combinations ; Humans ; Linezolid/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/drug therapy/microbiology ; Rifampin/*pharmacology ; Sulfamethizole/*pharmacology ; Trimethoprim/*pharmacology ; }, abstract = {Combinations of linezolid (LZD) or trimethoprim/sulfamethoxazole (SXT) plus rifampicin (RIF) are alternative oral treatments for staphylococcal prosthetic joint infections (PJIs) when fluoroquinolones are not possible to use, but there is limited evidence regarding their activity. This study evaluated the efficacy of LZD and SXT, alone and in combination with RIF, against Staphylococcus aureus in an in vitro pharmacokinetic/pharmacodynamic biofilm model. Using the CDC Biofilm Reactor[®] system, simulated regimens of LZD (600 mg every 12 h), SXT (160/800 mg every 8 h) and levofloxacin (LVX) (750 mg/day), alone and in combination with RIF (600 mg/day), were evaluated against one methicillin-susceptible S. aureus (MSSA) and one methicillin-resistant S. aureus (MRSA) strain. Antibiotic efficacy was evaluated by the decrease in planktonic bacterial counts from medium and biofilm-embedded bacteria from coupons over 56 h. Resistant strains were screened. In both strains, SXT alone was ineffective and LZD presented low activity, but no resistance emerged. Combinations with RIF significantly increased the antibiofilm efficacy against MSSA (Δlog CFU/mL 56h-0h: SXT + RIF, -2.9 and LZD + RIF, -3.1), but RIF-resistant strains appeared with SXT + RIF. Against MRSA, LZD + RIF (-3.1) protected against the emergence of resistance and was more effective than SXT + RIF (-0.6; P <0.05), in which RIF-resistant strains were again detected. LVX + RIF confirmed its high efficacy against biofilm-embedded bacteria, this being the most effective therapy (-5.1 against MSSA). The emergence of RIF-resistant strains with SXT + RIF poses serious concerns for its use in clinical practice. Interestingly, LZD + RIF appears to be an appropriate alternative for PJI caused by LVX-resistant S. aureus.}, } @article {pmid29373594, year = {2018}, author = {Grimm, I and Dumke, J and Dreier, J and Knabbe, C and Vollmer, T}, title = {Biofilm formation and transcriptome analysis of Streptococcus gallolyticus subsp. gallolyticus in response to lysozyme.}, journal = {PloS one}, volume = {13}, number = {1}, pages = {e0191705}, pmid = {29373594}, issn = {1932-6203}, mesh = {*Biofilms ; Muramidase/*metabolism ; Streptococcus gallolyticus subspecies gallolyticus/genetics/*metabolism ; *Transcriptome ; }, abstract = {Streptococcus gallolyticus subsp. gallolyticus is a commensal bacterium of the human gastrointestinal tract, and a pathogen causing infective endocarditis and other biofilm-associated infections via exposed collagen. This study focuses on the characterization of the biofilm formation and collagen adhesion of S. gallolyticus subsp. gallolyticus under different conditions. In this study, it has been observed that the isolate UCN 34 is resistant to 20 mg/ml lysozyme in BHI medium, whereas the strain BAA-2069 builds more biofilm in the presence of lysozyme compared to in a control of BHI without lysozyme. A transcriptome analysis with whole genome microarrays of these two isolates in BHI medium with lysozyme compared to control without lysozyme revealed changes in gene expression levels. In the isolate BAA-2069, 67 genes showed increased expression in the presence of lysozyme, while in the isolate UCN 34, 165 genes showed increased expression and 30 genes showed decreased expression through lysozyme treatment. Products of genes which were higher expressed are in involved in transcription and translation, in cell-wall modification, in hydrogen peroxide resistance and in bacterial immunity. Furthermore, the adhesion ability of different strains of S. gallolyticus subsp. gallolyticus to collagen type I and IV was analyzed. Thereby, we compared the adhesion of 46 human isolates with 23 isolates from animals. It was shown that the adhesion ability depends significantly on whether the isolate was isolated from human or animal. For example, high adhesion ability was observed for strain UCN 34 isolated from an infective endocarditis patient, whereas strain DSM 16831 isolated from koala feces adhered only marginally to collagen. Full genome microarray analysis of these two strains revealed strain-dependent gene expression due to adhesion. The expression of 25 genes of a transposon and 15 genes of a phage region in strain DSM 16831 were increased, which corresponds to horizontal gene transfer. Adherence to collagen in strain UCN 34 led to higher expression of 27 genes and lower expression of 31 genes. This was suggestive of a change in nutrient uptake.}, } @article {pmid29372520, year = {2018}, author = {Wang, JH and Li, HY and Chen, YP and Liu, SY and Yan, P and Shen, Y and Guo, JS and Fang, F}, title = {Estimation of oxygen effective diffusion coefficient in a non-steady-state biofilm based on response time.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {10}, pages = {9797-9805}, pmid = {29372520}, issn = {1614-7499}, support = {cstc2014yykfC20001//Chongqing Science and Technology Commission/ ; cstc2015shms-ztzx20001//Chongqing Science and Technology Commission/ ; 2015ZX07103-007//National Key Project of China/ ; }, mesh = {Aerobiosis ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Diffusion ; Microelectrodes ; *Models, Theoretical ; Oxygen/*analysis ; Time Factors ; Water Purification/instrumentation/*methods ; }, abstract = {In wastewater treatment, oxygen effective diffusion coefficient (D eff) is a key parameter in the study of oxygen diffusion-reaction process and mechanism in biofilms. Almost all the reported methods for estimating the D eff rely on other biokinetic parameters, such as substrate consumption rate and reaction rate constant. Then, the estimation was complex. In this study, a method independent of other biokinetic parameters was proposed for estimating the dissolved oxygen (DO) D eff in biofilms. It was based on the dynamic DO microdistribution in a non-steady-state inactive biofilm, which was measured by the oxygen transfer modeling device (OTMD) combining with an oxygen microelectrode system. A pure DO diffusion model was employed, and the expression of the DO D eff was obtained by applying the analytical solution of the model to a selected critical DO concentration. DO D eff in the biofilm from the bioreactor was calculated as (1.054 ± 0.041) × 10[-9] m[2]/s, and it was in the same order of magnitude with the reported results. Therefore, the method proposed in this study was effective and feasible. Without measurement of any other biokinetic parameters, this method was convenient and will benefit the study of oxygen transport-reaction process in biofilms and other biofouling deposits. Graphical abstract ᅟ.}, } @article {pmid29372248, year = {2018}, author = {Rieth, KKS and Gill, SR and Lott-Limbach, AA and Merkley, MA and Botero, N and Allen, PD and Miller, MC}, title = {Prevalence of High-Risk Human Papillomavirus in Tonsil Tissue in Healthy Adults and Colocalization in Biofilm of Tonsillar Crypts.}, journal = {JAMA otolaryngology-- head & neck surgery}, volume = {144}, number = {3}, pages = {231-237}, pmid = {29372248}, issn = {2168-619X}, mesh = {Adult ; Biofilms ; Cross-Sectional Studies ; Female ; Humans ; In Situ Hybridization ; Male ; Palatine Tonsil/*virology ; Papillomaviridae/*isolation & purification ; Papillomavirus Infections/*epidemiology ; Polymerase Chain Reaction ; Prevalence ; Retrospective Studies ; }, abstract = {IMPORTANCE: The pathogenesis of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma is currently an important topic of elucidation. The presence of latent HPV infection in tonsil tissue of healthy adults may provide an explanation for a component of this process and contribute to the understanding of HPV-associated squamous cell carcinoma oncogenesis of the oropharynx.

OBJECTIVE: To determine the prevalence of oropharyngeal HPV and to determine the spatial relationship between the virus and crypt biofilm in tonsil tissue.

A retrospective, cross-sectional study was carried out using samples obtained from tonsils that were archived at a university hospital following elective nononcologic tonsillectomy from 2012 to 2015. Samples consisted of formalin-fixed paraffin embedded samples of tumor-free tonsil tissue from 102 adults between the ages of 20 and 39 years.

EXPOSURES: Human papillomavirus status was assessed by polymerase chain reaction, and high-risk subtypes 16 and 18 were assessed with quantitative polymerase chain reaction assay. Samples that demonstrated presence of HPV were then analyzed by in situ hybridization to localize the viral capsid protein. These samples were then stained with concanavalin A to establish biofilm presence and morphology. These samples were also stained with diamidino-phenylindole (DAPI) to visualize location of the virus in relation to cell nuclei. These data were then assembled for aggregate analysis to colocalize HPV in the biofilm of the tonsillar crypts.

MAIN OUTCOMES AND MEASURES: Outcome measurements were determined prior to data collection and include prevalence of high-risk HPV types 16 and 18 in tonsil tissue of otherwise healthy adults, as well as demonstration with immunohistochemistry of HPV in tonsillar crypt biofilm.

RESULTS: In 102 otherwise healthy adults (55 [53.9%] female; age range, 20-39 years), the overall prevalence of HPV in tonsils was 4.9% (n = 5); and high-risk type 16 or 18, 3.9% (n = 4). In this sample population, in situ hybridization colocalized HPV virus to the biofilm of the tonsillar crypts.

CONCLUSIONS AND RELEVANCE: Biofilm is present in the tonsillar crypts in a considerable proportion of tonsil tissues and may be reproducibly identified. Human papillomavirus is demonstrated to colocalize to the crypt biofilm. This has important implications with respect to the determination of HPV prevalence rates in the oropharynx. It may also play a role in the pathogenesis of HPV-related oropharyngeal carcinoma.}, } @article {pmid29372142, year = {2017}, author = {Ren, GX and Guo, XP and Sun, YC}, title = {Corrigendum: HmsC Controls Yersinia pestis Biofilm Formation in Response to Redox Environment.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {525}, doi = {10.3389/fcimb.2017.00525}, pmid = {29372142}, issn = {2235-2988}, abstract = {[This corrects the article on p. 355 in vol. 7, PMID: 28848715.].}, } @article {pmid29371566, year = {2017}, author = {Nazik, H and Choudhary, V and Stevens, DA}, title = {Verapamil Inhibits Aspergillus Biofilm, but Antagonizes Voriconazole.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {3}, number = {3}, pages = {}, pmid = {29371566}, issn = {2309-608X}, abstract = {The paucity of effective antifungals against Aspergillus and increasing resistance, the recognition of the importance of Aspergillus biofilm in several clinical settings, and reports of verapamil-a calcium channel blocker-efficacy against Candida biofilm and hyphal growth, and synergy with an azole antifungal in vitro, led to a study of verapamil ± voriconazole against Aspergillus. Broth macrodilution methodology was utilized for MIC (minimum inhibitory concentration) and MFC (minimum fungicidal concentration) determination. The metabolic effects (assessed by XTT [2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt]) on biofilm formation by conidia were studied upon exposure to verapamil, verapamil plus voriconazole, or voriconazole alone. For biofilm formation, we found less inhibition from the combinations than with either drug alone, or less inhibition from the combination than that of the more potent drug alone. For preformed biofilm, we found no significant change in activity comparing voriconazole alone compared to added verapamil, and no significant alteration of activity of the more potent voriconazole, at any concentration in the range tested, by addition of a concentration of verapamil that is inhibitory alone. In full checkerboard assays with planktonic fungus, there was no indication of any effect of one drug on the other (indifference). Although verapamil was similarly inactive against planktonic Aspergillus, as with Candida, verapamil was indeed active against Aspergillus biofilm. However, indifference and antagonism was found with voriconazole.}, } @article {pmid29371559, year = {2017}, author = {Korem, M and Kagan, S and Polacheck, I}, title = {The Effect of Novel Heterocyclic Compounds on Cryptococcal Biofilm.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {3}, number = {3}, pages = {}, pmid = {29371559}, issn = {2309-608X}, abstract = {Biofilm formation by microorganisms depends on their communication by quorum sensing, which is mediated by small diffusible signaling molecules that accumulate in the extracellular environment. During human infection, the pathogenic yeast Cryptococcus neoformans can form biofilm on medical devices, which protects the organism and increases its resistance to antifungal agents. The aim of this study was to test two novel heterocyclic compounds, S-8 (thiazolidinedione derivative, TZD) and NA-8 (succinimide derivative, SI), for their anti-biofilm activity against strains of Cryptococcus neoformans and Cryptococcus gattii. Biofilms were formed in a defined medium in 96-well polystyrene plates and 8-well micro-slides. The effect of sub-inhibitory concentrations of S-8 and NA-8 on biofilm formation was measured after 48 h by a metabolic reduction assay and by confocal laser microscopy analysis using fluorescent staining. The formation and development of cryptococcal biofilms was inhibited significantly by these compounds in concentrations below the minimum inhibitory concentration (MIC) values. These compounds may have a potential role in preventing fungal biofilm development on indwelling medical devices or even as a therapeutic measure after the establishment of biofilm.}, } @article {pmid29371532, year = {2017}, author = {McCall, A and Edgerton, M}, title = {Real-Time Approach to Flow Cell Imaging of Candida albicans Biofilm Development.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {3}, number = {1}, pages = {}, pmid = {29371532}, issn = {2309-608X}, support = {F31 DE024346/DE/NIDCR NIH HHS/United States ; R01 DE010641/DE/NIDCR NIH HHS/United States ; R01 DE022720/DE/NIDCR NIH HHS/United States ; T32 DE023526/DE/NIDCR NIH HHS/United States ; }, abstract = {The ability of Candida albicans to form biofilms is a virulence factor that allows tissue attachment and subsequent infection of host tissues. Fungal biofilms have been particularly well studied, however the vast majority of these studies have been conducted under static conditions. Oral biofilms form in the presence of salivary flow, therefore we developed a novel flow system used for real-time imaging of fungal biofilm development. C. albicans wild-type (WT) cells readily attached to the substrate surface during the 2 h attachment phase, then formed heterogeneous biofilms after 18 h flow. Quantitative values for biomass, rates of attachment and detachment, and cell-cell adhesion events were obtained for C. albicans WT cells and for a hyperfilamentous mutant Δhog1. Attachment rates of C. albicans WT cells were nearly 2-fold higher than C. albicans Δhog1 cells, although Δhog1 cells formed 4-fold higher biomass. The reduced normalized detachment rate was the primary factor responsible for the increased biomass of Δhog1 biofilm, showing that cell detachment rates are an important predictor for ultimate biofilm mass under flow. Unlike static biofilms, C. albicans cells under constant laminar flow undergo continuous detachment and seeding that may be more representative of the development of in vivo biofilms.}, } @article {pmid29371526, year = {2017}, author = {Rosenblatt, J and Reitzel, RA and Vargas-Cruz, N and Chaftari, AM and Hachem, R and Raad, II}, title = {Comparative Efficacies of Antimicrobial Catheter Lock Solutions for Fungal Biofilm Eradication in an in Vitro Model of Catheter-Related Fungemia.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {3}, number = {1}, pages = {}, pmid = {29371526}, issn = {2309-608X}, abstract = {Fungal catheter-related bloodstream infections (CRBSIs)-primarily due to Candida species-account for over 12% of all CRBSIs, and have been progressively increasing in prevalence. They present significant health and economic burdens, and high mortality rates. Antimicrobial catheter lock solutions are an important prophylactic option for preventing fungal CRBSIs. In this study, we compared the effectiveness of two FDA-approved catheter lock solutions (heparin and saline) and three experimental antimicrobial catheter lock solutions-30% citrate, taurolidine-citrate-heparin (TCH), and nitroglycerin-citrate-ethanol (NiCE)-in an in vitro model of catheters colonized by fungi. The fungi tested were five different strains of Candida clinical isolates from cancer patients who contracted CRBSIs. Time-to-biofilm-eradication was assessed in the model with 15, 30, and 60 min exposures to the lock solutions. Only the NiCE lock solution was able to fully eradicate all fungal biofilms within 60 min. Neither 30% citrate nor TCH was able to fully eradicate any of the Candida biofilms in this time frame. The NiCE lock solution was significantly superior to TCH in eradicating biofilms of five different Candida species (p = 0.002 for all).}, } @article {pmid29371509, year = {2018}, author = {Sav, H and Rafati, H and Öz, Y and Dalyan-Cilo, B and Ener, B and Mohammadi, F and Ilkit, M and van Diepeningen, AD and Seyedmousavi, S}, title = {Biofilm Formation and Resistance to Fungicides in Clinically Relevant Members of the Fungal Genus Fusarium.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {4}, number = {1}, pages = {}, pmid = {29371509}, issn = {2309-608X}, abstract = {Clinically relevant members of the fungal genus, Fusarium, exhibit an extraordinary genetic diversity and cause a wide spectrum of infections in both healthy individuals and immunocompromised patients. Generally, Fusarium species are intrinsically resistant to all systemic antifungals. We investigated whether the presence or absence of the ability to produce biofilms across and within Fusarium species complexes is linked to higher resistance against antifungals. A collection of 41 Fusarium strains, obtained from 38 patients with superficial and systemic infections, and three infected crops, were tested, including 25 species within the Fusarium fujikuroi species complex, 14 from the Fusarium solani species complex (FSSC), one Fusarium dimerum species complex, and one Fusarium oxysporum species complex isolate. Of all isolates tested, only seven strains from two species of FSSC, five F. petroliphilum and two F. keratoplasticum strains, recovered from blood, nail scrapings, and nasal biopsy samples, could produce biofilms under the tested conditions. In the liquid culture tested, sessile biofilm-forming Fusarium strains exhibited elevated minimum inhibitory concentrations (MICs) for amphotericin B, voriconazole, and posaconazole, compared to their planktonic counterparts, indicating that the ability to form biofilm may significantly increase resistance. Collectively, this suggests that once a surface adherent biofilm has been established, therapies designed to kill planktonic cells of Fusarium are ineffective.}, } @article {pmid29371505, year = {2018}, author = {Kean, R and Delaney, C and Rajendran, R and Sherry, L and Metcalfe, R and Thomas, R and McLean, W and Williams, C and Ramage, G}, title = {Gaining Insights from Candida Biofilm Heterogeneity: One Size Does Not Fit All.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {4}, number = {1}, pages = {}, pmid = {29371505}, issn = {2309-608X}, support = {//Wellcome Trust/United Kingdom ; }, abstract = {Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us.}, } @article {pmid29370419, year = {2018}, author = {Moreno-García, J and Coi, AL and Zara, G and García-Martínez, T and Mauricio, JC and Budroni, M}, title = {Study of the role of the covalently linked cell wall protein (Ccw14p) and yeast glycoprotein (Ygp1p) within biofilm formation in a flor yeast strain.}, journal = {FEMS yeast research}, volume = {18}, number = {2}, pages = {}, doi = {10.1093/femsyr/foy005}, pmid = {29370419}, issn = {1567-1364}, mesh = {*Biofilms ; Cell Wall/genetics/*metabolism ; Fermentation ; Fungal Proteins/genetics/*metabolism ; Membrane Glycoproteins/genetics/*metabolism ; Mutation ; Saccharomyces cerevisiae/physiology ; Saccharomyces cerevisiae Proteins/genetics/metabolism ; Wine ; Yeasts/*physiology ; }, abstract = {Flor yeasts are Saccharomyces cerevisiae strains noted by their ability to create a type of biofilm in the air-liquid interface of some wines, known as 'flor' or 'velum', for which certain proteins play an essential role. Following a proteomic study of a flor yeast strain, we deleted the CCW14 (covalently linked cell wall protein) and YGP1 (yeast glycoprotein) genes-codifying for two cell surface glycoproteins-in a haploid flor yeast strain and we reported that both influence the weight of the biofilm as well as cell adherence (CCW14).}, } @article {pmid29370284, year = {2018}, author = {Carrel, M and Beltran, MA and Morales, VL and Derlon, N and Morgenroth, E and Kaufmann, R and Holzner, M}, title = {Correction: Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools.}, journal = {PloS one}, volume = {13}, number = {1}, pages = {e0192099}, pmid = {29370284}, issn = {1932-6203}, abstract = {[This corrects the article DOI: 10.1371/journal.pone.0180374.].}, } @article {pmid29368511, year = {2018}, author = {Chang, JD and Wallace, AG and Foster, EE and Kim, SJ}, title = {Peptidoglycan Compositional Analysis of Enterococcus faecalis Biofilm by Stable Isotope Labeling by Amino Acids in a Bacterial Culture.}, journal = {Biochemistry}, volume = {57}, number = {7}, pages = {1274-1283}, pmid = {29368511}, issn = {1520-4995}, support = {R01 GM116130/GM/NIGMS NIH HHS/United States ; }, mesh = {Acetylation ; Amino Acids/*analysis ; *Biofilms/growth & development ; Cell Wall/*chemistry ; Endopeptidases/chemistry ; Enterococcus faecalis/*chemistry/physiology ; Isotope Labeling/methods ; Peptidoglycan/*analysis ; Plankton/microbiology ; Spectrometry, Mass, Electrospray Ionization/methods ; }, abstract = {Peptidoglycan (PG) is a major component of the cell wall in Enterococcus faecalis. Accurate analysis of PG composition provides crucial insights into the bacterium's cellular functions and responses to external stimuli, but this analysis remains challenging because of various chemical modifications to PG-repeat subunits. We characterized changes to the PG composition of E. faecalis grown as planktonic bacteria and biofilm by developing "stable isotope labeling by amino acids in bacterial culture" (SILAB), optimized for bacterial cultures with incomplete amino acid labeling. This comparative analysis by mass spectrometry was performed by labeling E. faecalis in biofilm with heavy Lys (l-[[13]C6,[2]D9,[15]N2]Lys) and planktonic bacteria with natural abundance l-Lys, then mixing equal amounts of bacteria from each condition, and performing cell wall isolation and mutanolysin digestion necessary for liquid chromatography and mass spectrometry. An analytical method was developed to determine muropeptide abundances using correction factors to compensate for incomplete heavy Lys isotopic enrichment (98.33 ± 0.05%) and incorporation (83.23 ± 1.16%). Forty-seven pairs of PG fragment ions from isolated cell walls of planktonic and biofilm samples were selected for SILAB analysis. We found that the PG in biofilm showed an increased level of PG cross-linking, an increased level of N-deacetylation of GlcNAc, a decreased level of O-acetylation of MurNAc, and an increased number of stem modifications by d,d- and l,d-carboxypeptidases.}, } @article {pmid29367158, year = {2018}, author = {Zhang, Q and Li, X and Guo, D and Ye, T and Xiong, M and Zhu, L and Liu, C and Jin, S and Hu, Z}, title = {Operation of a vertical algal biofilm enhanced raceway pond for nutrient removal and microalgae-based byproducts production under different wastewater loadings.}, journal = {Bioresource technology}, volume = {253}, number = {}, pages = {323-332}, doi = {10.1016/j.biortech.2018.01.014}, pmid = {29367158}, issn = {1873-2976}, mesh = {Biofilms ; *Biofuels ; Biomass ; *Microalgae ; Ponds ; *Wastewater ; }, abstract = {In this study, a vertical-algal-biofilm-enhanced raceway pond (VAB-enhanced raceway pond) was designed and assessed for wastewater treatment and algal biomass production under different nutrient loading rates. Results indicated that the maximum removal capacity of the system was accordingly 7.52, 6.76 and 0.11 g·m[-2]·day[-1] for COD, TN and TP, under which the wastewater effluent concentration could be respectively reduced from 106.00, 92.71 and 1.48 mg/L to 43.5, 11.03 and 0.46 mg/L in continuous mode. Meanwhile, about 7.47-10.10 t·ha[-1]·year[-1] of lipid, 14.85-23.01 t·ha[-1]·year[-1] of protein and 10.69-14.20 t·ha[-1]·year[-1] of carbohydrate could be produced from the algae by the system in large scale. The corresponding estimated stoichiometric-methane-potential and biodiesel production of the harvested biomass was 21,471-29,136 m[3]·ha[-1]·year[-1] and 0.57-1.15 t·ha[-1]·year[-1], respectively. The findings of this study demonstrate the feasibility of using VAB-enhanced raceway pond for economically and cost-effectively recovery of nutrients from the wastewater via algal-based byproducts production.}, } @article {pmid29366864, year = {2018}, author = {Neethu, S and Midhun, SJ and Radhakrishnan, EK and Jyothis, M}, title = {Green synthesized silver nanoparticles by marine endophytic fungus Penicillium polonicum and its antibacterial efficacy against biofilm forming, multidrug-resistant Acinetobacter baumanii.}, journal = {Microbial pathogenesis}, volume = {116}, number = {}, pages = {263-272}, doi = {10.1016/j.micpath.2018.01.033}, pmid = {29366864}, issn = {1096-1208}, mesh = {Acinetobacter baumannii/*drug effects/physiology ; Anti-Bacterial Agents/*metabolism/pharmacology ; Biofilms/*growth & development ; Chlorophyta/microbiology ; Colony Count, Microbial ; Drug Resistance, Multiple, Bacterial ; Endophytes/isolation & purification/metabolism ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Transmission ; Penicillium/isolation & purification/*metabolism ; Silver/*metabolism/pharmacology ; Spectrophotometry ; Spectroscopy, Fourier Transform Infrared ; Spectrum Analysis, Raman ; }, abstract = {Acinetobacter baumanii, a gram-negative, non-motile, encapsulated coccobacillus which causes infections worldwide. The objective of this study was to find a fungal strain that could be utilized to biosynthesize antibacterial silver nanoparticles (AgNPs) against Acinetobacter baumanii. The present investigation explains rapid and extracellular biosynthesis of silver nanoparticles by the algicolous endophytic fungus, Penicillium polonicum, isolated from the marine green alga Chetomorpha antennina. The obtained silver nanoparticles were characterized by UV-Vis spectroscopy, Raman spectroscopy, Fourier transformation infrared (FTIR), and Transmission electron microscopy (TEM). The SNPs showed a characteristic UV- visible peak at 430 nm with an average size of 10-15 nm. As evident from the FTIR and Raman spectra, possibly the protein components of fungal extract have caused the reduction of silver nitrate. Parametric optimization, including the concentration of AgNO3, ratio of cell filtrate and AgNO3, fungal biomass, reaction time, pH, and presence of light, was done for rapid AgNPs production. The antibacterial efficacy of AgNPs against multi-drug-resistant, biofilm-forming Acinetobacter baumanii, was evaluated by well diffusion assay. The Minimum inhibitory concentration (MIC) of AgNP was 15.62 μgml[-1] and the minimum bactericidal concentration (MBC) was 31.24 μgml[-1]. Killing kinetic assay revealed complete killing of the bacterial cells within 6 h. Log reduction and percent survival of bacterial cells were analyzed from killing kinetic study. Bactericidal nature of synthesized nanoparticles was confirmed by fluorescent microscopical analysis. The effect of AgNPs on the ultrastructure of bacterial pathogen was evaluated by Transmission electron microscopy.}, } @article {pmid29364253, year = {2017}, author = {Santigli, E and Koller, M and Klug, B}, title = {Oral Biofilm Sampling for Microbiome Analysis in Healthy Children.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {130}, pages = {}, pmid = {29364253}, issn = {1940-087X}, mesh = {Biofilms/*growth & development ; Child ; Humans ; Microbiota/*physiology ; Mouth/*microbiology ; }, abstract = {Oral biofilm and its molecular analysis provide a basis for investigating various dental research and clinical questions. Knowledge of biofilm composition leads to a better understanding of cariogenic and periopathogenic mechanisms. Microbial changes taking place in the oral cavity during childhood are of interest for several reasons. The evolution of the child oral microbiota and shifts in its composition need to be analyzed further to understand and possibly prevent the onset of disease. At the same time, advanced knowledge of the natural composition of oral biofilm is needed. Early stages of caries-free permanent dentition with healthy gums provide a widely unaffected subgingival habitat that can serve as an in situ baseline for studying features of oral health and disease. Analysis of children's oral biofilm during different stages in life is thus an important theme in the field. Modern molecular analysis methods can provide comprehensive information about the bacterial diversity of such biofilms. To enable microbiota data comparison, it is important to standardize each step in the procedure for molecular data generation. This procedure spans from clinical sampling, Next Generation Sequencing (NGS), bioinformatic data processing, to taxonomic interpretation. One of the most critical factors here is biofilm sampling. Sampling in children is even more challenging in particular due to limited space in subgingival areas. We thus focus on the use of paper points for subgingival sampling. This article provides a detailed protocol for oral biofilm sampling of the subgingival sulcus, the mucosa, and saliva in children.}, } @article {pmid29362474, year = {2018}, author = {Wong, EHJ and Ng, CG and Goh, KL and Vadivelu, J and Ho, B and Loke, MF}, title = {Metabolomic analysis of low and high biofilm-forming Helicobacter pylori strains.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {1409}, pmid = {29362474}, issn = {2045-2322}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Chromatography, Liquid ; Helicobacter pylori/metabolism/*physiology ; Metabolomics/*methods ; Principal Component Analysis ; Tandem Mass Spectrometry ; }, abstract = {The biofilm-forming-capability of Helicobacter pylori has been suggested to be among factors influencing treatment outcome. However, H. pylori exhibit strain-to-strain differences in biofilm-forming-capability. Metabolomics enables the inference of spatial and temporal changes of metabolic activities during biofilm formation. Our study seeks to examine the differences in metabolome of low and high biofilm-formers using the metabolomic approach. Eight H. pylori clinical strains with different biofilm-forming-capability were chosen for metabolomic analysis. Bacterial metabolites were extracted using Bligh and Dyer method and analyzed by Liquid Chromatography/Quadrupole Time-of-Flight mass spectrometry. The data was processed and analyzed using the MassHunter Qualitative Analysis and the Mass Profiler Professional programs. Based on global metabolomic profiles, low and high biofilm-formers presented as two distinctly different groups. Interestingly, low-biofilm-formers produced more metabolites than high-biofilm-formers. Further analysis was performed to identify metabolites that differed significantly (p-value < 0.005) between low and high biofilm-formers. These metabolites include major categories of lipids and metabolites involve in prostaglandin and folate metabolism. Our findings suggest that biofilm formation in H. pylori is complex and probably driven by the bacterium' endogenous metabolism. Understanding the underlying metabolic differences between low and high biofilm-formers may enhance our current understanding of pathogenesis, extragastric survival and transmission of H. pylori infections.}, } @article {pmid29360567, year = {2018}, author = {Fu, L and Huang, M and Zhang, X and Yang, X and Liu, Y and Zhang, L and Zhang, Z and Wang, G and Zhou, Y}, title = {Frequency of virulence factors in high biofilm formation blaKPC-2 producing Klebsiella pneumoniae strains from hospitals.}, journal = {Microbial pathogenesis}, volume = {116}, number = {}, pages = {168-172}, doi = {10.1016/j.micpath.2018.01.030}, pmid = {29360567}, issn = {1096-1208}, mesh = {Biofilms/*growth & development ; Carbapenems/pharmacology ; Genotype ; Hospitals ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/*enzymology/genetics/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Polymerase Chain Reaction ; Virulence Factors/*analysis/genetics ; beta-Lactamases/*metabolism ; }, abstract = {The aim of this study is to determine the frequency of virulence genes in high biofilm formation blaKPC-2 producing Klebsiella pneumoniae strains collected over a period of two years. A total of 43 non-repetitive high biofilm blaKPC-2 producing isolates were screened from 429 strains. The MIC of carbapenems (imipenem and meropenem) ranged from 4 to 32 μg/ml. The OD595 value of the biofilm ranged from 0.56 to 2.56. The K1, K2, K5, K20, K54, K57 genotypes, MLST and virulence factors, including entB, ybtS, mrkD, fimH, rmpA, allS, iutA, kfu, wcaG, aerobaction, fecIRA, shiF, magA and pagO gene, were determined by PCR. The results showed that, among the 43 isolates, 5 of 43 were K1 type, 25 of 43 were K2 type, 4 strains and 2 strains were K5 and K57 respectively. The MLST results showed that 23/43 strains were ST11, followed by ST433(4/43), ST107(4/43), ST690(4/43), ST304(2/43), ST2058(1/43), ST1(1/43), ST146(1/43), ST914(1/43), ST2636(1/43), ST2637(1/43). As to the virulence factors, all 43 strains carried entB, ybtS and mrkD gene, followed by fimH(38/43), rmpA(14/43), allS(34/43), iutA(27/43), kfu(25/43), wcaG(21/43), aerobaction(16/43), fecIRA(15/43), shiF(10/43), magA(5/43) and pagO(5/43). This study demonstrated that high frequency of virulence factors emerging in high biofim blaKPC-2 producing strains. It also suggested that we should continue to focus on the toxicity variation and it's high time to enhance clinical awareness to the infections causing by Klebsiella pneumoniae.}, } @article {pmid29358339, year = {2018}, author = {Suriyanarayanan, T and Qingsong, L and Kwang, LT and Mun, LY and Truong, T and Seneviratne, CJ}, title = {Quantitative Proteomics of Strong and Weak Biofilm Formers of Enterococcus faecalis Reveals Novel Regulators of Biofilm Formation.}, journal = {Molecular & cellular proteomics : MCP}, volume = {17}, number = {4}, pages = {643-654}, pmid = {29358339}, issn = {1535-9484}, mesh = {Bacterial Proteins/*metabolism ; *Biofilms ; Enterococcus faecalis/*physiology ; Proteomics ; }, abstract = {Enterococcus faecalis is a bacterial pathogen associated with both endodontic and systemic infections. The biofilm formation ability of E. faecalis plays a key role in its virulence and drug resistance attributes. The formation of E. faecalis biofilms on implanted medical devices often results in treatment failure. In the present study, we report protein markers associated with the biofilm formation ability of E. faecalis using iTRAQ-based quantitative proteomics approach. In order to elucidate the biofilm-associated protein markers, we investigated the proteome of strong and weak biofilm-forming E. faecalis clinical isolates in comparison with standard American Type Culture Collection (ATCC) control strains. Comparison of E. faecalis strong and weak biofilm-forming clinical isolates with ATCC control strains showed that proteins associated with shikimate kinase pathway and sulfate transport were up-regulated in the strong biofilm former, while proteins associated with secondary metabolites, cofactor biosynthesis, and tetrahydrofolate biosynthesis were down-regulated. In the weak biofilm former, proteins associated with nucleoside and nucleotide biosynthesis were up-regulated, whereas proteins associated with sulfate and sugar transport were down-regulated. Further pathway and gene ontology analyses revealed that the major differences in biofilm formation arise from differences in metabolic activity levels of the strong and weak biofilm formers, with higher levels of metabolic activity observed in the weak biofilm former. The differences in metabolic activity could therefore be a major determinant of the biofilm ability of E. faecalis The new markers identified from this study can be further characterized in order to understand their exact role in E. faecalis biofilm formation ability. This, in turn, can lead to numerous therapeutic benefits in the treatment of this oral and systemic pathogen. The data has been deposited to the ProteomeXchange with identifier PXD006542.}, } @article {pmid29357405, year = {2018}, author = {Mao, B and Cheng, L and Wang, S and Zhou, J and Deng, L}, title = {Combat biofilm by bacteriostatic aptamer-functionalized graphene oxide.}, journal = {Biotechnology and applied biochemistry}, volume = {65}, number = {3}, pages = {355-361}, doi = {10.1002/bab.1631}, pmid = {29357405}, issn = {1470-8744}, mesh = {Aptamers, Nucleotide/*pharmacology ; Biofilms/*drug effects ; Graphite/*pharmacology ; Oxides/*pharmacology ; Salmonella typhimurium/*drug effects ; }, abstract = {Biofilms are the main reason for a large number deaths and high health costs. Their better protection compared to planktonic form against conventional antibiotics leads to poor treatment efficiency. Nanoagent-targeted delivery is a promising avenue for disease therapeutic, but its application targeting biofilms has not been reported currently. The roles, if any, of aptamers acting as delivery carrier and targeting factor, the graphene oxide (GO), and GO modified with aptamers against biofilms were then systematically evaluated. Here, we successfully developed an aptamer-targeted GO strategy against biofilms. We investigated the efficacy of aptamer-GO conjugates by UV spectrophotometer, inverted microscopy, and atomic force microscopy; 93.5 ± 3.4% Salmonella typhimurium biofilms were inhibited and 84.6 ± 5.1% of biofilms were dispersed by a ST-3-GO conjugate. More importantly, this conjugate represented distinctively toxicity to S. typhimurium. Thus, this strategy significantly displays excellent antibiofilm properties and may serve as a long-term solution for biofilm control.}, } @article {pmid29356919, year = {2018}, author = {Schmidt, JC and Astasov-Frauenhoffer, M and Waltimo, T and Weiger, R and Walter, C}, title = {Influence of the oscillation frequency of different side-to-side toothbrushes on noncontact biofilm removal.}, journal = {Clinical oral investigations}, volume = {22}, number = {6}, pages = {2141-2147}, pmid = {29356919}, issn = {1436-3771}, mesh = {*Biofilms ; Electricity ; Equipment Design ; Fusobacterium nucleatum ; In Vitro Techniques ; Microscopy, Confocal ; Porphyromonas gingivalis ; Streptococcus sanguis ; Titanium ; Toothbrushing/*instrumentation ; }, abstract = {OBJECTIVES: The objective of this study was to investigate the influence of different oscillation frequencies of three powered toothbrushes with side-to-side action for noncontact biofilm removal in an artificial interdental space model.

MATERIALS AND METHODS: A three-species biofilm (Porphyromonas gingivalis, Fusobacterium nucleatum and Streptococcus sanguinis) was formed in vitro on protein-coated titanium disks using a flow chamber system combined with a static biofilm growth model. The oscillation frequencies of three commercial side-to-side toothbrushes were evaluated by means of a dose response. The frequency was decreased in steps (100, 85, 70, 55, and 40%). Subsequently, the biofilm-coated substrates were exposed to the side-to-side toothbrushes. The biofilm volumes were measured using volumetric analyses (Imaris 8.1.2) with confocal laser scanning microscope images (Zeiss LSM700).

RESULTS: Compared to maximum oscillation frequency (100%), lower oscillation frequencies (up to 40%) resulted in reduced median percentages of biofilm reduction (median biofilm reduction up to 53% for maximum oscillation frequency, and up to 13% for 40% oscillation frequency) (p ≥ 0.03). In addition, decreasing the oscillation frequencies of the side-to-side toothbrushes showed an enhanced variety in the results of repeated experiments.

CONCLUSIONS: The oscillation frequency of the tested side-to-side toothbrushes affected the biofilm reduction in an interdental space model.

CLINICAL RELEVANCE: Within a toothbrush, higher oscillation frequencies may lead to beneficial effects on interdental biofilm removal by noncontact brushing.}, } @article {pmid29356869, year = {2018}, author = {Goel, S and Mishra, P}, title = {Thymoquinone inhibits biofilm formation and has selective antibacterial activity due to ROS generation.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {4}, pages = {1955-1967}, doi = {10.1007/s00253-018-8736-8}, pmid = {29356869}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/*metabolism/toxicity ; Benzoquinones/*metabolism/toxicity ; Biofilms/*drug effects/*growth & development ; Cell Line ; Cell Survival/drug effects ; Gram-Negative Bacteria/*drug effects/physiology/ultrastructure ; Gram-Positive Bacteria/*drug effects/physiology/ultrastructure ; Humans ; Keratinocytes/drug effects/physiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Reactive Oxygen Species/*metabolism ; }, abstract = {The present study was aimed to investigate the antibacterial potential and antibiofilm activity of thymoquinone and its mechanism of action. Antibacterial activity of thymoquinone was studied using minimum inhibitory concentration, minimum bactericidal concentration, time-kill assay, and post-antibiotic effect. Thymoquinone exhibited antibacterial activity against both Gram-negative and Gram-positive bacteria. In this study, the minimum inhibitory concentration was found to be in the range of 1.56 to 100 μg/ml. Scanning electron microscopy imaging revealed changes in cell morphology with dents, cell lysis, and reduction in cell size. Live/dead imaging using acridine orange and ethidium bromide confirmed the bactericidal activity as treated bacteria showed selective uptake of ethidium bromide over acridine orange. Cell viability was also studied using HaCaT (human keratinocytes) cell line by MTT assay, and IC90 value was found to be 50 μg/ml. This IC90 value was higher than that of MICbacteria (except for MIC of E. coli), demonstrating that its selectivity is higher towards bacteria than normal human cells. Thymoquinone also showed promising antibiofilm activity against Gram-negative (E. coli and P. aeruginosa) and Gram-positive bacteria (B. subtilis and S. aureus), which was studied by crystal violet assay, CFU method, and SEM. For understanding the mechanism of action of thymoquinone, DiSC3, NPN, and ROS assay was performed. DiSC3 and NPN assay has not shown any membrane damage whereas bacterial cells treated with thymoquinone at MIC showed increased dichlorofluorescin fluorescence, suggesting that the probable mechanism of action of thymoquinone against bacterial cells is due to the production of reactive oxygen species.}, } @article {pmid29356802, year = {2018}, author = {Luo, J and Wang, K and Li, GS and Lei, DQ and Huang, YJ and Li, WD and Chen, YQ and Kong, JL}, title = {3,5-Dicaffeoylquinic Acid Disperses Aspergillus Fumigatus Biofilm and Enhances Fungicidal Efficacy of Voriconazole and Amphotericin B.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {24}, number = {}, pages = {427-437}, pmid = {29356802}, issn = {1643-3750}, mesh = {Amphotericin B/*pharmacology ; Antifungal Agents/chemistry/*pharmacology ; Aspergillus fumigatus/*drug effects/metabolism/*physiology/ultrastructure ; Biofilms/*drug effects ; Biomass ; Blood Cells/drug effects/metabolism ; Chlorogenic Acid/*analogs & derivatives/chemistry/pharmacology ; Fungal Proteins/genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Hemolysis/drug effects ; Humans ; Microbial Sensitivity Tests ; Polysaccharides/biosynthesis ; Voriconazole/*pharmacology ; }, abstract = {BACKGROUND The aim of this study was to evaluate the dispersal effects of 3,5-dicaffeoylquinic acid (3,5-DCQA) against the preformed biofilm of Aspergillus fumigatus and to investigate its potential mechanism. MATERIAL AND METHODS Aspergillus fumigatus biofilms of laboratory strain AF293 and clinical strain GXMU04 were generated in 24- or 96-well polystyrene microtiter plates in vitro. Crystal violet assay and XTT reduction assay were performed to evaluate the effects of 3,5-DCQA on biofilm biomass, extracellular matrix, and metabolic activity alteration of cells in biofilms. Real-time PCR was performed to quantify the expression of hydrophobin genes. The cytotoxicity of 3,5-DCQA on human erythrocytes was evaluated by a hemolytic assay. RESULTS The results indicated that 3,5-DCQA in subminimum inhibitory concentrations (256 to 1024 mg/L) elicited optimal A. fumigatus biofilm dispersion activity and improved the efficacy of VRC and AMB in minimal fungicidal concentrations (MFCs) to combat fungal cells embedded in biofilms. The results of scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) revealed 3,5-DCQA facilitated the entry of antifungal agents into the A. fumigatus biofilm through eliminating the hydrophobic extracellular matrix (ECM) without affecting fungal growth. Real-time PCR indicated that 3,5-DCQA down-regulated the expression of hydrophobin genes. Hemolytic assay confirmed that 3,5-DCQA exhibited a low cytotoxicity against human erythrocytes. CONCLUSIONS Subminimum inhibitory concentrations of 3,5-DCQA can disperse A. fumigatus biofilm and enhance fungicidal efficacy of VRC and AMB through down-regulating expression of the hydrophobin genes. The study indicated the anti-biofilm potential of 3,5-DCQA for the management of A. fumigatus biofilm-associated infection.}, } @article {pmid29356343, year = {2018}, author = {Suryaletha, K and John, J and Radhakrishnan, MP and George, S and Thomas, S}, title = {Metataxonomic approach to decipher the polymicrobial burden in diabetic foot ulcer and its biofilm mode of infection.}, journal = {International wound journal}, volume = {15}, number = {3}, pages = {473-481}, pmid = {29356343}, issn = {1742-481X}, mesh = {Actinobacteria/isolation & purification ; Aged ; *Biofilms ; Chronic Disease ; Diabetic Foot/*microbiology/pathology ; Enterococcus/isolation & purification ; Female ; Firmicutes/isolation & purification ; Humans ; Male ; Middle Aged ; Proteobacteria/isolation & purification ; Proteus/isolation & purification ; Pseudomonas/isolation & purification ; Staphylococcus/isolation & purification ; Wound Infection/*microbiology/pathology ; }, abstract = {Chronic diabetic foot is a global burden affecting millions of people, and the chronicity of an ulcer is directly linked to the diverse bacterial burden and its biofilm mode of infection. The bacterial diversity of 100 chronic diabetic ulcer samples was profiled via traditional culturing method as well as metagenomic approach by sequencing the 16S rRNA V3 hyper-variable region on Illumina Miseq Platform (Illumina, Inc., San Diego, CA). All the relevant clinical metadata, including duration of diabetes, grade of ulcer, presence of neuropathy, and glycaemic level, were noted and correlated with the microbiota. The occurrence and establishment of bacterial biofilm over chronic wound tissues was revealed by Fluorescent in situ Hybridization and Scanning Electron Microscopy. The biofilm-forming ability of predominant bacterial isolates was studied via crystal violet assay and Confocal Laser Scanning Microscopy. The dominant phyla obtained from bacterial diversity analysis were Firmicutes, Proteobacteria, and Actinobacteria. The dominant aerobic pathogens identified by culture method are Pseudomonas, Proteus, Enterococcus, and Staphylococcus, whereas high-throughput sequencing revealed heightened levels of Streptococcus and Corynebacterium along with 22 different obligate anaerobes. The biofilm occurrence in chronic diabetic ulcer infection is well analysed. Herein, we illustrate the comprehensive pattern of bacterial infection and identify the community composition of chronic wound pathogenic biofilm.}, } @article {pmid29356249, year = {2018}, author = {Rossi, C and Chaves-López, C and Serio, A and Anniballi, F and Valbonetti, L and Paparella, A}, title = {Effect of Origanum vulgare essential oil on biofilm formation and motility capacity of Pseudomonas fluorescens strains isolated from discoloured Mozzarella cheese.}, journal = {Journal of applied microbiology}, volume = {124}, number = {5}, pages = {1220-1231}, doi = {10.1111/jam.13707}, pmid = {29356249}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/isolation & purification/pharmacology ; Biofilms/*drug effects ; Cell Movement/*drug effects ; Cheese/*microbiology ; Oils, Volatile/isolation & purification/*pharmacology ; Origanum/*chemistry ; Pseudomonas fluorescens/drug effects/*isolation & purification ; }, abstract = {AIMS: The study was focused on Pseudomonas fluorescens strains isolated from Mozzarella cheese, with the aim of evaluating the effects of Origanum vulgare L. essential oil (OEO) on the biofilm formation and eradication, as well as on the motility and blue pigment production at 10°C.

METHODS AND RESULTS: Microdilution method was used to determine the minimum inhibitory and bactericidal concentration of the OEO, which ranged between 10 and 40 μl ml[-1] . In vitro studies demonstrated that a sublethal concentration of OEO influenced not only P. fluorescens growth and motility but also the capability to form biofilm and, in a lower degree, the biofilm eradication at 10°C. Analysis by confocal microscopy revealed a dramatic reduction in biofilm formation and thickness, with scattered damage or death of cells, stained by propidium iodide. In addition, a concentration of 5 μl ml[-1] of OEO affected the motility of the cells and, in particular, their ability to swim. However, the essential oil did not inhibit the blue pigment production by any of the tested strains.

CONCLUSIONS: The present findings suggest that oregano essential oil inhibits the biofilm formation of P. fluorescens strains and alters their motility. Moreover, in the preformed biofilm, OEO contributes to the detachment of the cells, deteriorating the architecture of the biofilm and reducing its thickness.

The O. vulgare L. essential oil was revealed as a promising agent against biofilm formation and for its detaching; these results suggest that oregano EO could be used in the dairy food industry to control biofilm formation, as an alternative, or in combination with conventional sanitizers.}, } @article {pmid29355771, year = {2018}, author = {Derakhshan, Z and Mahvi, AH and Ehrampoush, MH and Ghaneian, MT and Yousefinejad, S and Faramarzian, M and Mazloomi, SM and Dehghani, M and Fallahzadeh, H}, title = {Evaluation of kenaf fibers as moving bed biofilm carriers in algal membrane photobioreactor.}, journal = {Ecotoxicology and environmental safety}, volume = {152}, number = {}, pages = {1-7}, doi = {10.1016/j.ecoenv.2018.01.024}, pmid = {29355771}, issn = {1090-2414}, mesh = {Atrazine/*analysis ; Biodegradation, Environmental ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Biomass ; Hibiscus/*chemistry ; Microalgae/*growth & development ; Photobioreactors/*microbiology ; Wastewater/chemistry ; Water Pollutants, Chemical/*analysis ; }, abstract = {In this lab-scale study, the feasibility of using kenaf fibers as moving bed biofilm carriers in hybrid microalgal membrane photobioreactors (HMPBR) in organic matter and atrazine elimination from real secondary effluent was evaluated. For evaluating the kinetics of biofilm substrate consumption, an experimental model was proposed. Inoculation of wastewater samples with free carriers resulted in the greater removal of target pollutants. Removal efficiency of atrazine and chemical oxygen demand (COD) increased to 27% and 16%, with respect to the control, respectively. The total biomass accumulation in HMPBR exceeded 5g/L, and the microalgae tended to aggregate and attached to biofilm carriers. The removal efficiency of HMPBR improved significantly via inoculation of kenaf fiber carriers with bioremediation microalgal strains (p < 0.01). A lower stabilization ratio (VSS/TSS) was also recorded. The biomass in HMPBR included more lipids and carbohydrates. The results revealed that kenaf fibers could improve and upgrade the biological activity of different wastewater treatment applications, considering the great potential of biofilm carriers and their effluent quality.}, } @article {pmid29355421, year = {2018}, author = {Liu, Y and Ren, Z and Hwang, G and Koo, H}, title = {Therapeutic Strategies Targeting Cariogenic Biofilm Microenvironment.}, journal = {Advances in dental research}, volume = {29}, number = {1}, pages = {86-92}, pmid = {29355421}, issn = {1544-0737}, support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025848/DE/NIDCR NIH HHS/United States ; R03 DE025728/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Arginine/pharmacology ; Bacterial Adhesion ; *Biofilms ; Cariostatic Agents/pharmacology ; Cellular Microenvironment/physiology ; Dental Caries/*microbiology/*prevention & control ; Extracellular Matrix/microbiology ; Humans ; Hydrogen-Ion Concentration ; Nanotechnology/trends ; Polysaccharides, Bacterial/physiology ; Streptococcus/pathogenicity ; }, abstract = {Cariogenic biofilms are highly structured microbial communities embedded in an extracellular matrix, a multifunctional scaffold that is essential for the existence of the biofilm lifestyle and full expression of virulence. The extracellular matrix provides the physical and biological properties that enhance biofilm adhesion and cohesion, as well as create a diffusion-modulating milieu, protecting the resident microbes and facilitating the formation of localized acidic pH niches. These biochemical properties pose significant challenges for the development of effective antibiofilm therapeutics to control dental caries. Conventional approaches focusing solely on antimicrobial activity or enhancing remineralization may not achieve maximal efficacy within the complex biofilm microenvironment. Recent approaches disrupting the biofilm microbial community and the microenvironment have emerged, including specific targeting of cariogenic pathogens, modulation of biofilm pH, and synergistic combination of bacterial killing and matrix degradation. Furthermore, new "smart" nanotechnologies that trigger drug release or activation in response to acidic pH are being developed that could enhance the efficacy of current and prospective chemical modalities. Therapeutic strategies that can locally disrupt the pathogenic niche by targeting the biofilm structure and its microenvironment to eliminate the embedded microorganism and facilitate the action of remineralizing agents may lead to enhanced and precise anticaries approaches.}, } @article {pmid29353420, year = {2018}, author = {Jałowiecki, Ł and Żur, J and Chojniak, J and Ejhed, H and Płaza, G}, title = {Properties of Antibiotic-Resistant Bacteria Isolated from Onsite Wastewater Treatment Plant in Relation to Biofilm Formation.}, journal = {Current microbiology}, volume = {75}, number = {5}, pages = {639-649}, pmid = {29353420}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/classification/*drug effects/*isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; Wastewater/*microbiology ; Water Purification/*instrumentation ; }, abstract = {The aim of the present study was to determine some properties of antibiotic-resistant bacterial strains isolated from onsite wastewater technology in relation to biofilm formation, e.g., autoaggregation and motility. Additionally, biosurfactant production by the isolates was also evaluated. The ability of selected strains to develop a biofilm was assessed by using the crystal violet method, which allows to indirectly quantify the attached bacterial biomass (live, dead cells, and polysaccharides as well). Obtained results showed that 19 of the analyzed strains were able to produce biofilm after 72 h of incubation. The low values of surface tension in the range between 28 and 36 mN/m were observed in the bacteria, which are not able to produce biofilm or be classified as weak biofilm producers. Among biofilm-forming strains the highest autoaggregation index was observed for Mycobacterium brumae and Bacillus alcalophilus. Noteworthy, that some strains capable of biofilm formation showed no aggregation abilities or were characterized by low autoaggregative properties. The results of visual autoaggregation assay showed no visible flocs after given time of incubation. The results from motility test demonstrated that most of the analyzed strains were motile. Noteworthy, that up to now literature data about physiology, biofilm formation, and autoaggregative capabilities of bacteria isolated from onsite wastewater technology are very limited and this paper gives the information on the antibiotic-resistant bacteria with ability to form biofilm. Thus, the present study points to develop novel bioinocula in antibiotic degradation and to reach novel biofilm-dispersing agents produced by various bacteria that can be used as disinfectants or surface-coating agents to prevent microbial surface colonization and biofilm development.}, } @article {pmid29353377, year = {2018}, author = {Bardbari, AM and Arabestani, MR and Karami, M and Keramat, F and Aghazadeh, H and Alikhani, MY and Bagheri, KP}, title = {Highly synergistic activity of melittin with imipenem and colistin in biofilm inhibition against multidrug-resistant strong biofilm producer strains of Acinetobacter baumannii.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {37}, number = {3}, pages = {443-454}, pmid = {29353377}, issn = {1435-4373}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colistin/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Humans ; Imipenem/*pharmacology ; Kinetics ; Melitten/*pharmacology ; Microbial Sensitivity Tests ; }, abstract = {The rapid increase of drug resistance and failure of available antibiotics to treat biofilm-associated infections is of great health concern. Accordingly, our study aimed to evaluate the synergistic antibacterial, biofilm inhibitory, and biofilm removal activities of melittin in combination with colistin, imipenem, and ciprofloxacin against multidrug-resistant (MDR) strong biofilm producer Acinetobacter baumannii isolates. The kinetics of biofilm formation were evaluated for the isolates for 144 h. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities for melittin and combinations with antibiotics were determined. Inhibition of biofilm-associated protein (bap) expression by melittin was evaluated with real-time polymerase chain reaction (PCR). Field emission scanning electron microscopy (FE-SEM) was used to visualize the effect of synergism on the inhibition of biofilm production. The geometric means of the fractional inhibitory concentration index (FICi) for melittin-colistin, melittin-imipenem, and melittin-ciprofloxacin combinations were calculated as 0.31, 0.24, and 0.94, respectively. Comparing the geometric means of the removal activity for melittin, colistin, imipenem, and combinations of them in both 6 and 24 h showed a significant difference between the groups (p-value < 0.05). Exposure to melittin induced a statistically significant downregulation of bap mRNA levels in all isolates at sub-MIC doses. Analysis of the FE-SEM results demonstrated that the synergism of melittin-colistin at 0.125-0.25 μg inhibited biofilm formation completely. In conclusion, our findings indicate that melittin possesses considerable potential for use in combination with colistin and imipenem to treat infections caused by MDR strong biofilm producer A. baumannii isolates.}, } @article {pmid29352435, year = {2018}, author = {Akgün, D and Perka, C and Trampuz, A and Renz, N}, title = {Outcome of hip and knee periprosthetic joint infections caused by pathogens resistant to biofilm-active antibiotics: results from a prospective cohort study.}, journal = {Archives of orthopaedic and trauma surgery}, volume = {138}, number = {5}, pages = {635-642}, doi = {10.1007/s00402-018-2886-0}, pmid = {29352435}, issn = {1434-3916}, mesh = {Anti-Bacterial Agents/pharmacology ; Arthroplasty, Replacement, Hip/adverse effects/statistics & numerical data ; Arthroplasty, Replacement, Knee/adverse effects/statistics & numerical data ; Biofilms ; Child, Preschool ; *Drug Resistance, Bacterial ; Hip Joint/surgery ; Humans ; Kaplan-Meier Estimate ; Knee Joint/surgery ; Prospective Studies ; *Prosthesis-Related Infections/epidemiology/microbiology/mortality ; }, abstract = {BACKGROUND: Periprosthetic joint infections (PJI) caused by pathogens, for which no biofilm-active antibiotics are available, are often referred to as difficult-to-treat (DTT). However, it is unclear whether the outcome of DTT PJI is worse than those of non-DTT PJI. We evaluated the outcome of DTT and non-DTT PJI in a prospective cohort treated with a two-stage exchange according to a standardized algorithm.

METHODS: Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed up for ≥ 2 years. DTT PJI was defined as growth of microorganism(s) resistant to all available biofilm-active antibiotics. The Kaplan-Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI and the 95% confidence interval (95% CI) was calculated.

RESULTS: Among 163 PJI, 30 (18.4%) were classified as DTT and 133 (81.6%) as non-DTT. At a mean follow-up of 33 months (range 24-48 months), the overall treatment success was 82.8%. The infection-free survival rate at 2 years was 80% (95% CI 61-90%) for DTT PJI and 84% (95% CI 76-89%) for non-DTT PJI (p = 0.61). The following mean values were longer in DTT PJI than in non-DTT PJI: hospital stay (45 vs. 28 days; p < 0.001), prosthesis-free interval (89 vs. 58 days; p < 0.001) and duration of antimicrobial treatment (151 vs. 117 days; p = 0.003).

CONCLUSIONS: The outcome of DTT and non-DTT PJI was similar (80-84%), however, at the cost of longer hospital stay, longer prosthesis-free interval and longer antimicrobial treatment. It remains unclear whether patients undergoing two-stage exchange with a long interval need biofilm-active antibiotics. Further studies need to evaluate the outcome in patients treated with biofilm-active antibiotics undergoing short vs. long interval.}, } @article {pmid29352409, year = {2018}, author = {Skariyachan, S and Sridhar, VS and Packirisamy, S and Kumargowda, ST and Challapilli, SB}, title = {Recent perspectives on the molecular basis of biofilm formation by Pseudomonas aeruginosa and approaches for treatment and biofilm dispersal.}, journal = {Folia microbiologica}, volume = {63}, number = {4}, pages = {413-432}, pmid = {29352409}, issn = {1874-9356}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Gene Expression Regulation, Bacterial ; Humans ; Models, Biological ; Polysaccharides, Bacterial/chemistry ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development/*physiology ; Quorum Sensing ; }, abstract = {Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.}, } @article {pmid29352081, year = {2018}, author = {Hall, CW and Hinz, AJ and Gagnon, LB and Zhang, L and Nadeau, JP and Copeland, S and Saha, B and Mah, TF}, title = {Pseudomonas aeruginosa Biofilm Antibiotic Resistance Gene ndvB Expression Requires the RpoS Stationary-Phase Sigma Factor.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {7}, pages = {}, pmid = {29352081}, issn = {1098-5336}, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Drug Resistance, Microbial/*genetics ; *Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/genetics/*physiology ; Sigma Factor/*genetics/metabolism ; }, abstract = {Chronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogen Pseudomonas aeruginosa, biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential-phase planktonic cells. One such mechanism involves ndvB, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable green fluorescent protein (GFP) transcriptional reporter to observe the expression pattern of ndvB We found that in addition to its expression in biofilms, ndvB was upregulated in planktonic cells as they enter stationary phase. The transcription of ndvB in both growth phases was shown to be dependent on the stationary-phase sigma factor RpoS, and mutation of a putative RpoS binding site in the ndvB promoter abolished the activity of the promoter in stationary-phase cells. Overall, we have expanded our understanding of the temporal expression of ndvB in P. aeruginosa and have uncovered a regulatory basis for its growth phase-dependent expression.IMPORTANCE Bacterial biofilms are more resistant to antibiotics than free-living planktonic cells, and understanding the mechanistic basis of this resistance can inform treatments of biofilm-based infections. In addition to chemical and structural barriers that can inhibit antibiotic entry, the upregulation of specific genes in biofilms contributes to the resistance. We investigated this biofilm-specific gene induction by examining expression patterns of ndvB, a gene involved in biofilm resistance of the opportunistic pathogen Pseudomonas aeruginosa We characterized ndvB expression in planktonic and biofilm growth conditions with an unstable green fluorescent protein (GFP) reporter and found that the expression of ndvB in biofilms is dependent on the stationary-phase sigma factor RpoS. Overall, our results support the physiological similarity between biofilms and stationary-phase cells and suggest that the induction of some stationary-phase genes in biofilms may contribute to their increased antibiotic resistance.}, } @article {pmid29351199, year = {2018}, author = {Notcovich, S and DeNicolo, G and Flint, SH and Williamson, NB and Gedye, K and Grinberg, A and Lopez-Villalobos, N}, title = {Biofilm-Forming Potential of Staphylococcus aureus Isolated from Clinical Mastitis Cases in New Zealand.}, journal = {Veterinary sciences}, volume = {5}, number = {1}, pages = {}, pmid = {29351199}, issn = {2306-7381}, abstract = {Biofilm formation is of growing concern in human and animal health. However, it is still unclear how biofilms are related to mastitis infections in dairy cattle. In this study, a comparison between two tests for biofilm formation and the association between biofilm and the presence of genes associated with biofilm formation were investigated for 92 Staphylococcus aureus isolates from clinical mastitis cases. Congo red agar (CRA) and microtitre test assay (MTA) in vitro phenotypic tests were used to evaluate biofilm formation. The presence of icaA, icaD, and bap genes associated with biofilm formation was confirmed using the polymerase chain reaction. Results show that most of the S. aureus isolates, though not possessing one of the biofilm-forming genes, were able to produce biofilms. MTA was more frequently positive in identifying biofilm-forming isolates than CRA.}, } @article {pmid29348589, year = {2018}, author = {Joshi, S and Mumtaz, S and Singh, J and Pasha, S and Mukhopadhyay, K}, title = {Novel Miniature Membrane Active Lipopeptidomimetics against Planktonic and Biofilm Embedded Methicillin-Resistant Staphylococcus aureus.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {1021}, pmid = {29348589}, issn = {2045-2322}, mesh = {Animals ; Antimicrobial Cationic Peptides/chemical synthesis/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biomimetics ; Cell Survival/drug effects ; Chemistry Techniques, Synthetic ; Drug Design ; Lipopeptides/chemical synthesis/isolation & purification/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/ultrastructure ; Mice ; Microbial Sensitivity Tests ; Plankton/*drug effects ; Time Factors ; }, abstract = {Escalating multidrug resistance and highly evolved virulence mechanisms have aggravated the clinical menace of methicillin-resistant Staphylococcus aureus (MRSA) infections. Towards development of economically viable staphylocidal agents here we report eight structurally novel tryptophan-arginine template based peptidomimetics. Out of the designed molecules, three lipopeptidomimetics (S-6, S-7 and S-8) containing 12-amino dodecanoic acid exhibited cell selectivity and good to potent activity against clinically relevant pathogens MRSA, methicillin-resistant Staphylococcus epidermidis and vancomycin-resistant Enterococcus faecium (MIC: 1.4-22.7 μg/mL). Mechanistically, the active peptidomimetics dissipated membrane potential and caused massive permeabilization on MRSA concomitant with loss of viability. Against stationary phase MRSA under nutrient-depleted conditions, active peptidomimetics S-7 and S-8 achieved > 6 log reduction in viability upon 24 h incubation while both S-7 (at 226 μg/mL) and S-8 (at 28 μg/mL) also destroyed 48 h mature MRSA biofilm causing significant decrease in viability (p < 0.05). Encouragingly, most active peptidomimetic S-8 maintained efficacy against MRSA in presence of serum/plasma while exhibiting no increase in MIC over 17 serial passages at sub-MIC concentrations implying resistance development to be less likely. Therefore, we envisage that the current template warrants further optimization towards the development of cell selective peptidomimetics for the treatment of device associated MRSA infections.}, } @article {pmid29348586, year = {2018}, author = {Danquah, CA and Kakagianni, E and Khondkar, P and Maitra, A and Rahman, M and Evangelopoulos, D and McHugh, TD and Stapleton, P and Malkinson, J and Bhakta, S and Gibbons, S}, title = {Analogues of Disulfides from Allium stipitatum Demonstrate Potent Anti-tubercular Activities through Drug Efflux Pump and Biofilm Inhibition.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {1150}, pmid = {29348586}, issn = {2045-2322}, support = {G0801956/MRC_/Medical Research Council/United Kingdom ; G0802079/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Allium/*chemistry ; Antitubercular Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Disulfides/chemistry/isolation & purification/*pharmacology ; Escherichia coli/drug effects/growth & development ; Genes, MDR/*drug effects ; Klebsiella/drug effects/growth & development ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis/*drug effects/growth & development ; Plant Extracts/chemistry ; Proteus/drug effects/growth & development ; Staphylococcus aureus/drug effects/growth & development ; }, abstract = {Disulfides from Allium stipitatum, commonly known as Persian shallot, were previously reported to possess antibacterial properties. Analogues of these compounds, produced by S-methylthiolation of appropriate thiols using S-methyl methanethiosulfonate, exhibited antimicrobial activity, with one compound inhibiting the growth of Mycobacterium tuberculosis at 17 µM (4 mg L[-1]) and other compounds inhibiting Escherichia coli and multi-drug-resistant (MDR) Staphylococcus aureus at concentrations ranging between 32-138 µM (8-32 mg L[-1]). These compounds also displayed moderate inhibitory effects on Klebsiella and Proteus species. Whole-cell phenotypic bioassays such as the spot-culture growth inhibition assay (SPOTi), drug efflux inhibition, biofilm inhibition and cytotoxicity assays were used to evaluate these compounds. Of particular note was their ability to inhibit mycobacterial drug efflux and biofilm formation, while maintaining a high selectivity towards M. tuberculosis H37Rv. These results suggest that methyl disulfides are novel scaffolds which could lead to the development of new drugs against tuberculosis (TB).}, } @article {pmid29348582, year = {2018}, author = {Cao, Y and Su, B and Chinnaraj, S and Jana, S and Bowen, L and Charlton, S and Duan, P and Jakubovics, NS and Chen, J}, title = {Nanostructured titanium surfaces exhibit recalcitrance towards Staphylococcus epidermidis biofilm formation.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {1071}, pmid = {29348582}, issn = {2045-2322}, support = {MR/N010345/1//Medical Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/chemistry ; Bacterial Adhesion ; Biofilms/*growth & development ; Cell Membrane/ultrastructure ; Microbial Viability ; Nanostructures/*chemistry/*microbiology/ultrastructure ; Staphylococcus epidermidis/*physiology ; Surface Properties ; Titanium/*chemistry ; }, abstract = {Titanium-based implants are ubiquitous in the healthcare industries and often suffer from bacterial attachment which results in infections. An innovative method of reducing bacterial growth is to employ nanostructures on implant materials that cause contact-dependent cell death by mechanical rupture of bacterial cell membranes. To achieve this, we synthesized nanostructures with different architectures on titanium surfaces using hydrothermal treatment processes and then examined the growth of Staphylococcus epidermidis on these surfaces. The structure obtained after a two-hour hydrothermal treatment (referred to as spear-type) showed the least bacterial attachment at short times but over a period of 6 days tended to support the formation of thick biofilms. By contrast, the structure obtained after a three-hour hydrothermal treatment (referred to as pocket-type) was found to delay biofilm formation up to 6 days and killed 47% of the initially attached bacteria by penetrating or compressing the bacteria in between the network of intertwined nano-spears. The results point to the efficacy of pocket-type nanostructure in increasing the killing rate of individual bacteria and potentially delaying longer-term biofilm formation.}, } @article {pmid29348094, year = {2018}, author = {Hannan, A and Bajwa, AE and Riaz, S and Arshad, U and Saleem, S and Bajwa, UI}, title = {In vitro Salmonella typhi biofilm formation on gallstones and its disruption by Manuka honey.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {31}, number = {1}, pages = {129-135}, pmid = {29348094}, issn = {1011-601X}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Gallstones/*microbiology ; *Honey ; Humans ; In Vitro Techniques ; Leptospermum ; Microbial Sensitivity Tests ; Salmonella typhi/*drug effects/growth & development ; Time Factors ; }, abstract = {Biofilm is a complex community of single or different types of microorganisms (bacteria, viruses, fungi, protozoa) attached to a surface and stick to each other through production of extracellular matrix. Salmonella typhi forms biofilm on cholesterol gallstones resulting in carrier state. Once formed, biofilm is difficult to treat. To date cholecystectomy is the only cure for this condition. Manuka honey is known to have tremendous antibiofilm activity against various organisms. S. typhi biofilm was grown in vitro on clinical samples of human cholesterol gallstones by Gallstone tube assay method for 12 days. Biofilm mass was quantified on day 1, 5, 7, 9 and 12 by crystal violet assay and was also examined by scanning electron microscope. Three concentrations w/v of Manuka honey (40%, 60% and 80%) were used, each one at 24, 48 and 72 hours. The most effective concentration (80% w/v) was repeated on two sets of gallstones. Biofilm mass was re quantified by crystal violet assay and was examined by scanning electron microscope. S. typhi formed uniform biofilm on cholesterol gallstone surface. The optical density measurements exhibited a rising pattern with time thereby indicating an increase in biofilm mass. It was 0.2 on day 1 and 0.9 on day 12. With 80% w/v Manuka honey, biofilm mass decreased most effectively with 0.5 OD after 72 hours. Biofilm formation by S, typhi on gallstones is surface specific and bile dependant. Either increasing the duration (beyond 72 hours) of the effective concentration (80% w/v) of honey or increasing the concentration (above 80%) of honey for a specific duration (72 hour) may cause complete disruption of the S. typhi biofilm on gallstone. S. typhi forms biofilm on cholesterol gallstones surface in vitro and it can be visualized by scanning electron microscopy. Biofilm mass can be quantified using crystal violet assay. Among various concentrations 80% Manuka honey for 72 hours is most effective in disrupting S. typhi biofilm on gallstones in vitro as evident from crystal violet assay.}, } @article {pmid29347829, year = {2018}, author = {Hunsucker, KZ and Vora, GJ and Hunsucker, JT and Gardner, H and Leary, DH and Kim, S and Lin, B and Swain, G}, title = {Biofilm community structure and the associated drag penalties of a groomed fouling release ship hull coating.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {162-172}, doi = {10.1080/08927014.2017.1417395}, pmid = {29347829}, issn = {1029-2454}, mesh = {Biofilms/growth & development ; Biofouling/*prevention & control ; Diatoms/*growth & development ; *Friction ; *Ships ; Surface Properties ; }, abstract = {Grooming is a proactive method to keep a ship's hull free of fouling. This approach uses a frequent and gentle wiping of the hull surface to prevent the recruitment of fouling organisms. A study was designed to compare the community composition and the drag associated with biofilms formed on a groomed and ungroomed fouling release coating. The groomed biofilms were dominated by members of the Gammaproteobacteria and Alphaproteobacteria as well the diatoms Navicula, Gomphonemopsis, Cocconeis, and Amphora. Ungroomed biofilms were characterized by Phyllobacteriaceae, Xenococcaceae, Rhodobacteraceae, and the pennate diatoms Cyclophora, Cocconeis, and Amphora. The drag forces associated with a groomed biofilm (0.75 ± 0.09 N) were significantly less than the ungroomed biofilm (1.09 ± 0.06 N). Knowledge gained from this study has helped the design of additional testing which will improve grooming tool design, minimizing the growth of biofilms and thus lowering the frictional drag forces associated with groomed surfaces.}, } @article {pmid29346603, year = {2018}, author = {Obe, T and Nannapaneni, R and Sharma, CS and Kiess, A}, title = {Homologous stress adaptation, antibiotic resistance, and biofilm forming ability of Salmonella enterica serovar Heidelberg ATCC8326 on different food-contact surfaces following exposure to sublethal chlorine concentrations1.}, journal = {Poultry science}, volume = {97}, number = {3}, pages = {951-961}, doi = {10.3382/ps/pex346}, pmid = {29346603}, issn = {1525-3171}, mesh = {Adaptation, Physiological/drug effects ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Dose-Response Relationship, Drug ; *Food Handling ; *Food Microbiology ; Microbial Sensitivity Tests ; Plastics ; Salmonella enterica/*drug effects/*physiology ; Sodium Hypochlorite/*pharmacology ; Stainless Steel ; Stress, Physiological/drug effects ; }, abstract = {Salmonella enterica serovar Heidelberg (American Type Culture Collection; ATCC 8326) was examined for the ability to adapt to the homologous stress of chlorine through exposure to increasing chlorine concentrations (25 ppm daily increments) in tryptic soy broth (TSB). The tested strain exhibited an acquired tolerance to chlorine in TSB with the tolerant cells growing in concentrations up to 400 ppm. In addition, the chlorine stressed cells displayed rugose morphology on tryptic soy agar (TSA) plates at 37°C. The minimum inhibitory concentration (MIC) of chlorine for adapted (rugose and smooth) cells was determined to be 550 ppm and 500 ppm, respectively whereas the MIC for the control was 450 ppm. The biofilm forming ability of the adapted and control cells were examined on both plastic and stainless steel surface at room temperature and 37°C. The rugose variant, in contrast to the smooth (adapted and control) showed the ability to form strong biofilms (P ≤ 0.05) on a plastic surface at room temperature and 37°C. Rugose cells compared to smooth and control attached more (P ≤ 0.05) to steel surfaces as well. The possibility of cross-adaptation was examined by exposing the adapted and control cells to different antibiotics according to the Clinical & Laboratory Standards Institute guidelines. Adapted cells exhibited reduced susceptibility to some of the antibiotics tested as compared to control. The findings of this study suggest that exposure to sublethal chlorine concentration during the sanitization procedure can result in tolerant Salmonella cells. Chlorine may confer cross-protection that aids in the survival of the tolerant population to other environmental stresses.}, } @article {pmid29346268, year = {2018}, author = {Raie, DS and Mhatre, E and El-Desouki, DS and Labena, A and El-Ghannam, G and Farahat, LA and Youssef, T and Fritzsche, W and Kovács, ÁT}, title = {Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development.}, journal = {Materials (Basel, Switzerland)}, volume = {11}, number = {1}, pages = {}, pmid = {29346268}, issn = {1996-1944}, abstract = {The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed by heat treatment. Successfully, quercetin was immobilized on the nanocomposite via physical adsorption to form a quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite. The adhesion of bacteria on the coated-slides was verified after 24 h using confocal laser-scanning microscopy. Results indicated that the quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite had more negativity and higher recovery by glass surfaces than its counterpart. Moreover, coating surfaces with the quercetin-modified nanocomposite lowered both hydrophilicity and surface-attached bacteria compared to surfaces coated with the multi-walled carbon nanotubes/titanium dioxide nanocomposite.}, } @article {pmid29345453, year = {2018}, author = {Lockhart, JN and Spoonmore, TJ and McCurdy, MW and Rogers, BR and Guelcher, SA and Harth, E}, title = {Poly(glycidol) Coating on Ultrahigh Molecular Weight Polyethylene for Reduced Biofilm Growth.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {4}, pages = {4050-4056}, pmid = {29345453}, issn = {1944-8252}, support = {R01 AR064772/AR/NIAMS NIH HHS/United States ; P60 DK020593/DK/NIDDK NIH HHS/United States ; P30 DK058404/DK/NIDDK NIH HHS/United States ; P30 HD015052/HD/NICHD NIH HHS/United States ; P30 DK020593/DK/NIDDK NIH HHS/United States ; P30 CA068485/CA/NCI NIH HHS/United States ; }, mesh = {Biofilms ; Coated Materials, Biocompatible ; Molecular Weight ; Polyethylenes ; Propylene Glycols/*chemistry ; Staphylococcus aureus ; }, abstract = {Semibranched poly(glycidol) (PG-OH) and poly(glycidol allylglycidyl ether) (PG-Allyl) coatings were formed on ultrahigh molecular weight polyethylene (UMWPE) in a unique two-step process which included radiation of UHMWPE followed by grafting of PG-OH or PG-Allyl to the surface via free radical cross-linking. Resulting surfaces were extensively characterized by FTIR-ATR, XPS, fluorescent microscopy, and contact goniometry. The performance was evaluated using the most prominent biofilm-forming bacteria Staphylococcus aureus for 24 and 48 h. The PG-Allyl coating demonstrated a 3 log reduction in biofilm growth compared to noncoated control, demonstrating a promising potential to inhibit adherence and colonization of biofilm-forming bacteria that often develop into persistent infections.}, } @article {pmid29343818, year = {2018}, author = {Das Ghatak, P and Mathew-Steiner, SS and Pandey, P and Roy, S and Sen, CK}, title = {A surfactant polymer dressing potentiates antimicrobial efficacy in biofilm disruption.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {873}, pmid = {29343818}, issn = {2045-2322}, support = {R01 DK076566/DK/NIDDK NIH HHS/United States ; R01 NR015676/NR/NINR NIH HHS/United States ; R01 GM108014/GM/NIGMS NIH HHS/United States ; R01 NR013898/NR/NINR NIH HHS/United States ; P30 CA016058/CA/NCI NIH HHS/United States ; R01 GM077185/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Bacteria/drug effects/growth & development ; Biofilms/*drug effects/growth & development ; *Biological Dressings ; Humans ; Polymers/*chemistry ; Surface-Active Agents/*chemistry ; Virulence Factors ; Wound Healing ; Wound Infection/drug therapy/microbiology ; }, abstract = {A 100% water-soluble surfactant polymer dressing (SPD) that is bio-compatible and non-ionic has been reported to improve wound closure in preliminary clinical studies. The mechanism of action of SPD in wound healing remains unclear. Biofilm infection is a significant problem that hinders proper wound closure. The objective of this study was to characterize the mechanism of action of SPD inhibition of bacterial biofilm development. Static biofilms (48 h) of the primary wound pathogens Pseudomonas aeruginosa (PA01), Staphylococcus aureus (USA300) were grown on polycarbonate membranes and treated with SPD with and without antibiotics for an additional 24 h. The standard antibiotics - tobramycin (10 μg/ml) for PA01 and rifampicin (10 μg/ml) for USA300, were used in these studies. Following 24 h treatment with and without antibiotics, the biofilms were characterized using scanning electron microscopy (SEM) structural imaging, in vitro imaging system (IVIS) proliferation imaging, colony forming units (CFU), viability assay, quantitative PCR (qPCR) for virulence gene expression. Because SPD is a surfactant based dressing, it potentially has a direct effect on Gram negative bacteria such as Pseudomonas primarily due to the lipid-based outer membrane of the bacteria. SPD is a surfactant based dressing that has potent anti-biofilm properties directly or in synergy with antibiotics.}, } @article {pmid29342260, year = {2018}, author = {Alves, PM and Al-Badi, E and Withycombe, C and Jones, PM and Purdy, KJ and Maddocks, SE}, title = {Interaction between Staphylococcus aureus and Pseudomonas aeruginosa is beneficial for colonisation and pathogenicity in a mixed biofilm.}, journal = {Pathogens and disease}, volume = {76}, number = {1}, pages = {}, doi = {10.1093/femspd/fty003}, pmid = {29342260}, issn = {2049-632X}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Cell Line ; Coinfection/microbiology/pathology ; Cytokines/metabolism ; Enzyme-Linked Immunosorbent Assay ; Humans ; Keratinocytes/immunology/microbiology ; *Microbial Interactions ; Models, Biological ; Pseudomonas Infections/microbiology/pathology ; Pseudomonas aeruginosa/*growth & development/physiology ; Staphylococcal Infections/microbiology/pathology ; Staphylococcus aureus/*growth & development/physiology ; }, abstract = {Debate regarding the co-existence of Staphylococcus aureus and Pseudomonas aeruginosa in wounds remains contentious, with the dominant hypothesis describing a situation akin to niche partitioning, whereby both microorganisms are present but occupy distinct regions of the wound without interacting. In contrast, we hypothesised that these microorganisms do interact during early co-colonisation in a manner beneficial to both bacteria. We assessed competitive interaction between S. aureus and P. aeruginosa in biofilm cultured for 24-72 h and bacterial aggregates analogous to those observed in early (<24 h) biofilm formation, and interaction with human keratinocytes. We observed that S. aureus predominated in biofilm and non-attached bacterial aggregates, acting as a pioneer for the attachment of P. aeruginosa. We report for the first time that S. aureus mediates a significant (P < 0.05) increase in the attachment of P. aeruginosa to human keratinocytes, and that P. aeruginosa promotes an invasive phenotype in S. aureus. We show that co-infected keratinocytes exhibit an intermediate inflammatory response concurrent with impaired wound closure that is in keeping with a sustained proinflammatory response which allows for persistent microbial colonisation. These studies demonstrate that, contrary to the dominant hypothesis, interactions between S. aureus and P. aeruginosa may be an important factor for both colonisation and pathogenicity in the chronic infected wound.}, } @article {pmid29341381, year = {2018}, author = {Duarte, PHM and da Silva, PB and Rosa, RAD and Montagner, F and Duarte, MAH and Kuga, MC and Só, MVR}, title = {Effect of ethanol on the antimicrobial properties of chlorhexidine over oral biofilm.}, journal = {Microscopy research and technique}, volume = {81}, number = {4}, pages = {408-412}, doi = {10.1002/jemt.22992}, pmid = {29341381}, issn = {1097-0029}, mesh = {Adult ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cattle ; Chlorhexidine/*pharmacology ; Dentin/microbiology/ultrastructure ; Enterococcus faecalis/drug effects/physiology ; Ethanol/*analysis ; Female ; Humans ; Male ; Microscopy, Confocal ; Peritoneal Lavage/instrumentation/methods ; Root Canal Irrigants/*pharmacology ; Young Adult ; }, abstract = {The aim of this study was to evaluate the effect of 95% ethanol irrigation, with 5 or 10 min of action, on the antibacterial properties of 2% chlorhexidine (CHX), on oral biofilm, evaluated with confocal laser scanning microscopy (CLSM). Oral biofilm development was induced in 80 sterilized bovine dentin blocks, distributed in two groups (5 or 10 min) and 4 subgroups, according to time and the solution used: Saline (SALINE5, SALINE10); Saline followed by CHX (SALINE/CHX5, SALINE/CHX10); Ethanol (ETHANOL5, ETHANOL10), Ethanol followed by CHX (ETHANOL/CHX5, ETHANOL/CHX10). The surface of the block was dyed with Live/Dead[®] BacLight. Images from different areas were analyzed by BioImage L program. The total biovolum (µm[3]), biovolum of live cells (green), percentage of live cells of the thickness of the biofilm visualized in CLSM and on surface biofilm were evaluated. Total biovolum and biovolum of living cells showed similar results among the different groups (p > .05). The percentage of living cells in total thickness of the biofilm also was similar among the groups (p > .05), except ETHANOL5, SALINE/CHX10, ETHANOL10, and ETHANOL/CHX10 that showed lower percentage than SALINE5 (p < .05). The ETHANOL10 and ETHANOL/CHX10 also showed lower percentage of living cells than ETHANOL/CHX5 and SALINE10 (p < .05). In relation to biofilm surface, SALINE/CHX5, SALINE/CHX10, ETHANOL5, ETHANOL10, ETHANOL/CHX5, and ETHANOL/CHX10 showed a lower percentage of living cells percentage than SALINE5 and SALINE10 groups (p < .05). Therefore, ethanol has no effect on antimicrobial properties of 2% chlorhexidine, prior when used as endodontic irrigating solution.}, } @article {pmid29341217, year = {2018}, author = {Horne, SM and Schroeder, M and Murphy, J and Prüβ, BM}, title = {Acetoacetate and ethyl acetoacetate as novel inhibitors of bacterial biofilm.}, journal = {Letters in applied microbiology}, volume = {66}, number = {4}, pages = {329-339}, doi = {10.1111/lam.12852}, pmid = {29341217}, issn = {1472-765X}, mesh = {Acetoacetates/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cronobacter sakazakii/*growth & development/isolation & purification ; DNA-Binding Proteins/genetics ; Escherichia coli O157/*growth & development/isolation & purification ; Gene Expression/drug effects ; Humans ; Operon ; Plasmids ; Serratia marcescens/*growth & development/isolation & purification ; Virulence/genetics ; Yersinia enterocolitica/*growth & development/isolation & purification/pathogenicity ; }, abstract = {UNLABELLED: Acetoacetate (AAA) was identified as a biofilm inhibitor in a previous study, where the effect of 190 carbon and nitrogen sources on biofilm amounts by Escherichia coli O157:H7 was determined. With this study, we tested the effect of AAA on growth and biofilm amounts of Cronobacter sakazakii, Serratia marcescens and Yersinia enterocolitica. AAA reduced growth and biofilm amounts of the three pathogens, albeit at rather high concentrations of 10 to 35 mg ml[-1] . Acetoacetate at a concentration of 5 mg ml[-1] reduced Y. enterocolitica mRNA transcripts of the flagellar master regulator operon flhD, the invasion gene inv, and the adhesion gene yadA. Transcription of the regulator of plasmid-encoded virulence genes virF, the plasmid-encoded virulence gene yopQ, and ymoA were largely unaffected by AAA. Importantly, AAA did not cause an increase in transcription of any of the tested virulence genes. As a more cost efficient homologue of AAA, the effect of ethyl acetoacetate (EAA) was tested. EAA reduced growth, biofilm amounts and live bacterial cell counts up to 3 logs. IC50 values ranged from 0·31 mg ml[-1] to 5·6 mg ml[-1] . In summary, both AAA and EAA inhibit biofilm, but EAA appears to be more effective.

Bacterial biofilms are communities of bacteria that form on surfaces and are extremely difficult to remove by conventional physical or chemical techniques, antibiotics or the human immune system. Despite advanced technologies, biofilm still contributes to 60 to 80% of human bacterial infections (NIH and CDC) and cause problems in many natural, environmental, bioindustrial or food processing settings. The discovery of novel substances that inhibit biofilm without increasing the virulence of the bacteria opens doors for countless applications where a reduction of biofilm is desired.}, } @article {pmid29339624, year = {2018}, author = {Manu, DS and Kumar Thalla, A}, title = {The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic-anoxic-oxic activated sludge biofilm reactor.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {77}, number = {1-2}, pages = {248-259}, doi = {10.2166/wst.2017.537}, pmid = {29339624}, issn = {0273-1223}, mesh = {Anaerobiosis ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Biomass ; Bioreactors/*microbiology ; Carbon/*analysis ; Hydrodynamics ; Nitrogen/*analysis ; Oxygen/*chemistry ; Phosphorus/analysis ; Sewage/*chemistry ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; }, abstract = {The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic-anoxic-oxic activated sludge biofilm (A[2]O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A[2]O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4[+]-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 μm. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides.}, } @article {pmid29339459, year = {2018}, author = {Camargo, TM and Stipp, RN and Alves, LA and Harth-Chu, EN and Höfling, JF and Mattos-Graner, RO}, title = {Novel Two-Component System of Streptococcus sanguinis Affecting Functions Associated with Viability in Saliva and Biofilm Formation.}, journal = {Infection and immunity}, volume = {86}, number = {4}, pages = {}, pmid = {29339459}, issn = {1098-5522}, mesh = {Bacterial Proteins/genetics ; *Biofilms ; Complement System Proteins/immunology ; Gene Expression Regulation, Bacterial ; Genetic Loci ; Genome, Bacterial ; Genomics/methods ; Host-Pathogen Interactions/immunology ; Hydrogen Peroxide/metabolism ; Microbial Viability/genetics ; Oxidative Stress ; Saliva/*microbiology ; Sequence Deletion ; Streptococcal Infections/immunology/metabolism/*microbiology ; Streptococcus sanguis/*physiology ; }, abstract = {Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, S. sanguinis SptRS (SptRS Ss), affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva compared to those of parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in nutrient-poor medium (RPMI) and increased susceptibility to the deposition of C3b and the membrane attach complex (MAC) of the complement system, a defense component of saliva and serum. Conversely, sptRSs and sptSSs mutants showed increased biofilm formation associated with higher levels of production of H2O2 and extracellular DNA. Reverse transcription-quantitative PCR (RT-qPCR) comparisons of strains indicated a global role of SptRS Ss in repressing genes for H2O2 production (2.5- to 15-fold upregulation of spxB, spxR, vicR, tpk, and ackA in sptRSs and sptSSs mutants), biofilm formation, and/or evasion of host immunity (2.1- to 11.4-fold upregulation of srtA, pcsB, cwdP, iga, and nt5e). Compatible with the homology of SptR Ss with AraC-type regulators, duplicate to multiple conserved repeats were identified in 1,000-bp regulatory regions of downstream genes, suggesting that SptR Ss regulates transcription by DNA looping. Significant transcriptional changes in the regulatory genes vicR, spxR, comE, comX, and mecA in the sptRSs and sptSSs mutants further indicated that SptRS Ss is part of a regulatory network that coordinates cell wall homeostasis, H2O2 production, and competence. This study reveals that SptRS Ss is involved in the regulation of crucial functions for S. sanguinis persistence in the oral cavity.}, } @article {pmid29338819, year = {2017}, author = {Zeng, R and Tong, JB and Liu, YZ and Chen, Q and Lin, T and Li, M and Lü, GX}, title = {In Vitro Efficacy of Continuous Mild High Temperature on the Biofilm Formation of Aspergillus Niger.}, journal = {Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae}, volume = {39}, number = {6}, pages = {762-767}, doi = {10.3881/j.issn.1000-503X.2017.06.005}, pmid = {29338819}, issn = {1000-503X}, mesh = {*Aspergillus niger ; Biofilms ; Microscopy, Confocal ; Temperature ; }, abstract = {Objective To investigate whether continuous mild high temperature (increased temperature without causing significant damage to host cells) can inhibit the biofilm formation of Aspergillus niger (A.niger) and its vitality.Methods A.niger biofilms were formed on a coverslip in 24-well tissue culture plate and were checked at the time points 4,8,10,16,24,48 and 72 hours.Confocal laser scanning microscopy (CLSM) was used to image and quantify A.niger biofilm formation under three different continuous mild high temperatures at 37℃,39℃,and 41℃.Furthermore,2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was used to quantify the dynamic growth of A.niger biofilm under the above conditions.Results Compared with the culture condition 37℃,CLSM analysis at 39℃ or 41℃ showed that higher temperature induced later germination at 4 hours (t=8.603,P=0.047;t=14.550,P=0.008),poorer hyphal elongation at 8 hours(t=35.118,P=0.039;t=63.450,P=0.006),poorer polar growth,and reduced biofilm thickness from 10 to 24 hours.The XTT assay showed that higher temperature (39℃ or 41℃) lead to lower vitality at 10 hours,higher vitality at 16 hours,but finally lower vitality from 24 to 72 hours (t=24.262,P=0.038;t=7.556,P=0.031).Conclusion Continuous mild high temperature may have a negative regulatory effect on biofilm formation of A.niger and its vitality.}, } @article {pmid29337088, year = {2018}, author = {Anupama, R and Sajitha Lulu, S and Mukherjee, A and Babu, S}, title = {Cross-regulatory network in Pseudomonas aeruginosa biofilm genes and TiO2 anatase induced molecular perturbations in key proteins unraveled by a systems biology approach.}, journal = {Gene}, volume = {647}, number = {}, pages = {289-296}, doi = {10.1016/j.gene.2018.01.042}, pmid = {29337088}, issn = {1879-0038}, mesh = {Bacterial Proteins/*genetics ; Biofilms/drug effects ; Gene Regulatory Networks/*genetics ; Pseudomonas aeruginosa/drug effects/*genetics ; Systems Biology/methods ; Titanium/pharmacology ; }, abstract = {A systems biology approach was used to study all the biofilm related genes of P. aeruginosa PAO1, and the interaction of titanium dioxide (TiO2) anatase with biofilm related proteins. Among the 71 genes, the interactions of all the nodal pairs were extracted by STRING 10.5 database. The inter-relationship among these genes was predicted by constructing complete PPI network and visualized in Cytoscape v 3.4.0. Total number of nodes of the network was found to be 335 and edges were 795. The network was further investigated for its clusters and the best cluster was further analyzed for the hub proteins which significantly contribute in cross-regulation of the biofilm related process. The hub proteins were identified based on four topological parameters of degree, closeness, betweeness and radiality. Four major hub proteins of P. aeruginosa PAO1 were identified to be algD, gacS, rpoS and rpoN which were common in all the hubs. Further, we have also elucidated the probable mechanism of TiO2 interaction with P. aeruginosa PAO1 at molecular level. Using STITCH server, the major target gene of TiO2 was identified as katA which also appeared commonly in our main dataset and this gene has been focused for the further study because of its unique common appearance in gene-gene network as well as gene-anatase network. The direct interacting partners of katA were found to be dnaK, hfq, rpoS and rpoA. Based on these findings and available gene regulatory information, probable TiO2 interacting cascade has been represented. This in silico study of P. aeruginosa PAO1 biofilm genes and the interaction of protein products with TiO2 might be significant to understand the perspective pathogenic resistance as well as the toxicity research pertaining to nanoparticles.}, } @article {pmid29336173, year = {2018}, author = {Raffaini, FC and Freitas, AR and Silva, TSO and Cavagioni, T and Oliveira, JF and Albuquerque Junior, RF and Pedrazzi, V and Ribeiro, RF and do Nascimento, C}, title = {Genome analysis and clinical implications of the bacterial communities in early biofilm formation on dental implants restored with titanium or zirconia abutments.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {173-182}, doi = {10.1080/08927014.2017.1417396}, pmid = {29336173}, issn = {1029-2454}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Crowns/microbiology ; Dental Abutments/*microbiology ; Dental Implants/*microbiology ; *Genome, Bacterial ; Humans ; Microbiota/*genetics ; Titanium/*chemistry ; Zirconium/*chemistry ; }, abstract = {This cross-sectional study aimed to identify and quantify up to 42 target species colonizing the early biofilm of dental implants restored with titanium or zirconia abutments. A total of 720 samples from 20 healthy individuals were investigated. Biofilm samples were collected from the peri-implant sulci, inner parts of implants, abutment surfaces and prosthetic crowns over a functioning period of 30 days. Checkerboard DNA-DNA hybridization was used for microbial detection and quantitation. Clinical characteristics (probing depth, bleeding on probing, clinical attachment level and marginal bone loss) were also investigated during the monitoring period. Genome counts were low at the implant loading time point for both the abutment materials, and increased over time. Both the titanium and the zirconia groups presented similar microbial counts and diversity over time, and the microbiota was very similar to that colonizing the remaining teeth. Clinical findings were consistent with a healthy condition with no significant difference regarding marginal bone loss between the two materials.}, } @article {pmid29334812, year = {2018}, author = {Ding, W and Ma, C and Zhang, W and Chiang, H and Tam, C and Xu, Y and Zhang, G and Qian, PY}, title = {Anti-biofilm effect of a butenolide/polymer coating and metatranscriptomic analyses.}, journal = {Biofouling}, volume = {34}, number = {1}, pages = {111-122}, doi = {10.1080/08927014.2017.1409891}, pmid = {29334812}, issn = {1029-2454}, mesh = {4-Butyrolactone/*analogs & derivatives/pharmacology ; Biofilms/*drug effects ; Biofouling/*prevention & control ; Cell Adhesion ; Metagenomics ; Microbial Consortia/*genetics ; Polyesters/*pharmacology ; Polyurethanes/*pharmacology ; Seawater ; Surface Properties ; Transcriptome ; }, abstract = {Butenolide is an environmentally friendly antifouling natural product, but its efficiency and mechanism in preventing biofilm formation have not been examined. Furthermore, controlling the release of butenolide from paints into seawater is technically challenging. A coating was developed by mixing butenolide with a biodegradable polymer, poly (ε-caprolactone)-based polyurethane, and a one-month in situ anti-biofilm test was conducted in a subtidal area. The constant release of butenolide from the surface suggested that its release was well controlled. Direct observation and confocal microscope investigation indicated that the coating was effective against both biofilm formation and attachment of large fouling organisms. Metatranscriptomic analysis of biofilm samples implied that the coating selectively inhibited the adhesion of microbes from a variety of phyla and targeted particular functional pathways including energy metabolism, drug transport and toxin release. These integrated analyses demonstrated the potential application of this butenolide/polymer coating as an anti-biofilm material.}, } @article {pmid29334249, year = {2018}, author = {Zheng, Z and Liu, Q and Kim, W and Tharmalingam, N and Fuchs, BB and Mylonakis, E}, title = {Antimicrobial activity of 1,3,4-oxadiazole derivatives against planktonic cells and biofilm of Staphylococcus aureus.}, journal = {Future medicinal chemistry}, volume = {10}, number = {3}, pages = {283-296}, pmid = {29334249}, issn = {1756-8927}, support = {P01 AI083214/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Hep G2 Cells ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Oxadiazoles/chemistry/*pharmacology ; Plankton/cytology/*drug effects ; Staphylococcus aureus/cytology/*drug effects/metabolism ; Structure-Activity Relationship ; }, abstract = {AIM: Staphylococcus aureus is a major cause of severe hospital-acquired infections, and biofilm formation is an important part of staphylococcal pathogenesis. Therefore, developing new antimicrobial agents against both planktonic cells and biofilm of S. aureus is a major challenge.

RESULTS: Three 1,3,4-oxadiazole derivatives exhibited antimicrobial activity against seven S. aureus strains in vitro, with minimum inhibitory concentrations ranging from 4 to 32 μg/ml. At 4 × minimum inhibitory concentration, all compounds killed cells within 24 h, demonstrating bactericidal activity. In addition to their effects against planktonic cells, these compounds prevented biofilm formation in a dose-dependent manner, with inhibitory concentrations for biofilm formation ranging from 8 to 32 μg/ml. Interestingly, higher concentrations of these compounds were effective against mature biofilms and all compounds downregulated the transcription of the biofilm-related gene spa.

CONCLUSION: We report three new 1,3,4-oxadiazole derivatives that have bactericidal activity and could provide as alternatives to combat S. aureus.}, } @article {pmid29334015, year = {2018}, author = {Sanford, NE and Wilkinson, JE and Nguyen, H and Diaz, G and Wolcott, R}, title = {Efficacy of hyperbaric oxygen therapy in bacterial biofilm eradication.}, journal = {Journal of wound care}, volume = {27}, number = {Sup1}, pages = {S20-S28}, doi = {10.12968/jowc.2018.27.Sup1.S20}, pmid = {29334015}, issn = {0969-0700}, mesh = {Adult ; Aged ; Aged, 80 and over ; Biofilms/*drug effects ; Enterococcus faecalis/drug effects/genetics ; Female ; Humans ; *Hyperbaric Oxygenation ; Male ; Middle Aged ; Oxygen/*pharmacology ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/drug effects/genetics ; Skin Ulcer/microbiology/nursing/*therapy ; Staphylococcus aureus/drug effects/genetics ; Time Factors ; Treatment Outcome ; Wound Healing ; }, abstract = {OBJECTIVE: Chronic wounds typically require several concurrent therapies, such as debridement, pressure offloading, and systemic and/or topical antibiotics. The aim of this study was to examine the efficacy of hyperbaric oxygen therapy (HBOT) towards reducing or eliminating bacterial biofilms in vitro and in vivo.

METHOD: Efficacy was determined using in vitro grown biofilms subjected directly to HBOT for 30, 60 and 90 minutes, followed by cell viability determination using propidium monoazide-polymerase chain reaction (PMA-PCR). The efficacy of HBOT in vivo was studied by searching our chronic patient wound database and comparing time-to-healing between patients who did and did not receive HBOT as part of their treatment.

RESULTS: In vitro data showed small but significant decreases in cell viability at the 30- and 90-minute time points in the HBOT group. The in vivo data showed reductions in bacterial load for patients who underwent HBOT, and ~1 week shorter treatment durations. Additionally, in patients' chronic wounds there was a considerable emergence of anaerobic bacteria and fungi between intermittent HBOT treatments.

CONCLUSION: The data demonstrate that HBOT does possess a certain degree of biofilm killing capability. Moreover, as an adjuvant to standard treatment, more favourable patient outcomes are achieved through a quicker time-to-healing which reduces the chance of complications. Furthermore, the data provided insights into biofilm adaptations to challenges presented by this treatment strategy which should be kept in mind when treating chronic wounds. Further studies will be necessary to evaluate the benefits and mechanisms of HBOT, not only for patients with chronic wounds but other chronic infections caused by bacterial biofilms.}, } @article {pmid29332258, year = {2018}, author = {da Silva, BGM and Carvalho, ML and Rosseti, IB and Zamuner, S and Costa, MS}, title = {Photodynamic antimicrobial chemotherapy (PACT) using toluidine blue inhibits both growth and biofilm formation by Candida krusei.}, journal = {Lasers in medical science}, volume = {33}, number = {5}, pages = {983-990}, pmid = {29332258}, issn = {1435-604X}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida/drug effects/growth & development/*physiology ; Light ; Microbial Sensitivity Tests ; *Photochemotherapy ; Photosensitizing Agents/pharmacology ; Reactive Oxygen Species/metabolism ; Tolonium Chloride/*pharmacology ; }, abstract = {Among non-albicans Candida species, the opportunistic pathogen Candida krusei emerges because of the high mortality related to infections produced by this yeast. The Candida krusei is an opportunistic pathogen presenting an intrinsic resistance to fluconazol. In spite of the reduced number of infections produced by C. krusei, its occurrence is increasing in some groups of patients submitted to the use of fluconazol for prophylaxis. Photodynamic antimicrobial chemotherapy (PACT) is a potential antimicrobial therapy that combines visible light and a nontoxic dye, known as a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells. The objective of this study was to investigate the effects of PACT, using toluidine blue, as a photosensitizer on both growth and biofilm formation by Candida krusei. In this work, we studied the effect of the PACT, using TB on both cell growth and biofilm formation by C. krusei. PACT was performed using a light source with output power of 0.068 W and peak wavelength of 630 nm, resulting in a fluence of 20, 30, or 40 J/cm[2]. In addition, ROS production was determined after PACT. The number of samples used in this study varied from 6 to 8. Statistical differences were evaluated by analysis of variance (ANOVA) and post hoc comparison with Tukey-Kramer test. PACT inhibited both growth and biofilm formation by C. krusei. It was also observed that PACT stimulated ROS production. Comparing to cells not irradiated, irradiation was able to increase ROS production in 11.43, 6.27, and 4.37 times, in the presence of TB 0.01, 0.02, and 0.05 mg/mL, respectively. These results suggest that the inhibition observed in the cell growth after PACT could be related to the ROS production, promoting cellular damage. Taken together, these results demonstrated the ability of PACT reducing both cell growth and biofilm formation by C. krusei.}, } @article {pmid30023647, year = {2017}, author = {Bagchi, D and Dutta, S and Singh, P and Chaudhuri, S and Pal, SK}, title = {Essential Dynamics of an Effective Phototherapeutic Drug in a Nanoscopic Delivery Vehicle: Psoralen in Ethosomes for Biofilm Treatment.}, journal = {ACS omega}, volume = {2}, number = {5}, pages = {1850-1857}, pmid = {30023647}, issn = {2470-1343}, abstract = {Appropriate localization of a drug and its structure/functional integrity in a delivery agent essentially dictates the efficacy of the vehicle and the medicinal activity of the drug. In the case of a phototherapeutic drug, its photoinduced dynamics becomes an added parameter. Here, we have explored the photoinduced dynamical events of a model phototherapeutic drug psoralen (PSO) in a potential delivery vehicle called an ethosome. Dynamic light scattering confirms the structural integrity of the ethosome vehicle after the encapsulation of PSO. Steady state and picosecond resolved polarization gated spectroscopy, including the well-known strategy of solvation and Förster resonance energy transfer, reveal the localization of the drug in the vehicle and the environment in the proximity of PSO. We have also investigated the efficacy of drug delivery to various individual bacteria (Gram-negative: Escherichia coli; Gram-positive: Staphylococcus aureus) and bacterial biofilms. Our optical and electron microscopic studies reveal a significant reduction in bacterial survival (∼70%) and the destruction of bacterial adherence following a change in the morphology of the biofilms after phototherapy. Our studies are expected to find relevance in the formulation of drug delivery agents in several skin diseases and biofilm formation in artificial implants.}, } @article {pmid29965157, year = {2017}, author = {Fu, KM and Zhou, HT and Su, XY and Wang, HF}, title = {[Short-cut Nitrification Recovery and Its Transformation into CANON Process in a Biofilm Reactor].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {38}, number = {4}, pages = {1536-1543}, doi = {10.13227/j.hjkx.201609233}, pmid = {29965157}, issn = {0250-3301}, mesh = {Ammonia ; *Biofilms ; *Bioreactors ; *Nitrification ; Nitrogen ; Wastewater/*chemistry ; }, abstract = {A short-cut nitrification process with modified polyethylene as carrier was operated to investigate the biofilm short-cut nitrification recovery using synthetic inorganic ammonia-rich wastewater as influent at 30℃ ±1℃. The short-cut nitrification was destroyed first by excessive aeration, and it was not built in 83 days under the condition of continuous aeration with DO less than 0.5 mg·L[-1] and free ammonia (FA) more than 1.5 mg·L[-1], which are very beneficial to short-cut nitrification. However,short-cut nitrification was realized by changing continuous aeration to intermittent aeration on 84[th] day, and it was proved again on 142[nd] day. After that, biofilm system provided a living environment for ANAMMOX bacteria, anaerobic ammonia oxidation occurred, and the biofilm short-cut nitrification process was gradually transformed into CANON process. As the load of influent and aeration increased, the total nitrogen removal efficiency and removal load increased, and the total nitrogen removal load could reach up to 2.52 kg·(m[3]·d)[-1]. Finally, in the 3rd stage, ΔNO3[-]-N/ΔTN was 0.10 on average, which means stabe short-cut nitrification in the CANON process. Therefore, once NOB was adapted to FA, it would be not very easy to recover short-cut nitrification, while intermittent aeration was an effective way, and the nitriation process would be finally transformed into CANON process, which would further improve the short-cut nitrification stability.}, } @article {pmid29965057, year = {2017}, author = {Zheng, Y and Pan, Y and Zhou, XH and Liao, XH and Meng, X and Xia, JW}, title = {[Process of Enrichment and Culture of PAOs on a Novel Biofilm Process of Dephosphorization].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {38}, number = {1}, pages = {276-282}, doi = {10.13227/j.hjkx.201607082}, pmid = {29965057}, issn = {0250-3301}, mesh = {*Biofilms ; Bioreactors/*microbiology ; In Situ Hybridization, Fluorescence ; Nylons ; Phosphorus/*isolation & purification ; *Sewage ; *Waste Disposal, Fluid ; }, abstract = {Using the hanging nylon as a biological carrier,a novel biofilm reactor was adopted to treat synthetic wastewater,and the feasibility of cultivating and enriching a high concentration of PAOs on this conventional biofilm within a short time was investigated,which was proved from the aspects of reactor's operational efficiency,the rate of phosphorus removal and the condition of PAOs enrichment.After 10d of operation,the rate of orthophosphate removal was higher than 95% in aerobic phase and the concentration of effluent COD was 50 mg·L[-1] or less in the reactor,which was operated steadily for 50 d at this treatment level;after 48 d of operation,the reactor's phosphorus uptake rate and release rate were increased from 3.4 mg·(L·h)[-1] and 3.4 mg·(L·h)[-1]to 8 mg·(L·h)[-1] and 6 mg·(L·h)[-1],respectively,and the aerobic and anaerobic cycles were shortened from equally 6 h to 2 h and 3 h,respectively.The fluorescence in situ hybridization (FISH) test found that the PAOs' abundance was increased from the original 48.96% to 70% on the 50th day,meanwhile the PAOs showed reunite chunk state in hybrid figure,the thickness of biofilm measured by direct microscopic process was about 28.9 μm,which all proved that the PAOs in biofilm were at the end of the growth kinetics and the biofilm was mature.By hardening culture for 50d,a high concentration of 70% in full organisms of PAOs could be enriched in the conventional nylon filler,enabling the reactor to show a high efficiency in removal of phosphorus and organic matter from sewage.}, } @article {pmid29644822, year = {2017}, author = {Panomket, P and Wongsana, P and Wanram, S and Wongratanacheewin, S}, title = {BURKHOLDERIA PSEUDOMALLEI BIOFILM PLAYS A KEY ROLE IN CHRONIC INFLAMMATION IN C57BL/6 MICE.}, journal = {The Southeast Asian journal of tropical medicine and public health}, volume = {48}, number = {1}, pages = {73-82}, pmid = {29644822}, issn = {0125-1562}, mesh = {Animals ; Biofilms/*growth & development ; Burkholderia pseudomallei/*physiology ; Chronic Disease ; Inflammation/*microbiology/pathology ; Melioidosis/microbiology/*pathology ; Mice ; Mice, Inbred C57BL ; }, abstract = {Burkholderia pseudomallei is a causative agent of melioidosis. Clinical signs of melioidosis vary from acute septicemia to chronic inflammation or subclinical infection. This study investigated the role of B. pseudomallei biofilm in chronic inflammation in lungs of infected C57BL/6 mice. Low doses of B. pseudomallei H777 and its biofilm defective M10 mutant were fed intra-gastrically to C57BL/6 mice and inflammatory responses were investigated by histopathological techniques. Two hundred colony forming units (CFUs) of B. pseudomallei H777 induced chronic inflammatory responses in mice on day 20 post-infection, with discrete interstitial infiltration by mononuclear inflammatory cells. On day 40 postinfection, there were marked thickening of alveolar septa and congested capillaries, which increased in severity by day 60. On the other hand, mice infected with B. pseudomallei M10 showed less mononuclear infiltration. The results indicate that B. pseudomallei defective in biofilm production gave rise to less severe pathology, resulting a higher rate of survival in infected mice; and pulmonary melioidosis could be developed in C57BL/6 mice by intra-gastric feeding makes it a possible animal model of chronic human melioidosis.}, } @article {pmid29619048, year = {2017}, author = {Hoover, J and Tovar, E and Zlatnik, T and Karunanayake, C}, title = {Efficacy of a Rinse Containing Sea Salt and Lysozyme on Biofilm and Gingival Health in a Group of Young Adults: A Pilot Study.}, journal = {International journal of dentistry}, volume = {2017}, number = {}, pages = {4056708}, pmid = {29619048}, issn = {1687-8728}, abstract = {OBJECTIVES: To evaluate new mouth rinse containing sea salt, xylitol, and lysozyme on biofilm formation and gingival health in a group of young adults.

METHODS: The subjects were divided into two groups of 15 subjects each: control (A) and experimental group (B). The Turesky modification of Quigley-Hein plaque index was used to evaluate plaque scores while the presence or absence of gingival bleeding was used to determine gingival health. Measurements were done at baseline and at the end of the one-month trial period by one blinded examiner on six representative teeth. Group (A) maintained standardized oral health practices for the duration of the experiment. In addition, group (B) rinsed with a tablespoon of the provided sea salt mouth rinse for 30 seconds once in the morning and at night. After the 30-day trial period, subjects in both groups were reassessed as per baseline. Results. There were no statistically significant differences in the overall reduction from baseline in the mean plaque and gingivitis scores on all surfaces or on individual surfaces.

CONCLUSION: Within the limitations of the study, rinsing with sea salt for thirty days did not affect the gingival and plaque scores in a group of young adults.}, } @article {pmid30230743, year = {2016}, author = {Azmy, M and Nawar, N and Mohiedden, M and Warille, L}, title = {ELECTRON MICROSCOPIC ASSAY OF BACTERIAL BIOFILM FORMED ON INDWELLING URETHRAL CATHETERS.}, journal = {Journal of the Egyptian Society of Parasitology}, volume = {46}, number = {3}, pages = {475-484}, pmid = {30230743}, issn = {1110-0583}, mesh = {Aged ; Aged, 80 and over ; Bacteria/*classification/*ultrastructure ; Biofilms/*growth & development ; Catheter-Related Infections/microbiology ; Catheters, Indwelling ; Child, Preschool ; Female ; Humans ; Infant ; Male ; *Microscopy, Electron, Scanning ; Middle Aged ; Urinary Catheters/*microbiology ; Urinary Tract Infections/microbiology ; Urine/microbiology ; }, abstract = {Biofilm formation on indwelling urinary catheters is a leading cause of Urinary tract infection (UTI). Presence of biofilm is associated with increased bacterial resistance to antimicrobial therapy and resultant treatment failure. The study detected a reliable method for diagnosis of biofilm formation by comparing scanning electron microscopy (SEM) and tissue culture plate method (TCP). The work was conducted on 20 urinary catheters from patients ranging from 1.5 to 85 years with catheters that remained in situ for a period of 3 to 20 days. Samples of catheters for culture and SEM and samples of urine were taken at the same time. The correlation between renal conditions and biofilm formation was not significant (p=0.336). No significant correlation (p =0.836, 0.163 respectively) was found between predisposing conditions (DM, renal insufficiency, diarrhea and impaired immunity) and development of Catheter associated urinary tract infection (CAUTI)and biofilm formation. Biofilm formation increased with duration of catheter in situ, but no significant.correlation was found (p=0.095). This could be due to small number of specimens. 9/20(45%) urine samples, 12/20(60%) catheter samples were positive by culture and 14/20(70%) catheters showed biofilm on SEM. 4/12(33.33%) organisms isolated from catheter culture produced biofilm by TCP method. 9 isolates were recovered from 9 positive urine cultures. The microorganisms isolated were non Candida albicans (3/9), E. coli (2/9), C. albicans (2/9) and Acenitobacter (2/9). 14 isolates were recovered from 12 culture- positive catheters. The organisms isolated were E.- coli (3/14), non-Candida albicans (3/14), C. albicans (2/14), C tropicalis (2/14), Acenitobacter (2/14), Klebsiella (1/14) and Enterococcus (1/14). Reduction in microbial diversity with antimicrobial use was noticed but the correlation was insignificant (p=0.317). The correlation between urine culture results as well as catheter culture results and biofilm formation by SEM were both significant (p = 0.008 & 0.000 respectively). The correlation between urine culture and TCP assay was insignificant (p =0.237). Using SEM as the gold standard method for the detection of biofilm, the sensitivity, specificity; total accuracy, PPV & NPV of urine culture and catheter culture were, 64.30%, 100%, 75%, 100%, 54% & 85.70%, 100%, 90%, 100%, 75% respectively.}, } @article {pmid29964680, year = {2016}, author = {Zhang, Y and Hao, RX and Xu, PC and Xu, ZQ}, title = {[Operational Characteristics of the Simultaneous Nitrogen and Phosphorus Removal and Removal of Phthalate Esters by Three-dimensional Biofilm-electrode Coupled with Iron/Sulfur Reactor].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {37}, number = {11}, pages = {4268-4274}, doi = {10.13227/j.hjkx.201604073}, pmid = {29964680}, issn = {0250-3301}, mesh = {Biofilms ; *Bioreactors ; *Denitrification ; Electrodes ; Esters ; Iron ; Nitrogen/*isolation & purification ; Phosphorus/*isolation & purification ; Phthalic Acids/*isolation & purification ; Sulfur ; Waste Disposal, Fluid ; }, abstract = {In order to explore the technological characteristics of the simultaneous removal of phthalate esters (PAEs) as well as nitrogen and phosphorus by the novel technology of three-dimensional biofilm-electrode coupled with iron/sulfur reactor (3DBER-S-Fe), the changes of the total nitrogen (TN),total phosphorus (TP),DBP,DEHP,NO3[-]-N, SO4[2-] and pH value were analyzed under the hydraulic retention time (HRT) of 8 h, 6 h and 4 h respectively. The results showed that 3DBER-S-Fe could remove nitrogen, phosphorus and PAEs effectively. Under the HRT of 8 h, 6 h and 4 h, the removal rates of TN were 80.99%, 78.85% and 64.76%; TP were 65.18%, 67.17% and 43.44%; DBP were 96.72%, 97.32% and 96.53%; DEHP were 91.89%, 81.57% and 74.30%, respectively. There were heterotrophic denitrification, hydrogen autotrophic denitrification and sulfur autotrophic denitrification processes in the 3DBER-S-Fe, the elemental sulfur could compensate for the relative shortage of denitrification electron donor caused by the increase of NO3[-]-N load in the influent as a result of maintaining a high efficiency of the denitrification system when the HRT was shortened from 8h to 4h; the iron ions produced by the corrosion of the sponge iron filler in the system had a sustainable and efficient function of removing phosphorus by precipitation; the 3DBER-S-Fe process combined the interactions of physical adsorption, biological degradation and electrochemical processes which supported its high removal rates of DBP and DEHP under the different HRT conditions.}, } @article {pmid29634108, year = {2016}, author = {Juda, M and Helon, P and Malm, A}, title = {ANTI-ADHESIVE AND ANTI-BIOFILM ACTIVITIES IN VITRO OF LINEZOLID, VANCOMYCIN, TIGECYCLINE AND DAPTOMYCIN AGAINST STAPHYLOCOCCUS HAEMOLYTICUS.}, journal = {Acta poloniae pharmaceutica}, volume = {73}, number = {6}, pages = {1539-1543}, pmid = {29634108}, issn = {0001-6837}, mesh = {Adhesiveness/drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheters/*microbiology ; Daptomycin/pharmacology ; Drug Resistance, Multiple, Bacterial ; Linezolid/pharmacology ; Microbial Sensitivity Tests ; Minocycline/analogs & derivatives/pharmacology ; Staphylococcus haemolyticus/*drug effects/physiology ; Tigecycline ; Vancomycin/pharmacology ; }, abstract = {Biofilm may be formed on wide variety of surfaces, including indwelling medical devices, leading to several infectious diseases, e.g., bacteremia and sepsis. The most,important pathogens related with infections associated with medical devices are coagulase-negative staphylococci, including Staphylococcus haeinolyticus - bacterial species which express quite often the multidrug resistance. The four clinical multiresistant and methicillin-resistant S. haenzolyticus were included in the present study. The evaluation of drug susceptibility was performed by using disc-diffusion method and broth microdilution method according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The biofilm formation on the Nelaton catheter and the effect of linezolid, vancomycin, tigecycline and daptomycin on the biofilm formation and disruption of mature structure was based on the method with TTC (2,3,5-triphenyltetrazolium chloride). The adhesion process of S. haenzolyticus to the Nelaton catheter was inhibited by antibiotics, as follows: line-zolid at concentration 0.25-0.5 x MIC, vancomycin - concentration 0.5 x MIC, tigecycline - concentration 0.25-4 x MIC and daptomycin - concentration 0.06-1 x MIC, depending on the isolate. Linezolid inhibited the biofilm formation at concentration between 0.5-1 x MIC, vancomycin - 1-2 x MIC, tigecycline - 0.5-4 x MIC and daptomycin - 0.06-2 x MIC. The concentration of linezolid eradicating the mature biofilm was found to be 1-2 x MIC, vancomycin - 2-8 x MIC, tigecycline - 2-4 x MIC and daptomycin - 0.06-2 x MIC. The most active antibiotic against S. haentolyticus biofilm formation and disruption of mature structure seems to be daptomycin.}, } @article {pmid29334058, year = {2016}, author = {Mechri, B and Medhioub, A and Medhioub, MN and Aouni, M}, title = {Prevalence of Biofilm Formation and Wide Distribution of Virulence Associated Genes among Vibrio spp. Strains Isolated from the Monastir Lagoon, Tunisia.}, journal = {Polish journal of microbiology}, volume = {65}, number = {3}, pages = {307-318}, doi = {10.5604/17331331.1215610}, pmid = {29334058}, issn = {1733-1331}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/*genetics/metabolism ; *Biofilms/drug effects ; Chlorocebus aethiops ; Genotype ; Humans ; Seawater/microbiology ; Tunisia ; Vero Cells ; Vibrio/drug effects/genetics/isolation & purification/*physiology ; Vibrio Infections/*microbiology ; Virulence Factors/*genetics/metabolism ; }, abstract = {In the current study, 65 Vibrio spp. were isolated from the Monastir lagoon water, were characterized phenotypically and genotypically. In addition, we looked for the presence of three Vibrio parahaemolyticus virulence genes (tlh, trh and tdh) and ten Vibrio cholerae virulence genes (ctxA, vpi, zot, ace, toxR, toxT, tosS, toxRS, tcpA and cpP). We also investigated the antibiotic susceptibilities and the adherence ability of the identified strains to abiotic material and to biotic surfaces. The cytotoxicity activity against HeLa and Vero cell lines were also carried out for all tested strains. All Vibrio isolates were identified to the species level and produced several hydrolytic exoenzymes. The results also revealed that all strains were expressing high rates of resistance to tested antibiotics. The minimum inhibitory concentration (MIC) values showed that tetracycline and chloramphenicol were the most effective antibiotics against the tested bacteria. Vibrio alginolyticus and V. cholerae species were the most adhesive strains to both biotic and abiotic surfaces. Besides, V. alginolyticus isolates has the high levels of recombination of genes encoding V. cholerae and V. parahaemolyticus virulence factors. In vitro cytotoxic activities of several Vibrio extracellular product were also observed among HeLa and Vero cells.}, } @article {pmid29964738, year = {2016}, author = {Liu, C and Yu, CF and Zhang, J and Chen, XX and Zhang, L and Yang, JL}, title = {[Operation Performance of a Bioaugmented Membrane-aerated Biofilm Reactor Treating Atrazine Wastewater].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {37}, number = {8}, pages = {3101-3107}, doi = {10.13277/j.hjkx.2016.08.035}, pmid = {29964738}, issn = {0250-3301}, mesh = {Atrazine/*isolation & purification ; *Biofilms ; Bioreactors/*microbiology ; Microorganisms, Genetically-Modified ; *Waste Disposal, Fluid ; Wastewater/*chemistry ; }, abstract = {A hydrophobic SPG (shirasu porous glass) membrane-aerated biofilm reactor (MABR) with genetically engineered microorganism (GEM) biofilm formed on the SPG membrane surface was applied to treat atrazine wastewater. The contaminant removal performance and its influencing factors were investigated during the stable operation of this MABR. The results indicated that the oxygen supply capacity could be increased in the SPG membrane aeration when the membrane pore size and the aeration pressure increased, which could improve the performance of COD and atrazine removals. The maximum oxygen supply capacity of hydrophobic SPG membrane with pore size of 1.5 μm was estimated to be about 22.4 g·(m[2]·d)[-1] at aeration pressure of 70 kPa. When aeration pressure was 70 kPa and hydraulic retention time (HRT) was 1.5 h, the average COD removal efficiency was 80.1% and the average organic loading rate removed was 1.86 kg·(m[3]·d)[-1]in the MABR with 1.5 μm hydrophobic SPG membrane. Under the same operating conditions, the average atrazine removal efficiency was 62.5% and the average atrazine loading rate removed was 0.18 kg·(m[3]·d)[-1]. The COD and atrazine removal efficiencies decreased significantly at further shortened HRT and increased influent organic loading rate. DO concentration showed more significant influence on atrazine removal. The simplex genetically engineered microorganism biofilm turned into complex microbial community gradually during MABR operation, but the GEM cells could still reside in the biofilm well. Therefore, the efficient atrazine removal by GEM bioaugmentation could be maintained.}, } @article {pmid29738196, year = {2016}, author = {Qiao, R and Xie, K and Xie, M}, title = {[Inhibition of methicillin-resistant Staphylococcus aureus biofilm by honokiol].}, journal = {Wei sheng wu xue bao = Acta microbiologica Sinica}, volume = {56}, number = {8}, pages = {1266-1272}, pmid = {29738196}, issn = {0001-6209}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Biphenyl Compounds/*pharmacology ; Drugs, Chinese Herbal/*pharmacology ; Humans ; Lignans/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/physiology ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; }, abstract = {OBJECTIVE: To study the inhibition of methicillin-resistant Staphylococcus aureas (MRSA) biofilm by honokiol.

METHODS: We used triphenyl tetrazolium chloride method to evaluate the inhibition of biofilm formation and mature by honokiol. We used congo red agar and spectrophotometer to detect the influence of honokiol on polysaccharide intercellular adhesion formation and extracellular DNA release. RT-PCR analysis was used to determine the effect of honokiol on expression of icaA, cidA and agrA.

RESULTS: Honokiol showed strong antimicrobial activity both on biofilm formation and mature biofilm of MRSA 41573. Minimum inhibitory concentration was 10 μg/mL for biofilm formation and 50 μg/mL for mature biofilm. Minimum bactericidal concentration was 20 μg/mL for biofilm formation and 100 μg/mL for mature biofilm. Honokiol showed synergy effect with vancomycin and it significantly increased the sensitivity of mature biofilm to vancomycin. Polysaccharide intercellular adhesion formation and extracellular DNA release were effectively inhibited by honokiol. Extracellular DNA release decreased by 28.3% when honokiol at 1/8 MIC. After incubated with 1/2 MIC of honokiol for 16 h, the relative expression of icaA, cidA and agrA of MRSA41573 was reduced by 59.1%, 56% and 72.3%, respectively.

CONCLUSION: Honokiol can significantly inhibit biofilm formation of MRSA41573 and its mechanism is mainly the inhibited expression of icaA and cidA to influence the synthesis of polysaccharide intercellular adhesion and extracellular DNA. Moreover, it also affect biofilm formation by QS system.}, } @article {pmid30108790, year = {2017}, author = {Garrison, AT and Abouelhassan, Y and Yang, H and Yousaf, HH and Nguyen, TJ and Huigens Iii, RW}, title = {Microwave-enhanced Friedländer synthesis for the rapid assembly of halogenated quinolines with antibacterial and biofilm eradication activities against drug resistant and tolerant bacteria.}, journal = {MedChemComm}, volume = {8}, number = {4}, pages = {720-724}, pmid = {30108790}, issn = {2040-2503}, abstract = {Herein, we disclose the development of a catalyst- and protecting-group-free microwave-enhanced Friedländer synthesis which permits the single-step, convergent assembly of diverse 8-hydroxyquinolines with greatly improved reaction yields over traditional oil bath heating (increased from 34% to 72%). This rapid synthesis permitted the discovery of novel biofilm-eradicating halogenated quinolines (MBECs = 1.0-23.5 μM) active against MRSA, MRSE, and VRE. These small molecules exhibit activity through mechanisms independent of membrane lysis, further demonstrating their potential as a clinically useful treatment option against persistent biofilm-associated infections.}, } @article {pmid29964477, year = {2016}, author = {Cheng, PF and Wang, Y and Yang, QY and Tang, M and Liu, TZ}, title = {[Coupling of Hydrocarbon Accumulation and Cobalt Removal During Treatment of Cobalt Enriched Industrial Wastewater with Botryococcus braunii Biofilm Attached Cultivation].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {37}, number = {7}, pages = {2666-2672}, doi = {10.13227/j.hjkx.2016.07.033}, pmid = {29964477}, issn = {0250-3301}, mesh = {*Biofilms ; *Chlorophyta ; Cobalt/*isolation & purification ; Hydrocarbons/*isolation & purification ; Wastewater/*chemistry ; *Water Purification ; }, abstract = {Industrial wastewater pollution is an increasing problem. The wastewater infiltrated cobalt is a key to purify wastewater because it is seriously hazardous and hard to treat. Traditional management method of heavy metals in industrial wastewater is difficult to apply. To seek for "green ecological" feasible approaches of industrial wastewater treatment, this paper studied the effect of industrial wastewater containing cobalt on the growth and hydrocarbon accumulation of Botryococcus braunii SAG 807-1 with biofilm attached cultivation. The research results obtained were as follows:B.braunii with biofilm attached cultivation could treat industrial wastewater, and 4.5 mg·L[-1] cobalt could accelerate the accumulation of hydrocarbon while having little influence on the growth of B.braunii, the ability of B.braunii with biofilm attached cultivation to remove Co[2+] from industrial wastewater was 1473.9 μmol·g[-1], which was much higher than the report of P. littoralis culture. Through the study in this paper, the theoretical basis for the coupling of production of green high energy fuel hydrocarbon and industrial wastewater treatment was established.}, } @article {pmid29964472, year = {2016}, author = {Liu, C and Zhang, J and Zhang, J and Chen, XX and Zhang, L and Cao, LY}, title = {[Performance Evaluation of a Pilot-scale Microbubble-aerated Biofilm Reactor].}, journal = {Huan jing ke xue= Huanjing kexue}, volume = {37}, number = {7}, pages = {2632-2638}, doi = {10.13227/j.hjkx.2016.07.028}, pmid = {29964472}, issn = {0250-3301}, mesh = {*Biofilms ; *Bioreactors ; Microbubbles ; Nitrogen/*isolation & purification ; Oxidation-Reduction ; Oxygen/metabolism ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {A pilot-scale microbubble-aerated biofilm reactor was operated to treat campus domestic wastewater and its performance was evaluated and compared with conventional biological treatment processes. The results indicated that when the raw campus domestic wastewater was treated in the pilot system, the average COD removal efficiency and loading rate removed were 57.0% and 2.68 kg·(m[3]·d)[-1]; the average ammonia nitrogen removal efficiency and loading rate removed were 17.4% and 0.17 kg·(m[3]·d)[-1]; the average total nitrogen (TN) removal efficiency and loading rate removed were 15.8% and 0.21 kg·(m[3]·d)[-1]; and the average oxygen utilization efficiency reached 100%. When the effluent of biological contact oxidation tank with poor biodegradability was treated in the pilot system, the average COD removal efficiency and loading rate removed were 46.0% and 1.53 kg·(m[3]·d)[-1]; the average ammonia nitrogen removal efficiency and loading rate removed were 17.1% and 0.32 kg·(m[3]·d)[-1]; the average total nitrogen (TN) removal efficiency and loading rate removed were 14.1% and 0.28 kg·(m[3]·d)[-1]; and the average oxygen utilization efficiency was higher than 50%. Furthermore, the contaminant removal performance of the pilot system was much more efficient than conventional biological contact oxidation tank and biological aeration filter tank with the same influent quality, since oxygen transfer and oxygen utilization could be enhanced by microbubble aeration.}, } @article {pmid29786326, year = {2016}, author = {Wang, X and Huang, Y and Zhou, Y and Liu, D and Lü, Z and Ye, L and Chen, Y and Yang, J and Chen, P and Wang, Z}, title = {[Effect of estradiol on biofilm formation of staphylococcus epidermidis after breast implant surgery].}, journal = {Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery}, volume = {30}, number = {7}, pages = {876-884}, doi = {10.7507/1002-1892.20160178}, pmid = {29786326}, issn = {1002-1892}, abstract = {OBJECTIVE: ?To investigate the effect of the estradiol hormones on biofilm formati on and structure of Staphylococcus epidermidis after breast implant surgery.

METHODS: ?The concentration of Staphylococcus epidermidis strains ATCC35984 was adjusted to 1×10[7] CFU/mL or 1×10[8] CFU/mL, and the type strains were incubated on the surface of silica gel in 125 pmol/L estradiol suspensions to prepare bacterial biofilms model in vitro. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, bacteria growth and biofilm formation ability were assessed by means of the XTT and crystal violet staining respectively. According to the above results, the bacterial suspension concentration was selected for experiments. The experimental concentration of Staphylococcus epidermidis ATCC35984 suspension and the concentrations of 50, 125, 250, 500 pmol/L estradiol suspensions were mixed with silica gel respectively to prepare biofilm model in vitro, no estradiol suspension served as control group. The experimental concentration of Staphylococcus epidermidis ATCC12228 suspension was used to prepare the same model in the negative control. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, the same methods were used to assess the bacteria growth dynamics and biofilm forming ability, and the scanning electron microscope (SEM) was used to observe bacterial biofilm structure cultured on the surface of silica gel; the laser scanning confocal microscope (CLSM) was used to measure bacterial biofilm thickness on the surface of silica gel after 6, 12, and 24 hours.

RESULTS: ?According to the results of semi quantitative detection of crystal violet stain and XTT methods, the bacterial suspension of 1×10[7] CFU/mL was selected for the experiment. XTT results indicated that the growth rates of ATCC12228 strain (at 4, 6, 12, 24, and 72 hours) and ATCC35984 strain (at 4, 6, 24, and 72 hours) in 125, 250, and 500 pmol/L estradiol were significantly faster than those in 0 and 50 pmol/L (P<0.05). The growth rate of 500 pmol/L group was significantly faster than 125 and 250 pmol/L groups at 4, 6, and 72 hours (P<0.05), and the growth rate of 250 pmol/L group was significantly faster than that of 125 pmol/L group at 72 hours (P<0.05), but there was no significant difference between 0 and 50 pmol/L groups (P>0.05). At the same time point and same estradiol concentration, the growth rates showed no significant difference between 2 strains (P>0.05). Semi quantitative detection of crystal violet staining showed no biofilm formed in ATCC12228 strain in all estradiol concentration groups at different time points. In ATCC35984 strain, the biofilm was found at 4 hours and gradually thickened with time, reached the peak at 24 hours. After cultured for 4 and 6 hours, the biofilm of 0 pmol/L groups were significantly thicker than that of 125, 250, and 500 pmol/L groups (P<0.05). At 12 hours, the 125 pmol/L group had the thickest biofilm, showing significant difference when compared with other groups (P<0.05). The CLSM showed ATCC35984 biofilm thickness of 125, 250, and 500 pmol/L was significantly less than that of 0 and 50 pmol/L groups at 6 hours (P<0.05), but difference was not significant between other groups (P>0.05). Then the thickness of the biofilm increased gradually, and the thickness of 125 pmol/L group was significantly larger than that of other concentration groups at 12 and 24 hours (P<0.05). The SEM observation showed that the biofilm of 125 pmol/L group was denser and thicker than that of the other concentration groups at each time point.

CONCLUSIONS: ?High level estradiol can promote bacteria growth, biofilm formation, and biofilm maturity of Staphylococcus epidermidis.}, } @article {pmid29727147, year = {2016}, author = {Zhang, F and Zhu, J and Feng, L}, title = {[Inhibition analysis of resveratrol against Vibrio parahaemolyticus biofilm based on RNA-Seq technology].}, journal = {Wei sheng wu xue bao = Acta microbiologica Sinica}, volume = {56}, number = {5}, pages = {856-866}, pmid = {29727147}, issn = {0001-6209}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Resveratrol ; Sequence Analysis, RNA ; Stilbenes/*pharmacology ; Vibrio parahaemolyticus/*drug effects/genetics/*physiology ; }, abstract = {OBJECTIVE: Food phytochemicals as biofilm inhibitor of pathogens have been highlighted. Our study aimed to investigate the effects of resveratrol on biofilm formation of an aquatic pathogen Vibrio parahaemolyticus, and to elucidate the important regulatory genes.

METHODS: In the subinhibitory concentrations, the inhibition of resveratrol aganist biofilm and exopolysaccharides of V. parahaemolyticus was detected, and the differentially expressed genes were analyzed based on RNA-Seq. Four genes involved in biofilm formation was validated by qRT-PCR.

RESULTS: The minimum inhibitory concentration of resveratrol against V. parahaemolyticus was 20 μg/mL. Resveratrol at the subinhibitory concentration of 5 μg/mL and 10 μg/mL significantly decreased the biofilm development and exopolysaccharides production in V. parahaemolyticus (P < 0.05). Scanning electron microscopy micrographs showed a significant reduction of adherence and extracellular polymeric substances. RNA-Seq analysis revealed that 22.6% up-regulated and 77.4% down-regulated gene (P < 0.05) after treatment by 10 μg/mL resveratrol among 106 differential gene expressions. These differential genes in V. parahaemolyticu focused on 7 metabolic pathways, and 14 genes involved in biofilm formation were down-regulated by resveratrol, such as outer membrane protein (W, YedS, OmpK), quorum sensing (LuxS), flagellin (FlaA), fimbrial assembly protein (PilQ), hemolysin secreted protein. qRT-PCR confirmed that the expressions of luxS, trh, tlh and flaA, was significantly repressed in the presence of resveratrol, which was consistent with transcriptomics data.

CONCLUSION: Inhibitory activity of resveratrol on biofilm formation was assicated with multiple genes and diverse cellular processes in V. parahaemolyticus. These findings suggest that resveratrol would disturb various metabolic pathways, particularly quorum sensing system, adhesion process and membrane proteins secretion, resulting in inhibition of attachment and biofilm development. The present work provided valuable information to explore molecular mechanism of resveratrol as an novel anti-biofilm compound.}, } @article {pmid29509387, year = {2016}, author = {Gabisoniya, TG and Loladze, MZ and Nadiradze, MM and Chakhunashvili, NK and Alibegashvili, MG and Tamarashvili, NG and Pushkina, VA}, title = {[Effects of bacteriophages on biofilm formation by strains of Pseudomonas aeruginosa].}, journal = {Prikladnaia biokhimiia i mikrobiologiia}, volume = {52}, number = {3}, pages = {312-317}, pmid = {29509387}, issn = {0555-1099}, mesh = {Biofilms/*growth & development ; Pseudomonas Phages/*growth & development ; Pseudomonas aeruginosa/*physiology/*virology ; }, abstract = {The effects of two Pseudomonas aeruginosa bacteriophages, vB-Pa 4 and vB-Pa 5, on the formation and development of biofilms of six polyresistant hospital strains of P. aeruginosa have been investigated. Pretreatment of bacteriophages prevented the formation or almost completely prevented the growth of adequate biofilms. The biofilms that had already formed were partially or completely destroyed after phage treatment. The results demonstrate the prospects of using isolated bacteriophages of P. aeruginosa to destroy biofilms and prevent their formation.}, } @article {pmid29539252, year = {2016}, author = {Besednova, NN and Makarenkova, ID and Zvyagintseva, TN and Kuznetsova, TA and Zaporozhets, TS}, title = {Inhibitory Effect of Polysaccharides of Marine Hydrobionts on Biofilm Formation.}, journal = {Antibiotiki i khimioterapiia = Antibiotics and chemoterapy [sic]}, volume = {61}, number = {9-10}, pages = {64-73}, pmid = {29539252}, issn = {0235-2990}, abstract = {In the review there are considered the recent data on the perspectives of the use of polysaccharides (PS) from marine hydrobionts for nhibition of formation of bacterial biofilms, which play a significant role in the onset and process of different infections, as well as for design of antiadhesive coatings on medical produce. Particular attention is paid to antiadhesive properties of natural PS from marine microorganisms, algae and invertebrate animals, which prevent formation of biofilms. Antibiofilm PS possess such positive characteristics, as biocompatibility and biodegradability, that is of great interest for medical and industrial applications. The possibility of simultaneous use of complexes of compounds of different chemical nature and mechanisms of action in infectious diseases, involving biofilm formation is of special interest. It is believed that biologically active substances from marine hydrobionts could serve as the basis for development of new antibiofilm drugs, including complex ones.}, } @article {pmid29364983, year = {2014}, author = {Lazar Adler, NR and Dean, RE and Saint, RJ and Stevens, MP and Prior, JL and Atkins, TP and Galyov, EE}, title = {Correction: Identification of a Predicted Trimeric Autotransporter Adhesin Required for Biofilm Formation of Burkholderia pseudomallei.}, journal = {PloS one}, volume = {9}, number = {1}, pages = {}, doi = {10.1371/annotation/f016476b-5b84-4c9a-899f-fe8b8bc927b5}, pmid = {29364983}, issn = {1932-6203}, abstract = {[This corrects the article DOI: 10.1371/journal.pone.0079461.].}, } @article {pmid29334054, year = {2012}, author = {Serefko, AD and Poleszak, EJ and Malm, A}, title = {Candida albicans Denture Biofilm and its Clinical Significance.}, journal = {Polish journal of microbiology}, volume = {61}, number = {3}, pages = {161-167}, pmid = {29334054}, issn = {1733-1331}, abstract = {Fungi belonging to Candida genus, especially C. albicans play an important role in microflora of oral cavity. Microbial colonisation process taking place within oral cavity is inseparably related to formation of multispecies biofilm, i.e. dental and denture plaque. A mature fungal biofilm is a heterogeneous three-dimensional dense conglomeration of mixture of different morphological forms: blastospores, germ tubes, pseudohyphae and hyphae surrounded by the extracellular polymeric matrix. Composition and specific properties of substratum, saliva and yeasts as well as multiple intricate interactions between all of them influence the ability of Candida spp. isolates to adhere and colonise both natural and artificial surfaces, followed by biofilm formation. Obviously, specific complex host-pathogen interactions also should not be neglected. A lot of additional factors like poor oral and denture hygiene, low pH under prosthesis, sufficient concentration of sugar and iron or antibody titres influence Candida adhesion and colonisation of acrylic resin base. C. albicans is capable of inducing a variety of superficial diseases of the oral mucosa. The most common clinical form of oral candidal infection related to biofilm formation affecting a great deal of denture wearers is denture-associated stomatitis, also known as chronic atrophic candidiasis or erythemateous candidasis. Development of C. albicans biofilm on a denture surface constitutes a difficult and hard to resolve problem which may concern every single prosthesis-wearer. Thus, careful oral and denture hygiene is highly recommended for the population of artificial teeth wearers.}, } @article {pmid29539045, year = {2005}, author = {Kuramitsu, HK and Chen, W and Ikegami, A}, title = {Biofilm Formation by the Periodontopathic Bacteria Treponema denticola and Porphyromonas gingivalis.}, journal = {Journal of periodontology}, volume = {76 Suppl 11S}, number = {}, pages = {2047-2051}, doi = {10.1902/jop.2005.76.11-S.2047}, pmid = {29539045}, issn = {1943-3670}, abstract = {BACKGROUND: Periodontitis develops as a result of the interaction of the host with subgingival plaque bacteria. Both Porphyromonas gingivalis and Treponema denticola are frequently associated together in these oral biofilms.

METHODS: The molecular basis for in vitro biofilm formation was investigated for P. gingivalis 381, T. denticola 35405, and mixtures of the two organisms using microtiter plate assays. In addition, the biofilms were examined following confocal laser scanning microscopy.

RESULTS: P. gingivalis 381, but not T. denticola strains, formed biofilms in vitro. This property was dependent, in part, on the strain 381 fimA, ppk, and usp genes. Microarray and Northern blot analyses suggested that the expression of the ppk gene was required for maximal expression of the uspA gene. P. gingivalis 381 formed synergistic biofilms when incubated with T. denticola strains. This process was dependent upon the strain 381 rgpB and fimA genes as well as the T. denticola flgE and cfpA genes.

CONCLUSIONS: P. gingivalis 381 formed synergistic biofilms with T. denticola 35405. These results may be relevant to the previous observations that the two organisms are frequently observed together in subgingival plaque with the spirochetes localized to the exterior of the oral biofilms. It is suggested that other such synergistic effects may also occur between other plaque bacteria.}, } @article {pmid29331510, year = {2018}, author = {Sun, Y and Chen, S and Zhang, C and Liu, Y and Ma, L and Zhang, X}, title = {Effects of sub-minimum inhibitory concentrations of lemon essential oil on the acid tolerance and biofilm formation of Streptococcus mutans.}, journal = {Archives of oral biology}, volume = {87}, number = {}, pages = {235-241}, doi = {10.1016/j.archoralbio.2017.12.028}, pmid = {29331510}, issn = {1879-1506}, mesh = {Biofilms/*drug effects ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; Plant Oils/*pharmacology ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*drug effects ; }, abstract = {OBJECTIVES: Lemon essential oil (LEO) is a kind of secondary metabolite from lemon peels and has been found to inhibit cariogenic bacteria for decades. However, its effects on main cariogenic virulence factors are rarely reported. The present study aimed to investigate the effects of sub-minimum inhibitory concentrations (sub-MICs) of LEO on the acid tolerance and biofilm formation of Streptococcus mutans (S. mutans) and preliminarily reveal the possible underlying mechanisms.

DESIGNS: Effects of LEO on the acid tolerance and biofilm formation of S. mutans were investigated by the broth dilution method and crystal violet staining method respectively. The expression of luxS, srtA and spaP gene was also determined to explore the underlying mechanism. In addition, Tea polyphenols (TP), a major natural inhibitor of cariogenic virulence factors, and limonene (LIM), the major component of LEO, were selected as comparisons to evaluate the effects of LEO.

RESULTS: Sub-MICs of LEO, LIM and TP exhibited a dose-dependent inhibition of growth of S. mutans at pH ranging from 4.0 to 7.0. The formation of S. mutans biofilm was remarkably inhibited and the inhibitory rates of LEO, LIM and TP were 97.87%, 94.88% and 96.01% respectively at 1/2 MIC. Similarly, a down-regulation was observed in the expression of luxS, srtA and spaP gene at sub-MIC levels.

CONCLUSIONS: Effects of LEO were similar or slightly stronger than LIM and TP, suggesting that LEO might represent a novel, natural anticarious agent that inhibited the specific genes associated with bacterial acid tolerance and biofilm formation without necessarily affecting the growth of oral bacteria.}, } @article {pmid29330591, year = {2018}, author = {Zabłotni, A and Matusiak, D and Arbatsky, NP and Moryl, M and Maciejewska, A and Kondakova, AN and Shashkov, AS and Ługowski, C and Knirel, YA and Różalski, A}, title = {Changes in the lipopolysaccharide of Proteus mirabilis 9B-m (O11a) clinical strain in response to planktonic or biofilm type of growth.}, journal = {Medical microbiology and immunology}, volume = {207}, number = {2}, pages = {129-139}, pmid = {29330591}, issn = {1432-1831}, support = {B1311000000096.02//Ministry of Science and Higher Education in Poland/ ; B1411000000768.02//Ministry of Science and Higher Education in Poland/ ; B1511000001043.02//Ministry of Science and Higher Education in Poland/ ; }, mesh = {Biofilms/*growth & development ; Blotting, Western ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Humans ; Lipopolysaccharides/*analysis/isolation & purification ; Magnetic Resonance Spectroscopy ; Proteus Infections/microbiology ; Proteus mirabilis/*chemistry/*growth & development/isolation & purification ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Staining and Labeling ; }, abstract = {The impact of planktonic and biofilm lifestyles of the clinical isolate Proteus mirabilis 9B-m on its lipopolysaccharide (O-polysaccharide, core region, and lipid A) was evaluated. Proteus mirabilis bacteria are able to form biofilm and lipopolysaccharide is one of the factors involved in the biofilm formation. Lipopolysaccharide was isolated from planktonic and biofilm cells of the investigated strain and analyzed by SDS-PAGE with silver staining, Western blotting and ELISA, as well as NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry techniques. Chemical and NMR spectroscopic analyses revealed that the structure of the O-polysaccharide of P. mirabilis 9B-m strain did not depend on the form of cell growth, but the full-length chains of the O-antigen were reduced when bacteria grew in biofilm. The study also revealed structural modifications of the core region in the lipopolysaccharide of biofilm-associated cells-peaks assigned to compounds absent in cells from the planktonic culture and not previously detected in any of the known Proteus core oligosaccharides. No differences in the lipid A structure were observed. In summary, our study demonstrated for the first time that changes in the lifestyle of P. mirabilis bacteria leads to the modifications of their important virulence factor-lipopolysaccharide.}, } @article {pmid29330184, year = {2018}, author = {Raghupathi, PK and Zupančič, J and Brejnrod, AD and Jacquiod, S and Houf, K and Burmølle, M and Gunde-Cimerman, N and Sørensen, SJ}, title = {Microbial Diversity and Putative Opportunistic Pathogens in Dishwasher Biofilm Communities.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {5}, pages = {}, pmid = {29330184}, issn = {1098-5336}, mesh = {Bacteria/growth & development/isolation & purification ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Fungi/growth & development/isolation & purification/*physiology ; *Household Articles ; Microbiota/*physiology ; }, abstract = {Extreme habitats are not only limited to natural environments, but also exist in manmade systems, for instance, household appliances such as dishwashers. Limiting factors, such as high temperatures, high and low pHs, high NaCl concentrations, presence of detergents, and shear force from water during washing cycles, define microbial survival in this extreme system. Fungal and bacterial diversity in biofilms isolated from rubber seals of 24 different household dishwashers was investigated using next-generation sequencing. Bacterial genera such as Pseudomonas, Escherichia, and Acinetobacter, known to include opportunistic pathogens, were represented in most samples. The most frequently encountered fungal genera in these samples belonged to Candida, Cryptococcus, and Rhodotorula, also known to include opportunistic pathogenic representatives. This study showed how specific conditions of the dishwashers impact the abundance of microbial groups and investigated the interkingdom and intrakingdom interactions that shape these biofilms. The age, usage frequency, and hardness of incoming tap water of dishwashers had significant impact on bacterial and fungal community compositions. Representatives of Candida spp. were found at the highest prevalence (100%) in all dishwashers and are assumed to be one of the first colonizers in recently purchased dishwashers. Pairwise correlations in tested microbiomes showed that certain bacterial groups cooccur, as did the fungal groups. In mixed bacterial-fungal biofilms, early adhesion, contact, and interactions were vital in the process of biofilm formation, where mixed complexes of bacteria and fungi could provide a preliminary biogenic structure for the establishment of these biofilms.IMPORTANCE Worldwide demand for household appliances, such as dishwashers and washing machines, is increasing, as is the number of immunocompromised individuals. The harsh conditions in household dishwashers should prevent the growth of most microorganisms. However, our research shows that persisting polyextremotolerant groups of microorganisms in household appliances are well established under these unfavorable conditions and supported by the biofilm mode of growth. The significance of our research is in identifying the microbial composition of biofilms formed on dishwasher rubber seals, how diverse abiotic conditions affect microbiota, and which key microbial members were represented in early colonization and contamination of dishwashers, as these appliances can present a source of domestic cross-contamination that leads to broader medical impacts.}, } @article {pmid29329011, year = {2018}, author = {El-Taliawy, H and Casas, ME and Bester, K}, title = {Removal of ozonation products of pharmaceuticals in laboratory Moving Bed Biofilm Reactors (MBBRs).}, journal = {Journal of hazardous materials}, volume = {347}, number = {}, pages = {288-298}, doi = {10.1016/j.jhazmat.2018.01.002}, pmid = {29329011}, issn = {1873-3336}, mesh = {Anti-Bacterial Agents/chemistry ; Anti-Inflammatory Agents, Non-Steroidal/chemistry ; Biofilms ; *Bioreactors ; Diclofenac/chemistry ; Laboratories ; Macrolides/chemistry ; Oxides/chemistry/metabolism ; Ozone/*chemistry ; Waste Disposal, Fluid/methods ; Water Pollutants, Chemical/*chemistry/*metabolism ; }, abstract = {The major pathway of pharmaceuticals from urban applications to urban surface waters is via wastewater treatment plants. Ozonation is able to remove pharmaceuticals from wastewater effluents. However, during that reaction, ozonation products are formed. Some ozonation products were found to be persistent and have adverse effect on the environment. Moving bed bio reactors (MBBRs) were tested for the removal of the ozonation products of macrolide antibiotics and diclofenac at two different concentration levels 1 μg/L and 10 μg/L in laboratory reactors. It was found that the MBBRs are capable of degrading these compounds without back-transformation into the parent compounds. However, reaction rate constants and the degradation kinetics varied for different compounds and different concentrations. Depending on compound and conditions, the degradation reaction kinetics was found to follow either i) zero order ii) first order or iii) lag phase succeeded by first order. The study has proven that MBBRs have the potential to be efficient in polishing post ozonation treatment.}, } @article {pmid29327470, year = {2018}, author = {Stenhouse, M and Zilm, P and Ratnayake, J and Cathro, P}, title = {Investigation of the effect of rapid and slow external pH increases on Enterococcus faecalis biofilm grown on dentine.}, journal = {Australian dental journal}, volume = {63}, number = {2}, pages = {224-230}, doi = {10.1111/adj.12582}, pmid = {29327470}, issn = {1834-7819}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Buffers ; Calcium Hydroxide/*pharmacology ; Cell Survival ; Dental Pulp Cavity/drug effects ; Dentin/*microbiology ; Enterococcus faecalis/*drug effects ; Humans ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning ; Root Canal Irrigants/pharmacology ; Root Canal Therapy ; }, abstract = {BACKGROUND: Calcium hydroxide is a common endodontic medicament and has an antimicrobial effect by increasing the localized pH within the root canal. However, Enterococcus faecalis has shown some resistance to calcium hydroxide.

METHODS: A flow cell apparatus was used to grow an E. faecalis biofilm on dentine discs. Following 4 weeks growth in Todd Hewitt Broth, flow cells were exposed to either a rapid or slow increase to pH 11.5 or 12.5. Cellular viability was determined using serial plating and the number of colony-forming units was normalized against the cellular protein content. Scanning electron microscopy was carried out to qualitatively observe the effects of the different rates of pH increase.

RESULTS: A significant difference in viability between the pH rapid and slow groups was not shown in this study. Compared with pH 11.5 solutions, pH 12.5 solutions were more effective at killing bacteria although some E. faecalis still survived.

CONCLUSIONS: Enterococcus faecalis did not adapt and develop a greater resistance to high pH following a slow rise in pH compared with a rapid rise in pH. As expected, pH 12.5 was more effective in reducing bacterial numbers compared with pH 11.5 although E. faecalis was not completely eliminated.}, } @article {pmid29327068, year = {2018}, author = {Kang, J and Li, Q and Liu, L and Jin, W and Wang, J and Sun, Y}, title = {The specific effect of gallic acid on Escherichia coli biofilm formation by regulating pgaABCD genes expression.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {4}, pages = {1837-1846}, doi = {10.1007/s00253-017-8709-3}, pmid = {29327068}, issn = {1432-0614}, support = {31301472//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Biofilms/*drug effects/*growth & development ; Colony Count, Microbial ; Escherichia coli/*drug effects/physiology ; Escherichia coli Proteins/*biosynthesis ; Gallic Acid/*metabolism ; Gene Expression Regulation, Bacterial/*drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Real-Time Polymerase Chain Reaction ; Staining and Labeling/methods ; beta-Glucans/metabolism ; }, abstract = {Escherichia coli (E. coli) is associated with an array of health-threatening contaminations, some of which are related to biofilm states. The pgaABCD-encoded poly-beta-1,6-N-acetyl-D-glucosamine (PGA) polymer plays an important role in biofilm formation. This study was conducted to determine the inhibitory effect of gallic acid (GA) against E. coli biofilm formation. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of GA against planktonic E. coli were 0.5 and 4 mg/mL, and minimal biofilm inhibitory concentration and minimal biofilm eradication concentration values of GA against E. coli in biofilms were 2 and 8 mg/mL, respectively. Quantitative crystal violet staining of biofilms and ESEM images clearly indicate that GA effectively, dose-dependently inhibited biofilm formation. CFU counting and confocal laser scanning microscopy measurements showed that GA significantly reduced viable bacteria in the biofilm. The contents of polysaccharide slime, protein, and DNA in the E. coli biofilm also decreased. qRT-PCR data showed that at the sub-MIC level of GA (0.25 mg/mL) and expression of pgaABC genes was downregulated, while pgaD gene expression was upregulated. The sub-MBC level of GA (2 mg/mL) significantly suppressed the pgaABCD genes. Our results altogether demonstrate that GA inhibited viable bacteria and E. coli biofilm formation, marking a novel approach to the prevention and treatment of biofilm-related infections in the food industry.}, } @article {pmid29326887, year = {2017}, author = {Wen, ZT and Liao, S and Bitoun, JP and De, A and Jorgensen, A and Feng, S and Xu, X and Chain, PSG and Caufield, PW and Koo, H and Li, Y}, title = {Streptococcus mutans Displays Altered Stress Responses While Enhancing Biofilm Formation by Lactobacillus casei in Mixed-Species Consortium.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {524}, pmid = {29326887}, issn = {2235-2988}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; R21 DE025348/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/metabolism ; Biofilms/*growth & development ; Glucosyltransferases/metabolism ; Hydrogen Peroxide/toxicity ; Lactobacillus/*growth & development ; Microbial Consortia/*physiology ; *Microbial Interactions ; Microbial Viability/drug effects ; Streptococcus mutans/enzymology/growth & development/*physiology ; *Stress, Physiological ; }, abstract = {Like Streptococcus mutans, lactobacilli are commonly isolated from carious sites, although their exact role in caries development remains unclear. This study used mixed-species models to analyze biofilm formation by major groups of oral lactobacilli, including L. casei, L. fermentum, L. rhamnosus, L. salivarius ssp. salivarius, and L. gasseri. The results showed that lactobacilli did not form good biofilms when grown alone, although differences existed between different species. When grown together with S. mutans, biofilm formation by L. gasseri and L. rhamnosus was increased by 2-log (P < 0.001), while biofilms by L. fermentum reduced by >1-log (P < 0.001). L. casei enhanced biofilm formation by ~2-log when grown with S. mutans wild-type, but no such effects were observed with S. mutans deficient of glucosyltransferase GtfB and adhesin P1. Both S. mutans and L. casei in dual-species enhanced resistance to acid killing with increases of survival rate by >1-log (P < 0.001), but drastically reduced the survival rates following exposure to hydrogen peroxide (P < 0.001), as compared to the respective mono-species cultures. When analyzed by RNA-seq, more than 134 genes were identified in S. mutans in dual-species with L. casei as either up- or down-regulated when compared to those grown alone. The up-regulated genes include those for superoxide dismutase, NADH oxidase, and members of the mutanobactin biosynthesis cluster. Among the down-regulated genes were those for GtfB and alternative sigma factor SigX. These results further suggest that interactions between S. mutans and oral lactobacilli are species-specific and may have significant impact on cariogenic potential of the community.}, } @article {pmid29326225, year = {2018}, author = {Suryaletha, K and Narendrakumar, L and John, J and Reghunathan, D and Prasannakumar, M and Thomas, S}, title = {Genomic Insights into Biofilm-Forming Enterococcus faecalis SK460 Isolated from a Chronic Diabetic Ulcer Patient.}, journal = {Genome announcements}, volume = {6}, number = {2}, pages = {}, pmid = {29326225}, issn = {2169-8287}, abstract = {Enterococcus faecalis is recognized as one of the leading pathogens causing nosocomial infections. Here we report a draft genome sequence of Enterococcus faecalis SK460, isolated from a chronic diabetic foot ulcer patient. This strain exhibits various biofilm-associated genes, virulence genes, and antibiotic-resistance genes related to aminoglycoside, macrolide, and tetracycline resistance.}, } @article {pmid29325080, year = {2018}, author = {Lu, JJ and Lo, HJ and Wu, YM and Chang, JY and Chen, YZ and Wang, SH}, title = {DST659 genotype of Candida albicans showing positive association between biofilm formation and dominance in Taiwan.}, journal = {Medical mycology}, volume = {56}, number = {8}, pages = {972-978}, doi = {10.1093/mmy/myx151}, pmid = {29325080}, issn = {1460-2709}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/classification/genetics/*isolation & purification/*physiology ; Candidemia/*epidemiology/*microbiology/mortality ; Disease Models, Animal ; Female ; *Genotype ; Humans ; Incidence ; Male ; Multilocus Sequence Typing ; Retrospective Studies ; Survival Analysis ; Taiwan/epidemiology ; Virulence ; Zebrafish/microbiology ; Zygote/microbiology ; }, abstract = {Based on multiple locus sequence typing, we previously found that DST659 and DST693 were dominant genotypes of Candida albicans among the bloodstream isolates at Chang-Gung Memorial Hospital at Linkou. Biofilm-forming activity, which is critical for C. albicans virulence, probably contributed to the dominance of antifungal sensitive isolates in hospital. Both in vitro membrane weighting and in vivo zebrafish egg infection assays were used to evaluate the biofilm-forming activity of DST659 and DST693 genotypes. Medical records of the patients infected by these two genotypes were retrospectively reviewed. High biofilm-forming activity of DST659 isolates was demonstrated in vitro and further proved with the zebrafish egg infection model, which showed a positive correlation between the biofilm-forming extent on chorion and the in vitro biofilm activity. Moreover, significantly less embryos survived when infected with DST659 isolates than those with DST693 (1.25% vs. 11.43%), and the high-biofilm subset of DST659 showed a greater reduction in survival of embryos at 48 h post-infection than the low-biofilm subset (0 vs. 1.92%). Patients infected with DST659 seemed to survive slightly worse than those infected with DST693, although the difference was insignificant. It is noteworthy that DST659-infected patients were associated with a higher incidence in renal insufficiency as compared to those with DST693, the low biofilm genotype. We suggest that a strong biofilm activity of DST659 contributed to a high mortality rate in zebrafish hosts and poor renal function in patients, as well as gaining the dominance in the northern Taiwan.}, } @article {pmid29324361, year = {2018}, author = {Derakhshan, Z and Mahvi, AH and Ghaneian, MT and Mazloomi, SM and Faramarzian, M and Dehghani, M and Fallahzadeh, H and Yousefinejad, S and Berizi, E and Ehrampoush, MH and Bahrami, S}, title = {Simultaneous removal of atrazine and organic matter from wastewater using anaerobic moving bed biofilm reactor: A performance analysis.}, journal = {Journal of environmental management}, volume = {209}, number = {}, pages = {515-524}, doi = {10.1016/j.jenvman.2017.12.081}, pmid = {29324361}, issn = {1095-8630}, mesh = {Atrazine/*isolation & purification ; Biofilms ; *Bioreactors ; Waste Disposal, Fluid ; *Wastewater ; Water Purification ; }, abstract = {In this study, an anaerobic moving bed biofilm reactor (AMBBR) was designed to biodegrade atrazine under mesophilic (32 °C) condition and then it was evaluated for approximately 1 year. After biofilm formation, acclimation, and enrichment of microbial population within the bioreactor, the effect of various operation conditions such as changes in the concentration of influent atrazine and sucrose, hydraulic retention time (HRT), and salinity on the removal of atrazine and chemical oxygen demand (COD) were studied. In optimum conditions, the maximum removal efficiency of atrazine and COD was 60.5% and 97.4%, respectively. Various models were developed to predict the performance of atrazine removal as a function of HRT during continuous digestion. Also, coefficients kinetics was studied and the maximum atrazine removal rate was determined by Stover - Kincannon model (rmax = 0.223 kgATZ/m[3]d). Increasing salinity up to 20 g/L NaCl in influent flow could inhibit atrazine biodegradation process strongly in the AMBBR reactor; whereas, the reactor could tolerate the concentrations less than 20 g/L easily. Results showed that AMBBR is feasible, easy, affordable, so suitable process for efficiently biodegrading toxic chlorinated organic compounds such as atrazine. There was no accumulation of atrazine in the biofilm and the loss of atrazine in the control reactor was negligible; this shows that atrazine removal mechanism in this system was due to co-metabolism.}, } @article {pmid29324344, year = {2018}, author = {Li, S and Chen, S and Fan, J and Cao, Z and Ouyang, W and Tong, N and Hu, X and Hu, J and Li, P and Feng, Z and Huang, X and Li, Y and Xie, M and He, R and Jian, J and Wu, B and Xu, C and Wu, W and Guo, J and Lin, J and Sun, P}, title = {Anti-biofilm effect of novel thiazole acid analogs against Pseudomonas aeruginosa through IQS pathways.}, journal = {European journal of medicinal chemistry}, volume = {145}, number = {}, pages = {64-73}, doi = {10.1016/j.ejmech.2017.12.076}, pmid = {29324344}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Structure-Activity Relationship ; Thiazoles/chemical synthesis/chemistry/*pharmacology ; }, abstract = {IQS has been proven to be a new quorum sensing (QS) system against bacterial biofilm formation, which is activated in the common phosphate-limiting environment of infected tissues taking over the central las system. Up to now, numerous biofilm inhibitors which function by affecting traditional QS system have been reported. However, no compound has been reported to exert anti-biofilm activity through IQS system. Herein, various novel IQS derivatives were synthesized by the reaction of thiazole-4-carboxylic acid with different linear alcohols (R-OH) or amines (R-NH2). IQS derivatives with four carbon chain length of R group were found to present the best biofilm inhibition activity. Compound B-11 as the model molecule was observed to inhibit biofilm formation only under phosphate-limiting condition, and increase in B-11 concentration significantly reduced the expression of rhlA-gfp and pqsA-gfp, but lasB-gfp. Moreover, B-11 reduced production of virulence factors of rhamnolipid and pyocyanin under phosphate limitation. These observations indicated that the synthesized compounds possessed the anti-biofilm activity through IQS pathways rather than traditional QS pathways, which pave a path for future molecular design against bacterial biofilm formation.}, } @article {pmid29323250, year = {2018}, author = {Batchelor, MT and Burne, RV and Henry, BI and Li, F and Paul, J}, title = {A biofilm and organomineralisation model for the growth and limiting size of ooids.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {559}, pmid = {29323250}, issn = {2045-2322}, mesh = {*Biofilms ; Geologic Sediments/*chemistry/microbiology ; Minerals/chemistry ; *Models, Theoretical ; }, abstract = {Ooids are typically spherical sediment grains characterised by concentric layers encapsulating a core. There is no universally accepted explanation for ooid genesis, though factors such as agitation, abiotic and/or microbial mineralisation and size limitation have been variously invoked. Here we examine the possible influence of microbial organomineralisation on the formation of some naturally occurring ooids. We develop a mathematical model for ooid growth, inspired by work on avascular brain tumours, that assumes mineralisation in a biofilm to form a central core which then nucleates the progressive growth of concentric laminations. The model predicts a limiting size with the sequential width variation of growth rings comparing favourably with those observed in experimentally grown ooids generated from biomicrospheres. In reality, this model pattern may be complicated during growth by syngenetic aggrading neomorphism of the unstable mineral phase, followed by diagenetic recrystallisation that further complicates the structure. Our model provides a potential key to understanding the genetic archive preserved in the internal structures of some ooids.}, } @article {pmid29322006, year = {2018}, author = {Sankar Ganesh, P and Ravishankar Rai, V}, title = {Attenuation of quorum-sensing-dependent virulence factors and biofilm formation by medicinal plants against antibiotic resistant Pseudomonas aeruginosa.}, journal = {Journal of traditional and complementary medicine}, volume = {8}, number = {1}, pages = {170-177}, pmid = {29322006}, issn = {2225-4110}, abstract = {Pseudomonas aeruginosa use small signaling molecules such as acyl homoserine lactones (AHLs), which play an important role in release virulence factors and toxin for further establishment of host infection. Thus, involving with the QS system would provide alternative ways of preventing the pathogenicity. In the present study, totally six medicinal plants (Terminalia bellerica, Celastrus paniculatus, Kingiodendron pinnatum, Schleichera oleosa, Melastoma malabathricum, Garcinia gummi-gutta) were screened for anti-QS activity using biomonitor strain of Chromobacterium violaceum CV12472. The primary screening of antimicrobial activity of all the plant extracts have inhibited the growth of tested bacterial species. Of these at the sub-minimum inhibitory concentration the methanol extract of T. bellerica (0.0625-0.5 mg/ml) has significantly inhibited violacein production (20.07-66.22%) in C. violaceum (CV12472). Consequently, the extract of T. bellerica has reduced the production of pyocyanin, exopolysaccharide and biofilm formation in P. aeruginosa strains. Fluorescence and scanning electron microscopy analysis confirmed the reduction of biofilm formation in P. aeruginosa strains when treated with T. bellerica. GC-MS analysis showed the active compounds inhibited the production of virulence factors of P. aeruginosa. The results suggest the possible use of this T. bellerica as an anti-QS and anti-biofilm agent to control Pseudomonas infection. Interference of QS provides an important means for the inhibition of bacterial virulence and thus aids in treatment strategies.}, } @article {pmid29320565, year = {2018}, author = {Brauge, T and Faille, C and Sadovskaya, I and Charbit, A and Benezech, T and Shen, Y and Loessner, MJ and Bautista, JR and Midelet-Bourdin, G}, title = {The absence of N-acetylglucosamine in wall teichoic acids of Listeria monocytogenes modifies biofilm architecture and tolerance to rinsing and cleaning procedures.}, journal = {PloS one}, volume = {13}, number = {1}, pages = {e0190879}, pmid = {29320565}, issn = {1932-6203}, mesh = {Acetylglucosamine/*metabolism ; Bacterial Adhesion/genetics/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cell Wall/genetics/*metabolism/ultrastructure ; Hydrophobic and Hydrophilic Interactions ; Listeria monocytogenes/genetics/*physiology/ultrastructure ; Microscopy, Electron, Transmission ; Mutation ; Phenotype ; Stainless Steel ; Stress, Mechanical ; Teichoic Acids/*metabolism ; Water ; }, abstract = {The wall teichoic acid (WTA) is the major carbohydrate found within the extracellular matrix of the Listeria monocytogenes biofilm. We first addressed the frequency of spontaneous mutations in two genes (lmo2549 and lmo2550) responsible for the GlcNAcylation in 93 serotype 1/2a strains that were mainly isolated from seafood industries. We studied the impact of mutations in lmo2549 or lmo2550 genes on biofilm formation by using one mutant carrying a natural mutation inactivating the lmo2550 gene (DSS 1130 BFA2 strain) and two EGD-e mutants that lack respective genes by in-frame deletion of lmo2549 or lmo2550 using splicing-by-overlap-extension PCR, followed by allelic exchange mutagenesis. The lmo2550 gene mutation, occurring in around 50% isolates, caused a decrease in bacterial adhesion to stainless steel compared to wild-type EGD-e strain during the adhesion step. On the other hand, bacterial population weren't significantly different after 24h-biofilm formation. The biofilm architecture was different between the wild-type strain and the two mutants inactivated for lmo2549 or lmo2550 genes respectively with the presence of bacterial micro-colonies for mutants which were not observed in the wild-type EGD-e strain biofilm. These differences might account for the stronger hydrophilic surface exhibited by the mutant cells. Upon a water flow or to a cleaning procedure at a shear stress of 0.16 Pa, the mutant biofilms showed the higher detachment rate compared to wild-type strain. Meanwhile, an increase in the amount of residual viable but non-culturable population on stainless steel was recorded in two mutants. Our data suggests that the GlcNAc residue of WTA played a role in adhesion and biofilm formation of Listeria monocyctogenes.}, } @article {pmid29320462, year = {2018}, author = {Nicol, M and Alexandre, S and Luizet, JB and Skogman, M and Jouenne, T and Salcedo, SP and Dé, E}, title = {Unsaturated Fatty Acids Affect Quorum Sensing Communication System and Inhibit Motility and Biofilm Formation of Acinetobacter baumannii.}, journal = {International journal of molecular sciences}, volume = {19}, number = {1}, pages = {}, pmid = {29320462}, issn = {1422-0067}, mesh = {Acinetobacter baumannii/*physiology ; Acyl-Butyrolactones/metabolism ; Biofilms/*drug effects ; Fatty Acids, Monounsaturated/pharmacology ; Fatty Acids, Unsaturated/*pharmacology ; Microscopy, Atomic Force ; Quorum Sensing/*drug effects ; }, abstract = {The increasing threat of Acinetobacter baumannii as a nosocomial pathogen is mainly due to the occurrence of multidrug-resistant strains that are associated with the real problem of its eradication from hospital wards. The particular ability of this pathogen to form biofilms contributes to its persistence, increases antibiotic resistance, and promotes persistent/device-related infections. We previously demonstrated that virstatin, which is a small organic compound known to decrease virulence of Vibrio cholera via an inhibition of T4-pili expression, displayed very promising activity to prevent A. baumannii biofilm development. Here, we examined the antibiofilm activity of mono-unsaturated chain fatty acids, palmitoleic (PoA), and myristoleic (MoA) acids, presenting similar action on V. cholerae virulence. We demonstrated that PoA and MoA (at 0.02 mg/mL) were able to decrease A. baumannii ATCC 17978 biofilm formation up to 38% and 24%, respectively, presented a biofilm dispersing effect and drastically reduced motility. We highlighted that these fatty acids decreased the expression of the regulator abaR from the LuxIR-type quorum sensing (QS) communication system AbaIR and consequently reduced the N-acyl-homoserine lactone production (AHL). This effect can be countered by addition of exogenous AHLs. Besides, fatty acids may have additional non-targeted effects, independent from QS. Atomic force microscopy experiments probed indeed that PoA and MoA could also act on the initial adhesion process in modifying the material interface properties. Evaluation of fatty acids effect on 22 clinical isolates showed a strain-dependent antibiofilm activity, which was not correlated to hydrophobicity or pellicle formation ability of the tested strains, and suggested a real diversity in cell-to-cell communication systems involved in A. baumannii biofilm formation.}, } @article {pmid29319523, year = {2017}, author = {Biočanin, M and Madi, H and Vasiljević, Z and Kojić, M and Jovčić, B and Lozo, J}, title = {Temperature, pH and Trimethoprim-Sulfamethoxazole Are Potent Inhibitors of Biofilm Formation by Stenotrophomonas maltophilia Clinical Isolates.}, journal = {Polish journal of microbiology}, volume = {66}, number = {4}, pages = {433-438}, doi = {10.5604/01.3001.0010.6996}, pmid = {29319523}, issn = {1733-1331}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cross Infection/microbiology ; Cystic Fibrosis/microbiology ; Gram-Negative Bacterial Infections/drug therapy ; Hospitals, Pediatric ; Humans ; Hydrogen-Ion Concentration ; Microbial Sensitivity Tests ; Serbia ; Stenotrophomonas maltophilia/*drug effects ; *Temperature ; Trimethoprim, Sulfamethoxazole Drug Combination/*pharmacology ; }, abstract = {Stenotrophomonas maltophilia, an opportunistic pathogen usually connected with healthcare-associated infections, is an environmental bacterium. Intrinsic resistance to multiple antibiotics, with different virulence determinants in the last decade classified this bacterium in the group of global multiple drug resistant (MDR) organism. S. maltophilia clinical isolates, were collected from tertiary care pediatric hospital in Belgrade, Serbia to investigate influence of different factors on biofilm formation, kinetics of biofilm formation for strong biofilm producers and effect of trimethoprim-sulfamethoxazole (TMP/SMX) on formed biofilm. Most of the isolates (89.8%) were able to form a biofilm. Analysis of biofilm formation in different growth conditions showed that changing of temeperature and pH had the stronggest effect on biofilm formation almost equally in group of cystic fibrosis (CF) and non-CF strains. TMP/SMX in concentration of 50 μg/ml reduced completely 24 h old biofilms while concentration of 25 μg/ml effects formed biofilms in a strain dependent manner. Among strains able to form strong biofilm CF isolates formed biofilm slower than non-CF isolates, while shaking conditions did not affect biofilm formation. Swimming motility was detected in both CF and non-CF isolates, however more motile strain formed stronger biofilms. This study suggests that temperature, pH and TMP/SMX had the strongest influence on biofilm formation in analyzed collection of S. maltophilia. A positive correlation between motility and strength of formed biofilm was demonstrated.}, } @article {pmid29319515, year = {2017}, author = {Shah, RK and Ni, ZH and Sun, XY and Wang, GQ and Li, F}, title = {The Determination and Correlation of Various Virulence Genes, ESBL, Serum Bactericidal Effect and Biofilm Formation of Clinical Isolated Classical Klebsiella pneumoniae and Hypervirulent Klebsiella pneumoniae from Respiratory Tract Infected Patients.}, journal = {Polish journal of microbiology}, volume = {66}, number = {4}, pages = {501-508}, doi = {10.5604/01.3001.0010.7042}, pmid = {29319515}, issn = {1733-1331}, mesh = {Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Bacteremia/microbiology ; Biofilms/*growth & development ; Blood Bactericidal Activity ; Female ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/drug effects/*pathogenicity ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Polymerase Chain Reaction ; Respiratory System/*microbiology ; Sputum/microbiology ; Virulence Factors/*genetics ; beta-Lactamases/genetics ; }, abstract = {Klebsiella pneumoniae strains that are commonly recognized by clinicians and microbiologists are termed as classical K. pneumoniae (cKP). A strain with capsule-associated mucopolysaccharide web is known as hypervirulent K. pneumoniae (hvKP) as it enhances the serum resistant and biofilm production. Aim is to determine and correlate various virulence genes, ESBL, serum bactericidal effect and biofilm formation of clinical isolated cKP and hvKP from respiratory tract infected patients. A total of 96 K. pneumoniae strains were isolated from sputum of respiratory tract infected patients. The isolates were performed string test, AST, ESBL virulence gene, serum bactericidal and biofilm assays. Out of 96 isolates, 39 isolates (40.6%) were identified with hypervirulent phenotypes. The number of cKP exhibiting resistance to the tested antimicrobials and ESBLs were significantly higher than that of the hvKP strains. The virulence genes of K. pneumoniae such as K1, K2, rmpA, uge, kfu and aerobactin were strongly associated with hvKP than cKP. However, no significant difference was found in FIM-1 and MrKD3 genes. ESBL producing cKP and hvKP were significantly associated with strong biofilm formation (both P < 0.05) and highly associated with bactericidal effect of serum (both P < 0.05) than cKP strains. However, neither biofilm formation nor bactericidal effect of serum was found with significant difference in between ESBL producing cKP and ESBL producing hvKP strains (both P > 0.05). Although the hvKP possess more virulence gene, but they didn't show any significant difference between biofilm formation and bactericidal effect of serum compared with ESBL producing cKP strains.}, } @article {pmid29319410, year = {2019}, author = {Jiang, X and Xu, B and Wu, J}, title = {Sulfur recovery in the sulfide-oxidizing membrane aerated biofilm reactor: experimental investigation and model simulation.}, journal = {Environmental technology}, volume = {40}, number = {12}, pages = {1557-1567}, doi = {10.1080/09593330.2018.1426638}, pmid = {29319410}, issn = {1479-487X}, mesh = {Biofilms ; *Bioreactors ; Oxidation-Reduction ; Sulfides ; *Sulfur ; }, abstract = {The production of sulfur (S) from the biological oxidization of sulfide (S[2-]) by SOB (sulfide-oxidizing bacteria) allows for resource recovery. Past researches have indicated that S recovery from S[2-] oxidation MABR (the membrane aerated biofilm reactor) was feasible. The process was complicated by the requirement of maintaining appropriate oxygen supply to prevent the produced S from being further oxidized into sulfate (SO42-) and by the presence of heterotrophic biomass. In this study, a multispecies biofilm model was developed and experimentally validated to gain insight for the S recovery process in MABR. The developed model was capable of predicting the S recovery performance in the MABR. The optimal conditions involved in maintaining the appropriate oxygen flux and the biofilm thickness according to the hydraulic and S[2-] loading rate. The low anoxic heterotrophic growth rate using SO42- and S as electron donors could explain why the impact of heterotrophic growth was insignificant.}, } @article {pmid29319346, year = {2018}, author = {Favre, L and Ortalo-Magné, A and Pichereaux, C and Gargaros, A and Burlet-Schiltz, O and Cotelle, V and Culioli, G}, title = {Metabolome and proteome changes between biofilm and planktonic phenotypes of the marine bacterium Pseudoalteromonas lipolytica TC8.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {132-148}, doi = {10.1080/08927014.2017.1413551}, pmid = {29319346}, issn = {1029-2454}, mesh = {Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Biofouling/*prevention & control ; Chromatography, Liquid ; Metabolome/*physiology ; Metabolomics/methods ; Phenotype ; Plankton/growth & development/*metabolism ; Proteome/*metabolism ; Proteomics/methods ; Pseudoalteromonas/growth & development/*metabolism ; Tandem Mass Spectrometry ; }, abstract = {A number of bacteria adopt various lifestyles such as planktonic free-living or sessile biofilm stages. This enables their survival and development in a wide range of contrasting environments. With the aim of highlighting specific metabolic shifts between these phenotypes and to improve the overall understanding of marine bacterial adhesion, a dual metabolomics/proteomics approach was applied to planktonic and biofilm cultures of the marine bacterium Pseudoalteromonas lipolytica TC8. The liquid chromatography mass spectrometry (LC-MS) based metabolomics study indicated that membrane lipid composition was highly affected by the culture mode: phosphatidylethanolamine (PEs) derivatives were over-produced in sessile cultures while ornithine lipids (OLs) were more specifically synthesized in planktonic samples. In parallel, differences between proteomes revealed that peptidases, oxidases, transcription factors, membrane proteins and the enzymes involved in histidine biosynthesis were over-expressed in biofilms while proteins involved in heme production, nutrient assimilation, cell division and arginine/ornithine biosynthesis were specifically up-regulated in free-living cells.}, } @article {pmid29318813, year = {2018}, author = {Lee, ES and de Josselin de Jong, E and Jung, HI and Kim, BI}, title = {Red fluorescence of dental biofilm as an indicator for assessing the efficacy of antimicrobials.}, journal = {Journal of biomedical optics}, volume = {23}, number = {1}, pages = {1-6}, doi = {10.1117/1.JBO.23.1.015003}, pmid = {29318813}, issn = {1560-2281}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cattle ; Chlorhexidine/pharmacology ; Dental Caries/*microbiology ; Dental Enamel/microbiology ; Humans ; Models, Biological ; Saliva/microbiology ; Spectrometry, Fluorescence/*methods ; }, abstract = {The study aimed to determine whether the red fluorescence (RF) of a dental microcosm biofilm as measured with quantitative light-induced fluorescence (QLF) technology is useful for assessing the efficacy of antimicrobials. Dental microcosm biofilms were formed on bovine enamel discs and grown under 0.3% sucrose challenge and treated with chlorhexidine (CHX) solutions at different concentrations (0.05%, 0.1%, and 0.5%) plus a negative control [sterile distilled water (DW)] twice daily for 7 days. The biofilms were photographed using a QLF-digital system to evaluate the RF by calculating the red/green ratio, and pH values of the medium were measured daily. After 7 days, the bacterial viability of the biofilm was assessed by measuring the counts of viable total bacteria and aciduric bacteria, and the percentage surface microhardness changes (%SHC) was evaluated. The RF and cariogenic properties were compared for the different concentrations of CHX, and their correlations were examined. The RF and its increase rate were much lower for CHX-treated biofilms than for DW-treated biofilms. The RF after 7 days of maturation decreased significantly with increasing CHX concentrations (p<0.001) and was from 31% (for 0.05% CHX) to 46% (for 0.5% CHX) lower than that of the DW group. Strong correlations were reported between the RF of the 7-day-maturation biofilms and cariogenic properties, such as the number of total bacteria (r=0.93), number of aciduric bacteria (r=0.97), supernatant pH (r=0.43), and %SHC (r=0.98). In conclusion, the RF of dental biofilms as measured with QLF technology can be used to nondestructively assess and monitor the effect of antimicrobials against biofilm.}, } @article {pmid29318048, year = {2017}, author = {Pakshir, K and Bordbar, M and Zomorodian, K and Nouraei, H and Khodadadi, H}, title = {Evaluation of CAMP-Like Effect, Biofilm Formation, and Discrimination of Candida africana from Vaginal Candida albicans Species.}, journal = {Journal of pathogens}, volume = {2017}, number = {}, pages = {7126258}, pmid = {29318048}, issn = {2090-3057}, abstract = {Candida africana as a species recovered from female genital specimens is highly close to C. albicans. The present study was conducted to discriminate C. africana from presumptive vaginal C. albicans strains by molecular assay and evaluate their hemolysin activity, biofilm formation, and cohemolytic effect (CAMP) with vaginal bacterial flora. A total of 110 stock vaginal C. albicans isolates were examined by HWP1 gene amplification. Hemolysin activity and the ability of biofilm formation were evaluated by blood plate assay and visual detection methods, respectively. Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae were used to evaluate the CAMP-like effects in Sabouraud blood agar media. Based on the size of the amplicons (941 bp), all isolates were identified as C. albicans. All samples were able to produce beta-hemolysin. Moreover, 69 out of 110 of the isolates (62.7%) were biofilm-positive, 54 out of 110 Candida isolates (49%) demonstrated cohemolytic effects with S. agalactiae, and 48 out of 110 showed this effect with S. aureus (43.6%). All isolates were CAMP-negative with S. epidermidis. We detected all isolates as Candida albicans and almost half of the isolates were CAMP-positive with S. aureus and S. agalactiae, suggesting that these bacteria increase the pathogenicity of Candida in vaginal candidiasis.}, } @article {pmid29317719, year = {2018}, author = {Junka, AF and Rakoczy, R and Szymczyk, P and Bartoszewicz, M and Sedghizadeh, PP and Fijałkowski, K}, title = {Application of Rotating Magnetic Fields Increase the Activity of Antimicrobials Against Wound Biofilm Pathogens.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {167}, pmid = {29317719}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Biomass ; Cell Survival/drug effects ; Fibroblasts ; Humans ; *Magnetic Fields ; }, abstract = {Infective complications are a major factor contributing to wound chronicity and can be associated with significant morbidity or mortality. Wound bacteria are protected in biofilm communities and are highly resistant to immune system components and to antimicrobials used in wound therapy. There is an urgent medical need to more effectively eradicate wound biofilm pathogens. In the present work, we tested the impact of such commonly used antibiotics and antiseptics as gentamycin, ciprofloxacin, octenidine, chlorhexidine, polihexanidine, and ethacridine lactate delivered to Staphylococcus aureus and Pseudomonas aeruginosa biofilms in the presence of rotating magnetic fields (RMFs) of 10-50 Hz frequency and produced by a customized RMF generator. Fifty percent greater reduction in biofilm growth and biomass was observed after exposure to RMF as compared to biofilms not exposed to RMF. Our results suggest that RMF as an adjunct to antiseptic wound care can significantly improve antibiofilm activity, which has important translational potential for clinical applications.}, } @article {pmid29317704, year = {2018}, author = {González, JF and Alberts, H and Lee, J and Doolittle, L and Gunn, JS}, title = {Biofilm Formation Protects Salmonella from the Antibiotic Ciprofloxacin In Vitro and In Vivo in the Mouse Model of chronic Carriage.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {222}, pmid = {29317704}, issn = {2045-2322}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; R56 AI109002/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology/therapeutic use ; *Drug Resistance, Bacterial ; Gallstones/microbiology ; Mice ; Salmonella Infections/drug therapy/*microbiology ; Salmonella typhimurium/drug effects/*physiology ; }, abstract = {Typhoid fever is caused by the human-restricted pathogen Salmonella enterica sv. Typhi. Approximately 5% of people that resolve the disease become chronic carriers, with the gallbladder as the main reservoir of the bacteria. Of these, about 90% present with gallstones, on which Salmonella form biofilms. Because S. Typhi is a human-restricted pathogen, these carriers are the main source of dissemination of the disease; unfortunately, antibiotic treatment has shown to be an ineffective therapy. This is believed to be caused by the inherent antibiotic resistance conferred by Salmonella biofilms growing on gallstones. The gallstone mouse model with S. Typhimurium has proven to be an excellent surrogate for S. Typhi chronic infection. In this study, we test the hypothesis that the biofilm state confers Salmonella with the increased resistance to antibiotics observed in cases of chronic carriage. We found that, in the biofilm state, Salmonella is significantly more resistant to ciprofloxacin, a common antibiotic used for the treatment of Salmonella, both in vitro (p < 0.001 for both S. Typhi and S. Typhimurium with respect to planktonic cells) and in vivo (p = 0.0035 with respect to control mice).}, } @article {pmid29317687, year = {2018}, author = {Hu, J and Zhang, N and Li, L and Zhang, N and Ma, Y and Zhao, C and Wu, Q and Li, Y and He, N and Wang, X}, title = {The synergistic bactericidal effect of vancomycin on UTMD treated biofilm involves damage to bacterial cells and enhancement of metabolic activities.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {192}, pmid = {29317687}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/radiation effects ; Cell Membrane/drug effects/radiation effects ; Disinfection/*methods ; Sonication/methods ; Staphylococcus epidermidis/*drug effects/radiation effects/ultrastructure ; *Ultrasonic Waves ; Vancomycin/*pharmacology ; }, abstract = {In this study, the synergistic effect of vancomycin, a cell wall synthesis inhibitor, and ultrasound-targeted microbubble destruction (UTMD), on cell viability of Staphylococcus epidermidis, embedded in biofilm, was investigated. Biofilms are the leading causes of antibiotic-resistant bacterial infections of medical implants and prosthetics worldwide. The antibiotic-resistant nature of biofilm-embedded pathogens poses a critical challenge to the medical community. Previously, studies have demonstrated the efficacy of using ultrasound waves and UTMD in circumventing this problem. However, the mechanism(s) underlying this phenomenon was not clear. Here, the present study showed that both ultrasound and UTMD damaged the cell wall structure of S. epidermidis, and floccules and fragments from damaged cells were observed on transmission electron microscope micrograph. However, the cell membrane integrity was not seriously affected by treatments, and the treatment increased the metabolic activity levels of the dormant biofilm-embedded bacteria, detected by confocal laser scanning microscope and flow cytometry, which could make them susceptible to the effect of the antibiotic. Thus, the biological mechanism underlying the efficacy of the combined treatment involving UTMD and vancomycin in the case of S. epidermidis biofilm was dissected, which may be utilized for further investigations on other biofilm pathogens before clinical use.}, } @article {pmid29317512, year = {2018}, author = {Reddinger, RM and Luke-Marshall, NR and Sauberan, SL and Hakansson, AP and Campagnari, AA}, title = {Streptococcus pneumoniae Modulates Staphylococcus aureus Biofilm Dispersion and the Transition from Colonization to Invasive Disease.}, journal = {mBio}, volume = {9}, number = {1}, pages = {}, pmid = {29317512}, issn = {2150-7511}, support = {R01 DC013554/DC/NIDCD NIH HHS/United States ; R01 DC014576/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; *Antibiosis ; Biofilms/*growth & development ; Carrier State/*microbiology ; Coinfection/microbiology ; Disease Models, Animal ; Epithelial Cells/microbiology ; Mice ; Pneumococcal Infections/*complications/microbiology ; Pneumonia, Bacterial/microbiology ; Staphylococcal Infections/microbiology/*prevention & control ; Staphylococcus aureus/*growth & development ; Streptococcus pneumoniae/*growth & development ; }, abstract = {Streptococcus pneumoniae and Staphylococcus aureus are ubiquitous upper respiratory opportunistic pathogens. Individually, these Gram-positive microbes are two of the most common causative agents of secondary bacterial pneumonia following influenza A virus infection, and they constitute a significant source of morbidity and mortality. Since the introduction of the pneumococcal conjugate vaccine, rates of cocolonization with both of these bacterial species have increased, despite the traditional view that they are antagonistic and mutually exclusive. The interactions between S. pneumoniae and S. aureus in the context of colonization and the transition to invasive disease have not been characterized. In this report, we show that S. pneumoniae and S. aureus form stable dual-species biofilms on epithelial cells in vitro When these biofilms are exposed to physiological changes associated with viral infection, S. pneumoniae disperses from the biofilm, whereas S. aureus dispersal is inhibited. These findings were supported by results of an in vivo study in which we used a novel mouse cocolonization model. In these experiments, mice cocolonized in the nares with both bacterial species were subsequently infected with influenza A virus. The coinfected mice almost exclusively developed pneumococcal pneumonia. These results indicate that despite our previous report that S. aureus disseminates into the lungs of mice stably colonized with these bacteria following influenza A virus infection, cocolonization with S. pneumoniae in vitro and in vivo inhibits S. aureus dispersal and transition to disease. This study provides novel insight into both the interactions between S. pneumoniae and S. aureus during carriage and the transition from colonization to secondary bacterial pneumonia.IMPORTANCE In this study, we demonstrate that Streptococcus pneumoniae can modulate the pathogenic potential of Staphylococcus aureus in a model of secondary bacterial pneumonia. We report that host physiological signals related to viral infection cease to elicit a dispersal response from S. aureus while in a dual-species setting with S. pneumoniae, in direct contrast to results of previous studies with each species individually. This study underscores the importance of studying polymicrobial communities and their implications in disease states.}, } @article {pmid29316701, year = {2018}, author = {Mao, Y and Singh-Varma, A and Hoffman, T and Dhall, S and Danilkovitch, A and Kohn, J}, title = {The Effect of Cryopreserved Human Placental Tissues on Biofilm Formation of Wound-Associated Pathogens.}, journal = {Journal of functional biomaterials}, volume = {9}, number = {1}, pages = {}, pmid = {29316701}, issn = {2079-4983}, abstract = {Biofilm, a community of bacteria, is tolerant to antimicrobial agents and ubiquitous in chronic wounds. In a chronic DFU (Diabetic Foot Ulcers) clinical trial, the use of a human cryopreserved viable amniotic membrane (CVAM) resulted in a high rate of wound closure and reduction of wound-related infections. Our previous study demonstrated that CVAM possesses intrinsic antimicrobial activity against a spectrum of wound-associated bacteria under planktonic culture conditions. In this study, we evaluated the effect of CVAM and cryopreserved viable umbilical tissue (CVUT) on biofilm formation of S. aureus and P. aeruginosa, the two most prominent pathogens associated with chronic wounds. Firstly, we showed that, like CVAM, CVUT released antibacterial activity against multiple bacterial pathogens and the devitalization of CVUT reduced its antibacterial activity. The biofilm formation was then measured using a high throughput method and an ex vivo porcine dermal tissue model. We demonstrate that the formation of biofilm was significantly reduced in the presence of CVAM- or CVUT-derived conditioned media compared to control assay medium. The formation of P. aeruginosa biofilm on CVAM-conditioned medium saturated porcine dermal tissues was reduced 97% compared with the biofilm formation on the control medium saturated dermal tissues. The formation of S. auerus biofilm on CVUT-conditioned medium saturated dermal tissues was reduced 72% compared with the biofilm formation on the control tissues. This study is the first to show that human cryopreserved viable placental tissues release factors that inhibit biofilm formation. Our results provide an explanation for the in vivo observation of their ability to support wound healing.}, } @article {pmid29316499, year = {2018}, author = {Jiang, X and Ying, D and Ye, D and Zhang, R and Guo, Q and Wang, Y and Jia, J}, title = {Electrochemical study of enhanced nitrate removal in wastewater treatment using biofilm electrode.}, journal = {Bioresource technology}, volume = {252}, number = {}, pages = {134-142}, doi = {10.1016/j.biortech.2017.12.078}, pmid = {29316499}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Denitrification ; Electrodes ; Nitrates ; Nitrogen ; *Wastewater ; }, abstract = {Bioelectrochemical enhanced nitrate removal in wastewater with high total nitrogen and low organic carbon was electrochemically investigated focusing on the relationship between biochemical and electrochemical nitrogen cycles. Under optimized external voltage of -0.6 V, apparent nitrate removal rate of bioelectrochemical denitrification was 76% higher than normal biofilm denitrification. And with the introduction of biofilm on the electrode, new reduction peak of N2O, much larger current density, and 0.4 V positively shift of on-set potential of nitrate reduction reaction were observed, suggesting a synergy of electrochemical reaction and biological reaction through enhanced electrochemical reduction of intermediate products from biological process. Oxygen reduction reaction could not be avoided during nitrogen electrochemical reduction reaction since their similar reduction potential. But it led to decrease of oxygen concentration and therefore contribute to biological denitrification. Bacteria community tests also supported a dominant bacteria which could denitrify and use external electron.}, } @article {pmid29316223, year = {2018}, author = {Wasfi, R and Abd El-Rahman, OA and Zafer, MM and Ashour, HM}, title = {Probiotic Lactobacillus sp. inhibit growth, biofilm formation and gene expression of caries-inducing Streptococcus mutans.}, journal = {Journal of cellular and molecular medicine}, volume = {22}, number = {3}, pages = {1972-1983}, pmid = {29316223}, issn = {1582-4934}, mesh = {*Antibiosis ; Bacteriocins/pharmacology ; Biofilms/*drug effects/growth & development ; Catalase/pharmacology ; Culture Media/chemistry ; Humans ; Hydrogen-Ion Concentration ; Interferon-gamma/biosynthesis ; Interleukin-10/biosynthesis ; Lacticaseibacillus casei/drug effects/growth & development/metabolism ; Lactobacillus plantarum/drug effects/growth & development/metabolism ; Limosilactobacillus reuteri/drug effects/growth & development/metabolism ; Ligilactobacillus salivarius/drug effects/*growth & development/metabolism ; Leukocytes, Mononuclear/cytology/immunology/microbiology ; Microbial Sensitivity Tests ; Peroxides/pharmacology ; Polysaccharides, Bacterial/antagonists & inhibitors/biosynthesis ; Primary Cell Culture ; Probiotics/*pharmacology ; Quorum Sensing/drug effects ; Streptococcus mutans/*drug effects/genetics/growth & development/pathogenicity ; Trypsin/pharmacology ; }, abstract = {Streptococcus mutans contributes significantly to dental caries, which arises from homoeostasic imbalance between host and microbiota. We hypothesized that Lactobacillus sp. inhibits growth, biofilm formation and gene expression of Streptococcus mutans. Antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175) were evaluated. We investigated whether Lactobacillus casei (ATCC 393), Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917) or Lactobacillus salivarius (ATCC 11741) inhibit expression of Streptococcus mutans genes involved in biofilm formation, quorum sensing or stress survival using quantitative real-time polymerase chain reaction (qPCR). Growth changes (OD600) in the presence of pH-neutralized, catalase-treated or trypsin-treated Lactobacillus sp. supernatants were assessed to identify roles of organic acids, peroxides and bacteriocin. Susceptibility testing indicated antibacterial (pH-dependent) and antibiofilm activities of Lactobacillus sp. against Streptococcus mutans. Scanning electron microscopy revealed reduction in microcolony formation and exopolysaccharide structural changes. Of the oral normal flora, L. salivarius exhibited the highest antibiofilm and peroxide-dependent antimicrobial activities. All biofilm-forming cells treated with Lactobacillus sp. supernatants showed reduced expression of genes involved in exopolysaccharide production, acid tolerance and quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by limiting growth and virulence properties of Streptococcus mutans.}, } @article {pmid29315379, year = {2018}, author = {Chupácová, J and Borghi, E and Morace, G and Los, A and Bujdáková, H}, title = {Anti-biofilm activity of antibody directed against surface antigen complement receptor 3-related protein-comparison of Candida albicans and Candida dubliniensis.}, journal = {Pathogens and disease}, volume = {76}, number = {1}, pages = {}, doi = {10.1093/femspd/ftx127}, pmid = {29315379}, issn = {2049-632X}, mesh = {Animals ; Antibodies, Fungal/*immunology ; Antigens, Fungal/*immunology ; Antigens, Surface/*immunology ; Biofilms/drug effects/*growth & development ; Biological Assay ; Candida/growth & development/*immunology/*physiology ; Candidiasis/prevention & control ; Cell Adhesion/drug effects ; Disease Models, Animal ; Immunohistochemistry ; Larva/physiology ; Lepidoptera ; Mice ; Receptors, Complement/*immunology ; Survival Analysis ; Tongue/microbiology ; }, abstract = {Candida albicans and C. dubliniensis are related yeasts that differ in the expression of virulence-associated proteins involved in adherence and biofilm development. CR3-RP (complement receptor 3-related protein) is one of the surface antigens expressed by Candida species. The main objective of this research was to elucidate the effect of the polyclonal anti-CR3-RP antibody (Ab) on adherence and the biofilm formed by C. albicans SC5314 and C. dubliniensis CBS 7987 and two clinical isolates in vitro, ex vivo and in vivo. A comparison of species, and of treated vs. non-treated with the anti-CR3-RP Ab showed a reduction in adherence (22%-41%) that was dependent on the time point of evaluation (60, 90 or 120 min), but did not prove to be species-dependent. Confocal microscopy revealed a decreased thickness in biofilms formed by both species after pre-treatment with the anti-CR3-RP Ab. This observation was confirmed ex vivo by immunohistochemistry analysis of biofilms formed on mouse tongues. Moreover, anti-CR3-RP Ab administration, 1 h post-infection, has been shown to promote larval survival compared to the control group in a Galleria mellonella infection model. Our data suggest a potential activity of the anti-CR3-RP Ab relevant to immunotherapy or vaccine development against biofilm-associated Candida infections.}, } @article {pmid29314727, year = {2018}, author = {Albers, P and Weytjens, B and De Mot, R and Marchal, K and Springael, D}, title = {Molecular processes underlying synergistic linuron mineralization in a triple-species bacterial consortium biofilm revealed by differential transcriptomics.}, journal = {MicrobiologyOpen}, volume = {7}, number = {2}, pages = {e00559}, pmid = {29314727}, issn = {2045-8827}, mesh = {Aniline Compounds/*metabolism ; Biodegradation, Environmental ; Biofilms/growth & development ; Comamonadaceae/genetics/*metabolism ; Gene Expression Regulation, Bacterial/genetics ; Herbicides/*metabolism ; Hydrolases/genetics ; Hyphomicrobium/genetics/*metabolism ; Linuron/*metabolism ; Transcriptome/genetics ; Type VI Secretion Systems/genetics ; }, abstract = {The proteobacteria Variovorax sp. WDL1, Comamonas testosteroni WDL7, and Hyphomicrobium sulfonivorans WDL6 compose a triple-species consortium that synergistically degrades and grows on the phenylurea herbicide linuron. To acquire a better insight into the interactions between the consortium members and the underlying molecular mechanisms, we compared the transcriptomes of the key biodegrading strains WDL7 and WDL1 grown as biofilms in either isolation or consortium conditions by differential RNAseq analysis. Differentially expressed pathways and cellular systems were inferred using the network-based algorithm PheNetic. Coculturing affected mainly metabolism in WDL1. Significantly enhanced expression of hylA encoding linuron hydrolase was observed. Moreover, differential expression of several pathways involved in carbohydrate, amino acid, nitrogen, and sulfur metabolism was observed indicating that WDL1 gains carbon and energy from linuron indirectly by consuming excretion products from WDL7 and/or WDL6. Moreover, in consortium conditions, WDL1 showed a pronounced stress response and overexpression of cell to cell interaction systems such as quorum sensing, contact-dependent inhibition, and Type VI secretion. Since the latter two systems can mediate interference competition, it prompts the question if synergistic linuron degradation is the result of true adaptive cooperation or rather a facultative interaction between bacteria that coincidentally occupy complementary metabolic niches.}, } @article {pmid29312828, year = {2018}, author = {Guo, R and Zheng, Y and Liu, H and Li, X and Jia, L and Li, W}, title = {Profiling of subgingival plaque biofilm microbiota in female adult patients with clear aligners: a three-month prospective study.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e4207}, pmid = {29312828}, issn = {2167-8359}, abstract = {BACKGROUND: Clear aligners are well known for facilitating oral hygiene maintenance and decreasing susceptibility to periodontal diseases as compared to conventional fixed appliances. However, few research studies focus on the subgingival microbial community during clear aligner treatment (CAT). Hence, this study investigates changes of the subgingival microbial community and its association with clinical characteristics during the first three months of CAT.

METHODS: Ten female patients with clear aligners were enrolled in this study. Subgingival plaque samples were obtained at three time points: before orthodontic treatment (T0), one month after orthodontic treatment (T1) and three months after orthodontic treatment (T2). DNA was then extracted from plaque samples and analyzed by 16S rRNA gene sequencing. Periodontal examinations, including plaque index (PI) and gingival bleeding index (GBI) measurements were also recorded.

RESULTS: The plaque indices (PIs) and gingival bleeding indices (GBIs) were slightly increased at T1 and T2, but no statistically significant difference was found. The alpha diversity indices, including the ACE, Chao1, Shannon indices, all showed a declining trend without significance, and a rising trend in the Simpson diversity index was observed. The weighted UniFrac distance was significantly higher at T1 and T2 compared with T0. Principal Coordinates Analysis (PCoA) demonstrated that the communities at T0 tended to cluster apart from the communities at T1 and T2. The relative abundance of the phylum Firmicutes and genus Mycoplasma was significantly increased at T0 compared with T2. There was no significant difference in the relative abundance of periodontal pathogens at the genus and species levels or core microorganisms at the genus level.

CONCLUSION: A slightly decreasing microbial diversity with a significant change of microbial structure was found during the first three-month clear aligner treatment (CAT). However, subjects receiving clear aligner treatment were free from periodontal diseases with relatively stable levels of periodontal microorganisms and core microorganisms. Thus, our preliminary findings indicated that clear aligners induced nonpathogenic changes of the subgingival microbiome in the first three-month treatment.}, } @article {pmid29312264, year = {2017}, author = {Pompilio, A and Galardi, G and Verginelli, F and Muzzi, M and Di Giulio, A and Di Bonaventura, G}, title = {Myroides odoratimimus Forms Structurally Complex and Inherently Antibiotic-Resistant Biofilm in a Wound-Like in vitro Model.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2591}, pmid = {29312264}, issn = {1664-302X}, abstract = {Myroides odoratimimus is an aerobic, non-fermenting Gram-negative multidrug-resistant bacterium widely distributed in nature that rarely causes infections in immunocompromised patients. We recently described in a diabetic patient a case of recurrent calcaneal ulcer infection caused by a M. odoratimimus strain showing potential for biofilm formation. For the first time, we therefore evaluated the ability of M. odoratimimus to form biofilm under different pH values and glucose concentrations using an in vitro "skin-like" model, and its susceptibility to levofloxacin, meropenem, and tigecycline. The expression of some antibiotic-resistance related genes was also monitored by RT-PCR during planktonic-to-biofilm transition. Our results indicated that M. odoratimimus can produce relevant amounts of biofilm biomass, in a time-dependent manner, especially at acidic pH and regardless of glucose concentration tested. The comparative analysis of MIC and MBC values between planktonic and sessile cells showed that resistance to antibiotics increased during the planktonic-to-biofilm transition. Viable cell count indicated that none of the tested antibiotics were able to completely eradicate preformed biofilms, although meropenem and levofloxacin were the most active causing a significant, dose-independent, reduction of biofilm's viability, as also confirmed by microscopic analysis. RT-PCR showed that antibiotic-resistance related gyrA and acrB genes are over-expressed during the transition from planktonic to sessile (biofilm) lifestyle. Overall, our findings showed that M. odoratimimus can form relevant amounts of inherently antibiotic-resistant biofilm under conditions relevant to wound site, therefore suggesting a role in the pathogenesis of chronic ulcer infections.}, } @article {pmid29312246, year = {2017}, author = {Li, Y and Yu, H and Jiang, H and Jiao, Y and Zhang, Y and Shao, J}, title = {Genetic Diversity, Antimicrobial Susceptibility, and Biofilm Formation of Cronobacter spp. Recovered from Spices and Cereals.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2567}, pmid = {29312246}, issn = {1664-302X}, abstract = {Cronobacter species are important food-borne opportunistic pathogens which have been implicated in the cause of necrotizing enterocolitis, sepsis, and meningitis in neonates and infants. However, these bacteria are routinely found in foodstuffs, clinical specimens, and environmental samples. This study investigated the genetic diversity, antimicrobial susceptibility, and biofilm formation of Cronobacter isolates (n = 40) recovered from spices and cereals in China during 2014-2015. Based on the fusA sequencing analysis, we found that the majority (23/40, 57.5%) of Cronobacter isolates in spices and cereals were C. sakazakii, while the remaining strains were C. dublinensis (6/40, 15.0%), C. malonaticus (5/40, 12.5%), C. turicensis (4/40, 10.0%), and C. universalis (2/40, 5.0%). Multilocus sequence typing (MLST) analysis produced 30 sequence types (STs) among the 40 Cronobacter isolates, with 5 STs (ST4, ST13, ST50, ST129, and ST158) related to neonatal meningitis. The pattern of the overall ST distribution was diverse; in particular, it was revealed that ST148 was the predominant ST, presenting 12.5% within the whole population. MLST assigned 12 isolates to 7 different clonal complexes (CCs), 4, 13, 16, 17, 72, 129, and 143, respectively. The results of O-antigen serotyping indicated that C. sakazakii serotype O1 and O2 were the most two prevalent serotypes. The antimicrobial susceptibility testing showed that the 40 Cronobacter isolates were susceptible to most of the antibiotics tested except for ceftriaxone, meropenem, and aztreona. Of the 40 Cronobacter strains tested, 13 (32.5%) were assessed as weak bioflim producers, one (2.5%) was a moderate biofilm producer, one (2.5%) was strong biofilm producer, and the others (62.5%) were non-biofilm producers. MLST and O-antigen serotyping have indicated that Cronobacter strains recovered from spices and cereals were genetically diverse. Isolates of clinical origin, particularly the C. sakazakii ST4 neonatal meningitic pathovar, have been identified from spices and cereals. Moreover, antimicrobial resistance of Cronobacter strains was observed, which may imply a potential public health risk. Therefore, the surveillance of Cronobacter spp. in spices and cereals should be strengthened to improve epidemiological understandings of Cronobacter infections.}, } @article {pmid29312225, year = {2017}, author = {Lopes, W and Vainstein, MH and De Sousa Araujo, GR and Frases, S and Staats, CC and de Almeida, RMC and Schrank, A and Kmetzsch, L and Vainstein, MH}, title = {Geometrical Distribution of Cryptococcus neoformans Mediates Flower-Like Biofilm Development.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2534}, pmid = {29312225}, issn = {1664-302X}, abstract = {Microbial biofilms are highly structured and dynamic communities in which phenotypic diversification allows microorganisms to adapt to different environments under distinct conditions. The environmentally ubiquitous pathogen Cryptococcus neoformans colonizes many niches of the human body and implanted medical devices in the form of biofilms, an important virulence factor. A new approach was used to characterize the underlying geometrical distribution of C. neoformans cells during the adhesion stage of biofilm formation. Geometrical aspects of adhered cells were calculated from the Delaunay triangulation and Voronoi diagram obtained from scanning electron microscopy images (SEM). A correlation between increased biofilm formation and higher ordering of the underlying cell distribution was found. Mature biofilm aggregates were analyzed by applying an adapted protocol developed for ultrastructure visualization of cryptococcal cells by SEM. Flower-like clusters consisting of cells embedded in a dense layer of extracellular matrix were observed as well as distinct levels of spatial organization: adhered cells, clusters of cells and community of clusters. The results add insights into yeast motility during the dispersion stage of biofilm formation. This study highlights the importance of cellular organization for biofilm growth and presents a novel application of the geometrical method of analysis.}, } @article {pmid29311083, year = {2018}, author = {Long, N and Zeng, L and Qiao, S and Li, L and Zhong, G}, title = {Aspergillus fumigatus Afssn3-Afssn8 Pair Reverse Regulates Azole Resistance by Conferring Extracellular Polysaccharide, Sphingolipid Pathway Intermediates, and Efflux Pumps to Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {3}, pages = {}, pmid = {29311083}, issn = {1098-6596}, mesh = {Antifungal Agents/*pharmacology ; Aspergillus fumigatus/*drug effects/*pathogenicity ; Azoles/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Fungal ; Fungal Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Polysaccharides/*metabolism ; Sphingolipids/*metabolism ; }, abstract = {Antifungal treatment is often ineffectual, partly because of biofilm formation. In this study, by using a combined forward and reverse genetic strategy, we identified that nucleus-localized AfSsn3 and its partner AfSsn8, which constitute a Cdk8-cyclin pair, are required for azole resistance in Aspergillus fumigatus Deletion of Afssn3 led to increased absorption and utilization of glucose and amino acids. Interestingly, absorption and utilization of glucose accelerated the extracellular polysaccharide formation, while utilization of the amino acids serine, threonine, and glycine increased sphingolipid pathway intermediate accumulation. In addition, the absence of Afssn3 induced the activity of the efflux pump proteins. These factors indicate the mature biofilm is responsible for the major mechanisms of A. fumigatus resistance to azoles in the ΔAfssn3 mutant. Collectively, the loss of Afssn3 led to two "barrier" layers between the intracellular and extracellular spaces, which consequently decreased drug penetration into the cell.}, } @article {pmid29311080, year = {2018}, author = {Clary, G and Sasindran, SJ and Nesbitt, N and Mason, L and Cole, S and Azad, A and McCoy, K and Schlesinger, LS and Hall-Stoodley, L}, title = {Mycobacterium abscessus Smooth and Rough Morphotypes Form Antimicrobial-Tolerant Biofilm Phenotypes but Are Killed by Acetic Acid.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {3}, pages = {}, pmid = {29311080}, issn = {1098-6596}, support = {P30 CA016058/CA/NCI NIH HHS/United States ; R01 AI059639/AI/NIAID NIH HHS/United States ; }, mesh = {Acetic Acid/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Azithromycin/pharmacology ; Biofilms/*drug effects ; Mycobacterium abscessus/*drug effects ; }, abstract = {Mycobacterium abscessus has emerged as an important pathogen in people with chronic inflammatory lung diseases such as cystic fibrosis, and recent reports suggest that it may be transmissible by fomites. M. abscessus exhibits two major colony morphology variants: a smooth morphotype (Ma[Sm]) and a rough morphotype (Ma[Rg]). Biofilm formation, prolonged intracellular survival, and colony variant diversity can each contribute to the persistence of M. abscessus and other bacterial pathogens in chronic pulmonary diseases. A prevailing paradigm of chronic M. abscessus infection is that Ma[Sm] is a noninvasive, biofilm-forming, persistent phenotype and Ma[Rg] an invasive phenotype that is unable to form biofilms. We show that Ma[Rg] is hyperaggregative and forms biofilm-like aggregates, which, like Ma[Sm] biofilm aggregates, are significantly more tolerant than planktonic variants to acidic pHs, hydrogen peroxide (H2O2), and treatment with amikacin or azithromycin. We further show that both variants are recalcitrant to antibiotic treatment inside human macrophage-like cells and that Ma[Rg] is more refractory than Ma[Sm] to azithromycin. Our results indicate that biofilm-like aggregation and protracted intracellular survival may each contribute to the persistence of this problematic pathogen in the face of antimicrobial agents regardless of morphotype. Biofilms of each M. abscessus variant are rapidly killed, however, by acetic acid, which may help to prevent local fomite transmission.}, } @article {pmid29308789, year = {2018}, author = {Gnanadhas, DP and Elango, M and Janardhanraj, S and Srinandan, CS and Datey, A and Strugnell, RA and Gopalan, J and Chakravortty, D}, title = {Corrigendum: Successful treatment of biofilm infections using shock waves combined with antibiotic therapy.}, journal = {Scientific reports}, volume = {8}, number = {}, pages = {46929}, doi = {10.1038/srep46929}, pmid = {29308789}, issn = {2045-2322}, abstract = {This corrects the article DOI: 10.1038/srep17440.}, } @article {pmid29308194, year = {2017}, author = {Regiel-Futyra, A and Kus-Liśkiewicz, M and Sebastian, V and Irusta, S and Arruebo, M and Kyzioł, A and Stochel, G}, title = {Development of noncytotoxic silver-chitosan nanocomposites for efficient control of biofilm forming microbes.}, journal = {RSC advances}, volume = {7}, number = {83}, pages = {52398-52413}, pmid = {29308194}, issn = {2046-2069}, support = {614715/ERC_/European Research Council/International ; }, abstract = {Severe bacterial and fungal infections have become a major clinical and public health concern. Nowadays, additional efforts are needed to develop effective antimicrobial materials that are not harmful to human cells. This work describes the synthesis and characterization of chitosan-ascorbic acid-silver nanocomposites as films exhibiting high antimicrobial activity and non-cytotoxicity towards human cells. The reductive and stabilizing activity of both the biocompatible polymer chitosan and ascorbic acid were used in the synthesis of silver nanoparticles (AgNPs). Herein, we propose an improved composite synthesis based on medium average molecular weight chitosan with a high deacetylation degree, that together with ascorbic acid gave films with a uniform distribution of small AgNPs (<10 nm) exhibiting high antimicrobial activity against biofilm forming bacterial and fungal strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. At the same time, the resulting solid nanocomposites showed, at the same doses, reduced or totally excluded cytotoxicity on mammalian somatic and tumoral cells. Data obtained in the present study suggest that adequately designed chitosan-silver nanocomposites are powerful and promising materials for reducing pathogenic microorganism-associated infections without harmful effects towards mammalian cells.}, } @article {pmid29307772, year = {2018}, author = {Gao, Y and Mai, B and Wang, A and Li, M and Wang, X and Zhang, K and Liu, Q and Wei, S and Wang, P}, title = {Antimicrobial properties of a new type of photosensitizer derived from phthalocyanine against planktonic and biofilm forms of Staphylococcus aureus.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {316-326}, doi = {10.1016/j.pdpdt.2018.01.003}, pmid = {29307772}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Humans ; Indoles/chemistry/*pharmacology ; Isoindoles ; Photochemotherapy/*methods ; Photosensitizing Agents/chemistry/*pharmacology ; Plankton/*drug effects ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/*drug effects ; }, abstract = {BACKGROUND: Bacterial infection is a common clinical problem. Community-associated Staphylococcus aureus (S. aureus) infections can cause extensive tissue damage and necrosis. Photodynamic antimicrobial chemotherapy (PACT) has recently attracted attention as a feasible bacterial therapy. Octa-cationic zinc phthalocyanines are newly identified photosensitizers derived from phthalocyanines bearing 1, 2-ethanediamine groups and quaternized derivatives with different numbers of positive charges (ZnPc[n+], n = 4 or 8). Here we report the antimicrobial effects of ZnPc[n+]-mediated PACT on planktonic and biofilm cultures of S. aureus.

METHODS: ZnPc[n+] uptake was detected by photometry after alkaline lysis. Dark-toxicity and light-mediated antimicrobial effects of the drug was determined by the plate count method. The production of intracellular reactive oxygen species (ROS) was detected by flow cytometry. SYTO 9 and propidium iodide (PI) were used to detect the bacterial cell membrane permeability. DNA damage after ZnPc[n+]-PACT was analyzed by flow cytometry and PI staining. The destruction of biofilm was evaluated by scanning electron microscope (SEM).

RESULTS: The study of uptake showed that the relative fluorescence intensity of ZnPc[n+] in S. aureus peaked at 15 min. Generation of reactive oxygen species (ROS) by ZnPc[n+] was enhanced in PACT treatment groups. SYTO 9 and PI staining indicated that cell membrane was damaged. Flow cytometry and PI staining revealed DNA damage. Biofilms were damaged in PACT treatment groups.

CONCLUSIONS: Our results suggest that light-activated ZnPc[n+] can efficiently inhibit planktonic and biofilm cultures of S. aureus.}, } @article {pmid29307122, year = {2017}, author = {Stefanetti, V and Bietta, A and Pascucci, L and Marenzoni, ML and Coletti, M and Franciosini, MP and Passamonti, F and Casagrande Proietti, P}, title = {Investigation of the antibiotic resistance and biofilm formation of Staphylococcus pseudintermedius strains isolated from canine pyoderma.}, journal = {Veterinaria italiana}, volume = {53}, number = {4}, pages = {289-296}, doi = {10.12834/VetIt.465.2275.6}, pmid = {29307122}, issn = {1828-1427}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Dog Diseases/*drug therapy/microbiology ; Dogs ; *Drug Resistance, Bacterial ; Pyoderma/drug therapy/microbiology/*veterinary ; Staphylococcus/isolation & purification/*physiology ; }, abstract = {The aim of the present study was to investigate the antibiotic resistance and bio lm formation among a collection of 51 clinical isolates of Staphylococcus pseudintermedius collected from canine pyoderma. All isolates were tested for the susceptibility to a panel of 14 antimicrobial agents by the disk di usion method in Müeller-Hinton agar. Oxacillin resistance was detected by subculture on oxacillin screening agar base. Bio lm formation was investigated by the Microtitre Plate test (MtP) and for some strains by transmission electron microscopy (TEM). Antibiotic resistance pro ling demonstrated that 45/51 S. pseudintermedius isolates had a multi drug resistant (MDR) phenotype, exhibiting simultaneous resistance to at least 3 antibiotics categories; whereas 6 isolates showed a non-MDR phenotype. Thirty strains (59%) were resistant in oxacillin resistant screening agar, the same strains were also positive for mecA by PCR assay. All S. pseudintermedius isolates showed bio lm production by MtP method. Seventeen out of 51 isolates were classi ed as weakly adherent, 26 as moderately adherent, and 8 as strongly adherent. Moreover, no di erence in bio lm formation between meticillin-resistant S. pseudintermedius (MRSP) and meticillin-suscebtible S. pseudintermedius (MSSP) (P value > 0.05) was noted. The antimicrobial resistance mechanisms and bio lm formation could explain the di culty in treating S. pseudintermedius canine infections, chemotherapeutic failure, and consequently persistent infections.}, } @article {pmid29306789, year = {2018}, author = {Huang, C and Liu, WZ and Li, ZL and Zhang, SM and Chen, F and Yu, HR and Shao, SL and Nan, J and Wang, AJ}, title = {High recycling efficiency and elemental sulfur purity achieved in a biofilm formed membrane filtration reactor.}, journal = {Water research}, volume = {130}, number = {}, pages = {1-12}, doi = {10.1016/j.watres.2017.10.043}, pmid = {29306789}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors/microbiology ; *Denitrification ; Nitrates/analysis/chemistry ; Recycling/*methods ; Sulfides/analysis/chemistry ; Sulfur/*analysis/chemistry ; Wastewater/*chemistry ; }, abstract = {Elemental sulfur (S[0]) is always produced during bio-denitrification and desulfurization process, but the S[0] yield and purification quality are too low. Till now, no feasible approach has been carried out to efficiently recover S[0]. In this study, we report the S[0] generation and recovery by a newly designed, compact, biofilm formed membrane filtration reactor (BfMFR), where S[0] was generated within a Thauera sp. strain HDD-formed biofilm on membrane surface, and then timely separated from the biofilm through membrane filtration. The high S[0] generation efficiency (98% in average) was stably maintained under the operation conditions with the influent acetate, nitrate and sulfide concentration of 115, 120 and 100 mg/L, respectively, an initial inoculum volume of approximate 2.4 × 10[8] cells, and a membrane pore size of 0.45 μm. Under this condition, the sulfide loading approached 62.5 kg/m[3]·d, one of the highest compared with the previous reports, demonstrating an efficient sulfide removal and S[0] generation capacity. Particular important, a solid analysis of the effluent revealed that the recovered S[0] was adulterated with barely microorganisms, extracellular polymeric substances (EPSs), or inorganic chemicals, indicating a fairly high S[0] recovery purity. Membrane biofilm analysis revealed that 80.7% of the generated S[0] was accomplished within 45-80 μm of biofilm from the membrane surface and while, the complete membrane fouling due to bacteria and EPSs was generally observed after 14-16 days. The in situ generation and timely separation of S[0] from the bacterial group by BfMFR, effectively avoids the sulfur circulation (S[2-] to S[0], S[0] to SO4[2-], SO4[2-] to HS[-]) and guarantees the high S[0] recovery efficiency and purity, is considered as a feasible approach for S[0] recovery from sulfide- and nitrate-contaminated wastewater.}, } @article {pmid29306701, year = {2018}, author = {Luo, JH and Chen, H and Yuan, Z and Guo, J}, title = {Methane-supported nitrate removal from groundwater in a membrane biofilm reactor.}, journal = {Water research}, volume = {132}, number = {}, pages = {71-78}, doi = {10.1016/j.watres.2017.12.064}, pmid = {29306701}, issn = {1879-2448}, mesh = {Anaerobiosis ; Biofilms ; *Bioreactors/microbiology ; Denitrification ; Groundwater ; Methane/*metabolism ; Methylococcaceae/metabolism ; Nitrates/*metabolism ; Oxidation-Reduction ; Wastewater/microbiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The discovery of denitrifying anaerobic methane oxidation (DAMO) has not only improved our understanding of global methane and nitrogen cycles, but also provided new technology options for removal of nitrate from nitrate-contaminated water. Previous studies have demonstrated DAMO organisms could remove nitrate and nitrite from wastewater under strictly anaerobically conditions. In the study, we investigate the feasibility of nitrate removal from groundwater, which contains dissolved oxygen in addition to nitrate. A membrane biofilm reactor (MBfR), inoculated with DAMO co-culture, was capable of treating synthetic groundwater containing highly contaminated nitrate (50 mg N/L) and oxygen (7-9 mg O2/L), with a maximum volumetric nitrate removal rate of 45 mg N/L-d. Accumulations of acetate and propionate were observed in some transient periods, indicating the possible involvement of acetate and propionate as intermediates in methane oxidation. The 16 S rRNA gene amplicon sequencing revealed that Candidatus Methylomirabilis, a known bacterial DAMO organism able to couple nitrite reduction with anaerobic oxidation of methane (AOM), was the dominant population. No archaeal DAMO organisms that are capable of coupling nitrate to AOM were observed, however, considerable amount of denitrifiers were developed in this system. Based on known metabolisms of these microorganisms and a series of batch studies, it was assumed that methane was oxidized into volatile fatty acids (VFAs) under oxygen-limiting conditions, then the generated VFAs served as carbon sources for these heterotrophic denitrifiers to remove nitrate. This study offers a potential technology for nitrate removal from groundwater by DAMO process in MBfR.}, } @article {pmid29302137, year = {2017}, author = {Ketonis, C and Hickock, NJ and Ilyas, AM}, title = {Rethinking Pyogenic Flexor Tenosynovitis: Biofilm Formation Treated in a Cadaveric Model.}, journal = {Journal of hand and microsurgery}, volume = {9}, number = {3}, pages = {131-138}, pmid = {29302137}, issn = {0974-3227}, abstract = {Introduction Pyogenic flexor tenosynovitis (PFT) of the hand remains a challenging problem that often requires surgical irrigation and parenteral or oral antibiotics. The authors hypothesize that the pathophysiology and microenvironment of PFT can be likened to that of periprosthetic joint infections (PJIs), in which bacteria thrive in a closed synovial space with limited blood supply. As such, they postulate that PFT is also facilitated by bacterial attachment and biofilm formation rendering standard treatments less effective. In this study, they evaluate infected tendons for the presence of biofilm and explore new treatment strategies. Methods Fresh human cadaveric hand tendons were harvested and divided into 0.5-cm segments. Samples were sterilized and inoculated with 1 × 10 [4] CFU/mL green fluorescent Staphylococcus aureus (GFP-SA) for 48 hours at 37°C. After saline washing to remove plank tonic bacteria, samples were treated for 24 hours with (1) saline irrigation, (2) antibiotics (vancomycin), (3) corticosteroids, or (4) antibiotics/corticosteroid combined. Samples were visualized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results Following bacterial challenge, CLSM revealed heterogeneous green fluorescence representing bacterial attachment with dense biofilm formation. SEM at > 3,000X, also demonstrated bacterial colonization in grape-like clusters consisted with a thick matrix characteristic of biofilm. Bacterial load by direct colony counting decreased by 18.5% with saline irrigation alone, 42.6% with steroids, 54.4% with antibiotics, and 77.3% with antibiotics/steroids combined (p < 0.05). Conclusion Staphylococcus aureus readily formed thick biofilm on human cadaveric tendons. The addition of both local antibiotics and corticosteroids resulted in greater decreases in biofilm formation on flexor tendons than the traditional treatment of saline irrigation alone. We suggest rethinking the current treatment of PFT and recommend considering a strategy more analogous to PJI management with the adjunctive use of local antibiotics, corticosteroids, and mechanical agitation.}, } @article {pmid29301295, year = {2018}, author = {Sun, J and Wu, J and An, B and Voogd, NJ and Cheng, W and Lin, W}, title = {Bromopyrrole Alkaloids with the Inhibitory Effects against the Biofilm Formation of Gram Negative Bacteria.}, journal = {Marine drugs}, volume = {16}, number = {1}, pages = {}, pmid = {29301295}, issn = {1660-3397}, mesh = {Alkaloids/chemistry/isolation & purification/*pharmacology ; Animals ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Circular Dichroism ; Escherichia coli/drug effects/physiology ; Gram-Negative Bacteria/drug effects/physiology ; Magnetic Resonance Spectroscopy ; Porifera/*chemistry ; Pyrroles/chemistry/isolation & purification/pharmacology ; Spectrometry, Mass, Electrospray Ionization ; X-Ray Diffraction ; }, abstract = {Anti-biofilm assay guided fractionation of the marine sponge Stylissa massa revealed the butanol soluble fraction that was possessing the inhibitory activity toward the biofilm formation of bacterium E. coli. Chromatographic separation of the bioactive fraction resulted in the isolation of 32 bromopyrrole alkaloids, including six new alkaloids, named stylisines A-F (1-6). The structures of new alkaloids were established by comprehensive analyses of the two-dimensional (2D) NMR (COSY, HMQC, and HMBC) and the high resolution electrospray ionization mass spectroscopy (HRESIMS) data, while the absolute configurations were determined by the X-ray diffraction and the electronic circular dichroism (ECD) data. Bioassay results indicated that phakellin-based alkaloids, including dibromoisophakellin and dibromophakellin, significantly reduced the biofilm formation of the bacterium E. coli. Present work provided a group of new natural scaffolds for the inhibitory effects against the biofilm formation of E. coli.}, } @article {pmid29301116, year = {2018}, author = {Ghaseminezhad, SM and Shojaosadati, SA and Meyer, RL}, title = {Ag/Fe3O4 nanocomposites penetrate and eradicate S. aureus biofilm in an in vitro chronic wound model.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {163}, number = {}, pages = {192-200}, doi = {10.1016/j.colsurfb.2017.12.035}, pmid = {29301116}, issn = {1873-4367}, mesh = {Animals ; Biofilms/*drug effects ; Cell Survival/drug effects ; Chronic Disease ; Ferric Compounds/pharmacology/*therapeutic use ; Humans ; Ions ; Metal Nanoparticles/chemistry/ultrastructure ; *Models, Biological ; Nanocomposites/*chemistry/ultrastructure ; Rats ; Reactive Oxygen Species/metabolism ; Silver/pharmacology/*therapeutic use ; Staphylococcus aureus/drug effects/*physiology ; Starch/chemistry ; Wounds and Injuries/*drug therapy/*microbiology ; }, abstract = {Bacterial biofilms are a common cause of the persistence of chronic wounds, and continue to be an unsolved problem in infection microbiology due to their tolerance to antibiotics. Silver nanoparticles (Ag-NPs) have attracted attention as an alternative to antibiotics for treatment of wound infections, but their use is challenged by limited tissue penetration and high cytotoxicity. The aim of this study was to show that combination of Ag nanoparticles with Fe3O4 to produce Ag/Fe3O4 nanocomposites (NCs) can overcome these problems, as they penetrate and eradicate biofilms when applying a magnetic field. Ag/Fe3O4-NCs were synthesized using starch as a stabilizer and linker between Ag and Fe3O4 NPs, resulting in agglomerations of 20 nm Ag-NPs and 5 nm Fe3O4 NPs. The antibacterial activity was evaluated against an in vitro chronic wound biofilm model, and cytotoxicity was evaluated on human fibroblasts. Increasing the amount of starch during synthesis led to formation of NCs with increased antibacterial activity. In comparison to Ag-NPs, the NCs showed lower Ag[+] release, less ROS production, were less cytotoxic, but nevertheless, their antimicrobial efficacy was higher. Furthermore, their efficiency against biofilm could be enhanced by applying a magnetic field, which ensured penetration of the entire biofilm. In conclusion, Ag/Fe3O4-NCs display important advantages over Ag-NPs as a potential avenue for development of novel therapeutic strategies for treatment of chronic wound infections.}, } @article {pmid29297552, year = {2017}, author = {Huacho, PMM and Nogueira, MNM and Basso, FG and Jafelicci Junior, M and Francisconi, RS and Spolidorio, DMP}, title = {Analyses of Biofilm on Implant Abutment Surfaces Coating with Diamond-Like Carbon and Biocompatibility.}, journal = {Brazilian dental journal}, volume = {28}, number = {3}, pages = {317-323}, doi = {10.1590/0103-6440201601136}, pmid = {29297552}, issn = {1806-4760}, mesh = {Anti-Bacterial Agents ; Bacterial Adhesion ; *Biofilms ; *Carbon ; Cell Line ; *Coated Materials, Biocompatible ; *Dental Abutments ; *Dental Implants ; *Diamond ; Escherichia coli/isolation & purification/physiology ; Humans ; Keratinocytes/cytology ; Polymerase Chain Reaction ; Surface Properties ; }, abstract = {The aim of this study was to evaluate the surface free energy (SFE), wetting and surface properties as well as antimicrobial, adhesion and biocompatibility properties of diamond-like carbon (DLC)-coated surfaces. In addition, the leakage of Escherichia coli through the abutment-dental implant interface was also calculated. SFE was calculated from contact angle values; R a was measured before and after DLC coating. Antimicrobial and adhesion properties against E. coli and cytotoxicity of DLC with human keratinocytes (HaCaT) were evaluated. Further, the ability of DLC-coated surfaces to prevent the migration of E. coli into the external hexagonal implant interface was also evaluated. A sterile technique was used for the semi-quantitative polymerase chain reaction (semi-quantitative PCR). The surfaces showed slight decreases in cell viability (p<0.05), while the SFE, R a, bacterial adhesion, antimicrobial, and bacterial infiltration tests showed no statistically significant differences (p>0.05). It was concluded that DLC was shown to be a biocompatible material with mild cytotoxicity that did not show changes in R a, SFE, bacterial adhesion or antimicrobial properties and did not inhibit the infiltration of E. coli into the abutment-dental implant interface.}, } @article {pmid29295912, year = {2018}, author = {Lee, KJ and Jung, YC and Park, SJ and Lee, KH}, title = {Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by Vibrio Species.}, journal = {mBio}, volume = {9}, number = {1}, pages = {}, pmid = {29295912}, issn = {2150-7511}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Endopeptidase Clp/*metabolism ; Gene Expression Regulation, Bacterial ; Heat-Shock Proteins/*metabolism ; Hot Temperature ; Protease La/*metabolism ; *Quorum Sensing ; Trans-Activators/*metabolism ; Vibrio vulnificus/growth & development/metabolism/*physiology/radiation effects ; }, abstract = {Capsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacterium Vibrio vulnificus CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However, V. vulnificus biofilms formed under heat shock conditions did not exhibit the dispersion stage. Transcripts of the CPS gene cluster were at basal levels in the heat-exposed cell owing to reduced cellular levels of SmcR. At least two proteases induced by heat shock, ClpPA and Lon, were responsible for determining the instability of SmcR. In vitro and in vivo assays demonstrated that SmcR levels were regulated via proteolysis by these proteases, with preferential proteolysis of monomeric SmcR. Thus, CPS production was not induced by QS when bacteria were heat treated. Further studies performed with other Vibrio species demonstrated that high temperature deactivated the QS circuits by increased proteolysis of their QS master regulators, thus resulting in alterations to the QS-regulated phenotypes, including biofilm formation.IMPORTANCE The term "quorum-sensing mechanism" is used to describe diverse bacterial cell density-dependent activities that are achieved by sensing of the signaling molecules and subsequent signal transduction to the master regulators. These well-known bacterial regulatory systems regulate the expression of diverse virulence factors and the construction of biofilms in pathogenic bacteria. There have been numerous studies designed to control bacterial quorum sensing by using small molecules to antagonize the quorum-sensing regulatory components or to interfere with the signaling molecules. In the present study, we showed that the quorum-sensing regulatory circuits of pathogenic Vibrio species were deactivated by heat shock treatment via highly increased proteolysis of the master transcription factors. Our results showed a new mode of quorum deactivation which can be achieved under conditions of high but nonlethal temperature even if the ambient signaling molecules may reach the levels representing high cell density.}, } @article {pmid29295589, year = {2017}, author = {Kang, D and Turner, KE and Kirienko, NV}, title = {PqsA Promotes Pyoverdine Production via Biofilm Formation.}, journal = {Pathogens (Basel, Switzerland)}, volume = {7}, number = {1}, pages = {}, pmid = {29295589}, issn = {2076-0817}, support = {K22 AI110552/AI/NIAID NIH HHS/United States ; }, abstract = {Biofilms create an impermeable barrier against antimicrobial treatment and immune cell access, severely complicating treatment and clearance of nosocomial Pseudomonas aeruginosa infections. We recently reported that biofilm also contributes to pathogen virulence by regulating the production of the siderophore pyoverdine. In this study, we investigated the role of PqsA, a key cell-signaling protein, in this regulatory pathway. We demonstrate that PqsA promotes pyoverdine production in a biofilm-dependent manner. Under nutritionally deficient conditions, where biofilm and pyoverdine are decoupled, PqsA is dispensable for pyoverdine production. Interestingly, although PqsA-dependent pyoverdine production does not rely upon Pseudomonas quinolone signal (PQS) biosynthesis, exogenous PQS can also trigger biofilm-independent production of pyoverdine. Adding PQS rapidly induced planktonic cell aggregation. Moreover, these clumps of cells exhibit strong expression of pyoverdine biosynthetic genes and show substantial production of this siderophore. Finally, we surveyed the relationship between biofilm formation and pyoverdine production in various clinical and environmental isolates of P. aeruginosa to evaluate the clinical significance of targeting biofilm during infections. Our findings implicate PqsA in P. aeruginosa virulence by regulating biofilm formation and pyoverdine production.}, } @article {pmid29294039, year = {2019}, author = {Arce Miranda, JE and Baronetti, JL and Sotomayor, CE and Paraje, MG}, title = {Oxidative and nitrosative stress responses during macrophage-Candida albicans biofilm interaction.}, journal = {Medical mycology}, volume = {57}, number = {1}, pages = {101-113}, doi = {10.1093/mmy/myx143}, pmid = {29294039}, issn = {1460-2709}, mesh = {Animals ; Antifungal Agents/pharmacology ; Antioxidants/metabolism ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/genetics/*physiology ; Drug Resistance, Fungal/genetics ; Host-Pathogen Interactions ; Macrophages/*microbiology/physiology ; Mice ; Models, Biological ; Mutation ; Nitrosative Stress/physiology ; Oxidative Stress/*physiology ; RAW 264.7 Cells ; Reactive Nitrogen Species/metabolism ; Reactive Oxygen Species/metabolism ; }, abstract = {Candida albicans is an important source of device-associated infection because of its capacity for biofilm formation. This yeast has the ability to form biofilms which favors the persistence of the infection. Furthermore, the innate immune response has a critical role in the control of these infections and macrophages (Mø) are vital to this process. An important fungicidal mechanism employed by Mø involves the generation of toxic reactive oxygen species (ROS) and reactive nitrogen intermediates (RNI). The interaction between biofilms and these immune cells, and the contribution of oxidative and nitrosative stress, that is determinant to the course of the infection, remains elusive. The aim of this study was to investigate this interaction. To this purpose, two models of Mø-biofilms contact, early (model 1) and mature (model 2) biofilms, were used; and the production of ROS, RNI and the oxidative stress response (OSR) were evaluated. We found that the presence of Mø decreased the biofilm formation at an early stage and increased the production of ROS and RNI, with activation of ORS (enzymatic and nonenzymatic). On the other hand, the interaction between mature biofilms and Mø resulted in an increasing biofilm formation, with low levels of RNI and ROS production and decrease of OSR. Dynamic interactions between Mø and fungal biofilms were also clearly evident from images obtained by confocal scanning laser microscopy. The prooxidant-antioxidant balance was different depending of C. albicans biofilms stages and likely acts as a signal over their formation in presence of Mø. These results may contribute to a better understanding of the immune-pathogenesis of C. albicans biofilm infections.}, } @article {pmid29293434, year = {2018}, author = {Alonso, B and Cruces, R and Perez, A and Fernandez-Cruz, A and Guembe, M}, title = {Activity of maltodextrin and vancomycin against staphylococcus aureus biofilm.}, journal = {Frontiers in bioscience (Scholar edition)}, volume = {10}, number = {2}, pages = {300-308}, doi = {10.2741/s517}, pmid = {29293434}, issn = {1945-0524}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Drug Therapy, Combination ; Humans ; Polysaccharides/administration & dosage/*pharmacology/therapeutic use ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/physiology ; Vancomycin/administration & dosage/*pharmacology/therapeutic use ; }, abstract = {We aimed to assess the anti-biofilm activity of vancomycin, maltodextrin, and their combination against vancomycin resistant Staphylococcus aureus (VRSA) and vancomycin-susceptible S. aureus (VSSA) strains based on an in vitro static model. Biofilms of 4 VSSA and 2 VRSA strains were grown in a 96-well static model. Vancomycin 2 mM, maltodextrin 10 mM, and both in combination were tested using tetrazolium salt (XTT), resazurin, and cfu/well counts. The efficacy of the antimicrobial solutions was expressed as the percentage reduction in metabolic activity with each method. Overall percentage reduction in the metabolic activity of VSSA was 79.3%, 34%, and 75.7% for vancomycin, maltodextrin, and their combination (p<0.001). Overall percentage reduction in metabolic activity of VRSA was 46.7%, 27.8%, and 34.6% for vancomycin, maltodextrin, and their combination (p>0.05). Maltodextrin did not improve the anti-biofilm efficacy of vancomycin in VSSA or in VRSA biofilms. XTT cannot replace cfu counts as a means of quantifying cell viability. Futures studies are needed to assess the synergistic effects of other non-antimicrobial molecules combined with vancomycin.}, } @article {pmid29293347, year = {2018}, author = {Liu, Y and Balazs, AC}, title = {Modeling Biofilm Formation on Dynamically Reconfigurable Composite Surfaces.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {34}, number = {4}, pages = {1807-1816}, doi = {10.1021/acs.langmuir.7b03765}, pmid = {29293347}, issn = {1520-5827}, mesh = {Adhesiveness ; Adsorption ; *Biofilms ; Biofouling/prevention & control ; Molecular Conformation ; *Molecular Dynamics Simulation ; Polymers/chemistry ; Surface Properties ; }, abstract = {We augment the dissipative particle dynamics (DPD) simulation method to model the salient features of biofilm formation. We simulate a cell as a particle containing hundreds of DPD beads and specify p, the probability of breaking the bond between the particle and surface or between the particles. At the early stages of film growth, we set p = 1, allowing all bonding interactions to be reversible. Once the bound clusters reach a critical size, we investigate scenarios where p = 0, so that incoming species form irreversible bonds, as well as cases where p lies in the range of 0.1-0.5. Using this approach, we examine the nascent biofilm development on a coating composed of a thermoresponsive gel and the embedded rigid posts. We impose a shear flow and characterize the growth rate and the morphology of the clusters on the surface at temperatures above and below Tc, the volume phase transition temperature of a gel that displays lower critical solubility temperature (LCST). At temperatures above Tc, the posts effectively inhibit the development of the nascent biofilm. For temperatures below Tc, the swelling of the gel plays the dominant role and prevents the formation of large clusters of cells. Both these antifouling mechanisms rely on physical phenomena and, hence, are advantageous over chemical methods, which can lead to unwanted, deleterious effects on the environment.}, } @article {pmid29291145, year = {2018}, author = {Swarupa, V and Chaudhury, A and Sarma, PVGK}, title = {Iron enhances the peptidyl deformylase activity and biofilm formation in Staphylococcus aureus.}, journal = {3 Biotech}, volume = {8}, number = {1}, pages = {32}, pmid = {29291145}, issn = {2190-572X}, abstract = {Staphylococcus aureus plays a major role in persistent infections and many of these species form structured biofilms on different surfaces which is accompanied by changes in gene expression profiles. Further, iron supplementation plays a critical role in the regulation of several protein(s)/enzyme function, which all aid in the development of active bacterial biofilms. It is well known that for each protein, deformylation is the most crucial step in biosynthesis and is catalyzed by peptidyl deformylase (PDF). Thus, the aim of the current study is to understand the role of iron in biofilm formation and deformylase activity of PDF. Hence, the PDF gene of S. aureus ATCC12600 was PCR amplified using specific primers and sequenced, followed by cloning and expression in Escherichia coli DH5α. The deformylase activity of the purified recombinant PDF was measured in culture supplemented with/without iron where the purified rPDF showed Km of 1.3 mM and Vmax of 0.035 mM/mg/min, which was close to the native PDF (Km = 1.4 mM, Vmax = 0.030 mM/mg/min). Interestingly, the Km decreased and PDF activity increased when the culture was supplemented with iron, corroborating with qPCR results showing 100- to 150-fold more expression compared to control in S. aureus and its drug-resistant strains. Further biofilm-forming units (BU) showed an incredible increase (0.42 ± 0.005 to 6.3 ± 0.05 BU), i.e., almost 15-fold elevation in anaerobic conditions, indicating the significance of iron in S. aureus biofilms.}, } @article {pmid29290510, year = {2018}, author = {Gholamrezazadeh, M and Shakibaie, MR and Monirzadeh, F and Masoumi, S and Hashemizadeh, Z}, title = {Effect of nano-silver, nano-copper, deconex and benzalkonium chloride on biofilm formation and expression of transcription regulatory quorum sensing gene (rh1R) in drug-resistance Pseudomonas aeruginosa burn isolates.}, journal = {Burns : journal of the International Society for Burn Injuries}, volume = {44}, number = {3}, pages = {700-708}, doi = {10.1016/j.burns.2017.10.021}, pmid = {29290510}, issn = {1879-1409}, mesh = {Anti-Infective Agents/*pharmacology ; Anti-Infective Agents, Local/pharmacology ; Bacterial Proteins/*drug effects/genetics ; Benzalkonium Compounds/*pharmacology ; Biofilms/*drug effects ; Burns/microbiology ; Copper/*pharmacology ; Disinfectants/pharmacology ; Drug Resistance, Bacterial/drug effects/genetics ; Gene Expression/*drug effects ; Humans ; *Metal Nanoparticles ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/*drug effects/genetics ; RNA, Messenger/drug effects/metabolism ; Silver/*pharmacology ; }, abstract = {BACKGROUND: Biofilm forming drug-resistant Pseudomonas aeruginosa are responsible for major death in burn center of different hospitals across the globe.

OBJECTIVE: The aims of this study were to evaluate the effect of nano-silver (Ag), nano-copper (Cu), and two hospital disinfectants (deconex and benzalkonium chloride) on biofilm formation and expression of transcription regulatory quorum sensing gene rh1R in P. aeruginosa burn isolates.

METHODS: 28 multidrug-resistant P. aeruginosa (MDRPA) strains were isolated from patients hospitalized in the burn center of a referral hospital in Kerman, Iran. Sizes and purities of nanoparticles were checked by TEM and X-ray diffraction (XRD) analysis. The Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the nanoparticles (NPs), deconex and benzalkonium chloride were determined by broth microdilution method. Antibiofilm activities of these compounds were measured by microtiter assay. Polymerase chain reaction (PCR) was used for detection of qacEΔ1, cepA, copA and rhlR genes. Quantification of rhlR gene expression in presence and absence of the above compounds was carried out by relative quantitative real-time PCR (qRT-PCR).

RESULTS: Benzalkonium chloride had a potent antimicrobial activity and inhibited growth of all the isolates at MIC 0.06±0.2mg/mL, while nano-Ag was effective at MIC 20±0.2mg/mL. Furthermore, 28.5% of the isolates showed strong, 25% moderate, 14% weak and 32% demonstrated no biofilm activity. Ag NPs exerted highest antibiofilm activity, follow by deconex and benzalkonium chloride. The qacEΔ1 was absent in this study, whereas 17.8% and 60.8% of the isolates were positive for cepA and copA genes. Benzalkonium chloride, Ag NPs and deconex increased the expression of rhlR gene 64, 2 and 7 folds, respectively.

CONCLUSION: Our results suggest that, there is direct relationship between decrease in antibiofilm activity and increase in expression of the rhlR gene in the presence of benzalkonium chloride. Absence of qacEΔ1 gene may be contributed in sensitivity of the isolates to the above agents.}, } @article {pmid29289920, year = {2018}, author = {Xie, GJ and Liu, T and Cai, C and Hu, S and Yuan, Z}, title = {Achieving high-level nitrogen removal in mainstream by coupling anammox with denitrifying anaerobic methane oxidation in a membrane biofilm reactor.}, journal = {Water research}, volume = {131}, number = {}, pages = {196-204}, doi = {10.1016/j.watres.2017.12.037}, pmid = {29289920}, issn = {1879-2448}, mesh = {Ammonium Compounds/metabolism ; Anaerobiosis ; Archaea/genetics/metabolism ; Bacteria/genetics/metabolism ; Biofilms ; *Bioreactors/microbiology ; Denitrification ; In Situ Hybridization, Fluorescence ; Membranes, Artificial ; Methane/*metabolism ; Nitrates/metabolism ; Nitrites/metabolism ; Nitrogen/*metabolism ; Oxidation-Reduction ; RNA, Ribosomal, 16S/genetics ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {To achieve energy neutral wastewater treatment, mainstream anaerobic ammonium oxidation (anammox) has attracted extensive attention in the past decade. However, the relatively high effluent nitrogen concentration (>10 mg N L[-1]) remains a significant barrier hindering its practical implementation. A novel technology integrating the anammox and denitrifying anaerobic methane oxidation (DAMO) reactions in a membrane biofilm reactor (MBfR) was developed in this study to enhance the mainstream anammox process. With the hydraulic retention time (HRT) progressively decreased from 12 to 4 h, the total nitrogen (TN) removal rate increased stepwise from 0.09 to 0.28 kg N m[-3] d[-1], with an effluent TN concentration below 3.0 mg N L[-1] achieved. Mass balance analysis showed that 30-60% of the nitrate produced by the anammox reaction was reduced back to nitrite by DAMO archaea, and the anammox and DAMO bacteria were jointly responsible for nitrite removal with contributions of >90% and <10%, respectively. Additionally, the established MBfR was robust and achieved consistently high effluent quality with >90% TN removal when the influent nitrite to ammonium molar ratio varied in the range of 1.17-1.55. Fluorescence in situ hybridization (FISH) and 16S rRNA gene sequencing indicated that anammox bacteria, DAMO bacteria and DAMO archaea jointly dominated the biofilm, and were likely the key contributors to nitrogen removal. This is the first study that a high nitrogen removal rate (>0.2 kg N m[-3] d[-1]) and satisfactory effluent quality (∼3 mg TN L[-1]) were achieved simultaneously by integrating anammox and DAMO reactions in mainstream wastewater treatment.}, } @article {pmid29288553, year = {2018}, author = {Ausbacher, D and Lorenz, L and Pitts, B and Stewart, PS and Goeres, DM}, title = {Paired methods to measure biofilm killing and removal: a case study with Penicillin G treatment of Staphylococcus aureus biofilm.}, journal = {Letters in applied microbiology}, volume = {66}, number = {3}, pages = {231-237}, doi = {10.1111/lam.12843}, pmid = {29288553}, issn = {1472-765X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Culture Media/pharmacology ; Drug Resistance, Multiple, Bacterial/physiology ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Penicillin G/*pharmacology ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/growth & development ; }, abstract = {UNLABELLED: Biofilms are microbial aggregates that show high tolerance to antibiotic treatments in vitro and in vivo. Killing and removal are both important in biofilm control, therefore methods that measure these two mechanisms were evaluated in a parallel experimental design. Kill was measured using the single tube method (ASTM method E2871) and removal was determined by video microscopy and image analysis using a new treatment flow cell. The advantage of the parallel test design is that both methods used biofilm covered coupons harvested from a CDC biofilm reactor, a well-established and standardized biofilm growth method. The control Staphylococcus aureus biofilms treated with growth medium increased by 0·6 logs during a 3-h contact time. Efficacy testing showed biofilms exposed to 400 μmol l[-1] penicillin G decreased by only 0·3 logs. Interestingly, time-lapse confocal scanning laser microscopy revealed that penicillin G treatment dispersed the biofilm despite being an ineffective killing agent. In addition, no biofilm removal was detected when assays were performed in 96-well plates. These results illustrate that biofilm behaviour and impact of treatments can vary substantially when assayed by different methods. Measuring both killing and removal with well-characterized methods will be crucial for the discovery of new anti-biofilm strategies.

Biofilms are tolerant to antimicrobial treatments and can lead to persistent infections. Finding new anti-biofilm strategies and understanding their mode-of-action is therefore of high importance. Historically, antimicrobial testing has focused on measuring the decrease in viability. While kill data are undeniably important, measuring biofilm disruption provides equally useful information. Starting with biofilm grown in the same reactor, we paired assessment of biofilm removal using a new treatment-flow-cell and real-time microscopy with kill data collected using the single tube method (ASTM E2871). Pairing these two methods revealed efficient biofilm removal properties of Penicillin G which were not detected during efficacy testing.}, } @article {pmid29288453, year = {2018}, author = {Govantes, F}, title = {Serial Dilution-Based Growth Curves and Growth Curve Synchronization for High-Resolution Time Series of Bacterial Biofilm Growth.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1734}, number = {}, pages = {159-169}, doi = {10.1007/978-1-4939-7604-1_13}, pmid = {29288453}, issn = {1940-6029}, mesh = {*Bacterial Physiological Phenomena ; *Biofilms ; *Host-Pathogen Interactions ; Models, Biological ; Plankton/physiology ; Software ; }, abstract = {The ability to form stable surface-attached communities called biofilms is of paramount importance to both beneficial and harmful interactions between microbes and microbial, plant or animal partners. Assessment of biofilm formation ability is often performed by growing the organisms in microtiter plate wells and staining the well-attached material, a method whose use for time-course analysis is limited by its destructive nature. Here we combine a serial dilution-based biofilm growth curve method with online monitoring of planktonic growth and a serially diluted growth curve synchronization algorithm to reconstruct the time-course of planktonic and biofilm growth. As demonstrated here with the rhizosphere bacterium Pseudomonas putida, the method allows accurate determination of the growth rate and doubling time, a robust depiction of the biofilm formation and dispersal dynamics and assessment of the biofilm development defects in mutant strains.}, } @article {pmid29288452, year = {2018}, author = {Amador, CI and Sternberg, C and Jelsbak, L}, title = {Application of RNA-seq and Bioimaging Methods to Study Microbe-Microbe Interactions and Their Effects on Biofilm Formation and Gene Expression.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1734}, number = {}, pages = {131-158}, doi = {10.1007/978-1-4939-7604-1_12}, pmid = {29288452}, issn = {1940-6029}, mesh = {*Biofilms ; Biomarkers ; Flow Cytometry ; *Gene Expression Regulation, Bacterial ; Genetic Engineering ; Genome, Bacterial ; Genomics/methods ; *Microbial Interactions ; *Molecular Imaging ; *Sequence Analysis, RNA/methods ; }, abstract = {Complex interactions between pathogenic bacteria, the microbiota, and the host can modify pathogen physiology and behavior. We describe two different experimental approaches to study microbe-microbe interactions in in vitro systems containing surface-associated microbial populations. One method is the application of RNA sequencing (RNA-seq) to determine the transcriptional changes in pathogenic bacteria in response to microbial interspecies interactions. The other method combines flow cell devices for bacterial cultivation and growth with high-resolution bioimaging to analyze the microscale structural organization of interacting microbial populations within mixed-species biofilms.}, } @article {pmid29288437, year = {2018}, author = {Shreeram, DD and Panmanee, W and McDaniel, CT and Daniel, S and Schaefer, DW and Hassett, DJ}, title = {Effect of impaired twitching motility and biofilm dispersion on performance of Pseudomonas aeruginosa-powered microbial fuel cells.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {45}, number = {2}, pages = {103-109}, pmid = {29288437}, issn = {1476-5535}, support = {1605787//National Science Foundation/ ; }, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Mutation ; Pseudomonas aeruginosa/*genetics ; }, abstract = {Pseudomonas aeruginosa is a metabolically voracious bacterium that is easily manipulated genetically. We have previously shown that the organism is also highly electrogenic in microbial fuel cells (MFCs). Polarization studies were performed in MFCs with wild-type strain PAO1 and three mutant strains (pilT, bdlA and pilT bdlA). The pilT mutant was hyperpiliated, while the bdlA mutant was suppressed in biofilm dispersion chemotaxis. The double pilT bdlA mutant was expected to have properties of both mutations. Polarization data indicate that the pilT mutant showed 5.0- and 3.2-fold increases in peak power compared to the wild type and the pilT bdlA mutant, respectively. The performance of the bdlA mutant was surprisingly the lowest, while the pilT bdlA electrogenic performance fell between the pilT mutant and wild-type bacteria. Measurements of biofilm thickness and bacterial viability showed equal viability among the different strains. The thickness of the bdlA mutant, however, was twice that of wild-type strain PAO1. This observation implicates the presence of dead or dormant bacteria in the bdlA mutant MFCs, which increases biofilm internal resistance as confirmed by electrochemical measurements.}, } @article {pmid29287632, year = {2018}, author = {Treviño-Rangel, RJ and Peña-López, CD and Hernández-Rodríguez, PA and Beltrán-Santiago, D and González, GM}, title = {Association between Candida biofilm-forming bloodstream isolates and the clinical evolution in patients with candidemia: An observational nine-year single center study in Mexico.}, journal = {Revista iberoamericana de micologia}, volume = {35}, number = {1}, pages = {11-16}, doi = {10.1016/j.riam.2017.01.005}, pmid = {29287632}, issn = {2173-9188}, mesh = {Adult ; Biofilms ; Candida/isolation & purification/*physiology ; Candidemia/blood/*microbiology ; Child ; Child, Preschool ; Cross Infection/blood/*microbiology ; Cross-Sectional Studies ; Disease Progression ; Disease Susceptibility ; Female ; Hospitals, University/statistics & numerical data ; Humans ; Infant ; Male ; Mexico ; Middle Aged ; Prognosis ; Retrospective Studies ; Tertiary Care Centers/statistics & numerical data ; }, abstract = {BACKGROUND: Candidemia is one of the most common nosocomial infections globally and it is associated with considerable excess mortality and costs. Abreast, biofilm-forming strains are associated with even higher mortality rates and poor prognosis for the patient.

AIMS: To evaluate a possible association between the biofilm-forming capability of Candida bloodstream isolates and the clinical evolution in patients with candidemia.

METHODS: An observational, retrospective study was conducted at a tertiary care university hospital during 9 years (2006-2015). The biofilm quantitation of the Candida bloodstream isolates was determined by crystal violet staining and XTT reduction assay.

RESULTS: A total of 218 cases of candidemia had been diagnosed and 89 isolates were obtained. The mortality rate was 36% and the main risk factors were antibiotic exposure and the use of catheters. Candida tropicalis (52.8%) was the most frequent species, followed by Candida albicans (30.4%), Candida parapsilosis sensu stricto (10.1%), Candida orthopsilosis (3.4%), Candida krusei (2.2%) and Candida glabrata sensu stricto (1.1%). All the strains were biofilm producers, which is an important contribution to the patient's mortality. C. tropicalis showed the highest production of biomass biofilm, whereas C. glabrata exhibited the highest metabolic activity.

CONCLUSIONS: This study contributes to expand the knowledge about the local epidemiology of candidemia and highlights the impact of Candida biofilm on patient's outcome.}, } @article {pmid29287630, year = {2018}, author = {Montoya, AM and Elizondo-Zertuche, M and Treviño-Rangel, RJ and Becerril-García, M and González, GM}, title = {Biofilm formation and antifungal susceptibility of Trichosporon asahii isolates from Mexican patients.}, journal = {Revista iberoamericana de micologia}, volume = {35}, number = {1}, pages = {22-26}, doi = {10.1016/j.riam.2017.02.008}, pmid = {29287630}, issn = {2173-9188}, mesh = {Adolescent ; Adult ; Aged ; Amphotericin B/pharmacology ; Antifungal Agents/pharmacology ; Biofilms/drug effects ; Child ; Child, Preschool ; Drug Resistance, Fungal ; Female ; Fluconazole/pharmacology ; Humans ; Infant ; Male ; Mexico ; Middle Aged ; Trichosporon/*drug effects/isolation & purification/physiology ; Trichosporonosis/*microbiology ; Young Adult ; }, abstract = {BACKGROUND: Trichosporon asahii is a yeast-like fungus that has recently gained importance as a cause of opportunistic systemic infections. The pathogenicity and virulence factors of T. asahii remain largely unknown. Because of the association between invasive infections and the use of catheters and related devices, the ability of the microorganism to adhere and form biofilms may play an important role in the pathogenicity during a trichosporonosis.

AIMS: The aim of this study is to identify an association between biofilm formation by T. asahii isolates and their genotype and/or clinical source.

METHODS: The biofilm production of 49 T. asahii strains isolated from Mexican patients was measured using the crystal violet stain method, and a comparison made with different adhesion phase incubation times. Antifungal susceptibility testing was performed using a modified CLSI protocol coupled with the quantification of the viable cells with the XTT reduction method.

RESULTS: All the T. asahii isolates assayed were able to produce biofilm in vitro, with an intraspecific variability being observed. Overall, increased biofilm production was found when extending the adhesion phase incubation time from 2 to 4h. No association could be established between the biofilm-producing phenotype and either the genotype or clinical source. Higher antifungal resistance to amphotericin B and fluconazole was linked to increased biofilm production by T. asahii.

CONCLUSIONS: All clinical isolates tested were able to produce biofilm. No association could be established between biofilm formation and genotype or clinical source.}, } @article {pmid29286435, year = {2017}, author = {Gulati, M and Ennis, CL and Rodriguez, DL and Nobile, CJ}, title = {Visualization of Biofilm Formation in Candida albicans Using an Automated Microfluidic Device.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {130}, pages = {}, pmid = {29286435}, issn = {1940-087X}, support = {R21 AI125801/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*physiology ; Humans ; Lab-On-A-Chip Devices/*microbiology ; }, abstract = {Candida albicans is the most common fungal pathogen of humans, causing about 15% of hospital-acquired sepsis cases. A major virulence attribute of C. albicans is its ability to form biofilms, structured communities of cells attached to biotic and abiotic surfaces. C. albicans biofilms can form on host tissues, such as mucosal layers, and on medical devices, such as catheters, pacemakers, dentures, and joint prostheses. Biofilms pose significant clinical challenges because they are highly resistant to physical and chemical perturbations, and can act as reservoirs to seed disseminated infections. Various in vitro assays have been utilized to study C. albicans biofilm formation, such as microtiter plate assays, dry weight measurements, cell viability assays, and confocal scanning laser microscopy. All of these assays are single end-point assays, where biofilm formation is assessed at a specific time point. Here, we describe a protocol to study biofilm formation in real-time using an automated microfluidic device under laminar flow conditions. This method allows for the observation of biofilm formation as the biofilm develops over time, using customizable conditions that mimic those of the host, such as those encountered in vascular catheters. This protocol can be used to assess the biofilm defects of genetic mutants as well as the inhibitory effects of antimicrobial agents on biofilm development in real-time.}, } @article {pmid29286184, year = {2018}, author = {Leonhard, M and Zatorska, B and Tan, Y and Moser, D and Schneider-Stickler, B}, title = {In vitro biofilm growth on modern voice prostheses.}, journal = {Head & neck}, volume = {40}, number = {4}, pages = {763-769}, doi = {10.1002/hed.25053}, pmid = {29286184}, issn = {1097-0347}, mesh = {Biofilms/*growth & development ; Humans ; In Vitro Techniques ; Laryngectomy/methods ; Larynx, Artificial/*microbiology ; *Materials Testing ; Oxides/chemistry ; Polytetrafluoroethylene/chemistry ; Prosthesis Design ; Risk Factors ; Sensitivity and Specificity ; Silver Compounds/chemistry ; }, abstract = {BACKGROUND: Biofilm formation on voice prostheses in laryngectomized patients usually limits the lifetime of the device. The purpose of this study was to compare the biofilm resistance of different valve flaps of modern voice prostheses in an in vitro simulation of an oropharyngeal biofilm.

METHODS: Growth of biofilm deposits on valve flaps (n = 12) removed from Provox 2, Provox Vega, Provox ActiValve, Blom Singer Advantage, and Phonax voice prostheses was evaluated and compared to medical-grade silicone (n = 12) in an in vitro biofilm model (22 days) after incubation with a multispecies bacterial-fungal biofilm composition.

RESULTS: The Provox ActiValve and the Blom Singer Advantage prostheses showed significantly less surface biofilm formation than the other prostheses and then silicone.

CONCLUSION: The use of silver oxide and Teflon as valve flap materials proves to reduce long-term biofilm formation in vitro. The applied model allows rapid screening for novel biofilm-inhibitive materials and durable coatings designated for more biofilm resistant medical devices.}, } @article {pmid29284195, year = {2018}, author = {Florez Salamanca, EJ and Klein, MI}, title = {Extracellular matrix influence in Streptococcus mutans gene expression in a cariogenic biofilm.}, journal = {Molecular oral microbiology}, volume = {33}, number = {2}, pages = {181-193}, doi = {10.1111/omi.12212}, pmid = {29284195}, issn = {2041-1014}, mesh = {Actinomyces/genetics/metabolism ; Adult ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Culture Media ; Dental Caries/microbiology ; Extracellular Matrix/*genetics/*metabolism ; Female ; *Gene Expression Regulation, Bacterial/genetics ; Genes, Bacterial/*genetics ; Humans ; Hydrogen-Ion Concentration ; Lipopolysaccharides/genetics ; Male ; Membrane Proteins/genetics ; Polysaccharides, Bacterial/genetics ; Saliva ; Starch/metabolism ; Streptococcus gordonii/genetics/metabolism ; Streptococcus mutans/*genetics ; Sucrose/metabolism ; Teichoic Acids/genetics ; Young Adult ; }, abstract = {Caries etiology is biofilm-diet-dependent. Biofilms are highly dynamic and structured microbial communities enmeshed in a three-dimensional extracellular matrix. The study evaluated the expression dynamics of Streptococcus mutans genes associated with exopolysaccharides (EPS) (gtfBCD, gbpB, dexA), lipoteichoic acids (LTA) (dltABCD, SMU_775c) and extracellular DNA (eDNA) (lytST, lrgAB, ccpA) during matrix development within a mixed-species biofilm of S. mutans, Actinomyces naeslundii and Streptococcus gordonii. Mixed-species biofilms using S. mutans strains UA159 or ΔgtfB formed on saliva-coated hydroxyapatite discs were submitted to a nutritional challenge (providing an abundance of sucrose and starch). Biofilms were removed at eight developmental stages for gene expression analysis by quantitative polymerase chain reaction. The pH of spent culture media remained acidic throughout the experimental periods, being lower after sucrose and starch exposure. All genes were expressed at all biofilm developmental phases. EPS- and LTA-associated genes had a similar expression profile for both biofilms, presenting lower levels of expression at 67, 91 and 115 hours and a peak of expression at 55 hours, but having distinct expression magnitudes, with lower values for ΔgtfB (eg, fold-difference of ~382 for gtfC and ~16 for dltB at 43 hours). The eDNA-associated genes presented different dynamics of expression between both strains. In UA159 biofilms lrgA and lrgB genes were highly expressed at 29 hours (which were ~13 and ~5.4 times vs ΔgtfB, respectively), whereas in ΔgtfB biofilms an inverse relationship between lytS and lrgA and lrgB expression was detected. Therefore, the deletion of gtfB influences dynamics and magnitude of expression of genes associated with matrix main components.}, } @article {pmid29284102, year = {2018}, author = {Dutra, D and Pereira, G and Kantorski, KZ and Valandro, LF and Zanatta, FB}, title = {Does Finishing and Polishing of Restorative Materials Affect Bacterial Adhesion and Biofilm Formation? A Systematic Review.}, journal = {Operative dentistry}, volume = {43}, number = {1}, pages = {E37-E52}, doi = {10.2341/17-073-L}, pmid = {29284102}, issn = {1559-2863}, mesh = {*Bacterial Adhesion ; *Biofilms ; *Dental Materials/adverse effects ; *Dental Polishing/methods ; Dental Restoration, Permanent/adverse effects/*methods ; Humans ; }, abstract = {Biofilm (bacterial plaque) accumulation on the surface of restorative materials favors the occurrence of secondary caries and periodontal inflammation. Surface characteristics of restorations can be modified by finishing and/or polishing procedures and may affect bacterial adhesion. The aim of this systematic review was to characterize how finishing and polishing methods affect the surface properties of different restorative materials with regard to bacterial adhesion and biofilm formation. Searches were carried out in MEDLINE-PubMed, EMBASE, Cochrane-CENTRAL, and LILACS databases. From 2882 potential articles found in the initial searches, only 18 met the eligible criteria and were included in this review (12 with in vitro design, four with in situ design, and two clinical trials). However, they presented high heterogeneity regarding materials considered and methodology for evaluating the desired outcome. Risk bias analysis showed that only two studies presented low risk (whereas 11 showed high and five showed medium risk). Thus, only descriptive analyses considering study design, materials, intervention (finishing/polishing), surface characteristics (roughness and surface free energy), and protocol for biofilm formation (bacterial adhesion) could be performed. Some conclusions could be drawn: the impact of roughness on bacterial adhesion seems to be related not to a roughness threshold (as previously believed) but rather to a range, the range of surface roughness among different polishing methods is wide and material dependent, finishing invariably creates a rougher surface and should always be followed by a polishing method, each dental material requires its own treatment modality to obtain and maintain as smooth a surface as possible, and in vitro designs do not seem to be powerful tools to draw relevant conclusions, so in vivo and in situ designs become strongly recommended.}, } @article {pmid29282421, year = {2017}, author = {Asayesh, F and Zarabadi, MP and Greener, J}, title = {A new look at bubbles during biofilm inoculation reveals pronounced effects on growth and patterning.}, journal = {Biomicrofluidics}, volume = {11}, number = {6}, pages = {064109}, pmid = {29282421}, issn = {1932-1058}, abstract = {Specially designed microfluidic bioflow cells were used to temporarily trap microbubbles during different inoculation stages of Pseudomonas sp. biofilms. Despite being eliminated many hours before biofilm appearance, templated growth could occur at former bubble positions. Bubble-templated growth was either continuous or in ring patterns, depending on the stage of inoculation when the bubbles were introduced. Templated biofilms were strongly enhanced in terms of their growth kinetics and structural homogeneity. High resolution confocal imaging showed two separate bubble-induced bacterial trapping modes, which were responsible for the altered biofilm development. It is concluded that static bubbles can be exploited for fundamental improvements to bioreactor performance, as well as open new avenues to study isolated bacteria and small colonies.}, } @article {pmid29282165, year = {2017}, author = {Vinson, LA and Goodlett, AK and Huang, R and Eckert, GJ and Gregory, RL}, title = {In Vitro Effects of Sports and Energy Drinks on Streptococcus mutans Biofilm Formation and Metabolic Activity.}, journal = {Journal of dentistry for children (Chicago, Ill.)}, volume = {84}, number = {3}, pages = {108-114}, pmid = {29282165}, issn = {1935-5068}, mesh = {Bacteriological Techniques ; Biofilms/*drug effects/growth & development ; Dental Plaque/microbiology ; Dietary Sugars/analysis ; *Energy Drinks/analysis ; Humans ; Hydrogen-Ion Concentration ; *Sports ; Streptococcus mutans/drug effects/metabolism/*physiology ; }, abstract = {PURPOSE: Sports and energy drinks are being increasingly consumed and contain large amounts of sugars, which are known to increase Streptococcus mutans biofilm formation and metabolic activity. The purpose of this in vitro study was to investigate the effects of sports and energy drinks on S. mutans biofilm formation and metabolic activity.

METHODS: S. mutans UA159 was cultured with and without a dilution (1:3 ratio) of a variety of sports and energy drinks in bacterial media for 24 hours. The biofilm was washed, fixed, and stained. Biofilm growth was evaluated by reading absorbance of the crystal violet. Biofilm metabolic activity was measured by the biofilm-reducing XTT to a water-soluble orange compound.

RESULTS: Gatorade Protein Recovery Shake and Starbucks Doubleshot Espresso Energy were found to significantly increase biofilm (30-fold and 22-fold, respectively) and metabolic activity (2-fold and 3-fold, respectively). However, most of the remaining drinks significantly inhibited biofilm growth and metabolic activity.

CONCLUSIONS: Several sports and energy drinks, with sugars or sugar substitutes as their main ingredients inhibited S. mutans biofilm formation. Among the drinks evaluated, Gatorade Protein Recovery Chocolate Shake and Starbucks Doubleshot Energy appear to have cariogenic potential since they increased the biofilm formation and metabolic activity of S. mutans.}, } @article {pmid29282118, year = {2017}, author = {Kaczorek, E and Małaczewska, J and Wójcik, R and Siwicki, AK}, title = {Biofilm production and other virulence factors in Streptococcus spp. isolated from clinical cases of bovine mastitis in Poland.}, journal = {BMC veterinary research}, volume = {13}, number = {1}, pages = {398}, pmid = {29282118}, issn = {1746-6148}, mesh = {Animals ; *Biofilms ; Cattle ; DNA, Bacterial/genetics ; Female ; Mastitis, Bovine/epidemiology/*microbiology ; Milk/microbiology ; Poland/epidemiology ; Polymerase Chain Reaction/veterinary ; Streptococcal Infections/epidemiology/microbiology/*veterinary ; *Streptococcus/genetics ; Streptococcus agalactiae/genetics ; Virulence Factors/*genetics ; }, abstract = {BACKGROUND: Mastitis is a common disease in dairy cattle throughout the world and causes considerable economic losses each year. An important aetiological agent of this disease is bacteria of the genus Streptococcus; hence, exploring the mechanisms of virulence in these bacteria is an extremely important step for the development of effective prevention programmes. The purpose of our study was to determine the ability to produce biofilm and the occurrence of selected invasiveness factors among bacteria of the genus Streptococcus isolated from cattle with the clinical form of mastitis in northeastern Poland.

RESULTS: Most of the isolates analysed demonstrated an ability to produce biofilm (over 70%). Virulence genes were searched for in the three most common streptococci in our experiment: S. agalactiae, S. uberis and S. dysgalactiae. For S. agalactiae, only four genes were confirmed: rib (33%), cylE (78%), bca (37%), and cfb (100%). The genes pavA, scpB, bac and lmb were not present in any of the tested strains. The dominant serotypes of the species were Ia (n = 8) and II (n = 8), in addition to some strains that were not classified in any of the groups (n = 6). Out of the eight selected genes for S. uberis (sua, pauA/skc, gapC, cfu, lbp, hasA, hasB, hasC), only one was not found (lbp). Finally, two genes were chosen for S. dysgalactiae (eno and napr), and their presence was confirmed in 76% and 86% of the strains, respectively.

CONCLUSIONS: The experiment showed that strains of Streptococcus spp. isolated from dairy cattle with clinical cases of mastitis in the northeastern part of Poland possess several invasiveness factors that can substantially affect the course of the disease, and this should be considered when developing targeted prevention programmes.}, } @article {pmid29280609, year = {2018}, author = {Wolfmeier, H and Pletzer, D and Mansour, SC and Hancock, REW}, title = {New Perspectives in Biofilm Eradication.}, journal = {ACS infectious diseases}, volume = {4}, number = {2}, pages = {93-106}, doi = {10.1021/acsinfecdis.7b00170}, pmid = {29280609}, issn = {2373-8227}, support = {MOP-74493//CIHR/Canada ; }, mesh = {Anti-Infective Agents/*pharmacology ; Bacterial Infections/drug therapy/microbiology ; Biofilms/*drug effects ; Drug Delivery Systems ; Drug Resistance, Bacterial ; Electrochemical Techniques ; Humans ; }, abstract = {Microbial biofilms, which are elaborate and highly resistant microbial aggregates formed on surfaces or medical devices, cause two-thirds of infections and constitute a serious threat to public health. Immunocompromised patients, individuals who require implanted devices, artificial limbs, organ transplants, or external life support and those with major injuries or burns, are particularly prone to become infected. Antibiotics, the mainstay treatments of bacterial infections, have often proven ineffective in the fight against microbes when growing as biofilms, and to date, no antibiotic has been developed for use against biofilm infections. Antibiotic resistance is rising, but biofilm-mediated multidrug resistance transcends this in being adaptive and broad spectrum and dependent on the biofilm growth state of organisms. Therefore, the treatment of biofilms requires drug developers to start thinking outside the constricted "antibiotics" box and to find alternative ways to target biofilm infections. Here, we highlight recent approaches for combating biofilms focusing on the eradication of preformed biofilms, including electrochemical methods, promising antibiofilm compounds and the recent progress in drug delivery strategies to enhance the bioavailability and potency of antibiofilm agents.}, } @article {pmid29280044, year = {2018}, author = {Anjum, A and Sim, CH and Ng, SF}, title = {Hydrogels Containing Antibiofilm and Antimicrobial Agents Beneficial for Biofilm-Associated Wound Infection: Formulation Characterizations and In vitro Study.}, journal = {AAPS PharmSciTech}, volume = {19}, number = {3}, pages = {1219-1230}, doi = {10.1208/s12249-017-0937-4}, pmid = {29280044}, issn = {1530-9932}, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry/therapeutic use ; Bacterial Infections/drug therapy ; Biofilms/*drug effects ; Carboxymethylcellulose Sodium/chemistry ; Drug Carriers/*chemistry ; Drug Liberation ; Edetic Acid/administration & dosage ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Humans ; Hydrogels/*chemistry ; Wound Healing/drug effects ; Wound Infection/drug therapy ; Xylitol/administration & dosage ; }, abstract = {Bacterial biofilm which adheres onto wound surface is shown to be impervious to antibiotics and this in turn delays wound healing. Previous studies showed that antibiofilm agents such as xylitol and ethylenediaminetetraacetic acid (EDTA) prevent bacterial adherence onto surfaces. Formulation of a wound dressing containing antibiofilm agents may be a plausible strategy in breaking the biofilm on wound surfaces and at the same time increase the efficacy of the antibiotic. The purpose of this study was to develop hydrogel formulations containing antibiofilm agents along with antibiotic (gentamicin) for bacterial biofilm-associated wound infection. Sodium carboxymethyl cellulose (NaCMC) hydrogels loaded with antibiofilm agents and antibiotic were prepared. The hydrogels were characterized for their physical properties, rheology, Fourier transform infrared spectroscopy (FTIR), drug content uniformity, differential scanning calorimetry (DSC) and in vitro drug release study. The antibiofilm (Crystal Violet staining and XTT assay) and antibacterial performances of the hydrogels against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli were assessed in vitro. The formulated hydrogels showed adequate release of both antibiofilm agents (xylitol and EDTA). Both antimicrobial and antibiofilm tests showed promising results and demonstrated that the combination of xylitol, EDTA, and gentamicin had an additive effect against both Gram-positive and Gram-negative bacteria. In summary, NaCMC (sodium carboxymethyl cellulose) hydrogels containing the combination of antimicrobial and antibiofilm agents were successfully developed and this can be a new strategy in combating biofilm in wound infection which in turn accelerate wound healing.}, } @article {pmid29279769, year = {2017}, author = {Anwander, M and Rosentritt, M and Schneider-Feyrer, S and Hahnel, S}, title = {Biofilm formation on denture base resin including ZnO, CaO, and TiO2 nanoparticles.}, journal = {The journal of advanced prosthodontics}, volume = {9}, number = {6}, pages = {482-485}, pmid = {29279769}, issn = {2005-7806}, abstract = {PURPOSE: This laboratory study aimed to investigate the effect of doping an acrylic denture base resin material with nanoparticles of ZnO, CaO, and TiO2 on biofilm formation.

MATERIALS AND METHODS: Standardized specimens of a commercially available cold-curing acrylic denture base resin material were doped with 0.1, 0.2, 0.4, or 0.8 wt% commercially available ZnO, CaO, and TiO2 nanopowder. Energy dispersive X-ray spectroscopy (EDX) was used to identify the availability of the nanoparticles on the surface of the modified specimens. Surface roughness was determined by employing a profilometric approach; biofilm formation was simulated using a monospecies Candida albicans biofilm model and a multispecies biofilm model including C. albicans, Actinomyces naeslundii, and Streptococcus gordonii. Relative viable biomass was determined after 20 hours and 44 hours using a MTT-based approach.

RESULTS: No statistically significant disparities were identified among the various materials regarding surface roughness and relative viable biomass.

CONCLUSION: The results indicate that doping denture base resin materials with commercially available ZnO, CaO, or TiO2 nanopowders do not inhibit biofilm formation on their surface. Further studies might address the impact of varying particle sizes as well as increasing the fraction of nanoparticles mixed into the acrylic resin matrix.}, } @article {pmid29279615, year = {2017}, author = {Ghivari, SB and Bhattacharya, H and Bhat, KG and Pujar, MA}, title = {Antimicrobial activity of root canal irrigants against biofilm forming pathogens- An in vitro study.}, journal = {Journal of conservative dentistry : JCD}, volume = {20}, number = {3}, pages = {147-151}, pmid = {29279615}, issn = {0972-0707}, abstract = {AIMS: The aim of the study was to check the antimicrobial activity of the 5% Sodium hypochlorite, 2% Chlorhexidine, 0.10% Octenidine (OCT), and 2% Silver Zeolite (SZ) at different time intervals against a single species biofilm of Enterococcus faecalis, Staphylococcus aureus, and Candida albicans model prepared on a nitrocellulose membrane.

SETTINGS AND DESIGN: In vitro nitrocellulose biofilm model was used to check antibacterial efficacy of root canal irrigants.

MATERIALS AND METHODS: The in vitro nitrocellulose biofilm model was used to check the antibacterial activity of root canal irrigants. Single species biofilms were suspended into 96-well microtiter plate and treated with root canal irrigants for 1, 5, 10, 15, 30, and 60 s, respectively. The remaining microbial load in the form of colony-forming unit/ml after antimicrobial treatment was tabulated and data were statistically analyzed.

STATISTICAL ANALYSIS: SPSS version 17, Kruskal-Wallis ANOVA, Mann-Whitney U-test, and Wilcoxon matched pair test (P < 0.05) were used.

RESULTS: All tested microorganisms were eliminated within 30 s by all the antimicrobial substances tested except normal saline. 2% chlorhexidine and 0.10% OCT were equally effective against C. albicans at 30 s.

CONCLUSION: The newly tested irrigants have shown considerable antibacterial activity against selected single species biofilm. OCT (0.10%) can be used as an alternative endodontic irrigant.}, } @article {pmid29276509, year = {2017}, author = {Aleksic, I and Petkovic, M and Jovanovic, M and Milivojevic, D and Vasiljevic, B and Nikodinovic-Runic, J and Senerovic, L}, title = {Anti-biofilm Properties of Bacterial Di-Rhamnolipids and Their Semi-Synthetic Amide Derivatives.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2454}, pmid = {29276509}, issn = {1664-302X}, abstract = {A new strain, namely Lysinibacillus sp. BV152.1 was isolated from the rhizosphere of ground ivy (Glechoma hederacea L.) producing metabolites with potent ability to inhibit biofilm formation of an important human pathogens Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and Serratia marcescens. Structural characterization revealed di-rhamnolipids mixture containing rhamnose (Rha)-Rha-C10-C10, Rha-Rha-C8-C10, and Rha-Rha-C10-C12 in the ratio 7:2:1 as the active principle. Purified di-rhamnolipids, as well as commercially available di-rhamnolipids (Rha-Rha-C10-C10, 93%) were used as the substrate for the chemical derivatization for the first time, yielding three semi-synthetic amide derivatives, benzyl-, piperidine-, and morpholine. A comparative study of the anti-biofilm, antibacterial and cytotoxic properties revealed that di-Rha from Lysinibacillus sp. BV152.1 were more potent in biofilm inhibition, both cell adhesion and biofilm maturation, than commercial di-rhamnolipids inhibiting 50% of P. aeruginosa PAO1 biofilm formation at 50 μg mL[-1] and 75 μg mL[-1], respectively. None of the di-rhamnolipids exhibited antimicrobial properties at concentrations of up to 500 μg mL[-1]. Amide derivatization improved inhibition of biofilm formation and dispersion activities of di-rhamnolipids from both sources, with morpholine derivative being the most active causing more than 80% biofilm inhibition at concentrations 100 μg mL[-1]. Semi-synthetic amide derivatives showed increased antibacterial activity against S. aureus, and also showed higher cytotoxicity. Therefore, described di-rhamnolipids are potent anti-biofilm agents and the described approach can be seen as viable approach in reaching new rhamnolipid based derivatives with tailored biological properties.}, } @article {pmid29276508, year = {2017}, author = {Bas, S and Kramer, M and Stopar, D}, title = {Biofilm Surface Density Determines Biocide Effectiveness.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2443}, pmid = {29276508}, issn = {1664-302X}, abstract = {High resistance of biofilms for chemical challenges is a serious industrial and medical problem. In this work a gradient of surface covered with biofilm has been produced and correlated to the effectiveness of different commercially available oxidative biocides. The results for thin Escherichia coli biofilms grown in rich media supplemented with glucose or lactose on glass or poly methyl methacrylate surfaces indicate that the effectiveness of hydrogen peroxide or chlorine dioxide and quaternary ammonium compounds is inversely proportional to the fraction of the surface covered with the biofilm. In areas where biofilm covered more than 90% of the available surface the biocide treatment was inefficient after 60 min of incubation. The combined effect of oxidant and surfactant increased the effectiveness of the biocide. On the other hand, the increased biofilm viscoelasticity reduced biocide effectiveness. The results emphasize differential biocide effectiveness depending on the fraction of the attached bacterial cells. The results suggest that biofilm biocide resistance is an acquired property that increases with biofilm maturation. The more dense sessile structures present lower log reductions compared to less dense ones.}, } @article {pmid29275280, year = {2018}, author = {Papaioannou, E and Giaouris, ED and Berillis, P and Boziaris, IS}, title = {Dynamics of biofilm formation by Listeria monocytogenes on stainless steel under mono-species and mixed-culture simulated fish processing conditions and chemical disinfection challenges.}, journal = {International journal of food microbiology}, volume = {267}, number = {}, pages = {9-19}, doi = {10.1016/j.ijfoodmicro.2017.12.020}, pmid = {29275280}, issn = {1879-3460}, mesh = {Animals ; Biofilms/*growth & development ; Colony Count, Microbial ; Disinfectants/*pharmacology ; Disinfection/*standards ; Fishes/microbiology ; *Food-Processing Industry ; Listeria monocytogenes/*drug effects/*physiology ; *Stainless Steel ; }, abstract = {The progressive ability of a six-strains L. monocytogenes cocktail to form biofilm on stainless steel (SS), under fish-processing simulated conditions, was investigated, together with the biocide tolerance of the developed sessile communities. To do this, the pathogenic bacteria were left to form biofilms on SS coupons incubated at 15°C, for up to 240h, in periodically renewable model fish juice substrate, prepared by aquatic extraction of sea bream flesh, under both mono-species and mixed-culture conditions. In the latter case, L. monocytogenes cells were left to produce biofilms together with either a five-strains cocktail of four Pseudomonas species (fragi, savastanoi, putida and fluorescens), or whole fish indigenous microflora. The biofilm populations of L. monocytogenes, Pseudomonas spp., Enterobacteriaceae, H2S producing and aerobic plate count (APC) bacteria, both before and after disinfection, were enumerated by selective agar plating, following their removal from surfaces through bead vortexing. Scanning electron microscopy was also applied to monitor biofilm formation dynamics and anti-biofilm biocidal actions. Results revealed the clear dominance of Pseudomonas spp. bacteria in all the mixed-culture sessile communities throughout the whole incubation period, with the in parallel sole presence of L. monocytogenes cells to further increase (ca. 10-fold) their sessile growth. With respect to L. monocytogenes and under mono-species conditions, its maximum biofilm population (ca. 6logCFU/cm[2]) was reached at 192h of incubation, whereas when solely Pseudomonas spp. cells were also present, its biofilm formation was either slightly hindered or favored, depending on the incubation day. However, when all the fish indigenous microflora was present, biofilm formation by the pathogen was greatly hampered and never exceeded 3logCFU/cm[2], while under the same conditions, APC biofilm counts had already surpassed 7logCFU/cm[2] by the end of the first 96h of incubation. All here tested disinfection treatments, composed of two common food industry biocides gradually applied for 15 to 30min, were insufficient against L. monocytogenes mono-species biofilm communities, with the resistance of the latter to significantly increase from the 3rd to 7th day of incubation. However, all these treatments resulted in no detectable L. monocytogenes cells upon their application against the mixed-culture sessile communities also containing the fish indigenous microflora, something probably associated with the low attached population level of these pathogenic cells before disinfection (<10[2]CFU/cm[2]) under such mixed-culture conditions. Taken together, all these results expand our knowledge on both the population dynamics and resistance of L. monocytogenes biofilm cells under conditions resembling those encountered within the seafood industry and should be considered upon designing and applying effective anti-biofilm strategies.}, } @article {pmid29274394, year = {2018}, author = {Araújo, TSD and Rodrigues, PLF and Santos, MS and de Oliveira, JM and Rosa, LP and Bagnato, VS and Blanco, KC and da Silva, FC}, title = {Reduced methicillin-resistant Staphylococcus aureus biofilm formation in bone cavities by photodynamic therapy.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {219-223}, doi = {10.1016/j.pdpdt.2017.12.011}, pmid = {29274394}, issn = {1873-1597}, mesh = {Animals ; Bacteriological Techniques ; Biofilms/*drug effects ; Cattle ; Curcumin/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Spectrometry, Fluorescence ; }, abstract = {UNLABELLED: Photodynamic Therapy (PDT) is a promising alternative for the treatment of infectious bone lesions in the oral cavity. The objective of this study was to evaluate the antimicrobial effectiveness of PDT using blue LED associated with curcumin in methicillin-resistant Staphylococcus aureus biofilms (MRSA) in bovine bone cavities by fluorescence spectroscopy. Standardized suspensions of MRSA culture were inoculated into bone lesions to form biofilm. Forty bone species were distributed in three distinct groups: L-C- (control); L + C- (LED for 5 min); L-C+ (curcumin incubation for 5 min) and L + C+ (PDT). Aliquots of 100 μL were collected from the bone cavities after the treatments and were cultived in BHI for 24 h at 36 °C ± 1 and bacterial colonies counting were performed. Statistical analysis were performed using the paired t-test and analysis of variance (ANOVA) for the variables studied.

RESULTS: The control and PDT groups presented statistically significant differences (p < 0.001). It was possible to reduce 3.666 log10 CFU/mL of MRSA and a reduction in the fluorescence emitted after the treatments was observed. The MRSA reduction in biofilms by PDT was the most efficient treatmnent. There was a significant reduction of biofilms in the L + C- and non-PDT groups by fluorescence spectroscopy images.}, } @article {pmid29273811, year = {2017}, author = {Díaz-Salazar, C and Calero, P and Espinosa-Portero, R and Jiménez-Fernández, A and Wirebrand, L and Velasco-Domínguez, MG and López-Sánchez, A and Shingler, V and Govantes, F}, title = {The stringent response promotes biofilm dispersal in Pseudomonas putida.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {18055}, pmid = {29273811}, issn = {2045-2322}, mesh = {Adhesins, Bacterial/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Promoter Regions, Genetic ; Pseudomonas putida/*metabolism ; Stress, Physiological/*physiology ; }, abstract = {Biofilm dispersal is a genetically programmed response enabling bacterial cells to exit the biofilm in response to particular physiological or environmental conditions. In Pseudomonas putida biofilms, nutrient starvation triggers c-di-GMP hydrolysis by phosphodiesterase BifA, releasing inhibition of protease LapG by the c-di-GMP effector protein LapD, and resulting in proteolysis of the adhesin LapA and the subsequent release of biofilm cells. Here we demonstrate that the stringent response, a ubiquitous bacterial stress response, is accountable for relaying the nutrient stress signal to the biofilm dispersal machinery. Mutants lacking elements of the stringent response - (p)ppGpp sythetases [RelA and SpoT] and/or DksA - were defective in biofilm dispersal. Ectopic (p)ppGpp synthesis restored biofilm dispersal in a ∆relA ∆spoT mutant. In vivo gene expression analysis showed that (p)ppGpp positively regulates transcription of bifA, and negatively regulates transcription of lapA and the lapBC, and lapE operons, encoding a LapA-specific secretion system. Further in vivo and in vitro characterization revealed that the PbifA promoter is dependent on the flagellar σ factor FliA, and positively regulated by ppGpp and DksA. Our results indicate that the stringent response stimulates biofilm dispersal under nutrient limitation by coordinately promoting LapA proteolysis and preventing de novo LapA synthesis and secretion.}, } @article {pmid29273511, year = {2018}, author = {Singh, A and Gupta, R and Tandon, S and Prateeksha, and Pandey, R}, title = {Anti-biofilm and anti-virulence potential of 3,7-dimethyloct-6-enal derived from Citrus hystrix against bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae.}, journal = {Microbial pathogenesis}, volume = {115}, number = {}, pages = {264-271}, doi = {10.1016/j.micpath.2017.12.051}, pmid = {29273511}, issn = {1096-1208}, mesh = {Acyclic Monoterpenes ; Aldehydes/*pharmacology ; Biofilms/*growth & development ; Citrus/*chemistry ; Gene Expression Regulation, Bacterial/drug effects ; Monoterpenes/*pharmacology ; Movement/drug effects ; Oils, Volatile/*pharmacology ; Oryza/*microbiology ; Plant Diseases/microbiology ; Plant Leaves/microbiology ; Plant Oils/*pharmacology ; Virulence Factors/genetics ; Xanthomonas/*drug effects/genetics/pathogenicity ; }, abstract = {The present investigation for the first time explains the anti biofilm and anti virulence potential of Kaffir lime oil (KLO) and its major constituent, Citronellal (3,7-dimethyloct-6-enal) against Xanthomonas oryzae pv. oryzae, causal organism of bacterial blight disease of rice. KLO at 500 ppm showed potential activity against X. oryzae pv. oryzae. Among the major components identified, citronellal (CIT) at 75 μM concentration was found to significantly inhibit biofilm along with the swimming and swarming potential of X. oryzae pv. oryzae. In contrary, CIT did not affect the metabolic status and growth kinetics of the bacterial cells. Gene expression analysis showed down regulation in motA, cheD, cheY, flgF, gumC, xylanase, endogluconase, cellulose, cellobiosidase, virulence and rpfF transcript levels by citronellal treatment. However, an insignificant effect of 75 μM CIT treatment was observed on motB, flgE, pilA, estY, pglA, protease and lytic genes expression. Finally, the observations recorded were in confirmity with the virulence leaf clip test as lesion length was significantly decreased (39%) in CIT treatment as compared to the control leaves inoculated with only X. oryzae pv. oryzae. Overall, the findings obtained advocate the use of CIT for promising anti biofilm and anti virulence activity which in turn can be used for managing the blight disease in rice.}, } @article {pmid29272975, year = {2019}, author = {Kavitha, S and HariKrishnan, A and Jeevaratnam, K}, title = {Purification and identification of 4-allylbenzene-1,2-diol: an antilisterial and biofilm preventing compound from the leaves of Piper betle L. var Pachaikodi.}, journal = {Natural product research}, volume = {33}, number = {10}, pages = {1514-1517}, doi = {10.1080/14786419.2017.1419239}, pmid = {29272975}, issn = {1478-6427}, mesh = {Allyl Compounds/chemistry/*pharmacology ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Benzene Derivatives/chemistry/*pharmacology ; Biofilms/drug effects ; Chromatography, High Pressure Liquid ; Drug Evaluation, Preclinical/methods ; Listeria monocytogenes/*drug effects ; Piper betle/*chemistry ; Plant Extracts/chemistry/pharmacology ; Plant Leaves/chemistry ; }, abstract = {Antibiotic-resistant food-borne Listeriosis has been rising with up to 30% mortality threat in humans since several decades. Hence, discovering antilisterial from the extracts of ethnomedicinal plants may be of value as a novel antidote. In our preceding study, we reported that ethanolic extract of Piper betle L. var Pachaikodi leaves exhibited antibacterial activity towards Listeria monocytogenes MTCC 657. Consequently in the present study, the bioactive molecule responsible for anti-Listeria activity was purified and identified as 4-allylbenzene-1,2-diol. This identified bioactive compound may have significance while used as antimicrobials and/or food additives in food processing sector as evidenced by dual action: biofilm inhibition and pore formation on cell membrane.}, } @article {pmid29272578, year = {2018}, author = {Sommer, R and Wagner, S and Rox, K and Varrot, A and Hauck, D and Wamhoff, EC and Schreiber, J and Ryckmans, T and Brunner, T and Rademacher, C and Hartmann, RW and Brönstrup, M and Imberty, A and Titz, A}, title = {Glycomimetic, Orally Bioavailable LecB Inhibitors Block Biofilm Formation of Pseudomonas aeruginosa.}, journal = {Journal of the American Chemical Society}, volume = {140}, number = {7}, pages = {2537-2545}, doi = {10.1021/jacs.7b11133}, pmid = {29272578}, issn = {1520-5126}, mesh = {Administration, Oral ; Biofilms/*drug effects ; Biological Availability ; Cinnamates/administration & dosage/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Kinetics ; Lectins/*antagonists & inhibitors/metabolism ; Molecular Conformation ; Pseudomonas aeruginosa/*drug effects/metabolism ; Structure-Activity Relationship ; Sulfonamides/administration & dosage/chemistry/*pharmacology ; Thermodynamics ; }, abstract = {The opportunistic Gram-negative bacterium Pseudomonas aeruginosa is a leading pathogen for infections of immuno-compromised patients and those suffering from cystic fibrosis. Its ability to switch from planktonic life to aggregates, forming the so-called biofilms, is a front-line mechanism of antimicrobial resistance. The bacterial carbohydrate-binding protein LecB is an integral component and necessary for biofilm formation. Here, we report a new class of drug-like low molecular weight inhibitors of the lectin LecB with nanomolar affinities and excellent receptor binding kinetics and thermodynamics. This class of glycomimetic inhibitors efficiently blocked biofilm formation of P. aeruginosa in vitro while the natural monovalent carbohydrate ligands failed. Furthermore, excellent selectivity and pharmacokinetic properties were achieved. Notably, two compounds showed good oral bioavailability, and high compound concentrations in plasma and urine were achieved in vivo.}, } @article {pmid29272217, year = {2019}, author = {Manu, DS and Thalla, AK}, title = {Influence of various operating conditions on wastewater treatment in an AS-biofilm reactor and post-treatment using TiO2-based solar/UV photocatalysis.}, journal = {Environmental technology}, volume = {40}, number = {10}, pages = {1271-1288}, doi = {10.1080/09593330.2017.1420697}, pmid = {29272217}, issn = {1479-487X}, mesh = {Biofilms ; Bioreactors ; Nitrogen ; *Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {In the present study, the effect of carbon to nitrogen (C/N) ratio, suspended biomass concentration (X), hydraulic retention time (HRT) and dissolved oxygen (DO) on chemical oxygen demand (COD) and nutrient removal from wastewater was investigated in a lab-scale activated sludge (AS)-biofilm reactor. Furthermore, in order to improve the quality of the treated wastewater, photocatalysis by TiO2 was investigated as a post-treatment technology, using solar and UV irradiations. The AS-biofilm reactor provided a substantial removal efficiency in terms of COD, ammonia nitrogen (NH4+-N) , total nitrogen (TN) and total phosphorous when the system was maintained at C/N ratio 6.66, X in the range 2-2.5 g/L, HRT 10 h, DO in the range of 3.5-4.5 mg/L and organic loading rate (OLR) of 0.96 kg COD/m[3 ]d during Run 1. Similarly, when the reactor was maintained at C/N ratio 10, X in the range of 3-3.5 g/L, HRT 8 h, DO in the range of 3.5-4.5 mg/L and OLR of 1.8 kg COD/m[3 ]d during Run 2. The microstructure of suspended and attached biomass comprised a dense bacterial structure of cocci and bacillus microorganisms. The UV photocatalysis was found to be better than solar photocatalysis during the comparative analysis. The maximum removal efficiencies of COD, most probable number and phosphorous at optimum conditions in the case of UV and solar irradiations were 72%, 95%, 52% and 71%, 99%, 50%, respectively.}, } @article {pmid29269493, year = {2018}, author = {Feng, J and Ma, L and Nie, J and Konkel, ME and Lu, X}, title = {Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {5}, pages = {}, pmid = {29269493}, issn = {1098-5336}, mesh = {Bacterial Adhesion/*physiology ; *Biofilms ; Campylobacter jejuni/genetics/*physiology ; DNA, Bacterial/genetics/*metabolism ; Stress, Physiological ; }, abstract = {Campylobacter jejuni is a microaerophilic bacterium and is believed to persist in a biofilm to antagonize environmental stress. This study investigated the influence of environmental conditions on the formation of C. jejuni biofilm. We report an extracellular DNA (eDNA)-mediated mechanism of biofilm formation in response to aerobic and starvation stress. The eDNA was determined to represent a major form of constitutional material of C. jejuni biofilms and to be closely associated with bacterial lysis. Deletion mutation of the stress response genes spoT and recA enhanced the aerobic influence by stimulating lysis and increasing eDNA release. Flagella were also involved in biofilm formation but mainly contributed to attachment rather than induction of lysis. The addition of genomic DNA from either Campylobacter or Salmonella resulted in a concentration-dependent stimulation effect on biofilm formation, but the effect was not due to forming a precoating DNA layer. Enzymatic degradation of DNA by DNase I disrupted C. jejuni biofilm. In a dual-species biofilm, eDNA allocated Campylobacter and Salmonella at distinct spatial locations that protect Campylobacter from oxygen stress. Our findings demonstrated an essential role and multiple functions of eDNA in biofilm formation of C. jejuni, including facilitating initial attachment, establishing and maintaining biofilm, and allocating bacterial cells.IMPORTANCECampylobacter jejuni is a major cause of foodborne illness worldwide. In the natural environment, the growth of C. jejuni is greatly inhibited by various forms of environmental stress, such as aerobic stress and starvation stress. Biofilm formation can facilitate the distribution of C. jejuni by enabling the survival of this fragile microorganism under unfavorable conditions. However, the mechanism of C. jejuni biofilm formation in response to environmental stress has been investigated only partially. The significance of our research is in identifying extracellular DNA released by bacterial lysis as a major form of constitution material that mediates the formation of C. jejuni biofilm in response to environmental stress, which enhances our understanding of the formation mechanism of C. jejuni biofilm. This knowledge can aid the development of intervention strategies to limit the distribution of C. jejuni.}, } @article {pmid29269492, year = {2018}, author = {Laganenka, L and Sourjik, V}, title = {Autoinducer 2-Dependent Escherichia coli Biofilm Formation Is Enhanced in a Dual-Species Coculture.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {5}, pages = {}, pmid = {29269492}, issn = {1098-5336}, mesh = {Biofilms/*growth & development ; Carrier Proteins/*metabolism ; Coculture Techniques ; Enterococcus faecalis/growth & development/*physiology ; Escherichia coli/growth & development/*physiology ; Escherichia coli Proteins/*metabolism ; }, abstract = {Biofilms in nature typically consist of multiple species, and microbial interactions are likely to have crucial effects on biofilm development, structure, and functions. The best-understood form of communication within bacterial communities involves the production, release, and detection of signal molecules (autoinducers), known as quorum sensing. Although autoinducers mainly promote intraspecies communication, autoinducer 2 (AI-2) is produced and detected by a variety of bacteria, thus principally allowing interspecies communication. Here we show the importance of AI-2-mediated signaling in the formation of mixed biofilms by Enterococcus faecalis and Escherichia coli Our results demonstrate that AI-2 produced by E. faecalis promotes collective behaviors of E. coli at lower cell densities, enhancing autoaggregation of E. coli but also leading to chemotaxis-dependent coaggregation between the two species. Finally, we show that formation of such mixed dual-species biofilms increases the stress resistance of both E. coli and E. faecalisIMPORTANCE The role of interspecies communication in the development of mixed microbial communities is becoming increasingly apparent, but specific examples of such communication remain limited. The universal signal molecule AI-2 is well known to regulate cell-density-dependent phenotypes of many bacterial species but, despite its potential for interspecies communication, the role of AI-2 in the establishment of multispecies communities is not well understood. In this study, we explore AI-2 signaling in a dual-species community containing two bacterial species that naturally cooccur in their mammalian hosts, i.e., Escherichia coli and Enterococcus faecalis We show that active production of AI-2 by E. faecalis allows E. coli to perform collective behaviors at low cell densities. Additionally, AI-2- and chemotaxis-dependent coaggregation with E. faecalis creates nucleation zones for rapid growth of E. coli microcolonies in mixed biofilms and enhances the stress resistance of both species.}, } @article {pmid29269246, year = {2018}, author = {Muslim, SN and Mohammed Ali, AN and Al-Kadmy, IMS and Khazaal, SS and Ibrahim, SA and Al-Saryi, NA and Al-Saadi, LG and Muslim, SN and Salman, BK and Aziz, SN}, title = {Screening, nutritional optimization and purification for phytase produced by Enterobacter aerogenes and its role in enhancement of hydrocarbons degradation and biofilm inhibition.}, journal = {Microbial pathogenesis}, volume = {115}, number = {}, pages = {159-167}, doi = {10.1016/j.micpath.2017.12.047}, pmid = {29269246}, issn = {1096-1208}, mesh = {6-Phytase/*metabolism ; *Biodegradation, Environmental ; Biofilms/growth & development ; Enterobacter aerogenes/*enzymology/genetics/isolation & purification/*metabolism ; Environmental Pollution/analysis ; Fuel Oils/*microbiology ; Hydrocarbons/*metabolism ; Hydrophobic and Hydrophilic Interactions ; Phytic Acid/*metabolism ; RNA, Ribosomal, 16S/genetics ; Soil/chemistry ; Soil Microbiology ; Soil Pollutants/*metabolism ; }, abstract = {In this study, a novel isolate of Enterobacter aerogenes isolated from contaminated soils with hydrocarbons had extracellular phytate-degrading activity. Enterobacter aerogenes isolates were identified by biochemical tests and confirmed by16S rRNA gene products (amplified size 211bp) for genotypic detection. The phytase activity was reached to maximum activity when this isolate was cultivated under the optimal conditions which consisted of using minimal salt medium containing 1%(w/v) rice bran as a sole source for carbon and 2% (w/v) yeast extract at pH 5.5 and temperature of 50°C for 48 h. The phytase had purified to homogeneity by 50% ammonium sulphate precipitation, ion exchange and gel filtration chromatography with 75.7 fold of purification and a yield of 30.35%. The purified phytase is a single peptide with approximate molecular mass of 42 kDa as assessed by SDS-PAGE. The highest degradative ability by Enterobacter aerogenes of black oil, white oil and used engine oil had observed after 72 h of incubation. Rapid degradation of black oil and used engine oil had also observed while slow degradation of white oilat all time of incubation. The purified phytase inhibited biofilm formation ability in a dose-dependent manner for all Gram-negative and Gram-positive biofilm-forming bacteria and a significant difference in cell surface hydrophobicity was observed after exposure of planktonic cells to phytase for hour. The hydrolyzing effect of phytase released by Enterobacter aerogenes for complex salts of phosphorus that are insoluble in the soil led to increase of phosphorus concentrations and enhanced the ability of Enterobacter aerogenes to degrade a specific hydrocarbon in contaminated soil so that the phytase has a promising application in bioremediation of contaminated soils with hydrocarbons.}, } @article {pmid29268634, year = {2018}, author = {Suwarno, SR and Huang, W and Chew, YMJ and Tan, SHH and Trisno, AE and Zhou, Y}, title = {On-line biofilm strength detection in cross-flow membrane filtration systems.}, journal = {Biofouling}, volume = {34}, number = {2}, pages = {123-131}, doi = {10.1080/08927014.2017.1409892}, pmid = {29268634}, issn = {1029-2454}, mesh = {*Biofilms ; Biofouling/*prevention & control ; Filtration/*methods ; *Membranes, Artificial ; Pseudomonas aeruginosa/*growth & development ; Water Purification/*methods ; }, abstract = {A fluid dynamic gauging (FDG) technique was used for on-line and in situ measurements of Pseudomonas aeruginosa PAO1 biofilm thickness and strength on flat sheet polyethersulphone membranes. The measurements are the first to be successfully conducted in a membrane cross-flow filtration system under constant permeation. In addition, FDG was used to demonstrate the removal behaviour of biofilms through local biofilm strength and removal energy estimation, which other conventional measurements such as flux and TMP cannot provide. The findings suggest that FDG can provide valuable additional information related to biofilm properties that have not been measured by other monitoring methods.}, } @article {pmid29263111, year = {2018}, author = {Ota, C and Morisaki, H and Nakata, M and Arimoto, T and Fukamachi, H and Kataoka, H and Masuda, Y and Suzuki, N and Miyazaki, T and Okahashi, N and Kuwata, H}, title = {Streptococcus sanguinis Noncoding cia-Dependent Small RNAs Negatively Regulate Expression of Type IV Pilus Retraction ATPase PilT and Biofilm Formation.}, journal = {Infection and immunity}, volume = {86}, number = {3}, pages = {}, pmid = {29263111}, issn = {1098-5522}, mesh = {Adenosine Triphosphatases/genetics/*metabolism ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Down-Regulation ; Fimbriae, Bacterial/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; RNA, Bacterial/*genetics/metabolism ; RNA, Small Untranslated/genetics/*metabolism ; Streptococcal Infections/*microbiology ; Streptococcus sanguis/*genetics/physiology ; }, abstract = {Small noncoding RNAs (sRNAs) have been identified as important regulators of gene expression in various cellular processes. cia-dependent small RNAs (csRNAs), a group of sRNAs that are controlled by the two-component regulatory system CiaRH, are widely conserved in streptococci, but their targets have been identified only in Streptococcus pneumoniaeStreptococcus sanguinis, a pioneer colonizer of teeth and one of the most predominant bacteria in the early oral biofilm, has been shown to have six csRNAs. Using computational target prediction and the luciferase reporter assay, we identified pilT, a constituent of the type IV pilus operon, as a negative regulatory target for one of the csRNAs, namely, csRNA1-1, in S. sanguinis RNA-RNA electrophoretic mobility shift assay using a nucleotide exchange mutant of csRNA1-1 revealed that csRNA1-1 binds directly to pilT mRNA. In addition, csRNA1-1 and csRNA1-2, a putative gene duplication product of csRNA1-1 that is tandemly located in the S. sanguinis genome, negatively regulated S. sanguinis biofilm formation. These results suggest the involvement of csRNAs in the colonization step of S. sanguinis.}, } @article {pmid29259083, year = {2017}, author = {Das, J and Mokrzan, E and Lakhani, V and Rosas, L and Jurcisek, JA and Ray, WC and Bakaletz, LO}, title = {Extracellular DNA and Type IV Pilus Expression Regulate the Structure and Kinetics of Biofilm Formation by Nontypeable Haemophilus influenzae.}, journal = {mBio}, volume = {8}, number = {6}, pages = {}, pmid = {29259083}, issn = {2150-7511}, support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 GM103612/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Computer Simulation ; DNA, Bacterial/*metabolism ; Fimbriae, Bacterial/*metabolism ; Haemophilus influenzae/*physiology ; Image Processing, Computer-Assisted ; Microscopy, Confocal ; }, abstract = {Biofilms formed in the middle ear by nontypeable Haemophilus influenzae (NTHI) are central to the chronicity, recurrence, and refractive nature of otitis media (OM). However, mechanisms that underlie the emergence of specific NTHI biofilm structures are unclear. We combined computational analysis tools and in silico modeling rooted in statistical physics with confocal imaging of NTHI biofilms formed in vitro during static culture in order to identify mechanisms that give rise to distinguishing morphological features. Our analysis of confocal images of biofilms formed by NTHI strain 86-028NP using pair correlations of local bacterial densities within sequential planes parallel to the substrate showed the presence of fractal structures of short length scales (≤10 μm). The in silico modeling revealed that extracellular DNA (eDNA) and type IV pilus (Tfp) expression played important roles in giving rise to the fractal structures and allowed us to predict a substantial reduction of these structures for an isogenic mutant (ΔcomE) that was significantly compromised in its ability to release eDNA into the biofilm matrix and had impaired Tfp function. This prediction was confirmed by analysis of confocal images of in vitro ΔcomE strain biofilms. The fractal structures potentially generate niches for NTHI survival in the hostile middle ear microenvironment by dramatically increasing the contact area of the biofilm with the surrounding environment, facilitating nutrient exchange, and by generating spatial positive feedback to quorum signaling.IMPORTANCE NTHI is a major bacterial pathogen for OM, which is a common ear infection in children worldwide. Chronic OM is associated with bacterial biofilm formation in the middle ear; therefore, knowledge of the mechanisms that underlie NTHI biofilm formation is important for the development of therapeutic strategies for NTHI-associated OM. Our combined approach using confocal imaging of NTHI biofilms formed in vitro and mathematical tools for analysis of pairwise density correlations and agent-based modeling revealed that eDNA and Tfp expression were important factors in the development of fractal structures in NTHI biofilms. These structures may help NTHI survive in hostile environments, such as the middle ear. Our in silico model can be used in combination with laboratory or animal modeling studies to further define the mechanisms that underlie NTHI biofilm development during OM and thereby guide the rational design of, and optimize time and cost for, benchwork and preclinical studies.}, } @article {pmid29258219, year = {2017}, author = {Petrachi, T and Resca, E and Piccinno, MS and Biagi, F and Strusi, V and Dominici, M and Veronesi, E}, title = {An Alternative Approach to Investigate Biofilm in Medical Devices: A Feasibility Study.}, journal = {International journal of environmental research and public health}, volume = {14}, number = {12}, pages = {}, pmid = {29258219}, issn = {1660-4601}, mesh = {Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Equipment and Supplies/*microbiology ; Feasibility Studies ; Gentian Violet/chemistry ; Microscopy/*methods ; }, abstract = {Biofilms are assemblages of bacterial cells irreversibly associated with a surface where moisture is present. In particular, they retain a relevant impact on public health since through biofilms bacteria are able to survive and populate biomedical devices causing severe nosocomial infections that are generally resistant to antimicrobial agents. Therefore, controlling biofilm formation is a mandatory feature during medical device manufacturing and during their use. In this study, combining a crystal violet staining together with advanced stereomicroscopy, we report an alternative rapid protocol for both qualitative and semi-quantitative biofilm determination having high specificity, high repeatability, and low variability. The suggested approach represents a reliable and versatile method to detect, monitor, and measure biofilm colonization by an easy, more affordable, and reproducible method.}, } @article {pmid29257728, year = {2018}, author = {Dhowlaghar, N and Abeysundara, PA and Nannapaneni, R and Schilling, MW and Chang, S and Cheng, WH and Sharma, CS}, title = {Growth and Biofilm Formation by Listeria monocytogenes in Catfish Mucus Extract on Four Food Contact Surfaces at 22 and 10°C and Their Reduction by Commercial Disinfectants.}, journal = {Journal of food protection}, volume = {81}, number = {1}, pages = {59-67}, doi = {10.4315/0362-028X.JFP-17-103}, pmid = {29257728}, issn = {1944-9097}, mesh = {Animals ; Biofilms/*growth & development ; Catfishes ; Chlorine/pharmacology ; Disinfectants/*pharmacology ; Food Contamination/analysis ; Food Microbiology ; Listeria monocytogenes/*growth & development ; Mucus ; Peracetic Acid/pharmacology ; Stainless Steel/*analysis ; Temperature ; }, abstract = {The objective of this study was to determine the effect of strain and temperature on growth and biofilm formation by Listeria monocytogenes in high and low concentrations of catfish mucus extract on various food contact surfaces at 10 and 22°C. The second objective of this study was to evaluate the efficacy of disinfectants at recommended concentrations and contact times for removing L. monocytogenes biofilm cells from a stainless steel surface covered with catfish mucus extract. Growth and biofilm formation of all L. monocytogenes strains increased with higher concentrations of catfish mucus extract at both 10 and 22°C. When 15 μg/mL catfish mucus extract was added to 3 log CFU/mL L. monocytogenes, the biofilm levels of L. monocytogenes on stainless steel reached 4 to 5 log CFU per coupon at 10°C and 5 to 6 log CFU per coupon at 22°C in 7 days. With 375 μg/mL catfish mucus extract, the biofilm levels of L. monocytogenes on stainless steel reached 5 to 6 log CFU per coupon at 10°C and 6 to 7.5 log CFU per coupon at 22°C in 7 days. No differences (P > 0.05) were observed between L. monocytogenes strains tested for biofilm formation in catfish mucus extract on the stainless steel surface. The biofilm formation by L. monocytogenes catfish isolate HCC23 was lower on Buna-N rubber than on stainless steel, polyethylene, and polyurethane surfaces in the presence of catfish mucus extract (P < 0.05). Contact angle analysis and atomic force microscopy confirmed that Buna-N rubber was highly hydrophobic, with lower surface energy and less roughness than the other three surfaces. The complete reduction of L. monocytogenes biofilm cells was achieved on the stainless steel coupons with a mixture of disinfectants, such as quaternary ammonium compounds with hydrogen peroxide or peracetic acid with hydrogen peroxide and octanoic acid at 25 or 50% of the recommended concentration, in 1 or 3 min compared with use of the quaternary ammonium compounds, chlorine, or acid disinfectants alone, which were ineffective for removing all the L. monocytogenes biofilm cells.}, } @article {pmid29257002, year = {2018}, author = {Danino, MA and Efanov, JI and Dimitropoulos, G and Moreau, M and Maalouf, C and Nelea, M and Izadpanah, A and Giot, JP}, title = {Capsular Biofilm Formation at the Interface of Textured Expanders and Human Acellular Dermal Matrix: A Comparative Scanning Electron Microscopy Study.}, journal = {Plastic and reconstructive surgery}, volume = {141}, number = {4}, pages = {919-928}, doi = {10.1097/PRS.0000000000004216}, pmid = {29257002}, issn = {1529-4242}, mesh = {Acellular Dermis/*microbiology ; Adult ; Aged ; *Biofilms ; Breast Implantation/*instrumentation/methods ; Breast Implants ; Female ; Humans ; *Microscopy, Electron, Scanning ; Middle Aged ; Pilot Projects ; Prospective Studies ; Tissue Expansion/*instrumentation/methods ; Tissue Expansion Devices/*microbiology ; }, abstract = {BACKGROUND: Despite benefits in reducing capsular contractures, textured implants have been associated with significant pitfalls, such a propensity for biofilm formation. Few studies have investigated whether the use of acellular dermal matrix on textured implants produces similar findings. This study aims to characterize biofilm formation at the capsular-acellular dermal matrix interface with scanning electron microscopy.

METHODS: The authors performed a prospective observational pilot study in patients undergoing two-stage expander-to-permanent implant exchange. Patients were inflated with Biocell or Siltex expanders, and specimens from the capsular-pectoralis interface and capsular-acellular dermal matrix interface were obtained and examined under scanning electron microscopy for capsular ingrowth and biofilm formation using the Van Herdeen Biofilm Grading System and the Biofilm Thickness Grading Scale.

RESULTS: Nine patients including 14 breasts (28 capsular samples in total) were examined. Thick biofilm formation was observed in all specimens from the capsular-acellular dermal matrix interface with Biocell and 25 percent of capsule-pectoralis interface, whereas no biofilm formation was found in Siltex implants. For Biocell implants, a significant difference in biofilm coverage between the upper and lower poles was observed using the Van Herdeen Biofilm Grading System (p = 0.0028) and the Biofilm Thickness Grading Scale (p = 0.0161).

CONCLUSIONS: Biocell implants produce a significant rate of biofilm formation over acellular dermal matrix-covered capsules, which is not present in the muscular region or in Siltex implants. Further randomized controlled trials will further elucidate the clinical impact of using acellular dermal matrices with macrotextured implants.

Therapeutic, IV.}, } @article {pmid29255281, year = {2018}, author = {Price, JE and Chapman, MR}, title = {Phaged and confused by biofilm matrix.}, journal = {Nature microbiology}, volume = {3}, number = {1}, pages = {2-3}, doi = {10.1038/s41564-017-0078-2}, pmid = {29255281}, issn = {2058-5276}, support = {R01 GM118651/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins ; *Biofilms ; *Extracellular Polymeric Substance Matrix ; }, } @article {pmid29254815, year = {2018}, author = {Kishen, A and Shrestha, A and Del Carpio-Perochena, A}, title = {Validation of Biofilm Assays to Assess Antibiofilm Efficacy in Instrumented Root Canals after Syringe Irrigation and Sonic Agitation.}, journal = {Journal of endodontics}, volume = {44}, number = {2}, pages = {292-298}, doi = {10.1016/j.joen.2017.10.005}, pmid = {29254815}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms/drug effects/growth & development ; Dental Pulp Cavity/microbiology ; Humans ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Reproducibility of Results ; Root Canal Irrigants/*pharmacology ; Root Canal Preparation/instrumentation/*methods ; Ultrasonic Therapy ; }, abstract = {INTRODUCTION: Different methods to characterize bacterial biofilms have been established, each presenting with distinct advantages and shortcomings. The aim of this study was to validate the ability of microbiological culture, the adenosine-5'-triphosphate (luminescence) assay, molecular, and microscopic methods to assess antibiofilm efficacy.

METHODS: Thirty-nine extracted single-rooted teeth were selected. Enterococcus faecalis biofilms were grown for 21 days and randomly distributed into 3 groups. All canals were instrumented (F3 ProTaper Universal; Dentsply Sirona, Johnson City, TN) and irrigated (ProRinse needles, Dentsply Sirona) as follows: group 1, sodium hypochlorite and EDTA irrigation; group 2, supplemented with sonic agitation of NaOCl, and group 3, sterile distilled water irrigation. Bacteriologic samples were collected before (S1) and after canal preparation (S2) and subjected to quantification by culture methods, quantitative reverse transcriptase real-time PCR (qRT-PCR), and luminescence assay. The biofilm structure and bacterial cell viability were evaluated under scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Data were subjected to statistical analysis to determine the statistical significance (P < .05).

RESULTS: S1 samples showed approximately 8-log colony-forming-units of bacteria using both culture and qRT-PCR. The reduction in bacterial population and relative luminescence was highly significant in the S2 samples from groups 1 and 2 (P < .001). SEM and CLSM showed well-matured root canal biofilms in the pretreatment samples that were reduced after treatment. Irrigation with NaOCl combined with sonic agitation significantly decreased the percentage of live cells (P < .05) but was not able to eliminate the biofilm structure.

CONCLUSIONS: This study highlighted the maximum reduction of microbes after instrumentation-syringe irrigation. Although supplementary sonic agitation reduced the root canal biofilm further, it did not completely eliminate the biofilm from a single root canal model. The merits of combining microbiological and molecular quantification methods with CLSM for the comprehensive assessment of antibiofilm efficacy in root canals were emphasized.}, } @article {pmid29253782, year = {2018}, author = {Zhu, Y and Tu, X and Chai, XS and Wei, Q and Guo, L}, title = {Biological activities and nitrogen and phosphorus removal during the anabaena flos-aquae biofilm growth using different nutrient form.}, journal = {Bioresource technology}, volume = {251}, number = {}, pages = {7-12}, doi = {10.1016/j.biortech.2017.12.003}, pmid = {29253782}, issn = {1873-2976}, mesh = {Anabaena ; Biofilms ; *Dolichospermum flos-aquae ; Microalgae ; *Nitrogen ; *Phosphorus ; }, abstract = {This work investigated the biological activities and nitrogen and phosphorus removal during the anabaena flos-aquae biofilm growth on the polyvinyl chloride (PVC) carriers, in different nutrient form mediums. The study showed that the production of dehydrogenase activity (DHA) and extracellular polymeric substances (EPS) can reach 40.4 g/(h·m[2]) and 115 × 10[-2] g/m[2] in an 11-day period, respectively, indicating that the anabaena flos-aquae biofilm had high biological activities. The results showed that the nitrogen and phosphorus removal reached 94.9 and 96.8%, respectively, in the ammonium form nitrogen group; while 97.7% of phosphorus were removed in the orthophosphate form phosphorous group. A comparison study was conducted and results showed that the present anabaena flos-aquae based biofilm provided a better removal of nitrogen and phosphorus than the other microalgae biofilms.}, } @article {pmid29251486, year = {2018}, author = {Mauro, N and Schillaci, D and Varvarà, P and Cusimano, MG and Geraci, DM and Giuffrè, M and Cavallaro, G and Maida, CM and Giammona, G}, title = {Branched High Molecular Weight Glycopolypeptide With Broad-Spectrum Antimicrobial Activity for the Treatment of Biofilm Related Infections.}, journal = {ACS applied materials & interfaces}, volume = {10}, number = {1}, pages = {318-331}, doi = {10.1021/acsami.7b16573}, pmid = {29251486}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Microbial Sensitivity Tests ; Molecular Weight ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Vancomycin ; }, abstract = {There are few therapeutic options to simultaneously tackle Staphylococcus aureus and Pseudomonas aeruginosa, two of the most relevant nosocomial and antibiotic-resistant pathogens responsible for implant, catheters and wound severe infections. The design and synthesis of polymers with inherent antimicrobial activity have gained increasing attention as a safe strategy to treat multi-drug-resistant microbes. Here, we tested the activity of a new polymeric derivative with glycopolypeptide architecture (PAA-VC) bearing l-arginine, vancomycin, and colistin as side chains acting against multiple targets, which give rise to a broad spectrum antimicrobial activity favorably combining specific and nonspecific perturbation of the bacterial membrane. PAA-VC has been tested against planktonic and established biofilms of reference strains S. aureus ATCC 25923 and P. aeruginosa ATCC 15442 and susceptible or antibiotic resistant clinical isolates of the above-mentioned microorganisms. MIC values observed for the conjugate (48-190 and 95-190 nM for P. aeruginosa and S. aureus strains, respectively) showed higher efficacy if compared with the free vancomycin (MICs within 1.07-4.28 μM) and colistin (MICs within 0.63-1.33 μM). Additionally, being highly biocompatible (IC50 > 1000, 430, and 250 μg mL[-1] for PAA-VC, vancomycin and colistin respectively) high-dosage can be adopted for the eradication of infections in patients. This positively influences the anti-biofilm activity of the conjugate leading to a quasi-total eradication of established clinically relevant biofilms (inhibition >90% at 500 μg mL[-1]). We believe that the in vitro presented data, especially the activity against established biofilms of two relevant pathogens, the high biocompatibility and the good mucoadhesion properties, would allow the use of PAA-VC as promising candidate to successfully address emerging infections.}, } @article {pmid29248513, year = {2018}, author = {Khodadadian, R and Rahdar, HA and Javadi, A and Safari, M and Khorshidi, A}, title = {Detection of VIM-1 and IMP-1 genes in Klebsiella pneumoniae and relationship with biofilm formation.}, journal = {Microbial pathogenesis}, volume = {115}, number = {}, pages = {25-30}, doi = {10.1016/j.micpath.2017.12.036}, pmid = {29248513}, issn = {1096-1208}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Child ; Child, Preschool ; Cross-Sectional Studies ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Multiple, Bacterial/genetics ; Female ; Gene Transfer, Horizontal ; Genes, Bacterial/*genetics ; Hospitals ; Humans ; Infant ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/*genetics/isolation & purification/*physiology ; Male ; Middle Aged ; Molecular Epidemiology ; Phenotype ; Urinary Tract Infections/microbiology ; Urine/microbiology ; Young Adult ; beta-Lactamases/*genetics ; }, abstract = {Klebsiella pneumoniae is an important human pathogen that is considered in recent years due to nosocomial infections resistant to treatment as well as the ability to form biofilms particularly in patients with urinary tract infection in ICU or hospital. The aim of this study was to evaluate the prevalence of VIM1, IMP1 genes and their ability to form biofilm in K. pneumoniae strains isolated from patients with urinary tract infection. In the study, using culture and biochemical methods, 1807 K. pneumoniae samples were isolated from patients with urinary tract infection hospitalized or referred to hospitals in Qom in 2013-2014. For isolation of MBL producing isolates, Double Disk Synergy Test (DDST) was used. Then MBL positive isolates were examined for the presence of VIM1, IMP1 genes using PCR method. Furthermore, all strains were investigated for biofilm formation by phenotypic microplate method. From 3165 urine samples cultured, 1807 isolates of K. pneumoniae were isolated and 109 strains (93.2%) were positive for MBL enzymes production. PCR results showed that the prevalence of VIM1 and IMP1 genes are 15.6 and 6.4%, respectively. The Phenotypic method indicated that 91.2% of isolates formed biofilm. Biofilm formation in K. pneumoniae isolates is high and there is a significant relationship between strong biofilm formation and prevalence of VIM1 and IMP1 genes. Also due to the presence of MBL genes in K. pneumoniae and horizontal transfer of genes to other bacteria, and to control the indiscriminate use of antibiotics, the hospital infection control methods must be considered.}, } @article {pmid29247704, year = {2018}, author = {Rout, B and Liu, CH and Wu, WC}, title = {Increased anti-biofilm efficacy of toluidine blue on Staphylococcus species after nano-encapsulation.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {190-200}, doi = {10.1016/j.pdpdt.2017.12.007}, pmid = {29247704}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Drug Delivery Systems/methods ; Emulsions/chemistry ; Nanoparticles/chemistry ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Staphylococcus/*drug effects ; Tolonium Chloride/administration & dosage/*pharmacology ; }, abstract = {BACKGROUND: Photodynamic therapy has been studied as a method for inactivating bacterial growth. Workers have used planktonic bacterial as well as biofilm bacterial cultures to evaluate the potential of photodynamic therapy in inactivating bacteria. However, almost all the studies use a photosensitiser in aqueous solution, which could be detrimental to the efficiency of photodynamic therapy.

METHODS: In this study, the photodynamic killing effect of toluidine blue O (TBO) has been investigated on Staphylococcal biofilms in-vitro. The sensitivity of the in-vitro biofilms to photodynamic killing action was compared using different formulations of TBO, different dosages of photosensitiser and different light irradiation strengths. Effect of TBO formulations on bacterial quorum sensing system was evaluated using a colorimetric assay. Finally, dual staining using hoechst and propidium iodide stains was carried out on the photodynamically treated biofilms to visualise and compare the effects of photodynamic therapy. Scanning electron microscope imagery was also carried out to evaluate the photodynamic killing effect on the in-vitro biofilms.

RESULTS: The sensitivity of biofilms to the photodynamic killing effect increased proportionally with the photosensitiser dosage and the light irradiation duration. TBO encapsulated in microemulsion was more effective in killing the biofilm bacteria than only TBO in water. The combination of TBO in microemulsion with EDTA was another effective way of increasing the photodynamic killing effect on the bacterial biofilms. Effect of encapsulated TBO on the quorum sensing system of bacteria was greater than the effect of aqueous solution of TBO. The in-vitro Staphylococcal biofilms could thus be inhibited by the photodynamic effect, and TBO encapsulated in microemulsion was much more effective than only TBO in water.

CONCLUSIONS: The encapsulation of a photosensitiser is an effective way of increasing the likelihood of the complete and successful inactivation of the biofilm growth. The encapsulated photosensitiser achieves higher inactivation of the bacterial biofilm than that of the aqueous solution of a photosensitiser.}, } @article {pmid29246799, year = {2018}, author = {Li, H and Goh, BN and Teh, WK and Jiang, Z and Goh, JPZ and Goh, A and Wu, G and Hoon, SS and Raida, M and Camattari, A and Yang, L and O'Donoghue, AJ and Dawson, TL}, title = {Skin Commensal Malassezia globosa Secreted Protease Attenuates Staphylococcus aureus Biofilm Formation.}, journal = {The Journal of investigative dermatology}, volume = {138}, number = {5}, pages = {1137-1145}, doi = {10.1016/j.jid.2017.11.034}, pmid = {29246799}, issn = {1523-1747}, mesh = {Aspartic Acid Proteases/physiology ; *Biofilms ; Humans ; Malassezia/*enzymology ; Peptide Hydrolases/*physiology ; Skin/*microbiology ; Staphylococcus aureus/*physiology ; }, abstract = {Skin provides the first defense against pathogenic micro-organisms and is also colonized by a diverse microbiota. Phylogenetic analysis of whole skin microbiome at different skin sites in health and disease has generated important insights on possible microbial involvement in modulating skin health. However, functional roles of the skin microbial community remain unclear. The most common sebaceous skin commensal yeasts are the basidiomycetes, Malassezia. Here, we characterized the dominant secreted Malassezia globosa protease in culture and subsequently named it Malassezia globosa Secreted Aspartyl Protease 1 (MgSAP1). We defined recombinant MgSAP1's substrate cleavage profile using an unbiased, mass-spectrometry-based technique. We show that this enzyme is physiologically relevant as mgsap1 expression was detected on at least one facial skin site of 17 healthy human volunteers. In addition, we demonstrated that this protease rapidly hydrolyzes Staphylococcus aureus protein A, an important S. aureus virulence factor involved in immune evasion and biofilm formation. We further observed that MgSAP1 has anti-biofilm properties against S. aureus. Taken together, our study defines a role for the skin fungus Malassezia in inter-kingdom interactions and suggests that this fungus and the enzymes it produces may be beneficial for skin health.}, } @article {pmid29244848, year = {2017}, author = {Zaltsman, N and Ionescu, AC and Weiss, EI and Brambilla, E and Beyth, S and Beyth, N}, title = {Surface-modified nanoparticles as anti-biofilm filler for dental polymers.}, journal = {PloS one}, volume = {12}, number = {12}, pages = {e0189397}, pmid = {29244848}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Composite Resins/chemistry/*pharmacology ; Compressive Strength ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Microbial Viability ; Nanoparticles ; Quaternary Ammonium Compounds/pharmacology ; Silicon Dioxide/chemistry/pharmacology ; Streptococcus mutans/drug effects/*physiology ; Surface Properties ; }, abstract = {The objective of the study was to synthesis silica nanoparticles modified with (i) a tertiary amine bearing two t-cinnamaldehyde substituents or (ii) dimethyl-octyl ammonium, alongside the well-studied quaternary ammonium polyethyleneimine nanoparticles. These were to be evaluated for their chemical and mechanical properties, as well for antibacterial and antibiofilm activity. Samples were incorporated in commercial dental resin material and the degree of monomer conversion, mechanical strength, and water contact angle were tested to characterize the effect of the nanoparticles on resin material. Antibacterial activity was evaluated with the direct contact test and the biofilm inhibition test against Streptococcus mutans. Addition of cinnamaldehyde-modified particles preserved the degree of conversion and compressive strength of the base material and increased surface hydrophobicity. Quaternary ammonium functional groups led to a decrease in the degree of conversion and to low compressive strength, without altering the hydrophilic nature of the base material. In the direct contact test and the anti-biofilm test, the polyethyleneimine particles exhibited the strongest antibacterial effect. The cinnamaldehyde-modified particles displayed antibiofilm activity, silica particles with quaternary ammonium were ineffective. Immobilization of t-cinnamaldehyde onto a solid surface via amine linkers provided a better alternative to the well-known quaternary ammonium bactericides.}, } @article {pmid29244484, year = {2018}, author = {Gupta, A and Das, R and Yesilbag Tonga, G and Mizuhara, T and Rotello, VM}, title = {Charge-Switchable Nanozymes for Bioorthogonal Imaging of Biofilm-Associated Infections.}, journal = {ACS nano}, volume = {12}, number = {1}, pages = {89-94}, pmid = {29244484}, issn = {1936-086X}, support = {R01 EB014277/EB/NIBIB NIH HHS/United States ; R01 EB022641/EB/NIBIB NIH HHS/United States ; R01 GM077173/GM/NIGMS NIH HHS/United States ; }, mesh = {Alkadienes/chemistry ; Animals ; *Biofilms ; Catalysis ; Escherichia coli/isolation & purification/*physiology ; Escherichia coli Infections/diagnosis/microbiology ; Fluorescent Dyes/*chemistry ; Gold/*chemistry ; Humans ; Hydrogen-Ion Concentration ; Ions/chemistry ; Metal Nanoparticles/*chemistry ; Mice ; Microscopy, Confocal/methods ; NIH 3T3 Cells ; Optical Imaging/*methods ; Ruthenium/*chemistry ; }, abstract = {Early detection of biofilms is crucial for limiting infection-based damage. Imaging these biofilms is challenging: conventional imaging agents are unable to penetrate the dense matrix of the biofilm, and many imaging agents are susceptible to false positive/negative responses due to phenotypical mutations of the constituent microbes. We report the creation of pH-responsive nanoparticles with embedded transition metal catalysts (nanozymes) that effectively target the acidic microenvironment of biofilms. These pH-switchable nanozymes generate imaging agents through bioorthogonal activation of profluorophores inside biofilms. The specificity of these nanozymes for imaging biofilms in complex biosystems was demonstrated using coculture experiments.}, } @article {pmid29243494, year = {2018}, author = {Yuksel, FN and Karatug, NT and Akcelik, M}, title = {Does subinhibitory concentrations of clinically important antibiotic induce biofilm production of Enterococcus faecium strains?.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {65}, number = {1}, pages = {27-38}, doi = {10.1556/030.64.2017.041}, pmid = {29243494}, issn = {1217-8950}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteremia/drug therapy/microbiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Enterococcus faecalis/*drug effects/genetics/isolation & purification/physiology ; Enterococcus faecium/*drug effects/genetics/isolation & purification/physiology ; Humans ; Microbial Sensitivity Tests ; Vancomycin/pharmacology ; }, abstract = {Biofilm structures are the most resistant form of active microorganisms against sanitation, disinfection, and sterilization processes. One of the specific properties of biofilm is the development of antibiotic resistance that can be up to 1,000-fold greater than planktonic cells. Enterococcus faecium is a human pathogen that causes nosocomial bacteremia and at the present time, it is well known that most of the chronic infections are biofilm-based. Recent evidence suggested that subinhibitory concentrations (sub-MICs) of antibiotics have an important role in the evolution of antibiotic resistance and induction on biofilm formation. Based on this information, we aimed to determine the effect of subinhibitory antibiotic concentrations on biofilm formation and the role of the antibiotic concentrations on the enterococcal surface protein gene (esp). To determine the impact of clinically important antibiotics on biofilm production, crystal violet assay was used. Then, the effect of sub-MICs of antibiotics on the expression of the esp gene was investigated by quantitative real-time PCR. Biofilm production assays show that MIC/2 of erythromycin (ERT; 512 μg/ml), MIC/32 of vancomycin (VAN; 16 μg/ml), MIC/64 of streptomycin (STR; 32 μg/ml), and MIC/128 of kanamycin (KAN; 4 μg/ml) values induce maximum biofilm production compared with the control. According to q-PCR results, sub-MIC values of ERT, VAN, and STR antibiotics were found to enhance esp gene expression. In addition, despite the increasing biofilm production after KAN treatment, the antibiotic was not effective on the esp expression.}, } @article {pmid29243151, year = {2018}, author = {Zeng, M and Hu, J and Wang, D and Wang, H and Wang, Y and Wu, N and Zhang, Z and Wang, C}, title = {Improving a compact biofilm reactor to realize efficient nitrogen removal performance: step-feed, intermittent aeration, and immobilization technique.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {7}, pages = {6240-6250}, pmid = {29243151}, issn = {1614-7499}, mesh = {Biofilms/*growth & development ; Bioreactors/*microbiology ; *Denitrification ; Models, Theoretical ; Nitrogen/*analysis ; Sewage/chemistry/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry/microbiology ; }, abstract = {Purifying tank as a compact biofilm reactor has been widely used to remove organic matter in rural sewage, but its potential for nitrogen removal is rare to be discussed. This study developed a lab-scale compact biofilm reactor to realize an efficient nitrogen removal performance by step-feed, intermittent aeration, and immobilization technique. The results show that an efficient simultaneous nitrification and denitrification (SND) process took place by feeding with synthetic wastewater under high C/N ratio of 2 and with real sewage as well, mainly due to the step-feed. The average removal efficiency of total inorganic nitrogen arrived at 72.7 and 63.3% for synthetic wastewater and real sewage, respectively. Besides the step-feed operation, the intermittent aeration was adopted to enhance SND, which allowed hydraulic behavior of compact biofilm reactor following the model of completely stirred tank reactor. The high-throughput sequencing analysis indicates that Sphaerotilus became the dominant genera with relative abundance of 30.29% under high C/N ratio, and the nitrifiers were not greatly inhibited. Moreover, the immobilization technique helped restore microbial activity under low temperature, promoting the satisfactory nitrogen removal performance of recovered microorganism to be rebuilt by feeding nutrient solution. Overall, the long-term SND process and maintaining effective biofilm activity can be established in the compact biofilm reactor through several improving alternatives.}, } @article {pmid29243115, year = {2018}, author = {Pirracchio, L and Joos, A and Luder, N and Sculean, A and Eick, S}, title = {Activity of taurolidine gels on ex vivo periodontal biofilm.}, journal = {Clinical oral investigations}, volume = {22}, number = {5}, pages = {2031-2037}, pmid = {29243115}, issn = {1436-3771}, mesh = {Anti-Infective Agents, Local/*therapeutic use ; Bacterial Load ; Biofilms/*drug effects ; Chlorhexidine/*therapeutic use ; Gels ; Humans ; In Vitro Techniques ; Periodontitis/*microbiology ; Taurine/*analogs & derivatives/therapeutic use ; Thiadiazines/*therapeutic use ; Treatment Outcome ; }, abstract = {OBJECTIVES: The purpose of this study is to evaluate the activity of two different taurolidine (TAU) gels in comparison with a 0.2% chlorhexidine (CHX) gel on an ex vivo subgingival biofilm.

MATERIAL AND METHODS: Subgingival including supragingival biofilm samples from periodontitis patients were cultured for 10 days, before TAU 1% and TAU 3% gels and CHX gel were applied for 10 min and thereafter diluted with nutrient media to 10% for 50 min. One third of the samples were analyzed for bacterial counts, biofilm quantity, and biofilm metabolic activity. In the two other thirds, 90% of the nutrient media were replaced and biofilms were incubated for 23 h. The second third was analyzed in the same way as before. In the third part, patients' microorganisms were added again and incubated for additional 24 h to allow reformation of biofilm before proceeding to analysis.

RESULTS: Decrease of bacterial counts in biofilms was highest following application of TAU 3% after 60 min (0.87 log10 cfu, corresponding 86.5%), 24 and 48 h (reformation of biofilms), respectively. All antimicrobials reduced biofilm quantity after 24 h (each p < 0.05) and following reformation of biofilms (each p < 0.01). Metabolic activity in biofilms was decreased at 60 min (each p < 0.05) and at 24 h (each p < 0.01) after application of TAU gels, while the activity of the reformed biofilm was lower after application of all evaluated antimicrobials (each p < 0.01) than in the control group (e.g., without exposure to antimicrobials).

CONCLUSION: The antimicrobial activity of taurolidine gels clearly depends on its taurolidine concentration. A high concentrated taurolidine gel is equally active or even superior to 0.2% chlorhexidine gel. However, the activity of antimicrobials is limited in a complex established biofilm and underlines the pivotal role of mechanical biofilm disruption.

CLINICAL RELEVANCE: Within their limits, the data suggest that TAU 3% gel might represent a potential alternative to 0.2% chlorhexidine gel.}, } @article {pmid29241218, year = {2018}, author = {Lee, J and Townsend, JA and Thompson, T and Garitty, T and De, A and Yu, Q and Peters, BM and Wen, ZT}, title = {Analysis of the Cariogenic Potential of Various Almond Milk Beverages using a Streptococcus mutans Biofilm Model in vitro.}, journal = {Caries research}, volume = {52}, number = {1-2}, pages = {51-57}, pmid = {29241218}, issn = {1421-976X}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cariogenic Agents/*adverse effects ; Milk/adverse effects ; *Milk Substitutes ; Prunus dulcis/*adverse effects ; Soy Milk ; Streptococcus mutans/*growth & development ; }, abstract = {To evaluate the cariogenic properties of almond milk beverages, 6 almond milks, along with soy and whole bovine milk, were analyzed for their abilities to support Streptococcus mutans biofilm formation and acid production, and their capacity to buffer changes in pH. Biofilm formation by S. mutans was analyzed using an in vitro 96-well plate model and measured by crystal violet staining. Acid production by S. mutans was evaluated by a colorimetric L-lactate assay and pH measurement of bacterial cultures. Buffering capacity was assessed by a pH titration assay. Soy milk supported the most biofilm growth, while the least was observed with unsweetened almond milk (both p < 0.001). Among almond milks, sucrose-sweetened milk led to the highest level of biofilm formation (p < 0.001), while the least was observed with unsweetened milk (p < 0.05). Sucrose-sweetened almond milk yielded the lowest pH (4.56 ± 0.66), followed by soy milk and bovine milk; the highest pH was with unsweetened almond milk (6.48 ± 0.5). When analyzed by pH titration, the unsweetened almond milk displayed the weakest buffering capacity while bovine milk showed the highest (p < 0.001). These results suggest that the almond milk beverages, except those that are sweetened with sucrose, possess limited cariogenic properties, while soy milk exhibits the most cariogenic potential. As milk alternatives become increasingly popular, dentists must counsel their patients that almond milks, especially sucrose-sweetened varieties, have cariogenic potential. For patients who are lactose-intolerant or suffer from milk allergy, almond milks may be a better alternative than soy-based products.}, } @article {pmid29241112, year = {2018}, author = {Lu, YZ and Chen, GJ and Bai, YN and Fu, L and Qin, LP and Zeng, RJ}, title = {Chromium isotope fractionation during Cr(VI) reduction in a methane-based hollow-fiber membrane biofilm reactor.}, journal = {Water research}, volume = {130}, number = {}, pages = {263-270}, doi = {10.1016/j.watres.2017.11.045}, pmid = {29241112}, issn = {1879-2448}, mesh = {Bacteria/metabolism ; Biofilms ; *Bioreactors ; Chemical Fractionation ; Chromium/*metabolism ; Chromium Isotopes/*chemistry ; Geologic Sediments/microbiology ; Methane/metabolism ; Oxidation-Reduction ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Chromium (Cr) isotope fractionation analysis is a promising tool for monitoring Cr(VI) reduction in natural aqueous systems. In addition, large amounts of CH4 in natural aqueous sediments are oxidized to CO2 through methanotrophs, thereby mitigating emissions to the atmosphere. However, the investigations on the Cr(VI) reduction process with methanotrophs, and the associated Cr isotope fractionation patterns are scarce. In this study, we have shown that Cr(VI) reduction can occur in the presence of CH4 as the sole electron donor in a hollow-fiber membrane reactor (HfMBR) after direct bacteria enrichment from sediment samples. Products of the methane oxidation by the methanotrophs are used by microbes to reduce Cr(VI) as shown by the progressive increase in δ[53]Cr with time in the CH4 feed reactor. The isotope fractionation factor (ε) of -2.62 ± 0.20‰ was obtained from the application of the Rayleigh distillation model. The results of Cr isotope fractionation analysis also explained the decrease of Cr(VI) concentration in the N2 feed reactor, where the δ[53]Cr values remained steady in the first two weeks but significantly increased in the last two weeks, indicating that physical adsorption and subsequent Cr(VI) reduction occurred. This study extended the application of Cr isotope fractionation, showing the suitability of this method for clarifying different Cr(VI) removal processes.}, } @article {pmid29240873, year = {2018}, author = {Brindle, CT and Porter, S and Bijlani, K and Arumugam, S and Matias, R and Najafi, R and Fisher, J}, title = {Preliminary Results of the Use of a Stabilized Hypochlorous Acid Solution in the Management of Ralstonia Pickettii Biofilm on Silicone Breast Implants.}, journal = {Aesthetic surgery journal}, volume = {38}, number = {suppl_2}, pages = {S52-S61}, doi = {10.1093/asj/sjx229}, pmid = {29240873}, issn = {1527-330X}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/drug effects ; Breast Implantation/adverse effects/instrumentation ; Breast Implants/adverse effects/*microbiology ; Humans ; Hypochlorous Acid/*administration & dosage ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/etiology/microbiology/prevention & control ; Ralstonia pickettii/*drug effects/isolation & purification/physiology ; Silicone Gels ; }, abstract = {BACKGROUND: Ralstonia Pickettii biofilms are associated with pocket infections following breast implant surgeries. Biofilm protects bacteria most topically applied antimicrobial irrigations.

OBJECTIVES: To evaluate the effectiveness of four antimicrobial solutions on the planktonic form and established biofilm of Ralstonia Pickettii grown on 3 different types of silicone breast implants.

METHODS: Time kill assays at clinical concentrations of chlorhexidine gluconate, povidone iodine, triple-antibiotic solution, and a 0.025% hypochlorous acid solution stabilized in amber glass were evaluated. Normal saline was the control. Three types of silicone implants, two with a textured surface and one smooth surface, were selected. Planktonic assays were performed after implants were soaked for one, five, 30, and 120 minute time points. Biofilm assays were performed after 5 and 120 minutes of implant soak time. Both tests evaluated cell-forming units (CFU/mL).

RESULTS: Triple antibiotic solution had no effect on R. pickettii and was dropped from the study. Remaining solutions showed total kill of planktonic bacteria at one minute. Saline control showed no significant effect on biofilm as anticipated. Stabilized hypochlorous acid was the only solution tested capable of eradicating R. pickettii biofilm on all implant surfaces tested within the first five minute soak time.

CONCLUSIONS: Noncytotoxic, 0.025% hypochlorous acid in normal saline, stabilized in amber glass, successfully eradicated Ralstonia pickettii in planktonic and mature biofilm on three types of silicone implants during initial five minute soak time and may be the preferred antimicrobial solution for pocket lavage. This preliminary study requires further investigation. Leaching and implant compatibility testing is currently in progress.}, } @article {pmid29238454, year = {2017}, author = {Mousavi, SF and Mirzaei, B and Shaghaghi, B and Jalali, P and Setayesh, T and Moosavi, SH}, title = {Phenotypic and genotypic features of first biofilm forming nasopharyngeal colonized Streptococcus pneumoniae isolates.}, journal = {Iranian journal of microbiology}, volume = {9}, number = {4}, pages = {200-207}, pmid = {29238454}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Designing control and therapeutic policies for antibiotic resistant Streptococcus pneumoniae, which is an important causative agent of several invasive and noninvasive infectious diseases and its carriage rates, has been described as the main target in World Health Organization (WHO). The present study was conducted to determine antibiotic resistance pattern, evaluate biofilm forming ability in S. pneumoniae isolates, and find the genetic relationship between cultured strains.

MATERIALS AND METHODS: Following the isolation and identification of S. pneumoniae strains from nasopharyngeal swabs, the ability of biofilm formation and susceptibility pattern of the isolates were screened using semi-quantitative microplate and disk diffusion procedures. Subsequently, Pulse field gel electrophoresis (PFGE) method was used to determine the clonal diversity of isolates.

RESULTS: The pneumococcal colonization rate in this study was found to be 24%. A large number of our isolates had strong biofilm forming ability. However, there was variation in antibiotic resistance patterns of isolates in children who lived in nursery houses. The genetic similarity among the isolates in PFGE varied from 26.5% to 100% in our isolates. This was the first report of biofilm formation of nasopharyngeal colonized S. pneumoniae in Iran. Genetic variations were also noticeable, when the isolates were fingerprinted by PFGE.

CONCLUSION: The findings of this study revealed the need for thoughtful use of antimicrobial agents, continued monitoring of pneumococcal resistance patterns, and prevention of the spread of multi-drug resistant clones.}, } @article {pmid29238284, year = {2017}, author = {Park, HJ and Han, SW}, title = {Functional and Proteomic Analyses Reveal That ScpBXv Is Involved in Bacterial Growth, Virulence, and Biofilm Formation in Xanthomonas campestris pv. vesicatoria.}, journal = {The plant pathology journal}, volume = {33}, number = {6}, pages = {602-607}, pmid = {29238284}, issn = {1598-2254}, abstract = {Segregation and condensation protein B (ScpB) is essential for replication and segregation in living organisms. Here, we reported the functions of ScpBXv (ScpB-like protein in Xanthomonas campestris pv. vesicatoria) using phenotypic and proteomic analyses. Growth of XcvΔscpBXv (ScpBXv knockout mutant) was reduced under both slow and fast growth conditions in rich medium, but comparable to this of the wild-type in plant-mimic conditions. Interestingly, the mutant was significantly less virulent than the wild-type in tomato, indicating that ScpBXv is involved in virulence. To investigate ScpBXv-associated mechanisms, comparative proteomic analyses were carried out and the abundance of 187 proteins was altered. Among them, diverse transcriptional regulators involved in biofilm formation and virulence were abundant in the wild-type. We further showed that biofilm formation of XcvΔscpBXv was reduced. This study provides new insights into the functions of ScpBXv in bacterial replication and biofilm formation, which may contribute to the virulence of Xcv.}, } @article {pmid29237244, year = {2018}, author = {Valdebenito, B and Tullume-Vergara, PO and González, W and Kreth, J and Giacaman, RA}, title = {In silico analysis of the competition between Streptococcus sanguinis and Streptococcus mutans in the dental biofilm.}, journal = {Molecular oral microbiology}, volume = {33}, number = {2}, pages = {168-180}, doi = {10.1111/omi.12209}, pmid = {29237244}, issn = {2041-1014}, mesh = {Bacterial Proteins/*genetics/*metabolism ; Bacteriocins/metabolism ; *Biofilms ; Computer Simulation ; Databases, Genetic ; Dental Caries/microbiology ; Dental Plaque/*microbiology ; Genes, Bacterial/genetics ; Gluconeogenesis ; Humans ; Hydrogen Peroxide/metabolism ; Metabolic Networks and Pathways ; Mouth/microbiology ; Streptococcus mutans/*genetics/*metabolism ; Streptococcus sanguis/*genetics/*metabolism ; }, abstract = {During dental caries, the dental biofilm modifies the composition of the hundreds of involved bacterial species. Changing environmental conditions influence competition. A pertinent model to exemplify the complex interplay of the microorganisms in the human dental biofilm is the competition between Streptococcus sanguinis and Streptococcus mutans. It has been reported that children and adults harbor greater numbers of S. sanguinis in the oral cavity, associated with caries-free teeth. Conversely, S. mutans is predominant in individuals with a high number of carious lesions. Competition between both microorganisms stems from the production of H2 O2 by S. sanguinis and mutacins, a type of bacteriocins, by S. mutans. There is limited evidence on how S. sanguinis survives its own H2 O2 levels, or if it has other mechanisms that might aid in the competition against S. mutans, nonetheless. We performed a genomic and metabolic pathway comparison, coupled with a comprehensive literature review, to better understand the competition between these two species. Results indicated that S. sanguinis can outcompete S. mutans by the production of an enzyme capable of metabolizing H2 O2 . S. mutans, however, lacks the enzyme and is susceptible to the peroxide from S. sanguinis. In addition, S. sanguinis can generate energy through gluconeogenesis and seems to have evolved different communication mechanisms, indicating that novel proteins may be responsible for intra-species communication.}, } @article {pmid29236012, year = {2017}, author = {Saidi, A and Masmoudi, K and Nolde, E and El Amrani, B and Amraoui, F}, title = {Organic matter degradation in a greywater recycling system using a multistage moving bed biofilm reactor (MBBR).}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {76}, number = {11-12}, pages = {3328-3339}, doi = {10.2166/wst.2017.499}, pmid = {29236012}, issn = {0273-1223}, mesh = {Berlin ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Disinfection ; Filtration/methods ; Germany ; Recycling/*methods ; Silicon Dioxide ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical ; Water Purification/methods ; }, abstract = {Greywater is an important non-conventional water resource which can be treated and recycled in buildings. A decentralized greywater recycling system for 223 inhabitants started operating in 2006 in Berlin, Germany. High load greywater undergoes advanced treatment in a multistage moving bed biofilm reactor (MBBR) followed by sand filtration and UV disinfection. The treated water is used safely as service water for toilet flushing. Monitoring of the organic matter degradation was pursued to describe the degradation processes in each stage and optimize the system. Results showed that organic matter reduction was achieved for the most part in the first three reactors, whereas the highest reduction rate was observed in the third reactor in terms of COD (chemical oxygen demand), dissolved organic carbon and BOD7 (biological oxygen demand). The results also showed that the average loading rate entering the system was 3.7 kg COD/d, while the removal rate was 3.4 kg COD/d in a total bioreactor volume of 11.7 m[3]. In terms of BOD, the loading rate was 2.8 kg BOD/d and it was almost totally removed. This system requires little space (0.15 m[2]/person) and maintenance work of less than one hour per month and it shows operational stability under peak loads.}, } @article {pmid29235503, year = {2017}, author = {Jain, S and Smyth, D and O'Hagan, BMG and Heap, JT and McMullan, G and Minton, NP and Ternan, NG}, title = {Inactivation of the dnaK gene in Clostridium difficile 630 Δerm yields a temperature-sensitive phenotype and increases biofilm-forming ability.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {17522}, pmid = {29235503}, issn = {2045-2322}, support = {G0601176/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms ; Clostridioides difficile/*growth & development/*metabolism/ultrastructure ; Escherichia coli ; Gene Expression Regulation ; Gene Knockout Techniques ; *Molecular Chaperones/genetics/metabolism ; Movement/physiology ; Mutation ; Phenotype ; Temperature ; }, abstract = {Clostridium difficile infection is a growing problem in healthcare settings worldwide and results in a considerable socioeconomic impact. New hypervirulent strains and acquisition of antibiotic resistance exacerbates pathogenesis; however, the survival strategy of C. difficile in the challenging gut environment still remains incompletely understood. We previously reported that clinically relevant heat-stress (37-41 °C) resulted in a classical heat-stress response with up-regulation of cellular chaperones. We used ClosTron to construct an insertional mutation in the dnaK gene of C. difficile 630 Δerm. The dnaK mutant exhibited temperature sensitivity, grew more slowly than C. difficile 630 Δerm and was less thermotolerant. Furthermore, the mutant was non-motile, had 4-fold lower expression of the fliC gene and lacked flagella on the cell surface. Mutant cells were some 50% longer than parental strain cells, and at optimal growth temperatures, they exhibited a 4-fold increase in the expression of class I chaperone genes including GroEL and GroES. Increased chaperone expression, in addition to the non-flagellated phenotype of the mutant, may account for the increased biofilm formation observed. Overall, the phenotype resulting from dnaK disruption is more akin to that observed in Escherichia coli dnaK mutants, rather than those in the Gram-positive model organism Bacillus subtilis.}, } @article {pmid29235402, year = {2018}, author = {Del Pozo, JL}, title = {Biofilm-related disease.}, journal = {Expert review of anti-infective therapy}, volume = {16}, number = {1}, pages = {51-65}, doi = {10.1080/14787210.2018.1417036}, pmid = {29235402}, issn = {1744-8336}, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bacteria/*drug effects/growth & development/isolation & purification ; Bacterial Infections/drug therapy/microbiology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Bacterial ; Humans ; Recurrence ; }, abstract = {Biofilm formation represents a protected mode of growth that renders bacterial cells less susceptible to antimicrobials and to killing by host immune effector mechanisms and so enables the pathogens to survive in hostile environments and also to disperse and colonize new niches. Biofilm disease includes device-related infections, chronic infections in the absence of a foreign body, and even malfunction of medical devices. Areas covered: This review puts forward a new medical entity that represents a major public health issue, which we have named 'biofilm-related disease'. We highlight the characteristics of biofilm disease including its pathogenesis, microbiological features, clinical presentation, and treatment challenges. Expert commentary: The diversity of biofilm-associated infections is increasing over time and its impact may be underestimated. This peculiar form of development endows associated bacteria with a high tolerance to conventional antimicrobial agents. A small percentage of persister cells developing within the biofilm is known to be highly tolerant to antibiotics and has typically been involved in causing relapse of infections. Knowledge of the pivotal role played by biofilm-growing microorganisms in related infections will provide new treatment dynamics for this biofilm-related disease.}, } @article {pmid29234974, year = {2018}, author = {Dižová, S and Černáková, L and Bujdáková, H}, title = {The impact of farnesol in combination with fluconazole on Candida albicans biofilm: regulation of ERG20, ERG9, and ERG11 genes.}, journal = {Folia microbiologica}, volume = {63}, number = {3}, pages = {363-371}, pmid = {29234974}, issn = {1874-9356}, support = {APVV-15-0347//Slovak Research and Development Agency/ ; 1/0628/15//VEGA/ ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/*growth & development ; Dose-Response Relationship, Drug ; Drug Synergism ; Ergosterol/genetics/metabolism ; Farnesol/*pharmacology ; Fluconazole/*pharmacology ; Gene Expression Regulation, Fungal/*drug effects ; Genes, Fungal/genetics ; Hyphae/drug effects ; Metabolic Networks and Pathways/drug effects ; Microbial Sensitivity Tests ; }, abstract = {Farnesol (FAR) has already demonstrated an inhibitory effect on Candida albicans biofilm. The aim of this work was to determine the effectiveness of externally added FAR in combination with fluconazole (FLC) on Candida albicans biofilm and on regulation of the ergosterol genes ERG20, ERG9, and ERG11. The effectiveness of compounds was determined by MTT assay and evaluated by the minimal inhibitory concentrations reducing a sessile biofilm to 50% activity (0.5 μg/mL and 200 μmol/L for FLC and FAR, respectively). These concentrations as well as 30 and 100 μmol/L FAR were selected for a study of the effectiveness of the FAR/FLC combination. The reduction in biofilm robustness mainly caused by the presence of 200 μmol/L FAR-alone or in combination with FLC-was accompanied by a significant inhibition of the yeast-to-hyphae transition that was observed by light microscopy and CLSM. Results from qRT-PCR indicated that while 30 μmol/L FAR only slightly regulated the expression of all 3 genes in the 48-h biofilm, the presence of 200 μmol/L FAR downregulated all the tested genes. However, the addition of 0.5 μg/mL of FLC to the samples with 200 μmol/L FAR restored the downregulation of the ERG20 and ERG11 genes to the control level. Moreover, the gene ERG9 was slightly upregulated. In summary, FAR acted via multiple effects on the C. albicans biofilm, but only a higher concentration of FAR proved to be effective.}, } @article {pmid29234307, year = {2017}, author = {Shi, C and Yan, C and Sui, Y and Sun, Y and Guo, D and Chen, Y and Jin, T and Peng, X and Ma, L and Xia, X}, title = {Thymoquinone Inhibits Virulence Related Traits of Cronobacter sakazakii ATCC 29544 and Has Anti-biofilm Formation Potential.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2220}, pmid = {29234307}, issn = {1664-302X}, abstract = {The aim of this study was to determine whether thymoquinone, the principal active ingredient in the volatile oil of Nigella sativa seeds, could suppress certain virulence traits of Cronobacter sakazakii ATCC 29544 which contribute to infection. Sub-inhibitory concentrations of thymoquinone significantly decreased motility, quorum sensing, and endotoxin production of C. sakazakii ATCC 29544 and biofilm formation of C. sakazakii 7-17. Thymoquinone substantially reduced the adhesion and invasion of C. sakazakii ATCC 29544 to HT-29 cells and decreased the number of intracellular bacterial cells within the RAW 264.7 macrophage cells. Thymoquinone also repressed the transcription of sixteen genes involved in the virulence. These findings suggest that thymoquinone could attenuated virulence-related traits of C. sakazakii ATCC 29544, and its effects on other C. sakazakii strains and in vivo C. sakazakii infection need further investigation.}, } @article {pmid29234121, year = {2017}, author = {Head, D and A Devine, D and Marsh, PD}, title = {In silico modelling to differentiate the contribution of sugar frequency versus total amount in driving biofilm dysbiosis in dental caries.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {17413}, pmid = {29234121}, issn = {2045-2322}, mesh = {*Biofilms/growth & development ; Computer Simulation ; Dental Caries/*metabolism/*microbiology ; Dental Plaque/metabolism/microbiology ; Dietary Sucrose/*adverse effects ; Dysbiosis/*metabolism ; Glycolysis ; Humans ; Hydrogen-Ion Concentration ; Models, Biological ; Saliva/metabolism ; }, abstract = {Dental caries is the most prevalent infection globally and a substantial economic burden in developed countries. Dietary sugars are the main risk factor, and drive increased proportions of acid-producing and acid-tolerating (aciduric) bacterial species within dental biofilms. Recent longitudinal studies have suggested that caries is most strongly correlated with total sugar intake, contrasting with the prevailing view that intake frequency is the primary determinant. To explore this possibility, we employed a computational model for supragingival plaque to systematically sample combinations of sugar frequency and total amount, allowing their independent contributions on the ratio of aciduric (i.e. cariogenic) to non-aciduric bacteria to be unambiguously determined. Sugar frequency was found to be irrelevant for either very high or very low daily total amounts as the simulated biofilm was predicted to be always or never cariogenic, respectively. Frequency was a determining factor for intermediate total amounts of sugar, including the estimated average human consumption. An increased risk of caries (i.e. high prevalence of aciduric/non-aciduric species) was predicted for high intake frequencies. Thus, both total amount and frequency of sugar intake may combine to influence plaque cariogenicity. These findings could be employed to support public guidance for dietary change, leading to improved oral healthcare.}, } @article {pmid29234086, year = {2017}, author = {Costa, F and Sousa, DM and Parreira, P and Lamghari, M and Gomes, P and Martins, MCL}, title = {N-acetylcysteine-functionalized coating avoids bacterial adhesion and biofilm formation.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {17374}, pmid = {29234086}, issn = {2045-2322}, mesh = {Acetylcysteine/*chemistry/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Chitosan/chemistry ; *Coated Materials, Biocompatible ; Materials Testing ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Surface Properties ; }, abstract = {N-acetyl cysteine (NAC) is an FDA-approved drug clinically applied on a broad range of pathologies. Further research has been conducted with this drug to benefit from its antimicrobial activity potential. However, NAC has a very short half-life and therefore strategies that accomplish high local concentrations would be beneficial. In this study, covalent immobilization of NAC was performed, in order to obtain long-lasting high local concentration of the drug onto a chitosan(Ch)-derived implant-related coating. For the development of NAC-functionalized Ch films, water-based carbodiimide chemistry was applied to avoid the use of toxic organic solvents. Here we report the optimization steps performed to immobilize NAC onto the surface of pre-prepared Ch coatings, to ensure full exposure of NAC. Surface characterization using ellipsometry, water contact angle measurements and X-ray photoelectron spectroscopy (XPS), demonstrated the success of NAC immobilization at 4 mg/mL. Quartz crystal microbalance with dissipation (QCM-D) demonstrated that surface immobilized NAC decreases protein adsorption to Ch coatings. Biological studies confirmed that immobilized NAC4 avoids methicillin-resistant Staphylococcus aureus adhesion to Ch coating, impairing biofilm formation, without inducing cytotoxic effects. This is particularly interesting towards further developments as a prevention coating.}, } @article {pmid29233780, year = {2018}, author = {Abraham, R and Prakash, P and Mahendran, K and Ramanathan, M}, title = {A novel series of N-acyl substituted indole-linked benzimidazoles and naphthoimidazoles as potential anti inflammatory, anti biofilm and anti microbial agents.}, journal = {Microbial pathogenesis}, volume = {114}, number = {}, pages = {409-413}, doi = {10.1016/j.micpath.2017.12.021}, pmid = {29233780}, issn = {1096-1208}, mesh = {Anti-Infective Agents/*chemical synthesis/*pharmacology ; Anti-Inflammatory Agents/*chemical synthesis/*pharmacology ; Benzimidazoles/*chemical synthesis/*pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Indoles/*chemical synthesis/*pharmacology ; Magnetic Resonance Spectroscopy ; Microbial Sensitivity Tests ; Molecular Structure ; }, abstract = {A novel N-acyl substituted indole-linked benzimidazoles and naphthoimidazoles were synthesized. Their chemical structures were confirmed using spectroscopic tools including [1]H NMR, [13]C NMR and CHN-elemental analyses. Anti inflammatory activity for all target compounds was evaluated in-vitro. The synthesized compounds hinder the biofilm formation and control the growth of the pathogen, Staphylococcus epidermis. Anti microbial activity of the compounds was evaluated against both Gram negative and Gram positive bacteria such as Staphylococcus aureus (MTCC 2940), Pseudomonas aeruginosa (MTCC424), Escherchia coli (MTCC 443) and Enterococcus fecalis.}, } @article {pmid29233187, year = {2017}, author = {Bregnocchi, A and Zanni, E and Uccelletti, D and Marra, F and Cavallini, D and De Angelis, F and De Bellis, G and Bossù, M and Ierardo, G and Polimeni, A and Sarto, MS}, title = {Graphene-based dental adhesive with anti-biofilm activity.}, journal = {Journal of nanobiotechnology}, volume = {15}, number = {1}, pages = {89}, pmid = {29233187}, issn = {1477-3155}, support = {2016//ATENEO Sapienza/ ; }, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Dental Cements/*chemistry/pharmacology ; Graphite/*chemistry ; Microscopy, Electron, Scanning ; Nanostructures/chemistry ; Oxidative Stress/drug effects ; Rheology ; Streptococcus mutans/*physiology ; Tensile Strength ; }, abstract = {BACKGROUND: Secondary caries are considered the main cause of dental restoration failure. In this context, anti-biofilm and bactericidal properties are desired in dental materials against pathogens such as Streptococcus mutans. To this purpose, graphene based materials can be used as fillers of polymer dental adhesives. In this work, we investigated the possibility to use as filler of dental adhesives, graphene nanoplatelets (GNP), a non toxic hydrophobic nanomaterial with antimicrobial and anti-biofilm properties.

RESULTS: Graphene nanoplatelets have been produced starting from graphite intercalated compounds through a process consisting of thermal expansion and liquid exfoliation. Then, a dental adhesive filled with GNPs at different volume fractions has been produced through a solvent evaporation method. The rheological properties of the new experimental adhesives have been assessed experimentally. The adhesive properties have been tested using microtensile bond strength measurements (µ-TBS). Biocidal activity has been studied using the colony forming units count (CFU) method. The anti-biofilm properties have been demonstrated through FE-SEM imaging of the biofilm development after 3 and 24 h of growth.

CONCLUSIONS: A significantly lower vitality of S. mutans cells has been demonstrated when in contact with the GNP filled dental adhesives. Biofilm growth on adhesive-covered dentine tissues demonstrated anti-adhesion properties of the produced materials. µ-TBS results demonstrated no significant difference in µ-TBS between the experimental and the control adhesive. The rheology tests highlighted the necessity to avoid low shear rate regimes during adhesive processing and application in clinical protocol, and confirmed that the adhesive containing the 0.2%wt of GNPs possess mechanical properties comparable with the ones of the control adhesive.}, } @article {pmid29232959, year = {2018}, author = {Oder, M and Arlič, M and Bohinc, K and Fink, R}, title = {Escherichia coli biofilm formation and dispersion under hydrodynamic conditions on metal surfaces.}, journal = {International journal of environmental health research}, volume = {28}, number = {1}, pages = {55-63}, doi = {10.1080/09603123.2017.1415309}, pmid = {29232959}, issn = {1369-1619}, mesh = {Biofilms/*growth & development ; Escherichia coli/*physiology ; Hydrodynamics ; *Stainless Steel ; }, abstract = {The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E. coli, and biofilm formation and dispersion. The experiments were provided in a flow chamber simulating a cleaning-in-place system. Biofilm biomass was measured using a crystal violet dye method. The results show that hydrodynamic forces affect not only biofilm formation and dispersion but the multiplication of E. coli in the first place. We found more biofilm biomass on the rough surface than on the smooth one. The results of the biofilm formation test show that laminar flow promotes the biofilm growth over 72 h, meanwhile turbulent flow after 48 h causes decrease in biomass. The results of the biofilm dispersion test, in contrast, show that laminar flow removed less biofilm from both materials that turbulent flow did. Therefore, taking into account these findings in cleaning-in-place technology can substantially reduce E. coli multiplication and biofilm formation.}, } @article {pmid29231866, year = {2017}, author = {Sønderholm, M and Bjarnsholt, T and Alhede, M and Kolpen, M and Jensen, PØ and Kühl, M and Kragh, KN}, title = {The Consequences of Being in an Infectious Biofilm: Microenvironmental Conditions Governing Antibiotic Tolerance.}, journal = {International journal of molecular sciences}, volume = {18}, number = {12}, pages = {}, pmid = {29231866}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Cystic Fibrosis/microbiology ; Humans ; Lung/drug effects/*microbiology/pathology ; Models, Biological ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/drug effects/*physiology ; }, abstract = {The main driver behind biofilm research is the desire to understand the mechanisms governing the antibiotic tolerance of biofilm-growing bacteria found in chronic bacterial infections. Rather than genetic traits, several physical and chemical traits of the biofilm have been shown to be attributable to antibiotic tolerance. During infection, bacteria in biofilms exhibit slow growth and a low metabolic state due to O2 limitation imposed by intense O2 consumption of polymorphonuclear leukocytes or metabolically active bacteria in the biofilm periphery. Due to variable O2 availability throughout the infection, pathogen growth can involve aerobic, microaerobic and anaerobic metabolism. This has serious implications for the antibiotic treatment of infections (e.g., in chronic wounds or in the chronic lung infection of cystic fibrosis patients), as antibiotics are usually optimized for aerobic, fast-growing bacteria. This review summarizes knowledge about the links between the microenvironment of biofilms in chronic infections and their tolerance against antibiotics.}, } @article {pmid29231844, year = {2017}, author = {Lee, JH and Kim, E and Choi, H and Lee, J}, title = {Collismycin C from the Micronesian Marine Bacterium Streptomyces sp. MC025 Inhibits Staphylococcus aureus Biofilm Formation.}, journal = {Marine drugs}, volume = {15}, number = {12}, pages = {}, pmid = {29231844}, issn = {1660-3397}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests/methods ; Staphylococcal Infections/*drug therapy ; Streptomyces/*chemistry ; }, abstract = {Biofilm formation plays a critical role in antimicrobial resistance in Staphylococcus aureus. Here, we investigated the potential of crude extracts of 79 Micronesian marine microorganisms to inhibit S. aureus biofilm formation. An extract of Streptomyces sp. MC025 inhibited S. aureus biofilm formation. Bioactivity-guided isolation led to the isolation of a series of 2,2'-bipyridines: collismycin B (1), collismycin C (2), SF2738 D (3), SF2738 F (4), pyrisulfoxin A (5), and pyrisulfoxin B (6). Among these bipyridines, collismycin C (2) was found to be the most effective inhibitor of biofilm formation by methicillin-sensitive S. aureus and methicillin-resistant S. aureus (MRSA), and this compound inhibited MRSA biofilm formation by more than 90% at a concentration of 50 μg/mL. The antibiofilm activity of collismycin C was speculated to be related to iron acquisition and the presence and position of the hydroxyl group of 2,2'-bipyridines.}, } @article {pmid29230970, year = {2018}, author = {Devaraj, A and Buzzo, J and Rocco, CJ and Bakaletz, LO and Goodman, SD}, title = {The DNABII family of proteins is comprised of the only nucleoid associated proteins required for nontypeable Haemophilus influenzae biofilm structure.}, journal = {MicrobiologyOpen}, volume = {7}, number = {3}, pages = {e00563}, pmid = {29230970}, issn = {2045-8827}, support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Chinchilla ; DNA-Binding Proteins/*metabolism ; Disease Models, Animal ; Ear, Middle/microbiology ; Haemophilus Infections/microbiology ; Haemophilus influenzae/*growth & development/*metabolism ; Integration Host Factors/*metabolism ; Otitis Media/microbiology ; }, abstract = {Biofilms play a central role in the pathobiology of otitis media (OM), bronchitis, sinusitis, conjunctivitis, and pneumonia caused by nontypeable Haemophilus influenzae (NTHI). Our previous studies show that extracellular DNA (eDNA) and DNABII proteins are essential components of biofilms formed by NTHI. The DNABII protein family includes integration host factor (IHF) and the histone-like protein HU and plays a central role in NTHI biofilm structural integrity. We demonstrated that immunological targeting of these proteins during NTHI-induced experimental OM in a chinchilla model caused rapid clearance of biofilms from the middle ear. Given the essential role of DNABII proteins in maintaining the structure of an NTHI biofilm, we investigated whether any of the other nucleoid associated proteins (NAPs) expressed by NTHI might play a similar role, thereby serving as additional target(s) for intervention. We demonstrated that although several NAPs including H-NS, CbpA, HfQ and Dps are present within the biofilm extracellular matrix, only the DNABII family of proteins is critical for the structural integrity of the biofilms formed by NTHI. We have also demonstrated that IHF and HU are located at distinct regions within the extracellular matrix of NTHI biofilms formed in vitro, indicative of independent functions of these two proteins.}, } @article {pmid29230206, year = {2017}, author = {Jia, R and Yang, D and Xu, D and Gu, T}, title = {Anaerobic Corrosion of 304 Stainless Steel Caused by the Pseudomonas aeruginosa Biofilm.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2335}, pmid = {29230206}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a ubiquitous bacterium capable of forming problematic biofilms in many environments. They cause biocorrosion of medical implants and industrial equipment and infrastructure. Aerobic corrosion of P. aeruginosa against stainless steels has been reported by some researchers while there is a lack of reports on anaerobic P. aeruginosa corrosion in the literature. In this work, the corrosion by a wild-type P. aeruginosa (strain PAO1) biofilm against 304 stainless steel (304 SS) was investigated under strictly anaerobic condition for up to 14 days. The anaerobic corrosion of 304 SS by P. aeruginosa was reported for the first time. Results showed that the average sessile cell counts on 304 SS coupons after 7- and 14-day incubations were 4.8 × 10[7] and 6.2 × 10[7] cells/cm[2], respectively. Scanning electron microscopy and confocal laser scanning microscopy corroborated the sessile cell counts. The X-ray diffraction analysis identified the corrosion product as iron nitride, confirming that the corrosion was caused by the nitrate reducing biofilm. The largest pit depths on 304 SS surfaces after the 7- and 14-day incubations with P. aeruginosa were 3.9 and 7.4 μm, respectively. Electrochemical tests corroborated the pitting data.}, } @article {pmid29228383, year = {2018}, author = {Chevalier, M and Ranque, S and Prêcheur, I}, title = {Oral fungal-bacterial biofilm models in vitro: a review.}, journal = {Medical mycology}, volume = {56}, number = {6}, pages = {653-667}, doi = {10.1093/mmy/myx111}, pmid = {29228383}, issn = {1460-2709}, mesh = {Bacteria/*classification/growth & development ; Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Candida/*classification/growth & development/physiology ; Coculture Techniques ; Humans ; Microbial Consortia/*physiology ; *Models, Biological ; Mouth/*microbiology ; Streptococcus mutans/growth & development/physiology ; }, abstract = {Inclusion of fungi as commensals in oral biofilm is an important innovation in oral biology, and this work aimed to review the literature on the available biofilm and related disease in vitro models. Actually, thousands of bacterial and around one hundred of fungal phylotypes can colonize the oral cavity. Taxonomic profiling combined with functional expression analysis has revealed that Candida albicans, Streptococcus mutans and prominent periodontopathogens are not always present or numerically important in candidiasis, caries, or periodontitis lesions. However, C. albicans combined with Streptococcus spp. co-increase their virulence in invasive candidiasis, early childhood caries or peri-implantitis. As Candida species and many other fungi are also members of oral microcosms in healthy individuals, mixed fungal-bacterial biofilm models are increasingly valuable investigative tools, and new fungal-bacterial species combinations need to be investigated. Here we review the key points and current methods for culturing in vitro mixed fungal-bacterial models of oral biofilms. According to ecosystem under study (health, candidiasis, caries, periodontitis), protocol design will select microbial strains, biofilm support (polystyrene plate, cell culture, denture, tooth, implant), pre-treatment support (human or artificial saliva) and culture conditions. Growing mixed fungal-bacterial biofilm models in vitro is a difficult challenge. But reproducible models are needed, because oral hygiene products, food and beverage, medication, licit and illicit drugs can influence oral ecosystems. So, even though most oral fungi and bacteria are not cultivable, in vitro microbiological models should still be instrumental in adapting oral care products, dietary products and care protocols to patients at higher risk of oral diseases. Microbial biofilm models combined with oral epithelial cell cultures could also aid in understanding the inflammatory reaction.}, } @article {pmid29228246, year = {2018}, author = {Monfredini, PM and Souza, ACR and Cavalheiro, RP and Siqueira, RA and Colombo, AL}, title = {Clinical impact of Candida spp. biofilm production in a cohort of patients with candidemia.}, journal = {Medical mycology}, volume = {56}, number = {7}, pages = {803-808}, doi = {10.1093/mmy/myx133}, pmid = {29228246}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Candida/classification/genetics/*growth & development/isolation & purification ; Candidemia/*microbiology/*pathology ; Cohort Studies ; DNA, Fungal/chemistry/genetics ; DNA, Ribosomal Spacer/chemistry/genetics ; Gentian Violet/metabolism ; Humans ; Microbiological Techniques ; Microscopy, Confocal ; Sequence Analysis, DNA ; Staining and Labeling ; }, abstract = {Persistent candidemia refers to the continued isolation of the same Candida species in the blood of a candidemic patient despite appropriate therapy. Despite the clinical importance of persistent candidemia, studies have superficially addressed the biological conditions behind this phenomenon. The aim of this study was to evaluate the correlation between the biofilm-forming ability by Candida bloodstream isolates and the persistence of infection. A total of 55 isolates of Candida were tested and characterized in two groups: (i) group I, which included seven patients with persistent candidemia, and (ii) group II, which included 18 patients with nonpersistent candidemia. Microorganisms were identified at the species level by sequencing the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). Biofilm quantification was evaluated by the crystal violet staining method and confocal scanning laser microscopy (CSLM). Molecular tests confirmed the identification of Candida albicans (92% group I and 94% group II) and Candida dubliniensis isolates (8% group I and 6% group II). All 55 isolates were able to form biofilms, but a higher biofilm mass was produced by C. albicans/C. dubliniensis strains cultured from the persistent group (P < .05). Our data suggest that Candida sp. biofilm production should be considered a relevant biologic variable in explaining patients who fail to clear a bloodstream infection despite adequate antifungal treatment with triazoles.}, } @article {pmid29225755, year = {2017}, author = {Vahedi, M and Hosseini-Jazani, N and Yousefi, S and Ghahremani, M}, title = {Evaluation of anti-bacterial effects of nickel nanoparticles on biofilm production by Staphylococcus epidermidis.}, journal = {Iranian journal of microbiology}, volume = {9}, number = {3}, pages = {160-168}, pmid = {29225755}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus epidermidis produces biofilm by extracellular polysaccharides, causing bacterial adherence to different surfaces. Anti-microbial effects of nickel nanoparticles on some bacterial strains such as S. aureus and Escherichia coli have been determined in limited studies. The aim of the present study is to examine the inhibitory effect of nickel nanoparticles on biofilm formation using clinical isolates of S. epidermidis and its hemolytic effect on human red blood cells.

MATERIALS AND METHODS: Twenty two S. epidermidis isolates were collected and identified by standard microbiological methods. Microtiter plate method was used to determine the biofilm production in bacterial isolates. The amounts of biofilm formation by isolates in the presence of 0.01, 0.05, 0.1, and 1 mg/mL concentrations of nickel nanoparticles were measured. Hemolytic activity of different concentrations of nickel nanoparticles was measured on human RBC suspensions.

RESULTS: Twenty isolates were strong, and two isolates were moderate biofilm producers. Biofilm formation significantly decreased in the presence of 0.05, 0.1, and 1 mg/mL of nickel nanoparticles (p<0.05). Although in the presence of 0.01 mg/mL of nickel nanoparticles, decrease in biofilm formation was observed but it was not statistically significant (p=0.448). Slight hemolytic activity was seen in the presence of nickel nanoparticles.

CONCLUSION: In this study, the ability of biofilm production was demonstrated for all clinical isolates of S. epidermidis. On the other hand, the lowering effects of nickel nanoparticles on biofilm formation were observed.}, } @article {pmid29225595, year = {2017}, author = {Zheng, JX and Wu, Y and Lin, ZW and Pu, ZY and Yao, WM and Chen, Z and Li, DY and Deng, QW and Qu, D and Yu, ZJ}, title = {Characteristics of and Virulence Factors Associated with Biofilm Formation in Clinical Enterococcus faecalis Isolates in China.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2338}, pmid = {29225595}, issn = {1664-302X}, abstract = {Enterococcus faecalis biofilm traits and distribution characteristics in China have not been clarified. This study aimed to determine the prevalence and characteristics of E. faecalis biofilm formation in a sample of clinical isolates and to explore the virulence factors associated with biofilm formation in those isolates. A total of 265 E. faecalis isolates were collected from patients in Shenzhen, China. Virulence genes were detected within the genomes of the microbes by polymerase chain reaction. The isolates were subjected to multilocus sequence typing (MLST) based on housekeeping genes. Biofilms were detected by crystal violet staining. The expression levels of the clinical E. faecalis isolates' genes were determined by quantitative real-time polymerase chain reaction. The prevalence of biofilm formation among E. faecalis clinical isolates was 47.2%. MLST yielded 44 different sequence types (STs). The main STs were ST16 and ST179; the ST16 isolates were more likely to form strong or medium biofilm than the ST179 isolates (p < 0.001). Strong or medium biofilm formation was more common in linezolid-resistant isolates than in linezolid-sensitive isolates (p = 0.001). Biofilm formation was more frequently detected in enterococcal surface protein (esp+), surface aggregating protein (asa1+), cytolysin A (cylA+), or aggregation substance (agg+) positive isolates than in isolates that were negative (-) for these virulence factors. Multivariate regression analysis indicated that cylA [odds ratio (OR) 4.083, p < 0.001] was a risk factor for weak biofilm formation, and that esp (OR 8.207, p < 0.001) was a risk factor for strong or medium biofilm formation. The expression of cylA was raised (4.02 to 6.00-fold) in weak biofilm isolates compared to the biofilm-negative isolates, and the expression of esp was greatly elevated (11.39 to 134.08-fold) in strong biofilm isolates compared to biofilm-negative isolates. In conclusion, the ST16 classification and linezolid resistance were positively associated with strong/medium biofilm formation in clinical E. faecalis isolates. cylA was associated with weak biofilm formation, and esp was only associated with strong or medium biofilm formation of the clinical E. faecalis isolates.}, } @article {pmid29225413, year = {2017}, author = {Alipour, N and Karagoz, A and Taner, A and Gaeini, N and Alipour, N and Zeytin, H and Yildiz, F and Durmaz, R}, title = {Outbreak of Hospital Infection from Biofilm-embedded Pan Drug-resistant Pseudomonas aeroginosa, Due to a Contaminated Bronchoscope.}, journal = {Journal of preventive medicine}, volume = {2}, number = {2}, pages = {}, pmid = {29225413}, issn = {2572-5483}, abstract = {BACKGROUND: Colistin-resistant Pseudomonas aeruginosa (P. aeruginosa) has been defined as pandrug-resistant (PDR) strain. Outbreaks of PDR P. aeruginosa especially in pulmonary tract infections due to contaminated bronchoscopes have rarely been reported. The emergence of pandrug-resistant strains in both CF (Cystic Fibrosis) and non-CF clinical isolates over recent years remains of a great concern. Hospital wards contaminated with PDR P. aeruginosa infection, must be shot down until their eradication. Health Authorities must be informed immediately and infection control strategies must be implemented.

AIM: To report such an outbreak and modify the infection control strategy in an academic hospital in Ankara Turkey.

METHODS: From October to December 2013, PDR-Pseudomonas aerogionsa were identified from bronchial cultures of 15 patients who had undergone bronchoscopy prior to the infection. Three batches of surveillance cultures were obtained from the environmental objects and healthcare workers related to the procedures. Pulsed-field gel electrophoresis (PFGE) was used for bacterial typing. Antimicrobial susceptibility was assessed by disc diffusion and E-test methods.

FINDINGS: A total of 70 specimens were obtained during the first surveillance operation. One Colistin-resistant P. aeroginosa was isolated from a bronchoscope. Although the disinfection protocols for bronchoscope were revised and implemented, seven additional bronchial cases were identified thereafter. The pathogen was identified from two subsequent surveillance cultures and was not eliminated until Ethylene oxide sterilization was added to the disinfection protocol. PFGE revealed that all 15 isolates from the patients and the three isolates from the bronchoscope shared a common pattern with minor variance. XbaI restriction enzyme turned out better than SpeI in interpreting bacterial pulse types with BioNumerics 6.0. The most suitable cut off value for SpeI was above 80% Dice similarity while for XbaI above 95%Dice similarity with BioNumerics 6.0.

CONCLUSION: The outbreak of "Colistin" pan drug-resistant Pseudomonas aeroginosa was caused by a contaminated bronchoscope and was terminated by the implementation of a revised disinfection protocol for bronchoscope.}, } @article {pmid29224997, year = {2018}, author = {Pérez-Granda, MJ and Alonso, B and Rodríguez-Huerta, A and Rodríguez, C and Guembe, M}, title = {In vitro assessment of the anti-biofilm activity of ethanol alone and in combination with enoxaparin 60IU.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {36}, number = {10}, pages = {627-632}, doi = {10.1016/j.eimc.2017.11.007}, pmid = {29224997}, issn = {2529-993X}, mesh = {Anti-Infective Agents, Local/*administration & dosage/pharmacology ; Anticoagulants/*administration & dosage ; Biofilms/*drug effects ; Drug Combinations ; Enoxaparin/*administration & dosage/pharmacology ; Ethanol/*administration & dosage/pharmacology ; Microbiological Techniques ; }, abstract = {INTRODUCTION: Catheter-related bloodstream infection (C-RBSI) can sometimes be managed without catheter removal by combining systemic therapy with catheter lock therapy. Most antiseptic lock solutions are made up of ethanol combined with an anticoagulant. However, data regarding the anti-biofilm activity of ethanol combined with enoxaparin are scarce. We aimed to assess the efficacy of ethanol at different concentrations combined with enoxaparin 60IU as a lock solution for eradication of the biofilm of different microorganisms.

METHODS: Using a static 96-well plate in vitro model, we tested 30%, 35%, and 40% ethanol alone and combined with 60IU of enoxaparin against 24-h-old biofilm from the following microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, and Candida albicans. Time of exposure was assessed during a 2-h and 24-h regimen. We analysed the percentage reduction in metabolic activity using the XTT assay. We considered therapy to be successful when metabolic activity was reduced by >90%.

RESULTS: In the 2-h regimen, the therapy was successful against all microorganisms at 35% and 40% ethanol without enoxaparin (p<0.001). In the 24-h regimen, the therapy was successful against all microorganisms at all ethanol solutions without enoxaparin (p<0.001). When ethanol was combined with enoxaparin, the therapy was only successful in the 24-h regimen in biofilms of S. epidermidis, C. albicans and E. coli at all concentrations of ethanol assessed.

CONCLUSIONS: Our in vitro model demonstrated that when ethanol is combined with enoxaparin in a lock solution, it negatively affects ethanol anti-biofilm activity after both short and long exposures.}, } @article {pmid29224767, year = {2017}, author = {Grønseth, T and Vestby, LK and Nesse, LL and Thoen, E and Habimana, O and von Unge, M and Silvola, JT}, title = {Lugol's solution eradicates Staphylococcus aureus biofilm in vitro.}, journal = {International journal of pediatric otorhinolaryngology}, volume = {103}, number = {}, pages = {58-64}, doi = {10.1016/j.ijporl.2017.09.025}, pmid = {29224767}, issn = {1872-8464}, mesh = {Acetic Acid/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Boric Acids/*pharmacology ; Iodides/*pharmacology ; Microscopy, Confocal ; Staphylococcus aureus/*drug effects ; }, abstract = {OBJECTIVES: The aim of the study was to evaluate the antibacterial efficacy of Lugol's solution, acetic acid, and boric acid against Staphylococcus aureus biofilm.

METHODS: The efficacy of Lugol's solution 1%, 0.1%, and 0.05%, acetic acid 5% or boric acid 4.7% for treatment of Staphylococcus aureus biofilm in vitro was tested using 30 clinical strains. Susceptibility in the planktonic state was assessed by disk diffusion test. Antiseptic effect on bacteria in biofilm was evaluated by using a Biofilm-oriented antiseptic test (BOAT) based on metabolic activity, a biofilm bactericidal test based on culturing of surviving bacteria and confocal laser scanning microscopy combined with LIVE/DEAD staining.

RESULTS: In the planktonic state, all tested S. aureus strains were susceptible to Lugol's solution and acetic acid, while 27 out of 30 tested strains were susceptible to boric acid. In biofilm the metabolic activity was significantly reduced following exposure to Lugol's solution and 5% acetic acid, while boric acid exposure led to no significant changes in metabolic activities. In biofilm, biocidal activity was observed for Lugol's solution 1% (30/30), 0.1% (30/30), and 0.05% (26/30). Acetic acid and boric acid showed no bactericidal activity in this test. Confocal laser scanning microscopy, assessed in 4/30 strains, revealed significantly fewer viable biofilm bacteria with Lugol's solution (1% p < 0.001, 0.1% p = 0.001 or 0.05% p = 0.001), acetic acid 5% for 10 min (p = 0.001) or 30 min (p = 0.015), but not for acetic acid for 1 min or boric acid.

CONCLUSION: Lugol's solution 1.0% and 0.1% effectively eradicated S. aureus in biofilm and could be an alternative to conventional topical antibiotics where S. aureus biofilm is suspected such as external otitis, pharyngitis and wounds.}, } @article {pmid29224124, year = {2018}, author = {Lv, ZH and Wang, J and Yang, GF and Feng, LJ and Mu, J and Zhu, L and Xu, XY}, title = {Underestimated effects of sediments on enhanced startup performance of biofilm systems for polluted source water pretreatment.}, journal = {Biodegradation}, volume = {29}, number = {1}, pages = {89-103}, doi = {10.1007/s10532-017-9815-8}, pmid = {29224124}, issn = {1572-9729}, support = {LQ17E090002//Natural Science Foundation of Zhejiang Province of China/International ; No. Q1601//Scientific Research Launching Project of Zhejiang Ocean University/International ; YMJH201606//Yumiao Talent Project of Zhejiang Ocean University/International ; 2017ZJSHKF02//Key Laboratory of Water Pollution Control and Environmental Safety of Zhejiang Province, China/International ; }, mesh = {Bacteria/metabolism ; Batch Cell Culture Techniques ; Biodegradation, Environmental ; *Biofilms ; Bioreactors/microbiology ; Denitrification ; Geologic Sediments/*chemistry ; Nitrification ; Nitrogen/metabolism ; Phylogeny ; Principal Component Analysis ; Water Pollutants/isolation & purification ; Water Pollution/*analysis ; Water Purification/*methods ; }, abstract = {In order to evaluate the enhancement mechanisms of enhanced startup performance in biofilm systems for polluted source water pretreatment, three lab-scale reactors with elastic stereo media (ESM) were operated under different enhanced sediment and hydraulic agitation conditions. It is interesting to found the previously underestimated or overlooked effects of sediment on the enhancement of pollutants removal performance and enrichment of functional bacteria in biofilm systems. The maximum NH4[+]-N removal rate of 0.35 mg L[-1] h[-1] in sediment enhanced condition was 2.19 times of that in control reactor. Sediment contributed to 42.0-56.5% of NH4[+]-N removal and 15.4-41.2% of total nitrogen removal in different reactors under different operation conditions. The enhanced hydraulic agitation with sediment further improved the operation performance and accumulation of functional bacteria. Generally, Proteobacteria (48.9-52.1%), Bacteroidetes (18.9-20.8%) and Actinobacteria (15.7-18.5%) were dominant in both sediment and ESM bioiflm at phylum level. The potentially functional bacteria found in sediment and ESM biofilm samples with some functional bacteria mainly presented in sediment samples only (e.g., Genera Bacillus and Lactococcus of Firmicutes phylum) may commonly contribute to the removal of nitrogen and organics.}, } @article {pmid29221859, year = {2018}, author = {Pinto, AP and Rosseti, IB and Carvalho, ML and da Silva, BGM and Alberto-Silva, C and Costa, MS}, title = {Photodynamic Antimicrobial Chemotherapy (PACT), using Toluidine blue O inhibits the viability of biofilm produced by Candida albicans at different stages of development.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {182-189}, doi = {10.1016/j.pdpdt.2017.12.001}, pmid = {29221859}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects ; Cell Survival ; Humans ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Reactive Oxygen Species ; Tolonium Chloride/*pharmacology ; }, abstract = {BACKGROUND: Candida albicans is an opportunistic fungus producing both superficial and systemic infections, especially in immunocompromised individuals. It has been demonstrated that C. albicans ability to form biofilms is a crucial process for colonization and virulence. Furthermore, a correlation between the development of drug resistance and biofilm maturation at Candida biofilms has been shown. Photodynamic Antimicrobial Chemotherapy (PACT) is a potential antimicrobial therapy that combines visible light and a non-toxic dye, known as a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells. The objective of this study was to investigate the effects of PACT, using Toluidine Blue O (TBO) on the viability of biofilms produced by C. albicans at different stages of development.

METHODS: In this study, the effects of PACT on both biofilm formation and viability of the biofilm produced by C. albicans were studied. Biofilm formation and viability were determined by a metabolic assay based on the reduction of XTT assay. In addition, the morphology of the biofilm was observed using light microscopy.

RESULTS: PACT inhibited both biofilm formation and viability of the biofilm produced by C. albicans. Furthermore, PACT was able to decrease the number of both cells and filamentous form present in the biofilm structure. This inhibitory effect was observed in both early and mature biofilms.

CONCLUSIONS: The results obtained in this study demonstrated the potential of PACT (using TBO) as an effective antifungal therapy, including against infections associated with biofilms at different stages of development.}, } @article {pmid29218030, year = {2017}, author = {Quintas, V and Prada-López, I and Carreira, MJ and Suárez-Quintanilla, D and Balsa-Castro, C and Tomás, I}, title = {In Situ Antibacterial Activity of Essential Oils with and without Alcohol on Oral Biofilm: A Randomized Clinical Trial.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2162}, pmid = {29218030}, issn = {1664-302X}, support = {U17 CE002010/CE/NCIPC CDC HHS/United States ; }, abstract = {Currently, there is little evidence on the in situ antibacterial activity of essential oils (EO) without alcohol. This study aimed to evaluate in situ the substantivity and antiplaque effect on the plaque-like biofilm (PL-biofilm) of two solutions, a traditional formulation that contains EO with alcohol (T-EO) and an alcohol-free formulation of EO (Af-EO). Eighteen healthy adults performed a single mouthwash of: T-EO, Af-EO, and sterile water (WATER) after wearing an individualized disk-holding splint for 2 days. The bacterial viability (BV) and thickness of the PL-biofilm were quantified at baseline, 30 s, and 1, 3, 5, and 7 h post-rinsing (Test 1). Subsequently, each volunteer wore the splint for 4 days, applying two daily mouthwashes of: T-EO, Af-EO, and WATER. The BV, thickness, and covering grade (CG) of the PL-biofilm were quantified (Test 2). Samples were analyzed by confocal laser scanning microscopy after staining with the LIVE/DEAD® BacLight™ solution. To conduct the computations of the BV automatically, a Matlab toolbox called Dentius Biofilm was developed. In test 1, both EO antiseptics had a similar antibacterial effect, reducing BV after a single rinse compared to the WATER, and keeping it below baseline levels up to 7 h post-rinse (P < 0.001). The mean thickness of the PL-biofilm after rinsing was not affected by any of the EO formulations and ranged from 18.58 to 20.19 μm. After 4 days, the T-EO and Af-EO solutions were significantly more effective than the WATER, reducing the BV, thickness, and CG of the PL-biofilm (P < 0.001). Although, both EO antiseptics presented a similar bactericidal activity, the Af-EO rinses led to more significant reductions in the thickness and CG of the PL-biofilm than the T-EO rinses (thickness = 7.90 vs. 9.92 μm, P = 0.012; CG = 33.36 vs. 46.61%, P = 0.001). In conclusion, both essential oils antiseptics had very high immediate antibacterial activity and substantivity in situ on the 2-day PL-biofilm after a single mouthwash. In the 4-day PL-biofilm, both essential oils formulations demonstrated a very good antiplaque effect in situ, although the alcohol-free formula performed better at reducing the biofilm thickness and covering grade.}, } @article {pmid29216517, year = {2018}, author = {Wang, X and Han, Q and Yu, N and Wang, T and Wang, C and Yang, R}, title = {GO-AgCl/Ag nanocomposites with enhanced visible light-driven catalytic properties for antibacterial and biofilm-disrupting applications.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {162}, number = {}, pages = {296-305}, doi = {10.1016/j.colsurfb.2017.11.060}, pmid = {29216517}, issn = {1873-4367}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/radiation effects ; Catalysis ; Cell Survival/drug effects ; Graphite/chemistry/*pharmacology ; Light ; Metal Nanoparticles/*chemistry/radiation effects/ultrastructure ; Mice ; NIH 3T3 Cells ; Nanocomposites/*chemistry/radiation effects/ultrastructure ; Oxides ; Photochemical Processes ; Silver Compounds/chemistry/*pharmacology ; Staphylococcus aureus/*drug effects/growth & development/radiation effects ; }, abstract = {Nanomaterials with visible light-driven photocatalytic activity have attracted much attention due to their excellent abilities in degradation of various organic pollutants as well as inactivating bacteria. Herein, graphene oxide (GO) enwrapped silver chloride/silver (AgCl/Ag) nanocomposites with high visible light absorption were designed and fabricated as efficient antibacterial agents. AgCl NPs were synthesized in the presence of GO first and Ag NPs were coated on AgCl surface by heat reduction to form GO-AgCl/Ag nanocomposites. The as prepared nanocomposites revealed improved stability, higher absorption properties in the visible light region. The enhanced antibacterial activity was observed by quantification of colony forming units (CFU) and morphological changes of bacteria. The antibacterial mechanism of GO-AgCl/Ag was also investigated by evaluating membrane permeability and ROS level. Moreover, GO-AgCl/Ag composites can eliminate bacterial biofilms more efficiently under visible light irradiation. Our results provide new insights into the design of new multifunctional systems for antibacterial applications.}, } @article {pmid29216511, year = {2018}, author = {Romero, CM and Martorell, PV and López, AG and Peñalver, CGN and Chaves, S and Mechetti, M}, title = {Architecture and physicochemical characterization of Bacillus biofilm as a potential enzyme immobilization factory.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {162}, number = {}, pages = {246-255}, doi = {10.1016/j.colsurfb.2017.11.057}, pmid = {29216511}, issn = {1873-4367}, mesh = {Adsorption ; Bacillus/*chemistry ; Biocatalysis ; *Biofilms ; DNA, Bacterial/*chemistry ; Elasticity ; Enzyme Stability ; Enzymes, Immobilized/*chemistry ; Fructans/*chemistry ; Green Chemistry Technology ; Hydrogen-Ion Concentration ; Hydrophobic and Hydrophilic Interactions ; Lipase/*chemistry ; Rheology ; Surface Properties ; Viscosity ; }, abstract = {Biocatalysis for industrial application is based on the use of enzymes to perform complex transformations. However, these systems have some disadvantage related to the costs of the biocatalyst. In this work, an alternative strategy for producing green immobilized biocatalysts based on biofilm was developed.A study of the rheological behavior of the biofilm from Bacillus sp. Mcn4, as well as the determination of its composition, was carried out. The dynamic rheological measurements, viscosity (G") and elasticity (G') module, showed that the biofilm presents appreciable elastic components, which is a recognized property for enzymes immobilization. After the partial purification, the exopolysaccharidewas identified as a levan with a non-Newtonian behavior. Extracellular DNA with fragments between 10,000 and 1000bp was detected also in the biofilm, and amyloid protein in the extracellular matrix using a fluorescence technique was identified. Bacillus sp. Mcn4 biofilms were developed on different surfaces, being the most stable those developed on hydrophilic supports. The biofilm showed lipase activity suggesting the presence of constitutive lipases entrapped into the biofilm. Indeed, two enzymes with lipase activity were identified in native PAGE. These were used as biocatalysts, whose reuse showed a residual lipase activity after more than one cycle of catalysis. The components identified in the biofilm could be the main contributors of the rheological characteristic of this material, giving an exceptional environment to the lipase enzyme. Based on these findings, the current study proposes green and natural biopolymers matrix as support for the enzyme immobilization for industrial applications.}, } @article {pmid29215358, year = {2017}, author = {Gulati, P and Ghosh, M}, title = {Biofilm forming ability of Sphingomonas paucimobilis isolated from community drinking water systems on plumbing materials used in water distribution.}, journal = {Journal of water and health}, volume = {15}, number = {6}, pages = {942-954}, doi = {10.2166/wh.2017.294}, pmid = {29215358}, issn = {1477-8920}, mesh = {Biofilms/*growth & development ; Drinking Water/*microbiology ; *Sanitary Engineering ; Sphingomonas/growth & development/*physiology ; *Water Supply ; }, abstract = {Sphingomonas paucimobilis, an oligotroph, is well recognized for its potential for biofilm formation. The present study explored the biofilm forming ability of a strain isolated from municipal drinking water on plumbing materials. The intensity of biofilm formation of this strain on different plumbing materials was examined by using 1 × 1 cm[2] pieces of six different pipe materials, i.e. polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), aluminium (Al), copper (Cu) and rubber (R) and observing by staining with the chemical chromophore, Calcofluor. To understand whether biofilm formation occurs under flow through conditions, a laboratory-scale simulated distribution system, comprised of the above materials was fabricated. Biofilm samples were collected from the designed system at different biofilm ages (10, 40 and 90 hours old) and enumerated. The results indicated that the biofilm formation occurred on all plumbing materials with Cu and R as exceptions. The intensity of biofilm formation was found to be maximum on PVC followed by PP and PE. We also demonstrated the chemical chromophore (Calcofluor) successfully for rapid and easy visual detection of biofilms, validated by scanning electron microscope (SEM) analysis of the plumbing materials. Chlorination has little effect in preventing biofilm development.}, } @article {pmid29215356, year = {2017}, author = {Jarząb, N and Walczak, M}, title = {The presence of biofilm forming microorganisms on hydrotherapy equipment and facilities.}, journal = {Journal of water and health}, volume = {15}, number = {6}, pages = {923-931}, doi = {10.2166/wh.2017.025}, pmid = {29215356}, issn = {1477-8920}, mesh = {Bacteria/isolation & purification ; *Bacterial Physiological Phenomena ; *Biofilms ; *Equipment Contamination ; *Hydrotherapy ; Poland ; Temperature ; }, abstract = {Hydrotherapy equipment provides a perfect environment for the formation and growth of microbial biofilms. Biofilms may reduce the microbiological cleanliness of hydrotherapy equipment and harbour opportunistic pathogens and pathogenic bacteria. The aims of this study were to investigate the ability of microorganisms that colonize hydrotherapy equipment to form biofilms, and to assess the influence of temperature and nutrients on the rate of biofilm formation. Surface swab samples were collected from the whirlpool baths, inhalation equipment and submerged surfaces of a brine pool at the spa center in Ciechocinek, Poland. We isolated and identified microorganisms from the swab samples and measured their ability to form biofilms. Biofilm formation was observed at a range of temperatures, in both nutrient-deficient and nutrient-rich environments. We isolated and identified microorganisms which are known to form biofilms on medical devices (e.g. Stenotrophomonas maltophilia). All isolates were classified as opportunistic pathogens, which can cause infections in humans with weakened immunity systems. All isolates showed the ability to form biofilms in the laboratory conditions. The potential for biofilm formation was higher in the presence of added nutrients. In addition, the hydrolytic activity of the biofilm was connected with the presence of nutrients.}, } @article {pmid29215338, year = {2017}, author = {Kart, D and Kustimur, AS and Sağıroğlu, M and Kalkancı, A}, title = {Evaluation of Antimicrobial Durability and Anti-Biofilm Effects in Urinary Catheters Against Enterococcus faecalis Clinical Isolates and Reference Strains.}, journal = {Balkan medical journal}, volume = {34}, number = {6}, pages = {546-552}, pmid = {29215338}, issn = {2146-3131}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/*microbiology/prevention & control ; Catheters, Indwelling/*microbiology ; Coated Materials, Biocompatible ; Enterococcus faecalis/*drug effects/isolation & purification ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Nitrofurazone/*pharmacology ; Silicones ; Silver ; Urinary Catheterization/adverse effects ; Urinary Tract Infections/*microbiology/prevention & control ; }, abstract = {BACKGROUND: Enterococcus faecalis, Escherichia coli, Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans biofilms are major causes of catheter-associated urinary tract infections. Antimicrobial-coated or impregnated urinary catheters are seen as a possible way to prevent these infections.

AIMS: To determine the biofilm-forming ability of 89 E. faecalis isolates from urinary tract infections and to compare several urinary catheters for antimicrobial durability and the inhibitory effects on biofilm formation of different laboratory strains and clinical isolates of E. faecalis.

STUDY DESIGN: In vitro experimental study.

METHODS: The biofilm forming ability of E. faecalis isolates was determined by the crystal violet staining and plate counting methods. For comparison of urinary catheters, biofilms of 45 E. faecalis isolates from the catheter samples of hospitalized patients and five laboratory strains of E. coli ATCC25922, S. epidermidis ATCC35984, P. aeruginosa ATCC27853, E. faecalis ATCC29212 and C. albicans ATCC90028 were formed on the catheters in 24-well tissue culture plates. Scanning electron microscopy analysis was performed to observe biofilms.

RESULTS: All 89 E. faecalis isolates were found to be biofilm positive. Nitrofurazone-impregnated catheters significantly reduced the cell counts of E. faecalis isolates and completely inhibited the formation of P. aeruginosa and S. epidermidis biofilms compared with the others. Regarding reduction of biofilm cell counts, a hydrophilic-coated catheter was more effective against P. aeruginosa, whereas a silver-coated catheter was found to be more effective against S. epidermidis. The nitrofurazone-impregnated catheter had the best antimicrobial durability.

CONCLUSION: Urine isolates of E. faecalis had considerable ability with respect to biofilm formation. The nitrofurazone-impregnated catheter was the most effective against all tested bacteria; however, the effect of a hydrophilic or silver-coated catheter depends on the species present in it.}, } @article {pmid29215019, year = {2017}, author = {Zhu, B and Ge, X and Stone, V and Kong, X and El-Rami, F and Liu, Y and Kitten, T and Xu, P}, title = {ciaR impacts biofilm formation by regulating an arginine biosynthesis pathway in Streptococcus sanguinis SK36.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {17183}, pmid = {29215019}, issn = {2045-2322}, support = {R01 DE018138/DE/NIDCR NIH HHS/United States ; R01 DE023078/DE/NIDCR NIH HHS/United States ; }, mesh = {Arginine/*metabolism ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; *Metabolic Networks and Pathways ; *Mutation ; Streptococcus sanguis/genetics/*growth & development/metabolism ; }, abstract = {Streptococcus sanguinis is an early colonizer of the tooth surface and competes with oral pathogens such as Streptococcus mutans to maintain oral health. However, little is known about its mechanism of biofilm formation. Here, we show that mutation of the ciaR gene, encoding the response regulator of the CiaRH two-component system in S. sanguinis SK36, produced a fragile biofilm. Cell aggregation, gtfP gene expression and water-insoluble glucan production were all reduced, which suggested polysaccharide production was decreased in ΔciaR. RNA sequencing and qRT-PCR revealed that arginine biosynthesis genes (argR, argB, argC, argG, argH and argJ) and two arginine/histidine permease genes (SSA_1568 and SSA_1569) were upregulated in ΔciaR. In contrast to ΔciaR, most of strains constructed to contain deletions in each of these genes produced more biofilm and water-insoluble glucan than SK36. A ΔciaRΔargB double mutant was completely restored for the gtfP gene expression, glucan production and biofilm formation ability that was lost in ΔciaR, indicating that argB was essential for ciaR to regulate biofilm formation. We conclude that by promoting the expression of arginine biosynthetic genes, especially argB gene, the ciaR mutation reduced polysaccharide production, resulting in the formation of a fragile biofilm in Streptococcus sanguinis.}, } @article {pmid29214046, year = {2017}, author = {Drewes, JL and White, JR and Dejea, CM and Fathi, P and Iyadorai, T and Vadivelu, J and Roslani, AC and Wick, EC and Mongodin, EF and Loke, MF and Thulasi, K and Gan, HM and Goh, KL and Chong, HY and Kumar, S and Wanyiri, JW and Sears, CL}, title = {High-resolution bacterial 16S rRNA gene profile meta-analysis and biofilm status reveal common colorectal cancer consortia.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {34}, pmid = {29214046}, issn = {2055-5008}, support = {P50 CA062924/CA/NCI NIH HHS/United States ; P30 CA006973/CA/NCI NIH HHS/United States ; P30 DK089502/DK/NIDDK NIH HHS/United States ; R01 CA151393/CA/NCI NIH HHS/United States ; R01 CA196845/CA/NCI NIH HHS/United States ; S10 OD016374/OD/NIH HHS/United States ; }, abstract = {Colorectal cancer (CRC) remains the third most common cancer worldwide, with a growing incidence among young adults. Multiple studies have presented associations between the gut microbiome and CRC, suggesting a link with cancer risk. Although CRC microbiome studies continue to profile larger patient cohorts with increasingly economical and rapid DNA sequencing platforms, few common associations with CRC have been identified, in part due to limitations in taxonomic resolution and differences in analysis methodologies. Complementing these taxonomic studies is the newly recognized phenomenon that bacterial organization into biofilm structures in the mucus layer of the gut is a consistent feature of right-sided (proximal), but not left-sided (distal) colorectal cancer. In the present study, we performed 16S rRNA gene amplicon sequencing and biofilm quantification in a new cohort of patients from Malaysia, followed by a meta-analysis of eleven additional publicly available data sets on stool and tissue-based CRC microbiota using Resphera Insight, a high-resolution analytical tool for species-level characterization. Results from the Malaysian cohort and the expanded meta-analysis confirm that CRC tissues are enriched for invasive biofilms (particularly on right-sided tumors), a symbiont with capacity for tumorigenesis (Bacteroides fragilis), and oral pathogens including Fusobacterium nucleatum, Parvimonas micra, and Peptostreptococcus stomatis. Considered in aggregate, species from the Human Oral Microbiome Database are highly enriched in CRC. Although no detected microbial feature was universally present, their substantial overlap and combined prevalence supports a role for the gut microbiota in a significant percentage (>80%) of CRC cases.}, } @article {pmid29214000, year = {2017}, author = {Taghadosi, R and Shakibaie, MR and Ghanbarpour, R and Hosseini-Nave, H}, title = {Role of antigen-43 on biofilm formation and horizontal antibiotic resistance gene transfer in non-O157 Shiga toxin producing Escherichia coli strains.}, journal = {Iranian journal of microbiology}, volume = {9}, number = {2}, pages = {89-96}, pmid = {29214000}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: The objectives of this study were to evaluate the antibiotic resistance profiles, biofilm formation, presence of antigen 43 (Ag43) gene, and transfer of antibiotic resistance phenotype among non-O157 Shiga toxin producing Escherichia coli (STEC).

MATERIALS AND METHODS: From October 2014 to November 2015 a total of 276 stool samples were collected from healthy calves, goats and 395 patients with the sign of nonbloody diarrhea and screened for presence of stx and serotype O157 genes by polymerase chain reaction (PCR) technique. Susceptibility to 14 antibiotics was determined as per CLSI guideline. Presence of Ag43 and intimin (eaeA) genes were detected by PCR. Biofilm formation was measured by microtiter plate method. Conjugation was carried out by membrane filter technique.

RESULTS: We isolated 74 (93.6%) non-O157 STEC strains from 41 calves, 33 goats and 5 (6.3%) patients' stools, however, no O157 serotype was detected in our study. Resistance was observed most commonly to tobramycin (66.2%), kanamycin (48.6%), and amikacin (29.7%) and less frequently to ciprofloxacin (4.1%), amoxicillin-clavulanic acid (5.4%), and ceftriaxone (9.5%) in isolates recovered from calves and goats fecal samples, whereas, all human isolates were sensitive to ceftazidime, ciprofloxacin, tobramycin and imipenem, respectively. Furthermore, Ag43 was detected in 60 STEC isolated from animals and 5 human origins (no eaeA gene was found in this study). Biofilm formation from Ag43[+] and Ag43[-] colonies showed 20 isolates with strong biofilm activities. Cefotaxime resistance phenotype was transferred to E. coli ATCC 25922.1 (Nal[r]) by conjugation at a frequency of 1.6×10[-4].

CONCLUSION: From the above results we concluded that, human infections with non-O157 STEC were significantly low in Kerman. Ag43 was insignificant with biofilm quantity in most cases.}, } @article {pmid29213262, year = {2017}, author = {Strempel, N and Nusser, M and Neidig, A and Brenner-Weiss, G and Overhage, J}, title = {The Oxidative Stress Agent Hypochlorite Stimulates c-di-GMP Synthesis and Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2311}, pmid = {29213262}, issn = {1664-302X}, abstract = {The opportunistic human pathogen Pseudomonas aeruginosa is able to survive under a variety of often harmful environmental conditions due to a multitude of intrinsic and adaptive resistance mechanisms, including biofilm formation as one important survival strategy. Here, we investigated the adaptation of P. aeruginosa PAO1 to hypochlorite (HClO), a phagocyte-derived host defense compound and frequently used disinfectant. In static biofilm assays, we observed a significant enhancement in initial cell attachment in the presence of sublethal HClO concentrations. Subsequent LC-MS analyses revealed a strong increase in cyclic-di-GMP (c-di-GMP) levels suggesting a key role of this second messenger in HClO-induced biofilm development. Using DNA microarrays, we identified a 26-fold upregulation of ORF PA3177 coding for a putative diguanylate cyclase (DGC), which catalyzes the synthesis of the second messenger c-di-GMP - an important regulator of bacterial motility, sessility and persistence. This DGC PA3177 was further characterized in more detail demonstrating its impact on P. aeruginosa motility and biofilm formation. In addition, cell culture assays attested a role for PA3177 in the response of P. aeruginosa to human phagocytes. Using a subset of different mutants, we were able to show that both Pel and Psl exopolysaccharides are effectors in the PA3177-dependent c-di-GMP network.}, } @article {pmid29213029, year = {2017}, author = {Liu, T and Chen, Y and Bi, G and Luo, J and Du, Z and Kong, J and Chen, Y}, title = {Generation of Methicillin-Resistant Staphylococcus Aureus Biofilm Infection in an Immunosuppressed Rat Model.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {23}, number = {}, pages = {5803-5811}, pmid = {29213029}, issn = {1643-3750}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Disease Models, Animal ; Immunocompromised Host/*drug effects ; Male ; Methicillin ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Rats/immunology ; Rats, Sprague-Dawley ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects ; }, abstract = {BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen responsible for many related infections, and immunosuppressed individuals are more susceptible. Its pathogenicity is associated with its virulence factors, resistance to antibiotics, and ability to form biofilm (BF). MRSA-BF infections in immunosuppressed patients pose great difficulties to clinical treatment. MATERIAL AND METHODS The study aimed to establish a model of MRSA-BF infection in rats with cyclophosphamide (CTX)-induced immunosuppression. For this, rats were administered CTX on days 1 and 4. White blood cells (WBC) were counted, then rats were inoculated with a clinical MRSA 17546 (t037) on day 5. Rats were sacrificed on days 6-10 and tissue samples were examined by scanning electron microscopy. RESULTS Using the dose of CTX: 150 (mg/kg) + 100 (mg/kg) is better than the other 2 programs as the survival rates of the immunocompromised rats were higher than in the other 2 immunosuppressive groups. The survival rate was not different between rats in the clean environment and in the SPF environment. However, the survival rate was affected by the sample acquisitions. Importantly, WBC counts started to decline on day 4, and then started to rise on day 9. Moreover, MRSA-BFs were formed earlier in immunosuppressed rats compared to the normal rats, as shown by scanning electron microscopy. CONCLUSIONS The study successfully established an immunosuppressed rat model of MRSA-BF infection, which provides methodological and data support for establishment of such animal models and is useful reference for related research. Our results may help further investigation of MRSA-BF infection.}, } @article {pmid29209869, year = {2017}, author = {Khelissa, SO and Jama, C and Abdallah, M and Boukherroub, R and Faille, C and Chihib, NE}, title = {Correction to: Effect of incubation duration, growth temperature, and abiotic surface type on cell surface properties, adhesion and pathogenicity of biofilm-detached Staphylococcus aureus cells.}, journal = {AMB Express}, volume = {7}, number = {1}, pages = {216}, pmid = {29209869}, issn = {2191-0855}, abstract = {Following publication of the original article (Khelissa et al. 2017), the authors reported that the legend for Fig. 3 contained an error. Instead of "Adhesion of planktonic and biofilm-detached Staphylococcus aureus cells on stainless steel and polycarbonate. Cell cultures were grown at 20, 30 and 37 °C, during 24 h (white square) and 48 h (white square). Planktonic cells adhesion on stainless steel (a) and polycarbonate (b). Adhesion of stainless steel-biofilm-detached-cells on stainless steel 24 (c) and polycarbonate-biofilm-detached-cells on polycarbonate (d)", the legend should read "Adhesion of planktonic and biofilm-detached Staphylococcus aureus cells on stainless steel and polycarbonate. Cell cultures were grown at 20, 30 and 37 °C, during 24 h (black square) and 48 h (white square). Planktonic cells adhesion on stainless steel (a) and polycarbonate (b). Adhesion of stainless steel-biofilm-detached-cells on stainless steel 24}, } @article {pmid29209305, year = {2017}, author = {Forestier, C and Billard, E and Milon, G and Gueirard, P}, title = {Unveiling and Characterizing Early Bilateral Interactions between Biofilm and the Mouse Innate Immune System.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2309}, pmid = {29209305}, issn = {1664-302X}, abstract = {A very substantial progress has been made in our understanding of infectious diseases caused by invasive bacteria. Under their planktonic forms, bacteria transiently reside in the otherwise sterile mammal body tissues, as the physiological inflammation insures both their clearance and repair of any tissue damage. Yet, the bacteria prone to experience planktonic to biofilm developmental transition still need to be studied. Of note, sessile bacteria not only persist but also concur preventing the effectors and regulators of the physiological inflammation to operate. Thus, it is urgent to design biologically sound experimental approaches aimed to extract, at the earliest stage, immune signatures of mono-bacteria planktonic to biofilm developmental transition in vivo and ex vivo. Indeed, the transition is often the first event to which succeeds the "chronicization" process whereby classical bacteria-targeting therapies are no more efficacious. An in vivo model of micro-injection of Staphylococcus aureus planktonic or biofilm cells in the ear pinna dermis of laboratory transgenic mice with fluorescent immune cells is proposed. It allows visualizing, in real time, the range of the early interactions between the S. aureus and myeloid cell subsets- the resident macrophages and dendritic cells, the recruited neutrophil granulocytes/polymorphonuclear neutrophils, monocytes otherwise known to differentiate as macrophages or dendritic cells. One main objective is to extract contrasting immune signatures of the modulation of the physiological inflammation with respect to the two bacterial lifestyles.}, } @article {pmid29209288, year = {2017}, author = {Sharafutdinov, IS and Trizna, EY and Baidamshina, DR and Ryzhikova, MN and Sibgatullina, RR and Khabibrakhmanova, AM and Latypova, LZ and Kurbangalieva, AR and Rozhina, EV and Klinger-Strobel, M and Fakhrullin, RF and Pletz, MW and Bogachev, MI and Kayumov, AR and Makarewicz, O}, title = {Antimicrobial Effects of Sulfonyl Derivative of 2(5H)-Furanone against Planktonic and Biofilm Associated Methicillin-Resistant and -Susceptible Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2246}, pmid = {29209288}, issn = {1664-302X}, abstract = {The gram-positive opportunistic bacterium Staphylococcus aureus is one of the most common causatives of a variety of diseases including skin and skin structure infection or nosocomial catheter-associated infections. The biofilm formation that is an important virulence factor of this microorganism renders the antibiotic therapy ineffective, because biofilm-embedded bacteria exhibit strongly increased tolerance to antimicrobials. Here, we describe a novel 3-chloro-5(S)-[(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-4-[4-methylphenylsulfonyl]-2(5H)-furanone (F105), possessing a sulfonyl group and l-menthol moiety. Minimal inhibitory and bactericidal concentration values (MIC and MBC) of F105 were 10 and 40 mg/L, respectively, suggesting F105 biocidal properties. F105 exhibits pronounced activity against biofilm-embedded S. aureus and increases the efficacy of aminoglycosides (amikacin, gentamicin, and kanamycin) and benzalkonium chloride with fractional inhibitory concentration index values of 0.33-0.44 and 0.29, respectively, suggesting an alternative external treatment option, e.g., for wound infections. Moreover, low concentrations (0.5-1.3 mg/L) of F105 reduced the MICs of these antimicrobials twofold. By using confocal laser scanning microscopy and CFU counting, we show explicitly that F105 also restores the antimicrobial activity of gentamicin and ampicillin against S. aureus biofilms by several orders of magnitude. Biofilm structures were not destroyed but sterilized, with embedded cells being almost completely killed at twofold MBC. While F105 is quite toxic (CC50/MBC ratio 0.2), our data suggest that the F105 chemotype might be a promising starting point for the development of complex topical agents for combined anti-staphylococcal biofilm-therapies restoring the efficacy of some antibiotics against difficult to treat S. aureus biofilm.}, } @article {pmid29208399, year = {2018}, author = {Yoo, A and Rossi-Fedele, G and Kidd, SP and Rogers, AH and Zilm, PS}, title = {Association between Extracellular Material and Biofilm Formation in Response to Sodium Hypochlorite by Clinical Isolates of Enterococcus faecalis.}, journal = {Journal of endodontics}, volume = {44}, number = {2}, pages = {269-273}, doi = {10.1016/j.joen.2017.08.025}, pmid = {29208399}, issn = {1878-3554}, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Enterococcus faecalis/*drug effects/genetics/metabolism ; Gelatinases/metabolism ; Membrane Proteins/genetics ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Polymerase Chain Reaction ; Sodium Hypochlorite/*pharmacology ; }, abstract = {INTRODUCTION: Extracellular material (ECM) surrounding Enterococcus faecalis may play a role in increasing resistance to environmental stresses. Our aim was to determine ECM levels in response to subminimal inhibitory concentrations of sodium hypochlorite (sub-MIC/NaOCl) or anaerobic growth and determine the impact on biofilm development.

METHODS: From 37 E. faecalis clinical strains, 19 were selected according to their biofilm-producing ability by using a crystal violet biofilm assay: 10 strong, 4 intermediate, and 5 non-biofilm producers. Biofilm assays were subsequently performed on all strains when subjected to sub-MIC/NaOCl. All strains were evaluated for ECM production under aerobic and anaerobic conditions and with sub-MIC/NaOCl. ECM production was assessed by using scanning electron microscopy. Double-blinded independent assessors were used to score levels of ECM production. The esp gene was detected by using polymerase chain reaction. Gelatinase activity was determined by using Todd-Hewitt and gelatin agar.

RESULTS: In aerobic conditions, ECM was expressed in all strains. In the presence of sub-MIC/NaOCl, of the 10 strong biofilm producers, 5 increased their ECM production, and 4 showed increased biofilm growth. Two strains had less ECM production and showed decreased biofilm growth. One isolate demonstrated no observable changes. Most non-biofilm producers demonstrated no observable differences in ECM production, although 1 strain increased biofilm growth. ECM production in anaerobic conditions was highly variable. The esp gene (n = 15) and gelatinase activity (n = 7) were evident among the isolates.

CONCLUSIONS: Clonal diversity among strains of E. faecalis suggests that some strong biofilm producers can upregulate ECM production and increase biofilm growth in response to sub-MIC/NaOCl.}, } @article {pmid29205189, year = {2017}, author = {Shukla, SK and Rao, TS}, title = {Staphylococcus aureus biofilm removal by targeting biofilm-associated extracellular proteins.}, journal = {The Indian journal of medical research}, volume = {146}, number = {Supplement}, pages = {S1-S8}, pmid = {29205189}, issn = {0971-5916}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage ; Bacterial Proteins/antagonists & inhibitors/*genetics ; Biofilms/*drug effects/growth & development ; Cattle ; Drug Resistance, Bacterial/drug effects/genetics ; Endopeptidase K/*administration & dosage/adverse effects ; Female ; Humans ; Mastitis, Bovine/*drug therapy/microbiology/pathology ; Staphylococcus aureus/*drug effects/genetics/pathogenicity ; }, abstract = {BACKGROUND & OBJECTIVES: Among cell surface proteins, biofilm-associated protein (Bap) promotes biofilm development in Staphylococcus aureus strains. The aim of this study was to investigate proteinase-mediated biofilm dispersion in different isolates of S. aureus.

METHODS: Biofilm assay was done in 96-well microtitre plate to evaluate the effect of proteinase K on biofilms of bovine mastitis S. Aureus isolates. Extracellular polymeric substances were extracted and evaluated for their composition (protein, polysaccharides and extracellular DNA), before and after the proteinase K treatment.

RESULTS: Biofilm assay showed that 2 μg/ml proteinase K significantly inhibited biofilm development in bap-positive S. aureus V329 as well as other S. aureus isolates (SA7, SA10, SA33, SA352), but not in bap-mutant M556 and SA392 (a weak biofilm-producing strain). Proteinase K treatment on S. aureus planktonic cells showed that there was no inhibition of planktonic growth up to 32 μg/ml of proteinase K. Proteinase K treatment on 24 h old preformed biofilms showed an enhanced dispersion of bap-positive V329 and SA7, SA10, SA33 and SA352 biofilms; however, proteinase K did not affect the bap-mutant S. aureus M556 and SA392 biofilms. Biofilm compositions study before and after proteinase K treatment indicated that Bap might also be involved in eDNA retention in the biofilm matrix that aids in biofilm stability. When proteinase K was used in combination with antibiotics, a synergistic effect in antibiotic efficacy was observed against all biofilm-forming S. aureus isolates.

Proteinase K inhibited biofilms growth in S. aureus bovine mastitis isolates but did not affect their planktonic growth. An enhanced dispersion of preformed S. aureus biofilms was observed on proteinase K treatment. Proteinase K treatment with antibiotics showed a synergistic effect against S. aureus biofilms. The study suggests that dispersing S. aureus by protease can be of use while devising strategies againstS. aureus biofilms.}, } @article {pmid29203111, year = {2018}, author = {Nguyen, MT and Luqman, A and Bitschar, K and Hertlein, T and Dick, J and Ohlsen, K and Bröker, B and Schittek, B and Götz, F}, title = {Staphylococcal (phospho)lipases promote biofilm formation and host cell invasion.}, journal = {International journal of medical microbiology : IJMM}, volume = {308}, number = {6}, pages = {653-663}, doi = {10.1016/j.ijmm.2017.11.013}, pmid = {29203111}, issn = {1618-0607}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Disease Models, Animal ; Hemolysis ; Host-Pathogen Interactions ; Mice ; Mutation ; Phospholipases/*genetics ; Skin/microbiology ; Staphylococcal Infections/blood ; Staphylococcus/*enzymology/genetics/*pathogenicity ; Triolein/pharmacology ; Virulence ; }, abstract = {Most Staphylococcus aureus strains secrete two lipases SAL1 and SAL2 encoded by gehA and gehB. These two lipases differ with respect to their substrate specificity. Staphylococcus hyicus secretes another lipase, SHL, which is in contrast to S. aureus lipases Ca[2+]-dependent and has a broad-spectrum lipase and phospholipase activity. The aim of this study was to investigate the role of staphylococcal (phospho) lipases in virulence. For this we constructed a gehA-gehB double deletion mutant in S. aureus USA300 and expressed SHL in agr-positive (accessory gene regulator) and agr-negative S. aureus strains. The lipases themselves have no hemolytic or cytotoxic activity. However, in agr-negative strains SHL-expression caused an upregulation of hemolytic activity. We further show that SHL-expression significantly enhanced biofilm formation probably due to an increase of extracellular DNA release. SHL-expression also increased host cell invasion 4-6-fold. Trioleate, a main triacylglycerol component of mammalian skin, induced lipase production. Finally, in the mouse sepsis and skin colonization models the lipase producing and mutant strain showed no significant difference compared to the WT strain. In conclusion, we show that staphylococcal lipases promote biofilm formation and host cell invasion and thereby contribute to S. aureus virulence.}, } @article {pmid29202722, year = {2017}, author = {Pérez-Granda, MJ and Latorre, MC and Alonso, B and Hortal, J and Samaniego, R and Bouza, E and Guembe, M}, title = {Eradication of P. aeruginosa biofilm in endotracheal tubes based on lock therapy: results from an in vitro study.}, journal = {BMC infectious diseases}, volume = {17}, number = {1}, pages = {746}, pmid = {29202722}, issn = {1471-2334}, support = {CP13/00268//Instituto de Salud Carlos III/International ; PEJ15/BIO/AI-0406//Consejería de Educación, Juventud y Deporte, Comunidad de Madrid/International ; }, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/drug effects ; Dose-Response Relationship, Drug ; Humans ; Intubation, Intratracheal/*instrumentation ; Pneumonia, Ventilator-Associated/microbiology ; Pseudomonas aeruginosa/*drug effects/pathogenicity/physiology ; }, abstract = {BACKGROUND: Despite the several strategies available for the management of biofilm-associated ventilator-associated pneumonia, data regarding the efficacy of applying antibiotics to the subglottic space (SS) are scarce. We created an in vitro model to assess the efficacy of antibiotic lock therapy (ALT) applied in the SS for eradication of Pseudomonas aeruginosa biofilm in endotracheal tubes (ETTs).

METHODS: We applied 2 h of ALT to a P. aeruginosa biofilm in ETTs using a single dose (SD) and a 5-day therapy model (5D). We used sterile saline lock therapy (SLT) as the positive control. We compared colony count and the percentage of live cells between both models.

RESULTS: The median (IQR) cfu counts/ml and percentage of live cells in the SD-ALT and SD-SLT groups were, respectively, 3.12 × 10[5] (9.7 × 10[4]-0) vs. 8.16 × 10[7] (7.0 × 10[7]-0) (p = 0.05) and 53.2% (50.9%-57.2%) vs. 91.5% (87.3%-93.9%) (p < 0.001). The median (IQR) cfu counts/ml and percentage of live cells in the 5D-ALT and 5D-SLT groups were, respectively, 0 (0-0) vs. 3.2 × 10[7] (2.32 × 10[7]-0) (p = 0.03) and 40.6% (36.6%-60.0%) vs. 90.3% (84.8%-93.9%) (p < 0.001).

CONCLUSION: We demonstrated a statistically significant decrease in the viability of P. aeruginosa biofilm after application of 5D-ALT in the SS. Future clinical studies to assess ALT in patients under mechanical ventilation are needed.}, } @article {pmid29201204, year = {2017}, author = {Zhang, X and Ma, YF and Wang, L and Jiang, N and Qin, CH and Hu, YJ and Yu, B}, title = {A rabbit model of implant-related osteomyelitis inoculated with biofilm after open femoral fracture.}, journal = {Experimental and therapeutic medicine}, volume = {14}, number = {5}, pages = {4995-5001}, pmid = {29201204}, issn = {1792-0981}, abstract = {Currently, animal models used in research on implant-associated osteomyelitis primarily use intramedullary fixation and initial inoculum of planktonic bacterial cells. However, these techniques have certain limitations, including lack of rotational stability and instable inoculation. To improve these models, the present study aimed to establish a novel rabbit model of implant-associated osteomyelitis using biofilm as the initial inoculum following plate fixation of the femoral fracture. A total of 24 New Zealand White rabbits were randomly divided into two equal groups. Osteotomy was performed at the right femoral shaft using a wire saw following fixation with a 5-hole stainless steel plate. The plates were not colonized with bacteria in group 1, but colonized with a biofilm of Staphylococcus aureus (American Type Culture Collection, 25923) in group 2. All the rabbits were sacrificed after 21 days for clinical, X-ray, micro-computed tomography and histological assessments of the severity of osteomyelitis. Scanning electron microscopy and confocal laser scanning microscopy were used for biofilm assessment. In group 2, pus formation, periosteal reaction, cortical destruction and absorption were observed in all the rabbits and biofilm formation was observed on all the plates. However, no pus formation was observed except for a slight inflammatory response and all the plates appeared clean without infection in group 1. The differences between the two groups were statistically significant regarding histologic scores and semi-quantification of the bacteria on the plates (P<0.001). In the present study, a novel rabbit model of infection following internal plate fixation of open fracture was successfully established, providing a novel tool for the study of implant-associated osteomyelitis.}, } @article {pmid29199458, year = {2018}, author = {Pandit, S and Jung, JE and Choi, HM and Jeon, JG}, title = {Effect of brief periodic fluoride treatments on the virulence and composition of a cariogenic biofilm.}, journal = {Biofouling}, volume = {34}, number = {1}, pages = {53-61}, doi = {10.1080/08927014.2017.1404583}, pmid = {29199458}, issn = {1029-2454}, mesh = {Biofilms/*drug effects ; Cariostatic Agents/*pharmacology ; Dental Caries/*microbiology ; Dose-Response Relationship, Drug ; Fluorides/*pharmacology ; Gene Expression/drug effects ; Genes, Bacterial ; Humans ; Microbial Viability/drug effects/genetics ; Models, Biological ; Oral Hygiene/*methods ; Streptococcus mutans/*drug effects/genetics/physiology ; Virulence/drug effects/genetics ; }, abstract = {The present study investigated the effect of periodic 1-min fluoride treatments on Streptococcus mutans biofilms and then determined the relationship between anti-biofilm activity, treatment frequency, and fluoride concentration using a linear-fitting procedure. S. mutans biofilms were periodically treated (1-min/treatment) with fluoride during biofilm formation and analyzed using microbiological methods, confocal microscopy, and real-time PCR. The results indicated that reductions in the dry weight and acidogenicity of biofilms due to periodic fluoride treatment occurred in a concentration dependent manner. The reduction in dry weight without affecting bacterial cell viability was observed mainly due to the inhibitory effect of fluoride on gtfB and gtfC gene expression, which suppresses EPS production and avoids reduction of the pH below the critical point on the tooth surface. This study suggests that brief periodic exposure to appropriate fluoride concentrations through mouthwashes and toothpastes may affect the virulence and composition of cariogenic biofilms and subsequently prevent dental caries.}, } @article {pmid29198862, year = {2018}, author = {Sall, C and Ayé, M and Bottzeck, O and Praud, A and Blache, Y}, title = {Towards smart biocide-free anti-biofilm strategies: Click-based synthesis of cinnamide analogues as anti-biofilm compounds against marine bacteria.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {28}, number = {2}, pages = {155-159}, doi = {10.1016/j.bmcl.2017.11.039}, pmid = {29198862}, issn = {1464-3405}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Coumaric Acids/chemical synthesis/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Paracoccus/*drug effects/growth & development ; Pseudoalteromonas/*drug effects/growth & development ; Structure-Activity Relationship ; }, abstract = {A set of triazole-based analogues of N-coumaroyltyramine was designed to discover potential leads that may help in the control of bacterial biofilms. the most potent compounds act as inhibitors of biofilm development with EC50 closed to ampicillin (EC50 = 11 μM) without toxic effect on bacterial growth even at high concentrations(100 μM).}, } @article {pmid29197425, year = {2017}, author = {Nawar, A and Khoja, AH and Akbar, N and Ansari, AA and Qayyum, M and Ali, E}, title = {Physical abrasion method using submerged spike balls to remove algal biofilm from photobioreactors.}, journal = {BMC research notes}, volume = {10}, number = {1}, pages = {666}, pmid = {29197425}, issn = {1756-0500}, mesh = {*Biofilms ; *Chlorella vulgaris ; *Microalgae ; *Photobioreactors ; }, abstract = {OBJECTIVE: A major factor in practical application of photobioreactors (PBR) is the adhesion of algal cells onto their inner walls. Optimized algal growth requires an adequate sunlight for the photosynthesis and cell growth. Limitation in light exposure adversely affects the algal biomass yield. The removal of the biofilm from PBR is a challenging and expansive task. This study was designed to develop an inexpensive technique to prevent adhesion of algal biofilm on tubular PBR to ensure high efficiency of light utilization. Rubber balls with surface projections were introduced into the reactor, to remove the adherent biofilm by physical abrasion technique.

RESULTS: The floatation of spike balls created a turbulent flow, thereby inhibiting further biofilm formation. The parameters such as, specific growth rate and doubling time of the algae before introducing the balls were 0.451 day[-1] and 1.5 days respectively. Visible biofilm impeding light transmission was formed by 15-20 days. The removal of the biofilm commenced immediately after the introduction of the spike balls with visibly reduced deposits in 3 days. This was also validated by enhance cell count (6.95 × 106 cells mL[-1]) in the medium. The employment of spike balls in PBR is an environmental friendly and economical method for the removal of biofilm.}, } @article {pmid29197139, year = {2018}, author = {El-Wassefy, NA and El-Mahdy, RH and El-Kholany, NR}, title = {The impact of silver nanoparticles integration on biofilm formation and mechanical properties of glass ionomer cement.}, journal = {Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.]}, volume = {30}, number = {2}, pages = {146-152}, doi = {10.1111/jerd.12353}, pmid = {29197139}, issn = {1708-8240}, mesh = {Biofilms ; Glass Ionomer Cements ; Humans ; Materials Testing ; *Metal Nanoparticles ; *Silver ; Staphylococcus aureus ; }, abstract = {OBJECTIVES: To study the effect of silver nanoparticles incorporation to glass ionomer cement (GIC) on the Staphylococcus aureus biofilm in terms of bacterial growth and evaluate the incorporating effect on hardness and compressive strength.

METHODS: Silver nanopowder was added in concentration 0, 1, 3, and 5 wt% to the conventional powder of GIC Fuji IX GP and then the powder is added to the liquid and mixed together with the recommended Powder/liquid ratio of 3.6:1 g. One hundred and twenty disc and cylindrical-shaped specimens were prepared using teflon molds. The specimens were put in tissue culture plate wells contained S. aureus in brain-heart infusion broth. The plate was incubated at 37°C for 24 h. Specimens were then washed, fixed, dehydrated, and air dried. The spatial distribution of biofilm was examined via scanning electron microscope. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also evaluated. After setting, the specimens were stored in distilled water for 24 h before testing for microhardness and compressive strength.

RESULTS: Scanning electron photomicrographs of biofilm formed on the control GIC, showed a consistent biofilm with a thick sheet of cells, whereas those formed were less dense at 3 wt% and below the detection limit at 5 wt% silver nanoparticles. MIC and MBC of S. aureus were 25 and 50 µg/mL, respectively. The microhardness and compressive strength values of tested groups showed a nonsignificant decrease from the control group, P = .58 and .82, respectively.

CONCLUSION: Incorporation of silver nanoparticles with GIC can limit S. aureus biofilm formation with an insignificant effect on mechanical properties and noticeable influence on its coloration, which restrict its usage in areas where esthetic is not of major concern.

CLINICAL SIGNIFICANCE: As the modification of GIC with silver nanoparticles improved the antibiofilm properties without altering its mechanical properties, it could be used as a restoration of root carious lesion mainly in nonesthetic areas, a base under composite restorations in deep posterior cavities and as a core material in caries susceptible patients.}, } @article {pmid29196655, year = {2017}, author = {Amores, GR and de Las Heras, A and Sanches-Medeiros, A and Elfick, A and Silva-Rocha, R}, title = {Systematic identification of novel regulatory interactions controlling biofilm formation in the bacterium Escherichia coli.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {16768}, pmid = {29196655}, issn = {2045-2322}, mesh = {*Biofilms ; Escherichia coli/*physiology ; Escherichia coli Proteins/*genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Phenotype ; Plankton/microbiology ; Promoter Regions, Genetic ; Protein Binding ; Transcription, Genetic ; }, abstract = {Here, we investigated novel interactions of three global regulators of the network that controls biofilm formation in the model bacterium Escherichia coli using computational network analysis, an in vivo reporter assay and physiological validation experiments. We were able to map critical nodes that govern planktonic to biofilm transition and identify 8 new regulatory interactions for CRP, IHF or Fis responsible for the control of the promoters of rpoS, rpoE, flhD, fliA, csgD and yeaJ. Additionally, an in vivo promoter reporter assay and motility analysis revealed a key role for IHF as a repressor of cell motility through the control of FliA sigma factor expression. This investigation of first stage and mature biofilm formation indicates that biofilm structure is strongly affected by IHF and Fis, while CRP seems to provide a fine-tuning mechanism. Taken together, the analysis presented here shows the utility of combining computational and experimental approaches to generate a deeper understanding of the biofilm formation process in bacteria.}, } @article {pmid29196246, year = {2018}, author = {Pérez-Laguna, V and García-Luque, I and Ballesta, S and Pérez-Artiaga, L and Lampaya-Pérez, V and Samper, S and Soria-Lozano, P and Rezusta, A and Gilaberte, Y}, title = {Antimicrobial photodynamic activity of Rose Bengal, alone or in combination with Gentamicin, against planktonic and biofilm Staphylococcus aureus.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {21}, number = {}, pages = {211-216}, doi = {10.1016/j.pdpdt.2017.11.012}, pmid = {29196246}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/drug effects ; Drug Therapy, Combination ; Gentamicins/*pharmacology ; Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Plankton/drug effects ; Rose Bengal/administration & dosage/*pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {Antimicrobial photodynamic therapy (aPDT) could constitute an alternative therapy to antibiotics especially against superficial infections caused by bacteria involved in multidrug resistance processes. The aim of this study is to compare the efficacy of aPDT using the photosensitizer rose bengal (RB), combined or uncombined with gentamicin (GN), against Staphylococcus aureus. Different concentrations of RB (ranging from 0.03 to 64 μg/ml) were added to S. aureus in water suspensions or forming biofilms in the absence or presence of GN (1-40 μg/ml) and the samples were irradiated (18 or 37 J/cm[2]). The number of viable bacteria was quantified by counting colony-forming units. RB-aPDT shows significant photoactivity. The combination of GN and RB-aPDT exerts a synergistic bactericidal effect against planktonic S. aureus. On the other hand, a synergistic effect is observed only when the maximum concentration tested of RB and GN was used in biofilm. According to these result the use of RB-aPDT alone or in combination with GN could be implemented against S. aureus.}, } @article {pmid29196015, year = {2017}, author = {Deng, Q and Pu, Y and Sun, L and Wang, Y and Liu, Y and Wang, R and Liao, J and Xu, D and Liu, Y and Ye, R and Fang, Z and Gooneratne, R}, title = {Antimicrobial peptide AMPNT-6 from Bacillus subtilis inhibits biofilm formation by Shewanella putrefaciens and disrupts its preformed biofilms on both abiotic and shrimp shell surfaces.}, journal = {Food research international (Ottawa, Ont.)}, volume = {102}, number = {}, pages = {8-13}, doi = {10.1016/j.foodres.2017.09.057}, pmid = {29196015}, issn = {1873-7145}, mesh = {Animal Shells/*microbiology ; Animals ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Bacillus subtilis/*chemistry ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Food Microbiology/*methods ; Food Preservation/methods ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Penaeidae/*microbiology ; Polystyrenes/chemistry ; Seafood/*microbiology ; Shewanella putrefaciens/*drug effects/growth & development/ultrastructure ; Stainless Steel/chemistry ; Surface Properties ; Time Factors ; }, abstract = {Shewanella putrefaciens biofilm formation is of great concern for the shrimp industry because it adheres easily to food and food-contact surfaces and is a source of persistent and unseen contamination that causes shrimp spoilage and economic losses to the shrimp industry. Different concentrations of an antimicrobial lipopeptide, the fermentation product of Bacillus subtilis, AMPNT-6, were tested for the ability to reduce adhesion and disrupt S. putrefaciens preformed biofilms on two different contact surfaces (shrimp shell, stainless steel sheet). AMPNT-6 displayed a marked dose- and time-dependent anti-adhesive effect>biofilm removal. 3MIC AMPNT-6 was able both to remove biofilm and prevent bacteria from forming biofilm in a 96-well polystyrene microplate used as the model surface. 2MIC AMPNT-6 prevented bacteria from adhering to the microplate surface to form biofilm for 3h and removed already existing biofilm within 24h. Secretion of extracellular polymeric substances incubated in LB broth for 24h by S. putrefaciens was minimal at 3× MIC AMPNT-6. Scanning electron microscopy showed that damage to S. putrefaciens bacteria by AMPNT-6 possibly contributed to the non-adherence to the surfaces. Disruption of the mature biofilm structure by AMPNT-6 contributed to biofilm removal. It is concluded that AMPNT-6 can be used effectively to prevent attachment and also detach S. putrefaciens biofilms from shrimp shells, stainless steel sheets and polystyrene surfaces.}, } @article {pmid29195980, year = {2017}, author = {Meireles, A and Ferreira, C and Melo, L and Simões, M}, title = {Comparative stability and efficacy of selected chlorine-based biocides against Escherichia coli in planktonic and biofilm states.}, journal = {Food research international (Ottawa, Ont.)}, volume = {102}, number = {}, pages = {511-518}, doi = {10.1016/j.foodres.2017.09.033}, pmid = {29195980}, issn = {1873-7145}, mesh = {Biofilms/*drug effects/growth & development ; Chlorine Compounds/chemistry/*pharmacology ; Disinfectants/chemistry/*pharmacology ; Equipment Contamination/*prevention & control ; Escherichia coli/*drug effects/growth & development/metabolism ; Industrial Microbiology/*methods ; Microbial Viability/drug effects ; Oxides/chemistry/*pharmacology ; Reactive Oxygen Species/metabolism ; Sodium Hypochlorite/chemistry/*pharmacology ; Time Factors ; Triazines/chemistry/*pharmacology ; *Water/chemistry ; }, abstract = {Microbial contamination is an unavoidable problem in industrial processes. Sodium hypochlorite (SH) is the most common biocide used for industrial disinfection. However, in view of the current societal concerns on environmental and public health aspects, there is a trend to reduce the use of this biocide as it can lead to the formation of organochlorinated carcinogenic compounds. In this work the efficacy of SH was assessed against Escherichia coli in planktonic and biofilm states and compared with three alternative chlorine-based biocides: neutral electrolyzed oxidizing water (NEOW), chlorine dioxide (CD) and sodium dichloroisocyanurate (NaDCC). The planktonic tests revealed that SH had the fastest antimicrobial action, NaDCC exhibited the highest antimicrobial rate and NEOW caused the highest antimicrobial effects. Additionally, NEOW was the biocide that allowed the highest formation of reactive oxygen species (ROS). In biofilm control, NEOW and CD were the most efficient biocides causing 3.26 and 3.20 log CFU·cm[-2] reduction, respectively. In terms of stability for chlorine depletion, NEOW had the longest decay time for chlorine loss (70days at 5°C) and the lowest chlorine loss rate (0.013ppm·min[-1] at 5°C). CD and NaDCC had equivalent stability. The overall results demonstrated NEOW as a good alternative to SH due to its higher antimicrobial effects and lower chlorine depletion over time.}, } @article {pmid29195151, year = {2018}, author = {Zheng, Y and Zhang, W and Tang, B and Ding, J and Zheng, Y and Zhang, Z}, title = {Membrane fouling mechanism of biofilm-membrane bioreactor (BF-MBR): Pore blocking model and membrane cleaning.}, journal = {Bioresource technology}, volume = {250}, number = {}, pages = {398-405}, doi = {10.1016/j.biortech.2017.11.036}, pmid = {29195151}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Membranes, Artificial ; Sewage ; Wastewater ; }, abstract = {Biofilm membrane bioreactor (BF-MBR) is considered as an important wastewater treatment technology that incorporates advantages of both biofilm and MBR process, as well as can alleviate membrane fouling, with respect to the conventional activated sludge MBR. But, to be efficient, it necessitates the establishment of proper methods for the assessment of membrane fouling. Four Hermia membrane blocking models were adopted to quantify and evaluate the membrane fouling of BF-MBR. The experiments were conducted with various operational conditions, including membrane types, agitation speeds and transmembrane pressure (TMP). Good agreement between cake formation model and experimental data was found, confirming the validity of the Hermia models for assessing the membrane fouling of BF-MBR and that cake layer deposits on membrane. Moreover, the influences of membrane types, agitation speeds and transmembrane pressure on the Hermia pore blocking coefficient of cake layer were investigated. In addition, the permeability recovery after membrane cleaning at various operational conditions was studied. This work confirms that, unlike conventional activated sludge MBR, BF-MBR possesses a low degree of membrane fouling and a higher membrane permeability recovery after cleaning.}, } @article {pmid29194975, year = {2018}, author = {Habimana, O and Casey, E}, title = {Biofilm recruitment under nanofiltration conditions: the influence of resident biofilm structural parameters on planktonic cell invasion.}, journal = {Microbial biotechnology}, volume = {11}, number = {1}, pages = {264-267}, pmid = {29194975}, issn = {1751-7915}, mesh = {Biofilms/*growth & development ; *Biofouling ; Filtration/*methods ; *Microbial Interactions ; Models, Theoretical ; Nanotechnology ; Pseudomonas fluorescens/*physiology ; Pseudomonas putida/*physiology ; Water Purification/*methods ; }, abstract = {It is now generally accepted that biofouling is inevitable in pressure-driven membrane processes for water purification. A large number of published articles describe the development of novel membranes in an effort to address biofouling in such systems. It is reasonable to assume that such membranes, even those with antimicrobial properties, when applied in industrial-scale systems will experience some degree of biofouling. In such a scenario, an understanding of the fate of planktonic cells, such as those entering with the feed water, has important implications with respect to contact killing particularly for membranes with antimicrobial properties. This study thus sought to investigate the fate of planktonic cells in a model nanofiltration biofouling system. Here, the interaction between auto-fluorescent Pseudomonas putida planktonic cells and 7-day-old Pseudomonas fluorescens resident biofilms was studied under permeate flux conditions in a nanofiltration cross flow system. We demonstrate that biofilm cell recruitment during nanofiltration is affected by distinctive biofilm structural parameters such as biofilm depth.}, } @article {pmid29194797, year = {2018}, author = {Akcalı, A and Lang, NP}, title = {Dental calculus: the calcified biofilm and its role in disease development.}, journal = {Periodontology 2000}, volume = {76}, number = {1}, pages = {109-115}, doi = {10.1111/prd.12151}, pmid = {29194797}, issn = {1600-0757}, mesh = {Animals ; Bacteria/metabolism ; Biofilms/*growth & development ; Biological Evolution ; Calcification, Physiologic ; Dental Calculus/*metabolism/*microbiology ; *Disease Progression ; Gingiva ; Humans ; Microbiota ; Mouth/microbiology ; Viruses ; }, abstract = {Dental calculus represents the first fossilized record of bacterial communities as a testimony of evolutionary biology. The development of dental calculus is a dynamic process that starts with a nonmineralized biofilm which eventually calcifies. Nonmineralized dental biofilm entraps particles from the oral cavity, including large amounts of oral bacteria, human proteins, viruses and food remnants, and preserves their DNA. The process of mineralization involves metabolic activities of the bacterial colonies and strengthens the attachment of nonmineralized biofilms to the tooth surface. From a clinical point of view, dental calculus always harbors a living, nonmineralized biofilm, jeopardizing the integrity of the dento-gingival or implanto-mucosal unit. This narrative review presents a brief historical overview of dental calculus formation and its clinical relevance in modern periodontal practice.}, } @article {pmid29194382, year = {2017}, author = {Rodrigues, CF and Henriques, M}, title = {Liposomal and Deoxycholate Amphotericin B Formulations: Effectiveness against Biofilm Infections of Candida spp.}, journal = {Pathogens (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {29194382}, issn = {2076-0817}, abstract = {BACKGROUND: candidiasis is the primary fungal infection encountered in patients undergoing prolonged hospitalization, and the fourth leading cause of nosocomial bloodstream infections. One of the most important Candida spp. virulence factors is the ability to form biofilms, which are extremely refractory to antimicrobial therapy and very difficult to treat with the traditional antifungal therapies. It is known that the prophylaxis or treatment of a systemic candidiasis are recurrently taken without considering the possibility of a Candida spp. biofilm-related infections. Therefore, it is important to assess the effectiveness of the available drugs and which formulations have the best performance in these specific infections.

METHODS: 24-h-biofilms of four Candida spp. and their response to two amphotericin B (AmB) pharmaceutical formulations (liposomal and deoxycholate) were evaluated.

RESULTS: generally, Candida glabrata was the less susceptible yeast species to both AmBs. MBECs revealed that it is therapeutically more appealing to use AmB-L than AmB-Deox for all Candida spp. biofilms, since none of the determined concentrations of AmB-L reached 10% of the maximum daily dose, but both formulations showed a very good capacity in the biomass reduction.

CONCLUSIONS: the liposomal formulation presents better performance in the eradication of the biofilm cells for all the species in comparison with the deoxycholate formulation.}, } @article {pmid29194257, year = {2018}, author = {Kim, SH and Park, CY and Hwang, SW and Chang, M}, title = {Clinical Significance of Biofilm on Silicone Tubes Removed From Patients With Nasolacrimal Duct Stenosis.}, journal = {The Journal of craniofacial surgery}, volume = {29}, number = {2}, pages = {462-465}, doi = {10.1097/SCS.0000000000004191}, pmid = {29194257}, issn = {1536-3732}, mesh = {*Biofilms ; Dacryocystorhinostomy ; Humans ; *Lacrimal Apparatus Diseases/etiology/microbiology/surgery ; Nasolacrimal Duct/*microbiology ; Prostheses and Implants/*microbiology ; Pseudomonas Infections ; Pseudomonas aeruginosa ; Silicones ; Staphylococcal Infections ; Staphylococcus aureus ; }, abstract = {PURPOSE: To determine the relationship between the optical density of biofilms on silicone tubes and surgical outcomes.

METHODS: A total of 43 silicone tubes from 33 patients with nasolacrimal duct stenosis were enrolled at 6 months after bicanalicular silicone tube intubation. The removed silicone tubes were divided into 2 segments. One segment of silicone tube was cultured while the other segment was used to measure optical density of biofilm. Each segment was divided into 3 pieces according to average normal human nasolacrimal anatomy. The first piece was located from puncta to lacrimal sac. The second piece was inside the nasolacrimal duct. The third piece was in the nasal cavity. Surgical outcome was evaluated at postoperative 12 months based on Munk score and fluorescein dye disappearance test.

RESULTS: A total of 31 (72.1%) patients were surgically successful while 12 (27.9%) patients had surgical failure with persistent epiphora. In the second piece of silicone tube, the mean optical density of biofilm was 0.2654 nm in the surgical success group and 0.4472 nm in the surgical failure group. These results showed statistically significant (P < 0.01) difference. The most frequently isolated organism was Staphylococcus aureus in the surgical success group (7 of 31 patients, 22.6%). It was Pseudomonas aeruginosa in the surgical failure group (6 of 12 patients, 50%).

CONCLUSION: This is the first study that determines the relationship between biofilm on silicone tube and surgical outcome. Biofilm formed on silicone tubes in nasolacrimal duct might cause surgical failure.}, } @article {pmid29193551, year = {2018}, author = {de Beer, DM and Botes, M and Cloete, TE}, title = {The microbial community of a biofilm contact reactor for the treatment of winery wastewater.}, journal = {Journal of applied microbiology}, volume = {124}, number = {2}, pages = {598-610}, doi = {10.1111/jam.13654}, pmid = {29193551}, issn = {1365-2672}, mesh = {Bacteria/classification/genetics/isolation & purification/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Bioreactors/microbiology ; Carbon/metabolism ; In Situ Hybridization, Fluorescence ; Industrial Waste/*analysis ; Nitrification ; Oxygen/metabolism ; Waste Disposal, Fluid/methods ; Wastewater/*microbiology ; }, abstract = {AIMS: To utilize a three-tiered approach to provide insight into the microbial community structure, the spatial distribution and the metabolic capabilities of organisms of a biofilm in the two towers of a high-rate biological contact reactor treating winery wastewater.

METHODS AND RESULTS: Next-generation sequencing indicated that bacteria primarily responsible for the removal of carbohydrates, sugars and alcohol were more abundant in tower 1 than tower 2 while nitrifying and denitrifying bacteria were more abundant in tower 2. Yeast populations differed in each tower. Fluorescent in situ hybridization coupled with confocal microscopy showed distribution of organisms confirming an oxygen gradient across the biofilm depth. The Biolog system (ECO plates) specified the different carbon-metabolizing profiles of the two biofilms.

CONCLUSIONS: The three-tiered approach confirmed that the addition of a second subunit to the bioreactor, expanded the treatment capacity by augmenting the microbial and metabolic diversity of the system, improving the treatment scope of the system.

A three-tiered biofilm analysis provided data required to optimize the design of a bioreactor to provide favourable conditions for the development of a microbial consortium, which has optimal waste removal properties for the treatment requirements at hand.}, } @article {pmid29191005, year = {2018}, author = {Wang, B and Liu, H and Sun, L and Jin, Y and Ding, X and Li, L and Ji, J and Chen, H}, title = {Construction of High Drug Loading and Enzymatic Degradable Multilayer Films for Self-Defense Drug Release and Long-Term Biofilm Inhibition.}, journal = {Biomacromolecules}, volume = {19}, number = {1}, pages = {85-93}, doi = {10.1021/acs.biomac.7b01268}, pmid = {29191005}, issn = {1526-4602}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/*pharmacology ; Bentonite/administration & dosage/chemistry ; Biofilms/*drug effects ; *Drug Delivery Systems ; Enzymes/*metabolism ; Escherichia coli/drug effects ; Gentamicins/administration & dosage/chemistry ; Hyaluronic Acid/administration & dosage/chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Rabbits ; Staphylococcus aureus/drug effects ; }, abstract = {Bacterial infections and biofilm formation on the surface of implants are important issues that greatly affect biomedical applications and even cause device failure. Construction of high drug loading systems on the surface and control of drug release on-demand is an efficient way to lower the development of resistant bacteria and biofilm formation. In the present study, (montmorillonite/hyaluronic acid-gentamicin)10 ((MMT/HA-GS)10) organic/inorganic hybrid multilayer films were alternately self-assembled on substrates. The loading dosage of GS was as high as 0.85 mg/cm[2], which could be due the high specific surface area of MMT. The obtained multilayer film with high roughness gradually degraded in hyaluronidase (HAS) solutions or a bacterial infection microenvironment, which caused the responsive release of GS. The release of GS showed dual enzyme and bacterial infection responsiveness, which also indicated good drug retention and on-demand self-defense release properties of the multilayer films. Moreover, the GS release responsiveness to E. coli showed higher sensitivity than that to S. aureus. There was only ∼5 wt % GS release from the film in PBS after 48 h of immersion, and the amount quickly increased to 30 wt % in 10[5] CFU/mL of E. coli. Importantly, the high drug dosage, smart drug release, and film peeling from the surface contributed to the efficient antibacterial properties and long-term biofilm inhibition functions. Both in vitro and in vivo antibacterial tests indicated efficient sterilization function and good mammalian cell and tissue compatibility.}, } @article {pmid29189900, year = {2018}, author = {Wang, J and Nong, XH and Amin, M and Qi, SH}, title = {Hygrocin C from marine-derived Streptomyces sp. SCSGAA 0027 inhibits biofilm formation in Bacillus amyloliquefaciens SCSGAB0082 isolated from South China Sea gorgonian.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {3}, pages = {1417-1427}, pmid = {29189900}, issn = {1432-0614}, support = {XDA100304002//Strategic Leading Special Science and Technology Program of Chinese Academy of Sciences/ ; 81673326//National Natural Science Foundation of China/ ; }, mesh = {Animals ; Anthozoa/*microbiology ; Bacillus amyloliquefaciens/*drug effects/growth & development ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; China ; Gene Expression Profiling ; Lactams, Macrocyclic/isolation & purification/*pharmacology ; Lipopeptides/metabolism ; Microbial Sensitivity Tests ; Staphylococcus aureus/drug effects/growth & development ; Streptomyces/*chemistry ; }, abstract = {Several ansamycins have been reported to inhibit bacterial biofilm formation and accelerate the eradication of developed biofilms, but little is known about the effect of hygrocin C, an ansamycin, on bacterial biofilm formation. Here, hygrocin C was isolated from the marine-derived Streptomyces sp. SCSGAA 0027 and reported for the first time to be capable of inhibiting the biofilm formation of Staphylococcus aureus and Bacillus amyloliquefaciens SCSGAB0082 with the production of anti-microbial lipopeptides from South China Sea gorgonian Subergorgia suberosa at concentrations of less than minimum inhibitory concentrations. Moreover, hygrocin C also promoted the eradication of developed biofilms, affected the biofilm architecture, and lowered the extracellular polymeric matrix formation, cell motility, and surface hydrophobicity in B. amyloliquefaciens, which was in accordance with the inhibition of biofilm formation. Furthermore, transcriptome analysis revealed that hygrocin C altered the transcripts of several genes associated with bacterial chemotaxis and flagellar, two-component system and the synthesis of arginine and histidine, which are important for bacterial biofilm formation. In conclusion, hygrocin C could be used as a potential biofilm inhibitor against S. aureus and B. amyloliquefaciens. But further genetic investigations are needed to provide more details for elucidation of the molecular mechanisms responsible for the effects of hygrocin C on B. amyloliquefaciens biofilm formation.}, } @article {pmid29188848, year = {2017}, author = {Xu, Q and Li, X and Jin, Y and Sun, L and Ding, X and Liang, L and Wang, L and Nan, K and Ji, J and Chen, H and Wang, B}, title = {Bacterial self-defense antibiotics release from organic-inorganic hybrid multilayer films for long-term anti-adhesion and biofilm inhibition properties.}, journal = {Nanoscale}, volume = {9}, number = {48}, pages = {19245-19254}, doi = {10.1039/c7nr07106j}, pmid = {29188848}, issn = {2040-3372}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Bentonite ; Biofilms/*drug effects ; Chymotrypsin ; Escherichia coli/drug effects ; Gentamicins ; Polylysine ; Staphylococcus aureus/drug effects ; Staphylococcus epidermidis/drug effects ; Surface Properties ; }, abstract = {Implant-associated bacterial infections pose serious medical and financial issues due to the colonization and proliferation of pathogens on the surface of the implant. The as-prepared traditional antibacterial surfaces can neither resist bacterial adhesion nor inhibit the development of biofilm over the long term. Herein, novel (montmorillonite/poly-l-lysine-gentamicin sulfate)8 ((MMT/PLL-GS)8) organic-inorganic hybrid multilayer films were developed to combine enzymatic degradation PLL for on-demand self-defense antibiotics release. Small molecule GS was loaded into the multilayer films during self-assembly and the multilayer films showed pH-dependent and linear growth behavior. The chymotrypsin- (CMS) and bacterial infections-responsive film degradation led to the peeling of the films and GS release. Enzyme-responsive GS release exhibited CMS concentration dependence as measured by the size of the inhibition zone and SEM images. Notably, the obtained antibacterial films showed highly efficient bactericidal activity which killed more than 99.9% of S. aureus in 12 h. Even after 3 d of incubation in S. aureus, E. coli or S. epidermidis solutions, the multilayer films exhibited inhibition zones of more than 1.5 mm in size. Both in vitro and in vivo antibacterial tests indicated good cell compatibility, and anti-inflammatory, and long-term bacterial anti-adhesion and biofilm inhibition properties.}, } @article {pmid29187848, year = {2017}, author = {Ming, D and Wang, D and Cao, F and Xiang, H and Mu, D and Cao, J and Li, B and Zhong, L and Dong, X and Zhong, X and Wang, L and Wang, T}, title = {Kaempferol Inhibits the Primary Attachment Phase of Biofilm Formation in Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2263}, pmid = {29187848}, issn = {1664-302X}, support = {U18 FD005013/FD/FDA HHS/United States ; }, abstract = {The ability to form biofilms on surfaces makes Staphylococcus aureus the main pathogenic factor in implanted medical device infections. The aim of this study was to discover a biofilm inhibitor distinct from the antibiotics used to prevent infections resulting from S. aureus biofilms. Here, we describe kaempferol, a small molecule with anti-biofilm activity that specifically inhibited the formation of S. aureus biofilms. Crystal violet (CV) staining and fluorescence microscopy clearly showed that 64 μg/ml kaempferol inhibited biofilm formation by 80%. Meanwhile, the minimum inhibitory concentration (MIC) and growth curve results indicated that kaempferol had no antibacterial activity against the tested bacterial strain. Kaempferol inhibited the primary attachment phase of biofilm formation, as determined by a fibrinogen-binding assay. Moreover, a fluorescence resonance energy transfer (FRET) assay and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analyses revealed that kaempferol reduced the activity of S. aureus sortaseA (SrtA) and the expression of adhesion-related genes. Based on these results, kaempferol provides a starting point for the development of novel anti-biofilm drugs, which may decrease the risk of bacterial drug resistance, to prevent S. aureus biofilm-related infections.}, } @article {pmid29187716, year = {2017}, author = {Okamoto-Shibayama, K and Kikuchi, Y and Kokubu, E and Ishihara, K}, title = {[Possible Involvement of Surface Antigen Protein 2 in the Morphological Transition and Biofilm Formation of Candida albicans].}, journal = {Medical mycology journal}, volume = {58}, number = {4}, pages = {E139-E143}, doi = {10.3314/mmj.17-00008}, pmid = {29187716}, issn = {1882-0476}, mesh = {Antigens, Surface/genetics/*metabolism ; Biofilms/*growth & development ; Candida albicans/genetics/growth & development/*pathogenicity/*physiology ; Fungal Proteins/genetics/*metabolism ; Virulence/genetics ; }, abstract = {Surface antigen protein 2 (Csa2) is a member of the Candida albicans Common in Fungal Extracellular Membranes (CFEM) protein superfamily. We previously established its role in iron acquisition in C. albicans. However, the other roles of Csa2 remain unknown. Here, we compared growth, morphological transition, and biofilm formation among wild-type, Csa2-mutant, and complemented strains of C. albicans. Deletion of the Csa2 gene resulted in smaller and reduced colony growth, significant attenuation of the dimorphic transition under serum-inducing conditions, and reduced biofilm formation; complementation restored these levels to those of the wild-type. Our findings demonstrated that Csa2 participated in yeast-to-hyphae morphological switching under serum-inducing conditions and contributed to the biofilm formation of C. albicans. This work, therefore, provides novel insights into the potential roles of Csa2 in virulence of C. albicans.}, } @article {pmid29186017, year = {2017}, author = {Paz-Méndez, AM and Lamas, A and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM}, title = {Effect of Food Residues in Biofilm Formation on Stainless Steel and Polystyrene Surfaces by Salmonella enterica Strains Isolated from Poultry Houses.}, journal = {Foods (Basel, Switzerland)}, volume = {6}, number = {12}, pages = {}, pmid = {29186017}, issn = {2304-8158}, abstract = {Salmonella spp. is a major food-borne pathogen around the world. The ability of Salmonella to produce biofilm is one of the main obstacles in reducing the prevalence of these bacteria in the food chain. Most of Salmonella biofilm studies found in the literature used laboratory growth media. However, in the food chain, food residues are the principal source of nutrients of Salmonella. In this study, the biofilm formation, morphotype, and motility of 13 Salmonella strains belonging to three different subspecies and isolated from poultry houses was evaluated. To simulate food chain conditions, four different growth media (Tryptic Soy Broth at 1/20 dilution, milk at 1/20 dilution, tomato juice, and chicken meat juice), two different surfaces (stainless steel and polystyrene) and two temperatures (6 °C and 22 °C) were used to evaluate the biofilm formation. The morphotype, motility, and biofilm formation of Salmonella was temperature-dependent. Biofilm formation was significantly higher with 1/20 Tryptic Soy Broth in all the surfaces and temperatures tested, in comparison with the other growth media. The laboratory growth medium 1/20 Tryptic Soy Broth enhanced biofilm formation in Salmonella. This could explain the great differences in biofilm formation found between this growth medium and food residues. However, Salmonella strains were able to produce biofilm on the presence of food residues in all the conditions tested. Therefore, the Salmonella strain can use food residues to produce biofilm on common surfaces of the food chain. More studies combining more strains and food residues are necessary to fully understand the mechanism used by Salmonella to produce biofilm on the presence of these sources of nutrients.}, } @article {pmid29185603, year = {2017}, author = {Oliveira, PRA and Coutinho, TCL and Portela, MB and Paula, VCA and Tostes, MA}, title = {Influence of biofilm formation on the mechanical properties of enamel after treatment with CPP-ACP crème.}, journal = {Brazilian oral research}, volume = {31}, number = {}, pages = {e84}, doi = {10.1590/1807-3107BOR-2017.vol31.0084}, pmid = {29185603}, issn = {1807-3107}, mesh = {Biofilms/drug effects/*growth & development ; Cariostatic Agents/*chemistry ; Caseins/*chemistry ; Dental Enamel/*drug effects/*microbiology ; Dentifrices/chemistry ; Fluorides/*chemistry ; Hardness Tests ; Humans ; Materials Testing ; Reference Values ; Reproducibility of Results ; Saliva, Artificial/chemistry ; Statistics, Nonparametric ; Streptococcus mutans/drug effects/*physiology ; Surface Properties ; Time Factors ; Tooth Remineralization/methods ; }, abstract = {The study aimed to investigate the effects of bacterial biofilms on changes in the surface microhardness of enamel treated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) with and without fluoride. Human enamel blocks with incipient caries-like lesions were divided into four groups of 13: G1: Saliva (Control); G2: fluoride dentifrice (Crest™, 1100 ppm as NaF); G3: CPP-ACP (MI Paste; Recaldent™); and G4: CPP-ACPF (MI Paste Plus; Recaldent™ 900 ppm as NaF). The specimens were soaked in demineralizing solution for 6 h and remineralized in artificial saliva for 18 h alternately for 10 days. The dentifrice was prepared with deionized water in a 1 : 3 ratio (w/w) or applied undiluted in the case of the CPP-ACP group. The surface microhardness (SMH) was evaluated at baseline, after artificial caries, after pH cycling and treatment with dentifrices, and after incubation in media with Streptococcus mutans for biofilm formation. The biofilms were exposed once a day to 2% sucrose and the biofilm viability was measured by MTT reduction. The percentage of change in surface microhardness (%SMHC) was calculated for each block. The data were analyzed by nonparametric test comparisons (α = 0.05). The %SMHC values observed in G2 were different from those of G1, G3, and G4 (p < 0.05). After biofilm formation, %SMHC was positive in G2 and G4 when compared to G1 and G3, but resistance to demineralization after biofilm formation was similar in all groups. In conclusion, the presence of biofilms did not influence the treatment outcomes of anticaries products.}, } @article {pmid29185466, year = {2017}, author = {Ko, SJ and Kim, MK and Bang, JK and Seo, CH and Luchian, T and Park, Y}, title = {Macropis fulvipes Venom component Macropin Exerts its Antibacterial and Anti-Biofilm Properties by Damaging the Plasma Membranes of Drug Resistant Bacteria.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {16580}, pmid = {29185466}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*chemistry/metabolism/*pharmacology ; Antimicrobial Cationic Peptides/pharmacology ; Bee Venoms/chemistry/pharmacology ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Drug Resistance, Multiple, Bacterial ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Lipopolysaccharides/metabolism ; Microbial Sensitivity Tests ; Peptidoglycan/metabolism ; }, abstract = {The abuse of antibiotics for disease treatment has led to the emergence of multidrug resistant bacteria. Antimicrobial peptides, found naturally in various organisms, have received increasing interest as alternatives to conventional antibiotics because of their broad spectrum antimicrobial activity and low cytotoxicity. In a previous report, Macropin, isolated from bee venom, exhibited antimicrobial activity against both gram-positive and negative bacteria. In the present study, Macropin was synthesized and its antibacterial and anti-biofilm activities were tested against bacterial strains, including gram-positive and negative bacteria, and drug resistant bacteria. Moreover, Macropin did not exhibit hemolytic activity and cytotoxicity to keratinocytes, whereas Melittin, as a positive control, showed very high toxicity. Circular dichroism assays showed that Macropin has an α-helical structure in membrane mimic environments. Macropin binds to peptidoglycan and lipopolysaccharide and kills the bacteria by disrupting their membranes. Moreover, the fractional inhibitory concentration index indicated that Macropin has additive and partially synergistic effects with conventional antibiotics against drug resistant bacteria. Thus, our study suggested that Macropin has potential for use of an antimicrobial agent for infectious bacteria, including drug resistant bacteria.}, } @article {pmid29184101, year = {2017}, author = {Herschend, J and Damholt, ZBV and Marquard, AM and Svensson, B and Sørensen, SJ and Hägglund, P and Burmølle, M}, title = {A meta-proteomics approach to study the interspecies interactions affecting microbial biofilm development in a model community.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {16483}, pmid = {29184101}, issn = {2045-2322}, mesh = {Amino Acids/metabolism ; Bacteria/growth & development/metabolism ; *Biofilms ; Colony Count, Microbial ; Energy Metabolism ; Mass Spectrometry ; *Microbial Interactions ; Nitrogen/metabolism ; *Proteome ; *Proteomics/methods ; }, abstract = {Microbial biofilms are omnipresent in nature and relevant to a broad spectrum of industries ranging from bioremediation and food production to biomedical applications. To date little is understood about how multi-species biofilm communities develop and function on a molecular level, due to the complexity of these biological systems. Here we apply a meta-proteomics approach to investigate the mechanisms influencing biofilm formation in a model consortium of four bacterial soil isolates; Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus. Protein abundances in community and single species biofilms were compared to describe occurring inter-species interactions and the resulting changes in active metabolic pathways. To obtain full taxonomic resolution between closely related species and empower correct protein quantification, we developed a novel pipeline for generating reduced reference proteomes for spectral database searches. Meta-proteomics profiling indicated that community development is dependent on cooperative interactions between community members facilitating cross-feeding on specific amino acids. Opposite regulation patterns of fermentation and nitrogen pathways in Paenibacillus amylolyticus and Xanthomonas retroflexus may, however, indicate that competition for limited resources also affects community development. Overall our results demonstrate the multitude of pathways involved in biofilm formation in mixed communities.}, } @article {pmid29183674, year = {2018}, author = {Han, A and Tsoi, JKH and Matinlinna, JP and Zhang, Y and Chen, Z}, title = {Effects of different sterilization methods on surface characteristics and biofilm formation on zirconia in vitro.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {34}, number = {2}, pages = {272-281}, pmid = {29183674}, issn = {1879-0097}, support = {R01 DE017925/DE/NIDCR NIH HHS/United States ; R01 DE026279/DE/NIDCR NIH HHS/United States ; R01 DE026772/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Color ; Materials Testing ; Microscopy, Electron, Scanning ; Photoelectron Spectroscopy ; Porphyromonas gingivalis ; Staphylococcus aureus ; Stem Cells ; Sterilization/*methods ; Surface Properties ; X-Ray Diffraction ; Zirconium/*chemistry ; }, abstract = {OBJECTIVE: The current laboratory study was to investigate the effect of different sterilization treatments on surface characteristics of zirconia, and biofilm formation on zirconia surface after exposure to these sterilization treatments.

METHODS: Commercially available zirconia discs (Cerconbase, Degu-Dent, Hanau, Germany) were prepared and polished to the same value of surface roughness. The discs were treated with one of the following sterilization methods steam autoclave sterilization, dry heat sterilization, ultraviolet C (UVC) irradiation, and gamma (γ) ray irradiation. The characteristics of zirconia surfaces were evaluated by scanning electron microscopy (SEM), surface roughness, surface free energy (SFE), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) measurements. Then, Staphylococcus aureus (S.a.) and Porphyromonas gingivalis (P.g.) bacteria were used and cultured on the respective sterilized zirconia surfaces. The amount of biofilm formation on zirconia surface was quantified by colony forming unit (CFU) counts.

RESULTS: Significant modifications were detected on the colour and SFE of zirconia. The colour of zirconia samples after UVC irradiation became light yellow whilst dark brown colour was observed after gamma ray irradiation. Moreover, UVC and gamma ray irradiation increased the hydrophilicity of zirconia surface. Overall, dry heat sterilized samples showed the significantly lowest amount of bacteria growth on zirconia, while UVC and gamma ray irradiation resulted in the highest.

SIGNIFICANCE: It is evident that various sterilization methods could change the surface which contribute to different biofilm formation and colour on zirconia.}, } @article {pmid29182966, year = {2018}, author = {Carrillo, U and Díaz-Villanueva, V and Modenutti, B}, title = {Sustained effects of volcanic ash on biofilm stoichiometry, enzyme activity and community composition in North- Patagonia streams.}, journal = {The Science of the total environment}, volume = {621}, number = {}, pages = {235-244}, doi = {10.1016/j.scitotenv.2017.11.270}, pmid = {29182966}, issn = {1879-1026}, mesh = {Argentina ; *Biofilms ; Chile ; Cyanobacteria ; Diatoms ; Ecosystem ; *Environmental Monitoring ; Enzymes/*metabolism ; Phosphorus/analysis ; Rivers/*microbiology ; *Volcanic Eruptions ; }, abstract = {Volcanic eruptions are extreme perturbations that affect ecosystems. These events can also produce persistent effects in the environment for several years after the eruption, with increased concentrations of suspended particles and the introduction of elements in the water column. On 4th June 2011, the Puyehue-Cordón Caulle Volcanic Complex (40.59°S-72.11°W, 2200m.a.s.l.) erupted explosively in southern Chile. The area affected by the volcano was devastated; a thick layer of volcanic ash (up to 30cm) was deposited in areas 50 km east of the volcano towards Argentina. The aim of the present study was to evaluate the effect of volcanic ash deposits on stream ecosystems four years after the eruption, comparing biofilm stoichiometry, alkaline phosphatase activity, and primary producer's assemblage in streams which were severely affected by the volcano with unaffected streams. We confirmed in the laboratory that ash deposited in the catchment of affected streams still leach phosphorus (P) into the water four years after eruption. Results indicate that affected streams still receive volcanic particles and that these particles release P, thus stream water exhibits high P concentration. Biofilm P content was higher and the C:P ratio lower in affected streams compared to unaffected streams. As a consequence of less P in unaffected streams, the alkaline phosphatase activity was higher compared to affected streams. Cyanobacteria increased their abundances (99.9% of total algal biovolume) in the affected streams suggesting that the increase in P may positively affect this group. On the contrary, unaffected streams contained a diatom dominant biofilm. In this way, local heterogeneity was created between sub-catchments located within 30 km of each other. These types of events should be seen as opportunities to gather valuable ecological information about how severe disturbances, like volcanic eruptions, shape landscapes and lotic systems for several years after the event.}, } @article {pmid29180990, year = {2017}, author = {Fais, R and Di Luca, M and Rizzato, C and Morici, P and Bottai, D and Tavanti, A and Lupetti, A}, title = {The N-Terminus of Human Lactoferrin Displays Anti-biofilm Activity on Candida parapsilosis in Lumen Catheters.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2218}, pmid = {29180990}, issn = {1664-302X}, abstract = {Candida parapsilosis is a major cause of hospital-acquired infection, often related to parenteral nutrition administered via catheters and hand colonization of health care workers, and its peculiar biofilm formation ability on plastic surfaces. The mortality rate of 30% points to the pressing need for new antifungal drugs. The present study aimed at analyzing the inhibitory activity of the N-terminal lactoferrin-derived peptide, further referred to as hLF 1-11, against biofilms produced by clinical isolates of C. parapsilosis characterized for their biofilm forming ability and fluconazole susceptibility. hLF 1-11 anti-biofilm activity was assessed in terms of reduction of biofilm biomass, metabolic activity, and observation of sessile cell morphology on polystyrene microtiter plates and using an in vitro model of catheter-associated C. parapsilosis biofilm production. Moreover, fluctuation in transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production upon peptide exposure were evaluated by quantitative real time RT-PCR. The results revealed that hLF 1-11 exhibits an inhibitory effect on biofilm formation by all the C. parapsilosis isolates tested, in a dose-dependent manner, regardless of their fluconazole susceptibility. In addition, hLF 1-11 induced a statistically significant dose-dependent reduction of preformed-biofilm cellular density and metabolic activity at high peptide concentrations only. Interestingly, when assessed in a catheter lumen, hLF 1-11 was able to induce a 2-log reduction of sessile cell viability at both the peptide concentrations used in RPMI diluted in NaPB. A more pronounced anti-biofilm effect was observed (3.5-log reduction) when a 10% glucose solution was used as experimental condition on both early and preformed C. parapsilosis biofilm. Quantitative real time RT-PCR experiments confirmed that hLF 1-11 down-regulates key biofilm related genes. The overall findings suggest hLF 1-11 as a promising candidate for the prevention of C. parapsilosis biofilm formation and to treatment of mature catheter-related C. parapsilosis biofilm formation.}, } @article {pmid29180529, year = {2018}, author = {Poudyal, B and Sauer, K}, title = {The ABC of Biofilm Drug Tolerance: the MerR-Like Regulator BrlR Is an Activator of ABC Transport Systems, with PA1874-77 Contributing to the Tolerance of Pseudomonas aeruginosa Biofilms to Tobramycin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {2}, pages = {}, pmid = {29180529}, issn = {1098-6596}, support = {R01 AI075257/AI/NIAID NIH HHS/United States ; R01 AI080710/AI/NIAID NIH HHS/United States ; }, mesh = {ATP-Binding Cassette Transporters/*genetics ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*drug effects ; Cells, Cultured ; Drug Tolerance/*genetics ; Gene Expression Regulation, Bacterial/drug effects/genetics ; Microbial Sensitivity Tests/methods ; Plankton/microbiology ; Protein Transport/drug effects/genetics ; Pseudomonas aeruginosa/*drug effects/genetics ; Tobramycin/*pharmacology ; Transcription, Genetic/drug effects/genetics ; }, abstract = {A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa, biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77. Insertional inactivation of the 7 ABC transport systems rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin or norfloxacin. Susceptibility was linked to drug accumulation, with BrlR contributing to norfloxacin accumulation in a manner dependent on multidrug efflux pumps and the PA1874-77 ABC transport system. Inactivation of the respective ABC transport system, furthermore, eliminated the recalcitrance of biofilms to killing by tobramycin but not norfloxacin, indicating that drug accumulation is not linked to biofilm drug tolerance. Our findings indicate for the first time that BrlR, a MerR-type transcriptional activator, activates genes encoding several ABC transport systems, in addition to multiple multidrug efflux pump genes. Moreover, our data confirm a BrlR target contributing to drug tolerance, likely countering the prevailing dogma that biofilm tolerance arises from a multiplicity of factors.}, } @article {pmid29178841, year = {2017}, author = {Yang, X and Qian, S and Yao, K and Wang, L and Liu, Y and Dong, F and Song, W and Zhen, J and Zhou, W and Xu, H and Zheng, H and Li, W}, title = {Multiresistant ST59-SCCmec IV-t437 clone with strong biofilm-forming capacity was identified predominantly in MRSA isolated from Chinese children.}, journal = {BMC infectious diseases}, volume = {17}, number = {1}, pages = {733}, pmid = {29178841}, issn = {1471-2334}, support = {81571948//National Natural Science Foundation of China/International ; 7172075//Natural Science Foundation of Beijing Municipality (CN)/International ; }, mesh = {Adolescent ; Biofilms ; Child ; Child, Preschool ; China/epidemiology ; Drug Resistance, Multiple, Bacterial/drug effects/*genetics ; Female ; Humans ; Infant ; Infant, Newborn ; Linezolid/pharmacology ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/isolation & purification ; Microbial Sensitivity Tests ; Multilocus Sequence Typing/methods ; Mupirocin/pharmacology ; Staphylococcal Infections/drug therapy/epidemiology/*microbiology ; Staphylococcus aureus/*drug effects/isolation & purification/*physiology ; Trimethoprim, Sulfamethoxazole Drug Combination ; }, abstract = {BACKGROUND: This study aimed to investigate the clinical and molecular epidemiology and biofilm formation of Staphylococcus aureus (SA) isolated from pediatricians in China.

METHODS: SA strains were isolated from Beijing Children's hospital from February 2016 to January 2017. Isolates were typed by multilocus sequence typing (MLST), spa and SCCmec typing (for Methicillin-resistant SA [MRSA] only). Antimicrobial susceptibility testing was performed by agar dilution method except sulphamethoxazole/trimethoprim (E-test method). Biofilm formation and biofilm associated genes were detected.

RESULTS: Totally 104 children (41 females and 63 males; median age, 5.2 months) were enrolled in this study, in which 60 patients suffered from MRSA infection. Among the 104 cases, 54.8% were categorized as community associated SA (CA-SA) infections. The children under 3 years were more likely to occur CA-SA infections compared with older ones (P = 0.0131). ST59-SCCmec IV-t437 (61.7%) was the most prevalent genotype of MRSA, and ST22-t309 (18.2%), ST5-t002 (9.1%), ST6-t701 (9.1%), ST188-t189 (9.1%) were the top four genotypes of methicillin-sensitive SA (MSSA). All the present isolates were susceptible to linezolid, vancomycin, trimethoprim-sulfamethoxazole, mupirocin, tigecyclin, fusidic acid. No erythromycin-susceptible isolate was determined, and only a few isolates (3.8%) were identified as susceptible to penicillin. Multi-drug resistant isolates were reponsible for 83.8% of the ST59-SCCmec IV-t437 isolates. The isolates with strong biofilm formation were found in 85% of MRSA and 53.2% of MSSA, and in 88.7% of ST59-SCCmec IV-t437 isolates. Biofilm formation ability varied not only between MRSA and MSSA (P = 0.0053), but also greatly among different genotypes (P < 0.0001). The prevalence of the biofilm associated genes among ST59-SCCmec IV-t437 clone was: icaA (100.0%), icaD (97.3%), fnbpA (100.0%), fnbpB (0), clfA (100%), clfB (100%), cna (2.7%), bbp (0), ebpS (88.5%), sdrC (78.4%), sdrD (5.4%), and sdrE (94.5%).

CONCLUSIONS: These results indicated strong homology of the MRSA stains isolated from Chinese children, which was caused by spread of multiresistant ST59-SCCmec IV-t437 clone with strong biofilm formation ability. The MSSA strains, in contrast, were very heterogeneity, half of which could produce biofilm strongly.}, } @article {pmid29178741, year = {2016}, author = {de Oliveira Becci, AC and Marti, LM and Cilense Zuanon, AC and Brighenti, FL and Palomari Spolidório, DM and Aparecida Giro, EM}, title = {Analysis of the biofilm formed on the surface of a glass-ionomer cement associated with different concentrations of chlorhexidine diacetate.}, journal = {American journal of dentistry}, volume = {29}, number = {5}, pages = {277-281}, pmid = {29178741}, issn = {0894-8275}, mesh = {Adult ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; Cross-Over Studies ; Double-Blind Method ; Glass Ionomer Cements/*pharmacology ; Humans ; Lactobacillus/isolation & purification ; Materials Testing ; Streptococcus/isolation & purification ; Surface Properties ; }, abstract = {PURPOSE: This cross-over in situ experiment evaluated the microbial composition and quantified the total polysaccharides in the biofilm formed on the surface of a high viscosity glass-ionomer cement (GIC) mixed with chlorhexidine diacetate (CHX) in concentrations of 0.5%, 1% and 2%. GIC without CHX was used as control.

METHODS: The volunteers (n= 8) tested each material for a 7-day period, by using a palatal acrylic device containing four round specimens, all fabricated with the same material. An increasing order of CHX concentration and a 15-day washout period between each concentration was adopted. The biofilm formed was collected and inoculated in specific culture media and thereafter, the total microorganisms, total streptococci, Streptococcus mutans and Lactobacillus spp were counted. Total polysaccharides were quantified by using a phenol-sulfuric method. Microbiologic data were analyzed by ANOVA for repeated measures and Tukey tests, and the total polysaccharide content by Friedman and Dunn's tests. Significance level was set at 5%.

RESULTS: Microorganism counts showed statistically significant differences among groups only for Lactobacillus (P< 0.05), that were significantly higher for group GIC+CHX 2% compared with GIC and GIC+CHX 0.5%. However, the concentration of total polysaccharides in the biofilm was lower for groups containing 1% and 2% of CHX.

CLINICAL SIGNIFICANCE: The addition of chlorhexidine in the studied concentrations did not reduce the microorganism counts, but caused reduction of biofilm density.}, } @article {pmid29178733, year = {2017}, author = {Pinna, R and Usai, P and Filigheddu, E and Garcia-Godoy, F and Milia, E}, title = {The role of adhesive materials and oral biofilm in the failure of adhesive resin restorations.}, journal = {American journal of dentistry}, volume = {30}, number = {5}, pages = {285-292}, pmid = {29178733}, issn = {0894-8275}, mesh = {*Biofilms ; Composite Resins ; Dental Bonding ; Dental Cavity Preparation ; Dental Cements ; Dental Enamel ; Dental Leakage ; *Dental Restoration, Permanent ; Dentin ; *Dentin-Bonding Agents ; Humans ; Materials Testing ; Resin Cements ; }, abstract = {PURPOSE: To critically discuss adhesive materials and oral cariogenic biofilm in terms of their potential relevance to the failures of adhesive restorations in the oral environment.

METHODS: The literature regarding adhesive restoration failures was reviewed with particular emphasis on the chemistry of adhesive resins, weakness in dentin bonding, water fluids, cariogenic oral biofilm and the relations that influence failures. Particular attention was paid to evidence derived from clinical studies.

RESULTS: There was much evidence that polymerization shrinkage is one of the main drawbacks of composite formulations. Stress results in debonding and marginal leakage into gaps with deleterious effects in bond strength, mechanical properties and the whole stability of restorations. Changes in resins permit passage of fluids and salivary proteins with a biological breakdown of the restorations. Esterases enzymes in human saliva catalyze exposed ester groups in composite producing monomer by-products, which can favor biofilm accumulation and secondary caries. Adhesive systems may not produce a dense hybrid layer in dentin. Very often this is related to the high viscous solubility and low wettability in dentin of the hydrophobic BisGMA monomer. Thus, dentin hybrid layer may suffer from hydrolysis using both the Etch&Rinse and Self-Etching adhesive systems. In addition, exposed and non-resin enveloped collagen fibers may be degraded by activation of the host-derived matrix metalloproteinase. Plaque accumulation is significantly influenced by the surface properties of the restorations. Biofilm at the contraction gap has demonstrated increased growth of Streptococcus mutans motivated by the chemical hydrolysis of the adhesive monomers at the margins. Streptococcus mutans is able to utilize some polysaccharides from the biofilm to increase the amount of acid in dental plaque with an increase in virulence and destruction of restorations. Stability of resin restorations in the oral environment is highly dependent on the structure of the monomers used in composite and adhesive systems. Still, the issues related to microleakage of fluids into the gap and bacteria leaching from the surface of composites represent the main causes of failure of adhesive restorations.

CLINICAL SIGNIFICANCE: Modifications of adhesive materials are necessary to address their instability in the oral environment.}, } @article {pmid29178715, year = {2017}, author = {Liu, T and Wu, L and Babu, JP and Hottel, TL and Garcia-Godoy, F and Hong, L}, title = {Effects of atmospheric non-thermal argon/oxygen plasma on biofilm viability and hydrophobicity of oral bacteria.}, journal = {American journal of dentistry}, volume = {30}, number = {1}, pages = {52-56}, pmid = {29178715}, issn = {0894-8275}, mesh = {Argon/*pharmacology ; Atmospheric Pressure ; Biofilms/*drug effects ; Hydrophobic and Hydrophilic Interactions ; In Vitro Techniques ; Microbial Viability/*drug effects ; Microbiota/drug effects ; Oxygen/*pharmacology ; Plasma Gases/*pharmacology ; Streptococcus mutans/*drug effects ; Streptococcus sanguis/*drug effects ; Tetrazolium Salts ; Thiazoles ; }, abstract = {PURPOSE: To evaluate the bactericidal effects of atmospheric non-thermal argon/oxygen plasma on in vitro oral biofilms constructed from S. mutans and/or S. sanguinis, and the influence of the plasma on the virulence properties of A. oris.

METHODS: In vitro oral biofilms were constructed in the wells of 48-well plates from S. mutans and/or S. sanguinis. The wells containing constructed biofilms and various amounts of phosphate-buffered saline (PBS) were treated with non-thermal argon/oxygen plasma brush for 2 minutes. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and Live/Dead assay were used to evaluate the viability of biofilms in those wells after the plasma treatments. Meanwhile, A. oris suspensions were treated with the plasma and then evaluated for their virulence properties by measuring the hydrophobicity and co-aggregation capability of treated A. oris.

RESULTS: The MTT assay showed that exposure to non-thermal plasma for 2 minutes significantly reduced the viability of bacteria in both single-species and two-species biofilms of S. mutans and S. sanguinis with the reductions of up to 99%. Meanwhile, plasma treatment also altered the hydrophobicity of A. oris, and reduced their capability to co-aggregate with S. sanguinis.

CLINICAL SIGNIFICANCE: The results from this study demonstrated that atmospheric non-thermal argon/oxygen plasma could effectively deactivate oral bacteria biofilm by decreasing bacterial viability as well as reducing their hydrophobicity and co-aggregation capability.}, } @article {pmid29178668, year = {2018}, author = {Trøstrup, H and Lerche, CJ and Christophersen, LJ and Thomsen, K and Jensen, PØ and Hougen, HP and Høiby, N and Moser, C}, title = {Pseudomonas aeruginosa biofilm hampers murine central wound healing by suppression of vascular epithelial growth factor.}, journal = {International wound journal}, volume = {15}, number = {1}, pages = {123-132}, pmid = {29178668}, issn = {1742-481X}, mesh = {Animals ; Biofilms/*growth & development ; Burns/*microbiology/*physiopathology ; Chronic Disease ; Disease Models, Animal ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C3H ; Pseudomonas Infections/*complications ; Pseudomonas aeruginosa/*physiology ; Vascular Endothelial Growth Factor A/*physiology ; Wound Healing/physiology ; Wound Infection/*microbiology ; }, abstract = {Biofilm-infected wounds are clinically challenging. Vascular endothelial growth factor and host defence S100A8/A9 are crucial for wound healing but may be suppressed by biofilms. The natural course of Pseudomonas aeruginosa biofilm infection was compared in central and peripheral zones of burn-wounded, infection-susceptible BALB/c mice, which display delayed wound closure compared to C3H/HeN mice. Wounds were evaluated histopathologically 4, 7 or 10 days post-infection. Photoplanimetry evaluated necrotic areas. P. aeruginosa biofilm suppressed vascular endothelial growth factor levels centrally in BALB/c wounds but increased peripheral levels 4-7 days post-infection. Central zones of the burn wound displayed lower levels of central vascular endothelial growth factor as observed 4 and 7 days post-infection in BALB/c mice compared to their C3H/HeN counterparts. Biofilm suppressed early, centrally located S100A8/A9 in BALB/c and centrally and peripherally later on in C3H/HeN wounds as compared to uninfected mice. Peripheral polymorphonuclear-dominated inflammation and larger necrosis were observed in BALB/c wounds. In conclusion, P. aeruginosa biofilm modulates wounds by suppressing central, but inducing peripheral, vascular endothelial growth factor levels and reducing host response in wounds of BALB/c mice. This suppression is detrimental to the resolution of biofilm-infected necrosis.}, } @article {pmid29178633, year = {2018}, author = {Lowrence, RC and Ramakrishnan, A and Sundaramoorthy, NS and Shyam, A and Mohan, V and Subbarao, HMV and Ulaganathan, V and Raman, T and Solomon, A and Nagarajan, S}, title = {Norfloxacin salts of carboxylic acids curtail planktonic and biofilm mode of growth in ESKAPE pathogens.}, journal = {Journal of applied microbiology}, volume = {124}, number = {2}, pages = {408-422}, doi = {10.1111/jam.13651}, pmid = {29178633}, issn = {1365-2672}, mesh = {Acinetobacter baumannii/drug effects/growth & development/physiology ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Carboxylic Acids/chemistry/pharmacology ; Enterobacter/drug effects/growth & development/physiology ; Enterococcus faecium/drug effects/growth & development/physiology ; Escherichia coli/drug effects/growth & development/physiology ; Gram-Negative Aerobic Bacteria/*drug effects/growth & development/physiology ; Gram-Negative Bacterial Infections/*microbiology ; Klebsiella pneumoniae/drug effects/growth & development/physiology ; Microbial Sensitivity Tests ; Norfloxacin/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/growth & development/physiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/growth & development/physiology ; }, abstract = {AIMS: To enhance the antimicrobial and antibiofilm activity of norfloxacin against the planktonic and biofilm mode of growth in ESKAPE pathogens using chemically modified norfloxacin salts.

METHODS AND RESULTS: Antimicrobial testing, synergy testing and time-kill curve analysis were performed to evaluate antibacterial effect of norfloxacin carboxylic acid salts against ESKAPE pathogens. In vivo efficacy to reduce bacterial bioburden was evaluated in zebrafish infection model. Crystal violet assay and live-dead staining were performed to discern antibiofilm effect. Membrane permeability, integrity and molecular docking studies were carried out to ascertain the mechanism of action. The carboxylic acid salts, relative to parent molecule norfloxacin, displayed two- to fourfold reduction in minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to displaying potent bacteriostatic effect against certain members of ESKAPE pathogens. In vivo treatments revealed that norfloxacin tartrate (SRIN2) reduced MRSA bioburden by greater than 1 log fold relative to parent molecule in the muscle tissue. In silico docking with gyrA of S. aureus showed increased affinity of SRIN2 towards DNA gyrase. The enhanced antibacterial effect of norfloxacin salts could be partially accounted by altered membrane permeability in S. aureus and perturbed membrane integrity in P. aeruginosa. Antibiofilm studies revealed that SRIN2 (norfloxacin tartrate) and SRIN3 (norfloxacin benzoate) exerted potent antibiofilm effect particularly against Gram-negative ESKAPE pathogens. The impaired colonization of both S. aureus and P. aeruginosa due to improved norfloxacin salts was further supported by live-dead imaging.

CONCLUSION: Norfloxacin carboxylic acid salts can act as potential alternatives in terms of drug resensitization and reuse.

Our study shows that carboxylic acid salts of norfloxacin could be effectively employed to treat both planktonic- and biofilm-based infections caused by select members of ESKAPE pathogens.}, } @article {pmid29178590, year = {2018}, author = {She, P and Wang, Y and Luo, Z and Chen, L and Tan, R and Wang, Y and Wu, Y}, title = {Meloxicam inhibits biofilm formation and enhances antimicrobial agents efficacy by Pseudomonas aeruginosa.}, journal = {MicrobiologyOpen}, volume = {7}, number = {1}, pages = {}, pmid = {29178590}, issn = {2045-8827}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Dose-Response Relationship, Drug ; *Drug Synergism ; Locomotion/drug effects ; Meloxicam ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/*physiology ; Quorum Sensing/drug effects ; Thiazines/*pharmacology ; Thiazoles/*pharmacology ; Virulence Factors/antagonists & inhibitors ; }, abstract = {Microbial biofilms are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Bacterial cells in biofilm are 10~1,000-fold more resistant to antimicrobials than the planktonic cells. Burgeoning antibiotic resistance in Pseudomonas aeruginosa biofilm has necessitated the development of antimicrobial agents. Here, we have investigated the antibiofilm effect of meloxicam against P. aeruginosaPAO1 and its potential mechanisms. Further, we have explored whether meloxicam could enhance the susceptibility of bacterial biofilms to treatment with conventional antimicrobials. Here, we found that meloxicam could significantly inhibit PAO1 biofilm formation in a dose-dependent manner at the concentration without influence on planktonic cell growth. Meloxicam could also significantly inhibit the motilities, production of extracellular matrix, and expression of quorum sensing-related genes and virulence factors of PAO1. Furthermore, synergistic interaction was observed when meloxicam combined with tetracycline, gentamicin, tobramycin, ciprofloxacin, ceftriaxone, ofloxacin, norfloxacin, ceftazidime, and DNase at subminimal inhibitory concentrations against PAO1 bioiflm. Collectively, our study lays the foundation for further investigation of repurposing meloxicam as a topical antibiofilm agent to treat P. aeruginosa biofilm-related infections.}, } @article {pmid29178348, year = {2018}, author = {Mohmmed, SA and Vianna, ME and Penny, MR and Hilton, ST and Mordan, NJ and Knowles, JC}, title = {Investigations into in situ Enterococcus faecalis biofilm removal by passive and active sodium hypochlorite irrigation delivered into the lateral canal of a simulated root canal model.}, journal = {International endodontic journal}, volume = {51}, number = {6}, pages = {649-662}, doi = {10.1111/iej.12880}, pmid = {29178348}, issn = {1365-2591}, mesh = {Biofilms/*drug effects ; Dental Pulp Cavity/*microbiology ; *Enterococcus faecalis ; Microscopy, Electron, Scanning ; Models, Dental ; Printing, Three-Dimensional ; Sodium Hypochlorite/*pharmacology ; Sonication ; Therapeutic Irrigation/*methods ; }, abstract = {AIM: To investigate in situ Enterococcus faecalis biofilm removal from the lateral canal of a simulated root canal system using passive or active irrigation protocols.

METHODOLOGY: Root canal models (n = 43) were manufactured from transparent resin materials using 3D printing. Each canal was created with an 18 mm length, apical size 30, a .06 taper and a lateral canal of 3 mm length, with 0.3 mm diameter. Biofilms were grown in the lateral canal and apical 3 mm of the main canal for 10 days. Three models from each group were examined for residual biofilm using SEM. The other forty models were divided into four groups (n = 10). The models were observed under a fluorescence microscope. Following 60 s of 9 mL of 2.5% NaOCl irrigation using syringe and needle, the irrigant was either left stagnant in the canal or activated using gutta-percha, sonic or ultrasonic methods for 30 s. Images were then captured every second using an external camera. The residual biofilm percentages were measured using image analysis software. The data were analysed using generalized linear mixed models. A significance level of 0.05 was used throughout.

RESULTS: The greatest level of biofilm removal was obtained with ultrasonic agitation (66.76%) followed by sonic (45.49%), manual agitation (43.97%) and passive irrigation groups (38.67%), respectively. The differences were significant between the residual biofilm in the passive irrigation and both sonic and ultrasonic groups (P = 0.001).

CONCLUSION: Agitation resulted in better penetration of 2.5% NaOCl into the lateral canal of an artificial root canal model. Ultrasonic agitation of NaOCl improved the removal of biofilm.}, } @article {pmid29177780, year = {2018}, author = {Qian, H and Cheng, Y and Yang, C and Wu, S and Zeng, G and Xi, J}, title = {Performance and biofilm characteristics of biotrickling filters for ethylbenzene removal in the presence of saponins.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {30}, pages = {30021-30030}, pmid = {29177780}, issn = {1614-7499}, support = {51478172, 51278464, 51521006//National Natural Science Foundation of China/ ; LY17E080002//Natural Science Foundation of Zhejiang Province of China/ ; 2017JJ2029//Natural Science Foundation of Hunan Province of China/ ; kh1601187//Department of Science and Technology of Changsha City of China/ ; }, mesh = {Benzene Derivatives/*chemistry ; Biodegradation, Environmental ; Filtration/*methods ; Hydrophobic and Hydrophilic Interactions ; Saponins/*chemistry ; Surface-Active Agents/chemistry ; Volatile Organic Compounds/chemistry ; }, abstract = {Saponins were applied to enhance ethylbenzene removal in biotrickling filters (BTFs), and comparison experiments were carried out to evaluate the effects of saponins on ethylbenzene removal and biofilm characteristics at various saponin concentrations. Results showed that the optimum concentration of saponins was 40 mg/L and a maximum removal efficiency (RE) of ethylbenzene reached 84.3%. When the inlet ethylbenzene concentration increased, ranging from 750 to 2300 mg/m[3], the RE decreased from 92.1 to 60.8% and from 69.4 to 44.2% for BTF1 and BTF2 in which saponin was and was not added, respectively. The corresponding RE declined from 91.1 to 40.8% and from 71.5 to 35.8% with a decreased empty bed residence time ranging from 45 to 7.5 s. Additionally, significant differences existed between both BTFs not only in the contents of polysaccharide and proteins but also in the surface charge of biofilms, and the ratio of protein to polysaccharide increased with the increase of saponin concentration, which indicated the presumable effect of saponins on liquid-biofilm transfer rates of ethylbenzene. Mechanisms for the enhanced removal of hydrophobic volatile organic compounds at the presence of surfactants were also discussed.}, } @article {pmid29174702, year = {2018}, author = {Bhardwaj, RG and Al-Khabbaz, A and Karched, M}, title = {Cytokine induction of peripheral blood mononuclear cells by biofilms and biofilm supernatants of Granulicatella and Abiotrophia spp.}, journal = {Microbial pathogenesis}, volume = {114}, number = {}, pages = {90-94}, doi = {10.1016/j.micpath.2017.11.037}, pmid = {29174702}, issn = {1096-1208}, mesh = {Abiotrophia/*immunology ; Arachidonic Acids/metabolism ; *Biofilms ; Carnobacteriaceae/*immunology ; Chemokine CCL3/metabolism ; Chemokine CCL4/metabolism ; Chemokines/metabolism ; Cytokines/*metabolism ; Endocarditis, Bacterial/microbiology ; Humans ; Interleukin-17/metabolism ; Interleukin-1beta/metabolism ; Interleukin-6/metabolism ; Interleukin-8/metabolism ; Leukocytes, Mononuclear/*metabolism ; Peptide Fragments/metabolism ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {Granulicatella and Abiotrophia species are the normal oral flora bacteria that can occasionally cause infective endocarditis. Although substantial data exists in the literature demonstrating occurrence of these species in infective endocarditis, only a few mechanistic studies on their pathogenicity are found. The aim of this study was to investigate the ability of Granulicatella and Abiotrophia species to elicit immune response from human peripheral blood mononuclear cells (PBMC). Biofilms and biofilm supernatants of Granulicatella elegans CCUG 38949, Granulicatella adiacens CCUG 27809 and Abiotrophia defectiva CCUG 27639 were used to stimulate PBMCs for 24 h. Cytokines produced were first screened using a human cytokine membrane array kit. Further, pro-inflammatory cytokines TNF-α, IL-β, and IL-17 were quantified by ELISA. The cytokine profiler array showed the induction of 15 different cytokines/chemokines including IL-1β, IL-6, IL-8, TNF-α, MCP-1, MIP-1α/MIP-1β and RANTES. ELISA quantification revealed that G. adiacens biofilm induced significantly higher (P < 0.05) levels of IL-1β, i.e., 1931 (183) pg/ml than G. elegans or A. defectiva. However, in the case of biofilm supernatants A. defectiva was the strongest, inducing 2104 (574) pg/ml. Biofilm supernatants, but not biofilms from all three species induced TNF-α only weakly. IL-17 was undetectable from any of the stimulated samples. In conclusion, Granulicatella and Abiotrophia are potent inducers of inflammatory mediators from human PBMCs. However, biofilms and biofilm supernatants from these species seem to selectively elicit stimulation of certain cytokines.}, } @article {pmid29173625, year = {2018}, author = {Dhowlaghar, N and De Abrew Abeysundara, P and Nannapaneni, R and Schilling, MW and Chang, S and Cheng, WH and Sharma, CS}, title = {Biofilm formation by Salmonella spp. in catfish mucus extract under industrial conditions.}, journal = {Food microbiology}, volume = {70}, number = {}, pages = {172-180}, doi = {10.1016/j.fm.2017.09.016}, pmid = {29173625}, issn = {1095-9998}, mesh = {Animals ; *Biofilms ; Catfishes/*microbiology ; Disinfectants/pharmacology ; Equipment Contamination ; Food Handling/*instrumentation ; Mucus/*microbiology ; Salmonella/drug effects/genetics/growth & development/*physiology ; }, abstract = {The objective of this study was to determine the effect of strain and temperature on the growth and biofilm formation of Salmonella spp. in high and low concentrations of catfish mucus extract on different food-contact surfaces at 22 °C and 10 °C. The second objective of this study was to evaluate the efficacy of disinfectants at recommended concentrations and contact times for removing Salmonella biofilms cells on a stainless steel surface containing catfish mucus extract. Growth and biofilm formation of all Salmonella strains increased with higher concentrations of catfish mucus extract at both 10 °C and 22 °C. In 15 μg/ml of catfish mucus extract inoculated with 3 log CFU/ml, the biofilm levels of Salmonella on stainless steel surface reached to 3.5 log CFU/cm[2] at 10 °C or 5.5 log CFU/cm[2] at 22 °C in 7 days. In 375 μg/ml of catfish mucus extract inoculated with 3 log CFU/ml, the biofilm levels of Salmonella on the stainless steel surface reached 4.5 log CFU/cm[2] at 10 °C and 6.5 log CFU/cm[2] at 22 °C in 7 days. No differences were observed between Salmonella strains tested for biofilm formation in catfish mucus extract on the stainless steel surface. The biofilm formation by Salmonella Blockley (7175) in catfish mucus extract was less (P < 0.05) on buna-N rubber when compared to stainless steel, polyethylene and polyurethane surfaces. Salmonella biofilm cells were not detectable on the stainless steel surface after treatment with a mixture of disinfectants but were still present when single compound disinfectants were used.}, } @article {pmid29173057, year = {2018}, author = {Cydzik-Kwiatkowska, A and Zielińska, M}, title = {Microbial composition of biofilm treating wastewater rich in bisphenol A.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {53}, number = {4}, pages = {385-392}, doi = {10.1080/10934529.2017.1404326}, pmid = {29173057}, issn = {1532-4117}, mesh = {Benzhydryl Compounds/*analysis/metabolism ; Biodegradation, Environmental ; Biofilms/*growth & development ; *Microbial Consortia/physiology ; Phenols/*analysis/metabolism ; *Wastewater/chemistry/microbiology ; Water Pollutants, Chemical/*analysis/metabolism ; Water Purification/*methods ; }, abstract = {Although microbial degradation plays a major role in the removal of bisphenol A (BPA) from water environments, there is little information on the effect of BPA on microorganisms in wastewater treatment systems. The aim of this study was to determine the dynamics of the microbial communities in biofilm growing on porous ceramic supports in a column up-flow reactor during exposure to BPA at increasing concentrations from 0 to 10 mg L[-1]. Independent of BPA load, the efficiency of BPA removal was about 90%. Groups of microorganisms that differ in their sensitivity to the presence of BPA in wastewater were identified. The core microbial genera in the biofilm were Acidovorax, Pseudoxanthomonas and Acinetobacter. Arenimonas sp., Thauera sp. and Acidobacterium sp. were the main components of the biofilm in the absence of BPA in wastewater. Increased abundances of Pseudomonas sp., Acidovorax sp. and Luteimonas sp. in BPA-exposed biofilm indicate that these genera may have played important roles in BPA biodegradation. A correlation between Pseudomonas sp. abundance and BPA removal efficiency indicates that BPA was used directly as a source of carbon and energy for growth. This study indicates that the use of the biofilm reactor enables effective BPA removal from wastewater and expands knowledge about the microbial structure of communities responsible for BPA degradation.}, } @article {pmid29172182, year = {2018}, author = {Tang, CC and Tian, Y and Liang, H and Zuo, W and Wang, ZW and Zhang, J and He, ZW}, title = {Enhanced nitrogen and phosphorus removal from domestic wastewater via algae-assisted sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {250}, number = {}, pages = {185-190}, doi = {10.1016/j.biortech.2017.11.028}, pmid = {29172182}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Nitrogen ; *Phosphorus ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {This study proposed a potential strategy for enhancement of nutrients removal from domestic wastewater by adding algae to sequencing batch biofilm reactor (SBBR) to form a novel algal-bacterial symbiosis (ABS) system. Results indicated that the algae-assisted SBBR increased the total nitrogen and phosphorus removal efficiencies from 38.5% to 65.8%, and from 31.9% to 89.3%, respectively. The carriers fixed at the top of the reactor were favorable for both formation of ABS system and algae enrichment. The chlorophyll-a increased to 3.59 mg/g at stable stage, which was 4.07 times higher than that in suspension. Moreover, the bio-carrier replacement and sludge discharge were independent, indicating that the sludge and algae retention time could be separated. The mechanisms analysis suggested that the enhanced nitrogen and phosphorus mainly attributed to the enrichment of both algae biomass and total biomass in biofilm. This study highlights the significance of developing ABS system for wastewater treatment.}, } @article {pmid29169268, year = {2018}, author = {Vázquez-Sánchez, D and Galvão, JA and Oetterer, M}, title = {Contamination sources, biofilm-forming ability and biocide resistance of Staphylococcus aureus in tilapia-processing facilities.}, journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional}, volume = {24}, number = {3}, pages = {209-222}, doi = {10.1177/1082013217742753}, pmid = {29169268}, issn = {1532-1738}, mesh = {Animals ; Aquaculture ; Bacterial Load ; Biofilms/drug effects/*growth & development ; Brazil ; Disinfectants/pharmacology ; Drug Resistance, Multiple, Bacterial ; Enterotoxins/genetics/isolation & purification/metabolism ; Flagellin/genetics/isolation & purification/metabolism ; Food Contamination/*prevention & control ; Food-Processing Industry/*instrumentation ; *Frozen Foods/microbiology ; Microbial Sensitivity Tests ; Molecular Typing ; Peracetic Acid/pharmacology ; Polystyrenes ; *Seafood/microbiology ; Sodium Hypochlorite/pharmacology ; Stainless Steel ; Staphylococcus aureus/classification/drug effects/isolation & purification/*physiology ; *Tilapia/growth & development/microbiology ; Water Microbiology ; }, abstract = {The major contamination sources, biofilm-forming ability and biocide resistance of Staphylococcus aureus in tilapia-processing plants were evaluated. Twenty-five processing control points were analysed twice in two factories, including whole tilapias, frozen fillets, water and food-contact surfaces. No final product was contaminated with S. aureus. However, high concentrations of S. aureus carrying enterotoxin (se) genes were found in several processing points of both factories due to the application of inadequate hygienic and handling procedures, which generate a high risk of cross-contamination of the tilapia fillets with staphylococcal enterotoxins. Nine S. aureus strains were characterized by RAPD-PCR using primers AP-7, ERIC-2 and S. A wide diversity of se gene profiles was detected, most strains being multi- se-carriers. All S. aureus strains showed high biofilm-forming ability on stainless steel and polystyrene. Biofilm-forming ability was correlated with the presence of fliC H7 and the type of origin surface (metallic or plastic). A marked resistance of S. aureus to peracetic acid and sodium hypochlorite was also observed, required doses being higher than those recommended by manufacturers to be eradicated. Case-by-case approaches are thus recommended to determine the sources and degree of contamination present in each factory, which would allow applying precise responses that avoid, or at least reduce, the presence of bacterial pathogens and the emergence of antimicrobial resistance.}, } @article {pmid29165717, year = {2018}, author = {Baslé, A and Hewitt, L and Koh, A and Lamb, HK and Thompson, P and Burgess, JG and Hall, MJ and Hawkins, AR and Murray, H and Lewis, RJ}, title = {Crystal structure of NucB, a biofilm-degrading endonuclease.}, journal = {Nucleic acids research}, volume = {46}, number = {1}, pages = {473-484}, pmid = {29165717}, issn = {1362-4962}, support = {204985/Z/16/Z/WT_/Wellcome Trust/United Kingdom ; BB/K017527/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus licheniformis/genetics/metabolism/*physiology ; Bacterial Proteins/*chemistry/genetics/metabolism ; Biofilms/*growth & development ; Crystallography, X-Ray ; DNA/genetics/metabolism ; Deoxyribonucleases/*chemistry/genetics/metabolism ; Models, Molecular ; Protein Conformation ; }, abstract = {Bacterial biofilms are a complex architecture of cells that grow on moist interfaces, and are held together by a molecular glue of extracellular proteins, sugars and nucleic acids. Biofilms are particularly problematic in human healthcare as they can coat medical implants and are thus a potential source of disease. The enzymatic dispersal of biofilms is increasingly being developed as a new strategy to treat this problem. Here, we have characterized NucB, a biofilm-dispersing nuclease from a marine strain of Bacillus licheniformis, and present its crystal structure together with the biochemistry and a mutational analysis required to confirm its active site. Taken together, these data support the categorization of NucB into a unique subfamily of the ββα metal-dependent non-specific endonucleases. Understanding the structure and function of NucB will facilitate its future development into an anti-biofilm therapeutic agent.}, } @article {pmid29165338, year = {2017}, author = {Koziróg, A and Kręgiel, D and Brycki, B}, title = {Action of Monomeric/Gemini Surfactants on Free Cells and Biofilm of Asaia lannensis.}, journal = {Molecules (Basel, Switzerland)}, volume = {22}, number = {11}, pages = {}, pmid = {29165338}, issn = {1420-3049}, mesh = {Alphaproteobacteria/*drug effects ; Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Calcitriol/*analogs & derivatives/chemistry/pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Molecular Structure ; Surface-Active Agents/*chemistry/*pharmacology ; }, abstract = {We investigated the biological activity of surfactants based on quaternary ammonium compounds: gemini surfactant hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C6), synthesized by the reaction of N,N-dimethyl-N-dodecylamine with 1,6-dibromohexane, and its monomeric analogue dodecyltrimethylammonium bromide (DTAB). The experiments were performed with bacteria Asaia lannensis, a common spoilage in the beverage industry. The minimal inhibitory concentration (MIC) values were determined using the tube standard two-fold dilution method. The growth and adhesive properties of bacterial cells were studied in different culture media, and the cell viability was evaluated using plate count method. Both of the surfactants were effective against the bacterial strain, but the MIC of gemini compound was significantly lower. Both C6 and DTAB exhibited anti-adhesive abilities. Treatment with surfactants at or below MIC value decreased the number of bacterial cells that were able to form biofilm, however, the gemini surfactant was more effective. The used surfactants were also found to be able to eradicate mature biofilms. After 4 h of treatment with C6 surfactant at concentration 10 MIC, the number of bacterial cells was reduced by 91.8%. The results of this study suggest that the antibacterial activity of the gemini compound could make it an effective microbiocide against the spoilage bacteria Asaia sp. in both planktonic and biofilm stages.}, } @article {pmid29165147, year = {2017}, author = {Di Lodovico, S and Cataldi, V and Di Campli, E and Ancarani, E and Cellini, L and Di Giulio, M}, title = {Enterococcus hirae biofilm formation on hospital material surfaces and effect of new biocides.}, journal = {Environmental health and preventive medicine}, volume = {22}, number = {1}, pages = {63}, pmid = {29165147}, issn = {1347-4715}, support = {FAR ex 60 % 2015//Grant Prof. L. Cellini FAR ex 60 % 2015./ ; }, mesh = {Biofilms/*drug effects/growth & development ; Concanavalin A ; Cross Infection/microbiology/prevention & control ; Disinfectants/*pharmacology ; Enterococcus hirae/*drug effects/*physiology ; Equipment Contamination/prevention & control ; Equipment and Supplies, Hospital ; Humans ; Polystyrenes ; Stainless Steel ; }, abstract = {BACKGROUND: Nowadays, the bacterial contamination in the hospital environment is of particular concern because the hospital-acquired infections (HAIs), also known as nosocomial infections, are responsible for significant morbidity and mortality. This work evaluated the capability of Enterococcus hirae to form biofilm on different surfaces and the action of two biocides on the produced biofilms.

METHODS: The biofilm formation of E. hirae ATCC 10541 was studied on polystyrene and stainless steel surfaces through the biomass quantification and the cell viability at 20 and 37 °C. The effect of LH IDROXI FAST and LH ENZYCLEAN SPRAY biocides on biomasses was expressed as percentage of biofilm reduction. E. hirae at 20 and 37 °C produced more biofilm on the stainless steel in respect to the polystyrene surface. The amount of viable cells was greater at 20 °C than with 37 °C on the two analyzed surfaces. Biocides revealed a good anti-biofilm activity with the most effect for LH ENZYCLEAN SPRAY on polystyrene and stainless steel at 37 °C with a maximum biofilm reduction of 85.72 and 86.37%, respectively.

RESULTS: E. hirae is a moderate biofilm producer depending on surface material and temperature, and the analyzed biocides express a remarkable antibiofilm action.

CONCLUSION: The capability of E. hirae to form biofilm can be associated with its increasing incidence in hospital-acquired infections, and the adoption of suitable disinfectants is strongly recommended.}, } @article {pmid29164822, year = {2018}, author = {Okshevsky, M and Louw, MG and Lamela, EO and Nilsson, M and Tolker-Nielsen, T and Meyer, RL}, title = {A transposon mutant library of Bacillus cereus ATCC 10987 reveals novel genes required for biofilm formation and implicates motility as an important factor for pellicle-biofilm formation.}, journal = {MicrobiologyOpen}, volume = {7}, number = {2}, pages = {e00552}, pmid = {29164822}, issn = {2045-8827}, mesh = {Amino Acids/metabolism ; Bacillus cereus/*genetics/growth & development/physiology ; Biofilms/*growth & development ; Cell Division/genetics ; Chemotaxis/genetics ; DNA Transposable Elements/*genetics ; Extracellular Matrix/genetics ; Food Contamination ; Food Handling ; *Gene Library ; *Genomic Library ; Locomotion/*genetics ; }, abstract = {Bacillus cereus is one of the most common opportunistic pathogens causing foodborne illness, as well as a common source of contamination in the dairy industry. B. cereus can form robust biofilms on food processing surfaces, resulting in food contamination due to shedding of cells and spores. Despite the medical and industrial relevance of this species, the genetic basis of biofilm formation in B. cereus is not well studied. In order to identify genes required for biofilm formation in this bacterium, we created a library of 5000 + transposon mutants of the biofilm-forming strain B. cereusATCC 10987, using an unbiased mariner transposon approach. The mutant library was screened for the ability to form a pellicle biofilm at the air-media interface, as well as a submerged biofilm at the solid-media interface. A total of 91 genes were identified as essential for biofilm formation. These genes encode functions such as chemotaxis, amino acid metabolism and cellular repair mechanisms, and include numerous genes not previously known to be required for biofilm formation. Although the majority of disrupted genes are not directly responsible for motility, further investigations revealed that the vast majority of the biofilm-deficient mutants were also motility impaired. This observation implicates motility as a pivotal factor in the formation of a biofilm by B. cereus. These results expand our knowledge of the fundamental molecular mechanisms of biofilm formation by B. cereus.}, } @article {pmid29163441, year = {2017}, author = {Kumari, P and Mishra, R and Arora, N and Chatrath, A and Gangwar, R and Roy, P and Prasad, R}, title = {Antifungal and Anti-Biofilm Activity of Essential Oil Active Components against Cryptococcus neoformans and Cryptococcus laurentii.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2161}, pmid = {29163441}, issn = {1664-302X}, abstract = {Cryptococcosis is an emerging and recalcitrant systemic infection occurring in immunocompromised patients. This invasive fungal infection is difficult to treat due to the ability of Cryptococcus neoformans and Cryptococcus laurentii to form biofilms resistant to standard antifungal treatment. The toxicity concern of these drugs has stimulated the search for natural therapeutic alternatives. Essential oil and their active components (EO-ACs) have shown to possess the variety of biological and pharmacological properties. In the present investigation the effect of six (EO-ACs) sourced from Oregano oil (Carvacrol), Cinnamon oil (Cinnamaldehyde), Lemongrass oil (Citral), Clove oil (Eugenol), Peppermint oil (Menthol) and Thyme oil (thymol) against three infectious forms; planktonic cells, biofilm formation and preformed biofilm of C. neoformans and C. laurentii were evaluated as compared to standard drugs. Data showed that antibiofilm activity of the tested EO-ACs were in the order: thymol>carvacrol>citral>eugenol=cinnamaldehyde>menthol respectively. The three most potent EO-ACs, thymol, carvacrol, and citral showed excellent antibiofilm activity at a much lower concentration against C. laurentii in comparison to C. neoformans indicating the resistant nature of the latter. Effect of the potent EO-ACs on the biofilm morphology was visualized using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), which revealed the absence of extracellular polymeric matrix (EPM), reduction in cellular density and alteration in the surface morphology of biofilm cells. Further, to realize the efficacy of the EO-ACs in terms of human safety, cytotoxicity assays and co-culture model were evaluated. Thymol and carvacrol as compared to citral were the most efficient in terms of human safety in keratinocyte- Cryptococcus sp. co-culture infection model suggesting that these two can be further exploited as cost-effective and non-toxic anti-cryptococcal drugs.}, } @article {pmid29163440, year = {2017}, author = {Paytubi, S and Cansado, C and Madrid, C and Balsalobre, C}, title = {Nutrient Composition Promotes Switching between Pellicle and Bottom Biofilm in Salmonella.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2160}, pmid = {29163440}, issn = {1664-302X}, abstract = {Salmonella is one of the most frequently reported causes of foodborne illness worldwide. Non-typhoidal serovars cause gastroenteritis in humans. Salmonella can grow on surfaces forming biofilms, contributing to its persistence since biofilms are difficult to eradicate due to the high resistance to antimicrobials and disinfectants. It has been described that there are two crucial biofilm promoting factors in Salmonella: curli and cellulose. The expression of both factors is coordinately regulated by the transcriptional regulator CsgD. Most biofilm studies of Salmonella have been performed by growing bacteria in low osmolarity rich medium and low temperature (25°C). In such conditions, the biofilm is formed at the air-liquid interface (pellicle biofilm). Remarkably, when Salmonella grow in minimal medium, biofilm formation switches from the air-liquid interface to the solid-liquid interface (bottom biofilm). In this report, the switching between pellicle and bottom biofilm has been characterized. Our data indicate that curli, but not cellulose, is crucial for the formation of both kinds of biofilms. In minimal medium, conditions promoting formation of bottom biofilm, a high transcriptional expression of csgD and consequently of the genes involved in the synthesis of curli and cellulose was detected. The nutritional status of the cells seems to be pivotal for the spatial distribution of the biofilms formed. When bacteria is growing in minimal medium the addition of amino acids downregulates the expression of csgB and causes the switch between bottom and pellicle biofilm. The crosstalk between general metabolism and biofilm formation is also highlighted by the fact that the metabolic sensor cAMP modulates the type of biofilm generated by Salmonella. Moreover, cAMP regulates transcriptional expression of csgD and stimulates pellicle biofilm formation, suggesting that the physiological conditions define the type of biofilm formed by Salmonella. The consequences of the switching between pellicle and bottom biofilm during either infection or survival in natural environments remain undercover.}, } @article {pmid29163415, year = {2017}, author = {Yang, B and Lei, Z and Zhao, Y and Ahmed, S and Wang, C and Zhang, S and Fu, S and Cao, J and Qiu, Y}, title = {Combination Susceptibility Testing of Common Antimicrobials in Vitro and the Effects of Sub-MIC of Antimicrobials on Staphylococcus aureus Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2125}, pmid = {29163415}, issn = {1664-302X}, abstract = {The current study was conducted to evaluate the antibacterial combination efficacies, and whether the sub-inhibitory concentrations (sub-MIC) of antibiotics can influent on the biofilm formation of S. aureus. The minimum inhibitory concentration (MIC) of common antibacterial drugs was determined in vitro against clinical isolates of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pasteurella multocida (P. multocida) alone and in combination with each other by using the broth microdilution method and the checkerboard micro-dilution method analyzed with the fractional inhibitory concentration index (FICI), respectively. Regarding these results, antibacterial drug combinations were categorized as synergistic, interacting, antagonistic and indifferent, and most of the results were consistent with the previous reports. Additionally, the effects of sub-MIC of seven antimicrobials (kanamycin, acetylisovaleryltylosin tartrate, enrofloxacin, lincomycin, colistin sulfate, berberine, and clarithromycin) on S. aureus biofilm formation were determined via crystal violet staining, scanning electron microscopy (SEM) and real-time PCR. Our results demonstrate that all antibiotics, except acetylisovaleryltylosin tartrate, effectively reduced the S. aureus biofilm formation. In addition, real-time reverse transcriptase PCR was used to analyze the relative expression levels of S. aureus biofilm-related genes such as sarA, fnbA, rbf, lrgA, cidA, and eno after the treatment at sub-MIC with all of the six antimicrobials. All antibiotics significantly inhibited the expression of these biofilm-related genes except for acetylisovaleryltylosin tartrate, which efficiently up-regulated these transcripts. These results provide the theoretical parameters for the selection of effective antimicrobial combinations in clinical therapy and demonstrate how to correctly use antibiotics at sub-MIC as preventive drugs.}, } @article {pmid29163410, year = {2017}, author = {Balsa-Canto, E and Vilas, C and López-Núñez, A and Mosquera-Fernández, M and Briandet, R and Cabo, ML and Vázquez, C}, title = {Modeling Reveals the Role of Aging and Glucose Uptake Impairment in L1A1 Listeria monocytogenes Biofilm Life Cycle.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2118}, pmid = {29163410}, issn = {1664-302X}, abstract = {Listeria monocytogenes is a food-borne pathogen that can persist in food processing plants by forming biofilms on abiotic surfaces. The benefits that bacteria can gain from living in a biofilm, i.e., protection from environmental factors and tolerance to biocides, have been linked to the biofilm structure. Different L. monocytogenes strains build biofilms with diverse structures, and the underlying mechanisms for that diversity are not yet fully known. This work combines quantitative image analysis, cell counts, nutrient uptake data and mathematical modeling to provide a mechanistic insight into the dynamics of the structure of biofilms formed by L. monocytogenes L1A1 (serotype 1/2a) strain. Confocal laser scanning microscopy (CLSM) and quantitative image analysis were used to characterize the structure of L1A1 biofilms throughout time. L1A1 forms flat, thick structures; damaged or dead cells start appearing early in deep layers of the biofilm and rapidly and massively loss biomass after 4 days. We proposed several reaction-diffusion models to explain the system dynamics. Model candidates describe biomass and nutrients evolution including mechanisms of growth and cell spreading, nutrients diffusion and uptake and biofilm decay. Data fitting was used to estimate unknown model parameters and to choose the most appropriate candidate model. Remarkably, standard reaction-diffusion models could not describe the biofilm dynamics. The selected model reveals that biofilm aging and glucose impaired uptake play a critical role in L1A1 L. monocytogenes biofilm life cycle.}, } @article {pmid29163392, year = {2017}, author = {Li, W and Li, Y and Liu, Y and Shi, X and Jiang, M and Lin, Y and Qiu, Y and Zhang, Q and Chen, Q and Zhou, L and Sun, Q and Hu, Q}, title = {Clonal Expansion of Biofilm-Forming Salmonella Typhimurium ST34 with Multidrug-Resistance Phenotype in the Southern Coastal Region of China.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2090}, pmid = {29163392}, issn = {1664-302X}, abstract = {To disclose the antibiotics susceptibility and wide adaptability of commonly occurring genotypes of Salmonella Typhimurium, the antibiotic resistance and biofilm formation of different multi-locus sequence typing (MLST) types of a collection of 240 S. Typhimurium isolates (33 food and 207 clinical ones) during 2010-2014 in Shenzhen were analyzed. Among these strains, 167 was ST34 (69.58%), and 57 was ST19 (23.75%), respectively. A total of 159 (95.21%) ST34 strains displayed the multidrug resistant phenotype (≥ three classes of antibiotic), whereas only 23 (40.35%) ST19 ones did (P < 0.01). Moreover, a relative high proportion (72.46%) of ST34 isolates was classified as moderate to strong biofilm-producers, while only 15.79% of ST19 (P < 0.01) was. Among the food isolates, more than half (51.52%) were from livestock products, among which 41.18% classified as moderate to strong biofilm-producers. In summary, this study highlights the expansion of S. Typhimurium ST34 of strong biofilm-forming ability and multidrug resistance in the southern coastal region of China. Therefore, monitoring the occurrence of ST34 S. Typhimurium in food sources, especially in livestock products, and taking appropriate measures to control Salmonella spp. infections via decreasing biofilm formation should be addressed.}, } @article {pmid29163384, year = {2017}, author = {Gingichashvili, S and Duanis-Assaf, D and Shemesh, M and Featherstone, JDB and Feuerstein, O and Steinberg, D}, title = {Bacillus subtilis Biofilm Development - A Computerized Study of Morphology and Kinetics.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2072}, pmid = {29163384}, issn = {1664-302X}, abstract = {Biofilm is commonly defined as accumulation of microbes, embedded in a self-secreted extra-cellular matrix, on solid surfaces or liquid interfaces. In this study, we analyze several aspects of Bacillus subtilis biofilm formation using tools from the field of image processing. Specifically, we characterize the growth kinetics and morphological features of B. subtilis colony type biofilm formation and compare these in colonies grown on two different types of solid media. Additionally, we propose a model for assessing B. subtilis biofilm complexity across different growth conditions. GFP-labeled B. subtilis cells were cultured on agar surfaces over a 4-day period during which microscopic images of developing colonies were taken at equal time intervals. The images were used to perform a computerized analysis of few aspects of biofilm development, based on features that characterize the different phenotypes of B. subtilis colonies. Specifically, the analysis focused on the segmented structure of the colonies, consisting of two different regions of sub-populations that comprise the biofilm - a central "core" region and an "expanding" region surrounding it. Our results demonstrate that complex biofilm of B. subtillis grown on biofilm-promoting medium [standard lysogeny broth (LB) supplemented with manganese and glycerol] is characterized by rapidly developing three-dimensional complex structure observed at its core compared to biofilm grown on standard LB. As the biofilm develops, the core size remains largely unchanged during development and colony expansion is mostly attributed to the expansion in area of outer cell sub-populations. Moreover, when comparing the bacterial growth on biofilm-promoting agar to that of colonies grown on LB, we found a significant decrease in the GFP production of colonies that formed a more complex biofilm. This suggests that complex biofilm formation has a diminishing effect on cell populations at the biofilm core, likely due to a combination of reduced metabolic rate and increased levels of cell death within this region.}, } @article {pmid29163197, year = {2017}, author = {Pang, L and Zhi, Q and Zhuang, P and Yu, L and Tao, Y and Lin, H}, title = {Variation in Enamel Formation Genes Influences Enamel Demineralization In Vitro in a Streptococcus mutans Biofilm Model.}, journal = {Frontiers in physiology}, volume = {8}, number = {}, pages = {851}, pmid = {29163197}, issn = {1664-042X}, abstract = {Genetic studies have shown that variations in enamel formation genes are associated with caries susceptibility. The aim of this study was to test in vitro whether variants in these genes are associated with dental enamel demineralization in a Streptococcus mutans biofilm model. DNA and enamel samples were obtained from 213 individuals. DNA was extracted from saliva, and 16 single nucleotide polymorphisms were analyzed. The physical and chemical properties of sound enamel samples and the mineral loss and the lesion depth of the demineralized enamel samples under cariogenic challenge were analyzed. Microhardness, enamel chemicals, mineral loss and demineralization depth were compared between different genotypes at each single nucleotide polymorphism. The GG genotype of TUFT1 (rs17640579) and the GT genotype of MMP20 (rs1612069) exhibited increased microhardness (p = 0.044 and 0.016, respectively). The GG genotype of AMBN (rs7694409) had a higher magnesium level, while the CT genotype of TFIP11 (rs2097470) had a lower magnesium level (p = 0.044 and 0.046, respectively). The GT genotype of MMP20 (rs1612069) had a higher calcium level (p = 0.034). The GG genotype of AMBN (rs13115627), the AG genotype of ENAM (rs12640848) and the AA genotype of MMP20 (rs2292730) had a lower phosphorus level (p = 0.012, 0.006, and 0.023, respectively). The GG genotype of AMBN (rs13115627) was also associated with a higher calcium-phosphorus ratio (p = 0.034). Individuals with the CC genotype of TFIP11 (rs134143) exhibited significantly more mineral loss (p = 0.011) and a deeper lesions (p = 0.042). Individuals with the TT genotype of TFIP11 (rs2097470) had more mineral loss (p = 0.018). Individuals with the GG genotype of TUFT1 (rs17640579) exhibited a shallower demineralization depth (p = 0.047). Individuals with the GT genotype of MMP20 (rs1612069) exhibited a shallower demineralization depth (p = 0.042). Individuals with the GG genotype of ENAM (rs12640848) exhibited less mineral loss (p = 0.01) and a shallower demineralization depth (p = 0.03). Genetic variations in TFIP11, TUFT1, MMP20, and ENAM influenced enamel demineralization in a Streptococcus mutans biofilm model.}, } @article {pmid29162873, year = {2017}, author = {Ogrodzki, P and Cheung, CS and Saad, M and Dahmani, K and Coxill, R and Liang, H and Forsythe, SJ}, title = {Rapid in situ imaging and whole genome sequencing of biofilm in neonatal feeding tubes: A clinical proof of concept.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {15948}, pmid = {29162873}, issn = {2045-2322}, mesh = {*Biofilms ; *Enteral Nutrition ; Enterobacter/genetics/isolation & purification ; Enterococcus faecalis/genetics/physiology ; Genome, Bacterial ; Humans ; *Imaging, Three-Dimensional ; Infant, Newborn ; Male ; Phylogeny ; Polymorphism, Single Nucleotide/genetics ; Tomography, Optical Coherence ; *Whole Genome Sequencing ; }, abstract = {The bacterial flora of nasogastric feeding tubes and faecal samples were analysed for a low-birth weight (725 g) neonate EGA 25 weeks in intensive care. Samples were collected at age 6 and 8 weeks of life. Optical coherence tomography (OCT) was used to visualise bacterial biofilms inside the nasogastric feeding tubes. The biofilm was heterogeneously distributed along the tube lumen wall, and had a depth of up to 500 µm. The bacterial biofilm and faecal samples included Enterococcus faecalis and Enterobacter hormaechei. Representative strains, recovered from both feeding tubes and faecal samples, were whole genome sequenced using Illumina, Mi-Seq, which revealed indistinguishable strains, each with less than 28 SNP differences, of E. faecalis and E. hormaechei. The E. faecalis strains were from two sequence types (ST191 and ST211) and encoded for a number of traits related to biofilm formation (BopD), adherence (Epb pili), virulence (cps loci, gelatinase, SprE) and antibiotic resistances (IsaA, tetM). The E. hormaechei were all ST106, and encoded for blaACT-15 β-lactamase and fosfomycin resistance (fosA). This proof of concept study demonstrates that bacterial flora within the neonatal feeding tubes may influence the bacterial colonisation of the intestinal tract and can be visualised non-destructively using OCT.}, } @article {pmid29162713, year = {2017}, author = {Petruzzi, B and Briggs, RE and Tatum, FM and Swords, WE and De Castro, C and Molinaro, A and Inzana, TJ}, title = {Capsular Polysaccharide Interferes with Biofilm Formation by Pasteurella multocida Serogroup A.}, journal = {mBio}, volume = {8}, number = {6}, pages = {}, pmid = {29162713}, issn = {2150-7511}, mesh = {Bacterial Capsules/*chemistry/genetics/*metabolism ; *Biofilms ; Glycogen/metabolism ; Humans ; Hyaluronoglucosaminidase/pharmacology ; Mutation ; Pasteurella Infections/microbiology ; Pasteurella multocida/drug effects/genetics/*metabolism/pathogenicity ; Polysaccharides/genetics/*metabolism ; Serogroup ; Virulence Factors ; }, abstract = {Pasteurella multocida is an important multihost animal and zoonotic pathogen that is capable of causing respiratory and multisystemic diseases, bacteremia, and bite wound infections. The glycosaminoglycan capsule of P. multocida is an essential virulence factor that protects the bacterium from host defenses. However, chronic infections (such as swine atrophic rhinitis and the carrier state in birds and other animals) may be associated with biofilm formation, which has not been characterized in P. multocida Biofilm formation by clinical isolates was inversely related to capsule production and was confirmed with capsule-deficient mutants of highly encapsulated strains. Capsule-deficient mutants formed biofilms with a larger biomass that was thicker and smoother than the biofilm of encapsulated strains. Passage of a highly encapsulated, poor-biofilm-forming strain under conditions that favored biofilm formation resulted in the production of less capsular polysaccharide and a more robust biofilm, as did addition of hyaluronidase to the growth medium of all of the strains tested. The matrix material of the biofilm was composed predominately of a glycogen exopolysaccharide (EPS), as determined by gas chromatography-mass spectrometry, nuclear magnetic resonance, and enzymatic digestion. However, a putative glycogen synthesis locus was not differentially regulated when the bacteria were grown as a biofilm or planktonically, as determined by quantitative reverse transcriptase PCR. Therefore, the negatively charged capsule may interfere with biofilm formation by blocking adherence to a surface or by preventing the EPS matrix from encasing large numbers of bacterial cells. This is the first detailed description of biofilm formation and a glycogen EPS by P. multocidaIMPORTANCEPasteurella multocida is an important pathogen responsible for severe infections in food animals, domestic and wild birds, pet animals, and humans. P. multocida was first isolated by Louis Pasteur in 1880 and has been studied for over 130 years. However, aspects of its lifecycle have remained unknown. Although formation of a biofilm by P. multocida has been proposed, this report is the first to characterize biofilm formation by P. multocida Of particular interest is that the biofilm matrix material contained a newly reported amylose-like glycogen as the exopolysaccharide component and that production of capsular polysaccharide (CPS) was inversely related to biofilm formation. However, even highly mucoid, poor-biofilm-forming strains could form abundant biofilms by loss of CPS or following in vitro passage under biofilm growth conditions. Therefore, the carrier state or subclinical chronic infections with P. multocida may result from CPS downregulation with concomitant enhanced biofilm formation.}, } @article {pmid29162482, year = {2017}, author = {de Souza, ME and Clerici, DJ and Verdi, CM and Fleck, G and Quatrin, PM and Spat, LE and Bonez, PC and Santos, CFD and Antoniazzi, RP and Zanatta, FB and Gundel, A and Martinez, DST and de Almeida Vaucher, R and Santos, RCV}, title = {Antimicrobial activity of Melaleuca alternifolia nanoparticles in polymicrobial biofilm in situ.}, journal = {Microbial pathogenesis}, volume = {113}, number = {}, pages = {432-437}, doi = {10.1016/j.micpath.2017.11.005}, pmid = {29162482}, issn = {1096-1208}, mesh = {Adult ; Animals ; Anti-Infective Agents/*pharmacology ; Bacteria/drug effects ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Brazil ; Cattle ; Chlorhexidine/pharmacology ; Colony Count, Microbial ; Dental Enamel/microbiology ; Dental Plaque/drug therapy/microbiology/prevention & control ; Female ; Humans ; Hydrogen-Ion Concentration ; Male ; Melaleuca/*chemistry ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Nanoparticles/*chemistry ; Particle Size ; Pilot Projects ; Plant Exudates/*pharmacology ; Sodium Chloride/pharmacology ; Tea Tree Oil/pharmacology ; Time Factors ; Young Adult ; }, abstract = {Microbial biofilms represent a challenge in the treatment of infections, due to the low efficacy of the antimicrobials. This study evaluated the antimicrobial effect of nanoparticles of Melaleuca alternifolia (TTO) in dental biofilm. Thirty-eight volunteers used an oral device in situ in situ including four bovine enamel specimens for 07 days. From the fifth day four solutions were applied randomly for each specimen: Physiological Saline Solution (0.85% NaCl) (C+), Chlorhexidine 0.12% (CHX), M. alternifolia oil 0.3% (TTO), and a nanoparticle solution of 0.3% M. alternifolia oil (NPTTO). The nanoparticles of TTO were characterized for pH, IPD, medium size, zeta potential and Transmission Electron Microscopy. Antimicrobial activity was evaluated by viable microorganisms count and the structure of the biofilm by atomic force microscopy. The NPTTO presented pH 6.4, particle diameter of 197.9 ± 1 nm, polydispersion index of 0.242 ± 0.005, zeta potential of -7.12 mV and ±0:27 spherical shape. The C+ resulted in 100% of bacterial vitality, while CHX, TTO and NPTTO showed 34.2%, 51.4% and 25.8%, respectively. The AFM images showed biofilms with an average roughness of 350 nm for C+, 275 nm for CHX, 500 nm for TTO and 100 nm for NPTTO. The NPTTO demonstrated excellent antimicrobial activity in the biofilm formed in situ and will possibly be used in future for the treatment/prevention of oral biofilms.}, } @article {pmid29160874, year = {2017}, author = {Sadrearhami, Z and Yeow, J and Nguyen, TK and Ho, KKK and Kumar, N and Boyer, C}, title = {Biofilm dispersal using nitric oxide loaded nanoparticles fabricated by photo-PISA: influence of morphology.}, journal = {Chemical communications (Cambridge, England)}, volume = {53}, number = {96}, pages = {12894-12897}, doi = {10.1039/c7cc07293g}, pmid = {29160874}, issn = {1364-548X}, abstract = {Polymeric nanoparticles (NPs) of different morphologies (spheres and worms) were synthesized using a visible light mediated polymerization-induced self-assembly (PISA) approach. Spherical and worm-like NPs were subsequently modified to generate diazeniumdiolate functionalized NPs. Interestingly, the NO release rate and the dispersal of biofilms were found to strongly depend on the NP morphology. NPs with a higher aspect ratio (worms) exhibited a slower NO release rate and greater biofilm dispersal after 1 h of incubation.}, } @article {pmid29160391, year = {2017}, author = {Freire, PLL and Albuquerque, AJR and Sampaio, FC and Galembeck, A and Flores, MAP and Stamford, TCM and Rosenblatt, A}, title = {AgNPs: The New Allies Against S. Mutans Biofilm - A Pilot Clinical Trial and Microbiological Assay.}, journal = {Brazilian dental journal}, volume = {28}, number = {4}, pages = {417-422}, doi = {10.1590/0103-6440201600994}, pmid = {29160391}, issn = {1806-4760}, mesh = {*Biofilms ; Child ; Colony Count, Microbial ; Cross-Over Studies ; Double-Blind Method ; Female ; Humans ; Hydrogen-Ion Concentration ; Male ; *Metal Nanoparticles/chemistry ; Oral Hygiene Index ; Pilot Projects ; Prospective Studies ; Silver/*chemistry ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {The purpose of this study was to evaluate the antimicrobial properties of a new formulation containing silver nanoparticles, named Nano Silver Fluoride (NSF), to inhibit Streptococcus mutans biofilm formation on children's dental enamel. The variations in dental biofilm pH and in the Simplified-Oral-Hygiene-Index (OHI-S) also were evaluated after the treatment with NSF. This was a randomized, double-blind, crossover and prospective pilot clinical trial study in which 12 schoolchildren, aged between 7-8 years, had their dental enamel treated with two solutions: S1 - Nano Silver Fluoride and S2 - negative control (saline solution), in different experimental moments. The dental biofilm adhered to enamel treated with NSF had lower values of S. mutans viability (absorbance) and colony forming units (CFU) than the S0 (baseline) and S2. There was a statistically significant difference between the OHI-S mean values of S0 and S1. There were no differences between the biofilm pH (both before and after the use of the test substances) and among the different groups. These properties suggest that NSF has bactericidal effect against S. mutans biofilm and it may be used for clinical control and prevention of dental biofilm formation.}, } @article {pmid29160206, year = {2017}, author = {Jo, J and Cortez, KL and Cornell, WC and Price-Whelan, A and Dietrich, LE}, title = {An orphan cbb3-type cytochrome oxidase subunit supports Pseudomonas aeruginosa biofilm growth and virulence.}, journal = {eLife}, volume = {6}, number = {}, pages = {}, pmid = {29160206}, issn = {2050-084X}, support = {R01 AI103369/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Caenorhabditis elegans/microbiology ; Disease Models, Animal ; Electron Transport Complex IV/genetics/*metabolism ; Pseudomonas Infections/*microbiology/*pathology ; Pseudomonas aeruginosa/*pathogenicity/*physiology ; Virulence ; }, abstract = {Hypoxia is a common challenge faced by bacteria during associations with hosts due in part to the formation of densely packed communities (biofilms). cbb3-type cytochrome c oxidases, which catalyze the terminal step in respiration and have a high affinity for oxygen, have been linked to bacterial pathogenesis. The pseudomonads are unusual in that they often contain multiple full and partial (i.e. 'orphan') operons for cbb3-type oxidases and oxidase subunits. Here, we describe a unique role for the orphan catalytic subunit CcoN4 in colony biofilm development and respiration in the opportunistic pathogen Pseudomonas aeruginosa PA14. We also show that CcoN4 contributes to the reduction of phenazines, antibiotics that support redox balancing for cells in biofilms, and to virulence in a Caenorhabditis elegans model of infection. These results highlight the relevance of the colony biofilm model to pathogenicity and underscore the potential of cbb3-type oxidases as therapeutic targets.}, } @article {pmid29160100, year = {2017}, author = {Yoon, HY and Lee, SY}, title = {Establishing a laboratory model of dental unit waterlines bacterial biofilms using a CDC biofilm reactor.}, journal = {Biofouling}, volume = {33}, number = {10}, pages = {917-926}, doi = {10.1080/08927014.2017.1391950}, pmid = {29160100}, issn = {1029-2454}, mesh = {Bacteria/drug effects/growth & development ; Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bioreactors ; Centers for Disease Control and Prevention, U.S. ; Colony Count, Microbial ; Dental Equipment/*microbiology ; Disinfection/methods ; *Equipment Contamination ; Polyurethanes ; Reproducibility of Results ; United States ; Water Microbiology ; }, abstract = {In this study, a laboratory model to reproduce dental unit waterline (DUWL) biofilms was developed using a CDC biofilm reactor (CBR). Bacteria obtained from DUWLs were filtered and cultured in Reasoner's 2A (R2A) for 10 days, and were subsequently stored at -70°C. This stock was cultivated on R2A in batch mode. After culturing for five days, the bacteria were inoculated into the CBR. Biofilms were grown on polyurethane tubing for four days. Biofilm accumulation and thickness was 1.3 × 10[5] CFU cm[-2] and 10-14 μm respectively, after four days. Bacteria in the biofilms included cocci and rods of short and medium lengths. In addition, 38 bacterial genera were detected in biofilms. In this study, the suitability and reproducibility of the CBR model for DUWL biofilm formation were demonstrated. The model provides a foundation for the development of bacterial control methods for DUWLs.}, } @article {pmid29159172, year = {2017}, author = {MacKenzie, KD and Palmer, MB and Köster, WL and White, AP}, title = {Examining the Link between Biofilm Formation and the Ability of Pathogenic Salmonella Strains to Colonize Multiple Host Species.}, journal = {Frontiers in veterinary science}, volume = {4}, number = {}, pages = {138}, pmid = {29159172}, issn = {2297-1769}, abstract = {Salmonella are important pathogens worldwide and a predominant number of human infections are zoonotic in nature. The ability of strains to form biofilms, which is a multicellular behavior characterized by the aggregation of cells, is predicted to be a conserved strategy for increased persistence and survival. It may also contribute to the increasing number of infections caused by ingestion of contaminated fruits and vegetables. There is a correlation between biofilm formation and the ability of strains to colonize and replicate within the intestines of multiple host species. These strains predominantly cause localized gastroenteritis infections in humans. In contrast, there are salmonellae that cause systemic, disseminated infections in a select few host species; these "invasive" strains have a narrowed host range, and most are unable to form biofilms. This includes host-restricted Salmonella serovar Typhi, which are only able to infect humans, and atypical gastroenteritis strains associated with the opportunistic infection of immunocompromised patients. From the perspective of transmission, biofilm formation is advantageous for ensuring pathogen survival in the environment. However, from an infection point of view, biofilm formation may be an anti-virulence trait. We do not know if the capacity to form biofilms prevents a strain from accessing the systemic compartments within the host or if loss of the biofilm phenotype reflects a change in a strain's interaction with the host. In this review, we examine the connections between biofilm formation, Salmonella disease states, degrees of host adaptation, and how this might relate to different transmission patterns. A better understanding of the dynamic lifecycle of Salmonella will allow us to reduce the burden of livestock and human infections caused by these important pathogens.}, } @article {pmid29157962, year = {2018}, author = {Fernandes, T and Bhavsar, C and Sawarkar, S and D'souza, A}, title = {Current and novel approaches for control of dental biofilm.}, journal = {International journal of pharmaceutics}, volume = {536}, number = {1}, pages = {199-210}, doi = {10.1016/j.ijpharm.2017.11.019}, pmid = {29157962}, issn = {1873-3476}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects ; Drug Delivery Systems/methods ; Humans ; Mouth/*microbiology ; Nanoparticles/administration & dosage ; Tooth/*microbiology ; }, abstract = {Insights in oral demographics have revealed that a significant percentage of population faces chronic incidences of oral diseases. The innervation of these oral manifestations is required because untreated conditions may lead to bone loss in the oral cavity and systemic complications. Conventional treatments include surgery of the affected area followed by its management and/or treatment with antibiotics. However, widely used antibiotics like Triclosan have serious side effects including down-regulation of oral keratinocytes and fibroblasts. Thus, novel treatments with more targeted approaches have been under investigation. Treatment modalities like Viral mediated gene delivery, liposomes, nanoparticles, and nanobubbles not only help in management of oral diseases but also aid in reducing the biofilm formed due to bacterial bioburden in the areas less accessible through oral and conventional means. This review focuses on the limitation of conventional treatments and highlights the recent investigations in the use of the novel treatment approaches in order to increase the patient compliance and alleviation of side effects. The authors have also tried to emphasize on the future perspectives of glucansucrase inhibitors, photodynamic therapy and probiotics as targeted drug delivery systems. However, further investigations are necessary for implementation of these novel approaches in the clinical setup.}, } @article {pmid29156876, year = {2017}, author = {Köse, H and Yapar, N}, title = {The comparison of various disinfectants? efficacy on Staphylococcus aureus and Pseudomonas aeruginosa biofilm layers.}, journal = {Turkish journal of medical sciences}, volume = {47}, number = {4}, pages = {1287-1294}, doi = {10.3906/sag-1605-88}, pmid = {29156876}, issn = {1303-6165}, abstract = {Background/aim: Because biofilms are resistant to antibiotics and biocides, they usually cause chronic persistent infections, which are arduous to cure and have high mortality and morbidity. Our study aimed to investigate the efficiency of orthophthalaldehyde, peracetic acid, hydrogen peroxide, and sodium hypochlorite on Pseudomonas aeruginosa and Staphylococcus aureus biofilm layers and live microbial cells. Materials and methods: Biofilm layers were determined by crystal violet assay and live microbial cells were determined using a resazurin assay. Results: For Pseudomonas aeruginosa, sodium hypochlorite showed the most influential disinfection because it diminished 83.6% of the biofilm layer and decreased 99.7% of live microbial cells. For Staphylococcus aureus, hydrogen peroxide was determined the most active disinfectant with 80.3% reduction of the biofilm layer. Sodium hypochlorite was also determined to be the most efficient disinfectant with 99.8% reduction of live microbial cells. Sodium hypochlorite was the most influential disinfectant on biofilm layers and live microbial cells of both microorganisms. Conclusion: We concluded that if we use sodium hypochlorite at a high level as a disinfectant for both surfaces and medical equipment, it is beneficial to prevent infections related to biofilms. More studies about prevention of biofilm occurrence and standardization of the methods for investigating disinfectants? effects are necessary.}, } @article {pmid29156005, year = {2018}, author = {Rajput, A and Thakur, A and Sharma, S and Kumar, M}, title = {aBiofilm: a resource of anti-biofilm agents and their potential implications in targeting antibiotic drug resistance.}, journal = {Nucleic acids research}, volume = {46}, number = {D1}, pages = {D894-D900}, pmid = {29156005}, issn = {1362-4962}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; *Anti-Infective Agents/pharmacology/therapeutic use ; Antifungal Agents/pharmacology/therapeutic use ; Bacteria/drug effects ; Biofilms/*drug effects ; Data Curation ; Data Display ; *Databases, Chemical ; Drug Delivery Systems ; *Drug Discovery ; *Drug Resistance, Microbial ; Fungi/drug effects ; Information Storage and Retrieval ; Microbiota/drug effects ; Quantitative Structure-Activity Relationship ; Quorum Sensing ; }, abstract = {Biofilms play an important role in the antibiotic drug resistance, which is threatening public health globally. Almost, all microbes mimic multicellular lifestyle to form biofilm by undergoing phenotypic changes to adapt adverse environmental conditions. Many anti-biofilm agents have been experimentally validated to disrupt the biofilms during last three decades. To organize this data, we developed the 'aBiofilm' resource (http://bioinfo.imtech.res.in/manojk/abiofilm/) that harbors a database, a predictor, and the data visualization modules. The database contains biological, chemical, and structural details of 5027 anti-biofilm agents (1720 unique) reported from 1988-2017. These agents target over 140 organisms including Gram-negative, Gram-positive bacteria, and fungus. They are mainly chemicals, peptides, phages, secondary metabolites, antibodies, nanoparticles and extracts. They show the diverse mode of actions by attacking mainly signaling molecules, biofilm matrix, genes, extracellular polymeric substances, and many more. The QSAR based predictor identifies the anti-biofilm potential of an unknown chemical with an accuracy of ∼80.00%. The data visualization section summarized the biofilm stages targeted (Circos plot); interaction maps (Cytoscape) and chemicals diversification (CheS-Mapper) of the agents. This comprehensive platform would help the researchers to understand the multilevel communication in the microbial consortium. It may aid in developing anti-biofilm therapeutics to deal with antibiotic drug resistance menace.}, } @article {pmid29153513, year = {2018}, author = {Thiran, E and Di Ciccio, PA and Graber, HU and Zanardi, E and Ianieri, A and Hummerjohann, J}, title = {Biofilm formation of Staphylococcus aureus dairy isolates representing different genotypes.}, journal = {Journal of dairy science}, volume = {101}, number = {2}, pages = {1000-1012}, doi = {10.3168/jds.2017-13696}, pmid = {29153513}, issn = {1525-3198}, mesh = {Animals ; *Biofilms/growth & development ; Cattle ; Cheese/*microbiology ; Genotype ; Goats ; Italy ; Methicillin-Resistant Staphylococcus aureus/classification/genetics/isolation & purification/physiology ; Milk/*microbiology ; Polymerase Chain Reaction ; Sheep ; Staphylococcus aureus/classification/genetics/isolation & purification/*physiology ; Switzerland ; }, abstract = {The objective of this study was to compare the biofilm-forming capabilities of different genotypes of Staphylococcus aureus dairy isolates from Switzerland and northern Italy, including Staph. aureus genotype B (GTB) and methicillin-resistant Staph.aureus (MRSA). We hypothesized that biofilm formation might be more pronounced in the contagious GTB isolates compared with other genotypes affecting individual animals. Twenty-four dairy isolates, including 9 MRSA, were further characterized by genotyping by using ribosomal spacer PCR, spa typing, biofilm formation under static and dynamic conditions, and scanning electron microscopy. The GTB isolates (n = 6) were more able to form biofilms than other genotypes at 37°C and at 20°C after 48 and 72 h of incubation in the static assay using polystyrene microtiter plates. This result was supported by scanning electron micrographs showing a GTB isolate producing strong biofilm with extracellular matrix in contrast to a genotype C isolate. Furthermore, none of the MRSA isolates formed strong biofilms in the static assay. However, some MRSA produced low or moderate amounts of biofilm depending on the applied conditions. Under dynamic conditions, a much more diverse situation was observed. The ability of GTB isolates to be strong biofilm formers was not observed in all cases, emphasizing the importance of growth conditions for the expression of biofilm-related genes. No specific genotype, spa type, or MRSA isolate could be categorized significantly into one level of biofilm formation. Nineteen percent of isolates behaved similarly under static and dynamic conditions. The results of this study expand our knowledge of different dairy-related Staph. aureus subtypes and indicate the benefit of genotyping when biofilms are studied.}, } @article {pmid29152581, year = {2017}, author = {Flanagan, PR and Liu, NN and Fitzpatrick, DJ and Hokamp, K and Köhler, JR and Moran, GP}, title = {The Candida albicans TOR-Activating GTPases Gtr1 and Rhb1 Coregulate Starvation Responses and Biofilm Formation.}, journal = {mSphere}, volume = {2}, number = {6}, pages = {}, pmid = {29152581}, issn = {2379-5042}, support = {R01 AI095305/AI/NIAID NIH HHS/United States ; R21 AI096054/AI/NIAID NIH HHS/United States ; }, abstract = {Target of rapamycin complex 1 (TORC1) is an essential regulator of metabolism in eukaryotic cells and in the fungal pathogen Candida albicans regulates morphogenesis and nitrogen acquisition. Gtr1 encodes a highly conserved GTPase that in Saccharomyces cerevisiae regulates nitrogen sensing and TORC1 activation. Here, we characterize the role of C. albicans GTR1 in TORC1 activation and compare it with the previously characterized GTPase Rhb1. A homozygous gtr1/gtr1 mutant exhibited impaired TORC1-mediated phosphorylation of ribosomal protein S6 and increased susceptibility to rapamycin. Overexpression of GTR1 impaired nitrogen starvation-induced filamentous growth, MEP2 expression, and growth in bovine serum albumin as the sole nitrogen source. Both GTR1 and RHB1 were shown to regulate genes involved in ribosome biogenesis, amino acid biosynthesis, and expression of biofilm growth-induced genes. The rhb1/rhb1 mutant exhibited a different pattern of expression of Sko1-regulated genes and increased susceptibility to Congo red and calcofluor white. The homozygous gtr1/gtr1 mutant exhibited enhanced flocculation phenotypes and, similar to the rhb1/rhb1 mutant, exhibited enhanced biofilm formation on plastic surfaces. In summary, Gtr1 and Rhb1 link nutrient sensing and biofilm formation and this connectivity may have evolved to enhance the competitiveness of C. albicans in niches where there is intense competition with other microbes for space and nutrients. IMPORTANCECandida albicans is the major fungal pathogen of humans and is responsible for a wide range of infections, including life-threatening systemic infections in susceptible hosts. Target of rapamycin complex 1 (TORC1) is an essential regulator of metabolism in this fungus, and components of this complex are under increased investigation as targets for new antifungal drugs. The present study characterized the role of GTR1, encoding a putative GTPase, in TORC1 activation. This study shows that GTR1 encodes a protein required for activation of TORC1 activity in response to amino acids and regulation of nitrogen starvation responses. GTR1 mutants show increased cell-cell adhesion and biofilm formation and increased expression of genes involved in these processes. This study demonstrates that starvation responses and biofilm formation are coregulated by GTR1 and suggests that these responses are linked to compete with the microbiome for space and nutrients.}, } @article {pmid29151896, year = {2017}, author = {Zhang, T and Dong, J and Cheng, Y and Lu, Q and Luo, Q and Wen, G and Liu, G and Shao, H}, title = {Genotypic diversity, antimicrobial resistance and biofilm-forming abilities of Campylobacter isolated from chicken in Central China.}, journal = {Gut pathogens}, volume = {9}, number = {}, pages = {62}, pmid = {29151896}, issn = {1757-4749}, abstract = {BACKGROUND: Campylobacter is considered to be the leading cause of human bacterial gastroenteritis, of which poultry is the main reservoir. Campylobacter contaminated chicken products are a major cause of human Campylobacter infection. In this study, the prevalence of Campylobacter in chicken in central China was investigated, and the genotypic diversity, antimicrobial resistance and biofilm of these isolates were characterized.

RESULTS: A total of 206 Campylobacter isolates, including 166 C. jejuni and 40 C. coli, were isolated from chicken farms and live poultry markets in central China. Multilocus sequence typing and phylogenetic analysis showed that the Campylobacter isolates had diverse genetic backgrounds, which covered most of the dominant clone complexes (CCs) reported throughout China. The most prevalent CCs were CC-464, CC-1150, CC-353, and CC-828. All the isolates showed resistance to norfloxacin, ciprofloxacin and Cefazolin, and a prevalent resistance to fluoroquinolones, β-lactams and tetracyclines was also observed. Among all the isolates, 133 strains showed the ability to form biofilm, thereinto, the isolates in two genetic branches, mainly including CC-21, CC-48, CC-677 and CC-45, showed a significantly lower ability to form biofilm than other genetic branches (p < 0.05). However, in general, the ability to form biofilm varied among different genetic branches, suggesting a complex genetic background to biofilm formation, but not only the genetic lineages. Compared with the strains unable to form biofilm, biofilm-producing strains possessed a significantly higher resistance to ampicillin, neomycin, sulfamethoxazole, amikacin, clindamycin and erythromycin (p < 0.05).

CONCLUSIONS: To the best of our knowledge, this is the first report on the relationship of the genotypic diversity, antimicrobial resistance and biofilm-forming abilities of Campylobacter isolated from chicken in Central China, which showed the potential importance of biofilm in antimicrobial resistance. This study will help us better understand the epidemiology and antimicrobial resistance of Campylobacter.}, } @article {pmid29149918, year = {2018}, author = {Daigger, GT and Boltz, JP}, title = {Oxygen Transfer in Moving Bed Biofilm Reactor and Integrated Fixed Film Activated Sludge Processes.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {90}, number = {7}, pages = {615-622}, doi = {10.2175/106143017X15054988926596}, pmid = {29149918}, issn = {1061-4303}, mesh = {Aerobiosis ; *Bioreactors ; Equipment Design/*instrumentation ; Oxygen/*metabolism ; Sewage ; Waste Disposal, Fluid/instrumentation/*methods ; }, abstract = {A demonstrated approach to design the, so-called, medium-bubble air diffusion oxygen transfer system for moving bed biofilm reactor (MBBR) and integrated fixed film activated sludge (IFAS) processes is described. Operational full-scale biological water resource recovery systems treating municipal sewage, designed using this methodology, provide reliable service. Further improvement is possible, however, as knowledge gaps are filled and results in more rationally-based system designs. Pilot-scale testing demonstrates significant enhancement of oxygen transfer capacity from the presence of media. Establishment of the relationship in full-scale systems between diffuser submergence, aeration rate, and biofilm carrier fill fraction will enhance MBBR and IFAS aerobic process design, cost, and performance. Limited testing of full-scale systems prevents computation of alpha values and can be addressed by further full-scale testing under actual operating conditions. Control of MBBR and IFAS aerobic zone oxygen transfer systems can be optimized by recognizing that varying residual dissolved oxygen concentrations are needed, depending on operating conditions. Further application of oxygen transfer control approaches used in activated sludge systems, such as ammonia-based oxygen transfer system control, further improves MBBR and IFAS system energy efficiency.}, } @article {pmid29148361, year = {2018}, author = {Zheng, JX and Bai, B and Lin, ZW and Pu, ZY and Yao, WM and Chen, Z and Li, DY and Deng, XB and Deng, QW and Yu, ZJ}, title = {Characterization of biofilm formation by Enterococcus faecalis isolates derived from urinary tract infections in China.}, journal = {Journal of medical microbiology}, volume = {67}, number = {1}, pages = {60-67}, pmid = {29148361}, issn = {1473-5644}, abstract = {Purpose. This study explored the prevalence and characteristics of Enterococcus faecalis biofilm formation by urinary tract infection (UTI) isolates in order to identify virulence factors associated with biofilm formation.Methodology. A total of 113 E. faecalis isolates were collected from UTI patients in Shenzhen, China. The isolates were subjected to multilocus sequence typing based on housekeeping genes. Biofilms were detected by crystal violet staining and the expression levels of the E. faecalis genes were detected by quantitative real-time PCR.Results/Key findings. The main sequence types (STs) were ST16 and ST179 with the ST16 isolates more likely to form strong biofilms than the ST179 isolates (P=0.008). Strong biofilm formation was more frequently detected in aggregation substance (agg)-positive (+) isolates than in negative (-) isolates (P=0.033). Biofilm formation was also more common in isolates containing enterococcal surface protein (esp), or cytolysin A (cylA)-positive (+) isolates than in isolates negative (-) for these virulence factors. Multivariate regression analysis indicated that cylA [odds ratio (OR), 7.143, P=0.012] was associated with weak biofilm formation, and that agg (OR, 4.471, P=0.004) was associated with strong biofilm formation. The expression of cylA was increased (8.75- to 23.05-fold) in weak biofilm, and the expression of agg was greatly elevated (11.99- to 439.10-fold) in strong biofilm isolates when compared to biofilm-negative isolates.Conclusion. ST16 classification was positively associated with strong biofilm formation in E. faecalis as was agg, while cylA was associated with weak biofilm formation.}, } @article {pmid29146500, year = {2018}, author = {Chakroun, I and Mahdhi, A and Morcillo, P and Cordero, H and Cuesta, A and Bakhrouf, A and Mahdouani, K and Esteban, MÁ}, title = {Motility, biofilm formation, apoptotic effect and virulence gene expression of atypical Salmonella Typhimurium outside and inside Caco-2 cells.}, journal = {Microbial pathogenesis}, volume = {114}, number = {}, pages = {153-162}, doi = {10.1016/j.micpath.2017.11.010}, pmid = {29146500}, issn = {1096-1208}, mesh = {Apoptosis ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Caco-2 Cells ; Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions ; Humans ; Salmonella Infections/*microbiology ; Salmonella typhimurium/cytology/genetics/*physiology ; Seawater/analysis/microbiology ; Sodium Chloride/analysis/metabolism ; Virulence Factors/*genetics/metabolism ; }, abstract = {Disease outbreaks related to waterborne pathogen contamination throughout the world as well as challenges that lie ahead for addressing persistent infection are of renewed interest. In this research, we studied the effects of prolonged exposure of Salmonella enterica serovar Typhimurium to the cues encountered in the extracellular environment particularly in seawater microcosm on bacterial virulence and subsequent infection in Caco-2 cells. Our data show a significant difference in biofilm formation, swimming and swarming motilities between normal and stressed cells of S. Typhimurium under differing NaCl conditions (P < 0.05). Interestingly, adhesion, invasion and apoptotic activity to Caco-2 epithelial cells were determined during infection with normal and stressed Salmonella. Furthermore, we compared the expression of SPI-1 virulence genes (sopA, sopB, sopD, sopE2 and hilA) of normal and stressed S. Typhimurium in response to salt conditions encountered in the extracellular environment in LB broth and after epithelial cell exposure. The interest of the present study is due to the fact that to investigate the bacterial survival strategies during its movement from the natural surroundings to the host cell is fundamental to our understanding of the infection process during the host-pathogen interactions.}, } @article {pmid29145445, year = {2017}, author = {Leite de Andrade, MC and Soares de Oliveira, MA and Santos, FAGD and Ximenes Vilela, PB and da Silva, MN and Macêdo, DPC and de Lima Neto, RG and Neves, HJP and Brandão, ISL and Chaves, GM and de Araujo, RE and Neves, RP}, title = {A new approach by optical coherence tomography for elucidating biofilm formation by emergent Candida species.}, journal = {PloS one}, volume = {12}, number = {11}, pages = {e0188020}, pmid = {29145445}, issn = {1932-6203}, mesh = {*Biofilms ; Candida/classification/*physiology ; Microscopy, Electron, Scanning ; Species Specificity ; Tomography, Optical Coherence/*methods ; }, abstract = {The majority of microorganisms present a community lifestyle, establishing biofilm ecosystems. However, little is known about its formation in emergent Candida species involved in catheter-related infections. Thus, various techniques may be used in the biofilm detection to elucidate structure and clinical impact. In this context, we report the ability of emergent Candida species (Candida haemulonii, C. lusitaniae, C. pelliculosa, C.guilliermondii, C. famata and C. ciferrii) on developing well structured biofilms with cell viability and architecture, using optical coherence tomography (OCT). This new approach was compared with XTT analyses and Scanning Electron Microscopy (SEM). A positive correlation between oxidative activity (XTT) and OCT results (r = 0.8752, p < 0.0001) was observed. SEM images demonstrated cells attachment, multilayer and morphologic characteristics of the biofilm structure. C. lusitaniae was the emergent species which revealed the highest scattering extension length and oxidative metabolism when evaluated by OCT and XTT methods, respectively. Herein, information on C. ciferri biofilm structure were presented for the first time. The OCT results are independently among Candida strains and no species-specific pattern was observed. Our findings strongly contribute for clinical management based on the knowledge of pathogenicity mechanisms involving emergent yeasts.}, } @article {pmid29145328, year = {2017}, author = {Birlutiu, V and Birlutiu, RM}, title = {Endocarditis due to Abiotrophia defectiva, a biofilm-related infection associated with the presence of fixed braces: A case report.}, journal = {Medicine}, volume = {96}, number = {46}, pages = {e8756}, pmid = {29145328}, issn = {1536-5964}, mesh = {*Abiotrophia ; Adult ; *Biofilms ; Braces/*adverse effects/microbiology ; Endocarditis, Bacterial/*microbiology ; Female ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; Pregnancy ; Pregnancy Complications, Infectious/*microbiology ; Prosthesis-Related Infections/*microbiology ; }, abstract = {RATIONALE: Endocarditis with Abiotrophia defectiva represents 4.3% to 6% of all streptococcal endocarditis. The article presents diagnosis issues and the complexity of the treatment.

PATIENT CONCERNS: We present the case of a female white patient, aged 26 years, who developed infectious endocarditis caused by A defectiva, in the last trimester of pregnancy, a biofilm-related infection associated with the presence of fixed braces.

DIAGNOSES: The diagnosis of infectious endocarditis was confirmed by the cardiac ultrasound examination that revealed a voluminous vegetation on the mitral valve, and acute mitral regurgitation caused by chordae tendinae rupture, and also by isolating Abiotrophia defectiva from two positive blood cultures.

INTERVENTIONS: The decision to undergo surgical intervention was taken, and a mitral valve replacement was performed. Surgical intervention that was associated with board-spectrum antibiotic therapy.

OUTCOMES: A defectiva, remains a rare cause of infective endocarditis, with a reserved prognosis that is motivated by the extensive valvular lesions and the risk of embolism.

LESSONS: The use of antibiotics administered in association, in the management of infective endocarditis, is mandatory.}, } @article {pmid29145120, year = {2018}, author = {Meng, J and Li, J and Li, J and Antwi, P and Deng, K and Nan, J and Xu, P}, title = {Enhanced nitrogen removal from piggery wastewater with high NH4[+] and low COD/TN ratio in a novel upflow microaerobic biofilm reactor.}, journal = {Bioresource technology}, volume = {249}, number = {}, pages = {935-942}, doi = {10.1016/j.biortech.2017.10.108}, pmid = {29145120}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Denitrification ; *Nitrogen ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {To enhance nutrient removal more cost-efficiently in microaerobic process treating piggery wastewater characterized by high ammonium (NH4[+]-N) and low chemical oxygen demand (COD) to total nitrogen (TN) ratio, a novel upflow microaerobic biofilm reactor (UMBR) was constructed and the efficiency in nutrient removal was evaluated with various influent COD/TN ratios and reflux ratios. The results showed that the biofilm on the carriers had increased the biomass in the UMBR and enhanced the enrichment of slow-growth-rate bacteria such as nitrifiers, denitrifiers and anammox bacteria. The packed bed allowed the microaerobic biofilm process perform well at a low reflux ratio of 35 with a NH4[+]-N and TN removal as high as 93.1% and 89.9%, respectively. Compared with the previously developed upflow microaerobic sludge reactor, the UMBR had not changed the dominant anammox approach to nitrogen removal, but was more cost-efficiently in treating organic wastewater with high NH4[+]-N and low COD/TN ratio.}, } @article {pmid29144785, year = {2017}, author = {Newton, H and Edwards, J and Mitchell, L and Percival, SL}, title = {Role of slough and biofilm in delaying healing in chronic wounds.}, journal = {British journal of nursing (Mark Allen Publishing)}, volume = {26}, number = {Sup20a}, pages = {S4-S11}, doi = {10.12968/bjon.2017.26.Sup20a.S4}, pmid = {29144785}, issn = {0966-0461}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Burns/pathology/therapy ; Debridement ; Diabetic Foot/pathology/therapy ; Humans ; Occlusive Dressings ; Silver/therapeutic use ; *Wound Healing ; Wound Infection/pathology/*therapy ; }, abstract = {The management of biofilms with maintenance desloughing and antimicrobial therapy is fast becoming the accepted treatment strategy for chronic wounds.}, } @article {pmid29144779, year = {2017}, author = {Pankhurst, S}, title = {Heavily exuding venous leg ulcer with suspected biofilm.}, journal = {British journal of nursing (Mark Allen Publishing)}, volume = {26}, number = {Sup20a}, pages = {S29-S30}, doi = {10.12968/bjon.2017.26.Sup20a.S29}, pmid = {29144779}, issn = {0966-0461}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms ; Exudates and Transudates ; Female ; Humans ; Middle Aged ; *Occlusive Dressings ; Silver/*therapeutic use ; Varicose Ulcer/*therapy ; Wound Healing ; }, } @article {pmid29144778, year = {2017}, author = {Oldfield, R}, title = {Exuding venous leg ulcer with signs of biofilm.}, journal = {British journal of nursing (Mark Allen Publishing)}, volume = {26}, number = {Sup20a}, pages = {S24-S25}, doi = {10.12968/bjon.2017.26.Sup20a.S24}, pmid = {29144778}, issn = {0966-0461}, mesh = {Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; *Biofilms ; Female ; Humans ; *Occlusive Dressings ; Silver/*therapeutic use ; Staphylococcal Infections/therapy ; Staphylococcus aureus ; Varicose Ulcer/microbiology/*therapy ; Wound Healing ; }, } @article {pmid29143262, year = {2018}, author = {Song, C and Yang, CM and Sun, XF and Xia, PF and Qin, J and Guo, BB and Wang, SG}, title = {Influences of graphene oxide on biofilm formation of gram-negative and gram-positive bacteria.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {3}, pages = {2853-2860}, pmid = {29143262}, issn = {1614-7499}, support = {21676161//National Natural Science Foundation of China/ ; 21476130//National Natural Science Foundation of China/ ; 51208283//National Natural Science Foundation of China/ ; }, mesh = {Bacillus subtilis/*drug effects ; Biofilms/*drug effects/growth & development ; Escherichia coli/*drug effects ; Graphite/*toxicity ; Microbial Viability/drug effects ; Oxidative Stress/drug effects ; Oxides ; Water Pollutants, Chemical/*toxicity ; }, abstract = {In this study, we evaluated the influences of graphene oxide (GO) on biofilm formation. Escherichia coli MG1655 and Bacillus subtilis 168 were used as models for Gram-negative and Gram-positive bacteria. The growth profiles and viability assays indicated that GO exhibited a high antibacterial activity, of which the negative effects on bacteria growth raised with the increasing GO concentration. The antibacterial activity of GO was mainly attributed to the membrane stress and ROS-independent oxidative stress. Moreover, it was worthy to note that the biofilm formation was enhanced in the presence of GO at low dosage whereas inhibited in the high-concentration GO environment. These results could be explained by the roles of the dead cells, which were inactivated by GO. When the concentration of GO was limited, only a part of the cells would be inactivated, which may then serve as a protection barrier as well as the necessary nutrient to the remaining living cells for the formation of biofilm. In contrast, with a sufficient presence of GO, almost all cells can be inactivated completely and thus the formation of biofilm could no longer be triggered. Overall, the present work provides significant new insights on the influence of carbon nanomaterials towards biofilm formation, which has far-reaching implications in the field of biofouling and membrane bioreactor. Graphical abstract ᅟ.}, } @article {pmid29142162, year = {2018}, author = {Hayat, S and Sabri, AN and McHugh, TD}, title = {Chloroform extract of turmeric inhibits biofilm formation, EPS production and motility in antibiotic resistant bacteria.}, journal = {The Journal of general and applied microbiology}, volume = {63}, number = {6}, pages = {325-338}, doi = {10.2323/jgam.2017.01.004}, pmid = {29142162}, issn = {1349-8037}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Chloroform/*chemistry ; Curcuma/*chemistry ; Dose-Response Relationship, Drug ; Drug Resistance, Bacterial/*drug effects ; Gas Chromatography-Mass Spectrometry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Polysaccharides, Bacterial/biosynthesis ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {In the form of biofilms, bacteria exhibit more resistance to antibiotics. Biofilm formers can withstand severe conditions and the host's defense system. Therefore, it is necessary to search for effective biofilm inhibitors. In this study, we investigated the effect of a chloroform extract of turmeric on biofilm formation against antibiotic resistant bacteria. The extract exhibited its antibiofilm effect by altering adherence, motility, extracellular polymeric substance (EPS) production and cell surface hydrophobicity; important attributes of biofilm formation. Cell attachment assays indicated that a chloroform extract resulted in a 38.9-60.2% inhibition of cell adherence to a polystyrene surface, and a 44.5-58.3% inhibition to a glass surface. Static biofilm formation assays indicated that a chloroform extract resulted in a 23-74.5% reduction in biofilm formation. The chloroform extract inhibited flagella-directed swarming and swimming motility and pilus-directed twitching motility in a dose-dependent manner. In addition to repression of motility, a chloroform extract also significantly (p < 0.05) altered the hydrophobic behavior, and bacterial strains such as K. pneumoniae and E. cloacae exhibited hydrophilic behavior after the addition of the extract, as compared with control cells. The presence of the extract also significantly (p < 0.05) increased the detachment of biofilms by a surfactant as compared with controls. Fourier transformed infrared spectroscopy (FTIR) had indicated a loss of vital functional groups of polysaccharides and proteins from the EPS of cells treated with a chloroform extract. Gas chromatography mass spectrometry (GC-MS) analysis indicated the presence of many phytochemical constituents, mainly sesquiterpenes and fatty acid groups. These results clearly suggested that turmeric could affect multiple cellular activities in biofilm formers exhibiting antibiotic resistance by modulating adherence, EPS production, motility and surface hydrophobicity.}, } @article {pmid29141147, year = {2018}, author = {Dai, X and Chen, X and Zhao, Y and Yu, Y and Wei, X and Zhang, X and Li, C}, title = {A Water-Soluble Galactose-Decorated Cationic Photodynamic Therapy Agent Based on BODIPY to Selectively Eliminate Biofilm.}, journal = {Biomacromolecules}, volume = {19}, number = {1}, pages = {141-149}, doi = {10.1021/acs.biomac.7b01316}, pmid = {29141147}, issn = {1526-4602}, mesh = {A549 Cells ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Boron Compounds/*pharmacology ; Cations ; Cell Membrane/drug effects ; Cells, Cultured ; Galactose/*chemistry ; Humans ; *Photochemotherapy ; Photosensitizing Agents/*pharmacology ; Reactive Oxygen Species/metabolism ; Solubility ; Water/chemistry ; }, abstract = {A multitude of serious chronic infections are involved in bacterial biofilms that are difficult to eradicate. Here, a water-soluble galactose-functionalized cationic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based photodynamic therapy agent was synthesized for selectively eliminating the bacterial biofilm. These conjugates can capture bacteria to form aggregations through electrostatic interaction and then generate a large number of reactive oxygen species (ROS) under visible light irradiation to kill the bacteria without the emergence of bacterial resistance. Simultaneously, this agent could effectively inhibit and eradicate both Gram-positive and Gram-negative bacterial biofilms. The in-depth analysis of the antimicrobial mechanism confirmed that the conjugates can quickly bind on the bacterial surface, irreversibly disrupt the bacterial membrane, and distinctly inhibit intracellular enzyme activity, ultimately leading to the bacterial death. Importantly, these conjugates are highly selective toward bacterial cells over mammalian cells as well as no cytotoxicity to A549 cells and no discernible hemolytic activity. Collectively, this water-soluble galactose-decorated cationic BODIPY-based photodynamic therapy agent design provides promising insights for the development of therapy for antibiotic-resistant bacteria.}, } @article {pmid29139600, year = {2018}, author = {Robinson, JC and Rostami, N and Casement, J and Vollmer, W and Rickard, AH and Jakubovics, NS}, title = {ArcR modulates biofilm formation in the dental plaque colonizer Streptococcus gordonii.}, journal = {Molecular oral microbiology}, volume = {33}, number = {2}, pages = {143-154}, doi = {10.1111/omi.12207}, pmid = {29139600}, issn = {2041-1014}, mesh = {Arginine/metabolism ; Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; DNA-Binding Proteins/*genetics/*metabolism ; Dental Plaque/*microbiology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Genes, Bacterial/genetics ; Phosphotransferases/genetics/metabolism ; Regulon/genetics ; Repressor Proteins/genetics/metabolism ; Streptococcus gordonii/*genetics/*metabolism ; Trans-Activators/genetics ; }, abstract = {Biofilm formation and cell-cell sensing by the pioneer dental plaque colonizer Streptococcus gordonii are dependent upon arginine. This study aimed to identify genetic factors linking arginine-dependent responses and biofilm formation in S. gordonii. Isogenic mutants disrupted in genes required for the biosynthesis or catabolism of arginine, or for arginine-dependent gene regulation, were screened for their ability to form biofilms in a static culture model. Biofilm formation by a knockout mutant of arcR, encoding an arginine-dependent regulator of transcription, was reduced to < 50% that of the wild-type whereas other strains were unaffected. Complementation of S. gordonii ∆arcR with a plasmid-borne copy of arcR restored the ability to develop biofilms. By DNA microarray analysis, 25 genes were differentially regulated in S. gordonii ∆arcR compared with wild-type under arginine-replete conditions including eight genes encoding components of phosphotransferase systems for sugar uptake. By contrast, disruption of argR or ahrC genes, which encode paralogous arginine-dependent regulators, each resulted in significant changes in the expression of more than 100 genes. Disruption of a gene encoding a putative extracellular protein that was strongly regulated in S. gordonii ∆arcR had a minor impact on biofilm formation. We hypothesize that genes regulated by ArcR form a critical pathway linking arginine sensing to biofilm formation in S. gordonii. Further elucidation of this pathway may provide new targets for the control of dental plaque formation by inhibiting biofilm formation by a key pioneer colonizer of tooth surfaces.}, } @article {pmid29137671, year = {2017}, author = {Ascione, C and Sala, A and Mazaheri-Tehrani, E and Paulone, S and Palmieri, B and Blasi, E and Cermelli, C}, title = {Herpes simplex virus-1 entrapped in Candida albicans biofilm displays decreased sensitivity to antivirals and UVA1 laser treatment.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {16}, number = {1}, pages = {72}, pmid = {29137671}, issn = {1476-0711}, mesh = {Acyclovir/pharmacology ; Animals ; Antiviral Agents/*pharmacology ; Biofilms/growth & development/*radiation effects ; Candida albicans/*metabolism/pathogenicity ; Chlorocebus aethiops ; *Coinfection/drug therapy/radiotherapy ; Foscarnet/pharmacology ; Herpes Simplex/drug therapy/radiotherapy ; Herpesvirus 1, Human/*drug effects/growth & development/pathogenicity/*radiation effects ; *Laser Therapy ; Lasers ; Microbial Sensitivity Tests ; Vero Cells ; }, abstract = {BACKGROUND: Recently, we published data suggesting a mutualistic relationship between HSV-1 and Candida. albicans; in particular: (a) HSV-1 infected macrophages are inhibited in their anti-Candida effector function and (b) Candida biofilm protects HSV-1 from inactivation. The present in vitro study is aimed at testing the effects of Candida biofilm on HSV-1 sensitivity to pharmacological and physical stress, such as antiviral drugs (acyclovir and foscarnet) and laser UVA1 irradiation. We also investigated whether fungus growth pattern, either sessile or planktonic, influences HSV-1 sensitivity to antivirals.

METHODS: Mature Candida biofilms were exposed to HSV-1 and then irradiated with laser light (UVA1, 355 λ). In another set of experiments, mature Candida biofilm were co-cultured with HSV-1 infected VERO cells in the presence of different concentrations of acyclovir or foscarnet. In both protocols, controls unexposed to laser or drugs were included. The viral yield of treated and untreated samples was evaluated by end-point titration. To evaluate whether this protective effect might occur in relation with a different growth pattern, HSV-1 infected cells were co-cultured with either sessile or planktonic forms of Candida and then assessed for susceptibility to antiviral drugs.

RESULTS: UVA1 irradiation caused a 2 Log reduction of virus yield in the control cultures whereas the reduction was only 1 Log with Candida biofilm, regardless to the laser dose applied to the experimental samples (50 or 100 J/cm[2]). The presence of biofilm increased the IC90 from 18.4-25.6 J/cm[2]. Acyclovir caused a 2.3 Log reduction of virus yield in the control cultures whereas with Candida biofilm the reduction was only 0.5 Log; foscarnet determined a reduction of 1.4 Log in the controls and 0.2 Log in biofilm cultures. Consequently, the ICs50 for acyclovir and foscarnet increased by 4- and 12-folds, respectively, compared to controls. When HSV-1 was exposed to either sessile or planktonic fungal cells, the antiviral treatments caused approximately the same weak reduction of virus yield.

CONCLUSIONS: These data demonstrate that: (1) HSV-1 encompassed in Candida biofilm is protected from inactivation by physical (laser) and pharmacological (acyclovir or foscarnet) treatments; (2) the drug antiviral activity is reduced at a similar extent for both sessile or planktonic Candida.}, } @article {pmid29135948, year = {2017}, author = {Krzyściak, W and Kościelniak, D and Papież, M and Vyhouskaya, P and Zagórska-Świeży, K and Kołodziej, I and Bystrowska, B and Jurczak, A}, title = {Effect of a Lactobacillus Salivarius Probiotic on a Double-Species Streptococcus Mutans and Candida Albicans Caries Biofilm.}, journal = {Nutrients}, volume = {9}, number = {11}, pages = {}, pmid = {29135948}, issn = {2072-6643}, mesh = {Biofilms ; *Candida albicans ; Child, Preschool ; Dental Caries/prevention & control ; Dental Plaque ; Female ; Humans ; Ligilactobacillus salivarius/*physiology ; Male ; Probiotics/therapeutic use ; *Streptococcus mutans ; }, abstract = {The aim of the study was to evaluate the anti-cariogenic effects of Lactobacillus salivarius by reducing pathogenic species and biofilm mass in a double-species biofilm model. Coexistence of S. mutans with C. albicans can cause dental caries progression or recurrence of the disease in the future. Fifty-nine children with diagnosed early childhood caries (ECC) were recruited onto the study. The condition of the children's dentition was defined according to the World Health Organization guidelines. The participants were divided into children with initial enamel demineralization and children showing dentin damage. The study was performed on the S. mutans and C. albicans clinical strains, isolated from dental plaque of patients with ECC. The effect of a probiotic containing Lactobacillus salivarius on the ability of S. mutans and C. albicans to produce a double-species biofilm was investigated in an in vitro model. The biomass of the formed/non-degraded biofilm was analyzed on the basis of its crystal violet staining. The number of colonies of S. mutans and C. albicans (CFU/mL, colony forming units/mL) forming the biofilm was determined. Microorganism morphology in the biofilm was evaluated using a scanning electron microscope (SEM). In vitro analysis demonstrated that the presence of S. mutans increased the number of C. albicans colonies (CFU/mL); the double-species biofilm mass and hyphal forms produced in it by the yeast. L. salivarius inhibited the cariogenic biofilm formation of C. albicans and S. mutans. Under the influence of the probiotic; the biofilm mass and the number of S. mutans; C. albicans and S. mutans with C. albicans colonies in the biofilm was decreased. Moreover; it can be noted that after the addition of the probiotic; fungi did not form hyphae or germ tubes of pathogenic potential. These results suggest that L. salivarius can secrete intermediates capable of inhibiting the formation of cariogenic S. mutans and C. albicans biofilm; and may inhibit fungal morphological transformation and thereby reduce the pathogenicity of C. albicans; weakening its pathogenic potential. Further research is required to prove or disprove the long-term effects of the preparation and to achieve preventive methods.}, } @article {pmid29135250, year = {2017}, author = {Choi, H and Ham, SY and Cha, E and Shin, Y and Kim, HS and Bang, JK and Son, SH and Park, HD and Byun, Y}, title = {Structure-Activity Relationships of 6- and 8-Gingerol Analogs as Anti-Biofilm Agents.}, journal = {Journal of medicinal chemistry}, volume = {60}, number = {23}, pages = {9821-9837}, doi = {10.1021/acs.jmedchem.7b01426}, pmid = {29135250}, issn = {1520-4804}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Catechols/chemistry/*pharmacology ; Fatty Alcohols/chemistry/*pharmacology ; Humans ; Molecular Docking Simulation ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; Quorum Sensing/drug effects ; Trans-Activators/metabolism ; }, abstract = {Pseudomonas aeruginosa is a causative agent of chronic infections in immunocompromised patients. Disruption of quorum sensing circuits is an attractive strategy for treating diseases associated with P. aeruginosa infection. In this study, we designed and synthesized a series of gingerol analogs targeting LasR, a master regulator of quorum sensing networks in P. aeruginosa. Structure-activity relationship studies showed that a hydrogen-bonding interaction in the head section, stereochemistry and rotational rigidity in the middle section, and optimal alkyl chain length in the tail section are important factors for the enhancement of LasR-binding affinity and for the inhibition of biofilm formation. The most potent compound 41, an analog of (R)-8-gingerol with restricted rotation, showed stronger LasR-binding affinity and inhibition of biofilm formation than the known LasR antagonist (S)-6-gingerol. This new LasR antagonist can be used as an early lead compound for the development of anti-biofilm agents to treat P. aeruginosa infections.}, } @article {pmid29134332, year = {2018}, author = {Xia, J and Chen, J and Chen, Y and Qian, G and Liu, F}, title = {Type IV pilus biogenesis genes and their roles in biofilm formation in the biological control agent Lysobacter enzymogenes OH11.}, journal = {Applied microbiology and biotechnology}, volume = {102}, number = {2}, pages = {833-846}, doi = {10.1007/s00253-017-8619-4}, pmid = {29134332}, issn = {1432-0614}, support = {31371981 and 31572046//National Natural Science Foundation of China/ ; }, mesh = {Adenosine Triphosphatases/metabolism ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Biological Control Agents ; Fimbriae Proteins/*genetics ; Fimbriae, Bacterial/metabolism ; Lysobacter/*genetics/*metabolism ; Molecular Motor Proteins/metabolism ; Mutation ; }, abstract = {Type IV pilus (T4P) is widespread in bacteria, yet its biogenesis mechanism and functionality is only partially elucidated in a limited number of bacterial species. Here, by using strain OH11 as the model organism, we reported the identification of 26 T4P structural or functional component (SFC) proteins in the Gram-negative Lysobacter enzymogenes, which is a biocontrol agent potentially exploiting T4P-mediated twitching motility for antifungal activity. Twenty such SFC coding genes were individually knocked-out in-frame to create a T4P SFC deletion library. By using combined phenotypic and genetic approaches, we found that 14 such SFCs, which were expressed from four operons, were essential for twitching motility. These SFCs included the minor pilins (PilEi, PilXi, PilVi, and FimTi), the anti-retraction protein PilY1i, the platform protein PilC, the extension/extraction ATPases (PilB, PilT, and PilU), and the PilMNOPQ complex. Among these, mutation of pilT or pilU caused a hyper piliation, while the remaining 12 SFCs were indispensable for pilus formation. Ten (FimTi, PilY1i, PilB, PilT, PilU, and the PilMNOPQ complex) of the 14 SFC proteins, as well as PilA, were further shown to play a key role in L. enzymogenes biofilm formation. Overall, our results provide the first report to dissect the genetic basis of T4P biogenesis and its role in biofilm formation in L. enzymogenes in detail, which can serve as an alternative platform for studying T4P biogenesis and its antifungal function.}, } @article {pmid29134109, year = {2017}, author = {Yoshii, Y and Okuda, KI and Yamada, S and Nagakura, M and Sugimoto, S and Nagano, T and Okabe, T and Kojima, H and Iwamoto, T and Kuwano, K and Mizunoe, Y}, title = {Erratum: Author Correction: Norgestimate inhibits staphylococcal biofilm formation and resensitizes methicillin-resistant Staphylococcus aureus to β-lactam antibiotics.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {30}, doi = {10.1038/s41522-017-0038-x}, pmid = {29134109}, issn = {2055-5008}, abstract = {[This corrects the article DOI: 10.1038/s41522-017-0026-1.].}, } @article {pmid29134108, year = {2017}, author = {Xu, W and Flores-Mireles, AL and Cusumano, ZT and Takagi, E and Hultgren, SJ and Caparon, MG}, title = {Host and bacterial proteases influence biofilm formation and virulence in a murine model of enterococcal catheter-associated urinary tract infection.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {28}, pmid = {29134108}, issn = {2055-5008}, support = {F32 DK104516/DK/NIDDK NIH HHS/United States ; P50 DK064540/DK/NIDDK NIH HHS/United States ; R01 AI108749/AI/NIAID NIH HHS/United States ; R01 DK051406/DK/NIDDK NIH HHS/United States ; }, abstract = {Enterococcus faecalis is a leading causative agent of catheter-associated urinary tract infection (CAUTI), the most common hospital-acquired infection. Its ability to grow and form catheter biofilm is dependent upon host fibrinogen (Fg). Examined here are how bacterial and host proteases interact with Fg and contribute to virulence. Analysis of mutants affecting the two major secreted proteases of E. faecalis OG1RF (GelE, SprE) revealed that while the loss of either had no effect on virulence in a murine CAUTI model or for formation of Fg-dependent biofilm in urine, the loss of both resulted in CAUTI attenuation and defective biofilm formation. GelE[-], but not SprE[-] mutants, lost the ability to degrade Fg in medium, while paradoxically, both could degrade Fg in urine. The finding that SprE was activated independently of GelE in urine by a host trypsin-like protease resolved this paradox. Treatment of catheter-implanted mice with inhibitors of both host-derived and bacterial-derived proteases dramatically reduced catheter-induced inflammation, significantly inhibited dissemination from bladder to kidney and revealed an essential role for a host cysteine protease in promoting pathogenesis. These data show that both bacterial and host proteases contribute to CAUTI, that host proteases promote dissemination and suggest new strategies for therapeutic intervention.}, } @article {pmid29133243, year = {2018}, author = {Von Borowski, RG and Macedo, AJ and Gnoatto, SCB}, title = {Peptides as a strategy against biofilm-forming microorganisms: Structure-activity relationship perspectives.}, journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences}, volume = {114}, number = {}, pages = {114-137}, doi = {10.1016/j.ejps.2017.11.008}, pmid = {29133243}, issn = {1879-0720}, mesh = {Amino Acid Sequence ; Animals ; Anti-Infective Agents/*administration & dosage/*chemistry ; Biofilms/*drug effects/growth & development ; Humans ; Peptide Fragments/*administration & dosage/*chemistry/genetics ; Structure-Activity Relationship ; }, abstract = {Biofilm forming microorganisms substantially enhance their virulence and drug resistance causing and alternatives are need to combat this health problem. In this context, peptides are an exceptional strategy in drug design and pharmaceutical innovation due to their diverse chemical features, biological activity and biotechnological relevance. Therefore, this study proposes a comprehensive assessment of a wide range of peptides, targeting biofilms. It provides chemical and molecular information and a Structural Activity Relationship perspective in order to delineate minimal requirements for antibiofilm activity and contributing to the development of new antibiofilm agents. In light of this, it was possible to propose a peptide design model (X1-X2-X3-X4-X5-X6-X7-X8-X9-X10-X11-X12-X13-X14-X15-X16-X17-X18-X19-X20) to be tested in the war against resistant microorganisms.}, } @article {pmid29133157, year = {2018}, author = {Soldini, S and Posteraro, B and Vella, A and De Carolis, E and Borghi, E and Falleni, M and Losito, AR and Maiuro, G and Trecarichi, EM and Sanguinetti, M and Tumbarello, M}, title = {Microbiologic and clinical characteristics of biofilm-forming Candida parapsilosis isolates associated with fungaemia and their impact on mortality.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {24}, number = {7}, pages = {771-777}, doi = {10.1016/j.cmi.2017.11.005}, pmid = {29133157}, issn = {1469-0691}, mesh = {Aged ; Aged, 80 and over ; Animals ; Antifungal Agents/pharmacology/therapeutic use ; Biofilms/drug effects/*growth & development ; Biological Assay ; Candida parapsilosis/drug effects/isolation & purification/*pathogenicity/*physiology ; Candidemia/drug therapy/*microbiology/*mortality ; Catheter-Related Infections/drug therapy/microbiology/mortality ; Cause of Death ; Female ; Humans ; Italy ; Lepidoptera/microbiology ; Male ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Survival Analysis ; Virulence ; }, abstract = {OBJECTIVES: Biofilm formation (BF) by fungal isolates may dramatically complicate infection. We determined the ability of Candida parapsilosis isolates from single fungaemia episodes to form biofilms and we analysed biofilm subgroups for antifungal susceptibility and pathogenic potential. We then correlated BF with clinical characteristics and outcomes of the episodes.

METHODS: BF was measured using the crystal violet biomass assay. Antifungal susceptibility of preformed biofilms was assessed, and virulence was studied using the Galleria mellonella model. A retrospective analysis of patients' clinical records was performed.

RESULTS: Of 190 patient-unique isolates, 84, 38 and 68 were identified as having high BF (HBF), moderate BF (MBF) or low BF (LBF), respectively. Among 30 randomly selected isolates, nine (eight HBF and one MBF), six (all HBF) and one (HBF) isolates had elevated sessile minimum inhibitory concentrations to fluconazole, anidulafungin or amphotericin B; all HBF and MBF isolates had elevated voriconazole sessile minimum inhibitory concentrations. G. mellonella killing rates of HBF isolates were significantly greater than MBF (or LBF) isolates (50% vs. 20%, 2 days from infection). By comparing HBF/MBF (106 patients) and LBF (84 patients) groups, we found that HBF/MBF patients had more central venous catheter-related fungaemias (62/106 (58.5%) vs. 29/84 (34.5%), p 0.001) and were more likely to die at 30 days from fungaemia onset (61/106 (57.5%) vs. 28/84 (33.3%), p 0.01). In the HBF/MBF group, azole antifungal therapy and central venous catheter removal were significantly associated with a higher and lower 30-day mortality rate, respectively.

CONCLUSIONS: C. parapsilosis BF influences the clinical outcome in patients with fungaemia.}, } @article {pmid29132122, year = {2018}, author = {Sun, J and Ni, BJ and Sharma, KR and Wang, Q and Hu, S and Yuan, Z}, title = {Modelling the long-term effect of wastewater compositions on maximum sulfide and methane production rates of sewer biofilm.}, journal = {Water research}, volume = {129}, number = {}, pages = {58-65}, doi = {10.1016/j.watres.2017.11.007}, pmid = {29132122}, issn = {1879-2448}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Kinetics ; Methane/*metabolism ; *Models, Theoretical ; *Sewage ; Sulfates ; Sulfides/*metabolism ; Wastewater ; }, abstract = {Reliable modelling of sulfide and methane production in sewer systems is required for efficient sewer emission management. Wastewater compositions affect sulfide and methane production kinetics through both its short-term variation influencing the substrate availability to sewer biofilms, and its long-term variation affecting the sewer biofilm structure. While the short-term effect is well considered in existing sewer models with the use of Monod or half-order equations, the long-term effect has not been explicitly considered in current sewer models suitable for network modelling. In this study, the long-term effect of wastewater compositions on sulfide and methane production activities in rising main sewers was investigated. A detailed biofilm model was firstly developed, and then calibrated and validated using experimental data measured during the entire biofilm development period of a laboratory sewer reactor. Based on scenario simulations using the detailed biofilm model, empirical equations describing the long-term effect of sulfate and sCOD (soluble chemical oxygen demand) concentrations on kH2S (the maximum sulfide production rate of sewer biofilm) and kCH4 (the maximum methane production rate of sewer biofilm) were proposed. These equations require further verification in future studies before their potential integration into network-wide sewer models.}, } @article {pmid29132011, year = {2018}, author = {Pinto, D and Coradin, T and Laberty-Robert, C}, title = {Effect of anode polarization on biofilm formation and electron transfer in Shewanella oneidensis/graphite felt microbial fuel cells.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {120}, number = {}, pages = {1-9}, doi = {10.1016/j.bioelechem.2017.10.008}, pmid = {29132011}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/*microbiology ; *Biofilms ; Electricity ; Electrochemical Techniques/instrumentation ; Electrodes ; Electron Transport ; Graphite/*chemistry ; Porosity ; Shewanella/*physiology ; }, abstract = {In microbial fuel cells, electricity generation is assumed by bacterial degradation of low-grade organics generating electrons that are transferred to an electrode. The nature and efficiency of the electron transfer from the bacteria to the electrodes are determined by several chemical, physical and biological parameters. Specifically, the application of a specific potential at the bioanode has been shown to stimulate the formation of an electro-active biofilm, but the underlying mechanisms remain poorly understood. In this study, we have investigated the effect of an applied potential on the formation and electroactivity of biofilms established by Shewanella oneidensis bacteria on graphite felt electrodes in single- and double-chamber reactor configurations in oxic conditions. Using amperometry, cyclic voltammetry, and OCP/Power/Polarization curves techniques, we showed that a potential ranging between -0.3V and +0.5V (vs. Ag/AgCl/KCl sat.) and its converse application to a couple of electrodes leads to different electrochemical behaviors, anodic currents and biofilm architectures. For example, when the bacteria were confined in the anodic compartment of a double-chamber cell, a negative applied potential (-0.3V) at the bioanode favors a mediated electron transfer correlated with the progressive formation of a biofilm that fills the felt porosity and bridges the graphite fibers. In contrast, a positive applied potential (+0.3V) at the bioanode stimulates a direct electron transfer resulting in the fast-bacterial colonization of the fibers only. These results provide significant insight for the understanding of the complex bacteria-electrode interactions in microbial fuel cells.}, } @article {pmid29131752, year = {2017}, author = {Percival, SL and Mayer, D and Malone, M and Swanson, T and Gibson, D and Schultz, G}, title = {Surfactants and their role in wound cleansing and biofilm management.}, journal = {Journal of wound care}, volume = {26}, number = {11}, pages = {680-690}, doi = {10.12968/jowc.2017.26.11.680}, pmid = {29131752}, issn = {0969-0700}, mesh = {*Bandages ; *Biofilms ; Humans ; Poloxamer/*therapeutic use ; Surface-Active Agents/*therapeutic use ; Wound Infection/*therapy ; Wounds and Injuries/*therapy ; }, abstract = {Surfactants are widely used as detergents, emulsifiers, wetting agents, foaming agents and dispersants in the cosmetics, hygiene, food and oil industries. Their use in a clinical setting is also common, particularly within the field of wound care. Many wound cleansers contain surfactants and subsequently there is available data that shows the growing potential of these wound cleansers in the enhancement of wound closure. The presence of microorganisms in wounds has been recognised as a significant factor that delay healing. In complex or chronic wounds that are complicated by biofilms, persistent inflammation or the production of non-viable tissue and slough, the use of surfactants has been shown to aid in the removal of these barriers to wound healing. The use of concentrated surfactant(poloxamer) based wound dressings represent an important component of wound management. Consequently, this article will discuss the effect of clinically used surfactants, with specific focus on a concentrated poloxamer for use against wound biofilm.}, } @article {pmid29131083, year = {2017}, author = {Weerasekera, MM and Jayarathna, TA and Wijesinghe, GK and Gunasekara, CP and Fernando, N and Kottegoda, N and Samaranayake, LP}, title = {The Effect of Nutritive and Non-Nutritive Sweeteners on the Growth, Adhesion, and Biofilm Formation of Candida albicans and Candida tropicalis.}, journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre}, volume = {26}, number = {6}, pages = {554-560}, pmid = {29131083}, issn = {1423-0151}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candida tropicalis/*drug effects ; Glucose/pharmacology ; Humans ; Microscopy, Electron, Scanning ; Non-Nutritive Sweeteners/*pharmacology ; Nutritive Sweeteners/*pharmacology ; Plankton/drug effects ; Saccharin/pharmacology ; Sucrose/pharmacology ; }, abstract = {OBJECTIVE: To determine the effect of glucose, sucrose, and saccharin on growth, adhesion, and biofilm formation of Candida albicans and Candida tropicalis.

MATERIALS AND METHODS: The growth rates of mono-cultures of planktonic C. albicans and C. tropicalis and 1:1 mixed co-cultures were determined in yeast nitrogen broth supplemented with 5% (30 mM) and 10% (60 mM) glucose, sucrose, and saccharin, using optical density measurements at 2-h intervals over a 14-h period. Adhesion and biofilm growth were performed and the growth quantified using a standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The biofilm architecture was visualized using scanning electron microscopy. One- and two-way analysis of variance (ANOVA) was performed to analyse the differences among multiple means.

RESULTS: The highest planktonic growth was noted in 5% glucose after 14 h (p < 0.05). No significant planktonic growth was observed in either concentration of saccharin. Both the concentrations of glucose and sucrose elicited significantly increased adhesion from MTT activity of 0.017 to >0.019 in mono- as well as co-cultures (p < 0.05), whilst the lower concentration of saccharin significantly dampened the adhesion. Maximal biofilm growth was observed in both species with the lower concentration of sucrose (5%), although a similar concentration of saccharin abrogated biofilm development: the highest MTT value (>0.35) was obtained for glucose and the lowest (>0.15) for saccharin.

CONCLUSION: In this study, glucose and sucrose accelerated the growth, adhesion, and biofilm formation of Candida species. However, the non-nutritive sweetener saccharin appeared to dampen, and in some instances suppress, these virulent attributes of Candida.}, } @article {pmid29130160, year = {2018}, author = {Thornhill, SG and McLean, RJC}, title = {Use of Whole-Cell Bioassays for Screening Quorum Signaling, Quorum Interference, and Biofilm Dispersion.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1673}, number = {}, pages = {3-24}, doi = {10.1007/978-1-4939-7309-5_1}, pmid = {29130160}, issn = {1940-6029}, mesh = {Acetates/chemistry ; Acyl-Butyrolactones/pharmacology ; Agrobacterium tumefaciens/drug effects/physiology ; *Biofilms/drug effects ; Biological Assay/*methods ; Chromatography, Thin Layer ; Chromobacterium/drug effects/physiology ; *Quorum Sensing/drug effects ; }, abstract = {In most bacteria, a global level of regulation, termed quorum sensing (QS), exists involving intercellular communication via the production and response to cell density-dependent signal molecules. QS has been associated with a number of important features in bacteria including virulence regulation and biofilm formation. Consequently, there is considerable interest in understanding, detecting, and inhibiting QS. N-acylated homoserine lactones (AHLs) are used as extracellular QS signals by a variety of Gram-negative bacteria. Chromobacterium violaceum, commonly found in soil and water, produces the characteristic purple pigment violacein, regulated by AHL-mediated QS. Based on this readily observed pigmentation phenotype, C. violaceum strains can be used to detect various aspects of AHL-mediated QS activity. In another commonly used bioassay organism, Agrobacterium tumefaciens, QS can be detected by the use of a reporter gene such as lacZ. Here, we describe several commonly used approaches incorporating C. violaceum and A. tumefaciens that can be used to detect AHL and QS inhibitors. Due to the inherent low susceptibility of biofilm bacteria to antimicrobial agents, biofilm dispersion, whereby bacteria reenter the planktonic community, is another increasingly important area of research. At least one signal, distinct from traditional QS, has been identified and there are a variety of other environmental factors that also trigger dispersion. We describe a microtiter-based experimental strategy whereby potential biofilm dispersion compounds can be screened.}, } @article {pmid29130039, year = {2017}, author = {Feldman, M and Shenderovich, J and Lavy, E and Friedman, M and Steinberg, D}, title = {A Sustained-Release Membrane of Thiazolidinedione-8: Effect on Formation of a Candida/Bacteria Mixed Biofilm on Hydroxyapatite in a Continuous Flow Model.}, journal = {BioMed research international}, volume = {2017}, number = {}, pages = {3510124}, pmid = {29130039}, issn = {2314-6141}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects ; Delayed-Action Preparations ; Durapatite/*pharmacology ; Kinetics ; *Membranes, Artificial ; *Models, Theoretical ; Polysaccharides, Bacterial/chemistry ; *Rheology ; Streptococcus mutans/*drug effects ; Surface Properties ; Thiazolidinediones/*pharmacology ; }, abstract = {Thiazolidinediones (TZDs) have been found to act as effective quorum sensing quenchers, capable of preventing biofilm formation. Our previous studies demonstrated a profound antibiofilm effect of the TZD derivative thiazolidinedione-8 (S-8), either in solution or incorporated into a sustained-release membrane (SRM-S-8) under batch conditions. In the present study, we used a constant depth film fermenter model in order to investigate the impact of SRM-S-8 on mixed C. albicans-S. mutans biofilm development, under flow conditions. We found that essential parameters of cospecies biofilm maintenance and maturation, such as metabolic activity, biofilm thickness, roughness, extracellular polysaccharides production, and morphology of both pathogens, were altered by SRM-S-8 in the flow system. We propose that prolonged and sustained release of S-8 in a flow-through system allows better penetration of the active agent to deeper layers of the mixed biofilm, thereby increasing its activity against both pathogens. In conclusion, the use of a locally applied sustained-release drug delivery system of S-8 can affect the dental polymicrobial biofilm, resulting in clinical improvements and a better patient compliance.}, } @article {pmid29128733, year = {2018}, author = {Hu, L}, title = {Prevalence of curli genes among Cronobacter species and their roles in biofilm formation and cell-cell aggregation.}, journal = {International journal of food microbiology}, volume = {265}, number = {}, pages = {65-73}, doi = {10.1016/j.ijfoodmicro.2017.10.031}, pmid = {29128733}, issn = {1879-3460}, mesh = {Bacterial Adhesion/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cronobacter/*genetics/isolation & purification/*pathogenicity ; Enterobacteriaceae Infections/microbiology ; Fimbriae, Bacterial/*genetics ; Foodborne Diseases/microbiology ; Humans ; Infant, Newborn ; }, abstract = {Cronobacter species are food-borne opportunistic pathogens that cause sepsis, meningitis, and necrotizing enterocolitis in neonates. Bacterial pathogens such as pathogenic Escherichia coli and Salmonella species express extracellular curli fimbriae that are involved in rugosity, biofilm formation, and host cell adherence. csgBAC operon encodes the major curli structural subunit CsgA and the nucleator protein CsgB. csgDEFG operon encodes the regulatory protein CsgD and putative assembly factors. In this study, the curli operons were analyzed in the sequences of 13 Cronobacter strains and other enteric bacterial pathogens. Isogenic mutants of csgA and csgB were generated in C. turicensis LMG23827 (z3032). csgA and csgB mutants did not express curli fimbriae as indicated by a lack of Congo red binding and absence of curli by electron microscopic evaluation. Compared to the wild type strain, biofilm formation and cell-cell aggregation of csgA and csgB mutants were remarkably decreased. The prevalence of curli operons were investigated in 231 Cronobacter strains isolated from different sources using polymerase chain reaction (PCR) assay. The results of the PCR analysis showed that csgA and csgG were present in 30% clinical isolates, 8% food, and 11% environmental isolates. These genes were present in C. dublinensis, C. malonaticus, C. turicensis, and C. universalis, but not in C. muytjensii and C. sakazakii. Our data indicate that csgBAC and csgDEFG operons were present about three fold higher in clinical isolates than in isolates from other sources. The csgA and csgB genes were shown to be involved in the early stages of biofilm development and cell-cell aggregation in Cronobacter.}, } @article {pmid29127641, year = {2018}, author = {Singh, A and Kamble, SJ and Sawant, M and Chakravarthy, Y and Kazmi, A and Aymerich, E and Starkl, M and Ghangrekar, M and Philip, L}, title = {Technical, hygiene, economic, and life cycle assessment of full-scale moving bed biofilm reactors for wastewater treatment in India.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {3}, pages = {2552-2569}, pmid = {29127641}, issn = {1614-7499}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Hygiene ; India ; Waste Disposal, Fluid/*methods ; Wastewater/*analysis ; }, abstract = {Moving bed biofilm reactor (MBBR) is a highly effective biological treatment process applied to treat both urban and industrial wastewaters in developing countries. The present study investigated the technical performance of ten full-scale MBBR systems located across India. The biochemical oxygen demand, chemical oxygen demand, total suspended solid, pathogens, and nutrient removal efficiencies were low as compared to the values claimed in literature. Plant 1 was considered for evaluation of environmental impacts using life cycle assessment approach. CML 2 baseline 2000 methodology was adopted, in which 11 impact categories were considered. The life cycle impact assessment results revealed that the main environmental hot spot of this system was energy consumption. Additionally, two scenarios were compared: scenario 1 (direct discharge of treated effluent, i.e., no reuse) and scenario 2 (effluent reuse and tap water replacement). The results showed that scenario 2 significantly reduce the environmental impact in all the categories ultimately decreasing the environmental burden. Moreover, significant economic and environmental benefits can be obtained in scenario 2 by replacing the freshwater demand for non-potable uses. To enhance the performance of wastewater treatment plant (WWTP), there is a need to optimize energy consumption and increase wastewater collection efficiency to maximize the operating capacity of plant and minimize overall environmental footprint. It was concluded that MBBR can be a good alternative for upgrading and optimizing existing municipal wastewater treatment plants with appropriate tertiary treatment. Graphical abstract ᅟ.}, } @article {pmid29127029, year = {2018}, author = {Yatip, P and Nitin Chandra Teja, D and Flegel, TW and Soowannayan, C}, title = {Extract from the fermented soybean product Natto inhibits Vibrio biofilm formation and reduces shrimp mortality from Vibrio harveyi infection.}, journal = {Fish & shellfish immunology}, volume = {72}, number = {}, pages = {348-355}, doi = {10.1016/j.fsi.2017.11.008}, pmid = {29127029}, issn = {1095-9947}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Bacillus subtilis/*physiology ; Biofilms/*drug effects ; Penaeidae/*immunology ; Plant Extracts/pharmacology ; Soy Foods/analysis ; Vibrio/*drug effects/*physiology ; }, abstract = {Many bacteria, including Vibrio pathogens of shrimp, need to colonize and/or form biofilms in hosts or the environment to cause disease. Thus, one possible control strategy for shrimp Vibriosis is biofilm inhibition. With this objective, an extract from the Japanese fermented soybean product, Natto was tested with the luminescent shrimp pathogen Vibrio harveyi (VH) for its ability to inhibit or degrade biofilm and to interfere with cell growth in broth. Natto is a traditional fermentation product of Bacillus subtilis var Natto (BSN1). Using 96 well microtiter plates coated with 0.4% chitosan, we found that biofilm formation by VH was inhibited, while growth in parallel broth cultures was not. When an extract from Natto prepared using BSN1 was mixed with feed for the whiteleg shrimp Penaeus vannamei before immersion challenge with V. harveyi at 10[6] cfu/ml, survival was significantly higher (p≤0.05) than for control shrimp given feed without these additives. Further work done to test whether d-amino acids were involved in biofilm formation as previously reported for B. subtilis, Staphylococus aureus and Pseudomonas aeruginosa gave negative results. In conclusion, we discovered that Natto extract can inhibit Vibrio biofilm formation and that it or BSN1 alone added to shrimp feed can significantly reduce shrimp mortality in immersion challenges with pathogenic VH. This shows some promise for possible application against Vibriosis in shrimp since Natto is generally regarded as safe (GRAS) for human consumption.}, } @article {pmid29126739, year = {2018}, author = {Liu, N and Zhong, H and Tu, J and Jiang, Z and Jiang, Y and Jiang, Y and Jiang, Y and Li, J and Zhang, W and Wang, Y and Sheng, C}, title = {Discovery of simplified sampangine derivatives as novel fungal biofilm inhibitors.}, journal = {European journal of medicinal chemistry}, volume = {143}, number = {}, pages = {1510-1523}, doi = {10.1016/j.ejmech.2017.10.043}, pmid = {29126739}, issn = {1768-3254}, mesh = {Alkaloids/*chemistry/*pharmacology/toxicity ; Antifungal Agents/chemistry/pharmacology/toxicity ; Biofilms/*drug effects/*growth & development ; Drug Resistance, Fungal/drug effects ; Fungi/*drug effects/*physiology ; Heterocyclic Compounds, 4 or More Rings/chemistry/pharmacology/toxicity ; Microbial Sensitivity Tests ; Naphthyridines ; }, abstract = {Lack of novel antifungal agents and severe drug resistance have led to high incidence and associated mortality of invasive fungal infections. To tackle the challenges, novel antifungal agents with new chemotype, fungicidal activity and anti-resistant potency are highly desirable. On the basis of our previously identified simplified analogue of antifungal natural product sampangine, systemic structure-activity relationships were clarified and two novel derivatives showed promising features as novel antifungal lead compounds. Compounds 22b and 22c showed good fungicidal activity against both fluconazole-sensitive and fluconazole-resistant Candida albicans strains. Moreover, they were proven to be potent inhibitors of Candida albicans biofilm formation and yeast-to-hypha morphological transition by down-regulating biofilm-associated genes. In a rat vaginal Candida albicans infection model, compounds 22b and 22c showed excellent therapeutic effects with low toxicity. The results highlighted the potential of sampangine derivatives to overcome fluconazole-related and biofilm-related drug resistance.}, } @article {pmid29125461, year = {2017}, author = {Jani, S and Seely, AL and Peabody V, GL and Jayaraman, A and Manson, MD}, title = {Chemotaxis to self-generated AI-2 promotes biofilm formation in Escherichia coli.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {12}, pages = {1778-1790}, doi = {10.1099/mic.0.000567}, pmid = {29125461}, issn = {1465-2080}, abstract = {Responses to the interspecies quorum-sensing signal autoinducer-2 (AI-2) regulate the patterns of gene expression that promote biofilm development. Escherichia coli also senses AI-2 as a chemoattractant, a response that requires the periplasmic AI-2-binding protein LsrB and the chemoreceptor Tsr. Here, we confirm, as previously observed, that under static conditions highly motile E. coli cells self-aggregate and form surface-adherent structures more readily than cells lacking LsrB and Tsr, or than ΔluxS cells unable to produce AI-2. This difference is observed both at 37 and 30 °C. Cells deleted for the genes encoding the lsrACDBFG operon repressor (ΔlsrR), or the AI-2 kinase (ΔlsrK), or an AI-2 uptake channel protein (ΔlsrC), or an AI-2 metabolism enzyme (ΔlsrG) are also defective in biofilm formation. The Δtsr and ΔlsrB cells are totally defective in AI-2 chemotaxis, whereas the other mutants show normal or near-normal chemotaxis to external gradients of AI-2. These data demonstrate that chemotaxis to external AI-2 is necessary but not sufficient to induce the full range of density-dependent behaviours that are required for optimal biofilm formation. We also demonstrate that, compared to other binding-protein-dependent chemotaxis systems in E. coli, low levels (on the order of ~250 molecules of periplasmic LsrB per wild-type cell and as low as ~50 molecules per cell in some mutants) are adequate for a strong chemotaxis response to external gradients of AI-2.}, } @article {pmid29125121, year = {2017}, author = {Zeng, L and Zhang, L and Wang, P and Meng, G}, title = {Structural basis of host recognition and biofilm formation by Salmonella Saf pili.}, journal = {eLife}, volume = {6}, number = {}, pages = {}, pmid = {29125121}, issn = {2050-084X}, mesh = {Bacterial Adhesion ; Bacterial Proteins/*chemistry/*metabolism ; Biofilms/*growth & development ; Crystallography, X-Ray ; Fimbriae, Bacterial/*physiology ; Models, Molecular ; Protein Binding ; Protein Conformation ; Protein Multimerization ; Salmonella typhimurium/*physiology ; }, abstract = {Pili are critical in host recognition, colonization and biofilm formation during bacterial infection. Here, we report the crystal structures of SafD-dsc and SafD-SafA-SafA (SafDAA-dsc) in Saf pili. Cell adherence assays show that SafD and SafA are both required for host recognition, suggesting a poly-adhesive mechanism for Saf pili. Moreover, the SafDAA-dsc structure, as well as SAXS characterization, reveals an unexpected inter-molecular oligomerization, prompting the investigation of Saf-driven self-association in biofilm formation. The bead/cell aggregation and biofilm formation assays are used to demonstrate the novel function of Saf pili. Structure-based mutants targeting the inter-molecular hydrogen bonds and complementary architecture/surfaces in SafDAA-dsc dimers significantly impaired the Saf self-association activity and biofilm formation. In summary, our results identify two novel functions of Saf pili: the poly-adhesive and self-associating activities. More importantly, Saf-Saf structures and functional characterizations help to define a pili-mediated inter-cellular oligomerizaiton mechanism for bacterial aggregation, colonization and ultimate biofilm formation.}, } @article {pmid29124967, year = {2018}, author = {Berríos, P and Fuentes, JA and Salas, D and Carreño, A and Aldea, P and Fernández, F and Trombert, AN}, title = {Inhibitory effect of biofilm-forming Lactobacillus kunkeei strains against virulent Pseudomonas aeruginosa in vitro and in honeycomb moth (Galleria mellonella) infection model.}, journal = {Beneficial microbes}, volume = {9}, number = {2}, pages = {257-268}, doi = {10.3920/BM2017.0048}, pmid = {29124967}, issn = {1876-2891}, mesh = {Animals ; Biofilms/*growth & development ; Lactobacillus/growth & development/*physiology ; Moths/*microbiology ; *Probiotics ; Pseudomonas aeruginosa/growth & development/*physiology ; }, abstract = {Biofilms correspond to complex communities of microorganisms embedded in an extracellular polymeric matrix. Biofilm lifestyle predominates in Pseudomonas aeruginosa, an opportunistic Gram negative pathogen responsible for a wide spectrum of infections in humans, plants and animals. In this context, anti-biofilm can be considered a key strategy to control P. aeruginosa infections, thereby more research in the field is required. On the other hand, Lactobacillus species have been described as beneficial due to their anti-biofilm properties and their consequent effect against a wide spectrum of pathogens. In fact, biofilm-forming Lactobacilli seem to be more efficient than their planktonic counterpart to antagonise pathogenic bacteria. In this work, we demonstrated that Lactobacillus kunkeei, a novel Lactobacillus species isolated from honeybee guts, can form biofilms in vitro. In addition, the L. kunkeei biofilm can, in turn, inhibit the formation of P. aeruginosa biofilms. Finally, we found that L. kunkeei strains attenuate infection of P. aeruginosa in the Galleria mellonella model, presumably by affecting P. aeruginosa biofilm formation and/or their stability. Since L. kunkeei presents characteristics of a probiotic, this work provides evidence arguing that the use of this Lactobacillus species in both animals (including insects) and humans could contribute to impair P. aeruginosa biofilm formation.}, } @article {pmid29124888, year = {2018}, author = {Liu, Y and Palmer, SR and Chang, H and Combs, AN and Burne, RA and Koo, H}, title = {Differential oxidative stress tolerance of Streptococcus mutans isolates affects competition in an ecological mixed-species biofilm model.}, journal = {Environmental microbiology reports}, volume = {10}, number = {1}, pages = {12-22}, pmid = {29124888}, issn = {1758-2229}, support = {T90 DE021990/DE/NIDCR NIH HHS/United States ; R01 DE013239/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025832/DE/NIDCR NIH HHS/United States ; K99 DE023833/DE/NIDCR NIH HHS/United States ; R00 DE023833/DE/NIDCR NIH HHS/United States ; }, mesh = {Actinomyces/physiology ; Biofilms/*growth & development ; Dental Caries/*microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Hydrogen Peroxide/metabolism/pharmacology ; Hydrogen-Ion Concentration ; *Microbial Interactions/physiology ; Multienzyme Complexes/genetics ; NADH, NADPH Oxidoreductases/genetics ; Oxidative Stress/*physiology ; Streptococcus mutans/pathogenicity/*physiology ; Streptococcus oralis/physiology ; Sucrose/metabolism ; Virulence/physiology ; }, abstract = {Streptococcus mutans strongly influences the development of pathogenic biofilms associated with dental caries. Our understanding of S. mutans behaviour in biofilms is based on a few well-characterized laboratory strains; however, individual isolates vary widely in genome content and virulence-associated phenotypes, such as biofilm formation and environmental stress sensitivity. Using an ecological biofilm model, we assessed the impact of co-cultivation of several S. mutans isolates with Streptococcus oralis and Actinomyces naeslundii on biofilm composition following exposure to sucrose. The laboratory reference strain S. mutans UA159 and clinical isolates Smu44 (most aciduric), Smu56 (altered biofilm formation) and Smu81 (more sensitive to oxidative stress) were used. Our data revealed S. mutans isolates varied in their ability to compete and become dominant in the biofilm after the addition of sucrose, and this difference correlated with sensitivity to H2 O2 produced by S. oralis. Smu81 was particularly sensitive to H2 O2 and could not compete with S. oralis in mixed-species biofilm, despite forming robust biofilms on its own. Thus, diminished oxidative stress tolerance in S. mutans isolates can impair their ability to compete in complex biofilms, even in the presence of sucrose, which could influence the progression of a healthy biofilm community to one capable of causing disease.}, } @article {pmid29121701, year = {2018}, author = {Hussain, M and Oh, DH}, title = {Impact of the Isolation Source on the Biofilm Formation Characteristics of Bacillus cereus.}, journal = {Journal of microbiology and biotechnology}, volume = {28}, number = {1}, pages = {77-86}, doi = {10.4014/jmb.1707.07023}, pmid = {29121701}, issn = {1738-8872}, mesh = {Bacillus cereus/*isolation & purification/*physiology ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Biopolymers/metabolism ; DNA, Bacterial/metabolism ; Environmental Microbiology ; Food Microbiology ; Foodborne Diseases/microbiology ; Humans ; Spores, Bacterial/growth & development ; }, abstract = {The human pathogen and food spoiler Bacillus cereus can form biofilms that act as a persistent source of contamination, which is of public health concern. This study aimed to understand how the source of isolation might affect the behavior of biofilm formation. Biofilm formation abilities of 56 strains of B. cereus isolated from different environments, including human food poisoning, farm, and food, were determined. Crystal violet assay results revealed significant (p < 0.05) differences in biofilm formation abilities among the strains isolated from different sources only at an early stage of incubation. However, strain origin showed no impact on later stage of biofilm formation. Next, correlation of the group of isolates on the basis of their biofilm-forming abilities with the number of sessile cells, sporulation, and extracellular polymeric substance (EPS) formation was determined. The number of sessile cells and spores in biofilms was greatly influenced by the groups of isolates that formed dense, moderate, and weak biofilms. The contribution of extracellular DNA and/or proteins to EPS formation was also positively correlated with biofilm formation abilities. Our results that the source of isolation had significant impact on biofilm formation might provide important information to develop strategies to control B. cereus biofilm formation.}, } @article {pmid29121106, year = {2017}, author = {Lei, MG and Gupta, RK and Lee, CY}, title = {Proteomics of Staphylococcus aureus biofilm matrix in a rat model of orthopedic implant-associated infection.}, journal = {PloS one}, volume = {12}, number = {11}, pages = {e0187981}, pmid = {29121106}, issn = {1932-6203}, support = {P20 GM103625/GM/NIGMS NIH HHS/United States ; R21 AI112028/AI/NIAID NIH HHS/United States ; S10 OD018445/OD/NIH HHS/United States ; }, mesh = {Animals ; Arthroplasty/*adverse effects ; Bacterial Proteins/*metabolism ; Biofilms ; Carrier Proteins/metabolism ; Disease Models, Animal ; Leukocidins/metabolism ; Membrane Proteins/metabolism ; Proteomics/*methods ; Rats ; Staphylococcal Infections/etiology/*microbiology ; Staphylococcus aureus/metabolism/*physiology ; }, abstract = {The matrix proteins of Staphylococcus aureus biofilm have not been well defined. Previous efforts to identify these proteins were performed using in vitro systems. Here we use a proteomic approach to identify biofilm matrix proteins directly from infected bone implants using a rat model of orthopedic implant-associated S. aureus infection. Despite heavy presence of host proteins, a total of 28 and 105 S. aureus proteins were identified during acute infection and chronic infection, respectively. Our results show that biofilm matrix contains mostly intracellular cytoplasmic proteins and, to a much less extent, extracellular and cell surface-associated proteins. Significantly, leukocidins were identified in the biofilm matrix during chronic infection, suggesting S. aureus is actively attacking the host immune system even though they are protected within the biofilm. The presence of two surface-associated proteins, Ebh and SasF, in the infected bone tissue during acute infection was confirmed by immunohistochemistry. In addition, a large number of host proteins were found differentially expressed in response to S. aureus biofilm formed on bone implants.}, } @article {pmid29120888, year = {2017}, author = {Yamada, J and Takiguchi, T and Saito, A and Odanaka, H and Soyama, H and Yamamoto, M}, title = {Removal of Oral Biofilm on an Implant Fixture by a Cavitating Jet.}, journal = {Implant dentistry}, volume = {26}, number = {6}, pages = {904-910}, doi = {10.1097/ID.0000000000000681}, pmid = {29120888}, issn = {1538-2982}, mesh = {*Biofilms ; *Dental Devices, Home Care ; Dental Implants/*microbiology ; Dental Plaque/*microbiology ; Equipment Design ; Humans ; Oral Hygiene/*instrumentation ; Surface Properties ; Water ; }, abstract = {PURPOSE: To demonstrate the effectiveness of the cavitating jet in removing biofilms from the rough surface of 3-dimensional structures.

MATERIALS AND METHODS: The optimal nozzle dimensions and injection conditions were identified by cavitation impact measurements. Biofilm was grown intraorally for 72 hours by 4 volunteers. The stained fixtures were assigned to different experimental groups. One comparison was performed between the cavitating jet and the water jet at 60 seconds. Additional comparisons were conducted among the time course experiments at 30, 60, and 180 seconds. After injection, the residual plaque biofilm (RPB) area was measured using a digital microscope.

RESULTS: The total RPB of the cavitating jet was significantly lower than that of the water jet. Although there were no significant differences between the total RPB at 30 and 60 seconds, a significant difference was detected between 60 and 180 seconds. The RPB on the root sector was significantly lower than that on the crest sector at 60 and 180 seconds.

CONCLUSION: The cavitating jet can effectively clean the biofilm formed on the rough surface of the implant screw, especially on the root sector.}, } @article {pmid29119696, year = {2018}, author = {Nielsen, CK and Subbiahdoss, G and Zeng, G and Salmi, Z and Kjems, J and Mygind, T and Snabe, T and Meyer, RL}, title = {Antibacterial isoeugenol coating on stainless steel and polyethylene surfaces prevents biofilm growth.}, journal = {Journal of applied microbiology}, volume = {124}, number = {1}, pages = {179-187}, doi = {10.1111/jam.13634}, pmid = {29119696}, issn = {1365-2672}, mesh = {Adsorption ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Eugenol/*analogs & derivatives/chemistry/pharmacology ; Humans ; Listeria monocytogenes/drug effects/*physiology ; Polyethylene/*chemistry ; Pseudomonas fluorescens/drug effects/*physiology ; Stainless Steel/chemistry ; Staphylococcus aureus/drug effects/*physiology ; }, abstract = {AIMS: Pathogenic bacteria can spread between individuals or between food items via the surfaces they share. Limiting the survival of pathogens on surfaces, therefore, presents an opportunity to limit at least one route of how pathogens spread. In this study, we propose that a simple coating with the essential oil isoeugenol can be used to circumvent the problem of bacterial transfer via surfaces.

METHODS AND RESULTS: Two commonly used materials, stainless steel and polyethylene, were coated by physical adsorption, and the coatings were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurements. We quantified and visualized the colonization of coated and uncoated surfaces by three bacteria: Staphylococcus aureus, Listeria monocytogenes and Pseudomonas fluorescens. No viable cells were detected on surfaces coated with isoeugenol.

CONCLUSIONS: The isoeugenol coating prepared with simple adsorption proved effective in preventing biofilm formation on stainless steel and polyethylene surfaces. The result was caused by the antibacterial effect of isoeugenol, as the coating did not diminish the adhesive properties of the surface.

Our study demonstrates that a simple isoeugenol coating can prevent biofilm formation of S. aureus, L. monocytogenes and P. fluorescens on two commonly used surfaces.}, } @article {pmid29119430, year = {2018}, author = {Pires, DP and Melo, LDR}, title = {In Vitro Activity of Bacteriophages Against Planktonic and Biofilm Populations Assessed by Flow Cytometry.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1693}, number = {}, pages = {33-41}, doi = {10.1007/978-1-4939-7395-8_4}, pmid = {29119430}, issn = {1940-6029}, mesh = {Bacteria/*virology ; *Bacterial Physiological Phenomena ; Bacteriophages/*physiology ; Biofilms/*growth & development ; Flow Cytometry/*methods ; Plankton/*growth & development/virology ; }, abstract = {The in vitro activity of bacteriophages against planktonic cultures and biofilms is commonly evaluated by culture methods. However, these methods can lead to an underestimation of total bacterial cells when they undergo different physiological states.This chapter describes the methodology used to assess the in vitro activity of bacteriophages against planktonic cultures of bacteria in different metabolic states and biofilm populations by flow cytometry.}, } @article {pmid29119323, year = {2018}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Optimization of Bacillus subtilis natto growth parameters in glycerol-based medium for vitamin K (Menaquinone-7) production in biofilm reactors.}, journal = {Bioprocess and biosystems engineering}, volume = {41}, number = {2}, pages = {195-204}, doi = {10.1007/s00449-017-1857-0}, pmid = {29119323}, issn = {1615-7605}, mesh = {Bacillus subtilis/*growth & development ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Culture Media/*pharmacology ; Glycerol/*pharmacology ; Vitamin K 2/*analogs & derivatives/metabolism ; }, abstract = {Menaquinone-7 (MK-7) is the key form of vitamin K used as a dietary supplement and its production revolves around Bacillus subtilis natto. Current fermentation strategies, which suggest static fermentations without aeration and agitation, can be problematic for large scale MK-7 production due to biofilm formation. The use of biofilm reactors, therefore, is proposed in the present study, which could utilize both agitation and aeration without interrupting MK-7 secretion. In this study, biofilm reactors were constructed using the selected plastic composite support (PCS) and B. subtilis natto strain for MK-7 production. Using response surface methodology (RSM), optimum growth parameters including temperature, pH, and agitation were determined in a glycerol-based medium. Results were presented in a statistical model (R [2] = 0.90), leading to optimum growth conditions of temperature (35 °C), agitation (200 rpm) and pH (6.58). Model-predicted MK-7 concentration was validated and MK-7 concentration of 12.09 mg/L was produced in the biofilm reactor. The obtained concentration was 58% higher as compared to the suspended-cell culture (7.67 mg/L). The results of this study will provide a critical step towards improved industrial scale production of MK-7.}, } @article {pmid29118745, year = {2017}, author = {Soavelomandroso, AP and Gaudin, F and Hoys, S and Nicolas, V and Vedantam, G and Janoir, C and Bouttier, S}, title = {Biofilm Structures in a Mono-Associated Mouse Model of Clostridium difficile Infection.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2086}, pmid = {29118745}, issn = {1664-302X}, support = {I01 BX001183/BX/BLRD VA/United States ; }, abstract = {Clostridium difficile infection (CDI) is a major healthcare-associated disease with high recurrence rates. Host colonization is critical for the infectious process, both in first episodes and in recurrent disease, with biofilm formation playing a key role. The ability of C. difficile to form a biofilm on abiotic surfaces is established, but has not yet been confirmed in the intestinal tract. Here, four different isolates of C. difficile, which are in vitro biofilm producers, were studied for their ability to colonize germ-free mice. The level of colonization achieved was similar for all isolates in the different parts of the murine gastrointestinal tract, but pathogen burden was higher in the cecum and colon. Confocal laser scanning microscopy revealed that C. difficile bacteria were distributed heterogeneously over the intestinal tissue, without contact with epithelial cells. The R20291 strain, which belongs to the Ribotype 027 lineage, displayed a unique behavior compared to the other strains by forming numerous aggregates. By immunochemistry analyses, we showed that bacteria were localized inside and outside the mucus layer, irrespective of the strains tested. Most bacteria were entrapped in 3-D structures overlaying the mucus layer. For the R20291 strain, the cell-wall associated polysaccharide PS-II was detected in large amounts in the 3-D structure. As this component has been detected in the extrapolymeric matrix of in vitro C. difficile biofilms, our data suggest strongly that at least the R20291 strain is organized in the mono-associated mouse model in glycan-rich biofilm architecture, which sustainably maintains bacteria outside the mucus layer.}, } @article {pmid29117591, year = {2018}, author = {Zhai, S and Ji, M and Zhao, Y and Pavlostathis, SG and Zhao, Q}, title = {Effects of salinity and COD/N on denitrification and bacterial community in dicyclic-type electrode based biofilm reactor.}, journal = {Chemosphere}, volume = {192}, number = {}, pages = {328-336}, doi = {10.1016/j.chemosphere.2017.10.108}, pmid = {29117591}, issn = {1879-1298}, mesh = {Autotrophic Processes ; *Biofilms ; Bioreactors/*microbiology/standards ; *Denitrification ; Heterotrophic Processes ; Nitrates/isolation & purification ; Nitrogen/analysis ; *Salinity ; Sewage/microbiology ; Wastewater/chemistry ; Water Purification/methods ; }, abstract = {A dicyclic-type electrode based biofilm electrode reactor (BER) was developed for advanced nitrate removal from saline municipal wastewater. The denitrification efficiency was evaluated with a synthetic feed (NO3[-]-N, 20 mg L[-1]) under different salinity and COD to nitrogen ratios (COD/N). As the salinity increased from 0% to 1.0%, the denitrification performance of both the traditional biofilm reactor (BR) and BER was inhibited; however, the BER showed better adaptation and ability to recover. The BER achieved a high nitrate removal efficiency (≥90%) at a salinity of 1.0% and a low COD/N of 2.5 (theoretical stoichiometric 2.86 ignoring microbial growth). The abundance of Methylotenera mobilis in BR and Clostridium sticklandii in BER was higher than in the initial sludge sample used as inoculum. Likewise, the abundance of napA, nirS and nosZ genes increased as the COD/N further decreased. Under high salinity stress, the BER had a higher denitrification efficiency and the consumption of the organic carbon source (i.e., methanol) was reduced compared to BR. The cooperation between heterotrophic and autotrophic denitrifiers in the BER system provides a more efficient and feasible solution for nitrate removal from saline municipal wastewater.}, } @article {pmid29116300, year = {2017}, author = {Oliveira, MAC and Borges, AC and Brighenti, FL and Salvador, MJ and Gontijo, AVL and Koga-Ito, CY}, title = {Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity.}, journal = {Brazilian oral research}, volume = {31}, number = {}, pages = {e89}, doi = {10.1590/1807-3107BOR-2017.vol31.0089}, pmid = {29116300}, issn = {1807-3107}, mesh = {Actinomyces/drug effects/growth & development ; Analysis of Variance ; Anti-Infective Agents/*pharmacology ; Anti-Infective Agents, Local/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Cell Survival/drug effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Colony Count, Microbial ; Cymbopogon/*chemistry ; Dental Caries/*microbiology/*prevention & control ; Dental Enamel/drug effects/microbiology ; Gas Chromatography-Mass Spectrometry ; Humans ; Keratinocytes/drug effects ; Lactobacillus acidophilus/drug effects/growth & development ; Microbial Sensitivity Tests ; Oils, Volatile/*pharmacology ; Reference Values ; Reproducibility of Results ; Statistics, Nonparametric ; Streptococcus/drug effects/growth & development ; Time Factors ; }, abstract = {The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.}, } @article {pmid29115611, year = {2018}, author = {Hasibul, K and Nakayama-Imaohji, H and Hashimoto, M and Yamasaki, H and Ogawa, T and Waki, J and Tada, A and Yoneda, S and Tokuda, M and Miyake, M and Kuwahara, T}, title = {D‑Tagatose inhibits the growth and biofilm formation of Streptococcus mutans.}, journal = {Molecular medicine reports}, volume = {17}, number = {1}, pages = {843-851}, pmid = {29115611}, issn = {1791-3004}, mesh = {Biofilms/*drug effects ; Carbohydrate Metabolism/drug effects/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Gene Expression Regulation, Enzymologic ; Hexoses/metabolism/*pharmacology ; Streptococcus mutans/*drug effects/genetics/*growth & development/metabolism ; }, abstract = {Dental caries is an important global health concern and Streptococcus mutans has been established as a major cariogenic bacterial species. Reports indicate that a rare sugar, D‑tagatose, is not easily catabolized by pathogenic bacteria. In the present study, the inhibitory effects of D‑tagatose on the growth and biofilm formation of S. mutans GS‑5 were examined. Monitoring S. mutans growth over a 24 h period revealed that D‑tagatose prolonged the lag phase without interfering with the final cell yield. This growth retardation was also observed in the presence of 1% sucrose, although it was abolished by the addition of D‑fructose. S. mutans biofilm formation was significantly inhibited by growth in sucrose media supplemented with 1 and 4% D‑tagatose compared with that in a culture containing sucrose alone, while S. mutans formed granular biofilms in the presence of this rare sugar. The inhibitory effect of D‑tagatose on S. mutans biofilm formation was significantly more evident than that of xylitol. Growth in sucrose media supplemented with D‑tagatose significantly decreased the expression of glucosyltransferase, exo‑β‑fructosidase and D‑fructose‑specific phosphotransferase genes but not the expression of fructosyltransferase compared with the culture containing sucrose only. The activity of cell‑associated glucosyltransferase in S. mutans was inhibited by 4% D‑tagatose. These results indicate that D‑tagatose reduces water‑insoluble glucan production from sucrose by inhibiting glucosyltransferase activities, which limits access to the free D‑fructose released during this process and retards the growth of S. mutans. Therefore, foods and oral care products containing D‑tagatose are anticipated to reduce the risk of caries by inhibiting S. mutans biofilm formation.}, } @article {pmid29114981, year = {2018}, author = {Zhang, S and Chen, Y and Ma, Z and Chen, Q and Ostapska, H and Gravelat, FN and Lu, L and Sheppard, DC}, title = {PtaB, a lim-domain binding protein in Aspergillus fumigatus regulates biofilm formation and conidiation through distinct pathways.}, journal = {Cellular microbiology}, volume = {20}, number = {1}, pages = {}, doi = {10.1111/cmi.12799}, pmid = {29114981}, issn = {1462-5822}, support = {123306//CIHR/Canada ; 81361//CIHR/Canada ; }, mesh = {Aspergillosis/microbiology/pathology ; Aspergillus fumigatus/genetics/*growth & development/pathogenicity ; Biofilms/*growth & development ; Cell Adhesion/genetics ; Fungal Proteins/*metabolism ; Gene Expression Regulation, Fungal/*genetics ; Gene Knockout Techniques ; Polysaccharides/*biosynthesis/genetics ; Spores, Fungal/*growth & development ; Transcription Factors/metabolism ; }, abstract = {The exopolysaccharide galactosaminogalactan (GAG) plays an important role in mediating adhesion, biofilm formation, and virulence in the pathogenic fungus Aspergillus fumigatus. The developmental modifiers MedA, StuA, and SomA regulate GAG biosynthesis, but the mechanisms underlying this regulation are poorly understood. PtaB is a lim-domain binding protein that interacts with the transcription factor SomA and is required for normal conidiation and biofilm formation. Disruption of ptaB resulted in impaired GAG production and conidiation in association with a markedly reduced expression of GAG biosynthetic genes (uge3 and agd3), developmental regulators (medA and stuA), and genes involved in the core conidiation pathway. Overexpression of medA and dual overexpression of uge3 and agd3 in the ΔptaB mutant increased biofilm formation but not conidiation, whereas overexpression of core conidiation genes rescued conidiation but not biofilm formation. Overexpression of stuA modestly increased both conidiation and biofilm formation. Analysis of ptaB truncation mutants revealed that overexpression of the lim-domain binding region restored conidiation but not biofilm formation, suggesting that ptaB may govern these processes by interacting with different partners. These studies establish that PtaB governs GAG biosynthesis at the level of substrate availability and polymer deacetylation and that PtaB-mediated biofilm formation and conidiation are largely independent pathways.}, } @article {pmid29112725, year = {2017}, author = {Chandra, K and Garai, P and Chatterjee, J and Chakravortty, D}, title = {Peptide transporter YjiY influences the expression of the virulence gene mgtC to regulate biofilm formation in Salmonella.}, journal = {FEMS microbiology letters}, volume = {364}, number = {24}, pages = {}, doi = {10.1093/femsle/fnx236}, pmid = {29112725}, issn = {1574-6968}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cation Transport Proteins/*genetics ; Gene Expression Regulation, Bacterial/*genetics ; Membrane Transport Proteins/*metabolism ; Salmonella typhimurium/genetics/*physiology ; }, abstract = {Formation of a biofilm is one of the coping strategies of Salmonella against antimicrobial environmental stresses including nutrient starvation. However, the channeling of the starvation cue towards biofilm formation is not well understood. Our study shows that a carbon starvation gene, yjiY, coding for a peptide transporter, influences the expression of a virulence-associated gene mgtC in Salmonella to regulate biofilm formation. We demonstrate here that the mutant strain ΔyjiY is unable to form a biofilm due to the increased expression of mgtC. The upregulation of mgtC in the ΔyjiY strain correlates with the downregulation of the biofilm master regulator gene, csgD, and reduced levels of ATP. Our work further indicates that a yjiY-encoded peptide transporter may regulate the expression of mgtC by transporting proline peptides.}, } @article {pmid29112170, year = {2017}, author = {Wu, X and Pan, J and Wu, Y and Xi, X and Ma, C and Wang, L and Zhou, M and Chen, T}, title = {PSN-PC: A Novel Antimicrobial and Anti-Biofilm Peptide from the Skin Secretion of Phyllomedusa-camba with Cytotoxicity on Human Lung Cancer Cell.}, journal = {Molecules (Basel, Switzerland)}, volume = {22}, number = {11}, pages = {}, pmid = {29112170}, issn = {1420-3049}, mesh = {Antimicrobial Cationic Peptides/isolation & purification/*pharmacology ; Antineoplastic Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Carcinoma, Non-Small-Cell Lung/*drug therapy ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Drug Screening Assays, Antitumor ; Escherichia coli/drug effects ; Humans ; Lung Neoplasms/*drug therapy ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; }, abstract = {Peptides derived from amphibian skin secretion are promising drug prototypes for combating widespread infection. In this study, a novel peptide belonging to the phylloseptin family of antimicrobial peptides was isolated from the skin secretion of the Phyllomedusa camba, namely phylloseptin-PC (PSN-PC). The biosynthetic precursor was obtained by molecular cloning and the mature peptide sequence was confirmed through tandem mass spectrometry (MS/MS) fragmentation sequencing in the skin secretion. The synthetic replicate exhibited a broad spectrum antimicrobial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus,Escherichia coli, Pseudomonas aeruginosa, Candida albicans at concentrations of 2, 2, 8, 32 and 2 µM, respectively. It also showed the capability of eliminating S. aureus biofilm with a minimal biofilm eradication concentration of 8 µM. The haemolysis of this peptide was not significant at low concentrations but had a considerable increase at high concentrations. Additionally, this peptide showed an anti-proliferation effect on the non-small cell lung cancer cell line (NCI-H157), with low cytotoxicity on the human microvascular endothelial cell line (HMEC-1). The discovery of the novel peptide may provide useful clues for new drug discoveries.}, } @article {pmid29111401, year = {2018}, author = {Guembe, M and Alonso, B and Lucio, J and Pérez-Granda, MJ and Cruces, R and Sánchez-Carrillo, C and Fernández-Cruz, A and Bouza, E}, title = {Biofilm production is not associated with poor clinical outcome in 485 patients with Staphylococcus aureus bacteraemia.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {24}, number = {6}, pages = {659.e1-659.e3}, doi = {10.1016/j.cmi.2017.10.018}, pmid = {29111401}, issn = {1469-0691}, mesh = {Adolescent ; Bacteremia/*microbiology ; Biofilms ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Methicillin-Resistant Staphylococcus aureus/classification/isolation & purification/physiology ; Prognosis ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/classification/isolation & purification/*physiology ; }, abstract = {OBJECTIVES: Staphylococcus aureus biofilm may constitute a major cause of virulence. Our main objective was to analyse whether there was an association between biofilm production and poor outcome in patients with S. aureus bacteraemia.

METHODS: We studied 485 S. aureus strains isolated from the blood of patients with bacteraemia from 2012 to 2015. We assessed in vitro biomass production using crystal violet assay and metabolic activity using tetrazolium salt assay. Strains were classified in tertile ranks as follows: low biomass producers, moderate biomass producers, high biomass producers, low metabolic activity, moderate metabolic activity and high metabolic activity. We excluded from analysis strains with moderate crystal violet and tetrazolium salt values. We defined poor outcome as fulfillment of one or more of the following conditions: 30-day attributable mortality, infective endocarditis, persistent bacteraemia and recurrent bacteraemia.

RESULTS: Outcome was poor in 199 (41.0%) of 485 S. aureus bacteraemia episodes. The distribution of poor outcome with respect to biomass production and metabolic activity was as follows: low biomass producers, 36.6% vs. high biomass producers, 43.2% (p 0.26); and low metabolic activity, 43.5% vs. high metabolic activity, 36.2% (p 0.91). The presence of methicillin-resistant S. aureus was the only characteristic that was more likely to be present in the high metabolic activity group (17.4% vs. 39.3%, p < 0.001).

CONCLUSIONS: Biofilm production, as determined by any of the methods used in the present study, is not associated with poor outcome in patients with S. aureus bacteraemia.}, } @article {pmid29111400, year = {2018}, author = {Waller, SA and Packman, AI and Hausner, M}, title = {Comparison of biofilm cell quantification methods for drinking water distribution systems.}, journal = {Journal of microbiological methods}, volume = {144}, number = {}, pages = {8-21}, doi = {10.1016/j.mimet.2017.10.013}, pmid = {29111400}, issn = {1872-8359}, mesh = {Bacteriological Techniques/methods ; *Biofilms/growth & development ; Colony Count, Microbial ; Drinking Water/*microbiology ; Flow Cytometry/methods ; Materials Testing ; Microbial Viability ; Microscopy, Confocal/*methods ; *Water Microbiology ; *Water Quality ; Water Supply ; }, abstract = {Drinking water quality typically degrades after treatment during conveyance through the distribution system. Potential causes include biofilm growth in distribution pipes which may result in pathogen retention, inhibited disinfectant diffusion, and proliferation of bad tastes and odors. However, there is no standard method for direct measurement of biofilms or quantification of biofilm cells in drinking water distribution systems. Three methods are compared here for quantification of biofilm cells grown in pipe loops samplers: biofilm heterotrophic plate count (HPC), biofilm biovolume by confocal laser scanning microscopy (CLSM) and biofilm total cell count by flow cytometry (FCM) paired with Syto 9. Both biofilm biovolume by CLSM and biofilm total cell count by FCM were evaluated for quantification of the whole biofilms (including non-viable cells and viable but not culturable cells). Signal-to-background ratios and overall performance of biofilm biovolume by CLSM and biofilm total cell count by FCM were found to vary with the pipe material. Biofilm total cell count by FCM had a low signal-to-background ratio on all materials, indicating that further development is recommended before application in drinking water environments. Biofilm biovolume by CLSM showed the highest signal-to-background ratio for cement and cast iron, which suggests promise for wider application in full-scale systems. Biofilm biovolume by CLSM and Syto 9 staining allowed in-situ biofilm cell quantification thus elimination variable associated with cell detachment for quantification but had limitations associated with non-specific staining of cement and, to a lesser degree, auto-fluorescence of both cement and polyvinyl chloride materials. Due to variability in results obtained from each method, multiple methods are recommended to assess biofilm growth in drinking water distribution systems. Of the methods investigated here, HPC and CLSM and recommended for further development towards application in full-scale systems. HPC is a sample and widely applied method that quantifies viable culturable cells. CLSM analysis allows the elimination of experimental variables associated with cell detachment and affords the opportunity to evaluate biofilm components such as extracellular polymeric substances through the addition of specific probes. These two methods can be applied together to assess biofilms known to degrade treated water quality during conveyance in full-scale drinking water treatment systems. The significance of improved biofilm assessment methods for drinking water distribution systems lies in advancing understanding of biofilm growth and control mechanisms that may lead to improved water quality during conveyance and at the tap for greater public health protection.}, } @article {pmid29109817, year = {2017}, author = {Richard, C and Mitbavkar, S and Landoulsi, J}, title = {Diagnosis of the Diatom Community upon Biofilm Development on Stainless Steels in Natural Freshwater.}, journal = {Scanning}, volume = {2017}, number = {}, pages = {5052646}, pmid = {29109817}, issn = {1932-8745}, mesh = {Biofilms/*growth & development ; *Biota ; Diatoms/*classification/cytology/*isolation & purification/physiology ; Fresh Water/*microbiology ; Microscopy, Electron, Scanning ; Stainless Steel ; }, abstract = {This paper reports the development of biofilms on stainless steels (SS) upon exposure in a natural freshwater ecosystem for about six months and focuses on the composition of diatom populations. By using environmental scanning electron microscopy (ESEM) technique, we provide a detailed description regarding diatom identification at species level as well as their main characteristics, including type, morphology, ability to form colony, and motility. Results reveal the presence of both prostrate (initial colonizers) and stalked (late colonizers) forms. Pennate diatoms, Cocconeis placentula and Amphora coffeaeformis, and a centric diatom, Melosira varians, are shown to be the abundant forms regardless of the SS type. Pennate diatoms dominate the community and are directly attached to the substratum, whereas the centric form is entangled in the biofilm matrix in a significant number. The dominance of adnate forms suggests that these cells are sturdy and successfully maintaining their population. In situ monitoring of the electrochemical response of immersed materials showed ennoblement of the open circuit potential, which seems to be due to the biogenic production of H2O2, detected in a significant amount within the biofilms. The substantial enrichment of biofilms with diatoms potentially suggests the implication of these microorganisms in the process of ennoblement. A mechanism is proposed in this paper describing the possible interactions of diatom community with SS in the studied ecosystem.}, } @article {pmid29109808, year = {2017}, author = {Gomes, LC and Mergulhão, FJ}, title = {SEM Analysis of Surface Impact on Biofilm Antibiotic Treatment.}, journal = {Scanning}, volume = {2017}, number = {}, pages = {2960194}, pmid = {29109808}, issn = {1932-8745}, mesh = {Ampicillin/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Environmental Microbiology ; Escherichia coli/*drug effects/*physiology ; Glass ; Microbial Viability/drug effects ; *Microscopy, Electron, Scanning ; Silicones ; Surface Properties/*drug effects ; }, abstract = {The aim of this work was to use scanning electron microscopy (SEM) to investigate the effect of ampicillin treatment on Escherichia coli biofilms formed on two surface materials with different properties, silicone (SIL) and glass (GLA). Epifluorescence microscopy (EM) was initially used to assess biofilm formation and killing efficiency on both surfaces. This technique showed that higher bacterial colonization was obtained in the hydrophobic SIL than in the hydrophilic GLA. It has also shown that higher biofilm inactivation was attained for GLA after the antibiotic treatment (7-log reduction versus 1-log reduction for SIL). Due to its high resolution and magnification, SEM enabled a more detailed analysis of the antibiotic effect on biofilm cells, complementing the killing efficiency information obtained by EM. SEM micrographs revealed that ampicillin-treated cells have an elongated form when compared to untreated cells. Additionally, it has shown that different materials induced different levels of elongation on cells exposed to antibiotic. Biofilms formed on GLA showed a 37% higher elongation than those formed on SIL. Importantly, cell elongation was related to viability since ampicillin had a higher bactericidal effect on GLA-formed biofilms. These findings raise the possibility of using SEM for understanding the efficacy of antimicrobial treatments by observation of biofilm morphology.}, } @article {pmid29109186, year = {2018}, author = {Liu, C and Liew, CW and Wong, YH and Tan, ST and Poh, WH and Manimekalai, MSS and Rajan, S and Xin, L and Liang, ZX and Grüber, G and Rice, SA and Lescar, J}, title = {Insights into Biofilm Dispersal Regulation from the Crystal Structure of the PAS-GGDEF-EAL Region of RbdA from Pseudomonas aeruginosa.}, journal = {Journal of bacteriology}, volume = {200}, number = {3}, pages = {}, pmid = {29109186}, issn = {1098-5530}, mesh = {Amino Acid Sequence ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cloning, Molecular ; Crystallography ; Models, Molecular ; Protein Conformation ; Protein Domains ; Pseudomonas aeruginosa/genetics/*metabolism ; }, abstract = {RbdA is a positive regulator of biofilm dispersal of Pseudomonas aeruginosa Its cytoplasmic region (cRbdA) comprises an N-terminal Per-ARNT-Sim (PAS) domain followed by a diguanylate cyclase (GGDEF) domain and an EAL domain, whose phosphodiesterase activity is allosterically stimulated by GTP binding to the GGDEF domain. We report crystal structures of cRbdA and of two binary complexes: one with GTP/Mg[2+] bound to the GGDEF active site and one with the EAL domain bound to the c-di-GMP substrate. These structures unveil a 2-fold symmetric dimer stabilized by a closely packed N-terminal PAS domain and a noncanonical EAL dimer. The autoinhibitory switch is formed by an α-helix (S-helix) immediately N-terminal to the GGDEF domain that interacts with the EAL dimerization helix (α6-E) of the other EAL monomer and maintains the protein in a locked conformation. We propose that local conformational changes in cRbdA upon GTP binding lead to a structure with the PAS domain and S-helix shifted away from the GGDEF-EAL domains, as suggested by small-angle X-ray scattering (SAXS) experiments. Domain reorientation should be facilitated by the presence of an α-helical lever (H-helix) that tethers the GGDEF and EAL regions, allowing the EAL domain to rearrange into an active dimeric conformation.IMPORTANCE Biofilm formation by bacterial pathogens increases resistance to antibiotics. RbdA positively regulates biofilm dispersal of Pseudomonas aeruginosa The crystal structures of the cytoplasmic region of the RbdA protein presented here reveal that two evolutionarily conserved helices play an important role in regulating the activity of RbdA, with implications for other GGDEF-EAL dual domains that are abundant in the proteomes of several bacterial pathogens. Thus, this work may assist in the development of small molecules that promote bacterial biofilm dispersal.}, } @article {pmid29107946, year = {2017}, author = {Jung, SI and Rodriguez, N and Irrizary, J and Liboro, K and Bogarin, T and Macias, M and Eivers, E and Porter, E and Filler, SG and Park, H}, title = {Yeast casein kinase 2 governs morphology, biofilm formation, cell wall integrity, and host cell damage of Candida albicans.}, journal = {PloS one}, volume = {12}, number = {11}, pages = {e0187721}, pmid = {29107946}, issn = {1932-6203}, support = {R01 DE026600/DE/NIDCR NIH HHS/United States ; SC3 GM103699/GM/NIGMS NIH HHS/United States ; R25 GM061331/GM/NIGMS NIH HHS/United States ; SC1 GM096916/GM/NIGMS NIH HHS/United States ; R01 AI124566/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Candida albicans/*enzymology/growth & development ; Casein Kinase II/*metabolism ; *Cell Wall ; Chitin/biosynthesis ; Real-Time Polymerase Chain Reaction ; }, abstract = {The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions.}, } @article {pmid29104975, year = {2017}, author = {Im, H and Lee, S and Soper, SA and Mitchell, RJ}, title = {Staphylococcus aureus extracellular vesicles (EVs): surface-binding antagonists of biofilm formation.}, journal = {Molecular bioSystems}, volume = {13}, number = {12}, pages = {2704-2714}, pmid = {29104975}, issn = {1742-2051}, support = {P41 EB020594/EB/NIBIB NIH HHS/United States ; }, mesh = {Acinetobacter baumannii/drug effects ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Bleaching Agents/pharmacology ; Edetic Acid/pharmacology ; Hydrophobic and Hydrophilic Interactions ; Polystyrenes/chemistry ; Staphylococcus aureus/*drug effects ; }, abstract = {The prevalence of Staphylococcus aureus worldwide as a nosocomial infectious agent is recognized but the reason behind the spread of this bacterium has remained elusive. Here, we hypothesized that the communication of S. aureus might benefit from it blocking other bacteria from establishing themselves on the surface. This was found to be the case for several pathogens as the S. aureus supernatant curtailed their ability to form biofilms. Subsequent analyses using Acinetobacter baumannii as a model found this effect is primarily mediated by S. aureus' extracellular vesicles (EVs), which bound to the polystyrene surface. We found the EV-treated surfaces were significantly more hydrophilic after EV treatment, a condition that made it difficult for A. baumannii to initially adhere to the polystyrene surface and reduced its resulting biofilm by up to 93%. Subsequent tests found this also extended to several other bacterial pathogens, with a 40-70% decrease in their biofilm mass. The S. aureus EVs and their activity still remained after the surface was washed with 10% bleach, while the use of ethylenediaminetetraacetic acid (EDTA) removed both the EVs from the surface and their activity.}, } @article {pmid29104645, year = {2017}, author = {Chanda, W and Joseph, TP and Padhiar, AA and Guo, X and Min, L and Wang, W and Lolokote, S and Ning, A and Cao, J and Huang, M and Zhong, M}, title = {Combined effect of linolenic acid and tobramycin on Pseudomonas aeruginosa biofilm formation and quorum sensing.}, journal = {Experimental and therapeutic medicine}, volume = {14}, number = {5}, pages = {4328-4338}, pmid = {29104645}, issn = {1792-0981}, abstract = {Pseudomonas aeruginosa is a ubiquitous Gram negative opportunistic pathogen capable of causing severe nosocomial infections in humans, and tobramycin is currently used to treat P. aeruginosa associated lung infections. Quorum sensing regulates biofilm formation which allows the bacterium to result in fatal infections forcing clinicians to extensively use antibiotics to manage its infections leading to emerging multiple drug resistant strains. As a result, tobramycin is also becoming resistant. Despite extensive studies on drug discovery to alleviate microbial drug resistance, the continued microbial evolution has forced researchers to focus on screening various phytochemicals and dietary compounds for antimicrobial potential. Linolenic acid (LNA) is an essential fatty acid that possesses antimicrobial actions on various microorganisms. It was hypothesized that LNA may affect the formation of biofilm on P. aeruginosa and improve the potency of tobramycin. The present study demonstrated that LNA interfered with cell-to-cell communication and reduced virulence factor production. It further enhanced the potency of tobramycin and synergistically inhibited biofilm formation through P. aeruginosa quorum sensing systems. Therefore, LNA may be considered as a potential agent for adjunctive therapy and its utilization may decrease tobramycin concentration in combined treatment thereby reducing aminoglycoside adverse effects.}, } @article {pmid29104052, year = {2018}, author = {Tan, Y and Ma, S and Leonhard, M and Moser, D and Schneider-Stickler, B}, title = {β-1,3-glucanase disrupts biofilm formation and increases antifungal susceptibility of Candida albicans DAY185.}, journal = {International journal of biological macromolecules}, volume = {108}, number = {}, pages = {942-946}, doi = {10.1016/j.ijbiomac.2017.11.003}, pmid = {29104052}, issn = {1879-0003}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/*physiology/ultrastructure ; *Drug Resistance, Fungal ; Glucan 1,3-beta-Glucosidase/genetics/*metabolism ; Microbial Sensitivity Tests ; Phenotype ; }, abstract = {β-1,3-glucan plays a role in Candida biofilm formation and survival of biofilm-forming Candida to stresses. In this study, we evaluated the antibiofilm activity of β-1,3-glucanase, which can degrade poly-β(1→3)-glucose of Candida albicans biofilms. Biofilm was dispersed by 55.96%. β-1,3-glucanase had no effect on Candida planktonic growth as well as adhesion. β-1,3-glucanase markedly enhanced the antifungal susceptibility of fluconazole and amphotericin B. The examination using confocal laser scanning microscopy and scanning electron microscope confirmed the antibiofilm activity of β-1,3-glucanase. Our findings demonstrate that β-1,3-glucanase may be useful as an antibiofilm agent.}, } @article {pmid29103718, year = {2018}, author = {Marka, S and Anand, S}, title = {Feed substrates influence biofilm formation on reverse osmosis membranes and their cleaning efficiency.}, journal = {Journal of dairy science}, volume = {101}, number = {1}, pages = {84-95}, doi = {10.3168/jds.2017-13249}, pmid = {29103718}, issn = {1525-3198}, mesh = {Animals ; Bacteria/chemistry/*isolation & purification ; *Biofilms ; Cattle ; Membranes, Artificial ; Milk/chemistry/microbiology ; Osmosis ; Ultrafiltration/instrumentation/*methods ; }, abstract = {The dairy industry is increasingly using reverse osmosis (RO) membranes for concentration of various fluid feed materials such as whey and ultrafiltration (UF) permeate. This study compared the effect of UF permeate and whey on membrane biofilm formation. A Bacillus sp., previously isolated in our laboratory from a cleaning-resistant membrane biofilm, was used to develop 48-h-old static biofilms on RO membrane pieces, using the different feed substrates (UF permeate, whey, and an alternating whey/UF feed). Biofilms were analyzed for viable counts by the swab technique, and we used scanning electron and atomic force microscopy for microstructure imaging. The membrane cleaning process included 6 sequential steps. We observed differences in the resistance pattern of the 3 types of biofilms to the typical cleaning process. The mean pretreatment counts of the 48-h UF permeate biofilms were 5.39 log cfu/cm[2], much higher than the whey biofilm counts of 3.44 log, and alternating whey/UF biofilm counts of 4.54 log. After a 6-step cleaning cycle, we found 2.54 log survivors of the Bacillus isolate on UF biofilms, whereas only 1.82 log survivors were found in whey biofilm, and 2.14 log survivors on whey/UF permeate biofilms. In conclusion, the UF permeate biofilms was more resistant to the biofilm cleaning process compared with the whey or whey/UF permeate biofilms. Scanning electron micrographs showed different microstructures of biofilms based on the type of feed. For UF permeate and whey/UF permeate biofilms, bacilli were present in multilayers of cells in aggregates or irregular clusters with foulant layers. In contrast, those in whey biofilms were in monolayers, with a smoother, flatter appearance. Atomic force microscopy analysis indicated that UF permeate biofilms had the greatest surface roughness among the biofilms, reflecting intensified bacterial colonization. The biofilm micro- and nanostructure variations for the 2 feed substrates and their combination may have resulted in differences in their resistance to the cleaning process.}, } @article {pmid29103118, year = {2018}, author = {Ding, Y and Lyu, T and Bai, S and Li, Z and Ding, H and You, S and Xie, Q}, title = {Effect of multilayer substrate configuration in horizontal subsurface flow constructed wetlands: assessment of treatment performance, biofilm development, and solids accumulation.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {2}, pages = {1883-1891}, pmid = {29103118}, issn = {1614-7499}, support = {51408147//National Natural Science Foundation of China/ ; 41404116//National Natural Science Foundation of China/ ; 51638006//National Natural Science Foundation of China/ ; Guikehe1599005-2-2//Science research and technology development project of Guangxi/ ; KH2012ZD004//Guangxi Scientific Experiment Center of Mining, Metallurgy and Environment/ ; 002401013001//high level innovation team and standing scholar in Guangxi colleges and universities/ ; }, mesh = {Biofilms/*growth & development ; China ; Pilot Projects ; Principal Component Analysis ; Sewage/*analysis ; Solid Waste/*analysis ; Surface Properties ; Waste Disposal, Fluid/*methods ; *Wetlands ; }, abstract = {This study investigates the influence of multilayer substrate configuration in horizontal subsurface flow constructed wetlands (HSCWs) on their treatment performance, biofilm development, and solids accumulation. Three pilot-scale HSCWs were built to treat campus sewage and have been operational for 3 years. The HSCWs included monolayer (CW1), three-layer (CW3), and six-layer (CW6) substrate configurations with hydraulic conductivity of the substrate increasing from the surface to bottom in the multilayer CWs. It was demonstrated the pollutant removal performance after a 3-year operation improved in the multilayer HSCWs (49-80%) compared to the monolayer HSCW (29-41%). Simultaneously, the multilayer HSCWs exhibited significant features that prevented clogging compared to the monolayer configuration. The amount of accumulated solids was notably higher in the monolayer CW compared to multilayer CWs. Further, multilayer HSCWs could delay clogging by providing higher biofilm development for organics removal and consequently, lesser solids accumulations. Principal component analysis strongly supported the visualization of the performance patterns in the present study and showed that multilayer substrate configuration, season, and sampling locations significantly influenced biofilm growth and solids accumulation. Finally, the present study provided important information to support the improved multilayer configured HSCW implication in the future.}, } @article {pmid29102134, year = {2018}, author = {Ye, Y and Zhang, M and Jiao, R and Ling, N and Zhang, X and Tong, L and Zeng, H and Zhang, J and Wu, Q}, title = {Inactivation of Cronobacter malonaticus cells and inhibition of its biofilm formation exposed to hydrogen peroxide stress.}, journal = {Journal of dairy science}, volume = {101}, number = {1}, pages = {66-74}, doi = {10.3168/jds.2017-13463}, pmid = {29102134}, issn = {1525-3198}, mesh = {Biofilms/*drug effects ; Cronobacter/*drug effects/growth & development/*physiology ; Food Handling ; Food Microbiology ; Hydrogen Peroxide/*pharmacology ; Infant Formula/microbiology ; }, abstract = {Presence of Cronobacter malonaticus in powdered infant formula (PIF) poses a high risk to infant and public health. Cronobacter malonaticus has been widely distributed in food and food processing environments, and the true origin of C. malonaticus in PIF is poorly understood. Control and prevention of C. malonaticus is necessary for achieving microbial safety of PIF. However, little information about decontamination of C. malonaticus is available. In this study, effects of hydrogen peroxide on inactivation and morphological changes of C. malonaticus cells were determined. Furthermore, inhibitory effects of H2O2 on biofilm formation in C. malonaticus were also performed. Results indicated that H2O2 could completely inactivate C. malonaticus in sterile water with 0.06% H2O2 for 25 min, 0.08% H2O2 for 15 min, and 0.10% for 10 min, respectively, whereas the survival rates of C. malonaticus in tryptic soy broth medium significantly increased with the same treatment time and concentration of H2O2. In addition, morphological changes of C. malonaticus cells, including cell shrinkage, disruption of cells, cell intercession, and leakage of intercellular material in sterile water after H2O2 treatment, were more predominant than those in tryptic soy broth. Finally, significant reduction in biofilm formation by H2O2 was found using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy detection compared with control samples. This is the first report to determine the effects of H2O2 on C. malonaticus cells and biofilm formation. The findings provided valuable information for practical application of H2O2 for decontamination of C. malonaticus in dairy processing.}, } @article {pmid29101702, year = {2018}, author = {Yang, Y and Chen, W and Yi, Z and Pei, G}, title = {The integrative effect of periphyton biofilm and tape grass (Vallisneria natans) on internal loading of shallow eutrophic lakes.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {2}, pages = {1773-1783}, pmid = {29101702}, issn = {1614-7499}, support = {30970550//the National Science Foundation of China/ ; 2015CFB416//the National Science Foundation of Hubei Province/ ; }, mesh = {Biofilms/*growth & development ; Biomass ; Ecosystem ; Environmental Restoration and Remediation ; *Eutrophication ; Hydrocharitaceae/*growth & development ; *Lakes/chemistry ; Nitrogen/analysis ; Periphyton/*physiology ; Phosphorus/analysis ; Water/analysis/chemistry ; }, abstract = {The response of periphyton biofilm and the submerged macrophyte tape grass (Vallisneria natans) to internal loading from eutrophic lake sediments were evaluated in microcosms. The sediments from the littoral zone and center of a lake were selected to carry out the microcosm experiment. To determine how the differences in the periphyton biofilm and V. natans growth alone or in combination, we measured changes in water quality, growth, and TP in the periphyton biofilm and V. natans in microcosms containing these sediments. The results showed that the average daily TN and TP removal rates were 32.6 and 35.4%, respectively, in the microcosms containing the lake center sediments by V. natans and the periphyton biofilm. The presence of the periphyton biofilm and V. natans increased the pH, dissolved oxygen, and redox potential and decreased the conductivity in the overlying water in all treatments. Compared to the state before the treatments, V. natans grew well, with a significant increase in biomass (3.1- to 5.5-fold growth) and TP amount (5.1- to 8.8-fold) in all treatments after 48 days. However, the growth of V. natans that combined with the periphyton biofilm was better than that of V. natans alone, as reflected by the dry weight, chlorophyll a content, malondialdehyde content, and TP amount. In conclusion, the periphyton biofilm was beneficial for the growth of V. natans, and the appropriate combination of V. natans and periphyton biofilm would be a potential method for the ecological restoration of eutrophic lakes.}, } @article {pmid29101490, year = {2018}, author = {Ramanathan, S and Ravindran, D and Arunachalam, K and Arumugam, VR}, title = {Inhibition of quorum sensing-dependent biofilm and virulence genes expression in environmental pathogen Serratia marcescens by petroselinic acid.}, journal = {Antonie van Leeuwenhoek}, volume = {111}, number = {4}, pages = {501-515}, doi = {10.1007/s10482-017-0971-y}, pmid = {29101490}, issn = {1572-9699}, support = {BT/BI/25/015/2012//Department of Biotechnology , Ministry of Science and Technology/ ; F.4-1/2006(BSR)/7-326/2011(BSR)//University Grants Commission/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Oleic Acids/*pharmacology ; Polysaccharides, Bacterial/genetics ; Quorum Sensing/*genetics ; Serratia marcescens/*drug effects/*physiology ; Spectroscopy, Fourier Transform Infrared ; Virulence/*drug effects/genetics ; Virulence Factors/genetics ; }, abstract = {The aim of this study was to evaluate the anti-biofilm and anti-virulence properties of petroselinic acid (PSA) against the environmental pathogen Serratia marcescens. PSA significantly inhibited the quorum sensing (QS)-dependent virulence factors such as prodigiosin, protease productions, and biofilm formation in S. marcescens. The antibiofilm potential of PSA was also confirmed through light, confocal laser scanning, and scanning electron microscopic analyses. Furthermore, PSA effectively inhibited the biofilm-related phenomena such as exopolysaccharide production, hydrophobicity production, swimming, and swarming motility without affecting the bacterial growth. In FT-IR analysis, the PSA treated S. marcescens cells displayed a reduction in cellular components compared to the untreated controls. The real-time analysis revealed the downregulation of QS-controlled virulence genes such as bsmB, fimA, fimC, and flhD in S. marcescens on treatment with PSA. The obtained results strongly suggested that PSA could be further explored as an antipathogenic drug to treat QS-mediated infections caused by S. marcescens.}, } @article {pmid29101088, year = {2017}, author = {Nemezio, MA and de Souza Farias, SS and Borsatto, MC and Aires, CP and Corona, SAM}, title = {Effect of methylene blue-induced photodynamic therapy on a Streptococcus mutans biofilm model.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {20}, number = {}, pages = {234-237}, doi = {10.1016/j.pdpdt.2017.10.025}, pmid = {29101088}, issn = {1873-1597}, mesh = {Bacterial Load ; Biofilms/*drug effects ; Lasers, Semiconductor ; Methylene Blue/*pharmacology ; Microbial Viability ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Polysaccharides, Bacterial/metabolism ; Streptococcus mutans/*drug effects ; }, abstract = {BACKGROUND: Several studies have reported the use of antimicrobial photodynamic therapy (aPDT) to control biofilm but its efficacy depends on several factors, such as biofilm model used. This study aims to examine whether exposure to diode laser combined with methylene blue affects the bacterial viability and polysaccharide content in a Streptococcus mutans cariogenic biofilm model, which simulated 'feast-famine' episodes of exposure to sucrose that occur in the oral cavity.

MATERIALS AND METHODS: S. mutans biofilms were formed on acrylic resin discs and exposed to a 10% sucrose solution for 1min, eight times/day. After growing for 48h, the biofilms were submitted to the following treatments, twice daily (n=4): (i) 0.9% NaCl (NaCl) as the negative control; (ii) 0.12% chlorhexidine digluconate (CHX) as the positive antibacterial control; (iii) diode laser combined with methylene blue, using an energy density of 320J/cm[2] (aPDT). After 120h of growth, the biofilm formed on each disc was collected to determine the viable bacterial counts and concentration of insoluble exopolysaccharides (IEPS) and intracellular polysaccharides (IPS).

RESULTS: Bacterial counts in the biofilms formed differed among the treatments. Compared with NaCl, aPDT significantly destabilized biofilm (p<0.0001). aPDT and CHX equally lowered the concentration of IEPS and IPS in biofilms.

CONCLUSION: Under the experimental conditions assessed, our findings indicate that a twice-daily treatment with diode laser combined with methylene blue effectively decreased bacterial viability and the intra- and extracellular polysaccharide concentration in biofilms of S. mutans, a cariogenic bacterium.}, } @article {pmid29100930, year = {2018}, author = {Iñiguez-Moreno, M and Gutiérrez-Lomelí, M and Guerrero-Medina, PJ and Avila-Novoa, MG}, title = {Biofilm formation by Staphylococcus aureus and Salmonella spp. under mono and dual-species conditions and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {49}, number = {2}, pages = {310-319}, pmid = {29100930}, issn = {1678-4405}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Cetrimonium ; Cetrimonium Compounds/*pharmacology ; Colony Count, Microbial ; Culture Media/chemistry ; Disinfectants/*pharmacology ; Environmental Microbiology ; Microbial Interactions ; Microbial Viability/drug effects ; Peracetic Acid/*pharmacology ; Polypropylenes ; Salmonella/*drug effects/growth & development ; Sodium Hypochlorite/*pharmacology ; Stainless Steel ; Staphylococcus aureus/*drug effects/growth & development ; Temperature ; Time ; }, abstract = {The aim of this study was evaluated the biofilm formation by Staphylococcus aureus 4E and Salmonella spp. under mono and dual-species biofilms, onto stainless steel 316 (SS) and polypropylene B (PP), and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite. The biofilms were developed by immersion of the surfaces in TSB by 10 d at 37°C. The results showed that in monospecies biofilms the type of surface not affected the cellular density (p>0.05). However, in dual-species biofilms on PP the adhesion of Salmonella spp. was favored, 7.61±0.13Log10CFU/cm[2], compared with monospecies biofilms onto the same surface, 5.91±0.44Log10CFU/cm[2] (p<0.05). The mono and dual-species biofilms were subjected to disinfection treatments; and the most effective disinfectant was peracetic acid (3500ppm), reducing by more than 5Log10CFU/cm[2], while the least effective was cetrimonium bromide. In addition, S. aureus 4E and Salmonella spp. were more resistant to the disinfectants in mono than in dual-species biofilms (p<0.05). Therefore, the interspecies interactions between S. aureus 4E and Salmonella spp. had a negative effect on the antimicrobial resistance of each microorganism, compared with the monospecies biofilms.}, } @article {pmid29099398, year = {2019}, author = {Barki, KG and Das, A and Dixith, S and Ghatak, PD and Mathew-Steiner, S and Schwab, E and Khanna, S and Wozniak, DJ and Roy, S and Sen, CK}, title = {Electric Field Based Dressing Disrupts Mixed-Species Bacterial Biofilm Infection and Restores Functional Wound Healing.}, journal = {Annals of surgery}, volume = {269}, number = {4}, pages = {756-766}, pmid = {29099398}, issn = {1528-1140}, support = {R01 NS042617/NS/NINDS NIH HHS/United States ; R01 DK114718/DK/NIDDK NIH HHS/United States ; R01 NR013898/NR/NINR NIH HHS/United States ; R01 GM077185/GM/NIGMS NIH HHS/United States ; R56 DK076566/DK/NIDDK NIH HHS/United States ; R01 NR015676/NR/NINR NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; R01 GM069589/GM/NIGMS NIH HHS/United States ; R01 DK076566/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; *Bandages ; *Biofilms ; Electricity ; Equipment Design ; Female ; Swine ; *Wound Healing ; Wound Infection/*therapy ; }, abstract = {OBJECTIVE: This study was designed to employ electroceutical principles, as an alternative to pharmacological intervention, to manage wound biofilm infection. Mechanism of action of a United States Food and Drug Administration-cleared wireless electroceutical dressing (WED) was tested in an established porcine chronic wound polymicrobial biofilm infection model involving inoculation with Pseudomonas aeruginosa PAO1 and Acinetobacter baumannii 19606.

BACKGROUND: Bacterial biofilms represent a major wound complication. Resistance of biofilm toward pharmacologic interventions calls for alternative therapeutic strategies. Weak electric field has anti-biofilm properties. We have previously reported the development of WED involving patterned deposition of Ag and Zn on fabric. When moistened, WED generates a weak electric field without any external power supply and can be used as any other disposable dressing.

METHODS: WED dressing was applied within 2 hours of wound infection to test its ability to prevent biofilm formation. Alternatively, WED was applied after 7 days of infection to study disruption of established biofilm. Wounds were treated with placebo dressing or WED twice a week for 56 days.

RESULTS: Scanning electron microscopy demonstrated that WED prevented and disrupted wound biofilm aggregates. WED accelerated functional wound closure by restoring skin barrier function. WED blunted biofilm-induced expression of (1) P. aeruginosa quorum sensing mvfR (pqsR), rhlR and lasR genes, and (2) miR-9 and silencing of E-cadherin. E-cadherin is critically required for skin barrier function. Furthermore, WED rescued against biofilm-induced persistent inflammation by circumventing nuclear factor kappa B activation and its downstream cytokine responses.

CONCLUSION: This is the first pre-clinical porcine mechanistic study to recognize the potential of electroceuticals as an effective platform technology to combat wound biofilm infection.}, } @article {pmid29098937, year = {2017}, author = {Shimamura, Y and Hirai, C and Sugiyama, Y and Shibata, M and Ozaki, J and Murata, M and Ohashi, N and Masuda, S}, title = {Inhibitory effects of food additives derived from polyphenols on staphylococcal enterotoxin A production and biofilm formation by Staphylococcus aureus.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {81}, number = {12}, pages = {2346-2352}, doi = {10.1080/09168451.2017.1395681}, pmid = {29098937}, issn = {1347-6947}, mesh = {Biofilms/*drug effects/growth & development ; Enterotoxins/*biosynthesis/genetics ; Food Additives/*chemistry ; Gene Expression Regulation, Bacterial/drug effects ; Polyphenols/*chemistry/*pharmacology ; Staphylococcus aureus/*drug effects/genetics/*metabolism/physiology ; }, abstract = {In this study, we examined the inhibitory effects of 14 food additives derived from polyphenol samples on staphylococcal enterotoxin A (SEA) production and biofilm formation by Staphylococcus aureus. Tannic acid AL (TA), Purephenon 50 W (PP) and Polyphenon 70A (POP) at 0.25 mg/mL and Gravinol®-N (GN), Blackcurrant polyphenol AC10 (BP), and Resveratrol-P5 (RT) at 1.0 mg/mL significantly decreased SEA production by S. aureus C-29 (p < 0.05). TA, GN, BP, and RT significantly inhibited the expression of the sea gene in S. aureus C-29 (p < 0.05), while suppression attempts by PP and POP proved unsuccessful. After result analysis, it can be derived that TA, GN, BP, and RT inhibit the production of SEA. Of the six samples, each one significantly inhibited biofilm formation (p < 0.05). Food additives derived from polyphenols have viability to be used as a means to inhibit the enterotoxin production and control the biofilm formation of foodborne pathogens.}, } @article {pmid29097104, year = {2018}, author = {Johani, K and Abualsaud, D and Costa, DM and Hu, H and Whiteley, G and Deva, A and Vickery, K}, title = {Characterization of microbial community composition, antimicrobial resistance and biofilm on intensive care surfaces.}, journal = {Journal of infection and public health}, volume = {11}, number = {3}, pages = {418-424}, doi = {10.1016/j.jiph.2017.10.005}, pmid = {29097104}, issn = {1876-035X}, mesh = {Adenosine Triphosphate/analysis ; Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/*isolation & purification/metabolism/ultrastructure ; Biofilms/drug effects/*growth & development ; Cross Infection/microbiology ; Drug Resistance, Bacterial ; *Drug Resistance, Multiple, Bacterial ; Humans ; *Intensive Care Units ; *Microbial Consortia ; Microscopy, Electron, Scanning ; Saudi Arabia ; Surface Properties ; }, abstract = {BACKGROUND: Organisms causing healthcare associated infections can be sourced from the inanimate environment around patients. Residing in a biofilm increases the chances of these organisms persisting in the environment. We aimed to characterise bacterial environmental contamination, genetically and physiologically, and relate this to general intensive care unit (ICU) cleanliness.

METHODS: Cleanliness was determined by adenosine triphosphate (ATP) measurements of 95 high-touch objects. Bacteriological samples were obtained from the same sites (n=95) and from aseptically removed sections (destructive samples, n=20). Bacterial enrichment culture was conducted using tryptone soya broth prior to plating on horse blood agar, MacConkey agar, and screening chromogenic agar for identification of multidrug resistance organism (MDRO). Bacterial load and microbial diversity were determined using quantitative PCR (qPCR) and next generation DNA sequencing respectively. Confocal laser scanning microscopy and scanning electron microscopy were used to visually confirm the biofilm presence.

RESULTS: Many intensive care surfaces (61%) were highly contaminated by biological soil as determined by ATP bioluminescence testing. The degree of biological soiling was not associated with bacterial contamination as detected by qPCR. Bacterial load ranged from 78.21 to 3.71×10[8] (median=900) bacteria/100cm[2]. Surface swabs from 71/95 sites (75%) were culture-positive; of these 16 (22.5%) contained MDRO. The most abundant genera were Staphylococcus, Propionibacterium, Pseudomonas, Bacillus, Enterococcus, Streptococcus and Acinetobacter. Biofilm was visually confirmed by microscopy on 70% (14/20) of items.

CONCLUSION: Bacterial biofilms and MDROs were found on ICU surfaces despite regular cleaning in Saudi Arabia, suggesting that biofilm development is not controlled by current cleaning practices.}, } @article {pmid29096652, year = {2017}, author = {Baniya, B and Pant, ND and Neupane, S and Khatiwada, S and Yadav, UN and Bhandari, N and Khadka, R and Bhatta, S and Chaudhary, R}, title = {Biofilm and metallo beta-lactamase production among the strains of Pseudomonas aeruginosa and Acinetobacter spp. at a Tertiary Care Hospital in Kathmandu, Nepal.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {16}, number = {1}, pages = {70}, pmid = {29096652}, issn = {1476-0711}, mesh = {Acinetobacter/drug effects/*isolation & purification/*metabolism ; Acinetobacter Infections/microbiology ; Adhesins, Bacterial/analysis ; Anti-Bacterial Agents ; Biofilms/*growth & development ; Colistin/pharmacology ; Disk Diffusion Antimicrobial Tests ; Humans ; Nepal ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/drug effects/*isolation & purification/*metabolism ; *Tertiary Care Centers ; beta-Lactam Resistance ; beta-Lactamases/*biosynthesis ; }, abstract = {INTRODUCTION: Pseudomonas aeruginosa and Acinetobacter spp. are found to be associated with biofilm and metallo-β-lactamase production and are the common causes of serious infections mainly in hospitalized patients. So, the main aims of this study were to determine the rates of biofilm production and metallo beta-lactamase production (MBL) among the strains of Pseudomonas aeruginosa and Acinetobacter spp. isolated from hospitalized patients.

METHODS: A total of 85 P. aeruginosa isolates and 50 Acinetobacter spp. isolates isolated from different clinical specimens from patients admitted to Shree Birendra Hospital, Kathmandu, Nepal from July 2013 to May 2014 were included in this study. The bacterial isolates were identified with the help of biochemical tests. Modified Kirby-Bauer disc diffusion technique was used for antimicrobial susceptibility testing. Combined disc diffusion technique was used for the detection of MBL production, while Congo red agar method and tube adherence method were used for detection of biofilm production.

RESULTS: Around 16.4% of P. aeruginosa isolates and 22% of the strains of Acinetobacter spp. were metallo β-lactamase producers. Out of 85 P. aeruginosa isolates, 23 (27.05%) were biofilm producers according to tube adherence test while, only 13 (15.29%) were biofilm producers as per Congo red agar method. Similarly, out of 50 Acinetobacter spp. 7 (14%) isolates were biofilm producers on the basis of tube adherence test, while only 5 (10%) were positive for biofilm production by Congo red agar method. Highest rates of susceptibility of P. aeruginosa as well as Acinetobacter spp. were seen toward colistin.

CONCLUSION: In our study, biofilm production and metallo beta-lactamase production were observed among Pseudomonas aeruginosa and Acinetobacter spp. However, no statistically significant association could be established between biofilm production and metallo beta-lactamase production.}, } @article {pmid29096369, year = {2018}, author = {Butini, ME and Cabric, S and Trampuz, A and Di Luca, M}, title = {In vitro anti-biofilm activity of a biphasic gentamicin-loaded calcium sulfate/hydroxyapatite bone graft substitute.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {161}, number = {}, pages = {252-260}, doi = {10.1016/j.colsurfb.2017.10.050}, pmid = {29096369}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemistry/pharmacokinetics/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Bone Substitutes/chemistry/*pharmacology ; Calcium Sulfate/*chemistry ; Drug Liberation ; Durapatite/*chemistry ; Escherichia coli/drug effects/physiology ; Gentamicins/chemistry/pharmacokinetics/*pharmacology ; Humans ; Microbial Sensitivity Tests/methods ; Prosthesis-Related Infections/*drug therapy/microbiology ; Staphylococcus aureus/drug effects/physiology ; Staphylococcus epidermidis/drug effects/physiology ; }, abstract = {Bone and implant-associated infections caused by microorganisms that grow in biofilms are difficult to treat because of persistence and recurrence of infection. Along with surgical debridement, the combination of systemic and local administration of antimicrobials represents the background for an efficient treatment strategy. Gentamicin is one of most used antibiotics for the local treatment of bone-related infections, alone or in combination, due to its bactericidal and broad-range activity. Gentamicin-loaded beads (GLBs), composed of calcium sulfate/hydroxyapatite, were assessed for their in vitro antimicrobial activity against planktonic and biofilm S. agalactiae, S. aureus, S. epidermidis, E. faecalis and E. coli, using standard methods and ultra-sensitive isothermal microcalorimetry. Gentamicin released from GLBs to clinically relevant concentrations (200-2500μg/mL) within 1h was able to kill planktonic S. agalactiae, S. epidermidis and E. coli at lower concentrations (MIC: ≤4μg/mL). Moreover, 12 and 23μg/mL of released gentamicin were able to prevent bacterial adhesion and suppress a 24h-old biofilm of E. coli, respectively. Conversely, higher amounts of antibiotic, ranging from 171 to 1260μg/mL, were needed to prevent and eradicate biofilms of gram-positive bacteria. Likewise, the emergence of resistance to GLBs in vitro and the bacterial attachment on the bone graft substitute, when the amount of gentamicin in the material is reduced, were also reported. This study provides further information regarding the in vitro anti-biofilm activity of the biphasic gentamicin-loaded bone graft substitute, suggesting the validity of this antibiotic-loaded material for the prophylaxis and treatment of bone and implant-associated infections.}, } @article {pmid29096256, year = {2018}, author = {Yue, W and Chen, M and Cheng, Z and Xie, L and Li, M}, title = {Bioaugmentation of strain Methylobacterium sp. C1 towards p-nitrophenol removal with broad spectrum coaggregating bacteria in sequencing batch biofilm reactors.}, journal = {Journal of hazardous materials}, volume = {344}, number = {}, pages = {431-440}, doi = {10.1016/j.jhazmat.2017.10.039}, pmid = {29096256}, issn = {1873-3336}, mesh = {Bacteria/genetics/*metabolism ; Biofilms ; Bioreactors/*microbiology ; Nitrophenols/*metabolism ; RNA, Ribosomal, 16S/genetics ; Water Pollutants, Chemical/*metabolism ; }, abstract = {This work was conducted in order to evaluate an instance of bioaugmentation, namely, the addition of a novel p-nitrophenol (PNP)-degrading bacterium Methylobacterium sp. C1 coaggregated with two other broad-spectrum coaggregating strains (Bacillus megaterium T1 and Bacillus cereus G5) within sequence batch biofilm reactors (SBBRs). Results showed that biofilms consisting of C1 and coaggregating bacteria were resistant to shock loads and were more efficient at PNP removal. High-throughput sequencing data revealed that biofilms formed in the presence of the coaggregating bacteria demonstrated greater microbial diversity. These results suggest that broad-spectrum coaggregating bacteria may be capable of mediating the immobilization of exogenous degrading bacteria into biofilms, rendering them more resistant to toxic compounds and environmental stresses. This represents the first attempt to assess the bioaugmentation of PNP-contaminated wastewater treatment through the utilization of broad-spectrum coaggregating bacteria.}, } @article {pmid29094950, year = {2017}, author = {Kaufman, G and Liu, W and Williams, DM and Choo, Y and Gopinadhan, M and Samudrala, N and Sarfati, R and Yan, ECY and Regan, L and Osuji, CO}, title = {Flat Drops, Elastic Sheets, and Microcapsules by Interfacial Assembly of a Bacterial Biofilm Protein, BslA.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {33}, number = {47}, pages = {13590-13597}, doi = {10.1021/acs.langmuir.7b03226}, pmid = {29094950}, issn = {1520-5827}, mesh = {Bacterial Proteins ; *Biofilms ; Capsules ; Emulsions ; Hydrophobic and Hydrophilic Interactions ; }, abstract = {Protein adsorption and assembly at interfaces provide a potentially versatile route to create useful constructs for fluid compartmentalization. In this context, we consider the interfacial assembly of a bacterial biofilm protein, BslA, at air-water and oil-water interfaces. Densely packed, high modulus monolayers form at air-water interfaces, leading to the formation of flattened sessile water drops. BslA forms elastic sheets at oil-water interfaces, leading to the production of stable monodisperse oil-in-water microcapsules. By contrast, water-in-oil microcapsules are unstable but display arrested rather than full coalescence on contact. The disparity in stability likely originates from a low areal density of BslA hydrophobic caps on the exterior surface of water-in-oil microcapsules, relative to the inverse case. In direct analogy with small molecule surfactants, the lack of stability of individual water-in-oil microcapsules is consistent with the large value of the hydrophilic-lipophilic balance (HLB number) calculated based on the BslA crystal structure. The occurrence of arrested coalescence indicates that the surface activity of BslA is similar to that of colloidal particles that produce Pickering emulsions, with the stability of partially coalesced structures ensured by interfacial jamming. Micropipette aspiration and flow in tapered capillaries experiments reveal intriguing reversible and nonreversible modes of mechanical deformation, respectively. The mechanical robustness of the microcapsules and the ability to engineer their shape and to design highly specific binding responses through protein engineering suggest that these microcapsules may be useful for biomedical applications.}, } @article {pmid29094611, year = {2017}, author = {Alves, R and Mota, S and Silva, S and F Rodrigues, C and P Brown, AJ and Henriques, M and Casal, M and Paiva, S}, title = {The carboxylic acid transporters Jen1 and Jen2 affect the architecture and fluconazole susceptibility of Candida albicans biofilm in the presence of lactate.}, journal = {Biofouling}, volume = {33}, number = {10}, pages = {943-954}, doi = {10.1080/08927014.2017.1392514}, pmid = {29094611}, issn = {1029-2454}, support = {MR/M026663/1//Medical Research Council/United Kingdom ; BB/K017365/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adaptation, Physiological ; Antifungal Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Biofouling/prevention & control ; Candida albicans/*drug effects/genetics/physiology ; Carboxylic Acids/metabolism ; Cellular Microenvironment ; Drug Resistance, Fungal ; Fluconazole/*pharmacology ; Fungal Proteins/genetics/metabolism/*physiology ; Glucose/metabolism ; Lactic Acid/*metabolism ; Monocarboxylic Acid Transporters/genetics/metabolism/*physiology ; }, abstract = {Candida albicans has the ability to adapt to different host niches, often glucose-limited but rich in alternative carbon sources. In these glucose-poor microenvironments, this pathogen expresses JEN1 and JEN2 genes, encoding carboxylate transporters, which are important in the early stages of infection. This work investigated how host microenvironments, in particular acidic containing lactic acid, affect C. albicans biofilm formation and antifungal drug resistance. Multiple components of the extracellular matrix were also analysed, including their impact on antifungal drug resistance, and the involvement of both Jen1 and Jen2 in this process. The results show that growth on lactate affects biofilm formation, morphology and susceptibility to fluconazole and that both Jen1 and Jen2 might play a role in these processes. These results support the view that the adaptation of Candida cells to the carbon source present in the host niches affects their pathogenicity.}, } @article {pmid29094001, year = {2017}, author = {Ghorbani, H and Memar, MY and Sefidan, FY and Yekani, M and Ghotaslou, R}, title = {In vitro synergy of antibiotic combinations against planktonic and biofilm Pseudomonas aeruginosa.}, journal = {GMS hygiene and infection control}, volume = {12}, number = {}, pages = {Doc17}, pmid = {29094001}, issn = {2196-5226}, abstract = {Aim: The combination of different antimicrobial agents and subsequent synergetic effects may be beneficial in treatment of P. aeruginosa infections. The aim of the present study was to determine antibiotic susceptibility patterns of clinical isolates of P. aeruginosa and the effect of different antibiotic combinations against the multidrug-resistant (MDR), biofilm-producing bacterium P. aeruginosa. Methods: Thirty-six P. aeruginosa clinical isolates were evaluated. The disk diffusion method was performed to determine antibiotic susceptibility patterns according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The minimum inhibitory concentration of antimicrobial agents for the test organisms was determined by the broth microdilution method. To determine synergetic effects of the combinations of agents, the checkerboard assay and the fractional inhibitory concentration were used. The biofilm inhibitory concentration was determined to detect any inhibitory effect of antibiotics against the biofilm. Results: High levels of resistance were detected against most antibiotics, except colistin and polymyxin. According to the disk diffusion method, 58.3% of isolates were MDR. A synergetic effect between amikacin/ceftazidime, tobramycin/colistin and ceftazidime/colistin was found in 55.6%, 58.3% and 52.8% of isolates, respectively. A significant synergetic effect against biofilm-producing isolates was observed for the combination of tobramycin (0.5-1 µg/ml) and clarithromycin (256-512 µg/ml). Conclusion: Combinations of antibiotics have a different activity on the biofilm and planktonic forms of P. aeruginosa. Consequently, separate detection of antibacterial and antibiofilm effects of the antibiotic combinations may be useful in guiding the antibiotic therapy.}, } @article {pmid29093703, year = {2017}, author = {Rosenblatt, J and Reitzel, RA and Vargas-Cruz, N and Chaftari, AM and Hachem, R and Raad, I}, title = {Caprylic and Polygalacturonic Acid Combinations for Eradication of Microbial Organisms Embedded in Biofilm.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1999}, pmid = {29093703}, issn = {1664-302X}, abstract = {There is a need for non-antibiotic, antimicrobial compositions with low toxicity capable of broad-spectrum eradication of pathogenic biofilms in food preparation and healthcare settings. In this study we demonstrated complete biofilm eradication within 60 min with synergistic combinations of caprylic and polygalacturonic (PG) acids in an in vitro biofilm eradication model against representative hospital and foodborne infectious pathogen biofilms (methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, Candida albicans, Escherichia coli, and Salmonella enteritidis). Antimicrobial synergy against biofilms was demonstrated by quantifying viable organisms remaining in biofilms exposed to caprylic acid alone, PG acid alone, or combinations of the two. The combinations also synergistically inhibited growth of planktonic organisms. Toxicity of the combination was assessed in vitro on L929 fibroblasts incubated with extracts of caprylic and PG acid combinations using the Alamar Blue metabolic activity assay and the Trypan Blue exclusion cell viability assay. The extracts did not produce cytotoxic responses relative to untreated control fibroblasts.}, } @article {pmid29091851, year = {2018}, author = {Wang, YQ and Zhang, F and Zhang, W and Dai, K and Wang, HJ and Li, X and Zeng, RJ}, title = {Hydrogen and carbon dioxide mixed culture fermentation in a hollow-fiber membrane biofilm reactor at 25 °C.}, journal = {Bioresource technology}, volume = {249}, number = {}, pages = {659-665}, doi = {10.1016/j.biortech.2017.10.054}, pmid = {29091851}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; *Carbon Dioxide ; Clostridium ; *Fermentation ; Hydrogen ; }, abstract = {There have been no reports of H2 and CO2 mixed-culture fermentation (MCF) at 25 °C in a hollow-fiber membrane biofilm reactor (HfMBR). In this study, H2 and CO2 MCF were conducted in an HfMBR at 25 °C producing metabolites including acetate, ethanol, butyrate, and caproate. Compared to pure culture fermentation (i.e., Clostridium carboxidivorans P7), the MCF in HfMBR at 25 °C produced a higher concentration of caproate in this study (3.4 g/L in batch 1 and 5.7 g/L in batch 2). The dominant genera were Clostridium_sensu_stricto_12 and Prevotella_7. The caproate was more likely formed from the pathway of acetate and ethanol rather than via butyrate and ethanol. Since caproate is more valuable than acetate and low temperature fermentation consumes less energy, this process of H2 and CO2 MCF at 25 °C is appropriate for industrial application.}, } @article {pmid29090281, year = {2017}, author = {Gandhi, AD and Vizhi, DK and Lavanya, K and Kalpana, VN and Devi Rajeswari, V and Babujanarthanam, R}, title = {In vitro anti- biofilm and anti-bacterial activity of Sesbania grandiflora extract against Staphylococcus aureus.}, journal = {Biochemistry and biophysics reports}, volume = {12}, number = {}, pages = {193-197}, pmid = {29090281}, issn = {2405-5808}, abstract = {The main objective of this research is to investigate the anti-biofilm and anti-bacterial activity of Sesbania grandiflora (S. grandiflora) against Staphylococcus aureus. S. grandiflora extract were prepared and analyzed with UV -Vis spectroscopy, Fourier transform infrared spectroscopy, Dynamic light scattering. Biofilm forming pathogens were identified by congo-red assay. Quantification of Extracellular polymeric substance (EPS) particularly protein and carbohydrate were calculated. The efficacy of the herbal extract S. grandiflora and its inhibition against the pathogenic strain of S. aureus was also evaluated. The gradual decrease or disappearance of peaks reveals the reduction of protein and carbohydrate content in the EPS of S. aureus when treated with S. grandiflora. The antibacterial activity of S. grandiflora extract against the bacterial strain S. aureus showed that the extract were more active against the strain. To conclude, anti-biofilm and antibacterial efficacy of S. grandiflora plays a vital role over biofilm producing pathogens and act as a good source for controlling the microbial population.}, } @article {pmid29089559, year = {2017}, author = {Jabli, M and Saleh, TA and Sebeia, N and Tka, N and Khiari, R}, title = {Dimethyl diallyl ammonium chloride and diallylamin Co-polymer modified bio-film derived from palm dates for the adsorption of dyes.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {14448}, pmid = {29089559}, issn = {2045-2322}, abstract = {For the first time, co-polymer of dimethyl diallyl ammonium chloride and diallylamin (PDDACD) was used to modify the films derived from the waste of palm date fruits, which were then investigated by the purification of colored aqueous solutions. The physico-chemical characteristics were identified using data color, FT-IR spectroscopy, and SEM features. The modified films were evaluated as adsorbents of Methylene Blue (MB), Direct Yellow 50 (DY50), Reactive Blue 198 (RB198) and Naphtol Blue Black (NBB). High retention capacities were achieved in the following order: The equilibrium da DY50 (14 mg g[-1]) < RB198 (16 mg g[-1]) < NBB (63.9 mg g[-1]) < MB (150 mg g[-1]). The kinetic modeling of the data revealed that the adsorption data follows the pseudo second order model. It was fitted to the Langmuir, Freundlich, Temkin, and Dubinin-Redushkevich equations, and the data best fit the Freundlich model indicating that the adsorption might occur in the heterogeneous adsorption sites. These results reveal that PDDACD modified films are valuable materials for the treatment of industrial wastewater. Moreover, the as-prepared adsorbent is economically viable and easily controllable for pollutant adsorption.}, } @article {pmid29089020, year = {2017}, author = {Chin, KCJ and Taylor, TD and Hebrard, M and Anbalagan, K and Dashti, MG and Phua, KK}, title = {Transcriptomic study of Salmonella enterica subspecies enterica serovar Typhi biofilm.}, journal = {BMC genomics}, volume = {18}, number = {1}, pages = {836}, pmid = {29089020}, issn = {1471-2164}, mesh = {Biofilms/*growth & development ; *Gene Expression Profiling/methods ; *Gene Expression Regulation, Bacterial ; High-Throughput Nucleotide Sequencing ; Humans ; Salmonella typhi/*genetics/*growth & development ; *Transcriptome ; }, abstract = {BACKGROUND: Typhoid fever is an acute systemic infection of humans caused by Salmonella enterica subspecies enterica serovar Typhi (S. Typhi). In chronic carriers, the bacteria survive the harsh environment of the gallbladder by producing biofilm. The phenotype of S. Typhi biofilm cells is significantly different from the free-swimming planktonic cells, and studies have shown that they are associated with antibiotic resistance, immune system evasion, and bacterial persistence. However, the mechanism of this transition and the events leading to biofilm formation are unknown. High throughput sequencing was performed to identify the genes involved in biofilm formation and to postulate the mechanism of action.

RESULTS: Planktonic S. Typhi cells were cultured using standard nutrient broth whereas biofilm cells were cultured in a stressful environment using high shearing-force and bile to mimic the gallbladder. Sequencing libraries were prepared from S. Typhi planktonic cells and mature biofilm cells using the Illumina HiSeq 2500 platform, and the transcriptome data obtained were processed using Cufflinks bioinformatics suite of programs to investigate differential gene expression between the two phenotypes. A total of 35 up-regulated and 29 down-regulated genes were identified. The identities of the differentially expressed genes were confirmed using NCBI BLAST and their functions were analyzed. The results showed that the genes associated with metabolic processes and biofilm regulations were down-regulated while those associated with the membrane matrix and antibiotic resistance were highly up-regulated.

CONCLUSIONS: It is proposed that the biofilm phenotype of S. Typhi allows the bacteria to increase production of the membrane matrix in order to serve as a physical shield and to adhere to surfaces, and enter an energy conservation state in response to the stressful environment. Conversely, the planktonic phenotype allows the bacteria to produce flagella and increase metabolic activity to enable the bacteria to migrate and form new colonies of infection. This data provide a basis for further studies to uncover the mechanism of biofilm formation in S. Typhi and to discover novel genes or pathways associated with the development of the typhoid carrier state.}, } @article {pmid29087319, year = {2017}, author = {Jain, N and Ådén, J and Nagamatsu, K and Evans, ML and Li, X and McMichael, B and Ivanova, MI and Almqvist, F and Buxbaum, JN and Chapman, MR}, title = {Inhibition of curli assembly and Escherichia coli biofilm formation by the human systemic amyloid precursor transthyretin.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {46}, pages = {12184-12189}, pmid = {29087319}, issn = {1091-6490}, support = {R01 AI099099/AI/NIAID NIH HHS/United States ; R01 GM118651/GM/NIGMS NIH HHS/United States ; T32 GM008353/GM/NIGMS NIH HHS/United States ; }, mesh = {Amyloid/antagonists & inhibitors/*chemistry/metabolism ; Amyloidogenic Proteins/antagonists & inhibitors/*chemistry/genetics/metabolism ; Binding Sites ; Biofilms/*drug effects/growth & development ; Escherichia coli/*drug effects/genetics/metabolism ; Escherichia coli Proteins/antagonists & inhibitors/*chemistry/genetics/metabolism ; Gene Expression ; Humans ; Kinetics ; Prealbumin/chemistry/metabolism/*pharmacology ; Protein Aggregates/drug effects ; Protein Binding ; Protein Interaction Domains and Motifs ; Protein Multimerization ; }, abstract = {During biofilm formation, Escherichia coli and other Enterobacteriaceae produce an extracellular matrix consisting of curli amyloid fibers and cellulose. The precursor of curli fibers is the amyloidogenic protein CsgA. The human systemic amyloid precursor protein transthyretin (TTR) is known to inhibit amyloid-β (Aβ) aggregation in vitro and suppress the Alzheimer's-like phenotypes in a transgenic mouse model of Aβ deposition. We hypothesized that TTR might have broad antiamyloid activity because the biophysical properties of amyloids are largely conserved across species and kingdoms. Here, we report that both human WT tetrameric TTR (WT-TTR) and its engineered nontetramer-forming monomer (M-TTR, F87M/L110M) inhibit CsgA amyloid formation in vitro, with M-TTR being the more efficient inhibitor. Preincubation of WT-TTR with small molecules that occupy the T4 binding site eliminated the inhibitory capacity of the tetramer; however, they did not significantly compromise the ability of M-TTR to inhibit CsgA amyloidogenesis. TTR also inhibited amyloid-dependent biofilm formation in two different bacterial species with no apparent bactericidal or bacteriostatic effects. These discoveries suggest that TTR is an effective antibiofilm agent that could potentiate antibiotic efficacy in infections associated with significant biofilm formation.}, } @article {pmid29086910, year = {2017}, author = {Casciaro, B and Dutta, D and Loffredo, MR and Marcheggiani, S and McDermott, AM and Willcox, MD and Mangoni, ML}, title = {Esculentin-1a derived peptides kill Pseudomonas aeruginosa biofilm on soft contact lenses and retain antibacterial activity upon immobilization to the lens surface.}, journal = {Biopolymers}, volume = {}, number = {}, pages = {}, doi = {10.1002/bip.23074}, pmid = {29086910}, issn = {1097-0282}, abstract = {Contact lens (CL) wear is a risk factor for development of microbial keratitis, a vision threatening infection of the eye. Adverse events associated with colonization of lenses, especially by the multi-drug resistant and biofilm forming bacterium Pseudomonas aeruginosa remain a major safety issue. Therefore, novel strategies and compounds to reduce the onset of CL-associated ocular infections are needed. Recently, the activity of the frog skin-derived antimicrobial peptide Esc(1-21) and its diastereomer Esc(1-21)-1c was evaluated against both planktonic and sessile forms of this pathogen. Furthermore, Esc(1-21) was found to significantly reduce the severity of P. aeruginosa keratitis in a mouse model and preserve antipseudomonal activity in the presence of human basal tears. Here, we have analyzed the activity of the peptides on P. aeruginosa biofilm formed on soft CLs. Microbiological assays and scanning electron microscopy analysis indicated that the peptides were able to disrupt the bacterial biofilm, with the diastereomer having the greater efficacy (up to 85% killing vs no killing at 4 μM for some strains). Furthermore, upon covalent immobilization to the CL, the two peptides were found to cause more than four log reduction in the number of bacterial cells within 20 minutes and to reduce bacterial adhesion to the CL surface (77%-97% reduction) in 24 hours. Importantly, peptide immobilization was not toxic to mammalian cells and did not affect the lens characteristics. Overall, our data suggest that both peptides have great potential to be developed as novel pharmaceuticals for prevention and treatment of CL-associated P. aeruginosa keratitis.}, } @article {pmid29085811, year = {2017}, author = {Manoharan, RK and Lee, JH and Kim, YG and Lee, J}, title = {Alizarin and Chrysazin Inhibit Biofilm and Hyphal Formation by Candida albicans.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {447}, pmid = {29085811}, issn = {2235-2988}, mesh = {Animals ; Anthraquinones/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans ; Candida albicans/*drug effects/genetics/pathogenicity ; Fluconazole/pharmacology ; Gene Expression Profiling ; Gene Expression Regulation, Fungal/drug effects ; Hyphae/*drug effects/genetics/pathogenicity ; Virulence/drug effects ; }, abstract = {Candida albicans is one of the most common pathogen causes fungal infections. This opportunistic pathogen can form biofilms comprised of yeast, hyphae and pseudo hyphal elements, and the hyphal form C. albicans considered as probable virulence factor. We investigated the antibiofilm activities of 13 quinones and anthraquinones related compounds against C. albicans biofilms by using crystal violet and 2,3-bis (2-Methoxy-4-Nitro-5-Sulfo-phenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) reduction assays to assess inhibitions of biofilm growth. Morphological changes in biofilms and biofilm thicknesses were determined by scanning electron microscopy and confocal laser scanning microscopy, respectively. It was found alizarin (1,2-dihydroxyanthraquinone) and chrysazin (1,8-dihydroxyanthraquinone) suppressed C. albicans biofilm formation. Interestingly, alizarin and chrysazin at only 2 μg/ml effectively inhibited hyphal formation and prolonged the survival of C. albicans infected Caenorhabditis elegans, thus showing a distinct antivirulent potential. A structural activity relationship study of alizarin and 6 other anthraquinones showed the presence of a hydroxyl group at C-1 position which is important for antibiofilm and antifilamentation activities. Transcriptomic analyses revealed that alizarin downregulated the expression of several hypha-specific and biofilm related genes (ALS3, ECE1, ECE2, and RBT1). Furthermore, unlike the commercial antifungal drug fluconazole, no acute toxic effect was observed when uninfected nematodes were exposed to alizarin at concentrations up to 1 mg/ml. The results of this study indicate alizarin suppresses the virulence of C. albicans in vivo which suggests alizarin may be considered as a potential candidate for further investigations to develop antifungal agent against fungal pathogen in vivo.}, } @article {pmid29085575, year = {2017}, author = {Fallah, A and Rezaee, MA and Hasani, A and Barhaghi, MHS and Kafil, HS}, title = {Frequency of bap and cpaA virulence genes in drug resistant clinical isolates of Acinetobacter baumannii and their role in biofilm formation.}, journal = {Iranian journal of basic medical sciences}, volume = {20}, number = {8}, pages = {849-855}, pmid = {29085575}, issn = {2008-3866}, abstract = {OBJECTIVES: Acinetobacter baumannii has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of bap and cpaA genes in biofilm formation by A. baumannii to understand how this pathogen persists in the hospital environment.

MATERIALS AND METHODS: The antibiotic resistance profile and invitro biofilm-forming ability of one hundred clinical isolates of A. baumannii was evaluated by disc diffusion and crystal-violet staining methods, respectively. Isolates were tested for the presence of bap and cpaA genes.

RESULTS: The isolates were highly resistant to cefepime, third-generation cephalosporins, ciprofloxacin, cotrimoxazole, aminoglycosides and carbapenems. Moreover, four isolates were resistant to colistin. Quantification of biofilm showed that 43% of the isolates were strong biofilm-producer. Furthermore, 32% of the isolates exhibited moderate biofilm-formation and showed initial binding activity. Frequency of bap and cpaA were determined 92% and 36%, respectively.

CONCLUSION: There was strong association between the presence of bap gene and biofilm formation by A. baumannii isolates (P=0.003). In addition, multidrug resistant isolates produced stronger biofilm than other isolates (P=0.0001). These results indicate importance of biofilm in resistance of isolates and effect of presence of bap gene in biofilm formation by A. baumannii strains.}, } @article {pmid29085354, year = {2017}, author = {Águila-Arcos, S and Álvarez-Rodríguez, I and Garaiyurrebaso, O and Garbisu, C and Grohmann, E and Alkorta, I}, title = {Biofilm-Forming Clinical Staphylococcus Isolates Harbor Horizontal Transfer and Antibiotic Resistance Genes.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2018}, pmid = {29085354}, issn = {1664-302X}, abstract = {Infections caused by staphylococci represent a medical concern, especially when related to biofilms located in implanted medical devices, such as prostheses and catheters. Unfortunately, their frequent resistance to high doses of antibiotics makes the treatment of these infections a difficult task. Moreover, biofilms represent a hot spot for horizontal gene transfer (HGT) by bacterial conjugation. In this work, 25 biofilm-forming clinical staphylococcal isolates were studied. We found that Staphylococcus epidermidis isolates showed a higher biofilm-forming capacity than Staphylococcus aureus isolates. Additionally, horizontal transfer and relaxase genes of two common staphylococcal plasmids, pSK41 and pT181, were detected in all isolates. In terms of antibiotic resistance genes, aac6-aph2a, ermC, and tetK genes, which confer resistance to gentamicin, erythromycin, and tetracycline, respectively, were the most prevalent. The horizontal transfer and antibiotic resistance genes harbored on these staphylococcal clinical strains isolated from biofilms located in implanted medical devices points to the potential risk of the development and dissemination of multiresistant bacteria.}, } @article {pmid29085341, year = {2017}, author = {Gao, JX and Li, P and Du, XJ and Han, ZH and Xue, R and Liang, B and Wang, S}, title = {A Negative Regulator of Cellulose Biosynthesis, bcsR, Affects Biofilm Formation, and Adhesion/Invasion Ability of Cronobacter sakazakii.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1839}, pmid = {29085341}, issn = {1664-302X}, abstract = {Cronobacter sakazakii is an important foodborne pathogen that causes neonatal meningitis and sepsis, with high mortality in neonates. However, very little information is available regarding the pathogenesis of C. sakazakii at the genetic level. In our previous study, a cellulose biosynthesis-related gene (bcsR) was shown to be involved in C. sakazakii adhesion/invasion into epithelial cells. In this study, the detailed functions of this gene were investigated using a gene knockout technique. A bcsR knockout mutant (ΔbcsR) of C. sakazakii ATCC BAA-894 showed decreased adhesion/invasion (3.9-fold) in human epithelial cell line HCT-8. Biofilm formation by the mutant was reduced to 50% of that exhibited by the wild-type (WT) strain. Raman spectrometry was used to detect variations in biofilm components caused by bcsR knockout, and certain components, including carotenoids, fatty acids, and amides, were significantly reduced. However, another biofilm component, cellulose, was increased in ΔbcsR, suggesting that bcsR negatively affects cellulose biosynthesis. This result was also verified via RT-PCR, which demonstrated up-regulation of five crucial cellulose synthesis genes (bcsA, B, C, E, Q) in ΔbcsR. Furthermore, the expression of other virulence or biofilm-related genes, including flagellar assembly genes (fliA, C, D) and toxicity-related genes (ompA, ompX, hfq), was studied. The expression of fliC and ompA in the ΔbcsR mutant was found to be remarkably reduced compared with that in the wild-type and the others were also affected excepted ompX. In summary, bcsR is a negative regulator of cellulose biosynthesis but positively regulates biofilm formation and the adhesion/invasion ability of C. sakazakii.}, } @article {pmid29085129, year = {2017}, author = {Vázquez-Sánchez, D and Galvão, JA and Oetterer, M}, title = {Contamination sources, serogroups, biofilm-forming ability and biocide resistance of Listeria monocytogenes persistent in tilapia-processing facilities.}, journal = {Journal of food science and technology}, volume = {54}, number = {12}, pages = {3867-3879}, pmid = {29085129}, issn = {0022-1155}, abstract = {The major contamination sources, serogroups, biofilm-forming ability and biocide resistance of Listeria monocytogenes persistent in tilapia-processing facilities were assessed. Twenty-five processing-control points were examined twice in two factories, including whole tilapias, frozen fillets, water and food-contact surfaces. L. monocytogenes were detected in 4 and 20% of points of Factory A and B respectively, but at low concentrations. Contamination was due to inadequate handling of tilapias in the slaughter room of Factory A and to the application of ineffective sanitizing procedures in Factory B. Seven strains were characterized by RAPD-PCR using primers HLWL85, OPM-01 and DAF4. Genotypic similarity allowed tracing the contamination source of tilapia fillets in Factory B and detecting a prevalent strain in Brazilian tilapia-processing facilities. The serogroup II (including the serotype 1/2c) was the most frequently found, followed by serogroup I (1/2a) and III (1/2b), whereas the serotype 4b was not detected. All strains showed high biofilm-forming ability on stainless steel and polystyrene, but biofilm formation was positively correlated with the type of origin surface. Biofilms were highly resistant to peracetic acid and sodium hypochlorite, being required doses higher than those recommended by manufacturers to be eradicated. Peracetic acid was more effective than sodium hypochlorite, but the use of disinfectants with similar mechanisms of action increases the risk of cross-resistance. Case-by-case approaches are thus recommended to determine the sources and degree of contamination present in each factory, which would allow applying precise responses to control the persistence of bacterial pathogens such as L. monocytogenes.}, } @article {pmid29085075, year = {2018}, author = {Vidakovic, L and Singh, PK and Hartmann, R and Nadell, CD and Drescher, K}, title = {Dynamic biofilm architecture confers individual and collective mechanisms of viral protection.}, journal = {Nature microbiology}, volume = {3}, number = {1}, pages = {26-31}, pmid = {29085075}, issn = {2058-5276}, support = {716734/ERC_/European Research Council/International ; }, mesh = {Bacteriophage T7/physiology ; Biofilms/*growth & development ; Escherichia coli/growth & development/*physiology/virology ; Escherichia coli Proteins/genetics/*metabolism ; Extracellular Matrix/genetics/*metabolism ; Kinetics ; Single-Cell Analysis ; }, abstract = {In nature, bacteria primarily live in surface-attached, multicellular communities, termed biofilms [1-6] . In medical settings, biofilms cause devastating damage during chronic and acute infections; indeed, bacteria are often viewed as agents of human disease [7] . However, bacteria themselves suffer from diseases, most notably in the form of viral pathogens termed bacteriophages [8-12] , which are the most abundant replicating entities on Earth. Phage-biofilm encounters are undoubtedly common in the environment, but the mechanisms that determine the outcome of these encounters are unknown. Using Escherichia coli biofilms and the lytic phage T7 as models, we discovered that an amyloid fibre network of CsgA (curli polymer) protects biofilms against phage attack via two separate mechanisms. First, collective cell protection results from inhibition of phage transport into the biofilm, which we demonstrate in vivo and in vitro. Second, CsgA fibres protect cells individually by coating their surface and binding phage particles, thereby preventing their attachment to the cell exterior. These insights into biofilm-phage interactions have broad-ranging implications for the design of phage applications in biotechnology, phage therapy and the evolutionary dynamics of phages with their bacterial hosts.}, } @article {pmid29082887, year = {2018}, author = {Krzyżek, P and Gościniak, G}, title = {A proposed role for diffusible signal factors in the biofilm formation and morphological transformation of Helicobacter pylori.}, journal = {The Turkish journal of gastroenterology : the official journal of Turkish Society of Gastroenterology}, volume = {29}, number = {1}, pages = {7-13}, pmid = {29082887}, issn = {2148-5607}, mesh = {Bacterial Proteins/*physiology ; Biofilms/*growth & development ; Carrier Proteins/physiology ; Escherichia coli Proteins/physiology ; Helicobacter Infections/*microbiology ; Helicobacter pylori/*physiology ; Humans ; }, abstract = {Due to the increasing resistance of Helicobacter pylori to antibiotics, there is a growing need for new strategies for the effective eradication of this pathogen. The inhibition of quorum-sensing activity in most microorganisms leads to a decrease in virulence. A different reaction is observed in H. pylori, as interfering with the production of autoinducer-2 initiates biofilm formation and increases the survival of these bacteria. Therefore, it is believed that there is an alternative way to control the physiological changes of H. pylori exposed to environmental stress. In this article, we present the compounds probably involved in the modulation of H. pylori virulence. Diffusible signal factors (DSFs) are fatty acid signal molecules involved in communication between microbes. DSFs are likely to stimulate H. Pylori transition into a sedentary state that correlates with bacterial transformation into a more resistant coccoid form and initiates biofilm formation. Biofilm is a structure that plays a crucial role in protecting against adverse environmental factors (low pH, oxidative stress, action of immune system) and limiting the effective concentration of antimicrobial substances. This article has suggested and characterized the existence of an alternative DSF-mediated cell-cell signaling of H. pylori, which controls autoaggregative behaviors, biofilm formation, and the transition of microorganisms into the coccoid form.}, } @article {pmid29081917, year = {2017}, author = {Panariello, BHD and Klein, MI and Pavarina, AC and Duarte, S}, title = {Inactivation of genes TEC1 and EFG1 in Candida albicans influences extracellular matrix composition and biofilm morphology.}, journal = {Journal of oral microbiology}, volume = {9}, number = {1}, pages = {1385372}, pmid = {29081917}, issn = {2000-2297}, abstract = {Background: Infections caused by Candida spp. have been associated with formation of a biofilm, i.e. a complex microstructure of cells adhering to a surface and embedded within an extracellular matrix (ECM). Methods: The ECMs of a wild-type (WT, SN425) and two Candida albicans mutant strains, Δ/Δ tec1 (CJN2330) and Δ/Δ efg1 (CJN2302), were evaluated. Colony-forming units (cfu), total biomass (mg), water-soluble polysaccharides (WSPs), alkali-soluble polysaccharides (ASPs), proteins (insoluble part of biofilms and matrix proteins), and extracellular DNA (eDNA) were quantified. Variable-pressure scanning electron microscopy and confocal scanning laser microscopy were performed. The biovolume (μm[3]/μm[2]) and maximum thickness (μm) of the biofilms were quantified using COMSTAT2. Results: ASP content was highest in WT (mean ± SD: 74.5 ± 22.0 µg), followed by Δ/Δ tec1 (44.0 ± 24.1 µg) and Δ/Δ efg1 (14.7 ± 5.0 µg). The protein correlated with ASPs (r = 0.666) and with matrix proteins (r = 0.670) in the WT strain. The population in Δ/Δ efg1 correlated with the protein (r = 0.734) and its biofilms exhibited the lowest biomass and biovolume, and maximum thickness. In Δ/Δ tec1, ASP correlated with eDNA (r = 0.678). Conclusion: ASP production may be linked to C. albicans cell filamentous morphology.}, } @article {pmid29081612, year = {2017}, author = {Singh, G and Kulharia, M}, title = {Insights from the analysis of alginate lyase protein model from Pseudomonas fluorescens towards the understanding of mucoid biofilm disruption.}, journal = {Bioinformation}, volume = {13}, number = {9}, pages = {318-322}, pmid = {29081612}, issn = {0973-2063}, abstract = {Bacterial biofilm is a protective, slippery and slimy coat secreted by bacterial cells. It helps in attaching to moisturized surfaces during colonization. Alginate is an important component as it is essential for retention of water and nutrients in biofilms. It is a polysaccharide consisting of β-D-mannuronic acid (M) and α-L-guluronic acid (G) monomers with 1-4 linkage. The alginate lyase (AlgL) secreted by certain bacteria is capable of degrading alginate into oligo-uronides by β-elimination of the glycosidic bond. Therefore, it is of interest to analyze the simulated (GROMACS force filed) structure protein model (homology based on template 4OZV) of AlgL from Pseudomonas fluorescens to gain functional insight mucoid biofilm disruption. We report root mean square deviation (RMSD) and radius of gyration (Rg) profiles of the simulated (molecular dynamics) AlgL protein homology model in this context towards biofilm discruption.}, } @article {pmid29079976, year = {2018}, author = {Laganà, P and Votano, L and Caruso, G and Azzaro, M and Lo Giudice, A and Delia, S}, title = {Bacterial isolates from the Arctic region (Pasvik River, Norway): assessment of biofilm production and antibiotic susceptibility profiles.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {2}, pages = {1089-1102}, pmid = {29079976}, issn = {1614-7499}, support = {Interact project//FP7/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Arctic Regions ; Bacteria/isolation & purification ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Environment ; Norway ; Rivers/*microbiology ; }, abstract = {Bacterial biofilm production is recognized as a strategy that helps aquatic bacteria in resisting to the presence of several kinds of pollutants, including antibiotics, in the bulk environment. The Pasvik River, located between Norway, Russia and Finland, is a sub-Arctic site polluted by wastes from metallurgic and mining activities. In order to study whether and to what extent bacteria are able to produce biofilms, and to assess whether this physiological characteristic influences their resistance to antibiotics, an investigation was performed on bacteria isolated from water and sediment collected along the Pasvik River course during two surveys (May and July). Bacterial strains were screened for their biofilm production and profiles of susceptibility to antibiotics. Results showed that biofilm formation was a widespread characteristic of the isolates. Most of them were also resistant to several antibiotics, such as ampicillin (100% of the isolates) as well as cefazolin, cefoxitin, ceftriaxone, mezlocillin, nitrofurantoin and sisomicin (90% of the total strains). This study shows a significant association between biofilm formation and antibiotic resistance at inner stations both in water and in sediments in May only. This suggests that in Pasvik River colder temperature may stimulate bacterial aggregation into biofilm and simultaneously decrease bacterial susceptibility to antibiotics; since the occurrence of antibiotic resistance has frequently been linked to the presence of pollutants, this result could represent a strategy of bacterial survival under altered environmental conditions.}, } @article {pmid29076756, year = {2017}, author = {Xu, Y and Tong, X and Sun, P and Bi, L and Lin, K}, title = {Virtual screening and biological evaluation of biofilm inhibitors on dual targets in quorum sensing system.}, journal = {Future medicinal chemistry}, volume = {9}, number = {17}, pages = {1983-1994}, doi = {10.4155/fmc-2017-0127}, pmid = {29076756}, issn = {1756-8927}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/*agonists/*antagonists & inhibitors ; Biofilms/*drug effects ; Drug Evaluation, Preclinical ; Microbial Sensitivity Tests ; Models, Molecular ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Repressor Proteins/*agonists ; Structure-Activity Relationship ; Trans-Activators/*antagonists & inhibitors ; }, abstract = {AIM: Resistance to conventional antibiotics has spurred interest in exploring new antimicrobial strategies. Suppressing quorum sensing within biofilm is a promising antimicrobial strategy. LasR in quorum sensing system of the Gram-negative bacteria, Pseudomonas aeruginosa, directly enhances virulence and antibiotic resistance, with QscR as its indirect suppressor, so targeting both of them can synergistically take the effect.

METHODOLOGY/RESULTS: An in silico protocol combining pharmacophores with molecular docking was applied. Pharmacophores of QscR agonists and LasR antagonists were prepared for preliminary screening, followed by counter-screen using a pharmacophore model of LasR agonists and molecular docking of LasR. Four compounds with novel scaffolds were confirmed as potential biofilm inhibitors with preliminary experimental data.

CONCLUSION: Novel biofilm inhibitors can be found with the method.}, } @article {pmid29075628, year = {2017}, author = {Feng, J and Zhang, S and Shi, W and Zubcevik, N and Miklossy, J and Zhang, Y}, title = {Selective Essential Oils from Spice or Culinary Herbs Have High Activity against Stationary Phase and Biofilm Borrelia burgdorferi.}, journal = {Frontiers in medicine}, volume = {4}, number = {}, pages = {169}, pmid = {29075628}, issn = {2296-858X}, support = {R01 AI099512/AI/NIAID NIH HHS/United States ; R21 AI108535/AI/NIAID NIH HHS/United States ; }, abstract = {Although the majority of patients with acute Lyme disease can be cured with the standard 2-4 week antibiotic treatment, about 10-20% of patients continue suffering from chronic symptoms described as posttreatment Lyme disease syndrome. While the cause for this is debated, one possibility is that persister bacteria are not killed by the current Lyme antibiotics and remain active in the system. It has been reported that essential oils have antimicrobial activities and some have been used by patients with persisting Lyme disease symptoms. However, the activity of essential oils against the causative agent Borrelia burgdorferi (B. burgdorferi) has not been well studied. Here, we evaluated the activity of 34 essential oils against B. burgdorferi stationary phase culture as a model for persister bacteria. We found that not all essential oils had activity against the B. burgdorferi stationary phase culture, with top five essential oils (oregano, cinnamon bark, clove bud, citronella, and wintergreen) at a low concentration of 0.25% showing high anti-persister activity that is more active than the known persister drug daptomycin. Interestingly, some highly active essential oils were found to have excellent anti-biofilm ability as shown by their ability to dissolve the aggregated biofilm-like structures. The top three hits, oregano, cinnamon bark, and clove bud completely eradicated all viable cells without any regrowth in subculture in fresh medium, whereas but not citronella and wintergreen did not have this effect. Carvacrol was found to be the most active ingredient of oregano oil showing excellent activity against B. burgdorferi stationary phase cells, while other ingredients of oregano oil p-cymene and α-terpinene had no apparent activity. Future studies are needed to characterize and optimize the active essential oils in drug combination studies in vitro and in vivo and to address their safety and pharmacokinetic properties before they can be considered as a novel treatment of persistent Lyme disease.}, } @article {pmid29075407, year = {2017}, author = {Jaiswal, N and Sinha, DJ and Singh, UP and Singh, K and Jandial, UA and Goel, S}, title = {Evaluation of antibacterial efficacy of Chitosan, Chlorhexidine, Propolis and Sodium hypochlorite on Enterococcus faecalis biofilm : An in vitro study.}, journal = {Journal of clinical and experimental dentistry}, volume = {9}, number = {9}, pages = {e1066-e1074}, pmid = {29075407}, issn = {1989-5488}, abstract = {BACKGROUND: Long term successful root canal treatment requires effective debridement and disinfection of root canal system. Persistent periradicular lesions are usually associated with Enterococccus faecalis. Prompt research for natural alternatives for irrigation is mainly due to the constant increase in antibiotic resistant strains and side effects caused by synthetic drugs. Sodium hypochlorite; the gold standard for irrigation has many disadvantages. Therefore, the present study was aimed to explore newer irrigants probably be as more effective and at the same time would be less irritating to the tissues than NaOCl.

MATERIAL AND METHODS: Ninety extracted human mandibular premolars were biomechanically prepared, vertically sectioned, placed in tissue culture wells exposing the root canal surface to E. faecalis to form a biofilm. At the end of 3rd week, all groups were irrigated with 3 ml of test solutions and control for 10 minutes. The samples were then scraped with a scalpel, inoculated on tryptone soy agar plates and incubated for 24 hours at 37ºC. The plates were then subjected to digital colony counter and evaluated for E. faecalisgrowth. The growth was statistically analysed by ANOVA & Post Hoc Tukey tests.

RESULTS: Chitosan + Chlorhexidine, NaOCl and Chlorhexidine showed no statistically significant difference, whereas all the other inter‑group differences were statistically significant (P<0.05).

CONCLUSIONS: Chitosan + Chlorhexidine, Chlorhexidine and Propolis were found to be as efficacious as sodium hypochlorite. The use of natural alternatives as root canal irrigation solutions might prove to be advantageous considering several unfavorable properties of NaOCl. Key words:Antibacterial efficacy, Chitosan, Enterococcus faecalis, Root canal irrigation.}, } @article {pmid29075113, year = {2017}, author = {Alhariri, M and Majrashi, MA and Bahkali, AH and Almajed, FS and Azghani, AO and Khiyami, MA and Alyamani, EJ and Aljohani, SM and Halwani, MA}, title = {Efficacy of neutral and negatively charged liposome-loaded gentamicin on planktonic bacteria and biofilm communities.}, journal = {International journal of nanomedicine}, volume = {12}, number = {}, pages = {6949-6961}, pmid = {29075113}, issn = {1178-2013}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/chemistry/*pharmacology ; Biofilms/drug effects ; Gentamicins/administration & dosage/chemistry/*pharmacology ; Humans ; Klebsiella oxytoca/drug effects ; Liposomes/*chemistry/pharmacology ; Male ; Microbial Sensitivity Tests ; Nanoparticles ; Particle Size ; Plankton/*microbiology ; Pseudomonas aeruginosa/drug effects ; Rats ; }, abstract = {We investigated the efficacy of liposomal gentamicin formulations of different surface charges against Pseudomonas aeruginosa and Klebsiella oxytoca. The liposomal gentamicin formulations were prepared by the dehydration-rehydration method, and their sizes and zeta potential were measured. Gentamicin encapsulation efficiency inside the liposomal formulations was determined by microbiologic assay, and stability of the formulations in biologic fluid was evaluated for a period of 48 h. The minimum inhibitory concentration and the minimum bactericidal concentration were determined, and the in vitro time kill studies of the free form of gentamicin and liposomal gentamicin formulations were performed. The activities of liposomal gentamicin in preventing and reducing biofilm-forming P. aeruginosa and K. oxytoca were compared to those of free antibiotic. The sizes of the liposomal formulations ranged from 625 to 806.6 nm in diameter, with the zeta potential ranging from -0.22 to -31.7 mV. Gentamicin encapsulation efficiency inside the liposomal formulation ranged from 1.8% to 43.6%. The liposomes retained >60% of their gentamicin content during the 48 h time period. The minimum inhibitory concentration of neutral formulation was lower than that of free gentamicin (0.25 versus 1 mg/L for P. aeruginosa and 0.5 versus 1 mg/L for K. oxytoca). The negatively charged formulation exhibited the same bacteriostatic concentration as that of free gentamicin. The minimum bactericidal concentration of neutral liposomes on planktonic bacterial culture was twofold lower than that of free gentamicin, whereas the negatively charged formulations were comparable to free gentamicin. The killing time curve values for the neutral negatively charged formulation against planktonic P. aeruginosa and K. oxytoca were better than those of free gentamicin. Furthermore, liposomal formulations prevent the biofilm-formation ability of these strains better than free gentamicin. In summary, liposomal formulations could be an effective lipid nanoparticle to combat acute infections where planktonic bacteria are predominant.}, } @article {pmid29074435, year = {2017}, author = {Behbehani, J and Shreaz, S and Irshad, M and Karched, M}, title = {The natural compound magnolol affects growth, biofilm formation, and ultrastructure of oral Candida isolates.}, journal = {Microbial pathogenesis}, volume = {113}, number = {}, pages = {209-217}, doi = {10.1016/j.micpath.2017.10.040}, pmid = {29074435}, issn = {1096-1208}, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Biphenyl Compounds/chemistry/*pharmacology ; Candida/cytology/*drug effects/growth & development/isolation & purification ; Candidiasis, Oral/*drug therapy ; Cell Membrane/drug effects ; Ergosterol/pharmacology ; Erythrocytes/drug effects ; Humans ; Lignans/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Microscopy ; Molecular Docking Simulation ; }, abstract = {The incidence of oral candidosis has increased in recent years due to the escalation in HIV-infection, cancer treatments, organ transplantation, and diabetes. In addition, corticosteroid use, dentures, and broad-spectrum antibiotic use have also contributed to the problem. Treatment of oral candidosis has continued to be problematic because of the potential toxicity of antifungals in clinical use, and, above all, development of drug resistance among patients. In this study, the antifungal effect of magnolol was investigated against 64 strains of Candida spp. (four standard and 60 oral isolates) through minimum inhibitory concentration (MIC) and growth curve assays. Insight into the mechanisms of the antifungal action has been gained through ultrastructural studies using confocal scanning laser microscopy (CSLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Molecular docking was done for predicting the interactions of magnolol with ergosterol at supramolecular level. The toxicity of magnolol on human erythrocytes was measured by in vitro hemolytic assay. MIC values of magnolol ranged from 16-64 μg/ml, respectively. All tested isolates showed a marked sensitivity towards magnolol in growth curve assays. Biofilm results suggested that magnolol showed strong anti-biofilm activity. The results obtained for four different Candida spp. demonstrated that MBIC values of magnolol showed the average biofilm inhibition by 69.5%, respectively. CLSM experiments showed that cells exposed to magnolol (MIC) exhibited cell membrane disruption. SEM analysis of magnolol treated cells resulted in deformed cells. TEM micrographs showed rupturing of the cell wall and plasma membrane, releasing the intracellular content, and swelling of the cell wall. Hemolytic activity of magnolol is 11.9% at its highest MIC compared to an activity level of 25.4% shown by amphotericin B (Amp B) at 1 μg/ml. Lipinski's parameters calculated for magnolol suggested its good oral bioavailability. Docking studies indicated that magnolol might be interacting with ergosterol in the fungal cell membranes. Together, the present study provides enough evidence for further work on magnolol so that better strategies could be employed to treat oral candidosis.}, } @article {pmid29071242, year = {2017}, author = {Centorame, P and D'Angelo, AR and Simone, FD and Salini, R and Cornacchia, A and Marrone, R and Anastasio, A and Pomilio, F}, title = {Listeria monocytogenes biofilm production on food packaging materials submitted to physical treatment.}, journal = {Italian journal of food safety}, volume = {6}, number = {3}, pages = {6654}, pmid = {29071242}, issn = {2239-7132}, } @article {pmid29069969, year = {2019}, author = {Trojanowicz, K and Plaza, E and Trela, J}, title = {Model extension, calibration and validation of partial nitritation-anammox process in moving bed biofilm reactor (MBBR) for reject and mainstream wastewater.}, journal = {Environmental technology}, volume = {40}, number = {9}, pages = {1079-1100}, doi = {10.1080/09593330.2017.1397765}, pmid = {29069969}, issn = {1479-487X}, mesh = {*Biofilms ; Bioreactors ; Calibration ; Nitrogen ; Oxidation-Reduction ; *Wastewater ; }, abstract = {In the paper, the extension of mathematical model of partial nitritation-anammox process in a moving bed biofilm reactor (MBBR) is presented. The model was calibrated with a set of kinetic, stoichiometric and biofilm parameters, whose values were taken from the literature and batch tests. The model was validated with data obtained from: laboratory batch experiments, pilot-scale MBBR for a reject water deammonification operated at Himmerfjärden wastewater treatment and pilot-scale MBBR for mainstream wastewater deammonification at Hammarby Sjöstadsverk research facility, Sweden. Simulations were conducted in AQUASIM software. The proposed, extended model proved to be useful for simulating of partial nitritation/anammox process in biofilm reactor both for reject water and mainstream wastewater at variable substrate concentrations (influent total ammonium-nitrogen concentration of 530 ± 68; 45 ± 2.6 and 38 ± 3 gN/m[3] - for reject water - and two cases of mainstream wastewater treatment, respectively), temperature (24 ± 2.8; 15 ± 1.1 and 18 ± 0.5°C), pH (7.8 ± 0.2; 7.3 ± 0.1 and 7.4 ± 0.1) and aeration patterns (continuous aeration and intermittent aeration with variable dissolved oxygen concentrations and length of aerated and anoxic phases). The model can be utilized for optimizing and testing different operational strategies of deammonification process in biofilm systems.}, } @article {pmid29069404, year = {2017}, author = {Li, T and Strous, M and Melkonian, M}, title = {Biofilm-based photobioreactors: their design and improving productivity through efficient supply of dissolved inorganic carbon.}, journal = {FEMS microbiology letters}, volume = {364}, number = {24}, pages = {}, doi = {10.1093/femsle/fnx218}, pmid = {29069404}, issn = {1574-6968}, mesh = {*Biofilms ; Carbon/*metabolism ; Equipment Design ; *Photobioreactors ; }, abstract = {The potential of biofilm-based photobioreactors (PBRs) for various applications has long been recognized, and various types of biofilm-based PBRs have been developed for different applications. Compared to suspension-based PBR reactors, biofilm-based systems offer several advantages, including a significantly higher biomass concentration. However, due to the immobilization of the cells, in contrast to suspension-based systems, dissolved inorganic carbon (DIC) has to be transferred into the biofilm for consumption. Thus, to ensure efficient operation of these systems under a given lighting scheme (e.g. depending on geographical location), availability of DIC should be optimized. To achieve this, the dynamics of DIC inside the various biofilm-based PBRs, as well as the operational principles of these PBRs, need to be understood. The mini-review summarizes the designs of existing biofilm-based PBRs and reviews previous studies on DIC dynamics in various biofilms. Strategies to enhance DIC availability for the immobilized cells in biofilm-based PBRs are also discussed.}, } @article {pmid29068919, year = {2017}, author = {Danino, MA and Nizard, N and Paek, LS and Govshievich, A and Giot, JP}, title = {Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.}, journal = {Plastic and reconstructive surgery}, volume = {140}, number = {5}, pages = {878-883}, doi = {10.1097/PRS.0000000000003767}, pmid = {29068919}, issn = {1529-4242}, mesh = {Adult ; *Biofilms ; Breast Implantation/instrumentation/methods ; Breast Implants/*microbiology ; Female ; Foreign-Body Reaction/*microbiology/pathology ; Humans ; Microscopy, Electron, Scanning ; Middle Aged ; Postoperative Complications/*microbiology/pathology ; Prospective Studies ; Tissue Expansion/instrumentation ; Tissue Expansion Devices/*microbiology ; }, abstract = {BACKGROUND: The double capsule is a complication mostly described in aggressive macrotextured implants. Mechanical shear stress applied onto an immature periprosthetic capsule has been linked to their formation. The authors aim to demonstrate the role of bacterial phenotype and biofilm in the development of the double capsule.

METHODS: Seven double capsules formed at the interface of macrotextured breast expander implants were studied using scanning electron microscopy. Two samples for each surface of the inner capsule layer (the prosthesis interface and the intercapsular space) were analyzed for bacteria cell size, bacterial density, and biofilm deposition.

RESULTS: Although all routine bacterial cultures were negative, the prosthesis interface had both higher bacteria load and biofilm deposition compared with the intercapsular space (Mann-Whitney U test, p = 0.004 and p = 0.008, respectively). Moreover, bacteria cell sizes were significantly smaller at the prosthesis interface in six of seven samples. Comparison of bacteria density and biofilm dispersion showed an increase of biofilm extracellular matrix deposition over 2000 cells/mm (linear regression, p = 0.0025). These results indicate a common trend among bacteria species.

CONCLUSIONS: Bacterial expression between the different surfaces of the double capsule displays significant differences; bacteria at the prosthesis interface are mostly in a biofilm state, whereas they demonstrate a planktonic phenotype at the intercapsular space. When a sufficient amount of bacteria are present at a specific location, quorum sensing may trigger a biofilm phenotypic switch in planktonic bacteria cells. Biofilm formation may alter capsule formation through immune response, thereby weakening capsule strength and facilitating extracellular matrix delamination and double-capsule formation.

Therapeutic, V.}, } @article {pmid29068284, year = {2017}, author = {Feirer, N and Kim, D and Xu, J and Fernandez, N and Waters, CM and Fuqua, C}, title = {The Agrobacterium tumefaciens CheY-like protein ClaR regulates biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {11}, pages = {1680-1691}, pmid = {29068284}, issn = {1465-2080}, support = {R01 GM080546/GM/NIGMS NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; R01 GM120337/GM/NIGMS NIH HHS/United States ; T32 GM007757/GM/NIGMS NIH HHS/United States ; }, abstract = {The switch from a motile, planktonic existence to an attached biofilm is a major bacterial lifestyle transition that is often mediated by complex regulatory pathways. In this report, we describe a CheY-like protein required for control of the motile-to-sessile switch in the plant pathogen Agrobacterium tumefaciens. This regulator, which we have designated ClaR, possesses two distinct CheY-like receiver (REC) domains and is involved in the negative regulation of biofilm formation, through production of the unipolar polysaccharide (UPP) adhesin and cellulose. The ClaR REC domains share predicted structural homology with characterized REC domains and contain the majority of active site residues known to be essential for protein phosphorylation. REC1 is missing the conserved aspartate (N72) residue and although present in REC 2 (D193), it is not required for ClaR-dependent regulation suggesting that phosphorylation, which modulates the activity of many CheY-like proteins, appears not to be essential for ClaR activity. We also show that ClaR-dependent negative regulation of attachment is diminished significantly in mutants for PruA and PruR, proteins known to be involved in a pterin-mediated attachment regulation pathway. In A. tumefaciens, pterins are required for control of the intracellular signal cyclic diguanylate monophosphate through the DcpA regulator, but our findings suggest that pterin-dependent ClaR control of attachment can function independently from DcpA, including dampening of c-di-GMP levels. This report of a novel CheY-type biofilm regulator in A. tumefaciens thus also adds significant details to the role of pterin-mediated signalling.}, } @article {pmid29067567, year = {2017}, author = {Khelissa, SO and Jama, C and Abdallah, M and Boukherroub, R and Faille, C and Chihib, NE}, title = {Effect of incubation duration, growth temperature, and abiotic surface type on cell surface properties, adhesion and pathogenicity of biofilm-detached Staphylococcus aureus cells.}, journal = {AMB Express}, volume = {7}, number = {1}, pages = {191}, pmid = {29067567}, issn = {2191-0855}, abstract = {The goal of this study was to investigate the effect of growth conditions such as the temperature (20, 30 and 37 °C), incubation duration (24 and 48 h) and surface type (stainless steel and polycarbonate) on the cell surface physicochemical properties and adhesion to abiotic surfaces of biofilm-detached and planktonic Staphylococcus aureus cells. This study tested also the hypothesis that S. aureus planktonic cells exhibit distinct pathogenic properties compared with their sessile counterparts. The results showed that the changes of the growth conditions promoted changes in the zeta potential, hydrophobicity, electron donor/acceptor character of the studied cell populations. Biofilm-detached cells showed a greater adhesion to stainless steel and polycarbonate compared with planktonic cells. Compared with planktonic cells, sessile ones showed higher cytotoxic effect against HeLa cells, DNase activity, and siderophore levels. The higher cytotoxic effect and production of DNase and siderophore increased with the increase of temperature and duration of incubations. Based on the obtained data, the S. aureus biofilm-detached cells were found to be distinct in many physiological properties compared with their planktonic counterparts.}, } @article {pmid29067482, year = {2018}, author = {Han, S and Shen, D and Zhao, Y and Xu, D and Liu, J and Chou, SH and Liu, F and Qian, G}, title = {Sigma factor RpoN employs a dual transcriptional regulation for controlling twitching motility and biofilm formation in Lysobacter enzymogenes OH11.}, journal = {Current genetics}, volume = {64}, number = {2}, pages = {515-527}, pmid = {29067482}, issn = {1432-0983}, support = {31572046//National Natural Science Foundation of China/ ; 31501589//National Natural Science Foundation of China/ ; }, mesh = {Antifungal Agents/therapeutic use ; *Biofilms ; Biological Control Agents/therapeutic use ; Gene Expression Regulation, Bacterial ; Lysobacter/*genetics ; Mutation ; RNA Polymerase Sigma 54/*genetics ; Sigma Factor/*genetics ; }, abstract = {Lysobacter is a Gram-negative genus comprising a group of environmental bacteria with abilities to produce abundant novel antibiotics, as well as adopting a unique type IV pilus (T4P)-mediated twitching motility (TM) that remains poorly understood. Here, we employ L. enzymogenes OH11 exhibiting significant antifungal activity as a working model to address this issue. Via mutating the 28 potential sigma factors in strain OH11, we have identified one protein RpoNOH11 (sigma 54) that is indispensable for T4P formation and TM. We further showed that RpoNOH11 not only regulates the transcription of pilA, but also another crucial gene chpA that encodes a hybrid two-component transduction system. The L. enzymogenes RpoNOH11 was found to directly bind to the promoter of chpA to control its transcription, which is found to be essential for the T4P-mediated TM. To our knowledge, such a transcriptional regulation performed by RpoN in control of bacterial TM has never been reported. Finally, we showed that L. enzymogenes OH11 could also produce biofilm that is likely employed by this strain to infect fungal pathogens. Mutation of rpoN OH11, pilA and chpA all led to a significant decrease in biofilm formation, suggesting that the dual transcriptional regulation of pilA and chpA by RpoNOH11 plays a key role for RpoNOH11 to modulate the biofilm formation in L. enzymogenes. Overall, this study identified chpA as a new target of RpoN for controlling the T4P-mediated twitching motility and biofilm formation in L. enzymogenes OH11.}, } @article {pmid29067019, year = {2017}, author = {Jensen, LK and Johansen, ASB and Jensen, HE}, title = {Porcine Models of Biofilm Infections with Focus on Pathomorphology.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1961}, pmid = {29067019}, issn = {1664-302X}, abstract = {Bacterial biofilm formation is one of the main reasons for a negative treatment outcome and a high recurrence rate for many chronic infections in humans. The optimal way to study both the biofilm forming bacteria and the host response simultaneously is by using discriminative, reliable, and reproducible animal models of the infections. In this review, the advantages of in vivo studies are compared to in vitro studies of biofilm formation in infectious diseases. The pig is the animal of choice when developing and applying large animal models of infectious diseases due to its similarity of anatomy, physiology, and immune system to humans. Furthermore, conventional pigs spontaneously develop many of the same chronic bacterial infections as seen in humans. Therefore, in this review porcine models of five different infectious diseases all associated with biofilm formation and chronicity in humans are described. The infectious diseases are: chronic wounds, endocarditis, pyelonephritis, hematogenous osteomyelitis, and implant-associated osteomyelitis (IAO).}, } @article {pmid29067011, year = {2017}, author = {Fan, X and Liang, M and Wang, L and Chen, R and Li, H and Liu, X}, title = {Aii810, a Novel Cold-Adapted N-Acylhomoserine Lactonase Discovered in a Metagenome, Can Strongly Attenuate Pseudomonas aeruginosa Virulence Factors and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1950}, pmid = {29067011}, issn = {1664-302X}, abstract = {The pathogen Pseudomonas aeruginosa uses quorum sensing (QS) to control virulence and biofilm formation. Enzymatic disruption of quorum sensing is a promising anti-infection therapeutic strategy that does not rely on antibiotics. Here, a novel gene (aii810) encoding an N-acylhomoserine lactonase was isolated from the Mao-tofu metagenome for the first time. Aii810 encoded a protein of 269 amino acids and was expressed in Escherichia coli BL21 (DE3) in soluble form. It showed the highest activity at 20°C, and it maintained 76.5% of activity at 0°C and more than 50% activity at 0-40°C. The optimal pH was 8.0. It was stable in both neutral and slightly alkaline conditions and at temperatures below 40°C. The enzyme hydrolyzed several ρ-nitrophenyl esters, but its best substrate was ρ-nitrophenyl acetate. Its kcat and Km values were 347.7 S[-1] and 205.1 μM, respectively. It efficiently degraded N-butyryl-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone, exceeding hydrolysis rates of 72.3 and 100%, respectively. Moreover, Aii810 strongly attenuated P. aeruginosa virulence and biofilm formation. This enzyme with high anti-QS activity was the most cold-adapted N-acylhomoserine lactonase reported, which makes it an attractive enzyme for use as a therapeutic agent against P. aeruginosa infection.}, } @article {pmid29067006, year = {2017}, author = {Xiros, C and Studer, MH}, title = {A Multispecies Fungal Biofilm Approach to Enhance the Celluloyltic Efficiency of Membrane Reactors for Consolidated Bioprocessing of Plant Biomass.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1930}, pmid = {29067006}, issn = {1664-302X}, abstract = {The constraints and advantages in cellulolytic enzymes production by fungal biofilms for a consolidated bioconversion process were investigated during this study. The biofilm cultivations were carried out in reactors designed for consolidated bioprocessing Multispecies Biofilm Membrane reactors, (MBM) where an aerobic fungal biofilm produces the lignocellulolytic enzymes while a fermenting microorganism forms the fermentation product at anaerobic conditions. It was shown that although mycelial growth was limited in the MBM reactors compared to submerged cultivations, the secretion of cellulolytic enzymes per cell dry weight was higher. When Trichoderma reesei was used as the sole enzyme producer, cellobiose accumulated in the liquid medium as the result of the deficiency of β-glucosidase in the fungal secretome. To enhance β-glucosidase activity, T. reesei was co-cultivated with A. phoenicis which is a β-glucosidase overproducer. The two fungi formed a multispecies biofilm which produced a balanced cellulolytic cocktail for the saccharification of plant biomass. The mixed biofilm reached a 2.5 fold increase in β-glucosidase production, compared to the single T. reesei biofilm. The enzymatic systems of single and mixed biofilms were evaluated regarding their efficiency on cellulosic substrates degradation. Washed solids from steam pretreated beechwood, as well as microcrystalline cellulose were used as the substrates. The enzymatic system of the multispecies biofilm released four times more glucose than the enzymatic system of T. reesei alone from both substrates and hydrolyzed 78 and 60% of the cellulose content of washed solids from beechwood and microcrystalline cellulose, respectively.}, } @article {pmid29065453, year = {2017}, author = {Passos da Silva, D and Schofield, MC and Parsek, MR and Tseng, BS}, title = {An Update on the Sociomicrobiology of Quorum Sensing in Gram-Negative Biofilm Development.}, journal = {Pathogens (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {29065453}, issn = {2076-0817}, support = {K22 AI121097/AI/NIAID NIH HHS/United States ; P30 DK089507/DK/NIDDK NIH HHS/United States ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; }, abstract = {Bacteria are social creatures that are able to interact and coordinate behaviors with each other in a multitude of ways. The study of such group behaviors in microbes was coined "sociomicrobiology" in 2005. Two such group behaviors in bacteria are quorum sensing (QS) and biofilm formation. At a very basic level, QS is the ability to sense bacterial density via cell-to-cell signaling using self-produced signals called autoinducers, and biofilms are aggregates of cells that are attached to one another via a self-produced, extracellular matrix. Since cells in biofilm aggregates are in close proximity, biofilms represent an ecologically relevant environment for QS. While QS is known to affect biofilm formation in both Gram-negative and Gram-positive species, in this review, we will focus exclusively on Gram-negative bacteria, with an emphasis on Pseudomonas aeruginosa. We will begin by describing QS systems in P. aeruginosa and how they affect P. aeruginosa biofilm formation. We then expand our review to other Gram-negative bacteria and conclude with interesting questions with regard to the effect of biofilms on QS.}, } @article {pmid29064403, year = {2017}, author = {Peng, X and Ekanayaka, SA and McClellan, SA and Barrett, RP and Vistisen, K and Hazlett, LD}, title = {Characterization of Three Ocular Clinical Isolates of P. aeruginosa: Viability, Biofilm Formation, Adherence, Infectivity, and Effects of Glycyrrhizin.}, journal = {Pathogens (Basel, Switzerland)}, volume = {6}, number = {4}, pages = {}, pmid = {29064403}, issn = {2076-0817}, support = {P30 EY004068/EY/NEI NIH HHS/United States ; R01 EY016058/EY/NEI NIH HHS/United States ; }, abstract = {We selectively characterized three isolates from Pseudomonas aeruginosa keratitis patients and how glycyrrhizin (GLY) affected them. Type III toxins were determined using polymerase chain reaction (PCR). Minimum Inhibitory Concentration (MIC) of GLY and assays for its effects on: time kill, bacterial permeability, and biofilm/adhesion were done. In vivo, C57BL/6 (B6) mice were treated topically with GLY after G81007 infection. Clinical score, photography with a slit lamp and RT-PCR were used to assess treatment effects. Isolates expressed exoS and exoT, but not exoU. MIC for all isolates was 40 mg/mL GLY and bacteriostatic effects were seen for G81007 after treatment using time kill assays. From viability testing, GLY treatment significantly increased the number of permeabilized bacteria (live/dead assay). Isolates 070490 and G81007 formed more biofilms compared with R59733 and PAO1 (control). GLY-treated bacteria had diminished biofilm compared with controls for all isolates. GLY reduced adherence of the G81007 isolate to cultured cells and affected specific biofilm associated systems tested by reverse transcription PCR (RT-PCR). In vivo, after G81007 infection, GLY treatment reduced clinical score and messenger RNA (mRNA) expression of IL-1β, TNF-α, CXCL2 and HMGB1. This study provides evidence that GLY is bacteriostatic for G81007. It also affects biofilm production, adherence to cultured cells, and an improved keratitis outcome.}, } @article {pmid29063401, year = {2018}, author = {Al-Ali, A and Deravel, J and Krier, F and Béchet, M and Ongena, M and Jacques, P}, title = {Biofilm formation is determinant in tomato rhizosphere colonization by Bacillus velezensis FZB42.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {30}, pages = {29910-29920}, pmid = {29063401}, issn = {1614-7499}, mesh = {Bacillus/genetics/growth & development/*physiology ; *Biofilms ; Solanum lycopersicum/growth & development/*microbiology ; Plant Roots/microbiology ; Rhizosphere ; *Soil Microbiology ; }, abstract = {In this work, the behavior in tomato rhizosphere of Bacillus velezensis FZB42 was analyzed taking into account the surfactin production, the use of tomato roots exudate as substrates, and the biofilm formation. B. velezensis FZB42 and B. amyloliquefaciens S499 have a similar capability to colonize tomato rhizosphere. Little difference in this colonization was observed with surfactin non producing B. velezensis FZB42 mutant strains. B. velezensis is able to grow in the presence of root exudate and used preferentially sucrose, maltose, glutamic, and malic acids as carbon sources. A mutant enable to produce exopolysaccharide (EPS[-]) was constructed to demonstrate the main importance of biofilm formation on rhizosphere colonization. This mutant had completely lost its ability to form biofilm whatever the substrate present in the culture medium and was unable to efficiently colonize tomato rhizosphere.}, } @article {pmid29062489, year = {2017}, author = {Beaudoin, T and Yau, YCW and Stapleton, PJ and Gong, Y and Wang, PW and Guttman, DS and Waters, V}, title = {Staphylococcus aureus interaction with Pseudomonas aeruginosa biofilm enhances tobramycin resistance.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {25}, pmid = {29062489}, issn = {2055-5008}, abstract = {Antimicrobial resistance is a significant threat to the treatment of infectious disease. Multiple mechanisms of resistance to different classes of antibiotics have been identified and well-studied. However, these mechanisms are studied with bacteria in isolation, whereas often, infections have a polymicrobial basis. Using a biofilm slide chamber model, we visualized the formation and development of clinical Pseudomonas aeruginosa biofilms in the presence of secreted Staphylococcus aureus exoproducts, two bacteria that commonly co-infect pediatric patients with cystic fibrosis. We showed that, over time, certain isolates of P. aeruginosa can form different biofilm architecture in the presence of S. aureus exoproducts. We further determined that this interaction was dependent on Psl produced by P. aeruginosa and staphylococcal protein A from S. aureus. Importantly, we identified a mechanism of antibiotic resistance to tobramycin that is dependent on the polymicrobial interactions between these two bacteria. This interaction occurred in isolates of P. aeruginosa recovered from children with cystic fibrosis who failed to clear P. aeruginosa following inhaled tobramycin treatment.}, } @article {pmid29061740, year = {2018}, author = {Yu, W and Hallinen, KM and Wood, KB}, title = {Interplay between Antibiotic Efficacy and Drug-Induced Lysis Underlies Enhanced Biofilm Formation at Subinhibitory Drug Concentrations.}, journal = {Antimicrobial agents and chemotherapy}, volume = {62}, number = {1}, pages = {}, pmid = {29061740}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Wall/drug effects ; Drug Resistance, Bacterial/*genetics ; Enterococcus faecalis/*drug effects/genetics ; Gram-Positive Bacterial Infections/*drug therapy/microbiology ; Humans ; Microbial Sensitivity Tests ; Models, Theoretical ; Surface-Active Agents/*pharmacology ; }, abstract = {Subinhibitory concentrations of antibiotics have been shown to enhance biofilm formation in multiple bacterial species. While antibiotic exposure has been associated with modulated expression of many biofilm-related genes, the mechanisms of drug-induced biofilm formation remain a focus of ongoing research efforts and may vary significantly across species. In this work, we investigate antibiotic-induced biofilm formation in Enterococcus faecalis, a leading cause of nosocomial infections. We show that biofilm formation is enhanced by subinhibitory concentrations of cell wall synthesis inhibitors but not by inhibitors of protein, DNA, folic acid, or RNA synthesis. Furthermore, enhanced biofilm is associated with increased cell lysis, increases in extracellular DNA (eDNA) levels, and increases in the density of living cells in the biofilm. In addition, we observe similar enhancement of biofilm formation when cells are treated with nonantibiotic surfactants that induce cell lysis. These findings suggest that antibiotic-induced biofilm formation is governed by a trade-off between drug toxicity and the beneficial effects of cell lysis. To understand this trade-off, we developed a simple mathematical model that predicts changes in antibiotic-induced biofilm formation due to external perturbations, and we verified these predictions experimentally. Specifically, we demonstrate that perturbations that reduce eDNA (DNase treatment) or decrease the number of living cells in the planktonic phase (a second antibiotic) decrease biofilm induction, while chemical inhibitors of cell lysis increase relative biofilm induction and shift the peak to higher antibiotic concentrations. Overall, our results offer experimental evidence linking cell wall synthesis inhibitors, cell lysis, increased eDNA levels, and biofilm formation in E. faecalis while also providing a predictive quantitative model that sheds light on the interplay between cell lysis and antibiotic efficacy in developing biofilms.}, } @article {pmid29058654, year = {2017}, author = {Eder, AE and Munir, SA and Hobby, CR and Anderson, DM and Herndon, JL and Siv, AW and Symes, SJK and Giles, DK}, title = {Exogenous polyunsaturated fatty acids (PUFAs) alter phospholipid composition, membrane permeability, biofilm formation and motility in Acinetobacter baumannii.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {11}, pages = {1626-1636}, doi = {10.1099/mic.0.000556}, pmid = {29058654}, issn = {1465-2080}, mesh = {Acinetobacter baumannii/chemistry/drug effects/*physiology ; Adaptation, Physiological ; Anti-Bacterial Agents/pharmacology ; Bacterial Translocation/*physiology ; Biofilms/*growth & development ; Cell Membrane Permeability/*physiology ; Chromatography, High Pressure Liquid ; Chromatography, Thin Layer ; Colistin/pharmacology ; Drug Resistance, Bacterial/*physiology ; Fatty Acids, Unsaturated/*metabolism ; Microbial Sensitivity Tests ; Phospholipids/analysis/classification/*metabolism ; Polymyxin B/pharmacology ; Tandem Mass Spectrometry ; }, abstract = {Acinetobacter baumannii is a ubiquitous multidrug-resistant bacteria that is found on a variety of surfaces, including skin, hair and soil. During the past decade, A. baumannii has emerged as a significant cause of nosocomial infections in the United States. Recent studies have highlighted the ability of some bacteria to utilize a wide variety of fatty acids as a membrane remodelling strategy. Considering this, we hypothesized that fatty acids may have an effect on the emerging pathogen A. baumannii. Thin-layer chromatography indicated structural alterations to major phospholipids. Liquid chromatography/mass spectrometry confirmed the assimilation of numerous exogenous polyunsaturated fatty acids (PUFAs) into the phospholipid species of A. baumannii. The incorporation of fatty acids affected several bacterial phenotypes, including membrane permeability, biofilm formation, surface motility and antimicrobial peptide resistance.}, } @article {pmid29058454, year = {2018}, author = {Pande, V and McWhorter, AR and Chousalkar, KK}, title = {Anti-bacterial and anti-biofilm activity of commercial organic acid products against Salmonella enterica isolates recovered from an egg farm environment.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {47}, number = {2}, pages = {189-196}, doi = {10.1080/03079457.2017.1394979}, pmid = {29058454}, issn = {1465-3338}, mesh = {Animals ; Biofilms/*drug effects ; *Chickens ; Disinfectants/chemistry/*pharmacology ; Farms ; Poultry Diseases/*microbiology ; Salmonella Infections, Animal/*microbiology ; Salmonella enterica/*drug effects/isolation & purification ; }, abstract = {This study evaluated the antibacterial activity of commercially available organic acid water additives against Salmonella enterica isolates and examined the susceptibility of Salmonella Typhimurium biofilms to these products. Three commercial organic acid products (A, B, and C) were evaluated for minimum inhibitory and bactericidal concentrations against isolates of S. enterica serovars. Three- and five-day-old S. Typhimurium biofilms were formed at 22 ± 2°C using an MBEC™ assay system and exposed for 30 min or 90 min at 0.2% and 0.4% concentrations. No significant difference among serovars for inhibitory and bactericidal concentrations was detected. Two products (A and C) significantly reduced viable cells from biofilms of both ages in a dose- and time-dependent manner. Increased biofilm age did not enhance resistance towards organic acid treatments. None of the products completely eliminated biofilm cells at any concentration or exposure time. Product composition, exposure time, and concentration of organic acid products were important factors in reducing viable biofilm cells. This study has expanded our understanding about the susceptibility of Salmonella biofilms to commercial organic acid products. These findings have implications in the usage, development, and optimization of organic acid products.}, } @article {pmid29057263, year = {2017}, author = {Gupta, TT and Karki, SB and Matson, JS and Gehling, DJ and Ayan, H}, title = {Sterilization of Biofilm on a Titanium Surface Using a Combination of Nonthermal Plasma and Chlorhexidine Digluconate.}, journal = {BioMed research international}, volume = {2017}, number = {}, pages = {6085741}, pmid = {29057263}, issn = {2314-6141}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/drug effects/radiation effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Humans ; Microbial Viability/drug effects/radiation effects ; *Plasma Gases ; Pseudomonas aeruginosa/drug effects/pathogenicity ; Sterilization/*methods ; Titanium/chemistry ; }, abstract = {Nosocomial infections caused by opportunistic bacteria pose major healthcare problem worldwide. Out of the many microorganisms responsible for such infections, Pseudomonas aeruginosa is a ubiquitous bacterium that accounts for 10-20% of hospital-acquired infections. These infections have mortality rates ranging from 18 to 60% and the cost of treatment ranges from $20,000 to $80,000 per infection. The formation of biofilms on medical devices and implants is responsible for the majority of those infections. Only limited progress has been made to prevent this issue in a safe and cost-effective manner. To address this, we propose employing jet plasma to break down and inactivate biofilms in vitro. Moreover, to improve the antimicrobial effect on the biofilm, a treatment method using a combination of jet plasma and a biocide known as chlorhexidine (CHX) digluconate was investigated. We found that complete sterilization of P. aeruginosa biofilms can be achieved after combinatorial treatment using plasma and CHX. A decrease in biofilm viability was also observed using confocal laser scanning electron microscopy (CLSM). This treatment method sterilized biofilm-contaminated surfaces in a short treatment time, indicating it to be a potential tool for the removal of biofilms present on medical devices and implants.}, } @article {pmid29056457, year = {2017}, author = {Singh, PK and Bartalomej, S and Hartmann, R and Jeckel, H and Vidakovic, L and Nadell, CD and Drescher, K}, title = {Vibrio cholerae Combines Individual and Collective Sensing to Trigger Biofilm Dispersal.}, journal = {Current biology : CB}, volume = {27}, number = {21}, pages = {3359-3366.e7}, pmid = {29056457}, issn = {1879-0445}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Biological Transport/physiology ; Gene Expression Regulation, Bacterial ; Quorum Sensing/*physiology ; Sigma Factor/metabolism ; Starvation/*metabolism ; Vibrio cholerae/*growth & development/physiology ; }, abstract = {Bacteria can generate benefits for themselves and their kin by living in multicellular, matrix-enclosed communities, termed biofilms, which are fundamental to microbial ecology and the impact bacteria have on the environment, infections, and industry [1-6]. The advantages of the biofilm mode of life include increased stress resistance and access to concentrated nutrient sources [3, 7, 8]. However, there are also costs associated with biofilm growth, including the metabolic burden of biofilm matrix production, increased resource competition, and limited mobility inside the community [9-11]. The decision-making strategies used by bacteria to weigh the costs between remaining in a biofilm or actively dispersing are largely unclear, even though the dispersal transition is a central aspect of the biofilm life cycle and critical for infection transmission [12-14]. Using a combination of genetic and novel single-cell imaging approaches, we show that Vibrio cholerae integrates dual sensory inputs to control the dispersal response: cells use the general stress response, which can be induced via starvation, and they also integrate information about the local cell density and molecular transport conditions in the environment via the quorum sensing apparatus. By combining information from individual (stress response) and collective (quorum sensing) avenues of sensory input, biofilm-dwelling bacteria can make robust decisions to disperse from large biofilms under distress, while preventing premature dispersal when biofilm populations are small. These insights into triggers and regulators of biofilm dispersal are a key step toward actively inducing biofilm dispersal for technological and medical applications, and for environmental control of biofilms.}, } @article {pmid29056184, year = {2017}, author = {Zero, DT}, title = {Evidence for biofilm acid neutralization by baking soda.}, journal = {Journal of the American Dental Association (1939)}, volume = {148}, number = {11S}, pages = {S10-S14}, doi = {10.1016/j.adaj.2017.09.005}, pmid = {29056184}, issn = {1943-4723}, mesh = {Biofilms/*drug effects ; Humans ; Hydrogen-Ion Concentration ; Saliva/metabolism ; Sodium Bicarbonate/*pharmacology ; }, abstract = {BACKGROUND: The generating of acids from the microbial metabolism of dietary sugars and the subsequent decrease in biofilm pH below the pH at which tooth mineral begins to demineralize (critical pH) are the key elements of the dental caries process. Caries preventive strategies that rapidly neutralize biofilm acids can prevent demineralization and favor remineralization and may help prevent the development of sugar-induced dysbiosis that shifts the biofilm toward increased cariogenic potential. Although the neutralizing ability of sodium bicarbonate (baking soda) has been known for many years, its anticaries potential as an additive to fluoride dentifrice has received only limited investigation.

TYPES OF STUDIES REVIEWED: There is evidence that baking soda rapidly can reverse the biofilm pH decrease after a sugar challenge; however, the timing of when it is used in relation to a dietary sugar exposure is critical in that the sooner its used the greater the benefit in preventing a sustained biofilm pH decrease and subsequent demineralization. Furthermore, the effectiveness of baking soda in elevating biofilm pH appears to depend on concentration. Thus, the concentration of baking soda in marketed dentifrice products, which ranges from 10% to 65%, may affect their biofilm pH neutralizing performance. People with hyposalivation particularly may benefit from using fluoride dentifrice containing baking soda because of their diminished ability to clear dietary sugars and buffer biofilm acids.

CONCLUSIONS: Although promising, there is the need for more evidence that strategies that modify the oral ecology, such as baking soda, can alter the cariogenic (acidogenic and aciduric) properties of biofilm microorganisms.

PRACTICAL IMPLICATIONS: The acid neutralization of dental biofilm by using fluoride dentifrice that contains baking soda has potential for helping counteract modern high-sugar diets by rapidly neutralizing biofilm-generated acid, especially in people with hyposalivation.}, } @article {pmid29055828, year = {2017}, author = {Dhar, BR and Sim, J and Ryu, H and Ren, H and Santo Domingo, JW and Chae, J and Lee, HS}, title = {Microbial activity influences electrical conductivity of biofilm anode.}, journal = {Water research}, volume = {127}, number = {}, pages = {230-238}, pmid = {29055828}, issn = {1879-2448}, support = {EPA999999/ImEPA/Intramural EPA/United States ; }, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Buffers ; Electric Conductivity ; *Electrodes ; Geobacter/chemistry ; Gold ; Hydrogen-Ion Concentration ; Microscopy, Confocal ; Phosphates/chemistry ; Protons ; }, abstract = {This study assessed the conductivity of a Geobacter-enriched biofilm anode in a microbial electrochemical cell (MxC) equipped with two gold anodes (25 mM acetate medium), as different proton gradients were built throughout the biofilm. There was no pH gradient across the biofilm anode at 100 mM phosphate buffer (current density 2.38 A/m[2]) and biofilm conductivity (Kbio) was as high as 0.87 mS/cm. In comparison, an inner biofilm became acidic at 2.5 mM phosphate buffer in which dead cells were accumulated at ∼80 μm of the inner biofilm anode. At this low phosphate buffer, Kbio significantly decreased by 0.27 mS/cm, together with declined current density of 0.64 A/m[2]. This work demonstrates that biofilm conductivity depends on the composition of live and dead cells in the conductive biofilm anode.}, } @article {pmid29053700, year = {2017}, author = {Hunt, AMA and Gibson, JA and Larrivee, CL and O'Reilly, S and Navitskaya, S and Busik, JV and Waters, CM}, title = {Come to the Light Side: In Vivo Monitoring of Pseudomonas aeruginosa Biofilm Infections in Chronic Wounds in a Diabetic Hairless Murine Model.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {128}, pages = {}, pmid = {29053700}, issn = {1940-087X}, mesh = {Animals ; Biofilms/*drug effects ; Diabetes Mellitus, Experimental ; Disease Models, Animal ; Humans ; Mice ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects ; Wound Healing/drug effects ; Wound Infection/*etiology ; }, abstract = {The presence of bacteria as structured biofilms in chronic wounds, especially in diabetic patients, is thought to prevent wound healing and resolution. Chronic mouse wounds models have been used to understand the underlying interactions between the microorganisms and the host. The models developed to date rely on the use of haired animals and terminal collection of wound tissue for determination of viable bacteria. While significant insight has been gained with these models, this experimental procedure requires a large number of animals and sampling is time consuming. We have developed a novel murine model that incorporates several optimal innovations to evaluate biofilm progression in chronic wounds: a) it utilizes hairless mice, eliminating the need for hair removal; b) applies pre-formed biofilms to the wounds allowing for the immediate evaluation of persistence and effect of these communities on host; c) monitors biofilm progression by quantifying light production by a genetically engineered bioluminescent strain of Pseudomonas aeruginosa, allowing real-time monitoring of the infection thus reducing the number of animals required per study. In this model, a single full-depth wound is produced on the back of STZ-induced diabetic hairless mice and inoculated with biofilms of the P. aeruginosa bioluminescent strain Xen 41. Light output from the wounds is recorded daily in an in vivo imaging system, allowing for in vivo and in situ rapid biofilm visualization and localization of biofilm bacteria within the wounds. This novel method is flexible as it can be used to study other microorganisms, including genetically engineered species and multi-species biofilms, and may be of special value in testing anti-biofilm strategies including antimicrobial occlusive dressings.}, } @article {pmid29053421, year = {2017}, author = {Jose, D and Lekshmi, N and Goel, AK and Kumar, RA and Thomas, S}, title = {Development of a Novel Herbal Formulation To Inhibit Biofilm Formation in Toxigenic Vibrio cholerae.}, journal = {Journal of food protection}, volume = {80}, number = {11}, pages = {1933-1940}, doi = {10.4315/0362-028X.JFP-17-091}, pmid = {29053421}, issn = {1944-9097}, abstract = {Vibrio cholerae, a causative agent of the waterborne disease cholera, still threatens a large proportion of world's population. The role of biofilm formation in V. cholerae pathogenesis is well established, as it provides the bacterium enhanced tolerance to antimicrobial agents and increased transmission. In the present study, four medicinal plants used in traditional medicines with antidiarrheal properties were evaluated for its antibiofilm activity. Methanol extracts of these plants (Centella asiatica, Elephantopus scaber, Camellia sinensis, and Holarrhena antidysenterica) showed promising antibiofilm activity against V. cholerae with crystal violet and air-liquid interface coverslip assays. Results revealed that C. asiatica, E. scaber, C. sinensis, and H. antidysenterica extracts significantly inhibited biofilm formation by approximately 75, 76, 78, and 55% at concentrations of 3, 2, 1, and 0.6 mg/mL, respectively. A promising antibiofilm activity of ∼89% inhibition at 1.5 mg/mL concentration was observed when a combination of E. scaber and C. sinensis was used. The herbal extracts were thermostable at a temperature range of 40 to 100°C. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that the viability of bacteria was not affected by treatment with these plant extracts. Gene expression studies revealed that extracts of H. antidysenterica leaf, H. antidysenterica bark, and the whole plant of E. scaber and C. asiatica down-regulate aphA or aphB, the major regulator genes modulating both virulence and biofilm formation. Hence, we propose that these herbal combinations could serve as a multifaceted approach to combat the pathogen and also, in turn, reduce antimicrobial resistance development.}, } @article {pmid29053370, year = {2018}, author = {Dantas, STA and Rossi, BF and Bonsaglia, ECR and Castilho, IG and Hernandes, RT and Fernandes, A and Rall, VLM}, title = {Cross-Contamination and Biofilm Formation by Salmonella enterica Serovar Enteritidis on Various Cutting Boards.}, journal = {Foodborne pathogens and disease}, volume = {15}, number = {2}, pages = {81-85}, doi = {10.1089/fpd.2017.2341}, pmid = {29053370}, issn = {1556-7125}, mesh = {Animals ; *Biofilms ; *Food Contamination ; Food Handling ; Food Microbiology ; Foodborne Diseases/microbiology ; Genes, Bacterial ; Microscopy, Electron, Scanning ; Poultry/microbiology ; Salmonella enteritidis/*isolation & purification ; }, abstract = {Cross-contamination is one of the main factors related to foodborne outbreaks. This study aimed to analyze the cross-contamination process of Salmonella enterica serovar Enteritidis from poultry to cucumbers, on various cutting board surfaces (plastic, wood, and glass) before and after washing and in the presence and absence of biofilm. Thus, 10 strains of Salmonella Enteritidis were used to test cross-contamination from poultry to the cutting boards and from thereon to cucumbers. Moreover, these strains were evaluated as to their capacity to form biofilm on hydrophobic (wood and plastic) and hydrophilic materials (glass). We recovered the 10 isolates from all unwashed boards and from all cucumbers that had contacted them. After washing, the recovery ranged from 10% to 100%, depending on the board material. In the presence of biofilm, the recovery of salmonellae was 100%, even after washing. Biofilm formation occurred more on wood (60%) and plastic (40%) than glass (10%) boards, demonstrating that bacteria adhered more to a hydrophobic material. It was concluded that the cutting boards represent a critical point in cross-contamination, particularly in the presence of biofilm. Salmonella Enteritidis was able to form a biofilm on these three types of cutting boards but glass showed the least formation.}, } @article {pmid29053252, year = {2018}, author = {Pu, L and Yang, S and Xia, A and Jin, F}, title = {Optogenetics Manipulation Enables Prevention of Biofilm Formation of Engineered Pseudomonas aeruginosa on Surfaces.}, journal = {ACS synthetic biology}, volume = {7}, number = {1}, pages = {200-208}, doi = {10.1021/acssynbio.7b00273}, pmid = {29053252}, issn = {2161-5063}, mesh = {Bacterial Proteins/genetics ; *Biofilms/radiation effects ; Cyclic GMP/analogs & derivatives/metabolism ; Green Fluorescent Proteins/genetics/metabolism ; Histidine Kinase/genetics ; Light ; Microscopy, Fluorescence ; Optogenetics/*methods ; Plasmids/genetics/metabolism ; Pseudomonas aeruginosa/*physiology ; Time-Lapse Imaging ; }, abstract = {Synthetic biologists have attempted to solve real-world problems, such as those of bacterial biofilms, that are involved in the pathogenesis of many clinical infections and difficult to eliminate. To address this, we employed a blue light responding system and integrated it into the chromosomes of Pseudomonas aeruginosa. With making rational adaptions and improvements of the light-activated system, we provided a robust and convenient means to spatiotemporally control gene expression and manipulate biological processes with minimal perturbation in P. aeruginosa. It increased the light-induced gene expression up to 20-fold. Moreover, we deliberately introduced a functional protein gene PA2133 containing an EAL domain to degrade c-di-GMP into the modified system, and showed that the optimally engineered optogenetic tool inhibited the formation of P. aeruginosa biofilms through the induction of blue light, resulting in much sparser and thinner biofilms. Our approach establishes a methodology for leveraging the tools of synthetic biology to guide biofilm formation and engineer biofilm patterns with unprecedented spatiotemporal resolution. Furthermore, the findings suggest that the synthetic optogenetic system may provide a promising strategy that could be applied to control and fight biofilms.}, } @article {pmid29052931, year = {2018}, author = {Hernández-Prieto, MA and Li, Y and Postier, BL and Blankenship, RE and Chen, M}, title = {Far-red light promotes biofilm formation in the cyanobacterium Acaryochloris marina.}, journal = {Environmental microbiology}, volume = {20}, number = {2}, pages = {535-545}, doi = {10.1111/1462-2920.13961}, pmid = {29052931}, issn = {1462-2920}, mesh = {Biofilms/*radiation effects ; Chlorophyll/biosynthesis ; Cyanobacteria/genetics/metabolism/*physiology/radiation effects ; Ecosystem ; *Light ; Photosynthesis/genetics ; Transcriptome/radiation effects ; }, abstract = {Light quantity and quality promotes ecological-niche differentiation of photosynthetic organisms. The existence of cyanobacteria capable of performing photosynthesis using red-shifted chlorophylls, chlorophyll d and f, reduces competition between species in light-limiting environments, and permits them to thrive in niches enriched in far-red light. We examined global transcriptome changes due to changing the culture light conditions in Acaryochloris marina, a chlorophyll d-containing cyanobacterium. We identified the functional category of 'photosynthesis' as the most down-regulated and the category of 'cell wall/membrane biogenesis' as the most up-regulated through a functional enrichment analysis of genes differentially expressed. Within the category of 'cell wall/membrane biogenesis', genes encoding glycosysltransferases accumulated the most in response to far-red light. Further experimental results confirmed that cells grown under far-red light form biofilms with a significantly increased adherence compared to cells grown under white light. Taken together, these results indicate that Acaryochloris marina shifts its lifestyle from a planktonic state under white light to an immobilized state under far-red light.}, } @article {pmid29051259, year = {2017}, author = {Wan, X and Darris, M and Hou, S and Donachie, SP}, title = {Draft Genome Sequence of a Novel Chitinophaga sp. Strain, MD30, Isolated from a Biofilm in an Air Conditioner Condensate Pipe.}, journal = {Genome announcements}, volume = {5}, number = {42}, pages = {}, pmid = {29051259}, issn = {2169-8287}, abstract = {Most of the 24 known Chitinophaga species were originally isolated from soils. We report the draft genome sequence of a putatively novel Chitinophaga sp. from a biofilm in an air conditioner condensate pipe. The genome comprises 7,661,303 bp in one scaffold, 5,694 predicted protein-coding sequences, and a G+C content of 47.6%.}, } @article {pmid29050256, year = {2017}, author = {Zeng, B and Li, J and Wang, Y and Chen, P and Wang, X and Cui, J and Liu, L and Hu, X and Cao, Q and Xiao, Y and Dong, J and Sun, Y and Zhou, Y}, title = {In vitro and in vivo effects of suloctidil on growth and biofilm formation of the opportunistic fungus Candida albicans.}, journal = {Oncotarget}, volume = {8}, number = {41}, pages = {69972-69982}, pmid = {29050256}, issn = {1949-2553}, abstract = {As the most frequent fungal pathogen in humans, Candida albicans can develop serious drug resistance because its biofilms are resistant to most antifungal agents; this leads to an urgent need to develop novel antifungals. Here, we evaluated the efficacy of an antithrombotic drug, suloctidil, against C. albicans biofilms in vitro and in vivo. We found that suloctidil is effective to inhibit C. albicans biofilm, with a minimum inhibitory concentration (MIC80) of 4 μg/mL, a biofilm inhibiting concentration (BIC80) of 16 μg/mL and a biofilm eradicating concentration (BEC80) of 64 μg/mL. Furthermore, the concentration-dependent characteristics of suloctidil were shown by its time-kill curves. Scanning electron microscopy images clearly revealed the morphological effects of suloctidil on biofilm. Yeast-to-hyphal form switching is a key virulence factor of C. albicans; therefore, we performed hyphal growth tests and observed that suloctidil inhibited yeast-to-hyphal form switching. This result was consistent with the down-regulation of hypha-specific gene (HWP1, ALS3, and ECE1) expression levels after suloctidil treatment. In vivo, 256 μg/mL of suloctidil significantly reduced fungal counts (P<0.01) compared to that in groups without treatment; the treatment group induced a slight histological reaction, especially when the treatment lasted for 5 days (P<0.01). Taken together, our data suggest that suloctidil is a potential antifungal agent.}, } @article {pmid29050024, year = {2017}, author = {Maltz, M and Alves, LS and Zenkner, JEDA}, title = {Biofilm Control and Oral Hygiene Practices.}, journal = {Monographs in oral science}, volume = {26}, number = {}, pages = {76-82}, doi = {10.1159/000479348}, pmid = {29050024}, issn = {0077-0892}, mesh = {Biofilms ; *Dental Caries ; Humans ; *Oral Hygiene ; }, abstract = {As the thick biofilm in the presence of fermentable carbohydrates is the main etiological factor of dental caries, the frequent and systematic removal of this colony by means of an effective biofilm control should result in the prevention of caries lesions or in the arrest of the local carious process. However, the role of biofilm control in the management of dental caries has been questioned. This chapter will discuss the biofilm control and oral hygiene practices on root surfaces. Laboratory and clinical studies describing the effect of biofilm control and oral hygiene practices on the arrestment of root carious lesions are described. Epidemiological surveys evaluating the association between oral hygiene and root caries are discussed. Finally, some aspects on chemical biofilm control are also presented.}, } @article {pmid29049982, year = {2018}, author = {Li, J and Wei, J and Ngo, HH and Guo, W and Liu, H and Du, B and Wei, Q and Wei, D}, title = {Characterization of soluble microbial products in a partial nitrification sequencing batch biofilm reactor treating high ammonia nitrogen wastewater.}, journal = {Bioresource technology}, volume = {249}, number = {}, pages = {241-246}, doi = {10.1016/j.biortech.2017.10.013}, pmid = {29049982}, issn = {1873-2976}, mesh = {Ammonia ; Biofilms ; Bioreactors ; *Nitrification ; Nitrogen ; *Wastewater ; }, abstract = {In present study, the characterization of soluble microbial products (SMP) was evaluated in a partial nitrification sequencing batch biofilm reactor (SBBR). During the stable operation of SBBR, the NH4[+]-N removal efficiency and nitrite accumulation ratio were 96.70±0.41% and 93.77±1.04%, respectively. According to excitation-emission matrix (EEM), the intensities of protein-like substances were reduced under anoxic and aerobic phases, whereas humic-like substances had little change during the whole cycle. Parallel factor analysis (PARAFAC) further indentified two components and their fluorescence intensity scores were both reduced. Synchronous fluorescence spectra revealed that the fluorescence intensity of protein-like fraction decreased with reaction time. Two-dimensional correlation spectroscopy (2D-COS) further demonstrated that protein-like fraction might decrease earlier than the other fractions. The information obtained in present study is of fundamental significance for understanding the key components in SMP and their changes in partial nitrification system by using a spectral approach.}, } @article {pmid29049010, year = {2017}, author = {Lim, SY and Teh, CSJ and Thong, KL}, title = {Biofilm-Related Diseases and Omics: Global Transcriptional Profiling of Enterococcus faecium Reveals Different Gene Expression Patterns in the Biofilm and Planktonic Cells.}, journal = {Omics : a journal of integrative biology}, volume = {21}, number = {10}, pages = {592-602}, doi = {10.1089/omi.2017.0119}, pmid = {29049010}, issn = {1557-8100}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Enterococcus faecium/*genetics ; Gene Expression Profiling/methods ; Gene Expression Regulation, Bacterial/*genetics ; Plankton/*genetics ; Transcription, Genetic/*genetics ; Transcriptome/*genetics ; Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {Enterococcus faecium is an opportunistic pathogen with a remarkable ability to acquire resistance toward multiple antibiotics, including those of last-resort drugs such as vancomycin and daptomycin. The occurrence of vancomycin-resistant E. faecium is on the rise and there is a need to understand the virulence of this organism. One of the factors that contributes to the virulence is the ability to form biofilms. Since bacteria in biofilm state are more resistant to antibiotics and host immune response, understanding the molecular mechanism of biofilm development is important to control biofilm-related diseases. The aim of this study was to determine the global gene expression profiles of an E. faecium strain, VREr5, during the early event of sessile growth compared with its planktonic phase through RNA-sequencing approach. The results clearly illustrated distinct expression profiles of the planktonic and biofilm cells. A total of 177 genes were overexpressed in the biofilm cells. Most of them encode for proteins involved in adherence, such as the ebpABCfm locus. Genes associated with plasmid replication, gene exchange, and protein synthesis were also upregulated during the early event of biofilm development. Furthermore, the transcriptome analysis also identified genes such as fsrB, luxS, and spx that might suppress biofilm formation in VREr5. The putative biofilm-related bee locus was found to be downregulated. These new findings could provide caveats for future studies on the regulation and maintenance of biofilm and development of biomarkers for biofilm-related diseases.}, } @article {pmid29047302, year = {2017}, author = {Mandal, SM and Khan, J and Mahata, D and Saha, S and Sengupta, J and Silva, ON and Das, S and Mandal, M and Franco, OL}, title = {A self-assembled clavanin A-coated amniotic membrane scaffold for the prevention of biofilm formation by ocular surface fungal pathogens.}, journal = {Biofouling}, volume = {33}, number = {10}, pages = {881-891}, doi = {10.1080/08927014.2017.1383400}, pmid = {29047302}, issn = {1029-2454}, mesh = {Alternaria/drug effects/physiology ; Amnion/*microbiology/transplantation ; Anti-Bacterial Agents ; Antifungal Agents/*pharmacology ; Aspergillus fumigatus/drug effects/physiology ; Biofilms/*drug effects ; Blood Proteins/*pharmacology ; Candida albicans/drug effects ; Fusarium/drug effects/physiology ; HEK293 Cells ; Humans ; }, abstract = {Amniotic membrane (AM) is frequently used in ophthalmologic surgery for rapid ocular surface reconstruction. Sometimes it may create a major problem with associated infections after biofilm formation over the membrane. To overcome this problem, AM was coated with the antimicrobial peptide clavanin A. The antifungal activity of clavanin A in the native and self-assembled form was determined against the common ocular surface pathogens Candida albicans, Aspergillus fumigatus, Alternaria sp. and Fusarium sp. Biofilm formation over the coated surface was significantly reduced in comparison with the uncoated membrane. The coated membrane revealed effectiveness in terms of biocompatibility, cell attachment colonization when tested in non-cancerous 3T3 and human embryonic kidney (HEK)-293 cell lines. Clavanin A-coated AM also exhibited excellent physical, morphological and antifungal characteristics, indicating potential applicability for ocular surface infection control.}, } @article {pmid29047237, year = {2017}, author = {Lee, KH and Park, SJ and Choi, SJ and Park, JY}, title = {Proteus vulgaris and Proteus mirabilis Decrease Candida albicans Biofilm Formation by Suppressing Morphological Transition to Its Hyphal Form.}, journal = {Yonsei medical journal}, volume = {58}, number = {6}, pages = {1135-1143}, pmid = {29047237}, issn = {1976-2437}, mesh = {Biofilms/*growth & development ; Candida albicans/genetics/isolation & purification/*physiology ; Gene Expression Regulation, Fungal ; Hyphae/*genetics/growth & development ; Microbial Interactions/genetics ; Proteus mirabilis/*physiology ; Proteus vulgaris/*physiology ; Real-Time Polymerase Chain Reaction ; }, abstract = {PURPOSE: Candida albicans (C. albicans) and Proteus species are causative agents in a variety of opportunistic nosocomial infections, and their ability to form biofilms is known to be a virulence factor. In this study, the influence of co-cultivation with Proteus vulgaris (P. vulgaris) and Proteus mirabilis (P. mirabilis) on C. albicans biofilm formation and its underlying mechanisms were examined.

MATERIALS AND METHODS: XTT reduction assays were adopted to measure biofilm formation, and viable colony counts were performed to quantify yeast growth. Real-time reverse transcriptase polymerase chain reaction was used to evaluate the expression of yeast-specific genes (rhd1 and rbe1), filament formation inhibiting genes (tup1 and nrg1), and hyphae-related genes (als3, ece1, hwp1, and sap5).

RESULTS: Candida biofilm formation was markedly inhibited by treatment with either living or heat-killed P. vulgaris and P. mirabilis. Proteus-cultured supernatant also inhibited Candida biofilm formation. Likewise, treatment with live P. vulgaris or P. mirabilis or with Proteus-cultured supernatant decreased expression of hyphae-related C. albicans genes, while the expression of yeast-specific genes and the filament formation inhibiting genes of C. albicans were increased. Heat-killed P. vulgaris and P. mirabilis treatment, however, did not affect the expression of C. albicans morphology-related genes.

CONCLUSION: These results suggest that secretory products from P. vulgaris and P. mirabilis regulate the expression of genes related to morphologic changes in C. albicans such that transition from the yeast form to the hyphal form can be inhibited.}, } @article {pmid29046665, year = {2017}, author = {Singh, S and Kalia, NP and Joshi, P and Kumar, A and Sharma, PR and Kumar, A and Bharate, SB and Khan, IA}, title = {Boeravinone B, A Novel Dual Inhibitor of NorA Bacterial Efflux Pump of Staphylococcus aureus and Human P-Glycoprotein, Reduces the Biofilm Formation and Intracellular Invasion of Bacteria.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1868}, pmid = {29046665}, issn = {1664-302X}, abstract = {This study elucidated the role of boeravinone B, a NorA multidrug efflux pump inhibitor, in biofilm inhibition. The effects of boeravinone B plus ciprofloxacin, a NorA substrate, were evaluated in NorA-overexpressing, wild-type, and knocked-out Staphylococcus aureus (SA-1199B, SA-1199, and SA-K1758, respectively). The mechanism of action was confirmed using the ethidium bromide accumulation and efflux assay. The role of boeravinone B as a human P-glycoprotein (P-gp) inhibitor was examined in the LS-180 (colon cancer) cell line. Moreover, its role in the inhibition of biofilm formation and intracellular invasion of S. aureus in macrophages was studied. Boeravinone B reduced the minimum inhibitory concentration (MIC) of ciprofloxacin against S. aureus and its methicillin-resistant strains; the effect was stronger in SA-1199B. Furthermore, time-kill kinetics revealed that boeravinone B plus ciprofloxacin, at subinhibitory concentration (0.25 × MIC), is as equipotent as that at the MIC level. This combination also had a reduced mutation prevention concentration. Boeravinone B reduced the efflux of ethidium bromide and increased the accumulation, thus strengthening the role as a NorA inhibitor. Biofilm formation was reduced by four-eightfold of the minimal biofilm inhibitory concentration of ciprofloxacin, effectively preventing bacterial entry into macrophages. Boeravinone B effectively inhibited P-gp with half maximal inhibitory concentration (IC50) of 64.85 μM. The study concluded that boeravinone B not only inhibits the NorA-mediated efflux of fluoroquinolones but also considerably inhibits the biofilm formation of S. aureus. Its P-gp inhibition activity demonstrates its potential as a bioavailability and bioefficacy enhancer.}, } @article {pmid29045455, year = {2017}, author = {Wotanis, CK and Brennan, WP and Angotti, AD and Villa, EA and Zayner, JP and Mozina, AN and Rutkovsky, AC and Sobe, RC and Bond, WG and Karatan, E}, title = {Relative contributions of norspermidine synthesis and signaling pathways to the regulation of Vibrio cholerae biofilm formation.}, journal = {PloS one}, volume = {12}, number = {10}, pages = {e0186291}, pmid = {29045455}, issn = {1932-6203}, support = {R15 AI096358/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Catechols/metabolism ; Cyclic GMP/analogs & derivatives/metabolism ; Iron/metabolism ; Oxazoles/metabolism ; Periplasmic Binding Proteins/genetics/metabolism ; Phosphoric Diester Hydrolases/genetics/metabolism ; Signal Transduction ; Spermidine/*analogs & derivatives/biosynthesis/metabolism ; Vibrio cholerae/*genetics/growth & development/pathogenicity ; }, abstract = {The polyamine norspermidine is one of the major polyamines synthesized by Vibrionales and has also been found in various aquatic organisms. Norspermidine is among the environmental signals that positively regulate Vibrio cholerae biofilm formation. The NspS/MbaA signaling complex detects extracellular norspermidine and mediates the response to this polyamine. Norspermidine binding to the NspS periplasmic binding protein is thought to inhibit the phosphodiesterase activity of MbaA, increasing levels of the biofilm-promoting second messenger cyclic diguanylate monophosphate, thus enhancing biofilm formation. V. cholerae can also synthesize norspermidine using the enzyme NspC as well as import it from the environment. Deletion of the nspC gene was shown to reduce accumulation of bacteria in biofilms, leading to the conclusion that intracellular norspermidine is also a positive regulator of biofilm formation. Because V. cholerae uses norspermidine to synthesize the siderophore vibriobactin it is possible that intracellular norspermidine is required to obtain sufficient amounts of iron, which is also necessary for robust biofilm formation. The objective of this study was to assess the relative contributions of intracellular and extracellular norspermidine to the regulation of biofilm formation in V. cholerae. We show the biofilm defect of norspermidine synthesis mutants does not result from an inability to produce vibriobactin as vibriobactin synthesis mutants do not have diminished biofilm forming abilities. Furthermore, our work shows that extracellular, but not intracellular norspermidine, is mainly responsible for promoting biofilm formation. We establish that the NspS/MbaA signaling complex is the dominant mediator of biofilm formation in response to extracellular norspermidine, rather than norspermidine synthesized by NspC or imported into the cell.}, } @article {pmid29042504, year = {2017}, author = {De León, KB and Zane, GM and Trotter, VV and Krantz, GP and Arkin, AP and Butland, GP and Walian, PJ and Fields, MW and Wall, JD}, title = {Unintended Laboratory-Driven Evolution Reveals Genetic Requirements for Biofilm Formation by Desulfovibrio vulgaris Hildenborough.}, journal = {mBio}, volume = {8}, number = {5}, pages = {}, pmid = {29042504}, issn = {2150-7511}, mesh = {ATP-Binding Cassette Transporters/genetics/*metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; DNA Mutational Analysis ; Desulfovibrio vulgaris/*genetics/*physiology ; *Directed Molecular Evolution ; Genome, Bacterial ; Mutant Proteins/genetics/metabolism ; Point Mutation ; Whole Genome Sequencing ; }, abstract = {Biofilms of sulfate-reducing bacteria (SRB) are of particular interest as members of this group are culprits in corrosion of industrial metal and concrete pipelines as well as being key players in subsurface metal cycling. Yet the mechanism of biofilm formation by these bacteria has not been determined. Here we show that two supposedly identical wild-type cultures of the SRB Desulfovibrio vulgaris Hildenborough maintained in different laboratories have diverged in biofilm formation. From genome resequencing and subsequent mutant analyses, we discovered that a single nucleotide change within DVU1017, the ABC transporter of a type I secretion system (T1SS), was sufficient to eliminate biofilm formation in D. vulgaris Hildenborough. Two T1SS cargo proteins were identified as likely biofilm structural proteins, and the presence of at least one (with either being sufficient) was shown to be required for biofilm formation. Antibodies specific to these biofilm structural proteins confirmed that DVU1017, and thus the T1SS, is essential for localization of these adhesion proteins on the cell surface. We propose that DVU1017 is a member of the lapB category of microbial surface proteins because of its phenotypic similarity to the adhesin export system described for biofilm formation in the environmental pseudomonads. These findings have led to the identification of two functions required for biofilm formation in D. vulgaris Hildenborough and focus attention on the importance of monitoring laboratory-driven evolution, as phenotypes as fundamental as biofilm formation can be altered.IMPORTANCE The growth of bacteria attached to a surface (i.e., biofilm), specifically biofilms of sulfate-reducing bacteria, has a profound impact on the economy of developed nations due to steel and concrete corrosion in industrial pipelines and processing facilities. Furthermore, the presence of sulfate-reducing bacteria in oil wells causes oil souring from sulfide production, resulting in product loss, a health hazard to workers, and ultimately abandonment of wells. Identification of the required genes is a critical step for determining the mechanism of biofilm formation by sulfate reducers. Here, the transporter by which putative biofilm structural proteins are exported from sulfate-reducing Desulfovibrio vulgaris Hildenborough cells was discovered, and a single nucleotide change within the gene coding for this transporter was found to be sufficient to completely stop formation of biofilm.}, } @article {pmid29042302, year = {2017}, author = {Banerjee, M and Moulick, S and Bhattacharya, KK and Parai, D and Chattopadhyay, S and Mukherjee, SK}, title = {Attenuation of Pseudomonas aeruginosa quorum sensing, virulence and biofilm formation by extracts of Andrographis paniculata.}, journal = {Microbial pathogenesis}, volume = {113}, number = {}, pages = {85-93}, doi = {10.1016/j.micpath.2017.10.023}, pmid = {29042302}, issn = {1096-1208}, mesh = {Andrographis/*metabolism ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Cells, Cultured ; Macrophages/immunology ; Mice ; Microbial Sensitivity Tests ; Movement/drug effects ; Plant Extracts/*pharmacology ; Prospective Studies ; Pseudomonas aeruginosa/drug effects/*pathogenicity ; Quorum Sensing/*drug effects ; Virulence Factors/*biosynthesis ; }, abstract = {Quorum-sensing (QS) is known to play an essential role in regulation of virulence factors and toxins during Pseudomonas aeruginosa infection which may frequently cause antibiotic resistance and hostile outcomes of inflammatory injury. Therefore, it is an urgent need to search for a novel agent with low risk of resistance development that can target QS and inflammatory damage prevention as well. Andrographis paniculata, a herbaceous plant under the family Acanthaceae, native to Asian countries and also cultivated in Scandinavia and some parts of Europe, has a strong traditional usage with its known antibacterial, anti-inflammatory, antipyretic, antiviral and antioxidant properties. In this study, three different solvent extracts (viz., chloroform, methanol and aqueous) of A. paniculata were examined for their anti-QS and anti-inflammatory activities. Study was carried out to assess the effect on some selected QS-regulatory genes at transcriptional level using Real Time-PCR. In addition, ability to attenuate MAPK pathways upon P. aeruginosa infection was performed to check its potential anti-inflammatory activity. Chloroform and methanol extracts showed significant reduction (p < 0.05) of the QS-controlled extracellular virulence factors in P. aeruginosa including the expression of pyocyanin, elastase, total protease, rhamnolipid and hemolysin without affecting bacterial viability. They also significantly (p < 0.05) reduced swarming motility and biofilm formation of P. aeruginosa. The chloroform extract, which was found to be more effective, decreased expression of lasI, lasR, rhlI and rhlR by 61%, 75%, 41%, and 44%, respectively. Moreover, chloroform extract decreased activation of p-p38 and p-ERK1/2 expression levels in MAPK signal pathways in P. aeruginosa infected macrophage cells. As the present study demonstrates that A. paniculata extracts inhibit QS in P. aeruginosa and exhibit anti-inflammatory activities, therefore it represents itself as a prospective therapeutic agent against P. aeruginosa infection.}, } @article {pmid29042186, year = {2018}, author = {Jamal, M and Ahmad, W and Andleeb, S and Jalil, F and Imran, M and Nawaz, MA and Hussain, T and Ali, M and Rafiq, M and Kamil, MA}, title = {Bacterial biofilm and associated infections.}, journal = {Journal of the Chinese Medical Association : JCMA}, volume = {81}, number = {1}, pages = {7-11}, doi = {10.1016/j.jcma.2017.07.012}, pmid = {29042186}, issn = {1728-7731}, mesh = {Bacterial Infections/etiology ; *Bacterial Physiological Phenomena ; *Biofilms ; Catheter-Related Infections/etiology ; Humans ; Urinary Catheters/microbiology ; }, abstract = {Microscopic entities, microorganisms that drastically affect human health need to be thoroughly investigated. A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living). Bacterial biofilms are usually pathogenic in nature and can cause nosocomial infections. The National Institutes of Health (NIH) revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation. The process of biofilm formation consists of many steps, starting with attachment to a living or non-living surface that will lead to formation of micro-colony, giving rise to three-dimensional structures and ending up, after maturation, with detachment. During formation of biofilm several species of bacteria communicate with one another, employing quorum sensing. In general, bacterial biofilms show resistance against human immune system, as well as against antibiotics. Health related concerns speak loud due to the biofilm potential to cause diseases, utilizing both device-related and non-device-related infections. In summary, the understanding of bacterial biofilm is important to manage and/or to eradicate biofilm-related diseases. The current review is, therefore, an effort to encompass the current concepts in biofilm formation and its implications in human health and disease.}, } @article {pmid29039290, year = {2017}, author = {Alfa, MJ and Singh, H and Nugent, Z and Duerksen, D and Schultz, G and Reidy, C and DeGagne, P and Olson, N}, title = {Simulated-Use Polytetrafluorethylene Biofilm Model: Repeated Rounds of Complete Reprocessing Lead to Accumulation of Organic Debris and Viable Bacteria.}, journal = {Infection control and hospital epidemiology}, volume = {38}, number = {11}, pages = {1284-1290}, doi = {10.1017/ice.2017.215}, pmid = {29039290}, issn = {1559-6834}, mesh = {*Biofilms ; Disinfection/methods ; Enterococcus faecalis ; Equipment Contamination ; Microscopy, Electron, Scanning ; Polytetrafluoroethylene/*chemistry ; Pseudomonas aeruginosa ; }, abstract = {OBJECTIVE Biofilm has been implicated in bacterial persistence and survival after endoscope reprocessing. In this study, we assessed the impact of different methods of reprocessing on organic residues and viable bacteria after repeated rounds of biofilm formation when each was followed by full reprocessing. METHODS ATS-2015, an artificial test soil containing 5-8 Log10 colony-forming units (CFU) of Enterococcus faecalis and Pseudomonas aeruginosa, was used to form biofilm in polytetrafluroethylene channels overnight on 5 successive days. Each successive day, full pump-assisted cleaning using bristle brushes or pull-through devices in combination with enzymatic or nonenzymatic detergents followed by fully automated endoscope reprocessor disinfection using peracetic acid was performed. Residuals were visualized by scanning electron microscopy (SEM). Destructive testing was used to assess expected cutoffs for adenosine triphosphate (ATP; <200 relative light units), protein (<2 µg/cm2), and viable bacteria count (0 CFU). RESULTS Protein residuals were above 2 µg/cm2, but ATP residuals were <200 relative light units for all methods tested. Only when enzymatic cleaner was used for cleaning were there no viable bacteria detected after disinfection irrespective of whether bristle brushes or pull-through devices were used. SEM revealed that some residual debris remained after all reprocessing methods, but more residuals were detected when a nonenzymatic detergent was used. CONCLUSIONS Surviving E. faecalis and P. aeruginosa were only detected when the non-enzymatic detergent was used, emphasizing the importance of the detergent used for endoscope channel reprocessing. Preventing biofilm formation is critical because not all current reprocessing methods can reliably eliminate viable bacteria within the biofilm matrix. Infect Control Hosp Epidemiol 2017;38:1284-1290.}, } @article {pmid29038256, year = {2018}, author = {Hufnagel, DA and Price, JE and Stephenson, RE and Kelley, J and Benoit, MF and Chapman, MR}, title = {Thiol Starvation Induces Redox-Mediated Dysregulation of Escherichia coli Biofilm Components.}, journal = {Journal of bacteriology}, volume = {200}, number = {1}, pages = {}, pmid = {29038256}, issn = {1098-5530}, support = {R01 GM118651/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cysteine/metabolism ; Escherichia coli Proteins/genetics/metabolism ; Extracellular Matrix/metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Oxidation-Reduction ; Periplasm/physiology ; Sulfhydryl Compounds/*metabolism ; Uropathogenic Escherichia coli/*metabolism ; }, abstract = {A hallmark of bacterial biofilms is the production of an extracellular matrix (ECM) that encases and protects the community from environmental stressors. Biofilm formation is an integral portion of the uropathogenic Escherichia coli (UPEC) life cycle. Approximately 2% of UPEC isolates are cysteine auxotrophs. Here, we investigated how cysteine homeostasis impacted UPEC UTI89 strain biofilm formation and, specifically, the production of the ECM components curli and cellulose. Cysteine auxotrophs produced less cellulose and slightly more curli compared to wild-type (WT) strains, and cysteine auxotrophs formed smooth, nonrugose colonies. Cellulose production was restored in cysteine auxotrophs when YfiR was inactivated. YfiR is a redox-sensitive regulator of the diguanylate cyclase, YfiN. The production of curli, a temperature-regulated appendage, was independent of temperature in UTI89 cysteine auxotrophs. In a screen of UPEC isolates, we found that ∼60% of UPEC cysteine auxotrophs produced curli at 37°C, but only ∼2% of cysteine prototrophic UPEC isolates produced curli at 37°C. Interestingly, sublethal concentrations of amdinocillin and trimethoprim-sulfamethoxazole inhibited curli production, whereas strains auxotrophic for cysteine continued to produce curli even in the presence of amdinocillin and trimethoprim-sulfamethoxazole. The dysregulation of ECM components and resistance to amdinocillin in cysteine auxotrophs may be linked to hyperoxidation, since the addition of exogenous cysteine or glutathione restored WT biofilm phenotypes to mutants unable to produce cysteine and glutathione.IMPORTANCE Uropathogenic Escherichia coli (UPEC) bacteria are the predominant causative agent of urinary tract infections (UTIs). UTIs account for billions of dollars of financial burden annually to the health care industry in the United States. Biofilms are an important aspect of the UPEC pathogenesis cascade and for the establishment of chronic infections. Approximately 2% of UPEC isolates from UTIs are cysteine auxotrophs, yet there is relatively little known about the biofilm formation of UPEC cysteine auxotrophs. Here we show that cysteine auxotrophs have dysregulated biofilm components due to a change in the redox state of the periplasm. Additionally, we show the relationship between cysteine auxotrophs, biofilms, and antibiotics frequently used to treat UTIs.}, } @article {pmid29038255, year = {2018}, author = {Sass, G and Nazik, H and Penner, J and Shah, H and Ansari, SR and Clemons, KV and Groleau, MC and Dietl, AM and Visca, P and Haas, H and Déziel, E and Stevens, DA}, title = {Studies of Pseudomonas aeruginosa Mutants Indicate Pyoverdine as the Central Factor in Inhibition of Aspergillus fumigatus Biofilm.}, journal = {Journal of bacteriology}, volume = {200}, number = {1}, pages = {}, pmid = {29038255}, issn = {1098-5530}, support = {W 1253/FWF_/Austrian Science Fund FWF/Austria ; }, mesh = {*Antibiosis ; Aspergillus fumigatus/*physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cystic Fibrosis/microbiology ; Humans ; Iron/metabolism ; *Mutation ; Oligopeptides/genetics/*metabolism ; Peptide Synthases/genetics/metabolism ; Pseudomonas aeruginosa/*genetics/pathogenicity/*physiology ; Trans-Activators/genetics/metabolism ; Virulence/genetics ; }, abstract = {Pseudomonas aeruginosa and Aspergillus fumigatus are common opportunistic bacterial and fungal pathogens, respectively. They often coexist in airways of immunocompromised patients and individuals with cystic fibrosis, where they form biofilms and cause acute and chronic illnesses. Hence, the interactions between them have long been of interest and it is known that P. aeruginosa can inhibit A. fumigatusin vitro We have approached the definition of the inhibitory P. aeruginosa molecules by studying 24 P. aeruginosa mutants with various virulence genes deleted for the ability to inhibit A. fumigatus biofilms. The ability of P. aeruginosa cells or their extracellular products produced during planktonic or biofilm growth to affect A. fumigatus biofilm metabolism or planktonic A. fumigatus growth was studied in agar and liquid assays using conidia or hyphae. Four mutants, the pvdD pchE, pvdD, lasR rhlR, and lasR mutants, were shown to be defective in various assays. This suggested the P. aeruginosa siderophore pyoverdine as the key inhibitory molecule, although additional quorum sensing-regulated factors likely contribute to the deficiency of the latter two mutants. Studies of pure pyoverdine substantiated these conclusions and included the restoration of inhibition by the pyoverdine deletion mutants. A correlation between the concentration of pyoverdine produced and antifungal activity was also observed in clinical P. aeruginosa isolates derived from lungs of cystic fibrosis patients. The key inhibitory mechanism of pyoverdine was chelation of iron and denial of iron to A. fumigatusIMPORTANCE Interactions between human pathogens found in the same body locale are of vast interest. These interactions could result in exacerbation or amelioration of diseases. The bacterium Pseudomonas aeruginosa affects the growth of the fungus Aspergillus fumigatus Both pathogens form biofilms that are resistant to therapeutic drugs and host immunity. P. aeruginosa and A. fumigatus biofilms are found in vivo, e.g., in the lungs of cystic fibrosis patients. Studying 24 P. aeruginosa mutants, we identified pyoverdine as the major anti-A. fumigatus compound produced by P. aeruginosa Pyoverdine captures iron from the environment, thus depriving A. fumigatus of a nutrient essential for its growth and metabolism. We show how microbes of different kingdoms compete for essential resources. Iron deprivation could be a therapeutic approach to the control of pathogen growth.}, } @article {pmid29037465, year = {2017}, author = {Prieto-Borja, L and Conde, A and Arenas, MA and de Damborenea, JJ and Esteban, J}, title = {Influence of exposure time on the release of bacteria from a biofilm on Ti6Al4V discs using sonication: An in vitro model.}, journal = {Diagnostic microbiology and infectious disease}, volume = {89}, number = {4}, pages = {258-261}, doi = {10.1016/j.diagmicrobio.2017.08.018}, pmid = {29037465}, issn = {1879-0070}, mesh = {Alloys ; Biofilms/*growth & development ; Colony Count, Microbial ; Enterococcus faecalis/growth & development/isolation & purification ; Escherichia coli/growth & development/isolation & purification ; Prostheses and Implants ; Prosthesis-Related Infections ; Pseudomonas aeruginosa/growth & development/isolation & purification ; *Sonication ; Staphylococcus aureus/growth & development/isolation & purification ; Staphylococcus epidermidis/growth & development/isolation & purification ; Time Factors ; Titanium/*chemistry ; }, abstract = {Implant sonication is considered a useful method for the diagnosis of implant-related infections. We designed an in vitro study using Ti6Al4V discs and 5 different bacteria to determine the optimal sonication time for recovery of most bacteria tested to enable use of sonication in clinical practice for microbiological diagnosis of implant-related infections. We carried out a specific protocol for the adherence and subsequent biofilm formation on the materials used. The discs were then sonicated and the retrieved bacteria were quantified. From minute 1 to 5, the amount of recovered organisms grew progressively for all bacteria. Between minute 6 and minute 10, the number was irregular for all strains except E. coli, though no pattern was evidenced. E. coli was the only microorganism with a progressive increase in liberation throughout the process. Significant differences were observed in each of the 10minutes analyzed as concerns the release of the 5 strains (P<0.021) as well as in the mean dislodgement (of the 10minutes) of all tested strains (P<0.00001). Considering that infections in which biofilms are involved could be polymicrobial, we concluded that 5minutes is the optimal time of sonication in order to recover the maximum amount of most bacteria attached to Ti6Al4V discs.}, } @article {pmid29035101, year = {2017}, author = {Wang, R and Schmidt, JW and Harhay, DM and Bosilevac, JM and King, DA and Arthur, TM}, title = {Biofilm Formation, Antimicrobial Resistance, and Sanitizer Tolerance of Salmonella enterica Strains Isolated from Beef Trim.}, journal = {Foodborne pathogens and disease}, volume = {14}, number = {12}, pages = {687-695}, doi = {10.1089/fpd.2017.2319}, pmid = {29035101}, issn = {1556-7125}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cattle ; Chlorine/pharmacology ; Chlorine Compounds/pharmacology ; Colony Count, Microbial ; Disinfectants/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Food Contamination ; Food Handling ; Food Microbiology ; Genotyping Techniques ; Oxides/pharmacology ; Quaternary Ammonium Compounds/pharmacology ; Red Meat/*microbiology ; Salmonella enterica/drug effects/*isolation & purification ; }, abstract = {In the beef industry, product contamination by Salmonella enterica is a serious public health concern, which may result in human infection and cause significant financial loss due to product recalls. Currently, the precise mechanism and pathogen source responsible for Salmonella contamination in commercial establishments are not well understood. We characterized 89 S. enterica strains isolated from beef trim with respect to their biofilm-forming ability, antimicrobial resistance, and biofilm cell survival/recovery growth after sanitizer exposure. A total of 28 Salmonella serovars was identified within these strains. The most common serovars identified were Anatum, Dublin, Montevideo, and Typhimurium, with these accounting for nearly half of the total strains. The vast majority (86%) of the strains was able to develop strong biofilms, and the biofilm-forming ability was highly strain dependent and related to cell surface expression of extracellular polymeric structures. These strains also demonstrated strong tolerance to quaternary ammonium chloride (QAC) and chlorine dioxide (ClO2), but were more sensitive to chlorine treatment. Sanitizer tolerance and bacterial postsanitization recovery growth were closely associated with strains' biofilm-forming ability. Thirty percent of the examined strains were found resistant to multiple antimicrobial agents and the resistance phenotypes were serovar associated, but not related to strains' biofilm-forming ability. Pulsed-field gel electrophoresis analysis tended to group strains by serovar rather than by biofilm-forming ability. Collectively, these data indicate that the strong biofilm formers of certain S. enterica strains/serovars possess significant potential for causing meat product contamination in meat processing environment.}, } @article {pmid29034850, year = {2017}, author = {Brock, MT and Fedderly, GC and Borlee, GI and Russell, MM and Filipowska, LK and Hyatt, DR and Ferris, RA and Borlee, BR}, title = {Pseudomonas aeruginosa variants obtained from veterinary clinical samples reveal a role for cyclic di-GMP in biofilm formation and colony morphology.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {11}, pages = {1613-1625}, doi = {10.1099/mic.0.000541}, pmid = {29034850}, issn = {1465-2080}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; Cats ; Ciprofloxacin/pharmacology ; Cyclic GMP/*analogs & derivatives/metabolism ; DNA Gyrase/genetics ; Dogs ; Drug Resistance, Bacterial/*genetics ; Escherichia coli Proteins/genetics ; Gene Expression ; Genome, Bacterial/genetics ; Gentamicins/pharmacology ; Horses ; Microbial Sensitivity Tests ; Mutation ; Phenotype ; Phosphoric Diester Hydrolases/genetics ; Phosphorus-Oxygen Lyases/genetics ; Pseudomonas aeruginosa/drug effects/enzymology/genetics/*physiology ; }, abstract = {Overuse of antibiotics is contributing to an emerging antimicrobial resistance crisis. To better understand how bacteria adapt tolerance and resist antibiotic treatment, Pseudomonas aeruginosa isolates obtained from infection sites sampled from companion animals were collected and evaluated for phenotypic differences. Selected pairs of clonal isolates were obtained from individual infection samples and were assessed for antibiotic susceptibility, cyclic di-GMP levels, biofilm production, motility and genetic-relatedness. A total of 18 samples from equine, feline and canine origin were characterized. A sample from canine otitis media produced a phenotypically heterogeneous pair of P. aeruginosa isolates, 42121A and 42121B, which during growth on culture medium respectively exhibited hyper dye-binding small colony morphology and wild-type phenotypes. Antibiotic susceptibility to gentamicin and ciprofloxacin also differed between this pair of clonal isolates. Sequence analysis of gyrA, a gene known to be involved in ciprofloxacin resistance, indicated that 42121A and 42121B both contained mutations that confer ciprofloxacin resistance, but this did not explain the differences in ciprofloxacin resistance that were observed. Cyclic di-GMP levels also varied between this pair of isolates and were shown to contribute to the observed colony morphology variation and ability to form a biofilm. Our results demonstrate the role of cyclic di-GMP in generating the observed morphological phenotypes that are known to contribute to biofilm-mediated antibiotic tolerance. The generation of phenotypic diversity may go unnoticed during standard diagnostic evaluation, which potentially impacts the therapeutic strategy chosen to treat the corresponding infection and may contribute to the spread of antibiotic resistance.}, } @article {pmid29033275, year = {2018}, author = {Mauch, RM and Jensen, PØ and Moser, C and Levy, CE and Høiby, N}, title = {Mechanisms of humoral immune response against Pseudomonas aeruginosa biofilm infection in cystic fibrosis.}, journal = {Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society}, volume = {17}, number = {2}, pages = {143-152}, doi = {10.1016/j.jcf.2017.08.012}, pmid = {29033275}, issn = {1873-5010}, mesh = {*Biofilms ; Cystic Fibrosis/*immunology/microbiology/therapy ; Humans ; *Immunity, Humoral ; Pseudomonas Infections/etiology/*prevention & control ; *Pseudomonas aeruginosa ; Respiratory Tract Infections/etiology/*prevention & control ; }, abstract = {P. aeruginosa chronic lung infection is the major cause of morbidity and mortality in patients with cystic fibrosis (CF), and is characterized by a biofilm mode of growth, increased levels of specific IgG antibodies and immune complex formation. However, despite being designed to combat this infection, such elevated humoral response is not associated with clinical improvement, pointing to a lack of anti-pseudomonas effectiveness. The mode of action of specific antibodies, as well as their structural features, and even the background involving B-cell production, stimulation and differentiation into antibody-producing cells in the CF airways are poorly understood. Thus, the aim of this review is to discuss studies that have addressed the intrinsic features of the humoral immune response and provide new insights regarding its insufficiency in the CF context.}, } @article {pmid29032227, year = {2017}, author = {Rosa, RAD and Santini, MF and Figueiredo, JAP and Visioli, F and Pereira, JR and Vivan, RR and Montagner, F and Só, MVR}, title = {Effectiveness of photodynamic therapy associated with irrigants over two biofilm models.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {20}, number = {}, pages = {169-174}, doi = {10.1016/j.pdpdt.2017.10.003}, pmid = {29032227}, issn = {1873-1597}, mesh = {Animals ; Bicuspid/microbiology ; Biofilms/*drug effects ; Cattle ; Chlorhexidine/*therapeutic use ; Colony-Forming Units Assay ; Dentin/microbiology ; Enterococcus faecalis/*drug effects ; Humans ; Microscopy, Confocal ; Photochemotherapy/*methods ; Root Canal Irrigants/*therapeutic use ; Sodium Hypochlorite/*therapeutic use ; }, abstract = {BACKGROUND: This study aimed to evaluate the antibacterial effect and the biofilm disruption promoted by antimicrobial photodynamic therapy (aPDT) associated with sodium hypochlorite (NaOCl) and chlorexidine (CHX) over monospecies and multispecies biofilms.

METHODS: In monospecies model, forty-six premolars were inoculated with Enterococcus faecalis for 21days and divided into three groups: saline, CHX and NaOCl. After irrigation, aPDT was performed. Samples were collected at baseline (S1) and after irrigation (S2) and aPDT (S3). Colony-forming unit (CFU) counts were performed. In multispecies model, sixty bovine dentin blocks were infected intraorally for 72h and divided into six groups: saline, saline/aPDT, CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. The percentage and the biovolume of live cells and the total biovolume were assessed using confocal laser scanning microscopy.

RESULTS: CHX and NaOCl showed the lowest CFU counts (P<0.05). aPDT reduced the bacterial counts in saline (S2-S3; P<0.05). The lowest amount of live cells was observed in CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. aPDT did not reduce the total biovolume (P>0.05).

CONCLUSION: aPDT associated with saline reduced the bacterial load in root canals infected with E. faecalis. aPDT did not reduce the total biovolume in situ; however, the irrigant was decisive to disrupt multispecies biofilms.}, } @article {pmid29032178, year = {2018}, author = {Mauch, RM and Nørregaard, LL and Ciofu, O and Levy, CE and Høiby, N}, title = {IgG avidity to Pseudomonas aeruginosa over the course of chronic lung biofilm infection in cystic fibrosis.}, journal = {Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society}, volume = {17}, number = {3}, pages = {356-359}, doi = {10.1016/j.jcf.2017.09.004}, pmid = {29032178}, issn = {1873-5010}, mesh = {Adolescent ; Adult ; *Biofilms ; Child ; Chronic Disease ; *Cystic Fibrosis/immunology/microbiology ; Denmark ; Female ; Humans ; Immunity, Humoral ; Immunoglobulin G/*blood ; Male ; *Pseudomonas Infections/diagnosis/immunology/physiopathology ; *Pseudomonas aeruginosa/isolation & purification/physiology ; Reproducibility of Results ; }, abstract = {BACKGROUND AND OBJECTIVES: The mechanisms leading to low effectiveness of the humoral immune response against P. aeruginosa in cystic fibrosis (CF) are poorly understood. The aim of the present study was to assess the avidity maturation of specific antipseudomonal IgG before and during the development of chronic lung infection in a cohort of Danish CF patients.

METHODS: Avidity maturation was assessed against a pooled P. aeruginosa antigen (St-Ag) and against P. aeruginosa alginate in 10 CF patients who developed chronic lung infection and 10 patients who developed intermittent lung colonization, using an ELISA technique with the thiocyanate elution method. Avidity was quantitatively determined by calculating the avidity Constant (Kav).

RESULTS: IgG avidity to St-Ag significantly increased at the onset (Median Kav=2.47) and one year after the onset of chronic infection (Median Kav=3.27), but did not significantly changed in patients who developed intermittent colonization. IgG avidity against alginate did not significantly change over the years neither in patients who developed chronic lung infection (Median Kav=3.84 at the onset of chronic infection), nor in patients who developed intermittent colonization.

CONCLUSION: IgG avidity to P. aeruginosa alginate does not significantly enhance as chronic lung infection progresses. This probably plays a role in the difficulty to mount an effective opsonophagocytic killing to clear mucoid P. aeruginosa infection in CF.}, } @article {pmid29031238, year = {2018}, author = {Hartenbach, FARR and Silva-Boghossian, CM and Colombo, APV}, title = {The effect of supragingival biofilm re-development on the subgingival microbiota in chronic periodontitis.}, journal = {Archives of oral biology}, volume = {85}, number = {}, pages = {51-57}, doi = {10.1016/j.archoralbio.2017.10.007}, pmid = {29031238}, issn = {1879-1506}, mesh = {Adult ; Biofilms/*growth & development ; Case-Control Studies ; Chronic Periodontitis/*microbiology ; Dental Prophylaxis ; Female ; Gingival Crevicular Fluid/metabolism ; Humans ; Male ; *Microbiota ; Middle Aged ; Oral Hygiene ; Periodontal Index ; }, abstract = {OBJECTIVE: In this study, we hypothesized that in the absence of oral hygiene, re-growth of the climax microbial communities of supra and subgingival biofilm happens in a faster and more intense fashion in individuals with chronic periodontitis (CP) compared to periodontally healthy controls (PH).

DESIGN: Thirty patients (PH=15 and CP=15) received professional supragingival prophylaxis, and were asked to refrain from oral hygiene for 7days. Supra and subgingival biofilm samples and GCF were collected from randomly selected quadrants at baseline (before prophylaxis), immediately after prophylaxis, 2h, 6h, 24h, and 7days after prophylaxis. The composition of the biofilm was determined by the checkerboard method.

RESULTS: All subjects developed gingivitis at the end of 7days without oral hygiene. GCF mean volumes were significantly higher in CP than PH patients at baseline, but they started decreasing 2h after prophylaxis, returning to baseline levels after 24h in both groups. Significant increases in mean counts for most of the species evaluated were observed in both groups and biofilms over time (p<0.05). Few hours after prophylaxis, a more marked reduction in microbial counts happened in the supragingival biofilm of the CP group, and re-development of biofilm started later than in the PH group. At 7days, no differences were seen between groups. Significant differences in kinetics of re-colonization between groups were observed only in the subgingival biofilm for T. denticola and F. nucleatum ss vicentii (increased in the CP), and N. mucosa (increased in the PH group; p<0.05).

CONCLUSIONS: Biofilm re-development was very similar between CP and PH individuals, although microbial re-growth occurred few hours earlier in PH than PC. Only 3 species in the subgingival biofilm differed in re-colonization between groups. Thus, we reject the hypothesis that re-colonization of biofilm in CP patients is more intense and faster than in individuals with PH.}, } @article {pmid29031236, year = {2018}, author = {Tan, Y and Leonhard, M and Moser, D and Ma, S and Schneider-Stickler, B}, title = {Inhibitory effect of probiotic lactobacilli supernatants on single and mixed non-albicans Candida species biofilm.}, journal = {Archives of oral biology}, volume = {85}, number = {}, pages = {40-45}, doi = {10.1016/j.archoralbio.2017.10.002}, pmid = {29031236}, issn = {1879-1506}, mesh = {Antibiosis/*drug effects ; Biofilms/*drug effects/*growth & development ; Candida/*drug effects ; Cell Survival/drug effects ; *Lactobacillus ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Probiotics/*pharmacology ; }, abstract = {OBJECTIVES: Oral candidiasis is one of the most common human fungal infections. While most cases of the Candida species isolated from the oral cavity are Candida albicans, a large number of candidiasis is attributed to non-albicans Candida species. In this study, we aim to evaluate the in vitro inhibition of supernatants of Lactobacillus gasseri and Lactobacillus rhamnosus on the single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Candida krusei and Candida parapsilosis.

DESIGN: Cell-free supernatants of Lactobacillus gasseri and Lactobacillus rhamnosus were prepared. Single and mixed non-albicans Candida species biofilm were formed in the 96-well microplate and on the surfaces of medical grade silicone. Biomass and cell viability were tested with crystal violet and cell counting kit-8. In order to examine the ability of the supernatant to disrupt pre-formed biofilm, supernatant was added to 24h-old biofilms. Biofilm architecture on silicone was investigated by scanning electron microscopy and confocal laser scanning microscopy was used to examine live/dead organisms within biofilm.

RESULTS: Single and mixed species biofilms and cell viability of non-albicans Candida biofilms were inhibited by probiotic lactobacilli supernatants. Matrue biofilm formation was disrupted by lactobacilli supernatants added at 24h after biofilm initiation. Examination with confocal laser scanning microscopy and scanning electron microscopy confirmed that lactobacilli supernatants inhibited the mixed biofilms and damaged the cells.

CONCLUSIONS: Our data elucidate the inhibitory activity of probiotic lactobacilli on non-albicans Candida biofilm, so as to support their utility as an adjunctive therapeutic mode against oral candida infections.}, } @article {pmid29030956, year = {2017}, author = {Heacock-Kang, Y and Sun, Z and Zarzycki-Siek, J and McMillan, IA and Norris, MH and Bluhm, AP and Cabanas, D and Fogen, D and Vo, H and Donachie, SP and Borlee, BR and Sibley, CD and Lewenza, S and Schurr, MJ and Schweizer, HP and Hoang, TT}, title = {Spatial transcriptomes within the Pseudomonas aeruginosa biofilm architecture.}, journal = {Molecular microbiology}, volume = {106}, number = {6}, pages = {976-985}, pmid = {29030956}, issn = {1365-2958}, support = {P30 GM114737/GM/NIGMS NIH HHS/United States ; R01 GM103580/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Drosophila/genetics ; *Gene Expression Regulation, Bacterial ; Mice ; Mutation ; Pseudomonas aeruginosa/*genetics/*pathogenicity ; Transcriptome ; Virulence Factors/genetics ; }, abstract = {Bacterial cooperative associations and dynamics in biofilm microenvironments are of special interest in recent years. Knowledge of localized gene-expression and corresponding bacterial behaviors within the biofilm architecture at a global scale has been limited, due to a lack of robust technology to study limited number of cells in stratified layers of biofilms. With our recent pioneering developments in single bacterial cell transcriptomic analysis technology, we generated herein an unprecedented spatial transcriptome map of the mature in vitro Pseudomonas aeruginosa biofilm model, revealing contemporaneous yet altered bacterial behaviors at different layers within the biofilm architecture (i.e., surface, middle and interior of the biofilm). Many genes encoding unknown functions were highly expressed at the biofilm-solid interphase, exposing a critical gap in the knowledge of their activities that may be unique to this interior niche. Several genes of unknown functions are critical for biofilm formation. The in vivo importance of these unknown proteins was validated in invertebrate (fruit fly) and vertebrate (mouse) models. We envisage the future value of this report to the community, in aiding the further pathophysiological understanding of P. aeruginosa biofilms. Our approach will open doors to the study of bacterial functional genomics of different species in numerous settings.}, } @article {pmid29030939, year = {2018}, author = {Kouba, V and Darmal, R and Vejmelkova, D and Jenicek, P and Bartacek, J}, title = {Cold shocks of Anammox biofilm stimulate nitrogen removal at low temperatures.}, journal = {Biotechnology progress}, volume = {34}, number = {1}, pages = {277-281}, doi = {10.1002/btpr.2570}, pmid = {29030939}, issn = {1520-6033}, mesh = {Ammonium Compounds/*chemistry ; Anaerobiosis/genetics ; Bacteria/genetics/growth & development/metabolism ; Biofilms/*growth & development ; Bioreactors ; Cold Temperature ; Cold-Shock Response/*genetics ; Denitrification/genetics ; In Situ Hybridization, Fluorescence ; Nitrogen/*metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/methods ; Water Purification/methods ; }, abstract = {The adaptation of Anammox (ANaerobic AMMonium OXidation) to low temperatures (10-15°C) is crucial for sustaining energy-efficient nitrogen removal from the mainstream of municipal wastewater. But, current adaptation methods take months or even years. To speed up the adaption of Anammox to low temperatures, this study describes a new approach: exposing Anammox microorganisms to an abrupt temporary reduction of temperature, i.e., cold shock. Anammox biomass in a moving bed biofilm reactor was subjected to three consecutive cold shocks (reduction from 24 ± 2 to 5.0 ± 0.2°C), each taking eight hours. Before the cold shocks, Anammox activity determined in ex situ tests using the temperature range of 12.5-19.5°C was 0.005-0.015 kg-N kg-VSS[-1] day[-1] . Cold shocks increased the activity of Anammox at 10°C to 0.054 kg-N kg-VSS[-1] day[-1] after the third shock, which is similar to the highest activities obtained for cold-enriched or adapted Anammox reported in the literature (0.080 kg-N kg-VSS[-1] day[-1]). Fluorescence in situ hybridization analysis showed that Ca. Brocadia fulgida was the dominant species. Thus, cold shocks are an intriguing new strategy for the adaptation of Anammox to low temperature. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:277-281, 2018.}, } @article {pmid29030437, year = {2017}, author = {Slany, M and Oppelt, J and Cincarova, L}, title = {Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq).}, journal = {Applied and environmental microbiology}, volume = {83}, number = {24}, pages = {}, pmid = {29030437}, issn = {1098-5336}, mesh = {Biofilms/*drug effects ; Chloramines/pharmacology ; Disinfectants/*pharmacology ; Ethanol/pharmacology ; Gene Expression Profiling ; Sequence Analysis, RNA ; Staphylococcus aureus/*drug effects/genetics/*physiology ; *Transcriptome ; }, abstract = {Staphylococcus aureus is a common biofilm-forming pathogen. Low doses of disinfectants have previously been reported to promote biofilm formation and to increase virulence. The aim of this study was to use transcriptome sequencing (RNA-seq) analysis to investigate global transcriptional changes in S. aureus in response to sublethal concentrations of the commonly used food industry disinfectants ethanol (EtOH) and chloramine T (ChT) and their combination (EtOH_ChT) in order to better understand the effects of these agents on biofilm formation. Treatment with EtOH and EtOH_ChT resulted in more significantly altered expression profiles than treatment with ChT. Our results revealed that EtOH and EtOH_ChT treatments enhanced the expression of genes responsible for regulation of gene expression (sigB), cell surface factors (clfAB), adhesins (sdrDE), and capsular polysaccharides (cap8EFGL), resulting in more intact biofilm. In addition, in this study we were able to identify the pathways involved in the adaptation of S. aureus to the stress of ChT treatment. Further, EtOH suppressed the effect of ChT on gene expression when these agents were used together at sublethal concentrations. These data show that in the presence of sublethal concentrations of tested disinfectants, S. aureus cells trigger protective mechanisms and try to cope with them.IMPORTANCE So far, the effect of disinfectants is not satisfactorily explained. The presented data will allow a better understanding of the mode of disinfectant action with regard to biofilm formation and the ability of bacteria to survive the treatment. Such an understanding could contribute to the effort to eliminate possible sources of bacteria, making disinfectant application as efficient as possible. Biofilm formation plays significant role in the spread and pathogenesis of bacterial species.}, } @article {pmid29028629, year = {2018}, author = {Pires, PM and Santos, TPD and Fonseca-Gonçalves, A and Pithon, MM and Lopes, RT and Neves, AA}, title = {A dual energy micro-CT methodology for visualization and quantification of biofilm formation and dentin demineralization.}, journal = {Archives of oral biology}, volume = {85}, number = {}, pages = {10-15}, doi = {10.1016/j.archoralbio.2017.09.034}, pmid = {29028629}, issn = {1879-1506}, mesh = {*Biofilms ; Dental Caries/microbiology ; Humans ; In Vitro Techniques ; Molar, Third ; Saliva/microbiology ; Surface Properties ; Tooth Demineralization/*diagnostic imaging ; X-Ray Microtomography/*methods ; }, abstract = {OBJECTIVE: The aim of this study was to induce artificial caries in human sound dentin by means of a microcosm model using human saliva as source of bacteria and to apply a novel dual-energy micro-CT technique to quantify biofilm formation and evaluate its demineralization potential.

DESIGN: Eight sound third molars had the occlusal enamel removed by cutting with a diamond disk and five cylindrical cavities (±2mm diameter; ±1.5mm depth) were prepared over the dentin surface in each specimen (n=40 cavities). After sterilization, each specimen received the bacterial salivary inoculum obtained from individuals without any systemic diseases presenting dentin caries lesions and were incubated in BHI added of with 5% sucrose for 96h to allow biofilm formation. After that, two consecutive micro-CT scans were acquired from each specimen (40kv and 70kv). Reconstruction of the images was performed using standardized parameters. After alignment, registration, filtering and image calculations, a final stack of images containing the biofilm volume was obtained from each prepared cavity. Dentin demineralization degree was quantified by comparison with sound dentin areas. All data were analyzed using Shapiro-Wilk test and Spearman correlation using α=5%.

RESULTS: Dual-energy micro-CT technique disclosed biofilm formation in all cavities. Biofilm volume inside each cavity varied from 0.30 to 1.57mm[3]. A positive correlation between cavity volume and volume of formed biofilm was obtained (0.77, p<0.01). The mineral decrease obtained in dentin was high (±90%) for all cavities and all demineralized areas showed mineral density values lower than a defined threshold for dentin caries (1.2g/cm[3]).

CONCLUSION: Dual-energy micro-CT technique was successful in the quantification of a microcosm human bacterial biofilm formation and to quantify its demineralization potential in vitro.}, } @article {pmid29027389, year = {2017}, author = {Lee, Y}, title = {Biofilm Formation and Antimicrobial Resistance in Enterococcus.}, journal = {Infection & chemotherapy}, volume = {49}, number = {3}, pages = {236-237}, pmid = {29027389}, issn = {2093-2340}, } @article {pmid29027384, year = {2017}, author = {Saffari, F and Dalfardi, MS and Mansouri, S and Ahmadrajabi, R}, title = {Survey for Correlation between Biofilm Formation and Virulence Determinants in a Collection of Pathogenic and Fecal Enterococcus faecalis Isolates.}, journal = {Infection & chemotherapy}, volume = {49}, number = {3}, pages = {176-183}, pmid = {29027384}, issn = {2093-2340}, abstract = {BACKGROUND: Enterococcus faecalis is an opportunistic pathogen that causes most of the enterococcal infections. Among the different factors implicated in the pathogenesis of these organisms, biofilm formation and antibiotic resistance are the most important. The ability for biofilm formation has been attributed to the presence of some virulence genes. However, no definite correlation has been found. This study aimed to detect biofilm formation and antibiotic resistance patterns in E. faecalis isolates collected from clinical and fecal samples, and to investigate possible correlation between some virulence genes (esp, cyl, gelE) and biofilm formation.

MATERIALS AND METHODS: A collection of 123 E. faecalis isolates were investigated for antibiotic resistance and production of hemolysin, gelatinase, and biofilm using phenotypic methods. The esp, gelE and cyl genes were detected using polymerase chain reaction.

RESULTS: Thirty-eight pathogenic isolates (37%) were positive for biofilm formation. Additionally, the gelE, esp, and cyl genes were detected in 74 (71.8%), 79 (76.7%) and 42 (40.8%) isolates, respectively. In the fecal samples, 18 (90%) isolates were biofilm producers and 11 (55%), 17 (85%) and 8 (40%) isolates were positive for gelE, esp, and cyl, respectively. There were significant differences in biofilm production between pathogenic and fecal isolates (P <0.001). Multidrug resistance (MDR) was found among 32% (n = 33) and 15% (n = 3) of the clinical and fecal isolates, respectively. However, no significant difference was seen between MDR and biofilm formation. Five pathogenic and two fecal isolates were negative for all investigated genes while they were they were biofilm producers. In contrast, 22 pathogenic isolates and 1 fecal isolate were positive for the tested genes, but did not form any biofilm. No significant differences were observed between biofilm formation and the presence of the esp, gelE and cyl genes in the pathogenic and fecal isolates (P >0.05).

CONCLUSION: The presence of the esp, gelE and cyl genes might not be determining factors for biofilm formation in enterococci and other mechanisms might be involved in this process.}, } @article {pmid29026191, year = {2017}, author = {Johnson, CJ and Kernien, JF and Hoyer, AR and Nett, JE}, title = {Mechanisms involved in the triggering of neutrophil extracellular traps (NETs) by Candida glabrata during planktonic and biofilm growth.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {13065}, pmid = {29026191}, issn = {2045-2322}, support = {K08 AI108727/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Candida glabrata/*physiology ; Cells, Cultured ; Extracellular Traps/*metabolism ; Humans ; Microscopy, Electron, Scanning ; Neutrophils/metabolism/ultrastructure ; Plankton/*microbiology ; Rats ; Reactive Oxygen Species/metabolism ; }, abstract = {Candida spp. adhere to medical devices, such as catheters, forming drug-tolerant biofilms that resist killing by the immune system. Little is known about how C. glabrata, an emerging pathogen, resists attack by phagocytes. Here we show that upon encounter with planktonic (non-biofilm) C. glabrata, human neutrophils initially phagocytose the yeast and subsequently release neutrophil extracellular traps (NETs), complexes of DNA, histones, and proteins capable of inhibiting fungal growth and dissemination. When exposed to C. glabrata biofilms, neutrophils also release NETs, but significantly fewer than in response to planktonic cells. Impaired killing of biofilm parallels the decrease in NET production. Compared to biofilm, neutrophils generate higher levels of reactive oxygen species (ROS) when presented with planktonic organisms, and pharmacologic inhibition of NADPH-oxidase partially impairs NET production. In contrast, inhibition of phagocytosis nearly completely blocks NET release to both biofilm and planktonic organisms. Imaging of the host response to C. glabrata in a rat vascular model of infection supports a role for NET release in vivo. Taken together, these findings show that C. glabrata triggers NET release. The diminished NET response to C. glabrata biofilms likely contributes to the resilience of these structured communities to host defenses.}, } @article {pmid29025936, year = {2017}, author = {Yu, L and Hisatsune, J and Hirakawa, H and Mizumachi, E and Toyoda, A and Yahara, K and Sugai, M}, title = {Complete Genome Sequence of Super Biofilm-Elaborating Staphylococcus aureus Isolated in Japan.}, journal = {Genome announcements}, volume = {5}, number = {41}, pages = {}, pmid = {29025936}, issn = {2169-8287}, abstract = {Staphylococcus aureus JP080, previously named TF2758, is a clinical isolate from an atheroma and a super biofilm-elaborating strain whose biofilm elaboration is dependent solely on polysaccharide poly-N-acetylglucosamine/polysaccharide intercellular adhesin (PNAG/PIA). Here, we report the complete genome sequence of strain JP080, which consists of one chromosome and one circular plasmid.}, } @article {pmid29025650, year = {2018}, author = {Lefebvre, E and Lembre, P and Picard, J and El-Guermah, L and Seyer, D and Larreta Garde, V}, title = {Ephemeral biogels to control anti-biofilm agent delivery: From conception to the construction of an active dressing.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {82}, number = {}, pages = {210-216}, doi = {10.1016/j.msec.2017.07.044}, pmid = {29025650}, issn = {1873-0191}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Bandages ; Biguanides/*chemistry/pharmacology ; Biofilms/*drug effects ; Edetic Acid/*chemistry/pharmacology ; Gelatin/chemistry ; Gels/*chemistry ; Pseudomonas aeruginosa/physiology ; Rheology ; Staphylococcus aureus/physiology ; }, abstract = {Chronic wound colonization by bacterial biofilms is common and can cause various complications. An anti-biofilm strategy was developed around the co-entrapment of a commercially available antiseptic, PHMB (polyhexamethylene biguanide 4mgmL[-1]), with EDTA (Ethylen diamine tetra acetic acid, 20mM) in a gelatin gel. The two active compounds act synergistically against bacterial biofilms, but their efficiency is strongly reduced (16-fold) when entrapped inside the 5% gelatin gel, and they weaken the mechanical properties (50-fold) of the gel. Increasing the gelatin concentration to 7% allows for good mechanical properties but large diffusional constraints. An active ephemeral gel, a chemical gel with controlled hydrolysis, was conceived and developed. When the ephemeral gel was solubilized after 48h, PHMB delivery increased, leading to good anti-biofilm activity. The various gels were examined over 24 and 48h of contact with P. aeruginosa and S. aureus biofilms, two types of bacterial biofilms frequently encountered in chronic wounds. The ephemeral gel eradicated the dense biofilms (>6.10[7]CFU·cm[-2]) produced by either single or mixed strains; a similar efficiency was measured for biofilms from strains of both laboratory and clinical origin. The formulation was then adapted to develop a dressing prototype that is active against biofilms and fulfils the requirements of an efficient wound care system.}, } @article {pmid29025642, year = {2018}, author = {Geng, H and Yuan, Y and Adayi, A and Zhang, X and Song, X and Gong, L and Zhang, X and Gao, P}, title = {Engineered chimeric peptides with antimicrobial and titanium-binding functions to inhibit biofilm formation on Ti implants.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {82}, number = {}, pages = {141-154}, doi = {10.1016/j.msec.2017.08.062}, pmid = {29025642}, issn = {1873-0191}, mesh = {Anti-Infective Agents/*chemistry/*pharmacology ; Biofilms/drug effects ; Cell Line ; Humans ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; Peptides/*chemistry ; Streptococcus gordonii/drug effects ; Streptococcus oralis/drug effects ; Streptococcus sanguis/drug effects ; Titanium/*chemistry/*pharmacology ; beta-Defensins/metabolism ; }, abstract = {Titanium (Ti) implants have been commonly used in oral medicine. However, despite their widespread clinical application, these implants are susceptible to failure induced by microbial infection due to bacterial biofilm formation. Immobilization of chimeric peptides with antibacterial properties on the Ti surface may be a promising antimicrobial approach to inhibit biofilm formation. Here, chimeric peptides were designed by connecting three sequences (hBD-3-1/2/3) derived from human β-defensin-3 (hBD-3) with Ti-binding peptide-l (TBP-l: RKLPDAGPMHTW) via a triple glycine (G) linker to modify Ti surfaces. Using X-ray photoelectron spectroscopy (XPS), the properties of individual domains of the chimeric peptides were evaluated for their binding activity toward the Ti surface. The antimicrobial and anti-biofilm efficacy of the peptides against initial settlers, Streptococcus oralis (S. oralis), Streptococcus gordonii (S. gordonii) and Streptococcus sanguinis (S. sanguinis), was evaluated with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Transmission electron microscopy (TEM) and real-time quantitative PCR (qRT-PCR) were used to study cell membrane changes and the underlying antimicrobial mechanism. Compared with the other two peptides, TBP-1-GGG-hBD3-3 presented stronger antibacterial activity and remained stable in saliva and serum. Therefore, it was chosen as the best candidate to modify Ti surfaces in this study. This peptide inhibited the growth of initial streptococci and biofilm formation on Ti surfaces with no cytotoxicity to MC3T3-E1 cells. Disruption of the integrity of bacterial membranes and decreased expression of adhesion protein genes from S. gordonii revealed aspects of the antibacterial mechanism of TBP-1-GGG-hBD3-3. We conclude that engineered chimeric peptides with antimicrobial activity provide a potential solution for inhibiting biofilm formation on Ti surfaces to reduce or prevent the occurrence of peri-implant diseases.}, } @article {pmid29025325, year = {2018}, author = {Meeker, DG and Wang, T and Harrington, WN and Zharov, VP and Johnson, SA and Jenkins, SV and Oyibo, SE and Walker, CM and Mills, WB and Shirtliff, ME and Beenken, KE and Chen, J and Smeltzer, MS}, title = {Versatility of targeted antibiotic-loaded gold nanoconstructs for the treatment of biofilm-associated bacterial infections.}, journal = {International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group}, volume = {34}, number = {2}, pages = {209-219}, pmid = {29025325}, issn = {1464-5157}, support = {UL1 TR000039/TR/NCATS NIH HHS/United States ; R56 AI093126/AI/NIAID NIH HHS/United States ; P20 GM103625/GM/NIGMS NIH HHS/United States ; T32 GM106999/GM/NIGMS NIH HHS/United States ; P30 GM103450/GM/NIGMS NIH HHS/United States ; P30 GM145393/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bacterial Infections/pathology/*therapy ; Biofilms ; Gold/*metabolism ; Humans ; Nanoparticles/*metabolism ; }, abstract = {BACKGROUND: We previously demonstrated that a photoactivatable therapeutic approach employing antibiotic-loaded, antibody-conjugated, polydopamine (PDA)-coated gold nanocages (AuNCs) could be used for the synergistic killing of bacterial cells within a biofilm. The approach was validated with a focus on Staphylococcus aureus using an antibody specific for staphylococcal protein A (Spa) and an antibiotic (daptomycin) active against Gram-positive cocci including methicillin-resistant S. aureus (MRSA). However, an important aspect of this approach is its potential therapeutic versatility.

METHODS: In this report, we evaluated this versatility by examining the efficacy of AuNC formulations generated with alternative antibodies and antibiotics targeting S. aureus and alternative combinations targeting the Gram-negative pathogen Pseudomonas aeruginosa.

RESULTS: The results confirmed that daptomycin-loaded AuNCs conjugated to antibodies targeting two different S. aureus lipoproteins (SACOL0486 and SACOL0688) also effectively kill MRSA in the context of a biofilm. However, our results also demonstrate that antibiotic choice is critical. Specifically, ceftaroline and vancomycin-loaded AuNCs conjugated to anti-Spa antibodies were found to exhibit reduced efficacy relative to daptomycin-loaded AuNCs conjugated to the same antibody. In contrast, gentamicin-loaded AuNCs conjugated to an antibody targeting a conserved outer membrane protein were highly effective against P. aeruginosa biofilms.

CONCLUSIONS: These results confirm the therapeutic versatility of our approach. However, to the extent that its synergistic efficacy is dependent on the ability to achieve both a lethal photothermal effect and the thermally controlled release of a sufficient amount of antibiotic, they also demonstrate the importance of carefully designing appropriate antibody and antibiotic combinations to achieve the desired therapeutic synergy.}, } @article {pmid29022382, year = {2018}, author = {Lagrafeuille, R and Miquel, S and Balestrino, D and Vareille-Delarbre, M and Chain, F and Langella, P and Forestier, C}, title = {Opposing effect of Lactobacillus on in vitro Klebsiella pneumoniae in biofilm and in an in vivo intestinal colonisation model.}, journal = {Beneficial microbes}, volume = {9}, number = {1}, pages = {87-100}, doi = {10.3920/BM2017.0002}, pmid = {29022382}, issn = {1876-2891}, mesh = {Animals ; *Antibiosis ; Bacterial Adhesion/genetics ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Coculture Techniques ; Fimbriae, Bacterial/genetics ; Gastrointestinal Tract/*microbiology ; Klebsiella pneumoniae/genetics/*growth & development ; Lactobacillus/classification/growth & development/physiology ; Lactobacillus plantarum/growth & development/metabolism/*physiology ; Mice ; Quorum Sensing/genetics ; Transcription, Genetic ; }, abstract = {Beneficial bacteria represent potential sources of therapy, particularly in the battle against antibiotic-resistant pathogens. The Gram-negative bacillus Klebsiella pneumoniae is not only a paradigm of multi-resistant opportunistic pathogen, but it is also able to colonise the human intestine and displays a high capacity to form biofilm. In this study, the anti-biofilm activity of 140 neutralised Lactobacillus supernatants was assessed against K. pneumoniae. Among the 13 strains whose supernatant significantly impaired biofilm formation, Lactobacillus plantarum CIRM653 was selected because it was also able to impair K. pneumoniae preformed biofilm, independently of a bactericidal effect. Mixed K. pneumoniae/L. plantarum CIRM653 biofilms had reduced tridimensional structures associated with a significant decrease in K. pneumoniae biomass. Further investigation showed that L. plantarum CIRM653 supernatant induced transcriptional modifications of K. pneumoniae biofilm-related genes, including down-regulation of the quorum sensing-related lsr operons and over-expression of type 3 pili structure genes. Increased production of type 3 pili was validated by Western-blot, hemagglutination and adhesion assays. L. plantarum CIRM653 activity against K. pneumoniae was also assessed in a murine intestinal colonisation model: a constant faecal pathogen burden was observed, as against a gradual decrease in the control group. These results reveal that an in vitro a priori attracting anti-biofilm activity of Lactobacillus might be counterbalanced by an in vivo behaviour in a complex microbiota environment with potential deleterious dispersal of highly adherent K. pneumoniae cells, raising the question of the accuracy of in vitro assays in screening of beneficial microbes.}, } @article {pmid29021602, year = {2017}, author = {York, A}, title = {Biofilms: The architect of the biofilm.}, journal = {Nature reviews. Microbiology}, volume = {15}, number = {11}, pages = {642-643}, pmid = {29021602}, issn = {1740-1534}, mesh = {Biofilms ; *Vibrio cholerae ; }, } @article {pmid29020439, year = {2017}, author = {Hwang, G and Koltisko, B and Jin, X and Koo, H}, title = {Nonleachable Imidazolium-Incorporated Composite for Disruption of Bacterial Clustering, Exopolysaccharide-Matrix Assembly, and Enhanced Biofilm Removal.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {44}, pages = {38270-38280}, doi = {10.1021/acsami.7b11558}, pmid = {29020439}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Composite Resins ; Imidazoles ; Methacrylates ; Streptococcus mutans ; }, abstract = {Surface-grown bacteria and production of an extracellular polymeric matrix modulate the assembly of highly cohesive and firmly attached biofilms, making them difficult to remove from solid surfaces. Inhibition of cell growth and inactivation of matrix-producing bacteria can impair biofilm formation and facilitate removal. Here, we developed a novel nonleachable antibacterial composite with potent antibiofilm activity by directly incorporating polymerizable imidazolium-containing resin (antibacterial resin with carbonate linkage; ABR-C) into a methacrylate-based scaffold (ABR-modified composite; ABR-MC) using an efficient yet simplified chemistry. Low-dose inclusion of imidazolium moiety (∼2 wt %) resulted in bioactivity with minimal cytotoxicity without compromising mechanical integrity of the restorative material. The antibiofilm properties of ABR-MC were assessed using an exopolysaccharide-matrix-producing (EPS-matrix-producing) oral pathogen (Streptococcus mutans) in an experimental biofilm model. Using high-resolution confocal fluorescence imaging and biophysical methods, we observed remarkable disruption of bacterial accumulation and defective 3D matrix structure on the surface of ABR-MC. Specifically, the antibacterial composite impaired the ability of S. mutans to form organized bacterial clusters on the surface, resulting in altered biofilm architecture with sparse cell accumulation and reduced amounts of EPS matrix (versus control composite). Biofilm topology analyses on the control composite revealed a highly organized and weblike EPS structure that tethers the bacterial clusters to each other and to the surface, forming a highly cohesive unit. In contrast, such a structured matrix was absent on the surface of ABR-MC with mostly sparse and amorphous EPS, indicating disruption in the biofilm physical stability. Consistent with lack of structural organization, the defective biofilm on the surface of ABR-MC was readily detached when subjected to low shear stress, while most of the biofilm biomass remained on the control surface. Altogether, we demonstrate a new nonleachable antibacterial composite with excellent antibiofilm activity without affecting its mechanical properties, which may serve as a platform for development of alternative antifouling biomaterials.}, } @article {pmid29018985, year = {2018}, author = {She, Z and Wu, L and Wang, Q and Gao, M and Jin, C and Zhao, Y and Zhao, L and Guo, L}, title = {Salinity effect on simultaneous nitrification and denitrification, microbial characteristics in a hybrid sequencing batch biofilm reactor.}, journal = {Bioprocess and biosystems engineering}, volume = {41}, number = {1}, pages = {65-75}, doi = {10.1007/s00449-017-1844-5}, pmid = {29018985}, issn = {1615-7605}, support = {51178437//National Natural Science Foundation of China/ ; }, mesh = {Biofilms/*growth & development ; Bioreactors/*microbiology ; *Denitrification ; *Nitrification ; *Salinity ; Sewage/*microbiology ; }, abstract = {The effect of increasing salinity on nitrogen removal via simultaneous nitrification and denitrification, microbial activities and extracellular polymeric substances (EPS) were investigated in a hybrid sequencing batch biofilm reactor filled with soft combination carriers. In the influent salinity range from 1.0 to 2.0%, average COD, NH4[+]-N and TN removal efficiencies were higher than 97.1, 97.8 and 86.4% at the steady state. When salinity was increased to 2.5 and 3.0%, ammonium oxidation was obviously inhibited in the reactor. For both suspended sludge (S-sludge) and biofilm, specific ammonium oxidation rate, specific nitrite oxidation rate, specific oxygen uptake rate and dehydrogenase activity reduced with the increase of salinity. The quantity of total EPS increased with the increase of salinity from 1.0 to 2.0%. Generally, humic substances were the dominant composition of EPS in both S-sludge and biofilm, with the percentages of 43.9-54.0 and 43.8-64.6% in total EPS.}, } @article {pmid29018977, year = {2018}, author = {Chen, HY and Liu, YD and Dong, B}, title = {Biodegradation of tetracycline antibiotics in A/O moving-bed biofilm reactor systems.}, journal = {Bioprocess and biosystems engineering}, volume = {41}, number = {1}, pages = {47-56}, doi = {10.1007/s00449-017-1842-7}, pmid = {29018977}, issn = {1615-7605}, support = {51008216//National Natural Science Foundation of China/ ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Tetracycline/*metabolism ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {An anaerobic/aerobic moving-bed biofilm (A/O-MBBR) reactor system was constructed, and the treatment efficiency of aqueous antibiotics in wastewater was investigated. The effects of antibiotics on the microbial communities in the A/O-MBBR were also investigated. Under the optimized reaction conditions, removal of tetracycline antibiotics (TCs) was studied in a series of experiments. When a low concentration of tetracycline (TC) was added to the reactor system, high removal efficiency of conventional pollutants (TC concentration decreased from 10 turn to 2.8 μg L[-1]) was achieved. When mixed TCs (50 μg L[-1]) were added to the system, the removal efficiencies of chlortetracycline (CTC), TC and oxytetracycline (OTC) reached 52.03, 41.79, and 38.42%, respectively. TC degradation was decreased to 21.16% when the antibiotic concentration was 500 μg L[-1]; exposure to this TC concentration destroyed the community structure of the activated sludge bacteria in the reactor. The products of the biodegradation analysis revealed the possible degradation pathways functioning in the experimental A/O-MBBRs.}, } @article {pmid29018430, year = {2017}, author = {Jia, K and Wang, G and Liang, L and Wang, M and Wang, H and Xu, X}, title = {Preliminary Transcriptome Analysis of Mature Biofilm and Planktonic Cells of Salmonella Enteritidis Exposure to Acid Stress.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1861}, pmid = {29018430}, issn = {1664-302X}, abstract = {Salmonella has emerged as a well-recognized food-borne pathogen, with many strains able to form biofilms and thus cause cross-contamination in food processing environments where acid-based disinfectants are widely encountered. In the present study, RNA sequencing was employed to establish complete transcriptome profiles of Salmonella Enteritidis in the forms of planktonic and biofilm-associated cells cultured in Tryptic Soytone Broth (TSB) and acidic TSB (aTSB). The gene expression patterns of S. Enteritidis significantly differed between biofilm-associated and planktonic cells cultivated under the same conditions. The assembled transcriptome of S. Enteritidis in this study contained 5,442 assembled transcripts, including 3,877 differentially expressed genes (DEGs) identified in biofilm and planktonic cells. These DEGs were enriched in terms such as regulation of biological process, metabolic process, macromolecular complex, binding and transferase activity, which may play crucial roles in the biofilm formation of S. Enteritidis cultivated in aTSB. Three significant pathways were observed to be enriched under acidic conditions: bacterial chemotaxis, porphyrin-chlorophyll metabolism and sulfur metabolism. In addition, 15 differentially expressed novel non-coding small RNAs (sRNAs) were identified, and only one was found to be up-regulated in mature biofilms. This preliminary study of the S. Enteritidis transcriptome serves as a basis for future investigations examining the complex network systems that regulate Salmonella biofilm in acidic environments, which provide information on biofilm formation and acid stress interaction that may facilitate the development of novel disinfection procedures in the food processing industry.}, } @article {pmid29018429, year = {2017}, author = {Liu, L and Wu, R and Zhang, J and Shang, N and Li, P}, title = {D-Ribose Interferes with Quorum Sensing to Inhibit Biofilm Formation of Lactobacillus paraplantarum L-ZS9.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1860}, pmid = {29018429}, issn = {1664-302X}, abstract = {Biofilms help bacteria survive under adverse conditions, and the quorum sensing (QS) system plays an important role in regulating their activities. Quorum sensing inhibitors (QSIs) have great potential to inhibit pathogenic biofilm formation and are considered possible replacements for antibiotics; however, further investigation is required to understand the mechanisms of action of QSIs and to avoid inhibitory effects on beneficial bacteria. Lactobacillus paraplantarum L-ZS9, isolated from fermented sausage, is a bacteriocin-producing bacteria that shows potential to be a probiotic starter. Since exogenous autoinducer-2 (AI-2) promoted biofilm formation of the strain, expression of genes involved in AI-2 production was determined in L. paraplantarum L-ZS9, especially the key gene luxS. D-Ribose was used to inhibit biofilm formation because of its AI-2 inhibitory activity. Twenty-seven differentially expressed proteins were identified by comparative proteomic analysis following D-ribose treatment and were functionally classified into six groups. Real-time quantitative PCR showed that AI-2 had a counteractive effect on transcription of the genes tuf, fba, gap, pgm, nfo, rib, and rpoN. Over-expression of the tuf, fba, gap, pgm, and rpoN genes promoted biofilm formation of L. paraplantarum L-ZS9, while over-expression of the nfo and rib genes inhibited biofilm formation. In conclusion, D-ribose inhibited biofilm formation of L. paraplantarum L-ZS9 by regulating multiple genes involved in the glycolytic pathway, extracellular DNA degradation and transcription, and translation. This research provides a new mechanism of QSI regulation of biofilm formation of Lactobacillus and offers a valuable reference for QSI application in the future.}, } @article {pmid28994493, year = {2017}, author = {Moradi, M and Tajik, H}, title = {Biofilm removal potential of neutral electrolysed water on pathogen and spoilage bacteria in dairy model systems.}, journal = {Journal of applied microbiology}, volume = {123}, number = {6}, pages = {1429-1437}, doi = {10.1111/jam.13608}, pmid = {28994493}, issn = {1365-2672}, mesh = {Animals ; Biofilms/drug effects ; Cattle ; Electrolysis ; Escherichia coli/drug effects/growth & development ; Food Contamination/analysis ; Hot Temperature ; Listeria monocytogenes/drug effects/growth & development ; Microbial Viability/drug effects ; Milk/*microbiology ; Pseudomonas aeruginosa/drug effects ; Temperature ; Water/*chemistry/*pharmacology ; }, abstract = {AIMS: This study aimed to investigate the efficacy of neutral electrolysed water (NEW) on biofilm and planktonic forms of Listeria monocytogenes, Escherichia coli and Pseudomonas aeruginosa in Luria-Bertani (LB) broth, 0·5 and 3% w/w fat pasteurized and ultra high temperature (UHT) milk.

METHODS AND RESULTS: Biofilm was established on stainless steels in a simulated industrial model biofilm reactor. NEW had a bactericidal effect on planktonic forms of all bacteria at 25 μg ml[-1] concentration. Biofilm production index (BPI) was affected by the type of media and micro-organisms and incubation temperatures. In general, biofilms were more intense at 22°C in milk containing 3% fat than 0·5% fat and LB. The highest BPI (1·12) was reported for the biofilm of E. coli at 22°C in 3% fat pasteurized milk. No significant change in biofilm formation for any bacteria at UHT and pasteurized milk was obtained. NEW at 75 μg ml[-1] concentration had more significant biofilm removal activity on all the tested bacteria. The biofilm removal property of NEW in high-fat milk was lower than that in low-fat milk and LB broth.

CONCLUSIONS: NEW can be used at 75 μg ml[-1] concentration as a sanitizing and biofilm removal compound in dairy plant facilities.

This study highlighted the effect of different growth media, including culture media and different types of milk, and the biofilm removal activity of NEW on foodborne pathogens and spoilage bacteria which could be considered in plant sanitation schedule.}, } @article {pmid28990487, year = {2018}, author = {Takeuchi, K}, title = {GABA, A Primary Metabolite Controlled by the Gac/Rsm Regulatory Pathway, Favors a Planktonic Over a Biofilm Lifestyle in Pseudomonas protegens CHA0.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {31}, number = {2}, pages = {274-282}, doi = {10.1094/MPMI-05-17-0120-R}, pmid = {28990487}, issn = {0894-0282}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cucumis ; Gene Expression Regulation, Bacterial/*physiology ; Guanosine Tetraphosphate ; Mutation ; Pseudomonas/*physiology ; Signal Transduction ; }, abstract = {In Pseudomonas protegens CHA0 and other fluorescent pseudomonads, the Gac/Rsm signal transduction pathway is crucial for the expression of secondary metabolism and the biological control of fungi, nematodes, and insects. Based on the findings of a previous metabolomic study, the role of intracellular γ-aminobutyrate (GABA) as a potential signal in the Gac/Rsm pathway was investigated herein. The function and regulation of a gabDT (c01870-c01880) gene cluster in strain CHA0 were described. The gabT gene encoded GABA transaminase (GABAT) and enabled the growth of the bacterium on GABA, whereas the upstream gabD gene (annotated as a gene encoding succinic semialdehyde dehydrogenase) had an unknown function. A gacA mutant exhibited low GABAT activity, leading to the markedly greater intracellular accumulation of GABA than in the wild type. In the gacA mutant, the RsmA and RsmE proteins caused translational gabD repression, with concomitant gabT repression. Due to very low GABAT activity, the gabT mutant accumulated GABA to high levels. This trait promoted a planktonic lifestyle, reduced biofilm formation, and favored root colonization without exhibiting the highly pleiotropic gacA phenotypes. These results suggest an important role of GABA in the Gac/Rsm-regulated niche adaptation of strain CHA0 to plant roots.}, } @article {pmid28990144, year = {2018}, author = {Carvalho, ML and Pinto, AP and Raniero, LJ and Costa, MS}, title = {Biofilm formation by Candida albicans is inhibited by photodynamic antimicrobial chemotherapy (PACT), using chlorin e6: increase in both ROS production and membrane permeability.}, journal = {Lasers in medical science}, volume = {33}, number = {3}, pages = {647-653}, pmid = {28990144}, issn = {1435-604X}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/drug effects/*growth & development/radiation effects ; Candida albicans/drug effects/*physiology ; Cell Membrane Permeability/*drug effects/*radiation effects ; Chlorophyllides ; Microbial Sensitivity Tests ; Photosensitizing Agents/*pharmacology ; Porphyrins/*pharmacology ; Reactive Oxygen Species/*metabolism ; }, abstract = {Candida albicans is an opportunistic fungal producing both superficial and systemic infections in immunocompromised patients. Furthermore, it has been described an increase in the frequency of infections which have become refractory to standard antifungal therapy. Photodynamic antimicrobial chemotherapy (PACT) is a potential antimicrobial therapy that combines visible light and a nontoxic dye, known as a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells. The objective of this study was to investigate the effects of PACT, using chlorin e6, as a photosensitizer on C. albicans. In this work, we studied the effect of PACT on both cell growth and biofilm formation by C. albicans. In addition, both ROS production and cell permeability were determined after PACT. PACT inhibited both growth and biofilm formation by C. albicans. We have also observed that PACT increased both ROS production (six times) and cell membrane permeability (five times) in C. albicans. PACT decreased both cell growth and biofilm development. The effect of PACT using chlorin e6 on C. albicans could be associated with an increase in ROS production, which could increase cell permeability, producing permanent damage to the cell membranes, leading to the cell death.}, } @article {pmid28988900, year = {2018}, author = {Turan, H and Demirbilek, M}, title = {Biofilm-forming capacity of blood-borne Candida albicans strains and effects of antifungal agents.}, journal = {Revista Argentina de microbiologia}, volume = {50}, number = {1}, pages = {62-69}, doi = {10.1016/j.ram.2017.05.003}, pmid = {28988900}, issn = {0325-7541}, mesh = {Amphotericin B ; *Antifungal Agents/pharmacology ; *Biofilms ; Candida ; *Candida albicans ; Echinocandins ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Infections related to Candida albicans biofilms and subsequent antifungal resistance have become more common with the increased use of indwelling medical devices. Regimens for preventing fungal biofilm formation are needed, particularly in high-risk patients. In this study, we investigated the biofilm formation rate of multiple strains of Candida albicans (n=162 clinical isolates), their antifungal susceptibility patterns, and the efficacy of certain antifungals for preventing biofilm formation. Biofilm formation was graded using a modified Christensen's 96-well plate method. We further analyzed 30 randomly chosen intense biofilm-forming isolates using the XTT method. Minimum biofilm inhibition concentrations (MBIC) of caspofungin, micafungin, anidulafungin, fluconazole, voriconazole, posaconazole, itraconazole, and amphotericin B were determined using the modified Calgary biofilm method. In addition, the inhibitory effects of antifungal agents on biofilm formation were investigated. Our study showed weak, moderate, and extensive biofilm formation in 29% (n=47), 38% (n=61), and 23% (n=37) of the isolates, respectively. We found that echinocandins had the lowest MBIC values and that itraconazole inhibited biofilm formation in more isolates (26/32; 81.3%) than other tested agents. In conclusion, echinocandins were most effective against formed biofilms, while itraconazole was most effective for preventing biofilm formation. Standardized methods are needed for biofilm antifungal sensitivity tests when determining the treatment and prophylaxis of C. albicans infections.}, } @article {pmid28988525, year = {2018}, author = {Tascini, C and Sozio, E and Corte, L and Sbrana, F and Scarparo, C and Ripoli, A and Bertolino, G and Merelli, M and Tagliaferri, E and Corcione, A and Bassetti, M and Cardinali, G and Menichetti, F}, title = {The role of biofilm forming on mortality in patients with candidemia: a study derived from real world data.}, journal = {Infectious diseases (London, England)}, volume = {50}, number = {3}, pages = {214-219}, doi = {10.1080/23744235.2017.1384956}, pmid = {28988525}, issn = {2374-4243}, mesh = {Aged ; Aged, 80 and over ; Antifungal Agents/therapeutic use ; Bayes Theorem ; Biofilms/*growth & development ; Candida/isolation & purification/*physiology ; Candidemia/diagnosis/drug therapy/*microbiology/*mortality ; Female ; Hospitals, University ; Humans ; Italy ; Male ; Middle Aged ; Predictive Value of Tests ; Retrospective Studies ; Risk Factors ; }, abstract = {BACKGROUND: Evaluation of the role on patient mortality exerted by biofilm forming (BF) Candida strains, by using predictive clinical data.

METHODS: Eighty-nine strains isolated from Candida bloodstream infection, occurring in two Italian University Hospitals, were employed in this study. A random forest (RF) model was built with a procedure of iterative selection of the risk factors potentially able to predict the probability of death. The similarity between patient conditions and Bayesian clustering was calculated in order to evaluate the role of predictors in the stratification of the death risk.

RESULTS: Three different groups of patients with different probability of death were obtained with a RF approach: Group 1 (mortality in 33.3% of cases), Group 2 (death in 50% of cases), and Group 3 (mortality in 76.9% of cases). The comparison between these three groups showed that BF correlated well with increased mortality in patients, admitted for medical diagnosis, with high APACHE II score and treated with azoles. Early treatment within 24 h between candidemia diagnosis and the beginning of antifungal therapy was associated with the lowest of BF rate and mortality.

CONCLUSIONS: BF by Candida spp. seems to be clinically associated with increased mortality especially in medical patients with higher Apache II score or treated with azoles.}, } @article {pmid28987620, year = {2017}, author = {Tan, Y and Leonhard, M and Schneider-Stickler, B}, title = {Evaluation of culture conditions for mixed biofilm formation with clinically isolated non-albicans Candida species and Staphylococcus epidermidis on silicone.}, journal = {Microbial pathogenesis}, volume = {112}, number = {}, pages = {215-220}, doi = {10.1016/j.micpath.2017.10.002}, pmid = {28987620}, issn = {1096-1208}, mesh = {Batch Cell Culture Techniques ; Biofilms/*growth & development ; Candida/growth & development/isolation & purification/*metabolism ; Cell Adhesion ; Culture Media/*chemistry ; Humans ; Silicones ; Staphylococcus epidermidis/growth & development/*metabolism ; Time Factors ; }, abstract = {Silicone is frequently used in clinical and medical fields for medical devices. Mixed biofilms composed of Candida and bacterial species causes frequently failure of medical silicone devices, In this in vitro study, we analyzed mixed biofilm formation of clinically isolated non-albicans Candida species and Staphylococcus epidermidis, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, BHI and TSB) and several culture variables (incubation period, feeding conditions and FBS). Our results showed that culture conditions strongly influence mixed biofilm formation. TSB and BHI resulted in larger amount of biofilm formations with stronger metabolic activity of biofilms. Growth conditions may also influence the biofilm formation, which was enhanced by longer incubation period, using a fed-batch system and FBS. Therefore, the potential influences of external environmental factors are very important for mixed biofilm formation with clinically isolated non-albicans Candida species and S. epidermidis, which should be considered when designing or studying the mixed biofilm under in vitro conditions.}, } @article {pmid28986371, year = {2017}, author = {Schiebel, J and Böhm, A and Nitschke, J and Burdukiewicz, M and Weinreich, J and Ali, A and Roggenbuck, D and Rödiger, S and Schierack, P}, title = {Genotypic and Phenotypic Characteristics Associated with Biofilm Formation by Human Clinical Escherichia coli Isolates of Different Pathotypes.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {24}, pages = {}, pmid = {28986371}, issn = {1098-5336}, mesh = {*Biofilms ; Escherichia coli/genetics/*physiology ; Escherichia coli Infections/*microbiology/physiopathology ; *Genotype ; Humans ; *Phenotype ; }, abstract = {Bacterial biofilm formation is a widespread phenomenon and a complex process requiring a set of genes facilitating the initial adhesion, maturation, and production of the extracellular polymeric matrix and subsequent dispersal of bacteria. Most studies on Escherichia coli biofilm formation have investigated nonpathogenic E. coli K-12 strains. Due to the extensive focus on laboratory strains in most studies, there is poor information regarding biofilm formation by pathogenic E. coli isolates. In this study, we genotypically and phenotypically characterized 187 human clinical E. coli isolates representing various pathotypes (e.g., uropathogenic, enteropathogenic, and enteroaggregative E. coli). We investigated the presence of biofilm-associated genes ("genotype") and phenotypically analyzed the isolates for motility and curli and cellulose production ("phenotype"). We developed a new screening method to examine the in vitro biofilm formation ability. In summary, we found a high prevalence of biofilm-associated genes. However, we could not detect a biofilm-associated gene or specific phenotype correlating with the biofilm formation ability. In contrast, we did identify an association of increased biofilm formation with a specific E. coli pathotype. Enteroaggregative E. coli (EAEC) was found to exhibit the highest capacity for biofilm formation. Using our image-based technology for the screening of biofilm formation, we demonstrated the characteristic biofilm formation pattern of EAEC, consisting of thick bacterial aggregates. In summary, our results highlight the fact that biofilm-promoting factors shown to be critical for biofilm formation in nonpathogenic strains do not reflect their impact in clinical isolates and that the ability of biofilm formation is a defined characteristic of EAEC.IMPORTANCE Bacterial biofilms are ubiquitous and consist of sessile bacterial cells surrounded by a self-produced extracellular polymeric matrix. They cause chronic and device-related infections due to their high resistance to antibiotics and the host immune system. In nonpathogenic Escherichia coli, cell surface components playing a pivotal role in biofilm formation are well known. In contrast, there is poor information for their role in biofilm formation of pathogenic isolates. Our study provides insights into the correlation of biofilm-associated genes or specific phenotypes with the biofilm formation ability of commensal and pathogenic E. coli Additionally, we describe a newly developed method enabling qualitative biofilm analysis by automated image analysis, which is beneficial for high-throughput screenings. Our results help to establish a better understanding of E. coli biofilm formation.}, } @article {pmid28983655, year = {2017}, author = {Chatterjee, M and D'Morris, S and Paul, V and Warrier, S and Vasudevan, AK and Vanuopadath, M and Nair, SS and Paul-Prasanth, B and Mohan, CG and Biswas, R}, title = {Mechanistic understanding of Phenyllactic acid mediated inhibition of quorum sensing and biofilm development in Pseudomonas aeruginosa.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {22}, pages = {8223-8236}, doi = {10.1007/s00253-017-8546-4}, pmid = {28983655}, issn = {1432-0614}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheters/microbiology ; Computer Simulation ; Disease Models, Animal ; Gene Expression ; Genetic Complementation Test ; Lactates/*pharmacology ; Lactobacillus/metabolism ; Oryzias/microbiology ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/pathogenicity ; Pyocyanine/metabolism ; Quorum Sensing/*drug effects ; Virulence Factors ; }, abstract = {Pseudomonas aeruginosa depends on its quorum sensing (QS) system for its virulence factors' production and biofilm formation. Biofilms of P. aeruginosa on the surface of indwelling catheters are often resistant to antibiotic therapy. Alternative approaches that employ QS inhibitors alone or in combination with antibiotics are being developed to tackle P. aeruginosa infections. Here, we have studied the mechanism of action of 3-Phenyllactic acid (PLA), a QS inhibitory compound produced by Lactobacillus species, against P. aeruginosa PAO1. Our study revealed that PLA inhibited the expression of virulence factors such as pyocyanin, protease, and rhamnolipids that are involved in the biofilm formation of P. aeruginosa PAO1. Swarming motility, another important criterion for biofilm formation of P. aeruginosa PAO1, was also inhibited by PLA. Gene expression, mass spectrometric, functional complementation assays, and in silico data indicated that the quorum quenching and biofilm inhibitory activities of PLA are attributed to its ability to interact with P. aeruginosa QS receptors. PLA antagonistically binds to QS receptors RhlR and PqsR with a higher affinity than its cognate ligands N-butyryl-L-homoserine lactone (C4-HSL) and 2-heptyl-3,4-dihydroxyquinoline (PQS; Pseudomonas quinolone signal). Using an in vivo intraperitoneal catheter-associated medaka fish infection model, we proved that PLA inhibited the initial attachment of P. aeruginosa PAO1 on implanted catheter tubes. Our in vitro and in vivo results revealed the potential of PLA as anti-biofilm compound against P. aeruginosa.}, } @article {pmid28983302, year = {2017}, author = {Cheng, P and Wang, Y and Liu, T and Liu, D}, title = {Biofilm Attached Cultivation of Chlorella pyrenoidosa Is a Developed System for Swine Wastewater Treatment and Lipid Production.}, journal = {Frontiers in plant science}, volume = {8}, number = {}, pages = {1594}, pmid = {28983302}, issn = {1664-462X}, abstract = {This study showed the new potential of using soluble contents and heavy metals in swine wastewater as nutrient supplements for the algae Chlorella pyrenoidosa with biofilm attached method. Algae with biofilm attached cultivation grew well in unpasteurized wastewater reaching a biomass productivity of 5.03 g m[-2] d[-1], lipid content of 35.9% and lipid productivity of 1.80 g m[-2] d[-1]. Chlorella grew in BG11 medium delivered lower values for each of the aforementioned parameters. The FAMEs compositions in the algae paste were mainly consisted of C16:0, C18:2, and C18:3. Algae removed NH4[+]-N, total phosphorus (TP), and COD by 75.9, 68.4, and 74.8%, respectively. Notably, Zn[2+], Cu[+], and Fe[2+] were removed from wastewater with a ratio of 65.71, 53.64, and 58.89%, respectively. Biofilm attached cultivation of C. pyrenoidosa in swine wastewater containing heavy metals could accumulate considerable biomass and lipid, and the removal ratio of NH4[+]-N, TP, COD, and as well as heavy metal were high. Treatment of wastewater with biofilm attached cultivation showed an increasingly popular for the concentration of microalgae and environmental sustainability.}, } @article {pmid28983293, year = {2017}, author = {Zeng, Z and Cai, X and Wang, P and Guo, Y and Liu, X and Li, B and Wang, X}, title = {Biofilm Formation and Heat Stress Induce Pyomelanin Production in Deep-Sea Pseudoalteromonas sp. SM9913.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1822}, pmid = {28983293}, issn = {1664-302X}, abstract = {Pseudoalteromonas is an important bacterial genus present in various marine habitats. Many strains of this genus are found to be surface colonizers on marine eukaryotes and produce a wide range of pigments. However, the exact physiological role and mechanism of pigmentation were less studied. Pseudoalteromonas sp. SM9913 (SM9913), an non-pigmented strain isolated from the deep-sea sediment, formed attached biofilm at the solid-liquid interface and pellicles at the liquid-air interface at a wide range of temperatures. Lower temperatures and lower nutrient levels promoted the formation of attached biofilm, while higher nutrient levels promoted pellicle formation of SM9913. Notably, after prolonged incubation at higher temperatures growing planktonically or at the later stage of the biofilm formation, we found that SM9913 released a brownish pigment. By comparing the protein profile at different temperatures followed by qRT-PCR, we found that the production of pigment at higher temperatures was due to the induction of melA gene which is responsible for the synthesis of homogentisic acid (HGA). The auto-oxidation of HGA can lead to the formation of pyomelanin, which has been shown in other bacteria. Fourier Transform Infrared Spectrometer analysis confirmed that the pigment produced in SM9913 was pyomelanin-like compound. Furthermore, we demonstrated that, during heat stress and during biofilm formation, the induction level of melA gene was significantly higher than that of the hmgA gene which is responsible for the degradation of HGA in the L-tyrosine catabolism pathway. Collectively, our results suggest that the production of pyomelanin of SM9913 at elevated temperatures or during biofilm formation might be one of the adaptive responses of marine bacteria to environmental cues.}, } @article {pmid28982089, year = {2018}, author = {Tang, B and Chen, Q and Bin, L and Huang, S and Zhang, W and Fu, F and Li, P}, title = {Insight into the microbial community and its succession of a coupling anaerobic-aerobic biofilm on semi-suspended bio-carriers.}, journal = {Bioresource technology}, volume = {247}, number = {}, pages = {591-598}, doi = {10.1016/j.biortech.2017.09.147}, pmid = {28982089}, issn = {1873-2976}, mesh = {Bacteria ; Biodiversity ; *Biofilms ; *Bioreactors ; }, abstract = {This work aims at establishing a coupling anaerobic-aerobic biofilm within a single bioreactor and revealing its microbial community and succession. By using a semi-suspended bio-carrier fabricated with 3D printing technique, an obvious DO gradient was gradually created within the biofilm, which demonstrated that a coupling anaerobic-aerobic biofilm was successfully established on the surface of bio-carriers. The results of metagenomic analysis revealed that the microbial community on the bio-carriers experienced a continuous succession in its structure and dominant species along with the operational time. The formed coupling biofilm created suitable micro multi-habitats for the co-existence of these microorganisms, including nitrifying and denitrifying bacteria, which were beneficial to the removing of organic pollutants and converting nutrients. Along with the succession, the microbial community was gradually dominated by several functional microorganisms. Overall, the results presented an approach to improve the microbial biodiversity by constructing a new structure and floating status of bio-carriers.}, } @article {pmid28981972, year = {2017}, author = {Waters, V and Ratjen, F}, title = {Standard versus biofilm antimicrobial susceptibility testing to guide antibiotic therapy in cystic fibrosis.}, journal = {The Cochrane database of systematic reviews}, volume = {10}, number = {10}, pages = {CD009528}, pmid = {28981972}, issn = {1469-493X}, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects/growth & development ; Cystic Fibrosis/*complications ; Female ; Humans ; Male ; Microbial Sensitivity Tests/methods ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects/physiology ; Randomized Controlled Trials as Topic ; Respiratory Tract Infections/*drug therapy/microbiology ; Sputum/microbiology ; }, abstract = {BACKGROUND: The antibiotics used to treat pulmonary infections in people with cystic fibrosis are typically chosen based on the results of antimicrobial susceptibility testing performed on bacteria traditionally grown in a planktonic mode (grown in a liquid). However, there is considerable evidence to suggest that Pseudomonas aeruginosa actually grows in a biofilm (or slime layer) in the airways of people with cystic fibrosis with chronic pulmonary infections. Therefore, choosing antibiotics based on biofilm rather than conventional antimicrobial susceptibility testing could potentially improve response to treatment of Pseudomonas aeruginosa in people with cystic fibrosis. This is an update of a previously published Cochrane Review.

OBJECTIVES: To compare biofilm antimicrobial susceptibility testing-driven therapy to conventional antimicrobial susceptibility testing-driven therapy in the treatment of Pseudomonas aeruginosa infection in people with cystic fibrosis.

SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Most recent search: 19 June 2017.We also searched two ongoing trials registries and the reference lists of relevant articles and reviews. Most recent searches: 24 August 2017 and 05 September 2017.

SELECTION CRITERIA: Randomized controlled trials of antibiotic therapy based on biofilm antimicrobial susceptibility testing compared to antibiotic therapy based on conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infection in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS: Both authors independently selected trials, assessed their risk of bias and extracted data from eligible trials. Additionally, the review authors contacted the trial investigators to obtain further information. The quality of the evidence was assessed using the GRADE criteria.

MAIN RESULTS: The searches identified two multicentre, randomized, double-blind controlled clinical trials eligible for inclusion in the review with a total of 78 participants (adults and children); one trial was done in people who were clinically stable, the other in people experiencing pulmonary exacerbations. These trials prospectively assessed whether the use of biofilm antimicrobial susceptibility testing improved microbiological and clinical outcomes in participants with cystic fibrosis who were infected with Pseudomonas aeruginosa. The primary outcome was the change in sputum Pseudomonas aeruginosa density from the beginning to the end of antibiotic therapy.Although the intervention was shown to be safe, the data from these two trials did not provide evidence that biofilm susceptibility testing was superior to conventional susceptibility testing either in terms of microbiological or lung function outcomes. One of the trials also measured risk and time to subsequent exacerbation as well as quality of life measures and did not demonstrate any difference between groups in these outcomes. Both trials had an overall low risk of bias and the quality of the evidence using GRADE criteria was deemed to be moderate to high for the outcomes selected.

AUTHORS' CONCLUSIONS: The current evidence is insufficient to recommend choosing antibiotics based on biofilm antimicrobial susceptibility testing rather than conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infections in people with cystic fibrosis. Biofilm antimicrobial susceptibility testing may be more appropriate in the development of newer, more effective formulations of drugs which can then be tested in clinical trials.}, } @article {pmid28980415, year = {2017}, author = {Lee, JH and Kim, YG and Lee, J}, title = {Carvacrol-rich oregano oil and thymol-rich thyme red oil inhibit biofilm formation and the virulence of uropathogenic Escherichia coli.}, journal = {Journal of applied microbiology}, volume = {123}, number = {6}, pages = {1420-1428}, doi = {10.1111/jam.13602}, pmid = {28980415}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cymenes ; Escherichia coli Infections/microbiology ; Humans ; Monoterpenes/*pharmacology ; Oils, Volatile/*pharmacology ; Origanum/*chemistry ; Plant Oils/*pharmacology ; Thymol/*pharmacology ; Thymus Plant/*chemistry ; Uropathogenic Escherichia coli/*drug effects/pathogenicity/physiology ; Virulence/drug effects ; }, abstract = {AIMS: Urinary tract infections are caused primarily by uropathogenic Escherichia coli (UPEC), and indwelling catheters are usually colonized by UPEC biofilms tolerant to common antibiotics. Hence, UPEC biofilms pose a substantial challenge, and there is an urgent need for effective control strategies.

METHODS AND RESULTS: In this study, 79 essential oils were screened for antibiofilm ability against UPEC. Components of active oils were identified, and their antibiofilm activities were also investigated using 96-well plates with crystal violet assay, scanning electron microscopy, and confocal laser scanning microscopy. Oregano oil and thyme red oil and their major common constituents, carvacrol and thymol, significantly inhibited UPEC biofilm formation at subinhibitory concentrations (<0·01%). These findings were supported by observations that carvacrol and thymol reduced fimbriae production and the swarming motility of UPEC. Furthermore, carvacrol and thymol markedly decreased the hemagglutinating ability of UPEC, and UPEC was more easily killed by human whole blood in the presence of carvacrol and thymol.

CONCLUSIONS: Carvacrol-rich oregano oil and thymol-rich thyme red oil have high antibiofilm and antivirulence activities against UPEC.

In the wake of rising antimicrobial resistance, we envisage that carvacrol and thymol could be used to prevent biofilm formation by UPEC and to reduce its virulence.}, } @article {pmid28978929, year = {2017}, author = {Ren, Z and Gao, H and Elser, JJ and Zhao, Q}, title = {Microbial functional genes elucidate environmental drivers of biofilm metabolism in glacier-fed streams.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {12668}, pmid = {28978929}, issn = {2045-2322}, mesh = {Biodiversity ; Biofilms/growth & development ; Climate Change ; *Ecosystem ; Genes, Bacterial/*genetics ; Hydrogen-Ion Concentration ; Metagenome/*genetics ; Nitrogen/metabolism ; RNA, Ribosomal, 16S/*genetics ; Sulfur/metabolism ; }, abstract = {Benthic biofilms in glacier-fed streams harbor diverse microorganisms driving biogeochemical cycles and, consequently, influencing ecosystem-level processes. Benthic biofilms are vulnerable to glacial retreat induced by climate change. To investigate microbial functions of benthic biofilms in glacier-fed streams, we predicted metagenomes from 16s rRNA gene sequence data using PICRUSt and identified functional genes associated with nitrogen and sulfur metabolisms based on KEGG database and explored the relationships between metabolic pathways and abiotic factors in glacier-fed streams in the Tianshan Mountains in Central Asia. Results showed that the distribution of functional genes was mainly associated with glacier area proportion, glacier source proportion, total nitrogen, dissolved organic carbon, and pH. For nitrogen metabolism, the relative abundance of functional genes associated with dissimilatory pathways was higher than those for assimilatory pathways. The relative abundance of functional genes associated with assimilatory sulfate reduction was higher than those involved with the sulfur oxidation system and dissimilatory sulfate reduction. Hydrological factors had more significant correlations with nitrogen metabolism than physicochemical factors and anammox was the most sensitive nitrogen cycling pathway responding to variation of the abiotic environment in these glacial-fed streams. In contrast, sulfur metabolism pathways were not sensitive to variations of abiotic factors in these systems.}, } @article {pmid28976842, year = {2018}, author = {Wongpraparatana, I and Matangkasombut, O and Thanyasrisung, P and Panich, M}, title = {Effect of Vital Tooth Bleaching on Surface Roughness and Streptococcal Biofilm Formation on Direct Tooth-Colored Restorative Materials.}, journal = {Operative dentistry}, volume = {43}, number = {1}, pages = {51-59}, doi = {10.2341/16-366-L}, pmid = {28976842}, issn = {1559-2863}, mesh = {Biofilms/*growth & development ; Carbamide Peroxide ; Composite Resins/therapeutic use ; Dental Restoration, Permanent/*adverse effects/methods ; Glass Ionomer Cements/therapeutic use ; Hydrogen Peroxide/adverse effects/therapeutic use ; In Vitro Techniques ; Peroxides/administration & dosage/therapeutic use ; Streptococcus mutans/*growth & development ; Streptococcus sanguis/*growth & development ; Surface Properties ; *Tooth Bleaching/adverse effects/methods ; Tooth Bleaching Agents/administration & dosage/therapeutic use ; Urea/administration & dosage/analogs & derivatives/therapeutic use ; }, abstract = {OBJECTIVE: To compare the effect of simulated bleaching with a 10% carbamide peroxide (CP) or a 40% hydrogen peroxide (HP) system on surface roughness of resin composite and resin-modified glass ionomer cement (RMGI) and streptococcal biofilm formation on these surfaces.

METHODS AND MATERIALS: Specimens of nanofilled resin composite and RMGI (n=108 each) were randomly divided into three groups (n=36 each): no treatment control, 10% CP, and 40% HP. The surface roughness values (Ra) were measured before and after treatments. The specimens in each group were randomly divided into three subgroups (n=12) and incubated with Streptococcus mutans, Streptococcus sanguinis, and trypticase soy broth control for 24 hours. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by scanning electron microscopy. The differences between the mean changes in Ra between the 10% CP and 40% HP groups of each material were evaluated with an independent t-test. The quantity of biofilm formation on each material was analyzed with one-way analysis of variance with the post hoc Tukey test (α=0.05).

RESULTS: Surface roughness significantly increased after bleaching in all groups. There was no significant difference between the 10% CP and 40% HP groups of each material. For S. mutans biofilm formation, bleaching with 10% CP and 40% HP increased biofilm on both materials compared to controls. However, S. sanguinis biofilm formation was significantly higher on bleached resin composite but not on RMGI specimens.

CONCLUSIONS: Simulated bleaching with 10% CP or 40% HP increased both surface roughness and biofilm formation on resin composite and RMGI, except for S. sanguinis biofilm on RMGI.}, } @article {pmid28974618, year = {2017}, author = {Mayer, FL and Kronstad, JW}, title = {Disarming Fungal Pathogens: Bacillus safensis Inhibits Virulence Factor Production and Biofilm Formation by Cryptococcus neoformans and Candida albicans.}, journal = {mBio}, volume = {8}, number = {5}, pages = {}, pmid = {28974618}, issn = {2150-7511}, support = {R01 AI100272/AI/NIAID NIH HHS/United States ; MOP-13234//CIHR/Canada ; }, mesh = {*Antibiosis ; Bacillus/enzymology/genetics/*physiology ; Biofilms/*growth & development ; Cell Wall/chemistry ; Chitinases/metabolism ; Cryptococcus neoformans/growth & development/*pathogenicity ; Humans ; Melanins/biosynthesis ; Microbial Interactions ; Virulence Factors/*biosynthesis ; }, abstract = {Bacteria interact with each other in nature and often compete for limited nutrient and space resources. However, it is largely unknown whether and how bacteria also interact with human fungal pathogens naturally found in the environment. Here, we identified a soil bacterium, Bacillus safensis, which potently blocked several key Cryptococcus neoformans virulence factors, including formation of the antioxidant pigment melanin and production of the antiphagocytic polysaccharide capsule. The bacterium also inhibited de novo cryptococcal biofilm formation but had only modest inhibitory effects on already formed biofilms or planktonic cell growth. The inhibition of fungal melanization was dependent on direct cell contact and live bacteria. B. safensis also had anti-virulence factor activity against another major human-associated fungal pathogen, Candida albicans Specifically, dual-species interaction studies revealed that the bacterium strongly inhibited C. albicans filamentation and biofilm formation. In particular, B. safensis physically attached to and degraded candidal filaments. Through genetic and phenotypic analyses, we demonstrated that bacterial chitinase activity against fungal cell wall chitin is a factor contributing to the antipathogen effect of B. safensisIMPORTANCE Pathogenic fungi are estimated to contribute to as many human deaths as tuberculosis or malaria. Two of the most common fungal pathogens, Cryptococcus neoformans and Candida albicans, account for up to 1.4 million infections per year with very high mortality rates. Few antifungal drugs are available for treatment, and development of novel therapies is complicated by the need for pathogen-specific targets. Therefore, there is an urgent need to identify novel drug targets and new drugs. Pathogens use virulence factors during infection, and it has recently been proposed that targeting these factors instead of the pathogen itself may represent a new approach to develop antimicrobials. Here, we identified a soil bacterium that specifically blocked virulence factor production and biofilm formation by C. neoformans and C. albicans We demonstrate that the bacterial antipathogen mechanism is based in part on targeting the fungal cell wall, a structure not found in human cells.}, } @article {pmid28974445, year = {2018}, author = {Silva, AF and Dos Santos, AR and Coelho Trevisan, DA and Ribeiro, AB and Zanetti Campanerut-Sá, PA and Kukolj, C and de Souza, EM and Cardoso, RF and Estivalet Svidzinski, TI and de Abreu Filho, BA and Junior, MM and Graton Mikcha, JM}, title = {Cinnamaldehyde induces changes in the protein profile of Salmonella Typhimurium biofilm.}, journal = {Research in microbiology}, volume = {169}, number = {1}, pages = {33-43}, doi = {10.1016/j.resmic.2017.09.007}, pmid = {28974445}, issn = {1769-7123}, mesh = {Acrolein/*analogs & derivatives/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Proteomics ; Salmonella typhimurium/*drug effects/genetics/metabolism ; }, abstract = {The effect of cinnamaldehyde against biofilm cells of Salmonella Typhimurium ATCC 14028 was evaluated. We also assessed differential protein patterns that were expressed by biofilms compared with planktonic cells and protein expression by cinnamaldehyde-treated biofilms cells. This compound decreased biofilm biomass and metabolic activity of biofilms at both concentrations tested. Cinnamaldehyde treatment reduced the number of attached cells in polypropylene, reflected by colony count and scanning electron microscopy. The proteomic analysis of biofilms compared with planktonic cells indicated that several proteins were upregulated or downregulated, especially proteins that are involved in energy metabolism. Peroxiredoxin, ATP synthase alpha chain protein, conjugal transfer nickase/helicase TraI and elongation factor G were upregulated in untreated-biofilm cells, and their expression decreased as a function of cinnamaldehyde treatment. Cinnamaldehyde had antibiofilm activity, and several differentially expressed proteins identified provide potential and interesting targets to explore new control strategies for S. Typhimurium biofilms.}, } @article {pmid28973965, year = {2017}, author = {Eberly, AR and Floyd, KA and Beebout, CJ and Colling, SJ and Fitzgerald, MJ and Stratton, CW and Schmitz, JE and Hadjifrangiskou, M}, title = {Biofilm Formation by Uropathogenic Escherichia coli Is Favored under Oxygen Conditions That Mimic the Bladder Environment.}, journal = {International journal of molecular sciences}, volume = {18}, number = {10}, pages = {}, pmid = {28973965}, issn = {1422-0067}, support = {T32 GM007347/GM/NIGMS NIH HHS/United States ; U24 DK076169/DK/NIDDK NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Escherichia coli Infections/*metabolism/microbiology/urine ; Humans ; Hypoxia/metabolism/microbiology/urine ; Oxygen/*metabolism/urine ; Urinary Bladder/*microbiology ; Urinary Tract Infections/*metabolism/microbiology/urine ; Uropathogenic Escherichia coli/*physiology ; }, abstract = {One of the most common urologic problems afflicting millions of people worldwide is urinary tract infection (UTI). The severity of UTIs ranges from asymptomatic bacteriuria to acute cystitis, and in severe cases, pyelonephritis and urosepsis. The primary cause of UTIs is uropathogenic Escherichia coli (UPEC), for which current antibiotic therapies often fail. UPEC forms multicellular communities known as biofilms on urinary catheters, as well as on and within bladder epithelial cells. Biofilm formation protects UPEC from environmental conditions, antimicrobial therapy, and the host immune system. Previous studies have investigated UPEC biofilm formation in aerobic conditions (21% oxygen); however, urine oxygen tension is reduced (4-6%), and urine contains molecules that can be used by UPEC as alternative terminal electron acceptors (ATEAs) for respiration. This study was designed to determine whether these different terminal electron acceptors utilized by E. coli influence biofilm formation. A panel of 50 urine-associated E. coli isolates was tested for the ability to form biofilm under anaerobic conditions and in the presence of ATEAs. Biofilm production was reduced under all tested sub-atmospheric levels of oxygen, with the notable exception of 4% oxygen, the reported concentration of oxygen within the bladder.}, } @article {pmid28972168, year = {2017}, author = {Marmont, LS and Whitfield, GB and Rich, JD and Yip, P and Giesbrecht, LB and Stremick, CA and Whitney, JC and Parsek, MR and Harrison, JJ and Howell, PL}, title = {PelA and PelB proteins form a modification and secretion complex essential for Pel polysaccharide-dependent biofilm formation in Pseudomonas aeruginosa.}, journal = {The Journal of biological chemistry}, volume = {292}, number = {47}, pages = {19411-19422}, pmid = {28972168}, issn = {1083-351X}, support = {R01 AI077628/AI/NIAID NIH HHS/United States ; 43998//Canadian Institutes of Health Research/International ; }, mesh = {Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Extracellular Matrix/metabolism ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Microbial Viability ; Periplasm/*metabolism ; Polysaccharides, Bacterial/*metabolism ; Protein Conformation ; Pseudomonas aeruginosa/genetics/growth & development/*metabolism ; }, abstract = {The pellicle (PEL) polysaccharide is synthesized by the opportunistic pathogen Pseudomonas aeruginosa and is an important biofilm constituent critical for bacterial virulence and persistence. PEL is a cationic polymer that promotes cell-cell interactions within the biofilm matrix through electrostatic interactions with extracellular DNA. Translocation of PEL across the outer membrane is proposed to occur via PelB, a membrane-embedded porin with a large periplasmic domain predicted to contain 19 tetratricopeptide repeats (TPRs). TPR-containing domains are typically involved in protein-protein interactions, and we therefore sought to determine whether PelB serves as a periplasmic scaffold that recruits other components of the PEL secretion apparatus. In this study, we show that the TPR domain of PelB interacts with PelA, an enzyme with PEL deacetylase and hydrolase activities. Structure determination of PelB TPRs 8-11 enabled us to design systematic deletions of individual TPRs and revealed that repeats 9-14, which are required for the cellular localization of PelA with PelB are also essential for PEL-dependent biofilm formation. Copurification experiments indicated that the interaction between PelA and PelB is direct and that the deacetylase activity of PelA increases and its hydrolase activity decreases when these proteins interact. Combined, our results indicate that the TPR-containing domain of PelB localizes PelA to the PEL secretion apparatus within the periplasm and that this may allow for efficient deacetylation of PEL before its export from the cell.}, } @article {pmid28971316, year = {2018}, author = {Kolouchová, I and Maťátková, O and Paldrychová, M and Kodeš, Z and Kvasničková, E and Sigler, K and Čejková, A and Šmidrkal, J and Demnerová, K and Masák, J}, title = {Resveratrol, pterostilbene, and baicalein: plant-derived anti-biofilm agents.}, journal = {Folia microbiologica}, volume = {63}, number = {3}, pages = {261-272}, pmid = {28971316}, issn = {1874-9356}, support = {17-15936S//Czech Science Foundation (GA CR)/ ; CZ.2.16/3.1.00/24503//Operational Programme Prague - Competitiveness/ ; NPU I (LO1601 - No.: MSMT-43760/2015)//National Program of Sustainability I/ ; }, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/growth & development ; Escherichia coli/drug effects/growth & development ; Flavanones/*pharmacology ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects/growth & development ; Resveratrol ; Staphylococcus epidermidis/drug effects/growth & development ; Stilbenes/*pharmacology ; }, abstract = {Microbial adhesion to surfaces and the subsequent biofilm formation may result in contamination in food industry and in healthcare-associated infections and may significantly affect postoperative care. Some plants produce substances with antioxidant and antimicrobial properties that are able to inhibit the growth of food-borne pathogens. The aim of our study was to evaluate antimicrobial and anti-biofilm effect of baicalein, resveratrol, and pterostilbene on Candida albicans, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. We determined the minimum inhibitory concentrations (MIC), the minimum adhesion inhibitory concentration (MAIC), and the minimum biofilm eradication concentration (MBEC) by crystal violet and XTT determination. Resveratrol and pterostilbene have been shown to inhibit the formation of biofilms as well as to disrupt preformed biofilms. Our results suggest that resveratrol and pterostilbene appear potentially very useful to control and inhibit biofilm contaminations by Candida albicans, Staphylococcus epidermidis, and Escherichia coli in the food industry.}, } @article {pmid28970943, year = {2017}, author = {Müsken, M and Klimmek, K and Sauer-Heilborn, A and Donnert, M and Sedlacek, L and Suerbaum, S and Häussler, S}, title = {Towards individualized diagnostics of biofilm-associated infections: a case study.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {22}, pmid = {28970943}, issn = {2055-5008}, abstract = {Organized within biofilm communities, bacteria exhibit resistance towards a broad spectrum of antibiotics. Thus, one might argue that bacteria isolated from biofilm-associated chronic infections should be subjected to resistance profiling under biofilm growth conditions. Various test systems have been developed to determine the biofilm-associated resistance; however, it is not clear to what extent the in vitro results reflect the situation in vivo, and whether the biofilm-resistance profile should guide clinicians in their treatment choice. To address this issue, we used confocal microscopy in combination with live/dead staining, and profiled biofilm-associated resistance of a large number (>130) of clinical Pseudomonas aeruginosa isolates from overall 15 cystic fibrosis patients. Our results demonstrate that in addition to a general non-responsiveness of bacteria when grown under biofilm conditions, there is an isolate-specific and antibiotic-specific biofilm-resistance profile. This individual resistance profile is independent on the structural properties of the biofilms. Furthermore, biofilm resistance is not linked to the resistance profile under planktonic growth conditions, or a mucoid, or small colony morphology of the tested isolates. Instead, it seems that individual biofilm structures evolve during biofilm-associated growth and are shaped by environment-specific cues. In conclusion, our results demonstrate that biofilm resistance profiles are isolate specific and cannot be deduced from commonly studied phenotypes. Further clinical studies will have to show the added value of biofilm-resistance profiling. Individualized diagnosis of biofilm resistance might lead to more rational recommendations for antimicrobial therapy and, thus, increased effectiveness of the treatment of chronically infected patients.}, } @article {pmid28970909, year = {2017}, author = {Perez-Soto, N and Moule, L and Crisan, DN and Insua, I and Taylor-Smith, LM and Voelz, K and Fernandez-Trillo, F and Krachler, AM}, title = {Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio cholerae and downregulate the expression of virulence genes.}, journal = {Chemical science}, volume = {8}, number = {8}, pages = {5291-5298}, pmid = {28970909}, issn = {2041-6520}, support = {//Wellcome Trust/United Kingdom ; }, abstract = {Here we report the first application of non-bactericidal synthetic polymers to modulate the physiology of a bacterial pathogen. Poly(N-[3-(dimethylamino)propyl] methacrylamide) (P1) and poly(N-(3-aminopropyl)methacrylamide) (P2), cationic polymers that bind to the surface of V. cholerae, the infectious agent causing cholera disease, can sequester the pathogen into clusters. Upon clustering, V. cholerae transitions to a sessile lifestyle, characterised by increased biofilm production and the repression of key virulence factors such as the cholera toxin (CTX). Moreover, clustering the pathogen results in the minimisation of adherence and toxicity to intestinal epithelial cells. Our results suggest that the reduction in toxicity is associated with the reduction to the number of free bacteria, but also the downregulation of toxin production. Finally we demonstrate that these polymers can reduce colonisation of zebrafish larvae upon ingestion of water contaminated with V. cholerae. Overall, our results suggest that the physiology of this pathogen can be modulated without the need to genetically manipulate the microorganism and that this modulation is an off-target effect that results from the intrinsic ability of the pathogen to sense and adapt to its environment. We believe these findings pave the way towards a better understanding of the interactions between pathogenic bacteria and polymeric materials and will underpin the development of novel antimicrobial polymers.}, } @article {pmid28970736, year = {2017}, author = {Kazakos, EI and Dorrell, N and Polyzos, SA and Deretzi, G and Kountouras, J}, title = {Comment on "Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics".}, journal = {World journal of gastroenterology}, volume = {23}, number = {33}, pages = {6194-6196}, pmid = {28970736}, issn = {2219-2840}, mesh = {*Anti-Bacterial Agents ; Biofilms/drug effects ; Drug Resistance, Microbial/drug effects ; Helicobacter pylori/*drug effects ; Humans ; beta-Defensins ; }, abstract = {Attaran et al[[1]] have recently shown that decreased susceptibility of established Helicobacter pylori (H. pylori) biofilms to specific antibiotics, was associated with the overtly enhanced transcription of two efflux pump genes, hp1165 and hefA, involved in specific resistance to tetracycline and multiple antibiotics, respectively. Apart from antibiotic exposure, secretion of multiple antimicrobial peptides, such as human β-defensins (hβDs), by the gastric epithelium upon Hp challenge, may act as early triggering events that positively impact biofilm formation and thus, antibiotic resistance. In this regard, we undertook genomic transcriptional studies using Hp 26695 strain following exposure to sublethal, similar to those present in the gastric niche, concentrations of hβDs in an attempt to provide preliminary data regarding possible mechanisms of immune evasion and selective sensitivity of Hp. Our preliminary results indicate that hβD exposure ignites a rapid response that is largely due to the activation of several, possibly interconnected transcriptional regulatory networks - origons - that ultimately coordinate cellular processes needed to maintain homeostasis and successful adaptation of the bacterium in the gastric environment. In addition, we have shown that both antibiotic and hβD resistance are mediated by dedicated periplasmic transporters, including the aforementioned efflux pump genes hp1165 and hefA, involved in active export of antibiotics from the cell membrane and/or, as recently suggested, substrate sensing and signalling. Furthermore, it appears that sublethal doses of hβDs may enhance biofilm formation by the sustained expression of, mainly, quorum sensing-related genes. In conclusion, we provide additional data regarding the role of specific innate immune molecules in antibiotic cross-resistance mechanisms that may deepen our understanding in the context of the development of novel eradication regimens.}, } @article {pmid28970274, year = {2017}, author = {Ferris, RA and McCue, PM and Borlee, GI and Glapa, KE and Martin, KH and Mangalea, MR and Hennet, ML and Wolfe, LM and Broeckling, CD and Borlee, BR}, title = {Model of Chronic Equine Endometritis Involving a Pseudomonas aeruginosa Biofilm.}, journal = {Infection and immunity}, volume = {85}, number = {12}, pages = {}, pmid = {28970274}, issn = {1098-5522}, mesh = {Animals ; Biofilms/*growth & development ; Endometritis/microbiology/*pathology ; Endometrium/microbiology/pathology ; Female ; Genes, Reporter ; Horse Diseases/microbiology/*pathology ; Horses ; Luciferases/analysis/genetics ; Pseudomonas Infections/microbiology/*pathology ; Pseudomonas aeruginosa/genetics/*physiology ; }, abstract = {Bacteria in a biofilm community have increased tolerance to antimicrobial therapy. To characterize the role of biofilms in equine endometritis, six mares were inoculated with lux-engineered Pseudomonas aeruginosa strains isolated from equine uterine infections. Following establishment of infection, the horses were euthanized and the endometrial surfaces were imaged for luminescence to localize adherent lux-labeled bacteria. Samples from the endometrium were collected for cytology, histopathology, carbohydrate analysis, and expression of inflammatory cytokine genes. Tissue-adherent bacteria were present in focal areas between endometrial folds (6/6 mares). The Pel exopolysaccharide (biofilm matrix component) and cyclic di-GMP (biofilm-regulatory molecule) were detected in 6/6 mares and 5/6 mares, respectively, from endometrial samples with tissue-adherent bacteria (P < 0.05). A greater incidence (P < 0.05) of Pel exopolysaccharide was present in samples fixed with Bouin's solution (18/18) than in buffered formalin (0/18), indicating that Bouin's solution is more appropriate for detecting bacteria adherent to the endometrium. There were no differences (P > 0.05) in the number of inflammatory cells in the endometrium between areas with and without tissue-adherent bacteria. Neutrophils were decreased (P < 0.05) in areas surrounding tissue-adherent bacteria compared to those in areas free of adherent bacteria. Gene expression of interleukin-10, an immune-modulatory cytokine, was significantly (P < 0.05) increased in areas of tissue-adherent bacteria compared to that in endometrium absent of biofilm. These findings indicate that P. aeruginosa produces a biofilm in the uterus and that the host immune response is modulated focally around areas with biofilm, but inflammation within the tissue is similar in areas with and without biofilm matrix. Future studies will focus on therapeutic options for elimination of bacterial biofilm in the equine uterus.}, } @article {pmid28969677, year = {2017}, author = {Jardak, M and Elloumi-Mseddi, J and Aifa, S and Mnif, S}, title = {Chemical composition, anti-biofilm activity and potential cytotoxic effect on cancer cells of Rosmarinus officinalis L. essential oil from Tunisia.}, journal = {Lipids in health and disease}, volume = {16}, number = {1}, pages = {190}, pmid = {28969677}, issn = {1476-511X}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Bicyclic Monoterpenes ; Biofilms/*drug effects/growth & development ; Bridged Bicyclo Compounds/isolation & purification ; Camphor/isolation & purification ; Cell Survival/drug effects ; Cyclohexane Monoterpenes ; Cyclohexanols/isolation & purification ; Eucalyptol ; Gas Chromatography-Mass Spectrometry ; HeLa Cells ; Humans ; MCF-7 Cells ; Microbial Sensitivity Tests ; Monoterpenes/isolation & purification ; Oils, Volatile/chemistry/isolation & purification/*pharmacology ; Plants, Medicinal ; Polycyclic Sesquiterpenes ; Rosmarinus/*chemistry ; Sesquiterpenes/isolation & purification ; Staphylococcus aureus/*drug effects/growth & development ; Staphylococcus epidermidis/*drug effects/growth & development ; Terpenes/isolation & purification ; Tunisia ; }, abstract = {BACKGROUND: Rosmarinus officinalis L. from Tunisia, popularly known as rosemary, is of a considerable importance for its medicinal uses and aromatic value. The aim of this study was to examine the chemical composition of Rosmarinus officinalis essential oil (ROEO) and to evaluate its antibiofilm activity on biofilm-forming bacterium and its anticancer activity on cancer cell lines.

METHODS: The chemical composition of Rosmarinus officinalis essential oil (ROEO) was analyzed by GC-MS and its antibacterial activity was evaluated by micro-dilution method. The antibofilm activity of ROEO was evaluated using the crystal violet test and the cytotoxicity activity was determined by the MTT assay.

RESULTS: In this research, thirty-six compounds were identified in ROEO using GC-MS analyses. The main components were 1,8-cineole (23.56%), camphene (12.78%), camphor (12.55%) and β-pinene (12.3%). The antibacterial activity of ROEO was evaluated by micro-dilution method. The oil exhibited inhibition and bactericidal effect against two strains: Staphylococcus aureus ATCC 9144 and Staphylococcus epidermidis S61. It was found that the minimum inhibitory concentration (MIC) obtained for S. aureus and S. epidermidis ranged from 1.25 to 2.5 and from 0.312 to 0.625 μl ml[-1], respectively and the minimum bactericidal concentration (MBC) were in the order of 5 and 2.5 μl ml[-1], respectively. Furthermore, this oil showed a S. epidermidis biofilm inhibition more than 57% at a concentration of 25 μl ml[-1]. The eradication of 67% of the established biofilm was observed at a concentration of 50 μl ml[-1] of ROEO, whereas the dose of 25 μl ml[-1] removed only 38% of preformed biofilm. ROEO strongly inhibited the proliferation of Hela and MCF-7 cells with IC50 values of 0.011 and 0.253 μl ml[-1], respectively.

CONCLUSION: Our results demonstrate that ROEO could have a potential role in the treatment of diseases related to infection by microorganisms or proliferation of cancer cells.}, } @article {pmid28968534, year = {2017}, author = {Sadiq, FA and Flint, S and Yuan, L and Li, Y and Liu, T and He, G}, title = {Propensity for biofilm formation by aerobic mesophilic and thermophilic spore forming bacteria isolated from Chinese milk powders.}, journal = {International journal of food microbiology}, volume = {262}, number = {}, pages = {89-98}, doi = {10.1016/j.ijfoodmicro.2017.09.015}, pmid = {28968534}, issn = {1879-3460}, mesh = {Animals ; Anoxybacillus/genetics/*isolation & purification ; Bacillus licheniformis/genetics/*isolation & purification ; Bacterial Load ; Biofilms/*growth & development ; China ; Geobacillus stearothermophilus/genetics/*isolation & purification ; Milk/*microbiology ; Random Amplified Polymorphic DNA Technique ; Spores, Bacterial/*growth & development ; Stainless Steel ; }, abstract = {Biofilms on the surface of dairy manufacturing plants are potential reservoirs of microbial contamination. These microbial aggregates may harbour pathogenic and spoilage organisms which contaminate dairy products. The biofilm forming capacity of many spore forming isolates of dairy origin has not been given much attention. The present study explored the biofilm forming potential of 148 isolates, comprising mesophilic and thermophilic bacteria, with particular emphasis on Bacillus licheniformis on polystyrene and stainless steel (SS) surfaces. We concluded that only four species are of significance for biofilm development on the surface of SS in the presence of skimmed milk, namely, B. licheniformis, Geobacillus stearothermophilus, Geobacillus thermoleovorans group and Anoxybacillus flavithermus. The maximum number of cells recovered from the biofilms developed on SS coupons in the presence of skimmed milk for these four species was as follows: 4.8, 5.2, 4.5 and 5.3logCFU/cm[2], respectively. Number of cells recovered from biofilms on 1cm[2] SS coupons increased in the presence of tryptic soy broth (TSB) for all mesophiles including B. licheniformis, while decreased for G. stearothermophilus, G. thermoleovorans group and A. flavithermus. The crystal violet staining assay on polystyrene proved to be inadequate to predict cell counts on SS for the bacteria tested in our trial in the presence of either TSB or skimmed milk. The results support the idea that biofilm formation is an important part of bacterial survival strategy as only the most prevalent isolates from milk powders formed good biofilms on SS in the presence of skimmed milk. Biofilm formation also proved to be a strain-dependent characteristic and interestingly significant variation in biofilm formation was observed within the same RAPD groups of B. licheniformis which supports the previously reported genetic and phenotypic heterogeneity within the same RAPD based groups. The work reported in this manuscript will broaden our knowledge on biofilm formation of a large number of dairy isolates and emphasize strain and substrate dependence.}, } @article {pmid28965300, year = {2017}, author = {Satish, L and Santhakumari, S and Gowrishankar, S and Pandian, SK and Ravi, AV and Ramesh, M}, title = {Rapid biosynthesized AgNPs from Gelidiella acerosa aqueous extract mitigates quorum sensing mediated biofilm formation of Vibrio species-an in vitro and in vivo approach.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {35}, pages = {27254-27268}, pmid = {28965300}, issn = {1614-7499}, support = {UGC order no. F.4-1/2006 (BSR)/7-326/2011(BSR)//University Grants Commission, New Delhi, Government of India/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Artemia/drug effects ; Biofilms/*drug effects ; Chromobacterium/drug effects ; Metal Nanoparticles/*chemistry ; Plant Extracts/pharmacology ; Quorum Sensing/drug effects ; Rhodophyta/*chemistry ; Silver/*pharmacology ; Vibrio/*drug effects/*physiology ; }, abstract = {The present study explores the non-bactericidal anti-virulence efficacy of green synthesized silver nanoparticles (AgNPs) from Gelidiella acerosa against multi-drug resistant Vibrio spp. Spectral characterization of AgNPs was performed through UV-Visible, FT-IR, and energy-dispersive spectroscopic techniques followed by X-ray crystallography and zeta potential analysis. Further, the structural characterization was done by electron and atomic force microscopic techniques. AgNPs profoundly quelled the quorum sensing mediated violacein production in Chromobacterium violaceum and CV026. Characterized AgNPs at 100 μg mL[-1] concentrations depicted a phenomenal anti-biofilm efficacy against Vibrio parahaemolyticus (71%) and Vibrio vulnificus (83%) biofilms, which was further confirmed through light, confocal, and scanning electron microscopic analyses. In vitro bioassays revealed the remarkable inhibitory values of AgNPs, by inhibiting the exopolysaccharide production, hydrophobicity, and motility. In vivo studies using Artemia franciscana larvae also confirmed the anti-infective proficiency, as the AgNPs effectively reduced the bacterial colonization and enhanced the survival rate of larvae up to 100% without any toxicity effect. Graphical abstract Rapid biosynthesized AgNPs from Gelidiella acerosa quench quorum sensing controlled virulence traits in vibrios.}, } @article {pmid28965241, year = {2018}, author = {An, SQ and Tang, JL}, title = {The Ax21 protein influences virulence and biofilm formation in Stenotrophomonas maltophilia.}, journal = {Archives of microbiology}, volume = {200}, number = {1}, pages = {183-187}, pmid = {28965241}, issn = {1432-072X}, support = {2014A002//Ba Gui Scholar Program of Guangxi Zhuang Autonomous Region of China/ ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cross Infection/*microbiology ; Gram-Negative Bacterial Infections/*microbiology ; Humans ; Stenotrophomonas maltophilia/genetics/isolation & purification/pathogenicity/*physiology ; Virulence ; }, abstract = {Stenotrophomonas maltophilia is an antibiotic-resistant Gram-negative pathogen, which is associated with hospital-acquired infection. The genome encodes a protein highly related to the Ax21 protein of Xanthomonas oryzae that is implicated in interactions of this plant pathogen with rice. Here, we report on the pleiotropic nature of ax21 mutation in S. maltophilia and the effects of addition of the Ax21 protein on the restoration of the wild-type phenotype. We show that loss by mutation of Ax21 leads to reduced motility, reduced biofilm formation, reduced tolerance to the antibiotic tobramycin and reduced virulence to larvae of Galleria mellonella, as well as alteration in the expression of specific genes associated with virulence or antibiotic resistance. Addition of the Ax21protein restored motility and the level of gene expression towards wild type. These findings are consistent with the notion that the Ax21 protein is involved in intraspecies communication, although other interpretations cannot be discounted.}, } @article {pmid28964986, year = {2017}, author = {Pires, DP and Melo, L and Vilas Boas, D and Sillankorva, S and Azeredo, J}, title = {Phage therapy as an alternative or complementary strategy to prevent and control biofilm-related infections.}, journal = {Current opinion in microbiology}, volume = {39}, number = {}, pages = {48-56}, doi = {10.1016/j.mib.2017.09.004}, pmid = {28964986}, issn = {1879-0364}, mesh = {Animals ; *Bacterial Infections/prevention & control/therapy ; *Biofilms ; Disease Models, Animal ; Humans ; Mice ; *Phage Therapy ; Swine ; *Wound Infection/prevention & control/therapy ; }, abstract = {The complex heterogeneous structure of biofilms confers to bacteria an important survival strategy. Biofilms are frequently involved in many chronic infections in consequence of their low susceptibility to antibiotics as well as resistance to host defences. The increasing need of novel and effective treatments to target these complex structures has led to a growing interest on bacteriophages (phages) as a strategy for biofilm control and prevention. Phages can be used alone, as a cocktail to broaden the spectra of activity, or in combination with other antimicrobials to improve their efficacy. Here, we summarize the studies involving the use of phages for the treatment or prevention of bacterial biofilms, highlighting the biofilm features that can be tackled with phages or combined therapy approaches.}, } @article {pmid28964839, year = {2018}, author = {Tiwari, V and Patel, V and Tiwari, M}, title = {In-silico screening and experimental validation reveal L-Adrenaline as anti-biofilm molecule against biofilm-associated protein (Bap) producing Acinetobacter baumannii.}, journal = {International journal of biological macromolecules}, volume = {107}, number = {Pt A}, pages = {1242-1252}, doi = {10.1016/j.ijbiomac.2017.09.105}, pmid = {28964839}, issn = {1879-0003}, mesh = {Acinetobacter baumannii/drug effects/pathogenicity ; Bacterial Proteins/*antagonists & inhibitors/chemistry ; Biofilms/*drug effects ; Carbapenems/*antagonists & inhibitors/chemistry ; Computer Simulation ; Epinephrine/analogs & derivatives/*chemistry/pharmacology ; Humans ; Molecular Dynamics Simulation ; }, abstract = {Acinetobacter baumannii, an ESKAPE pathogen, causes various nosocomial infections and has capacity to produce biofilm. Biofilm produced by this bacterium is highly tolerant to environmental factors and different antibiotics. Biofilm-associated protein (Bap) plays a significant role in the biofilm formation by A. baumannii and found in the extra cellular matrix of the biofilm. Therefore, it becomes essential to find a potential drug against Bap that has capacity to inhibit biofilm formation by A. baumannii. In-silico screening, molecular mechanics and molecular dynamics studies identified ZINC00039089 (L-Adrenaline) as an inhibitor for Bap of A. baumannii. Recently, it is reported that Bap can form amyloid like structure; hence we have created dimer of Bap protein. This inhibitor can bind to dimeric Bap with good affinity. It confirms that ZINC00039089 (L-Adrenaline) can bind with Bap monomer as well as oligomeric Bap, responsible for amyloid formation and biofilm formation. Hence, we have tested Adrenaline as an anti-biofilm molecule and determined its IC50 value against biofilm. The result showed Adrenaline has anti-biofilm activity with IC50 value of 75μg/ml. Therefore; our finding suggests that L-Adrenaline can be developed to inhibit biofilm formation by carbapenem resistant strain of Acinetobacter baumannii.}, } @article {pmid28964825, year = {2017}, author = {Miladi, H and Zmantar, T and Kouidhi, B and Al Qurashi, YMA and Bakhrouf, A and Chaabouni, Y and Mahdouani, K and Chaieb, K}, title = {Synergistic effect of eugenol, carvacrol, thymol, p-cymene and γ-terpinene on inhibition of drug resistance and biofilm formation of oral bacteria.}, journal = {Microbial pathogenesis}, volume = {112}, number = {}, pages = {156-163}, doi = {10.1016/j.micpath.2017.09.057}, pmid = {28964825}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents ; Bacteria/*drug effects ; Biofilms/*drug effects ; Cyclohexane Monoterpenes ; Cymenes ; Dental Caries/microbiology ; Dental Enamel/microbiology ; Drug Resistance, Bacterial/*drug effects ; Drug Synergism ; Ethidium/pharmacology ; Eugenol/*pharmacology ; Microbial Sensitivity Tests ; Microbiota/drug effects ; Microscopy, Electron, Scanning ; Monoterpenes/*pharmacology ; Mouth/*microbiology ; Oils, Volatile/pharmacology ; Staphylococcus aureus/cytology/drug effects ; Tetracycline/pharmacology ; Thymol/*pharmacology ; }, abstract = {Dental caries remains the most prevalent oral infectious disease worldwide. In this study, the antibacterial and the antibiofilm activities of five essential oils (EO's): eugenol (EUG), carvacrol (CAR), thymol (TYH), p-cymene (CYM) and γ-terpinene (TER) were tested (alone or in combinaison with tetracycline) against oral bacteria. In addition, their potential roles to enhance the accumulation of ethidium bromide (EtBr) in bacterial cells were tested. Our results indicated that EO's induced a selective antimicrobial activity. A synergistic effect of EO's and tetracycline (TET) was noticed with a reduction rate ranged from 2 to 8-fold. In addition, the efflux of EtBr was inhibited with a decrease in loss of EtBr from the bacteria. On the other hand a significant anti-biofilm activities of EO's (alone or combined with antibiotics) was noticed. In conclusion the tested EO's may be considered as a potential natural source with a resistance-modifying activity and may be applied to eradicate bacterial biofilm.}, } @article {pmid28963222, year = {2017}, author = {Shetty, D and Grigoryan, AA and Alshalchi, S and Withana Gamage, N and Roy, J and Lawrence, JR and Vidovic, S and Korber, DR}, title = {Draft Genome Sequences of Biofilm-Forming and Non-Biofilm-Forming Nontyphoidal Salmonella enterica Serovars.}, journal = {Genome announcements}, volume = {5}, number = {39}, pages = {}, pmid = {28963222}, issn = {2169-8287}, abstract = {The genetic basis for biofilm formation among nontyphoidal salmonellae (NTS) remains poorly understood. This draft genome submission provides initial insights on the genetic differences between biofilm-forming and non-biofilm-forming clinical and environmental NTS serovars.}, } @article {pmid28962915, year = {2017}, author = {Junka, AF and Żywicka, A and Szymczyk, P and Dziadas, M and Bartoszewicz, M and Fijałkowski, K}, title = {A.D.A.M. test (Antibiofilm Dressing's Activity Measurement) - Simple method for evaluating anti-biofilm activity of drug-saturated dressings against wound pathogens.}, journal = {Journal of microbiological methods}, volume = {143}, number = {}, pages = {6-12}, doi = {10.1016/j.mimet.2017.09.014}, pmid = {28962915}, issn = {1872-8359}, mesh = {Anti-Bacterial Agents/*pharmacokinetics/*pharmacology ; Bacteria/*drug effects/*growth & development ; Bandages/*microbiology ; Biofilms/*drug effects ; }, abstract = {In the present article, we propose a simple Antibiofilm Dressing's Activity Measurement (A.D.A.M.) test that allows to check in vitro a dressing's suitability against biofilm-related wound infections. To perform the test, three agar discs are covered with biofilm formed by the tested pathogen after which they are assembled one over another in the form of an agar plug and placed in the well of a 24-well plate. The top disc is covered with the analyzed dressing and the entire set is incubated for 24h. During this time, the investigated antimicrobial substance is released from the dressing and penetrates to subsequent biofilm-covered agar discs. Biofilm reduction is measured using 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) spectrometric assay and the results are compared to untreated control samples (agar plug covered with biofilm and without the dressing/or with a passive dressing placed on the top disc). Furthermore, in order to standardize the differences in penetrability of the drugs released from active dressings the results can be expressed as a dimensionless value referred to as the Penetrability Index. In summary, A.D.A.M. test is simple, cheap, can be performed practically in every clinical laboratory and takes no more time than routine microbiological diagnostics. Apart from measuring the released drug's activity, the A.D.A.M. test allows to assess drug penetrability (across three agar discs), reflecting real wound conditions, where microbes are frequently hidden under the necrotic tissue or cloth. In conclusion, the A.D.A.M. test produces a high volume of data that, when analyzed, can provide a researcher with a valuable hint concerning the applicability of active dressings against specific biofilm pathogens in a particular setting.}, } @article {pmid28961884, year = {2017}, author = {Gonzalez Moreno, M and Trampuz, A and Di Luca, M}, title = {Synergistic antibiotic activity against planktonic and biofilm-embedded Streptococcus agalactiae, Streptococcus pyogenes and Streptococcus oralis.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {11}, pages = {3085-3092}, doi = {10.1093/jac/dkx265}, pmid = {28961884}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Calorimetry ; Daptomycin/pharmacology ; Fosfomycin/pharmacology ; Gentamicins/pharmacology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Plankton/drug effects ; Streptococcal Infections/microbiology ; Streptococcus agalactiae/*drug effects/physiology ; Streptococcus oralis/*drug effects/physiology ; Streptococcus pyogenes/*drug effects/physiology ; }, abstract = {OBJECTIVES: To determine the antimicrobial activity against streptococcal biofilm in species mostly isolated from implant-associated infections and examine the effect of enzyme treatment of biofilm on the antimicrobial activity of different antibiotics.

METHODS: The activities of fosfomycin, rifampicin, benzylpenicillin, daptomycin, gentamicin, levofloxacin, proteinase K and their combinations on planktonic and/or biofilm-embedded standard laboratory strains of Streptococcus agalactiae, Streptococcus pyogenes and Streptococcus oralis were investigated in vitro by standard methods and isothermal microcalorimetry.

RESULTS: MIC values obtained for the tested antimicrobials against planktonic bacteria ranged from 0.016 to 128 mg/L for the three species tested. Higher antibiotic concentrations were usually required to reduce biofilm in comparison with planktonic bacteria, with the exception of gentamicin, for which similar concentrations (4-16 mg/L) exerted an effect on both planktonic and biofilm cells. A synergistic effect against the streptococcal biofilm of the three species was observed when gentamicin was combined with benzylpenicillin or with rifampicin. Moreover, antibiotic concentrations comparable to the MIC observed against planktonic cells induced a strong reduction of viable bacteria in proteinase K pre-treated biofilm.

CONCLUSIONS: This study shows that the combination of gentamicin with either benzylpenicillin or rifampicin exerts a synergistic effect against biofilms produced by the tested streptococci strains in vitro. Our results also suggest that coupling a dispersal agent with conventional antibiotics may facilitate their access to the bacteria within the biofilm. In vivo and clinical studies are needed in order to confirm whether such a strategy may be effective in the treatment of implant-associated infections caused by streptococci.}, } @article {pmid28961860, year = {2017}, author = {Maslennikova, IL and Kuznetsova, MV and Nekrasova, IV and Shirshev, SV}, title = {Effect of bacterial components of mixed culture supernatants of planktonic and biofilm Pseudomonas aeruginosa with commensal Escherichia coli on the neutrophil response in vitro.}, journal = {Pathogens and disease}, volume = {75}, number = {8}, pages = {}, doi = {10.1093/femspd/ftx105}, pmid = {28961860}, issn = {2049-632X}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; Escherichia coli/*physiology ; Homoserine/analogs & derivatives ; Humans ; Lactones ; Lipopolysaccharides ; Luminescent Measurements ; Neutrophils/*physiology ; Oligopeptides ; Peroxidase/metabolism ; Pseudomonas aeruginosa/*physiology ; Pyocyanine ; Reactive Oxygen Species ; }, abstract = {Pseudomonas aeruginosa (PA) responsible for acute and chronic infections often forms a well-organized bacterial population with different microbial species including commensal strains of Escherichia coli. Bacterial extracellular components of mixed culture can modulate the influence of bacteria on the neutrophil functions. The objective of this study was to compare the effect of pyocyanin, pyoverdine, LPS, exopolysaccharide of single species and mixed culture supernatants of PA strains and E. coli K12 on microbicidal, secretory activity of human neutrophils in vitro. Bacterial components of E. coli K12 in mixed supernatants with 'biofilm' PA strains (PA ATCC, PA BALG) enhanced short-term microbicidal mechanisms and inhibited neutrophil secretion delayed in time. The influence of 'planktonic' PA (PA 9-3) exometabolites in mixed culture is almost mimicked by E. coli K12 effect on functional neutrophil changes. This investigation may help to understand some of the mechanisms of neutrophil response to mixed infections of different PA with other bacteria species.}, } @article {pmid28960731, year = {2017}, author = {Wagner, S and Hauck, D and Hoffmann, M and Sommer, R and Joachim, I and Müller, R and Imberty, A and Varrot, A and Titz, A}, title = {Covalent Lectin Inhibition and Application in Bacterial Biofilm Imaging.}, journal = {Angewandte Chemie (International ed. in English)}, volume = {56}, number = {52}, pages = {16559-16564}, pmid = {28960731}, issn = {1521-3773}, mesh = {Adhesins, Bacterial/chemistry/metabolism ; Binding Sites ; Biofilms/drug effects/growth & development ; Carbohydrates/chemistry ; Crystallography, X-Ray ; Drug Design ; Epoxy Compounds/chemistry/metabolism/pharmacology ; Lectins/antagonists & inhibitors/*metabolism ; Pseudomonas aeruginosa/*physiology ; Virulence Factors/antagonists & inhibitors/metabolism ; }, abstract = {Biofilm formation by pathogenic bacteria is a hallmark of chronic infections. In many cases, lectins play key roles in establishing biofilms. The pathogen Pseudomonas aeruginosa often exhibiting various drug resistances employs its lectins LecA and LecB as virulence factors and biofilm building blocks. Therefore, inhibition of the function of these proteins is thought to have potential in developing "pathoblockers" preventing biofilm formation and virulence. A covalent lectin inhibitor specific to a carbohydrate binding site is described for the first time. Its application in the LecA-specific in vitro imaging of biofilms formed by P. aeruginosa is also reported.}, } @article {pmid28959742, year = {2017}, author = {Donner, J and Reck, M and Bunk, B and Jarek, M and App, CB and Meier-Kolthoff, JP and Overmann, J and Müller, R and Kirschning, A and Wagner-Döbler, I}, title = {The Biofilm Inhibitor Carolacton Enters Gram-Negative Cells: Studies Using a TolC-Deficient Strain of Escherichia coli.}, journal = {mSphere}, volume = {2}, number = {5}, pages = {}, pmid = {28959742}, issn = {2379-5042}, abstract = {The myxobacterial secondary metabolite carolacton inhibits growth of Streptococcus pneumoniae and kills biofilm cells of the caries- and endocarditis-associated pathogen Streptococcus mutans at nanomolar concentrations. Here, we studied the response to carolacton of an Escherichia coli strain that lacked the outer membrane protein TolC. Whole-genome sequencing of the laboratory E. coli strain TolC revealed the integration of an insertion element, IS5, at the tolC locus and a close phylogenetic relationship to the ancient E. coli K-12. We demonstrated via transcriptome sequencing (RNA-seq) and determination of MIC values that carolacton penetrates the phospholipid bilayer of the Gram-negative cell envelope and inhibits growth of E. coli TolC at similar concentrations as for streptococci. This inhibition is completely lost for a C-9 (R) epimer of carolacton, a derivative with an inverted stereocenter at carbon atom 9 [(S) → (R)] as the sole difference from the native molecule, which is also inactive in S. pneumoniae and S. mutans, suggesting a specific interaction of native carolacton with a conserved cellular target present in bacterial phyla as distantly related as Firmicutes and Proteobacteria. The efflux pump inhibitor (EPI) phenylalanine arginine β-naphthylamide (PAβN), which specifically inhibits AcrAB-TolC, renders E. coli susceptible to carolacton. Our data indicate that carolacton has potential for use in antimicrobial chemotherapy against Gram-negative bacteria, as a single drug or in combination with EPIs. Strain E. coli TolC has been deposited at the DSMZ; together with the associated RNA-seq data and MIC values, it can be used as a reference during future screenings for novel bioactive compounds. IMPORTANCE The emergence of pathogens resistant against most or all of the antibiotics currently used in human therapy is a global threat, and therefore the search for antimicrobials with novel targets and modes of action is of utmost importance. The myxobacterial secondary metabolite carolacton had previously been shown to inhibit biofilm formation and growth of streptococci. Here, we investigated if carolacton could act against Gram-negative bacteria, which are difficult targets because of their double-layered cytoplasmic envelope. We found that the model organism Escherichia coli is susceptible to carolacton, similar to the Gram-positive Streptococcus pneumoniae, if its multidrug efflux system AcrAB-TolC is either inactivated genetically, by disruption of the tolC gene, or physiologically by coadministering an efflux pump inhibitor. A carolacton epimer that has a different steric configuration at carbon atom 9 is completely inactive, suggesting that carolacton may interact with the same molecular target in both Gram-positive and Gram-negative bacteria.}, } @article {pmid28959353, year = {2017}, author = {Attaran, B and Falsafi, T}, title = {Identification of Factors Associated with Biofilm Formation Ability in the Clinical Isolates of Helicobacter pylori.}, journal = {Iranian journal of biotechnology}, volume = {15}, number = {1}, pages = {58-66}, pmid = {28959353}, issn = {1728-3043}, abstract = {BACKGROUND: A few reports confirm the ability of Helicobacter pylori to form biofilm. However, conclusive data do not exist concerning the factors that favor this ability.

OBJECTIVES: Evaluation of the factors associated with the biofilm formation ability of H. pylori including bacterial, physical and chemical, and environmental factors was the research's aim.

MATERIALS AND METHODS: H. pylori isolates from gastric biopsy specimens of patients infected chronically were screened for biofilm formation ability. Association of bacterial properties such as motility, auto-aggregation, cell hydrophobicity, and extracellular polymeric substances (EPS) with in vitro biofilm formation ability of H. pylori was evaluated. The effects of environmental factors such as growth-medium, temperature, oxygen-tension, pH, β-cyclodextrin, gastric secreted mucins, and sub-inhibitory concentration of amoxicillin were also evaluated.

RESULTS: Ability of clinical H. pylori isolates to form biofilm in was quantitatively compared. The coccoid shape H. pylori cells were observed by scanning electron microscopy, the images were illustrative of the attachment of cells to form microcolony. The levels of hydrophobicity, motility and auto aggregation of two isolates with highest and lowest biofilm formation ability were the same. However, the signifi cant role of mucins (P < 0.05) in elevating the biofilm formation was observed. Other factors influencing biofilm formation were: pH, atmosphere and sub-MIC of antibiotics.

CONCLUSION: Mucins have a signifi cant role in elevating the biofilm formation, also pH, atmosphere and sub-MIC of antibiotics influence biofilm formation.}, } @article {pmid28959249, year = {2017}, author = {Sinha-Ray, S and Ali, A}, title = {Mutation in flrA and mshA Genes of Vibrio cholerae Inversely Involved in vps-Independent Biofilm Driving Bacterium Toward Nutrients in Lake Water.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1770}, pmid = {28959249}, issn = {1664-302X}, support = {R01 AI039129/AI/NIAID NIH HHS/United States ; R01 AI097405/AI/NIAID NIH HHS/United States ; }, abstract = {Many bacterial pathogens promote biofilms that confer resistance against stressful survival conditions. Likewise Vibrio cholerae O1, the causative agent of cholera, and ubiquitous in aquatic environments, produces vps-dependent biofilm conferring resistance to environmental stressors and predators. Here we show that a 49-bp deletion mutation in the flrA gene of V. cholerae N16961S strain resulted in promotion of vps-independent biofilm in filter sterilized lake water (FSLW), but not in nutrient-rich L-broth. Complementation of flrA mutant with the wild-type flrA gene inhibited vps-independent biofilm formation. Our data demonstrate that mutation in the flrA gene positively contributed to vps-independent biofilm production in FSLW. Furthermore, inactivation of mshA gene, encoding the main pilin of mannose sensitive hemagglutinin (MSHA pilus) in the background of a ΔflrA mutant, inhibited vps-independent biofilm formation. Complementation of ΔflrAΔmshA double mutant with wild-type mshA gene restored biofilm formation, suggesting that mshA mutation inhibited ΔflrA-driven biofilm. Taken together, our data suggest that V. cholerae flrA and mshA act inversely in promoting vps-independent biofilm formation in FSLW. Using a standard chemotactic assay, we demonstrated that vps-independent biofilm of V. cholerae, in contrast to vps-dependent biofilm, promoted bacterial movement toward chitin and phosphate in FSLW. A ΔflrAΔmshA double mutant inhibited the bacterium from moving toward nutrients; this phenomenon was reversed with reverted mutants (complemented with wild-type mshA gene). Movement to nutrients was blocked by mutation in a key chemotaxis gene, cheY-3, although, cheY-3 had no effect on vps-independent biofilm. We propose that in fresh water reservoirs, V. cholerae, on repression of flagella, enhances vps-independent biofilm that aids the bacterium in acquiring nutrients, including chitin and phosphate; by doing so, the microorganism enhances its ability to persist under nutrient-limited conditions.}, } @article {pmid28958886, year = {2018}, author = {Jiang, Q and Ngo, HH and Nghiem, LD and Hai, FI and Price, WE and Zhang, J and Liang, S and Deng, L and Guo, W}, title = {Effect of hydraulic retention time on the performance of a hybrid moving bed biofilm reactor-membrane bioreactor system for micropollutants removal from municipal wastewater.}, journal = {Bioresource technology}, volume = {247}, number = {}, pages = {1228-1232}, doi = {10.1016/j.biortech.2017.09.114}, pmid = {28958886}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; *Biofilms ; *Bioreactors ; Membranes, Artificial ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {This study evaluated micropollutants removal and membrane fouling behaviour of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system at four different hydraulic retention times (HRTs) (24, 18, 12 and 6h). The results revealed that HRT of 18h was the optimal condition regarding the removal of most selected micropollutants. As the primary removal mechanism in the hybrid system was biodegradation, the attached growth pattern was desirable for enriching slow growing bacteria and developing a diversity of biocoenosis. Thus, the efficient removal of micropollutants was obtained. In terms of membrane fouling propensity analysis, a longer HRT (e.g. HRTs of 24 and 18h) could significantly mitigate membrane fouling when compared with the shortest HRT of 6h. Hence, enhanced system performance could be achieved when the MBBR-MBR system was operated at HRT of 18h.}, } @article {pmid28956494, year = {2018}, author = {Bogdan, M and Drenjancevic, D and Harsanji Drenjancevic, I and Bedenic, B and Zujic Atalic, V and Talapko, J and Vukovic, D}, title = {In vitro effect of subminimal inhibitory concentrations of antibiotics on the biofilm formation ability of Acinetobacter baumannii clinical isolates.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {30}, number = {1}, pages = {16-24}, doi = {10.1080/1120009X.2017.1378835}, pmid = {28956494}, issn = {1973-9478}, mesh = {Acinetobacter baumannii/*physiology ; Ampicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Azithromycin/pharmacology ; Biofilms/*drug effects ; Colistin/pharmacology ; Imipenem/pharmacology ; Microbial Sensitivity Tests ; Rifampin/pharmacology ; Sulbactam/pharmacology ; }, abstract = {The ability of A cinetobacter baumannii strains to form biofilm is one of the most important virulence factor which enables bacterial survival in a harsh environment and decreases antibiotic concentration as well. Subminimal inhibitory concentrations (subMICs) of antibiotics may change bacterial ultrastructure or have an influence on some different molecular mechanisms resulting in morphological or physiological changes in bacteria itself. The aim of this study was to determine effects of 1/2, 1/4, 1/8 and 1/16 minimal inhibitory concentrationsof imipenem, ampicillin-sulbactam, azithromycin, rifampicin and colistin on biofilm formation ability of 22 biofilm non-producing and 46 biofilm producing A. baumannii strains (30 weak producing strains and 16 moderate producing strains). Results of this study indicate that 1/2-1/16 MICs of imipenem, azithromycin, and rifampicin can reduce bacterial biofilm formation ability in moderate producing strains (p < 0.05), whereas 1/16 MIC of imipenem and 1/4-1/8 MICs of rifampicin reduce the biofilm formation in weak producing strains (p < 0.05). Statisticaly significant effect was detected among biofilm non-producing strains after their exposure to 1/16 MIC of azithromycin (p = 0.039). SubMICs of ampicillin-sulbactam and colistin did not have any significant effect on biofilm formation among tested A. baumannii strains.}, } @article {pmid28956426, year = {2017}, author = {Jiang, XH and Zhou, WM and He, YZ and Wang, Y and Lv, B and Wang, XM}, title = {Effects of lipopeptide carboxymethyl chitosan nanoparticles on Staphylococcus aureus biofilm.}, journal = {Journal of biological regulators and homeostatic agents}, volume = {31}, number = {3}, pages = {737-743}, pmid = {28956426}, issn = {0393-974X}, mesh = {*Bacterial Proteins/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; *Chitosan/chemistry/pharmacology ; *Lipopeptides/pharmacology ; Nanoparticles/*chemistry ; Staphylococcus aureus/*physiology ; }, abstract = {This study aims to evaluate the effect of lipopeptide carboxymethyl chitosan nanoparticles on Staphylococcus aureus biofilm as part of the development of a new anti-biofilm material. The study had three stages. Firstly, we assessed the Staphylococcus aureus capability to form biofilm and enumerated the number of attached bacteria and free bacteria; secondly, we determined the inhibitory effect of different concentrations of Bacillus natto antimicrobial lipopeptid- carboxymethyl chitosan (BNAP-CMCS) nanoparticles added at different times on biofilm formation capability and the numbers of free bacteria and attached bacteria. Lastly, we tested the scavenging effect of BNAP-CMCS nanoparticles on biofilm formation and number of attached bacteria. The results showed that the amount of attached bacteria quickly increased over time and reached the maximum after 24 h of culture. The BNAP-CMCS nanoparticles had the greatest effect on biofilm inhibition at the concentration of 1 MIC, after 8 h of culture, and the effect was dose-dependent. The BNAP-CMCS nanoparticles had decreased also the numbers of free and attached bacteria in a dose-dependent fashion, after 8 hours of culture. The scavenging effect of BNAP-CMCS nanoparticles on free and attached bacteria was maximum at 6 MIC. In conclusion, lipopeptide carboxymethyl chitosan nanoparticles had a good inhibition and scavenging effect on the formation of Staphylococcus aureus biofilm and the growth of surface-attached bacteria.}, } @article {pmid28956404, year = {2017}, author = {Zhao, C and Wang, N and Wang, W and Xu, Q}, title = {[Wastewater treatment based on biofilm regulation by Lux type quorum sensing system-a review].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1596-1610}, doi = {10.13345/j.cjb.170146}, pmid = {28956404}, issn = {1000-3061}, mesh = {Bacteria ; *Biofilms ; Bioreactors ; Extracellular Polymeric Substance Matrix ; *Quorum Sensing ; *Wastewater ; *Water Purification ; }, abstract = {Studies on biofilm regulation based on Lux type quorum sensing system in wastewater treatment have attracted much attention. The intervention of quorum sensing system includes both mechanisms of positive and negative control. The positive invigorating effect improves the efficiency of biofilm wastewater treatment, promotes the production of extracellular polymeric substance (EPS) and soluble microbial products (SMP), and increases the yield of biofilm. The negative weakening effect of quorum sensing can decompose the signal molecules needed in the process of biofilm formation, interrupts the gene expression process of biofilm formation, and inhibits the formation of biofilm on MBR membrane surface effectively. The further study of the structure and mechanism of N-acyl homoserine lactone (AHLs), the immobilization technology and application of quorum quenching bacteria, the synergistic effect verification of different biofouling control methods and the application feasibility of quorum sensing system based technology in more wastewater treatment fields are the next important researches to explore.}, } @article {pmid28956403, year = {2017}, author = {Wang, C and Wang, Y and Zheng, Y and Zhang, K and Hu, W and Shi, W and Li, Y}, title = {[Biofilm formation dominated by sophisticated social behaviors in Myxococcus xanthus].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1582-1595}, doi = {10.13345/j.cjb.170201}, pmid = {28956403}, issn = {1000-3061}, mesh = {Biofilms/*growth & development ; *Microbial Interactions ; Myxococcus xanthus/*growth & development ; }, abstract = {Myxococcus xanthus is a Gram-negative soil bacterium capable of performing sophisticated cellular behaviors and growing one of the most intricate bacterial single-species biofilms in nature. During the process of biofilm formation, social behaviors of M. xanthus cells dominate key steps of the biofilm establishment, e.g., cellular motility on solid surface, predatory behavior by the grouped cells, kin recognition in the community, fruiting body development, myxospore differentiation, and programmed cell death. This review introduces the recent research progress about the M. xanthus biofilms.}, } @article {pmid28956402, year = {2017}, author = {Guo, D and Yue, H and Wei, Y and Huang, G}, title = {[Genetic regulatory mechanisms of Candida albicans biofilm formation].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1567-1581}, doi = {10.13345/j.cjb.170122}, pmid = {28956402}, issn = {1000-3061}, mesh = {*Biofilms/drug effects ; Candida albicans/drug effects/*genetics/*growth & development ; Drug Resistance, Fungal ; Gene Expression Regulation, Fungal ; Signal Transduction ; }, abstract = {Candida albicans is an important opportunistic fungal pathogen of humans. Phenotypic plasticity is a typical biological feature of C. albicans, which is associated with pathogenicity, host adaptation, and sexual reproduction. Biofilm of C. albicans is a complex community formed by different morphological types of cells (yeast, hyphae and pseudohyphae) and secreted extracellular matrix. C. albicans biofilms are intrinsically resistant to antifungal drugs, the host immune system, and environmental stresses. Biofilm is an important virulence factor and a major clinical challenge. With the development of new technologies in global gene expression profiles and genetic manipulation, the regulatory mechanisms that govern C. albicans biofilm development and drug resistance become more and more clear. Major regulatory mechanisms involve the MAPK and cAMP signaling pathways and transcriptional regulators such as Bcr1 and Tec1. In addition, morphological transitions and sexual reproduction are also involved in the regulation of biofilm development. In this review, we focus on the genetic regulatory mechanisms of biofilm including the roles of cell-wall related proteins, transcription factors, and the MTL locus. In the last section, we also summarize the mechanisms of drug resistance of biofilm in C. albicans.}, } @article {pmid28956400, year = {2017}, author = {Xie, Z and Zhang, Z and Liu, L and Liu, X and Chen, Y}, title = {[Secondary metabolites from Streptococcus mutans and their ecological roles in dental biofilm].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1547-1554}, doi = {10.13345/j.cjb.170046}, pmid = {28956400}, issn = {1000-3061}, mesh = {Bacteriocins/metabolism ; *Biofilms ; Dental Caries/*microbiology ; Humans ; *Secondary Metabolism ; Streptococcus mutans/*metabolism ; }, abstract = {Dental biofilms are composed of hundreds of bacterial species, among which Streptococcus mutans is widely recognized as the major pathogen of dental caries. The cariogenic potential of S. mutans is related to its ability to form a robust biofilm on the tooth surface and its acidogenic and acid-tolerant properties. Co-evolution of S. mutans with the host has resulted in the diversity of secondary metabolism of S. mutans in strain level. A variety of secondary metabolites, including 10 bacteriocins (mutacins) and one hybrid Polyketide/Non-Ribosomal Peptide type compound, have been characterized. Studies on these secondary metabolites indicate that they play a significant role either in interspecies or in inter-kingdom interactions in the dental biofilm. As more S. mutans strains are isolated and sequenced, additional secondary metabolites with novel functions will be discovered. The study of secondary metabolites in S. mutans is anticipated to be helpful for oral disease treatment and prevention by providing new strategies.}, } @article {pmid28956399, year = {2017}, author = {Wang, Q and Ma, Y and Liu, L and Zhu, J and Liu, Z}, title = {[Biofilm development and environmental determinants in Vibrio cholerae].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1533-1546}, doi = {10.13345/j.cjb.170052}, pmid = {28956399}, issn = {1000-3061}, mesh = {*Biofilms ; Environment ; Gene Expression Regulation, Bacterial ; Vibrio cholerae/*growth & development ; }, abstract = {Biofilm associated Vibrio cholerae exhibits hypervirulence and supreme fitness against the harsh stresses during its infectious cycle. It is important to study the relationships between the regulation mechanism of V. cholerae biofilm development and its environmental adaption in host niche and aquatic habitat. Here, we summarize the recent advances in V. cholerae biofilm, including biofilm compositions, development and regulation. Particularly, we extensively discuss how V. cholerae fosters its biofilm architecture and assembly via sensing and responding various environmental determinants, such as bacterium self-produced molecules, natural environment components and host factors.}, } @article {pmid28956398, year = {2017}, author = {Zhu, Y and Chai, S and Cao, M and Wang, S and Feng, Z}, title = {[Discovery and analysis of Staphylococcus aureus biofilm inhibitors using functional metagenomics approach].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1525-1532}, doi = {10.13345/j.cjb.170058}, pmid = {28956398}, issn = {1000-3061}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Metagenomics ; Microbial Sensitivity Tests ; Soil Microbiology ; Staphylococcus aureus/*drug effects ; }, abstract = {Although most microbes are not readily cultured in the lab, microbial DNA can be extracted directly from an environmental sample and be functionally expressed in a suitable host for natural products discovery, and this approach has been termed "metagenomics". An E'mei Mountain soil metagenomic library was constructed using an Escherichia coli-Streptomyces shuttle vector for functional based screening of anti-bacterial clones in Streptomyces albus host. Two active clones were obtained and their fermentation broths were studied for the inhibitory effect on Staphylococcus aureus biofilm. Their fermentation products have a good inhibitory effect on the formation of S. aureus biofilm, and the inhibitory effect could exceed 90% when the concentration of sample was 2 MIC (Minimum Inhibitory Concentration). In addition, two samples had significantly effect on S. aureus biofilm dispersal, and the clearance rate of EM110 was higher than EM123. In conclusion, substances with strong bioactivities on biofilm formation and dispersal of S. aureus could be discovered by using metagenomics technology.}, } @article {pmid28956397, year = {2017}, author = {Zhao, J and Sun, Y}, title = {[Regulation of c-di-GMP metabolism and biofilm formation in Yersinia pestis].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1513-1524}, doi = {10.13345/j.cjb.170073}, pmid = {28956397}, issn = {1000-3061}, mesh = {Animals ; Bacterial Proteins ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins ; Phosphorus-Oxygen Lyases ; *Second Messenger Systems ; Siphonaptera/microbiology ; Yersinia pestis/*growth & development ; }, abstract = {Yersinia pestis, the cause of plague, is transmitted by flea bite. Y. pestis forms a biofilm in the proventriculus of its flea vector to enhance transmission. Biofilm formation in Y. pestis is positively regulated by the intracellular levels of the second messenger cyclic diguanylate (c-di-GMP). The c-di-GMP in Y. pestis is synthesized by two diguanylate cyclases (DGC), HmsT and HmsD, and degraded by phosphodiesterase (PDE), HmsP. Here we summarized the regulators that modulate c-di-GMP metabolism and biofilm formation in Y. pestis and discussed their regulatory mechanism.}, } @article {pmid28956396, year = {2017}, author = {Yu, S and Ma, L}, title = {[Iron uptake and biofilm formation in Pseudomonas aeruginosa].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1489-1512}, doi = {10.13345/j.cjb.170140}, pmid = {28956396}, issn = {1000-3061}, mesh = {*Biofilms ; Cystic Fibrosis/microbiology ; Extracellular Polymeric Substance Matrix ; Humans ; Iron/*metabolism ; Pseudomonas Infections ; Pseudomonas aeruginosa/growth & development/*metabolism ; Quorum Sensing ; }, abstract = {Biofilms are surface-associated communities of microorganisms embedded within self-secreted extracellular polymeric substances, and a major cause of chronic and persistent infections. Respiratory Pseudomona aeruginosa infection is the leading reason for morbidity and mortality in cystic fibrosis patients. The formation of biofilms by P. aeruginosa in the airway is thought to increase persistence and antibiotic resistance during infection. Biofilm formation of P. aeruginosa is regulated by complicated signaling systems including quorum sensing and two-component systems that control the synthesis of extracellular polymeric substances. Furthermore, iron is an essential and scarce nutrient for bacteria and an important signal factor. P. aeruginosa has developed multiple iron uptake systems to sequester enough iron for its survival, with important regulatory roles in both release of virulence factors and formation of biofilms. In this review, we summarize recent advances in biofilm formation and its regulation along with the iron-uptake strategies in P. aeruginosa, to provide new insights and understanding to fight bacterial biofilms.}, } @article {pmid28956395, year = {2017}, author = {Yu, S and Zhang, M and Ma, L}, title = {[Anti-biofilm effects of Zn lactate·3H2O and SnF2 on Pseudomonas aeruginosa, Acinetobacter baumannii and Streptococcus mutans].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1478-1488}, doi = {10.13345/j.cjb.170141}, pmid = {28956395}, issn = {1000-3061}, mesh = {Acinetobacter baumannii/drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Lactic Acid/*pharmacology ; Polysaccharides, Bacterial ; Pseudomonas aeruginosa/drug effects ; Streptococcus mutans/drug effects ; Zinc/*pharmacology ; }, abstract = {Zn lactate and SnF2 were used as active compounds in the dentifrice. Here, their anti-biofilm effects were evaluated on Pseudomonas aeruginosa, Acinetobacter baumannii and Streptococcus mutans. The biofilm prevention/dispersal assay of P. aeruginosa PAO1 demonstrated that Zn lactate and SnF2 can inhibit biofilm formation independently or by combined treatment. Zn lactate disrupted extracellular polysaccharides matrix formation and SnF2 reduced the biomass of biofilm. Most importantly, the combination of Zn lactate and SnF2 thoroughly abolished the biofilm formation of all three strains.}, } @article {pmid28956393, year = {2017}, author = {Liu, X and Xiang, X and Tao, H and Cui, Z and Zhang, L}, title = {[Chemical agents modulating bacterial biofilm formation and development].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1433-1465}, doi = {10.13345/j.cjb.170133}, pmid = {28956393}, issn = {1000-3061}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects ; }, abstract = {Biofilm is a bacterial lifestyle ubiquitously in natural environments. Bacterial biofilm leads to drug resistance, a main reason why many infectious diseases are difficult to control. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. This review introduces chemical agents that could modulate bacterial biofilm formation and development.}, } @article {pmid28956388, year = {2017}, author = {Peng, X and Li, J and Xu, X}, title = {[c-di-AMP regulates bacterial biofilm formation].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1369-1375}, doi = {10.13345/j.cjb.170078}, pmid = {28956388}, issn = {1000-3061}, mesh = {Bacteria/*growth & development ; *Biofilms ; Dinucleoside Phosphates/*physiology ; *Second Messenger Systems ; }, abstract = {Bacterial biofilm plays an important role in persistent microbial infection. Delineation of the formation and development of bacterial biofilm would provide a promising strategy to treat recalcitrant infection. c-di-AMP (Cyclic diadenosine monophosphate) is a recently identified second messenger of bacteria and involved in plethora of bacterial activities, including cell growth, cell wall homeostasis, biofilm formation and microbial pathogenicity. Here we review the recent literature pertinent to the role and molecular mechanisms of c-di-AMP in regulating biofilm formation of bacteria. The potential application of c-di-AMP and its related proteins in the development of novel antimicrobial therapeutics has also been discussed.}, } @article {pmid28956386, year = {2017}, author = {Qian, W and Ma, L and Gu, L and Zhang, L}, title = {[Preface for special issue on biofilm and c-di-GMP--Microbial society, c-di-GMP regulation, and new research techniques].}, journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology}, volume = {33}, number = {9}, pages = {1351-1356}, doi = {10.13345/j.cjb.170353}, pmid = {28956386}, issn = {1000-3061}, mesh = {*Biofilms ; Cyclic GMP/*analogs & derivatives/physiology ; *Second Messenger Systems ; }, abstract = {Biofilm is prevalent in various ecological niches, in which microbial cells interconnect with each other through extracellular polymeric substances including polysaccharides, extracellular DNA, and proteins. When living in biofilms, the microbial cells employ small signalling chemicals as their "language" to communicate mutually, and exhibit remarkable differences in physiology compared to those living in planktonic state. It has been proven that the development of biofilm is subject to the regulation of c-di-GMP, an important second messenger found in prokaryotes. Given its important roles of biofilms in microbial infection, industry application, plant-microbe interactions and environmental pollustion, biofilm is one of frontier research areas in microbiology. This special issue of "Biofilm and c-di-GMP" systematically reviews the current progresses in the multiple research frontiers, including biotechnology, infectious diseases, environmental microbiology and plant pathology, with special focus on the methods and techniques in biofilm research. We hope that the issue will boost the interest of students and young scientists in this exciting area of microbiology.}, } @article {pmid28956352, year = {2017}, author = {Jung, HI and Kim, YJ and Lee, YJ and Lee, HS and Lee, JK and Kim, SK}, title = {Mutation of the cyclic di-GMP phosphodiesterase gene in Burkholderia lata SK875 attenuates virulence and enhances biofilm formation.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {55}, number = {10}, pages = {800-808}, pmid = {28956352}, issn = {1976-3794}, mesh = {3',5'-Cyclic-GMP Phosphodiesterases/deficiency/*genetics/*physiology ; Animals ; Bacterial Proteins/genetics/physiology ; Biofilms/*growth & development ; Burkholderia/cytology/*enzymology/*genetics/growth & development ; Caenorhabditis elegans/genetics ; Chromosome Mapping ; DNA Transposable Elements/genetics ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Genes, Bacterial/*genetics ; Locomotion ; Mutation ; Phenotype ; Quorum Sensing ; Republic of Korea ; Sequence Analysis, DNA ; Sequence Homology, Nucleic Acid ; Swine ; Virulence ; Virulence Factors/deficiency/*genetics/physiology ; }, abstract = {Burkholderia sp. is a gram-negative bacterium that commonly exists in the environment, and can cause diseases in plants, animals, and humans. Here, a transposon mutant library of a Burkholderia lata isolate from a pig with swine respiratory disease in Korea was screened for strains showing attenuated virulence in Caenorhabditis elegans. One such mutant was obtained, and the Tn5 insertion junction was mapped to rpfR, a gene encoding a cyclic di-GMP phosphodiesterase that functions as a receptor. Mutation of rpfR caused a reduction in growth on CPG agar and swimming motility as well as a rough colony morphology on Congo red agar. TLC analysis showed reduced AHL secretion, which was in agreement with the results from plate-based and bioluminescence assays. The mutant strain produced significantly more biofilm detected by crystal violet staining than the parent strain. SEM of the mutant strain clearly showed that the overproduced biofilm contained a filamentous structure. These results suggest that the cyclic di-GMP phosphodiesterase RpfR plays an important role in quorum sensing modulation of the bacterial virulence and biofilm formation.}, } @article {pmid28956275, year = {2018}, author = {Pompilio, A and Galardi, G and Gherardi, G and Verginelli, F and Geminiani, C and Pilloni, AP and Catalanotti, P and Di Bonaventura, G}, title = {Infection of recurrent calcaneal ulcer caused by a biofilm-producer Myroides odoratimimus strain.}, journal = {Folia microbiologica}, volume = {63}, number = {2}, pages = {203-207}, pmid = {28956275}, issn = {1874-9356}, mesh = {Aged ; *Biofilms ; Calcaneus/*microbiology ; Flavobacteriaceae/genetics/*isolation & purification/*physiology ; Flavobacteriaceae Infections/*microbiology ; Humans ; Male ; Soft Tissue Infections/*microbiology ; Ulcer/diagnosis/*microbiology ; }, abstract = {We report a case of recurrent post-traumatic ulcer infection due to Myroides odoratimimus in an immunocompromised male. We have also reviewed the medical literature on isolated M. odoratimimus infections. The strain, isolated from ulcer discharge, was multidrug-resistant and treatment with meropenem, based on susceptibility testing, led to resolution of infection. The strain was also able to form a relevant amount of biofilm over time, thus suggesting a possible role of sessile communities in the chronicization of infection. To our knowledge, this is the first description of recurrent ulcer infection caused by a biofilm-producer M. odoratimimus strain. This case reminds us of the need to consider uncommon pathogens as etiology of skin and soft tissue infections, especially in immunocompromised patients. Further, since the treatment of infections due to M. odoratimimus is often difficult both due to multidrug resistance and scarce clinical experience, antibiotic therapy should be adapted to in vitro susceptibility testing.}, } @article {pmid28956213, year = {2017}, author = {Cwalina, B and Dec, W and Michalska, JK and Jaworska-Kik, M and Student, S}, title = {Initial stage of the biofilm formation on the NiTi and Ti6Al4V surface by the sulphur-oxidizing bacteria and sulphate-reducing bacteria.}, journal = {Journal of materials science. Materials in medicine}, volume = {28}, number = {11}, pages = {173}, pmid = {28956213}, issn = {1573-4838}, mesh = {Acidithiobacillus thiooxidans/*drug effects/metabolism/physiology ; Alloys ; Bacteria/drug effects/growth & development/metabolism ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Desulfovibrio desulfuricans/*drug effects/metabolism/physiology ; Humans ; Microbial Sensitivity Tests ; Nickel/chemistry/*pharmacology ; Oxidation-Reduction ; Sulfates/metabolism ; Sulfur/metabolism ; Surface Properties ; Titanium/chemistry/*pharmacology ; }, abstract = {The susceptibility to the fouling of the NiTi and Ti6Al4V alloys due to the adhesion of microorganisms and the biofilm formation is very significant, especially in the context of an inflammatory state induced by implants contaminated by bacteria, and the implants corrosion stimulated by bacteria. The aim of this work was to examine the differences between the sulphur-oxidizing bacteria (SOB) and sulphate-reducing bacteria (SRB) strains in their affinity for NiTi and Ti6Al4V alloys. The biofilms formed on alloy surfaces by the cells of five bacterial strains (aerobic SOB Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans, and anaerobic SRB Desulfovibrio desulfuricans-3 strains) were studied using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The protein concentrations in liquid media have also been analyzed. The results indicate that both alloys tested may be colonized by SOB and SRB strains. In the initial stage of the biofilm formation, the higher affinity of SRB to both the alloys has been documented. However, the SOB strains have indicated the higher (although differentiated) adaptability to changing environment as compared with SRB. Stimulation of the SRB growth on the alloys surface was observed during incubation in the liquid culture media supplemented with artificial saliva, especially of lower pH (imitated conditions under the inflammatory state, for example in the periodontitis course). The results point to the possible threat to the human health resulting from the contamination of the titanium implant alloys surface by the SOB (A. thiooxidans and A. ferrooxidans) and SRB (D. desulfuricans).}, } @article {pmid28955316, year = {2017}, author = {Liu, Y and Xu, Y and Song, Q and Wang, F and Sun, L and Liu, L and Yang, X and Yi, J and Bao, Y and Ma, H and Huang, H and Yu, C and Huang, Y and Wu, Y and Li, Y}, title = {Anti-biofilm Activities from Bergenia crassifolia Leaves against Streptococcus mutans.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1738}, pmid = {28955316}, issn = {1664-302X}, abstract = {Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. The bacteria can produce glucosyltransferases (Gtfs) to synthesize extracellular polysaccharides (EPSs) that are known as virulence factors for adherence and formation of biofilms. Therefore, an ideal inhibitor for dental caries is one that can inhibit planktonic bacteria growth and prevent biofilm formation. Bergenia crassifolia (L.), widely used as a folk medicine and tea beverage, has been reported to have a variety of bioactivities. The present study aimed to explore the effect of B. crassifolia (L.) leaf extracts on the biofilm of Streptococcus mutans. The B. crassifolia (L.) leaf extracts showed inhibitory effects by decreasing viability of bacteria within the biofilm, as evidenced by the XTT assay, live/dead staining assay and LDH activity assay, and could decrease the adherence property of S. mutans through inhibiting Gtfs to synthesize EPSs. In addition, the reduced quantity of EPSs and the inhibition of Gtfs were positively correlated with concentrations of test samples. Finally, the MTT assay showed that the extracts had no cytotoxicity against normal oral cells. In conclusion, the extracts and sub-extracts of B. crassifolia leaves were found to be antimicrobial and could reduce EPS synthesis by inhibiting activities of Gtfs to prevent bacterial adhesion and biofilm formation. Therefore, B. crassifolia leaves have potential to be developed as a drug to prevent and cure dental caries.}, } @article {pmid28954819, year = {2017}, author = {Chua, SL and Ding, Y and Liu, Y and Cai, Z and Zhou, J and Swarup, S and Drautz-Moses, DI and Schuster, SC and Kjelleberg, S and Givskov, M and Yang, L}, title = {Correction to 'Reactive oxygen species drive evolution of pro-biofilm variants in pathogens by modulating cyclic-di-GMP levels'.}, journal = {Open biology}, volume = {7}, number = {9}, pages = {}, doi = {10.1098/rsob.170197}, pmid = {28954819}, issn = {2046-2441}, } @article {pmid28954082, year = {2017}, author = {Paula-Mattiello, S and Oliveira, SD and Medina-Silva, R}, title = {In vitro evaluation of hydrolytic enzyme activity and biofilm formation of Candida parapsilosis species complex from a nosocomial environment.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {50}, number = {4}, pages = {558-561}, doi = {10.1590/0037-8682-0032-2017}, pmid = {28954082}, issn = {1678-9849}, mesh = {Biofilms/*growth & development ; Candida/*enzymology/isolation & purification/metabolism ; Health Facility Environment ; Hydrolysis ; Peptide Hydrolases/*biosynthesis ; Phospholipases/*biosynthesis ; }, abstract = {INTRODUCTION:: Candida parapsilosis complex species, frequently found in hospital environments, have gained importance as etiological agents of candidemia.

METHODS:: Candida parapsilosis complex isolates from a nosocomial environment were identified and their hydrolitic enzyme activity and ability to form biofilm were characterized.

RESULTS:: Twenty-two C. parapsilosis sensu stricto isolates produced proteinase and three produced phospholipase. Most Candida metapsilosis isolates produced proteinase and one also produced phospholipase. All 29 isolates formed biofilms.

CONCLUSIONS:: The nosocomial environment may act as a reservoir for C. parapsilosis complex isolates with phenotypic features that could possibly lead to nosocomial infections and health complications in hospital patients.}, } @article {pmid28953747, year = {2017}, author = {Deva, AK}, title = {Reply: The Role of Bacterial Biofilm in Adverse Soft-Tissue Filler Reactions: A Combined Laboratory and Clinical Study.}, journal = {Plastic and reconstructive surgery}, volume = {140}, number = {4}, pages = {633e-634e}, doi = {10.1097/PRS.0000000000003724}, pmid = {28953747}, issn = {1529-4242}, mesh = {Biocompatible Materials ; *Biofilms ; *Cosmetic Techniques ; Humans ; Hyaluronic Acid ; }, } @article {pmid28951073, year = {2018}, author = {Dias, C and Borges, A and Saavedra, MJ and Simões, M}, title = {Biofilm formation and multidrug-resistant Aeromonas spp. from wild animals.}, journal = {Journal of global antimicrobial resistance}, volume = {12}, number = {}, pages = {227-234}, doi = {10.1016/j.jgar.2017.09.010}, pmid = {28951073}, issn = {2213-7173}, mesh = {Aeromonas/*drug effects/genetics/*isolation & purification/physiology ; Animals ; Animals, Wild/*microbiology ; Anti-Bacterial Agents/*pharmacology ; *Biofilms/drug effects ; Ciprofloxacin/pharmacology ; Deer/microbiology ; *Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Snakes/microbiology ; Strigiformes/microbiology ; }, abstract = {OBJECTIVES: The 'One Health' concept recognises that the health of humans, animals and the environment are interconnected. Therefore, knowledge on the behaviour of micro-organisms from the most diverse environmental niches is important to prevent the emergence and dissemination of antimicrobial resistance. Wild animals are known to carry antimicrobial-resistant micro-organisms with potential public health impact. However, no data are available on the behaviour of sessile bacteria from wild animals, although antimicrobial resistance is amplified in biofilms. This study characterised the ciprofloxacin susceptibility and the adhesion and biofilm formation abilities of 14 distinct Aeromonas spp. (8 Aeromonas salmonicida, 3 Aeromonas eucrenophila, 2 Aeromonas bestiarum and 1 Aeromonas veronii) isolated from wild animals and already characterised as resistant to β-lactam antibiotics.

METHODS: The ciprofloxacin MIC was determined according to CLSI guidelines. A biofilm formation assay was performed by a modified microtitre plate method. Bacterial surface hydrophobicity was assessed by sessile drop contact angle measurement.

RESULTS: All Aeromonas spp. strains were resistant to ciprofloxacin (MICs of 6-60μg/mL) and had hydrophilic surfaces (range 2-37mJ/m[2]). These strains were able to adhere and form biofilms with distinct magnitudes. Biofilm exposure to 10×MIC of ciprofloxacin only caused low to moderate biofilm removal.

CONCLUSIONS: This study shows that the strains tested are of potential public health concern and emphasises that wild animals are potential reservoirs of multidrug-resistant strains. In fact, Aeromonas spp. are consistently considered opportunistic pathogens. Moreover, bacterial ability to form biofilms increases antimicrobial resistance and the propensity to cause persistent infections.}, } @article {pmid28950141, year = {2018}, author = {Huang, H and Yu, Q and Ren, H and Geng, J and Xu, K and Zhang, Y and Ding, L}, title = {Towards physicochemical and biological effects on detachment and activity recovery of aging biofilm by enzyme and surfactant treatments.}, journal = {Bioresource technology}, volume = {247}, number = {}, pages = {319-326}, doi = {10.1016/j.biortech.2017.09.082}, pmid = {28950141}, issn = {1873-2976}, mesh = {Bacteria ; Biofilms ; *Bioreactors ; Surface-Active Agents ; Wastewater ; }, abstract = {In order to explore physicochemical and biological effects on detachment and activity recovery of aging biofilm by enzyme and surfactant treatments, two kinds of biofilm processes, i.e. biological aeration filter (BAF) and moving bed biofilm reactor (MBBR), and multiple indicators including water quality, biofilm morphology, activity and microbial community structure, were employed. Results showed that detachment of aging biofilm was mainly attributed by extracellular polymeric substance (EPS) solubilization and dispersion, and activity recovery of aging biofilm mainly depended on biological effects of dominant bacteria. Phosphorus metabolism related bacteria, such as Microbacterium and Micropruina, were responsible for BAF biofilm regeneration. More abundant microbial community structure of MBBR regenerated biofilm was found, and biofilm activity was not only related to phosphorus metabolism related bacteria, but also to denitrifying bacteria. Rhamnolipid performed best on aging biofilm detachment and regeneration, giving a clue for effective activation of aging biofilm in wastewater treatment systems.}, } @article {pmid28950134, year = {2018}, author = {Ren, LF and Lv, L and Kang, Q and Gao, B and Ni, SQ and Chen, YH and Xu, S}, title = {Microbial dynamics of biofilm and suspended flocs in anammox membrane bioreactor: The effect of non-woven fabric membrane.}, journal = {Bioresource technology}, volume = {247}, number = {}, pages = {259-266}, doi = {10.1016/j.biortech.2017.09.070}, pmid = {28950134}, issn = {1873-2976}, mesh = {Anaerobiosis ; Bacteria ; *Biofilms ; *Bioreactors ; Nitrogen ; Oxidation-Reduction ; }, abstract = {Membrane bioreactor with non-woven fabric membranes (NWMBR) is developing into a suitable method for anaerobic ammonium oxidation (anammox). As a carrier, non-woven fabric membrane divided total biomass into biofilm and suspended flocs gradually. Total nitrogen removal efficiency was maintained around 82.6% under nitrogen loading rate of 567.4mgN/L/d after 260days operation. Second-order substrate removal and Stover-Kincannon models were successfully used to simulate the nitrogen removal performance in NWMBR. High-throughput sequence was employed to elucidate the underlying microbial community dynamics. Candidatus Brocadia, Kuenenia, Jettenia were detected to affirm the dominant status of anammox microorganisms and 98.2% of anammox microorganisms distributed in biofilm. In addition, abundances of functional genes (hzs, nirK) in biofilm and suspended flocs were assessed by quantitative PCR to further investigate the coexistence of anammox and other microorganisms. Potential nitrogen removal pathways were established according to relevant nitrogen removal performance and microbial community.}, } @article {pmid28950041, year = {2017}, author = {Xu, Y and Chen, W and You, C and Liu, Z}, title = {Development of a Multiplex PCR Assay for Detection of Pseudomonas fluorescens with Biofilm Formation Ability.}, journal = {Journal of food science}, volume = {82}, number = {10}, pages = {2337-2342}, doi = {10.1111/1750-3841.13845}, pmid = {28950041}, issn = {1750-3841}, mesh = {Animals ; *Biofilms/growth & development ; Cattle ; Food Contamination ; Milk/*microbiology ; Multiplex Polymerase Chain Reaction/*methods ; Phylogeny ; Pseudomonas fluorescens/classification/genetics/*isolation & purification/physiology ; }, abstract = {UNLABELLED: Under the cold storage and processing conditions of raw milk, the psychrotrophic Pseudomonas fluorescens is usually found as predominant bacteria causing its spoilage. In this study, a multiplex PCR assay was developed for rapid and selective detection of P. fluorescens with biofilm formation ability. The target sequences were 2 genes (adnA and fliC) related to biofilm formation and flagella biosynthesis of P. fluorescens. The specificity of the mPCR assay was evaluated with 7 reference strains, isolated from raw milk, belonging to P. fluorescens, Pseudomonas fragi, Pseudomonas lundensis, Pseudomonas putida, Pseudomonas monteilii, and 2 unclassified Pseudomonas species (Pseudomonas sp1 and Pseudomonas sp8). The detection limit for the target strain was 10[2] CFU/mL. Seventy-three strains were evaluated by the mPCR assay. The adnA gene was detected in 23 strains while fliC gene was detected in only 3 strains. However, both target genes (adnA and fliC) were detected by amplification in 12 strains belonging to P. fluorescens species. The biofilm formation ability of P. fluorescens following cultivation in 10% UHT milk at 30 °C or 4 °C were evaluated by the microtiter plate assay. The result showed that all the P. fluorescens strains with the target gene (adnA or fliC, or both 2 genes) had the biofilm-forming ability. The phylogenetic analysis showed that adnA gene tree had a higher resolution than rpoB tree, and the strains in adnA phylogenetic dendrogram could be divided into 4 different groups according with the matrix of their biofilm-forming ability. The results indicated a promising use of adnA gene as a taxonomic marker for subdividing P. fluorescens.

PRACTICAL APPLICATION: A mPCR assay targeting adnA and fliC genes showed rapid and reliable detection of P. fluorescens with biofilm formation ability, which could be useful to detect this contamination in milk samples.}, } @article {pmid28948954, year = {2017}, author = {Lahkar, V and Saikia, L and Patgiri, SJ and Nath, R and Das, PP}, title = {Estimation of biofilm, proteinase & phospholipase production of the Candida species isolated from the oropharyngeal samples in HIV-infected patients.}, journal = {The Indian journal of medical research}, volume = {145}, number = {5}, pages = {635-640}, pmid = {28948954}, issn = {0971-5916}, mesh = {AIDS-Related Opportunistic Infections/enzymology/genetics/*microbiology ; Adult ; Biofilms/*growth & development ; Candida albicans/*enzymology/pathogenicity ; Female ; HIV Infections/enzymology/*microbiology/virology ; Humans ; Male ; Peptide Hydrolases/biosynthesis ; Phospholipases/biosynthesis ; }, abstract = {BACKGROUND & OBJECTIVES: Candida, the most common opportunistic infection in acquired immunodeficiency syndrome (AIDS), attributes its pathogenicity to its virulence factors, mainly the biofilms, the proteinases and the phospholipases. There is a significant interplay of these factors during the HIV infection. This study was aimed to estimate the biofilm, proteinase and phospholipase production in Candida species isolated from the oropharyngeal samples in the HIV-infected patients.

METHODS: A total of 126 consecutive HIV-positive patients were screened for Candida growth using oropharyngeal swabs. Identification was done by Gram staining, germ tube test, chlamydospore identification, chromagar and biochemical tests on Vitek 2. Biofilm production was observed on Sabouraud's dextrose broth with glucose, phospholipase production in egg yolk agar medium and proteinase production in bovine serum albumin agar medium.

RESULTS: Of a total of 126 patients, 53 (42.06%) showed Candida growth: Candida albicans (n=46, 86.8%) was most common followed by the non-albicans Candida (NAC) (n=7, 13.93%). Of a total 33 (62.3%) biofilm positive isolates, significant production was observed in the NAC species (P <0.05). C. albicans reported the highest phospholipase (n=37/41, 90.24%) and proteinase (n=37/43, 86%) activities in a total of 41 (77%) phospholipase positive and 43 (81.1%) proteinase positive isolates.

Although C. albicans was the most common Candida species identified in HIV positive patients, the emergence of NAC was of special concern. Virulence factors such as biofilms, proteinases and phospholipases were noted in both these groups. Further research is required for better understanding of the pathogenic role of Candida species so as to aid in therapeutic interventions.}, } @article {pmid28947672, year = {2017}, author = {Wang, X and Han, H and Lv, Z and Lin, Z and Shang, Y and Xu, T and Wu, Y and Zhang, Y and Qu, D}, title = {PhoU2 but Not PhoU1 as an Important Regulator of Biofilm Formation and Tolerance to Multiple Stresses by Participating in Various Fundamental Metabolic Processes in Staphylococcus epidermidis.}, journal = {Journal of bacteriology}, volume = {199}, number = {24}, pages = {}, pmid = {28947672}, issn = {1098-5530}, support = {K08 AA021404/AA/NIAAA NIH HHS/United States ; }, mesh = {ATP Synthetase Complexes/genetics/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Citric Acid Cycle/genetics ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Hydrogen Peroxide/pharmacology ; Membrane Transport Proteins/*genetics ; Mutation ; NADP/metabolism ; Operon ; Pentose Phosphate Pathway/genetics ; Phosphates/metabolism ; Staphylococcus epidermidis/drug effects/*genetics/growth & development/*metabolism ; Stress, Physiological ; }, abstract = {PhoU, a conserved protein that has been proposed to coordinate phosphate import, is a negative regulator of drug tolerance in most bacteria. In Staphylococcus epidermidis, the role of PhoU in biofilm formation and drug tolerance has not yet been investigated. Two PhoU homologs in the genome of S. epidermidis have been identified by the presence of the conserved motif E(D)XXXD of PhoU. We separately constructed ΔphoU1 and ΔphoU2 mutants of S. epidermidis strain 1457. The ΔphoU2 mutant displayed growth retardation, a weakened biofilm formation capacity, a higher sensitivity to H2O2, and reduced tolerance to multiple antibiotics. However, deletion of phoU1 had no effect on those. We compared the transcriptome profiles of the ΔphoU2 and ΔphoU1 mutants with that of the parent strain. In the ΔphoU2 mutant, expression of genes related to inorganic phosphate uptake was significantly upregulated (pst operon) and the levels of intracellular inorganic polyphosphate (polyP) were increased. In the ΔphoU2 mutant, expression of enzymes in the pentose phosphate pathway (PPP) was downregulated and less NADP (NADPH) was detected, consistent with the high sensitivity to H2O2 and the growth retardation of the ΔphoU2 mutant. The upregulated expression of ATP synthase was consistent with the high intracellular ATP content in the ΔphoU2 mutant, which may have been related to the lower drug tolerance of the ΔphoU2 mutant. This study demonstrates that PhoU2, but not PhoU1, in S. epidermidis regulates bacterial growth, biofilm formation, oxidative stress, and drug tolerance in association with alterations to inorganic phosphate metabolism, the pentose phosphate pathway, galactose metabolism, the tricarboxylic acid (TCA) or citric cycle, glycolysis and gluconeogenesis, and respiratory reactions.IMPORTANCE PhoU is widely conserved throughout the bacterial kingdom and plays an important role in response to stress and metabolic maintenance. In our study, two PhoU homologs were found in S. epidermidis The function of phoU2, but not phoU1, in S. epidermidis is related to growth, drug tolerance, the oxidative stress response, polyP levels, and ATP accumulation. In addition, phoU2 regulates biofilm formation. Hence, phoU2 is a regulator of both drug tolerance and biofilm formation, which are two bacterial properties that present major challenges to the clinical treatment of infections. Analysis of differential gene expression revealed that phoU2 is involved in fundamental metabolic processes, such as the PPP pathway. These findings indicate that phoU2 is a crucial regulator in S. epidermidis.}, } @article {pmid28947088, year = {2018}, author = {Todorov, SD and de Paula, OAL and Camargo, AC and Lopes, DA and Nero, LA}, title = {Combined effect of bacteriocin produced by Lactobacillus plantarum ST8SH and vancomycin, propolis or EDTA for controlling biofilm development by Listeria monocytogenes.}, journal = {Revista Argentina de microbiologia}, volume = {50}, number = {1}, pages = {48-55}, doi = {10.1016/j.ram.2017.04.011}, pmid = {28947088}, issn = {0325-7541}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteriocins/pharmacology ; *Biofilms/drug effects ; Edetic Acid ; *Lactobacillus plantarum/chemistry ; *Listeria monocytogenes/drug effects ; Propolis ; Vancomycin/pharmacology ; }, abstract = {The Listeria monocytogenes strains selected in the present study exhibited similar behavior in biofilm formation, independently of the tested conditions (bacteriocin from L. plantarum ST8SH, vancomycin, propolis (a natural antimicrobial product) and EDTA (chelating agent)), individual or in associations. The individual application of vancomycin had better inhibitory activity than that of propolis and EDTA; however, the association of the previously mentioned antimicrobial agents with bacteriocins resulted in better performance. However, when we compared the effects of vancomycin, propolis and EDTA, we could clearly observe that the combined application of bacteriocin and vancomycin was more effective than the combination of bacteriocin and propolis, and bacteriocin and EDTA. Considering the current need to reduce the use of antimicrobials and chemical substances in food processing, propolis can represent an alternative to improve the inhibitory effect of bacteriocins against L. monocytogenes biofilm formation, based on the obtained results. In general, high concentrations of bacteriocin produced by L. plantarum ST8SH were more effective in biofilm inhibition, and similar results were observed for vancomycin and propolis; however, all tested EDTA concentrations had similar effect on biofilm formation.}, } @article {pmid28946803, year = {2017}, author = {Haque, F and Sajid, M and Cameotra, SS and Battacharyya, MS}, title = {Anti-biofilm activity of a sophorolipid-amphotericin B niosomal formulation against Candida albicans.}, journal = {Biofouling}, volume = {33}, number = {9}, pages = {768-779}, doi = {10.1080/08927014.2017.1363191}, pmid = {28946803}, issn = {1029-2454}, mesh = {Amphotericin B/administration & dosage/*pharmacology ; Antifungal Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development ; Glycolipids/*chemistry ; Hyphae/drug effects/growth & development ; Liposomes ; Microbial Sensitivity Tests ; }, abstract = {Sophorolipids (SLs) have gained interest in the pharmaceutical industries due to their anti-microbial, anti-adhesive and anti-biofilm properties. In the present study, the production of SL was increased by using low-cost media components. The potential of a SL-based niosomal formulation of amphotericin B (AmB) was determined against biofilm of the opportunistic fungal pathogen Candida albicans. In-house prepared SL-AmB niosomes were characterized by different microscopic techniques. The mean entrapment efficiency of AmB within SL-AmB niosome was 63.20% ± 3.86. The cytotoxicity of SL-AmB on mature C. albicans biofilm was compared with an expensive, marketed drug, viz. phosome (a liposomal formulation of AmB). Fewer hyphae were observed in C. albicans biofilm treated with SL-AmB niosome whereas more budding cells were found in phosome treated biofilm. The present study has established the affordable production of SL and the suitability of this approach for delivery of poorly soluble drugs such as AmB against candidiasis infections.}, } @article {pmid28945343, year = {2017}, author = {Zhou, C and Wu, Y and Thappeta, KRV and Subramanian, JTL and Pranantyo, D and Kang, ET and Duan, H and Kline, K and Chan-Park, MB}, title = {In Vivo Anti-Biofilm and Anti-Bacterial Non-Leachable Coating Thermally Polymerized on Cylindrical Catheter.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {41}, pages = {36269-36280}, doi = {10.1021/acsami.7b07053}, pmid = {28945343}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Catheters ; Coated Materials, Biocompatible ; Methicillin-Resistant Staphylococcus aureus ; Mice ; Polymerization ; }, abstract = {Catheters are indispensable tools of modern medicine, but catheter-associated infection is a significant clinical problem, even when stringent sterile protocols are observed. When the bacteria colonize catheter surfaces, they tend to form biofilms making them hard to treat with conventional antibiotics. Hence, there is a great need for inherently antifouling and antibacterial catheters that prevent bacterial colonization. This paper reports the preparation of nonleachable antibiofilm and antibacterial cationic film coatings directly polymerized from actual tubular silicone catheter surfaces via the technique of supplemental activator and reducing agent surface-initiated atom-transfer radical polymerization (SARA SI-ATRP). Three cross-linked cationic coatings containing (3-acrylamidopropyl) trimethylammonium chloride (AMPTMA) or quaternized polyethylenimine methacrylate (Q-PEI-MA) together with a cross-linker (polyethylene glycol dimethacrylate, PEGDMA) were tested. The in vivo antibacterial and antibiofilm effect of these nonleachable covalently linked coatings (using a mouse catheter model) can be tuned to achieve 1.95 log (98.88%) reduction and 1.26 log (94.51%) reduction of clinically relevant pathogenic bacteria (specifically with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE)). Our good in vivo bactericidal killing results using the murine catheter-associated urinary tract infection (CAUTI) model show that SARA SI-ATRP grafting-from technique is a viable technique for making nonleachable antibiofilm coating even on "small" (0.30/0.64 mm inner/outer diameter) catheter.}, } @article {pmid28944561, year = {2017}, author = {Visvalingam, J and Ells, TC and Yang, X}, title = {Impact of persistent and nonpersistent generic Escherichia coli and Salmonella sp. recovered from a beef packing plant on biofilm formation by E. coli O157.}, journal = {Journal of applied microbiology}, volume = {123}, number = {6}, pages = {1512-1521}, doi = {10.1111/jam.13591}, pmid = {28944561}, issn = {1365-2672}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Coculture Techniques ; Escherichia coli/growth & development/isolation & purification/physiology ; Escherichia coli O157/growth & development/isolation & purification/*physiology ; *Food Handling ; Food Microbiology ; *Meat ; Salmonella/isolation & purification/*physiology ; }, abstract = {AIMS: To examine the influence of meat plant Escherichia coli and Salmonella sp. isolates on E. coli O157 biofilm formation.

METHODS AND RESULTS: Biofilm formation was quantified by crystal violet staining (A570 nm) and viable cell numbers for up to 6 days at 15°C. All five persistent E. coli genotypes formed strong biofilms when cultured alone or co-cultured with E. coli O157, with A570 nm values reaching ≥4·8 at day 4, while only two of five nonpersistent genotypes formed such biofilms. For E. coli O157:H7 co-culture biofilms with E. coli genotypes 136 and 533, its numbers were ≥1·5 and ≥1 log CFU per peg lower than those observed for its mono-culture biofilm at days 2 and 4, respectively. The number of E. coli O157:NM in similar co-culture biofilms was 1 log CFU per peg lower than in its mono-culture biofilm at day 4 and 6, respectively. Salmonella sp. lowered the number of E. coli O157:NM by 0·5 log unit, once, at day 6.

CONCLUSION: Generic E. coli may outcompete E. coli O157 strains while establishing biofilms.

Findings advance knowledge regarding inter-strain competition for a similar ecological niche and may aid development of biocontrol strategies for E. coli O157 in food processing environments.}, } @article {pmid28943153, year = {2017}, author = {Picoli, T and Peter, CM and Zani, JL and Waller, SB and Lopes, MG and Boesche, KN and Vargas, GDÁ and Hübner, SO and Fischer, G}, title = {Melittin and its potential in the destruction and inhibition of the biofilm formation by Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa isolated from bovine milk.}, journal = {Microbial pathogenesis}, volume = {112}, number = {}, pages = {57-62}, doi = {10.1016/j.micpath.2017.09.046}, pmid = {28943153}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bee Venoms/pharmacology ; Biofilms/*drug effects/growth & development ; Cattle ; Escherichia coli/*drug effects/isolation & purification ; Gram-Negative Bacteria/drug effects ; Melitten/*pharmacology ; Microbial Sensitivity Tests ; Milk/*microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification ; Staphylococcus aureus/*drug effects/isolation & purification ; }, abstract = {Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa stand out in veterinary and human medicine for their role in opportunistic infections and their pathogenic mechanisms, including the biofilms formation. It was investigated the antibacterial activity of melittin and antibiofilm of such bacteria. Twelve strains of these microorganisms isolated from bovine milk were used, as well as the strains S. aureus ATCC 12600, E. coli ATCC 8739 and Pseudomonas aeruginosa ATCC 15442. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution technique. The biofilms were formed in 96-well plates and melittin on these colonies was added at different concentrations and times. Bacteria previously exposed to melittin were evaluated for inhibition of biofilm production. The MIC and MBC were respectively in μg/mL: S. aureus (6-7 and 32-64), E. coli (40-42.5 and 64-128) and P. aeruginosa (65-70 and 64-128). S. aureus biofilms were more sensitive to the action of melittin, since upon exposure to a concentration 10 times lower than the MIC for 4 h, was completely destroyed. In Gram negative bacteria, the pre-formed biofilm was destroyed only when exposed for 4 h under the MIC. With respect to inhibition of biofilm production, S. aureus was the most sensitive again because produced only 37.2% of the biofilm formed by the control (without previous exposure to melittin), when exposed to the MIC, and at a concentration hundred times smaller than MIC, this microorganism produced 75.2% of the biofilm. E. coli was the most resistant bacteria and produced 56.3% of the biofilm, even if previously exposed to melittin MIC. Melittin presents desirable effects in combating microorganisms studied both at your disposal, biofilm destruction and inhibition of the formation, and maybe used in future studies of new strategies to combat infections caused by these pathogens.}, } @article {pmid28942495, year = {2018}, author = {Tejima, K and Ishiai, M and Murayama, SO and Iwatani, S and Kajiwara, S}, title = {Candida albicans fatty acyl-CoA synthetase, CaFaa4p, is involved in the uptake of exogenous long-chain fatty acids and cell activity in the biofilm.}, journal = {Current genetics}, volume = {64}, number = {2}, pages = {429-441}, pmid = {28942495}, issn = {1432-0983}, mesh = {Acyl Coenzyme A/*genetics ; Biofilms/growth & development ; Biological Transport/genetics ; Candida albicans/*genetics/growth & development ; Cerulenin/pharmacology ; Coenzyme A Ligases/*genetics ; Fatty Acids/*genetics/metabolism ; Mutation ; Saccharomyces cerevisiae/genetics/growth & development ; Saccharomyces cerevisiae Proteins/*genetics ; Sequence Homology, Amino Acid ; }, abstract = {Fatty acyl-CoA synthetase (Faa) activates fatty acid (FA) by converting the FA into the CoA ester in the cell. In the present study, we characterized a FAA homologue (CaFAA4) from the opportunistic pathogen Candida albicans. Most organisms can not only synthesize long-chain fatty acyl-CoAs (LCFA-CoAs) endogenously using a fatty acid synthase (Fas) activity but also can uptake long-chain fatty acids (LCFAs) from the extracellular environment and convert them into LCFA-CoAs via a vectorial acylation system. The budding yeast Saccharomyces cerevisiae possesses two LCFA-CoA synthetases, ScFaa1p and ScFaa4p. The disruption of ScFAA1 and ScFAA4 leads to synthetic lethality in the presence of a fatty acid synthesis inhibitor-cerulenin. The homologue-CaFAA4-rescued the lethality of an S. cerevisiae Scfaa1-Scfaa4 double mutant in the presence of cerulenin. On the other hand, a C. albicans faa4 mutant was unable to grow in the presence of cerulenin even if LCFAs were provided exogenously. Moreover, a biofilm analysis showed that the metabolic activity of the Cafaa4 mutant was approximately 40% lower than that of the wild-type parent, even though there was no significant difference in cell number or cell morphology between these strains. Notably, the Cafaa4 mutant showed increased susceptibility to micafungin during biofilm formation, a phenotype that presumably can be attributed to the impaired metabolism of the mutant strain. These results indicated that CaFaa4p is the unique C. albicans Faa protein responsible for activating LCFAs and is involved in the metabolism of biofilms.}, } @article {pmid28942174, year = {2017}, author = {Srivastava, A and Gupta, J and Kumar, S and Kumar, A}, title = {Gut biofilm forming bacteria in inflammatory bowel disease.}, journal = {Microbial pathogenesis}, volume = {112}, number = {}, pages = {5-14}, doi = {10.1016/j.micpath.2017.09.041}, pmid = {28942174}, issn = {1096-1208}, mesh = {Anti-Inflammatory Agents/pharmacology ; Bacteria/drug effects/*immunology/pathogenicity ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives ; Dysbiosis ; Gastrointestinal Microbiome/*immunology ; Gastrointestinal Tract/*immunology/*microbiology ; Humans ; Immunosuppressive Agents/pharmacology ; Inflammation/*immunology ; Inflammatory Bowel Diseases/diagnosis/drug therapy/*immunology/*microbiology ; Intestinal Mucosa/immunology/microbiology ; Intestines/immunology/microbiology ; Quorum Sensing ; Stomach/microbiology ; }, abstract = {Inflammatory bowel disease (IBD) symbolizes a group of intestinal disorders in which prolonged inflammation occur in the digestive tract (esophagus, large intestine, small intestine mouth, stomach). Both genetic and environmental factors (infections, stress, diet) are involved in the development of IBD. As we know that bacteria are found in the intestinal mucosa of human and clinical observations revealed bacterial biofilms associated with patients of IBD. Various factors and microbes are found to play an essential role in biofilm formation and mucosal colonization during IBD. Biofilm formation in the digestive tract is dependent on an extracellular matrix synthesized by the bacteria and it has an adverse effect on the immune response of the host. There is no satisfactory and safe treatment option for IBD. Therefore, the current research aims to disrupt biofilm in IBD and concentrates predominantly on improving the drug. Here, we review the literature on bacterial biofilm and IBD to gather new knowledge on the current understanding of biofilm formation in IBD, host immune deregulation and dysbiosis in IBD, molecular mechanism, bacteria involved in biofilm formation, current and future regimen. It is urgently required to plan new ways to control and eradicate bacteria in biofilms that will open up novel diagnostic and therapeutic avenues for IBD. This article includes the mechanism of signaling molecules with respect to the biofilm-related genes as well as the diagnostic methods and new technologies involved in the treatment of IBD.}, } @article {pmid28941889, year = {2018}, author = {Klein, MN and Kupper, KC}, title = {Biofilm production by Aureobasidium pullulans improves biocontrol against sour rot in citrus.}, journal = {Food microbiology}, volume = {69}, number = {}, pages = {1-10}, doi = {10.1016/j.fm.2017.07.008}, pmid = {28941889}, issn = {1095-9998}, mesh = {Antibiosis ; Ascomycota/*physiology ; *Biofilms ; Citrus/*microbiology ; Geotrichum/growth & development/pathogenicity/*physiology ; Hyphae/growth & development/pathogenicity/physiology ; Plant Diseases/*microbiology/prevention & control ; Virulence ; }, abstract = {The biocontrol efficiency of Aureobasidium pullulans strain ACBL-77 against Geotrichum citri-aurantii, causal agent of sour rot in citrus, and their interactions were evaluated. For this, were evaluated the incorporation of nutrients in optimizing the antagonistic activity of the yeast, the competition for nutrients between microorganisms, the effect of nutrients on yeast cell and biofilm production and their correlation in the biocontrol of disease, the survival of yeast in citrus fruits and the interaction between microorganisms using scanning electron microscopy. Micronutrients (boric acid, cobalt chloride and ammonium molybdate) favoured the antagonistic action of A. pullulans. Ammonium sulfate 1% and sucrose 0.5% favoured the yeast during the competition between the microorganisms. The addition of ammonium sulfate (1%) in the yeast culture stimulated biofilm production and increased the antagonistic activity against the disease, as also allowed the better survival of yeast in wounded sites of citrus fruit. The yeast was found to be able to form biofilms on citrus, deforming the pathogen hyphae. These results showed the importance of the addition of nutrients in A. pullulans based-formulations when aiming for their use on a commercial scale. This is the first report of a positive correlation between the increase in the quantity of biofilm produced by A. pullulans, with increased antagonistic activity.}, } @article {pmid28939900, year = {2017}, author = {Nzakizwanayo, J and Scavone, P and Jamshidi, S and Hawthorne, JA and Pelling, H and Dedi, C and Salvage, JP and Hind, CK and Guppy, FM and Barnes, LM and Patel, BA and Rahman, KM and Sutton, MJ and Jones, BV}, title = {Fluoxetine and thioridazine inhibit efflux and attenuate crystalline biofilm formation by Proteus mirabilis.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {12222}, pmid = {28939900}, issn = {2045-2322}, support = {MR/N006496/1/MRC_/Medical Research Council/United Kingdom ; R394/1114/DMT_/The Dunhill Medical Trust/United Kingdom ; }, mesh = {Bacterial Proteins/antagonists & inhibitors/chemistry/metabolism ; Biofilms/drug effects ; Catheter-Related Infections/microbiology/*prevention & control ; Catheters, Indwelling/adverse effects/microbiology ; Drug Repositioning ; Fluoxetine/chemistry/*pharmacology ; Humans ; Membrane Transport Proteins/chemistry/metabolism ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Proteus Infections/microbiology/*prevention & control ; Proteus mirabilis/*drug effects/physiology ; Thioridazine/chemistry/*pharmacology ; Urinary Catheterization/adverse effects/instrumentation ; Urinary Catheters/adverse effects/microbiology ; }, abstract = {Proteus mirabilis forms extensive crystalline biofilms on indwelling urethral catheters that block urine flow and lead to serious clinical complications. The Bcr/CflA efflux system has previously been identified as important for development of P. mirabilis crystalline biofilms, highlighting the potential for efflux pump inhibitors (EPIs) to control catheter blockage. Here we evaluate the potential for drugs already used in human medicine (fluoxetine and thioridazine) to act as EPIs in P. mirabilis, and control crystalline biofilm formation. Both fluoxetine and thioridazine inhibited efflux in P. mirabilis, and molecular modelling predicted both drugs interact strongly with the biofilm-associated Bcr/CflA efflux system. Both EPIs were also found to significantly reduce the rate of P. mirabilis crystalline biofilm formation on catheters, and increase the time taken for catheters to block. Swimming and swarming motilies in P. mirabilis were also significantly reduced by both EPIs. The impact of these drugs on catheter biofilm formation by other uropathogens (Escherichia coli, Pseudomonas aeruginosa) was also explored, and thioridazine was shown to also inhibit biofilm formation in these species. Therefore, repurposing of existing drugs with EPI activity could be a promising approach to control catheter blockage, or biofilm formation on other medical devices.}, } @article {pmid28934980, year = {2017}, author = {Ster, C and Lebeau, V and Leclerc, J and Fugère, A and Veh, KA and Roy, JP and Malouin, F}, title = {In vitro antibiotic susceptibility and biofilm production of Staphylococcus aureus isolates recovered from bovine intramammary infections that persisted or not following extended therapies with cephapirin, pirlimycin or ceftiofur.}, journal = {Veterinary research}, volume = {48}, number = {1}, pages = {56}, pmid = {28934980}, issn = {1297-9716}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Breast Diseases/drug therapy/microbiology/*veterinary ; Cattle ; Cattle Diseases/drug therapy/*microbiology ; Cephalosporins/*therapeutic use ; Cephapirin/*therapeutic use ; Clindamycin/*analogs & derivatives/therapeutic use ; Drug Resistance, Bacterial/genetics ; Female ; Microbial Sensitivity Tests/veterinary ; Minisatellite Repeats/genetics ; Staphylococcal Infections/drug therapy/microbiology/*veterinary ; Staphylococcus aureus/*drug effects/genetics ; }, abstract = {Staphylococcus aureus intramammary infections (IMIs) have low cure rates using standard antibiotic treatment and increasing the duration of treatment usually improves therapeutic success. Chronic IMIs are thought to be caused by bacteria presenting a specific virulence phenotype that includes the capacity to produce greater amounts of biofilm. In this study, antibiotic susceptibility and biofilm production by S. aureus isolates recovered from IMIs that were cured or not following an extended therapy with cephapirin, pirlimycin or ceftiofur for 5, 8 and 8 days, respectively, were compared. An isolate was confirmed as from a persistent case (not cured) if the same S. aureus strain was isolated before and after treatment as revealed by the same VNTR profile (variable number of tandem repeats detected by multiplex PCR). The antibiotic minimal inhibitory concentrations (MICs) were determined for these isolates as well as the capacity of the isolates to produce biofilm. Isolates from persistent cases after extended therapy with cephapirin or ceftiofur had higher MICs for these drugs compared to isolates from non-persistent cases (p < 0.05) even though the antibiotic susceptibility breakpoints were not exceeded. Isolates of the ceftiofur study significantly increased their biofilm production in presence of a sub-MIC of ceftiofur (p < 0.05), whereas isolates from the pirlimycin group produced significantly less biofilm in presence of a sub-MIC of pirlimycin (p < 0.001). Relative antibiotic susceptibility of the isolates as well as biofilm production may play a role in the failure of extended therapies. On the other hand, some antibiotics may counteract biofilm formation and improve cure rates.}, } @article {pmid28932816, year = {2017}, author = {Junges, R and Salvadori, G and Shekhar, S and Åmdal, HA and Periselneris, JN and Chen, T and Brown, JS and Petersen, FC}, title = {A Quorum-Sensing System That Regulates Streptococcus pneumoniae Biofilm Formation and Surface Polysaccharide Production.}, journal = {mSphere}, volume = {2}, number = {5}, pages = {}, pmid = {28932816}, issn = {2379-5042}, support = {MR/K00168X/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {Despite vaccines, Streptococcus pneumoniae kills more than a million people yearly. Thus, understanding how pneumococci transition from commensals to pathogens is particularly relevant. Quorum sensing regulates collective behaviors and thus represents a potential driver of commensal-to-pathogen transitions. Rgg/small hydrophobic peptide (SHP) quorum-sensing systems are widespread in streptococci, yet they remain largely uncharacterized in S. pneumoniae. Using directional transcriptome sequencing, we show that the S. pneumoniae D39 Rgg0939/SHP system induces the transcription of a single gene cluster including shp and capsule gene homologs. Capsule size measurements determined by fluorescein isothiocyanate-dextran exclusion allowed assignment of the system to the regulation of surface polysaccharide expression. We found that the SHP pheromone induced exopolysaccharide expression in R36A, an unencapsulated derivative of D39. In the encapsulated parent strain, overexpression of the Rgg system resulted in a mutant with increased capsule size. In line with previous studies showing that capsule expression is inversely associated with biofilm formation, we found that biofilm formed on lung epithelial cells was decreased in the overexpression strain and increased in an rgg deletion mutant. Although no significant differences were observed between D39 and the rgg deletion mutant in a mouse model of lung infection, in competitive assays, overexpression reduced fitness. This is the first study to reveal a quorum-sensing system in streptococci that regulates exopolysaccharide synthesis from a site distinct from the original capsule locus. IMPORTANCE Quorum sensing regulates bacterial social behaviors by production, secretion, and sensing of pheromones. In this study, we characterized a new quorum-sensing system of the Rgg/SHP class in S. pneumoniae D39. The system was found to directly induce the expression of a single gene cluster comprising the gene for the SHP pheromone and genes with putative functions in capsule synthesis. Capsule size, as measured by dextran exclusion, was increased by SHP exposure in R36A, an unencapsulated derivative of D39. In the encapsulated parent strain, overexpression of the gene cluster increased capsule size, supporting the role of Rgg/SHP in the synthesis of surface polysaccharides. Further, we found that biofilm formation on epithelial cells was reduced by overexpression of the system and increased in a mutant with an rgg deletion. Placing surface polysaccharide expression under quorum-sensing regulation may enable S. pneumoniae to tune interactions with the host and other bacteria in accordance with environmental and cell density conditions.}, } @article {pmid28931414, year = {2017}, author = {Sharma, V and Sharma, S and Dahiya, DK and Khan, A and Mathur, M and Sharma, A}, title = {Coagulase gene polymorphism, enterotoxigenecity, biofilm production, and antibiotic resistance in Staphylococcus aureus isolated from bovine raw milk in North West India.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {16}, number = {1}, pages = {65}, pmid = {28931414}, issn = {1476-0711}, mesh = {Adhesins, Bacterial/genetics ; Animals ; Anti-Bacterial Agents/pharmacology ; Base Sequence ; Biofilms/*growth & development ; Cattle ; Cattle Diseases/microbiology ; Coagulase/*genetics ; DNA, Bacterial ; Drug Resistance, Microbial/*genetics ; Enterotoxins/biosynthesis/*genetics ; Food Microbiology ; Genes, Bacterial/genetics ; Genetic Heterogeneity ; Genotype ; Geographic Mapping ; Humans ; India ; Methicillin-Resistant Staphylococcus aureus/genetics ; Microbial Sensitivity Tests ; Milk/*microbiology ; Polymorphism, Genetic/*genetics ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/*genetics/isolation & purification/*metabolism ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Staphylococcus aureus is the predominant bacterium responsible for various diseases in animals and humans. Preventive strategies could be better implemented by understanding the prevalence, genetic patterns, and the presence of enterotoxin and biofilm-producing genes along with the antibiotic susceptibility of this organism. This study was conducted in Rajasthan, the northwestern state of India, holding the largest population of cattle that makes it the second largest milk producer in India and no such prior information is available on these aspects.

METHODS: A total of 368 individual quarter bovine raw milk samples were collected from 13 districts of Rajasthan, and screened for the presence of S. aureus. Microbiological and molecular approaches were followed for bacterial identification. Genetic diversity was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of coagulase gene (coa), whereas enterotoxin and biofilm-producing genes were studied by PCR analysis. Antibiotic strips were employed to study the antibiotic resistance among strains.

RESULTS: In all, 73 S. aureus strains were obtained from 368 bovine raw milk samples out of that only 30 showed the presence of coa. Nine types of coa patterns ranging from 730 to 1130 bp were observed among these isolates. PCR-RFLP of coa distinguished the isolates into 15 genotypic patterns, of which patterns I, IV, V, and VI were predominant. Of the isolates, 30% were positive for sec, 10% for sea, and 3.3% for seb; these genes are responsible for enterotoxin production, whereas all isolates were found positive for icaAD and eno. The prevalence rates of other biofilm-producing genes fnbA, clfB, ebpS, sasG, fnbB, sasC, cna, bap, fib and, bbp were 97, 93, 90, 80, 80, 77, 53, 27, 10, and 6.6%, respectively. Twenty-seven (90%) strains were multidrug resistant, of which 15 were methicillin resistant. Maximum sensitivity was reported for kanamycin and it could be considered as a drug of choice for controlling S. aureus mediated cattle infections in the studied regions.

CONCLUSIONS: Overall, these strains could cause several diseases to humans, insisting the need for developing a stricter hygiene program for improving milking practices and animal health.}, } @article {pmid28931205, year = {2017}, author = {Mohottige, TNW and Ginige, MP and Kaksonen, AH and Sarukkalige, R and Cheng, KY}, title = {Bioelectrochemical oxidation of organics by alkali-halotolerant anodophilic biofilm under nitrogen-deficient, alkaline and saline conditions.}, journal = {Bioresource technology}, volume = {245}, number = {Pt A}, pages = {890-898}, doi = {10.1016/j.biortech.2017.08.157}, pmid = {28931205}, issn = {1873-2976}, mesh = {Alkalies ; *Biofilms ; *Bioreactors ; Nitrogen ; Sewage ; }, abstract = {This work aimed to study the feasibility of using bioelectrochemical systems (BES) for organics removal under alkaline-saline and nitrogen (N) deficient conditions. Two BES inoculated with activated sludge were examined for organics (oxalate, acetate, formate) oxidation under alkaline-saline (pH 9.5, 25g/L NaCl) and N deficient conditions. One reactor (R1) received ammonium chloride as an N-source, while the other (R2) without. The reactors were initially loaded with only oxalate (25mM), but start-up was achieved only when acetate was added as co-substrate (5mM). Maximum current were R1: 908A/m[3] (organic removal rate (ORR) 4.61kgCOD/m[3]·d) and R2: 540A/m[3] (ORR 2.06kgCOD/m[3]·d). Formate was utilised by both anodic biofilms, but the inefficient oxalate removal was likely due to the paucity of microorganisms that catalyse decarboxylation of oxalate into formate. Further development of this promising technology for the treatment of alkaline-saline wastewater is warranted.}, } @article {pmid28929959, year = {2017}, author = {Öcal, DN and Dolapçı, İ and Gençtürk, Z and Tekeli, A}, title = {[In vitro effect of vancomycin and daptomycin on biofilm formation of coagulase-negative staphylococci strains].}, journal = {Mikrobiyoloji bulteni}, volume = {51}, number = {3}, pages = {220-235}, doi = {10.5578/mb.57435}, pmid = {28929959}, issn = {0374-9096}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteremia/drug therapy/microbiology/mortality ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections/drug therapy/microbiology/mortality ; Daptomycin/*pharmacology ; Humans ; Methicillin Resistance ; Microbial Sensitivity Tests ; Morbidity ; Staphylococcal Infections/drug therapy/microbiology/mortality ; Staphylococcus/classification/drug effects/genetics/*physiology ; Turkey ; Vancomycin/*pharmacology ; }, abstract = {Coagulase-negative staphylococci (CNS) are one of the primer agents of blood stream infections (BSI) and catheter-related bloodstream infections (CR-BSI) which are associated mostly with the usage of central venous catheters and, important causes of morbidity and mortality despite the usage of antibacterial and supportive treatment. It is important to determine the properties of these causative microorganisms in order to make appropriate treatment of such infections. The aims of our study were to evaluate the biofilm formation of coagulase negative staphylococci (CNS) which were causative agents of bloodstream (BSI) and catheter related bloodstream infections (CR-BSI), to determine the minimum inhibitory concentration (MIC) of planktonic forms and minimal biofilm eradication concentration (MBEC) of sessile forms for vancomycin and daptomycin and to evaluate the efficacy of these antibiotics in infections with biofilm-forming isolates in vitro. A total of 65 CoNS (n= 26 catheter colonizers, n= 28 CR-BSI, n= 11 BSI agents) were identified by conventional methods and also with BD Phoenix (Becton Dickinson, USA) and Bruker Microflex MS (Bruker Daltonics, Germany) systems. Methicillin resistance was determined by the presence of mecA gene with PCR. MIC values of vancomycin and daptomycin were investigated by broth microdilution, for daptomycin medium containing 25 and 50 μg/ml Ca++ were used. Assessment of biofilm formation and detection of MBEC were determined by microplate method. The clonal relationship was investigated by the PFGE method. A total of 65 isolates; 26 catheter colonizers, 28 CR-BSI agents and 11 BSI agents were evaluated and identified as Staphylococcus epidermidis (n= 33), Staphylococcus haemolyticus (n= 16), Staphylococcus hominis (n= 15), and Staphylococcus capitis (n= 1). 81.5% of the isolates were found to be methicillin resistant and all of them were found to be sensitive to vancomycin (MIC= 0.125-4 μg/ml) and daptomycin (MIC= 0.062-0.25 μg/ml in 25 μg/ml Ca++ and MIC= 0.031-0.50 μg/ml in 50 μg/ml Ca++ containing medium). MIC values were lower in medium containing 50 μg/ml Ca++ for daptomycin. As it is known that the efficacy of daptomycin depends on the physiological levels of Ca++, which causes conformational changes in the structure of these antibacterials. Our findings also suggested that high levels of Ca++ are needed to ensure the efficacy of daptomycin. All of the isolates produced biofilm at different strengths of positivity (n= 12/18.5% weak, n= 35/%53.8 moderate, n= 18/%27.7 strong). MBEC and MBEC/MIC values for vancomycin were found to be higher than daptomycin (p< 0.001). Strong biofilm producers had higher MBEC and MBEC/MIC, MBEC50/MIC50 ve MBEC90/MIC90 values (p< 0.05). Especially in infections with biofilm forming isolates, the detection of only MIC values are not always sufficient in the treatment of biofilm-related infections as they reflect the sensitivity of planktonic bacteria. The inconsistency between the MIC and MBEC values and the high rates of MBEC/MIC found in our study supported this prediction.The lower detection of MBEC and MBEC/MIC values of daptomycin compared to the same values of vancomycin suggested that daptomycin might be effective at lower doses than vancomycin in the treatment of biofilm infections.}, } @article {pmid28928729, year = {2017}, author = {Kang, D and Kirienko, NV}, title = {High-Throughput Genetic Screen Reveals that Early Attachment and Biofilm Formation Are Necessary for Full Pyoverdine Production by Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1707}, pmid = {28928729}, issn = {1664-302X}, support = {K22 AI110552/AI/NIAID NIH HHS/United States ; }, abstract = {Pseudomonas aeruginosa is a re-emerging, multidrug-resistant, opportunistic pathogen that threatens the lives of immunocompromised patients, patients with cystic fibrosis, and those in critical care units. One of the most important virulence factors in this pathogen is the siderophore pyoverdine. Pyoverdine serves several critical roles during infection. Due to its extremely high affinity for ferric iron, pyoverdine gives the pathogen a significant advantage over the host in their competition for iron. In addition, pyoverdine can regulate the production of multiple bacterial virulence factors and perturb host mitochondrial homeostasis. Inhibition of pyoverdine biosynthesis decreases P. aeruginosa pathogenicity in multiple host models. To better understand the regulation of pyoverdine production, we developed a high-throughput genetic screen that uses the innate fluorescence of pyoverdine to identify genes necessary for its biosynthesis. A substantial number of hits showing severe impairment of pyoverdine production were in genes responsible for early attachment and biofilm formation. In addition to genetic disruption of biofilm, both physical and chemical perturbations also attenuated pyoverdine production. This regulatory relationship between pyoverdine and biofilm is particularly significant in the context of P. aeruginosa multidrug resistance, where the formation of biofilm is a key mechanism preventing access to antimicrobials and the immune system. Furthermore, we demonstrate that the biofilm inhibitor 2-amino-5,6-dimethylbenzimidazole effectively attenuates pyoverdine production and rescues Caenorhabditis elegans from P. aeruginosa-mediated pathogenesis. Our findings suggest that targeting biofilm formation in P. aeruginosa infections may have multiple therapeutic benefits and that employing an unbiased, systems biology-based approach may be useful for understanding the regulation of specific virulence factors and identifying novel anti-virulence therapeutics or new applications for existing therapies for P. aeruginosa infections.}, } @article {pmid28928721, year = {2017}, author = {Al-Yousef, HM and Ahmed, AF and Al-Shabib, NA and Laeeq, S and Khan, RA and Rehman, MT and Alsalme, A and Al-Ajmi, MF and Khan, MS and Husain, FM}, title = {Onion Peel Ethylacetate Fraction and Its Derived Constituent Quercetin 4'-O-β-D Glucopyranoside Attenuates Quorum Sensing Regulated Virulence and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1675}, pmid = {28928721}, issn = {1664-302X}, abstract = {The resistance and pathogenesis of bacteria could be related to their ability to sense and respond to population density, termed quorum sensing (QS). Inhibition of the QS system is considered as a novel strategy for the development of antipathogenic agents, especially for combating drug-resistant bacterial infections. In the present study, the anti-QS activity of Onion peel ethylacetate fraction (ONE) was tested against Chromobacterium violaceum CV12472 and Pseudomonas aeruginosa PAO1. ONE inhibit the QS-mediated virulence factors production such as violacein in C. violaceum and elastase, pyocyanin in P. aeruginosa. Further, the treatment with sub-MICs of ONE significantly inhibited the QS-mediated biofilm formation, EPS (Extracellular polymeric substances) production and swarming motility. Further, quercetin 4'-O-β-D glucopyranoside (QGP) was isolated from ONE and its anti-QS potential was confirmed after observing significant inhibition of QS-controlled virulence factors such as violacein, elastase, pyocyanin and biofilm formation in test pathogens. Molecular docking analysis predicted that QGP should be able to bind at the active sites of Vfr and LasR, and if so blocks the entry of active sites in Vfr and LasR.}, } @article {pmid28928205, year = {2017}, author = {Moreira, RN and Dressaire, C and Barahona, S and Galego, L and Kaever, V and Jenal, U and Arraiano, CM}, title = {BolA Is Required for the Accurate Regulation of c-di-GMP, a Central Player in Biofilm Formation.}, journal = {mBio}, volume = {8}, number = {5}, pages = {}, pmid = {28928205}, issn = {2150-7511}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli/*genetics ; Escherichia coli Proteins/genetics/*metabolism ; *Gene Expression Regulation, Bacterial ; Phosphoric Diester Hydrolases/genetics/metabolism ; Second Messenger Systems ; Signal Transduction ; Transcription Factors/genetics/*metabolism ; }, abstract = {The bacterial second messenger cyclic dimeric GMP (c-di-GMP) is a nearly ubiquitous intracellular signaling molecule involved in the transition from the motile to the sessile/biofilm state in bacteria. C-di-GMP regulates various cellular processes, including biofilm formation, motility, and virulence. BolA is a transcription factor that promotes survival in different stresses and is also involved in biofilm formation. Both BolA and c-di-GMP participate in the regulation of motility mechanisms leading to similar phenotypes. Here, we establish the importance of the balance between these two factors for accurate regulation of the transition between the planktonic and sessile lifestyles. This balance is achieved by negative-feedback regulation of BolA and c-di-GMP. BolA not only contributes directly to the motility of bacteria but also regulates the expression of diguanylate cyclases and phosphodiesterases. This expression modulation influences the synthesis and degradation of c-di-GMP, while this signaling metabolite has a negative influence in bolA mRNA transcription. Finally, we present evidence of the dominant role of BolA in biofilm, showing that, even in the presence of elevated c-di-GMP levels, biofilm formation is reduced in the absence of BolA. C-di-GMP is one of the most important bacterial second messengers involved in several cellular processes, including virulence, cell cycle regulation, biofilm formation, and flagellar synthesis. In this study, we unravelled a direct connection between the bolA morphogene and the c-di-GMP signaling molecule. We show the important cross-talk that occurs between these two molecular regulators during the transition between the motile/planktonic and adhesive/sessile lifestyles in Escherichia coli This work provides important clues that can be helpful in the development of new strategies, and the results can be applied to other organisms with relevance for human health.IMPORTANCE Bacterial cells have evolved several mechanisms to cope with environmental stresses. BolA-like proteins are widely conserved from prokaryotes to eukaryotes, and in Escherichia coli, in addition to its pleiotropic effects, this protein plays a determinant role in bacterial motility and biofilm formation regulation. Similarly, the bacterial second messenger c-di-GMP is a molecule with high importance in coordinating the switch between planktonic and sessile life in bacteria. Here we have unravelled the importance of accurate regulation of cross-talk between BolA and c-di-GMP for a proper response in the regulation of these bacterial lifestyles. This finding underlines the complexity of bacterial cell regulation, revealing the existence of one additional tool for fine-tuning such important cellular molecular mechanisms. The relationship between BolA and c-di-GMP gives new perspectives regarding biofilm formation and opens the possibility to extend our studies to other organisms with relevance for human health.}, } @article {pmid28926554, year = {2017}, author = {Papenfort, K and Silpe, JE and Schramma, KR and Cong, JP and Seyedsayamdost, MR and Bassler, BL}, title = {Erratum: A Vibrio cholerae autoinducer-receptor pair that controls biofilm formation.}, journal = {Nature chemical biology}, volume = {13}, number = {10}, pages = {1137}, pmid = {28926554}, issn = {1552-4469}, } @article {pmid28926148, year = {2017}, author = {Feng, K and Zhang, Z and Cai, W and Liu, W and Xu, M and Yin, H and Wang, A and He, Z and Deng, Y}, title = {Biodiversity and species competition regulate the resilience of microbial biofilm community.}, journal = {Molecular ecology}, volume = {26}, number = {21}, pages = {6170-6182}, doi = {10.1111/mec.14356}, pmid = {28926148}, issn = {1365-294X}, mesh = {Bacteria/*classification ; *Biodiversity ; Bioelectric Energy Sources ; *Biofilms ; Bioreactors/microbiology ; Hydrogen-Ion Concentration ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The relationship between biodiversity and ecosystem stability is poorly understood in microbial communities. Biofilm communities in small bioreactors called microbial electrolysis cells (MEC) contain moderate species numbers and easy tractable functional traits, thus providing an ideal platform for verifying ecological theories in microbial ecosystems. Here, we investigated the resilience of biofilm communities with a gradient of diversity, and explored the relationship between biodiversity and stability in response to a pH shock. The results showed that all bioreactors could recover to stable performance after pH disturbance, exhibiting a great resilience ability. A further analysis of microbial composition showed that the rebound of Geobacter and other exoelectrogens contributed to the resilient effectiveness, and that the presence of Methanobrevibacter might delay the functional recovery of biofilms. The microbial communities with higher diversity tended to be recovered faster, implying biofilms with high biodiversity showed better resilience in response to environmental disturbance. Network analysis revealed that the negative interactions between the two dominant genera of Geobacter and Methanobrevibacter increased when the recovery time became longer, implying the internal resource or spatial competition of key functional taxa might fundamentally impact the resilience performances of biofilm communities. This study provides new insights into our understanding of the relationship between diversity and ecosystem functioning.}, } @article {pmid28925553, year = {2017}, author = {Poosarla, VG and Wood, TL and Zhu, L and Miller, DS and Yin, B and Wood, TK}, title = {Dispersal and inhibitory roles of mannose, 2-deoxy-d-glucose and N-acetylgalactosaminidase on the biofilm of Desulfovibrio vulgaris.}, journal = {Environmental microbiology reports}, volume = {9}, number = {6}, pages = {779-787}, doi = {10.1111/1758-2229.12595}, pmid = {28925553}, issn = {1758-2229}, mesh = {Acetylgalactosamine/metabolism ; Acetylglucosaminidase/*pharmacology ; Antimetabolites/pharmacology ; Biofilms/*drug effects ; Deoxyglucose/*pharmacology ; Desulfovibrio desulfuricans/drug effects/physiology ; Desulfovibrio vulgaris/*drug effects/genetics/physiology ; Mannose/analogs & derivatives/*pharmacology ; Polysaccharides, Bacterial/chemistry/genetics/metabolism ; Staining and Labeling ; }, abstract = {Biofilms of sulfate-reducing bacteria (SRB) are often the major cause of microbiologically influenced corrosion. The representative SRB Desulfovibrio vulgaris has previously been shown to have a biofilm that consists primarily of protein. In this study, by utilizing lectin staining, we identified that the biofilm of D. vulgaris also consists of the matrix components mannose, fucose and N-acetylgalactosamine (GalNAc), with mannose predominating. Based on these results, we found that the addition of mannose and the nonmetabolizable mannose analog 2-deoxy-d-glucose inhibits the biofilm formation of D. vulgaris as well as that of D. desulfuricans; both compounds also dispersed the SRB biofilms. In addition, the enzyme N-acetylgalactosaminidase, which degrades GalNAc, was effective in dispersing D. vulgaris biofilms. Therefore, by determining composition of the SRB biofilm, effective biofilm control methods may be devised.}, } @article {pmid28923875, year = {2017}, author = {Maura, D and Rahme, LG}, title = {Pharmacological Inhibition of the Pseudomonas aeruginosa MvfR Quorum-Sensing System Interferes with Biofilm Formation and Potentiates Antibiotic-Mediated Biofilm Disruption.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {12}, pages = {}, pmid = {28923875}, issn = {1098-6596}, support = {R33 AI105902/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*antagonists & inhibitors/genetics/metabolism ; Benzamides/chemical synthesis/pharmacology ; Benzimidazoles/chemical synthesis/pharmacology ; Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Culture Media/chemistry ; Drug Synergism ; Drug Tolerance/genetics ; *Gene Expression Regulation, Bacterial ; Meropenem ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development ; Quorum Sensing/*drug effects ; Thienamycins/pharmacology ; Tobramycin/pharmacology ; Transcription, Genetic ; }, abstract = {Pseudomonas aeruginosa biofilms contribute to its survival on biotic and abiotic surfaces and represent a major clinical threat due to their high tolerance to antibiotics. Therefore, the discovery of antibiofilm agents may hold great promise. We show that pharmacological inhibition of the P. aeruginosa quorum-sensing regulator MvfR (PqsR) using a benzamide-benzimidazole compound interferes with biofilm formation and potentiates biofilm sensitivity to antibiotics. Such a strategy could have great potential against P. aeruginosa persistence in diverse environments.}, } @article {pmid28922635, year = {2017}, author = {S, E and T R, N and V K, R and Baranwal, G and Biswas, R and R, J and S, S}, title = {Fucoidan coated ciprofloxacin loaded chitosan nanoparticles for the treatment of intracellular and biofilm infections of Salmonella.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {160}, number = {}, pages = {40-47}, doi = {10.1016/j.colsurfb.2017.09.003}, pmid = {28922635}, issn = {1873-4367}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Chitosan/*chemistry ; Ciprofloxacin/administration & dosage/chemistry/*pharmacology ; Drosophila melanogaster/microbiology ; Drug Delivery Systems/methods ; Female ; Humans ; Male ; Mice ; Microscopy, Electron ; Nanoparticles/*chemistry/ultrastructure ; Polysaccharides/*chemistry ; RAW 264.7 Cells ; Salmonella/*drug effects/physiology ; Salmonella Infections/drug therapy/microbiology ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Salmonella infections and their gallstone associated biofilm infections are difficult to treat due to poor penetration of antibiotics into the intracellular compartments of macrophages and within biofilms. Here we developed ciprofloxacin loaded chitosan nanoparticles (cCNPs) and fucoidan (Fu) coated cCNPs (Fu-cCNPs). Characterizations of these nanoparticles were carried out using Dynamic Light Scattering‎, Transmission electron microscopy and Fourier transform infrared spectroscopy. The prepared cCNPs and Fu-cCNPs have the size range of 124±7nm and 320±18nm, respectively. Both nanoparticles were found to be non-hemolytic and cytocompatible. In vitro sustained release of ciprofloxacin was observed from both cCNPs and Fu-cCNPs over a period of 2 weeks. The antimicrobial activity of cCNPs and Fu-cCNPs was tested under in vitro and in vivo conditions. The intracellular anti-Salmonella activity of Fu-cCNPs was 2 fold higher than cCNPs and 6 fold higher than ciprofloxacin alone. Fluorescence microscopic images confirmed enhanced delivery of Fu-cCNPs than the cCNPs within the intracellular compartment of macrophages. Both cCNPs and Fu-cCNPs are found to be equally effective in dispersing Salmonella Paratyphi A gallstone biofilms. The in vivo antibacterial activities of Fu-cCNPs were superior to cCNPs which we have validated using Salmonella Paratyphi A infected Drosophila melanogaster fly model. Our overall results showed that (1) Fu-cCNPs are more effective in eradicating Salmonella infections than cCNPs; (2) both cCNPs and Fu-cCNPs were equally effective in dispersing Salmonella gallstone biofilms.}, } @article {pmid28922631, year = {2017}, author = {Wilson-Nieuwenhuis, JST and Dempsey-Hibbert, N and Liauw, CM and Whitehead, KA}, title = {Surface modification of platelet concentrate bags to reduce biofilm formation and transfusion sepsis.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {160}, number = {}, pages = {126-135}, doi = {10.1016/j.colsurfb.2017.09.019}, pmid = {28922631}, issn = {1873-4367}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Blood Platelets/*microbiology ; Hydrophobic and Hydrophilic Interactions ; Platelet Transfusion/adverse effects ; Product Packaging/*methods/standards ; Sepsis/etiology/*microbiology ; Serratia marcescens/*physiology ; Staphylococcus epidermidis/*physiology ; Surface Properties ; Time Factors ; }, abstract = {Bacterial contamination of blood products poses a major risk in transfusion medicine, including transfusions involving platelet products. Although testing systems are in place for routine screening of platelet units, the formation of bacterial biofilms in such units may decrease the likelihood that bacteria will be detected. This work determined the surface properties of p-PVC platelet concentrate bags and investigated how these characteristics influenced biofilm formation. Serratia marcescens and Staphylococcus epidermidis, two species commonly implicated in platelet contamination, were used to study biofilm growth. The platelet concentrate bags were physically flattened to determine if reducing the surface roughness altered biofilm formation. The results demonstrated that the flattening process of the platelet bags affected the chemistry of the surface and reduced the surface hydrophobicity. Flattening of the surfaces resulted in a reduction in biofilm formation for both species after 5 days, with S. marcescens demonstrating a greater reduction. However, there was no significant difference between the smooth and flat surfaces following 7 days' incubation for S. marcescens and no significant differences between any of the surfaces following 7 days' incubation for S. epidermidis. The results suggest that flattening the p-PVC surfaces may limit potential biofilm formation for the current duration of platelet storage time of 5 days. It is hoped that this work will enhance the understanding of how surface properties influence the development of microbial biofilms in platelet concentrate bags in order to devise a solution to discourage biofilm formation.}, } @article {pmid28920144, year = {2018}, author = {Malafaia, CB and Jardelino, ACS and Silva, AG and de Souza, EB and Macedo, AJ and Correia, MTDS and Silva, MV}, title = {Effects of Caatinga Plant Extracts in Planktonic Growth and Biofilm Formation in Ralstonia solanacearum.}, journal = {Microbial ecology}, volume = {75}, number = {3}, pages = {555-561}, pmid = {28920144}, issn = {1432-184X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Biological Control Agents/pharmacology ; Brazil ; Microbial Sensitivity Tests ; Plant Diseases/microbiology/prevention & control ; Plant Extracts/*pharmacology ; Plants, Medicinal ; Ralstonia solanacearum/*drug effects/physiology ; Tracheophyta/*chemistry ; }, abstract = {This study describes the first antibiofilm and antibacterial screening for plants from Caatinga against Ralstonia solanacearum, a causal agent of bacterial wilt that presents serious difficulties in control. There were prepared 22 aqueous extracts of plants collected in the Vale do Catimbau-PE, Brazil. The potential antibacterial activity was evaluated by absorbance in OD600 and the antibiofilm activity through the crystal violet method, both of them performed in microplate against isolates of R. solanacearum biofilm formers. The results of the screening showed that Jacaranda rugosa presented antimicrobial activity higher than 90%, while Harpochilus neesianus and Myroxylon peruiferum presented antibiofilm activity higher than 50% for all tested isolates. However, Croton heliotropiifolius showed both the activities, being thus very promising for application in the control of this phytopathogen. The search for viable alternatives to the development of new bioactive compounds safe for the environment, humans, and animals from an adverse and scarce environment such as the Caatinga and encouraged us to find plants that produce effective metabolites against phytopathogenic microorganisms. This in vitro screening is important to guide the development of new products in addition to guide research studies of bioactive compounds.}, } @article {pmid28919385, year = {2017}, author = {Singh, S and Adapa, LM and Hankins, N}, title = {Influences of ammonium and phosphate stimulation on metalworking fluid biofilm reactor development and performance.}, journal = {New biotechnology}, volume = {39}, number = {Pt B}, pages = {240-246}, doi = {10.1016/j.nbt.2017.09.002}, pmid = {28919385}, issn = {1876-4347}, mesh = {Ammonium Compounds/*pharmacology ; Biofilms/*drug effects ; *Bioreactors ; Carbon/isolation & purification ; Kinetics ; Metals/*chemistry ; Phosphates/*pharmacology ; }, abstract = {In this study, the effects of common wastewater stimulants, namely NH4Cl and KH2PO4, on the development and performance of metalworking fluid biofilm bioreactors are presented. It is shown that biofilms flourished only when one of these components was present in limiting quantities. Biofilm yields significantly declined when both of the components were withheld from the bioreactors or when both components were provided in excess. Stimulations to the reactors using NH4Cl significantly reduced the total carbon removal performance, while stimulations using KH2PO4 resulted in significant increases in performance. Chromatographic analyses showed that the NH4Cl stimulation enhanced the removal of saturated fatty amides and diethylene glycol butyl ether from the metalworking fluid, but inhibited the removal of diisoproponolamine. Furthermore, NH4Cl additions inhibited the oil/water separation carbon removal mechanism and resulted in the re-dispersion of recalcitrant organic material. The results from this study show that metalworking fluid practitioners should take care in choosing the nutrients used for stimulating bioreactor performance and microbe development. Incorrect stimulations with NH4Cl may result in negative treatment performances due to the inhibition of amine utilisation and enhancing emulsion stability.}, } @article {pmid28917762, year = {2018}, author = {Henkel, K and Altenburger, MJ and Auwärter, V and Neukamm, MA}, title = {Full validation of a method for the determination of drugs of abuse in non-mineralized dental biofilm using liquid chromatography-tandem mass spectrometry and application to postmortem samples.}, journal = {Talanta}, volume = {176}, number = {}, pages = {360-366}, doi = {10.1016/j.talanta.2017.08.047}, pmid = {28917762}, issn = {1873-3573}, mesh = {Amphetamines/analysis ; *Biofilms ; Chromatography, Liquid ; Cocaine/analogs & derivatives/analysis ; Dental Plaque/*chemistry/*microbiology ; Humans ; Illicit Drugs/*analysis ; Morphine Derivatives/analysis ; Reproducibility of Results ; Tandem Mass Spectrometry ; }, abstract = {Alternative matrices play a major role in postmortem forensic toxicology, especially if common matrices (like body fluids or hair) are not available. Incorporation of illicit and medicinal drugs into non-mineralized dental biofilm (plaque) seems likely but has not been investigated so far. Analysis of plaque could therefore extend the spectrum of potentially used matrices in postmortem toxicology. For this reason, a rapid, simple and sensitive method for the extraction, determination and quantification of ten drugs of abuse from plaque using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxyamphetamine (MDA), cocaine, benzoylecgonine, morphine, codeine and 6-acetylmorphine were extracted from 2mg of dried and powdered plaque via ultrasonication with acetonitrile. The extracts were analyzed on a triple-quadrupole linear ion trap mass spectrometer in scheduled multiple reaction monitoring mode (sMRM). The method was fully validated and proved accurate, precise, selective and specific with satisfactory linearity within the calibrated ranges. The lower limit of quantification was 10-15pgmg[-1] for all compounds except for MDA (100pgmg[-1]) and amphetamine (200pgmg[-1]). The method has been successfully applied to three authentic postmortem samples with known drug history. Amphetamine, MDMA, cocaine, benzoylecgonine, morphine and codeine could be detected in these cases in concentrations ranging from 18pgmg[-1] for cocaine to 1400pgmg[-1] for amphetamine.}, } @article {pmid28917089, year = {2017}, author = {Wolber, JM and Urbanek, BL and Meints, LM and Piligian, BF and Lopez-Casillas, IC and Zochowski, KM and Woodruff, PJ and Swarts, BM}, title = {The trehalose-specific transporter LpqY-SugABC is required for antimicrobial and anti-biofilm activity of trehalose analogues in Mycobacterium smegmatis.}, journal = {Carbohydrate research}, volume = {450}, number = {}, pages = {60-66}, pmid = {28917089}, issn = {1873-426X}, support = {R15 AI117670/AI/NIAID NIH HHS/United States ; }, mesh = {ATP-Binding Cassette Transporters/*metabolism ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Mycobacterium smegmatis/*drug effects/metabolism/*physiology ; Protein Transport/drug effects ; Trehalose/*metabolism ; }, abstract = {Mycobacteria, including the bacterial pathogen that causes human tuberculosis, possess distinctive pathways for synthesizing and utilizing the non-mammalian disaccharide trehalose. Trehalose metabolism is essential for mycobacterial viability and has been linked to in vitro biofilm formation, which may bear relevance to in vivo drug tolerance. Previous research has shown that some trehalose analogues bearing modifications at the 6-position inhibit growth of various mycobacterial species. In this work, 2-, 5-, and 6-position-modified trehalose analogues were synthesized using our previously reported one-step chemoenzymatic method and shown to inhibit growth and biofilm formation in the two-to three-digit micromolar range in Mycobacterium smegmatis. The trehalose-specific ABC transporter LpqY-SugABC was essential for antimicrobial and anti-biofilm activity, suggesting that inhibition by monosubstituted trehalose analogues requires cellular uptake and does not proceed via direct action on extracellular targets such as antigen 85 acyltransferases or trehalose dimycolate hydrolase. Although the potency of the described compounds in in vitro growth and biofilm assays is moderate, this study reports the first trehalose-based mycobacterial biofilm inhibitors and reinforces the concept of exploiting unique sugar uptake pathways to deliver inhibitors and other chemical cargo to mycobacteria.}, } @article {pmid28916465, year = {2018}, author = {Fukushima, A and Mayanagi, G and Sasaki, K and Takahashi, N}, title = {Corrosive effects of fluoride on titanium under artificial biofilm.}, journal = {Journal of prosthodontic research}, volume = {62}, number = {1}, pages = {104-109}, doi = {10.1016/j.jpor.2017.08.004}, pmid = {28916465}, issn = {2212-4632}, mesh = {*Biofilms ; Corrosion ; Dental Materials/*chemistry ; Electrochemistry ; Hydrogen-Ion Concentration ; Sodium Fluoride/*chemistry/pharmacology ; Solutions ; Streptococcus mutans/drug effects/*physiology ; Temperature ; Time Factors ; Titanium/*chemistry ; }, abstract = {PURPOSE: This study aimed to investigate the effect of sodium fluoride (NaF) on titanium corrosion using a biofilm model, taking environmental pH into account.

METHODS: Streptococcus mutans cells were used as the artificial biofilm, and pH at the bacteria-titanium interface was monitored after the addition of 1% glucose with NaF (0, 225 or 900ppmF) at 37°C for 90min. In an immersion test, the titanium samples were immersed in the NaF solution (0, 225 or 900ppm F; pH 4.2 or 6.5) for 30 or 90min. Before and after pH monitoring or immersion test, the electrochemical properties of the titanium surface were measured using a potentiostat. The amount of titanium eluted into the biofilm or the immersion solution was measured using inductively coupled plasma mass spectrometry. The color difference (ΔE*ab) and gloss of the titanium surface were determined using a spectrophotometer.

RESULTS: After incubation with biofilm, pH was maintained at around 6.5 in the presence of NaF. There was no significant change in titanium surface and elution, regardless of the concentration of NaF. After immersion in 900ppm NaF solution at pH 4.2, corrosive electrochemical change was induced on the surface, titanium elution and ΔE*ab were increased, and gloss was decreased.

CONCLUSIONS: NaF induces titanium corrosion in acidic environment in vitro, while NaF does not induce titanium corrosion under the biofilm because fluoride inhibits bacterial acid production. Neutral pH fluoridated agents may still be used to protect the remaining teeth, even when titanium-based prostheses are worn.}, } @article {pmid28916319, year = {2017}, author = {Saleem, S and Ahmed, B and Khan, MS and Al-Shaeri, M and Musarrat, J}, title = {Inhibition of growth and biofilm formation of clinical bacterial isolates by NiO nanoparticles synthesized from Eucalyptus globulus plants.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {375-387}, doi = {10.1016/j.micpath.2017.09.019}, pmid = {28916319}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*biosynthesis/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects/growth & development/physiology ; Eucalyptus/*chemistry/metabolism ; Humans ; Metal Nanoparticles/chemistry ; Methicillin-Resistant Staphylococcus aureus/drug effects/growth & development/physiology ; Microbial Sensitivity Tests ; Nickel/*metabolism/*pharmacology ; Plant Extracts/*chemistry/metabolism ; Pseudomonas aeruginosa/drug effects/growth & development/physiology ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Nanotechnology based therapeutics has emerged as a promising approach for augmenting the activity of existing antimicrobials due to the unique physical and chemical properties of nanoparticles (NPs). Nickel oxide nanoparticles (NiO-NPs) have been suggested as prospective antibacterial and antitumor agent. In this study, NiO-NPs have been synthesized by a green approach using Eucalyptus globulus leaf extract and assessed for their bactericidal activity. The morphology and purity of synthesized NiO-NPs determined through various spectroscopic techniques like UV-Visible, FT-IR, XRD, EDX and electron microscopy differed considerably. The synthesized NiO-NPs were pleomorphic varying in size between 10 and 20 nm. The XRD analysis revealed the average size of NiO-NPs as 19 nm. The UV-Vis spectroscopic data showed a strong SPR of NiO-NPs with a characteristic spectral peak at 396 nm. The FTIR data revealed various functional moieties like C=C, C-N, C-H and O-H which elucidate the role of leaf biomolecules in capping and dispersal of NiO-NPs. The bioactivity assay revealed the antibacterial and anti-biofilm activity of NiO-NPs against ESβL (+) E. coli, P. aeruginosa, methicillin sensitive and resistant S. aureus. Growth inhibition assay demonstrated time and NiO-NPs concentration dependent decrease in the viability of treated cells. NiO-NPs induced biofilm inhibition was revealed by a sharp increase in characteristic red fluorescence of PI, while SEM images of NiO-NPs treated cells were irregular shrink and distorted with obvious depressions/indentations. The results suggested significant antibacterial and antibiofilm activity of NiO-NPs which may play an important role in the management of infectious diseases affecting human health.}, } @article {pmid28915875, year = {2017}, author = {Vasconcelos, SECB and Melo, HM and Cavalcante, TTA and Júnior, FEAC and de Carvalho, MG and Menezes, FGR and de Sousa, OV and Costa, RA}, title = {Plectranthus amboinicus essential oil and carvacrol bioactive against planktonic and biofilm of oxacillin- and vancomycin-resistant Staphylococcus aureus.}, journal = {BMC complementary and alternative medicine}, volume = {17}, number = {1}, pages = {462}, pmid = {28915875}, issn = {1472-6882}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cymenes ; *Drug Resistance, Bacterial ; Humans ; Monoterpenes/*pharmacology ; Oils, Volatile/*pharmacology ; Oxacillin/pharmacology ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Plectranthus/*chemistry ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/growth & development/physiology ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: The emergence of multidrug-resistant bacteria is a worldwide concern and in order to find an alternative to this problem, the occurrence of antimicrobial compounds in Plectranthus amboinicus essential oil was investigated. Thus, this study aims to determine susceptibility of Staphylococcus aureus isolated from food to antibiotics, P. amboinicus essential oil (PAEO) and carvacrol.

METHODS: Leaves and stem of P. amboinicus were used for extraction of essential oil (PAEO) by hydrodistillation technique and EO chemical analysis was performed by gas chromatography coupled to a mass spectrometer. S. aureus strains (n = 35) isolated from food and S. aureus ATCC 6538 were used to evaluate the antimicrobial and antibiofilm activity of PAEO and carvacrol. All strains (n = 35) were submitted to antimicrobial susceptibility profile by disk diffusion method. Determination of MIC and MBC was performed by microdilution technique and antibiofilm activity was determined by microtiter-plate technique with crystal violet assay and counting viable cells in Colony Forming Units (CFU).

RESULTS: Carvacrol (88.17%) was the major component in the PAEO. Antibiotic resistance was detected in 28 S. aureus strains (80%) and 12 strains (34.3%) were oxacillin and vancomycin-resistant (OVRSA). From the 28 resistant strains, 7 (25%) showed resistance plasmid of 12,000 bp. All strains (n = 35) were sensitive to PAEO and carvacrol, with inhibition zones ranging from 16 to 38 mm and 23 to 42 mm, respectively. The lowest MIC (0.25 mg mL[-1]) and MBC (0.5 mg mL[-1]) values were observed when carvacrol was used against OVRSA. When a 0.5 mg mL[-1] concentration of PAEO and carvacrol was used, no viable cells were found on S. aureus biofilm.

CONCLUSION: The antibacterial effect of carvacrol and PAEO proves to be a possible alternative against planktonic forms and staphylococcal biofilm.}, } @article {pmid28915490, year = {2017}, author = {Pani, T and Das, A and Osborne, JW}, title = {Bioremoval of zinc and manganese by bacterial biofilm: A bioreactor-based approach.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {175}, number = {}, pages = {211-218}, doi = {10.1016/j.jphotobiol.2017.08.039}, pmid = {28915490}, issn = {1873-2682}, mesh = {Adsorption ; Bacteria/classification/*genetics/growth & development ; Biofilms/*growth & development ; Bioreactors ; Kinetics ; Manganese/chemistry/*metabolism ; Microscopy, Electron, Scanning ; RNA, Ribosomal, 16S/classification/genetics/metabolism ; Substrate Specificity ; Waste Disposal, Fluid ; Water Pollutants, Chemical/chemistry/*metabolism ; Zinc/chemistry/*metabolism ; }, abstract = {Industrialization has led to the disposal of a massive amount of heavy metals every year, showing perilous effects on humans, marine life and agricultural products. There are numerous chemical and biological approaches available but their implementation is limited due to high cost and low efficiency. Therefore, the present study was focused on the biofilm- based bioremoval of heavy metals (zinc and manganese) using indigenous bacteria isolated from the tannery sludge obtained from Ranipet, Tamil Nadu. The effective isolate was capable of tolerating up to 2000mg/L of zinc and manganese and was further used for development of biofilm on the peels of Cucumis sativus. The isolate was found to be a close neighbour of Pseudomonas beteli by 16S rRNA gene sequencing. The uptake efficiency of the biofilm formed on the substrate was estimated to be 69.9% for zinc and 78.4% for manganese by atomic absorption spectroscopy. The scanning electron microscopy showed the biofilm formation on the substrate and also revealed the presence of heavy metal ions adsorbed on the biofilm. The adsorption kinetics of the substrate followed a heterogeneous mode of adsorption of the heavy metals as it showed a higher R[2] value for the Freundlich isotherm kinetics as compared to that of Langmuir. Thus, the peels of Cucumis sativus was assessed to be effective for the bioremoval of zinc and manganese.}, } @article {pmid28914748, year = {2017}, author = {Piperaki, ET and Syrogiannopoulos, GA and Tzouvelekis, LS and Daikos, GL}, title = {Klebsiella pneumoniae: Virulence, Biofilm and Antimicrobial Resistance.}, journal = {The Pediatric infectious disease journal}, volume = {36}, number = {10}, pages = {1002-1005}, doi = {10.1097/INF.0000000000001675}, pmid = {28914748}, issn = {1532-0987}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms/drug effects ; Disease Management ; Drug Resistance, Bacterial ; Host-Pathogen Interactions ; Humans ; Klebsiella Infections/drug therapy/immunology/*microbiology ; Klebsiella pneumoniae/drug effects/*physiology ; Virulence ; Virulence Factors ; }, } @article {pmid28913903, year = {2017}, author = {Krzyściak, P and Chmielarczyk, A and Pobiega, M and Romaniszyn, D and Wójkowska-Mach, J}, title = {Acinetobacter baumannii isolated from hospital-acquired infection: biofilm production and drug susceptibility.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {11}, pages = {1017-1026}, doi = {10.1111/apm.12739}, pmid = {28913903}, issn = {1600-0463}, mesh = {Acinetobacter Infections/drug therapy/*microbiology ; Acinetobacter baumannii/*drug effects/growth & development/isolation & purification ; Aged ; Aminoglycosides/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cephalosporins/pharmacology ; Cross Infection/drug therapy/*microbiology ; Culture Media/chemistry ; Drug Resistance, Multiple, Bacterial/physiology ; Female ; Fluoroquinolones/pharmacology ; Humans ; Intensive Care Units ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Plankton/*drug effects/growth & development/isolation & purification ; Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology ; }, abstract = {Acinetobacter baumannii cause opportunistic nosocomial infections and is often multidrug resistant. It has ability to form biofilm. The possession of drug resistance mechanism and ability of biofilm formation seems to be the different way to enhancement of viability in stressful environment. In this study, we evaluate relation between these two factors. The biofilm formation was investigated in M63 medium with casein in microtiter plates, and the drug susceptibility was performed by disk diffusion methods. We found that 80-98% strains formed a biofilm. Strains showing sensitivity to amikacin and tobramycin from ICU produced more biofilm than strains showing resistance to these antibiotics. Ceftazidime-sensitive strains formed a smaller biofilm than resistant. The logistic regression shows association between drug resistance and strains originating from ICU. In case of ceftazidime, strong biofilm formation and descending from ICU reduced the likelihood of drug sensitivity. For other drugs such as aminoglycosides, fluoroquinolones, trimethoprim/sulfamethoxazole, and tetracycline, we found opposite relation (but it was not statistically significance). However, generally it seems that strong biofilm producers from ICUs are often more susceptible to antibiotics. This situation can be explained by the fact that bacteria protected in biofilm do not need mechanisms responsible for resistance of planktonic cells.}, } @article {pmid28913868, year = {2017}, author = {Cimdins, A and Simm, R and Li, F and Lüthje, P and Thorell, K and Sjöling, Å and Brauner, A and Römling, U}, title = {Alterations of c-di-GMP turnover proteins modulate semi-constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli.}, journal = {MicrobiologyOpen}, volume = {6}, number = {5}, pages = {}, pmid = {28913868}, issn = {2045-8827}, mesh = {Amino Acid Substitution ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Enzyme Activation ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Profiling ; Genome, Bacterial ; Humans ; Mutation ; Phenotype ; Phylogeny ; Uropathogenic Escherichia coli/classification/*physiology ; }, abstract = {Agar plate-based biofilm of enterobacteria like Escherichia coli is characterized by expression of the extracellular matrix components amyloid curli and cellulose exopolysaccharide, which can be visually enhanced upon addition of the dye Congo Red, resulting in a red, dry, and rough (rdar) colony morphology. Expression of the rdar morphotype depends on the transcriptional regulator CsgD and occurs predominantly at ambient temperature in model strains. In contrast, commensal and pathogenic isolates frequently express the csgD-dependent rdar morphotype semi-constitutively, also at human host body temperature. To unravel the molecular basis of temperature-independent rdar morphotype expression, biofilm components and c-di-GMP turnover proteins of seven commensal and uropathogenic E. coli isolates were analyzed. A diversity within the c-di-GMP signaling network was uncovered which suggests alteration of activity of the trigger phosphodiesterase YciR to contribute to (up)regulation of csgD expression and consequently semi-constitutive rdar morphotype development.}, } @article {pmid28913680, year = {2017}, author = {Pfendler, S and Einhorn, O and Karimi, B and Bousta, F and Cailhol, D and Alaoui-Sosse, L and Alaoui-Sosse, B and Aleya, L}, title = {UV-C as an efficient means to combat biofilm formation in show caves: evidence from the La Glacière Cave (France) and laboratory experiments.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {31}, pages = {24611-24623}, pmid = {28913680}, issn = {1614-7499}, mesh = {Bacteria/radiation effects ; Biofilms/*radiation effects ; *Caves/microbiology ; France ; Fungi/radiation effects ; Paintings ; Photosynthesis/radiation effects ; Sterilization/methods ; *Ultraviolet Rays ; }, abstract = {Ultra-violet C (UV-C) treatment is commonly used in sterilization processes in industry, laboratories, and hospitals, showing its efficacy against microorganisms such as bacteria, algae, or fungi. In this study, we have eradicated for the first time all proliferating biofilms present in a show cave (the La Glacière Cave, Chaux-lès-Passavant, France). Colorimetric measurements of irradiated biofilms were then monitored for 21 months. To understand the importance of exposition of algae to light just after UV radiation, similar tests were carried out in laboratory conditions. Since UV-C can be deleterious for biofilm support, especially parietal painting, we investigated their effects on prehistoric pigment. Results showed complete eradication of cave biofilms with no algae proliferation observed after 21 months. Moreover, quantum yield results showed a decrease directly after UV-C treatment, indicating inhibition of algae photosynthesis. Furthermore, no changes in pigment color nor in chemical and crystalline properties has been demonstrated. The present findings demonstrate that the UV-C method can be considered environmentally friendly and the best alternative to chemicals. This inexpensive and easily implemented method is advantageous for cave owners and managers.}, } @article {pmid28910644, year = {2017}, author = {Xu, Y and Wang, C and Hou, J and Wang, P and Miao, L and You, G and Lv, B and Yang, Y and Zhang, F}, title = {Long term effects of cerium dioxide nanoparticles on the nitrogen removal, micro-environment and community dynamics of a sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {245}, number = {Pt A}, pages = {573-580}, doi = {10.1016/j.biortech.2017.08.201}, pmid = {28910644}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Cerium ; *Denitrification ; *Nanoparticles ; Nitrogen ; }, abstract = {The influences of cerium dioxide nanoparticles (CeO2 NPs) on nitrogen removal in biofilm were investigated. Prolonged exposure (75d) to 0.1mg/L CeO2 NPs caused no inhibitory effects on nitrogen removal, while continuous addition of 10mg/L CeO2 NPs decreased the treatment efficiency to 53%. With the progressive concentration of CeO2 NPs addition, the removal efficiency could nearly stabilize at 67% even with the continues spike of 10mg/L. The micro-profiles of dissolved oxygen, pH, and oxidation reduction potential suggested the developed protection mechanisms of microbes to progressive CeO2 NPs exposure led to the less influence of microenvironment, denitrification bacteria and enzyme activity than those with continuous ones. Furthermore, high throughput sequencing illustrated the drastic shifted communities with gradual CeO2 NPs spiking was responsible for the adaption and protective mechanisms. The present study demonstrated the acclimated microbial community was able to survive CeO2 NPs addition more readily than those non-acclimated.}, } @article {pmid28910576, year = {2017}, author = {Rom, JS and Atwood, DN and Beenken, KE and Meeker, DG and Loughran, AJ and Spencer, HJ and Lantz, TL and Smeltzer, MS}, title = {Impact of Staphylococcus aureus regulatory mutations that modulate biofilm formation in the USA300 strain LAC on virulence in a murine bacteremia model.}, journal = {Virulence}, volume = {8}, number = {8}, pages = {1776-1790}, pmid = {28910576}, issn = {2150-5608}, support = {R01 AI119380/AI/NIAID NIH HHS/United States ; P30 GM103450/GM/NIGMS NIH HHS/United States ; UL1 TR000039/TR/NCATS NIH HHS/United States ; }, mesh = {Animals ; Bacteremia/*microbiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Disease Models, Animal ; Female ; Gene Expression Regulation, Bacterial ; Humans ; Mice ; Mutation ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*genetics/pathogenicity/physiology ; Virulence ; }, abstract = {Staphylococcus aureus causes acute and chronic forms of infection, the latter often associated with formation of a biofilm. It has previously been demonstrated that mutation of atl, codY, rot, sarA, and sigB limits biofilm formation in the USA300 strain LAC while mutation of agr, fur, and mgrA has the opposite effect. Here we used a murine sepsis model to assess the impact of these same loci in acute infection. Mutation of agr, atl, and fur had no impact on virulence, while mutation of mgrA and rot increased virulence. In contrast, mutation of codY, sarA, and sigB significantly attenuated virulence. Mutation of sigB resulted in reduced accumulation of AgrA and SarA, while mutation of sarA resulted in reduced accumulation of AgrA, but this cannot account for the reduced virulence of sarA or sigB mutants because the isogenic agr mutant was not attenuated. Indeed, as assessed by accumulation of alpha toxin and protein A, all of the mutants we examined exhibited unique phenotypes by comparison to an agr mutant and to each other. Attenuation of the sarA, sigB and codY mutants was correlated with increased production of extracellular proteases and global changes in extracellular protein profiles. These results suggest that the inability to repress the production of extracellular proteases plays a key role in attenuating the virulence of S. aureus in acute as well as chronic, biofilm-associated infections, thus opening up the possibility that strategies aimed at the de-repression of protease production could be used to broad therapeutic advantage. They also suggest that the impact of codY, sarA, and sigB on protease production occurs via an agr-independent mechanism.}, } @article {pmid28905757, year = {2017}, author = {Schaeffer, EM}, title = {Re: Development and Characterization of a Stable Adhesive Bond between a Poly(dimethylsiloxane) Catheter Material and a Bacterial Biofilm Resistant Acrylate Polymer Coating.}, journal = {The Journal of urology}, volume = {198}, number = {4}, pages = {726}, doi = {10.1016/j.juro.2017.07.007}, pmid = {28905757}, issn = {1527-3792}, mesh = {Acrylates ; *Adhesives ; Biofilms ; Dimethylpolysiloxanes ; *Polymers ; }, } @article {pmid28905285, year = {2018}, author = {Sharma, V and Harjai, K and Shukla, G}, title = {Effect of bacteriocin and exopolysaccharides isolated from probiotic on P. aeruginosa PAO1 biofilm.}, journal = {Folia microbiologica}, volume = {63}, number = {2}, pages = {181-190}, pmid = {28905285}, issn = {1874-9356}, support = {F.7-261/2009//University Grants Commission/ ; }, mesh = {Anti-Bacterial Agents/metabolism/*pharmacology ; Bacteriocins/metabolism/*pharmacology ; Biofilms/*drug effects ; Feces/microbiology ; Female ; Humans ; Infant ; Lactobacillales/*chemistry/genetics/isolation & purification/*metabolism ; Male ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/*metabolism ; Probiotics/metabolism/*pharmacology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; }, abstract = {Microorganisms develop biofilms on indwelling medical devices and are associated with biofilm-related infections, resulting in substantial morbidity and mortality. Therefore, to prevent and control biofilm-associated infections, the present study was designed to assess the anti-biofilm potential of postbiotics derived from probiotic organisms against most prevalent biofilm-forming Pseudomonas aeruginosa PAO1. Eighty lactic acid bacteria isolated from eight neonatal fecal samples possessed antibacterial activity against P. aeruginosa PAO1. Among these, only four lactic acid bacteria produced both bacteriocin and exopolysaccharides but only one isolate was found to maximally attenuate the P. aeruginosa PAO1 biofilm. More specifically, the phenotypic and probiotic characterization showed that the isolated lactic acid bacteria were gram positive, non-motile, and catalase and oxidase negative; tolerated acidic and alkaline pH; has bile salt concentration; showed 53% hydrophobicity; and was found to be non-hemolytic. Phylogenetically, the organism was found to be probiotic Lactobacillus fermentum with accession no. KT998657. Interestingly, pre-coating of a microtiter plate either with bacteriocin or with exopolysaccharides as well as their combination significantly (p < 0.05) reduced the number of viable cells forming biofilms to 41.7% compared with simultaneous coating of postbiotics that had 72.4% biofilm-forming viable cells as observed by flow cytometry and confocal laser scanning microscopy. Therefore, it can be anticipated that postbiotics as the natural biointerventions can be employed as the prophylactic agents for medical devices used to treat gastrointestinal and urinary tract infections.}, } @article {pmid28904996, year = {2017}, author = {Kumar, S and Spiro, S}, title = {Environmental and Genetic Determinants of Biofilm Formation in Paracoccus denitrificans.}, journal = {mSphere}, volume = {2}, number = {5}, pages = {}, pmid = {28904996}, issn = {2379-5042}, abstract = {The genome of the denitrifying bacterium Paracoccus denitrificans predicts the expression of a small heme-containing nitric oxide (NO) binding protein, H-NOX. The genome organization and prior work in other bacteria suggest that H-NOX interacts with a diguanylate cyclase that cyclizes GTP to make cyclic di-GMP (cdGMP). Since cdGMP frequently regulates attached growth as a biofilm, we first established conditions for biofilm development by P. denitrificans. We found that adhesion to a polystyrene surface is strongly stimulated by the addition of 10 mM Ca[2+] to rich media. The genome encodes at least 11 repeats-in-toxin family proteins that are predicted to be secreted by the type I secretion system (TISS). We deleted the genes encoding the TISS and found that the mutant is almost completely deficient for attached growth. Adjacent to the TISS genes there is a potential open reading frame encoding a 2,211-residue protein with 891 Asp-Ala repeats. This protein is also predicted to bind calcium and to be a TISS substrate, and a mutant specifically lacking this protein is deficient in biofilm formation. By analysis of mutants and promoter reporter fusions, we show that biofilm formation is stimulated by NO generated endogenously by the respiratory reduction of nitrite. A mutant lacking both predicted diguanylate cyclases encoded in the genome overproduces biofilm, implying that cdGMP is a negative regulator of attached growth. Our data are consistent with a model in which there are H-NOX-dependent and -independent pathways by which NO stimulates biofilm formation. IMPORTANCE The bacterium Paracoccus denitrificans is a model for the process of denitrification, by which nitrate is reduced to dinitrogen during anaerobic growth. Denitrification is important for soil fertility and greenhouse gas emission and in waste and water treatment processes. The ability of bacteria to grow as a biofilm attached to a solid surface is important in many different contexts. In this paper, we report that attached growth of P. denitrificans is stimulated by nitric oxide, an intermediate in the denitrification pathway. We also show that calcium ions stimulate attached growth, and we identify a large calcium binding protein that is required for growth on a polystyrene surface. We identify components of a signaling pathway through which nitric oxide may regulate biofilm formation. Our results point to an intimate link between metabolic processes and the ability of P. denitrificans to grow attached to a surface.}, } @article {pmid28902153, year = {2017}, author = {Jakobsen, TH and Tolker-Nielsen, T and Givskov, M}, title = {Bacterial Biofilm Control by Perturbation of Bacterial Signaling Processes.}, journal = {International journal of molecular sciences}, volume = {18}, number = {9}, pages = {}, pmid = {28902153}, issn = {1422-0067}, mesh = {Bacteria/drug effects/*metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Humans ; Quorum Sensing/*physiology ; Signal Transduction/*physiology ; }, abstract = {The development of effective strategies to combat biofilm infections by means of either mechanical or chemical approaches could dramatically change today's treatment procedures for the benefit of thousands of patients. Remarkably, considering the increased focus on biofilms in general, there has still not been invented and/or developed any simple, efficient and reliable methods with which to "chemically" eradicate biofilm infections. This underlines the resilience of infective agents present as biofilms and it further emphasizes the insufficiency of today's approaches used to combat chronic infections. A potential method for biofilm dismantling is chemical interception of regulatory processes that are specifically involved in the biofilm mode of life. In particular, bacterial cell to cell signaling called "Quorum Sensing" together with intracellular signaling by bis-(3'-5')-cyclic-dimeric guanosine monophosphate (cyclic-di-GMP) have gained a lot of attention over the last two decades. More recently, regulatory processes governed by two component regulatory systems and small non-coding RNAs have been increasingly investigated. Here, we review novel findings and potentials of using small molecules to target and modulate these regulatory processes in the bacterium Pseudomonas aeruginosa to decrease its pathogenic potential.}, } @article {pmid28900144, year = {2017}, author = {Ali-Ahmad, A and Fadel, F and Sebban-Kreuzer, C and Ba, M and Pélissier, GD and Bornet, O and Guerlesquin, F and Bourne, Y and Bordi, C and Vincent, F}, title = {Structural and functional insights into the periplasmic detector domain of the GacS histidine kinase controlling biofilm formation in Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {11262}, pmid = {28900144}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Catalytic Domain ; Histidine Kinase/*chemistry/genetics/*metabolism ; Magnetic Resonance Spectroscopy ; Mutant Proteins/chemistry/genetics/metabolism ; Periplasmic Proteins/*chemistry/genetics/*metabolism ; Point Mutation ; Protein Conformation ; Pseudomonas aeruginosa/*enzymology/genetics/growth & development ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogenic bacterium responsible for both acute and chronic infections and has developed resistance mechanisms due to its ability to promote biofilm formation and evade host adaptive immune responses. Here, we investigate the functional role of the periplasmic detector domain (GacSPD) from the membrane-bound GacS histidine kinase, which is one of the key players for biofilm formation and coordination of bacterial lifestyles. A gacS mutant devoid of the periplasmic detector domain is severely defective in biofilm formation. Functional assays indicate that this effect is accompanied by concomitant changes in the expression of the two RsmY/Z small RNAs that control activation of GacA-regulated genes. The solution NMR structure of GacSPD reveals a distinct PDC/PAS α/β fold characterized by a three-stranded β-sheet flanked by α-helices and an atypical major loop. Point mutations in a putative ligand binding pocket lined by positively-charged residues originating primarily from the major loop impaired biofilm formation. These results demonstrate the functional role of GacSPD, evidence critical residues involved in GacS/GacA signal transduction system that regulates biofilm formation, and document the evolutionary diversity of the PDC/PAS domain fold in bacteria.}, } @article {pmid28900103, year = {2017}, author = {Martinez-Gil, M and Goh, KGK and Rackaityte, E and Sakamoto, C and Audrain, B and Moriel, DG and Totsika, M and Ghigo, JM and Schembri, MA and Beloin, C}, title = {YeeJ is an inverse autotransporter from Escherichia coli that binds to peptidoglycan and promotes biofilm formation.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {11326}, pmid = {28900103}, issn = {2045-2322}, mesh = {*Biofilms/growth & development ; Cell Membrane/metabolism ; Cloning, Molecular ; Computational Biology/methods ; Conserved Sequence ; Escherichia coli/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Evolution, Molecular ; Gene Expression ; Gene Expression Regulation, Bacterial ; Gene Order ; Genome, Bacterial ; Peptidoglycan/*metabolism ; Phenotype ; Polyribonucleotide Nucleotidyltransferase/metabolism ; Protein Binding ; Protein Interaction Domains and Motifs ; Type V Secretion Systems/genetics/*metabolism ; }, abstract = {Escherichia coli is a commensal or pathogenic bacterium that can survive in diverse environments. Adhesion to surfaces is essential for E. coli colonization, and thus it is important to understand the molecular mechanisms that promote this process in different niches. Autotransporter proteins are a class of cell-surface factor used by E. coli for adherence. Here we characterized the regulation and function of YeeJ, a poorly studied but widespread representative from an emerging class of autotransporter proteins, the inverse autotransporters (IAT). We showed that the yeeJ gene is present in ~40% of 96 completely sequenced E. coli genomes and that YeeJ exists as two length variants, albeit with no detectable functional differences. We demonstrated that YeeJ promotes biofilm formation in different settings through exposition at the cell-surface. We also showed that YeeJ contains a LysM domain that interacts with peptidoglycan and thus assists its localization into the outer membrane. Additionally, we identified the Polynucleotide Phosphorylase PNPase as a repressor of yeeJ transcription. Overall, our work provides new insight into YeeJ as a member of the recently defined IAT class, and contributes to our understanding of how commensal and pathogenic E. coli colonise their environments.}, } @article {pmid28899678, year = {2017}, author = {Zhang, X and Song, Z and Guo, W and Lu, Y and Qi, L and Wen, H and Ngo, HH}, title = {Behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {245}, number = {Pt A}, pages = {1282-1285}, doi = {10.1016/j.biortech.2017.08.106}, pmid = {28899678}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Denitrification ; Nitrification ; Nitrogen ; }, abstract = {This study aims to investigate the behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor by evaluating nitrification and denitrification rates of sponge biocarriers from three aerobic moving bed biofilm reactors (MBBRs) with filling ratios of 10% (R-10), 20% (R-20) and 30% (R-30). Results showed that the highest removal efficiencies of total nitrogen in three reactors were 84.5% (R-10), 93.6% (R-20) and 95.3% (R-30). Correspondingly, simultaneous nitrification and denitrification rate (SND) was 90.9%, 97.6% and 100%, respectively. Although R-20 had the highest attached-growth biomass (AGB) per gram of sponge compared to the other two reactors, R-30 showed the maximum ammonium oxidation rate (AOR) (2.1826±0.0717mgNH4[+]-N/gAGB/h) and denitrification rate (DNR) (5.0852±0.0891mgNO3[-]-N/gAGB/h), followed by R-20 and R-10. These results indicated AOR, DNR and AGB were affected by the filling ratio under the same operation mode.}, } @article {pmid28899676, year = {2017}, author = {Kim, B and Choi, S and Jang, JK and Chang, IS}, title = {Self-recoverable voltage reversal in stacked microbial fuel cells due to biofilm capacitance.}, journal = {Bioresource technology}, volume = {245}, number = {Pt A}, pages = {1286-1289}, doi = {10.1016/j.biortech.2017.08.163}, pmid = {28899676}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Electric Capacitance ; Electrodes ; Reproducibility of Results ; }, abstract = {In order to assess the effects of biofilm capacitance on self-recovering voltage reversals, the restored current is determined and compared with the measured biofilm capacitance by analyzing the results of electrochemical impedance spectroscopy. This comparison demonstrates that self-recovering voltage reversals are caused by temporary damage to, and the recovery of, biofilm capacitance which arises due to the ability of redox enzymes in the electron transfer system to temporarily store electrons. Thus, the development of procedures for voltage reversal control and for the maintenance of serially connected microbial fuel cells (MFCs) should take into account such temporary voltage reversal phenomenon. This discovery and characterization of self-recovering voltage reversals is expected to be practically useful to enhance the reliability of MFCs to be scaled up and implemented in practical systems.}, } @article {pmid28898513, year = {2018}, author = {Tsutsumi, K and Maruyama, M and Uchiyama, A and Shibasaki, K}, title = {Characterisation of a sucrose-independent in vitro biofilm model of supragingival plaque.}, journal = {Oral diseases}, volume = {24}, number = {3}, pages = {465-475}, doi = {10.1111/odi.12779}, pmid = {28898513}, issn = {1601-0825}, mesh = {Actinomyces ; *Bacterial Physiological Phenomena ; Biofilms/*drug effects ; Dental Caries/microbiology ; Dental Plaque/*etiology ; Fusobacterium nucleatum ; Hydrogen-Ion Concentration ; In Situ Hybridization, Fluorescence ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Models, Biological ; Streptococcus gordonii ; Streptococcus mutans ; Sucrose/pharmacology ; Sweetening Agents/pharmacology ; Veillonella ; }, abstract = {OBJECTIVES: Sugar consumption has been decreasing in Japan, suggesting higher rates of sucrose-independent supragingival plaque formation. For developing an in vitro biofilm model of sucrose-independent supragingival plaque, this study aimed to investigate the compositions and functions on contributing to cariogenicity in comparison with sucrose-dependent biofilm.

MATERIALS AND METHODS: An in vitro multispecies biofilm containing Actinomyces naeslundii, Streptococcus gordonii, S. mutans, Veillonella parvula and Fusobacterium nucleatum was formed on 24-well plates in the absence or presence of 1% sucrose. Compositions were assessed by plate culture, scanning electron microscopy and confocal laser scanning microscopy after fluorescent in situ hybridisation or labelling of extracellular polymeric substances (EPS). Functions were assessed by acidogenicity, adherence strength and sensitivities to anticaries agents.

RESULTS: Although both biofilms exhibited a Streptococcus predominant bacterial composition, there were differences in bacterial and EPS compositions; in particular, little glucan EPS was observed in sucrose-independent biofilm. Compared with sucrose-dependent biofilm, acidogenicity, adherence strength and antimicrobial resistance of sucrose-independent biofilm were only slightly lower. However, dextranase degradation was substantially lower in sucrose-independent biofilm.

CONCLUSION: Our findings suggest that sucrose-independent biofilm may have cariogenicity as with sucrose-dependent biofilm. These in vitro models can help further elucidate plaque-induced caries aetiology and develop new anticaries agents.}, } @article {pmid28893789, year = {2017}, author = {Algburi, A and Zhang, Y and Weeks, R and Comito, N and Zehm, S and Pinto, J and Uhrich, KE and Chikindas, ML}, title = {Gemini Cationic Amphiphiles Control Biofilm Formation by Bacterial Vaginosis Pathogens.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {12}, pages = {}, pmid = {28893789}, issn = {1098-6596}, support = {R21 AI126053/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*growth & development ; Drug Synergism ; Female ; Gardnerella vaginalis/*drug effects ; Humans ; Lactobacillus plantarum/*drug effects ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; Surface-Active Agents/*pharmacology ; Vagina/microbiology ; Vaginosis, Bacterial/*drug therapy/microbiology ; }, abstract = {Antibiotic resistance and recurrence of bacterial vaginosis (BV), a polymicrobial infection, justify the need for novel antimicrobials to counteract microbial resistance to conventional antibiotics. Previously, two series of cationic amphiphiles (CAms) which self-assemble into supramolecular nanostructures with membrane-lytic properties were designed with hydrophilic head groups and nonpolar domains. The combination of CAms and commonly prescribed antibiotics is suggested as a promising strategy for targeting microorganisms that are resistant to conventional antibiotics. Activities of the CAms against Gardnerella vaginalis ATCC 14018, a representative BV pathogen, ranged from 1.1 to 24.4 μM. Interestingly, the tested healthy Lactobacillus species, especially Lactobacillus plantarum ATCC 39268, were significantly more tolerant of CAms than the selected pathogens. In addition, CAms prevented biofilm formation at concentrations which did not influence the normal growth ability of G. vaginalis ATCC 14018. Furthermore, the biofilm minimum bactericidal concentration (MBC-Bs) of CAms against G. vaginalis ATCC 14018 ranged from 58.8 to 425.6 μM, while much higher concentrations (≥850 μM) were required to produce ≥3-log reductions in the number of biofilm-associated lactobacilli. The conventional antibiotic metronidazole synergized strongly with all tested CAms against planktonic cells and biofilms of G. vaginalis ATCC 14018. The synergism between CAms and the tested conventional antibiotic may be considered a new, effective, and beneficial method of controlling biofilm-associated bacterial vaginosis.}, } @article {pmid28893370, year = {2017}, author = {Kannappan, A and Sivaranjani, M and Srinivasan, R and Rathna, J and Pandian, SK and Ravi, AV}, title = {Inhibitory efficacy of geraniol on biofilm formation and development of adaptive resistance in Staphylococcus epidermidis RP62A.}, journal = {Journal of medical microbiology}, volume = {66}, number = {10}, pages = {1506-1515}, doi = {10.1099/jmm.0.000570}, pmid = {28893370}, issn = {1473-5644}, mesh = {Acyclic Monoterpenes ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; *Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Staphylococcus epidermidis/*drug effects/*physiology ; Terpenes/*pharmacology ; }, abstract = {PURPOSE: The current study has been designed to delineate the efficacy of geraniol (GE) on biofilm formation in Staphylococcus epidermidis as well as the effect of subinhibitory concentrations of GE on the development of adaptive resistance.

METHODOLOGY: Biofilm biomass quantification assay was performed to evaluate the antibiofilm activity of GE against S. epidermidis. Microscopic observation of biofilms and extracellular polymeric substance (EPS), slime and cell surface hydrophobicity (CSH) production were also studied to support the antibiofilm potential of GE. In addition, S. epidermidis was examined for its adaptive resistance development upon continuous exposure of GE at its subinhibitory concentrations.Results/Key findings. The MIC of GE against S. epidermidis was 512 µg ml[-1]. Without hampering the growth of the pathogen, GE at its sub-MICs (50, 100, 150 and 200 µg ml[-1]) exhibited a dose-dependent increase in antibiofilm activity. The minimal biofilm inhibitory concentration (MBIC) of GE was found to be 200 µg ml[-1] with a maximum biofilm inhibition of 85 %. Disintegrated biofilm architecture, reduced EPS, slime and CSH production validated the antibiofilm efficacy of GE. Although the action of GE on preformed biofilm is limited, a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay and live/dead cell staining method revealed reduction in the viability (47 %) of biofilm inhabitants at 2×MIC concentration. Sequential exposure of S. epidermidis to the sub-MICs of GE resulted in poor development of adaptive resistance with diminished biofilm formation.

CONCLUSION: The present study highlights the potential of GE as a suitable candidate for the control of biofilm-mediated S. epidermidis infections.}, } @article {pmid28892292, year = {2017}, author = {Wang, P and Zeng, Z and Wang, W and Wen, Z and Li, J and Wang, X}, title = {Dissemination and loss of a biofilm-related genomic island in marine Pseudoalteromonas mediated by integrative and conjugative elements.}, journal = {Environmental microbiology}, volume = {19}, number = {11}, pages = {4620-4637}, doi = {10.1111/1462-2920.13925}, pmid = {28892292}, issn = {1462-2920}, mesh = {Aquatic Organisms/genetics/growth & development ; Biofilms/*growth & development ; Conjugation, Genetic/genetics ; DNA Transposable Elements/*genetics ; DNA, Bacterial/*genetics ; Escherichia coli K12/genetics/growth & development ; Genomic Islands/*genetics ; Pseudoalteromonas/*genetics ; Pseudomonas aeruginosa/genetics/growth & development ; Shewanella/genetics/growth & development ; }, abstract = {Acquisition of genomic islands (GIs) plays a central role in the diversification and adaptation of bacteria. Some GIs can be mobilized in trans by integrative and conjugative elements (ICEs) or conjugative plasmids if the GIs carry specific transfer-related sequences. However, the transfer mechanism of GIs lacking such elements remains largely unexplored. Here, we investigated the transmissibility of a GI found in a coral-associated marine bacterium. This GI does not carry genes with transfer functions, but it carries four genes required for robust biofilm formation. Notably, this GI is inserted in the integration site for SXT/R391 ICEs. We demonstrated that acquisition of an SXT/R391 ICE results in either a tandem GI/ICE arrangement or the complete displacement of the GI. The GI displacement by the ICE greatly reduces biofilm formation. In contrast, the tandem integration of the ICE with the GI in cis allows the GI to hijack the transfer machinery of the ICE to excise, transfer and re-integrate into a new host. Collectively, our findings reveal that the integration of an ICE into a GI integration site enables rapid genome dynamics and a new mechanism by which SXT/R391 ICEs can augment genome plasticity.}, } @article {pmid28892140, year = {2017}, author = {Vergara, A and Normanno, G and Di Ciccio, P and Pedonese, F and Nuvoloni, R and Parisi, A and Santagada, G and Colagiorgi, A and Zanardi, E and Ghidini, S and Ianieri, A}, title = {Biofilm Formation and Its Relationship with the Molecular Characteristics of Food-Related Methicillin-Resistant Staphylococcus aureus (MRSA).}, journal = {Journal of food science}, volume = {82}, number = {10}, pages = {2364-2370}, doi = {10.1111/1750-3841.13846}, pmid = {28892140}, issn = {1750-3841}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; *Biofilms/drug effects ; Cattle ; Female ; Humans ; Methicillin/pharmacology ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/isolation & purification/*physiology ; Milk/*microbiology ; Staphylococcal Infections/*microbiology ; }, abstract = {UNLABELLED: The capability to produce biofilm is an important persistence and dissemination mechanism of some foodborne bacteria. This paper investigates the relationship between some molecular characteristics (SCCmec, ST, spa-type, agr-type, cna, sarA, icaA, icaD, clfA, fnbA, fnbB, hla, hlb) of 22 food-related methicillin-resistant Staphylococcus aureus (MRSA) strains and their ability to form biofilm on stainless steel and polystyrene. Five (22.7%, 5/22) strains were able to synthesize biofilm on polystyrene, and one of these (4.5%, 1/22) strains was also able to synthesize biofilm on stainless steel. The largest amount of biofilm was formed on polystyrene by 2 MRSA strains isolated from cows' milk, thus raising concern about the dairy industry. The majority of MRSA biofilm producers carried SCCmec type IVa, suggesting that the presence of SCCmecIVa and/or agr type III could be related to the ability to form biofilm. In conclusion, in order to achieve an acceptable level of food safety, Good Hygiene Practices should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA biofilm-producing strains in the food industry.

PRACTICAL APPLICATION: In this study, some assayed isolates of food-related MRSA demonstrated the capacity to form biofilm. Biofilm formation differed according to surface characteristics and MRSA strains. A relationship was observed between some molecular characteristics and the ability to form biofilms. Few studies have investigated the ability of MRSA to form biofilms, and the majority of these studies have investigated clinical aspects. This work was performed to investigate whether or not there is a difference between MRSA food isolates and MRSA clinical isolates in their ability to form biofilm. These initial findings could provide information that will contribute to a better understanding of these aspects.}, } @article {pmid28892134, year = {2018}, author = {Todhanakasem, T and Yodsanga, S and Sowatad, A and Kanokratana, P and Thanonkeo, P and Champreda, V}, title = {Inhibition analysis of inhibitors derived from lignocellulose pretreatment on the metabolic activity of Zymomonas mobilis biofilm and planktonic cells and the proteomic responses.}, journal = {Biotechnology and bioengineering}, volume = {115}, number = {1}, pages = {70-81}, doi = {10.1002/bit.26449}, pmid = {28892134}, issn = {1097-0290}, mesh = {Anti-Bacterial Agents/*metabolism ; Biotransformation/*drug effects ; Ethanol/*metabolism ; Fermentation ; Inhibitory Concentration 50 ; Lignin/*metabolism ; Proteome/analysis ; Zymomonas/*drug effects/growth & development/*metabolism ; }, abstract = {Lignocellulose pretreatment produces various toxic inhibitors that affect microbial growth, metabolism, and fermentation. Zymomonas mobilis is an ethanologenic microbe that has been demonstrated to have potential to be used in lignocellulose biorefineries for bioethanol production. Z. mobilis biofilm has previously exhibited high potential to enhance ethanol production by presenting a higher viable cell number and higher metabolic activity than planktonic cells or free cells when exposed to lignocellulosic hydrolysate containing toxic inhibitors. However, there has not yet been a systematic study on the tolerance level of Z. mobilis biofilm compared to planktonic cells against model toxic inhibitors derived from lignocellulosic material. We took the first insight into the concentration of toxic compound (formic acid, acetic acid, furfural, and 5-HMF) required to reduce the metabolic activity of Z. mobilis biofilm and planktonic cells by 25% (IC25), 50% (IC50), 75% (IC75), and 100% (IC100). Z. mobilis strains ZM4 and TISTR 551 biofilm were two- to three fold more resistant to model toxic inhibitors than planktonic cells. Synergetic effects were found in the presence of formic acid, acetic acid, furfural, and 5-HMF. The IC25 of Z. mobilis ZM4 biofilm and TISTR 551 biofilm were 57 mm formic acid, 155 mm acetic acid, 37.5 mm furfural and 6.4 mm 5-HMF, and 225 mm formic acid, 291 mm acetic acid, 51 mm furfural and 41 mm 5-HMF, respectively. There was no significant difference found between proteomic analysis of the stress response to toxic inhibitors of Z. mobilis biofilm and planktonic cells on ZM4. However, TISTR 551 biofilms exhibited two proteins (molecular chaperone DnaK and 50S ribosomal protein L2) that were up-regulated in the presence of toxic inhibitors. TISTR 551 planktonic cells possessed two types of protein in the group of 30S ribosomal proteins and motility proteins that were up-regulated.}, } @article {pmid28891420, year = {2019}, author = {Hu, X and Yang, L and Lai, X and Yao, Q and Chen, K}, title = {Influence of Al(III) on biofilm and its extracellular polymeric substances in sequencing batch biofilm reactors.}, journal = {Environmental technology}, volume = {40}, number = {1}, pages = {53-59}, doi = {10.1080/09593330.2017.1378268}, pmid = {28891420}, issn = {1479-487X}, mesh = {*Biofilms ; *Extracellular Polymeric Substance Matrix ; Polysaccharides ; Proteins ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {This paper presented the influence of Al(III) on biodegradability, micromorphology, composition and functional groups characteristics of the biofilm extracellular polymeric substances (EPS) during different growth phases. The sequencing batch biofilm reactors were developed to cultivate biofilms under different Al(III) dosages. The results elucidated that Al(III) affected biofilm development adversely at the beginning of biofilm growth, but promoted the biofilm mass and improved the biofilm activity with the growth of the biofilm. The micromorphological observation indicated that Al(III) led to a reduction of the filaments and promotion of the EPS secretion in growth phases of the biofilm, also Al(III) could promote microorganisms to form larger colonies for mature biofilm. Then, the analysis of EPS contents and components suggested that Al(III) could increase the protein (PN) of tightly bound EPS (TB-EPS) which alleviated the metal toxicity inhibition on the biofilm during the initial phases of biofilm growth. The biofilm could gradually adapt to the inhibition caused by Al(III) at the biofilm maturation moment. Finally, through the Fourier transform infrared spectroscopy, it was found that Al(III) was beneficial for the proliferation and secretion of TB-EPS functional groups, especially the functional groups of protein and polysaccharides.}, } @article {pmid28890520, year = {2017}, author = {Tassew, DD and Mechesso, AF and Park, NH and Song, JB and Shur, JW and Park, SC}, title = {Biofilm formation and determination of minimum biofilm eradication concentration of antibiotics in Mycoplasma hyopneumoniae.}, journal = {The Journal of veterinary medical science}, volume = {79}, number = {10}, pages = {1716-1720}, pmid = {28890520}, issn = {1347-7439}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Mycoplasma hyopneumoniae/*drug effects ; Pneumonia of Swine, Mycoplasmal/microbiology ; Swine ; }, abstract = {The study was aimed to investigate biofilm forming ability of Mycoplasma hyopneumoniae and to determine the minimum biofilm eradication concentrations of antibiotics. Biofilm forming ability of six strains of M. hyopneumoniae was examined using crystal violet staining on coverslips. The results demonstrated an apparent line of biofilm growth in 3 of the strains isolated from swine with confirmed cases of enzootic pneumonia. BacLight bacterial viability assay revealed that the majority of the cells were viable after 336 hr of incubation. Moreover, M. hyopneumoniae persists in the biofilm after being exposed to 10 fold higher concentration of antibiotics than the minimum inhibitory concentrations in planktonic cells. To the best of our knowledge, this is the first report of biofilm formation in M. hyopneumoniae. However, comprehensive studies on the mechanisms of biofilm formation are needed to combat swine enzootic pneumonia caused by resistant M. hyopneumoniae.}, } @article {pmid28890436, year = {2017}, author = {Walker, WT and Jackson, CL and Allan, RN and Collins, SA and Kelso, MJ and Rineh, A and Yepuri, NR and Nicholas, B and Lau, L and Johnston, D and Lackie, P and Faust, SN and Lucas, JSA and Hall-Stoodley, L}, title = {Primary ciliary dyskinesia ciliated airway cells show increased susceptibility to Haemophilus influenzae biofilm formation.}, journal = {The European respiratory journal}, volume = {50}, number = {3}, pages = {}, doi = {10.1183/13993003.00612-2017}, pmid = {28890436}, issn = {1399-3003}, support = {PB-PG-1215-20014/DH_/Department of Health/United Kingdom ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion ; Bacterial Proteins/metabolism ; Biofilms/growth & development ; Case-Control Studies ; Child ; Child, Preschool ; Cytokines/metabolism ; Epithelial Cells/*microbiology ; Female ; Haemophilus Infections/*physiopathology ; Haemophilus influenzae/pathogenicity/physiology ; Humans ; Kartagener Syndrome/*microbiology/physiopathology ; Male ; Middle Aged ; Nitric Oxide/*pharmacology ; Primary Cell Culture ; Young Adult ; }, abstract = {Non-typeable Haemophilus influenzae (NTHi) is the most common pathogen in primary ciliary dyskinesia (PCD) patients. We hypothesised that abnormal ciliary motility and low airway nitric oxide (NO) levels on airway epithelial cells from PCD patients might be permissive for NTHi colonisation and biofilm development.We used a primary epithelial cell co-culture model to investigate NTHi infection. Primary airway epithelial cells from PCD and non-PCD patients were differentiated to ciliation using an air-liquid interface culture and then co-cultured with NTHi.NTHi adherence was greater on PCD epithelial cells compared to non-PCD cells (p<0.05) and the distribution of NTHi on PCD epithelium showed more aggregated NTHi in biofilms (p<0.001). Apart from defective ciliary motility, PCD cells did not significantly differ from non-PCD epithelial cells in the degree of ciliation and epithelial integrity or in cytokine, LL-37 and NO production. Treatment of PCD epithelia using exogenous NO and antibiotic significantly reduced NTHi viability in biofilms compared with antibiotic treatment alone.Impaired ciliary function was the primary defect in PCD airway epithelium underlying susceptibility to NTHi biofilm development compared with non-PCD epithelium. Although NO responses were similar, use of targeted NO with antibiotics enhanced killing of NTHi in biofilms, suggesting a novel therapeutic approach.}, } @article {pmid28890234, year = {2017}, author = {Zhu, L and Li, Y and Carrera, CA and Chen, YC and Li, M and Fok, A}, title = {Calibration of a lactic-acid model for simulating biofilm-induced degradation of the dentin-composite interface.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {33}, number = {11}, pages = {1315-1323}, pmid = {28890234}, issn = {1879-0097}, support = {R01 DE021366/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Calibration ; Cattle ; Composite Resins/*chemistry ; Dental Leakage ; *Dental Restoration Failure ; Dental Restoration, Permanent ; Dentin/*chemistry/*microbiology ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Lactic Acid/*chemistry ; Materials Testing ; Microscopy, Electron, Scanning ; Silicon Dioxide/*chemistry ; Surface Properties ; X-Ray Microtomography ; Zirconium/*chemistry ; }, abstract = {OBJECTIVE: To verify and calibrate a chemical model for simulating the degradation of the dentin-composite interface induced by multi-species oral biofilms in vitro.

METHODS: Dentin-composite disks (5-mm dia.×2-mm thick) were made from bovine incisor roots and filled with either Z100™ (Z100) or Filtek™ LS (LS) composite. The disks, which were covered with nail varnish, but with one of the dentin-composite margins exposed, were immersed in lactic acid solution at pH 4.5 for up to 48h. Diametral compression was performed to measure the reduction in bond strength of the dentin-composite disks following acid challenge. Scanning electron microscopy (SEM) was used to examine decalcification of dentin and fracture modes of the disks. To better understand the degradation process, micro-computed tomography, in combination with a radiopaque dye (AgNO3), was used to assess interfacial leakage in 3D longitudinally, while SEM was used to determine the path of leakage. One-way analysis of variance (ANOVA) was used to analyze the results, with the level of statistical significance set at p<0.05. The results were compared with those obtained previously using multi-species biofilms for verification and calibration purposes.

RESULTS: After 48h of acid challenge, the debonding load of both the LS- and Z100-filled disks reduced significantly (p<0.05). In the Z100-filled disks, debonding mostly occurred at the adhesive-dentin interface, while in the LS-filled disks, this happened at the adhesive-composite interface, instead. The degree of dentin demineralization, the reduction in debonding load and the modes of failure observed were very similar to those induced by multi-species oral biofilms found in the previous work. Leakage of AgNO3 occurred mainly along the hybrid layer. The specimens filled with Z100 had a thicker hybrid layer (∼6.5μm), which exhibited more interfacial leakage than those filled with LS.

SIGNIFICANCE: The chemical model with lactic acid used in this study can induce degradation to the dentin-composite interface similar to those produced by multi-species biofilms. With appropriate calibration, this could provide an effective in vitro method for ageing composite restorations in assessing their potential clinical performance.}, } @article {pmid28889311, year = {2017}, author = {Opoku-Temeng, C and Sintim, HO}, title = {Targeting c-di-GMP Signaling, Biofilm Formation, and Bacterial Motility with Small Molecules.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1657}, number = {}, pages = {419-430}, doi = {10.1007/978-1-4939-7240-1_31}, pmid = {28889311}, issn = {1940-6029}, mesh = {Bacteria/*drug effects/*metabolism ; Bacterial Physiological Phenomena/*drug effects ; Bacterial Proteins/chemistry/metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/biosynthesis/metabolism ; Escherichia coli Proteins/metabolism ; Intracellular Space/metabolism ; Membrane Proteins/chemistry/metabolism ; Phosphoric Diester Hydrolases/metabolism ; Phosphorus-Oxygen Lyases/metabolism ; Protein Binding ; Protein Interaction Domains and Motifs ; Proteolysis ; Second Messenger Systems/*drug effects ; }, abstract = {Bacteria possess several signaling molecules that regulate distinct phenotypes. Cyclic di-GMP (c-di-GMP) has emerged as a ubiquitous second messenger that regulates bacterial virulence, cell cycle, motility, and biofilm formation. The link between c-di-GMP signaling and biofilm formation affords novel strategies for treatment of biofilm-associated infections, which is a major public health problem. The complex c-di-GMP signaling pathway creates a hurdle in the development of small molecule modulators. Nonetheless, some progress has been made in this regard and inhibitors of c-di-GMP metabolizing enzymes that affect biofilm formation and motility have been documented. Herein we discuss the components of c-di-GMP signaling, their correlation with biofilm formation as well as motility and reported small molecule inhibitors of c-di-GMP signaling.}, } @article {pmid28889242, year = {2018}, author = {Bhattacharyya, P and Agarwal, B and Goswami, M and Maiti, D and Baruah, S and Tribedi, P}, title = {Zinc oxide nanoparticle inhibits the biofilm formation of Streptococcus pneumoniae.}, journal = {Antonie van Leeuwenhoek}, volume = {111}, number = {1}, pages = {89-99}, doi = {10.1007/s10482-017-0930-7}, pmid = {28889242}, issn = {1572-9699}, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/*drug effects ; *Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Streptococcus pneumoniae/*drug effects/*physiology ; Zinc Oxide/*administration & dosage/chemistry ; }, abstract = {Biofilms are structured consortia of microbial cells that grow on living and non living surfaces and surround themselves with secreted polymers. Infections with bacterial biofilms have emerged as a foremost public health concern because biofilm growing cells can be highly resistant to both antibiotics and host immune defenses. Zinc oxide nanoparticles have been reported as a potential antimicrobial agent, thus, in the current study, we have evaluated the antimicrobial as well as antibiofilm activity of zinc oxide nanoparticles against the bacterium Streptococcus pneumoniae which is a significant cause of disease. Zinc oxide nanoparticles showed strong antimicrobial activity against S. pneumoniae, with an MIC value of 40 μg/ml. Biofilm inhibition of S. pneumoniae was also evaluated by performing a series of experiments such as crystal violet assay, microscopic observation, protein count, EPS secretion etc. using sub-MIC concentrations (3, 6 and 12 µg/ml) of zinc oxide nanoparticles. The results showed that the sub-MIC doses of zinc oxide nanoparticles exhibited significant anti-biofilm activity against S. pneumoniae, with maximum biofilm attenuation found at 12 μg/ml. Taken together, the results indicate that zinc oxide nanoparticles can be considered as a potential agent for the inhibition of microbial biofilms.}, } @article {pmid28889121, year = {2017}, author = {Skagia, A and Vezyri, E and Grados, K and Venieraki, A and Karpusas, M and Katinakis, P and Dimou, M}, title = {Structure-Function Analysis of the Periplasmic Escherichia coli Cyclophilin PpiA in Relation to Biofilm Formation.}, journal = {Journal of molecular microbiology and biotechnology}, volume = {27}, number = {4}, pages = {228-236}, doi = {10.1159/000478858}, pmid = {28889121}, issn = {1660-2412}, mesh = {Biofilms/*growth & development ; Cyclophilins/*chemistry/genetics/metabolism ; DNA Primers ; Escherichia coli/genetics/*metabolism ; Gene Expression Profiling ; Mutagenesis, Site-Directed ; Mutant Proteins/chemistry/metabolism ; Peptidylprolyl Isomerase/*chemistry/genetics ; Protein Conformation ; Recombinant Proteins/*chemistry/genetics ; }, abstract = {The presence of peptidyl-prolyl cis/trans isomerases (PPIases, EC: 5.2.1.8) in all domains of life indicates their biological importance. Cyclophilin PpiA, present in the periplasm of gram-negative bacteria, possesses PPIase activity but its physiological functions are still not clearly defined. Here, we demonstrate that the ΔppiA deletion strain from Escherichia coli exhibits an increased ability for biofilm formation and enhanced swimming motility compared to the wild-type strain. To identify structural features of PpiA which are necessary for the negative modulation of biofilm formation, we constructed a series of mutant PpiA proteins using a combination of error-prone and site-directed mutagenesis approaches. We show that the negative effect of PpiA on biofilm formation is not dependent on its PPIase activity, since PpiA mutants with a reduced PPIase activity are able to complement the ΔppiA strain during biofilm growth.}, } @article {pmid28887986, year = {2017}, author = {Lopes, FS and Oliveira, JR and Milani, J and Oliveira, LD and Machado, JPB and Trava-Airoldi, VJ and Lobo, AO and Marciano, FR}, title = {Biomineralized diamond-like carbon films with incorporated titanium dioxide nanoparticles improved bioactivity properties and reduced biofilm formation.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {81}, number = {}, pages = {373-379}, doi = {10.1016/j.msec.2017.07.043}, pmid = {28887986}, issn = {1873-0191}, mesh = {*Biofilms ; Carbon ; Coated Materials, Biocompatible ; Diamond ; Metal Nanoparticles ; Staphylococcus aureus ; Surface Properties ; Titanium ; }, abstract = {Recently, the development of coatings to protect biomedical alloys from oxidation, passivation and to reduce the ability for a bacterial biofilm to form after implantation has emerged. Diamond-like carbon films are commonly used for implanted medical due to their physical and chemical characteristics, showing good interactions with the biological environment. However, these properties can be significantly improved when titanium dioxide nanoparticles are included, especially to enhance the bactericidal properties of the films. So far, the deposition of hydroxyapatite on the film surface has been studied in order to improve biocompatibility and bioactive behavior. Herein, we developed a new route to obtain a homogeneous and crystalline apatite coating on diamond-like carbon films grown on 304 biomedical stainless steel and evaluated its antibacterial effect. For this purpose, films containing two different concentrations of titanium dioxide (0.1 and 0.3g/L) were obtained by chemical vapor deposition. To obtain the apatite layer, the samples were soaked in simulated body fluid solution for up to 21days. The antibacterial activity of the films was evaluated by bacterial eradication tests using Staphylococcus aureus biofilm. Scanning electron microscopy, X-ray diffraction, Raman scattering spectroscopy, and goniometry showed that homogeneous, crystalline, and hydrophilic apatite films were formed independently of the titanium dioxide concentration. Interestingly, the diamond-like films containing titanium dioxide and hydroxyapatite reduced the biofilm formation compared to controls. A synergism between hydroxyapatite and titanium dioxide that provided an antimicrobial effect against opportunistic pathogens was clearly observed.}, } @article {pmid28886554, year = {2017}, author = {Thuptimdang, P and Limpiyakorn, T and Khan, E}, title = {Dependence of toxicity of silver nanoparticles on Pseudomonas putida biofilm structure.}, journal = {Chemosphere}, volume = {188}, number = {}, pages = {199-207}, doi = {10.1016/j.chemosphere.2017.08.147}, pmid = {28886554}, issn = {1879-1298}, mesh = {Biofilms/drug effects/*growth & development ; Biomass ; Metal Nanoparticles/chemistry/*toxicity ; Microscopy, Confocal ; Pseudomonas putida/*drug effects ; Silver/chemistry/*toxicity ; }, abstract = {Susceptibility of biofilms with different physical structures to silver nanoparticles (AgNPs) was studied. Biofilms of Pseudomonas putida KT2440 were formed in batch conditions under different carbon sources (glucose, glutamic acid, and citrate), glucose concentrations (5 and 50 mM), and incubation temperatures (25 and 30 °C). The biofilms were observed using confocal laser scanning microscopy for their physical characteristics (biomass amount, thickness, biomass volume, surface to volume ratio, and roughness coefficient). The biofilms forming under different growth conditions exhibited different physical structures. The biofilm thickness and the roughness coefficient were found negatively and positively correlated with the biofilm susceptibility to AgNPs, respectively. The effect of AgNPs on biofilms was low (1-log reduction of cell number) when the biofilms had high biomass amount, high thickness, high biomass volume, low surface to volume ratio, and low roughness coefficient. Furthermore, the extracellular polymeric substance (EPS) stripping process was applied to confirm the dependence of susceptibility to AgNPs on the structure of biofilm. After the EPS stripping process, the biofilms forming under different conditions showed reduction in thickness and biomass volume, and increases in surface to volume ratio and roughness coefficient, which led to more biofilm susceptibility to AgNPs. The results of this study suggest that controlling the growth conditions to alter the biofilm physical structure is a possible approach to reduce the impact of AgNPs on biofilms in engineered and natural systems.}, } @article {pmid28885723, year = {2017}, author = {Ma, JS and Chen, SY and Lo, HH}, title = {Biofilm formation of beta-hemolytic group G Streptococcus dysgalactiae subspecies equisimilis isolates and its association with emm polymorphism.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {11}, pages = {1027-1032}, doi = {10.1111/apm.12746}, pmid = {28885723}, issn = {1600-0463}, mesh = {Antigens, Bacterial/*genetics ; Bacterial Outer Membrane Proteins/*genetics ; Bacterial Typing Techniques ; Biofilms/*drug effects/growth & development ; Carrier Proteins/*genetics ; Culture Media/chemistry/pharmacology ; Gene Expression ; Glucose/metabolism/*pharmacology ; Humans ; Polymorphism, Genetic ; Streptococcal Infections/epidemiology/microbiology ; Streptococcus/classification/*drug effects/*genetics/isolation & purification ; Taiwan/epidemiology ; }, abstract = {Biofilm formation has been well known as a determinant of bacterial virulence. Group G Streptococcus dysgalactiae subspecies equisimilis (SDSE), a relevant pathogen with increasing medical importance, was evaluated for the biofilm-forming potential. Microtiter plate assay was used to assess the most feasible medium for group G SDSE to form a biofilm. Among 246 SDSE isolates examined, 46.7%, 43.5%, 33.3%, and 26.4% of isolates showed moderate or strong biofilm-forming abilities using tryptic soy broth (TSB), brain heart infusion broth (BHI), Todd-Hewitt broth (THB), and C medium with 30 mM glucose (CMG), respectively. The addition of glucose significantly increased the biofilm-forming ability of group G SDSE. FCT (fibronectin-collagen-T-antigen) typing of SDSE was first undertaken and 11 FCT types were found. Positive associations of stG10.0 or negative associations of stG245.0, stG840.0, and stG6.1 with biofilm-forming ability of SDSE were, respectively, found. This was the first investigation demonstrating biofilm-forming potential in clinical group G SDSE isolates; also, some significant associations of biofilm-forming ability with certain emm types were presented.}, } @article {pmid28884578, year = {2017}, author = {Wang, J and Zhou, H and Guo, G and Tan, J and Wang, Q and Tang, J and Liu, W and Shen, H and Li, J and Zhang, X}, title = {Enhanced Anti-Infective Efficacy of ZnO Nanoreservoirs through a Combination of Intrinsic Anti-Biofilm Activity and Reinforced Innate Defense.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {39}, pages = {33609-33623}, doi = {10.1021/acsami.7b08864}, pmid = {28884578}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Mice ; Nanoparticles ; *Nanostructures ; Zinc Oxide ; }, abstract = {The increasing prevalence of implant-associated infections (IAIs) imposes a heavy burden on patients and medical providers. Bacterial biofilms are recalcitrant to antiseptic drugs and local immune defense and can attenuate host proinflammatory response to interfere with bacterial clearance. Zinc oxide nanoparticles (ZnO NPs) play a dual role in antibacterial and immunomodulatory activities but compromise the cytocompatibility because of their intracellular uptake. Here, ZnO NPs were immobilized on titanium to form homogeneous nanofilms (from discontinuous to continuous) through magnetron sputtering, and the possible antimicrobial activity and immunomodulatory effect of nano-ZnO films were investigated. Nano-ZnO films were found to prohibit sessile bacteria more than planktonic bacteria in vitro, and the antibacterial effect occurred in a dose-dependent manner. Using a novel mouse soft tissue IAI model, the in vivo results revealed that nano-ZnO films possessed outstanding antimicrobial efficacy, which could not be ascribed solely to the intrinsic anti-infective activity of nano-ZnO films observed in vitro. Macrophages and polymorphonuclear leukocytes (PMNs), two important factors in innate immune response, were cocultured with nano-ZnO and bacteria/lipopolysaccharide in vitro, and the nano-ZnO films could enhance the antimicrobial efficacy of macrophages and PMNs through promoting phagocytosis and secretion of inflammatory cytokines. This study provides insights into the anti-infective activity and mechanism of ZnO and consolidates the theoretical basis for future clinical applications of ZnO.}, } @article {pmid28884496, year = {2017}, author = {Vaughn, AR and Haas, KN and Burney, W and Andersen, E and Clark, AK and Crawford, R and Sivamani, RK}, title = {Potential Role of Curcumin Against Biofilm-Producing Organisms on the Skin: A Review.}, journal = {Phytotherapy research : PTR}, volume = {31}, number = {12}, pages = {1807-1816}, doi = {10.1002/ptr.5912}, pmid = {28884496}, issn = {1099-1573}, mesh = {Anti-Inflammatory Agents, Non-Steroidal/pharmacology/*therapeutic use ; Biofilms/*drug effects ; Curcumin/pharmacology/*therapeutic use ; Humans ; Skin/*pathology ; Skin Diseases/*drug therapy/pathology ; }, abstract = {Turmeric root (Curcuma longa) is predominantly used as a spice, but has also long been known to possess antimicrobial, analgesic, antiinflammatory, and anticancer properties. One predominant group of active compounds in turmeric are curcuminoids, namely bright yellow-pigmented curcumin. While modern science has yet to fully investigate the therapeutic claims of turmeric and its derivatives, results have proven promising in decreasing pain and inflammation in arthritis, improving insulin sensitivity in diabetes, and even curing a variety of infections. The purpose of this review is to discuss the potential for curcumin as an agent against microbial infections, with a special focus on the skin and in the development of bacterial biofilms. Curcumin has demonstrated bactericidal efficacy against a variety of infections when administered with antibiotics in several clinical studies, with consistent antimicrobial activity demonstrated in vitro, as well as in urinary tract infections, gingival infections, and chronic wound infections. Hypothesized mechanisms of action include curcumin's ability to perturb bacterial membranes, disturb protofillament assembly, and even impair bacterial virulence factors. Further investigation is needed to fully understand which organisms are most susceptible to the effects of curcumin and how curcumin can be implemented in dermatology to treat skin conditions such as chronic wounds and acne vulgaris. Copyright © 2017 John Wiley & Sons, Ltd.}, } @article {pmid28884270, year = {2018}, author = {Chonova, T and Labanowski, J and Cournoyer, B and Chardon, C and Keck, F and Laurent, É and Mondamert, L and Vasselon, V and Wiest, L and Bouchez, A}, title = {River biofilm community changes related to pharmaceutical loads emitted by a wastewater treatment plant.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {10}, pages = {9254-9264}, pmid = {28884270}, issn = {1614-7499}, mesh = {Biofilms/*drug effects ; Ecosystem ; Rivers/*chemistry ; Wastewater/*analysis/chemistry ; Water Pollutants, Chemical/*analysis/chemistry ; }, abstract = {Wastewater treatment plants (WWTP) are the main sources of a broad spectrum of pharmaceuticals found in freshwater ecosystems. These pollutants raise environmental health concerns because of their highly bioactive nature and their chronic releases. Despite this, pharmaceuticals' effects on aquatic environments are poorly defined. Biofilms represent a major part of the microbial life in rivers and streams. They can drive key metabolic cycles and their organizations reflect exposures to changing chemical, physical, and biological constraints. This study estimated the concentrations, over a 3-year period, of ten pharmaceuticals and five nutrients in a river contaminated by a conventional WWTP fed by urban and hospital wastewaters. Variations in these concentrations were related to biofilm bacterial community dynamics. Rock biofilms had developed over defined periods and were harvested at four locations in the river from the up- and downstream WWTP discharge point. Pharmaceuticals were found in all locations in concentrations ranging from not being detected to 192 ng L[-1]. Despite the high dilution factor of the WWTP effluents by the receiving river, pharmaceuticals were found more concentrated downstream than upstream the WWTP. Shifts in bacterial community structures linked to the environmental emission of pharmaceuticals were superior to seasonal community changes. A community structure from a site located downstream but close to the WWTP was more strongly associated with high pharmaceutical loads and different from those of biofilm samples from the WWTP upstream or far downstream sites. These latter sites were more strongly associated with high nutrient contents. Low environmental concentrations of pharmaceuticals can thus be transferred from WWTP effluents to a connected stream and induce bacterial aquatic community changes over time.}, } @article {pmid28883986, year = {2017}, author = {Gomez-Carretero, S and Libberton, B and Rhen, M and Richter-Dahlfors, A}, title = {Redox-active conducting polymers modulate Salmonella biofilm formation by controlling availability of electron acceptors.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {19}, pmid = {28883986}, issn = {2055-5008}, abstract = {Biofouling is a major problem caused by bacteria colonizing abiotic surfaces, such as medical devices. Biofilms are formed as the bacterial metabolism adapts to an attached growth state. We studied whether bacterial metabolism, hence biofilm formation, can be modulated in electrochemically active surfaces using the conducting conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT). We fabricated composites of PEDOT doped with either heparin, dodecyl benzene sulfonate or chloride, and identified the fabrication parameters so that the electrochemical redox state is the main distinct factor influencing biofilm growth. PEDOT surfaces fitted into a custom-designed culturing device allowed for redox switching in Salmonella cultures, leading to oxidized or reduced electrodes. Similarly large biofilm growth was found on the oxidized anodes and on conventional polyester. In contrast, biofilm was significantly decreased (52-58%) on the reduced cathodes. Quantification of electrochromism in unswitched conducting polymer surfaces revealed a bacteria-driven electrochemical reduction of PEDOT. As a result, unswitched PEDOT acquired an analogous electrochemical state to the externally reduced cathode, explaining the similarly decreased biofilm growth on reduced cathodes and unswitched surfaces. Collectively, our findings reveal two opposing effects affecting biofilm formation. While the oxidized PEDOT anode constitutes a renewable electron sink that promotes biofilm growth, reduction of PEDOT by a power source or by bacteria largely suppresses biofilm formation. Modulating bacterial metabolism using the redox state of electroactive surfaces constitutes an unexplored method with applications spanning from antifouling coatings and microbial fuel cells to the study of the role of bacterial respiration during infection.}, } @article {pmid28883911, year = {2017}, author = {Shrestha, LB and Bhattarai, NR and Khanal, B}, title = {Antibiotic resistance and biofilm formation among coagulase-negative staphylococci isolated from clinical samples at a tertiary care hospital of eastern Nepal.}, journal = {Antimicrobial resistance and infection control}, volume = {6}, number = {}, pages = {89}, pmid = {28883911}, issn = {2047-2994}, abstract = {BACKGROUND: Coagulase negative staphylococci were long regarded non-pathogenic as they are the commensals of human skin and mucosa but the recent changes in the medical practice and changes in underlying host populations, they are being considered significant pathogens associated with number of nosocomial infections. The objective of the study was to determine the species, antimicrobial susceptibility pattern, biofilm forming ability of the clinically significant CoNS isolates and to compare the different methods for the detection of biofilm formation.

METHODS: A total of 52 clinically significant CoNS isolates obtained from different units during a year period were studied. Characterization was done using standard microbiological guidelines and antimicrobial susceptibility was done following CLSI guidelines. Biofilm formation was detected by using three methods i.e. tissue culture plate method, congo red agar method and tube adherence method.

RESULTS: Among 52 isolates, S. epidermidis (52%) was the most common species which was followed by S. saprophyticus (18%) and S. haemolyticus (14%). Antimicrobial susceptibility pattern of CoNS documented resistance of 80% to ampicillin. Resistance to cefoxitin and ceftriaxone was observed in 58% of the isolates. Biofilm formation was observed in 65.38% of the isolates. The accuracy of Congo red agar and tube adherence method for the detection of biofilm formation was 82% and 76% respectively.

CONCLUSION: CoNS isolates obtained from clinical samples should be processed routinely and antimicrobial susceptibility testing should be performed. Multidrug-resistant CoNS are prevalent. All the three methods i.e. tissue culture plate, Congo red agar and tube adherence method can be used in detecting biofilm formation.}, } @article {pmid28883818, year = {2017}, author = {Gutiérrez, D and Fernández, L and Martínez, B and Ruas-Madiedo, P and García, P and Rodríguez, A}, title = {Real-Time Assessment of Staphylococcus aureus Biofilm Disruption by Phage-Derived Proteins.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1632}, pmid = {28883818}, issn = {1664-302X}, abstract = {A current focus of research is the development of new tools for removing bacterial biofilms in industrial settings. Bacteriophage-encoded proteins, such as endolysins, virion-associated peptidoglycan hydrolases, and exopolysaccharide depolymerases, have been shown to be efficient against these structures. However, the current screening techniques for the identification of antibiofilm properties of phage-derived proteins have important shortcomings. The aim of this work was to use the rapid, reproducible and accurate technology "real-time cell analyzer" for screening and comparing the antibiofilm ability of four phage-derived compounds, three lytic proteins (LysH5, CHAP-SH3b, and HydH5-SH3b) and one exopolysaccharide depolymerase (Dpo7) against Staphylococcus aureus biofilms, which have been associated with recurrent contamination of food products. The data generated after biofilm treatment allowed for the calculation of different antibiofilm parameters: (1) the minimum biofilm eradicating concentration that removes 50% of the biofilm (ranging from 3.5 ± 1.1 to 6.6 ± 0.5 μM), (2) the lowest concentration needed to observe an antibiofilm effect (∼1.5 μM for all the proteins), and (3) the specific antibiofilm activity and the percentage of biofilm removal that revealed LysH5 as the best antibiofilm compound. Overall, this technology might be used to quickly assess and compare by standardized parameters the disaggregating activity of phage antibiofilm proteins.}, } @article {pmid28882736, year = {2018}, author = {Anupama, R and Mukherjee, A and Babu, S}, title = {Gene-centric metegenome analysis reveals diversity of Pseudomonas aeruginosa biofilm gene orthologs in fresh water ecosystem.}, journal = {Genomics}, volume = {110}, number = {2}, pages = {89-97}, doi = {10.1016/j.ygeno.2017.08.010}, pmid = {28882736}, issn = {1089-8646}, mesh = {*Biofilms ; Fresh Water/microbiology ; *Genes, Bacterial ; *Genetic Variation ; *Metagenome ; Microbiota ; Pseudomonas aeruginosa/*genetics/physiology ; }, abstract = {Metagenomic analysis of biofilm forming bacteria in environmental samples remains challenging due to the non-availability of gene sequences of most of the uncultivable bacteria. Sequences of Pseudomonas aeruginosa PAO1-UW genes involved either directly or indirectly in biofilm formation were analyzed using BLASTn to obtain matching sequences from different strain, species and genus. Conserved regions in the functional domain of the amino acid sequences were used to design common primers for direct PCR analysis of freshwater metagenomes. Seven key genes such as aceA, clpP, typA, cbrA, phoR, rpoS and gacA involved in biofilm formation were validated. The ortholog genes belonged to wide range of Pseudomonas sp. indicating the diversity of biofilm genes and the conservation of protein functional domains. The approach would also help in analyzing the expression of biofilm genes in different bacteria of freshwater systems for monitoring toxic contaminations such as organic or inorganic pollutants.}, } @article {pmid28881210, year = {2017}, author = {Ontiveros-Valencia, A and Zhou, C and Ilhan, ZE and de Saint Cyr, LC and Krajmalnik-Brown, R and Rittmann, BE}, title = {Total electron acceptor loading and composition affect hexavalent uranium reduction and microbial community structure in a membrane biofilm reactor.}, journal = {Water research}, volume = {125}, number = {}, pages = {341-349}, doi = {10.1016/j.watres.2017.08.060}, pmid = {28881210}, issn = {1879-2448}, mesh = {Bacteria/genetics ; Biofilms ; Bioreactors/*microbiology ; Cytochrome c Group ; Electrons ; Nitrates/chemistry/metabolism ; Oxidants/chemistry/metabolism ; Oxidation-Reduction ; Sulfates/chemistry/metabolism ; Uranium/analysis/*chemistry ; Water Purification/methods ; }, abstract = {Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales. Though potentially competing for electrons with U(VI) reducers, homo-acetogens helped attain steady U(VI) reduction, while methanogenesis inhibited U(VI) reduction. U(VI) reduction was reinstated through suppression of methanogenesis by addition of bromoethanesulfonate or by competition from SRB when sulfate was re-introduced. Predictive metagenome analysis further points out community changes in response to alterations in the electron-acceptor loading: Sporulation and homo-acetogenesis were critical factors for strengthening stable microbial U(VI) reduction. This study documents that sporulation was important to long-term U(VI) reduction, whether or not microorganisms that carry out U(VI) reduction mediated by cytochrome c3, such as SRB and ferric-iron-reducers, were inhibited.}, } @article {pmid28878520, year = {2017}, author = {Singh, AK and Prakash, P and Achra, A and Singh, GP and Das, A and Singh, RK}, title = {Standardization and Classification of In vitro Biofilm Formation by Clinical Isolates of Staphylococcus aureus.}, journal = {Journal of global infectious diseases}, volume = {9}, number = {3}, pages = {93-101}, pmid = {28878520}, issn = {0974-777X}, abstract = {BACKGROUND: Staphylococcus aureus is Gram-positive bacterium commonly associated with nosocomial infections. The development of biofilm exhibiting drug resistance especially in foreign body associated infections has enabled the bacterium to draw considerable attention. However, till date, consensus guidelines for in vitro biofilm quantitation and categorization criterion for the bacterial isolates based on biofilm-forming capacity are lacking. Therefore, it was intended to standardize in vitro biofilm formation by clinical isolates of S. aureus and then to classify them on the basis of their biofilm-forming capacity.

MATERIALS AND METHODS: A study was conducted for biofilm quantitation by tissue culture plate (TCP) assay employing 61 strains of S. aureus isolated from clinical samples during May 2015- December 2015 wherein several factors influencing the biofilm formation were optimized. Therefore, it was intended to propose a biofilm classification criteria based on the standard deviation multiples of the control differentiating them into non, low, medium, and high biofilm formers.

RESULTS: Brain-heart infusion broth was found to be more effective in biofilm formation compared to trypticase soy broth. Heat fixation was more effective than chemical fixation. Although, individually, glucose, sucrose, and sodium chloride (NaCl) had no significant effect on biofilm formation, a statistically significant increase in absorbance was observed after using the supplement mix consisting of 222.2 mM glucose, 116.9 mM sucrose, and 1000 mM NaCl (P= 0.037).

CONCLUSIONS: The present study puts forth a standardized in vitro TCP assay for biofilm biomass quantitation and categorization criteria for clinical isolates of S. aureus based on their biofilm-forming capacity. The proposed in vitro technique may be further evaluated for its usefulness in the management of persistent infections caused by the bacterium.}, } @article {pmid28878519, year = {2017}, author = {Dastranj, M and Farahani, A and Shoja, S and Dinarvand, G}, title = {State of Globe: Biofilm Formation in Staphylococcus aureus Isolates.}, journal = {Journal of global infectious diseases}, volume = {9}, number = {3}, pages = {91-92}, pmid = {28878519}, issn = {0974-777X}, } @article {pmid28878230, year = {2017}, author = {Sierra, EM and Pereira, MR and Maester, TC and Gomes-Pepe, ES and Mendoza, ER and Lemos, EGM}, title = {Halotolerant aminopeptidase M29 from Mesorhizobium SEMIA 3007 with biotechnological potential and its impact on biofilm synthesis.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {10684}, pmid = {28878230}, issn = {2045-2322}, mesh = {Amino Acid Sequence ; Aminopeptidases/*chemistry/genetics/metabolism/*pharmacology ; Biofilms/*drug effects ; Enzyme Activation ; Evolution, Molecular ; Genome, Bacterial ; Genomics/methods ; Mesorhizobium/*metabolism ; Protein Multimerization ; Quantitative Structure-Activity Relationship ; Recombinant Proteins/chemistry/genetics ; Sequence Analysis, DNA ; Solutions ; }, abstract = {The aminopeptidase gene from Mesorhizobium SEMIA3007 was cloned and overexpressed in Escherichia coli. The enzyme called MesoAmp exhibited optimum activity at pH 8.5 and 45 °C and was strongly activated by Co[2+] and Mn[2+]. Under these reaction conditions, the enzyme displayed Km and kcat values of 0.2364 ± 0.018 mM and 712.1 ± 88.12 s[-1], respectively. Additionally, the enzyme showed remarkable stability in organic solvents and was active at high concentrations of NaCl, suggesting that the enzyme might be suitable for use in biotechnology. MesoAmp is responsible for 40% of the organism's aminopeptidase activity. However, the enzyme's absence does not affect bacterial growth in synthetic broth, although it interfered with biofilm synthesis and osmoregulation. To the best of our knowledge, this report describes the first detailed characterization of aminopeptidase from Mesorhizobium and suggests its importance in biofilm formation and osmotic stress tolerance. In summary, this work lays the foundation for potential biotechnological applications and/or the development of environmentally friendly technologies and describes the first solvent- and halo-tolerant aminopeptidases identified from the Mesorhizobium genus and its importance in bacterial metabolism.}, } @article {pmid28876402, year = {2017}, author = {Lima, JLDC and Alves, LR and Paz, JNPD and Rabelo, MA and Maciel, MAV and Morais, MMC}, title = {Analysis of biofilm production by clinical isolates of Pseudomonas aeruginosa from patients with ventilator-associated pneumonia.}, journal = {Revista Brasileira de terapia intensiva}, volume = {29}, number = {3}, pages = {310-316}, pmid = {28876402}, issn = {1982-4335}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms ; Bronchoalveolar Lavage Fluid/microbiology ; Humans ; Microbial Sensitivity Tests ; Pneumonia, Ventilator-Associated/*microbiology ; Pseudomonas Infections/*epidemiology/microbiology ; Pseudomonas aeruginosa/drug effects/*isolation & purification ; Respiration, Artificial ; }, abstract = {OBJECTIVE: To phenotypically evaluate biofilm production by Pseudomonas aeruginosa clinically isolated from patients with ventilator-associated pneumonia.

METHODS: Twenty clinical isolates of P. aeruginosa were analyzed, 19 of which were from clinical samples of tracheal aspirate, and one was from a bronchoalveolar lavage sample. The evaluation of the capacity of P. aeruginosa to produce biofilm was verified using two techniques, one qualitative and the other quantitative.

RESULTS: The qualitative technique showed that only 15% of the isolates were considered biofilm producers, while the quantitative technique showed that 75% of the isolates were biofilm producers. The biofilm isolates presented the following susceptibility profile: 53.3% were multidrug-resistant, and 46.7% were multidrug-sensitive.

CONCLUSION: The quantitative technique was more effective than the qualitative technique for the detection of biofilm production. For the bacterial population analyzed, biofilm production was independent of the susceptibility profile of the bacteria, demonstrating that the therapeutic failure could be related to biofilm production, as it prevented the destruction of the bacteria present in this structure, causing complications of pneumonia associated with mechanical ventilation, including extrapulmonary infections, and making it difficult to treat the infection.}, } @article {pmid28874373, year = {2017}, author = {Kolpen, M and Lerche, CJ and Kragh, KN and Sams, T and Koren, K and Jensen, AS and Line, L and Bjarnsholt, T and Ciofu, O and Moser, C and Kühl, M and Høiby, N and Jensen, PØ}, title = {Hyperbaric Oxygen Sensitizes Anoxic Pseudomonas aeruginosa Biofilm to Ciprofloxacin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {11}, pages = {}, pmid = {28874373}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; *Hyperbaric Oxygenation ; Oxygen/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {Chronic Pseudomonas aeruginosa lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm, which is subject to strong oxygen (O2) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biofilms remain unclear, but accumulating evidence suggests that the efficacy of several bactericidal antibiotics is enhanced by stimulation of aerobic respiration of pathogens, while lack of O2 increases their tolerance. In fact, the bactericidal effect of several antibiotics depends on active aerobic metabolism activity and the endogenous formation of reactive O2 radicals (ROS). In this study, we aimed to apply hyperbaric oxygen treatment (HBOT) to sensitize anoxic P. aeruginosa agarose biofilms established to mimic situations with intense O2 consumption by the host response in the cystic fibrosis (CF) lung. Application of HBOT resulted in enhanced bactericidal activity of ciprofloxacin at clinically relevant durations and was accompanied by indications of restored aerobic respiration, involvement of endogenous lethal oxidative stress, and increased bacterial growth. The findings highlight that oxygenation by HBOT improves the bactericidal activity of ciprofloxacin on P. aeruginosa biofilm and suggest that bacterial biofilms are sensitized to antibiotics by supplying hyperbaric O2.}, } @article {pmid28871863, year = {2017}, author = {Cordeiro, RA and Serpa, R and Mendes, PBL and Evangelista, AJJ and Andrade, ARC and Franco, JDS and Pereira, VDS and Alencar, LP and Oliveira, JS and Camargo, ZP and Lima Neto, RG and Castelo-Branco, DSCM and Brilhante, RSN and Rocha, MFG and Sidrim, JJC}, title = {The HIV aspartyl protease inhibitor ritonavir impairs planktonic growth, biofilm formation and proteolytic activity in Trichosporon spp.}, journal = {Biofouling}, volume = {33}, number = {8}, pages = {640-650}, doi = {10.1080/08927014.2017.1350947}, pmid = {28871863}, issn = {1029-2454}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Interactions ; HIV Protease Inhibitors/*pharmacology ; Microbial Sensitivity Tests ; Peptide Hydrolases/metabolism ; Plankton/*drug effects/growth & development/metabolism ; Ritonavir/*pharmacology ; Trichosporon/*drug effects/growth & development/metabolism ; }, abstract = {This study evaluated the effect of the protease inhibitor ritonavir (RIT) on Trichosporon asahii and Trichosporon inkin. Susceptibility to RIT was assessed by the broth microdilution assay and the effect of RIT on protease activity was evaluated using azoalbumin as substrate. RIT was tested for its anti-biofilm properties and RIT-treated biofilms were assessed regarding protease activity, ultrastructure and matrix composition. In addition, antifungal susceptibility, surface hydrophobicity and biofilm formation were evaluated after pre-incubation of planktonic cells with RIT for 15 days. RIT (200 μg ml[-1]) inhibited Trichosporon growth. RIT (100 μg ml[-1]) also reduced protease activity of planktonic and biofilm cells, decreased cell adhesion and biofilm formation, and altered the structure of the biofilm and the protein composition of the biofilm matrix. Pre-incubation with RIT (100 μg ml[-1]) increased the susceptibility to amphotericin B, and reduced surface hydrophobicity and cell adhesion. These results highlight the importance of proteases as promising therapeutic targets and reinforce the antifungal potential of protease inhibitors.}, } @article {pmid28871227, year = {2017}, author = {Xu, CG and Yang, YB and Zhou, YH and Hao, MQ and Ren, YZ and Wang, XT and Chen, JQ and Muhammad, I and Wang, S and Liu, D and Li, XB and Li, YH}, title = {Comparative Proteomic Analysis Provides insight into the Key Proteins as Possible Targets Involved in Aspirin Inhibiting Biofilm Formation of Staphylococcus xylosus.}, journal = {Frontiers in pharmacology}, volume = {8}, number = {}, pages = {543}, pmid = {28871227}, issn = {1663-9812}, abstract = {Staphylococcus xylosus is an opportunistic pathogen that causes infection in humans and cow mastitis. And S. xylosus possesses a strong ability to form biofilms in vitro. As biofilm formation facilitates resistance to antimicrobial agents, the discovery of new medicinal properties for classic drugs is highly desired. Aspirin, which is the most common active component of non-steroidal anti-inflammatory compounds, affects the biofilm-forming capacity of various bacterial species. We have found that aspirin effectively inhibits biofilm formation of S. xylosus by Crystal violet (CV) staining and scanning electron microscopy analyses. The present study sought to elucidate possible targets of aspirin in suppressing S. xylosus biofilm formation. Based on an isobaric tag for relative and absolute quantitation (iTRAQ) fold-change of >1.2 or <0.8 (P-value < 0.05), 178 differentially expressed proteins, 111 down-regulated and 67 up-regulated, were identified after application of aspirin to cells at a 1/2 minimal inhibitory concentration. Gene ontology analysis indicated enrichment in metabolic processes for the majority of the differentially expressed proteins. We then used the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database to analyze a large number of differentially expressed proteins and identified genes involved in biosynthesis of amino acids pathway, carbon metabolism (pentose phosphate and glycolytic pathways, tricarboxylic acid cycle) and nitrogen metabolism (histidine metabolism). These novel proteins represent candidate targets in aspirin-mediated inhibition of S. xylosus biofilm formation at sub-MIC levels. The findings lay the foundation for further studies to identify potential aspirin targets.}, } @article {pmid28870772, year = {2017}, author = {Dall, GF and Tsang, STJ and Gwynne, PJ and Wilkinson, AJ and Simpson, AHRW and Breusch, SJB and Gallagher, MP}, title = {The dissolvable bead: A novel in vitro biofilm model for evaluating antimicrobial resistance.}, journal = {Journal of microbiological methods}, volume = {142}, number = {}, pages = {46-51}, doi = {10.1016/j.mimet.2017.08.020}, pmid = {28870772}, issn = {1872-8359}, mesh = {Alginates/chemistry ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Cryoelectron Microscopy ; Drug Resistance, Bacterial/*physiology ; Enterococcus faecalis/growth & development/isolation & purification ; Escherichia coli/growth & development/isolation & purification ; Gentamicins/*pharmacology ; Glucuronic Acid/chemistry ; Hexuronic Acids/chemistry ; Humans ; Klebsiella pneumoniae/growth & development/isolation & purification ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Pseudomonas aeruginosa/growth & development/isolation & purification ; Staphylococcus aureus/growth & development/isolation & purification ; Streptococcus mutans/growth & development/isolation & purification ; }, abstract = {In vitro biofilm assays are a vital first step in the assessment of therapeutic effectiveness. Current biofilm models have been found to be limited by throughput, reproducibility, and cost. We present a novel in vitro biofilm model, utilising a sodium alginate substratum for surface biofilm colony formation, which can be readily dissolved for accurate evaluation of viable organisms. The dissolving bead biofilm assay was evaluated using a range of clinically relevant strains. The reproducibility and responsiveness of the assay to an antimicrobial challenge was assessed using standardised methods. Cryo-scanning electron microscopy was used to image biofilm colonies. Biofilms were grown for 20h prior to testing. The model provides a reproducible and responsive assay to clinically-relevant antimicrobial challenges, as defined by established guidelines. Moreover cryo-scanning electron microscopy demonstrates that biofilm formation is localised exclusively to the alginate bead surface. Our results suggest that this simple model provides a robust and adaptable assay for the investigation of bacterial biofilms.}, } @article {pmid28870288, year = {2017}, author = {Liu, H and Xiao, Y and Nie, H and Huang, Q and Chen, W}, title = {Influence of (p)ppGpp on biofilm regulation in Pseudomonas putida KT2440.}, journal = {Microbiological research}, volume = {204}, number = {}, pages = {1-8}, doi = {10.1016/j.micres.2017.07.003}, pmid = {28870288}, issn = {1618-0623}, mesh = {Adhesins, Bacterial/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; DNA, Bacterial ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Guanosine Pentaphosphate/genetics/*pharmacology/*physiology ; Operon/genetics ; Polysaccharides, Bacterial/genetics/metabolism ; Pseudomonas putida/genetics/*metabolism ; Sequence Deletion ; Sigma Factor/genetics/metabolism ; Trans-Activators/genetics/metabolism ; beta-Galactosidase/metabolism ; }, abstract = {The global regulatory molecule (p)ppGpp is synthesized under limited nutrition conditions and involves in many cellular processes in bacteria. (p)ppGpp has been reported to affect biofilm formation in several bacterial species. Here, we found that deletion of (p)ppGpp synthase genes of Pseudomonas putida KT2440 led to enhanced biofilm formation in polystyrene microtitre plates. Besides, the pellicle of this mutant formed at the air-liquid interface lost the robust structure and became frail. The biofilm formation and its structure are mainly determined by exopolysaccharides (EPSs) and adhesins. Transcriptional analysis of four EPS operons designated as pea, peb, alg and bcs and two adhesin genes nominated as lapA and lapF showed that the deletion of (p)ppGpp synthase genes increased the expression of peb, bcs and lapA but repressed the expression of pea and lapF. Furthermore, expression of the regulation factor FleQ was significantly augmented in (p)ppGpp-synthase mutants while the expression of sigma factor RpoS was reduced. Since FleQ and RpoS play important roles in regulating expression of EPS and adhesin genes, (p)ppGpp may mediate the synthesis of biofilm matrix via influencing these regulators to control the biofilm formation and pellicle structure.}, } @article {pmid28870004, year = {2017}, author = {Jung, GH and Lim, ES and Woo, MA and Lee, JY and Kim, JS and Paik, HD}, title = {Inverse Correlation between Extracellular DNase Activity and Biofilm Formation among Chicken-Derived Campylobacter Strains.}, journal = {Journal of microbiology and biotechnology}, volume = {27}, number = {11}, pages = {1942-1951}, doi = {10.4014/jmb.1703.03052}, pmid = {28870004}, issn = {1738-8872}, mesh = {Animals ; Bacterial Proteins/analysis ; Biofilms/*growth & development ; Campylobacter/genetics/*isolation & purification/*metabolism ; Campylobacter coli/genetics/isolation & purification/metabolism ; Campylobacter jejuni/genetics/isolation & purification/metabolism ; Carbohydrates/analysis ; Chickens/*microbiology ; Coculture Techniques ; DNA, Bacterial/analysis ; Deoxyribonucleases/*metabolism ; Genome, Bacterial ; Microscopy, Confocal ; }, abstract = {Campylobacter jejuni and Campylobacter coli are important foodborne pathogenic bacteria, particularly in poultry meat. In this study, the presence of extracellular DNase activity was investigated for biofilm-deficient Campylobacter strains versus biofilm-forming Campylobacter strains isolated from chickens, to understand the relationship between extracellular DNase activity and biofilm formation. A biofilm-forming reference strain, C. jejuni NCTC11168, was co-incubated with biofilm non-forming strains isolated from raw chickens or their supernatants. The biofilm non-forming strains or supernatants significantly prohibited the biofilm formation of C. jejuni NCTC11168. In addition, the strains degraded pre-formed biofilms of C. jejuni NCTC11168. Degradation of C. jejuni NCTC11168 biofilm was confirmed after treatment with the supernatant of the biofilm non-forming strain 2-1 by confocal laser scanning microscopy. Quantitative analysis of the biofilm matrix revealed reduction of extracellular DNA (16%) and proteins (8.7%) after treatment. Whereas the biofilm-forming strains C. jejuni Y23-5 and C. coli 34-3 isolated from raw chickens and the C. jejuni NCTC11168 reference strain showed no extracellular DNase activity against their own genomic DNA, most biofilm non-forming strains tested, including C. jejuni 2-1, C. coli 34-1, and C. jejuni 63-1, exhibited obvious extracellular DNase activities against their own or 11168 genomic DNA, except for one biofilm non-former, C. jejuni 22-1. Our results suggest that extracellular DNase activity is a common feature suppressing biofilm formation among biofilm non-forming C. jejuni or C. coli strains of chicken origin.}, } @article {pmid28869803, year = {2017}, author = {Mawang, CI and Lim, YY and Ong, KS and Muhamad, A and Lee, SM}, title = {Identification of α-tocopherol as a bioactive component of Dicranopteris linearis with disrupting property against preformed biofilm of Staphylococcus aureus.}, journal = {Journal of applied microbiology}, volume = {123}, number = {5}, pages = {1148-1159}, doi = {10.1111/jam.13578}, pmid = {28869803}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Ferns/*chemistry ; Humans ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Plant Leaves/chemistry ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/physiology ; alpha-Tocopherol/chemistry/isolation & purification/*pharmacology ; }, abstract = {AIMS: The potential of Dicranopteris linearis leaves' extract and its bioactive components were investigated for the first time for its disrupting ability against Staphylococcus aureus biofilms.

METHODS AND RESULTS: The leaves of D. linearis were subjected to sonication-assisted extraction using hexane (HEX), dichloromethane, ethyl acetate and methanol (MeOH). It was found that only the MeOH fraction exhibited antimicrobial activity using broth microdilution assay; while all four fractions do not exhibit biofilm inhibition activity against S. aureusATCC 6538P, S. aureusATCC 43300, S. aureusATCC 33591 and S. aureusATCC 29213 using crystal violet assay. Among the four fractions tested, only the HEX fraction showed biofilm disrupting ability, with 60-90% disruption activity at 5 mg ml[-1] against all four S. aureus strains tested. Bioassay-guided purification of the active fraction has led to the isolation of α-tocopherol. α-Tocopherol does not affect the cells within the biofilms but instead affects the biofilm matrix in order to disrupt S. aureus biofilms.

CONCLUSIONS: α-Tocopherol was identified to be the bioactive component of D. linearis with disruption activity against S. aureus biofilm matrix.

The use of α-tocopherol as a biofilm disruptive agent might potentially be useful to treat biofilm-associated infections in the future.}, } @article {pmid28869408, year = {2017}, author = {Aynapudi, J and El-Rami, F and Ge, X and Stone, V and Zhu, B and Kitten, T and Xu, P}, title = {Involvement of signal peptidase I in Streptococcus sanguinis biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {9}, pages = {1306-1318}, pmid = {28869408}, issn = {1465-2080}, support = {R01 DE023078/DE/NIDCR NIH HHS/United States ; P30 NS047463/NS/NINDS NIH HHS/United States ; R01 DE018138/DE/NIDCR NIH HHS/United States ; S10 RR022495/RR/NCRR NIH HHS/United States ; P30 CA016059/CA/NCI NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Computational Biology/methods ; Cues ; Data Mining/methods ; Databases, Genetic ; Gene Expression Profiling ; Membrane Proteins/*genetics/*metabolism ; Mutation ; Proteomics/methods ; Serine Endopeptidases/*genetics/*metabolism ; Streptococcus sanguis/*physiology/ultrastructure ; }, abstract = {Biofilm accounts for 65-80 % of microbial infections in humans. Considerable evidence links biofilm formation by oral microbiota to oral disease and consequently systemic infections. Streptococcus sanguinis, a Gram-positive bacterium, is one of the most abundant species of the oral microbiota and it contributes to biofilm development in the oral cavity. Due to its altered biofilm formation, we investigated a biofilm mutant, ΔSSA_0351, that is deficient in type I signal peptidase (SPase) in this study. Although the growth curve of the ΔSSA_0351 mutant showed no significant difference from that of the wild-type strain SK36, biofilm assays using both microtitre plate assay and confocal laser scanning microscopy (CLSM) confirmed a sharp reduction in biofilm formation in the mutant compared to the wild-type strain and the paralogous mutant ΔSSA_0849. Scanning electron microscopy (SEM) revealed remarkable differences in the cell surface morphologies and chain length of the ΔSSA_0351 mutant compared with those of the wild-type strain. Transcriptomic and proteomic assays using RNA sequencing and mass spectrometry, respectively, were conducted on the ΔSSA_0351 mutant to evaluate the functional impact of SPase on biofilm formation. Subsequently, bioinformatics analysis revealed a number of proteins that were differentially regulated in the ΔSSA_0351 mutant, narrowing down the list of SPase substrates involved in biofilm formation to lactate dehydrogenase (SSA_1221) and a short-chain dehydrogenase (SSA_0291). With further experimentation, this list defined the link between SSA_0351-encoded SPase, cell wall biosynthesis and biofilm formation.}, } @article {pmid28868050, year = {2017}, author = {Rollin-Pinheiro, R and de Meirelles, JV and Vila, TVM and Fonseca, BB and Alves, V and Frases, S and Rozental, S and Barreto-Bergter, E}, title = {Biofilm Formation by Pseudallescheria/Scedosporium Species: A Comparative Study.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1568}, pmid = {28868050}, issn = {1664-302X}, abstract = {Pseudallescheria/Scedosporium species are medically important fungi that are present in soil and human impacted areas and capable of causing a wide spectrum of diseases in humans. Although little is known about their pathogenesis, their growth process and infection routes are very similar to those of Aspergillus species, which grow as biofilms in invasive infections. All nine strains tested here displayed the ability to grow as biofilms in vitro and to produce a dense network of interconnected hyphae on both polystyrene and the surfaces of central venous catheters, but with different characteristics. Scedosporium boydii and S. aurantiacum clinical isolates were able to form biofilms faster than the corresponding environmental strains, as evidenced in kinetic assays for S. boydii and CLSM for S. aurantiacum. Biofilms formed by Pseudallescheria/Scedosporium species had significantly higher resistance to the class of antifungal azole than was observed in planktonic cells, indicating a protective role for this structure. In addition, the clinical S. aurantiacum isolate that formed the most robust biofilms was also more virulent in a larvae Galleria mellonella infection model, suggesting that the ability to form biofilms enhances virulence in Pseudallescheria/Scedosporium species.}, } @article {pmid28867635, year = {2017}, author = {Goswami, S and Sarkar, R and Saha, P and Maity, A and Sarkar, T and Das, D and Chakraborty, PD and Bandyopadhyay, S and Ghosh, CK and Karmakar, S and Sen, T}, title = {Effect of human placental extract in the management of biofilm mediated drug resistance - A focus on wound management.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {307-315}, doi = {10.1016/j.micpath.2017.08.041}, pmid = {28867635}, issn = {1096-1208}, mesh = {Biofilms/*drug effects ; Humans ; Placental Extracts/*pharmacology ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development/physiology ; Quorum Sensing/drug effects ; Staphylococcus aureus/*drug effects/genetics/growth & development/physiology ; Wound Infection/*microbiology ; }, abstract = {Management of infectious wounds, particularly chronic wounds and burn injuries, is a matter of global concern. Worldwide estimates reveal that, billions of dollars are being spent annually for the management of such chronic ailments. Evidently, bacterial biofilms pose a greater problem in the effective management of infection in chronic wounds, since most of the currently available antibiotics are unable to act on the microorganisms residing inside the protected environment of the biofilms. Accordingly, in the present study, we have attempted to evaluate the anti-biofilm properties of human placental extract (PLX) and also other virulence factors that are mediated via the quorum sensing (QS) signalling system. PLX is well known for its anti inflammatory action and it has been shown earlier some anti microbial and enzymatic activity also. PLX was found to produce significant inhibition of biofilm formation and also decreased the levels of pyoverdin and pyocyanin. The microscopic analysis (both light microscopy and atomic force microscopy) of biofilms was also used for substantiating the findings from spectrophotometric (crystal violet estimation) and fluorescence analysis (resazurin uptake). PLX pre-treatment decreased the hydrophobicity of gram-positive and gram negative cells, indicating the effect of placental extract on adherence property of planktonic cell, serving as an indicator for its antibiofilm effect on microorganisms. The reduced extracellular DNA (eDNA) content in biofilm matrix following treatment with PLX also indicates the effectiveness of placenta extract on bacterial adherence, which in turn serves as evidence substantiating the antibiofilm effects of the PLX. Furthermore, PLX was also found to be significantly effective in the in vitro wound biofilm model. Thus the present study, the first of its kind with PLX, establishes the therapeutic benefit of the same particularly in infected wounds, opening up newer avenue for further exploration.}, } @article {pmid28867634, year = {2017}, author = {Malaikozhundan, B and Vijayakumar, S and Vaseeharan, B and Jenifer, AA and Chitra, P and Prabhu, NM and Kannapiran, E}, title = {Two potential uses for silver nanoparticles coated with Solanum nigrum unripe fruit extract: Biofilm inhibition and photodegradation of dye effluent.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {316-324}, doi = {10.1016/j.micpath.2017.08.039}, pmid = {28867634}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacteria/drug effects ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Coloring Agents/*chemistry ; Fruit/chemistry ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/chemistry/*pharmacology ; Silver/chemistry/*pharmacology ; Solanum nigrum/*chemistry ; }, abstract = {Silver nanoparticle was green synthesized involving the unripe fruit extracts of Solanum nigrum (Sn-AgNPs). The synthesized Sn-AgNPs was bio-physically characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). UV-Vis recorded the absorbance spectra at 443 nm. XRD analysis clearly demonstrated the crystalline nature of Sn-AgNPs with Bragg's reflection peaks at 111, 200, 220 and 311 lattice planes. The FTIR spectrum of Sn-AgNPs showed strong bands at 3432, 1555, 1455, 862 and 406 cm[-1] which corresponds at O-H, C-H, C-C, C-OH and C-N groups respectively. TEM exhibited the spherical shape of Sn-AgNPs with particle size between 20 and 30 nm. The antibacterial effects of Sn-AgNPs were tested on clinically important biofilm forming Gram positive (Bacillus pumulis and Enterococcus faecalis) and Gram negative (Proteus vulgaris and Vibrio parahaemolyticus) bacteria. The greater inhibition of B. pumulis and E. faecalis was observed at 100 μg mL[-1] of Sn-AgNPs compared to P. vulgaris and V. parahaemolyticus. The biofilm inhibition potential of Sn-AgNPs was greater against Gram positive bacteria than that of Gram negative bacteria. Furthermore, Sn-AgNPs effectively degraded the industrial effluent methyl orange dye by photocatalysis. It is concluded that Sn-AgNPs could be used as an effective therapeutics against the biofilm of clinically important bacteria. The green synthesized Sn-AgNPs can be employed to degrade dye effluents and prevent environmental pollution as well.}, } @article {pmid28867627, year = {2017}, author = {Amrutha, B and Sundar, K and Shetty, PH}, title = {Effect of organic acids on biofilm formation and quorum signaling of pathogens from fresh fruits and vegetables.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {156-162}, doi = {10.1016/j.micpath.2017.08.042}, pmid = {28867627}, issn = {1096-1208}, mesh = {Acetic Acid/pharmacology ; Acids/*pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Citric Acid/pharmacology ; Escherichia coli/drug effects ; *Food Microbiology ; Food Preservation/*methods ; Food Preservatives ; Fruit/*microbiology ; Lactic Acid/pharmacology ; Microbial Sensitivity Tests ; Salmonella/drug effects ; Vegetables/*microbiology ; }, abstract = {Organic acids are known to be used as food preservatives due to their antimicrobial potential. This study evaluated the ability of three organic acids, namely, acetic acid, citric acid and lactic acid to manage E. coli and Salmonella sp. from fresh fruits and vegetables. Effect of these organic acids on biofilm forming ability and anti-quorum potential was also investigated. The effect of organic acids on inactivation of E. coli and Salmonella sp. on the surface of a selected vegetable (cucumber) was determined. The minimum inhibitory concentration of the organic acids were found to be 1.5, 2 and 0.2% in E. coli while it was observed to be 1, 1.5 and 1% in Salmonella sp. for acetic, citric and lactic acids respectively. Maximum inhibition of biofilm formation was recorded at 39.13% with lactic acid in E. coli and a minimum of 22.53% with citric acid in Salmonella sp. EPS production was affected in E. coli with lactic acid showing reduction by 13.42% while citric acid and acetic acid exhibited only 6.25% and 10.89% respectively. Swimming and swarming patterns in E. coli was notably affected by both acetic and lactic acids. Lactic and acetic acids showed higher anti-quorum sensing (QS) potential when compared to citric acid. 2% lactic acid showed a maximum inhibition of violacein production by 37.7%. Organic acids can therefore be used as potential quorum quenching agents in food industry. 2% lactic acid treatment on cucumber demonstrated that it was effective in inactivating E. coli and Salmonella sp. There was 1 log reduction in microbial count over a period of 6 days after the lactic acid treatment. Thus, organic acids can act as effective potential sanitizers in reducing the microbial load associated with fresh fruits and vegetables.}, } @article {pmid28866443, year = {2017}, author = {Zhou, L and Li, T and An, J and Liao, C and Li, N and Wang, X}, title = {Subminimal inhibitory concentration (sub-MIC) of antibiotic induces electroactive biofilm formation in bioelectrochemical systems.}, journal = {Water research}, volume = {125}, number = {}, pages = {280-287}, doi = {10.1016/j.watres.2017.08.059}, pmid = {28866443}, issn = {1879-2448}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Electron Transport ; Geobacter/*drug effects/physiology ; Microbial Sensitivity Tests ; }, abstract = {Electroactive biofilms (EABs) generated from mixed inocula are attractive due to their unique direct extracellular electron transfer abilities and potential use in water pollution control. In this study, for the first time, we identified a chemical that can be used for EAB regulation (both inhibition and promotion). We confirmed that tobramycin, an antibiotic previously demonstrated to inhibit the activity of EABs, is an agonist of EAB formation at subminimal inhibitory concentrations (sub-MICs). Compared to the control, at tobramycin concentrations of 0.05 (1/80 MIC) and 0.1 mg/L (1/40 MIC), the time required to reach 3 A/m[2] was shorter, and the limiting current densities increased by 17%. The enhanced EAB activity was primarily attributed to the 50% increase in biomass density from 289 ± 21 to 434 ± 12 μg protein/cm[2] and the increased biofilm thickness from 28 ± 1 to 37 ± 0.5 μm. Geobacter species in the microbial communities were selectively increased from 76% to 82%, and their abundance was estimated to increase by 1.63-fold. The accelerated growth was further confirmed using the model strain G. sulfurreducens PCA. Transcriptomic analysis revealed that 0.05 mg/L of tobramycin led to a significant upregulation of genes related to cytochromes and the type IV pilus, suggesting a possible mechanism for the observed current enhancement. These findings extend our knowledge of the regulation of EAB formation by antibiotics and the selective enrichment of Geobacter from a mixed culture, with broader implications on the potential impact of trace antibiotics on the dissimilatory metal reduction process in water environment.}, } @article {pmid28866198, year = {2017}, author = {Pihl, M and Bruzell, E and Andersson, M}, title = {Bacterial biofilm elimination using gold nanorod localised surface plasmon resonance generated heat.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {80}, number = {}, pages = {54-58}, doi = {10.1016/j.msec.2017.05.067}, pmid = {28866198}, issn = {1873-0191}, mesh = {*Biofilms ; Gold ; Hot Temperature ; Nanotubes ; Surface Plasmon Resonance ; }, abstract = {Antimicrobial resistance is an increasing global health concern and the world is facing a major challenge to develop novel ways of replacing antibiotics. Gold nanorods exhibit localised surface plasmon resonance upon optical irradiation. During relaxation, absorbed energy is dissipated as heat, which has been utilized to kill bacteria. In this study, 10×45nm gold nanorods were attached to glass surfaces using silanisation. Then biofilms were cultured on the surfaces and studied using microscopy. On average, 71% of the early biofilm bacteria were eliminated after 5min of near infrared radiation (LED emission peak at 850nm) of the gold nanorod coated surfaces, showing the potential of this novel antibiofilm technique. Most notably, the best individual result showed 97% biofilm elimination. This study demonstrates that nanoplasmonic generated heat offers a novel way of eliminating bacterial biofilms. In future applications, this method may be used to eliminate bacterial contamination during implant surgery.}, } @article {pmid28865065, year = {2018}, author = {Staun Larsen, L and Baelum, V and Tenuta, LMA and Richards, A and Nyvad, B}, title = {Fluoride in saliva and dental biofilm after 1500 and 5000 ppm fluoride exposure.}, journal = {Clinical oral investigations}, volume = {22}, number = {3}, pages = {1123-1129}, pmid = {28865065}, issn = {1436-3771}, mesh = {Adult ; Biofilms/*drug effects ; Cross-Over Studies ; Double-Blind Method ; Female ; Fluorides/*administration & dosage/*analysis ; Humans ; Mouthwashes/*chemistry ; Saliva/*chemistry ; Toothpastes/chemistry ; }, abstract = {OBJECTIVES: The aim of this randomized, double-blind, crossover study was to measure fluoride in saliva and 7-day-old biofilm fluid and biofilm solids after rinsing three times per day for 3 weeks with 0, 1500, or 5000 ppm fluoride (NaF).

MATERIALS AND METHODS: Following the 3-week wash-in/wash-out period, including 1 week of biofilm accumulation, saliva and biofilm samples were collected from 12 participants immediately before (background fluoride), and 10, 30, and 60 min after a single rinse. Biofilm samples were separated into fluid and solids, and samples were analyzed using a fluoride electrode (microanalysis).

RESULTS: The background fluoride concentration was statistically significantly higher in the 5000 compared to the 1500 ppm F rinse group in all three compartments (22.3 and 8.1 μM in saliva, 126.8 and 58.5 μM in biofilm fluid, and 10,940 and 4837 μmol/kg in biofilm solids). The 1-h fluoride accumulation for the 5000 ppm F rinse was higher than for the 1500 ppm F rinse in all three compartments, although not statistically significant for saliva and biofilm solids.

CONCLUSION: Regular exposure to 5000 ppm fluoride elevates background fluoride concentrations in saliva, biofilm fluid, and biofilm solids compared to 1500 ppm fluoride. Increasing the fluoride concentration almost 3.5 times (from 1500 to 5000 ppm) only elevates the background fluoride concentrations in saliva, biofilm fluid, and biofilm solids twofold.

CLINICAL RELEVANCE: Even though fluoride toothpaste may be diluted by saliva, the results of the present study indicate that use of 5000 ppm fluoride toothpaste might lead to improved caries control.}, } @article {pmid28864061, year = {2017}, author = {Brignardello-Petersen, R}, title = {Chlorhexidine with and without alcohol is effective in preventing biofilm formation in highly compliant patients, but chlorhexidine without alcohol has fewer adverse effects and better palatability.}, journal = {Journal of the American Dental Association (1939)}, volume = {148}, number = {11}, pages = {e162}, doi = {10.1016/j.adaj.2017.07.027}, pmid = {28864061}, issn = {1943-4723}, mesh = {*Anti-Infective Agents, Local ; Biofilms ; *Chlorhexidine ; Humans ; Taste ; }, } @article {pmid28863128, year = {2017}, author = {Wei, L and Wu, R and Wang, C and Wu, Z}, title = {Effects of ε-Polylysine on Pseudomonas Aeruginosa and Aspergillus Fumigatus Biofilm In Vitro.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {23}, number = {}, pages = {4225-4229}, pmid = {28863128}, issn = {1643-3750}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents ; Aspergillus fumigatus/*drug effects ; Biofilms/drug effects ; Microbial Sensitivity Tests ; Polylysine/metabolism/*therapeutic use ; Pseudomonas aeruginosa/*drug effects/metabolism ; }, abstract = {BACKGROUND The antimicrobial mechanisms of ε-polylysine (EPL) against Pseudomonas aeruginosa and Aspergillus fumigatus biofilm were investigated. MATERIAL AND METHODS We assessed the changes in electric conductivity of broth and total sugar concentration, as well as changes in phosphorous metabolism and protein expression, of the 2 organisms before and after treatment with EPL. RESULTS The experimental results showed that EPL has antimicrobial activity against Pseudomonas aeruginosa and Aspergillus fumigatus, but the activity was much stronger for the former. After treatment with EPL, the electric conductivity and total sugar concentration of microbial broth increased, suggesting that EPL damages the cell membrane structure, which increases permeability of the cell membrane and release of cell components. CONCLUSIONS The consumption of phosphorous decreased in the EPL-treated organisms, which seriously affected the synthesis of important cell components such as nucleic acid and phospholipid, as well as energy metabolism.}, } @article {pmid28861520, year = {2017}, author = {Ledder, RG and Mistry, H and Sreenivasan, PK and Humphreys, G and McBain, AJ}, title = {Arginine Exposure Decreases Acidogenesis in Long-Term Oral Biofilm Microcosms.}, journal = {mSphere}, volume = {2}, number = {4}, pages = {}, pmid = {28861520}, issn = {2379-5042}, abstract = {Arginine is an important pH-elevating agent in the oral cavity. It has been incorporated in oral hygiene formulations to mitigate sensitivity and to prevent caries. In this investigation, the effects of sustained arginine dosing of dental plaque microcosms on bacteriological composition and pH were evaluated under controlled conditions. Plaque microcosms were established in constant-depth film fermentors (CDFFs) using salivary inocula and fed continuously with artificial saliva. To simulate resting and cariogenic states, the CDFFs were supplemented with sterile water or 5% sucrose, respectively. Plaques were then dosed twice daily with a dentifrice with 1.5% arginine arginine added (DA) or without arginine (DN). This regimen continued for over 3 weeks, after which fermentors were maintained without dosing. Microcosms were analyzed by differential viable counting, with a pH microelectrode, and by eubacterial DNA profiling. Sucrose dosing was associated with significantly (P < 0.001) decreased pH, significantly (P < 0.05) increased counts of total aerobes, Gram-negative anaerobes, aciduric species, acidogenic species, arginine utilizing species, bifidobacteria, lactobacilli and streptococci, and significant (P < 0.05) changes in DNA profiles. Plaques dosed with DA had a significantly (P < 0.001) higher pH than those dosed with DN, with or without sucrose supplementation. Dosing with DA but not DN significantly (P < 0.05) decreased counts of all functional bacterial groups apart from the total anaerobes in cariogenic plaques, and in resting plaques, dosing with DA significantly (P < 0.05) decreased counts of streptococci, lactobacilli, bifidobacteria, and acidogenic bacteria. In summary, sustained exposure of oral microcosms to arginine in formulation significantly increased plaque pH and significantly reduced the viability of cariogenic bacterial species. IMPORTANCE Arginine is used in dental health formulations to help prevent dental cavities. This study assessed the effects of the long-term dosing of laboratory dental plaques with an arginine dentifrice. Data indicate that the addition of arginine dentifrice during sucrose challenge significantly increased plaque pH, thus potentially mitigating cariogenesis. Counts of several functional groups of bacteria associated with tooth decay were significantly decreased in the laboratory plaques during exposure to the arginine dentifrice.}, } @article {pmid28861286, year = {2017}, author = {Song, WS and Lee, JK and Park, SH and Um, HS and Lee, SY and Chang, BS}, title = {Comparison of periodontitis-associated oral biofilm formation under dynamic and static conditions.}, journal = {Journal of periodontal & implant science}, volume = {47}, number = {4}, pages = {219-230}, pmid = {28861286}, issn = {2093-2278}, abstract = {PURPOSE: The purpose of this study was to compare the characteristics of single- and dual-species in vitro oral biofilms made by static and dynamic methods.

METHODS: Hydroxyapatite (HA) disks, 12.7 mm in diameter and 3 mm thick, were coated with processed saliva for 4 hours. The disks were divided into a static method group and a dynamic method group. The disks treated with a static method were cultured in 12-well plates, and the disks in the dynamic method group were cultured in a Center for Disease Control and Prevention (CDC) biofilm reactor for 72 hours. In the single- and dual-species biofilms, Fusobacterium nucleatum and Porphyromonas gingivalis were used, and the amount of adhering bacteria, proportions of species, and bacterial reduction of chlorhexidine were examined. Bacterial adhesion was examined with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).

RESULTS: Compared with the biofilms made using the static method, the biofilms made using the dynamic method had significantly lower amounts of adhering and looser bacterial accumulation in SEM and CLSM images. The proportion of P. gingivalis was higher in the dynamic method group than in the static method group; however, the difference was not statistically significant. Furthermore, the biofilm thickness and bacterial reduction by chlorhexidine showed no significant differences between the 2 methods.

CONCLUSIONS: When used to reproduce periodontal biofilms composed of F. nucleatum and P. gingivalis, the dynamic method (CDC biofilm reactor) formed looser biofilms containing fewer bacteria than the well plate. However, this difference did not influence the thickness of the biofilms or the activity of chlorhexidine. Therefore, both methods are useful for mimicking periodontitis-associated oral biofilms.}, } @article {pmid28861053, year = {2017}, author = {Jia, R and Li, Y and Al-Mahamedh, HH and Gu, T}, title = {Enhanced Biocide Treatments with D-amino Acid Mixtures against a Biofilm Consortium from a Water Cooling Tower.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1538}, pmid = {28861053}, issn = {1664-302X}, abstract = {Different species of microbes form mixed-culture biofilms in cooling water systems. They cause microbiologically influenced corrosion (MIC) and biofouling, leading to increased operational and maintenance costs. In this work, two D-amino acid mixtures were found to enhance two non-oxidizing biocides [tetrakis hydroxymethyl phosphonium sulfate (THPS) and NALCO 7330 (isothiazoline derivatives)] and one oxidizing biocide [bleach (NaClO)] against a biofilm consortium from a water cooling tower in lab tests. Fifty ppm (w/w) of an equimass mixture of D-methionine, D-leucine, D-tyrosine, D-tryptophan, D-serine, D-threonine, D-phenylalanine, and D-valine (D8) enhanced 15 ppm THPS and 15 ppm NALCO 7330 with similar efficacies achieved by the 30 ppm THPS alone treatment and the 30 ppm NALCO 7330 alone treatment, respectively in the single-batch 3-h biofilm removal test. A sequential treatment method was used to enhance bleach because D-amino acids react with bleach. After a 4-h biofilm removal test, the sequential treatment of 5 ppm bleach followed by 50 ppm D8 achieved extra 1-log reduction in sessile cell counts of acid producing bacteria, sulfate reducing bacteria, and general heterotrophic bacteria compared with the 5 ppm bleach alone treatment. The 10 ppm bleach alone treatment showed a similar efficacy with the sequential treatment of 5 ppm bleach followed by 50 ppm D8. The efficacy of D8 was found better than that of D4 (an equimass mixture of D-methionine, D-leucine, D-tyrosine, and D-tryptophan) in the enhancement of the three individual biocides against the biofilm consortium.}, } @article {pmid28860065, year = {2018}, author = {Muslim, SN and Kadmy, IMSA and Ali, ANM and Salman, BK and Ahmad, M and Khazaal, SS and Hussein, NH and Muslim, SN}, title = {Chitosan extracted from Aspergillus flavus shows synergistic effect, eases quorum sensing mediated virulence factors and biofilm against nosocomial pathogen Pseudomonas aeruginosa.}, journal = {International journal of biological macromolecules}, volume = {107}, number = {Pt A}, pages = {52-58}, doi = {10.1016/j.ijbiomac.2017.08.146}, pmid = {28860065}, issn = {1879-0003}, mesh = {Aspergillus flavus/*chemistry ; Bacterial Proteins/genetics ; Biofilms/drug effects ; Chitosan/chemistry/isolation & purification/*pharmacology ; Cross Infection/*drug therapy/genetics/microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/genetics/pathogenicity ; Quorum Sensing/drug effects ; Trans-Activators/genetics ; }, abstract = {The biological methods for extraction of chitosan were used as alternative procedures for chemical methods In biological methods, the chitosan was extracted from A. flavus by using of Lactobacillus paracasei for demineralization and Bacillus subtilis for deproteinization. The yield of extracted chitosan reached to 53.8%, pH was 7.8 and complete solubility in 1% acitic acid. Purified chitosan had the ability to reduce the biofilm forming capacity of P. aeruginosa clearly visible in light microscopic staining and scanning electron microscopy. The QS dependent phenotype and QS regulated gene expression was significantly reduced in the influence of chitosan. A significant decrease in biofilm formation was seen in the presence of chitosan. The chitosan treatment showed a decrease in the expression of lasR and rhlR genes. Same time production of pyocyanin and proteases was also inhibited in dose dependent manner. Chitosan led to increasing antimicrobial activity of antibiotics and had synergism effect, thus chitosan may be a useful adjuvant agent for the treatment of many bacterial infections in combination with antibiotics.}, } @article {pmid28859444, year = {2017}, author = {Belfield, K and Bayston, R and Hajduk, N and Levell, G and Birchall, JP and Daniel, M}, title = {Evaluation of combinations of putative anti-biofilm agents and antibiotics to eradicate biofilms of Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {9}, pages = {2531-2538}, doi = {10.1093/jac/dkx192}, pmid = {28859444}, issn = {1460-2091}, support = {F24/ACT_/Action on Hearing Loss/United Kingdom ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Clindamycin/pharmacology ; Deoxyribonuclease I/pharmacology ; Gentamicins/pharmacology ; Humans ; Hydrogen Peroxide/pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/physiology ; Soaps/chemistry/pharmacology ; Staphylococcus aureus/*drug effects/physiology ; Vancomycin/pharmacology ; }, abstract = {OBJECTIVES: To evaluate potential anti-biofilm agents for their ability to enhance the activity of antibiotics for local treatment of localized biofilm infections.

METHODS: Staphylococcus aureus and Pseudomonas aeruginosa in vitro biofilm models were developed. The putative antibiotic enhancers N-acetylcysteine, acetylsalicylic acid, sodium salicylate, recombinant human deoxyribonuclease I, dispersin B, hydrogen peroxide and Johnson's Baby Shampoo (JBS) were tested for their anti-biofilm activity alone and their ability to enhance the activity of antibiotics for 7 or 14 days, against 5 day old biofilms. The antibiotic enhancers were paired with rifampicin and clindamycin against S. aureus and gentamicin and ciprofloxacin against P. aeruginosa. Isolates from biofilms that were not eradicated were tested for antibiotic resistance.

RESULTS: Antibiotic levels 10× MIC and 100× MIC significantly reduced biofilm, but did not consistently eradicate it. Antibiotics at 100× MIC with 10% JBS for 14 days was the only treatment to eradicate both staphylococcal and pseudomonal biofilms. Recombinant human deoxyribonuclease I significantly reduced staphylococcal biofilm. Emergence of resistance of surviving isolates was minimal and was often associated with the small colony variant phenotype.

CONCLUSIONS: JBS enhanced the activity of antibiotics and several other promising anti-biofilm agents were identified. Antibiotics with 10% JBS eradicated biofilms produced by both organisms. Such combinations might be useful in local treatment of localized biofilm infections.}, } @article {pmid28859308, year = {2017}, author = {Leite, B and Werle, CH and Carmo, CPD and Nóbrega, DB and Milanez, GP and Culler, HF and Sircili, MP and Alvarez-Martinez, CE and Brocchi, M}, title = {Integration host factor is important for biofilm formation by Salmonella enterica Enteritidis.}, journal = {Pathogens and disease}, volume = {75}, number = {6}, pages = {}, doi = {10.1093/femspd/ftx074}, pmid = {28859308}, issn = {2049-632X}, mesh = {Biofilms/*growth & development ; Cellulose/biosynthesis ; Fimbriae, Bacterial/*genetics/metabolism ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Genetic Fitness ; Integration Host Factors/deficiency/*genetics ; Plankton/*genetics/growth & development/metabolism ; Polysaccharides, Bacterial/biosynthesis/deficiency ; Protein Subunits/deficiency/genetics ; Salmonella enteritidis/*genetics/growth & development/metabolism/pathogenicity ; }, abstract = {Salmonella enterica Enteritidis forms biofilms and survives in agricultural environments, infecting poultry and eggs. Bacteria in biofilms are difficult to eradicate compared to planktonic cells, causing serious problems in industry and public health. In this study, we evaluated the role of ihfA and ihfB in biofilm formation by S. enterica Enteritidis by employing different microbiology techniques. Our data indicate that ihf mutant strains are impaired in biofilm formation, showing a reduction in matrix formation and a decrease in viability and metabolic activity. Phenotypic analysis also showed that deletion of ihf causes a deficiency in curli fimbriae expression, cellulose production and pellicle formation. These results show that integration host factor has an important regulatory role in biofilm formation by S. enterica Enteritidis.}, } @article {pmid28859149, year = {2017}, author = {Seng, R and Kitti, T and Thummeepak, R and Kongthai, P and Leungtongkam, U and Wannalerdsakun, S and Sitthisak, S}, title = {Biofilm formation of methicillin-resistant coagulase negative staphylococci (MR-CoNS) isolated from community and hospital environments.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0184172}, pmid = {28859149}, issn = {1932-6203}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Coagulase/genetics ; Cross Infection/*genetics/microbiology ; Humans ; Methicillin Resistance/*genetics ; Oxacillin/administration & dosage ; Penicillin-Binding Proteins/genetics ; Staphylococcal Infections/*genetics/microbiology ; Staphylococcus epidermidis/genetics/growth & development ; Staphylococcus haemolyticus/genetics/growth & development ; Staphylococcus hominis/genetics/growth & development ; }, abstract = {Methicillin-resistant coagulase negative staphylococci (MR-CoNS) are the major cause of infectious diseases because of their potential ability to form biofilm and colonize the community or hospital environments. This study was designed to investigate the biofilm producing ability, and the presence of mecA, icaAD, bap and fnbA genes in MR-CoNS isolates. The MR-CoNS used in this study were isolated from various samples of community environment and five wards of hospital environments, using mannitol salt agar (MSA) supplemented with 4 μg/ml of oxacillin. The specie level of Staphylococcus haemolyticus, Staphylococcus epidermidis, Staphylococcus hominis and Staphylococcus warneri was identified by specific primers of groESL (S. haemolyticus), rdr (S. epidermidis) and nuc (S. hominis and S. warneri). The remainder isolates were identified by tuf gene sequencing. Biofilm production was determined using Congo red agar (CRA) and Microtiter plate (MTP) assay. The mecA and biofilm associated genes (icaAD, fnbA and bap) were detected using PCR method. From the 558 samples from community and hospital environments, 292 MR-CoNS were isolated (41 from community environments, and 251 from hospital environments). S. haemolyticus (41.1%) and S. epidermidis (30.1%) were the predominant species in this study. Biofilm production was detected in 265 (90.7%) isolates by CRA, and 260 (88.6%) isolates were detected by MTP assay. The staphylococci isolates derived from hospital environments were more associated with biofilm production than the community-derived isolates. Overall, the icaAD and bap genes were detected in 74 (29.5%) and 14 (5.6%) of all isolates from hospital environments. When tested by MTP, the icaAD gene from hospital environment isolates was associated with biofilm biomass. No association was found between bap gene and biofilm formation. The MR-CoNS isolates obtained from community environments did not harbor the icaAD and bap genes. Conversely, fnbA gene presented in MR-CoNS isolated from both community and hospital environments. The high prevalence of biofilm producing MR-CoNS strains demonstrated in this study indicates the persisting ability in environments, and is useful in developing prevention strategies countering the spread of MR-CoNS.}, } @article {pmid28858860, year = {2017}, author = {Maske, TT and Kuper, NK and Cenci, MS and Huysmans, MDNJM}, title = {Minimal Gap Size and Dentin Wall Lesion Development Next to Resin Composite in a Microcosm Biofilm Model.}, journal = {Caries research}, volume = {51}, number = {5}, pages = {475-481}, doi = {10.1159/000478536}, pmid = {28858860}, issn = {1421-976X}, mesh = {Acid Etching, Dental ; Acrylic Resins/*pharmacology ; Animals ; *Biofilms ; Cattle ; Composite Resins/*pharmacology ; Dental Caries/diagnostic imaging/*pathology ; *Dental Restoration, Permanent ; Dentin/diagnostic imaging/*pathology ; Dentin-Bonding Agents/*pharmacology ; Humans ; In Vitro Techniques ; Materials Testing ; Microradiography ; Polyurethanes/*pharmacology ; Saliva/*microbiology ; Surface Properties ; }, abstract = {This in vitro study investigated the development of dentin wall lesions next to resin composite containing very small gap sizes using an in vitro biofilm model, and evaluated whether a relevant threshold for the gap size could be established. Microcosm biofilms were grown for 14 days within small interfacial gaps between dentin-resin composite discs under intermittent cariogenic challenge. The factor under study was gap size: samples were either restored with composite resin without adhesive procedure (no intentional gap; no bonding [NB] group) or with intentional gaps of 30, 60, or 90 µm, or with complete adhesive procedure (no gap; bonding [B] group). Secondary caries wall lesion progression was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography at 3 locations: outer surface lesion and wall lesions at 200 and 500 µm distance from gap entrance. Results from linear regression analysis showed that the presence of an intentional gap (30, 60, and 90 µm) affected the secondary caries progression at 200 µm from the gap entrance (p ≤ 0.013). The NB group did not show significant wall lesion development (ML and LD, p ≥ 0.529). At 500 µm distance almost no wall caries development was observed. In conclusion, dentin wall lesions developed in minimal gap sizes, and the threshold for secondary wall lesion development was a gap of around 30 µm in this microcosm biofilm model.}, } @article {pmid28858750, year = {2018}, author = {Wang, J and Ding, L and Li, K and Huang, H and Hu, H and Geng, J and Xu, K and Ren, H}, title = {Estimation of spatial distribution of quorum sensing signaling in sequencing batch biofilm reactor (SBBR) biofilms.}, journal = {The Science of the total environment}, volume = {612}, number = {}, pages = {405-414}, doi = {10.1016/j.scitotenv.2017.07.277}, pmid = {28858750}, issn = {1879-1026}, mesh = {Acyl-Butyrolactones/analysis ; Bacteria ; *Biofilms ; Bioreactors/*microbiology ; Homoserine/analogs & derivatives/analysis ; Lactones/analysis ; *Quorum Sensing ; Spatial Analysis ; Wastewater ; }, abstract = {Quorum sensing (QS) signaling, plays a significant role in regulating formation of biofilms in the nature; however, little information about the occurrence and distribution of quorum sensing molecular in the biofilm of carriers has been reported. In this study, distribution of QS signaling molecules (the acylated homoserine lactones-AHLs, and AI-2), extracellular polymeric substances (EPS) and the mechanical properties in sequencing batch biofilm reactor (SBBR) biofilms have been investigated. Using increased centrifugal force, the biofilms were detached into different fractions. The AHLs ranged from 5.2ng/g to 98.3ng/g in different fractions of biofilms, and N-decanoyl-dl-homoserine lactone (C10-HSL) and N-dodecanoyl-dl-homoserine lactone (C12-HSL) in the biofilms obtained at various centrifugal forces displayed significant differences (p<0.01). Interspecies communication signal autoinducer-2(AI-2) in the biofilms ranged from 79.2ng/g to 98.3ng/g. Soluble EPS and loosely bound EPS content in the different fractions of biofilms displayed significant positive relationship with the distribution of C12-HSL (r=0.86, p<0.05). Furthermore, 49.62% of bacteria in the biofilms were positively related with AHLs with 22.76% was significantly positively (p<0.05) related with AHLs. Biofilm adhesion and compliance was the strongest in the tightly-bound biofilm, the weakest in the supernatant/surface biofilm, which was in accordance with the distribution of C12 HSL(r=0.77, p<0.05) and C10-HSL(r=0.75, p<0.05), respectively. This study addressed on better understanding of possible methods for the improvement of wastewater bio-treatment through biofilm application.}, } @article {pmid28858283, year = {2017}, author = {Ippolitov, EV and Nikolaeva, EN and Tsarev, VN}, title = {[Oral biofilm: inductors of congenital immunity signal pathways].}, journal = {Stomatologiia}, volume = {96}, number = {4}, pages = {58-62}, doi = {10.17116/stomat201796458-62}, pmid = {28858283}, issn = {0039-1735}, mesh = {*Biofilms ; Gastrointestinal Microbiome/*immunology ; Humans ; *Immunity, Innate ; Mouth/*immunology/*microbiology ; Signal Transduction ; }, } @article {pmid28858273, year = {2017}, author = {Petrukhina, NB and Zorina, OA and Shikh, EV and Kartysheva, EV}, title = {[Microbiocenosis of subgingival biofilm and intestinal content in chronic periodontal disease in patients with metabolic syndrome].}, journal = {Stomatologiia}, volume = {96}, number = {4}, pages = {11-19}, doi = {10.17116/stomat201796411-19}, pmid = {28858273}, issn = {0039-1735}, mesh = {Bacteria/cytology/genetics/isolation & purification ; *Biofilms ; Chronic Periodontitis/*complications/*microbiology ; DNA, Ribosomal/genetics ; Dysbiosis/microbiology ; Gastrointestinal Contents/*microbiology ; *Gastrointestinal Microbiome ; Gingiva/*microbiology ; Humans ; Metabolic Syndrome/*complications ; Microbial Consortia/genetics ; RNA, Ribosomal, 16S/genetics ; }, abstract = {The aim of the study was to assess correlations of subgingival biofilm and intestinal microbiota in patients with chronic periodontal disease (CPD) and metabolic syndrome (MS). The study included 80 patients divided in 2 groups: 40 healthy individuals with no signs of periodontal disease and 40 patients with CPD and MS. Oral and intestinal microbial consortia compositions were revealed using deep sequencing libraries of 16S rDNA. The study showed than the qualitative composition of the intestinal microbiome in patients with CPD differ significantly from the microbiome of controls. Real-time PCR of subgingival microflora in CPD patients revealed high content of P. gingivalis, T. forsythia and T. denticola, while in intestinal microbiome dominated representatives of Enterobacteriaceae and Eubacteriaceae families with signs of intestinal dysbiosis mostly associated with the decrease of protective species.}, } @article {pmid28858232, year = {2017}, author = {Di Domenico, EG and Cavallo, I and Pontone, M and Toma, L and Ensoli, F}, title = {Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer.}, journal = {International journal of molecular sciences}, volume = {18}, number = {9}, pages = {}, pmid = {28858232}, issn = {1422-0067}, mesh = {Animals ; Biofilms/*growth & development ; *Gallbladder Neoplasms/metabolism/microbiology/pathology/prevention & control ; Humans ; Salmonella typhi/*physiology ; *Typhoid Fever/metabolism/pathology/therapy ; }, abstract = {Salmonella enterica subspecies enterica serovar Typhi is the aetiological agent of typhoid or enteric fever. In a subset of individuals, S. Typhi colonizes the gallbladder causing an asymptomatic chronic infection. Nonetheless, these asymptomatic carriers provide a reservoir for further spreading of the disease. Epidemiological studies performed in regions where S. Typhi is endemic, revealed that the majority of chronically infected carriers also harbour gallstones, which in turn, have been indicated as a primary predisposing factor for the onset of gallbladder cancer (GC). It is now well recognised, that S. Typhi produces a typhoid toxin with a carcinogenic potential, that induces DNA damage and cell cycle alterations in intoxicated cells. In addition, biofilm production by S. Typhi may represent a key factor for the promotion of a persistent infection in the gallbladder, thus sustaining a chronic local inflammatory response and exposing the epithelium to repeated damage caused by carcinogenic toxins. This review aims to highlight the putative connection between the chronic colonization by highly pathogenic strains of S. Typhi capable of combining biofilm and toxin production and the onset of GC. Considering the high risk of GC associated with the asymptomatic carrier status, the rapid identification and profiling of biofilm production by S. Typhi strains would be key for effective therapeutic management and cancer prevention.}, } @article {pmid28857343, year = {2017}, author = {Percival, SL and Mayer, D and Salisbury, AM}, title = {Efficacy of a surfactant-based wound dressing on biofilm control.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {25}, number = {5}, pages = {767-773}, doi = {10.1111/wrr.12581}, pmid = {28857343}, issn = {1524-475X}, mesh = {Anti-Infective Agents/administration & dosage ; *Bandages ; *Biofilms ; Humans ; Surface-Active Agents/*administration & dosage ; Wound Healing/*drug effects ; Wound Infection/*therapy ; }, abstract = {The aim of this study was to evaluate the efficacy of both a nonantimicrobial and antimicrobial (1% silver sulfadiazine-SSD) surfactant-based wound dressing in the control of Pseudomonas aeruginosa, Enterococcus sp, Staphylococcus epidermidis, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) biofilms. Anti-biofilm efficacy was evaluated in numerous adapted American Standards for Testing and Materials (ASTM) standard biofilm models and other bespoke biofilm models. The ASTM standard models employed included the Minimum biofilm eradication concentration (MBEC) biofilm model (ASTM E2799) and the Centers for Disease Control (CDC) biofilm reactor model (ASTM 2871). Such bespoke biofilm models included the filter biofilm model and the chamberslide biofilm model. Results showed complete kill of microorganisms within a biofilm using the antimicrobial surfactant-based wound dressing. Interestingly, the nonantimicrobial surfactant-based dressing could disrupt existing biofilms by causing biofilm detachment. Prior to biofilm detachment, we demonstrated, using confocal laser scanning microscopy (CLSM), the dispersive effect of the nonantimicrobial surfactant-based wound dressing on the biofilm within 10 minutes of treatment. Furthermore, the non-antimicrobial surfactant-based wound dressing caused an increase in microbial flocculation/aggregation, important for microbial concentration. In conclusion, this nonantimicrobial surfactant-based wound dressing leads to the effective detachment and dispersion of in vitro biofilms. The use of surfactant-based wound dressings in a clinical setting may help to disrupt existing biofilm from wound tissue and may increase the action of antimicrobial treatment.}, } @article {pmid28854684, year = {2017}, author = {Li, B and Zhou, X and Zhou, X and Wu, P and Li, M and Feng, M and Peng, X and Ren, B and Cheng, L}, title = {Effects of different substrates/growth media on microbial community of saliva-derived biofilm.}, journal = {FEMS microbiology letters}, volume = {364}, number = {13}, pages = {}, doi = {10.1093/femsle/fnx123}, pmid = {28854684}, issn = {1574-6968}, mesh = {Bacteria/*drug effects/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Culture Media/*pharmacology ; Cysteine/pharmacology ; Dental Plaque/microbiology ; Durapatite/pharmacology ; Glass/chemistry ; Humans ; Linear Models ; Microbial Consortia/*drug effects ; RNA, Ribosomal, 16S ; Saliva/*microbiology ; Saliva, Artificial/pharmacology ; }, abstract = {The aims of this study were to investigate the effects of substrates (glass versus hydroxyapatite [HA]) and growth media (SHI medium versus a modified artificial saliva medium with cysteine) on the microbial community of saliva-derived biofilm in vitro. 16S rRNA gene sequencing technology was used to analyze the microbial community of saliva-derived biofilm cultured for 72 h anaerobically. The metagenomes of biofilms were predicted from the clusters of orthologous groups. No significant difference was found between the saliva-derived biofilms grown on HA and glass in ACE, Chao, Shannon and Simpson indices. The abundances of only a few bacteria on HA were significantly different from those on glass with a low relative abundance (<0.5%). Compared with the biofilms developed in a modified artificial saliva medium with cysteine, biofilms in SHI medium were significantly higher (P < 0.05) in diversity. Linear discriminant analysis coupled with effect size measurement showed that some obligate anaerobic genera (Lactobacillus, Veillonella, Porphyromonas and Leptotrichia) were more abundant in SHI medium biofilms. The biofilms grown in different media were also significantly different in predicted gene categories. In conclusion, the growth media, not the substrates, have significant effects on the microbial community of saliva-derived biofilm in vitro.}, } @article {pmid28851144, year = {2018}, author = {Mallick, I and Bhattacharyya, C and Mukherji, S and Dey, D and Sarkar, SC and Mukhopadhyay, UK and Ghosh, A}, title = {Effective rhizoinoculation and biofilm formation by arsenic immobilizing halophilic plant growth promoting bacteria (PGPB) isolated from mangrove rhizosphere: A step towards arsenic rhizoremediation.}, journal = {The Science of the total environment}, volume = {610-611}, number = {}, pages = {1239-1250}, doi = {10.1016/j.scitotenv.2017.07.234}, pmid = {28851144}, issn = {1879-1026}, mesh = {Arsenic/*metabolism ; Bacteria/*growth & development/isolation & purification ; *Biodegradation, Environmental ; Biofilms/*growth & development ; India ; Microbial Consortia ; *Rhizosphere ; Salt-Tolerant Plants ; Water Pollutants, Chemical/*metabolism ; *Wetlands ; }, abstract = {Arsenic (As) uptake by plants is largely influenced by the presence of microbial consortia and their interactions with As. In the coastal region of Bengal deltaic plain of Eastern India, the As-contaminated groundwater is frequently used for irrigation purposes resulting in an elevated level of soil As in agricultural lands. The health hazards associated with As necessitates development of cost-effective remediation strategies to reclaim contaminated agricultural lands. Among the available technologies developed in recent times, bioremediation using bacteria has been found to be the most propitious. In this study, two As-resistant halophilic bacterial strains Kocuria flava AB402 and Bacillus vietnamensis AB403 were isolated, identified and characterized from mangrove rhizosphere of Sundarban. The isolates, AB402 and AB403, could tolerate 35mM and 20mM of arsenite, respectively. The effect of As on the exopolysaccharide (EPS) synthesis, biofilm formation, and root association was evaluated for both the bacterial strains. Arsenic adsorption on the cell surfaces and intracellular accumulation in both the bacterial strains were promising under culture conditions. Moreover, both the strains when used as inoculum, not only promoted the growth of rice seedlings but also decreased As uptake and accumulation in plants.}, } @article {pmid28850838, year = {2018}, author = {Dalahmeh, S and Ahrens, L and Gros, M and Wiberg, K and Pell, M}, title = {Potential of biochar filters for onsite sewage treatment: Adsorption and biological degradation of pharmaceuticals in laboratory filters with active, inactive and no biofilm.}, journal = {The Science of the total environment}, volume = {612}, number = {}, pages = {192-201}, doi = {10.1016/j.scitotenv.2017.08.178}, pmid = {28850838}, issn = {1879-1026}, mesh = {Adsorption ; Biodegradation, Environmental ; *Biofilms ; Charcoal/*chemistry ; Pharmaceutical Preparations/*isolation & purification ; *Sewage ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*isolation & purification ; }, abstract = {This study investigated the potential of biochar filters as a replacement or complement for sand filters for removal of pharmaceutically active compounds (PhACs) from wastewater in onsite sewage facilities (OSSF). Specifically, the study investigated the effects of biodegradation, adsorption and a combination of these processes on removal of four model PhACs from wastewater in biochar filters operated under hydraulic loading conditions mimicking those found in onsite infiltration beds. Concentrations and removal of the four PhACs (i.e. carbamazepine, metoprolol, ranitidine and caffeine) were investigated over 22weeks in four treatments: biochar (BC) with active or inactive biofilm (BC-active-biofilm, BC-inactive-biofilm), biochar without biofilm (BC-no-biofilm) and sand with active biofilm (Sand-active-biofilm). The adsorption of carbamazepine was high in BC-no-biofilm (99% removal after 22weeks), while biodegradation was very low in Sand-active-biofilm (7% removal after 22weeks). Removal of carbamazepine in BC-active-biofilm was high and stable over the 22weeks (>98%), showing a significant role of biofilm in filter biogeneration. However, carbamazepine removal declined over time in BC-inactive-biofilm, from 99% in week 13 to 73% in week 22. Metoprolol was poorly degraded in Sand-active-biofilm (37% after 22weeks), while adsorption seemed to be the major pathway for removal of metoprolol in biochar. Ranitidine and caffeine were efficiently removed by either adsorption (97% and 98%, respectively, after 22weeks) or biodegradation (99% and >99%, respectively, after 22weeks). In conclusion, biochar is a promising filter medium for OSSF, especially for persistent PhACs such as carbamazepine and metoprolol.}, } @article {pmid28848715, year = {2017}, author = {Ren, GX and Guo, XP and Sun, YC}, title = {HmsC Controls Yersinia pestis Biofilm Formation in Response to Redox Environment.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {355}, pmid = {28848715}, issn = {2235-2988}, mesh = {Bacterial Proteins/genetics/*physiology ; Biofilms/*growth & development ; Copper Sulfate/metabolism ; Cyclic GMP/analogs & derivatives/metabolism ; Oxidation-Reduction ; Periplasmic Proteins/genetics/*physiology ; Plague/*microbiology ; Protein Stability ; Yersinia pestis/*physiology ; }, abstract = {Yersinia pestis biofilm formation, controlled by intracellular levels of the second messenger molecule cyclic diguanylate (c-di-GMP), is important for blockage-dependent plague transmission from fleas to mammals. HmsCDE is a tripartite signaling system that modulates intracellular c-di-GMP levels to regulate biofilm formation in Y. pestis. Previously, we found that Y. pestis biofilm formation is stimulated in reducing environments in an hmsCDE-dependent manner. However, the mechanism by which HmsCDE senses the redox state remains elusive. Using a dsbA mutant and the addition of Cu[2+] to simulate reducing and oxidizing periplasmic environments, we found that HmsC protein levels are decreased and the HmsC-HmsD protein-protein interaction is weakened in a reducing environment. In addition, we revealed that intraprotein disulphide bonds are critical for HmsC since breakage lowers protein stability and diminishes the interaction with HmsD. Our results suggest that HmsC might play a major role in sensing the environmental changes.}, } @article {pmid28848527, year = {2017}, author = {Kamaruzzaman, NF and Chong, SQY and Edmondson-Brown, KM and Ntow-Boahene, W and Bardiau, M and Good, L}, title = {Bactericidal and Anti-biofilm Effects of Polyhexamethylene Biguanide in Models of Intracellular and Biofilm of Staphylococcus aureus Isolated from Bovine Mastitis.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1518}, pmid = {28848527}, issn = {1664-302X}, abstract = {Staphylococcus aureus infection is a common cause of mastitis, reducing milk yield, affecting animal welfare and causing huge economic losses within the dairy industry. In addition to the problem of acquired drug resistance, bacterial invasion into udder cells and the formation of surface biofilms are believed to reduce antibiotic efficacy, leading to treatment failure. Here, we investigated the antimicrobial activities of enrofloxacin, an antibiotic that is commonly used in mastitis therapy and polyhexamethylene biguanide (PHMB), an antimicrobial polymer. The antimicrobial activities were tested against intracellular S. aureus in infected Mac-T cells (host cells). Also, fluorescein-tagged PHMB was used to study PHMB uptake and localization with S. aureus within the infected Mac-T cells. Anti-biofilm activities were tested by treating S. aureus biofilms and measuring effects on biofilm mass in vitro. Enrofloxacin and PHMB at 15 mg/L killed between 42 to 92 and 99.9% of intracellular S. aureus, respectively. PHMB-FITC entered and colocalized with the intracellular S. aureus, suggesting direct interaction of the drug with the bacteria inside the host cells. Enrofloxacin and PHMB at 15 mg/L reduced between 10 to 27% and 28 to 37% of biofilms' mass, respectively. The half-maximal inhibitory concentrations (IC50) obtained from a cytotoxicity assay were 345 ± 91 and 21 ± 2 mg/L for enrofloxacin and PHMB, respectively; therefore, both compounds were tolerated by the host cells at high concentrations. These findings suggest that both antimicrobials are effective against intracellular S. aureus and can disrupt biofilm structures, with PHMB being more potent against intracellular S. aureus, highlighting the potential application of PHMB in mastitis therapy.}, } @article {pmid28846821, year = {2017}, author = {Riga, EK and Vöhringer, M and Widyaya, VT and Lienkamp, K}, title = {Polymer-Based Surfaces Designed to Reduce Biofilm Formation: From Antimicrobial Polymers to Strategies for Long-Term Applications.}, journal = {Macromolecular rapid communications}, volume = {38}, number = {20}, pages = {}, pmid = {28846821}, issn = {1521-3927}, support = {637920/ERC_/European Research Council/International ; }, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Bacteria/drug effects/*growth & development ; Biofilms/*drug effects ; Polymers/*chemistry/pharmacology ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; }, abstract = {Contact-active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short-term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris. This layer shields incoming bacteria from the antimicrobially active cationic surface moieties. Besides discussing antimicrobial surfaces, this feature article focuses on recent strategies that were developed to overcome the contamination problem. This includes bifunctional materials with simultaneously presented antimicrobial and protein-repellent moieties; polymer surfaces that can be switched from an antimicrobial, cell-attractive to a cell-repellent state; polymer surfaces that can be regenerated by enzyme action; degradable antimicrobial polymers; and antimicrobial polymer surfaces with removable top layers.}, } @article {pmid28845576, year = {2018}, author = {Senpuku, H and Yonezawa, H and Yoneda, S and Suzuki, I and Nagasawa, R and Narisawa, N}, title = {SMU.940 regulates dextran-dependent aggregation and biofilm formation in Streptococcus mutans.}, journal = {Molecular oral microbiology}, volume = {33}, number = {1}, pages = {47-58}, doi = {10.1111/omi.12196}, pmid = {28845576}, issn = {2041-1014}, mesh = {Adhesins, Bacterial/*genetics/metabolism ; Bacterial Adhesion/genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Carrier Proteins/genetics/metabolism ; DNA Mutational Analysis ; Dextrans/*metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/*genetics ; Mutation ; Polysaccharides/analysis ; RNA, Bacterial/analysis ; Streptococcus mutans/*genetics/growth & development/*metabolism ; }, abstract = {The oral bacterium Streptococcus mutans is the principal agent in the development of dental caries. Biofilm formation by S. mutans requires bacterial attachment, aggregation, and glucan formation on the tooth surface under sucrose supplementation conditions. Our previous microarray analysis of clinical strains identified 74 genes in S. mutans that were related to biofilm morphology; however, the roles of almost all of these genes in biofilm formation are poorly understood. We investigated the effects of 21 genes randomly selected from our previous study regarding S. mutans biofilm formation, regulation by the complement pathway, and responses to competence-stimulating peptide. Eight competence-stimulating peptide-dependent genes were identified, and their roles in biofilm formation and aggregation were examined by mutational analyses of the S. mutansUA159 strain. Of these eight genes, the inactivation of the putative hemolysin III family SMU.940 gene of S. mutansUA159 promoted rapid dextran-dependent aggregation and biofilm formation in tryptic soy broth without dextrose (TSB) with 0.25% glucose and slightly reduced biofilm formation in TSB with 0.25% sucrose. The SMU.940 mutant showed higher expression of GbpC and gbpC gene than wild-type. GbpC is known to be involved in the dextran-dependent aggregation of S. mutans. An SMU.940-gbpC double mutant strain was constructed in the SMU.940 mutant background. The gbpC mutation completely abolished the dextran-dependent aggregation of the SMU.940 mutant. In addition, the aggregation of the mutant was abrogated by dextranase. These findings suggest that SMU.940 controls GbpC expression, and contributes to the regulation of dextran-dependent aggregation and biofilm formation.}, } @article {pmid28843119, year = {2017}, author = {Fu, Y and Deering, AJ and Bhunia, AK and Yao, Y}, title = {Biofilm of Escherichia coli O157:H7 on cantaloupe surface is resistant to lauroyl arginate ethyl and sodium hypochlorite.}, journal = {International journal of food microbiology}, volume = {260}, number = {}, pages = {11-16}, doi = {10.1016/j.ijfoodmicro.2017.08.008}, pmid = {28843119}, issn = {1879-3460}, mesh = {Arginine/*analogs & derivatives/pharmacology ; Biofilms/*growth & development ; Colony Count, Microbial ; Cucumis melo/*microbiology ; Escherichia coli O157/*drug effects/*growth & development ; Foodborne Diseases/microbiology/prevention & control ; Sodium Hypochlorite/*pharmacology ; }, abstract = {Biofilms formed by Escherichia coli O157:H7 on cantaloupe rind were characterized in this study. Cantaloupe rind pieces inoculated with E. coli O157:H7 B6-914 was sampled after 2, 12, and 24h incubation for imaging with cryo-scanning electron microscopy (Cryo-SEM) or treating with lauroyl arginate ethyl (LAE) or sodium hypochlorite (SHC). Cryo-SEM images showed that E. coli O157:H7 formed a biofilm within 12h on the rind surface. For rind samples treated with LAE or SHC, the residual cell counts were significantly different (p<0.05) between 2 and 12h incubation, and between 2 and 24h of incubation. For the 2h incubation samples, E. coli O157:H7 was undetectable (>5-log reduction) after treatment with 2000μg/mL of LAE or SHC. In contrast, for 12h incubation samples, 2000μg/mL of LAE or SHC could only achieve 1.74 or 1.86-log reduction, respectively. The study showed the low efficacy of LAE and SHC on cantaloupe rind surface to reduce the E. coli biofilm, suggesting the needs for cantaloupe cleaning methods beyond washing with conventional antimicrobial agents.}, } @article {pmid28842537, year = {2017}, author = {Lee, K and Lee, KM and Kim, D and Yoon, SS}, title = {Molecular Determinants of the Thickened Matrix in a Dual-Species Pseudomonas aeruginosa and Enterococcus faecalis Biofilm.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {21}, pages = {}, pmid = {28842537}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Enterococcus faecalis/chemistry/genetics/growth & development/*physiology ; Mutation ; Polysaccharides, Bacterial/chemistry/*metabolism ; Pseudomonas aeruginosa/chemistry/genetics/growth & development/*physiology ; }, abstract = {Biofilms are microbial communities that inhabit various surfaces and are surrounded by extracellular matrices (ECMs). Clinical microbiologists have shown that the majority of chronic infections are caused by biofilms, following the introduction of the first biofilm infection model by J. W. Costerton and colleagues (J. Lam, R. Chan, K. Lam, and J. W. Costerton, Infect Immun 28:546-556, 1980). However, treatments for chronic biofilm infections are still limited to surgical removal of the infected sites. Pseudomonas aeruginosa and Enterococcus faecalis are two frequently identified bacterial species in biofilm infections; nevertheless, the interactions between these two species, especially during biofilm growth, are not clearly understood. In this study, we observed phenotypic changes in a dual-species biofilm of P. aeruginosa and E. faecalis, including a dramatic increase in biofilm matrix thickness. For clear elucidation of the spatial distribution of the dual-species biofilm, P. aeruginosa and E. faecalis were labeled with red and green fluorescence, respectively. E. faecalis was located at the lower part of the dual-species biofilm, while P. aeruginosa developed a structured biofilm on the upper part. Mutants with altered exopolysaccharide (EPS) productions were constructed in order to determine the molecular basis for the synergistic effect of the dual-species biofilm. Increased biofilm matrix thickness was associated with EPSs, not extracellular DNA. In particular, Pel and Psl contributed to interspecies and intraspecies interactions, respectively, in the dual-species P. aeruginosa and E. faecalis biofilm. Accordingly, targeting Pel and Psl might be an effective part of eradicating P. aeruginosa polymicrobial biofilms.IMPORTANCE Chronic infection is a serious problem in the medical field. Scientists have observed that chronic infections are closely associated with biofilms, and the vast majority of infection-causing biofilms are polymicrobial. Many studies have reported that microbes in polymicrobial biofilms interact with each other and that the bacterial interactions result in elevated virulence, in terms of factors, such as infectivity and antibiotic resistance. Pseudomonas aeruginosa and Enterococcus faecalis are frequently isolated pathogens in chronic biofilm infections. Nevertheless, while both bacteria are known to be agents of numerous nosocomial infections and can cause serious diseases, interactions between the bacteria in biofilms have rarely been examined. In this investigation, we aimed to characterize P. aeruginosa and E. faecalis dual-species biofilms and to determine the molecular factors that cause synergistic effects, especially on the matrix thickening of the biofilm. We suspect that our findings will contribute to the development of more efficient methods for eradicating polymicrobial biofilm infections.}, } @article {pmid28841790, year = {2017}, author = {Roy, D and McEvoy, J and Blonigen, M and Amundson, M and Khan, E}, title = {Seasonal variation and ex-situ nitrification activity of ammonia oxidizing archaea in biofilm based wastewater treatment processes.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 1}, pages = {850-859}, doi = {10.1016/j.biortech.2017.08.060}, pmid = {28841790}, issn = {1873-2976}, mesh = {Ammonia ; *Archaea ; Bacteria ; Biofilms ; *Nitrification ; Oxidation-Reduction ; Phylogeny ; Seasons ; *Wastewater ; }, abstract = {The abundance of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) was investigated in full-scale two-stage trickling filters (TF) and moving bed bioreactor (MBBR) treating municipal wastewater. Biofilm samples were collected for 17months from nitrifying TF (NTF), biochemical oxygen demand TF (BTF), and MBBR media. The abundance of AOA and AOB was determined using a quantitative PCR approach targeting the ammonia monooxygenase subunit A gene of archaea and bacteria. AOA were dominant in the NTF and MBBR, while AOB dominated in the BTF. AOA and AOB were more abundant during warmer months, and AOA were detected in the BTF only during warmer months. In laboratory nitrification activity experiments, ammonia oxidation to nitrite decreased when AOA populations from the NTF and MBBR were inhibited, demonstrating that AOA contributed to nitrification. This study has shown that AOA outnumber AOB and contribute to ammonia oxidation in full-scale nitrifying biofilm processes.}, } @article {pmid28841717, year = {2017}, author = {Shenoy, AT and Brissac, T and Gilley, RP and Kumar, N and Wang, Y and Gonzalez-Juarbe, N and Hinkle, WS and Daugherty, SC and Shetty, AC and Ott, S and Tallon, LJ and Deshane, J and Tettelin, H and Orihuela, CJ}, title = {Streptococcus pneumoniae in the heart subvert the host response through biofilm-mediated resident macrophage killing.}, journal = {PLoS pathogens}, volume = {13}, number = {8}, pages = {e1006582}, pmid = {28841717}, issn = {1553-7374}, support = {K12 GM088010/GM/NIGMS NIH HHS/United States ; R01 AI114800/AI/NIAID NIH HHS/United States ; R01 HL128502/HL/NHLBI NIH HHS/United States ; T32 AI007051/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Blotting, Western ; Disease Models, Animal ; Female ; Flow Cytometry ; Fluorescent Antibody Technique ; Gene Expression Profiling ; Macrophages/*immunology ; Mice ; Mice, Inbred BALB C ; Microscopy, Electron, Transmission ; Myocarditis/*immunology/*microbiology ; Pneumococcal Infections/genetics/*immunology ; Principal Component Analysis ; Streptococcus pneumoniae/genetics/immunology ; *Transcriptome ; Virulence/genetics/immunology ; }, abstract = {For over 130 years, invasive pneumococcal disease has been associated with the presence of extracellular planktonic pneumococci, i.e. diplococci or short chains in affected tissues. Herein, we show that Streptococcus pneumoniae that invade the myocardium instead replicate within cellular vesicles and transition into non-purulent biofilms. Pneumococci within mature cardiac microlesions exhibited salient biofilm features including intrinsic resistance to antibiotic killing and the presence of an extracellular matrix. Dual RNA-seq and subsequent principal component analyses of heart- and blood-isolated pneumococci confirmed the biofilm phenotype in vivo and revealed stark anatomical site-specific differences in virulence gene expression; the latter having major implications on future vaccine antigen selection. Our RNA-seq approach also identified three genomic islands as exclusively expressed in vivo. Deletion of one such island, Region of Diversity 12, resulted in a biofilm-deficient and highly inflammogenic phenotype within the heart; indicating a possible link between the biofilm phenotype and a dampened host-response. We subsequently determined that biofilm pneumococci released greater amounts of the toxin pneumolysin than did planktonic or RD12 deficient pneumococci. This allowed heart-invaded wildtype pneumococci to kill resident cardiac macrophages and subsequently subvert cytokine/chemokine production and neutrophil infiltration into the myocardium. This is the first report for pneumococcal biofilm formation in an invasive disease setting. We show that biofilm pneumococci actively suppress the host response through pneumolysin-mediated immune cell killing. As such, our findings contradict the emerging notion that biofilm pneumococci are passively immunoquiescent.}, } @article {pmid28840968, year = {2017}, author = {Martirani-Von Abercron, SM and Marín, P and Solsona-Ferraz, M and Castañeda-Cataña, MA and Marqués, S}, title = {Naphthalene biodegradation under oxygen-limiting conditions: community dynamics and the relevance of biofilm-forming capacity.}, journal = {Microbial biotechnology}, volume = {10}, number = {6}, pages = {1781-1796}, pmid = {28840968}, issn = {1751-7915}, mesh = {Bacteria/classification/genetics/isolation & purification/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Groundwater/analysis/microbiology ; Naphthalenes/*metabolism ; Nitrates/metabolism ; Oxygen/*metabolism ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Toxic polycyclic aromatic hydrocarbons (PAHs) are frequently released into the environment from anthropogenic sources. PAH remediation strategies focus on biological processes mediated by bacteria. The availability of oxygen in polluted environments is often limited or absent, and only bacteria able to thrive in these conditions can be considered for bioremediation strategies. To identify bacterial strains able to degrade PAHs under oxygen-limiting conditions, we set up enrichment cultures from samples of an oil-polluted aquifer, using either anoxic or microaerophilic condition and with PAHs as the sole carbon source. Despite the presence of a significant community of nitrate-reducing bacteria, the initial community, which was dominated by Betaproteobacteria, was incapable of PAH degradation under strict anoxic conditions, although a clear shift in the structure of the community towards an increase in the Alphaproteobacteria (Sphingomonadaceae), Actinobacteria and an uncultured group of Acidobacteria was observed in the enrichments. In contrast, growth under microaerophilic conditions with naphthalene as the carbon source evidenced the development of a biofilm structure around the naphthalene crystal. The enrichment process selected two co-dominant groups which finally reached 97% of the bacterial communities: Variovorax spp. (54%, Betaproteobacteria) and Starkeya spp. (43%, Xanthobacteraceae). The two dominant populations were able to grow with naphthalene, although only Starkeya was able to reproduce the biofilm structure around the naphthalene crystal. The pathway for naphthalene degradation was identified, which included as essential steps dioxygenases with high affinity for oxygen, showing 99% identity with Xanthobacter polyaromaticivorans dbd cluster for PAH degradation. Our results suggest that the biofilm formation capacity of Starkeya provided a structure to allocate its cells at an appropriate distance from the toxic carbon source.}, } @article {pmid28840961, year = {2017}, author = {Matilla, MA}, title = {A technology for the investigation of biofilm transmission under shearing pressures.}, journal = {Microbial biotechnology}, volume = {10}, number = {6}, pages = {1451-1453}, pmid = {28840961}, issn = {1751-7915}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Biomechanical Phenomena ; Biophysics/*methods ; Staphylococcus/chemistry/genetics/*physiology ; }, abstract = {Biofilm formation is a multifactorial and dynamic process. Stages of biofilm formation are highly regulated and include bacterial attachment to a target surface, formation of microcolonies, biofilm maturation and dispersion. This article highlights recent research by Gusnaniar et al., () in which the authors develop a device to investigate bacterial biofilm transmission between surfaces under shearing pressures. The instrument can potentially be used to investigate the role of different genetic determinants and environmental cues on biofilm stability and transmission.}, } @article {pmid28839494, year = {2017}, author = {Lima-E-Silva, AA and Silva-Filho, RG and Fernandes, HMZ and Saramago, CSM and Viana, AS and Souza, MJ and Nogueira, EM}, title = {Sub-Inhibitory Concentrations of Rifampicin Strongly Stimulated Biofilm Production in S. aureus.}, journal = {The open microbiology journal}, volume = {11}, number = {}, pages = {142-151}, pmid = {28839494}, issn = {1874-2858}, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus aureus is an important pathogen and a frequent cause of infections associated with biofilm production in implantable medical devices. Biofilm production can be induced by sub-inhibitory concentrations (sub-MICs) of certain antibiotics, but few studies have researched this occurrence in S. aureus. In this study, we investigated the effect of sub-MICs of rifampicin and minocycline on biofilm production by five clinical and five non-clinical S. aureus isolates.

METHODS: Microtiter Plate assay and Congo Red Agar Test were used to analyze the biofilm production. The biofilm composition was evaluated by the detachment assay with sodium metaperiodate and proteinase K.

RESULTS: Rifampicin sub-MICs induced very high biofilm formation in seven isolates that were non-producers in Tryptic Soy Broth. In one producer isolate, the biofilm formation level was not affected by sub-MICs of this drug. Sub-MICs of minocycline did not induce biofilm production in all isolates tested and in two producer isolates, instead, MIC/2 and MIC/4 inhibited biofilm production. The results of the drugs in combination were similar to those with rifampicin alone. The biofilm matrix was identified as polysaccharide, except for one producer isolate, classified as proteinaceous. Polysaccharide biofilm producer isolates, when grown on Congo Red Agar without sucrose, but with sub-MICs of rifampicin, showed results in agreement with those obtained in Microtiter Plate Test.

CONCLUSION: The high biofilm production induced by sub-MICs of rifampicin has potential clinical relevance, because this is one of the drugs commonly used in the impregnation of catheters. In addition, it is used adjunctively to treat certain S. aureus infections.}, } @article {pmid28839480, year = {2017}, author = {Chenicheri, S and R, U and Ramachandran, R and Thomas, V and Wood, A}, title = {Insight into Oral Biofilm: Primary, Secondary and Residual Caries and Phyto-Challenged Solutions.}, journal = {The open dentistry journal}, volume = {11}, number = {}, pages = {312-333}, pmid = {28839480}, issn = {1874-2106}, abstract = {INTRODUCTION: Dental caries is known to be one of the most widespread, chronic infections affecting all ages and populations worldwide. The plethora of oral microbial population paves way for various endogenous infections and plays a crucial role in polymicrobial interactions contributing to biofilm-mediated diseases like caries and periodontal diseases.

METHODS: Extensive literature survey was conducted using the scientific databases like PubMed, Google scholar, Science Direct, etc. using the key words like dental caries, orodental infections, dental microbes, dental biofilm, secondary caries, phytotherapy, etc. The literature was analyzed thoroughly and critical review was performed.

RESULTS: The risk of development of secondary caries and residual caries further results in treatment failure. Drug resistance developed by oral microbes and further side effects pose serious hurdles in the current therapeutic strategies. The hyperactivities of various MMPs and the resulting massive ECM degradation are the challenging part in the design of effective therapeutic approaches. Anticariogenic phytotherapy is well appreciated owing to lesser side effects and versatility of their action. But appreciable outcomes regarding the phytochemical bioavailability and bioretention are still challenging. Site-specific delivery of phytoagents at the infected site may enhance the efficiency of these drugs. Accordingly emerging phytodentistry can be promising for the management of secondary and residual caries.

CONCLUSION: This article presents major cariogens and their mechanisms in initiating and aggravating dental caries. Effectiveness of phytotherapy and different mode of action of phytochemicals against cariogens are outlined. The article also raises major concerns and possibilities of phytochemical based therapeutics to be applied in the clinical arena of caries management.}, } @article {pmid28835649, year = {2017}, author = {Yan, J and Nadell, CD and Stone, HA and Wingreen, NS and Bassler, BL}, title = {Extracellular-matrix-mediated osmotic pressure drives Vibrio cholerae biofilm expansion and cheater exclusion.}, journal = {Nature communications}, volume = {8}, number = {1}, pages = {327}, pmid = {28835649}, issn = {2041-1723}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Extracellular Matrix/*metabolism ; Microscopy, Confocal ; Mutation ; *Osmotic Pressure ; Vibrio cholerae/genetics/metabolism/*physiology ; }, abstract = {Biofilms, surface-attached communities of bacteria encased in an extracellular matrix, are a major mode of bacterial life. How the material properties of the matrix contribute to biofilm growth and robustness is largely unexplored, in particular in response to environmental perturbations such as changes in osmotic pressure. Here, using Vibrio cholerae as our model organism, we show that during active cell growth, matrix production enables biofilm-dwelling bacterial cells to establish an osmotic pressure difference between the biofilm and the external environment. This pressure difference promotes biofilm expansion on nutritious surfaces by physically swelling the colony, which enhances nutrient uptake, and enables matrix-producing cells to outcompete non-matrix-producing cheaters via physical exclusion. Osmotic pressure together with crosslinking of the matrix also controls the growth of submerged biofilms and their susceptibility to invasion by planktonic cells. As the basic physicochemical principles of matrix crosslinking and osmotic swelling are universal, our findings may have implications for other biofilm-forming bacterial species.Most bacteria live in biofilms, surface-attached communities encased in an extracellular matrix. Here, Yan et al. show that matrix production in Vibrio cholerae increases the osmotic pressure within the biofilm, promoting biofilm expansion and physical exclusion of non-matrix producing cheaters.}, } @article {pmid28833086, year = {2017}, author = {Kundu, P and Dutta, D and Kumar Das, A}, title = {The α1β1 region is crucial for biofilm enhancement activity of MTC28 in Mycobacterium smegmatis.}, journal = {FEBS letters}, volume = {591}, number = {20}, pages = {3333-3347}, doi = {10.1002/1873-3468.12823}, pmid = {28833086}, issn = {1873-3468}, mesh = {Amino Acid Sequence ; Antigens, Bacterial/*chemistry/genetics/*pharmacology ; Antitubercular Agents/pharmacology ; Bacterial Proteins/*chemistry/genetics/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Wall/drug effects/metabolism ; Cloning, Molecular ; Drug Resistance, Bacterial/genetics ; Escherichia coli/genetics/metabolism ; Gene Expression ; Hydrophobic and Hydrophilic Interactions ; Isoniazid/pharmacology ; Kinetics ; Models, Molecular ; Mycobacterium smegmatis/*drug effects/genetics/growth & development/metabolism ; Mycobacterium tuberculosis/genetics/growth & development/*metabolism ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Recombinant Proteins/chemistry/genetics/metabolism/pharmacology ; Sequence Alignment ; Structure-Activity Relationship ; Triclosan/pharmacology ; }, abstract = {We show here that MTC28, a secretory antigen of 28 kDa from Mycobacterium tuberculosis, is involved in biofilm formation. The exogenous addition of MTC28 to the culture medium as well its expression in Mycobacterium smegmatis mc[2] 155 shows an enhancement in biofilm formation, which leads to drug resistance. Structural analysis of MTC28 followed by mutational studies confirms the role of its α1β1 region in the biofilm enhancement activity. Confocal and flow cytometry studies show that the α1β1 region of MTC28 is crucial for binding to the M. smegmatis cell wall. The enhancement in biofilm formation due to MTC28 is also observed in M. tuberculosis H37Ra. This is the first report on the structure-function relationship of MTC28.}, } @article {pmid28833013, year = {2017}, author = {Harris, V and Smith, SD}, title = {Lifting the biofilm lid on the antibacterial and antibiofilm effects of sodium hypochlorite against Staphylococcus aureus in atopic dermatitis.}, journal = {The British journal of dermatology}, volume = {177}, number = {2}, pages = {347-348}, doi = {10.1111/bjd.15692}, pmid = {28833013}, issn = {1365-2133}, mesh = {*Anti-Bacterial Agents ; Biofilms/drug effects ; Dermatitis, Atopic/*microbiology ; Humans ; Sodium Hypochlorite ; Staphylococcus aureus/*drug effects ; }, } @article {pmid28831068, year = {2017}, author = {Kiran, GS and Jackson, SA and Priyadharsini, S and Dobson, ADW and Selvin, J}, title = {Synthesis of Nm-PHB (nanomelanin-polyhydroxy butyrate) nanocomposite film and its protective effect against biofilm-forming multi drug resistant Staphylococcus aureus.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {9167}, pmid = {28831068}, issn = {2045-2322}, mesh = {Animals ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Food Packaging ; Hydroxybutyrates/*chemistry ; Melanins/chemistry/isolation & purification/*pharmacology ; Nanocomposites/chemistry ; Particle Size ; Phylogeny ; Porifera/microbiology ; Pseudomonas/classification/metabolism ; Staphylococcus aureus/drug effects/*physiology ; X-Ray Diffraction ; }, abstract = {Melanin is a dark brown ubiquitous photosynthetic pigment which have many varied and ever expanding applications in fabrication of radio-protective materials, food packaging, cosmetics and in medicine. In this study, melanin production in a Pseudomonas sp. which was isolated from the marine sponge Tetyrina citirna was optimized employing one-factor at a time experiments and characterized for chemical nature and stability. Following sonication nucleated nanomelanin (Nm) particles were formed and evaluated for antibacterial and antioxidant properties. Nanocomposite film was fabricated using combinations (% w/v) of polyhydroxy butyrate-nanomelanin (PHB:Nm) blended with 1% glycerol. The Nm was found to be spherical in shape with a diameter of 100-140 nm and showed strong antimicrobial activity against both Gram positive and Gram negative bacteria. The Nm-PHB nanocomposite film was homogeneous, smooth, without any cracks, and flexible. XRD and DSC data indicated that the film was crystalline in nature, and was thermostable up to 281.87 °C. This study represents the first report on the synthesis of Nm and fabrication of Nm-PHB nanocomposite film which show strong protective effect against multidrug resistant Staphyloccoccus aureus. Thus this Nm-PHB nanocomposite film may find utility as packaging material for food products by protecting the food products from oxidation and bacterial contamination.}, } @article {pmid28828348, year = {2017}, author = {Prasad, UV and Vasu, D and Gowtham, RR and Pradeep, CK and Swarupa, V and Yeswanth, S and Choudhary, A and Sarma, PVGK}, title = {Cloning, Expression and Characterization of NAD Kinase from Staphylococcus aureus Involved in the Formation of NADP (H): A Key Molecule in the Maintaining of Redox Status and Biofilm Formation.}, journal = {Advanced biomedical research}, volume = {6}, number = {}, pages = {97}, pmid = {28828348}, issn = {2277-9175}, abstract = {BACKGROUND: Staphylococcus aureus has the ability to form biofilms on any niches, a key pathogenic factor of this organism and this phenomenon is directly related to the concentration of NADPH. The formation of NADP is catalyzed by NAD kinase (NADK) and this gene of S. aureus ATCC 12600 was cloned, sequenced, expressed and characterized.

MATERIALS AND METHODS: The NADK gene was polymerase chain reaction amplified from the chromosomal DNA of S. aureus ATCC 12600 and cloned in pQE 30 vector, sequenced and expressed in Escherichia coli DH5α. The pure protein was obtained by passing through nickel metal chelate agarose column. The enzyme kinetics of the enzyme and biofilm assay of the S. aureus was carried out in both aerobic and anaerobic conditions. The kinetics was further confirmed by the ability of the substrates to dock to the NADK structure.

RESULTS: The recombinant NADK exhibited single band with a molecular weight of 31kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gene sequence (GenBank: JN645814) revealed presence of only one kind of NADK in all S. aureus strains. The enzyme exhibited very high affinity for NAD compared to adenosine triphosphate concurring with the docking results. A root-mean-square deviation value 14.039Å observed when NADK structure was superimposed with its human counterpart suggesting very low homology. In anaerobic conditions, higher biofilm units were found with decreased NADK activity.

CONCLUSION: The results of this study suggest increased NADPH concentration in S. aureus plays a vital role in the biofilm formation and survival of this pathogen in any environmental conditions.}, } @article {pmid28828247, year = {2017}, author = {Tomczyk-Żak, K and Szczesny, P and Gromadka, R and Zielenkiewicz, U}, title = {Taxonomic and chemical assessment of exceptionally abundant rock mine biofilm.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e3635}, pmid = {28828247}, issn = {2167-8359}, abstract = {BACKGROUND: An exceptionally thick biofilm covers walls of ancient gold and arsenic Złoty Stok mine (Poland) in the apparent absence of organic sources of energy.

METHODS AND RESULTS: We have characterized this microbial community using culture-dependent and independent methods. We sequenced amplicons of the 16S rRNA gene obtained using generic primers and additional primers targeted at Archaea and Actinobacteria separately. Also, we have cultured numerous isolates from the biofilm on different media under aerobic and anaerobic conditions. We discovered very high biodiversity, and no single taxonomic group was dominant. The majority of almost 4,000 OTUs were classified above genus level indicating presence of novel species. Elemental analysis, performed using SEM-EDS and X-ray, of biofilm samples showed that carbon, sulphur and oxygen were not evenly distributed in the biofilm and that their presence is highly correlated. However, the distribution of arsenic and iron was more flat, and numerous intrusions of elemental silver and platinum were noted, indicating that microorganisms play a key role in releasing these elements from the rock.

CONCLUSIONS: Altogether, the picture obtained throughout this study shows a very rich, complex and interdependent system of rock biofilm. The chemical heterogeneity of biofilm is a likely explanation as to why this oligotrophic environment is capable of supporting such high microbial diversity.}, } @article {pmid28828153, year = {2017}, author = {Akkus, A and Tyler, R and Schiraldi, D and Roperto, R and Faddoul, F and Teich, S}, title = {Effect of polyethelene oxide on the thermal degradation of cellulose biofilm - Low cost material for soft tissue repair in dentistry.}, journal = {Journal of clinical and experimental dentistry}, volume = {9}, number = {7}, pages = {e875-e878}, pmid = {28828153}, issn = {1989-5488}, abstract = {BACKGROUND: Bio cellulose is a byproduct of sweet tea fermentation known as kombusha. During the biosynthesis by bacteria cellulose chains are polymerized by enzyme from activated glucose. The single chains are then extruded through the bacterial cell wall. Interestingly, a potential of the Kombucha's byproduct bio cellulose (BC) as biomaterial had come into focus only in the past few decades. The unique physical and mechanical properties such as high purity, an ultrafine and highly crystalline network structure, a superior mechanical strength, flexibility, pronounced permeability to gases and liquids, and an excellent compatibility with living tissue that reinforced by biodegradability, biocompatibility, large swelling ratios.

MATERIAL AND METHODS: The bio-cellulose film specimens were provided by the R.P Dressel dental materials laboratory, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, US. The films were harvested, washed with water and dried at room temperature overnight. 1wt% of PEG-2000 and 10wt% of NaOH were added into ultrapure water to prepare PEG/NaOH solution. Then bio-cellulose film was added to the mixture and swell for 3 h at room temperature. All bio-cellulose film specimens were all used in the TA Instruments Q500 Thermogravmetric Analyzer to investigate weight percent lost and degradation. The TGA was under ambient air conditions at a heating rate of 10ºC/min.

RESULTS AND CONCLUSIONS: PEG control exhibited one transition with the peak at 380ºC. Cellulose and cellulose/ PEG films showed 3 major transitions. Interestingly, the cellulose/PEG film showed slightly elevated temperatures when compared to the corresponding transitions for cellulose control. The thermal gravimetric analysis (TGA) degradation curves were analyzed. Cellulose control film exhibited two zero order transitions, that indicate the independence of the rate of degradation from the amount on the initial substance. The activation energies for three transitions for cellulose and cellulose/PEG showed increasingly higher values for the transitions at higher temperatures. Key words:TGA, Bio-cellulose, PEG.}, } @article {pmid28827313, year = {2017}, author = {Sobe, RC and Bond, WG and Wotanis, CK and Zayner, JP and Burriss, MA and Fernandez, N and Bruger, EL and Waters, CM and Neufeld, HS and Karatan, E}, title = {Spermine inhibits Vibrio cholerae biofilm formation through the NspS-MbaA polyamine signaling system.}, journal = {The Journal of biological chemistry}, volume = {292}, number = {41}, pages = {17025-17036}, pmid = {28827313}, issn = {1083-351X}, support = {R01 GM109259/GM/NIGMS NIH HHS/United States ; R15 AI096358/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Cyclic GMP/analogs & derivatives/metabolism ; Humans ; Intestinal Mucosa/metabolism ; Intestines/microbiology ; Models, Biological ; *Periplasmic Proteins/chemistry/metabolism ; *Phosphoric Diester Hydrolases/chemistry/metabolism ; Signal Transduction/*drug effects ; Spermine/*pharmacology ; *Vibrio cholerae/chemistry/physiology ; }, abstract = {The aquatic bacterium and human intestinal pathogen, Vibrio cholerae, senses and responds to a variety of environment-specific cues to regulate biofilm formation. Specifically, the polyamines norspermidine and spermidine enhance and repress V. cholerae biofilm formation, respectively. These effects are relevant for understanding V. cholerae pathogenicity and are mediated through the periplasmic binding protein NspS and the transmembrane bis-(3'-5') cyclic diguanosine monophosphate (c-di-GMP) phosphodiesterase MbaA. However, the levels of spermidine required to inhibit biofilm formation through this pathway are unlikely to be encountered by V. cholerae in aquatic reservoirs or within the human host during infection. We therefore hypothesized that other polyamines in the gastrointestinal tract may control V. cholerae biofilm formation at physiological levels. The tetramine spermine has been reported to be present at nearly 50 μm concentrations in the intestinal lumen. Here, we report that spermine acts as an exogenous cue that inhibits V. cholerae biofilm formation through the NspS-MbaA signaling system. We found that this effect probably occurs through a direct interaction of spermine with NspS, as purified NspS protein could bind spermine in vitro Spermine also inhibited biofilm formation by altering the transcription of the vps genes involved in biofilm matrix production. Global c-di-GMP levels were unaffected by spermine supplementation, suggesting that biofilm formation may be regulated by variations in local rather than global c-di-GMP pools. Finally, we propose a model illustrating how the NspS-MbaA signaling system may communicate exogenous polyamine content to the cell to control biofilm formation in the aquatic environment and within the human intestine.}, } @article {pmid28827106, year = {2018}, author = {Hobbs, T and Schultz, LN and Lauchnor, EG and Gerlach, R and Lange, D}, title = {Evaluation of Biofilm Induced Urinary Infection Stone Formation in a Novel Laboratory Model System.}, journal = {The Journal of urology}, volume = {199}, number = {1}, pages = {178-185}, doi = {10.1016/j.juro.2017.08.083}, pmid = {28827106}, issn = {1527-3792}, mesh = {*Biofilms ; Humans ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Models, Biological ; Proteus mirabilis ; Urinary Calculi/*microbiology ; Urinary Tract Infections/*microbiology ; X-Ray Diffraction ; }, abstract = {PURPOSE: Infection stones, which comprise approximately 15% of all urinary tract stones, are induced by infection with urease-positive pathogens. The bacteria in the stone matrix present significant treatment impediments compared to metabolic kidney stones. While much is known about how urinary composition regulates metabolic stone formation, there is a general lack of knowledge of which urinary factors regulate the rate of infection stone formation. Unfortunately more in-depth research into infection stones is limited by the lack of suitable models for real-time study of bacterial biofilm formation and stone formation under varying conditions.

MATERIALS AND METHODS: We developed an in vitro model to study infection stone formation. The model closely represents the processes that occur in vivo, including the observed migration of ureolytic bacteria (our culture of Proteus mirabilis) from the bladder to the kidneys, followed by biofilm and stone formation in the kidney. We used scanning electron and confocal laser microscopy, x-ray diffraction, biological counts and dissolved chemical analyses to evaluate the model system.

RESULTS: Crystals that formed in the system resembled clinically removed struvite stones in structure and composition. Results showed that the degree of ureolysis required to significantly change urine pH was minimal, bacterial communities inhabited the ureter, and upstream colonization and struvite formation required lag time.

CONCLUSIONS: These results have implications for the detection and treatment of struvite stones. Currently this model is being used to study specific urinary factors that regulate struvite formation to identify treatment options, which combined with antibiotics would improve treatment of these stones and decrease recurrence.}, } @article {pmid28826769, year = {2017}, author = {Raavi, and Mishra, S and Singh, S}, title = {Prevention of OprD regulated antibiotic resistance in Pseudomonas aeruginosa biofilm.}, journal = {Microbial pathogenesis}, volume = {112}, number = {}, pages = {221-229}, doi = {10.1016/j.micpath.2017.08.007}, pmid = {28826769}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/growth & development ; Carbapenems/pharmacology ; Catalytic Domain ; Computer Simulation ; Drug Resistance, Bacterial/drug effects/*physiology ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Models, Molecular ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Porins/chemistry/*metabolism ; Protein Conformation ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/drug effects/*metabolism ; Signal Transduction ; Trans-Activators ; }, abstract = {In P.aeruginosa biofilms, the issue of antibiotic resistance is of particular importance due to increasing number of infections being reported in medical implants. The current study is focused on CzcR and CopR proteins which are part of two-component signal transduction systems (TCSs) - CzcR-CzcS and CopR-CopS respectively in P.aeruginosa. They both negatively regulate OprD porin expression which affects the intake of antibiotics like carbapenems. These two proteins can be treated as targets to combat antibiotic resistance in P.aeruginosa. Docking was performed on these proteins in search of inhibitors against the CzcR-CzcS and CopR-CopS TCSs. Efficient inhibitory ligands were evaluated on the basis of least binding energy, human oral absorption and ADME properties using a four-tier structure based virtual screening. The resulting ligands displayed high effective inhibitory property and satisfactory pharmacokinetics as compared to inhibitors which have been identified before for two-component signal transduction systems for gram negative bacteria. These potential inhibitors can now be used further in wet lab by performing selectivity assays to determine their inhibition rate against P.aeruginosa biofilms. Identification of potential leads may enable the development of new therapeutic strategies aimed at disrupting P.aeruginosabiofilms.}, } @article {pmid28826725, year = {2017}, author = {Sommerfeld Ross, S and Gharse, S and Sanchez, L and Fiegel, J}, title = {Dry powder aerosols to co-deliver antibiotics and nutrient dispersion compounds for enhanced bacterial biofilm eradication.}, journal = {International journal of pharmaceutics}, volume = {531}, number = {1}, pages = {14-23}, pmid = {28826725}, issn = {1873-3476}, support = {S10 RR022498/RR/NCRR NIH HHS/United States ; P30 ES005605/ES/NIEHS NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; R21 AI096007/AI/NIAID NIH HHS/United States ; UL1 RR024979/RR/NCRR NIH HHS/United States ; }, mesh = {Administration, Inhalation ; *Aerosols ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects ; Chemistry, Pharmaceutical ; Dry Powder Inhalers ; Particle Size ; *Powders ; Pseudomonas aeruginosa/drug effects ; }, abstract = {The purpose of this study was to formulate a dry powder for inhalation containing a combination treatment for eradication of Pseudomonas aeruginosa bacterial biofilms. Dry powders containing an antibiotic (ciprofloxacin hydrochloride, CH) and nutrient dispersion compound (glutamic acid, GA) at a ratio determined to eliminate the biofilms were generated by spray drying. Leucine was added to the spray dried formulation to aid powder flowability. A central composite design of experiments was performed to determine the effects of solution and processing parameters on powder yield and aerodynamic properties. Combinations of CH and GA eradicated bacterial biofilms at lower antibiotic concentrations compared to CH alone. Spray dried powders were produced with yields up to 43% and mass mean aerodynamic diameters (MMAD) in the respirable range. Powder yield was primarily affected by variables that determine cyclone efficiency, i.e. atomizer and solution flow rates and solution concentration; while MMAD was mainly determined by solution concentration. Fine particle fractions (FPF)<4.46μm and <2.82μm of the powders ranged from 56 to 70% and 35 to 46%, respectively. This study demonstrates that dry powder aerosols containing high concentrations of a combination treatment effective against P. aeruginosa biofilms could be developed with high yield, aerodynamic properties appropriate for inhalation, and no loss of potency.}, } @article {pmid28826573, year = {2017}, author = {Harris, LG and Dudley, E and Rohde, H and Frommelt, L and Siemssen, N and Wilkinson, TS and Mack, D}, title = {Limitations in the use of PSMγ, agr, RNAIII, and biofilm formation as biomarkers to define invasive Staphylococcus epidermidis from chronic biomedical device-associated infections.}, journal = {International journal of medical microbiology : IJMM}, volume = {307}, number = {7}, pages = {382-387}, doi = {10.1016/j.ijmm.2017.08.003}, pmid = {28826573}, issn = {1618-0607}, mesh = {Bacterial Proteins/analysis/genetics/physiology ; Bacterial Toxins/analysis/genetics/metabolism ; Biofilms/*growth & development ; Biomarkers ; Catheter-Related Infections/*microbiology ; Prosthesis-Related Infections/*microbiology ; RNA, Bacterial/analysis/genetics/physiology ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/pathogenicity/*physiology ; }, abstract = {Staphylococcus epidermidis is a common cause of biomedical device-associated infections. Agr is the major quorum sensing system in staphylococci and regulates virulence factors. Four agr-specificity groups exist in S. epidermidis, and chronic S. epidermidis infections are hypothesised to select for agr-negative phenotypes. Therefore, we investigated S. epidermidis strains from prosthetic joint- and catheter-associated infections to establish i) whether an infection selects for an agr-negative phenotype; ii) the importance of PSMγ and iii) if the agr-specificity group is infection dependent. S. epidermidis nasal isolates from healthy volunteers were used as controls. The distribution of agr-specificity groups was significantly different between infection and control episodes, but did not distinguish between the infection types. PSMγ secretion was used to determine agr-activity and HPLC analysis showed that 44% of prosthetic and 32% of catheter-associated episodes produced no PSMγ in comparison to 8% of the control strains. However, PSMγ expression did not always correlate with RNAIII up-regulation, indicating that PSMγ synthesis is likely influenced by additional post-transcriptional control. The data suggests chronic S. epidermidis infections favour agr-specificity group 1 but the results suggest that they do not select for an agr-negative phenotype. Further studies are required to explore the mechanisms underlying the selection and survival of these S. epidermidis phenotypes isolated from biomedical device-associated infections.}, } @article {pmid28826250, year = {2018}, author = {Dong, G and Liu, H and Yu, X and Zhang, X and Lu, H and Zhou, T and Cao, J}, title = {Antimicrobial and anti-biofilm activity of tannic acid against Staphylococcus aureus.}, journal = {Natural product research}, volume = {32}, number = {18}, pages = {2225-2228}, doi = {10.1080/14786419.2017.1366485}, pmid = {28826250}, issn = {1478-6427}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects ; Tannins/*pharmacology/therapeutic use ; }, abstract = {Tannic acid, a rich of natural and process-derived phenolic compound, has been shown to be an effective antagonist against viruses and bacteria. In this study, we determined the antimicrobial activity and mechanisms of tannic acid against Staphylococcus aureus with emphasis on inhibiting effect on biofilm formation. Based on the results of time-kill assay, binding ability assay, lysozyme susceptibility assay and the transmission electron microscope, we tentatively speculated that peptidoglycan might be the target of the process that tannic acid destroy the integrity of cell wall, moreover, tannic acid could reduce the biofilm formation at sub-MIC concentrations. These results manifested that natural product tannic acid could serve as a potentially effective candidate for development of novel strategies to treat methicillin-resistant S. aureus infections.}, } @article {pmid28826057, year = {2018}, author = {Zhong, Y and Yang, Q and Fu, G and Xu, Y and Cheng, Y and Chen, C and Xiang, R and Wen, T and Li, X and Zeng, G}, title = {Denitrifying microbial community with the ability to bromate reduction in a rotating biofilm-electrode reactor.}, journal = {Journal of hazardous materials}, volume = {342}, number = {}, pages = {150-157}, doi = {10.1016/j.jhazmat.2017.08.019}, pmid = {28826057}, issn = {1873-3336}, mesh = {Actinobacteria/chemistry/*genetics ; Bacillus/chemistry/*genetics ; Bacteria/chemistry/*genetics ; Biofilms ; Bromates/*chemistry ; Denitrification ; Electrodes ; Nitrates/*chemistry ; Phylogeny ; Proteobacteria/chemistry/*genetics ; RNA, Ribosomal, 16S/chemistry/*genetics ; }, abstract = {In this study, the microbial community for bromate reduction in a rotating biofilm-electrode reactor (RBER) was investigated. Continuous experiment demonstrated that the bromate reduction by an auto-hydrogenotrophic microbial community was inhibited by high concentration nitrate (50mg/L). The bacterial diversity of RBER were examined through the analyse of 16S rRNA gene sequences of clone libraries. The results showed that the bromate-reducing bacteria were phylogenetically diverse at the phylum level, representing the Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. The relative abundances of these microbial community represented 99.1% of all phylum in the biofilms when bromate served as the sole electron acceptor. Meanwhile, the Bacillus strains became the largest phylotype and represented about 37% of the total bacteria in the biofilm, indicating that the genus Bacillus played the key role in the auto-hydrogenotrophic process. Moreover, three new bacterial genera, Exiguobacterium, Arthrobacter and Chlorobium appeared with the respective relative abundance being about 7.37%, 1.81%, and 0.52%, which might be the bromate-specific reducing bacteria.}, } @article {pmid28825445, year = {2017}, author = {Pumeesat, P and Muangkaew, W and Ampawong, S and Luplertlop, N}, title = {Candida albicans biofilm development under increased temperature.}, journal = {The new microbiologica}, volume = {40}, number = {4}, pages = {279-283}, pmid = {28825445}, issn = {1121-7138}, mesh = {Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*growth & development ; Humans ; Temperature ; }, abstract = {C. albicans is one of the most important species of fungi known to produce biofilms on installed medical devices. The environment surrounding the fungi influences the development of the biofilm. Temperature is known to affect the yeast-to-hypha transition of C. albicans, but the impact of this factor on biofilm formation is still not understood. This study aimed to investigate the effects of temperature (42°C versus 37°C) on the formation of C. albicans biofilms. Three reference C. albicans strains were used: SC 5314, ATCC 90028, and ATCC 96901. Biofilm development was monitored in a series of time intervals, 2, 4, 6, 8, 24, and 48 h, at both 37°C and 42°C. Biofilm formation under each condition was evaluated by scanning electron microscopy, crystal violet staining, and 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-(phenylamino)-carbonyl-2H-tetrazoliumhydroxide reduction assay. Our results demonstrated that at 42°C, tested strains of C. albicans could produce a biofilm, but the mass, thickness, and metabolic activity were lower than those of the biofilm formed at 37°C.}, } @article {pmid28824879, year = {2017}, author = {Chan, CL and Richter, K and Wormald, PJ and Psaltis, AJ and Vreugde, S}, title = {Alloiococcus otitidis Forms Multispecies Biofilm with Haemophilus influenzae: Effects on Antibiotic Susceptibility and Growth in Adverse Conditions.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {344}, pmid = {28824879}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antibiosis/drug effects/physiology ; Biofilms/*growth & development ; Biomass ; Carnobacteriaceae/cytology/*drug effects/growth & development/*physiology ; Coculture Techniques ; Coinfection ; Haemophilus influenzae/cytology/*drug effects/growth & development/*physiology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Otitis Media/microbiology ; Otitis Media with Effusion/*microbiology ; }, abstract = {Otitis media with effusion (OME) is a biofilm driven disease and commonly accepted otopathogens, such as Haemophilus influenzae, Streptococcus pneumonia, and Moraxella catarrhalis, have been demonstrated to form polymicrobial biofilms within the middle ear cleft. However, Alloiococcus otitidis (A. otitidis), which is one of the most commonly found bacteria within middle ear aspirates of children with OME, has not been described to form biofilms. The aim of this study was to investigate whether A. otitidis can form biofilms and investigate the impact on antibiotic susceptibility and survivability in polymicrobial biofilms with H. influenzae in vitro. The ability of A. otitidis to form single-species and polymicrobial biofilms with H. influenzae was explored. Clinical and commercial strains of A. otitidis and H. influenzae were incubated in brain heart infusion with and without supplementation. Biofilm was imaged using confocal laser scanning microscopy and scanning electron microscopy. Quantification of biofilm biomass and viable bacterial number was assessed using crystal violet assays and viable cell counting in both optimal growth conditions and in adverse growth conditions (depleted media and sub-optimal growth temperature). Antimicrobial susceptibility and changes in antibiotic resistance of single-species and multi-species co-culture were assessed using a microdilution method to assess minimal bactericidal concentration and E-test for amoxicillin and ciprofloxacin. A. otitidis formed single-species and polymicrobial biofilms with H. influenzae. Additionally, whilst strain dependent, combinations of polymicrobial biofilms decreased antimicrobial susceptibility, albeit a small magnitude, in both planktonic and polymicrobial biofilms. Moreover, A. otitidis promoted H. influenzae survival by increasing biofilm production in depleted media and at suboptimal growth temperature. Our findings suggest that A. otitidis may play an indirect pathogenic role in otitis media by altering H. influenzae antibiotic susceptibility and enhancing growth under adverse conditions.}, } @article {pmid28823093, year = {2017}, author = {Budzyńska, A and Różalska, S and Sadowska, B and Różalska, B}, title = {Candida albicans/Staphylococcus aureus Dual-Species Biofilm as a Target for the Combination of Essential Oils and Fluconazole or Mupirocin.}, journal = {Mycopathologia}, volume = {182}, number = {11-12}, pages = {989-995}, pmid = {28823093}, issn = {1573-0832}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Clove Oil/pharmacology ; Drug Combinations ; Fluconazole/*pharmacology ; Geranium/chemistry ; Hyphae/growth & development ; Microbial Sensitivity Tests ; Mupirocin/*pharmacology ; Oils, Volatile/*pharmacology ; Plant Oils/pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {The effectiveness of essential oils (EOs), fluconazole (FLU) and mupirocin (MUP) used alone or in combination against mono-species and mixed Candida albicans/Staphylococcus aureus biofilms was examined. An experimentally established dual-species biofilm model, verified by fluorescence microscopy and viable cell counting, was used. Selected commercial EOs were tested: geranium, citronella and clove oils, which have been chemically characterized and found to differ in the content of the main components (qualitative and quantitative). As expected, C. albicans and S. aureus biofilms were less susceptible to fluconazole and mupirocin action, respectively, compared to the planktonic counterparts. However, the drug effectiveness in combination with the EOs was significantly improved, giving enhancement of biofilm eradication than caused by the antibiotics alone. Moreover, dual-species biofilm formation was limited by sub-MIC of EOs, and preformed mixed biofilm was eliminated more efficiently by combined action of drugs and EOs.}, } @article {pmid28823045, year = {2017}, author = {Ruangcharoen, S and Suwannarong, W and Lachica, MRCT and Bolscher, JGM and Nazmi, K and Khunkitti, W and Taweechaisupapong, S}, title = {Killing activity of LFchimera on periodontopathic bacteria and multispecies oral biofilm formation in vitro.}, journal = {World journal of microbiology & biotechnology}, volume = {33}, number = {9}, pages = {167}, pmid = {28823045}, issn = {1573-0972}, mesh = {Aggregatibacter actinomycetemcomitans/drug effects/physiology ; Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Periodontitis/*microbiology ; Plankton/drug effects ; }, abstract = {Lactoferrin chimera (LFchimera), a heterodimeric peptide containing lactoferrampin (LFampin265-284) and a part of lactoferricin (LFcin17-30), possesses a broad spectrum of antimicrobial activity. However, there is no report on the inhibitory effects of LFchimera against multispecies oral biofilms. This study aimed to determine the effects of LFchimera in comparison to chlorhexidine digluconate (CHX) and minocycline hydrochloride (MH), on in vitro multispecies biofilms derived from subgingival plaque of periodontitis patients harboring Aggregatibacter actinomycetemcomitans. First the effects of LFchimera against planktonic and an 1-day old biofilm of the periodontopathic bacteria, A. actinomycetemcomitans ATCC 43718 were established. Then, the effects on biofilm formation and bacterial viability in the multispecies biofilm were determined by crystal violet staining and LIVE/DEAD BacLight Bacterial Viability kit, respectively. The results revealed that a significant reduction (P < 0.05) in biofilm formation occurred after 15 min exposure to 20 µM of LFchimera or CHX compared to control. In contrast, MH at concentration up to 100 µM did not inhibit biofilm formation. The ratio of live/dead bacteria in biofilm was also significantly lower after 15 min exposure to 20 µM of LFchimera compared to control and 20-50 µM of CHX and MH. Altogether, the results obtained indicate that LFchimera is able to inhibit in vitro subgingival biofilm formation and reduce viability of multispecies bacteria in biofilm better than CHX and MH.}, } @article {pmid28822938, year = {2018}, author = {Crampon, M and Hellal, J and Mouvet, C and Wille, G and Michel, C and Wiener, A and Braun, J and Ollivier, P}, title = {Do natural biofilm impact nZVI mobility and interactions with porous media? A column study.}, journal = {The Science of the total environment}, volume = {610-611}, number = {}, pages = {709-719}, doi = {10.1016/j.scitotenv.2017.08.106}, pmid = {28822938}, issn = {1879-1026}, mesh = {*Biofilms ; Groundwater/*chemistry ; Iron/*chemistry ; Metal Nanoparticles/*chemistry ; Porosity ; Pseudomonas stutzeri ; }, abstract = {Nanoparticles (NP) used as remediation agents for groundwater treatment may interact with biofilms naturally present, altering NP mobility and/or reactivity and thereby NP effectiveness. The influence of the presence of a multi species biofilm on the mobility of two types of zero-valent iron NP (nZVI; NANOFER 25S and optimized NANOFER STAR, NanoIron s.r.o. (Czech Republic)) was tested in laboratory experiments with columns mimicking aquifer conditions. Biofilms were grown in columns filled with sand in nitrate reducing conditions using groundwater from an industrial site as inoculum. After two months growth, they were composed of several bacterial species, dominated by Pseudomonas stutzeri. Biofilm strongly affected the physical characteristics of the sand, decreasing total porosity from ~30% to ~15%, and creating preferential pathways with high flow velocities. nZVI suspensions were injected into the columns at a seepage velocity of 10mday[-][1]. Presence of biofilm did not impact the concentrations of Fe at the column outlet nor the amount of total Fe retained in the sand, as attested by the measurement of magnetic susceptibility. However, it had a significant impact on NP size sorting as well as on total Fe distribution along the column. This suggests nZVI-biofilm interactions that were confirmed by microscopic observations using SEM/STEM coupled with energy-dispersive X-ray spectroscopy. Our study shows that biofilm modifies the water flow velocity in the porous media, favoring the transport of large aggregates and decreased NP mobility due to physical and chemical interactions.}, } @article {pmid28821865, year = {2017}, author = {Sonesson, A and Przybyszewska, K and Eriksson, S and Mörgelin, M and Kjellström, S and Davies, J and Potempa, J and Schmidtchen, A}, title = {Identification of bacterial biofilm and the Staphylococcus aureus derived protease, staphopain, on the skin surface of patients with atopic dermatitis.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {8689}, pmid = {28821865}, issn = {2045-2322}, mesh = {Adult ; Amino Acid Sequence ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides ; Biofilms/*drug effects ; Cathelicidins/pharmacology ; Cysteine Endopeptidases/*pharmacology ; Dermatitis, Atopic/*microbiology ; Humans ; Microbial Sensitivity Tests ; Peptide Fragments/chemistry/pharmacology ; Skin/*microbiology/pathology ; Staphylococcus aureus/drug effects/*physiology/ultrastructure ; }, abstract = {Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by an impaired epidermal barrier, dysregulation of innate and adaptive immunity, and a high susceptibility to bacterial colonization and infection. In the present study, bacterial biofilm was visualized by electron microscopy at the surface of AD skin. Correspondingly, Staphylococcus aureus (S. aureus) isolates from lesional skin of patients with AD, produced a substantial amount of biofilm in vitro. S. aureus biofilms showed less susceptibility to killing by the antimicrobial peptide LL-37 when compared with results obtained using planktonic cells. Confocal microscopy analysis showed that LL-37 binds to the S. aureus biofilms. Immuno-gold staining of S. aureus biofilm of AD skin detected the S. aureus derived protease staphopain adjacent to the bacteria. In vitro, staphopain B degraded LL-37 into shorter peptide fragments. Further, LL-37 significantly inhibited S. aureus biofilm formation, but no such effects were observed for the degradation products. The data presented here provide novel information on staphopains present in S. aureus biofilms in vivo, and illustrate the complex interplay between biofilm and LL-37 in skin of AD patients, possibly leading to a disturbed host defense, which facilitates bacterial persistence.}, } @article {pmid28821458, year = {2017}, author = {Fteita, D and Musrati, AA and Könönen, E and Ma, X and Gürsoy, M and Peurla, M and Söderling, E and Sintim, HO and Gürsoy, UK}, title = {Dipeptidyl peptidase IV and quorum sensing signaling in biofilm-related virulence of Prevotella aurantiaca.}, journal = {Anaerobe}, volume = {48}, number = {}, pages = {152-159}, doi = {10.1016/j.anaerobe.2017.08.009}, pmid = {28821458}, issn = {1095-8274}, mesh = {Bacteroidaceae Infections/*microbiology ; Biofilms/drug effects/*growth & development ; Dipeptidyl Peptidase 4/*metabolism ; Enzyme Activation ; Estradiol/pharmacology ; Humans ; Microbial Viability/drug effects ; Prevotella/pathogenicity/*physiology/ultrastructure ; *Quorum Sensing ; *Signal Transduction ; Virulence ; Virulence Factors ; }, abstract = {Biofilm formation and dipeptidyl peptidase IV (DPPIV) enzyme activity contribute to the virulence of oral bacteria, and these virulence factors are partly regulated by quorum sensing signaling system. We recently demonstrated that estradiol regulates growth properties and DPPIV activity of Prevotella intermedia, Prevotella nigrescens, and Prevotella pallens. Here, we examined the DPPIV dependency of biofilm formation of Prevotella aurantiaca. Three strains (two clinical strains AHN 37505 and 37552 and the type strain CCUG 57723) were incubated in three estradiol concentrations (30, 90, and 120 nmol/L). Regulation of DPPIV activity, biofilm and fimbria formation, and coaggregation of bacterial strains were analyzed after incubation with four concentrations (10 nM, 100 nM, 1 μM, 10 μM) of dihydroxy-2,3-pentaedione (DPD), the universal precursor of autoinducer -2 (AI-2), and analogs (ethyl-DPD, butyl-DPD, and isobutyl-DPD) for 24 h. Estradiol enhanced the planktonic growth, coaggregation, and biofilm formation of P. aurantiaca strains. The whole cell extract of AHN 37505 had the highest DPPIV activity, followed by CCUG 57723 and AHN 37552. Inhibition of DPPIV activity with di-isopropylfluorophosphate suppressed the effect of estradiol on biofilm formation. At 100 nM and 10 μM concentrations of DPD, butyl DPD, and isobutyl DPD, biofilm formation of P. aurantiaca was significantly inhibited. Fimbriae formation was enhanced up to concentrations of 100 nM and 1 μM followed by a significant inhibition at higher concentrations of DPD and all analogs. A slight but significant inhibitory effect of DPD and analogs on DPPIV activity was observed. Our results indicate that DPPIV plays a key role in the estradiol-regulated biofilm formation of P. aurantiaca. Quorum sensing autoinducer DPD and C1-alkyl analogs could inhibit biofilm-related virulence of P. aurantiaca.}, } @article {pmid28821225, year = {2017}, author = {Xu, X and Tong, T and Yang, X and Pan, Y and Lin, L and Li, C}, title = {Differences in survival, virulence and biofilm formation between sialidase-deficient and W83 wild-type Porphyromonas gingivalis strains under stressful environmental conditions.}, journal = {BMC microbiology}, volume = {17}, number = {1}, pages = {178}, pmid = {28821225}, issn = {1471-2180}, mesh = {Adaptation, Biological/physiology ; Adhesins, Bacterial/metabolism ; Biofilms/*growth & development ; Cysteine Endopeptidases/metabolism ; Genes, Bacterial ; Gingipain Cysteine Endopeptidases ; Hydrogen Peroxide/antagonists & inhibitors ; Hydrogen-Ion Concentration ; Lipopolysaccharides/pharmacology ; Microbial Viability/drug effects/genetics ; Microscopy, Electron, Transmission ; Mutation ; Neuraminidase/genetics/*physiology ; Oxidative Stress ; Porphyromonas gingivalis/drug effects/genetics/*physiology ; *Stress, Physiological ; Temperature ; *Virulence/genetics ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Porphyromonas gingivalis is a major causative pathogen of chronic periodontitis. Within the inflammatory microenvironment, there exists extreme pH values, elevated temperatures and oxidative stress. Pathogens adapt to these stressful environmental conditions by regulating the transcription of virulence genes, modifying themselves with macromolecules and by aggregating and entering into a biofilm growth phase. Our previous study showed that the P. gingivalis sialidase can help cells obtain sialic acid from the environment, which is used to modify macromolecules on the surface of P. gingivalis cells. In this study, we compared the survival, virulence factors and biofilm formation of a sialidase-deficient strain (ΔPG0352) and the wild-type P. gingivalis W83 strain under various pH values, temperatures and oxidative stress conditions to identify the roles of sialidase in the adaptation of P. gingivalis to stressful conditions.

RESULTS: Compared to the growth of the P. gingivalis W83 strain, the growth of the △PG0352 was more inhibited by oxidative stress (0.25 and 0.5 mM H2O2) and exhibited greater cell structure damage when treated with H2O2 as assessed by transmission electron microscopy. Both Lys-gingipain (Kgp) and Arg-gingipain (Rgp) activities were lower in the ΔPG0352 than those in the P. gingivalis W83 strain under all the assayed culture conditions. The lipopolysaccharide (LPS) activity of the W83 strain was higher than that of the ΔPG0352 under acidic conditions (pH 5.0), but no differences between the strains were observed under other conditions. Compared to the biofilms formed by P. gingivalis W83, those formed by the ΔPG0352 were decreased and discontinuous under acidic, alkaline and oxidative stress conditions.

CONCLUSION: Compared to the P. gingivalis W83 strain, the survival, virulence and biofilm formation of the ΔPG0352 were decreased under stressful environmental conditions.}, } @article {pmid28819217, year = {2017}, author = {Li, XH and Kim, SK and Lee, JH}, title = {Anti-biofilm effects of anthranilate on a broad range of bacteria.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {8604}, pmid = {28819217}, issn = {2045-2322}, mesh = {Bacteria/*drug effects ; Biofilms/*drug effects ; Cyclic GMP/analogs & derivatives/metabolism ; Hep G2 Cells ; Humans ; Microbial Sensitivity Tests ; Movement ; Tryptophan/pharmacology ; ortho-Aminobenzoates/*pharmacology ; }, abstract = {Anthranilate, one of tryptophan degradation products has been reported to interfere with biofilm formation by Pseudomonas aeruginosa. Here, we investigated the effects of anthranilate on biofilm formation by various bacteria and the mechanisms responsible. Anthranilate commonly inhibited biofilm formation by P. aeruginosa, Vibrio vulnificus, Bacillus subtilis, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus, and disrupted biofilms preformed by these bacteria. Because anthranilate reduced intracellular c-di-GMP and enhanced swimming and swarming motilities in P. aeruginosa, V. vulnificus, B. subtilis, and S. enterica, it is likely that anthranilate disrupts biofilms by inducing the dispersion of these bacteria. On the other hand, in S. aureus, a non-flagellate bacterium that has no c-di-GMP signaling, anthranilate probably inhibits biofilm formation by reducing slime production. These results suggest that anthranilate has multiple ways for biofilm inhibition. Furthermore, because of its good biofilm inhibitory effects and lack of cytotoxicity to human cells even at high concentration, anthranilate appears to be a promising agent for inhibiting biofilm formation by a broad range of bacteria.}, } @article {pmid28818902, year = {2017}, author = {Braun, B and Künzel, S and Szewzyk, U}, title = {Draft Genome Sequence of Ideonella sp. Strain A 288, Isolated from an Iron-Precipitating Biofilm.}, journal = {Genome announcements}, volume = {5}, number = {33}, pages = {}, pmid = {28818902}, issn = {2169-8287}, abstract = {Here, we report the draft genome sequence of the betaproteobacterium Ideonella sp. strain A_228. This isolate, obtained from a bog iron ore-containing floodplain area in Germany, provides valuable information about the genetic diversity of neutrophilic iron-depositing bacteria. The Illumina NextSeq technique was used to sequence the draft genome sequence of the strain.}, } @article {pmid28818490, year = {2017}, author = {Kalaiarasan, E and Thirumalaswamy, K and Harish, BN and Gnanasambandam, V and Sali, VK and John, J}, title = {Inhibition of quorum sensing-controlled biofilm formation in Pseudomonas aeruginosa by quorum-sensing inhibitors.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {99-107}, doi = {10.1016/j.micpath.2017.08.017}, pmid = {28818490}, issn = {1096-1208}, mesh = {4-Butyrolactone/analogs & derivatives/chemistry/pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Down-Regulation ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; Leukocytes, Mononuclear/drug effects ; Models, Molecular ; Molecular Docking Simulation ; Pseudomonas aeruginosa/*drug effects/genetics/growth & development/physiology ; Quorum Sensing/*drug effects/genetics ; Trans-Activators/genetics/metabolism ; Virulence Factors/genetics ; }, abstract = {Antimicrobial therapy against extensively drug-resistant (XDR) P. aeruginosa biofilms is less efficient compared to the treatment of equal bacterial counts of free-floating planktonic cells, which has become a serious threat in hospital environment. P. aeruginosa regulate their cooperative activities and physiological processes through a cell to cell chemical communication process called Quorum sensing (QS). This attracted our interest to synthesize, and to chemically characterize two anti-QS compounds, N-(4-{4-fluoroanilno} butanoyl) -l-homoserine lactone (FABHL) and N-(4-{4-chlororoanilno} butanoyl) -l-homoserine lactone (CABHL) to inhibit biofilm formation via disabling the QS circuits. Structural and morphological properties of these compounds were characterized by [1]H Nuclear Magnetic Resonance (NMR), [13]C NMR and High-resolution mass spectrometry (HRMS). Two biofilm forming XDR P. aeruginosa isolates were included in this study. Anti-biofilm property of FABHL or CABHL was confirmed by biofilm formation assay and it was shown to occur without affecting the bacterial growth. Anti-QS property of FABHL or CABHL was determined by evaluating the expression levels of QS genes (lasR and rhlR) by quantitative real time PCR (qRT-PCR). Although, FABHL and CABHL downregulates the expression levels of QS genes, lasR expression was significantly reduced. Molecular modeling studies revealed that the binding energy of FABHL and CABHL with LasR protein was -4.27 and -4.51, respectively. Hence, the synthesized compounds have the potential to serve as a potent anti-biofilm agent via disabling the QS systems. Lethality of FABHL and CABHL against PBMCs was assessed by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphynyl tetrazolium bromide (MTT) assay. Cell viability was observed for both the compounds.}, } @article {pmid28818264, year = {2017}, author = {Chanda, W and Joseph, TP and Wang, W and Padhiar, AA and Zhong, M}, title = {The potential management of oral candidiasis using anti-biofilm therapies.}, journal = {Medical hypotheses}, volume = {106}, number = {}, pages = {15-18}, doi = {10.1016/j.mehy.2017.06.029}, pmid = {28818264}, issn = {1532-2777}, mesh = {Antifungal Agents/therapeutic use ; Biofilms/drug effects/growth & development ; Candida albicans/drug effects/growth & development/immunology ; Candidiasis, Oral/immunology/microbiology/*therapy ; Host-Pathogen Interactions/drug effects/immunology ; Humans ; Immunoglobulin A/biosynthesis ; Lactoferrin/therapeutic use ; Microbiota/drug effects/immunology ; Models, Biological ; Photochemotherapy ; Probiotics/therapeutic use ; Saliva/immunology/microbiology ; Streptococcus mutans/growth & development/immunology ; }, abstract = {Candida albicans is a minor component of the oral microbiota and an opportunistic pathogen that takes advantage of the immunocompromised host and causes oral mucositis and oral candidiasis. This organism is able to undergo phenotypic modification from a yeast to hyphae growth phase, one of the key arsenals for immune cell evasion, tissue invasion and biofilm formation. The latter property coupled with overgrowth and immune compromising factors such as HIV/AIDS, cancer treatments, organ transplantation, diabetes, corticosteroid use, dentures, and broad-spectrum antibiotic use have modified the fungus from a normal component of the microflora to a foe of an oral cavity and resulting in reduced sensitivity towards commonly utilised antifungal agents. Hence, the need for alternative therapy to curb this plight is of importance. Making use of biomolecules produced by Streptococcus mutans, application of lactoferrin which is a nonspecific host defense factor found in saliva with metal chelating and broader antimicrobial properties, use of probiotics which have the capacity to boost the host immunity through eliciting Immunoglobulin A synthesis, and perturbing the pathogen's environment via competition of space and food, and application of photodynamic therapy can help to manage the burden of oral candidiasis.}, } @article {pmid28816070, year = {2018}, author = {}, title = {Correction to: Rossi E, et al., "It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment.}, journal = {Critical reviews in microbiology}, volume = {44}, number = {1}, pages = {i}, doi = {10.1080/1040841X.2017.1364539}, pmid = {28816070}, issn = {1549-7828}, } @article {pmid28815023, year = {2017}, author = {Różańska, A and Chmielarczyk, A and Romaniszyn, D and Bulanda, M and Walkowicz, M and Osuch, P and Knych, T}, title = {Antibiotic resistance, ability to form biofilm and susceptibility to copper alloys of selected staphylococcal strains isolated from touch surfaces in Polish hospital wards.}, journal = {Antimicrobial resistance and infection control}, volume = {6}, number = {}, pages = {80}, pmid = {28815023}, issn = {2047-2994}, abstract = {BACKGROUND: Despite the employment of sanitary regimes, contact transmission of the aetiological agents of hospital infections is still exceedingly common. The issue of microbe transmission becomes particularly important when facing multidrug-resistant microorganisms such as methicillin-resistant staphylococci. In the case of deficiencies in cleaning and disinfection procedures, hospital equipment made of copper alloys can play an important role, complementing traditional hospital hygiene procedures. The objective of this study was to characterize staphylococcal strains isolated from touch surfaces in Polish hospital wards in terms of their drug resistance, ability to form biofilm and susceptibility to antimicrobial activity of copper alloys.

METHODS: The materials for the study were 95 staphylococcal strains isolated from touch surfaces in 13 different hospital wards from Małopolska province (the south of Poland). Phenotypic and genotypic antibiotic resistance were checked for erythromycin, clindamycin, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole and mupirocin. Biofilm formation ability for the tested strains was checked with the use of culture on Congo red agar. Susceptibility to copper, tin bronze, brass and new silver was tested using a modification of the Japanese standard.

RESULTS: Over 67% of the analysed staphylococcal strains were methicillin-resistant (MR). Four strains were resistant to all of the tested antibiotics, and 14 were resistant to all except mupirocin. Strains classified as MR had significantly increased resistance to the remaining antibiotic groups. About one-third of the analysed strains revealed biofilm-forming ability. Among the majority of species, biofilm-forming and non-biofilm-forming strains were distributed evenly; in the case of S. haemolyticus only, negative strains accounted for 92.8%. Susceptibility to copper alloys was different between strains and rather lower than in the case of the SA strain selected for comparison.

CONCLUSIONS: Coagulase-negative staphylococci, the most commonly isolated in Polish hospital wards, should not be neglected as an infection risk factor due their high antibiotic resistance. Our experiments confirmed that touch surfaces made of copper alloys may play an important role in eliminating bacteria from the hospital environment.}, } @article {pmid28813499, year = {2017}, author = {Peng, KT and Hsieh, CC and Huang, TY and Chen, PC and Shih, HN and Lee, MS and Chang, PJ}, title = {Staphylococcus aureus biofilm elicits the expansion, activation and polarization of myeloid-derived suppressor cells in vivo and in vitro.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0183271}, pmid = {28813499}, issn = {1932-6203}, mesh = {Animals ; Biofilms/*growth & development ; Cells, Cultured ; Flow Cytometry ; Macrophages/metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Myeloid Cells/*cytology ; Rats ; Reverse Transcriptase Polymerase Chain Reaction ; Staphylococcus aureus/*physiology ; T-Lymphocytes/metabolism ; T-Lymphocytes, Regulatory/metabolism ; }, abstract = {Staphylococcus aureus (S. aureus) is one of the most common causes of biofilm infections in periprosthetic joint infections (PJIs). Accumulating evidence has shown that the immunosuppressive environment established by S. aureus biofilm infection in PJIs involves the presence of myeloid-derived suppressor cells (MDSCs) and M2-macrophages. Due to the diversity of MDSCs, little is known about whether S. aureus biofilm preferentially expands specific MDSC subsets or whether MDSCs can further differentiate into M2-macrophages during S. aureus biofilm infection. Here, we show that in agreement with the results from an established rat PJI model, S. aureus biofilm cocultured with freshly isolated bone marrow cells (BMCs) in vitro significantly increases the proportions of MDSCs, total macrophages and M2-macrophages. Interestingly, we find that treatment of the BMCs in vitro with S. aureus biofilm preferentially promotes the expansion of monocytic MDSCs but not granulocytic MDSCs. Biofilm treatment also substantially enhances the overall MDSC immunosuppressive activity in addition to the MDSC expansion in vitro. Importantly, we provide evidence that S. aureus biofilm is capable of further stimulating the conversion of monocytic MDSCs into M2-macrophages in vitro and in vivo. Collectively, our studies reveal a direct link between MDSCs and M2-macrophages occurring in S. aureus-associated PJIs.}, } @article {pmid28812881, year = {2017}, author = {Lesnik, KL and Liu, H}, title = {Predicting Microbial Fuel Cell Biofilm Communities and Bioreactor Performance using Artificial Neural Networks.}, journal = {Environmental science & technology}, volume = {51}, number = {18}, pages = {10881-10892}, doi = {10.1021/acs.est.7b01413}, pmid = {28812881}, issn = {1520-5851}, mesh = {Bioelectric Energy Sources ; *Biofilms ; *Bioreactors ; *Neural Networks, Computer ; *Wastewater ; }, abstract = {The complex interactions that occur in mixed-species bioelectrochemical reactors, like microbial fuel cells (MFCs), make accurate predictions of performance outcomes under untested conditions difficult. While direct correlations between any individual waste stream characteristic or microbial community structure and reactor performance have not been able to be directly established, the increase in sequencing data and readily available computational power enables the development of alternate approaches. In the current study, 33 MFCs were evaluated under a range of conditions including eight separate substrates and three different wastewaters. Artificial Neural Networks (ANNs) were used to establish mathematical relationships between wastewater/solution characteristics, biofilm communities, and reactor performance. ANN models that incorporated biotic interactions predicted reactor performance outcomes more accurately than those that did not. The average percent error of power density predictions was 16.01 ± 4.35%, while the average percent error of Coulombic efficiency and COD removal rate predictions were 1.77 ± 0.57% and 4.07 ± 1.06%, respectively. Predictions of power density improved to within 5.76 ± 3.16% percent error through classifying taxonomic data at the family versus class level. Results suggest that the microbial communities and performance of bioelectrochemical systems can be accurately predicted using data-mining, machine-learning techniques.}, } @article {pmid28810631, year = {2017}, author = {Sun, Y and Sun, F and Feng, W and Qiu, X and Liu, Y and Yang, B and Chen, Y and Xia, P}, title = {Hyperoside inhibits biofilm formation of Pseudomonas aeruginosa.}, journal = {Experimental and therapeutic medicine}, volume = {14}, number = {2}, pages = {1647-1652}, pmid = {28810631}, issn = {1792-0981}, abstract = {Pseudomonas aeruginosa (P. aeruginosa) is a common pathogen in hospital-acquired infection and is readily able to form biofilms. Due to its high antibiotic resistance, traditional antibacterial treatments exert a limited effect on P. aeruginosa biofilm infections. It has been indicated that hyperoside inhibits P. aeruginosa PAO1 (PAO1) biofilm formation without affecting growth. Therefore, the current study examined the biofilm formation and quorum sensing (QS) system of PAO1 in the presence of hyperoside. Confocal laser scanning microscopy analysis demonstrated that hyperoside significantly inhibited biofilm formation. It was also observed that hyperoside inhibited twitching motility in addition to adhesion. Data from reverse transcription-quantitative polymerase chain reaction indicated that hyperoside inhibited the expression of lasR, lasI, rhlR and rhlI genes. These results suggest that the QS-inhibiting effect of hyperoside may lead to a reduction in biofilm formation. However, the precise mechanism of hyperoside on P. aeruginosa pathogenicity remains unclear and requires elucidation in additional studies.}, } @article {pmid28810610, year = {2017}, author = {Pan, Y and Du, L and Ai, Q and Song, S and Tang, X and Zhu, D and Yu, J}, title = {Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia.}, journal = {Experimental and therapeutic medicine}, volume = {14}, number = {2}, pages = {1450-1458}, pmid = {28810610}, issn = {1792-0981}, abstract = {Ventilator-associated pneumonia (VAP) is a common nosocomial infection in neonatal intensive care units with high morbidity and mortality. Bacterial biofilm in the endotracheal tube (ET) provides a notable and persistent source of pathogens that may cause VAP, and thus is important for VAP detection. However, during intubation microbial investigations in ET, samples are unavailable due to the infeasibility of collecting ET samples during intubation of neonates. It is therefore of great importance to find alternative sources of samples that can help identify the ET biofilm flora. In the present study, the microbial signatures of throat swabs and tracheal aspirates were compared with ET biofilm samples from VAP neonates using 16S ribosomal RNA gene polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. Sequences were assigned to phylogenetic species using BLAST. Microbial diversity and richness among the three types of specimens were compared based on their DGGE fingerprints, and taxonomic characteristics based on the BLAST results. The microbial richness and diversity of ET biofilms were similar to tracheal aspirate yet significantly different from throat swab samples (P<0.05). Compared with ET biofilms, the overall constituent ratio of microflora was significantly different in throat swab and tracheal aspirate samples (P<0.05). However tracheal aspirate samples were useful for predicting Staphylococcus sp. in ET biofilms with a sensitivity of 85.7% and a specificity of 83.3%. The sensitivity for the combination of tracheal aspirate and throat swab samples to detect Staphylococcus sp. in ET biofilms was 100%. The detection of Pseudomonas sp. in throat swabs assisted its identification in ET biofilms (sensitivity 33.3% and specificity 100%). The results of the present study suggest that microbial investigations in throat swab and tracheal aspirate samples are beneficial for identifying the ET biofilm flora. There may therefore be clinical applications of using substituent samples to identify pathogens in ET biofilms for VAP surveillance among intubated neonates.}, } @article {pmid28808327, year = {2017}, author = {Lim, JH and Song, SH and Park, HS and Lee, JR and Lee, SM}, title = {Spontaneous detachment of Streptococcus mutans biofilm by synergistic effect between zwitterion and sugar alcohol.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {8107}, pmid = {28808327}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects ; Streptococcus mutans/*drug effects ; Sugar Alcohols/*pharmacology ; }, abstract = {A biofilm, a community of microorganisms, is highly resistant to antibiotics, resulting in massive losses in various areas. We herein present a strategy to remove Streptococcus mutans biofilms through a spontaneous exfoliation by the synergistic effect between zwitterion and sugar alcohols. It is assumed that the anionic site of zwitterion can be coupled with sugar alcohols and the cationic site remains in the state of lacking electrons. The cationic site allows the complexes to be delivered to negatively charged exopolysaccharides of biofilms. This strategy facilitates a significant increase in the ability of sugar alcohols to disperse aggregated exopolysaccharides. In this work, it was demonstrated that the mixture of betaine and erythritol existed as a complex in water and that the complex induced a spontaneous detachment of biofilms from the surface to which the biofilms had been adhered. This detachment resulted from a reduction in adhesive forces of the biofilms due to an increase in solubility of bacterial exopolysaccharides. The effects triggered by the formation of complex between zwitterion and sugar alcohol provide a simple and safe way to remove biofilms without antibiotics and physical forces.}, } @article {pmid28806528, year = {2017}, author = {Hu, D and Li, H and Wang, B and Ye, Z and Lei, W and Jia, F and Jin, Q and Ren, KF and Ji, J}, title = {Surface-Adaptive Gold Nanoparticles with Effective Adherence and Enhanced Photothermal Ablation of Methicillin-Resistant Staphylococcus aureus Biofilm.}, journal = {ACS nano}, volume = {11}, number = {9}, pages = {9330-9339}, doi = {10.1021/acsnano.7b04731}, pmid = {28806528}, issn = {1936-086X}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology/*therapeutic use ; Biofilms/*drug effects/radiation effects ; Delayed-Action Preparations/chemistry ; Gold/chemistry/pharmacology/*therapeutic use ; Humans ; Hydrogen-Ion Concentration ; Hyperthermia, Induced/methods ; Infrared Rays ; Metal Nanoparticles/chemistry/*therapeutic use ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology/radiation effects ; Rabbits ; Staphylococcal Infections/*therapy ; }, abstract = {Biofilms that contribute to the persistent bacterial infections pose serious threats to global public health, mainly due to their resistance to antibiotics penetration and escaping innate immune attacks by phagocytes. Here, we report a kind of surface-adaptive gold nanoparticles (AuNPs) exhibiting (1) a self-adaptive target to the acidic microenvironment of biofilm, (2) an enhanced photothermal ablation of methicillin-resistant Staphylococcus aureus (MRSA) biofilm under near-infrared (NIR) light irradiation, and (3) no damage to the healthy tissues around the biofilm. Originally, AuNPs were readily prepared by surface modification with pH-responsive mixed charged zwitterionic self-assembled monolayers consisting of weak electrolytic 11-mercaptoundecanoic acid (HS-C10-COOH) and strong electrolytic (10-mercaptodecyl)trimethylammonium bromide (HS-C10-N4). The mixed charged zwitterion-modified AuNPs showed fast pH-responsive transition from negative charge to positive charge, which enabled the AuNPs to disperse well in healthy tissues (pH ∼7.4), while quickly presenting strong adherence to negatively charged bacteria surfaces in MRSA biofilm (pH ∼5.5). Simultaneous AuNP aggregation within the MRSA biofilm enhanced the photothermal ablation of MRSA biofilm under NIR light irradiation. The surrounding healthy tissues showed no damage because the dispersed AuNPs had no photothermal effect under NIR light. In view of the above advantages as well as the straightforward preparation, AuNPs developed in this work may find potential applications as a useful antibacterial agent in the areas of healthcare.}, } @article {pmid28805046, year = {2017}, author = {Gomez-Carretero, S and Nybom, R and Richter-Dahlfors, A}, title = {Electroenhanced Antimicrobial Coating Based on Conjugated Polymers with Covalently Coupled Silver Nanoparticles Prevents Staphylococcus aureus Biofilm Formation.}, journal = {Advanced healthcare materials}, volume = {6}, number = {20}, pages = {}, doi = {10.1002/adhm.201700435}, pmid = {28805046}, issn = {2192-2659}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry/pharmacology ; Electrochemical Techniques ; Electrodes ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Polymers/*chemistry ; Polystyrenes/chemistry ; Silver/*chemistry ; Staphylococcus aureus/*physiology ; Surface Plasmon Resonance ; Surface Properties ; Thiophenes/chemistry ; Tin Compounds/chemistry ; }, abstract = {The incidence of hospital-acquired infections is to a large extent due to device-associated infections. Bacterial attachment and biofilm formation on surfaces of medical devices often act as seeding points of infection. To prevent such infections, coatings based on silver nanoparticles (AgNPs) are often applied, however with varying clinical success. Here, the traditional AgNP-based antibacterial technology is reimagined, now forming the base for an electroenhanced antimicrobial coating. To integrate AgNPs in an electrically conducting polymer layer, a simple, yet effective chemical strategy based on poly(hydroxymethyl 3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT-MeOH:PSS) and (3-aminopropyl)triethoxysilane is designed. The resultant PEDOT-MeOH:PSS-AgNP composite presents a consistent coating of covalently linked AgNPs, as shown by scanning electron microscopy and surface plasmon resonance analysis. The efficacy of the coatings, with and without electrical addressing, is then tested against Staphylococcus aureus, a major colonizer of medical implants. Using custom-designed culturing devices, a nearly complete prevention of biofilm growth is obtained in AgNP composite devices addressed with a square wave voltage input. It is concluded that this electroenhancement of the bactericidal effect of the coupled AgNPs offers a novel, efficient solution against biofilm colonization of medical implants.}, } @article {pmid28804616, year = {2017}, author = {Shakerimoghaddam, A and Ghaemi, EA and Jamalli, A}, title = {Zinc oxide nanoparticle reduced biofilm formation and antigen 43 expressions in uropathogenic Escherichiacoli.}, journal = {Iranian journal of basic medical sciences}, volume = {20}, number = {4}, pages = {451-456}, pmid = {28804616}, issn = {2008-3866}, abstract = {OBJECTIVES: This study aimed to investigate the effect of zinc oxide nanoparticles (ZnO-np) on biofilm formation and expression of the flu gene in uropathogenic Escherichia coli (UPEC) strains.

MATERIALS AND METHODS: Minimum inhibitory concentration (MIC) of ZnO-np was determined by agar dilution method. The effect of MIC and sub-MIC concentrations of ZnO-np on biofilm formation were determined by microtiter plate assay. The expression level of the flu gene was assessed by Real-Time PCR assay.

RESULTS: MIC and sub-MIC ZnO-np concentrations reduced biofilm formation by 50% and 33.4%, respectively. Sub-MIC ZnO-np concentration significantly reduced the flu gene expression in the UPEC isolates (P<0.0001).

CONCLUSION: The sub-MIC concentration of ZnO-np reduces biofilm formation and flu gene expression in UPEC isolates. It is suggested to use nanoparticles for coating medical devices to prevent bacterial colonization.}, } @article {pmid28804019, year = {2017}, author = {Singh, PK and Yadav, VK and Kalia, M and Dohare, S and Sharma, D and Agarwal, V}, title = {Pseudomonas aeruginosa auto inducer3-oxo-C12-HSL exerts bacteriostatic effect and inhibits Staphylococcus epidermidis biofilm.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {612-619}, doi = {10.1016/j.micpath.2017.08.009}, pmid = {28804019}, issn = {1096-1208}, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; *Antibiosis ; Biofilms/*drug effects/*growth & development ; Homoserine/*analogs & derivatives/metabolism ; Pseudomonas aeruginosa/*metabolism ; Staphylococcus epidermidis/*drug effects/growth & development/*physiology ; }, abstract = {Pseudomonas aeruginosa has evolved the 3-oxo-C12-HSL and C4-HSL based quorum sensing system which is responsible for the regulation of various virulence factors and helps to dominates over other bacterial species. Staphylococcus epidermidis has frequently been reported with P. aeruginosa while the role of C4-HSL and 3-oxo-C12-HSL on the S. epidermidis had widely been unexplored, and as per our knowledge, this is the first report on the impact of C4-HSL and 3-oxo-C12-HSL overS. epidermidis growth and biofilm. We found that among the two AHL molecules; only 3-oxo-C12-HSL was able to exert a significant effect in all the experiments including growth and biofilm of S. epidermidis. 3-oxo-C12-HSL at 100 μM and 200 μM concentrations were able to initiate the apparent transient type of planktonic growth inhibition in S. epidermidis. Microscopic analysis and biofilm quantification assay showed the inhibitory effect of 3-oxo-C12-HSL against S. epidermidis biofilm, initial attachment, and EPS production. The study concludes that P. aeruginosa associated 3-oxo-C12-HSL exerts the inhibitory effect on S. epidermidis growth and biofilms and thus it may also help Pseudomonasto dominate under the co-infection conditions.}, } @article {pmid28804018, year = {2017}, author = {Bonez, PC and Rossi, GG and Bandeira, JR and Ramos, AP and Mizdal, CR and Agertt, VA and Dalla Nora, ESS and de Souza, ME and Dos Santos Alves, CF and Dos Santos, FS and Gündel, A and de Almeida Vaucher, R and Santos, RCV and de Campos, MMA}, title = {Anti-biofilm activity of A22 ((S-3,4-dichlorobenzyl) isothiourea hydrochloride) against Pseudomonas aeruginosa: Influence on biofilm formation, motility and bioadhesion.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {6-13}, doi = {10.1016/j.micpath.2017.08.008}, pmid = {28804018}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Bacterial Proteins/drug effects ; Biofilms/*drug effects/growth & development ; Cell Movement/*drug effects ; Cell Wall ; HeLa Cells ; Humans ; Microbial Sensitivity Tests ; Microscopy, Atomic Force ; Polyethylene ; Pseudomonas aeruginosa/*drug effects ; Thiourea/*analogs & derivatives/antagonists & inhibitors ; Time Factors ; }, abstract = {Bacterial biofilms are involved in various medical infections and for this reason it is of great importance understanding adhesion mechanisms of involved microorganisms is essential to develop new strategies of prevention and control. Different approaches have been used for preventing biofilm related infections in health care settings, such as use of surface coatings agents in medical implants. In this context, is necessary to explore new compounds with anti-biofilm activity. Thus, this study evaluated for the first time the action of A22 against biofilms of Pseudomonas aeruginosa PAO1 strain and multi-resistant clinical isolates on biotic and abiotic surfaces. A22 acts as inhibitor of the MreB protein of the bacterial cell wall, causing the rods to change shape to the coccoid form. In this work, A22 at subinhibitory concentrations was able to prevent biofilm formation, and atomic force microscopy images showed that A22 was highly effective in inhibiting adhesion on polyethylene surfaces. Pseudomonas aeruginosa PAO1 exhibited a strong ability to adhere to HeLa cells, and A22 inhibited the aggregation after 4 h of exposure. Swarming and twitching motilities were significantly altered by A22 at subinhibitory concentrations. Thus, by changing the shape of the bacterial cell, many properties can be affected, such as motility, surface adhesion and biofilm formation. This work presents A22 as a promising novel antibacterial or surface coating agent of medical materials.}, } @article {pmid28803003, year = {2017}, author = {Lin, S and Yang, L and Chen, G and Li, B and Chen, D and Li, L and Xu, Z}, title = {Pathogenic features and characteristics of food borne pathogens biofilm: Biomass, viability and matrix.}, journal = {Microbial pathogenesis}, volume = {111}, number = {}, pages = {285-291}, doi = {10.1016/j.micpath.2017.08.005}, pmid = {28803003}, issn = {1096-1208}, mesh = {Animals ; Bacteria/classification/genetics/*growth & development ; *Bacterial Physiological Phenomena ; *Biofilms ; Foodborne Diseases/*microbiology ; Humans ; Microbial Viability ; }, abstract = {Biofilm is a ubiquitous growth pattern of bacterial species survival but is notorious for its threat on public health and food contamination. Extensive studies of the biofilm structure, formation, quantification, quorum sensing system and underlying control strategies have been reported during the past decades. Insightful elucidation of the pathogenic features and characteristic of bacterial biofilm can facilitate in devising appropriate control strategies for biofilm eradication. Therefore, this review mainly summarized the pathogenic features of biofilms from food borne microorganisms, including the biomass (which could be quantified using crystal violet and fluorogenic dye Syto9 assays), viability (which could be determined by tetrazolium salts, fluorescein diacetate, resazurin staining and alamar blue assays) and matrix (which are commonly detected by dimethyl methylene blue and wheat germ agglutinin assays). In addition, three features were further compared with its particular benefits in specific application.}, } @article {pmid28802722, year = {2017}, author = {Ommen, P and Zobek, N and Meyer, RL}, title = {Quantification of biofilm biomass by staining: Non-toxic safranin can replace the popular crystal violet.}, journal = {Journal of microbiological methods}, volume = {141}, number = {}, pages = {87-89}, doi = {10.1016/j.mimet.2017.08.003}, pmid = {28802722}, issn = {1872-8359}, mesh = {*Biofilms ; *Biomass ; *Coloring Agents ; Gentian Violet ; *Phenazines ; Reproducibility of Results ; Staining and Labeling/*methods ; }, abstract = {Crystal violet staining is commonly used for quantification of biofilm formation, although it is highly toxic. Here we test safranin as a non-toxic replacement. Safranin staining provided similar results as crystal violet, but with higher reproducibility. We therefore recommend safranin staining for biofilm biomass quantification.}, } @article {pmid28800709, year = {2017}, author = {Chen, H and Kandel, PP and Cruz, LF and Cobine, PA and De La Fuente, L}, title = {The Major Outer Membrane Protein MopB Is Required for Twitching Movement and Affects Biofilm Formation and Virulence in Two Xylella fastidiosa strains.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {30}, number = {11}, pages = {896-905}, doi = {10.1094/MPMI-07-17-0161-R}, pmid = {28800709}, issn = {0894-0282}, support = {2015-67014-23085//USDA/International ; }, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Cell Aggregation ; Colony Count, Microbial ; Computer Simulation ; Gene Knockout Techniques ; Membrane Proteins/*metabolism ; Movement ; Mutation/genetics ; Plankton/growth & development ; Sequence Homology, Amino Acid ; Virulence ; Xylella/*pathogenicity/*physiology/ultrastructure ; }, abstract = {MopB is a major outer membrane protein (OMP) in Xylella fastidiosa, a bacterial plant pathogen that causes losses on many economically important crops. Based on in silico analysis, the uncharacterized MopB protein of X. fastidiosa contains a β-barrel structure with an OmpA-like domain and a predicted calcium-binding motif. Here, MopB function was studied by mutational analysis taking advantage of the natural competence of X. fastidiosa. Mutants of mopB were constructed in two different X. fastidiosa strains, the type strain Temecula and the more virulent WM1-1. Deletion of the mopB gene impaired cell-to-cell aggregation, surface attachment, and biofilm formation in both strains. Interestingly, mopB deletion completely abolished twitching motility. Electron microscopy of the bacterial cell surface revealed that mopB deletion eliminated type IV and type I pili formation, potentially caused by destabilization of the outer membrane. Both mopB mutants showed reduced virulence using tobacco (Nicotiana tabacum) as a host under greenhouse conditions. These results suggest that MopB has pleiotropic functions in biofilm formation and twitching motility and is important for virulence of X. fastidiosa.}, } @article {pmid28800553, year = {2017}, author = {Liu, Y and Zhu, Y and Jia, H and Yong, X and Zhang, L and Zhou, J and Cao, Z and Kruse, A and Wei, P}, title = {Effects of different biofilm carriers on biogas production during anaerobic digestion of corn straw.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 1}, pages = {445-451}, doi = {10.1016/j.biortech.2017.07.171}, pmid = {28800553}, issn = {1873-2976}, mesh = {Anaerobiosis ; *Biofilms ; *Biofuels ; Methane ; Zea mays ; }, abstract = {This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F420, and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers. The polypropylene fiber system maintained the highest biogas and methane production in the reactor, which was 44.80% and 49.84% higher than that noted in the control, respectively, during the entire anaerobic fermentation cycle. Meanwhile, the polypropylene fiber system exhibited the highest TS, VS, and COD removal efficiency. The results of high-throughput sequencing indicated that the dominant species in the polypropylene fiber system were Methanoregula and Methanobacterium.}, } @article {pmid28799927, year = {2017}, author = {Grujić, S and Vasić, S and Čomić, L and Ostojić, A and Radojević, I}, title = {Heavy metal tolerance and removal potential in mixed-species biofilm.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {76}, number = {3-4}, pages = {806-812}, doi = {10.2166/wst.2017.248}, pmid = {28799927}, issn = {0273-1223}, mesh = {Biofilms/*growth & development ; Escherichia coli/*drug effects/physiology ; Metals, Heavy/*metabolism/*toxicity ; Rhodotorula/*drug effects/physiology ; }, abstract = {The aim of the study was to examine heavy metal tolerance (Cd[2+], Zn[2+], Ni[2+] and Cu[2+]) of single- and mixed-species biofilms (Rhodotorula mucilaginosa and Escherichia coli) and to determine metal removal efficiency (Cd[2+], Zn[2+], Ni[2+], Cu[2+], Pb[2+] and Hg[2+]). Metal tolerance was quantified by crystal violet assay and results were confirmed by fluorescence microscopy. Metal removal efficiency was determined by batch biosorption assay. The tolerance of the mixed-species biofilm was higher than the single-species biofilms. Single- and mixed-species biofilms showed the highest sensitivity in the presence of Cu[2+] (E. coli-MIC 4 mg/ml, R. mucilaginosa-MIC 8 mg/ml, R. mucilaginosa/E. coli-MIC 64 mg/ml), while the highest tolerance was observed in the presence of Zn[2+] (E. coli-MIC 80 mg/ml, R. mucilaginosa-MIC 161 mg/ml, R. mucilaginosa-E. coli-MIC 322 mg/ml). The mixed-species biofilm exhibited better efficiency in removal of all tested metals than single-species biofilms. The highest efficiency in Cd[2+] removal was shown by the E. coli biofilm (94.85%) and R. mucilaginosa biofilm (97.85%), individually. The highest efficiency in Cu[2+] (99.88%), Zn[2+] (99.26%) and Pb[2+] (99.52%) removal was shown by the mixed-species biofilm. Metal removal efficiency was in the range of 81.56%-97.85% for the single- and 94.99%-99.88% for the mixed-species biofilm.}, } @article {pmid28799789, year = {2017}, author = {Yang, SC and Yen, FL and Wang, PW and Aljuffali, IA and Weng, YH and Tseng, CH and Fang, JY}, title = {Naphtho[1,2-b]furan-4,5-dione is a potent anti-MRSA agent against planktonic, biofilm and intracellular bacteria.}, journal = {Future microbiology}, volume = {12}, number = {}, pages = {1059-1073}, doi = {10.2217/fmb-2017-0044}, pmid = {28799789}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/drug effects ; Biofilms/*drug effects ; Cell Membrane/drug effects ; Cell Survival/drug effects ; Citric Acid Cycle ; Furans/chemistry/pharmacology ; Gluconeogenesis/drug effects ; Humans ; Keratinocytes/drug effects ; Macrophages/drug effects ; Methicillin-Resistant Staphylococcus aureus/cytology/*drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Transmission ; Molecular Docking Simulation ; Naphthoquinones/chemistry/*pharmacology ; Neutrophils/drug effects ; Oxacillin/pharmacology ; Proteomics ; Pseudomonas aeruginosa/drug effects ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects ; Vancomycin Resistance ; }, abstract = {AIM: Naphtho[1,2-b]furan-4,5-dione (N12D) and naphtho[2,3-b]furan-4,9-dione (N23D) are furanonaphthoquinone derivatives from natural resources. We examined the antimicrobial activity of N12D and N23D against drug-resistant Staphylococcus aureus.

MATERIALS & METHODS: Minimum inhibitory concentration, minimum bactericidal concentration, bacterial viability and agar diffusion assay were conducted against methicillin-resistant S. aureus (MRSA) and clinical isolates of vancomycin-resistant S. aureus.

RESULTS & CONCLUSION: The minimum inhibitory concentration of N12D and N23D against MRSA was 4.9-9.8 and 39 μM, respectively. With regard to the agar diffusion test, the inhibition zone of the quinone compounds was threefold larger than that of oxacillin. N12D was found to inhibit MRSA biofilm thickness from 24 to 16 μm as observed by confocal microscopy. N12D showed a significant reduction of the intracellular MRSA burden without decreasing the macrophage viability. The antibacterial mechanisms of N12D may be bacterial wall/membrane damage and disturbance of gluconeogenesis and the tricarboxylic acid cycle.}, } @article {pmid28798903, year = {2017}, author = {Singh, VK and Mishra, A and Jha, B}, title = {Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {337}, pmid = {28798903}, issn = {2235-2988}, mesh = {Anti-Bacterial Agents/isolation & purification/*metabolism ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Chromobacterium/drug effects/physiology ; Complex Mixtures/isolation & purification/metabolism ; Cyperus/microbiology ; Delftia/*chemistry/isolation & purification ; Gene Expression Profiling ; Locomotion/drug effects ; Microarray Analysis ; Pseudomonas aeruginosa/*drug effects/*physiology ; Quorum Sensing/*drug effects ; Real-Time Polymerase Chain Reaction ; Soil Microbiology ; Virulence Factors/*biosynthesis ; }, abstract = {Multidrug-resistance bacteria commonly use cell-to-cell communication that leads to biofilm formation as one of the mechanisms for developing resistance. Quorum sensing inhibition (QSI) is an effective approach for the prevention of biofilm formation. A Gram-negative bacterium, Delftia tsuruhatensis SJ01, was isolated from the rhizosphere of a species of sedge (Cyperus laevigatus) grown along the coastal-saline area. The isolate SJ01 culture and bacterial crude extract showed QSI activity in the biosensor plate containing the reference strain Chromobacterium violaceum CV026. A decrease in the violacein production of approximately 98% was detected with the reference strain C. violaceum CV026. The bacterial extract (strain SJ01) exhibited anti-quorum sensing activity and inhibited the biofilm formation of clinical isolates wild-type Pseudomonas aeruginosa PAO1 and P. aeruginosa PAH. A non-toxic effect of the bacterial extract (SJ01) was detected on the cell growth of the reference strains as P. aeruginosa viable cells were present within the biofilm. It is hypothesized that the extract (SJ01) may change the topography of the biofilm and thus prevent bacterial adherence on the biofilm surface. The extract also inhibits the motility, virulence factors (pyocyanin and rhamnolipid) and activity (elastase and protease) in P. aeruginosa treated with SJ01 extract. The potential active compound present was identified as 1,2-benzenedicarboxylic acid, diisooctyl ester. Microarray and transcript expression analysis unveiled differential expression of quorum sensing regulatory genes. The key regulatory genes, LasI, LasR, RhlI, and RhlR were down-regulated in the P. aeruginosa analyzed by quantitative RT-PCR. A hypothetical model was generated of the transcriptional regulatory mechanism inferred in P. aeruginosa for quorum sensing, which will provide useful insight to develop preventive strategies against the biofilm formation. The potential active compound identified, 1,2-benzenedicarboxylic acid, diisooctyl ester, has the potential to be used as an anti-pathogenic drug for the treatment of biofilm-forming pathogenic bacteria. For that, a detailed study is needed to investigate the possible applications.}, } @article {pmid28798773, year = {2017}, author = {Wang, JC and Cordero, J and Sun, Y and Aranke, M and Wolcott, R and Colmer-Hamood, JA and Hamood, AN}, title = {Planktonic Growth of Pseudomonas aeruginosa around a Dual-Species Biofilm Supports the Growth of Fusobacterium nucleatum within That Biofilm.}, journal = {International journal of otolaryngology}, volume = {2017}, number = {}, pages = {3037191}, pmid = {28798773}, issn = {1687-9201}, abstract = {PURPOSE: The goal of this study was to understand the potential interaction between Pseudomonas aeruginosa and Fusobacterium nucleatum within the middle ear.

METHODS: We examined the microbiota of ear fluid and tympanostomy tubes (TTs) obtained from patients with posttympanostomy tube otorrhea. We also examined biofilms formed by P. aeruginosa and F. nucleatum, singly or together, under aerobic or anaerobic conditions.

RESULTS: While the facultative anaerobe P. aeruginosa dominated the bacterial population within the ear fluid, strict anaerobes, including F. nucleatum, dominated bacterial populations within the TTs. F. nucleatum was able to grow under aerobic conditions only in the presence of P. aeruginosa, whose growth reduced the level of dissolved oxygen within the broth to nearly anoxic condition within 4 h after inoculation. The presence of P. aeruginosa allowed F. nucleatum to maintain its growth for 72 h within the dual-species biofilm but not within the planktonic growth. Visualization of the biofilms revealed coaggregation of P. aeruginosa and F. nucleatum.

CONCLUSION: Extrapolation of these results suggests that, within the middle ear fluid, the growth of P. aeruginosa produces the anaerobic conditions required for the growth of F. nucleatum, both within effusion and within biofilms.}, } @article {pmid28797969, year = {2017}, author = {Balaure, PC and Boarca, B and Popescu, RC and Savu, D and Trusca, R and Vasile, BȘ and Grumezescu, AM and Holban, AM and Bolocan, A and Andronescu, E}, title = {Bioactive mesoporous silica nanostructures with anti-microbial and anti-biofilm properties.}, journal = {International journal of pharmaceutics}, volume = {531}, number = {1}, pages = {35-46}, doi = {10.1016/j.ijpharm.2017.08.062}, pmid = {28797969}, issn = {1873-3476}, mesh = {Animals ; Anti-Infective Agents/*chemistry ; Biofilms/*drug effects ; Candida albicans/drug effects ; Cell Line ; Cross Infection ; *Drug Delivery Systems ; Escherichia coli/drug effects ; Fibroblasts/drug effects ; Mice ; Nanostructures/*chemistry ; Oils, Volatile/pharmacology ; Silicon Dioxide/*chemistry ; Staphylococcus aureus/drug effects ; X-Ray Diffraction ; }, abstract = {The increasing rate of antibiotic resistant bacteria associated with nosocomial infections in severely ill patients has urged the need for new antibacterial therapies. Nanostructured materials represent emerging innovative approaches to controlled delivery of different antimicrobial drugs. Delivery systems encapsulating natural compounds with antibacterial effects, such as essential oils have shown a great potential. Herein we report the development of SiO2 mesoporous nanosystems loaded with eucalyptus (EUC), orange (ORA), and cinnamon (CIN) essential oils. These systems were characterized with respect to morphology (using scanning electron microscopy, SEM, and transmission electron microscopy, TEM), porosity (by BET and TEM analysis), chemical composition (by X-ray diffraction, XRD, and Fourier transform infrared spectrometry, FTIR) and loading capacity (by thermogravimetric analysis, TGA). The anti-bacterial and anti-adherence effects were tested against clinically relevant microbial species (Staphylococcus aureus ATCC 25923; Escherichia coli ATCC 25922; and Candida albicans ATCC 10231), while the biocompatibility was evaluated by in vitro tests with L929 mouse fibroblast cells.}, } @article {pmid28797964, year = {2017}, author = {Lai, YS and Ontiveros-Valencia, A and Ilhan, ZE and Zhou, Y and Miranda, E and Maldonado, J and Krajmalnik-Brown, R and Rittmann, BE}, title = {Enhancing biodegradation of C16-alkyl quaternary ammonium compounds using an oxygen-based membrane biofilm reactor.}, journal = {Water research}, volume = {123}, number = {}, pages = {825-833}, doi = {10.1016/j.watres.2017.07.003}, pmid = {28797964}, issn = {1879-2448}, mesh = {Bacteria ; *Biofilms ; *Bioreactors ; Disinfectants ; Oxygen/*chemistry ; *Quaternary Ammonium Compounds ; }, abstract = {Quaternary ammonium compounds (QACs) (e.g., hexadecyltrimethyl-ammonium bromide, CTAB) are emerging contaminants with widespread use as surfactants and disinfectants. Because the initial step of QAC biodegradation is mono-oxygenation, QAC degraders require O2, but normal aeration leads to serious foaming. Here, we developed and tested an oxygen-based membrane biofilm reactor (O2-MBfR) that delivers O2 by diffusion through the walls of hollow-membranes to a biofilm accumulating on the outer surface of membranes. The O2-MBfR sustained QAC biodegradation even with high and toxic QAC input concentrations, up to 400 mg/L CTAB. Bubbleless O2 transfer completely eliminated foaming, and biofilm accumulation helped the QAC biodegraders resist toxicity. Pseudomonas, Achromobacter, Stenotrophomonas, and members of the Xanthomonadaceae family were dominant in the biofilm communities degrading CTAB, and their proportions depended on the O2-delivery capacity of the membranes. Bacteria capable of biodegrading QACs often harbor antibiotic resistance genes (ARGs) that help them avoid QAC toxicity. Gene copies of ARGs were detected in biofilms and liquid, but the levels of ARGs were 5- to 35-fold lower in the liquid than in the biofilm. In summary, the O2-MBfR achieved aerobic biodegradation of CTAB with neither foaming nor toxicity, and it also minimized the spread of ARGs.}, } @article {pmid28795881, year = {2017}, author = {Swanson, T and Wolcott, RD and Wallis, H and Woodmansey, EJ}, title = {Understanding biofilm in practice: a global survey of health professionals.}, journal = {Journal of wound care}, volume = {26}, number = {8}, pages = {426-440}, doi = {10.12968/jowc.2017.26.8.426}, pmid = {28795881}, issn = {0969-0700}, mesh = {Anti-Infective Agents/*therapeutic use ; *Biofilms ; *Clinical Competence ; *Debridement ; Disease Management ; *Health Personnel ; Humans ; Surveys and Questionnaires ; Wound Healing ; Wound Infection/diagnosis/epidemiology/*therapy ; }, abstract = {OBJECTIVE: The aim of this survey was to examine health professionals' views and practices relating to biofilm in chronic wounds.

METHOD: A global online survey was conducted to assess the current understanding of biofilm and wound management practices. The survey consisted of 20 questions designed to evaluate health professional knowledge of biofilm, perception and understanding of biofilm behaviour, detection and diagnosis, and treatment. Respondents were classified as 'specialists' if wounds were their primary focus and they developed protocols and determined formularies. Respondents were classified as 'generalists' if wounds were part of multiple indications they treat and they were able to choose wound care products from a restricted list of products. The Pearson's chi-square or Fisher's exact test was used to assess whether the responses were independent of the clinician role, health-care setting and country.

RESULTS: Overall, 3011 health professionals took part in the survey, of which 397 were excluded or disqualified. Of the remaining 2614 respondents, 1223 (46.8%) completed the entire survey. Although the majority of health professionals were aware of biofilm, knowledge gaps regarding its prevalence in chronic wounds were evident. In general, the majority indicated that they understood that biofilm is detrimental to wound healing. With the exception of wound stalling, there was a lack of consensus on other clinical signs in the detection and diagnosis of biofilm. Knowledge gaps were also evident over the treatment of biofilm and the efficacy of antimicrobial treatments, debridement and wound dressing.

CONCLUSION: Our results show that though there is a broad recognition of biofilm and its possible role in chronic wounds, there is still a need to educate and increase knowledge on recognition and treatment of biofilm.}, } @article {pmid28794323, year = {2017}, author = {Orii, T and Okazaki, T and Hata, N and Sugawara, K and Rahman, FA and Kuramitz, H}, title = {Development of an Attenuated Total Reflection Based Fiber-Optic Sensor for Real-time Sensing of Biofilm Formation.}, journal = {Analytical sciences : the international journal of the Japan Society for Analytical Chemistry}, volume = {33}, number = {8}, pages = {883-887}, doi = {10.2116/analsci.33.883}, pmid = {28794323}, issn = {1348-2246}, mesh = {*Biofilms ; *Fiber Optic Technology/instrumentation ; Surface Properties ; Time Factors ; Water/metabolism ; }, abstract = {A fiber-optic sensor capable of real-time monitoring of biofilm formation in water was developed. The sensor can be easily fabricated by removing the cladding of a multimode fiber optic to expose the core. The sensing action is based on the penetration of an evanescent wave through a biofilm formed on the surface of the exposed fiber core during total internal reflection. The proposed setup can be used to analyze the transmittance response over a wide wavelength range using a white-light source and a spectroscopy detector. The change in transmittance with respect to the biofilm formation on the fiber core surface was observed. The findings from this study showed that the sensor detection had better sensitivity at near-infrared wavelengths than at visible-light wavelengths. Moreover, the sensitivity of this sensor could be controlled by surface modifications of the core surface through electrostatic interactions, involving a silane coupling layer, polyanions, and polycations. The developed sensor was successfully applied to evaluating of the effectiveness of a commercial biofilm inhibitor.}, } @article {pmid28793308, year = {2017}, author = {Glazier, VE and Murante, T and Murante, D and Koselny, K and Liu, Y and Kim, D and Koo, H and Krysan, DJ}, title = {Genetic analysis of the Candida albicans biofilm transcription factor network using simple and complex haploinsufficiency.}, journal = {PLoS genetics}, volume = {13}, number = {8}, pages = {e1006948}, pmid = {28793308}, issn = {1553-7404}, support = {R01 AI098450/AI/NIAID NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Candida albicans/*genetics ; DNA-Binding Proteins/genetics/metabolism ; Fungal Proteins/genetics/*metabolism ; Gene Deletion ; *Gene Expression Regulation, Fungal ; Gene Regulatory Networks ; *Haploinsufficiency ; Transcription Factors/genetics/*metabolism ; }, abstract = {Biofilm formation by Candida albicans is a key aspect of its pathobiology and is regulated by an integrated network of transcription factors (Bcr1, Brg1, Efg1, Ndt80, Rob1, and Tec1). To understand the details of how the transcription factors function together to regulate biofilm formation, we used a systematic genetic interaction approach based on generating all possible double heterozygous mutants of the network genes and quantitatively analyzing the genetic interactions between them. Overall, the network is highly susceptible to genetic perturbation with the six network heterozygous mutants all showing alterations in biofilm formation (haploinsufficiency). In addition, many double heterozygous mutants are as severely affected as homozygous deletions. As a result, the network shows properties of a highly interdependent 'small-world' network that is highly efficient but not robust. In addition, these genetic interaction data indicate that TEC1 represents a network component whose expression is highly sensitive to small perturbations in the function of other networks TFs. We have also found that expression of ROB1 is dependent on both auto-regulation and cooperative interactions with other network TFs. Finally, the heterozygous NDT80 deletion mutant is hyperfilamentous under both biofilm and hyphae-inducing conditions in a TEC1-dependent manner. Taken together, genetic interaction analysis of this network has provided new insights into the functions of individual TFs as well as into the role of the overall network topology in its function.}, } @article {pmid28792642, year = {2017}, author = {Subirats, J and Triadó-Margarit, X and Mandaric, L and Acuña, V and Balcázar, JL and Sabater, S and Borrego, CM}, title = {Wastewater pollution differently affects the antibiotic resistance gene pool and biofilm bacterial communities across streambed compartments.}, journal = {Molecular ecology}, volume = {26}, number = {20}, pages = {5567-5581}, doi = {10.1111/mec.14288}, pmid = {28792642}, issn = {1365-294X}, mesh = {Bacteria/*classification/genetics ; *Biofilms ; Drug Resistance, Microbial/*genetics ; *Gene Pool ; *Genes, Bacterial ; High-Throughput Nucleotide Sequencing ; Rivers/chemistry/microbiology ; Sequence Analysis, DNA ; Spain ; *Wastewater ; Water Microbiology ; Water Pollution ; }, abstract = {Wastewater discharges introduce antibiotic residues and antibiotic-resistant bacteria (ARB) into surface waters. Both inputs directly affect the streambed resistome, either by exerting a selective pressure that favour the proliferation of resistant phenotypes or by enriching the resident communities with wastewater-associated ARB. Here, we investigated the impact of raw and treated urban wastewater discharges on epilithic (growing on rocks) and epipsammic (growing on sandy substrata) streambed biofilms. The effects were assessed by comparing control and impact sites (i) on the composition of bacterial communities; (ii) on the abundance of twelve antibiotic resistance genes (ARGs) encoding resistance to β-lactams, fluoroquinolones, sulphonamides, tetracyclines, macrolides and vancomycin, as well as the class 1 integron-integrase gene (intI1); (iii) on the occurrence of wastewater-associated bacteria, including putative pathogens, and their potential linkage to target ARGs. We measured more pronounced effects of raw sewage than treated wastewater at the three studied levels. This effect was especially noticeable in epilithic biofilms, which showed a higher contribution of wastewater-associated bacteria and ARB than in epipsammic biofilms. Comparison of correlation coefficients obtained between the relative abundance of both target ARGs and operational taxonomic units classified as either potential pathogens or nonpathogens yielded significant higher correlations between the former category and genes intI1, sul1, sul2 and ermB. Altogether, these results indicate that wastewater-associated micro-organisms, including potential pathogens, contribute to maintain the streambed resistome and that epilithic biofilms appear as sensitive biosensors of the effect of wastewater pollution in surface waters.}, } @article {pmid28792381, year = {2017}, author = {Wang, Y and Bandara, HMHN and Mikkelsen, D and Samaranayake, LP}, title = {Effects of tea extracts on the colonization behaviour of Candida species: attachment inhibition and biofilm enhancement.}, journal = {Journal of medical microbiology}, volume = {66}, number = {8}, pages = {1244-1252}, doi = {10.1099/jmm.0.000555}, pmid = {28792381}, issn = {1473-5644}, abstract = {Purpose. We assessed the effects of four different types of tea extracts (green, oolong, black and pu-erh tea) on cellular surface properties (hydrophobicity and auto-aggregation) and the colonization attributes (attachment and biofilm formation) of four strains of Candida albicans and three strains of Candida krusei.Methodology. The cellular surface properties were determined using spectrophotometry. The colonization activities were quantified using colorimetric viability assays and visualized using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).Results. The tea extracts, in general, reduced the hydrophobicity (by 8-66 %) and auto-aggregation (by 20-65 %), and inhibited the attachment of two C. krusei strains (by 41-88 %). Tea extracts enhanced the biofilm formation of one C. albicans and two C. krusei strains (by 1.4-7.5-fold). The observed reduction in hydrophobicity strongly correlated with the reduction in attachment of the two C. krusei strains (P<0.05). The ultrastructural images of the tea-treated C. krusei biofilm cells demonstrated central indentations, although they remained viable.Conclusion. The tea extracts have the ability to retard C. krusei adhesion to glass surfaces, possibly by reducing fungal cellular hydrophobicity, whilst paradoxically promoting biofilm formation. In practical terms, therefore, consumption of tea beverages appears to have a complex effect on oral candidal colonization.}, } @article {pmid28792234, year = {2017}, author = {Maske, TT and van de Sande, FH and Arthur, RA and Huysmans, MCDNJM and Cenci, MS}, title = {In vitro biofilm models to study dental caries: a systematic review.}, journal = {Biofouling}, volume = {33}, number = {8}, pages = {661-675}, doi = {10.1080/08927014.2017.1354248}, pmid = {28792234}, issn = {1029-2454}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Colony Count, Microbial ; Culture Media ; Dental Caries/*microbiology/prevention & control ; Dose-Response Relationship, Drug ; Humans ; *Models, Biological ; Reproducibility of Results ; Saliva, Artificial ; }, abstract = {The aim of this systematic review is to characterize and discuss key methodological aspects of in vitro biofilm models for caries-related research and to verify the reproducibility and dose-response of models considering the response to anti-caries and/or antimicrobial substances. Inclusion criteria were divided into Part I (PI): an in vitro biofilm model that produces a cariogenic biofilm and/or caries-like lesions and allows pH fluctuations; and Part II (PII): models showing an effect of anti-caries and/or antimicrobial substances. Within PI, 72.9% consisted of dynamic biofilm models, while 27.1% consisted of batch models. Within PII, 75.5% corresponded to dynamic models, whereas 24.5% corresponded to batch models. Respectively, 20.4 and 14.3% of the studies reported dose-response validations and reproducibility, and 32.7% were classified as having a high risk of bias. Several in vitro biofilm models are available for caries-related research; however, most models lack validation by dose-response and reproducibility experiments for each proposed protocol.}, } @article {pmid28790983, year = {2017}, author = {Mangalea, MR and Plumley, BA and Borlee, BR}, title = {Nitrate Sensing and Metabolism Inhibit Biofilm Formation in the Opportunistic Pathogen Burkholderia pseudomallei by Reducing the Intracellular Concentration of c-di-GMP.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1353}, pmid = {28790983}, issn = {1664-302X}, abstract = {The opportunistic pathogen Burkholderia pseudomallei is a saprophytic bacterium and the causative agent of melioidosis, an emerging infectious disease associated with high morbidity and mortality. Although melioidosis is most prevalent during the rainy season in endemic areas, domestic gardens and farms can also serve as a reservoir for B. pseudomallei during the dry season, in part due to irrigation and fertilizer use. In the environment, B. pseudomallei forms biofilms and persists in soil near plant root zones. Biofilms are dynamic bacterial communities whose formation is regulated by extracellular cues and corresponding changes in the nearly universal secondary messenger cyclic dimeric GMP. Recent studies suggest B. pseudomallei loads are increased by irrigation and the addition of nitrate-rich fertilizers, whereby such nutrient imbalances may be linked to the transmission epidemiology of this important pathogen. We hypothesized that exogenous nitrate inhibits B. pseudomallei biofilms by reducing the intracellular concentration of c-di-GMP. Bioinformatics analyses revealed B. pseudomallei 1026b has the coding capacity for nitrate sensing, metabolism, and transport distributed on both chromosomes. Using a sequence-defined library of B. pseudomallei 1026b transposon insertion mutants, we characterized the role of denitrification genes in biofilm formation in response to nitrate. Our results indicate that the denitrification pathway is implicated in B. pseudomallei biofilm growth dynamics and biofilm formation is inhibited by exogenous addition of sodium nitrate. Genomics analysis identified transposon insertional mutants in a predicted two-component system (narX/narL), a nitrate reductase (narGH), and a nitrate transporter (narK-1) required to sense nitrate and alter biofilm formation. Additionally, the results presented here show that exogenous nitrate reduces intracellular levels of the bacterial second messenger c-di-GMP. These results implicate the role of nitrate sensing in the regulation of a c-di-GMP phosphodiesterase and the corresponding effects on c-di-GMP levels and biofilm formation in B. pseudomallei 1026b.}, } @article {pmid28790201, year = {2017}, author = {Lowery, NV and McNally, L and Ratcliff, WC and Brown, SP}, title = {Division of Labor, Bet Hedging, and the Evolution of Mixed Biofilm Investment Strategies.}, journal = {mBio}, volume = {8}, number = {4}, pages = {}, pmid = {28790201}, issn = {2150-7511}, support = {//Wellcome Trust/United Kingdom ; WT095831//Wellcome Trust/United Kingdom ; }, mesh = {Adaptation, Physiological ; Bacteria/*genetics/growth & development/metabolism ; *Bacterial Physiological Phenomena/genetics ; *Biofilms ; *Biological Evolution ; Environment ; *Genetic Fitness ; Models, Biological ; Phenotype ; }, abstract = {Bacterial cells, like many other organisms, face a tradeoff between longevity and fecundity. Planktonic cells are fast growing and fragile, while biofilm cells are often slower growing but stress resistant. Here we ask why bacterial lineages invest simultaneously in both fast- and slow-growing types. We develop a population dynamic model of lineage expansion across a patchy environment and find that mixed investment is favored across a broad range of environmental conditions, even when transmission is entirely via biofilm cells. This mixed strategy is favored because of a division of labor where exponentially dividing planktonic cells can act as an engine for the production of future biofilm cells, which grow more slowly. We use experimental evolution to test our predictions and show that phenotypic heterogeneity is persistent even under selection for purely planktonic or purely biofilm transmission. Furthermore, simulations suggest that maintenance of a biofilm subpopulation serves as a cost-effective hedge against environmental uncertainty, which is also consistent with our experimental findings.IMPORTANCE Cell types specialized for survival have been observed and described within clonal bacterial populations for decades, but why are these specialists continually produced under benign conditions when such investment comes at a high reproductive cost? Conversely, when survival becomes an imperative, does it ever benefit the population to maintain a pool of rapidly growing but vulnerable planktonic cells? Using a combination of mathematical modeling, simulations, and experiments, we find that mixed investment strategies are favored over a broad range of environmental conditions and rely on a division of labor between cell types, where reproductive specialists amplify survival specialists, which can be transmitted through the environment with a limited mortality rate. We also show that survival specialists benefit rapidly growing populations by serving as a hedge against unpredictable changes in the environment. These results help to clarify the general evolutionary and ecological forces that can generate and maintain diverse subtypes within clonal bacterial populations.}, } @article {pmid28787684, year = {2017}, author = {Liu, S and Feng, X and Gu, F and Li, X and Wang, Y}, title = {Sequential reduction/oxidation of azo dyes in a three-dimensional biofilm electrode reactor.}, journal = {Chemosphere}, volume = {186}, number = {}, pages = {287-294}, doi = {10.1016/j.chemosphere.2017.08.001}, pmid = {28787684}, issn = {1879-1298}, mesh = {Azo Compounds/*metabolism ; *Biofilms ; Coloring Agents/*metabolism ; Electrodes ; Electrolysis ; Naphthalenesulfonates/metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/instrumentation/*methods ; }, abstract = {By combining sequential anaerobic-aerobic reactor and penetrable cathode-anode operation, a novel anaerobic/aerobic sequencing three-dimensional biofilm electrode reactor (3D-BER) was developed to evaluate the degradation of azo dye reactive brilliant red X-3B (RBRX-3B). In the bottom cathodic region, anaerobic reductive conditions and H2 were produced for the bioreduction of azo dyes; in the top anodic region, aerobic oxidative conditions and O2 were produced for the mineralization of dye intermediates. Due to the supply of electrical power, electrons could be mediated via electrolysis of water or directly transfer between electrodes and microbe cells. The biofilm immobilized on the surface of the cathode utilized electrode or H2 as electron donors and accelerated the rate of RBRX-3B reduction, and the decolorization rate was significantly increased 2.6-3.7 fold, reaching at 2.52-3.39 mol/m[3]/d at an energy consumption of 0.15 kWh/mol RBRX-3B. RBRX-3B was reductively cleaved into aromatic amines at the biocathode and these amines were effectively removed at the bioanode. Acute toxicity tests showed that the intermediates of RBRX-3B were more toxic when compared with the initial influent, and the 3D-BER effluent exhibited much lower toxicity (5% inhibition of bioluminescence of Vibrio fisheri) than the electrochemical and biological effluent (65% and 30% inhibition, respectively). These findings suggest the novel 3D-BER may provide a promising alternative to remove azo dyes in dyeing wastewater.}, } @article {pmid28787633, year = {2017}, author = {Monteiro, MP and Clerici, JH and Sahoo, PK and Cesar, CL and de Souza, AA and Cotta, MA}, title = {Stiffness signatures along early stages of Xylella fastidiosa biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {159}, number = {}, pages = {174-182}, doi = {10.1016/j.colsurfb.2017.07.075}, pmid = {28787633}, issn = {1873-4367}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Polymers/pharmacology ; Xylella/*drug effects ; }, abstract = {The pathogenicity of Xylella fastidiosa is associated with its systematic colonization of the plant xylem, forming bacterial biofilms. Mechanisms of bacterial transport among different xylem vessels, however, are not completely understood yet, but are strongly influenced by the presence of extracellular polymeric substances (EPS), which surrounds the assembly of cells forming the biofilm. In this work, we show quantitative measurements on the elastic properties of the system composed by EPS and bacterial cell. In order to investigate the mechanical properties of this system, force spectroscopy and confocal Raman measurements were carried out during Xylella fastidiosa subsp. pauca initial stages of adhesion and cluster formation. We show that stiffness progressively decreases with increasing culture growth time, from two to five days. For early adhesion samples, stiffness values are quite different at the bacterial polar and body regions. Lower stiffness values at the cell pole suggest a flexible mechanical response at this region, associated with first cell adhesion to a surface. These results correlate very well with our observations of cell motion within microchannels, under conditions simulating xylem flow. Both the oscillatory movement of vertically attached single cells, as well as the transport of cell clusters within the biofilm matrix can be explained by the presence of softer materials at the cell pole and EPS matrix. Our results may thus add to a more detailed understanding of mechanisms used by cells to migrate among vessels in plant xylem.}, } @article {pmid28787014, year = {2017}, author = {Murray, J and Muruko, T and Gill, CIR and Kearney, MP and Farren, D and Scott, MG and McMullan, G and Ternan, NG}, title = {Evaluation of bactericidal and anti-biofilm properties of a novel surface-active organosilane biocide against healthcare associated pathogens and Pseudomonas aeruginosa biolfilm.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0182624}, pmid = {28787014}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/*growth & development ; Cross Infection/*microbiology ; Microbial Sensitivity Tests ; Organosilicon Compounds/*chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Surface Properties ; }, abstract = {Healthcare acquired infections (HAI) pose a great threat in hospital settings and environmental contamination can be attributed to the spread of these. De-contamination and, significantly, prevention of re-contamination of the environment could help in preventing/reducing this threat. Goldshield (GS5) is a novel organosilane biocide marketed as a single application product with residual biocidal activity. We tested the hypothesis that GS5 could provide longer-term residual antimicrobial activity than existing disinfectants once applied to surfaces. Thus, the residual bactericidal properties of GS5, Actichlor and Distel against repeated challenge with Staphylococcus aureus ATCC43300 were tested, and showed that GS5 alone exhibited longer-term bactericidal activity for up to 6 days on 316I stainless steel surfaces. Having established efficacy against S. aureus, we tested GS5 against common healthcare acquired pathogens, and demonstrated that, on average, a 1 log10 bactericidal effect was exhibited by GS5 treated surfaces, although biocidal activity varied depending upon the surface type and the species of bacteria. The ability of GS5 to prevent Pseudomonas aeruginosa biofilm formation was measured in standard microtitre plate assays, where it had no significant effect on either biofilm formation or development. Taken together the data suggests that GS5 treatment of surfaces may be a useful means to reducing bacterial contamination in the context of infection control practices.}, } @article {pmid28785939, year = {2018}, author = {Anand, R and Moss, RB and Sass, G and Banaei, N and Clemons, KV and Martinez, M and Stevens, DA}, title = {Small Colony Variants of Pseudomonas aeruginosa Display Heterogeneity in Inhibiting Aspergillus fumigatus Biofilm.}, journal = {Mycopathologia}, volume = {183}, number = {1}, pages = {263-272}, pmid = {28785939}, issn = {1573-0832}, support = {CIMR no. 3777//Child Health Research Institute, Stanford Transdisciplinary Initiatives Program/ ; CIMR no. 3770//John Flatley/ ; }, mesh = {*Antibiosis ; Aspergillus fumigatus/*drug effects/*physiology ; Biofilms/*drug effects/*growth & development ; Culture Media/*chemistry ; Pseudomonas aeruginosa/growth & development/metabolism/*physiology ; }, abstract = {Pseudomonas aeruginosa and Aspergillus fumigatus are major microbes in cystic fibrosis (CF). We reported non-mucoid P. aeruginosa isolates more inhibitory to A. fumigatus than mucoid ones. Another CF P. aeruginosa phenotype, small colony variants (SCVs), is an unknown factor in intermicrobial competition with A. fumigatus. Clinical SCV isolates and reference CF non-mucoid isolate (Pa10, producing normal-sized colonies) were compared. Live cells of P. aeruginosa or filtrates from P. aeruginosa planktonic or biofilm cultures were co-incubated with A. fumigatus growing under conditions allowing biofilm formation or with preformed biofilm. Metabolic activity of A. fumigatus biofilm was then measured. When necessary, assays were done after adjustment for growth differences by adding fresh medium to the planktonic culture filtrate. Pyoverdine determinations were performed spectrophotometrically on the planktonic culture filtrates. In all experimental conditions (live cells and planktonic or biofilm culture filtrates of P. aeruginosa versus A. fumigatus biofilm formation or preformed biofilm), three SCV isolates were less inhibitory than Pa10, two equal or more inhibitory. Adjusting planktonic culture filtrates for growth differences showed SCV inhibition differences variably related to growth or deficient inhibitor production. Studies suggested the principal P. aeruginosa inhibitor to be pyoverdine. SCV isolates appear heterogeneous in their capacity to inhibit A. fumigatus biofilm. SCV isolates can be important in the CF microbiome, because they are capable of intermicrobial inhibition.}, } @article {pmid28784983, year = {2017}, author = {Ge, G and Zhao, J and Li, X and Ding, X and Chen, A and Chen, Y and Hu, B and Wang, S}, title = {Effects of influent COD/N ratios on nitrous oxide emission in a sequencing biofilm batch reactor for simultaneous nitrogen and phosphorus removal.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {7417}, pmid = {28784983}, issn = {2045-2322}, mesh = {Aerobiosis ; Anaerobiosis ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification ; Hydroxybutyrates/metabolism ; Nitrogen/*metabolism ; Nitrous Oxide/*metabolism ; Organic Chemicals/analysis ; Phosphorus/*metabolism ; Polyesters/metabolism ; Water/chemistry ; *Water Purification ; }, abstract = {The characteristics of N2O emissions from an anaerobic/aerobic/anoxic (A/O/A) sequencing biofilm batch reactor (SBBR) were investigated under different influent COD/nitrogen (C/N) ratios (from 1-4). Results indicated that the C/N ratios affected the quantity of polyhydroxybutyrate (PHB) and residual organic substances after the anaerobic period, resulting in the largest N2O emission during aerobic period occurred at a C/N of 2. Moreover, during the anoxic PHB-driven denitrification period, the rapid decline in the dissolved N2O concentration indicated that the nitrite inhibition threshold for N2O reduction increased with the increased C/N ratios, which means the higher influent C/N ratios could lower the inhibition of nitrite on N2O reduction. Finally, more PHB and residual organic substances were provided to denitrification at a high C/N ratio, resulting in less total N2O emission was achieved at a high C/N ratio in the A/O/A SBBR.}, } @article {pmid28783781, year = {2017}, author = {Feyereisen, GW and Christianson, LE and Moorman, TB and Venterea, RT and Coulter, JA}, title = {Plastic Biofilm Carrier after Corn Cobs Reduces Nitrate Loading in Laboratory Denitrifying Bioreactors.}, journal = {Journal of environmental quality}, volume = {46}, number = {4}, pages = {915-920}, doi = {10.2134/jeq2017.02.0060}, pmid = {28783781}, issn = {0047-2425}, mesh = {*Biofilms ; *Bioreactors ; Denitrification ; Nitrates/*chemistry ; Nitrogen ; *Plastics ; Zea mays ; }, abstract = {Nitrate-nitrogen (nitrate-N) removal rates can be increased substantially in denitrifying bioreactors with a corn (L.) cob bed medium compared with woodchips; however, additional organic carbon (C) is released into the effluent. This laboratory column experiment was conducted to test the performance of a postbed chamber of inert plastic biofilm carrier (PBC) after corn cobs (CC) to extend the area of biofilm colonization, enhance nitrate-N removal, lower total organic C losses, and reduce nitrous oxide (NO) production at warm (15.5°C) and cold (1.5°C) temperatures. Treatments were CC only and CC plus PBC in series (CC-PBC). Across the two temperatures, nitrate-N load removal was 21% greater with CC-PBC than CC, with 54 and 44% of total nitrate N load, respectively. However, total organic C concentrations and loads were not significantly different between treatments. Colonization of the PBC by denitrifiers occurred, although gene abundance at the outlet (PBC) was less than at the inlet (CC). The PBC chamber increased nitrate-N removal rate and reduced cumulative NO production at 15.5°C, but not at 1.5°C. Across temperatures and treatments, NO production was 0.9% of nitrate-N removed. Including an additional chamber filled with PBC downstream from the CC bioreactor provided benefits in terms nitrate-N removal but did not achieve C removal. The presence of excess C, as well as available nitrate, in the PBC chamber suggests another unidentified limiting factor for nitrate removal.}, } @article {pmid28782178, year = {2017}, author = {Juhlin, A and Svensson, S and Thomsen, P and Trobos, M}, title = {Staphylococcal biofilm gene expression on biomaterials - A methodological study.}, journal = {Journal of biomedical materials research. Part A}, volume = {105}, number = {12}, pages = {3400-3412}, doi = {10.1002/jbm.a.36171}, pmid = {28782178}, issn = {1552-4965}, mesh = {Bacterial Adhesion ; Biocompatible Materials/*adverse effects ; Biofilms/*growth & development ; Central Venous Catheters/*adverse effects ; *Gene Expression Regulation, Bacterial ; Humans ; Polyurethanes/adverse effects ; Staphylococcal Infections/*etiology/microbiology ; Staphylococcus aureus/genetics/*physiology ; Staphylococcus epidermidis/genetics/*physiology ; Surface Properties ; Titanium/adverse effects ; }, abstract = {The combination of increased healthcare access, universal aging, and infallible therapy demands, synergistically drive the need for the development of biomaterial technologies that mitigate the challenge of biomaterial-associated infections (BAI). Staphylococcus epidermidis and Staphylococcus aureus account for the majority of BAI due to their ability to accumulate in adherent multilayered biofilm. This investigation details the development of gene expression assays to evaluate the genetic processes of attachment, accumulation, maturation, and dispersal phases of biofilms on biomaterials in vitro, while abiding by the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines. The biofilm formation of S. epidermidis on polyurethane (PU) central venous catheters and S. aureus on machined titanium (Ti) was examined in terms of gene expression at early and late time points. The results provided insight into how each stage of biofilm formation is orchestrated over time on these biomaterials in vitro. Furthermore, the results suggested that mechanical RNA extraction, organic solvents, elimination of genomic DNA, and preamplification are advisable strategies to implement for biofilm gene expression analysis. It is concluded that this method can be employed for the assessment of biofilm-biomaterial interactions at the molecular level. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3400-3412, 2017.}, } @article {pmid28779678, year = {2017}, author = {Ma, W and Han, Y and Ma, W and Han, H and Zhu, H and Xu, C and Li, K and Wang, D}, title = {Enhanced nitrogen removal from coal gasification wastewater by simultaneous nitrification and denitrification (SND) in an oxygen-limited aeration sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 1}, pages = {84-91}, doi = {10.1016/j.biortech.2017.07.083}, pmid = {28779678}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Coal ; *Denitrification ; Nitrification ; Nitrogen ; Oxygen ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Simultaneous nitrification and denitrification (SND) for treating coal gasification wastewater (CGW) was achieved successfully in a lab-scale sequencing batch biofilm reactor (SBBR) by oxygen-limited aeration. SND efficiency increased gradually with the concentration of dissolved oxygen (DO) decreased from 4.5mg/L to 0.35mg/L. The maximum SND efficiency of 81.23% was obtained at DO concentration of 0.35mg/L, and the corresponding removal efficiency of NH4[+]-N and TN reached 76.91% and 70.23%, respectively. Meanwhile, COD was removed significantly and toxic compounds were degraded into biodegradable substances, which relieved effectively the inhibition on nitrogen removal. The results indicated that oxygen-limited condition performed greater toxic compounds and nitrogen removal compared with the aerobic condition. Furthermore, the results of scanning electron microscopic (SEM) and microbial community structure confirmed robust biofilm formation provided a suitable anoxic micro-environment for co-existence of nitrifying and denitrifying bacteria and organics degradation bacteria in the reactor at oxygen-limited condition.}, } @article {pmid28779672, year = {2017}, author = {Zheng, Y and Huang, Y and Liao, Q and Fu, Q and Xia, A and Zhu, X}, title = {Impact of the accumulation and adhesion of released oxygen during Scenedesmus obliquus photosynthesis on biofilm formation and growth.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 1}, pages = {198-205}, doi = {10.1016/j.biortech.2017.07.145}, pmid = {28779672}, issn = {1873-2976}, mesh = {*Biofilms ; Oxygen ; *Photosynthesis ; Polytetrafluoroethylene ; *Scenedesmus ; }, abstract = {Microalgae cells release O2 during photosynthesis. The gas can accumulate and adhere in form of bubbles, which affect the transport of nutrients in the biofilm and the biofilm microstructure. To investigate the reasons for the adhesion of these oxygen bubbles and their impact on biofilm, polytetrafluoroethylene (PTFE) emulsion was sprayed onto glass surface to change the parameters for gas accumulation and adhesion. The results indicated gas could aggregate into bubbles and adhere to hydrophobic and rough surface. The bubble behaviors caused the biofilm to be porous (with a microporosity of 9.43-20.94%). The biomass concentration of the more porous biofilm increased by 9.26% to 22.42gm[-2] on 1% PTFE-treated surface compared to that on an untreated surface. However, with an increase in PTFE concentration, the amount of adhered bubbles increased. More microalgae cells in biofilms were carried up by bubbles. The biofilm concentration on 5% PTFE-treated surface decreased by 15.30%.}, } @article {pmid28778504, year = {2017}, author = {Albuquerque, MTP and Nagata, J and Bottino, MC}, title = {Antimicrobial Efficacy of Triple Antibiotic-eluting Polymer Nanofibers against Multispecies Biofilm.}, journal = {Journal of endodontics}, volume = {43}, number = {9S}, pages = {S51-S56}, pmid = {28778504}, issn = {1878-3554}, support = {K08 DE023552/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects ; Ciprofloxacin/*administration & dosage ; Dentin/*microbiology ; Metronidazole/*administration & dosage ; Minocycline/*administration & dosage ; *Nanofibers ; Polymers ; }, abstract = {The elimination of microbial flora in cases of immature permanent teeth with necrotic pulp is both key and a challenging goal for the long-term success of regenerative therapy. Recent research has focused on the development of cell-friendly intracanal drug delivery systems. This in vitro study aimed to investigate the antimicrobial action of 3-dimensional (3D) tubular-shaped triple antibiotic-eluting nanofibrous constructs against a multispecies biofilm on human dentin. Polydioxanone polymer solutions, antibiotic-free or incorporated with metronidazole, ciprofloxacin, and minocycline, were electrospun into 3D tubular-shaped constructs. A multispecies biofilm consisting of Actinomyces naeslundii, Streptococcus sanguinis, and Enterococcus faecalis was forced inside the dentinal tubules via centrifugation in a dentin slice in vitro model. The infected specimens were exposed to 2 experimental groups (ie, 3D tubular-shaped triple antibiotic-eluting constructs and triple antibiotic paste [TAP]) and 2 control groups (7-day biofilm untreated and antibiotic-free 3D tubular-shaped constructs). Biofilm elimination was quantitatively analyzed with confocal laser scanning microscopy. Confocal laser scanning microscopic (CLSM) analysis showed a dense population of viable (green) bacteria adhered to dentin and penetrated into the dentinal tubules. Upon 3D tubular-shaped triple antibiotic-eluting nanofibrous construct exposure, nearly complete elimination of viable bacteria on the dentin surface and inside the dentinal tubules was shown in the CLSM images, which was similar (P < .05) to the bacterial death promoted by the TAP group but significantly greater when compared with both the antibiotic-free 3D tubular-shaped constructs and the control (saline). The proposed 3D tubular-shaped antibiotic-eluting construct showed pronounced antimicrobial effects against the multispecies biofilm tested and therefore holds significant clinical potential as a disinfection strategy before regenerative endodontics.}, } @article {pmid28777989, year = {2017}, author = {Tang, B and Zhao, Y and Bin, L and Huang, S and Fu, F}, title = {Variation of the characteristics of biofilm on the semi-suspended bio-carrier produced by a 3D printing technique: Investigation of a whole growing cycle.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 1}, pages = {40-47}, doi = {10.1016/j.biortech.2017.07.132}, pmid = {28777989}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Printing, Three-Dimensional ; }, abstract = {The presented investigation focused on exploring the characteristics of the biofilm formed on a novel semi-suspended bio-carrier and revealing their variation during the whole growing cycle. This used semi-suspended bio-carrier was designed to be a spindle shape, and then fabricated by using a 3D printing technique. Results indicated the bio-carrier provided a suitable environment for the attachment of diverse microorganisms. During the experimental period lasted for 45days, the biofilm quickly attached on the surface of the bio-carrier and grew to maturity, but its characteristics, including the chemical compositions, adhesion force, surface roughness, structure of microbial communities, varied continuously along with the operational time, which greatly influenced the performance of the bioreactor. The shape and structure of bio-carrier, and the shearing force caused by the aeration are important factors that influence the microbial community and its structure, and also heavily affect the formation and growth of biofilm.}, } @article {pmid28775817, year = {2017}, author = {Akbari-Ayezloy, E and Hosseini-Jazani, N and Yousefi, S and Habibi, N}, title = {Eradication of methicillin resistant S. aureus biofilm by the combined use of fosfomycin and β-chloro-L-alanine.}, journal = {Iranian journal of microbiology}, volume = {9}, number = {1}, pages = {1-10}, pmid = {28775817}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Biofilm formation is an important virulence factor for methicillin-resistant Staphylococcus aureus (MRSA). Fosfomycin is a borad-spectrum antibiotic with inhibitory effects on biofilm production and β-Chloro-L-alanine (β-CLA) is an amino acid analog. The aim of this study was to determine effect of the combination of fosfomycin and β-CLA on biofilm production by MRSA isolates. Also, the clonal relatedness of the isolates was evaluated.

MATERIALS AND METHODS: To determine the ability of biofilm production by 42 MRSA isolates, microtiter plate method was used. Antibacterial activities of fosfomycin and β-CLA were investigated by determining MICs and MBCs. Antibiofilm activities were measured in the presence of sub-MIC concentrations of fosfomycin, β-CLA or a combination of both. RAPD-PCR was used for investigating the clonal relationship between isolates by the two specific primers.

RESULTS: 21.4% of isolates were strong and 5% were moderate biofilm producers. The effect of fosfomycin plus β-CLA treatment on biofilm production was significantly different from non-treated, fosfomycin and β-CLA groups (p=0.00, 0.004 and 0.000 respectively). RAPD-PCR analysis revealed that the RAPD1 primer had more discriminatory power. The Sizes of RAPD-PCR bands ranged from 150 bp to 1500 bp and the number of bands varied from 1 to 13.

CONCLUSION: Clonal relatedness of isolates showed that the majority of biofilm producing isolates had identical pattern and only three isolates showed more than 80% similarity. The combination of fosfomycin and β-CLA could be introduced as an excellent mixture for eradication of MRSA biofilms in vitro.}, } @article {pmid28774481, year = {2017}, author = {Dieser, SA and Fessia, AS and Ferrari, MP and Raspanti, CG and Odierno, LM}, title = {Streptococcus uberis: In vitro biofilm production in response to carbohydrates and skim milk.}, journal = {Revista Argentina de microbiologia}, volume = {49}, number = {4}, pages = {305-310}, doi = {10.1016/j.ram.2017.04.007}, pmid = {28774481}, issn = {0325-7541}, mesh = {Animals ; *Biofilms ; Carbohydrates ; Cattle ; Female ; *Mastitis, Bovine/microbiology ; *Milk/microbiology ; *Streptococcal Infections/veterinary ; Streptococcus ; }, abstract = {Streptococcus uberis has become one of the most important environmental pathogens associated with clinical and subclinical bovine mastitis. Biofilm confers to bacteria more resistance to physical and chemical agents as well as to different mechanisms of the innate immune system. The aim of this work was to evaluate the ability of in vitro biofilm production in 32 S. uberis isolates from bovine mastitis and identified by biochemical tests and subsequently confirmed by the amplification of the pauA gene. The isolates were cultivated in TMP broth and TMP broth with the addition of 0.5% glucose, 1% sucrose, 1% lactose or 0.5% skim milk in microtiter plates stained with crystal violet. We demonstrated that S. uberis isolated from bovine mastitis are able to produce biofilms in TMP broth and, also that biofilm formation by S. uberis can be significantly enhanced by the addition of 0.5% glucose or 1% sucrose to TMP broth. This may suggest that the carbohydrates in milk or within the ruminant gut might affect the growth mode of S. uberis. In addition, our results showed that in vitro biofilm production under different conditions of supplementation displays variation among the isolates and that each isolate shows a particular profile of biofilm production. This phenotypic heterogeneity in biofilm production exhibited by S. uberis could at least partly explain why this bacterium has the ability to adapt to different niches facilitating survival to diverse and stressful conditions.}, } @article {pmid28773945, year = {2016}, author = {Kanematsu, H and Kudara, H and Kanesaki, S and Kogo, T and Ikegai, H and Ogawa, A and Hirai, N}, title = {Application of a Loop-Type Laboratory Biofilm Reactor to the Evaluation of Biofilm for Some Metallic Materials and Polymers such as Urinary Stents and Catheters.}, journal = {Materials (Basel, Switzerland)}, volume = {9}, number = {10}, pages = {}, pmid = {28773945}, issn = {1996-1944}, abstract = {A laboratory biofilm reactor (LBR) was modified to a new loop-type closed system in order to evaluate novel stents and catheter materials using 3D optical microscopy and Raman spectroscopy. Two metallic specimens, pure nickel and cupronickel (80% Cu-20% Ni), along with two polymers, silicone and polyurethane, were chosen as examples to ratify the system. Each set of specimens was assigned to the LBR using either tap water or an NB (Nutrient broth based on peptone from animal foods and beef extract mainly)-cultured solution with E-coli formed over 48-72 h. The specimens were then analyzed using Raman Spectroscopy. 3D optical microscopy was employed to corroborate the Raman Spectroscopy results for only the metallic specimens since the inherent roughness of the polymer specimens made such measurements difficult. The findings suggest that the closed loop-type LBR together with Raman spectroscopy analysis is a useful method for evaluating biomaterials as a potential urinary system.}, } @article {pmid28773758, year = {2016}, author = {Ogawa, A and Kanematsu, H and Sano, K and Sakai, Y and Ishida, K and Beech, IB and Suzuki, O and Tanaka, T}, title = {Effect of Silver or Copper Nanoparticles-Dispersed Silane Coatings on Biofilm Formation in Cooling Water Systems.}, journal = {Materials (Basel, Switzerland)}, volume = {9}, number = {8}, pages = {}, pmid = {28773758}, issn = {1996-1944}, abstract = {Biofouling often occurs in cooling water systems, resulting in the reduction of heat exchange efficiency and corrosion of the cooling pipes, which raises the running costs. Therefore, controlling biofouling is very important. To regulate biofouling, we focus on the formation of biofilm, which is the early step of biofouling. In this study, we investigated whether silver or copper nanoparticles-dispersed silane coatings inhibited biofilm formation in cooling systems. We developed a closed laboratory biofilm reactor as a model of a cooling pipe and used seawater as a model for cooling water. Silver or copper nanoparticles-dispersed silane coating (Ag coating and Cu coating) coupons were soaked in seawater, and the seawater was circulated in the laboratory biofilm reactor for several days to create biofilms. Three-dimensional images of the surface showed that sea-island-like structures were formed on silane coatings and low concentration Cu coating, whereas nothing was formed on high concentration Cu coatings and low concentration Ag coating. The sea-island-like structures were analyzed by Raman spectroscopy to estimate the components of the biofilm. We found that both the Cu coating and Ag coating were effective methods to inhibit biofilm formation in cooling pipes.}, } @article {pmid28773689, year = {2016}, author = {Barry, DM and McGrath, PB}, title = {Rotation Disk Process to Assess the Influence of Metals and Voltage on the Growth of Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {9}, number = {7}, pages = {}, pmid = {28773689}, issn = {1996-1944}, abstract = {Biofilms consist of not only bacteria but also extracellular polymer substrates (EPS). They are groups of microorganisms that adhere to each other on a surface, especially as a result of exposure to water and bacteria. They can pose health risks to humans as they grow in hospital settings that include medical supplies and devices. In a previous study, the researchers discovered that bacteria/biofilm grew well on wetted external latex, male catheters. These results concerned the investigators and encouraged them to find ways for prohibiting the growth of bacteria/biofilm on the male catheters (which are made of natural rubber). They carried out a new study to assess the influence of metals and voltage for the growth of bacteria on these latex samples. For this purpose, a unique Rotation Disk Reactor was used to accelerate biofilm formation on external male catheter samples. This setup included a dip tank containing water and a rotating wheel with the attached latex samples (some of which had single electrodes while others had paired electrodes with applied voltage). The process allowed the samples to become wetted and also exposed them to microorganisms in the ambient air during each revolution of the wheel. The results (as viewed from SEM images) showed that when compared to the control sample, the presence of metals (brass, stainless steel, and silver) was generally effective in preventing bacterial growth. Also the use of voltage (9.5 volt battery) essentially eliminated the appearance of rod shaped bacteria in some of the samples. It can be concluded that the presence of metals significantly reduced bacterial growth on latex and the application of voltage was able to essentially eliminate bacteria, providing appropriate electrode combinations were used.}, } @article {pmid28772791, year = {2017}, author = {Chen, H and Han, Q and Zhou, X and Zhang, K and Wang, S and Xu, HHK and Weir, MD and Feng, M and Li, M and Peng, X and Ren, B and Cheng, L}, title = {Heat-Polymerized Resin Containing Dimethylaminododecyl Methacrylate Inhibits Candida albicans Biofilm.}, journal = {Materials (Basel, Switzerland)}, volume = {10}, number = {4}, pages = {}, pmid = {28772791}, issn = {1996-1944}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, abstract = {The prevalence of stomatitis, especially caused by Candida albicans, has highlighted the need of new antifungal denture materials. This study aimed to develop an antifungal heat-curing resin containing quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and evaluate its physical performance and antifungal properties. The discs were prepared by incorporating DMADDM into the polymer liquid of a methyl methacrylate-based, heat-polymerizing resin at 0% (control), 5%, 10%, and 20% (w/w). Flexure strength, bond quality, surface charge density, and surface roughness were measured to evaluate the physical properties of resin. The specimens were incubated with C. albicans solution in medium to form biofilms. Then Colony-Forming Units, XTT assay, and scanning electron microscope were used to evaluate antifungal effect of DMADDM-modified resin. DMADDM modified acrylic resin had no effect on the flexural strength, bond quality, and surface roughness, but it increased the surface charge density significantly. Meanwhile, this new resin inhibited the C. albicans biofilm significantly according to the XTT assay and CFU counting. The hyphae in C. albicans biofilm also reduced in DMADDM-containing groups observed by SEM. DMADDM modified acrylic resin was effective in the inhibition of C. albicans biofilm with good physical properties.}, } @article {pmid28772615, year = {2017}, author = {Li, L and Li, S and Qu, Q and Zuo, L and He, Y and Zhu, B and Li, C}, title = {Streptococcus Sanguis Biofilm Architecture and Its Influence on Titanium Corrosion in Enriched Artificial Saliva.}, journal = {Materials (Basel, Switzerland)}, volume = {10}, number = {3}, pages = {}, pmid = {28772615}, issn = {1996-1944}, abstract = {Bacteria biofilm formation on metals is well-known, while biofilm architecture varies under different conditions. To date, few studies have determined the possible contribution to corrosion of titanium made by biofilm architecture. We investigated the interaction between the oral Streptococcus sanguis biofilm architecture and its influence on titanium corrosion in enriched artificial saliva using electrochemical methods and microscopic study. Patchy biofilms were observed on titanium surface after being immersed in solution containing S. sanguis. The thickness and size of the patchy biofilms increased with an increase of immersion time. The extensive pits were clearly observed by scanning electron microscopy, showing that adsorption of S. sanguis on titanium promoted the localized corrosion. The electrochemical results indicated that the corrosion rates were clearly accelerated in the presence of S. sanguis. The low icorr and high Rt in the first 48 h indicated that a typical passive behavior still remained. Our study showed that the pitting corrosion of titanium was mainly attributed to the formation of a self-catalytic corrosion cell by the co-effect of patchy biofilm and organic acid secreted by S. sanguis.}, } @article {pmid28772391, year = {2017}, author = {Ge, Y and Ren, B and Zhou, X and Xu, HHK and Wang, S and Li, M and Weir, MD and Feng, M and Cheng, L}, title = {Novel Dental Adhesive with Biofilm-Regulating and Remineralization Capabilities.}, journal = {Materials (Basel, Switzerland)}, volume = {10}, number = {1}, pages = {}, pmid = {28772391}, issn = {1996-1944}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, abstract = {The mechanical properties and anti-caries effect of a novel anti-caries adhesive containing poly (amidoamine) dendrimer (PAMAM) and dimethylaminododecyl methacrylate (DMADDM) were investigated for the first time. Microtensile bond strength and surface charge density were measured for the novel anti-caries adhesives. Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii were chosen to form three-species biofilms. Lactic acid assay, MTT (3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, exopolysaccharide staining and live/dead staining were performed to study anti-biofilm effect of the adhesive. The TaqMan realtime polymerase chain reaction was used to study the proportion change in three-species biofilms of different groups. The Scanning Electron Microscope (SEM) was used to observe the remineralization effect of PAMAM and DMADDM. The results showed that incorporating PAMAM and DMADDM into adhesive had no adverse effect on the dentin bond strength. The 1% PAMAM and 5% DMADDM adhesive group showed anti-biofilm properties and developed a healthier biofilm with a lower chance of inducing dental caries. Combination of 1% PAMAM and 5% DMADDM solution maintained remineralization capability on dentin, similar to that using 1% PAMAM alone. In conclusion, the adhesive containing PAMAM and DMADDM had strong antimicrobial properties and biological remineralization capabilities, and is promising for anti-caries clinical applications.}, } @article {pmid28772238, year = {2017}, author = {Ishwarya, R and Vaseeharan, B and Anuradha, R and Rekha, R and Govindarajan, M and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Benelli, G}, title = {Eco-friendly fabrication of Ag nanostructures using the seed extract of Pedalium murex, an ancient Indian medicinal plant: Histopathological effects on the Zika virus vector Aedes aegypti and inhibition of biofilm-forming pathogenic bacteria.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {174}, number = {}, pages = {133-143}, doi = {10.1016/j.jphotobiol.2017.07.026}, pmid = {28772238}, issn = {1873-2682}, mesh = {Aedes/*cytology ; Animals ; Bacteria/*drug effects ; Biofilms/*drug effects ; Green Chemistry Technology ; Insect Vectors/drug effects ; Insecticides/chemistry/pharmacology ; Larva/cytology ; Metal Nanoparticles ; Pedaliaceae/*chemistry ; Plant Extracts/chemistry ; Plants, Medicinal/chemistry ; Seeds/chemistry ; Silver/*chemistry/*pharmacology ; *Zika Virus ; }, abstract = {The control of Zika virus mosquito vectors and well as the development of drugs in the fight against biofilm-forming microbial pathogens, are timely and important challenges in current bionanoscience. Here we focused on the eco-friendly fabrication of Ag nanostructures using the seed extract of Pedalium murex, an ancient Indian medicinal plant. Initial confirmation of Ag nanoparticles (AgNPs) production was showed by a color change from transparent to dark brown. The UV-Visible spectrum (476nm), X-ray diffraction peaks (101, 200, 220 and 311) and Fourier transform infrared spectroscopy shed light on the production of green-capped AgNPs. Morphological structure analysis using HR-TEM showed that the AgNPs were mostly hexagonal in shape with rough edges, and a size of 20-30nm. The larvicidal potential of P. murex seed extract and AgNPs fabricated using the P. murex seed extract (Pm-AgNPs) was tested on fourth instar mosquito larvae of the Zika virus vector Aedes aegypti. Maximum efficacy was achieved by Pm-AgNPs against Ae. aegypti after 24h (LC50 34.88; LC90 64.56mg/ml), if compared to the P. murex seed extract. Histopathological analyses showed severe damages to the hindgut and larval muscles in NPs-treated Ae. aegypti larvae. The sub-MIC concentrations of Pm-AgNPs exhibited significant anti-biofilm activity against Gram positive (Enterococcus faecalis, Staphylococcus aureus) and Gram negative (Shigella sonnei, Pseudomonas aeruginosa) bacterial pathogens, as showed by EPS and MTP assays. Light and CLSM microscopic studies highlighted a significant impact of P. murex seed extract and Pm-synthesized AgNPs on the surface topography and architecture of bacterial biofilm, both in Gram positive and Gram negative species. Overall, results reported here contribute to the development of reliable large-scale protocols for the green fabrication of effective mosquito larvicides and biofilm inhibitors.}, } @article {pmid28771954, year = {2017}, author = {Gusnaniar, N and Sjollema, J and Jong, ED and Woudstra, W and de Vries, J and Nuryastuti, T and van der Mei, HC and Busscher, HJ}, title = {Influence of biofilm lubricity on shear-induced transmission of staphylococcal biofilms from stainless steel to silicone rubber.}, journal = {Microbial biotechnology}, volume = {10}, number = {6}, pages = {1744-1752}, pmid = {28771954}, issn = {1751-7915}, mesh = {Bacterial Adhesion ; *Biofilms ; Silicone Elastomers/*chemistry ; Stainless Steel/*chemistry ; Staphylococcus/chemistry/*physiology ; }, abstract = {In real-life situations, bacteria are often transmitted from biofilms growing on donor surfaces to receiver ones. Bacterial transmission is more complex than adhesion, involving bacterial detachment from donor and subsequent adhesion to receiver surfaces. Here, we describe a new device to study shear-induced bacterial transmission from a (stainless steel) pipe to a (silicone rubber) tube and compare transmission of EPS-producing and non-EPS-producing staphylococci. Transmission of an entire biofilm from the donor to the receiver tube did not occur, indicative of cohesive failure in the biofilm rather than of adhesive failure at the donor-biofilm interface. Biofilm was gradually transmitted over an increasing length of receiver tube, occurring mostly to the first 50 cm of the receiver tube. Under high-shearing velocity, transmission of non-EPS-producing bacteria to the second half decreased non-linearly, likely due to rapid thinning of the lowly lubricious biofilm. Oppositely, transmission of EPS-producing strains to the second tube half was not affected by higher shearing velocity due to the high lubricity and stress relaxation of the EPS-rich biofilms, ensuring continued contact with the receiver. The non-linear decrease of ongoing bacterial transmission under high-shearing velocity is new and of relevance in for instance, high-speed food slicers and food packaging.}, } @article {pmid28771901, year = {2017}, author = {Maiti, K and Syal, K and Chatterji, D and Jayaraman, N}, title = {Synthetic Arabinomannan Heptasaccharide Glycolipids Inhibit Biofilm Growth and Augment Isoniazid Effects in Mycobacterium smegmatis.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {18}, number = {19}, pages = {1959-1970}, doi = {10.1002/cbic.201700247}, pmid = {28771901}, issn = {1439-7633}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/*growth & development ; Dose-Response Relationship, Drug ; Glycolipids/chemical synthesis/chemistry/*pharmacology ; Isoniazid/chemistry/*pharmacology ; Mannans/*chemistry ; Microbial Sensitivity Tests ; Molecular Structure ; Mycobacterium smegmatis/*drug effects/metabolism ; Oligosaccharides/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Biofilm formation, involving attachment to an adherent surface, is a critical survival strategy of mycobacterial colonies in hostile environmental conditions. Here we report the synthesis of heptasaccharide glycolipids based on mannopyranoside units anchored on to a branched arabinofuranoside core. Two types of glycolipids-2,3-branched and 2,5-branched-were synthesized and evaluated for their efficacies in inhibiting biofilm growth by the non-pathogenic mycobacterium variant Mycobacterium smegmatis. Biofilm formation was inhibited at a minimum biofilm growth inhibition concentration (MBIC) of 100 μg mL[-1] in the case of the 2,5-branched heptasaccharide glycolipid. Further, we were able to ascertain that a combination of the drug isoniazid with the branched heptasaccharide glycolipid (50 μg mL[-1]) potentiates the drug, making it three times more effective, with an improved MBIC of 30 μg mL[-1] . These studies establish that synthetic glycolipids not only act as inhibitors of biofilm growth, but also provide a synergistic effect when combined with significantly lowered concentrations of isoniazid to disrupt the biofilm structures of the mycobacteria.}, } @article {pmid28771593, year = {2017}, author = {Taylor, PK and Van Kessel, ATM and Colavita, A and Hancock, REW and Mah, TF}, title = {A novel small RNA is important for biofilm formation and pathogenicity in Pseudomonas aeruginosa.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0182582}, pmid = {28771593}, issn = {1932-6203}, mesh = {Animals ; Biofilms ; Caenorhabditis elegans/*microbiology ; Gene Expression Regulation, Bacterial ; Pseudomonas Infections/mortality ; Pseudomonas aeruginosa/genetics/*growth & development/pathogenicity ; RNA, Bacterial/genetics ; RNA, Small Untranslated/*genetics ; Sequence Analysis, RNA ; *Up-Regulation ; Virulence ; }, abstract = {The regulation of biofilm development requires multiple mechanisms and pathways, but it is not fully understood how these are integrated. Small RNA post-transcriptional regulators are a strong candidate as a regulatory mechanism of biofilm formation. More than 200 small RNAs in the P. aeruginosa genome have been characterized in the literature to date; however, little is known about their biological roles in the cell. Here we describe the identification of the novel regulatory small RNA, SrbA. This locus was up-regulated 45-fold in P. aeruginosa strain PA14 biofilm cultures. Loss of SrbA expression in a deletion strain resulted in a 66% reduction in biofilm mass. Furthermore, the mortality rate over 72 hours in C. elegans infections was reduced to 39% when infected with the srbA deletion strain compared to 78% mortality when infected with the parental wild-type P. aeruginosa strain. There was no significant effect on culture growth or adherence to surfaces with loss of SrbA expression. Also loss of SrbA expression had no effect on antibiotic resistance to ciprofloxacin, gentamicin, and tobramycin. We conclude that SrbA is important for biofilm formation and full pathogenicity of P. aeruginosa.}, } @article {pmid28771501, year = {2017}, author = {Qayyum, S and Oves, M and Khan, AU}, title = {Obliteration of bacterial growth and biofilm through ROS generation by facilely synthesized green silver nanoparticles.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0181363}, pmid = {28771501}, issn = {1932-6203}, mesh = {Bacteria/*drug effects/*growth & development/metabolism ; Biofilms/*drug effects ; DNA Cleavage/drug effects ; Green Chemistry Technology ; HeLa Cells ; Humans ; *Metal Nanoparticles ; Nanotechnology ; Particle Size ; Reactive Oxygen Species/*metabolism ; Silver/*chemistry/*pharmacology/toxicity ; }, abstract = {Mangifera indica inflorescence aqueous extract was utilized for production of green AgNPs. Synthesized AgNPs were characterized by UV-vis spectrophotometry, XRD, TEM, FESEM and particles size analyzer. AgNPs showed minimum inhibitory concentrations (MICs) of 8 μg ml-1 and 16 μg ml-1 for Gram negative (K. pneumoniae, P. aeruginosa and E. coli) and Gram positive (S. mutans and S. aureus) strains, respectively which was relatively quite low compared to chemically synthesized silver nanoparticles. AgNPs inhibited 80% and 75% biofilms of E. coli and S. mutans respectively as observed quantitatively by crystal violet assay. Qualitative biofilm inhibition was observed using SEM and CLSM. AgNPs adsorbed catheter also resisted the growth of biofilm on its surface displaying its possible future applications. AgNPs interaction with bacteria lead to bacterial membrane damage as observed by SEM and TEM. The membrane damage was confirmed by detecting leakage of proteins and reducing sugars from treated bacterial cells. AgNPs generated ROS on interaction with bacterial cells and this ROS production can be one of the possible reasons for their action. AgNPs exhibited no toxic effect on the cell viability of HeLa cell line.}, } @article {pmid28770446, year = {2017}, author = {Berlanga, M and Gomez-Perez, L and Guerrero, R}, title = {Biofilm formation and antibiotic susceptibility in dispersed cells versus planktonic cells from clinical, industry and environmental origins.}, journal = {Antonie van Leeuwenhoek}, volume = {110}, number = {12}, pages = {1691-1704}, doi = {10.1007/s10482-017-0919-2}, pmid = {28770446}, issn = {1572-9699}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion ; Biofilms/*growth & development ; *Environmental Microbiology ; Humans ; Microbial Sensitivity Tests ; Plankton/*drug effects/*physiology ; }, abstract = {We examined the cell-surface physicochemical properties, the biofilm formation capability and the antibiotic susceptibility in dispersed cells (from an artificial biofilm of alginate beads) and compared with their planktonic (free-swimming) counterparts. The strains used were from different origins, such as clinical (Acinetobacter baumannii AB4), cosmetic industry (Klebsiella oxytoca EU213, Pseudomonas aeruginosa EU190), and environmental (Halomonas venusta MAT28). In general, dispersed cells adhered better to surfaces (measured as the "biofilm index") and had a greater hydrophobicity [measured as the microbial affinity to solvents (MATS)] than planktonic cells. The susceptibility to two antibiotics (ciprofloxacin and tetracycline) of dispersed cells was higher compared with that of their planktonic counterparts (tested by the "bactericidal index"). Dispersed and planktonic cells exhibited differences in cell permeability, especially in efflux pump activity, which could be related to the differences observed in susceptibility to antibiotics. At 1 h of biofilm formation in microtiter plates, dispersed cells treated with therapeutic concentration of ciprofloxacin yielded a lower biofilm index than the control dispersed cells without ciprofloxacin. With respect to the planktonic cells, the biofilm index was similar with and without the ciprofloxacin treatment. In both cases there were a reduction of the number of bacteria measured as viable count of the supernatant. The lower biofilm formation in dispersed cells with ciprofloxacin treatment may be due to a significant increase of biofilm disruption with respect to the biofilm from planktonic cells. From a clinical point of view, biofilms formed on medical devices such as catheters, cells that can be related to an infection were the dispersed cells. Our results showed that early treatment with ciprofloxacin of dispersed cells could diminishe bacterial dispersion and facilitate the partial elimination of the new biofilm formed.}, } @article {pmid28769037, year = {2017}, author = {Smolentseva, O and Gusarov, I and Gautier, L and Shamovsky, I and DeFrancesco, AS and Losick, R and Nudler, E}, title = {Mechanism of biofilm-mediated stress resistance and lifespan extension in C. elegans.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {7137}, pmid = {28769037}, issn = {2045-2322}, support = {R01 GM018568/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Adaptation, Biological/genetics ; Animal Feed ; Animals ; *Biofilms ; Biomarkers ; Caenorhabditis elegans/*microbiology/*physiology ; HSP70 Heat-Shock Proteins/genetics/metabolism ; Host-Pathogen Interactions ; Intestinal Mucosa/metabolism/microbiology ; *Longevity ; *Stress, Physiological ; Symbiosis ; }, abstract = {Bacteria naturally form communities of cells known as biofilms. However the physiological roles of biofilms produced by non-pathogenic microbiota remain largely unknown. To assess the impact of a biofilm on host physiology we explored the effect of several non-pathogenic biofilm-forming bacteria on Caenorhabditis elegans. We show that biofilm formation by Bacillus subtilis, Lactobacillus rhamnosus and Pseudomonas fluorescens induces C. elegans stress resistance. Biofilm also protects against pathogenic infection and prolongs lifespan. Total mRNA analysis identified a set of host genes that are upregulated in response to biofilm formation by B. subtilis. We further demonstrate that mtl-1 is responsible for the biofilm-mediated increase in oxidative stress resistance and lifespan extension. Induction of mtl-1 and hsp-70 promotes biofilm-mediated thermotolerance. ilys-2 activity accounts for biofilm-mediated resistance to Pseudomonas aeruginosa killing. These results reveal the importance of non-pathogenic biofilms for host physiology and provide a framework to study commensal biofilms in higher organisms.}, } @article {pmid28768722, year = {2017}, author = {Tynan, A and Mawhinney, L and Armstrong, ME and O'Reilly, C and Kennedy, S and Caraher, E and Jülicher, K and O'Dwyer, D and Maher, L and Schaffer, K and Fabre, A and McKone, EF and Leng, L and Bucala, R and Bernhagen, J and Cooke, G and Donnelly, SC}, title = {Macrophage migration inhibitory factor enhances Pseudomonas aeruginosa biofilm formation, potentially contributing to cystic fibrosis pathogenesis.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {31}, number = {11}, pages = {5102-5110}, pmid = {28768722}, issn = {1530-6860}, support = {R01 HL130669/HL/NHLBI NIH HHS/United States ; }, mesh = {Animals ; Biofilms/growth & development ; Cystic Fibrosis/drug therapy/*metabolism/microbiology ; Disease Models, Animal ; Intramolecular Oxidoreductases/*metabolism/pharmacology ; Macrophage Migration-Inhibitory Factors/*metabolism/pharmacology ; Mice ; Pseudomonas aeruginosa/*physiology ; Recombinant Proteins/pharmacology ; Tobramycin/pharmacology ; }, abstract = {Macrophage migration inhibitory factor (MIF) is a key proinflammatory mediator that we have previously shown to be associated with an aggressive clinical phenotype in cystic fibrosis. It possesses unique tautomerase enzymatic activity. However, to date, no human-derived substrate has been identified that has the capacity to interact with this cytokine's unique tautomerase activity. This led us to hypothesize that MIF may have the capacity to interact with external substrates. We describe for the first time how Pseudomonas aeruginosa can utilize human recombinant MIF (rMIF) to significantly (P < 0.01) enhance its endogenous biofilm formation. Our in vivo studies demonstrate that utilizing a small-molecular-weight inhibitor targeting MIF's tautomerase activity (SCD-19) significantly reduces the inflammatory response in a murine pulmonary chronic P. aeruginosa model. In addition, we show that in in vitro experiments, pretreatment of P. aeruginosa with rMIF is associated with reduced bacterial killing by tobramycin. Our novel findings support the concept of an anti-MIF strategy that targets this enzymatic activity as a potential future antibacterial therapeutic approach.-Tynan, A., Mawhinney, L., Armstrong, M. E., O'Reilly, C., Kennedy, S., Caraher, E., Jülicher, K., O'Dwyer, D., Maher, L., Schaffer, K., Fabre, A., McKone, E. F., Leng, L., Bucala, R., Bernhagen, J., Cooke, G., Donnelly, S. C. Macrophage migration inhibitory factor enhances Pseudomonas aeruginosa biofilm formation, potentially contributing to cystic fibrosis pathogenesis.}, } @article {pmid28764931, year = {2018}, author = {Bravo, Z and Chapartegui-González, I and Lázaro-Díez, M and Ramos-Vivas, J}, title = {Acinetobacter pittii biofilm formation on inanimate surfaces after long-term desiccation.}, journal = {The Journal of hospital infection}, volume = {98}, number = {1}, pages = {74-82}, doi = {10.1016/j.jhin.2017.07.031}, pmid = {28764931}, issn = {1532-2939}, mesh = {Acinetobacter/*physiology ; Biofilms/*growth & development ; *Dehydration ; *Environmental Microbiology ; Humans ; *Microbial Viability ; Time Factors ; }, abstract = {BACKGROUND: The survival of pathogenic micro-organisms in the healthcare environment has a major role in nosocomial infections. Among the responsible mechanisms enabling nosocomial pathogens to persist with these stress conditions is their ability to resist desiccation and to form biofilms.

AIM: To investigate the survival behaviour of Acinetobacter pittii isolates on inert surfaces and saline microcosms.

METHODS: Five A. pittii clinical strains were spotted over white laboratory coat fragments, glass, and plastic surfaces, or inoculated into sterile saline and monitored at room temperature for a period of 43 days.

FINDINGS: Although the permanence on solid surfaces negatively affected the culturability of the strains used, a fraction of stressed cells survived for at least the period of study. On average, A. pittii culturability was reduced by 77.3%, 80.9%, and 68.1% in white coat, plastic, and glass surfaces, respectively. However, ∼85.6% of the populations retain their culturability in saline solution. Culturability correlated with the presence of cells with an intact membrane, as demonstrated after live/dead staining. Supplementation of the culture medium with sodium pyruvate favoured the culturability of strains from all conditions; but, in general, A. pittii populations did not enter a viable but non-culturable state.

CONCLUSION: After long-term desiccation, all A. pittii strains retained, or even increased, their ability to form biofilms after they had been fed with nutrient media. This suggests that A. pittii may recover easily from desiccation and may express adherence factors to infect new hosts after rehydration.}, } @article {pmid28763494, year = {2017}, author = {Álvarez-Fraga, L and Rumbo-Feal, S and Pérez, A and Gómez, MJ and Gayoso, C and Vallejo, JA and Ohneck, EJ and Valle, J and Actis, LA and Beceiro, A and Bou, G and Poza, M}, title = {Global assessment of small RNAs reveals a non-coding transcript involved in biofilm formation and attachment in Acinetobacter baumannii ATCC 17978.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0182084}, pmid = {28763494}, issn = {1932-6203}, mesh = {A549 Cells ; Acinetobacter baumannii/*genetics/physiology ; *Biofilms ; Cell Line, Tumor ; DNA, Complementary/genetics ; *Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Humans ; Microscopy, Electron, Scanning ; RNA, Bacterial/genetics ; RNA, Small Untranslated/*genetics ; Virulence ; }, abstract = {Many strains of Acinetobacter baumannii have been described as being able to form biofilm. Small non-coding RNAs (sRNAs) control gene expression in many regulatory circuits in bacteria. The aim of the present work was to provide a global description of the sRNAs produced both by planktonic and biofilm-associated (sessile) cells of A. baumannii ATCC 17978, and to compare the corresponding gene expression profiles to identify sRNAs molecules associated to biofilm formation and virulence. sRNA was extracted from both planktonic and sessile cells and reverse transcribed. cDNA was subjected to 454-pyrosequencing using the GS-FLX Titanium chemistry. The global analysis of the small RNA transcriptome revealed different sRNA expression patterns in planktonic and biofilm associated cells, with some of the transcripts only expressed or repressed in sessile bacteria. A total of 255 sRNAs were detected, with 185 of them differentially expressed in the different types of cells. A total of 9 sRNAs were expressed only in biofilm cells, while the expression of other 21 coding regions were repressed only in biofilm cells. Strikingly, the expression level of the sRNA 13573 was 120 times higher in biofilms than in planktonic cells, an observation that prompted us to further investigate the biological role of this non-coding transcript. Analyses of an isogenic mutant and over-expressing strains revealed that the sRNA 13573 gene is involved in biofilm formation and attachment to A549 human alveolar epithelial cells. The present work serves as a basis for future studies examining the complex regulatory network that regulate biofilm biogenesis and attachment to eukaryotic cells in A. baumannii ATCC 17978.}, } @article {pmid28762063, year = {2017}, author = {Naik, MM and Bhangui, P and Bhat, C}, title = {The first report on Listeria monocytogenes producing siderophores and responds positively to N-acyl homoserine lactone (AHL) molecules by enhanced biofilm formation.}, journal = {Archives of microbiology}, volume = {199}, number = {10}, pages = {1409-1415}, doi = {10.1007/s00203-017-1416-8}, pmid = {28762063}, issn = {1432-072X}, mesh = {4-Butyrolactone/*analogs & derivatives/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Dairying ; Humans ; *Listeria monocytogenes/classification/genetics/metabolism ; Microbial Sensitivity Tests ; RNA, Ribosomal, 16S/genetics ; Siderophores/*biosynthesis ; Thiazolidines/pharmacology ; }, abstract = {Listeria monocytogenes are Gram-positive well-known emerging food-borne pathogens causing listeriosis in humans. In the present study, we have isolated biofilm-forming Listeria sp. from utensils used by a local milk collection dairy society at Usgao Goa, which collects milk for Goa dairy. Through biochemical tests and 16S rRNA sequence analysis, the bacterium was confirmed to be L. monocytogenes and designated as strain BN3, having GenBank accession number MF095110. We report for the first time Gram-positive L. monocytogenes strain BN3 producing iron-chelating siderophores by chrome azurol S (CAS) agar test. Also, this is a first report which reveals that L. monocytogenes strain BN3 responds to N-hexanoyl-homoserine lactone molecule (C6-HSL) by gradual increase in their biofilm-forming potential with a gradual increase in AHL (C6-HSL) concentration (250, 500 nM-1 μM) as compared to control revealed by crystal violet assay (CV) in microtiter plate. These results were further confirmed by scanning electron microscopy (SEM). A significant decrease in biofilm formation was observed when L. monocytogenes strain BN3 was treated with 10 µg/ml (R)-2-(2-hydroxynaphthalen-1-yl)thiazolidine-4-carboxylic acid, but when 250 and 500 nM AHL molecules were added, biofilm formation in strain BN3 was found to be enhanced as compared to control even in the presence of antibacterial compound, (R)-2-(2-hydroxynaphthalen-1-yl)thiazolidine-4-carboxylic acid. These results revealed that AHL molecules nullify the effect of antimicrobial compound and promote biofilm formation in L. monocytogenes strain BN3.}, } @article {pmid28761244, year = {2017}, author = {Shajahan, IF and Kandaswamy, D and Lakshminarayanan, L and Selvarajan, R}, title = {Substantivity of hypochlorous acid-based disinfectant against biofilm formation in the dental unit waterlines.}, journal = {Journal of conservative dentistry : JCD}, volume = {20}, number = {1}, pages = {2-5}, pmid = {28761244}, issn = {0972-0707}, abstract = {OBJECTIVE: The purpose of the study was to examine the substantivity of a new disinfectant against biofilm formation in the dental unit waterlines.

MATERIALS AND METHODS: Twenty dental units were selected for the study and divided into two groups: Group A (dental unit waterlines treated with the disinfectant) and Group B (untreated dental unit waterlines). Biofilm formation was monitored in both groups by removing the one dental unit waterline from each group for the period of 10 days. One inch of the dental unit waterline tube was cut at random site, and the inner lumen of the cut sections was analyzed using the scanning electron microscope (SEM) (TESCAN VEGA3 SBU).

RESULTS: On examination, SEM images showed that there was no slime layer or bacterial cells seen in cut section for the period of 7 days in the treated dental waterlines, which means that there is no evident of biofilm formation. In the untreated dental unit waterline cut section, slime layer was observed from day 1.

CONCLUSION: Disinfectant solution was proved to be effective for 7 days against biofilm formation. This technique could be used as a valid method for disinfection of dental unit waterlines.}, } @article {pmid28761161, year = {2017}, author = {Jia, R and Yang, D and Xu, D and Gu, T}, title = {Mitigation of a nitrate reducing Pseudomonas aeruginosa biofilm and anaerobic biocorrosion using ciprofloxacin enhanced by D-tyrosine.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {6946}, pmid = {28761161}, issn = {2045-2322}, mesh = {Anaerobiosis ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Corrosion ; Drug Synergism ; Microbial Sensitivity Tests ; Nitrates/metabolism ; Pseudomonas aeruginosa/*drug effects/metabolism/physiology ; Tyrosine/*pharmacology ; }, abstract = {Pseudomonas aeruginosa (PA) is a ubiquitous microbe. It can form recalcitrant biofilms in clinical and industrial settings. PA biofilms cause infections in patients. They also cause biocorrosion of medical implants. In this work, D-tyrosine (D-tyr) was investigated as an antimicrobial enhancer for ciprofloxacin (CIP) against a wild-type PA biofilm (strain PAO1) on C1018 carbon steel in a strictly anaerobic condition. Seven-day biofilm prevention test results demonstrated that 2 ppm (w/w) D-tyr enhanced 30 ppm CIP by achieving extra 2-log sessile cell reduction compared with the 30 ppm CIP alone treatment. The cocktail of 30 ppm CIP + 2 ppm D-tyr achieved similar efficacy as the 80 ppm CIP alone treatment in the biofilm prevention test. Results also indicated that the enhanced antimicrobial treatment reduced weight loss and pitting corrosion. In the 3-hour biofilm removal test, the cocktail of 80 ppm CIP + 5 ppm D-tyr achieved extra 1.5-log reduction in sessile cell count compared with the 80 ppm CIP alone treatment. The cocktail of 80 ppm CIP + 5 ppm D-tyr achieved better efficacy than the 150 ppm CIP alone treatment in the biofilm removal test.}, } @article {pmid28760898, year = {2017}, author = {Roizman, D and Vidaillac, C and Givskov, M and Yang, L}, title = {In Vitro Evaluation of Biofilm Dispersal as a Therapeutic Strategy To Restore Antimicrobial Efficacy.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {10}, pages = {}, pmid = {28760898}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Combinations ; Drug Synergism ; Humans ; Imipenem/*pharmacology ; Microbial Sensitivity Tests ; Phosphoric Diester Hydrolases/metabolism ; Proof of Concept Study ; Pseudomonas aeruginosa/*drug effects/genetics/pathogenicity ; Tobramycin/*pharmacology ; }, abstract = {As a proof-of-concept study, the direct impact of biofilm dispersal on the in vitro efficacy of imipenem and tobramycin was evaluated against 3-day-old biofilms of Pseudomonas aeruginosa Arabinose induction of biofilm dispersal via activation of the phosphodiesterase YhjH in the P. aeruginosa engineered strain PAO1/p BAD -yhjH resulted in increased antimicrobial efficacy and synergy of the imipenem-tobramycin combination. These results support the use of biofilm dispersal to enhance antimicrobial efficacy in the treatment of biofilm-associated infections, representing a promising therapeutic strategy.}, } @article {pmid28760455, year = {2017}, author = {Hashemizadeh, Z and Kalantar-Neyestanaki, D and Mansouri, S}, title = {Association between virulence profile, biofilm formation and phylogenetic groups of Escherichia coli causing urinary tract infection and the commensal gut microbiota: A comparative analysis.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {540-545}, doi = {10.1016/j.micpath.2017.07.046}, pmid = {28760455}, issn = {1096-1208}, mesh = {Biofilms/*growth & development ; Escherichia coli/*classification/genetics/isolation & purification/physiology ; Escherichia coli Infections/*microbiology ; Gastrointestinal Tract/*microbiology ; Genotype ; Hemagglutination ; Hemolysin Proteins/analysis ; Hospitals ; Humans ; Iran ; *Phylogeny ; Urinary Tract Infections/*microbiology ; Virulence Factors/*genetics ; }, abstract = {Variety of virulence factors are involved in the pathogenicity of Escherichia coli, the common cause of the urinary tract infections (UTIs). The aim of this study was to determine some virulence factors involved in the pathogenicity and the phylogenetic grouping of E. coli from UTIs compared with the E. coli isolates from gut microbiota (fecal flora). The isolates were tested for biofilm formation, haemagglutination, cell surface hydrophobicity (CSH), hemolysin production, phylogenetic grouping and the distribution of 6 known virulence genes. Isolates from UTIs showed a significantly higher prevalence of haemagglutination and hemolysin production compared with fecal flora (P ≤ 0.05), while biofilm formation and cell surface hydrophobicity (CSH) were not significantly different among the groups. Prevalence of virulence genes fimH, kpsMT ll, iutA, sat, hlyA, and cnf1 among all isolates were: 94.5%, 66.95%, 67.8%, 39%, 23.07% and 21.08%, respectively. The genes for hlyA, cnf1, kpsMT ll were found to be higher in UTI isolates compared to fecal flora (P ≤ 0.05). The frequency of the isolates in the phylogenetic groups B2, D, A and B1 were 36.7%, 31.3%, 16.2% and 15.6%, respectively. All the virulence genes except fimH were found to be significantly higher in the isolates of groups B2 and D. The results suggests that certain factors are necessary for the host colonization and infection and they are common in both virulent and non-virulent strains, and that the strains in the groups A and B1 having the lower virulence factors must acquire these factors when the condition is in favor of their dissemination to the urinary tract. In contrast the isolates in the groups B2 and D appeared to be potentially virulent.}, } @article {pmid28759795, year = {2017}, author = {Jeong, S and Cho, K and Jeong, D and Lee, S and Leiknes, T and Vigneswaran, S and Bae, H}, title = {Effect of engineered environment on microbial community structure in biofilter and biofilm on reverse osmosis membrane.}, journal = {Water research}, volume = {124}, number = {}, pages = {227-237}, doi = {10.1016/j.watres.2017.07.064}, pmid = {28759795}, issn = {1879-2448}, mesh = {*Biofilms ; Filtration ; Membranes, Artificial ; Osmosis ; *Water Purification ; }, abstract = {Four dual media filters (DMFs) were operated in a biofiltration mode with different engineered environments (DMF I and II: coagulation with/without acidification and DMF III and IV: without/with chlorination). Designed biofilm enrichment reactors (BERs) containing the removable reverse osmosis (RO) coupons, were connected at the end of the DMFs in parallel to analyze the biofilm on the RO membrane by DMF effluents. Filtration performances were evaluated in terms of dissolved organic carbon (DOC) and assimilable organic carbon (AOC). Organic foulants on the RO membrane were also quantified and fractionized. The bacterial community structures in liquid (seawater and effluent) and biofilm (DMF and RO) samples were analyzed using 454-pyrosequencing. The DMF IV fed with the chlorinated seawater demonstrated the highest reductions of DOC including LMW-N as well as AOC among the other DMFs. The DMF IV was also effective in reducing organic foulants on the RO membrane surface. The bacterial community structure was grouped according to the sample phase (i.e., liquid and biofilm samples), sampling location (i.e., DMF and RO samples), and chlorination (chlorinated and non-chlorinated samples). In particular, the biofilm community in the DMF IV differed from the other DMF treatments, suggesting that chlorination exerted as stronger selective pressure than pH adjustment or coagulation on the biofilm community. In the DMF IV, several chemoorganotrophic chlorine-resistant biofilm-forming bacteria such as Hyphomonas, Erythrobacter, and Sphingomonas were predominant, and they may enhance organic carbon degradation efficiency. Diverse halophilic or halotolerant organic degraders were also found in other DMFs (i.e., DMF I, II, and III). Various kinds of dominant biofilm-forming bacteria were also investigated in RO membrane samples; the results provided possible candidates that cause biofouling when DMF process is applied as the pretreatment option for the RO process.}, } @article {pmid28758290, year = {2017}, author = {Wen, Y and Ouyang, Z and Devreese, B and He, W and Shao, Y and Lu, W and Zheng, F}, title = {Crystal structure of master biofilm regulator CsgD regulatory domain reveals an atypical receiver domain.}, journal = {Protein science : a publication of the Protein Society}, volume = {26}, number = {10}, pages = {2073-2082}, pmid = {28758290}, issn = {1469-896X}, mesh = {Bacterial Proteins/*chemistry/*metabolism ; Biofilms ; Crystallography ; Phosphorylation ; Protein Domains ; Salmonella typhimurium/chemistry/metabolism ; Signal Transduction ; Trans-Activators/*chemistry/*metabolism ; }, abstract = {The master regulator CsgD switches planktonic growth to biofilm formation by activating synthesis of curli fimbriae and cellulose in Enterobacteriaceae. CsgD was classified to be the LuxR response regulatory family, while its cognate sensor histidine kinase has not been identified yet. CsgD consists of a C-terminal DNA binding domain and an N-terminal regulatory domain that provokes the upstream signal transduction to further modulate its function. We provide the crystal structure of Salmonella Typhimurium CsgD regulatory domain, which reveals an atypical β5α5 response regulatory receiver domain folding with the α2 helix representing as a disorder loop compared to the LuxR/FixJ canonical response regulator, and the structure indicated a noteworthy α5 helix similar to the non-canonical master regulator VpsT receiver domain α6. CsgD regulatory domain assembles with two dimerization interfaces mainly through α1 and α5, which has shown similarity to the c-di-GMP independent and stabilized dimerization interface of VpsT from Vibrio cholerae respectively. The potential phosphorylation site D59 is directly involved in the interaction of interfaces I and mutagenesis studies indicated that both dimerization interfaces could be crucial for CsgD activity. The structure reveals important molecular details for the dimerization assembly of CsgD and will shed new insight into its regulation mechanism.}, } @article {pmid28758016, year = {2017}, author = {Yoshii, Y and Okuda, KI and Yamada, S and Nagakura, M and Sugimoto, S and Nagano, T and Okabe, T and Kojima, H and Iwamoto, T and Kuwano, K and Mizunoe, Y}, title = {Norgestimate inhibits staphylococcal biofilm formation and resensitizes methicillin-resistant Staphylococcus aureus to β-lactam antibiotics.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {18}, pmid = {28758016}, issn = {2055-5008}, abstract = {Formation of bacterial biofilms on medical devices can cause severe or fatal infectious diseases. In particular, biofilm-associated infections caused by methicillin-resistant Staphylococcus aureus are difficult to eradicate because the biofilm is strongly resistant to antibiotics and the host immune response. There is no effective treatment for biofilm-associated infectionss, except for surgical removal of contaminated medical devices followed by antibiotic therapy. Here we show that norgestimate, an acetylated progestin, effectively inhibits biofilm formation by staphylococcal strains, including methicillin-resistant S. aureus, without inhibiting their growth, decreasing the selective pressure for emergence of resistance. 17-Deacetyl norgestimate, a metabolite of norgestimate, shows much weaker inhibitory activity against staphylococcal biofilm formation, indicating that the acetyl group of norgestimate is important for its activity. Norgestimate inhibits staphylococcal biofilm formation by inhibiting production of polysaccharide intercellular adhesin and proteins in the extracellular matrix. Proteome analysis of S. aureus indicated that norgestimate represses the expression of the cell wall-anchored protein SasG, which promotes intercellular adhesion, and of the glycolytic enzyme enolase, which plays a secondary role in biofilm formation. Notably, norgestimate induces remarkable changes in cell wall morphology, characterized by increased thickness and abnormal rippled septa. Furthermore, norgestimate increases the expression level of penicillin binding protein 2 and resensitizes methicillin-resistant S. aureus to β-lactam antibiotics. These results suggest that norgestimate is a promising lead compound for the development of drugs to treat biofilm-associated infections, as well as for its ability to resensitize methicillin-resistant S. aureus to β-lactam antibiotics.}, } @article {pmid28757274, year = {2017}, author = {Bazari, PAM and Honarmand Jahromy, S and Zare Karizi, S}, title = {Phenotypic and genotypic characterization of biofilm formation among Staphylococcus aureus isolates from clinical specimens, an Atomic Force Microscopic (AFM) study.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {533-539}, doi = {10.1016/j.micpath.2017.07.041}, pmid = {28757274}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/genetics/metabolism ; Biofilms/*growth & development ; Humans ; Iran ; Microscopy, Atomic Force ; Polymerase Chain Reaction ; Polysaccharides, Bacterial/genetics/metabolism ; Staining and Labeling ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*genetics/isolation & purification/*physiology ; }, abstract = {INTRODUCTION: Staphylococcus aureus is a major cause of nosocomial infections. Biofilm formation is an important factor for bacterial pathogenesis. Its mechanisms are complex and include of many genes depends on expression of icaADBC operon involved in the synthesis of a polysaccharide intercellular adhesion.

AIM: The aim of study was to investigate biofilm forming ability of Staphylococcus aureus strains by phenotypic and genotypic methods. Also Atomic Force microscope (AFM) was used to visualize biofilm formation.

METHODS: 140 Isolates were collected from clinical specimens of patients in Milad Hospital, Tehran and diagnosed by biochemical tests. The ability of strains to produce slime was evaluated by CRA method. For diagnosing of bacterial EPS, Indian ink staining were used and finally biofilm surface of 3 isolates observed by AFM. The prevalence of icaA and icaD genes was determined by PCR.

RESULTS: By CRA method 15% of samples considered as positive slime producers, 44.28% as intermediate and 40.71% indicative as negative slime producers. 118 staphylococcus aureus strains showed a distinct halo transparent zone but 22 strains showed no halo zone. AFM analysis of Slime positive isolates showed a distinct and complete biofilm formation. In slime negative strain, there was not observed biofilm. The prevalence of icaA, icaD genes was 44.2% and 10% of the isolates had both genes simultaneously.

CONCLUSION: There is a relationship between exopolysaccharide layer and biofilm formation of Staphylococcus aureus isolates. The presence of icaAD genes among isolates is not associated with in vitro formation of biofilm. AFM is a useful tool for observation of bacterial biofilm formation.}, } @article {pmid28757033, year = {2017}, author = {Isaac, P and Bohl, LP and Breser, ML and Orellano, MS and Conesa, A and Ferrero, MA and Porporatto, C}, title = {Commensal coagulase-negative Staphylococcus from the udder of healthy cows inhibits biofilm formation of mastitis-related pathogens.}, journal = {Veterinary microbiology}, volume = {207}, number = {}, pages = {259-266}, doi = {10.1016/j.vetmic.2017.05.025}, pmid = {28757033}, issn = {1873-2542}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Cell Survival ; Female ; Mammary Glands, Animal/cytology/microbiology ; Mastitis, Bovine/*microbiology ; Milk/microbiology ; Phylogeny ; Staphylococcus/*classification/*physiology ; }, abstract = {Bovine mastitis, considered the most important cause of economic losses in the dairy industry, is a major concern in veterinary medicine. Staphylococcus aureus and coagulase-negative staphylococci (CNS) are the main pathogens associated with intramammary infections, and bacterial biofilms are suspected to be responsible for the persistence of this disease. CNS from the udder are not necessarily associated with intramammary infections. In fact, some commensal CNS have been shown to have biological activities. This issue led us to screen exoproducts from commensal Staphylococcus chromogenes for anti-biofilm activity against different mastitis pathogens. The cell-free supernatant from S. chromogenes LN1 (LN1-CFS) was confirmed to display a non-biocidal inhibition of pathogenic biofilms. The supernatant was subjected to various treatments to estimate the nature of the biofilm-inhibiting compounds. The results showed that the bioactive compound >5KDa in mass is sensitive to thermal treatment and proteinase K digestion, suggesting its protein properties. LN1-CFS was able to significantly inhibit S. aureus and CNS biofilm formation in a dose-independent manner and without affecting the viability of bovine cells. These findings reveal a new activity of the udder microflora of healthy animals. Studies are underway to purify and identify the anti-biofilm biocompound and to evaluate its biological activity in vivo.}, } @article {pmid28756127, year = {2018}, author = {Hui, C and Guo, X and Sun, P and Khan, RA and Zhang, Q and Liang, Y and Zhao, YH}, title = {Removal of nitrite from aqueous solution by Bacillus amyloliquefaciens biofilm adsorption.}, journal = {Bioresource technology}, volume = {248}, number = {Pt B}, pages = {146-152}, doi = {10.1016/j.biortech.2017.06.176}, pmid = {28756127}, issn = {1873-2976}, mesh = {Adsorption ; *Bacillus amyloliquefaciens ; Biofilms ; Hydrogen-Ion Concentration ; Kinetics ; *Nitrites ; Solutions ; Thermodynamics ; *Wastewater ; Water Pollutants, Chemical ; }, abstract = {A newly verified adsorbent biofilm produced by Bacillus amyloliquefaciens DT was investigated for nitrite removal from aqueous solutions. The biofilm's characteristics and adsorption mechanism were determined, with results indicating that nitrite ions were adsorbed onto the protonated amine sites of biofilm under acidic conditions. Analysis of various factors showed that higher nitrite adsorption capacities occurred at pH < 3.0 and higher temperatures as well as higher initial nitrite concentrations, with a maximum nitrite removal capacity of 116.84mg/g. Furthermore, nitrite adsorption was well fitted to the pseudo second-order and Weber-Morris kinetic models, and the Freundlich and Sips isotherm models. Simultaneously, thermodynamic analysis demonstrated that nitrite adsorption is a spontaneous endothermic process. In summary, the adsorption of nitrite was complex, and mainly resulted from electrostatic attraction and intraparticle diffusion. Consequently, the B. amyloliquefaciens biofilm can be considered as a promising adsorbent for nitrite removal from wastewater.}, } @article {pmid28755810, year = {2017}, author = {Guo, XP and Niu, ZS and Lu, DP and Feng, JN and Chen, YR and Tou, FY and Liu, M and Yang, Y}, title = {Bacterial community structure in the intertidal biofilm along the Yangtze Estuary, China.}, journal = {Marine pollution bulletin}, volume = {124}, number = {1}, pages = {314-320}, doi = {10.1016/j.marpolbul.2017.07.051}, pmid = {28755810}, issn = {1879-3363}, mesh = {Bacteria/classification/*genetics/growth & development ; *Biodiversity ; *Biofilms ; China ; Ecology ; *Estuaries ; High-Throughput Nucleotide Sequencing ; Hydrogen-Ion Concentration ; Microbial Consortia/*genetics ; Oxygen ; Proteobacteria/classification/genetics/growth & development ; RNA, Ribosomal, 16S/genetics ; Salinity ; Sequence Analysis, DNA ; }, abstract = {In this study, the 16S rRNA-based Illumina MiSeq sequencing was used to investigate the bacterial community structure and composition of intertidal biofilm taken along the Yangtze Estuary. The results showed that 680,721 valid sequences of seven samples were assigned to 147,239 operational taxonomic units, which belonged to 49 phyla, 246 family and 314 genera. Compared to other studies on water and sediments in the study area, biofilms showed highest index of bacterial diversity and abundances. At different taxonomic levels, both dominant taxa and their abundances varied among the seven samples, with Proteobacteria as the dominant phylum in general. Principal component analysis and cluster analysis revealed that bacterial communities at WSK differed from those at other sampling sites. Salinity, dissolved oxygen, pH and nutrients were the vital environmental factors to influence the bacterial community structure of biofilms. These results may provide a new insight into the microbial ecology in estuarine environments.}, } @article {pmid28755486, year = {2017}, author = {Herrling, MP and Weisbrodt, J and Kirkland, CM and Williamson, NH and Lackner, S and Codd, SL and Seymour, JD and Guthausen, G and Horn, H}, title = {NMR investigation of water diffusion in different biofilm structures.}, journal = {Biotechnology and bioengineering}, volume = {114}, number = {12}, pages = {2857-2867}, doi = {10.1002/bit.26392}, pmid = {28755486}, issn = {1097-0290}, mesh = {Absorption, Physiological ; Bacteria/*chemistry ; *Biofilms ; Computer Simulation ; Diffusion ; Magnetic Resonance Spectroscopy/*methods ; *Models, Biological ; *Models, Chemical ; Water/*chemistry ; }, abstract = {Mass transfer in biofilms is determined by diffusion. Different mostly invasive approaches have been used to measure diffusion coefficients in biofilms, however, data on heterogeneous biomass under realistic conditions is still missing. To non-invasively elucidate fluid-structure interactions in complex multispecies biofilms pulsed field gradient-nuclear magnetic resonance (PFG-NMR) was applied to measure the water diffusion in five different types of biomass aggregates: one type of sludge flocs, two types of biofilm, and two types of granules. Data analysis is an important issue when measuring heterogeneous systems and is shown to significantly influence the interpretation and understanding of water diffusion. With respect to numerical reproducibility and physico-chemical interpretation, different data processing methods were explored: (bi)-exponential data analysis and the Γ distribution model. Furthermore, the diffusion coefficient distribution in relation to relaxation was studied by D-T2 maps obtained by 2D inverse Laplace transform (2D ILT). The results show that the effective diffusion coefficients for all biofilm samples ranged from 0.36 to 0.96 relative to that of water. NMR diffusion was linked to biofilm structure (e.g., biomass density, organic and inorganic matter) as observed by magnetic resonance imaging and to traditional biofilm parameters: diffusion was most restricted in granules with compact structures, and fast diffusion was found in heterotrophic biofilms with fluffy structures. The effective diffusion coefficients in the biomass were found to be broadly distributed because of internal biomass heterogeneities, such as gas bubbles, precipitates, and locally changing biofilm densities. Thus, estimations based on biofilm bulk properties in multispecies systems can be overestimated and mean diffusion coefficients might not be sufficiently informative to describe mass transport in biofilms and the near bulk.}, } @article {pmid28754382, year = {2017}, author = {Even, C and Marlière, C and Ghigo, JM and Allain, JM and Marcellan, A and Raspaud, E}, title = {Recent advances in studying single bacteria and biofilm mechanics.}, journal = {Advances in colloid and interface science}, volume = {247}, number = {}, pages = {573-588}, doi = {10.1016/j.cis.2017.07.026}, pmid = {28754382}, issn = {1873-3727}, mesh = {Bacillus subtilis/*chemistry ; Bacterial Adhesion ; Biofilms/*growth & development ; Biomechanical Phenomena ; Cell Wall/chemistry ; Escherichia coli/*chemistry ; Fimbriae, Bacterial/chemistry ; Hydrogels/chemistry ; Mechanotransduction, Cellular/*physiology ; Single-Cell Analysis ; Staphylococcus aureus/*chemistry ; Thermodynamics ; }, abstract = {Bacterial biofilms correspond to surface-associated bacterial communities embedded in hydrogel-like matrix, in which high cell density, reduced diffusion and physico-chemical heterogeneity play a protective role and induce novel behaviors. In this review, we present recent advances on the understanding of how bacterial mechanical properties, from single cell to high-cell density community, determine biofilm tri-dimensional growth and eventual dispersion and we attempt to draw a parallel between these properties and the mechanical properties of other well-studied hydrogels and living systems.}, } @article {pmid28753997, year = {2017}, author = {Yan, H and Yang, H and Li, K and Yu, J and Huang, C}, title = {Effects of Chlorhexidine-Encapsulated Mesoporous Silica Nanoparticles on the Anti-Biofilm and Mechanical Properties of Glass Ionomer Cement.}, journal = {Molecules (Basel, Switzerland)}, volume = {22}, number = {7}, pages = {}, pmid = {28753997}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/*chemistry ; Biofilms/*drug effects ; Chlorhexidine/*chemistry/*pharmacology ; Glass Ionomer Cements/*chemistry ; Hardness ; Materials Testing/methods ; Nanoparticles/*chemistry ; Silicon Dioxide/*chemistry ; Surface Properties ; }, abstract = {One of the primary causes for the failure of glass ionomer cement (GIC) is secondary caries. To enhance the anti-microbial performance of GIC without affecting its mechanical properties, chlorhexidine (CHX) was encapsulated in expanded-pore mesoporous silica nanoparticles (pMSN) to synthesize CHX@pMSN. CHX@pMSN was added at three mass fractions (1%, 5%, and 10% (w/w)) to GIC powder as the experimental groups. Pure GIC was set as the control group. The mechanical and anti-biofilm properties of GIC from each group were tested. The results demonstrated that CHX was successfully encapsulated on/into pMSN, and the encapsulating efficiency of CHX was 44.62% in CHX@pMSN. The anti-biofilm ability was significantly enhanced in all experimental groups (p < 0.001) compared with that in the control group. CHX was continuously released, and anti-biofilm ability was maintained up to 30 days. In addition, the mechanical properties (compressive strength, surface hardness, elastic modulus, water sorption, and solubility) of 1% (w/w) group were maintained compared with those in the control group (p > 0.05). In conclusion, adding 1% (w/w) CHX@pMSN to GIC led to conspicuous anti-biofilm ability and had no adverse effect on the mechanical properties of this restorative material. This study proposes a new strategy for preventing secondary caries by using CHX@pMSN-modified GIC.}, } @article {pmid28752304, year = {2017}, author = {Pfendler, S and Einhorn, O and Bousta, F and Khatyr, A and Alaoui-Sossé, L and Aleya, L and Alaoui-Sossé, B}, title = {UV-C as a means to combat biofilm proliferation on prehistoric paintings: evidence from laboratory experiments.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {27}, pages = {21601-21609}, pmid = {28752304}, issn = {1614-7499}, mesh = {Biofilms/*radiation effects ; Caves ; Cyanobacteria ; History, Ancient ; Humans ; Microscopy, Electron, Scanning ; Paint/*radiation effects ; Paintings/*history ; Plants ; *Ultraviolet Rays ; }, abstract = {A laboratory investigation of UV-C effects was conducted over a 62-h period: a much higher dose than in classic UV-C treatment was applied to five pigments and two painting binders used by prehistoric humans. Colorimetric parameters were compared to a control to see if UV-C can change pigment and binder color. Infrared spectroscopy, scanning electron microscopy, inductively coupled plasma and X-ray crystallography were also carried out to confirm colorimetric measurement. In order to understand how microorganism may physically deteriorate paintings, limestone blocks were painted and monitored until their complete colonization by algae, cyanobacteria, fungi and/or mosses. The results show that UV-C has no effect on mineral compounds. Conversely, it is noteworthy that binder color changed under both UV-C light conditions as well as in visible light. Concerning painted blocks, a fast proliferation has been observed with deterioration of the paintings. These results show the high importance of treating biofilm as soon as possible. Moreover, these findings may be a promising avenue inducing cave managers to use friendly UV-C light to treat contaminated cave paintings and also in the prevention of biodeterioration by lampenflora.}, } @article {pmid28752078, year = {2017}, author = {Uppuluri, P and Busscher, HJ and Chakladar, J and van der Mei, HC and Chaffin, WL}, title = {Transcriptional Profiling of C. albicans in a Two Species Biofilm with Rothia dentocariosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {311}, pmid = {28752078}, issn = {2235-2988}, support = {R01 DE014029/DE/NIDCR NIH HHS/United States ; UL1 TR000124/TR/NCATS NIH HHS/United States ; UL1 TR001881/TR/NCATS NIH HHS/United States ; }, mesh = {*Biofilms ; Candida/genetics/growth & development/metabolism ; Candida albicans/*genetics/growth & development/physiology ; Fungal Proteins/*genetics/metabolism ; Gene Expression Profiling ; Hyphae/genetics/growth & development/metabolism ; Micrococcaceae/genetics/*physiology ; }, abstract = {Biofilms on silicone rubber voice prostheses are the major cause for frequent failure and replacement of these devices. The presence of both bacterial and yeast strains has been suggested to be crucial for the development of voice prosthetic biofilms. Polymicrobial biofilms that include Candida albicans and Rothia dentocariosa are the leading cause of voice prosthesis failure. An in vitro biofilm comprising these two organisms was developed on silicone rubber, a material used for Groningen button voice prosthesis. We found that this biofilm environment was not conducive for C. albicans growth or differentiation. Global transcriptional analyses of C. albicans biofilm cells grown with R. dentocariosa revealed that genes with functions related to cell cycle progression and hyphal development were repressed >2-fold. The mixed species biofilms were more compact and less robust compared to C. albicans mono-species biofilms, even when developed under conditions of continuous nutrient flow. Under these conditions R. dentocariosa also significantly inhibited C. albicans biofilm dispersal. Preferential adherence of R. dentocariosa to candidal hyphae was mediated by the adhesin Als3.}, } @article {pmid28751732, year = {2017}, author = {Morris, RJ and Schor, M and Gillespie, RMC and Ferreira, AS and Baldauf, L and Earl, C and Ostrowski, A and Hobley, L and Bromley, KM and Sukhodub, T and Arnaouteli, S and Stanley-Wall, NR and MacPhee, CE}, title = {Natural variations in the biofilm-associated protein BslA from the genus Bacillus.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {6730}, pmid = {28751732}, issn = {2045-2322}, support = {BB/I019464/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L006804/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Amino Acid Sequence ; Bacillus amyloliquefaciens/*genetics/metabolism ; Bacillus licheniformis/*genetics/metabolism ; Bacillus pumilus/*genetics/metabolism ; Bacillus subtilis/*genetics/metabolism ; Bacterial Proteins/*chemistry/genetics/metabolism ; Biofilms/*growth & development ; Cloning, Molecular ; Elasticity ; Escherichia coli/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Genetic Variation ; Genetic Vectors/chemistry/metabolism ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Phenotype ; Phylogeny ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Recombinant Proteins/chemistry/genetics/metabolism ; Sequence Alignment ; Sequence Homology, Amino Acid ; }, abstract = {BslA is a protein secreted by Bacillus subtilis which forms a hydrophobic film that coats the biofilm surface and renders it water-repellent. We have characterised three orthologues of BslA from Bacillus amyloliquefaciens, Bacillus licheniformis and Bacillus pumilus as well as a paralogue from B. subtilis called YweA. We find that the three orthologous proteins can substitute for BslA in B. subtilis and confer a degree of protection, whereas YweA cannot. The degree to which the proteins functionally substitute for native BslA correlates with their in vitro biophysical properties. Our results demonstrate the use of naturally-evolved variants to provide a framework for teasing out the molecular basis of interfacial self-assembly.}, } @article {pmid28750776, year = {2017}, author = {Cazzaniga, G and Ottobelli, M and Ionescu, AC and Paolone, G and Gherlone, E and Ferracane, JL and Brambilla, E}, title = {In vitro biofilm formation on resin-based composites after different finishing and polishing procedures.}, journal = {Journal of dentistry}, volume = {67}, number = {}, pages = {43-52}, doi = {10.1016/j.jdent.2017.07.012}, pmid = {28750776}, issn = {1879-176X}, mesh = {Aluminum Oxide/chemistry ; Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Bioreactors/microbiology ; Composite Resins/*chemistry ; Dental Materials/*chemistry ; Dental Polishing/*instrumentation/*methods ; Materials Testing ; Nanocomposites/chemistry ; Polyethylene Terephthalates/chemistry ; Streptococcus mutans ; Surface Properties ; Time Factors ; }, abstract = {OBJECTIVES: To evaluate the influence of surface treatments of different resin-based composites (RBCs) on S. mutans biofilm formation.

METHODS: 4 RBCs (microhybrid, nanohybrid, nanofilled, bulk-filled) and 6 finishing-polishing (F/P) procedures (open-air light-curing, light-curing against Mylar strip, aluminum oxide discs, one-step rubber point, diamond bur, multi-blade carbide bur) were evaluated. Surface roughness (SR) (n=5/group), gloss (n=5/group), scanning electron microscopy morphological analysis (SEM), energy-dispersive X-ray spectrometry (EDS) (n=3/group), and S. mutans biofilm formation (n=16/group) were assessed. EDS analysis was repeated after the biofilm assay. A morphological evaluation of S. mutans biofilm was also performed using confocal laser-scanning microscopy (CLSM) (n=2/group). The data were analyzed using Wilcoxon (SR, gloss) and two-way ANOVA with Tukey as post-hoc tests (EDS, biofilm formation).

RESULTS: F/P procedures as well as RBCs significantly influenced SR and gloss. While F/P procedures did not significantly influence S. mutans biofilm formation, a significant influence of RBCs on the same parameter was found. Different RBCs showed different surface elemental composition. Both F/P procedures and S. mutans biofilm formation significantly modified this parameter.

CONCLUSIONS: The tested F/P procedures significantly influenced RBCs surface properties but did not significantly affect S. mutans biofilm formation. The significant influence of the different RBCs tested on S. mutans biofilm formation suggests that material characteristics and composition play a greater role than SR.

CLINICAL SIGNIFICANCE: F/P procedures of RBCs may unexpectedly play a minor role compared to that of the restoration material itself in bacterial colonization.}, } @article {pmid28750737, year = {2017}, author = {Howlin, RP and Cathie, K and Hall-Stoodley, L and Cornelius, V and Duignan, C and Allan, RN and Fernandez, BO and Barraud, N and Bruce, KD and Jefferies, J and Kelso, M and Kjelleberg, S and Rice, SA and Rogers, GB and Pink, S and Smith, C and Sukhtankar, PS and Salib, R and Legg, J and Carroll, M and Daniels, T and Feelisch, M and Stoodley, P and Clarke, SC and Connett, G and Faust, SN and Webb, JS}, title = {Low-Dose Nitric Oxide as Targeted Anti-biofilm Adjunctive Therapy to Treat Chronic Pseudomonas aeruginosa Infection in Cystic Fibrosis.}, journal = {Molecular therapy : the journal of the American Society of Gene Therapy}, volume = {25}, number = {9}, pages = {2104-2116}, pmid = {28750737}, issn = {1525-0024}, support = {//Wellcome Trust/United Kingdom ; //Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adolescent ; Adult ; Anti-Bacterial Agents/*administration & dosage ; Bacterial Load ; Biofilms/*drug effects ; Cystic Fibrosis/*complications ; Dose-Response Relationship, Drug ; Humans ; Middle Aged ; Nitric Oxide/*administration & dosage/metabolism ; Pseudomonas Infections/blood/*drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects ; Randomized Controlled Trials as Topic ; Sputum/microbiology ; Time Factors ; Young Adult ; }, abstract = {Despite aggressive antibiotic therapy, bronchopulmonary colonization by Pseudomonas aeruginosa causes persistent morbidity and mortality in cystic fibrosis (CF). Chronic P. aeruginosa infection in the CF lung is associated with structured, antibiotic-tolerant bacterial aggregates known as biofilms. We have demonstrated the effects of non-bactericidal, low-dose nitric oxide (NO), a signaling molecule that induces biofilm dispersal, as a novel adjunctive therapy for P. aeruginosa biofilm infection in CF in an ex vivo model and a proof-of-concept double-blind clinical trial. Submicromolar NO concentrations alone caused disruption of biofilms within ex vivo CF sputum and a statistically significant decrease in ex vivo biofilm tolerance to tobramycin and tobramycin combined with ceftazidime. In the 12-patient randomized clinical trial, 10 ppm NO inhalation caused significant reduction in P. aeruginosa biofilm aggregates compared with placebo across 7 days of treatment. Our results suggest a benefit of using low-dose NO as adjunctive therapy to enhance the efficacy of antibiotics used to treat acute P. aeruginosa exacerbations in CF. Strategies to induce the disruption of biofilms have the potential to overcome biofilm-associated antibiotic tolerance in CF and other biofilm-related diseases.}, } @article {pmid28748044, year = {2017}, author = {Tawakoli, PN and Neu, TR and Busck, MM and Kuhlicke, U and Schramm, A and Attin, T and Wiedemeier, DB and Schlafer, S}, title = {Visualizing the dental biofilm matrix by means of fluorescence lectin-binding analysis.}, journal = {Journal of oral microbiology}, volume = {9}, number = {1}, pages = {1345581}, pmid = {28748044}, issn = {2000-2297}, abstract = {The extracellular matrix is a poorly studied, yet important component of dental biofilms. Fluorescence lectin-binding analysis (FLBA) is a powerful tool to characterize glycoconjugates in the biofilm matrix. This study aimed to systematically investigate the ability of 75 fluorescently labeled lectins to visualize and quantify extracellular glycoconjugates in dental biofilms. Lectin binding was screened on pooled supragingival biofilm samples collected from 76 subjects using confocal microscopy. FLBA was then performed with 10 selected lectins on biofilms grown in situ for 48 h in the absence of sucrose. For five lectins that proved particularly suitable, stained biovolumes were quantified and correlated to the bacterial composition of the biofilms. Additionally, combinations of up to three differently labeled lectins were tested. Of the 10 lectins, five bound particularly well in 48-h-biofilms: Aleuria aurantia (AAL), Calystega sepiem (Calsepa), Lycopersicon esculentum (LEA), Morniga-G (MNA-G) and Helix pomatia (HPA). No significant correlation between the binding of specific lectins and bacterial composition was found. Fluorescently labeled lectins enable the visualization of glycoconjugates in the dental biofilm matrix. The characterization and quantification of glycoconjugates in dental biofilms require a combination of several lectins. For 48-h-biofilms grown in absence of sucrose, AAL, Calsepa, HPA, LEA, and MNA-G are recommendable.}, } @article {pmid28748041, year = {2017}, author = {Ong, HS and Oettinger-Barak, O and Dashper, SG and Darby, IB and Tan, KH and Reynolds, EC}, title = {Effect of azithromycin on a red complex polymicrobial biofilm.}, journal = {Journal of oral microbiology}, volume = {9}, number = {1}, pages = {1339579}, pmid = {28748041}, issn = {2000-2297}, abstract = {Azithromycin has recently gained popularity for the treatment of periodontal disease, despite sparse literature supporting efficiency in treating periodontal bacterial biofilms. The aim of this study was to evaluate the effect of azithromycin on biofilms comprised of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in comparison to an amoxicillin and metronidazole combination. P. gingivalis W50, T. denticola ATCC35405, and T. forsythia ATCC43037 grown under anaerobic conditions at 37°C were aliquoted into 96-well flat-bottom plates in different combinations with addition of azithromycin or amoxicillin + metronidazole at various concentrations. For the biofilm assay, the plates were incubated at 37°C anaerobically for 48 h, after which the biofilms were stained with crystal violet and measured for absorbance at AU620. In this model, polymicrobial biofilms of P. gingivalis + T. denticola, P. gingivalis + T. forsythia, and T. denticola + T. forsythia were cultured. Combination of all three bacteria enhanced biofilm biomass. Azithromycin demonstrated a minimal biofilm inhibitory concentration (MBIC) of 10.6 mg/L, while the amoxicillin + metronidazole combination was more effective in inhibiting biofilm formation with a MBIC of 1.63 mg/L. Polymicrobial biofilm formation was demonstrated by combination of all three red complex bacteria. Azithromycin was ineffective in preventing biofilm formation within a clinically achievable concentration, whereas the combination of amoxicillin and metronidazole was more effective for this purpose.}, } @article {pmid28748035, year = {2017}, author = {Velsko, IM and Cruz-Almeida, Y and Huang, H and Wallet, SM and Shaddox, LM}, title = {Cytokine response patterns to complex biofilms by mononuclear cells discriminate patient disease status and biofilm dysbiosis.}, journal = {Journal of oral microbiology}, volume = {9}, number = {1}, pages = {1330645}, pmid = {28748035}, issn = {2000-2297}, support = {T90 DE021990/DE/NIDCR NIH HHS/United States ; K01 AG048259/AG/NIA NIH HHS/United States ; R01 DE027301/DE/NIDCR NIH HHS/United States ; P30 AG028740/AG/NIA NIH HHS/United States ; R01 DE019456/DE/NIDCR NIH HHS/United States ; R01 DE019783/DE/NIDCR NIH HHS/United States ; }, abstract = {Localized aggressive periodontitis (LAP) is a rare form of periodontal disease with site-specific rapid tissue destruction. A lipopolysaccharide (LPS) hyper-inflammatory response was shown in LAP using peripheral whole blood, although responses to other bacterial surface components or complex oral biofilms have not been evaluated. Peripheral blood mononuclear cells (PBMCs) from 14 LAP patients, 15 healthy siblings (HS), and 13 unrelated healthy controls (HC) were stimulated with: LPS, lipoteichoic acid, or peptidoglycan; intact or sonically dispersed in vitro-grown biofilms from a LAP disease site, a LAP healthy site, or a healthy control site. Cell culture supernatants were assayed for 14 cyto/chemokines. Discriminant function analysis determined cyto/chemokines that discriminate disease status by response patterns to different stimuli. Qualitative differences in the cytokine response pattern among patient groups were observed to intact and dispersed biofilms, yet responses to healthy and diseased biofilms could not be discriminated. Despite an equivalent magnitude of response, LAP-derived PBMCs demonstrated a qualitatively different pattern of response to LPS and dispersed biofilms. PMBCs from each group responded distinctly to stimulation withsubgingival biofilms. Multiple underlying mechanisms related to bacterial-induced inflammatory responses can culminate in LAP disease initiation and/or progression, and biofilm homeostasis could play an important role.}, } @article {pmid28748032, year = {2017}, author = {Nassar, HM and Gregory, RL}, title = {Biofilm sensitivity of seven Streptococcus mutans strains to different fluoride levels.}, journal = {Journal of oral microbiology}, volume = {9}, number = {1}, pages = {1328265}, pmid = {28748032}, issn = {2000-2297}, abstract = {The effect of fluoride concentrations in dental products could be different depending on the Streptococcus mutans strain. The aim of this study was to investigate the effect of different fluoride concentrations corresponding to dental products on biofilm formation and metabolic activity of S. mutans strains. Seven S. mutans strains (UA159, A32-2, NG8, 10449, UA130, LM7, and OMZ175) were inoculated into 96-well microtiter plates and were tested with various concentrations of sodium fluoride (0.0, 1.0, 1.56, 3.13, 6.25, 12.5, 25, 50, 100, 125, 175, 225, 275, 625, 1,250, 2,250, and 5,500 ppm) for inhibition of biofilm formation and bacterial metabolic activity by recording absorbance values followed by scanning electron microscope (SEM) images. Data were analyzed by one-way analysis of variance and Tukey's tests (α = 5%). Significantly more (p≤0.05) biofilm mass in the presence of fluoride was produced by A32-2 and NG8. UA130, LM7, and OMZ175 were more sensitive to increased fluoride and demonstrated few bacterial cells and extracellular polysaccharide (EPS) production at 100 ppm in SEM images. All strains were unable to produce significant biofilm at concentrations >225 ppm. Patients with tolerantS. mutans strains would potentially benefit less from the inherent antibacterial effect of fluoride.}, } @article {pmid28747596, year = {2017}, author = {Kameda, T and Oka, SY and Morozumi, Y and Terada, K and Toyama, A and Ohkuma, K and Kudo, M and Ikeda, F}, title = {Intraoral electric potential via oral bacterial power generation -A novel mechanism of biofilm formation.}, journal = {Dental materials journal}, volume = {36}, number = {6}, pages = {822-833}, doi = {10.4012/dmj.2016-318}, pmid = {28747596}, issn = {1881-1361}, mesh = {Biofilms/*growth & development ; Dental Enamel/*physiology ; Dental Pellicle/*physiology ; Double-Blind Method ; *Electromagnetic Phenomena ; Humans ; Male ; Oral Hygiene ; Risk Factors ; Smartphone/*statistics & numerical data ; Streptococcus mutans/*growth & development ; Surveys and Questionnaires ; Young Adult ; }, abstract = {In the early stages of biofilm accumulation, the electric charge of the dental enamel and pellicle surfaces is known to be involved. We therefore investigated the relationship between oral hygiene and intraoral electric potential (IoP) in 45 male participants using a double-blind study. IoP, but not body surface electric potential, was loosely correlated with oral hygiene condition (Oral Hygiene Index; OHI). IoP was also loosely correlated with smartphone use; however, there was no significant correlation between smartphone use and OHI. IoP elevation might be caused by OHI elevation resulting from biofilm formation as an internal factor, with smartphone use as an external factor. This in vitro study revealed the generating capacity of Streptococcus mutans accompanied by biofilm accumulation using a microbial fuel cell. These results suggest that IoP elevation is caused by biofilm accumulation induced by power generation of oral bacteria, resulting in elevation of OHI.}, } @article {pmid28747525, year = {2017}, author = {Seifert, HS}, title = {Haemophilus spills its guts to make a biofilm.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {32}, pages = {8444-8446}, pmid = {28747525}, issn = {1091-6490}, support = {R37 AI033493/AI/NIAID NIH HHS/United States ; }, mesh = {*Biofilms ; *Haemophilus ; Haemophilus Infections ; Haemophilus influenzae ; Humans ; }, } @article {pmid28746888, year = {2017}, author = {Jahanizadeh, S and Yazdian, F and Marjani, A and Omidi, M and Rashedi, H}, title = {Curcumin-loaded chitosan/carboxymethyl starch/montmorillonite bio-nanocomposite for reduction of dental bacterial biofilm formation.}, journal = {International journal of biological macromolecules}, volume = {105}, number = {Pt 1}, pages = {757-763}, doi = {10.1016/j.ijbiomac.2017.07.101}, pmid = {28746888}, issn = {1879-0003}, mesh = {Bentonite/*chemistry ; Biofilms/*drug effects/growth & development ; Chitosan/*chemistry ; Curcumin/*chemistry/pharmacology ; Drug Carriers/chemistry ; Drug Liberation ; Hydrogen-Ion Concentration ; Nanocomposites/*chemistry ; Particle Size ; Starch/*analogs & derivatives/chemistry ; Streptococcus mutans/drug effects/physiology ; Tooth/*microbiology ; }, abstract = {A novel bio nanocomposite of Carboxymethyl Starch (CMS)-Chitosan (CS)-Montmorillonite (MMT) was developed for Curcumin delivery. To improve Curcumin entrapment into Cs-CMS-MMT, different ratios of Chitosan (Cs), Carboxymethyl Starch (CMS) and MMT were used. Particle size and Curcumin entrapment efficiency (EE) were highly affected by different formulation variables. Polysaccharide concentration, Cs-CMS ratio and sonication time had significant effect on particle size. MMT addition enhanced the entrapment efficiency. To optimize entrapment efficiency of Curcumin, statistical analysis was used, and an experiment based on screening design performed with two variants. Morphology and structural characterization of nanocomposite and Curcumin entrapment efficiency were analyzed. The optimal formulation had the average particles size of 35.9nm with Curcumin entrapment efficiency of 91%. Finally, the antibacterial activity of bio nanocomposite against Streptococcus mutans was assessed. Curcumin-loaded bio nanocomposite hindered the formation of biofilm on dental models very effectively.}, } @article {pmid28745297, year = {2017}, author = {Mala, R and Annie Aglin, A and Ruby Celsia, AS and Geerthika, S and Kiruthika, N and VazagaPriya, C and Srinivasa Kumar, K}, title = {Foley catheters functionalised with a synergistic combination of antibiotics and silver nanoparticles resist biofilm formation.}, journal = {IET nanobiotechnology}, volume = {11}, number = {5}, pages = {612-620}, pmid = {28745297}, issn = {1751-8741}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; *Biofilms ; Humans ; Kidney Function Tests ; Liver Function Tests ; Metal Nanoparticles/*administration & dosage/chemistry ; Mice ; Silver/*chemistry ; Urinary Catheterization/*instrumentation ; }, abstract = {Foley catheters are inevitable in health care unit. Pathogens colonise and form biofilm on catheter causing catheter-associated urinary tract infection. Therefore, the authors aimed to functionalise catheter to resist biofilm formation. The authors impregnated urinary catheters with a synergistic combination of antibiotics and silver nanoparticles (SNPs) to evaluate antibiofilm efficacy in vitro and in vivo. SNPs were synthesised using Spirulina platensis. Synergy between the SNPs and antibiotics was determined by the checker-board method. In vivo efficacy of the functionalised catheters was assessed in mice. Liver and kidney function tests of mice were performed. The in vitro anti-adherence activity of the functionalised catheters was evaluated after 2 years. Nanoparticle sizes were 42-75 nm. Synergistic activity was observed among SNPs (2 µg/ml), amikacin (6.25 µg/ml), and nitrofurantoin (31.25 µg/ml). In mice, catheters functionalised with combinations of antibiotics and SNPs exhibited no colonisation until Day 14. Blood, liver, and kidney tests were normal. After 2 years, catheters functionalised with antibiotics exhibited 25% inhibition of bacterial adhesion, and catheters functionalised with the nanoparticle-antibiotic combination exhibited 90% inhibition. Impregnation of urinary catheters with a synergistic combination of antibiotics and SNPs is an efficient and promising method for preventing biofilm formation.}, } @article {pmid28745020, year = {2017}, author = {Srivastava, A and Sircaik, S and Husain, F and Thomas, E and Ror, S and Rastogi, S and Alim, D and Bapat, P and Andes, DR and Nobile, CJ and Panwar, SL}, title = {Distinct roles of the 7-transmembrane receptor protein Rta3 in regulating the asymmetric distribution of phosphatidylcholine across the plasma membrane and biofilm formation in Candida albicans.}, journal = {Cellular microbiology}, volume = {19}, number = {12}, pages = {}, pmid = {28745020}, issn = {1462-5822}, support = {R00 AI100896/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Antifungal Agents/metabolism ; Biofilms/*growth & development ; Candida albicans/drug effects/genetics/metabolism/*physiology ; Catheters/microbiology ; Cell Membrane/drug effects/*metabolism ; Fungal Proteins/genetics/*metabolism ; Gene Deletion ; Membrane Proteins/genetics/*metabolism ; Phosphatidylcholines/*metabolism ; Phosphorylcholine/analogs & derivatives/metabolism ; Rats ; }, abstract = {Fungal pathogens such as Candida albicans exhibit several survival mechanisms to evade attack by antifungals and colonise host tissues. Rta3, a member of the Rta1-like family of lipid-translocating exporters has a 7-transmembrane domain topology, similar to the G-protein-coupled receptors and is unique to the fungal kingdom. Our findings point towards a role for the plasma membrane localised Rta3 in providing tolerance to miltefosine, an analogue of alkylphosphocholine, by maintaining mitochondrial energetics. Concurrent with miltefosine susceptibility, the rta3Δ/Δ strain displays increased inward translocation (flip) of fluorophore-labelled phosphatidylcholine (PC) across the plasma membrane attributed to enhanced PC-specific flippase activity. We also assign a novel role to Rta3 in the Bcr1-regulated pathway for in vivo biofilm development. Transcriptome analysis reveals that Rta3 regulates expression of Bcr1 target genes involved in cell surface properties, adhesion, and hyphal growth. We show that rta3Δ/Δ mutant is biofilm-defective in a rat venous catheter model of infection and that BCR1 overexpression rescues this defect, indicating that Bcr1 functions downstream of Rta3 to mediate biofilm formation in C. albicans. The identification of this novel Rta3-dependent regulatory network that governs biofilm formation and PC asymmetry across the plasma membrane will provide important insights into C. albicans pathogenesis.}, } @article {pmid28744570, year = {2017}, author = {Oloketuyi, SF and Khan, F}, title = {Strategies for Biofilm Inhibition and Virulence Attenuation of Foodborne Pathogen-Escherichia coli O157:H7.}, journal = {Current microbiology}, volume = {74}, number = {12}, pages = {1477-1489}, pmid = {28744570}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Escherichia coli O157/drug effects/*pathogenicity/*physiology ; Virulence ; }, abstract = {Enterohemorrhagic Escherichia coli (E. coli) O157:H7, a gram-negative bacteria identified as a foodborne pathogen causing severe disease is of great concern worldwide. The pathogenicity of E. coli O157:H7 is due to the presence of some virulence factors and its ability to form biofilm which resist antimicrobial compounds, withstand harsh environmental condition and protects from the host immune responses. Formation of biofilm is a multistep process such as adhesion, cellular aggregation and productions of extracellular matrix in which colonies are embedded. There are high numbers of research in the discovery of natural and synthetic compounds which can attenuate the E. coli O157:H7 biofilm formation as well as suppress virulence-related genes. The present review article focuses on the steps involved in E. coli O157:H7 biofilm formation, factors associated with virulence and attenuation.}, } @article {pmid28744277, year = {2017}, author = {Gkana, EN and Doulgeraki, AI and Chorianopoulos, NG and Nychas, GE}, title = {Anti-adhesion and Anti-biofilm Potential of Organosilane Nanoparticles against Foodborne Pathogens.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1295}, pmid = {28744277}, issn = {1664-302X}, abstract = {Nowadays, modification of surfaces by nanoparticulate coatings is a simple process that may have applications in reducing the prevalence of bacterial cells both on medical devices and food processing surfaces. To this direction, biofilm biological cycle of Salmonella Typhimurium, Listeria monocytogenes, Escherichia coli O157:H7, Staphylococcus aureus, and Yersinia enterocolitica on stainless steel and glass surfaces, with or without nanocoating was monitored. To achieve this, four different commercial nanoparticle compounds (two for each surface) based on organo-functionalized silanes were selected. In total 10 strains of above species (two for each species) were selected to form biofilms on modified or not, stainless steel or glass surfaces, incubated at 37°C for 72 h. Biofilm population was enumerated by bead vortexing-plate counting method at four time intervals (3, 24, 48, and 72 h). Organosilane based products seemed to affect bacterial attachment on the inert surfaces and/or subsequent biofilm formation, but it was highly dependent on the species and material of surfaces involved. Specifically, reduced bacterial adhesion (at 3 h) of Salmonella and E. coli was observed (P < 0.05) in nanocoating glass surfaces in comparison with the control ones. Moreover, fewer Salmonella and Yersinia biofilm cells were enumerated on stainless steel coupons coated with organosilanes, than on non-coated surfaces at 24 h (P < 0.05). This study gives an insight to the efficacy of organosilanes based coatings against biofilm formation of foodborne pathogens, however, further studies are needed to better understand the impact of surface modification and the underlying mechanisms which are involved in this phenomenon.}, } @article {pmid28744275, year = {2017}, author = {Balamurugan, P and Praveen Krishna, V and Bharath, D and Lavanya, R and Vairaprakash, P and Adline Princy, S}, title = {Staphylococcus aureus Quorum Regulator SarA Targeted Compound, 2-[(Methylamino)methyl]phenol Inhibits Biofilm and Down-Regulates Virulence Genes.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1290}, pmid = {28744275}, issn = {1664-302X}, abstract = {Staphylococcus aureus is a widely acknowledged Gram-positive pathogen for forming biofilm and virulence gene expressions by quorum sensing (QS), a cell to cell communication process. The quorum regulator SarA of S. aureus up-regulates the expression of many virulence factors including biofilm formation to mediate pathogenesis and evasion of the host immune system in the late phases of growth. Thus, inhibiting the production or blocking SarA protein might influence the down-regulation of biofilm and virulence factors. In this context, here we have synthesized 2-[(Methylamino)methyl]phenol, which was specifically targeted toward the quorum regulator SarA through in silico approach in our previous study. The molecule has been evaluated in vitro to validate its antibiofilm activity against clinical S. aureus strains. In addition, antivirulence properties of the inhibitor were confirmed with the observation of a significant reduction in the expression of representative virulence genes like fnbA, hla and hld that are governed under S. aureus QS. Interestingly, the SarA targeted inhibitor showed negligible antimicrobial activity and markedly reduced the minimum inhibitory concentration of conventional antibiotics when used in combination making it a more attractive lead for further clinical tests.}, } @article {pmid28744261, year = {2017}, author = {Gandra, RM and Mc Carron, P and Fernandes, MF and Ramos, LS and Mello, TP and Aor, AC and Branquinha, MH and McCann, M and Devereux, M and Santos, ALS}, title = {Antifungal Potential of Copper(II), Manganese(II) and Silver(I) 1,10-Phenanthroline Chelates Against Multidrug-Resistant Fungal Species Forming the Candida haemulonii Complex: Impact on the Planktonic and Biofilm Lifestyles.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1257}, pmid = {28744261}, issn = {1664-302X}, abstract = {Candida haemulonii, Candida haemulonii var. vulnera and Candida duobushaemulonii, which form the C. haemulonii complex, are emerging etiologic agents of fungal infections known to be resistant to the most commonly used antifungals. The well-established anti-Candida potential of metal complexes containing 1,10-phenanthroline (phen) ligands encouraged us to evaluate different copper(II), manganese(II), and silver(I) phen chelates for their ability to inhibit planktonic growth and biofilm of C. haemulonii species complex. Two novel coordination complexes, {[Cu(3,6,9-tdda)(phen)2].3H2O.EtOH} n and [Ag2(3,6,9-tdda)(phen)4].EtOH (3,6,9-tddaH2 = 3,6,9-trioxaundecanedioic acid), were synthesized in a similar fashion to the other, previously documented, sixteen copper(II), manganese(II), and silver(I) chelates employed herein. Three isolates of each C. haemulonii species complex were used and the effect of the metal chelates on viability was determined utilizing the CLSI standard protocol and on biofilm-growing cells using the XTT assay. Cytotoxicity of the chelates was evaluated by the MTT assay, employing lung epithelial cells. The majority of the metal chelates were capable of interfering with the viability of planktonic-growing cells of all the fungal isolates. The silver complexes were the most effective drugs (overall geometric mean of the minimum inhibitory concentration (GM-MIC) ranged from 0.26 to 2.16 μM), followed by the manganese (overall GM-MIC ranged from 0.87 to 10.71 μM) and copper (overall GM-MIC ranged from 3.37 to >72 μM) chelates. The manganese chelates (CC50 values ranged from 234.51 to >512 μM) were the least toxic to the mammalian cells, followed by the silver (CC50 values ranged from 2.07 to 13.63 μM) and copper (CC50 values ranged from 0.53 to 3.86 μM) compounds. When tested against mature biofilms, the chelates were less active, with MICs ranging from 2- to 33-fold higher levels when compared to the planktonic MIC counterparts. Importantly, manganese(II), copper(II), and silver(I) phen chelates are relatively cheap and easy to synthesize and they offer significant antifungal chemotherapeutic potential for the treatment of highly resistant pathogens.}, } @article {pmid28743614, year = {2018}, author = {Tang, J and Zhu, N and Zhu, Y and Zamir, SM and Wu, Y}, title = {Sustainable pollutant removal by periphytic biofilm via microbial composition shifts induced by uneven distribution of CeO2 nanoparticles.}, journal = {Bioresource technology}, volume = {248}, number = {Pt B}, pages = {75-81}, doi = {10.1016/j.biortech.2017.07.064}, pmid = {28743614}, issn = {1873-2976}, mesh = {*Biofilms ; Cyanobacteria ; *Nanoparticles ; Nitrogen ; Phosphorus ; }, abstract = {The responses of periphytic biofilm to CeO2 nanoparticle (CNP) exposure were explored by investigating community shifts and pollutant removal. Results showed that CNPs entered the sensitive microbial cells in the periphytic biofilm, leading to cytomembrane damage and intracellular reactive oxygen species (ROS) generation. The periphytic biofilm communities were, however, able to adapt to the prolonged exposure and maintain their pollutant removal (i.e., phosphorus, nitrogen and copper, organic matter) performance. Observations under synchrotron radiation scanning transmission X-ray microscopy revealed that fewer CNPs were distributed in algal cells compared to bacterial cells, wherein the transformation between Ce(IV) and Ce(III) occurred. High-throughput sequencing further showed that the proportion of algae, such as Leptolyngbya and Nostoc, significantly increased in the periphytic biofilm exposed to CNPs while the proportion of bacteria, such as Bacilli and Gemmatimonadetes, decreased. This change in community composition might be the primary reason for the sustained pollutant removal performance of the periphytic biofilm.}, } @article {pmid28741178, year = {2018}, author = {Mattei, MR and Frunzo, L and D'Acunto, B and Pechaud, Y and Pirozzi, F and Esposito, G}, title = {Continuum and discrete approach in modeling biofilm development and structure: a review.}, journal = {Journal of mathematical biology}, volume = {76}, number = {4}, pages = {945-1003}, pmid = {28741178}, issn = {1432-1416}, support = {FPA n2010-0009//ErasmusMundus Joint Doctorate Programme ETeCoS3/International ; }, mesh = {Biofilms/drug effects/*growth & development ; Biomass ; Computational Biology ; Computer Simulation ; Drug Resistance, Microbial ; Humans ; Mathematical Concepts ; Microbial Interactions ; *Models, Biological ; Nonlinear Dynamics ; Quorum Sensing ; Systems Analysis ; }, abstract = {The scientific community has recognized that almost 99% of the microbial life on earth is represented by biofilms. Considering the impacts of their sessile lifestyle on both natural and human activities, extensive experimental activity has been carried out to understand how biofilms grow and interact with the environment. Many mathematical models have also been developed to simulate and elucidate the main processes characterizing the biofilm growth. Two main mathematical approaches for biomass representation can be distinguished: continuum and discrete. This review is aimed at exploring the main characteristics of each approach. Continuum models can simulate the biofilm processes in a quantitative and deterministic way. However, they require a multidimensional formulation to take into account the biofilm spatial heterogeneity, which makes the models quite complicated, requiring significant computational effort. Discrete models are more recent and can represent the typical multidimensional structural heterogeneity of biofilm reflecting the experimental expectations, but they generate computational results including elements of randomness and introduce stochastic effects into the solutions.}, } @article {pmid28741172, year = {2018}, author = {Krämer, N and Schmidt, M and Lücker, S and Domann, E and Frankenberger, R}, title = {Glass ionomer cement inhibits secondary caries in an in vitro biofilm model.}, journal = {Clinical oral investigations}, volume = {22}, number = {2}, pages = {1019-1031}, pmid = {28741172}, issn = {1436-3771}, mesh = {*Biofilms ; Bisphenol A-Glycidyl Methacrylate ; Composite Resins/chemistry ; Dental Caries/*microbiology/*prevention & control ; Dental Restoration, Permanent/*methods ; Glass Ionomer Cements/chemistry/*pharmacology ; Humans ; In Vitro Techniques ; Microscopy, Fluorescence ; Molar, Third ; Resins, Synthetic ; }, abstract = {OBJECTIVES: The objective of this study was to investigate the effect of different glass ionomer cements on secondary caries inhibition in a fully automated in vitro biofilm model.

MATERIALS AND METHODS: One hundred and twenty-four extracted third molars received class V cavities and were filled with one conventional (Ketac Molar/KM), and two resin-modified glass ionomer cements (Photac Fil/PF, Ketac N100/KN, 3M Espe). A bonded resin composite (Single Bond Plus/Filtek Supreme XTE) served as control. After 14 days water storage at 37 °C, specimens were thermocycled (10,000 × 5/55 °C). Over a period of 10 days, specimens were subjected to cariogenic challenge for 3/4/6 h/day. Demineralization was caused by Streptococcus mutans (DSM 20523) alternatingly being rinsed over specimens using artificial saliva. After biological loading, teeth were cut longitudinally and demineralization depths were evaluated at the margins and at a distance of 0.5 mm from the margins using fluorescence microscopy. Marginal quality was investigated under a SEM at ×200 magnification.

RESULTS: Four-hour demineralization depths were for enamel margins (EM), enamel (E), dentin margin (DM), and dentin (D) (μm ± SD): KM: EM 12 ± 8, E 33 ± 7, DM 56 ± 11, D 79 ± 6; PF: EM 19 ± 13, E 34 ± 13, DM 53 ± 10, D 77 ± 12; and KN: EM 26 ± 5, E 38 ± 6, DM 57 ± 11, D 71 ± 7. For all glass ionomer cements (GICs), demineralization depth at the margins was less compared to 0.5 mm distance, with demineralization depth having been correlated to duration of cariogenic challenge (ANOVA [mod. LSD, p < 0.05]). Compared to the bonded resin composite, all GICs exhibited caries inhibition at restoration margins in enamel and dentin.

CONCLUSIONS: Fluoride-releasing GIC materials exhibit a secondary caries inhibiting effect in vitro.

CLINICAL RELEVANCE: Glass ionomer cements have a higher secondary caries inhibiting effect than resin composites.}, } @article {pmid28738195, year = {2017}, author = {Pérez-Ibarreche, M and Mendoza, LM and Vignolo, G and Fadda, S}, title = {Proteomic and genetics insights on the response of the bacteriocinogenic Lactobacillus sakei CRL1862 during biofilm formation on stainless steel surface at 10°C.}, journal = {International journal of food microbiology}, volume = {258}, number = {}, pages = {18-27}, doi = {10.1016/j.ijfoodmicro.2017.07.003}, pmid = {28738195}, issn = {1879-3460}, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Disinfectants/pharmacology ; Electrophoresis, Gel, Two-Dimensional ; Food-Processing Industry ; Gene Expression Profiling ; Latilactobacillus sakei/genetics/*growth & development/metabolism ; Listeria monocytogenes/growth & development ; Proteome/genetics ; Proteomics ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; *Stainless Steel ; }, abstract = {Some lactic acid bacteria have the ability to form biofilms on food-industry surfaces and this property could be used to control food pathogens colonization. Lactobacillus sakei CR1862 was selected considering its bacteriocinogenic nature and ability to adhere to abiotic surfaces at low temperatures. In this study, the proteome of L. sakei CRL1862 grown either under biofilm on stainless steel surface and planktonic modes of growth at 10°C, was investigated. Using two-dimensional gel electrophoresis, 29 out of 43 statistically significant spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Ten proteins resulted up-regulated whereas 16 were down-regulated during biofilm formation. Differentially expressed proteins were found to belong to carbohydrate, nucleotide, aminoacid and lipid metabolisms as well as translation, peptide hydrolysis, cell envelope/cell wall biosynthesis, adaption to atypical conditions and protein secretion. Some proteins related to carbohydrate and nucleotide metabolisms, translation and peptide degradation were overexpressed whereas those associated to stress conditions were synthesized in lower amounts. It seems that conditions for biofilm development would not imply a stressful environment for L. sakei CRL1862 cells, directing its growth strategy towards glycolytic flux regulation and reinforcing protein synthesis. In addition, L. sakei CRL1862 showed to harbor nine out of ten assayed genes involved in biofilm formation and protein anchoring. By applying qRT-PCR analysis, four of these genes showed to be up regulated, srtA2 being the most remarkable. The results of this study contribute to the knowledge of the physiology of L. sakei CRL1862 growing in biofilm on a characteristic food contact surface. The use of this strain as green biocide preventing L. monocytogenes post-processing contamination on industrial surfaces may be considered.}, } @article {pmid28738143, year = {2017}, author = {Wu, Y and Tang, J and Liu, J and Graham, B and Kerr, PG and Chen, H}, title = {Sustained High Nutrient Supply As an Allelopathic Trigger between Periphytic Biofilm and Microcystis aeruginosa.}, journal = {Environmental science & technology}, volume = {51}, number = {17}, pages = {9614-9623}, doi = {10.1021/acs.est.7b01027}, pmid = {28738143}, issn = {1520-5851}, mesh = {*Allelopathy ; *Biofilms ; Cyanobacteria ; *Microcystis ; }, abstract = {Allelopathy among aquatic organisms, especially microorganisms, has received growing attention in recent years for its role in shaping interactions with bloom-forming algae. Many studies have shown that allelopathy occurs and increases under nutrient limiting conditions. However, to date there is no reported direct evidence to indicate that allelopathy occurs under the condition of constant high nutrient supply. Here we report the allelopathic action of periphytic biofilm on bloom-forming cyanobacteria (Microcystis aeruginosa), which was triggered by the stress of high nutrient conditions, and continues while nutrients are maintained at high levels (trophic state index at 159 and 171). The experimental evidence indicates that the electron transport from photosystem II (PS II) to photosystem I (PS I) in M. aeruginosa is interrupted by the identified allelochemicals, (9Z)-Octadec-9-enoic acid and (9Z)-Hexadec-9-enoic acid, leading to the failure of photosynthesis and the subsequent death of M. aeruginosa. Our findings indicate that the nutrient stress of constant high nutrient supply may be a newly recognized trigger causing allelopathy between microbial competitors, and therefore opening a new direction for the better management of ecological processes in cyanobacteria-dominated and hyper-eutrophic waters.}, } @article {pmid28736916, year = {2017}, author = {Marcuzzo, AV and Tofanelli, M and Boscolo Nata, F and Gatto, A and Tirelli, G}, title = {Hyaluronate effect on bacterial biofilm in ENT district infections: a review.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {9}, pages = {763-772}, doi = {10.1111/apm.12728}, pmid = {28736916}, issn = {1600-0463}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*growth & development ; Drug Resistance, Bacterial ; Ear/microbiology ; Humans ; Hyaluronic Acid/*therapeutic use ; Nose/microbiology ; Pharyngitis/*drug therapy/microbiology ; Pharynx/microbiology ; Sinusitis/*drug therapy/microbiology ; }, abstract = {Bacterial resistance is a growing phenomenon which led the scientific community to search for new therapeutic targets, such as biofilm. A bacterial biofilm is a surface-associated agglomerate of microorganisms embedded in a self-produced extracellular polymeric matrix made of polysaccharides, nucleic acids, and proteins. Scientific literature offers several reports on a biofilm's role in infections regarding various body districts. The presence of a bacterial biofilm is responsible for poor efficacy of antibiotic therapies along with bacterial infections in ear, nose, and throat (ENT) districts such as the oral cavity, ear, nasal cavities, and nasal sinuses. In particular, bacterial biofilms are associated with recalcitrant and symptomatically more severe forms of chronic rhinosinusitis. As of today, there are no therapeutic options for the eradication of bacterial biofilm in ENT districts. Hyaluronic acid is a glycosaminoglycan composed of glucuronic acid and N-acetylglucosamine disaccharide units. Its efficacy in treating rhinosinusitis, whether or not associated with polyposis, is well documented, as well as results from its effects on mucociliary clearance, free radical production and mucosal repair. This review's aim is to evaluate the role of bacterial biofilms and the action exerted on it by hyaluronic acid in ENT pathology, with particular attention to the rhinosinusal district. In conclusion, this paper underlines how the efficacy of hyaluronate as an anti-bacterial biofilm agent is well demonstrated by in vitro studies; it is, however, only preliminarily demonstrated by clinical studies.}, } @article {pmid28736523, year = {2017}, author = {Ding, WY and Li, YH and Lian, H and Ai, XY and Zhao, YL and Yang, YB and Han, Q and Liu, X and Chen, XY and He, Z}, title = {Sub-Minimum Inhibitory Concentrations of Rhubarb Water Extracts Inhibit Streptococcus suis Biofilm Formation.}, journal = {Frontiers in pharmacology}, volume = {8}, number = {}, pages = {425}, pmid = {28736523}, issn = {1663-9812}, abstract = {Streptococcus suis is one of the most important swine pathogens, which can cause persistent infection by forming biofilms. In this study, sub-minimum inhibitory concentration (sub-MIC) of rhubarb water extracts were found to inhibit biofilm formation. Two-component signal transduction systems (TCSs), transcriptional regulators, and DNA binding proteins were compared under two conditions: (1) cells treated with sub-MIC rhubarb water extracts and (2) untreated cells. Using an isobaric tags for relative and absolute quantitation (iTRAQ) strategy, we found that TCSs constituent proteins of histidine kinase and response regulator were significantly down-regulated. This down-regulation can affect the transfer of information during biofilm formation. The transcriptional regulators and DNA binding proteins that can interact with TCSs and interrupt gene transcription were also significantly altered. For these reasons, the levels of protein expressions varied in different parts of the treated vs. untreated cells. In summary, rhubarb water extracts might serve as potential inhibitor for the control of S. suis biofilm formation. The change in TCSs, transcriptional regulators, and DNA binding proteins may be important factors in S. suis biofilm inhibition.}, } @article {pmid28735852, year = {2017}, author = {Dixit, S and Dubey, RC and Maheshwari, DK and Seth, PK and Bajpai, VK}, title = {Roles of quorum sensing molecules from Rhizobium etli RT1 in bacterial motility and biofilm formation.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {48}, number = {4}, pages = {815-821}, pmid = {28735852}, issn = {1678-4405}, mesh = {4-Butyrolactone/*analogs & derivatives/chemistry/metabolism ; *Biofilms ; Lens Plant/microbiology ; Plant Roots/microbiology ; *Quorum Sensing ; Rhizobium etli/chemistry/genetics/isolation & purification/*physiology ; }, abstract = {Strain RT1 was isolated from root nodules of Lens culinaris (a lentil) and characterized as Rhizobium etli (a Gram-negative soil-borne bacterium) by 16S rDNA sequencing and phylogenetic analysis. The signaling molecules produced by R. etli (RT1) were detected and identified by high-performance liquid chromatography coupled with mass spectrometry. The most abundant and biologically active N-acyl homoserine lactone molecules (3-oxo-C8-HSL and 3-OH-C14-HSL) were detected in the ethyl acetate extract of RT1. The biological role of 3-oxo-C8-HSL was evaluated in RT1. Bacterial motility and biofilm formation were affected or modified on increasing concentrations of 3-oxo-C8-HSL. Results confirmed the existence of cell communication in RT1 mediated by 3-oxo-C8-HSL, and positive correlations were found among quorum sensing, motility and biofilm formation in RT1.}, } @article {pmid28734589, year = {2018}, author = {Zhu, Y and Zhang, J and Zhu, N and Tang, J and Liu, J and Sun, P and Wu, Y and Wong, PK}, title = {Phosphorus and Cu[2+] removal by periphytic biofilm stimulated by upconversion phosphors doped with Pr[3+]-Li.}, journal = {Bioresource technology}, volume = {248}, number = {Pt B}, pages = {68-74}, doi = {10.1016/j.biortech.2017.07.027}, pmid = {28734589}, issn = {1873-2976}, mesh = {Bacteria ; *Biofilms ; Biomass ; Ions ; *Phosphorus ; }, abstract = {Upconversion phosphors (UCPs) can convert visible light into luminescence, such as UV, which can regulate the growth of microbes. Based on these fundamentals, the community composition of periphytic biofilms stimulated by UCPs doped with Pr[3+]-Li[+] was proposed to augment the removal of phosphorus (P) and copper (Cu). Results showed that the biofilms with community composition optimized by UCPs doped with Pr[3+]-Li[+] had high P and Cu[2+] removal rates. This was partly due to overall bacterial and algal abundance and biomass increases. The synergistic actions of algal, bacterial biomass and carbon metabolic capacity in the Pr-Li stimulated biofilms facilitated the removal of P and Cu[2+]. The results show that the stimulation of periphytic biofilms by lanthanide-doped UCPs is a promising approach for augmenting P and Cu[2+] removal.}, } @article {pmid28733283, year = {2017}, author = {Falghoush, A and Beyenal, H and Besser, TE and Omsland, A and Call, DR}, title = {Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {19}, pages = {}, pmid = {28733283}, issn = {1098-5336}, mesh = {Acinetobacter baumannii/*drug effects/growth & development/physiology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Microbial Sensitivity Tests ; Osmosis ; Polyethylene Glycols/pharmacology ; Polysaccharides/pharmacology ; Sucrose/pharmacology ; Tobramycin/pharmacology ; }, abstract = {Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log (P < 0.05). Increasing concentrations of osmotic compounds improved the effect, but there was a trade-off with increasing solution viscosity, whereby low-molecular-mass compounds (sucrose, 400-Da PEG) worked better than higher-mass compounds (maltodextrin, 3,350-Da PEG). Ten other A. baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity (r[2] > 0.82; P < 0.002), and the relationship was generalizable for biofilms formed by A. baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics.IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities, but viscosity is a limiting factor, and the most effective compounds have lower molecular mass. The synergism between osmotic compounds and antibiotics is also dependent on the hydrophobicity and mass of the antibiotics. The statistical models presented herein provide a basis for predicting the optimal combination of osmotic compounds and antibiotics against surface biofilms communities.}, } @article {pmid28732564, year = {2018}, author = {Chiang, SR and Jung, F and Tang, HJ and Chen, CH and Chen, CC and Chou, HY and Chuang, YC}, title = {Desiccation and ethanol resistances of multidrug resistant Acinetobacter baumannii embedded in biofilm: The favorable antiseptic efficacy of combination chlorhexidine gluconate and ethanol.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {51}, number = {6}, pages = {770-777}, doi = {10.1016/j.jmii.2017.02.003}, pmid = {28732564}, issn = {1995-9133}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/*physiology ; Adaptation, Physiological ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Chlorhexidine/*analogs & derivatives/pharmacology ; *Desiccation ; Drug Resistance, Multiple, Bacterial/*drug effects ; Drug Synergism ; *Ethanol/metabolism/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {BACKGROUND/PURPOSE: Globally, multidrug-resistant Acinetobacter baumannii (MDRAB) has emerged as an important pathogen in nosocomial outbreaks. This study aimed to investigate the correlation between the biofilm formation and survival of MDRABs, and to investigate the antiseptic efficacy of hand sanitizers for the MDRABs, embedded with biofilm (MDRAB-Bs).

METHODS: The MDRABs were selected randomly after pulsed-field gel electrophoresis (PFGE), and their biofilm formation was analyzed. Desiccation and ethanol tolerances were assayed to test the bacterial survival. The antiseptic efficacy of combined chlorhexidine gluconate (CHG) and 70% ethanol agents against MDRAB-Bs were compared with the 70% ethanol cleanser.

RESULTS: Eleven MDRABs, which varied in biofilm formation (MRDAB-B) and planktonic type (MDRAB-P), were tested. In desiccation survival, the mean survival time for the MDRAB-Bs was 49.0 days which was significantly higher than that of their planktonic type (17.3 days) (P < 0.005). The MDRAB-Ps could be eliminated after a 10 min contact with a 30% ethanol agent, however, it took 10 min of 70% ethanol to eliminate the MDRAB-Bs. On the other hand, a 2% CHG in 70% ethanol solution completely eliminated all MDRAB-Bs after 1 min contacted time. The 2% CHG in 70% ethanol agent provided a significantly superior efficacy than the 70% ethanol solution at eliminating the MDRAB-Bs (P < 0.005).

CONCLUSION: MDRAB with biofilm-formation presented significantly higher desiccation and ethanol resistances than their planktonic type. Moreover, the 2% CHG in 70% ethanol agent provided a superior antiseptic efficacy for MDRAB-Bs than that of the 70% ethanol agent.}, } @article {pmid28732010, year = {2017}, author = {Carrel, M and Beltran, MA and Morales, VL and Derlon, N and Morgenroth, E and Kaufmann, R and Holzner, M}, title = {Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools.}, journal = {PloS one}, volume = {12}, number = {7}, pages = {e0180374}, pmid = {28732010}, issn = {1932-6203}, mesh = {Barium Sulfate ; *Biofilms ; Contrast Media ; Ferrous Compounds ; Fluorocarbon Polymers ; Imaging, Three-Dimensional/methods ; Porosity ; Rheology ; Tomography, X-Ray/*methods ; Water ; }, abstract = {X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample. Here, we use a natural inorganic compound, namely iron sulfate, as a contrast agent progressively bounded in dilute or colloidal form into the EPS matrix during biofilm growth. By combining a very long source-to-detector distance on a X-ray laboratory source with a Lorentzian filter implemented prior to tomographic reconstruction, we substantially increase the contrast between the biofilm and the surrounding liquid, which allows revealing the 3D biofilm morphology. A comparison of this new method with the method proposed by Davit et al (Davit et al., 2011), which uses barium sulfate as a contrast agent to mark the liquid phase was performed. Quantitative evaluations between the methods revealed substantial differences for the volumetric fractions obtained from both methods. Namely, contrast agent-biofilm interactions (e.g. biofilm detachment) occurring during barium sulfate injection caused a reduction of the biofilm volumetric fraction of more than 50% and displacement of biofilm patches elsewhere in the column. Two key advantages of the newly proposed method are that passive addition of iron sulfate maintains the integrity of the biofilm prior to imaging, and that the biofilm itself is marked by the contrast agent, rather than the liquid phase as in other available methods. The iron sulfate method presented can be applied to understand biofilm development and bioclogging mechanisms in porous materials and the obtained biofilm morphology could be an ideal basis for 3D numerical calculations of hydrodynamic conditions to investigate biofilm-flow coupling.}, } @article {pmid28731279, year = {2017}, author = {Velmourougane, K and Prasanna, R}, title = {Influence of l-amino acids on aggregation and biofilm formation in Azotobacter chroococcum and Trichoderma viride.}, journal = {Journal of applied microbiology}, volume = {123}, number = {4}, pages = {977-991}, doi = {10.1111/jam.13534}, pmid = {28731279}, issn = {1365-2672}, mesh = {Amino Acids ; Azotobacter/cytology/*physiology ; Biofilms/*growth & development ; Carbohydrates ; Cellular Microenvironment ; *Microbial Interactions ; Plankton ; Principal Component Analysis ; Trichoderma/cytology/*physiology ; }, abstract = {AIM: The effects of l-amino acids on growth and biofilm formation in Azotobacter chroococcum (Az) and Trichoderma viride (Tv) as single (Az, Tv) and staggered inoculated cultures (Az-Tv, Tv-Az) were investigated.

METHODS AND RESULTS: A preliminary study using a set of 20 l-amino acids, identified 6 amino acids (l-Glu, l-Gln, l-His, l-Ser, l-Thr and l-Trp) which significantly enhanced growth and biofilm formation. Supplementation of these amino acids at different concentrations revealed that 40 mmol l[-1] was most effective. l-Glu and l-Gln favoured planktonic growth in both single and in staggered inoculated cultures, while l-Trp and l-Thr, enhanced aggregation and biofilm formation. Addition of l-Glu or l-Gln increased carbohydrate content and planktonic population. Principal component analysis revealed the significant role of proteins in growth and biofilm formation, particularly with supplementation of l-Trp, l-Thr and l-Ser. Azotobacter was found to function better as biofilm under staggered inoculated culture with Trichoderma.

CONCLUSIONS: The results illustrate that amino acids play crucial roles in microbial biofilm formation, by influencing growth, aggregation and carbohydrates synthesized.

The differential and specific roles of amino acids on biofilm formation are of significance for agriculturally important micro-organisms that grow as biofilms, colonize and benefit the plants more effectively.}, } @article {pmid28731269, year = {2017}, author = {Vuotto, C and Longo, F and Pascolini, C and Donelli, G and Balice, MP and Libori, MF and Tiracchia, V and Salvia, A and Varaldo, PE}, title = {Biofilm formation and antibiotic resistance in Klebsiella pneumoniae urinary strains.}, journal = {Journal of applied microbiology}, volume = {123}, number = {4}, pages = {1003-1018}, doi = {10.1111/jam.13533}, pmid = {28731269}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Carbapenems/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Klebsiella pneumoniae/*drug effects/genetics/physiology ; Porins/genetics ; Quorum Sensing/drug effects ; Virulence Factors/metabolism ; }, abstract = {AIMS: Multidrug-resistant Klebsiella pneumoniae has become a relevant healthcare-associated pathogen. Capsule, type 1 and 3 fimbriae (mrkA gene), type 2 quorum-sensing system (luxS), synthesis of D-galactan I (wbbM), LPS transport (wzm) and poly-beta-1,6-N-acetyl-D-glucosamine (pgaA) seem involved in K. pneumoniae biofilm. Nonenzymatic antibiotic resistance is related to nonexpression or mutation of porins (OmpK35 and OmpK36), and efflux pump (acrB) overexpression. The aim of this study was to analyse some virulence factors of K. pneumoniae isolates, and to evaluate possible correlations between their antibiotic resistance profile and ability to form biofilm.

METHODS AND RESULTS: Quantitative biofilm production assay, congo red agar test and string test were performed on 120 isolates clustered in 56 extensively drug-resistant (XDR), 40 MDR and 24 susceptible (S) strains. Nine representative strains were analysed by real-time RT-PCR for the expression of antibiotic resistance (OmpK35, OmpK36, acrB) and biofilm production genes (mrkA, luxS, pga, wbbM, wzm) during planktonic and sessile growth. XDR isolates showed a higher ability to form biofilm (91·07%) and to produce polysaccharides (78·57%) when compared to MDR and S strains. In biofilm-growing XDR strains, seven of eight genes were upregulated, with the only exception of OmpK36.

CONCLUSIONS: XDR strains exhibited phenotypic and genotypic features supporting a significant growth as biofilm.

This study produces new findings that highlight a positive correlation between antibiotic resistance profile and biofilm-forming ability in XDR K. pneumoniae strains. These new evidences might contribute to the progress in selection of therapeutic treatments of infections caused by K. pneumoniae resistant also to the 'last line of defence' antibiotics, that is, carbapenems.}, } @article {pmid28728145, year = {2017}, author = {Schlafer, S and Meyer, RL and Dige, I and Regina, VR}, title = {Extracellular DNA Contributes to Dental Biofilm Stability.}, journal = {Caries research}, volume = {51}, number = {4}, pages = {436-442}, doi = {10.1159/000477447}, pmid = {28728145}, issn = {1421-976X}, mesh = {Adult ; *Biofilms ; DNA, Bacterial/analysis/*physiology ; Female ; Humans ; Male ; Young Adult ; }, abstract = {Extracellular DNA (eDNA) is a major matrix component of many bacterial biofilms. While the presence of eDNA and its role in biofilm stability have been demonstrated for several laboratory biofilms of oral bacteria, there is no data available on the presence and function of eDNA in in vivo grown dental biofilms. This study aimed to determine whether eDNA was part of the matrix in biofilms grown in situ in the absence of sucrose and whether treatment with DNase dispersed biofilms grown for 2.5, 5, 7.5, 16.5, or 24 h. Three hundred biofilms from 10 study participants were collected and treated with either DNase or heat-inactivated DNase for 1 h. The bacterial biovolume was determined with digital image analysis. Staining with TOTO®-1 allowed visualization of eDNA both on bacterial cell surfaces and, with a cloud-like appearance, in the intercellular space. DNase treatment strongly reduced the amount of biofilm in very early stages of growth (up to 7.5 h), but the treatment effect decreased with increasing biofilm age. This study proves the involvement of eDNA in dental biofilm formation and its importance for biofilm stability in the earliest stages. Further research is required to uncover the interplay of eDNA and other matrix components and to explore the therapeutic potential of DNase treatment for biofilm control.}, } @article {pmid28725336, year = {2017}, author = {Paul, S and Ludeña, Y and Villena, GK and Yu, F and Sherman, DH and Gutiérrez-Correa, M}, title = {High-quality draft genome sequence of a biofilm forming lignocellulolytic Aspergillus niger strain ATCC 10864.}, journal = {Standards in genomic sciences}, volume = {12}, number = {}, pages = {37}, pmid = {28725336}, issn = {1944-3277}, abstract = {Filamentous fungus Aspergillus niger has high industrial value due to their lignocellulolytic enzyme activities and ATCC 10864 is one of the few type strains of A. niger which has a unique biofilm forming capability. Here we report the first draft genome sequence of A. niger ATCC 10864 strain. The genome of A. niger ATCC 10864 is 36,172,237 bp long and comprise of 310 scaffolds with 49.5% average GC content. A total of 10,804 protein-coding genes were predicted among which 10,761 genes were with putative functions. A. niger ATCC 10864 genome coded for 709 putative carbohydrate active enzyme families distributed in six functional categories and among them glycoside hydrolases (GHs) represent the most number of families (279). Genes that include pepA, brlA, exgA, LaeA, rodA, GCN have also been identified in this study, which may play a role in biofilm formation. This high-quality draft genome sequence will facilitate our understanding of the mechanisms behind fungal biofilm formation and higher lignocellulolytic enzyme production.}, } @article {pmid28724953, year = {2017}, author = {Vaidya, MY and McBain, AJ and Butler, JA and Banks, CE and Whitehead, KA}, title = {Antimicrobial Efficacy and Synergy of Metal Ions against Enterococcus faecium, Klebsiella pneumoniae and Acinetobacter baumannii in Planktonic and Biofilm Phenotypes.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5911}, pmid = {28724953}, issn = {2045-2322}, mesh = {Acinetobacter baumannii/*drug effects ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Enterococcus faecium/*drug effects ; Ions ; Klebsiella pneumoniae/*drug effects ; Metals/*pharmacology ; Microbial Sensitivity Tests ; Phenotype ; Plankton/*drug effects ; }, abstract = {The effects of metal ion solutions (silver, copper, platinum, gold and palladium) were determined individually and in combination against Enterococcus faecium, Acinetobacter baumannii and Klebsiella pneumoniae. Platinum, gold and palladium showed the greatest antimicrobial efficacy in zone of inhibition (ZoI) assays. When tested in combinations using ZoI assays, gold/platinum, gold/palladium and platinum/palladium were indicative of synergy. Microbial inhibitory concentration demonstrated platinum and gold against Enterococcus faecium, platinum against Klebsiella pneumoniae and platinum and silver against Acinetobacter baumannii were optimal. Minimal bactericidal concentrations determined the greatest bactericidal activity was again platinum gold and palladium against all three bacteria. Fractional Inhibitory Concentration (FIC) studies demonstrated that the silver/platinum combination against Enterococcus faecium, and silver/copper combination against Acinetobacter baumannii demonstrated antimicrobial synergy. Following crystal violet biofilm assays for single metal ion solutions, antimicrobial efficacies were demonstrated for all the metals against all the bacteria Synergistic assays against biofilms demonstrated gold/palladium, gold/platinumand platinum/palladium resulted in the greatest antimicrobial efficacy. Overall, platinum, palladium and gold metal ion solutions in individual use or combination demonstrated the greatest antimicrobial efficacies against planktonic or biofilm bacteria. This work demonstrates the potential for using a range of metal ions, as biocidal formulations against both planktonic or biofilm bacteria.}, } @article {pmid28724921, year = {2017}, author = {Eriksson, L and Lif Holgerson, P and Johansson, I}, title = {Saliva and tooth biofilm bacterial microbiota in adolescents in a low caries community.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5861}, pmid = {28724921}, issn = {2045-2322}, mesh = {Adolescent ; *Biofilms ; Dental Caries/*microbiology ; Female ; Humans ; Least-Squares Analysis ; Male ; Phylogeny ; Reproducibility of Results ; Saliva/*microbiology ; Sequence Analysis, DNA ; Species Specificity ; Tooth/*microbiology ; Young Adult ; }, abstract = {The oral cavity harbours a complex microbiome that is linked to dental diseases and serves as a route to other parts of the body. Here, the aims were to characterize the oral microbiota by deep sequencing in a low-caries population with regular dental care since childhood and search for association with caries prevalence and incidence. Saliva and tooth biofilm from 17-year-olds and mock bacteria communities were analysed using 16S rDNA Illumina MiSeq (v3-v4) and PacBio SMRT (v1-v8) sequencing including validity and reliability estimates. Caries was scored at 17 and 19 years of age. Both sequencing platforms revealed that Firmicutes dominated in the saliva, whereas Firmicutes and Actinobacteria abundances were similar in tooth biofilm. Saliva microbiota discriminated caries-affected from caries-free adolescents, with enumeration of Scardovia wiggsiae, Streptococcus mutans, Bifidobacterium longum, Leptotrichia sp. HOT498, and Selenomonas spp. in caries-affected participants. Adolescents with B. longum in saliva had significantly higher 2-year caries increment. PacBio SMRT revealed Corynebacterium matruchotii as the most prevalent species in tooth biofilm. In conclusion, both sequencing methods were reliable and valid for oral samples, and saliva microbiota was associated with cross-sectional caries prevalence, especially S. wiggsiae, S. mutans, and B. longum; the latter also with the 2-year caries incidence.}, } @article {pmid28723923, year = {2017}, author = {Marioni, J and Bresolí-Obach, R and Agut, M and Comini, LR and Cabrera, JL and Paraje, MG and Nonell, S and Núñez Montoya, SC}, title = {On the mechanism of Candida tropicalis biofilm reduction by the combined action of naturally-occurring anthraquinones and blue light.}, journal = {PloS one}, volume = {12}, number = {7}, pages = {e0181517}, pmid = {28723923}, issn = {1932-6203}, mesh = {Anthraquinones/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida tropicalis/*drug effects/metabolism ; *Light ; Reactive Oxygen Species ; Superoxides/metabolism ; }, abstract = {The photoprocesses involved in the photo-induced Candida tropicalis biofilm reduction by two natural anthraquinones (AQs), rubiadin (1) and rubiadin-1-methyl ether (2), were examined. Production of singlet oxygen (1O2) and of superoxide radical anion (O2•-) was studied. Although it was not possible to detect the triplet state absorption of any AQs in biofilms, observation of 1O2 phosphorescence incubated with deuterated Phosphate Buffer Solution, indicated that this species is actually formed in biofilms. 2 was accumulated in the biofilm to a greater extent than 1 and produced measurable amounts of O2•- after 3h incubation in biofilms. The effect of reactive oxygen species scavengers on the photo-induced biofilm reduction showed that Tiron (a specific O2•- scavenger) is most effective than sodium azide (a specific 1O2 quencher). This suggests that O2•- formed by electron transfer quenching of the AQs excited states, is the main photosensitizing mechanism involved in the photo-induced antibiofilm activity, whereas 1O2 participation seems of lesser importance.}, } @article {pmid28722830, year = {2018}, author = {Mori, Y and Hosoi, Y and Ishikawa, S and Hayashi, K and Asai, Y and Ohnishi, H and Shimatani, M and Inoue, K and Ikeda, K and Nakayashiki, H and Nishimura, Y and Ohnishi, K and Kiba, A and Kai, K and Hikichi, Y}, title = {Ralfuranones contribute to mushroom-type biofilm formation by Ralstonia solanacearum strain OE1-1.}, journal = {Molecular plant pathology}, volume = {19}, number = {4}, pages = {975-985}, pmid = {28722830}, issn = {1364-3703}, mesh = {Biofilms/*growth & development ; Lactones/*metabolism ; Solanum lycopersicum/microbiology ; Quorum Sensing ; Ralstonia solanacearum/*growth & development/*metabolism ; Virulence ; }, abstract = {After invasion into intercellular spaces of tomato plants, the soil-borne, plant-pathogenic Ralstonia solanacearum strain OE1-1 forms mushroom-shaped biofilms (mushroom-type biofilms, mBFs) on tomato cells, leading to its virulence. The strain OE1-1 produces aryl-furanone secondary metabolites, ralfuranones (A, B, J, K and L), dependent on the quorum sensing (QS) system, with methyl 3-hydroxymyristate (3-OH MAME) synthesized by PhcB as a QS signal. Ralfuranones are associated with the feedback loop of the QS system. A ralfuranone productivity-deficient mutant (ΔralA) exhibited significantly reduced growth in intercellular spaces compared with strain OE1-1, losing its virulence. To analyse the function of ralfuranones in mBF formation by OE1-1 cells, we observed cell aggregates of R. solanacearum strains statically incubated in tomato apoplast fluids on filters under a scanning electron microscope. The ΔralA strain formed significantly fewer microcolonies and mBFs than strain OE1-1. Supplementation of ralfuranones A, B, J and K, but not L, significantly enhanced the development of mBF formation by ΔralA. Furthermore, a phcB- and ralA-deleted mutant (ΔphcB/ralA) exhibited less formation of mBFs than OE1-1, although a QS-deficient, phcB-deleted mutant formed mBFs similar to OE1-1. Supplementation with 3-OH MAME significantly reduced the formation of mBFs by ΔphcB/ralA. The application of each ralfuranone significantly increased the formation of mBFs by ΔphcB/ralA supplied with 3-OH MAME. Together, our findings indicate that ralfuranones are implicated not only in the development of mBFs by strain OE1-1, but also in the suppression of QS-mediated negative regulation of mBF formation.}, } @article {pmid28721848, year = {2017}, author = {Saffari, M and Karami, S and Firoozeh, F and Sehat, M}, title = {Evaluation of biofilm-specific antimicrobial resistance genes in Pseudomonas aeruginosa isolates in Farabi Hospital.}, journal = {Journal of medical microbiology}, volume = {66}, number = {7}, pages = {905-909}, doi = {10.1099/jmm.0.000521}, pmid = {28721848}, issn = {1473-5644}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biofilms/*growth & development ; Child ; Child, Preschool ; Disk Diffusion Antimicrobial Tests ; *Drug Resistance, Bacterial ; Female ; *Genes, Bacterial ; Genotype ; Hospitals ; Humans ; Infant ; Iran ; Male ; Middle Aged ; Polymerase Chain Reaction ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification/*physiology ; Young Adult ; }, abstract = {BACKGROUND: Biofilm produced from Pseudomonas aeruginosa is the cause of infection induced by contact lenses, trauma and post-surgery infection. The aim of this study was to evaluate biofilm formation and the presence of the genes ndvB and tssC1 in ocular infection isolates of P. aeruginosa.

METHODS: A total of 92 P. aeruginosa strains were collected from patients with ocular infection referred to Farabi Hospital between March 2014 and July 2015. Antibiotic susceptibility patterns were evaluated by the agar disc-diffusion method according to CLSI guidelines. PCR assays were used to detect ndvB and tssC1, genes associated with resistance in biofilm-producing P. aeruginosa isolates. Biofilm formation ability was examined by crystal violet microtitre plate assay.

RESULTS: During the period of study, 92 P. aeruginosa were isolated from ocular infections including keratitis (n=84) and endophthalmitis (n=8). The highest resistance rates were seen against colistin (57.6 %) and gentamicin (50 %) and the lowest resistance rates were seen against imipenem (3.3 %), aztreonam (4.3 %), piperacillin-tazobactam (4.3 %), ceftazidime (4.3 %) and ciprofloxacin (5.4 %). Biofilm production ability was found in 100 % of the isolates. PCR assays showed that of the 92 P. aeruginosa isolates, 96.7 and 90.2 % harboured the genes ndvB and tssC1, respectively.

CONCLUSIONS: Our results showed a considerable ability of biofilm production, as well as the occurrence of biofilm-specific antimicrobial resistance genes (ndvB and tssC1), in P. aeruginosa isolates from ocular infections in Farabi Hospital.}, } @article {pmid28721252, year = {2016}, author = {Lim, CP and Mai, PNQ and Roizman Sade, D and Lam, YC and Cohen, Y}, title = {Biofilm development of an opportunistic model bacterium analysed at high spatiotemporal resolution in the framework of a precise flow cell.}, journal = {NPJ biofilms and microbiomes}, volume = {2}, number = {}, pages = {16023}, pmid = {28721252}, issn = {2055-5008}, abstract = {Life of bacteria is governed by the physical dimensions of life in microscales, which is dominated by fast diffusion and flow at low Reynolds numbers. Microbial biofilms are structurally and functionally heterogeneous and their development is suggested to be interactively related to their microenvironments. In this study, we were guided by the challenging requirements of precise tools and engineered procedures to achieve reproducible experiments at high spatial and temporal resolutions. Here, we developed a robust precise engineering approach allowing for the quantification of real-time, high-content imaging of biofilm behaviour under well-controlled flow conditions. Through the merging of engineering and microbial ecology, we present a rigorous methodology to quantify biofilm development at resolutions of single micrometre and single minute, using a newly developed flow cell. We designed and fabricated a high-precision flow cell to create defined and reproducible flow conditions. We applied high-content confocal laser scanning microscopy and developed image quantification using a model biofilm of a defined opportunistic strain, Pseudomonas putida OUS82. We observed complex patterns in the early events of biofilm formation, which were followed by total dispersal. These patterns were closely related to the flow conditions. These biofilm behavioural phenomena were found to be highly reproducible, despite the heterogeneous nature of biofilm.}, } @article {pmid28721241, year = {2016}, author = {Seghal Kiran, G and Priyadharshini, S and Dobson, ADW and Gnanamani, E and Selvin, J}, title = {Degradation intermediates of polyhydroxy butyrate inhibits phenotypic expression of virulence factors and biofilm formation in luminescent Vibrio sp. PUGSK8.}, journal = {NPJ biofilms and microbiomes}, volume = {2}, number = {}, pages = {16002}, pmid = {28721241}, issn = {2055-5008}, abstract = {Luminescent vibrios are ubiquitous in the marine environment and are the causative agents of vibriosis and mass mortality in many aquatic animals. In aquatic environments, treatments cannot be limited to the diseased population alone, therefore treatment of the entire aquatic system is the only possible approach. Thus, the use of antibiotics to treat part of the infected animals requires a dose based on the entire biomass, which results in the treatment of uninfected animals as well as non-target normal microbial flora. A treatment method based on anti-virulence or quorum quenching has recently been proposed as an effective treatment strategy for aquatic animals. Polyhydroxy butyrates (PHB) are bacterial storage molecules, which accumulate in cells under nutritional stress. The degradation of PHB releases short-chain β-hydroxy butyric acid, which may act as anti-infective molecule. To date, there is very limited information on the potential anti-infective and anti-virulence mechanisms involving PHB. In this study, we aim to examine the effect of PHB on inhibition of the virulence cascade of Vibrio such as biofilm formation, luminescence, motility behaviour, haemolysin and quorum sensing. A luminescent Vibrio PUGSK8, tentatively identified as Vibrio campbellii PUGSK8 was tested in vitro for production of extracellular virulence factors and then established as a potential shrimp pathogen based on in vivo challenge experiments. The ability of Vibrio PUGSK8 to form biofilms and the effect of PHB on biofilm formation was tested in a 96-well microtitre-plate assay system. The motility behaviour of Vibrio PUGSK8 was evaluated using twitching, swimming and swarming plate assays. Reporter strains such as Chromobacterium violaceum CV026 and Agrobacterium tumefaciens were used to detect quorum-sensing molecules. Gas chromatography-mass spectrometry spectral analysis was performed to elucidate the fragmentation pattern and structure of N-hexanoyl homoserine lactone. PHB depolymerase activity in Vibrio PUGSK8 was quantified as the amount of the enzyme solution to hydrolyse 1 μg of PHB per min. An in vivo challenge experiment was performed using a gnotobiotic Artemia assay. Of the 27 isolates tested, the Vibrio PUGSK8 strain was selected for target-specific assays based on the high intensity of luminescence and production of virulence factors. The virulence cascade detected in Vibrio PUGSK8 include luminescence, motility behaviour, biofilm formation, quorum sensing and haemolysin production. Thus inhibition/degradation of the virulence cascade would be an effective approach to contain Vibrio infections in aquatic animals. In this report, we demonstrate that the degradation intermediate of PHB effectively inhibits biofilm formation, luminescence, motility behaviour, haemolysin production and the N-acyl-homoserine lactone (AHL)-mediated quorum-sensing pathway in PUGSK8. Interestingly, the growth of Vibrio PUGSK8 remains unaffected in the presence of PHB, with PHB degradation being detected in the media. PHB depolymerase activity in Vibrio PUGSK8 results in the release of degradation intermediates include a short-chain β-hydroxy butyric acid, which inhibits the virulence cascade in Vibrio PUGSK8. Thus, a molecule that targets quorum sensing and the virulence cascade and which is species/strain-specific could prove to be an effective alternative to antimicrobial agents to control the pathogenesis of Vibrio, and thereby help to contain Vibrio outbreaks in aquatic systems.}, } @article {pmid28720810, year = {2017}, author = {Hashem, YA and Amin, HM and Essam, TM and Yassin, AS and Aziz, RK}, title = {Biofilm formation in enterococci: genotype-phenotype correlations and inhibition by vancomycin.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5733}, pmid = {28720810}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Egypt ; Enterococcus/*drug effects/genetics/isolation & purification/*physiology ; Genes, Bacterial ; *Genetic Association Studies ; Genotype ; Gram-Positive Bacterial Infections/microbiology ; Hospitals ; Humans ; Polymerase Chain Reaction ; Vancomycin/*pharmacology ; Virulence Factors/genetics ; }, abstract = {Enterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution in enterococcal genomes were identified, and the differentiating virulence genes were screened by polymerase chain reaction (PCR) in 31 of the clinical isolates. We found that detection of gelE in Enterococcus faecalis is not sufficient to predict gelatinase activity unless fsrAB, or fsrB alone, is PCR-positive (P = 0.0026 and 0.0012, respectively). We also found that agg is significantly enriched in isolates with medium and strong biofilm formation ability (P = 0.0026). Additionally, vancomycin, applied at sub minimal inhibitory concentrations, inhibited biofilm in four out of five strong biofilm-forming isolates. In conclusion, we suggest using agg and fsrB genes, together with the previously established gelE, for better prediction of biofilm strength and gelatinase activity, respectively. Future studies should explore the mechanism of biofilm inhibition by vancomycin and its possible use for antivirulence therapy.}, } @article {pmid28720732, year = {2017}, author = {Orazi, G and O'Toole, GA}, title = {Pseudomonas aeruginosa Alters Staphylococcus aureus Sensitivity to Vancomycin in a Biofilm Model of Cystic Fibrosis Infection.}, journal = {mBio}, volume = {8}, number = {4}, pages = {}, pmid = {28720732}, issn = {2150-7511}, support = {P20 GM103413/GM/NIGMS NIH HHS/United States ; R37 AI083256/AI/NIAID NIH HHS/United States ; T32 AI007519/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Biological Factors/metabolism ; Cells, Cultured ; Cystic Fibrosis/*microbiology ; Humans ; Hypoxia ; *Microbial Interactions ; Models, Biological ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*drug effects/physiology ; Vancomycin/*pharmacology ; }, abstract = {The airways of cystic fibrosis (CF) patients have thick mucus, which fosters chronic, polymicrobial infections. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients. In this study, we tested whether P. aeruginosa influences the susceptibility of S. aureus to frontline antibiotics used to treat CF lung infections. Using our in vitro coculture model, we observed that addition of P. aeruginosa supernatants to S. aureus biofilms grown either on epithelial cells or on plastic significantly decreased the susceptibility of S. aureus to vancomycin. Mutant analyses showed that 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), a component of the P. aeruginosa Pseudomonas quinolone signal (PQS) system, protects S. aureus from the antimicrobial activity of vancomycin. Similarly, the siderophores pyoverdine and pyochelin also contribute to the ability of P. aeruginosa to protect S. aureus from vancomycin, as did growth under anoxia. Under our experimental conditions, HQNO, P. aeruginosa supernatant, and growth under anoxia decreased S. aureus growth, likely explaining why this cell wall-targeting antibiotic is less effective. P. aeruginosa supernatant did not confer additional protection to slow-growing S. aureus small colony variants. Importantly, P. aeruginosa supernatant protects S. aureus from other inhibitors of cell wall synthesis as well as protein synthesis-targeting antibiotics in an HQNO- and siderophore-dependent manner. We propose a model whereby P. aeruginosa causes S. aureus to shift to fermentative growth when these organisms are grown in coculture, leading to reduction in S. aureus growth and decreased susceptibility to antibiotics targeting cell wall and protein synthesis.IMPORTANCE Cystic fibrosis (CF) lung infections are chronic and difficult to eradicate. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most prevalent respiratory pathogens in CF patients and are associated with poor patient outcomes. Both organisms adopt a biofilm mode of growth, which contributes to high tolerance to antibiotic treatment and the recalcitrant nature of these infections. Here, we show that P. aeruginosa exoproducts decrease the sensitivity of S. aureus biofilm and planktonic populations to vancomycin, a frontline antibiotic used to treat methicillin-resistant S. aureus in CF patients. P. aeruginosa also protects S. aureus from other cell wall-active antibiotics as well as various classes of protein synthesis inhibitors. Thus, interspecies interactions can have dramatic and unexpected consequences on antibiotic sensitivity. This study underscores the potential impact of interspecies interactions on antibiotic efficacy in the context of complex, polymicrobial infections.}, } @article {pmid28720276, year = {2018}, author = {Zhu, N and Zhang, J and Tang, J and Zhu, Y and Wu, Y}, title = {Arsenic removal by periphytic biofilm and its application combined with biochar.}, journal = {Bioresource technology}, volume = {248}, number = {Pt B}, pages = {49-55}, doi = {10.1016/j.biortech.2017.07.026}, pmid = {28720276}, issn = {1873-2976}, mesh = {*Arsenic ; Biofilms ; *Charcoal ; Wastewater ; }, abstract = {A biochar and periphyton-based system (BPS) comprising of a biochar column and a periphyton bioreactor was designed to avoid the toxicity issue associated with removing As(III) from wastewater. Results showed that the periphyton can grow when As(III) is less than 5.0mgL[-1]. The BPS obtained a high As(III) removal rate (∼90.2-95.4%) at flow rate=1.0mLmin[-1] and initial concentration of As(III)=2.0mgL[-1]. About 60% of the As(III) was pre-treated (adsorbed) in the biochar column and the removal of the remaining As(III) was attributed to the periphyton bioreactor. The As(III) removal process by periphytic biofilm in the initial stage fits a pseudo-second-kinetic model. The calcite in the periphytic biofilm surfaces and the OH and CO groups were responsible for the As(III) removal. This study indicates the feasibility of the BPS for As(III) removal in practice.}, } @article {pmid28719849, year = {2017}, author = {Pozo, G and Lu, Y and Pongy, S and Keller, J and Ledezma, P and Freguia, S}, title = {Selective cathodic microbial biofilm retention allows a high current-to-sulfide efficiency in sulfate-reducing microbial electrolysis cells.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {118}, number = {}, pages = {62-69}, doi = {10.1016/j.bioelechem.2017.07.001}, pmid = {28719849}, issn = {1878-562X}, mesh = {Bacteria/*metabolism ; *Biofilms ; *Electric Conductivity ; Electrodes ; Electrolysis/*instrumentation ; Hydrogen-Ion Concentration ; Nanotubes, Carbon/chemistry ; Sulfates/chemistry/*metabolism ; Sulfides/chemistry/*metabolism ; }, abstract = {Selective microbial retention is of paramount importance for the long-term performance of cathodic sulfate reduction in microbial electrolysis cells (MECs) due to the slow growth rate of autotrophic sulfate-reducing bacteria. In this work, we investigate the biofilm retention and current-to-sulfide conversion efficiency using carbon granules (CG) or multi-wall carbon nanotubes deposited on reticulated vitreous carbon (MWCNT-RVC) as electrode materials. For ~2months, the MECs were operated at sulfate loading rates of 21 to 309gSO4 -S/m[2]/d. Although MWCNT-RVC achieved a current density of 57±11A/m[2], greater than the 32±9A/m[2] observed using CG, both materials exhibited similar sulfate reduction rates (SRR), with MWCNT-RVC reaching 104±16gSO4 -S/m[2]/d while 110±13gSO4 -S/m[2]/d were achieved with CG. Pyrosequencing analysis of the 16S rRNA at the end of experimentation revealed a core community dominated by Desulfovibrio (28%), Methanobacterium (19%) and Desulfomicrobium (14%), on the MWCNT-RVC electrodes. While a similar Desulfovibrio relative abundance of 29% was found in CG-biofilms, Desulfomicrobium was found to be significantly less abundant (4%) and Methanobacterium practically absent (0.2%) on CG electrodes. Surprisingly, our results show that CG can achieve higher current-to-sulfide efficiencies at lower power consumption than the nano-modified three-dimensional MWCNT-RVC.}, } @article {pmid28719354, year = {2017}, author = {Raei, P and Pourlak, T and Memar, MY and Alizadeh, N and Aghamali, M and Zeinalzadeh, E and Asgharzadeh, M and Kafil, HS}, title = {Thymol and carvacrol strongly inhibit biofilm formation and growth of carbapenemase-producing Gram negative bacilli.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {63}, number = {5}, pages = {108-112}, doi = {10.14715/cmb/2017.63.5.20}, pmid = {28719354}, issn = {1165-158X}, mesh = {Bacillus/*drug effects/*growth & development ; Bacterial Proteins/*biosynthesis ; Biofilms/drug effects/*growth & development ; Cymenes ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Thymol/*pharmacology ; beta-Lactamases/*biosynthesis ; }, abstract = {Discovery of novel drugs with new mechanisms of action and without cross-reaction with current therapeutic agents is crucial in the management of infections caused by multi-drug resistant (MDR) bacteria. The aim of the present study was to investigate effects of carvacrol and thymol on biofilm formation and antimicrobial activity against different carbapenemase-producing Gram negative bacilli. The antimicrobial and antibiofilm effect of thymol and carvacrol was investigated against strains harboring different genes related to carbapenemase resistance. Antimicrobial resistance was examined by an agar dilution method and antibiofilm effect was evaluated by microtiter plate assay and staining by crystal violet. Thymol and carvacrol had antibacterial effects ranging from 200-1600 μg/mL and 62-250 μg/mL respectively, and antibiofilm effect from 125-500 and 400-1600 μg/mL respectively. Seoul imipenemase- (SIM) producing isolates had the highest sensitivity, and NDM (New Delhi metallo-beta-lactamase) producing isolates had the lowest sensitivity to these components. Findings of the present study indicated a potential role of carvacrol and thymol in controlling carbapenemase-producing gram negative bacterial infections. These findings helped to develop herbal drugs for replacing antibiotics. In addition, their antibiofilm effects showed that carvacrol and thymol inhibit biofilm formation of carbapenemase-producing strains.}, } @article {pmid28719346, year = {2017}, author = {Akbari Aghdam, M and Soroush Barhaghi, MH and Aghazadeh, M and Jafari, F and Beomide Hagh, M and Haghdoost, M and Memar, MY and Ahangarzadeh Rezaee, M and Samadi Kafil, H}, title = {Virulence genes in biofilm producer Enterococcus faecalis isolates from root canal infections.}, journal = {Cellular and molecular biology (Noisy-le-Grand, France)}, volume = {63}, number = {5}, pages = {55-59}, doi = {10.14715/cmb/2017.63.5.11}, pmid = {28719346}, issn = {1165-158X}, mesh = {Biofilms/*growth & development ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*genetics/isolation & purification/*pathogenicity/physiology ; *Genes, Bacterial ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; Virulence/genetics ; }, abstract = {Enterococcus faecalis is occurring in opportunistic infections involving the oral cavity. This study aimed to evaluate the presence of E. faecalis virulence genes in dental root canal isolates recovered from advanced chronic periodontitis patients. One hundred E. faecalis isolated from dental root canal during July 2015 to Oct 2016. After analysis of biofilm formation by the semi-quantitative determination in 96-well flat bottom polystyrene plates, the presence of asa, esp, efaA, ace, ebpR, gel and hyl gene were studied by PCR. Gelatinase and hemolytic activity were detected by phenotypic methods. Ninety-one percent of isolates had ebpR gene, 85% ace, 82% efaA, 81% gel, 56% esp, 33% asa1, 2% hyl and 0% cyl gene. Evaluation of biofilm formation by microtiter plate method presented 49% of the isolates as strong biofilm producer, 42% displayed moderate biofilm formation, and 10 % weak or no biofilm was observed. asa1, efaA, esp, and ebpR positive isolates had significantly higher biofilm formation than negative isolates, while no significant differences were found when comparing ace-positive and - negative isolates. Present study showed that the ace genes do not seem to be necessary nor sufficient for the production of biofilm in Enterococcus faecalis but the presence of asa1, efaA, esp, and ebpR correlates with increased biofilm formation of dental root canal isolates.}, } @article {pmid28717038, year = {2017}, author = {Xiong, YQ and Estellés, A and Li, L and Abdelhady, W and Gonzales, R and Bayer, AS and Tenorio, E and Leighton, A and Ryser, S and Kauvar, LM}, title = {A Human Biofilm-Disrupting Monoclonal Antibody Potentiates Antibiotic Efficacy in Rodent Models of both Staphylococcus aureus and Acinetobacter baumannii Infections.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {10}, pages = {}, pmid = {28717038}, issn = {1098-6596}, support = {R44 AI120425/AI/NIAID NIH HHS/United States ; SB1 AI120425/AI/NIAID NIH HHS/United States ; }, mesh = {Acinetobacter Infections/*drug therapy ; Acinetobacter baumannii/*drug effects ; Animals ; Anti-Bacterial Agents/*therapeutic use ; Antibodies, Monoclonal/*therapeutic use ; Antibodies, Monoclonal, Humanized ; Aortic Valve/microbiology ; Biofilms/*drug effects/growth & development ; Drug Therapy, Combination ; Endocarditis/*drug therapy/microbiology ; Epitopes/immunology ; Female ; Humans ; Imipenem/therapeutic use ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Mice, Inbred BALB C ; Rats ; Rats, Sprague-Dawley ; Staphylococcal Infections/*drug therapy ; Vancomycin/therapeutic use ; }, abstract = {Many serious bacterial infections are antibiotic refractory due to biofilm formation. A key structural component of biofilm is extracellular DNA, which is stabilized by bacterial proteins, including those from the DNABII family. TRL1068 is a high-affinity human monoclonal antibody against a DNABII epitope conserved across both Gram-positive and Gram-negative bacterial species. In the present study, the efficacy of TRL1068 for the disruption of biofilm was demonstrated in vitro in the absence of antibiotics by scanning electron microscopy. The in vivo efficacy of this antibody was investigated in a well-characterized catheter-induced aortic valve infective endocarditis model in rats infected with a methicillin-resistant Staphylococcus aureus (MRSA) strain with the ability to form thick biofilms, obtained from the blood of a patient with persistent clinical infection. Animals were treated with vancomycin alone or in combination with TRL1068. MRSA burdens in cardiac vegetations and within intracardiac catheters, kidneys, spleen, and liver showed significant reductions in the combination arm versus vancomycin alone (P < 0.001). A trend toward mortality reduction was also observed (P = 0.09). In parallel, the in vivo efficacy of TRL1068 against a multidrug-resistant clinical Acinetobacter baumannii isolate was explored by using an established mouse model of skin and soft tissue catheter-related biofilm infection. Catheter segments infected with A. baumannii were implanted subcutaneously into mice; animals were treated with imipenem alone or in combination with TRL1068. The combination showed a significant reduction of catheter-adherent bacteria versus the antibiotic alone (P < 0.001). TRL1068 shows excellent promise as an adjunct to standard-of-care antibiotics for a broad range of difficult-to-treat bacterial infections.}, } @article {pmid28716362, year = {2018}, author = {Horng, YT and Wang, CJ and Chung, WT and Chao, HJ and Chen, YY and Soo, PC}, title = {Phosphoenolpyruvate phosphotransferase system components positively regulate Klebsiella biofilm formation.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {51}, number = {2}, pages = {174-183}, doi = {10.1016/j.jmii.2017.01.007}, pmid = {28716362}, issn = {1995-9133}, mesh = {Bacterial Capsules/*metabolism ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cell-Free Nucleic Acids/genetics ; Citric Acid Cycle/genetics ; Equipment and Supplies/microbiology ; Extracellular Matrix/genetics/metabolism ; Genome, Bacterial/genetics ; Klebsiella pneumoniae/*genetics/growth & development/*pathogenicity ; Phosphoenolpyruvate Sugar Phosphotransferase System/*genetics/metabolism ; Polysaccharides, Bacterial/*metabolism ; Quorum Sensing/genetics ; }, abstract = {BACKGROUND/PURPOSE: Klebsiella pneumoniae is one of the leading causes of device-related infections (DRIs), which are associated with attachment of bacteria to these devices to form a biofilm. The latter is composed of not only bacteria but also extracellular polymeric substances (EPSes) consisting of extracellular DNAs, polysaccharides, and other macromolecules. The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) regulates diverse processes of bacterial physiology. In the genome of K. pneumoniae MGH 78578, we found an uncharacterized enzyme II complex homolog of PTS: KPN00353 (EIIA homolog), KPN00352 (EIIB homolog), and KPN00351 (EIIC homolog). The aim of this study was to characterize the potential physiological role of KPN00353, KPN00352, and KPN00351 in biofilm formation by K. pneumoniae.

METHODS/RESULTS: We constructed the PTS mutants and recombinant strains carrying the gene(s) of PTS. The recombinant K. pneumoniae strain overexpressing KPN00353-KPN00352-KPN00351 produced more extracellular matrix than did the vector control according to transmission and scanning electron microscopy. Judging by quantification of biofilm formation, of extracellular DNA (eDNA), and of capsular polysaccharide, the recombinant strain overexpressing KPN00353-KPN00352-KPN00351 produced more biofilm and capsular polysaccharide after overnight culture and more eDNA in the log phase as compared to the vector control.

CONCLUSION: The genes, KPN00353-KPN00352-KPN00351, encode a putative enzyme II complex in PTS and positively regulate biofilm formation by enhancing production of eDNA and capsular polysaccharide in K. pneumoniae. Five proteins related to chaperones, to the citric acid cycle, and to quorum sensing are upregulated by the KPN00353-KPN00352-KPN00351 system.}, } @article {pmid28715697, year = {2017}, author = {Zhao, J and Feng, L and Yang, G and Dai, J and Mu, J}, title = {Development of simultaneous nitrification-denitrification (SND) in biofilm reactors with partially coupled a novel biodegradable carrier for nitrogen-rich water purification.}, journal = {Bioresource technology}, volume = {243}, number = {}, pages = {800-809}, doi = {10.1016/j.biortech.2017.06.127}, pmid = {28715697}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; *Denitrification ; Nitrification ; Nitrogen ; Waste Disposal, Fluid ; *Water Purification ; }, abstract = {Development of simultaneous nitrification-denitrification (SND) is a promising approach for nitrogen-rich water purification. Coupling biofilm reactors with novel biodegradable carrier of Pumelo Peel (PP) and various conventional plastic fillers (polyurethane filler, SPR-1 suspension filler, TA-II elastic filler and sphere filler) were examined to achieve SND in this study. Results represented that partially coupled with PP could achieve highly efficient SND. Optimal performance appealed in a bioreactor of coupling PP and SPR-1filler with ammonia and total nitrogen removal efficiencies of 96.8±4.0% and 78.9±9.5%, respectively, as well as low effluent CODMn of 1.85±0.86mgL[-1]. Notably, PP and conventional plastic filler played obviously different roles in combined bioreactor system. Microbial analysis suggested that dominant genera were Thiothrix, Gemmata, unclassified comanonadaceae, unclassified Rhizobiales, Salipiger, Chloronema and Klebsiella in optimal combined bioreactor, which indicated novel co-existence of heterotrophic nitrification, solid-phase, non-solid-phase heterotrophic and sulfur-based autotrophic denitrification for achieving efficient SND.}, } @article {pmid28715664, year = {2017}, author = {Jia, R and Yang, D and Xu, D and Gu, T}, title = {Electron transfer mediators accelerated the microbiologically influence corrosion against carbon steel by nitrate reducing Pseudomonas aeruginosa biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {118}, number = {}, pages = {38-46}, doi = {10.1016/j.bioelechem.2017.06.013}, pmid = {28715664}, issn = {1878-562X}, mesh = {*Biofilms ; Carbon/*chemistry ; Cell Count ; Corrosion ; Electrochemistry ; Electron Transport ; Electrons ; Kinetics ; Nitrates/*metabolism ; Plankton/microbiology ; Pseudomonas aeruginosa/cytology/*metabolism/physiology ; Steel/*chemistry ; }, abstract = {Electron transfer is a rate-limiting step in microbiologically influenced corrosion (MIC) caused by microbes that utilize extracellular electrons. Cross-cell wall electron transfer is necessary to transport the electrons released from extracellular iron oxidation into the cytoplasm of cells. Electron transfer mediators were found to accelerate the MIC caused by sulfate reducing bacteria. However, there is no publication in the literature showing the effect of electron transfer mediators on MIC caused by nitrate reducing bacteria (NRB). This work demonstrated that the corrosion of anaerobic Pseudomonas aeruginosa (PAO1) grown as a nitrate reducing bacterium biofilm on C1018 carbon steel was enhanced by two electron transfer mediators, riboflavin and flavin adenine dinucleotide (FAD) separately during a 7-day incubation period. The addition of either 10ppm (w/w) (26.6μM) riboflavin or 10ppm (12.7μM) FAD did not increase planktonic cell counts, but they increased the maximum pit depth on carbon steel coupons considerably from 17.5μm to 24.4μm and 25.0μm, respectively. Riboflavin and FAD also increased the specific weight loss of carbon steel from 2.06mg/cm[2] to 2.34mg/cm[2] and 2.61mg/cm[2], respectively. Linear polarization resistance, electrochemical impedance spectroscopy and potentiodynamic polarization curves all corroborated the pitting and weight loss data.}, } @article {pmid28715508, year = {2017}, author = {Costa Oliveira, BE and Cury, JA and Ricomini Filho, AP}, title = {Biofilm extracellular polysaccharides degradation during starvation and enamel demineralization.}, journal = {PloS one}, volume = {12}, number = {7}, pages = {e0181168}, pmid = {28715508}, issn = {1932-6203}, mesh = {Analysis of Variance ; Animals ; *Biofilms/growth & development ; Calcium/metabolism ; Cattle ; Dental Enamel/metabolism/*microbiology ; Extracellular Space/metabolism/microbiology ; Fructose/pharmacology ; Glucose/pharmacology ; Hardness ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Incisor/metabolism/microbiology ; Microscopy, Confocal ; Polysaccharides/*metabolism ; Streptococcus mutans/growth & development/*metabolism ; Sucrose/pharmacology ; Tooth Demineralization/metabolism/*microbiology ; }, abstract = {This study was conducted to evaluate if extracellular polysaccharides (EPS) are used by Streptococcus mutans (Sm) biofilm during night starvation, contributing to enamel demineralization increasing occurred during daily sugar exposure. Sm biofilms were formed during 5 days on bovine enamel slabs of known surface hardness (SH). The biofilms were exposed to sucrose 10% or glucose + fructose 10.5% (carbohydrates that differ on EPS formation), 8x/day but were maintained in starvation during the night. Biofilm samples were harvested during two moments, on the end of the 4th day and in the morning of the 5th day, conditions of sugar abundance and starvation, respectively. The slabs were also collected to evaluate the percentage of surface hardness loss (%SHL). The biofilms were analyzed for EPS soluble and insoluble and intracellular polysaccharides (IPS), viable bacteria (CFU), biofilm architecture and biomass. pH, calcium and acid concentration were determined in the culture medium. The data were analyzed by two-way ANOVA followed by Tukey's test or Student's t-test. The effect of the factor carbohydrate treatment for polysaccharide analysis was significant (p < 0.05) but not the harvest moment (p > 0.05). Larger amounts of soluble and insoluble EPS and IPS were formed in the sucrose group when compared to glucose + fructose group (p < 0.05), but they were not metabolized during starvation time (S-EPS, p = 0.93; I-EPS, p = 0.11; and IPS = 0.96). Greater enamel %SHL was also found for the sucrose group (p < 0.05) but the demineralization did not increase during starvation (p = 0.09). In conclusion, the findings suggest that EPS metabolization by S. mutans during night starvation do not contribute to increase enamel demineralization occurred during the daily abundance of sugar.}, } @article {pmid28715477, year = {2017}, author = {Mukherjee, S and Moustafa, D and Smith, CD and Goldberg, JB and Bassler, BL}, title = {The RhlR quorum-sensing receptor controls Pseudomonas aeruginosa pathogenesis and biofilm development independently of its canonical homoserine lactone autoinducer.}, journal = {PLoS pathogens}, volume = {13}, number = {7}, pages = {e1006504}, pmid = {28715477}, issn = {1553-7374}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Female ; *Gene Expression Regulation, Bacterial ; Humans ; Mice ; Mice, Inbred BALB C ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/*pathogenicity/*physiology ; Quorum Sensing ; Regulon ; Virulence ; }, abstract = {Quorum sensing (QS) is a bacterial cell-to-cell communication process that relies on the production, release, and response to extracellular signaling molecules called autoinducers. QS controls virulence and biofilm formation in the human pathogen Pseudomonas aeruginosa. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, which produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Here, we use biofilm analyses, reporter assays, RNA-seq studies, and animal infection assays to show that RhlR directs both RhlI-dependent and RhlI-independent regulons. In the absence of RhlI, RhlR controls the expression of genes required for biofilm formation as well as genes encoding virulence factors. Consistent with these findings, ΔrhlR and ΔrhlI mutants have radically different biofilm phenotypes and the ΔrhlI mutant displays full virulence in animals whereas the ΔrhlR mutant is attenuated. The ΔrhlI mutant cell-free culture fluids contain an activity that stimulates RhlR-dependent gene expression. We propose a model in which RhlR responds to an alternative ligand, in addition to its canonical C4-homoserine lactone autoinducer. This alternate ligand promotes a RhlR-dependent transcriptional program in the absence of RhlI.}, } @article {pmid28714256, year = {2017}, author = {Chen, R and Lv, R and Xiao, L and Wang, M and Du, Z and Tan, Y and Cui, Y and Yan, Y and Luo, Y and Yang, R and Song, Y}, title = {A1S_2811, a CheA/Y-like hybrid two-component regulator from Acinetobacter baumannii ATCC17978, is involved in surface motility and biofilm formation in this bacterium.}, journal = {MicrobiologyOpen}, volume = {6}, number = {5}, pages = {}, pmid = {28714256}, issn = {2045-8827}, mesh = {Acinetobacter baumannii/*physiology/ultrastructure ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Gene Order ; Histidine Kinase/chemistry/*genetics/*metabolism ; Lactones/metabolism ; Operon ; Phenotype ; *Quorum Sensing ; }, abstract = {Two-component systems in Acinetobacter baumannii are associated with its virulence, drug resistance, motility, biofilm formation, and other characteristics. In this study, we used RecAb , a genetic engineering method, to investigate the function of A1S_2811 in A. baumannii strain ATCC17978. A1S_2811, a hypothetical hybrid sensor histidine kinase/response regulator, has four histidine-containing phosphotransfer domains, a CheA-like regulatory domain, and a CheY-like receiver domain at its C terminus. Compared with the ATCC17978 strain, both surface motility and biofilm formation at the gas-liquid interface decreased significantly in the A1S_2811 knock-out strain. The number of pilus-like structures and the amount of extrapolymeric substances on the cell surface also decreased in the A1S_2811 null strain. Transcription of abaI, which encodes an N-acylhomoserine lactone synthase in A. baumannii , decreased significantly in the A1S_2811 null strain, and supplementation with synthetic N-(3-oxodecanoyl) homoserine-l-lactone rescued the surface motility and biofilm formation phenotype in the null mutant. We speculate that A1S_2811 regulates surface motility and biofilm formation, not by regulating type IV pili-associated genes expression, but by regulating the chaperone/usher pili-associated csuA/ABCDE operon and the AbaI-dependent quorum-sensing pathway-associated A1S_0112-0119 operon instead.}, } @article {pmid28713361, year = {2017}, author = {Yang, L and Li, S and Qin, X and Jiang, G and Chen, J and Li, B and Yao, X and Liang, P and Zhang, Y and Ding, W}, title = {Exposure to Umbelliferone Reduces Ralstonia solanacearum Biofilm Formation, Transcription of Type III Secretion System Regulators and Effectors and Virulence on Tobacco.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1234}, pmid = {28713361}, issn = {1664-302X}, abstract = {Ralstonia solanacearum is one of the most devastating phytopathogens and causes bacterial wilt, which leads to severe economic loss due to its worldwide distribution and broad host range. Certain plant-derived compounds (PDCs) can impair bacterial virulence by suppressing pathogenic factors of R. solanacearum. However, the inhibitory mechanisms of PDCs in bacterial virulence remain largely unknown. In this study, we screened a library of coumarins and derivatives, natural PDCs with fused benzene and α-pyrone rings, for their effects on expression of the type III secretion system (T3SS) of R. solanacearum. Here, we show that umbelliferone (UM), a 7-hydroxycoumarin, suppressed T3SS regulator gene expression through HrpG-HrpB and PrhG-HrpB pathways. UM decreased gene expression of six type III effectors (RipX, RipD, RipP1, RipR, RipTAL, and RipW) of 10 representative effector genes but did not alter T2SS expression. In addition, biofilm formation of R. solanacearum was significantly reduced by UM, though swimming activity was not affected. We then observed that UM suppressed the wilting disease process by reducing colonization and proliferation in tobacco roots and stems. In summary, the findings reveal that UM may serve as a plant-derived inhibitor to manipulate R. solanacearum T3SS and biofilm formation, providing proof of concept that these key virulence factors are potential targets for the integrated control of bacterial wilt.}, } @article {pmid28713356, year = {2017}, author = {Pires, DP and Dötsch, A and Anderson, EM and Hao, Y and Khursigara, CM and Lam, JS and Sillankorva, S and Azeredo, J}, title = {A Genotypic Analysis of Five P. aeruginosa Strains after Biofilm Infection by Phages Targeting Different Cell Surface Receptors.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1229}, pmid = {28713356}, issn = {1664-302X}, abstract = {Antibiotic resistance constitutes one of the most serious threats to the global public health and urgently requires new and effective solutions. Bacteriophages are bacterial viruses increasingly recognized as being good alternatives to traditional antibiotic therapies. In this study, the efficacy of phages, targeting different cell receptors, against Pseudomonas aeruginosa PAO1 biofilm and planktonic cell cultures was evaluated over the course of 48 h. Although significant reductions in the number of viable cells were achieved for both cases, the high level of adaptability of the bacteria in response to the selective pressure caused by phage treatment resulted in the emergence of phage-resistant variants. To further investigate the genetic makeup of phage-resistant variants isolated from biofilm infection experiments, some of these bacteria were selected for phenotypic and genotypic characterization. Whole genome sequencing was performed on five phage-resistant variants and all of them carried mutations affecting the galU gene as well as one of pil genes. The sequencing analysis further revealed that three of the P. aeruginosa PAO1 variants carry large deletions (>200 kbp) in their genomes. Complementation of the galU mutants with wild-type galU in trans restored LPS expression on the bacterial cell surface of these bacterial strains and rendered the complemented strains to be sensitive to phages. This provides unequivocal evidence that inactivation of galU function was associated with resistance to the phages that uses LPS as primary receptors. Overall, this work demonstrates that P. aeruginosa biofilms can survive phage attack and develop phage-resistant variants exhibiting defective LPS production and loss of type IV pili that are well adapted to the biofilm mode of growth.}, } @article {pmid28710947, year = {2017}, author = {Piercey, MJ and Ells, TC and Macintosh, AJ and Truelstrup Hansen, L}, title = {Variations in biofilm formation, desiccation resistance and Benzalkonium chloride susceptibility among Listeria monocytogenes strains isolated in Canada.}, journal = {International journal of food microbiology}, volume = {257}, number = {}, pages = {254-261}, doi = {10.1016/j.ijfoodmicro.2017.06.025}, pmid = {28710947}, issn = {1879-3460}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Base Sequence ; Benzalkonium Compounds/*pharmacology ; Biofilms/drug effects/*growth & development ; Canada ; DNA, Bacterial/genetics ; *Desiccation ; Drug Tolerance/genetics/physiology ; Food Contamination/*analysis ; Food Handling/methods ; Humans ; Listeria monocytogenes/classification/*drug effects/*growth & development ; Sequence Analysis, DNA ; Stainless Steel/pharmacology ; }, abstract = {Listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. Survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure. The objectives of this research were to compare 14 L. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (BAC) sensitivity, desiccation resistance, and ability to form biofilm. Correlations were tested between those responses, and the presence of the SSI-1 (Stress Survival Islet) and LGI1/CC8 (Listeria Genomic Island 1 in a clonal complex 8 background) genetic markers. Genetic sequences from four strains representing different phenotypes were also probed for predicted amino acid differences in biofilm, desiccation, and membrane related genes. The water isolates were among the most desiccation susceptible strains, while strains exhibiting desiccation resistance harboured SSI-1 or both the SSI-1 and LGI1/CC8 markers. BAC resistance was greatest in planktonic LGI1/CC8 cells (relative to non-LGI1/CC8 cells), and higher BAC concentrations were also needed to inhibit the formation of biofilm by LGI1/CC8 strains during incubation for 48h and 6days compared to other strains. Formation of biofilm on stainless steel was not significantly (p>0.05) different among the strains. Analysis of genetic sequence data from desiccation and BAC sensitive (CP4 5-1, CP5 2-3, both from water), intermediate (Lm568, food) and desiccation and BAC resistant (08 5578, blood, human outbreak) strains led to the finding of amino acid differences in predicted functional protein domains in several biofilm, desiccation and peptidoglycan related genes (e.g., lmo0263, lmo0433, lmo0434, lmo0771, lmo0973, lmo1080, lmo1224, lmo1370, lmo1744, and lmo2558). Notably, the LGI1/CC8 strain 08-5578 had a frameshift mutation in lmo1370, a gene previously associated with desiccation resistance. In conclusion, the more desiccation and BAC resistant LGI1/CC8 isolates may pose a challenge for sanitation efforts.}, } @article {pmid28710559, year = {2017}, author = {Xiang, H and Cao, F and Ming, D and Zheng, Y and Dong, X and Zhong, X and Mu, D and Li, B and Zhong, L and Cao, J and Wang, L and Ma, H and Wang, T and Wang, D}, title = {Aloe-emodin inhibits Staphylococcus aureus biofilms and extracellular protein production at the initial adhesion stage of biofilm development.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {17}, pages = {6671-6681}, doi = {10.1007/s00253-017-8403-5}, pmid = {28710559}, issn = {1432-0614}, support = {2016YFD05013//The National Key Technology R&D Program/ ; 2016194//China Education Department of Jilin province science and technology research project of "13th Five-Year"/ ; }, mesh = {Anthraquinones/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/metabolism ; Biofilms/*drug effects/*growth & development ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/antagonists & inhibitors ; Staphylococcus aureus/*drug effects/physiology/ultrastructure ; }, abstract = {Staphylococcus aureus (S. aureus) biofilms are clinically serious and play a critical role in the persistence of chronic infections due to their ability to resist antibiotics. The inhibition of biofilm formation is viewed as a new strategy for the prevention of S. aureus infections. Here, we demonstrated that minimum inhibitory concentrations (MICs) of aloe-emodin exhibited no bactericidal activity against S. aureus but affected S. aureus biofilm development in a dose-dependent manner. Further studies indicated that aloe-emodin specifically inhibits the initial adhesion and proliferation stages of S. aureus biofilm development. Scanning electron microscopy (SEM) indicated that the S. aureus ATCC29213 biofilm extracellular matrix is mainly composed of protein. Laser scanning confocal microscope assays revealed that aloe-emodin treatment primarily inhibited extracellular protein production. Moreover, the Congo red assay showed that aloe-emodin also reduced the accumulation of polysaccharide intercellular adhesin (PIA) on the cell surface. These findings will provide new insights into the mode of action of aloe-emodin in the treatment of infections by S. aureus biofilms.}, } @article {pmid28709485, year = {2017}, author = {Ghosh, R and Das, S and Kela, H and De, A and Haldar, J and Maiti, PK}, title = {Biofilm colonization of Mycobacterium abscessus: New threat in hospital-acquired surgical site infection.}, journal = {The Indian journal of tuberculosis}, volume = {64}, number = {3}, pages = {178-182}, doi = {10.1016/j.ijtb.2016.11.013}, pmid = {28709485}, issn = {0019-5707}, mesh = {Biofilms/*growth & development ; Cross Infection/*microbiology/prevention & control ; Equipment Contamination/prevention & control ; Humans ; Infection Control/methods ; Laparoscopy/*adverse effects/instrumentation ; Mycobacterium Infections, Nontuberculous/*microbiology/prevention & control ; Mycobacterium abscessus/*isolation & purification ; Prospective Studies ; Surgical Wound Infection/*microbiology/prevention & control ; }, abstract = {INTRODUCTION: Rapidly growing non-tuberculous mycobacteria (NTM) are hazardous cause of post-operative soft tissue infection leading to nosocomial outbreaks following various surgical procedures, especially laparoscopic surgeries using heat sensitive, non-autoclavable surgical instruments.

METHODOLOGY: Surgery department of our hospital noticed increase in rate of post-laparoscopic abdominal port site infection (PSI) and informed the Microbiology Department. A prospective investigational study of defined cases with the aim of source tracing and formulation of infection control measures was initiated. Pus or wound scrapings were collected and processed for aerobic, anaerobic bacteria and Mycobacterium, both by staining and culture. Environmental samples were collected from laparoscopic instruments, and different parts of operation theatre (OT). Mycobacterial isolates were speciated by line probe assay. All the cases were treated with clarithromycin and ofloxacin±amikacin.

RESULTS: Among 15 cases of PSI, 11 patients had undergone laparoscopic cholecystectomy, 3 had laparoscopic mesh hernioplasty and one had laparoscopic orchidopexy. Of the 13 pus/discharge specimens examined, 11 revealed growth of NTM. All the isolates were identified as Mycobacterium abscessus by line probe assay. Scraping of biofilm from the disinfectant tray also produced growth of the same organism. Plastic trays used for disinfectants were replaced with metal trays and instructed to do mechanical scrubbing before autoclaving at regular interval. No similar PSI cases were notified after those measures were taken, till date.

CONCLUSIONS: This study has shown the need of culture and identification of pathogens causing persistent post surgical wound infections and illuminated importance of rapid source tracing in resource constraint situation which could control outbreak.}, } @article {pmid28709374, year = {2017}, author = {Gupta, D and Singh, A and Khan, AU}, title = {Nanoparticles as Efflux Pump and Biofilm Inhibitor to Rejuvenate Bactericidal Effect of Conventional Antibiotics.}, journal = {Nanoscale research letters}, volume = {12}, number = {1}, pages = {454}, pmid = {28709374}, issn = {1931-7573}, abstract = {The universal problem of bacterial resistance to antibiotic reflects a serious threat for physicians to control infections. Evolution in bacteria results in the development of various complex resistance mechanisms to neutralize the bactericidal effect of antibiotics, like drug amelioration, target modification, membrane permeability reduction, and drug extrusion through efflux pumps. Efflux pumps acquire a wide range of substrate specificity and also the tremendous efficacy for drug molecule extrusion outside bacterial cells. Hindrance in the functioning of efflux pumps may rejuvenate the bactericidal effect of conventional antibiotics. Efflux pumps also play an important role in the exclusion or inclusion of quorum-sensing biomolecules responsible for biofilm formation in bacterial cells. This transit movement of quorum-sensing biomolecules inside or outside the bacterial cells may get interrupted by impeding the functioning of efflux pumps. Metallic nanoparticles represent a potential candidate to block efflux pumps of bacterial cells. The application of nanoparticles as efflux pump inhibitors will not only help to revive the bactericidal effect of conventional antibiotics but will also assist to reduce biofilm-forming capacity of microbes. This review focuses on a novel and fascinating application of metallic nanoparticles in synergy with conventional antibiotics for efflux pump inhibition.}, } @article {pmid28709125, year = {2017}, author = {Verderosa, AD and de la Fuente-Núñez, C and Mansour, SC and Cao, J and Lu, TK and Hancock, REW and Fairfull-Smith, KE}, title = {Ciprofloxacin-nitroxide hybrids with potential for biofilm control.}, journal = {European journal of medicinal chemistry}, volume = {138}, number = {}, pages = {590-601}, doi = {10.1016/j.ejmech.2017.06.058}, pmid = {28709125}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line, Tumor ; Ciprofloxacin/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; HEK293 Cells ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Nitrogen Oxides/chemistry/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; Structure-Activity Relationship ; }, abstract = {As bacterial biofilms display extreme tolerance to conventional antibiotic treatments, it has become imperative to develop new antibacterial strategies with alternative mechanisms of action. Herein, we report the synthesis of a series of ciprofloxacin-nitroxide conjugates and their corresponding methoxyamine derivatives in high yield. This was achieved by linking various nitroxides or methoxyamines to the secondary amine of the piperazine ring of ciprofloxacin using amide bond coupling. Biological evaluation of the prepared compounds on preformed P. aeruginosa biofilms in flow cells revealed substantial dispersal with ciprofloxacin-nitroxide hybrid 25, and virtually complete killing and removal (94%) of established biofilms in the presence of ciprofloxacin-nitroxide hybrid 27. Compounds 25-28 were shown to be non-toxic in both human embryonic kidney 293 (HEK 293) cells and human muscle rhabdomyosarcoma (RD) cells at concentrations up to 40 μM. Significantly, these hybrids demonstrate the potential of antimicrobial-nitroxide agents to overcome the resistance of biofilms to antimicrobials via stimulation of biofilm dispersal or through direct cell killing.}, } @article {pmid28708048, year = {2017}, author = {Brilhante, RSN and Correia, EEM and Guedes, GMM and Pereira, VS and Oliveira, JS and Bandeira, SP and Alencar, LP and Andrade, ARC and Castelo-Branco, DSCM and Cordeiro, RA and Pinheiro, AQ and Chaves, LJQ and Pereira Neto, WA and Sidrim, JJC and Rocha, MFG}, title = {Quantitative and structural analyses of the in vitro and ex vivo biofilm-forming ability of dermatophytes.}, journal = {Journal of medical microbiology}, volume = {66}, number = {7}, pages = {1045-1052}, doi = {10.1099/jmm.0.000528}, pmid = {28708048}, issn = {1473-5644}, mesh = {Biofilms/*growth & development ; Humans ; Microscopy ; Microsporum/growth & development/metabolism/*physiology ; Nails/*microbiology ; Staining and Labeling ; Trichophyton/growth & development/metabolism/*physiology ; }, abstract = {PURPOSE: The aim of this study was to evaluate the in vitro and ex vivo biofilm-forming ability of dermatophytes on a nail fragment.

METHODOLOGY: Initially, four isolates of Trichophyton rubrum, six of Trichophyton tonsurans, three of Trichophyton mentagrophytes, ten of Microsporum canis and three of Microsporum gypseum were tested for production biomass by crystal violet assay. Then, one strain per species presenting the best biofilm production was chosen for further studies by optical microscopy (Congo red staining), confocal laser scanning (LIVE/DEAD staining) and scanning electron (secondary electron) microscopy.

RESULTS: Biomass quantification by crystal violet assay, optical microscope images of Congo red staining, confocal microscope and scanning electron microscope images revealed that all species studied are able to form biofilms both in vitro and ex vivo, with variable density and architecture. M. gypseum, T. rubrum and T. tonsurans produced robust biofilms, with abundant matrix and biomass, while M. canis produced the weakest biofilms compared to other species.

CONCLUSION: This study sheds light on biofilms of different dermatophyte species, which will contribute to a better understanding of the pathophysiology of dermatophytosis. Further studies of this type are necessary to investigate the processes involved in the formation and composition of dermatophyte biofilms.}, } @article {pmid28707473, year = {2017}, author = {Llama-Palacios, A and Potupa, O and Sánchez, MC and Figuero, E and Herrera, D and Sanz, M}, title = {Aggregatibacter actinomycetemcomitans Growth in Biofilm versus Planktonic State: Differential Expression of Proteins.}, journal = {Journal of proteome research}, volume = {16}, number = {9}, pages = {3158-3167}, doi = {10.1021/acs.jproteome.7b00127}, pmid = {28707473}, issn = {1535-3907}, mesh = {Adenylate Kinase/genetics/metabolism ; Aggregatibacter actinomycetemcomitans/*genetics/growth & development/isolation & purification/metabolism ; Bacterial Outer Membrane Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Dihydrolipoyllysine-Residue Acetyltransferase/genetics/metabolism ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Gene Ontology ; Humans ; Metabolic Networks and Pathways/genetics ; Molecular Chaperones/genetics/metabolism ; Molecular Sequence Annotation ; Periodontitis/microbiology ; Plankton/*genetics/growth & development/metabolism ; Two-Dimensional Difference Gel Electrophoresis ; Virulence Factors/*genetics/metabolism ; }, abstract = {Aggregatibacter actinomycetemcomitans (Aa) is a pathogenic bacterium residing in the subgingival plaque biofilm strongly associated with the pathogenesis of periodontitis. The aim of this investigation was to study the protein differential expression of Aa when growing on biofilm compared with planktonic state using proteomic analysis by the 2D-DIGE system. Eighty-seven proteins were differentially expressed during biofilm growth (1.5-fold, p < 0.05), with 13 overexpressed and 37 down-expressed. Those repressed were mainly proteins involved in metabolism, biosynthesis, and transport. The overexpressed proteins were outer membrane proteins (OMPs) and highly immunogenic proteins such as YaeT (OMP), FtsZ, OMP39, OMP18/16, the chaperone GroEL, OMPA, adenylate kinase (Adk), and dihydrolipoamide acetyltransferase. The enrichment fractions of the OMPs from biofilm and planktonic states were obtained, and these proteins were analyzed by Western blotting with human serum from a periodontitis patient and one healthy control. These immunogenic proteins overexpressed in the biofilm may represent candidate virulence factors.}, } @article {pmid28707424, year = {2017}, author = {Fernandez Y Mostajo, M and Exterkate, RAM and Buijs, MJ and Beertsen, W and van der Weijden, GA and Zaura, E and Crielaard, W}, title = {A reproducible microcosm biofilm model of subgingival microbial communities.}, journal = {Journal of periodontal research}, volume = {52}, number = {6}, pages = {1021-1031}, doi = {10.1111/jre.12473}, pmid = {28707424}, issn = {1600-0765}, mesh = {Adult ; Aged ; Biofilms/*growth & development ; Female ; Fusobacterium/growth & development ; Gingiva/*microbiology ; Humans ; Male ; *Microbiota ; Middle Aged ; Models, Biological ; Peptostreptococcus/growth & development ; Periodontal Pocket/microbiology ; Periodontitis/microbiology ; Porphyromonas/growth & development ; Veillonella/growth & development ; }, abstract = {OBJECTIVE: To develop a reproducible subgingival microcosm biofilm model.

MATERIAL AND METHODS: Subgingival plaque samples were collected from four deep pockets (probing pocket depth ≥6 mm) in each of seven patients with periodontitis and from shallow pockets (probing pocket depth ≤3 mm) in two periodontally healthy donors. An active attachment model and a peptone medium (Thompson et. al., Appl Environ Microbiol 2015;81:8307-8314) supplemented with 30% serum was used. Biofilms were harvested at 2 and 4 weeks. DNA of dead cells was blocked for amplification by propidium monoazide treatment. Composition was analyzed using 16S rRNA gene amplicon pyrosequencing. Similarities between the biofilm samples were assessed by non-metric multidimensional scaling using the Bray-Curtis similarity index and similarity percentage analysis. Data from duplicate experiments, different biofilm sources and different biofilm age were compared.

RESULTS: The non-metric multidimensional scaling revealed a strong clustering by the inoculum source, the donor and their periodontal status. Statistically significant differences were found between the sources of inoculum (P=.0001) and biofilm age (P=.0016). Furthermore, periodontitis biofilms (P) were distinct in composition from health-derived biofilms (H) by genera: Porphyromonas (P=19%; H=0%), Filifactor (P=10%; H=0%), Anaeroglobus (P=3%; H=0%), Phocaeicola (P=1.5%; H=0%), Parvimonas (P=19%; H=14%), Fusobacterium (P=2%; H=26%), Peptostreptococcus (P=20%; H=30%), Veillonella (P=7%; H=8%) and 57 other genera. Similarity distances (Bray-Curtis) (mean 0.73, SD 0.15) and the Shannon diversity index (mean 2, SD 0.2) revealed no differences between duplicate experiments (P=.121).

CONCLUSION: This biofilm model allows reproducible production of complex subgingival microbial communities.}, } @article {pmid28707417, year = {2017}, author = {Chaton, CT and Herr, AB}, title = {Defining the metal specificity of a multifunctional biofilm adhesion protein.}, journal = {Protein science : a publication of the Protein Society}, volume = {26}, number = {10}, pages = {1964-1973}, pmid = {28707417}, issn = {1469-896X}, support = {R01 GM094363/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Bacterial Proteins/*chemistry/genetics/*metabolism ; Biofilms ; Cloning, Molecular ; Escherichia coli/genetics ; Metals, Heavy/*chemistry/*metabolism ; Models, Molecular ; Recombinant Proteins/chemistry/genetics/metabolism ; Staphylococcus epidermidis/chemistry/genetics ; Ultracentrifugation ; }, abstract = {The accumulation associated protein (Aap) of Staphylococcus epidermidis mediates intercellular adhesion events necessary for biofilm growth. This process depends upon Zn[2+] -induced self-assembly of G5 domains within the B-repeat region of the protein, forming anti-parallel, intertwined protein "ropes" between cells. Pleomorphism in the Zn[2+] -coordinating residues was observed in previously solved crystal structures, suggesting that the metal binding site might accommodate other transition metals and thereby support dimerization. By use of carefully selected buffer systems and a specialized approach to analyze sedimentation velocity analytical ultracentrifugation data, we were able to analyze low-affinity metal binding events in solution. Our data show that both Zn[2+] and Cu[2+] support B-repeat assembly, whereas Mn[2+] , Co[2+] , and Ni[2+] bind to Aap but do not support self-association. As the number of G5 domains are increased in longer B-repeat constructs, the total concentration of metal required for dimerization decreases and the transition between monomer and dimer becomes more abrupt. These characteristics allow Aap to function as an environmental sensor that regulates biofilm formation in response to local concentrations of Zn[2+] and Cu[2+] , both of which are implicated in immune cell activity.}, } @article {pmid28707067, year = {2017}, author = {Zhao, Y and Song, F and Wang, H and Zhou, J and Ren, D}, title = {Phagocytosis of Escherichia coli biofilm cells with different aspect ratios: a role of substratum material stiffness.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {16}, pages = {6473-6481}, pmid = {28707067}, issn = {1432-0614}, support = {R21 EY025750/EY/NEI NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion ; Biofilms/drug effects/*growth & development ; Dimethylpolysiloxanes/chemistry ; Escherichia coli/drug effects/*physiology ; Humans ; Macrophages/microbiology ; Microbial Viability ; *Phagocytosis ; Surface Properties ; U937 Cells ; }, abstract = {Bacterial biofilms play an important role in chronic infections due to high-level tolerance to antibiotics. Thus, it is important to eradicate bacterial cells that are attached to implanted medical devices of different materials. Phagocytosis is a key process of the innate immunity to eliminate invading pathogens. Previous research demonstrated that the efficiency of phagocytosis is affected by the aspect ratio of polymer beads. Recently, we reported that the stiffness of polydimethylsiloxane (PDMS) influences Escherichia coli biofilm formation and the biofilm cells on stiff (5:1) PDMS are 46.2% shorter than those on soft (40:1) PDMS. Based on these findings, we hypothesized that E. coli cells attached on stiff PDMS can be more effectively removed via phagocytosis. This hypothesis was tested in the present study using viability assays, flow cytometry, and cell tracking. The results revealed that shorter E. coli cells detached from stiff PDMS were easier to be phagocytized than the longer cells from soft PDMS surfaces. Furthermore, macrophage cells were found to be more motile on stiff PDMS surfaces and more effective at phagocytosis of E. coli cells attached on these surfaces. These results may help the design of better biomaterials to reduce fouling and associated infections.}, } @article {pmid28706760, year = {2017}, author = {Ashok, R and Ganesh, A and Deivanayagam, K}, title = {Bactericidal Effect of Different Anti-Microbial Agents on Fusobacterium Nucleatum Biofilm.}, journal = {Cureus}, volume = {9}, number = {6}, pages = {e1335}, pmid = {28706760}, issn = {2168-8184}, abstract = {INTRODUCTION: The root canal anatomy of the teeth is very complex. Complete debridement of the root canals is a challenge and is very important for the success of the root canal treatment. Hence, this study was done to find an effective irrigant which can be used during root canal treatment.

OBJECTIVE: The bactericidal effect of a potential root canal irrigant was compared with two commonly used root canal irrigants against monoculture biofilm of a commercially available isolate of Fusobacterium nucleatum.

METHODS: A monoculture biofilm of Fusobacterium nucleatum was grown on glass slides. The glass slides containing the biofilm were immersed in centrifuge tubes containing 5% sodium hypochlorite, 2% Chlorhexidine, 6% turmeric solution, 9% turmeric solution and distilled water for a time span of one minute. A wire loop was used to scrape off the biofilms onto sterile brain heart infusion agar plates. This was further subjected to an incubation period of 96 hours at 37° C. Colony forming units were quantified by statistical analysis and results were obtained.

RESULTS: The anti-bacterial activity of 6% and 9% turmeric solution was statistically significant against Fusobacterium nucleatum when compared to 2% Chlorhexidine and 5% sodium hypochlorite.

CONCLUSION: In endodontic treatment, turmeric solution may be considered as an effective irrigant.}, } @article {pmid28705748, year = {2017}, author = {Tiwari, V and Tiwari, D and Patel, V and Tiwari, M}, title = {Effect of secondary metabolite of Actinidia deliciosa on the biofilm and extra-cellular matrix components of Acinetobacter baumannii.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {345-351}, doi = {10.1016/j.micpath.2017.07.013}, pmid = {28705748}, issn = {1096-1208}, mesh = {Acinetobacter Infections/drug therapy/microbiology ; Acinetobacter baumannii/*drug effects/growth & development ; Actinidia/*chemistry ; Alkaloids/isolation & purification/pharmacology ; Amyloidogenic Proteins/drug effects ; Anti-Bacterial Agents/chemistry/*pharmacology/therapeutic use ; Bacterial Proteins/drug effects ; Biofilms/*drug effects/growth & development ; Carbapenems/pharmacology ; Colony Count, Microbial ; DNA, Bacterial/drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Flavonoids/pharmacology ; Microbial Sensitivity Tests ; Phytochemicals/chemistry/pharmacology ; Plant Extracts/chemistry/*pharmacology/therapeutic use ; Polysaccharides, Bacterial/metabolism ; *Secondary Metabolism ; Syzygium/chemistry ; }, abstract = {Acinetobacter baumannii, opportunistic nosocomial pathogen, increases gradually in the clinical setup. The high level of resistance mechanisms acquired by these bacteria makes their eradication difficult and biofilm formation is one of them. Biofilm comprises of closely packed bacterial population crowded together by extra-cellular matrix (ECM). ECM contains bacterial secreted polymers such as exopolysaccharides (EPS), proteins and extracellular-DNA (e-DNA) and rarely amyloidogenic proteins. Biofilm offers protection of underlying bacterial population against chemotherapeutic agents and host immune system. Therefore, present efforts are focused to find a novel therapeutic that targets biofilm-associated infections. Plants are used as a natural therapeutic for numerous ailments. In order to find an alternative of the available antibacterial drugs, we have focused on the natural herbal active compounds. In this study, we have extracted active compounds from various medicinal plants and screened its anti-biofilm activity against carbapenem resistant strain of A. baumannii. Results showed that polar extract of kiwi (Actinidia deliciosa) and clove (Syzygium aromaticum) exhibit effective anti-biofilm activity. These two plants were also used for their phytochemical screening and TLC profiling to find out the constituting secondary metabolites. Actinidia deliciosa extract contains an alkaloid (sanquinarine) as well as a flavonoid (hydroxyflavone). Anti-biofilm effect of this extract on the ECM of A. baumannii showed that it reduces EPS, protein and eDNA contents in the ECM. Proteins of ECM have also shown to form amyloid like structure, which was evident from its interaction with the Congo Red. CFU counting after Actinidia deliciosa extract treatment also supported the results. Therefore, it can be concluded that polar extract of A. deliciosa can be used to find suitable alternative therapeutic to control biofilm formation by carbapenem resistant strain of Acinetobacter baumannii.}, } @article {pmid28705677, year = {2018}, author = {Duarte, AFS and Ceotto-Vigoder, H and Barrias, ES and Souto-Padrón, TCBS and Nes, IF and Bastos, MDCF}, title = {Hyicin 4244, the first sactibiotic described in staphylococci, exhibits an anti-staphylococcal biofilm activity.}, journal = {International journal of antimicrobial agents}, volume = {51}, number = {3}, pages = {349-356}, doi = {10.1016/j.ijantimicag.2017.06.025}, pmid = {28705677}, issn = {1872-7913}, mesh = {Animals ; Anti-Infective Agents/*isolation & purification/*pharmacology ; Bacteriocins/*isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biosynthetic Pathways/genetics ; Cattle ; Colony Count, Microbial ; Gene Expression Profiling ; Humans ; Mastitis, Bovine/microbiology ; Microbial Viability/drug effects ; Multigene Family ; Sequence Homology ; Staphylococcal Infections/microbiology/veterinary ; Staphylococcus/drug effects/isolation & purification/*metabolism ; }, abstract = {Hyicin 4244 is a small antimicrobial peptide with a broad spectrum of activity that was found in the culture supernatant of Staphylococcus hyicus 4244, the genome of which was then sequenced. The bacteriocin gene cluster (hyiSABCDEFG) was mined from its single chromosome and exhibited a genetic organization similar to that of subtilosin A. All genes involved in hyicin 4244 biosynthesis proved to be transcribed and encode proteins that share at least 42% similarity to proteins encoded by the subtilosin A gene cluster. Due to its resemblance to subtilosin A and the presence of three thioether bonds in its structure, hyicin 4244 is assumed to be a 35-amino acid circular sactibiotic, the first to be described in staphylococci. Hyicin 4244 inhibited 14 staphylococcal isolates from either human infections or bovine mastitis, all biofilm formers. Hyicin 4244 significantly reduced the number of colony-forming units (CFU) and the biofilm formation by two strong biofilm-forming strains randomly chosen as representatives of the strains involved in human infections and bovine mastitis. It also reduced the proliferation and viability of sessile cells in established biofilms. Therefore, hyicin 4244 proved not only to prevent biofilm formation by planktonic cells, but also to penetrate the biofilm matrix in vitro, exerting bactericidal activity against staphylococcal sessile cells. This bacteriocin has the potential to become an alternative antimicrobial for either prevention or treatment of biofilm-related infections caused by different staphylococcal species.}, } @article {pmid28705197, year = {2017}, author = {Zhou, Y and Yu, L and Tao, Y and Zhi, Q and Lin, H}, title = {Genetic polymorphism of scrA gene of Streptococcus mutans isolates is not associated with biofilm formation in severe early childhood caries.}, journal = {BMC oral health}, volume = {17}, number = {1}, pages = {114}, pmid = {28705197}, issn = {1472-6831}, mesh = {*Biofilms/growth & development ; Case-Control Studies ; Child, Preschool ; DNA, Bacterial/genetics ; Dental Caries/*microbiology ; Genes, Bacterial/*genetics ; Humans ; Mutation, Missense/genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic/genetics ; Silent Mutation/genetics ; Streptococcus mutans/*genetics/isolation & purification ; }, abstract = {BACKGROUND: To explore and analyse the association between biofilm and the genetic polymorphisms of scrA gene of EnzymeIIscr found in clinical isolates of Streptococcus mutans (S. mutans) from severe early childhood caries (S-ECC) in 3 years old children.

METHODS: Clinical strains of S. mutans were conserved from a previous study. Thirty strains of S. mutans from the S-ECC group and 30 strains of S. mutans from the caries free (CF) group were selected. Biomass and viability of biofilm formed by the strains were evaluated by crystal violet and alamar blue assay. Genomic DNA was extracted from the S. mutans isolates. PCR was conducted to amplify scrA gene. After purified and sequenced the PCR products, BioEdit sofeware was used to analyse the sequence results. A chi-square test was used to compare the results.

RESULTS: Compared to the CF group, the biomass of S-ECC group was higher (P = 0.0424). However, the viability of the two groups showed no significant difference. All 60 clinically isolated S. mutans strains had a 1995 base pair (bp) scrA gene. Forty-nine point mutations were identified in scrA from the 60 clinical isolates. There were 17 missense point mutations at the 10, 65, 103, 284, 289, 925, 1444, 1487, 1494, 1508, 1553, 1576, 1786, 1822, 1863, 1886, and 1925 bp positions. The other 32 mutations were silent point mutations. No positions were found at active sites of ScrA. The statistic analyse showed no significant missense mutation rates between the two groups.

CONCLUSIONS: There was no association between biofilm and genetic polymorphisms of scrA from S. mutans with S-ECC in 3 years old children.}, } @article {pmid28704738, year = {2017}, author = {Song, TS and Zhang, H and Liu, H and Zhang, D and Wang, H and Yang, Y and Yuan, H and Xie, J}, title = {High efficiency microbial electrosynthesis of acetate from carbon dioxide by a self-assembled electroactive biofilm.}, journal = {Bioresource technology}, volume = {243}, number = {}, pages = {573-582}, doi = {10.1016/j.biortech.2017.06.164}, pmid = {28704738}, issn = {1873-2976}, mesh = {Acetates ; *Biofilms ; Carbon Dioxide ; Electrodes ; Oxides ; }, abstract = {Microbial electrosynthesis (MES) is a biocathode-driven process, producing high-value chemicals from CO2. Here, an in situ self-assembled graphene oxide (rGO)/biofilm was constructed, in MES, for high efficient acetate production. GO has been successfully reduced by electroautotrophic bacteria for the first time. An increase, of 1.5 times, in the volumetric acetate production rate, was obtained by self-assembling rGO/biofilm, as compared to the control group. In MES with rGO/biofilm, a volumetric acetate production rate of 0.17gl[-1]d[-1] has been achieved, 77% of the electrons consumed, were recovered and the final acetate concentration reached 7.1gl[-1], within 40days. A three-dimensional rGO/biofilm was constructed enabling highly efficient electron transfer rates within biofilms, and between biofilm and electrode, demonstrating that the development of 3D electroactive biofilms, with higher extracellular electron transfer rates, is an effective approach to improving MES efficiency.}, } @article {pmid28704490, year = {2017}, author = {Paulone, S and Ardizzoni, A and Tavanti, A and Piccinelli, S and Rizzato, C and Lupetti, A and Colombari, B and Pericolini, E and Polonelli, L and Magliani, W and Conti, S and Posteraro, B and Cermelli, C and Blasi, E and Peppoloni, S}, title = {The synthetic killer peptide KP impairs Candida albicans biofilm in vitro.}, journal = {PloS one}, volume = {12}, number = {7}, pages = {e0181278}, pmid = {28704490}, issn = {1932-6203}, mesh = {Antifungal Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Cell Membrane/drug effects/metabolism ; Fluconazole/pharmacology ; Microbial Sensitivity Tests ; Oxidative Stress/drug effects ; Peptides/chemical synthesis/*pharmacology ; Permeability/drug effects ; Proteoglycans ; Single-Chain Antibodies/chemistry/*pharmacology ; beta-Glucans/chemistry/immunology ; }, abstract = {Candida albicans is a commensal organism, commonly inhabiting mucosal surfaces of healthy individuals, as a part of the resident microbiota. However, in susceptible hosts, especially hospitalized and/or immunocompromised patients, it may cause a wide range of infections. The presence of abiotic substrates, such as central venous or urinary catheters, provides an additional niche for Candida attachment and persistence, particularly via biofilm development. Furthermore, Candida biofilm is poorly susceptible to most antifungals, including azoles. Here we investigated the effects of a synthetic killer peptide (KP), known to be active in vitro, ex vivo and/or in vivo against different pathogens, on C. albicans biofilm. Together with a scrambled peptide used as a negative control, KP was tested against Candida biofilm at different stages of development. A reference strain, two fluconazole-resistant and two fluconazole-susceptible C. albicans clinical isolates were used. KP-induced C. albicans oxidative stress response and membrane permeability were also analysed. Moreover, the effect of KP on transcriptional profiles of C. albicans genes involved in different stages of biofilm development, such as cell adhesion, hyphal development and extracellular matrix production, was evaluated. Our results clearly show that the treatment with KP strongly affected the capacity of C. albicans to form biofilm and significantly impairs preformed mature biofilm. KP treatment resulted in an increase in C. albicans oxidative stress response and membrane permeability; also, biofilm-related genes expression was significantly reduced. Comparable inhibitory effects were observed in all the strains employed, irrespective of their resistance or susceptibility to fluconazole. Finally, KP-mediated inhibitory effects were observed also against a catheter-associated C. albicans biofilm. This study provides the first evidence on the KP effectiveness against C. albicans biofilm, suggesting that KP may be considered as a potential novel tool for treatment and prevention of biofilm-related C. albicans infections.}, } @article {pmid28704171, year = {2017}, author = {Agostinho Hunt, AM and Gibson, JA and Larrivee, CL and O'Reilly, S and Navitskaya, S and Needle, DB and Abramovitch, RB and Busik, JV and Waters, CM}, title = {A bioluminescent Pseudomonas aeruginosa wound model reveals increased mortality of type 1 diabetic mice to biofilm infection.}, journal = {Journal of wound care}, volume = {26}, number = {Sup7}, pages = {S24-S33}, doi = {10.12968/jowc.2017.26.Sup7.S24}, pmid = {28704171}, issn = {0969-0700}, mesh = {Animals ; *Biofilms ; Diabetes Mellitus, Experimental/*physiopathology ; Diabetes Mellitus, Type 1/*physiopathology ; Male ; Mice ; Microorganisms, Genetically-Modified ; Pseudomonas Infections/mortality/*pathology/physiopathology ; Pseudomonas aeruginosa/genetics ; *Wound Healing ; Wound Infection/mortality/*pathology/physiopathology ; }, abstract = {OBJECTIVE: To examine how bacterial biofilms, as contributing factors in the delayed closure of chronic wounds in patients with diabetes, affect the healing process.

METHOD: We used daily microscopic imaging and the IVIS Spectrum in vivo imaging system to monitor biofilm infections of bioluminescent Pseudomonas aeruginosa and evaluate healing in non-diabetic and streptozotocin-induced diabetic mice.

RESULTS: Our studies determined that diabetes alone did not affect the rate of healing of full-depth murine back wounds compared with non-diabetic mice. The application of mature biofilms to the wounds significantly decreased the rate of healing compared with non-infected wounds for both non-diabetic as well as diabetic mice. Diabetic mice were also more severely affected by biofilms displaying elevated pus production, higher mortality rates and statistically significant increase in wound depth, granulation/fibrosis and biofilm presence. Introduction of a mutant Pseudomonas aeruginosa capable of producing high concentrations of cyclic di-GMP did not result in increased persistence in either diabetic or non-diabetic animals compared with the wild type strain.

CONCLUSION: Understanding the interplay between diabetes and biofilms may lead to novel treatments and better clinical management of chronic wounds.}, } @article {pmid28703765, year = {2017}, author = {Norcy, TL and Niemann, H and Proksch, P and Linossier, I and Vallée-Réhel, K and Hellio, C and Faÿ, F}, title = {Anti-Biofilm Effect of Biodegradable Coatings Based on Hemibastadin Derivative in Marine Environment.}, journal = {International journal of molecular sciences}, volume = {18}, number = {7}, pages = {}, pmid = {28703765}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/growth & development ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Biofouling ; Cell Count ; Coated Materials, Biocompatible/*pharmacology ; *Ecosystem ; Microalgae/drug effects ; Paint ; Plankton/cytology/drug effects ; }, abstract = {Dibromohemibastadin-1 (DBHB) is an already known potent inhibitor of blue mussel phenoloxidase (which is a key enzyme involved in bioadhesion). Within this study, the potentiality of DBHB against microfouling has been investigated. The activity of DBHB was evaluated on key strains of bacteria and microalgae involved in marine biofilm formation and bioassays assessing impact on growth, adhesion and biofilm formation were used. To assess the efficiency of DBHB when included in a matrix, DBHB varnish was prepared and the anti-microfouling activity of coatings was assessed. Both in vitro and in situ immersions were carried out. Confocal Laser Scanning Microscopy (CLSM) was principally used to determine the biovolume and average thickness of biofilms developed on the coatings. Results showed an evident efficiency of DBHB as compound and varnish to reduce the biofilm development. The mode of action seems to be based principally on a perturbation of biofilm formation rather than on a biocidal activity in the tested conditions.}, } @article {pmid28703700, year = {2017}, author = {Bardoloi, V and Yogeesha Babu, KV}, title = {Comparative study of isolates from community-acquired and catheter-associated urinary tract infections with reference to biofilm-producing property, antibiotic sensitivity and multi-drug resistance.}, journal = {Journal of medical microbiology}, volume = {66}, number = {7}, pages = {927-936}, doi = {10.1099/jmm.0.000525}, pmid = {28703700}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects/*growth & development/isolation & purification ; Biofilms/*growth & development ; Catheter-Related Infections/*microbiology ; Community-Acquired Infections/*microbiology ; Disk Diffusion Antimicrobial Tests ; *Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Male ; Prospective Studies ; Urinary Tract Infections/*microbiology ; }, abstract = {PURPOSE: Urinary tract infection (UTI) can be community-acquired (Com-UTI) or catheter-associated (CAUTI) and may be associated with biofilm-producing organisms. A comparative analysis of biofilm-producing property (BPP), antibiotic-sensitivity and multi-drug resistance (MDR) and their relation with the BPP of isolates from Com-UTI and CAUTI has not yet been performed and necessitated this study.

OBJECTIVES: (1) isolation of bacteria from CAUTI and Com-UTI and identification of their BPP, antibiotic-sensitivity and MDR status; (2) comparison of the isolates from CAUTI and Com-UTI as regards BPP, MDR status and their relation with BPP.

METHOD: isolates from 100 cases each of Com-UTI and CAUTI were subjected to Congo redagar (CRA) and Safranin tube tests. Antibiotic susceptibility was investigated using the disc diffusion method. Both groups were compared regarding BPP, drug sensitivity and MDR status. Statistical analyses were performed using χ2 and Fisher's exact tests.

RESULTS: 76.19 % of isolates from Com-UTI and 60.72 % from CAUTI had BPP (P=0.0252; significant). The Safranin tube test detected more isolates with BPP than the CRA test. MDR is greater in CAUTI than Com-UTI (83.33 % versus 64.76 %; P=0.0039; significant). MDR is greater in isolates with BPP in both Com-UTI and CAUTI (76.47 and 62.35 %; non-significant).

CONCLUSIONS: BPP was found in both Com-UTI and CAUTI. When used together, the Safranin tube test and the CRA test increased the sensitivity of detecting BPP. MDR was higher in CAUTI than Com-UTI. MDR and BPP are not interrelated or associated, especially in settings where it is not certain that isolates were obtained from a well-formed biofilm. However, this does not rule out a higher incidence or prevalence of MDR in isolates with BPP taken directly from the biofilms.}, } @article {pmid28702905, year = {2017}, author = {Ramírez-Aldaba, H and Vazquez-Arenas, J and Sosa-Rodríguez, FS and Valdez-Pérez, D and Ruiz-Baca, E and García-Meza, JV and Trejo-Córdova, G and Lara, RH}, title = {Assessment of biofilm changes and concentration-depth profiles during arsenopyrite oxidation by Acidithiobacillus thiooxidans.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {24}, pages = {20082-20092}, pmid = {28702905}, issn = {1614-7499}, mesh = {Acidithiobacillus thiooxidans/*drug effects/growth & development ; Arsenicals/*metabolism ; Biodegradation, Environmental ; Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Iron Compounds/*metabolism/toxicity ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Minerals/*metabolism/toxicity ; Oxidation-Reduction ; Spectrum Analysis, Raman ; Sulfides/*metabolism/toxicity ; Water Pollutants, Chemical/*metabolism/toxicity ; }, abstract = {Biofilm formation and evolution are key factors to consider to better understand the kinetics of arsenopyrite biooxidation. Chemical and surface analyses were carried out using Raman spectroscopy, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS), and protein analysis (i.e., quantification) in order to evaluate the formation of intermediate secondary compounds and any significant changes arising in the biofilm structure of Acidithiobacillus thiooxidans during a 120-h period of biooxidation. Results show that the biofilm first evolves from a low cell density structure (1 to 12 h) into a formation of microcolonies (24 to 120 h) and then finally becomes enclosed by a secondary compound matrix that includes pyrite (FeS2)-like, S n[2-]/S[0], and As2S3 compounds, as shown by Raman and SEM-EDS. GDS analyses (concentration-depth profiles, i.e., 12 h) indicate significant differences for depth speciation between abiotic control and biooxidized surfaces, thus providing a quantitative assessment of surface-bulk changes across samples (i.e. reactivity and /or structure-activity relationship). Respectively, quantitative protein analyses and CLSM analyses suggest variations in the type of extracellular protein expressed and changes in the biofilm structure from hydrophilic (i.e., exopolysaccharides) to hydrophobic (i.e., lipids) due to arsenopyrite and cell interactions during the 120-h period of biooxidation. We suggest feasible environmental and industrial implications for arsenopyrite biooxidation based on the findings of this study.}, } @article {pmid28702588, year = {2017}, author = {Ghosh, C and Sarkar, P and Samaddar, S and Uppu, DSSM and Haldar, J}, title = {l-Lysine based lipidated biphenyls as agents with anti-biofilm and anti-inflammatory properties that also inhibit intracellular bacteria.}, journal = {Chemical communications (Cambridge, England)}, volume = {53}, number = {60}, pages = {8427-8430}, doi = {10.1039/c7cc04206j}, pmid = {28702588}, issn = {1364-548X}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Biphenyl Compounds/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Lipids/chemistry/*pharmacology ; Lysine/chemistry/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Molecular Structure ; }, abstract = {l-Lysines were conjugated to lipidated biphenyls using simple synthetic chemistry to obtain selective membrane-active antibacterial agents that inhibit cell-wall biosynthesis. The most selective compound bore promising activity against biofilm-related infections and intracellular bacteria, and also suppressed the stimulation of TNF-α induced by lipoteichoic acid. Belligerent to resistance development, it was active in a murine model of MRSA infection.}, } @article {pmid28702016, year = {2017}, author = {Yin, S and Jiang, B and Huang, G and Gong, Y and You, B and Yang, Z and Chen, Y and Chen, J and Yuan, Z and Li, M and Hu, F and Zhao, Y and Peng, Y}, title = {Burn Serum Increases Staphylococcus aureus Biofilm Formation via Oxidative Stress.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1191}, pmid = {28702016}, issn = {1664-302X}, abstract = {Staphylococcus aureus is a common pathogen isolated from burn patients that can form biofilms on burn wounds and implanted deep vein catheters, which often leads to refractory infections or even biofilm-related sepsis. As biofilm formation is usually regulated by environmental conditions, we hypothesized that serum composition may be altered after burn injury, potentially affecting the ability of infecting bacteria to form biofilms. As predicted, we observed that serum from burn-injured rats increases biofilm formation by S. aureus and also induces bacterial aggregation and adherence to human fibronectin and fibrinogen. Analysis of potential regulatory factors revealed that exposure to burn serum decreases expression of the quorum-sensing agr system and increases mRNA levels of some biofilm inducers such as sarA and icaA. In addition, we also observed that burn serum imposes oxidative stress and increases expression of key oxidoreductase genes (sodA, sodM, katA, and ahpC) in S. aureus. Importantly, the ability of burn serum to enhance biofilm formation and bacterial cell aggregation can be abrogated by treatment with an antioxidant. Taken together, these findings indicate that burn serum increases S. aureus biofilm formation via elevated oxidative stress, and may lead to novel strategies to control biofilm formation and infection in burn patients.}, } @article {pmid28701712, year = {2017}, author = {van Duuren, JBJH and Müsken, M and Karge, B and Tomasch, J and Wittmann, C and Häussler, S and Brönstrup, M}, title = {Use of Single-Frequency Impedance Spectroscopy to Characterize the Growth Dynamics of Biofilm Formation in Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5223}, pmid = {28701712}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Dielectric Spectroscopy/*methods ; Microbial Sensitivity Tests ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/genetics/*growth & development ; }, abstract = {Impedance spectroscopy has been applied in prokaryotic and eukaryotic cytometry as a label-free method for the investigation of adherent cells. In this paper, its use for characterizing the growth dynamics of P. aeruginosa biofilms is described and compared to crystal violet staining and confocal microscopy. The method allows monitoring the growth of biofilm-forming P. aeruginosa in a continuous and label-free manner over a period of 72 h in a 96 well plate format. Impedance curves obtained for P. aeruginosa PA14 wild type and mutant strains with a transposon insertion in pqsA and pelA genes exhibited distinct phases. We propose that the slope of the declining curve following a maximum at ca. 35-40 h is a measure of biofilm formation. Transplant experiments with P. aeruginosa biofilms and paraffin suggest that the impedance also reflects pellicle formation at the liquid-air interface, a barely considered contributor to impedance. Finally, the impairment of biofilm formation upon treatment of cultures with L-arginine and with ciprofloxacin, tobramycin and meropenem was studied by single frequency impedance spectroscopy. We suggest that these findings qualify impedance spectroscopy as an additional technique to characterize biofilm formation and its modulation by small molecule drugs.}, } @article {pmid28701036, year = {2017}, author = {Liu, W and Li, S and Wang, Z and Yan, ECY and Leblanc, RM}, title = {Characterization of Surface-Active Biofilm Protein BslA in Self-Assembling Langmuir Monolayer at the Air-Water Interface.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {33}, number = {30}, pages = {7548-7555}, doi = {10.1021/acs.langmuir.7b01739}, pmid = {28701036}, issn = {1520-5827}, mesh = {Air ; Bacillus subtilis ; *Biofilms ; Membrane Proteins ; Spectrophotometry, Infrared ; Surface Properties ; Water ; }, abstract = {Biofilm is an extracellular matrix of bacteria and serves as a protective shield of bacterial communities. It is crucial for microbial growth and one of the leading causes of human chronic infections as well. However, the structures and molecular mechanism of biofilm formation remain largely unknown. Here, we examined a protein, BslA, expressed in the biofilms of Bacillus subtilis. We characterized the Langmuir monolayers of BslA at the air/water interface. Using techniques in surface chemistry and spectroscopy, we found that BslA forms a stable and robust Langmuir monolayer at the air/water interface. Our results show that the BslA Langmuir monolayer underwent two-stage elasticity in the solid state phase upon mechanical compression: one is possibly due to the intermolecular interaction and the other is likely due to both the intermolecular compulsion and the intramolecular distortion. The Langmuir monolayer of BslA shows abrupt changes in rigidities and elasticities at ∼25 mN/m. This surface pressure is close to the one at which BlsA saturates the air/water interface as a self-assembled film without mechanical compression, corresponding to a mean molecular area of ∼700 Å[2] per molecule. Based on the results of surface UV-visible spectroscopy and infrared reflective-absorption spectroscopy, we propose that the BslA Langmuir monolayer carries intermolecular elasticity before ∼25 mN/m and both intermolecular and intramolecular elasticity after ∼25 mN/m. These results provide valuable insights into the understanding of biofilm-associated protein under high mechanical force, shedding light on further investigation of biofilm structure and functionalities.}, } @article {pmid28700262, year = {2017}, author = {Jakubovics, NS}, title = {The sixth sensor: A Candida albicans biofilm master regulator that responds to inter-kingdom interactions.}, journal = {Virulence}, volume = {8}, number = {8}, pages = {1465-1467}, pmid = {28700262}, issn = {2150-5608}, mesh = {*Biofilms ; *Candida albicans ; Fungal Proteins ; Transcription Factors ; }, } @article {pmid28700050, year = {2017}, author = {Soroush, S and Jabalameli, F and Taherikalani, M and Eslampour, MA and Beigverdi, R and Emaneini, M}, title = {Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {50}, number = {3}, pages = {329-333}, doi = {10.1590/0037-8682-0384-2016}, pmid = {28700050}, issn = {1678-9849}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Child ; Chromosomes, Bacterial/*genetics ; DNA, Bacterial ; Drug Resistance, Bacterial ; Humans ; Iran ; Methicillin Resistance/*genetics ; Microbial Sensitivity Tests ; Staphylococcal Infections/*microbiology ; Staphylococcus hominis/*drug effects/physiology ; }, abstract = {INTRODUCTION:: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients.

METHODS:: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay.

RESULTS:: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II.

CONCLUSIONS:: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.}, } @article {pmid28699879, year = {2017}, author = {Dawe, H and Berger, E and Sihlbom, C and Angus, EM and Howlin, RP and Laver, JR and Tebruegge, M and Hall-Stoodley, L and Stoodley, P and Faust, SN and Allan, RN}, title = {D-methionine interferes with non-typeable Haemophilus influenzae peptidoglycan synthesis during growth and biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {7}, pages = {1093-1104}, doi = {10.1099/mic.0.000491}, pmid = {28699879}, issn = {1465-2080}, support = {//Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Haemophilus Infections/*microbiology ; Haemophilus influenzae/drug effects/genetics/*growth & development/*metabolism ; Humans ; Methionine/*metabolism ; Peptidoglycan/*biosynthesis ; }, abstract = {Non-typeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that plays a major role in a number of respiratory tract infections, including otitis media, cystic fibrosis and chronic obstructive pulmonary disease. Biofilm formation has been implicated in both NTHi colonization and disease, and is responsible for the increased tolerance of this pathogen towards antibiotic treatment. Targeting metabolic pathways that are important in NTHi biofilm formation represents a potential strategy to combat this antibiotic recalcitrance. A previous investigation demonstrated increased expression of a putative d-methionine uptake protein following exposure of NTHi biofilms to the ubiquitous signalling molecule, nitric oxide. We therefore hypothesized that treatment with exogenous d-methionine would impact on NTHi biofilm formation and increase antibiotic sensitivity. Treatment of NTHi during the process of biofilm formation resulted in a reduction in biofilm viability, increased biomass, changes in the overall biofilm architecture and the adoption of an amorphous cellular morphology. Quantitative proteomic analyses identified 124 proteins that were differentially expressed following d-methionine treatment, of which 51 (41 %) were involved in metabolic and transport processes. Nine proteins involved in peptidoglycan synthesis and cell division showed significantly increased expression. Furthermore, d-methionine treatment augmented the efficacy of azithromycin treatment and highlighted the potential of d-methionine as an adjunctive therapeutic approach for NTHi biofilm-associated infections.}, } @article {pmid28698374, year = {2017}, author = {Arnaouteli, S and Ferreira, AS and Schor, M and Morris, RJ and Bromley, KM and Jo, J and Cortez, KL and Sukhodub, T and Prescott, AR and Dietrich, LEP and MacPhee, CE and Stanley-Wall, NR}, title = {Bifunctionality of a biofilm matrix protein controlled by redox state.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {30}, pages = {E6184-E6191}, pmid = {28698374}, issn = {1091-6490}, support = {R01 AI103369/AI/NIAID NIH HHS/United States ; BB/P001335/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 097945/B/11/Z/WT_/Wellcome Trust/United Kingdom ; T32 GM008798/GM/NIGMS NIH HHS/United States ; BB/L006979/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N022254/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M013774/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L006804/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/genetics/*physiology ; Bacterial Proteins/chemistry/metabolism/*physiology ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Oxidation-Reduction ; }, abstract = {Biofilms are communities of microbial cells that are encapsulated within a self-produced polymeric matrix. The matrix is critical to the success of biofilms in diverse habitats; however, many details of the composition, structure, and function remain enigmatic. Biofilms formed by the Gram-positive bacterium Bacillus subtilis depend on the production of the secreted film-forming protein BslA. Here, we show that a gradient of electron acceptor availability through the depth of the biofilm gives rise to two distinct functional roles for BslA and that these roles can be genetically separated through targeted amino acid substitutions. We establish that monomeric BslA is necessary and sufficient to give rise to complex biofilm architecture, whereas dimerization of BslA is required to render the community hydrophobic. Dimerization of BslA, mediated by disulfide bond formation, depends on two conserved cysteine residues located in the C-terminal region. Our findings demonstrate that bacteria have evolved multiple uses for limited elements in the matrix, allowing for alternative responses in a complex, changing environment.}, } @article {pmid28697551, year = {2017}, author = {Sheng, H and Harir, M and Boughner, LA and Jiang, X and Schmitt-Kopplin, P and Schroll, R and Wang, F}, title = {N-acyl-homoserine lactone dynamics during biofilm formation of a 1,2,4-trichlorobenzene mineralizing community on clay.}, journal = {The Science of the total environment}, volume = {605-606}, number = {}, pages = {1031-1038}, doi = {10.1016/j.scitotenv.2017.06.233}, pmid = {28697551}, issn = {1879-1026}, mesh = {Acyl-Butyrolactones/*chemistry ; *Aluminum Silicates ; *Biofilms ; Chlorobenzenes/*metabolism ; Clay ; Gram-Negative Bacteria/*metabolism ; In Situ Hybridization, Fluorescence ; Quorum Sensing ; }, abstract = {In Gram-negative bacteria, quorum sensing systems are based on the N-acyl-homoserine lactone (AHL) molecule. The objective of this study was to investigate the role of quorum sensing systems during biofilm formation by a microbial community while degrading the pollutant. Our model system included 1,2,4-trichlorobenzene (1,2,4-TCB) and its mineralizing Gram-negative bacterial community to investigate the relationships between AHL dynamics, cell growth and pollutant degradation. Biomineralization of 1,2,4-TCB was monitored for both the planktonic bacterial community with and without sterile clay particles in liquid cultures. The bacterial growth and production of AHLs were quantified by fluorescent in situ hybridization and immunoassay analysis, respectively. A rapid production of AHLs which occurred coincided with the biofilm formation and the increase of mineralization rate of 1,2,4-TCB in liquid cultures. There is a positive correlation between the cell density of Bodertella on the clay particles and mineralization rate of 1,2,4-TCB. 3-oxo-C12:1-HSL appears to be the dominant AHL with the highest intensity and rapidly degraded by the bacterial community via two main consecutive reactions (lactone hydrolysis and decarboxylic reaction). These findings suggest that the integrated AHLs and their degraded products play a crucial role in biofilm formation and biomineralization of 1,2,4-TCB in culture.}, } @article {pmid28696066, year = {2017}, author = {Wood, TK}, title = {Strategies for combating persister cell and biofilm infections.}, journal = {Microbial biotechnology}, volume = {10}, number = {5}, pages = {1054-1056}, pmid = {28696066}, issn = {1751-7915}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/genetics/growth & development ; Bacterial Infections/drug therapy/*microbiology ; Bacterial Physiological Phenomena ; *Biofilms/drug effects ; Humans ; }, abstract = {Bacterial cells are constantly exposed to environmental stress; for example, almost all cells must endure starvation, and antimicrobials, of course, are administered to kill bacteria. These stressed cells enter a resting state known as persistence in which they become tolerant to nearly all antibiotics without undergoing genetic change. These dormant cells survive courses of antibiotics, as antibiotics are most effective against actively metabolizing cells, and reconstitute infections. In humans, most of these bacterial infections occur in biofilms in which bacteria attach to one another via secreted proteins, polysaccharides and even DNA. Herein, biotechnological methods are described to combat persister cells and to eradicate biofilms by understanding the genetic basis of both phenomena.}, } @article {pmid28694609, year = {2017}, author = {Benachinmardi, KK and Ravikumar, R and Indiradevi, B}, title = {Role of Biofilm in Cerebrospinal Fluid Shunt Infections: A Study at Tertiary Neurocare Center from South India.}, journal = {Journal of neurosciences in rural practice}, volume = {8}, number = {3}, pages = {335-341}, pmid = {28694609}, issn = {0976-3147}, abstract = {INTRODUCTION: Biofilms are the source of persistent infections of many pathogenic microbes. They are responsible for nosocomial infection and also associated with many surgical conditions including indwelling medical devices such as ventriculoperitoneal shunt. A significant problem encountered in shunt procedures is obstruction followed by infection, with infection rate ranging from 2% to 27%, often with poor outcome.

MATERIALS AND METHODS: This study was conducted in the Department of Neuromicrobiology at a tertiary neuroinstitute for 6 months from July 1 to December 31, 2014. The samples comprised cerebrospinal fluid (CSF) from suspected cases of shunt infections. Laboratory diagnosis of causative agent was established by adopting standard procedures. Then, isolates were evaluated for production of biofilm by tissue culture plate (TCP) method and tube method.

RESULTS: Of the 1642 shunt CSF samples obtained from neurosurgery, 14.79% were culture positive which yielded 254 isolates. About 51.97% were Gram-negative bacilli (GNB), 46.46% were Gram-positive cocci (GPC), and 1.57% were Candida albicans. Among GNB, nonfermenters were the most common (51.52%) followed by Pseudomonas aeruginosa (15.9%). Among GPC, coagulase-negative Staphylococci were 88.13%, out of which 43.26% were methicillin-resistant. Other GPC were Enterococcus spp. (4.24%), Staphylococcus aureus (5.08%), and Streptococcus spp. (2.54%). Among all isolates, 120 were tested for biofilm production, out of which 57.5% were biofilm producers and 42.5% were nonproducers.

CONCLUSIONS: TCP was the better method to detect biofilm. Most of the biofilm producers were resistant pathogens.}, } @article {pmid28691316, year = {2018}, author = {Muniz, FWMG and da Silva Lima, H and Rösing, CK and Martins, RS and Moreira, MMSM and Carvalho, RS}, title = {Efficacy of an unwaxed dental floss impregnated with 2% chlorhexidine on control of supragingival biofilm: A randomized, clinical trial.}, journal = {Journal of investigative and clinical dentistry}, volume = {9}, number = {1}, pages = {}, doi = {10.1111/jicd.12280}, pmid = {28691316}, issn = {2041-1626}, mesh = {Adolescent ; Adult ; Anti-Infective Agents, Local/administration & dosage/*therapeutic use ; Biofilms/*drug effects ; Brazil ; Chlorhexidine/administration & dosage/analogs & derivatives/*therapeutic use ; *Dental Devices, Home Care ; Dental Plaque/prevention & control/*therapy ; Dental Plaque Index ; Female ; Gingival Hemorrhage/therapy ; Gingivitis/prevention & control/*therapy ; Humans ; Male ; Oral Hygiene ; Periodontal Index ; Self Report ; Treatment Outcome ; Young Adult ; }, abstract = {AIM: In the present study, we evaluated the antiplaque and antigingivitis efficacy of a dental floss impregnated with 2% chlorhexidine digluconate.

METHODS: Thirty dental students were randomly divided into three groups (n=10): (a) negative control (NC) group, in which no interproximal cleaning was performed; (b) the positive control (PC) group, which used a standard unwaxed dental floss twice daily; and (c) and the test group, which used a unwaxed dental floss impregnated with 2% chlorhexidine twice daily. Six surfaces per tooth were evaluated by the Quigley-Hein plaque index (Turesky modification) at the last appointment (day 15), and testing for the presence of marginal bleeding was performed using the marginal bleeding index (MBI) at both the baseline and last appointments.

RESULTS: At day 15, the test group had the lowest mean plaque index (1.04±0.67), showing a statistically-significant difference compared to the NC group (1.40±0.65, P<.001) and PC group (2.30±0.73, P<.001). The PC and test groups showed a mean reduction of 70.2% and 87.26%, respectively, with significant reduction compared to baseline (P<.05) for the MBI. No statistically-significant difference was found between the PC and test groups (P=.126).

CONCLUSION: Unwaxed dental floss impregnated with 2% chlorhexidine showed additional reductions in supragingival interproximal biofilm compared with a conventional unwaxed dental floss, without additional improvement in marginal bleeding.}, } @article {pmid28690026, year = {2017}, author = {Chung, PY and Khanum, R}, title = {Antimicrobial peptides as potential anti-biofilm agents against multidrug-resistant bacteria.}, journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi}, volume = {50}, number = {4}, pages = {405-410}, doi = {10.1016/j.jmii.2016.12.005}, pmid = {28690026}, issn = {1995-9133}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Bacteria/*drug effects ; *Bacterial Physiological Phenomena ; Biofilms/*drug effects ; Humans ; }, abstract = {Bacterial resistance to commonly used drugs has become a global health problem, causing increased infection cases and mortality rate. One of the main virulence determinants in many bacterial infections is biofilm formation, which significantly increases bacterial resistance to antibiotics and innate host defence. In the search to address the chronic infections caused by biofilms, antimicrobial peptides (AMP) have been considered as potential alternative agents to conventional antibiotics. Although AMPs are commonly considered as the primitive mechanism of immunity and has been extensively studied in insects and non-vertebrate organisms, there is now increasing evidence that AMPs also play a crucial role in human immunity. AMPs have exhibited broad-spectrum activity against many strains of Gram-positive and Gram-negative bacteria, including drug-resistant strains, and fungi. In addition, AMPs also showed synergy with classical antibiotics, neutralize toxins and are active in animal models. In this review, the important mechanisms of action and potential of AMPs in the eradication of biofilm formation in multidrug-resistant pathogen, with the goal of designing novel antimicrobial therapeutics, are discussed.}, } @article {pmid28689132, year = {2017}, author = {Cai, W and Li, Y and Niu, L and Zhang, W and Wang, C and Wang, P and Meng, F}, title = {New insights into the spatial variability of biofilm communities and potentially negative bacterial groups in hydraulic concrete structures.}, journal = {Water research}, volume = {123}, number = {}, pages = {495-504}, doi = {10.1016/j.watres.2017.06.055}, pmid = {28689132}, issn = {1879-2448}, mesh = {*Biofilms ; Proteobacteria/*genetics ; RNA, Ribosomal, 16S ; Rivers ; Water Supply ; }, abstract = {The composition and distribution characteristics of bacterial communities in biofilms attached to hydraulic concrete structure (HCS) surfaces were investigated for the first time in four reservoirs in the middle and lower reaches of the Yangtze River Basin using 16S rRNA Miseq sequencing. High microbial diversity was found in HCS biofilms, and notable differences were observed in different types of HCS. Proteobacteria, Cyanobacteria and Chloroflexi were the predominant phyla, with respective relative abundances of 35.3%, 25.4% and 13.0%. The three most abundant genera were Leptolyngbya, Anaerolineaceae and Polynucleobacter. The phyla Beta-proteobacteria and Firmicutes and genus Lyngbya were predominant in CGP, whereas the phyla Cyanobacteria and Chloroflexi and genera Leptolyngbya, Anaerolinea and Polynucleobacter survived better in land walls and bank slopes. Dissolved oxygen, ammonia nitrogen and temperature were characterized as the main factors driving the bacterial community composition. The most abundant groups of metabolic functions were also identified as ammonia oxidizers, sulphate reducers, and dehalogenators. Additionally, functional groups related to biocorrosion were found to account for the largest proportion (14.0% of total sequences) in gate piers, followed by those in land walls (11.5%) and bank slopes (10.2%). Concrete gate piers were at the greatest risk of biocorrosion with the most abundant negative bacterial groups, especially for sulphate reducers. Thus, it should be paid high attention to the biocorrosion prevention of concrete gate piers. Overall, this study contributed to the optimization of microbial control and the improvement of the safety management for water conservation structures.}, } @article {pmid28688575, year = {2017}, author = {Townsley, L and Shank, EA}, title = {Natural-Product Antibiotics: Cues for Modulating Bacterial Biofilm Formation.}, journal = {Trends in microbiology}, volume = {25}, number = {12}, pages = {1016-1026}, pmid = {28688575}, issn = {1878-4380}, support = {R01 GM112981/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Bacteria/*metabolism ; Biofilms/*growth & development ; Biological Products/*metabolism ; Quorum Sensing ; Signal Transduction ; }, abstract = {Cell-cell communication enables bacteria to coordinate their behavior through the production, recognition, and response to chemical signals produced by their microbial neighbors. An important example of coordinated behavior in bacteria is biofilm formation, where individual cells organize into highly complex, matrix-encased communities that differentiate into distinct cell types and divide labor among individual cells. Bacteria rely on environmental cues to influence biofilm development, including chemical cues produced by other microbes. A multitude of recent studies have demonstrated that natural-product antibiotics at subinhibitory concentrations can impact biofilm formation in neighboring microbes, supporting the hypothesis that these compounds may have evolved as signaling molecules that mediate cell-cell interactions. In this review we discuss the role of antibiotics in modulating biofilm formation and interspecies communication in bacteria.}, } @article {pmid28687645, year = {2017}, author = {De, A and Liao, S and Bitoun, JP and Roth, R and Beatty, WL and Wu, H and Wen, ZT}, title = {Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {17}, pages = {}, pmid = {28687645}, issn = {1098-5336}, support = {R01 DE019452/DE/NIDCR NIH HHS/United States ; }, mesh = {Antigens, Bacterial/genetics/*metabolism ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cell Division ; Cell Wall/genetics/*metabolism ; Culture Media/chemistry/metabolism ; Gene Expression Regulation, Bacterial ; Streptococcus mutans/cytology/*enzymology/genetics/*physiology ; Transcription Factors/genetics/*metabolism ; Transferases/genetics/*metabolism ; }, abstract = {Streptococcus mutans is known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen. S. mutans strains deficient in rgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. The rgpG deficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, the rgpG mutant existed primarily in chains of swollen, "squarish" dividing cells. Deficiency of rgpG also causes significant reduction in biofilm formation (P < 0.01). Double and triple mutants with deficiency in brpA and/or psr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using the rgpG mutant. There were no major differences in growth rates between the wild-type strain and the rgpG brpA and rgpG psr double mutants, but the growth rate of the rgpG brpA psr triple mutant was reduced drastically (P < 0.001). Under transmission electron microscopy, both double mutants resembled the rgpG mutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, the rgpG mutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and the brpA and psr single mutants. These results suggest that RgpG in S. mutans plays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation by S. mutans, indicative of a significant role of RGP in cell division and biofilm formation in S. mutans These results are novel not only in S. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr in S. mutans are involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation in S. mutans This study reveals new potential targets to develop anticaries therapeutics.}, } @article {pmid28687321, year = {2017}, author = {Srinivasan, R and Santhakumari, S and Ravi, AV}, title = {In vitro antibiofilm efficacy of Piper betle against quorum sensing mediated biofilm formation of luminescent Vibrio harveyi.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {232-239}, doi = {10.1016/j.micpath.2017.07.001}, pmid = {28687321}, issn = {1096-1208}, mesh = {Aquaculture ; Biofilms/*drug effects ; Cell Survival/drug effects ; Locomotion/drug effects ; Luminescent Proteins/drug effects ; Microbial Sensitivity Tests ; Piper betle/*chemistry ; Plant Extracts/*pharmacology ; Polysaccharides/metabolism ; Quorum Sensing/*drug effects ; Vibrio/cytology/*drug effects ; Vibrio Infections ; }, abstract = {Vibrio harveyi is a potent biofilm former, which confers resistance to multiple antimicrobials, disinfectants, chemicals and biocides. The prevalence of biofilm mediated antibiotic resistance among aquatic bacterial pathogens stresses the search for novel alternative approach to treat vibriosis in aquaculture. Exploring suitable therapeutics from natural resources could be a novel area of research. Therefore, this work was executed to evaluate the inhibitory effect of Piper betle ethyl acetate extract (PBE) on bioluminescence production and biofilm formation of V. harveyi. Minimal inhibitory concentration (MIC) of PBE against planktonic V. harveyi was found to be 1600 μg ml[-1]; furthermore, PBE inhibited the quorum sensing (QS) mediated bioluminescence production and biofilm formation in V. harveyi upto 98 and 74% respectively, at its sub-MIC concentration of 400 μg ml[-1] without affecting their cell viability. Similar results were obtained for exopolysaccharides production and swimming motility related to biofilm formation of V. harveyi, where PBE reduced EPS production upto 64%. Light and confocal laser scanning microscopic analyses further confirmed that the PBE effectively prevented the initial attachment as well as microcolonies formation of V. harveyi biofilm, when compared to their untreated controls. This study demonstrates the promising antibiofilm activity of PBE and confirms the ethnopharmacological potential of this plant against V. harveyi infections.}, } @article {pmid28687320, year = {2017}, author = {He, X and Yuan, F and Lu, F and Yin, Y and Cao, J}, title = {Vancomycin-induced biofilm formation by methicillin-resistant Staphylococcus aureus is associated with the secretion of membrane vesicles.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {225-231}, doi = {10.1016/j.micpath.2017.07.004}, pmid = {28687320}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Secretion Systems/chemistry/*drug effects/metabolism/ultrastructure ; Biofilms/*drug effects/*growth & development ; Cell Aggregation/drug effects ; Cell Communication/drug effects ; Cell Culture Techniques ; Hydrophobic and Hydrophilic Interactions ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*physiology ; Microbial Sensitivity Tests ; Vancomycin/administration & dosage/*pharmacology ; }, abstract = {Chronic burn wound infections caused by Stapyhylococcus aureus (S. aureus) are largely associated with biofilm formation. However, the mechanism by which S. aureus form biofilm in clinical environments is far less understood. In the present study we addressed the association between biofilm formation and membrane vesicle (MV) secretion of S. aureus during vancomycin treatment. A representative methicillin-resistant S. aureus (MRSA) strain BWMR22 obtained from a chronic burn wound was used in this study. Transmission electron microscope was used to observe the MV secretion. Fourier transform infrared spectroscopy was used to analyze the chemical component of MV. Biofilm formation was assayed under conditions of sub-inhibitory concentrations of vancomycin. Functional potencies of MV in surface adhesion and auto-aggregation were assayed in the presence of additional purified MVs. Biofilm formation by S. aureus BWMR22 was enhanced in the presence of sub-inhibitory concentration of vancomycin. Vancomycin treatment caused an increase in the chemical composition of protein relative to carbohydrates of secreted MVs, a property which was highly associated with bacterial hydrophobicity, surface adhesion, and intercellular aggregation. These findings suggest that MV secretion is correlated with biofilm formation by MRSA especially under clinical conditions with improper vancomycin chemotherapy. This study first demonstrates a potential role of MVs in the biofilm formation by S. aureus, stresses on the importance of avoiding low dose of antibiotic therapy in controlling of S. aureus infections, and provides further information to reveal the mechanisms behind MRSA infections.}, } @article {pmid28686622, year = {2017}, author = {Luo, J and Lv, P and Zhang, J and Fane, AG and McDougald, D and Rice, SA}, title = {Succession of biofilm communities responsible for biofouling of membrane bio-reactors (MBRs).}, journal = {PloS one}, volume = {12}, number = {7}, pages = {e0179855}, pmid = {28686622}, issn = {1932-6203}, mesh = {Archaea/genetics/growth & development ; Bacteria/genetics/growth & development ; Biofilms/*growth & development ; *Biofouling ; Bioreactors ; Fungi/genetics/growth & development ; Membrane Potentials/genetics ; Pressure ; Sewage/*microbiology ; *Waste Disposal, Fluid ; }, abstract = {Biofilm formation is one of the main factors associated with membrane biofouling in membrane bioreactors (MBRs). As such, it is important to identify the responsible organisms to develop targeted strategies to control biofouling. This study investigated the composition and changes in the microbial communities fouling MBR membranes over time and correlated those changes with an increase in transmembrane pressure (TMP). Based on qPCR data, bacteria were the dominant taxa of the biofilm (92.9-98.4%) relative to fungi (1.5-6.9%) and archaea (0.03-0.07%). NMDS analysis indicated that during the initial stages of operation, the biofilm communities were indistinguishable from those found in the sludge. However, the biofilm community significantly diverged from the sludge over time and ultimately showed a unique biofilm profile. This suggested that there was strong selection for a group of organisms that were biofilm specialists. This pattern of succession and selection was correlated with the rapid increase in TMP, where bacteria including Rhodospirillales, Sphingomonadales and Rhizobiales dominated the biofilm at this time. While most of the identified fungal OTUs matched Candida sp., the majority of fungal communities were unclassified by 18S rRNA gene sequencing. Collectively, the data suggests that bacteria, primarily, along with fungi may play an important role in the rapid TMP increase and loss of system performance.}, } @article {pmid28686044, year = {2017}, author = {Bakkiyaraj, D and Sritharadol, R and Padmavathi, AR and Nakpheng, T and Srichana, T}, title = {Anti-biofilm properties of a mupirocin spray formulation against Escherichia coli wound infections.}, journal = {Biofouling}, volume = {33}, number = {7}, pages = {591-600}, doi = {10.1080/08927014.2017.1337100}, pmid = {28686044}, issn = {1029-2454}, mesh = {Acrylates/chemistry ; Administration, Cutaneous ; Aerosols ; Anti-Bacterial Agents/administration & dosage/*pharmacology/toxicity ; Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Drug Compounding ; Escherichia coli/*drug effects/isolation & purification ; Humans ; Mupirocin/administration & dosage/*pharmacology/toxicity ; Ointments ; Polymers/chemistry ; Skin Diseases, Bacterial/*drug therapy ; Staphylococcal Infections/*drug therapy ; Wound Infection/*drug therapy ; }, abstract = {Mupirocin ointment is a widely used topical drug for the treatment of bacterial skin infections. However, ointments have some limitations which motivated the development of a film forming spray of mupirocin. Mupirocin spray (2%) was formulated with Eudragit E100 as a film forming agent and tested for its antibacterial and anti-biofilm activities against Escherichia coli, a skin pathogen causing wound and surgical site infections. Treatment with mupirocin spray resulted in significant antibacterial and anti-biofilm activities (inhibition and disruption) with single spray and sub-actual dose concentrations at par with the commercial ointment concentration. The spray formulation was found to be non-toxic to fibroblast cells and greatly resisted removal from the site of application upon washing, in contrast to the ointment which was significantly removed after a single wash. This is the first study to develop and evaluate a spray formulation for mupirocin that forms a stable thin film for sustained release of the drug.}, } @article {pmid28686037, year = {2017}, author = {Artini, M and Cicatiello, P and Ricciardelli, A and Papa, R and Selan, L and Dardano, P and Tilotta, M and Vrenna, G and Tutino, ML and Giardina, P and Parrilli, E}, title = {Hydrophobin coating prevents Staphylococcus epidermidis biofilm formation on different surfaces.}, journal = {Biofouling}, volume = {33}, number = {7}, pages = {601-611}, doi = {10.1080/08927014.2017.1338690}, pmid = {28686037}, issn = {1029-2454}, mesh = {Acremonium/chemistry ; Bacterial Adhesion/*drug effects ; Biofilms/drug effects/*growth & development ; Fungal Proteins/*chemistry/isolation & purification/pharmacology ; Hydrophobic and Hydrophilic Interactions ; Microbial Viability/drug effects ; Microscopy, Atomic Force ; Microscopy, Confocal ; Pleurotus/chemistry ; Polystyrenes/*chemistry ; Staphylococcus epidermidis/drug effects/*growth & development/physiology ; Surface Properties ; }, abstract = {Staphylococcus epidermidis is a significant nosocomial pathogen in predisposed hosts because of its capability of forming a biofilm on indwelling medical devices. The initial stage of biofilm formation has a key role in S. epidermidis abiotic surface colonization. Recently, many strategies have been developed to create new anti-biofilm surfaces able to control bacterial adhesion mechanisms. In this work, the self-assembled amphiphilic layers formed by two fungal hydrophobins (Vmh2 and Pac3) have proven to be able to reduce the biofilm formed by different strains of S. epidermidis on polystyrene surfaces. The reduction in the biofilm thickness on the coated surfaces and the preservation of cell vitality have been demonstrated through confocal laser scanning microscope analysis. Moreover, the anti-biofilm efficiency of the self-assembled layers on different medically relevant materials has also been demonstrated using a CDC biofilm reactor.}, } @article {pmid28685594, year = {2017}, author = {Patel, B and Kumari, S and Banerjee, R and Samanta, M and Das, S}, title = {Disruption of the quorum sensing regulated pathogenic traits of the biofilm-forming fish pathogen Aeromonas hydrophila by tannic acid, a potent quorum quencher.}, journal = {Biofouling}, volume = {33}, number = {7}, pages = {580-590}, doi = {10.1080/08927014.2017.1336619}, pmid = {28685594}, issn = {1029-2454}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Aeromonas hydrophila/*drug effects/genetics/pathogenicity/physiology ; Animals ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Chromobacterium/physiology ; Cyprinidae/*microbiology ; Dose-Response Relationship, Drug ; Down-Regulation ; Quorum Sensing/*drug effects ; Tannins/*pharmacology ; Virulence/drug effects ; }, abstract = {The quorum sensing (QS) phenomenon regulates a myriad of pathogenic traits in the biofilm forming fish pathogen, Aeromonas hydrophila. Blocking the QS mechanism of A. hydrophila is a novel strategy to prevent disease in fish. This study evaluated the effect of tannic acid, a QS inhibitor, on A. hydrophila-associated QS regulated phenomena. A streaking assay with Chromobacterium violaceum (CVO26) reported the presence of N-acyl homoserine lactone (AHL) in A. hydrophila, which was confirmed by HPLC and GC-MS analysis. Tannic acid-treated A. hydrophila showed a considerable reduction in violacein production, blood haemolysis activity and the pattern of swarming motility. Biofilm formation was significantly reduced (p < 0.001) (up to 95%), after tannic acid treatment for 48 h. Analysis by qRT-PCR revealed significant downregulation (p < 0.001) of AhyI and AhyR transcripts in A. hydrophila after tannic acid treatment. Co-stimulation of Catla catla with A. hydrophila and tannic acid attenuated pathogen-induced skin haemorrhages and increased the relative survival rate up to 86.6%. The study provides a mechanistic basis of tannic acid as a QS blocker and indicates its therapeutic potential against A. hydrophila-induced pathogenesis.}, } @article {pmid28685097, year = {2017}, author = {Dale, JL and Nilson, JL and Barnes, AMT and Dunny, GM}, title = {Restructuring of Enterococcus faecalis biofilm architecture in response to antibiotic-induced stress.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {15}, pmid = {28685097}, issn = {2055-5008}, support = {R01 AI058134/AI/NIAID NIH HHS/United States ; R01 AI122742/AI/NIAID NIH HHS/United States ; R56 AI058134/AI/NIAID NIH HHS/United States ; T32 HL007741/HL/NHLBI NIH HHS/United States ; }, abstract = {Bacterial biofilms are intrinsically resistant to antimicrobial treatment, which contributes to microbial persistence in clinical infections. Enterococcus faecalis is an opportunistic pathogen that readily forms biofilms and is the most prevalent enterococcal species identified in healthcare-associated infections. Since intrinsic resistance to multiple antibiotics is common for enterococci, and antibiotic resistance is elevated in biofilm populations, it is imperative to understand the mechanisms involved. Previously, we identified two glycosyltransferase genes whose disruption resulted in impaired nascent biofilm formation in the presence of antibiotic concentrations subinhibitory for parent growth and biofilm formation. The glycosyltransferases are involved in synthesis of the cell-wall-associated rhamnopolysaccharide Epa. Here we examined the effect of epa mutations on the temporal development of E. faecalis biofilms, and on the effects of antibiotics on pre-formed biofilms using scanning electron microscopy. We show that ΔepaOX mutant cells arrange into complex multidimensional biofilms independent of antibiotic exposure, while parent cells form biofilms that are monolayers in the absence of antibiotics. Remarkably, upon exposure to antibiotics parent biofilm cells restructure into complex three-dimensional biofilms resembling those of the ΔepaOX mutant without antibiotics. All biofilms exhibiting complex cellular architectures were less structurally stable than monolayer biofilms, with the biofilm cells exhibiting increased detachment. Our results indicate that E. faecalis biofilms restructure in response to cellular stress whether induced by antibiotics in the case of parent cells, or by deficiencies in Epa composition for the ΔepaOX strain. The data demonstrate a link between cellular architecture and antibiotic resistance of E. faecalis biofilms.}, } @article {pmid28684253, year = {2017}, author = {George, J and Halami, PM}, title = {Sub-inhibitory concentrations of gentamicin triggers the expression of aac(6')Ie-aph(2″)Ia, chaperons and biofilm related genes in Lactobacillus plantarum MCC 3011.}, journal = {Research in microbiology}, volume = {168}, number = {8}, pages = {722-731}, doi = {10.1016/j.resmic.2017.06.002}, pmid = {28684253}, issn = {1769-7123}, mesh = {Acetyltransferases/*genetics/metabolism ; Aminoglycosides/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Biofilms/drug effects ; Chaperonin 60/*genetics/metabolism ; Chickens ; Gentamicins/*pharmacology ; Lactobacillus plantarum/*drug effects/enzymology/genetics/physiology ; Meat Products/microbiology ; Phosphotransferases (Alcohol Group Acceptor)/*genetics/metabolism ; }, abstract = {The study aimed to analyze the effects of sub-inhibitory concentrations of gentamicin on the expressions of high level aminoglycoside resistant (HLAR) bifunctional aac(6')Ie-aph(2″)Ia, biofilm and chaperone genes in Lactobacillus plantarum. The analysis of the biofilm formation in five isolates obtained from chicken sausages indicated their role in exhibiting phenotypic resistance based on the varied MIC values despite carrying the bifunctional gene. The biofilm formation significantly increased when L. plantarum MCC 3011 was grown in sub-inhibitory concentrations of gentamicin (4 μg/ml), kanamycin (8 μg/ml) and streptomycin (2 μg/ml). Thirty day gentamicin selection increased minimum inhibitory concentration (MIC) values from 4 to 64 and 2 to 256 fold for gentamicin and kanamycin, respectively when compared to the parental cultures. Expression studies revealed that constant exposure to gentamicin had induced chaperon [groEL] and the bifunctional gene, aac(6')Ie-aph(2″)Ia upto nine fold. Induction of groEL, groES and lamC genes in gentamicin (4 μg/ml) preincubated MCC 3011 indicated their significant role in aminoglycoside mediated response. Our study indicates that constant exposure to sub inhibitory concentrations of gentamicin allows L. plantarum to adapt against higher doses of aminoglycosides. This highlights the risks and food safety issues associated with the use of aminoglycosides in livestock and consumption of farm oriented fermented food products.}, } @article {pmid28683522, year = {2017}, author = {Lim, ES and Kim, JS}, title = {Role of eptC in Biofilm Formation by Campylobacter jejuni NCTC11168 on Polystyrene and Glass Surfaces.}, journal = {Journal of microbiology and biotechnology}, volume = {27}, number = {9}, pages = {1609-1616}, doi = {10.4014/jmb.1610.10046}, pmid = {28683522}, issn = {1738-8872}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Campylobacter jejuni/*metabolism ; Glass/*chemistry ; Membrane Proteins/*metabolism ; Polystyrenes/*chemistry ; Stem Cells ; }, abstract = {The complex roles of cell surface modification in the biofilm formation of Campylobacter jejuni, a major cause of worldwide foodborne diarrheal disease, are poorly understood. In a screen of mutants from random transposon mutagenesis, an insertional mutation in the eptC gene (cj0256) resulted in a significant decrease in C. jejuni NCTC11168 biofilm formation (<20%) on major food contact surfaces, such as polystyrene and borosilicate glass, when compared with wild-type cells (p < 0.05). In C. jejuni strain 81-176, the protein encoded by eptC modified cell surface structures, such as lipid A, the inner core of lipooligosaccharide, and the flagellar rod protein (FlgG), by attaching phosphoethanolamine. To assess the role of eptC in C. jejuni NCTC11168, adherence and motility tests were performed. In adhesion assays with glass surfaces, the eptC mutant exhibited a 0.77 log CFU/cm[2] decrease in adherence compared with wild-type cells during the initial 2 h of the assay (p < 0.05). These results support the hypothesis that the modification of cell surface structures by eptC affects the initial adherence in biofilm formation of C. jejuni NCTC11168. In motility tests, the eptC mutant demonstrated reduced motility when compared with wild-type cells, but wild-type cells with the transposon inserted in a gene irrelevant to biofilm formation (cj1111c) also exhibited decreased motility to a similar extent as the eptC mutant. This suggests that although eptC affects motility, it does not significantly affect biofilm formation. This study demonstrates that eptC is essential for initial adherence, and plays a significant role in the biofilm formation of C. jejuni NCTC11168.}, } @article {pmid28682297, year = {2017}, author = {Snyder, RJ and Bohn, G and Hanft, J and Harkless, L and Kim, P and Lavery, L and Schultz, G and Wolcott, R}, title = {Wound Biofilm: Current Perspectives and Strategies on Biofilm Disruption and Treatments.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {29}, number = {6}, pages = {S1-S17}, pmid = {28682297}, issn = {1943-2704}, mesh = {Administration, Topical ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects/growth & development ; Debridement/*methods ; Evidence-Based Medicine ; Humans ; Practice Guidelines as Topic ; Wound Healing/drug effects/*physiology ; Wound Infection/*microbiology/*therapy ; }, abstract = {The presence of bio lm remains a challenging factor that contributes to the delayed healing of many chronic wounds. The major threat of chronic wound bio lms is their substantial protection from host immunities and extreme tolerance to antimicrobial agents. To help guide the development of wound treatment strategies, a panel of experts experienced in clinical and laboratory aspects of biofilm convened to discuss what is understood and not yet understood about biofilms and what is needed to better identify and treat chronic wounds in which biofilm is suspected. This article reviews evidence of the problem of biofilms in chronic wounds, summarizes literature-based and experience-based recommendations from the panel meeting, and identities future and emerging technologies needed to address the current gaps in knowledge. While currently there is insufficient evidence to provide an accurate comparison of the effectiveness of current therapies/products in reducing or removing biofilm, research has shown that in addition to debridement, appropriate topical antimicrobial application can suppress biofilm reformation. Because the majority of the resistance of bacteria in a biofilm population is expressed by its own secreted matrix of extracellular polymeric substance (EPS), panel members stressed the need for a paradigm shift toward biofilm treatment strategies that disrupt this shield. High-osmolarity surfactant solution technology is emerging as a potential multimodal treatment that has shown promise in EPS disruption and prevention of biofilm formation when used immediately post debridement. Panel members advocated incorporating an EPS-disrupting technology into an antibiofilm treatment approach for all chronic wounds. The activity of this panel is a step toward identifying technology and research needed to improve biofilm management of chronic wounds.}, } @article {pmid28681017, year = {2016}, author = {Sadeghi Ardestani, Z and Falahati, M and Sayah Alborzi, S and Ashrafi Khozani, M and Rostam Khani, F and Bahador, A}, title = {The effect of nanochitosans particles on Candida biofilm formation.}, journal = {Current medical mycology}, volume = {2}, number = {2}, pages = {28-33}, pmid = {28681017}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: In people wearing dentures, the growth of various Candida species under the prosthesis leads to the formation of biofilm, which can play the role of a reservoir for Candida and other kinds of microbes. Since nano-chitosan particles can cause lasting antimicrobial activity, a more recent approach that utilizes acrylic resins with nano-chitosan particles is proposed. Therefore, we aimed to study the inhibitory effect of nano-chitosan particles on the biofilm formation of Candida species in acrylic resins.

MATERIALS AND METHODS: In this analytical in-vitro study, acrylic resins with nano-chitosan particles with concentrations of 0, 1%, 5%, and %10 were put adjacent to the suspension of Candida cells isolated from the individuals' mouth and biofilm formation on resins was measured and compared. Finally, the data were analyzed using Kruskal-Wallis and Chi-square tests.

RESULTS: The observed differences between unmodified acrylic resin (control) and acrylic resin with nano-chitosan particles in terms of biofilm formation were significant (P<0.05) but no significant difference was found in the formation of biofilm species on resins.

CONCLUSION: Biofilm formation of Candida species depends on acrylic resin type, in a way that by adding nano-chitosan particles to acrylic resins, biofilm formation of Candida species was significantly reduced. To decrease the organization of biofilm and denture stomatitis, the use of acrylics with nano-chitosan particles in producing dentures is recommended.}, } @article {pmid28681014, year = {2016}, author = {Vijayalakshmi, P and Thenmozhi, S and Rajeswari, P}, title = {The Evaluation of the virulence factors of clinical Candida isolates and the anti-biofilm activity of Elettaria cardamomum against multi-drug resistant Candida albicans.}, journal = {Current medical mycology}, volume = {2}, number = {2}, pages = {8-15}, pmid = {28681014}, issn = {2423-3439}, abstract = {BACKGROUND AND PURPOSE: Today, treatment of life-threatening fungal infections, caused by Candida species, has become a major problem. In the present study, we aimed to evaluate the antifungal susceptibility patterns of different clinical Candida isolates, determine the virulence factors in multi-drug resistant (MDR) Candida species, and assess the anti-biofilm activity of Elettaria cardamomum against MDR Candida species.

MATERIALS AND METHODS: A total of 202 isolates from different Candida species were obtained from three governmental hospitals in Senthamangalam, Tiruchengode, and Namakkal, Tamil Nadu, India. The isolates were identified, using conventional methods. Candida species were tested for virulence factors such as biofilm, protease, and phospholipase activity. The minimum inhibitory concentration (MIC) of Elettaria cardamomum against MDR biofilm-forming C. albicans was determined, using plate and tube methods.

RESULTS: The identified Candida isolates (n=202) were C. albicans (74/202), C. glabrata (53/202), C. parapsilosis (44/202), C. tropicalis (15/202), and C. dubliniensis (16/202). The isolates were subjected to antifungal susceptibility testing and the virulence factors were determined. In terms of biofilm production, non-C. albicans species such as C. dubliniensis showed 75% activity. Also, regarding protease activity, C. parapsilosis (75%) showed the highest percentage of protease production. In addition, Candida species showed strong positivity for phospholipase activity (62.87%). In the MIC method, the acetonic extract completely inhibited biofilm production at a concentration of 125 µl (56.25 µg). In comparison with the ethanolic extract, the acetonic extract showed major activity against biofilm production.

CONCLUSION: Based on the findings, pathogenic C. albicans species were inhibited by the ethanolic and acetonic extracts of E. cardamomum. In recent years, MDR and biofilm-forming pathogenic Candida species have been increasingly detected in clinical settings. Therefore, herbal derivatives might contribute to the treatment of infections without causing any side-effects and prevent the associated mortality.}, } @article {pmid28680858, year = {2017}, author = {Bielen, K and 's Jongers, B and Boddaert, J and Raju, TK and Lammens, C and Malhotra-Kumar, S and Jorens, PG and Goossens, H and Kumar-Singh, S}, title = {Biofilm-Induced Type 2 Innate Immunity in a Cystic Fibrosis Model of Pseudomonas aeruginosa.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {274}, pmid = {28680858}, issn = {2235-2988}, mesh = {Animals ; *Biofilms/growth & development ; Cystic Fibrosis/complications/*immunology ; Cytokines/metabolism ; Disease Models, Animal ; Eosinophils ; Host-Parasite Interactions/immunology ; Humans ; *Immunity, Innate ; Immunohistochemistry ; Lung/immunology/microbiology/pathology ; Macrophages/metabolism ; Male ; Pseudomonas Infections/*immunology ; Pseudomonas aeruginosa/*pathogenicity ; Rats ; Rats, Wistar ; Th17 Cells/immunology ; Th2 Cells/*immunology ; }, abstract = {Biofilm-producing strains of Pseudomonas aeruginosa are a major cause of morbidity and mortality in cystic fibrosis (CF) patients. In these patients, increased levels of IL-17 as well as of IL-5 and IL-13 along with arginase (Arg)-positive macrophages have been observed in bronchoalveolar lavage fluid. While IL-17 is a strong proinflammatory cytokine associated with host defense against bacterial and fungal infections and is also elevated in several autoimmune diseases, IL-5/IL-13 and Arg1-positive M2 macrophages are part of the anti-inflammatory type 2 (Th2) immunity. To study whether increased IL-5 and IL-13 levels are related to biofilm formation, which is frequently observed in CF patients colonized by P. aeruginosa, we utilized an agarose bead-embedded P. aeruginosa rat model commonly employed in in vivo biofilm studies. We showed that "sterile" agarose bead instillation in rat notably increased lung transcript levels of IL-5 and IL-13 at two post-instillation study-points, day 1 and day 3. Concurrently, increased infiltration of type 2 innate cells such as eosinophils and Arg1 positive M2 activated macrophages (Arg1+CD68+) was also observed both at day 1 and day 3 while the proportion of M1 activated macrophages (iNOS+CD68+) at these time-points decreased. In contrast, P. aeruginosa-loaded beads caused a drastic elevation of proinflammatory Th1 (IFNγ, TNFα, IL-12a) and antibacterial Th17 (IL-17a, IL-17f, IL-22, IL-23a) cytokines along with a high influx of neutrophils and M1 macrophages, while Th2 cytokines (IL-5 and IL-13) drastically declined at day 1 post-infection. Interestingly, at day 3 post-infection, both Th1 and Th17 cytokines sharply declined and corroborated with decreased M1 and increased M2 macrophages. These data suggest that while IL-17 is linked to episodes of acute exacerbations of infection in CF patients, the increased Th2 cytokines and M2 macrophages observed in these patients are largely due to the biofilm matrix. The data presented here has important implications for clinical management of CF patients.}, } @article {pmid28680041, year = {2017}, author = {Liu, W and Tian, XQ and Wei, JW and Ding, LL and Qian, W and Liu, Z and Wang, FF}, title = {BsmR degrades c-di-GMP to modulate biofilm formation of nosocomial pathogen Stenotrophomonas maltophilia.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {4665}, pmid = {28680041}, issn = {2045-2322}, mesh = {Bacterial Proteins/chemistry/*genetics/*metabolism ; Binding Sites ; Biofilms/*growth & development ; Cross Infection ; Cyclic GMP/*analogs & derivatives/chemistry ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; High-Throughput Nucleotide Sequencing ; Operon ; Phosphorylation ; Promoter Regions, Genetic ; Protein Binding ; Sequence Analysis, RNA ; Signal Transduction ; Stenotrophomonas maltophilia/genetics/*growth & development/metabolism ; }, abstract = {c-di-GMP is a cellular second messenger that regulates diverse bacterial processes, including swimming, biofilm formation and virulence. However, in Stenotrophomonas maltophilia, a nosocomial pathogen that frequently infects immunodeficient or immunoincompetent patients, the regulatory function of c-di-GMP remains unclear. Here we show that BsmR is a negative regulator of biofilm development that degrades c-di-GMP through its EAL domain. Increasing BsmR expression resulted in significant increase in bacterial swimming and decrease in cell aggregation. BsmR regulates the expression of at least 349 genes. Among them, 34 involved in flagellar assembly and a flagellar-assembly-related transcription factor (fsnR) are positively regulated. Although BsmR is a response regulator of the two-component signaling system, its role in biofilm formation depends on the expression level of its respective gene (bsmR), not on the protein's phosphorylation level. A transcription factor, BsmT, whose coding gene is located in the same tetra-cistronic operon as bsmR, was shown to directly bind to the promoter region of the operon and, through a positive regulatory loop, modulate bsmR transcription. Thus, our results revealed that the c-di-GMP signaling pathway controls biofilm formation and swimming in S. maltophilia, suggesting c-di-GMP signaling as a target in the development of novel antibacterial agents to resist this pathogen.}, } @article {pmid28679111, year = {2017}, author = {Baudin, M and Cinquin, B and Sclavi, B and Pareau, D and Lopes, F}, title = {Understanding the fundamental mechanisms of biofilms development and dispersal: BIAM (Biofilm Intensity and Architecture Measurement), a new tool for studying biofilms as a function of their architecture and fluorescence intensity.}, journal = {Journal of microbiological methods}, volume = {140}, number = {}, pages = {47-57}, doi = {10.1016/j.mimet.2017.06.021}, pmid = {28679111}, issn = {1872-8359}, mesh = {Bacteriological Techniques/instrumentation/methods ; Biofilms/drug effects/*growth & development ; Escherichia coli/drug effects/genetics/*physiology ; Fatty Acids, Monounsaturated/pharmacology ; Fluorescence ; Microscopy, Confocal/*methods ; Promoter Regions, Genetic ; *Software ; }, abstract = {Confocal laser scanning microscopy (CLSM) is one of the most relevant technologies for studying biofilms in situ. Several tools have been developed to investigate and quantify the architecture of biofilms. However, an approach to quantify correctly the evolution of intensity of a fluorescent signal as a function of the structural parameters of a biofilm is still lacking. Here we present a tool developed in the ImageJ open source software that can be used to extract both structural and fluorescence intensity from CLSM data: BIAM (Biofilm Intensity and Architecture Measurement). This is of utmost significance when studying the fundamental mechanisms of biofilm growth, differentiation and development or when aiming to understand the effect of external molecules on biofilm phenotypes. In order to provide an example of the potential of such a tool in this study we focused on biofilm dispersion. cis-2-Decenoic acid (CDA) is a molecule known to induce biofilm dispersion of multiple bacterial species. The mechanisms by which CDA induces dispersion are still poorly understood. To investigate the effects of CDA on biofilms, we used a reporter strain of Escherichia coli (E. coli) that expresses the GFPmut2 protein under control of the rrnBP1 promoter. Experiments were done in flow cells and image acquisition was made with CLSM. Analysis carried out using the new tool, BIAM, indicates that CDA affects the fluorescence intensity of the biofilm structures as well as biofilm architectures. Indeed, our results demonstrate that CDA removes more than 35% of biofilm biovolume and suggest that it results in an increase of the biofilm's mean fluorescence intensity (MFI) by more than 26% compared to the control biofilm in the absence of CDA.}, } @article {pmid28677348, year = {2017}, author = {Huertas-Rosales, Ó and Romero, M and Heeb, S and Espinosa-Urgel, M and Cámara, M and Ramos-González, MI}, title = {The Pseudomonas putida CsrA/RsmA homologues negatively affect c-di-GMP pools and biofilm formation through the GGDEF/EAL response regulator CfcR.}, journal = {Environmental microbiology}, volume = {19}, number = {9}, pages = {3551-3566}, pmid = {28677348}, issn = {1462-2920}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/metabolism ; *Gene Expression Regulation, Bacterial ; Phosphorus-Oxygen Lyases/metabolism ; Pseudomonas putida/genetics/*metabolism ; RNA-Binding Proteins/genetics/*metabolism ; Repressor Proteins/genetics/*metabolism ; }, abstract = {Expression of cfcR, encoding the only GGDEF/EAL response regulator in Pseudomonas putida, is transcriptionally regulated by RpoS, ANR and FleQ, and the functionality of CfcR as a diguanylate cyclase requires the multisensor CHASE3/GAF hybrid histidine kinase named CfcA. Here an additional level of cfcR control, operating post-transcriptionally via the RNA-binding proteins RsmA, RsmE and RsmI, is unraveled. Specific binding of the three proteins to an Rsm-binding motif (5'CANGGANG3') encompassing the translational start codon of cfcR was confirmed. Although RsmA exhibited the highest binding affinity to the cfcR transcript, single deletions of rsmA, rsmE or rsmI caused minor derepression in CfcR translation compared to a ΔrsmIEA triple mutant. RsmA also showed a negative impact on c-di-GMP levels in a double mutant ΔrsmIE through the control of cfcR, which is responsible for most of the free c-di-GMP during stationary phase in static conditions. In addition, a CfcR-dependent c-di-GMP boost was observed during this stage in ΔrsmIEA confirming the negative effect of Rsm proteins on CfcR translation and explaining the increased biofilm formation in this mutant compared to the wild type. Overall, these results suggest that CfcR is a key player in biofilm formation regulation by the Rsm proteins in P. putida.}, } @article {pmid28676995, year = {2017}, author = {Zhao, J and Feng, L and Dai, J and Yang, G and Mu, J}, title = {Characteristics of nitrogen removal and microbial community in biofilm system via combination of pretreated lignocellulosic carriers and various conventional fillers.}, journal = {Biodegradation}, volume = {28}, number = {5-6}, pages = {337-349}, doi = {10.1007/s10532-017-9800-2}, pmid = {28676995}, issn = {1572-9729}, mesh = {Bacteria/genetics/isolation & purification/*metabolism ; Biodegradation, Environmental ; Biodiversity ; Biofilms ; Bioreactors/*microbiology ; Denitrification ; Environmental Restoration and Remediation/instrumentation/*methods ; Lignin/*chemistry/metabolism ; Nitrates/*metabolism ; Nitrogen/metabolism ; Water Purification/methods ; }, abstract = {Each kind of conventional plastic filler (polyurethane filler, SPR-1 suspension filler, TA-II elastic filler and sphere filler) coupled with alkaline pretreated corncob (A.H.corncob) was applied in each bioreactor system for treating polluted water with nitrate and organics. Results demonstrated that addition of A.H.corncob could achieve simultaneous removal of nitrogen and organics, and coupling of SPR-1 suspension filler with A.H.corncob (R2) had the best performance. In coupling system of R2, the total nitrogen (TN) removal rate improved from below 10% to 55.92 ± 18.27% with effluent CODMn concentration maintaining at a low level of 2.67 ± 0.44 mg L[-1]. Microbial analysis of combined filler system demonstrated that conventional plastic filler mainly accumulated non-solid-phase denitrifiers for both nitrate and organics removal including genera Salipiger, Enterobacteriaceae etc. while A.H.corncob carrier was stronghold of solid-phase denitrifiers (Runella, etc.) directly using lignocellulosic materials as carbon source and fermentative bacteria (Coprococcus, etc.) for supplementing available carbon sources for denitrifiers in the system, which were integrated to achieve simultaneous removal of nitrate and organics.}, } @article {pmid28676513, year = {2017}, author = {Wong, SS and Lau, WY and Chan, PK and Wan, CK and Cheng, YL}, title = {Antibiotic Lock in Tenckhoff Catheter for Biofilm-Associated Peritonitis.}, journal = {Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis}, volume = {37}, number = {4}, pages = {475-477}, doi = {10.3747/pdi.2016.00252}, pmid = {28676513}, issn = {1718-4304}, mesh = {Aged ; Anti-Bacterial Agents/*therapeutic use ; *Biofilms ; Catheter-Related Infections/etiology/*prevention & control ; Catheterization ; Catheters, Indwelling/*adverse effects ; Female ; Humans ; Kidney Failure, Chronic/therapy ; Middle Aged ; Peritoneal Dialysis, Continuous Ambulatory/adverse effects/*instrumentation ; Peritonitis/etiology/*prevention & control ; }, abstract = {Biofilm bacteria in the Tenckhoff catheter are notoriously difficult to eradicate. They are the potential sources of relapsing or repeat peritonitis among peritoneal dialysis (PD) patients. Inadequate penetration into biofilms by standard intraperitoneal antibiotics, as well as a lack of effective adjunctive treatment, leads to a high rate of Tenckhoff catheter loss as a result of biofilm bacteria. In hemodialysis, on the other hand, catheter-related bloodstream infection caused by biofilm bacteria does not necessarily lead to a loss of catheter. Here, the use of antibiotic lock in conjunction with systemic antibiotics has been shown to be an effective treatment. In this case report, we present 2 cases of biofilm-associated PD peritonitis. The success in salvaging the Tenckhoff catheters by antibiotic lock suggested a potentially similar efficacy in PD patients using this adjunctive treatment, which has not been thoroughly investigated in the literature. Relevant clinical trials are necessary to evaluate whether antibiotic lock is also effective in eradicating biofilm bacteria in the Tenckhoff catheter.}, } @article {pmid28675050, year = {2017}, author = {Nolte, KA and Schwarze, J and Rosenhahn, A}, title = {Microfluidic accumulation assay probes attachment of biofilm forming diatom cells.}, journal = {Biofouling}, volume = {33}, number = {7}, pages = {531-543}, doi = {10.1080/08927014.2017.1328058}, pmid = {28675050}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; *Biofouling ; Diatoms/*growth & development/physiology ; Hydrodynamics ; Microfluidics/*methods ; *Models, Theoretical ; Polystyrenes/chemistry ; Surface Properties ; Water Movements ; }, abstract = {Testing of fouling release (FR) technologies is of great relevance for discovery of the next generation of protective marine coatings. In this paper, an accumulation assay to test diatom interaction under laminar flow with the model organism Navicula perminuta is introduced. Using time lapse microscopy with large area sampling allows determination of the accumulation kinetics of the diatom on three model surfaces with different surface properties at different wall shear stresses. The hydrodynamic conditions within the flow cell are described and a suitable shear stress range to perform accumulation experiments is identified at which statistically significant discrimination of surfaces is possible. The observed trends compare well to published adhesion preferences of N. perminuta. Also, previously determined trends of critical wall shear stresses required for cell removal from the same set of functionalized interfaces shows consistent trends. Initial attachment mediated by extracellular polymeric substances (EPS) present outside the diatoms leads to the conclusion that the FR potential of the tested coating candidates can be deducted from dynamic accumulation experiments under well-defined hydrodynamic conditions. As well as testing new coating candidates for their FR properties, monitoring of the adhesion process under flow provides additional information on the mechanism and geometry of attachment and the population kinetics.}, } @article {pmid28674774, year = {2018}, author = {Fujimoto, M and Lovett, B and Angoshtari, R and Nirenberg, P and Loch, TP and Scribner, KT and Marsh, TL}, title = {Antagonistic Interactions and Biofilm Forming Capabilities Among Bacterial Strains Isolated from the Egg Surfaces of Lake Sturgeon (Acipenser fulvescens).}, journal = {Microbial ecology}, volume = {75}, number = {1}, pages = {22-37}, pmid = {28674774}, issn = {1432-184X}, mesh = {Animals ; *Antibiosis ; Bacteria/classification/genetics/*isolation & purification ; Bacterial Physiological Phenomena ; *Biofilms ; Fishes/*microbiology ; Lakes/microbiology ; Ovum/*microbiology ; Phylogeny ; }, abstract = {Characterization of interactions within a host-associated microbiome can help elucidate the mechanisms of microbial community formation on hosts and can be used to identify potential probiotics that protect hosts from pathogens. Microbes employ various modes of antagonism when interacting with other members of the community. The formation of biofilm by some strains can be a defense against antimicrobial compounds produced by other taxa. We characterized the magnitude of antagonistic interactions and biofilm formation of 25 phylogenetically diverse taxa that are representative of isolates obtained from egg surfaces of the threatened fish species lake sturgeon (Acipenser fulvescens) at two ecologically relevant temperature regimes. Eight isolates exhibited aggression to at least one other isolate. Pseudomonas sp. C22 was found to be the most aggressive strain, while Flavobacterium spp. were found to be one of the least aggressive and the most susceptible genera. Temperature affected the prevalence and intensity of antagonism. The aggressive strains identified also inhibited growth of known fish pathogens. Biofilm formations were observed for nine isolates and were dependent on temperature and growth medium. The most aggressive of the isolates disrupted biofilm formation of two well-characterized isolates but enhanced biofilm formation of a fish pathogen. Our results revealed the complex nature of interactions among members of an egg associated microbial community yet underscored the potential of specific microbial populations as host probiotics.}, } @article {pmid28674705, year = {2017}, author = {Fernández, E and Sánchez, MDC and Llama-Palacios, A and Sanz, M and Herrera, D}, title = {Antibacterial Effects of Toothpastes Evaluated in an In Vitro Biofilm Model.}, journal = {Oral health & preventive dentistry}, volume = {15}, number = {3}, pages = {251-257}, doi = {10.3290/j.ohpd.a38526}, pmid = {28674705}, issn = {1602-1622}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Azides/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Models, Biological ; Propidium/administration & dosage/*analogs & derivatives/pharmacology ; Sodium Fluoride/administration & dosage/*pharmacology ; Tin Fluorides/administration & dosage/*pharmacology ; *Toothpastes ; Triclosan/administration & dosage/*pharmacology ; }, abstract = {PURPOSE: To test the antibacterial effects of different toothpastes with the slurry method of toothpaste application in an in vitro oral biofilm model including relevant periodontal pathogens.

MATERIALS AND METHODS: Four commercially available toothpastes, two containing sodium fluoride (NaF) at different concentrations (1450 and 2500 ppm), two NaF with either triclosan or stannous fluoride, and a control phosphate-buffered saline (PBS) were used. Multispecies biofilms containing 6 species of oral bacteria were grown on hydroxyapatite disks for 72 h and then exposed for 2 min to the toothpaste slurries or phosphate buffer saline (PBS) by immersion, under continuous agitation at 37°C. Biofilms were then analysed by means of real-time polymerase chain reaction (PCR), combined with propidium monoazide (PMA). Statistical evaluation was performed using ANOVA and Student's t-test, with Bonferroni correction for multiple comparisons.

RESULTS: The toothpastes containing NaF and stannous fluoride demonstrated superior antimicrobial activity for A. actinomycetencomitans, P. gingivalis and F. nucleatum when compared to those containing NaF and triclosan, 1450 ppm NaF or 2500 ppm NaF in this multispecies biofilm model.

CONCLUSION: The proposed model for the evaluation of toothpastes in the form of slurries detected significant differences in the antimicrobial effects among the tested NaF-containing toothpastes, with the stannous fluoride-based formulation achieving better results than the other formulations. The use of toothpaste as slurries and real-time PCR with PMA is an adequate method for comparing the in vitro antimicrobial effect of different toothpastes.}, } @article {pmid28674314, year = {2017}, author = {Kawai, A and Yamagishi, Y and Mikamo, H}, title = {Time-Lapse Tracking of Candida tropicalis Biofilm Formation and the Antifungal Efficacy of Liposomal Amphotericin B.}, journal = {Japanese journal of infectious diseases}, volume = {70}, number = {5}, pages = {559-564}, doi = {10.7883/yoken.JJID.2016.574}, pmid = {28674314}, issn = {1884-2836}, mesh = {Amphotericin B/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Candida tropicalis/*drug effects/isolation & purification/*physiology ; Candidiasis/microbiology ; Gases/metabolism ; Humans ; Hyphae/growth & development ; Japan ; *Time-Lapse Imaging ; }, abstract = {Candida species bloodstream infection, or candidemia, remains an important health issue with high morbidity and mortality. Bloodstream infections caused by Candida species are often associated with the ability of Candida to form biofilms on medical devices, such as central venous catheters. Non-albicans Candida species have been increasing gradually in clinical settings. Another Candida species, C. tropicalis, has a propensity to form biofilms and is also an independent risk factor for high morbidity and mortality in hospitalized patients. This study was conducted to investigate the process of biofilm formation by C. tropicalis and the antifungal activity of liposomal amphotericin B (LAB) against both forming biofilms and developed biofilms using time-lapse imaging. We found that C. tropicalis has a high capacity for hyphal growth and gas generation due to its high metabolic activity. Thus, we visually observed the formation of aggressive C. tropicalis biofilms, which are fast-growing biofilms. We found that LAB acts immediately and completely inhibits forming biofilms. Furthermore, we demonstrated that LAB was effective against developed C. tropicalis biofilms by reducing the growth of hyphae and morphological changes. These results suggest that LAB may be effective for the treatment of infections caused by catheter-related C. tropicalis biofilms.}, } @article {pmid28674047, year = {2017}, author = {Moon, KH and Weber, BS and Feldman, MF}, title = {Subinhibitory Concentrations of Trimethoprim and Sulfamethoxazole Prevent Biofilm Formation by Acinetobacter baumannii through Inhibition of Csu Pilus Expression.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {9}, pages = {}, pmid = {28674047}, issn = {1098-6596}, support = {R01 AI125363/AI/NIAID NIH HHS/United States ; }, mesh = {Acinetobacter Infections/*drug therapy/metabolism ; Acinetobacter baumannii/*drug effects/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*metabolism ; Biofilms/*drug effects ; Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Sulfamethoxazole/*pharmacology ; Trimethoprim/*pharmacology ; Virulence Factors/metabolism ; }, abstract = {Acinetobacter baumannii is emerging as a multidrug-resistant nosocomial pathogen of increasing threat to human health worldwide. Pili are important bacterial virulence factors, playing a role in attachment to host cells and biofilm formation. The Csu pilus, which is assembled via the chaperone-usher secretion system, has been studied in A. baumannii ATCC 19606. Here we show that, in opposition to previous reports, the common laboratory strain ATCC 17978 produces Csu pili. We found that, although ATCC 17978 was resistant to sulfamethoxazole (Smx) and trimethoprim (Tmp), subinhibitory concentrations of these antibiotics abolished the expression of Csu and consequently produced a dramatic reduction in biofilm formation by ATCC 17978. Smx and Tmp acted synergistically to inhibit the enzymatic systems involved in the bacterial synthesis of tetrahydrofolate (THF), which is required for the synthesis of nucleotides. The effects of these antibiotics were partially relieved by exogenous THF addition, indicating that Smx and Tmp turn off Csu assembly by inducing folate stress. We propose that, for Acinetobacter, nanomolar concentrations of Smx and Tmp represent a "danger signal." In response to this signal, Csu expression is repressed, allowing biofilm dispersal and escape from potentially inhibitory concentrations of antibiotics. The roles of antibiotics as signaling molecules are being increasingly acknowledged, with clear implications for both the treatment of bacterial diseases and the understanding of complex microbial interactions in the environment.}, } @article {pmid28674029, year = {2017}, author = {Jung, CJ and Hsu, RB and Shun, CT and Hsu, CC and Chia, JS}, title = {AtlA Mediates Extracellular DNA Release, Which Contributes to Streptococcus mutans Biofilm Formation in an Experimental Rat Model of Infective Endocarditis.}, journal = {Infection and immunity}, volume = {85}, number = {9}, pages = {}, pmid = {28674029}, issn = {1098-5522}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; DNA, Bacterial/*metabolism ; DNA, Ribosomal/analysis ; Disease Models, Animal ; Endocarditis/*microbiology/*pathology ; Gene Deletion ; Heart Valves/microbiology/pathology ; Microscopy, Confocal ; N-Acetylmuramoyl-L-alanine Amidase/genetics/*metabolism ; RNA, Ribosomal, 16S/genetics ; Rats, Wistar ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/metabolism/*physiology ; Virulence Factors/genetics/metabolism ; }, abstract = {Host factors, such as platelets, have been shown to enhance biofilm formation by oral commensal streptococci, inducing infective endocarditis (IE), but how bacterial components contribute to biofilm formation in vivo is still not clear. We demonstrated previously that an isogenic mutant strain of Streptococcus mutans deficient in autolysin AtlA (ΔatlA) showed a reduced ability to cause vegetation in a rat model of bacterial endocarditis. However, the role of AtlA in bacterial biofilm formation is unclear. In this study, confocal laser scanning microscopy analysis showed that extracellular DNA (eDNA) was embedded in S. mutans GS5 floes during biofilm formation on damaged heart valves, but an ΔatlA strain could not form bacterial aggregates. Semiquantification of eDNA by PCR with bacterial 16S rRNA primers demonstrated that the ΔatlA mutant strain produced dramatically less eDNA than the wild type. Similar results were observed with in vitro biofilm models. The addition of polyanethol sulfonate, a chemical lysis inhibitor, revealed that eDNA release mediated by bacterial cell lysis is required for biofilm initiation and maturation in the wild-type strain. Supplementation of cultures with calcium ions reduced wild-type growth but increased eDNA release and biofilm mass. The effect of calcium ions on biofilm formation was abolished in ΔatlA cultures and by the addition of polyanethol sulfonate. The VicK sensor, but not CiaH, was found to be required for the induction of eDNA release or the stimulation of biofilm formation by calcium ions. These data suggest that calcium ion-regulated AtlA maturation mediates the release of eDNA by S. mutans, which contributes to biofilm formation in infective endocarditis.}, } @article {pmid28674000, year = {2017}, author = {DeFrancesco, AS and Masloboeva, N and Syed, AK and DeLoughery, A and Bradshaw, N and Li, GW and Gilmore, MS and Walker, S and Losick, R}, title = {Genome-wide screen for genes involved in eDNA release during biofilm formation by Staphylococcus aureus.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {29}, pages = {E5969-E5978}, pmid = {28674000}, issn = {1091-6490}, support = {P01 AI083214/AI/NIAID NIH HHS/United States ; R01 GM018568/GM/NIGMS NIH HHS/United States ; R37 GM018568/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Cell Wall/genetics/metabolism ; Congo Red/pharmacology ; DNA Transposable Elements ; DNA, Bacterial/*genetics ; Drug Resistance, Bacterial/drug effects/genetics ; Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Genome, Bacterial ; Genomics/methods ; Mutation ; Staphylococcus aureus/drug effects/pathogenicity/*physiology ; Virulence/genetics ; }, abstract = {Staphylococcus aureus is a leading cause of both nosocomial and community-acquired infection. Biofilm formation at the site of infection reduces antimicrobial susceptibility and can lead to chronic infection. During biofilm formation, a subset of cells liberate cytoplasmic proteins and DNA, which are repurposed to form the extracellular matrix that binds the remaining cells together in large clusters. Using a strain that forms robust biofilms in vitro during growth under glucose supplementation, we carried out a genome-wide screen for genes involved in the release of extracellular DNA (eDNA). A high-density transposon insertion library was grown under biofilm-inducing conditions, and the relative frequency of insertions was compared between genomic DNA (gDNA) collected from cells in the biofilm and eDNA from the matrix. Transposon insertions into genes encoding functions necessary for eDNA release were identified by reduced representation in the eDNA. On direct testing, mutants of some of these genes exhibited markedly reduced levels of eDNA and a concomitant reduction in cell clustering. Among the genes with robust mutant phenotypes were gdpP, which encodes a phosphodiesterase that degrades the second messenger cyclic-di-AMP, and xdrA, the gene for a transcription factor that, as revealed by RNA-sequencing analysis, influences the expression of multiple genes, including many involved in cell wall homeostasis. Finally, we report that growth in biofilm-inducing medium lowers cyclic-di-AMP levels and does so in a manner that depends on the gdpP phosphodiesterase gene.}, } @article {pmid28673990, year = {2017}, author = {}, title = {Correction for Rodesney et al., Mechanosensing of shear by Pseudomonas aeruginosa leads to increased levels of the cyclic-di-GMP signal initiating biofilm development.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {28}, pages = {E5760}, doi = {10.1073/pnas.1710411114}, pmid = {28673990}, issn = {1091-6490}, } @article {pmid28673928, year = {2017}, author = {Cromie, GA and Tan, Z and Hays, M and Sirr, A and Jeffery, EW and Dudley, AM}, title = {Transcriptional Profiling of Biofilm Regulators Identified by an Overexpression Screen in Saccharomyces cerevisiae.}, journal = {G3 (Bethesda, Md.)}, volume = {7}, number = {8}, pages = {2845-2854}, pmid = {28673928}, issn = {2160-1836}, support = {P50 GM076547/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Gene Deletion ; *Gene Expression Profiling ; Gene Expression Regulation, Fungal ; *Genetic Testing ; MAP Kinase Signaling System/genetics ; RNA, Messenger/genetics/metabolism ; RNA, Untranslated/genetics ; Saccharomyces cerevisiae/*genetics ; Transcription Factors/metabolism ; }, abstract = {Biofilm formation by microorganisms is a major cause of recurring infections and removal of biofilms has proven to be extremely difficult given their inherent drug resistance . Understanding the biological processes that underlie biofilm formation is thus extremely important and could lead to the development of more effective drug therapies, resulting in better infection outcomes. Using the yeast Saccharomyces cerevisiae as a biofilm model, overexpression screens identified DIG1, SFL1, HEK2, TOS8, SAN1, and ROF1/YHR177W as regulators of biofilm formation. Subsequent RNA-seq analysis of biofilm and nonbiofilm-forming strains revealed that all of the overexpression strains, other than DIG1 and TOS8, were adopting a single differential expression profile, although induced to varying degrees. TOS8 adopted a separate profile, while the expression profile of DIG1 reflected the common pattern seen in most of the strains, plus substantial DIG1-specific expression changes. We interpret the existence of the common transcriptional pattern seen across multiple, unrelated overexpression strains as reflecting a transcriptional state, that the yeast cell can access through regulatory signaling mechanisms, allowing an adaptive morphological change between biofilm-forming and nonbiofilm states.}, } @article {pmid28672877, year = {2017}, author = {Trøstrup, H and Lerche, CJ and Christophersen, L and Jensen, PØ and Høiby, N and Moser, C}, title = {Immune Modulating Topical S100A8/A9 Inhibits Growth of Pseudomonas aeruginosa and Mitigates Biofilm Infection in Chronic Wounds.}, journal = {International journal of molecular sciences}, volume = {18}, number = {7}, pages = {}, pmid = {28672877}, issn = {1422-0067}, mesh = {Administration, Topical ; Animals ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects ; Biomarkers ; Calgranulin A/*administration & dosage ; Calgranulin B/*administration & dosage ; Chronic Disease ; Cytokines/metabolism ; Host-Pathogen Interactions/immunology ; Immunologic Factors ; Inflammation Mediators/metabolism ; Leukocyte Count ; Mice ; Neutrophils/immunology/metabolism ; Pseudomonas Infections/drug therapy/*immunology/metabolism/*microbiology ; Pseudomonas aeruginosa/*immunology ; Wound Infection/drug therapy/*immunology/metabolism/*microbiology ; }, abstract = {Pseudomonas aeruginosa biofilm maintains and perturbs local host defense, hindering timely wound healing. Previously, we showed that P. aeruginosa suppressed S100A8/A9 of the murine innate host defense. We assessed the potential antimicrobial effect of S100A8/A9 on biofilm-infected wounds in a murine model and P. aeruginosa growth in vitro. Seventy-six mice, inflicted with a full-thickness burn wound were challenged subcutaneously (s.c.) by 10[6] colony-forming units (CFUs) of P. aeruginosa biofilm. Mice were subsequently randomized into two treatment groups, one group receiving recombinant murine S100A8/A9 and a group of vehicle controls (phosphate-buffered saline, PBS) all treated with s.c. injections daily for up to five days. Wounds were analyzed for quantitative bacteriology and contents of key inflammatory markers. Count of blood polymorphonuclear leukocytes was included. S100A8/A9-treatment ameliorated wound infection, as evaluated by quantitative bacteriology (p ≤ 0.05). In vitro, growth of P. aeruginosa was inhibited dose-dependently by S100A8/A9 in concentrations from 5 to 40 μg/mL, as determined by optical density-measurement (OD-measurement) and quantitative bacteriology. Treatment slightly augmented key inflammatory cytokine Tumor Necrosis Factor-α (TNF-α), but dampened interferon-γ (IFN-γ) levels and blood polymorphonuclear count. In conclusion, topical S100A8/A9 displays remarkable novel immune stimulatory and anti-infective properties in vivo and in vitro. Importantly, treatment by S100A8/A9 provides local infection control. Implications for a role as adjunctive treatment in healing of chronic biofilm-infected wounds are discussed.}, } @article {pmid28672861, year = {2017}, author = {Sans-Serramitjana, E and Jorba, M and Fusté, E and Pedraz, JL and Vinuesa, T and Viñas, M}, title = {Free and Nanoencapsulated Tobramycin: Effects on Planktonic and Biofilm Forms of Pseudomonas.}, journal = {Microorganisms}, volume = {5}, number = {3}, pages = {}, pmid = {28672861}, issn = {2076-2607}, abstract = {Cystic fibrosis (CF) is a genetic disorder in which frequent pulmonary infections develop secondarily. One of the major pulmonary pathogens colonizing the respiratory tract of CF patients and causing chronic airway infections is Pseudomonasaeruginosa. Although tobramycin was initially effective against P. aeruginosa, tobramycin-resistant strains have emerged. Among the strategies for overcoming resistance to tobramycin and other antibiotics is encapsulation of the drugs in nanoparticles. In this study, we explored the antimicrobial activity of nanoencapsulated tobramycin, both in solid lipid nanoparticles (SLN) and in nanostructured lipid carriers (NLC), against clinical isolates of P. aeruginosa obtained from CF patients. We also investigated the efficacy of these formulations in biofilm eradication. In both experiments, the activities of SLN and NLC were compared with that of free tobramycin. The susceptibility of planktonic bacteria was determined using the broth microdilution method and by plotting bacterial growth. The minimal biofilm eradication concentration (MBEC) was determined to assess the efficacy of the different tobramycin formulations against biofilms. The activity of tobramycin-loaded SLN was less than that of either tobramycin-loaded NLC or free tobramycin. The minimum inhibitory concentration (MIC) and MBEC of nanoencapsulated tobramycin were slightly lower (1-2 logs) than the corresponding values of the free drug when determined in tobramycin-susceptible isolates. However, in tobramycin-resistant strains, the MIC and MBEC did not differ between either encapsulated form and free tobramycin. Our results demonstrate the efficacy of nanoencapsulated formulations in killing susceptible P. aeruginosa from CF and from other patients.}, } @article {pmid28670301, year = {2017}, author = {Chhibber, S and Gondil, VS and Sharma, S and Kumar, M and Wangoo, N and Sharma, RK}, title = {A Novel Approach for Combating Klebsiella pneumoniae Biofilm Using Histidine Functionalized Silver Nanoparticles.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1104}, pmid = {28670301}, issn = {1664-302X}, abstract = {Treating pathogens is becoming challenging because of multidrug resistance and availability of limited alternative therapies which has further confounded this problem. The situation becomes more alarming when multidrug resistant pathogens form a 3D structure known as biofilm. Biofilms are formed in most of the infections especially in chronic infections where it is difficult to eradicate them by conventional antibiotic therapy. Chemically synthesized nanoparticles are known to have antibiofilm activity but in the present study, an attempt was made to use amino acid functionalized silver nanoparticles alone and in combination with gentamicin to eradicate Klebsiella pneumoniae biofilm. Amino acid functionalized silver nanoparticles were not only able to disrupt biofilm in vitro but also led to the lowering of gentamicin dose when used in combination. To the best of our knowledge, this is the first study demonstrating the application of amino acid functionalized silver nanoparticles in the eradication of young and old K. pneumoniae biofilm.}, } @article {pmid28670299, year = {2017}, author = {Liu, J and Fu, K and Wang, Y and Wu, C and Li, F and Shi, L and Ge, Y and Zhou, L}, title = {Detection of Diverse N-Acyl-Homoserine Lactones in Vibrio alginolyticus and Regulation of Biofilm Formation by N-(3-Oxodecanoyl) Homoserine Lactone In vitro.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1097}, pmid = {28670299}, issn = {1664-302X}, abstract = {Quorum sensing (QS) is a cell-to-cell communication system based on the exchange of small intercellular signal molecules, such as N-Acyl homoserine lactones (AHLs), which act as cell-density mediators of QS gene expression, and are highly variable both in types and amounts in most Gram-negative Proteobacteria. Understanding the regulation of AHLs may contribute to the elucidation of cell density-dependent phenomena, such as biofilm formation. Vibrio alginolyticus is among the most frequently observed marine opportunistic Vibrio pathogens. However, AHL production of this species and its effects on biofilm formation remain to be understood. Here, our study reported the diverse AHL profiles of 47 marine-isolated V. alginolyticus strains and the effects of exogenous 3-oxo-C10-HSL on biofilm formation under different temperature conditions (16°C and 28°C). A total of 11 detected AHLs were produced by the isolates, of which 3-OH-C4-HSL, 3-oxo-C10-HSL and 3-oxo-C14-HSL comprised the largest proportions. We also observed that moderate levels of exogenous 3-oxo-C10-HSL (10 and 20 μM) could induce or enhance biofilm formation and alter its structure, while high levels (40 and 100 μM) did not significantly improve and even inhibited biofilm formation in V. alginolyticus. Further, regulation by exogenous 3-oxo-C10-HSL was both concentration- and temperature-dependent in V. alginolyticus.}, } @article {pmid28670278, year = {2017}, author = {Wang, S and Wang, C and Gao, L and Cai, H and Zhou, Y and Yang, Y and Xu, C and Ding, W and Chen, J and Muhammad, I and Chen, X and He, X and Liu, D and Li, Y}, title = {Rutin Inhibits Streptococcus suis Biofilm Formation by Affecting CPS Biosynthesis.}, journal = {Frontiers in pharmacology}, volume = {8}, number = {}, pages = {379}, pmid = {28670278}, issn = {1663-9812}, abstract = {Streptococcus suis (S. suis) form biofilms and causes severe diseases in humans and pigs. Biofilms are communities of microbes embedded in a matrix of extracellular polymeric substances. Eradicating biofilms with the use of antibiotics or biocides is often ineffective and needs replacement with other potential agents. Compared to conventional agents, promising and potential alternatives are biofilm-inhibiting compounds without impairing growth. Here, we screened a S. suis adhesion inhibitor, rutin, derived from Syringa. Rutin, a kind of flavonoids, shows efficient biofilm inhibition of S. suis without impairing its growth. Capsular polysaccharides(CPS) are reported to be involved in its adherence to influence bacterial biofilm formation. We investigated the effect of rutin on S. suis CPS content and structure. The results showed that rutin was beneficial to improve the CPS content of S. suis without changing its structure. We further provided evidence that rutin specifically affected S. suis biofilm susceptibility by affecting CPS biosynthesis in vitro. The study explores the antibiofilm potential of rutin against S. suis which can be used as an adhesion inhibitor for the prevention of S. suis biofilm-related infections. Nevertheless, rutin could be used as a novel natural inhibitor of biolfilm and its molecular mechanism provide basis for its pharmacological and clinical applications.}, } @article {pmid28668766, year = {2017}, author = {Huang, X and Zhang, K and Deng, M and Exterkate, RAM and Liu, C and Zhou, X and Cheng, L and Ten Cate, JM}, title = {Effect of arginine on the growth and biofilm formation of oral bacteria.}, journal = {Archives of oral biology}, volume = {82}, number = {}, pages = {256-262}, doi = {10.1016/j.archoralbio.2017.06.026}, pmid = {28668766}, issn = {1879-1506}, mesh = {Arginine/*pharmacology ; Biofilms/*drug effects/*growth & development ; Dental Caries/microbiology ; Humans ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Saliva/*microbiology ; Stem Cells ; Streptococcus gordonii/drug effects ; Streptococcus mutans/*drug effects ; Streptococcus sanguis/drug effects ; Streptococcus sobrinus/drug effects ; }, abstract = {BACKGROUND: Alkali production via arginine deiminase system (ADS) of oral bacteria plays a significant role in oral ecology, pH homeostasis and inhibition of dental caries. ADS activity in dental plaque varies greatly between individuals, which may profoundly affect their susceptibility to caries.

OBJECTIVE: To investigate the effect of arginine on the growth and biofilm formation of oral bacteria.

METHODS AND RESULTS: Polymicrobial dental biofilms derived from saliva were formed in a high-throughput active attachment biofilm model and l-arginine (Arg) was shown to reduce the colony forming units (CFU) counts of such biofilms grown for various periods or biofilms derived from saliva of subjects with different caries status. Arg hardly disturbed bacterial growth of Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis and Streptococcus gordonii in BHI medium, but only inhibited biofilm formation of S. mutans. Scanning electron microscope (SEM) showed S. mutans biofilms harboured fewer cells grown with Arg than that without Arg, even in the initial 2h and 8h phase. Confocal laser scanning microscope (CLSM) images of poly-microbial dental and S. mutans biofilms revealed the biofilms grown with Arg had lower exopolysaccharide (EPS)/bacteria ratios than those without Arg (P=0.004, 0.002, respectively). Arg could significantly reduce the production of water-insoluble EPS in S. mutans biofilms (P<0.001); however, quantitative real-time PCR (qRT-PCR) did not show significantly influence in gene expression of gtfB, gtfC or gtfD (P=0.32, 0.06, 0.44 respectively).

CONCLUSIONS: Arg could reduce the biomass of poly-microbial dental biofilms and S. mutans biofilms, which may be due to the impact of Arg on water-insoluble EPS. Considering the contribution to pH homeostasis in dental biofilms, Arg may serve as an important agent keeping oral biofilms healthy thus prevent dental caries.}, } @article {pmid28667872, year = {2017}, author = {Gill, RK and Kumar, V and Robijns, SCA and Steenackers, HPL and Van der Eycken, EV and Bariwal, J}, title = {Polysubstituted 2-aminoimidazoles as anti-biofilm and antiproliferative agents: Discovery of potent lead.}, journal = {European journal of medicinal chemistry}, volume = {138}, number = {}, pages = {152-169}, doi = {10.1016/j.ejmech.2017.06.043}, pmid = {28667872}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antineoplastic Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Dose-Response Relationship, Drug ; *Drug Discovery ; Drug Screening Assays, Antitumor ; Humans ; Imidazoles/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas aeruginosa/drug effects/metabolism ; Salmonella typhimurium/drug effects/metabolism ; Staphylococcus aureus/drug effects/metabolism ; Structure-Activity Relationship ; }, abstract = {Most of the human bacterial infections are associated with the biofilm formation and the natural tolerance of biofilms to antibiotics challenges treatment. Because of their low immunity, cancer patients are especially susceptible to bacterial infections. Compounds with anti-biofilm activity could therefore become a useful adjunct to chemotherapy, in particular if they also show antiproliferative activities. Taking this into consideration and as a result of our continuous interest in 2-aminoimidazole derivatives, we have designed and synthesized a series of novel polysubstituted 2-aminoimidazoles (20a-x). The compounds were evaluated against a panel of three bacterial strains for their biofilm and planktonic growth inhibitory activity and most of them show promising results. Furthermore, the synthesized compounds were evaluated against various cancer cell lines and almost all the compounds were found to possess potent antiproliferative activity. The substitution pattern at the C-4 position and the aryl carboxamide ring at the N-1 position have major effects on the biofilm inhibitory and antiproliferative activity. Especially, the introduction of a p-methyl group at the carboxamide ring remarkably enhances both the anti-biofilm and antiproliferative activity. The two most potent compounds (20i &20r) were further studied for their antiproliferative activity and a flow cytometer-based cell cycle experiment was performed, which revealed their capability to induce G2/M phase cell cycle arrest. Based on these results, these two new compounds having potential to target both cancer proliferation and microbial biofilms might be used in single drug monotherapy.}, } @article {pmid28667350, year = {2017}, author = {Mahdinia, E and Demirci, A and Berenjian, A}, title = {Strain and plastic composite support (PCS) selection for vitamin K (Menaquinone-7) production in biofilm reactors.}, journal = {Bioprocess and biosystems engineering}, volume = {40}, number = {10}, pages = {1507-1517}, doi = {10.1007/s00449-017-1807-x}, pmid = {28667350}, issn = {1615-7605}, mesh = {Bacillus/*physiology ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Vitamin K 2/*analogs & derivatives/metabolism ; }, abstract = {Menaquinone-7 (MK-7), a subtype of vitamin K, has received a significant attention due to its effect on improving bone and cardiovascular health. Current fermentation strategies, which involve static fermentation without aeration or agitation, are associated with low productivity and scale-up issues and hardly justify the commercial production needs of this vitamin. Previous studies indicate that static fermentation is associated with pellicle and biofilm formations, which are critical for MK-7 secretion while posing significant operational issues. Therefore, the present study is undertaken to evaluate the possibility of using a biofilm reactor as a new strategy for MK-7 fermentation. Bacillus species, namely, Bacillus subtilis natto, Bacillus licheniformis, and Bacillus amyloliquifaciens as well as plastic composite, supports (PCS) were investigated in terms of MK-7 production and biofilm formation. Results show the possibility of using a biofilm reactor for MK-7 biosynthesis. Bacillus subtilis natto and soybean flour yeast extract PCS in glucose medium were found as the most potent combination for production of MK-7 as high as 35.5 mg/L, which includes both intracellular and extracellular MK-7.}, } @article {pmid28666415, year = {2017}, author = {de Carvalho Dias, K and Barbugli, PA and de Patto, F and Lordello, VB and de Aquino Penteado, L and Medeiros, AI and Vergani, CE}, title = {Soluble factors from biofilm of Candida albicans and Staphylococcus aureus promote cell death and inflammatory response.}, journal = {BMC microbiology}, volume = {17}, number = {1}, pages = {146}, pmid = {28666415}, issn = {1471-2180}, mesh = {Bacterial Proteins/*pharmacology ; Biofilms/growth & development ; Candida albicans/*metabolism/physiology ; Cell Survival/drug effects ; Cells, Cultured ; Humans ; Interleukin-6/metabolism ; Keratinocytes/cytology/*drug effects/immunology/metabolism ; Macrophages/cytology/*drug effects/immunology/metabolism ; Nitric Oxide/metabolism ; Staphylococcus aureus/*metabolism/physiology ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {BACKGROUND: The objective of this study was to better understand the effects of soluble factors from biofilm of single- and mixed-species Candida albicans (C. albicans) and methicillin-sensitive Staphylococcus aureus (MSSA) cultures after 36 h in culture on keratinocytes (NOK-si and HaCaT) and macrophages (J774A.1). Soluble factors from biofilms of C. albicans and MSSA were collected and incubated with keratinocytes and macrophages, which were subsequently evaluated by cell viability assays (MTT). Lactate dehydrogenase (LDH) enzyme release was measured to assess cell membrane damage to keratinocytes. Cells were analysed by brightfield microscopy after 2 and 24 h of exposure to the soluble factors from biofilm. Cell death was detected by labelling apoptotic cells with annexin V and necrotic cells with propidium iodide (PI) and was visualized via fluorescence microscopy. Soluble factors from biofilm were incubated with J774A.1 cells for 24 h; the subsequent production of NO and the cytokines IL-6 and TNF-α was measured by ELISA.

RESULTS: The cell viability assays showed that the soluble factors of single-species C. albicans cultures were as toxic as the soluble factors from biofilm of mixed cultures, whereas the soluble factors of MSSA cultures were less toxic than those of C. albicans or mixed cultures. The soluble factors from biofilm of mixed cultures were the most toxic to the NOK-si and HaCaT cells, as confirmed by analyses of PI labelling and cell morphology. Soluble factors from biofilm of single-species MSSA and mixed-species cultures induced the production of IL-6, NO and TNF-α by J744A.1 macrophages. The production of IL-6 and NO induced by the soluble factors from biofilm of mixed cultures was lower than that induced by the soluble factors from biofilm of single-species MSSA cultures, whereas the soluble factors from biofilm of C. albicans cultures induced only low levels of NO.

CONCLUSIONS: Soluble factors from 36-h-old biofilm of C. albicans and MSSA cultures promoted cell death and inflammatory responses.}, } @article {pmid28666212, year = {2017}, author = {Shirato, M and Nakamura, K and Kanno, T and Lingström, P and Niwano, Y and Örtengren, U}, title = {Time-kill kinetic analysis of antimicrobial chemotherapy based on hydrogen peroxide photolysis against Streptococcus mutans biofilm.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {173}, number = {}, pages = {434-440}, doi = {10.1016/j.jphotobiol.2017.06.023}, pmid = {28666212}, issn = {1873-2682}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/radiation effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Durapatite/chemistry ; Hydrogen Peroxide/*pharmacology ; Kinetics ; Light ; Microscopy, Confocal ; Photolysis/drug effects/radiation effects ; Povidone-Iodine/pharmacology ; Streptococcus mutans/*physiology ; Time Factors ; }, abstract = {A recently developed antimicrobial technique utilizing hydroxyl radicals generated by hydrogen peroxide (H2O2) photolysis represents a promising new therapy for preventing and treating dental caries. The present study compared the antimicrobial time-kill kinetics of H2O2 photolysis, conventional antiseptics, and antimicrobial photodynamic therapy (aPDT) against biofilm-forming Streptococcus mutans (cariogenic bacteria) grown on hydroxyapatite disks. H2O2 photolysis was performed by irradiating the biofilm immersed in 3% H2O2 with 365-nm light-emitting diode (LED) light at an irradiance of 1000mW/cm[2] for up to 1.5min. Antiseptic treatments consisted of 0.2% chlorhexidine gluconate, 0.5% povidone-iodine, and 3% H2O2. The biofilm was immersed in each antiseptic for up to 4min. aPDT was performed by irradiating the biofilm immersed in 100μM methylene blue or toluidine blue O with 655-nm laser light at 1000mW/cm[2] for up to 4min. Based on the time-kill assay, the decimal reduction value (D-value) of each treatment was determined. With a D-value of 0.06min, H2O2 photolysis exhibited the highest bactericidal effect against biofilm-forming S. mutans. In contrast, antiseptics and aPDT exerted a slower bactericidal effect, with D-values of 0.9-2.7min. In conclusion, the antimicrobial technique based on H2O2 photolysis using 365-nm LED represents a strong adjunctive chemotherapy for dental caries treatment.}, } @article {pmid28662943, year = {2017}, author = {Aung, TT and Chor, WHJ and Yam, JKH and Givskov, M and Yang, L and Beuerman, RW}, title = {Discovery of novel antimycobacterial drug therapy in biofilm of pathogenic nontuberculous mycobacterial keratitis.}, journal = {The ocular surface}, volume = {15}, number = {4}, pages = {770-783}, doi = {10.1016/j.jtos.2017.06.002}, pmid = {28662943}, issn = {1937-5913}, mesh = {Animals ; *Biofilms ; Keratitis ; Mice ; Mycobacterium Infections, Nontuberculous ; Mycobacterium chelonae ; Mycobacterium fortuitum ; }, abstract = {PURPOSE: The potential of slow-growing mycobacteria to form biofilms in human tissues contributes to the problem of establishing an effective treatment strategy. The purpose of this study was to examine new antibiotic strategies to enhance current treatment options for these infections.

METHODS: Sensitivities of Mycobacterium fortuitum ATCC 49404 and Mycobacterium chelonae ATCC 35752 were evaluated for different antimicrobials singly and in combination using broth microdilution and FICI (Fractional Inhibitory Concentration Index) synergy screening. Anti-biofilm effects were evaluated in an 8-well chamber slide biofilm model. The efficacy of a new treatment strategy was validated using the novel neutropenic mouse keratitis model and monitored by slit-lamp microscopy, confocal microscopy, and colony forming unit measurements.

RESULTS: We reported the very first evidence that these organisms develop corneal biofilms by the accumulation of extracellular DNA (eDNA) and the presence of microcolonies using a novel mycobacterial neutropenic mouse keratitis model. The combination of amikacin and gatifloxacin or besifloxacin was more effective than the current gold-standard drug, amikacin, and we developed a novel treatment strategy (amikacin + gatifloxacin + DNase), the destruction of biofilm matrix component, eDNA, which increased the efficacy of the new antibiotic combination for treating mycobacterial infection in in vitro (P = 0.002) and in vivo (P = 0.001) compared to its respective control.

CONCLUSION: Biofilms have a role in mycobacterial keratitis leading to poor treatment outcomes in clinical practice and the use of combination therapy (amikacin + gatifloxacin + DNase) could be a useful new treatment option.}, } @article {pmid28662376, year = {2017}, author = {Mugita, N and Nambu, T and Takahashi, K and Wang, PL and Komasa, Y}, title = {Proteases, actinidin, papain and trypsin reduce oral biofilm on the tongue in elderly subjects and in vitro.}, journal = {Archives of oral biology}, volume = {82}, number = {}, pages = {233-240}, doi = {10.1016/j.archoralbio.2017.04.035}, pmid = {28662376}, issn = {1879-1506}, mesh = {Actinomyces/*drug effects ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biofilms/*drug effects ; Cross-Over Studies ; Cysteine Endopeptidases/*pharmacology ; Double-Blind Method ; Female ; Humans ; Male ; Middle Aged ; Papain/*pharmacology ; Peptide Hydrolases/*pharmacology ; Tongue/*microbiology ; Trypsin/*pharmacology ; }, abstract = {OBJECTIVE: Dental plaque is a causative factor for oral disease and a potential reservoir for respiratory infection in the elderly. Therefore, there is a critical need for the development of effective methods to remove oral biofilm. The objective of this study was to investigate the effect of proteases on oral biofilm formation andremoval.

DESIGN: The in vivo effect of actinidin, a cysteine protease, on the removal of tongue coating was assessed after orally taking a protease tablet. Effects of the proteases trypsin, papain and actinidin on Actinomyces monospecies biofilm and multispecies biofilm that was reconstructed using a plaque sample from the tongue coating were investigated using the microtiter plate method. Antimicrobial tests and limited proteolysis of fimbrial shaft proteins were also performed to clarify underlying mechanisms of oral biofilm removal.

RESULTS: Tablets containing actinidin removed tongue coating in elderly subjects. Oral Actinomyces biofilm was significantly reduced by the proteases papain, actinidin and trypsin. Papain and trypsin effectively digested the major fimbrial proteins, FimP and FimA, from Actinomyces. Actinidin, papain and trypsin reduced multispecies biofilm that was reconstructed in vitro. Papain and trypsin inhibited formation of multispecies biofilm in vitro.

CONCLUSIONS: This study shows that proteases reduced oral biofilm in vivo in elderly subjects and in vitro, and suggests that protease digests fimbriae and inhibits biofilm formation.}, } @article {pmid28659908, year = {2017}, author = {Yang, SC and Tseng, CH and Wang, PW and Lu, PL and Weng, YH and Yen, FL and Fang, JY}, title = {Pterostilbene, a Methoxylated Resveratrol Derivative, Efficiently Eradicates Planktonic, Biofilm, and Intracellular MRSA by Topical Application.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1103}, pmid = {28659908}, issn = {1664-302X}, abstract = {Pterostilbene is a methoxylated derivative of resveratrol originated from natural sources. We investigated the antibacterial activity of pterostilbene against drug-resistant Staphylococcus aureus and the feasibility of using it to treat cutaneous bacteria. The antimicrobial effect was evaluated using an in vitro culture model and an in vivo mouse model of cutaneous infection. The minimum inhibitory concentration (MIC) assay demonstrated a superior biocidal activity of pterostilbene compared to resveratrol (8~16-fold) against methicillin-resistant S. aureus (MRSA) and clinically isolated vancomycin-intermediate S. aureus (VISA). Pterostilbene was found to reduce MRSA biofilm thickness from 18 to 10 μm as detected by confocal microscopy. Pterostilbene showed minimal toxicity to THP-1 cells and was readily engulfed by the macrophages, facilitating the eradication of intracellular MRSA. Pterostilbene exhibited increased skin absorption over resveratrol by 6-fold. Topical pterostilbene application improved the abscess formation produced by MRSA by reducing the bacterial burden and ameliorating the skin architecture. The potent anti-MRSA capability of pterostilbene was related to bacterial membrane leakage, chaperone protein downregulation, and ribosomal protein upregulation. This mechanism of action was different from that of resveratrol according to proteomic analysis and molecular docking. Pterostilbene has the potential to serve as a novel class of topically applied agents for treating MRSA infection in the skin while demonstrating less toxicity to mammalian cells.}, } @article {pmid28659894, year = {2017}, author = {Singh, A and Gupta, R and Tandon, S and Pandey, R}, title = {Thyme Oil Reduces Biofilm Formation and Impairs Virulence of Xanthomonas oryzae.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1074}, pmid = {28659894}, issn = {1664-302X}, abstract = {Xanthomonas oryzae pv. oryzae (Xoo), a common bacterial plant pathogen regulates its virulence and biofilm formation attribute via a chemical method of communication. Disabling this mechanism offers a promising alternative to reduce the virulence and pathogencity of the microorganism. In this study, the effect of thyme (THY) oil on Quorum Sensing mediated synthesis of various virulence factors and biofilm formation was analyzed. Treatment of Xoo with 500 ppm THY oil displayed a significant diminution in swimming, swarming, exopolysaccharide and xanthomonadin secretion. However, no effect was observed on bacterial growth kinetics and metabolic activity of the cells. Results were further authenticated by RT-qPCR as significant reduction in motA, motB, and flgE genes was observed upon THY oil treatment. Similarly, the expression of some extracellular enzyme genes such as endoglucanase, xylanase, cellobiosidase, and polygalacturonase was also found to be significantly reduced. However, biochemical plate assays revealed insignificant effect of 500 ppm THY oil on secretion of protease, cellulase, and lipase enzymes. The rpfF gene known to play a crucial role in the virulence of the phytopathogenic bacteria was also significantly reduced in the THY oil treated Xoo cells. HPTLC analysis further revealed significant reduction in DSF and BDSF signaling molecules when Xoo cells were treated with 500 ppm THY oil. Disease reduction was observed in in vitro agar plate assay as lesion length was reduced in THY oil treated Xoo cells when compared with the alone treatment. GC-MS result revealed thymol as the active and major component of THY oil which showed potential binding with rpfF gene. Application of 75 μM thymol resulted in downregulation of gumC, motA, estA, virulence acvB and pglA along with rpfF. The other genes such as cheD, flgA, cheY, and pilA, were not found to be significantly affected. Overall, the results clearly indicated THY oil and its active component Thymol to be a potential candidate for the development of anti-virulence agent which in future when applied in combination with conventional bactericides might not only help in lowering the dose of bactericides but also be successful in curbing the disease progression in rice.}, } @article {pmid28659875, year = {2017}, author = {Lindemann, SR and Mobberley, JM and Cole, JK and Markillie, LM and Taylor, RC and Huang, E and Chrisler, WB and Wiley, HS and Lipton, MS and Nelson, WC and Fredrickson, JK and Romine, MF}, title = {Predicting Species-Resolved Macronutrient Acquisition during Succession in a Model Phototrophic Biofilm Using an Integrated 'Omics Approach.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1020}, pmid = {28659875}, issn = {1664-302X}, abstract = {The principles governing acquisition and interspecies exchange of nutrients in microbial communities and how those exchanges impact community productivity are poorly understood. Here, we examine energy and macronutrient acquisition in unicyanobacterial consortia for which species-resolved genome information exists for all members, allowing us to use multi-omic approaches to predict species' abilities to acquire resources and examine expression of resource-acquisition genes during succession. Metabolic reconstruction indicated that a majority of heterotrophic community members lacked the genes required to directly acquire the inorganic nutrients provided in culture medium, suggesting high metabolic interdependency. The sole primary producer in consortium UCC-O, cyanobacterium Phormidium sp. OSCR, displayed declining expression of energy harvest, carbon fixation, and nitrate and sulfate reduction proteins but sharply increasing phosphate transporter expression over 28 days. Most heterotrophic members likewise exhibited signs of phosphorus starvation during succession. Though similar in their responses to phosphorus limitation, heterotrophs displayed species-specific expression of nitrogen acquisition genes. These results suggest niche partitioning around nitrogen sources may structure the community when organisms directly compete for limited phosphate. Such niche complementarity around nitrogen sources may increase community diversity and productivity in phosphate-limited phototrophic communities.}, } @article {pmid28659522, year = {2017}, author = {Boltz, JP and Johnson, BR and Takács, I and Daigger, GT and Morgenroth, E and Brockmann, D and Kovács, R and Calhoun, JM and Choubert, JM and Derlon, N}, title = {Biofilm carrier migration model describes reactor performance.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {75}, number = {12}, pages = {2818-2828}, doi = {10.2166/wst.2017.160}, pmid = {28659522}, issn = {0273-1223}, mesh = {*Biofilms ; *Bioreactors ; Hydrodynamics ; Waste Disposal, Fluid/*methods ; }, abstract = {The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, Xcarrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of Xcarrier and associated biofilms, and evaluates the impact that Xcarrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.}, } @article {pmid28658633, year = {2017}, author = {Matar, GK and Bagchi, S and Zhang, K and Oerther, DB and Saikaly, PE}, title = {Membrane biofilm communities in full-scale membrane bioreactors are not randomly assembled and consist of a core microbiome.}, journal = {Water research}, volume = {123}, number = {}, pages = {124-133}, doi = {10.1016/j.watres.2017.06.052}, pmid = {28658633}, issn = {1879-2448}, mesh = {*Biofilms ; *Bioreactors ; Microbiota ; RNA, Ribosomal, 16S ; Washington ; *Waste Disposal, Fluid ; }, abstract = {Finding efficient biofouling control strategies requires a better understanding of the microbial ecology of membrane biofilm communities in membrane bioreactors (MBRs). Studies that characterized the membrane biofilm communities in lab-and pilot-scale MBRs are numerous, yet similar studies in full-scale MBRs are limited. Also, most of these studies have characterized the mature biofilm communities with very few studies addressing early biofilm communities. In this study, five full-scale MBRs located in Seattle (Washington, U.S.A.) were selected to address two questions concerning membrane biofilm communities (early and mature): (i) Is the assembly of biofilm communities (early and mature) the result of random immigration of species from the source community (i.e. activated sludge)? and (ii) Is there a core membrane biofilm community in full-scale MBRs? Membrane biofilm (early and mature) and activated sludge (AS) samples were collected from the five MBRs, and 16S rRNA gene sequencing was applied to investigate the bacterial communities of AS and membrane biofilms (early and mature). Alpha and beta diversity measures revealed clear differences in the bacterial community structure between the AS and biofilm (early and mature) samples in the five full-scale MBRs. These differences were mainly due to the presence of large number of unique but rare operational taxonomic units (∼13% of total reads in each MBR) in each sample. In contrast, a high percentage (∼87% of total reads in each MBR) of sequence reads was shared between AS and biofilm samples in each MBR, and these shared sequence reads mainly belong to the dominant taxa in these samples. Despite the large fraction of shared sequence reads between AS and biofilm samples, simulated biofilm communities from random sampling of the respective AS community revealed that biofilm communities differed significantly from the random assemblages (P < 0.001 for each MBR), indicating that the biofilm communities (early and mature) are unlikely to represent a random sample of the AS community. In addition to the presence of unique operational taxonomic units in each biofilm sample (early or mature), comparative analysis of operational taxonomic units and genera revealed the presence of a core biofilm community in the five full-scale MBRs. These findings provided insight into the membrane biofilm communities in full-scale MBRs. More comparative studies are needed in the future to elucidate the factors shaping the core and unique biofilm communities in full-scale MBRs.}, } @article {pmid28658258, year = {2017}, author = {Borlee, GI and Plumley, BA and Martin, KH and Somprasong, N and Mangalea, MR and Islam, MN and Burtnick, MN and Brett, PJ and Steinmetz, I and AuCoin, DP and Belisle, JT and Crick, DC and Schweizer, HP and Borlee, BR}, title = {Genome-scale analysis of the genes that contribute to Burkholderia pseudomallei biofilm formation identifies a crucial exopolysaccharide biosynthesis gene cluster.}, journal = {PLoS neglected tropical diseases}, volume = {11}, number = {6}, pages = {e0005689}, pmid = {28658258}, issn = {1935-2735}, support = {R01 AI049151/AI/NIAID NIH HHS/United States ; R42 AI102482/AI/NIAID NIH HHS/United States ; R56 AI049151/AI/NIAID NIH HHS/United States ; U54 AI065357/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Burkholderia cenocepacia/genetics ; Burkholderia pseudomallei/*genetics/*physiology ; Comparative Genomic Hybridization ; Gene Expression Regulation, Bacterial ; *Genome, Bacterial ; Multigene Family ; Mutation ; Polysaccharides, Bacterial/*genetics ; }, abstract = {Burkholderia pseudomallei, the causative agent of melioidosis, is an important public health threat due to limited therapeutic options for treatment. Efforts to improve therapeutics for B. pseudomallei infections are dependent on the need to understand the role of B. pseudomallei biofilm formation and its contribution to antibiotic tolerance and persistence as these are bacterial traits that prevent effective therapy. In order to reveal the genes that regulate and/or contribute to B. pseudomallei 1026b biofilm formation, we screened a sequence defined two-allele transposon library and identified 118 transposon insertion mutants that were deficient in biofilm formation. These mutants include transposon insertions in genes predicted to encode flagella, fimbriae, transcriptional regulators, polysaccharides, and hypothetical proteins. Polysaccharides are key constituents of biofilms and B. pseudomallei has the capacity to produce a diversity of polysaccharides, thus there is a critical need to link these biosynthetic genes with the polysaccharides they produce to better understand their biological role during infection. An allelic exchange deletion mutant of the entire B. pseudomallei biofilm-associated exopolysaccharide biosynthetic cluster was decreased in biofilm formation and produced a smooth colony morphology suggestive of the loss of exopolysaccharide production. Conversely, deletion of the previously defined capsule I polysaccharide biosynthesis gene cluster increased biofilm formation. Bioinformatics analyses combined with immunoblot analysis and glycosyl composition studies of the partially purified exopolysaccharide indicate that the biofilm-associated exopolysaccharide is neither cepacian nor the previously described acidic exopolysaccharide. The biofilm-associated exopolysaccharide described here is also specific to the B. pseudomallei complex of bacteria. Since this novel exopolysaccharide biosynthesis cluster is retained in B. mallei, it is predicted to have a role in colonization and infection of the host. These findings will facilitate further advances in understanding the pathogenesis of B. pseudomallei and improve diagnostics and therapeutic treatment strategies.}, } @article {pmid28656173, year = {2017}, author = {Mishra, S and Horswill, AR}, title = {Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting Staphylococcus aureus Biofilm Formation.}, journal = {mSphere}, volume = {2}, number = {3}, pages = {}, pmid = {28656173}, issn = {2379-5042}, support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; }, abstract = {Staphylococcus aureus is a leading cause of catheter-related bloodstream infections. Biofilms form on these implants and are held together by a matrix composed of proteins, polysaccharides, and extracellular DNA (eDNA). Heparin is a sulfated glycosaminoglycan that is routinely used in central venous catheters to prevent thrombosis, but it has been shown to stimulate S. aureus biofilm formation through an unknown mechanism. Data presented here reveal that heparin enhances biofilm capacity in many S. aureus and coagulase-negative staphylococcal strains, and it is incorporated into the USA300 methicillin-resistant S. aureus (MRSA) biofilm matrix. The S. aureus USA300 biofilms containing heparin are sensitive to proteinase K treatment, which suggests that proteins have an important structural role during heparin incorporation. Multiple heparin-binding proteins were identified by proteomics of the secreted and cell wall fractions. Proteins known to contribute to biofilm were identified, and some proteins were reported to have the ability to bind eDNA, such as the major autolysin (Atl) and the immunodominant surface protein B (IsaB). Mutants defective in IsaB showed a moderate decrease in biofilm capacity in the presence of heparin. Our findings suggested that heparin is substituting for eDNA during S. aureus biofilm development. To test this model, eDNA content was increased in biofilms through inactivation of nuclease activity, and the heparin enhancement effect was attenuated. Collectively, these data support the hypothesis that S. aureus can incorporate heparin into the matrix and enhance biofilm capacity by taking advantage of existing eDNA-binding proteins. IMPORTANCEStaphylococcus aureus and coagulase-negative staphylococci (CoNS) are the leading causes of catheter implant infections. Identifying the factors that stimulate catheter infection and the mechanism involved is important for preventing such infections. Heparin, the main component of catheter lock solutions, has been shown previously to stimulate S. aureus biofilm formation through an unknown pathway. This work identifies multiple heparin-binding proteins in S. aureus, and it reveals a potential mechanism through which heparin enhances biofilm capacity. Understanding the details of the heparin enhancement effect could guide future use of appropriate lock solutions for catheter implants.}, } @article {pmid28656080, year = {2017}, author = {Ghadam, P and Akhlaghi, F and Ali, AA}, title = {One-step purification and characterization of alginate lyase from a clinical Pseudomonas aeruginosa with destructive activity on bacterial biofilm.}, journal = {Iranian journal of basic medical sciences}, volume = {20}, number = {5}, pages = {467-473}, pmid = {28656080}, issn = {2008-3866}, abstract = {OBJECTIVES: Pseudomonas aeruginosa is a Gram-negative and aerobic rod bacterium that displays mucoid and non-mucoid phenotype. Mucoid strains secrete alginate, which is the main agent of biofilms in chronic P. aeruginosa infections, show high resistance to antibiotics; consequently, the biological disruption of mucoid P. aeruginosa biofilms is an attractive area of study for researchers. Alginate lyase gene (algl) is a member of alginate producing operon which by glycosidase activity produces primer for other enzymes in this cluster. Also this activity can destroy the extracellular alginate; therefore this enzyme participates in alginate production and destruction pathway. Alginate lyase causes detachment of a biofilm by reducing its adhesion to the surfaces, and increases phagocytosis and antibiotic susceptibility. In this study, alginate lyase was purified in just one step and its properties were investigated.

MATERIALS AND METHODS: The purification was done by affinity chromatography, analysed by SDS-PAGE, and its effect on P. aeruginosa biofilms was surveyed by micro titer plate assay and SEM. The substrate specificity of the enzyme was determined by PCR.

RESULTS: Alginate lyase from isolate 48 was purified in one step. It is more thermally resistant than alginate lyase from Pseudomonas aeruginosa PAO1 and poly M, poly G and poly MG alginate were the substrate of this enzyme. Moreover, it has an eradication effect on biofilms from P. aeruginosa 48 and PAO1.

CONCLUSION: In this study an alginate lyase with many characteristics suitable in medicine such as thermal stability, effective on poly M alginate, and bacterial biofilm destructive was introduced and purified.}, } @article {pmid28655056, year = {2017}, author = {Argyraki, A and Markvart, M and Bjørndal, L and Bjarnsholt, T and Petersen, PM}, title = {Inactivation of Pseudomonas aeruginosa biofilm after ultraviolet light-emitting diode treatment: a comparative study between ultraviolet C and ultraviolet B.}, journal = {Journal of biomedical optics}, volume = {22}, number = {6}, pages = {65004}, doi = {10.1117/1.JBO.22.6.065004}, pmid = {28655056}, issn = {1560-2281}, mesh = {Biofilms/*radiation effects ; Disinfection/*methods ; Microbial Viability/*radiation effects ; Pseudomonas aeruginosa/*radiation effects ; Reproducibility of Results ; *Ultraviolet Rays ; }, abstract = {The objective of this study was to test the inactivation efficiency of two different light-based treatments, namely ultraviolet B (UVB) and ultraviolet C (UVC) irradiation, on Pseudomonas aeruginosa biofilms at different growth stages (24, 48, and 72 h grown). In our experiments, a type of AlGaN light-emitting diodes (LEDs) was used to deliver UV irradiation on the biofilms. The effectiveness of the UVB at 296 nm and UVC at 266 nm irradiations was quantified by counting colony-forming units. The survival of less mature biofilms (24 h grown) was studied as a function of UV-radiant exposure. All treatments were performed on three different biological replicates to test reproducibility. It was shown that UVB irradiation was significantly more effective than UVC irradiation in inactivating P. aeruginosa biofilms. UVC irradiation induced insignificant inactivation on mature biofilms. The fact that the UVB at 296 nm exists in daylight and has such disinfection ability on biofilms provides perspectives for the treatment of infectious diseases.}, } @article {pmid28654375, year = {2017}, author = {Bardes, JM and Gray, D and Wilson, A}, title = {Re: Effect of the endOclear[®] Device on Biofilm in Endotracheal Tubes.}, journal = {Surgical infections}, volume = {18}, number = {5}, pages = {643-644}, doi = {10.1089/sur.2017.067}, pmid = {28654375}, issn = {1557-8674}, mesh = {Biofilms/*drug effects ; *Intubation, Intratracheal ; }, } @article {pmid28654117, year = {2017}, author = {Nizalapur, S and Kimyon, O and Yee, E and Bhadbhade, MM and Manefield, M and Willcox, M and Black, DS and Kumar, N}, title = {Synthesis and biological evaluation of novel acyclic and cyclic glyoxamide based derivatives as bacterial quorum sensing and biofilm inhibitors.}, journal = {Organic & biomolecular chemistry}, volume = {15}, number = {27}, pages = {5743-5755}, doi = {10.1039/c7ob01011g}, pmid = {28654117}, issn = {1477-0539}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Crystallography, X-Ray ; Dose-Response Relationship, Drug ; Escherichia coli/*drug effects ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Structure ; Pseudomonas aeruginosa/*drug effects ; Quorum Sensing/*drug effects ; Structure-Activity Relationship ; Sulfonylurea Compounds/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Bacteria regulate the expression of various virulence factors and processes such as biofilm formation through a chemically-mediated communication mechanism called quorum sensing. Bacterial biofilms contribute to antimicrobial resistance as they can protect bacteria embedded in their matrix from the effects of antibiotics. Thus, developing novel quorum sensing inhibitors, which can inhibit biofilm formation, is a viable strategy to combat antimicrobial resistance. We report herein the synthesis of novel acyclic and cyclic glyoxamide derivatives via ring-opening reactions of N-acylisatins. These compounds were evaluated for their quorum sensing inhibition activity against P. aeruginosa MH602 and E. coli MT102. Compounds 20, 21 and 30 displayed the greatest quorum sensing inhibition activity against P. aeruginosa MH602, with 71.5%, 71.5%, and 74% inhibition, respectively, at 250 μM. Compounds 18, 20 and 21 exhibited the greatest QSI activity against E. coli MT102, with 71.5%, 72.1% and 73.5% quorum sensing inhibition activity, respectively. In addition, the biofilm inhibition activity was also investigated against P. aeruginosa and E. coli at 250 μM. The glyoxamide compounds 16, 18 and 19 exhibited 71.2%, 66.9%, and 66.5% inhibition of P. aeruginosa biofilms, respectively; whereas compounds 12, 20, and 22 showed the greatest inhibitory activity against E. coli biofilms with 87.9%, 90.8% and 89.5%, respectively. Finally, the determination of the in vitro toxicity against human MRC-5 lung fibroblast cells revealed that these novel glyoxamide compounds are non-toxic to human cells.}, } @article {pmid28652741, year = {2017}, author = {Sans-Serramitjana, E and Jorba, M and Pedraz, JL and Vinuesa, T and Viñas, M}, title = {Determination of the spatiotemporal dependence of Pseudomonas aeruginosa biofilm viability after treatment with NLC-colistin.}, journal = {International journal of nanomedicine}, volume = {12}, number = {}, pages = {4409-4413}, pmid = {28652741}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry/*pharmacology ; Biofilms/drug effects ; Colistin/administration & dosage/chemistry/*pharmacology ; Cystic Fibrosis/microbiology ; Drug Carriers/administration & dosage/chemistry/*pharmacology ; Humans ; Lipids/administration & dosage/chemistry ; Microbial Sensitivity Tests ; Nanostructures ; Pseudomonas aeruginosa/*drug effects ; Spatio-Temporal Analysis ; }, abstract = {The emergence of colistin-resistant Pseudomonas aeruginosa in cystic fibrosis (CF) patients, particularly after long-term inhalation treatments, has been recently reported. Nanoen-capsulation may enable preparations to overcome the limitations of conventional pharmaceutical forms. We have determined the time-dependent viability of P. aeruginosa biofilms treated with both free and nanoencapsulated colistin. We also examined the relationship between the optimal anti-biofilm activity of nanostructured lipid carrier (NLC)-colistin and the structural organization of the biofilm itself. The results showed the more rapid killing of P. aeruginosa bacterial biofilms by NLC-colistin than by free colistin. However, the two formulations did not differ in terms of the final percentages of living and dead cells, which were higher in the inner than in the outer layers of the treated biofilms. The effective anti-biofilm activity of NLC-colistin and its faster killing effect recommend further studies of its use over free colistin in the treatment of P. aeruginosa infections in CF patients.}, } @article {pmid28652311, year = {2017}, author = {Purcell, EB and McKee, RW and Courson, DS and Garrett, EM and McBride, SM and Cheney, RE and Tamayo, R}, title = {A Nutrient-Regulated Cyclic Diguanylate Phosphodiesterase Controls Clostridium difficile Biofilm and Toxin Production during Stationary Phase.}, journal = {Infection and immunity}, volume = {85}, number = {9}, pages = {}, pmid = {28652311}, issn = {1098-5522}, support = {P30 ES010126/ES/NIEHS NIH HHS/United States ; R01 AI107029/AI/NIAID NIH HHS/United States ; T32 CA009156/CA/NCI NIH HHS/United States ; R01 DC003299/DC/NIDCD NIH HHS/United States ; K01 DK087763/DK/NIDDK NIH HHS/United States ; T32 DK007737/DK/NIDDK NIH HHS/United States ; U54 AI057157/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Toxins/*metabolism ; Biofilms/*growth & development ; Clostridioides difficile/*enzymology/metabolism/*physiology ; Cyclic GMP/*analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Gene Knockout Techniques ; Locomotion ; Phosphoric Diester Hydrolases/genetics/*metabolism ; }, abstract = {The signaling molecule cyclic diguanylate (c-di-GMP) mediates physiological adaptation to extracellular stimuli in a wide range of bacteria. The complex metabolic pathways governing c-di-GMP synthesis and degradation are highly regulated, but the specific cues that impact c-di-GMP signaling are largely unknown. In the intestinal pathogen Clostridium difficile, c-di-GMP inhibits flagellar motility and toxin production and promotes pilus-dependent biofilm formation, but no specific biological functions have been ascribed to any of the individual c-di-GMP synthases or phosphodiesterases (PDEs). Here, we report the functional and biochemical characterization of a c-di-GMP PDE, PdcA, 1 of 37 confirmed or putative c-di-GMP metabolism proteins in C. difficile 630. Our studies reveal that pdcA transcription is controlled by the nutrient-regulated transcriptional regulator CodY and accordingly increases during stationary phase. In addition, PdcA PDE activity is allosterically regulated by GTP, further linking c-di-GMP levels to nutrient availability. Mutation of pdcA increased biofilm formation and reduced toxin biosynthesis without affecting swimming motility or global intracellular c-di-GMP. Analysis of the transcriptional response to pdcA mutation indicates that PdcA-dependent phenotypes manifest during stationary phase, consistent with regulation by CodY. These results demonstrate that inactivation of this single PDE gene is sufficient to impact multiple c-di-GMP-dependent phenotypes, including the production of major virulence factors, and suggest a link between c-di-GMP signaling and nutrient availability.}, } @article {pmid28652301, year = {2017}, author = {El Mouali, Y and Kim, H and Ahmad, I and Brauner, A and Liu, Y and Skurnik, M and Galperin, MY and Römling, U}, title = {Stand-Alone EAL Domain Proteins Form a Distinct Subclass of EAL Proteins Involved in Regulation of Cell Motility and Biofilm Formation in Enterobacteria.}, journal = {Journal of bacteriology}, volume = {199}, number = {18}, pages = {}, pmid = {28652301}, issn = {1098-5530}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cluster Analysis ; Computational Biology ; Conserved Sequence ; Cyclic GMP/*analogs & derivatives/metabolism ; Enterobacteriaceae/*genetics/*physiology ; *Gene Expression Regulation, Bacterial ; *Locomotion ; Phosphoric Diester Hydrolases/genetics/*metabolism ; Phylogeny ; Sequence Homology, Amino Acid ; }, abstract = {The second messenger cyclic dimeric GMP (c-di-GMP) is almost ubiquitous among bacteria as are the c-di-GMP turnover proteins, which mediate the transition between motility and sessility. EAL domain proteins have been characterized as c-di-GMP-specific phosphodiesterases. While most EAL domain proteins contain additional, usually N-terminal, domains, there is a distinct family of proteins with stand-alone EAL domains, exemplified by Salmonella enterica serovar Typhimurium proteins STM3611 (YhjH/PdeH), a c-di-GMP-specific phosphodiesterase, and the enzymatically inactive STM1344 (YdiV/CdgR) and STM1697, which regulate bacterial motility through interaction with the flagellar master regulator, FlhDC. We have analyzed the phylogenetic distribution of EAL-only proteins and their potential functions. Genes encoding EAL-only proteins were found in various bacterial phyla, although most of them were seen in proteobacteria, particularly enterobacteria. Based on the conservation of the active site residues, nearly all stand-alone EAL domains encoded by genomes from phyla other than proteobacteria appear to represent functional phosphodiesterases. Within enterobacteria, EAL-only proteins were found to cluster either with YhjH or with one of the subfamilies of YdiV-related proteins. EAL-only proteins from Shigella flexneri, Klebsiella pneumoniae, and Yersinia enterocolitica were tested for their ability to regulate swimming and swarming motility and formation of the red, dry, and rough (rdar) biofilm morphotype. In these tests, YhjH-related proteins S4210, KPN_01159, KPN_03274, and YE4063 displayed properties typical of enzymatically active phosphodiesterases, whereas S1641 and YE1324 behaved like members of the YdiV/STM1697 subfamily, with Yersinia enterocolitica protein YE1324 shown to downregulate motility in its native host. Of two closely related EAL-only proteins, YE2225 is an active phosphodiesterase, while YE1324 appears to interact with FlhD. These results suggest that in FlhDC-harboring beta- and gammaproteobacteria, some EAL-only proteins evolved to become catalytically inactive and regulate motility and biofilm formation by interacting with FlhDC.IMPORTANCE The EAL domain superfamily consists mainly of proteins with cyclic dimeric GMP-specific phosphodiesterase activity, but individual domains have been classified in three classes according to their functions and conserved amino acid signatures. Proteins that consist solely of stand-alone EAL domains cannot rely on other domains to form catalytically active dimers, and most of them fall into one of two distinct classes: catalytically active phosphodiesterases with well-conserved residues of the active site and the dimerization loop, and catalytically inactive YdiV/CdgR-like proteins that regulate bacterial motility by binding to the flagellar master regulator, FlhDC, and are found primarily in enterobacteria. The presence of apparently inactive EAL-only proteins in the bacteria that do not express FlhD suggests the existence of additional EAL interaction partners.}, } @article {pmid28650789, year = {2017}, author = {Dotsey, RP and Moser, EAS and Eckert, GJ and Gregory, RL}, title = {Effects of Cola-Flavored Beverages and Caffeine on Streptococcus mutans Biofilm Formation and Metabolic Activity.}, journal = {The Journal of clinical pediatric dentistry}, volume = {41}, number = {4}, pages = {294-299}, doi = {10.17796/1053-4628-41.4.294}, pmid = {28650789}, issn = {1053-4628}, mesh = {Biofilms/*growth & development ; Caffeine/*pharmacology ; Carbonated Beverages/*adverse effects ; Cariogenic Agents/*adverse effects ; Cola/*adverse effects ; Dose-Response Relationship, Drug ; High Fructose Corn Syrup/*pharmacology ; Humans ; Oxidation-Reduction/drug effects ; Streptococcus mutans/*growth & development/*metabolism ; }, abstract = {OBJECTIVE: To examine the effects of cola-flavored beverages and caffeine on growth and metabolism of Streptococcus mutans biofilm. This study was designed to determine if carbonated beverages or caffeine can increase S. mutans growth and biofilm formation and metabolic activity in vitro, potentially leading to increased S. mutans-associated cariogenicity in children that consume them.

STUDY DESIGN: Six different cola-flavored products, plus pure caffeine, and pure high fructose corn syrup (HFCS), at different concentrations similar to those in the beverages were tested. A 16-hour culture of S. mutans was treated with different dilutions in bacteriological media. To test for the effect on biofilm formation, the biofilm was stained with crystal violet. The absorbance was determined to evaluate biofilm growth. Biofilm metabolic activity was measured based on biofilm having the ability to reduce XTT to a water-soluble orange compound.

RESULTS: The inclusion of HFCS in the beverages, as well as pure HFCS, significantly enhanced bacterial biofilm formation and metabolic activity. Pure caffeine and the presence of caffeine in beverages did not significantly increase biofilm formation, but pure caffeine significantly increased metabolism, and Diet Coke had significantly greater metabolic activity than Caffeine-Free Diet Coke.

CONCLUSIONS: HFCS increases both the biofilm formation and metabolism of S. mutans, and caffeine in some cases increases metabolism of S. mutans.}, } @article {pmid28650325, year = {2017}, author = {Karbasizade, V and Dehghan, P and Sichani, MM and Shahanipoor, K and Jafari, R and Yousefian, R}, title = {Evaluation of three plant extracts against biofilm formation and expression of quorum sensing regulated virulence factors in Pseudomonas aeruginosa.}, journal = {Pakistan journal of pharmaceutical sciences}, volume = {30}, number = {2(Suppl.)}, pages = {585-589}, pmid = {28650325}, issn = {1011-601X}, mesh = {Biofilms/*drug effects ; Carum/chemistry ; Lamiaceae/chemistry ; Microbial Sensitivity Tests ; Pancreatic Elastase/metabolism ; Peptide Hydrolases/metabolism ; Plant Extracts/chemistry/*pharmacology ; Plants, Medicinal/chemistry ; Pseudomonas aeruginosa/*drug effects/*metabolism ; Pyocyanine/metabolism ; Quercus/chemistry ; Quorum Sensing/drug effects/*physiology ; Virulence Factors/*metabolism ; }, abstract = {Following the increasing antibiotic resistance of pathogenic bacteria, the use of medicinal herbs as antibacterial agents has attracted growing attention. Pseudomonas aeruginosa is a human opportunistic pathogen that uses quorum sensing for regulating virulence gene expression (pyocyanin, protease, and elastase production and biofilm formation). This study examined the anti-quorum sensing activity of Quercus infectoria, Zataria multiflora and Trachyspermum copticum extracts on standard P. aeruginosa strain. The minimum inhibitory concentration (MIC) of Q. infectoria, Z. multiflora and T. copticum extracts for standard P. aeruginosa strain was determined through micro dilution. Microtiter plates were used to evaluate the anti-quorum sensing effects of the three extracts (at a sub-MIC concentration) on pyocyanin, protease, and elastase production and biofilm formation. The acetone extract of Q. infectoria showed the highest anti-quorum sensing activity and reduced the pyocyanin, protease, and elastase production and biofilm formation by 89.1%, 78%, 73.3%, and 70.1%, respectively. The corresponding values were 88.2%, 72.1%, 69%, and 61.1% for the methanol extract of Z. multiflora and 70.6%, 63.42%, 60.1%, and 59.1% for the methanol extract of T. copticum. Considering the high anti-quorum sensing activity of the studied extracts, especially the acetone extract of Q. infectoria, these herbs can be used as antipathogenic drugs.}, } @article {pmid28649410, year = {2017}, author = {Chung, EMC and Dean, SN and Propst, CN and Bishop, BM and van Hoek, ML}, title = {Komodo dragon-inspired synthetic peptide DRGN-1 promotes wound-healing of a mixed-biofilm infected wound.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {9}, pmid = {28649410}, issn = {2055-5008}, abstract = {Cationic antimicrobial peptides are multifunctional molecules that have a high potential as therapeutic agents. We have identified a histone H1-derived peptide from the Komodo dragon (Varanus komodoensis), called VK25. Using this peptide as inspiration, we designed a synthetic peptide called DRGN-1. We evaluated the antimicrobial and anti-biofilm activity of both peptides against Pseudomonas aeruginosa and Staphylococcus aureus. DRGN-1, more than VK25, exhibited potent antimicrobial and anti-biofilm activity, and permeabilized bacterial membranes. Wound healing was significantly enhanced by DRGN-1 in both uninfected and mixed biofilm (Pseudomonas aeruginosa and Staphylococcus aureus)-infected murine wounds. In a scratch wound closure assay used to elucidate the wound healing mechanism, the peptide promoted the migration of HEKa keratinocyte cells, which was inhibited by mitomycin C (proliferation inhibitor) and AG1478 (epidermal growth factor receptor inhibitor). DRGN-1 also activated the EGFR-STAT1/3 pathway. Thus, DRGN-1 is a candidate for use as a topical wound treatment. Wound infections are a major concern; made increasingly complicated by the emerging, rapid spread of bacterial resistance. The novel synthetic peptide DRGN-1 (inspired by a peptide identified from Komodo dragon) exhibits pathogen-directed and host-directed activities in promoting the clearance and healing of polymicrobial (Pseudomonas aeruginosa & Staphylococcus aureus) biofilm infected wounds. The effectiveness of this peptide cannot be attributed solely to its ability to act upon the bacteria and disrupt the biofilm, but also reflects the peptide's ability to promsote keratinocyte migration. When applied in a murine model, infected wounds treated with DRGN-1 healed significantly faster than did untreated wounds, or wounds treated with other peptides. The host-directed mechanism of action was determined to be via the EGFR-STAT1/3 pathway. The pathogen-directed mechanism of action was determined to be via anti-biofilm activity and antibacterial activity through membrane permeabilization. This novel peptide may have potential as a future therapeutic for treating infected wounds.}, } @article {pmid28649408, year = {2017}, author = {Arora, G and Sajid, A and Virmani, R and Singhal, A and Kumar, CMS and Dhasmana, N and Khanna, T and Maji, A and Misra, R and Molle, V and Becher, D and Gerth, U and Mande, SC and Singh, Y}, title = {Ser/Thr protein kinase PrkC-mediated regulation of GroEL is critical for biofilm formation in Bacillus anthracis.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {7}, pmid = {28649408}, issn = {2055-5008}, abstract = {PrkC is a conserved Ser/Thr protein kinase encoded in Bacillus anthracis genome. PrkC is shown to be important for B. anthracis pathogenesis, but little is known about its other functions and phosphorylated substrates. Systemic analyses indicate the compelling role of PrkC in phosphorylating multiple substrates, including the essential chaperone GroEL. Through mass spectrometry, we identified that PrkC phosphorylates GroEL on six threonine residues that are distributed in three canonical regions. Phosphorylation facilitates the oligomerization of GroEL to the physiologically active tetradecameric state and increases its affinity toward the co-chaperone GroES. Deletion of prkC in B. anthracis abrogates its ability to form biofilm. Overexpression of native GroEL recovers the biofilm-forming ability of prkC deletion strain. Similar overexpression of GroEL phosphorylation site mutants (Thr to Ala) does not augment biofilm formation. Further analyses indicate the phosphorylation of GroEL in diverse bacterial species. Thus, our results suggest that PrkC regulates biofilm formation by modulating the GroEL activity in a phosphorylation-dependent manner. The study deciphers the molecular signaling events that are important for biofilm formation in B. anthracis.}, } @article {pmid28649407, year = {2017}, author = {Jang, H and Rusconi, R and Stocker, R}, title = {Biofilm disruption by an air bubble reveals heterogeneous age-dependent detachment patterns dictated by initial extracellular matrix distribution.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {6}, pmid = {28649407}, issn = {2055-5008}, abstract = {Bacteria often adhere to surfaces, where they form communities known as biofilms. Recently, it has been shown that biofilm formation initiates with the microscopically heterogeneous deposition of a skeleton of extracellular polymeric substances (EPS) by individual cells crawling on the surface, followed by growth of the biofilm into a surface-covering continuum. Here we report microfluidic experiments with Pseudomonas aeruginosa biofilms showing that their "hidden" heterogeneity can affect the later dynamics of their disruption. Using controlled air bubbles as a model for mechanical insult, we demonstrate that biofilm disruption is strongly dependent on biofilm age, and that disruption to early-stage biofilms can take the shape of a semi-regular pattern of ~15 µm diameter holes from which bacteria have been removed. We explain hole formation in terms of the rupture and retreat of the thin liquid layer created by the long bubble, which scrapes bacteria off the surface and rearranges their distribution. We find that the resulting pattern correlates with the spatial distribution of EPS: holes form where there is less EPS, whereas regions with more EPS act as strongholds against the scraping liquid front. These results show that heterogeneity in the microscale EPS skeleton of biofilms has profound consequences for later dynamics, including disruption. Because few attached cells suffice to regrow a biofilm, these results point to the importance of considering microscale heterogeneity when designing and assessing the effectiveness of biofilm removal strategies by mechanical forces.}, } @article {pmid28649406, year = {2017}, author = {Inaba, T and Hori, T and Aizawa, H and Ogata, A and Habe, H}, title = {Architecture, component, and microbiome of biofilm involved in the fouling of membrane bioreactors.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {5}, pmid = {28649406}, issn = {2055-5008}, abstract = {Biofilm formation on the filtration membrane and the subsequent clogging of membrane pores (called biofouling) is one of the most persistent problems in membrane bioreactors for wastewater treatment and reclamation. Here, we investigated the structure and microbiome of fouling-related biofilms in the membrane bioreactor using non-destructive confocal reflection microscopy and high-throughput Illumina sequencing of 16S rRNA genes. Direct confocal reflection microscopy indicated that the thin biofilms were formed and maintained regardless of the increasing transmembrane pressure, which is a common indicator of membrane fouling, at low organic-loading rates. Their solid components were primarily extracellular polysaccharides and microbial cells. In contrast, high organic-loading rates resulted in a rapid increase in the transmembrane pressure and the development of the thick biofilms mainly composed of extracellular lipids. High-throughput sequencing revealed that the biofilm microbiomes, including major and minor microorganisms, substantially changed in response to the organic-loading rates and biofilm development. These results demonstrated for the first time that the architectures, chemical components, and microbiomes of the biofilms on fouled membranes were tightly associated with one another and differed considerably depending on the organic-loading conditions in the membrane bioreactor, emphasizing the significance of alternative indicators other than the transmembrane pressure for membrane biofouling.}, } @article {pmid28649405, year = {2017}, author = {Ma, W and Peng, D and Walker, SL and Cao, B and Gao, CH and Huang, Q and Cai, P}, title = {Bacillus subtilis biofilm development in the presence of soil clay minerals and iron oxides.}, journal = {NPJ biofilms and microbiomes}, volume = {3}, number = {}, pages = {4}, pmid = {28649405}, issn = {2055-5008}, abstract = {Clay minerals and metal oxides, as important parts of the soil matrix, play crucial roles in the development of microbial communities. However, the mechanism underlying such a process, particularly on the formation of soil biofilm, remains poorly understood. Here, we investigated the effects of montmorillonite, kaolinite, and goethite on the biofilm formation of the representative soil bacteria Bacillus subtilis. The bacterial biofilm formation in goethite was found to be impaired in the initial 24 h but burst at 48 h in the liquid-air interface. Confocal laser scanning microscopy showed that the biofilm biomass in goethite was 3-16 times that of the control, montmorillonite, and kaolinite at 48 h. Live/Dead staining showed that cells had the highest death rate of 60% after 4 h of contact with goethite, followed by kaolinite and montmorillonite. Atomic force microscopy showed that the interaction between goethite and bacteria may injure bacterial cells by puncturing cell wall, leading to the swarming of bacteria toward the liquid-air interface. Additionally, the expressions of abrB and sinR, key players in regulating the biofilm formation, were upregulated at 24 h and downregulated at 48 h in goethite, indicating the initial adaptation of the cells to minerals. A model was proposed to describe the effects of goethite on the biofilm formation. Our findings may facilitate a better understanding of the roles of soil clays in biofilm development and the manipulation of bacterial compositions through controlling the biofilm in soils.}, } @article {pmid28649399, year = {2016}, author = {Cao, H and Habimana, O and Safari, A and Heffernan, R and Dai, Y and Casey, E}, title = {Revealing region-specific biofilm viscoelastic properties by means of a micro-rheological approach.}, journal = {NPJ biofilms and microbiomes}, volume = {2}, number = {}, pages = {5}, pmid = {28649399}, issn = {2055-5008}, abstract = {Particle-tracking microrheology is an in situ technique that allows quantification of biofilm material properties. It overcomes the limitations of alternative techniques such as bulk rheology or force spectroscopy by providing data on region specific material properties at any required biofilm location and can be combined with confocal microscopy and associated structural analysis. This article describes single particle tracking microrheology combined with confocal laser scanning microscopy to resolve the biofilm structure in 3 dimensions and calculate the creep compliances locally. Samples were analysed from Pseudomonas fluorescens biofilms that were cultivated over two timescales (24 h and 48 h) and alternate ionic conditions (with and without calcium chloride supplementation). The region-based creep compliance analysis showed that the creep compliance of biofilm void zones is the primary contributor to biofilm mechanical properties, contributing to the overall viscoelastic character.}, } @article {pmid28647798, year = {2017}, author = {Glage, S and Paret, S and Winkel, A and Stiesch, M and Bleich, A and Krauss, JK and Schwabe, K}, title = {A new model for biofilm formation and inflammatory tissue reaction: intraoperative infection of a cranial implant with Staphylococcus aureus in rats.}, journal = {Acta neurochirurgica}, volume = {159}, number = {9}, pages = {1747-1756}, doi = {10.1007/s00701-017-3244-7}, pmid = {28647798}, issn = {0942-0940}, support = {VWZN2860//Ministry of Lower Saxony and the VolkswagenStiftung/International ; }, mesh = {Animals ; *Biofilms ; Disease Models, Animal ; Fibrosis ; Inflammation ; Postoperative Complications/*microbiology/pathology ; Prostheses and Implants/adverse effects/*microbiology ; Rats ; Rats, Sprague-Dawley ; Skull/pathology/surgery ; Staphylococcal Infections/etiology/*microbiology ; Staphylococcus aureus/pathogenicity/physiology ; Titanium ; }, abstract = {BACKGROUND: Implant failure is a severe and frequent adverse event in all areas of neurosurgery. It often involves infection with biofilm formation, accompanied by inflammation of surrounding tissue, including the brain, and bone loss. The most common bacteria involved are Staphylococcus aureus. We here test whether intraoperative infection of intracranial screws with Staphylococcus aureus would lead to biofilm formation and inflammatory tissue reaction in rats.

METHODS: Two titanium screws were implanted in the cranium of Sprague-Dawley rats, anesthetized with xylazine (4 mg/kg) and ketamine (75 mg/kg). Prior to the implantation of the screws, Staphylococcus aureus was given in the drill holes; controls received phosphate-buffered saline (PBS). Rats were euthanized 2, 10 and 21 days after surgery to remove the screws for analysis of biofilm formation with a confocal laser scanning microscope. The surrounding tissue composed of soft tissue and bone, as well as the underlying brain tissue, was evaluated for inflammation, bone remodeling, foreign body reaction and fibrosis after H&E staining.

RESULTS: Intraoperative application of Staphylococcus aureus leads to robust and stable biofilm formation on the titanium implants on days 10 and 21 after surgery, while no bacteria were found in controls. This was accompanied by a substantial inflammatory response of peri-implant tissue after infection, also affecting the underlying brain tissue.

CONCLUSIONS: Intraoperative infection of implants with Staphylococcus aureus in rats may be useful as a tool to model new implant materials and surfaces on biofilm formation and inflammatory tissue reaction in vivo.}, } @article {pmid28647124, year = {2017}, author = {Bandekar, D and Chouhan, OP and Mohapatra, S and Hazra, M and Hazra, S and Biswas, S}, title = {Putative protein VC0395_0300 from Vibrio cholerae is a diguanylate cyclase with a role in biofilm formation.}, journal = {Microbiological research}, volume = {202}, number = {}, pages = {61-70}, doi = {10.1016/j.micres.2017.05.003}, pmid = {28647124}, issn = {1618-0623}, mesh = {Bacterial Proteins/chemistry/genetics/physiology ; Base Sequence ; Biofilms/*growth & development ; Cellulose/metabolism ; Cloning, Molecular ; Cyclic GMP/analogs & derivatives/metabolism ; DNA, Bacterial ; Enzyme Assays ; Escherichia coli/genetics ; Escherichia coli Proteins/chemistry/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Genome, Bacterial ; Guanosine Triphosphate/metabolism ; Locomotion ; Microscopy, Electron, Scanning ; Models, Molecular ; Molecular Structure ; Phosphorus-Oxygen Lyases/chemistry/genetics/*physiology ; Recombinant Proteins ; Sequence Homology ; Vibrio cholerae/*enzymology/genetics/metabolism ; }, abstract = {The hallmark of the lifecycle of Vibrio cholerae is its ability to switch between two lifestyles - the sessile, non-pathogenic form and the motile, infectious form in human hosts. One of these changes is in the formation of surface biofilms, when in sessile aquatic habitats. The cell-cell interactions within a V. cholerae biofilm are stabilized by the production of an exopolysachharide (EPS) matrix, which in turn is regulated by the ubiquitous secondary messenger, cyclic di-GMP (c-di-GMP), synthesized by proteins containing GGD(/E)EF domains in all prokaryotic systems. Here, we report the functional role of the VC0395_0300 protein (Sebox3) encoded by the chromosome I of V. cholerae, with a GGEEF signature sequence, in the formation of surface biofilms. In our study, we have shown that Escherichia coli containing the full-length Sebox3 displays enhanced biofilm forming ability with cellulose production as quantified and visualized by multiple assays, most notably using FEG-SEM. This has also been corroborated with the lack of motility of host containing Sebox3 in semi-solid media. Searching for the reasons for this biofilm formation, we have demonstrated in vitro that Sebox3 can synthesize c-di-GMP from GTP. The homology derived model of Sebox3 displayed significant conservation of the GGD(/E)EF architecture as well. Hence, we propose that the putative protein VC0395_0300 from V. cholerae is a diguanylate cyclase which has an active role in biofilm formation.}, } @article {pmid28645160, year = {2017}, author = {Trøstrup, H and Lerche, CJ and Christophersen, LJ and Thomsen, K and Jensen, PØ and Hougen, HP and Høiby, N and Moser, C}, title = {Chronic Pseudomonas aeruginosa biofilm infection impairs murine S100A8/A9 and neutrophil effector cytokines-implications for delayed wound closure?.}, journal = {Pathogens and disease}, volume = {75}, number = {7}, pages = {}, doi = {10.1093/femspd/ftx068}, pmid = {28645160}, issn = {2049-632X}, mesh = {Animals ; Biofilms/*growth & development ; Burns, Electric/immunology/*microbiology/pathology ; Calgranulin A/genetics/*immunology ; Calgranulin B/genetics/*immunology ; Disease Models, Animal ; Female ; Gene Expression Regulation ; Granulocyte Colony-Stimulating Factor/genetics/immunology ; Host-Pathogen Interactions ; Interleukin-1beta/genetics/immunology ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C3H ; Neutrophils/immunology/microbiology ; Pseudomonas Infections/immunology/*microbiology/pathology ; Pseudomonas aeruginosa/*pathogenicity/physiology ; Species Specificity ; Wound Healing/immunology ; Wound Infection/immunology/*microbiology/pathology ; }, abstract = {The impact of Pseudomonas aeruginosa biofilm infections in chronic wounds and clinical implication for healing is receiving increased attention. However, the pathophysiology of host/pathogen interplay is not fully understood. By further revealing the mechanisms, necessary new treatment strategies may be identified. Since the background for chronic wounds is diverse, representative animal models are important. We assessed host response and spontaneous wound closure in the relatively resistant C3H/HeN and the susceptible BALB/c mouse strain. Full-thickness burn wounds were inflicted in 108 mice. Pseudomonas aeruginosa biofilm (106 colony forming units) was injected subcutaneously in 72 mice, euthanised day 4, 7 or 10 days post-infection. Wounds were analysed for neutrophil host response markers: S100A8/A9, keratinocyte-derived chemokine and granulocyte-colony stimulating factor. Total peripheral blood leucocyte and polymorphonuclear count were assessed in parallel. Histopathology evaluated wound inflammatory burden. Photoplanimetry described macroscopical wound closure. Stable chronic wound infection was established in all challenged mice. Pseudomonas aeruginosa biofilm suppressed neutrophil host response in wounds. C3H/HeN mice achieved earlier systemic inflammatory control and healed faster than BALB/c mice. Pseudomonas aeruginosa biofilms perturb host defence thereby inducing a steady state of chronic infection which may impair wound healing. These results indicate therapeutic options for immune modulation of biofilm-infected wounds.}, } @article {pmid28644912, year = {2017}, author = {Pang, XY and Yang, YS and Yuk, HG}, title = {Biofilm formation and disinfectant resistance of Salmonella sp. in mono- and dual-species with Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {123}, number = {3}, pages = {651-660}, doi = {10.1111/jam.13521}, pmid = {28644912}, issn = {1365-2672}, mesh = {Biofilms/*drug effects ; Chlorine/*pharmacology ; Disinfectants/*pharmacology ; Disinfection ; Pseudomonas aeruginosa/*drug effects/physiology ; Salmonella/*drug effects/physiology ; Stainless Steel ; }, abstract = {AIMS: This study aimed to evaluate the biofilm formation and disinfectant resistance of Salmonella cells in mono- and dual-species biofilms with Pseudomonas aeruginosa, and to investigate the role of extracellular polymeric substances (EPS) in the protection of biofilms against disinfection treatment.

METHODS AND RESULTS: The populations of Salmonella in mono- or dual-species biofilms with P. aeruginosa on stainless steel (SS) coupons were determined before and after exposure to commercial disinfectant, 50 μg ml[-1] chlorine or 200 μg ml[-1] Ecolab[®] Whisper™ V (a blend of four effective quaternary ammonium compounds (QAC)). In addition, EPS amount from biofilms was quantified and biofilm structures were observed using scanning electron microscopy (SEM). Antagonistic interactions between Salmonella and P. aeruginosa resulted in lower planktonic population level of Salmonella, and lower density in dual-species biofilms compared to mono-species biofilms. The presence of P. aeruginosa significantly enhanced disinfectant resistance of S. Typhimurium and S. Enteritidis biofilm cells for 2 days, and led to an average of 50% increase in polysaccharides amount in dual-species biofilms than mono-species biofilms of Salmonella. Microscopy observation showed the presence of large microcolonies covered by EPS in dual-species biofilms but not in mono-species ones.

CONCLUSION: The presence of P. aeruginosa in dual-species culture inhibited the growth of Salmonella cells in planktonic phase and in biofilms, but protected Salmonella cells in biofilms from disinfection treatment, by providing more production of EPS in dual-species biofilms than mono-species ones.

This study provides insights into inter-species interaction, with regard to biofilm population dynamics and disinfectant resistance. Thus, a sanitation protocol should be designed considering the protective role of secondary species to pathogens in biofilms on SS surface which has been widely used at food surfaces and manufacturers.}, } @article {pmid28643413, year = {2017}, author = {Pumirat, P and Vanaporn, M and Boonyuen, U and Indrawattana, N and Rungruengkitkun, A and Chantratita, N}, title = {Effects of sodium chloride on heat resistance, oxidative susceptibility, motility, biofilm and plaque formation of Burkholderia pseudomallei.}, journal = {MicrobiologyOpen}, volume = {6}, number = {4}, pages = {}, pmid = {28643413}, issn = {2045-8827}, support = {U01 AI115520/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Burkholderia pseudomallei/*drug effects/growth & development/*physiology/radiation effects ; Culture Media/chemistry ; Flagella/drug effects ; Hot Temperature ; Hydrogen Peroxide/toxicity ; Locomotion/*drug effects ; Microbial Viability/drug effects ; Organelle Biogenesis ; Sodium Chloride/*metabolism ; Stress, Physiological/*drug effects ; }, abstract = {Burkholderia pseudomallei is an environmental saprophyte and the causative agent of melioidosis, a severe infectious disease prevalent in tropical areas, including southeast Asia and northern Australia. In Thailand, the highest incidence of melioidosis is in the northeast region, where saline soil and water are abundant. We hypothesized that B. pseudomallei develops an ability to thrive in saline conditions and gains a selective ecological advantage over other soil-dwelling microorganisms. However, little is known about how an elevated NaCl concentration affects survival and adaptive changes in this pathogen. In this study, we examined the adaptive changes in six isolates of B. pseudomallei after growth in Luria-Bertani medium containing different concentrations of NaCl at 37°C for 6 hr. The bacteria were then investigated for resistance to heat at 50°C and killing by hydrogen peroxide (H2 O2). In addition, flagellar production, biofilm formation, and the plaque formation efficiency of B. pseudomallei after culture in saline conditions were observed. In response to exposure to 150 and 300 mmol L[-1] NaCl, all B. pseudomallei isolates showed significantly increased thermal tolerance, oxidative resistance, and plaque-forming efficiency. However, NaCl exposure notably decreased the number of B. pseudomallei flagella. Taken together, these results provide insight into the adaptations of B. pseudomallei that might be crucial for survival and persistence in the host and/or endemic environments with high salinity.}, } @article {pmid28642143, year = {2017}, author = {Danielli, LJ and Lopes, W and Vainstein, MH and Fuentefria, AM and Apel, MA}, title = {Biofilm formation by Microsporum canis.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {23}, number = {12}, pages = {941-942}, doi = {10.1016/j.cmi.2017.06.006}, pmid = {28642143}, issn = {1469-0691}, mesh = {Biofilms/*growth & development ; Humans ; Microscopy, Electron, Scanning ; Microsporum/*physiology/ultrastructure ; Mycelium/ultrastructure ; Tinea Capitis/microbiology ; }, } @article {pmid28641301, year = {2017}, author = {Staun Larsen, L and Baelum, V and Tenuta, LMA and Richards, A and Nyvad, B}, title = {Fluoride in Dental Biofilm Varies across Intra-Oral Regions.}, journal = {Caries research}, volume = {51}, number = {4}, pages = {402-409}, doi = {10.1159/000475510}, pmid = {28641301}, issn = {1421-976X}, mesh = {Adult ; Aged ; Aged, 80 and over ; *Biofilms ; Cross-Sectional Studies ; Female ; Fluorides/*analysis ; Humans ; Male ; Middle Aged ; *Mouth ; Saliva/*chemistry ; Young Adult ; }, abstract = {Information on differences in biofilm fluoride concentration across intra-oral regions may help explain the distribution of caries within the dentition. The aim of this cross-sectional study was to describe the fluoride concentration in saliva and in biofilm fluid and biofilm solids across 6 intra-oral regions. Unstimulated whole saliva was collected from 42 participants and biofilm harvested from the buccal sites in the 4 molar and 2 anterior regions. Samples were collected at least 1 h after use of fluoride dentifrice. No attempt was made to control the participants' food consumption or use of other topical agents. Centrifuged saliva, biofilm fluid, and biofilm solids were analysed for fluoride using a fluoride ion-selective electrode, adapted for microanalysis. Fluoride in biofilm varied across intra-oral regions. The mean biofilm fluid fluoride concentrations across the oral cavity ranged from 11.6 to 16.8 µM, being statistically significantly higher in the upper anterior region than in any other region. In all regions the fluoride concentration in biofilm fluid was higher than in saliva. For biofilm solids the fluoride concentration was highest in the lower anterior region (2,461 μmol/kg) and lowest in the lower molar regions (388 and 406 μmol/kg, respectively). Within biofilm, the solids contained most of the fluoride (81 to >99%). The biofilm fluid fluoride concentration was significantly positively associated with salivary fluoride and only marginally associated with that of biofilm solids. In conclusion, this study has shown pronounced differences in fluoride distribution across intra-oral regions and compartments. This shows that the sampling site is a crucial factor for studies of biofilm fluoride.}, } @article {pmid28639672, year = {2017}, author = {Lin, F and Li, C and Dong, L and Fu, D and Chen, Z}, title = {Imaging biofilm-encased microorganisms using carbon dots derived from L. plantarum.}, journal = {Nanoscale}, volume = {9}, number = {26}, pages = {9056-9064}, doi = {10.1039/c7nr01975k}, pmid = {28639672}, issn = {2040-3372}, mesh = {*Biofilms ; Carbon/*chemistry ; *Lactobacillus plantarum ; Microscopy, Confocal ; Quantum Dots/*chemistry ; }, abstract = {Imaging biofilm-encased microorganisms is challenging due to them being shielded by a sticky and strong extracellular polymeric substance matrix that blocks the penetration of dyes, but is especially important for biofilm study. Here, carbon dots, namely CDs-605, were used for successfully imaging biofilm-encased microorganisms. We demonstrated that such CDs-605 could be easily synthesized from L. plantarum by one-step hydrothermal carbonization. The negatively charged CDs-605 were composed of C, H, O, N, P, and S and contained various functional groups, including -OH, -COOH, and -CONH-. For the first time, CDs-605 were found to be capable of imaging biofilm-encased microorganisms, including E. coli, S. oneidensis, P. aeruginosa, S. aures, and T. reesei, demonstrating that the labeling is universal. The labeling method based on CDs-605 did not require incubation, protection from light, or washing, which makes it very convenient. Additionally, CDs-605 did not disturb the biofilm and displayed better photostability compared to the commercial counterpart. CDs-605 can serve as a simple, yet powerful staining agent for biofilm-embedded microorganism imaging, which is vital for gaining a fundamental understanding of biofilm formation and dispersal.}, } @article {pmid28639245, year = {2018}, author = {Vuotto, C and Grosso, F and Longo, F and Balice, MP and de Barros, MC and Peixe, L and Donelli, G}, title = {Biofilm-Forming Ability and Clonality in Acinetobacter baumannii Strains Isolated from Urine Samples and Urinary Catheters in Different European Hospitals.}, journal = {Advances in experimental medicine and biology}, volume = {1057}, number = {}, pages = {73-83}, doi = {10.1007/5584_2017_70}, pmid = {28639245}, issn = {0065-2598}, mesh = {Acinetobacter Infections/*urine ; Acinetobacter baumannii/classification/*growth & development ; Anti-Bacterial Agents ; Bacterial Proteins ; *Biofilms ; Electrophoresis, Gel, Pulsed-Field ; Europe ; Hospitals ; Humans ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Urinary Catheters/*microbiology ; beta-Lactamases ; }, abstract = {OBJECTIVE: Biofilm formation has been associated with the persistence of Acinetobacter baumannii in hospital settings and its propensity to cause infection. We investigated the adhesion ability and clonality of 128 A. baumannii isolates recovered from urine and urinary catheters of patients admitted to 5 European hospitals during 1991-2013.

METHODS: Isolates identification was confirmed by rpoB sequencing and by the presence of blaOXA-51. The presence of carbapenemases was detected by PCR. Clonality was determined by Sequence Group (SG) identification, Pulsed field gel electrophoresis (PFGE) and Multilocus sequence typing. Adhesion ability was defined by quantitative biofilm production assay and biofilms were characterized by Confocal Laser Microscopy and Scanning Electron Microscopy.

RESULTS: The 128 isolates, either resistant (85.9%) or susceptible (14.1%) to carbapenems, and belonging to 50 different PFGE types and 24 different STs, were distributed among SG1 (67.2%), SG2 (10.2%) and other allelic profiles (22.7%). ST218 was the most frequent ST, corresponding to 54,5% of the isolates collected between 2011 and 2013. Among the 109 isolates showing resistance to at least 1 carbapenem, 55% revealed the presence of an acquired carbapenem-hydrolyzing class D - lactamases (CHDL): blaOXA-23 were the most frequent gene detected from 2008 onwards (75%). Among all the clinical isolates, 42.2% were strong biofilm producers, with the older isolates having the highest adhesion ability. Most isolates recovered later, belonging to ST218 and harbouring blaOXA-23, were homogeneously less adhesive.

CONCLUSIONS: An evolution towards a decrease in adhesion ability and a CHDL content change was observed along the years in several European countries.}, } @article {pmid28638805, year = {2017}, author = {Brown, LR and Caulkins, RC and Schartel, TE and Rosch, JW and Honsa, ES and Schultz-Cherry, S and Meliopoulos, VA and Cherry, S and Thornton, JA}, title = {Increased Zinc Availability Enhances Initial Aggregation and Biofilm Formation of Streptococcus pneumoniae.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {233}, pmid = {28638805}, issn = {2235-2988}, support = {P20 GM103646/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Autolysis/microbiology ; Biofilms/*drug effects/*growth & development ; Cell Line ; Copper/metabolism ; Female ; Host-Pathogen Interactions ; Humans ; Hydrogen Peroxide ; Manganese/metabolism ; Mice, Inbred C57BL ; Microbial Viability ; Microscopy, Electron, Scanning ; Mutation ; N-Acetylmuramoyl-L-alanine Amidase/genetics ; Pneumococcal Infections/*microbiology ; Pyruvate Oxidase/metabolism ; Streptococcus pneumoniae/*drug effects/*growth & development/*metabolism/pathogenicity ; Virulence Factors ; Zinc/*pharmacology ; }, abstract = {Bacteria growing within biofilms are protected from antibiotics and the immune system. Within these structures, horizontal transfer of genes encoding virulence factors, and promoting antibiotic resistance occurs, making biofilms an extremely important aspect of pneumococcal colonization and persistence. Identifying environmental cues that contribute to the formation of biofilms is critical to understanding pneumococcal colonization and infection. Iron has been shown to be essential for the formation of pneumococcal biofilms; however, the role of other physiologically important metals such as copper, zinc, and manganese has been largely neglected. In this study, we investigated the effect of metals on pneumococcal aggregation and early biofilm formation. Our results show that biofilms increase as zinc concentrations increase. The effect was found to be zinc-specific, as altering copper and manganese concentrations did not affect biofilm formation. Scanning electron microscopy analysis revealed structural differences between biofilms grown in varying concentrations of zinc. Analysis of biofilm formation in a mutant strain lacking the peroxide-generating enzyme pyruvate oxidase, SpxB, revealed that zinc does not protect against pneumococcal H2O2. Further, analysis of a mutant strain lacking the major autolysin, LytA, indicated the role of zinc as a negative regulator of LytA-dependent autolysis, which could affect biofilm formation. Additionally, analysis of cell-cell aggregation via plating and microscopy revealed that high concentrations of zinc contribute to intercellular interaction of pneumococci. The findings from this study demonstrate that metal availability contributes to the ability of pneumococci to form aggregates and subsequently, biofilms.}, } @article {pmid28638368, year = {2017}, author = {Liu, Q and Liu, B and Li, W and Zhao, X and Zuo, W and Xing, D}, title = {Impact of Ferrous Iron on Microbial Community of the Biofilm in Microbial Fuel Cells.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {920}, pmid = {28638368}, issn = {1664-302X}, abstract = {The performance of microbial electrochemical cells depends upon microbial community structure and metabolic activity of the electrode biofilms. Iron as a signal affects biofilm development and enrichment of exoelectrogenic bacteria. In this study, the effect of ferrous iron on microbial communities of the electrode biofilms in microbial fuel cells (MFCs) was investigated. Voltage production showed that ferrous iron of 100 μM facilitated MFC start-up compared to 150 μM, 200 μM, and without supplement of ferrous iron. However, higher concentration of ferrous iron had an inhibitive influence on current generation after 30 days of operation. Illumina Hiseq sequencing of 16S rRNA gene amplicons indicated that ferrous iron substantially changed microbial community structures of both anode and cathode biofilms. Principal component analysis showed that the response of microbial communities of the anode biofilms to higher concentration of ferrous iron was more sensitive. The majority of predominant populations of the anode biofilms in MFCs belonged to Geobacter, which was different from the populations of the cathode biofilms. An obvious shift of community structures of the cathode biofilms occurred after ferrous iron addition. This study implied that ferrous iron influenced the power output and microbial community of MFCs.}, } @article {pmid28634238, year = {2017}, author = {Sanchez, BC and Chang, C and Wu, C and Tran, B and Ton-That, H}, title = {Electron Transport Chain Is Biochemically Linked to Pilus Assembly Required for Polymicrobial Interactions and Biofilm Formation in the Gram-Positive Actinobacterium Actinomyces oris.}, journal = {mBio}, volume = {8}, number = {3}, pages = {}, pmid = {28634238}, issn = {2150-7511}, support = {R01 DE017382/DE/NIDCR NIH HHS/United States ; R01 DE025015/DE/NIDCR NIH HHS/United States ; }, mesh = {Actinomyces/genetics/growth & development/metabolism/*physiology ; *Bacterial Adhesion ; Biofilms/*growth & development ; DNA Transposable Elements ; *Electron Transport ; Fimbriae, Bacterial/*metabolism ; Genetic Testing ; Mutagenesis, Insertional ; *Organelle Biogenesis ; Streptococcus oralis/*physiology ; }, abstract = {The Gram-positive actinobacteria Actinomyces spp. are key colonizers in the development of oral biofilms due to the inherent ability of Actinomyces to adhere to receptor polysaccharides on the surface of oral streptococci and host cells. This receptor-dependent bacterial interaction, or coaggregation, requires a unique sortase-catalyzed pilus consisting of the pilus shaft FimA and the coaggregation factor CafA forming the pilus tip. While the essential role of the sortase machine SrtC2 in pilus assembly, biofilm formation, and coaggregation has been established, little is known about trans-acting factors contributing to these processes. We report here a large-scale Tn5 transposon screen for mutants defective in Actinomyces oris coaggregation with Streptococcus oralis We obtained 33 independent clones, 13 of which completely failed to aggregate with S. oralis, and the remainder of which exhibited a range of phenotypes from severely to weakly defective coaggregation. The former had Tn5 insertions in fimA, cafA, or srtC2, as expected; the latter were mapped to genes coding for uncharacterized proteins and various nuo genes encoding the NADH dehydrogenase subunits. Electron microscopy and biochemical analyses of mutants with nonpolar deletions of nuo genes and ubiE, a menaquinone C-methyltransferase-encoding gene downstream of the nuo locus, confirmed the pilus and coaggregation defects. Both nuoA and ubiE mutants were defective in oxidation of MdbA, the major oxidoreductase required for oxidative folding of pilus proteins. Furthermore, supplementation of the ubiE mutant with exogenous menaquinone-4 rescued the cell growth and pilus defects. Altogether, we propose that the A. oris electron transport chain is biochemically linked to pilus assembly via oxidative protein folding.IMPORTANCE The Gram-positive actinobacterium A. oris expresses adhesive pili, or fimbriae, that are essential to biofilm formation and Actinomyces interactions with other bacteria, termed coaggregation. While the critical role of the conserved sortase machine in pilus assembly and the disulfide bond-forming catalyst MdbA in oxidative folding of pilins has been established, little is known about other trans-acting factors involved in these processes. Using a Tn5 transposon screen for mutants defective in coaggregation with Streptococcus oralis, we found that genetic disruption of the NADH dehydrogenase and menaquinone biosynthesis detrimentally alters pilus assembly. Further biochemical characterizations determined that menaquinone is important for reactivation of MdbA. This study supports the notion that the electron transport chain is biochemically linked to pilus assembly in A. oris via oxidative folding of pilin precursors.}, } @article {pmid28633052, year = {2017}, author = {Vetas, D and Dimitropoulou, E and Mitropoulou, G and Kourkoutas, Y and Giaouris, E}, title = {Disinfection efficiencies of sage and spearmint essential oils against planktonic and biofilm Staphylococcus aureus cells in comparison with sodium hypochlorite.}, journal = {International journal of food microbiology}, volume = {257}, number = {}, pages = {19-25}, doi = {10.1016/j.ijfoodmicro.2017.06.003}, pmid = {28633052}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Disinfection ; Humans ; Mentha spicata/*chemistry ; Microbial Sensitivity Tests ; Oils, Volatile/*pharmacology ; Plankton/*drug effects/growth & development/physiology ; Plant Extracts/*pharmacology ; Sodium Hypochlorite/*pharmacology ; Staphylococcus aureus/*drug effects/growth & development/physiology ; }, abstract = {Staphylococcus aureus causes human infections and foodborne intoxications. This study explored the potential antibacterial actions of sage and spearmint essential oils (EOs) against both its planktonic and biofilm cells, in comparison with sodium hypochlorite (NaOCl), a commonly applied chemical sanitizer. Initially, the minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each plant mixture were determined against planktonic cultures, following growth at 30°C for 24h. Stationary phase planktonic bacteria were then individually exposed for 6min to either each EO (applied at 1-2×MBC; 2.5-5%), or NaOCl (250-450ppm). These were also left to form biofilms on 96-well polystyrene microplates, at 30°C for 96h, with medium renewal at 48h, in the presence of 10 different concentrations of each EO, expanding from sub- to super-inhibitory for planktonic growth, and the minimum biofilm inhibitory concentrations (MBICs; >90% inhibition) of each plant mixture were calculated. Formed biofilms were finally exposed for 6min to either each EO (applied at 2-6×MBC; 5-15%), or NaOCl (7500-25,000ppm; applied either alone or in combination with each EO at 5%). Results showed that both EOs presented MIC and MBC equal to 1.25 and 2.5%, respectively. As expected, their application at their MIC and above significantly inhibited biofilm formation, while spearmint EO was still able to cause this at ½ of its MIC, with MBICs equal to 1.25 and 0.63% for sage and spearmint EOs, respectively. Alarmingly, the application of both EOs at 1/8 to 1/16 of their MIC further increased biofilm formation. Regarding biofilm disinfection experiments, the individual application of each EO against the pre-established sessile communities resulted in log decrease ranges of 0.8-3logCFU/cm[2], while in the case of NaOCl application (either alone or combined with each EO), the observed reductions never exceeded 1.7logCFU/cm[2]. These last results highlight the great antimicrobial recalcitrance of biofilm communities, found here to be ca. 100 times more resistant to NaOCl compared to planktonic ones, and stress the urgent need for further research on alternative, adequate and safe disinfection strategies to control them in food processing and other environments.}, } @article {pmid28632895, year = {2017}, author = {Galica, T and Hrouzek, P and Mareš, J}, title = {Genome mining reveals high incidence of putative lipopeptide biosynthesis NRPS/PKS clusters containing fatty acyl-AMP ligase genes in biofilm-forming cyanobacteria.}, journal = {Journal of phycology}, volume = {53}, number = {5}, pages = {985-998}, doi = {10.1111/jpy.12555}, pmid = {28632895}, issn = {1529-8817}, mesh = {Bacterial Proteins/*genetics ; Computational Biology ; Cyanobacteria/*genetics ; *Genome, Bacterial ; Peptide Synthases/*genetics ; Polyketide Synthases/*genetics ; }, abstract = {Cyanobacterial lipopeptides have antimicrobial and antifungal bioactivities with potential for use in pharmaceutical research. However, due to their hemolytic activity and cytotoxic effects on human cells, they may pose a health issue if produced in substantial amounts in the environment. In bacteria, lipopeptides can be synthesized via several well-evidenced mechanisms. In one of them, fatty acyl-AMP ligase (FAAL) initiates biosynthesis by activation of a fatty acyl residue. We have performed a bioinformatic survey of the cyanobacterial genomic information available in the public databases for the presence of FAAL-containing non-ribosomal peptide synthetase/polyketide synthetase (NRPS/PKS) biosynthetic clusters, as a genetic basis for lipopeptide biosynthesis. We have identified 79 FAAL genes associated with various NRPS/PKS clusters in 16% of 376 cyanobacterial genomic assemblies available, suggesting that FAAL is frequently incorporated in NRPS/PKS biosynthetases. FAAL was present either as a stand-alone protein or fused either to NRPS or PKS. Such clusters were more frequent in derived phylogenetic lineages with larger genome sizes, which is consistent with the general pattern of NRPS/PKS pathways distribution. The putative lipopeptide clusters were more frequently found in genomes of cyanobacteria that live attached to surfaces and are capable of forming microbial biofilms. While lipopeptides are known in other bacterial groups to play a role in biofilm formation, motility, and colony expansion, their functions in cyanobacterial biofilms need to be tested experimentally. According to our data, benthic and terrestrial cyanobacteria should be the focus of a search for novel candidates for lipopeptide drug synthesis and the monitoring of toxic lipopeptide production.}, } @article {pmid28629757, year = {2017}, author = {Sabir, N and Ikram, A and Zaman, G and Satti, L and Gardezi, A and Ahmed, A and Ahmed, P}, title = {Bacterial biofilm-based catheter-associated urinary tract infections: Causative pathogens and antibiotic resistance.}, journal = {American journal of infection control}, volume = {45}, number = {10}, pages = {1101-1105}, doi = {10.1016/j.ajic.2017.05.009}, pmid = {28629757}, issn = {1527-3296}, mesh = {Adolescent ; Adult ; Aged ; Bacteria/*classification/*drug effects/isolation & purification ; Bacteriological Techniques ; Biofilms/*growth & development ; Catheter-Related Infections/*epidemiology/microbiology ; Catheters/*microbiology ; Child ; Cross-Sectional Studies ; *Drug Resistance, Bacterial ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Urinary Tract Infections/*epidemiology/microbiology ; Young Adult ; }, abstract = {BACKGROUND: We sought to determine the incidence of bacterial biofilm-based catheter-associated urinary tract infections, identify variables affecting biofilm formation, and identify etiologic bacterial pathogens and antibiotic-resistance patterns associated with biofilm-based catheter-associated urinary tract infections (CAUTIs) in our setup.

METHODS: Patients who developed at least 2 symptoms of urinary tract infection after at least 2 days of indwelling urinary catheters were included. Urine was collected aseptically from catheter tubing and processed per standard microbiologic practices. Bacterial pathogens were identified on the basis of gram staining, colony morphology, and biochemical reactions. The detection of the biofilm was done using the tube adherence method. Drug susceptibility testing was done using the Kirby-Bauer disc diffusion method.

FINDINGS: Biofilm was detected in 73.4% isolates, whereas 26.6% of isolates were nonbiofilm producers. Mean duration of catheterization after which biofilm was detected was 5.01 ± 1.31 days. A latex catheter was used in 69.5% of patients, whereas a silicone catheter was used in 30.4% of patients. Escherichia coli was found to be the most common pathogen isolated (52.3%), whereas Enterobacter cloacae exhibited the highest biofilm production (87.5%) among isolated pathogens. Among biofilm producers, the highest resistance was observed with ampicillin (100%). Fosfomycin exhibited the lowest resistance (17.2%). Significant association with biofilm was detected for gender, duration of catheterization, and type of catheter.

CONCLUSION: Biofilm-based CAUTI is an emerging problem. E coli was the most frequent isolate. High antibiotic resistance was observed in biofilm-producing strains. Using the variables affecting biofilm formation, tailored intervention strategies can be implemented to reduce biofilm-based CAUTIs.}, } @article {pmid28628237, year = {2017}, author = {Li, L and Banerjee, A and Bischof, LF and Maklad, HR and Hoffmann, L and Henche, AL and Veliz, F and Bildl, W and Schulte, U and Orell, A and Essen, LO and Peeters, E and Albers, SV}, title = {Wing phosphorylation is a major functional determinant of the Lrs14-type biofilm and motility regulator AbfR1 in Sulfolobus acidocaldarius.}, journal = {Molecular microbiology}, volume = {105}, number = {5}, pages = {777-793}, doi = {10.1111/mmi.13735}, pmid = {28628237}, issn = {1365-2958}, mesh = {Amino Acid Sequence ; Archaeal Proteins/metabolism ; Biofilms/growth & development ; DNA/metabolism ; DNA-Binding Proteins/metabolism ; Gene Expression Regulation, Archaeal/genetics ; Helix-Turn-Helix Motifs ; Phosphorylation ; Protein Structural Elements ; Sulfolobus/genetics ; Sulfolobus acidocaldarius/*genetics/*metabolism ; Transcription Factors/metabolism ; }, abstract = {In response to a variety of environmental cues, prokaryotes can switch between a motile and a sessile, biofilm-forming mode of growth. The regulatory mechanisms and signaling pathways underlying this switch are largely unknown in archaea but involve small winged helix-turn-helix DNA-binding proteins of the archaea-specific Lrs14 family. Here, we study the Lrs14 member AbfR1 of Sulfolobus acidocaldarius. Small-angle X-ray scattering data are presented, which are consistent with a model of dimeric AbfR1 in which dimerization occurs via an antiparallel coiled coil as suggested by homology modeling. Furthermore, solution structure data of AbfR1-DNA complexes suggest that upon binding DNA, AbfR1 induces deformations in the DNA. The wing residues tyrosine 84 and serine 87, which are phosphorylated in vivo, are crucial to establish stable protein-DNA contacts and their substitution with a negatively charged glutamate or aspartate residue inhibits formation of a nucleoprotein complex. Furthermore, mutation abrogates the cellular abundance and transcription regulatory function of AbfR1 and thus affects the resulting biofilm and motility phenotype of S. acidocaldarius. This work establishes a novel wHTH DNA-binding mode for Lrs14-like proteins and hints at an important role for protein phosphorylation as a signal transduction mechanism for the control of biofilm formation and motility in archaea.}, } @article {pmid28627772, year = {2017}, author = {Jung, SJ and Park, SY and Kim, SE and Kang, I and Park, J and Lee, J and Kim, CM and Chung, MS and Ha, SD}, title = {Bactericidal Effect of Calcium Oxide (Scallop-Shell Powder) Against Pseudomonas aeruginosa Biofilm on Quail Egg Shell, Stainless Steel, Plastic, and Rubber.}, journal = {Journal of food science}, volume = {82}, number = {7}, pages = {1682-1687}, doi = {10.1111/1750-3841.13753}, pmid = {28627772}, issn = {1750-3841}, mesh = {Animal Shells/*chemistry ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Calcium Compounds/*pharmacology ; Ovum/*microbiology ; Oxides/*pharmacology ; Pectinidae/*chemistry ; Plastics/analysis ; Pseudomonas aeruginosa/*drug effects/physiology ; Quail/microbiology ; Rubber/analysis ; Stainless Steel ; }, abstract = {The aim of this study was to evaluate the bactericidal effect of calcium oxide (CaO) against Pseudomonas aeruginosa biofilms on quail eggshells and major egg contacting surfaces (stainless steel, plastic, and rubber). The samples were subjected to CaO treatments (0%, 0.01%, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30%) for 1 min. All the CaO treatments significantly reduced P. aeruginosa biofilms on all tested surfaces as compared to controls. In comparison of biofilm stability, the strongest and most resistant biofilm was formed on eggshell against the CaO treatment, followed by rubber, stainless steel, and plastic. In evaluation of bactericidal effect, the largest reduction (3.16 log CFU) was observed in plastic even at the lowest concentration of CaO (0.01%), whereas the least reduction was found in eggshells, regardless of CaO concentration. In addition, stainless steel showed a significant reduction in biofilm formation at all concentrations except 0.10% to 0.15% CaO. At 0.30% CaO, the reduction of P. aeruginosa in biofilms on stainless steel, plastic, rubber, and eggshell were 5.48, 6.37, 4.87, and 3.14 log CFU/cm[2] (CFU/egg), respectively. Biofilm reduction after CaO treatment was also observed by field emission scanning electron microscopy (FE-SEM). Based on the FE-SEM images, we observed that P. aeruginosa biofilms formed compact aggregations on eggshell surfaces with CaO treatments up to 0.30%. More specifically, a 0.20% CaO treatment resulted in the reductions of 3 to 6 log CFU in all materials.}, } @article {pmid28627304, year = {2018}, author = {Kot, B and Wierzchowska, K and Grużewska, A and Lohinau, D}, title = {The effects of selected phytochemicals on biofilm formed by five methicillin-resistant Staphylococcus aureus.}, journal = {Natural product research}, volume = {32}, number = {11}, pages = {1299-1302}, doi = {10.1080/14786419.2017.1340282}, pmid = {28627304}, issn = {1478-6427}, mesh = {Acrolein/analogs & derivatives/pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Caffeic Acids/pharmacology ; Coumaric Acids/pharmacology ; Geranium/chemistry ; Humans ; Lavandula ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification ; Microbial Sensitivity Tests ; Oils, Volatile/chemistry/pharmacology ; Plant Oils/chemistry/pharmacology ; Propionates ; Thymus Plant/chemistry ; }, abstract = {The aim of this study was to evaluate the ability of 0.1% thyme oil (TO), trans-cinnamaldehyde (TC), ferulic acid (FA), p-coumaric acid (p-CA), caffeic acid (CA), lavender essential oil (LO), geranium essential oil (GO) and tee tree oil (TTO) to control biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA) strains. Depending on the strains, TO reduced 59.7-85% of biofilm mass, while TC 52.9-82.4% after 48 h of treatment. Reduction of metabolic activity of biofilms in ranges 79.3-86% and 85.9-88.7% was observed after 48 h of TC and TO of treatment, respectively. In the case of some strains, reduction of biofilm mass in the presence of FA, CA, GO, LO and TTO was not observed. This study showed that TO and TC might have therapeutic potential as an inhibitory agents for use in MRSA biofilm-related infections.}, } @article {pmid28625077, year = {2017}, author = {Lafaurie, GI and Sabogal, MA and Castillo, DM and Rincón, MV and Gómez, LA and Lesmes, YA and Chambrone, L}, title = {Microbiome and Microbial Biofilm Profiles of Peri-Implantitis: A Systematic Review.}, journal = {Journal of periodontology}, volume = {88}, number = {10}, pages = {1066-1089}, doi = {10.1902/jop.2017.170123}, pmid = {28625077}, issn = {1943-3670}, mesh = {*Biofilms ; Humans ; *Microbiota ; Peri-Implantitis/*microbiology ; Periodontitis/*microbiology ; }, abstract = {BACKGROUND: This systematic review assesses microbiologic profiles of peri-implantitis, periodontitis, and healthy implants based on studies that evaluated microbial biofilms and entire microbiomes to establish their similarities and differences.

METHODS: The Medical Literature Analysis and Retrieval System Online via PubMed, Excerpta Medica Database, and Cochrane Central Register of Controlled Trials, were searched without language restrictions through July 30, 2016. Observational studies that evaluated microbial profiles or entire microbiomes of peri-implantitis compared with healthy implants or periodontitis were considered eligible for inclusion. A descriptive summary was created to determine quantity of data and interstudy variations.

RESULTS: Of 126 potentially eligible articles, 26 were included in this study. Twenty-one of these articles evaluated the microbiologic profile of peri-implantitis versus healthy implants or periodontitis using conventional microbiologic techniques. Five articles evaluated the entire microbiome using genomic sequencing. Teeth with periodontitis, healthy implants, or implants with peri-implantitis were colonized by periodontal microorganisms. Porphyromonas gingivalis and especially Prevotella intermedius/nigrescens were often identified at peri-implantitis sites. Peri-implantitis sites were also colonized by uncultivable asaccharolytic anaerobic Gram-positive rods and anaerobic Gram-negative rods, which were not frequently identified in teeth with periodontitis or healthy implants. Opportunistic microorganisms were not found very frequently in peri-implantitis sites.

CONCLUSIONS: Peri-implantitis represents a heterogeneous mixed infection that includes periodontopathic microorganisms, uncultivable asaccharolytic anaerobic Gram-positive rods and other uncultivable Gram-negative rods, and, rarely, opportunistic microorganisms such as enteric rods and Staphylococcus aureus. Sequencing methods that evaluate the entire microbiome improve identification of microorganisms associated with peri-implantitis.}, } @article {pmid28624271, year = {2017}, author = {Goetz, C and Tremblay, YDN and Lamarche, D and Blondeau, A and Gaudreau, AM and Labrie, J and Malouin, F and Jacques, M}, title = {Coagulase-negative staphylococci species affect biofilm formation of other coagulase-negative and coagulase-positive staphylococci.}, journal = {Journal of dairy science}, volume = {100}, number = {8}, pages = {6454-6464}, doi = {10.3168/jds.2017-12629}, pmid = {28624271}, issn = {1525-3198}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Coagulase/*metabolism ; Female ; Humans ; Mastitis, Bovine/*microbiology ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus/*enzymology/physiology ; Staphylococcus aureus ; }, abstract = {Coagulase-negative staphylococci (CNS) are considered to be commensal bacteria in humans and animals, but are now also recognized as etiological agents in several infections, including bovine mastitis. Biofilm formation appears to be an important factor in CNS pathogenicity. Furthermore, some researchers have proposed that CNS colonization of the intramammary environment has a protective effect against other pathogens. The mechanisms behind the protective effect of CNS have yet to be characterized. The aim of this study was to evaluate the effect of CNS isolates with a weak-biofilm phenotype on the biofilm formation of other staphylococcal isolates. We selected 10 CNS with a weak-biofilm phenotype and 30 staphylococcal isolates with a strong-biofilm phenotype for this study. We measured biofilm production by individual isolates using a standard polystyrene microtiter plate assay and compared the findings with biofilm produced in mixed cultures. We confirmed the results using confocal microscopy and a microfluidic system with low shear force. Four of the CNS isolates with a weak-biofilm phenotype (Staphylococcus chromogenes C and E and Staphylococcus simulans F and H) significantly reduced biofilm formation in approximately 80% of the staphylococcal species tested, including coagulase-positive Staphylococcus aureus. The 4 Staph. chromogenes and Staph. simulans isolates were also able to disperse pre-established biofilms, but to a lesser extent. We also performed a deferred antagonism assay and recorded the number of colony-forming units in the mixed-biofilm assays on differential or selective agar plates. Overall, CNS with a weak-biofilm phenotype did not inhibit the growth of isolates with a strong-biofilm phenotype. These results suggest that some CNS isolates can negatively affect the ability of other staphylococcal isolates and species to form biofilms via a mechanism that does not involve growth inhibition.}, } @article {pmid28623661, year = {2017}, author = {Dybowska-Sarapuk, Ł and Kotela, A and Krzemiński, J and Wróblewska, M and Marchel, H and Romaniec, M and Łęgosz, P and Jakubowska, M}, title = {Graphene Nanolayers as a New Method for Bacterial Biofilm Prevention: Preliminary Results.}, journal = {Journal of AOAC International}, volume = {100}, number = {4}, pages = {900-904}, doi = {10.5740/jaoacint.17-0164}, pmid = {28623661}, issn = {1944-7922}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheters, Indwelling/microbiology ; Equipment Contamination/*prevention & control ; Graphite/*pharmacology ; *Metal Nanoparticles ; Silver ; Staphylococcus epidermidis/drug effects ; }, abstract = {Biofilms are microbial communities of surface-attached cells embedded in a self-produced extracellular matrix. They have been found to play a role in a wide variety of infections, including catheter-related urinary tract and bloodstream infections, and, therefore remain a significant source of morbidity and mortality among the world's population. Recently, much attention has been devoted to the prevention of biofilm formation on implant surfaces. Nanomaterials such as graphene, characterized by antibacterial activity and low toxicity to human cells, are promising candidates for biomedical applications. This study investigates the antibacterial efficiency of graphene and specially produced graphene decorated with silver nanoparticles, obtained by one of the methods of printed electronics (spray-coating system). These methods are not only economical, but also enable the printing of layers of various thicknesses on different types of materials, including flexible and nonplanar substrates. The aim of the study was to reveal the ability of graphene and graphene-nanosilver layers to prevent the formation of Staphylococcus epidermidis biofilm on the surface of a Foley catheter.}, } @article {pmid28622569, year = {2017}, author = {van Hengel, IAJ and Riool, M and Fratila-Apachitei, LE and Witte-Bouma, J and Farrell, E and Zadpoor, AA and Zaat, SAJ and Apachitei, I}, title = {Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus.}, journal = {Biomaterials}, volume = {140}, number = {}, pages = {1-15}, doi = {10.1016/j.biomaterials.2017.02.030}, pmid = {28622569}, issn = {1878-5905}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage/*pharmacology ; Biofilms/drug effects ; Bone Substitutes/chemistry ; Cell Line ; Electrolysis ; Femur/microbiology/surgery ; Humans ; Lasers ; Materials Testing ; Metal Nanoparticles/chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Mice ; Oxidation-Reduction ; Porosity ; Prostheses and Implants/adverse effects/*microbiology ; Silver/*administration & dosage/*pharmacology ; Staphylococcal Infections/etiology/*prevention & control ; Titanium/chemistry ; }, abstract = {Implant-associated infection and limited longevity are two major challenges that orthopedic devices need to simultaneously address. Additively manufactured porous implants have recently shown tremendous promise in improving bone regeneration and osseointegration, but, as any conventional implant, are threatened by infection. In this study, we therefore used rational design and additive manufacturing in the form of selective laser melting (SLM) to fabricate porous titanium implants with interconnected pores, resulting in a 3.75 times larger surface area than corresponding solid implants. The SLM implants were biofunctionalized by embedding silver nanoparticles in an oxide surface layer grown using plasma electrolytic oxidation (PEO) in Ca/P-based electrolytes. The PEO layer of the SLM implants released silver ions for at least 28 days. X-ray diffraction analysis detected hydroxyapatite on the SLM PEO implants but not on the corresponding solid implants. In vitro and ex vivo assays showed strong antimicrobial activity of these novel SLM PEO silver-releasing implants, without any signs of cytotoxicity. The rationally designed SLM porous implants outperformed solid implants with similar dimensions undergoing the same biofunctionalization treatment. This included four times larger amount of released silver ions, two times larger zone of inhibition, and one additional order of magnitude of reduction in numbers of CFU in an ex vivo mouse infection model.}, } @article {pmid28620784, year = {2017}, author = {Eom, HJ and Park, W}, title = {Inhibitory Effect of Taurine on Biofilm Formation During Alkane Degradation in Acinetobacter oleivorans DR1.}, journal = {Microbial ecology}, volume = {74}, number = {4}, pages = {821-831}, pmid = {28620784}, issn = {1432-184X}, mesh = {Acinetobacter/*drug effects/*physiology ; Alkanes/*metabolism ; Antioxidants/*pharmacology ; Biodegradation, Environmental ; Biofilms/*drug effects ; Hydrophobic and Hydrophilic Interactions ; Quorum Sensing ; Taurine/*pharmacology ; }, abstract = {Taurine, 2-aminoethanesulfonate, is known to function as an antioxidant or membrane stabilizer in eukaryotic cells, but its role in bacteria has been poorly characterized. Biofilm formation of Acinetobacter oleivorans DR1 was significantly reduced by taurine only during alkane degradation, suggesting that taurine affects alkane-induced cell surface. Structurally similar compounds harboring an amine group such as hypotaurine or ethylenediamine have a similar effect, which was not observed with sulfonate-containing chemicals such as ethanesulfonic acid, hexanesulfonic acid. Our biochemical assays and physiological tests demonstrate that taurine reduced cell surface hydrophobicity, which resulted in interruption of the interactions between cells and oily substrate surfaces, such that cells utilized alkanes less effectively. Interestingly, taurine-mediated reduction of quorum sensing (QS) signal production and QS-control sapA gene expression indicated that membrane permeability of quorum signals was also interfered by taurine. Composition and biomass of extracellular polymeric saccharides were changed in taurine-amended conditions. Taken together, our data provide evidence that amine-containing taurine can inhibit biofilm formation of DR1 cells during alkane degradation by (i) changing cell surface charge and (ii) reducing membrane hydrophobicity and QS sensing.}, } @article {pmid28620360, year = {2017}, author = {Haque, MM and Oliver, MMH and Nahar, K and Alam, MZ and Hirata, H and Tsuyumu, S}, title = {CytR Homolog of Pectobacterium carotovorum subsp. carotovorum Controls Air-Liquid Biofilm Formation by Regulating Multiple Genes Involved in Cellulose Production, c-di-GMP Signaling, Motility, and Type III Secretion System in Response to Nutritional and Environmental Signals.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {972}, pmid = {28620360}, issn = {1664-302X}, abstract = {Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King's B at 27°C after 72 h incubation in static condition. The wild type also produced significantly higher quantities of AL biofilm on SOBGMg[-] (magnesium deprived) containing Cupper (Cu[2+]), Zinc (Zn[2+]), Manganese (Mn[2+]), Magnesium (Mg[2+]), and Calcium (Ca[2+]) compared to the ΔcytR mutant. Moreover, the wild type was produced higher amounts of biofilms compared to the mutant while responding to pH and osmotic stresses. The ΔfliC (encoding flagellin), flhD::Tn5 (encoding a master regulator) and ΔmotA (a membrane protein essential for flagellar rotation) mutants produced a lighter and more fragile AL biofilm on SOBG compared to their wild counterpart. All these mutants resulted in having weak bonds with the cellulose specific dye (Calcofluor) producing lower quantities of cellulose compared to the wild type. Gene expression analysis using mRNA collected from the AL biofilms showed that ΔcytR mutant significantly (P < 0.001) reduced the expressions of multiple genes responsible for cellulose production (bcsA, bcsE, and adrA), motility (flhD, fliA, fliC, and motA) and type III secretion system (hrpX, hrpL, hrpA, and hrpN) compared to the wild type. The CytR homolog was therefore, argued to be able to regulate the AL biofilm formation by controlling cellulose production, motility and T3SS in Pcc PC1. In addition, all the mutants exhibited poorer attachment to radish sprouts and AL biofilm cells of the wild type was resistant than stationary-phase and planktonic cells to acidity and oxidative stress compared to the same cells of the ΔcytR mutant. The results of this study therefore suggest that CytR homolog is a major determinant of Pcc PC1's virulence, attachment and its survival mechanism.}, } @article {pmid28619145, year = {2017}, author = {Wang, L and Zhao, X and Zhu, C and Xia, X and Qin, W and Li, M and Wang, T and Chen, S and Xu, Y and Hang, B and Sun, Y and Jiang, J and Richard, LP and Lei, L and Zhang, G and Hu, J}, title = {Thymol kills bacteria, reduces biofilm formation, and protects mice against a fatal infection of Actinobacillus pleuropneumoniae strain L20.}, journal = {Veterinary microbiology}, volume = {203}, number = {}, pages = {202-210}, doi = {10.1016/j.vetmic.2017.02.021}, pmid = {28619145}, issn = {1873-2542}, mesh = {Actinobacillus Infections/*drug therapy/microbiology ; Actinobacillus pleuropneumoniae/*drug effects/growth & development/pathogenicity ; Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Disease Models, Animal ; Female ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Thymol/*pharmacology ; Virulence ; }, abstract = {Actinobacillus pleuropneumoniae is the causative agent of the highly contagious and deadly respiratory infection porcine pleuropneumonia, resulting in serious losses to the pig industry worldwide. Alternative to antibiotics are urgently needed due to the serious increase in antimicrobial resistance. Thymol is a monoterpene phenol and efficiently kills a variety of bacteria. This study found that thymol has strong bactericidal effects on the A. pleuropneumoniae 5b serotype strain, an epidemic strain in China. Sterilization occurred rapidly, and the minimum inhibitory concentration (MIC) is 31.25μg/mL; the A. pleuropneumoniae density was reduced 1000 times within 10min following treatment with 1 MIC. Transmission electron microscopy (TEM) analysis revealed that thymol could rapidly disrupt the cell walls and cell membranes of A. pleuropneumoniae, causing leakage of cell contents and cell death. In addition, treatment with thymol at 0.5 MIC significantly reduced the biofilm formation of A. pleuropneumoniae. Quantitative RT-PCR results indicated that thymol treatment significantly increased the expression of the virulence genes purC, tbpB1 and clpP and down-regulated ApxI, ApxII and Apa1 expression in A. pleuropneumoniae. Therapeutic analysis of a murine model showed that thymol (20mg/kg) protected mice from a lethal dose of A. pleuropneumoniae, attenuated lung pathological lesions. This study is the first to report the use of thymol to treat A. pleuropneumoniae infection, establishing a foundation for the development of new antimicrobials.}, } @article {pmid28618083, year = {2017}, author = {Liu, W and Russel, J and Røder, HL and Madsen, JS and Burmølle, M and Sørensen, SJ}, title = {Low-abundant species facilitates specific spatial organization that promotes multispecies biofilm formation.}, journal = {Environmental microbiology}, volume = {19}, number = {7}, pages = {2893-2905}, doi = {10.1111/1462-2920.13816}, pmid = {28618083}, issn = {1462-2920}, mesh = {Actinobacteria/*growth & development ; Biofilms/*growth & development ; Microbiota/physiology ; Paenibacillus/*growth & development ; Quorum Sensing/physiology ; Stenotrophomonas/*growth & development ; Xanthomonas/*growth & development ; }, abstract = {Microorganisms frequently co-exist in matrix-embedded multispecies biofilms. Within biofilms, interspecies interactions influence the spatial organization of member species, which likely play an important role in shaping the development, structure and function of these communities. Here, a reproducible four-species biofilm, composed of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus, was established to study the importance of individual species spatial organization during multispecies biofilm development. We found that the growth of species that are poor biofilm formers, M. oxydans and P. amylolyticus, were highly enhanced when residing in the four-species biofilm. Interestingly, the presence of the low-abundant M. oxydans (0.5% of biomass volume) was observed to trigger changes in the composition of the four-species community. The other three species were crucially needed for the successful inclusion of M. oxydans in the four-species biofilm, where X. retroflexus was consistently positioned in the top layer of the mature four-species biofilm. These findings suggest that low abundance key species can significantly impact the spatial organization and hereby stabilize the function and composition of complex microbiomes.}, } @article {pmid28617874, year = {2017}, author = {Hwang, G and Liu, Y and Kim, D and Li, Y and Krysan, DJ and Koo, H}, title = {Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo.}, journal = {PLoS pathogens}, volume = {13}, number = {6}, pages = {e1006407}, pmid = {28617874}, issn = {1553-7374}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; R03 DE025728/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Candida albicans/genetics/*metabolism ; Cell Wall/enzymology/genetics/microbiology ; Dental Plaque/*microbiology ; Female ; Glucans/metabolism ; Humans ; Mannans/*metabolism ; Rats ; Rats, Sprague-Dawley ; Streptococcus mutans/*enzymology/genetics/*physiology ; }, abstract = {Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1-2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of GtfB-Candida interactions may provide new perspectives for devising effective therapies to disrupt this cross-kingdom relationship associated with an important childhood oral disease.}, } @article {pmid28617843, year = {2017}, author = {Habib, C and Yu, Y and Gozzi, K and Ching, C and Shemesh, M and Chai, Y}, title = {Characterization of the regulation of a plant polysaccharide utilization operon and its role in biofilm formation in Bacillus subtilis.}, journal = {PloS one}, volume = {12}, number = {6}, pages = {e0179761}, pmid = {28617843}, issn = {1932-6203}, mesh = {Bacillus subtilis/*physiology ; Bacterial Proteins/*biosynthesis ; Biofilms/*growth & development ; Operon/*physiology ; Polysaccharides/*metabolism ; Repressor Proteins/biosynthesis ; Rhizome/*microbiology ; beta-Galactosidase/biosynthesis ; }, abstract = {The soil bacterium Bacillus subtilis is often found in association with plants in the rhizosphere. Previously, plant polysaccharides have been shown to stimulate formation of root-associated multicellular communities, or biofilms, in this bacterium, yet the underlying mechanism is not fully understood. A five-gene gan operon (ganSPQAB) in B. subtilis has recently been shown to be involved in utilization of the plant-derived polysaccharide galactan. Despite these findings, molecular details about the regulation of the operon and the role of the operon in biofilm formation remain elusive. In this study, we performed comprehensive genetic analyses on the regulation of the gan operon. We show that this operon is regulated both by a LacI-like transcription repressor (GanR), which directly binds to pairs of inverted DNA repeats in the promoter region of the operon, and by the catabolite control protein A (CcpA). Derepression can be triggered by the presence of the inducer β-1,4-galactobiose, a hydrolysis product of galactan, or in situ when B. subtilis cells are associated with plant roots. In addition to the transcriptional regulation, the encoded ß-galactosidase GanA (by ganA), which hydrolyzes ß-1,4-galactobiose into galactose, is inhibited at the enzymatic level by the catalytic product galactose. Thus, the galactan utilization pathway is under complex regulation involving both positive and negative feedback mechanisms in B. subtilis. We discuss about the biological significance of such complex regulation as well as a hypothesis of biofilm induction by galactan via multiple mechanisms.}, } @article {pmid28616631, year = {2017}, author = {Yan, X and Gu, S and Shi, Y and Cui, X and Wen, S and Ge, J}, title = {The effect of emodin on Staphylococcus aureus strains in planktonic form and biofilm formation in vitro.}, journal = {Archives of microbiology}, volume = {199}, number = {9}, pages = {1267-1275}, doi = {10.1007/s00203-017-1396-8}, pmid = {28616631}, issn = {1432-072X}, support = {Grant No. 31101845//National Natural Science Foundation of China/ ; Grant No. LBH-Q12150//postdoctoral science-research developmental foundation of Heilongjiang Province/ ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Berberine/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Emodin/*pharmacology ; Gene Expression/drug effects ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Plankton/drug effects/microbiology ; Staphylococcus aureus/*drug effects/genetics ; }, abstract = {Staphylococcus aureus (S. aureus) is a Gram-positive pathogen and forms biofilm easily. Bacteria inside biofilms display an increased resistance to antibiotics and disinfectants. The objective of the current study was to assess the antimicrobial activities of emodin, 1,2,8-trihydroxy-6-methylanthraquinone, an anthraquinone derivative isolated from Polygonum cuspidatum and Rheum palmatum, against S. aureus CMCC26003 grown in planktonic and biofilm cultures in vitro. In addition, a possible synergistic effect between emodin and berberine chloride was evaluated. As quantified by crystal violet method, emodin significantly decreased S. aureus biofilm growth in a dose-dependent manner. The above findings were further supported by scanning electron microscopy. Moreover, the present study demonstrated that sub-MICs emodin obviously intervened the release of extracellular DNA and inhibited expression of the biofilm-related genes (cidA, icaA, dltB, agrA, sortaseA and sarA) by real-time RT-PCR. These results revealed a promising application for emodin as a therapeutic agent and an effective strategy to prevent S. aureus biofilm-related infections.}, } @article {pmid28613253, year = {2017}, author = {Rasamiravaka, T and Ngezahayo, J and Pottier, L and Ribeiro, SO and Souard, F and Hari, L and Stévigny, C and Jaziri, ME and Duez, P}, title = {Terpenoids from Platostoma rotundifolium (Briq.) A. J. Paton Alter the Expression of Quorum Sensing-Related Virulence Factors and the Formation of Biofilm in Pseudomonas aeruginosa PAO1.}, journal = {International journal of molecular sciences}, volume = {18}, number = {6}, pages = {}, pmid = {28613253}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Lamiaceae/*chemistry ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Quorum Sensing/*drug effects ; Terpenes/chemistry/isolation & purification/*pharmacology ; Virulence Factors/genetics ; }, abstract = {Platostoma rotundifolium (Briq.) A. J. Paton aerial parts are widely used in Burundi traditional medicine to treat infectious diseases. In order to investigate their probable antibacterial activities, crude extracts from P. rotundifolium were assessed for their bactericidal and anti-virulence properties against an opportunistic bacterial model, Pseudomonas aeruginosa PAO1. Whereas none of the tested extracts exert bacteriostatic and/or bactericidal proprieties, the ethyl acetate and dichloromethane extracts exhibit anti-virulence properties against Pseudomonas aeruginosa PAO1 characterized by an alteration in quorum sensing gene expression and biofilm formation without affecting bacterial viability. Bioguided fractionation of the ethyl acetate extract led to the isolation of major anti-virulence compounds that were identified from nuclear magnetic resonance and high-resolution molecular spectroscopy spectra as cassipourol, β-sitosterol and α-amyrin. Globally, cassipourol and β-sitosterol inhibit quorum sensing-regulated and -regulatory genes expression in las and rhl systems without affecting the global regulators gacA and vfr, whereas α-amyrin had no effect on the expression of these genes. These terpenoids disrupt the formation of biofilms at concentrations down to 12.5, 50 and 50 µM for cassipourol, β-sitosterol and α-amyrin, respectively. Moreover, these terpenoids reduce the production of total exopolysaccharides and promote flagella-dependent motilities (swimming and swarming). The isolated terpenoids exert a wide range of inhibition processes, suggesting a complex mechanism of action targeting P. aeruginosa virulence mechanisms which support the wide anti-infectious use of this plant species in traditional Burundian medicine.}, } @article {pmid28611763, year = {2017}, author = {Kim, TS and Ham, SY and Park, BB and Byun, Y and Park, HD}, title = {Lauroyl Arginate Ethyl Blocks the Iron Signals Necessary for Pseudomonas aeruginosa Biofilm Development.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {970}, pmid = {28611763}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium capable of forming a biofilm on living and non-living surfaces, which frequently leads to undesirable consequences. We found that lauroyl arginate ethyl (LAE), a synthetic non-oxidizing biocide, inhibited biofilm formation by P. aeruginosa at a sub-growth inhibitory concentration under both static and flow conditions. A global transcriptome analysis was conducted using a gene chip microarray to identify the genes targeted by LAE. In response to LAE treatment, P. aeruginosa cells up-regulated iron acquisition and signaling genes and down-regulated iron storage genes. LAE demonstrated the capacity to chelate iron in an experiment in which free LAE molecules were measured by increasing the ratio of iron to LAE. Furthermore, compared to untreated cells, P. aeruginosa cells treated with LAE exhibited enhanced twitching motility, a phenotype that is usually evident when the cells are starved for iron. Taken together, these results imply that LAE generated iron-limiting conditions, and in turn, blocked iron signals necessary for P. aeruginosa biofilm development. As destroying or blocking signals leading to biofilm development would be an efficient way to mitigate problematic biofilms, our findings suggest that LAE can aid in reducing P. aeruginosa biofilms for therapeutic and industrial purposes.}, } @article {pmid28611496, year = {2017}, author = {Ahiwale, SS and Bankar, AV and Tagunde, S and Kapadnis, BP}, title = {A Bacteriophage Mediated Gold Nanoparticles Synthesis and Their Anti-biofilm Activity.}, journal = {Indian journal of microbiology}, volume = {57}, number = {2}, pages = {188-194}, pmid = {28611496}, issn = {0046-8991}, abstract = {In the present study, gold nanoparticles (AuNPs) synthesis was carried out by using a rare bacteriophage which is morphologically similar to 7-11 phages of the C3 morphotype of tailed phage belonging to Podoviridae family as green route. Effect of various physiological parameters like pH, temperature and concentration of gold chloride salt on AuNPs synthesis was studied. The reaction mixtures have shown vivid colours at various physiological parameters. Phage inspired AuNPs were further characterized by using different techniques such as UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and dynamic light scattering (DLS). DLS study revealed synthesis of various sizes of AuNPs in the range of 20-100 nm. SEM studies revealed synthesis of varied shaped AuNPs, viz., spheres, hexagons, triangles, rhomboids and rectangular etc. The presence of Au in the nanostructures was confirmed by EDS. The XRD pattern reflects the crystalline nature and nano size of AuNPs. These phage inspired AuNPs showed anti-bacterial activity against different bacterial pathogens. Anti-biofilm activity of AuNPs was evaluated on a glass slide. It was noticed that at 0.2 mM concentration of these AuNPs about 80% of biofilm formation by Pseudomonas aeruginosa, a human pathogen was inhibited. Thus, the phage inspired AuNPs synthesis could be potential therapeutic agents against human pathogens.}, } @article {pmid28611429, year = {2017}, author = {Pan, Y and Song, S and Tang, X and Ai, Q and Zhu, D and Liu, Z and Yu, J}, title = {Streptococcus sp. in neonatal endotracheal tube biofilms is associated with ventilator-associated pneumonia and enhanced biofilm formation of Pseudomonas aeruginosa PAO1.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {3423}, pmid = {28611429}, issn = {2045-2322}, mesh = {*Biofilms ; Female ; Humans ; Infant, Newborn ; Interleukin-8/metabolism ; Male ; *Microbiota ; Pneumonia, Ventilator-Associated/*microbiology ; Pseudomonas aeruginosa/pathogenicity/*physiology ; Respiratory Mucosa/metabolism ; Streptococcus/pathogenicity/*physiology ; Ventilators, Mechanical/*microbiology ; }, abstract = {Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation leading to high morbidity and mortality among intubated neonates in neonatal intensive care units (NICUs). Endotracheal tube (ETT) biofilm flora were considered to be responsible for the occurrence of VAP as a reservoir of pathogens. However, regarding neonates with VAP, little is known about the complex microbial signatures in ETT biofilms. In the present study, a culture-independent approach based on next generation sequencing was performed as an initial survey to investigate the microbial communities in ETT biofilms of 49 intubated neonates with and without VAP. Our results revealed a far more complex microflora in ETT biofilms from intubated neonates compared to a previous culture-based study. The abundance of Streptococci in ETT biofilms was significantly related to the onset of VAP. By isolating Streptococci in ETT biofilms, we found that Streptococci enhanced biofilm formation of the common nosocomial pathogen Pseudomonas aeruginosa PAO1 and decreased IL-8 expression of airway epithelia cells exposed to the biofilm conditioned medium of PAO1. This study provides new insight into the pathogenesis of VAP among intubated neonates. More studies focusing on intubated neonates are warranted to develop strategies to address this important nosocomial disease in NICUs.}, } @article {pmid28610835, year = {2017}, author = {Dong, Y and Xu, Y and Li, P and Wang, C and Cao, Y and Yu, J}, title = {Antibiofilm effect of ultrasound combined with microbubbles against Staphylococcus epidermidis biofilm.}, journal = {International journal of medical microbiology : IJMM}, volume = {307}, number = {6}, pages = {321-328}, doi = {10.1016/j.ijmm.2017.06.001}, pmid = {28610835}, issn = {1618-0607}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Cell Membrane Permeability/drug effects ; Chemotaxis/drug effects ; Drug Resistance, Bacterial/drug effects ; Fluorescent Dyes/pharmacology ; Humans ; Microbubbles/*therapeutic use ; Neutrophils ; Phagocytosis/drug effects ; RNA, Bacterial/genetics/metabolism ; Rabbits ; Respiratory Burst/drug effects ; Sonication/*methods ; Staphylococcal Infections/*therapy ; Staphylococcus epidermidis/*drug effects ; Vancomycin/pharmacology ; }, abstract = {Biofilms are difficult to eradicate due to their resistance to antibiotics and host immune cells. Ultrasound microbubbles have emerged as a new treatment modality with the underlying mechanisms largely unknown. In this study, we exposed 24-h-old Staphylococcus epidermidis biofilms established in OptiCell™ chambers to ultrasound in combination with microbubbles, and investigated the activities of vancomycin and neutrophils against S. epidermidis biofilms after treatment. The antibiofilm mechanims of ultrasound microbubbles were explored in terms of bacterial permeability and biofilm-associated gene expression. After treatment of ultrasound (1MHz, 0.5W/cm[2], 50% duty cycle) combined with microbubbles in the concentration of 1% and 4% (v/v) for 5min, bacterial permeability to extracellular fluorescent dyes was enhanced and the expression of icaA was down-regulated while that of agrB and RNAIII up-regulated. Post-treatment biofilms were more sensitive to vancomycin by demonstrating reduced biomass than those exposed to vancomycin alone (P<0.05). The phagocytosis, oxidative burst activity as well as chemotaxis of neutrophils in response to biofilms were also significantly increased. The bioeffect of ultrasound combined with microbubbles was generally more significant than that of ultrasound alone, and dependent on microbubble concentration. This study demonstrated that ultrasound combined with microbubbles could enhance the activities of antibiotics and neutrophils against biofilms possibly via mechanical and biochemical mechanisms, and may provide an efficient and non-invasive antibiofilm alternative apart from chemical and biological approaches.}, } @article {pmid28608551, year = {2017}, author = {Sugino, H and Usui, T and Shimada, T and Nakano, M and Ogasawara, H and Ishihama, A and Hirata, A}, title = {A structural sketch of RcdA, a transcription factor controlling the master regulator of biofilm formation.}, journal = {FEBS letters}, volume = {591}, number = {13}, pages = {2019-2031}, doi = {10.1002/1873-3468.12713}, pmid = {28608551}, issn = {1873-3468}, mesh = {Biofilms/*growth & development ; DNA, Bacterial/chemistry/metabolism ; DNA-Binding Proteins/*chemistry/*metabolism ; Escherichia coli/metabolism/physiology ; Escherichia coli Proteins/*chemistry/*metabolism ; Models, Molecular ; Nucleic Acid Conformation ; Protein Conformation, alpha-Helical ; Transcription Factors/*chemistry/*metabolism ; }, abstract = {RcdA is a regulator of curlin subunit gene D, the master regulator of biofilm formation in Escherichia coli. Here, we determined the X-ray structure of RcdA at 2.55 Å resolution. RcdA consists of an N-terminal DNA-binding domain (DBD) containing a helix-turn-helix (HTH) motif and a C-terminal dimerization domain, and forms a homodimer in crystals. A computational docking model of the RcdA-DNA complex allowed prediction of the candidate residues responsible for DNA binding. Our structure-guided mutagenesis, in combination with gel shift assay, atomic force microscopic observation, and reporter assay, indicate that R32 in α2 of the HTH motif plays an essential role in the recognition and binding of target DNA while T46 in α3 influences the mode of oligomerization. These results provide insights into the DNA-binding mode of RcdA.}, } @article {pmid28607158, year = {2017}, author = {Teschler, JK and Cheng, AT and Yildiz, FH}, title = {The Two-Component Signal Transduction System VxrAB Positively Regulates Vibrio cholerae Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {199}, number = {18}, pages = {}, pmid = {28607158}, issn = {1098-5530}, support = {R01 AI055987/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; DNA Mutational Analysis ; Gene Deletion ; Histidine Kinase/genetics/*metabolism ; *Signal Transduction ; Transcription Factors/genetics/*metabolism ; Vibrio cholerae/*genetics/*physiology ; }, abstract = {Two-component signal transduction systems (TCSs), typically composed of a sensor histidine kinase (HK) and a response regulator (RR), are the primary mechanism by which pathogenic bacteria sense and respond to extracellular signals. The pathogenic bacterium Vibrio cholerae is no exception and harbors 52 RR genes. Using in-frame deletion mutants of each RR gene, we performed a systematic analysis of their role in V. cholerae biofilm formation. We determined that 7 RRs impacted the expression of an essential biofilm gene and found that the recently characterized RR, VxrB, regulates the expression of key structural and regulatory biofilm genes in V. choleraevxrB is part of a 5-gene operon, which contains the cognate HK vxrA and three genes of unknown function. Strains carrying ΔvxrA and ΔvxrB mutations are deficient in biofilm formation, while the ΔvxrC mutation enhances biofilm formation. The overexpression of VxrB led to a decrease in motility. We also observed a small but reproducible effect of the absence of VxrB on the levels of cyclic di-GMP (c-di-GMP). Our work reveals a new function for the Vxr TCS as a regulator of biofilm formation and suggests that this regulation may act through key biofilm regulators and the modulation of cellular c-di-GMP levels.IMPORTANCE Biofilms play an important role in the Vibrio cholerae life cycle, providing protection from environmental stresses and contributing to the transmission of V. cholerae to the human host. V. cholerae can utilize two-component systems (TCS), composed of a histidine kinase (HK) and a response regulator (RR), to regulate biofilm formation in response to external cues. We performed a systematic analysis of V. cholerae RRs and identified a new regulator of biofilm formation, VxrB. We demonstrated that the VxrAB TCS is essential for robust biofilm formation and that this system may regulate biofilm formation via its regulation of key biofilm regulators and cyclic di-GMP levels. This research furthers our understanding of the role that TCSs play in the regulation of V. cholerae biofilm formation.}, } @article {pmid28607050, year = {2017}, author = {Wang, Y and Cheng, LI and Helfer, DR and Ashbaugh, AG and Miller, RJ and Tzomides, AJ and Thompson, JM and Ortines, RV and Tsai, AS and Liu, H and Dillen, CA and Archer, NK and Cohen, TS and Tkaczyk, C and Stover, CK and Sellman, BR and Miller, LS}, title = {Mouse model of hematogenous implant-related Staphylococcus aureus biofilm infection reveals therapeutic targets.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {26}, pages = {E5094-E5102}, pmid = {28607050}, issn = {1091-6490}, support = {T32 AR067708/AR/NIAMS NIH HHS/United States ; }, mesh = {Animals ; Antibodies, Bacterial/*pharmacology ; Antibodies, Neutralizing/*pharmacology ; *Arthritis, Infectious/drug therapy/etiology/microbiology ; Biofilms/*drug effects ; Disease Models, Animal ; Humans ; Implants, Experimental/*microbiology ; Male ; Mice ; *Osteomyelitis/drug therapy/etiology/microbiology ; *Staphylococcal Infections/drug therapy/etiology/microbiology ; Staphylococcus aureus/*physiology ; Titanium ; }, abstract = {Infection is a major complication of implantable medical devices, which provide a scaffold for biofilm formation, thereby reducing susceptibility to antibiotics and complicating treatment. Hematogenous implant-related infections following bacteremia are particularly problematic because they can occur at any time in a previously stable implant. Herein, we developed a model of hematogenous infection in which an orthopedic titanium implant was surgically placed in the legs of mice followed 3 wk later by an i.v. exposure to Staphylococcus aureus This procedure resulted in a marked propensity for a hematogenous implant-related infection comprised of septic arthritis, osteomyelitis, and biofilm formation on the implants in the surgical legs compared with sham-operated surgical legs without implant placement and with contralateral nonoperated normal legs. Neutralizing human monoclonal antibodies against α-toxin (AT) and clumping factor A (ClfA), especially in combination, inhibited biofilm formation in vitro and the hematogenous implant-related infection in vivo. Our findings suggest that AT and ClfA are pathogenic factors that could be therapeutically targeted against Saureus hematogenous implant-related infections.}, } @article {pmid28605431, year = {2017}, author = {Maunders, E and Welch, M}, title = {Matrix exopolysaccharides; the sticky side of biofilm formation.}, journal = {FEMS microbiology letters}, volume = {364}, number = {13}, pages = {}, pmid = {28605431}, issn = {1574-6968}, support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Alginates/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Cystic Fibrosis/drug therapy/microbiology ; Drug Resistance, Bacterial/genetics ; Escherichia coli Proteins/metabolism ; Glucuronic Acid/genetics/metabolism ; Hexuronic Acids/metabolism ; Humans ; Phosphorus-Oxygen Lyases/metabolism ; Polysaccharides, Bacterial/genetics/*metabolism ; Pseudomonas aeruginosa/*physiology ; }, abstract = {The Gram-negative pathogen Pseudomonas aeruginosa is found ubiquitously within the environment and is recognised as an opportunistic human pathogen that commonly infects burn wounds and immunocompromised individuals, or patients suffering from the autosomal recessive disorder cystic fibrosis (CF). During chronic infection, P. aeruginosa is thought to form structured aggregates known as biofilms characterised by a self-produced matrix which encases the bacteria, protecting them from antimicrobial attack and the host immune response. In many cases, antibiotics are ineffective at eradicating P. aeruginosa from chronically infected CF airways. Cyclic-di-GMP has been identified as a key regulator of biofilm formation; however, the way in which its effector proteins elicit a change in biofilm formation remains unclear. Identifying regulators of biofilm formation is a key theme of current research and understanding the factors that activate biofilm formation may help to expose potential new drug targets that slow the onset of chronic infection. This minireview outlines the contribution made by exopolysaccharides to biofilm formation, and describes the current understanding of biofilm regulation in P. aeruginosa with a particular focus on CF airway-associated infections.}, } @article {pmid28605194, year = {2017}, author = {Hossain, S and Nisbett, LM and Boon, EM}, title = {Discovery of Two Bacterial Nitric Oxide-Responsive Proteins and Their Roles in Bacterial Biofilm Regulation.}, journal = {Accounts of chemical research}, volume = {50}, number = {7}, pages = {1633-1639}, pmid = {28605194}, issn = {1520-4898}, support = {R01 GM118894/GM/NIGMS NIH HHS/United States ; T32 GM092714/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacteria/*metabolism ; Bacterial Proteins/*metabolism ; *Biofilms ; Nitric Oxide/*metabolism ; }, abstract = {Bacterial biofilms form when bacteria adhere to a surface and produce an exopolysaccharide matrix (Costerton Science 1999 , 284 , 1318 ; Davies Science 1998 , 280 , 295 ; Flemming Nat. Rev. Microbiol. 2010 , 8 , 623). Because biofilms are resistant to antibiotics, they are problematic in many aspects of human health and welfare, causing, for instance, persistent fouling of medical implants such as catheters and artificial joints (Brunetto Chimia 2008 , 62 , 249). They are responsible for chronic infections in the lungs of cystic fibrosis patients and in open wounds, such as those associated with burns and diabetes. They are also a major contributor to hospital-acquired infections (Sievert Infec. Control Hosp. Epidemiol. 2013 , 34 , 1 ; Tatterson Front. Biosci. 2001 , 6 , D890). It has been hypothesized that effective methods of biofilm control will have widespread application (Landini Appl. Microbiol. Biotechnol. 2010 , 86 , 813). A promising strategy is to target the mechanisms that drive biofilm dispersal, because dispersal results in biofilm removal and in the restoration of antibiotic sensitivity. First documented in Nitrosomonas europaea (Schmidt J. Bacteriol. 2004 , 186 , 2781) and the cystic fibrosis-associated pathogen Pseudomonas aeruginosa (Barraud J. Bacteriol. 2006 , 188 , 7344 ; J. Bacteriol. 2009 , 191 , 7333), regulation of biofilm formation by nanomolar levels of the diatomic gas nitric oxide (NO) has now been documented in numerous bacteria (Barraud Microb. Biotechnol. 2009 , 2 , 370 ; McDougald Nat. Rev. Microbiol. 2012 , 10 , 39 ; Arora Biochemistry 2015 , 54 , 3717 ; Barraud Curr. Pharm. Des. 2015 , 21 , 31). NO-mediated pathways are, therefore, promising candidates for biofilm regulation. Characterization of the NO sensors and NO-regulated signaling pathways should allow for rational manipulation of these pathways for therapeutic applications. Several laboratories, including our own, have shown that a class of NO sensors called H-NOX (heme-nitric oxide or oxygen binding domain) affects biofilm formation by regulating intracellular cyclic di-GMP concentrations and quorum sensing (Arora Biochemistry 2015 , 54 , 3717 ; Plate Trends Biochem. Sci. 2013 , 38 , 566 ; Nisbett Biochemistry 2016 , 55 , 4873). Many bacteria that respond to NO do not encode an hnoX gene, however. My laboratory has now discovered an additional family of bacterial NO sensors, called NosP (nitric oxide sensing protein). Importantly, NosP domains are widely conserved in bacteria, especially Gram-negative bacteria, where they are encoded as fusions with or in close chromosomal proximity to histidine kinases or cyclic di-GMP synthesis or phosphodiesterase enzyme, consistent with signaling. In this Account, we briefly review NO and H-NOX signaling in bacterial biofilms, describe our discovery of the NosP family, and provide support for its role in biofilm regulation in Pseudomonas aeruginosa, Vibrio cholerae, Legionella pneumophila, and Shewanella oneidensis.}, } @article {pmid28604167, year = {2017}, author = {Cusick, KD and Dale, JR and Fitzgerald, LA and Little, BJ and Biffinger, JC}, title = {Adaptation to copper stress influences biofilm formation in Alteromonas macleodii.}, journal = {Biofouling}, volume = {33}, number = {6}, pages = {505-519}, doi = {10.1080/08927014.2017.1329423}, pmid = {28604167}, issn = {1029-2454}, mesh = {Alteromonas/*drug effects/genetics ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Copper/analysis/*pharmacology ; Cyclic GMP/analogs & derivatives/biosynthesis ; Disinfectants/analysis/*pharmacology ; Drug Resistance, Bacterial/*drug effects/genetics ; Escherichia coli Proteins/genetics ; *Genes, Bacterial ; Models, Theoretical ; Mutation ; Phosphorus-Oxygen Lyases/genetics ; Seawater/chemistry ; }, abstract = {An Alteromonas macleodii strain was isolated from copper-containing coupons incubated in surface seawater (Key West, FL, USA). In addition to the original isolate, a copper-adapted mutant was created and maintained with 0.78 mM Cu[2+]. Biofilm formation was compared between the two strains under copper-amended and low-nutrient conditions. Biofilm formation was significantly increased in the original isolate under copper amendment, while biofilm formation was significantly higher in the mutant under low-nutrient conditions. Biofilm expression profiles of diguanylate cyclase (DGC) genes, as well as genes involved in secretion, differed between the strains. Comparative genomic analysis demonstrated that both strains possessed a large number of gene attachment harboring cyclic di-GMP synthesis and/or degradation domains. One of the DGC genes, induced at very high levels in the mutant, possessed a degradation domain in the original isolate that was lacking in the mutant. The genetic and transcriptional mechanisms contributing to biofilm formation are discussed.}, } @article {pmid28603699, year = {2017}, author = {Zuberi, A and Misba, L and Khan, AU}, title = {CRISPR Interference (CRISPRi) Inhibition of luxS Gene Expression in E. coli: An Approach to Inhibit Biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {214}, pmid = {28603699}, issn = {2235-2988}, mesh = {Bacterial Proteins/*genetics/*metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/*genetics/*metabolism ; *Clustered Regularly Interspaced Short Palindromic Repeats ; Escherichia coli/*genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Gene Knockdown Techniques ; Genetic Complementation Test ; Homoserine/analogs & derivatives/metabolism ; Humans ; Lactones/metabolism ; Microbial Viability ; Microscopy, Electron, Scanning ; Quorum Sensing ; }, abstract = {Biofilm is a sessile bacterial accretion embedded in self-producing matrix. It is the root cause of about 80% microbial infections in human. Among them, E. coli biofilms are most prevalent in medical devices associated nosocomial infections. The objective of this study was to inhibit biofilm formation by targeting gene involved in quorum sensing, one of the main mechanisms of biofilm formation. Hence we have introduced the CRISPRi, first time to target luxS gene. luxS is a synthase, involved in the synthesis of Autoinducer-2(AI-2), which in turn guides the initial stage of biofilm formation. To implement CRISPRi system for luxS gene suppression, we have synthesized complementary sgRNA to target gene sequence and co-expressed with dCas9, a mutated form of an endonuclease. Suppression of luxS expression was confirmed through qRT-PCR. The effect of luxS gene on biofilm inhibition was studied through crystal violet assay, XTT reduction assay and scanning electron microscopy. We conclude that CRISPRi system could be a potential strategy to inhibit bacterial biofilm through mechanism base approach.}, } @article {pmid28602213, year = {2017}, author = {Ardesia, M and Mondello, P and Fries, W}, title = {Biofilm-producing fungi as emergent cause of bloodstream infections in patients with inflammatory bowel disease.}, journal = {Medicina clinica}, volume = {149}, number = {6}, pages = {272-273}, doi = {10.1016/j.medcli.2017.04.021}, pmid = {28602213}, issn = {1578-8989}, mesh = {Anti-Bacterial Agents ; Bacteremia ; *Biofilms ; *Catheter-Related Infections ; Fungi ; Humans ; Inflammatory Bowel Diseases ; }, } @article {pmid28599174, year = {2017}, author = {Nowak, J and Cruz, CD and Tempelaars, M and Abee, T and van Vliet, AHM and Fletcher, GC and Hedderley, D and Palmer, J and Flint, S}, title = {Persistent Listeria monocytogenes strains isolated from mussel production facilities form more biofilm but are not linked to specific genetic markers.}, journal = {International journal of food microbiology}, volume = {256}, number = {}, pages = {45-53}, doi = {10.1016/j.ijfoodmicro.2017.05.024}, pmid = {28599174}, issn = {1879-3460}, mesh = {Animals ; Base Sequence ; Biofilms/*growth & development ; Bivalvia/*microbiology ; DNA, Bacterial/genetics ; *Food Handling ; Genetic Markers/genetics ; Genome, Bacterial/genetics ; Genotype ; Hot Temperature ; Humans ; *Listeria monocytogenes/genetics/isolation & purification/metabolism ; Multilocus Sequence Typing ; New Zealand ; Phenotype ; Prophages/genetics ; Sequence Analysis, DNA ; }, abstract = {Contamination of mussels with the human pathogen Listeria monocytogenes occurs during processing in the factory, possibly from bacteria persisting in the factory's indoor and outdoor areas. In this study, a selection of persistent (n=8) and sporadic (n=8) L. monocytogenes isolates associated with mussel-processing premises in New Zealand were investigated for their phenotypic and genomic characteristics. To identify traits that favour or contribute to bacterial persistence, biofilm formation, heat resistance, motility and recovery from dry surfaces were compared between persistent and sporadic isolates. All isolates exhibited low biofilm formation at 20°C, however, at 30°C persistent isolates showed significantly higher biofilm formation after 48h using cell enumeration and near significant difference using the crystal violet assay. All 16 isolates were motile at 20°C and 30°C and motility was fractionally higher for sporadic isolates, but no significant difference was observed. We found persistent isolates tend to exhibit greater recovery after incubation on dry surfaces compared to sporadic isolates. Two of the three most heat-resistant isolates were persistent, while four of five isolates lacking heat resistance were sporadic isolates. Comparison of genome sequences of persistent and sporadic isolates showed that there was no overall clustering of persistent or sporadic isolates, and that differences in prophages and plasmids were not associated with persistence. Our results suggest a link between persistence and biofilm formation, which is most likely multifactorial, combining subtle phenotypic and genotypic differences between isolates.}, } @article {pmid28598310, year = {2017}, author = {Hashem, AA and Abd El Fadeal, NM and Shehata, AS}, title = {In vitro activities of vancomycin and linezolid against biofilm-producing methicillin-resistant staphylococci species isolated from catheter-related bloodstream infections from an Egyptian tertiary hospital.}, journal = {Journal of medical microbiology}, volume = {66}, number = {6}, pages = {744-752}, doi = {10.1099/jmm.0.000490}, pmid = {28598310}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteremia/etiology/microbiology ; Bacterial Proteins/genetics ; Biofilms/drug effects/growth & development ; Catheter-Related Infections/*microbiology ; Catheters/microbiology ; Drug Resistance, Bacterial ; Egypt/epidemiology ; Humans ; Linezolid/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification/physiology ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins/genetics ; Polymerase Chain Reaction ; Rifampin/pharmacology ; Staphylococcal Infections/epidemiology/*microbiology ; Staphylococcus/classification/drug effects/isolation & purification ; Staphylococcus aureus/drug effects ; Tertiary Care Centers ; Vancomycin/*pharmacology ; }, abstract = {PURPOSE: Catheter-related bloodstream infections (CRBSIs) are among the most common hospital-acquired infections. We aimed to survey methicillin resistance, biofilm production and susceptibility to vancomycin, linezolid and other antibiotics for staphylococci isolated from CRBSIs.

METHODOLOGY: Fifty-eight isolates [20 S. aureus and 38 coagulase-negative staphylococci (CoNS; 20 Staphylococcusepidermidis, nine Staphylococcushaemolyticus, three Staphylococcusschleiferi, two Staphylococcuswarneri and four Staphylococcuslugdunensis)] were tested for methicillin resistance by cefoxitin disk diffusion and detection of the mecA gene by PCR; biofilm-forming ability using Congo red agar and tissue culture plate methods; susceptibility to ciprofloxacin, clindamycin, cotrimoxazole, erythromycin, gentamicin, linezolid, rifampicin and tetracycline; and MIC determination for vancomycin.Results/Key findings. Cefoxitin resistance was detected among 40 % (8/20) S. aureus isolates, 70 % (14/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS, although the mecA gene was detected in 45 % (9/20) S. aureus isolates, 35 % (7/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS. Biofilm-forming ability ranged from 45 to 75 %. Methicillin-resistant S. aureus and other CoNS were considered to be more virulent than methicillin-resistant S. epidermidis due to the higher biofilm forming abilities of the former. All tested isolates exhibited 100 % sensitivity to vancomycin and linezolid, irrespective of their methicillin resistance or biofilm-forming ability. Rifampicin showed overall sensitivity of 75.9 %. Varying degrees of multi-resistance were found for the other antibiotics.

CONCLUSION: Vancomycin, linezolid and rifampicin could be used effectively against methicillin-resistant staphylococci isolated from CRBSIs.}, } @article {pmid28598304, year = {2017}, author = {Sardi, JCO and Polaquini, CR and Freires, IA and Galvão, LCC and Lazarini, JG and Torrezan, GS and Regasini, LO and Rosalen, PL}, title = {Antibacterial activity of diacetylcurcumin against Staphylococcus aureus results in decreased biofilm and cellular adhesion.}, journal = {Journal of medical microbiology}, volume = {66}, number = {6}, pages = {816-824}, doi = {10.1099/jmm.0.000494}, pmid = {28598304}, issn = {1473-5644}, mesh = {Adhesins, Bacterial/*drug effects ; Animals ; Anti-Bacterial Agents/administration & dosage/adverse effects/*pharmacology ; Biofilms/*drug effects/growth & development ; Curcumin/administration & dosage/adverse effects/*analogs & derivatives/pharmacology ; Humans ; Keratinocytes/drug effects/microbiology ; Larva/drug effects/microbiology ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Moths/drug effects/microbiology ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {PURPOSE: Staphylococcus aureus infections have contributed to the global healthcare burden, particularly with regard to hospital-acquired meticillin-resistant S. aureus (MRSA) infections.

METHODOLOGY: This study describes the antibacterial activity of diacetylcurcumin (DAC) against meticillin-susceptible S. aureus/MRSA biofilm formation, survival, metabolic activity and structure; its ability to prevent bacterial adhesion to human cells; and toxicity in Galleria mellonella larvae.

RESULTS: DAC showed excellent antibacterial activity, with MIC ranging between 17.3 and 34.6 µmol l-1, and minimum bactericidal concentration ranging between 69 and 277 µmol l-1. It significantly reduced bacterial biofilm survival - by 22-63 % (at MIC, 10×MIC or 100×MIC) as compared to the 25-42 % reduction by vancomycin (P<0.0001) - and severely affected biofilm cell structures, leading to damaged architecture and the formation of amorphous cell clusters. Treatment with DAC (MIC/4) decreased bacterial adhesion to HaCaT keratinocytes from 1 to 5 h (P<0.0001). Finally, DAC demonstrated low toxicity in G. mellonella at its effective anti-biofilm concentrations.

CONCLUSION: These findings open new avenues for the study of this curcumin derivative as an excellent prototype with anti-MRSA activity.}, } @article {pmid28598149, year = {2017}, author = {Richter, K and Facal, P and Thomas, N and Vandecandelaere, I and Ramezanpour, M and Cooksley, C and Prestidge, CA and Coenye, T and Wormald, PJ and Vreugde, S}, title = {Taking the Silver Bullet Colloidal Silver Particles for the Topical Treatment of Biofilm-Related Infections.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {26}, pages = {21631-21638}, doi = {10.1021/acsami.7b03672}, pmid = {28598149}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Caenorhabditis elegans ; Metal Nanoparticles ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; Silver ; }, abstract = {Biofilms are aggregates of bacteria residing in a self-assembled matrix, which protects these sessile cells against external stress, including antibiotic therapies. In light of emerging multidrug-resistant bacteria, alternative strategies to antibiotics are emerging. The present study evaluated the activity of colloidal silver nanoparticles (AgNPs) of different shapes against biofilms formed by Staphylococcus aureus (SA), methicillin-resistant SA (MRSA), and Pseudomonas aeruginosa (PA). Colloidal quasi-spherical, cubic, and star-shaped AgNPs were synthesized, and their cytotoxicity on macrophages (THP-1) and bronchial epithelial cells (Nuli-1) was analyzed by the lactate dehydrogenase assay. The antibiofilm activity was assessed in vitro by the resazurin assay and in an in vivo infection model in Caenorhabditis elegans. Cubic and star-shaped AgNPs induced cytotoxicity, while quasi-spherical AgNPs were not toxic. Quasi-spherical AgNPs showed substantial antibiofilm activity in vitro with 96% (±2%), 97% (±1%), and 98% (±1%) biofilm killing of SA, MRSA, and PA, respectively, while significantly reducing mortality of infected nematodes. The in vivo antibiofilm activity was linked to the accumulation of AgNPs in the intestinal tract of C. elegans as observed by 3D X-ray tomography. Quasi-spherical AgNPs were physically stable in suspension for over 6 months with no observed loss in antibiofilm activity. While toxicity and stability limited the utilization of cubic and star-shaped AgNPs, quasi-spherical AgNPs could be rapidly synthesized, were stable and nontoxic, and showed substantial in vitro and in vivo activity against clinically relevant biofilms. Quasi-spherical AgNPs hold potential as pharmacotherapy, for example, as topical treatment for biofilm-related infections.}, } @article {pmid28595913, year = {2018}, author = {di Biase, A and Devlin, TR and Kowalski, MS and Oleszkiewicz, JA}, title = {Performance and design considerations for an anaerobic moving bed biofilm reactor treating brewery wastewater: Impact of surface area loading rate and temperature.}, journal = {Journal of environmental management}, volume = {216}, number = {}, pages = {392-398}, doi = {10.1016/j.jenvman.2017.05.093}, pmid = {28595913}, issn = {1095-8630}, mesh = {Anaerobiosis ; *Biofilms ; Bioreactors ; Temperature ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Three 4 L anaerobic moving bed biofilm reactors (AMBBR) treated brewery wastewater with AC920 media providing 680 m[2] protected surface area per m[3] of media. Different hydraulic retention times (HRT; 24, 18, 12, 10, 8 and 6 h) at 40% media fill and 35 °C, as well as different temperatures (15, 25 and 35 °C) at 50% media fill and 18 h HRT were examined. Best performance at 35 °C and 40% media fill was observed when HRT was 18 h, which corresponded with 92% removal of soluble COD (sCOD). Organic loading rates (OLR) above 24 kg-COD m[-3]d[-1] decreased performance below 80% sCOD removal at 35 °C and 40% media fill. The reason was confirmed to be that surface area loading rates (SALR) above 50 g-sCOD m[-2]d[-1] caused excessive biofilm thickness that filled up internal channels of the media, leading to mass transfer limitations. Temperature had a very significant impact on process performance with 50% media fill and 18 h HRT. Biomass concentrations were significantly higher at lower temperatures. At 15 °C the mass of volatile solids (VS) was more than three times higher than at 35 °C for the same OLR. Biofilms acclimated to 25 °C and 15 °C achieved removal of 80% sCOD at SALR of 10 g-sCOD m[-2]d[-1] and 1.0 g-sCOD m[-2]d[-1], respectively. Even though biomass concentrations were higher at lower temperature, biofilm acclimated to 25 °C and 15 °C performed significantly slower than that acclimated to 35 °C.}, } @article {pmid28595324, year = {2017}, author = {de Ornellas Dutka Garcia, KC and de Oliveira Corrêa, IM and Pereira, LQ and Silva, TM and de Souza Ribeiro Mioni, M and de Moraes Izidoro, AC and Vellano Bastos, IH and Marietto Gonçalves, GA and Okamoto, AS and Andreatti Filho, RL}, title = {Bacteriophage use to control Salmonella biofilm on surfaces present in chicken slaughterhouses.}, journal = {Poultry science}, volume = {96}, number = {9}, pages = {3392-3398}, doi = {10.3382/ps/pex124}, pmid = {28595324}, issn = {1525-3171}, mesh = {Abattoirs ; Animals ; *Bacterial Adhesion ; Bacteriophages/*physiology ; *Biofilms ; Chickens ; Food Microbiology/*methods ; Glass ; Polyvinyl Chloride ; Salmonella/*physiology ; Stainless Steel ; }, abstract = {Foodborne diseases represent a major risk to public health worldwide. Pathogenic bacteria can live in the form of biofilm within the food industry, providing a permanent source of contamination. The aim of this study was to evaluate the influence of the types of adhesion surfaces on Salmonella biofilm formation at eight different times, and analyze the action time of a bacteriophage pool on established biofilms. Most of the samples used were classified as weak biofilm producers, with serovars Enteritidis and Heidelberg showing the highest frequency of biofilm formation. Glass and stainless steel surfaces significantly favored biofilm formation at 60 and 36 h of incubation respectively, but the polyvinyl chloride surface did not favor biofilm production, suggesting that the type of material may interfere with production. The bacteriophage pool action period focused on 3 h, but treatment of 9 h on glass surface biofilms was superior to other treatments because it affected the largest number of samples. These results suggests that some surface types and Salmonella serotypes may promote biofilm formation and indicate bacteriophages as an alternative to control biofilms. But further studies are required to prove the effectiveness and safety of bacteriophage therapy as an alternative in the antimicrobial control in the processing plants.}, } @article {pmid28594946, year = {2017}, author = {Hardy, L and Jespers, V and De Baetselier, I and Buyze, J and Mwambarangwe, L and Musengamana, V and van de Wijgert, J and Crucitti, T}, title = {Association of vaginal dysbiosis and biofilm with contraceptive vaginal ring biomass in African women.}, journal = {PloS one}, volume = {12}, number = {6}, pages = {e0178324}, pmid = {28594946}, issn = {1932-6203}, mesh = {Adult ; Africa ; Biofilms/*growth & development ; Biomass ; *Contraceptive Devices, Female ; Dysbiosis/*microbiology ; Female ; Gardnerella vaginalis/pathogenicity ; Humans ; Microbiota/physiology ; Microscopy, Electron, Scanning ; Vagina/*microbiology ; }, abstract = {We investigated the presence, density and bacterial composition of contraceptive vaginal ring biomass and its association with the vaginal microbiome. Of 415 rings worn by 120 Rwandese women for three weeks, the biomass density was assessed with crystal violet and the bacterial composition of biomass eluates was assessed with quantitative polymerase chain reaction (qPCR). The biomass was visualised after fluorescence in situ hybridisation (FISH) and with scanning electron microscopy (SEM). The vaginal microbiome was assessed with Nugent scoring and vaginal biofilm was visualised after FISH. All vaginal rings were covered with biomass (mean optical density (OD) of 3.36; standard deviation (SD) 0.64). Lactobacilli were present on 93% of the rings, Gardnerella vaginalis on 57%, and Atopobium vaginae on 37%. The ring biomass density was associated with the concentration of A. vaginae (OD +0.03; 95% confidence interval (CI) 0.01-0.05 for one log increase; p = 0.002) and of G. vaginalis (OD +0.03; (95% CI 0.01-0.05; p = 0.013). The density also correlated with Nugent score: rings worn by women with a BV Nugent score (mean OD +0.26), and intermediate score (mean OD +0.09) had a denser biomass compared to rings worn by participants with a normal score (p = 0.002). Furthermore, presence of vaginal biofilm containing G. vaginalis (p = 0.001) and A. vaginae (p = 0.005) correlated with a denser ring biomass (mean OD +0.24 and +0.22 respectively). With SEM we observed either a loose network of elongated bacteria or a dense biofilm. We found a correlation between vaginal dysbiosis and the density and composition of the ring biomass, and further research is needed to determine if these relationships are causal. As multipurpose vaginal rings to prevent pregnancy, HIV, and other sexually transmitted diseases are being developed, the potential impact of ring biomass on the vaginal microbiota and the release of active pharmaceutical ingredients should be researched in depth.}, } @article {pmid28592933, year = {2017}, author = {Asati, S and Chaudhary, U}, title = {Prevalence of biofilm producing aerobic bacterial isolates in burn wound infections at a tertiary care hospital in northern India.}, journal = {Annals of burns and fire disasters}, volume = {30}, number = {1}, pages = {39-42}, pmid = {28592933}, issn = {1592-9558}, abstract = {Burn wounds frequently get infected due to a break in skin integrity and prolonged hospitalization. Microbial flora originating from the patient's own flora colonize and infect the burn wounds. Bacterial biofilms in particular are postulated as the culprit for the development of non-healing burn wounds by inducing chronic inflammation in these patients. In the present study, 190 wound isolates obtained from patients admitted to the burn ward at the Pt. B.D. Sharma PGIMS, Rohtak, were evaluated for biofilm formation along with Antimicrobial Susceptibility Testing (AST). Biofilm detection was done by modified Tissue Culture Plate method and AST was done by Kirby-Bauer disc diffusion method. A total of 190 isolates were studied, which included Staphylococcus aureus, Coagulase negative Staphylococcus, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella spp., Proteus spp., Citrobacter spp., Escherichia coli and Enterobacter spp. Of these, 68.9% isolates showed biofilm formation. Biofilm formation was more common in Pseudomonas aeruginosa followed by Klebsiella spp. and Staphylococcus aureus. Biofilm producing isolates showed greater multidrug resistance than non-biofilm producers. In our study, a high rate of biofilm formation and antimicrobial drug resistance was seen.}, } @article {pmid28591237, year = {2017}, author = {Souza, LCD and Mota, VBRD and Carvalho, AVDSZ and Corrêa, RDGCF and Libério, SA and Lopes, FF}, title = {Association between pathogens from tracheal aspirate and oral biofilm of patients on mechanical ventilation.}, journal = {Brazilian oral research}, volume = {31}, number = {}, pages = {e38}, doi = {10.1590/1807-3107BOR-2017.vol31.0038}, pmid = {28591237}, issn = {1807-3107}, mesh = {Bacteria/*isolation & purification ; *Biofilms ; Candida albicans/isolation & purification ; Dental Plaque/microbiology ; Equipment Contamination ; Female ; Humans ; Intensive Care Units ; Intubation, Intratracheal/adverse effects ; Longitudinal Studies ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Mouth/*microbiology ; Pneumonia, Aspiration/microbiology ; Pneumonia, Ventilator-Associated/*microbiology ; Respiration, Artificial/adverse effects ; Time Factors ; Trachea/*microbiology ; Ventilators, Mechanical/*microbiology ; }, abstract = {The aim of this study was to detect possible associations between respiratory pathogens from tracheal aspirate and oral biofilm samples in intubated patients in an intensive care unit (ICU), and to identify the most common respiratory pathogens in oral biofilm, particularly in patients that developed ventilator-associated pneumonia (VAP). Two oral biofilm samples were collected from the tongue of intubated patients (at admission and after 48 hours) and analyzed by culture with the Antibiotic Sensitivity Test. The results from the tongue biofilm samples were compared with the tracheal secretions samples. A total of 59.37% of patients exhibited the same species of pathogens in their tracheal aspirate and oral biofilm, of which 8 (42.1%) developed VAP, 10 (52.63%) did not develop pneumonia and one (5.26%) had aspiration pneumonia. There was a statistically significant association between presence of microorganisms in the tracheal and mouth samples for the following pathogens: Klebsiella pneumoniae, Candida albicans, Pseudomonas aeruginosa, Enterobacter gergoviae, Streptococcus spp and Serratia marcescens (p < 0.05). Pathogens that are present in tracheal aspirates of intubated patients can be detected in their oral cavity, especially in those who developed VAP or aspiration pneumonia. Thus, the results indicate that an improved oral care in these patients could decrease ICU pneumonia rates.}, } @article {pmid28588567, year = {2017}, author = {Lerch, TZ and Chenu, C and Dignac, MF and Barriuso, E and Mariotti, A}, title = {Biofilm vs. Planktonic Lifestyle: Consequences for Pesticide 2,4-D Metabolism by Cupriavidus necator JMP134.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {904}, pmid = {28588567}, issn = {1664-302X}, abstract = {The development of bacterial biofilms in natural environments may alter important functions, such as pollutant bioremediation by modifying both the degraders' physiology and/or interactions within the matrix. The present study focuses on the influence of biofilm formation on the metabolism of a pesticide, 2,4-dichlorophenoxyacetic acid (2,4-D), by Cupriavidus necator JMP134. Pure cultures were established in a liquid medium with 2,4-D as a sole carbon source with or without sand grains for 10 days. Bacterial numbers and 2,4-D concentrations in solution were followed by spectrophotometry, the respiration rate by gas chromatography and the surface colonization by electron microscopy. In addition, isotopic techniques coupled with Fatty Acid Methyl Ester (FAME) profiling were used to determine possible metabolic changes. After only 3 days, approximately 80% of the cells were attached to the sand grains and microscopy images showed that the porous medium was totally clogged by the development of a biofilm. After 10 days, there was 25% less 2,4-D in the solution in samples with sand than in control samples. This difference was due to (1) a higher (+8%) mineralization of 2,4-D by sessile bacteria and (2) a retention (15%) of 2,4-D in the biofilm matrix. Besides, the amount of carbohydrates, presumably constituting the biofilm polysaccharides, increased by 63%. Compound-specific isotope analysis revealed that the FAME isotopic signature was less affected by the biofilm lifestyle than was the FAME composition. These results suggest that sessile bacteria differ more in their anabolism than in their catabolism compared to their planktonic counterparts. This study stresses the importance of considering interactions between microorganisms and their habitat when studying pollutant dynamics in porous media.}, } @article {pmid28587857, year = {2017}, author = {Alonso, B and Cruces, R and Pérez, A and Sánchez-Carrillo, C and Guembe, M}, title = {Comparison of the XTT and resazurin assays for quantification of the metabolic activity of Staphylococcus aureus biofilm.}, journal = {Journal of microbiological methods}, volume = {139}, number = {}, pages = {135-137}, doi = {10.1016/j.mimet.2017.06.004}, pmid = {28587857}, issn = {1872-8359}, mesh = {Biofilms/growth & development ; Formazans/analysis ; *Oxazines/analysis ; Staining and Labeling ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*metabolism ; Tetrazolium Salts/*pharmacology ; *Xanthenes ; }, abstract = {We assessed whether resazurin was as efficient as XTT in the measurement of the metabolic activity of 209 clinical Staphylococcus aureus biofilm using an vitro model comparing the percentage of formazan and resorufin. The overall categorical agreement was 61.2% (r=0.024), which means that resazurin can not substitute XTT.}, } @article {pmid28587519, year = {2017}, author = {Liu, J and Zhang, J and Guo, L and Zhao, W and Hu, X and Wei, X}, title = {Inactivation of a putative efflux pump (LmrB) in Streptococcus mutans results in altered biofilm structure and increased exopolysaccharide synthesis: implications for biofilm resistance.}, journal = {Biofouling}, volume = {33}, number = {6}, pages = {481-493}, doi = {10.1080/08927014.2017.1323206}, pmid = {28587519}, issn = {1029-2454}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Dental Caries/microbiology ; Drug Resistance, Bacterial/*genetics ; Gene Expression/*drug effects ; *Genes, Bacterial ; Ion Pumps/genetics ; Microscopy, Confocal ; Mutation ; Polysaccharides, Bacterial/*biosynthesis ; Streptococcus mutans/*drug effects/genetics/physiology ; }, abstract = {Efflux pumps are a mechanism associated with biofilm formation and resistance. There is limited information regarding efflux pumps in Streptococcus mutans, a major pathogen in dental caries. The aim of this study was to investigate potential roles of a putative efflux pump (LmrB) in S. mutans biofilm formation and susceptibility. Upon lmrB inactivation and antimicrobial exposure, the biofilm structure and expression of other efflux pumps were examined using confocal laser scanning microscopy (CLSM) and qRT-PCR. lmrB inactivation resulted in biofilm structural changes, increased EPS formation and EPS-related gene transcription (p < 0.05), but no improvement in susceptibility was observed. The expression of most efflux pump genes increased upon lmrB inactivation when exposed to antimicrobials (p < 0.05), suggesting a feedback mechanism that activated the transcription of other efflux pumps to compensate for the loss of lmrB. These observations imply that sole inactivation of lmrB is not an effective solution to control biofilms.}, } @article {pmid28587324, year = {2017}, author = {Kong, JL and Luo, J and Li, B and Dong, BY and Huang, H and Wang, K and Wu, LH and Chen, YQ}, title = {In vitro activity of chlorogenic acid against Aspergillus fumigatus biofilm and gliotoxin production.}, journal = {Experimental and therapeutic medicine}, volume = {13}, number = {6}, pages = {2637-2644}, pmid = {28587324}, issn = {1792-0981}, abstract = {Aspergillus (A.) fumigatus, one of the most common causes of life-threatening fungal infections in immunocompromised patients, shows resistance to antifungal agents as has a high propensity to forming a biofilm. The present study aimed to investigate the effects of chlorogenic acid (CRA) on A. fumigatus biofilm formation and integrity. Confocal laser scanning microscopy was performed to determine the inhibitory effects of CRA against A. fumigatus biofilm formation. Transmission electron microscopy was performed to investigate the ultrastructural changes of A. fumigatus biofilm after CRA exposure. High-performance liquid chromatography and reverse-transcription quantitative PCR were performed to determine the expression of gliotoxin production in biofilm culture. The results showed that CRA at sub-minimum inhibitory concentrations inhibited A. fumigatus biofilm formation. In addition, CRA could decreased the gliotoxin production in the biofilm culture supernatant through inhibiting the expression of master genes involved in gliotoxin biosynthesis. The present study provided useful information for the development of novel strategies to reduce the incidence of A. fumigatus biofilm-associated diseases.}, } @article {pmid28586050, year = {2017}, author = {Kacergius, T and Abu-Lafi, S and Kirkliauskiene, A and Gabe, V and Adawi, A and Rayan, M and Qutob, M and Stukas, R and Utkus, A and Zeidan, M and Rayan, A}, title = {Inhibitory capacity of Rhus coriaria L. extract and its major component methyl gallate on Streptococcus mutans biofilm formation by optical profilometry: Potential applications for oral health.}, journal = {Molecular medicine reports}, volume = {16}, number = {1}, pages = {949-956}, doi = {10.3892/mmr.2017.6674}, pmid = {28586050}, issn = {1791-3004}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Gallic Acid/analogs & derivatives/chemistry/pharmacology ; Humans ; Hydrogen-Ion Concentration ; Molecular Structure ; Oral Health ; Phytochemicals/chemistry/pharmacology ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Rhus/*chemistry ; Spectrum Analysis ; Streptococcus mutans/*drug effects/*growth & development ; }, abstract = {Streptococcus mutans (S. mutans) bacterium is the most well recognized pathogen involved in pathogenesis of dental caries. Its virulence arises from its ability to produce a biofilm and acidogenicity, causing tooth decay. Discovery of natural products capable to inhibit biofilm formation is of high importance for developing health care products. To the best of our knowledge, in all previous scientific reports, a colorimetric assay was applied to test the effect of sumac and methyl gallate (MG) on S. mutans adherence. Quantitative assessment of the developed biofilm should be further performed by applying an optical profilometry assay, and by testing the effect on both surface roughness and thickness parameters of the biofilm. To the best of our knowledge, this is the first study to report the effect of sumac extract and its constituent MG on biofilm formation using an optical profilometry assay. Testing antibacterial activity of the sumac extract and its fractions revealed that MG is the most bioactive component against S. mutans bacteria. It reduced S. mutans biofilm biomass on the polystyrene surface by 68‑93%, whereas 1 mg/ml MG was able to decrease the biofilm roughness and thickness on the glass surface by 99%. MG also prevented a decrease in pH level by 97%. These bioactivities of MG occurred in a dose‑dependent manner and were significant vs. untreated bacteria. The findings are important for the development of novel pharmaceuticals and formulations of natural products and extracts that possess anti‑biofilm activities with primary applications for oral health, and in a broader context, for the treatment of various bacterial infections.}, } @article {pmid28585390, year = {2017}, author = {Nagar, E and Zilberman, S and Sendersky, E and Simkovsky, R and Shimoni, E and Gershtein, D and Herzberg, M and Golden, SS and Schwarz, R}, title = {Type 4 pili are dispensable for biofilm development in the cyanobacterium Synechococcus elongatus.}, journal = {Environmental microbiology}, volume = {19}, number = {7}, pages = {2862-2872}, doi = {10.1111/1462-2920.13814}, pmid = {28585390}, issn = {1462-2920}, mesh = {Bacterial Adhesion/genetics/physiology ; Biofilms/*growth & development ; Fimbriae, Bacterial/classification/*genetics/metabolism ; Microscopy, Electron ; Synechococcus/*genetics/growth & development ; }, abstract = {The hair-like cell appendages denoted as type IV pili are crucial for biofilm formation in diverse eubacteria. The protein complex responsible for type IV pilus assembly is homologous with the type II protein secretion complex. In the cyanobacterium Synechococcus elongatus PCC 7942, the gene Synpcc7942_2071 encodes an ATPase homologue of type II/type IV systems. Here, we report that inactivation of Synpcc7942_2071 strongly affected the suite of proteins present in the extracellular milieu (exo-proteome) and eliminated pili observable by electron microscopy. These results support a role for this gene product in protein secretion as well as in pili formation. As we previously reported, inactivation of Synpcc7942_2071 enables biofilm formation and suppresses the planktonic growth of S. elongatus. Thus, pili are dispensable for biofilm development in this cyanobacterium, in contrast to their biofilm-promoting function in type IV pili-producing heterotrophic bacteria. Nevertheless, pili removal is not required for biofilm formation as evident by a piliated mutant of S. elongatus that develops biofilms. We show that adhesion and timing of biofilm development differ between the piliated and non-piliated strains. The study demonstrates key differences in the process of biofilm formation between cyanobacteria and well-studied type IV pili-producing heterotrophic bacteria.}, } @article {pmid28583888, year = {2017}, author = {Mahdhi, A and Leban, N and Chakroun, I and Chaouch, MA and Hafsa, J and Fdhila, K and Mahdouani, K and Majdoub, H}, title = {Extracellular polysaccharide derived from potential probiotic strain with antioxidant and antibacterial activities as a prebiotic agent to control pathogenic bacterial biofilm formation.}, journal = {Microbial pathogenesis}, volume = {109}, number = {}, pages = {214-220}, doi = {10.1016/j.micpath.2017.05.046}, pmid = {28583888}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Antioxidants/*pharmacology ; Artemia/drug effects ; Ascorbic Acid/metabolism ; Bacteria/*drug effects ; Biofilms/growth & development ; Cell Line, Tumor ; Cell Survival/drug effects ; Free Radical Scavengers ; Gallic Acid/metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions ; Lactobacillus plantarum/chemistry ; Linoleic Acid/metabolism ; Microbial Sensitivity Tests ; Polysaccharides, Bacterial/chemistry/*pharmacology ; *Prebiotics ; Probiotics/*chemistry ; Toxicity Tests ; }, abstract = {Because of their functional diversity, bioactive compounds are becoming a new biocontrol agent to limit biofilm formation by pathogens. In this study, the physico-chemical characterization of an exopolysaccharide (EPS) isolated from Lactobacillus plantarum (EPLB) was characterized and its in vitro effect on biofilm formation was studied. The EPS had a molecular weight of 36 kDa and polydispersity index estimated to be 1.2. The tested EPLB had an antibacterial activity, with a Minimal Inhibition Concentration (MIC) values ranging between 1 mg/ml and 10 mg/ml, displayed an antibiofilm effect concentration dependent on Gram positive and negative strains. Among the pathogenic strains, 2 out of 4 appeared to be more than 50% inhibited in their biofilm development by the EPS. The antibiofilm activity can be due to the ability of the EPS to influence the function of biological membranes like hydrophobicity that decreased (P < 0.05) when the EPS was used at a concentration of 512 μg/ml. This EPS without cytotoxic effect, showed an antioxidant effect on the quenching of DPPH radicals and the inhibition of lipid peroxidation with a percentage of 64% and 66%, respectively. Taken together these biological properties, EPLB can be considered as a potential prebiotic agent in the design of new therapeutic strategies for bacterial biofilm-associated infections.}, } @article {pmid28582517, year = {2017}, author = {Kim, M and Kim, KS}, title = {Stress-responsively modulated ymdAB-clsC operon plays a role in biofilm formation and apramycin susceptibility in Escherichia coli.}, journal = {FEMS microbiology letters}, volume = {364}, number = {13}, pages = {}, doi = {10.1093/femsle/fnx114}, pmid = {28582517}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Carrier Proteins/genetics/*physiology ; Cold-Shock Response/genetics ; Escherichia coli/*drug effects/genetics/*physiology ; Escherichia coli Proteins/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Microbial Sensitivity Tests ; Nebramycin/*analogs & derivatives/pharmacology ; Operon/genetics/*physiology ; Promoter Regions, Genetic ; Transcription, Genetic ; }, abstract = {The YmdB protein, an inhibitor of biofilm formation and an inducer of apramycin susceptibility in Escherichia coli (E. coli), is part of a putative operon. However, transcription of this operon and its subsequent effects on biological pathways has not been fully studied. Here, we characterized the operon in terms of promoter activity, transcription and function. Promoter activity assays identified two new growth- and cold-shock-responsive upstream (PymdA) and inner (PclsC) promoters, respectively. Moreover, investigation of the operon-derived transcripts identified different polycistronic transcripts harboring multiple heterogeneous 3΄ ends. Overexpression of YmdA or ClsC proteins inhibited biofilm formation and affected apramycin susceptibility, a process dependent on the sucA gene, suggesting that the operon genes or their encoded proteins are functionally linked. Additional investigation of the effects of polycistronic transcripts on the response of E. coli cells to apramycin revealed that transcripts containing ymdA (-213 to +27) are required for apramycin susceptibility. Thus, ymdAB-clsC is a new stress-responsive operon that plays a role in inhibiting undesired biofilm forming and antibiotic-resistant bacterial populations.}, } @article {pmid28581360, year = {2017}, author = {Figueiredo, AMS and Ferreira, FA and Beltrame, CO and Côrtes, MF}, title = {The role of biofilms in persistent infections and factors involved in ica-independent biofilm development and gene regulation in Staphylococcus aureus.}, journal = {Critical reviews in microbiology}, volume = {43}, number = {5}, pages = {602-620}, doi = {10.1080/1040841X.2017.1282941}, pmid = {28581360}, issn = {1549-7828}, mesh = {Bacterial Adhesion/genetics/physiology ; Biofilms/*growth & development ; Communicable Diseases/drug therapy/microbiology/*pathology ; Drug Resistance, Multiple, Bacterial ; Gene Expression Regulation, Bacterial/genetics ; Humans ; Membrane Proteins/genetics/*metabolism ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/drug therapy/microbiology/pathology ; Staphylococcal Infections/drug therapy/microbiology/*pathology ; Staphylococcus aureus/drug effects/*growth & development/*pathogenicity ; }, abstract = {Staphylococcus aureus biofilms represent a unique micro-environment that directly contribute to the bacterial fitness within hospital settings. The accumulation of this structure on implanted medical devices has frequently caused the development of persistent and chronic S. aureus-associated infections, which represent an important social and economic burden worldwide. ica-independent biofilms are composed of an assortment of bacterial products and modulated by a multifaceted and overlapping regulatory network; therefore, biofilm composition can vary among S. aureus strains. In the microniches formed by biofilms-produced by a number of bacterial species and composed by different structural components-drug refractory cell subpopulations with distinct physiological characteristics can emerge and result in therapeutic failures in patients with recalcitrant bacterial infections. In this review, we highlight the importance of biofilms in the development of persistence and chronicity in some S. aureus diseases, the main molecules associated with ica-independent biofilm development and the regulatory mechanisms that modulate ica-independent biofilm production, accumulation, and dispersion.}, } @article {pmid28581211, year = {2017}, author = {Lange, MD and Farmer, BD and Declercq, AM and Peatman, E and Decostere, A and Beck, BH}, title = {Sickeningly Sweet: L-rhamnose stimulates Flavobacterium columnare biofilm formation and virulence.}, journal = {Journal of fish diseases}, volume = {40}, number = {11}, pages = {1613-1624}, doi = {10.1111/jfd.12629}, pmid = {28581211}, issn = {1365-2761}, mesh = {Animals ; Biofilms/*growth & development ; Fish Diseases/*microbiology ; Flavobacteriaceae Infections/microbiology/*veterinary ; Flavobacterium/*drug effects/pathogenicity/physiology ; *Ictaluridae ; Rhamnose/*metabolism ; Virulence ; }, abstract = {Flavobacterium columnare, the causative agent of columnaris disease, causes substantial mortality worldwide in numerous freshwater finfish species. Due to its global significance and impact on the aquaculture industry continual efforts to better understand basic mechanisms that contribute to disease are urgently needed. The current work sought to evaluate the effect of L-rhamnose on the growth characteristics of F. columnare. While we initially did not observe any key changes during the total growth of F. columnare isolates tested when treated with L-rhamnose, it soon became apparent that the difference lies in the ability of this carbohydrate to facilitate the formation of biofilms. The addition of different concentrations of L-rhamnose consistently promoted the development of biofilms among different F. columnare isolates; however, it does not appear to be sufficient as a sole carbon source for biofilm growth. Our data also suggest that iron acquisition machinery is required for biofilm development. Finally, the addition of different concentrations of L-rhamnose to F. columnare prior to a laboratory challenge increased mortality rates in channel catfish (Ictalurus punctatus) as compared to controls. These results provide further evidence that biofilm formation is an integral virulence factor in the initiation of disease in fish.}, } @article {pmid28579399, year = {2017}, author = {Gupta, A and Mishra, S and Singh, S and Mishra, S}, title = {Prevention of IcaA regulated poly N-acetyl glucosamine formation in Staphylococcus aureus biofilm through new-drug like inhibitors: In silico approach and MD simulation study.}, journal = {Microbial pathogenesis}, volume = {110}, number = {}, pages = {659-669}, doi = {10.1016/j.micpath.2017.05.025}, pmid = {28579399}, issn = {1096-1208}, mesh = {Acetylglucosamine/*metabolism ; Adhesins, Bacterial/chemistry/*metabolism ; Anti-Bacterial Agents/chemistry/*metabolism ; Biofilms/*drug effects/*growth & development ; Drug Evaluation, Preclinical ; Molecular Docking Simulation ; Staphylococcus aureus/*drug effects/metabolism/*physiology ; }, abstract = {OBJECTIVES: The effectiveness of various ligands against the protein structure of IcaA of the IcaABCD gene locus of Staphylococcus aureus were examined using the approach of structure based drug designing in reference with the protein's efficiency to form biofilms.

RESULTS: Four compounds CID42738592, CID90468752, CID24277882, and CID6435208 were secluded from a database of 31,242 inhibitory ligands on the justification of the evaluated values falling under the four - tier structure based virtual screening. Under this principle value of least binding energy, human oral absorption and ADME properties were taken into consideration. Using the Glide module of Schrödinger, the above mentioned ligands showed an effective action against the protein IcaA which showed reduced activity as a glucosaminyl transferase. The complex of protein and ligand with best docking score was chosen for simulation studies.

CONCLUSIONS: Structure based drug designing for the protein IcaA has given us potential leads as anti - biofilm agents. These screened out ligands might enable the development of new therapeutic strategies aimed at disrupting Staphylococcus aureus biofilms. The complex was showing stability towards the end of time for which it has been put for simulation. Thus molecule could be considered for making of biofilms.}, } @article {pmid28578279, year = {2017}, author = {Li, X and Lu, Y and Luo, H and Liu, G and Zhang, R}, title = {Microbial stratification structure within cathodic biofilm of the microbial fuel cell using the freezing microtome method.}, journal = {Bioresource technology}, volume = {241}, number = {}, pages = {384-390}, doi = {10.1016/j.biortech.2017.05.137}, pmid = {28578279}, issn = {1873-2976}, mesh = {Bacteria ; *Bioelectric Energy Sources ; *Biofilms ; Electrodes ; Freezing ; }, abstract = {The aim of this study was to investigate the microbial stratification structure within cathodic biofilm of the microbial fuel cell (MFC) using the freezing microtome method. Experiments were conducted in a single-chamber air-cathode MFC with 0.8g/L maltodextrin as substrate for ∼30d operation. The maximum power density was 945±10mW/m[2] in the MFC. Maltodextrin resulted in the relative abundance of Candidatus Saccharibacteria of 37.0% in the anodic biofilm. Different bacterial communities were identified in different layers within the cathodic biofilm. The relative abundance of Enterococcus was 3.7%, 10.5%, and 1.6% in the top (100-150μm), middle (50-100μm), and bottom (0-50μm) layers, respectively. Higher bacterial viability was observed within the top and bottom layers of the cathodic biofilm. Understanding the stratification of bacterial community in cathodic biofilm should be important to control the cathodic biofilm in the MFC.}, } @article {pmid28576759, year = {2017}, author = {Wu, X and Jacobs, NT and Bozio, C and Palm, P and Lattar, SM and Hanke, CR and Watson, DM and Sakai, F and Levin, BR and Klugman, KP and Vidal, JE}, title = {Competitive Dominance within Biofilm Consortia Regulates the Relative Distribution of Pneumococcal Nasopharyngeal Density.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {16}, pages = {}, pmid = {28576759}, issn = {1098-5336}, support = {R21 AI112768/AI/NIAID NIH HHS/United States ; }, mesh = {*Biofilms ; Carrier State/microbiology ; Humans ; Nasopharyngeal Diseases/*microbiology ; Pneumococcal Infections/*microbiology ; Quorum Sensing ; Serogroup ; Streptococcus pneumoniae/genetics/*growth & development/*physiology ; }, abstract = {Streptococcus pneumoniae is a main cause of child mortality worldwide, but strains also asymptomatically colonize the upper airways of most children and form biofilms. Recent studies have demonstrated that ∼50% of colonized children carry at least two different serotypes (i.e., strains) in the nasopharynx; however, studies of how strains coexist are limited. In this work, we investigated the physiological, genetic, and ecological requirements for the relative distribution of densities, and spatial localization, of pneumococcal strains within biofilm consortia. Biofilm consortia were prepared with vaccine type strains (i.e., serotype 6B [S6B], S19F, or S23F) and strain TIGR4 (S4). Experiments first revealed that the relative densities of S6B and S23F were similar in biofilm consortia. The density of S19F strains, however, was reduced to ∼10% in biofilm consortia, including either S6B, S23F, or TIGR4, in comparison to S19F monostrain biofilms. Reduction of S19F density within biofilm consortia was also observed in a simulated nasopharyngeal environment. Reduction of relative density was not related to growth rates, since the Malthusian parameter demonstrated similar rates of change of density for most strains. To investigate whether quorum sensing (QS) regulates relative densities in biofilm consortia, two different mutants were prepared: a TIGR4ΔluxS mutant and a TIGR4ΔcomC mutant. The density of S19F strains, however, was similarly reduced when consortia included TIGR4, TIGR4ΔluxS, or TIGR4ΔcomC Moreover, production of a different competence-stimulating peptide (CSP), CSP1 or CSP2, was not a factor that affected dominance. Finally, a mathematical model, confocal experiments, and experiments using Transwell devices demonstrated physical contact-mediated control of pneumococcal density within biofilm consortia.IMPORTANCEStreptococcus pneumoniae kills nearly half a million children every year, but it also produces nasopharyngeal biofilm consortia in a proportion of asymptomatic children, and these biofilms often contain two strains (i.e., serotypes). In our study, we investigated how strains coexist within pneumococcal consortia produced by vaccine serotypes S4, S6B, S19F, and S23F. Whereas S6B and S23F shared the biofilm consortium, our studies demonstrated reduction of the relative density of S19F strains, to ∼10% of what it would otherwise be if alone, in consortial biofilms formed with S4, S6B, or S23F. This dominance was not related to increased fitness when competing for nutrients, nor was it regulated by quorum-sensing LuxS/AI-2 or Com systems. It was demonstrated, however, to be enhanced by physical contact rather than by a product(s) secreted into the supernatant, as would naturally occur in the semidry nasopharyngeal environment. Competitive interactions within pneumococcal biofilm consortia regulate nasopharyngeal density, a risk factor for pneumococcal disease.}, } @article {pmid28576483, year = {2017}, author = {Wang, J and Liu, W and Liu, T}, title = {Biofilm based attached cultivation technology for microalgal biorefineries-A review.}, journal = {Bioresource technology}, volume = {244}, number = {Pt 2}, pages = {1245-1253}, doi = {10.1016/j.biortech.2017.05.136}, pmid = {28576483}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; *Microalgae ; Technology ; }, abstract = {The attached cultivation for microalga has many superiorities over the conventional aqua-suspend methods, which make it a promising pathway to supply feedstock for microalgae based bio-refinery attempts. In this review, the current reports on bioreactor, application, modeling, substratum material and engineering aspects were summarized and the future research and developments should be focused on the following aspects: 1) Build principles and guidelines for rational structure design by studying the relationship of physiological properties with typical structures and light regimes; 2) Set up theory foundation of substratum material selection by studying the physic-chemical properties of algal cells and substratum materials; 3) Further understanding the mass transfer behaviors of both CO2 and nutrients in biofilm for enhanced growth rate and products accumulation; 4) New equipment and machines for inoculation, harvesting and moisture keeping should be developed and integrated with bioreactor structure.}, } @article {pmid28576044, year = {2017}, author = {Ye, J and Shao, C and Zhang, X and Guo, X and Gao, P and Cen, Y and Ma, S and Liu, Y}, title = {Effects of DNase I coating of titanium on bacteria adhesion and biofilm formation.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {78}, number = {}, pages = {738-747}, doi = {10.1016/j.msec.2017.04.078}, pmid = {28576044}, issn = {1873-0191}, mesh = {Bacterial Adhesion ; *Biofilms ; Deoxyribonuclease I ; Staphylococcus aureus ; Surface Properties ; Titanium ; }, abstract = {The removal of mature biofilm from the surface of implant has been a formidable challenge in treating implant-associated infection. Prevention of biofilm formation rather than removal of existing biofilm is a more effective approach. Immobilization of biofilm-dispersing enzymes on material surfaces is regarded as one of the most promising strategies. Deoxyribonuclease I (DNase I) can degrade extracellular DNA (eDNA) and then destabilize biofilm. In this study, DNase I was immobilized on a titanium (Ti) surface by using dopamine as an intermediate. The water contact angle, SEM, EDS and XPS confirmed that DNase I was successfully coated to the bare Ti and the final coating was highly hydrophilic. The DNase I coating showed significant effects in preventing Streptococcus mutans (S. mutans) and Staphylococcus aureus (S. aureus) adhesion and biofilm formation over a time span of 24h. The favorable biocompatibility was demonstrated by cell study in vitro. In addition, cell adhesion results suggested that DNase I coating had the potential to facilitate MC3T3-E1 cell attachment. DNase I coating with anti-infection ability and biocompatibility has great potential for increasing success rates of implant applications.}, } @article {pmid28576036, year = {2017}, author = {Del Campo, R and Savoini, B and Jordao, L and Muñoz, A and Monge, MA}, title = {Cytocompatibility, biofilm assembly and corrosion behavior of Mg-HAP composites processed by extrusion.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {78}, number = {}, pages = {667-673}, doi = {10.1016/j.msec.2017.04.143}, pmid = {28576036}, issn = {1873-0191}, mesh = {*Biofilms ; Corrosion ; Magnesium ; Materials Testing ; Staphylococcus aureus ; }, abstract = {In this work the cytocompatibility of pure magnesium and Mg-xHAP composites (x=5, 10 and 15wt%) fabricated by powder metallurgy routes has been investigated. The materials were produced from raw HAP powders with particle mean sizes of 6μm (S-xHAP) or 25μm (L-xHAP). The biocompatibility study has been performed for MC3T3 cells (osteoblasts/osteoclasts) and L929 fibroblasts. The results indicate that S-Mg (pure magnesium), S-10HAP and L-10HAP composites are the materials with the best biocompatibility. The ability of S. aureus bacteria to assemble biofilms was also evaluated. Biofilm formation assays showed that these materials are not particular prone to colonization and biofilm assembly is strain dependent. The corrosion resistance of S-Mg, S-10HAP and L-10HAP materials immersed in the media used for the cells culture has also been analyzed. Different trends in the corrosion resistance have been found: S-Mg and S-10HAP show a very high resistance to corrosion whereas the corrosion of L-10HAP steadily increases with time.}, } @article {pmid28575838, year = {2017}, author = {Qiao, YJ and Qiao, Y and Zou, L and Wu, XS and Liu, JH}, title = {Biofilm promoted current generation of Pseudomonas aeruginosa microbial fuel cell via improving the interfacial redox reaction of phenazines.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {117}, number = {}, pages = {34-39}, doi = {10.1016/j.bioelechem.2017.04.003}, pmid = {28575838}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/*microbiology ; *Biofilms ; *Electric Conductivity ; Electrochemistry ; Electrodes ; Electron Transport ; Phenazines/*metabolism ; Pseudomonas aeruginosa/metabolism/*physiology ; }, abstract = {Bacteria biofilm plays a key role in current generation of microbial fuel cells (MFCs), especially for the start-up stage. However, the detailed mechanism of the biofilm promoting the power generation is not very clear so far, especially for those exoelectrogens who rely on the self-excreted electron mediators for extracellular electron transfer. In this work, a biofilm formation inhibitor-sodium houttuyfonate (SH) is used to build a "non-biofilm" anode of Pseudomonas aeruginosa (P. aeruginosa) without affecting the bacteria growth during the MFC operation. According to the comparison results of the "non-biofilm" anode and biofilm-covered anode on current generation, phenazines concentration variation and anodic electrocatalysis, the biofilm on the anode not only provides plenty of bacterial cells for catalysis but also promotes the interfacial phenazine redox reaction through accumulating the self-generated mediators on anode for fast interfacial electron transfer. This work proves that the biofilm assisted electron mediator accumulation will benefit such kind of exoelectrogens to sustain sufficient electron mediators for extracellular electron transfer.}, } @article {pmid28575837, year = {2017}, author = {Mei, X and Xing, D and Yang, Y and Liu, Q and Zhou, H and Guo, C and Ren, N}, title = {Adaptation of microbial community of the anode biofilm in microbial fuel cells to temperature.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {117}, number = {}, pages = {29-33}, doi = {10.1016/j.bioelechem.2017.04.005}, pmid = {28575837}, issn = {1878-562X}, mesh = {*Adaptation, Physiological ; *Bacterial Physiological Phenomena ; Bioelectric Energy Sources/*microbiology ; *Biofilms ; RNA, Ribosomal, 16S/genetics ; Temperature ; }, abstract = {Temperature as an important ecological factor affects biofilm development and microbial metabolic activity. Here, the performances and microbial communities of microbial fuel cells (MFCs) at different temperature were analyzed. As the temperature decreased, the power output of MFCs declined. A maximum power density of 894.3±48.6mW/m[2] was obtained in MFCs operating at 30°C, which was 18.5% and 64.5% higher than that in MFCs at 20°C and 10°C, respectively. Illumina sequencing of 16S rRNA gene amplicons showed that a distinct difference in microbial community structure of the anode biofilms occurred. This resulted in different power outputs of MFCs. Species diversity analyses indicated that species evenness of the anode biofilms shifted beyond species richness at different temperatures. The predominant populations of the anode biofilm shifted from Geobacter and Azonexus (30°C) to Pelobacter (20°C) or Acidovorax, Zoogloea and Simplicispira, (10°C). These results indicate that temperature plays an important role in shaping microbial communities of the anode biofilms in MFCs through changes in species evenness.}, } @article {pmid28575223, year = {2017}, author = {Yssel, AEJ and Vanderleyden, J and Steenackers, HP}, title = {Repurposing of nucleoside- and nucleobase-derivative drugs as antibiotics and biofilm inhibitors.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {8}, pages = {2156-2170}, doi = {10.1093/jac/dkx151}, pmid = {28575223}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; *Drug Repositioning ; Humans ; Nucleosides/*pharmacology ; }, abstract = {There is an urgent need for new antibacterial drugs that are robust against the development of resistance. Drug repurposing is a cost-effective strategy to fast-track the drug development process. Here we examine why the nucleoside and nucleobase analogue drugs in particular present an attractive class for repurposing. Some of these drugs have already been evaluated for their potential as antibacterial agents. In addition to inhibiting bacterial growth and survival, some also act synergistically with antibiotics, and as such can enhance the therapeutic spectrum of currently available antibiotics. Furthermore, nucleoside and nucleobase analogue drugs can inhibit bacterial virulence and biofilm formation. Biofilms are known to impart antibiotic tolerance and are associated with chronic infections. Targeting biofilm formation thus renders pathogens more susceptible to antibiotic treatment and host immune defences. Moreover, specific analogues have properties that make them less susceptible to the development of resistance. Thus, nucleoside and nucleobase analogue drugs ought to be considered as new weapons in our fight against pathogenic bacteria.}, } @article {pmid28573605, year = {2017}, author = {Shafreen, RB and Seema, S and Ahamed, AP and Thajuddin, N and Ali Alharbi, S}, title = {Inhibitory Effect of Biosynthesized Silver Nanoparticles from Extract of Nitzschia palea Against Curli-Mediated Biofilm of Escherichia coli.}, journal = {Applied biochemistry and biotechnology}, volume = {183}, number = {4}, pages = {1351-1361}, doi = {10.1007/s12010-017-2503-7}, pmid = {28573605}, issn = {1559-0291}, support = {F.4-2/2006 (BSR)/BL/13-14/0151//University Grants Committee/ ; YSS/20l4/000127//Science and Engineering Research Board/ ; SR/FT/LS-113/2009//DST PURSE/ ; }, mesh = {Biofilms/*growth & development ; Diatoms/*chemistry ; Escherichia coli/*physiology ; Metal Nanoparticles/*chemistry ; Plant Extracts/*chemistry ; Silver/*chemistry ; }, abstract = {Extended spectrum beta lactamase (ESBL) are emerging beta-lactamases in Gram-negative pathogens, causing serious problems in hospitalized patients worldwide. Biofilm mode of virulence has decreased the efficiency of antibiotics used for treatment against ESBL pathogens. Therefore, there is an urgent need for alternative agents such as nanoparticles that can prevent and inhibit the biofilm formation. The aim of the present study was to inhibit the biofilm formed by ESBL-producing Escherichia coli using silver nanoparticles (AgNPs) synthesized with fresh water diatom (Nitzschia palea). AgNPs were characterized using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and XRD. AgNPs at their biofilm inhibitory concentration (BIC) of 300 ng ml[-1] significantly reduced the biofilm formed by E. coli. Interestingly, Congo red assay revealed the reduction of curli, essential for biofilm formation in the presence of AgNPs. Light and CLSM examination of the biofilm images also validated that in the presence of AgNPs, the biofilm architecture was disintegrated and the thickness was significantly reduced. Overall, the present study exemplifies the use of AgNPs as a plausible alternative for conventional coating agents on implant devices to prevent and control biofilm-associated urinary tract infections.}, } @article {pmid28570133, year = {2017}, author = {Malone, M and Swanson, T}, title = {Biofilm-based wound care: the importance of debridement in biofilm treatment strategies.}, journal = {British journal of community nursing}, volume = {22}, number = {Sup6}, pages = {S20-S25}, doi = {10.12968/bjcn.2017.22.Sup6.S20}, pmid = {28570133}, issn = {1462-4753}, mesh = {Anti-Bacterial Agents/*therapeutic use ; *Biofilms ; *Debridement ; Humans ; Wound Infection/microbiology/*therapy ; Wounds and Injuries/microbiology/*therapy ; }, } @article {pmid28569892, year = {2017}, author = {Ho, KKK and Ozcelik, B and Willcox, MDP and Thissen, H and Kumar, N}, title = {Facile solvent-free fabrication of nitric oxide (NO)-releasing coatings for prevention of biofilm formation.}, journal = {Chemical communications (Cambridge, England)}, volume = {53}, number = {48}, pages = {6488-6491}, doi = {10.1039/c7cc02772a}, pmid = {28569892}, issn = {1364-548X}, mesh = {Amines/*chemistry ; Azo Compounds/*chemistry ; Bacterial Adhesion ; *Biofilms ; Gram-Negative Bacteria/metabolism ; Gram-Positive Bacteria/metabolism ; Nitric Oxide/*chemistry ; Polymers/*chemistry ; }, abstract = {We describe a simple and solvent-free method to generate nitric oxide (NO)-releasing coatings by incorporating diazeniumdiolate (NONOate) into allylamine or diallylamine plasma polymer coatings. The resulting coatings demonstrate continuous release of NO for over 48 hours and are effective at reducing the adhesion and biofilm formation of medically-relevant Gram-negative and Gram-positive opportunistic pathogens.}, } @article {pmid28567419, year = {2017}, author = {Minami, M and Konishi, T and Takase, H and Makino, T}, title = {Shin'iseihaito (Xinyiqingfeitang) Suppresses the Biofilm Formation of Streptococcus pneumoniae In Vitro.}, journal = {BioMed research international}, volume = {2017}, number = {}, pages = {4575709}, pmid = {28567419}, issn = {2314-6141}, mesh = {Biofilms/*drug effects ; Drugs, Chinese Herbal/*pharmacology ; Humans ; Medicine, Kampo/*methods ; Streptococcus pneumoniae/*physiology ; }, abstract = {Streptococcus pneumoniae (S. pneumoniae) is the important pathogen that causes otolaryngeal diseases such as sinusitis. S. pneumoniae frequently forms the biofilm to prevent severe circumstances such as antimicrobial agents. Shin'iseihaito (xinyiqingfeitang) is a formula of Japanese traditional Kampo medicine that has 9 crude drugs and provides the medicinal usage for sinusitis. The objective of the present study is to reveal the mechanism of antibiofilm activity by Shin'iseihaito extract (SSHT). SSHT significantly inhibited the formation of biofilm from S. pneumoniae ATCC 49619 in dose- and time-dependent manners. SSHT also significantly suppressed the biofilm formation by other five different cps types of S. pneumoniae clinical isolates. We found that the extracts of 8 out of 9 components in Shin'iseihaito had the inhibitory effects of biofilm formation, and the extract of the root of Scutellaria baicalensis had the strongest effect among the ingredients of Shin'iseihaito. We found that the capsule of SSHT-treated S. pneumoniae was significantly thinner than that of the untreated group and that SSHT reduced the hydrophobicity of bacterial cell surface. Our results suggest that Shin'iseihaito may be a useful agent for the treatment of S. pneumoniae-induced sinusitis because of the inhibition of biofilm formation of S. pneumoniae.}, } @article {pmid28567253, year = {2016}, author = {Hu, Y and Zou, W and Julita, V and Ramanathan, R and Tabor, RF and Nixon-Luke, R and Bryant, G and Bansal, V and Wilkinson, BL}, title = {Photomodulation of bacterial growth and biofilm formation using carbohydrate-based surfactants.}, journal = {Chemical science}, volume = {7}, number = {11}, pages = {6628-6634}, pmid = {28567253}, issn = {2041-6520}, abstract = {Naturally occurring and synthetic carbohydrate amphiphiles have emerged as a promising class of antimicrobial and antiadhesive agents that act through a number of dynamic and often poorly understood mechanisms. In this paper, we provide the first report on the application of azobenzene trans-cis photoisomerization for effecting spatial and temporal control over bacterial growth and biofilm formation using carbohydrate-based surfactants. Photocontrollable surface tension studies and small angle neutron scattering (SANS) revealed the diverse geometries and dimensions of self-assemblies (micelles) made possible through variation of the head group and UV-visible light irradiation. Using these light-addressable amphiphiles, we demonstrate optical control over the antibacterial activity and formation of biofilms against multi-drug resistant (MDR) Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli. To probe the mechanism of bioactivity further, we evaluated the impact of trans-cis photoisomerization in these surfactants on bacterial motility and revealed photomodulated enhancement in swarming motility in P. aeruginosa. These light-responsive amphiphiles should attract significant interest as a new class of antibacterial agents and as investigational tools for probing the complex mechanisms underpinning bacterial adhesion and biofilm formation.}, } @article {pmid28567055, year = {2017}, author = {Kim, KH and Loch, C and Waddell, JN and Tompkins, G and Schwass, D}, title = {Surface Characteristics and Biofilm Development on Selected Dental Ceramic Materials.}, journal = {International journal of dentistry}, volume = {2017}, number = {}, pages = {7627945}, pmid = {28567055}, issn = {1687-8728}, abstract = {BACKGROUND: Intraoral adjustment and polishing of dental ceramics often affect their surface characteristics, promoting increased roughness and consequent biofilm growth. This study correlated surface roughness to biofilm development with four commercially available ceramic materials.

METHODS: Four ceramic materials (Vita Enamic®, Lava™ Ultimate, Vitablocs Mark II, and Wieland Reflex®) were prepared as per manufacturer instructions. Seventeen specimens of each material were adjusted and polished to simulate clinical intraoral procedures and another seventeen remained unaltered. Specimens were analysed by SEM imaging, confocal microscopy, and crystal violet assay.

RESULTS: SEM images showed more irregular surface topography in adjusted specimens than their respective controls. Surface roughness (Ra) values were greater in all materials following adjustments. All adjusted materials with the exception of Vitablocs Mark II promoted significantly greater biofilm growth relative to controls.

CONCLUSION: Simulated intraoral polishing methods resulted in greater surface roughness and increased biofilm accumulation.}, } @article {pmid28567031, year = {2017}, author = {Cherifi, T and Jacques, M and Quessy, S and Fravalo, P}, title = {Impact of Nutrient Restriction on the Structure of Listeria monocytogenes Biofilm Grown in a Microfluidic System.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {864}, pmid = {28567031}, issn = {1664-302X}, abstract = {Biofilm formation by the pathogen Listeria monocytogenes is a major concern in food industries. The aim of this work was to elucidate the effect of nutrient limitation on both biofilm architecture and on the viability of the bacteria in microfluidic growth conditions. Biofilm formation by two L. monocytogenes strains was performed in a rich medium (BHI) and in a 10-fold diluted BHI (BHI/10) at 30°C for 24 h by using both static conditions and the microfluidic system Bioflux. In dynamic conditions, biofilms grown in rich and poor medium showed significant differences as well in structure and in the resulting biovolume. In BHI/10, biofilm was organized in a knitted network where cells formed long chains, whereas in the rich medium, the observed structure was homogeneous cellular multilayers. Biofilm biovolume production in BHI/10 was significantly higher than in BHI in these dynamic conditions. Interestingly, biovolume of dead cells in biofilms formed under limited nutrient conditions (BHI/10) was significantly higher than in biofilms formed in the BHI medium. In the other hand, in static conditions, biofilm is organized in a multilayer cells and dispersed cells in a rich medium BHI and poor medium BHI/10 respectively. There was significantly more biomass in the rich medium compared to BHI/10 but no difference was noted in the dead/damaged subpopulation showing how L. monocytogenes biofilm could be affected by the growth conditions. This work demonstrated that nutrient concentration affects biofilm structure and the proportion of dead cells in biofilms under microfluidic condition. Our study also showed that limited nutrients play an important role in the structural stability of L. monocytogenes biofilm by enhancing cell death and liberating extracellular DNA.}, } @article {pmid28561911, year = {2017}, author = {Azara, E and Longheu, C and Sanna, G and Tola, S}, title = {Biofilm formation and virulence factor analysis of Staphylococcus aureus isolates collected from ovine mastitis.}, journal = {Journal of applied microbiology}, volume = {123}, number = {2}, pages = {372-379}, doi = {10.1111/jam.13502}, pmid = {28561911}, issn = {1365-2672}, mesh = {Adhesins, Bacterial/genetics ; Animals ; Bacterial Proteins/genetics/*metabolism ; Bacterial Toxins/metabolism ; *Biofilms ; Enterotoxins/metabolism ; Female ; Genotype ; Italy ; Mastitis/microbiology/*veterinary ; Polymerase Chain Reaction ; Sheep ; Sheep Diseases/*microbiology ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/genetics/isolation & purification/*physiology ; Superantigens/metabolism ; Virulence Factors/genetics/*metabolism ; }, abstract = {AIMS: To perform a phenotypic and genotypic characterization of 258 Staphylococcus aureus isolates from clinical ovine mastitis and used for the preparation of inactivated autogenous vaccines.

METHODS AND RESULTS: The potential for biofilm production was determined by phenotypic test of Congo Red Agar (CRA) and by PCR for the detection of icaA/D genes. Isolates were also screened by PCR for the presence of enterotoxins (sea, seb, sec, sed and see), toxic shock syndrome toxin (tsst), leukotoxins (lukD-E, lukM and lukPV83), haemolysins (hly-β and hly-γ), autolysin (atlA) genes and encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs: clfA, clfB, fnbA, fnbB, bbp, cna, eno, fib, epbs, sdrC, sdrD and SdrE). None of the 258 isolates showed biofilm-forming ability on CRA and harboured icaA/D genes. The most frequent pyrogenic toxin superantigen genes amplified were sec plus tsst-1, which were found strictly in combination with 71·3% of the Staph. aureus isolates tested. None of the isolates harboured the genes encoding sea and see. Of the 258 isolates tested, 159 (61·6%) possessed all lukD-E/lukM/lukPV83 genes, 123 (47·7%) harboured both hly-β/hly-γ genes, whereas almost all (97·3%) were PCR positive for atlA gene. With respect to adhesion determinants, 179 (69·4%) isolates presented simultaneously four genes (fnbA, fib, clfA and clfB) for fibronectin- and fibrinogen-binding proteins.

CONCLUSIONS: In this search, several putative virulence determinants have been identified in ovine Staph. aureus isolates collected in Sardinia.

Some of the putative virulence determinants could be considered as components of a vaccine because of their role in ovine mastitis pathogenesis.}, } @article {pmid28561639, year = {2017}, author = {Chylkova, T and Cadena, M and Ferreiro, A and Pitesky, M}, title = {Susceptibility of Salmonella Biofilm and Planktonic Bacteria to Common Disinfectant Agents Used in Poultry Processing.}, journal = {Journal of food protection}, volume = {80}, number = {7}, pages = {1072-1079}, doi = {10.4315/0362-028X.JFP-16-393}, pmid = {28561639}, issn = {1944-9097}, mesh = {Animals ; Biofilms ; Disinfectants/*pharmacology ; Food Handling/*methods ; Plankton/*drug effects ; Poultry/*microbiology ; Salmonella/*drug effects ; }, abstract = {Poultry contaminated with Salmonella enterica subsp. enterica are a major cause of zoonotic foodborne gastroenteritis. Salmonella Heidelberg is a common serotype of Salmonella that has been implicated as a foodborne pathogen associated with the consumption of improperly prepared chicken. To better understand the effectiveness of common antimicrobial disinfectants (i.e., peroxyacetic acid [PAA], acidified hypochlorite [aCH], and cetylpyridinium chloride [CPC]), environmental isolates of nontyphoidal Salmonella were exposed to these agents under temperature, concentration, and contact time conditions consistent with poultry processing. Under simulated processing conditions (i.e., chiller tank and dipping stations), the bacteriostatic and bactericidal effects of each disinfectant were assessed against biofilm and planktonic cultures of each organism in a disinfectant challenge. Log reductions, planktonic MICs, and mean biofilm eradication concentrations were computed. The biofilms of each Salmonella isolate were more resistant to the disinfectants than were their planktonic counterparts. Although PAA was bacteriostatic and bactericidal against the biofilm and planktonic Salmonella isolates tested at concentrations up to 64 times the concentrations commonly used in a chiller tank during poultry processing, aCH was ineffective against the same isolates under identical conditions. At the simulated 8-s dipping station, CPC was bacteriostatic against all seven and bactericidal against six of the seven Salmonella isolates in their biofilm forms at concentrations within the regulatory range. These results indicate that at the current contact times and concentrations, aCH and PAA are not effective against these Salmonella isolates in their biofilm state. The use of CPC should be considered as a tool for controlling Salmonella biofilms in poultry processing environments.}, } @article {pmid28561567, year = {2017}, author = {Yavvari, PS and Gupta, S and Arora, D and Nandicoori, VK and Srivastava, A and Bajaj, A}, title = {Clathrin-Independent Killing of Intracellular Mycobacteria and Biofilm Disruptions Using Synthetic Antimicrobial Polymers.}, journal = {Biomacromolecules}, volume = {18}, number = {7}, pages = {2024-2033}, doi = {10.1021/acs.biomac.7b00106}, pmid = {28561567}, issn = {1526-4602}, mesh = {*Anti-Bacterial Agents/chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Clathrin ; Humans ; Mycobacterium bovis/*physiology ; Mycobacterium smegmatis/*physiology ; *Nylons/chemical synthesis/chemistry/pharmacology ; THP-1 Cells ; }, abstract = {Current membrane targeting antimicrobials fail to target mycobacteria due to their hydrophobic membrane structure, ability to form drug-resistant biofilms, and their natural intracellular habitat within the confines of macrophages. In this work, we describe engineering of synthetic antimicrobial polymers (SAMPs) derived from biocompatible polyamides that can target drug-sensitive and drug-resistant mycobacteria with high selectivity. Structure-activity relationship studies revealed that reduced hydrophobicity of cationic pendants induces enhanced and selective permeabilization of mycobacterial membranes. The least hydrophobic SAMP (TAC1) was found to be the most active with maximum specificity toward mycobacteria over E. coli, S. aureus, and mammalian cells. Membrane perturbation studies, scanning electron microscopy, and colony PCR confirmed the ability of TAC1 to induce membrane lysis and to bind to the genomic material of mycobacteria, thereby inducing mycobacterial cell death. TAC1 was most effective in perfusing and disrupting the mycobacterial biofilms and was also able to kill the intracellular mycobacteria effectively without inducing any toxicity to mammalian cells. Cellular uptake studies revealed clathrin independent uptake of TAC1, thereby allowing it to escape hydrolytic lysosomal degradation and effectively kill the intracellular bacteria. Therefore, this manuscript presents the design and selective antimycobacterial nature of polyamide polymers with charged hydrophobic pendants that have ability to disrupt the biofilms and kill intracellular mycobacteria.}, } @article {pmid28560581, year = {2017}, author = {Cazalini, EM and Miyakawa, W and Teodoro, GR and Sobrinho, ASS and Matieli, JE and Massi, M and Koga-Ito, CY}, title = {Antimicrobial and anti-biofilm properties of polypropylene meshes coated with metal-containing DLC thin films.}, journal = {Journal of materials science. Materials in medicine}, volume = {28}, number = {6}, pages = {97}, pmid = {28560581}, issn = {1573-4838}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*chemistry ; Bacterial Adhesion ; *Biofilms ; Candida albicans ; Carbon/*chemistry ; Chromium/chemistry ; Coated Materials, Biocompatible/chemistry ; Cobalt/chemistry ; Diamond/*chemistry ; Enterococcus faecalis ; Escherichia coli ; Humans ; Metals/*chemistry ; Microbial Sensitivity Tests ; Polypropylenes/*chemistry ; Pseudomonas aeruginosa ; Silver/chemistry ; Staphylococcus aureus ; Surface Properties ; Tantalum/chemistry ; Titanium/chemistry ; }, abstract = {A promising strategy to reduce nosocomial infections related to prosthetic meshes is the prevention of microbial colonization. To this aim, prosthetic meshes coated with antimicrobial thin films are proposed. Commercial polypropylene meshes were coated with metal-containing diamond-like carbon (Me-DLC) thin films by the magnetron sputtering technique. Several dissimilar metals (silver, cobalt, indium, tungsten, tin, aluminum, chromium, zinc, manganese, tantalum, and titanium) were tested and compositional analyses of each Me-DLC were performed by Rutherford backscattering spectrometry. Antimicrobial activities of the films against five microbial species (Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis) were also investigated by a modified Kirby-Bauer test. Results showed that films containing silver and cobalt have inhibited the growth of all microbial species. Tungsten-DLC, tin-DLC, aluminum-DLC, zinc-DLC, manganese-DLC, and tantalum-DLC inhibited the growth of some strains, while chromium- and titanium-DLC weakly inhibited the growth of only one tested strain. In-DLC film showed no antimicrobial activity. The effects of tungsten-DLC and cobalt-DLC on Pseudomonas aeruginosa biofilm formation were also assessed. Tungsten-DLC was able to significantly reduce biofilm formation. Overall, the experimental results in the present study have shown new approaches to coating polymeric biomaterials aiming antimicrobial effect.}, } @article {pmid28559883, year = {2017}, author = {Krzyściak, W and Papież, M and Jurczak, A and Kościelniak, D and Vyhouskaya, P and Zagórska-Świeży, K and Skalniak, A}, title = {Relationship between Pyruvate Kinase Activity and Cariogenic Biofilm Formation in Streptococcus mutans Biotypes in Caries Patients.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {856}, pmid = {28559883}, issn = {1664-302X}, abstract = {Streptococcus mutans (MS) and its biotype I are the strains most frequently found in dental plaque of young children. Our results indicate that in children pyruvate kinase (PK) activity increases significantly in dental plaque, and this corresponds with caries progression. The MS strains isolated in this study or their main glycolytic metabolism connected with PK enzymes might be useful risk factors for studying the pathogenesis and target points of novel therapies for dental caries. The relationship between PK activity, cariogenic biofilm formation and selected biotypes occurrence was studied. S. mutans dental plaque samples were collected from supragingival plaque of individual deciduous molars in 143 subjects. PK activity was measured at different time points during biofilm formation. Patients were divided into two groups: initial stage decay, and extensive decay. Non-parametric analysis of variance and analysis of covariance were used to determine the connections between S. mutans levels, PK activity and dental caries biotypes. A total of 143 strains were derived from subjects with caries. Biotyping data showed that 62, 23, 50, and 8 strains were classified as biotypes I, II, III, IV, respectively. PK activity in biotypes I, II, and IV was significantly higher in comparison to that in biotype III. The correlation between the level of S. mutans in dental plaque and PK activity was both statistically significant (p < 0.05) and positive. The greater the level of S. mutans in the biofilm (colony count and total biomass), the higher the PK activity; similarly, a low bacterial count correlated with low PK activity.}, } @article {pmid28559403, year = {2017}, author = {Nicholson, TL and Brockmeier, SL and Sukumar, N and Paharik, AE and Lister, JL and Horswill, AR and Kehrli, ME and Loving, CL and Shore, SM and Deora, R}, title = {The Bordetella Bps Polysaccharide Is Required for Biofilm Formation and Enhances Survival in the Lower Respiratory Tract of Swine.}, journal = {Infection and immunity}, volume = {85}, number = {8}, pages = {}, pmid = {28559403}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; HHSN272201200005C/AI/NIAID NIH HHS/United States ; R01 AI125560/AI/NIAID NIH HHS/United States ; R21 AI123805/AI/NIAID NIH HHS/United States ; I01 BX002711/BX/BLRD VA/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Bordetella Infections/immunology/*microbiology ; Bordetella bronchiseptica/chemistry/genetics/immunology/*pathogenicity ; Bronchi/microbiology ; Gene Expression Regulation, Bacterial ; Mutation ; Nose/microbiology ; Polysaccharides, Bacterial/*metabolism ; Swine ; Trachea/*microbiology ; }, abstract = {Bordetella bronchiseptica is pervasive in swine populations and plays multiple roles in respiratory disease. Additionally, B. bronchiseptica is capable of establishing long-term or chronic infections in swine. Bacterial biofilms are increasingly recognized as important contributors to chronic bacterial infections. Recently the polysaccharide locus bpsABCD has been demonstrated to serve a critical role in the development of mature biofilms formed by the sequenced laboratory strain of B. bronchiseptica We hypothesized that swine isolates would also have the ability to form mature biofilms and the bpsABCD locus would serve a key role in this process. A mutant containing an in-frame deletion of the bpsABCD structural genes was constructed in a wild-type swine isolate and found to be negative for poly-N-acetylglucosamine (PNAG)-like material by immunoblot assay. Further, the bpsABCD locus was found to be required for the development and maintenance of the three-dimensional structures under continuous-flow conditions. To investigate the contribution of the bpsABCD locus to the pathogenesis of B. bronchiseptica in swine, the KM22Δbps mutant was compared to the wild-type swine isolate for the ability to colonize and cause disease in pigs. The bpsABCD locus was found to not be required for persistence in the upper respiratory tract of swine. Additionally, the bpsABCD locus did not affect the development of anti-Bordetella humoral immunity, did not contribute to disease severity, and did not mediate protection from complement-mediated killing. However, the bpsABCD locus was found to enhance survival in the lower respiratory tract of swine.}, } @article {pmid28559263, year = {2017}, author = {Poonacha, N and Nair, S and Desai, S and Tuppad, D and Hiremath, D and Mohan, T and Vipra, A and Sharma, U}, title = {Efficient Killing of Planktonic and Biofilm-Embedded Coagulase-Negative Staphylococci by Bactericidal Protein P128.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {8}, pages = {}, pmid = {28559263}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/drug therapy/microbiology ; Coagulase/metabolism ; Daptomycin/pharmacology ; Drug Synergism ; Drug Therapy, Combination ; Foreign-Body Reaction/drug therapy/microbiology ; Humans ; Microbial Sensitivity Tests ; Recombinant Fusion Proteins/*pharmacology ; Staphylococcal Infections/*drug therapy ; Staphylococcus epidermidis/*drug effects/enzymology ; Staphylococcus haemolyticus/*drug effects/enzymology ; Staphylococcus lugdunensis/*drug effects/enzymology ; Vancomycin/pharmacology ; }, abstract = {Coagulase-negative staphylococci (CoNS) are the major causative agents of foreign-body-related infections, including catheter-related bloodstream infections. Because of the involvement of biofilms, foreign-body-related infections are difficult to treat. P128, a chimeric recombinant phage-derived ectolysin, has been shown to possess bactericidal activity on strains of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). We tested the killing potential of P128 on three clinically significant species of CoNS, S. epidermidis, S. haemolyticus, and S. lugdunensis, under a variety of physiological conditions representing growing and nongrowing states. The MIC90 and minimum bactericidal concentration at which 90% of strains tested are killed (MBC90) of P128 on 62 clinical strains of CoNS were found to be 16 and 32 μg/ml (0.58 and 1.16 μM), respectively, demonstrating the bactericidal nature of P128 on CoNS strains. Serum showed a potentiating effect on P128 inhibition, as indicated by 4- to 32-fold lower MIC values observed in serum. P128 caused a rapid loss of viability in all CoNS strains tested. Persisters of CoNS that were enriched in the presence of vancomycin or daptomycin were killed by P128 at 1× the MIC in a rapid manner. Low concentrations of P128 caused a 2- to 5-log reduction in CFU in stationary-phase or poorly metabolizing CoNS cultures. P128 at low concentrations eliminated CoNS biofilms in microtiter plates and on the surface of catheters. Combinations of P128 and standard-of-care (SoC) antibiotics were highly synergistic in inhibiting growth in preformed biofilms. Potent activity on planktonic cells, persisters, and biofilms of CoNS suggests that P128 is a promising candidate for the clinical development of treatments for foreign-body-related and other CoNS infections.}, } @article {pmid28558916, year = {2018}, author = {Macià, MD and Del Pozo, JL and Díez-Aguilar, M and Guinea, J}, title = {Microbiological diagnosis of biofilm-related infections.}, journal = {Enfermedades infecciosas y microbiologia clinica (English ed.)}, volume = {36}, number = {6}, pages = {375-381}, doi = {10.1016/j.eimc.2017.04.006}, pmid = {28558916}, issn = {2529-993X}, mesh = {Bacterial Infections/*diagnosis/etiology/microbiology ; *Biofilms ; Biopsy ; Catheter-Related Infections/diagnosis/etiology/microbiology ; Disease Susceptibility ; Drug Resistance, Microbial ; Foreign Bodies ; Humans ; Pneumonia, Ventilator-Associated/diagnosis/etiology/microbiology ; Prostheses and Implants/adverse effects ; Prosthesis-Related Infections/diagnosis/etiology/microbiology ; Specimen Handling ; Surgical Wound Infection/diagnosis/etiology/microbiology ; }, abstract = {Biofilm-related infections represent a serious health problem, accounting for 65- 80% of all infections. The infections are generally chronic and characterized by the persistence of the microorganism, due to the increased resistance of biofilms to both the immune system and antimicrobials. Biofilms can be located to almost every human body tissue and on exogenous devices such as catheters, pacemakers, prosthetic material, implants, urinary catheters, etc. Traditional antimicrobial susceptibility studies in clinical microbiology laboratories have lied on the study of planktonic form of microorganisms. However, this approach might lead to miss the biofilm characteristics and to a treatment failure. Microbiological diagnosis and antimicrobial susceptibility studies of biofilm-related infections are complex and, nowadays, represent a challenge that clinicians and microbiologists have to address as a team in the absence of consensus or standardized protocols.}, } @article {pmid28558683, year = {2017}, author = {Bhunu, B and Mautsa, R and Mukanganyama, S}, title = {Inhibition of biofilm formation in Mycobacterium smegmatis by Parinari curatellifolia leaf extracts.}, journal = {BMC complementary and alternative medicine}, volume = {17}, number = {1}, pages = {285}, pmid = {28558683}, issn = {1472-6882}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests ; Mycobacterium smegmatis/drug effects/physiology ; Mycobacterium tuberculosis/*drug effects/physiology ; Plant Extracts/isolation & purification/*pharmacology ; Plant Leaves/chemistry ; }, abstract = {BACKGROUND: Tuberculosis (TB) is a serious public health problem worldwide. Mycobacterium tuberculosis (M. tuberculosis) grows as drug tolerant pellicles. Agents that inhibit biofilm formation in M. tuberculosis have the potential to reduce the disease treatment period and improve the quality of tuberculosis chemotherapy. Parinari curatellifolia (P. curatellifolia) leaf extracts are claimed to treat symptoms similar to tuberculosis in ethnomedicinal practices. Mycobacterium smegmatis (M. smegmatis) is a surrogate organism used in antimycobacterial drug discovery assays. In this study, the effect of the leaf extracts of P. curatellifolia on M. smegmatis growth and biofilm formation was investigated in order to determine the basis of its use in traditional medicinal use.

METHODS: Phytochemicals from P. curatellifolia leaves were prepared using a mixture of 50% dichloromethane (DCM): 50% methanol and by serial exhaustive extraction using different solvents of decreasing polarity. The solvents were used in the following order, hexane > dichloromethane > ethyl acetate > acetone >ethanol > methanol > water. The micro-broth dilution method was used as an antimycobacterial susceptibility test to screen for the extract that effectively inhibited M. smegmatis growth and biofilm formation. Biofilm quantification was performed by staining the biofilms with crystal violet and determining the amount of the stain using a spectrophotometer. In addition, the effects of combining the most active extract with kanamycin were also investigated.

RESULTS: The minimum inhibitory concentrations (MIC) of the extracts were found to be 6.2 μg/ml for the acetone extract, 12.5 μg/ml for both the ethanol and the total extract and 50 μg/ml for both the methanol and ethyl acetate extracts. The ethanol extract, dichloromethane extract and water extract were the only extracts that effectively inhibited biofilm formation in M. smegmatis. Combining the ethanol extract with kanamycin enhanced the effect of the ethanol extract in terms of inhibition of biofilm formation.

CONCLUSIONS: P. curatellifolia leaves contain phytochemicals that have the potential to be used both as antimycobacterial and anti-biofilm formation compounds.}, } @article {pmid28557053, year = {2017}, author = {Cuevas, RA and Eutsey, R and Kadam, A and West-Roberts, JA and Woolford, CA and Mitchell, AP and Mason, KM and Hiller, NL}, title = {A novel streptococcal cell-cell communication peptide promotes pneumococcal virulence and biofilm formation.}, journal = {Molecular microbiology}, volume = {105}, number = {4}, pages = {554-571}, pmid = {28557053}, issn = {1365-2958}, support = {R00 DC011322/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Cell Communication/physiology ; Chinchilla ; Databases, Nucleic Acid ; Ear, Middle/microbiology ; Gene Expression Regulation, Bacterial/genetics ; Otitis Media/microbiology ; Peptides/metabolism ; Pneumococcal Infections/metabolism ; Sequence Analysis, DNA/methods ; Streptococcus/metabolism ; Streptococcus pneumoniae/genetics/*metabolism ; Virulence/*genetics ; Virulence Factors/genetics/metabolism ; }, abstract = {Streptococcus pneumoniae (pneumococcus) is a major human pathogen. It is a common colonizer of the human respiratory track, where it utilizes cell-cell communication systems to coordinate population-level behaviors. We reasoned that secreted peptides that are highly expressed during infection are pivotal for virulence. Thus, we used in silico pattern searches to define a pneumococcal secretome and analyzed the transcriptome of the clinically important PMEN1 lineage to identify which peptide-encoding genes are highly expressed in vivo. In this study, we characterized virulence peptide 1 (vp1), a highly expressed Gly-Gly peptide-encoding gene in chinchilla middle ear effusions. The vp1 gene is widely distributed across pneumococcus as well as encoded in related species. Studies in the chinchilla model of middle ear infection demonstrated that VP1 is a virulence determinant. The vp1 gene is positively regulated by a transcription factor from the Rgg family and its cognate SHP (short hydrophobic peptide). In vitro data indicated that VP1 promotes increased thickness and biomass for biofilms grown on chinchilla middle ear epithelial cells. Furthermore, the wild-type biofilm is restored with the exogenous addition of synthetic VP1. We conclude that VP1 is a novel streptococcal regulatory peptide that controls biofilm development and pneumococcal pathogenesis.}, } @article {pmid28555174, year = {2017}, author = {Liu, Q and Wang, X and Qin, J and Cheng, S and Yeo, WS and He, L and Ma, X and Liu, X and Li, M and Bae, T}, title = {The ATP-Dependent Protease ClpP Inhibits Biofilm Formation by Regulating Agr and Cell Wall Hydrolase Sle1 in Staphylococcus aureus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {181}, pmid = {28555174}, issn = {2235-2988}, support = {R21 AI121664/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Autolysis ; Bacterial Proteins/*drug effects/genetics/metabolism ; Biofilms/*drug effects ; Cell Wall/*drug effects/metabolism ; Disease Models, Animal ; Endopeptidase Clp/*antagonists & inhibitors/genetics/physiology ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Bacterial/genetics ; Hydrolases/*drug effects/metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Mutation ; Staphylococcus aureus/*drug effects/pathogenicity/physiology ; Trans-Activators/*drug effects/metabolism ; Virulence/genetics ; }, abstract = {Biofilm causes hospital-associated infections on indwelling medical devices. In Staphylococcus aureus, Biofilm formation is controlled by intricately coordinated network of regulating systems, of which the ATP-dependent protease ClpP shows an inhibitory effect. Here, we demonstrate that the inhibitory effect of ClpP on biofilm formation is through Agr and the cell wall hydrolase Sle1. Biofilm formed by clpP mutant consists of proteins and extracellular DNA (eDNA). The increase of the protein was, at least in part, due to the reduced protease activity of the mutant, which was caused by the decreased activity of agr. On the other hand, the increase of eDNA was due to increased cell lysis caused by the higher level of Sle1. Indeed, as compared with wild type, the clpP mutant excreted an increased level of eDNA, and showed higher sensitivity to Triton-induced autolysis. The deletion of sle1 in the clpP mutant decreased the biofilm formation, the level of eDNA, and the Triton-induced autolysis to wild-type levels. Despite the increased biofilm formation capability, however, the clpP mutant showed significantly reduced virulence in a murine model of subcutaneous foreign body infection, indicating that the increased biofilm formation capability cannot compensate for the intrinsic functions of ClpP during infection.}, } @article {pmid28554609, year = {2017}, author = {Nedeljkovic, I and De Munck, J and Ungureanu, AA and Slomka, V and Bartic, C and Vananroye, A and Clasen, C and Teughels, W and Van Meerbeek, B and Van Landuyt, KL}, title = {Biofilm-induced changes to the composite surface.}, journal = {Journal of dentistry}, volume = {63}, number = {}, pages = {36-43}, doi = {10.1016/j.jdent.2017.05.015}, pmid = {28554609}, issn = {1879-176X}, mesh = {Acrylic Resins/chemistry ; Actinomyces/growth & development ; Bacterial Adhesion ; Biofilms/*growth & development ; Bisphenol A-Glycidyl Methacrylate/*chemistry ; Coculture Techniques ; Composite Resins/*chemistry ; DNA, Bacterial ; Dental Caries/microbiology ; Dental Materials/*chemistry ; Fusobacterium nucleatum/growth & development ; Humans ; Materials Testing ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Polyurethanes/chemistry ; Sterol Esterase ; Streptococcus mutans/growth & development ; Streptococcus sanguis/growth & development ; Surface Properties ; }, abstract = {OBJECTIVES: Composites may undergo biodegradation in the oral cavity. The objective was to investigate the effect of single- and multi-species biofilms on the surface roughness and topography of two composites.

METHODS: Disk-shaped specimens of a paste-like, Bis-GMA-free (Gradia Direct Anterior, GC), and a flowable, Bis-GMA-based composite (Tetric EvoFlow, Ivoclar-Vivadent) were prepared. After ethylene-oxide sterilization (38°C), specimens (n=3) were incubated with Streptococcus mutans or mixed bacterial culture (Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum). As negative controls, unexposed specimens and specimens exposed to sterile medium (BHI) were used. Specimens exposed to acidified BHI medium (pH=5) and enzymatic solution of cholesterol esterase served as positive control. Following 6-week incubation, the attached biofilms were collected for real-time PCR assessment, after which the surface roughness and topography of the specimens were analyzed with atomic force microscopy. Surface hydrophilicity/hydrophobicity was determined by contact angle measurements. Biofilm structure was analyzed with scanning electron microscopy.

RESULTS: Even though multi-species biofilms were thicker, with more cells attached, they did not significantly affect the surface roughness of the composites. On the other hand, S. mutans alone significantly increased the roughness of Tetric by 40.3%, while its effect on Gradia was lower (12%). The total amount of attached bacteria, however, did not differ between the composites.

CONCLUSIONS: S. mutans can increase the surface roughness of composites, depending on their composition. This ability of S. mutans is, however, mitigated in co-culture with other species. In particular, bacterial esterases seem to be responsible for the increased composite surface roughness upon biofilms exposure.

CLINICAL SIGNIFICANCE: Cariogenic bacteria can degrade composites, thereby increasing the surface roughness. Increased roughness and subsequent improved bacterial accumulation may facilitate the development of secondary caries around composites, which is the most common reason for the restoration failure.}, } @article {pmid28554093, year = {2017}, author = {Park, JS and Ryu, EJ and Li, L and Choi, BK and Kim, BM}, title = {New bicyclic brominated furanones as potent autoinducer-2 quorum-sensing inhibitors against bacterial biofilm formation.}, journal = {European journal of medicinal chemistry}, volume = {137}, number = {}, pages = {76-87}, doi = {10.1016/j.ejmech.2017.05.037}, pmid = {28554093}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Furans/chemical synthesis/*pharmacology ; Fusobacterium nucleatum/drug effects ; Homoserine/*analogs & derivatives/antagonists & inhibitors ; Lactones/*antagonists & inhibitors ; Microbial Sensitivity Tests ; Molecular Structure ; Porphyromonas gingivalis/drug effects ; Quorum Sensing/drug effects ; Structure-Activity Relationship ; Tannerella forsythia/drug effects ; }, abstract = {Bacterial behaviors such as virulence factor secretion and biofilm formation are critical for survival, and are effectively regulated through quorum sensing, a mechanism of intra- and interspecies communication in response to changes in cell density and species complexity. Many bacterial species colonize host tissues and form a defensive structure called a biofilm, which can be the basis of inflammatory diseases. Periodontitis, a chronic inflammatory disease affecting the periodontium, is caused by subgingival biofilms related to periodontopathogens. In particular, Fusobacterium nucleatum is a major co-aggregation bridge organism in the formation and growth of subgingival biofilms, linking the early and late colonizers in periodontal biofilms. According to our previous study, the intergeneric quorum-sensing signal molecule autoinducer-2 (AI-2) of F. nucleatum plays a key role in intra- and interspecies interactions of periodontopathogens, and may be a good target for periodontal biofilm inhibition. Recently, brominated furanones produced by the macroalga Delisea pulchra were shown to inhibit biofilm formation via AI-2, and have been investigated toward the goal of increasing the inhibition effect. In this study, we describe the synthesis of new bromofuranone analogs, i.e., 3-(dibromomethylene)isobenzofuran-1(3H)-one derivatives, and demonstrate their inhibitory activities against biofilm formation by periodontopathogens, including F. nucleatum, Porphyromonas gingivalis, and Tannerella forsythia.}, } @article {pmid28554028, year = {2017}, author = {McArthur, JV and Dicks, CA and Bryan, AL and Tuckfield, RC}, title = {The effects of low-level ionizing radiation and copper exposure on the incidence of antibiotic resistance in lentic biofilm bacteria.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {228}, number = {}, pages = {390-397}, doi = {10.1016/j.envpol.2017.03.081}, pmid = {28554028}, issn = {1873-6424}, mesh = {Bacteria/drug effects/genetics/radiation effects ; Biofilms/*drug effects/*radiation effects ; Copper/*toxicity ; Drug Resistance, Bacterial/*drug effects/genetics/*radiation effects ; Incidence ; *Radiation, Ionizing ; Water Pollutants/*toxicity ; }, abstract = {Environmental reservoirs of antibiotic resistant bacteria are poorly understood. Understanding how the environment selects for resistance traits in the absence of antibiotics is critical in developing strategies to mitigate this growing menace. Indirect or co-selection of resistance by environmental pollution has been shown to increase antibiotic resistance. However no attention has been given to the effects of low-level ionizing radiation or the interactions between radiation and heavy metals on the maintenance or selection for antibiotic resistance (AR) traits. Here we explore the effect of radiation and copper on antibiotic resistance. Bacteria were collected from biofilms in two ponds - one impacted by low-level radiocesium and the other an abandoned farm pond. Through laboratory controlled experiments we examined the effects of increasing concentrations of copper on the incidence of antibiotic resistance. Differences were detected in the resistance profiles of the controls from each pond. Low levels (0.01 mM) of copper sulfate increased resistance but 0.5 mM concentrations of copper sulfate depressed the AR response in both ponds. A similar pattern was observed for levels of multiple antibiotic resistance per isolate. The first principal component response of isolate exposure to multiple antibiotics showed significant differences among the six isolate treatment combinations. These differences were clearly visualized through a discriminant function analysis, which showed distinct antibiotic resistance response patterns based on the six treatment groups.}, } @article {pmid28552832, year = {2017}, author = {Aires, CP and Batista, MJA and Pitondo-Silva, A}, title = {Decrease of ceftriaxone susceptibility in Klebsiella pneumoniae according to biofilm maturation.}, journal = {Journal of global antimicrobial resistance}, volume = {9}, number = {}, pages = {126-127}, doi = {10.1016/j.jgar.2017.05.001}, pmid = {28552832}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Ceftriaxone/*pharmacology ; *Drug Tolerance ; Humans ; Klebsiella pneumoniae/*drug effects/*growth & development ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, } @article {pmid28552808, year = {2017}, author = {Noumi, E and Snoussi, M and Merghni, A and Nazzaro, F and Quindós, G and Akdamar, G and Mastouri, M and Al-Sieni, A and Ceylan, O}, title = {Phytochemical composition, anti-biofilm and anti-quorum sensing potential of fruit, stem and leaves of Salvadora persica L. methanolic extracts.}, journal = {Microbial pathogenesis}, volume = {109}, number = {}, pages = {169-176}, doi = {10.1016/j.micpath.2017.05.036}, pmid = {28552808}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Chromobacterium/drug effects ; Fruit/*chemistry ; Indoles/metabolism ; Methanol ; Microbial Sensitivity Tests ; Phytochemicals/*pharmacology ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Plant Stems/*chemistry ; Polymethyl Methacrylate ; Polyphenols/chemistry/isolation & purification/pharmacology ; Polystyrenes ; Pseudomonas aeruginosa/drug effects ; Quorum Sensing/*drug effects ; Salvadoraceae/*chemistry ; Staphylococcal Infections/prevention & control ; Staphylococcus/drug effects/growth & development/pathogenicity ; Yemen ; }, abstract = {Emergence of antibiotic resistance among pathogenic bacteria encourages us to search for new molecules as an alternative treatment. The aim of this study was to evaluate the antiquorum sensing (anti-QS) and antibiofilm potential of Salvadora persica L. methanolic extracts to prevent the infections due to Staphylococcus as an alternate to antibiotics. The methanolic extracts of S. persica L. fruit, leaves and stems was assessed for their activity in inhibiting QS-depedent phenomenon such as violacein pigment production in Chromobacterium violaceum, swarming motility of Pseudomonas aeruginosa PAO1 and biofilm formation in oral Staphylococcus strains on polymethylmetacrylate (PMMA). Methanolic fruit extract of S. persica L. showed a high degree of anti-biofilm formation on PMMA and on violacein inhibition with a percentage of reduction equal to 90% when MIC value (20 mg/ml) was used. 100 μg/ml of S. persica L. leaves exhibited inhibition in swarming motility of PAO1 at 29.17%. Because the methanolic extracts of S. persica L. demonstrated anti-QS and antibiofilm activity at very low concentrations, it could be further exploited for novel molecules to treat oral Staphylococcus infections.}, } @article {pmid28551023, year = {2017}, author = {Alfa, MJ and Ribeiro, MM and da Costa Luciano, C and Franca, R and Olson, N and DeGagne, P and Singh, H}, title = {A novel polytetrafluoroethylene-channel model, which simulates low levels of culturable bacteria in buildup biofilm after repeated endoscope reprocessing.}, journal = {Gastrointestinal endoscopy}, volume = {86}, number = {3}, pages = {442-451.e1}, doi = {10.1016/j.gie.2017.05.014}, pmid = {28551023}, issn = {1097-6779}, mesh = {*Biofilms ; Colony Count, Microbial ; *Disinfectants ; Disinfection/*methods ; Endoscopes ; Endoscopes, Gastrointestinal/*microbiology ; Enterococcus faecalis/*growth & development/isolation & purification ; Equipment Contamination ; *Glutaral ; Humans ; Microbial Viability ; Microscopy, Electron, Scanning ; Models, Biological ; *Polytetrafluoroethylene ; Pseudomonas aeruginosa/*growth & development/isolation & purification ; }, abstract = {BACKGROUND AND AIMS: Clinical studies have shown variable culture results from flexible endoscope channels possibly because of low levels of bacteria that are difficult to extract. The aim of this study was to develop a simulated-use buildup biofilm (BBF) model that mimics low levels of viable bacteria after repeated rounds of aldehyde fixation and accumulation.

METHODS: New endoscope channels were exposed to 8 days of repeated rounds of biofilm formation using ATS2015 containing Enterococcus faecalis and Pseudomonas aeruginosa, rinsing, fixation with glutaraldehyde, and rinsing. Viable count and scanning electron microscopy and borescope examination were used to compare the impact of dry storage over 26 weeks on the level of culturable bacteria and to compare the Centers for Disease Control and Prevention flush method of channel harvesting with a flush-brush-flush method.

RESULTS: E faecalis (log10 6.6) and P aeruginosa (log10 8.6) accumulated over 8 days of cyclic biofilm formation and partial glutaraldehyde fixation, but after a final exposure to 2.6% glutaraldehyde the level of culturable bacteria was less than 2 log10. The Centers for Disease Control and Prevention channel harvesting method appeared by borescope to be inferior to a flush-brush-flush sample collection method for detection of viable bacteria. P aeruginosa increased up to 7 log10 after 26 weeks of dry storage, indicating there were viable but nonculturable bacteria present initially that recovered during storage.

CONCLUSIONS: Viable but nonculturable P aeruginosa within the BBF model are able to recover, and this phenomenon may explain the variability of culture in patient-used endoscopes. Our data also indicated that friction may be a critical part of sample collection from endoscope channels.}, } @article {pmid28550056, year = {2017}, author = {Marti, R and Schmid, M and Kulli, S and Schneeberger, K and Naskova, J and Knøchel, S and Ahrens, CH and Hummerjohann, J}, title = {Biofilm Formation Potential of Heat-Resistant Escherichia coli Dairy Isolates and the Complete Genome of Multidrug-Resistant, Heat-Resistant Strain FAM21845.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {15}, pages = {}, pmid = {28550056}, issn = {1098-5336}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms ; Cattle ; Dairy Products/*microbiology ; Dairying ; *Drug Resistance, Bacterial ; Escherichia coli/drug effects/genetics/*isolation & purification/*physiology ; Escherichia coli Proteins/genetics/metabolism ; Food Contamination/analysis ; *Genome, Bacterial ; Hot Temperature ; }, abstract = {We tested the biofilm formation potential of 30 heat-resistant and 6 heat-sensitive Escherichia coli dairy isolates. Production of curli and cellulose, static biofilm formation on polystyrene (PS) and stainless steel surfaces, biofilm formation under dynamic conditions (Bioflux), and initial adhesion rates (IAR) were evaluated. Biofilm formation varied greatly between strains, media, and assays. Our results highlight the importance of the experimental setup in determining biofilm formation under conditions of interest, as correlation between different assays was often not a given. The heat-resistant, multidrug-resistant (MDR) strain FAM21845 showed the strongest biofilm formation on PS and the highest IAR and was the only strain that formed significant biofilms on stainless steel under conditions relevant to the dairy industry, and it was therefore fully sequenced. Its chromosome is 4.9 Mb long, and it harbors a total of five plasmids (147.2, 54.2, 5.8, 2.5, and 1.9 kb). The strain carries a broad range of genes relevant to antimicrobial resistance and biofilm formation, including some on its two large conjugative plasmids, as demonstrated in plate mating assays.IMPORTANCE In biofilms, cells are embedded in an extracellular matrix that protects them from stresses, such as UV radiation, osmotic shock, desiccation, antibiotics, and predation. Biofilm formation is a major bacterial persistence factor of great concern in the clinic and the food industry. Many tested strains formed strong biofilms, and especially strains such as the heat-resistant, MDR strain FAM21845 may pose a serious issue for food production. Strong biofilm formation combined with diverse resistances (some encoded on conjugative plasmids) may allow for increased persistence, coselection, and possible transfer of these resistance factors. Horizontal gene transfer may conceivably occur in the food production setting or the gastrointestinal tract after consumption.}, } @article {pmid28549926, year = {2017}, author = {Gholami, S and Tabatabaei, M and Sohrabi, N}, title = {Comparison of biofilm formation and antibiotic resistance pattern of Pseudomonas aeruginosa in human and environmental isolates.}, journal = {Microbial pathogenesis}, volume = {109}, number = {}, pages = {94-98}, doi = {10.1016/j.micpath.2017.05.004}, pmid = {28549926}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Ceftazidime/pharmacology ; DNA, Bacterial ; Drug Resistance, Bacterial/*genetics ; *Environmental Microbiology ; Genes, Bacterial/genetics ; Gentamicins/pharmacology ; Humans ; Meropenem ; Microbial Sensitivity Tests ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/*genetics/*isolation & purification/*physiology ; RNA, Ribosomal, 16S/genetics ; Sigma Factor/genetics ; Soil Microbiology ; Thienamycins/pharmacology ; Water Microbiology ; }, abstract = {Pseudomonas aeruginosa is an opportunistic human pathogen especially in patients with underlying diseases such as cyctic fibrosis and has been established as a model organism to study bacterial biofilm formation. The aim of this study was to compare the biofilm formation and antibiotic resistance in human and environmental P. aeruginosa isolates. Numbers of positive samples for algD and algU genes in human samples were 98% and the positive samples for algD and algU genes in the environmental samples were 80% and 70%, respectively. Ability to create biofilms by the human and environmental samples were 70% and 28%, respectively. The incidences of various antibiotic resistance genes in human samples including blaTEM and blaSHV were 92% and 16%, respectively but antibiotic resistance genes in environmental samples including blaTEM and blaSHV were 20% and 6%, respectively. High resistance to gentamicin (74%) and meropenem (70%), were found in the human samples, were as in the environmental samples high level of resistance were observed to ceftazidime (30%), gentamicin and meropenem (28%). According to findings of this study, differences in genes involve in biofilm synthesis between human and environmental isolates are highly significant and the environmental isolates of P. aeruginosa stile are sensitive to most antibiotics because they lacks the antibiotic resistance genes. But after transfer to human and isolation from diseased people have been taken the antibiotic resistance genes that would be resistant to many antibiotics.}, } @article {pmid28549260, year = {2017}, author = {Khalid, M and Hassani, D and Bilal, M and Butt, ZA and Hamayun, M and Ahmad, A and Huang, D and Hussain, A}, title = {Identification of oral cavity biofilm forming bacteria and determination of their growth inhibition by Acacia arabica, Tamarix aphylla L. and Melia azedarach L. medicinal plants.}, journal = {Archives of oral biology}, volume = {81}, number = {}, pages = {175-185}, doi = {10.1016/j.archoralbio.2017.05.011}, pmid = {28549260}, issn = {1879-1506}, mesh = {*Acacia ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/isolation & purification ; Biofilms/*drug effects ; Humans ; *Melia azedarach ; Mouth/*microbiology ; Phylogeny ; Plant Extracts/*pharmacology ; Polymerase Chain Reaction ; *Tamaricaceae ; }, abstract = {OBJECTIVE: Biofilms are complex, multi-species bacterial communities that colonize the oral cavity in the form of plaque and are known to cause dental caries and periodontal disease. Present study demonstrated the potential of three selected medicinal plants against isolated and identified dental biofilm forming strains.

METHODS: Pathogenic bacteria from dental biofilms were isolated, cultured, identified by phylogenetic analysis using PCR-based 16S ribosomal RNA (or 16S rRNA) nucleotide sequences and were analyzed for their biofilm forming capability. The antimicrobial activity of the three important medicinal plant extracts (Acacia arabica, Tamarix aphylla L. and Melia azadirachta L.) was determined against the highest biofilm forming bacteria.

RESULTS: Phylogenetic analysis revealed that the 19 strains belonged to Proteobacteria, Firmicutes and Actinobacteria. Among the 19 isolates, eleven strains were found to possess high biofilm formation capability comparatively and antimicrobial activity assay showed that the selected plants considerably inhibited their growth. Extract from A. arabica stem had strong effect on the ability of bacteria isolated from dental carries as evident by up to 73% reduction in biofilm formation on surface pre-treated with extract from this plant. The same extract also showed tremendous biofilm cleaning potential up to 87% of the biofilm.

CONCLUSION: The results suggested that the extracts of selected medicinal plants could be used for protection against pathogenic dental biofilm causing bacteria and attempts should be taken by pharmaceutical industries to utilize it in dental caring products.}, } @article {pmid28549255, year = {2017}, author = {Tang, B and Song, H and Bin, L and Huang, S and Zhang, W and Fu, F and Zhao, Y and Chen, Q}, title = {Determination of the profile of DO and its mass transferring coefficient in a biofilm reactor packed with semi-suspended bio-carriers.}, journal = {Bioresource technology}, volume = {241}, number = {}, pages = {54-62}, doi = {10.1016/j.biortech.2017.05.071}, pmid = {28549255}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Hydrodynamics ; }, abstract = {The work aims at illustrating the profile of DO and its mass transferring process in a biofilm reactor packed with a novel semi-suspended bio-carrier, and further revealing the main factors that influence the mass transferring coefficient of DO within the biofilm. Results showed that the biofilm was very easy to attach and grow on the semi-suspended bio-carrier, which obviously changed the DO profile inside and outside the biofilm. The semi-suspended bio-carrier caused three different mass transfer zones occurring in the bioreactor, including the zones of bulk solution, boundary layer and biofilm, in which, the boundary layer zone had an obvious higher mass transfer resistance. Increasing the aeration rate might improve the hydrodynamic conditions in the bioreactor and accelerate the mass transfer of DO, but it also detached the biofilm from the surface of bio-carrier, which reduced the consumption of DO, and accordingly, decreased the DO gradient in the bioreactor.}, } @article {pmid28548604, year = {2017}, author = {Zúñiga, A and Donoso, RA and Ruiz, D and Ruz, GA and González, B}, title = {Quorum-Sensing Systems in the Plant Growth-Promoting Bacterium Paraburkholderia phytofirmans PsJN Exhibit Cross-Regulation and Are Involved in Biofilm Formation.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {30}, number = {7}, pages = {557-565}, doi = {10.1094/MPMI-01-17-0008-R}, pmid = {28548604}, issn = {0894-0282}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Arabidopsis/*growth & development/microbiology ; *Biofilms ; Burkholderia/*genetics/metabolism/physiology ; Gene Expression Profiling/methods ; Gene Expression Regulation, Bacterial ; Gene Regulatory Networks ; Host-Pathogen Interactions ; Models, Genetic ; Mutation ; Plant Roots/*growth & development/microbiology ; Quorum Sensing/*genetics ; }, abstract = {Quorum-sensing systems play important roles in host colonization and host establishment of Burkholderiales species. Beneficial Paraburkholderia species share a conserved quorum-sensing (QS) system, designated BraI/R, that controls different phenotypes. In this context, the plant growth-promoting bacterium Paraburkholderia phytofirmans PsJN possesses two different homoserine lactone QS systems BpI.1/R.1 and BpI.2/R.2 (BraI/R-like QS system). The BpI.1/R.1 QS system was previously reported to be important to colonize and produce beneficial effects in Arabidopsis thaliana plants. Here, we analyzed the temporal variations of the QS gene transcript levels in the wild-type strain colonizing plant roots. The gene expression patterns showed relevant differences in both QS systems compared with the wild-type strain in the unplanted control treatment. The gene expression data were used to reconstruct a regulatory network model of QS systems in P. phytofirmans PsJN, using a Boolean network model. Also, we examined the phenotypic traits and transcript levels of genes involved in QS systems, using P. phytofirmans mutants in homoserine lactone synthases genes. We observed that the BpI.1/R.1 QS system regulates biofilm formation production in strain PsJN and this phenotype was associated with the lower expression of a specific extracytoplasmic function sigma factor ecf26.1 gene (implicated in biofilm formation) in the bpI.1 mutant strain.}, } @article {pmid28548373, year = {2017}, author = {Shanmugam, M and Oyeniyi, AO and Parthiban, C and Gujjarlapudi, SK and Pier, GB and Ramasubbu, N}, title = {Role of de-N-acetylase PgaB from Aggregatibacter actinomycetemcomitans in exopolysaccharide export in biofilm mode of growth.}, journal = {Molecular oral microbiology}, volume = {32}, number = {6}, pages = {500-510}, pmid = {28548373}, issn = {2041-1014}, support = {R01 DE022544/DE/NIDCR NIH HHS/United States ; }, mesh = {Acetylesterase/*genetics/*physiology ; Acetylglucosamine/immunology/metabolism ; Aggregatibacter actinomycetemcomitans/*enzymology/*genetics/*metabolism/pathogenicity ; Bacterial Proteins/genetics/physiology ; Biofilms/growth & development ; Catalytic Domain ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/*genetics ; Open Reading Frames/genetics ; Operon ; Periodontitis ; Polysaccharides, Bacterial ; Sequence Deletion ; Virulence/genetics ; }, abstract = {Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, is the causative agent of localized aggressive periodontitis. Attachment to a biotic surface is a critical first step in the A. actinomycetemcomitans infection process for which exopolysaccharides have been shown to be essential. In addition, the pga operon, containing genes encoding for biosynthetic proteins for poly-N-acetyl glucosamine (PNAG), plays a key role in A. actinomycetemcomitans virulence, as a mutant strain lacking the pga operon induces significantly less bone resorption. Among the genes in the pga operon, pgaB codes for a de-N-acetylase that is responsible for the deacetylation of the PNAG exopolysaccharide. Here we report the role of PgaB in regulation of virulence genes using a markerless, scarless deletion mutant targeting the coding region of the N-terminal catalytic domain of PgaB. The results demonstrate that the N-terminal, catalytic domain of PgaB is crucial for exopolysaccharide export.}, } @article {pmid28546427, year = {2017}, author = {Hobley, L and Li, B and Wood, JL and Kim, SH and Naidoo, J and Ferreira, AS and Khomutov, M and Khomutov, A and Stanley-Wall, NR and Michael, AJ}, title = {Spermidine promotes Bacillus subtilis biofilm formation by activating expression of the matrix regulator slrR.}, journal = {The Journal of biological chemistry}, volume = {292}, number = {29}, pages = {12041-12053}, pmid = {28546427}, issn = {1083-351X}, support = {BB/1019464/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adenosylmethionine Decarboxylase/genetics/metabolism ; Bacillus subtilis/cytology/genetics/growth & development/*physiology ; Bacterial Proteins/*agonists/genetics/metabolism ; Biofilms/*growth & development ; Cadaverine/analogs & derivatives/metabolism ; Gene Deletion ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Methionine/metabolism ; Methylation ; Nitrogen Cycle ; Operon ; Polysaccharides, Bacterial/*biosynthesis ; Purines/metabolism ; S-Adenosylmethionine/metabolism ; Single-Cell Analysis ; Spermidine/analogs & derivatives/*metabolism ; Transcription Factors/*agonists/genetics/metabolism ; }, abstract = {Ubiquitous polyamine spermidine is not required for normal planktonic growth of Bacillus subtilis but is essential for robust biofilm formation. However, the structural features of spermidine required for B. subtilis biofilm formation are unknown and so are the molecular mechanisms of spermidine-stimulated biofilm development. We report here that in a spermidine-deficient B. subtilis mutant, the structural analogue norspermidine, but not homospermidine, restored biofilm formation. Intracellular biosynthesis of another spermidine analogue, aminopropylcadaverine, from exogenously supplied homoagmatine also restored biofilm formation. The differential ability of C-methylated spermidine analogues to functionally replace spermidine in biofilm formation indicated that the aminopropyl moiety of spermidine is more sensitive to C-methylation, which it is essential for biofilm formation, but that the length and symmetry of the molecule is not critical. Transcriptomic analysis of a spermidine-depleted B. subtilis speD mutant uncovered a nitrogen-, methionine-, and S-adenosylmethionine-sufficiency response, resulting in repression of gene expression related to purine catabolism, methionine and S-adenosylmethionine biosynthesis and methionine salvage, and signs of altered membrane status. Consistent with the spermidine requirement in biofilm formation, single-cell analysis of this mutant indicated reduced expression of the operons for production of the exopolysaccharide and TasA protein biofilm matrix components and SinR antagonist slrR Deletion of sinR or ectopic expression of slrR in the spermidine-deficient ΔspeD background restored biofilm formation, indicating that spermidine is required for expression of the biofilm regulator slrR Our results indicate that spermidine functions in biofilm development by activating transcription of the biofilm matrix exopolysaccharide and TasA operons through the regulator slrR.}, } @article {pmid28544990, year = {2017}, author = {Escolà Casas, M and Nielsen, TK and Kot, W and Hansen, LH and Johansen, A and Bester, K}, title = {Degradation of mecoprop in polluted landfill leachate and waste water in a moving bed biofilm reactor.}, journal = {Water research}, volume = {121}, number = {}, pages = {213-220}, doi = {10.1016/j.watres.2017.05.031}, pmid = {28544990}, issn = {1879-2448}, mesh = {2-Methyl-4-chlorophenoxyacetic Acid/*analogs & derivatives ; Biofilms ; *Bioreactors ; Wastewater ; *Water Pollutants, Chemical ; Water Purification ; }, abstract = {Mecoprop is a common pollutant in effluent-, storm- and groundwater as well as in leachates from derelict dumpsites. Thus, bioremediation approaches may be considered. We conducted batch experiments with moving bed biofilm (MBBR)-carriers to understand the degradation of mecoprop. As a model, the carriers were incubated in effluent from a conventional wastewater treatment plant which was spiked to 10, 50 and 100 μg L[-1] mecoprop. Co-metabolic processes as well as mineralization were studied. Initial mecoprop concentration and mecoprop degradation impacted the microbial communities. The removal of (S)-mecoprop prevailed over the (R)-mecoprop. This was associated with microbial compositions, in which several operational taxonomic units (OTUs) co-varied positively with (S)-mecoprop removal. The removal-rate constant of (S)-mecoprop was 0.5 d[-1] in the 10 μg L[-1] set-up but it decreased in the 50 and 100 μg L[-1] set-ups. The addition of methanol prolonged the removal of (R)-mecoprop. During mecoprop degradation, 4-chloro-2-methylphenol was formed and degraded. A new metabolite (4-chloro-2-methylphenol sulfate) was identified and quantified.}, } @article {pmid28544960, year = {2017}, author = {Dalcin, AJF and Santos, CG and Gündel, SS and Roggia, I and Raffin, RP and Ourique, AF and Santos, RCV and Gomes, P}, title = {Anti biofilm effect of dihydromyricetin-loaded nanocapsules on urinary catheter infected by Pseudomonas aeruginosa.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {156}, number = {}, pages = {282-291}, doi = {10.1016/j.colsurfb.2017.05.029}, pmid = {28544960}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Flavonols/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Nanocapsules/*chemistry ; Particle Size ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects ; Urinary Catheters/microbiology ; }, abstract = {Nosocomial infections associated with biofilm formation on urinary catheters are among the leading causes of complications due to biofilm characteristics and high antimicrobial resistance. An interesting alternative are natural products, such as Dihydromyricetin (DMY), a flavonoid which presents several pharmacological properties, including strong antimicrobial activity against various microorganisms. However, DMY, has low aqueous solubility and consequently low bioavailability. Nanoencapsulation can contribute to the improvement of characteristics of some drugs, by increasing the apparent solubility and sustained release has been reported among other advantages. The aim of this study was to evaluate, for the first time, the feasibility of DMY nanoencapsulation, and to look at its influence on nanoencapsulation of DMY as well as verify its influence on antimicrobial and antibiofilm activity on urinary catheters infected by Pseudomonas aeruginosa. The physicochemical characterization showed an average diameter less than 170nm, low polydispersity index, positive zeta potential (between +11 and +14mV), slightly acidic pH. The values of the stability study results showed that the best condition for suspension storage without losing physical and chemical characteristics was under refrigeration (4±2°C). The antibiofilm activity of the formulations resulted in the eradication of biofilms both in free DMY formulations and in nanocapsules of DMY during those periods. However, within 96h the results of the inhibition of biofilm by DMY nanocapsules were more effective compared with free DMY. Thus, the nanocapsule formulation containing DMY can potentially be used as an innovative approach to urinary catheter biofilm treatment or prevention.}, } @article {pmid28544612, year = {2017}, author = {Hoque, E and Fritscher, J}, title = {Ecology, adaptation, and function of methane-sulfidic spring water biofilm microorganisms, including a strain of anaerobic fungus Mucor hiemalis.}, journal = {MicrobiologyOpen}, volume = {6}, number = {4}, pages = {}, pmid = {28544612}, issn = {2045-8827}, mesh = {Anaerobiosis ; Archaea/classification/growth & development/*isolation & purification ; Bacteria/classification/growth & development/*isolation & purification ; Biofilms/growth & development ; *Biota ; Ciliophora/classification/growth & development/*isolation & purification ; Fungi/classification/growth & development/*isolation & purification ; Germany ; Methane/analysis ; Natural Springs/chemistry/*microbiology ; Sulfides/analysis ; Temperature ; }, abstract = {Ecological aspects, adaptation, and some functions of a special biofilm and its unique key anaerobic fungus Mucor hiemalis strain EH11 isolated from a pristine spring (Künzing, Bavaria, Germany) are described. The spring's pure nature is characterized by, for example, bubbling methane, marine-salinity, mild hydrothermal (~19.1°C), sulfidic, and reductive-anoxic (Eh : -241 to -253 mV, O2 : ≤ 0.1 mg/L) conditions. It is geoecologically located at the border zone between Bavarian Forest (crystalline rocky mountains) and the moor-like Danube River valley, where geological displacements bring the spring's water from the deeper layers of former marine sources up to the surface. In the spring's outflow, a special biofilm with selective microorganisms consisting of archaea, bacteria, protozoa (ciliate), and fungus was found. Typical sulfidic-spring bryophyta and macrozoobenthos were missing, but many halo- and anaerotolerant diatoms and ciliate Vorticella microstoma beside EH11 were identified. Phase contrast and scanning electron microscopy revealed the existence of a stabilizing matrix in the biofilm formed by the sessile fungal hyphae and the exopolysaccharide substance (EPS) structures, which harbors other microorganisms. In response to ecological adaptation pressure caused by methane bubbles, EH11 developed an atypical spring-like hyphal morphology, similar to the spiral stalk of ciliate V. microstoma, to rise up with methane bubbles. For the first time, it was also demonstrated that under strict anaerobic conditions EH11 changes its asexual reproduction process by forming pseudosporangia via hyphal cell divisions as well as switching its metabolism to chemoautotrophic bacteria-like anaerobic life using acetate as an e-donor and ferrihydrite as an e-acceptor, all without fermentation. EH11 can be suggested to be useful for the microbial community in the Künzing biofilm not only due to its physical stabilization of the biofilm's matrix but also due to its ecological functions in element recycling as well as a remover of toxic metals.}, } @article {pmid28542503, year = {2017}, author = {Létoffé, S and Chalabaev, S and Dugay, J and Stressmann, F and Audrain, B and Portais, JC and Letisse, F and Ghigo, JM}, title = {Biofilm microenvironment induces a widespread adaptive amino-acid fermentation pathway conferring strong fitness advantage in Escherichia coli.}, journal = {PLoS genetics}, volume = {13}, number = {5}, pages = {e1006800}, pmid = {28542503}, issn = {1553-7404}, mesh = {1-Propanol/metabolism ; *Adaptation, Physiological ; *Biofilms ; Escherichia coli/growth & development/*metabolism ; *Fermentation ; Oxygen/metabolism ; Threonine/*metabolism ; }, abstract = {Bacterial metabolism has been studied primarily in liquid cultures, and exploration of other natural growth conditions may reveal new aspects of bacterial biology. Here, we investigate metabolic changes occurring when Escherichia coli grows as surface-attached biofilms, a common but still poorly characterized bacterial lifestyle. We show that E. coli adapts to hypoxic conditions prevailing within biofilms by reducing the amino acid threonine into 1-propanol, an important industrial commodity not known to be naturally produced by Enterobacteriaceae. We demonstrate that threonine degradation corresponds to a fermentation process maintaining cellular redox balance, which confers a strong fitness advantage during anaerobic and biofilm growth but not in aerobic conditions. Whereas our study identifies a fermentation pathway known in Clostridia but previously undocumented in Enterobacteriaceae, it also provides novel insight into how growth in anaerobic biofilm microenvironments can trigger adaptive metabolic pathways edging out competition with in mixed bacterial communities.}, } @article {pmid28540581, year = {2017}, author = {Ionescu, AC and Hahnel, S and Cazzaniga, G and Ottobelli, M and Braga, RR and Rodrigues, MC and Brambilla, E}, title = {Streptococcus mutans adherence and biofilm formation on experimental composites containing dicalcium phosphate dihydrate nanoparticles.}, journal = {Journal of materials science. Materials in medicine}, volume = {28}, number = {7}, pages = {108}, pmid = {28540581}, issn = {1573-4838}, mesh = {Bacterial Adhesion/*physiology ; Biofilms/drug effects/*growth & development ; Calcium Phosphates/*administration & dosage/*chemistry ; Cell Survival/drug effects ; Nanocomposites/*chemistry/ultrastructure ; Resins, Synthetic/administration & dosage/*chemistry ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {UNLABELLED: This study aimed at evaluating bacterial adhesion and biofilm formation on resin-based composites (RBC) including dicalcium phosphate dihydrate nanoparticles (nDCPD).

METHODS: Specimens were prepared from experimental RBCs with BisGMA/TEGDMA resin matrix including 20 vol% of either nDCPD (nDCPD-RBC), TEGDMA-functionalized nDPCD (F-nDCPD-RBC) or silanized silica (SiO2-RBC). Neat resin blend (control-Resin), conventional nanohybrid RBC (control-RBC) and human enamel were used for reference. Characterization of the specimens included surface roughness (SR), surface free energy (SFE), chemical surface composition (EDS, XPS), and buffering ability of a pH = 4.00 solution. Streptococcus mutans adherence was assessed after 2 h; biofilm formation was simulated for 48 h using a bioreactor. Adherent, viable biomass was determined using tetrazolium salt assay (MTT).

RESULTS: nDCPD-RBC yielded highest roughness and showed higher polar and lower disperse component to total SFE. EDS and XPS indicated higher amounts of calcium and phosphate on the surface of nDCPD-RBC than on F-nDCPD-RBC. nDCPD buffered the acidic solution to 5.74, while functionalization almost prevented buffering (pH = 4.26). F-nDCPD-RBC reduced adherence and biofilm formation in comparison to nDCPD-RBC. Regardless of functionalization, biofilm formation on nDCPD-containing RBCs was not significantly different from SiO2-RBC. Control-Resin, control-RBC, and enamel surfaces showed similar adherence values as F-nDCPD-RBC, but lower biofilm formation compared to both nDCPD-containing RBCs. In conclusion, the incorporation of nDCPD did not minimize S. mutans adherence and biofilm formation as a function of the materials´ surface properties. However, results observed for the buffering capacity indicated that optimized formulations of biomimetic RBCs may be useful for modulating their interaction with microorganisms.}, } @article {pmid28540567, year = {2017}, author = {Scheuermann-Poley, C and Wagner, C and Hoffmann, J and Moter, A and Willy, C}, title = {[The significance of biofilm for the treatment of infections in orthopedic surgery : 2017 Update].}, journal = {Der Unfallchirurg}, volume = {120}, number = {6}, pages = {461-471}, pmid = {28540567}, issn = {1433-044X}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Bacterial Infections/*therapy ; Biofilms/*drug effects ; Combined Modality Therapy/methods ; Debridement/*methods ; Evidence-Based Medicine ; Humans ; Negative-Pressure Wound Therapy/*methods ; Orthopedic Procedures/*adverse effects ; Surgical Wound Infection/etiology/*therapy ; Treatment Outcome ; }, abstract = {BACKGROUND: The increase in endoprosthetic and osteosynthetic surgical treatment is associated with a simultaneous increase in implant-associated infections (surgical site infections, SSI). Biofilms appear to play a significant role in the diagnosis and treatment of these infections and heavily contaminated wounds. This article aims to provide a current overview of biofilm and its relevance in orthopedic surgery.

MATERIALS AND METHODS: A computer-assisted literature search of MedLine (PubMed) was performed using key word combinations with "biofilm" (as of March 2017).

RESULTS: Biofilm, a polymicrobial organization and life form surrounded by a polysaccharide matrix, refers to an adaptation strategy of bacteria in unfavorable living conditions (e. g. under antibiotic therapy). Biofilms can develop after 6 h in highly contaminated wounds. In acute and chronic infections, biofilms can occur in 30-80 % of the cases. Only planktonic bacteria (high metabolic activity, cultivable) can be detected in standard microbiological cultures, biofilms, however, cannot. Molecular microscopic methods, such as fluorescence in situ hybridization (FISH), enable the detection of bacteria in biofilms. The core concepts of anti-biofilm therapy include the prevention of biofilm and early surgical debridement, followed by the local and/or systemic administration of antibiotics as well as the local application of antiseptics.

CONCLUSIONS: The development of biofilm should be anticipated in strongly contaminated wounds as well as in acute and chronic infection sites. The best strategy to combat biofilms is to prevent their development. Standard microbiological culture methods do not enable the detection of biofilm. Therefore, the implementation of molecular biological detection methods (z. B. FISH) is important. Further anti-biofilm strategies are being investigated experimentally, but there are no real options for clinical use as of yet.}, } @article {pmid28537316, year = {2017}, author = {Edwards, GA and Shymanska, NV and Pierce, JG}, title = {5-Benzylidene-4-oxazolidinones potently inhibit biofilm formation in Methicillin-resistant Staphylococcus aureus.}, journal = {Chemical communications (Cambridge, England)}, volume = {53}, number = {53}, pages = {7353-7356}, pmid = {28537316}, issn = {1364-548X}, support = {R01 GM110154/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Benzylidene Compounds/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Oxazolidinones/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Investigation into the biological function of 5-benzylidene-4-oxazolidinones revealed dose-dependent inhibition of biofilm formation in Methicillin-resistant S. aureus (MRSA). This structurally unusual class of small molecules inhibit up to 89% of biofilm formation with IC50 values as low as 0.78 μM, and disperse pre-formed biofilms with IC50 values as low as 4.7 μM. Together, these results suggest that 4-oxazolidinones represent new chemotypes to enable the study of bacterial biofilms with small molecule chemical probes.}, } @article {pmid28536573, year = {2017}, author = {Sun, C and Guo, Y and Tang, K and Wen, Z and Li, B and Zeng, Z and Wang, X}, title = {MqsR/MqsA Toxin/Antitoxin System Regulates Persistence and Biofilm Formation in Pseudomonas putida KT2440.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {840}, pmid = {28536573}, issn = {1664-302X}, abstract = {Bacterial toxin/antitoxin (TA) systems have received increasing attention due to their prevalence, diverse structures, and important physiological functions. In this study, we identified and characterized a type II TA system in a soil bacterium Pseudomonas putida KT2440. This TA system belongs to the MqsR/MqsA family. We found that PP_4205 (MqsR) greatly inhibits cell growth in P. putida KT2440 and Escherichia coli, the antitoxin PP_4204 (MqsA) neutralizes the toxicity of the toxin MqsR, and the two genes encoding them are co-transcribed. MqsR and MqsA interact with each other directly in vivo and MqsA is a negative regulator of the TA operon through binding to the promoter. Consistent with the MqsR/MqsA pair in E. coli, the binding of the toxin MqsR to MqsA inhibits the DNA binding ability of MqsA in P. putida KT2440. Disruption of the mqsA gene which induces mqsR expression increases persister cell formation 53-fold, while overexpressing mqsA which represses mqsR expression reduces persister cell formation 220-fold, suggesting an important role of MqsR in persistence in P. putida KT2440. Furthermore, both MqsR and MqsA promote biofilm formation. As a DNA binding protein, MqsA can also negatively regulate an ECF sigma factor AlgU and a universal stress protein PP_3288. Thus, we revealed an important regulatory role of MqsR/MqsA in persistence and biofilm formation in P. putida KT2440.}, } @article {pmid28535844, year = {2017}, author = {Branchu, P and Canette, A and Medina Fernandez, S and Mounier, J and Meylheuc, T and Briandet, R and Grimaud, R and Naïtali, M}, title = {Impact of temperature on Marinobacter hydrocarbonoclasticus SP17 morphology and biofilm structure during growth on alkanes.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {5}, pages = {669-677}, doi = {10.1099/mic.0.000466}, pmid = {28535844}, issn = {1465-2080}, abstract = {Alkanes are widespread pollutants found in soil, freshwater and marine environments. Marinobacter hydrocarbonoclasticus (Mh) strain SP17 is a marine bacterium able to use many hydrophobic organic compounds, including alkanes, through the production of biofilms that allow their poor solubility to be overcome. This study pointed out that temperature is an environmental factor that strongly affects the biofilm formation and morphology of Mh on the model alkanes, hexadecane and paraffin. We showed that Mh biofilm formation and accumulation of intracytoplasmic inclusions are higher on solid alkanes (hexadecane at 10 °C and paraffin at 10 °C and 30 °C) than on liquid alkane (hexadecane at 30 °C) or soluble substrate (lactate at both temperatures). We also found that Mh produces more extracellular polymeric substances at 30 °C than at 10 °C on alkanes and none on lactate. We observed that bacterial length is significantly higher at 10 °C than at 30 °C on lactate and hexadecane. On paraffin, at 30 °C, the cell morphology is markedly altered by large rounded or irregularly shaped cytoplasmic inclusions. Altogether, the results showed that Mh is able to adapt and use alkanes as a carbon source, even at low temperature.}, } @article {pmid28535686, year = {2017}, author = {Tyler, BJ and Hook, A and Pelster, A and Williams, P and Alexander, M and Arlinghaus, HF}, title = {Development and characterization of a stable adhesive bond between a poly(dimethylsiloxane) catheter material and a bacterial biofilm resistant acrylate polymer coating.}, journal = {Biointerphases}, volume = {12}, number = {2}, pages = {02C412}, pmid = {28535686}, issn = {1559-4106}, mesh = {Acrylates/*chemistry ; Adhesives/*chemistry ; Biofilms/*growth & development ; Catheters/*microbiology ; Coated Materials, Biocompatible/*chemistry ; Dimethylpolysiloxanes/*chemistry ; Proteus mirabilis/*physiology ; Uropathogenic Escherichia coli/*physiology ; }, abstract = {Catheter associated urinary tract infections are the most common health related infections worldwide, contributing significantly to patient morbidity and mortality and increased health care costs. To reduce the incidence of these infections, new materials that resist bacterial biofilm formation are needed. A composite catheter material, consisting of bulk poly(dimethylsiloxane) (PDMS) coated with a novel bacterial biofilm resistant polyacrylate [ethylene glycol dicyclopentenyl ether acrylate (EGDPEA)-co-di(ethyleneglycol) methyl ether methacrylate (DEGMA)], has been proposed. The coated material shows excellent bacterial resistance when compared to commercial catheter materials, but delamination of the EGDPEA-co-DEGMA coatings under mechanical stress presents a challenge. In this work, the use of oxygen plasma treatment to improve the wettability and reactivity of the PDMS catheter material and improve adhesion with the EGDPEA-co-DEGMA coating has been investigated. Argon cluster three dimensional-imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to probe the buried adhesive interface between the EGDPEA-co-DEGMA coating and the treated PDMS. ToF-SIMS analysis was performed in both dry and frozen-hydrated states, and the results were compared to mechanical tests. From the ToF-SIMS data, the authors have been able to observe the presence of PDMS, silicates, salt particles, cracks, and water at the adhesive interface. In the dry catheters, low molecular weight PDMS oligomers at the interface were associated with poor adhesion. When hydrated, the hydrophilic silicates attracted water to the interface and led to easy delamination of the coating. The best adhesion results, under hydrated conditions, were obtained using a combination of 5 min O2 plasma treatment and silane primers. Cryo-ToF-SIMS analysis of the hydrated catheter material showed that the bond between the primed PDMS catheter and the EGDPEA-co-DEGMA coating was stable in the presence of water. The resulting catheter material resisted Escherichia coli and Proteus mirabilis biofilm colonization by up to 95% compared with uncoated PDMS after 10 days of continuous bacterial exposure and had the mechanical properties necessary for use as a urinary catheter.}, } @article {pmid28535292, year = {2017}, author = {Koza, A and Kusmierska, A and McLaughlin, K and Moshynets, O and Spiers, AJ}, title = {Adaptive radiation of Pseudomonas fluorescens SBW25 in experimental microcosms provides an understanding of the evolutionary ecology and molecular biology of A-L interface biofilm formation.}, journal = {FEMS microbiology letters}, volume = {364}, number = {12}, pages = {}, doi = {10.1093/femsle/fnx109}, pmid = {28535292}, issn = {1574-6968}, mesh = {Adaptation, Physiological/genetics ; Biofilms/*growth & development/radiation effects ; Biological Evolution ; Ecology ; Ecosystem ; Environment ; *Evolution, Molecular ; Genotype ; Mutation ; Phenotype ; Pseudomonas fluorescens/*genetics/physiology/*radiation effects ; Radiation ; }, abstract = {Combined experimental evolutionary and molecular biology approaches have been used to investigate the adaptive radiation of Pseudomonas fluorescens SBW25 in static microcosms leading to the colonisation of the air-liquid interface by biofilm-forming mutants such as the Wrinkly Spreader (WS). In these microcosms, the ecosystem engineering of the early wild-type colonists establishes the niche space for subsequent WS evolution and colonisation. Random WS mutations occurring in the developing population that deregulate diguanylate cyclases and c-di-GMP homeostasis result in cellulose-based biofilms at the air-liquid interface. These structures allow Wrinkly Spreaders to intercept O2 diffusing into the liquid column and limit the growth of competitors lower down. As the biofilm matures, competition increasingly occurs between WS lineages, and niche divergence within the biofilm may support further diversification before system failure when the structure finally sinks. A combination of pleiotropic and epistasis effects, as well as secondary mutations, may explain variations in WS phenotype and fitness. Understanding how mutations subvert regulatory networks to express intrinsic genome potential and key innovations providing a selective advantage in novel environments is key to understanding the versatility of bacteria, and how selection and ecological opportunity can rapidly lead to substantive changes in phenotype and in community structure and function.}, } @article {pmid28534905, year = {2017}, author = {Basak, A and Abouelhassan, Y and Zuo, R and Yousaf, H and Ding, Y and Huigens, RW}, title = {Antimicrobial peptide-inspired NH125 analogues: bacterial and fungal biofilm-eradicating agents and rapid killers of MRSA persisters.}, journal = {Organic & biomolecular chemistry}, volume = {15}, number = {26}, pages = {5503-5512}, doi = {10.1039/c7ob01028a}, pmid = {28534905}, issn = {1477-0539}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis/chemistry/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Fungi/drug effects ; Humans ; Imidazoles/chemical synthesis/chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {During microbial infection, antimicrobial peptides are utilized by the immune response to rapidly eradicate microbial pathogens through the destruction of cellular membranes. Inspired by antimicrobial peptides, quaternary ammonium cationic (QAC) compounds have emerged as agents capable of destroying bacterial membranes leading to rapid bacterial death, including the eradication of persistent, surface-attached bacterial biofilms. NH125, an imidazolium cation with a sixteen membered fatty tail, was recently reported to eradicate persister cells and was our starting point for the development of novel antimicrobial agents. Here, we describe the design, chemical synthesis and biological investigations of a collection of 30 diverse NH125 analogues which provided critical insights into structural features that are important for antimicrobial activities in this class. From these studies, multiple NH125 analogues were identified to possess potent antibacterial and antifungal activities, eradicate both bacterial and fungal biofilms and rapidly eradicate MRSA persister cells in stationary phase. NH125 analogues also demonstrated more rapid persister cell killing activities against MRSA when tested alongside a panel of diverse membrane-active agents, including BAC-16 and daptomycin. NH125 analogues could have a significant impact on persister- and biofilm-related problems in numerous biomedical applications.}, } @article {pmid28534862, year = {2017}, author = {Nielsen, SM and Meyer, RL and Nørskov-Lauritsen, N}, title = {Differences in Gene Expression Profiles between Early and Late Isolates in Monospecies Achromobacter Biofilm.}, journal = {Pathogens (Basel, Switzerland)}, volume = {6}, number = {2}, pages = {}, pmid = {28534862}, issn = {2076-0817}, abstract = {Bacteria of genus Achromobacter are emerging pathogens in cystic fibrosis (CF) capable of biofilm formation and development of antimicrobial resistance. Evolutionary adaptions in the transition from primary to chronic infection were assessed by transcriptomic analysis of successive isolates of Achromobacter xylosoxidans from a single CF patient. Several efflux pump systems targeting antimicrobial agents were upregulated during the course of the disease, whereas all genes related to motility were downregulated. Genes annotated to subsystems of sulfur metabolism, protein metabolism and potassium metabolism exhibited the strongest upregulation. K+ channel genes were hyperexpressed, and a putative sulfite oxidase was more than 1500 times upregulated. The transcriptome patterns indicated a pivotal role of sulfur metabolism and electrical signalling in Achromobacter biofilms during late stage CF lung disease.}, } @article {pmid28533383, year = {2017}, author = {Rodesney, CA and Roman, B and Dhamani, N and Cooley, BJ and Katira, P and Touhami, A and Gordon, VD}, title = {Mechanosensing of shear by Pseudomonas aeruginosa leads to increased levels of the cyclic-di-GMP signal initiating biofilm development.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {23}, pages = {5906-5911}, pmid = {28533383}, issn = {1091-6490}, mesh = {Bacterial Adhesion/physiology ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; *Mechanotransduction, Cellular ; Pseudomonas aeruginosa/*physiology ; Stress, Physiological ; }, abstract = {Biofilms are communities of sessile microbes that are phenotypically distinct from their genetically identical, free-swimming counterparts. Biofilms initiate when bacteria attach to a solid surface. Attachment triggers intracellular signaling to change gene expression from the planktonic to the biofilm phenotype. For Pseudomonas aeruginosa, it has long been known that intracellular levels of the signal cyclic-di-GMP increase upon surface adhesion and that this is required to begin biofilm development. However, what cue is sensed to notify bacteria that they are attached to the surface has not been known. Here, we show that mechanical shear acts as a cue for surface adhesion and activates cyclic-di-GMP signaling. The magnitude of the shear force, and thereby the corresponding activation of cyclic-di-GMP signaling, can be adjusted both by varying the strength of the adhesion that binds bacteria to the surface and by varying the rate of fluid flow over surface-bound bacteria. We show that the envelope protein PilY1 and functional type IV pili are required mechanosensory elements. An analytic model that accounts for the feedback between mechanosensors, cyclic-di-GMP signaling, and production of adhesive polysaccharides describes our data well.}, } @article {pmid28533218, year = {2017}, author = {Prüß, BM}, title = {Involvement of Two-Component Signaling on Bacterial Motility and Biofilm Development.}, journal = {Journal of bacteriology}, volume = {199}, number = {18}, pages = {}, pmid = {28533218}, issn = {1098-5530}, mesh = {Biofilms/*growth & development ; Escherichia coli K12/*physiology ; *Gene Expression Regulation, Bacterial ; *Locomotion ; *Signal Transduction ; }, abstract = {Two-component signaling is a specialized mechanism that bacteria use to respond to changes in their environment. Nonpathogenic strains of Escherichia coli K-12 harbor 30 histidine kinases and 32 response regulators, which form a network of regulation that integrates many other global regulators that do not follow the two-component signaling mechanism, as well as signals from central metabolism. The output of this network is a multitude of phenotypic changes in response to changes in the environment. Among these phenotypic changes, many two-component systems control motility and/or the formation of biofilm, sessile communities of bacteria that form on surfaces. Motility is the first reversible attachment phase of biofilm development, followed by a so-called swim or stick switch toward surface organelles that aid in the subsequent phases. In the mature biofilm, motility heterogeneity is generated by a combination of evolutionary and gene regulatory events.}, } @article {pmid28532812, year = {2017}, author = {Jørgensen, E and Bay, L and Bjarnsholt, T and Bundgaard, L and Sørensen, MA and Jacobsen, S}, title = {The occurrence of biofilm in an equine experimental wound model of healing by secondary intention.}, journal = {Veterinary microbiology}, volume = {204}, number = {}, pages = {90-95}, doi = {10.1016/j.vetmic.2017.03.011}, pmid = {28532812}, issn = {1873-2542}, mesh = {Animals ; Bacteria/*isolation & purification ; Bandages/*veterinary ; Biofilms/*growth & development ; Horses/*injuries ; Male ; Wound Healing/*physiology ; }, abstract = {In humans, biofilm is a well-known cause of delayed healing and low-grade inflammation of chronic wounds. In horses, biofilm formation in wounds has been studied to a very limited degree. The objective of this study was thus to investigate the occurrence of biofilm in equine experimental wounds healing by secondary intention. Tissue biopsies from non-contaminated, experimental excisional shoulder and limb wounds were obtained on day 1-2, day 7-10 and day 14-15 post-wounding. Limb wounds were either un-bandaged or bandaged to induce exuberant granulation tissue (EGT) formation and thereby impaired healing. Presence of biofilm in tissue biopsies was assessed by peptide nucleic acid fluorescence in situ hybridization (PNA FISH) and confocal laser scanning microscopy (CLSM). Bandaged limb wounds developed EGT and displayed delayed healing, while shoulder and un-bandaged limb wounds healed normally. Biofilm was detected in limb wounds only. At day 14-15 biofilm was significantly more prevalent in bandaged limb wounds than in un-bandaged limb wounds (P=0.003). Further, bandaged limb wounds had a statistically significant increase in biofilm burden from day 7-10 to day 14-15 (P=0.009). The finding that biofilm was most prevalent in bandaged limb wounds with EGT formation suggests that biofilm may be linked to delayed wound healing in horses, as has been observed in humans. The inability to clear bacteria could be related to hypoxia and low-grade inflammation in the EGT, but the interaction between biofilm forming bacteria and wound healing in horses needs further elucidation.}, } @article {pmid28532058, year = {2017}, author = {Kulkarni, M and Junkar, I and Humpolíček, P and Capáková, Z and Radaszkiewicz, KA and Mikušová, N and Pacherník, J and Lehocký, M and Iglič, A and Hanáčková, M and Mozetič, M}, title = {Interaction of nanostructured TiO2 biointerfaces with stem cells and biofilm-forming bacteria.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {77}, number = {}, pages = {500-507}, doi = {10.1016/j.msec.2017.03.174}, pmid = {28532058}, issn = {1873-0191}, mesh = {Bacteria ; Biofilms ; Humans ; *Nanostructures ; Nanotubes ; Stem Cells ; Titanium ; }, abstract = {Nanostructured TiO2 nanotubes (NTs) of diameters from 15 to 100nm were fabricated by an electrochemical anodization process. Biofilm-positive strains of Bacillus cereus and Pseudomonas aeruginosa behaved similarly on all TiO2 NTs as well as on native titanium (Ti) foil. The adhesion and growth of mesenchymal stem cells (MSc), embryonic stem cells (ESc), and pure cardiomyocytes derived from ESc exhibited significant differences. MSc as well as ESc were, in contrast to cardiomyocytes, able to adhere, and grow on TiO2 NTs. A correlation between NTs diameter and cell behaviour was however observed in the case of MSc and ESc. MSc were not in a physiological state in the case of 100nm TiO2 NTs, while ESc were not able to grow on 15nm TiO2 NTs. It can be stated that these differences can be assigned to different diameters of the NTs but not to the chemistry of the surface. This is the first study describing the comprehensive behaviour of both eukaryotic and prokaryotic cells on TiO2 NTs. On the basis of obtained results, it can be concluded that new generation of medical devices providing selective cell behaviour can be fabricated by optimizing the nanoscale morphology of TiO2.}, } @article {pmid28532022, year = {2017}, author = {Liu, T and Dan, W and Dan, N and Liu, X and Liu, X and Peng, X}, title = {A novel grapheme oxide-modified collagen-chitosan bio-film for controlled growth factor release in wound healing applications.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {77}, number = {}, pages = {202-211}, doi = {10.1016/j.msec.2017.03.256}, pmid = {28532022}, issn = {1873-0191}, mesh = {Animals ; Chitosan ; Collagen ; Oxides ; Rats ; Rats, Sprague-Dawley ; *Wound Healing ; }, abstract = {Collagen-chitosan composite film modified with grapheme oxide (GO) and 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), termed CC-G-E film, was loaded with basic fibroblast growth factor (bFGF) as the development of an efficacious wound healing device. In this study we report a novel drug delivery system that prevents the initial burst release and loss of bioactivity of drugs in vitro and in vivo applications. The results showed that CC-G-E film possessed improved thermal stability and a higher rate of crosslinking with increased mechanical properties when the dosage of GO was between 0.03% and 0.07%. It was shown that the in vitro release of bFGF from CC-G-E film continued for more than 28d. Furthermore, the CC-G-E films demonstrated excellent in vitro biocompatibility following culture with L929 fibroblasts in terms of cell adhesion and proliferation. CC-G-E films were implanted into Sprague-Dawley rats to characterize their ability to repair full-thickness skin wounds. Results showed that the CC-G-E film accelerated the wound healing process compared with the blank control. Based on all the results, it was concluded that CC-G-E film operates as a novel drug delivery system and due to its performance in wound remodeling, has potential to be developed as a wound dressing material.}, } @article {pmid28530651, year = {2017}, author = {Kim, MK and Zhao, A and Wang, A and Brown, ZZ and Muir, TW and Stone, HA and Bassler, BL}, title = {Surface-attached molecules control Staphylococcus aureus quorum sensing and biofilm development.}, journal = {Nature microbiology}, volume = {2}, number = {}, pages = {17080}, pmid = {28530651}, issn = {2058-5276}, support = {/HHMI/Howard Hughes Medical Institute/United States ; R01 AI042783/AI/NIAID NIH HHS/United States ; R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*drug effects/*growth & development ; Environmental Microbiology ; *Quorum Sensing ; *Second Messenger Systems ; Staphylococcus aureus/*drug effects/*physiology ; *Surface Properties ; }, abstract = {Bacteria use a process called quorum sensing to communicate and orchestrate collective behaviours, including virulence factor secretion and biofilm formation. Quorum sensing relies on the production, release, accumulation and population-wide detection of signal molecules called autoinducers. Here, we develop concepts to coat surfaces with quorum-sensing-manipulation molecules as a method to control collective behaviours. We probe this strategy using Staphylococcus aureus. Pro- and anti-quorum-sensing molecules can be covalently attached to surfaces using click chemistry, where they retain their abilities to influence bacterial behaviours. We investigate key features of the compounds, linkers and surfaces necessary to appropriately position molecules to interact with cognate receptors and the ability of modified surfaces to resist long-term storage, repeated infections, host plasma components and flow-generated stresses. Our studies highlight how this surface approach can be used to make colonization-resistant materials against S. aureus and other pathogens and how the approach can be adapted to promote beneficial behaviours of bacteria on surfaces.}, } @article {pmid28530167, year = {2017}, author = {Woodcock, S and Sloan, WT}, title = {Biofilm community succession: a neutral perspective.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {5}, pages = {664-668}, doi = {10.1099/mic.0.000472}, pmid = {28530167}, issn = {1465-2080}, abstract = {Although biofilms represent one of the dominant forms of life in aqueous environments, our understanding of the assembly and development of their microbial communities remains relatively poor. In recent years, several studies have addressed this and have extended the concepts of succession theory in classical ecology into microbial systems. From these datasets, niche-based conceptual models have been developed explaining observed biodiversity patterns and their dynamics. These models have not, however, been formulated mathematically and so remain untested. Here, we further develop spatially resolved neutral community models and demonstrate that these can also explain these patterns and offer alternative explanations of microbial succession. The success of neutral models suggests that stochastic effects alone may have a much greater influence on microbial community succession than previously acknowledged. Furthermore, such models are much more readily parameterised and can be used as the foundation of more complex and realistic models of microbial community succession.}, } @article {pmid28529089, year = {2017}, author = {Argemi, X and Prévost, G and Riegel, P and Provot, C and Badel-Berchoux, S and Jehl, F and Olivares, E and Hansmann, Y}, title = {Kinetics of biofilm formation by Staphylococcus lugdunensis strains in bone and joint infections.}, journal = {Diagnostic microbiology and infectious disease}, volume = {88}, number = {4}, pages = {298-304}, doi = {10.1016/j.diagmicrobio.2017.05.002}, pmid = {28529089}, issn = {1879-0070}, mesh = {Aged ; Biofilms/*growth & development ; Bone and Bones/*microbiology ; Female ; Humans ; Joints/*microbiology ; Kinetics ; Male ; Middle Aged ; Staphylococcal Infections/*microbiology ; Staphylococcus lugdunensis/*growth & development ; }, abstract = {OBJECTIVE: To describe the clinical presentation and 1-year follow-up of patients with bone and joint infections (BJIs) caused by Staphylococcus lugdunensis and evaluate its biofilm-forming capacities.

PATIENTS AND METHODS: Overall, 28 patients with BJIs from VISLISI clinical trials were included. We evaluated 1-year clinical follow-up and analyzed biofilm production kinetics of the 28 strains using the BioFilm Ring Test®.

RESULTS: Of all patients, 12 had osteoarticular infections without material and 16 had prosthetic joint infections, of which 9 underwent a 1-stage revision procedure. At the 1-year follow-up, all patients were cured but needed a surgical intervention. Diabetes affected 46.4% of all patients. Of all, 20 strains (71.4%) started biofilm formation within 2 h, but all strains started the formation after 4 h experiment, and 25 strains (89.3%) reached a maximum after 6 h.

CONCLUSIONS: This study describes the clinical and surgical management of BJIs caused by S. lugdunensis and shows that 1-stage prosthesis exchange procedures may be efficient. Further, It shows that biofilm production by this strain was not marginal and directly impacted clinical and surgical management.}, } @article {pmid28526864, year = {2017}, author = {Meir, O and Zaknoon, F and Cogan, U and Mor, A}, title = {A broad-spectrum bactericidal lipopeptide with anti-biofilm properties.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {2198}, pmid = {28526864}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Lipopeptides/chemistry/*pharmacology ; Molecular Structure ; Streptococcus mutans/drug effects ; }, abstract = {Previous studies of the oligoacyllysyl (OAK) series acyl-lysyl-lysyl-aminoacyl-lysine-amide, suggested their utility towards generating robust linear lipopeptide-like alternatives to antibiotics, although to date, none exhibited potent broad-spectrum bactericidal activity. To follow up on this premise, we produced a new analog (C14KKc12K) and investigated its properties in various media. Mechanistic studies suggest that C14KKc12K uses a non-specific membrane-disruptive mode of action for rapidly reducing viability of Gram-negative bacteria (GNB) similarly to polymyxin B (PMB), a cyclic lipopeptide used as last resort antibiotic. Indeed, C14KKc12K displayed similar affinity for lipopolysaccharides and induced cell permeabilization associated with rapid massive membrane depolarization. Unlike PMB however, C14KKc12K was also bactericidal to Gram-positive bacteria (GPB) at or near the minimal inhibitory concentration (MIC), as assessed against a multispecies panel of >50 strains, displaying MIC50 at 3 and 6 µM, respectively for GPB and GNB. C14KKc12K retained activity in human saliva, reducing the viability of cultivable oral microflora by >99% within two minutes of exposure, albeit at higher concentrations, which, nonetheless, were similar to the commercial gold standard, chlorhexidine. This equipotent bactericidal activity was also observed in pre-formed biofilms of Streptococcus mutans, a major periodontal pathogen. Such compounds therefore, may be useful for eradication of challenging poly-microbial infections.}, } @article {pmid28526794, year = {2017}, author = {Nagasawa, R and Sato, T and Senpuku, H}, title = {Raffinose Induces Biofilm Formation by Streptococcus mutans in Low Concentrations of Sucrose by Increasing Production of Extracellular DNA and Fructan.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {15}, pages = {}, pmid = {28526794}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; DNA, Bacterial/genetics/*metabolism ; Extracellular Space/genetics/*metabolism ; Fructans/*metabolism ; Raffinose/*metabolism ; Streptococcus mutans/genetics/*physiology ; Sucrose/analysis/*metabolism ; }, abstract = {Streptococcus mutans is the primary etiological agent of dental caries and causes tooth decay by forming a firmly attached biofilm on tooth surfaces. Biofilm formation is induced by the presence of sucrose, which is a substrate for the synthesis of extracellular polysaccharides but not in the presence of oligosaccharides. Nonetheless, in this study, we found that raffinose, which is an oligosaccharide with an intestinal regulatory function and antiallergic effect, induced biofilm formation by S. mutans in a mixed culture with sucrose, which was at concentrations less than those required to induce biofilm formation directly. We analyzed the possible mechanism behind the small requirement for sucrose for biofilm formation in the presence of raffinose. Our results suggested that sucrose contributed to an increase in bacterial cell surface hydrophobicity and biofilm formation. Next, we examined how the effects of raffinose interacted with the effects of sucrose for biofilm formation. We showed that the presence of raffinose induced fructan synthesis by fructosyltransferase and aggregated extracellular DNA (eDNA, which is probably genomic DNA released from dead cells) into the biofilm. eDNA seemed to be important for biofilm formation, because the degradation of DNA by DNase I resulted in a significant reduction in biofilm formation. When assessing the role of fructan in biofilm formation, we found that fructan enhanced eDNA-dependent cell aggregation. Therefore, our results show that raffinose and sucrose have cooperative effects and that this induction of biofilm formation depends on supportive elements that mainly consist of eDNA and fructan.IMPORTANCE The sucrose-dependent mechanism of biofilm formation in Streptococcus mutans has been studied extensively. Nonetheless, the effects of carbohydrates other than sucrose are inadequately understood. Our findings concerning raffinose advance the understanding of the mechanism underlying the joint effects of sucrose and other carbohydrates on biofilm formation. Since raffinose has been reported to have positive effects on enterobacterial flora, research on the effects of raffinose on the oral flora are required prior to its use as a beneficial sugar for human health. Here, we showed that raffinose induced biofilm formation by S. mutans in low concentrations of sucrose. The induction of biofilm formation generally generates negative effects on the oral flora. Therefore, we believe that this finding will aid in the development of more effective oral care techniques to maintain oral flora health.}, } @article {pmid28525841, year = {2017}, author = {Kim, EY and Rajasekaran, G and Shin, SY}, title = {LL-37-derived short antimicrobial peptide KR-12-a5 and its d-amino acid substituted analogs with cell selectivity, anti-biofilm activity, synergistic effect with conventional antibiotics, and anti-inflammatory activity.}, journal = {European journal of medicinal chemistry}, volume = {136}, number = {}, pages = {428-441}, doi = {10.1016/j.ejmech.2017.05.028}, pmid = {28525841}, issn = {1768-3254}, mesh = {Amino Acids/chemistry/*pharmacology ; Animals ; Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Mice ; Microbial Sensitivity Tests ; Molecular Structure ; NIH 3T3 Cells ; RAW 264.7 Cells ; Structure-Activity Relationship ; Cathelicidins ; }, abstract = {KR-12-a5 is a 12-meric α-helical antimicrobial peptide (AMP) with dual antimicrobial and anti-inflammatory activities designed from human cathelicidin LL-37. We designed and synthesized a series of d-amino acid-substituted analogs of KR-12-a5 with the aim of developing novel α-helical AMPs that possess higher cell selectivity than KR-12-a5, while maintaining the anti-inflammatory activity. d-amino acid incorporation into KR-12-a5 induced a significant improvement in the cell selectivity by 2.6- to 13.6-fold as compared to KR-12-a5, while maintaining the anti-inflammatory activity. Among the three analogs, KR-12-a5 (6-[D]L) with d-amino acid in the polar-nonpolar interface (Leu[6]) showed the highest cell selectivity (therapeutic index: 61.2). Similar to LL-37, KR-12-a5 and its analogs significantly inhibited the expression and secretion of NO, TNF-α, IL-6 and MCP-1 from LPS-stimulated RAW264.7 cells. KR-12-a5 and its analogs showed a more potent antimicrobial activity against antibiotic-resistant bacteria, including clinically isolated MRSA, MDRPA, and VREF than LL-37 and melittin. Furthermore, compared to LL-37, KR-12-a5 and its analogs showed greater synergistic effects with conventional antibiotics, such as chloramphenicol, ciprofloxacin, and oxacillin against MDRPA; KR-12-a5 and its analogs had a FICI range between 0.25 and 0.5, and LL-37 had a range between 0.75 and 1.5. KR-12-a5 and its analogs were found to be more effective anti-biofilm agents against MDRPA than LL-37. In addition, KR-12-a5 and its analogs maintained antimicrobial activity in physiological salts and human serum. SYTOX Green uptake and membrane depolarization studies revealed that KR-12-a5 and its analogs kills microbial cells by permeabilizing the cell membrane and damaging membrane integrity. Taken together, our results suggest that KR-12-a5 and its analogs can be developed further as novel antimicrobial/anti-inflammatory agents to treat antibiotic-resistant infections.}, } @article {pmid28521511, year = {2017}, author = {Nostro, A and Marino, A and Ginestra, G and Cellini, L and Di Giulio, M and Bisignano, G}, title = {Effects of adaptation to carvacrol on Staphylococcus aureus in the planktonic and biofilm phases.}, journal = {Biofouling}, volume = {33}, number = {6}, pages = {470-480}, doi = {10.1080/08927014.2017.1323080}, pmid = {28521511}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cross Protection ; Cymenes ; Drug Resistance, Bacterial/*drug effects/genetics ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Mutation ; Plankton/*drug effects/growth & development ; Species Specificity ; Staphylococcus aureus/*drug effects/genetics/growth & development ; }, abstract = {The effect of exposure to sub-minimum inhibitory concentrations of carvacrol, for either 3-10 days, on direct (carvacrol) or cross-protection (cinnamaldehyde, eugenol, antibiotics) and the influence on planktonic and biofilm growth of four Staphylococcus aureus strains were reported. The sequential exposure to carvacrol resulted in a direct protection that was more evident in two of the four strains after 10 days. No significant cross-protection against cinnamaldehyde, eugenol and antibiotics was detected. An adaptive response was associated with a prolonged lag phase, a lower yield of bacteria, a colony phenotype likely to be associated to small colony variants and an increase in biofilm production. Generally, the biofilm of the adapted strains was less susceptible to subMICs of carvacrol compared to the biofilms of non-adapted strains. In contrast, it was demonstrated that in the case of mature biofilms the susceptibility was similar. The exposure of S. aureus to carvacrol at concentrations above the MIC resulted in a very low mutation frequency.}, } @article {pmid28516088, year = {2017}, author = {Pierce, CG and Vila, T and Romo, JA and Montelongo-Jauregui, D and Wall, G and Ramasubramanian, A and Lopez-Ribot, JL}, title = {The Candida albicans Biofilm Matrix: Composition, Structure and Function.}, journal = {Journal of fungi (Basel, Switzerland)}, volume = {3}, number = {1}, pages = {}, pmid = {28516088}, issn = {2309-608X}, support = {R01 AI119554/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; R25 GM060655/GM/NIGMS NIH HHS/United States ; }, abstract = {A majority of infections caused by Candida albicans-the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.}, } @article {pmid28515715, year = {2017}, author = {Zhou, J and Bi, S and Chen, H and Chen, T and Yang, R and Li, M and Fu, Y and Jia, AQ}, title = {Anti-Biofilm and Antivirulence Activities of Metabolites from Plectosphaerella cucumerina against Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {769}, pmid = {28515715}, issn = {1664-302X}, abstract = {This study reported the efficacy of the metabolites of Plectosphaerella cucumerina, one phyllosphere fungus from Orychophragmus violaceus, against Pseudomonas aeruginosa quorum sensing (QS) and QS-regulated biofilms. The minimum inhibitory concentration (MIC) of the ethyl acetate (EtOAc) extract from P. cucumerina against P. aeruginosa PAO1 was 1.25 mg mL[-1]. At sub-MIC concentrations, P. cucumerina extract (0.25-1 mg mL[-1]) not only inhibited biofilm formation but also disrupted preformed biofilms of P. aeruginosa PAO1 without affecting its growth. Fluorescence and scanning electron microscope (SEM) showed architectural disruption of the biofilms when treated with P. cucumerina metabolites. Further investigation demonstrated that metabolites in P. cucumerina attenuated the QS-dependent virulence factors. LC-MS/MS spectra coupled with experimentally standard samples suggested that patulin and emodin might act as the principal components possessing anti-biofilm and antivirulence activities. This is the first report of (1) the isolation of P. cucumerina from the phyllosphere of O. violaceus and (2) anti-biofilm, antivirulence, and biofilm disruption activities of this fungus. Thus, this study provides fascinating new pathways for screening antipathogenic agents.}, } @article {pmid28515440, year = {2017}, author = {Yang, H and Abouelhassan, Y and Burch, GM and Kallifidas, D and Huang, G and Yousaf, H and Jin, S and Luesch, H and Huigens, RW}, title = {A Highly Potent Class of Halogenated Phenazine Antibacterial and Biofilm-Eradicating Agents Accessed Through a Modular Wohl-Aue Synthesis.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {2003}, pmid = {28515440}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Cell Survival ; *Chemistry Techniques, Synthetic ; Halogenation ; HeLa Cells ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Phenazines/*chemical synthesis/chemistry/*pharmacology ; Spectrophotometry, Ultraviolet ; Structure-Activity Relationship ; }, abstract = {Unlike individual, free-floating planktonic bacteria, biofilms are surface-attached communities of slow- or non-replicating bacteria encased within a protective extracellular polymeric matrix enabling persistent bacterial populations to tolerate high concentrations of antimicrobials. Our current antibacterial arsenal is composed of growth-inhibiting agents that target rapidly-dividing planktonic bacteria but not metabolically dormant biofilm cells. We report the first modular synthesis of a library of 20 halogenated phenazines (HP), utilizing the Wohl-Aue reaction, that targets both planktonic and biofilm cells. New HPs, including 6-substituted analogues, demonstrate potent antibacterial activities against MRSA, MRSE and VRE (MIC = 0.003-0.78 µM). HPs bind metal(II) cations and demonstrate interesting activity profiles when co-treated in a panel of metal(II) cations in MIC assays. HP 1 inhibited RNA and protein biosynthesis while not inhibiting DNA biosynthesis using [3]H-radiolabeled precursors in macromolecular synthesis inhibition assays against MRSA. New HPs reported here demonstrate potent eradication activities (MBEC = 0.59-9.38 µM) against MRSA, MRSE and VRE biofilms while showing minimal red blood cell lysis or cytotoxicity against HeLa cells. PEG-carbonate HPs 24 and 25 were found to have potent antibacterial activities with significantly improved water solubility. HP small molecules could have a dramatic impact on persistent, biofilm-associated bacterial infection treatments.}, } @article {pmid28514430, year = {2017}, author = {Papenfort, K and Silpe, JE and Schramma, KR and Cong, JP and Seyedsayamdost, MR and Bassler, BL}, title = {Erratum: A Vibrio cholerae autoinducer-receptor pair that controls biofilm formation.}, journal = {Nature chemical biology}, volume = {13}, number = {6}, pages = {691}, pmid = {28514430}, issn = {1552-4469}, } @article {pmid28513784, year = {2017}, author = {Santos, GOD and Milanesi, FC and Greggianin, BF and Fernandes, MI and Oppermann, RV and Weidlich, P}, title = {Chlorhexidine with or without alcohol against biofilm formation: efficacy, adverse events and taste preference.}, journal = {Brazilian oral research}, volume = {31}, number = {}, pages = {e32}, doi = {10.1590/1807-3107BOR-2017.vol31.0032}, pmid = {28513784}, issn = {1807-3107}, mesh = {Adolescent ; Adult ; Anti-Infective Agents, Local/chemistry/pharmacology ; Biofilms/*drug effects ; Chlorhexidine/*chemistry/*pharmacology ; Cross-Over Studies ; Dental Plaque/prevention & control ; Dental Plaque Index ; Double-Blind Method ; Drug Combinations ; Ethanol/*chemistry/*pharmacology ; Female ; Gingiva/drug effects/microbiology ; Humans ; Male ; Mouthwashes/*chemistry/*pharmacology ; Taste ; Time Factors ; Treatment Outcome ; Young Adult ; }, abstract = {In recent years, different chlorhexidine formulations have been tested, including an alcohol-free alternative, but the effect of this solution on early biofilm formation is not clear. A crossover, randomized, double-blind clinical trial was conducted to evaluate the effect of two chlorhexidine solutions against supra- and subgingival biofilm formation (NCT#02656251). Thirty-five participants were randomized and asked to rinse twice daily with 15 ml of an alcohol-containing 0.12% chlorhexidine solution, an alcohol-free 0.12% chlorhexidine solution, or placebo. The study was conducted in three experimental periods of 4 days each, with a 10-day washout between the periods. All the experimental periods followed the same protocol, except that the solutions were switched. Biofilm distribution was evaluated every 24 hours by the Plaque-Free Zone Index, during 96 hours. Adverse events were self-reported and sensory evaluation was performed using a hedonic scale. Compared to the placebo, the chlorhexidine solutions resulted in a significantly higher number of surfaces free of plaque over 96 hours (p < 0.01), and were able to prevent subgingival biofilm formation (p < 0.01). The alcohol-free chlorhexidine solution was associated with a lower incidence of adverse events, compared with alcohol-containing chlorhexidine (p < 0.05); it also received better sensory evaluation and acceptance by trial participants, compared with the alcohol-containing chlorhexidine (p = 0.007), and had a similar inhibitory effect on the formation of supra- and subgingival biofilms.}, } @article {pmid28513576, year = {2017}, author = {Di Domenico, EG and Farulla, I and Prignano, G and Gallo, MT and Vespaziani, M and Cavallo, I and Sperduti, I and Pontone, M and Bordignon, V and Cilli, L and De Santis, A and Di Salvo, F and Pimpinelli, F and Lesnoni La Parola, I and Toma, L and Ensoli, F}, title = {Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype.}, journal = {International journal of molecular sciences}, volume = {18}, number = {5}, pages = {}, pmid = {28513576}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Bacteria/*drug effects/genetics/isolation & purification/pathogenicity ; Bacterial Infections/drug therapy/*microbiology ; Biofilms/*drug effects ; Chronic Disease ; *Drug Resistance, Multiple, Bacterial ; Humans ; Microbial Sensitivity Tests ; Skin Ulcer/drug therapy/*microbiology ; Virulence ; }, abstract = {Bacterial biofilm is a major factor in delayed wound healing and high levels of biofilm production have been repeatedly described in multidrug resistant organisms (MDROs). Nevertheless, a quantitative correlation between biofilm production and the profile of antimicrobial drug resistance in delayed wound healing remains to be determined. Microbial identification, antibiotic susceptibility and biofilm production were assessed in 135 clinical isolates from 87 patients. Gram-negative bacteria were the most represented microorganisms (60.8%) with MDROs accounting for 31.8% of the total isolates. Assessment of biofilm production revealed that 80% of the strains were able to form biofilm. A comparable level of biofilm production was found with both MDRO and not-MDRO with no significant differences between groups. All the methicillin-resistant Staphylococcus aureus (MRSA) and 80% of Pseudomonas aeruginosa MDR strains were found as moderate/high biofilm producers. Conversely, less than 17% of Klebsiella pneumoniae extended-spectrum beta-lactamase (ESBL), Escherichia coli-ESBL and Acinetobacter baumannii were moderate/high biofilm producers. Notably, those strains classified as non-biofilm producers, were always associated with biofilm producer bacteria in polymicrobial colonization. This study shows that biofilm producers were present in all chronic skin ulcers, suggesting that biofilm represents a key virulence determinant in promoting bacterial persistence and chronicity of ulcerative lesions independently from the MDRO phenotype.}, } @article {pmid28512652, year = {2017}, author = {Gänsbauer, M and Burkovski, A and Karl, M and Grobecker-Karl, T}, title = {Comparison of simplistic biofilm models for evaluating irrigating solutions.}, journal = {Quintessence international (Berlin, Germany : 1985)}, volume = {48}, number = {7}, pages = {521-526}, doi = {10.3290/j.qi.a38268}, pmid = {28512652}, issn = {1936-7163}, mesh = {Animals ; Biofilms ; Cattle ; Chlorhexidine/*pharmacology ; Citric Acid/*pharmacology ; Dentin/*drug effects ; Enterococcus faecalis/*drug effects ; Humans ; In Vitro Techniques ; Materials Testing ; Root Canal Irrigants/*pharmacology ; Sodium Hypochlorite/*pharmacology ; }, abstract = {OBJECTIVE: Many innovations have recently been implemented in the field of endodontics, often based on a variety of in-vitro/ex-vivo test setups. It was the goal of this research to compare different biofilm models for evaluating the effectiveness of rinsing solutions.

METHOD AND MATERIALS: Three different models have been applied in this study, including petri dishes with nutrient medium, arrays of human dentin disks, and split bovine root segments. The susceptibility of biofilms formed by Enterococcus faecalis to commonly used endodontic irrigants was tested.

RESULTS: While citric acid 3% did not show an inhibitory effect on solid medium, mean maximum inhibition areolae of 9.8 ± 1.6 mm were found for sodium hypochlorite 3%. Fluorescein solution was shown to penetrate dentin tubules to a depth of 0.5 to 1 mm, indicating that the dentin tubules are not freely accessible, but clotted by E faecalis biofilms. Rinsing root canals with a combination of citric acid, hydrogen peroxide, chlorhexidine, and sodium hypochlorite removed bacterial biofilms from the dentin tubules only to a depth of 0.5 mm, while bacteria in deeper regions were not affected.

CONCLUSION: Standard irrigating solutions inhibit bacterial growth; however, due to the morphology of the tooth, the effect of irrigating media is restricted to the root canal and the adjacent volume of dentin tubules. Results from standardizable diffusion tests seem not to be predictive for clinical performance of irrigating solutions.}, } @article {pmid28511041, year = {2017}, author = {Gagliano, MC and Ismail, SB and Stams, AJM and Plugge, CM and Temmink, H and Van Lier, JB}, title = {Biofilm formation and granule properties in anaerobic digestion at high salinity.}, journal = {Water research}, volume = {121}, number = {}, pages = {61-71}, doi = {10.1016/j.watres.2017.05.016}, pmid = {28511041}, issn = {1879-2448}, mesh = {Anaerobiosis ; *Biofilms ; Bioreactors ; In Situ Hybridization, Fluorescence ; RNA, Ribosomal, 16S ; *Salinity ; Sewage ; *Waste Disposal, Fluid ; }, abstract = {For the anaerobic biological treatment of saline wastewater, Anaerobic Digestion (AD) is currently a possibility, even though elevated salt concentrations can be a major obstacle. Anaerobic consortia and especially methanogenic archaea are very sensitive to fluctuations in salinity. When working with Upflow Sludge Blanket Reactor (UASB) technology, in which the microorganisms are aggregated and retained in the system as a granular biofilm, high sodium concentration negatively affects aggregation and consequently process performances. In this research, we analysed the structure of the biofilm and granules formed during the anaerobic treatment of high salinity (at 10 and 20 g/L of sodium) synthetic wastewater at lab scale. The acclimated inoculum was able to accomplish high rates of organics removal at all the salinity levels tested. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses identified the acetoclastic Methanosaeta harundinacea as the key player involved acetate degradation and microbial attachment/granulation. When additional calcium (1 g/L) was added to overcome the negative effect of sodium on microbial aggregation, during the biofilm formation process microbial attachment and acetate degradation decreased. The same result was observed on granules formation: while calcium had a positive effect on granules strength when added to UASB reactors, Methanosaeta filaments were not present and the degradation of the partially acidified substrate was negatively influenced. This research demonstrated the possibility to get granulation at high salinity, bringing to the forefront the importance of a selection towards Methanosaeta cells growing in filamentous form to obtain strong and healthy granules.}, } @article {pmid28508904, year = {2017}, author = {Wang, L and Miao, Y and Lu, M and Shan, Z and Lu, S and Hou, J and Yang, Q and Liang, X and Zhou, T and Curry, D and Oakes, K and Zhang, X}, title = {Chloride-accelerated Cu-Fenton chemistry for biofilm removal.}, journal = {Chemical communications (Cambridge, England)}, volume = {53}, number = {43}, pages = {5862-5865}, doi = {10.1039/c7cc00928c}, pmid = {28508904}, issn = {1364-548X}, mesh = {*Biofilms ; Chlorides/*chemistry ; Copper/*chemistry ; Hydrogen Peroxide/*chemistry ; Iron/*chemistry ; Nanoparticles/*chemistry ; }, abstract = {Biofilms present challenges to numerous industries. Herein, a simple approach was developed based on chloride-accelerated Fenton chemistry, where copper oxide nanoparticles facilitate efficient generation of reactive chlorine species for biofilm removal.}, } @article {pmid28508523, year = {2017}, author = {Mohmmed, SA and Vianna, ME and Penny, MR and Hilton, ST and Knowles, JC}, title = {The effect of sodium hypochlorite concentration and irrigation needle extension on biofilm removal from a simulated root canal model.}, journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc}, volume = {43}, number = {3}, pages = {102-109}, doi = {10.1111/aej.12203}, pmid = {28508523}, issn = {1747-4477}, mesh = {Biofilms/*drug effects ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*drug effects ; Humans ; Models, Dental ; Printing, Three-Dimensional ; Root Canal Irrigants/*pharmacology ; Root Canal Preparation ; Sodium Hypochlorite/*pharmacology ; Therapeutic Irrigation ; }, abstract = {To investigate the effect of sodium hypochlorite concentration and needle extension on removal of Enterococcus faecalis biofilm, sixty root canal models were 3D printed. Biofilms were grown on the apical 3 mm of the canal for 10 days. Irrigation for 60s with 9 mL of either 5.25% or 2.5% NaOCl or water was performed using a needle inserted either 3 or 2 mm from the canal terminus and imaged using fluorescence microscopy and residual biofilm percentages were calculated using imaging software. The data were analysed using analysis of covariance and two-sample t-tests. A significance level of 0.05 was used throughout. Residual biofilm was less using 5.25% than with 2.5% NaOCl. Statistically significant biofilm removal was evident with the needle placed closer to the canal terminus. A greater reduction of available chlorine and pH was noted as the concentration increased. One-minute irrigation was not sufficient for complete biofilm removal.}, } @article {pmid28507110, year = {2017}, author = {Klein, K and Grønnemose, RB and Alm, M and Brinch, KS and Kolmos, HJ and Andersen, TE}, title = {Controlled Release of Plectasin NZ2114 from a Hybrid Silicone-Hydrogel Material for Inhibition of Staphylococcus aureus Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {7}, pages = {}, pmid = {28507110}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/microbiology ; Delayed-Action Preparations ; Hydrogel, Polyethylene Glycol Dimethacrylate/*chemistry ; Microbial Sensitivity Tests ; Peptides/chemistry ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus is a major human pathogen in catheter-related infections. Modifying catheter material with interpenetrating polymer networks is a novel material technology that allows for impregnation with drugs and subsequent controlled release. Here, we evaluated the potential for combining this system with plectasin derivate NZ2114 in an attempt to design an S. aureus biofilm-resistant catheter. The material demonstrated promising antibiofilm properties, including properties against methicillin-resistant S. aureus, thus suggesting a novel application of this antimicrobial peptide.}, } @article {pmid28507069, year = {2017}, author = {Mashruwala, AA and Gries, CM and Scherr, TD and Kielian, T and Boyd, JM}, title = {SaeRS Is Responsive to Cellular Respiratory Status and Regulates Fermentative Biofilm Formation in Staphylococcus aureus.}, journal = {Infection and immunity}, volume = {85}, number = {8}, pages = {}, pmid = {28507069}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 AI139100/AI/NIAID NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/metabolism ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Fermentation ; Gene Expression Regulation, Bacterial ; N-Acetylmuramoyl-L-alanine Amidase/genetics/*metabolism ; Oxygen/*metabolism ; Phenotype ; Phosphorylation ; Protein Kinases/*metabolism ; Staphylococcus aureus/genetics/metabolism/*physiology ; Teichoic Acids/metabolism ; Transcription Factors ; }, abstract = {Biofilms are multicellular communities of microorganisms living as a quorum rather than as individual cells. The bacterial human pathogen Staphylococcus aureus uses oxygen as a terminal electron acceptor during respiration. Infected human tissues are hypoxic or anoxic. We recently reported that impaired respiration elicits a programmed cell lysis (PCL) phenomenon in S. aureus leading to the release of cellular polymers that are utilized to form biofilms. PCL is dependent upon the AtlA murein hydrolase and is regulated, in part, by the SrrAB two-component regulatory system (TCRS). In the current study, we report that the SaeRS TCRS also governs fermentative biofilm formation by positively influencing AtlA activity. The SaeRS-modulated factor fibronectin-binding protein A (FnBPA) also contributed to the fermentative biofilm formation phenotype. SaeRS-dependent biofilm formation occurred in response to changes in cellular respiratory status. Genetic evidence presented suggests that a high cellular titer of phosphorylated SaeR is required for biofilm formation. Epistasis analyses found that SaeRS and SrrAB influence biofilm formation independently of one another. Analyses using a mouse model of orthopedic implant-associated biofilm formation found that both SaeRS and SrrAB govern host colonization. Of these two TCRSs, SrrAB was the dominant system driving biofilm formation in vivo We propose a model wherein impaired cellular respiration stimulates SaeRS via an as yet undefined signal molecule(s), resulting in increasing expression of AtlA and FnBPA and biofilm formation.}, } @article {pmid28507063, year = {2017}, author = {Wright, CC and Hsu, FF and Arnett, E and Dunaj, JL and Davidson, PM and Pacheco, SA and Harriff, MJ and Lewinsohn, DM and Schlesinger, LS and Purdy, GE}, title = {The Mycobacterium tuberculosis MmpL11 Cell Wall Lipid Transporter Is Important for Biofilm Formation, Intracellular Growth, and Nonreplicating Persistence.}, journal = {Infection and immunity}, volume = {85}, number = {8}, pages = {}, pmid = {28507063}, issn = {1098-5522}, support = {R33 HL120760/HL/NHLBI NIH HHS/United States ; R21 HL120760/HL/NHLBI NIH HHS/United States ; P41 GM103422/GM/NIGMS NIH HHS/United States ; P30 DK056341/DK/NIDDK NIH HHS/United States ; R01 AI087840/AI/NIAID NIH HHS/United States ; R21 AI113074/AI/NIAID NIH HHS/United States ; P30 DK020579/DK/NIDDK NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Biological Transport ; Cell Wall/*chemistry/metabolism ; Cytoplasm/*microbiology ; Lipids/physiology ; Membrane Proteins/*metabolism ; Membrane Transport Proteins/genetics/*metabolism ; Mutation ; Mycobacterium tuberculosis/genetics/growth & development/pathogenicity/*physiology ; Virulence Factors ; }, abstract = {The mycobacterial cell wall is crucial to the host-pathogen interface, because it provides a barrier against antibiotics and the host immune response. In addition, cell wall lipids are mycobacterial virulence factors. The mycobacterial membrane protein large (MmpL) proteins are cell wall lipid transporters that are important for basic mycobacterial physiology and Mycobacterium tuberculosis pathogenesis. MmpL3 and MmpL11 are conserved across pathogenic and nonpathogenic mycobacteria, a feature consistent with an important role in the basic physiology of the bacterium. MmpL3 is essential and transports trehalose monomycolate to the mycobacterial surface. In this report, we characterize the role of MmpL11 in M. tuberculosis. M. tuberculosismmpL11 mutants have altered biofilms associated with lower levels of mycolic acid wax ester and long-chain triacylglycerols than those for wild-type bacteria. While the growth rate of the mmpL11 mutant is similar to that of wild-type M. tuberculosis in macrophages, the mutant exhibits impaired survival in an in vitro granuloma model. Finally, we show that the survival or recovery of the mmpL11 mutant is impaired when it is incubated under conditions of nutrient and oxygen starvation. Our results suggest that MmpL11 and its cell wall lipid substrates are important for survival in the context of adaptive immune pressure and for nonreplicating persistence, both of which are critically important aspects of M. tuberculosis pathogenicity.}, } @article {pmid28505288, year = {2017}, author = {González, MJ and Robino, L and Iribarnegaray, V and Zunino, P and Scavone, P}, title = {Effect of different antibiotics on biofilm produced by uropathogenic Escherichia coli isolated from children with urinary tract infection.}, journal = {Pathogens and disease}, volume = {75}, number = {4}, pages = {}, doi = {10.1093/femspd/ftx053}, pmid = {28505288}, issn = {2049-632X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriological Techniques ; Biofilms/*drug effects/growth & development ; Child ; Escherichia coli Infections/*microbiology ; Humans ; Urinary Tract Infections/*microbiology ; Uropathogenic Escherichia coli/*drug effects/isolation & purification/*physiology ; }, abstract = {Recurrent urinary tract infections (UTIs) occur frequently in children and women. Intracellular bacterial communities (IBCs) and biofilm formation by Escherichia coli are risk factors for recurrence. The aim of this study was to evaluate the effect of different antibiotics on biofilms by E. coli strains isolated from children with UTI and to correlate virulence factors and IBCs with biofilm formation. A total of 116 E. coli strains were tested for biofilm formation using the crystal violet microplate technique. 58.6% of the strains did not produce biofilm, while 16.4%, 18.1% and 6.8% formed weak, moderate and strong biofilms, respectively. No correlation was found between the ability to form biofilms and the presence of IBCs. Biofilm formation was significantly associated with pili P codifying genes, whereas other virulence factors were not statistically associated. Antibiotics, including ampicillin, cephalothin, ceftriaxone, ceftazidime, amikacin and ciprofloxacin, were evaluated at different concentrations after 48 h of biofilm formation. Except ampicillin, the other antibiotics tested induced a significant reduction of biofilm biomass. In the case of recurrent UTIs potentially associated with the presence of biofilm, the use of third-generation cephalosporin, fluoroquinolones and aminoglycosides could be recommended. These antibiotics demonstrated to reduce biofilm biomass produced even by resistant strains.}, } @article {pmid28504817, year = {2016}, author = {Silva-Santana, G and Lenzi-Almeida, KC and Lopes, VGS and Aguiar-Alves, F}, title = {Biofilm formation in catheter-related infections by Panton-Valentine leukocidin-producing Staphylococcus aureus.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {19}, number = {4}, pages = {199-207}, doi = {10.2436/20.1501.01.278}, pmid = {28504817}, issn = {1139-6709}, mesh = {Animals ; Bacterial Toxins/*biosynthesis ; Biofilms/*growth & development ; Catheter-Related Infections/*microbiology ; Exotoxins/*biosynthesis ; Humans ; Leukocidins/*biosynthesis ; Male ; Methicillin-Resistant Staphylococcus aureus/growth & development/pathogenicity ; Mice ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*growth & development/pathogenicity ; }, abstract = {The use of invasive techniques, such as intravascular catheter insertion, and the formation of biofilms in several devices by methicillin-resistant Staphylococcus aureus (MRSA) have contributed to the increased number of septic patients, morbidity and mortality. This study aimed to evaluate the virulence of strains through catheter colonization and identification of microbial biofilm, as well as pathological changes on the colonized skin. An experimental biofilm formation model utilized catheter fragments implanted subcutaneously in 25 Swiss mice. The technique consisted of inoculating a catheter fragment on the back of each animal, followed by intradermal inoculation of 50 μl of bacterial suspension at 1.0 × 10[7] colony forming units/ml. After 96 h, catheters were removed for macroscopic analysis and evaluated through culture. Local skin fragments were also extracted for histopathology analysis. Staphylococcus aureus can adhere to catheters, colonize and form biofilms. The high amount of viable bacterial cells colonizing catheters and virulence factors can lead to severe infections of skin and adjacent tissues. [Int Microbiol 19(4): 199-207 (2016)].}, } @article {pmid28504348, year = {2017}, author = {Tan, JPK and Coady, DJ and Sardon, H and Yuen, A and Gao, S and Lim, SW and Liang, ZC and Tan, EW and Venkataraman, S and Engler, AC and Fevre, M and Ono, R and Yang, YY and Hedrick, JL}, title = {Broad Spectrum Macromolecular Antimicrobials with Biofilm Disruption Capability and In Vivo Efficacy.}, journal = {Advanced healthcare materials}, volume = {6}, number = {16}, pages = {}, doi = {10.1002/adhm.201601420}, pmid = {28504348}, issn = {2192-2659}, mesh = {Animals ; *Anti-Infective Agents/chemistry/pharmacology/therapeutic use/toxicity ; Bacteremia/drug therapy ; Biofilms/*drug effects ; Female ; Hemolysis/drug effects ; *Heterocyclic Compounds, 4 or More Rings/chemistry/pharmacology/therapeutic use/toxicity ; Mice ; Mice, Inbred BALB C ; Polymerization ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects ; }, abstract = {In this study, antimicrobial polymers are synthesized by the organocatalytic ring-opening polymerization of an eight-membered heterocyclic carbonate monomer that is subsequently quaternized with methyl iodide. These polymers demonstrate activity against clinically relevant Gram-positive Staphylococcus epidermidis and Staphylococcus aureus, Gram-negative Escherichia coli and Pseudomonas aeruginosa, and fungus Candida albicans with fast killing kinetics. Importantly, the polymer efficiently inhibits biofilm growth and lyses existing biofilm, leading to a reduction in biomass and cell viability. In addition, the macromolecular antimicrobial is less likely to induce resistance as it acts via a membrane-lytic mechanism. The polymer is not cytotoxic toward mammalian cells with LD50 of 99.0 ± 11.6 mg kg[-1] in mice through i.v. injection. In an S. aureus blood stream infection mouse model, the polymer removes bacteria from the blood more rapidly than the antibiotic Augmentin. At the effective dose, the polymer treatment does not damage liver and kidney tissues or functions. In addition, blood electrolyte balance remains unchanged after the treatment. The low cost of starting materials, ease of synthesis, nontoxicity, broad spectrum activity with fast killing kinetics, and in vivo antimicrobial activity make these macromolecular antimicrobials ideal candidates for prevention of sepsis and treatment of infections.}, } @article {pmid28502956, year = {2017}, author = {Jardak, M and Abdelli, F and Laadhar, R and Lami, R and Stien, D and Aifa, S and Mnif, S}, title = {Evaluation of biofilm-forming ability of bacterial strains isolated from the roof of an old house.}, journal = {The Journal of general and applied microbiology}, volume = {63}, number = {3}, pages = {186-194}, doi = {10.2323/jgam.2016.10.005}, pmid = {28502956}, issn = {1349-8037}, mesh = {Bacteria/*isolation & purification/metabolism ; Bacterial Adhesion ; Biodiversity ; Biofilms/*growth & development ; Congo Red/metabolism ; Construction Materials/*microbiology ; Culture Media/chemistry ; Gentian Violet/metabolism ; *Housing ; Microbial Viability ; Oxazines/metabolism ; Staphylococcus epidermidis/*physiology ; Tunisia ; Xanthenes/metabolism ; }, abstract = {The bacterial diversity associated with biofilm-forming ability was studied. Eighteen bacterial strains were isolated from a microbial film collected from the roof of an old house located in Sfax, Tunisia. The purity of these microorganisms was confirmed by microscopic observation after repeated streaking on a Tryptic Soy agar medium. Biofilm formation was estimated using preliminary tests including a motility test, microbial adhesion to solvents (MATS), and the Congo Red Agar method (CRA). Since these tests showed no significant result, microplate tests, such as crystal violet and resazurin assays, were used. The results obtained showed that strain S61 was able to form a biofilm within 24 h (OD570 = 4.87). The viability of the S61 biofilm with resazurin assessed with fluorescence measurement was about 1.5 × 10[3]. The S61 strain was identified as Staphylococcus epidermidis. In the biofilm studied here, it was the most biofilm-forming bacterium and will be used as a bacterial model for studying anti-biofilm activity.}, } @article {pmid28502052, year = {2017}, author = {Chen, W and Gu, Y and Xu, H and Liu, Z and Lu, C and Lin, C}, title = {Variation of microbial communities and functional genes during the biofilm formation in raw water distribution systems and associated effects on the transformation of nitrogen pollutants.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {18}, pages = {15347-15359}, pmid = {28502052}, issn = {1614-7499}, mesh = {Bacteria ; *Biofilms ; Biomass ; *Denitrification ; *Genes, Bacterial ; Nitrification ; *Nitrogen ; Water ; }, abstract = {This study aimed to investigate the variation of microbial communities and functional genes during the biofilm formation in raw water distribution systems without prechlorination and associated effects on the transformation of nitrogen pollutants by using a designed model pipe system. The results showed the transformation of nitrogen pollutants was obvious during the biofilm formation. The richness and diversity of the microbial communities changed significantly. The higher abundance of Nitrospirae in biofilm samples significantly contributed to biological nitrification. In particular, the stable content of Bacteroidetes in the biofilm and soluble microbial products released by the biomass might have enhanced the increase in dissolved organic nitrogen. In addition, the variation tendency of nitrogen functional gene abundances and their strong effects on NH4[+]-N, NO2[-]-N, and NO3[-]-N transformation were clearly observed. These findings provide new insights into the evolution of microbial communities and functional genes during the initial operation period of real-world raw water distribution pipes and highlight management and possible safety issues in the subsequent water treatment process.}, } @article {pmid28500045, year = {2017}, author = {Liu, C and Yang, J and Liu, L and Li, B and Yuan, H and Liu, W}, title = {Sodium Lactate Negatively Regulates Shewanella putrefaciens CN32 Biofilm Formation via a Three-Component Regulatory System (LrbS-LrbA-LrbR).}, journal = {Applied and environmental microbiology}, volume = {83}, number = {14}, pages = {}, pmid = {28500045}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms/drug effects ; *Gene Expression Regulation, Bacterial/drug effects ; Histidine Kinase/genetics/*metabolism ; Phosphoric Diester Hydrolases/genetics/*metabolism ; Shewanella putrefaciens/*drug effects/genetics/*physiology ; Sodium Lactate/*pharmacology ; Transcription Factors/genetics/*metabolism ; }, abstract = {The capability of biofilm formation has a major impact on the industrial and biotechnological applications of Shewanella putrefaciens CN32. However, the detailed regulatory mechanisms underlying biofilm formation in this strain remain largely unknown. In the present report, we describe a three-component regulatory system which negatively regulates the biofilm formation of S. putrefaciens CN32. This system consists of a histidine kinase LrbS (Sputcn32_0303) and two cognate response regulators, including a transcription factor, LrbA (Sputcn32_0304), and a phosphodiesterase, LrbR (Sputcn32_0305). LrbS responds to the signal of the carbon source sodium lactate and subsequently activates LrbA. The activated LrbA then promotes the expression of lrbR, the gene for the other response regulator. The bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) phosphodiesterase LrbR, containing an EAL domain, decreases the concentration of intracellular c-di-GMP, thereby negatively regulating biofilm formation. In summary, the carbon source sodium lactate acts as a signal molecule that regulates biofilm formation via a three-component regulatory system (LrbS-LrbA-LrbR) in S. putrefaciens CN32.IMPORTANCE Biofilm formation is a significant capability used by some bacteria to survive in adverse environments. Numerous environmental factors can affect biofilm formation through different signal transduction pathways. Carbon sources are critical nutrients for bacterial growth, and their concentrations and types significantly influence the biomass and structure of biofilms. However, knowledge about the underlying mechanism of biofilm formation regulation by carbon source is still limited. This work elucidates a modulation pattern of biofilm formation negatively regulated by sodium lactate as a carbon source via a three-component regulatory system in S. putrefaciens CN32, which may serve as a good example for studying how the carbon sources impact biofilm development in other bacteria.}, } @article {pmid28499399, year = {2017}, author = {Teh, AHT and Lee, SM and Dykes, GA}, title = {Identification of potential Campylobacter jejuni genes involved in biofilm formation by EZ-Tn5 Transposome mutagenesis.}, journal = {BMC research notes}, volume = {10}, number = {1}, pages = {182}, pmid = {28499399}, issn = {1756-0500}, mesh = {Bacterial Proteins/genetics ; *Biofilms ; Campylobacter jejuni/classification/*genetics/*physiology ; DNA Transposable Elements/*genetics ; Genes, Bacterial/*genetics ; Mutagenesis, Insertional/*methods ; Mutation ; Species Specificity ; }, abstract = {BACKGROUND: Biofilm formation has been suggested to play a role in the survival of Campylobacter jejuni in the environment and contribute to the high incidence of human campylobacteriosis. Molecular studies of biofilm formation by Campylobacter are sparse.

RESULTS: We attempted to identify genes that may be involved in biofilm formation in seven C. jejuni strains through construction of mutants using the EZ-Tn5 Transposome system. Only 14 mutants with reduced biofilm formation were obtained, all from one strain of C. jejuni. Three different genes of interest, namely CmeB (synthesis of multidrug efflux system transporter proteins), NusG (transcription termination and anti-termination protein) and a putative transmembrane protein (involved in membrane protein function) were identified. The efficiency of the EZ::TN5 transposon mutagenesis approach was strain dependent and was unable to generate any mutants from most of the strains used.

CONCLUSIONS: A diverse range of genes may be involved in biofilm formation by C. jejuni. The application of the EZ::TN5 system for construction of mutants in different Campylobacter strains is limited.}, } @article {pmid28498986, year = {2017}, author = {Velmourougane, K and Prasanna, R and Singh, SB and Kumar, R and Saha, S}, title = {Sequence of inoculation influences the nature of extracellular polymeric substances and biofilm formation in Azotobacter chroococcum and Trichoderma viride.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {7}, pages = {}, doi = {10.1093/femsec/fix066}, pmid = {28498986}, issn = {1574-6941}, mesh = {Azotobacter/*growth & development/*metabolism ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Fungal Polysaccharides/metabolism ; Fungal Proteins/metabolism ; Plankton ; Polymers/*chemistry ; Polysaccharides, Bacterial/metabolism ; Spectroscopy, Fourier Transform Infrared ; Trichoderma/*growth & development/*metabolism ; Uronic Acids/metabolism ; }, abstract = {Extracellular polymeric substances (EPS) are important structural components of biofilms. In the present study, the EPS in biofilms developed using two agriculturally beneficial organisms-Azotobacter chroococcum (Az) and Trichoderma viride (Tv) were quantified and characterised. Time course experiments were undertaken to optimise the EPS yield of biofilm samples resulting from coculture and staggered inoculation. The EPS produced during biofilm formation was found to differ quantitatively and qualitatively in individual cultures (Az alone, Tv alone), and in treatments differing in the sequence of inoculation of bacterium and fungus (Az + Tv coculture, staggered inoculation of Az followed by Tv i.e. Az - Tv, or Tv followed by Az i.e. Tv - Az). Significant enhancement in terms of growth and biofilm formation, as compared to individual inoculation was recorded, with Tv - Az exhibiting higher values of these attributes. The EPS from biofilms showed significantly higher concentrations of protein, acetyl, and uronic acids, while planktonic EPS recorded higher total carbohydrates. Fourier transform infrared spectroscopy analyses illustrated the significant influence on chemical and structural aspects of EPS (planktonic and biofilm). This represents a first report correlating EPS production, cell aggregation and biofilm formation during bacterial-fungal biofilm development, which can have implications in the colonisation of soil and plants.}, } @article {pmid28494247, year = {2017}, author = {Carpenter, CMG and Helbling, DE}, title = {Removal of micropollutants in biofilters: Hydrodynamic effects on biofilm assembly and functioning.}, journal = {Water research}, volume = {120}, number = {}, pages = {211-221}, doi = {10.1016/j.watres.2017.04.071}, pmid = {28494247}, issn = {1879-2448}, mesh = {*Biofilms ; Drinking Water ; Filtration ; Hydrodynamics ; *Water Purification ; }, abstract = {Global water resources contain a variety of micropollutants (MPs), including pharmaceuticals, personal care products, and pesticides. This study investigated the removal of MPs during drinking water production by means of biofiltration. The objective of this work was to investigate the influence of hydrodynamics on biofilm growth and development in a biofiltration process and the consequent effect on MP biotransformation rates. We operated three groups of biofiltration columns continuously for 381 days under three distinct hydrodynamic regimes (superficial velocity: 10, 20, 40 cm h[-1]) and fed them a mixture of 29 micropollutants at low concentrations. Total protein concentrations were used as a surrogate measurement for attached biomass and periodic tracer experiments were conducted to estimate dispersivity and assess changes in the depth of the biological zone in each biofilter. These data revealed significant differences in biofilm assembly among the biofilters; higher superficial velocities led to less concentrated surface biomass but a deeper biological zone and more total biomass. Eleven of the 29 MPs were biotransformed and nine of those could be evaluated to estimate biotransformation rates. The second-order rate constants for all nine MPs were not significantly different among the hydrodynamic regimes. However, a depth-based analysis of biotransformation rates revealed significantly greater second-order rate constants for 5 of the MPs at increasing biofilter depths, suggesting that sparse microbial communities found in deeper and more oligotrophic biofilters had a greater activity for the biotransformation of these MPs. The identification of several transformation products at similar relative distributions suggests that the greater activity was not the result of changing metabolic processes under more oligotrophic conditions. These results improve our fundamental understanding of biofilm assembly and functioning in biofiltration processes.}, } @article {pmid28494209, year = {2017}, author = {Pavlickova, S and Klancnik, A and Dolezalova, M and Mozina, SS and Holko, I}, title = {Antibiotic resistance, virulence factors and biofilm formation ability in Escherichia coli strains isolated from chicken meat and wildlife in the Czech Republic.}, journal = {Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes}, volume = {52}, number = {8}, pages = {570-576}, doi = {10.1080/03601234.2017.1318637}, pmid = {28494209}, issn = {1532-4109}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Chickens/microbiology ; Czech Republic ; Drug Resistance, Bacterial/drug effects ; Escherichia coli/*drug effects/isolation & purification/*pathogenicity/physiology ; Feces/microbiology ; Food Contamination ; Food Microbiology ; Humans ; Meat/*microbiology ; Phylogeny ; Virulence Factors/genetics ; }, abstract = {Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals. Consequently, these commensal bacteria might serve as indicator of antimicrobial usage for human and veterinary purposes in the Czech Republic. Further, 46 out of 66 resistant isolates (70%) were able to form biofilm and we found out statistically significant correlation between prevalence of antibiotic resistance and biofilm formation ability. The highest prevalence of antibiotic resistance was observed in weak biofilm producers. Biofilm formation was not statistically associated with any virulence determinant. However, we confirmed the correlation between prevalence of virulence factors and host origin. Chicken isolates possessed more virulence factors (66%), than isolates from wildlife (37%). We can conclude that the potential spread of antibiotic resistance pattern via the food chain is of high concern for public health. Even more, alarming is that E. coli isolates remain pathogenic potential with ability to form biofilm and these bacteria may persist during food processing and consequently lead to greater risks of food contamination.}, } @article {pmid28493317, year = {2017}, author = {Han, R and Klu, YAK and Chen, J}, title = {Attachment and Biofilm Formation by Selected Strains of Salmonella enterica and Entrohemorrhagic Escherichia coli of Fresh Produce Origin.}, journal = {Journal of food science}, volume = {82}, number = {6}, pages = {1461-1466}, doi = {10.1111/1750-3841.13722}, pmid = {28493317}, issn = {1750-3841}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Enterohemorrhagic Escherichia coli/*physiology ; Fabaceae/*microbiology ; Food Microbiology ; Medicago sativa/*microbiology ; Salmonella enterica/*physiology ; Seedlings/microbiology ; }, abstract = {This study compared the abilities of selected Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) strains of fresh produce origin to form biofilms on polystyrene surface and to attach to alfalfa and bean sprouts. Each of the 7 S. enterica and 4 EHEC inocula (2 mL; 10[7] CFU/mL) was placed in 6 different broths in 24-well polystyrene tissue culture plates at 28 °C for 1 to 7 d. Developed biofilms were quantified using the crystal violet binding assay. In a separate experiment, alfalfa and mung bean sprouts (5 g) were exposed to 25 mL inocula (10[7] CFU/mL) of S. enterica or EHEC at 22 °C for 2 h with shaking at 40 rpm. Contaminated sprouts were thoroughly rinsed and homogenized in 0.1% peptone water, and bacteria attached to sprouts were enumerated. Biofilm mass accumulated on polystyrene surface increased with incubation time (P < 0.05). Among the microbiological media used, LB no salt (NaCl) broth better supported biofilm development (P < 0.05). Two EHEC strains formed more biofilms than the Salmonella and other two EHEC strains (P < 0.05). However, more Salmonella cells (5.66 log CFU/g) attached to sprouts than EHEC cells (3.46 log CFU/g). Both Salmonella and EHEC attached in higher numbers to mung bean, than alfalfa, sprouts (P < 0.05).}, } @article {pmid28493157, year = {2017}, author = {Coleri Cihan, A and Karaca, B and Ozel, BP and Kilic, T}, title = {Determination of the biofilm production capacities and characteristics of members belonging to Bacillaceae family.}, journal = {World journal of microbiology & biotechnology}, volume = {33}, number = {6}, pages = {118}, pmid = {28493157}, issn = {1573-0972}, mesh = {Bacillaceae/*classification/growth & development/isolation & purification/*physiology ; Biofilms/*growth & development ; Culture Media/chemistry ; Hot Temperature ; Osmolar Concentration ; Polystyrenes ; Spores, Bacterial/growth & development/metabolism ; Stainless Steel ; Temperature ; Time Factors ; }, abstract = {The biofilm characteristics of many endospore-forming bacilli, especially the thermophiles are still unclear. In this study, a detailed identification and description of biofilm production characteristics of totally 145 isolates and reference strains belonging to Bacillaceae family, displaying thermophilic (n = 115), facultative thermophilic (n = 24) and mesophilic (n = 6) growth from genera Anoxybacillus, Geobacillus, Thermolongibacillus, Aeribacillus, Brevibacillus, Paenibacillus and Bacillus were presented. The incubation temperatures were adjusted to 37, 45 and 55-65 °C for mesophiles, facultative thermophiles, and thermophiles, respectively. The bacilli were evaluated based on their colony morphotypes on Congo red (CR) agar, their complex exopolysaccharide production on calcofluor supplemented tryptic soy agar, and as well as their pellicle formation at the liquid-air surface in tryptic soy broth cultures. Their biofilm production capabilities were also tested on abiotic surfaces of both polystyrene and stainless steel by crystal violet binding assay and viable biofilm cell enumerations, respectively. As a result, the biofilm production capacities of Bacillaceae members from genera to species level, the effects of osmolarity, temperature, incubation time and abiotic surfaces on biofilm formation as well as the CR morphotypes associated with the biofilm production were able to reveal in a wide group of bacilli. Besides, general enrichment-inoculation approaches and methodologies were also offered, which allow and facilitate the screening and determining the biofilm producing endospore forming bacilli.}, } @article {pmid28491057, year = {2017}, author = {Xu, T and Wu, Y and Lin, Z and Bertram, R and Götz, F and Zhang, Y and Qu, D}, title = {Identification of Genes Controlled by the Essential YycFG Two-Component System Reveals a Role for Biofilm Modulation in Staphylococcus epidermidis.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {724}, pmid = {28491057}, issn = {1664-302X}, abstract = {Biofilms play a crucial role in the pathogenicity of Staphylococcus epidermidis, while little is known about whether the essential YycFG two-component signal transduction system (TCS) is involved in biofilm formation. We used antisense RNA (asRNA) to silence the yycFG TCS in order to study its regulatory functions in S. epidermidis. Strain 1457 expressing asRNA yycF exhibited a significant delay (~4-5 h) in entry to log phase, which was partially complemented by overexpressing ssaA. The expression of asRNA yycF and asRNA yycG resulted in a 68 and 50% decrease in biofilm formation at 6 h, respectively, while they had no significant inhibitory effect on 12 h biofilm formation. The expression of asRNA yycF led to a ~5-fold increase in polysaccharide intercellular adhesion (PIA) production, but it did not affect the expression of accumulation-associated protein (Aap) or the release of extracellular DNA. Consistently, quantitative real-time PCR showed that silencing yycF resulted in an increased transcription of biofilm-related genes, including icaA, arlR, sarA, sarX, and sbp. An in silico search of the YycF regulon for the conserved YycF recognition pattern and a modified motif in S. epidermidis, along with additional gel shift and DNase I footprinting assays, showed that arlR, sarA, sarX, and icaA are directly regulated by YycF. Our data suggests that YycFG modulates S. epidermidis biofilm formation in an ica-dependent manner.}, } @article {pmid28488787, year = {2017}, author = {Kinnunen, M and Gülay, A and Albrechtsen, HJ and Dechesne, A and Smets, BF}, title = {Nitrotoga is selected over Nitrospira in newly assembled biofilm communities from a tap water source community at increased nitrite loading.}, journal = {Environmental microbiology}, volume = {19}, number = {7}, pages = {2785-2793}, doi = {10.1111/1462-2920.13792}, pmid = {28488787}, issn = {1462-2920}, mesh = {Biofilms/*growth & development ; Bioreactors/microbiology ; Drinking Water/microbiology ; Gallionellaceae/classification/growth & development/*metabolism ; Nitrites/*metabolism ; Oxidation-Reduction ; Water Microbiology ; }, abstract = {Community assembly is a central topic in microbial ecology: how do assembly processes interact and what is the relative contribution of stochasticity and determinism? Here, we exposed replicate flow-through biofilm systems, fed with nitrite-supplemented tap water, to continuous immigration from a source community, present in the tap water, to determine the extent of selection and neutral processes in newly assembled biofilm communities at both the community and the functional guild (of nitrite-oxidizing bacteria, NOB) levels. The community composition of biofilms assembled under low and high nitrite loading was described after 40 days of complete nitrite removal. The total community assembly, as well as the NOB guild assembly were largely governed by a combination of deterministic and stochastic processes. Furthermore, we observed deterministic enrichment of certain types of NOB in the biofilms. Specifically, elevated nitrite loading selected for a single Nitrotoga representative, while lower nitrite conditions selected for a number of Nitrospira. Therefore, even when focusing on ecologically coherent ensembles, assembly is the result of complex stochastic and deterministic processes that can only be interrogated by observing multiple assemblies under controlled conditions.}, } @article {pmid28487997, year = {2017}, author = {Woo, SG and Lee, SM and Lee, SY and Lim, KH and Ha, EJ and Kim, SH and Eom, YB}, title = {The effectiveness of anti-biofilm and anti-virulence properties of dihydrocelastrol and dihydrocelastryl diacetate in fighting against methicillin-resistant Staphylococcus aureus.}, journal = {Archives of microbiology}, volume = {199}, number = {8}, pages = {1151-1163}, doi = {10.1007/s00203-017-1386-x}, pmid = {28487997}, issn = {1432-072X}, support = {20130793//Soonchunhyang University/ ; NRF- 2016H1D7A2020904//National Research Foundation of Korea/ ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Hemolysis ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Rabbits ; Staphylococcal Infections/drug therapy/prevention & control ; Triterpenes/*pharmacology ; Virulence/drug effects ; }, abstract = {Human pathogens have readily been converted into multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), because of the long-term use of conventional antibiotics. In addition, the biofilms formed by S. aureus cells are especially problematic and are related to the persistence of chronic infections because they constitute a major mechanism of promoting tolerance to diverse antimicrobial agents. Hence, the inhibitions of biofilm formation and/or toxin production are accepted as alternative means of controlling S. aureus infections. The present study was aimed at identifying novel anti-biofilm and/or anti-virulence compounds in friedelane-based pentacyclic triterpenoids present in many edible and medicinal plants-and investigating them against MRSA strains. As a result, dihydrocelastrol and dihydrocelastryl diacetate were found to both inhibit the biofilm formation of, and to disrupt the preformed biofilms of, MRSA strains to an increasingly greater degree with increasing concentrations of each compound. Furthermore, these two triterpenoids also clearly inhibited the hemolytic activity of MRSA-and in-line with their anti-biofilm activities, rendered the cell more hydrophilic. Additionally, corroborating phenotypic results, transcriptional analyses showed that both dihydrocelastrol and dihydrocelastryl diacetate disturbed the expression of gene related to α-hemolysin (hla) and down-regulated the expressions of the crucial biofilm-associated genes (agrA, sarA, ica, RNAIII, and rbf) in MRSA. The findings of this study suggest that friedelane-based pentacyclic triterpenoids-especially dihydrocelastrol and dihydrocelastryl diacetate-have the potential to be candidates both for use in controlling biofilm-related infections and for use as important components of anti-virulence strategies for fighting against MRSA infection.}, } @article {pmid28487780, year = {2017}, author = {Geremias, TC and Montero, JFD and Magini, RS and Schuldt Filho, G and de Magalhães, EB and Bianchini, MA}, title = {Biofilm Analysis of Retrieved Dental Implants after Different Peri-Implantitis Treatments.}, journal = {Case reports in dentistry}, volume = {2017}, number = {}, pages = {8562050}, pmid = {28487780}, issn = {2090-6447}, abstract = {The aim of the current study was to analyse the planktonic growth of Streptococcus mutans on the surfaces of three implants retrieved after three different peri-implantitis treatments. Three implants from a male patient with high levels of bone loss were treated by mechanical debridement, chemical decontamination, and implantoplasty. After 4 months of follow-up, the implants were removed. The growth and biofilm formation were measured by spectrophotometry (OD630 nm) and scanning electron microscopy (SEM), after 48 hours of incubation. Results showed an average of Streptococcus mutans planktonic growth over the implants of 0.21 nm (mechanical debridement), 0.16 nm (chemical decontamination), and 0.15 nm (implantoplasty). Data were analysed by ANOVA and Tukey's test (p < 0.05 for chemical decontamination and implantoplasty). Implantoplasty and chemical decontamination showed the lowest levels of planktonic growth, indicating a possible influence of the modification procedures on the titanium surface on the initial biofilm attachment.}, } @article {pmid28487228, year = {2017}, author = {Han, T and Li, Y and Shan, Q and Liang, W and Hao, W and Li, Y and Tan, X and Gu, J}, title = {Characterization of S-adenosylhomocysteine/Methylthioadenosine nucleosidase on secretion of AI-2 and biofilm formation of Escherichia coli.}, journal = {Microbial pathogenesis}, volume = {108}, number = {}, pages = {78-84}, doi = {10.1016/j.micpath.2017.05.015}, pmid = {28487228}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cloning, Molecular ; DNA, Bacterial ; Escherichia coli/enzymology/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Homoserine/*analogs & derivatives/metabolism ; Lactones/*metabolism ; Phenotype ; Purine-Nucleoside Phosphorylase/genetics/*metabolism ; Quorum Sensing/*physiology ; Recombinant Proteins/genetics ; S-Adenosylhomocysteine/*metabolism ; Sequence Deletion ; Virulence ; }, abstract = {S-adenosylhomocysteine/Methylthioadenosine nucleosidase (SAHN E.C.3.2.2.9) does not exist in mammalian cells but is essential for methyl recycling in numerous bacterial and protozoan species. Inhibition of this enzyme could limit synthesis of autoinducers of bacterial quorum sensing (QS), and hence, causes reduction in biofilm formation and may attenuate virulence. In this study, sahn deletion mutant of E. coli MG1655, sahn-complemented strain, and SANH-overexpressing strain were established and used to identify the secretion of autoinducer-2 (AI-2) and biofilm formation. The results indicated that deletion of the sahn gene abolished the production of the QS signal AI-2 and biofilm formation in mutant strain MG1655-Δsahn. And the complementation strain MG1655-Δsahn (pET-28a-sahn) showed restored production of AI-2 and biofilm formation, which indicates that the sahn gene plays an important role in bacterial quorum sensing. The recombinant SAHN protein was overexpressed and purified. The enzymatic activity of SAHN was successfully determined by a coupling-enzyme analysis based on xanthine oxidase, with the Vmax and Km of SAHN enzymatic reaction confirmed. Given that sahn is essential for the quorum sensing of both Gram-negative and Gram-positive bacteria, SAHN could be a potential target for wide-spectrum antibiotics.}, } @article {pmid28485690, year = {2018}, author = {Rossi, E and Cimdins, A and Lüthje, P and Brauner, A and Sjöling, Å and Landini, P and Römling, U}, title = {"It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment.}, journal = {Critical reviews in microbiology}, volume = {44}, number = {1}, pages = {1-30}, doi = {10.1080/1040841X.2017.1303660}, pmid = {28485690}, issn = {1549-7828}, mesh = {Animals ; *Biofilms ; Escherichia coli/genetics/*physiology ; Escherichia coli Proteins/genetics/metabolism ; Gastrointestinal Tract/immunology/*microbiology ; Gene Expression Regulation, Bacterial ; Humans ; }, abstract = {Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion. Although some major regulatory networks, adhesion factors and extracellular matrix components constituting E. coli biofilms have been recognized, these processes have mainly been characterized in vitro and in the context of interaction of E. coli strains with intestinal epithelial cells. However, direct observation of E. coli cells in situ, and the vast number of genes encoding surface appendages on the core or accessory genome of E. coli suggests the complexity of the biofilm process to be far from being fully understood. In this review, we summarize biofilm formation mechanisms of commensal, probiotic and pathogenic E. coli in the context of the gastrointestinal tract.}, } @article {pmid28485524, year = {2017}, author = {Wang, X and Li, X and Ling, J}, title = {Streptococcus gordonii LuxS/autoinducer-2 quorum-sensing system modulates the dual-species biofilm formation with Streptococcus mutans.}, journal = {Journal of basic microbiology}, volume = {57}, number = {7}, pages = {605-616}, doi = {10.1002/jobm.201700010}, pmid = {28485524}, issn = {1521-4028}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/drug effects/*growth & development ; Carbon-Sulfur Lyases/genetics/*metabolism ; Chlorhexidine/pharmacology ; Gene Expression Regulation, Bacterial ; Homoserine/*analogs & derivatives/biosynthesis/metabolism/pharmacology ; Lactones/*metabolism/pharmacology ; Mutation ; *Quorum Sensing ; Streptococcus gordonii/enzymology/genetics/*physiology ; Streptococcus mutans/*physiology ; Virulence/genetics ; }, abstract = {Dental plaques are mixed-species biofilms that are related to the development of dental caries. Streptococcus mutans (S. mutans) is an important cariogenic bacterium that forms mixed-species biofilms with Streptococcus gordonii (S. gordonii), an early colonizer of the tooth surface. The LuxS/autoinducer-2(AI-2) quorum sensing system is involved in the regulation of mixed-species biofilms, and AI-2 is proposed as a universal signal for the interaction between bacterial species. In this work, a S. gordonii luxS deficient strain was constructed to investigate the effect of the S. gordonii luxS gene on dual-species biofilm formed by S. mutans and S. gordonii. In addition, AI-2 was synthesized in vitro by incubating recombinant LuxS and Pfs enzymes of S. gordonii together. The effect of AI-2 on S. mutans single-species biofilm formation and cariogenic virulence gene expression were also assessed. The results showed that luxS disruption in S. gordonii altered dual-species biofilm formation, architecture, and composition, as well as the susceptibility to chlorhexidine. And the in vitro synthesized AI-2 had a concentration-dependent effect on S. mutans biofilm formation and virulence gene expression. These findings indicate that LuxS/AI-2 quorum-sensing system of S. gordonii plays a role in regulating the dual-species biofilm formation with S. mutans.}, } @article {pmid28484845, year = {2017}, author = {Barry, U and Choubert, JM and Canler, JP and Pétrimaux, O and Héduit, A and Lessard, P}, title = {A one dimensional moving bed biofilm reactor model for nitrification of municipal wastewaters.}, journal = {Bioprocess and biosystems engineering}, volume = {40}, number = {8}, pages = {1141-1149}, doi = {10.1007/s00449-017-1775-1}, pmid = {28484845}, issn = {1615-7605}, mesh = {*Biofilms ; Bioreactors ; Nitrification ; Nitrogen ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {This work presents a one-dimensional model of a moving bed bioreactor (MBBR) process designed for the removal of nitrogen from raw wastewaters. A comprehensive experimental strategy was deployed at a semi-industrial pilot-scale plant fed with a municipal wastewater operated at 10-12 °C, and surface loading rates of 1-2 g filtered COD/m[2] d and 0.4-0.55 g NH4-N/m[2] d. Data were collected on influent/effluent composition, and on measurement of key variables or parameters (biofilm mass and maximal thickness, thickness of the limit liquid layer, maximal nitrification rate, oxygen mass transfer coefficient). Based on time-course variations in these variables, the MBBR model was calibrated at two time-scales and magnitudes of dynamic conditions, i.e., short-term (4 days) calibration under dynamic conditions and long-term (33 days) calibration, and for three types of carriers. A set of parameters suitable for the conditions was proposed, and the calibrated parameter set is able to simulate the time-course change of nitrogen forms in the effluent of the MBBR tanks, under the tested operated conditions. Parameters linked to diffusion had a strong influence on how robustly the model is able to accurately reproduce time-course changes in effluent quality. Then the model was used to optimize the operations of MBBR layout. It was shown that the main optimization track consists of the limitation of the aeration supply without changing the overall performance of the process. Further work would investigate the influence of the hydrodynamic conditions onto the thickness of the limit liquid layer and the "apparent" diffusion coefficient in the biofilm parameters.}, } @article {pmid28484579, year = {2016}, author = {Mirza, YH and Tansey, R and Sukeik, M and Shaath, M and Haddad, FS}, title = {Biofilm and the Role of Antibiotics in the Treatment of Periprosthetic Hip and Knee Joint Infections.}, journal = {The open orthopaedics journal}, volume = {10}, number = {}, pages = {636-645}, pmid = {28484579}, issn = {1874-3250}, abstract = {An increasing demand for lower limb arthroplasty will lead to a proportionate increase in the need for revision surgery. A notable proportion of revision surgery is secondary to periprosthetic joint infections (PJI). Diagnosing and eradicating PJI can form a very difficult challenge. An important cause of PJI is the formation of a bacterial biofilm on the implant surface. Our review article seeks to describe biofilms; their definitions and formation, common causative bacteria, prophylactic and therapeutic antibiotic therapy.}, } @article {pmid28484515, year = {2017}, author = {Zhang, Q and Liu, C and Li, Y and Yu, Z and Chen, Z and Ye, T and Wang, X and Hu, Z and Liu, S and Xiao, B and Jin, S}, title = {Cultivation of algal biofilm using different lignocellulosic materials as carriers.}, journal = {Biotechnology for biofuels}, volume = {10}, number = {}, pages = {115}, pmid = {28484515}, issn = {1754-6834}, abstract = {BACKGROUND: Algal biofilm technology is recently supposed to be a promising method to produce algal biomass as the feedstock for the production of biofuels. However, the carrier materials currently used to form algal biofilm are either difficult to be obtained at a low price or undurable. Commercialization of the biofilm technology for algal biomass production extremely requires new and inexpensive materials as biofilm carriers with high biomass production performances.

RESULTS: Four types of lignocellulosic materials were investigated to evaluate their performance of acting as carriers for algal cells attachment and the relevant effects on the algal biomass production in this study. The cultivation of algal biofilm was processed in a self-designed flat plate photo-bioreactor. The biofilm production and chemical composition of the harvested biomass were determined. The surface physics properties of the materials were examined through a confocal laser-scanning microscopy. Algal biomass production varied significantly with the variation of the carriers (P < 0.05). All the lignocellulosic materials showed better performances in biofilm production than poly methyl methacrylate, and the application of pine sawdust as the carrier could gain the maximum biofilm productivity of 10.92 g m[-2] day[-1] after 16-day cultivation. In addition, 20.10-23.20% total lipid, 30.35-36.73% crude proteins, and 20.29-25.93% carbohydrate were achieved from the harvested biomasses. Biomass productivity increased linearly as the increase of surface roughness, and Wenzel's roughness factor of the tested materials, and surface roughness might significantly affect the biomass production through the size of surface morphology and the area of surface (P < 0.05).

CONCLUSIONS: The results showed that lignocellulosic materials can be efficient carriers for low-cost cultivation of algal biofilm and the enhancement of biomass productivity.}, } @article {pmid28484444, year = {2017}, author = {Husain, FM and Ahmad, I and Al-Thubiani, AS and Abulreesh, HH and AlHazza, IM and Aqil, F}, title = {Leaf Extracts of Mangifera indica L. Inhibit Quorum Sensing - Regulated Production of Virulence Factors and Biofilm in Test Bacteria.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {727}, pmid = {28484444}, issn = {1664-302X}, abstract = {Quorum sensing (QS) is a global gene regulatory mechanism in bacteria for various traits including virulence factors. Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Mangifera indica L. (mango) has been shown to possess various biological activities including anti-QS. This study investigates the efficacy of leaf extracts on QS-regulated virulence factors and biofilm formation in Gram negative pathogens. Mango leaf (ML) extract was tested for QS inhibition and QS-regulated virulence factors using various indicator strains. It was further correlated with the biofilm inhibition and confirmed by electron microscopy. Phytochemical analysis was carried out using ultra performance liquid chromatography (UPLC) and gas chromatography-mass spectrometry (GC-MS) analysis. In vitro evaluation of anti-QS activity of ML extracts against Chromobacterium violaceum revealed promising dose-dependent interference in violacein production, by methanol extract. QS inhibitory activity is also demonstrated by reduction in elastase (76%), total protease (56%), pyocyanin (89%), chitinase (55%), exopolysaccharide production (58%) and swarming motility (74%) in Pseudomonas aeruginosa PAO1 at 800 μg/ml concentration. Biofilm formation by P. aeruginosa PAO1 and Aeromonas hydrophila WAF38 was reduced considerably (36-82%) over control. The inhibition of biofilm was also observed by scanning electron microscopy. Moreover, ML extracts significantly reduced mortality of Caenorhabditis elegans pre-infected with PAO1 at the tested concentration. Phytochemical analysis of active extracts revealed very high content of phenolics in methanol extract and a total of 14 compounds were detected by GC-MS and UPLC. These findings suggest that phytochemicals from the ML could provide bioactive anti-infective and needs further investigation to isolate and uncover their therapeutic efficacy.}, } @article {pmid28483600, year = {2017}, author = {Fallah, F and Yousefi, M and Pourmand, MR and Hashemi, A and Nazari Alam, A and Afshar, D}, title = {Phenotypic and genotypic study of biofilm formation in Enterococci isolated from urinary tract infections.}, journal = {Microbial pathogenesis}, volume = {108}, number = {}, pages = {85-90}, doi = {10.1016/j.micpath.2017.05.014}, pmid = {28483600}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Chloramphenicol/pharmacology ; Drug Resistance, Bacterial ; Enterococcus/drug effects/*genetics/isolation & purification/*metabolism ; Enterococcus faecalis/drug effects/isolation & purification ; Enterococcus faecium/drug effects/isolation & purification ; Genes, Bacterial/genetics ; *Genotype ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; Iran ; Linezolid/pharmacology ; Microbial Sensitivity Tests ; Nitrofurantoin/pharmacology ; *Phenotype ; Polymerase Chain Reaction ; Urinary Tract Infections/drug therapy/*microbiology ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Urinary tract infection (UTI) is one of the most frequent types of nosocomial and community acquired infections in humans. Management of multidrug-resistant Enterococci UTI due to the limited therapeutic options is a great challenge for physicians and clinical microbiologists. The role of bacterial biofilms in recurrent urinary tract infections and antimicrobial resistance has great importance for public health. The aim of this study was to investigate the antibiotic susceptibility pattern as well as the phenotypic and genotypic biofilm formation ability of Enterococci isolates from patients with UTI.

METHODS: A total of 57 isolates of Enterococci were collected from patients with UTI. Enterococcus species were identified using conventional microbiological methods. The antibiotic susceptibility patterns of the isolates were determined by the Kirby-Bauer disk-diffusion. The Modified Congo red agar (MCRA) and Microtiter plate methods used to assess the ability of biofilm formation. All enterococcal isolates were examined for determination of biofilm-related genes, esp, asa1 and ebpR using PCR method.

RESULTS: Of 57 enterococcal isolates, 85.9% were recognized as E. faecalis and 14.1% of them were E. faecium. According to our results, linezolid, chloramphenicol and nitrofurantoin were the most effective agents against Enterococcus species. Overall, 26.5% of E. faecalis and 75% of E. faecium isolates were biofilm producers, respectively. Resistance to some antibiotics including penicillin G, ampicillin, vancomycin, nitrofurantoin and chloramphenicol, and ciprofloxacin was significantly higher among biofilm producers than non-biofilm producers Enterococci. The esp, asa1 and ebpR genes were present in 84.2%, 91.2% and 100% isolates. In this study, there was not a significant relationship between presence of these genes and biofilm formation.

CONCLUSION: Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Quinupristin/dalfopristin, tetracycline and rifampin may be used as an effective treatment for UTI caused by biofilm producers Enterococci. Our results suggest that biofilm formation is complex and depends on various factors but not just esp, asa1 and ebpR genes in Enterococcus strains.}, } @article {pmid28482286, year = {2017}, author = {Lan, S and Wu, L and Yang, H and Zhang, D and Hu, C}, title = {A new biofilm based microalgal cultivation approach on shifting sand surface for desert cyanobacterium Microcoleus vaginatus.}, journal = {Bioresource technology}, volume = {238}, number = {}, pages = {602-608}, doi = {10.1016/j.biortech.2017.04.058}, pmid = {28482286}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; *Cyanobacteria ; *Microalgae ; Photosynthesis ; }, abstract = {Biofilm based microalgal cultivation has recently received great attention because of its low water requirement and harvesting cost. However, the contradiction between microalgal attachment and harvesting still hinders the development of this technology. Therefore, in this study the most readily available and inexpensive shifting sand was used as attached substrate for microalgal (Microcoleus vaginatus) biofilm cultivation under different water conditions. After the inoculation, a stable and easily peeled microalgal biofilm formed through filamentous binding and exopolysaccharide cementing. In general, microalgal biomass, photosynthetic activity and exopolysaccharide accumulation were all significantly affected by the cultivation time, water content and their interaction (P<0.001). According to the maximal photosynthetic activity and microalgal productivity, cultivation time of microalgal biofilm on sand surface should be controlled around 15-25days, with water content at 10%. Based on the biofilm cultivation system, microalgal biomass yield reached up to 11gm[-2] eventually on the sand surface.}, } @article {pmid28482226, year = {2017}, author = {Thomas, R and Mathew, S and Nayana, AR and Mathews, J and Radhakrishnan, EK}, title = {Microbially and phytofabricated AgNPs with different mode of bactericidal action were identified to have comparable potential for surface fabrication of central venous catheters to combat Staphylococcus aureus biofilm.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {171}, number = {}, pages = {96-103}, doi = {10.1016/j.jphotobiol.2017.04.036}, pmid = {28482226}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Central Venous Catheters/microbiology ; Metal Nanoparticles/chemistry/*toxicity/ultrastructure ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Silver/*chemistry ; Staphylococcus aureus/*physiology ; Surface Properties ; }, abstract = {In spite of newer innovations and process improvements, catheter related infections still pose serious threat to hospitalized patients. Silver nanoparticles (AgNPs) are well demonstrated to have antibacterial properties and also have been implemented for surface fabrication of many indwelling medical devices. So, herein we sought to compare the performance of AgNPs generated through biogenic routes using bacteria and plant extract for their antibacterial and antibiofilm potential against biofilm forming Staphylococcus aureus. The biosynthesized AgNPs were characterized by UV- Visible spectroscopy, HR-TEM and EDS analysis. The antibacterial efficiency of the nanoparticles was detected by Disc diffusion assay, MIC and MBC analysis. The antibiofilm properties of the nanoparticles were also investigated. The antibacterial mode of interaction of both nanoparticles on the bacterium was analyzed by HR-TEM. Insight into mode of interaction and mechanism of antibacterial activity of both AgNPs showed them to have promises for surface fabrication of central venous catheters. No study has been conducted so far to compare the efficiency of two different biogenic AgNPs and this highlights the novelty of the current work. Though both AgNPs were observed to exhibit comparable activity in terms of bactericidal and antibiofilm, the mode of bacterial interaction and degree of damage caused was entirely different.}, } @article {pmid28481506, year = {2017}, author = {Guo, Q and Zhao, Y and Dai, X and Zhang, T and Yu, Y and Zhang, X and Li, C}, title = {Functional Silver Nanocomposites as Broad-Spectrum Antimicrobial and Biofilm-Disrupting Agents.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {20}, pages = {16834-16847}, doi = {10.1021/acsami.7b02775}, pmid = {28481506}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Microbial Sensitivity Tests ; *Nanocomposites ; Staphylococcus aureus ; }, abstract = {Biofilms' tolerance has become a serious clinical concern due to their formidable resistance to conventional antibiotics and prevalent virulence. Therefore, there is an urgent need to develop alternative antimicrobial agents to eradicate biofilms but avoid using antibiotics. Herein, we successfully developed polymer functional silver nanocomposites by reduction of silver nitrate in the presence of a biocompatible carbohydrate polymer and a membrane-disrupting cationic polymer. The nanocomposites presented effective antimicrobial activity against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus and Bacillus amyloliquefaciens). Confocal laser scanning macroscopy imaging demonstrated that the nanocomposites could efficiently disperse and eradicate the mature biofilms formed by the above four bacterial strains. The introduction of carbohydrate polymers onto nanocomposites effectively improved the biocompatibility, and these nanocomposites induced no significant red blood cell hemolysis and cytotoxicity toward mammalian cells. More importantly, the nanocomposites were able to well eradicate the bacterial biofilms formed on the silicone implants in vivo. In conclusion, the nanocomposites as the broad-spectrum biofilm-disrupting agent are significant in the design of new strategies to eradicate biofilms on indwelling medical devices.}, } @article {pmid28481197, year = {2017}, author = {Szczuka, E and Jabłońska, L and Kaznowski, A}, title = {Effect of subinhibitory concentrations of tigecycline and ciprofloxacin on the expression of biofilm-associated genes and biofilm structure of Staphylococcus epidermidis.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {5}, pages = {712-718}, pmid = {28481197}, issn = {1465-2080}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/biosynthesis/genetics ; Biofilms/drug effects/*growth & development ; Ciprofloxacin/*pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Minocycline/*analogs & derivatives/pharmacology ; N-Acetylmuramoyl-L-alanine Amidase/biosynthesis/genetics ; RNA, Messenger/genetics ; Sigma Factor/biosynthesis/genetics ; Staphylococcus epidermidis/*drug effects/genetics/isolation & purification/*metabolism ; Tigecycline ; Transferases/biosynthesis/genetics ; }, abstract = {Staphylococcus epidermidis is a leading cause of foreign body-associated infections. This is related to the bacterium's ability to form biofilms on synthetic materials. Bacteria within a biofilm may be exposed to subinhibitory concentrations (sub-MICs) of antibiotics because of an agent's limited penetration into the biofilm core. Here, we investigated the effect of sub-MICs of tigecycline and ciprofloxacin on the expression of biofilm-associated genes, i.e. icaA, altE and sigB, and the biofilm structure of five clinical isolates of S. epidermidis. For most tested isolates, the expression of these genes increased after exposure to 0.25 MIC and 0.5 MIC tigecycline. A slight decrease in icaAmRNA levels was observed only in two isolates in the presence of 0.25 MIC tigecycline. The effect of ciprofloxacin exposure was isolate-dependent. At 0.5 MIC, ciprofloxacin induced an increase of sigB and icaAmRNA levels in three of the five tested isolates. At the same time, expression of the altE gene increased in all isolates (from 1.3-fold to 42-fold, depending on the strain). Confocal laser scanning microscopy analysis indicated that sub-MIC ciprofloxacin decreased biofilm formation, whereas tigecycline stimulated this process. Our data suggest that sub-MIC tigecycline may have bearing on the outcome of infections.}, } @article {pmid29251900, year = {2016}, author = {Liu, W and Yuan, L and Wei, B}, title = {Study on improvement of continuous hydrogen production by photosynthetic biofilm in interior illuminant reactor.}, journal = {Journal of environmental biology}, volume = {37}, number = {5}, pages = {999-1006}, pmid = {29251900}, issn = {0254-8704}, mesh = {*Biofilms ; Bioreactors ; Hydrogen/*metabolism ; Light ; *Photosynthesis ; Rhodopseudomonas/*metabolism ; Time Factors ; }, abstract = {In the present study, a new type of interior optical fiber illuminating reactor was developed for H2 production to solve the problem of luminous intensity attenuation at the center portion of a reactor, and an immobilization technique was used to enhance the stability of a continuous hydrogen production process with attached photosynthetic bacteria, using glucose as a sole carbon substrate for the indigenous photosynthetic bacteria (PSB) Rhodopseudomonas palustris SP-6. Results of the experiments showed that the interior optical fiber illuminating reactor produces H2 more efficiently and productively than the exterior light source reactor, with the cumulative H2 production, the maximum H2 production rate and H2 yield increased by 813ml, 11.3ml l-1 h-1 and 22.3%, respectively. The stability of the product of continuous hydrogen was realized by immobilizing PSB on the surface of powder active carbon(PAC). After adding the dosage of 2.0g l-1 PAC, the continuous steady operation of H2 production gave a high H2 yield of 1.398 mol H2 mol-1 glucose and an average H2 production rate of 35.1ml l-1 h-1 illuminating with a single interior optical fiber light source. Meanwhile, a higher H2 yield of 1.495 mol H2 mol-1 glucose and an average H2 production rate of 38.7ml l-1 h-1 were attained illuminating with a compound lamp in the continuous H2 production for 20 days.}, } @article {pmid29242685, year = {2016}, author = {de Medeiros, AKB and de Melo, LA and Alves, RAH and Barbosa, GAS and de Lima, KC and Porto Carreiro, ADF}, title = {Inhibitory effect of cranberry extract on periodontopathogenic biofilm: An integrative review.}, journal = {Journal of Indian Society of Periodontology}, volume = {20}, number = {5}, pages = {503-508}, pmid = {29242685}, issn = {0972-124X}, abstract = {BACKGROUND: Combating biofilm-dependent oral infections involves the use of synthetic antibiotics, which are often associated with bacterial resistance and adverse effects. As a result, herbs such as cranberry have emerged as an alternative treatment. The aim of this study was to evaluate, through an integrative literature review, the effectiveness of cranberry extract on cultures and biofilms of periodontopathogenic bacteria.

MATERIALS AND METHODS: In vitro and in vivo studies evaluating the action of cranberry extract on the growth, coaggregation and formation of periodontopathogenic bacteria and periodontal biofilm were identified. Searches were carried out in the "Cochrane Library," "MEDLINE," "Web of Science," "Scopus," "LILACS," "Scielo," and "Google Scholar" databases, using the terms: "vaccinium macrocarpon;" "cranberries;" "cranberry;" "biofilms;" "periodontitis;" "chronic periodontitis;" "aggressive periodontitis;" "periodontal diseases;" and "periodont*."

RESULTS: a low number of studies evaluating the effectiveness of cranberry extract on periodontal disease were found, and no human studies were identified. In general, the eight studies included in the revision found that the compounds effectively inhibited the formation of a biofilm of Porphyromonas gingivalis and Fusobacterium nucleatum at concentrations equal or superior to 62.5 μg/ml, but did not significantly inhibit bacterial growth or promote the breakdown of preformed biofilm.

CONCLUSIONS: while most of the studies presented certain methodological limitations, they did identify an inhibiting effect of cranberry on periodontal bacteria. These results serve as support for the development of further studies evaluating the most effective vehicle and ideal concentration that can be used without causing adverse effects on oral tissues.}, } @article {pmid29027847, year = {2016}, author = {Kim, H and Izadjoo, M}, title = {Antimicrobial activity of a bioelectric dressing using an in vitro wound pathogen colony drip-flow reactor biofilm model.}, journal = {Journal of wound care}, volume = {25}, number = {Sup7}, pages = {S47-S52}, doi = {10.12968/jowc.2016.25.Sup7.S47}, pmid = {29027847}, issn = {0969-0700}, mesh = {Anti-Infective Agents ; *Bacterial Physiological Phenomena ; Bandages ; Biofilms/*growth & development ; *Electric Stimulation Therapy ; Humans ; Silver ; Wound Healing/*physiology ; Wound Infection/*microbiology/*therapy ; Zinc ; }, abstract = {OBJECTIVE: We performed in vitro antibiofilm testing of a silver and zinc containing microcurrent generating bioelectric dressing (BED) against clinical wound pathogens to determine its efficacy in preventing biofilm formation under low shear and continuous flow conditions, simulating wound infection environments.

METHOD: We customised an in vitro colony drip-flow reactor (DFR) biofilm model for efficacy evaluation of BED. Each bacterial pathogen was diluted to 10[4]CFU/ml and inoculated on the polycarbonate filter membrane as an abiotic support. BED and controls (no treatment, gauze, and blank polyester with no silver and zinc) were applied directly on the membranes where bacterial cultures were inoculated. Biofilms were continuously developed onto the membranes for 72 hours at room temperature. Biofilm formation was confirmed by crystal violet staining and microscopic observation. Through vigorous shaking and sonication, the released bacteria were serially diluted, plated, and incubated for 24 hours at 37°C to determine the numbers of surviving bacteria.

RESULTS: Biofilms were well developed onto blank polyesters, but not the BED after 72 hours incubation. Crystal violet staining from the blank polyesters showed large and fully grown biofilms. We observed an inhibition in bacterial growth on BED treatment. The antibiofilm activity of the BED against each of eight monospecies biofilms showed a 1- or 2 log10 (or 10- or 100-fold) reduction in bacterial numbers compared with those of controls.

CONCLUSION: Our results demonstrated that colony DFR biofilm model was an appropriate for testing the antibiofilm efficacy of BED under low shear and continuous flow conditions for simulating clinical wound environments. The bioelectric currents generated from the silver and zinc active ingredients in the dressing resulted in antibiofilm activity of this wound care device.

DECLARATION OF INTEREST: The opinions or assertions contained herein are the private views of the authors, based on scientific investigation, and are not to be construed as official or as reflecting the views of the Department of Defense, the United States Government or any of the authors' employers. Dr. Mina Izadjoo has served as a consultant to Vomaris Innovations Inc.}, } @article {pmid28773540, year = {2016}, author = {Nocelli, N and Bogino, PC and Banchio, E and Giordano, W}, title = {Roles of Extracellular Polysaccharides and Biofilm Formation in Heavy Metal Resistance of Rhizobia.}, journal = {Materials (Basel, Switzerland)}, volume = {9}, number = {6}, pages = {}, pmid = {28773540}, issn = {1996-1944}, abstract = {Bacterial surface components and extracellular compounds, particularly flagella, lipopolysaccharides (LPSs), and exopolysaccharides (EPSs), in combination with environmental signals and quorum-sensing signals, play crucial roles in bacterial autoaggregation, biofilm development, survival, and host colonization. The nitrogen-fixing species Sinorhizobium meliloti (S. meliloti) produces two symbiosis-promoting EPSs: succinoglycan (or EPS I) and galactoglucan (or EPS II). Studies of the S.meliloti/alfalfa symbiosis model system have revealed numerous biological functions of EPSs, including host specificity, participation in early stages of host plant infection, signaling molecule during plant development, and (most importantly) protection from environmental stresses. We evaluated functions of EPSs in bacterial resistance to heavy metals and metalloids, which are known to affect various biological processes. Heavy metal resistance, biofilm production, and co-culture were tested in the context of previous studies by our group. A range of mercury (Hg II) and arsenic (As III) concentrations were applied to S. meliloti wild type strain and to mutant strains defective in EPS I and EPS II. The EPS production mutants were generally most sensitive to the metals. Our findings suggest that EPSs are necessary for the protection of bacteria from either Hg (II) or As (III) stress. Previous studies have described a pump in S. meliloti that causes efflux of arsenic from cells to surrounding culture medium, thereby protecting them from this type of chemical stress. The presence of heavy metals or metalloids in culture medium had no apparent effect on formation of biofilm, in contrast to previous reports that biofilm formation helps protect various microorganism species from adverse environmental conditions. In co-culture experiments, EPS-producing heavy metal resistant strains exerted a protective effect on AEPS-non-producing, heavy metal-sensitive strains; a phenomenon termed "rescuing" of the non-resistant strain.}, } @article {pmid28721244, year = {2016}, author = {Kaushik, KS and Stolhandske, J and Shindell, O and Smyth, HD and Gordon, VD}, title = {Tobramycin and bicarbonate synergise to kill planktonic Pseudomonas aeruginosa, but antagonise to promote biofilm survival.}, journal = {NPJ biofilms and microbiomes}, volume = {2}, number = {}, pages = {16006}, pmid = {28721244}, issn = {2055-5008}, abstract = {Increasing antibiotic resistance and the declining rate at which new antibiotics come into use create a need to increase the efficacy of existing antibiotics. The aminoglycoside tobramycin is standard-of-care for many types of Pseudomonas aeruginosa infections, including those in the lungs of cystic fibrosis (CF) patients. P. aeruginosa is a nosocomial and opportunistic pathogen that, in planktonic form, causes acute infections and, in biofilm form, causes chronic infections. Inhaled bicarbonate has recently been proposed as a therapy to improve antimicrobial properties of the CF airway surface liquid and viscosity of CF mucus. Here we measure the effect of combining tobramycin and bicarbonate against P. aeruginosa, both lab strains and CF clinical isolates. Bicarbonate synergises with tobramycin to enhance killing of planktonic bacteria. In contrast, bicarbonate antagonises with tobramycin to promote better biofilm growth. This suggests caution when evaluating bicarbonate as a therapy for CF lungs infected with P. aeruginosa biofilms. We analyse tobramycin and bicarbonate interactions using an interpolated surface methodology to measure the dose-response function. These surfaces allow more accurate estimation of combinations yielding synergy and antagonism than do standard isobolograms. By incorporating predictions based on Loewe additivity theory, we can consolidate information on a wide range of combinations that produce a complex dose-response surface, into a single number that measures the net effect. This tool thus allows rapid initial estimation of the potential benefit or harm of a therapeutic combination. Software code is freely made available as a resource for the community.}, } @article {pmid28773281, year = {2016}, author = {Lin, WT and Zhang, YY and Tan, HL and Ao, HY and Duan, ZL and He, G and Tang, TT}, title = {Inhibited Bacterial Adhesion and Biofilm Formation on Quaternized Chitosan-Loaded Titania Nanotubes with Various Diameters.}, journal = {Materials (Basel, Switzerland)}, volume = {9}, number = {3}, pages = {}, pmid = {28773281}, issn = {1996-1944}, abstract = {Titania nanotube-based local drug delivery is an attractive strategy for combating implant-associated infection. In our previous study, we demonstrated that the gentamicin-loaded nanotubes could dramatically inhibit bacterial adhesion and biofilm formation on implant surfaces. Considering the overuse of antibiotics may lead to the evolution of antibiotic-resistant bacteria, we synthesized a new quaternized chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) with a 27% degree of substitution (DS; referred to as 27% HACC) that had a strong antibacterial activity and simultaneously good biocompatibility with osteogenic cells. Titania nanotubes with various diameters (80, 120, 160, and 200 nm) and 200 nm length were loaded with 2 mg of HACC using a lyophilization method and vacuum drying. Two standard strain, methicillin-resistant Staphylococcus aureus (American Type Culture Collection 43300) and Staphylococcus epidermidis (American Type Culture Collection 35984), and two clinical isolates, S. aureus 376 and S. epidermidis 389, were selected to investigate the bacterial adhesion at 6 h and biofilm formation at 24, 48, and 72 h on the HACC-loaded nanotubes (NT-H) using the spread plate method, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). Smooth titanium (Smooth Ti) was also investigated and compared. We found that NT-H could significantly inhibit bacterial adhesion and biofilm formation on its surface compared with Smooth Ti, and the NT-H with 160 nm and 200 nm diameters had stronger antibacterial activity because of the extended HACC release time of NT-H with larger diameters. Therefore, NT-H can significantly improve the antibacterial ability of orthopedic implants and provide a promising strategy to prevent implant-associated infections.}, } @article {pmid28721237, year = {2015}, author = {De Weirdt, R and Van de Wiele, T}, title = {Micromanagement in the gut: microenvironmental factors govern colon mucosal biofilm structure and functionality.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15026}, pmid = {28721237}, issn = {2055-5008}, abstract = {The human gut microbiome provides us with functional features that we did not have to evolve ourselves and can be viewed as a structured microbial community that operates like a microbial organ within the human host. A minor but important part of this microbiome is the ability to colonise and thrive within the mucous layer that covers the colon epithelium. These mucosal microbes intimately interact with the intestinal tissue and seem to be important modulators of human health. Embedded in the host-secreted mucous matrix, they form a 'mucosal biofilm' with a distinct composition and functionality. In this review, we provide evidence that six specific (micro)environmental factors near the colon mucosa shape and determine mucosal biofilm formation and stability, that is, (1) mucous rigidity, (2) gradients of fluid shear, (3) radial oxygen gradients, (4) secretions of host defense molecules, (5) the presence of a rich but challenging nutrient platform and (6) the presence of niches at the colon epithelial surface. In addition, it appears that microbes actively participate in shaping their mucosal environment. Current insights into the interaction between mucosal microbes and their environment are rather limited, and many questions regarding the contribution of mucosal biofilm functionality and stability to human health remain to be answered. Yet, given the higher potency of mucosal microbes than their luminal counterparts to interact with the host, new insights can accelerate the development of novel disease-preventive or therapeutic strategies.}, } @article {pmid29104889, year = {2015}, author = {Zheng, H and Keller, NP and Wang, Y}, title = {Establishing a Biofilm Co-culture of Pseudomonas and Aspergillus for Metabolite Extraction.}, journal = {Bio-protocol}, volume = {5}, number = {23}, pages = {}, pmid = {29104889}, issn = {2331-8325}, support = {R01 GM067725/GM/NIGMS NIH HHS/United States ; }, abstract = {Filamentous fungi and bacteria form mixed-species biofilms in nature and diverse clinical contexts (Frey-Klett et al., 2011; Peleg et al., 2010). The interactions between fungi and bacteria, often mediated by secreted metabolites, have important ramifications for the biology of the interacting partners (Frey-Klett et al., 2011). This is particularly true for the bacterium Pseudomonas aeruginosa (P. aeruginosa) and the fungus Aspergillus fumigatus (A. fumigatus) which often reside in the same niche such as lungs of cystic fibrosis (CF) patients. Some studies have reported that co-infection with P. aeruginosa and A. fumigatus could lead to a decrease in lung function relative to their respective single species infection (Amin et al., 2010; Peleg et al., 2010). Metabolite extraction and analysis allow for the characterization of specific microbial metabolites in the polymicrobial biofilm. This protocol describes how to prepare the Pseudomonas-Aspergillus co-culture biofilm on solid medium in preparation for metabolite extraction.}, } @article {pmid28721236, year = {2015}, author = {Feng, G and Cheng, Y and Wang, SY and Borca-Tasciuc, DA and Worobo, RW and Moraru, CI}, title = {Bacterial attachment and biofilm formation on surfaces are reduced by small-diameter nanoscale pores: how small is small enough?.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15022}, pmid = {28721236}, issn = {2055-5008}, support = {S10 RR025502/RR/NCRR NIH HHS/United States ; }, abstract = {BACKGROUND/OBJECTIVES: Prevention of biofilm formation by bacteria is of critical importance to areas that directly affect human health and life including medicine, dentistry, food processing and water treatment. This work showcases an effective and affordable solution for reducing attachment and biofilm formation by several pathogenic bacteria commonly associated with foodborne illnesses and medical infections.

METHODS: Our approach exploits anodisation to create alumina surfaces with cylindrical nanopores with diameters ranging from 15 to 100 nm, perpendicular to the surface. The anodic surfaces were evaluated for attachment by Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus epidermidis. Cell-surface interaction forces were calculated and related to attachment.

RESULTS: We found that anodic alumina surfaces with pore diameters of 15 and 25 nm were able to effectively minimise bacterial attachment or biofilm formation by all the microorganisms tested. Using a predictive physicochemical approach on the basis of the extended Derjaguin and Landau, Verwey and Overbeek (XDLVO) theory, we attributed the observed effects largely to the repulsive forces, primarily electrostatic and acid-base forces, which were greatly enhanced by the large surface area originating from the high density, small-diameter pores. We also demonstrate how this predictive approach could be used to optimise different elements of surface topography, particularly pore diameter and density, for further enhancing the observed bacteria-repelling effects.

CONCLUSIONS: We demonstrate that anodic nanoporous surfaces can effectively reduce bacterial attachment. These findings are expected to have immediate, far-reaching implications and commercial applications, primarily in health care and the food industry.}, } @article {pmid28721233, year = {2015}, author = {Kim, YW and Subramanian, S and Gerasopoulos, K and Ben-Yoav, H and Wu, HC and Quan, D and Carter, K and Meyer, MT and Bentley, WE and Ghodssi, R}, title = {Effect of electrical energy on the efficacy of biofilm treatment using the bioelectric effect.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15016}, pmid = {28721233}, issn = {2055-5008}, abstract = {BACKGROUND/OBJECTIVES: The use of electric fields in combination with small doses of antibiotics for enhanced treatment of biofilms is termed the 'bioelectric effect' (BE). Different mechanisms of action for the AC and DC fields have been reported in the literature over the last two decades. In this work, we conduct the first study on the correlation between the electrical energy and the treatment efficacy of the bioelectric effect on Escherichia coli K-12 W3110 biofilms.

METHODS: A thorough study was performed through the application of alternating (AC), direct (DC) and superimposed (SP) potentials of different amplitudes on mature E. coli biofilms. The electric fields were applied in combination with the antibiotic gentamicin (10 μg/ml) over a course of 24 h, after the biofilms had matured for 24 h. The biofilms were analysed using the crystal violet assay, the colony-forming unit method and fluorescence microscopy.

RESULTS: Results show that there is no statistical difference in treatment efficacy between the DC-, AC- and SP-based BE treatment of equivalent energies (analysis of variance (ANOVA) P>0.05) for voltages <1 V. We also demonstrate that the efficacy of the BE treatment as measured by the crystal violet staining method and colony-forming unit assay is proportional to the electrical energy applied (ANOVA P<0.05). We further verify that the treatment efficacy varies linearly with the energy of the BE treatment (r[2] =0.984). Our results thus suggest that the energy of the electrical signal is the primary factor in determining the efficacy of the BE treatment, at potentials less than the media electrolysis voltage.

CONCLUSIONS: Our results demonstrate that the energy of the electrical signal, and not the type of electrical signal (AC or DC or SP), is the key to determine the efficacy of the BE treatment. We anticipate that this observation will pave the way for further understanding of the mechanism of action of the BE treatment method and may open new doors to the use of electric fields in the treatment of bacterial biofilms.}, } @article {pmid28721232, year = {2015}, author = {Connolly, JM and Jackson, B and Rothman, AP and Klapper, I and Gerlach, R}, title = {Estimation of a biofilm-specific reaction rate: kinetics of bacterial urea hydrolysis in a biofilm.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15014}, pmid = {28721232}, issn = {2055-5008}, abstract = {BACKGROUND/OBJECTIVES: Biofilms and specifically urea-hydrolysing biofilms are of interest to the medical community (for example, urinary tract infections), scientists and engineers (for example, microbially induced carbonate precipitation). To appropriately model these systems, biofilm-specific reaction rates are required. A simple method for determining biofilm-specific reaction rates is described and applied to a urea-hydrolysing biofilm.

METHODS: Biofilms were grown in small silicon tubes and influent and effluent urea concentrations were determined. Immediately after sampling, the tubes were thin sectioned to estimate the biofilm thickness profile along the length of the tube. Urea concentration and biofilm thickness data were used to construct an inverse model for the estimation of the urea hydrolysis rate.

RESULTS/CONCLUSIONS: It was found that urea hydrolysis in Escherichia coli MJK2 biofilms is well approximated by first-order kinetics between urea concentrations of 0.003 and 0.221 mol/l (0.186 and 13.3 g/l). The first-order rate coefficient (k1) was estimated to be 23.2±6.2 h[-1]. It was also determined that advection dominated the experimental system rather than diffusion, and that urea hydrolysis within the biofilms was not limited by diffusive transport. Beyond the specific urea-hydrolysing biofilm discussed in this work, the method has the potential for wide application in cases where biofilm-specific rates must be determined.}, } @article {pmid28748199, year = {2015}, author = {van Tilburg Bernardes, E and Lewenza, S and Reckseidler-Zenteno, S}, title = {Current Research Approaches to Target Biofilm Infections.}, journal = {Postdoc journal : a journal of postdoctoral research and postdoctoral affairs}, volume = {3}, number = {6}, pages = {36-49}, pmid = {28748199}, issn = {2328-9791}, support = {R21 AI098701/AI/NIAID NIH HHS/United States ; R33 AI098701/AI/NIAID NIH HHS/United States ; }, abstract = {This review will focus on strategies to develop new treatments that target the biofilm mode of growth and that can be used to treat biofilm infections. These approaches aim to reduce or inhibit biofilm formation, or to increase biofilm dispersion. Many antibiofilm compounds are not bactericidal but render the cells in a planktonic growth state, which are more susceptible to antibiotics and more easily cleared by the immune system. Novel compounds are being developed with antibiofilm activity that includes antimicrobial peptides, natural products, small molecules and polymers. Bacteriophages are being considered for use in treating biofilms, as well as the use of enzymes that degrade the extracellular matrix polymers to dissolve biofilms. There is great potential in these new approaches for use in treating chronic biofilm infections.}, } @article {pmid28721230, year = {2015}, author = {Tan, CH and Koh, KS and Xie, C and Zhang, J and Tan, XH and Lee, GP and Zhou, Y and Ng, WJ and Rice, SA and Kjelleberg, S}, title = {Community quorum sensing signalling and quenching: microbial granular biofilm assembly.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15006}, pmid = {28721230}, issn = {2055-5008}, abstract = {BACKGROUND: Recent reports exploring the role of gradients of quorum sensing (QS) signals in functional activated sludge have raised the question of whether shared systems of signalling synthesis and degradation, or quorum quenching (QQ), across the community inform of the means by which QS biology regulate floccular and granular biofilm assembly.

AIMS: In this study, we aimed to explore the species origin and interactive role of QS and QQ activities in such highly diverse microbial biofilm communities.

METHODS: Here, such aims were addressed systematically by a comprehensive multi-pronged RNA-sequencing, microbiological and analytical chemistry experimental approach, using two related but independently evolved floccular and granular sludge communities.

RESULTS: Our data revealed a distinct difference between the QS and QQ potentials of the two communities, with different species largely displaying either QS or QQ functions. The floccular sludge community showed a high rate of QQ activity, and this rate was dependent on the acyl chain length demonstrating specificity of degradation. When the floccular biomass was transformed into the granular sludge, the QQ activity of the community was reduced by 30%. N-acyl homoserine lactones with four to eight carbons on the acyl chain accumulated at the granular stage, and their concentrations were at least threefold higher than those of the floccular stage. These findings corroborated meta-community analysis where a major shift in the dominant species from potential signal quenchers to producers was observed during the transition from flocs to granules, indicating the role of species composition and associated signalling activities in coordinating community behaviours.

CONCLUSIONS: This study suggests that QQ has an important function in regulating community level QS signalling, and provides a mechanistic insight into the role of QS biology in complex community assembly.}, } @article {pmid28721226, year = {2015}, author = {Battin, TJ}, title = {Chartering new waters of biofilm ecology and evolution.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15002}, doi = {10.1038/npjbiofilms.2015.2}, pmid = {28721226}, issn = {2055-5008}, } @article {pmid29082279, year = {2015}, author = {Maierl, M and Jörger, M and Rosker, P and Reisner, A}, title = {In vitro Dynamic Model of a Catheterized Bladder and Biofilm Assay.}, journal = {Bio-protocol}, volume = {5}, number = {2}, pages = {}, pmid = {29082279}, issn = {2331-8325}, support = {P 21434/FWF_/Austrian Science Fund FWF/Austria ; }, abstract = {Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI) which represent the most frequent nosocomial infections. Understanding of factors relevant for CAUTI pathogenesis and evaluation of new therapeutics or interference strategies requires a model system that mirrors the physico-chemical conditions prevailing in a catheterized human bladder. The described in vitro dynamic model of a catheterized bladder enables to emulate many of the characteristics of a catheterized human bladder albeit in the absence of a bladder epithelium. A minor modification compared to the original model system (Stickler, et al., 1999) allows temperature maintenance of the top 10 cm of the catheter, thereby enabling reproducible monitoring of biofilm formation on the internal catheter surface.}, } @article {pmid28788641, year = {2014}, author = {de Avila, ED and de Molon, RS and Vergani, CE and de Assis Mollo, F and Salih, V}, title = {The Relationship between Biofilm and Physical-Chemical Properties of Implant Abutment Materials for Successful Dental Implants.}, journal = {Materials (Basel, Switzerland)}, volume = {7}, number = {5}, pages = {3651-3662}, pmid = {28788641}, issn = {1996-1944}, abstract = {The aim of this review was to investigate the relationship between biofilm and peri-implant disease, with an emphasis on the types of implant abutment surfaces. Individuals with periodontal disease typically have a large amount of pathogenic microorganisms in the periodontal pocket. If the individuals lose their teeth, these microorganisms remain viable inside the mouth and can directly influence peri-implant microbiota. Metal implants offer a suitable solution, but similarly, these remaining bacteria can adhere on abutment implant surfaces, induce peri-implantitis causing potential destruction of the alveolar bone near to the implant threads and cause the subsequent loss of the implant. Studies have demonstrated differences in biofilm formation on dental materials and these variations can be associated with both physical and chemical characteristics of the surfaces. In the case of partially edentulous patients affected by periodontal disease, the ideal type of implant abutments utilized should be one that adheres the least or negligible amounts of periodontopathogenic bacteria. Therefore, it is of clinically relevance to know how the bacteria behave on different types of surfaces in order to develop new materials and/or new types of treatment surfaces, which will reduce or inhibit adhesion of pathogenic microorganisms, and, thus, restrict the use of the abutments with indication propensity for bacterial adhesion.}, } @article {pmid28509153, year = {2012}, author = {Kusaba, T and Kirita, Y and Ishida, R and Matsuoka, E and Nakayama, M and Uchiyama, H and Kajita, Y}, title = {Morphological analysis of biofilm of peritoneal dialysis catheter in refractory peritonitis patient.}, journal = {CEN case reports}, volume = {1}, number = {1}, pages = {50-54}, pmid = {28509153}, issn = {2192-4449}, abstract = {A 66-year-old man undergoing peritoneal dialysis (PD) was admitted to our hospital for treatment of PD-related peritonitis. Culture of the PD fluid revealed the presence of Citrobacter freundii, and therapy with ceftazidime was started intraperitoneally. The cell count in PD fluid slowly decreased over time during the first 2 weeks of treatment, but increased again on the 14th hospital day. A second culture of the PD fluid revealed the presence of Enterococcus species. A switch in antibiotic therapy to vancomycin did not improve the cell count in the PD fluid. A third culture of the PD fluid revealed the presence of Stenotrophomonas maltophilia. The PD was discontinued and the catheter removed on the 28th hospital day. Examination of the catheter revealed that the inner tip was coated with a fibrous sheet of cells, suggesting biofilm formation. Following catheter removal, the patient was administered intravenous ciprofloxacin, and the inflammatory reaction started to disappear immediately and had completely disappeared after 1 week of treatment. Microscopic analysis of the fibrous structure on the catheter revealed multiple layers of various inflammatory cells. Immunostaining revealed the presence of CD44-positive polynuclear cells, indicating neutrophils, facing the catheter lumen. CD68-positive cells, indicating macrophages, were observed in the following layer, and keratin-positive cells, indicating peritoneal mesothelial cells, were present at the bottom of the structure. Based on the immediate improvement of PD-related peritonitis after catheter removal, we presumed that this biofilm contributed to the intractability of the patient's peritonitis. Morphological analysis of catheter revealed that both the mesothelial cells and the various inflammatory cells may have contributed to biofilm development.}, } @article {pmid29149526, year = {2010}, author = {Ciancio, S}, title = {Biofilm dynamics at the gingival frontier.}, journal = {International dental journal}, volume = {60}, number = {3S1}, pages = {200-203}, doi = {10.1922/IDJ_2557Ciancio}, pmid = {29149526}, issn = {1875-595X}, abstract = {Microbial biofilms are common in the human body and in the environment. In recent years, dental plaque has been identified as a biofilm, and the structure, microbiology, and pathophysiology of dental biofilms have been characterised. The nature of the biofilm enhances the component bacterias' resistance to both the host's defence system and antimicrobials. If not removed regularly the biofilm undergoes maturation, resulting in dental caries, gingivitis, and periodontitis. The control of biofilm accumulation on teeth has been the cornerstone of periodontal disease prevention for decades. However, the widespread prevalence of gingivitis suggests the inefficiency of self-performed mechanical plaque control in preventing gingival inflammation. Studies indicate that effective antiseptic mouth-washes can provide significant gingivitis reduction beyond what can be accomplished with only brushing and flossing. Particularly, mouthrinses containing essential oils have well documented clinical antiplaque and antigingivitis effects. These mouthrinses have a positive track record of safety and their use does not increase the levels of resistant species. In summary, use of a well-established, essential oil mouthrinse can be recommended for daily use as an adjunct to mechanical methods of plaque control.}, } @article {pmid28480869, year = {2017}, author = {Zhang, X and Zhang, W and Liu, L and Yang, M and Huang, L and Chen, K and Wang, R and Yang, B and Zhang, D and Wang, J}, title = {Antibiotic-loaded MoS2 nanosheets to combat bacterial resistance via biofilm inhibition.}, journal = {Nanotechnology}, volume = {28}, number = {22}, pages = {225101}, doi = {10.1088/1361-6528/aa6c9b}, pmid = {28480869}, issn = {1361-6528}, abstract = {The emergence of antibiotic resistance has resulted in increasing difficulty in treating clinical infections associated with biofilm formation, one of the key processes in turn contributing to enhanced antibiotic resistance. With the rapid development of nanotechnology, a new way to overcome antibiotic resistance has opened up. Based on the many and diverse properties of MoS2 nanosheets that have attracted wide attention, in particular their antibacterial potential, herein, a novel antimicrobial agent to combat resistant gram-positive Staphylococcus aureus and gram-negative Salmonella was prepared using chitosan functionalized MoS2 nanosheets loading tetracycline hydrochloride drugs (abbreviated to CM-TH). The antibacterial and anti-biofilm activities of the CM-TH nanocomposites showed the synergetic effect that the combination of nanomaterials and antibiotics was more efficient than either working alone. In particularly, the minimum inhibitory concentration values generally decreased by a factor of dozens, suggesting that CM-TH may become a possible alternative to traditional antibiotics in disrupting biofilms and overcoming antibiotic resistance in treating medical diseases.}, } @article {pmid28480700, year = {2017}, author = {Zhang, P and Li, S and Chen, H and Wang, X and Liu, L and Lv, F and Wang, S}, title = {Biofilm Inhibition and Elimination Regulated by Cationic Conjugated Polymers.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {20}, pages = {16933-16938}, doi = {10.1021/acsami.7b05227}, pmid = {28480700}, issn = {1944-8252}, mesh = {*Biofilms ; Cations ; Plankton ; Polymers ; Staphylococcus aureus ; }, abstract = {In this work, we demonstrate that water-soluble conjugated polymers (PFP) have the ability to inhibit biofilm formation and eradicate mature established biofilm using reactive oxygen species (ROS) produced by PFP under white light irradiation. Upon addition of PFP to planktonic Staphylococcus aureus (S. aureus), electrostatic interactions bring cationic PFP to the surface of S. aureus, which possesses negative charges. As the amount of PFP coated on S. aureus becomes saturated, the interactions of bacteria to bacteria and bacteria to surface may be disrupted, resulting in reduced biofilm formation. After the biofilm matures, those PFP on the surface of the biofilm can generate ROS under white light irradiation, which has the ability to inactivate bacteria nearby. Once the biofilm is broken, PFP can penetrate throughthe biofilm and continuously generate ROS under irradiation, resulting in biofilm disruption. As a consequence, this makes conjugated polymers a very promising material for the disruption of biofilm in biomedical and industrial applications.}, } @article {pmid28480361, year = {2016}, author = {Avcioglu, NH and Sahal, G and Bilkay, IS}, title = {ANTIBIOFILM EFFECTS of Citrus limonum and Zingiber officinale Oils on BIOFILM FORMATION of Klebsiella ornithinolytica, Klebsiella oxytoca and Klebsiella terrigena SPECIES.}, journal = {African journal of traditional, complementary, and alternative medicines : AJTCAM}, volume = {13}, number = {6}, pages = {61-67}, pmid = {28480361}, issn = {2505-0044}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Citrus/*chemistry ; Ginger/*chemistry ; Klebsiella/*physiology ; Klebsiella Infections/drug therapy ; Oils, Volatile/*pharmacology ; }, abstract = {BACKGROUND: Microbial cells growing in biofilms, play a huge role in the spread of antimicrobial resistance. In this study, biofilm formation of Klebsiella strains belonging to 3 different Klebsiella species (K. ornithinolytica, K. oxytoca and K. terrigena), cooccurences' effect on biofilm formation amount and anti-biofilm effects of Citrus limon and Zingiber officinale essential oils on biofilm formations of highest biofilm forming K. ornithinolytica, K. oxytoca and K. terrigena strains were determined.

MATERIALS AND METHODS: Anti-biofilm effects of Citrus limon and Zingiber officinale essential oils on biofilm formations of highest biofilm forming K. ornithinolytica, K. oxytoca and K. terrigena strains were investigated.

RESULTS: 57% of K. ornithinolytica strains and 50% of K. oxytoca strains were found as Strong Biofilm Forming (SBF), there wasn't any SBF strain in K. terrigena species. In addition to this, clinical materials of urine and sperm were found as the most frequent clinical materials for strong biofilm forming K. ornithinolytica and K. oxytoca isolations respectively (63%; 100%) Secondly, all K. ornithinolytica strains isolated from surgical intensive care unit and all K. oxytoca strains isolated from service units of urology were found as SBF. Apart from these, although the amount of biofilm, formed by co-occurence of K. ornithinolytica - K. oxytoca and K. oxytoca - K. terrigena were more than the amount ofbiofilm formed by themselves separately, biofilm formation amount of co-occurrence of K. ornitholytica - K. terrigena strains was lower than biofilm formation amount of K. ornithinolytica but higher than biofilm formation amount of K. terrigena.

CONCLUSION: The antibiofilm effects of Citrus limonum and Zingiber officinale essential oils could be used against biofilm Klebsiella aquired infections.}, } @article {pmid28478657, year = {2017}, author = {Choi, HA and Cheong, DE and Lim, HD and Kim, WH and Ham, MH and Oh, MH and Wu, Y and Shin, HJ and Kim, GJ}, title = {Antimicrobial and Anti-Biofilm Activities of the Methanol Extracts of Medicinal Plants against Dental Pathogens Streptococcus mutans and Candida albicans.}, journal = {Journal of microbiology and biotechnology}, volume = {27}, number = {7}, pages = {1242-1248}, doi = {10.4014/jmb.1701.01026}, pmid = {28478657}, issn = {1738-8872}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/physiology ; Dental Caries/drug therapy ; Methanol ; Microbial Sensitivity Tests ; Mouth/microbiology ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Plants, Medicinal/chemistry ; Republic of Korea ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {Several medicinal plants are ethnomedically used in Korea as agents for treating infection, anti-inflammation, and pain relief. However, beyond typical inhibitory effects on cell growth, little is known about the potential anti-biofilm activity of these herbs, which may help to prevent cavities and maintain good oral health. This study aimed to investigate the antimicrobial and anti-biofilm activities of the methanol extracts of 37 Korean medicinal plants against dental pathogens Streptococcus mutans and Candida albicans, which synergize their virulence so as to induce the formation of plaque biofilms in the oral cavity. The antimicrobial activities were investigated by broth dilution and disk diffusion assay. The anti-biofilm and antioxidant activities were evaluated based on the inhibitory effect against glucosyltransferase (GTase) and the DPPH assay, respectively. Among 37 herbs, eight plant extracts presented growth and biofilm inhibitory activities against both etiologic bacteria. Among them, the methanol extracts (1.0 mg/ml) from Camellia japonica and Thuja orientalis significantly inhibited the growth of both bacteria by over 76% and over 83% in liquid media, respectively. Minimum inhibitory concentration (MIC) values of these methanol extracts were determined to be 0.5 mg/ml using a disk diffusion assay on solid agar media. Biofilm formation was inhibited by more than 92.4% and 98.0%, respectively, using the same concentration of each extract. The present results demonstrate that the medicinal plants C. japonica and T. orientalis are potentially useful as antimicrobial and anti-biofilm agents in preventing dental diseases.}, } @article {pmid28475673, year = {2017}, author = {Holt, JE and Houston, A and Adams, C and Edwards, S and Kjellerup, BV}, title = {Role of extracellular polymeric substances in polymicrobial biofilm infections of Staphylococcus epidermidis and Candida albicans modelled in the nematode Caenorhabditis elegans.}, journal = {Pathogens and disease}, volume = {75}, number = {5}, pages = {}, pmid = {28475673}, issn = {2049-632X}, support = {P40 OD010440/OD/NIH HHS/United States ; }, mesh = {Animals ; Bacterial Infections/complications/*microbiology ; Biofilms/*growth & development ; Biological Assay ; Caenorhabditis elegans ; Candida albicans/growth & development/metabolism/pathogenicity/*physiology ; Coinfection/*microbiology ; Disease Models, Animal ; Microbial Interactions ; Mycoses/complications/*microbiology ; Polymers/*metabolism ; Staphylococcus epidermidis/growth & development/metabolism/pathogenicity/*physiology ; Survival Analysis ; Virulence ; }, abstract = {Biofilms are formed by communities of microorganisms living in a self-produced extracellular polymeric matrix attached to a surface. When living in a biofilm microorganisms change phenotype and thus are less susceptible to antibiotic treatment and biofilm infections can become severe. The aim of this study was to determine if the presence of multikingdom microorganisms alters the virulence of a biofilm infection in a host organism. The coexistence of Candida albicans and Staphylococcus epidermidis in biofilm was examined in the nematode model Caenorhabditis elegans. It was evaluated if the hyphal form of C. albicans and extracellular polymeric substances (EPS) formed by S. epidermidis increases biofilm virulence. Survival assays were performed, where C. elegans nematodes were exposed to S. epidermidis and C. albicans. Single inoculation assays showed a decreased survival rate after 2 days following exposure, while dual inoculation assays showed that a clinical S. epidermidis strain together with C. albicans significantly increased the virulence and decreased nematode survival. EPS seem to interfere with the bacterial attachment to hyphae, since the EPS overproducing S. epidermidis strain was most virulent. The clinical S. epidermidis paired with C. albicans led to a severe infection in the nematodes resulting in reduced survival.}, } @article {pmid28473809, year = {2017}, author = {Popowska, M and Krawczyk-Balska, A and Ostrowski, R and Desvaux, M}, title = {InlL from Listeria monocytogenes Is Involved in Biofilm Formation and Adhesion to Mucin.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {660}, pmid = {28473809}, issn = {1664-302X}, abstract = {The bacterial etiological agent of listeriosis, Listeria monocytogenes, is an opportunistic intracellular foodborne pathogen. The infection cycle of L. monocytogenes is well-characterized and involves several key virulence factors, including internalins A and B. While 35 genes encoding internalins have been identified in L. monocytogenes, less than half of them have been characterized as yet. Focusing on lmo2026, it was shown this gene encodes a class I internalin, InlL, exhibiting domains potentially involved in adhesion. Following a functional genetic approach, InlL was demonstrated to be involved in initial bacterial adhesion as well as sessile development in L. monocytogenes. In addition, InlL enables binding to mucin of type 2, i.e., the main secreted mucin making up the mucus layer, rather than to surface-located mucin of type 1. InlL thus appears as a new molecular determinant contributing to the colonization ability of L. monocytogenes.}, } @article {pmid28470798, year = {2017}, author = {Parker, A and Cureoglu, S and De Lay, N and Majdalani, N and Gottesman, S}, title = {Alternative pathways for Escherichia coli biofilm formation revealed by sRNA overproduction.}, journal = {Molecular microbiology}, volume = {105}, number = {2}, pages = {309-325}, pmid = {28470798}, issn = {1365-2958}, support = {Z01 BC008714-30//Intramural NIH HHS/United States ; Z01 BC008714-31//Intramural NIH HHS/United States ; Z99 CA999999//Intramural NIH HHS/United States ; }, mesh = {Bacterial Outer Membrane Proteins/genetics/*metabolism ; Bacterial Proteins/genetics/metabolism ; Binding Sites ; Biofilms/*growth & development ; Escherichia coli/genetics ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/genetics ; Host Factor 1 Protein/metabolism ; RNA, Bacterial/metabolism ; RNA, Messenger/metabolism ; RNA, Small Untranslated/genetics/*metabolism ; Sigma Factor/genetics/metabolism ; Trans-Activators/genetics/metabolism ; }, abstract = {Small regulatory RNAs have major roles in many regulatory circuits in Escherichia coli and other bacteria, including the transition from planktonic to biofilm growth. We tested Hfq-dependent sRNAs in E. coli for their ability, when overproduced, to inhibit or stimulate biofilm formation, in two different growth media. We identify two mutually exclusive pathways for biofilm formation. In LB, PgaA, encoding an adhesion export protein, played a critical role; biofilm was independent of the general stress factor RpoS or CsgD, regulator of curli and other biofilm genes. The PgaA-dependent pathway was stimulated upon overproduction of DsrA, via negative regulation of H-NS, or of GadY, likely by titration of CsrA. In yeast extract casamino acids (YESCA) media, biofilm was dependent on RpoS and CsgD, but independent of PgaA; RpoS appears to indirectly negatively regulate the PgaA-dependent pathway in YESCA medium. Deletions of most sRNAs had very little effect on biofilm, although deletion of hfq, encoding an RNA chaperone, was defective in both LB and YESCA. Deletion of ArcZ, a small RNA activator of RpoS, decreased biofilm in YESCA; only a portion of this defect could be bypassed by overproduction of RpoS. Overall, sRNAs highlight different pathways to biofilm formation.}, } @article {pmid28470375, year = {2017}, author = {Yahya, MFZR and Alias, Z and Karsani, SA}, title = {Subtractive Protein Profiling of Salmonella typhimurium Biofilm Treated with DMSO.}, journal = {The protein journal}, volume = {36}, number = {4}, pages = {286-298}, pmid = {28470375}, issn = {1875-8355}, mesh = {Amino Acid Sequence ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Biological Assay ; Dimethyl Sulfoxide/*pharmacology ; Electrophoresis, Polyacrylamide Gel ; Flagella/drug effects/genetics/metabolism ; Gene Expression Profiling/methods ; Gene Expression Regulation, Bacterial/*drug effects ; Gene Ontology ; Gene Regulatory Networks/drug effects ; Glycolysis/drug effects/genetics ; Molecular Sequence Annotation ; Salmonella typhimurium/*drug effects/genetics/metabolism ; Tandem Mass Spectrometry ; }, abstract = {Salmonella typhimurium is an important biofilm-forming bacteria. It is known to be resistant to a wide range of antimicrobials. The present study was carried out to evaluate the effects of dimethyl sulfoxide (DMSO) against S. typhimurium biofilm and investigate whole-cell protein expression by biofilm cells following treatment with DMSO. Antibiofilm activities were assessed using pellicle assay, crystal violet assay, colony-forming unit counting and extracellular polymeric substance (EPS) matrix assay whilst differential protein expression was investigated using a combination of one dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, tandem mass spectrometry and bioinformatics. Treatment with 32% DMSO inhibited pellicle formation, biofilm viability, biofilm biomass and several important components of EPS matrix. Subtractive protein profiling identified two unique protein bands (25.4 and 51.2 kDa) which were present only in control biofilm and not in 32% DMSO-treated biofilm. In turn, 29 and 46 proteins were successfully identified from the protein bands of 25.4 and 51.2 kDa respectively. Protein interaction network analysis identified several biological pathways to be affected, including glycolysis, PhoP-PhoQ phosphorelay signalling and flagellar biosynthesis. The present study suggests that DMSO may inhibit multiple biological pathways to control biofilm formation.}, } @article {pmid28470309, year = {2017}, author = {Neto, CC and Penndorf, KA and Feldman, M and Meron-Sudai, S and Zakay-Rones, Z and Steinberg, D and Fridman, M and Kashman, Y and Ginsburg, I and Ofek, I and Weiss, EI}, title = {Characterization of non-dialyzable constituents from cranberry juice that inhibit adhesion, co-aggregation and biofilm formation by oral bacteria.}, journal = {Food & function}, volume = {8}, number = {5}, pages = {1955-1965}, doi = {10.1039/c7fo00109f}, pmid = {28470309}, issn = {2042-650X}, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Fruit and Vegetable Juices/analysis ; Fusobacterium nucleatum/*drug effects/physiology ; Humans ; Mouth/*microbiology ; Plant Extracts/chemistry/*pharmacology ; Porphyromonas gingivalis/*drug effects/physiology ; Streptococcus/*drug effects/physiology ; Vaccinium macrocarpon/*chemistry ; }, abstract = {An extract prepared from cranberry juice by dialysis known as nondialyzable material (NDM) has been shown previously to possess anti-adhesion activity toward microbial species including oral bacteria, uropathogenic Escherichia coli and Helicobacter pylori. Bioassay-guided fractionation of cranberry NDM was therefore undertaken to identify the anti-adhesive constituents. An aqueous acetone-soluble fraction (NDMac) obtained from Sephadex LH-20 inhibited adhesion-linked activities by oral bacteria, including co-aggregation of oral bacteria Fusobacterium nucleatum with Streptococcus sanguinis or Porphyromonas gingivalis, and biofilm formation by Streptococcus mutans. Analysis of NDMac and subsequent subfractions by MALDI-TOF MS and [1]H NMR revealed the presence of A-type proanthocyanidin oligomers (PACs) of 3-6 degrees of polymerization composed of (epi)catechin units, with some (epi)gallocatechin and anthocyanin units also present, as well as quercetin derivatives. Subfractions containing putative xyloglucans in addition to the mixed polyphenols also inhibit biofilm formation by S. mutans (MIC = 125-250 μg mL[-1]). These studies suggest that the anti-adhesion activities of cranberry NDM on oral bacteria may arise from a combination of mixed polyphenol and non-polyphenol constituents.}, } @article {pmid28470089, year = {2017}, author = {El Hag, M and Feng, Z and Su, Y and Wang, X and Yassin, A and Chen, S and Peng, D and Liu, X}, title = {Contribution of the csgA and bcsA genes to Salmonella enterica serovar Pullorum biofilm formation and virulence.}, journal = {Avian pathology : journal of the W.V.P.A}, volume = {46}, number = {5}, pages = {541-547}, doi = {10.1080/03079457.2017.1324198}, pmid = {28470089}, issn = {1465-3338}, mesh = {Animals ; Bacterial Adhesion/physiology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Chickens ; Gene Expression Regulation, Bacterial/physiology ; HeLa Cells ; Humans ; Lipopolysaccharides ; Macrophages ; Poultry Diseases/microbiology/pathology ; Salmonella Infections, Animal/microbiology/pathology ; Salmonella enterica/*pathogenicity/*physiology ; Specific Pathogen-Free Organisms ; Virulence ; }, abstract = {Salmonella biofilm formation is important to environmental stress resistance and virulence. However, the roles of the csgA and bcsA genes, which affect curli protein and cellulose production, respectively, in Salmonella enterica serovar Pullorum, are unknown. Here we constructed deletions in the csgA and bcsA genes in S. enterica serovar Pullorum strain S6702 and evaluated several aspects of biofilm formation and virulence. ΔcsgA showed decreased production of curli fimbriae, while ΔbcsA had reduced cellulose production. Both mutants had a reduced ability to form biofilms. ΔcsgA was reduced in adhesion and invasion to HeLa cells and exhibited decreased intracellular proliferation in HD11 macrophages. ΔbcsA exhibited increased proliferation in HD11 cells and replicated better in chicken spleens, as compared to the wild-type strain. ΔcsgA virulence was attenuated in assays involving oral challenge of one-day-old chickens.}, } @article {pmid28469603, year = {2017}, author = {Gao, Y and Wu, D and Wang, L and Lin, C and Ma, C and Xi, X and Zhou, M and Duan, J and Bininda-Emonds, ORP and Chen, T and Shaw, C}, title = {Targeted Modification of a Novel Amphibian Antimicrobial Peptide from Phyllomedusa tarsius to Enhance Its Activity against MRSA and Microbial Biofilm.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {628}, pmid = {28469603}, issn = {1664-302X}, abstract = {Antimicrobial peptides (AMPs) in the skin secretions of amphibians are fundamental components of a unique defense system that has evolved to protect these hosts from microbial invasion. Medusins constitute a recently-discovered AMP family from phyllomedusine leaf frog skin and exhibit highly-conserved structural characteristics. Here, we report a novel medusin, medusin-PT, from the skin secretion of the Tarsier Leaf Frog, Phyllomedusa tarsius. The mature peptide was initially identified from its cloned biosynthetic precursor-encoding cDNA as obtained by the rapid amplification of cDNA ends (RACE) method. Reverse-phase HPLC and tandem mass spectrometry confirmed both the presence of medusin-PT in the skin secretion and its primary structure. In a range of bioassays, medusin-PT exhibited antimicrobial activity against only the Gram-positive bacterium Staphylococcus aureus at 64 μg/ml. However, after directed changes to enhance the cationicity and amphipathicity of the peptide structure, three analog showed more potent antimicrobial activity against several additional bacteria including the antibiotic-resistant bacterium MRSA. In addition, these analog exhibited activity against microbial biofilm (minimum biofilm inhibitory and eradication concentrations of 32 μg/ml and over 64 μg/ml, respectively). These data provide evidence that medusins might be promising candidates as novel antibiotic leads and that the targeted modification of a natural AMP can both improve its efficacy so as to provide new insights into antibiotic design and development.}, } @article {pmid28468829, year = {2017}, author = {Kuttel, MM and Cescutti, P and Distefano, M and Rizzo, R}, title = {Fluorescence and NMR spectroscopy together with molecular simulations reveal amphiphilic characteristics of a Burkholderia biofilm exopolysaccharide.}, journal = {The Journal of biological chemistry}, volume = {292}, number = {26}, pages = {11034-11042}, pmid = {28468829}, issn = {1083-351X}, mesh = {Biofilms/*growth & development ; Burkholderia/chemistry/*physiology ; Magnetic Resonance Spectroscopy/methods ; Polysaccharides, Bacterial/chemistry/*metabolism ; Spectrometry, Fluorescence/methods ; }, abstract = {Biofilms are a collective mode of bacterial life in which a self-produced matrix confines cells in close proximity to each other. Biofilms confer many advantages, including protection from chemicals (including antibiotics), entrapment of useful extracellular enzymes and nutrients, as well as opportunities for efficient recycling of molecules from dead cells. Biofilm matrices are aqueous gel-like structures composed of polysaccharides, proteins, and DNA stabilized by intermolecular interactions that may include non-polar connections. Recently, polysaccharides extracted from biofilms produced by species of the Burkholderia cepacia complex were shown to possess clusters of rhamnose, a 6-deoxy sugar with non-polar characteristics. Molecular dynamics simulations are well suited to characterizing the structure and dynamics of polysaccharides, but only relatively few such studies exist of their interaction with non-polar molecules. Here we report an investigation into the hydrophobic properties of the exopolysaccharide produced by Burkholderia multivorans strain C1576. Fluorescence experiments with two hydrophobic fluorescent probes established that this polysaccharide complexes hydrophobic species, and NMR experiments confirmed these interactions. Molecular simulations to model the hydrodynamics of the polysaccharide and the interaction with guest species revealed a very flexible, amphiphilic carbohydrate chain that has frequent dynamic interactions with apolar molecules; both hexane and a long-chain fatty acid belonging to the quorum-sensing system of B. multivorans were tested. A possible role of the non-polar domains of the exopolysaccharide in facilitating the diffusion of aliphatic species toward specific targets within the biofilm aqueous matrix is proposed.}, } @article {pmid28468513, year = {2017}, author = {Al Ashhab, A and Sweity, A and Bayramoglu, B and Herzberg, M and Gillor, O}, title = {Biofouling of reverse osmosis membranes: effects of cleaning on biofilm microbial communities, membrane performance, and adherence of extracellular polymeric substances.}, journal = {Biofouling}, volume = {33}, number = {5}, pages = {397-409}, doi = {10.1080/08927014.2017.1318382}, pmid = {28468513}, issn = {1029-2454}, mesh = {Ascomycota/drug effects/growth & development/physiology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Biofouling/*prevention & control ; Detergents/*pharmacology ; Filtration ; *Membranes, Artificial ; Osmosis ; Polymers/chemistry ; Proteobacteria/*drug effects/growth & development ; Water Purification/methods ; }, abstract = {Laboratory-scale reverse osmosis (RO) flat-sheet systems were used with two parallel flow cells, one treated with cleaning agents and a control (ie undisturbed). The cleaning efforts increased the affinity of extracellular polymeric substances (EPS) to the RO membrane and altered the biofilm surface structure. Analysis of the membrane biofilm community composition revealed the dominance of Proteobacteria. However, within the phylum Proteobacteria, γ-Proteobacteria dominated the cleaned membrane biofilm, while β-Proteobacteria dominated the control biofilm. The composition of the fungal phyla was also altered by cleaning, with enhancement of Ascomycota and suppression of Basidiomycota. The results suggest that repeated cleaning cycles select for microbial groups that strongly attach to the RO membrane surface by producing rigid and adhesive EPS that hampers membrane performance.}, } @article {pmid28466356, year = {2017}, author = {Jensen, RG and Johansen, HK and Bjarnsholt, T and Eickhardt-Sørensen, SR and Homøe, P}, title = {Recurrent otorrhea in chronic suppurative otitis media: is biofilm the missing link?.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {274}, number = {7}, pages = {2741-2747}, pmid = {28466356}, issn = {1434-4726}, mesh = {Administration, Topical ; Adolescent ; Adult ; Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Child ; Child, Preschool ; Chronic Disease ; Ciprofloxacin/therapeutic use ; Combined Modality Therapy ; Ear, Middle/*microbiology ; Female ; Greenland ; Humans ; Infant ; Male ; Otitis Media, Suppurative/drug therapy/*microbiology/therapy ; Prospective Studies ; Recurrence ; Therapeutic Irrigation ; Young Adult ; }, abstract = {Dispersal of bacteria from a biofilm in the middle ear, serving as a bacterial reservoir, could explain the recurrent and chronic nature of chronic suppurative otitis media (CSOM). The objective of this study is to investigate if the same strains of bacteria could be detected in repeated episodes of otorrhea in CSOM. In a prospective case series at a primary healthcare clinic in Nuuk, Greenland, patients with more than 14 days of otorrhea were included consecutively. Samples for culturing and biofilm analysis were taken at enrollment and at any subsequent episode with otorrhea. Participants were treated with daily saline irrigation and Ciprofloxacin eardrops for 7-14 days. Biofilm was identified in otorrhea in 81% (17/21) of participants at enrollment. Multispecies infections dominated with Non-typeable Haemophilus Influenzae (NTHI), Staphyloccocus aureus, and anaerobes being the most frequent pathogens. After the initial treatment, 19 (90%) had dry ears. Median observation period was 140 days (range 14-280) where 13 participants had one or more recurrences. Median time to first recurrence was 60 days (range 14-197). Among the 13 with recurrence, three individuals had the same genotype of bacteria at a subsequent episode. Another two had the same phenotype (NTHI). The remaining eight had new multispecies infections. We confirmed a high rate of biofilm in CSOM. However, the clinical implication might be of minor importance when treating with irrigation and antibiotic eardrops, as recurrent episodes of otorrhea were dominated by new pathogens in each episode.}, } @article {pmid28465599, year = {2017}, author = {Fang, H and Chen, Y and Huang, L and He, G}, title = {Analysis of biofilm bacterial communities under different shear stresses using size-fractionated sediment.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {1299}, pmid = {28465599}, issn = {2045-2322}, mesh = {Bacteroidetes/*genetics ; Biodiversity ; *Biofilms ; Ecosystem ; Geologic Sediments/microbiology ; Lakes/microbiology ; Proteobacteria/*genetics ; RNA, Ribosomal, 16S/*genetics ; Stress, Mechanical ; }, abstract = {Microorganisms are ubiquitous in aqueous environments and are crucial for biogeochemical processes, but their community structures and functions remain poorly understood. In this paper, a rotating reactor was designed to study the effects of substrata and flow conditions on sediment bacterial communities using 16S rRNA gene sequencing, assaying three groups of size-fractionated sediments and three different levels of applied shear stress. Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla of the microbial communities, with more anaerobic bacteria and opportunistic pathogens being detected under static water conditions, while more aerobic bacteria were detected under dynamic water flow conditions. Most of the top 10 genera were present in all the samples; however, there were significant differences in the species abundance. Paludibacter and Comamonadaceae_unclassified were the most abundant genera under static and dynamic conditions, respectively. Under static water conditions, the medium-grained sediment had the highest microbial diversity, followed by the fine and coarse sediments. Under dynamic water flow conditions, a higher flow velocity corresponded to a greater microbial diversity. Overall, there was no significant difference in the community richness or diversity between the static and dynamic water flow conditions. This study is beneficial for further understanding the heterogeneities of microbial communities in natural aquatic ecosystems.}, } @article {pmid28464222, year = {2017}, author = {Baeten, JE and van Loosdrecht, MCM and Volcke, EIP}, title = {Improving the accuracy of granular sludge and biofilm reactor simulations in Aquasim through artificial diffusion.}, journal = {Biotechnology and bioengineering}, volume = {114}, number = {9}, pages = {2131-2136}, doi = {10.1002/bit.26323}, pmid = {28464222}, issn = {1097-0290}, mesh = {*Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Computer Simulation ; Diffusion ; *Models, Biological ; Models, Chemical ; Reproducibility of Results ; Sensitivity and Specificity ; Sewage/chemistry/*microbiology ; *Software ; }, abstract = {Aquasim is public-domain and user-friendly software that is widely used for biofilm modeling. The program uses built-in process unit blocks, such as biofilm and mixed compartments. In the literature, often several of these compartments are linked with artificial advective flows to represent a single physical well-mixed system, such as a granular sludge reactor. This work shows that caution should be exercised with this popular approach because numerical errors occur when too high artificial advective flows are used. These errors could stay unnoticed if mass-balances of the simulation results are not checked. A solution to this problem is proposed in this work. A new method based on diffusive links between compartments instead of advective links leads to more reliable and faster simulations and is much easier to implement. Biotechnol. Bioeng. 2017;114: 2131-2136. © 2017 Wiley Periodicals, Inc.}, } @article {pmid28463986, year = {2017}, author = {Jwanoswki, K and Wells, C and Bruce, T and Rutt, J and Banks, T and McNealy, TL}, title = {The Legionella pneumophila GIG operon responds to gold and copper in planktonic and biofilm cultures.}, journal = {PloS one}, volume = {12}, number = {5}, pages = {e0174245}, pmid = {28463986}, issn = {1932-6203}, mesh = {Biofilms/*drug effects/growth & development ; Copper/*pharmacology ; Copper Sulfate/*pharmacology ; Dose-Response Relationship, Drug ; Gold Compounds/*pharmacology ; Legionella pneumophila/*drug effects/growth & development ; Operon/*drug effects ; Silver Nitrate/pharmacology ; Temperature ; }, abstract = {Legionella pneumophila contaminates man-made water systems and creates numerous exposure risks for Legionnaires' Disease. Because copper/silver ionization is commonly used to control L. pneumophila, its mechanisms of metal response and detoxification are of significant interest. Here we describe an L. pneumophila operon with significant similarity to the GIG operon of Cupriavidus metallidurans. The Legionella GIG operon is present in a subset of strains and has been acquired as part of the ICE-βox 65-kB integrative conjugative element. We assessed GIG promoter activity following exposure of L. pneumophila to multiple concentrations of HAuCl4, CuSO4 and AgNO3. At 37°C, control stationary phase cultures exhibited GIG promoter activity. This activity increased significantly in response to 20 and 50uM HAuCl4 and CuSO4 but not in response to AgNO3. Conversely, at 26°C, cultures exhibited decreased promoter response to copper. GIG promoter activity was also induced by HAuCl4 or CuSO4 during early biofilm establishment at both temperatures. When an L. pneumophila GIG promoter construct was transformed into E. coli DH5α, cultures showed baseline expression levels that did not increase following metal addition. Analysis of L. pneumophila transcriptional regulatory mutants suggested that GIG up-regulation in the presence of metal ions may be influenced by the stationary phase sigma factor, RpoS.}, } @article {pmid28463781, year = {2017}, author = {Vollmerhausen, TL and Conneely, A and Bennett, C and Wagner, VE and Victor, JC and O'Byrne, CP}, title = {Visible and UVA light as a potential means of preventing Escherichia coli biofilm formation in urine and on materials used in urethral catheters.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {170}, number = {}, pages = {295-303}, doi = {10.1016/j.jphotobiol.2017.04.018}, pmid = {28463781}, issn = {1873-2682}, mesh = {Biofilms/*radiation effects ; Escherichia coli/*physiology ; Humans ; *Light ; Mucins/urine ; Reactive Oxygen Species/metabolism ; Silicones/chemistry ; *Ultraviolet Rays ; Urinary Catheters/microbiology ; }, abstract = {Catheter-associated urinary tract infections are the most common hospital-acquired infection, for which Escherichia coli is the leading cause. This study investigated the efficacy of 385nm and 420nm light for inactivation of E. coli attached to the silicone matrix of a urinary catheter. Using urine mucin media, inactivation of planktonic bacteria and biofilm formation was monitored using silicone coupons. Continuous irradiance with both 385nm and 420nm wavelengths with starting cell density population 10[3]CFU ml[-1] reduced planktonic suspensions of E. coli to below the detection level after 2h and 6h, respectively. Bacterial attachment to silicone was successfully prevented during the same treatment. Inactivation by 385nm and 420nm was found to be dependent on media, cell density and oxygen, with less inhibition on planktonic suspensions when higher starting cell densities were used. In contrast to planktonic suspensions in PBS, continuous irradiance of pre-established biofilms showed a greater reduction in survival compared to urine mucin media after 24h. Enhanced inhibition for 385nm and 420nm light in urine mucin media was associated with increased production of reactive oxygen species. These findings suggest 385nm and 420nm light as a promising antimicrobial technology for the prevention of biofilm formation on urethral catheters.}, } @article {pmid28463771, year = {2017}, author = {Wu, Y and Li, Y and Ontiveros-Valencia, A and Ordaz-Díaz, L and Liu, J and Zhou, C and Rittmann, BE}, title = {Enhancing denitrification using a novel in situ membrane biofilm reactor (isMBfR).}, journal = {Water research}, volume = {119}, number = {}, pages = {234-241}, doi = {10.1016/j.watres.2017.04.054}, pmid = {28463771}, issn = {1879-2448}, mesh = {*Biofilms ; Bioreactors ; *Denitrification ; Hydrogen ; *Nitrates ; Water Purification ; }, abstract = {The insufficient supply of electron donor in surface water contaminated with nitrate leads to its incomplete reduction in natural or constructed wetlands. Although the addition of organic matter (represented as chemical oxygen demand, COD) can stimulate N removal by denitrification, direct supplementation of COD creates unacceptable risks to effluent quality. An alternative for stimulating denitrification is supplying hydrogen gas (H2) as an inorganic electron donor. We evaluate an innovative means to do H2-based denitrification of surface waters in a wetland setting: the in-situ membrane biofilm reactor (isMBfR), in which H2 is delivered to a biofilm of denitrifying bacteria on demand based on the presence of nitrate. We carried out a proof-of-concept study in which an upper "photo zone" and a lower "MBfR root zone" were combined to remove nitrate and COD from simulated surface water. Employing mass-balances for H2, COD, nitrate, and oxygen, we documented nearly complete removals of nitrate and COD, except when the H2 supply was intentionally shut off. All nitrate removal was accomplished in the "MBfR root zone," where H2 delivery supplemented the COD supply (as needed) and provided the large majority of electron equivalents to reduce nitrate to N2.}, } @article {pmid28463724, year = {2017}, author = {Li, J and Feng, J and Ma, L and de la Fuente Núñez, C and Gölz, G and Lu, X}, title = {Effects of meat juice on biofilm formation of Campylobacter and Salmonella.}, journal = {International journal of food microbiology}, volume = {253}, number = {}, pages = {20-28}, doi = {10.1016/j.ijfoodmicro.2017.04.013}, pmid = {28463724}, issn = {1879-3460}, mesh = {Animals ; Bacterial Load ; Biofilms/*growth & development ; Campylobacter/*growth & development/isolation & purification ; Chickens/microbiology ; Food Handling/methods ; Foodborne Diseases/microbiology ; Humans ; Meat Products/*microbiology ; Microfluidic Analytical Techniques ; Raw Foods/*microbiology ; Red Meat/*microbiology ; Salmonella/*growth & development/isolation & purification ; Swine/microbiology ; Tissue Extracts/pharmacology ; }, abstract = {Campylobacter and Salmonella are leading causes of foodborne illnesses worldwide, vastly harboured by raw meat as their common food reservoir. Both microbes are prevalent in meat processing environments in the form of biofilms that contribute to cross-contamination and foodborne infection. This study applied raw meat juice (chicken juice and pork juice) as a minimally processed food model to study its effects on bacterial biofilm formation. Meat juice was collected during the freeze-thaw process of raw meat and sterilized by filtration. In 96-well polystyrene plates and glass chambers, supplementation of over 25% meat juice (v/v) in laboratory media led to an increase in biofilm formation of Campylobacter and Salmonella. During the initial attachment stage of biofilm development, more bacterial cells were present on surfaces treated with meat juice residues compared to control surfaces. Meat juice particulates on abiotic surfaces facilitated biofilm formation of Campylobacter and Salmonella under both static and flow conditions, with the latter being assessed using a microfluidic platform. Further, the deficiency in biofilm formation of selected Campylobacter and Salmonella mutant strains was restored in the presence of meat juice particulates. These results suggested that meat juice residues on the abiotic surfaces might act as a surface conditioner to support initial attachment and biofilm formation of Campylobacter and Salmonella. This study sheds light on a possible survival mechanism of Campylobacter and Salmonella in meat processing environments, and indicates that thorough cleaning of meat residues during meat production and handling is critical to reduce the bacterial load of Campylobacter and Salmonella.}, } @article {pmid28463662, year = {2017}, author = {Brady, AJ and Laverty, G and Gilpin, DF and Kearney, P and Tunney, M}, title = {Antibiotic susceptibility of planktonic- and biofilm-grown staphylococci isolated from implant-associated infections: should MBEC and nature of biofilm formation replace MIC?.}, journal = {Journal of medical microbiology}, volume = {66}, number = {4}, pages = {461-469}, doi = {10.1099/jmm.0.000466}, pmid = {28463662}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biocompatible Materials ; Biofilms/drug effects/*growth & development ; Endopeptidase K/pharmacology ; Microbial Sensitivity Tests ; Periodic Acid/pharmacology ; Prostheses and Implants/*microbiology ; Staphylococcal Infections/drug therapy/microbiology ; Staphylococcus/*drug effects/*isolation & purification ; }, abstract = {PURPOSE: The purpose of this study was to develop an alternative, more clinically relevant approach to susceptibility reporting for implant-associated infections. Using 20 staphylococcal isolates, isolated from clinical implant infections, the majority (85 %) demonstrated biofilm-forming capabilities. A significantly increased minimum biofilm eradication concentration (MBEC) compared to minimum inhibitory concentration (MIC) breakpoint was obtained, with MBEC values greater than 256 µg ml-1 for the majority of bacteria. Such a vast increase was also demonstrated for isolates defined as negligible biofilm formers via crystal violet staining, likely due to the high protein content of biofilms, as confirmed by proteinase-K treatment.

METHODOLOGY: This study employed a variety of techniques to assess MIC and MBEC of the isolates tested. In addition, the nature of bacterial biofilm across a range of clinical isolates was investigated using crystal violet staining, sodium metaperiodate and proteinase-K treatment, and PCR analysis.Results/Key findings. Infection of medical implants is associated with increased rates of infection and increased bacterial tolerance to antibiotic strategies. Clinical significance is due to the presence of pathogens attached to biomaterial surfaces enclosed in an extracellular polymeric matrix termed the biofilm. This article highlights the importance of defining the clinical susceptibility of implant-associated infections in vitro using methods that are relevant to the biofilm phenotype in vivo, and highlights how current planktonic-based antimicrobial susceptibility tests are often misleading.

CONCLUSION: The use of biofilm-relevant susceptibility tests would improve patient outcomes by enabling correct antimicrobial regimens to be rapidly identified, reducing treatment failure and halting the spread of antimicrobial-resistant strains.}, } @article {pmid28462927, year = {2017}, author = {Martin, M and Dragoš, A and Hölscher, T and Maróti, G and Bálint, B and Westermann, M and Kovács, ÁT}, title = {De novo evolved interference competition promotes the spread of biofilm defectors.}, journal = {Nature communications}, volume = {8}, number = {}, pages = {15127}, pmid = {28462927}, issn = {2041-1723}, mesh = {Bacillus Phages/*genetics ; Bacillus subtilis/genetics/growth & development/*metabolism/virology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression ; *Genome, Bacterial ; Lysogeny ; Microbial Interactions/*genetics ; Polymorphism, Single Nucleotide ; Polysaccharides, Bacterial/*biosynthesis/genetics ; Prophages/genetics ; }, abstract = {Biofilms are social entities where bacteria live in tightly packed agglomerations, surrounded by self-secreted exopolymers. Since production of exopolymers is costly and potentially exploitable by non-producers, mechanisms that prevent invasion of non-producing mutants are hypothesized. Here we study long-term dynamics and evolution in Bacillus subtilis biofilm populations consisting of wild-type (WT) matrix producers and mutant non-producers. We show that non-producers initially fail to incorporate into biofilms formed by the WT cells, resulting in 100-fold lower final frequency compared to the WT. However, this is modulated in a long-term scenario, as non-producers evolve the ability to better incorporate into biofilms, thereby slightly decreasing the productivity of the whole population. Detailed molecular analysis reveals that the unexpected shift in the initially stable biofilm is coupled with newly evolved phage-mediated interference competition. Our work therefore demonstrates how collective behaviour can be disrupted as a result of rapid adaptation through mobile genetic elements.}, } @article {pmid28461449, year = {2017}, author = {Stubbendieck, RM and Straight, PD}, title = {Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology.}, journal = {Journal of bacteriology}, volume = {199}, number = {18}, pages = {}, pmid = {28461449}, issn = {1098-5530}, mesh = {ATP-Binding Cassette Transporters/metabolism ; Anti-Bacterial Agents/*metabolism ; *Antibiosis ; Artificial Gene Fusion ; Bacillus subtilis/drug effects/*physiology ; Biofilms/*growth & development ; DNA Transposable Elements ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; *Microbial Viability ; Mutagenesis, Insertional ; Mutation ; Signal Transduction ; Streptomyces/metabolism/*physiology ; }, abstract = {Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilisIMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.}, } @article {pmid28461320, year = {2017}, author = {Tan, JH and Vidaillac, C and Yam, JKH and Chua, SL and Givskov, M and Yang, L}, title = {In Vitro and In Vivo Efficacy of an LpxC Inhibitor, CHIR-090, Alone or Combined with Colistin against Pseudomonas aeruginosa Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {7}, pages = {}, pmid = {28461320}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Biofilms/*drug effects ; Colistin/*pharmacology/therapeutic use ; Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Female ; Hydroxamic Acids/*pharmacology/therapeutic use ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects/pathogenicity ; Threonine/*analogs & derivatives/pharmacology/therapeutic use ; }, abstract = {With the rapid spread of antimicrobial resistance in Gram-negative pathogens, biofilm-associated infections are increasingly harder to treat and combination therapy with colistin has become one of the most efficient therapeutic strategies. Our study aimed to evaluate the potential for the synergy of colistin combined with CHIR-090, a potent LpxC inhibitor, against in vitro and in vivoPseudomonas aeruginosa biofilms. Four P. aeruginosa isolates with various colistin susceptibilities were chosen for evaluation. The tested isolates of P. aeruginosa exhibited MIC values ranging from 1 to 64 and 0.0625 to 0.5 μg/ml for colistin and CHIR-090, respectively. Against 24-h static biofilms, minimum biofilm eradication concentration values ranged from 256 to 512 and 8 to >128 μg/ml for colistin and CHIR-090, respectively. Interestingly, subinhibitory concentrations of CHIR-090 contributed to the eradication of subpopulations of P. aeruginosa with the highest colistin MIC values. The combination of colistin and CHIR-090 at subinhibitory concentrations demonstrated synergistic activity both in vivo and in vitro and prevented the formation of colistin-tolerant subpopulations in in vitro biofilms. In summary, our study highlights the in vivo and in vitro synergistic activity of the colistin and CHIR-090 combination against both colistin-susceptible and -nonsusceptible P. aeruginosa biofilms. Further studies are warranted to investigate the clinical relevance of the combination of these two antimicrobials and outline the underlying mechanism for their synergistic action.}, } @article {pmid28461319, year = {2017}, author = {Schuch, R and Khan, BK and Raz, A and Rotolo, JA and Wittekind, M}, title = {Bacteriophage Lysin CF-301, a Potent Antistaphylococcal Biofilm Agent.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {7}, pages = {}, pmid = {28461319}, issn = {1098-6596}, support = {R01 AI011822/AI/NIAID NIH HHS/United States ; R37 AI011822/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriophages/*chemistry ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Staphylococcus/drug effects ; Staphylococcus aureus/drug effects ; }, abstract = {Biofilms pose a unique therapeutic challenge because of the antibiotic tolerance of constituent bacteria. Treatments for biofilm-based infections represent a major unmet medical need, requiring novel agents to eradicate mature biofilms. Our objective was to evaluate bacteriophage lysin CF-301 as a new agent to target Staphylococcus aureus biofilms. We used minimum biofilm-eradicating concentration (MBEC) assays on 95 S. aureus strains to obtain a 90% MBEC (MBEC90) value of ≤0.25 μg/ml for CF-301. Mature biofilms of coagulase-negative staphylococci, Streptococcus pyogenes, and Streptococcus agalactiae were also sensitive to disruption, with MBEC90 values ranging from 0.25 to 8 μg/ml. The potency of CF-301 was demonstrated against S. aureus biofilms formed on polystyrene, glass, surgical mesh, and catheters. In catheters, CF-301 removed all biofilm within 1 h and killed all released bacteria by 6 h. Mixed-species biofilms, formed by S. aureus and Staphylococcus epidermidis on several surfaces, were removed by CF-301, as were S. aureus biofilms either enriched for small-colony variants (SCVs) or grown in human synovial fluid. The antibacterial activity of CF-301 was further demonstrated against S. aureus persister cells in exponential-phase and stationary-phase populations. Finally, the antibiofilm activity of CF-301 was greatly improved in combinations with the cell wall hydrolase lysostaphin when tested against a range of S. aureus strains. In all, the data show that CF-301 is highly effective at disrupting biofilms and killing biofilm bacteria, and, as such, it may be an efficient new agent for treating staphylococcal infections with a biofilm component.}, } @article {pmid28461311, year = {2017}, author = {Torres, BGS and Helfer, VE and Bernardes, PM and Macedo, AJ and Nielsen, EI and Friberg, LE and Dalla Costa, T}, title = {Population Pharmacokinetic Modeling as a Tool To Characterize the Decrease in Ciprofloxacin Free Interstitial Levels Caused by Pseudomonas aeruginosa Biofilm Lung Infection in Wistar Rats.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {7}, pages = {}, pmid = {28461311}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacokinetics/*therapeutic use ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacokinetics/*therapeutic use ; Male ; Microbial Sensitivity Tests ; Microdialysis ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/*pathogenicity ; Rats ; Rats, Wistar ; }, abstract = {Biofilm formation plays an important role in the persistence of pulmonary infections, for example, in cystic fibrosis patients. So far, little is known about the antimicrobial lung disposition in biofilm-associated pneumonia. This study aimed to evaluate, by microdialysis, ciprofloxacin (CIP) penetration into the lungs of healthy and Pseudomonas aeruginosa biofilm-infected rats and to develop a comprehensive model to describe the CIP disposition under both conditions. P. aeruginosa was immobilized into alginate beads and intratracheally inoculated 14 days before CIP administration (20 mg/kg of body weight). Plasma and microdialysate were sampled from different animal groups, and the observations were evaluated by noncompartmental analysis (NCA) and population pharmacokinetic (popPK) analysis. The final model that successfully described all data consisted of an arterial and a venous central compartment and two peripheral distribution compartments, and the disposition in the lung was modeled as a two-compartment model structure linked to the venous compartment. Plasma clearance was approximately 32% lower in infected animals, leading to a significantly higher level of plasma CIP exposure (area under the concentration-time curve from time zero to infinity, 27.3 ± 12.1 μg · h/ml and 13.3 ± 3.5 μg · h/ml in infected and healthy rats, respectively). Despite the plasma exposure, infected animals showed a four times lower tissue concentration/plasma concentration ratio (lung penetration factor = 0.44 and 1.69 in infected and healthy rats, respectively), and lung clearance (CLlung) was added to the model for these animals (CLlung = 0.643 liters/h/kg) to explain the lower tissue concentrations. Our results indicate that P. aeruginosa biofilm infection reduces the CIP free interstitial lung concentrations and increases plasma exposure, suggesting that plasma concentrations alone are not a good surrogate of lung concentrations.}, } @article {pmid28460269, year = {2017}, author = {Endersen, L and Buttimer, C and Nevin, E and Coffey, A and Neve, H and Oliveira, H and Lavigne, R and O'Mahony, J}, title = {Investigating the biocontrol and anti-biofilm potential of a three phage cocktail against Cronobacter sakazakii in different brands of infant formula.}, journal = {International journal of food microbiology}, volume = {253}, number = {}, pages = {1-11}, doi = {10.1016/j.ijfoodmicro.2017.04.009}, pmid = {28460269}, issn = {1879-3460}, mesh = {Bacteriophages/genetics/*growth & development/isolation & purification ; Biofilms/*growth & development ; Biological Control Agents/*pharmacology ; Cronobacter sakazakii/*virology ; Food Contamination/prevention & control ; Food Microbiology ; Host Specificity ; Humans ; Infant ; Infant Formula/*microbiology ; Microbial Sensitivity Tests ; }, abstract = {In recent years, the microbiological safety of powdered infant formula has gained increasing attention due to the identification of contaminating C. sakazakii and its epidemiological link with life-threatening neonatal infections. Current intervention strategies have fallen short of ensuring the production of infant formula that is free from C. sakazakii. In this study, we describe the isolation and characterisation of three bacteriophages (phages) and their application as a phage cocktail to inhibit the growth of C. sakazakii in different brands of infant formula, while also assessing the phages ability to prevent biofilm formation. All three phages, isolated from slurry, possess a relatively broad host range, verified by their ability to infect across genera and species. When all three phages were combined and used as part of a phage cocktail, 73% coverage was obtained across all Cronobacter strains tested. Optimum thermo-tolerance and pH stability were determined between 4°C-37°C, and pH6-8, respectively, well within the normal range of application of infant formula. Genome sequencing and analysis revealed all the phages to be free from lysogenic properties, a trait which renders each favourable for phage therapy applications. As such, the combined-phage preparation (3×10[8]pfu/mL) was found to possess a strong bactericidal effect on C. sakazakii/C. sakazakii LUX cells (≤10[4]cfu/mL), resulting in a significant reduction in cell numbers, to below the limit of detection (<10cfu/mL). This was observed following a 20h challenge in different brands of infant formula, where samples in the absence of the phage cocktail reached concentrations of ~10[9]cfu/mL. The phage cocktail also demonstrated promise in preventing the establishment of biofilm, as biofilm formation could not be detected for up to 48h post treatment. These results highlight the potential application of this phage preparation for biocontrol of C. sakazakii contamination in reconstituted infant formula and also as a preventative agent against biofilm formation.}, } @article {pmid28458193, year = {2017}, author = {Shi, Y and Huang, C and Gamal El-Din, M and Liu, Y}, title = {Optimization of moving bed biofilm reactors for oil sands process-affected water treatment: The effect of HRT and ammonia concentrations.}, journal = {The Science of the total environment}, volume = {598}, number = {}, pages = {690-696}, doi = {10.1016/j.scitotenv.2017.04.144}, pmid = {28458193}, issn = {1879-1026}, mesh = {Ammonia/*analysis ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Genes, Bacterial ; *Oil and Gas Fields ; Waste Disposal, Fluid ; Water Pollutants, Chemical ; Water Purification/*methods ; }, abstract = {Two moving bed biofilm reactors (MBBRs) were optimized to improve the biodegradation of organic compounds in raw and ozonated OSPW by changing the hydraulic retention time (HRT) and the influent ammonia concentrations. During the five stages, the average COD removal reached 50.8±3.4%, 52.8±6.5%, 54.7±4.3%, 56.3±2.2%, and 58.0±2.3% respectively in raw OSPW MBBR, and 54.6±3.8%, 57.2±7.1%, 55.5±5.8%, 58.3±2.2%, and 60.7±2.3% respectively in ozonated OSPW MBBR. Welch's weighted ANOVA tests show that the increase in ammonia levels significantly improved the COD removal in the two systems, while the HRT was an important parameter for COD decrease in the raw OSPW MBBR. Compared to the HRT, the increase in ammonia concentrations were more beneficial for acid extractable fraction (AEF) degradation and the average AEF removal reached 29.80% (raw OSPW MBBR) and 16.50% (ozonated OSPW MBBR) by the end of the optimization (Stage V; HRT=96h, 60mg/L NH4[+]-N). >98% of the NH4[+]-N was removed in the two MBBR systems, showing good nitrification. Microtoxicity tests showed that no significant correlations were found between HRT/ammonia levels and the OSPW toxicity changes toward V. fischeri. Spearman's rank correlation analysis was applied for q-PCR data, showing that positive correlations between the removal efficiencies of AEF and NSR and NirK gene copies were observed in the raw OSPW MBBR system, while positive correlations between AEF removal efficiency and total bacteria gene, NSR, Nitro, and NirK gene copies were observed in the ozonated OSPW MBBR system.}, } @article {pmid28457900, year = {2017}, author = {Bardbari, AM and Arabestani, MR and Karami, M and Keramat, F and Alikhani, MY and Bagheri, KP}, title = {Correlation between ability of biofilm formation with their responsible genes and MDR patterns in clinical and environmental Acinetobacter baumannii isolates.}, journal = {Microbial pathogenesis}, volume = {108}, number = {}, pages = {122-128}, doi = {10.1016/j.micpath.2017.04.039}, pmid = {28457900}, issn = {1096-1208}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/drug effects/*genetics/isolation & purification/*physiology ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; Cross Infection/microbiology/prevention & control ; DNA, Bacterial/analysis ; Drug Resistance, Multiple, Bacterial/genetics ; Environmental Microbiology ; Female ; Genes, MDR/*genetics/*physiology ; Humans ; Iran ; Male ; Microbial Sensitivity Tests ; Middle Aged ; }, abstract = {Acinetobacter baumannii potential to form biofilm and exhibit multiple antibiotic resistances may be responsible in its survival in hospital environment. Accordingly, our study was aimed to determine the correlation between ability of biofilm formation and the frequency of biofilm related genes with antibiotic resistance phenotypes, and also the categorization of their patterns in clinical and environmental isolates. A total of 75 clinical and 32 environmental strains of the A. baumannii were collected and identified via API 20NE. Antibiotic susceptibility was evaluated by disk diffusion and microdilution broth methods. Biofilm formation assay was performed by microtiter plate method. OXA types and biofilm related genes including BlaOXA-51, BlaOXA-23, BlaOXA-24, BlaOXA-58, bap, blaPER-1, and ompA were amplified by PCR. The rate of MDR A. baumannii in clinical isolates (100%) was higher than environmental (81.2%) isolates (p < 0.05). Among 10 antibiotypes, the predominant resistance pattern in clinical and environmental isolates was antibiotypes I (85.3 and 78.1%, respectively). Analysis of the frequency of blaOXA-23 gene revealed a statistically significant difference between clinical (85.3%) and environmental (68.7%) isolates (p < 0.05). The prevalence of strong biofilm producers in clinical and environmental isolates were 31.2%-58.7%, respectively. In the clinical and environmental isolates, the frequencies of ompA, blaRER-1 and bap genes were 100%, 53.3%, 82.7% and 100%, 37.5%, 84.4% respectively. Statistical analysis revealed a significant correlation between the frequency of MDR isolates and biofilm formation ability (p = 0.008). The high frequency of antibiotype I would be indicated that an outbreak has been happened earlier and an endemic strain is currently being settled in the hospital environment. It would be suggested that if there was no difference in the frequency of pattern I and biofilm formation ability between clinical and environmental isolates, it is a critical point representing the higher risk of bacterial transmission from environment to the patients. The resulting data would be assisted in the improvement of disinfection strategies to better control of nosocomial infections. One dominant resistance pattern has shown among clinical and environmental isolates. The frequency of blaOXA-23 had significant difference between clinical and environmental isolates. The presence of bap gene in the A. baumannii isolates was associated with biofilm formation. There was a significant correlation between multiple drug resistance and biofilm formation. The clinical isolates had a higher ability to form strong biofilms compared to the environmental samples.}, } @article {pmid28457636, year = {2017}, author = {Seneviratne, CJ and Suriyanarayanan, T and Swarup, S and Chia, KHB and Nagarajan, N and Zhang, C}, title = {Transcriptomics Analysis Reveals Putative Genes Involved in Biofilm Formation and Biofilm-associated Drug Resistance of Enterococcus faecalis.}, journal = {Journal of endodontics}, volume = {43}, number = {6}, pages = {949-955}, doi = {10.1016/j.joen.2017.01.020}, pmid = {28457636}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Drug Resistance, Bacterial/genetics ; Enterococcus faecalis/*drug effects/genetics/ultrastructure ; *Gene Expression Profiling ; Genes, Bacterial/*genetics ; Gram-Positive Bacterial Infections/drug therapy/microbiology ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; }, abstract = {INTRODUCTION: Enterococcus faecalis is a gram-positive bacterium associated with endodontic infections and is capable of forming biofilms that can confer drug resistance to the bacterium, resulting in treatment failure. Current knowledge on E. faecalis drug resistance is of a limited and conflicting nature. The present study examined the genetic basis of E. faecalis biofilm formation and drug resistance using a RNA sequencing (RNA-Seq)-based transcriptome approach.

METHODS: Eighteen clinical isolates of E. faecalis were screened for their biofilm formation abilities using the crystal violet assay, colony counting, and confocal imaging. Selected isolates were then evaluated for antibiotic susceptibility in planktonic and biofilm growth modes followed by RNA-Seq analysis of E. faecalis planktonic, biofilm, and vancomycin-treated biofilm samples and Kyoto Encyclopedia of Genes and Genomes mapping in order to identify genes associated with biofilm formation and drug resistance of E. faecalis.

RESULTS: All 18 clinical isolates retained biofilm formation ability and were classified as strong, weak, or laboratory American Type Culture Collection strainlike biofilm formers. Interestingly, both the strong and weak biofilm-forming isolates were uniformly resistant to ampicillin and vancomycin at the treated concentrations (256-4096 μg/mL). RNA-Seq analysis of these isolates identified a total of 163 and 101 differentially regulated genes in planktonic versus biofilm and vancomycin-treated biofilm versus biofilm comparisons, respectively, with significant differences in arsenic resistance operon genes arsR and arsD, sporulation regulatory gene paiA, ABC drug transporter classes, and penicillin-binding proteins.

CONCLUSIONS: The present transcriptomic study revealed putative genes associated with E. faecalis biofilm formation and drug resistance, which will provide a foundation for improved therapeutic strategies against E. faecalis infections in the future.}, } @article {pmid28457635, year = {2017}, author = {Kajwadkar, R and Shin, JM and Lin, GH and Fenno, JC and Rickard, AH and Kapila, YL}, title = {High-purity Nisin Alone or in Combination with Sodium Hypochlorite Is Effective against Planktonic and Biofilm Populations of Enterococcus faecalis.}, journal = {Journal of endodontics}, volume = {43}, number = {6}, pages = {989-994}, doi = {10.1016/j.joen.2017.01.034}, pmid = {28457635}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Disk Diffusion Antimicrobial Tests ; Dose-Response Relationship, Drug ; Drug Therapy, Combination ; Enterococcus faecalis/*drug effects ; Nisin/administration & dosage/*pharmacology ; Sodium Hypochlorite/administration & dosage/*pharmacology ; }, abstract = {INTRODUCTION: Nisin, a broad-spectrum bacteriocin, has recently been highlighted for its biomedical applications. To date, no studies have examined the antimicrobial and antibiofilm properties of high-purity (>95%) nisin (nisin ZP) on Enterococcus faecalis and biofilms formed by this species. We hypothesize that nisin can inhibit E. faecalis and reduce biofilm biomass, and combinations of nisin and sodium hypochlorite (NaOCl) will enhance the antibiofilm properties against E. faecalis biofilms.

METHODS: Using broth cultures, disc diffusion assays, and biofilm assays, we examined the effects of nisin on various E. faecalis growth parameters and biofilm properties (biovolume, thickness, and roughness). Confocal microscopy was used in conjunction with Imaris and Comstat2 software (Kongens Lyngby, Copenhagen, Denmark) to measure and analyze the biofilm properties.

RESULTS: Nisin significantly decreased the growth of planktonic E. faecalis dose dependently. The minimum inhibitory concentrations against E. faecalis strains OG-1 and ATCC 29212 were 15 and 50 μg/mL, and the minimum bactericidal concentrations were 150 and 200 μg/mL, respectively. A reduction in biofilm biovolume and thickness was observed for biofilms treated with nisin at ≥10 μg/mL for 10 minutes. In addition, the combination of nisin with low doses of NaOCl enhanced the antibiofilm properties of both antimicrobial agents.

CONCLUSIONS: Nisin alone or in combination with low concentrations of NaOCl reduces the planktonic growth of E. faecalis and disrupts E. faecalis biofilm structure. Our results suggest that nisin has potential as an adjunctive endodontic therapeutic agent and as an alternative to conventional NaOCl irrigation.}, } @article {pmid28457443, year = {2017}, author = {Nácher-Vázquez, M and Iturria, I and Zarour, K and Mohedano, ML and Aznar, R and Pardo, MÁ and López, P}, title = {Dextran production by Lactobacillus sakei MN1 coincides with reduced autoagglutination, biofilm formation and epithelial cell adhesion.}, journal = {Carbohydrate polymers}, volume = {168}, number = {}, pages = {22-31}, doi = {10.1016/j.carbpol.2017.03.024}, pmid = {28457443}, issn = {1879-1344}, mesh = {Animals ; *Bacterial Adhesion ; *Biofilms ; Dextrans/*biosynthesis ; Epithelial Cells/microbiology ; Fermentation ; Fermented Foods/microbiology ; Latilactobacillus sakei/*metabolism ; Meat Products/microbiology ; Zebrafish ; }, abstract = {In this work we have investigated two dextran-producing lactic acid bacteria, Lactobacillus sakei MN1 and Leuconostoc mesenteroides RTF10, isolated from fermented meat products. These bacteria synthesise dextran when sucrose, but not glucose, is present in the growth medium. The influence of dextran on bacterial aggregation, adhesion and biofilm formation was investigated in cultures challenged with sucrose or glucose. For Lb. sakei MN1, the synthesis of the dextran drastically impaired the three processes; in contrast it had no effect on Lc. mesenteroides RTF10. Therefore, the influence of dextran on probiotic properties of Lb. sakei MN1 was tested in vivo using gnotobiotic zebrafish models. The bacterium efficiently colonised the fish gut and inhibited the killing activity of Vibrio anguillarum NB10[pOT11]. Furthermore, under conditions of dextran synthesis, the adhesion of Lb. sakei MN1 to the epithelial cells decreased, without greatly affecting its anti V. anguillarum activity.}, } @article {pmid28456649, year = {2017}, author = {Bandara, M and Skehel, JM and Kadioglu, A and Collinson, I and Nobbs, AH and Blocker, AJ and Jenkinson, HF}, title = {The accessory Sec system (SecY2A2) in Streptococcus pneumoniae is involved in export of pneumolysin toxin, adhesion and biofilm formation.}, journal = {Microbes and infection}, volume = {19}, number = {7-8}, pages = {402-412}, pmid = {28456649}, issn = {1769-714X}, support = {MC_U105178788/MRC_/Medical Research Council/United Kingdom ; 2011-G1001606/MRC_/Medical Research Council/United Kingdom ; }, mesh = {*Bacterial Adhesion ; Bacterial Proteins/metabolism ; Bacterial Secretion Systems/*genetics/*metabolism ; Biofilms/*growth & development ; Gene Deletion ; Humans ; Streptococcus pneumoniae/*genetics/*metabolism/physiology ; Streptolysins/*metabolism ; }, abstract = {In Streptococcus pneumoniae TIGR4, genes encoding a SecY2A2 accessory Sec system are present within a locus encoding a serine-rich repeat surface protein PsrP. Mutant strains deleted in secA2 or psrP were deficient in biofilm formation, while the ΔsecA2 mutant was reduced in binding to airway epithelial cells. Cell wall protein (CWP) fractions from the ΔsecA2 mutant, but not from the ΔpsrP mutant, were reduced in haemolytic (pneumolysin) activity. Contact-dependent pneumolysin (Ply) activity of wild type TIGR4 cells was ten-fold greater than that of ΔsecA2 mutant cells suggesting that Ply was not active at the ΔsecA2 cell surface. Ply protein was found to be present in the CWP fraction from the ΔsecA2 mutant, but showed aberrant electrophoretic migration indicative of protein modification. Proteomic analyses led to the discovery that the ΔsecA2 mutant CWP fraction was deficient in two glycosidases as well as other enzymes involved in carbohydrate metabolism. Taken collectively the results suggest that positioning of Ply into the cell wall compartment in active form, together with glycosyl hydrolases and adhesins, requires a functional accessory Sec system.}, } @article {pmid28455641, year = {2017}, author = {Feng, LJ and Jia, R and Sun, JY and Wang, J and Lv, ZH and Mu, J and Yang, GF}, title = {Response of performance and bacterial community to oligotrophic stress in biofilm systems for raw water pretreatment.}, journal = {Biodegradation}, volume = {28}, number = {4}, pages = {231-244}, doi = {10.1007/s10532-017-9792-y}, pmid = {28455641}, issn = {1572-9729}, mesh = {Bacteria/*metabolism ; Biodegradation, Environmental ; Biodiversity ; *Biofilms ; Biological Oxygen Demand Analysis ; Phylogeny ; Principal Component Analysis ; *Stress, Physiological ; Water Pollutants, Chemical/isolation & purification ; Water Purification/*methods ; }, abstract = {Understanding the dynamics of performance and bacterial community of biofilm under oligotrophic stress is necessary for the process optimization and risk management in biofilm systems for raw water pretreatment. In this study, biofilm obtained from a pilot-scale biofilm reactor was inoculated into a pilot-scale experimental tank for the treatment of oligotrophic raw water. Results showed that the removal of NH4[+]-N was impaired in biofilm systems when influent NH4[+]-N was less than 0.35 mg L[-1] or NH4[+]-N loading rate of less than 7.51 mg L[-1] day[-1]. The dominant bacteria detected in biofilm of different carrier were obvious distinct from phylum to genus level under oligotrophic stress. The dominant bacteria in elastic stereo media carrier changed from Proteobacteria (51.1%) to Firmicutes (32.7%), while Proteobacteria was always dominant in suspended ball carrier after long-term operation under oligotrophic conditions. Oligotrophic stress largely decreased the functional bacteria for the removal of nitrogen and organics including many genera in Proteobacteria and Nitrospirae, but increased several genera with spore forming organisms or potential bacterial pathogens in ESM carrier mainly including Bacillus, Mycobacterium, Pseudomonas, etc.}, } @article {pmid28453851, year = {2017}, author = {Zapotoczna, M and Forde, É and Hogan, S and Humphreys, H and O'Gara, JP and Fitzgerald-Hughes, D and Devocelle, M and O'Neill, E}, title = {Eradication of Staphylococcus aureus Biofilm Infections Using Synthetic Antimicrobial Peptides.}, journal = {The Journal of infectious diseases}, volume = {215}, number = {6}, pages = {975-983}, doi = {10.1093/infdis/jix062}, pmid = {28453851}, issn = {1537-6613}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/*drug therapy ; Cytokines/blood ; Disease Models, Animal ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Peptides/*pharmacology ; Peptides, Cyclic/pharmacology ; Rats ; Rats, Sprague-Dawley ; Staphylococcal Infections/*drug therapy ; Vancomycin/administration & dosage ; }, abstract = {Here, we demonstrate that antimicrobial peptides (AMPs) are an effective antibiofilm treatment when applied as catheter lock solutions (CLSs) against S. aureus biofilm infections. The activity of synthetic AMPs (Bac8c, HB43, P18, Omiganan, WMR, Ranalexin, and Polyphemusin) was measured against early and mature biofilms produced by methicillin-resistant S. aureus and methicillin-susceptible S. aureus isolates from patients with device-related infections grown under in vivo-relevant biofilm conditions. The cytotoxic and hemolytic activities of the AMPs against human cells and their immunomodulatory potential in human blood were also characterized. The D-Bac8c2,5Leu variant emerged as the most effective AMP during in vitro studies and was also highly effective in eradicating S. aureus biofilm infection when used in a CLS rat central venous catheter infection model. These data support the potential use of D-Bac8c2,5Leu, alone or in combination with other AMPs, in the treatment of S. aureus intravenous catheter infections.}, } @article {pmid28453568, year = {2017}, author = {Luo, J and Dong, B and Wang, K and Cai, S and Liu, T and Cheng, X and Lei, D and Chen, Y and Li, Y and Kong, J and Chen, Y}, title = {Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.}, journal = {PloS one}, volume = {12}, number = {4}, pages = {e0176883}, pmid = {28453568}, issn = {1932-6203}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Caenorhabditis elegans ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Drug Therapy, Combination ; Female ; Flavonoids/*pharmacology ; Interferon-gamma/metabolism ; Interleukin-4/metabolism ; Mice, Inbred BALB C ; Peritoneum ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/*drug therapy/metabolism/microbiology ; Pseudomonas Infections/*drug therapy/metabolism/microbiology ; Pseudomonas aeruginosa/*drug effects/*pathogenicity/physiology/ultrastructure ; Quorum Sensing/*drug effects ; Virulence/drug effects ; Virulence Factors/metabolism ; }, abstract = {The quorum sensing (QS) circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs) of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A) regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed mitigation of the inflammatory response and reduced cell infiltration in the peritoneal tissue surrounding the implants after baicalin treatment. Measurement of the cytokine levels in the peritoneal lavage fluid of mice in the baicalin treatment group revealed a decrease in IL-4, an increase in interferon γ (IFN-γ), and a reversed IFN-γ/IL-4 ratio compared with the control group, indicating that baicalin treatment activated the Th1-induced immune response to expedite bacterial load clearance. Based on these results, baicalin might be a potent QS inhibitor and anti-biofilm agent for combating Pseudomonas aeruginosa biofilm-related infections.}, } @article {pmid28452767, year = {2017}, author = {Boltz, JP and Smets, BF and Rittmann, BE and van Loosdrecht, MCM and Morgenroth, E and Daigger, GT}, title = {From biofilm ecology to reactors: a focused review.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {75}, number = {7-8}, pages = {1753-1760}, doi = {10.2166/wst.2017.061}, pmid = {28452767}, issn = {0273-1223}, mesh = {Bacteria/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Bioreactors/*microbiology ; Ecology ; Wastewater/chemistry/microbiology ; Water Purification ; }, abstract = {Biofilms are complex biostructures that appear on all surfaces that are regularly in contact with water. They are structurally complex, dynamic systems with attributes of primordial multicellular organisms and multifaceted ecosystems. The presence of biofilms may have a negative impact on the performance of various systems, but they can also be used beneficially for the treatment of water (defined herein as potable water, municipal and industrial wastewater, fresh/brackish/salt water bodies, groundwater) as well as in water stream-based biological resource recovery systems. This review addresses the following three topics: (1) biofilm ecology, (2) biofilm reactor technology and design, and (3) biofilm modeling. In so doing, it addresses the processes occurring in the biofilm, and how these affect and are affected by the broader biofilm system. The symphonic application of a suite of biological methods has led to significant advances in the understanding of biofilm ecology. New metabolic pathways, such as anaerobic ammonium oxidation (anammox) or complete ammonium oxidation (comammox) were first observed in biofilm reactors. The functions, properties, and constituents of the biofilm extracellular polymeric substance matrix are somewhat known, but their exact composition and role in the microbial conversion kinetics and biochemical transformations are still to be resolved. Biofilm grown microorganisms may contribute to increased metabolism of micro-pollutants. Several types of biofilm reactors have been used for water treatment, with current focus on moving bed biofilm reactors, integrated fixed-film activated sludge, membrane-supported biofilm reactors, and granular sludge processes. The control and/or beneficial use of biofilms in membrane processes is advancing. Biofilm models have become essential tools for fundamental biofilm research and biofilm reactor engineering and design. At the same time, the divergence between biofilm modeling and biofilm reactor modeling approaches is recognized.}, } @article {pmid28452377, year = {2017}, author = {Xiao, J and Hara, AT and Kim, D and Zero, DT and Koo, H and Hwang, G}, title = {Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface.}, journal = {International journal of oral science}, volume = {9}, number = {2}, pages = {74-79}, pmid = {28452377}, issn = {2049-3169}, support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R03 DE025728/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Dental Enamel/*microbiology ; Fructose ; Glucose ; Humans ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Microradiography ; Microscopy, Confocal ; Saliva/chemistry ; Sucrose ; Surface Properties ; Tooth Demineralization/*microbiology ; }, abstract = {To investigate how the biofilm three-dimensional (3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters (microcolonies). Acidic regions (pH<5.5) were found only in the interior of microcolonies, which impedes rapid neutralization (taking more than 120 min for neutralization). Glucose exposure rapidly re-created the acidic niches, indicating formation of diffusion barriers associated with microcolonies structure. Enamel demineralization (white spots), rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions (white spot like) on teeth.}, } @article {pmid28452235, year = {2017}, author = {Mizan, MFR and Bang, HJ and Sadekuzzaman, M and Lee, N and Kim, TJ and Ha, SD}, title = {Molecular characteristics, biofilm-forming abilities, and quorum sensing molecules in Vibrio parahaemolyticus strains isolated from marine and clinical environments in Korea.}, journal = {Biofouling}, volume = {33}, number = {5}, pages = {369-378}, doi = {10.1080/08927014.2017.1316840}, pmid = {28452235}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Chromatography, High Pressure Liquid/methods ; Clinical Laboratory Techniques/*methods ; *Environmental Microbiology/standards ; Food Microbiology/methods ; Foodborne Diseases/microbiology/prevention & control ; Humans ; *Quorum Sensing ; Real-Time Polymerase Chain Reaction/methods ; Republic of Korea ; Seafood/*microbiology ; Sensitivity and Specificity ; Species Specificity ; Vibrio parahaemolyticus/genetics/*isolation & purification/pathogenicity/physiology ; Virulence/genetics ; }, abstract = {Vibrio parahaemolyticus is an inhabitant of marine and estuarine environments and causes seafood-borne gastroenteritis in humans. In this study, an UltraFast LabChip Real-Time PCR assay was evaluated for rapid detection and quantification of pathogenic V. parahaemolyticus isolates. Escherichia coli and Vibrio harveyi were used as negative controls. Twenty-six tdh-positive, biofilm-producing V. parahaemolyticus isolates were analyzed by repetitive extragenic palindromic-polymerase chain reaction (REP-PCR). REP-PCR analysis showed that the majority of the V. parahaemolyticus isolates originated from seafood and that clinical specimens formed two major clusters at 92.8% and 32% similarity levels. The presence and quantification of Autoinducer-2 was carried out using high-performance liquid chromatography with fluorescence detection (HPLC-FLD) after derivatization of Autoinducer-2 with 2, 3-diaminonaphthalene. The presence of tdh-positive V. parahaemolyticus in marine samples highlights the need for constant environmental monitoring to protect public health.}, } @article {pmid28448807, year = {2017}, author = {Abdul Razak, F and Baharuddin, BA and Akbar, EFM and Norizan, AH and Ibrahim, NF and Musa, MY}, title = {Alternative sweeteners influence the biomass of oral biofilm.}, journal = {Archives of oral biology}, volume = {80}, number = {}, pages = {180-184}, doi = {10.1016/j.archoralbio.2017.04.014}, pmid = {28448807}, issn = {1879-1506}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; *Biomass ; Dental Plaque/microbiology ; Extracellular Matrix/drug effects ; Microscopy, Electron, Scanning ; Saliva/chemistry ; Streptococcus mitis/drug effects ; Streptococcus mutans/drug effects ; Streptococcus sanguis/drug effects ; Surface Properties ; Sweetening Agents/*pharmacology ; Xylitol/pharmacology ; }, abstract = {OBJECTIVE: Compact-structured oral biofilm accumulates acids that upon prolonged exposure to tooth surface, causes demineralisation of enamel. This study aimed to assess the effect of alternative sweeteners Equal Stevia[®], Tropicana Slim[®], Pal Sweet[®] and xylitol on the matrix-forming activity of plaque biofilm at both the early and established stages of formation.

METHODS: Saliva-coated glass beads (sGB) were used as substratum for the adhesion of a mixed-bacterial suspension of Streptococcus mutans, Streptococcus sanguinis and Streptococcus mitis. Biofilms formed on sGB at 3h and 24h represented the early and established-plaque models. The biofilms were exposed to three doses of the sweeteners (10%), introduced at three intervals to simulate the exposure of dental plaque to sugar during three consecutive food intakes. The treated sGB were (i) examined under the SEM and (ii) collected for turbidity reading. The absorbance indicated the amount of plaque mass produced. Analysis was performed comparative to sucrose as control.

RESULTS: Higher rate of bacterial adherence was determined during the early compared to established phases of formation. Comparative to the sweeteners, sucrose showed a 40% increase in bacterial adherence and produced 70% more plaque-mass. Bacterial counts and SEM micrographs exhibited absence of matrix in all the sweetener-treated biofilms at the early phase of formation. At the established phase, presence of matrix was detected but at significantly lower degree compared to sucrose (p<0.05).

CONCLUSION: Alternatives sweeteners promoted the formation of oral biofilm with lighter mass and lower bacterial adherence. Hence, suggesting alternative sweeteners as potential antiplaque agents.}, } @article {pmid28448633, year = {2017}, author = {Scoffield, JA and Duan, D and Zhu, F and Wu, H}, title = {A commensal streptococcus hijacks a Pseudomonas aeruginosa exopolysaccharide to promote biofilm formation.}, journal = {PLoS pathogens}, volume = {13}, number = {4}, pages = {e1006300}, pmid = {28448633}, issn = {1553-7374}, support = {K99 DE025913/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/metabolism ; Animals ; *Biofilms ; Cystic Fibrosis/*microbiology ; Drosophila melanogaster ; Humans ; Polysaccharides, Bacterial/*metabolism ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/growth & development/isolation & purification/*physiology ; Respiratory System/microbiology ; Symbiosis ; }, abstract = {Pseudomonas aeruginosa causes devastating chronic pulmonary infections in cystic fibrosis (CF) patients. Although the CF airway is inhabited by diverse species of microorganisms interlaced within a biofilm, many studies focus on the sole contribution of P. aeruginosa pathogenesis in CF morbidity. More recently, oral commensal streptococci have been identified as cohabitants of the CF lung, but few studies have explored the role these bacteria play within the CF biofilm. We examined the interaction between P. aeruginosa and oral commensal streptococci within a dual species biofilm. Here we report that the CF P. aeruginosa isolate, FRD1, enhances biofilm formation and colonization of Drosophila melanogaster by the oral commensal Streptococcus parasanguinis. Moreover, production of the P. aeruginosa exopolysaccharide, alginate, is required for the promotion of S. parasanguinis biofilm formation and colonization. However, P. aeruginosa is not promoted in the dual species biofilm. Furthermore, we show that the streptococcal adhesin, BapA1, mediates alginate-dependent enhancement of the S. parasanguinis biofilm in vitro, and BapA1 along with another adhesin, Fap1, are required for the in vivo colonization of S. parasanguinis in the presence of FRD1. Taken together, our study highlights a new association between streptococcal adhesins and P. aeruginosa alginate, and reveals a mechanism by which S. parasanguinis potentially colonizes the CF lung and interferes with the pathogenesis of P. aeruginosa.}, } @article {pmid28446778, year = {2017}, author = {Rocha, FAC and Alves, AMCV and Rocha, MFG and Cordeiro, RA and Brilhante, RSN and Pinto, ACMD and Nunes, RM and Girão, VCC and Sidrim, JJC}, title = {Tumor necrosis factor prevents Candida albicans biofilm formation.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {1206}, pmid = {28446778}, issn = {2045-2322}, mesh = {Animals ; Anti-Infective Agents/*metabolism ; Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/*physiology ; Humans ; Microbial Sensitivity Tests ; Rats ; Tumor Necrosis Factor-alpha/*metabolism ; }, abstract = {Candida species are commensals but some develop biofilms in prosthetic materials and host surfaces that may represent up to 30% of deaths related to infections, particularly in immunosuppressed patients. Tumor necrosis factor (TNF) exhibits a plethora of functions in host defense mechanisms whereas excessive release of TNF in inflammation promotes tissue damage. Cytokines released in an inflammatory milieu may influence the development of microorganisms either by promoting their growth or displaying antimicrobial activity. In protozoa, TNF may affect growth by coupling through a lectin-like domain, distinct from TNF receptors. TNF was also shown to interact with bacteria via a mechanism that does not involve classical TNF receptors. Using an in vitro C. albicans biofilm model, we show that TNF dose-dependently prevents biofilm development that is blocked by incubating TNF with N,N'-diacetylchitobiose, a major carbohydrate component of C. albicans cell wall. This finding represents a relevant and hitherto unknown mechanism that adds to the understanding of why TNF blockade is associated with opportunistic C. albicans infections.}, } @article {pmid28442545, year = {2017}, author = {Bedi, B and Maurice, NM and Ciavatta, VT and Lynn, KS and Yuan, Z and Molina, SA and Joo, M and Tyor, WR and Goldberg, JB and Koval, M and Hart, CM and Sadikot, RT}, title = {Peroxisome proliferator-activated receptor-γ agonists attenuate biofilm formation by Pseudomonas aeruginosa.}, journal = {FASEB journal : official publication of the Federation of American Societies for Experimental Biology}, volume = {31}, number = {8}, pages = {3608-3621}, pmid = {28442545}, issn = {1530-6860}, support = {I01 BX001786/BX/BLRD VA/United States ; R01 HL102167/HL/NHLBI NIH HHS/United States ; R01 HL116958/HL/NHLBI NIH HHS/United States ; T32 GM008367/GM/NIGMS NIH HHS/United States ; }, mesh = {Aryldialkylphosphatase/genetics/metabolism ; Bacterial Proteins/*pharmacology ; Biofilms/*growth & development ; Cell Line ; Epithelial Cells/microbiology ; Gene Expression Regulation/physiology ; Humans ; Mutation ; PPAR gamma/*agonists ; Pseudomonas aeruginosa/*drug effects/genetics/*physiology ; Quorum Sensing ; }, abstract = {Pseudomonas aeruginosa is a significant contributor to recalcitrant multidrug-resistant infections, especially in immunocompromised and hospitalized patients. The pathogenic profile of P. aeruginosa is related to its ability to secrete a variety of virulence factors and to promote biofilm formation. Quorum sensing (QS) is a mechanism wherein P. aeruginosa secretes small diffusible molecules, specifically acyl homo serine lactones, such as N-(3-oxo-dodecanoyl)-l-homoserine lactone (3O-C12-HSL), that promote biofilm formation and virulence via interbacterial communication. Strategies that strengthen the host's ability to inhibit bacterial virulence would enhance host defenses and improve the treatment of resistant infections. We have recently shown that peroxisome proliferator-activated receptor γ (PPARγ) agonists are potent immunostimulators that play a pivotal role in host response to virulent P. aeruginosa Here, we show that QS genes in P. aeruginosa (strain PAO1) and 3O-C12-HSL attenuate PPARγ expression in bronchial epithelial cells. PAO1 and 3O-C12-HSL induce barrier derangements in bronchial epithelial cells by lowering the expression of junctional proteins, such as zonula occludens-1, occludin, and claudin-4. Expression of these proteins was restored in cells that were treated with pioglitazone, a PPARγ agonist, before infection with PAO1 and 3O-C12-HSL. Barrier function and bacterial permeation studies that have been performed in primary human epithelial cells showed that PPARγ agonists are able to restore barrier integrity and function that are disrupted by PAO1 and 3O-C12-HSL. Mechanistically, we show that these effects are dependent on the induction of paraoxonase-2, a QS hydrolyzing enzyme, that mitigates the effects of QS molecules. Importantly, our data show that pioglitazone, a PPARγ agonist, significantly inhibits biofilm formation on epithelial cells by a mechanism that is mediated via paraoxonase-2. These findings elucidate a novel role for PPARγ in host defense against P. aeruginosa Strategies that activate PPARγ can provide a therapeutic complement for treatment of resistant P. aeruginosa infections.-Bedi, B., Maurice, N. M., Ciavatta, V. T., Lynn, K. S., Yuan, Z., Molina, S. A., Joo, M., Tyor, W. R., Goldberg, J. B., Koval, M., Hart, C. M., Sadikot, R. T. Peroxisome proliferator-activated receptor-γ agonists attenuate biofilm formation by Pseudomonas aeruginosa.}, } @article {pmid28442426, year = {2017}, author = {Yi, H and Yuan, B and Liu, J and Zhu, D and Wu, Y and Wang, M and Jia, R and Sun, K and Yang, Q and Chen, S and Liu, M and Chen, X and Cheng, A}, title = {Identification of a wza-like gene involved in capsule biosynthesis, pathogenicity and biofilm formation in Riemerella anatipestifer.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {442-450}, doi = {10.1016/j.micpath.2017.04.023}, pmid = {28442426}, issn = {1096-1208}, mesh = {Amino Acid Sequence ; Animals ; Bacterial Capsules/*genetics/*physiology ; Bacterial Outer Membrane Proteins/genetics/physiology ; Biofilms/*growth & development ; Desiccation ; Gene Deletion ; Genes, Bacterial ; Hydrophobic and Hydrophilic Interactions ; Lethal Dose 50 ; Microscopy, Electron, Transmission ; Mutation ; Oxidative Stress ; Poultry Diseases/microbiology ; Riemerella/*genetics/*metabolism/*pathogenicity ; Virulence/*genetics ; }, abstract = {Duck infectious serositis is the most serious bacterial disease of ducks. It is caused by Riemerella anatipestifer (RA) infection. The capsule plays an important role in virulence of many pathogenic bacteria. In addition, the capsule has some key biological features. However, few studies have explored the characteristics of the RA capsule. In this study, we mainly constructed a capsular mutants of RA by inactivating the wza gene using homologous recombination. We found that the mutant was failed to produce a capsule layer. The mutant was less resistant to killing by the host complement or by desiccation and oxidative stress. Furthermore, the mutant strain was more hydrophobic, more able to auto-aggregate and underwent increased biofilm formation. Moreover, the mutant was less virulent than the wild-type in vivo studies. In summary, we found that the RA capsule was involved in the desiccation and oxidative stress, surface hydrophobicity, complement-mediated killing, biofilm formation, and virulence.}, } @article {pmid28440961, year = {2017}, author = {Kapoor, V and Rai, R and Thiyagarajan, D and Mukherjee, S and Das, G and Ramesh, A}, title = {A Nonbactericidal Zinc-Complexing Ligand as a Biofilm Inhibitor: Structure-Guided Contrasting Effects on Staphylococcus aureus Biofilm.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {18}, number = {15}, pages = {1502-1509}, doi = {10.1002/cbic.201700139}, pmid = {28440961}, issn = {1439-7633}, mesh = {Benzothiazoles/chemical synthesis/*pharmacology/toxicity ; Biofilms/*drug effects ; Chelating Agents/chemical synthesis/*pharmacology/toxicity ; Edetic Acid/pharmacology/toxicity ; HeLa Cells ; Humans ; Microscopy, Fluorescence ; Semicarbazones/chemical synthesis/*pharmacology/toxicity ; Staphylococcus aureus/*drug effects ; Zinc/*chemistry ; }, abstract = {Zinc-complexing ligands are prospective anti-biofilm agents because of the pivotal role of zinc in the formation of Staphylococcus aureus biofilm. Accordingly, the potential of a thiosemicarbazone (compound C1) and a benzothiazole-based ligand (compound C4) in the prevention of S. aureus biofilm formation was assessed. Compound C1 displayed a bimodal activity, hindering biofilm formation only at low concentrations and promoting biofilm growth at higher concentrations. In the case of C4, a dose-dependent inhibition of S. aureus biofilm growth was observed. Atomic force microscopy analysis suggested that at higher concentrations C1 formed globular aggregates, which perhaps formed a substratum that favored adhesion of cells and biofilm formation. In the case of C4, zinc supplementation experiments validated zinc complexation as a plausible mechanism of inhibition of S. aureus biofilm. Interestingly, C4 was nontoxic to cultured HeLa cells and thus has promise as a therapeutic anti-biofilm agent. The essential understanding of the structure-driven implications of zinc-complexing ligands acquired in this study might assist future screening regimes for identification of potent anti-biofilm agents.}, } @article {pmid28440891, year = {2018}, author = {André, CB and Dos Santos, A and Pfeifer, CS and Giannini, M and Girotto, EM and Ferracane, JL}, title = {Evaluation of three different decontamination techniques on biofilm formation, and on physical and chemical properties of resin composites.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {106}, number = {3}, pages = {945-953}, pmid = {28440891}, issn = {1552-4981}, support = {K02 DE025280/DE/NIDCR NIH HHS/United States ; U01 DE023756/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Chloramines/pharmacology ; Composite Resins/*chemistry/radiation effects ; Decontamination/*methods ; Dental Materials ; Disinfectants/pharmacology ; Ethanol/pharmacology ; Porosity ; Streptococcus mutans/drug effects ; Tosyl Compounds/pharmacology ; Ultraviolet Rays ; }, abstract = {OBJECTIVES: This study evaluated three different sterilization/disinfection techniques for resin composites on bacterial growth and surface modification after decontamination.

METHODS: Two resin composites were sterilized/disinfected with three different techniques: UV light, 1% chloramine T, and 70% ethanol. Four different times were used for each technique to determine the shortest time that the solution or UV light was effective. The influence of sterilization/disinfection technique on bacterial growth was evaluated by analyzing the metabolic activity, using the AlamarBlue™ assay, bacterial viability, and SEM images from biofilms of Streptococcus mutans. The surface change, after the process, was analyzed with ATR/FTIR and SEM images. The solutions used for decontamination (1% chloramine-T and 70% ethanol) were analyzed with [1] H-NMR to identify any resin compounds leached during the process.

RESULTS: One minute of decontamination was efficient for all three methods tested. Chloramine-T increased the surface porosity on resin composites, no changes were observed for UV light and 70% ethanol, however, [1] H-NMR identified leached monomers only when 70% ethanol was used. No chemical change of the materials was found under ATR/FTIR analyses after the decontamination process. Chloramine-T, with no previous wash, increased the bacterial viability for both resin composites and increased the bacterial metabolism for the resin composite without fluoride.

CONCLUSION: UV light had no interference on the resin composites properties tested using 1 min of exposure compared to the other decontamination methods. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 945-953, 2018.}, } @article {pmid28440203, year = {2017}, author = {Aswathanarayan, JB and Vittal, RR}, title = {Antimicrobial, Biofilm Inhibitory and Anti-infective Activity of Metallic Nanoparticles Against Pathogens MRSA and Pseudomonas aeruginosa PA01.}, journal = {Pharmaceutical nanotechnology}, volume = {5}, number = {2}, pages = {148-153}, doi = {10.2174/2211738505666170424121944}, pmid = {28440203}, issn = {2211-7393}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Copper/chemistry ; Drug Resistance, Bacterial ; Gold ; HT29 Cells ; Humans ; Iron ; Metal Nanoparticles/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Particle Size ; Plankton/drug effects ; Pseudomonas aeruginosa/*drug effects ; Zinc Oxide/chemistry ; }, abstract = {BACKGROUND: The emergence of drug resistant pathogens is a major concern to the scientific community. Novel approaches such as the use of functionalized nanomaterials with antimicrobial activity is required to treat infectious diseases.

OBJECTIVE: In the present study, the metallic nanoparticles (iron, gold, zinc oxide and copper oxide) were evaluated for the antimicrobial, biofilm inhibitory and anti-infective activity against human pathogens methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa PA01.

METHODS: The efficacy of nanoparticles on the planktonic growth of clinically relevant pathogens was determined by MIC. Further, the effect of nanoparticles was studied on their biofilms using crystal violet microtiter plate assay and fluorescent microscopy. The cytotoxicity of nanoparticles was studied in HT29 cell line.

RESULTS: The nanoparticles of copper and zinc oxide (size < 50 nm) were more effective against Grampositive and Gram-negative pathogens in comparison to gold and iron nanoparticles. The ZnO nanoparticles had an MIC in the range of 3.125 μg/ ml and 6.25 μg/ ml against the tested pathogens. The nanoparticles at the tested concentration reduced biofilm burden by > 75% in the pathogens. The nanoparticles showed cytotoxicity in HT 29 at 20 μg/ ml.

CONCLUSION: The results of the study showed that of all the tested nanoparticles, ZnO nanoparticles had significant antimicrobial activity against the drug resistant pathogens and could be used at concentrations less toxic to mammalian cells. Hence, ZnO nanoparticles have the potential for the design of novel antibacterial agents and therapeutics.}, } @article {pmid28438824, year = {2017}, author = {Luther, MK and Mermel, LA and LaPlante, KL}, title = {Comparison of linezolid and vancomycin lock solutions with and without heparin against biofilm-producing bacteria.}, journal = {American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists}, volume = {74}, number = {9}, pages = {e193-e201}, doi = {10.2146/ajhp150804}, pmid = {28438824}, issn = {1535-2900}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/microbiology/prevention & control ; Catheters, Indwelling/adverse effects ; Central Venous Catheters/adverse effects ; Drug Evaluation, Preclinical ; Drug Interactions ; Enterococcus faecalis/drug effects/physiology ; Heparin/*pharmacology ; Humans ; Linezolid/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Microbial Sensitivity Tests ; Staphylococcus aureus/drug effects/physiology ; Staphylococcus epidermidis/drug effects/physiology ; Vancomycin/*pharmacology ; }, abstract = {PURPOSE: The activity of linezolid and vancomycin lock solutions against biofilm-producing strains of Staphylococcus aureus, S. epidermidis, and Enterococcus faecalis was studied.

METHODS: Two strains each of methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), and S. epidermidis, and 1 strain of vancomycin-susceptible E. faecalis and vancomycin-resistant E. faecalis were tested against vancomycin and linezolid to assess prevention of biofilm formation and eradication of these pathogens within a formed biofilm. Activity was also tested in a 72-hour in vitro central venous catheter (CVC) model. After 24 hours of biofilm growth in a CVC, a lock solution containing vancomycin (2 or 5 mg/mL) or linezolid (1 or 2 mg/mL) alone or in combination with heparin sodium (5,000 units/mL with benzyl alcohol 0.45%) was instilled and incubated at 35 °C for 72 hr. Heparin and 0.9% sodium chloride injection were also tested.

RESULTS: Linezolid and vancomycin prevented biofilm formation below the minimum inhibitory concentration for 88% and 25% of isolates tested, respectively. The addition of preservative-containing heparin decreased the activity of vancomycin and linezolid lock solutions against all strains. Vancomycin 2- and 5-mg/mL lock solutions had the most activity against MSSA and E. faecalis strains (p < 0.01). Linezolid 2 mg/mL was the most active lock solution against the MRSA strains tested (p < 0.01). There were no significant differences in vancomycin or linezolid lock solution activity against S. epidermidis.

CONCLUSION: Heparin reduced activity of vancomycin and linezolid lock solutions against S. aureus, S. epidermidis, and E. faecalis biofilms. While linezolid or vancomycin lock solution reduced overall biofilm burden, it did not completely eradicate the bacteria at tested concentrations.}, } @article {pmid28434696, year = {2017}, author = {Leary, JT and Werger, MM and Broach, WH and Shaw, LN and Santoni, BG and Bernasek, TL and Lyons, ST}, title = {Complete Eradication of Biofilm From Orthopedic Materials.}, journal = {The Journal of arthroplasty}, volume = {32}, number = {8}, pages = {2513-2518}, doi = {10.1016/j.arth.2017.03.050}, pmid = {28434696}, issn = {1532-8406}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Chromium Alloys ; Ethanol ; Humans ; Metals ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Orthopedics ; Prostheses and Implants ; Prosthesis-Related Infections/*drug therapy/*prevention & control ; Staphylococcal Infections/*prevention & control ; Staphylococcus aureus ; Staphylococcus epidermidis ; Sterilization/*methods ; }, abstract = {BACKGROUND: Interest exists in finding alternatives to current management strategies in periprosthetic joint infections, which typically include a 2-stage revision with placement of an antibiotic spacer and delayed placement of a new implant. We studied the efficacy of autoclaving, ultrasonication, and mechanical scrubbing for sterilization and biofilm eradication on infected cobalt-chrome discs.

METHODS: Strains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on the discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication, (3) autoclave + saline scrub, (4) autoclave + 4% chlorhexidine (CHC) scrub, and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy.

RESULTS: Relative to nontreated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. Biofilm removal was maximized with the combined treatment of autoclaving and CHC scrub for MRSA252 (100%) and RP62A (99.5%). The addition of sonication between autoclaving and CHC scrubbing resulted in no statistically significant improvement in biofilm removal. High-resolution scanning electron microscopy revealed no cells or biofilm for this combined treatment.

CONCLUSION: Using 2 commonly encountered bacterial strains in periprosthetic joint infection, infected cobalt-chrome discs were sterilized and eradicated of residual biofilm with a combination of autoclaving and CHC scrubbing.}, } @article {pmid28433912, year = {2017}, author = {Cui, B and Liu, X and Yang, Q and Li, J and Zhou, X and Peng, Y}, title = {Achieving partial denitrification through control of biofilm structure during biofilm growth in denitrifying biofilter.}, journal = {Bioresource technology}, volume = {238}, number = {}, pages = {223-231}, doi = {10.1016/j.biortech.2017.04.034}, pmid = {28433912}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; *Denitrification ; Nitrates ; Nitrites ; }, abstract = {Partial denitrification was one of most effective ways to provide nitrite for annamox; whereas very limited research has been done to achieve nitrite accumulation in biofilm system. In this study, partial denitrification was studied in a lab-scale denitrifying biofilter (DNBF). The results showed biofilm structure variations caused the differences between nitrate specific reduction rate (NaSRR) and nitrite specific reduction rate (NiSRR), which led to nitrite accumulation in different degree at different biofilm formation phases. Hydrodynamic conditions also significantly influenced biofilm structure, nitrate and nitrite reduction activities. At the filtration velocity of 3.86mh[-1], not only biofilm structure, NaSRR and NiSRR kept relatively stable, but also 60% of nitrite accumulation and no nitrate in the effluent were achieved. Furthermore, Thauera genus bacteria, benefited for nitrite accumulation, became the dominant communities in high nitrite accumulation conditions. The partial denitrification combine with anammox in biofilter have the great potential applied in WWTPs.}, } @article {pmid28432951, year = {2017}, author = {Li, J and Sun, S and Yan, P and Fang, L and Yu, Y and Xiang, Y and Wang, D and Gong, Y and Gong, Y and Zhang, Z}, title = {Microbial communities in the functional areas of a biofilm reactor with anaerobic-aerobic process for oily wastewater treatment.}, journal = {Bioresource technology}, volume = {238}, number = {}, pages = {7-15}, doi = {10.1016/j.biortech.2017.04.033}, pmid = {28432951}, issn = {1873-2976}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Nitrogen ; *Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Microbial communities in the functional areas of biofilm reactors with large height-diameter ratio using the anaerobic-aerobic (A/O) reflux process was investigated to treat heavy oil refinery wastewater without pretreatment. In the process, chemical oxygen demand (COD) and total nitrogen (TN) removal reached 93.2% and 82.8%, and the anaerobic biofilm reactor was responsible for 95% and 99%, respectively. Areas for hydrolysis acidification and acetic acid production, methane production, and COD recovery were obvious in the anaerobic reactor. Among all areas, area for hydrolysis acidification and acetic acid production was the key factor to improve COD removal efficiency. High throughput sequencing of 16S rDNA gene showed that the native community was mainly composed of functional groups for hydrocarbon degradation, syntrophic bacteria union body, methanogenesis, nitrification, denitrification, and sulfate reduction. The deviations between predicted values and actual COD and TN removal were less than 5% in the optimal prediction model.}, } @article {pmid28432491, year = {2017}, author = {Nechaeva, OV and Tikhomirova, EI and Zayarsky, DA and Bespalova, NV and Glinskaya, EV and Shurshalova, NF and Al Bayati, BM and Babailova, AI}, title = {Anti-Biofilm Activity of Polyazolidinammonium Modified with Iodine Hydrate Ions against Microbial Biofilms of Uropathogenic Coliform Bacteria.}, journal = {Bulletin of experimental biology and medicine}, volume = {162}, number = {6}, pages = {781-783}, doi = {10.1007/s10517-017-3712-3}, pmid = {28432491}, issn = {1573-8221}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Azoles/chemical synthesis/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Gentian Violet ; Iodine/chemistry ; Microbial Sensitivity Tests ; Polymers/chemical synthesis/*pharmacology ; Quaternary Ammonium Compounds/chemical synthesis/*pharmacology ; Uropathogenic Escherichia coli/*drug effects/pathogenicity/physiology ; Virulence ; }, abstract = {The dynamics of microbial biofilm formation by standard strain and by clinical strains of uropathogenic coliform bacteria was investigated in vitro and the effect of sublethal concentrations of the polymer compound polyazolidinammonium modified with iodine hydrate ions on the initial stages of biofilm formation was assessed. Treatment of immunological plate wells with the polymeric compound prevented film formation, especially in case of clinical E. coli strain carrying FimH virulence gene.}, } @article {pmid28432092, year = {2017}, author = {Yan, F and Yu, Y and Gozzi, K and Chen, Y and Guo, JH and Chai, Y}, title = {Genome-Wide Investigation of Biofilm Formation in Bacillus cereus.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {13}, pages = {}, pmid = {28432092}, issn = {1098-5336}, mesh = {Bacillus cereus/*genetics/physiology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Gene Expression Profiling ; *Genome, Bacterial ; Mutagenesis, Insertional ; }, abstract = {Bacillus cereus is a soil-dwelling Gram-positive bacterium capable of forming structured multicellular communities, or biofilms. However, the regulatory pathways controlling biofilm formation are less well understood in B. cereus In this work, we developed a method to study B. cereus biofilms formed at the air-liquid interface. We applied two genome-wide approaches, random transposon insertion mutagenesis to identify genes that are potentially important for biofilm formation, and transcriptome analyses by RNA sequencing (RNA-seq) to characterize genes that are differentially expressed in B. cereus when cells were grown in a biofilm-inducing medium. For the first approach, we identified 23 genes whose disruption by transposon insertion led to altered biofilm phenotypes. Based on the predicted function, they included genes involved in processes such as nucleotide biosynthesis, iron salvage, and antibiotic production, as well as genes encoding an ATP-dependent protease and transcription regulators. Transcriptome analyses identified about 500 genes that were differentially expressed in cells grown under biofilm-inducing conditions. One particular set of those genes may contribute to major metabolic shifts, leading to elevated production of small volatile molecules. Selected volatile molecules were shown to stimulate robust biofilm formation in B. cereus Our studies represent a genome-wide investigation of B. cereus biofilm formation.IMPORTANCE In this work, we established a robust method for B. cereus biofilm studies and applied two genome-wide approaches, transposon insertion mutagenesis and transcriptome analyses by RNA-seq, to identify genes and pathways that are potentially important for biofilm formation in B. cereus We discovered dozens of genes and two major metabolic shifts that seem to be important for biofilm formation in B. cereus Our study represents a genome-wide investigation on B. cereus biofilm formation.}, } @article {pmid28430084, year = {2017}, author = {Xu, S and Yang, N and Zheng, S and Yan, F and Jiang, C and Yu, Y and Guo, J and Chai, Y and Chen, Y}, title = {The spo0A-sinI-sinR Regulatory Circuit Plays an Essential Role in Biofilm Formation, Nematicidal Activities, and Plant Protection in Bacillus cereus AR156.}, journal = {Molecular plant-microbe interactions : MPMI}, volume = {30}, number = {8}, pages = {603-619}, doi = {10.1094/MPMI-02-17-0042-R}, pmid = {28430084}, issn = {0894-0282}, mesh = {Amino Acid Sequence ; Animals ; Bacillus cereus/genetics/metabolism/*physiology/ultrastructure ; Bacillus subtilis/genetics/metabolism/ultrastructure ; Bacterial Proteins/chemistry/*metabolism ; Base Sequence ; *Biofilms ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Genetic Association Studies ; Mutation/genetics ; Nematoda/*physiology ; Plant Diseases/genetics/parasitology ; Plant Roots/parasitology ; Spores, Bacterial/physiology ; }, abstract = {The rhizosphere bacterium Bacillus cereus AR156 is capable of forming biofilms, killing nematodes, and protecting plants. However, the underlying molecular mechanisms of these processes are not well understood. In this study, we found that the isogenic mutants ΔBcspo0A and ΔBcsinI have significantly reduced colonization and nematicidal activity in vitro and biological control efficacy on the tomato plant under greenhouse conditions. We further investigated the role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, killing against nematodes, and biological control in AR156. Results from mutagenesis of those regulatory genes in AR156 and their heterologous expression in B. subtilis suggested that the spo0A-sinI-sinR genetic circuit is not only essential for biofilm formation and cell differentiation in AR156 but also able to functionally replace their counterparts in B. subtilis in a nearly indistinguishable fashion. Genome-wide transcriptional profiling in the wild type and the ΔBcspo0A and ΔBcsinI mutants further revealed hundreds of differentially expressed genes, likely positively regulated by both Spo0A and SinI (via SinR) in AR156. Among them, 29 genes are predicted to be directly controlled by SinR, whose counterpart in B. subtilis is a biofilm master repressor. Collectively, our studies demonstrated the essential role of the spo0A-sinI-sinR regulatory circuit in biofilm formation, cell differentiation, and bacteria-host interactions in B. cereus AR156.}, } @article {pmid28429871, year = {2017}, author = {Gupta, P and Sarkar, A and Sandhu, P and Daware, A and Das, MC and Akhter, Y and Bhattacharjee, S}, title = {Potentiation of antibiotic against Pseudomonas aeruginosa biofilm: a study with plumbagin and gentamicin.}, journal = {Journal of applied microbiology}, volume = {123}, number = {1}, pages = {246-261}, doi = {10.1111/jam.13476}, pmid = {28429871}, issn = {1365-2672}, support = {//State Biotech Hub, Tripura University/ ; //University Grants Commission/ ; //Indian Council of Medical Research/ ; //SERB-Department of Science and Technology/ ; }, abstract = {AIMS: Pseudomonas aeruginosa is one of the fatal biofilm-forming pathogens which pose to be a problem in clinical infections, contamination of food and marine ecosystems. In this report, a naphthoquinone-plumbagin has been explored for its antimicrobial (antibacterial and antibiofilm) activity against P. aeruginosa biofilm. The ability of plumbagin to enhance the bioactivity of a known broad-spectrum antibiotic was further assayed by combining the sub-MIC doses of plumbagin with sub-MIC doses of gentamicin against P. aeruginosa biofilm.

METHODS AND RESULTS: This combinatorial approach was used for a series of experiments for understanding the mechanism of action for antibiofilm activity against P. aeruginosa (MTCC 424, MTCC 2488). Antibiofilm activity was studied by safranin staining, estimating total protein, visualization of biofilms and extra polymeric substances quantification. Antivirulent activity of these doses was studied by azocasein degradation, expression of virulent factors and molecular docking. Expression of quorum sensing (QS) phenotypes was studied by motility assessment and mRNA expression pattern of virulence genes. It was observed that plumbagin alone and the combinatorial doses of plumbagin and gentamicin exhibit significant antibiofilm and antivirulent activity coupled with the reduction in the expression of QS phenotypes and virulence genes. Molecular docking study revealed that plumbagin had variable affinity for different QS proteins.

CONCLUSION: Low doses of plumbagin and gentamicin exhibit synergistic activity against P. aeruginosa biofilm while maintaining their effectiveness.

As the P. aeruginosa biofilms are reservoir of persister bacteria, thus, the increasing concern of antibiotic tolerance has to be dealt with combinatorial approaches. In this report, plumbagin has been explored in potentiating the antibiofilm effect of a broad-spectrum antibiotic gentamicin for better therapeutic efficacy.}, } @article {pmid28427132, year = {2017}, author = {Guo, HN and Xiang, J}, title = {[Influences of abaR gene on biofilm formation of Acinetobacter baumannii].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {33}, number = {4}, pages = {200-205}, doi = {10.3760/cma.j.issn.1009-2587.2017.04.003}, pmid = {28427132}, issn = {1009-2587}, mesh = {4-Butyrolactone/analogs & derivatives ; Acinetobacter Infections/drug therapy/*microbiology ; Acinetobacter baumannii/drug effects/*genetics/*isolation & purification ; *Biofilms ; Burns/*microbiology ; China ; Drug Resistance, Bacterial ; Genes, Bacterial ; Humans ; }, abstract = {Objective: To detect drug-resistant phenotype and abaR gene of Acinetobacter baumannii (AB) and investigate influences of abaR gene on biofilm formation of AB. Methods: From February to July 2014, 159 strains AB were collected from Department of Clinical Microbiology of Ruijin Hospital of School of Medicine of Shanghai JiaoTong University and numbered starting from 1 according time when they were collected. (1) The above-mentioned 159 strains of AB were identified by detecting gene sequence of 16S ribosomal DNA. According to results of drug sensitivity test, extensively drug-resistant strains and sensitive strains of AB were selected and counted, and their sources were recorded. (2) Extensively drug-resistant strains and sensitive strains of AB were collected to measure biofilm formation (denoted as absorbance value) by methyl thiazolyl tetrazolium method when strains at culture hour 12, 24, 48 and 72. (3) The abaR gene sequence of ATCC 17978 of AB was analyzed through Gene banks of National Center for Biotechnology Information and compared with AqsR gene sequence of LuxR type receptor of Acinetobacter oleivorans DR1. No. 87 and No. 96 AB strains were amplified and sequenced by polymerase chain reaction according to target gene sequence of abaR of ATCC 17978 of AB. The sequencing result was compared with abaR gene sequence of ATCC 17978. (4) No. 87 and No. 96 AB strains were collected and divided into 0.1% dimethyl sulfoxide (DMSO) group, 10 μmol/L N-heptanoyl-L-Homoserine lactone (C7-HSL) group, 10 μmol/L N-(3-Hydroxydodecanoyl)-DL-homoserine lactone (OH-dDHL) group, 1% DMSO group, 100 μmol/L C7-HSL group, and 100 μmol/L OH-dDHL, with 3 wells of each group. AB strains in the above groups were respectively dealt with DMSO of corresponding final volume fraction, C7-HSL and OH-dDHL of corresponding final amount-of-substance concentration. Biofilm formation (denoted as absorbance value) of AB was measured by methyl thiazolyl tetrazolium method at culture hour 12, 24, 48 and 72. Data were processed with analysis of variance of factorial design, one-way analysis of variance, LSD test and Bonferroni correction. Results: (1) There were 18 extensively drug-resistant strains and 5 sensitive strains of AB. Samples of extensively drug-resistant strains were mainly collected from Emergency ICU and Department of Burns and Plastic Surgery of our hospital and were mainly from sputum, blood, and wound exudate. Samples of sensitive strains were collected dispersedly and were mainly from sputum. (2) Absorbance values of extensively drug-resistant strains and sensitive strains of AB at all culture time points were similar (with P values above 0.05). Absorbance value of extensively drug-resistant strains of AB at culture hour 24 was obviously higher than that of these strains at culture hour 12, 48, or 72 (with P values below 0.01). Absorbance value of sensitive strains of AB at culture hour 24 was obviously higher than that of these strains at culture hour 12 (P<0.01). (3) AbaR gene sequence of LuxR type receptor existed in AB. Similarity ratio between abaR gene sequence and LuxR type receptor AqsR gene sequence in Acinetobacter oleivorans DR1 was 87%. Similarity ratios between abaR gene sequence of No. 87 and No. 96 strains and ATCC 17978 of AB were 98% and 99%, respectively. (4) Absorbance values of 0.1% DMSO group of No. 87 strain at all culture time points were similar to those of 1% DMSO group (with P values above 0.05). Absorbance value of 0.1% DMSO group of No. 96 strain at culture hour 12 was obviously lower than that of 1% DMSO group (P<0.01), while that at culture hour 24 was obviously lower than that of 1% DMSO group (P<0.01). Absorbance values of 10 μmol/L C7-HSL group of No. 87 and No. 96 strains at culture hour 24 were obviously lower than those of 0.1% DMSO group (with P values below 0.01). Absorbance values of 100 μmol/L C7-HSL group of No. 87 strain at all culture time points were similar to those of 1% DMSO group, respectively (with P values above 0.05). Absorbance value of 100 μmol/L C7-HSL group of No. 96 strain at culture hour 12 was lower than that of 1% DMSO group (P<0.01). Absorbance values of 10 μmol/L OH-dDHL group of No. 87 and No. 96 strains were similar to those of 0.1% DMSO group (with P values above 0.05). Absorbance values of 100 μmol/L OH-dDHL group of No. 87 strain at all culture time points were similar to those of 1% DMSO group (with P values above 0.05). Absorbance value of 100 μmol/L OH-dDHL group of No. 96 strain at culture hour 12 was obviously higher than that of 1% DMSO group (P<0.01). Absorbance values of 0.1% DMSO group and 1% DMSO group of No. 87 and No. 96 strains at culture hour 24 were obviously higher than those at culture hour 12 and 48 (with P values below 0.01). Conclusions: Extensively drug-resistant strains of AB exist commonly. AbaR gene exists in AB has relation with biofilm formation of AB.}, } @article {pmid28426329, year = {2017}, author = {Ali, Q and Wahl, LM}, title = {Mathematical modelling of CRISPR-Cas system effects on biofilm formation.}, journal = {Journal of biological dynamics}, volume = {11}, number = {sup2}, pages = {264-284}, doi = {10.1080/17513758.2017.1314025}, pmid = {28426329}, issn = {1751-3766}, mesh = {Bacteria/*virology ; Bacteriophages/*physiology ; Biofilms/*growth & development ; CRISPR-Associated Proteins ; *CRISPR-Cas Systems ; Clustered Regularly Interspaced Short Palindromic Repeats ; *Models, Biological ; }, abstract = {Clustered regularly interspaced short palindromic repeats (CRISPR), linked with CRISPR associated (Cas) genes, can confer adaptive immunity to bacteria, against bacteriophage infections. Thus from a therapeutic standpoint, CRISPR immunity increases biofilm resistance to phage therapy. Recently, however, CRISPR-Cas genes have been implicated in reducing biofilm formation in lysogenized cells. Thus CRISPR immunity can have complex effects on phage-host-lysogen interactions, particularly in a biofilm. In this contribution, we develop and analyse a series of dynamical systems to elucidate and disentangle these interactions. Two competition models are used to study the effects of lysogens (first model) and CRISPR-immune bacteria (second model) in the biofilm. In the third model, the effect of delivering lysogens to a CRISPR-immune biofilm is investigated. Using standard analyses of equilibria, stability and bifurcations, our models predict that lysogens may be able to displace CRISPR-immune bacteria in a biofilm, and thus suggest strategies to eliminate phage-resistant biofilms.}, } @article {pmid28426246, year = {2017}, author = {Kilic, T and Karaca, B and Ozel, BP and Ozcan, B and Cokmus, C and Coleri Cihan, A}, title = {Biofilm characteristics and evaluation of the sanitation procedures of thermophilic Aeribacillus pallidus E334 biofilms.}, journal = {Biofouling}, volume = {33}, number = {4}, pages = {352-367}, doi = {10.1080/08927014.2017.1313412}, pmid = {28426246}, issn = {1029-2454}, mesh = {Bacillaceae/drug effects/genetics/*growth & development/physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Biomass ; DNA, Bacterial ; Disinfectants/*pharmacology ; Hot Temperature ; Hydrogen-Ion Concentration ; Sanitation/*methods ; Surface Properties ; }, abstract = {The ability of Aeribacillus pallidus E334 to produce pellicle and form a biofilm was studied. Optimal biofilm formation occurred at 60 °C, pH 7.5 and 1.5% NaCl. Extra polymeric substances (EPS) were composed of proteins and eDNA (21.4 kb). E334 formed biofilm on many surfaces, but mostly preferred polypropylene and glass. Using CLSM analysis, the network-like structure of the EPS was observed. The A. pallidus biofilm had a novel eDNA content. DNaseI susceptibility (86.8% removal) of eDNA revealed its importance in mature biofilms, but the purified eDNA was resistant to DNaseI, probably due to its extended folding outside the matrix. Among 15 cleaning agents, biofilms could be removed with alkaline protease and sodium dodecyl sulphate (SDS). The removal of cells from polypropylene and biomass on glass was achieved with combined SDS/alkaline protease treatment. Strong A. pallidus biofilms could cause risks for industrial processes and abiotic surfaces must be taken into consideration in terms of sanitation procedures.}, } @article {pmid28422332, year = {2017}, author = {Guilhen, C and Forestier, C and Balestrino, D}, title = {Biofilm dispersal: multiple elaborate strategies for dissemination of bacteria with unique properties.}, journal = {Molecular microbiology}, volume = {105}, number = {2}, pages = {188-210}, doi = {10.1111/mmi.13698}, pmid = {28422332}, issn = {1365-2958}, mesh = {Bacteria/growth & development/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/genetics ; }, abstract = {In most environments, microorganisms evolve in a sessile mode of growth, designated as biofilm, which is characterized by cells embedded in a self-produced extracellular matrix. Although a biofilm is commonly described as a "cozy house" where resident bacteria are protected from aggression, bacteria are able to break their biofilm bonds and escape to colonize new environments. This regulated process is observed in a wide variety of species; it is referred to as biofilm dispersal, and is triggered in response to various environmental and biological signals. The first part of this review reports the main regulatory mechanisms and effectors involved in biofilm dispersal. There is some evidence that dispersal is a necessary step between the persistence of bacteria inside biofilm and their dissemination. In the second part, an overview of the main methods used so far to study the dispersal process and to harvest dispersed bacteria was provided. Then focus was on the properties of the biofilm-dispersed bacteria and the fundamental role of the dispersal process in pathogen dissemination within a host organism. In light of the current body of knowledge, it was suggested that dispersal acts as a potent means of disseminating bacteria with enhanced colonization properties in the surrounding environment.}, } @article {pmid28422057, year = {2017}, author = {Millot, M and Girardot, M and Dutreix, L and Mambu, L and Imbert, C}, title = {Antifungal and Anti-Biofilm Activities of Acetone Lichen Extracts against Candida albicans.}, journal = {Molecules (Basel, Switzerland)}, volume = {22}, number = {4}, pages = {}, pmid = {28422057}, issn = {1420-3049}, mesh = {Acetone ; Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/*growth & development ; Inhibitory Concentration 50 ; Lichens/*chemistry ; Microbial Sensitivity Tests ; Phytochemicals ; Plant Extracts/chemistry/*pharmacology ; }, abstract = {Candida albicans is a commensal coloniser of the human gastrointestinal tract and an opportunistic pathogen, especially thanks to its capacity to form biofilms. This lifestyle is frequently involved in infections and increases the yeast resistance to antimicrobials and immune defenses. In this context, 38 lichen acetone extracts have been prepared and evaluated for their activity against C. albicans planktonic and sessile cells. Minimum inhibitory concentrations of extracts (MICs) were determined using the broth microdilution method. Anti-biofilm activity was evaluated using tetrazolium salt (XTT) assay as the ability to inhibit the maturation phase (anti-maturation) or to eradicate a preformed 24 h old biofilm (anti-biofilm). While none of the extracts were active against planktonic cells, biofilm maturation was limited by 11 of the tested extracts. Seven extracts displayed both anti-maturation and anti-biofilm activities (half maximal inhibitory concentrations IC50_mat and IC50_biof ≤ 100 µg/mL); Evernia prunastri and Ramalina fastigiata were the most promising lichens (IC50_mat < 4 µg/mL and IC50_biof < 10 µg/mL). Chemical profiles of the active extracts performed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) have been analyzed. Depsides, which were present in large amounts in the most active extracts, could be involved in anti-biofilm activities. This work confirmed that lichens represent a reservoir of compounds with anti-biofilm potential.}, } @article {pmid28421562, year = {2017}, author = {El-Ganiny, AM and Shaker, GH and Aboelazm, AA and El-Dash, HA}, title = {Prevention of Bacterial Biofilm Formation on Soft Contact Lenses Using Natural Compounds.}, journal = {Journal of ophthalmic inflammation and infection}, volume = {7}, number = {1}, pages = {11}, pmid = {28421562}, issn = {1869-5760}, abstract = {PURPOSE: In eye care field, contact lenses (CL) have a great impact on improving vision, but their use can be limited by ocular infection. CL- associated infections can be reduced by good attention to CL storage case practice. CL-care solutions should be able to control microbial growth on CL. The aim of the study was to evaluate and compare the efficacy of CL-care solutions (found in Egyptian market) with some natural compounds in removal and inhibition of bacterial biofilm formed on soft CL. Clinical isolates were recovered from patients having conjunctivitis from Benha University Hospital and identified microbiologically. Quantification of biofilm was done using microtiter plate assay. Three multipurpose CL-care solutions were examined for their ability to remove and inhibit biofilm. Also four natural extracts having antibacterial activity and are safe on eye were tested for their anti-biofilm activity.

RESULTS: The major bacterial isolates from eye infections were Pseudomonas aeruginosa (36%) and Staphylococcus spp. (37.8%). Only 33.3% of isolates showed ability to produce weak to moderate biofilm. The tested multi-purpose CL-care solutions showed moderate ability to remove preformed biofilm. Among the tested natural compounds, Calendula officinalis and Buddleja salviifolia extracts showed an excellent efficacy in inhibition of biofilm and also removal of preformed biofilm.

CONCLUSION: This study demonstrated that isolates from infected eye and CL-cases showed weak to moderate biofilm formation. Calendula officinalis and Buddleja salviifolia extracts showed excellent effect on inhibition and removal of biofilm, these extracts could be added into CL-care solutions which could markedly reduce eye-infections during CL-wear.}, } @article {pmid28420074, year = {2017}, author = {Brouse, L and Brouse, R and Brouse, D}, title = {Natural Pathogen Control Chemistry to Replace Toxic Treatment of Microbes and Biofilm in Cooling Towers.}, journal = {Pathogens (Basel, Switzerland)}, volume = {6}, number = {2}, pages = {}, pmid = {28420074}, issn = {2076-0817}, abstract = {Application of toxic antibacterial agents is considered necessary to control prevalent fresh water microorganisms that grow in evaporative cooling water systems, but can adversely affect the environment and human health. However, natural antibacterial water chemistry has been applied in industrial cooling water systems for over 10 years to inhibit microorganisms with excellent results. The water chemistry method concentrates natural minerals in highly-softened water to produce elevated pH and dissolved solids, while maintaining low calcium and magnesium content. The method provides further benefits in water conservation, and generates a small volume of non-toxic natural salt concentrate for cost efficient separation and disposal if required. This report describes the antimicrobial effects of these chemistry modifications in the cooling water environment and the resultant collective inhibition of microbes, biofilm, and pathogen growth. This article also presents a novel perspective of parasitic microbiome functional relationships, including "Trojan Protozoans" and biofilms, and the function of polyvalent metal ions in the formation and inhibition of biofilms. Reducing global dependence on toxic antibacterial agents discharged to the environment is an emerging concern due to their impact on the natural microbiome, plants, animals and humans. Concurrently, scientists have concluded that discharge of antibacterial agents plays a key role in development of pathogen resistance to antimicrobials as well as antibiotics. Use of natural antibacterial chemistry can play a key role in managing the cooling water environment in a more ecologically sustainable manner.}, } @article {pmid28419759, year = {2017}, author = {Fazli, M and Rybtke, M and Steiner, E and Weidel, E and Berthelsen, J and Groizeleau, J and Bin, W and Zhi, BZ and Yaming, Z and Kaever, V and Givskov, M and Hartmann, RW and Eberl, L and Tolker-Nielsen, T}, title = {Regulation of Burkholderia cenocepacia biofilm formation by RpoN and the c-di-GMP effector BerB.}, journal = {MicrobiologyOpen}, volume = {6}, number = {4}, pages = {}, pmid = {28419759}, issn = {2045-8827}, mesh = {Biofilms/*growth & development ; Burkholderia cenocepacia/genetics/growth & development/metabolism/*physiology ; Cyclic GMP/*analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Polysaccharides, Bacterial/metabolism ; Sigma Factor/genetics/*metabolism ; Transcription Factors/genetics/*metabolism ; }, abstract = {Knowledge about the molecular mechanisms that are involved in the regulation of biofilm formation is essential for the development of biofilm-control measures. It is well established that the nucleotide second messenger cyclic diguanosine monophosphate (c-di-GMP) is a positive regulator of biofilm formation in many bacteria, but more knowledge about c-di-GMP effectors is needed. We provide evidence that c-di-GMP, the alternative sigma factor RpoN (σ54), and the enhancer-binding protein BerB play a role in biofilm formation of Burkholderia cenocepacia by regulating the production of a biofilm-stabilizing exopolysaccharide. Our findings suggest that BerB binds c-di-GMP, and activates RpoN-dependent transcription of the berA gene coding for a c-di-GMP-responsive transcriptional regulator. An increased level of the BerA protein in turn induces the production of biofilm-stabilizing exopolysaccharide in response to high c-di-GMP levels. Our findings imply that the production of biofilm exopolysaccharide in B. cenocepacia is regulated through a cascade involving two consecutive transcription events that are both activated by c-di-GMP. This type of regulation may allow tight control of the expenditure of cellular resources.}, } @article {pmid28419339, year = {2017}, author = {Maharjan, P and Dey, S and Huff, G and Zhang, W and Phillips, GK and Watkins, S}, title = {Effect of chlorine treatment on inhibition of E. coli serogroup O2 incorporation into 7-day-old biofilm on polyvinylchloride surface.}, journal = {Poultry science}, volume = {96}, number = {8}, pages = {2862-2870}, doi = {10.3382/ps/pex088}, pmid = {28419339}, issn = {1525-3171}, mesh = {Animal Husbandry ; Animals ; Biofilms/*drug effects ; Chickens ; Chlorine/*pharmacology ; Disinfectants/*pharmacology ; Escherichia coli/*drug effects/*physiology ; Hot Temperature ; Housing, Animal ; *Water Microbiology ; Water Movements ; *Water Supply ; }, abstract = {Poultry waterlines are constructed using polyvinylchloride (PVC) material on which bacterial biofilm can easily form. Biofilm can harbor pathogens including avian pathogenic E. coli (APEC) strains. An in vitro evaluation was performed to determine if E. coli sero group O2 (avian pathogenic) could attach on a PVC surface that had pre-formed biofilm and if this phenomenon could be affected when water was treated with chlorine. Initially, biofilm growth was induced in PVC test coupons (15.16 cm2) for a 7-day period mimicking the waterline scenario in the first wk of poultry brooding; and then this biofilm was challenged with E. coli O2 seeded water in presence/absence of chlorine treatment. After rinsing, test coupons were sampled for bacterial (APC) and E. coli O2 enumeration at various occasions post seeding the pathogen and chlorine treatment. Day 7 APC recovered from coupons was 4.35 log10 cfu/cm2 in trial 1 and 3.66 log10 cfu/cm2 in trial 2. E. coli O2 was not recovered from chlorine treated test coupons (P < 0.05), whereas it was retrieved from untreated coupons (untreated contained > 3 log10 cfu/cm2 in trial 1 and > 2 log10 cfu/cm2 in trial 2). This study suggests that E. coli O2 can incorporate into pre-formed biofilm on a PVC surface within 24 h if water sanitation is not present, and the attachment time of the pathogen can prolong in the absence of already formed biofilm.}, } @article {pmid28418636, year = {2017}, author = {Carey, PR and Gibson, BR and Gibson, JF and Greenberg, ME and Heidari-Torkabadi, H and Pusztai-Carey, M and Weaver, ST and Whitmer, GR}, title = {Defining Molecular Details of the Chemistry of Biofilm Formation by Raman Microspectroscopy.}, journal = {Biochemistry}, volume = {56}, number = {17}, pages = {2247-2250}, doi = {10.1021/acs.biochem.7b00116}, pmid = {28418636}, issn = {1520-4995}, mesh = {Analytic Sample Preparation Methods ; Bacterial Proteins/biosynthesis/chemistry/isolation & purification ; *Biofilms/growth & development ; Carbohydrates/biosynthesis/isolation & purification ; Escherichia coli K12/chemistry/cytology/growth & development/*physiology ; Freeze Drying ; Microtechnology ; Plankton/growth & development/*physiology ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; RNA, Bacterial/biosynthesis/isolation & purification ; Reproducibility of Results ; Spectrum Analysis, Raman ; Staphylococcus epidermidis/chemistry/cytology/growth & development/*physiology ; }, abstract = {Two protocols that allow for the comparison of Raman spectra of planktonic cells and biofilm formed from these cells in their growth phase have been developed. Planktonic cells are washed and flash-frozen in <1 min to reduce the time for metabolic changes during processing, prior to freeze-drying. Biofilm is formed by standing cells in 50 μL indentations in aluminum foil in an atmosphere of saturated water vapor for 24-48 h. The results for Escherichia coli type K12 cells, which do not readily form biofilm, are compared to those for Staphylococcus epidermidis cells, which prolifically synthesize biofilm. For E. coli, the Raman spectra of the planktonic and biofilm samples are similar with the exception that the spectral signature of RNA, present in planktonic cells, could not be detected in biofilm. For S. epidermidis, major changes occur upon biofilm formation. In addition to the absence of the RNA features, new bands occur near 950 cm[-1] and between 1350 and 1420 cm[-1] that are associated with an increase in carbohydrate content. Unlike the case in E. coli biofilm, the intensity of G base ring modes is reduced in but A and T base ring signatures become more prominent. For S. epidermis in the biofilm's amide III region, there is evidence of an increase in the level of β-sheet structure accompanied by a decrease in α-helical content. The presence of biofilm is confirmed by microscope-aided photography and, separately, by staining with methyl violet.}, } @article {pmid28418126, year = {2017}, author = {Stoodley, P}, title = {Evidence for a biofilm-based treatment strategy in the management of chronic hidradenitis suppurativa.}, journal = {The British journal of dermatology}, volume = {176}, number = {4}, pages = {855-856}, doi = {10.1111/bjd.15256}, pmid = {28418126}, issn = {1365-2133}, mesh = {*Biofilms ; *Hidradenitis Suppurativa ; Humans ; }, } @article {pmid28418081, year = {2017}, author = {Shafique, M and Alvi, IA and Abbas, Z and Ur Rehman, S}, title = {Assessment of biofilm removal capacity of a broad host range bacteriophage JHP against Pseudomonas aeruginosa.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {6}, pages = {579-584}, doi = {10.1111/apm.12691}, pmid = {28418081}, issn = {1600-0463}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Host Specificity ; Microbial Viability ; Pseudomonas Phages/growth & development/*physiology ; Pseudomonas aeruginosa/growth & development/*physiology/*virology ; }, abstract = {Pseudomonas aeruginosa is an efficient biofilm-dwelling microbial pathogen, associated with nosocomial infections. These biofilm-associated infections are resistant to antibiotics and immune defenses, therefore pose major problem against their treatment. This scenario demands alternative therapeutic regimens, and bacteriophage therapy is one among potential strategies for clinical management of multiple drug resistance. In this investigation, the efficacy of a bacteriophage, JHP, is evaluated to eradicate P. aeruginosa biofilms. Growth kinetics of P. aeruginosa biofilm revealed that the highest cell density biofilm (1.5 × 10[16] CFU/mL) was established within the polystyrene microtiter plate at 72 h post inoculation. Pseudomonas aeruginosa biofilms of different ages, treated with JHP (0.6 MOI) for different post-infection durations, reduced biomass from 2 to 4.5 logs (60-90%). JHP treatment before biofilm development reduced the bacterial load up to 9 logs (>95% bacterial load reduction) as compared with untreated control, which highlights its potential to prevent biofilm formation in indwelling medical devices. Combinations of JHP with other phages or antibiotics could be an efficient alternative for P. aeruginosa biofilm removal in clinical and industrial settings.}, } @article {pmid28417271, year = {2017}, author = {Piotrowski, M and Karpiński, P and Pituch, H and van Belkum, A and Obuch-Woszczatyński, P}, title = {Antimicrobial effects of Manuka honey on in vitro biofilm formation by Clostridium difficile.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {36}, number = {9}, pages = {1661-1664}, pmid = {28417271}, issn = {1435-4373}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Clostridioides difficile/*drug effects/genetics/*growth & development/isolation & purification ; *Honey ; Humans ; Microbial Sensitivity Tests ; Molecular Typing ; }, abstract = {Clostridium difficile is the cause of the nosocomial C. difficile infection (CDI). The conventional antibiotics used in CDI therapy are often unsuccessful, and recurrent infections may occur. Biofilm formation by C. difficile is associated with chronic or recurrent infections; biofilms may contribute to virulence and impaired antimicrobial efficacy. Manuka honey, derived from the Manuka tree (Leptospermum scoparium), is known to exhibit antimicrobial properties that are associated with its significant content of methylglyoxal, a natural antibiotic. The aim of the present study was to determine the antimicrobial effect of Manuka honey on clinical C. difficile strains belonging to four prominent polymerase chain reaction (PCR) ribotypes (RTs) (RT017, RT023, RT027 and RT046) and on their biofilm formation in vitro. Minimal inhibitory and bactericidal concentrations (MICs and MBCs, respectively) were determined using the broth dilution method. The biomass of the biofilm and the clearance of C. difficile biofilms by Manuka honey were determined using the crystal violet staining method. The MIC and MBC of Manuka honey for C. difficile strains were equal at 6.25% (v/v). PCR RT027 strains produced more biofilm in vitro than the other examined strains. Manuka honey effectively inhibited biofilm formation by C. difficile strains of different PCR RTs.}, } @article {pmid28416302, year = {2017}, author = {Vishwanat, L and Duong, R and Takimoto, K and Phillips, L and Espitia, CO and Diogenes, A and Ruparel, SB and Kolodrubetz, D and Ruparel, NB}, title = {Effect of Bacterial Biofilm on the Osteogenic Differentiation of Stem Cells of Apical Papilla.}, journal = {Journal of endodontics}, volume = {43}, number = {6}, pages = {916-922}, doi = {10.1016/j.joen.2017.01.023}, pmid = {28416302}, issn = {1878-3554}, mesh = {Alkaline Phosphatase/metabolism ; *Biofilms ; Cell Differentiation/physiology ; Dental Papilla/*cytology/growth & development/microbiology ; Dental Pulp Cavity/microbiology ; Enterococcus faecalis ; Humans ; *Osteogenesis/physiology ; Stem Cells/*physiology ; Transcriptome ; }, abstract = {INTRODUCTION: Although clinical success in regenerative endodontics is substantially high, histological success is limited to finding bone/cementum-like tissue instead of dentin within the canal space. The aims of this study were to investigate (1) the effect of bacterial biofilm on osteogenic gene expression in stem cells of the apical papilla (SCAP) and (2) the effect of bacterial antigens on the functional differentiation of SCAP into a mineralizing phenotype.

METHODS: Using an ex vivo organotypic root canal model and an American Association of Endontists-recommended regenerative endodontic procedures, we evaluated SCAP differentiation in the presence and absence of an Enterococcus faecalis biofilm. Gene expression analysis for dentinogenic and osteoblastic markers was performed with real-time polymerase chain reaction. The effect of E. faecalis antigens on SCAP differentiation into mineralizing cells in vitro was evaluated with 2 functional assays: Alizarin Red and alkaline phosphatase activity assays.

RESULTS: After regenerative endodontic procedures, residual bacteria continued to sustain within the root canal system. SCAP in the presence of E. faecalis biofilm significantly downregulated dentinogenic genes such as dentin sialophosphoprotein and upregulated osteoblastic genes such as bone sialoprotein, osteocalcin, distal-less homeobox 5, and runt-related transcription factor 2. E. faecalis antigens significantly inhibited SCAP differentiation into a mineralizing phenotype when alizarin red staining and alkaline phosphatase assays were used in vitro.

CONCLUSIONS: Current disinfection protocols were ineffective in eliminating bacteria from root tips and the levels of the residual bacterial biofilm, and its byproducts, were able to significantly alter osteogenic-differentiation of SCAP.}, } @article {pmid28416278, year = {2017}, author = {Ma, R and Qiu, S and Jiang, Q and Sun, H and Xue, T and Cai, G and Sun, B}, title = {AI-2 quorum sensing negatively regulates rbf expression and biofilm formation in Staphylococcus aureus.}, journal = {International journal of medical microbiology : IJMM}, volume = {307}, number = {4-5}, pages = {257-267}, doi = {10.1016/j.ijmm.2017.03.003}, pmid = {28416278}, issn = {1618-0607}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Carbon-Sulfur Lyases/genetics ; *Gene Expression Regulation, Bacterial ; Homoserine/*analogs & derivatives/pharmacology ; Lactones/*pharmacology ; Pentanes/metabolism ; Polysaccharides, Bacterial/genetics/metabolism ; Promoter Regions, Genetic ; Quorum Sensing/*drug effects ; Staphylococcus aureus/*genetics ; beta-Galactosidase/genetics/metabolism ; }, abstract = {Staphylococcus aureus is an important pathogen that is capable of forming biofilms on biomaterial surfaces to cause biofilm-associated infections. Autoinducer 2 (AI-2), a universal language for interspecies communication, is involved in a variety of physiological activities, although its exact role in Gram-positive bacteria, especially in S. aureus, is not yet thoroughly characterized. Herein we demonstrate that inactivation of luxS, which encodes AI-2 synthase, resulted in increased biofilm formation and higher polysaccharide intercellular adhesion (PIA) production compared with the wild-type strain in S. aureus NCTC8325. The transcript level of rbf, a positive regulator of biofilm formation, was significantly increased in the luxS mutant. All of the parental phenotypes could be restored by genetic complementation and chemically synthesized 4,5-dihydroxy-2,3-pentanedione, the AI-2 precursor molecule, suggesting that AI-2 has a signaling function to regulate rbf transcription and biofilm formation in S. aureus. Phenotypic analysis revealed that the luxS rbf double mutant produced approximately the same amount of biofilms and PIA as the rbf mutant. In addition, real-time quantitative reverse transcription-PCR analysis showed that the icaA transcript level of the rbf mutant was similar to that of the luxS rbf double mutant. These findings demonstrate that the LuxS/AI-2 system regulates PIA-dependent biofilm formation via repression of rbf expression in S. aureus. Furthermore, we demonstrated that Rbf could bind to the sarX and rbf promoters to upregulate their expression.}, } @article {pmid28414173, year = {2017}, author = {Cyphert, EL and Zuckerman, ST and Korley, JN and von Recum, HA}, title = {Affinity interactions drive post-implantation drug filling, even in the presence of bacterial biofilm.}, journal = {Acta biomaterialia}, volume = {57}, number = {}, pages = {95-102}, pmid = {28414173}, issn = {1878-7568}, support = {R43 GM100525/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*chemistry ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*chemistry ; Drug Delivery Systems/*methods ; Humans ; Organ Transplantation ; }, abstract = {UNLABELLED: Current post-operative standard of care for surgical procedures, including device implantations, dictates prophylactic antimicrobial therapy, but a percentage of patients still develop infections. Systemic antimicrobial therapy needed to treat such infections can lead to downstream tissue toxicities and generate drug-resistant bacteria. To overcome issues associated with systemic drug administration, a polymer incorporating specific drug affinity has been developed with the potential to be filled or refilled with antimicrobials, post-implantation, even in the presence of bacterial biofilm. This polymer can be used as an implant coating or stand-alone drug delivery device, and can be translated to a variety of applications, such as implanted or indwelling medical devices, and/or surgical site infections. The filling of empty affinity-based drug delivery polymer was analyzed in an in vitro filling/refilling model mimicking post-implantation tissue conditions. Filling in the absence of bacteria was compared to filling in the presence of bacterial biofilms of varying maturity to demonstrate proof-of-concept necessary prior to in vivo experiments. Antibiotic filling into biofilm-coated affinity polymers was comparable to drug filling seen in same affinity polymers without biofilm demonstrating that affinity polymers retain ability to fill with antibiotic even in the presence of biofilm. Additionally, post-implantation filled antibiotics showed sustained bactericidal activity in a zone of inhibition assay demonstrating post-implantation capacity to deliver filled antibiotics in a timeframe necessary to eradicate bacteria in biofilms. This work shows affinity polymers can fill high levels of antibiotics post-implantation independent of biofilm presence potentially enabling device rescue, rather than removal, in case of infection.

STATEMENT OF SIGNIFICANCE: Post-operative prophylactic antimicrobial therapy greatly reduces risk of infection, such as on biomedical implants, but does not totally eliminate infections, and the healthcare cost of these remaining infections remains a major concern. Systemic antimicrobial therapy to treat these infections can lead to tissue toxicity and drug-resistant bacteria. In order to treat only those patients who have developed infections, a customizable antimicrobial delivery system made of cyclodextrin-based affinity polymer has been developed that is capable of filling post-implantation and delivering the filled antibiotic in a sustained manner even when the delivery device covered in bacterial biofilm. These observations have the potential to be translated to a wide variety of applications, such as implanted or indwelling medical devices, and/or surgical site infections.}, } @article {pmid28414038, year = {2017}, author = {Gowrishankar, S and Pandian, SK}, title = {Modulation of Staphylococcus epidermidis (RP62A) extracellular polymeric layer by marine cyclic dipeptide-cyclo(l-leucyl-l-prolyl) thwarts biofilm formation.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1859}, number = {7}, pages = {1254-1262}, doi = {10.1016/j.bbamem.2017.04.009}, pmid = {28414038}, issn = {0005-2736}, mesh = {*Biofilms ; Dipeptides/*pharmacology ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Peptides, Cyclic/*pharmacology ; Photoelectron Spectroscopy ; Polymers/*metabolism ; Staphylococcus epidermidis/*drug effects/metabolism ; }, abstract = {Staphylococcus epidermidis is the most frequent cause of biofilm mediated implant-associated infections. Extracellular polymeric substance (EPS) is a key component of most biofilms and in pathogens it specifically protects the entrenched-bacterial cells from antibiotics and hosts immune response, and thereby makes the infection ineradicable. Recently, the prominence of cyclic dipeptides in interfering with biofilms and the associated virulence factors of pathogens has offered an alternative to eliminate difficult-to-treat infections. Therefore, we assessed the effect of a potent antibiofilm agent cyclic dipeptide, cyclo(l-leucyl-l-prolyl) (CLP), on the EPS modification of S. epidermidis. The non-bactericidal antibiofilm efficacy of CLP against S. epidermidis was affirmed through quantitative (crystal violet and XTT assays) and qualitative (confocal and scanning electron microscopes) analyses. Notably, CLP was potent enough to reduce all the EPS components viz. polysaccharides, proteins and eDNA to a significant level. Substantial difference in the atomic composition and functionality of CLP treated EPS was evident through X-ray photoelectron spectroscopy. Furthermore, CLP dehydrated the S. epidermidis-EPS and altered the acetylated sugars as well as α-glycosidic linkage in it. The results of cyclic voltammetry (CV) indicate the decrease of total negative charge of EPS upon CLP treatment, which goes well in accordance with the decrease of eDNA. Thus, antibiofilm efficacy of CLP lies in its potency to alter the intrinsic functional groups and charge of secreted EPS.}, } @article {pmid28413476, year = {2017}, author = {Zhu, C and Bao, NR and Chen, S and Zhao, JN}, title = {The mechanism of human β-defensin 3 in MRSA-induced infection of implant drug-resistant bacteria biofilm in the mouse tibial bone marrow.}, journal = {Experimental and therapeutic medicine}, volume = {13}, number = {4}, pages = {1347-1352}, pmid = {28413476}, issn = {1792-0981}, abstract = {The mechanism of human β-defensin 3 (HBD-3) in methicillin-resistant Staphylococcus aureus (MRSA-induced infection of implant drug-resistant bacteria biofilm in the mouse tibial bone marrow was studied. Healthy adult male Sprague-Dawley rats with average weight of 230 g were selected to construct the infection model of MRSA-induced implant drug-resistant bacteria biofilm in the mouse left tibial bone marrow. The drugs were intraperitoneally injected after 24 h medullary cavity infection, and the experimental groups included the model group, HBD-3 group, and vancomycin group (20 rats in each group). The model group was injected with 10 ml saline, HBD-3 group was injected with 10 ml of 8 µg/ml (1 MIC) and vancomycin group was injected with 10 ml of 0.5 µg/ml (1 MIC), five animals in each group were sacrificed on the 1, 7, 14 and 21 days, respectively. Observation was carried out on whether there was swelling and purulent secretion on the local wound; 1 ml venous sinus blood of eye socket was collected for blood routine examination and blood culture, and the laser scanning confocal microscopy was used to observe the morphology of the biofilm on the implant surface and the number of viable bacteria. Immunohistochemical staining was adopted to test the expression of nuclear factor-κB (NF-κB) and toll-like receptor 4 (TLR-4), and ELISA method was used to test interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), IL-1α and interferon-γ (INF-γ)-inducible protein-10 (IP-10) expression levels. There was no death due to infection in the HBD-3 group or vancomycin group, 1 case with significant wound swelling was found, respectively, in each group, but there was no purulent secretion. The percentage of the total white blood cells and neutrophil granulocytes as well as the biofilm morphology and the number of viable bacteria in the model group was gradually increased with time, while those in the HBD-3 group and vancomycin group were decreased with time. The comparative difference among groups was statistically significant (P<0.05); those in the HBD-3 group and vancomycin group at each time-point was decreased significantly compared with the model group, and the difference among groups was statistically significant (P<0.05), but in terms of the comparison between the HBD-3 group and vancomycin group, the difference was not significantly different (P>0.05). The NF-κB and TLR-4 expressions in the model group and vancomycin group were not significantly changed at each time-point, those in the HBD-3 group began to increase on the 1st day, and reached the peak on the 7th day and began to decline on the 14th day, and the comparative difference at each time-point was statistically significant (P<0.05); those in the HBD-3 group were significantly higher than the model group and vancomycin group at each time-point and the difference was statistically significant (P<0.05). The IL-10, TNF-α, IL-1α, and IP-10 expressions in the model group at each time were significantly higher than the other two groups and the difference was statistically significant (P<0.05); in terms of the comparison between the HBD-3 group and vancomycin group, the difference was not statistically significant (P>0.05). In conclusion, β-defensin 3 can inhibit the bacterial growth by regulating inflammation and immune responses in the MRSA-induced implant drug-resistant bacteria biofilm infection in the mouse tibial bone marrow.}, } @article {pmid28411060, year = {2017}, author = {Costa Silva, RA and da Silva, CR and de Andrade Neto, JB and da Silva, AR and Campos, RS and Sampaio, LS and do Nascimento, FBSA and da Silva Gaspar, B and da Cruz Fonseca, SG and Josino, MAA and Grangeiro, TB and Gaspar, DM and de Lucena, DF and de Moraes, MO and Cavalcanti, BC and Nobre Júnior, HV}, title = {In vitro anti-Candida activity of selective serotonin reuptake inhibitors against fluconazole-resistant strains and their activity against biofilm-forming isolates.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {341-348}, doi = {10.1016/j.micpath.2017.04.008}, pmid = {28411060}, issn = {1096-1208}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Apoptosis/drug effects ; Biofilms/*drug effects/growth & development ; Candida/cytology/*drug effects/genetics/growth & development ; Cell Count ; Cell Death/drug effects ; Cell Line ; Cell Proliferation/drug effects ; DNA Damage/drug effects ; DNA, Fungal/drug effects ; Drug Resistance, Fungal/*drug effects ; Fibroblasts/microbiology ; Flow Cytometry ; Fluconazole/*pharmacology ; In Vitro Techniques ; Membrane Potentials ; Mice ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Mitochondrial Membranes/drug effects ; Paroxetine/pharmacology ; Plasma/drug effects ; Selective Serotonin Reuptake Inhibitors/administration & dosage/*pharmacology ; Sertraline/pharmacology ; }, abstract = {Recent research has shown broad antifungal activity of the classic antidepressants selective serotonin reuptake inhibitors (SSRIs). This fact, combined with the increased cross-resistance frequency of the genre Candida regarding the main treatment today, fluconazole, requires the development of novel therapeutic strategies. In that context, this study aimed to assess the antifungal potential of fluoxetine, sertraline, and paroxetine against fluconazole-resistant Candida spp. planktonic cells, as well as to assess the mechanism of action and the viability of biofilms treated with fluoxetine. After 24 h, the fluconazole-resistant Candida spp. strains showed minimum inhibitory concentration (MIC) in the ranges of 20-160 μg/mL for fluoxetine, 10-20 μg/mL for sertraline, and 10-100.8 μg/mL for paroxetine by the broth microdilution method (M27-A3). According to our data by flow cytometry, each of the SSRIs cause fungal death after damaging the plasma and mitochondrial membrane, which activates apoptotic signaling pathways and leads to dose-dependant cell viability loss. Regarding biofilm-forming isolates, the fluoxetine reduce mature biofilm of all the species tested. Therefore, it is concluded that SSRIs are capable of inhibit the growth in vitro of Candida spp., both in planktonic form, as biofilm, inducing cellular death by apoptosis.}, } @article {pmid28408903, year = {2017}, author = {Lv, Z and Zhao, D and Chang, J and Liu, H and Wang, X and Zheng, J and Huang, R and Lin, Z and Shang, Y and Ye, L and Wu, Y and Han, S and Qu, D}, title = {Anti-bacterial and Anti-biofilm Evaluation of Thiazolopyrimidinone Derivatives Targeting the Histidine Kinase YycG Protein of Staphylococcus epidermidis.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {549}, pmid = {28408903}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis is one of the most important opportunistic pathogens in nosocomial infections. The main pathogenicity associated with S. epidermidis involves the formation of biofilms on implanted medical devices, biofilms dramatically decrease the efficacy of conventional antibiotics and the host immune system. This emphasizes the urgent need for designing novel anti-staphylococcal biofilm agents. Based on the findings that compound 5, targeting the histidine kinase domain of S. epidermidis YycG, possessed bactericidal activity against staphylococci, 39 derivatives of compound 5 with intact thiazolopyrimidinone core structures were newly designed, 7 derivatives were further screened to explore their anti-bacterial and anti-biofilm activities. The seven derivatives strongly inhibited the growth of S. epidermidis and Staphylococcus aureus in the minimal inhibitory concentration range of 1.56-6.25 μM. All the derivatives reduced the proportion of viable cells in mature biofilms. They all displayed low cytotoxicity on mammalian cells and were not hemolytic to human erythrocytes. The biofilm inhibition activities of four derivatives (H5-32, H5-33, H5-34, and H5-35) were further investigated under shearing forces, they all led to significant decreases in the biofilm formation of S. epidermidis. These results were suggestive that the seven derivatives of compound 5 have the potential to be developed into agents for eradicating biofilm-associated infections.}, } @article {pmid28407762, year = {2017}, author = {Belbase, A and Pant, ND and Nepal, K and Neupane, B and Baidhya, R and Baidya, R and Lekhak, B}, title = {Erratum to: Antibiotic resistance and biofilm production among the strains of Staphylococcus aureus isolated in a tertiary care hospital in Nepal.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {16}, number = {1}, pages = {30}, pmid = {28407762}, issn = {1476-0711}, } @article {pmid28407432, year = {2017}, author = {Høiby, N and Bjarnsholt, T and Moser, C and Jensen, PØ and Kolpen, M and Qvist, T and Aanaes, K and Pressler, T and Skov, M and Ciofu, O}, title = {Diagnosis of biofilm infections in cystic fibrosis patients.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {339-343}, doi = {10.1111/apm.12689}, pmid = {28407432}, issn = {1600-0463}, mesh = {*Biofilms ; Cystic Fibrosis/*diagnosis/microbiology ; Humans ; Pseudomonas Infections/*diagnosis/microbiology ; Pseudomonas aeruginosa/genetics/isolation & purification/*physiology ; Sputum/microbiology ; }, abstract = {Chronic Pseudomonas aeruginosa biofilm lung infection in cystic fibrosis patients is the best described biofilm infection in medicine. The initial focus can be the paranasal sinuses and then follows repeated colonization and infection of the lungs by aspiration. The matrix of the biofilms is dominated by alginate and the pathogenesis of tissue damage is immune complex-mediated chronic inflammation dominated by polymorphonuclear leukocytes and their products (DNA, oxygen radicals and proteases). The P. aeruginosa biofilm infection can be diagnosed by microscopy of lung tissue, sputum and mucus from the paranasal sinuses, where aggregates of the bacteria are found surrounded by the abundant alginate matrix. Specific PNA-FISH probes can be used to identify P. aeruginosa and other pathogens in situ in the biofilms. Growth of mucoid colonies from the locations mentioned above is also diagnostic for biofilm infection. Rise of specific anti-P. aeruginosa antibodies is likewise diagnostic, IgG in serum in case of lung infection, sIgA in saliva or nasal secretions in case of paranasal sinus infection. Similar approaches have been developed to diagnose chronic biofilm infections in cystic fibrosis caused by other pathogens e.g., Stenotrophomonas, Burkholderia multivorans, Achromobacter xylosoxidans and Mycobacterium abscessus complex.}, } @article {pmid28407430, year = {2017}, author = {Tofte, N and Nielsen, AC and Trøstrup, H and Andersen, CB and Von Linstow, M and Hansen, B and Biering-Sørensen, F and Høiby, N and Moser, C}, title = {Chronic urinary tract infections in patients with spinal cord lesions - biofilm infection with need for long-term antibiotic treatment.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {385-391}, doi = {10.1111/apm.12685}, pmid = {28407430}, issn = {1600-0463}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacteria/classification/genetics/isolation & purification ; *Bacterial Physiological Phenomena ; *Biofilms/drug effects ; Drug Resistance, Multiple, Bacterial ; Humans ; Spinal Cord Diseases/*complications ; Urinary Tract Infections/*drug therapy/etiology/*microbiology ; }, abstract = {Patients suffering from spinal cord injuries resulting in complete or incomplete paraplegia or tetraplegia are highly disposed to frequent, recurrent or even chronic urinary tract infections (UTIs). The reason for the increased risk of acquiring UTIs is multifactorial, including reduced sensation of classical UTI symptoms, incomplete bladder emptying, frequent catheterizations or chronic urinary tract catheters. Biofilms in relation to UTIs have been shown both on catheters, on concrements or as intracellular bacterial communities (IBCs). Due to the increased risk of acquiring recurrent or chronic UTIs and frequent antibiotic treatments, patients experience an increased risk of being infected with antibiotic-resistant bacteria like extended-spectrum β-lactamase-producing Escherichia coli or Klebsiella spp., but also bacteria like Pseudomonas aeruginosa inherently resistant to several antibiotics. Diagnosing the UTI can also be challenging, especially distinguishing harmless colonization from pathogenic infection. Based on a previous study showing activation of humoral immune response toward UTI pathogens in patients with spinal cord lesions (SCL), the present mini review is an evaluation of using antibody response as an indicator of chronic biofilm UTI. In addition, we evaluated the effect of long-term treatment with antibiotics in patients with SCLs and chronic UTI, defined by culturing of a uropathogen in the urine and elevated specific precipitating antibodies against the same uropathogen in a blood sample. Elimination of chronic UTI, decrease in specific precipitating antibody values and avoiding selection of new multidrug-resistant (MDR) uropathogens were the primary markers for effect of treatment. The results of this evaluation suggest that the long-term treatment strategy in SCL patients with chronic UTI may be effective; however, randomized prospective results are needed to confirm this.}, } @article {pmid28407426, year = {2017}, author = {Høiby, N}, title = {A short history of microbial biofilms and biofilm infections.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {272-275}, doi = {10.1111/apm.12686}, pmid = {28407426}, issn = {1600-0463}, mesh = {Animals ; *Biofilms ; Cystic Fibrosis/microbiology ; History, 17th Century ; History, 18th Century ; History, 19th Century ; History, 20th Century ; History, 21st Century ; Humans ; Microbiology/*history ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/*physiology ; }, abstract = {The observation of aggregated microbes surrounded by a self-produced matrix adhering to surfaces or located in tissues or secretions is old since both Leeuwenhoek and Pasteur have described the phenomenon. In environmental and technical microbiology, biofilms, 80-90 years ago, were already shown to be important for biofouling on submerged surfaces, for example, ships. The concept of biofilm infections and their importance in medicine was, however, initiated in the early 1970s by the observation of heaps of Pseudomonas aeruginosa cells in sputum and lung tissue from chronically infected cystic fibrosis patients. The term biofilm was introduced into medicine in 1985 by J. W. Costerton. During the following decades, the number of published biofilm articles and methods for studying biofilms increased rapidly and it was shown that adhering and nonadhering biofilm infections are widespread in medicine. The medical importance of biofilm infections is now generally accepted and guidelines for prophylaxis, diagnosis, and treatment have been published.}, } @article {pmid28407423, year = {2017}, author = {Zimmerli, W and Sendi, P}, title = {Orthopaedic biofilm infections.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {353-364}, doi = {10.1111/apm.12687}, pmid = {28407423}, issn = {1600-0463}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacteria/drug effects/isolation & purification ; *Bacterial Physiological Phenomena/drug effects ; *Biofilms/drug effects ; Humans ; Orthopedics ; Osteomyelitis/drug therapy/*microbiology ; Prosthesis-Related Infections/drug therapy/*microbiology ; }, abstract = {Many infections of the musculoskeletal system are biofilm infections that develop on non-living surfaces. Microorganisms adhere either on dead bone (sequesters) or implants. As a rule for a curative concept, chronic osteomyelitis or implant-associated bone infection must be treated with a combination of surgery and antimicrobial therapy. If an implant is kept in place, or a new device is implanted before complete healing of infection, a biofilm-active antibiotic should be used. Rifamycins are active against biofilms of staphylococci, and fluoroquinolones against those of Gram-negative bacilli. In this review, the management of chronic osteomyelitis, periprosthetic joint infection and implant-associated osteomyelitis of long bones is presented.}, } @article {pmid28407422, year = {2017}, author = {Xu, Y and Larsen, LH and Lorenzen, J and Hall-Stoodley, L and Kikhney, J and Moter, A and Thomsen, TR}, title = {Microbiological diagnosis of device-related biofilm infections.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {289-303}, doi = {10.1111/apm.12676}, pmid = {28407422}, issn = {1600-0463}, mesh = {Animals ; Bacteria/genetics/growth & development ; Bacterial Infections/*diagnosis/*microbiology/therapy ; *Bacterial Physiological Phenomena ; *Biofilms ; Humans ; Prosthesis-Related Infections/*diagnosis/*microbiology/therapy ; }, abstract = {Medical device-related infections cause undue patient distress, increased morbidity and mortality and pose a huge financial burden on healthcare services. The pathogens are frequently distributed heterogeneously in biofilms, which can persist without being effectively cleared by host immune defenses and antibiotic therapy. At present, there is no 'gold standard' available to reveal the presence of device-related biofilm infections. However, adequate sample collection and logistics, standardised diagnostic methods, and interpretation of results by experienced personnel are important steps in efficient diagnosis and treatment of these infections. The focus of this mini review is on prosthethic joint and cardiovascular implantable device infections, which exemplify permanent devices that are placed in a sterile body site. These device-related infections represent some of the most challenging in terms of both diagnosis and treatment.}, } @article {pmid28407420, year = {2017}, author = {Larsen, T and Fiehn, NE}, title = {Dental biofilm infections - an update.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {376-384}, doi = {10.1111/apm.12688}, pmid = {28407420}, issn = {1600-0463}, mesh = {Animals ; *Biofilms ; Gram-Negative Bacteria/genetics/*physiology ; Gram-Negative Bacterial Infections/*microbiology ; Humans ; Stomatognathic Diseases/*microbiology ; Tooth/microbiology ; }, abstract = {Teeth are colonized by oral bacteria from saliva containing more than 700 different bacterial species. If removed regularly, the dental biofilm mainly comprises oral streptococci and is regarded as resident microflora. But if left undisturbed, a complex biofilm containing up to 100 bacterial species at a site will build up and may eventually cause development of disease. Depending on local ecological factors, the composition of the dental biofilm may vary considerably. With access to excess carbohydrates, the dental biofilm will be dominated by mainly gram-positive carbohydrate-fermenting bacteria causing demineralization of teeth, dental caries, which may further lead to inflammation and necrosis in the pulp and periapical region, i.e., pulpitis and periapical periodontitis. In supra- and subgingival biofilms, predominantly gram-negative, anaerobic proteolytic bacteria will colonize and cause gingival inflammation and breakdown of supporting periodontal fibers and bone and ultimately tooth loss, i.e., gingivitis, chronic or aggressive periodontitis, and around dental implants, peri-implantitis. Furthermore, bacteria from the dental biofilm may spread to other parts of the body by bacteremia and cause systemic disease. Basically, prevention and treatment of dental biofilm infections are achieved by regular personal and professional removal of the dental biofilm.}, } @article {pmid28407419, year = {2017}, author = {Ciofu, O and Rojo-Molinero, E and Macià, MD and Oliver, A}, title = {Antibiotic treatment of biofilm infections.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {125}, number = {4}, pages = {304-319}, doi = {10.1111/apm.12673}, pmid = {28407419}, issn = {1600-0463}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy/microbiology ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Humans ; }, abstract = {Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due to multiple tolerance mechanisms (phenotypic resistance). This causes persistence of biofilm infections in spite of antibiotic exposure which predisposes to antibiotic resistance development (genetic resistance). Understanding the interplay between phenotypic and genetic resistance mechanisms acting on biofilms, as well as appreciating the diversity of environmental conditions of biofilm infections which influence the effect of antibiotics are required in order to optimize the antibiotic treatment of biofilm infections. Here, we review the current knowledge on phenotypic and genetic resistance in biofilms and describe the potential strategies for the antibiotic treatment of biofilm infections. Of note is the optimization of PK/PD parameters in biofilms, high-dose topical treatments, combined and sequential/alternate therapies or the use antibiotic adjuvants.}, } @article {pmid28406736, year = {2017}, author = {Cai, W and Arias, CR}, title = {Biofilm Formation on Aquaculture Substrates by Selected Bacterial Fish Pathogens.}, journal = {Journal of aquatic animal health}, volume = {29}, number = {2}, pages = {95-104}, doi = {10.1080/08997659.2017.1290711}, pmid = {28406736}, issn = {1548-8667}, mesh = {Aeromonas hydrophila/physiology ; Animals ; *Aquaculture ; Bacterial Adhesion ; Biofilms/*growth & development ; Edwardsiella ictaluri/physiology ; Fish Diseases/*microbiology ; Flavobacterium/physiology ; *Ictaluridae/microbiology ; }, abstract = {The objective of this study was to determine whether common bacterial catfish pathogens could attach and colonize surfaces commonly found in aquaculture facilities. In addition, we evaluated the role of calcium in biofilm formation. Attachment to polystyrene plates was used to quantify biofilm formation by five bacterial pathogens (i.e., Flavobacterium columnare, Aeromonas hydrophila, Edwardsiella ictaluri, E. tarda, and E. piscicida). Flavobacterium columnare and A. hydrophila formed thick biofilms that were enhanced by calcium supplementation. Biofilm formation was significantly lower in all Edwardsiella species tested and calcium had little to no effect on Edwardsiella biofilm formation. Attachment to natural and artificial surfaces was quantified by a standard plate count method. Scanning electron microscopy (SEM) was used to confirm biofilm formation on the substrates. Flavobacterium columnare formed biofilm on the liner, flexible PVC, and nets. Bamboo prevented F. columnare attachment and inhibited cell growth. Aeromonas hydrophila and E. ictaluri formed biofilm on all materials tested, although significant differences were found among substrates. While E. ictaluri failed to form biofilm on microtiter polystyrene plates, it was able to colonize and multiply on all aquaculture materials tested. Our results demonstrated that common bacterial pathogens had the potential of colonizing surfaces and may use biofilm as reservoirs in fish farms. Received July 19, 2016; accepted January 19, 2017.}, } @article {pmid28406615, year = {2017}, author = {Gupta, A and Fuentes, SM and Grove, A}, title = {Redox-Sensitive MarR Homologue BifR from Burkholderia thailandensis Regulates Biofilm Formation.}, journal = {Biochemistry}, volume = {56}, number = {17}, pages = {2315-2327}, pmid = {28406615}, issn = {1520-4995}, support = {R15 GM107825/GM/NIGMS NIH HHS/United States ; }, mesh = {ATP-Binding Cassette Transporters/chemistry/genetics/metabolism ; Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Burkholderia/enzymology/growth & development/*physiology ; Cysteine/chemistry ; Cystine/chemistry ; DNA, Intergenic ; Dimerization ; Enzyme Stability ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Hot Temperature ; Metalloproteases/chemistry/genetics/*metabolism ; *Models, Biological ; Mutation ; Operon ; Oxidation-Reduction ; Peptide Fragments/chemistry/genetics/metabolism ; Protein Interaction Domains and Motifs ; Recombinant Fusion Proteins/chemistry/metabolism ; Recombinant Proteins/chemistry/metabolism ; Virulence Factors/chemistry/genetics/*metabolism ; }, abstract = {Biofilm formation by pathogenic Burkholderia species is a serious complication as it renders the bacteria resistant to antibiotics and host defenses. Using B. thailandensis, we report here a novel redox-sensitive member of the multiple antibiotic resistance regulator (MarR) protein family, BifR, which represses biofilm formation. BifR is encoded as part of the emrB-bifR operon; emrB-bifR is divergent to ecsC, which encodes a putative LasA protease. In Pseudomonas aeruginosa, LasA has been implicated in virulence by contributing to cleavage of elastase. BifR repressed the expression of ecsC and emrB-bifR, and expression was further repressed under oxidizing conditions. BifR bound two sites in the intergenic region between ecsC and emrB-bifR with nanomolar affinity under both reducing and oxidizing conditions; however, oxidized BifR formed a disulfide-linked dimer-of-dimers, a covalent linkage that was absent in BifR-C104A in which the redox-active cysteine was replaced with alanine. BifR also repressed an operon encoding enzymes required for synthesis of phenazine antibiotics, which function as alternate respiratory electron receptors, and inactivation of bifR resulted in enhanced biofilm formation. Taken together, our data suggest that BifR functions to control LasA production and expression of genes involved in biofilm formation, in part by regulating synthesis of alternate electron acceptors that promote survival in the oxygen-limiting environment of a biofilm. The correlation between increased repression of emrB-bifR under oxidative conditions and the formation of a covalently linked BifR dimer-of-dimers suggests that BifR may modulate gene activity in response to cellular redox state.}, } @article {pmid28406080, year = {2017}, author = {Uhlich, GA and Chen, CY and Cottrell, BJ and Andreozzi, E and Irwin, PL and Nguyen, LH}, title = {Genome amplification and promoter mutation expand the range of csgD-dependent biofilm responses in an STEC population.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {4}, pages = {611-621}, doi = {10.1099/mic.0.000448}, pmid = {28406080}, issn = {1465-2080}, mesh = {Bacterial Proteins/biosynthesis/*genetics ; Biofilms/*growth & development ; Cellulose/biosynthesis/genetics ; DNA-Directed RNA Polymerases/*genetics ; Escherichia coli O157/*genetics ; Escherichia coli Proteins/*genetics ; Fimbriae Proteins/biosynthesis/genetics ; *Gene Expression Regulation, Bacterial ; Genome, Bacterial/genetics ; Promoter Regions, Genetic/genetics ; Sigma Factor/*genetics ; Trans-Activators/*genetics ; }, abstract = {Expression of the major biofilm components of E. coli, curli fimbriae and cellulose, requires the CsgD transcription factor. A complex regulatory network allows environmental control of csgD transcription and biofilm formation. However, most clinical serotype O157 : H7 strains contain prophage insertions in the csgD regulator, mlrA, or mutations in other regulators that restrict csgD expression. These barriers can be circumvented by certain compensating mutations that restore higher csgD expression. One mechanism is via csgD promoter mutations that switch sigma factor utilization. Biofilm-forming variants utilizing RpoD rather than RpoS have been identified in glycerol freezer stocks of the non-biofilm-forming food-borne outbreak strain, ATCC 43894. In this study we used whole genome sequencing and RNA-seq to study genotypic and transcriptomic differences between those strains. In addition to defining the consequences of the csgD promoter switch and identifying new csgD-controlled genes, we discovered a region of genome amplification in our laboratory stock of 43894 (designated 43894OW) that contributed to the regulation of csgD-dependent properties.}, } @article {pmid28405479, year = {2017}, author = {Kıvanç, SA and Kıvanç, M and Kılıç, V and Güllülü, G and Özmen, AT}, title = {Comparison of Biofilm Formation Capacities of Two Clinical Isolates of Staphylococcus Epidermidis with and without icaA and icaD Genes on Intraocular Lenses.}, journal = {Turkish journal of ophthalmology}, volume = {47}, number = {2}, pages = {68-73}, pmid = {28405479}, issn = {2149-8695}, abstract = {OBJECTIVES: To compare biofilm formations of two Staphylococcus epidermidis (S. epidermidis) isolates with known biofilm formation capacities on four different intraocular lenses (IOL) that have not been studied before.

MATERIALS AND METHODS: Two isolates obtained from ocular surfaces and identified in previous studies and stored at -86 °C in 15% glycerol in the microbiology laboratory of the Anadolu University Department of Biology were purified and used in the study. The isolates were S. epidermidis KA 15.8 (ICA+), a known biofilm producer isolate positive for icaA, icaD and bap genes, and S. epidermidis KA 14.5 (ICA-), known as a non-biofilm producer isolate negative for icaA, icaD and bap genes. The biofilm formation capacities of the 2 isolates on 4 different IOLs were compared. Two of the IOLs were acrylic (UD613 [IOL A], Turkey; SA60AT [IOL B], USA), and the other two were polymethyl methacrylate (PMMA) (B60130C [IOL C], India; B55125C [IOL D], India). Bacterial enumeration and optical density measurements were done from biofilms that formed on the IOLs. Biofilms were imaged using scanning electron microscopy.

RESULTS: Mean bacterial counts on the IOLs were 7.1±0.4 log10 CFU/mL with the ICA+ isolate, and 6.7±0.8 log10 CFU/mL with the ICA- isolate; there were no statistically significant differences. Biofilm formation was lower with acrylic lenses than PMMA lenses with both isolates (p=0.009 and p=0.013). The highest biofilm production was obtained on IOL C (PMMA) (p<0.001) and the lowest was obtained on IOL A (hydrophilic acrylic) (p<0.001).

CONCLUSION: Bacterial counts after biofilm formation were lower on acrylic lenses, especially hydrophilic acrylic with hydrophobic properties. Further animal and in vivo studies are required to support the findings of this study.}, } @article {pmid28405263, year = {2017}, author = {Granick, MS and Paribathan, C and Shanmugam, M and Ramasubbu, N}, title = {Direct-Contact Low-Frequency Ultrasound Clearance of Biofilm From Metallic Implant Materials.}, journal = {Eplasty}, volume = {17}, number = {}, pages = {e13}, pmid = {28405263}, issn = {1937-5719}, abstract = {Introduction: Biofilms are recognized as a significant deterrent to wound healing and to the management of exposed or infected surgical implants. Biofilms can be disrupted by a variety of enzymatic and mechanical interventions. This experiment was designed to determine whether direct-contact low-frequency ultrasound has the ability to clear biofilms and what then happens to the released bacteria. Methods:Staphylococcus epidermidis biofilm was grown on the surfaces of metallic discs composed of titanium and stainless steel, comparable with the alloys used in surgical implants. The discs were treated with a control of irrigation and no ultrasound, followed by the ultrasound for a 10 second of exposure at a mid-level power setting. The irrigation materials used was either normal saline or hypochlorous acid. The effluent was cultured to determine colony-forming units, and the discs were stained with crystal violet to determine whether there was a residual biofilm. Results: The biofilm was cleared completely from all discs when treated with direct-contact low-frequency ultrasound. However, the released bacteria were viable and could be cultured from the effluent when saline was used as the irrigation medium. When hypochlorous acid was used as the irrigation medium, there was complete killing of all planktonic bacteria. Conclusion: Direct-contact low-frequency ultrasound is effective when used to clear biofilms from metallic implant materials. By using hypochlorous acid as the irrigant during treatment, all of the bacteria released from the biofilm were killed as well. The implications for clinical application are important and need to be independently studied.}, } @article {pmid28403796, year = {2017}, author = {Reyes-Darias, JA and Krell, T}, title = {Riboswitches as Potential Targets for the Development of Anti-Biofilm Drugs.}, journal = {Current topics in medicinal chemistry}, volume = {}, number = {}, pages = {}, doi = {10.2174/1568026617666170407163517}, pmid = {28403796}, issn = {1873-4294}, abstract = {In nature, bacteria can exist as single motile cells or as sessile cellular community, known as microbial biofilms. Bacteria within biofilms are embedded in a self-produced extracellular matrix that makes them more resistant to antibiotic treatment and responses of the host immune system. Microbial biofilms are very important in medicine since they are associated with several human diseases such as dental caries, periodontitis, otitis media, infective endocarditis, infectious kidney stones, osteomyelitis or prostatitis. In addition, biofilms formed on the surface of clinical devices such as pacemakers, implants and catheters are difficult to treat, which underlines the clinical relevance of biofilm formation. At the molecular level, the switch from the planktonic state to biofilm formation is regulated primarily by bis- (3'-5)-cyclic dimeric guanosine monophosphate (c-di-GMP). C-di-GMP performs its function by binding to a wide variety of proteins, but also to riboswitches. C-di-GMP riboswitches are RNA regulatory elements located in the 5'-untranslated regions (5'-UTRs) of RNA messengers (mRNA) from genes involved in virulence, motility and biofilm formation, which are regulated by changes in the intracellular concentration of c-di-GMP. This review discusses the role of c-di-GMP responsive riboswitches as potential targets for the design of anti-biofilm agents.}, } @article {pmid28403648, year = {2017}, author = {Parkar, SG and Eady, S and Cabecinha, M and Skinner, MA}, title = {Consumption of apple-boysenberry beverage decreases salivary Actinomyces naeslundii and their adhesion in a multi-species biofilm model.}, journal = {Beneficial microbes}, volume = {8}, number = {2}, pages = {299-307}, doi = {10.3920/BM2016.0061}, pmid = {28403648}, issn = {1876-2891}, mesh = {Actinomyces/*growth & development ; Adult ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Bacterial Load/*drug effects ; Biofilms/*drug effects/growth & development ; Female ; *Fruit and Vegetable Juices ; Humans ; Lactobacillus/*growth & development ; Male ; Malus ; Middle Aged ; Rubus ; Saliva/*microbiology ; Streptococcus mutans/*growth & development ; }, abstract = {We hypothesised that consumption of beverage rich in both fibre and polyphenols, rather than each bioactive alone, will modulate populations of selected salivary bacteria, and their adhesion characteristics and that some of these effects may be due to the anti-microbial activity of the beverage bioactives. We investigated the effect of 4 weeks' consumption of beverages, rich in apple fibre, boysenberry polyphenols, or both on salivary bacteria in healthy subjects. In this placebo-controlled crossover study, saliva samples were collected at the beginning and end of each treatment period, and used for qPCR quantitation of Lactobacillus spp., Actinomyces naeslundii and Streptococcus mutans. The counts of salivary A. naeslundii decreased after the consumption of the apple-boysenberry beverage (P<0.05, Student's t-test). We also examined the effect of the subjects' saliva on bacterial adhesion using a mixed species biofilm model. The salivary pellicles prepared before and after each treatment were inoculated with laboratory strains of A. naeslundii, Lactobacillus rhamnosus and S. mutans and tested for biofilm formation. The post appleboysenberry beverage salivary pellicle significantly decreased the adhesion of A. naeslundii at the end of both 3 and 24 h, in the in vitro biofilm. A 1/16 dilution of the apple-boysenberry beverage itself decreased the proliferation of test strains of A. naeslundii and S. mutans by 51 and 55%, respectively (P<0.005), indicating the antimicrobial activity of its bioactives. This study demonstrated that consumption of apple-boysenberry beverage, rather than apple or the boysenberry beverage alone or the placebo, decreased salivary A. naeslundii and their adhesion under laboratory conditions. These changes are factors that influence oral microecology and potentially oral health.}, } @article {pmid28403635, year = {2017}, author = {Oliveros-Muñoz, JM and Calderón-Alvarado, MP and Martínez-González, GM and Navarrete-Bolaños, JL and Jiménez-Islas, H}, title = {One-domain approach for studying multiphase transport phenomena in biofilm growing systems.}, journal = {Biofouling}, volume = {33}, number = {4}, pages = {336-351}, doi = {10.1080/08927014.2017.1311326}, pmid = {28403635}, issn = {1029-2454}, mesh = {Algorithms ; Biofilms/*growth & development ; Bioreactors/microbiology ; Biotechnology/methods ; Diffusion ; *Models, Theoretical ; Porosity ; Surface Properties ; }, abstract = {The one-domain approach (ODA) was used as an alternative to solve fluid-biofilm interfacial behavior in a 2-D model for diffusion-reaction-convection coupled with prediction of irregular growth of biofilms via a cellular automaton strategy. The simulations exhibited errors of <7% compared with the porosity of a previously reported capillary experimental system. Additionally, biofilm surface geometrical aspects were satisfactorily compared with reports of experimental and similar rigorously simulated benchmark systems. The method developed was applied to simulate typical biofilm systems predicting recirculation flow patterns, interface concentration profiles, and clogging of the inlet section of the capillary tube, which are phenomena that affect the efficiency of diverse biotechnological applications, including membrane bioreactors and biofilters. The ODA method applied to the governing equations of momentum and mass transfer combined with a cellular automaton algorithm is a suitable and straightforward approach for modeling solid-state fermentation at different sophistication levels.}, } @article {pmid28403360, year = {2017}, author = {Andrucioli, MC and Faria, G and Nelson-Filho, P and Romano, FL and Matsumoto, MA}, title = {Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets.}, journal = {Journal of applied oral science : revista FOB}, volume = {25}, number = {2}, pages = {196-202}, pmid = {28403360}, issn = {1678-7765}, mesh = {Acrylic Resins/*pharmacology ; Adolescent ; Aluminum Silicates/*pharmacology ; Analysis of Variance ; Bacterial Load ; Biofilms/*drug effects ; Cariostatic Agents/pharmacology ; Child ; Dental Bonding/methods ; Fluorides, Topical/*pharmacology ; Glass Ionomer Cements/*pharmacology ; Humans ; Orthodontic Brackets/*microbiology ; Reproducibility of Results ; Resin Cements/pharmacology ; Saliva/*microbiology ; Streptococcus mutans/*drug effects/isolation & purification/physiology ; Time Factors ; Young Adult ; }, abstract = {Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.}, } @article {pmid28403171, year = {2017}, author = {Thomen, P and Robert, J and Monmeyran, A and Bitbol, AF and Douarche, C and Henry, N}, title = {Bacterial biofilm under flow: First a physical struggle to stay, then a matter of breathing.}, journal = {PloS one}, volume = {12}, number = {4}, pages = {e0175197}, pmid = {28403171}, issn = {1932-6203}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Escherichia coli/*physiology ; *Hydrodynamics ; Microfluidic Analytical Techniques ; Oxygen/*metabolism ; *Stress, Mechanical ; }, abstract = {Bacterial communities attached to surfaces under fluid flow represent a widespread lifestyle of the microbial world. Through shear stress generation and molecular transport regulation, hydrodynamics conveys effects that are very different by nature but strongly coupled. To decipher the influence of these levers on bacterial biofilms immersed in moving fluids, we quantitatively and simultaneously investigated physicochemical and biological properties of the biofilm. We designed a millifluidic setup allowing to control hydrodynamic conditions and to monitor biofilm development in real time using microscope imaging. We also conducted a transcriptomic analysis to detect a potential physiological response to hydrodynamics. We discovered that a threshold value of shear stress determined biofilm settlement, with sub-piconewton forces sufficient to prevent biofilm initiation. As a consequence, distinct hydrodynamic conditions, which set spatial distribution of shear stress, promoted distinct colonization patterns with consequences on the growth mode. However, no direct impact of mechanical forces on biofilm growth rate was observed. Consistently, no mechanosensing gene emerged from our differential transcriptomic analysis comparing distinct hydrodynamic conditions. Instead, we found that hydrodynamic molecular transport crucially impacts biofilm growth by controlling oxygen availability. Our results shed light on biofilm response to hydrodynamics and open new avenues to achieve informed design of fluidic setups for investigating, engineering or fighting adherent communities.}, } @article {pmid28402558, year = {2017}, author = {Malone, M and Johani, K and Jensen, SO and Gosbell, IB and Dickson, HG and McLennan, S and Hu, H and Vickery, K}, title = {Effect of cadexomer iodine on the microbial load and diversity of chronic non-healing diabetic foot ulcers complicated by biofilm in vivo.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {7}, pages = {2093-2101}, pmid = {28402558}, issn = {1460-2091}, mesh = {Aged ; Aged, 80 and over ; Anti-Bacterial Agents/administration & dosage/therapeutic use ; Anti-Infective Agents, Local/administration & dosage/*therapeutic use ; Bacteria/drug effects/genetics ; Bacterial Load/*drug effects/genetics ; Biofilms/*drug effects ; Cohort Studies ; Diabetic Foot/*complications/microbiology ; Female ; Genetic Variation/drug effects ; High-Throughput Nucleotide Sequencing ; Humans ; In Situ Hybridization, Fluorescence ; Iodophors/administration & dosage/*therapeutic use ; Male ; Middle Aged ; Pilot Projects ; Wound Healing/drug effects ; }, abstract = {OBJECTIVES: The performance of cadexomer iodine was determined against microbial populations from chronic non-healing diabetic foot ulcers (DFUs) complicated by biofilm in vivo , using molecular, microscopy and zymography methods.

METHODS: Chronic non-healing DFUs due to suspected biofilm involvement were eligible for enrolment. DNA sequencing and real-time quantitative PCR was used to determine the microbial load and diversity of tissue punch biopsies obtained pre- and post-treatment. Scanning electron microscopy and/or fluorescence in situ hybridization confirmed the presence or absence of biofilm. Zymography was used to determine levels of wound proteases.

RESULTS: Seventeen participants were recruited over a 6 month period. Scanning electron microscopy and or fluorescence in situ hybridization confirmed the presence of biofilm in all samples. Eleven participants exhibited log 10 reductions in microbial load after treatment (range 1-2 log 10) in comparison with six patients who experienced <1 log 10 reduction (P  =   0.04). Samples were tested for levels of wound proteases pre- and post-treatment. Reductions in the microbial load correlated to reductions in wound proteases pre- and post-treatment (P  =   0.03).

CONCLUSIONS: To the best of our knowledge, this study represents the first in vivo evidence, employing a range of molecular and microscopy techniques, of the ability of cadexomer iodine to reduce the microbial load of chronic non-healing DFUs complicated by biofilm. Further analyses correlating log reductions to optimal duration of therapy and improvements in clinical parameters of wound healing in a larger cohort are required.}, } @article {pmid28402313, year = {2017}, author = {Zheng, Z and Li, Y and Li, J and Zhang, Y and Bian, W and Wei, J and Zhao, B and Yang, J}, title = {Effects of carbon sources, COD/NO2[-]-N ratios and temperature on the nitrogen removal performance of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {75}, number = {7-8}, pages = {1712-1721}, doi = {10.2166/wst.2017.035}, pmid = {28402313}, issn = {0273-1223}, mesh = {Ammonium Compounds/analysis/*metabolism ; Bacteria/*metabolism ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/microbiology ; Carbon/analysis/*metabolism ; Denitrification ; Nitrification ; Nitrites/analysis/*metabolism ; Nitrogen/analysis/*metabolism ; Oxidation-Reduction ; Sewage/microbiology ; Temperature ; Wastewater/chemistry/microbiology ; }, abstract = {The aim of the present work was to evaluate the effects of carbon sources and chemical oxygen demand (COD)/NO2[-]-N ratios on the anammox-denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm. Also, the anammox activities of the SNAD biofilm were investigated under different temperature. Kaldnes rings taken from the SNAD biofilm reactor were operated in batch tests to determine the nitrogen removal rates. As a result, with the carbon source of sodium acetate, the appropriate COD/NO2[-]-N ratios for the anammox-denitrification coupling process were 1 and 2. With the COD/NO2[-]-N ratios of 1, 2, 3, 4 and 5, the corresponding NO2[-]-N consumption via anammox was 87.1%, 52.2%, 29.3%, 23.7% and 16.3%, respectively. However, with the carbon source of sodium propionate and glucose, the anammox bacteria was found to perform higher nitrite competitive ability than denitrifiers at the COD/NO2[-]-N ratio of 5. Also, the SNAD biofilm could perform anammox activity at 15 °C with the nitrogen removal rate of 0.071 kg total inorganic nitrogen per kg volatile suspended solids per day. These results indicated that the SNAD biofilm process might be feasible for the treatment of municipal wastewater at normal temperature.}, } @article {pmid28402186, year = {2017}, author = {Hou, HM and Jiang, F and Zhang, GL and Wang, JY and Zhu, YH and Liu, XY}, title = {Inhibition of Hafnia alvei H4 Biofilm Formation by the Food Additive Dihydrocoumarin.}, journal = {Journal of food protection}, volume = {80}, number = {5}, pages = {842-847}, doi = {10.4315/0362-028X.JFP-16-460}, pmid = {28402186}, issn = {1944-9097}, abstract = {Quorum sensing (QS) is an intercellular signaling and gene regulatory mechanism that is implicated in food spoilage caused by bacteria. Thus, blocking QS may suppress QS-controlled phenotypes of these bacteria that are responsible for food spoilage. Biofilm formation is closely related to bacterial infection, and it is also a major mechanism responsible for the increased resistance of biofilm-associated bacteria to antimicrobial drugs. Food spoilage and biofilm formation caused by food-related bacteria have posed a significant problem for the food industry. Thus, adopting an antibiofilm approach would provide an alternative to an antibiotic strategy. Dihydrocoumarin is a compound that is derived from coumarin, a known natural QS inhibitor that has been used as an additive in food. Hafnia alvei is a spoilage bacterium; H. alvei H4 was isolated from ready-to-eat sea cucumber. Considering that QS and biofilm are often closely linked, this research aimed to detect the effect of dihydrocoumarin on the production of violacein by Chromobacterium violaceum 026 and to evaluate the inhibitory effect of dihydrocoumarin on the formation of biofilm by H. alvei H4 by using violacein and crystal violet assays. C. violaceum 026 treated with dihydrocoumarin showed as much as 70.1% reduction in QS-mediated production of violacein compared with untreated cells, while exhibiting no significant change in growth. H. alvei H4 treated with dihydrocoumarin displayed 75.8% reduction in swimming motility, and as much as 89.4% reduction in biofilm formation compared with the nontreated cells, with the reduction in both cases being dependent on the concentration of dihydrocoumarin. Scanning electron microscopy showed that dihydrocoumarin could effectively destroy the biofilm structure of H. alvei H4 and decrease biofilm density. These findings indicate that dihydrocoumarin can be developed into a new QS inhibitor or antibiofilm agent for controlling food spoilage and potentially investigated to increase food safety.}, } @article {pmid28401747, year = {2017}, author = {Makovcova, J and Babak, V and Kulich, P and Masek, J and Slany, M and Cincarova, L}, title = {Dynamics of mono- and dual-species biofilm formation and interactions between Staphylococcus aureus and Gram-negative bacteria.}, journal = {Microbial biotechnology}, volume = {10}, number = {4}, pages = {819-832}, pmid = {28401747}, issn = {1751-7915}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Enterobacteriaceae/growth & development/*physiology ; Gentian Violet/analysis ; *Microbial Interactions ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Staining and Labeling ; Staphylococcus aureus/growth & development/*physiology ; }, abstract = {Microorganisms are not commonly found in the planktonic state but predominantly form dual- and multispecies biofilms in almost all natural environments. Bacteria in multispecies biofilms cooperate, compete or have neutral interactions according to the involved species. Here, the development of mono- and dual-species biofilms formed by Staphylococcus aureus and other foodborne pathogens such as Salmonella enterica subsp. enterica serovar Enteritidis, potentially pathogenic Raoultella planticola and non-pathogenic Escherichia coli over the course of 24, 48 and 72 h was studied. Biofilm formation was evaluated by the crystal violet assay (CV), enumeration of colony-forming units (CFU cm[-2]) and visualization using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In general, Gram-negative bacterial species and S. aureus interacted in a competitive manner. The tested Gram-negative bacteria grew better in mixed dual-species biofilms than in their mono-species biofilms as determined using the CV assay, CFU ml[-2] enumeration, and CLSM and SEM visualization. In contrast, the growth of S. aureus biofilms was reduced when cultured in dual-species biofilms. CLSM images revealed grape-like clusters of S. aureus and monolayers of Gram-negative bacteria in both mono- and dual-species biofilms. S. aureus clusters in dual-species biofilms were significantly smaller than clusters in S. aureus mono-species biofilms.}, } @article {pmid28401067, year = {2017}, author = {Liu, J and Sun, L and Liu, W and Guo, L and Liu, Z and Wei, X and Ling, J}, title = {A Nuclease from Streptococcus mutans Facilitates Biofilm Dispersal and Escape from Killing by Neutrophil Extracellular Traps.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {97}, pmid = {28401067}, issn = {2235-2988}, mesh = {Biofilms/*growth & development ; Deoxyribonucleases/genetics/*pharmacology ; Extracellular Traps/*drug effects/*metabolism ; Gene Expression Regulation, Bacterial ; Humans ; Microbial Viability ; Neutrophils/immunology/microbiology ; Reactive Oxygen Species/analysis ; Recombinant Proteins ; Sequence Deletion ; Streptococcus mutans/*enzymology/genetics/immunology ; }, abstract = {Streptococcus mutans is the primary etiologic agent of dental caries and occasionally infective endocarditis, with the ability to form biofilms and disperse cells into distal sites to exacerbate and spread infection. In this study, we identified a nuclease (DeoC) as a S. mutans biofilm dispersal modulating factor through microarray analysis. In vitro assays revealed a dispersal defect of a deoC deletion mutant, and functional studies with purified protein were indicative of the biofilm dispersal activity of DeoC. Neutrophils are a key host response factor restraining bacterial spreading through the formation of neutrophil extracellular traps (NETs), which consist of a nuclear DNA backbone associated with antimicrobial peptides. Therefore, we hypothesized that the dispersed S. mutans might utilize DeoC to degrade NETs and escape killing by the immune system. It was found that S. mutans induced NET formation upon contact with neutrophils, while the presence of NETs in turn enhanced the deoC expression of S. mutans. Fluorescence microscopy inspection showed that deoC deletion resulted in a decreased NET degradation ability of S. mutans and enhanced susceptibility to neutrophil killing. Data obtained from this study assigned two important roles for DeoC in S. mutans: contributing to the spread of infection through mediating biofilm dispersal, and facilitating the escape of S. mutans from neutrophil killing through NET degradation.}, } @article {pmid28400754, year = {2017}, author = {Jones, AA and Bennett, PC}, title = {Mineral Ecology: Surface Specific Colonization and Geochemical Drivers of Biofilm Accumulation, Composition, and Phylogeny.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {491}, pmid = {28400754}, issn = {1664-302X}, abstract = {This study tests the hypothesis that surface composition influences microbial community structure and growth of biofilms. We used laboratory biofilm reactors (inoculated with a diverse subsurface community) to explore the phylogenetic and taxonomic variability in microbial communities as a function of surface type (carbonate, silicate, aluminosilicate), media pH, and carbon and phosphate availability. Using high-throughput pyrosequencing, we found that surface type significantly controlled ~70-90% of the variance in phylogenetic diversity regardless of environmental pressures. Consistent patterns also emerged in the taxonomy of specific guilds (sulfur-oxidizers/reducers, Gram-positives, acidophiles) due to variations in media chemistry. Media phosphate availability was a key property associated with variation in phylogeny and taxonomy of whole reactors and was negatively correlated with biofilm accumulation and α-diversity (species richness and evenness). However, mineral-bound phosphate limitations were correlated with less biofilm. Carbon added to the media was correlated with a significant increase in biofilm accumulation and overall α-diversity. Additionally, planktonic communities were phylogenetically distant from those in biofilms. All treatments harbored structurally (taxonomically and phylogenetically) distinct microbial communities. Selective advantages within each treatment encouraged growth and revealed the presence of hundreds of additional operational taxonomix units (OTU), representing distinct consortiums of microorganisms. Ultimately, these results provide evidence that mineral/rock composition significantly influences microbial community structure, diversity, membership, phylogenetic variability, and biofilm growth in subsurface communities.}, } @article {pmid28400170, year = {2017}, author = {Brethauer, S and Robert Lawrence, S and Michael Hans-Peter, S}, title = {Enhanced simultaneous saccharification and fermentation of pretreated beech wood by in situ treatment with the white rot fungus Irpex lacteus in a membrane aerated biofilm reactor.}, journal = {Bioresource technology}, volume = {237}, number = {}, pages = {135-138}, doi = {10.1016/j.biortech.2017.03.050}, pmid = {28400170}, issn = {1873-2976}, mesh = {*Biofilms ; Ethanol ; *Fagus ; *Fermentation ; Fungi ; Hydrolysis ; Lignin ; Wood ; }, abstract = {The aim of the present study was to investigate the combination of steam pretreatment and biological treatment with lignin degrading fungal strains in order to enable efficient bioprocessing of beech wood to ethanol. In a sequential process of steam and fungal pretreatment followed by enzymatic hydrolysis, Irpex lacteus almost doubled the glucose yield for mildly pretreated beech wood, but could not improve yields for more severely pretreated substrates. However, when simultaneous saccharification and fermentation is combined with in situ I. lacteus treatment, which is enabled by the application of a membrane aerated biofilm reactor, ethanol yields of optimally steam pretreated beech could be improved from 65 to 80%. Generally, in situ fungal treatment during bioprocessing of lignocellulose is an interesting method to harness the versatile abilities of white rot fungi.}, } @article {pmid28397768, year = {2017}, author = {Hou, Y and Wang, Z and Zhang, P and Bai, H and Sun, Y and Duan, J and Mu, H}, title = {Lysozyme Associated Liposomal Gentamicin Inhibits Bacterial Biofilm.}, journal = {International journal of molecular sciences}, volume = {18}, number = {4}, pages = {}, pmid = {28397768}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Gentamicins/*pharmacology ; Humans ; Liposomes/*metabolism ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Muramidase/*metabolism ; Pseudomonas aeruginosa/*drug effects/physiology/ultrastructure ; Staphylococcus aureus/*drug effects/physiology/ultrastructure ; }, abstract = {Bacteria on living or inert surfaces usually form biofilms which make them highly resistant to antibiotics and immune clearance. Herein, we develop a simple approach to overcome the above conundrum through lysozyme-associated liposomal gentamicin (LLG). The association of lysozyme to the surface of liposomes can effectively reduce the fusion of liposomes and undesirable payload release in regular storage or physiological environments. The LLG was more effective at damaging established biofilms and inhibiting biofilm formation of pathogens including Gram-positive and Gram-negative bacteria than gentamicin alone. This strategy may provide a novel approach to treat infections due to bacterial biofilm.}, } @article {pmid28396655, year = {2017}, author = {Navarro, JB and Mashburn-Warren, L and Bakaletz, LO and Bailey, MT and Goodman, SD}, title = {Enhanced Probiotic Potential of Lactobacillus reuteri When Delivered as a Biofilm on Dextranomer Microspheres That Contain Beneficial Cargo.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {489}, pmid = {28396655}, issn = {1664-302X}, support = {R01 GM123482/GM/NIGMS NIH HHS/United States ; }, abstract = {As with all orally consumed probiotics, the Gram-positive bacterium Lactobacillus reuteri encounters numerous challenges as it transits through the gastrointestinal tract of the host, including low pH, effectors of the host immune system, as well as competition with commensal and pathogenic bacteria, all of which can greatly reduce the availability of live bacteria for therapeutic purposes. Recently we showed that L. reuteri, when adhered in the form of a biofilm to a semi-permeable biocompatible dextranomer microsphere, reduces the incidence of necrotizing enterocolitis by 50% in a well-defined animal model following delivery of a single prophylactic dose. Herein, using the same semi-permeable microspheres, we showed that providing compounds beneficial to L. reuteri as diffusible cargo within the microsphere lumen resulted in further advantageous effects including glucosyltransferase-dependent bacterial adherence to the microsphere surface, resistance of bound bacteria against acidic conditions, enhanced adherence of L. reuteri to human intestinal epithelial cells in vitro, and facilitated production of the antimicrobial compound reuterin and the anti-inflammatory molecule histamine. These data support continued development of this novel probiotic formulation as an adaptable and effective means for targeted delivery of cargo beneficial to the probiotic bacterium.}, } @article {pmid28396417, year = {2017}, author = {Graham, CE and Cruz, MR and Garsin, DA and Lorenz, MC}, title = {Enterococcus faecalis bacteriocin EntV inhibits hyphal morphogenesis, biofilm formation, and virulence of Candida albicans.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {17}, pages = {4507-4512}, pmid = {28396417}, issn = {1091-6490}, support = {F31 AI122725/AI/NIAID NIH HHS/United States ; R01 AI075091/AI/NIAID NIH HHS/United States ; R01 AI076406/AI/NIAID NIH HHS/United States ; R01 AI110432/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacteriocins/*metabolism/*pharmacology ; Biofilms/*growth & development ; Caenorhabditis elegans/microbiology ; Candida albicans/*drug effects/pathogenicity ; Candidiasis/microbiology/prevention & control ; Enterococcus faecalis/genetics/*metabolism ; Hyphae/*drug effects ; Macrophages/microbiology ; Mice ; Mice, Inbred BALB C ; Oropharynx/microbiology ; RAW 264.7 Cells ; Virulence ; }, abstract = {Enterococcus faecalis, a Gram-positive bacterium, and Candida albicans, a fungus, occupy overlapping niches as ubiquitous constituents of the gastrointestinal and oral microbiome. Both species also are among the most important and problematic, opportunistic nosocomial pathogens. Surprisingly, these two species antagonize each other's virulence in both nematode infection and in vitro biofilm models. We report here the identification of the E. faecalis bacteriocin, EntV, produced from the entV (ef1097) locus, as both necessary and sufficient for the reduction of C. albicans virulence and biofilm formation through the inhibition of hyphal formation, a critical virulence trait. A synthetic version of the mature 68-aa peptide potently blocks biofilm development on solid substrates in multiple media conditions and disrupts preformed biofilms, which are resistant to current antifungal agents. EntV[68] is protective in three fungal infection models at nanomolar or lower concentrations. First, nematodes treated with the peptide at 0.1 nM are completely resistant to killing by C. albicans The peptide also protects macrophages and augments their antifungal activity. Finally, EntV[68] reduces epithelial invasion, inflammation, and fungal burden in a murine model of oropharyngeal candidiasis. In all three models, the peptide greatly reduces the number of fungal cells present in the hyphal form. Despite these profound effects, EntV[68] has no effect on C. albicans viability, even in the presence of significant host-mimicking stresses. These findings demonstrate that EntV has potential as an antifungal agent that targets virulence rather than viability.}, } @article {pmid28395817, year = {2017}, author = {Araújo, PA and Machado, I and Meireles, A and Leiknes, T and Mergulhão, F and Melo, LF and Simões, M}, title = {Combination of selected enzymes with cetyltrimethylammonium bromide in biofilm inactivation, removal and regrowth.}, journal = {Food research international (Ottawa, Ont.)}, volume = {95}, number = {}, pages = {101-107}, doi = {10.1016/j.foodres.2017.02.016}, pmid = {28395817}, issn = {1873-7145}, mesh = {Anti-Infective Agents/pharmacology ; Biofilms/*drug effects ; Cetrimonium Compounds/*pharmacology ; Microbial Viability ; Peptide Hydrolases/pharmacology ; Pseudomonas fluorescens/*drug effects ; Stainless Steel ; alpha-Amylases/pharmacology ; }, abstract = {Enzymes are considered an innovative and environmentally friendly approach for biofilm control due to their lytic and dispersal activities. In this study, four enzymes (β-glucanase, α-amylase, lipase and protease) were tested separately and in combination with the quaternary ammonium compound cetyltrimethylammonium bromide (CTAB) to control flow-generated biofilms of Pseudomonas fluorescens. The four enzymes caused modest reduction of biofilm colony forming units (CFU). Protease, β-glucanase and α-amylase also caused modest biofilm removal. CTAB combined with either β-glucanase or α-amylase increased biofilm removal. Its combination with either β-glucanase or protease increased CFU reduction. However, CTAB-protease combination was antagonist in biofilm removal. Long-term effects in biofilm mass reduction were observed after protease exposure. In contrast, biofilms treated with β-glucanase were able to regrow significantly after exposure. Moreover, short-term respirometry tests with planktonic cells were performed to understand the effects of enzymes and their combination with CTAB on P. fluorescens viability. Protease and lipase demonstrated antimicrobial action, while α-amylase increased bacterial metabolic activity. The combination of CTAB with either protease or α-amylase was antagonistic, decreasing the antimicrobial action of CTAB. The overall results demonstrate a modest effect of the selected enzymes in biofilm control, either when applied alone or each one in combination with CTAB. Total biofilm removal or CFU reduction was not achieved and, in some cases, the use of enzymes antagonized the effects of CTAB. The results also propose that complementary tests, to characterize biofilm integrity and microbial viability, are required when someone is trying to assess the role of novel biocide - enzyme mixtures for effective biofilm control.}, } @article {pmid28394940, year = {2017}, author = {Ito, T and Ichinosawa, T and Shimizu, T}, title = {Streptococcal adhesin SspA/B analogue peptide inhibits adherence and impacts biofilm formation of Streptococcus mutans.}, journal = {PloS one}, volume = {12}, number = {4}, pages = {e0175483}, pmid = {28394940}, issn = {1932-6203}, mesh = {Adhesins, Bacterial/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Cyclophilins/drug effects/metabolism ; Durapatite ; Enzyme-Linked Immunosorbent Assay ; Humans ; Hydrogen-Ion Concentration ; Models, Biological ; Oligopeptides ; Polystyrenes ; Saliva/drug effects/microbiology ; Streptococcus mutans/*drug effects/*physiology ; Time Factors ; }, abstract = {Streptococcus mutans, the major causative agent of dental caries, adheres to tooth surfaces via the host salivary glycoprotein-340 (gp340). This adherence can be competitively inhibited by peptides derived from the SspA/B adhesins of Streptococcus gordonii, a human commensal microbe that competes for the same binding sites. Ssp(A4K-A11K), a double-lysine substituted SspA/B peptide analogue, has been shown to exhibit superior in vitro binding affinity for a gp340-derived peptide (SRCRP2), suggesting that Ssp(A4K-A11K) may be of clinical interest. In the present work, we tested the inhibitory effects of Ssp(A4K-A11K) on adherence and biofilm formation of S. mutans by reconstructing an artificial oral environment using saliva-coated polystyrene plates and hydroxyapatite disks. Bacterial adherence (adherence period: 1 h) was assessed by an enzyme-linked immunosorbent assay using biotinylated bacterial cells. Biofilm formation (periods: 8, 11, or 14 h) was assessed by staining and imaging of the sessile cells, or by recovering biofilm cells and plating for cell counts. The pH values of the culture media were measured as a biofilm acidogenicity indicator. Bactericidality was measured by loss of optical density during culturing in the presence of the peptide. We observed that 650 μM Ssp(A4K-A11K) significantly inhibited adherence of S. mutans to saliva-coated polystyrene; a similar effect was seen on bacterial affinity for SRCRP2. Ssp(A4K-A11K) had lesser effects on the adherence of commensal streptococci. Pretreatment of polystyrene and hydroxyapatite with 650 μM Ssp(A4K-A11K) significantly attenuated biofilm formation, whether tested with glucose- or sucrose-containing media. The SspA/B peptide's activity did not reflect bactericidality. Strikingly, pH in Ssp-treated 8-h (6.8 ± 0.06) and 11-h (5.5 ± 0.06) biofilms showed higher values than the critical pH. Thus, Ssp(A4K-A11K) acts by inhibiting bacterial adherence and cariogrnic biofilm formation. We further consider these results in the context of the safety, specificity, and stability properties of the Ssp(A4K-A11K) peptide.}, } @article {pmid28392782, year = {2017}, author = {Ansari, JM and Abraham, NM and Massaro, J and Murphy, K and Smith-Carpenter, J and Fikrig, E}, title = {Anti-Biofilm Activity of a Self-Aggregating Peptide against Streptococcus mutans.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {488}, pmid = {28392782}, issn = {1664-302X}, support = {R01 AI126033/AI/NIAID NIH HHS/United States ; }, abstract = {Streptococcus mutans is the primary agent of dental cavities, in large part due to its ability to adhere to teeth and create a molecular scaffold of glucan polysaccharides on the tooth surface. Disrupting the architecture of S. mutans biofilms could help undermine the establishment of biofilm communities that cause cavities and tooth decay. Here we present a synthetic peptide P1, derived from a tick antifreeze protein, which significantly reduces S. mutans biofilm formation. Incubating cells with this peptide decreased biofilm biomass by approximately 75% in both a crystal violet microplate assay and an in vitro tooth model using saliva-coated hydroxyapatite discs. Bacteria treated with peptide P1 formed irregular biofilms with disconnected aggregates of cells and exopolymeric matrix that readily detached from surfaces. Peptide P1 can bind directly to S. mutans cells but does not possess bactericidal activity. Anti-biofilm activity was correlated with peptide aggregation and β-sheet formation in solution, and alternative synthetic peptides of different lengths or charge distribution did not inhibit biofilms. This anti-biofilm peptide interferes with S. mutans biofilm formation and architecture, and may have future applications in preventing bacterial buildup on teeth.}, } @article {pmid28390280, year = {2017}, author = {Tang, K and Ooi, GTH and Litty, K and Sundmark, K and Kaarsholm, KMS and Sund, C and Kragelund, C and Christensson, M and Bester, K and Andersen, HR}, title = {Removal of pharmaceuticals in conventionally treated wastewater by a polishing moving bed biofilm reactor (MBBR) with intermittent feeding.}, journal = {Bioresource technology}, volume = {236}, number = {}, pages = {77-86}, doi = {10.1016/j.biortech.2017.03.159}, pmid = {28390280}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors ; Sewage ; Waste Disposal, Fluid ; *Wastewater ; }, abstract = {Previous studies have demonstrated that aerobic moving bed biofilm reactors (MBBRs) remove pharmaceuticals better than activated sludge. Thus we used a MBBR system to polish the effluent of an activated sludge wastewater treatment plant. To overcome that effluent contains insufficient organic matter to sustain enough biomass, the biofilm was intermittently fed with raw wastewater. The capacity of pharmaceutical degradation was investigated by spiking pharmaceuticals. Actual removal during treatment was assessed by sampling the inlets and outlets of reactors. The removal of the majority of pharmaceuticals was enhanced through the intermittent feeding of the MBBR. First-order rate constants for pharmaceutical removal, normalised to biomass, were significantly higher compared to other studies on activated sludge and suspended biofilms, especially for diclofenac, metoprolol and atenolol. Due to the intermittently feeding, degradation of diclofenac occurred with a half-life of only 2.1h and was thus much faster than any hitherto described wastewater bioreactor treatment.}, } @article {pmid28389992, year = {2018}, author = {Di Luca, M and Navari, E and Esin, S and Menichini, M and Barnini, S and Trampuz, A and Casani, A and Batoni, G}, title = {Detection of Biofilms in Biopsies from Chronic Rhinosinusitis Patients: In Vitro Biofilm Forming Ability and Antimicrobial Susceptibility Testing in Biofilm Mode of Growth of Isolated Bacteria.}, journal = {Advances in experimental medicine and biology}, volume = {1057}, number = {}, pages = {1-27}, doi = {10.1007/5584_2017_34}, pmid = {28389992}, issn = {0065-2598}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Biopsy ; Chronic Disease ; Humans ; Microbial Sensitivity Tests ; Quality of Life ; Rhinitis/*microbiology ; Sinusitis/*microbiology ; Staphylococcus epidermidis/isolation & purification ; }, abstract = {Chronic rhinosinusitis (CRS) is the most common illness among chronic disorders that remains poorly understood from a pathogenic standpoint and has a significant impact on patient quality of life, as well as healthcare costs. Despite being widespread, little is known about the etiology of the CRS. Recent evidence, showing the presence of biofilms within the paranasal sinuses, suggests a role for biofilm in the pathogenesis. To elucidate the role of biofilm in the pathogenesis of CRS, we assessed the presence of biofilm at the infection site and the ability of the aerobic flora isolated from CRS patients to form biofilm in vitro. For selected bacterial strains the susceptibility profiles to antibiotics in biofilm condition was also evaluated.Staphylococci represented the majority of the isolates obtained from the infection site, with S. epidermidis being the most frequently isolated species. Other isolates were represented by Enterobacteriaceae or by species present in the oral flora. Confocal laser scanning microscopy (CLSM) of the mucosal biopsies taken from patients with CRS revealed the presence of biofilm in the majority of the samples. Strains isolated from the specific infection site of the CRS patients were able to form biofilm in vitro at moderate or high levels, when tested in optimized conditions. No biofilm was observed by CLSM in the biopsies from control patients, although the same biopsies were positive for staphylococci in microbiological culture analysis. Drug-susceptibility tests demonstrated that the susceptibility profile of planktonic bacteria differs from that of sessile bacteria in biofilms.}, } @article {pmid28389920, year = {2017}, author = {Ivleva, NP and Kubryk, P and Niessner, R}, title = {Raman microspectroscopy, surface-enhanced Raman scattering microspectroscopy, and stable-isotope Raman microspectroscopy for biofilm characterization.}, journal = {Analytical and bioanalytical chemistry}, volume = {409}, number = {18}, pages = {4353-4375}, doi = {10.1007/s00216-017-0303-0}, pmid = {28389920}, issn = {1618-2650}, mesh = {Bacteria/*classification ; *Biofilms ; Spectrum Analysis, Raman/*methods ; }, abstract = {Biofilms represent the predominant form of microbial life on our planet. These aggregates of microorganisms, which are embedded in a matrix formed by extracellular polymeric substances, may colonize nearly all interfaces. Detailed knowledge of microorganisms enclosed in biofilms as well as of the chemical composition, structure, and functions of the complex biofilm matrix and their changes at different stages of the biofilm formation and under various physical and chemical conditions is relevant in different fields. Important research topics include the development and improvement of antibiotics and medical devices and the optimization of biocides, antifouling strategies, and biological wastewater treatment. Raman microspectroscopy is a capable and nondestructive tool that can provide detailed two-dimensional and three-dimensional chemical information about biofilm constituents with the spatial resolution of an optical microscope and without interference from water. However, the sensitivity of Raman microspectroscopy is rather limited, which hampers the applicability of Raman microspectroscopy especially at low biomass concentrations. Fortunately, the resonance Raman effect as well as surface-enhanced Raman scattering can help to overcome this drawback. Furthermore, the combination of Raman microspectroscopy with other microscopic techniques, mass spectrometry techniques, or particularly with stable-isotope techniques can provide comprehensive information on monospecies and multispecies biofilms. Here, an overview of different Raman microspectroscopic techniques, including resonance Raman microspectroscopy and surface-enhanced Raman scattering microspectroscopy, for in situ detection, visualization, identification, and chemical characterization of biofilms is given, and the main feasibilities and limitations of these techniques in biofilm research are presented. Future possibilities of and challenges for Raman microspectroscopy alone and in combination with other analytical techniques for characterization of complex biofilm matrices are discussed in a critical review. Graphical Abstract Applicability of Raman microspectroscopy for biofilm analysis.}, } @article {pmid28389154, year = {2017}, author = {Boopathi, S and Vashisth, R and Manoharan, P and Kandasamy, R and Sivakumar, N}, title = {Stigmatellin Y - An anti-biofilm compound from Bacillus subtilis BR4 possibly interferes in PQS-PqsR mediated quorum sensing system in Pseudomonas aeruginosa.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {27}, number = {10}, pages = {2113-2118}, doi = {10.1016/j.bmcl.2017.03.074}, pmid = {28389154}, issn = {1464-3405}, mesh = {Anti-Bacterial Agents/*chemistry/isolation & purification/metabolism/pharmacology ; Bacillus subtilis/*chemistry/metabolism ; Bacterial Proteins/*metabolism ; Binding Sites ; Chromatography, High Pressure Liquid ; Ligands ; Molecular Docking Simulation ; Polyenes/chemistry/isolation & purification/metabolism/pharmacology ; Protein Structure, Tertiary ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing/*drug effects ; Tandem Mass Spectrometry ; }, abstract = {Hitherto this is the first report pertaining to production of biofilm inhibitory compound(s) (BIC) from Bacillus subtilis BR4 against Pseudomonas aeruginosa (ATCC 27853) coupled with production optimization. In order to achieve this, combinations of media components were formulated by employing statistical tools such as Plackett-Burman analysis and central composite rotatable design (CCRD). It was evident that at 35mlL[-1] glycerol and 3.8gL[-1] casamino acid, anti-biofilm activity and production of extracellular protein significantly increased by 1.5-fold and 1.2-fold, respectively. These results corroborate that the combination of glycerol and casamino acid plays a key role in the production of BIC. Further, metabolic profiling of BIC was carried out using liquid chromatography/tandem mass spectrometry (LC-MS/MS) based on m/z value. The presence of Stigmatellin Y was predicted with monoisotopic neutral mass of 484.2825Da. In support of optimization study, higher production of BIC was confirmed in the optimized-media-grown BR4 (OPT-BR4) than in the ideal-media-grown BR4 (ID-BR4) by LC-MS/MS analysis. PqsR in P. aeruginosa is a potential target for anti-virulent therapy. Molecular docking study has revealed that Stigmatellin Y interacts with PqsR in the similar orientation like a cognate signal (PQS) and synthetic inhibitor. In addition, Stigmatellin Y was found to exhibit interaction with four more amino acid residues of PqsR to establish strong affinity. Stigmatellin Y thus might play a role of competitor for PQS to distract PQS-PqsR mediated communication in P. aeruginosa. The present investigation thus paves new avenues to develop anti-Pseudomonas virulent therapy.}, } @article {pmid28387883, year = {2017}, author = {Casalinuovo, IA and Sorge, R and Bonelli, G and Di Francesco, P}, title = {Evaluation of the antifungal effect of EDTA, a metal chelator agent, on Candida albicans biofilm.}, journal = {European review for medical and pharmacological sciences}, volume = {21}, number = {6}, pages = {1413-1420}, pmid = {28387883}, issn = {2284-0729}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Chelating Agents/pharmacology ; Edetic Acid/*pharmacology ; Fluconazole/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {OBJECTIVE: Candida albicans biofilm is frequently found on artificial surfaces and the infections related to biofilm are difficult to eliminate, as they require the removal of artificial devices and treatment with antifungal drugs. Nowadays, fungal growth in biofilms is difficult to eradicate with conventional antifungal drugs such as fluconazole. Among chelating agents, disodium salt-Ethylene Diamine Tetraacetic Acid (EDTA) is known to have antifungal activity. In this study, we examined the in vitro activity of the EDTA and the antifungal drug fluconazole against C. albicans mature biofilm.

MATERIALS AND METHODS: C. albicans ATCC 20191, fluconazole-susceptible strain, was grown at an inoculum starter of 1 x 106 cells/ml for 72 h in 24-well microtiter plates and was further treated for 24 h with EDTA and/or fluconazole. Antifungal activities in biofilms were expressed as reduction in optical density (OD) determined by a 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) colorimetric assay and compared to untreated biofilms.

RESULTS: Colorimetric readings revealed that EDTA alone (at 25 and 2.5 mM) significantly reduced fungal metabolic activity in preformed biofilms. Also, EDTA combined with fluconazole significantly reduced the growth of biofilm when compared to biofilm treated with fluconazole alone (at 25 and 2.5 µg/ml).

CONCLUSIONS: Our data suggest that the employment of EDTA or other chemicals destabilizers of the biofilm matrix, in combination with antifungal drugs, could lead to the development of new strategies for the management of infections associated to Candida biofilm. Another relevant result of our study suggests that the initial cell concentration, probably through mechanisms of quorum sensing, affects the cellular viability during the process of biofilm formation.}, } @article {pmid28387799, year = {2017}, author = {Petrovich, M and Wu, CY and Rosenthal, A and Chen, KF and Packman, AI and Wells, GF}, title = {Nitrosomonas europaea biofilm formation is enhanced by Pseudomonas aeruginosa.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {5}, pages = {}, doi = {10.1093/femsec/fix047}, pmid = {28387799}, issn = {1574-6941}, mesh = {Ammonia/metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Coculture Techniques ; Microbial Interactions/*physiology ; Nitrosomonas europaea/*growth & development ; Oxidation-Reduction ; Pseudomonas aeruginosa/*growth & development ; Wastewater/microbiology ; Water Purification/methods ; }, abstract = {Biofilms are useful in biotechnology applications such as wastewater treatment, where aggregation of cells on surfaces can increase retention of slow-growing organisms such as ammonia-oxidizing bacteria (AOB). The formation and morphological development of polymicrobial biofilms including AOB are not thoroughly understood. Here, we investigated the formation of Nitrosomonas europaea AOB biofilms in flow cell systems. Nitrosomonas europaea developed substantially greater biovolume in co-culture with heterotrophic Pseudomonas aeruginosa than when cultured alone. In single-species biofilms, N. europaea formed thin, dispersed layers of cells. Contrastingly, when N. europaea was added to flow cells containing pre-established P. aeruginosa biofilms, N. europaea associated closely with P. aeruginosa, resulting in dual-species clusters with greater quantities of N. europaea. These results indicate that P. aeruginosa enhances the formation of N. europaea in biofilms. This favorable association of N. europaea with heterotrophic biofilms is expected to facilitate development of improved strategies for retention of N. europaea and other slow-growing AOB in engineered bioreactors.}, } @article {pmid28386730, year = {2017}, author = {Inoue, D and Kabata, T and Ohtani, K and Kajino, Y and Shirai, T and Tsuchiya, H}, title = {Inhibition of biofilm formation on iodine-supported titanium implants.}, journal = {International orthopaedics}, volume = {41}, number = {6}, pages = {1093-1099}, pmid = {28386730}, issn = {1432-5195}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Iodine/*pharmacology ; Male ; Microscopy, Electron, Scanning ; Prostheses and Implants/*microbiology ; Rats ; Rats, Sprague-Dawley ; Staphylococcus aureus/*drug effects ; Surface Properties ; Titanium/*pharmacology ; }, abstract = {PURPOSE: We have developed iodine-supported titanium implants that suppress microbial activities and conducted in vivo and in vitro studies to determine their antimicrobial properties.

METHODS: The implants were Ti-6Al-4 V titanium implants either untreated (Ti), treated with oxide film on the Ti surface by anodization (Ti-O), or treated with an iodine coating on oxidation film (Ti-I). The strain of bacteria used in this study was Gram-positive Staphylococcus aureus strain ATCC 25923. We analyzed the antibacterial attachment effects in vivo by using rats. The attachment bacteria on the implant surface were evaluated using a spread-plate method assay. A biofilm study was performed in vitro. The biofilm formed after bacterial attachment was qualitatively studied with fluorescence microscopy (FM) and scanning electron microscopy (SEM). Also, the formed biofilm was quantitatively studied with a spread-plate method assay.

RESULTS: In vivo analysis of antimicrobial attachment effects showed that the mean viable bacterial number was significantly lower on Ti-I than Ti or Ti-O surfaces. In the in vitro biofilm study, FM and SEM images showed thick and mature biofilm formation on Ti and Ti-O and thin, small biofilm formation on Ti-I. A quantitative biofilm analysis found a significant difference in the number of viable bacteria between Ti-I and Ti or Ti-O.

CONCLUSIONS: This study showed that iodine-supported implants have a good antibacterial attachment effect and inhibit biofilm formation and growth. Iodine-supported implants may have great potential as innovative antibacterial implants that can prevent implant related infection in orthopaedic surgery.}, } @article {pmid28386534, year = {2017}, author = {Prateeksha, and Singh, BR and Shoeb, M and Sharma, S and Naqvi, AH and Gupta, VK and Singh, BN}, title = {Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {93}, pmid = {28386534}, issn = {2235-2988}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Proteins/chemistry/metabolism ; Biofilms/*drug effects ; *Honey ; Mice ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Conformation ; *Nanocomposites/chemistry/ultrastructure ; Phytochemicals/*chemistry/*pharmacology ; Polyphenols/chemistry/pharmacology ; Protein Binding ; Pseudomonas Infections/microbiology/mortality ; Pseudomonas aeruginosa/*drug effects/*physiology ; Quorum Sensing/*drug effects ; *Selenium ; Trans-Activators/chemistry/metabolism ; Virulence/drug effects ; }, abstract = {Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS), a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors) and polyphenols of honey (HP) for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery.}, } @article {pmid28386254, year = {2017}, author = {Fontaine, BM and Nelson, K and Lyles, JT and Jariwala, PB and García-Rodriguez, JM and Quave, CL and Weinert, EE}, title = {Identification of Ellagic Acid Rhamnoside as a Bioactive Component of a Complex Botanical Extract with Anti-biofilm Activity.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {496}, pmid = {28386254}, issn = {1664-302X}, support = {T34 GM008156/GM/NIGMS NIH HHS/United States ; }, abstract = {Staphylococcus aureus is a leading cause of hospital-acquired infections. It is listed among the top "serious threats" to human health in the USA, due in large part to rising rates of resistance. Many S. aureus infections are recalcitrant to antibiotic therapy due to their ability to form a biofilm, which acts not only as a physical barrier to antibiotics and the immune system, but results in differences in metabolism that further restricts antibiotic efficacy. Development of a modular strategy to synthesize a library of phenolic glycosides allowed for bioactivity testing and identification of anti-biofilm compounds within an extract of the elmleaf blackberry (Rubus ulmifolius). Two ellagic acid (EA) derivatives, EA xyloside and EA rhamnoside, have been identified as components of the Rubus extract. In addition, EA rhamnoside has been identified as an inhibitor of biofilm formation, with activity comparable to the complex extract 220D-F2 (composed of a mixture of EA glycosides), and confirmed by confocal laser scanning microscopy analyses.}, } @article {pmid28385217, year = {2017}, author = {Laskar, K and Faisal, SM and Rauf, A and Ahmed, A and Owais, M}, title = {Undec-10-enoic acid functionalized chitosan based novel nano-conjugate: An enhanced anti-bacterial/biofilm and anti-cancer potential.}, journal = {Carbohydrate polymers}, volume = {166}, number = {}, pages = {14-23}, doi = {10.1016/j.carbpol.2017.02.082}, pmid = {28385217}, issn = {1879-1344}, mesh = {Anti-Bacterial Agents/*pharmacology ; Antineoplastic Agents/*pharmacology ; Bacteria ; Biofilms/*drug effects ; Cell Line, Tumor ; Chitosan/*chemistry ; Humans ; Lactalbumin ; *Nanoconjugates ; Oleic Acid ; Undecylenic Acids/*chemistry ; }, abstract = {Fatty acid functionalized chitosan conjugates are of great interest in cancer therapeutics because of its internalization through receptor mediated endocytosis into the cancer cells. Keeping the above fact into consideration, herein we synthesized the undec-10-enoic acid functionalized chitosan based undecyl-chitosan (U-CS) nano-bioconjugate with the use of DCC as a coupling agent. The U-CS conjugate synthesized was confirmed and characterized by FTIR, [1]H NMR, TGA, XRD, SEM and TEM analysis. Generally, it is well established that conjugates of oleic acid with human Alpha-lactalbumin (HAMLET) induce cytotoxicity in the altered cells, but not in healthy cells. To check our presumptions, anti-bacterial and anti-cancer potential of U-CS was evaluated against bacterial pathogens (Gram +ve and Gram -ve) and human cancer cell lines (HeLa, MDA-MB-231 and Hep3B). The results of our study clearly revealed that conjugate showed enhance anti-bacterial, anti-biofilm as well as anti-cancer efficacy as compared to pure and free form of the chitosan.}, } @article {pmid28381059, year = {2017}, author = {Zhong, N and Zhao, M and Zhong, L and Li, S and Luo, B and Tang, B and Song, T and Shi, S and Hu, X and Xin, X and Wu, R and Cen, Y and Wang, Z}, title = {Luminous exothermic hollow optical elements for enhancement of biofilm growth and activity.}, journal = {Optics express}, volume = {25}, number = {6}, pages = {5876-5890}, doi = {10.1364/OE.25.005876}, pmid = {28381059}, issn = {1094-4087}, abstract = {In this work, we present a luminous-exothermic hollow optical element (LEHOE) that performs spectral beam splitting in the visible spectral range for the enhancement of biofilm growth and activity. The LEHOE is composed of a four-layer structure with a fiber core (air), cladding (SiO2), coating I (LaB6 film), and coating II (SiO2-Agarose-Medium film). To clarify the physical, optical and photothermal conversion properties of the LEHOE, we determined the surface morphology and composition of the coating materials, and examined the luminous intensity and heating rate at the LEHOE surface. The biofilm activity on the biocompatible LEHOE is far greater than that of commercial fibers, and the biofilm weight on the LEHOE is 4.5 × that of the uncoated hollow optical element.}, } @article {pmid28379244, year = {2017}, author = {Dranguet, P and Cosio, C and Le Faucheur, S and Hug Peter, D and Loizeau, JL and Ungureanu, VG and Slaveykova, VI}, title = {Biofilm composition in the Olt River (Romania) reservoirs impacted by a chlor-alkali production plant.}, journal = {Environmental science. Processes & impacts}, volume = {19}, number = {5}, pages = {687-695}, doi = {10.1039/c7em00033b}, pmid = {28379244}, issn = {2050-7895}, mesh = {Alkalies/chemistry ; Biodiversity ; Biofilms/drug effects/*growth & development ; *Chemical Industry ; Chlorides/chemistry ; Mercury/analysis/*toxicity ; *Rivers/chemistry/microbiology ; Romania ; Wastewater/analysis/microbiology/toxicity ; *Water Microbiology ; Water Pollutants, Chemical/analysis/*toxicity ; Water Quality ; Water Resources ; }, abstract = {Freshwater biofilms can be useful indicators of water quality and offer the possibility to assess contaminant effects at the community level. The present field study examines the effects of chlor-alkali plant effluents on the community composition of biofilms grown in the Olt River (Romania) reservoirs. The relationship between ambient water quality variables and community composition alterations was explored. Amplicon sequencing revealed a significant modification of the composition of microalgal, bacterial and fungal communities in the biofilms collected in the impacted reservoirs in comparison with those living in the uncontaminated control reservoir. The abundance corrected Simpson index showed lower richness and diversity in biofilms collected in the impacted reservoirs than in the control reservoir. The biofilm bacterial communities of the impacted reservoirs were characterized by the contaminant-tolerant Cyanobacteria and Bacteroidetes, whereas microalgal communities were predominantly composed of Bacillariophyta and fungal communities of Lecanoromycetes and Paraglomycetes. A principal component analysis revealed that major contaminants present in the waste water of the chlor-alkali production plant, i.e. Na[+], Ca[2+], Cl[-] and Hg, were correlated with the alteration of biofilm community composition in the impacted reservoirs. However, the biofilm composition was also influenced by water quality variables such as NO3[-], SO4[2-], DOC and Zn from unknown sources. The results of the present study imply that, even when below the environmental quality standards, typical contaminants of chlor-alkali plant releases may affect biofilm composition and that their impacts on the microbial biodiversity might be currently overlooked.}, } @article {pmid28378343, year = {2017}, author = {Taha, M and Culibrk, B and Kalab, M and Schubert, P and Yi, QL and Goodrich, R and Ramirez-Arcos, S}, title = {Efficiency of riboflavin and ultraviolet light treatment against high levels of biofilm-derived Staphylococcus epidermidis in buffy coat platelet concentrates.}, journal = {Vox sanguinis}, volume = {112}, number = {5}, pages = {408-416}, doi = {10.1111/vox.12519}, pmid = {28378343}, issn = {1423-0410}, mesh = {*Biofilms ; Blood Buffy Coat/microbiology ; Blood Platelets/*microbiology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability ; Photosensitizing Agents/*pharmacology ; Riboflavin/*pharmacology ; Staphylococcus epidermidis/drug effects/*physiology/radiation effects ; Ultraviolet Rays ; }, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus epidermidis forms surface-attached aggregates (biofilms) in platelet concentrates (PCs), which are linked to missed detection during PC screening. This study was aimed at evaluating the efficacy of riboflavin-UV treatment to inactivate S. epidermidis biofilms in buffy coat (BC) PCs.

MATERIALS AND METHODS: Biofilm and non-biofilm cells from S. epidermidis ST-10002 and S. epidermidis AZ-66 were individually inoculated into whole blood (WB) units (~10[6] colony-forming units (CFU)/ml) (N = 4-5). One spiked and three unspiked WB units were processed to produce a BC-PC pool. Riboflavin was added to the pool which was then split into two bags: one for UV treatment and the second was untreated. Bacterial counts were determined before and after treatment. In vitro PC quality was assessed by flow cytometry and dynamic light scattering.

RESULTS: Bacterial counts were reduced during BC-PC production from ~10[6] CFU/ml in WB to 10[3] -10[4] CFU/ml in PCs (P < 0·0001). Riboflavin-UV treatment resulted in significantly higher reduction of S. epidermidis AZ-66 than strain ST-10002 (≥3·5 log reduction and 2·6-2·8 log reduction, respectively, P < 0·0001). Remaining bacteria post-treatment were able to proliferate in PCs. No differences in S. epidermidis inactivation were observed in PCs produced from WB inoculated with biofilm or non-biofilm cells (P > 0·05). Platelet activation was enhanced in PCs produced with WB inoculated with biofilms compared to non-biofilm cells (P < 0·05).

CONCLUSION: Riboflavin-UV treatment was similarly efficacious in PCs produced from WB inoculated with S. epidermidis biofilm or non-biofilm cells. Levels of biofilm-derived S. epidermidis ≥10[3] CFU/ml were not completely inactivated; however, further testing is necessary with lower (real-life) bacterial levels.}, } @article {pmid28377931, year = {2017}, author = {Fu, B and Wu, Q and Dang, M and Bai, D and Guo, Q and Shen, L and Duan, K}, title = {Inhibition of Pseudomonas aeruginosa Biofilm Formation by Traditional Chinese Medicinal Herb Herba patriniae.}, journal = {BioMed research international}, volume = {2017}, number = {}, pages = {9584703}, pmid = {28377931}, issn = {2314-6141}, mesh = {Anti-Bacterial Agents/administration & dosage/chemistry ; Biofilms/*drug effects ; Humans ; Medicine, Chinese Traditional/methods ; Patrinia/chemistry ; Plant Extracts/*administration & dosage/chemistry ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; }, abstract = {New antimicrobial agents are urgently needed to treat infections caused by drug-resistant pathogens and by pathogens capable of persisting in biofilms. The aim of this study was to identify traditional Chinese herbs that could inhibit biofilm formation of Pseudomonas aeruginosa, an important human pathogen that causes serious and difficult-to-treat infections in humans. A luxCDABE-based reporter system was constructed to monitor the expression of six key biofilm-associated genes in P. aeruginosa. The reporters were used to screen a library of 36 herb extracts for inhibitory properties against these genes. The results obtained indicated that the extract of Herba patriniae displayed significant inhibitory effect on almost all of these biofilm-associated genes. Quantitative analysis showed that H. patriniae extract was able to significantly reduce the biofilm formation and dramatically altered the structure of the mature biofilms of P. aeruginosa. Further studies showed H. patriniae extract decreased exopolysaccharide production by P. aeruginosa and promoted its swarming motility, two features disparately associated with biofilm formation. These results provided a potential mechanism for the use of H. patriniae to treat bacterial infections by traditional Chinese medicines and revealed a promising candidate for exploration of new drugs against P. aeruginosa biofilm-associated infections.}, } @article {pmid28377634, year = {2017}, author = {Wang, J and Yao, QF and Amin, M and Nong, XH and Zhang, XY and Qi, SH}, title = {Penicillenols from a deep-sea fungus Aspergillus restrictus inhibit Candida albicans biofilm formation and hyphal growth.}, journal = {The Journal of antibiotics}, volume = {70}, number = {6}, pages = {763-770}, pmid = {28377634}, issn = {1881-1469}, mesh = {Amphotericin B/administration & dosage/pharmacology ; Antifungal Agents/administration & dosage/isolation & purification/*pharmacology ; Aspergillus/*metabolism ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Drug Synergism ; Pyrrolidinones/administration & dosage/isolation & purification/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Penicillenols (A1, A2, B1, B2, C1 and C2) were isolated from Aspergillus restrictus DFFSCS006, and could differentially inhibit biofilm formation and eradicate pre-developed biofilms of Candida albicans. Their structure-bioactivity relationships suggested that the saturation of hydrocarbon chain at C-8, R-configuration of C-5 and trans-configuration of the double bond between C-5 and C-6 of pyrrolidine-2,4-dione unit were important for their anti-biofilm activities. Penicillenols A2 and B1 slowed the hyphal growth and suppressed the transcripts of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4. Moreover, penicillenols A2 and B1 were found to act synergistically with amphotericin B against C. albicans biofilm formation.}, } @article {pmid28377623, year = {2017}, author = {Zhao, R and Song, Y and Dai, Q and Kang, Y and Pan, J and Zhu, L and Zhang, L and Wang, Y and Shen, X}, title = {A starvation-induced regulator, RovM, acts as a switch for planktonic/biofilm state transition in Yersinia pseudotuberculosis.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {639}, pmid = {28377623}, issn = {2045-2322}, mesh = {Bacterial Proteins/*genetics/*metabolism ; Base Sequence ; Binding Sites ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Plankton/*growth & development ; Promoter Regions, Genetic ; Protein Binding ; Transcriptional Activation ; Virulence ; Yersinia pseudotuberculosis/*physiology/ultrastructure ; }, abstract = {The transition between the planktonic state and the biofilm-associated state is a key developmental decision for pathogenic bacteria. Biofilm formation by Yersinia pestis is regulated by hmsHFRS genes (β-1, 6-N-acetyl-D-glucosamine synthesis operon) in its flea vector and in vitro. However, the mechanism of biofilm formation in Yersinia pseudotuberculosis remains elusive. In this study, we demonstrate that the LysR-type regulator RovM inversely regulates biofilm formation and motility in Y. pseudotuberculosis by acting as a transcriptional regulator of these two functions. RovM is strongly induced during growth in minimal media but strongly repressed in complex media. On one hand, RovM enhances bacterial motility by activating the expression of FlhDC, the master regulator of flagellar genes, via the recognition of an operator upstream of the flhDC promoter. On the other hand, RovM represses β-GlcNAc production under nutrition-limited conditions, negatively regulating hmsHFRS expression by directly binding to the -35 element of its promoter. Compared to wild-type bacteria, the rovM mutant established denser biofilms and caused more extensive mortality in mice and silkworm larvae. These results indicate that RovM acts as a molecular switch to coordinate the expression of genes involved in biofilm formation and motility in response to the availability of nutrients.}, } @article {pmid28376271, year = {2017}, author = {}, title = {The Editor recommends this issue's article to the reader: Relationship among a amylase and carbonic anhydrase VI in saliva, visible biofilm, and early childhood caries: a longitudinal study.}, journal = {International journal of paediatric dentistry}, volume = {27}, number = {3}, pages = {153}, doi = {10.1111/ipd.12303}, pmid = {28376271}, issn = {1365-263X}, mesh = {*Biofilms ; Dental Caries/*prevention & control ; Humans ; Saliva/*physiology ; }, } @article {pmid28376133, year = {2017}, author = {Gabriel, I and Rychłowski, M}, title = {Consequences of lysine auxotrophy for Candida albicans adherence and biofilm formation.}, journal = {Acta biochimica Polonica}, volume = {64}, number = {2}, pages = {323-329}, doi = {10.18388/abp.2016_1427}, pmid = {28376133}, issn = {1734-154X}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*growth & development/pathogenicity ; Cell Adhesion/genetics ; Epithelial Cells/metabolism ; Gene Expression Regulation, Fungal ; Humans ; Lysine/analogs & derivatives/biosynthesis/genetics/*metabolism ; Mice ; NIH 3T3 Cells ; }, abstract = {A number of factors are known to be involved in Candida albicans virulence, although biofilm development on the surfaces of indwelling medical devices is considered to promote superficial or systemic disease. Based on previously reported up-regulation of saccharopine and acetyllysine in biofilm cells and activation of the lysine biosynthesis/degradation pathway, we investigated the consequences of Candida albicans lysine auxotrophy on adhesion to host tissues and biofilm formation. Our data indicate that mutant strains lysΔ21/lysΔ22, defective in homocitrate synthase, and lysΔ4, defective in homoaconitase activity (the first two α-aminoadipate pathway enzymes), are able to adhere to mouse embryonic fibroblast cells (cell line NIH/3T3) to the same extent as a control strain SC5314. On the other hand, the auxotrophic mutant strains' development on mouse fibroblast monolayers was significantly reduced up to 5 h post infection. Although invasion into human-derived oral epithelial cells was unaltered, both mutant strains formed a significantly different biofilm architecture and demonstrated diminished viability during long term biofilm propagation.}, } @article {pmid28375804, year = {2017}, author = {Vazales, B}, title = {Commentary on "Effect of the endOclear[®] Device on Biofilm in Endotracheal Tubes".}, journal = {Surgical infections}, volume = {18}, number = {5}, pages = {641-642}, doi = {10.1089/sur.2017.032}, pmid = {28375804}, issn = {1557-8674}, mesh = {*Biofilms ; Humans ; *Intubation, Intratracheal ; Pneumonia, Ventilator-Associated ; }, } @article {pmid28374996, year = {2017}, author = {Wells, GF and Shi, Y and Laureni, M and Rosenthal, A and Szivák, I and Weissbrodt, DG and Joss, A and Buergmann, H and Johnson, DR and Morgenroth, E}, title = {Comparing the Resistance, Resilience, and Stability of Replicate Moving Bed Biofilm and Suspended Growth Combined Nitritation-Anammox Reactors.}, journal = {Environmental science & technology}, volume = {51}, number = {9}, pages = {5108-5117}, doi = {10.1021/acs.est.6b05878}, pmid = {28374996}, issn = {1520-5851}, mesh = {*Biofilms ; *Bioreactors ; In Situ Hybridization, Fluorescence ; Nitrification ; Nitrogen ; Wastewater ; }, abstract = {Combined partial nitritation-anammox (PN/A) systems are increasingly being employed for sustainable removal of nitrogen from wastewater, but process instabilities present ongoing challenges for practitioners. The goal of this study was to elucidate differences in process stability between PN/A process variations employing two distinct aggregate types: biofilm [in moving bed biofilm reactors (MBBRs)] and suspended growth biomass. Triplicate reactors for each process variation were studied under baseline conditions and in response to a series of transient perturbations. MBBRs displayed elevated NH4[+] removal rates relative to those of suspended growth counterparts over six months of unperturbed baseline operation but also exhibited significantly greater variability in performance. Transient perturbations led to strikingly divergent yet reproducible behavior in biofilm versus suspended growth systems. A temperature perturbation prompted a sharp reduction in NH4[+] removal rates with no accumulation of NO2[-] and rapid recovery in MBBRs, compared to a similar reduction in NH4[+] removal rates but a high level of accumulation of NO2[-] in suspended growth reactors. Pulse additions of a nitrification inhibitor (allylthiourea) prompted only moderate declines in performance in suspended growth reactors compared to sharp decreases in NH4[+] removal rates in MBBRs. Quantitative fluorescence in situ hybridization demonstrated a significant enrichment of anammox in MBBRs compared to suspended growth reactors, and conversely a proportionally higher AOB abundance in suspended growth reactors. Overall, MBBRs displayed significantly increased susceptibility to transient perturbations employed in this study compared to that of suspended growth counterparts (stability parameter), including significantly longer recovery times (resilience). No significant difference in the maximal impact of perturbations (resistance) was apparent. Taken together, our results suggest that aggregate architecture (biofilm vs suspended growth) in PN/A processes exerts an unexpectedly strong influence on process stability.}, } @article {pmid28374425, year = {2017}, author = {Ullah, N and Wang, X and Chen, L and Xu, X and Li, Z and Feng, X}, title = {Influence of biofilm surface layer protein A (BslA) on the gel structure of myofibril protein from chicken breast.}, journal = {Journal of the science of food and agriculture}, volume = {97}, number = {14}, pages = {4712-4720}, doi = {10.1002/jsfa.8339}, pmid = {28374425}, issn = {1097-0010}, mesh = {Animals ; Bacterial Proteins/*pharmacology ; *Biofilms ; Calorimetry, Differential Scanning ; Chemical Phenomena ; *Chickens ; Electrophoresis, Polyacrylamide Gel ; Gels/*chemistry ; Hydrophobic and Hydrophilic Interactions ; Meat/analysis ; Microscopy, Electron, Scanning ; Muscle Proteins/*chemistry/drug effects ; Myofibrils/*chemistry ; Rheology ; Water/analysis ; }, abstract = {BACKGROUND: Different techniques have been applied to alter myofibril protein (MP) structure, which further promotes protein-protein interactions and influencing the MP gelling characteristics. Influence of BslA from natto food (protein concentration, 30 mg mL[-1] ; at 0.001, 0.005, 0.01, 0.05 and 0.1 g kg[-1]) on the characteristics of MP gel of chicken breast was investigated.

RESULTS: Results show that cooking loss significantly (P < 0.05) decreased with increased percentage of BslA. Hardness of MP gel did not significantly change at 0.01 g kg[-1] BslA. Differential scanning calorimetry disclosed that MP was modified by the addition of BslA. Moreover, BslA produced a high value of storage modulus (G') and low value of phase angle (tan δ) during heating, especially at 0.01 g kg[-1] . Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis proved the formation of higher-molecular-weight polymers by developing non-disulfide covalent bonds between MP at 0.01 g kg[-1] BslA. Surface hydrophobicity of the MP gel was decreased with increased percentage of BslA. Scanning electron microscopy confirmed the increasing number of uniform cavities of MP gel with the increased percentage of BslA.

CONCLUSION: Addition of 0.01 g kg[-1] BslA significantly improved the water holding capacity and rheological properties of MP by developing non-disulfide covalent bonds. © 2017 Society of Chemical Industry.}, } @article {pmid28374061, year = {2017}, author = {Briand, JF and Barani, A and Garnier, C and Réhel, K and Urvois, F and LePoupon, C and Bouchez, A and Debroas, D and Bressy, C}, title = {Spatio-Temporal Variations of Marine Biofilm Communities Colonizing Artificial Substrata Including Antifouling Coatings in Contrasted French Coastal Environments.}, journal = {Microbial ecology}, volume = {74}, number = {3}, pages = {585-598}, pmid = {28374061}, issn = {1432-184X}, mesh = {Atlantic Ocean ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Biofouling/prevention & control ; Diatoms/*physiology ; Flow Cytometry ; France ; Mediterranean Sea ; Seasons ; Seawater/*microbiology ; Sequence Analysis, DNA ; }, abstract = {Surface colonization in seawater first corresponds to the selection of specific microbial biofilm communities. By coupling flow cytometry, microscopy and high throughput sequencing (HTS, 454 pyrosequencing) with artificial surfaces and environmental analyses, we intend to identify the contribution of biofilm community drivers at two contrasted French sites, one temperate and eutrophic (Lorient, Atlantic coast) and the other at a mesotrophic but highly contaminated bay (Toulon, North-Western Mediterranean Sea). Microbial communities were shaped by high temperatures, salinity and lead at Toulon by but nutrients and DOC at Lorient. Coatings including pyrithione exhibited a significant decrease of their microbial densities except for nanoeukaryotes. Clustering of communities was mainly based on the surface type and secondly the site, whereas seasons appeared of less importance. The in-depth HTS revealed that γ- and α-proteobacteria, but also Bacteroidetes, dominated highly diversified bacterial communities with a relative low β-diversity. Sensitivity to biocides released by the tested antifouling coatings could be noticed at different taxonomic levels: the percentage of Bacteroidetes overall decreased with the presence of pyrithione, whereas the α/γ-proteobacteria ratio decreased at Toulon when increased at Lorient. Small diatom cells (Amphora and Navicula spp.) dominated on all surfaces, whereas site-specific sub-dominant taxa appeared clearly more sensitive to biocides. This overall approach exhibited the critical significance of surface characteristics in biofilm community shaping.}, } @article {pmid28373143, year = {2017}, author = {Sun, M and Dong, J and Xia, Y and Shu, R}, title = {Antibacterial activities of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) against planktonic and biofilm growing Streptococcus mutans.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {212-218}, doi = {10.1016/j.micpath.2017.03.040}, pmid = {28373143}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects/*growth & development ; Colony Count, Microbial ; Docosahexaenoic Acids/administration & dosage/chemistry/*pharmacology ; Eicosapentaenoic Acid/administration & dosage/chemistry/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects/genetics ; Genes, Bacterial/genetics ; Microbial Sensitivity Tests/methods ; Microbial Viability/drug effects ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; RNA, Ribosomal, 16S/genetics ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*drug effects/genetics/growth & development/metabolism ; Virulence Factors/genetics ; }, abstract = {The aim of this study was to evaluate the potential antibacterial activities of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) against planktonic and biofilm modes of Streptococcus mutans (S. mutans). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The effects on planktonic growth and biofilm metabolic activity were evaluated by growth curve determination and MTT assay, respectively. Then, colony forming unit (CFU) counting, scanning electron microscopy (SEM) and real-time PCR were performed to further investigate the actions of DHA and EPA on exponential phase-S. mutans. Confocal laser scanning microscopy (CLSM) was used to detect the influences on mature biofilms. The MICs of DHA and EPA against S. mutans were 100 μM and 50 μM, respectively; the MBC of both compounds was 100 μM. In the presence of 12.5 μM-100 μM DHA or EPA, the planktonic growth and biofilm metabolic activity were reduced in varying degrees. For exponential-phase S. mutans, the viable counts, the bacterial membranes and the biofilm-associated gene expression were damaged by 100 μM DHA or EPA treatment. For 1-day-old biofilms, the thickness was decreased and the proportion of membrane-damaged bacteria was increased in the presence of 100 μM DHA or EPA. These results indicated that, DHA and EPA possessed antibacterial activities against planktonic and biofilm growing S. mutans.}, } @article {pmid28372810, year = {2017}, author = {Lin, NJ}, title = {Biofilm over teeth and restorations: What do we need to know?.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {33}, number = {6}, pages = {667-680}, doi = {10.1016/j.dental.2017.03.003}, pmid = {28372810}, issn = {1879-0097}, mesh = {*Biofilms ; Dental Materials ; *Dental Restoration, Permanent ; Humans ; *Tooth ; }, abstract = {OBJECTIVE: The goal of this manuscript is to provide an overview of biofilm attributes and measurement approaches in the context of studying biofilms on tooth and dental material surfaces to improve oral health.

METHODS: A historical perspective and terminology are presented, followed by a general description of the complexity of oral biofilms. Then, an approach to grouping measurable biofilm properties is presented and considered in relation to biofilm-material interactions and material design strategies to alter biofilms. Finally, the need for measurement assurance in biofilm and biofilm-materials research is discussed.

RESULTS: Biofilms are highly heterogeneous communities that are challenging to quantify. Their characteristics can be broadly categorized into constituents (identity), quantity, structure, and function. These attributes can be measured over time and in response to substrates and external stimuli. Selecting the biofilm attribute(s) of interest and appropriate measurement methods will depend on the application and, in the case of antimicrobial therapies, the strategic approach and expected mechanism of action. To provide measurement assurance, community accepted protocols and guidelines for minimum data and metadata should be established and broadly applied. Consensus standards may help to streamline testing and demonstration of product claims.

SIGNIFICANCE: Understanding oral biofilms and their interactions with tooth and dental material surfaces holds great promise for enabling improvements in oral and overall human health. Both substrate and biofilm properties should be considered to develop a more thorough understanding of the system.}, } @article {pmid28372761, year = {2017}, author = {Zheng, Z and Li, J and Ma, J and Du, J and Wang, F and Bian, W and Zhang, Y and Zhao, B}, title = {Inhibition factors and Kinetic model for ammonium inhibition on the anammox process of the SNAD biofilm.}, journal = {Journal of environmental sciences (China)}, volume = {53}, number = {}, pages = {60-67}, doi = {10.1016/j.jes.2016.05.015}, pmid = {28372761}, issn = {1001-0742}, mesh = {Ammonia ; Ammonium Compounds/*metabolism ; Anaerobiosis ; Biodegradation, Environmental ; *Biofilms ; Bioreactors ; Chemoautotrophic Growth ; Denitrification ; Kinetics ; Models, Theoretical ; Nitrification ; Waste Disposal, Fluid ; }, abstract = {The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH4[+]-N removal rate of anammox process remained 87.4% of the maximum rate with the NO2[-]-N concentration of 100mg/L. Based on the results of Haldane model, no obvious difference in kinetic coefficients was observed under high or low free ammonia (FA) conditions, indicating that ammonium rather than FA was the true inhibitor for anammox process of SNAD biofilm. With the pH value of 7.0, the rmax, Ks and KI of ammonium were 0.209kg NO2[-]-N/kg VSS/day, 9.5mg/L and 422mg/L, respectively. The suitable pH ranges for anammox process were 5.0 to 9.0. These results indicate that the SNAD biofilm performs excellent tolerance to adverse conditions.}, } @article {pmid28370251, year = {2017}, author = {Ząbek, A and Junka, A and Szymczyk, P and Wojtowicz, W and Klimek-Ochab, M and Młynarz, P}, title = {Metabolomics analysis of fungal biofilm development and of arachidonic acid-based quorum sensing mechanism.}, journal = {Journal of basic microbiology}, volume = {57}, number = {5}, pages = {428-439}, doi = {10.1002/jobm.201600636}, pmid = {28370251}, issn = {1521-4028}, mesh = {Arachidonic Acid/*metabolism ; Aspergillus/cytology/genetics/metabolism/pathogenicity ; Biofilms/*growth & development ; Cross Infection ; Fungi/cytology/genetics/*metabolism/pathogenicity ; Genes, Fungal ; Hyphae/cytology/metabolism ; Metabolomics/methods ; Microscopy, Electron, Scanning ; Mycoses/diagnosis ; Plankton/physiology ; Quorum Sensing/*physiology ; }, abstract = {The infections caused by filamentous fungi are becoming worldwide problem of healthcare systems due to increasing drug-resistance of this microorganism and increasing number of immunocompromised nosocomial patients. These infections are related with Aspergillus ability to form sessile communities referred to as the biofilms. The small compounds known as quorum sensing (QS) molecules allow this microorganism to coordinate all processes taking place during biofilm formation and maturation. In the study presented, the HRMAS [1] H NMR metabolomic approach was applied to define composition of extra and intracellular metabolites produced by biofilmic and planktonic (aka free-swimming) cultures of this microorganism and to evaluate impact of quorum sensing molecule, arachidonic acid (AA) on biofilm formation. The Scanning Electron Microscopy was used to confirm Aspergillus ability to form biofilm in vitro, while multivariate and univariate data analysis was applied to analyze data obtained. The Aspergillus strain was able to form strong biofilm structures in vitro. The statistical analysis revealed significant changes of metabolite production depending on Aspergillus culture type (biofilm vs. plankton), time and presence of QS molecules. The data obtained, if developed, might be used in future NMR diagnostics as markers of Aspergillus biofilm-related infections and lead to shorten time between pathogen identification and introduction of treatment.}, } @article {pmid28369412, year = {2017}, author = {Hall, CW and Mah, TF}, title = {Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria.}, journal = {FEMS microbiology reviews}, volume = {41}, number = {3}, pages = {276-301}, doi = {10.1093/femsre/fux010}, pmid = {28369412}, issn = {1574-6976}, support = {//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Drug Resistance, Microbial/*physiology ; Extracellular Matrix/*drug effects ; Microbial Sensitivity Tests ; Plankton/microbiology ; }, abstract = {Biofilms are surface-attached groups of microbial cells encased in an extracellular matrix that are significantly less susceptible to antimicrobial agents than non-adherent, planktonic cells. Biofilm-based infections are, as a result, extremely difficult to cure. A wide range of molecular mechanisms contribute to the high degree of recalcitrance that is characteristic of biofilm communities. These mechanisms include, among others, interaction of antimicrobials with biofilm matrix components, reduced growth rates and the various actions of specific genetic determinants of antibiotic resistance and tolerance. Alone, each of these mechanisms only partially accounts for the increased antimicrobial recalcitrance observed in biofilms. Acting in concert, however, these defences help to ensure the survival of biofilm cells in the face of even the most aggressive antimicrobial treatment regimens. This review summarises both historical and recent scientific data in support of the known biofilm resistance and tolerance mechanisms. Additionally, suggestions for future work in the field are provided.}, } @article {pmid28369127, year = {2017}, author = {Capoor, MN and Ruzicka, F and Schmitz, JE and James, GA and Machackova, T and Jancalek, R and Smrcka, M and Lipina, R and Ahmed, FS and Alamin, TF and Anand, N and Baird, JC and Bhatia, N and Demir-Deviren, S and Eastlack, RK and Fisher, S and Garfin, SR and Gogia, JS and Gokaslan, ZL and Kuo, CC and Lee, YP and Mavrommatis, K and Michu, E and Noskova, H and Raz, A and Sana, J and Shamie, AN and Stewart, PS and Stonemetz, JL and Wang, JC and Witham, TF and Coscia, MF and Birkenmaier, C and Fischetti, VA and Slaby, O}, title = {Propionibacterium acnes biofilm is present in intervertebral discs of patients undergoing microdiscectomy.}, journal = {PloS one}, volume = {12}, number = {4}, pages = {e0174518}, pmid = {28369127}, issn = {1932-6203}, support = {UL1 TR001414/TR/NCATS NIH HHS/United States ; }, mesh = {Adult ; Aged ; Aged, 80 and over ; Biofilms/*growth & development ; Diskectomy ; Female ; Gram-Positive Bacterial Infections/complications/microbiology ; Humans ; Intervertebral Disc/*microbiology/surgery ; Intervertebral Disc Degeneration/etiology/microbiology ; Intervertebral Disc Displacement/etiology/*microbiology/surgery ; Male ; Middle Aged ; Phenotype ; Propionibacterium acnes/*isolation & purification/pathogenicity/*physiology ; Young Adult ; }, abstract = {BACKGROUND: In previous studies, Propionibacterium acnes was cultured from intervertebral disc tissue of ~25% of patients undergoing microdiscectomy, suggesting a possible link between chronic bacterial infection and disc degeneration. However, given the prominence of P. acnes as a skin commensal, such analyses often struggled to exclude the alternate possibility that these organisms represent perioperative microbiologic contamination. This investigation seeks to validate P. acnes prevalence in resected disc cultures, while providing microscopic evidence of P. acnes biofilm in the intervertebral discs.

METHODS: Specimens from 368 patients undergoing microdiscectomy for disc herniation were divided into several fragments, one being homogenized, subjected to quantitative anaerobic culture, and assessed for bacterial growth, and a second fragment frozen for additional analyses. Colonies were identified by MALDI-TOF mass spectrometry and P. acnes phylotyping was conducted by multiplex PCR. For a sub-set of specimens, bacteria localization within the disc was assessed by microscopy using confocal laser scanning and FISH.

RESULTS: Bacteria were cultured from 162 discs (44%), including 119 cases (32.3%) with P. acnes. In 89 cases, P. acnes was cultured exclusively; in 30 cases, it was isolated in combination with other bacteria (primarily coagulase-negative Staphylococcus spp.) Among positive specimens, the median P. acnes bacterial burden was 350 CFU/g (12 - ~20,000 CFU/g). Thirty-eight P. acnes isolates were subjected to molecular sub-typing, identifying 4 of 6 defined phylogroups: IA1, IB, IC, and II. Eight culture-positive specimens were evaluated by fluorescence microscopy and revealed P. acnes in situ. Notably, these bacteria demonstrated a biofilm distribution within the disc matrix. P. acnes bacteria were more prevalent in males than females (39% vs. 23%, p = 0.0013).

CONCLUSIONS: This study confirms that P. acnes is prevalent in herniated disc tissue. Moreover, it provides the first visual evidence of P. acnes biofilms within such specimens, consistent with infection rather than microbiologic contamination.}, } @article {pmid28367877, year = {2017}, author = {Kurakado, S and Takatori, K and Sugita, T}, title = {Minocycline Inhibits Candida albicans Budded-to-Hyphal-Form Transition and Biofilm Formation.}, journal = {Japanese journal of infectious diseases}, volume = {70}, number = {5}, pages = {490-494}, doi = {10.7883/yoken.JJID.2016.369}, pmid = {28367877}, issn = {1884-2836}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Candida albicans/chemistry/*drug effects/genetics/*physiology ; Fungal Proteins/biosynthesis/genetics ; Gene Expression Profiling ; Hydrophobic and Hydrophilic Interactions ; Membrane Glycoproteins/biosynthesis/genetics ; Minocycline/*pharmacology ; Surface Properties ; beta-Glucans/analysis ; }, abstract = {Candida albicans frequently causes bloodstream infections; its budded-to-hyphalform transition (BHT) and biofilm formation are major contributors to virulence. During an analysis of antibacterial compounds that inhibit C. albicans BHT, we found that the tetracycline derivative minocycline inhibited BHT and subsequent biofilm formation. Minocycline decreased expression of hypha-specific genes HWP1 and ECE1, and adhesion factor gene ALS3 of C. albicans. In addition, minocycline decreased cell surface hydrophobicity and the extracellular β-glucan level in biofilms. Minocycline has been widely used for catheter antibiotic lock therapy to prevent bacterial infection; this compound may also be prophylactically effective against Candida infection.}, } @article {pmid28367029, year = {2017}, author = {De, A and Raj, HJ and Haldar, J and Mukherjee, P and Maiti, PK}, title = {Biofilm colonization in chronic treatment refractory infections presenting with discharging sinuses: A study in a tertiary care hospital of Eastern India.}, journal = {Journal of laboratory physicians}, volume = {9}, number = {2}, pages = {125-131}, pmid = {28367029}, issn = {0974-2727}, abstract = {INTRODUCTION: Treatment refractory chronic recurrent infections mean those chronic infections which recur by same causal agents with similar drug responsiveness after apparent relief following full course of recommended antimicrobial management.

MATERIALS AND METHODS: Fifty different samples were collected from patients with chronic surgical site infections, laparoscopic port site infections, anal fistula, mesh hernioplasty, chronic dacryocystitis, chronic osteomyelitis, and chronic burn wounds. Samples were processed for culture, identification, antibiotic sensitivity testing using standard microbiological techniques. Biofilm (BF) forming capacity for aerobic organisms were tested by tissue culture plate method. Those for anaerobes and atypical mycobacteria were studied by a novel method using atomic force microscopy (AFM). In vivo BF colonization in lacrimal mucosae of chronic dacryocystitis, patients were studied from histopathological sections by Gram staining, H and E, and fluorescent in situ hybridization (FISH).

RESULTS: Out of fifty different samples, sixty-three isolates were obtained in pure culture as follows: Staphylococcus aureus (25.39%), Escherichia coli (14.28%), Klebsiella pneumonia (14.28%), Mycobacterium abscessus (12.69%), Citrobacter spp. (9.52%), Bacteroides fragilis (6.3%), Pseudomonas aeruginosa (4.7%), Proteus spp. (4.7%), Staphylococcus epidermidis (3.1%), Enterobacter spp. (1.5%), Morganella morganii (1.5%), and Peptostreptococcus spp. (1.5%). Among the isolates, 74% were found to be BF producers in the following frequency: P. aeruginosa 100%, S. epidermidis 100%, B. fragilis 100%, Klebsiella spp. 88.88%, S. aureus 81.25%, M. abscessus 75%, Citrobacter spp. 83.33%, Proteus spp. 66.66%, E. coli spp. 33.33%, and Enterobacter spp. 0%.

CONCLUSION: AFM has been proven to be a useful method for detection of in vitro grown BF including those for anaerobes and atypical Mycobacteria. In vivo BF detection becomes possible by FISH. S. aureus was the most common isolate. Among the aerobic isolates, P. aeruginosa and S. epidermidis were found to be the most common BF producers. Atypical mycobacteria were also found to be BF producers. Diagnosis of BF s in chronic infections significantly changes the management strategy as these infections can no longer be dealt simply with antibiotics alone but require mechanical removal of the foci along with antibiotic coverage for complete cure.}, } @article {pmid28366827, year = {2017}, author = {Soto, E and Dennis, MM and Beierschmitt, A and Francis, S and Sithole, F and Halliday-Simmons, I and Palmour, R}, title = {Biofilm formation of hypermucoviscous and non-hypermucoviscous Klebsiella pneumoniae recovered from clinically affected African green monkey (Chlorocebus aethiops sabaeus).}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {198-201}, doi = {10.1016/j.micpath.2017.03.034}, pmid = {28366827}, issn = {1096-1208}, mesh = {Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Chlorocebus aethiops/*microbiology ; Klebsiella Infections/*microbiology/*veterinary ; Klebsiella pneumoniae/*genetics/*growth & development/isolation & purification/pathogenicity ; Lung Abscess/microbiology/pathology ; Monkey Diseases/microbiology ; Neutrophils/microbiology ; Phenotype ; Temperature ; Viscosity ; }, abstract = {In recent years, an emergent Klebsiella pneumoniae hypermucoviscous (HMV) phenotype has been associated with increased invasiveness and pathogenicity in primates. The HMV phenotype is characterized by different capsular serotypes, associated with several genes including the rmpA (regulator of mucoid phenotype) and magA (mucoviscosity-associated) genes. In African green monkeys (AGM) (Chlorocebus aethiops sabaeus) serotypes K1 and K5 have been implicated in fatal multisystemic abscesses. In order to better understand the epizootiology of this pathogen, the capacity of biofilm production of K. pneumoniae isolates presenting the HMV was compared to non-HMV isolates at three different temperatures (25, 30 and 37 °C). The results indicate that HMV and non-HMV isolates display similar capacity to form biofilms at the three different evaluated temperatures. Temperature appears to play a role in the formation of biofilms by K. pneumoniae presenting the HMV phenotype, where larger biofilms were formed at 37 °C than at 25 °C. Knowledge regarding local environmental sources of K. pneumoniae and the possible role of wildlife in the maintenance of this agent in the area is necessary to develop effective recommendations for the prevention and management of this disease in captive AGM populations.}, } @article {pmid28365878, year = {2017}, author = {Vaněrková, M and Mališová, B and Kotásková, I and Holá, V and Růžička, F and Freiberger, T}, title = {Biofilm formation, antibiotic susceptibility and RAPD genotypes in Pseudomonas aeruginosa clinical strains isolated from single centre intensive care unit patients.}, journal = {Folia microbiologica}, volume = {62}, number = {6}, pages = {531-538}, pmid = {28365878}, issn = {1874-9356}, support = {16-31593A//Grant of Ministry of Health, CZ/ ; 201404//Internal grant of the Centre for Cardiovascular Surgery and Transplantation Brno, CZ/ ; }, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Drug Resistance, Bacterial ; Female ; Genotype ; Humans ; Intensive Care Units/statistics & numerical data ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/*isolation & purification/physiology ; Random Amplified Polymorphic DNA Technique ; Young Adult ; }, abstract = {The aim of this study was to analyse genotypes, antimicrobial susceptibility patterns and serotypes in Pseudomonas aeruginosa clinical strains, including the clonal dissemination of particular strains throughout various intensive care units in one medical centre. Using random amplified polymorphic DNA (RAPD-PCR) and P. aeruginosa antisera, 22 different genotypes and 8 serotypes were defined among 103 isolates from 48 patients. No direct association between P. aeruginosa strain genotypes and serotypes was observed. RAPD typing in strains with the same serotype revealed different genotypes and, on the contrary, most strains with a different serotype displayed the same amplification pattern. The resulting banding patterns showed a high degree of genetic heterogeneity among all isolates from the patients examined, suggesting a non-clonal relationship between isolates from these patients. A higher degree of antibiotic resistance and stronger biofilm production in common genotypes compared to rare ones and genetic homogeneity of the most resistant strains indicated the role of antibiotic pressure in acquiring resistant and more virulent strains in our hospital. In conclusion, genetic characterisation of P. aeruginosa strains using RAPD method was shown to be more accurate in epidemiological analyses than phenotyping.}, } @article {pmid28365339, year = {2017}, author = {Li, Z and Chang, Q and Li, S and Gao, M and She, Z and Guo, L and Zhao, Y and Jin, C and Zheng, D and Xu, Q}, title = {Impact of sulfadiazine on performance and microbial community of a sequencing batch biofilm reactor treating synthetic mariculture wastewater.}, journal = {Bioresource technology}, volume = {235}, number = {}, pages = {122-130}, doi = {10.1016/j.biortech.2017.03.113}, pmid = {28365339}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors/microbiology ; Nitrogen/metabolism ; Sulfadiazine ; Waste Disposal, Fluid ; Wastewater/*chemistry ; }, abstract = {The impact of sulfadiazine on the performance, microbial activity and microbial community of a sequencing batch biofilm reactor (SBBR) were evaluated in treating mariculture wastewater due to the application of sulfadiazine as an antibiotic in mariculture. The COD and nitrogen removals kept stable at 0-6mg/L sulfadiazine and were inhibited at 10-35mg/L sulfadiazine. The microbial activities related to organic matter and nitrogen removals reduced with an increase in sulfadiazine concentration. The presence of sulfadiazine could affect the production and chemical composition of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) in the biofilm. High-throughput sequencing demonstrated that sulfadiazine could impact on the microbial richness and diversity of SBBR treating mariculture wastewater. The relative abundances of Nitrosomonas, Nitrospira, Paracoccus, Hyphomicrobium, Rhodanobacter, Thauera and Steroidobacter decreased with an increase in sulfadiazine concentration, indicating that the presence of sulfadiazine decreased the relative abundance of some nitrifying and denitrifying bacteria.}, } @article {pmid28365326, year = {2017}, author = {Lopes, LAA and Dos Santos Rodrigues, JB and Magnani, M and de Souza, EL and de Siqueira-Júnior, JP}, title = {Inhibitory effects of flavonoids on biofilm formation by Staphylococcus aureus that overexpresses efflux protein genes.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {193-197}, doi = {10.1016/j.micpath.2017.03.033}, pmid = {28365326}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Flavonoids/administration & dosage/*antagonists & inhibitors/chemistry ; Gene Expression Regulation, Bacterial/*genetics ; Glycosylation/drug effects ; Hesperidin/administration & dosage/antagonists & inhibitors/chemistry ; Membrane Transport Proteins/genetics ; Microbial Sensitivity Tests ; Multidrug Resistance-Associated Proteins/genetics ; Phloretin/administration & dosage/antagonists & inhibitors/chemistry ; Phlorhizin/administration & dosage/antagonists & inhibitors/chemistry ; Staphylococcus aureus/*drug effects/*genetics ; }, abstract = {This study evaluated the efficacy of glycone (myricitrin, hesperidin and phloridzin) and aglycone flavonoids (myricetin, hesperetin and phloretin) in inhibiting biofilm formation by Staphylococcus aureus RN4220 and S. aureus SA1199B that overexpress the msrA and norA efflux protein genes, respectively. The minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC50 - defined as the lowest concentration that resulted in ≥50% inhibition of biofilm formation) of flavonoids were determined using microdilution in broth procedures. The flavonoids showed MIC >1024 μg/mL against S. aureus RN4220 and S. aureus SA1199B; however, these compounds at lower concentrations (1-256 μg/mL) showed inhibitory effects on biofilm formation by these strains. Aglycone flavonoids showed lower MBIC50 values than their respective glycone forms. The lowest MBIC50 values (1 and 4 μg/mL) were observed against S. aureus RN4220. Myricetin, hesperetin and phloretin exhibited biofilm formation inhibition >70% for S. aureus RN4220, and lower biofilm formation inhibition against S. aureus SA1199B. These results indicate that sub-MICs of the tested flavonoids inhibit biofilm formation by S. aureus strains that overexpress efflux protein genes. These effects are more strongly established by aglycone flavonoids.}, } @article {pmid28364889, year = {2017}, author = {Ho, CS and Ming, Y and Foong, KW and Rosa, V and Thuyen, T and Seneviratne, CJ}, title = {Streptococcus mutans forms xylitol-resistant biofilm on excess adhesive flash in novel ex-vivo orthodontic bracket model.}, journal = {American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics}, volume = {151}, number = {4}, pages = {669-677}, doi = {10.1016/j.ajodo.2016.09.017}, pmid = {28364889}, issn = {1097-6752}, mesh = {*Biofilms/growth & development ; Dental Cements/metabolism ; Humans ; Microscopy, Electron, Scanning ; Orthodontic Brackets/*microbiology ; Resin Cements/metabolism ; Streptococcus mutans/drug effects/*growth & development ; Xylitol/*pharmacology ; }, abstract = {INTRODUCTION: During orthodontic bonding procedures, excess adhesive is invariably left on the tooth surface at the interface between the bracket and the enamel junction; it is called excess adhesive flash (EAF). We comparatively evaluated the biofilm formation of Streptococcus mutans on EAF produced by 2 adhesives and examined the therapeutic efficacy of xylitol on S mutans formed on EAF.

METHODS: First, we investigated the biofilm formation of S mutans on 3 orthodontic bracket types: stainless steel preadjusted edgewise, ceramic preadjusted edgewise, and stainless steel self-ligating. Subsequently, tooth-colored Transbond XT (3M Unitek, Monrovia, Calif) and green Grengloo (Ormco, Glendora, Calif) adhesives were used for bonding ceramic brackets to extracted teeth. S mutans biofilms on EAF produced by the adhesives were studied using the crystal violet assay and scanning electron microscopy. Surface roughness and surface energy of the EAF were examined. The therapeutic efficacies of different concentrations of xylitol were tested on S mutans biofilms.

RESULTS: Significantly higher biofilms were formed on the ceramic preadjusted edgewise brackets (P = 0.003). Transbond XT had significantly higher S mutans biofilms compared with Grengloo surfaces (P = 0.007). There was no significant difference in surface roughness between Transbond XT and Grengloo surfaces (P >0.05). Surface energy of Transbond XT had a considerably smaller contact angle than did Grengloo, suggesting that Transbond XT is a more hydrophilic material. Xylitol at low concentrations had no significant effect on the reduction of S mutans biofilms on orthodontic adhesives (P = 0.016).

CONCLUSIONS: Transbond XT orthodontic adhesive resulted in more S mutans biofilm compared with Grengloo adhesive on ceramic brackets. Surface energy seemed to play a more important role than surface roughness for the formation of S mutans biofilm on EAF. Xylitol does not appear to have a therapeutic effect on mature S mutans biofilm.}, } @article {pmid28364732, year = {2017}, author = {Gomes, LC and Mergulhão, FJ}, title = {Effects of antibiotic concentration and nutrient medium composition on Escherichia coli biofilm formation and green fluorescent protein expression.}, journal = {FEMS microbiology letters}, volume = {364}, number = {5}, pages = {}, doi = {10.1093/femsle/fnx042}, pmid = {28364732}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Culture Media/*chemistry ; Escherichia coli/*drug effects/genetics/physiology ; Green Fluorescent Proteins/biosynthesis/*genetics ; Kanamycin/pharmacology ; Plasmids ; Recombinant Proteins/biosynthesis ; }, abstract = {Recombinant protein production processes have to maximise yield while minimising cost, which involves balancing plasmid maintenance with cell growth and protein expression. The aim of this study was to analyse the influence of two factors on heterologous protein production in Escherichia coli biofilm cells-the concentration of antibiotic used to maintain the selective pressure and the nutrient medium composition. Escherichia coli JM109(DE3) cells transformed with plasmid pFM23 for enhanced green fluorescent protein (eGFP) expression and containing a kanamycin resistance gene were used. They were exposed to 20 or 30 μg mL-1 kanamycin during biofilm growth in two different culture media, a diluted medium (DM) or the lysogeny broth (LB). The higher antibiotic concentration increased the specific eGFP production in planktonic cells, whereas no increase was detected in biofilm cells. Biofilm formation was increased in DM when compared to LB. Nevertheless, bacteria grown in LB had higher eGFP production than those grown in DM in both planktonic and sessile states (20-fold and 2-fold, respectively). Therefore, among the conditions tested, LB supplemented with 20 μg mL-1 kanamycin was the most advantageous medium to obtain the highest specific eGFP production in biofilm cells.}, } @article {pmid28363757, year = {2017}, author = {Kim, CH and Lee, ES and Kang, SM and de Josselin de Jong, E and Kim, BI}, title = {Bactericidal effect of the photocatalystic reaction of titanium dioxide using visible wavelengths on Streptococcus mutans biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {18}, number = {}, pages = {279-283}, doi = {10.1016/j.pdpdt.2017.03.015}, pmid = {28363757}, issn = {1873-1597}, mesh = {Anti-Bacterial Agents/administration & dosage ; Biofilms/*drug effects/*growth & development/radiation effects ; Catalysis/drug effects/radiation effects ; Disinfection/*methods ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage ; Streptococcus mutans/cytology/*drug effects/*radiation effects ; Titanium/*administration & dosage ; Treatment Outcome ; }, abstract = {BACKGROUND: The aim of this study was to determine the effect of titanium dioxide (TiO2) photocatalysis induced by the application of clinically acceptable visible light at 405nm on the growth of Streptococcus mutans biofilms.

METHODS: S. mutans biofilms were grown on a hydroxyapatite (HA) disk and deposited in a rutile-type TiO2 solution at a concentration of 0.1mg/mL. TiO2 photocatalysis was measured for exposure to visible light (405nm) and ultraviolet (UV) light (254nm) produced by light-emitting diodes for 10, 20, 30, and 40min. After two treatments, the number of colonies formed in the final S. mutans biofilm on the HA disk were measured to confirm their viability, and the morphological changes of S. mutans were evaluated using scanning electronic microscopy.

RESULTS: The bactericidal effects of 254- and 405-nm light resulted in > 5-log and 4-log reductions, respectively (p<0.05), after 20min of treatment and a>7-log reduction after 40min of treatment in both treatment groups relative to the control group.

CONCLUSION: It was confirmed that the antibacterial effect could be shown by causing the photocatalytic reaction of TiO2 in S. mutans biofilm even at the wavelength of visible light (405nm) as at the wavelength of ultraviolet light (254nm).}, } @article {pmid28362216, year = {2018}, author = {Roy, R and Tiwari, M and Donelli, G and Tiwari, V}, title = {Strategies for combating bacterial biofilms: A focus on anti-biofilm agents and their mechanisms of action.}, journal = {Virulence}, volume = {9}, number = {1}, pages = {522-554}, pmid = {28362216}, issn = {2150-5608}, mesh = {Anti-Bacterial Agents/*isolation & purification/*pharmacology ; Bacteria/*drug effects/*growth & development ; Biofilms/*drug effects/*growth & development ; Drug Discovery/methods/*trends ; Inhibitory Concentration 50 ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby investigating its effective delivery in the host. It should also be ensured that minimum effective concentration of these molecules must be capable of eradicating biofilm infections with maximum potency without posing any adverse side effects on the host.}, } @article {pmid28362105, year = {2017}, author = {Favre, L and Ortalo-Magné, A and Greff, S and Pérez, T and Thomas, OP and Martin, JC and Culioli, G}, title = {Discrimination of Four Marine Biofilm-Forming Bacteria by LC-MS Metabolomics and Influence of Culture Parameters.}, journal = {Journal of proteome research}, volume = {16}, number = {5}, pages = {1962-1975}, doi = {10.1021/acs.jproteome.6b01027}, pmid = {28362105}, issn = {1535-3907}, mesh = {Bacteria/*cytology/growth & development/metabolism ; Bacterial Typing Techniques/*methods ; Biofilms ; Biomarkers/analysis ; Chromatography, Liquid ; Marine Biology ; Metabolomics/*methods ; Tandem Mass Spectrometry ; }, abstract = {Most marine bacteria can form biofilms, and they are the main components of biofilms observed on marine surfaces. Biofilms constitute a widespread life strategy, as growing in such structures offers many important biological benefits. The molecular compounds expressed in biofilms and, more generally, the metabolomes of marine bacteria remain poorly studied. In this context, a nontargeted LC-MS metabolomics approach of marine biofilm-forming bacterial strains was developed. Four marine bacteria, Persicivirga (Nonlabens) mediterranea TC4 and TC7, Pseudoalteromonas lipolytica TC8, and Shewanella sp. TC11, were used as model organisms. The main objective was to search for some strain-specific bacterial metabolites and to determine how culture parameters (culture medium, growth phase, and mode of culture) may affect the cellular metabolism of each strain and thus the global interstrain metabolic discrimination. LC-MS profiling and statistical partial least-squares discriminant analyses showed that the four strains could be differentiated at the species level whatever the medium, the growth phase, or the mode of culture (planktonic vs biofilm). A MS/MS molecular network was subsequently built and allowed the identification of putative bacterial biomarkers. TC8 was discriminated by a series of ornithine lipids, while the P. mediterranea strains produced hydroxylated ornithine and glycine lipids. Among the P. mediterranea strains, TC7 extracts were distinguished by the occurrence of diamine derivatives, such as putrescine amides.}, } @article {pmid28361145, year = {2017}, author = {Gu, J and Valdevit, A and Chou, TM and Libera, M}, title = {Substrate effects on cell-envelope deformation during early-stage Staphylococcus aureus biofilm formation.}, journal = {Soft matter}, volume = {13}, number = {16}, pages = {2967-2976}, doi = {10.1039/c6sm02815b}, pmid = {28361145}, issn = {1744-6848}, mesh = {Alkanes/chemistry ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/*growth & development ; Cell Shape/drug effects ; Gold/chemistry ; Polyethylene Glycols/chemistry ; Polystyrenes/chemistry/pharmacology ; Staphylococcus aureus/cytology/*drug effects/*physiology ; Sulfhydryl Compounds/chemistry ; Surface Properties ; Time Factors ; }, abstract = {Bacterial adhesion to a surface is the first step in biofilm formation, and adhesive forces between the surface and a bacterium are believed to give rise to planktonic-to-biofilm phenotypic changes. Here we use Focused-Ion-Beam (FIB) tomography with backscattered scanning electron microscopy (SEM) to image Staphyolococcus aureus (S. aureus) biofilms grown on Au-coated polystyrene (PS) and Au-coated PS modified by mixed thiols of triethylene glycol mono-11-mercaptoundecyl ether (EG3) and 1-dodecanethiol (CH3). The FIB-SEM technique enables a direct measurement of the contact area between individual bacteria and the substrate. The area of adhesion is effectively zero on the EG3 substrate. It is nonzero on all of the other substrates and increases with increasing hydrophobicity. The fact that the contact area is highest on the unmodified gold, however, indicates that other forces beyond hydrophobicity are significant. The magnitude of bacterial deformation suggests that the adhesive forces are on the order of a few nN, consistent with AFM force measurements reported in the literature. The resolution afforded by electron microscopy furthermore enables us to probe changes in the cell-envelope thickness, which decreases within and near the contact area relative to other parts of the same bacterium. This finding supports the idea that mechanosensing due to stress-induced membrane thinning plays a role in the planktonic-to-biofilm transition associated with bacterial adhesion.}, } @article {pmid28361040, year = {2017}, author = {Levipan, HA and Avendaño-Herrera, R}, title = {Different Phenotypes of Mature Biofilm in Flavobacterium psychrophilum Share a Potential for Virulence That Differs from Planktonic State.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {76}, pmid = {28361040}, issn = {2235-2988}, mesh = {Biofilms/*growth & development ; Flavobacterium/genetics/growth & development/*physiology ; Gene Expression Profiling ; Phenotype ; Virulence ; }, abstract = {Flavobacterium psychrophilum is the etiological agent of bacterial coldwater disease and the rainbow trout fry syndrome in salmonid aquaculture worldwide. However, there have been few studies into the capacity of F. psychrophilum to form biofilms and how these cellular accretions differ from planktonic cells or how they affect potential virulence. We evaluated the biofilm formation by three Chilean isolates of F. psychrophilum (LM-02-Fp, LM-06-Fp, and LM-13-Fp) and two non-Chilean strains (JIP02/86 and NCMB1947[T]), and compared biofilm and planktonic states to obtain insights into expression differences of virulence- and biofilm-related genes (VBRGs). Our findings are based on scanning confocal laser microscopy (SCLM) and LIVE/DEAD staining, enzymatic reactions, reverse transcription-quantitative PCR (RT-qPCR) of genes encoding putative virulence factors, and transcriptomes (RNA-Seq). The LM-02-Fp and NCMB1947[T] strains were the strongest and weakest biofilm producers, respectively. The strong-biofilm producer showed different physiological cell states distributed in different layers of mature biofilms, whereas the NCMB1947[T] biofilms consisted of cells arranged in a monolayer. WGA-binding exopolysaccharides would be the main components of their corresponding extracellular matrices. Transcriptomes of F. psychrophilum NCMB1947[T] and LM-02-Fp were clustered by state (biofilm vs. planktonic) rather than by strain, indicating important state-dependent differences in gene expression. Analysis of differentially expressed genes between states identified putative VBRGs involved in polysaccharide biosynthesis, lateral gene transfer, membrane transport (e.g., for drugs and Fe[3+]), sensory mechanisms, and adhesion, and indicated that about 60-100% of VBRGs involved in these processes was significantly upregulated in the biofilm state. Conversely, upregulated motility-related genes in the biofilm state were not identified, whereas a lower fraction of proteolysis-related genes (33%) was upregulated in biofilms. In summary, F. psychrophilum strains that produce different biofilm phenotypes show global transcriptional activity in the mature biofilm state that differs significantly from their planktonic counterparts. Also, different biofilm phenotypes share a genetic potential for virulence that is transcriptionally enhanced with respect to free-living cells. Our results suggest that the F. psychrophilum biofilm lifestyle acts as a reservoir for a given set of putative virulence factors, and recommend a deeper understanding of which could help prevent recurring infections in salmonid farms.}, } @article {pmid28360007, year = {2017}, author = {Fish, K and Osborn, AM and Boxall, JB}, title = {Biofilm structures (EPS and bacterial communities) in drinking water distribution systems are conditioned by hydraulics and influence discolouration.}, journal = {The Science of the total environment}, volume = {593-594}, number = {}, pages = {571-580}, doi = {10.1016/j.scitotenv.2017.03.176}, pmid = {28360007}, issn = {1879-1026}, mesh = {Bacteria/*growth & development ; *Biofilms ; Drinking Water/*microbiology ; *Water Quality ; *Water Supply ; }, abstract = {High-quality drinking water from treatment works is degraded during transport to customer taps through the Drinking Water Distribution System (DWDS). Interactions occurring at the pipe wall-water interface are central to this degradation and are often dominated by complex microbial biofilms that are not well understood. This study uses novel application of confocal microscopy techniques to quantify the composition of extracellular polymeric substances (EPS) and cells of DWDS biofilms together with concurrent evaluation of the bacterial community. An internationally unique, full-scale, experimental DWDS facility was used to investigate the impact of three different hydraulic patterns upon biofilms and subsequently assess their response to increases in shear stress, linking biofilms to water quality impacts such as discolouration. Greater flow variation during growth was associated with increased cell quantity but was inversely related to EPS-to-cell volume ratios and bacterial diversity. Discolouration was caused and EPS was mobilised during flushing of all conditions. Ultimately, biofilms developed under low-varied flow conditions had lowest amounts of biomass, the greatest EPS volumes per cell and the lowest discolouration response. This research shows that the interactions between hydraulics and biofilm physical and community structures are complex but critical to managing biofilms within ageing DWDS infrastructure to limit water quality degradation and protect public health.}, } @article {pmid28358851, year = {2017}, author = {Zhang, QZ and Zhao, KQ and Wu, Y and Li, XH and Yang, C and Guo, LM and Liu, CH and Qu, D and Zheng, CQ}, title = {5-aminolevulinic acid-mediated photodynamic therapy and its strain-dependent combined effect with antibiotics on Staphylococcus aureus biofilm.}, journal = {PloS one}, volume = {12}, number = {3}, pages = {e0174627}, pmid = {28358851}, issn = {1932-6203}, mesh = {Aminolevulinic Acid/administration & dosage ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/radiation effects ; Humans ; Microbial Sensitivity Tests ; Photochemotherapy ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects/pathogenicity ; }, abstract = {Staphylococcus aureus (S. aureus) is hard to be eradicated, not only due to the emergence of antibiotic resistant strains but also because of its ability to form biofilm. Antibiotics are the major approach to treating biofilm infections, but their effects are unsatisfactory. One of the potential alternative treatments for controlling biofilm infections is photodynamic therapy (PDT), which requires the administration of photosensitizer, followed by light activation. 5-aminolevulinic acid (ALA), a natural photosensitizer prodrug, presents favorable characteristics, such as easy penetration and rapid clearance. These advantages enable ALA-based PDT (ALA-PDT) to be well-tolerated by patients and it can be repeatedly applied without cumulative toxicity or serious side effects. ALA-PDT has been proven to be an effective treatment for multidrug resistant pathogens; however, the study of its effect on S. aureus biofilm is limited. Here, we established our PDT system based on the utilization of ALA and a light-emitting diode, and we tested the effect of ALA-PDT on S. aureus biofilm as well as the combined effect of ALA-PDT and antibiotics on S. aureus biofilm. Our results showed that ALA-PDT has a strong antibacterial effect on S. aureus biofilm, which was confirmed by the confocal laser scanning microscope. We also found that lethal photosensitization occurred predominantly in the upper layer of the biofilm, while the residual live bacteria were located in the lower layer of the biofilm. In addition, the improved bactericidal effect was observed in the combined treatment group but in a strain-dependent manner. Our results suggest that ALA-PDT is a potential alternative approach for future clinical use to treat S. aureus biofilm-associated infections, and some patients may benefit from the combined treatment of ALA-PDT and antibiotics, but drug sensitivity testing should be performed in advance.}, } @article {pmid28358585, year = {2017}, author = {Jung, HS and Ehlers, MM and Lombaard, H and Redelinghuys, MJ and Kock, MM}, title = {Etiology of bacterial vaginosis and polymicrobial biofilm formation.}, journal = {Critical reviews in microbiology}, volume = {43}, number = {6}, pages = {651-667}, doi = {10.1080/1040841X.2017.1291579}, pmid = {28358585}, issn = {1549-7828}, mesh = {Bacteria, Anaerobic/*growth & development/*pathogenicity ; Bacterial Adhesion ; Biofilms/*growth & development ; Female ; Humans ; Microbiota/physiology ; Vagina/*microbiology ; Vaginosis, Bacterial/*microbiology ; }, abstract = {Microorganisms in nature rarely exist in a planktonic form, but in the form of biofilms. Biofilms have been identified as the cause of many chronic and persistent infections and have been implicated in the etiology of bacterial vaginosis (BV). Bacterial vaginosis is the most common form of vaginal infection in women of reproductive age. Similar to other biofilm infections, BV biofilms protect the BV-related bacteria against antibiotics and cause recurrent BV. In this review, an overview of BV-related bacteria, conceptual models and the stages involved in the polymicrobial BV biofilm formation will be discussed.}, } @article {pmid28358306, year = {2017}, author = {Jiang, S and Chen, S and Zhang, C and Zhao, X and Huang, X and Cai, Z}, title = {Effect of the Biofilm Age and Starvation on Acid Tolerance of Biofilm Formed by Streptococcus mutans Isolated from Caries-Active and Caries-Free Adults.}, journal = {International journal of molecular sciences}, volume = {18}, number = {4}, pages = {}, pmid = {28358306}, issn = {1422-0067}, mesh = {Acids/*pharmacology ; Adaptation, Physiological ; Adult ; Biofilms/*drug effects/growth & development ; Humans ; Hydrogen-Ion Concentration ; Streptococcus mutans/isolation & purification/metabolism/*physiology ; }, abstract = {Streptococcus mutans (S. mutans) is considered a leading cause of dental caries. The capability of S. mutans to tolerate low pH is essential for its cariogenicity. Aciduricity of S. mutans is linked to its adaptation to environmental stress in oral cavity. This study aimed to investigate the effect of biofilm age and starvation condition on acid tolerance of biofilm formed by S. mutans clinical isolates. S. mutans clinical strains isolated from caries-active (SM593) and caries-free (SM18) adults and a reference strain (ATCC25175) were used for biofilm formation. (1) Both young and mature biofilms were formed and then exposed to pH 3.0 for 30 min with (acid-adapted group) or without (non-adapted group) pre-exposure to pH 5.5 for three hours. (2) The mature biofilms were cultured with phosphate-buffered saline (PBS) (starved group) or TPY (polypeptone-yeast extract) medium (non-starved group) at pH 7.0 for 24 h and then immersed in medium of pH 3.0 for 30 min. Biofilms were analyzed through viability staining and confocal laser scanning microscopy. In all three strains, mature, acid-adapted and starved biofilms showed significantly less destructive structure and more viable bacteria after acid shock than young, non-adapted and non-starved biofilms, respectively (all p < 0.05). Furthermore, in each condition, SM593 biofilm was denser, with a significantly larger number of viable bacteria than that of SM18 and ATCC25175 (all p < 0.05). Findings demonstrated that mature, acid-adapted and starvation might protect biofilms of all three S. mutans strains against acid shock. Additionally, SM593 exhibited greater aciduricity compared to SM18 and ATCC25175, which indicated that the colonization of high cariogenicity of clinical strains may lead to high caries risk in individuals.}, } @article {pmid28358260, year = {2017}, author = {Girbau, C and Martinez-Malaxetxebarria, I and Muruaga, G and Carmona, S and Alonso, R and Fernandez-Astorga, A}, title = {Study of Biofilm Formation Ability of Foodborne Arcobacter butzleri under Different Conditions.}, journal = {Journal of food protection}, volume = {80}, number = {5}, pages = {758-762}, doi = {10.4315/0362-028X.JFP-16-505}, pmid = {28358260}, issn = {1944-9097}, abstract = {The transmission of Arcobacter butzleri, an emerging food- and waterborne pathogen, is possibly favored by its ability to adhere to abiotic surfaces. In this study, we assessed the biofilm formation ability of 42 A. butzleri isolates recovered from different food products. Overall, nine isolates (21.4%) were able to adhere to polystyrene. Among them, a chicken-derived isolate was classified as strongly adherent. Based on the chi-square test, no relation was found between the adhesive abilities of the isolates and their source (P > 0.05). An aerobic atmosphere enhanced the adhesion ability of the majority of the adherent isolates (66.7%), because when tested in microaerobic conditions, a t test indicated that only three isolates increased their biofilm formation ability significantly (P < 0.05). In addition, seven (77.8%) of these nine isolates were able to adhere to glass surfaces, and viable cells were recovered from all the stainless steel coupons tested. Therefore, our results confirm the biofilm formation ability of A. butzleri, which may be influenced by the incubation atmosphere and the abiotic surface.}, } @article {pmid28357473, year = {2017}, author = {Anand, R and Clemons, KV and Stevens, DA}, title = {Effect of Anaerobiasis or Hypoxia on Pseudomonas aeruginosa Inhibition of Aspergillus fumigatus Biofilm.}, journal = {Archives of microbiology}, volume = {199}, number = {6}, pages = {881-890}, doi = {10.1007/s00203-017-1362-5}, pmid = {28357473}, issn = {1432-072X}, mesh = {Anaerobiosis ; Aspergillus fumigatus/*physiology ; *Biofilms ; Humans ; Microbial Interactions ; Oxygen/analysis/*metabolism ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) are the major bacterial and fungal pathogens in the airways of cystic fibrosis (CF) patients. This is likely related to their ability to form biofilms. Both microbes have been associated with CF disease progression. The interplay between these two pathogens has been studied under aerobic conditions, though accumulating data indicates that much of the CF airway is hypoxic or anaerobic. We studied the microbial interaction in these latter environments. Pa is an aggressor against Af forming biofilm or as established Af biofilm, whether Pa is cultivated in aerobic, hypoxic, or anaerobic conditions, or tested in aerobic or hypoxic conditions. Pa cells are generally more effective than planktonic or biofilm culture filtrates. Pa growth is less in anaerobic conditions, and filtrates less effective after anaerobic or hypoxic growth, or against hypoxic Af. These, and other comparisons shown, indicate that Pa would be less effective in such environments, as would be the case in a CF mucus plug. These observations would explain why Pa becomes established in CF airways before Af, and why Af may persist during disease progression.}, } @article {pmid28355248, year = {2017}, author = {Jorge, P and Grzywacz, D and Kamysz, W and Lourenço, A and Pereira, MO}, title = {Searching for new strategies against biofilm infections: Colistin-AMP combinations against Pseudomonas aeruginosa and Staphylococcus aureus single- and double-species biofilms.}, journal = {PloS one}, volume = {12}, number = {3}, pages = {e0174654}, pmid = {28355248}, issn = {1932-6203}, mesh = {3T3 Cells ; Algorithms ; Amphibian Proteins/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Colistin/*pharmacology ; DNA-Binding Proteins/pharmacology ; Drug Synergism ; Fibroblasts/cytology/drug effects ; Mice ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Fluorescence ; Peptides, Cyclic/pharmacology ; Plankton/microbiology ; Proteins/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Antimicrobial research is being pressured to look for more effective therapeutics for the ever-growing antibiotic-resistant infections, and antimicrobial peptides (AMP) and antimicrobial combinations are promising solutions. This work evaluates colistin-AMP combinations against two major pathogens, Pseudomonas aeruginosa and Staphylococcus aureus, encompassing non- and resistant strains. Colistin (CST) combined with the AMP temporin A (TEMP-A), citropin 1.1 (CIT-1.1) and tachyplesin I linear analogue (TP-I-L) was tested against planktonic, single- and double-species biofilm cultures. Overall synergy for planktonic P. aeruginosa and synergy/additiveness for planktonic S. aureus were observed. Biofilm growth prevention was achieved with synergy and additiveness. Pre-established 24 h-old biofilms were harder to eradicate, especially for S. aureus and double-species biofilms; still, some synergy and addictiveness was observed for higher concentrations, including for the biofilms of resistant strains. Different treatment times and growth media did not greatly influence AMP activity. CST revealed low toxicity compared with the other AMP but its combinations were toxic for high concentrations. Overall, combinations reduced effective AMP concentrations, mainly in prevention scenarios. Improvement of effectiveness and toxicity of therapeutic strategies will be further investigated.}, } @article {pmid28352865, year = {2017}, author = {Pouran, HM and Banwart, SA and Romero-Gonzalez, M}, title = {Effects of synthetic iron and aluminium oxide surface charge and hydrophobicity on the formation of bacterial biofilm.}, journal = {Environmental science. Processes & impacts}, volume = {19}, number = {4}, pages = {622-634}, doi = {10.1039/c6em00666c}, pmid = {28352865}, issn = {2050-7895}, mesh = {Aluminum Oxide/*chemistry ; *Bacterial Adhesion ; Biofilms/*growth & development ; *Cell Adhesion ; England ; *Hydrophobic and Hydrophilic Interactions ; Iron/*chemistry ; Pseudomonas/growth & development ; Rhodococcus/growth & development ; Sphingomonas/growth & development ; }, abstract = {In this research, bacterial cell attachments to hematite, goethite and aluminium hydroxide were investigated. The aim was to study the effects of these minerals' hydrophobicity and pH-dependent surface charge on the extent of biofilm formation using six genetically diverse bacterial strains: Rhodococcus spp. (RC92 & RC291), Pseudomonas spp. (Pse1 & Pse2) and Sphingomonas spp. (Sph1 & Sph2), which had been previously isolated from contaminated environments. The surfaces were prepared in a way that was compatible with the naturally occurring coating process in aquifers: deposition of colloidal particles from the aqueous phase. The biofilms were evaluated using a novel, in situ and non-invasive technique developed for this purpose. A manufactured polystyrene 12-well plate was used as the reference surface to be coated with synthesized minerals by deposition of their suspended particles through evaporation. Planktonic phase growth indicates that it is independent of the surface charge and hydrophobicity of the studied surfaces. The hydrophobic similarities failed to predict biofilm proliferation. Two of the three hydrophilic strains formed extensive biofilms on the minerals. The third one, Sph2, showed anomalies in contrast to the expected electrostatic attraction between the minerals and the cell surface. Further research showed how the solution's ionic strength affects Sph2 surface potential and shapes the extent of its biofilm formation; reducing the ionic strength from ≈200 mM to ≈20 mM led to a tenfold increase in the number of cells attached to hematite. This study provides a technique to evaluate biofilm formation on metal-oxide surfaces, under well-controlled conditions, using a simple yet reliable method. The findings also highlight that cell numbers in the planktonic phase do not necessarily show the extent of cell attachment, and thorough physicochemical characterization of bacterial strains, substrata and the aquifer medium is fundamental to successfully implementing any bioremediation projects.}, } @article {pmid28351714, year = {2017}, author = {Moliva, MV and Cerioli, F and Reinoso, EB}, title = {Evaluation of environmental and nutritional factors and sua gene on in vitro biofilm formation of Streptococcus uberis isolates.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {144-148}, doi = {10.1016/j.micpath.2017.03.028}, pmid = {28351714}, issn = {1096-1208}, mesh = {Animals ; Argentina ; Bacterial Adhesion/*drug effects/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/*growth & development ; Caseins/pharmacology ; Cattle ; Culture Media/chemistry ; DNA, Bacterial/genetics ; Deoxyribonuclease I/pharmacology ; Female ; Genes, Bacterial/genetics ; Glucose/pharmacology ; Hydrogen-Ion Concentration ; Lactose/pharmacology ; Mastitis/microbiology ; Mastitis, Bovine/microbiology ; Milk/chemistry/microbiology ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S/genetics ; Serum Albumin, Bovine/pharmacology ; Streptococcal Infections/microbiology ; Streptococcus/drug effects/*genetics/isolation & purification/pathogenicity ; Temperature ; }, abstract = {The pathogenesis of Streptococcus uberis is attributed to a combination of extracellular factors and properties such as adherence and biofilm formation. The aim of this work was to evaluate the influence of different factors, additives and bovine milk compounds on S. uberis biofilm formation, as the presence of the sua gene by PCR. Additionally, extracellular DNA and the effect of DNaseI were evaluated in the biofilms yielded. Optimal biofilm development was observed when the pH was adjusted to 7.0 and 37 °C. Additives as glucose and lactose reduced biofilm formation as bovine milk compounds tested. PCR assay showed that not all the isolates yielded sua gene. Extrachromosomal ADN was found in cell-free supernatants, suggesting that DNA released spontaneously to the medium. The results contribute to a better understanding of the factors involved in biofilm production of this important pathogen associated with mastitis in order to promote the design of new therapeutic approaches.}, } @article {pmid28351512, year = {2017}, author = {Hogan, S and Zapotoczna, M and Stevens, NT and Humphreys, H and O'Gara, JP and O'Neill, E}, title = {Potential use of targeted enzymatic agents in the treatment of Staphylococcus aureus biofilm-related infections.}, journal = {The Journal of hospital infection}, volume = {96}, number = {2}, pages = {177-182}, doi = {10.1016/j.jhin.2017.02.008}, pmid = {28351512}, issn = {1532-2939}, mesh = {Adult ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Synergism ; Enzymes/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/*drug effects ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Staphylococcus aureus is a leading cause of healthcare-associated infections. The ability of S. aureus to attach and subsequently accumulate on the surfaces of implanted medical devices and in host tissues makes infections caused by this pathogen difficult to treat. Current treatments have been shown to have limited effect on surface-associated S. aureus, and may be enhanced by the addition of a dispersal agent. This study assessed the enzymatic agents dispersin B, lysostaphin, alpha amylase, V8 protease and serrapeptase, alone and in combination with vancomycin and rifampicin, against biofilms formed by meticillin-resistant and -susceptible strains of S. aureus. The efficacy of both antibiotics was enhanced when combined with any of the dispersal agents. Lysostaphin and serrapeptase were the most effective dispersal agents against all strains tested. These data indicate that combinations of biofilm dispersal agents and antibiotics may extend the therapeutic options for the treatment of S. aureus biofilm-associated infections.}, } @article {pmid28350350, year = {2017}, author = {Moreno-García, J and Mauricio, JC and Moreno, J and García-Martínez, T}, title = {Differential Proteome Analysis of a Flor Yeast Strain under Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {18}, number = {4}, pages = {}, pmid = {28350350}, issn = {1422-0067}, mesh = {Biofilms ; Gene Expression Regulation, Fungal ; Gene Ontology ; Metabolic Networks and Pathways ; Proteomics/*methods ; Saccharomyces cerevisiae/metabolism/*physiology ; Saccharomyces cerevisiae Proteins/*metabolism ; }, abstract = {Several Saccharomyces cerevisiae strains (flor yeasts) form a biofilm (flor velum) on the surface of Sherry wines after fermentation, when glucose is depleted. This flor velum is fundamental to biological aging of these particular wines. In this study, we identify abundant proteins in the formation of the biofilm of an industrial flor yeast strain. A database search to enrich flor yeast "biological process" and "cellular component" according to Gene Ontology Terminology (GO Terms) and, "pathways" was carried out. The most abundant proteins detected were largely involved in respiration, translation, stress damage prevention and repair, amino acid metabolism (glycine, isoleucine, leucine and arginine), glycolysis/gluconeogenesis and biosynthesis of vitamin B9 (folate). These proteins were located in cellular components as in the peroxisome, mitochondria, vacuole, cell wall and extracellular region; being these two last directly related with the flor formation. Proteins like Bgl2p, Gcv3p, Hyp2p, Mdh1p, Suc2p and Ygp1p were quantified in very high levels. This study reveals some expected processes and provides new and important information for the design of conditions and genetic constructions of flor yeasts for improving the cellular survival and, thus, to optimize biological aging of Sherry wine production.}, } @article {pmid28349902, year = {2017}, author = {Chaves, RM and Estrela, C and Cardoso, PC and de Je Barata, T and de Souza, JB and de Torres, ÉM and Estrela, CR and Magalhães, AP and Lopes, LG}, title = {Ozone Gas Effect on Mineral Content of Dentin exposed to Streptococcus mutans Biofilm: An Energy-dispersive X-ray Evaluation.}, journal = {The journal of contemporary dental practice}, volume = {18}, number = {4}, pages = {265-269}, doi = {10.5005/jp-journals-10024-2029}, pmid = {28349902}, issn = {1526-3711}, mesh = {Biofilms/*drug effects ; Calcium/*analysis ; Dentin/chemistry/*drug effects/microbiology ; Humans ; Ozone/*adverse effects ; Phosphorus/*analysis ; Spectrometry, X-Ray Emission ; Streptococcus mutans/*drug effects ; }, abstract = {AIM: This study aims to assess the effect of ozone gas on dentin exposed to Streptococcus mutans biofilm by evaluation of mineral content [log calcium-to-phosphorus (Ca/P)] using energy-dispersive X-ray (EDX) spectroscopy.

MATERIALS AND METHODS: Five human third molars were sectioned into four slices of dentin and distributed in four groups: I - control (no treatment); II - ozone therapy; III - biofilm development; IV - ozone therapy followed by biofilm development. Mineral content (log Ca/P) was evaluated by EDX. Data were analyzed by analysis of variance and Tukey's test (p < 0.05).

RESULTS: Results showed that the mineral content of control group (I) was similar to ozone group (II), and was statistically higher than biofilm (III) and ozone + biofilm (IV). The lowest log Ca/P was determined in biofilm group (III).

CONCLUSION: It can be concluded that ozone gas did not grant preventive effects of demineralization by S. mutans biofilm on dentin surface.

CLINICAL SIGNIFICANCE: Ozone gas therapy may be an alternative noninvasive treatment aiming to reduce the levels of caries-associated microorganisms. This therapy may, thereby, be an alternative and/or complementary treatment strategy in preventive dentistry.}, } @article {pmid28348056, year = {2017}, author = {Nickerson, KP and Chanin, RB and Sistrunk, JR and Rasko, DA and Fink, PJ and Barry, EM and Nataro, JP and Faherty, CS}, title = {Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts.}, journal = {Infection and immunity}, volume = {85}, number = {6}, pages = {}, pmid = {28348056}, issn = {1098-5522}, support = {K22 AI104755/AI/NIAID NIH HHS/United States ; R25 DK103579/DK/NIDDK NIH HHS/United States ; T32 AI095190/AI/NIAID NIH HHS/United States ; U19 AI110820/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Bile Acids and Salts/*pharmacology ; Biofilms/*drug effects ; Gene Expression Profiling ; HT29 Cells ; HeLa Cells ; Humans ; Microscopy, Electron ; Mutation ; O Antigens/genetics/*metabolism ; Sequence Analysis, RNA ; Shigella flexneri/*drug effects/genetics/*pathogenicity ; Virulence/genetics ; }, abstract = {The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge regarding how the bacteria survive, transit, and regulate gene expression prior to infection remain. In this study, we define mechanisms of resistance to bile salts and build on previous research highlighting induced virulence in Shigella flexneri strain 2457T following exposure to bile salts. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations. Interestingly, extended periods of exposure to bile salts led to biofilm formation, a conserved phenotype that we observed among members of the Enterobacteriaceae Characterization of S. flexneri 2457T biofilms determined that both bile salts and glucose were required for formation, dispersion was dependent upon bile salts depletion, and recovered bacteria displayed induced adherence to HT-29 cells. RNA-sequencing analysis verified an important bile salt transcriptional profile in S. flexneri 2457T, including induced drug resistance and virulence gene expression. Finally, functional mutagenesis identified the importance of the AcrAB efflux pump and lipopolysaccharide O-antigen synthesis for bile salt resistance. Our data demonstrate that S. flexneri 2457T employs multiple mechanisms to survive exposure to bile salts, which may have important implications for multidrug resistance. Furthermore, our work confirms that bile salts are important physiological signals to activate S. flexneri 2457T virulence. This work provides insights into how exposure to bile likely regulates Shigella survival and virulence during host transit and subsequent colonic infection.}, } @article {pmid28343055, year = {2017}, author = {Ahmad, M and Liu, S and Mahmood, N and Mahmood, A and Ali, M and Zheng, M and Ni, J}, title = {Effects of porous carrier size on biofilm development, microbial distribution and nitrogen removal in microaerobic bioreactors.}, journal = {Bioresource technology}, volume = {234}, number = {}, pages = {360-369}, doi = {10.1016/j.biortech.2017.03.076}, pmid = {28343055}, issn = {1873-2976}, mesh = {Ammonia/*isolation & purification ; Anaerobiosis ; Biodegradation, Environmental ; Biofilms/*growth & development ; Bioreactors/microbiology ; Denitrification ; Planctomycetales/*physiology ; Polyurethanes/chemistry ; Porosity ; Surface Properties ; Wastewater ; Water Purification ; }, abstract = {In this study, effects of porous carrier's size (polyurethane-based) on microbial characteristics were systematically investigated in addition to nitrogen removal performance in six microaerobic bioreactors. Among different sized carriers (50, 30, 20, 15,10, 5mm), 15mm carrier showed highest nitrogen removal (98%) due to optimal micro-environments created for aerobic nitrifiers in outer layer (0-7mm), nitrifiers and denitrifiers in middle layer (7-10mm) and anaerobic denitrifiers in inner layer (10-15mm). Candidatus brocadia, a dominant anammox bacteria, was solely concentrated close to centroid (0-70μm) and strongly co-aggregated with other bacterial communities in the middle layer of the carrier. Contrarily, carriers with a smaller (<15mm) or larger size (>15mm) either destroy the effective zone for anaerobic denitrifiers or damage the microaerobic environments due to poor mass transfer. This study is of particular use for optimal design of carriers in enhancing simultaneous nitrification-denitrification in microaerobic wastewater treatment processes.}, } @article {pmid28342310, year = {2017}, author = {Pallavicini, P and Arciola, CR and Bertoglio, F and Curtosi, S and Dacarro, G and D'Agostino, A and Ferrari, F and Merli, D and Milanese, C and Rossi, S and Taglietti, A and Tenci, M and Visai, L}, title = {Silver nanoparticles synthesized and coated with pectin: An ideal compromise for anti-bacterial and anti-biofilm action combined with wound-healing properties.}, journal = {Journal of colloid and interface science}, volume = {498}, number = {}, pages = {271-281}, doi = {10.1016/j.jcis.2017.03.062}, pmid = {28342310}, issn = {1095-7103}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Escherichia coli/drug effects ; Fibroblasts/cytology/drug effects ; Humans ; Metal Nanoparticles/*chemistry ; Particle Size ; Pectins/*chemistry/pharmacology ; Plankton/cytology/drug effects ; Silver/*chemistry/pharmacology ; Silver Nitrate/pharmacology ; Staphylococcus epidermidis/drug effects ; Surface Properties ; Wound Healing/*drug effects ; }, abstract = {The synthesis of Ag nanoparticles from Ag[+] has been investigated, with pectin acting both as reductant and coating.∼100% Ag[+] to Ag(0) one-pot conversion was obtained, yielding p-AgNP, i.e. an aqueous solution of pectin-coated spherical Ag nanoparticles (d=8.0±2.6nm), with a<1ppm concentration of free Ag[+] cation. Despite the low free Ag[+] concentration and low Ag[+] release with time, the nature of the coating allows p-AgNP to exert excellent antibacterial and antibiofilm actions, comparable to those of ionic silver, tested on E. coli (Gram-) and S. epidermidis (Gram+) both on planctonic cells and on pre- and post-biofilm formation conditions. Moreover, p-AgNP were tested on fibroblasts: not only p-AgNP were found to be cytocompatible but also revealed capable of promoting fibroblasts proliferation and to be effective for wound healing on model cultures. The antibacterial activity and the wound healing ability of silver nanoparticles are two apparently irreconcilable properties, as the former usually requires a high sustained Ag[+] release while the latter requires low Ag[+] concentration. p-AgNP represents an excellent compromise between opposite requirements, candidating as an efficient medication for repairing wounds and/or to treat vulnerable surgical site tissues, including the pre-treatment of implants as an effective prophylaxis in implant surgery.}, } @article {pmid28340187, year = {2018}, author = {Angiolella, L and Leone, C and Rojas, F and Mussin, J and de Los Angeles Sosa, M and Giusiano, G}, title = {Biofilm, adherence, and hydrophobicity as virulence factors in Malassezia furfur.}, journal = {Medical mycology}, volume = {56}, number = {1}, pages = {110-116}, doi = {10.1093/mmy/myx014}, pmid = {28340187}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; *Cell Adhesion ; Formazans/analysis ; Humans ; *Hydrophobic and Hydrophilic Interactions ; Malassezia/chemistry/*pathogenicity/physiology ; Microscopy, Electron, Scanning ; Virulence Factors/*analysis ; }, abstract = {Malassezia species are natural inhabitants of the healthy skin. However, under certain conditions, they may cause or exacerbate several skin diseases. The ability of this fungus to colonize or infect is determined by complex interactions between the fungal cell and its virulence factors. This study aims to evaluate "in vitro" the hydrophobicity levels, the adherence on a plastic surface and the biofilm formation of 16 clinical isolates of Malassezia furfur. Cellular surface hydrophobicity (CSH) levels were determined by two-phase system. The biofilm formation was determined by tetrazolium salt (XTT) reduction assay and by Scanning Electron Microscopy (SEM). Results showed many isolates were hydrophobic, adherent, and producers of biofilm on abiotic surfaces with different capacity. SEM observations confirmed an abundant extracellular matrix after 48 h of biofilm formation. About 63% of strains with high production of biofilm showed medium to high percentage of hydrophobicity and/or adherence. In addition, it has been demonstrated a correlation between hydrophobicity, adherence, and biofilm formation in about 60% of strains examined. These important virulence factors could be responsible of this yeast changing from a commensal to a pathogenic status.}, } @article {pmid28339699, year = {2017}, author = {Maharjan, P and Huff, G and Zhang, W and Watkins, S}, title = {Effects of chlorine and hydrogen peroxide sanitation in low bacterial content water on biofilm formation model of poultry brooding house waterlines.}, journal = {Poultry science}, volume = {96}, number = {7}, pages = {2145-2150}, doi = {10.3382/ps/pex009}, pmid = {28339699}, issn = {1525-3171}, mesh = {*Animal Husbandry ; Animals ; Biofilms/*drug effects ; Chlorine/*pharmacology ; Disinfectants/*pharmacology ; *Disinfection ; Housing, Animal ; Hydrogen Peroxide/*pharmacology ; Polyvinyl Chloride/chemistry ; Poultry ; United States ; *Water Microbiology ; Water Supply ; }, abstract = {An in vitro experiment was performed to determine if biofilm would develop when polyvinylchloride (PVC) test coupons (material used for poultry waterlines) were exposed to low bacterial content warm water (≤1000 cfu/mL, test water) and also to determine if biofilm development would be influenced by adding a sanitizer. PVC sections 2.54 cm long and internal diameter of 1. 90 cm were used as test coupons to grow biofilm. Two coupons were immersed in 600 mL test water in a beaker. Nine beakers were utilized similarly with a total of 18 coupons. Three beakers (T1) were treated with a chlorine (Cl) based product (targeted to produce 2 to 4 ppm residual) and the other 3 (T2) with hydrogen peroxide a (HP) based product (targeted to produce 25 to 50 ppm residual). Three untreated beakers served as controls (T3). All beakers and coupons were placed into a water bath shaker under warm and moving water conditions mimicking poultry brooding conditions. Coupons and test water were sampled for treatments for aerobic plate count (APC). Trial 1 used test water with zero cfu bacteria/mL initial APC, whereas the Trial 2 test water initial APC was 3 log10 cfu/mL. Test water samples and coupons had no bacterial growth for all treatments on sampling occasions for Trial 1. In Trial 2, T3 (control) and T2 (HP treated) had APC growth in both test water (2.5 to 3.0 log10 cfu/mL) and on coupons (2 to 2.5 log10 cfu/cm2) on sampling d with no difference (P > 0.05) between these treatments. Whereas, T1 (Cl treated) eliminated bacteria (zero cfu/mL) in test water and inhibited biofilm growth on test coupons (≤0.2 log10 cfu/cm2) during sampling d (P < 0.05). This experiment showed that biofilm can develop in minimally contaminated water even in the presence of sanitizers, yet chlorine was more effective than hydrogen peroxide in limiting this development.}, } @article {pmid28339292, year = {2017}, author = {Machado, D and Gaspar, C and Palmeira-de-Oliveira, A and Cavaleiro, C and Salgueiro, L and Martinez-de-Oliveira, J and Cerca, N}, title = {Thymbra capitata essential oil as potential therapeutic agent against Gardnerella vaginalis biofilm-related infections.}, journal = {Future microbiology}, volume = {12}, number = {}, pages = {407-416}, doi = {10.2217/fmb-2016-0184}, pmid = {28339292}, issn = {1746-0921}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Cymenes ; Flow Cytometry ; Gardnerella vaginalis/*drug effects/physiology ; Lactobacillus/drug effects ; Lamiaceae/*chemistry ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Monoterpenes/isolation & purification/*pharmacology ; Oils, Volatile/isolation & purification/*pharmacology ; Spectrophotometry ; }, abstract = {AIM: To evaluate the antibacterial activity of Thymbra capitata essential oil and its main compound, carvacrol, against Gardnerella vaginalis grown planktonically and as biofilms, and its effect of vaginal lactobacilli.

MATERIALS & METHODS: Minimal inhibitory concentration, minimal lethal concentration determination and flow cytometry analysis were used to assess the antibacterial effect against planktonic cells. Antibiofilm activity was measured through quantification of biomass and visualization of biofilm structure by confocal laser scanning microscopy.

RESULTS: T. capitata essential oil and carvacrol exhibited a potent antibacterial activity against G. vaginalis cells. Antibiofilm activity was more evident with the essential oil than carvacrol. Furthermore, vaginal lactobacilli were significantly more tolerant to the essential oil.

CONCLUSION: T. capitata essential oil stands up as a promising therapeutic agent against G. vaginalis biofilm-related infections.}, } @article {pmid28339291, year = {2017}, author = {Garcia-Nuñez, M and Marti, S and Puig, C and Perez-Brocal, V and Millares, L and Santos, S and Ardanuy, C and Moya, A and Liñares, J and Monsó, E}, title = {Bronchial microbiome, PA biofilm-forming capacity and exacerbation in severe COPD patients colonized by P. aeruginosa.}, journal = {Future microbiology}, volume = {12}, number = {}, pages = {379-392}, doi = {10.2217/fmb-2016-0127}, pmid = {28339291}, issn = {1746-0921}, mesh = {Biofilms/*growth & development ; Bronchi/*microbiology ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Humans ; *Microbiota ; Pseudomonas Infections/microbiology/*pathology ; Pseudomonas aeruginosa/*physiology ; Pulmonary Disease, Chronic Obstructive/*microbiology/pathology ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Sputum/microbiology ; }, abstract = {AIM: The bronchial microbiome of severe chronic obstructive pulmonary disease patients colonized by Pseudomonas aeruginosa was analyzed using 16S rRNA gene sequencing to identify differences related to biofilm-forming capacity.

PATIENTS & METHODS: Patient sputum samples from 21 patients were studied.

RESULTS: Statistically significant differences related to biofilm-forming capacity were only found for genera with relative abundances <1%, and Fusobacterium was over-represented when biofilm-forming capacity was high. Genera with relative abundances >50% which increased from baseline were observed in 10/14 exacerbations, but corresponded to Pseudomonas only in three episodes, while other pathogenic genera were identified in seven.

CONCLUSION: The bronchial microbiome shows differences according with P. aeruginosa biofilm-forming capacity. Pathogenic microorganisms other than P. aeruginosa cause a significant part of the exacerbations in colonized chronic obstructive pulmonary disease patients.}, } @article {pmid28338674, year = {2017}, author = {Wang, D and Xu, A and Elmerich, C and Ma, LZ}, title = {Biofilm formation enables free-living nitrogen-fixing rhizobacteria to fix nitrogen under aerobic conditions.}, journal = {The ISME journal}, volume = {11}, number = {7}, pages = {1602-1613}, pmid = {28338674}, issn = {1751-7370}, mesh = {Aerobiosis ; Biofilms/growth & development ; Carbon ; Nitrogen/*metabolism ; Nitrogen Fixation/*physiology ; Nitrogenase/metabolism ; Oxygen ; Pseudomonas stutzeri/*metabolism ; }, abstract = {The multicellular communities of microorganisms known as biofilms are of high significance in agricultural setting, yet it is largely unknown about the biofilm formed by nitrogen-fixing bacteria. Here we report the biofilm formation by Pseudomonas stutzeri A1501, a free-living rhizospheric bacterium, capable of fixing nitrogen under microaerobic and nitrogen-limiting conditions. P. stutzeri A1501 tended to form biofilm in minimal media, especially under nitrogen depletion condition. Under such growth condition, the biofilms formed at the air-liquid interface (termed as pellicles) and the colony biofilms on agar plates exhibited nitrogenase activity in air. The two kinds of biofilms both contained large ovoid shape 'cells' that were multiple living bacteria embedded in a sac of extracellular polymeric substances (EPSs). We proposed to name such large 'cells' as A1501 cyst. Our results suggest that the EPS, especially exopolysaccharides enabled the encased bacteria to fix nitrogen while grown under aerobic condition. The formation of A1501 cysts was reversible in response to the changes of carbon or nitrogen source status. A1501 cyst formation depended on nitrogen-limiting signaling and the presence of sufficient carbon sources, yet was independent of an active nitrogenase. The pellicles formed by Azospirillum brasilense, another free-living nitrogen-fixing rhizobacterium, which also exhibited nitrogenase activity and contained the large EPS-encapsuled A1501 cyst-like 'cells'. Our data imply that free-living nitrogen-fixing bacteria could convert the easy-used carbon sources to exopolysaccharides in order to enable nitrogen fixation in a natural aerobic environment.}, } @article {pmid28338673, year = {2017}, author = {Yan, J and Nadell, CD and Bassler, BL}, title = {Environmental fluctuation governs selection for plasticity in biofilm production.}, journal = {The ISME journal}, volume = {11}, number = {7}, pages = {1569-1577}, pmid = {28338673}, issn = {1751-7370}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Biofilms/*growth & development ; Ecosystem ; Genetic Fitness ; Vibrio cholerae/genetics/*physiology ; }, abstract = {Bacteria can grow in a free-swimming state, as planktonic cells, or in surface-attached communities, termed biofilms. The planktonic and biofilm growth modes differ dramatically with respect to spatial constraints, nutrient access, population density and cell-cell interactions. Fitness trade-offs underlie how successfully bacteria compete in each of these environments. Accordingly, some bacteria have evolved to be specialists in biofilm formation, while others specialize in planktonic growth. There are species, however, that possess flexible strategies: they can transition between the molecular programs required for biofilm formation and for planktonic growth. Such flexible strategies often sacrifice competitive ability against specialists in a given habitat. There is little exploration of the ecological conditions favoring the evolution of the flexible biofilm production strategy for bacteria in competition with specialist biofilm producers or specialist non-producers. Here, we study the human pathogen Vibrio cholerae, a flexible biofilm-former, as well as constitutive biofilm-producing and non-producing mutants. We assess the fitness of these strains under biofilm conditions, planktonic conditions and conditions that demand the ability to transition between the two growth modes. We show that, relative to the specialists, the wild type is superior at dispersal from biofilms to the planktonic phase; however, this capability comes at the expense of reduced competitive fitness against constitutive biofilm producers on surfaces. Wild-type V. cholerae can outcompete the constitutive biofilm producers and non-producers if habitat turnover is sufficiently frequent. Thus, selection for phenotypic flexibility in biofilm production depends on the frequency of environmental fluctuations encountered by bacteria.}, } @article {pmid28337637, year = {2017}, author = {Cattana, ME and Tracogna, MF and Marques, I and Rojas, F and Fernández, M and de Los Ángeles Sosa, M and Mussin, J and Giusiano, G}, title = {In Vivo Paracoccidioides sp. Biofilm on Vascular Prosthesis.}, journal = {Mycopathologia}, volume = {182}, number = {7-8}, pages = {747-749}, pmid = {28337637}, issn = {1573-0832}, mesh = {Biofilms/*growth & development ; Blood Vessel Prosthesis/*microbiology ; Humans ; Latin America ; Male ; Microscopy, Electron, Scanning ; Paracoccidioides/*isolation & purification/*physiology ; Paracoccidioidomycosis/*diagnosis/microbiology ; Prosthesis-Related Infections/*diagnosis/microbiology ; }, abstract = {Paracoccidioidomycosis is an endemic mycosis caused by Paracoccidioides species limited to Latin America arising with the chronic form in 90% of cases. The capacity of microorganisms to form biofilms is considered of great importance medical since can contribute to the persistence and to the chronic state of the diseases. The ability of Paracoccidioides to form biofilm has been demonstrated in vitro. In our study, for the first time we have observed this capability in vivo on a vascular prosthesis using scanning electron microscope showing a dense network of Paracoccidioides yeasts covered by an extracellular matrix.}, } @article {pmid28335808, year = {2017}, author = {Wu, X and Pedersen, K and Edlund, J and Eriksson, L and Åström, M and Andersson, AF and Bertilsson, S and Dopson, M}, title = {Potential for hydrogen-oxidizing chemolithoautotrophic and diazotrophic populations to initiate biofilm formation in oligotrophic, deep terrestrial subsurface waters.}, journal = {Microbiome}, volume = {5}, number = {1}, pages = {37}, pmid = {28335808}, issn = {2049-2618}, mesh = {Betaproteobacteria/classification/*genetics ; Biofilms/*classification ; Chemoautotrophic Growth/*genetics/physiology ; Deltaproteobacteria/classification/*genetics ; Epsilonproteobacteria/classification/*genetics ; Extreme Environments ; Groundwater/microbiology ; Hydrogen/chemistry ; Metagenome ; Nitrogen Fixation/*genetics/physiology ; Oceans and Seas ; Oxidation-Reduction ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Verrucomicrobia/classification/*genetics ; Water Microbiology ; }, abstract = {BACKGROUND: Deep terrestrial biosphere waters are separated from the light-driven surface by the time required to percolate to the subsurface. Despite biofilms being the dominant form of microbial life in many natural environments, they have received little attention in the oligotrophic and anaerobic waters found in deep bedrock fractures. This study is the first to use community DNA sequencing to describe biofilm formation under in situ conditions in the deep terrestrial biosphere.

RESULTS: In this study, flow cells were attached to boreholes containing either "modern marine" or "old saline" waters of different origin and degree of isolation from the light-driven surface of the earth. Using 16S rRNA gene sequencing, we showed that planktonic and attached populations were dissimilar while gene frequencies in the metagenomes suggested that hydrogen-fed, carbon dioxide- and nitrogen-fixing populations were responsible for biofilm formation across the two aquifers. Metagenome analyses further suggested that only a subset of the populations were able to attach and produce an extracellular polysaccharide matrix. Initial biofilm formation is thus likely to be mediated by a few bacterial populations which were similar to Epsilonproteobacteria, Deltaproteobacteria, Betaproteobacteria, Verrucomicrobia, and unclassified bacteria.

CONCLUSIONS: Populations potentially capable of attaching to a surface and to produce extracellular polysaccharide matrix for attachment were identified in the terrestrial deep biosphere. Our results suggest that the biofilm populations were taxonomically distinct from the planktonic community and were enriched in populations with a chemolithoautotrophic and diazotrophic metabolism coupling hydrogen oxidation to energy conservation under oligotrophic conditions.}, } @article {pmid28334551, year = {2017}, author = {Chang, S and Chen, X and Jiang, S and Chen, J and Shi, L}, title = {Using micro-patterned surfaces to inhibit settlement and biofilm formation by Bacillus subtilis.}, journal = {Canadian journal of microbiology}, volume = {63}, number = {7}, pages = {608-620}, doi = {10.1139/cjm-2016-0463}, pmid = {28334551}, issn = {1480-3275}, mesh = {Bacillus subtilis/*growth & development/ultrastructure ; Biofilms/*growth & development ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Microtechnology ; Surface Properties ; }, abstract = {Biofilm is a biological complex caused by bacteria attachment to the substrates and their subsequent reproduction and secretion. This phenomenon reduces heat transfer efficiency and causes significant losses in treated sewage heat-recovering systems. This paper describes a physical approach to inhibit bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant species in treated sewage. Here, micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1-100 μm) were fabricated as surfaces of interest. Model sewage was prepared and a rotating coupon device was used to form the biofilms. Precision balance, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) were employed to investigate the inhibitory effects and the mechanisms of the biofilm-surface interactions. The results have shown that surfaces with small pattern sizes (1 and 2 μm) all reduced biofilm formation significantly. Interestingly, the CLSM images showed that the surfaces do not play a role in "killing" the bacteria. These findings are useful for future development of new process surfaces on which bacteria settlement and biofilm formation can be inhibited or minimized.}, } @article {pmid28334216, year = {2017}, author = {Kato, F and Yabuno, Y and Yamaguchi, Y and Sugai, M and Inouye, M}, title = {Deletion of mazF increases Staphylococcus aureus biofilm formation in an ica-dependent manner.}, journal = {Pathogens and disease}, volume = {75}, number = {5}, pages = {}, doi = {10.1093/femspd/ftx026}, pmid = {28334216}, issn = {2049-632X}, mesh = {Amino Acid Substitution ; Biofilms/*growth & development ; DNA Mutational Analysis ; *Gene Deletion ; Gene Expression Profiling ; *Genes, Bacterial ; Genetic Complementation Test ; Polysaccharides, Bacterial/biosynthesis ; Staphylococcus aureus/genetics/*physiology ; *Toxin-Antitoxin Systems ; }, abstract = {Toxin-antitoxin (TA) systems are composed of a toxin that inhibits an essential cellular process (e.g. DNA replication, transcription, membrane integrity) and its cognate antitoxin that neutralizes the effect of the toxin. Staphylococcus aureus harbors two types of chromosomally encoded TA systems, namely mazEFsa encoding a UACAU-specific mRNA interferase and two paralogous genes of yefM-yoeBsa encoding a ribosome-dependent endoribonuclease system. However, little is known about the physiological role of MazEFsa and YefM-YoeBsa in S. aureus. Upon characterizing the phenotypes of single, double and triple gene deletion mutants, we found that mazFsa deletion led to increased biofilm formation. Subsequently, transcriptional analysis revealed that expression of intercellular adhesin (ica) gene, icaADBC, increased in a mazFsa deletion mutant. mazFsa/icaADBC double gene deletion and genetic complementation approaches provided convincing evidence that increased biofilm formation was caused by an increase in polysaccharide intercellular adhesin synthesized by icaADBC-encoded proteins. Furthermore, through the use of alanine substitutions at the conserved active residues of MazFsa, our results suggested that ica-mediated biofilm formation depended on the mRNA interferase activity of MazFsa. These findings give new insights not only into the physiological role of MazEFsa in S. aureus, but also into the regulatory mechanism of ica-dependent biofilm formation.}, } @article {pmid28334109, year = {2017}, author = {Puzon, GJ and Wylie, JT and Walsh, T and Braun, K and Morgan, MJ}, title = {Comparison of biofilm ecology supporting growth of individual Naegleria species in a drinking water distribution system.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {4}, pages = {}, doi = {10.1093/femsec/fix017}, pmid = {28334109}, issn = {1574-6941}, mesh = {Bacteria ; Biofilms/*growth & development ; Drinking Water/microbiology/*parasitology ; Ecology ; Naegleria/*physiology ; Naegleria fowleri ; }, abstract = {Free-living amoebae (FLA) are common components of microbial communities in drinking water distribution systems (DWDS). FLA are of clinical importance both as pathogens and as reservoirs for bacterial pathogens, so identifying the conditions promoting amoebae colonisation of DWDSs is an important public health concern for water utilities. We used high-throughput amplicon sequencing to compare eukaryotic and bacterial communities associated with DWDS biofilms supporting distinct FLA species (Naegleria fowleri, N. lovaniensis or Vermamoeba sp.) at sites with similar physical/chemical conditions. Eukaryote and bacterial communities were characteristics of different FLA species presence, and biofilms supporting Naegleria growth had higher bacterial richness and higher abundance of Proteobacteria, Bacteroidetes (bacteria), Nematoda and Rotifera (eukaryota). The eukaryotic community in the biofilms had the greatest difference in relation to the presence of N. fowleri, while the bacterial community identified individual bacterial families associated with the presence of different Naegleria species. Our results demonstrate that ecogenomics data provide a powerful tool for studying the microbial and meiobiotal content of biofilms, and, in these samples can effectively discriminate biofilm communities supporting pathogenic N. fowleri. The identification of microbial species associated with N. fowleri could further be used in the management and control of N. fowleri in DWDS.}, } @article {pmid28332593, year = {2017}, author = {Wang, Y and Leng, V and Patel, V and Phillips, KS}, title = {Injections through skin colonized with Staphylococcus aureus biofilm introduce contamination despite standard antimicrobial preparation procedures.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {45070}, pmid = {28332593}, issn = {2045-2322}, mesh = {Animals ; Anti-Infective Agents/*pharmacology ; *Biofilms ; Disease Models, Animal ; Humans ; Staphylococcal Infections/*microbiology ; Staphylococcal Skin Infections/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; Swine ; }, abstract = {While surgical site preparation has been extensively studied, there is little information about resistance of skin microbiota in the biofilm form to antimicrobial decontamination, and there are no quantitative models to study how biofilm might be transferred into sterile tissue/implant materials during injections for joint spine and tendon, aspiration biopsies and dermal fillers (DF). In this work, we develop two in vitro models to simulate the process of skin preparation and DF injection using pig skin and SimSkin (silicone) materials, respectively. Using the pig skin model, we tested three of the most common skin preparation wipes (alcohol, chlorhexidine and povidone iodine) and found that during wiping they reduced the biofilm bacterial burden of S. aureus (CFU cm[-2]) by three logs with no statistically significant differences between wipes. Using the SimSkin model, we found that transfer of viable bacteria increased with needle diameter for 30G, 25G and 18G needles. Transfer incidence decreased as injection depth was increased from 1 mm to 3 mm. Serial puncture and linear threading injection styles had similar transfer incidence, whereas fanning significantly increased transfer incidence. The results show that contamination of DF during injection is a risk that can be reduced by modifying skin prep and injection practices.}, } @article {pmid28330748, year = {2017}, author = {Vijayakumar, S and Malaikozhundan, B and Shanthi, S and Vaseeharan, B and Thajuddin, N}, title = {Control of biofilm forming clinically important bacteria by green synthesized ZnO nanoparticles and its ecotoxicity on Ceriodaphnia cornuta.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {88-97}, doi = {10.1016/j.micpath.2017.03.019}, pmid = {28330748}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Arthropods/*microbiology ; Bacteria/*drug effects ; Biofilms/*drug effects/growth & development ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Models, Animal ; Nanoparticles/*chemistry ; Particle Size ; Plant Extracts/chemistry/pharmacology ; Plant Leaves/chemistry ; Plectranthus/chemistry ; Spectrometry, X-Ray Emission ; Zinc Oxide/administration & dosage/chemistry/*pharmacology ; }, abstract = {Zinc oxide nanoparticles were synthesized using the aqueous leaf extracts of Plectranthus barbatus (Plb-ZnO NPs) and characterized by UV-visible spectroscopy, XRD, FTIR, SEM and EDS. UV-Visible spectra recorded the absorbance peak of Plb-ZnO NPs at 343 nm. SEM analyses showed the spherical shape of Plb-ZnO NPs with the particle size between 30 and 60 nm. Plb-ZnO NPs exhibited antibacterial and antibiofilm activity against Gram positive Bacillus subtilis at all tested concentrations. In contrast, Plb-ZnO NPs showed antibacterial and antibiofilm activity against Gram negative Vibrio parahaemolyticus and Proteus vulgaris only at 100 μg/ml. The Atomic absorption spectrometry (AAS) revealed that Zn[2+] dissolution was 1.87 and 8.8 μg/L at 10 and 160 μg/L of Plb-ZnO NPs respectively. The body accumulation of Zn[2+] was increased from 0.8 μg/g body weight to 3.5 μg/g body weight when C. cornuta exposed to 10 μg/L and 160 μg/L respectively. Plb-ZnO NPs were toxic to Ceriodaphnia cornuta neonates (LC50: 28 μg/L). Plb-ZnO NPs caused 100% mortality of C. cornuta at 160 μg/L after 24 h. However, zinc acetate does not cause any mortality of C. cornuta upto 350 μg/L. The light and confocal laser scanning microscopic images evidenced the uptake and accumulation of Plb-ZnO NPs on the internal gut regions of C. cornuta at 160 μg/L after 5, 10, 15, 20 and 24 h. Abnormalities in the swimming behaviour such as erratic swimming (ERR), migration to bottom (BOT) and migration to water surface (SUR) of C. cornuta were noticed after treatment with different concentrations of Plb-ZnO NPs.}, } @article {pmid28330484, year = {2017}, author = {Belbase, A and Pant, ND and Nepal, K and Neupane, B and Baidhya, R and Baidya, R and Lekhak, B}, title = {Antibiotic resistance and biofilm production among the strains of Staphylococcus aureus isolated from pus/wound swab samples in a tertiary care hospital in Nepal.}, journal = {Annals of clinical microbiology and antimicrobials}, volume = {16}, number = {1}, pages = {15}, pmid = {28330484}, issn = {1476-0711}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; Cross-Sectional Studies ; *Drug Resistance, Bacterial ; Humans ; Nepal/epidemiology ; Staphylococcal Infections/epidemiology/*microbiology ; Staphylococcus aureus/*drug effects/isolation & purification/*physiology ; Suppuration/microbiology ; Tertiary Care Centers ; Wound Infection/epidemiology/*microbiology ; }, abstract = {BACKGROUND: The increasing drug resistance along with inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of Staphylococcus aureus are present as the serious problems to the successful treatment of the infections caused by S. aureus. So, the main objectives of this study were to determine the antimicrobial susceptibility patterns along with the rates of inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of S. aureus isolated from pus/wound swab samples.

METHODS: A total of 830 non-repeated pus/wound swab samples were processed using standard microbiological techniques. The colonies grown were identified on the basis of colony morphology, Gram's stain and biochemical tests. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion technique. Detection of inducible clindamycin resistance was performed by D test, while detection of methicillin resistant S. aureus (MRSA) was performed by determination of minimum inhibitory concentration of oxacillin by agar dilution method. Similarly, detection of biofilm formation was performed by microtiter plate method. Strains showing resistance to three or more than three different classes of antibiotics were considered multidrug resistant.

RESULTS: Total 76 samples showed the growth of S. aureus, among which 36 (47.4%) contained MRSA and 17 (22.4%) samples were found to have S. aureus showing inducible clindamycin resistance. Among the S. aureus isolated from outpatients, 41.9% were MRSA. Highest rates of susceptibility of S. aureus were seen toward linezolid (100%) and vancomycin (100%). Similarly, S. aureus isolated from 35 (46.1%) samples were found to be biofilm producers. Higher rate of inducible clindamycin resistance was seen among MRSA in comparison to methicillin susceptible S. aureus (MSSA). Similarly, higher rates of multidrug resistance and methicillin resistance were found among biofilm producing strains in comparison to biofilm non producing strains.

CONCLUSIONS: The rate of isolation of MRSA from community acquired infections was found to be high in Nepal. Increased rate of inducible clindamycin resistance as compared to previous studies in Nepal was noted. So for the proper management of the infections caused by S. aureus, D test for the detection of inducible clindamycin resistance should be included in the routine laboratory diagnosis. Further, detection of biofilm production should also be included in the routine tests. Linezolid and vancomycin can be used for the preliminary treatment of the serious infections caused by S. aureus.}, } @article {pmid28327271, year = {2017}, author = {Zapotoczna, M and Boksmati, N and Donohue, S and Bahtiar, B and Boland, A and Somali, HA and Cox, A and Humphreys, H and O'Gara, JP and Brennan, M and O'Neill, E}, title = {Novel anti-staphylococcal and anti-biofilm properties of two anti-malarial compounds: MMV665953 {1-(3-chloro-4-fluorophenyl)-3-(3,4-dichlorophenyl)urea} and MMV665807 {5-chloro-2-hydroxy-N-[3-(trifluoromethyl)phenyl]benzamide} .}, journal = {Journal of medical microbiology}, volume = {66}, number = {3}, pages = {377-387}, doi = {10.1099/jmm.0.000446}, pmid = {28327271}, issn = {1473-5644}, mesh = {Antimalarials/*pharmacology ; Benzamides/*pharmacology ; Biofilms/*drug effects ; Humans ; Inhibitory Concentration 50 ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Phenylurea Compounds/*pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {PURPOSE: The treatment of device-related infections is challenging and current anti-microbial compounds have poor anti-biofilm activity. We aimed to identify and characterize novel compounds effective in the eradication of Staphylococcus aureus biofilms.

METHODOLOGY: Two novel compounds, MMV665953 {1-(3-chloro-4-fluorophenyl)-3-(3,4-dichlorophenyl)urea} and MMV665807{5-chloro-2-hydroxy-N-[3-(trifluoromethyl)phenyl]benzamide}, effective in killing S. aureus biofilms, were identified by screening of the open access 'malaria box' chemical library. The minimum bactericidal concentrations, half-maximal inhibition concentration (IC50) values and minimal biofilm killing concentrations effective in the killing of biofilm were determined against meticillin-resistant S. aureus and meticillin-sensitive S. aureus. Fibrin-embedded biofilms were grown under in vivo-relevant conditions, and viability was measured using a resazurin-conversion assay and confocal microscopy. The potential for the development of resistance and cytotoxicity was also assessed.

RESULTS: MMV665953 and MMV665807 were bactericidal against S. aureus isolates. The IC50 against S. aureus biofilms was at 0.15-0.58 mg l-1 after 24 h treatment, whereas the concentration required to eradicate all tested biofilms was 4 mg l-1, making the compounds more bactericidal than conventional antibiotics. The cytotoxicity against human keratinocytes and primary endothelial cells was determined as IC50 7.47 and 0.18 mg l-1 for MMV665953, and as 1.895 and 0.076 mg l-1 for MMV665807. Neither compound was haemolytic nor caused platelet activation. MMV665953 and MMV665807 derivatives with reduced cytotoxicity exhibited a concomitant loss in anti-staphylococcal activity.

CONCLUSION: MMV665953 and MMV665807 are more bactericidal against S. aureus biofilms than currently used anti-staphylococcal antibiotics and represent a valuable structural basis for further investigation in the treatment of staphylococcal biofilm-related infections.}, } @article {pmid28327128, year = {2017}, author = {Aksit Bıcak, D and Akyuz, S and Kıratlı, B and Usta, M and Urganci, N and Alev, B and Yarat, A and Sahin, F}, title = {The investigation of Helicobacter pylori in the dental biofilm and saliva samples of children with dyspeptic complaints.}, journal = {BMC oral health}, volume = {17}, number = {1}, pages = {67}, pmid = {28327128}, issn = {1472-6831}, mesh = {Adolescent ; *Biofilms ; Biopsy ; Case-Control Studies ; Child ; Child, Preschool ; DMF Index ; Dyspepsia/*microbiology ; Female ; Gastroscopy ; Halitosis/microbiology ; Helicobacter pylori/*isolation & purification ; Humans ; Male ; Periodontal Index ; Real-Time Polymerase Chain Reaction ; Saliva/*microbiology ; Surveys and Questionnaires ; Turkey ; }, abstract = {BACKGROUND: The oral cavity can be an extra-gastric reservoir for Helicobacter pylori (H.pylori). This can play a role in the pathogenesis of halitosis, glossitis, recurrent aphthous stomatitis, and dental caries. The present study was conducted to detect the presence of H.pylori within the dental biofilm and in saliva samples collected from children suffering from dyspepsia and children without any gastrointestinal complaints. Associations with gastric infection, halitosis, and some oral parameters were also evaluated.

METHODS: Seventy children (aged between 5-16) with dyspepsia were selected for the study group and control group composed of 30 healthy children without dyspepsia were also included in the study. After detailed oral and clinical examinations for oral parameters, saliva, and supragingival dental biofilm samples were collected for 16S rRNA and 23S rRNA genes detection by real-time polymerase chain reaction (RT-PCR). The presence of gastric H.pylori was evaluated in endoscopic biopsy specimens histopathologically. Halitosis was evaluated by benzoyl-DL-arginine-naphthylamid (BANA) test. Salivary S.mutans and Lactobacilli sp. counts were also carried out by commercial kits.

RESULTS: H.pylori was histopathologically detected amongst 83% of the children with the dyspeptic condition. The detection rate of this bacteria in dental biofilm and saliva samples and halitosis were found relatively higher in the dyspeptic children rather than the control group (p < 0.01). Halitosis was not significantly different between dyspeptic children and those detected with H.pylori (p > 0.05). In the gastric H.pylori positive group with dyspepsia, DMFT/S and dmft/s numbers and plaque indices were found higher than the control group (p < 0.01). Only plaque indices of gastric H.pylori negative group with dyspepsia were found higher than the control group (p < 0.01). S.mutans and Lactobacilli sp. counts were not significantly different between gastric H.pylori positive and negative groups (p > 0.05). Comparing to those with negative for both genes, in children whose dental biofilm and saliva samples were positive for both 16S rRNA and 23S rRNA genes, significantly higher results for halitosis, and DMFS numbers and significantly lower results for dmfs numbers and pH values were found (p < 0.01).

CONCLUSIONS: Helicobacter pylori can occur in the oral cavity aside and independently from the stomach. However, the high number of bacteria in the oral cavities of children with gastric H.pylori, an association between the presence of H.pylori and halitosis, DMFS, and pH were found.}, } @article {pmid28325766, year = {2017}, author = {Herrera, A and Kulhankova, K and Sonkar, VK and Dayal, S and Klingelhutz, AJ and Salgado-Pabón, W and Schlievert, PM}, title = {Staphylococcal β-Toxin Modulates Human Aortic Endothelial Cell and Platelet Function through Sphingomyelinase and Biofilm Ligase Activities.}, journal = {mBio}, volume = {8}, number = {2}, pages = {}, pmid = {28325766}, issn = {2150-7511}, support = {R01 AI032135/AI/NIAID NIH HHS/United States ; T32 AI007511/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Toxins/genetics/*metabolism ; Biofilms/growth & development ; Blood Platelets/*drug effects ; CD40 Antigens/analysis ; Cell Membrane/drug effects/ultrastructure ; Cell Survival/drug effects ; Cells, Cultured ; Endothelial Cells/chemistry/*drug effects ; Hemolysin Proteins/genetics/*metabolism ; *Host-Pathogen Interactions ; Humans ; Ligases/*metabolism ; Mutant Proteins/genetics/metabolism ; Recombinant Proteins/genetics/metabolism ; Sphingomyelin Phosphodiesterase/genetics/*metabolism ; Staphylococcus aureus/*pathogenicity ; Vascular Cell Adhesion Molecule-1/analysis ; }, abstract = {Staphylococcus aureus causes many infections, such as skin and soft tissue, pneumonia, osteomyelitis, and infective endocarditis (IE). IE is an endovascular infection of native and prosthetic valves and the lining of the heart; it is characterized by the formation of cauliflower-like "vegetations" composed of fibrin, platelets, other host factors, bacteria, and bacterial products. β-Toxin is an S. aureus virulence factor that contributes to the microorganism's ability to cause IE. This cytolysin has two enzymatic activities: sphingomyelinase (SMase) and biofilm ligase. Although both activities have functions in a rabbit model of IE, the mechanism(s) by which β-toxin directly affects human cells and is involved in the infectious process has not been elucidated. Here, we compared the in vitro effects of purified recombinant wild-type β-toxin, SMase-deficient β-toxin (H289N), and biofilm ligase-deficient β-toxin (H162A and/or D163A) on human aortic endothelial cells (HAECs) and platelets. β-Toxin was cytotoxic to HAECs and inhibited the production of interleukin 8 (IL-8) from these cells by both SMase and biofilm ligase activities. β-Toxin altered HAEC surface expression of CD40 and vascular cell adhesion molecule 1 (VCAM-1). HAECs treated with β-toxin displayed granular membrane morphology not seen in treatment with the SMase-deficient mutant. The altered morphology resulted in two possibly separable activities, cell rounding and redistribution of cell membranes into granules, which were not the result of endosome production from the Golgi apparatus or lysosomes. β-Toxin directly aggregated rabbit platelets via SMase activity.IMPORTANCE Each year there are up to 100,000 cases of infective endocarditis (IE) in the United States. S. aureus is the most common pathogen in patients with health care-associated IE and the leading cause of community-associated IE in the developed world. Multiple clonal group strains as defined by the Centers for Disease Control and Prevention, particularly USA200 and other clones encoding β-toxin, are highly associated with IE. Considering the strong association and established contribution of β-toxin in animal models of IE, determining how β-toxin directly affects human cell types, including endothelial cells and platelets, is important. In this study, we demonstrate that β-toxin functions to modulate endothelial cells and platelets by both toxin sphingomyelinase and biofilm ligase activities. Our data suggest that these activities modulate inflammation and increase infection severity.}, } @article {pmid28323149, year = {2017}, author = {Mahdiun, F and Mansouri, S and Khazaeli, P and Mirzaei, R}, title = {The effect of tobramycin incorporated with bismuth-ethanedithiol loaded on niosomes on the quorum sensing and biofilm formation of Pseudomonas aeruginosa.}, journal = {Microbial pathogenesis}, volume = {107}, number = {}, pages = {129-135}, doi = {10.1016/j.micpath.2017.03.014}, pmid = {28323149}, issn = {1096-1208}, mesh = {4-Butyrolactone/analogs & derivatives/pharmacology ; Agrobacterium tumefaciens/drug effects ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Bismuth/*pharmacology ; Drug Combinations ; Drug Resistance, Multiple, Bacterial/drug effects ; Liposomes/chemistry/*pharmacology ; Mercaptoethanol/*analogs & derivatives/pharmacology ; Microbial Sensitivity Tests ; Particle Size ; Pseudomonas aeruginosa/*drug effects/growth & development ; Quorum Sensing/*drug effects ; Tobramycin/*pharmacology ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen, enable of causing infections especially in immunocompromised patients. Recently many isolates developed multiple drug resistance, resulting in treatment failure in serious infections. In this study, the effect of tobramycin incorporated with bismuth-ethanedithiol loaded on niosomes on the quorum sensing and biofilm production by P. aeruginosa was evaluated. Thin layer hydration method with cholesterol (30%), Span 40 and Tween 40 were used to make niosomes. The physical properties and particle size of the niosomes were investigated. Micro dilution method was used to determine the Minimum Inhibitory Concentration (MIC) for tobramycin, niosomal tobramycin, bismuth ethanedithiol, niosomal bismuth ethanedithiol, tobramycin incorporated with bismuth-ethanedithiol and niosomal tobramycin incorporated with bismuth-ethanedithiol. Biofilm formation was evaluated using microtiter plate. The effect of different combination on N-acyl homoserine lactone (AHL) production was evaluated in presence of Agrobacterium tumefaciens strain (GV3101). The best combination inhibiting the growth of various strains of P. aeruginosa were niosomal tobramycin and niosomal tobramycin incorporated with bismuth-ethanedithiol which reduced the MIC of tobramycin significantly. Sub-MIC concentration of these compounds reduced the rate of biofilm formation 80% lower than the untreated bacteria, and effectively inhibited the production of AHL molecule. The prepared formulations containing non-ionic surfactants, can kept the drug and gradually release it. Encapsulation of tobramycin in combination with bismuth-ethanedithiol in niosome had the ability to reduce the MIC of tobramycin and effectively inhibiting the biofilm formation. These combinations can be used as an excellent combination for further evaluation for treatment of infections caused by MDR isolates of P. aeruginosa.}, } @article {pmid28322885, year = {2017}, author = {Al Dehailan, L and Lippert, F and González-Cabezas, C and Eckert, GJ and Martinez-Mier, EA}, title = {Fluoride concentration in saliva and biofilm fluid following the application of three fluoride varnishes.}, journal = {Journal of dentistry}, volume = {60}, number = {}, pages = {87-93}, doi = {10.1016/j.jdent.2017.03.005}, pmid = {28322885}, issn = {1879-176X}, mesh = {Biofilms/*drug effects ; Calcium Phosphates ; Child ; Cross-Over Studies ; Dental Caries/prevention & control ; Dental Enamel/drug effects ; Fluorides/*chemistry ; Fluorides, Topical/*chemistry/pharmacokinetics ; Humans ; Indiana ; Materials Testing ; Phosphates/*chemistry ; Saliva/*chemistry ; Sodium Fluoride ; Solubility ; Time Factors ; Toothpastes ; }, abstract = {OBJECTIVE: Most of the commercially available fluoride varnishes (FV) have not been evaluated for their cariostatic properties. Consequently, the aim of this in vivo study was to investigate intra-oral fluoride retention and clearance patterns from three different FV.

METHODS: Eighteen subjects (7-11 years) participated in a laboratory analyst-blinded, randomized, crossover study comparing the ability of 5% sodium fluoride varnishes (CavityShield-CS, Enamel Pro-EP, Vanish-V) to enhance fluoride concentrations in biofilm fluid, centrifuged and whole saliva over a period of 48h after a single FV application.

RESULTS: Similar fluoride concentration×time patterns were noted for all investigated FV and studied variables, with the highest fluoride concentrations observed for the first biological sample collected after FV application (30min). Mean±SE (area under fluoride clearance curve) values were (μg F/g or ml×min): biofilm fluid - CS (472±191), EP (423±75),V (1264±279); centrifuged saliva - CS (42±7), EP (19±3),V (41±8); whole saliva - CS (68±11), EP (64±10),V (60±7).V delivered more fluoride to biofilm fluid than CS (p=0.0116) and EP (p=0.0065), which did not differ (p=0.27). For centrifuged saliva, CS and V were not significantly different (p=0.86), but resulted in higher fluoride retention than EP (p<0.0008). No significant differences among FV were observed for whole saliva (p=0.79).

CONCLUSION: The present study has shown that FV vary in their ability to deliver fluoride intra-orally potentially related to formulation differences. To what extent the present findings relate to clinical efficacy remains, however, to be determined.

CLINICAL SIGNIFICANCE: Clinical research that investigates fluoride release patterns into saliva and biofilm fluid from different FV products is insufficient. More research is needed to investigate different FV formulations for their efficacy in order to help clinicians make better evidence based treatment choices.}, } @article {pmid28321487, year = {2017}, author = {van der Waals, MJ and Atashgahi, S and da Rocha, UN and van der Zaan, BM and Smidt, H and Gerritse, J}, title = {Benzene degradation in a denitrifying biofilm reactor: activity and microbial community composition.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {12}, pages = {5175-5188}, pmid = {28321487}, issn = {1432-0614}, mesh = {Anaerobiosis ; Bacteria/classification/drug effects/genetics/*metabolism ; Benzene/*metabolism/pharmacology ; Benzoic Acid/analysis ; *Biodegradation, Environmental ; Biofilms/drug effects/*growth & development ; Culture Media/chemistry ; *Denitrification ; Microbial Consortia/drug effects/genetics/*physiology ; Nitrates/metabolism ; Peptococcaceae/classification/genetics/isolation & purification/metabolism ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degradation reactions. Benzene was degraded at a rate of 0.15 μmol/mg protein/day and a first-order rate constant of 3.04/day which was fourfold higher than rates reported previously. Bacteria belonging to the Peptococcaceae were found to play an important role in this anaerobic benzene-degrading biofilm culture, but also members of the Anaerolineaceae were predicted to be involved in benzene degradation or benzene metabolite degradation based on Illumina MiSeq analysis of 16S ribosomal RNA genes. Biomass retention in the reactor using a filtration finger resulted in reduction of benzene degradation capacity. Detection of the benzene carboxylase encoding gene, abcA, and benzoic acid in the culture vessel indicated that benzene degradation proceeds through an initial carboxylation step.}, } @article {pmid28320940, year = {2017}, author = {Feuillie, C and Formosa-Dague, C and Hays, LM and Vervaeck, O and Derclaye, S and Brennan, MP and Foster, TJ and Geoghegan, JA and Dufrêne, YF}, title = {Molecular interactions and inhibition of the staphylococcal biofilm-forming protein SdrC.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {14}, pages = {3738-3743}, pmid = {28320940}, issn = {1091-6490}, mesh = {Bacterial Adhesion ; Bacterial Proteins/antagonists & inhibitors/chemistry/*metabolism ; Binding Sites ; *Biofilms ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Nerve Tissue Proteins/*chemistry ; Peptides/chemistry/*pharmacology ; Protein Binding ; Single-Cell Analysis ; Staphylococcus aureus/*physiology ; }, abstract = {Staphylococcus aureus forms biofilms on indwelling medical devices using a variety of cell-surface proteins. There is growing evidence that specific homophilic interactions between these proteins represent an important mechanism of cell accumulation during biofilm formation, but the underlying molecular mechanisms are still not well-understood. Here we report the direct measurement of homophilic binding forces by the serine-aspartate repeat protein SdrC and their inhibition by a peptide. Using single-cell and single-molecule force measurements, we find that SdrC is engaged in low-affinity homophilic bonds that promote cell-cell adhesion. Low-affinity intercellular adhesion may play a role in favoring biofilm dynamics. We show that SdrC also mediates strong cellular interactions with hydrophobic surfaces, which are likely to be involved in the initial attachment to biomaterials, the first stage of biofilm formation. Furthermore, we demonstrate that a peptide derived from β-neurexin is a powerful competitive inhibitor capable of efficiently blocking surface attachment, homophilic adhesion, and biofilm accumulation. Molecular modeling suggests that this blocking activity may originate from binding of the peptide to a sequence of SdrC involved in homophilic interactions. Our study opens up avenues for understanding the role of homophilic interactions in staphylococcal adhesion, and for the design of new molecules to prevent biofilm formation during infection.}, } @article {pmid28320039, year = {2017}, author = {Valizadeh, N and Valian, F and Sadeghifard, N and Karami, S and Pakzad, I and Kazemian, H and Ghafourian, S}, title = {The Role of Peganum harmala Ethanolic Extract and Type II Toxin Antitoxin System in Biofilm Formation.}, journal = {Drug research}, volume = {67}, number = {7}, pages = {385-387}, doi = {10.1055/s-0043-102060}, pmid = {28320039}, issn = {2194-9387}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Cells, Cultured ; Ethanol/*chemistry ; Humans ; Klebsiella pneumoniae/*metabolism ; Peganum/*chemistry ; Plant Extracts/chemistry/*pharmacology ; *Toxin-Antitoxin Systems ; }, abstract = {Toxin antitoxin system is a regulatory system that antitoxin inhibits the toxin. We aimed to determine the role of TA loci in biofilm formation in K. pneumoniae clinical and environmental isolates; also inhibition of biofilm formation by Peganum harmala. So, 40 K. pneumoniae clinical and environmental isolates were subjected for PCR to determine the frequency of mazEF, relEB, and mqsRA TA loci. Biofilm formation assay subjected for all isolates. Then, P. harmala was tested against positive biofilm formation strains. Our results demonstrated that relBE TA loci were dominant TA loci; whereas mqsRA TA loci were negative in all isolates. The most environmental isolates showed weak and no biofilm formation while strong and moderate biofilm formation observed in clinical isolates. Biofilm formations by K. pneumoniae in 9 ug/ml concentration were inhibited by P. harmala. In vivo study suggested to be performed to introduce Peganum harmala as anti-biofilm formation in K. pneumoniae.}, } @article {pmid28319869, year = {2017}, author = {Sai Saraswathi, V and Kamarudheen, N and Bhaskara Rao, KV and Santhakumar, K}, title = {Biofilm inhibition formation of clinical strains of Pseudomonas aeruginosa mutans, photocatalytic activity of azo dye and GC-MS analysis of leaves of Lagerstroemia speciosa.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {169}, number = {}, pages = {148-160}, doi = {10.1016/j.jphotobiol.2017.03.007}, pmid = {28319869}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/isolation & purification/pharmacology ; Azo Compounds/*chemistry ; Biofilms/*drug effects ; Gas Chromatography-Mass Spectrometry ; Lagerstroemia/*chemistry ; *Photochemical Processes ; Plant Extracts/isolation & purification/metabolism/*pharmacology ; Plant Leaves/chemistry ; Pseudomonas aeruginosa/*physiology ; }, abstract = {The investigation was conducted to analyse the bioactive compounds from the leaf extracts of L. speciosa by GC-MS. The extracts were screened for antibacterial and antibiofilm activities against potential clinical strains. The bioactive compounds from the leaves of L. speciosa were extracted by soxhlet continuous extraction method and their chemical composition was analysed by Gas Chromatography-Mass Spectroscopy (GC-MS). The antibacterial activity was evaluated against clinical strain like Staphylococcus aureus, Escherichia coli, P. aeruginosa and Salmonella typhi by well diffusion technique. We also screened for antibacterial property against common food borne pathogens namely Listeria monocytogenes and Bacillus cereus at varied concentration 250μml[-1] to 1000μml[-1]. Thereafter antibiofilm assay was carried out at from 250 to 1000μg/ml against P. aeruginosa (high biofilm forming pathogen) clinical strain by cover slip technique and the morphology of the pathogen was observed using Scanning Electron Microscopy-(SEM). It was observed that diverse class of secondary metabolites were found by GC-MS analysis for all the extracts upon the continuous extraction. It was found that only minimum inhibition was seen in alcoholic extract for antibacterial activity, whereas all other extracts showed negligible activity. P. aeruginosa biofilm inhibited to 93.0±2% and 91±2% at higher concentration (1000μg/ml) for methanolic and ethanolic extract respectively. Absence of extracellular matrix structure and the surface cracking of biofilm were viewed by SEM, which confirmed the antibiofilm activity. Hence this study reveals that L. speciosa showed significant antibiofilm activity against P. aeruginosa due to the phytoconstituents present in the leaf extracts which was well documented in the alcoholic extracts by GC-MS analysis. The methanolic and ethanolic extract showed good photocatalytic activity of 77.44% and 96.66% against azo dye degradation respectively. Further, isolating the novel phyto-compounds would yield better promising biological activities.}, } @article {pmid28319414, year = {2017}, author = {Barad, S and Roudbary, M and Omran, AN and Daryasari, MP}, title = {Preparation and characterization of ZnO nanoparticles coated by chitosan-linoleic acid; fungal growth and biofilm assay.}, journal = {Bratislavske lekarske listy}, volume = {118}, number = {3}, pages = {169-174}, doi = {10.4149/BLL_2017_034}, pmid = {28319414}, issn = {0006-9248}, mesh = {Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/ultrastructure ; Chitosan/*pharmacology ; Fluconazole/pharmacology ; Linoleic Acid/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Nanoparticles/ultrastructure ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction ; Zinc Oxide/*pharmacology ; }, abstract = {INTRODUCTION: This study has been carried out on reviewing the use of new synthetic component of zinc oxide nanoparticles (ZnO NPs) coated by Chitosan-linoleic acid (CS-LA) and to assess Minimum inhibitory concentration (MIC) of nanoparticles on clinical samples and biofilm formation in vitro.

MATERIALS AND METHODS: At first the synthesized ZnO NPs coated by CS-LA were identified with X-ray powder diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Fourier Transform Infrared Spectroscopy analysis (FTIR).Through in vitro tests, the value of MIC and Minimum fungicide concentration (MFC) of nanoparticles and standard and clinical strains of candida were evaluated in comparison with fluconazole as the control group using the CLSI-M27 method. Finally, biofilm formation was studied using MTT assay.

RESULT: The results showed that MIC50 of fluconazole and nanoparticle in clinical strains was 64 µg/ml and 128 µg/ml, respectively. The MIC of fluconazole and nanoparticle in C. albicans (ATCC10231) was 8 µg/ml and 32 µg/ml respectively. The MFC of nanoparticle and fluconazole for clinical samples was recorded at similar level (128 μg/ml). MTT results indicated that the capacity of inhibition of biofilm formation was 43.07 % and 36.68 % by ZnO NPs and fluconazole, respectively.

CONCLUSION: It is concluded that the new synthesized nanoparticle has appropriate efficacy compared with fluconazole in inhibitory activity on C. albicans growth and biofilm formation. As a result, ZnO NPs can be introduced as an effective agent for diminishing adhesion capacity of C. albicans (Tab. 1, Fig. 4, Ref. 26).}, } @article {pmid28319101, year = {2017}, author = {Papenfort, K and Silpe, JE and Schramma, KR and Cong, JP and Seyedsayamdost, MR and Bassler, BL}, title = {A Vibrio cholerae autoinducer-receptor pair that controls biofilm formation.}, journal = {Nature chemical biology}, volume = {13}, number = {5}, pages = {551-557}, pmid = {28319101}, issn = {1552-4469}, support = {/HHMI/Howard Hughes Medical Institute/United States ; R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Pyrazoles/chemistry/*metabolism ; Quorum Sensing ; Repressor Proteins/chemistry/genetics/*metabolism ; Vibrio cholerae/genetics/growth & development/*metabolism ; }, abstract = {Quorum sensing (QS) is a cell-cell communication process that enables bacteria to track cell population density and orchestrate collective behaviors. QS relies on the production and detection of, and the response to, extracellular signal molecules called autoinducers. In Vibrio cholerae, multiple QS circuits control pathogenesis and biofilm formation. Here, we identify and characterize a new QS autoinducer-receptor pair. The autoinducer is 3,5-dimethylpyrazin-2-ol (DPO). DPO is made from threonine and alanine, and its synthesis depends on threonine dehydrogenase (Tdh). DPO binds to and activates a transcription factor, VqmA. The VqmA-DPO complex activates expression of vqmR, which encodes a small regulatory RNA. VqmR represses genes required for biofilm formation and toxin production. We propose that DPO allows V. cholerae to regulate collective behaviors to, among other possible roles, diversify its QS output during colonization of the human host.}, } @article {pmid28318295, year = {2017}, author = {Sukačová, K and Kočí, R and Žídková, M and Vítěz, T and Trtílek, M}, title = {Novel insight into the process of nutrients removal using an algal biofilm: The evaluation of mechanism and efficiency.}, journal = {International journal of phytoremediation}, volume = {19}, number = {10}, pages = {909-914}, doi = {10.1080/15226514.2017.1303810}, pmid = {28318295}, issn = {1549-7879}, mesh = {Biodegradation, Environmental ; *Biofilms ; *Nitrogen ; *Phosphorus ; Waste Disposal, Fluid ; *Water Purification ; }, abstract = {Eutrophication of water by nutrient pollution remains an important environmental issue. The aim of this study was to evaluate the nutrient uptake capacity of an algal biofilm as a means to treat polluted water. In addition, the study investigated the nutrient removal process. The algal biofilm was able to remove 99% of phosphorus within 24 hours of P addition, with the PO4-P concentration in inflowing water ranging from 3 to 10 mg L[-1]. Different patterns of phosphorus and nitrogen removal were observed. Daily quantity of removed NO3-N ranged from 2 to 25% and was highly dependent on solar irradiance. Precipitation of phosphorus during the removal process was studied using X-ray diffraction analyses and was not confirmed in the biofilm. The biofilm system we constructed has a high efficiency for phosphorus removal and, therefore, has great potential for integration into wastewater treatment processes.}, } @article {pmid28303823, year = {2017}, author = {Kackar, S and Suman, E and Kotian, MS}, title = {Bacterial and fungal biofilm formation on contact lenses and their susceptibility to lens care solutions.}, journal = {Indian journal of medical microbiology}, volume = {35}, number = {1}, pages = {80-84}, doi = {10.4103/ijmm.IJMM_16_273}, pmid = {28303823}, issn = {1998-3646}, mesh = {Anti-Infective Agents/*pharmacology ; Bacteria/*drug effects/virology ; Bacteriolysis ; Biofilms/*growth & development ; Candida albicans/*drug effects/physiology ; Coliphages/growth & development ; Colony Count, Microbial ; Contact Lens Solutions/*pharmacology ; Contact Lenses/*microbiology ; Microscopy, Electron, Scanning ; Spectrophotometry ; }, abstract = {BACKGROUND: Microbial biofilm formation on contact lenses and lens storage cases may be a risk factor for contact lens-associated corneal infections. Various types of contact lens care solutions are used to reduce microbial growths on lenses.

OBJECTIVES: The present study aimed at comparing the growths of biofilms on the different contact lenses and lens cases. The study also aimed at determining the effect of lens care solutions and bacteriophage on these biofilms.

MATERIALS AND METHODS: One type of hard lens and two types of soft lenses were used for the study. The organisms used were Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 60193 and Escherichia coli ATCC 25922. Biofilm production was performed by modified O'Toole and Kolter method and effect of lens cleaning solutions and a crude coliphage on biofilms was also studied. Results were visualised using scanning electron microscopy and quantitated by colony counting method and spectrophotometric measurement of optical density (OD). Statistical analysis was done by SPSS 11.5, Kruskal-Wallis test and Chi-square test.

RESULTS: Soft lens cleaning solutions had a significant inhibitory effect (P = 0.020) on biofilm formation on soft lenses and also lens cases (P < 0.001). Soft lens cleaning solution 2 was more efficient than solution 1. However, no such inhibitory effect was observed with regard to hard lens cleaning solution, but for a significant reduction in the OD values (P < 0.001). There was no significant inhibitory effect by bacteriophages.

CONCLUSION: This study showed the importance of selecting the appropriate lens cleaning solution to prevent biofilm production on contact lenses.}, } @article {pmid28303818, year = {2017}, author = {Garg, S and Mohan, B and Taneja, N}, title = {Biofilm formation capability of enterococcal strains causing urinary tract infection vis-a-vis colonisation and correlation with enterococcal surface protein gene.}, journal = {Indian journal of medical microbiology}, volume = {35}, number = {1}, pages = {48-52}, doi = {10.4103/ijmm.IJMM_16_102}, pmid = {28303818}, issn = {1998-3646}, mesh = {Bacterial Proteins ; Biofilms/*growth & development ; Carrier State/*microbiology ; Enterococcus/*genetics/isolation & purification/*physiology ; Gram-Positive Bacterial Infections/*microbiology ; Humans ; Membrane Proteins/*genetics ; Polymerase Chain Reaction ; Prospective Studies ; Urinary Tract Infections/*microbiology ; }, abstract = {BACKGROUND: Data regarding differences in biofilm formation among urinary isolates of enterococci causing nosocomial infection versus asymptomatic colonisation is lacking. Conflicting data are available for the role of enterococcal surface protein (esp) gene in the development of enterococcal biofilms.

MATERIALS AND METHODS: A total of 50 (25 each of asymptomatic bacteriuria and urinary tract infection (UTI) isolates were collected from admitted patients who had nosocomial acquisition of enterococci in urine culture (≥105 cfu/ml). Biofilm assay was done by the quantitative adherence assay. Screening for esp gene was carried out by polymerase chain reaction, and confocal laser scanning microscopy was used to examine biofilms.

RESULTS: Out of 25 enterococcal isolates from asymptomatic patients, 9 (36%) isolates were found to be biofilm producers (6 weak [optical densities [OD]595 0.2] and three medium [OD595≥0.2 to595>0.5]). The esp gene was present in 30 (12 biofilm+, 18 biofilm-) isolates. Seventeen esp positive isolates were from asymptomatic cases whereas 13 were from UTI. However, we found that 100% of medium and strong biofilm producers were esp positive (P < 0.001). On comparing Enterococcus faecalis (n = 10) and E. faecium (n = 40) isolates, 70% of E. faecalis isolates were biofilm producers as compared to only 35% of E. faecium isolates (P > 0.05). The esp positivity was observed more in E. faecium isolates (65%) as compared to 40% in E. faecalis. Vancomycin-sensitive enterococcal and vancomycin-resistant enterococcal isolates and catheter-related and unrelated isolates showed similarity in biofilm production and esp positivity.

CONCLUSION: The esp gene is not compulsorily required to produce biofilm but when present may enhance the biofilm formation. We did not find any correlation between biofilm formation and the ability of the strain to cause symptomatic UTI be associated with catheters or vancomycin resistance.}, } @article {pmid28303583, year = {2017}, author = {Matthes, R and Duske, K and Kebede, TG and Pink, C and Schlüter, R and von Woedtke, T and Weltmann, KD and Kocher, T and Jablonowski, L}, title = {Osteoblast growth, after cleaning of biofilm-covered titanium discs with air-polishing and cold plasma.}, journal = {Journal of clinical periodontology}, volume = {44}, number = {6}, pages = {672-680}, doi = {10.1111/jcpe.12720}, pmid = {28303583}, issn = {1600-051X}, mesh = {Air Abrasion, Dental/*methods ; Bacteria/drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Cell Line ; Cells, Cultured ; Dental Implants ; Dental Plaque ; Hydrophobic and Hydrophilic Interactions ; Materials Testing ; Microscopy, Electron, Scanning ; *Osteoblasts/cytology/drug effects ; Peri-Implantitis/microbiology/therapy ; Plasma Gases/chemistry/*pharmacology ; Powders ; Surface Properties ; Titanium/*chemistry ; }, abstract = {AIM: To investigate the effects of a combined biofilm removal with an optimized air polishing and a cold plasma device on cells in vitro.

MATERIALS AND METHODS: A 7-day-old biofilm was removed from rough titanium discs with an air-polishing device with erythritol powder (AP) or with a cold atmospheric pressure argon plasma (CAP) device or in combination of both (AP + CAP). The removal efficacy was evaluated by subsequent cell seeding of osteoblast-like cells (MG-63). The cell spreading was analysed after 5 days of incubation by scanning electron microscopy. Separately, the surface hydrophilicity was analysed by measuring the water contact angle (WCA) of the disc for each treatment method.

RESULTS: The mechanical plaque removal with AP rendered specimen conducive for cell growth, 85% of the surface was covered with cells. An advantage of the combination of AP + CAP was not detectable compared to AP (cell coverage ranged from 57% up to 75%). After sole CAP treatment, microorganisms re-grew and destroyed all cells. The WCA was reduced by all treatment methods.

CONCLUSION: An AP treatment has the potential to remove biofilm from rough implant surfaces completely. In contrast to our hypothesis, the combination of plasma and AP treatment did not enhance osteoblast spreading.}, } @article {pmid28301918, year = {2017}, author = {Lee, K and Yoon, SS}, title = {Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.}, journal = {Journal of microbiology and biotechnology}, volume = {27}, number = {6}, pages = {1053-1064}, doi = {10.4014/jmb.1611.11056}, pmid = {28301918}, issn = {1738-8872}, mesh = {Biofilms/*growth & development ; Coinfection ; Cystic Fibrosis/microbiology ; Genetic Fitness ; Humans ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/growth & development/*physiology ; Quorum Sensing ; }, abstract = {A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. Pseudomonas aeruginosa is a bacterium known to produce robust biofilms. P. aeruginosa biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of P. aeruginosa biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species (i.e., multispecies biofilms) are discussed in detail.}, } @article {pmid28301290, year = {2017}, author = {Acosta-Rubí, S and Campocosio, AT and Montes-Horcasitas, MDC and Quintanar-Vera, L and Esparza-García, F and Rodríguez-Vázquez, R}, title = {Production of a halotolerant biofilm from green coffee beans immobilized on loofah fiber (Luffa cylindrica) and its effect on phenanthrene degradation in seawater.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {52}, number = {7}, pages = {632-640}, doi = {10.1080/10934529.2017.1294965}, pmid = {28301290}, issn = {1532-4117}, mesh = {Biodegradation, Environmental ; Biofilms/*growth & development ; Coffee/*chemistry ; Industrial Waste/analysis ; Luffa/*chemistry ; Microbial Consortia ; Phenanthrenes/*analysis ; Salinity ; Seawater/*chemistry ; Surface Properties ; Water Pollutants, Chemical/*analysis ; }, abstract = {A biofilm developed from low quality green coffee beans was tested for its capacity to degrade the polynuclear aromatic hydrocarbon (PAH), phenanthrene (Phe), in seawater. Microorganisms were immobilized on two types of Luffa cylindrica (with three and four placental cavities), and the effects of moisture content (20, 30 and 40% of water holding capacity) and particle size (<0.42 mm, 0.42-0.86 mm and 0.86-2.0 mm) of green coffee beans on microbial activity were considered. Biofilm growth determined by respirometry showed a highest microbial activity at a moisture content of 40% and particle size of 0.42-0.86 mm. The loofah fiber with three placental cavities showed the highest adherence of microorganisms. The kinetics of microbial growth in both seawater and distilled water and the scanning electron microscopies indicated that the microorganisms associated with green coffee beans are halotolerant. In fact, I-GCB-SW-G biofilm degraded 67.56% of Phe (50 mg L[-1]) in seawater, at a significantly higher rate than in distilled water (I-GCB-DW-W).}, } @article {pmid28298975, year = {2017}, author = {Yadav, P and Chaudhary, S and Saxena, RK and Talwar, S and Yadav, S}, title = {Evaluation of Antimicrobial and Antifungal efficacy of Chitosan as endodontic irrigant against Enterococcus Faecalis and Candida Albicans Biofilm formed on tooth substrate.}, journal = {Journal of clinical and experimental dentistry}, volume = {9}, number = {3}, pages = {e361-e367}, pmid = {28298975}, issn = {1989-5488}, abstract = {BACKGROUND: Bacterial biofilms formed on the root canal wall are often difficult to remove. This study aimed to evaluate the cytotoxic effect and antibacterial efficacy of chitosan when used as root canal irrigant against E. Faecalis and Candida albicans biofilm formed on tooth substrate.

MATERIAL AND METHODS: The present study evaluated antibacterial effect of 0.25% Chitosan, 0.5% Chitosan, 2% chlorhexidine and 3% sodium hypochlorite against Enterococcus faecalis and Candida Albicans. Agar-well diffusion methods, minimal inhibitory concentration tests and biofilm susceptibility assays were used to determine antibacterial activity. Teeth specimens were sectioned to obtain a standardized tooth length of 12mm. Specimens were inoculated with 10 mL of the freshly prepared E. Faecalis suspension and Candida albicans for 4 weeks. The specimens were then instrumented with ProTaper rotary files F3 size. After irrigation with test solution, three sterile paper points were placed into one canal, left for 60 s and transferred to a test tube containing 1 mL of reduced transport fluid. The number of CFU in 1 mL was determined.

RESULTS: 3-week biofilm qualitative assay showed complete inhibition of bacterial growth with 3% Sodium hypochlorite, 2% Chlorhexidine and Chitosan except saline, which showed presence of bacterial growth. Significant reduction of colony forming units (CFU)/mL was observed for the chitosan groups and the antibacterial activity of the chitosan groups was at par with 3% NaOCl and 2% Chlorhexidine. It was observed that the chitosan showed no cytotoxicity at 3mg/ml and 10% cytotoxicity at 6mg/ml.

CONCLUSIONS: The use of chitosan as a root canal irrigant might be an alternative considering the various undesirable properties of NaOCl and chlorhexidine. Key words:Biofilm, Candida albicans, Chitosan, Cytotoxicity, Enterococcus faecalis.}, } @article {pmid28297746, year = {2017}, author = {Wang, J and Nong, XH and Zhang, XY and Xu, XY and Amin, M and Qi, SH}, title = {Screening of Anti-Biofilm Compounds from Marine-Derived Fungi and the Effects of Secalonic Acid D on Staphylococcus aureus Biofilm.}, journal = {Journal of microbiology and biotechnology}, volume = {27}, number = {6}, pages = {1078-1089}, doi = {10.4014/jmb.1609.09053}, pmid = {28297746}, issn = {1738-8872}, mesh = {Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Aquatic Organisms/chemistry ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Biological Products/chemistry/isolation & purification/pharmacology ; Citrinin/chemistry/pharmacology ; Fungi/*chemistry ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/genetics/physiology ; Xanthones/*pharmacology ; }, abstract = {Biofilm formation of Staphylococcus aureus is one of its mechanisms of drug resistance. Antibiofilm screening of 106 compounds from marine-derived fungi displayed that 12 compounds inhibited S. aureus biofilm formation by >50% at the concentration of 100 μg/ml, and only secalonic acid D (SAD) and B inhibited by >90% at 6.25 μg/ml without inhibiting cell growth after 24-h incubation. Meanwhile, it was found that the double bond between C-1 and C-10 of citrinin derivatives and the C-C connection position of two chromone monomers may be important for their anti-biofilm activities. Moreover, SAD slightly facilitated biofilm eradication and influenced its architecture. Furthermore, SAD slowed the cell growth rate in the preceding 18-h incubation and differentially regulated transcriptional expression of several genes, such as agr, isaA, icaA, and icaD, associated with biofilm formation in planktonic and biofilm cells, which may be the reason for the anti-biofilm activity of SAD. Finally, SAD acted synergistically against S. aureus growth and biofilm formation with other antibiotics. These findings indicated that various natural products from marine-derived fungi, such as SAD, could be used as a potential biofilm inhibitor against S. aureus.}, } @article {pmid28296966, year = {2017}, author = {Kommerein, N and Stumpp, SN and Müsken, M and Ehlert, N and Winkel, A and Häussler, S and Behrens, P and Buettner, FF and Stiesch, M}, title = {An oral multispecies biofilm model for high content screening applications.}, journal = {PloS one}, volume = {12}, number = {3}, pages = {e0173973}, pmid = {28296966}, issn = {1932-6203}, mesh = {Bacteria/classification/*metabolism ; *Biofilms ; In Situ Hybridization, Fluorescence ; Microscopy, Electron, Scanning ; Mouth/*microbiology ; Species Specificity ; }, abstract = {Peri-implantitis caused by multispecies biofilms is a major complication in dental implant treatment. The bacterial infection surrounding dental implants can lead to bone loss and, in turn, to implant failure. A promising strategy to prevent these common complications is the development of implant surfaces that inhibit biofilm development. A reproducible and easy-to-use biofilm model as a test system for large scale screening of new implant surfaces with putative antibacterial potency is therefore of major importance. In the present study, we developed a highly reproducible in vitro four-species biofilm model consisting of the highly relevant oral bacterial species Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis. The application of live/dead staining, quantitative real time PCR (qRT-PCR), scanning electron microscopy (SEM) and urea-NaCl fluorescence in situ hybridization (urea-NaCl-FISH) revealed that the four-species biofilm community is robust in terms of biovolume, live/dead distribution and individual species distribution over time. The biofilm community is dominated by S. oralis, followed by V. dispar, A. naeslundii and P. gingivalis. The percentage distribution in this model closely reflects the situation in early native plaques and is therefore well suited as an in vitro model test system. Furthermore, despite its nearly native composition, the multispecies model does not depend on nutrient additives, such as native human saliva or serum, and is an inexpensive, easy to handle and highly reproducible alternative to the available model systems. The 96-well plate format enables high content screening for optimized implant surfaces impeding biofilm formation or the testing of multiple antimicrobial treatment strategies to fight multispecies biofilm infections, both exemplary proven in the manuscript.}, } @article {pmid28294685, year = {2017}, author = {Rahman, MR and Lou, Z and Zhang, J and Yu, F and Timilsena, YP and Zhang, C and Zhang, Y and Bakry, AM}, title = {Star Anise (Illicium verum Hook. f.) as Quorum Sensing and Biofilm Formation Inhibitor on Foodborne Bacteria: Study in Milk.}, journal = {Journal of food protection}, volume = {80}, number = {4}, pages = {645-653}, doi = {10.4315/0362-028X.JFP-16-294}, pmid = {28294685}, issn = {1944-9097}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects ; Biofilms ; Humans ; *Illicium ; Milk/microbiology ; Pseudomonas aeruginosa ; *Quorum Sensing ; Staphylococcus aureus/drug effects ; }, abstract = {Bacteria use quorum sensing (QS) systems to communicate with each other and regulate microbial group behavior, such as the secretion of virulence factors, including biofilm formation. In order to explore safe, edible agents, the potential of star anise (SA) as an anti-QS and antibiofilm agent and its possible application in milk safety were investigated. Staphylococcus aureus , Salmonella Typhimurium, Pseudomonas aeruginosa , and biosensor strain Chromobacterium violaceum were selected as test strains for QS, biofilm, and exopolysaccharide assays. The percent acidities and total plate counts were determined to evaluate the quality of biofilm-inoculated and noninoculated milk. The yield of SA extraction was 25.90% ± 0.2% (w/w). At sub-MIC, SA extract did not show any effect on bacterial growth. The production of violacein was inhibited by 89% by SA extract. The extract also inhibited the formation of biofilm by up to 87% in a dose-dependent manner. Inhibition rates of 70.45%, 42.82%, and 35.66% were found for exopolysaccharide production. The swarming motility of S. aureus was reduced by about 95.9% by SA extract. Confocal laser scanning microscopy analysis confirmed that the development of biofilm architecture was hampered. It was found that SA extract could delay the spoilage of milk. In the endeavor to avoid drug resistance, pathogenesis, and resistance to biocides while improving food safety and avoiding health hazard issues arising from synthetic chemicals, SA extract could be used as a potential QS and biofilm inhibitor.}, } @article {pmid28293865, year = {2018}, author = {Shokri, D and Khorasgani, MR and Mohkam, M and Fatemi, SM and Ghasemi, Y and Taheri-Kafrani, A}, title = {The Inhibition Effect of Lactobacilli Against Growth and Biofilm Formation of Pseudomonas aeruginosa.}, journal = {Probiotics and antimicrobial proteins}, volume = {10}, number = {1}, pages = {34-42}, pmid = {28293865}, issn = {1867-1314}, support = {-//University of Isfahan/International ; 92045033//Iran National Science Foundation, Presidency of Islamic Republic of Iran Vice-Presidency for Science and Technology/International ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Antibiosis ; Bacteriocins/biosynthesis ; *Biofilms/drug effects ; Drug Resistance, Multiple, Bacterial ; Lactobacillus/genetics/*physiology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/growth & development/*physiology ; }, abstract = {The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to identify safe and natural alternative agents of antibiotics such as probiotics. The aim of this study was the isolation of lactobacilli as potential probiotics from local dairy products with broad antibacterial and anti-biofilm activities against antibiotic-resistant strains of Pseudomonas aeruginosa and determination of their inhibition mechanism. Antibiotic susceptibility and classification of acquired resistance profiles of 80 P. aeruginosa strains were determined based on Centers for Disease Control and Prevention (CDC) new definition as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) followed by antibacterial assessment of lactobacilli against them by different methods. Among the 80 P. aeruginosa strains, 1 (1.3%), 50 (62.5%), and 78 (97.5%) were PDR, XDR, and MDR, respectively, and effective antibiotics against them were fosfomycin and polymyxins. Among 57 isolated lactobacillus strains, two strains which were identified as Lactobacillus fermentum using biochemical and 16S rDNA methods showed broad inhibition/killing and anti-biofilm effects against all P. aeruginosa strains. They formed strong biofilms and had bile salts and low pH tolerance. Although investigation of inhibition mechanism of these strains showed no bacteriocin production, results obtained by high-performance liquid chromatography (HPLC) analysis indicated that their inhibitory effect was the result of production of three main organic acids including lactic acid, acetic acid, and formic acid. Considering the broad activity of these two L. fermentum strains, they can potentially be used in bio-control of drug-resistant strains of P. aeruginosa.}, } @article {pmid28291433, year = {2017}, author = {Göçer, H and Emir, D and Önger, ME and Dabak, N}, title = {Effects of bone cement loaded with teicoplanin, N-acetylcysteine or their combination on Staphylococcus aureus biofilm formation: an in vitro study.}, journal = {Eklem hastaliklari ve cerrahisi = Joint diseases & related surgery}, volume = {28}, number = {1}, pages = {13-18}, doi = {10.5606/ehc.2017.52507}, pmid = {28291433}, issn = {1309-0313}, mesh = {Acetylcysteine/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Load ; Biofilms/*drug effects ; Bone Cements ; Expectorants/*pharmacology ; Staphylococcus aureus/*drug effects ; Teicoplanin/*pharmacology ; }, abstract = {OBJECTIVES: This study aims to demonstrate the antibiofilm effects of teicoplanin alone, N-acetyl cysteine (NAC) alone, or combination of both compounds when mixed with bone cement.

MATERIALS AND METHODS: A total of four groups were formed by using six cement samples in each, prepared with bone cement having different contents in each group. Group 1 (control group): cement alone without any drugs added. Group 2: 40 g cement, 400 mg teicoplanin. Group 3: 40 g cement, 6 g NAC. Group 4: 40 g cement, 6 g NAC, 400 mg teicoplanin. All cement samples were infected with Staphylococcus aureus for 48 hours at 36.5 °C. Bacterial colonies were then counted by serial dilution method. Bacteria were counted using scanning electron microscopic (SEM) images.

RESULTS: Counts of bacteria colonies were 5.83±1.60 [mean colony forming unit (cfu) x 105±standard deviation (SD)] in group 1, 0.12±0.56 in group 2, 0.11±0.65 in group 3, and 0.01±0.001 in group 4. Significant difference was found between group 1 and all other groups (p<0.05), and between group 4 and all other groups (p<0.05). According to SEM analysis, counts of bacteria (mean±SD) were 1.88±0.45, 0.75±0.26, 0.21±0.22, and 0.13±0.25 in groups 1, 2, 3, and 4, respectively. Significant difference was found between group 1 and all other groups (p<0.05), and between group 4 and all other groups (p<0.05).

CONCLUSION: N-acetyl cysteine, teicoplanin, and their combination significantly reduced formation of biofilm compared to the control group. Also, combination of NAC and teicoplanin had the highest antibiofilm effect.}, } @article {pmid28291188, year = {2017}, author = {Carli, AV and Bhimani, S and Yang, X and Shirley, MB and de Mesy Bentley, KL and Ross, FP and Bostrom, MP}, title = {Quantification of Peri-Implant Bacterial Load and in Vivo Biofilm Formation in an Innovative, Clinically Representative Mouse Model of Periprosthetic Joint Infection.}, journal = {The Journal of bone and joint surgery. American volume}, volume = {99}, number = {6}, pages = {e25}, doi = {10.2106/JBJS.16.00815}, pmid = {28291188}, issn = {1535-1386}, mesh = {Animals ; Bacterial Load ; *Biofilms ; Disease Models, Animal ; Knee Joint/diagnostic imaging/*microbiology ; Mice ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/diagnostic imaging/*microbiology ; Radiography ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*isolation & purification ; }, abstract = {BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty. Current animal models of PJI are limited because of a lack of quantitative methods and failure to effectively recreate the periprosthetic space. We therefore developed a murine PJI model involving a 3-dimensionally printed Ti-6Al-4V implant capable of bearing weight and permitting quantitative analysis of periprosthetic bacterial load and evaluation of biofilm.

METHODS: Twenty-five 12-week-old C57BL/6 mice received a unilateral proximal tibial implant and intra-articular injection of either 3 × 10 colony forming units (CFUs) of Staphylococcus aureus Xen 36 or saline solution. Postoperatively, mice underwent gait analysis, knee radiographs, and serum inflammatory marker measurements. Following euthanasia at 2 or 6 weeks, bone and soft tissues were homogenized to quantify bacteria within periprosthetic tissues. Implants were either sonicated to quantify adherent bacteria or examined under scanning electron microscopy (SEM) to characterize biofilm.

RESULTS: All mice survived surgery and were not systemically septic. The control mice immediately tolerated weight-bearing and had normal inflammatory markers and radiographic signs of osseointegration. Infected mice had difficulty walking over time, exhibited radiographic findings of septic implant loosening, and had significantly elevated inflammatory markers. Periprosthetic tissues of the infected animals displayed a mean of 4.46 × 10 CFUs of S. aureus at 2 weeks and 2.53 × 10 CFUs at 6 weeks. Viable S. aureus was quantified on retrieved implant surfaces. SEM demonstrated S. aureus cocci in clusters encased within biofilm.

CONCLUSIONS: This animal model is, to our knowledge, the most clinically representative PJI replication to date. It is the first that we know of to produce infection through the same method hypothesized to occur clinically, utilize a weight-bearing implant that can osseointegrate, and provide quantitative data on 8 aspects of PJI, including radiographic features, inflammatory markers, and bacterial loads.

CLINICAL RELEVANCE: This novel animal model is, to our knowledge, the first to provide a load-bearing translational representation of clinical PJI that effectively recreates the periprosthetic space.}, } @article {pmid28290331, year = {2017}, author = {In Lee, SH and Barancelli, GV and de Camargo, TM and Corassin, CH and Rosim, RE and da Cruz, AG and Cappato, LP and de Oliveira, CA}, title = {Biofilm-producing ability of Listeria monocytogenes isolates from Brazilian cheese processing plants.}, journal = {Food research international (Ottawa, Ont.)}, volume = {91}, number = {}, pages = {88-91}, doi = {10.1016/j.foodres.2016.11.039}, pmid = {28290331}, issn = {1873-7145}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Brazil ; Cheese/*microbiology ; *Equipment Contamination ; Equipment Design ; *Food Contamination ; *Food Microbiology ; Food-Processing Industry/instrumentation/*methods ; Listeria monocytogenes/classification/*growth & development ; Polystyrenes/chemistry ; Salts/analysis ; Stainless Steel/chemistry ; Surface Properties ; }, abstract = {The persistence of Listeria monocytogenes in food industry environments has been associated to the ability of specific isolates to produce biofilms. This study aimed to evaluate the biofilm production of 85 L. monocytogenes strains previously isolated from samples of cheese, brine and the environment of two cheese processing plants located in São Paulo, Brazil. The L. monocytogenes isolates belonged to serotypes 4b, 1/2b and 1/2c, yielded 30 different pulsotypes by pulsed-field gel electrophoresis (PFGE), and were submitted to biofilm-formation assays on polystyrene microplates and stainless steel coupons incubated statically at 35±0.5°C for 48h. All isolates from different sources showed ability to produce biofilms on polystyrene microplates, from which 21 (24.7%) also produced biofilms on stainless steel. Four isolates (4.7%) belonging to four different pulsotypes were classified as strong biofilms-producers on polystyrene microplates, while isolates belonging to four pulsotypes previously evaluated as persistent had weak or moderate ability to produce biofilms on polystyrene microplates. No relationship between the serotypes or pulsotypes and their biofilm-forming ability was observed. This study highlights the high variability in the biofilm production among L. monocytogenes strains collected from cheese and cheese-production environment, also indicating that strong biofilm-formation ability is not a key factor for persistence of specific isolates in cheese processing plants.}, } @article {pmid28290008, year = {2017}, author = {Zhao, J and Wang, Q}, title = {Three-Dimensional Numerical Simulations of Biofilm Dynamics with Quorum Sensing in a Flow Cell.}, journal = {Bulletin of mathematical biology}, volume = {79}, number = {4}, pages = {884-919}, doi = {10.1007/s11538-017-0259-4}, pmid = {28290008}, issn = {1522-9602}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Biomass ; *Quorum Sensing ; }, abstract = {We develop a multiphasic hydrodynamic theory for biofilms taking into account interactions among various bacterial phenotypes, extracellular polymeric substance (EPS), quorum sensing (QS) molecules, solvent, and antibiotics. In the model, bacteria are classified into down-regulated QS, up-regulated QS, and non-QS cells based on their QS ability. The model is first benchmarked against an experiment yielding an excellent fit to experimental measurements on the concentration of QS molecules and the cell density during biofilm development. It is then applied to study development of heterogeneous structures in biofilms due to interactions of QS regulation, hydrodynamics, and antimicrobial treatment. Our 3D numerical simulations have confirmed that (i). QS is beneficial for biofilm development in a long run by building a robust EPS population to protect the biofilm; (ii). biofilms located upstream can induce QS downstream when the colonies are close enough spatially; (iii). QS induction may not be fully operational and can even be compromised in strong laminar flows; (v). the hydrodynamic stress alters the biofilm morphology. Through further numerical investigations, our model suggests that (i). QS-regulated EPS production contributes to the structural formation of heterogeneous biofilms; (ii) QS down-regulated cells tend to grow at the surface of the biofilm while QS up-regulated ones tend to grow in the bulk; (iii) when nutrient supply is sufficient, QS induction might be more effective upstream than downstream; (iv) QS may be of little benefit in a short timescale in term of fighting against invading strain/species; (v) the material properties of biomass (bacteria and EPS) have strong impact on the dilution of QS molecules under strong shear flow. In addition, with this modeling framework, hydrodynamic details and rheological quantities associated with biofilm formation under QS regulation can be resolved.}, } @article {pmid28289362, year = {2016}, author = {Ramakrishnan, M and Putli Bai, S and Babu, M}, title = {Study on biofilm formation in burn wound infection in a pediatric hospital in Chennai, India.}, journal = {Annals of burns and fire disasters}, volume = {29}, number = {4}, pages = {276-280}, pmid = {28289362}, issn = {1592-9558}, abstract = {Infection is one of the major causes of death in pediatric burns in India. This work was conducted in an exclusive Children's Hospital (KKCTH) with a total of 220 beds, of which ten beds in the burn unit and two isolation beds in the 28-bed PICU are for burns patients (more than 20% TBSA burns) with sepsis. In this study, 30 burn wound swab isolates obtained from 14 pediatric burns patients (admitted to the burns ward and transferred to PICU) from November 2013 to March 2014 were investigated. Cultures were done on the first day for all patients and empirical antibiotic administration was started for those with septic burns (14 in total) with piperacillin-tazobactam and vancomycin. Antibiotics were changed according to antibiotic sensitivity reports. Cultures were repeated for culture positive cases on the fifth day. Further antibiotic treatment was based on this culture report. When the general condition of the patient did not respond to highlevel antibiotics, biofilm formation was suspected and evaluated as the possible cause of antibiotic resistance. For these patients, an enhanced method of wound debridement and albumin transfusions were used to improve their general condition. Microbial identification and antimicrobial sensitivity testing was done for all 30 isolates. The predominant bacteria were Pseudomonas aeruginosa, Acinetobacter and Staphylococcus aureus. Most of the Acinetobacter and Staphylococcus aureus showed multidrug resistance. Biofilm formation was studied using the Tissue Culture Plate (TCP) method for all bacterial isolates, and results showed that most of the MDR isolates formed biofilm.}, } @article {pmid28289087, year = {2017}, author = {Luong, TT and Reardon-Robinson, ME and Siegel, SD and Ton-That, H}, title = {Reoxidation of the Thiol-Disulfide Oxidoreductase MdbA by a Bacterial Vitamin K Epoxide Reductase in the Biofilm-Forming Actinobacterium Actinomyces oris.}, journal = {Journal of bacteriology}, volume = {199}, number = {10}, pages = {}, pmid = {28289087}, issn = {1098-5530}, support = {R01 DE017382/DE/NIDCR NIH HHS/United States ; R01 DE025015/DE/NIDCR NIH HHS/United States ; }, mesh = {Actinomyces/*enzymology/genetics/*metabolism/physiology ; Alanine/genetics/metabolism ; Amino Acid Substitution ; Biofilms/*growth & development ; Cysteine/genetics/metabolism ; DNA Mutational Analysis ; Fimbriae, Bacterial/metabolism ; Microscopy, Electron, Transmission ; Models, Biological ; Models, Molecular ; Mutagenesis, Site-Directed ; Mutant Proteins/genetics/metabolism ; Mycobacterium tuberculosis/enzymology/genetics/metabolism ; Organelle Biogenesis ; Oxidation-Reduction ; Protein Disulfide Reductase (Glutathione)/*metabolism ; Vitamin K Epoxide Reductases/genetics/*metabolism ; }, abstract = {Posttranslocational protein folding in the Gram-positive biofilm-forming actinobacterium Actinomyces oris is mediated by a membrane-bound thiol-disulfide oxidoreductase named MdbA, which catalyzes oxidative folding of nascent polypeptides transported by the Sec translocon. Reoxidation of MdbA involves a bacterial vitamin K epoxide reductase (VKOR)-like protein that contains four cysteine residues, C93/C101 and C175/C178, with the latter forming a canonical CXXC thioredoxin-like motif; however, the mechanism of VKOR-mediated reoxidation of MdbA is not known. We present here a topological view of the A. oris membrane-spanning protein VKOR with these four exoplasmic cysteine residues that participate in MdbA reoxidation. Like deletion of the VKOR gene, alanine replacement of individual cysteine residues abrogated polymicrobial interactions and biofilm formation, concomitant with the failure to form adhesive pili on the bacterial surface. Intriguingly, the mutation of the cysteine at position 101 to alanine (C101A mutation) resulted in a high-molecular-weight complex that was positive for MdbA and VKOR by immunoblotting and was absent in other alanine substitution mutants and the C93A C101A double mutation and after treatment with the reducing agent β-mercaptoethanol. Consistent with this observation, affinity purification followed by immunoblotting confirmed this MdbA-VKOR complex in the C101A mutant. Furthermore, ectopic expression of the Mycobacterium tuberculosis VKOR analog in the A. oris VKOR deletion (ΔVKOR) mutant rescued its defects, in contrast to the expression of M. tuberculosis VKOR variants known to be nonfunctional in the disulfide relay that mediates reoxidation of the disulfide bond-forming catalyst DsbA in Escherichia coli Altogether, the results support a model of a disulfide relay, from its start with the pair C93/C101 to the C175-X-X-C178 motif, that is required for MdbA reoxidation and appears to be conserved in members of the class ActinobacteriaIMPORTANCE It has recently been shown in the high-GC Gram-positive bacteria (or Actinobacteria) Actinomyces oris and Corynebacterium diphtheriae that oxidative folding of nascent polypeptides transported by the Sec machinery is catalyzed by a membrane-anchored oxidoreductase named MdbA. In A. oris, reoxidation of MdbA requires a bacterial VKOR-like protein, and yet, how VKOR mediates MdbA reoxidation is unknown. We show here that the A. oris membrane-spanning protein VKOR employs two pairs of exoplasmic cysteine residues, including the canonical CXXC thioredoxinlike motif, to oxidize MdbA via a disulfide relay mechanism. This mechanism of disulfide relay is essential for pilus assembly, polymicrobial interactions, and biofilm formation and appears to be conserved in members of the class Actinobacteria, including Mycobacterium tuberculosis.}, } @article {pmid28289031, year = {2017}, author = {Fernández, L and González, S and Campelo, AB and Martínez, B and Rodríguez, A and García, P}, title = {Downregulation of Autolysin-Encoding Genes by Phage-Derived Lytic Proteins Inhibits Biofilm Formation in Staphylococcus aureus.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {5}, pages = {}, pmid = {28289031}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Cell Wall/metabolism ; Endopeptidases/metabolism ; Lysostaphin/metabolism ; N-Acetylmuramoyl-L-alanine Amidase/*genetics ; Staphylococcus Phages/*genetics ; Staphylococcus aureus/drug effects/genetics/*metabolism/*virology ; Viral Fusion Proteins/genetics/*pharmacology ; }, abstract = {Phage-derived lytic proteins are a promising alternative to conventional antimicrobials. One of their most interesting properties is that they do not readily select for resistant strains, which is likely due to the fact that their targets are essential for the viability of the bacterial cell. Moreover, genetic engineering allows the design of new "tailor-made" proteins that may exhibit improved antibacterial properties. One example of this is the chimeric protein CHAPSH3b, which consists of a catalytic domain from the virion-associated peptidoglycan hydrolase of phage vB_SauS-phiIPLA88 (HydH5) and the cell wall binding domain of lysostaphin. CHAPSH3b had previously shown the ability to kill Staphylococcus aureus cells. Here, we demonstrate that this lytic protein also has potential for the control of biofilm-embedded S. aureus cells. Additionally, subinhibitory doses of CHAPSH3b can decrease biofilm formation by some S. aureus strains. Transcriptional analysis revealed that exposure of S. aureus cells to this enzyme leads to the downregulation of several genes coding for bacterial autolysins. One of these proteins, namely, the major autolysin AtlA, is known to participate in staphylococcal biofilm development. Interestingly, an atl mutant strain did not display inhibition of biofilm development when grown at subinhibitory concentrations of CHAPSH3b, contrary to the observations made for the parental and complemented strains. Also, deletion of atl led to low-level resistance to CHAPSH3b and the endolysin LysH5. Overall, our results reveal new aspects that should be considered when designing new phage-derived lytic proteins aimed for antimicrobial applications.}, } @article {pmid28289028, year = {2017}, author = {Lohse, MB and Gulati, M and Valle Arevalo, A and Fishburn, A and Johnson, AD and Nobile, CJ}, title = {Assessment and Optimizations of Candida albicans In Vitro Biofilm Assays.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {5}, pages = {}, pmid = {28289028}, issn = {1098-6596}, support = {R00 AI100896/AI/NIAID NIH HHS/United States ; R01 AI083311/AI/NIAID NIH HHS/United States ; R41 AI112038/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*growth & development ; Candida albicans/*drug effects/*pathogenicity ; Candidiasis/drug therapy/microbiology ; Caspofungin ; Cell Adhesion/*physiology ; Echinocandins/pharmacology ; Humans ; Lipopeptides/pharmacology ; Microbial Sensitivity Tests/methods ; Microfluidics/*methods ; Prosthesis-Related Infections/microbiology ; }, abstract = {Candida albicans biofilms have a significant medical impact due to their rapid growth on implanted medical devices, their resistance to antifungal drugs, and their ability to seed disseminated infections. Biofilm assays performed in vitro allow for rapid, high-throughput screening of gene deletion libraries or antifungal compounds and typically serve as precursors to in vivo studies. Here, we compile and discuss the protocols for several recently published C. albicansin vitro biofilm assays. We also describe improved versions of these protocols as well as novel in vitro assays. Finally, we consider some of the advantages and disadvantages of these different types of assays.}, } @article {pmid28288290, year = {2017}, author = {Clark, SA and Vinson, LA and Eckert, G and Gregory, RL}, title = {Effect of Commonly Prescribed Liquid Medications on Streptococcus mutans Biofilm. An in vitro study.}, journal = {The Journal of clinical pediatric dentistry}, volume = {41}, number = {2}, pages = {141-146}, doi = {10.17796/1053-4628-41.2.141}, pmid = {28288290}, issn = {1053-4628}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Streptococcus mutans/*drug effects ; }, abstract = {OBJECTIVE: This study addressed the effect of pediatric liquid antibiotic medications on Streptococcus mutans UA159. These suspensions commonly contain sugars such as sucrose to make them more palatable for children. The study was designed to evaluate the effects of oral liquid antibiotics on Streptococcus mutans growth and biofilm formation.

STUDY DESIGN: A 24 hour culture of S. mutans was treated with various concentrations of liquid medications commonly prescribed to children for odontogenic or fungal infections- amoxicillin, penicillin VK, clindamycin, and nystatin. The study was conducted in sterile 96-well flat bottom microtiter plates. The minimum inhibitory and biofilm inhibitory concentrations (MIC/MBIC) of S. mutans were determined for each medication. S. mutans was cultured with and without the test drugs, the amount of total growth measured, the biofilms washed, fixed, and stained with crystal violet. The absorbance was determined to evaluate biofilm formation.

RESULTS: Higher concentrations of amoxicillin, penicillin VK and clindamycin had decreased biofilm and overall growth than the control. The MICs were 1:2,560 (1.95 ug/ml), 1:2,560 (1.95 ug/ml) and 1:40 (9.375 ug/ml), while the MBIC were 1:640 (7.8 ug/ml), 1:1,280 (3.9 ug/ml) and 1:20 (18.75 ug/ml), respectively. Lower concentrations provided increased biofilm and overall growth. Nystatin induced significantly more biofilm and overall growth than the control at all concentrations.

CONCLUSION: At high concentrations, approximately at the levels expected to be present in the oral cavity of children, amoxicillin, penicillin, and clindamycin inhibited S. mutans biofilm and overall growth due to their antibiotic activity, while at lower concentrations the three antibiotics demonstrated an increase in biofilm and growth. The increase in S. mutans biofilm and overall growth is most likely attributed to the sugar content in the medications. Nystatin provided an increase in biofilm and growth at each concentration tested.}, } @article {pmid28287302, year = {2017}, author = {Ashrafi, M and Baguneid, M and Alonso-Rasgado, T and Rautemaa-Richardson, R and Bayat, A}, title = {Cutaneous wound biofilm and the potential for electrical stimulation in management of the microbiome.}, journal = {Future microbiology}, volume = {12}, number = {}, pages = {337-357}, doi = {10.2217/fmb-2016-0204}, pmid = {28287302}, issn = {1746-0921}, mesh = {Animals ; Bacteria/classification/genetics/isolation & purification/*radiation effects ; Biofilms/*radiation effects ; *Electric Stimulation ; Humans ; Microbiota/*radiation effects ; Skin Diseases, Bacterial/microbiology/*therapy ; Wound Infection/microbiology/*therapy ; }, abstract = {Infection contributes significantly to delayed cutaneous wound healing, which impacts patient care. External application of electrical stimulation (ES) has beneficial effects on wound repair and regeneration. The majority of studies to date have explored ES in relation to planktonic microorganisms, yet evidence indicates that bacteria in chronic wounds reside as antibiotic-resistant polymicrobial biofilms, which contribute to impairing wound healing. Culture-independent sequencing techniques have revolutionized our understanding of the skin microbiome and allowed a more accurate determination of microbial taxa and their relative abundance in wounds allowing a greater understanding of the host-microbial interface. Future studies combining the fields of ES, biofilm and microbiome research are necessary to fully elucidate the use of ES in the management of wound infection.}, } @article {pmid28286870, year = {2017}, author = {Kao, WT and Frye, M and Gagnon, P and Vogel, JP and Chole, R}, title = {D-amino acids do not inhibit Pseudomonas aeruginosa biofilm formation.}, journal = {Laryngoscope investigative otolaryngology}, volume = {2}, number = {1}, pages = {4-9}, pmid = {28286870}, issn = {2378-8038}, support = {P30 DC005209-15/NH/NIH HHS/United States ; 5T32DC000022-28/NH/NIH HHS/United States ; T35 DC008765/DC/NIDCD NIH HHS/United States ; R01 DC000263/DC/NIDCD NIH HHS/United States ; P30 DC005209/DC/NIDCD NIH HHS/United States ; T32 DC000022/DC/NIDCD NIH HHS/United States ; }, abstract = {OBJECTIVE: Pseudomonas aeruginosa, a known biofilm-forming organism, is an opportunistic pathogen that plays an important role in chronic otitis media, tracheitis, cholesteatoma, chronic wounds, and implant infections. Eradication of biofilm infections has been a challenge because the biofilm phenotype provides bacteria with a protective environment from the immune system and antibiotics; thus, there has been great interest in adjunctive molecules that may inhibit biofilm formation or cause biofilm dispersal. There are reports that D-amino acids may inhibit biofilms. In this study, we test the ability of various D-amino acids to inhibit P. aeruginosa biofilm formation in vitro.

STUDY DESIGN: We evaluated the effect of D-alanine (10 mM), D-leucine (10 mM), D-methionine (10 mM), D-tryptophan (10 mM), and D-tyrosine (10 uM and 1 mM) on biofilm formation in two commonly studied laboratory strains of P. aeruginosa: PAO1 and PA14.

METHODS: Biofilms were grown in 24-well and 96-well tissue culture plates, documented photographically and stained with 0.1% crystal violet and solubilized in 33% glacial acetic acid for quantification.

RESULTS: In strains PAO1 and PA14, the addition of D-amino acids did not result in an inhibitory effect on biofilm growth in 24-well plates. Repeating the study in 96-well plates confirmed our findings that D-amino acids do not inhibit biofilm formation of P. aeruginosa.

CONCLUSION: We conclude that D-amino acids only slow the production of biofilms rather than completely prevent biofilm formation; therefore, D-amino acids represent a poor option for potential clinically therapeutic interventions.

LEVEL OF EVIDENCE: N/A.}, } @article {pmid28285703, year = {2017}, author = {Li, S and Zhang, S and Ye, C and Lin, W and Zhang, M and Chen, L and Li, J and Yu, X}, title = {Biofilm processes in treating mariculture wastewater may be a reservoir of antibiotic resistance genes.}, journal = {Marine pollution bulletin}, volume = {118}, number = {1-2}, pages = {289-296}, doi = {10.1016/j.marpolbul.2017.03.003}, pmid = {28285703}, issn = {1879-3363}, mesh = {Anti-Bacterial Agents/*isolation & purification ; Bacteria/genetics ; *Biofilms ; Drug Resistance, Bacterial/*genetics ; *Genes, Bacterial ; Wastewater/*chemistry ; }, abstract = {Antibiotics are heavily used in Chinese mariculture, but only a small portion of the added antibiotics are absorbed by living creatures. Biofilm processes are universally used in mariculture wastewater treatment. In this study, removal of antibiotics (norfloxacin, rifampicin, and oxytetracycline) from wastewater by moving bed biofilm reactors (MBBRs) and the influence of antibiotics on reactor biofilm were investigated. The results demonstrated that there was no significant effect of sub-μg/L-sub-mg/L concentrations of antibiotics on TOC removal. Moreover, the relative abundance of antibiotic resistance genes (ARGs) and antibiotic resistance bacteria (ARB) in MBBR biofilm increased because of selective pressure of antibiotics. In addition, antibiotics decreased the diversity of the biofilm bacterial community and altered bacterial community structure. These findings provide an empirical basis for the development of appropriate practices for mariculture, and suggest that disinfection and advanced oxidation should be applied to eliminate antibiotics, ARGs, and ARB from mariculture wastewater.}, } @article {pmid28283813, year = {2017}, author = {Giannelli, M and Landini, G and Materassi, F and Chellini, F and Antonelli, A and Tani, A and Nosi, D and Zecchi-Orlandini, S and Rossolini, GM and Bani, D}, title = {Effects of photodynamic laser and violet-blue led irradiation on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide attached to moderately rough titanium surface: in vitro study.}, journal = {Lasers in medical science}, volume = {32}, number = {4}, pages = {857-864}, pmid = {28283813}, issn = {1435-604X}, mesh = {Animals ; Biofilms/*radiation effects ; Escherichia coli/drug effects/*radiation effects/ultrastructure ; Fluorescence ; Lasers, Semiconductor ; *Light ; Lipopolysaccharides/*pharmacology ; Mice ; Microbial Viability/radiation effects ; *Photochemotherapy ; RAW 264.7 Cells ; Staphylococcus aureus/drug effects/*radiation effects/ultrastructure ; Titanium/chemistry/*pharmacology ; }, abstract = {Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This study investigates the in vitro efficacy of photodynamic treatment (PDT) with methylene blue (MB) photoactivated with λ 635 nm diode laser and of λ 405 nm violet-blue LED phototreatment for the reduction of bacterial biofilm and lipopolysaccharide (LPS) adherent to titanium surface mimicking the bone-implant interface. Staphylococcus aureus biofilm grown on titanium discs with a moderately rough surface was subjected to either PDT (0.1% MB and λ 635 nm diode laser) or λ 405 nm LED phototreatment for 1 and 5 min. Bactericidal effect was evaluated by vital staining and residual colony-forming unit count. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, discs coated with Escherichia coli LPS were treated as above before seeding with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Both PDT and LED phototreatment induced a statistically significant (p < 0.05 or higher) reduction of viable bacteria, up to -99 and -98% (5 min), respectively. Moreover, besides bactericidal effect, PDT and LED phototreatment also inhibited LPS bioactivity, assayed as nitrite formation, up to -42%, thereby blunting host inflammatory response. Non-invasive phototherapy emerges as an attractive alternative in the treatment of peri-implantitis to reduce bacteria and LPS adherent to titanium implant surface without causing damage of surface microstructure. Its efficacy in the clinical setting remains to be investigated.}, } @article {pmid28283008, year = {2017}, author = {Karaman, M and Alvandian, A and Bahar, IH}, title = {[Galleria mellonella larva model in evaluating the effects of biofilm in Candida albicans].}, journal = {Mikrobiyoloji bulteni}, volume = {51}, number = {1}, pages = {32-40}, doi = {10.5578/mb.48622}, pmid = {28283008}, issn = {0374-9096}, mesh = {Animals ; *Biofilms ; Candida albicans/*physiology ; Disease Models, Animal ; Larva/microbiology ; Moths/*microbiology ; }, abstract = {Biofilm-related infections are chronic infections that cause serious increase in morbidity and mortality as well as significant economic loss. Galleria mellonella larva is shown as a reliable animal model for in vivo toxicology and pathogenicity tests due to its large size, ease of practice, ability to survive at 15-37°C and its similarity to mammals' natural immune system. The aim of this study was to evaluate the effects biofilm activity of Candida albicans in a G.mellonella larva model. Two C.albicans strains isolated as a disease agent were used for the model, where one was positive (BP), and the other one was negative (BN) for biofilm production. Eighty healthy G.mellonella larvae, all in the last larval stage and 2-2.5 cm long, were divided into 4 groups of equal size. Group 1 was set as the control group. Group 2 was injected with sterile phosphate buffer (PBS) group. Group 3 was injected with BP C.albicans strain and group 4 with BN C.albicans strain. A 5 μL volume of C.albicans prepared at 5 × 10[5] cfu/ml concentration with PBS was injected into the last left rear-legs of the larvae. The larvae were kept in sterile petri dishes at 37°C. They were observed for a total of 96 hours, for 4 hours in the first 24 hours, then in 12 hours intervals. Melanization, survival, total hemocyte count and fungal burden were evaluated as infection indicators. Melanization and death were not observed throughout the study period in group 1. One larva died in group 2. Small melanization spots (dark spots) and subsequent progressive melanization were observed from 3rd hour in the larvae infected with C.albicans. When compared with the BN C.albicans infected group, survival rate was 20% for BP C.albicans infected larvae at the end of 24 hours. Total hemocyte count was very low in the infected groups compared to groups 1 and 2, also significantly lower in group 3 than in group 4. In quantitative cultures, growth of C.albicans was detected in groups 3 and 4 while not in groups 1 and 2. Fungal load was significantly higher in BP C.albicans infected group than BN C.albicans infected group. In this study, G.mellonella larvae were used as live hosts to demonstrate the effects of biofilm activity of C.albicans. Our results suggest that larval models can be used to investigate the effects of fungal infections and biofilm like virulence factors on host cells, and invertebrate animal models can be widely used and can bridge between in vitro studies and mammalian models.}, } @article {pmid28283006, year = {2017}, author = {Öcal, DN and Dolapçı, İ and Karahan, ZC and Tekeli, A}, title = {[Investigation of biofilm formation properties of staphylococcus isolates].}, journal = {Mikrobiyoloji bulteni}, volume = {51}, number = {1}, pages = {10-19}, doi = {10.5578/mb.46552}, pmid = {28283006}, issn = {0374-9096}, mesh = {Bacteremia/microbiology ; Biofilms/*growth & development ; Carrier State/microbiology ; Catheters/microbiology ; Cross Infection/microbiology ; DNA Transposable Elements ; Humans ; N-Acetylglucosaminyltransferases/genetics/metabolism ; Nose/microbiology ; Operon/genetics ; Polysaccharides, Bacterial/physiology ; Staphylococcal Infections/*microbiology ; Staphylococcus/classification/*pathogenicity/*physiology ; Virulence ; }, abstract = {Biofilm production is an important virulence factor which allows staphylococci to adhere to medical devices. The principal component of biofilm is a "polysaccharide intercellular adhesin (PIA)" which is composed of a beta-1,6-N-acetylglucosamine polymer synthesized by an enzyme (N-acetylglucosamine transferase) encoded by the ica operon found on the bacterial chromosome. This operon is composed of four genes (A, B, C, and D), and a transposable element IS256. In this study, we aimed to determine the biofilm production characteristics of invasive/non-invasive staphylococcus isolates and different staphylococcus species. Biofilm production of 166 staphylococci was phenotypically investigated on Congo Red Agar (CRA); the presence of icaA, icaD and IS256 genes were investigated by polymerase chain reaction (PCR). 74 of the isolates (44.6%) were identified as methicillin resistant Staphylococcus aureus (MRSA), 25 (15.1%) as methicillin sensitive S.aureus (MSSA), 25 (37.3%) as Staphylococcus hominis, 20 (12%) as S.epidermidis, ten (15%) as Staphylococcus haemolyticus, nine (13.4%) as Staphylococcus capitis, two (3%) Staphylococcus saprophyticus and one (1.5%) as Staphylococcus warnerii. Of the MRSA strains, 52 were isolated from blood and 22 from nose; all MSSA strains were isolated from nose cultures. Coagulase-negative staphylococci (CoNS) strains were composed of invasive and non-invasive strains isolated from nose, catheter tip and blood cultures from patients with catheter. Production with CRA method was found to be statistically significant in invasive isolates (p< 0.001). It is concluded that; as the biofilm formation capacity of invasive isolates can cause refractory infections and the importance of carriage and hospital infections of these bacteria, it is important to prevent the spread of these isolates. A combination of phenotypic and genotypic tests is recommended for the investigation of biofilm formation in staphylococci. 40.3% of the CoNS isolates, and 85.8% of S.aureus isolates produced biofilm on CRA (p< 0.001) and with PCR method the ratio of carrying three genes was found to be statistically important in S.aureus when compared with CoNS. Carriage of three genes and biofilm formation capacity of invasive isolates can cause refractory infections and the importance of carriage and hospital infections of these bacteria, it is important to prevent the spread of these isolates. A combination of phenotypic and genotypic tests is recommended for the investigation of biofilm formation in staphylococci.}, } @article {pmid28282052, year = {2017}, author = {Altamura, L and Horvath, C and Rengaraj, S and Rongier, A and Elouarzaki, K and Gondran, C and Maçon, AL and Vendrely, C and Bouchiat, V and Fontecave, M and Mariolle, D and Rannou, P and Le Goff, A and Duraffourg, N and Holzinger, M and Forge, V}, title = {A synthetic redox biofilm made from metalloprotein-prion domain chimera nanowires.}, journal = {Nature chemistry}, volume = {9}, number = {2}, pages = {157-163}, doi = {10.1038/nchem.2616}, pmid = {28282052}, issn = {1755-4349}, mesh = {Catalysis ; Electrochemical Techniques ; Electrodes ; Electron Transport ; Laccase/chemistry/metabolism ; Metalloproteins/*chemistry ; Methanococcus/metabolism ; Microscopy, Atomic Force ; Nanowires/*chemistry ; Oxidation-Reduction ; Prions/*chemistry ; Rubredoxins/*chemistry ; }, abstract = {Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only bioelectrodes.}, } @article {pmid28281851, year = {2017}, author = {Besinis, A and Hadi, SD and Le, HR and Tredwin, C and Handy, RD}, title = {Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings.}, journal = {Nanotoxicology}, volume = {11}, number = {3}, pages = {327-338}, doi = {10.1080/17435390.2017.1299890}, pmid = {28281851}, issn = {1743-5404}, mesh = {Alloys/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Dental Implants ; Durapatite/*pharmacology ; Nanoparticles ; Silver/*pharmacology ; Titanium/*pharmacology ; }, abstract = {One of the most common causes of implant failure is peri-implantitis, which is caused by bacterial biofilm formation on the surfaces of dental implants. Modification of the surface nanotopography has been suggested to affect bacterial adherence to implants. Silver nanoparticles are also known for their antibacterial properties. In this study, titanium alloy implants were surface modified following silver plating, anodisation and sintering techniques to create a combination of silver, titanium dioxide and hydroxyapatite (HA) nanocoatings. Their antibacterial performance was quantitatively assessed by measuring the growth of Streptococcus sanguinis, proportion of live/dead cells and lactate production by the microbes over 24 h. Application of a dual layered silver-HA nanocoating to the surface of implants successfully inhibited bacterial growth in the surrounding media (100% mortality), whereas the formation of bacterial biofilm on the implant surfaces was reduced by 97.5%. Uncoated controls and titanium dioxide nanocoatings showed no antibacterial effect. Both silver and HA nanocoatings were found to be very stable in biological fluids with material loss, as a result of dissolution, to be less than 0.07% for the silver nanocoatings after 24 h in a modified Krebs-Ringer bicarbonate buffer. No dissolution was detected for the HA nanocoatings. Thus, application of a dual layered silver-HA nanocoating to titanium alloy implants creates a surface with antibiofilm properties without compromising the HA biocompatibility required for successful osseointegration and accelerated bone healing.}, } @article {pmid28280714, year = {2017}, author = {Casillo, A and Papa, R and Ricciardelli, A and Sannino, F and Ziaco, M and Tilotta, M and Selan, L and Marino, G and Corsaro, MM and Tutino, ML and Artini, M and Parrilli, E}, title = {Anti-Biofilm Activity of a Long-Chain Fatty Aldehyde from Antarctic Pseudoalteromonas haloplanktis TAC125 against Staphylococcus epidermidis Biofilm.}, journal = {Frontiers in cellular and infection microbiology}, volume = {7}, number = {}, pages = {46}, pmid = {28280714}, issn = {2235-2988}, mesh = {Aldehydes/chemistry/isolation & purification/*pharmacology ; Antarctic Regions ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Homoserine/analogs & derivatives/chemistry/isolation & purification/pharmacology ; Lactones/chemistry/isolation & purification/pharmacology ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Pseudoalteromonas/isolation & purification/*metabolism ; Staphylococcus epidermidis/*drug effects/*physiology ; Vibrio/drug effects ; }, abstract = {Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis.}, } @article {pmid28278777, year = {2018}, author = {Lu, YF and Ma, LJ and Ma, L and Shan, B and Chang, JJ}, title = {Improvement of start-up and nitrogen removal of the anammox process in reactors inoculated with conventional activated sludge using biofilm carrier materials.}, journal = {Environmental technology}, volume = {39}, number = {1}, pages = {59-67}, doi = {10.1080/09593330.2017.1294624}, pmid = {28278777}, issn = {1479-487X}, mesh = {Ammonium Compounds ; Biofilms/*growth & development ; Bioreactors/microbiology ; Charcoal ; Chemoautotrophic Growth ; Denitrification ; Nitrification ; Nitrites ; Nitrogen/analysis/*metabolism ; Oxidation-Reduction ; Sewage/microbiology ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*analysis/metabolism ; }, abstract = {The start-up of the anaerobic ammonium oxidation (anammox) process in three up-flow column reactors seeded with common mixed activated sludge and added with three materials, sponge (R1), sponge + volcanic rock (R2) and sponge + charcoal (R3), as carriers for biofilm formation were comparatively investigated in this study. The supplement of volcanic rock and charcoal could significantly shorten the start-up time of the anammox process, which primarily occurred in the activity-enhanced phase, with ammonium and nitrite removal efficiencies stabilized above 92.5% and 93.4% after an operation period of 145, 105 and 121 d for R1, R2 and R3, respectively. After the successful anammox start-up, R2 performed significantly better in TN removal (p < .05), achieving an average rate of 91.0% and 191.5 g N m[-3] d[-1] compared to R1 of 88.4% and 172.1 g N m[-3] d[-1], and R3 of 89.9% and 180.1 g N m[-3] d[-1] in the steady running phase. The ratios of consumed [Formula: see text] and generated [Formula: see text]/consumed [Formula: see text] after anammox start-up were lower than the theoretical values, probably suggesting the simultaneous existences of anammox, denitrification as well as nitrification processes in the reactors. A reddish brown biofilm was wrapped on the carriers and morphological detection of biofilm displayed the presentations of thick and compact floc aggregates and some filamentous bacteria on the sponge, and spherical-, ovoid- and shortrod-shaped microorganisms on the volcanic rock and charcoal. Using porous material as carrier for biofilm development is an effective strategy for practical application of the anammox reactor.}, } @article {pmid28278426, year = {2017}, author = {Logroño, W and Pérez, M and Urquizo, G and Kadier, A and Echeverría, M and Recalde, C and Rákhely, G}, title = {Single chamber microbial fuel cell (SCMFC) with a cathodic microalgal biofilm: A preliminary assessment of the generation of bioelectricity and biodegradation of real dye textile wastewater.}, journal = {Chemosphere}, volume = {176}, number = {}, pages = {378-388}, doi = {10.1016/j.chemosphere.2017.02.099}, pmid = {28278426}, issn = {1879-1298}, mesh = {Biodegradation, Environmental ; *Bioelectric Energy Sources ; Biofilms/*growth & development ; Coloring Agents/*analysis/chemistry ; Electricity ; Electrochemical Techniques ; Electrodes ; Microalgae/*metabolism ; Textiles ; Wastewater/*chemistry ; Water Pollutants, Chemical/*analysis/chemistry ; }, abstract = {An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%-43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m[-3]. The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92-98%), but the removal efficiencies were considerably lower for Cr (54-80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.}, } @article {pmid28278106, year = {2018}, author = {Sharafat, I and Saeed, DK and Yasmin, S and Imran, A and Zafar, Z and Hameed, A and Ali, N}, title = {Interactive effect of trivalent iron on activated sludge digestion and biofilm structure in attached growth reactor of waste tire rubber.}, journal = {Environmental technology}, volume = {39}, number = {2}, pages = {130-143}, doi = {10.1080/09593330.2017.1296894}, pmid = {28278106}, issn = {1479-487X}, mesh = {Biofilms/growth & development ; Bioreactors/microbiology ; In Situ Hybridization, Fluorescence ; *Iron ; Refuse Disposal/*methods ; *Rubber ; Sewage/chemistry ; Waste Products/*analysis ; }, abstract = {Waste tire rubber (WTR) has been introduced as an alternative, novel media for biofilm development in several experimental systems including attached growth bioreactors. In this context, four laboratory-scale static batch bioreactors containing WTR as a support material for biofilm development were run under anoxic condition for 90 days using waste activated sludge as an inoculum under the influence of different concentrations (2.5, 6.5, 8.5 mg/l) of trivalent ferric iron (Fe[3+]). The data revealed that activated sludge with a Fe[3+] concentration of 8.5 mg/l supported the maximum bacterial biomass [4.73E + 10 CFU/ml cm[2]]; besides, it removed 38% more Chemical oxygen demand compared to Fe[3+] free condition from the reactor. Biochemical testing and 16S rDNA phylogenetic analysis of WTR-derived biofilm communities further suggested the role of varying concentrations of Fe[3+] on the density and diversity of members of Enterobacteria(ceae), ammonium (AOB) and nitrite oxidizing bacteria. Furthermore, Fluorescent in situ hybridization with phylogenetic oligonucleotide probes and confocal laser scanning microscopy of WTR biofilms indicated a significant increase in density of eubacteria (3.00E + 01 to.05E + 02 cells/cm[2]) and beta proteobacteria (8.10E + 01 to 1.42E + 02 cells/cm[2]), respectively, with an increase in Fe[3+] concentration in the reactors, whereas, the cell density of gamma proteobacteria in biofilms decreased.}, } @article {pmid28278095, year = {2018}, author = {Gao, F and Li, Z and Chang, Q and Gao, M and She, Z and Wu, J and Jin, C and Zheng, D and Guo, L and Zhao, Y and Wang, S}, title = {Effect of florfenicol on performance and microbial community of a sequencing batch biofilm reactor treating mariculture wastewater.}, journal = {Environmental technology}, volume = {39}, number = {3}, pages = {363-372}, doi = {10.1080/09593330.2017.1301567}, pmid = {28278095}, issn = {1479-487X}, mesh = {Anti-Bacterial Agents/*analysis/toxicity ; *Aquaculture ; Biofilms/drug effects ; Bioreactors/*microbiology ; Thiamphenicol/*analogs & derivatives/analysis/toxicity ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry/microbiology ; Water Microbiology ; Water Pollutants, Chemical/*analysis/toxicity ; }, abstract = {The effects of florfenicol (FF) on the performance, microbial activity and microbial community of a sequencing batch biofilm reactor (SBBR) were evaluated in treating mariculture wastewater. The chemical oxygen demand (COD) and nitrogen removal were inhibited at high FF concentrations. The specific oxygen utilization rate (SOUR), specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR) and specific nitrate reduction rate (SNRR) were decreased with an increase in the FF concentration from 0 to 35 mg/L. The chemical compositions of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) could be affected with an increase in the FF concentration. The high-throughput sequencing indicated some obvious variations in the microbial community at different FF concentrations. The relative abundance of Nitrosomonas and Nitrospira showed a decreasing tendency with an increase in the FF concentration, suggesting that FF could affect the nitrification process of SBBR. Some genera capable of reducing nitrate to nitrogen gas could be inhibited by the addition of FF in the influent, such as Azospirillum and Hyphomicrobium.}, } @article {pmid28278088, year = {2018}, author = {Chatterjee, P and Ghangrekar, MM and Rao, S}, title = {Sludge granulation in an UASB-moving bed biofilm hybrid reactor for efficient organic matter removal and nitrogen removal in biofilm reactor.}, journal = {Environmental technology}, volume = {39}, number = {3}, pages = {298-307}, doi = {10.1080/09593330.2017.1299796}, pmid = {28278088}, issn = {1479-487X}, mesh = {Anaerobiosis ; Bacteria ; Biofilms ; Bioreactors/*microbiology ; Denitrification ; Nitrogen/analysis/*metabolism ; Sewage/chemistry/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Pollutants, Chemical/analysis/*metabolism ; }, abstract = {A hybrid upflow anaerobic sludge blanket (UASB)-moving bed biofilm (MBB) and rope bed biofilm (RBB) reactor was designed for treatment of sewage. Possibility of enhancing granulation in an UASB reactor using moving media to improve sludge retention was explored while treating low-strength wastewater. The presence of moving media in the top portion of the UASB reactor allowed a high solid retention time even at very short hydraulic retention times and helped in maintaining selection pressure in the sludge bed to promote formation of different sized sludge granules with an average settling velocity of 67 m/h. These granules were also found to contain plenty of extracellular polymeric substance (EPS) such as 58 mg of polysaccharides (PS) per gram of volatile suspended solids (VSS) and protein (PN) content of 37 mg/g VSS. Enriched sludge of nitrogen-removing bacteria forming a porous biofilm on the media in RBB was also observed in a concentration of around 894 g/m[2]. The nitrogen removing sludge also had a high EPS content of around 22 mg PS/g VSS and 28 mg PN/g VSS. This hybrid UASB-MBB-RBB reactor with enhanced anaerobic granular sludge treating both carbonaceous and nitrogenous matter may be a sustainable solution for decentralized sewage treatment.}, } @article {pmid28276583, year = {2018}, author = {Hoedke, D and Enseleit, C and Gruner, D and Dommisch, H and Schlafer, S and Dige, I and Bitter, K}, title = {Effect of photodynamic therapy in combination with various irrigation protocols on an endodontic multispecies biofilm ex vivo.}, journal = {International endodontic journal}, volume = {51 Suppl 1}, number = {}, pages = {e23-e34}, doi = {10.1111/iej.12763}, pmid = {28276583}, issn = {1365-2591}, mesh = {*Bacterial Load ; *Biofilms ; Combined Modality Therapy ; Dental Pulp Cavity/*microbiology ; Humans ; *Photochemotherapy ; Random Allocation ; *Root Canal Irrigants ; *Therapeutic Irrigation ; }, abstract = {AIM: To analyse the antibacterial effect of photodynamic therapy (PDT) in combination with various irrigation protocols on a multispecies biofilm in root canals ex vivo.

METHODOLOGY: A total of 160 extracted human single-rooted teeth were divided into four groups (n = 40). In group G1, root canals were instrumented up to size 60 (control group), whereas in G2 to G4 canals were enlarged up to size 40. All root canals were inoculated with a multispecies biofilm (Enterococcus faecalis, Streptococcus oralis, Prevotella intermedia) for 5 days. In G2 to G4, instrumentation up to size 60 was performed using 0.9% sodium chloride (NaCl) (G2), 1% sodium hypochlorite (NaOCl) (G3), 1% NaOCl and a final irrigation with 2% chlorhexidine (CHX) (G4), respectively. In all groups half of the specimens received adjunctive PDT using phenothiazine chloride as photosensitizer and a diode laser (wavelength 660 nm). Counts of colony-forming units (CFUs) in each group were analysed separately for planktonic and dentine-adherent bacteria immediately after therapy (T1) and after 5 days of further incubation (T2). Descriptive statistics and two-way analysis of variance were carried out to analyse reduction of planktonic bacteria and nonparametric tests were used to analyse dentine-adherent bacteria.

RESULTS: CFU reduction in planktonic bacteria was significantly affected by the irrigation protocol at T1 and T2 (P < 0.0001), but PDT significantly reduced CFUs only at T2 (P = 0.01; anova). Irrigation using NaOCl, CHX and adjunctive PDT significantly reduced CFUs at T2 (P < 0.0001; Tukey HSD) compared to the control group. In 85.6% of all samples the same categories of CFU counts in both planktonic and dentine-adherent bacteria were detected at T1 and T2.

CONCLUSIONS: Adjunctive photodynamic therapy in combination with an irrigation protocol including NaOCl and CHX was an effective method for reduction of bacterial biofilm inside the root canals of extracted teeth.}, } @article {pmid28275296, year = {2017}, author = {Attaran, B and Falsafi, T and Ghorbanmehr, N}, title = {Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics.}, journal = {World journal of gastroenterology}, volume = {23}, number = {7}, pages = {1163-1170}, pmid = {28275296}, issn = {2219-2840}, mesh = {Adult ; Amoxicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Child ; Clarithromycin/pharmacology ; *Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial ; Erythromycin/pharmacology ; Genes, Bacterial ; Helicobacter Infections/*drug therapy/microbiology ; Helicobacter pylori/*drug effects ; Humans ; Metronidazole/pharmacology ; Microbial Sensitivity Tests ; RNA, Ribosomal, 16S/genetics ; Real-Time Polymerase Chain Reaction ; Tetracycline/pharmacology ; }, abstract = {AIM: To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared.

METHODS: A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and hefA.

RESULTS: The strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic ones.

CONCLUSION: The present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.}, } @article {pmid28274550, year = {2017}, author = {Murakami, K and Ono, T and Noma, Y and Minase, I and Amoh, T and Irie, Y and Hirota, K and Miyake, Y}, title = {Explorative gene analysis of antibiotic tolerance-related genes in adherent and biofilm cells of Pseudomonas aeruginosa.}, journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy}, volume = {23}, number = {5}, pages = {271-277}, doi = {10.1016/j.jiac.2017.01.004}, pmid = {28274550}, issn = {1437-7780}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; Microbial Sensitivity Tests/methods ; Mutation/drug effects/genetics ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/*genetics ; }, abstract = {BACKGROUND: Antibiotic tolerance has attracted worldwide attention, as it leads to chronic, refractory, and persistent infections that are difficult to control. Bacterial biofilms are well known to be more tolerant to antibiotics compared to planktonic bacteria. We previously revealed that adherent bacteria on a solid surface also exhibited tolerance to antibiotics before forming a biofilm. However, little is known about the mechanisms of antibiotic tolerance for adherent or biofilm cells.

OBJECTIVES: We investigated the mechanisms of antibiotic tolerance in the biofilm life cycle using adherent and biofilm cells, and evaluated the possibility that common mechanisms operate at each stage.

METHODS: We constructed transposon mutants of Pseudomonas aeruginosa PAO1 and screened for low-tolerant mutants with two different methods, using adherent cells and biofilm cells.

RESULTS: Fourteen and nine mutants exhibiting low antibiotic tolerance were detected in the adherent cells and biofilm cells, and 14 and 7 candidate genes linked to this tolerance were identified by sequencing, respectively. Eight of the 14 genes related to the antibiotic tolerance of the adherent cells were involved in biofilm formation. Two of the seven genes related to the antibiotic tolerance of biofilm cells participated in the antibiotic tolerance of adherent cells.

CONCLUSIONS: The antibiotic tolerance of adherent cells and biofilm formation appear to be under the same regulation mechanism to promote survival in the presence of antibiotics. Antibiotic tolerance shows a complex regulation mechanism at each stage of biofilm formation.}, } @article {pmid28274217, year = {2017}, author = {Sharma, VK and Bayles, DO and Alt, DP and Looft, T and Brunelle, BW and Stasko, JA}, title = {Disruption of rcsB by a duplicated sequence in a curli-producing Escherichia coli O157:H7 results in differential gene expression in relation to biofilm formation, stress responses and metabolism.}, journal = {BMC microbiology}, volume = {17}, number = {1}, pages = {56}, pmid = {28274217}, issn = {1471-2180}, mesh = {Amino Acid Sequence ; Amino Acids/metabolism ; Bacterial Adhesion ; Base Sequence ; Biofilms/*growth & development ; Congo Red/metabolism ; Culture Media ; DNA, Bacterial ; DNA, Recombinant ; Down-Regulation ; Escherichia coli O157/*genetics/growth & development/*metabolism/physiology ; Escherichia coli Proteins/biosynthesis/*genetics/metabolism ; Fimbriae, Bacterial/genetics/metabolism ; Gene Expression Regulation, Bacterial/*genetics ; Genes, Bacterial/genetics ; Genetic Complementation Test ; Heat-Shock Proteins/genetics ; Hydrogen-Ion Concentration ; Membrane Proteins/genetics ; Microscopy, Electron, Transmission ; Osmotic Pressure ; Oxidative Stress ; Phenotype ; Polysaccharides/biosynthesis/genetics ; RNA, Bacterial/isolation & purification ; Sequence Alignment ; Stress, Physiological/*genetics ; Stress, Psychological/genetics ; Temperature ; Transcription Factors/*genetics ; Transcription, Genetic ; Up-Regulation ; }, abstract = {BACKGROUND: Escherichia coli O157:H7 (O157) strain 86-24, linked to a 1986 disease outbreak, displays curli- and biofilm-negative phenotypes that are correlated with the lack of Congo red (CR) binding and formation of white colonies (CR[-]) on a CR-containing medium. However, on a CR medium this strain produces red isolates (CR[+]) capable of producing curli fimbriae and biofilms.

RESULTS: To identify genes controlling differential expression of curli fimbriae and biofilm formation, the RNA-Seq profile of a CR[+] isolate was compared to the CR[-] parental isolate. Of the 242 genes expressed differentially in the CR[+] isolate, 201 genes encoded proteins of known functions while the remaining 41 encoded hypothetical proteins. Among the genes with known functions, 149 were down- and 52 were up-regulated. Some of the upregulated genes were linked to biofilm formation through biosynthesis of curli fimbriae and flagella. The genes encoding transcriptional regulators, such as CsgD, QseB, YkgK, YdeH, Bdm, CspD, BssR and FlhDC, which modulate biofilm formation, were significantly altered in their expression. Several genes of the envelope stress (cpxP), heat shock (rpoH, htpX, degP), oxidative stress (ahpC, katE), nutrient limitation stress (phoB-phoR and pst) response pathways, and amino acid metabolism were downregulated in the CR[+] isolate. Many genes mediating acid resistance and colanic acid biosynthesis, which influence biofilm formation directly or indirectly, were also down-regulated. Comparative genomics of CR[+] and CR[-] isolates revealed the presence of a short duplicated sequence in the rcsB gene of the CR[+] isolate. The alignment of the amino acid sequences of RcsB of the two isolates showed truncation of RcsB in the CR[+] isolate at the insertion site of the duplicated sequence. Complementation of CR[+] isolate with rcsB of the CR[-] parent restored parental phenotypes to the CR[+] isolate.

CONCLUSIONS: The results of this study indicate that RcsB is a global regulator affecting bacterial survival in growth-restrictive environments through upregulation of genes promoting biofilm formation while downregulating certain metabolic functions. Understanding whether rcsB inactivation enhances persistence and survival of O157 in carrier animals and the environment would be important in developing strategies for controlling this bacterial pathogen in these niches.}, } @article {pmid28273964, year = {2017}, author = {Bhardwaj, SB and Mehta, M and Sood, S and Sharma, J}, title = {Biofilm Formation by Drug Resistant Enterococci Isolates Obtained from Chronic Periodontitis Patients.}, journal = {Journal of clinical and diagnostic research : JCDR}, volume = {11}, number = {1}, pages = {DC01-DC03}, pmid = {28273964}, issn = {2249-782X}, abstract = {INTRODUCTION: Enterococci are an important cause of opportunistic nosocomial infections and several multidrug resistant strains have emerged. The severity of periodontal diseases is managed by reduction in the pathogenic bacteria. There is a need to assess the prevalence and antibiotic susceptibility of enterococci colonizing the periodontal pocket and correlate its biofilm formation ability because oral biofilms provide a protective environment and are a reservoir of bacterial colonization of the gingival crevice.

AIM: To investigate possible association between antibiotic susceptibility and biofilm formation in enterococci isolates from chronic periodontitis patients.

MATERIALS AND METHODS: This retrospective study was conducted at Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Punjab University, Chandigarh from January 2015 to October 2015. Sterile paper points were inserted in the periodontal pocket of 100 subjects and put in a transport media. Forty -six isolates were identified as enterococci. The isolates were further examined for their ability to form biofilm by microtitre plate assay and antimicrobial susceptibility testing was done by disc diffusion method for clinically relevant antibiotics.

RESULTS: Significant relationship (p<0.001) was found between biofilm production with antibiotic resistance to Vancomycin, Erythromycin, Ciprofloxacin, Tiecoplanin, Amoxycillin and Gentamycin.

CONCLUSION: The study demonstrates a high propensity among the isolates of Enterococci to form biofilm and a significant association of biofilm with multiple drug resistance.}, } @article {pmid28273443, year = {2017}, author = {Zhong, L and Lai, CY and Shi, LD and Wang, KD and Dai, YJ and Liu, YW and Ma, F and Rittmann, BE and Zheng, P and Zhao, HP}, title = {Nitrate effects on chromate reduction in a methane-based biofilm.}, journal = {Water research}, volume = {115}, number = {}, pages = {130-137}, doi = {10.1016/j.watres.2017.03.003}, pmid = {28273443}, issn = {1879-2448}, mesh = {*Biofilms ; Bioreactors ; *Chromates ; Methane ; Nitrates ; Oxidation-Reduction ; }, abstract = {The effects of nitrate (NO3[-]) on chromate (Cr(VI)) reduction in a membrane biofilm reactor (MBfR) were studied when CH4 was the sole electron donor supplied with a non-limiting delivery capacity. A high surface loading of NO3[-] gave significant and irreversible inhibition of Cr(VI) reduction. At a surface loading of 500 mg Cr/m[2]-d, the Cr(VI)-removal percentage was 100% when NO3[-] was absent (Stage 1), but was dramatically lowered to < 25% with introduction of 280 mg N m[-2]-d NO3[-] (Stage 2). After ∼50 days operation in Stage 2, the Cr(VI) reduction recovered to only ∼70% in Stage 3, when NO3[-] was removed from the influent; thus, NO3[-] had a significant long-term inhibition effect on Cr(VI) reduction. Weighted PCoA and UniFrac analyses proved that the introduction of NO3[-] had a strong impact on the microbial community in the biofilms, and the changes possibly were linked to the irreversible inhibition of Cr(VI) reduction. For example, Meiothermus, the main genus involved in Cr(VI) reduction at first, declined with introduction of NO3[-]. The denitrifier Chitinophagaceae was enriched after the addition of NO3[-], while Pelomonas became important when nitrate was removed, suggesting its potential role as a Cr(VI) reducer. Moreover, introducing NO3[-] led to a decrease in the number of genes predicted (by PICRUSt) to be related to chromate reduction, but genes predicted to be related to denitrification, methane oxidation, and fermentation increased.}, } @article {pmid28271122, year = {2017}, author = {McDonough, RT and Zheng, H and Alila, MA and Goodisman, J and Chaiken, J}, title = {Optical interference probe of biofilm hydrology: label-free characterization of the dynamic hydration behavior of native biofilms.}, journal = {Journal of biomedical optics}, volume = {22}, number = {3}, pages = {35003}, doi = {10.1117/1.JBO.22.3.035003}, pmid = {28271122}, issn = {1560-2281}, mesh = {*Biofilms ; Escherichia coli/physiology ; Microbiological Techniques/*methods ; Microscopy, Confocal ; *Optical Imaging ; Pseudomonas aeruginosa/physiology ; Water/*metabolism ; }, abstract = {Biofilm produced by Escherichia coli (E. coli) or Pseudomonas aeruginosa (P. aeruginosa) on quartz or polystyrene is removed from the culture medium and drained. Observed optical interference fringes indicate the presence of a layer of uniform thickness with refractive index different from air-dried biofilm. Fringe wavelengths indicate that layer optical thickness is < 20 ?? ? m or 1 to 2 orders of magnitude thinner than the biofilm as measured by confocal Raman microscopy or fluorescence imaging of the bacteria. Raman shows that films have an alginate-like carbohydrate composition. Fringe amplitudes indicate that the refractive index of the interfering layer is higher than dry alginate. Drying and rehydration nondestructively thins and restores the interfering layer. The strength of the 1451-nm near infrared water absorption varies in unison with thickness. Absorption and layer thickness are proportional for films with different bacteria, substrates, and growth conditions. Formation of the interfering layer is general, possibly depending more on the chemical nature of alginate-like materials than bacterial processes. Films grown during the exponential growth phase produce no observable interference fringes, indicating requirements for layer formation are not met, possibly reflecting bacterial activities at that stage. The interfering layer might provide a protective environment for bacteria when water is scarce.}, } @article {pmid28270055, year = {2017}, author = {Cattò, C and Grazioso, G and Dell'Orto, S and Gelain, A and Villa, S and Marzano, V and Vitali, A and Villa, F and Cappitelli, F and Forlani, F}, title = {The response of Escherichia coli biofilm to salicylic acid.}, journal = {Biofouling}, volume = {33}, number = {3}, pages = {235-251}, doi = {10.1080/08927014.2017.1286649}, pmid = {28270055}, issn = {1029-2454}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Biomass ; Escherichia coli/drug effects/metabolism/*physiology ; Escherichia coli Proteins/metabolism ; Indoles/metabolism ; Quorum Sensing/*drug effects ; Reactive Oxygen Species/metabolism ; Salicylic Acid/*pharmacology ; }, abstract = {In this research, salicylic acid is proposed as an alternative biocide-free agent suitable for a preventive or integrative anti-biofilm approach. Salicylic acid has been proved to: (1) reduce bacterial adhesion up to 68.1 ± 5.6%; (2) affect biofilm structural development, reducing viable biomass by 97.0 ± 0.7% and extracellular proteins and polysaccharides by 83.9 ± 2.5% and 49.5 ± 5.5% respectively; and (3) promote biofilm detachment 3.4 ± 0.6-fold. Moreover, salicylic acid treated biofilm showed an increased amount of intracellular (2.3 ± 0.2-fold) and extracellular (2.1 ± 0.3-fold) reactive oxygen species, and resulted in increased production of the quorum sensing signal indole (7.6 ± 1.4-fold). For the first time, experiments revealed that salicylic acid interacts with proteins that play a role in quorum sensing, reactive oxygen species accumulation, motility, extracellular polymeric matrix components, transport and metabolism.}, } @article {pmid28270052, year = {2017}, author = {López Pérez, D and Baker, PJ and Pintar, AL and Sun, J and Lin, NJ and Lin-Gibson, S}, title = {Experimental and statistical methods to evaluate antibacterial activity of a quaternary pyridinium salt on planktonic, biofilm-forming, and biofilm states.}, journal = {Biofouling}, volume = {33}, number = {3}, pages = {222-234}, doi = {10.1080/08927014.2017.1286476}, pmid = {28270052}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Data Interpretation, Statistical ; Dose-Response Relationship, Drug ; Humans ; Microbial Sensitivity Tests ; Models, Statistical ; Plankton/drug effects/*physiology ; Pyridinium Compounds/chemical synthesis/chemistry/*pharmacology ; Streptococcus mutans/drug effects/*physiology ; }, abstract = {Robust evaluation and comparison of antimicrobial technologies are critical to improving biofilm prevention and treatment. Herein, a multi-pronged experimental framework and statistical models were applied to determine the effects of quaternary pyridinium salt, 4-acetyl-1-hexadecylpyridin-1-ium iodide (QPS-1), on Streptococcus mutans in the planktonic, biofilm-forming and biofilm cell states. Minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined via common methods with novel application of statistical approaches combining random effects models and interval censored data to estimate uncertainties. The MICs and MBCs for planktonic and biofilm-forming states ranged from 3.12 to 12.5 μg ml[-1], with biofilm values only ≈ 8 times higher. Potent anti-biofilm activity and reactive structural features make QPS-1 a promising antibacterial additive for dental and potentially other biomedical devices. Together, the experimental framework and statistical models provide estimates and uncertainties for effective antimicrobial concentrations in multiple cell states, enabling statistical comparisons and improved characterization of antibacterial agents.}, } @article {pmid28270050, year = {2017}, author = {Qian, J and Horn, H and Tarchitzky, J and Chen, Y and Katz, S and Wagner, M}, title = {Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography.}, journal = {Biofouling}, volume = {33}, number = {3}, pages = {211-221}, doi = {10.1080/08927014.2017.1285017}, pmid = {28270050}, issn = {1029-2454}, mesh = {Agricultural Irrigation/*instrumentation ; Biofilms/*growth & development ; Biofouling/prevention & control ; Desert Climate ; Lab-On-A-Chip Devices/*microbiology ; *Models, Theoretical ; *Temperature ; Tomography, Optical Coherence ; Wastewater/chemistry/microbiology ; Water Movements ; Water Purification/methods ; *Water Quality ; Water Supply/methods/standards ; }, abstract = {Drip irrigation is a water-saving technology. To date, little is known about how biofilm forms in drippers of irrigation systems. In this study, the internal dripper geometry was recreated in 3-D printed microfluidic devices (MFDs). To mimic the temperature conditions in (semi-) arid areas, experiments were conducted in a temperature controlled box between 20 and 50°C. MFDs were either fed with two different treated wastewater (TWW) or synthetic wastewater. Biofilm formation was monitored non-invasively and in situ by optical coherence tomography (OCT). 3-D OCT datasets reveal the major fouling position and illustrate that biofilm development was influenced by fluid dynamics. Biofilm volumetric coverage of the labyrinth up to 60% did not reduce the discharge rate, whereas a further increase to 80% reduced the discharge rate by 50%. Moreover, the biofilm formation rate was significantly inhibited in daily temperature cycle independent of the cultivation medium used.}, } @article {pmid28267679, year = {2017}, author = {Singh, DP and Gowda, AU and Chopra, K and Tholen, M and Chang, S and Mavrophilipos, V and Semsarzadeh, N and Rasko, Y and Holton Iii, L}, title = {The Effect of Negative Pressure Wound Therapy With Antiseptic Instillation on Biofilm Formation in a Porcine Model of Infected Spinal Instrumentation.}, journal = {Wounds : a compendium of clinical research and practice}, volume = {28}, number = {6}, pages = {175-180}, pmid = {28267679}, issn = {1943-2704}, mesh = {Animals ; Anti-Infective Agents, Local/pharmacology ; Bacterial Load/drug effects ; Biofilms/*drug effects/growth & development ; Bone Diseases, Infectious/microbiology/*therapy ; Disease Models, Animal ; Equipment Contamination ; Internal Fixators/*microbiology ; Microscopy, Electron, Scanning ; *Negative-Pressure Wound Therapy ; Prosthesis-Related Infections/microbiology/*therapy ; Spine/microbiology/*pathology ; Staphylococcal Infections/microbiology/*therapy ; Swine ; Wound Healing ; }, abstract = {OBJECTIVE: This study evaluates the effect of negative pressure wound therapy with antiseptic instillation (NPWTi) in the clearance of infection and biofilm formation in an in vivo model of infected spinal implants compared to traditional treatment modalities.

MATERIALS AND METHODS: Five pigs underwent titanium rod implantation of their spinous processes followed by injection of 1 x 106 CFUs/100μL of methicillin-resistant Staphylococcus aureus through the fascia at each site. At 1 week postoperatively, an experimental arm of 3 pigs received NPWTi, and a control arm of 2 pigs received wet-to-dry dressings. The persistence of local infection in the experimental group was compared to the control group using tissue cultures. Biofilm development on spinal implants was evaluated using scanning electron microscopy.

RESULTS: Mean bacterial count showed a statistical difference between the experimental and the control groups (P < .05). Scanning electron microscopy revealed the presence of uniform biofilm formation across the surface of control group instrumentation, whereas the experimental group showed interrupted areas between biofilm formations.

CONCLUSION: The authors concluded that NPWTi is associated with decreased bacterial load and biofilm formation compared to wet-to-dry dressings in an in vivo porcine model of infected spinal instrumentation.}, } @article {pmid28267594, year = {2017}, author = {Klinger-Strobel, M and Stein, C and Forstner, C and Makarewicz, O and Pletz, MW}, title = {Effects of colistin on biofilm matrices of Escherichia coli and Staphylococcus aureus.}, journal = {International journal of antimicrobial agents}, volume = {49}, number = {4}, pages = {472-479}, doi = {10.1016/j.ijantimicag.2017.01.005}, pmid = {28267594}, issn = {1872-7913}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colistin/*pharmacology ; Colony Count, Microbial ; Escherichia coli/*drug effects/isolation & purification/*physiology ; Escherichia coli Infections/microbiology ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/isolation & purification/*physiology ; Microbial Viability/drug effects ; Microscopy, Confocal ; Staining and Labeling ; Staphylococcal Infections/microbiology ; }, abstract = {Biofilms are the preferred environment of micro-organisms on various surfaces such as catheters and heart valves, are associated with numerous difficult-to-treat and recurrent infections, and confer an extreme increase in antibiotic tolerance to most compounds. The aim of this study was to evaluate how colistin affects both the extracellular biofilm matrix and the embedded bacteria in biofilms of methicillin-resistant Staphylococcus aureus (MRSA), a species with intrinsic resistance to colistin, and colistin-susceptible Escherichia coli. Biofilms of MRSA and E. coli were treated with different concentrations of colistin. The minimum biofilm eradication concentration (MBEC) and the effectiveness of colistin at reducing the planktonic fraction were defined as the remaining viable bacteria measured as CFU/mL. In addition, biofilm-embedded cells were LIVE/DEAD-stained and were analysed by confocal laser scanning microscopy (CLSM). Quantification of the biofilm CLSM images was conducted using an open-access in-house algorithm (qBA). In contrast to MRSA, E. coli biofilms and planktonic cells were significantly reduced by colistin in a concentration-dependent manner. Nevertheless, colistin has been shown to exert a matrix-reducing effect following treatment both in laboratory strains and clinical isolates of MRSA and E. coli. Because exposure to colistin rapidly triggered the emergence of highly resistant clones, monotherapy with colistin should be applied with caution. These results suggest that colistin destabilises the biofilm matrix structure even in species with intrinsic colistin resistance, such as S. aureus, leading to the release of planktonic cells that are more susceptible to antibiotics.}, } @article {pmid28266111, year = {2017}, author = {Marsh, PD and Zaura, E}, title = {Dental biofilm: ecological interactions in health and disease.}, journal = {Journal of clinical periodontology}, volume = {44 Suppl 18}, number = {}, pages = {S12-S22}, doi = {10.1111/jcpe.12679}, pmid = {28266111}, issn = {1600-051X}, mesh = {*Biofilms ; Humans ; *Microbial Interactions ; Microbiota ; Mouth Diseases/*microbiology ; *Oral Health ; Tooth/*microbiology ; }, abstract = {BACKGROUND: The oral microbiome is diverse and exists as multispecies microbial communities on oral surfaces in structurally and functionally organized biofilms.

AIM: To describe the network of microbial interactions (both synergistic and antagonistic) occurring within these biofilms and assess their role in oral health and dental disease.

METHODS: PubMed database was searched for studies on microbial ecological interactions in dental biofilms. The search results did not lend themselves to systematic review and have been summarized in a narrative review instead.

RESULTS: Five hundred and forty-seven original research articles and 212 reviews were identified. The majority (86%) of research articles addressed bacterial-bacterial interactions, while inter-kingdom microbial interactions were the least studied. The interactions included physical and nutritional synergistic associations, antagonism, cell-to-cell communication and gene transfer.

CONCLUSIONS: Oral microbial communities display emergent properties that cannot be inferred from studies of single species. Individual organisms grow in environments they would not tolerate in pure culture. The networks of multiple synergistic and antagonistic interactions generate microbial inter-dependencies and give biofilms a resilience to minor environmental perturbations, and this contributes to oral health. If key environmental pressures exceed thresholds associated with health, then the competitiveness among oral microorganisms is altered and dysbiosis can occur, increasing the risk of dental disease.}, } @article {pmid28266013, year = {2017}, author = {Wagner, M and Horn, H}, title = {Optical coherence tomography in biofilm research: A comprehensive review.}, journal = {Biotechnology and bioengineering}, volume = {114}, number = {7}, pages = {1386-1402}, doi = {10.1002/bit.26283}, pmid = {28266013}, issn = {1097-0290}, mesh = {Bacteria/*cytology/*growth & development ; Biofilms/*growth & development ; Image Enhancement/*methods ; Image Interpretation, Computer-Assisted/*methods ; Reproducibility of Results ; Research ; Research Design ; Sensitivity and Specificity ; Tomography, Optical Coherence/*methods ; }, abstract = {Imaging of biofilm systems is a prerequisite for a better understanding of both structure and its function. The review aims to critically discuss the use of optical coherence tomography (OCT) for the visualization of the biofilm structure as well as its dynamic behavior. A short overview on common and well-known, established imaging techniques for biofilms such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), Raman microscopy (RM), and magnetic resonance imaging (MRI) paves the way to imaging biofilms at the mesoscale, which is perfectly covered by means of OCT. Principle, resolution, imaging velocity, and limitations of OCT are subsequently presented and discussed in the context of biofilm applications. Examples are provided showing the strength of this technique with respect to the visualization of the mesoscopic biofilm structure as well as the estimation of flow profiles and shear rates. Common and new structural parameters derived from OCT datasets are presented. Additionally, the review shows the importance of OCT with respect to a better description of mechanical biofilm properties. Finally, the implementation of multi-dimensional OCT datasets in biofilm modelling is shown by several examples aiming on an improved understanding of mass transfer at the bulk-biofilm interface. Biotechnol. Bioeng. 2017;114: 1386-1402. © 2017 Wiley Periodicals, Inc.}, } @article {pmid28263451, year = {2017}, author = {Galarraga-Vinueza, ME and Passoni, B and Benfatti, CAM and Mesquita-Guimarães, J and Henriques, B and Magini, RS and Fredel, MC and Meerbeek, BV and Teughels, W and Souza, JCM}, title = {Inhibition of multi-species oral biofilm by bromide doped bioactive glass.}, journal = {Journal of biomedical materials research. Part A}, volume = {105}, number = {7}, pages = {1994-2003}, doi = {10.1002/jbm.a.36056}, pmid = {28263451}, issn = {1552-4965}, mesh = {Bacteria/*growth & development ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bromides/*chemistry ; Glass/*chemistry ; Mouth/*microbiology ; }, abstract = {Bioactive glass is an attractive biomaterial that has shown excellent osteogenic and angiogenic effects for oral bone repairing procedures. However, anti-biofilm potential related to such biomaterial has not been completely validated, mainly against multi-species biofilms involved in early tissue infections. The aim of the present study was to evaluate the anti-biofilm effect of 58 S bioactive glass embedding calcium bromide compounds at different concentrations. Bioactive glass free or containing 5, or 10 wt % CaBr2 was synthesized by alkali sol-gel method and then characterized by physco-chemical analyses and scanning electron microscopy (SEM). Then, samples were tested by microbiological assays using optical density, real time q-PCR, and SEM. Bioactive glass particles showed accurate chemical composition and an angular shape with a bimodal size distribution ranging from 0.6 to 110 µm. The mean particle size was around 29 µm. Anti-biofilm effect was recorded for 5 wt % CaBr2 -doped bioactive glass against S. mitis, V. parvula, P. gingivais, S. gordoni, A. viscosus, F, nucleatum, P. gingivais. F. nucleatum, and P. gingivalis. Such species are involved in the biofilm structure related to infections on hard and soft tissues in the oral cavity. The incorporation of calcium bromide into bioactive glass can be a strategy to enhance the anti-biofilm potential of bioactive glasses for bone healing and infection treatment. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1994-2003, 2017.}, } @article {pmid28263038, year = {2017}, author = {Petrova, OE and Gupta, K and Liao, J and Goodwine, JS and Sauer, K}, title = {Divide and conquer: the Pseudomonas aeruginosa two-component hybrid SagS enables biofilm formation and recalcitrance of biofilm cells to antimicrobial agents via distinct regulatory circuits.}, journal = {Environmental microbiology}, volume = {19}, number = {5}, pages = {2005-2024}, pmid = {28263038}, issn = {1462-2920}, support = {R01 AI080710/AI/NIAID NIH HHS/United States ; R01 AI150761/AI/NIAID NIH HHS/United States ; R21 AI119726/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives ; Drug Resistance, Multiple, Bacterial/*genetics ; Gene Expression Regulation, Bacterial/*genetics ; Histidine Kinase/*genetics ; Mutagenesis, Site-Directed ; Protein Domains/genetics ; Pseudomonas aeruginosa/genetics/*growth & development ; Signal Transduction/genetics ; }, abstract = {The opportunistic pathogen Pseudomonas aeruginosa forms antimicrobial resistant biofilms through sequential steps requiring several two-component regulatory systems. The sensor-regulator hybrid SagS plays a central role in biofilm development by enabling the switch from the planktonic to the biofilm mode of growth, and by facilitating the transition of biofilm cells to a highly tolerant state. However, the mechanism by which SagS accomplishes both functions is unknown. SagS harbours a periplasmic sensory HmsP, and phosphorelay HisKA and Rec domains. SagS domain was used as constructs and site-directed mutagenesis to elucidate how SagS performs its dual functions. It was demonstrated that HisKA-Rec and the phospho-signalling between SagS and BfiS contribute to the switch to the biofilm mode of growth, but not to the tolerant state. Instead, expression of SagS domain constructs harbouring HmsP rendered ΔsagS biofilm cells as recalcitrant to antimicrobial agents as wild-type biofilms, likely by restoring BrlR production and cellular c-di-GMP levels to wild-type levels. Restoration of biofilm tolerance by HmsP was independent of biofilm biomass accumulation, RsmA, RsmYZ, HptB and BfiSR-downstream targets. Our findings thus suggest that SagS likely makes use of a "divide-and-conquer" mechanism to regulate its dual switch function, by activating two distinct regulatory networks via its individual domains.}, } @article {pmid28261188, year = {2017}, author = {Balasubramanian, S and Othman, EM and Kampik, D and Stopper, H and Hentschel, U and Ziebuhr, W and Oelschlaeger, TA and Abdelmohsen, UR}, title = {Marine Sponge-Derived Streptomyces sp. SBT343 Extract Inhibits Staphylococcal Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {236}, pmid = {28261188}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to absence of cell toxicity, the extract might represent a good starting material to develop a future remedy to block staphylococcal biofilm formation on contact lenses and thereby to prevent intractable contact lens-mediated ocular infections.}, } @article {pmid28260589, year = {2017}, author = {Sabaeifard, P and Abdi-Ali, A and Gamazo, C and Irache, JM and Soudi, MR}, title = {Improved effect of amikacin-loaded poly(D,L-lactide-co-glycolide) nanoparticles against planktonic and biofilm cells of Pseudomonas aeruginosa.}, journal = {Journal of medical microbiology}, volume = {66}, number = {2}, pages = {137-148}, doi = {10.1099/jmm.0.000430}, pmid = {28260589}, issn = {1473-5644}, mesh = {Amikacin/chemistry/*pharmacology ; Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Cell Survival/drug effects ; Drug Resistance, Multiple, Bacterial ; Lactic Acid/*chemistry ; Macrophages/drug effects ; Mice ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Polyglycolic Acid/*chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/*drug effects ; RAW 264.7 Cells ; }, abstract = {PURPOSE: Amikacin is one of the most effective antibiotics against Pseudomonas aeruginosa infections, but because of its high toxicity, the use of this antibiotic has been clinically limited. In the present study, amikacin was successfully loaded into a new formulation of nanoparticles (NPs) based on poly(d,l-lactide-co-glycolide) 50 : 50 in order to enhance the treatment efficacy. The synthetized amikacin-loaded PLGA nanoparticles with high drug loading and stability were used to eliminate P. aeruginosa cells in planktonic and biofilm states.

METHODOLOGY: P. aeruginosa PAO1 biofilm susceptibility studies were done using the minimum biofilm eradication concentration assay. The association of fluorescently labeled amikacin-loaded nanoparticles (A-NPs) with mouse monocyte macrophage cells (RAW 264.7), and the nanoparticles ability to interact and eradicate the bacterial cells even in the form of biofilms, was investigated using Flow cytometric studies and confocal laser scanning microscopy.

RESULTS: Flow cytometric studies showed that these NPs were able to interact with planktonic and biofilm bacterial cells. Moreover, following 1 h of incubation of A-NPs with 1-day-old biofilm, it was found that particles penetrate through the entire biofilm thickness. Live/dead fluorescent staining followed by CLSM analysis showed that the A-NPs were more effective than free drug in biofilm eradication.

CONCLUSION: The good antibacterial and antibiofilm activities of A-NPs, in addition to their ability to enter macrophages without any cytotoxicity for these cells, make them a potential candidate to treat P. aeruginosa infections.}, } @article {pmid28259957, year = {2017}, author = {Li, X and Liu, Z and Liu, H and Chen, X and Liu, Y and Tan, H}, title = {Photodynamic inactivation of fibroblasts and inhibition of Staphylococcus epidermidis adhesion and biofilm formation by toluidine blue O.}, journal = {Molecular medicine reports}, volume = {15}, number = {4}, pages = {1816-1822}, doi = {10.3892/mmr.2017.6184}, pmid = {28259957}, issn = {1791-3004}, mesh = {Animals ; Bacterial Adhesion/drug effects ; Biofilms/drug effects ; Cell Line ; Cells, Cultured ; Fibroblasts/*drug effects ; Humans ; Mice ; *Photochemotherapy ; Photosensitizing Agents/*pharmacology ; Staphylococcal Skin Infections/*drug therapy ; Staphylococcus epidermidis/*drug effects ; Tolonium Chloride/*pharmacology ; }, abstract = {Treating skin and soft tissue infections of severe limb traumas can be challenging. Crucial concerns focus on inhibiting biofilm formation by antibiotic‑resistant bacteria, and preventing scar formation by fibroblastic hyperproliferation. The local use of toluidine blue O (TBO)‑mediated photodynamic therapy (PDT) may be a promising strategy for treating such lesions. The present study used Staphylococcus epidermidis (strain ATCC 35984) to assess the effects of TBO‑PDT on bacterial adherence and biofilm formation, using confocal laser scanning microscopy (CLSM), tissue culture plating (TCP) and scanning electron microscopy (SEM). Primary human fibroblast cells were used to evaluate the cytotoxicity of TBO‑PDT using the 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay and CLSM. Six different treatment groups were investigated: Medium only [tryptone soy broth (TSB) or Dulbecco's modified Eagle's medium (DMEM)]; red light control (light dose, 30 J/cm2); TBO group (50 mM TBO); TBO‑PDT1 (TBO irradiated with 10 J/cm2); TBO‑PDT2 (TBO irradiated with 20 J/cm2); and TBO‑PDT3 (TBO irradiated with 30 J/cm2). The results of the S. epidermidis adhesion assay indicated that the TSB, light and TBO groups exhibited significant bacterial adherence, compared with the TBO‑PDT groups. Analysis of biofilm formation revealed significant light dose‑dependent differences between the TBO‑PDT groups and the TSB, light, and TBO groups. Furthermore, SEM indicated fewer colony masses in the TBO‑PDT groups compared with the control groups. The MTT assay for fibroblastic cell toxicity demonstrated ~1.1, 4.6, 14.5, 29.7 and 43.4% reduction in optical density for the light, TBO, TBO‑PDT1, TBO‑PDT2 and TBO‑PDT3 groups, respectively, compared with the DMEM control group. There was no difference in toxicity between the light and control groups, however, there were significant differences among the TBO‑PDT groups. Finally, alterations in fibroblast morphology and cell spreading were revealed by CLSM, following TBO‑PDT treatment. TBO‑PDT inhibited bacterial adhesion and biofilm formation, and exhibited significant cytotoxic effects on human fibroblasts. These results indicate that the local use of TBO‑PDT in limb lesions may be a useful treatment method for inhibiting bacterial biofilm formation and fibroblastic hyperproliferation, which may prevent infectious hypertrophic scar formation.}, } @article {pmid28259672, year = {2017}, author = {Zhu, T and Zhao, Y and Wu, Y and Qu, D}, title = {The Staphylococcus epidermidis gdpS regulates biofilm formation independently of its protein-coding function.}, journal = {Microbial pathogenesis}, volume = {105}, number = {}, pages = {264-271}, doi = {10.1016/j.micpath.2017.02.045}, pmid = {28259672}, issn = {1096-1208}, mesh = {Bacterial Proteins/genetics/metabolism ; Base Sequence ; Biofilms/*growth & development ; Blotting, Western/methods ; Cyclic GMP/*analogs & derivatives/genetics/metabolism ; DNA, Bacterial/genetics/isolation & purification ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Mutagenesis, Site-Directed/methods ; Staphylococcus epidermidis/enzymology/genetics/metabolism/*physiology ; Transcription Factors/genetics/metabolism ; Transcription, Genetic ; }, abstract = {The second messenger cyclic di-guanylate (c-di-GMP) plays an important role in controlling the switch between planktonic and biofilm lifestyles. The synthesis of c-di-GMP is catalyzed by di-guanylate cyclases (DGCs) and the enzymes are characterized by the presence of a conserved GGDEF domain. In the sequenced staphylococcal genomes, gdpS is the only gene encoding a GGDEF domain-containing protein. Previous studies have shown that gdpS contributes to staphylococcal biofilm formation, but its effect remains under debate. In the present study, we deleted gdpS in Staphylococcus epidermidis strain RP62A. Disruption of gdpS in this strain impaired biofilm formation under both static and dynamic flow conditions, suggesting that gdpS act as a positive regulator of biofilm development in this high-biofilm-forming isolate. The predicted translational start site of gdpS in S. epidermidis differs between the Refseq database and the Genbank database. By using site-directed mutagenesis and Western blot analysis, we determined GdpS is translated from the start codon annotated in the Refseq database. In addition, mutation in the GGDEF domain did not affect the ability of gdpS to complement the biofilm defect of the gdpS mutant. Heterologous di-guanylate cyclases expressed in trans failed to complement the gdpS mutant. These results confirmed that gdpS modulates staphylococcal biofilm independently of c-di-GMP signaling pathway. Furthermore, mutations of the start codon did not abolish the capacity of gdpS to enhance biofilm formation. Taken together, these findings indicated that the S. epidermidis gdpS regulates biofilm formation independently of its protein-coding function.}, } @article {pmid28258990, year = {2017}, author = {Li, J and Li, H and Zheng, J and Zhang, L and Fu, Q and Zhu, X and Liao, Q}, title = {Response of anodic biofilm and the performance of microbial fuel cells to different discharging current densities.}, journal = {Bioresource technology}, volume = {233}, number = {}, pages = {1-6}, doi = {10.1016/j.biortech.2017.02.083}, pmid = {28258990}, issn = {1873-2976}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Biomass ; Electrodes ; Textiles ; }, abstract = {To better understand the responses of anodic biofilm and MFC performance, five identical MFCs started at 100Ω were operated with different discharging current densities (0.3, 1.6, 3.0, 3.6 and 4.8A/m[2], denoted as MFC-0.3, MFC-1.6, MFC-3.0, MFC-3.6 and MFC-4.8, respectively). It was demonstrated that the discharging current would significantly influence biofilm development and MFC performance. Compared with the original MFC started at 100Ω, the performance of MFC-0.3 and MFC-1.6 decreased, whereas MFC-3.0 and MFC-3.6 exhibited improved maximum power densities. This was attributed to the reduced charge transfer resistance resulting from the increased active biomass after increasing discharging current. This indicated that the increasing discharging current could enhance active biomass and performance. However, a high discharging current density (4.8A/m[2]) caused the exfoliation of carbon particles from the carbon cloth and then the detachment of the anode biofilm, resulting in the cell failure of MFC-4.8.}, } @article {pmid28258668, year = {2017}, author = {Al-Wrafy, F and Brzozowska, E and Górska, S and Gamian, A}, title = {Pathogenic factors of Pseudomonas aeruginosa - the role of biofilm in pathogenicity and as a target for phage therapy.}, journal = {Postepy higieny i medycyny doswiadczalnej (Online)}, volume = {71}, number = {0}, pages = {78-91}, doi = {10.5604/01.3001.0010.3792}, pmid = {28258668}, issn = {1732-2693}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/growth & development ; Cross Infection/prevention & control ; Drug Resistance, Microbial ; Humans ; Phage Therapy/*methods ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/growth & development ; Virulence Factors ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that can cause several acute and chronic infections in humans, and it has become an important cause of nosocomial infections and antibiotic resistance. Biofilm represents an important virulence factor for these bacteria, plays a role in P. aeruginosa infections and avoidance of immune defence mechanisms, and has the ability to protect the bacteria from antibiotics. Alginate, Psl and Pel, three exopolysaccharides, are the main components in biofilm matrix, with many biological functions attributed to them, especially with respect to the protection of the bacterial cell from antibiotics and the immune system. Pseudomonas infections, biofilm formation and development of resistance to antibiotics all require better understanding to achieve the best results using alternative treatment with phage therapy. This review describes the P. aeruginosa pathogenicity and virulence factors with a special focus on the biofilm and its role in infection and resistance to antibiotics and summarizes phage therapy as an alternative approach in treatment of P. aeruginosa infections.}, } @article {pmid28258230, year = {2017}, author = {Richter, K and Van den Driessche, F and Coenye, T}, title = {Innovative approaches to treat Staphylococcus aureus biofilm-related infections.}, journal = {Essays in biochemistry}, volume = {61}, number = {1}, pages = {61-70}, doi = {10.1042/EBC20160056}, pmid = {28258230}, issn = {1744-1358}, mesh = {Animals ; *Biofilms ; Drug Repositioning ; Gallium/pharmacology/therapeutic use ; Humans ; *Inventions ; Quorum Sensing/drug effects ; Staphylococcal Infections/*drug therapy/*microbiology ; Staphylococcus aureus/drug effects/*physiology ; }, abstract = {Many bacterial infections in humans and animals are caused by bacteria residing in biofilms, complex communities of attached organisms embedded in an extracellular matrix. One of the key properties of microorganisms residing in a biofilm is decreased susceptibility towards antimicrobial agents. This decreased susceptibility, together with conventional mechanisms leading to antimicrobial resistance, makes biofilm-related infections increasingly difficult to treat and alternative antibiofilm strategies are urgently required. In this review, we present three such strategies to combat biofilm-related infections with the important human pathogen Staphylococcus aureus: (i) targeting the bacterial communication system with quorum sensing (QS) inhibitors, (ii) a 'Trojan Horse' strategy to disturb iron metabolism by using gallium-based therapeutics and (iii) the use of 'non-antibiotics' with antibiofilm activity identified through screening of repurposing libraries.}, } @article {pmid28256706, year = {2018}, author = {Leone, F and Bellani, L and Muccifora, S and Giorgetti, L and Bongioanni, P and Simili, M and Maserti, B and Del Carratore, R}, title = {Analysis of extracellular vesicles produced in the biofilm by the dimorphic yeast Pichia fermentans.}, journal = {Journal of cellular physiology}, volume = {233}, number = {4}, pages = {2759-2767}, doi = {10.1002/jcp.25885}, pmid = {28256706}, issn = {1097-4652}, mesh = {*Biofilms ; Culture Media ; Extracellular Vesicles/*metabolism/ultrastructure ; Fungal Proteins/metabolism ; MicroRNAs/metabolism ; Microbial Viability ; Pichia/cytology/*physiology/ultrastructure ; RNA, Fungal/metabolism ; }, abstract = {The yeast Pichia fermentans DISAABA 726 strain (P. fermentans) is a dimorphic yeast that under different environmental conditions may switch from a yeast-like to pseudohyphal morphology. We hypothesize that exosomes-like vesicles (EV) could mediate this rapid modification. EV are membrane-derived vesicles carrying lipids, proteins, mRNAs and microRNAs and have been recognized as important mediators of intercellular communication. Although it has been assumed for a long time that fungi release EV, knowledge of their functions is still limited. In this work we analyze P. fermentans EV production during growth in two different media containing urea (YCU) or methionine (YCM) where yeast-like or pseudohyphal morphology are produced. We developed a procedure to extract EV from the neighboring biofilm which is faster and more efficient as compared to the widely used ultracentrifugation method. Differences in morphology and RNA content of EV suggest that they might have an active role during dimorphic transition as response to the growth conditions. Our findings are coherent with a general state of hypoxic stress of the pseudohyphal cells.}, } @article {pmid28256611, year = {2017}, author = {Crabbé, A and Liu, Y and Matthijs, N and Rigole, P and De La Fuente-Nùñez, C and Davis, R and Ledesma, MA and Sarker, S and Van Houdt, R and Hancock, RE and Coenye, T and Nickerson, CA}, title = {Antimicrobial efficacy against Pseudomonas aeruginosa biofilm formation in a three-dimensional lung epithelial model and the influence of fetal bovine serum.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {43321}, pmid = {28256611}, issn = {2045-2322}, support = {R33 AI098701/AI/NIAID NIH HHS/United States ; RC4 HL106625/HL/NHLBI NIH HHS/United States ; MOP-123477//CIHR/Canada ; }, mesh = {A549 Cells ; Amikacin/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Cattle ; Cell Culture Techniques ; Colistin/pharmacology ; Drug Synergism ; Fetus ; Gentamicins/pharmacology ; Humans ; Lung/drug effects/microbiology/ultrastructure ; Microbial Sensitivity Tests ; Models, Biological ; Oligopeptides/*pharmacology ; Pseudomonas aeruginosa/*drug effects/growth & development ; Serum/*chemistry ; Tight Junctions/drug effects/microbiology/ultrastructure ; Tobramycin/pharmacology ; }, abstract = {In vitro models that mimic in vivo host-pathogen interactions are needed to evaluate candidate drugs that inhibit bacterial virulence traits. We established a new approach to study Pseudomonas aeruginosa biofilm susceptibility on biotic surfaces, using a three-dimensional (3-D) lung epithelial cell model. P. aeruginosa formed antibiotic resistant biofilms on 3-D cells without affecting cell viability. The biofilm-inhibitory activity of antibiotics and/or the anti-biofilm peptide DJK-5 were evaluated on 3-D cells compared to a plastic surface, in medium with and without fetal bovine serum (FBS). In both media, aminoglycosides were more efficacious in the 3-D cell model. In serum-free medium, most antibiotics (except polymyxins) showed enhanced efficacy when 3-D cells were present. In medium with FBS, colistin was less efficacious in the 3-D cell model. DJK-5 exerted potent inhibition of P. aeruginosa association with both substrates, only in serum-free medium. DJK-5 showed stronger inhibitory activity against P. aeruginosa associated with plastic compared to 3-D cells. The combined addition of tobramycin and DJK-5 exhibited more potent ability to inhibit P. aeruginosa association with both substrates. In conclusion, lung epithelial cells influence the efficacy of most antimicrobials against P. aeruginosa biofilm formation, which in turn depends on the presence or absence of FBS.}, } @article {pmid28256492, year = {2017}, author = {Beldüz, N and Kamburoğlu, A and Yılmaz, Y and Tosun, I and Beldüz, M and Kara, C}, title = {Evaluation of candida albicans biofilm formation on various dental restorative material surfaces.}, journal = {Nigerian journal of clinical practice}, volume = {20}, number = {3}, pages = {355-360}, doi = {10.4103/1119-3077.198388}, pmid = {28256492}, issn = {1119-3077}, mesh = {Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/*physiology ; Compomers/pharmacology ; Composite Resins/pharmacology ; Dental Amalgam/pharmacology ; Dental Materials/*pharmacology ; Dental Restoration, Permanent/instrumentation ; Disk Diffusion Antimicrobial Tests ; Glass Ionomer Cements/pharmacology ; Microscopy, Electron, Scanning ; Surface Properties ; }, abstract = {AIMS: Candida adhesion to any oral substrata is the first and essential stage in forming a pathogenic fungal biofilm. In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, nonbiological surfaces, such as restorative dental materials. This study compared the susceptibility of six dental restorative materials to Candida albicans adhesion.

MATERIALS AND METHODS: Cylindrical samples of each material were made according to the manufacturersa instructions. The antifungal effect of the samples on C. albicans was determined with the disc-diffusion method. The samples were put in plates with sterile Mueller Hinton and Sabouraud dextrose agar previously seeded with C. albicans. After the incubation period, the inhibition zone around each sample was evaluated. To evaluate the biofilm formation, the XTT technique and scanning electron microscopy (SEM) were used.

RESULTS: No inhibition zone was observed around the samples. According to the XTT assays, the amalgam samples revealed the lowest quantity of biofilm formation (P > 0.001). The highest median XTT values, significantly higher than the other materials (P < 0.001), were found for the composite and the compomer samples. Within the SEM examination, the amount of candidal growth was significantly lower on the resin-modified glass ionomer and glass-ionomer cement samples. The compomer and the composite samples showed more candidal adhesion.

CONCLUSION: This finding emphasizes the use of glass ionomer restorative cements and amalgam to reduce C. albicans adhesion to dental restorative materials especially in people with weakened immune systems, neutropenia, and cancer.}, } @article {pmid28255686, year = {2017}, author = {Gökalsın, B and Aksoydan, B and Erman, B and Sesal, NC}, title = {Reducing Virulence and Biofilm of Pseudomonas aeruginosa by Potential Quorum Sensing Inhibitor Carotenoid: Zeaxanthin.}, journal = {Microbial ecology}, volume = {74}, number = {2}, pages = {466-473}, pmid = {28255686}, issn = {1432-184X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Quorum Sensing/*drug effects ; Virulence/*drug effects ; Zeaxanthins/*pharmacology ; }, abstract = {Pseudomonas aeruginosa can regulate its virulence gene expressions by using a signal system called quorum sensing. It is known that inhibition of quorum sensing can block biofilm formation and leave the bacteria defenseless. Therefore, it is necessary to determine natural sources to obtain potential quorum sensing inhibitors. This study aims to investigate an alternative treatment approach by utilizing the carotenoid zeaxanthin to reduce the expressions of P. aeruginosa virulence factors through quorum sensing inhibition. The inhibition potential of zeaxanthin was determined by in silico screening from a library of 638 lichen metabolites. Fluorescent monitor strains were utilized for quorum sensing inhibitor screens, and quantitative reverse-transcriptase PCR assay was performed for evaluating gene expression. Results indicate that zeaxanthin is a better inhibitor than the lichen secondary metabolite evernic acid, which was previously shown to be capable of inhibiting P. aeruginosa quorum sensing systems.}, } @article {pmid28254875, year = {2017}, author = {Algburi, A and Comito, N and Kashtanov, D and Dicks, LMT and Chikindas, ML}, title = {Erratum for Algburi et al., Control of Biofilm Formation: Antibiotics and Beyond.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {6}, pages = {}, doi = {10.1128/AEM.00165-17}, pmid = {28254875}, issn = {1098-5336}, } @article {pmid28252025, year = {2017}, author = {Manner, S and Goeres, DM and Skogman, M and Vuorela, P and Fallarero, A}, title = {Prevention of Staphylococcus aureus biofilm formation by antibiotics in 96-Microtiter Well Plates and Drip Flow Reactors: critical factors influencing outcomes.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {43854}, pmid = {28252025}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriological Techniques/instrumentation/*methods ; Biofilms/*drug effects/growth & development ; Doxycycline/pharmacology ; Humans ; Microbial Sensitivity Tests ; Oxacillin/pharmacology ; Rifampin/pharmacology ; Staphylococcal Infections/microbiology/*prevention & control ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Biofilm formation leads to the failure of antimicrobial therapy. Thus, biofilm prevention is a desirable goal of antimicrobial research. In this study, the efficacy of antibiotics (doxycycline, oxacillin and rifampicin) in preventing Staphylococcus aureus biofilms was investigated using Microtiter Well Plates (MWP) and Drip Flow Reactors (DFR), two models characterized by the absence and the presence of a continuous flow of nutrients, respectively. Planktonic culture of S. aureus was exposed to antibiotics for one hour followed by 24 hours incubation with fresh nutrients in MWP or continuous flow of nutrients in DFR. The DFR grown biofilms were significantly more tolerant to the antibiotics than those grown in MWP without the continuous flow. The differences in log reductions (LR) between the two models could not be attributed to differences in the cell density, the planktonic inoculum concentration or the surface-area-to-volume ratios. However, eliminating the flow in the DFR significantly restored the antibiotic susceptibility. These findings demonstrate the importance of considering differences between experimental conditions in different model systems, particularly the flow of nutrients, when performing anti-biofilm efficacy evaluations. Biofilm antibiotic efficacy studies should be assessed using various models and more importantly, in a model mimicking conditions of its clinical application.}, } @article {pmid28244230, year = {2017}, author = {Mohmmed, SA and Vianna, ME and Penny, MR and Hilton, ST and Mordan, N and Knowles, JC}, title = {Confocal laser scanning, scanning electron, and transmission electron microscopy investigation of Enterococcus faecalis biofilm degradation using passive and active sodium hypochlorite irrigation within a simulated root canal model.}, journal = {MicrobiologyOpen}, volume = {6}, number = {4}, pages = {}, pmid = {28244230}, issn = {2045-8827}, mesh = {Biofilms/drug effects/*growth & development ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/drug effects/growth & development/*physiology ; Image Processing, Computer-Assisted ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Models, Theoretical ; Root Canal Irrigants/*administration & dosage ; Sodium Hypochlorite/*administration & dosage ; Therapeutic Irrigation ; Treatment Outcome ; }, abstract = {Root canal irrigation is an important adjunct to control microbial infection. The aim of this study was to investigate the effect of 2.5% (wt/vol) sodium hypochlorite (NaOCl) agitation on the removal, killing, and degradation of Enterococcus faecalis biofilm. A total of 45 root canal models were manufactured using 3D printing with each model comprising an 18 mm length simulated root canal of apical size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3 mm of the models for 10 days. A total of 60 s of 9 ml of 2.5% NaOCl irrigation using syringe and needle was performed, the irrigant was either left stagnant in the canal or agitated using manual (Gutta-percha), sonic, and ultrasonic methods for 30 s. Following irrigation, the residual biofilms were observed using confocal laser scanning, scanning electron, and transmission electron microscopy. The data were analyzed using one-way ANOVA with Dunnett post hoc tests at a level of significance p ≤ .05. Consequence of root canal irrigation indicate that the reduction in the amount of biofilm achieved with the active irrigation groups (manual, sonic, and ultrasonic) was significantly greater when compared with the passive and untreated groups (p < .05). Collectively, finding indicate that passive irrigation exhibited more residual biofilm on the model surface than irrigant agitated by manual or automated (sonic, ultrasonic) methods. Total biofilm degradation and nonviable cells were associated with the ultrasonic group.}, } @article {pmid28242464, year = {2017}, author = {Wang, XX and Fang, F and Chen, YP and Guo, JS and Li, K and Wang, H}, title = {N2O micro-profiles in biofilm from a one-stage autotrophic nitrogen removal system by microelectrode.}, journal = {Chemosphere}, volume = {175}, number = {}, pages = {482-489}, doi = {10.1016/j.chemosphere.2017.02.026}, pmid = {28242464}, issn = {1879-1298}, mesh = {Ammonium Compounds/metabolism ; Autotrophic Processes ; Bacteria, Anaerobic/metabolism ; *Biofilms ; Bioreactors/*microbiology ; *Denitrification ; Hydroxylamine/analysis ; Nitrification ; Nitrous Oxide/*analysis ; Oxidation-Reduction ; Oxygen/analysis ; Sewage/microbiology ; Wastewater/microbiology ; Water Purification/*methods ; }, abstract = {Emission of nitrous oxide (N2O), a greenhouse gas, is of growing concern in biological wastewater treatment. N2O emission from biofilm in a one-stage completely autotrophic nitrogen removal system was investigated using microelectrodes in this study. It is indicated that the pathways of nitrogen transformation in biofilm mainly included partial nitrification and anaerobic ammonium oxidation (anammox), also included nitrification and heterotrophic denitrification (HD). Ammonium-oxidizing bacteria (AOB) denitrification and HD were the main pathways resulting in N2O production in the biofilm, and hydroxylamine (NH2OH) oxidation was a subordinate pathway. In addition, the amount of N2O emission in test in which both NH4[+] and NO2[-] were added (NH4[+]-N: NO2[-]-N = 1:1) was about 2 times greater than that in test with NH4[+] addition only. This result expressed that NO2[-] is an important factor affecting N2O production in the biofilm. In conclusion, the present study provides a theoretical support for reducing N2O production in one-stage completely autotrophic nitrogen removal system.}, } @article {pmid28242178, year = {2017}, author = {Dawn, LE and Henry, GD and Tan, GK and Wilson, SK}, title = {Biofilm and Infectious Agents Present at the Time of Penile Prosthesis Revision Surgery: Times Are a Changing.}, journal = {Sexual medicine reviews}, volume = {5}, number = {2}, pages = {236-243}, doi = {10.1016/j.sxmr.2017.01.002}, pmid = {28242178}, issn = {2050-0521}, mesh = {*Biofilms ; Humans ; Male ; Penile Prosthesis/adverse effects/*microbiology ; Reoperation ; }, abstract = {INTRODUCTION: Although infection rates have decreased with the use of antibiotic-coated implants and other enhancements, the risk of infection is still considered a serious concern in penile implant revision surgeries.

AIM: To review the literature for advances made in inflatable penile prosthesis (IPP) revision surgery and organisms found at the time of revision, the significance of biofilm in prosthetic infection, and the bacteriology of infection.

METHODS: PubMed was reviewed for articles spanning the past three decades that discussed micro-organisms and biofilm in relation to penile implant revision surgery.

MAIN OUTCOME MEASURES: All articles were reviewed for evidence of bacteria found at revision IPP surgeries and any improvements made in surgical techniques and prosthesis enhancements.

RESULTS: During the period examined, several improvements have lowered the rate of infection in penile implant surgery: notably, antibiotic-coated IPPs, revision washout, and alcohol-based skin preparations. The biofilm composition on clinically uninfected and infected IPPs appears to have changed over time. The abundance of staphylococcal species-particularly coagulase-negative organisms-in positive cultures has decreased in infected implants, and clinically uninfected implants also have shown a decrease in the proportion of staphylococcal species. Conversely, other isolates such as fungi, Escherichia coli, and Enterococcus species have increased in clinically uninfected and infected implants, and there has been an overall increase in unique isolates that form the biofilm.

CONCLUSION: A multitude of enhancements has decreased the presence of micro-organisms and the subsequent formation of biofilm. Nevertheless, the formation of biofilm on penile implants has been noted more frequently in the past decade, and the microbial composition of biofilms seems to be changing. Dawn LE, Henry GD, Tan GK, Wilson SK. Biofilm and Infectious Agents Present at the Time of Penile Prosthesis Revision Surgery: Times Are a Changing. Sex Med Rev 2017;5:236-243.}, } @article {pmid28241058, year = {2017}, author = {Hardy, L and Jespers, V and Van den Bulck, M and Buyze, J and Mwambarangwe, L and Musengamana, V and Vaneechoutte, M and Crucitti, T}, title = {The presence of the putative Gardnerella vaginalis sialidase A gene in vaginal specimens is associated with bacterial vaginosis biofilm.}, journal = {PloS one}, volume = {12}, number = {2}, pages = {e0172522}, pmid = {28241058}, issn = {1932-6203}, mesh = {Adolescent ; Adult ; *Biofilms ; Female ; Gardnerella vaginalis/*enzymology/genetics ; Humans ; Hydrolysis ; In Situ Hybridization, Fluorescence ; Microscopy, Confocal ; Mucous Membrane/microbiology ; N-Acetylneuraminic Acid/chemistry ; Neuraminidase/*genetics ; Peptide Nucleic Acids/chemistry ; Polymerase Chain Reaction ; Polysaccharides/chemistry ; Rwanda ; Vagina/*microbiology ; Vaginosis, Bacterial/*enzymology ; Young Adult ; }, abstract = {Bacterial vaginosis (BV) is a difficult-to-treat recurrent condition in which health-associated lactobacilli are outnumbered by other anaerobic bacteria, such as Gardnerella vaginalis. Certain genotypes of G. vaginalis can produce sialidase, while others cannot. Sialidase is known to facilitate the destruction of the protective mucus layer on the vaginal epithelium by hydrolysis of sialic acid on the glycans of mucous membranes. This process possibly facilitates adhesion of bacterial cells on the epithelium since it has been linked with the development of biofilm in other pathogenic conditions. Although it has not been demonstrated yet, it is probable that G. vaginalis benefits from this mechanism by attaching to the vaginal epithelium to initiate biofilm development. In this study, using vaginal specimens of 120 women enrolled in the Ring Plus study, we assessed the association between the putative G. vaginalis sialidase A gene by quantitative polymerase chain reaction (qPCR), the diagnosis of BV according to Nugent score, and the occurrence of a BV-associated biofilm dominated by G. vaginalis by fluorescence in situ hybridisation (FISH). We detected the putative sialidase A gene in 75% of the G. vaginalis-positive vaginal specimens and found a strong association (p<0.001) between the presence of a G. vaginalis biofilm, the diagnosis of BV according to Nugent and the detection of high loads of the G. vaginalis sialidase A gene in the vaginal specimens. These results could redefine diagnosis of BV, and in addition might guide research for new treatment.}, } @article {pmid28240279, year = {2017}, author = {Dumitrache, A and Klingeman, DM and Natzke, J and Rodriguez, M and Giannone, RJ and Hettich, RL and Davison, BH and Brown, SD}, title = {Specialized activities and expression differences for Clostridium thermocellum biofilm and planktonic cells.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {43583}, pmid = {28240279}, issn = {2045-2322}, mesh = {*Biofilms ; Biomarkers ; Biomass ; Biosynthetic Pathways ; Carbohydrate Metabolism ; Clostridium thermocellum/*genetics/*growth & development/metabolism ; Energy Metabolism ; Fermentation ; *Gene Expression Regulation ; Gene Expression Regulation, Bacterial ; Lipid Metabolism ; Oxidative Stress ; Plankton/*genetics/*growth & development/metabolism ; Stress, Physiological ; }, abstract = {Clostridium (Ruminiclostridium) thermocellum is a model organism for its ability to deconstruct plant biomass and convert the cellulose into ethanol. The bacterium forms biofilms adherent to lignocellulosic feedstocks in a continuous cell-monolayer in order to efficiently break down and uptake cellulose hydrolysates. We developed a novel bioreactor design to generate separate sessile and planktonic cell populations for omics studies. Sessile cells had significantly greater expression of genes involved in catabolism of carbohydrates by glycolysis and pyruvate fermentation, ATP generation by proton gradient, the anabolism of proteins and lipids and cellular functions critical for cell division consistent with substrate replete conditions. Planktonic cells had notably higher gene expression for flagellar motility and chemotaxis, cellulosomal cellulases and anchoring scaffoldins, and a range of stress induced homeostasis mechanisms such as oxidative stress protection by antioxidants and flavoprotein co-factors, methionine repair, Fe-S cluster assembly and repair in redox proteins, cell growth control through tRNA thiolation, recovery of damaged DNA by nucleotide excision repair and removal of terminal proteins by proteases. This study demonstrates that microbial attachment to cellulose substrate produces widespread gene expression changes for critical functions of this organism and provides physiological insights for two cells populations relevant for engineering of industrially-ready phenotypes.}, } @article {pmid28239484, year = {2017}, author = {Oh, SY and Yun, W and Lee, JH and Lee, CH and Kwak, WK and Cho, JH}, title = {Effects of essential oil (blended and single essential oils) on anti-biofilm formation of Salmonella and Escherichia coli.}, journal = {Journal of animal science and technology}, volume = {59}, number = {}, pages = {4}, pmid = {28239484}, issn = {2055-0391}, abstract = {BACKGROUND: Biofilms were the third-dimensional structure in the solid surface of bacteria. Bacterial biofilms were difficult to control by host defenses and antibiotic therapies. Escherichia coli (E. coli) and Salmonella were popular pathogenic bacteria that live in human and animal intestines. Essential oils are aromatic oily liquids from plant materials and well known for their antibacterial activities.

METHOD: This study was conducted to determine effect of essential oil on anti-biological biofilm formation of E. coli and Salmonella strains in in vitro experiment. Two kinds of bacterial strains were separated from 0.2 g pig feces. Bacterial strains were distributed in 24 plates per treatment and each plates as a replication. The sample was coated with a Bacterial biofilm formation was.

RESULT: Photographic result, Escherichia coli (E. coli) and Salmonella bacteria colony surface were thick smooth surface in control. However, colony surface in blended and single essential oil treatment has shown crack surface layer compared with colony surfaces in control.

CONCLUSION: In conclusion, this study could confirm that essential oils have some interesting effect on anti-biofilm formation of E. coli and Salmonella strains from pig feces.}, } @article {pmid28237899, year = {2017}, author = {Zhai, S and Zhao, Y and Ji, M and Qi, W}, title = {Simultaneous removal of nitrate and chromate in groundwater by a spiral fiber based biofilm reactor.}, journal = {Bioresource technology}, volume = {232}, number = {}, pages = {278-284}, doi = {10.1016/j.biortech.2017.01.076}, pmid = {28237899}, issn = {1873-2976}, mesh = {*Bioreactors ; Carbon/chemistry/isolation & purification/pharmacokinetics ; Chromates/*isolation & purification/pharmacokinetics ; Denitrification ; Groundwater/*chemistry ; *Micropore Filters ; Nitrates/*isolation & purification/pharmacokinetics ; Nitrites/isolation & purification/pharmacokinetics ; Nitrogen/chemistry/isolation & purification/pharmacokinetics ; Water Purification/*methods ; }, abstract = {A spiral fiber based biofilm reactor was developed to remove nitrate and chromate simultaneously. The denitrification and Cr(VI) removal efficiency was evaluated with synthetic groundwater (NO3[-]-N=50mg/L) under different Cr(VI) concentrations (0-1.0mg/L), carbon nitrogen ratios (C/N) (0.8-1.2), hydraulic retention times (HRT) (2-16h) and initial pHs (4-10). Nitrate and Cr(VI) were completely removed without nitrite accumulation when the Cr(VI) concentration was lower than 0.4mg/L. As Cr(VI) up to 1.0mg/L, the system was obviously inhibited, but it recovered rapidly within 6days due to the strong adaption and domestication of microorganisms in the biofilm reactor. The results demonstrated that high removal efficiency of nitrate (≥99%) and Cr(VI) (≥95%) were achieved at lower C/N=0.9, HRT=8h, initial pH=7, and Cr(VI)=1.0mg/L. The technology proposed in present study can be alternative for simultaneous removal of co-contaminants in groundwater.}, } @article {pmid28237766, year = {2017}, author = {Eroshenko, D and Polyudova, T and Korobov, V}, title = {N-acetylcysteine inhibits growth, adhesion and biofilm formation of Gram-positive skin pathogens.}, journal = {Microbial pathogenesis}, volume = {105}, number = {}, pages = {145-152}, doi = {10.1016/j.micpath.2017.02.030}, pmid = {28237766}, issn = {1096-1208}, mesh = {Acetylcysteine/*pharmacology ; Adhesins, Bacterial/metabolism ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Gram-Negative Bacteria/cytology/*drug effects/metabolism/physiology ; Gram-Negative Bacterial Infections/microbiology ; Gram-Positive Bacteria/cytology/*drug effects/metabolism/physiology ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; Skin/*microbiology ; Skin Diseases, Bacterial/microbiology ; }, abstract = {N-Acetylcysteine (NAC) is a non-antibiotic drug with antimicrobial properties against biofilm phenotypes of Gram-positive and Gram-negative bacteria. Our aim was to assess the effects of NAC on the growth of Gram-positive human skin and mucous membrane pathogens in the planktonic and biofilm phases. The minimum inhibitory concentrations (MICs) of NAC against Enterococcus faecalis, Corynebacterium ammoniagenes, Mycobacterium smegmatis, Propionibacterium acnes, Staphylococcus aureus, S. epidermidis, Streptococcus pyogenes, and 14 clinical strains of coagulase-negative staphylococci (CNS) ranged from 0.098 to 25 mg/ml. We found that at sub-MICs of NAC the adherence of E. faecalis, S. epidermidis, and nine CNS strains significantly reduced. However, biofilm formation of E. faecalis, S. aureus and two CNS strains increased at sub-MICs of NAC. Furthermore, a dose-related decrease in biofilm formation of C. ammoniagenes, M. smegmatis, P. acnes, S. pyogenes, and S. epidermidis was observed. The effect of NAC on planktonic growth and biofilm formation of the M. smegmatis cell was also time-dependent. We have selected P. acnes VKM Ac-1450 Rif[r] strain with total resistance to rifampicin and used this microorganism for multispecies P. acnes - S. epidermidis biofilm model. The biofilm formation and growth of mixed culture of P. acnes and S. epidermidis was significantly slowed at 12.5 mg/ml of NAC. NAC also has a higher disruptive effect on both mature M. smegmatis and mixed P. acnes - S. epidermidis biofilm. Thus, NAC appears to be a promising, non-antibiotic alternative to prevent biofilm-associated infections.}, } @article {pmid28236355, year = {2017}, author = {Buijssen, KJDA and Oosterhof, JJH and Basil, L and Waters, M and Duits, MA and Busscher, HJ and van der Mei, HC and van der Laan, BFAM}, title = {Influence of surface roughness on silicone rubber voice prostheses on in vitro biofilm formation and clinical lifetime in laryngectomised patients.}, journal = {Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery}, volume = {42}, number = {6}, pages = {1235-1240}, doi = {10.1111/coa.12856}, pmid = {28236355}, issn = {1749-4486}, mesh = {Aged ; Aged, 80 and over ; *Biofilms ; Glottis ; Humans ; Hypopharyngeal Neoplasms/surgery ; Laryngeal Neoplasms/surgery ; Laryngectomy ; *Larynx, Artificial ; Male ; Middle Aged ; *Prosthesis Design ; Prosthesis Failure ; *Silicone Elastomers ; Surface Properties ; }, abstract = {OBJECTIVES: Evaluation of the influence of a smooth surface moulding technique of silicone rubber indwelling voice prostheses on in vitro biofilm formation and analysis of the clinical in situ lifetime.

DESIGN: Biofilm formation on smooth and Groningen ultra low resistance (URL) prostheses was studied in an artificial throat model. The clinical lifetime of smooth voice prostheses was compared to the previous lifetime of URL by counting the number of replacements in a consecutive 6-month period in the same patient.

PARTICIPANTS: Eleven laryngectomised patients in follow-up who required frequent replacement of their voice prostheses.

SETTINGS: Tertiary University Medical Center.

RESULTS: Use of a smoother mould and less viscous silicone rubber yielded a decrease in surface roughness from 46 to 8 nm and was accompanied by a 40% reduction in the prevalence of bacteria and yeast in in vitro formed biofilms. Clinically, the lifetime was significantly (P<.005) increased by a factor of 2.1.

CONCLUSIONS: This combined in vitro and clinical study suggests that the choice of material and in particular its surface finishing may be determining factors with respect to the clinical lifetime of silicone rubber implants and devices failing due to biofilm formation.}, } @article {pmid28234834, year = {2017}, author = {Hunter, JG}, title = {Discussion: The Role of Bacterial Biofilm in Adverse Soft-Tissue Filler Reactions: A Combined Laboratory and Clinical Study.}, journal = {Plastic and reconstructive surgery}, volume = {139}, number = {3}, pages = {622-623}, doi = {10.1097/PRS.0000000000003068}, pmid = {28234834}, issn = {1529-4242}, mesh = {Biocompatible Materials ; *Biofilms ; *Cosmetic Techniques ; Humans ; Hyaluronic Acid ; }, } @article {pmid28234833, year = {2017}, author = {Saththianathan, M and Johani, K and Taylor, A and Hu, H and Vickery, K and Callan, P and Deva, AK}, title = {The Role of Bacterial Biofilm in Adverse Soft-Tissue Filler Reactions: A Combined Laboratory and Clinical Study.}, journal = {Plastic and reconstructive surgery}, volume = {139}, number = {3}, pages = {613-621}, doi = {10.1097/PRS.0000000000003067}, pmid = {28234833}, issn = {1529-4242}, mesh = {Acrylic Resins/*adverse effects ; *Biofilms ; Dermal Fillers/*adverse effects ; Female ; Humans ; Hyaluronic Acid/*adverse effects ; Male ; Middle Aged ; Polyesters/*adverse effects ; Soft Tissue Infections/*etiology ; Staphylococcal Infections/*etiology ; Staphylococcus epidermidis/*physiology ; Tissue Culture Techniques ; }, abstract = {BACKGROUND: The development of chronic nodules and granulomatous inflammation after filler injections has been attributed to bacterial biofilm infection. The authors aimed to investigate the relationship between filler and bacterial biofilm using a combined in vitro and in vivo study.

METHODS: In vitro assays to investigate the ability of filler materials to support the growth of Staphylococcus epidermidis biofilm and the effect of multiple needle passes through a biofilm-contaminated surface were designed. Analysis of clinical biopsy specimens from patients presenting with chronic granulomas following filler administration using a number of laboratory tests for biofilm was performed.

RESULTS: All fillers (i.e., hyaluronic acid, polyacrylamide gel, and poly-L-lactic acid) supported the growth of S. epidermidis biofilm in vitro. Multiple needle passes through a biofilm-contaminated surface resulted in significantly increased contamination of filler material by a factor of 10,000 (p < 0.001). Six clinical samples from five patients all demonstrated bacterial biofilm. The mean number of bacteria was found to be 2.2 × 10 bacteria/mg tissue (range, 5.6 × 10 to 3.7 × 10 bacteria/mg tissue). Microbiome analysis detected a predominance of Pseudomonas, Staphylococcus, and Propionibacterium as present in these samples.

CONCLUSIONS: Filler material can support the growth of bacterial biofilm in vitro. Multiple needle passes can significantly increase the risk of filler contamination. Biofilm appears to be associated with high numbers in clinical samples of patients presenting with chronic granulomatous inflammation. Strategies to reduce the risk of bacterial contamination need to be further studied and translated into clinical practice.

Therapeutic, V.}, } @article {pmid28233286, year = {2017}, author = {Khan, ST and Khan, M and Ahmad, J and Wahab, R and Abd-Elkader, OH and Musarrat, J and Alkhathlan, HZ and Al-Kedhairy, AA}, title = {Thymol and carvacrol induce autolysis, stress, growth inhibition and reduce the biofilm formation by Streptococcus mutans.}, journal = {AMB Express}, volume = {7}, number = {1}, pages = {49}, pmid = {28233286}, issn = {2191-0855}, abstract = {Organic compounds from plants are an attractive alternative to conventional antimicrobial agents. Therefore, two compounds namely M-1 and M-2 were purified from Origanum vulgare L. and were identified as carvacrol and thymol, respectively. Antimicrobial and antibiofilm activities of these compounds along with chlorhexidine digluconate using various assays was determined against dental caries causing bacteria Streptococcus mutans. The IC50 values of carvacrol (M-1) and thymol (M-2) against S. mutans were 65 and 54 µg/ml, respectively. Live and dead staining and the MTT assays reveal that a concentration of 100 µg/ml of these compounds reduced the viability and the metabolic activity of S. mutans by more than 50%. Biofilm formation on the surface of polystyrene plates was significantly reduced by M-1 and M-2 at 100 µg/ml as observed under scanning electron microscope and by colorimetric assay. These results were in agreement with RT-PCR studies. Wherein exposure to 25 µg/ml of M-1 and M-2 showed a 2.2 and 2.4-fold increase in Autolysin gene (AtlE) expression level, respectively. While an increase of 1.3 and 1.4 fold was observed in the super oxide dismutase gene (sodA) activity with the same concentrations of M-1 and M-2, respectively. An increase in the ymcA gene and a decrease in the gtfB gene expression levels was observed following the treatment with M-1 and M-2. These results strongly suggest that carvacrol and thymol isolated from O. vulgare L. exhibit good bactericidal and antibiofilm activity against S. mutans and can be used as a green alternative to control dental caries.}, } @article {pmid28229593, year = {2017}, author = {Doll, K and Fadeeva, E and Schaeske, J and Ehmke, T and Winkel, A and Heisterkamp, A and Chichkov, BN and Stiesch, M and Stumpp, NS}, title = {Development of Laser-Structured Liquid-Infused Titanium with Strong Biofilm-Repellent Properties.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {11}, pages = {9359-9368}, doi = {10.1021/acsami.6b16159}, pmid = {28229593}, issn = {1944-8252}, mesh = {Bacterial Adhesion ; *Biofilms ; Humans ; Surface Properties ; Titanium ; }, abstract = {Medical implants are commonly used in modern medicine but still harbor the risk of microbial infections caused by bacterial biofilms. As their retrospective treatment is difficult, there is a need for biomedical materials that inhibit bacterial colonization from the start without using antibacterial agents, as these can promote resistance development. The promising concept of slippery liquid-infused porous surfaces (SLIPS) possesses enormous potential for this purpose. In the present study, this principle was applied to titanium, a common material in implantology, and its biofilm-repellent properties were demonstrated. To simplify prospective approval of the medical device and to avoid chemical contamination, surface structuring was performed by ultrashort pulsed laser ablation. Four different structures (hierarchical micro- and nanosized spikes, microsized grooves, nanosized ripples, and unstructured surfaces) and five infusing perfluoropolyethers of different viscosities were screened; the best results were obtained with the biomimetic, hierarchical spike structure combined with lubricants of medium viscosities (20-60 cSt at 37 °C, 143 AZ, and GPL 104). The surfaces exhibited extremely low contact angle hysteresis, as is typical for liquid-infused materials and a reliable 100-fold reduction of human oral pathogen Streptococcus oralis biofilms. This characteristic was maintained after exposure to shear forces and gravity. The titanium SLIPS also inhibited adherence of human fibroblasts and osteoblasts. Toxicity tests supported the explanation that solely the surface's repellent properties are responsible for the vigorous prevention of the adhesion of bacteria and cells. This use of physically structured and liquid-infused titanium to avoid bioadhesion should support the prevention of bacterial implant-associated infections without the use of antibacterial agents.}, } @article {pmid28225903, year = {2017}, author = {Sued, BP and Pereira, PM and Faria, YV and Ramos, JN and Binatti, VB and Santos, KR and Seabra, SH and Hirata, R and Vieira, VV and Mattos-Guaraldi, AL and Pereira, JA}, title = {Sphygmomanometers and thermometers as potential fomites of Staphylococcus haemolyticus: biofilm formation in the presence of antibiotics.}, journal = {Memorias do Instituto Oswaldo Cruz}, volume = {112}, number = {3}, pages = {188-195}, pmid = {28225903}, issn = {1678-8060}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Cross Infection/microbiology/transmission ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Fomites/*microbiology ; Humans ; Microbial Sensitivity Tests ; Oxacillin/pharmacology ; Sphygmomanometers/*microbiology ; Staphylococcal Infections/microbiology/transmission ; Staphylococcus haemolyticus/drug effects/isolation & purification/*physiology ; Thermometers/*microbiology ; Vancomycin/pharmacology ; }, abstract = {BACKGROUND: The association between Staphylococcus haemolyticus and severe nosocomial infections is increasing. However, the extent to which fomites contribute to the dissemination of this pathogen through patients and hospital wards remains unknown.

OBJECTIVES: In the present study, sphygmomanometers and thermometers were evaluated as potential fomites of oxacillin-resistant S. haemolyticus (ORSH). The influence of oxacillin and vancomycin on biofilm formation by ORSH strains isolated from fomites was also investigated.

METHODS: The presence of ORSH on swabs taken from fomite surfaces in a Brazilian hospital was assessed using standard microbiological procedures. Antibiotic susceptibility profiles were determined by the disk diffusion method, and clonal distribution was assessed in pulsed-field gel electrophoresis (PFGE) assays. Minimum inhibitory concentrations (MICs) of oxacillin and vancomycin were evaluated via the broth microdilution method. Polymerase chain reaction (PCR) assays were performed to detect the mecA and icaAD genes. ORSH strains grown in media containing 1/4 MIC of vancomycin or oxacillin were investigated for slime production and biofilm formation on glass, polystyrene and polyurethane catheter surfaces.

FINDINGS: ORSH strains comprising five distinct PFGE types were isolated from sphygmomanometers (n = 5) and a thermometer (n = 1) used in intensive care units and surgical wards. ORSH strains isolated from fomites showed susceptibility to only linezolid and vancomycin and were characterised as multi-drug resistant (MDR). Slime production, biofilm formation and the survival of sessile bacteria differed and were independent of the presence of the icaAD and mecA genes, PFGE type and subtype. Vancomycin and oxacillin did not inhibit biofilm formation by vancomycin-susceptible ORSH strains on abiotic surfaces, including on the catheter surface. Enhanced biofilm formation was observed in some situations. Moreover, a sub-lethal dose of vancomycin induced biofilm formation by an ORSH strain on polystyrene.

MAIN CONCLUSIONS: Sphygmomanometers and thermometers are fomites for the transmission of ORSH. A sub-lethal dose of vancomycin may favor biofilm formation by ORSH on fomites and catheter surfaces.}, } @article {pmid28223375, year = {2017}, author = {Larkin, E and Hager, C and Chandra, J and Mukherjee, PK and Retuerto, M and Salem, I and Long, L and Isham, N and Kovanda, L and Borroto-Esoda, K and Wring, S and Angulo, D and Ghannoum, M}, title = {The Emerging Pathogen Candida auris: Growth Phenotype, Virulence Factors, Activity of Antifungals, and Effect of SCY-078, a Novel Glucan Synthesis Inhibitor, on Growth Morphology and Biofilm Formation.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {5}, pages = {}, pmid = {28223375}, issn = {1098-6596}, support = {P30 AR039750/AR/NIAMS NIH HHS/United States ; R01 DE024228/DE/NIDCR NIH HHS/United States ; }, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/growth & development/isolation & purification/*pathogenicity ; Candida albicans/growth & development/pathogenicity ; Candidiasis/drug therapy/microbiology ; Cell Adhesion ; Cell Division/drug effects ; Drug Resistance, Multiple, Fungal ; Fluconazole/pharmacology ; Glucans/biosynthesis ; Glycosides/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Peptide Hydrolases/biosynthesis ; Phospholipases/biosynthesis ; Triterpenes/*pharmacology ; Virulence Factors ; }, abstract = {Candidaauris, a new multidrug-resistant Candida spp. which is associated with invasive infection and high rates of mortality, has recently emerged. Here, we determined the virulence factors (germination, adherence, biofilm formation, phospholipase and proteinase production) of 16 C. auris isolates and their susceptibilities to 11 drugs belonging to different antifungal classes, including a novel orally bioavailable 1,3-β-d-glucan synthesis inhibitor (SCY-078). We also examined the effect of SCY-078 on the growth, ultrastructure, and biofilm-forming abilities of C. auris Our data showed that while the tested strains did not germinate, they did produce phospholipase and proteinase in a strain-dependent manner and had a significantly reduced ability to adhere and form biofilms compared to that of Candida albicans (P = 0.01). C. auris isolates demonstrated reduced susceptibility to fluconazole and amphotericin B, while, in general, they were susceptible to the remaining drugs tested. SCY-078 had an MIC90 of 1 mg/liter against C. auris and caused complete inhibition of the growth of C. auris and C. albicans Scanning electron microscopy analysis showed that SCY-078 interrupted C. auris cell division, with the organism forming abnormal fused fungal cells. Additionally, SCY-078 possessed potent antibiofilm activity, wherein treated biofilms demonstrated significantly reduced metabolic activity and a significantly reduced thickness compared to the untreated control (P < 0.05 for both comparisons). Our study shows that C. auris expresses several virulence determinants (albeit to a lesser extent than C. albicans) and is resistant to fluconazole and amphotericin B. SCY-078, the new orally bioavailable antifungal, had potent antifungal/antibiofilm activity against C. auris, indicating that further evaluation of this antifungal is warranted.}, } @article {pmid28221917, year = {2016}, author = {Wang, R and Luedtke, BE and Bosilevac, JM and Schmidt, JW and Kalchayanand, N and Arthur, TM}, title = {Escherichia coli O157:H7 Strains Isolated from High-Event Period Beef Contamination Have Strong Biofilm-Forming Ability and Low Sanitizer Susceptibility, Which Are Associated with High pO157 Plasmid Copy Number.}, journal = {Journal of food protection}, volume = {79}, number = {11}, pages = {1875-1883}, doi = {10.4315/0362-028X.JFP-16-113}, pmid = {28221917}, issn = {1944-9097}, mesh = {Animals ; *Biofilms ; Cattle ; Escherichia coli O157/*isolation & purification ; Meat/microbiology ; Plasmids ; Red Meat ; }, abstract = {In the meat industry, a high-event period (HEP) is defined as a time period when beef processing establishments experience an increased occurrence of product contamination by Escherichia coli O157:H7. Our previous studies suggested that bacterial biofilm formation and sanitizer resistance might contribute to HEPs. We conducted the present study to further characterize E. coli O157:H7 strains isolated during HEPs for their potential to cause contamination and to investigate the genetic basis for their strong biofilm-forming ability and high sanitizer resistance. Our results show that, compared with the E. coli O157:H7 diversity control panel strains, the HEP strains had a significantly higher biofilm-forming ability on contact surfaces and a lower susceptibility to common sanitizers. No difference in the presence of disinfectant-resistant genes or the prevalence of antibiotic resistance was observed between the HEP and control strains. However, the HEP strains retained significantly higher copy numbers of the pO157 plasmid. A positive correlation was observed among a strain's high plasmid copy number, strong biofilm-forming ability, low sanitizer susceptibility, and high survival and recovery capability after sanitization, suggesting that these specific phenotypes could be either directly correlated to gene expression on the pO157 plasmid or indirectly regulated via chromosomal gene expression influenced by the presence of the plasmid. Our data highlight the potential risk of biofilm formation and sanitizer resistance in HEP contamination by E. coli O157:H7, and our results call for increased attention to proper and effective sanitization practices in meat processing facilities.}, } @article {pmid28221135, year = {2017}, author = {Mashruwala, AA and Guchte, AV and Boyd, JM}, title = {Impaired respiration elicits SrrAB-dependent programmed cell lysis and biofilm formation in Staphylococcus aureus.}, journal = {eLife}, volume = {6}, number = {}, pages = {}, pmid = {28221135}, issn = {2050-084X}, mesh = {Bacterial Proteins/*metabolism ; *Bacteriolysis ; Biofilms/*growth & development ; *Energy Metabolism ; Gene Expression Regulation, Bacterial ; Models, Biological ; Oxidation-Reduction ; Oxygen/*metabolism ; Repressor Proteins/*metabolism ; Staphylococcus aureus/growth & development/metabolism/*physiology ; Vitamin K 2/metabolism ; }, abstract = {Biofilms are communities of microorganisms attached to a surface or each other. Biofilm-associated cells are the etiologic agents of recurrent Staphylococcus aureus infections. Infected human tissues are hypoxic or anoxic. S. aureus increases biofilm formation in response to hypoxia, but how this occurs is unknown. In the current study we report that oxygen influences biofilm formation in its capacity as a terminal electron acceptor for cellular respiration. Genetic, physiological, or chemical inhibition of respiratory processes elicited increased biofilm formation. Impaired respiration led to increased cell lysis via divergent regulation of two processes: increased expression of the AtlA murein hydrolase and decreased expression of wall-teichoic acids. The AltA-dependent release of cytosolic DNA contributed to increased biofilm formation. Further, cell lysis and biofilm formation were governed by the SrrAB two-component regulatory system. Data presented support a model wherein SrrAB-dependent biofilm formation occurs in response to the accumulation of reduced menaquinone.}, } @article {pmid28218002, year = {2017}, author = {Konstantinović, N and Ćirković, I and Đukić, S and Marić, V and Božić, DD}, title = {Biofilm formation of Achromobacter xylosoxidans on contact lens.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {64}, number = {3}, pages = {293-300}, doi = {10.1556/030.64.2017.005}, pmid = {28218002}, issn = {1217-8950}, mesh = {Achromobacter denitrificans/*physiology ; Biofilms/*growth & development ; Contact Lenses, Hydrophilic/*microbiology ; Surface Properties ; }, abstract = {Achromobacter spp. may contaminate lenses, lens cases, and contact lens solutions and cause ocular infections. The aim of this study was to investigate the possibility of isolated strain of Achromobacter xylosoxidans to form biofilm on the surface of soft contact lenses (CL), to quantify the production of the formed biofilm, and compare it with the reference strains (Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae). Bacterial strain isolated from one contact lens case was identified as A. xylosoxidans using Vitek2 Automated System. Biofilm forming capacity of isolated strain of A. xylosoxidans and reference strains of P. aeruginosa, S. aureus, and H. influenzae on soft CL were analyzed by commonly used microtitre plate method. Our results showed that isolated strain of A. xylosoxidans was capable to form biofilm on the surface of soft contact lens. A. xylosoxidans was strong biofilm producer while all examined reference strains were moderate biofilm producers. A. xylosoxidans appears to be superior biofilm producer on soft CL compared to reference strains.}, } @article {pmid28217816, year = {2017}, author = {Paulone, S and Malavasi, G and Ardizzoni, A and Orsi, CF and Peppoloni, S and Neglia, RG and Blasi, E}, title = {Candida albicans survival, growth and biofilm formation are differently affected by mouthwashes: an in vitro study.}, journal = {The new microbiologica}, volume = {40}, number = {1}, pages = {45-52}, pmid = {28217816}, issn = {1121-7138}, mesh = {Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*physiology ; Chlorhexidine/analogs & derivatives/chemistry/pharmacology ; Humans ; *Mouthwashes ; Sodium Fluoride/chemistry/pharmacology ; }, abstract = {Candida albicans is the most common cause of oral mycoses. The aim of the present study was to investigate in vitro the susceptibility of C. albicans to mouthwashes, in terms of growth, survival and biofilm formation. Candida albicans, laboratory strain SC5314, and 7 commercial mouthwashes were employed: 3 with 0.2% chlorhexidine digluconate; 1 with 0.06% chlorhexidine digluconate and 250 ppm F- sodium fluoride; 3 with fluorine-containing molecules. None of the mouthwashes contained ethanol in their formulations. The anti-Candida effects of the mouthwashes were assessed by disk diffusion, crystal violet and XTT assays. By using five protocols combining different dilutions and contact times the mouthwashes were tested against: 1) C. albicans growth; 2) biofilm formation; 3) survival of fungal cells in early, developing and mature Candida biofilm. Chlorhexidine digluconate-containing mouthwashes consistently exhibited the highest anti-Candida activity, irrespective of the protocols employed. Fungal growth, biofilm formation and survival of Candida cells within biofilm were impaired, the effects strictly depending on both the dilution employed and the time of contact. These in vitro studies provide evidence that mouthwashes exert anti-Candida activity against both planktonic and biofilm fungal structures, but to a different extent depending on their composition. This suggests special caution in the choice of mouthwashes for oral hygiene, whether aimed at prevention or treatment of oral candidiasis.}, } @article {pmid28216269, year = {2017}, author = {Jacobs, JC and Troxel, A and Ehrlich, Y and Spolnik, K and Bringas, JS and Gregory, RL and Yassen, GH}, title = {Antibacterial Effects of Antimicrobials Used in Regenerative Endodontics against Biofilm Bacteria Obtained from Mature and Immature Teeth with Necrotic Pulps.}, journal = {Journal of endodontics}, volume = {43}, number = {4}, pages = {575-579}, doi = {10.1016/j.joen.2016.12.014}, pmid = {28216269}, issn = {1878-3554}, mesh = {Adolescent ; Anti-Infective Agents/*therapeutic use ; Biofilms/*drug effects ; Child ; Dental Pulp Necrosis/*microbiology ; Dentin/microbiology ; Humans ; Root Canal Irrigants/therapeutic use ; Root Canal Preparation/*methods ; }, abstract = {INTRODUCTION: We investigated the direct and residual antibacterial effects of intracanal antimicrobials against bacterial biofilms obtained from infected mature and immature teeth with necrotic pulps.

METHODS: Sterile dentin slabs (n = 100) were inoculated with bacterial biofilms obtained from root canals of an immature or a mature tooth with pulpal necrosis and incubated anaerobically for 3 weeks (n = 50 per biofilm). Dentin infected with each type of biofilm received 1 week of treatment with 1 or 5 mg/mL double antibiotic paste (DAP) in methylcellulose hydrogels, calcium hydroxide, or placebo paste or received no treatment (n = 10). The pastes were removed, and biofilm disruption assays were performed. Additional dentin slabs (n = 100) were pretreated with the same treatments (n = 20). The pastes were rinsed off, and the samples were immersed in phosphate-buffered saline for 1 week. Thereafter, samples from the treatment groups were infected with bacterial biofilm from both clinical sources mentioned earlier (n = 10 per biofilm) and incubated anaerobically for 3 weeks before conducting biofilm disruption assays. Uninfected dentin slabs were used for both antibacterial experiments as negative control groups (n = 20).

RESULTS: All antimicrobials showed significant direct antibacterial effects regardless of the biofilm source. Dentin pretreated with 5 mg/mL DAP provided significantly higher residual antibacterial effects in comparison with all other groups regardless of the source of biofilm. Dentin pretreated with calcium hydroxide did not show any residual antibacterial effects.

CONCLUSIONS: Tested antimicrobials showed significant direct antibacterial effects. Only 5 mg/mL DAP exhibited significant residual antibacterial effects against bacterial biofilms from an infected root canal of an immature tooth.}, } @article {pmid28214733, year = {2017}, author = {Santos, TB and Vieira, AA and Paula, LO and Santos, ED and Radi, PA and Khouri, S and Maciel, HS and Pessoa, RS and Vieira, L}, title = {Flexible camphor diamond-like carbon coating on polyurethane to prevent Candida albicans biofilm growth.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {68}, number = {}, pages = {239-246}, doi = {10.1016/j.jmbbm.2017.02.013}, pmid = {28214733}, issn = {1878-0180}, mesh = {Biofilms/*drug effects ; Camphor/*chemistry ; Candida albicans/*drug effects ; Carbon/*chemistry ; Coated Materials, Biocompatible/*chemistry ; Diamond ; Materials Testing ; Polyurethanes/*chemistry ; Surface Properties ; }, abstract = {Camphor was incorporated in diamond-like carbon (DLC) films to prevent the Candida albicans yeasts fouling on polyurethane substrates, which is a material commonly used for catheter manufacturing. The camphor:DLC and DLC film for this investigation was produced by plasma enhanced chemical vapor deposition (PECVD), using an apparatus based on the flash evaporation of organic liquid (hexane) containing diluted camphor for camphor:DLC and hexane/methane, mixture for DLC films. The film was deposited at a low temperature of less than 25°C. We obtained very adherent camphor:DLC and DLC films that accompanied the substrate flexibility without delamination. The adherence of camphor:DLC and DLC films on polyurethane segments were evaluated by scratching test and bending polyurethane segments at 180°. The polyurethane samples, with and without camphor:DLC and DLC films were characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, and optical profilometry. Candida albicans biofilm formation on polyurethane, with and without camphor:DLC and DLC, was assessed. The camphor:DLC and DLC films reduced the biofilm growth by 99.0% and 91.0% of Candida albicans, respectively, compared to bare polyurethane. These results open the doors to studies of functionalized DLC coatings with biofilm inhibition properties used in the production of catheters or other biomedical applications.}, } @article {pmid28214190, year = {2017}, author = {Torlak, E and Korkut, E and Uncu, AT and Şener, Y}, title = {Biofilm formation by Staphylococcus aureus isolates from a dental clinic in Konya, Turkey.}, journal = {Journal of infection and public health}, volume = {10}, number = {6}, pages = {809-813}, doi = {10.1016/j.jiph.2017.01.004}, pmid = {28214190}, issn = {1876-035X}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; *Dental Clinics ; *Environmental Microbiology ; Humans ; Polymerase Chain Reaction ; Staphylococcus aureus/genetics/*isolation & purification/*physiology ; Turkey ; Virulence Factors/*genetics ; }, abstract = {The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes' detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.}, } @article {pmid28213809, year = {2017}, author = {Brunetti, G and Visconti, V and Ghezzi, MC and Giordano, A and Raponi, G}, title = {The Correlation Between Biofilm Production and Catheter-Related Bloodstream Infections Sustained by Candida. A Case Control Study.}, journal = {Advances in experimental medicine and biology}, volume = {973}, number = {}, pages = {89-98}, doi = {10.1007/5584_2016_196}, pmid = {28213809}, issn = {0065-2598}, mesh = {Bacteremia/*microbiology ; *Biofilms ; Blood/microbiology ; Candida/genetics/*isolation & purification/*physiology ; Case-Control Studies ; Catheter-Related Infections/blood/*microbiology ; Humans ; }, abstract = {Biofilm forming capacity of yeasts colonizing the intravenous devices is considered a key factor involved in the pathogenesis of Candida catheter-related bloodstream infections (CCRBSI). The biofilm production of strains of Candida spp. isolated both from the CVC and from the blood of patients with CCRBSI was compared to that of strains isolated from patients not having CCRBSI. Results, expressed in terms of Biofilm Index (BI), revealed that biofilm-producing strains were isolated in the CCRBSI group with a frequency significantly higher than in the non-CCRBSI group (χ[2] = 4.25, p = 0.03). The species more frequently cultured was C. parapsilosis complex (including C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis). When this species was isolated from the CVC tip cultures of the CCRBSI group it showed BIs significantly (p = 0.05) higher than those found in the non-CCRBSI group. All the strains of C. tropicalis isolated from the CCRBSI group produced biofilm. Instead most of the isolates of C. glabrata were non-producers. The cumulative BI of non-albicans Candida strains isolated from CCRBSI patients was significantly higher than that of non-albicans strains cultured from patients non-CCRBSI (χ[2] = 6.91; p = 0.008). C. albicans was a biofilm producer both in the CCRBSI and in the non-CCRBSI group. When isolated from the blood it showed enhanced biofilm production in the CCRBSI group only, while when colonizing the CVC it displayed high BIs both in the CCRBSI group and in non-CCRBSI group. Our data seem to indicate that the biofilm production capacity should be considered in the clinical management of CCRBSI.}, } @article {pmid28213335, year = {2017}, author = {Ooi, GTH and Escola Casas, M and Andersen, HR and Bester, K}, title = {Transformation products of clindamycin in moving bed biofilm reactor (MBBR).}, journal = {Water research}, volume = {113}, number = {}, pages = {139-148}, doi = {10.1016/j.watres.2017.01.058}, pmid = {28213335}, issn = {1879-2448}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Clindamycin ; Sewage/microbiology ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {Clindamycin is widely prescribed for its ability to treat a number of common bacterial infections. Thus, clindamycin enters wastewater via human excretion or disposal of unused medication and widespread detection of pharmaceuticals in rivers proves the insufficiency of conventional wastewater treatment plants in removing clindamycin. Recently, it has been discovered that attached biofilm reactors, e.g., moving bed biofilm reactors (MBBRs) obtain a higher removal of pharmaceuticals than conventional sludge wastewater treatment plants. Therefore, this study investigated the capability of MBBRs applied in the effluent of conventional wastewater treatment plants to remove clindamycin. First, a batch experiment was executed with a high initial concentration of clindamycin to identify the transformation products. It was shown that clindamycin can be removed from wastewater by MBBR and the treatment process converts clindamycin into the, possibly persistent, products clindamycin sulfoxide and N-desmethyl clindamycin as well as 3 other mono-oxygenated products. Subsequently, the removal kinetics of clindamycin and the formation of the two identified products were investigated in batch experiments using MBBR carriers from polishing and nitrifying reactors. Additionally, the presence of these two metabolites in biofilm-free wastewater effluent was studied. The nitrifying biofilm reactor had a higher biological activity with k-value of 0.1813 h[-1] than the reactor with polishing biofilm (k = 0.0161 h[-1]) which again has a much higher biological activity for removal of clindamycin than of the suspended bacteria (biofilm-free control). Clindamycin sulfoxide was the main transformation product which was found in concentrations exceeding 10% of the initial clindamycin concentration after 1 day of MBBR treatment. Thus, MBBRs should not necessarily be considered as reactors mineralizing clindamycin as they perform transformation reactions at least to some extent.}, } @article {pmid28213334, year = {2017}, author = {Dryden, MS and Cooke, J and Salib, RJ and Holding, RE and Biggs, T and Salamat, AA and Allan, RN and Newby, RS and Halstead, F and Oppenheim, B and Hall, T and Cox, SC and Grover, LM and Al-Hindi, Z and Novak-Frazer, L and Richardson, MD}, title = {Reactive oxygen: A novel antimicrobial mechanism for targeting biofilm-associated infection.}, journal = {Journal of global antimicrobial resistance}, volume = {8}, number = {}, pages = {186-191}, doi = {10.1016/j.jgar.2016.12.006}, pmid = {28213334}, issn = {2213-7173}, mesh = {Administration, Topical ; Animals ; Anti-Infective Agents, Local/*therapeutic use ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Drug Evaluation, Preclinical ; Fungi/drug effects ; Humans ; Reactive Oxygen Species/*therapeutic use ; Wound Infection/*drug therapy ; }, abstract = {Reactive oxygen species (ROS) is a novel therapeutic strategy for topical or local application to wounds, mucosa or internal structures where there may be heavy bacterial bioburden with biofilm and chronic inflammation. Bacterial biofilms are a significant problem in clinical settings owing to their increased tolerance towards conventionally prescribed antibiotics and their propensity for selection of further antibacterial resistance. There is therefore a pressing need for the development of alternative therapeutic strategies that can improve antibiotic efficacy towards biofilms. ROS has been successful in treating chronic wounds and in clearing multidrug-resistant organisms, including methicillin-resistant Staphylococcus aureus (MRSA), and carbapenemase-producing isolates from wounds and vascular line sites. There is significant antifungal activity of ROS against planktonic and biofilm forms. Nebulised ROS has been evaluated in limited subjects to assess reductions in bioburden in chronically colonised respiratory tracts. The antibiofilm activity of ROS could have great implications for the treatment of a variety of persistent respiratory conditions. Use of ROS on internal prosthetic devices shows promise. A variety of novel delivery mechanisms are being developed to apply ROS activity to different anatomical sites.}, } @article {pmid28213285, year = {2017}, author = {Li, Q and Sand, W}, title = {Mechanical and chemical studies on EPS from Sulfobacillus thermosulfidooxidans: from planktonic to biofilm cells.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {153}, number = {}, pages = {34-40}, doi = {10.1016/j.colsurfb.2017.02.009}, pmid = {28213285}, issn = {1873-4367}, mesh = {*Biofilms ; Microscopy, Atomic Force ; Particle Size ; *Plankton ; Polymers/*chemistry ; Sulfolobaceae/*chemistry/metabolism ; Surface Properties ; }, abstract = {Bacteria attach to minerals and form biofilms, which can initiate and enhance bioleaching. Extracellular polymeric substances (EPS) play a crucial role during the whole process. Little is known how the cell surface/EPS mechanically and chemically respond to transformation from planktonic to biofilm cells. In this study the attachment and biofilm formation by Sulfobacillus thermosulfidooxidans were followed during pyrite leaching. Adhesiveness and stiffness of the cell/biofilm and the pyrite surface were checked by atomic force microscopy (AFM) in force mapping mode under real living conditions. The EPS components were analysed by colorimetry, fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The results indicate that slimy and soft EPS heterogeneously accumulated in the biofilms and on the surface of pyrite to induce bacterial adhesion and form robust biofilms. After attaching to the pyrite surface, the cells started to change the components of their EPS. Huge amounts of humic substances were detected in the biofilm EPS.}, } @article {pmid28213018, year = {2017}, author = {Fu, Y and Deering, AJ and Bhunia, AK and Yao, Y}, title = {Pathogen biofilm formation on cantaloupe surface and its impact on the antibacterial effect of lauroyl arginate ethyl.}, journal = {Food microbiology}, volume = {64}, number = {}, pages = {139-144}, doi = {10.1016/j.fm.2016.12.020}, pmid = {28213018}, issn = {1095-9998}, mesh = {Anti-Bacterial Agents/*pharmacology ; Arginine/*analogs & derivatives/pharmacology ; Bacterial Load ; Biofilms/drug effects/*growth & development ; Cucumis melo/*microbiology ; Listeria monocytogenes/drug effects/pathogenicity/physiology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Salmonella enterica/drug effects/pathogenicity/physiology/ultrastructure ; Salmonella typhimurium/drug effects/pathogenicity/physiology ; }, abstract = {Pathogen biofilm at fruit surface may pose a particular risk to food safety. In this study, the biofilms of Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium ATCC 13311 on cantaloupe fruit surface were visualized, and the resistance of biofilms against lauroyl arginate ethyl (LAE, an antibacterial compound) was evaluated. Each bacterium was inoculated on isolated cantaloupe rind surfaces at 10[5]-10[6] CFU/cm[2] and after incubation for 2, 12, 24, and 48 h, the surfaces were imaged using cryo-scanning electron microscopy (Cryo-SEM). The images showed that both pathogens formed biofilms on rind surfaces, with S. Typhimurium forming biofilm in 12 h and L. monocytogenes cells starting to aggregate in 2 h. For the inoculated rind surfaces treated with LAE, the cell counts were affected by both the incubation time and LAE concentration. For rind surface with 2 h incubation of S. Typhimurium, 400 and 800 μg/mL LAE was able to achieve >2.00 log reduction; however, 12 h incubation required 1600 and 2000 μg/mL LAE for >2.00 log reduction. In contrast, even the highest LAE concentration (2000 μg/mL) was unable to cause 1.00 log reduction for L. monocytogenes regardless the incubation time applied. The results showed that the biofilms of both bacteria substantially reduced LAE efficacy, and that the biofilm of L. monocytogenes was more resistant than that of S. Typhimurium.}, } @article {pmid28212980, year = {2017}, author = {Hahnel, S and Ionescu, AC and Cazzaniga, G and Ottobelli, M and Brambilla, E}, title = {Biofilm formation and release of fluoride from dental restorative materials in relation to their surface properties.}, journal = {Journal of dentistry}, volume = {60}, number = {}, pages = {14-24}, doi = {10.1016/j.jdent.2017.02.005}, pmid = {28212980}, issn = {1879-176X}, mesh = {Biofilms/*drug effects/*growth & development ; Cariostatic Agents/*chemistry ; Composite Resins/chemistry ; Dental Enamel/microbiology ; Dental Materials/*chemistry ; Dental Pellicle ; Fluorides/*chemistry ; Glass Ionomer Cements/*chemistry ; Humans ; Light-Curing of Dental Adhesives ; Materials Testing ; Streptococcus mutans/drug effects/physiology ; Surface Properties ; Time Factors ; }, abstract = {OBJECTIVES: To elucidate the impact of surface properties and the release of fluoride from different glass ionomer cements on biofilm formation.

METHODS: Standardized specimens manufactured from various classes of glass ionomer cements (GICs), a resin-based composite (RBC), and human enamel were subjected to surface analyses. Subsequent to simulation of salivary pellicle formation, Streptococcus mutans biofilm formation was initiated using a drip flow reactor for 48h and 96h. Biofilms were characterized by determining viable bacterial biomass and 3D biofilm architecture using SEM and CLSM; the release of fluoride from the specimens was measured using the ion selective micro method in dependence on various experimental conditions (incubation with sterile broth/bacteria/acid).

RESULTS: Surface properties and biofilm formation correlated poorly, while the release of fluoride correlated well with viable streptococcal biomass and SEM/CLSM analyses. For all investigated materials, biofilm formation was lower than on enamel. The release of fluoride showed a significant dependency on the experimental conditions applied; the presence of biofilms reduced fluoride release in comparison to sterile incubation conditions.

CONCLUSIONS: Within the limitations of a laboratory study, the results suggest that biofilm formation on GICs cannot be easily predicted as a function of substratum surface parameters. The release of fluoride from glass ionomer cements contributes to control biofilm formation particularly in its early phases.

CLINICAL SIGNIFICANCE: Glass ionomer cements can actively control microbial biofilm formation, while biofilms modulate the release of fluoride from GIC materials.}, } @article {pmid28212517, year = {2017}, author = {Sai Saraswathi, V and Kamarudheen, N and BhaskaraRao, KV and Santhakumar, K}, title = {Phytoremediation of dyes using Lagerstroemia speciosa mediated silver nanoparticles and its biofilm activity against clinical strains Pseudomonas aeruginosa.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {168}, number = {}, pages = {107-116}, doi = {10.1016/j.jphotobiol.2017.02.004}, pmid = {28212517}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/isolation & purification/pharmacology ; *Biodegradation, Environmental ; Biofilms/*drug effects ; Coloring Agents/*metabolism ; Lagerstroemia ; Metal Nanoparticles/*chemistry ; Plant Extracts/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Silver ; }, abstract = {The aim of this study was to prepare silver nanoparticles by a green method using the aqueous leaves extract of Lagerstroemia speciosa. The prepared silver nanoparticles were characterized, studied for its photocatalytic and biofilm inhibition studies. The maximum absorbance peak was found at 427nm and thus confirming the formation of silver nanoparticles. The average size of silver nanoparticles synthesized was found to be 12nm using XRD and it was spherical in shape. The nanoparticles synthesized was investigated for photocatalytic activity for to two different dye molecules, methyl orange and methylene blue showing 310 and 290min degradation time respectively. The silver nanoparticles biofilm inhibition assay against clinical strains of Pseudomonas aeruginosa showed lowest accumulation at a lower concentration. The biofilm inhibition was also studied by visual interpretation through Scanning Electron Microscopy states that 50μgmL[-1] exerts the highest inhibition compared against the control. This evident helps to analysis the silver nanoparticles for various applications in future.}, } @article {pmid28212280, year = {2017}, author = {Fusco, A and Coretti, L and Savio, V and Buommino, E and Lembo, F and Donnarumma, G}, title = {Biofilm Formation and Immunomodulatory Activity of Proteus mirabilis Clinically Isolated Strains.}, journal = {International journal of molecular sciences}, volume = {18}, number = {2}, pages = {}, pmid = {28212280}, issn = {1422-0067}, mesh = {Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Host-Pathogen Interactions/immunology ; Humans ; *Immunomodulation ; Phenotype ; Proteus Infections/*immunology/*microbiology ; Proteus mirabilis/classification/isolation & purification/*physiology ; Urinary Tract Infections/immunology/microbiology ; Virulence Factors ; }, abstract = {Urinary tract infections (UTIs) and catheter-associated UTIs (CAUTIs) are the principal hospital-acquired infections. Proteus mirabilis is characterized by several virulence factors able to promote adhesion and biofilm formation and ameliorate the colonization of urinary tract and the formation of crystalline biofilms on the abiotic surface of the urinary catheters. Since, to date, the role of P. mirabilis in the etiopathogenesis of different types of urinary tract infections is not well established, in this study we sought to characterize two different clinically isolated strains of P. mirabilis (PM1 and PM2) with distinctive phenotypes and analyzed various virulence factors possibly implicated in the ability to induce UTIs and CAUTIs. In particular, we analyzed motility, biofilm formation both on abiotic and biotic surfaces of PM1 and PM2 and paralleled these parameters with the ability to induce an inflammatory response in an epithelial cell model. Results showed that PM1 displayed major motility and a capacity to form biofilm and was associated with an anti-inflammatory response of host cells. Conversely, PM2 exhibited lack motility and a had slower organization in biofilm but promoted an increase of proinflammatory cytokine expression in infected epithelial cells. Our study provides data useful to start uncovering the pathologic basis of P. mirabilis-associated urinary infections. The evidence of different virulence factors expressed by PM1 and PM2 highlights the possibility to use precise and personalized therapies targeting specific virulence pathways.}, } @article {pmid28211475, year = {2017}, author = {Kirchhoff, L and Olsowski, M and Zilmans, K and Dittmer, S and Haase, G and Sedlacek, L and Steinmann, E and Buer, J and Rath, PM and Steinmann, J}, title = {Biofilm formation of the black yeast-like fungus Exophiala dermatitidis and its susceptibility to antiinfective agents.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {42886}, pmid = {28211475}, issn = {2045-2322}, mesh = {Antifungal Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Catechin/analogs & derivatives/pharmacology ; Colistin/pharmacology ; Cystic Fibrosis/*complications/microbiology ; Echinocandins/pharmacology ; Exophiala/drug effects/isolation & purification/*physiology ; Farnesol/pharmacology ; Humans ; Lipopeptides/pharmacology ; Micafungin ; Microbial Sensitivity Tests ; Mycoses/*microbiology ; Voriconazole/pharmacology ; beta-Glucans/pharmacology ; }, abstract = {Various fungi have the ability to colonize surfaces and to form biofilms. Fungal biofilm-associated infections are frequently refractory to targeted treatment because of resistance to antifungal drugs. One fungus that frequently colonises the respiratory tract of cystic fibrosis (CF) patients is the opportunistic black yeast-like fungus Exophiala dermatitidis. We investigated the biofilm-forming ability of E. dermatitidis and its susceptibility to various antiinfective agents and natural compounds. We tested 58 E. dermatitidis isolates with a biofilm assay based on crystal violet staining. In addition, we used three isolates to examine the antibiofilm activity of voriconazole, micafungin, colistin, farnesol, and the plant derivatives 1,2,3,4,6-penta-O-galloyl-b-D-glucopyranose (PGG) and epigallocatechin-3-gallate (EGCG) with an XTT reduction assay. We analysed the effect of the agents on cell to surface adhesion, biofilm formation, and the mature biofilm. The biofilms were also investigated by confocal laser scan microscopy. We found that E. dermatitidis builds biofilm in a strain-specific manner. Invasive E. dermatitidis isolates form most biomass in biofilm. The antiinfective agents and the natural compounds exhibited poor antibiofilm activity. The greatest impact of the compounds was detected when they were added prior cell adhesion. These findings suggest that prevention may be more effective than treatment of biofilm-associated E. dermatitidis infections.}, } @article {pmid28210465, year = {2016}, author = {Taheran, L and Zarrini, G and Khorram, S and Zakerhamidi, MS}, title = {Plasma surface modification as a new approach to protect urinary catheter against Escherichia coli biofilm formation.}, journal = {Iranian journal of microbiology}, volume = {8}, number = {4}, pages = {257-262}, pmid = {28210465}, issn = {2008-3289}, abstract = {BACKGROUND AND OBJECTIVES: Biomaterials are widely used in medical devices such as urinary catheters. One of the main problems associated with long term using of the urinary catheters is biofilm formation on their surfaces. Many techniques have been presented to reduce the biofilm formation. One of the most revolutionary techniques allowing such surface fictionalization is plasma surface modification.

MATERIALS AND METHODS: In this study, a glow discharge plasma (GDP) effect on Escherichia coli biofilm formation on the surface of urinary catheter in the pressure of 1.6 × 10[-1] Torr of nitrogen, discharge voltage about 1.2 kV and current of 150 mA for 20 minutes has been investigated. Crystal violet binding assay and sonication method were performed in order to evaluate the amount of biofilm formation on tested biomaterials.

RESULTS: Characterization of modified surfaces by Attenuated Total Reflectance Fourier Transform Infrared Spectrometry (ATR-FTIR) and atomic force microscopy (AFM) revealed a noticeable change in hydrophobicity and roughness of catheter surfaces achieved by nitrogen plasma. The results of crystal violet binding assay and sonication method showed that the amount of biofilm formation on modified surface was about 86% less than the pristine sample.

CONCLUSION: Plasma surface modification can reduce the risk of infections in patients with long-term use of urinary catheters.}, } @article {pmid28209374, year = {2017}, author = {Suresh, L and Sagar Vijay Kumar, P and Poornachandra, Y and Ganesh Kumar, C and Chandramouli, GVP}, title = {Design, synthesis and evaluation of novel pyrazolo-pyrimido[4,5-d]pyrimidine derivatives as potent antibacterial and biofilm inhibitors.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {27}, number = {6}, pages = {1451-1457}, doi = {10.1016/j.bmcl.2017.01.087}, pmid = {28209374}, issn = {1464-3405}, mesh = {Anti-Bacterial Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Microbial Sensitivity Tests ; Pyrazoles/*chemistry ; Pyrimidines/chemical synthesis/*chemistry/*pharmacology ; Reactive Oxygen Species/metabolism ; }, abstract = {An efficient four-component reaction of 6-amino-1,3-dimethyluracil, N,N-dimethylformamide dimethylacetal, 1-phenyl-3-(4-substituted-phenyl)-4-formyl-1H-pyrazoles and aromatic amines was conducted in the presence of [Bmim]FeCl4 ionic liquid as a promoting medium. This strategy provided a convenient route without any additional catalyst or metal salt under mild conditions. All the synthesized pyrazolo-pyrimido[4,5-d]pyrimidines derivatives were evaluated for their antibacterial, minimum bactericidal concentration (MBC), biofilm inhibition, intracellular ROS accumulation and protein leakage activities. The results revealed that among all the screened derivatives, the compounds 5c, 5i, 5l and 5m were quite promising with MIC values ranging between 3.9 and 15.6μg/mL, while the MBC values were 2-fold the antibacterial activity values. The biofilm inhibition activity revealed that the compounds 5l and 5m exhibited promising activity with IC50 values ranging between 1.8 and 8.2μg/mL. It was observed that at a concentration of 0.5μg/mL, the compound 5l treated biofilms of Micrococcus luteus showed increased levels of intracellular ROS accumulation. Further, the protein leakage study revealed that the Micrococcus luteus cells treated with compound 5l caused membrane permeability which resulted in protein leakage and subsequent bacterial cell death.}, } @article {pmid28208623, year = {2017}, author = {Neu, TR and Kuhlicke, U}, title = {Fluorescence Lectin Bar-Coding of Glycoconjugates in the Extracellular Matrix of Biofilm and Bioaggregate Forming Microorganisms.}, journal = {Microorganisms}, volume = {5}, number = {1}, pages = {}, pmid = {28208623}, issn = {2076-2607}, abstract = {Microbial biofilm systems are defined as interface-associated microorganisms embedded into a self-produced matrix. The extracellular matrix represents a continuous challenge in terms of characterization and analysis. The tools applied in more detailed studies comprise extraction/chemical analysis, molecular characterization, and visualisation using various techniques. Imaging by laser microscopy became a standard tool for biofilm analysis, and, in combination with fluorescently labelled lectins, the glycoconjugates of the matrix can be assessed. By employing this approach a wide range of pure culture biofilms from different habitats were examined using the commercially available lectins. From the results, a binary barcode pattern of lectin binding can be generated. Furthermore, the results can be fine-tuned and transferred into a heat map according to signal intensity. The lectin barcode approach is suggested as a useful tool for investigating the biofilm matrix characteristics and dynamics at various levels, e.g. bacterial cell surfaces, adhesive footprints, individual microcolonies, and the gross biofilm or bio-aggregate. Hence fluorescence lectin bar-coding (FLBC) serves as a basis for a subsequent tailor-made fluorescence lectin-binding analysis (FLBA) of a particular biofilm. So far, the lectin approach represents the only tool for in situ characterization of the glycoconjugate makeup in biofilm systems. Furthermore, lectin staining lends itself to other fluorescence techniques in order to correlate it with cellular biofilm constituents in general and glycoconjugate producers in particular.}, } @article {pmid28208370, year = {2017}, author = {Zachreson, C and Wolff, C and Whitchurch, CB and Toth, M}, title = {Emergent pattern formation in an interstitial biofilm.}, journal = {Physical review. E}, volume = {95}, number = {1-1}, pages = {012408}, doi = {10.1103/PhysRevE.95.012408}, pmid = {28208370}, issn = {2470-0053}, mesh = {Animals ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Computer Simulation ; Elasticity ; Extracellular Fluid/*microbiology ; Fimbriae, Bacterial/physiology ; *Models, Biological ; Movement/physiology ; Viscosity ; }, abstract = {Collective behavior of bacterial colonies plays critical roles in adaptability, survivability, biofilm expansion and infection. We employ an individual-based model of an interstitial biofilm to study emergent pattern formation based on the assumptions that rod-shaped bacteria furrow through a viscous environment and excrete extracellular polymeric substances which bias their rate of motion. Because the bacteria furrow through their environment, the substratum stiffness is a key control parameter behind the formation of distinct morphological patterns. By systematically varying this property (which we quantify with a stiffness coefficient γ), we show that subtle changes in the substratum stiffness can give rise to a stable state characterized by a high degree of local order and long-range pattern formation. The ordered state exhibits characteristics typically associated with bacterial fitness advantages, even though it is induced by changes in environmental conditions rather than changes in biological parameters. Our findings are applicable to a broad range of biofilms and provide insights into the relationship between bacterial movement and their environment, and basic mechanisms behind self-organization of biophysical systems.}, } @article {pmid28205337, year = {2017}, author = {Pandin, C and Le Coq, D and Canette, A and Aymerich, S and Briandet, R}, title = {Should the biofilm mode of life be taken into consideration for microbial biocontrol agents?.}, journal = {Microbial biotechnology}, volume = {10}, number = {4}, pages = {719-734}, pmid = {28205337}, issn = {1751-7915}, mesh = {Biofilms/*drug effects/*growth & development ; Biological Control Agents/*metabolism ; Pest Control, Biological/*methods ; Plant Diseases/*prevention & control ; }, abstract = {Almost one-third of crop yields are lost every year due to microbial alterations and diseases. The main control strategy to limit these losses is the use of an array of chemicals active against spoilage and unwanted pathogenic microorganisms. Their massive use has led to extensive environmental pollution, human poisoning and a variety of diseases. An emerging alternative to this chemical approach is the use of microbial biocontrol agents. Biopesticides have been used with success in several fields, but a better understanding of their mode of action is necessary to better control their activity and increase their use. Very few studies have considered that biofilms are the preferred mode of life of microorganisms in the target agricultural biotopes. Increasing evidence shows that the spatial organization of microbial communities on crop surfaces may drive important bioprotection mechanisms. The aim of this review is to summarize the evidence of biofilm formation by biocontrol agents on crops and discuss how this surface-associated mode of life may influence their biology and interactions with other microorganisms and the host and, finally, their overall beneficial activity.}, } @article {pmid28204863, year = {2017}, author = {Otton, LM and da Silva Campos, M and Meneghetti, KL and Corção, G}, title = {Influence of twitching and swarming motilities on biofilm formation in Pseudomonas strains.}, journal = {Archives of microbiology}, volume = {199}, number = {5}, pages = {677-682}, doi = {10.1007/s00203-017-1344-7}, pmid = {28204863}, issn = {1432-072X}, mesh = {4-Butyrolactone/*analogs & derivatives/pharmacology ; Bacterial Adhesion/genetics ; Biofilms/*growth & development ; Fimbriae, Bacterial/*drug effects ; Pseudomonas Infections ; Pseudomonas aeruginosa/growth & development/*metabolism/*pathogenicity ; Virulence Factors/genetics ; }, abstract = {The genus Pseudomonas mainly includes opportunistic pathogens that rely on type IV pili as an important virulence factor, which is associated with adherence and biofilm formation. Pseudomonas infections are well known to be persistent and resilient in nature largely because of the tendency of the species to form biofilms. This study aimed at analyzing environmental strains of Pseudomonas genus with respect to their ability to execute twitching and swarming motilities as well as with respect to their ability to form biofilms both in the presence as well as in the absence of furanone, a substance that has the potential to prevent the formation of biofilms. Strains of Pseudomonas aeruginosa and strains belonging to other species of the genus were analyzed. Twitching and swarming motility assays and biofilm-formation assays, both in the presence as well as in the absence of furanone, were performed. In twitching assay strains belonging to P. aeruginosa outperformed those belonging to other species. Interestingly, it was seen that the presence of furanone had a negative impact on formation of twitching and swarming motility zones. In the case of biofilm assays, it was observed that the presence of furanone resulted in an observable decrease in the degree of adhesion in 30% of the analyzed strains. Thus, from our results, it can be concluded that, as compared to other species, the strains belonging to P. aeruginosa exhibit a higher potential for twitching motility and similar performance in swarming motility and biofilm formation. It can also be concluded that furanone has the potential to interfere with both motilities as well as with biofilm formation.}, } @article {pmid28204565, year = {2017}, author = {Tobudic, S and Harrison, N and Forstner, C and Kussman, M and Burgmann, H}, title = {Effect of peritoneal dialysis fluids on activity of echinocandins against Candida spp. biofilm.}, journal = {Medical mycology}, volume = {55}, number = {7}, pages = {790-793}, doi = {10.1093/mmy/myw145}, pmid = {28204565}, issn = {1460-2709}, mesh = {Antifungal Agents/*metabolism ; Biofilms/*drug effects ; Candida/*drug effects/*physiology ; Dialysis Solutions/chemistry/*metabolism ; *Drug Interactions ; Echinocandins/*metabolism ; Humans ; Peritoneal Dialysis ; }, abstract = {Peritoneal dialysis fluids (PDFs) impair microorganisms' growth, which may compromise effectivity of some antimicrobials. The purpose of this study was to investigate the effect of three different PDFs (lactate/bicarbonate-buffered Physioneal 40® with 2.2% glucose, lactate-buffered Nutrineal PD4® with 1.1% amino acid, and lactate-buffered Extraneal® with 7.5% icodextrin) on biofilm formation of four different Candida spp and antibiofilm effectiveness of anidulafungin, caspofungin and micafungin against Candida spp. biofilm in PDFs. All tested PDFs attained inhibitory effect on the biofilm formation but also reduced biofilm effectiveness of echinocandins against biofilm in PDFs was detected.}, } @article {pmid28203673, year = {2017}, author = {Nizalapur, S and Kimyon, O and Yee, E and Ho, K and Berry, T and Manefield, M and Cranfield, CG and Willcox, M and Black, DS and Kumar, N}, title = {Amphipathic guanidine-embedded glyoxamide-based peptidomimetics as novel antibacterial agents and biofilm disruptors.}, journal = {Organic & biomolecular chemistry}, volume = {15}, number = {9}, pages = {2033-2051}, doi = {10.1039/c7ob00053g}, pmid = {28203673}, issn = {1477-0539}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Cell Line ; Dose-Response Relationship, Drug ; Escherichia coli/*drug effects ; Fibroblasts/drug effects ; Guanidine/*chemistry/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Peptidomimetics/chemical synthesis/chemistry/*pharmacology ; Staphylococcus aureus/*drug effects ; Structure-Activity Relationship ; Sulfonylurea Compounds/chemistry/*pharmacology ; }, abstract = {Antimicrobial resistance in bacteria is becoming increasingly prevalent, posing a critical challenge to global health. Bacterial biofilm formation is a common resistance mechanism that reduces the effectiveness of antibiotics. Thus, the development of compounds that can disrupt bacterial biofilms is a potential strategy to combat antimicrobial resistance. We report herein the synthesis of amphipathic guanidine-embedded glyoxamide-based peptidomimetics via ring-opening reactions of N-naphthoylisatins with amines and amino acids. These compounds were investigated for their antibacterial activity by the determination of minimum inhibitory concentration (MIC) against S. aureus and E. coli. Compounds 35, 36, and 66 exhibited MIC values of 6, 8 and 10 μg mL[-1] against S. aureus, respectively, while compounds 55 and 56 showed MIC values of 17 and 19 μg mL[-1] against E. coli, respectively. Biofilm disruption and inhibition activities were also evaluated against various Gram-positive and Gram-negative bacteria. The most active compound 65 exhibited the greatest disruption of established biofilms by 65% in S. aureus, 61% in P. aeruginosa, and 60% in S. marcescens respectively, at 250 μM concentration, while compound 52 inhibited the formation of biofilms by 72% in S. marcescens at 250 μM. We also report here the in vitro toxicity against MRC-5 human lung fibroblast cells. Finally, the pore forming capability of the three most potent compounds were tested using tethered bilayer lipid membrane (tBLM) technology.}, } @article {pmid28201751, year = {2016}, author = {P Steenackers, H and Parijs, I and Dubey, A and Foster, KR and Vanderleyden, J}, title = {Experimental evolution in biofilm populations.}, journal = {FEMS microbiology reviews}, volume = {40}, number = {6}, pages = {980}, doi = {10.1093/femsre/fuw030}, pmid = {28201751}, issn = {1574-6976}, support = {242670/ERC_/European Research Council/International ; }, } @article {pmid28199190, year = {2017}, author = {Darwish Alipour Astaneh, S and Rasooli, I and Mousavi Gargari, SL}, title = {Filamentous hemagglutinin adhesin FhaB limits A.baumannii biofilm formation.}, journal = {Frontiers in bioscience (Elite edition)}, volume = {9}, number = {2}, pages = {266-275}, doi = {10.2741/e801}, pmid = {28199190}, issn = {1945-0508}, mesh = {Acinetobacter baumannii/genetics/*pathogenicity/physiology ; Adhesins, Bacterial/chemistry/genetics/*physiology ; Amino Acid Sequence ; Bacterial Adhesion/genetics ; Biofilms ; Cloning, Molecular ; Computational Biology ; Conserved Sequence ; Escherichia coli/genetics ; Gene Expression Regulation, Bacterial ; Hydrophobic and Hydrophilic Interactions ; Recombinant Fusion Proteins ; Sequence Alignment ; }, abstract = {Increased resistance and survival, as well as immune evasion, play a significant role in the pathogenicity of Acinetobacter baumannii. Here, we report on the adhesion of the bacterium to epithelial cells and formation of biofilm on abiotic surfaces. We identificed autotransporter (AT) genes that encode homologues (Fha-like) of the two-partner secretion system (TPS) in A.baumannii (ATCC19606) which we designate as FhaB (exoprotein) and FhaC (transporter) and demonstrate that these novel genes, are under the control of distinct regulatable promoters within either the same (FhaBC) or two distinct (FhaB and FhaC) cells. The expression of this gene in outer membrane protein (OM) showed them to be deficient in the adherence to A546 cells. FhaB is involved in hydrophobicity of A. baumannii ATCC19606 while FhaBC is associated with biofilm formation. The vaccinogenic potential of FHA-like proteins offers use of these targets as novel therapeutic strategies to limit A.baumannii associated morbidity and mortality.}, } @article {pmid28199146, year = {2017}, author = {Lee, Y and Wang, C}, title = {Morphological Change and Decreasing Transfer Rate of Biofilm-Featured Listeria monocytogenes EGDe.}, journal = {Journal of food protection}, volume = {80}, number = {3}, pages = {368-375}, doi = {10.4315/0362-028X.JFP-16-226}, pmid = {28199146}, issn = {1944-9097}, mesh = {Bacterial Adhesion ; *Biofilms ; Colony Count, Microbial ; Equipment Contamination ; Food Contamination ; Food Microbiology ; *Listeria monocytogenes ; Stainless Steel ; }, abstract = {Listeria monocytogenes , a lethal foodborne pathogen, has the ability to resist the hostile food processing environment and thus frequently contaminates ready-to-eat foods during processing. It is commonly accepted that the tendency of L. monocytogenes ' to generate biofilms on various surfaces enhances its resistance to the harshness of the food processing environment. However, the role of biofilm formation in the transferability of L. monocytogenes EGDe remains controversial. We examined the growth of Listeria biofilms on stainless steel surfaces and their effect on the transferability of L. monocytogenes EGDe. The experiments were a factorial 2 × 2 design with at least three biological replicates. Through scanning electron microscopy, a mature biofilm with intensive aggregates of cells was observed on the surface of stainless steel after 3 or 5 days of incubation, depending on the initial level of inoculation. During biofilm development, L. monocytogenes EGDe carried out binary fission vigorously before a mature biofilm was formed and subsequently changed its cellular morphology from rod shaped to sphere shaped. Furthermore, static biofilm, which was formed after 3 days of incubation at 25°C, significantly inhibited the transfer rate of L. monocytogenes EGDe from stainless steel blades to 15 bologna slices. During 7 days of storage at 4°C, however, bacterial growth rate was not significantly impacted by whether bacteria were transferred from biofilm and the initial concentrations of transferred bacteria on the slice. In conclusion, this study is the first to report a distinct change in morphology of L. monocytogenes EGDe at the late stage of biofilm formation. More importantly, once food is contaminated by L. monocytogenes EGDe, contamination proceeds independently of biofilm development and the initial level of contamination when food is stored at 4°C, even if contamination with L. monocytogenes EGDe was initially undetectable before storage.}, } @article {pmid28198348, year = {2017}, author = {Rastogi, S and Singh, AK and Pant, G and Mitra, K and Sashidhara, KV and Krishnan, MY}, title = {Down-regulation of PE11, a cell wall associated esterase, enhances the biofilm growth of Mycobacterium tuberculosis and reduces cell wall virulence lipid levels.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {1}, pages = {52-61}, doi = {10.1099/mic.0.000417}, pmid = {28198348}, issn = {1465-2080}, mesh = {Bacterial Proteins/*biosynthesis/genetics ; Biofilms/*growth & development ; Cell Line ; Cell Wall/*metabolism ; Esterases/*biosynthesis/genetics ; Fibronectins/metabolism ; Gene Knockout Techniques ; Humans ; Lipids/biosynthesis ; Macrophages/microbiology ; Membrane Lipids/*metabolism ; Mycobacterium smegmatis/genetics/pathogenicity ; Mycobacterium tuberculosis/genetics/*growth & development/*pathogenicity ; Mycolic Acids/metabolism ; Tetradecanoylphorbol Acetate/pharmacology ; Trehalose/metabolism ; Virulence Factors/metabolism ; }, abstract = {PE11 (Rv1169c or LipX) is a cell wall associated esterase/lipase of Mycobacterium tuberculosis (Mtb). Evidences suggest that PE11 is expressed by Mtb both in vitro and in vivo. Previous studies have shown that PE11 leads to modification in cell wall lipid content and enhanced virulence when expressed in the non-pathogenic surrogate Mycobacterium smegmatis. Since cell wall lipids often play different roles in pathogenic and non-pathogenic mycobacteria, we investigated the role of PE11 in its host, Mtb. Mtb with lowered expression of PE11 (PE11 knock-down) displayed significant changes in colony morphology and cell wall lipid profile, confirming the role of PE11 in cell wall architecture. In addition, the levels of phthiocerol dimycocerosates, a cell wall virulence factor, were decreased. Levels of trehalose esters and free mycolic acids were increased. In contrast to M. smegmatis expressing Mtb PE11, a role reversal was observed in Mtb with respect to pellicle/biofilm formation. The PE11 knock-down Mtb strain showed significantly enhanced aggregation and early biofilm growth in detergent-free medium, compared to the wild-type. Knock-down strain also showed nearly 27-fold up-regulation of a fibronectin attachment protein (Rv1759c), linking biofilm growth with over-expression of bacterial proteins that help in aggregation and/or binding to host extracellular matrix. The knock-down also resulted in poor virulence of Mtb in PMA (phorbol 12-myristate 13-acetate) treated and PMA+IFN-γ treated THP-1 macrophages. Therefore, the study not only links PE11 to cell wall virulence lipids but also reveals the involvement of this cell wall associated esterase in down-regulation of biofilm in Mtb.}, } @article {pmid28194111, year = {2017}, author = {Bai, J and Yang, Y and Wang, S and Gao, L and Chen, J and Ren, Y and Ding, W and Muhammad, I and Li, Y}, title = {Syringa oblata Lindl. Aqueous Extract Is a Potential Biofilm Inhibitor in S. suis.}, journal = {Frontiers in pharmacology}, volume = {8}, number = {}, pages = {26}, pmid = {28194111}, issn = {1663-9812}, abstract = {Streptococcus suis (S. suis) is a zoonotic pathogen that causes severe disease symptoms in pigs and humans. Syringa oblata Lindl. distributed in the middle latitudes of Eurasia and North America were proved as the most development potential of Chinese Medicine. In this study, biofilm formation by S. suis decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of Syringa oblata Lindl. aqueous extract and rutin. Scanning electron microscopy analysis revealed the potential effect of Syringa oblata Lindl. aqueous extract and rutin against biofilm formation by S. suis. Using iTRAQ technology, comparative proteomic analyses was performed at two conditions: 1/2 MIC of Syringa oblata Lindl. aqueous extract treated and non-treated cells. The results revealed the existence of 28 proteins of varying amounts. We found that the majority of the proteins were related to cell growth and metabolism. We also found that Syringa oblata Lindl. Aqueous extract affected the synthesis enzymes. In summary, Syringa oblata Lindl. aqueous extract might be used to inhibit the biofilm formation effectively by S. suis, and the active ingredients of the Syringa oblate Lindl. aqueous extract is rutin. The content of rutin is 9.9 ± 0.089 mg/g dry weight.}, } @article {pmid28193570, year = {2017}, author = {Ciandrini, E and Campana, R and Baffone, W}, title = {Live and heat-killed Lactobacillus spp. interfere with Streptococcus mutans and Streptococcus oralis during biofilm development on titanium surface.}, journal = {Archives of oral biology}, volume = {78}, number = {}, pages = {48-57}, doi = {10.1016/j.archoralbio.2017.02.004}, pmid = {28193570}, issn = {1879-1506}, mesh = {*Antibiosis ; Bacterial Adhesion ; Biofilms/*growth & development ; Hot Temperature ; Lactobacillus/*physiology ; Streptococcus mutans/*growth & development ; Streptococcus oralis/*growth & development ; Surface Properties ; Titanium/*chemistry ; }, abstract = {OBJECTIVES: This research investigates the ability of live and heat-killed (HK) Lactic Acid Bacteria (LAB) to interfere with Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 during biofilm formation.

DESIGN: Eight Lactobacillus spp. and two oral colonizers, pathogenic Streptococcus mutans and resident Streptococcus oralis, were characterized for their aggregation abilities, cell surface properties and biofilm formation ability on titanium surface. Then, the interference activity of selected live and HK Lactobacillus spp. during S. mutans and S. oralis biofilm development were performed. The cell-free culture supernatants (CFCS) anti-biofilm activity was also determined.

RESULTS: LAB possess good abilities of auto-aggregation (from 14.19 to 28.97%) and of co-aggregation with S. oralis. The cell-surfaces characteristics were most pronounced in S. mutans and S. oralis, while the highest affinities to xylene and chloroform were observed in Lactobacillus rhamnosus ATCC 53103 (56.37%) and Lactobacillus paracasei B21060 (43.83%). S. mutans and S. oralis developed a biofilm on titanium surface, while LAB showed a limited or no ability to create biofilm. Live and HK L. rhamnosus ATCC 53103 and L. paracasei B21060 inhibited streptococci biofilm formation by competition and displacement mechanisms with no substantial differences. The CFCSs of both LAB strains, particularly the undiluted one of L. paracasei B21060, decreased S. mutans and S. oralis biofilm formation.

CONCLUSIONS: This study evidenced the association of LAB aggregation abilities and cell-surface properties with the LAB-mediated inhibition of S. mutans and S. oralis biofilm formation. Lactobacilli showed different mechanisms of action and peculiar strain-specific characteristics, maintained also in the heat-killed LAB.}, } @article {pmid28192619, year = {2017}, author = {Coi, AL and Bigey, F and Mallet, S and Marsit, S and Zara, G and Gladieux, P and Galeote, V and Budroni, M and Dequin, S and Legras, JL}, title = {Genomic signatures of adaptation to wine biological ageing conditions in biofilm-forming flor yeasts.}, journal = {Molecular ecology}, volume = {26}, number = {7}, pages = {2150-2166}, doi = {10.1111/mec.14053}, pmid = {28192619}, issn = {1365-294X}, mesh = {Adaptation, Physiological/*genetics ; Biofilms ; Fermentation ; *Genetics, Population ; Genome, Fungal ; Phenotype ; Phylogeny ; Polymorphism, Single Nucleotide ; Saccharomyces cerevisiae/*genetics ; Selection, Genetic ; Wine/*microbiology ; }, abstract = {The molecular and evolutionary processes underlying fungal domestication remain largely unknown despite the importance of fungi to bioindustry and for comparative adaptation genomics in eukaryotes. Wine fermentation and biological ageing are performed by strains of S. cerevisiae with, respectively, pelagic fermentative growth on glucose and biofilm aerobic growth utilizing ethanol. Here, we use environmental samples of wine and flor yeasts to investigate the genomic basis of yeast adaptation to contrasted anthropogenic environments. Phylogenetic inference and population structure analysis based on single nucleotide polymorphisms revealed a group of flor yeasts separated from wine yeasts. A combination of methods revealed several highly differentiated regions between wine and flor yeasts, and analyses using codon-substitution models for detecting molecular adaptation identified sites under positive selection in the high-affinity transporter gene ZRT1. The cross-population composite likelihood ratio revealed selective sweeps at three regions, including in the hexose transporter gene HXT7, the yapsin gene YPS6 and the membrane protein coding gene MTS27. Our analyses also revealed that the biological ageing environment has led to the accumulation of numerous mutations in proteins from several networks, including Flo11 regulation and divalent metal transport. Together, our findings suggest that the tuning of FLO11 expression and zinc transport networks are a distinctive feature of the genetic changes underlying the domestication of flor yeasts. Our study highlights the multiplicity of genomic changes underlying yeast adaptation to man-made habitats and reveals that flor/wine yeast lineage can serve as a useful model for studying the genomics of adaptive divergence.}, } @article {pmid28187188, year = {2017}, author = {Rath, H and Stumpp, SN and Stiesch, M}, title = {Development of a flow chamber system for the reproducible in vitro analysis of biofilm formation on implant materials.}, journal = {PloS one}, volume = {12}, number = {2}, pages = {e0172095}, pmid = {28187188}, issn = {1932-6203}, mesh = {Aggregatibacter/physiology ; *Biofilms ; Dental Implants/*microbiology ; Microfluidics/*instrumentation/methods ; Porphyromonas/physiology ; Streptococcus/physiology ; }, abstract = {Since the introduction of modern dental implants in the 1980s, the number of inserted implants has steadily increased. Implant systems have become more sophisticated and have enormously enhanced patients' quality of life. Although there has been tremendous development in implant materials and clinical methods, bacterial infections are still one of the major causes of implant failure. These infections involve the formation of sessile microbial communities, called biofilms. Biofilms possess unique physical and biochemical properties and are hard to treat conventionally. There is a great demand for innovative methods to functionalize surfaces antibacterially, which could be used as the basis of new implant technologies. Present, there are few test systems to evaluate bacterial growth on these surfaces under physiological flow conditions. We developed a flow chamber model optimized for the assessment of dental implant materials. As a result it could be shown that biofilms of the five important oral bacteria Streptococcus gordonii, Streptococcus oralis, Streptococcus salivarius, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans, can be reproducibly formed on the surface of titanium, a frequent implant material. This system can be run automatically in combination with an appropriate microscopic device and is a promising approach for testing the antibacterial effect of innovative dental materials.}, } @article {pmid28185089, year = {2017}, author = {Prażmo, EJ and Godlewska, RA and Mielczarek, AB}, title = {Effectiveness of repeated photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm: an in vitro study.}, journal = {Lasers in medical science}, volume = {32}, number = {3}, pages = {655-661}, pmid = {28185089}, issn = {1435-604X}, mesh = {Adult ; Biofilms/drug effects/*radiation effects ; Colony Count, Microbial ; Dental Pulp Cavity/drug effects/*microbiology/radiation effects ; Disinfection ; Enterococcus faecalis/growth & development/isolation & purification/*radiation effects ; Humans ; Male ; Photochemotherapy/*methods ; Photosensitizing Agents/pharmacology ; Root Canal Preparation/methods ; Treatment Outcome ; }, abstract = {The study aimed to investigate the effectiveness of photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm and to analyse how a repeated light irradiation, replenishment of oxygen and photosensitiser affect the results of the photodynamic disinfecting protocol. After chemomechanical preparation, 46 single-rooted human teeth were infected with a clinical strain of E. faecalis and incubated for a week in microaerobic conditions. The experimental procedures included groups of single application of photodynamic therapy, two cycles of PDT, irrigation with 5.25% NaOCl solution and negative and positive control. The number of residing bacterial colonies in the root canals was determined based on the CFU/ml method. In the group of preparations irrigated with NaOCl, bacterial colonies were not observed. A single PDT eliminated 45% of the initial CFU/ml. Repeated PDT eradicated 95% of the intracanal bacterial biofilm. Photodynamic therapy has a high potential for the elimination of E. faecalis biofilm. There is a safe therapeutic window where photoinduced disinfection can be used as an adjuvant to conventional endodontic treatment, which remains the most effective.}, } @article {pmid28183669, year = {2017}, author = {Krishnan, M and Dahms, HU and Seeni, P and Gopalan, S and Sivanandham, V and Jin-Hyoung, K and James, RA}, title = {Multi metal assessment on biofilm formation in offshore environment.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {73}, number = {}, pages = {743-755}, doi = {10.1016/j.msec.2016.12.062}, pmid = {28183669}, issn = {1873-0191}, mesh = {Analysis of Variance ; Bacteria/drug effects/isolation & purification ; Bacterial Adhesion/drug effects ; Base Sequence ; Biofilms/*drug effects ; DNA, Ribosomal/genetics ; Heterotrophic Processes/drug effects ; Metals/*pharmacology ; Metals, Heavy/analysis ; Microscopy, Fluorescence ; Phylogeny ; Seasons ; Seawater ; Species Specificity ; }, abstract = {Eight metal and non-metal coupons were exposed to seawater in offshore platform laboratory on biofilm formation in seven days of every month interval time for one year period. Among metal coupons, the highest mean heterotrophic biofilm bacteria population (HBBP) ranges were observed in mild steel (MS) coupon (33.03 to 40.00 [×10[4]] CFUscm[-2]) and lowest in copper (Cu) coupon (3.0 to 5.1 [×10[4]] CFUscm[-2]). Non-metal coupons show, highest mean HBBP ranges in glass (GL) coupon (29.6 to 66.0 [×10[4]] CFUscm[-2]) and lowest in polyvinyl chloride (PVC) coupon (34.4 to 52.5 [×10[4]] CFUscm[-2]). Within the studied coupons, high HBBP level was witnessed in GL and simultaneously low in Cu due to its toxic leaching product of Cu2O. Gram-positive bacterial deposit show dominated trend in all coupons with increasing order of Cu>SS>MS>PVC>GL>Cu-Ni 70/30>Cu-Ni 90/10>Br and Gram-negative show different in the order of Br>Cu-Ni 90/10>Cu-Ni 70/30>GL>PVC>MS>SS>Cu, respectively. The 16S rDNA sequence confirmed, heterotrophic biofilm Bacillus sp. (Gram-positive) were dominated in all coupons for all months.}, } @article {pmid28183187, year = {2017}, author = {Dai, Y and Sun, T and Zhang, Z and Zhang, ZJ and Li, JR}, title = {Effect of zinc oxide film morphologies on the formation of Shewanella putrefaciens biofilm.}, journal = {Biointerphases}, volume = {12}, number = {1}, pages = {011002}, doi = {10.1116/1.4976003}, pmid = {28183187}, issn = {1559-4106}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Microscopy ; Nanostructures ; Shewanella putrefaciens/*drug effects/*physiology ; *Surface Properties ; Zinc Oxide/*pharmacology ; }, abstract = {Zinc oxide (ZnO) films were prepared on aluminum substrate by a hydrothermal method to investigate the effect of their surface characteristics, including morphology and hydrophobicity, on the corresponding antibiofilm performance. The surface characteristics of the prepared ZnO films were examined by a comprehensive range of methodologies, suggesting that films of distinctive surface morphologies were successfully formed. Subsequently, their antibiofilm activities, using Shewanella putrefaciens as a model bacterium, were assessed. Surface measurements confirmed that the ZnO films equipped with a nanoscopic needlelike surface feature are more hydrophobic than those possessing densely packed microflakes. The reduced number of live cells and presence of biofilm, confirmed by optical and electron microscopy results, suggest that the former films possess an excellent antibiofilm performance. It is believed that the engineered nanoscopic needle feature might penetrate the cell membrane when they are in contact, allowing the effective substance of ZnO antibacterial ingredients to diffuse into the embedded bacteria. Furthermore, such surface characteristics might perturb the integrity of the cell membrane causing the intracellular substance is leaked from the cells. As such, the combinatorial effects of nanoscopic feature resulted in an inhibited growth of S. putrefaciens biofilm on ZnO film.}, } @article {pmid28181594, year = {2017}, author = {Al-Shabib, NA and Husain, FM and Ahmed, F and Khan, RA and Ahmad, I and Alsharaeh, E and Khan, MS and Hussain, A and Rehman, MT and Yusuf, M and Hassan, I and Khan, JM and Ashraf, GM and Alsalme, A and Al-Ajmi, MF and Tarasov, VV and Aliev, G}, title = {Erratum: Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {42266}, doi = {10.1038/srep42266}, pmid = {28181594}, issn = {2045-2322}, } @article {pmid28181315, year = {2017}, author = {Janeczko, M and Masłyk, M and Kubiński, K and Golczyk, H}, title = {Emodin, a natural inhibitor of protein kinase CK2, suppresses growth, hyphal development, and biofilm formation of Candida albicans.}, journal = {Yeast (Chichester, England)}, volume = {34}, number = {6}, pages = {253-265}, doi = {10.1002/yea.3230}, pmid = {28181315}, issn = {1097-0061}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development ; Casein Kinase II/*antagonists & inhibitors/isolation & purification ; Emodin/*pharmacology ; Hyphae/*drug effects/growth & development ; Microbial Sensitivity Tests ; Microscopy, Fluorescence ; }, abstract = {Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural secondary plant product, originally isolated from the rhizomes of Rheum palmatum. Many reports show its diuretic, vasorelaxant, antibacterial, antiviral, anti-ulcerogenic, immunosuppressive, hepatoprotective, anti-inflammatory and anticancer potential. Emodin is a pleiotropic molecule capable of interacting with several major molecular targets, e.g. NF-κB, AKT/mTOR and STAT3. The compound can also act as an inhibitor of some protein kinases, with special affinity to protein kinase CK2. The aim of the presented report was to evaluate antifungal properties of emodin and its activity towards CK2 isolated from Candida cells. Our studies revealed that the compound suppressed growth of the cells of reference strains as well as clinical Candida strains, with minimal inhibitory concentration and minimal fungicidal concentration values between 12.5 and 200 μg/mL. Moreover, at a low concentration, the compound was able to effectively stop hyphal formation, thus showing a distinct antivirulent potential. Interestingly, we showed that emodin added to Candida culture inhibited the phosphorylation of many cellular proteins, presumably owing to the inhibition of protein kinase CK2. Notably, the enzyme isolated from the Candida cells was susceptible to emodin with IC50 of 2.8 μg/mL. Indeed, our computational modelling revealed that emodin was able to occupy the ATP-binding pocket of CK2. Copyright © 2017 John Wiley & Sons, Ltd.}, } @article {pmid28173636, year = {2017}, author = {Lima, BP and Shi, W and Lux, R}, title = {Identification and characterization of a novel Fusobacterium nucleatum adhesin involved in physical interaction and biofilm formation with Streptococcus gordonii.}, journal = {MicrobiologyOpen}, volume = {6}, number = {3}, pages = {}, pmid = {28173636}, issn = {2045-8827}, support = {R01 DE021108/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/genetics/*metabolism ; *Bacterial Adhesion ; Biofilms/*growth & development ; Fusobacterium nucleatum/metabolism/*physiology ; *Microbial Interactions ; Streptococcus gordonii/*physiology ; }, abstract = {To successfully colonize the oral cavity, bacteria must directly or indirectly adhere to available oral surfaces. Fusobacterium nucleatum plays an important role in oral biofilm community development due to its broad adherence abilities, serving as a bridge between members of the oral biofilm that cannot directly bind to each other. In our efforts to characterize the molecular mechanisms utilized by F. nucleatum to physically bind to key members of the oral community, we investigated the involvement of F. nucleatum outer membrane proteins in its ability to bind to the pioneer biofilm colonizer, Streptococcus gordonii. Here, we present evidence that in addition to the previously characterized fusobacterial adhesin RadD, the interaction between F. nucleatum ATCC 23726 and S. gordonii V288 involves a second outer membrane protein, which we named coaggregation mediating protein A (CmpA). We also characterized the role of CmpA in dual-species biofilm formation with S. gordonii V288, evaluated growth-phase-dependent as well as biofilm expression profiles of radD and cmpA, and confirmed an important role for CmpA, especially under biofilm growth conditions. Our findings underscore the complex set of specific interactions involved in physical binding and thus community integration of interacting bacterial species. This complex set of interactions could have critical implications for the formation and maturation of the oral biofilms in vivo, and could provide clues to the mechanism behind the distribution of organisms inside the human oral cavity.}, } @article {pmid28169492, year = {2017}, author = {Farasin, J and Koechler, S and Varet, H and Deschamps, J and Dillies, MA and Proux, C and Erhardt, M and Huber, A and Jagla, B and Briandet, R and Coppée, JY and Arsène-Ploetze, F}, title = {Comparison of biofilm formation and motility processes in arsenic-resistant Thiomonas spp. strains revealed divergent response to arsenite.}, journal = {Microbial biotechnology}, volume = {10}, number = {4}, pages = {789-803}, pmid = {28169492}, issn = {1751-7915}, mesh = {Arsenites/*metabolism ; Biofilms/*drug effects/*growth & development ; Burkholderiales/*drug effects/genetics/*physiology ; Drug Resistance, Bacterial ; Environmental Pollutants/*metabolism ; Gene Expression Profiling ; Locomotion/*drug effects ; }, abstract = {Bacteria of the genus Thiomonas are found ubiquitously in arsenic contaminated waters such as acid mine drainage (AMD), where they contribute to the precipitation and the natural bioremediation of arsenic. In these environments, these bacteria have developed a large range of resistance strategies among which the capacity to form particular biofilm structures. The biofilm formation is one of the most ubiquitous adaptive response observed in prokaryotes to various stresses, such as those induced in the presence of toxic compounds. This study focused on the process of biofilm formation in three Thiomonas strains (CB1, CB2 and CB3) isolated from the same AMD. The results obtained here show that these bacteria are all capable of forming biofilms, but the architecture and the kinetics of formation of these biofilms differ depending on whether arsenite is present in the environment and from one strain to another. Indeed, two strains favoured biofilm formation, whereas one favoured motility in the presence of arsenite. To identify the underlying mechanisms, the patterns of expression of some genes possibly involved in the process of biofilm formation were investigated in Thiomonas sp. CB2 in the presence and absence of arsenite, using a transcriptomic approach (RNA-seq). The findings obtained here shed interesting light on how the formation of biofilms, and the motility processes contribute to the adaptation of Thiomonas strains to extreme environments.}, } @article {pmid28168528, year = {2017}, author = {Young, B and Delatolla, R and Abujamel, T and Kennedy, K and Laflamme, E and Stintzi, A}, title = {Rapid start-up of nitrifying MBBRs at low temperatures: nitrification, biofilm response and microbiome analysis.}, journal = {Bioprocess and biosystems engineering}, volume = {40}, number = {5}, pages = {731-739}, doi = {10.1007/s00449-017-1739-5}, pmid = {28168528}, issn = {1615-7605}, mesh = {Biofilms/*growth & development ; Bioreactors/*microbiology ; Microbiota/*physiology ; Myxococcales/*physiology ; }, abstract = {The moving bed biofilm reactor (MBBR), operated as a post carbon removal system, requires long start-up times in comparison to carbon removal systems due to slow growing autotrophic organisms. This study investigates the use of carriers seeded in a carbon rich treatment system prior to inoculation in a nitrifying MBBR system to promote the rapid development of nitrifying biofilm in an MBBR system at temperatures between 6 and 8 °C. Results show that nitrification was initiated by the carbon removal carriers after 22 h of operation. High throughput 16S-rDNA sequencing indicates that the sloughing period was a result of heterotrophic organism detachment and the recovery and stabilization period included a growth of Nitrosomonas and Nitrospira as the dominant ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in the biofilm. Peripheral microorganisms such as Myxococcales, a rapid EPS producer, appear to have contributed to the recovery and stabilization of the biofilm.}, } @article {pmid28168306, year = {2017}, author = {Van Wyk, N and Navarro, D and Blaise, M and Berrin, JG and Henrissat, B and Drancourt, M and Kremer, L}, title = {Characterization of a mycobacterial cellulase and its impact on biofilm- and drug-induced cellulose production.}, journal = {Glycobiology}, volume = {27}, number = {5}, pages = {392-399}, doi = {10.1093/glycob/cwx014}, pmid = {28168306}, issn = {1460-2423}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Cellulase/*chemistry/metabolism ; Cellulose/biosynthesis/chemistry/*metabolism ; Chromatography ; Gene Expression Regulation, Enzymologic/drug effects ; Mycobacterium smegmatis/*enzymology ; Mycobacterium tuberculosis/enzymology ; Rifampin/pharmacology ; }, abstract = {It was recently shown that Mycobacterium tuberculosis produces cellulose which forms an integral part of its extracellular polymeric substances within a biofilm set-up. Using Mycobacterium smegmatis as a proxy model organism, we demonstrate that M. smegmatis biofilms treated with purified MSMEG_6752 releases the main cellulose degradation-product (cellobiose), detected by using ionic chromatography, suggesting that MSMEG_6752 encodes a cellulase. Its overexpression in M. smegmatis prevents spontaneous biofilm formation. Moreover, the method reported here allowed detecting cellobiose when M. smegmatis cultures were exposed to a subinhibitory dose of rifampicin. Overall, this study highlights the role of the MSMEG_6752 in managing cellulose production induced during biofilm formation and antibiotic stress response.}, } @article {pmid28167931, year = {2017}, author = {Dotto, C and Lombarte Serrat, A and Cattelan, N and Barbagelata, MS and Yantorno, OM and Sordelli, DO and Ehling-Schulz, M and Grunert, T and Buzzola, FR}, title = {The Active Component of Aspirin, Salicylic Acid, Promotes Staphylococcus aureus Biofilm Formation in a PIA-dependent Manner.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {4}, pmid = {28167931}, issn = {1664-302X}, abstract = {Aspirin has provided clear benefits to human health. But salicylic acid (SAL) -the main aspirin biometabolite- exerts several effects on eukaryote and prokaryote cells. SAL can affect, for instance, the expression of Staphylococcus aureus virulence factors. SAL can also form complexes with iron cations and it has been shown that different iron chelating molecules diminished the formation of S. aureus biofilm. The aim of this study was to elucidate whether the iron content limitation caused by SAL can modify the S. aureus metabolism and/or metabolic regulators thus changing the expression of the main polysaccharides involved in biofilm formation. The exposure of biofilm to 2 mM SAL induced a 27% reduction in the intracellular free Fe[2+] concentration compared with the controls. In addition, SAL depleted 23% of the available free Fe[2+] cation in culture media. These moderate iron-limited conditions promoted an intensification of biofilms formed by strain Newman and by S. aureus clinical isolates related to the USA300 and USA100 clones. The slight decrease in iron bioavailability generated by SAL was enough to induce the increase of PIA expression in biofilms formed by methicillin-resistant as well as methicillin-sensitive S. aureus strains. S. aureus did not produce capsular polysaccharide (CP) when it was forming biofilms under any of the experimental conditions tested. Furthermore, SAL diminished aconitase activity and stimulated the lactic fermentation pathway in bacteria forming biofilms. The polysaccharide composition of S. aureus biofilms was examined and FTIR spectroscopic analysis revealed a clear impact of SAL in a codY-dependent manner. Moreover, SAL negatively affected codY transcription in mature biofilms thus relieving the CodY repression of the ica operon. Treatment of mice with SAL induced a significant increase of S aureus colonization. It is suggested that the elevated PIA expression induced by SAL might be responsible for the high nasal colonization observed in mice. SAL-induced biofilms may contribute to S. aureus infection persistence in vegetarian individuals as well as in patients that frequently consume aspirin.}, } @article {pmid28167929, year = {2016}, author = {Gloag, ES and Elbadawi, C and Zachreson, CJ and Aharonovich, I and Toth, M and Charles, IG and Turnbull, L and Whitchurch, CB}, title = {Micro-Patterned Surfaces That Exploit Stigmergy to Inhibit Biofilm Expansion.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {2157}, pmid = {28167929}, issn = {1664-302X}, abstract = {Twitching motility is a mode of surface translocation that is mediated by the extension and retraction of type IV pili and which, depending on the conditions, enables migration of individual cells or can manifest as a complex multicellular collective behavior that leads to biofilm expansion. When twitching motility occurs at the interface of an abiotic surface and solidified nutrient media, it can lead to the emergence of extensive self-organized patterns of interconnected trails that form as a consequence of the actively migrating bacteria forging a furrow network in the substratum beneath the expanding biofilm. These furrows appear to direct bacterial movements much in the same way that roads and footpaths coordinate motor vehicle and human pedestrian traffic. Self-organizing systems such as these can be accounted for by the concept of stigmergy which describes self-organization that emerges through indirect communication via persistent signals within the environment. Many bacterial communities are able to actively migrate across solid and semi-solid surfaces through complex multicellular collective behaviors such as twitching motility and flagella-mediated swarming motility. Here, we have examined the potential of exploiting the stigmergic behavior of furrow-mediated trail following as a means of controlling bacterial biofilm expansion along abiotic surfaces. We found that incorporation of a series of parallel micro-fabricated furrows significantly impeded active biofilm expansion by Pseudomonas aeruginosa and Proteus vulgaris. We observed that in both cases bacterial movements tended to be directed along the furrows. We also observed that narrow furrows were most effective at disrupting biofilm expansion as they impeded the ability of cells to self-organize into multicellular assemblies required for escape from the furrows and migration into new territory. Our results suggest that the implementation of micro-fabricated furrows that exploit stigmergy may be a novel approach to impeding active biofilm expansion across abiotic surfaces such as those used in medical and industrial settings.}, } @article {pmid28167385, year = {2017}, author = {Mohanakrishna, G and Butti, SK and Kannaiah Goud, R and Venkata Mohan, S}, title = {Spatiometabolic stratification of anoxic biofilm in prototype bioelectrogenic system.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {115}, number = {}, pages = {11-18}, doi = {10.1016/j.bioelechem.2017.01.002}, pmid = {28167385}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/microbiology ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Catalysis ; Electrodes ; Equipment Design ; Microbial Consortia/genetics/*physiology ; Oxygen ; Proteobacteria ; Waste Disposal, Fluid/*methods ; Wastewater ; }, abstract = {A prototype bio-catalyzed electrogenic system integrated with a biological treatment process (SBR-BET) was evaluated to study specific function of anoxic condition on the electrogenic activity. A multiphasic approach was employed, where the influence of DO on bio-electrogenic activity was optimized initially, later optimal anode to cathode inter-electrode distance was enumerated. Amongst the four electrode distances evaluated, 2cm showed higher power output. Bioelectrokinetics analysis was used to validate the system performance with the experimental variation studied. The redox behavior showed an increase in cathodic catalytic activity with an increase in the inter-electrode distance. Spatiometabolic distribution depicted the microbial stratification on the anode. Electrochemically active bacteria present on the anode surface (inner and outer layers of biofilms) showed relatively uniform diversity compared with the suspension culture.}, } @article {pmid28165539, year = {2017}, author = {Zumstein, V and Betschart, P and Albrich, WC and Buhmann, MT and Ren, Q and Schmid, HP and Abt, D}, title = {Biofilm formation on ureteral stents - Incidence, clinical impact, and prevention.}, journal = {Swiss medical weekly}, volume = {147}, number = {}, pages = {w14408}, doi = {10.4414/smw.2017.14408}, pmid = {28165539}, issn = {1424-3997}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Fluoroquinolones/therapeutic use ; Humans ; Incidence ; Morbidity ; Stents/*adverse effects/microbiology ; *Ureter/microbiology ; Ureteral Obstruction/*complications/diagnosis/drug therapy ; Urinary Tract Infections/etiology ; }, abstract = {Ureteral stents are a simple, minimally invasive method of maintaining ureteral drainage to assure renal function, treat pain caused by ureteral obstruction and avoid external or visible devices. Ureteral stenting is, however, associated with a clear side-effect profile, including irritation on voiding, pain and haematuria. Complications such as stent dysfunction and clinically significant urinary tract infections are also regularly observed. Although this has not yet been thoroughly researched, it appears that biofilm formation on ureteral stents plays a key role in the associated morbidity. In this review, we summarise the current evidence and identify areas that should be further studied to reduce the morbidity associated with ureteral stenting.}, } @article {pmid28163702, year = {2017}, author = {Talagrand-Reboul, E and Jumas-Bilak, E and Lamy, B}, title = {The Social Life of Aeromonas through Biofilm and Quorum Sensing Systems.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {37}, pmid = {28163702}, issn = {1664-302X}, abstract = {Bacteria of the genus Aeromonas display multicellular behaviors herein referred to as "social life". Since the 1990s, interest has grown in cell-to-cell communication through quorum sensing signals and biofilm formation. As they are interconnected, these two self-organizing systems deserve to be considered together for a fresh perspective on the natural history and lifestyles of aeromonads. In this review, we focus on the multicellular behaviors of Aeromonas, i.e., its social life. First, we review and discuss the available knowledge at the molecular and cellular levels for biofilm and quorum sensing. We then discuss the complex, subtle, and nested interconnections between the two systems. Finally, we focus on the aeromonad multicellular coordinated behaviors involved in heterotrophy and virulence that represent technological opportunities and applied research challenges.}, } @article {pmid28161897, year = {2017}, author = {Sousa, BC and Gomes, FA and Ferreira, CM and Rocha, MMNP and Barros, EB and Albuquerque, DS}, title = {Persistent extra-radicular bacterial biofilm in endodontically treated human teeth: scanning electron microscopy analysis after apical surgery.}, journal = {Microscopy research and technique}, volume = {80}, number = {6}, pages = {662-667}, doi = {10.1002/jemt.22847}, pmid = {28161897}, issn = {1097-0029}, mesh = {Biofilms/*growth & development ; *Dental Restoration Failure ; Humans ; Microscopy, Electron, Scanning/*methods ; Root Canal Preparation/methods ; Root Canal Therapy/*methods ; Tooth Root/*microbiology ; }, abstract = {Biofilms are the main cause of endodontic failures. Even the best executed endodontic treatment can fail, when the infection is resistant to treatment or when it is located in inaccessible areas, such as the external surface of the root apex. The purpose of this study was to evaluate, by scanning electron microscopy, the presence of bacterial biofilm on endodontically treated teeth considered clinical failures and suitable for apical surgery. Root apices were collected from 20 teeth undergoing apical surgery and one negative control and analyzed under SEM. Digital photomicrographs of the root apices of 21 specimens at different magnifications were taken. Data were analyzed using descriptive statistics. Apical biofilms were observed in 100% of root canal treatments considered endodontic failure. Topographical analysis of the root apices revealed areas of resorption, microcracks, and apical foramina in 90%, 80%, and 50% of cases, respectively. Within the limits of this study, it can be concluded that endodontic failures present bacterial biofilm in areas inaccessible to conventional endodontic treatment, such as the external surfaces of the root apex.}, } @article {pmid28161291, year = {2017}, author = {Rajasekaran, G and Kim, EY and Shin, SY}, title = {LL-37-derived membrane-active FK-13 analogs possessing cell selectivity, anti-biofilm activity and synergy with chloramphenicol and anti-inflammatory activity.}, journal = {Biochimica et biophysica acta. Biomembranes}, volume = {1859}, number = {5}, pages = {722-733}, doi = {10.1016/j.bbamem.2017.01.037}, pmid = {28161291}, issn = {0005-2736}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/*pharmacology ; Anti-Inflammatory Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Biofilms/*drug effects ; Cells, Cultured ; Chloramphenicol/*pharmacology ; Drug Design ; Drug Synergism ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Mice ; Cathelicidins ; }, abstract = {Although the human-derived antimicrobial peptide (AMP) LL-37 has potent antimicrobial and anti-inflammatory activities, its therapeutic application is limited by its low cell selectivity and high production cost due to its large size. To overcome these problems, we tried to develop novel LL-37-derived short α-helical AMPs with improved cell selectivity and without a significant loss of anti-inflammatory activity relative to that of parental LL-37. Using amino acid substitution, we designed and synthesized a series of FK13 analogs based on the sequence of the 13-meric short FK13 peptide (residues 17-29 of LL-37) that has been identified as the region responsible for the antimicrobial activity of LL-37. Among the designed FK13 analogs, FK-13-a1 and FK-13-a7 showed high cell selectivity and retained the anti-inflammatory activity. The therapeutic index (a measure of cell selectivity) of FK-13-a1 and FK-13-a7 was 6.3- and 2.3-fold that of parental LL-37, respectively. Furthermore, FK-13-a1 and FK-13-a7 displayed more potent antimicrobial activity against antibiotic-resistant bacteria including MRSA, MDRPA, and VREF, than did LL-37. In addition, FK-13-a1 and FK-13-a7 exhibited greater synergistic effects with chloramphenicol against MRSA and MDRPA and were more effective anti-biofilm agents against MDRPA than LL-37 was. Moreover, FK-13-a1 and FK-13-a7 maintained their activities in the presence of physiological salts and human serum. SYTOX green uptake, membrane depolarization and killing kinetics revealed that FK13-a1 and FK13-a7 kills microbial cells by permeabilizing the cell membrane and damaging membrane integrity. Taken together, our results suggest that FK13-a1 and FK13-a7 can be developed as novel antimicrobial/anti-inflammatory agents.}, } @article {pmid28160677, year = {2017}, author = {Hodges, A and Fica, Z and Wanlass, J and VanDarlin, J and Sims, R}, title = {Nutrient and suspended solids removal from petrochemical wastewater via microalgal biofilm cultivation.}, journal = {Chemosphere}, volume = {174}, number = {}, pages = {46-48}, doi = {10.1016/j.chemosphere.2017.01.107}, pmid = {28160677}, issn = {1879-1298}, mesh = {Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Biomass ; Geologic Sediments/*chemistry ; Microalgae/growth & development ; Nitrogen/*isolation & purification ; Petroleum/*metabolism ; Phosphorus/*isolation & purification ; Waste Disposal, Fluid/*methods ; Waste Management/methods ; Wastewater/*chemistry ; }, abstract = {Wastewater derived from petroleum refining currently accounts for 33.6 million barrels per day globally. Few wastewater treatment strategies exist to produce value-added products from petroleum refining wastewater. In this study, mixed culture microalgal biofilm-based treatment of petroleum refining wastewater using rotating algae biofilm reactors (RABRs) was compared with suspended-growth open pond lagoon reactors for removal of nutrients and suspended solids. Triplicate reactors were operated for 12 weeks and were continuously fed with petroleum refining wastewater. Effluent wastewater was monitored for nitrogen, phosphorus, total suspended solids (TSS), and chemical oxygen demand (COD). RABR treatment demonstrated a statistically significant increase in removal of nutrients and suspended solids, and increase in biomass productivity, compared to the open pond lagoon treatment. These trends translate to a greater potential for the production of biomass-based fuels, feed, and fertilizer as value-added products. This study is the first demonstration of the cultivation of mixed culture biofilm microalgae on petroleum refining wastewater for the dual purposes of treatment and biomass production.}, } @article {pmid28160675, year = {2017}, author = {Azari, M and Walter, U and Rekers, V and Gu, JD and Denecke, M}, title = {More than a decade of experience of landfill leachate treatment with a full-scale anammox plant combining activated sludge and activated carbon biofilm.}, journal = {Chemosphere}, volume = {174}, number = {}, pages = {117-126}, doi = {10.1016/j.chemosphere.2017.01.123}, pmid = {28160675}, issn = {1879-1298}, mesh = {Ammonium Compounds/*isolation & purification/metabolism ; Bacteria/*metabolism ; Biofilms/*growth & development ; Biomass ; Bioreactors/microbiology ; Charcoal/*chemistry ; Oxidation-Reduction ; Sewage/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; Water Pollutants, Chemical/analysis/*isolation & purification ; }, abstract = {The performance of biological treatment for high ammonium removal from landfill leachate has been demonstrated. The plant was upgraded combining the activated sludge process followed by activated carbon reactor. Based on a long-term analysis of data collected from 2006 to 2015, the average total nitrogen removal efficiency of 94% was achieved for wastewaters with a C: N ratio varying from 1 to 5 kg-COD kg-TN[-1]. But without the presence of activated carbon reactor, the average of biological removal efficiency for total nitrogen was only 82% ± 6% for the activated sludge stage. It means that up to 20% of the nitrogen in the influent can only be eliminated by microorganisms attached to granular activated carbon. After upgrades of the plant, the energy efficiency showed a reduction in the specific energy demand from 1.6 to less than 0.2 kWh m[-3]. Methanol consumption and sludge production was reduced by 91% and 96%, respectively. Fluorescent in situ Hybridization was used for microbial diversity analysis on floccular sludge and granular biofilm samples. Anaerobic ammonium oxidation (anammox) bacteria and nitrifiers were detected and Candidatus Scalindua was found in two forms of flocs and biofilms. Due to stochastic risk assessment based on the long-term data analysis given in this research, the treatment criteria were achieved and the combination of granular activated carbon biofilm process and activated sludge can be a novel and sought approach to better enrich anammox biomass for full-scale treatment applications to reduce operating costs and promote nutrient removal stability and efficiency.}, } @article {pmid28160658, year = {2017}, author = {Wei, D and Zhang, K and Ngo, HH and Guo, W and Wang, S and Li, J and Han, F and Du, B and Wei, Q}, title = {Nitrogen removal via nitrite in a partial nitrification sequencing batch biofilm reactor treating high strength ammonia wastewater and its greenhouse gas emission.}, journal = {Bioresource technology}, volume = {230}, number = {}, pages = {49-55}, doi = {10.1016/j.biortech.2017.01.033}, pmid = {28160658}, issn = {1873-2976}, mesh = {Ammonia/*isolation & purification ; Batch Cell Culture Techniques ; *Biofilms ; Biopolymers/analysis ; Bioreactors/*microbiology ; Carbon Dioxide/analysis ; *Greenhouse Effect ; Humic Substances ; *Nitrification ; Nitrites/*metabolism ; Nitrogen/*isolation & purification ; Nitrogen Dioxide/analysis ; Spectrometry, Fluorescence ; Time Factors ; Wastewater/*chemistry ; Water Purification/*methods ; }, abstract = {In present study, the feasibility of partial nitrification (PN) process achievement and its greenhouse gas emission were evaluated in a sequencing batch biofilm reactor (SBBR). After 90days' operation, the average effluent NH4[+]-N removal efficiency and nitrite accumulation rate of PN-SBBR were high of 98.2% and 87.6%, respectively. Both polysaccharide and protein contents were reduced in loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) during the achievement of PN-biofilm. Excitation-emission matrix spectra implied that aromatic protein-like, tryptophan protein-like and humic acid-like substances were the main compositions of both kinds of EPS in seed sludge and PN-biofilm. According to typical cycle, the emission rate of CO2 had a much higher value than that of N2O, and their total amounts per cycle were 67.7 and 16.5mg, respectively. Free ammonia (FA) played a significant role on the inhibition activity of nitrite-oxidizing bacteria and the occurrence of nitrite accumulation.}, } @article {pmid28159990, year = {2017}, author = {Ramos, LS and Oliveira, SSC and Souto, XM and Branquinha, MH and Santos, ALS}, title = {Planktonic growth and biofilm formation profiles in Candida haemulonii species complex.}, journal = {Medical mycology}, volume = {55}, number = {7}, pages = {785-789}, doi = {10.1093/mmy/myx005}, pmid = {28159990}, issn = {1460-2709}, mesh = {Biofilms/*growth & development ; Biomass ; Brazil ; Candida/growth & development/isolation & purification/pathogenicity/*physiology ; Candidiasis/microbiology ; Culture Media/chemistry ; Gentian Violet/metabolism ; Humans ; Microbiological Techniques ; Oxidation-Reduction ; Staining and Labeling ; Temperature ; Tetrazolium Salts/metabolism ; Time Factors ; }, abstract = {Candida haemulonii species complex have emerged as multidrug-resistant yeasts able to cause fungemia worldwide. However, very little is known regarding their physiology and virulence factors. In this context, planktonic growth and biofilm formation of Brazilian clinical isolates of Candida haemulonii (n = 5), Candida duobushaemulonii (n = 4), and Candida haemulonii var. vulnera (n = 3) were reported. Overall, the fungal planktonic growth curves in Sabouraud dextrose broth reached the exponential phase in 48 h at 37°C. All the clinical isolates formed biofilm on polystyrene in a time-dependent event, as judged by the parameters evaluated: biomass (crystal violet staining), metabolic activity (XTT reduction), and extracellular matrix (safranin incorporation). No statistically significant differences were observed when the average measurements among the three Candida species were compared regarding both planktonic and biofilm lifestyles; however, typical isolate-specific differences were clearly noticed in fungal growth kinetics.}, } @article {pmid28159787, year = {2017}, author = {Bassi, D and Cappa, F and Gazzola, S and Orrù, L and Cocconcelli, PS}, title = {Biofilm Formation on Stainless Steel by Streptococcus thermophilus UC8547 in Milk Environments Is Mediated by the Proteinase PrtS.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {8}, pages = {}, pmid = {28159787}, issn = {1098-5336}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cell Wall/metabolism ; Genome, Bacterial ; Genomic Islands ; Milk/chemistry/*microbiology ; Milk Proteins/metabolism ; Serine Endopeptidases/genetics/*metabolism ; *Stainless Steel ; Streptococcus thermophilus/*enzymology/genetics/growth & development/physiology ; }, abstract = {In Streptococcus thermophilus, gene transfer events and loss of ancestral traits over the years contribute to its high level of adaptation to milk environments. Biofilm formation capacity, a phenotype that is lost in the majority of strains, plays a role in persistence in dairy environments, such as milk pasteurization and cheese manufacturing plants. To investigate this property, we have studied S. thermophilus UC8547, a fast-acidifying dairy starter culture selected for its high capacity to form biofilm on stainless steel under environmental conditions resembling the dairy environment. Using a dynamic flow cell apparatus, it was shown that S. thermophilus UC8547 biofilm formation on stainless steel depends on the presence of milk proteins. From this strain, which harbors the prtS gene for the cell wall protease and shows an aggregative phenotype, spontaneous mutants with impaired biofilm capacity can be isolated at high frequency. These mutants lack the PrtS expendable island, as confirmed by comparison of the genome sequence of UC8547Δ3 with that of the parent strain. The prtS island excision occurs between two 26-bp direct repeats located in the two copies of the ISSth1 flanking this genomic island. The central role of PrtS was confirmed by analyzing the derivative strain UC8547Δ16, whose prtS gene was interrupted by an insertional mutation, thereby making it incapable of biofilm formation. PrtS, acting as a binding substance between the milk proteins adhered to stainless steel and S. thermophilus cell envelopes, mediates biofilm formation in dairy environments. This feature provides S. thermophilus with an ecological benefit for its survival and persistence in this environment.IMPORTANCE The increased persistence of S. thermophilus biofilm has consequences in the dairy environment: if, on the one hand, the release of this microorganism from biofilm can promote the fermentation of artisanal cheeses, under industrial conditions it may lead to undesirable contamination of dairy products. The study of the molecular mechanism driving S. thermophilus biofilm formation provides increased knowledge on how an ancestral trait affects relevant phenotypes, such as persistence in the environment and efficiency of growth in milk. This study provides insight into the genetic factors affecting biofilm formation at dairy plants.}, } @article {pmid28158975, year = {2017}, author = {Johnson, WH and Douglas, MR and Lewis, JA and Stuecker, TN and Carbonero, FG and Austin, BJ and Evans-White, MA and Entrekin, SA and Douglas, ME}, title = {Do biofilm communities respond to the chemical signatures of fracking? A test involving streams in North-central Arkansas.}, journal = {BMC microbiology}, volume = {17}, number = {1}, pages = {29}, pmid = {28158975}, issn = {1471-2180}, mesh = {Agriculture ; Arkansas ; Bacteria/classification/genetics/isolation & purification/metabolism ; Biodiversity ; *Biofilms ; DNA, Bacterial ; Ecology ; Ecosystem ; *Environmental Monitoring ; Geographic Mapping ; Groundwater/chemistry/microbiology ; *Hydraulic Fracking ; Hydrology ; Microbiota ; Natural Gas ; Nitrogen/analysis ; Oil and Gas Industry ; Phosphorous Acids/analysis ; RNA, Ribosomal, 16S/genetics ; Rivers/*chemistry/microbiology ; Urbanization ; Water Pollutants, Chemical/*analysis ; Water Pollution ; }, abstract = {BACKGROUND: Unconventional natural gas (UNG) extraction (fracking) is ongoing in 29 North American shale basins (20 states), with ~6000 wells found within the Fayetteville shale (north-central Arkansas). If the chemical signature of fracking is detectable in streams, it can be employed to bookmark potential impacts. We evaluated benthic biofilm community composition as a proxy for stream chemistry so as to segregate anthropogenic signatures in eight Arkansas River catchments. In doing so, we tested the hypothesis that fracking characteristics in study streams are statistically distinguishable from those produced by agriculture or urbanization.

RESULTS: Four tributary catchments had UNG-wells significantly more dense and near to our sampling sites and were grouped as 'potentially-impacted catchment zones' (PICZ). Four others were characterized by significantly larger forested area with greater slope and elevation but reduced pasture, and were classified as 'minimally-impacted' (MICZ). Overall, 46 bacterial phyla/141 classes were identified, with 24 phyla (52%) and 54 classes (38%) across all samples. PICZ-sites were ecologically more variable than MICZ-sites, with significantly greater nutrient levels (total nitrogen, total phosphorous), and elevated Cyanobacteria as bioindicators that tracked these conditions. PICZ-sites also exhibited elevated conductance (a correlate of increased ion concentration) and depressed salt-intolerant Spartobacteria, suggesting the presence of brine as a fracking effect. Biofilm communities at PICZ-sites were significantly less variable than those at MICZ-sites.

CONCLUSIONS: Study streams differed by Group according to morphology, land use, and water chemistry but not in biofilm community structure. Those at PICZ-sites covaried according to anthropogenic impact, and were qualitatively similar to communities found at sites disturbed by fracking. The hypothesis that fracking signatures in study streams are distinguishable from those produced by other anthropogenic effects was statistically rejected. Instead, alterations in biofilm community composition, as induced by fracking, may be less specific than initially predicted, and thus more easily confounded by agriculture and urbanization effects (among others). Study streams must be carefully categorized with regard to the magnitude and extent of anthropogenic impacts. They must also be segregated with statistical confidence (as herein) before fracking impacts are monitored.}, } @article {pmid28158695, year = {2017}, author = {Yoshida, K and Toyofuku, M and Obana, N and Nomura, N}, title = {Biofilm formation by Paracoccus denitrificans requires a type I secretion system-dependent adhesin BapA.}, journal = {FEMS microbiology letters}, volume = {364}, number = {4}, pages = {}, doi = {10.1093/femsle/fnx029}, pmid = {28158695}, issn = {1574-6968}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Hydrophobic and Hydrophilic Interactions ; Paracoccus denitrificans/metabolism/*physiology ; Type I Secretion Systems/*metabolism ; }, abstract = {Paracoccus denitrificans is a non-swimming Gram-negative bacterium, with versatile respiration capability which has remarkable potentials for bioremediation, especially in water treatment. Although biofilms are important in water treatment systems, the genetic mechanisms underlying the cellular adherence and biofilm formation of this bacterium remain unknown. We show that P. denitrificans forms a thin biofilm on surfaces at the air-liquid interface under static conditions. The initial step of biofilm formation requires a biofilm-associated protein BapA, which we identified by transposon mutant screening. BapA contains a unique sequence of dipeptide repeats of aspartate and alanine. Our data indicate that BapA is translocated to the extracellular milieu by a type 1 secretion system, where it enables the cells to attach to the substratum. Furthermore, superresolution microscopy shows that BapA is localized on the cell surface, which alters the cell surface hydrophobicity. Our results show a crucial role of BapA that promotes the adhesion and biofilm formation of P. denitrificans.}, } @article {pmid28158402, year = {2017}, author = {Rath, H and Feng, D and Neuweiler, I and Stumpp, NS and Nackenhorst, U and Stiesch, M}, title = {Biofilm formation by the oral pioneer colonizer Streptococcus gordonii: an experimental and numerical study.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {3}, pages = {}, doi = {10.1093/femsec/fix010}, pmid = {28158402}, issn = {1574-6941}, mesh = {*Biofilms ; Dental Implants/adverse effects/*microbiology ; Humans ; Mouth/*microbiology ; Streptococcal Infections/etiology/*microbiology ; Streptococcus gordonii/genetics/growth & development/*physiology ; }, abstract = {For decades, extensive research efforts have been conducted to improve the functionality and stability of implants. Especially in dentistry, implant treatment has become a standard medical practice. The treatment restores full dental functionality, helping patients to maintain high quality of life. However, about 10% of the patients suffer from early and late device failure due to peri-implantitis, an inflammatory disease of the tissues surrounding the implant. Peri-implantitis is caused by progressive microbial colonization of the device surface and the formation of microbial communities, so-called biofilms. This infection can ultimately lead to implant failure. The causative agents for the inflammatory disease, periodontal pathogenic biofilms, have already been extensively studied, but are still not completely understood. As numerical simulations will have the potential to predict oral biofilm formation precisely in the future, for the first time, this study aimed to analyze Streptococcus gordonii biofilms by combining experimental studies and numerical simulation. The study demonstrated that numerical simulation was able to precisely model the influence of different nutrient concentration and spatial distribution of active and inactive biomass of the biofilm in comparison with the experimental data. This model may provide a less time-consuming method for the future investigation of any bacterial biofilm.}, } @article {pmid28158292, year = {2017}, author = {Pan, S and Liu, Y and Zhang, L and Li, S and Zhang, Y and Liu, J and Wang, C and Xiao, S}, title = {Profiling of subgingival plaque biofilm microbiota in adolescents after completion of orthodontic therapy.}, journal = {PloS one}, volume = {12}, number = {2}, pages = {e0171550}, pmid = {28158292}, issn = {1932-6203}, mesh = {Adolescent ; Bacteria/*isolation & purification ; *Biofilms ; Case-Control Studies ; Dental Plaque/*microbiology ; Female ; Gingiva/microbiology ; Humans ; Male ; *Microbiota ; Orthodontic Brackets/*microbiology ; Real-Time Polymerase Chain Reaction ; }, abstract = {BACKGROUND: Fixed orthodontic treatment is the most common method for malocclusion but has the potential risk of periodontal complication with unclear outcomes of whether microbiologic and clinical changes could be reversible in adolescents after orthodontic therapy.

METHODS: Twenty adolescents with orthodontic treatment were enrolled in the study as the case group at end of the therapy, while 19 periodontally healthy adolescents were involved in the control group. At baseline (T0), clinical parameters including gingival index, probing depth and sulcus bleeding index were tested, and subgingival plaque samples were collected from the lower incisors. The counts of A. actinomycetemcomitans, P. gingivalis, P. intermedia, T. forsythia and total bacteria were determined by real-time PCR. All parameters were reassessed after 1 month (T1) and 3 months (T2) in the case group and compared with that of the controls.

RESULTS: At baseline (T0), clinical parameters (including GI, PD, SBI) of the test sites in the case group were significantly higher than that of the control group (P<0.05 or P<0.01). At 3 months (T2), no differences were noticed in GI and SBI between two groups. The prevalence and counts of periodontopathogens tend to be normal (P>0.05), while PD and the amount of P.intermedia were still significantly higher compared with that of the control group (P<0.05 or P<0.01).

CONCLUSION: After removal of appliances, the periodontal changes induced by orthodontic therapy are only partially reversible at 3 months after removal.}, } @article {pmid28155911, year = {2017}, author = {Totani, T and Nishiuchi, Y and Tateishi, Y and Yoshida, Y and Kitanaka, H and Niki, M and Kaneko, Y and Matsumoto, S}, title = {Effects of nutritional and ambient oxygen condition on biofilm formation in Mycobacterium avium subsp. hominissuis via altered glycolipid expression.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {41775}, pmid = {28155911}, issn = {2045-2322}, mesh = {Biofilms/drug effects/*growth & development ; Disinfectants/pharmacology ; Environment ; *Environmental Microbiology ; Glycolipids/*metabolism ; Humans ; Hypoxia ; Mutation ; Mycobacterium Infections, Nontuberculous/*microbiology ; Mycobacterium avium/drug effects/*physiology/ultrastructure ; *Nutritional Physiological Phenomena ; *Oxygen Consumption ; Phenotype ; }, abstract = {Mycobacterium avium subsp. hominissuis (MAH) is the major causative agent of nontuberculous mycobacteriosis, the representative case of environment-related infectious diseases the incidence of which is increasing in industrialized countries. MAH is found in biofilm in drinking water distribution system and residential environments. We investigated the effect of gaseous and nutritional conditions, and the role of glycopeptidolipids (GPLs) on biofilm-like pellicle formation in MAH. Pellicle formation was observed under 5% oxygen in Middlebrook 7H9 broth containing 0.2% glycerol and 10% albumin-dextrose-catalase enrichment but not under normoxia or in nutrient-poor media. An analysis of 17 environmental isolates revealed that hypoxia (5% oxygen) preferentially enhanced pellicle formation both in plastic plates and in glass tubes, compared with hypercapnia (5% carbon dioxide). Wild-type strains (WT) developed much thicker pellicles than GPL-deficient rough mutants (RM). WT bacterial cells distributed randomly and individually in contrast to that RM cells positioned linearly in a definite order. Exogenous supplementation of GPLs thickened the pellicles of RM, resulting in a similar morphological pattern to WT. These data suggest a significant implication of eutrophication and hypoxia in biofilm-like pellicle formation, and a functional role of GPLs on development of pellicles in MAH.}, } @article {pmid28155334, year = {2017}, author = {Manoharan, RK and Lee, JH and Kim, YG and Kim, SI and Lee, J}, title = {Inhibitory effects of the essential oils α-longipinene and linalool on biofilm formation and hyphal growth of Candida albicans.}, journal = {Biofouling}, volume = {33}, number = {2}, pages = {143-155}, doi = {10.1080/08927014.2017.1280731}, pmid = {28155334}, issn = {1029-2454}, mesh = {Acyclic Monoterpenes ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/pathogenicity/physiology ; Humans ; Hyphae/*drug effects/growth & development ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Oils, Volatile/*pharmacology ; Sesquiterpenes/*pharmacology ; Virulence/drug effects ; }, abstract = {Candida albicans is one of the most common fungal pathogens, and causes systemic and invasive infections in humans. C. albicans biofilms are composed of yeast and hyphal and pseudohyphal elements, and the transition of yeast to the hyphal stage could be a virulence factor. In this study, diverse essential oils were initially investigated for anti-biofilm activity against C. albicans strains, and cascarilla bark oil and helichrysum oil and their components α-longipinene (a major constituent of both) and linalool were found to markedly inhibit biofilm formation without affecting planktonic cell growth. Moreover, α-longipinene and linalool were found to synergistically reduce biofilm formation. Notably, treatments with cascarilla bark oil, helichrysum oil, α-longipinene, or linalool clearly inhibited hyphal formation, and this appeared to be largely responsible for their anti-biofilm effect. Furthermore, the two essential oils, α-longipinene and linalool, reduced C. albicans virulence in Caenorhabditis elegans.}, } @article {pmid28155216, year = {2017}, author = {Dutta Sinha, S and Chatterjee, S and Maiti, PK and Tarafdar, S and Moulik, SP}, title = {Evaluation of the role of substrate and albumin on Pseudomonas aeruginosa biofilm morphology through FESEM and FTIR studies on polymeric biomaterials.}, journal = {Progress in biomaterials}, volume = {6}, number = {1-2}, pages = {27-38}, pmid = {28155216}, issn = {2194-0509}, abstract = {Bacterial biofilms pose the greatest challenge to implant surgeries leading to device-related infections and implant failure. Our present study aims at monitoring the variation in the biofilm architecture of a clinically isolated strain and ATCC 27853 strain of Pseudomonas aeruginosa on two polymeric biomaterials, used in implants. The perspective of our study is to recognize the potential of these two biomaterials to create biofilm infections and develop the understanding regarding their limitations of use and handle patients with this deeper insight. The final goal, however, is an accurate interpretation of substrate-microbe interactions in the two biomaterials, which will provide us the knowledge of possible surface modifications to develop of an efficacious anti-biofilm therapy for deterring implant infections. The reference strain ATCC 27853 and a clinical isolate of P. aeruginosa collected from urinary catheters of patients suffering from urinary tract infections, have been used as microbes while clinical grades of polypropylene and high density polyethylene, have been used as 'substrates' for biofilm growth. The variation in the nature of the 'substrate' and 'conditioning layer' of BSA have been found to affect the biofilm architecture as well as the physiology of the biofilm-forming bacteria, accompanied by an alteration in the nature and volume of EPS (extracellular polysaccharide) matrices.}, } @article {pmid28152096, year = {2017}, author = {Kim, DJ and Lee, MW and Choi, JS and Lee, SG and Park, JY and Kim, SW}, title = {Inhibitory activity of hinokitiol against biofilm formation in fluconazole-resistant Candida species.}, journal = {PloS one}, volume = {12}, number = {2}, pages = {e0171244}, pmid = {28152096}, issn = {1932-6203}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects ; Candida albicans/drug effects ; Candida glabrata/drug effects ; Candida tropicalis/drug effects ; Drug Resistance, Fungal ; Fluconazole/pharmacology ; Gene Expression Regulation, Fungal/drug effects ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Real-Time Polymerase Chain Reaction ; Tropolone/*analogs & derivatives/pharmacology ; }, abstract = {The aim of this study was to investigate the ability of hinokitiol to inhibit the formation of Candida biofilms. Biofilm inhibition was evaluated by quantification of the biofilm metabolic activity with XTT assay. Hinokitiol efficiently prevented biofilm formation in both fluconazole-susceptible and fluconazole-resistant strains of Candida species. We determined the expression levels of specific genes previously implicated in biofilm development of C. albicans cells by real-time RT-PCR. The expression levels of genes associated with adhesion process, HWP1 and ALS3, were downregulated by hinokitiol. Transcript levels of UME6 and HGC1, responsible for long-term hyphal maintenance, were also decreased by hinokitiol. The expression level of CYR1, which encodes the component of signaling pathway of hyphal formation-cAMP-PKA was suppressed by hinokitiol. Its upstream general regulator RAS1 was also suppressed by hinokitiol. These results indicate that hinokitiol may have therapeutic potential in the treatment and prevention of biofilm-associated Candida infections.}, } @article {pmid28150937, year = {2017}, author = {Chamsaz, EA and Mankoci, S and Barton, HA and Joy, A}, title = {Nontoxic Cationic Coumarin Polyester Coatings Prevent Pseudomonas aeruginosa Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {9}, number = {8}, pages = {6704-6711}, doi = {10.1021/acsami.6b12610}, pmid = {28150937}, issn = {1944-8252}, mesh = {Animals ; Anti-Bacterial Agents ; Biofilms ; Coated Materials, Biocompatible ; Coumarins ; Humans ; Polyesters ; *Pseudomonas aeruginosa ; }, abstract = {The rapid increase in bacterial infections and antimicrobial resistance is a growing public health concern. Infections arising from bacterial contamination of surgical tools, medical implants, catheters, and hospital surfaces can potentially be addressed by antimicrobial polymeric coatings. The challenge in developing such polymers for in vivo use is the ability to achieve high antimicrobial efficacy while at the same time being nontoxic to human cells. Although several classes of antimicrobial polymers have been developed, many of them cannot be used in the clinical setting due to their nonselective toxicity toward bacteria and mammalian cells. Here, we demonstrate that coumarin polyesters with cationic pendant groups are very effective against Gram negative Pseudomonas aeruginosa. Coumarin polyesters with pendant cationic amine groups were coated onto glass coverslips and tested for their antimicrobial activity against P. aeruginosa colonization of the surface. The results demonstrate that the cationic coumarin polyester kills the surface attached bacterial cells preventing biofilm formation but does not show any hemolytic activity or discernible toxicity toward mammalian cells. The antimicrobial polyesters described in this work have several advantages desired in antimicrobial coatings such as high antimicrobial activity, low toxicity toward mammalian cells, visualization and ease of synthesis and fabrication, all of which are necessary for translation to the clinic.}, } @article {pmid28150898, year = {2017}, author = {Dos Santos, LF and Biscola, FT and Gonçalves, EM and Guth, BE}, title = {Biofilm formation, invasiveness and colicinogeny in locus of enterocyte and effacement negative O113:H21 Shigatoxigenic Escherichia coli.}, journal = {Journal of applied microbiology}, volume = {122}, number = {4}, pages = {1101-1109}, doi = {10.1111/jam.13409}, pmid = {28150898}, issn = {1365-2672}, mesh = {Animals ; Biofilms/*growth & development ; Caco-2 Cells ; Cell Line ; Colicins/metabolism ; Humans ; Shiga-Toxigenic Escherichia coli/genetics/isolation & purification/*pathogenicity/physiology ; Virulence ; }, abstract = {AIMS: Although Shiga toxins (Stx) are well-established virulence traits of O113:H21 Shigatoxigenic Escherichia coli (STEC) strains, a shortage in the knowledge of other virulence properties that may contribute to pathogenesis may exist in this serotype. This study investigated biofilm, invasiveness and colicinogeny capabilities in O113:H21 STEC isolated in Brazil, mostly from animal reservoirs. A search for genes that were reported to participate in the process of biofilm formation was also performed.

METHODS AND RESULTS: The 34 O113:H21 STEC isolates analysed were assayed for biofilm production in polystyrene microplates. Genes for biofilm were investigated by PCR. Invasion of cell lineages was assessed in gentamicin protection assays and colicinogeny was investigated by phenotypic tests. Fifty per cent of the strains were biofilm formers, and 35% exhibited an invasive behaviour. The pattern of distribution of biofilm-related genes did not correlate with biofilm phenotypes observed, and a high percentage of the investigated strains were able to secrete colicins.

CONCLUSION: Ability to form biofilm, invasiveness and colicinogeny is demonstrated for the first time in a collection of O113:H21 STEC.

The ability to express three additional phenotypes besides Stx production may be a factor influencing the pathogenicity and persistence potential of O113:H21 STEC.}, } @article {pmid28149169, year = {2017}, author = {Rahman, MR and Lou, Z and Yu, F and Wang, P and Wang, H}, title = {Anti-quorum sensing and anti-biofilm activity of Amomum tsaoko (Amommum tsao-ko Crevost et Lemarie) on foodborne pathogens.}, journal = {Saudi journal of biological sciences}, volume = {24}, number = {2}, pages = {324-330}, pmid = {28149169}, issn = {1319-562X}, abstract = {Cell-to-cell communication or quorum sensing (QS) leads to biofilm formation and causing other virulence factors which are extreme problems for food safety, biofilm related infectious diseases etc. This study evaluated the anti-QS activity of the Amomum tsaoko extract (0.5-4 mg/ml) by using Chromobacterium violaceum a biosensor strain and biofilm formation by crystal violate assay. Experimental results demonstrated that the overall yield of Amomum tsao-ko extract was 11.33 ± 0.3% (w/w). MIC for Staphylococcus aureus (Gram positive), Salmonella Typhimurium and Pseudomonas aeruginosa (Gram negative) was 1, 2 and 2 mg/ml, respectively. A concentration of 4 mg/ml extract showed highest biofilm inhibition 51.96% on S. Typhimurium when 47.06%, 45.28% were shown by S. aureus, P. aeruginosa respectively. The damage of biofilm architecture was observed by Confocal Laser Scanning Microscopy (CLSM). A level of 44.59% inhibition of violacein production was demonstrated when the dose was 4 mg/ml. Swarming motility inhibition was observed in a dose dependent manner. Taken together, the treatment of A. tsaoko extract can deliver value to food product and medicine by controlling pathogenesis.}, } @article {pmid28148986, year = {2017}, author = {Kalia, VC and Prakash, J and Koul, S and Ray, S}, title = {Simple and Rapid Method for Detecting Biofilm Forming Bacteria.}, journal = {Indian journal of microbiology}, volume = {57}, number = {1}, pages = {109-111}, pmid = {28148986}, issn = {0046-8991}, abstract = {Biofilm forming bacteria play a vital role in causing infectious diseases and for enhancing the efficiency of the bioremediation process through immobilization. Different media and conditions have been reported for detecting biofilm forming bacteria, however, they are not quite rapid. Here, we propose the use of a simple medium which can be used for detecting biofilm former, and also provide a mechanism to regulate the expression of biofilm formation process.}, } @article {pmid28143981, year = {2017}, author = {Yu, L and Hisatsune, J and Hayashi, I and Tatsukawa, N and Sato'o, Y and Mizumachi, E and Kato, F and Hirakawa, H and Pier, GB and Sugai, M}, title = {A Novel Repressor of the ica Locus Discovered in Clinically Isolated Super-Biofilm-Elaborating Staphylococcus aureus.}, journal = {mBio}, volume = {8}, number = {1}, pages = {}, pmid = {28143981}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; Codon, Nonsense ; Gene Deletion ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; *Genetic Loci ; Genome, Bacterial ; Microarray Analysis ; Multigene Family ; Mutant Proteins/genetics/metabolism ; Operon ; Polysaccharides, Bacterial/metabolism ; Repressor Proteins/genetics/*metabolism ; Sequence Analysis, DNA ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*genetics/isolation & purification/*physiology ; }, abstract = {Staphylococcus aureus TF2758 is a clinical isolate from an atheroma and a super-biofilm-elaborating/polysaccharide intercellular adhesin (PIA)/poly-N-acetylglucosamine (PNAG)-overproducing strain (L. Shrestha et al., Microbiol Immunol 60:148-159, 2016, https://doi.org/10.1111/1348-0421.12359). A microarray analysis and DNA genome sequencing were performed to identify the mechanism underlying biofilm overproduction by TF2758. We found high transcriptional expression levels of a 7-gene cluster (satf2580 to satf2586) and the ica operon in TF2758. Within the 7-gene cluster, a putative transcriptional regulator gene designated rob had a nonsense mutation that caused the truncation of the protein. The complementation of TF2758 with rob from FK300, an rsbU-repaired derivative of S. aureus strain NCTC8325-4, significantly decreased biofilm elaboration, suggesting a role for rob in this process. The deletion of rob in non-biofilm-producing FK300 significantly increased biofilm elaboration and PIA/PNAG production. In the search for a gene(s) in the 7-gene cluster for biofilm elaboration controlled by rob, we identified open reading frame (ORF) SAOUHSC_2898 (satf2584). Our results suggest that ORF SAOUHSC_2898 (satf2584) and icaADBC are required for enhanced biofilm elaboration and PIA/PNAG production in the rob deletion mutant. Rob bound to a palindromic sequence within its own promoter region. Furthermore, Rob recognized the TATTT motif within the icaR-icaA intergenic region and bound to a 25-bp DNA stretch containing this motif, which is a critically important short sequence regulating biofilm elaboration in S. aureus Our results strongly suggest that Rob is a long-sought repressor that recognizes and binds to the TATTT motif and is an important regulator of biofilm elaboration through its control of SAOUHSC_2898 (SATF2584) and Ica protein expression in S. aureus IMPORTANCE: During the search for molecular mechanisms underlying biofilm overproduction of Staphylococcus aureus TF2758, we found a putative transcriptional regulator gene designated rob within a 7-gene cluster showing a high transcriptional expression level by microarray analysis. The deletion of rob in non-biofilm-producing FK300, an rsbU-repaired derivative of NCTC8325-4, significantly increased biofilm elaboration and PIA/PNAG production. The search for a gene(s) in the 7-gene cluster for biofilm elaboration controlled by rob identified ORF SAOUHSC_2898. Besides binding to its own promoter region to control ORF SAOUHSC_2898 expression, Rob recognized the TATTT motif within the icaR-icaA intergenic region and bound to a 25-bp DNA stretch containing this motif, which is a critically important short sequence regulating biofilm elaboration in S. aureus Our results strongly suggest that Rob is a long-sought repressor that recognizes and binds to the TATTT motif and is a new important regulator of biofilm elaboration through its control of SAOUHSC_2898 and Ica protein expression in S. aureus.}, } @article {pmid28142193, year = {2017}, author = {Moormeier, DE and Bayles, KW}, title = {Staphylococcus aureus biofilm: a complex developmental organism.}, journal = {Molecular microbiology}, volume = {104}, number = {3}, pages = {365-376}, pmid = {28142193}, issn = {1365-2958}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 AI038901/AI/NIAID NIH HHS/United States ; R01 AI125589/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Staphylococcus aureus/*physiology ; }, abstract = {Chronic biofilm-associated infections caused by Staphylococcus aureus often lead to significant increases in morbidity and mortality, particularly when associated with indwelling medical devices. This has triggered a great deal of research attempting to understand the molecular mechanisms that control S. aureus biofilm formation and the basis for the recalcitrance of these multicellular structures to antibiotic therapy. The purpose of this review is to summarize our current understanding of S. aureus biofilm development, focusing on the description of a newly-defined, five-stage model of biofilm development and the mechanisms required for each stage. Importantly, this model includes an alternate view of the processes involved in microcolony formation in S. aureus and suggests that these structures originate as a result of stochastically regulated metabolic heterogeneity and proliferation within a maturing biofilm population, rather than a subtractive process involving the release of cell clusters from a thick, unstructured biofilm. Importantly, it is proposed that this new model of biofilm development involves the genetically programmed generation of metabolically distinct subpopulations of cells, resulting in an overall population that is better able to adapt to rapidly changing environmental conditions.}, } @article {pmid28141493, year = {2017}, author = {Besingi, RN and Wenderska, IB and Senadheera, DB and Cvitkovitch, DG and Long, JR and Wen, ZT and Brady, LJ}, title = {Functional amyloids in Streptococcus mutans, their use as targets of biofilm inhibition and initial characterization of SMU_63c.}, journal = {Microbiology (Reading, England)}, volume = {163}, number = {4}, pages = {488-501}, pmid = {28141493}, issn = {1465-2080}, support = {T90 DE021990/DE/NIDCR NIH HHS/United States ; R01 DE021789/DE/NIDCR NIH HHS/United States ; R01 DE019783/DE/NIDCR NIH HHS/United States ; R01 DE019452/DE/NIDCR NIH HHS/United States ; R21 DE025348/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/metabolism ; Amyloid/*metabolism ; Antigens, Bacterial/*metabolism ; Bacterial Adhesion ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Extracellular Matrix/metabolism ; Streptococcus mutans/growth & development/*metabolism ; Tannins/pharmacology ; }, abstract = {Amyloids have been identified as functional components of the extracellular matrix of bacterial biofilms. Streptococcus mutans is an established aetiologic agent of dental caries and a biofilm dweller. In addition to the previously identified amyloidogenic adhesin P1 (also known as AgI/II, PAc), we show that the naturally occurring antigen A derivative of S. mutans wall-associated protein A (WapA) and the secreted protein SMU_63c can also form amyloid fibrils. P1, WapA and SMU_63c were found to significantly influence biofilm development and architecture, and all three proteins were shown by immunogold electron microscopy to reside within the fibrillar extracellular matrix of the biofilms. We also showed that SMU_63c functions as a negative regulator of biofilm cell density and genetic competence. In addition, the naturally occurring C-terminal cleavage product of P1, C123 (also known as AgII), was shown to represent the amyloidogenic moiety of this protein. Thus, P1 and WapA both represent sortase substrates that are processed to amyloidogenic truncation derivatives. Our current results suggest a novel mechanism by which certain cell surface adhesins are processed and contribute to the amyloidogenic capability of S. mutans. We further demonstrate that the polyphenolic small molecules tannic acid and epigallocatechin-3-gallate, and the benzoquinone derivative AA-861, which all inhibit amyloid fibrillization of C123 and antigen A in vitro, also inhibit S. mutans biofilm formation via P1- and WapA-dependent mechanisms, indicating that these proteins serve as therapeutic targets of anti-amyloid compounds.}, } @article {pmid28138928, year = {2017}, author = {Shafiei, M and Abdi-Ali, A and Shahcheraghi, F and Vali, H and Shahbani Zahiri, H and Akbari Noghabi, K}, title = {Analysis of Pseudomonas aeruginosa PAO1 Biofilm Protein Profile After Exposure to n-Butanolic Cyclamen coum Extract Alone and in Combination with Ciprofloxacin.}, journal = {Applied biochemistry and biotechnology}, volume = {182}, number = {4}, pages = {1444-1457}, doi = {10.1007/s12010-017-2409-4}, pmid = {28138928}, issn = {1559-0291}, mesh = {Adaptation, Physiological/drug effects ; Amino Acids/metabolism ; Bacterial Proteins/*metabolism ; *Biofilms/drug effects ; Biomass ; Butanols/chemistry ; Carbon/metabolism ; Ciprofloxacin/*pharmacology ; Cyclamen/*chemistry/metabolism ; Drug Synergism ; Fatty Acids/metabolism ; Lipopolysaccharides/metabolism ; Phospholipids/metabolism ; Plant Extracts/*pharmacology ; Pseudomonas aeruginosa/*drug effects/*metabolism/physiology ; }, abstract = {Pseudomonas aeruginosa biofilm-related infections are the major cause of premature death in cystic fibrosis patients. Strategies to induce biofilm dispersal are of interest, because of their potential in preventing biofilm-related infections. Our previous work demonstrated that n-butanolic Cyclamen coum extract with ciprofloxacin could eliminate 1- and 3-day-old P. aeruginosa PAO1 biofilms. To gain new insights into the role of C. coum extract and its synergistic effect with ciprofloxacin in eliminating P. aeruginosa PAO1 biofilms, two-dimensional gel electrophoresis (2-DE) in combination with mass spectrometry-based protein identification were used. Changes in the bacterial protein expression were analyzed when 3-day-old biofilm cells were exposed to the C. coum extract alone and in combination with ciprofloxacin. Proteins involved in alginate biosynthesis, quorum sensing, adaptation/protection, carbohydrate and amino acid metabolism showed a weaker expression in the C. coum extract-ciprofloxacin-treated biofilm cells compared to those in the untreated cells. Interestingly, the proteome of C. coum extract-ciprofloxacin-treated biofilm revealed more resemblance to the planktonic phenotype than to the biofilm phenotype. It appears that saponin extract in combination with ciprofloxacin causes biofilm disruption due to several mechanisms such as motility induction, cell envelope integrity perturbation, stress protein expression reduction, and more importantly, signal transduction perturbation. In conclusion, exposure to a combination of biofilm dispersal such as saponin extract and antimicrobial agents may offer a novel strategy to control preestablished, persistent P. aeruginosa biofilms and biofilm-related infections.}, } @article {pmid28138698, year = {2017}, author = {Sebaa, S and Hizette, N and Boucherit-Otmani, Z and Courtois, P}, title = {Dose‑dependent effect of lysozyme upon Candida albicans biofilm.}, journal = {Molecular medicine reports}, volume = {15}, number = {3}, pages = {1135-1142}, pmid = {28138698}, issn = {1791-3004}, mesh = {Animals ; Biofilms/*drug effects/*growth & development ; Candida albicans/*drug effects/*physiology ; Humans ; Muramidase/*pharmacology ; }, abstract = {The present study investigated the in vitro effect of lysozyme (0-1,000 µg/ml) on Candida albicans (C. albicans) biofilm development. Investigations were conducted on C. albicans ATCC 10231 and on 10 clinical isolates from dentures. Strains were cultured aerobically at 37˚C in Sabouraud broth. Yeast growth was evaluated by turbidimetry. Biofilm biomass was quantified on a polystyrene support by crystal violet staining and on acrylic surfaces by counts of colony forming units. Lysozyme affected biofilm formation to a greater extent than it affected growth. For the ATCC 10231 reference strain, lysozyme acted as a biofilm promotor on polystyrene at the highest concentration tested (1,000 µg/ml, non‑physiological). When the reference strain was investigated on acrylic resin support, lysozyme acted as a significant biofilm promotor on rough resin, but less on smooth resin. The attached biomass in the presence of physiological concentrations of lysozyme (10‑30 µg/ml) was significantly decreased compared with the hypothetical value of 100% using a one‑sample t‑test, but a comparison between the different lysozyme conditions using analysis of variance and post hoc tests did not reveal significant differences. In 10 wild strains, different patterns of biofilm formation on polystyrene were observed in the presence of lysozyme. Some strains, characterized by large amounts of biofilm formation in the presence of 1,000 µg/ml lysozyme, were poor biofilm producers at low concentrations of lysozyme. In contrast, some strains that were poor biofilm producers with a high lysozyme concentration were more inhibited by low concentrations of lysozyme. The present study emphasizes the need to develop strategies for biofilm control based on in vitro experiments, and to implement these in clinical trials prior to approval of hygiene products enriched with exocrine proteins, such as lysozyme. Further studies will extend these investigations to other Candida species, and to fungi and bacteria present in oral biofilms.}, } @article {pmid28138101, year = {2017}, author = {Richter, LV and Franks, AE and Weis, RM and Sandler, SJ}, title = {Significance of a Posttranslational Modification of the PilA Protein of Geobacter sulfurreducens for Surface Attachment, Biofilm Formation, and Growth on Insoluble Extracellular Electron Acceptors.}, journal = {Journal of bacteriology}, volume = {199}, number = {8}, pages = {}, pmid = {28138101}, issn = {1098-5530}, mesh = {Amino Acid Sequence ; Bacterial Adhesion/*physiology ; Bacteriological Techniques ; Bioelectric Energy Sources/microbiology ; Biofilms/*growth & development ; Culture Media ; Fimbriae Proteins/chemistry/genetics/*metabolism ; Gene Expression Regulation, Bacterial/*physiology ; Geobacter/cytology/genetics/metabolism/*physiology ; Glycerophosphates/chemistry ; Protein Processing, Post-Translational ; }, abstract = {Geobacter sulfurreducens, an anaerobic metal-reducing bacterium, possesses type IV pili. These pili are intrinsic structural elements in biofilm formation and, together with a number of c-type cytochromes, are thought to serve as conductive nanowires enabling long-range electron transfer (ET) to metal oxides and graphite anodes. Here, we report that a posttranslational modification of a nonconserved amino acid residue within the PilA protein, the structural subunit of the type IV pili, is crucial for growth on insoluble extracellular electron acceptors. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of the secreted PilA protein revealed a posttranslational modification of tyrosine-32 with a moiety of a mass consistent with a glycerophosphate group. Mutating this tyrosine into a phenylalanine inhibited cell growth with Fe(III) oxides as the sole electron acceptor. In addition, this amino acid substitution severely diminished biofilm formation on graphite surfaces and impaired current output in microbial fuel cells. These results demonstrate that the capability to attach to insoluble electron acceptors plays a crucial role for the cells' ability to utilize them. The work suggests that glycerophosphate modification of Y32 is a key factor contributing to the surface charge of type IV pili, influencing the adhesion of Geobacter to specific surfaces.IMPORTANCE Type IV pili are bacterial appendages that function in cell adhesion, virulence, twitching motility, and long-range electron transfer (ET) from bacterial cells to insoluble extracellular electron acceptors. The mechanism and role of type IV pili for ET in Geobacter sulfurreducens is still a subject of research. In this study, we identified a posttranslational modification of the major G. sulfurreducens type IV pilin, suggested to be a glycerophosphate moiety. We show that a mutant in which the glycerophosphate-modified tyrosine-32 is replaced with a phenylalanine has reduced abilities for ET and biofilm formation compared with those of the wild type. The results show the importance of the glycerophosphate-modified tyrosine for surface attachment and electron transfer in electrode- or Fe(III)-respiring G. sulfurreducens cells.}, } @article {pmid28135798, year = {2017}, author = {Nguyen, TK and Lam, SJ and Ho, KK and Kumar, N and Qiao, GG and Egan, S and Boyer, C and Wong, EH}, title = {Rational Design of Single-Chain Polymeric Nanoparticles That Kill Planktonic and Biofilm Bacteria.}, journal = {ACS infectious diseases}, volume = {3}, number = {3}, pages = {237-248}, doi = {10.1021/acsinfecdis.6b00203}, pmid = {28135798}, issn = {2373-8227}, mesh = {Animals ; Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Cell Line ; Drug Design ; Drug Resistance, Bacterial ; Gram-Negative Bacteria/*drug effects/physiology ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Nanoparticles/chemistry ; Plankton/*drug effects ; Polymers/*chemistry/pharmacology ; Rats ; Structure-Activity Relationship ; }, abstract = {Infections caused by multidrug-resistant bacteria are on the rise and, therefore, new antimicrobial agents are required to prevent the onset of a postantibiotic era. In this study, we develop new antimicrobial compounds in the form of single-chain polymeric nanoparticles (SCPNs) that exhibit excellent antimicrobial activity against Gram-negative bacteria (e.g., Pseudomonas aeruginosa) at micromolar concentrations (e.g., 1.4 μM) and remarkably kill ≥99.99% of both planktonic cells and biofilm within an hour. Linear random copolymers, which comprise oligoethylene glycol (OEG), hydrophobic, and amine groups, undergo self-folding in aqueous systems due to intramolecular hydrophobic interactions to yield these SCPNs. By systematically varying the hydrophobicity of the polymer, we can tune the extent of cell membrane wall disruption, which in turn governs the antimicrobial activity and rate of resistance acquisition in bacteria. We also show that the incorporation of OEG groups into the polymer design is essential in preventing complexation with proteins in biological medium, thereby maintaining the antimicrobial efficacy of the compound even in in vivo mimicking conditions. In comparison to the last-resort antibiotic colistin, our lead agents have a higher therapeutic index (by ca. 2-3 times) and hence better biocompatibility. We believe that the SCPNs developed here have potential for clinical applications and the information pertaining to their structure-activity relationship will be valuable toward the general design of synthetic antimicrobial (macro)molecules.}, } @article {pmid28134351, year = {2017}, author = {Kim, D and Sengupta, A and Niepa, TH and Lee, BH and Weljie, A and Freitas-Blanco, VS and Murata, RM and Stebe, KJ and Lee, D and Koo, H}, title = {Candida albicans stimulates Streptococcus mutans microcolony development via cross-kingdom biofilm-derived metabolites.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {41332}, pmid = {28134351}, issn = {2045-2322}, support = {R01 DE025220/DE/NIDCR NIH HHS/United States ; S10 RR027128/RR/NCRR NIH HHS/United States ; }, mesh = {*Biofilms/drug effects ; Candida albicans/drug effects/*physiology ; Colony Count, Microbial ; Culture Media, Conditioned/pharmacology ; Farnesol/pharmacology ; Fungi/drug effects ; Glucosyltransferases/metabolism ; *Metabolome ; Microfluidics ; Nanoparticles/chemistry ; Permeability ; Streptococcus mutans/drug effects/*growth & development ; }, abstract = {Candida albicans is frequently detected with heavy infection of Streptococcus mutans in plaque-biofilms from children affected with early-childhood caries, a prevalent and costly oral disease. The presence of C. albicans enhances S. mutans growth within biofilms, yet the chemical interactions associated with bacterial accumulation remain unclear. Thus, this study was conducted to investigate how microbial products from this cross-kingdom association modulate S. mutans build-up in biofilms. Our data revealed that bacterial-fungal derived conditioned medium (BF-CM) significantly increased the growth of S. mutans and altered biofilm 3D-architecture in a dose-dependent manner, resulting in enlarged and densely packed bacterial cell-clusters (microcolonies). Intriguingly, BF-CM induced S. mutans gtfBC expression (responsible for Gtf exoenzymes production), enhancing Gtf activity essential for microcolony development. Using a recently developed nanoculture system, the data demonstrated simultaneous microcolony growth and gtfB activation in situ by BF-CM. Further metabolites/chromatographic analyses of BF-CM revealed elevated amounts of formate and the presence of Candida-derived farnesol, which is commonly known to exhibit antibacterial activity. Unexpectedly, at the levels detected (25-50 μM), farnesol enhanced S. mutans-biofilm cell growth, microcolony development, and Gtf activity akin to BF-CM bioactivity. Altogether, the data provide new insights on how extracellular microbial products from cross-kingdom interactions stimulate the accumulation of a bacterial pathogen within biofilms.}, } @article {pmid28134244, year = {2017}, author = {Donato, V and Ayala, FR and Cogliati, S and Bauman, C and Costa, JG and Leñini, C and Grau, R}, title = {Bacillus subtilis biofilm extends Caenorhabditis elegans longevity through downregulation of the insulin-like signalling pathway.}, journal = {Nature communications}, volume = {8}, number = {}, pages = {14332}, pmid = {28134244}, issn = {2041-1723}, mesh = {Animals ; Bacillus subtilis/*physiology ; Biofilms ; Caenorhabditis elegans/*physiology ; Caenorhabditis elegans Proteins/*metabolism ; Down-Regulation ; Feeding Behavior/physiology ; Forkhead Transcription Factors/metabolism ; Insulin/metabolism ; Longevity/*physiology ; Nitric Oxide/metabolism ; Predatory Behavior/physiology ; Receptor, Insulin/metabolism ; Signal Transduction/*physiology ; Transcription Factors/metabolism ; }, abstract = {Beneficial bacteria have been shown to affect host longevity, but the molecular mechanisms mediating such effects remain largely unclear. Here we show that formation of Bacillus subtilis biofilms increases Caenorhabditis elegans lifespan. Biofilm-proficient B. subtilis colonizes the C. elegans gut and extends worm lifespan more than biofilm-deficient isogenic strains. Two molecules produced by B. subtilis - the quorum-sensing pentapeptide CSF and nitric oxide (NO) - are sufficient to extend C. elegans longevity. When B. subtilis is cultured under biofilm-supporting conditions, the synthesis of NO and CSF is increased in comparison with their production under planktonic growth conditions. We further show that the prolongevity effect of B. subtilis biofilms depends on the DAF-2/DAF-16/HSF-1 signalling axis and the downregulation of the insulin-like signalling (ILS) pathway.}, } @article {pmid28133715, year = {2017}, author = {Mei, L and Chieng, J and Wong, C and Benic, G and Farella, M}, title = {Factors affecting dental biofilm in patients wearing fixed orthodontic appliances.}, journal = {Progress in orthodontics}, volume = {18}, number = {1}, pages = {4}, pmid = {28133715}, issn = {2196-1042}, mesh = {Adolescent ; Age Factors ; Biofilms/*growth & development ; Cuspid/microbiology ; Dental Plaque Index ; Female ; Gingiva/microbiology ; Humans ; Incisor/microbiology ; Male ; Motivation ; Orthodontic Appliances/adverse effects/*microbiology ; Risk Factors ; Sex Factors ; Toothbrushing ; }, abstract = {BACKGROUND: The aim of this study is to investigate the amount and the distribution of biofilm in patients wearing fixed appliances and its relation with age, gender, frequency of tooth brushing, and patient motivation.

METHODS: The sample comprised 52 patients (15.5 ± 3.6 years old, 30 females and 22 males) wearing fixed orthodontic appliances. Dental biofilm was assessed using a modified plaque index (PI). A questionnaire was used to collect patient's information, including gender, age, treatment motivation, and frequency of tooth brushing.

RESULTS: Gingival (PI score = 0.9 ± 0.7), mesial (0.8 ± 0.6), and distal (0.8 ± 0.5) areas accumulated more biofilm than occlusal areas (0.3 ± 0.3) (P < 0.038). The maxillary lateral incisors (1.1 ± 0.8) and maxillary canines (1.0 ± 0.8) had more biofilm than other teeth (P < 0.05). The maxillary arch (0.8 ± 0.7) had significantly more biofilm than mandibular arch (0.6 ± 0.6) (P = 0.042). No significant difference was found between the right side (0.7 ± 0.7) and left side (0.7 ± 0.6) (P = 0.627). Less biofilm was found in females (0.6 ± 0.5), adults (0.3 ± 0.3), and "self-motivated" patients (0.3 ± 0.3), compared with males (0.9 ± 0.5), children (0.8 ± 0.6), and "family-motivated" patients (1.1 ± 0.5) (P < 0.001). The amount of biofilm was associated with self-report of the frequency of daily tooth brushing (P < 0.001).

CONCLUSIONS: Patients wearing fixed orthodontic appliances have the highest biofilm accumulation on the maxillary lateral incisors and maxillary canines, particularly in the gingival area and areas behind arch wires. Less biofilm was observed in female and adult patients and in those who were self-motivated and brushed their teeth more often.}, } @article {pmid28133457, year = {2016}, author = {Magalhães, AP and Lopes, SP and Pereira, MO}, title = {Insights into Cystic Fibrosis Polymicrobial Consortia: The Role of Species Interactions in Biofilm Development, Phenotype, and Response to In-Use Antibiotics.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {2146}, pmid = {28133457}, issn = {1664-302X}, abstract = {Cystic Fibrosis (CF) airways disease involves complex polymicrobial infections where different bacterial species can interact and influence each other and/or even interfere with the whole community. To gain insights into the role that interactions between Pseudomonas aeruginosa in co-culture with Staphylococcus aureus, Inquilinus limosus, and Stenotrophomonas maltophilia may play in infection, the reciprocal effect during biofilm formation and the response of dual biofilms toward ciprofloxacin under in vitro atmospheres with different oxygen availabilities were evaluated. Biofilm formation kinetics showed that the growth of S. aureus, I. limosus, and S. maltophilia was disturbed in the presence of P. aeruginosa, under both aerobic and anaerobic environments. On the other hand, under aerobic conditions, I. limosus led to a decrease in biofilm mass production by P. aeruginosa, although biofilm-cells viability remains unaltered. The interaction between S. maltophilia and P. aeruginosa positively influenced dual biofilm development by increasing its biomass. Compared with monocultures, biomass of P. aeruginosa+ S. aureus biofilms was significantly reduced by reciprocal interference. When grown in dual biofilms with P. aeruginosa, ciprofloxacin was less effective against S. aureus, I. limosus, and S. maltophilia, with increasing antibiotic doses leading to drastic inhibitions of P. aeruginosa cultivability. Therefore, P. aeruginosa might be responsible for the protection of the whole dual consortia against ciprofloxacin activity. Based on the overall data, it can be speculated that reciprocal interferences occur between the different bacterial species in CF lung, regardless the level of oxygen. The findings also suggest that alterations of bacterial behavior due to species interplay may be important for disease progression in CF infection.}, } @article {pmid28131960, year = {2017}, author = {Matos, AO and Ricomini-Filho, AP and Beline, T and Ogawa, ES and Costa-Oliveira, BE and de Almeida, AB and Nociti Junior, FH and Rangel, EC and da Cruz, NC and Sukotjo, C and Mathew, MT and Barão, VAR}, title = {Three-species biofilm model onto plasma-treated titanium implant surface.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {152}, number = {}, pages = {354-366}, doi = {10.1016/j.colsurfb.2017.01.035}, pmid = {28131960}, issn = {1873-4367}, mesh = {Actinomyces/growth & development ; Animals ; Bacterial Adhesion ; *Biocompatible Materials ; Biofilms/*growth & development ; Cell Line ; Dental Implants/microbiology ; Fusobacterium nucleatum/growth & development ; Mice ; Microscopy, Atomic Force ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Oxidation-Reduction ; Streptococcus sanguis/growth & development ; Surface Properties ; Titanium/*chemistry ; }, abstract = {In this study, titanium (Ti) was modified with biofunctional and novel surface by micro-arc oxidation (MAO) and glow discharge plasma (GDP) and we tested the development of a three-species periodontopatogenic biofilm onto the treated commercially-pure titanium (cpTi) surfaces. Machined and sandblasted surfaces were used as control group. Several techniques for surface characterizations and monoculture on bone tissue cells were performed. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum was developed onto cpTi discs for 16.5h (early biofilm) and 64.5h (mature biofilm). The number of viable microorganisms and the composition of the extracellular matrix (proteins and carbohydrates) were determined. The biofilm organization was analyzed by scanning electron microscopy (SEM) and Confocal laser scanning microscopy (CLSM). In addition, MC3T3-E1 cells were cultured on the Ti surfaces and cell proliferation (MTT) and morphology (SEM) were assessed. MAO treatment produced oxide films rich in calcium and phosphorus with a volcano appearance while GDP treatment produced silicon-based smooth thin-film. Plasma treatments were able to increase the wettability of cpTi (p<0.05). An increase of surface roughness (p<0.05) and formation of anatase and rutile structures was noted after MAO treatment. GDP had the greatest surface free energy (p<0.05) while maintaining the surface roughness compared to the machined control (p>0.05). Plasma treatment did not affect the viable microorganisms counts, but the counts of F. nucleatum was lower for MAO treatment at early biofilm phase. Biofilm extracellular matrix was similar among the groups, excepted for GDP that presented the lowest protein content. Moreover, cell proliferation was not significantly affected by the experimental, except for MAO at 6days that resulted in an increased cell proliferative. Together, these findings indicate that plasma treatments are a viable and promising technology to treat bone-integrated dental implants as the new surfaces displayed improved mechanical and biological properties with no increase in biofilm proliferation.}, } @article {pmid28131956, year = {2017}, author = {Felipe, V and Morgante, CA and Somale, PS and Varroni, F and Zingaretti, ML and Bachetti, RA and Correa, SG and Porporatto, C}, title = {Evaluation of the biofilm forming ability and its associated genes in Staphylococcus species isolates from bovine mastitis in Argentinean dairy farms.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {278-286}, doi = {10.1016/j.micpath.2017.01.047}, pmid = {28131956}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/genetics ; Animals ; Argentina ; Biofilms/*growth & development ; Cattle ; Farms ; *Genes, Bacterial ; Mastitis, Bovine/*microbiology ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/*genetics/isolation & purification/*physiology ; }, abstract = {Staphylococcus aureus and coagulase-negative staphylococci (CNS) are important causes of intramammary infection in dairy cattle, and their ability to produce biofilm is considered an important virulence property in the pathogenesis of mastitis. However, the published date on mechanisms and factors involved in infection persistence in the mammary gland remains unclear. The aim of this study was to investigate whether the main Staphylococcus species involved in bovine intramammary infections possess specific characteristics that promote colonization of the udder. We evaluated the biofilm-forming ability and distribution of adhesion- and biofilm-associated genes of Staphylococcus spp. isolated from bovine mastitis infected animals in Argentinean dairy farms. For this purpose, the phenotypic biofilm formation ability of 209 Staphylococcus spp. from bovine mastitis was investigated. All isolates produced biofilm in vitro, being 35,0% and 45,0% of the 127 S. aureus or 51,0% and 29,0% of the 82 CNS strong and moderate biofilm producers respectively. All S. aureus samples were PCR-positive for icaA, icaD, clfA, clfB and fnbpA genes, 76.3% were positive for fnbpB gene and 11.0% were positive for bap gene. In CNS isolates, the positive rates for icaA and icaD were 73.2%, while for clfA, clfB, fnbpA fnbpB and bap genes the percentage were lower. The results demonstrate that in Staphylococcus spp. biofilm formation, the polysaccharide and the adhesion- and biofilm-associated genes are of overall importance on bovine mastitis in Argentina. Therefore, future works should focus on these pathogenic specific factors for the development of more effective therapies of control, being essential to consider the ability of isolates to produce biofilm.}, } @article {pmid28131895, year = {2017}, author = {McLaughlin, K and Folorunso, AO and Deeni, YY and Foster, D and Gorbatiuk, O and Hapca, SM and Immoor, C and Koza, A and Mohammed, IU and Moshynets, O and Rogalsky, S and Zawadzki, K and Spiers, AJ}, title = {Biofilm formation and cellulose expression by Bordetella avium 197N, the causative agent of bordetellosis in birds and an opportunistic respiratory pathogen in humans.}, journal = {Research in microbiology}, volume = {168}, number = {5}, pages = {419-430}, doi = {10.1016/j.resmic.2017.01.002}, pmid = {28131895}, issn = {1769-7123}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Bird Diseases/microbiology ; Birds/microbiology ; Bordetella Infections/*microbiology/veterinary ; Bordetella avium/*genetics/pathogenicity/*physiology ; Cellulose/*biosynthesis ; Cyclic GMP/analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Glucosyltransferases/genetics/metabolism ; Humans ; Operon ; Opportunistic Infections/microbiology ; Pseudomonas fluorescens/genetics ; Respiratory Tract Infections/microbiology ; }, abstract = {Although bacterial cellulose synthase (bcs) operons are widespread within the Proteobacteria phylum, subunits required for the partial-acetylation of the polymer appear to be restricted to a few γ-group soil, plant-associated and phytopathogenic pseudomonads, including Pseudomonas fluorescens SBW25 and several Pseudomonas syringae pathovars. However, a bcs operon with acetylation subunits has also been annotated in the unrelated β-group respiratory pathogen, Bordetella avium 197N. Our comparison of subunit protein sequences and GC content analyses confirms the close similarity between the B. avium 197N and pseudomonad operons and suggests that, in both cases, the cellulose synthase and acetylation subunits were acquired as a single unit. Using static liquid microcosms, we can confirm that B. avium 197N expresses low levels of cellulose in air-liquid interface biofilms and that biofilm strength and attachment levels could be increased by elevating c-di-GMP levels like the pseudomonads, but cellulose was not required for biofilm formation itself. The finding that B. avium 197N is capable of producing cellulose from a highly-conserved, but relatively uncommon bcs operon raises the question of what functional role this modified polymer plays during the infection of the upper respiratory tract or survival between hosts, and what environmental signals control its production.}, } @article {pmid28131567, year = {2017}, author = {Liu, DZ and Jindal, S and Amamcharla, J and Anand, S and Metzger, L}, title = {Short communication: Evaluation of a sol-gel-based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk.}, journal = {Journal of dairy science}, volume = {100}, number = {4}, pages = {2577-2581}, doi = {10.3168/jds.2016-12141}, pmid = {28131567}, issn = {1525-3198}, mesh = {Animals ; Bacterial Adhesion ; Biofilms ; Milk ; *Pasteurization ; Stainless Steel/*chemistry ; }, abstract = {Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm[2] and 0.37 mg/cm[2] on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface.}, } @article {pmid28129375, year = {2017}, author = {Gogoi-Tiwari, J and Williams, V and Waryah, CB and Costantino, P and Al-Salami, H and Mathavan, S and Wells, K and Tiwari, HK and Hegde, N and Isloor, S and Al-Sallami, H and Mukkur, T}, title = {Mammary Gland Pathology Subsequent to Acute Infection with Strong versus Weak Biofilm Forming Staphylococcus aureus Bovine Mastitis Isolates: A Pilot Study Using Non-Invasive Mouse Mastitis Model.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0170668}, pmid = {28129375}, issn = {1932-6203}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Disease Models, Animal ; Female ; Interleukin-1beta/metabolism ; Mammary Glands, Animal/metabolism/microbiology/pathology ; Mastitis, Bovine/metabolism/*microbiology/pathology ; Mice ; Pilot Projects ; Staphylococcal Infections/*microbiology/pathology ; Staphylococcus aureus/*growth & development/metabolism/pathogenicity ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {BACKGROUND: Biofilm formation by Staphylococcus aureus is an important virulence attribute because of its potential to induce persistent antibiotic resistance, retard phagocytosis and either attenuate or promote inflammation, depending upon the disease syndrome, in vivo. This study was undertaken to evaluate the potential significance of strength of biofilm formation by clinical bovine mastitis-associated S. aureus in mammary tissue damage by using a mouse mastitis model.

METHODS: Two S. aureus strains of the same capsular phenotype with different biofilm forming strengths were used to non-invasively infect mammary glands of lactating mice. Biofilm forming potential of these strains were determined by tissue culture plate method, ica typing and virulence gene profile per detection by PCR. Delivery of the infectious dose of S. aureus was directly through the teat lactiferous duct without invasive scraping of the teat surface. Both bacteriological and histological methods were used for analysis of mammary gland pathology of mice post-infection.

RESULTS: Histopathological analysis of the infected mammary glands revealed that mice inoculated with the strong biofilm forming S. aureus strain produced marked acute mastitic lesions, showing profuse infiltration predominantly with neutrophils, with evidence of necrosis in the affected mammary glands. In contrast, the damage was significantly less severe in mammary glands of mice infected with the weak biofilm-forming S. aureus strain. Although both IL-1β and TNF-α inflammatory biomarkers were produced in infected mice, level of TNF-α produced was significantly higher (p<0.05) in mice inoculated with strong biofilm forming S. aureus than the weak biofilm forming strain.

CONCLUSION: This finding suggests an important role of TNF-α in mammary gland pathology post-infection with strong biofilm-forming S. aureus in the acute mouse mastitis model, and offers an opportunity for the development of novel strategies for reduction of mammary tissue damage, with or without use of antimicrobials and/or anti-inflammatory compounds for the treatment of bovine mastitis.}, } @article {pmid28128637, year = {2017}, author = {Xu, Y and Shi, C and Wu, Q and Zheng, Z and Liu, P and Li, G and Peng, X and Xia, X}, title = {Antimicrobial Activity of Punicalagin Against Staphylococcus aureus and Its Effect on Biofilm Formation.}, journal = {Foodborne pathogens and disease}, volume = {14}, number = {5}, pages = {282-287}, doi = {10.1089/fpd.2016.2226}, pmid = {28128637}, issn = {1556-7125}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Hydrolyzable Tannins/*pharmacology ; Lythraceae/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {Punicalagin, one of the main active compounds in pomegranate peel, has been reported to possess many properties, including antioxidant, antimicrobial, antiviral, and immunosuppressive activities. The aim of this study was to investigate the antibacterial effect of punicalagin against Staphylococcus aureus and possible mode of action. Growth inhibition activity was examined by the agar diffusion method. Then agar dilution method was adopted to determine the minimum inhibitory concentration (MIC). The effects of punicalagin on cell membrane were assessed by measuring potassium efflux. Morphological changes of S. aureus were assessed by scanning and transmission electron microscopy. Crystal violet assay was applied to investigate antibiofilm activity of punicalagin. Punicalagin exhibited good antistaphylococcal effect with an MIC of 0.25 mg/mL. An increase of potassium efflux was observed when cells were treated with punicalagin at 2 × MIC. Punicalagin induced morphological damages to the cell membrane. Moreover, punicalagin exerted a remarkable inhibitory effect on biofilm formation of S. aureus. These findings suggest that punicalagin has antimicrobial and antibiofilm activities against S. aureus and may have potential application to control S. aureus contamination in food industry.}, } @article {pmid28128094, year = {2016}, author = {Domínguez-Herrera, J and López-Rojas, R and Smani, Y and Labrador-Herrera, G and Pachón, J}, title = {Efficacy of ceftaroline versus vancomycin in an experimental foreign-body and systemic infection model caused by biofilm-producing methicillin-resistant Staphylococcus epidermidis.}, journal = {International journal of antimicrobial agents}, volume = {48}, number = {6}, pages = {661-665}, doi = {10.1016/j.ijantimicag.2016.09.011}, pmid = {28128094}, issn = {1872-7913}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Bacterial Load ; Biofilms/drug effects ; Cephalosporins/*therapeutic use ; Disease Models, Animal ; Female ; Foreign Bodies/complications ; Methicillin Resistance ; Mice, Inbred C57BL ; Microbial Sensitivity Tests ; Random Allocation ; Sepsis/*drug therapy/microbiology ; Soft Tissue Infections/*drug therapy/microbiology ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus epidermidis/*drug effects/isolation & purification ; Treatment Outcome ; Vancomycin/*therapeutic use ; }, abstract = {In this study, the efficacy of ceftaroline versus vancomycin against biofilm-producing methicillin-resistant Staphylococcus epidermidis (MRSE) in a murine model of foreign-body and systemic infection was compared. Two bacteraemic biofilm-producing MRSE strains were used (SE284 and SE385). The minimum inhibitory concentrations (MICs) for strains SE284 and SE385, were, respectively, 0.25 mg/L and 0.5 mg/L for ceftaroline and 4 mg/L and 2 mg/L for vancomycin. The in vitro bactericidal activities of ceftaroline and vancomycin were evaluated using time-kill curves. A foreign-body and systemic infection model in neutropenic female C57BL/6 mice was used to ascertain in vivo efficacy. Animals were randomly allocated into three groups (n = 15) without treatment (controls) or treated with ceftaroline 50 mg/kg every 8 h or vancomycin 110 mg/kg every 6 h. In vitro, ceftaroline showed concentration-dependent bactericidal activity, whilst vancomycin presented time-dependent activity. In the experimental in vivo model, ceftaroline and vancomycin decreased the liver and catheter bacterial concentrations (P <0.05) and increased survival (P <0.05) for both strains. In conclusion, ceftaroline is as effective as vancomycin in the treatment of experimental foreign-body and systemic infection caused by biofilm-producing MRSE.}, } @article {pmid28127162, year = {2016}, author = {Syed, M and Chopra, R and Shrivastava, V and Sachdev, V}, title = {Comparative evaluation of 0.2% Chlorhexidine Mouthwash, Xylitol Chewing Gum, and Combination of 0.2% Chlorhexidine Mouthwash and Xylitol Chewing Gum on Salivary Streptococcus mutans and Biofilm Levels in 8- to 12-Year-Old Children.}, journal = {International journal of clinical pediatric dentistry}, volume = {9}, number = {4}, pages = {313-319}, pmid = {28127162}, issn = {0974-7052}, abstract = {AIM: To assess the effect of combining 0.2% chlorhexidine (CHX) mouthwash with xylitol (XYL) chewing gum on Streptococcus mutans and biofilm levels among 8- to 12-year-old children.

MATERIALS AND METHODS: Sixty children aged 8 to 12 years were selected with moderate and high salivary S. mutans levels. They were divided into three groups of 20 children each: (1) XYL group where the subjects chewed XYL twice daily; (2) CHX where rinsing was done twice daily; and (3) combination of XYL and CHX group (XYL+CHX) where both the agents were used once daily. The S. mutans colony-forming units (CFUs) were counted by using the mitis salivarius agar plate at the beginning of the study and at 15 days, 1, 2, and 6 months from the start of the study.

RESULTS: The XYL+CHX group showed the maximum reduction in both the biofilm and S. mutans scores throughout the study period.

CONCLUSION: The XYL+CHX combination reduced both the biofilm and S. mutans score significantly better than either XYL chewing gums or CHX mouthwash used alone.

HOW TO CITE THIS ARTICLE: Syed M, Chopra R, Shrivastava V, Sachdev V. Comparative evaluation of 0.2% Chlorhexidine Mouthwash, Xylitol Chewing Gum, and Combination of 0.2% Chlorhexidine Mouthwash and Xylitol Chewing Gum on Salivary Streptococcus mutans and Biofilm Levels in 8- to 12-Year-Old Children. Int J Clin Pediatr Dent 2016;9(4):313-319.}, } @article {pmid28126929, year = {2017}, author = {Cimdins, A and Lüthje, P and Li, F and Ahmad, I and Brauner, A and Römling, U}, title = {Draft Genome Sequences of Semiconstitutive Red, Dry, and Rough Biofilm-Forming Commensal and Uropathogenic Escherichia coli Isolates.}, journal = {Genome announcements}, volume = {5}, number = {4}, pages = {}, pmid = {28126929}, issn = {2169-8287}, abstract = {Strains of Escherichia coli exhibit diverse biofilm formation capabilities. E. coli K-12 expresses the red, dry, and rough (rdar) morphotype below 30°C, whereas clinical isolates frequently display the rdar morphotype semiconstitutively. We sequenced the genomes of eight E. coli strains to subsequently investigate the molecular basis of semiconstitutive rdar morphotype expression.}, } @article {pmid28125700, year = {2017}, author = {Eick, S and Meier, I and Spoerlé, F and Bender, P and Aoki, A and Izumi, Y and Salvi, GE and Sculean, A}, title = {In Vitro-Activity of Er:YAG Laser in Comparison with other Treatment Modalities on Biofilm Ablation from Implant and Tooth Surfaces.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0171086}, pmid = {28125700}, issn = {1932-6203}, mesh = {Animals ; *Biofilms ; Decontamination/*methods ; Dental Implants/*microbiology ; Dentin ; *Lasers, Solid-State ; Periodontal Diseases/*therapy ; Surface Properties ; Swine ; Titanium ; Tooth/*microbiology ; }, abstract = {BACKGROUND AND AIM: Bacterial biofilms play a major role in the etiology of periodontal and peri-implant diseases. The aim of the study was to evaluate the removal of bacterial biofilms and attachment of epithelial cells (EC), gingival fibroblasts (GF) and osteoblast-like cells (OC) to dentin and titanium surfaces after Er:YAG laser (Er:YAG) in comparison with other treatment methods.

MATERIAL AND METHODS: Multi-species bacterial biofilms were grown on standardized dentin and titanium specimens with a sand-blasted and acid etched (SLA) surface for 3.5 d. Thereafter, the specimens were placed into artificially-created pockets. The following methods for biofilm removal were used: 1) Gracey (dentin) or titanium curettes (CUR), 2) Er:YAG, 3) photodynamic therapy (PDT) and 4) CUR with adjunctive PDT (CUR/PDT). Colony forming units (CFUs) of the remaining biofilms and attachment of EC, GF and OC were determined. Statistical analysis was performed by means of ANOVA with post-hoc LSD.

RESULTS: All treatment methods decreased statistically significantly (p<0.001) total CFUs in biofilms compared with untreated dentin and titanium surfaces respectively. On dentin, Er:YAG was equally efficient as CUR and PDT but inferior to CUR/PDT (p = 0.005). On titanium, surfaces, the use of Er:YAG resulted in statistically significantly superior biofilm removal compared to the 3 other treatments (each p<0.001). Counts of attached EC, GF and OC were the lowest on untreated contaminated dentin and titanium surfaces each. After CUR/PDT higher EC counts were found on dentin (p = 0.006). On titanium, all decontamination methods statistically significantly increased (p<0.001) the counts of attached EC without differences between groups. Statistically significantly higher counts of GF (p = 0.024) and OC (p<0.001) were observed after Er:YAG decontamination compared with untreated surfaces.

CONCLUSION: Ablation of subgingival biofilms and in particular decontamination of titanium implant surfaces with an Er:YAG laser seem to be a promising approach and warrants further investigations.}, } @article {pmid28124269, year = {2017}, author = {Minière, M and Boutin, O and Soric, A}, title = {Experimental coupling and modelling of wet air oxidation and packed-bed biofilm reactor as an enhanced phenol removal technology.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {8}, pages = {7693-7704}, pmid = {28124269}, issn = {1614-7499}, mesh = {Acetic Acid/metabolism ; Air ; Biofilms ; *Bioreactors ; Catalysis ; Kinetics ; Oxidation-Reduction ; Phenol/*metabolism ; Waste Disposal, Fluid/methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Experimental coupling of wet air oxidation process and aerobic packed-bed biofilm reactor is presented. It has been tested on phenol as a model refractory compound. At 30 MPa and 250 °C, wet air oxidation batch experiments led to a phenol degradation of 97% and a total organic carbon removal of 84%. This total organic carbon was mainly due to acetic acid. To study the interest of coupling processes, wet air oxidation effluent was treated in a biological treatment process. This step was made up of two packed-bed biofilm reactors in series: the first one acclimated to phenol and the second one to acetic acid. After biological treatment, phenol and total organic carbon removal was 99 and 97% respectively. Thanks to parameters from literature, previous studies (kinetic and thermodynamic) and experimental data from this work (hydrodynamic parameters and biomass characteristics), both treatment steps were modelled. This modelling allows the simulation of the coupling process. Experimental results were finally well reproduced by the continuous coupled process model: relative error on phenol removal efficiency was 1 and 5.5% for wet air oxidation process and packed-bed biofilm reactor respectively.}, } @article {pmid28124027, year = {2017}, author = {Marti, S and Puig, C and Merlos, A and Viñas, M and de Jonge, MI and Liñares, J and Ardanuy, C and Langereis, JD}, title = {Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae.}, journal = {mSphere}, volume = {2}, number = {1}, pages = {}, pmid = {28124027}, issn = {2379-5042}, abstract = {Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that mainly causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. However, the underlying mechanisms involved in this process are poorly elucidated. In this study, we used a transposon mutant library to identify bacterial genes involved in biofilm formation. The growth and biofilm formation of 4,172 transposon mutants were determined, and the involvement of the identified genes in biofilm formation was validated in in vitro experiments. Here, we present experimental data showing that increased bacterial lysis, through interference with peptidoglycan synthesis, results in elevated levels of extracellular DNA, which increased biofilm formation. Interestingly, similar results were obtained with subinhibitory concentrations of β-lactam antibiotics, known to interfere with peptidoglycan synthesis, but such an effect does not appear with other classes of antibiotics. These results indicate that treatment with β-lactam antibiotics, especially for β-lactam-resistant NTHi isolates, might increase resistance to antibiotics by increasing biofilm formation. IMPORTANCE Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds.}, } @article {pmid28122010, year = {2017}, author = {Marsden, AE and Grudzinski, K and Ondrey, JM and DeLoney-Marino, CR and Visick, KL}, title = {Impact of Salt and Nutrient Content on Biofilm Formation by Vibrio fischeri.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0169521}, pmid = {28122010}, issn = {1932-6203}, support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM114288/GM/NIGMS NIH HHS/United States ; }, mesh = {Agar ; Aliivibrio fischeri/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Culture Media ; Sodium Chloride/*pharmacology ; }, abstract = {Vibrio fischeri, a marine bacterium and symbiont of the Hawaiian bobtail squid Euprymna scolopes, depends on biofilm formation for successful colonization of the squid's symbiotic light organ. Here, we investigated if culture conditions, such as nutrient and salt availability, affect biofilm formation by V. fischeri by testing the formation of wrinkled colonies on solid media. We found that V. fischeri forms colonies with more substantial wrinkling when grown on the nutrient-dense LBS medium containing NaCl relative to those formed on the more nutrient-poor, seawater-salt containing SWT medium. The presence of both tryptone and yeast extract was necessary for the production of "normal" wrinkled colonies; when grown on tryptone alone, the colonies displayed a divoting phenotype and were attached to the agar surface. We also found that the type and concentration of specific seawater salts influenced the timing of biofilm formation. Of the conditions assayed, wrinkled colony formation occurred earliest in LBS(-Tris) media containing 425 mM NaCl, 35 mM MgSO4, and 5 mM CaCl2. Pellicle formation, another measure of biofilm development, was also enhanced in these growth conditions. Therefore, both nutrient and salt availability contribute to V. fischeri biofilm formation. While growth was unaffected, these optimized conditions resulted in increased syp locus expression as measured by a PsypA-lacZ transcriptional reporter. We anticipate these studies will help us understand how the natural environment of V. fischeri affects its ability to form biofilms and, ultimately, colonize E. scolopes.}, } @article {pmid28121033, year = {2017}, author = {Percival, SL}, title = {Importance of biofilm formation in surgical infection.}, journal = {The British journal of surgery}, volume = {104}, number = {2}, pages = {e85-e94}, doi = {10.1002/bjs.10433}, pmid = {28121033}, issn = {1365-2168}, mesh = {Anti-Bacterial Agents/therapeutic use ; Antibiotic Prophylaxis ; Bacterial Adhesion ; Bandages ; *Biofilms/growth & development ; Debridement ; Humans ; Infection Control ; Surgical Wound Infection/diagnosis/*microbiology/*therapy ; Wound Healing ; }, abstract = {BACKGROUND: Biofilms are ubiquitous, and have been observed in both acute and chronic wounds. Their role in wound healing and infection, however, remains controversial. The aim of this review was to provide an overview of the role and relevance of biofilms to surgical wounds.

METHODS: A search of PubMed, Science Direct and Web of Science databases was performed to identify studies related to biofilms. Specifically, studies were sought in acute and chronic wounds, and the management and treatment of non-healing and infected skin and wounds.

RESULTS: Biofilms may develop in all open wounds. In chronic wounds, biofilms may play a role in prolonging and preventing healing, causing chronic inflammation and increasing the risk of infection. Controversies exist regarding the methods presently employed for biofilm detection and management and few data exist to underpin these decisions.

CONCLUSION: Biofilms in acute surgical and chronic wounds appear to cause a delay in healing and potentially increase the risk of infection. Biofilms can be prevented and once developed can be controlled using wound desloughing and debridement.}, } @article {pmid28119141, year = {2017}, author = {Misba, L and Zaidi, S and Khan, AU}, title = {A comparison of antibacterial and antibiofilm efficacy of phenothiazinium dyes between Gram positive and Gram negative bacterial biofilm.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {18}, number = {}, pages = {24-33}, doi = {10.1016/j.pdpdt.2017.01.177}, pmid = {28119141}, issn = {1873-1597}, mesh = {Biofilms/*drug effects/*growth & development/radiation effects ; Coloring Agents/administration & dosage ; Disinfection/*methods ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Enterococcus faecalis/*drug effects/growth & development/radiation effects ; Klebsiella/*drug effects/growth & development/radiation effects ; Phenothiazines/*administration & dosage ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage ; Treatment Outcome ; }, abstract = {BACKGROUND: Antimicrobial photodynamic therapy (APDT) is a process that generates reactive oxygen species (ROS) in presence of photosensitizer, visible light and oxygen which destroys the bacterial cells. We investigated the photoinactivation efficiency of phenothiazinium dyes and the effect of ROS generation on Gram positive and Gram negative bacterial cell as well as on biofilm.

MATERIAL AND METHODS: Enterococcus faecalis and Klebsiella pneumonia were incubated with all the three phenothiazinium dyes and exposed to 630nm of light. After PDT, colony forming unit (CFU) were performed to estimate the cell survival fraction. Intracellular reactive oxygen species (ROS) was detected by DCFH-DA. Crystal violet (CV) assay and extracellular polysaccharides (EPS) reduction assay were performed to analyze antibiofilm effect. Confocal laser electron microscope (CLSM) scanning electron microscope (SEM) was performed to assess the disruption of biofilm.

RESULTS: 8log10 reduction in bacterial count was observed in Enterococcus faecalis while 3log10 in Klebsiella pneumoniae. CV and EPS reduction assay revealed that photodynamic inhibition was more pronounced in Enterococcus faecalis. In addition to this CLSM and SEM study showed an increase in cell permeability of propidium iodide and leakage of cellular constituents in treated preformed biofilm which reflects the antibiofilm action of photodynamic therapy.

CONCLUSION: We conclude that Gram-positive bacteria (Enterococcus faecalis) are more susceptible to APDT due to increased level of ROS generation inside the cell, higher photosensitizer binding efficiency and DNA degradation. Phenothiazinium dyes are proved to be highly efficient against both planktonic and biofilm state of cells.}, } @article {pmid28118640, year = {2017}, author = {Schwendicke, F and Korte, F and Dörfer, CE and Kneist, S and Fawzy El-Sayed, K and Paris, S}, title = {Inhibition of Streptococcus mutans Growth and Biofilm Formation by Probiotics in vitro.}, journal = {Caries research}, volume = {51}, number = {2}, pages = {87-95}, doi = {10.1159/000452960}, pmid = {28118640}, issn = {1421-976X}, mesh = {Animals ; Biofilms/*growth & development ; Cattle ; Dental Caries/*microbiology/*prevention & control ; Probiotics/*therapeutic use ; Streptococcus mutans/*physiology ; }, abstract = {To exert anticaries effects, probiotics are described to inhibit growth and biofilm formation of cariogenic bacteria such as Streptococcus mutans (SM). We screened 8 probiotics and assessed how SM growth or biofilm formation inhibition affects cariogenicity of probiotic-SM mixed-species biofilms in vitro. Growth inhibition was assessed by cocultivating probiotics and 2 SM strains (ATCC 20532/25175) on agar. Probiotics were either precultured before SM cultivation (exclusion), or SM precultured prior to probiotic cultivation (displacement). Inhibition of SM culture growth was assessed visually. Inhibition of SM biofilm formation on bovine enamel was assessed using a continuous-flow short-term biofilm model, again in exclusion or displacement mode. The cariogenicity of mixed-species biofilms of SM with the most promising growth and biofilm formation inhibiting probiotic strains was assessed using an artificial mouth model, and enamel mineral loss (ΔZ) was measured microradiographically. We found limited differences in SM growth inhibition in exclusion versus displacement mode, and in inhibition of SM 20532 versus 25175. Results were therefore pooled. Lactobacillus acidophilus LA-5 inhibited significantly more SM culture growth than most other probiotics. L. casei LC-11 inhibited SM biofilm formation similarly to other alternatives but showed the highest retention of probiotics in the biofilms (p < 0.05). Mineral loss from SM monospecies biofilms (ΔZ = 9,772, 25th/75th percentiles: 6,277/13,558 vol% × µm) was significantly lower than from mixed-species SM × LA-5 biofilms (ΔZ = 24,578, 25th/75th percentiles: 19,081/28,768 vol% × µm; p < 0.01) but significantly higher than from SM × LC-11 biofilms (ΔZ = 4,835, 25th/75th percentiles: 263/7,865 vol% × µm; p < 0.05). Probiotics inhibiting SM culture growth do not necessarily reduce the cariogenicity of SM-probiotic biofilms. Nevertheless, SM biofilm formation inhibition may be relevant in the reduction of cariogenicity.}, } @article {pmid28118386, year = {2017}, author = {Philips, J and Rabaey, K and Lovley, DR and Vargas, M}, title = {Biofilm Formation by Clostridium ljungdahlii Is Induced by Sodium Chloride Stress: Experimental Evaluation and Transcriptome Analysis.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0170406}, pmid = {28118386}, issn = {1932-6203}, mesh = {Biofilms/*drug effects/growth & development ; Biomass ; Carbon ; Clostridium/*drug effects/genetics/physiology/ultrastructure ; Culture Media ; Culture Techniques/instrumentation ; Fimbriae, Bacterial ; Flagella ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Glass ; Graphite ; Osmotic Pressure ; RNA, Bacterial/genetics ; RNA, Ribosomal/genetics ; Sodium Chloride/*pharmacology ; Spores, Bacterial ; Stress, Physiological ; }, abstract = {The acetogen Clostridium ljungdahlii is capable of syngas fermentation and microbial electrosynthesis. Biofilm formation could benefit both these applications, but was not yet reported for C. ljungdahlii. Biofilm formation does not occur under standard growth conditions, but attachment or aggregation could be induced by different stresses. The strongest biofilm formation was observed with the addition of sodium chloride. After 3 days of incubation, the biomass volume attached to a plastic surface was 20 times higher with than without the addition of 200 mM NaCl to the medium. The addition of NaCl also resulted in biofilm formation on glass, graphite and glassy carbon, the latter two being often used electrode materials for microbial electrosynthesis. Biofilms were composed of extracellular proteins, polysaccharides, as well as DNA, while pilus-like appendages were observed with, but not without, the addition of NaCl. A transcriptome analysis comparing planktonic (no NaCl) and biofilm (NaCl addition) cells showed that C. ljungdahlii coped with the salt stress by the upregulation of the general stress response, Na+ export and osmoprotectant accumulation. A potential role for poly-N-acetylglucosamines and D-alanine in biofilm formation was found. Flagellar motility was downregulated, while putative type IV pili biosynthesis genes were not expressed. Moreover, the gene expression analysis suggested the involvement of the transcriptional regulators LexA, Spo0A and CcpA in stress response and biofilm formation. This study showed that NaCl addition might be a valuable strategy to induce biofilm formation by C. ljungdahlii, which can improve the efficacy of syngas fermentation and microbial electrosynthesis applications.}, } @article {pmid28117914, year = {2017}, author = {Dostie, S and Alkadi, LT and Owen, G and Bi, J and Shen, Y and Haapasalo, M and Larjava, HS}, title = {Chemotherapeutic decontamination of dental implants colonized by mature multispecies oral biofilm.}, journal = {Journal of clinical periodontology}, volume = {44}, number = {4}, pages = {403-409}, doi = {10.1111/jcpe.12699}, pmid = {28117914}, issn = {1600-051X}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Decontamination/*methods ; Dental Implants/*microbiology ; Humans ; Mouth/*microbiology ; Titanium ; }, abstract = {AIM: No studies have tested disinfectants on mature multispecies oral biofilms on titanium substrata. The aim of this study was to investigate the efficacy of commonly used antimicrobial agents in decontamination of multispecies mature oral biofilm on sandblasted, large-grit, acid-etched (SLA) titanium implants.

METHODS: SLA titanium disks were inoculated with dental plaque and cultured anaerobically for 21 days. The disks were rinsed with 0.9% NaCl, exposed for 2 min. to tetracycline paste, 1% Chlorhexidine gel (CHX), 35% phosphoric acid gel (Etch) or a novel chemical formula (0.3% cetrimide, 0.1% CHX and 0.5% EDTA) and then rinsed again with 0.9% NaCl. Bacteria were quantified from scanning electron micrographs of the implant surfaces. Living bacteria were quantified with confocal laser scanning microscopy (CLSM).

RESULTS AND CONCLUSIONS: Rinsing the surfaces with 0.9% NaCl removed the majority of the biofilm. However, bacteria persisted in all specimens and none of the disinfectants was superior to the double saline rinse group. CLSM analysis showed that CHX and Etch groups had a statistically significant reduction of viable bacteria, although small. Overall the results show that many disinfection agents used in the clinic are ineffective in biofilm removal and leave live bacteria on the surface.}, } @article {pmid28117413, year = {2017}, author = {Petrova, OE and Garcia-Alcalde, F and Zampaloni, C and Sauer, K}, title = {Comparative evaluation of rRNA depletion procedures for the improved analysis of bacterial biofilm and mixed pathogen culture transcriptomes.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {41114}, pmid = {28117413}, issn = {2045-2322}, mesh = {Bacteria/*genetics ; Bacterial Physiological Phenomena ; Biofilms ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/genetics/physiology ; RNA, Bacterial ; Sensitivity and Specificity ; Sequence Analysis, RNA/*methods ; Staphylococcus aureus ; }, abstract = {Global transcriptomic analysis via RNA-seq is often hampered by the high abundance of ribosomal (r)RNA in bacterial cells. To remove rRNA and enrich coding sequences, subtractive hybridization procedures have become the approach of choice prior to RNA-seq, with their efficiency varying in a manner dependent on sample type and composition. Yet, despite an increasing number of RNA-seq studies, comparative evaluation of bacterial rRNA depletion methods has remained limited. Moreover, no such study has utilized RNA derived from bacterial biofilms, which have potentially higher rRNA:mRNA ratios and higher rRNA carryover during RNA-seq analysis. Presently, we evaluated the efficiency of three subtractive hybridization-based kits in depleting rRNA from samples derived from biofilm, as well as planktonic cells of the opportunistic human pathogen Pseudomonas aeruginosa. Our results indicated different rRNA removal efficiency for the three procedures, with the Ribo-Zero kit yielding the highest degree of rRNA depletion, which translated into enhanced enrichment of non-rRNA transcripts and increased depth of RNA-seq coverage. The results indicated that, in addition to improving RNA-seq sensitivity, efficient rRNA removal enhanced detection of low abundance transcripts via qPCR. Finally, we demonstrate that the Ribo-Zero kit also exhibited the highest efficiency when P. aeruginosa/Staphylococcus aureus co-culture RNA samples were tested.}, } @article {pmid28116488, year = {2017}, author = {Cirkovic, I and Pavlovic, B and Bozic, DD and Jotic, A and Bakic, L and Milovanovic, J}, title = {Antibiofilm effects of topical corticosteroids and intranasal saline in patients with chronic rhinosinusitis with nasal polyps depend on bacterial species and their biofilm-forming capacity.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {274}, number = {4}, pages = {1897-1903}, pmid = {28116488}, issn = {1434-4726}, mesh = {Administration, Intranasal ; Adrenal Cortex Hormones/*pharmacology/therapeutic use ; Adult ; Aged ; Biofilms/*drug effects ; Chronic Disease ; Drug Therapy, Combination ; Female ; Fluticasone/pharmacology/therapeutic use ; Humans ; In Vitro Techniques ; Male ; Middle Aged ; Mometasone Furoate/pharmacology/therapeutic use ; Nasal Polyps/drug therapy/*microbiology ; Prospective Studies ; Pseudomonas aeruginosa/drug effects/isolation & purification/physiology ; Rhinitis/drug therapy/*microbiology ; Sinusitis/drug therapy/*microbiology ; Sodium Chloride/*pharmacology/therapeutic use ; Staphylococcus aureus/drug effects/isolation & purification/physiology ; Staphylococcus epidermidis/drug effects/isolation & purification/physiology ; Streptococcus pneumoniae/drug effects/isolation & purification/physiology ; }, abstract = {Microbial biofilms have been implicated in the pathogenesis of chronic rhinosinusitis with nasal polyposis (CRSwNP). Intranasal application of corticosteroids and saline is a reliable option for their management. The aim of our study was to evaluate in vitro antibiofilm effects of corticosteroids and isotonic and hypertonic nasal saline in CRSwNP patients. The sinus mucosal specimens were harvested from the ethmoid cavity of 48 patients with CRSwNP and further subjected to hematoxylin-eosin staining and microbiology analysis. The biofilm-forming capacity of isolated bacterial strains was detected by microtiter-plate method and the effects of therapeutic doses of mometasone, fluticasone, isotonic and hypertonic saline on biofilm production were investigated. Bacterial strains were isolated in 42 (87.5%) patients: one organism in 34 (80.9%) and two organisms in 8 (19.1%). Staphylococcus epidermidis (34%) and Staphylococcus aureus (28%) were the most prevalent bacteria in biofilms of CRSwNP patients. Corticosteroids and saline solutions significantly reduced biofilm formation (p < 0.01 and p < 0.05, respectively) with better efficacy of fluticasone and isotonic nasal saline. Treatment with fluticasone, mometasone, isotonic and hypertonic nasal saline completely prevented biofilm production in 66, 50, 84 and 38% of bacterial strains, respectively. The most significant density reduction was observed in biofilm formed by Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pneumoniae compared to other bacterial species (p < 0.01, p < 0.05, p < 0.05, respectively). The antibiofilm effects of corticosteroids and saline solutions also greatly depended on bacterial biomass (p < 0.05), with the most significant effect on high compared to small amount of formed biofilm. The topical steroids and nasal saline are shown to be potent antibiofilm agents in patients with CRSwNP. The effects of tested compounds depend on bacterial species and volume of formed biofilm.}, } @article {pmid28115247, year = {2017}, author = {Hirschfeld, J and Akinoglu, EM and Wirtz, DC and Hoerauf, A and Bekeredjian-Ding, I and Jepsen, S and Haddouti, EM and Limmer, A and Giersig, M}, title = {Long-term release of antibiotics by carbon nanotube-coated titanium alloy surfaces diminish biofilm formation by Staphylococcus epidermidis.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {13}, number = {4}, pages = {1587-1593}, doi = {10.1016/j.nano.2017.01.002}, pmid = {28115247}, issn = {1549-9642}, mesh = {Alloys/chemistry ; Anti-Bacterial Agents/*chemistry ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry ; Drug Liberation ; Nanotubes, Carbon/*chemistry ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/drug therapy ; Rifampin/chemistry ; Staphylococcus epidermidis/*drug effects ; Titanium/*chemistry ; }, abstract = {Bacterial biofilms cause a considerable amount of prosthetic joint infections every year, resulting in morbidity and expensive revision surgery. To address this problem, surface modifications of implant materials such as carbon nanotube (CNT) coatings have been investigated in the past years. CNTs are biologically compatible and can be utilized as drug delivery systems. In this study, multi-walled carbon nanotube (MWCNT) coated TiAl6V4 titanium alloy discs were fabricated and impregnated with Rifampicin, and tested for their ability to prevent biofilm formation over a period of ten days. Agar plate-based assays were employed to assess the antimicrobial activity of these surfaces against Staphylococcus epidermidis. It was shown that vertically aligned MWCNTs were more stable against attrition on rough surfaces than on polished TiAl6V4 surfaces. Discs with coated surfaces caused a significant inhibition of biofilm formation for up to five days. Therefore, MWCNT-modified surfaces may be effective against pathogenic biofilm formation on endoprostheses.}, } @article {pmid28114423, year = {2017}, author = {Gallique, M and Decoin, V and Barbey, C and Rosay, T and Feuilloley, MG and Orange, N and Merieau, A}, title = {Contribution of the Pseudomonas fluorescens MFE01 Type VI Secretion System to Biofilm Formation.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0170770}, pmid = {28114423}, issn = {1932-6203}, mesh = {*Biofilms ; Humans ; Mutation ; Pseudomonas fluorescens/genetics/*physiology ; Skin/microbiology ; }, abstract = {Type VI secretion systems (T6SSs) are widespread in Gram-negative bacteria, including Pseudomonas. These macromolecular machineries inject toxins directly into prokaryotic or eukaryotic prey cells. Hcp proteins are structural components of the extracellular part of this machinery. We recently reported that MFE01, an avirulent strain of Pseudomonas fluorescens, possesses at least two hcp genes, hcp1 and hcp2, encoding proteins playing important roles in interbacterial interactions. Indeed, P. fluorescens MFE01 can immobilise and kill diverse bacteria of various origins through the action of the Hcp1 or Hcp2 proteins of the T6SS. We show here that another Hcp protein, Hcp3, is involved in killing prey cells during co-culture on solid medium. Even after the mutation of hcp1, hcp2, or hcp3, MFE01 impaired biofilm formation by MFP05, a P. fluorescens strain isolated from human skin. These mutations did not reduce P. fluorescens MFE01 biofilm formation, but the three Hcp proteins were required for the completion of biofilm maturation. Moreover, a mutant with a disruption of one of the unique core component genes, MFE01ΔtssC, was unable to produce its own biofilm or inhibit MFP05 biofilm formation. Finally, MFE01 did not produce detectable N-acyl-homoserine lactones for quorum sensing, a phenomenon reported for many other P. fluorescens strains. Our results suggest a role for the T6SS in communication between bacterial cells, in this strain, under biofilm conditions.}, } @article {pmid28112955, year = {2017}, author = {Mercier, A and Gravouil, K and Aucher, W and Brosset-Vincent, S and Kadri, L and Colas, J and Bouchon, D and Ferreira, T}, title = {Fate of Eight Different Polymers under Uncontrolled Composting Conditions: Relationships Between Deterioration, Biofilm Formation, and the Material Surface Properties.}, journal = {Environmental science & technology}, volume = {51}, number = {4}, pages = {1988-1997}, doi = {10.1021/acs.est.6b03530}, pmid = {28112955}, issn = {1520-5851}, mesh = {*Biofilms ; Plastics ; Polymers/*chemistry ; Soil ; Surface Properties ; }, abstract = {With the ever-increasing volume of polymer wastes and their associated detrimental impacts on the environment, the plastic life cycle has drawn increasing attention. Here, eight commercial polymers selected from biodegradable to environmentally persistent materials, all formulated under a credit card format, were incubated in an outdoor compost to evaluate their fate over time and to profile the microbial communities colonizing their surfaces. After 450 days in compost, the samples were all colonized by multispecies biofilms, these latest displaying different amounts of adhered microbial biomass and significantly distinct bacterial and fungal community compositions depending on the substrate. Interestingly, colonization experiments on the eight polymers revealed a large core of shared microbial taxa, predominantly composed of microorganisms previously reported from environments contaminated with petroleum hydrocarbons or plastics debris. These observations suggest that biofilms may contribute to the alteration process of all the polymers studied. Actually, four substrates, independently of their assignment to a polymer group, displayed a significant deterioration, which might be attributed to biologically mediated mechanisms. Relevantly, the deterioration appears strongly associated with the formation of a high-cell density biofilm onto the polymer surfaces. The analysis of various surface properties revealed that roughness and hydrophilicity are likely prominent parameters for driving the biological interactions with the polymers.}, } @article {pmid28112658, year = {2017}, author = {Raudkivi, M and Zekker, I and Rikmann, E and Vabamäe, P and Kroon, K and Tenno, T}, title = {Nitrite inhibition and limitation - the effect of nitrite spiking on anammox biofilm, suspended and granular biomass.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {75}, number = {2}, pages = {313-321}, doi = {10.2166/wst.2016.456}, pmid = {28112658}, issn = {0273-1223}, mesh = {Anaerobiosis ; Biofilms/*growth & development ; Biomass ; Bioreactors ; Nitrites/*metabolism ; Nitrogen ; Oxidation-Reduction ; RNA, Ribosomal, 16S ; Sewage ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Anaerobic ammonium oxidation (anammox) has been studied extensively while no widely accepted optimum values for nitrite (both a substance and inhibitor) has been determined. In the current paper, nitrite spiking (abruptly increasing nitrite concentration in reactor over 20 mg NO[-]2-NL[-1]) effect on anammox process was studied on three systems: a moving bed biofilm reactor (MBBR), a sequencing batch reactor (SBR) and an upflow anaerobic sludge blanket (UASB). The inhibition thresholds and concentrations causing 50% of biomass activity decrease (IC50) were determined in batch tests. The results showed spiked biomass to be less susceptible to nitrite inhibition. Although the values of inhibition threshold and IC50 concentrations were similar for non-spiked biomass (81 and 98 mg NO[-]2-NL[-1], respectively, for SBR), nitrite spiking increased IC50 considerably (83 and 240 mg NO[-]2-NL[-1], respectively, for UASB). As the highest total nitrogen removal rate was also measured at the aforementioned thresholds, there is basis to suggest stronger limiting effect of nitrite on anammox process than previously reported. The quantitative polymerase chain reaction analysis showed similar number of anammox 16S rRNA copies in all reactors, with the lowest quantity in SBR and the highest in MBBR (3.98 × 10[8] and 1.04 × 10[9] copies g[-1] TSS, respectively).}, } @article {pmid28111031, year = {2017}, author = {Fortunato, L and Leiknes, T}, title = {In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping.}, journal = {Bioresource technology}, volume = {229}, number = {}, pages = {231-235}, doi = {10.1016/j.biortech.2017.01.021}, pmid = {28111031}, issn = {1873-2976}, mesh = {*Biofilms/growth & development ; *Biofouling ; Filtration/instrumentation/methods ; Imaging, Three-Dimensional/*methods ; Membranes, Artificial ; Tomography, Optical Coherence/*methods ; Water Purification/instrumentation/methods ; }, abstract = {Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in-situ and non-destructively. The OCT biofilm thickness map is presented for the first time as a tool to assess biofilm spatial distribution on a surface. The map allows the visualization and evaluation of the biofilm formation and growth in membrane filtration systems through the use of a false color scale. The biofilm development was monitored with OCT to evaluate the suitability of the proposed approach. A 3D time series analysis of biofilm development in a spacer filled channel representative of a spiral-wound membrane element was performed. The biofilm thickness map enables the time-resolved and spatial-resolved evaluation and visualization of the biofilm deposition pattern in-situ non-destructively.}, } @article {pmid28110918, year = {2017}, author = {Abouelhassan, Y and Yang, Q and Yousaf, H and Nguyen, MT and Rolfe, M and Schultz, GS and Huigens, RW}, title = {Nitroxoline: a broad-spectrum biofilm-eradicating agent against pathogenic bacteria.}, journal = {International journal of antimicrobial agents}, volume = {49}, number = {2}, pages = {247-251}, doi = {10.1016/j.ijantimicag.2016.10.017}, pmid = {28110918}, issn = {1872-7913}, mesh = {Acinetobacter baumannii/*drug effects/physiology ; Anti-Infective Agents, Urinary/*pharmacology ; Biofilms/*drug effects ; Humans ; Nitroquinolines/*pharmacology ; Staphylococcus/*drug effects/physiology ; Vancomycin-Resistant Enterococci/*drug effects/physiology ; }, abstract = {Bacterial biofilms are surface-attached communities of slow-growing or non-replicating bacteria tolerant to conventional antibiotic therapies. Although biofilms are known to occur in ca. 80% of all bacterial infections, no therapeutic agent has been developed to eradicate bacteria housed within biofilms. We have discovered that nitroxoline, an antibacterial agent used to treat urinary tract infections, displays broad-spectrum biofilm-eradicating activities against major human pathogens, including drug-resistant Staphylococcus aureus and Acinetobacter baumannii strains. In this study, the effectiveness of nitroxoline to eradicate biofilms was determined using an in vitro [minimum biofilm eradication concentration (MBEC) = 46.9 µM against A. baumannii] and ex vivo porcine skin model (2-3 log reduction in viable biofilm cells). Nitroxoline was also found to eradicate methicillin-resistant S. aureus (MRSA) persister cells in non-biofilm (stationary) cultures, whereas vancomycin and daptomycin were found to be inactive. These findings could lead to effective, nitroxoline-based therapies for biofilm-associated infections.}, } @article {pmid28110777, year = {2017}, author = {Xiao, G and Tang, H and Zhang, S and Ren, H and Dai, J and Lai, L and Lu, C and Yao, H and Fan, H and Wu, Z}, title = {Streptococcus suis small RNA rss04 contributes to the induction of meningitis by regulating capsule synthesis and by inducing biofilm formation in a mouse infection model.}, journal = {Veterinary microbiology}, volume = {199}, number = {}, pages = {111-119}, doi = {10.1016/j.vetmic.2016.12.034}, pmid = {28110777}, issn = {1873-2542}, mesh = {Animals ; Bacterial Adhesion ; Bacterial Capsules/genetics/metabolism ; *Biofilms ; Brain/microbiology ; Disease Models, Animal ; Female ; Gene Expression Regulation ; *Host-Pathogen Interactions ; Lung/microbiology ; Meningitis/*microbiology ; Mice ; Mice, Inbred BALB C ; RNA, Bacterial/*metabolism ; Streptococcal Infections/*microbiology/mortality/pathology ; Streptococcus suis/genetics/pathogenicity/*physiology ; Virulence Factors/genetics/metabolism ; }, abstract = {Streptococcus suis (SS) is an important pathogen for pigs, and it is also considered as a zoonotic agent for humans. Meningitis is one of the most common features of the infection caused by SS, but little is known about the mechanisms of SS meningitis. Recent studies have revealed that small RNAs (sRNAs) have emerged as key regulators of the virulence in several bacteria. In the previous study, we reported that SS sRNA rss04 was up-regulated in pig cerebrospinal fluid and contributes to SS virulence in a zebrafish infection model. Here, we show that rss04 facilitates SS invasion of mouse brain and lung in vivo. Label-free quantitation mass spectrometry analysis revealed that rss04 regulates transcriptional regulator CcpA and several virulence factors including LuxS. Transmission electron microscope and Dot-blot analyses indicated that rss04 represses capsular polysaccharide (CPS) production, which in turn facilitates SS adherence and invasion of mouse brain microvascular endothelial cells bEnd.3 in vitro and activates the mRNA expression of TLR2, CCL2, IL-6 and TNF-α in mouse brain in vivo at 12h post-infection. In addition, rss04 positively regulates SS biofilm formation. Survival analysis of infected mice showed that biofilm state in brain contributes to SS virulence by intracranial subarachnoidal route of infection. Together, our data reveal that SS sRNA rss04 contributes to the induction of meningitis by regulating the CPS synthesis and by inducing biofilm formation, thereby increasing the virulence in a mouse infection model. To our knowledge, rss04 represents the first bacterial sRNA that plays definitive roles in bacterial meningitis.}, } @article {pmid28110397, year = {2017}, author = {Wang, YQ and Yu, SJ and Zhang, F and Xia, XY and Zeng, RJ}, title = {Enhancement of acetate productivity in a thermophilic (55 °C) hollow-fiber membrane biofilm reactor with mixed culture syngas (H2/CO2) fermentation.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {6}, pages = {2619-2627}, doi = {10.1007/s00253-017-8124-9}, pmid = {28110397}, issn = {1432-0614}, mesh = {Acetic Acid/*metabolism ; Batch Cell Culture Techniques ; Biofilms/growth & development ; Bioreactors ; Butyric Acid/metabolism ; Carbon Dioxide/*metabolism ; Fermentation ; High-Throughput Nucleotide Sequencing ; Hydrogen/*metabolism ; Microbial Consortia/*genetics ; Sewage/chemistry/*microbiology ; Thermoanaerobacterium/*genetics/metabolism ; }, abstract = {Conversion of organic wastes to syngas is an attractive way to utilize wastes. The produced syngas can be further used to produce a variety of chemicals. In this study, a hollow-fiber membrane biofilm reactor with mix cultures was operated at 55 °C to convert syngas (H2/CO2) into acetate. A high concentration of acetate (42.4 g/L) was reached in batch experiment while a maximum acetate production rate of 10.5 g/L/day was achieved in the continuous-flow mode at hydraulic retention time (HRT) of 1 day. Acetate was the main product in both batch and continuous-flow experiments. n-Butyrate was the other byproduct in the reactor. Acetate accounted for more than 98.5 and 99.1% of total volatile fatty acids in batch and continuous modes, respectively. Illumina Miseq high-throughput sequencing results showed that microorganisms were highly purified and enriched in the reactor. The main genus was Thermoanaerobacterium (66% of relative abundance), which was usually considered as H2 producer in the literature, however, likely played a role as a H2 consumer in this study. This study provides a new method to generate the high producing rate and purity of acetate from syngas.}, } @article {pmid28108888, year = {2017}, author = {Proia, L and Romaní, A and Sabater, S}, title = {Biofilm phosphorus uptake capacity as a tool for the assessment of pollutant effects in river ecosystems.}, journal = {Ecotoxicology (London, England)}, volume = {26}, number = {2}, pages = {271-282}, pmid = {28108888}, issn = {1573-3017}, mesh = {*Bacterial Physiological Phenomena ; *Biofilms ; Environmental Monitoring/*methods ; Phosphorus/*metabolism ; Rivers/chemistry/microbiology ; Spain ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Biofilms are a key component in the nutrient removal from the water column. However, nutrient uptake by biofilms may be hampered by the occurrence of pollutants or other stressors. This study aimed: (i) to investigate the biofilm phosphorus (P) uptake capacity as a relevant process for the maintenance of fluvial water quality and (ii) to explore the sensitivity of this process to different chemical and environmental stressors. We conducted chamber experiments to test for the relevance of biofilm P uptake capacity (PUC) as a tool to detect effects of pollutants on river self-depuration. PUC was calculated by measuring P temporal decay after performing controlled P-spikes in chambers with biofilm-colonized tiles. Four different experiments were conducted to evaluate the response of PUC to: (a) several river waters from increasing polluted sites; (b) the effect of the bactericide triclosan (TCS); (c) the combined effect of TCS and grazers; and (d) the effect of TCS after a drought episode that affected the biofilms. These experiments showed that biofilms decreased their PUC along the pollution gradient. The biofilm PUC was significantly reduced after receiving high TCS concentrations, though lower TCS concentrations also affected the biofilm when this was submitted to grazing pressure. PUC decrease was induced by flow interruption which further enhanced the TCS negative effects. Overall, PUC was sensitive to the effects of pollutants like TCS as well as to the action of biological (grazing) and environmental (drought) factors. The study also showed that multiple stressors enhance the negative effects of pollutants on the PUC of biofilms. Our study values the use of biofilms' PUC as a sensitive ecological-based tool to assess the effects of chemicals on freshwater communities and their derived functioning in river ecosystems.}, } @article {pmid28106774, year = {2017}, author = {Zhang, N and Zhang, K and Melo, MA and Weir, MD and Xu, DJ and Bai, Y and Xu, HH}, title = {Effects of Long-Term Water-Aging on Novel Anti-Biofilm and Protein-Repellent Dental Composite.}, journal = {International journal of molecular sciences}, volume = {18}, number = {1}, pages = {}, pmid = {28106774}, issn = {1422-0067}, mesh = {Acrylic Resins/*pharmacology ; Adsorption ; Biofilms/*drug effects ; Colony-Forming Units Assay ; Composite Resins/*pharmacology ; Lactic Acid/metabolism ; Methacrylates/pharmacology ; Microbial Viability/drug effects ; Phosphorylcholine/analogs & derivatives/pharmacology ; Polyurethanes/*pharmacology ; Proteins/*chemistry ; Water/*pharmacology ; }, abstract = {The aims of this study were to: (1) synthesize an anti-biofilm and protein-repellent dental composite by combining 2-methacryloyloxyethyl phosphorylcholine (MPC) with quaternary ammonium dimethylaminohexadecyl methacrylate (DMAHDM); and (2) evaluate the effects of water-aging for 180 days on protein resistance, bacteria-killing ability, and mechanical properties of MPC-DMAHDM composite. MPC and DMAHDM were added into a resin composite. Specimens were stored in distilled water at 37 °C for 1, 30, 90, and 180 days. Mechanical properties were measured in three-point flexure. Protein attachment onto the composite was evaluated by a micro bicinchoninic acid approach. An oral plaque microcosm biofilm model was employed to evaluate oral biofilm viability vs. water-aging time. Mechanical properties of the MPC-DMAHDM composite after 180-day immersion matched those of the commercial control composite. The composite with 3% MPC + 1.5% DMAHDM had much stronger resistance to protein adhesion than control (p < 0.05). MPC + DMAHDM achieved much stronger biofilm-eradicating effects than MPC or DMAHDM alone (p < 0.05). Biofilm colony-forming units on the 3% MPC + 1.5% DMAHDM composite were three orders of magnitude lower than commercial control. The protein-repellent and antibacterial effects were durable and showed no loss in water-aging from 1 to 180 days. The novel MPC-DMAHDM composite possessed strong and durable resistance to protein adhesion and potent bacteria-eradicating function, while matching the load-bearing ability of a commercial dental composite. The novel MPC-DMAHDM composite represents a promising means of suppressing oral plaque growth, acid production, and secondary caries.}, } @article {pmid28106311, year = {2017}, author = {Puligundla, P and Mok, C}, title = {Potential applications of nonthermal plasmas against biofilm-associated micro-organisms in vitro.}, journal = {Journal of applied microbiology}, volume = {122}, number = {5}, pages = {1134-1148}, doi = {10.1111/jam.13404}, pmid = {28106311}, issn = {1365-2672}, mesh = {Bacteria/growth & development/*radiation effects ; Biofilms/growth & development/*radiation effects ; Disinfection/instrumentation/*methods ; Fungi/growth & development/*radiation effects ; }, abstract = {Biofilms as complex microbial communities attached to surfaces pose several challenges in different sectors, ranging from food and healthcare to desalination and power generation. The biofilm mode of growth allows microorganisms to survive in hostile environments and biofilm cells exhibit distinct physiology and behaviour in comparison with their planktonic counterparts. They are ubiquitous, resilient and difficult to eradicate due to their resistant phenotype. Several chemical-based cleaning and disinfection regimens are conventionally used against biofilm-dwelling micro-organisms in vitro. Although such approaches are generally considered to be effective, they may contribute to the dissemination of antimicrobial resistance and environmental pollution. Consequently, advanced green technologies for biofilm control are constantly emerging. Disinfection using nonthermal plasmas (NTPs) is one of the novel strategies having a great potential for control of biofilms of a broad spectrum of micro-organisms. This review discusses several aspects related to the inactivation of biofilm-associated bacteria and fungi by different types of NTPs under in vitro conditions. A brief introduction summarizes prevailing methods in biofilm inactivation, followed by introduction to gas discharge plasmas, active plasma species and their inactivating mechanism. Subsequently, significance and aspects of NTP inactivation of biofilm-associated bacteria, especially those of medical importance, including opportunistic pathogens, oral pathogenic bacteria, foodborne pathogens and implant bacteria, are discussed. The remainder of the review discusses majorly about the synergistic effect of NTPs and their activity against biofilm-associated fungi, especially Candida species.}, } @article {pmid28105433, year = {2016}, author = {Ueno, M and Miyamoto, H and Tsukamoto, M and Eto, S and Noda, I and Shobuike, T and Kobatake, T and Sonohata, M and Mawatari, M}, title = {Silver-Containing Hydroxyapatite Coating Reduces Biofilm Formation by Methicillin-Resistant Staphylococcus aureus In Vitro and In Vivo.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {8070597}, pmid = {28105433}, issn = {2314-6141}, mesh = {Animals ; Biofilms/*drug effects ; *Coated Materials, Biocompatible/chemistry/pharmacology ; *Durapatite/chemistry/pharmacology ; Humans ; Male ; *Materials Testing ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Rats ; Rats, Sprague-Dawley ; *Silver/chemistry/pharmacology ; }, abstract = {Biofilm-producing bacteria are the principal causes of infections associated with orthopaedic implants. We previously reported that silver-containing hydroxyapatite (Ag-HA) coatings exhibit high antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). In the present study, we evaluated the effects of Ag-HA coating of implant surfaces on biofilm formation. Titanium disks (14-mm diameter, 1-mm thickness), one surface of which was coated with HA or 0.5%-3.0% Ag-HA with a thermal spraying technique, were used. In vitro, the disks were inoculated with an MRSA suspension containing 4 × 10[5] CFU and incubated for 1-2 weeks. In vivo, MRSA-inoculated HA and 3% Ag-HA disks (8.8-10.0 × 10[8] CFU) were implanted subcutaneously on the back of rats for 1-7 days. All disks were subsequently stained with a biofilm dye and observed under a fluorescence microscope, and biofilm coverage rates (BCRs) were calculated. The BCRs on the Ag-HA coating were significantly lower than those on the HA coating at all time points in vitro (p < 0.05). Similar results were observed in vivo (p < 0.001) without argyria. Ag-HA coating reduced biofilm formation by MRSA in vitro and in vivo; therefore, Ag-HA coating might be effective for reducing implant-associated infections.}, } @article {pmid28105272, year = {2017}, author = {Vermote, A and Brackman, G and Risseeuw, MD and Cappoen, D and Cos, P and Coenye, T and Van Calenbergh, S}, title = {Novel Potentiators for Vancomycin in the Treatment of Biofilm-Related MRSA Infections via a Mix and Match Approach.}, journal = {ACS medicinal chemistry letters}, volume = {8}, number = {1}, pages = {38-42}, pmid = {28105272}, issn = {1948-5875}, abstract = {A library of 52 hamamelitannin analogues was synthesized and investigated for its ability to potentiate the effect of vancomycin toward Staphylococcus aureus biofilms. Several compounds were found to effectively increase the susceptibility of staphylococcal biofilms toward this glycopeptide. The most active analogue identified in this study showed an EC50 value of 0.26 μM.}, } @article {pmid28102347, year = {2017}, author = {Fernández, L and González, S and Campelo, AB and Martínez, B and Rodríguez, A and García, P}, title = {Low-level predation by lytic phage phiIPLA-RODI promotes biofilm formation and triggers the stringent response in Staphylococcus aureus.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {40965}, pmid = {28102347}, issn = {2045-2322}, mesh = {*Bacteriolysis ; Biofilms/*growth & development ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Host-Parasite Interactions ; Sequence Analysis, RNA ; Staphylococcus Phages/*growth & development ; Staphylococcus aureus/*physiology/*virology ; *Stress, Physiological ; }, abstract = {An important lesson from the war on pathogenic bacteria has been the need to understand the physiological responses and evolution of natural microbial communities. Bacterial populations in the environment are generally forming biofilms subject to some level of phage predation. These multicellular communities are notoriously resistant to antimicrobials and, consequently, very difficult to eradicate. This has sparked the search for new therapeutic alternatives, including phage therapy. This study demonstrates that S. aureus biofilms formed in the presence of a non-lethal dose of phage phiIPLA-RODI exhibit a unique physiological state that could potentially benefit both the host and the predator. Thus, biofilms formed under phage pressure are thicker and have a greater DNA content. Also, the virus-infected biofilm displayed major transcriptional differences compared to an untreated control. Significantly, RNA-seq data revealed activation of the stringent response, which could slow down the advance of the bacteriophage within the biofilm. The end result would be an equilibrium that would help bacterial cells to withstand environmental challenges, while maintaining a reservoir of sensitive bacterial cells available to the phage upon reactivation of the dormant carrier population.}, } @article {pmid28100054, year = {2017}, author = {Heidari Zare, H and Juhart, V and Vass, A and Franz, G and Jocham, D}, title = {Efficacy of silver/hydrophilic poly(p-xylylene) on preventing bacterial growth and biofilm formation in urinary catheters.}, journal = {Biointerphases}, volume = {12}, number = {1}, pages = {011001}, doi = {10.1116/1.4974197}, pmid = {28100054}, issn = {1559-4106}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/chemistry ; Escherichia coli/*drug effects/physiology ; Humans ; Polymers/*pharmacology ; Silver/*pharmacology ; Staphylococcus/*drug effects/physiology ; Surface Properties ; Urinary Catheters/*microbiology ; Xylenes/*pharmacology ; }, abstract = {Catheter associated urinary tract infections (CAUTI), caused by several strains of bacteria, are a common complication for catheterized patients. This may eventually lead to a blockage of the catheter due to the formation of a crystalline or amorphous biofilm. Inhibiting bacteria should result in a longer application time free of complaints. This issue has been investigated using an innovative type of silver-coated catheter with a semipermeable cap layer to prevent CAUTI. In this work, two different types of silver catheters were investigated, both of which were capped with poly(p-xylylene) (PPX-N) and exhibited different surface properties that completely changed their wetting conduct with water. The contact angle of conventionally deposited PPX-N is approximately 80°. After O2 plasma treatment, the contact angle drops to approximately 30°. These two systems, Ag/PPX-N and Ag/PPX-N-O2, were tested in synthetic urine at a body temperature of 37 °C. First, the optical density and the inhibition zones of both bacteria strains (Escherichia coli and Staphylococcus cohnii) were examined to confirm the antibacterial effect of these silver-coated catheters. Afterward, the efficacy of silver catheters with different treatments of biofilm formed by E. coli and S. cohnii were tested with crystal violet staining assays. To estimate the life cycles of silver/PPX-catheters, the eluted amount of silver was assessed at several time intervals by anodic stripping voltammetry. The silver catheter with hydrophilic PPX-N coating limited bacterial growth in synthetic urine and prevented biofilm formation. The authors attribute the enhanced bacteriostatic effect to increased silver ion release detected under these conditions. With this extensive preparatory analytic work, the authors studied the ability of the two different cap layers (without silver), PPX-N and oxygen plasma treated PPX-N, to control the growth of a crystalline biofilm by measuring the concentrations of the Ca[2+] and Mg[2+] ions after exposure of the catheters to saturated urine for 24 h. The higher concentrations of Ca[2+] and Mg[2+] in the precipitates on the PPX-N catheters indicates that the hydrophilic PPX-N coating is superior to the simple PPX-N coating, with regard to the formation of a crystalline biofilm. Moreover, hydrophilic PPX-N as a cap layer may promote wettability and increase silver ion release rate and thus reduce the adhesion of suspended crystals to the catheter. Reduced bacterial growth and reduced adhesion may help to prevent CAUTI.}, } @article {pmid28099994, year = {2017}, author = {Kodori, M and Douraghi, M and Yaseri, M and Rahbar, M}, title = {The impact of primer sets on detection of the gene encoding biofilm-associated protein (Bap) in Acinetobacter baumannii: in silico and in vitro analysis.}, journal = {Letters in applied microbiology}, volume = {64}, number = {4}, pages = {304-308}, doi = {10.1111/lam.12717}, pmid = {28099994}, issn = {1472-765X}, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/*genetics/physiology ; Bacterial Proteins/genetics ; *Biofilms ; DNA Primers/*genetics ; Humans ; Iran ; Polymerase Chain Reaction ; Sensitivity and Specificity ; Virulence Factors/*genetics ; }, abstract = {UNLABELLED: The Acinetobacter baumannii virulence protein Bap is encoded by a large gene and contains both variable sequence and repetitive modules. To date, four primer sets targeting different regions of bap have been designed, but no study has evaluated all these primers simultaneously for detection of bap. Here, we assessed the effect of primer sets Bap I-IV, on detection of bap both in silico and in vitro. Using the primer set Bap II, all 143 tested strains yielded an amplicon corresponding to the bap gene. This primer set showed the highest sensitivity (100, 95% CI: 97·9-100%) compared to the other primer sets. This study demonstrates that primer set Bap II performs with optimal efficiency for detection of the bap gene among different strains.

This study investigated the effect of nucleotide variation on PCR detection of the bap gene in various Acinetobacter baumannii strains. Since bap is the target gene for many detection assays, this variation can affect the detection efficiency. Here we present a primer set Bap II with optimal detection efficiency amongst 143 different strains, as shown by in silico and in vitro evidence.}, } @article {pmid28099040, year = {2017}, author = {Parai, D and Islam, E and Mitra, J and Mukherjee, SK}, title = {Effect of Bacoside A on growth and biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa.}, journal = {Canadian journal of microbiology}, volume = {63}, number = {2}, pages = {169-178}, doi = {10.1139/cjm-2016-0365}, pmid = {28099040}, issn = {1480-3275}, mesh = {Anti-Infective Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Saponins/*pharmacology ; Staphylococcus aureus/*drug effects ; Triterpenes/*pharmacology ; }, abstract = {The goal of this study was to evaluate the antibiofilm and antimicrobial activities of Bacoside A, a formulation of phytochemicals from Bacopa monnieri, against Staphylococcus aureus and Pseudomonas aeruginosa, which are known to form biofilms as one of their virulence traits. The antimicrobial effects of Bacoside A were tested using the minimum inhibitory concentration and minimum bactericidal concentration assays. A cell membrane disruption assay was performed to find its possible target site. MTT assay, crystal violet assay, and microscopic studies were performed to assess the antibiofilm activity. Bacoside A showed antimicrobial activity against both test organisms in their planktonic and biofilm states. At a subminimum inhibitory concentration of 200 μg·mL[-1], Bacoside A significantly removed ∼88%-93% of bacterial biofilm developed on microtiter plates. Biochemical and microscopic studies suggested that the eradication of biofilm might be due to the loss of extracellular polymeric substances and to a change in cell membrane integrity of the selected bacterial strains treated with Bacoside A. These results indicate that Bacoside A might be considered as an antimicrobial having the ability to disrupt biofilms. Thus, either alone or in combination with other therapeutics, Bacoside A could be useful to treat biofilm-related infections caused by opportunistic bacterial pathogens.}, } @article {pmid28098553, year = {2017}, author = {Sherry, L and Ramage, G and Kean, R and Borman, A and Johnson, EM and Richardson, MD and Rautemaa-Richardson, R}, title = {Biofilm-Forming Capability of Highly Virulent, Multidrug-Resistant Candida auris.}, journal = {Emerging infectious diseases}, volume = {23}, number = {2}, pages = {328-331}, pmid = {28098553}, issn = {1080-6059}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*growth & development ; Candida/*drug effects/*pathogenicity ; Candidiasis/*microbiology ; *Drug Resistance, Multiple, Fungal ; Larva/microbiology ; Microbial Sensitivity Tests ; Moths/microbiology ; Virulence ; }, abstract = {The emerging multidrug-resistant yeast pathogen Candida auris has attracted considerable attention as a source of healthcare-associated infections. We report that this highly virulent yeast has the capacity to form antifungal resistant biofilms sensitive to the disinfectant chlorhexidine in vitro.}, } @article {pmid28096965, year = {2016}, author = {Salehzadeh, A and Zamani, H and Langeroudi, MK and Mirzaie, A}, title = {Molecular typing of nosocomial Staphylococcus aureus strains associated to biofilm based on the coagulase and protein A gene polymorphisms.}, journal = {Iranian journal of basic medical sciences}, volume = {19}, number = {12}, pages = {1325-1330}, pmid = {28096965}, issn = {2008-3866}, abstract = {OBJECTIVES: Staphylococcus aureus is an important bacterial pathogen responsible for a variety numbers of nosocomial and community acquired infections. Biofilm formation is regarded as an important factor in the establishment of S. aureus infection. The contribution of the genetic background of S. aureus to biofilm formation is poorly understood. The aim of the present work was to genotype S. aureus strains associated to biofilm based on the coagulase and protein A genes and to evaluate the association between the genetic background and the biofilm forming ability of clinical S. aureus isolates.

MATERIALS AND METHODS: A total number of 100 S. aureus were isolated from nosocomial infections and biofilm formation capability was investigated using phenotypic assay and molecular detection of biofilm associated genes. The strains were genotyped based on coagulase (coa) and protein A (spa) gene polymorphisms using restriction fragments length polymorphism-polymerase chain reaction (RFLP-PCR).

RESULTS: RFLP-PCR of coa gene generated two types and three subtypes. Amplification of spa gene resulted in two banding patterns and their restriction digestion generated three subtypes. The combined coa and spa RFLP patterns generated nine genotypes (G1-G9). The genotypes G4 and G1 were the most prevalent (32.1% and 24.3%, respectively).

CONCLUSION: High clonal diversity of S. aureus strains able to produce biofilm was observed. Biofilm formation correlates with the spa and coa clonal lineage in our population and testing for multiple gene polymorphisms could be employed for local epidemiologic purposes.}, } @article {pmid28096183, year = {2017}, author = {Wren, JT and Blevins, LK and Pang, B and Basu Roy, A and Oliver, MB and Reimche, JL and Wozniak, JE and Alexander-Miller, MA and Swords, WE}, title = {Pneumococcal Neuraminidase A (NanA) Promotes Biofilm Formation and Synergizes with Influenza A Virus in Nasal Colonization and Middle Ear Infection.}, journal = {Infection and immunity}, volume = {85}, number = {4}, pages = {}, pmid = {28096183}, issn = {1098-5522}, support = {R01 DC010051/DC/NIDCD NIH HHS/United States ; T32 AI007401/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacterial Adhesion ; *Biofilms ; Disease Models, Animal ; Enzyme Activation ; Female ; Influenza A virus/*physiology ; Mice ; Nasal Mucosa/microbiology ; Neuraminidase/genetics/*metabolism ; Otitis Media/*microbiology/*virology ; Streptococcus pneumoniae/*physiology ; *Symbiosis ; }, abstract = {Even in the vaccine era, Streptococcus pneumoniae (the pneumococcus) remains a leading cause of otitis media, a significant public health burden, in large part because of the high prevalence of nasal colonization with the pneumococcus in children. The primary pneumococcal neuraminidase, NanA, which is a sialidase that catalyzes the cleavage of terminal sialic acids from host glycoconjugates, is involved in both of these processes. Coinfection with influenza A virus, which also expresses a neuraminidase, exacerbates nasal colonization and disease by S. pneumoniae, in part via the synergistic contributions of the viral neuraminidase. The specific role of its pneumococcal counterpart, NanA, in this interaction, however, is less well understood. We demonstrate in a mouse model that NanA-deficient pneumococci are impaired in their ability to cause both nasal colonization and middle ear infection. Coinfection with neuraminidase-expressing influenza virus and S. pneumoniae potentiates both colonization and infection but not to wild-type levels, suggesting an intrinsic role of NanA. Using in vitro models, we show that while NanA contributes to both epithelial adherence and biofilm viability, its effect on the latter is actually independent of its sialidase activity. These data indicate that NanA contributes both enzymatically and nonenzymatically to pneumococcal pathogenesis and, as such, suggest that it is not a redundant bystander during coinfection with influenza A virus. Rather, its expression is required for the full synergism between these two pathogens.}, } @article {pmid28092956, year = {2017}, author = {Emerenini, BO and Sonner, S and Eberl, HJ}, title = {Mathematical analysis of a quorum sensing induced biofilm dispersal model and numerical simulation of hollowing effects.}, journal = {Mathematical biosciences and engineering : MBE}, volume = {14}, number = {3}, pages = {625-653}, doi = {10.3934/mbe.2017036}, pmid = {28092956}, issn = {1551-0018}, mesh = {*Biofilms ; Biomass ; Computer Simulation ; *Models, Biological ; *Quorum Sensing ; }, abstract = {We analyze a mathematical model of quorum sensing induced biofilm dispersal. It is formulated as a system of non-linear, density-dependent, diffusion-reaction equations. The governing equation for the sessile biomass comprises two non-linear diffusion effects, a degeneracy as in the porous medium equation and fast diffusion. This equation is coupled with three semi-linear diffusion-reaction equations for the concentrations of growth limiting nutrients, autoinducers, and dispersed cells. We prove the existence and uniqueness of bounded non-negative solutions of this system and study the behavior of the model in numerical simulations, where we focus on hollowing effects in established biofilms.}, } @article {pmid28091991, year = {2018}, author = {Baudrimont, M and Andrei, J and Mornet, S and Gonzalez, P and Mesmer-Dudons, N and Gourves, PY and Jaffal, A and Dedourge-Geffard, O and Geffard, A and Geffard, O and Garric, J and Feurtet-Mazel, A}, title = {Trophic transfer and effects of gold nanoparticles (AuNPs) in Gammarus fossarum from contaminated periphytic biofilm.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {12}, pages = {11181-11191}, pmid = {28091991}, issn = {1614-7499}, mesh = {Amphipoda/*drug effects ; Animals ; Biofilms/*drug effects ; Gold/chemistry/*pharmacology ; Metal Nanoparticles/chemistry ; Microscopy, Electron, Transmission ; }, abstract = {This work addressed the trophic transfer and effects of functionalized gold nanoparticles (AuNPs) from periphytic biofilms to the crustacean Gammarus fossarum. Biofilms were exposed for 48 h to 10 nm positively charged functionalized AuNPs at two concentrations, 4.6 and 46 mg/L, and crustaceans G. fossarum grazed on these for 7 days, with daily biofilm renewal. Gold bioaccumulation in biofilm and crustacean were measured to estimate the trophic transfer ratio of these AuNP, and, for the first time, a transcriptomic approach and transmission electron microscopy observations in the crustacean were made. These two approaches showed cellular damage caused by oxidative stress and, in particular, an impact of these AuNPs on mitochondrial respiration. Modulation of digestive enzyme activity was also observed, suggesting modifications of digestive functions. The damage due to these nanoparticles could then have vital consequences for the organisms during chronic exposure.}, } @article {pmid28088542, year = {2017}, author = {Zheng, Y and Xing, M and Cai, L and Xiao, T and Lu, Y and Jiang, J}, title = {Interaction of earthworms-microbe facilitating biofilm dewaterability performance during wasted activated sludge reduction and stabilization.}, journal = {The Science of the total environment}, volume = {581-582}, number = {}, pages = {573-581}, doi = {10.1016/j.scitotenv.2016.12.166}, pmid = {28088542}, issn = {1879-1026}, mesh = {Animals ; *Biofilms ; *Filtration ; *Oligochaeta ; *Sewage ; Water ; *Water Purification ; }, abstract = {Sludge dewaterability was chemically and morphologically explored during sewage sludge treatment by vermifiltration. The results, with a conventional biofilter (BF, no earthworms) as a control, demonstrated that the capillary suction time(CST) and specific resistance of filtration(SRF) of vermifilter (VF, with earthworms) treated sludge were 64.9±1.7s and (23.1±1.3)×10[12]m/kg,16.8% and 36.0% lower than that of the BF, respectively. Additionally, the VF could efficiently decompose loosely bound extracellular polymeric substances (LB-EPS), releasing more water trapped inside biofilm. Furthermore, the VF enable to reduce the electrostatic repulsive forces between particles, verified by 9.61±0.19mV of the absolute value of zeta potential, 19.6% lower than that of the BF. Notably, based on scanning electron microscopy (SEM) analysis, the fractal dimension (Df) of sludge floc structure stated that more small and loose sludge flocs tended to aggregate into bigger inorganic particles. Therefore sludge flocs with highly compacted structure and smooth surface can transform part of vicinal water and water of hydration into easier-removed interstitial water, improving the dewaterability.}, } @article {pmid28088288, year = {2017}, author = {Van de Vyver, H and Bovenkamp, PR and Hoerr, V and Schwegmann, K and Tuchscherr, L and Niemann, S and Kursawe, L and Grosse, C and Moter, A and Hansen, U and Neugebauer, U and Kuhlmann, MT and Peters, G and Hermann, S and Löffler, B}, title = {A Novel Mouse Model of Staphylococcus aureus Vascular Graft Infection: Noninvasive Imaging of Biofilm Development in Vivo.}, journal = {The American journal of pathology}, volume = {187}, number = {2}, pages = {268-279}, doi = {10.1016/j.ajpath.2016.10.005}, pmid = {28088288}, issn = {1525-2191}, mesh = {Animals ; Biofilms/*growth & development ; Blood Vessel Prosthesis/microbiology ; Catheter-Related Infections/*diagnostic imaging ; *Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; In Situ Hybridization, Fluorescence ; Magnetic Resonance Imaging ; Mice ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; Positron-Emission Tomography ; Staphylococcal Infections/*diagnostic imaging ; Staphylococcus aureus ; }, abstract = {Staphylococcus aureus causes very serious infections of vascular grafts. Knowledge of the molecular mechanisms of this disease is largely lacking because of the absence of representable models. Therefore, the aim of this study was to set up a mouse model of vascular graft infections that closely mimics the human situation. A catheter was inserted into the right carotid artery of mice, which acted as a vascular graft. Mice were infected i.v. using 8 different S. aureus strains, and development of the infection was followed up. Although all strains had varying abilities to form biofilm in vitro and different levels of virulence in mice, they all caused biofilm formation on the grafts. This graft infection was monitored using magnetic resonance imaging (MRI) and [18]F-fluordeoxyglucose positron emission tomography (FDG-PET). MRI allowed the quantification of blood flow through the arteries, which was decreased in the catheter after infection. FDG-PET revealed high inflammation levels at the site of the catheter after infection. This model closely resembles the situation in patients, which is characterized by a tight interplay between pathogen and host, and can therefore be used for the testing of novel treatment, diagnosis, and prevention strategies. In addition, combining MRI and PET with microscopic techniques provides an appropriate way to characterize the course of these infections and to precisely analyze biofilm development.}, } @article {pmid28087619, year = {2017}, author = {Bayramoglu, B and Toubiana, D and Gillor, O}, title = {Genome-wide transcription profiling of aerobic and anaerobic Escherichia coli biofilm and planktonic cultures.}, journal = {FEMS microbiology letters}, volume = {364}, number = {3}, pages = {}, doi = {10.1093/femsle/fnx006}, pmid = {28087619}, issn = {1574-6968}, mesh = {Aerobiosis ; Anaerobiosis ; *Biofilms ; Escherichia coli/drug effects/*genetics/growth & development/metabolism ; *Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genome, Bacterial ; Oxygen/*metabolism ; Plankton ; }, abstract = {Many studies have described the response of the facultative anaerobe, Escherichia coli, to anaerobic conditions, yet they all investigated free-living (planktonic) cells because attempts to cultivate anaerobic E. coli biofilm were mostly unsuccessful. We challenged these findings and cultivated E. coli strain MG1655 biofilm under both aerobic and anaerobic conditions, characterizing the mature biofilm architecture and global gene expression profile. We used RNA sequencing technology to compare stationary phase planktonic cells with mature biofilm, cultured with and without oxygen. Our results suggest that gene expression patterns significantly differ between biofilm and planktonic cultures cultivated under the same oxygenic conditions. The anaerobic E. coli biofilms were slow growing and patchy compared to aerobic biofilms, yet some features were unchanged like the production of extracellular polymeric substances. A closer inspection of the mRNA data revealed that essential cell processes were attenuated in anaerobic biofilms, including protein synthesis, information transfer, cell structure, regulation and transport. Our results suggest that lack of oxygen imposes severe stress on mature biofilms thus limiting the cells' activity. We further propose that E. coli does not favor growing in anaerobic biofilms and when forced to do so, the cells prevail by attenuating their activity in order to survive.}, } @article {pmid28087612, year = {2017}, author = {Srednik, ME and Tremblay, YDN and Labrie, J and Archambault, M and Jacques, M and Fernández Cirelli, A and Gentilini, ER}, title = {Biofilm formation and antimicrobial resistance genes of coagulase-negative staphylococci isolated from cows with mastitis in Argentina.}, journal = {FEMS microbiology letters}, volume = {364}, number = {8}, pages = {}, doi = {10.1093/femsle/fnx001}, pmid = {28087612}, issn = {1574-6968}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Argentina ; Biofilms/*growth & development ; Cattle ; Coagulase/genetics/metabolism ; Drug Resistance, Multiple, Bacterial/*genetics ; Female ; Genes, Bacterial ; Mastitis, Bovine/*microbiology ; Microbial Sensitivity Tests ; Polymorphism, Restriction Fragment Length ; Real-Time Polymerase Chain Reaction ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus/drug effects/genetics/isolation & purification/*physiology ; }, abstract = {Mastitis affects the health and welfare of dairy cows worldwide. Coagulase-negative staphylococci (CNS) are known to form biofilms and are increasingly recognized as a cause of persistent bovine intramammary infections. A total of 90 CNS isolated from cows with clinical and subclinical mastitis in Argentina from 2008 to 2014 were identified by PCR-RFLP using the gap gene. Standard microtiter plate assays were used to assess CNS biofilm formation, and Staphylococcus haemolyticus species formed the strongest biofilms. The presence of biofilm-associated genes icaA, bap and aap was detected in a few isolates, while embP, fbe, atlE and eno were present in the majority of isolates. Genes encoding resistance to β-lactams were detected among the isolates; blaZ, mecA and mecC were detected in 21, 4 and 1 isolate, respectively. Resistance to macrolides and lincosamides (n = 6) was attributable to ermB, ermC, mphC or mrsA or a combination of those genes. In this study, we identified CNS species involved in mastitis and provide information about pathogenicity and antimicrobial resistance, which is essential to design efficient strategies to control mastitis caused by CNS.}, } @article {pmid28087529, year = {2017}, author = {Prokhorova, A and Sturm-Richter, K and Doetsch, A and Gescher, J}, title = {Resilience, Dynamics, and Interactions within a Model Multispecies Exoelectrogenic-Biofilm Community.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {6}, pages = {}, pmid = {28087529}, issn = {1098-5336}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Coculture Techniques ; Electricity ; Electrochemical Techniques/*methods ; Electrodes/microbiology ; Electron Transport ; Geobacter/growth & development/*metabolism ; Oxidation-Reduction ; Shewanella/growth & development/*metabolism ; }, abstract = {Anode-associated multispecies exoelectrogenic biofilms are essential for the function of bioelectrochemical systems (BESs). The individual activities of anode-associated organisms and physiological responses resulting from coculturing are often hard to assess due to the high microbial diversity in these systems. Therefore, we developed a model multispecies biofilm comprising three exoelectrogenic proteobacteria, Shewanella oneidensis, Geobacter sulfurreducens, and Geobacter metallireducens, with the aim to study in detail the biofilm formation dynamics, the interactions between the organisms, and the overall activity of an exoelectrogenic biofilm as a consequence of the applied anode potential. The experiments revealed that the organisms build a stable biofilm on an electrode surface that is rather resilient to changes in the redox potential of the anode. The community operated at maximum electron transfer rates at electrode potentials that were higher than 0.04 V versus a normal hydrogen electrode. Current densities decreased gradually with lower potentials and reached half-maximal values at -0.08 V. Transcriptomic results point toward a positive interaction among the individual strains. S. oneidensis and G. sulfurreducens upregulated their central metabolisms as a response to cultivation under mixed-species conditions. G. sulfurreducens was detected in the planktonic phase of the bioelectrochemical reactors in mixed-culture experiments but not when it was grown in the absence of the other two organisms.IMPORTANCE In many cases, multispecies communities can convert organic substrates into electric power more efficiently than axenic cultures, a phenomenon that remains unresolved. In this study, we aimed to elucidate the potential mutual effects of multispecies communities in bioelectrochemical systems to understand how microbes interact in the coculture anodic network and to improve the community's conversion efficiency for organic substrates into electrical energy. The results reveal positive interactions that might lead to accelerated electron transfer in mixed-species anode communities. The observations made within this model biofilm might be applicable to a variety of nonaxenic systems in the field.}, } @article {pmid28087493, year = {2017}, author = {Merghni, A and Dallel, I and Noumi, E and Kadmi, Y and Hentati, H and Tobji, S and Ben Amor, A and Mastouri, M}, title = {Antioxidant and antiproliferative potential of biosurfactants isolated from Lactobacillus casei and their anti-biofilm effect in oral Staphylococcus aureus strains.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {84-89}, doi = {10.1016/j.micpath.2017.01.017}, pmid = {28087493}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/biosynthesis/*pharmacology ; *Antibiosis ; Antioxidants/isolation & purification/metabolism/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Cell Line ; Cell Proliferation/drug effects ; Humans ; Lacticaseibacillus casei/*metabolism ; Mouth/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; Surface-Active Agents/isolation & purification/metabolism/*pharmacology ; }, abstract = {Biosurfactants also called bioemulsifiers are amphipathic compounds produced by many microorganisms that allow them to exhibit a wide range of biological activities. The aim of this study was to determine the antioxidant and antiproliferative potential of biosurfactants isolated from Lactobacillus casei and to assess their anti-adhesive and anti-biofilm abilities against oral opportunistic Staphylococcus aureus strains. The antioxidant activity of biosurfactant was evaluated using the in vitro scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The antiproliferative activity was determined on epithelial cell line (HEp-2) by the Methylthiazole tetrazolium (MTT) reduction assay. The anti-adhesive and antibiofilm activity against S. aureus strains were achieved using crystal violet staining. Our results revealed that the DPPH scavenging activity of biosurfactants at 5.0 mg/mL concentration is between 74.6 and 77.3%. Furthermore, biosurfactants showed antiproliferative potency against studied epithelial cells as judged by IC50 and its value ranged from 109.1 ± 0.84 mg/mL to 129.7 ± 0.52 mg/mL. The results of the growth inhibition indicate that biosurfactant BS-LBl was more effective against oral S. aureus strains 9P and 29P with an IC50 of 1.92 ± 0.26 mg/mL and 2.16 ± 0.12 mg/mL respectively. Moreover, both biosurfactants displayed important antibiofilm activity with eradication percentages ranging from 80.22 ± 1.33% to 86.21 ± 2.94% for the BS-LBl, and from 53.38 ± 1.77% to 64.42 ± 2.09% for the BS-LZ9. Our findings demonstrate that biosurfactants from L. casei strains exhibited considerable antioxidant and antiproliferative potencies and were able to inhibit oral S. aureus strains with important antibiofilm efficacy. They could have a promising role in the prevention of oral diseases.}, } @article {pmid28087484, year = {2017}, author = {Xu, LC and Wo, Y and Meyerhoff, ME and Siedlecki, CA}, title = {Inhibition of bacterial adhesion and biofilm formation by dual functional textured and nitric oxide releasing surfaces.}, journal = {Acta biomaterialia}, volume = {51}, number = {}, pages = {53-65}, pmid = {28087484}, issn = {1878-7568}, support = {R01 HL069965/HL/NHLBI NIH HHS/United States ; R01 HL128337/HL/NHLBI NIH HHS/United States ; }, mesh = {Anti-Infective Agents/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Imaging, Three-Dimensional ; Least-Squares Analysis ; Microscopy, Atomic Force ; Microscopy, Fluorescence ; Nitric Oxide/*pharmacology ; Polyurethanes/pharmacology ; S-Nitroso-N-Acetylpenicillamine/pharmacology ; Water/chemistry ; Wettability ; }, abstract = {UNLABELLED: In separate prior studies, physical topographic surface modification or nitric oxide (NO) release has been demonstrated to each be an effective approach to inhibit and control bacterial adhesion and biofilm formation on polymeric surfaces. Such approaches can prevent biomaterial-associated infection without causing the antibiotic resistance of the strain. In this work, both techniques were successfully integrated and applied to a polyurethane (PU) biomaterial surface that bears ordered pillar topographies (400/400nm and 500/500nm patterns) at the top surface and a S-nitroso-N-acetylpenicillamine (SNAP, NO donor) doped sub-layer in the middle, via a soft lithography two-stage replication process. Upon placing the SNAP textured PU films into PBS at 37°C, the decomposition of SNAP within polymer film initiates NO release with a lifetime of up to 10days at flux levels >0.5×10[-10]molmin[-1]cm[-2] for a textured polyurethane layer containing 15wt% SNAP. The textured surface reduces the accessible surface area and the opportunity of bacteria-surface interaction, while the NO release from the same surface further inhibits bacterial growth and biofilm formation. Such dual functionality surfaces are shown to provide a synergistic effect on inhibition of Staphylococcus epidermidis bacterial adhesion that is significantly greater than the inhibition of bacterial adhesion achieved by either single treatment approach alone. Longer term experiments to observe biofilm formation demonstrate that the SNAP doped-textured PU surface can inhibit the biofilm formation for >28d and provide a practical approach to improve the biocompatibility of current biomimetic biomaterials and thereby reduce the risk of pathogenic infection.

STATEMENT OF SIGNIFICANCE: Microbial infection remains a significant barrier to development and implementation of advanced blood-contacting medical devices. Clearly, determining how to design and control material properties that can reduce microbial infection is a central question to biomaterial researchers. In separate prior studies, physical topographic surface modification or nitric oxide (NO) release has been demonstrated to each be an effective approach to inhibit and control bacterial adhesion and biofilm formation on polymeric surfaces. Such approaches can prevent biomaterial-associated infection without causing antibiotic resistance of the bacterial strain. However, efficiency of antimicrobial properties of each approach is still limited and far from sufficient for widespread clinical use. This work successfully integrates both techniques and applies them to a polyurethane (PU) biomaterial surface that bears dual functions, surface topographic modification and NO release. The former reduces the surface contact area and changes surface wettability, resulting in reduction of bacterial adhesion, and NO release further inhibits bacteria growth. Such dual functionalized surfaces provide a synergistic effect on inhibition of Staphylococcus epidermidis bacterial adhesion that is significantly greater than the inhibition of bacterial adhesion achieved by either single treatment approach alone. Furthermore, longer-term experiments demonstrate that the dual functionalized surfaces can inhibit biofilm formation for >28days. The success of this work provides a practical approach to improve the biocompatibility of current biomaterials and thereby reduce the risk of pathogenic infection.}, } @article {pmid28087408, year = {2017}, author = {Dusane, DH and Diamond, SM and Knecht, CS and Farrar, NR and Peters, CW and Howlin, RP and Swearingen, MC and Calhoun, JH and Plaut, RD and Nocera, TM and Granger, JF and Stoodley, P}, title = {Effects of loading concentration, blood and synovial fluid on antibiotic release and anti-biofilm activity of bone cement beads.}, journal = {Journal of controlled release : official journal of the Controlled Release Society}, volume = {248}, number = {}, pages = {24-32}, doi = {10.1016/j.jconrel.2017.01.005}, pmid = {28087408}, issn = {1873-4995}, mesh = {Anti-Bacterial Agents/*administration & dosage/pharmacology ; Biofilms/*drug effects ; Bone Cements/*chemistry ; Calcium Sulfate/chemistry ; Drug Carriers/*chemistry ; Humans ; Polymethyl Methacrylate/chemistry ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/drug effects ; Tobramycin/*administration & dosage/pharmacology ; Vancomycin/*administration & dosage/pharmacology ; }, abstract = {Antibiotic loaded cement beads are commonly used for the treatment of biofilm related orthopaedic periprosthetic infections; however the effects of antibiotic loading and exposure of beads to body fluids on release kinetics are unclear. The purpose of this study was to determine the effects of (i) antibiotic loading density (ii) loading amount (iii) material type and (iv) exposure to body fluids (blood or synovial fluid) on release kinetics and efficacy of antibiotics against planktonic and lawn biofilm bacteria. Short-term release into an agar gel was evaluated using a fluorescent tracer (fluorescein) incorporated in the carrier materials calcium sulfate (CaSO4) and poly methyl methacrylate (PMMA). Different fluorescein concentrations in CaSO4 beads were evaluated. Mechanical properties of fluorescein-incorporated beads were analyzed. Efficacy of the antibiotics vancomycin (VAN) or tobramycin (TOB) alone and in combination was evaluated against lawn biofilms of bioluminescent strains of Staphylococcus aureus and Pseudomonas aeruginosa. Zones of inhibition of cultures (ZOI) were measured visually and using an in-vivo imaging system (IVIS). The influence of body fluids on release was assessed using CaSO4 beads that contained fluorescein or antibiotics and were pre-coated with human blood or synovial fluid. The spread from the beads followed a square root of time relationship in all cases. The loading concentration had no influence on short-term fluorescein release and pre-coating of beads with body fluids did not affect short-term release or antibacterial activity. Compared to PMMA, CaSO4 had a more rapid short term rate of elution and activity against planktonic and lawn biofilms. This study highlights the importance of considering antibiotic loading and packing density when investigating the clinical application of bone cements for infection management.}, } @article {pmid28087297, year = {2017}, author = {Kim, J and Lee, HJ and Hong, SH}, title = {Inhibition of streptococcal biofilm by hydrogen water.}, journal = {Journal of dentistry}, volume = {58}, number = {}, pages = {34-39}, doi = {10.1016/j.jdent.2017.01.004}, pmid = {28087297}, issn = {1879-176X}, mesh = {Bacterial Proteins/drug effects/genetics ; Biofilms/*drug effects/growth & development ; Carrier Proteins/drug effects/genetics/metabolism ; Colony Count, Microbial ; Double-Blind Method ; Gene Expression Regulation, Bacterial/drug effects ; Genes, Bacterial/drug effects/genetics ; Glucans/genetics/metabolism ; Glucosyltransferases/drug effects/genetics/metabolism ; Humans ; Hydrogen/*pharmacology ; In Vitro Techniques ; Lectins/drug effects/genetics/metabolism ; Mouthwashes/pharmacology ; RNA, Messenger/metabolism ; Saliva/microbiology ; Streptococcus/*drug effects/enzymology/genetics/metabolism ; Streptococcus mutans/drug effects/enzymology/genetics/metabolism ; Streptococcus sobrinus/drug effects/enzymology/genetics/metabolism ; Water/*chemistry ; }, abstract = {OBJECTIVES: The accumulation of oral bacterial biofilm is the main etiological factor of oral diseases. Recently, electrolyzed hydrogen-rich water (H-water) has been shown to act as an effective antioxidant by reducing oxidative stress. In addition to this general health benefit, H-water has antibacterial activity for disease-associated oral bacteria. However, little is known about the effect of H-water on oral bacterial biofilm. The objective of this study was to confirm the effect of H-water on streptococcal biofilm formation.

METHODS: In vitro streptococcal biofilm was quantified using crystal violet staining after culture on a polystyrene plate. The effect of H-water on the expression of genes involved in insoluble glucan synthesis and glucan binding, which are critical steps for oral biofilm formation, was evaluated in MS. In addition, we compared the number of salivary streptococci after oral rinse with H-water and that with control tap water. Salivary streptococci were quantified by counting viable colonies on Mitis Salivarius agar-bacitracin.

RESULTS: Our data showed that H-water caused a significant decrease in in vitro streptococcal biofilm formation. The expression level of the mRNA of glucosyltransferases (gtfB, gtfc, and gtfI) and glucan-binding proteins (gbpC, dblB) were decreased remarkably in MS after H-water exposure for 60s. Furthermore, oral rinse with H-water for 1 week led to significantly fewer salivary streptococci than did that with control tap water.

CONCLUSIONS: Our data suggest that oral rinse with H-water would be helpful in treating dental biofilm-dependent diseases with ease and efficiency.}, } @article {pmid28084573, year = {2017}, author = {Yu, SB and Li, WG and Liu, XS and Che, J and Lu, JX and Wu, Y}, title = {The Activities of Adhesion and Biofilm Formation by Candida tropicalis Clinical Isolates Display Significant Correlation with Its Multilocus Sequence Typing.}, journal = {Mycopathologia}, volume = {182}, number = {5-6}, pages = {459-469}, pmid = {28084573}, issn = {1573-0832}, mesh = {Biofilms/*growth & development ; Candida tropicalis/classification/genetics/*isolation & purification/physiology ; Candidiasis/*microbiology ; *Cell Adhesion ; China ; *Genotype ; Humans ; *Multilocus Sequence Typing ; *Mycological Typing Techniques ; }, abstract = {Adhesion and biofilm formation, which can occur on abiotic and biotic surfaces, are key components in Candida pathogenicity. The aims of this study were to infer about the C. tropicalis clinical isolates ability to adhere and form biofilm on abiotic and biotic surfaces and to correlate that with the multilocus sequence typing and other virulence factors. Adhesion and biofilm formation were measured in 68 C. tropicalis isolates from 3 hospitals in China on abiotic (polystyrene) and biotic (human urinary bladder epithelial cell) surfaces by crystal violet assay and 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide reduction assay. In our study, almost all C. tropicalis isolates could adhere and produce biofilm on abiotic and biotic surfaces in a strain-dependent manner. The isolates from blood showed relatively lower adhesion and biofilm capacity on polystyrene surface, but had strong secreted aspartyl proteinase activity. Moreover, significant differences were found among MLST groups for adhesion and biofilm capacity. C. tropicalis in multilocus sequence typing group5 and group6 showed high adhesion and biofilm, while isolates in group1 exhibited low adhesion and biofilm formation. Overall, it is important to note that C. tropicalis isolates adhere to and produce biofilm on abiotic and biotic surfaces with strain specificity. These data will play an important role in subsequent research on the pathogenesis of C. tropicalis.}, } @article {pmid28082241, year = {2017}, author = {Qiu, T and Xu, Y and Gao, M and Han, M and Wang, X}, title = {Bacterial community dynamics in a biodenitrification reactor packed with polylactic acid/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) blend as the carbon source and biofilm carrier.}, journal = {Journal of bioscience and bioengineering}, volume = {123}, number = {5}, pages = {606-612}, doi = {10.1016/j.jbiosc.2016.12.007}, pmid = {28082241}, issn = {1347-4421}, mesh = {3-Hydroxybutyric Acid/*metabolism/pharmacology ; Betaproteobacteria/classification/genetics/isolation & purification/*metabolism ; Biodegradation, Environmental ; *Biofilms/drug effects ; Bioreactors/*microbiology ; Carbon/*metabolism/pharmacology ; Comamonadaceae/classification/genetics/isolation & purification/metabolism ; *Denitrification ; Nitrates/isolation & purification/metabolism ; Nitrogen/isolation & purification/metabolism ; Pentanoic Acids/*metabolism/pharmacology ; Polyesters/*metabolism/pharmacology ; Polymers/*metabolism/pharmacology ; RNA, Ribosomal, 16S/genetics ; Sewage/microbiology ; Wastewater/chemistry ; }, abstract = {While heterotrophic denitrification has been widely used for treating such nitrogen-rich wastewater, it requires the use of additional carbon sources. With fluctuations in the nitrate concentration in the influent, controlling the C/N ratio to avoid carbon breakthrough becomes difficult. To overcome this obstacle, solid-phase denitrification (SPD) using biodegradable polymers has been used, where denitrification and carbon source biodegradation depend on microorganisms growing within the reactor. However, the microbial community dynamics in continuous-flow SPD reactors have not been fully elucidated yet. Here, we aimed to study bacterial community dynamics in a biodenitrification reactor packed with a polylactic acid/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PLA/PHBV) blend as the carbon source and biofilm carrier. A lab-scale denitrifying reactor filled with a PLA/PHBV blend was used. With 85 mg/L of influent NO3-N concentration and a hydraulic retention time (HRT) of 2.5 h, more than 92% of the nitrate was removed. The bacterial community of inoculated activated sludge had the highest species richness in all samples. Bacterial species diversity in the reactor first decreased and then increased to a stable level. Diaphorobacter species were predominant in the reactor after day 24. In total, 178 clones were retrieved from the 16S rRNA gene clone library constructed from the biofilm samples in the reactor at 62 days of operation, and 80.9% of the clones were affiliated with Betaproteobacteria. Of these, 97.2% were classified into phylotypes corresponding to Diaphorobacter nitroreducens strain NA10B with 99% sequence similarity. Diaphorobacter, Rhizobium, Acidovorax, Rubrivivax, Azospira, Thermomonas, and Acidaminobacter constituted the biofilm microflora in the stably running reactor.}, } @article {pmid28081347, year = {2016}, author = {Kot, B and Wicha, J and Grużewska, A and Piechota, M and Wolska, K and Obrębska, M}, title = {Virulence factors, biofilm-forming ability, and antimicrobial resistance of urinary Escherichia coli strains isolated from hospitalized patients.}, journal = {Turkish journal of medical sciences}, volume = {46}, number = {6}, pages = {1908-1914}, doi = {10.3906/sag-1508-105}, pmid = {28081347}, issn = {1300-0144}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Drug Resistance, Bacterial ; Escherichia coli ; Escherichia coli Infections ; Humans ; Phylogeny ; Urinary Tract Infections ; Virulence ; Virulence Factors ; }, abstract = {BACKGROUND/AIM: Escherichia coli is the most frequent cause of urinary tract infections. We investigated the possible associations between the origin of strains, antimicrobial resistance, the presence of urovirulence factors, and biofilm-forming ability.

MATERIALS AND METHODS: Antibiotic susceptibility of E. coli strains was tested by disk diffusion method. Hemagglutination assays were performed for phenotypic characterization of the cell surface. Multiplex PCR was used for detection of virulence genes and for determination of phylogenetic relationships.

RESULTS: The resistance to ampicillin (55.5%) and tetracycline (39.3%) was significantly more frequent than to other antimicrobial agents. The fim gene was present in 92.5% of strains. The sfa and pap genes were found in 53.8% and 38.7% of strains, respectively. The pap gene was significantly less frequently detected in strains from dialysis patients. The hly gene was present in 18.5% of strains. The aer gene was detected in 52.6% and cnf in 12.1%, while afa was detected in 4.6% of strains. Most strains belonged to the B2 and D phylogenetic groups. The aer gene was significantly associated with strains producing strong biofilms.

CONCLUSION: The E. coli strains causing cystitis in hospitalized patients differed in terms of resistance to antibiotics, virulence genes, and potential for biofilm formation.}, } @article {pmid28080292, year = {2017}, author = {Bardes, JM and Gray, D and Wilson, A}, title = {Effect of the endOclear[®] Device on Biofilm in Endotracheal Tubes.}, journal = {Surgical infections}, volume = {18}, number = {3}, pages = {293-298}, doi = {10.1089/sur.2016.052}, pmid = {28080292}, issn = {1557-8674}, mesh = {Biofilms/*growth & development ; Equipment Contamination/*prevention & control ; Equipment and Supplies/*microbiology ; Female ; Hospitals, University ; Humans ; Intensive Care Units ; *Intubation, Intratracheal ; Male ; Middle Aged ; Pneumonia, Ventilator-Associated/*prevention & control ; Treatment Outcome ; }, abstract = {BACKGROUND: Organisms trapped in biofilms cause more than 80% of medical infections. Significant investments are being made to develop methods of removing these biofilms. The endOclear[®] device is reported to remove biofilm from endotracheal tubes (ETTs) and to decrease pneumonia rates and ventilator time.

METHODS: This was an observational study performed at a university Level 1 trauma center intensive care unit. A series of 40 ETTs were collected at extubation, with half of the patients having been treated daily with the endOclear[®] device. Biofilms were quantified from a standardized point on the distal ETT. The patients' standard and biofilm cultures were reviewed.

RESULTS: The mean hours of intubation for the control group was 135 and for the device group 138. This difference was not statistically significant (p = 0.91). Eleven patients in the device group were found to have pneumonia compared with six in the control group (p = 0.34). Ventilator data after device use showed a mean increase of 29.9 cc in tidal volume and a mean decrease in peak pressures of 0.39 cm H2O. Comparisons between biofilm stage or hours of intubation and a diagnosis of pneumonia found no correlation. Only nine of 40 ETTs had congruence between the microbiata of the biofilm and standard bronchoalveolar lavage (BAL) fluid, a divergence rate of 78%.

CONCLUSIONS: Comparison of the endOclear[®] group and controls demonstrated a trend toward a higher pneumonia rate in the former. Additionally, the device achieved very small, clinically insignificant, changes in ventilator settings, and no difference was seen in the time on the ventilator. Comparisons between biofilm and standard BAL cultures continue to show the biofilm is more diverse than previously thought. In this study, no statistical significance was found between biofilm stage and the pneumonia rate. This study provides additional evidence that there is no correlation between biofilm stage and duration of intubation.}, } @article {pmid28079132, year = {2017}, author = {Alfatah, M and Bari, VK and Nahar, AS and Bijlani, S and Ganesan, K}, title = {Critical role for CaFEN1 and CaFEN12 of Candida albicans in cell wall integrity and biofilm formation.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {40281}, pmid = {28079132}, issn = {2045-2322}, mesh = {Amphotericin B/pharmacology ; Biofilms/drug effects/*growth & development ; Biosynthetic Pathways/genetics ; Candida albicans/cytology/genetics/*metabolism/*physiology ; Cell Wall/drug effects/*metabolism ; Fungal Proteins/genetics/*metabolism ; Genes, Fungal ; Hyphae/drug effects/growth & development ; Microbial Sensitivity Tests ; Saccharomyces cerevisiae/genetics ; Sphingolipids/biosynthesis ; }, abstract = {Sphingolipids are involved in several cellular functions, including maintenance of cell wall integrity. To gain insight into the role of individual genes of sphingolipid biosynthetic pathway, we have screened Saccharomyces cerevisiae strains deleted in these genes for sensitivity to cell wall perturbing agents calcofluor white and congo red. Only deletants of FEN1 and SUR4 genes were found to be sensitive to both these agents. Candida albicans strains deleted in their orthologs, CaFEN1 and CaFEN12, respectively, also showed comparable phenotypes, and a strain deleted for both these genes was extremely sensitive to cell wall perturbing agents. Deletion of these genes was reported earlier to sensitise cells to amphotericin B (AmB), which is a polyene drug that kills the cells mainly by binding and sequestering ergosterol from the plasma membrane. Here we show that their AmB sensitivity is likely due to their cell wall defect. Further, we show that double deletant of C. albicans is defective in hyphae formation as well as biofilm development. Together this study reveals that deletion of FEN1 and SUR4 orthologs of C. albicans leads to impaired cell wall integrity and biofilm formation, which in turn sensitise cells to AmB.}, } @article {pmid28078398, year = {2017}, author = {Wang, C and Liu, S and Xu, X and Zhao, C and Yang, F and Wang, D}, title = {Potential coupling effects of ammonia-oxidizing and anaerobic ammonium-oxidizing bacteria on completely autotrophic nitrogen removal over nitrite biofilm formation induced by the second messenger cyclic diguanylate.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {9}, pages = {3821-3828}, doi = {10.1007/s00253-016-7981-y}, pmid = {28078398}, issn = {1432-0614}, mesh = {Ammonia/*metabolism ; Ammonium Compounds/*metabolism ; Anaerobiosis ; Bacteria/genetics/*metabolism ; Biofilms/*growth & development ; Bioreactors/microbiology ; Cyclic GMP/*analogs & derivatives/metabolism ; Denitrification ; Gene Expression Regulation, Bacterial ; Nitrites/metabolism ; Nitrogen/*metabolism ; Oxidation-Reduction ; Polysaccharides, Bacterial/metabolism ; Second Messenger Systems ; Sewage/microbiology ; }, abstract = {The objective of this study was to investigate the influence of extracellular polymeric substance (EPS) on the coupling effects between ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing (anammox) bacteria for the completely autotrophic nitrogen removal over nitrite (CANON) biofilm formation in a moving bed biofilm reactor (MBBR). Analysis of the quantity of EPS and cyclic diguanylate (c-di-GMP) confirmed that the contents of polysaccharides and c-di-GMP were correlated in the AOB sludge, anammox sludge, and CANON biofilm. The anammox sludge secreted more EPS (especially polysaccharides) than AOB with a markedly higher c-di-GMP content, which could be used by the bacteria to regulate the synthesis of exopolysaccharides that are ultimately used as a fixation matrix, for the adhesion of biomass. Indeed, increased intracellular c-di-GMP concentrations in the anammox sludge enhanced the regulation of polysaccharides to promote the adhesion of AOB and formation of the CANON biofilm. Overall, the results of this study provide new comprehensive information regarding the coupling effects of AOB and anammox bacteria for the nitrogen removal process.}, } @article {pmid28076651, year = {2017}, author = {De Cremer, K and Braem, A and Gerits, E and De Brucker, K and Vandamme, K and Martens, JA and Michiels, J and Vleugels, J and Cammue, BP and Thevissen, K}, title = {Controlled release of chlorhexidine from a mesoporous silica-containing macroporous titanium dental implant prevents microbial biofilm formation.}, journal = {European cells & materials}, volume = {33}, number = {}, pages = {13-27}, doi = {10.22203/eCM.v033a02}, pmid = {28076651}, issn = {1473-2262}, mesh = {Biofilms/drug effects/*growth & development ; Cell Line, Tumor ; Chlorhexidine/*administration & dosage/*pharmacology ; Delayed-Action Preparations ; *Dental Implants ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Osteoblasts/cytology/drug effects ; Porosity ; Prosthesis Design ; Silicon Dioxide/*chemistry ; Streptococcus mutans/drug effects/metabolism/*physiology/ultrastructure ; Titanium/*pharmacology ; }, abstract = {Roughened surfaces are increasingly being used for dental implant applications as the enlarged contact area improves bone cell anchorage, thereby facilitating osseointegration. However, the additional surface area also entails a higher risk for the development of biofilm associated infections, an etiologic factor for many dental ailments, including peri-implantitis. To overcome this problem, we designed a dental implant composed of a porous titanium-silica (Ti/SiO2) composite material and containing an internal reservoir that can be loaded with antimicrobial compounds. The composite material consists of a sol-gel derived mesoporous SiO2 diffusion barrier integrated in a macroporous Ti load-bearing structure obtained by powder metallurgical processing. The antimicrobial compounds can diffuse through the porous implant walls, thereby reducing microbial biofilm formation on the implant surface. A continuous release of µM concentrations of chlorhexidine through the Ti/SiO2 composite material was measured, without initial burst effect, over at least 10 days and using a 5 mM chlorhexidine solution in the implant reservoir. Metabolic staining, CFU counting and visualisation by scanning electron microscopy confirmed that Streptococcus mutans biofilm formation on the implant surface was almost completely prevented due to chlorhexidine release (preventive setup). Moreover, we demonstrated efficacy of released chlorhexidine against mature Streptococcus mutans biofilms (curative setup). In conclusion, we provide a proof of concept of the sustained release of chlorhexidine, one of the most widely used oral antiseptics, through the Ti/SiO2 material thereby preventing and eradicating biofilm formation on the surface of the dental implant. In principle, our flexible design allows for the use of any bioactive compound, as discussed.}, } @article {pmid28076372, year = {2017}, author = {Junka, A and Szymczyk, P and Ziółkowski, G and Karuga-Kuzniewska, E and Smutnicka, D and Bil-Lula, I and Bartoszewicz, M and Mahabady, S and Sedghizadeh, PP}, title = {Bad to the Bone: On In Vitro and Ex Vivo Microbial Biofilm Ability to Directly Destroy Colonized Bone Surfaces without Participation of Host Immunity or Osteoclastogenesis.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0169565}, pmid = {28076372}, issn = {1932-6203}, support = {L32 MD003617/MD/NIMHD NIH HHS/United States ; T90 DE021982/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/drug effects/pathogenicity/physiology ; Durapatite/pharmacology ; Jaw/*microbiology/pathology ; Male ; Osteoblasts/*microbiology/ultrastructure ; Osteomyelitis/*microbiology ; Polystyrenes/pharmacology ; Pseudomonas aeruginosa/drug effects/pathogenicity/physiology ; Rats ; Rats, Wistar ; Staphylococcus aureus/drug effects/pathogenicity/physiology ; }, abstract = {Bone infections are a significant public health burden associated with morbidity and mortality in patients. Microbial biofilm pathogens are the causative agents in chronic osteomyelitis. Research on the pathogenesis of osteomyelitis has focused on indirect bone destruction by host immune cells and cytokines secondary to microbial insult. Direct bone resorption by biofilm pathogens has not yet been seriously considered. In this study, common osteomyelitis pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Streptococcus mutans) were grown as biofilms in multiple in vitro and ex vivo experiments to analyze quantitative and qualitative aspects of bone destruction during infection. Pathogens were grown as single or mixed species biofilms on the following substrates: hydroxyapatite, rat jawbone, or polystyrene wells, and in various media. Biofilm growth was evaluated by scanning electron microscopy and pH levels were monitored over time. Histomorphologic and quantitative effects of biofilms on tested substrates were analyzed by microcomputed tomography and quantitative cultures. All tested biofilms demonstrated significant damage to bone. Scanning electron microscopy indicated that all strains formed mature biofilms within 7 days on all substrate surfaces regardless of media. Experimental conditions impacted pH levels, although this had no impact on biofilm growth or bone destruction. Presence of biofilm led to bone dissolution with a decrease of total volume by 20.17±2.93% upon microcomputed tomography analysis, which was statistically significant as compared to controls (p <0.05, ANOVA). Quantitative cultures indicated that media and substrate did not impact biofilm formation (Kruskall-Wallis test, post-hoc Dunne's test; p <0.05). Overall, these results indicate that biofilms associated with osteomyelitis have the ability to directly resorb bone. These findings should lead to a more complete understanding of the etiopathogenesis of osteomyelitis, where direct bone resorption by biofilm is considered in addition to the well-known osteoclastic and host cell destruction of bone.}, } @article {pmid28074188, year = {2016}, author = {Wang, GQ and Li, TT and Li, ZR and Zhang, LC and Zhang, LH and Han, L and Tang, PF}, title = {Effect of Negative Pressure on Proliferation, Virulence Factor Secretion, Biofilm Formation, and Virulence-Regulated Gene Expression of Pseudomonas aeruginosa In Vitro.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {7986234}, pmid = {28074188}, issn = {2314-6141}, mesh = {*Atmospheric Pressure ; Biofilms/*growth & development ; *Cell Proliferation ; *Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*pathogenicity/*physiology ; Virulence Factors/*biosynthesis ; }, abstract = {Objective. To investigate the effect of negative pressure conditions induced by NPWT on P. aeruginosa. Methods. P. aeruginosa was cultured in a Luria-Bertani medium at negative pressure of -125 mmHg for 24 h in the experimental group and at atmospheric pressure in the control group. The diameters of the colonies of P. aeruginosa were measured after 24 h. ELISA kit, orcinol method, and elastin-Congo red assay were used to quantify the virulence factors. Biofilm formation was observed by staining with Alexa Fluor® 647 conjugate of concanavalin A (Con A). Virulence-regulated genes were determined by quantitative RT-PCR. Results. As compared with the control group, growth of P. aeruginosa was inhibited by negative pressure. The colony size under negative pressure was significantly smaller in the experimental group than that in the controls (p < 0.01). Besides, reductions in the total amount of virulence factors were observed in the negative pressure group, including exotoxin A, rhamnolipid, and elastase. RT-PCR results revealed a significant inhibition in the expression level of virulence-regulated genes. Conclusion. Negative pressure could significantly inhibit the growth of P. aeruginosa. It led to a decrease in the virulence factor secretion, biofilm formation, and a reduction in the expression level of virulence-regulated genes.}, } @article {pmid28072820, year = {2017}, author = {Agulló, L and Romero-Silva, MJ and Domenech, M and Seeger, M}, title = {p-Cymene Promotes Its Catabolism through the p-Cymene and the p-Cumate Pathways, Activates a Stress Response and Reduces the Biofilm Formation in Burkholderia xenovorans LB400.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0169544}, pmid = {28072820}, issn = {1932-6203}, mesh = {Biofilms/*growth & development ; Burkholderia/*physiology ; Cymenes ; Gene Order ; Genome, Bacterial ; Genomics/methods ; *Metabolic Networks and Pathways ; Monoterpenes/*metabolism ; *Stress, Physiological ; Transcription, Genetic ; }, abstract = {p-Cymene is an aromatic terpene that is present in diverse plant species. The aims of this study were to study the p-cymene metabolism in the model aromatic-degrading bacterium Burkholderia xenovorans LB400, and its response to p-cymene. The catabolic p-cymene (cym) and p-cumate (cmt) genes are clustered on the LB400 major chromosome. B. xenovorans LB400 was able to grow on p-cymene as well as on p-cumate as a sole carbon and energy sources. LB400 growth attained higher cell concentration at stationary phase on p-cumate than on p-cymene. The transcription of the key cymAb and cmtAb genes, and p-cumate dioxygenase activity were observed in LB400 cells grown on p-cymene and on p-cumate, but not in glucose-grown cells. Diverse changes on LB400 proteome were observed in p-cymene-grown cells compared to glucose-grown cells. An increase of the molecular chaperones DnaK, GroEL and ClpB, the organic hydroperoxide resistance protein Ohr, the alkyl hydroperoxide reductase AhpC and the copper oxidase CopA during growth on p-cymene strongly suggests that the exposure to p-cymene constitutes a stress condition for strain LB400. Diverse proteins of the energy metabolism such as enolase, pyruvate kinase, aconitase AcnA, succinyl-CoA synthetase beta subunit and ATP synthase beta subunit were induced by p-cymene. Electron microscopy showed that p-cymene-grown cells exhibited fuzzy outer and inner membranes and an increased periplasm. p-Cymene induced diverse membrane and transport proteins including the p-cymene transporter CymD. Biofilm formation was reduced during growth in p-cymene in strain LB400 compared to glucose-grown cells that may be associated with a decrease of diguanylate cyclase protein levels. Overall, these results indicate active p-cymene and p-cumate catabolic pathways in B. xenovorans LB400. In addition, this study showed that p-cymene activated a stress response in strain LB400 and reduced its biofilm formation.}, } @article {pmid28071679, year = {2017}, author = {Choi, SR and Frandsen, J and Narayanasamy, P}, title = {Novel long-chain compounds with both immunomodulatory and MenA inhibitory activities against Staphylococcus aureus and its biofilm.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {40077}, pmid = {28071679}, issn = {2045-2322}, mesh = {Alkyl and Aryl Transferases/*antagonists & inhibitors ; Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Bacteria, Aerobic/drug effects/growth & development ; Biofilms/drug effects/*growth & development ; Cytokines/*metabolism ; Enzyme Inhibitors/chemical synthesis/*pharmacology ; Humans ; Immunologic Factors/chemical synthesis/*pharmacology ; Macrophages/drug effects ; Methicillin-Resistant Staphylococcus aureus/drug effects/*growth & development ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; THP-1 Cells ; Vitamin K 2/metabolism ; }, abstract = {Menaquinone (MK) biosynthesis pathway is a potential target for evaluating antimicrobials in gram-positive bacteria. Here, 1,4-dihydroxy-2-naphthoate prenyltransferase (MenA) was targeted to reduce methicillin-resistant Staphylococcus aureus (MRSA) growth. MenA inhibiting, long chain-based compounds were designed, synthesized and evaluated against MRSA and menaquinone utilizing bacteria in aerobic conditions. The results showed that these bacteria were susceptible to most of the compounds. Menaquinone (MK-4) supplementation rescued MRSA growth, suggesting these compounds inhibit MK biosynthesis. 3a and 7c exhibited promising inhibitory activities with MICs ranging 1-8 μg/mL against MRSA strains. The compounds did not facilitate small colony variant formation. These compounds also inhibited the biofilm growth by MRSA at high concentration. Compounds 3a, 6b and 7c displayed a promising extracellular bactericidal activity against MRSA at concentrations equal to and four-fold less than their respective MICs. We also observed cytokines released from THP-1 macrophages treated with compounds 3a, 6b and 7c and found decreases in TNF-α and IL-6 release and increase in IL-1β. These data provide evidence that MenA inhibitors act as TNF-α and IL-6 inhibitors, raising the potential for development and application of these compounds as potential immunomodulatory agents.}, } @article {pmid28070537, year = {2016}, author = {Azizi, O and Shahcheraghi, F and Salimizand, H and Modarresi, F and Shakibaie, MR and Mansouri, Sh and Ramazanzadeh, R and Badmasti, F and Nikbin, V}, title = {Molecular Analysis and Expression of bap Gene in Biofilm-Forming Multi-Drug-Resistant Acinetobacter baumannii.}, journal = {Reports of biochemistry & molecular biology}, volume = {5}, number = {1}, pages = {62-72}, pmid = {28070537}, issn = {2322-3480}, abstract = {BACKGROUND: Acinetobacter baumannii is commonly resistant to nearly all antibiotics due to presence of antibiotic resistance genes and biofilm formation. In this study we determined the presence of certain antibiotic-resistance genes associated with biofilm production and the influence of low iron concentration on expression of the biofilm-associated protein gene (bap) in development of biofilm among multi-drug-resistant A. baumannii (MDRAB).

METHODS: Sixty-five MDRAB isolates from clinical samples were collected. Molecular typing was carried out by random amplified polymorphism DNA polymerase chain reaction (RAPD-PCR). Biofilm formation was assayed by the microtiter method.

RESULTS: The sequence of bap was determined and deposited in the GenBank database (accession no. KR080550.1). Expression of bap in the presence of low iron was analyzed by relative quantitative real time PCR (rqRT-PCR). Nearly half of the isolates belonged to RAPD-types A and B remaining were either small clusters or singleton. The results of biofilm formation revealed that 23 (35.4%), 18 (27.7%), 13 (20%), and 11 (16.9%) of the isolates had strong, moderate, weak, and no biofilm activities, respectively. ompA and csuE genes were detected in all, while bap and blaPER-1 were detected in 43 (66%) and 42 (64%) of the isolates that showed strong and moderate biofilm activities (p ≤ 0.05), respectively. Analysis of bap expression by rqRT-PCR revealed five isolates with four-fold bap overexpression in the presence of low iron concentration (20 µM).

CONCLUSION: The results suggest that bap overexpression may influence biofilm formation in presence of low iron concentration.}, } @article {pmid28070515, year = {2016}, author = {Voronina, OL and Kunda, MS and Ryzhova, NN and Aksenova, EI and Semenov, AN and Romanova, YM and Gintsburg, AL}, title = {Burkholderia contaminans Biofilm Regulating Operon and Its Distribution in Bacterial Genomes.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {6560534}, pmid = {28070515}, issn = {2314-6141}, mesh = {Achromobacter ; *Biofilms ; Burkholderia Infections/microbiology ; Burkholderia cepacia complex/*genetics/*metabolism ; Computational Biology ; Cystic Fibrosis/complications/microbiology ; DNA, Ribosomal/genetics ; Gene Expression Regulation, Bacterial ; Gene Transfer Techniques ; Genome ; *Genome, Bacterial ; Histidine Kinase/genetics ; Humans ; Lung Diseases/*microbiology ; Mutagenesis ; *Operon ; Phylogeny ; Sequence Analysis, DNA ; Signal Transduction ; Transcription, Genetic ; }, abstract = {Biofilm formation by Burkholderia spp. is a principal cause of lung chronic infections in cystic fibrosis patients. A "lacking biofilm production" (LBP) strain B. contaminans GIMC4587:Bct370-19 has been obtained by insertion modification of clinical strain with plasposon mutagenesis. It has an interrupted transcriptional response regulator (RR) gene. The focus of our investigation was a two-component signal transduction system determination, including this RR. B. contaminans clinical and LBP strains were analyzed by whole genome sequencing and bioinformatics resources. A four-component operon (BiofilmReg) has a key role in biofilm formation. The relative location (i.e., by being separated by another gene) of RR and histidine kinase genes is unique in BiofilmReg. Orthologs were found in other members of the Burkholderiales order. Phylogenetic analysis of strains containing BiofilmReg operons demonstrated evidence for earlier inheritance of a three-component operon. During further evolution one lineage acquired a fourth gene, whereas others lost the third component of the operon. Mutations in sensor domains have created biodiversity which is advantageous for adaptation to various ecological niches. Different species Burkholderia and Achromobacter strains all demonstrated similar BiofilmReg operon structure. Therefore, there may be an opportunity to develop a common drug which is effective for treating all these causative agents.}, } @article {pmid28068590, year = {2017}, author = {Marin-Menguiano, M and Romero-Sanchez, S and Barrales, RR and Ibeas, JI}, title = {Population analysis of biofilm yeasts during fino sherry wine aging in the Montilla-Moriles D.O. region.}, journal = {International journal of food microbiology}, volume = {244}, number = {}, pages = {67-73}, doi = {10.1016/j.ijfoodmicro.2016.12.019}, pmid = {28068590}, issn = {1879-3460}, mesh = {Acetaldehyde/*analysis ; Biofilms/*growth & development ; DNA, Intergenic/genetics ; Fermentation/*physiology ; Food Microbiology ; Food Storage/methods ; Mycological Typing Techniques/*methods ; Polymorphism, Restriction Fragment Length ; Saccharomyces cerevisiae/*genetics/isolation & purification/*metabolism ; Spain ; Wine/analysis/*microbiology ; }, abstract = {Fino is the most popular sherry wine produced in southern Spain. Fino is matured by biological aging under a yeast biofilm constituted of Saccharomyces cerevisiae yeasts. Although different S. cerevisiae strains can be identified in such biofilms, their diversity and contribution to wine character have been poorly studied. In this work, we analyse the flor yeast population in five different wineries from the Montilla-Moriles D.O. (Denominación de Origen) in southern Spain. Yeasts present in wines of different ages were identified using two different culture-dependent molecular techniques. From 2000 individual yeast isolates, five different strains were identified with one of them dominating in four out of the five wineries analysed, and representing 76% of all the yeast isolates collected. Surprisingly, this strain is similar to the predominant strain isolated twenty years ago in Jerez D.O. wines, suggesting that this yeast is particularly able to adapt to such a stressful environment. Fino wine produced with pure cultures of three of the isolated strains resulted in different levels of acetaldehyde. Because acetaldehyde levels are a distinctive characteristic of fino wines and an indicator of fino aging, the use of molecular techniques for yeast identification and management of yeast populations may be of interest for fino wine producers looking to control one of the main features of this wine.}, } @article {pmid28068182, year = {2017}, author = {Decker, EM and Bartha, V and von Ohle, C}, title = {Improvement of Antibacterial Efficacy Through Synergistic Effect in Photodynamic Therapy Based on Thiazinium Chromophores Against Planktonic and Biofilm-Associated Periodontopathogens.}, journal = {Photomedicine and laser surgery}, volume = {35}, number = {4}, pages = {195-205}, doi = {10.1089/pho.2016.4152}, pmid = {28068182}, issn = {1557-8550}, mesh = {Analysis of Variance ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/radiation effects ; Colony Count, Microbial ; Confidence Intervals ; Drug Synergism ; Enterococcus faecalis/*drug effects/radiation effects ; Humans ; In Vitro Techniques ; Methylene Blue/*pharmacology ; Microbial Viability ; Periodontium/microbiology ; Photochemotherapy/*methods ; Plankton/*drug effects/radiation effects ; Reference Values ; Tolonium Chloride/*pharmacology ; Tooth Extraction ; }, abstract = {OBJECTIVE: Aim of the study was to improve the antibacterial efficacy of toluidine blue (TBO)/methylene blue (MB)-mediated photodynamic systems with light-emitting diode (LED) or laser irradiation administered to planktonic and biofilm-associated periodontopathogens.

BACKGROUND DATA: Antibacterial photodynamic therapy (PDT) is a common, noninvasive adjunctive clinical method to inactivate microorganisms. So far, the disadvantage of this method has been its limited effectiveness in eliminating pathogens.

METHODS: An anaerobic cocktail consisting of six representative periodontal pathogens was prepared as initial culture for planktonic samples and biofilms grown on human tooth slides. Both types of microbial samples were exposed to three commercial photodynamic systems (PDT1: TBO, 630 nm LED, PDT2: TBO, 635 nm laser, PDT3: MB, 665 nm laser) in conventional and a new modified approach (PDT[plus]) based on the use of an oxygen supplement (photosensitizer+hydrogen peroxide). The microbial viability was characterized by bacterial growth [colony forming units (CFU)], total bacterial cell counts, and microbial vitality. Statistical data analysis was performed using 95% confidence intervals (ANOVA) and post hoc Tukey's test (p < 0.05).

RESULTS: The modified PDT[plus] showed the highest statistically significant synergistic antimicrobial activity for TBO-based systems evidenced by a CFU reduction of 9 log10 units to 0 for planktonic pathogens and a 4 log10 CFU reduction for biofilm bacteria. The MB-based PDT[plus] was superior mainly against biofilm pathogens. By comparison, the default TBO-based PDT achieved colony growth reductions of 2 and 1 log10 units concerning planktonic and biofilm cells.

CONCLUSIONS: Compared to conventional PDT, PDT[plus] showed superior antibacterial efficacy based on its synergistic effect, promising vast application possibilities.}, } @article {pmid28067286, year = {2017}, author = {Yang, H and Zhang, H and Wang, J and Yu, J and Wei, H}, title = {A novel chimeric lysin with robust antibacterial activity against planktonic and biofilm methicillin-resistant Staphylococcus aureus.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {40182}, pmid = {28067286}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms ; Hydrolases/chemistry/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Molecular Conformation ; }, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most threatening pathogens due to its multi-drug resistance (MDR) and strong biofilm-forming capacity. Here, we described the screening of a novel chimeolysin (ClyF) that was active against planktonic and biofilm MRSA. Biochemical tests showed that ClyF was active against all S. aureus clinical isolates tested under planktonic and biofilm conditions. Structure analysis revealed that ClyF has an enhanced thermostability and pH tolerance than its parental lysin Pc by forming a hydrophobic cleft in the catalytic domain and an Ig-like structure in the cell-wall binding domain. A single intraperitoneally or topically administration of ClyF showed good MRSA removing efficacy in mouse models of bacteremia and burn wound infection, respectively. Our data collectively demonstrated that ClyF has good bactericidal activity against planktonic and biofilm MRSA both in vitro and in vivo, and therefore represents a useful antibacterial to combat MDR S. aureus.}, } @article {pmid28066389, year = {2016}, author = {Reen, FJ and Phelan, JP and Woods, DF and Shanahan, R and Cano, R and Clarke, S and McGlacken, GP and O'Gara, F}, title = {Harnessing Bacterial Signals for Suppression of Biofilm Formation in the Nosocomial Fungal Pathogen Aspergillus fumigatus.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {2074}, pmid = {28066389}, issn = {1664-302X}, abstract = {Faced with the continued emergence of antibiotic resistance to all known classes of antibiotics, a paradigm shift in approaches toward antifungal therapeutics is required. Well characterized in a broad spectrum of bacterial and fungal pathogens, biofilms are a key factor in limiting the effectiveness of conventional antibiotics. Therefore, therapeutics such as small molecules that prevent or disrupt biofilm formation would render pathogens susceptible to clearance by existing drugs. This is the first report describing the effect of the Pseudomonas aeruginosa alkylhydroxyquinolone interkingdom signal molecules 2-heptyl-3-hydroxy-4-quinolone and 2-heptyl-4-quinolone on biofilm formation in the important fungal pathogen Aspergillus fumigatus. Decoration of the anthranilate ring on the quinolone framework resulted in significant changes in the capacity of these chemical messages to suppress biofilm formation. Addition of methoxy or methyl groups at the C5-C7 positions led to retention of anti-biofilm activity, in some cases dependent on the alkyl chain length at position C2. In contrast, halogenation at either the C3 or C6 positions led to loss of activity, with one notable exception. Microscopic staining provided key insights into the structural impact of the parent and modified molecules, identifying lead compounds for further development.}, } @article {pmid28065820, year = {2017}, author = {Vasavi, HS and Sudeep, HV and Lingaraju, HB and Shyam Prasad, K}, title = {Bioavailability-enhanced Resveramax™ modulates quorum sensing and inhibits biofilm formation in Pseudomonas aeruginosa PAO1.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {64-71}, doi = {10.1016/j.micpath.2017.01.015}, pmid = {28065820}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/pharmacokinetics/*pharmacology ; Bacterial Proteins/chemistry/metabolism ; Biofilms/*drug effects ; Biological Availability ; Biosensing Techniques ; Drug Synergism ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Conformation ; Protein Binding ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects/*physiology ; Quorum Sensing/*drug effects ; Resveratrol ; Stilbenes/chemistry/pharmacokinetics/*pharmacology ; Trans-Activators/chemistry/metabolism ; }, abstract = {Quorum sensing (QS), a cell-to-cell communication mechanism present in many bacterial species plays a key role in regulating the virulence factor and biofilm formation in many pathogens, which causes severe public health risk. Therefore, interfering with QS mechanism offers an attractive strategy to combat bacterial infections. In the present study, anti-QS activity of a novel resveratrol formulation, Resveramax™, was detected using Chromobacterium violaceum biosensor bioassay and the effect of Resveramax on QS-regulated phenotypes in Pseudomonas aeruginosa PAO1 was assessed by standard protocols. Molecular docking analysis of resveratrol, the major active constituent of Resveramax, with LasR receptor protein was performed to evidence the QS-inhibitory potential of Resveramax. Results showed that Resveramax specifically inhibited the QS-mediated violacein pigment production in C. violaceum; pyocyanin production, proteolytic activity, swarming motility and biofilm formation in P. aeruginosa PAO1 in a concentration-dependent manner. Biofilms treated with Resveramax showed increased susceptibility to antibiotics when compared with the antibiotic treatment alone. Molecular docking analysis proved that resveratrol binds more rigidly with LasR receptor protein with docking score of -8.55 kJ/mol. These findings suggest that Resveramax could be used as novel QS-based antibacterial/anti-biofilm agent for the management of bacterial infections.}, } @article {pmid28065625, year = {2017}, author = {Morris, MR and Bergum, C and Jackson, N and Markel, DC}, title = {Decreased Bacterial Adherence, Biofilm Formation, and Tissue Reactivity of Barbed Monofilament Suture in an In Vivo Contaminated Wound Model.}, journal = {The Journal of arthroplasty}, volume = {32}, number = {4}, pages = {1272-1279}, doi = {10.1016/j.arth.2016.11.010}, pmid = {28065625}, issn = {1532-8406}, mesh = {Animals ; *Bacterial Adhesion ; Biofilms ; Female ; Interleukin-1/metabolism ; Mice, Inbred BALB C ; Microscopy, Electron, Scanning ; Staphylococcal Infections/metabolism/microbiology/*prevention & control ; Staphylococcus aureus ; Surgical Wound Infection/metabolism/*prevention & control ; Suture Techniques ; *Sutures ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {BACKGROUND: Monofilament and barbed monofilament sutures have been shown in in vitro models to have less bacterial adherence than braided suture. This study evaluates bacterial adherence to suture materials and tissue reactivity with an in vivo contaminated wound mouse model.

METHODS: Staphylococcus aureus was used to create an in vivo contaminated wound model at 2 amounts (10[6] colony-forming units [CFU] and 10[8] CFU) using a mouse air pouch. Three types of commonly used absorbable suture were evaluated: braided, monofilament, and barbed monofilament. Bacterial suture adherence was evaluated with suture culture, a photon-capturing camera system, and scanning electron microscopy. Tissue reactivity was assessed through histology and protein expression.

RESULTS: The braided suture group with the high amount of S aureus exhibited frank purulence and air pouch hypertrophy in all 8 mice. A significant difference was found between suture groups inoculated with 10[8] CFU (P < .05) as measured by bacterial culture concentration using the optical density method. The braided suture hosted more bacteria than either monofilament (P < .005) or barbed monofilament suture (P < .005). No difference was appreciated between the monofilament and barbed monofilament groups. Kruskal-Wallis test demonstrated a significant difference between groups in regard to levels of tumor necrosis factor-α (P < .05) and interleukin-1 (P < .05).

CONCLUSION: Our in vivo contaminated wound model demonstrated that barbed monofilament suture performed similarly to monofilament suture and better than braided suture in terms of bacterial adherence, biofilm formation, and tissue reactivity.}, } @article {pmid28063305, year = {2017}, author = {Song, YG and Lee, SH}, title = {Inhibitory effects of Lactobacillus rhamnosus and Lactobacillus casei on Candida biofilm of denture surface.}, journal = {Archives of oral biology}, volume = {76}, number = {}, pages = {1-6}, doi = {10.1016/j.archoralbio.2016.12.014}, pmid = {28063305}, issn = {1879-1506}, mesh = {*Antibiosis ; Biofilms/*drug effects ; Candida/*drug effects ; Cell Adhesion ; Dental Materials ; Denture Bases/microbiology ; Dentures/*microbiology ; Lacticaseibacillus casei/*physiology ; Lacticaseibacillus rhamnosus/*physiology ; Microbial Interactions ; Probiotics/*pharmacology ; Surface Properties ; }, abstract = {OBJECTIVE: Candida albicans biofilm is associated with denture-related stomatitis and oral candidiasis of elderly. Probiotics are beneficial bacteria and have antibacterial activity against pathogenic bacteria. The purpose of this study was to investigate the antifungal activity of various probiotics against C. albicans and the inhibitory effects of probiotics on Candida biofilm on the denture surface.

DESIGN: The spent culture media of various probiotics were investigated the antifungal efficacy against C. albicans. Candida biofilm was formed on a denture base resin and was then treated with Lactobacillus rhamnosus and Lactobacillus casei. Also, the biofilms of L. rhamnosus and L. casei were formed and were sequentially treated with C. albicans. Colony-forming units of C. albicans on the denture surface were counted after spreading on agar plate. The denture base resin was treated with the spent culture media for 30days, after which the denture surface roughness was analyzed with an atomic force microscope.

RESULTS: L. rhamnosus and L. casei exhibited stronger antifungal activity than other probiotics. The spent culture medium of L. rhamnosus and L. casei exhibited the antifungal activity against blastoconidia and biofilm of C. albicans. L. rhamnosus and L. casei showed the antifungal activity against Candida biofilm, and the biofilm of L. rhamnosus and L. casei inhibited formation of Candida biofilm on denture surface. Neither of the probiotics affected the surface roughness of the denture base resin.

CONCLUSIONS: L. rhamnosus and L. casei may be the ideal probiotics for the prevention and treatment of denture-related stomatitis.}, } @article {pmid28063237, year = {2017}, author = {Hughes, G and Webber, MA}, title = {Novel approaches to the treatment of bacterial biofilm infections.}, journal = {British journal of pharmacology}, volume = {174}, number = {14}, pages = {2237-2246}, pmid = {28063237}, issn = {1476-5381}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Humans ; }, abstract = {UNLABELLED: Bacterial infection remains a major challenge to healthcare and is responsible for significant morbidity and mortality. This situation is becoming complicated by an increasingly ageing and susceptible population and large numbers of bacterial isolates, which have developed resistance to antibiotics. Bacteria that form biofilms and colonize or infect medical devices or wounds are particularly hard to treat as biofilms are inherently highly antibiotic resistant. Most infections have a component where bacteria exist as a biofilm and as a result, prevention or treatment of biofilm-associated infections is highly important. A number of novel strategies to kill biofilms have been in development; these include the use of weak organic acids, photo irradiation and the application of bacteriophage. All have promise and are able to effectively kill biofilms in model systems, but for each there are still unanswered questions. This review summarizes the main features of biofilm infections, each of these novel approaches and the evidence that is still lacking before these potential treatments can be incorporated into clinical usage.

LINKED ARTICLES: This article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.14/issuetoc.}, } @article {pmid28062459, year = {2017}, author = {van der Kooij, D and Bakker, GL and Italiaander, R and Veenendaal, HR and Wullings, BA}, title = {Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {5}, pages = {}, pmid = {28062459}, issn = {1098-5336}, mesh = {Amoeba/growth & development ; Bacteria/growth & development ; Bacterial Adhesion ; Biofilms/*growth & development ; Biomass ; Colony Count, Microbial ; Copper ; Disinfectants ; Drinking Water/*microbiology ; Fresh Water/chemistry/*microbiology ; Glass ; Hot Temperature ; Legionella pneumophila/*growth & development/isolation & purification/physiology ; Legionnaires' Disease/prevention & control ; Nickel ; Surface Properties ; *Water Microbiology ; *Water Supply ; }, abstract = {Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm[-2]) exposed to treated aerobic groundwater (0.3 mg C liter[-1]; 1 μg assimilable organic carbon [AOC] liter[-1]) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm[-2]) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm[-2] in the biofilms on glass (1,055 ± 225 pg ATP cm[-2]) and CPVC (2,755 ± 460 pg ATP cm[-2]) exposed to treated anaerobic groundwater (7.9 mg C liter[-1]; 10 μg AOC liter[-1]). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis This amoeba was rarely detected at biofilm concentrations of <100 pg ATP cm[-2] A threshold concentration of approximately 50 pg ATP cm[-2] (TCC = 1 × 10[6] to 2 × 10[6] cells cm[-2]) was derived for growth of L. pneumophila in biofilms.IMPORTANCELegionella pneumophila is the etiologic agent in more than 10,000 cases of Legionnaires' disease that are reported annually worldwide and in most of the drinking water-associated disease outbreaks reported in the United States. The organism proliferates in biofilms on surfaces exposed to warm water in engineered freshwater installations. An investigation with a test system supplied with different types of warm drinking water without disinfectant under controlled hydraulic conditions showed that treated aerobic groundwater (0.3 mg liter[-1] of organic carbon) induced a low biofilm concentration that supported no or very limited growth of L. pneumophila Elevated biofilm concentrations and L. pneumophila colony counts were observed on surfaces exposed to two types of extensively treated groundwater, containing 1.8 and 7.9 mg C liter[-1] and complying with the microbial water quality criteria during distribution. Control measures in warm tap water installations are therefore essential for preventing growth of L. pneumophila.}, } @article {pmid28062294, year = {2017}, author = {Valadbeigi, H and Sadeghifard, N and Salehi, MB}, title = {Assessment of biofilm formation in Pseudomonas aeruginosa by antisense mazE-PNA.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {28-31}, doi = {10.1016/j.micpath.2017.01.009}, pmid = {28062294}, issn = {1096-1208}, mesh = {Antitoxins/genetics/*immunology ; Bacterial Proteins/genetics/*immunology ; *Biofilms ; Gene Expression ; Humans ; Immune Sera/*immunology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*genetics/*immunology ; Quantitative Trait Loci ; Stress, Physiological ; }, abstract = {The hallmark patogenicity in Pseudomonas aeruginosa (P. aeruginosa) is biofilm formation that is not easy to eradicate, because it has variety mechanisms for antibiotic resistance. In addition, toxin-antitoxin (TA) system may play role in biofilm formation. The current study aimed to evaluate the role of TA loci in biofilm formation. Therefore, 18 P. aeruginosa clinical isolates were collected and evaluated for specific biofilm and TA genes. The analysis by RT-qPCR demonstrated that expression of mazE antitoxin in biofilm formation was increase. On the other hand, mazE antitoxin TA system was used as target for antisense PNA. mazE-PNA was able to influence in biofilm formation and was inhibit at 5,10 and 15 μM concentrations biofilm formation in P. aeruginosa. Therefore, it could be highlighted target for anti-biofilm target to eradicate P. aeruginosa biofilm producer.}, } @article {pmid28062292, year = {2017}, author = {Miladi, H and Zmantar, T and Kouidhi, B and Chaabouni, Y and Mahdouani, K and Bakhrouf, A and Chaieb, K}, title = {Use of carvacrol, thymol, and eugenol for biofilm eradication and resistance modifying susceptibility of Salmonella enterica serovar Typhimurium strains to nalidixic acid.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {56-63}, doi = {10.1016/j.micpath.2017.01.012}, pmid = {28062292}, issn = {1096-1208}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cymenes ; Dose-Response Relationship, Drug ; *Drug Resistance, Bacterial ; Drug Synergism ; Eugenol/*pharmacology ; Microbial Sensitivity Tests ; Monoterpenes/*pharmacology ; Nalidixic Acid/*pharmacology ; Oils, Volatile/pharmacology ; Salmonella typhimurium/*drug effects/ultrastructure ; Thymol/*pharmacology ; }, abstract = {The Aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (CAR), thymol (TH) and eugenol (EUG), alone or in combination with nalidixic acid (NA) against twelve Salmonella Typhimurium strains. The minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (BEC50) of the tested compounds (CAR, TH and EUG) and their combinations with NA were evaluated. In order to assess whether these bacteria had active efflux pumps, ethidium bromide (EtBr) accumulation assays was achieved using spectrophotometric accumulation assays. Moreover, scanning electron microscopy was used to visualize the bacterial biofilm formation on stainless steel surfaces after exposed to NA, CAR, TH and EUG alone and in combination. TH was the most effective essential oil, with the lowest MICs values ranging from 32 to 128 μg/mL followed by EUG and CAR. In addition, the combination of NA with the different compounds enhances antibiotic susceptibility of the tested bacterial strains. These results were confirmed by EtBr accumulation assays. A pronounced effect in decreasing biofilm mass was also noticed. Moreover, SEM revealed that bacterial membrane was disrupted and a complete loss of membrane integrity was also evident. The combination of natural compounds with antibiotic enhances bacterial susceptibility to NA. This combination ameliorates eradication of biofilm formed by S. Typhimurium on polystyrene microtitre plates. Additionally, this synergy induces an alteration of the bacterial cell surface visualized by SEM.}, } @article {pmid28062286, year = {2017}, author = {Ji, Y and Li, W and Zhang, Y and Chen, L and Zhang, Y and Zheng, X and Huang, X and Ni, B}, title = {QseB mediates biofilm formation and invasion in Salmonella enterica serovar Typhi.}, journal = {Microbial pathogenesis}, volume = {104}, number = {}, pages = {6-11}, doi = {10.1016/j.micpath.2017.01.010}, pmid = {28062286}, issn = {1096-1208}, mesh = {Bacterial Proteins/*genetics ; *Biofilms ; Epithelial Cells/microbiology ; Gene Expression ; Gene Expression Regulation, Bacterial ; HeLa Cells ; Humans ; Phenotype ; Salmonella typhi/*genetics/*growth & development/pathogenicity ; Virulence/genetics ; }, abstract = {QseB is a response regulator of the QseBC two-component system (TCS) which is associated with quorum sensing and functions as a global regulator of flagella, biofilm formation, and virulence. The function of QseB and its interaction with QseC has been the subject of study in some organisms, however, little work was done in Salmonella enterica serovar Typhi (S. Typhi). The objective of this study was to investigate the effect of QseB on biofilm formation and virulence in S. Typhi. It showed that the biofilm formation ability of qseC mutant was limited as compared to the wild type strain. We also show overexpression of qseB was in a qseC mutant. Interestingly, deletion of qseB in a qseC mutant restored a wild type phenotype. These results suggested that QseB may account for the impaired biofilm formation in the absence of QseC. Furthermore, deletion of qseB in wild type cells decreased biofilm formation, whereas overexpression of qseB in wild type cells increased biofilm formation. Quantitative real-time PCR also revealed the up-regulation of some fimbria-associated genes in a qseB overexpression strain. These results indicate that QseB may enhance biofilm formation in the presence of QseC. Taken together, we hypothesize that QseB has dual regulatory functions which are dependent upon its cognate sensor. Additionally, invasion of HeLa cells was enhanced in qseB mutant but attenuated in a qseC mutant compared with wild-type. The β-galactosidase activity of invF::lacZ was increased in qseB mutant but decreased in qseC mutant which was consistent with invasion results. In conclusion, QseB may have dual regulatory functions concerning biofilm formation and plays a negative role in virulence of S. Typhi.}, } @article {pmid28062284, year = {2017}, author = {Odeyemi, OA and Ahmad, A}, title = {Population dynamics, antibiotics resistance and biofilm formation of Aeromonas and Vibrio species isolated from aquatic sources in Northern Malaysia.}, journal = {Microbial pathogenesis}, volume = {103}, number = {}, pages = {178-185}, doi = {10.1016/j.micpath.2017.01.007}, pmid = {28062284}, issn = {1096-1208}, mesh = {Aeromonas/*classification/*drug effects/genetics/isolation & purification ; *Biofilms ; *Drug Resistance, Bacterial ; Geography ; Geologic Sediments/microbiology ; Gram-Negative Bacterial Infections/*epidemiology/*microbiology ; Humans ; Malaysia/epidemiology ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/microbiology ; Vibrio/*classification/*drug effects/genetics/isolation & purification ; Vibrio Infections/epidemiology/microbiology ; Water Microbiology ; }, abstract = {This study aimed to compare population dynamics, antibiotic resistance and biofilm formation of Aeromonas and Vibrio species from seawater and sediment collected from Northern Malaysia. Isolates with different colony morphology were characterized using both biochemical and molecular methods before testing for antibiotic resistance and biofilm formation. Results obtained from this study showed that in Kedah, the population of Aeromonas isolated from sediment was highest in Pantai Merdeka (8.22 log CFU/ml), Pulau Bunting recorded the highest population of Aeromonas from sediment (8.43 log CFU/g). It was observed that Vibrio species isolated from seawater and sediment were highest in Kuala Sanglang (9.21 log CFU/ml). In Kuala Perlis, the population of Aeromonas isolated from seawater was highest in Jeti (7.94 log CFU/ml). Highest population of Aeromonas from sediment was recorded in Kampong Tanah Baru (7.99 log CFU/g). It was observed that Vibrio species isolated from seawater was highest in Padang Benta (8.42 log CFU/g) while Jeti Kuala Perlis had highest population of Vibrio isolated from sediment. It was observed that location does not influence population of Aeromonas. The results of the independent t - test revealed that there was no significant relationship between location and population of Vibrio (df = 10, t = 1.144, p > 0.05). The occurrence of biofilm formation and prevalence of antibiotic resistant Aeromonas and Vibrio species in seawater and sediment pose danger to human and aquatic animals' health.}, } @article {pmid28062182, year = {2017}, author = {Roussel, L and Rousseau, S}, title = {Exposure of airway epithelial cells to Pseudomonas aeruginosa biofilm-derived quorum sensing molecules decrease the activity of the anti-oxidant response element bound by NRF2.}, journal = {Biochemical and biophysical research communications}, volume = {483}, number = {2}, pages = {829-833}, doi = {10.1016/j.bbrc.2017.01.009}, pmid = {28062182}, issn = {1090-2104}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; *Antioxidant Response Elements ; Biofilms ; Cell Line ; Cystic Fibrosis/microbiology ; Epithelial Cells/metabolism/microbiology ; Gene Expression Regulation ; Heme Oxygenase-1/genetics ; Homoserine/analogs & derivatives/metabolism ; Humans ; Interleukin-8/genetics ; Lung/metabolism/microbiology/pathology ; NAD(P)H Dehydrogenase (Quinone)/genetics ; NF-E2-Related Factor 2/genetics/*metabolism ; Pseudomonas Infections/metabolism/microbiology/pathology ; Pseudomonas aeruginosa/metabolism/*pathogenicity ; Quorum Sensing/*physiology ; }, abstract = {Chronic bacterial infections in cystic fibrosis lung disease are often characterized by Pseudomonas aeruginosa biofilms that are regulated by bacterial intercellular signals termed quorum sensing (QS), such as N-(3-oxododecanoyl)-l-homoserine lactone (3OC12-HSL). This study reports that biofilm-derived exoproducts decrease the transcriptional activity of the anti-oxidant response element in bronchial epithelial cells. In a live co-culture assay of BEAS-2B cells and P. aeruginosa biofilm, the QS molecule 3OC12-HSL was an important but not sole contributor to the inhibition of basal NRF2 luciferase reporter activity. Moreover, biofilm-derived exoproducts and 3OC12-HSL decrease the expression of endogenous antioxidant response element-regulated genes hemeoxygenase-1 (HO-1) and NAD(P)H Quinone Dehydrogenase-1 (NQO-1) while they increase IL-8 expression. As previously reported, IL-8 expression is partially dependent on p38 MAPK activity, but the inhibitory effect of biofilm QS molecules on HO-1 and NQO-1 expression occurs independently of this protein kinase. Finally, the transfection of CFTRdelF508 but not its wild type counterpart decreases basal, planktonic PsaDM and sulforaphane-driven NRF2 luciferase reporter activity in BEAS-2B cells. Therefore, the presence of quorum sensing molecules derived from bacterial biofilms lowers the transcriptional activity of the anti-oxidant response element, which may contribute to the establishment of chronic bacterial infections, especially in the presence of mutated CFTR. Increasing NRF2 activity may thus be a promising strategy to potentiate anti-biofilm activity in cystic fibrosis lung disease.}, } @article {pmid28062003, year = {2017}, author = {Wang, Y and Yi, L and Zhang, F and Qiu, X and Tan, L and Yu, S and Cheng, X and Ding, C}, title = {Identification of genes involved in Mycoplasma gallisepticum biofilm formation using mini-Tn4001-SGM transposon mutagenesis.}, journal = {Veterinary microbiology}, volume = {198}, number = {}, pages = {17-22}, doi = {10.1016/j.vetmic.2016.11.021}, pmid = {28062003}, issn = {1873-2542}, mesh = {*Biofilms ; DNA Transposable Elements/genetics ; Genes, Bacterial/*genetics ; Genetic Vectors/genetics ; *Mutagenesis, Insertional ; Mutation ; Mycoplasma gallisepticum/genetics/*physiology ; Plasmids/genetics ; }, abstract = {Mycoplasma gallisepticum (MG) is an important pathogen that can cause chronic respiratory disease in chickens and infectious sinusitis in turkeys. MG has the ability to form biofilms. The molecular mechanisms underlying MG biofilm formation are complex and poorly understood. To better understand the mechanisms involved in biofilm formation, mini-Tn4001-SGM, a novel transposon vector containing the gentamicin gene was constructed and electroporated into MG strain Rlow. Of the 738 mutants obtained, 12 had significantly reduced capacity to form biofilms in a polystyrene microtiter-plate biofilm assay. Ten different genes were identified as disrupted in these mutants using genomic walking from the transposon insertion sites and Southern bolt hybridization with a transposon-based probe. Four genes were associated with cellular processes, especially synthesis of extracellular polysaccharide and several lipoproteins encoded. Other genes were associated with translation, metabolism and gene regulation, and one had unknown function. Seven genes identified in this study have been previously associated with biofilm formation in MG or other bacterial species. The other three have not been previously reported to play a role in biofilm formation in MG. In conclusion, a new transposon vector was shown to be a powerful tool for future studies of MG pathogenesis. This study adds to our understanding of the molecular mechanisms involved in MG biofilm formation and may shed light on the persistence of MG infections.}, } @article {pmid28061939, year = {2016}, author = {Sarkar, S and Mazumder, D}, title = {Development of a Simplified Model for Completely Mixed Biofilm Reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {88}, number = {12}, pages = {2260-2267}, doi = {10.2175/106143016X14733681695924}, pmid = {28061939}, issn = {1061-4303}, mesh = {Algorithms ; *Biofilms ; *Bioreactors ; *Models, Theoretical ; Software ; Waste Disposal, Fluid/methods ; }, abstract = {A simplified model for the completely mixed biofilm process formulated correlations between entering and exiting substrate concentrations, average substrate flux in the biofilm and effective biofilm thickness. The model essentially considered the substrate mass transport into the biofilm as per Fick's second law and steady state substrate as well as biomass balance for biofilm. The numerical solution of the biofilm model involved evaluation of the average flux along with exiting substrate concentration and application of the Runge-Kutta method for determining the effective biofilm thickness. Accordingly, two computer programs were developed for the sake of quick solution. The solution model was successfully applied in several cases with varying range of representative input variables. The model performance was compared with available existing methods and validated with the experimental results. It was found as an easy, accurate and fast method that can be used for process design.}, } @article {pmid28061932, year = {2016}, author = {Patel, BP and Kumar, A}, title = {Biodegradation of 2,4-dichlorophenol in Packed-Bed Biofilm Reactor: Effect of Hydraulic Retention Time, Biogenic Substrate, and Loading Rate.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {88}, number = {12}, pages = {2191-2197}, doi = {10.2175/106143016X14733681695726}, pmid = {28061932}, issn = {1061-4303}, mesh = {Bacteria/drug effects ; Bacterial Physiological Phenomena ; *Biodegradation, Environmental ; Biofilms/*growth & development ; *Bioreactors ; Chlorophenols/chemistry/*metabolism ; Microscopy, Electron, Scanning ; Peptones ; Time Factors ; Waste Disposal, Fluid ; Water Pollutants, Chemical/chemistry/*metabolism ; }, abstract = {The removal of 2,4-dichlorophenol (2,4-DCP) by a pure culture of Bacillus endophyticus strain immobilized on ceramic balls was studied in a packed bed biofilm reactor (PBBR). The biodegradation of 2,4-DCP was studied in fed-batch and continuous mode and the effect of different parameters such as hydraulic retention time (HRT), biogenetic substrate concentration, and loading rate on the removal of 2,4-DCP were evaluated. Field emission scanning electron microscope (FESEM) results established the biofilm formation on the ceramic beads. The maximum volumetric removal rate found to be 127.2 mg/L·d at loading rate of 172.8 mg/L·d with 73.6% degradation (12.5 hours of HRT, 90 mg/L of 2,4-DCP, 0.2 g/L of peptone). The bioreactor showed more than 98% removal of 2,4-DCP at loading rate of 115.2 mg/L·d at 12.5 hours of HRT and 0.2 g/L of peptone. Effect of peptone showed that lower peptone concentration increases the removal efficiency; however, some peptone is necessary to maintain the 2,4-DCP removal efficiency.}, } @article {pmid28061393, year = {2017}, author = {Demeter, MA and Lemire, JA and Mercer, SM and Turner, RJ}, title = {Screening selectively harnessed environmental microbial communities for biodegradation of polycyclic aromatic hydrocarbons in moving bed biofilm reactors.}, journal = {Bioresource technology}, volume = {228}, number = {}, pages = {116-124}, doi = {10.1016/j.biortech.2016.12.086}, pmid = {28061393}, issn = {1873-2976}, mesh = {Bacteria/genetics/metabolism ; Biodegradation, Environmental ; *Biofilms/growth & development ; Biological Availability ; *Bioreactors ; *Environmental Microbiology ; Genes, Bacterial ; Polycyclic Aromatic Hydrocarbons/*metabolism ; Polymerase Chain Reaction ; }, abstract = {Bacteria are often found tolerating polluted environments. Such bacteria may be exploited to bioremediate contaminants in controlled ex situ reactor systems. One potential strategic goal of such systems is to harness microbes directly from the environment such that they exhibit the capacity to markedly degrade organic pollutants of interest. Here, the use of biofilm cultivation techniques to inoculate and activate moving bed biofilm reactor (MBBR) systems for the degradation of polycyclic aromatic hydrocarbons (PAHs) was explored. Biofilms were cultivated from 4 different hydrocarbon contaminated sites using a minimal medium spiked with the 16 EPA identified PAHs. Overall, all 4 inoculant sources resulted in biofilm communities capable of tolerating the presence of PAHs, but only 2 of these exhibited enhanced PAH catabolic gene prevalence coupled with significant degradation of select PAH compounds. Comparisons between inoculant sources highlighted the dependence of this method on appropriate inoculant screening and biostimulation efforts.}, } @article {pmid28060302, year = {2016}, author = {Skogman, ME and Vuorela, PM and Fallarero, A}, title = {A Platform of Anti-biofilm Assays Suited to the Exploration of Natural Compound Libraries.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {118}, pages = {}, pmid = {28060302}, issn = {1940-087X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests/*methods ; Staphylococcus aureus/drug effects ; }, abstract = {Biofilms are regarded as one of the most challenging topics of modern biomedicine, and they are potentially responsible for over 80% of antibiotic-tolerant infections. Biofilms have displayed an exceptionally high tolerance for chemotherapy, which is thought to be multifactorial. For instance, the matrix provides a physical barrier that decreases the penetration of antibiotics into the biofilm. Also, cells within the biofilms are phenotypically diverse. Likely, biofilm resilience arises from a combination of these and other, yet unknown, mechanisms. All of the currently existing antibiotics have been developed against single-cells (planktonic) bacteria. Therefore, so far, a very limited repertoire of molecules exists that can selectively act on mature biofilms. This situation has driven a progressive paradigm shift in drug discovery, in which searching for anti-biofilms has been urged to occupy a more prominent place. An additional challenge is that there are a very limited number of standardized methods for biofilm research, especially those that can be used for large-throughput screening of chemical libraries. Here, an experimental anti-biofilm platform for chemical screening is presented. It uses three assays to measure biofilm viability (with resazurin staining), total biomass (with crystal violet staining), and biofilm matrix (using a wheat germ agglutinin, WGA-fluorescence-based staining of the poly-N-acetyl-glucosamine, PNAG, fraction). All the assays were developed using Staphylococcus aureus as the model bacteria. Examples of how the platform can be used for primary screening as well as for functional characterization of identified anti-biofilm hits are presented. This experimental sequence further allows for the classification of the hits based upon the measured end-points. It also provides information on their mode of action, especially on long-term versus short-term chemotherapeutic effects. Thus, it is very advantageous for the quick identification of high-quality hit compounds that can serve as starting points for various biomedical applications.}, } @article {pmid28060284, year = {2016}, author = {Beaudoin, T and Kennedy, S and Yau, Y and Waters, V}, title = {Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {118}, pages = {}, pmid = {28060284}, issn = {1940-087X}, mesh = {Anti-Bacterial Agents ; Biofilms/*growth & development ; Cystic Fibrosis/drug therapy ; Humans ; Respiratory Tract Infections/drug therapy ; Sputum/*microbiology ; }, abstract = {Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.}, } @article {pmid28056744, year = {2017}, author = {Martín-Rodríguez, AJ and Römling, U}, title = {Nucleotide Second Messenger Signaling as a Target for the Control of Bacterial Biofilm Formation.}, journal = {Current topics in medicinal chemistry}, volume = {}, number = {}, pages = {}, pmid = {28056744}, issn = {1873-4294}, abstract = {Bacterial biofilm formation and associated phenotypes are the major cause of chronic infection in humans. The major regulator of biofilm formation in Gram-negative and Gram-positive bacteria are nucleotide-based second messenger signaling pathways. Nucleotide-based signaling is a ubiquitous signal transduction mechanism in all domains of life that relay changes in the extracellular or intracellular milieu to protein or RNA effectors, leading to adaptive physiological responses. To date, six bona fide nucleotide signaling pathways, (p)ppGpp, cAMP, cGMP, c-di-AMP, c-di-GMP and cGAMP, have been characterized with respect to basic pathway modules and phenotypic and physiological output. Thereby, c-di-GMP is by far the most complex signaling network with up to over 100 turnover protein in some bacteria. While c-di-GMP is a ubiquitous regulator of the motility/sessility switch which translates into the transition from acute to chronic infection, and (p)ppGpp has been shown to be required for persistence, the role of other nucleotide signaling pathways is comparatively poorly characterized. Due to their importance in chronic infections, interference with these signal transduction systems has emerged as a strategy for the control of recurrent bacterial infections. Substantial efforts are being placed in finding small molecules for antibiofilm chemotherapy. The purpose of this review is to provide an overview of our current knowledge on bacterial nucleotide signaling and to provide an up-to-date perspective on small molecules thwarting these transduction pathways. Furthermore, we summarize the high-throughput approaches developed for the discovery of small-molecule inhibitors of nucleotide turnover proteins or effectors from large chemical libraries. Implications and future prospects for the control of biofilm-related infections are discussed. We also highlight the current needs and future directions that could lead to a better understanding of these important signaling networks.}, } @article {pmid28056743, year = {2017}, author = {Moreno, MG and Lombardi, L and Di Luca, M}, title = {Antimicrobial peptides for the control of biofilm formation.}, journal = {Current topics in medicinal chemistry}, volume = {}, number = {}, pages = {}, pmid = {28056743}, issn = {1873-4294}, abstract = {Antimicrobial peptides (AMPs) are an abundant and varied group of molecules recognized as the most ancient components of the innate immune system. They are found in a wide group of organisms including bacteria, plants and animals as a defense mechanism against different kinds of infectious pathogens. Over the past two decades, a fast-growing number of AMPs have been identified/designed and their wide-spectrum antimicrobial activity has been deeply investigated. In recent years, there has been an increasing interest in the use of AMPs as alternative anti-biofilm molecules for the control of biofilm-related infections. Biofilms are sessile communities of microbial cells embedded in a self-produced matrix and characterized by a low metabolic activity. Due to their peculiar physiological properties, bacteria/fungi in biofilms result more resistant to conventional antibiotic therapies compared with their planktonic counterparts. AMPs may be a promising strategy to combat biofilm-related infections, as many of them target the microbial membrane, thus being potentially effective also on metabolically inactive cells. Investigations conducted so far evidenced that these peptides may be active in either eradicating established biofilms or preventing their formation, depending on the specific molecule. Here we present a detailed review of the literature describing the latest results of both in vitro and in vivo experiments aimed at evaluating AMP potential usage in biofilm control. In addition, we provide the reader with an overview on AMP local delivery systems, and we discuss their potential application in the coating of medical indwelling devices.}, } @article {pmid28056742, year = {2017}, author = {de Mello, TP and de Souza Ramos, L and Braga-Silva, LA and Branquinha, MH and Dos Santos, AL}, title = {Fungal Biofilm - A Real Obstacle against an Efficient Therapy: Lessons from Candida.}, journal = {Current topics in medicinal chemistry}, volume = {}, number = {}, pages = {}, pmid = {28056742}, issn = {1873-4294}, abstract = {The past decades have witnessed a dramatic increase in invasive fungal infections, especially caused by different species belonging to the Candida genus. Nowadays, even after many improvements in several medical procedures, Candida infections (candidiasis) still account for an unacceptable high rate of morbimortality in hospital settings. Corroborating this statement, fungal biofilms formed on both abiotic and living surfaces are responsible for an important medical and economic burden, since biofilm lifestyle confers numerous advantages to the pathogens, including high tolerance to environmental stresses such as antimicrobials and host immune responses. Aggravating this scenario, the currently used antifungal drugs have mostly been developed to target exponentially growing fungal cells and are poorly or not effective against biofilm structures. So, the challenges to inhibit biofilm formation (e.g., blocking the fungal adhesion and its fully development due to the changes of physicochemical properties of the inert substrates by covering or impregnating them with antimicrobial compounds, for example, silver nanoparticles) and/or to disarticulate mature biofilm architecture (e.g., by using compounds capable in destabilizing, weakening or destroying the extracellular matrix components, including inhibitors of quorum sensing signals, hydrolytic enzymes, surfactants, chelator agents and biocides) are stimulating researchers around the world to search novel strategies and new chemotherapeutic options to control fungal biofilm. In this context, the present review summarizes some promising approaches and/or strategies that could improve our ability to prevent or eradicate fungal biofilms in medical settings, focusing on the lessons learned with Candida model.}, } @article {pmid28056438, year = {2017}, author = {Bao, Q and Nishimura, N and Kamata, H and Furue, K and Ono, Y and Hosomi, M and Terada, A}, title = {Antibacterial and anti-biofilm efficacy of fluoropolymer coating by a 2,3,5,6-tetrafluoro-p-phenylenedimethanol structure.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {151}, number = {}, pages = {363-371}, doi = {10.1016/j.colsurfb.2016.12.020}, pmid = {28056438}, issn = {1873-4367}, mesh = {Anti-Bacterial Agents/*chemistry ; Bacillus subtilis/drug effects ; Bacterial Adhesion ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Fluorine/*chemistry ; Fluorobenzenes/*chemistry ; Methanol/*chemistry ; Microbial Sensitivity Tests ; Polyethylene Terephthalates/chemistry ; Polymers/*chemistry ; Shear Strength ; Stress, Mechanical ; Surface Properties ; Tomography, Optical Coherence ; }, abstract = {Fluorinated polymers generally function as antibacterial agents, but their anti-biofilm effect remains unresolved. This study investigates the efficacy of fluoropolymers containing 2,3,5,6-tetrafluoro-p-phenylenedimethanol (TFPDM) in preventing biofilm formation by Bacillus subtilis and Escherichia coli (Gram-positive and Gram-negative bacterial species). To this end, TFPDM-based acrylate and epoxy polymers (AF and EF, respectively) and their structural analogues without TFPDM (A and E, respectively) were synthesized. All polymers were coated onto polyethylene terephthalate (PET) sheets. Relative to pristine PET, sheets coated with AF reduced the initial bacterial adhesion (72h) and biofilm formation (30days) of B. subtilis by 27.6% and 68.7% and of E. coli by 89.2% and 93.8%, respectively. The comparable antibacterial and anti-biofilm efficacies were obtained by sheets with EF. The biofilm detachment was substantially facilitated from the AF, compared with the structural analogue without TFPDM (A). In this comprehensive study, the bacterial adhesion and subsequent biofilm formation were prevented by TFPDM-containing polymers effectively.}, } @article {pmid28056366, year = {2017}, author = {Li, J and Hu, L and Zhang, L and Ye, DD and Zhu, X and Liao, Q}, title = {Uneven biofilm and current distribution in three-dimensional macroporous anodes of bio-electrochemical systems composed of graphite electrode arrays.}, journal = {Bioresource technology}, volume = {228}, number = {}, pages = {25-30}, doi = {10.1016/j.biortech.2016.12.092}, pmid = {28056366}, issn = {1873-2976}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms ; Electrodes ; Equipment Design ; *Graphite ; Hydrogen-Ion Concentration ; Porosity ; }, abstract = {A 3-D macroporous anode was constructed using different numbers of graphite rod arrays in fixed-volume bio-electrochemical systems (BESs), and the current and biofilm distribution were investigated by dividing the 3-D anode into several subunits. In the fixed-volume chamber, current production was not significantly improved after the electrode number increased to 36. In the case of 100 electrodes, a significant uneven current distribution was found in the macroporous anode. This was attributed to a differential pH distribution, which resulted from proton accumulation inside the macroporous anode. The pH distribution influenced the biofilm development and led to an uneven biofilm distribution. With respect to current generation, the uneven distribution of both the pH and biofilm contributed to the uneven current distribution. The center had a low pH, which led to less biofilm and a lower contribution to the total current, limiting the performance of the BESs.}, } @article {pmid28053149, year = {2017}, author = {Cernáková, L and Dižová, S and Bujdáková, H}, title = {Employment of methylene blue irradiated with laser light source in photodynamic inactivation of biofilm formed by Candida albicans strain resistant to fluconazole.}, journal = {Medical mycology}, volume = {55}, number = {7}, pages = {748-753}, doi = {10.1093/mmy/myw137}, pmid = {28053149}, issn = {1460-2709}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/radiation effects ; Candida albicans/*drug effects/physiology/radiation effects ; Drug Resistance, Fungal ; Fluconazole/pharmacology ; Humans ; Hyphae/drug effects/radiation effects ; *Lasers ; Methylene Blue/*pharmacology ; Microbial Viability/drug effects ; Photosensitizing Agents/*pharmacology ; }, abstract = {A promising approach for the eradication of biofilm formed by the yeast Candida albicans seems to be photodynamic inactivation (PDI). This work presents a use of methylene blue (MB, 1 mM) irradiated with a red laser (output power 190 mW/cm2, wavelength 660 nm) for the eradication of a biofilm formed by the fluconazole-resistant (FLC-resistant) strain C. albicans CY 1123 compared to the standard strain C. albicans SC5314. The periods of irradiation corresponded to the fluence of 15, 23 and 57 J/cm2. Effectiveness of PDI was evident with following percentage of survived biofilm cells: 24.57, 23.46, and 22.29% for SC5314 and 40.28, 17.91, and 5.89% for CY 1123, respectively, compared to the samples without irradiation. Light and confocal laser scanning microscopy confirmed the effectiveness of PDI. However, the morphological form of C. albicans seems to play an important role as well, since prolonged duration of irradiation did not increase efficiency of PDI on C. albicans SC5314. An experiment with the yeast-to-hyphae transition revealed that the FLC-resistant strain expressed a markedly reduced capacity to form hyphae compared to SC5314. We summarized that PDI was effective on biofilm formed by the FLC-resistant strain, but resistance most likely did not play significant role in PDI. Additionally, we observed differences in susceptibility to PDI between biofilms composed of the mycelia and only of the yeasts, and finally, the employment of a laser in PDI enabled a decreasing period of irradiation while maintaining the high effectiveness of PDI.}, } @article {pmid28051836, year = {2017}, author = {Connolly, E and Millhouse, E and Doyle, R and Culshaw, S and Ramage, G and Moran, GP}, title = {The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation.}, journal = {Molecular oral microbiology}, volume = {32}, number = {1}, pages = {35-47}, doi = {10.1111/omi.12151}, pmid = {28051836}, issn = {2041-1014}, support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adhesins, Bacterial/genetics/*physiology ; Animals ; Bacterial Proteins/*genetics/physiology ; Biofilms/*growth & development ; Cell Line, Tumor ; Cysteine Endopeptidases/physiology ; Epithelial Cells/microbiology ; Erythrocytes/microbiology ; Gingipain Cysteine Endopeptidases ; Hemagglutinins/genetics/physiology ; Host-Parasite Interactions ; Humans ; Lectins/genetics/physiology ; Mouth/microbiology ; Porphyromonas gingivalis/genetics/*physiology ; Sequence Deletion ; Sheep ; }, abstract = {Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation.}, } @article {pmid28051303, year = {2017}, author = {Wu, S and Wang, Y and Liu, N and Dong, G and Sheng, C}, title = {Tackling Fungal Resistance by Biofilm Inhibitors.}, journal = {Journal of medicinal chemistry}, volume = {60}, number = {6}, pages = {2193-2211}, doi = {10.1021/acs.jmedchem.6b01203}, pmid = {28051303}, issn = {1520-4804}, mesh = {Animals ; Antifungal Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; *Drug Discovery/methods ; Drug Resistance, Fungal ; Fungi/*drug effects/*physiology ; Humans ; Models, Molecular ; Mycoses/*drug therapy ; Small Molecule Libraries/chemistry/pharmacology ; }, abstract = {The high incidence and mortality of invasive fungal infections and serious drug resistance have become a global public health issue. The ability of fungal cells to form biofilms is an important reason for the emergence of severe resistance to most clinically available antifungal agents. Targeting fungal biofilm formation by small molecules represents a promising new strategy for the development of novel antifungal agents. This perspective will provide a comprehensive review of fungal biofilm inhibitors. In particular, discovery strategies, chemical structures, antibiofilm/antifungal activities, and structure-activity relationship studies will be discussed. Development of inhibitors to treat biofilm-related resistant fungal infections is a new yet clinically unexploited paradigm, and there is still a long way to go to clinical application. Better understanding of fungal biofilms in combination with systematic drug discovery efforts will pave the way for potential clinical applications.}, } @article {pmid28049105, year = {2017}, author = {Hossain, MI and Paparini, A and Cord-Ruwisch, R}, title = {Rapid adaptation of activated sludge bacteria into a glycogen accumulating biofilm enabling anaerobic BOD uptake.}, journal = {Bioresource technology}, volume = {228}, number = {}, pages = {1-8}, doi = {10.1016/j.biortech.2016.11.102}, pmid = {28049105}, issn = {1873-2976}, mesh = {*Adaptation, Physiological ; Anaerobiosis ; Bacteria/*metabolism ; Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; Bioreactors/*microbiology ; Glycogen/*metabolism ; Microbial Consortia/physiology ; Nitrogen/metabolism ; Oxygen/metabolism ; Polyhydroxyalkanoates/metabolism ; Sewage/*microbiology ; Waste Disposal, Fluid/*instrumentation/methods ; }, abstract = {Glycogen accumulating organisms (GAO) are known to allow anaerobic uptake of biological oxygen demand (BOD) in activated sludge wastewater treatment systems. In this study, we report a rapid transition of suspended activated sludge biomass to a GAO dominated biofilm by selective enrichment using sequences of anaerobic loading followed by aerobic exposure of the biofilm to air. The study showed that within eight weeks, a fully operational, GAO dominated biofilm had developed, enabling complete anaerobic BOD uptake at a rate of 256mg/L/h. The oxygen uptake by the biofilm directly from the atmosphere had been calculated to provide significant energy savings. This study suggests that wastewater treatment plant operators can convert activated sludge systems readily into a "passive aeration" biofilm that avoids costly oxygen transfer to bulk wastewater solution. The described energy efficient BOD removal system provides an opportunity to be coupled with novel nitrogen removal processes such as anammox.}, } @article {pmid28046077, year = {2017}, author = {Schaefers, MM and Liao, TL and Boisvert, NM and Roux, D and Yoder-Himes, D and Priebe, GP}, title = {An Oxygen-Sensing Two-Component System in the Burkholderia cepacia Complex Regulates Biofilm, Intracellular Invasion, and Pathogenicity.}, journal = {PLoS pathogens}, volume = {13}, number = {1}, pages = {e1006116}, pmid = {28046077}, issn = {1553-7374}, mesh = {Anaerobiosis/physiology ; Animals ; Bacterial Proteins/biosynthesis/*genetics/metabolism ; Biofilms/*growth & development ; Burkholderia Infections/complications/microbiology/*pathology ; Burkholderia cepacia complex/genetics/*pathogenicity ; Cell Line ; Cystic Fibrosis/complications ; Disease Models, Animal ; Disease Outbreaks ; Enzyme Activation ; Female ; Flagella/genetics ; Flagellin/genetics ; Gene Expression Regulation, Bacterial/genetics ; Hemeproteins/*genetics/metabolism ; Histidine Kinase ; Humans ; Lac Operon/genetics ; Lung/microbiology ; Mice ; Mice, Inbred C57BL ; Oxygen/metabolism ; Pneumonia/complications/microbiology/*pathology ; Promoter Regions, Genetic/genetics ; }, abstract = {Burkholderia dolosa is a member of the Burkholderia cepacia complex (BCC), which is a group of bacteria that cause chronic lung infection in patients with cystic fibrosis (CF) and can be associated with outbreaks carrying high morbidity and mortality. While investigating the genomic diversity of B. dolosa strains collected from an outbreak among CF patients, we previously identified fixL as a gene showing signs of strong positive selection. This gene has homology to fixL of the rhizobial FixL/FixJ two-component system. The goals of this study were to determine the functions of FixLJ and their role in virulence in B. dolosa. We generated a fixLJ deletion mutant and complemented controls in B. dolosa strain AU0158. Using a fixK-lacZ reporter we found that FixLJ was activated in low oxygen in multiple BCC species. In a murine pneumonia model, the B. dolosa fixLJ deletion mutant was cleared faster from the lungs and spleen than wild-type B. dolosa strain AU0158 at 7 days post infection. Interestingly, the fixLJ deletion mutant made more biofilm, albeit with altered structure, but was less motile than strain AU0158. Using RNA-seq with in vitro grown bacteria, we found ~11% of the genome was differentially expressed in the fixLJ deletion mutant relative to strain AU0158. Multiple flagella-associated genes were down-regulated in the fixLJ deletion mutant, so we also evaluated virulence of a fliC deletion mutant, which lacks a flagellum. We saw no difference in the ability of the fliC deletion mutant to persist in the murine model relative to strain AU0158, suggesting factors other than flagella caused the phenotype of decreased persistence. We found the fixLJ deletion mutant to be less invasive in human lung epithelial and macrophage-like cells. In conclusion, B. dolosa fixLJ is a global regulator that controls biofilm formation, motility, intracellular invasion/persistence, and virulence.}, } @article {pmid28046010, year = {2017}, author = {Liu, J and Stone, VN and Ge, X and Tang, M and Elrami, F and Xu, P}, title = {TetR Family Regulator brpT Modulates Biofilm Formation in Streptococcus sanguinis.}, journal = {PloS one}, volume = {12}, number = {1}, pages = {e0169301}, pmid = {28046010}, issn = {1932-6203}, support = {P30 CA016059/CA/NCI NIH HHS/United States ; R01 DE023078/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Glucans/metabolism ; Mutation/genetics ; Streptococcus sanguis/genetics/*physiology/ultrastructure ; }, abstract = {Biofilms are a key component in bacterial communities providing protection and contributing to infectious diseases. However, mechanisms involved in S. sanguinis biofilm formation have not been clearly elucidated. Here, we report the identification of a novel S. sanguinis TetR repressor, brpT (Biofilm Regulatory Protein TetR), involved in biofilm formation. Deletion of brpT resulted in a significant increase in biofilm formation. Interestingly, the mutant accumulated more water soluble and water insoluble glucans in its biofilm compared to the wild-type and the complemented mutant. The brpT mutation led to an altered biofilm morphology and structure exhibiting a rougher appearance, uneven distribution with more filaments bound to the chains. RNA-sequencing revealed that gtfP, the only glucosyltransferase present in S. sanguinis, was significantly up-regulated. In agreement with these findings, we independently observed that deletion of gtfP in S. sanguinis led to reduced biofilm and low levels of water soluble and insoluble glucans. These results suggest that brpT is involved in the regulation of the gtfP-mediated exopolysaccharide synthesis and controls S. sanguinis biofilm formation. The deletion of brpT may have a potential therapeutic application in regulating S. sanguinis colonization in the oral cavity and the prevention of dental caries.}, } @article {pmid28042660, year = {2017}, author = {Shimizu, T and Harada, K}, title = {Determination of minimum biofilm eradication concentrations of orbifloxacin for canine bacterial uropathogens over different treatment periods.}, journal = {Microbiology and immunology}, volume = {61}, number = {1}, pages = {17-22}, doi = {10.1111/1348-0421.12461}, pmid = {28042660}, issn = {1348-0421}, mesh = {Amoxicillin-Potassium Clavulanate Combination/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/*analogs & derivatives/pharmacology ; Disease Eradication ; Dog Diseases/*drug therapy/*microbiology ; Dogs ; Gram-Negative Bacteria/*drug effects ; Gram-Positive Bacteria/*drug effects ; Microbial Sensitivity Tests ; Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology ; Urinary Tract Infections/microbiology/*veterinary ; }, abstract = {Biofilm formation can cause refractory urinary tract infections (UTIs) in dogs; however, minimum biofilm eradication concentrations (MBECs) of veterinary drugs against canine uropathogens remain to be investigated. In this study, the MBECs of orbifloxacin (OBFX), trimethoprim-sulfamethoxazole (TMS) and amoxicillin/clavulanate (ACV) over different time periods for treatment of canine uropathogenic Escherichia coli (n = 10) were determined. The MBECs of OBFX for other bacterial uropathogens, including Staphylococcus pseudintermedius (n = 5), Pseudomonas aeruginosa (n = 5), Klebsiella pneumoniae (n = 5) and Proteus mirabilis (n = 5) were also determined. Minimum inhibitory concentrations (MICs) were identified for all strains by broth microdilution, and MBECs were determined at 24, 72, and 168 hr using the Calgary biofilm method. The 24 hr MBECs of OBFX, TMS and ACV for the E. coli strains were significantly higher than the MICs (P < 0.05), and the 72 and 168 hr MBECs were significantly lower than those at 24 hr (P < 0.05). In addition, the 24 hr OBFX MBECs for the four other uropathogens were significantly higher than the corresponding MICs (P < 0.05). The 72 and/or 168 hr OBFX MBECs for S. pseudintermedius, K. pneumoniae and P. mirabilis were significantly lower than the 24 hr concentrations (P < 0.05), whereas for P. aeruginosa, no significant difference was found between any of the MBECs (P > 0.05). These data indicate that the administration period and uropathogenic bacterial species are important factors affecting the efficacy of OBFX treatment of biofilm-related UTIs in dogs.}, } @article {pmid28040648, year = {2017}, author = {Cao, X and Wang, H and Li, XQ and Fang, Z and Li, XN}, title = {Enhanced degradation of azo dye by a stacked microbial fuel cell-biofilm electrode reactor coupled system.}, journal = {Bioresource technology}, volume = {227}, number = {}, pages = {273-278}, doi = {10.1016/j.biortech.2016.12.043}, pmid = {28040648}, issn = {1873-2976}, mesh = {Azo Compounds/*chemistry/metabolism ; *Bioelectric Energy Sources ; *Biofilms ; Electrodes ; Gas Chromatography-Mass Spectrometry ; Naphthalenesulfonates/*chemistry/metabolism ; }, abstract = {In this study, a microbial fuel cell (MFC)-biofilm electrode reactor (BER) coupled system was established for degradation of the azo dye Reactive Brilliant Red X-3B. In this system, electrical energy generated by the MFC degrades the azo dye in the BER without the need for an external power supply, and the effluent from the BER was used as the inflow for the MFC, with further degradation. The results indicated that the X-3B removal efficiency was 29.87% higher using this coupled system than in a control group. Moreover, a method was developed to prevent voltage reversal in stacked MFCs. Current was the key factor influencing removal efficiency in the BER. The X-3B degradation pathway and the types and transfer processes of intermediate products were further explored in our system coupled with gas chromatography-mass spectrometry.}, } @article {pmid28040403, year = {2017}, author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L and Lv, B and Yang, Y}, title = {Effects of cerium oxide nanoparticles on the species and distribution of phosphorus in enhanced phosphorus removal sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {227}, number = {}, pages = {393-397}, doi = {10.1016/j.biortech.2016.12.041}, pmid = {28040403}, issn = {1873-2976}, mesh = {*Biofilms ; *Bioreactors ; Cerium/*chemistry/pharmacology ; Metal Nanoparticles/*chemistry ; Nanotechnology/methods ; Phosphorus/*analysis ; Polymers/pharmacology ; X-Ray Diffraction ; }, abstract = {The short term (8h) influences of cerium oxide nanoparticles (CeO2NPs) on the process of phosphorus removal in biofilm were investigated. At concentration of 0.1mg/L, CeO2 NPs posed no impacts on total phosphorus (TP) removal. While at 20mg/L, TP removal efficiency reduced from 85.16% to 59.62%. Results of P distribution analysis and [31]P nuclear magnetic resonance spectroscopy implied that the anaerobic degradation of polyphosphate (polyP) and the release of orthophosphate in extracellular polymeric substances (EPS) were inhibited. After aerobic exposure, the average chain length of polyP in microbial cells and EPS was shorter than control, and monoester and diester phosphates in cells were observed to release into EPS. Moreover, the EPS production and its contribution to P removal increased, while the capacity of EPS in P storage declined. X-ray diffraction analysis and saturation index calculation revealed that the formation of inorganic P precipitation in biofilm was inhibited.}, } @article {pmid28039994, year = {2016}, author = {Ma, D and Wu, J}, title = {Biofilm mitigation by drug (gentamicin)-loaded liposomes promoted by pulsed ultrasound.}, journal = {The Journal of the Acoustical Society of America}, volume = {140}, number = {6}, pages = {EL534}, doi = {10.1121/1.4972336}, pmid = {28039994}, issn = {1520-8524}, mesh = {*Biofilms ; Gentamicins ; Liposomes ; Ralstonia ; Ultrasonic Waves ; }, abstract = {The gentamicin-loaded nano-sized liposomes are shown to penetrate into alginate-based Ralstonia insidiosa bacterial biofilms by acoustic streaming generated by moderate pulsed ultrasound (frequency = 2.25 MHz, 10% duty cycle and spatially and temporally averaged intensity, ISATA ≈ 4.4 W/cm[2]). The liposomes are then burst by the scanned relatively high intensity ultrasound (frequency = 1.1 MHz, 10% duty cycle, the spatially and temporally averaged intensity ISATA ≈ 90 W/cm[2]) in situ, and the gentamicin solution is released from the liposomes resulting in 72% of Ralstonia insidiosa killing.}, } @article {pmid28039788, year = {2017}, author = {Hamedi, S and Shojaosadati, SA and Mohammadi, A}, title = {Evaluation of the catalytic, antibacterial and anti-biofilm activities of the Convolvulus arvensis extract functionalized silver nanoparticles.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {167}, number = {}, pages = {36-44}, doi = {10.1016/j.jphotobiol.2016.12.025}, pmid = {28039788}, issn = {1873-2682}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Catalysis ; Convolvulus/*chemistry ; Humans ; Metal Nanoparticles/*chemistry ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Plant Extracts/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Silver/*chemistry ; Spectrum Analysis ; Staphylococcus aureus/drug effects ; X-Ray Diffraction ; }, abstract = {In this study, a rapid green synthesis of the silver nanoparticles (AgNPs) using leaves extract of Convolvulus arvensis was investigated. UV-Visible spectra showed the SPR band at around 430nm which proved the AgNP formation. The reduction of silver ions to nanoparticles was completed within 150min. Particle size analysis verified the formation of AgNPs with average size of 28nm, while their PDI was 0.2. XRD patterns verified the crystalline nature of produced AgNPs. SEM images verified the presence of spherical nanoparticles with no evidence of aggregations. FTIR analysis verified the involvement of the phenolic compounds in AgNP formation. It was found that the biosynthesized AgNPs have the antibacterial activity against human pathogen E. coli. Also, nanoparticles exhibit biofilm degrading activity against both bacterial strains of S. aureus and P. aeruginosa. Furthermore, the synthesized AgNPs prevented the coagulation of blood samples. The accelerated reduction of methylene blue (MB) in the presence of AgNPs with rate constant of 0.108min[-1], confirmed the catalytic potential of nanoparticles.}, } @article {pmid28038423, year = {2017}, author = {Mielcarek, A and Rodziewicz, J and Janczukowicz, W and Dabrowska, D and Ciesielski, S and Thornton, A and Struk-Sokołowska, J}, title = {Citric acid application for denitrification process support in biofilm reactor.}, journal = {Chemosphere}, volume = {171}, number = {}, pages = {512-519}, doi = {10.1016/j.chemosphere.2016.12.099}, pmid = {28038423}, issn = {1879-1298}, mesh = {Acetates/metabolism ; Bacteria/*drug effects/metabolism ; Bacterial Physiological Phenomena/drug effects ; Biofilms ; Biomass ; Bioreactors/*microbiology ; Citric Acid/*pharmacology ; Denitrification/*drug effects ; Formates/metabolism ; }, abstract = {The study demonstrated that citric acid, as an organic carbon source, can improve denitrification in Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR). The consumption rate of the organic substrate and the denitrification rate were lower during the period of the reactor's acclimatization (cycles 1-60; 71.5 mgCOD L[-1] h[-1] and 17.81 mgN L[-1] h[-1], respectively) than under the steady state conditions (cycles 61-180; 143.8 mgCOD L[-1] h[-1] and 24.38 mgN L[-1] h[-1]). The biomass yield coefficient reached 0.04 ± 0.02 mgTSS· mgCODre[-1] (0.22 ± 0.09 mgTSS mgNre[-1]). Observations revealed the diversified microbiological ecology of the denitrifying bacteria. Citric acid was used mainly by bacteria representing the Trichoccocus genus, which represented above 40% of the sample during the first phase of the process (cycles 1-60). In the second phase (cycles 61-180) the microorganisms the genera that consumed the acetate and formate, as the result of citric acid decomposition were Propionibacterium (5.74%), Agrobacterium (5.23%), Flavobacterium (1.32%), Sphaerotilus (1.35%), Erysipelothrix (1.08%).}, } @article {pmid28036250, year = {2017}, author = {Jin, L and Ko, SR and Lee, CS and Ahn, CY and Lee, JS and Lee, KC and Oh, HM and Lee, HG}, title = {Actinotalea caeni sp. nov., isolated from a sludge sample of a biofilm reactor.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {67}, number = {5}, pages = {1595-1599}, doi = {10.1099/ijsem.0.001769}, pmid = {28036250}, issn = {1466-5034}, mesh = {Actinomycetales/*classification/genetics/isolation & purification ; Bacterial Typing Techniques ; Base Composition ; *Biofilms ; Bioreactors/*microbiology ; DNA, Bacterial/genetics ; Fatty Acids/chemistry ; Glycolipids/chemistry ; Peptidoglycan/chemistry ; Phospholipids/chemistry ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Republic of Korea ; Sequence Analysis, DNA ; Sewage/*microbiology ; Ubiquinone/chemistry ; }, abstract = {A polyphasic taxonomic study was carried out on strain EBR-4-2T isolated from a biofilm reactor in Korea. Cells of the strain were Gram-stain-positive, non-spore-forming, non-motile and rod-shaped. Comparative 16S rRNA gene sequence studies showed the clear affiliation of this strain to the Actinobacteria, and it had the highest pairwise sequence similarities with Actinotalea suaedae EGI 60002T (98.7 %), Actinotalea ferrariae CF5-4T (96.3 %) and Actinotalea fermentans DSM 3133T (96.2 %). Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain formed a clear phylogenetic lineage with the genus Actinotalea. The major fatty acids were identified as C15 : 0 anteiso, C16 : 0, C16 : 0 N alcohol, C15 : 1 anteiso A and C15 : 0 iso. The major cellular polar lipids were diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol and glycolipid. The peptidoglycan type was A4β containing l-Orn-d-Glu. The whole-cell-wall sugars were glucose and ribose. The respiratory quinone was identified as menaquinone MK-10(H4), and the genomic DNA G+C content was determined to be 74.8 mol %. Based on evidence from this polyphasic study, it is proposed that strain EBR-4-2T should be designated as representing a novel species named Actinotalea caeni sp. nov. The type stain is EBR-4-2T (=KCTC 33604T=JCM 30447T).}, } @article {pmid28034758, year = {2017}, author = {Kim, M and Kim, M and Kim, KS}, title = {YmdB-mediated down-regulation of sucA inhibits biofilm formation and induces apramycin susceptibility in Escherichia coli.}, journal = {Biochemical and biophysical research communications}, volume = {483}, number = {1}, pages = {252-257}, doi = {10.1016/j.bbrc.2016.12.157}, pmid = {28034758}, issn = {1090-2104}, mesh = {Biofilms/growth & development ; Carrier Proteins/genetics/*metabolism ; Down-Regulation ; Drug Resistance, Microbial/drug effects/genetics ; Escherichia coli/drug effects/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Ketoglutarate Dehydrogenase Complex/genetics/*metabolism ; Microbial Sensitivity Tests ; Nebramycin/*analogs & derivatives/pharmacology ; Ribonuclease III/genetics/metabolism ; }, abstract = {Antibiotic resistance associated with biofilm formation is a major concern when treating bacterial infections with drugs. The genes and pathways involved in biofilm formation have been extensively studied and are also involved in antibiotic resistance. Recent studies show that overexpression of Escherichia coli (E. coli) YmdB protein alters gene expression profiles and inhibits biofilm formation. Therefore, it is expected that YmdB and its regulated genes play a key role in development of biofilm and antibiotic resistance phenotypes. The present study screened antibiotics to identify those whose susceptibility profiles were regulated by YmdB levels. This protocol identified apramycin. Additional screening for genes negatively regulated by inactivation of RNase III activity via YmdB overexpression revealed that a gene associated with the tricarboxylic acid cycle gene, sucA, was necessary for the YmdB-like phenotype. Taken together, these data suggest that regulation of RNase III activity by trans-acting factors may be the key to identifying genes or pathways connecting biofilm and antibiotic resistance phenotypes. This information could be used to reduce the emergence of biofilm-associated multidrug-resistant bacteria.}, } @article {pmid28034598, year = {2017}, author = {Rossi Gonçalves, I and Dantas, RCC and Ferreira, ML and Batistão, DWDF and Gontijo-Filho, PP and Ribas, RM}, title = {Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {48}, number = {2}, pages = {211-217}, pmid = {28034598}, issn = {1678-4405}, mesh = {Adult ; Aged ; Bacteremia/*epidemiology/microbiology ; Bacterial Proteins/analysis/*genetics ; Biofilms/*growth & development ; Brazil/epidemiology ; Case-Control Studies ; Female ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; Pseudomonas Infections/*epidemiology/microbiology ; Pseudomonas aeruginosa/drug effects/enzymology/*genetics/isolation & purification ; Risk Factors ; Survival Analysis ; Virulence Factors/*genetics ; *beta-Lactam Resistance ; beta-Lactamases/analysis/*genetics ; }, abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case-control study in the Uberlândia Federal University - Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes.}, } @article {pmid28034428, year = {2016}, author = {Zou, J and Li, J and Ni, Y and Wei, S}, title = {Enhancing nitrogen removal from low carbon to nitrogen ratio wastewater by using a novel sequencing batch biofilm reactor.}, journal = {Journal of environmental sciences (China)}, volume = {50}, number = {}, pages = {32-37}, doi = {10.1016/j.jes.2016.03.019}, pmid = {28034428}, issn = {1001-0742}, mesh = {Biofilms ; Bioreactors/*microbiology ; Carbon/analysis/metabolism ; Nitrogen/*analysis/metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry/microbiology ; Water Pollutants, Chemical/*analysis/metabolism ; }, abstract = {Removing nitrogen from wastewater with low chemical oxygen demand/total nitrogen (COD/TN) ratio is a difficult task due to the insufficient carbon source available for denitrification. Therefore, in the present work, a novel sequencing batch biofilm reactor (NSBBR) was developed to enhance the nitrogen removal from wastewater with low COD/TN ratio. The NSBBR was divided into two units separated by a vertical clapboard. Alternate feeding and aeration was performed in the two units, which created an anoxic unit with rich substrate content and an aeration unit deficient in substrate simultaneously. Therefore, the utilization of the influent carbon source for denitrification was increased, leading to higher TN removal compared to conventional SBBR (CSBBR) operation. The results show that the CSBBR removed up to 76.8%, 44.5% and 10.4% of TN, respectively, at three tested COD/TN ratios (9.0, 4.8 and 2.5). In contrast, the TN removal of the NSBBR could reach 81.9%, 60.5% and 26.6%, respectively, at the corresponding COD/TN ratios. Therefore, better TN removal performance could be achieved in the NSBBR, especially at low COD/TN ratios (4.8 and 2.5). Furthermore, it is easy to upgrade a CSBBR into an NSBBR in practice.}, } @article {pmid28033390, year = {2016}, author = {Waters, EM and Rowe, SE and O'Gara, JP and Conlon, BP}, title = {Convergence of Staphylococcus aureus Persister and Biofilm Research: Can Biofilms Be Defined as Communities of Adherent Persister Cells?.}, journal = {PLoS pathogens}, volume = {12}, number = {12}, pages = {e1006012}, pmid = {28033390}, issn = {1553-7374}, support = {K22 AI125501/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Drug Resistance, Microbial/*physiology ; Staphylococcus aureus/*physiology ; }, } @article {pmid28033374, year = {2016}, author = {Stephen, AS and Millhouse, E and Sherry, L and Aduse-Opoku, J and Culshaw, S and Ramage, G and Bradshaw, DJ and Burnett, GR and Allaker, RP}, title = {In Vitro Effect of Porphyromonas gingivalis Methionine Gamma Lyase on Biofilm Composition and Oral Inflammatory Response.}, journal = {PloS one}, volume = {11}, number = {12}, pages = {e0169157}, pmid = {28033374}, issn = {1932-6203}, mesh = {Adhesins, Bacterial/metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/deficiency/genetics/*metabolism ; Cell Line ; Cysteine Endopeptidases/metabolism ; Cytokines/metabolism ; Gene Knockout Techniques ; Gingipain Cysteine Endopeptidases ; Humans ; Inflammation/microbiology ; Keratinocytes/metabolism/microbiology ; Mouth/*microbiology ; Porphyromonas gingivalis/*enzymology/*physiology ; Sulfur/chemistry/metabolism ; }, abstract = {Methanethiol (methyl mercaptan) is an important contributor to oral malodour and periodontal tissue destruction. Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum are key oral microbial species that produce methanethiol via methionine gamma lyase (mgl) activity. The aim of this study was to compare an mgl knockout strain of P. gingivalis with its wild type using a 10-species biofilm co-culture model with oral keratinocytes and its effect on biofilm composition and inflammatory cytokine production. A P. gingivalis mgl knockout strain was constructed using insertion mutagenesis from wild type W50 with gas chromatographic head space analysis confirming lack of methanethiol production. 10-species biofilms consisting of Streptococcus mitis, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp polymorphum, Fusobacterium nucleatum ssp vincentii, Veillonella dispar, Actinomyces naeslundii, Prevotella intermedia and Aggregatibacter actinomycetemcomitans with either the wild type or mutant P. gingivalis were grown on Thermanox cover slips and used to stimulate oral keratinocytes (OKF6-TERT2), under anaerobic conditions for 4 and 24 hours. Biofilms were analysed by quantitative PCR with SYBR Green for changes in microbial ecology. Keratinocyte culture supernatants were analysed using a multiplex bead immunoassay for cytokines. Significant population differences were observed between mutant and wild type biofilms; V. dispar proportions increased (p<0.001), whilst A. naeslundii (p<0.01) and Streptococcus spp. (p<0.05) decreased in mutant biofilms. Keratinocytes produced less IL-8, IL-6 and IL-1α when stimulated with the mutant biofilms compared to wild type. Lack of mgl in P. gingivalis has been shown to affect microbial ecology in vitro, giving rise to a markedly different biofilm composition, with a more pro-inflammatory cytokine response from the keratinocytes observed. A possible role for methanethiol in biofilm formation and cytokine response with subsequent effects on oral malodor and periodontitis is suggested.}, } @article {pmid28032543, year = {2017}, author = {O'Donnell, LE and Alalwan, HKA and Kean, R and Calvert, G and Nile, CJ and Lappin, DF and Robertson, D and Williams, C and Ramage, G and Sherry, L}, title = {Candida albicans biofilm heterogeneity does not influence denture stomatitis but strongly influences denture cleansing capacity.}, journal = {Journal of medical microbiology}, volume = {66}, number = {1}, pages = {54-60}, doi = {10.1099/jmm.0.000419}, pmid = {28032543}, issn = {1473-5644}, mesh = {Antifungal Agents/pharmacology ; *Biofilms ; Candida albicans/drug effects/*growth & development ; Case-Control Studies ; Colony Count, Microbial ; Denture Cleansers/*pharmacology ; Dentures/*microbiology ; Humans ; Microbial Viability/drug effects ; Polymethyl Methacrylate/chemistry ; Real-Time Polymerase Chain Reaction ; Stomatitis, Denture/*microbiology ; Surface Properties/drug effects ; }, abstract = {Approximately 20 % of the UK population wear some form of denture prosthesis, resulting in denture stomatitis in half of these individuals. Candida albicans is primarily attributed as the causative agent, due to its biofilm -forming ability. Recently, there has been increasing evidence of C. albicans biofilm heterogeneity and the negative impact it can have clinically; however, this phenomenon has yet to be studied in relation to denture isolates. The aims of this study were to evaluate C. albicans biofilm formation of clinical denture isolates in a denture environment and to assess antimicrobial activity of common denture cleansers against these tenacious communities. C. albicans isolated from dentures of healthy and diseased individuals was quantified using real-time PCR and biofilm biomass assessed using crystal violet. Biofilm development on the denture substratum poly(methyl methacrylate), Molloplast B and Ufi-gel was determined. Biofilm formation was assessed using metabolic and biomass stains, following treatment with denture hygiene products. Although C. albicans was detected in greater quantities in diseased individuals, it was not associated with increased biofilm biomass. Denture substrata were shown to influence biofilm biomass, with poly(methyl methacrylate) providing the most suitable environment for C. albicans to reside. Of all denture hygiene products tested, Milton had the most effective antimicrobial activity, reducing biofilm biomass and viability the greatest. Overall, our results highlight the complex nature of denture- related disease, and disease development cannot always be attributed to a sole cause. It is the distinct combination of various factors that ultimately determines the pathogenic outcome.}, } @article {pmid28031283, year = {2017}, author = {Yonezawa, H and Osaki, T and Fukutomi, T and Hanawa, T and Kurata, S and Zaman, C and Hojo, F and Kamiya, S}, title = {Diversification of the AlpB Outer Membrane Protein of Helicobacter pylori Affects Biofilm Formation and Cellular Adhesion.}, journal = {Journal of bacteriology}, volume = {199}, number = {6}, pages = {}, pmid = {28031283}, issn = {1098-5530}, mesh = {Bacterial Adhesion/*physiology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/physiology ; Genetic Variation ; Helicobacter pylori/genetics/*physiology ; }, abstract = {Helicobacter pylori is one of the most common causes of bacterial infection in humans, and it forms biofilms on human gastric mucosal epithelium as well as on in vitro abiotic surfaces. Bacterial biofilm is critical not only for environmental survival but also for successful infection. We previously demonstrated that strain TK1402, which was isolated from a Japanese patient with duodenal and gastric ulcers, has high biofilm-forming ability in vitro relative to other strains. In addition, we showed that outer membrane vesicles (OMV) play an important role in biofilm formation. The aim of this study was to analyze which protein(s) in the OMV contributes to biofilm formation in TK1402. We obtained a spontaneous mutant strain derived from TK1402 lacking biofilm-forming ability. The protein profiles of the OMV were compared between this mutant strain and the wild type, and it was found that AlpB, an outer membrane protein in the OMV of the mutant strain, was markedly decreased compared to that of the wild type. Restoration of TK1402 alpB to the mutant strain fully recovered the ability to form biofilm. However, restoration with alpB from other strains demonstrated incomplete recovery of biofilm-forming ability. We therefore inferred that the variable region of AlpB (amino acid positions 121 to 146) was involved in TK1402 biofilm formation. In addition, diversification of the AlpB sequence was shown to affect the ability to adhere to AGS cells. These results demonstrate a new insight into the molecular mechanisms of host colonization by H. pyloriIMPORTANCE Bacterial biofilm is critical not only for environmental survival but also for successful infection. The mechanism of Helicobacter pylori adherence to host cells mediated by cell surface adhesins has been the focus of many studies, but little is known regarding factors involved in H. pylori biofilm formation. Our study demonstrated that AlpB plays an important role in biofilm formation and that this property depends upon the specific sequence of alpB This in turn was shown to be important in the ability to adhere to gastric cells. We anticipate that these results will provide new insight into the molecular mechanisms of H. pylori colonization.}, } @article {pmid28031194, year = {2017}, author = {Saini, H and Vadekeetil, A and Chhibber, S and Harjai, K}, title = {Azithromycin-Ciprofloxacin-Impregnated Urinary Catheters Avert Bacterial Colonization, Biofilm Formation, and Inflammation in a Murine Model of Foreign-Body-Associated Urinary Tract Infections Caused by Pseudomonas aeruginosa.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {3}, pages = {}, pmid = {28031194}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Azithromycin/*pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/immunology/microbiology/*prevention & control ; Ciprofloxacin/*pharmacology ; Coated Materials, Biocompatible/pharmacology ; Delayed-Action Preparations ; Disease Models, Animal ; Female ; Foreign Bodies/drug therapy/immunology/microbiology ; Interleukin-10/biosynthesis/metabolism ; Interleukin-6/biosynthesis/metabolism ; Mice ; Pseudomonas Infections/immunology/microbiology/*prevention & control ; Pseudomonas aeruginosa/drug effects/growth & development ; Tumor Necrosis Factor-alpha/biosynthesis/metabolism ; Urinary Bladder/drug effects/microbiology ; Urinary Catheters/microbiology ; Urinary Tract Infections/immunology/microbiology/*prevention & control ; }, abstract = {Pseudomonas aeruginosa is a multifaceted pathogen causing a variety of biofilm-mediated infections, including catheter-associated urinary tract infections (CAUTIs). The high prevalence of CAUTIs in hospitals, their clinical manifestations, such as urethritis, cystitis, pyelonephritis, meningitis, urosepsis, and death, and the associated economic challenges underscore the need for management of these infections. Biomaterial modification of urinary catheters with two drugs seems an interesting approach to combat CAUTIs by inhibiting biofilm. Previously, we demonstrated the in vitro efficacy of urinary catheters impregnated with azithromycin (AZM) and ciprofloxacin (CIP) against P. aeruginosa Here, we report how these coated catheters impact the course of CAUTI induced by P. aeruginosa in a murine model. CAUTI was established in female LACA mice with uncoated or AZM-CIP-coated silicone implants in the bladder, followed by transurethral inoculation of 10[8] CFU/ml of biofilm cells of P. aeruginosa PAO1. AZM-CIP-coated implants (i) prevented biofilm formation on the implant's surface (P ≤ 0.01), (ii) restricted bacterial colonization in the bladder and kidney (P < 0.0001), (iii) averted bacteriuria (P < 0.0001), and (iv) exhibited no major histopathological changes for 28 days in comparison to uncoated implants, which showed persistent CAUTI. Antibiotic implants also overcame implant-mediated inflammation, as characterized by trivial levels of inflammatory markers such as malondialdehyde (P < 0.001), myeloperoxidase (P < 0.05), reactive oxygen species (P ≤ 0.001), and reactive nitrogen intermediates (P < 0.01) in comparison to those in uncoated implants. Further, AZM-CIP-coated implants showed immunomodulation by manipulating the release of inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-10 to the benefit of the host. Overall, the study demonstrates long-term in vivo effectiveness of AZM-CIP-impregnated catheters, which may possibly be a key to success in preventing CAUTIs.}, } @article {pmid28025903, year = {2017}, author = {Mahata, D and Nag, A and Mandal, SM and Nando, GB}, title = {Antibacterial coating on in-line suction respiratory catheter to inhibit the bacterial biofilm formation using renewable cardanyl methacrylate copolymer.}, journal = {Journal of biomaterials science. Polymer edition}, volume = {28}, number = {4}, pages = {365-379}, doi = {10.1080/09205063.2016.1277623}, pmid = {28025903}, issn = {1568-5624}, mesh = {Anti-Infective Agents/chemistry/pharmacology ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Catheter-Related Infections/microbiology ; Catheters/*microbiology ; Coated Materials, Biocompatible/chemistry/pharmacology ; HEK293 Cells ; Humans ; Mechanical Phenomena ; Methacrylates/*chemistry ; Polymerization ; Polystyrenes/chemistry ; *Respiration ; Staphylococcus aureus/drug effects ; Suction/*instrumentation ; }, abstract = {Health-care materials associated with infections are very common in hospital admitted patients. There are generally infected by contact with the catheter or other multipurpose devices which are contacted with microbes. The respiratory infections associated with the pathogens having strong biofilm forming ability on catheter surface, causes life-threatening in every year. Therefore, a catheter coating material is of great interest which inhibits the biofilm formation of pathogens on a catheter to prevent respiratory infections. In this study, we synthesized cardanol containing copolymers as antimicrobial healthcare material via radical polymerization of cardanyl methacrylate (CMA) with styrene (St) monomer in presence of free radical initiator. The rate of polymerization was drastically reduced with the increase of feeding CMA monomer in copolymer. The thermal and mechanical properties were found to increase with incorporation of cardanol moiety in brittle and hard polystyrene. This soft copolymer was grafted onto polyvinyl chloride respiratory catheter which showed high antibacterial activity, inhibit the biofilm formation and also prevent bacterial adhesion. Therefore, the developed coating material on respiratory catheter surface is effective way to control the respiratory catheter-associated nosocomial infections.}, } @article {pmid28025643, year = {2016}, author = {Garner, B and Brown, E and Taplin, M and Garcia, A and Williams-Mapp, B}, title = {Transferrin Impacts Bacillus thuringiensis Biofilm Levels.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {3628268}, pmid = {28025643}, issn = {2314-6141}, support = {HHSN268201300048C/HL/NHLBI NIH HHS/United States ; }, mesh = {Bacillus thuringiensis/*physiology ; Biofilms/*drug effects/*growth & development ; Transferrin/*pharmacology ; }, abstract = {The present study examined the impact of transferrin on Bacillus thuringiensis biofilms. Three commercial strains, an environmental strain (33679), the type strain (10792), and an isolate from a diseased insect (700872), were cultured in iron restricted minimal medium. All strains produced biofilm when grown in vinyl plates at 30°C. B. thuringiensis 33679 had a biofilm biomass more than twice the concentration exhibited by the other strains. The addition of transferrin resulted in slightly increased growth yields for 2 of the 3 strains tested, including 33679. In contrast, the addition of 50 μg/mL of transferrin resulted in an 80% decrease in biofilm levels for strain 33679. When the growth temperature was increased to 37°C, the addition of 50 μg/mL of transferrin increased culture turbidity for only strain 33679. Biofilm levels were again decreased in strain 33679 at 37°C. Growth of B. thuringiensis cultures in polystyrene resulted in a decrease in overall growth yields at 30°C, with biofilm levels significantly decreased for 33679 in the presence of transferrin. These findings demonstrate that transferrin impacts biofilm formation in select strains of B. thuringiensis. Identification of these differences in biofilm regulation may be beneficial in elucidating potential virulence mechanisms among the differing strains.}, } @article {pmid28019691, year = {2017}, author = {Nakagami, G and Schultz, G and Gibson, DJ and Phillips, P and Kitamura, A and Minematsu, T and Miyagaki, T and Hayashi, A and Sasaki, S and Sugama, J and Sanada, H}, title = {Biofilm detection by wound blotting can predict slough development in pressure ulcers: A prospective observational study.}, journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society}, volume = {25}, number = {1}, pages = {131-138}, doi = {10.1111/wrr.12505}, pmid = {28019691}, issn = {1524-475X}, mesh = {*Biofilms ; Collodion ; Cytological Techniques/methods ; Debridement ; Humans ; Membranes, Artificial ; Pressure Ulcer/*microbiology/*physiopathology ; Prospective Studies ; Tissue Adhesives ; }, abstract = {Bacteria have been found to form multicellular aggregates which have collectively been termed "biofilms." It is hypothesized that biofilm formation is a means to protect bacterial cells including protection form the immune response of humans. This protective mechanism is believed to explain persistent chronic wound infections. At times, the biofilms are abundant enough to see, and remove by simple wiping. However, recent evidence has shown that the removal of these visible portions are not sufficient, and that biofilms can continue to form even with daily wiping. In this work, we tested an approach to detect the biofilms which are present after clinically wiping or sharp wound debridement. Our method is based on a variation of impression cytology in which a nitrocellulose membrane was used to collect surface biofilm components, which were then differentially stained. In this prospective study, members of an interdisciplinary pressure ulcer team at a university hospital tested our method's ability to predict the generation of wound slough in the week that followed each blotting. A total of 70 blots collected from 23 pressure ulcers produced 27 wounds negative for staining and 43 positive. In the negative blots 55.6% were found to have decreased wound slough, while 81.4% with positive staining had either increase or unchanged wound slough generation. These results lead to an odds ratio of positive blotting cases of 9.37 (95% confidence intervals: 2.47-35.5, p = 0.001) for slough formation; suggesting that the changes in wound slough formation can be predicted clinically using a non-invasive wound blotting method.}, } @article {pmid28018482, year = {2016}, author = {Fica, ZT and Sims, RC}, title = {Algae-based biofilm productivity utilizing dairy wastewater: effects of temperature and organic carbon concentration.}, journal = {Journal of biological engineering}, volume = {10}, number = {}, pages = {18}, pmid = {28018482}, issn = {1754-1611}, abstract = {BACKGROUND: Biofilm-based microalgal growth was determined as functions of organic chemical loading and water temperature utilizing dairy wastewater from a full-scale dairy farm. The dairy industry is a significant source of wastewater worldwide that could provide an inexpensive and nutrient rich feedstock for the cultivation of algae biomass for use in downstream processing of animal feed and aquaculture applications. Algal biomass was cultivated using a Rotating Algal Biofilm Reactor (RABR) system. The RABR is a biofilm-based technology that has been designed and used to remediate municipal wastewater and was applied to treat dairy wastewater through nutrient uptake, and simultaneously provide biomass for the production of renewable bioproducts.

RESULTS: Aerial algal biofilm growth rates in dairy wastewater at 7 and 27 °C temperatures were shown to be 4.55 ± 0.17 g/m[2]-day and 7.57 ± 1.12 g/m[2]-day ash free dry weight (AFDW), respectively. Analysis of Variance (ANOVA) calculations indicated that both an increase in temperature of the wastewater and an increase in the level of organic carbon, from 300 to 1200 mg L[-1], contributed significantly to an increase in the rate of biomass growth in the system. However, ANOVA results indicated that the interaction of temperature and organic carbon content was not significantly related to the biofilm-based growth rate.

CONCLUSION: A microalgae-based biofilm reactor was successfully used to treat turbid dairy wastewater. Temperature and organic carbon concentration had a statistically significant effect on algae-based biofilm productivity and treatment of dairy wastewater. The relationships between temperature, TOC, and productivity developed in this study may be used in the design and assessment of wastewater remediation systems and biomass production systems utilizing algae-based biofilm reactors for treating dairy wastes.}, } @article {pmid28018312, year = {2016}, author = {Tettmann, B and Niewerth, C and Kirschhöfer, F and Neidig, A and Dötsch, A and Brenner-Weiss, G and Fetzner, S and Overhage, J}, title = {Enzyme-Mediated Quenching of the Pseudomonas Quinolone Signal (PQS) Promotes Biofilm Formation of Pseudomonas aeruginosa by Increasing Iron Availability.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1978}, pmid = {28018312}, issn = {1664-302X}, abstract = {The 2-alkyl-3-hydroxy-4(1H)-quinolone 2,4-dioxygenase HodC was previously described to cleave the Pseudomonas quinolone signal, PQS, which is exclusively used in the complex quorum sensing (QS) system of Pseudomonas aeruginosa, an opportunistic pathogen employing QS to regulate virulence and biofilm development. Degradation of PQS by exogenous addition of HodC to planktonic cells of P. aeruginosa attenuated production of virulence factors, and reduced virulence in planta. However, proteolytic cleavage reduced the efficacy of HodC. Here, we identified the secreted protease LasB of P. aeruginosa to be responsible for HodC degradation. In static biofilms of the P. aeruginosa PA14 lasB::Tn mutant, the catalytic activity of HodC led to an increase in viable biomass in newly formed but also in established biofilms, and reduced the expression of genes involved in iron metabolism and siderophore production, such as pvdS, pvdL, pvdA, and pvdQ. This is likely due to an increase in the levels of bioavailable iron by degradation of PQS, which is able to sequester iron from the surrounding environment. Thus, HodC, despite its ability to quench the production of virulence factors, is contraindicated for combating P. aeruginosa biofilms.}, } @article {pmid28017482, year = {2017}, author = {Velázquez-Guadarrama, N and Olivares-Cervantes, AL and Salinas, E and Martínez, L and Escorcia, M and Oropeza, R and Rosas, I}, title = {Presence of environmental coagulase-positive staphylococci, their clonal relationship, resistance factors and ability to form biofilm.}, journal = {Revista Argentina de microbiologia}, volume = {49}, number = {1}, pages = {15-23}, doi = {10.1016/j.ram.2016.08.006}, pmid = {28017482}, issn = {0325-7541}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Cats ; *Coagulase ; Humans ; Microbial Sensitivity Tests ; *R Factors ; RNA, Ribosomal, 16S ; Staphylococcal Infections ; *Staphylococcus/isolation & purification ; }, abstract = {Coagulase-positive staphylococci (CoPS) are opportunistic pathogens carrying various mechanisms of resistance that have a large number of virulence factors, and whose ability to induce illness is associated with the host. This study aimed to investigate the presence of environmental coagulase-positive staphylococci, their susceptibility profile, clonal relationship and ability to form biofilm. The 16S rRNA genes from CoPS isolates were analyzed, and their antibiotic susceptibility was evaluated using the agar dilution method in accordance with Clinical and Laboratory Standards Institute guidelines. The clonal profile was obtained by pulsed-field gel electrophoresis (PFGE) and biofilm formation was measured by a crystal violet retention assay. A total of 72 Staphylococcus spp. strains were isolated from air, metal surfaces, and nostrils from humans, dogs, cats, and birds. Three species were identified: Staphylococcus aureus (17%), Staphylococcus intermedius (63%), and Staphylococcus pseudintermedius (21%). Ninety three percent (93%) of the strains were resistant to at least one of 13 tested antibiotics. S. pseudintermedius strains were the only resistant ones to methicillin while most of these isolates were multidrug-resistant, had significantly higher ability to form biofilm and PFGE grouped into seven different patterns, without showing clonal dispersion among animals and environmental isolates. This study suggests that dogs, cat, and air are environmental sources potentially carrying multidrug-resistant S. pseudintermedius, which survives in different environments through biofilm formation and multidrug resistance, characteristics that can be transmitted horizontally to other bacteria and exacerbate the problem of antibiotic resistance in humans.}, } @article {pmid28013514, year = {2017}, author = {Segev-Zarko, LA and Shai, Y}, title = {Methods for Investigating Biofilm Inhibition and Degradation by Antimicrobial Peptides.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1548}, number = {}, pages = {309-322}, doi = {10.1007/978-1-4939-6737-7_22}, pmid = {28013514}, issn = {1940-6029}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Bacteria/drug effects/growth & development/metabolism ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Protein Multimerization ; Protein Structure, Secondary ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {Multidrug-resistant bacteria are a growing problem worldwide. One extensively studied resistance mechanism is biofilm colonization-microbial colonies formed by many Gram-positive and Gram-negative bacteria species. Cationic antimicrobial peptides (AMPs) are innate immune system molecules serving as a first line of defense in fighting invading pathogens. The AMPs' underlying mechanism and biophysical properties required for anti-biofilm activity are not fully known. Here we present protocols for investigating AMPs' biological activity against major stages of biofilm life cycle, namely, planktonic stage (MIC assay), initial adhesion to surfaces (bacterial attachment assay), and formation or degradation of sessile microcolonies (biofilm formation and degradation assays). Furthermore, we demonstrate experiments that allow determination and comparison between peptide biophysical properties (secondary structure, hydrophobicity, and oligomerization) and how they affect their mechanism (peptide-binding assays) of anti-biofilm activity.}, } @article {pmid28012985, year = {2017}, author = {Bao, X and Jia, X and Chen, L and Peters, BM and Lin, CW and Chen, D and Li, L and Li, B and Li, Y and Xu, Z and Shirtliff, ME}, title = {Effect of polymyxin resistance (pmr) on biofilm formation of Cronobacter sakazakii.}, journal = {Microbial pathogenesis}, volume = {106}, number = {}, pages = {16-19}, doi = {10.1016/j.micpath.2016.12.012}, pmid = {28012985}, issn = {1096-1208}, mesh = {Bacterial Proteins/*genetics/*pharmacology ; Biofilms/*drug effects/*growth & development ; Biomass ; Cronobacter sakazakii/*genetics/growth & development/*metabolism ; DNA, Bacterial/genetics ; Down-Regulation/genetics ; Food Contamination/prevention & control ; Gene Expression Regulation, Bacterial/drug effects/genetics ; Genome, Bacterial ; Genotype ; Microbial Viability ; Microscopy, Electron, Scanning ; Mutation ; Sequence Analysis, RNA ; Transcriptome/genetics ; Up-Regulation/genetics ; }, abstract = {Cronobacter sakazakii (C.sakazakii) has been identified as a wide-spread conditioned pathogen associated with series of serious illnesses, such as neonatal meningitis, enterocolitis, bacteremia or sepsis. As food safety is concerned, microbial biofilm has been considered to be a potential source of food contamination. The current study aims to investigate the ability of biofilm formation of two C. sakazakii strains (wild type BAA 894 and pmrA mutant). Crystal violet (CV), XTT (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino carbonyl)-2H-(tetrazolium hydroxide)] assays, and scanning electron microscopy (SEM) are performed on different time points during biofilm formation of C. sakazakii strains. Furthermore, RNA-seq strategy is utilized and the transcriptome data is analyzed to study the expression of genes related to biofilm formation along with whole genome sequencing. For biomass, in the first 24 h, pmrA mutant produced approximately 5 times than wildtype. However, the wild type exhibited more biomass than pmrA mutant during the post maturation stage (7-14 d). In addition, the wildtype showed higher viability than pmrA mutant during the whole biofilm formation. This study represents the first evidence on the biofilm formation of C. sakazakii pmrA mutant, which may further aid in the prevention and control for the food contamination caused by C. sakazakii.}, } @article {pmid28012375, year = {2017}, author = {Wang, J and Wang, Y and Bai, J and Liu, Z and Song, X and Yan, D and Abiyu, A and Zhao, Z and Yan, D}, title = {High efficiency of inorganic nitrogen removal by integrating biofilm-electrode with constructed wetland: Autotrophic denitrifying bacteria analysis.}, journal = {Bioresource technology}, volume = {227}, number = {}, pages = {7-14}, doi = {10.1016/j.biortech.2016.12.046}, pmid = {28012375}, issn = {1873-2976}, mesh = {Autotrophic Processes ; Bacteria ; *Biofilms ; Bioreactors/*microbiology ; *Denitrification ; Electrodes ; Nitrogen/analysis/chemistry ; Wastewater/chemistry ; Water Purification/*methods ; *Wetlands ; }, abstract = {The constructed wetland coupled with biofilm-electrode reactor (CW-BER) is a novel technology to treat wastewater with a relatively high level of total inorganic nitrogen (TIN) concentration. The main objective of this study is to investigate the effects of C/Ns, TIN concentrations, current intensities, and pH on the removal of nitrogen in CW-BER; a control system (CW) was also constructed and operated with similar influent conditions. Results indicated that the current, inorganic carbon source and hydrogen generated by the micro-electric field could significantly improve the inorganic nitrogen removal with in CW-BER, and the enhancement of average removal rate on NH3-N, NO3-N, and TIN was approximately maintained at 5-28%, 5-26%, and 3-24%, respectively. The appropriate operation conditions were I=10mA and pH=7.5 in CW-BER. In addition, high-throughput sequencing analysis implied that the CW-BER reactor has been improved with the relative abundance of autotrophic denitrifying bacteria (Thiobacillus sp.).}, } @article {pmid28012315, year = {2017}, author = {Huang, C and Shi, Y and Xue, J and Zhang, Y and Gamal El-Din, M and Liu, Y}, title = {Comparison of biomass from integrated fixed-film activated sludge (IFAS), moving bed biofilm reactor (MBBR) and membrane bioreactor (MBR) treating recalcitrant organics: Importance of attached biomass.}, journal = {Journal of hazardous materials}, volume = {326}, number = {}, pages = {120-129}, doi = {10.1016/j.jhazmat.2016.12.015}, pmid = {28012315}, issn = {1873-3336}, mesh = {Aerobiosis ; Ammonium Compounds/chemistry ; Biodegradation, Environmental ; *Biofilms ; *Biomass ; Bioreactors/*microbiology ; Carboxylic Acids ; Industrial Waste ; Oil and Gas Fields ; Organic Chemicals/chemistry ; Petroleum ; RNA, Ribosomal, 16S/metabolism ; Sewage/*microbiology ; Water Microbiology ; Water Pollutants, Chemical/*chemistry ; }, abstract = {This study compared microbial characteristics and oil sands process-affected water (OSPW) treatment performance of five types of microbial biomass (MBBR-biofilm, IFAS-biofilm, IFAS-floc, MBR-aerobic-floc, and MBR-anoxic-floc) cultivated from three types of bioreactors (MBBR, IFAS, and MBR) in batch experiments. Chemical oxygen demand (COD), ammonium, acid extractable fraction (AEF), and naphthenic acids (NAs) removals efficiencies were distinctly different between suspended and attached bacterial aggregates and between aerobic and anoxic suspended flocs. MBR-aerobic-floc and MBR-anoxic-floc demonstrated COD removal efficiencies higher than microbial aggregates obtained from MBBR and IFAS, MBBR and IFAS biofilm had higher AEF removal efficiencies than those obtained using flocs. MBBR-biofilm demonstrated the most efficient NAs removal from OSPW. NAs degradation efficiency was highly dependent on the carbon number and NA cyclization number according to UPLC/HRMS analysis. Mono- and di-oxidized NAs were the dominant oxy-NA species in OSPW samples. Microbial analysis with quantitative polymerase chain reaction (q-PCR) indicated that the bacterial 16S rRNA gene abundance was significantly higher in the batch bioreactors with suspended flocs than in those with biofilm, the NSR gene abundance in the MBR-anoxic bioreactor was significantly lower than that in aerobic batch bioreactors, and denitrifiers were more abundant in the suspended phase of the activated sludge flocs.}, } @article {pmid28011696, year = {2017}, author = {Picozzi, C and Antoniani, D and Vigentini, I and Foschino, R and Kneifel, W}, title = {Genotypic characterization and biofilm formation of Shiga toxin-producing Escherichia coli.}, journal = {FEMS microbiology letters}, volume = {364}, number = {2}, pages = {}, doi = {10.1093/femsle/fnw291}, pmid = {28011696}, issn = {1574-6968}, mesh = {Adhesins, Bacterial/genetics ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Cellulose/metabolism ; Electrophoresis, Gel, Pulsed-Field ; Escherichia coli Proteins/genetics ; Feces/microbiology ; Food Microbiology ; *Genotype ; Humans ; Molecular Typing ; Serogroup ; Shiga Toxin 1/genetics ; Shiga Toxin 2/genetics ; Shiga-Toxigenic Escherichia coli/classification/*genetics/isolation & purification/*physiology ; }, abstract = {Shiga toxin-producing Escherichia coli (STEC) are recognized as one of the most dangerous foodborne pathogens. The production of Shiga toxins together with intimin protein is among the main virulence factors. However, the ability to form biofilm can protect bacteria against environmental factors (i.e. desiccation, exposure to UV rays, predation, etc.) and sanitization procedures (cleaning, rinsing, chlorination), increasing their survival on food products and in manufacturing plants. Forty-five isolates collected from food and fecal samples were genotyped by pulsed field gel electrophoresis analysis with XbaI restriction enzyme and investigated by searching for toxins (stx1, stx2) and intimin (eae) genes and serogroup (O157, O26, O145, O111, O103 and O104). Afterward, the ability to develop biofilm in microtiter assay and the production of adhesive curli fimbriae and cellulose on agar plates were tested. Our study demonstrated that biofilm formation has a great variability among STEC strains and cannot be related to a specific pulsotype nor even to serogroup or presence of virulence genes.}, } @article {pmid28011336, year = {2017}, author = {Geilich, BM and Gelfat, I and Sridhar, S and van de Ven, AL and Webster, TJ}, title = {Superparamagnetic iron oxide-encapsulating polymersome nanocarriers for biofilm eradication.}, journal = {Biomaterials}, volume = {119}, number = {}, pages = {78-85}, doi = {10.1016/j.biomaterials.2016.12.011}, pmid = {28011336}, issn = {1878-5905}, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/*drug effects/*growth & development ; Dextrans/*administration & dosage/chemistry ; Magnetite Nanoparticles/*administration & dosage/chemistry ; Nanocapsules/*administration & dosage/chemistry/ultrastructure ; Particle Size ; Polymers/*chemistry ; Staphylococcus aureus/*drug effects/physiology ; Sterilization/methods ; }, abstract = {The rising prevalence and severity of antibiotic-resistant biofilm infections poses an alarming threat to public health worldwide. Here, biocompatible multi-compartment nanocarriers were synthesized to contain both hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) and the hydrophilic antibiotic methicillin for the treatment of medical device-associated infections. SPION co-encapsulation was found to confer unique properties, enhancing both nanocarrier relaxivity and magneticity compared to individual SPIONs. These iron oxide-encapsulating polymersomes (IOPs) penetrated 20 μm thick Staphylococcus epidermidis biofilms with high efficiency following the application of an external magnetic field. Three-dimensional laser scanning confocal microscopy revealed differential bacteria death as a function of drug and SPION loading. Complete eradication of all bacteria throughout the biofilm thickness was achieved using an optimized IOP formulation containing 40 μg/mL SPION and 20 μg/mL of methicillin. Importantly, this formulation was selectively toxic towards methicillin-resistant biofilm cells but not towards mammalian cells. These novel iron oxide-encapsulating polymersomes demonstrate that it is possible to overcome antibiotic-resistant biofilms by controlling the positioning of nanocarriers containing two or more therapeutics.}, } @article {pmid28007984, year = {2017}, author = {Coyte, KZ and Tabuteau, H and Gaffney, EA and Foster, KR and Durham, WM}, title = {Microbial competition in porous environments can select against rapid biofilm growth.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {2}, pages = {E161-E170}, pmid = {28007984}, issn = {1091-6490}, support = {242670/ERC_/European Research Council/International ; }, mesh = {Biofilms/*growth & development ; Ecosystem ; Escherichia coli/*physiology ; Game Theory ; Hydrodynamics ; *Microbial Interactions ; Models, Theoretical ; Porosity ; }, abstract = {Microbes often live in dense communities called biofilms, where competition between strains and species is fundamental to both evolution and community function. Although biofilms are commonly found in soil-like porous environments, the study of microbial interactions has largely focused on biofilms growing on flat, planar surfaces. Here, we use microfluidic experiments, mechanistic models, and game theory to study how porous media hydrodynamics can mediate competition between bacterial genotypes. Our experiments reveal a fundamental challenge faced by microbial strains that live in porous environments: cells that rapidly form biofilms tend to block their access to fluid flow and redirect resources to competitors. To understand how these dynamics influence the evolution of bacterial growth rates, we couple a model of flow-biofilm interaction with a game theory analysis. This investigation revealed that hydrodynamic interactions between competing genotypes give rise to an evolutionarily stable growth rate that stands in stark contrast with that observed in typical laboratory experiments: cells within a biofilm can outcompete other genotypes by growing more slowly. Our work reveals that hydrodynamics can profoundly affect how bacteria compete and evolve in porous environments, the habitat where most bacteria live.}, } @article {pmid28005941, year = {2016}, author = {Baldry, M and Nielsen, A and Bojer, MS and Zhao, Y and Friberg, C and Ifrah, D and Glasser Heede, N and Larsen, TO and Frøkiær, H and Frees, D and Zhang, L and Dai, H and Ingmer, H}, title = {Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus.}, journal = {PloS one}, volume = {11}, number = {12}, pages = {e0168305}, pmid = {28005941}, issn = {1932-6203}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Staphylococcal Infections/genetics/metabolism/microbiology ; Staphylococcus aureus/*genetics/metabolism ; Virulence/drug effects/*genetics ; Virulence Factors/*genetics ; Xanthones/*pharmacology ; }, abstract = {Staphylococcus aureus is a serious human pathogen and antibiotic resistant, community-associated strains, such as the methicillin resistant S. aureus (MRSA) strain USA300, continue to spread. To avoid resistance, anti-virulence therapy has been proposed where toxicity is targeted rather than viability. Previously we have shown that norlichexanthone, a small non-reduced tricyclic polyketide produced by fungi and lichens, reduces expression of hla encoding α-hemolysin as well as the regulatory RNAIII of the agr quorum sensing system in S. aureus 8325-4. The aim of the present study was to further characterise the mode of action of norlichexanthone and its effect on biofilm formation. We find that norlichexanthone reduces expression of both hla and RNAIII also in strain USA300. Structurally, norlichexanthone resembles ω-hydroxyemodin that recently was shown to bind the agr two component response regulator, AgrA, which controls expression of RNAIII and the phenol soluble modulins responsible for human neutrophil killing. We show that norlichexanthone reduces S. aureus toxicity towards human neutrophils and interferes directly with AgrA binding to its DNA target. In contrast to ω-hydroxyemodin however, norlichexanthone reduces staphylococcal biofilm formation. Transcriptomic analysis revealed that genes regulated by the SaeRS two-component system are repressed by norlichexanthone when compared to untreated cells, an effect that was mitigated in strain Newman carrying a partially constitutive SaeRS system. Our data show that norlichexanthone treatment reduces expression of key virulence factors in CA-MRSA strain USA300 via AgrA binding and represses biofilm formation.}, } @article {pmid28005180, year = {2017}, author = {Alvarado-Gutiérrez, ML and Ruiz-Ordaz, N and Galíndez-Mayer, J and Santoyo-Tepole, F and Curiel-Quesada, E and García-Mena, J and Ahuatzi-Chacón, D}, title = {Kinetics of carbendazim degradation in a horizontal tubular biofilm reactor.}, journal = {Bioprocess and biosystems engineering}, volume = {40}, number = {4}, pages = {519-528}, doi = {10.1007/s00449-016-1717-3}, pmid = {28005180}, issn = {1615-7605}, mesh = {Bacteria/*metabolism ; Benzimidazoles/*metabolism ; *Bioreactors ; Carbamates/*metabolism ; Kinetics ; *Membranes, Artificial ; *Microbial Consortia ; }, abstract = {The fungicide carbendazim is an ecotoxic agent affecting aquatic biota. Due to its suspected hormone-disrupting effects, it is considered a "priority hazard substance" by the Water Framework Directive of the European Commission, and its degradation is of major concern. In this work, a horizontal tubular biofilm reactor (HTBR) operating in plug-flow regime was used to study the kinetics of carbendazim removal by an acclimated microbial consortium. The reactor was operated in steady state continuous culture at eight different carbendazim loading rates. The concentrations of the fungicide were determined at several distances of the HTBR. At the loading rates tested, the highest instantaneous removal rates were observed in the first section of the tubular biofilm reactor. No evidence of inhibition of the catabolic activity of the microbial community was found. Strains of the genera Flectobacillus, Klebsiella, Stenotrophomonas, and Flavobacterium were identified in the biofilm; the last three degrade carbendazim in axenic culture.}, } @article {pmid28004034, year = {2016}, author = {Paula-Ramos, L and da Rocha Santos, CE and Camargo Reis Mello, D and Nishiama Theodoro, L and De Oliveira, FE and Back Brito, GN and Junqueira, JC and Jorge, AOC and de Oliveira, LD}, title = {Klebsiella pneumoniae Planktonic and Biofilm Reduction by Different Plant Extracts: In Vitro Study.}, journal = {TheScientificWorldJournal}, volume = {2016}, number = {}, pages = {3521413}, pmid = {28004034}, issn = {1537-744X}, mesh = {Amaranthaceae/chemistry ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Juglans/chemistry ; Klebsiella pneumoniae/*drug effects/growth & development ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Rosmarinus/chemistry ; }, abstract = {This study evaluated the action of Pfaffia paniculata K., Juglans regia L., and Rosmarius officinalis L. extracts against planktonic form and biofilm of Klebsiella pneumoniae (ATCC 4352). Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) values were determined for each extract by microdilution broth method, according to Clinical and Laboratory Standards Institute. Next, antimicrobial activity of the extracts on biofilm was analyzed. For this, standardized suspension at 10[7] UFC/mL of K. pneumoniae was distributed into 96-well microplates (n = 10) and after 48 h at 37°C and biofilm was subjected to treatment for 5 min with the extracts at a concentration of 200 mg/mL. ANOVA and Tukey tests (5%) were used to verify statistical significant reduction (p < 0.05) of planktonic form and biofilm. P paniculata K., R. officinalis L., and J. regia L. showed reductions in biomass of 55.6, 58.1, and 18.65% and cell viability reduction of 72.4, 65.1, and 31.5%, respectively. The reduction obtained with P. paniculata and R. officinalis extracts was similar to the reduction obtained with chlorhexidine digluconate 2%. In conclusion, all extracts have microbicidal action on the planktonic form but only P. paniculata K. and R. officinalis L. were effective against biofilm.}, } @article {pmid28003605, year = {2017}, author = {Oguchi, R and Takahashi, Y and Shimazu, K and Urano-Tashiro, Y and Kawarai, T and Konishi, K and Karibe, H}, title = {Contribution of Streptococcus gordonii Hsa Adhesin to Biofilm Formation.}, journal = {Japanese journal of infectious diseases}, volume = {70}, number = {4}, pages = {399-404}, doi = {10.7883/yoken.JJID.2016.492}, pmid = {28003605}, issn = {1884-2836}, mesh = {Adhesins, Bacterial/genetics/*metabolism ; Biofilms/*growth & development ; Carrier Proteins/genetics/*metabolism ; Glycoconjugates/metabolism ; Hemagglutinins, Viral ; Mutation ; Streptococcus gordonii/metabolism/*physiology ; }, abstract = {Adhesion of oral mitis group streptococci, such as Streptococcus gordonii, to acquired pellicle on the tooth surface is the first step in oral biofilm formation. S. gordonii strain DL1 possesses an Hsa adhesin, which recognizes the terminal sialic acid of host sialoglycoconjugates. The aim of the present study was to investigate the role of the Hsa adhesin in biofilm formation. The biofilm-forming ability of a S. gordonii hsa mutant on microtiter plates pre-coated with saliva, fetuin, or mucin was significantly lower than that of wild-type strain DL1. In contrast, no significant difference in biofilm-forming ability was observed in plates pre-coated with bovine serum albumin, which does not contain sialic acid. The biofilm-forming ability of strain DL1 in saliva-coated microtiter plates was also significantly reduced when the plate was pre-treated with neuraminidase. The sialic acid-dependent biofilm-forming ability of different wild-type S. gordonii strains varied. However, Southern and western blot analyses showed that all the tested wild-type strains possessed and expressed hsa homologs, respectively. These results indicate that the binding of Hsa adhesin to sialoglycoconjugates is associated with biofilm formation of S. gordonii DL1, and imply variation in the contribution of Hsa and its homologs to S. gordonii biofilm formation.}, } @article {pmid28003049, year = {2017}, author = {Guo, Z and Xie, C and Zhang, P and Zhang, J and Wang, G and He, X and Ma, Y and Zhao, B and Zhang, Z}, title = {Toxicity and transformation of graphene oxide and reduced graphene oxide in bacteria biofilm.}, journal = {The Science of the total environment}, volume = {580}, number = {}, pages = {1300-1308}, doi = {10.1016/j.scitotenv.2016.12.093}, pmid = {28003049}, issn = {1879-1026}, mesh = {*Biofilms ; Biotransformation ; Escherichia coli/metabolism ; Graphite/*toxicity ; Oxides/*toxicity ; Staphylococcus aureus/metabolism ; }, abstract = {Impact of graphene based material (GNMs) on bacteria biofilm has not been well understood yet. In this study, we compared the impact of graphene oxide (GO) and reduced graphene oxide (rGO) on biofilm formation and development in Luria-Bertani (LB) medium using Escherichia coli and Staphylococcus aureus as models. GO significantly enhanced the cell growth, biofilm formation, and biofilm development even up to a concentration of 500mg/L. In contrast, rGO (≥50mg/L) strongly inhibited cell growth and biofilm formation. However, the inhibitory effects of rGO (50mg/L and 100mg/L) were attenuated in the mature phase (>24h) and eliminated at 48h. GO at 250mg/L decreased the reactive oxygen species (ROS) levels in biofilm and extracellular region at mature phase. ROS levels were significantly increased by rGO at early phase, while they returned to the same levels as control at mature phase. These results suggest that oxidative stress contributed to the inhibitory effect of rGO on bacterial biofilm. We further found that supplement of extracellular polymeric substances (EPS) in the growth medium attenuated the inhibitory effect of rGO on the growth of developed biofilm. XPS results showed that rGO were oxidized to GO which can enhance the bacterial growth. We deduced that the elimination of the toxicity of rGO at mature phase was contributed by EPS protection and the oxidation of rGO. This study provides new insights into the interaction of GNMs with bacteria biofilm.}, } @article {pmid28002827, year = {2017}, author = {Nomura, R and Yoneyama, R and Naka, S and Otsugu, M and Ogaya, Y and Hatakeyama, R and Morita, Y and Maruo, J and Matsumoto-Nakano, M and Yamada, O and Nakano, K}, title = {The in vivo Inhibition of Oral Biofilm Accumulation and Streptococcus mutans by Ceramic Water.}, journal = {Caries research}, volume = {51}, number = {1}, pages = {58-67}, doi = {10.1159/000452343}, pmid = {28002827}, issn = {1421-976X}, mesh = {Adolescent ; Adult ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Dental Caries/microbiology ; Dental Plaque/microbiology ; Female ; Humans ; Male ; Microbial Viability/drug effects ; Microscopy, Confocal ; Saliva/microbiology ; Silver/*pharmacology ; Streptococcus mutans/*drug effects ; Time Factors ; Titanium/*pharmacology ; Water/pharmacology ; Young Adult ; }, abstract = {Combustion-synthesized titanium carbide ceramics uniformly disperse silver, producing silver ions and hydroxyl radicals in water. This generates antimicrobial activity against various bacteria. One such bacterium is Streptococcus mutans, a gram-positive anaerobic bacterium known as a major pathogen of dental caries. In this study, we analyzed the inhibition of oral biofilms and S. mutans by ceramic water in in vitro and human studies. S. mutans strains showed significantly lower antimicrobial and sucrose-dependent adhesion activity in the presence of ceramic powder compared with untreated culture medium. Confocal microscopy revealed that S. mutans biofilm structures with ceramic powder were thin and coarse. Twenty-seven volunteers (13 males, 14 females; 18-37 years old, mean 25.2 years) were enrolled for subsequent studies. After each meal, one group was asked to rinse with ceramic water while the other rinsed with untreated water for 1 week. After 1 week, the rinsing contents were switched between the groups and the same protocol was followed for an additional week. After rinsing with ceramic water, the average plaque score was 43.0 ± 3.7, which was significantly lower than the baseline value (74.1 ± 5.7, p < 0.001). However, no significant difference was observed when rinsing with untreated water. In addition, the total number of S. mutans in saliva was significantly reduced after rinsing with ceramic water compared with untreated water (p < 0.05). These results suggest that ceramic water possesses antimicrobial activity against S. mutans and inhibits biofilm formation. Rinsing with ceramic water can also inhibit dental plaque formation and S. mutans colonization in humans.}, } @article {pmid28001217, year = {2016}, author = {Romero, CM and Vivacqua, CG and Abdulhamid, MB and Baigori, MD and Slanis, AC and Allori, MC and Tereschuk, ML}, title = {Biofilm inhibition activity of traditional medicinal plants from Northwestern Argentina against native pathogen and environmental microorganisms.}, journal = {Revista da Sociedade Brasileira de Medicina Tropical}, volume = {49}, number = {6}, pages = {703-712}, doi = {10.1590/0037-8682-0452-2016}, pmid = {28001217}, issn = {1678-9849}, mesh = {Anacardiaceae/chemistry ; Argentina ; Bacillus/*drug effects ; Biofilms/*drug effects/growth & development ; Cell Adhesion/drug effects ; Environmental Microbiology ; Humans ; Larrea/chemistry ; Lycium/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plants, Medicinal/*chemistry/classification ; Staphylococcus/*drug effects ; Tagetes/chemistry ; }, abstract = {INTRODUCTION:: Plants have been commonly used in popular medicine of most cultures for the treatment of disease. The in vitro antimicrobial activity of certain Argentine plants used in traditional medicine has been reported. The aim of this study was to investigate the antimicrobial, anti-biofilm, and anti-cell adherence activities of native plants (Larrea divaricata, Tagetes minuta, Tessaria absinthioides, Lycium chilense, and Schinus fasciculatus) collected in northwestern Argentina.

METHODS:: The activities of the five plant species were evaluated in Bacillus strains and clinical strains of coagulase-negative Staphylococcus isolated from northwestern Argentina and identified by 16S rDNA.

RESULT:: Lycium chilense and Schinus fasciculatus were the most effective antimicrobial plant extracts (15.62µg/ml and 62.50µg/ml for Staphylococcus sp. Mcr1 and Bacillus sp. Mcn4, respectively). The highest (66%) anti-biofilm activity against Bacillus sp. Mcn4 was observed with T. absinthioides and L. divaricate extracts. The highest (68%) anti-biofilm activity against Staphylococcus sp. Mcr1 was observed with L. chilense extract. T. minuta, T. absinthioides, and L. divaricata showed percentages of anti-biofilm activity of between 55% and 62%. The anti-adherence effects of T. minuta and L. chilense observed in Bacillus sp. Mcn4 reflected a difference of only 22% and 10%, respectively, between anti-adherence and biofilm inhibition. Thus, the inhibition of biofilm could be related to cell adherence. In Staphylococcus sp. Mcr1, all plant extracts produced low anti-adherence percentages.

CONCLUSION:: These five species may represent a source of alternative drugs derived from plant extracts, based on ethnobotanical knowledge from northwest Argentina.}, } @article {pmid28000785, year = {2016}, author = {Pusic, P and Tata, M and Wolfinger, MT and Sonnleitner, E and Häussler, S and Bläsi, U}, title = {Cross-regulation by CrcZ RNA controls anoxic biofilm formation in Pseudomonas aeruginosa.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {39621}, pmid = {28000785}, issn = {2045-2322}, mesh = {Bacterial Proteins/*genetics ; *Biofilms ; Carbon/chemistry ; Catabolite Repression ; Dose-Response Relationship, Drug ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Mutation ; NAD ; Oxidation-Reduction ; Oxygen/chemistry ; Plasmids/metabolism ; Protein Biosynthesis ; Pseudomonas aeruginosa/*genetics ; RNA/*analysis ; RNA, Bacterial/genetics ; RNA, Messenger/genetics ; Sequence Analysis, RNA ; Transcription, Genetic ; Transcriptome ; }, abstract = {Pseudomonas aeruginosa (PA) can thrive in anaerobic biofilms in the lungs of cystic fibrosis (CF) patients. Here, we show that CrcZ is the most abundant PA14 RNA bound to the global regulator Hfq in anoxic biofilms grown in cystic fibrosis sputum medium. Hfq was crucial for anoxic biofilm formation. This observation complied with an RNAseq based transcriptome analysis and follow up studies that implicated Hfq in regulation of a central step preceding denitrification. CrcZ is known to act as a decoy that sequesters Hfq during relief of carbon catabolite repression, which in turn alleviates Hfq-mediated translational repression of catabolic genes. We therefore inferred that CrcZ indirectly impacts on biofilm formation by competing for Hfq. This hypothesis was supported by the findings that over-production of CrcZ mirrored the biofilm phenotype of the hfq deletion mutant, and that deletion of the crcZ gene augmented biofilm formation. To our knowledge, this is the first example where competition for Hfq by CrcZ cross-regulates an Hfq-dependent physiological process unrelated to carbon metabolism.}, } @article {pmid27999568, year = {2016}, author = {Liu, X and Wang, D and Yu, C and Li, T and Liu, J and Sun, S}, title = {Potential Antifungal Targets against a Candida Biofilm Based on an Enzyme in the Arachidonic Acid Cascade-A Review.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1925}, pmid = {27999568}, issn = {1664-302X}, abstract = {Candida is an important opportunistic fungal pathogen, especially in biofilm associated infections. The formation of a Candida biofilm can decrease Candida sensitivity to antifungal drugs and cause drug resistance. Although many effective antifungal drugs are available, their applications are limited due to their high toxicity and cost. Seeking new antifungal agents that are effective against biofilm-associated infection is an urgent need. Many research efforts are underway, and some progress has been made in this field. It has been shown that the arachidonic acid cascade plays an important role in fungal morphogenesis and pathogenicity. Notably, prostaglandin E2 (PGE2) can promote the formation of a Candida biofilm. Recently, the inhibition of PGE2 has received much attention. Studies have shown that cyclooxygenase (COX) inhibitors, such as aspirin, ibuprofen, and indomethacin, combined with fluconazole can significantly reduce Candida adhesion and biofilm development and increase fluconazole susceptibility; the MIC of fluconazole can be decrease from 64 to 2 μg/ml when used in combination with ibuprofen. In addition, in vivo studies have also confirmed the antifungal activities of these inhibitors. In this article, we mainly review the relationship between PGE2 and Candida biofilm, summarize the antifungal activities of COX inhibitors and analyze the possible antifungal activity of microsomal prostaglandin E synthase-1 (MPGES-1) inhibitors; additionally, other factors that influence PGE2 production are also discussed. Hopefully this review can disclose potential antifungal targets based on the arachidonic acid cascade and provide a prevailing strategy to alleviate Candida albicans biofilm formation.}, } @article {pmid27999440, year = {2017}, author = {Aguilar-Colomer, A and Doadrio, JC and Pérez-Jorge, C and Manzano, M and Vallet-Regí, M and Esteban, J}, title = {Antibacterial effect of antibiotic-loaded SBA-15 on biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis.}, journal = {The Journal of antibiotics}, volume = {70}, number = {3}, pages = {259-263}, pmid = {27999440}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Bacterial Load ; Biocompatible Materials ; Biofilms/drug effects ; Ceramics ; Drug Combinations ; Drug Delivery Systems ; Microbial Sensitivity Tests ; Rifampin/administration & dosage/pharmacology ; Silicon Dioxide/administration & dosage/*pharmacology ; Staphylococcus aureus/*drug effects/physiology ; Staphylococcus epidermidis/*drug effects/physiology ; Vancomycin/administration & dosage/pharmacology ; }, abstract = {Staphylococcus aureus and Staphylococcus epidermidis are human pathogens involved in implant-related infections. During those diseases, they are able to form biofilms showing resistance to the effect of many different antibiotics. Drug delivery systems allow a local and effective delivery of antibiotics at high concentrations in the infected tissue without causing the cytotoxic effects commonly linked to systemic administration. We report the use of a porous ceramic biomaterial, such as SBA-15 loaded with antibiotics, to deliver them directly to the infected tissue. SBA-15 discs were loaded with Vancomycin, Rifampin and a combination of both, introduced in a suspension of S. aureus 15981 and S. epidermidis ATCC 35984 and incubated during 6 and 24 h. A statistically significant decrease in the biofilm density and the number of viable bacteria was detected for all antibiotics at 6 h in both bacteria. Rifampin showed an increase in the biofilm density and the number of viable bacteria at 24 h. No differences were detected between Vancomycin and the combination of antibiotics. S. epidermidis was more sensitive to the effect of the antibiotics than S. aureus. Here we have demonstrated that SBA-15 is able to act as an effective drug delivery system not only from a pharmaceutical point of view, but also from a biological one.}, } @article {pmid27999071, year = {2017}, author = {Ruppen, C and Hemphill, A and Sendi, P}, title = {In vitro activity of gentamicin as an adjunct to penicillin against biofilm group B Streptococcus.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {2}, pages = {444-447}, doi = {10.1093/jac/dkw447}, pmid = {27999071}, issn = {1460-2091}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; *Drug Synergism ; Drug Therapy, Combination/methods ; Gentamicins/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Osteoarthritis/drug therapy ; Penicillins/*pharmacology ; Prosthesis-Related Infections/drug therapy ; Streptococcus agalactiae/*drug effects/*physiology ; }, abstract = {OBJECTIVES: Group B Streptococcus (GBS) increasingly causes invasive disease in non-pregnant adults, particularly in elderly persons and those with underlying diseases. Combination therapy with penicillin plus gentamicin has been suggested for periprosthetic joint infection. The postulated synergism of this combination is based on experiments with planktonic bacteria. We aimed to assess the efficacy of this combination against sessile bacteria.

METHODS: Four different GBS strains were used. We compared results of MICs with those of minimal biofilm eradication concentrations (MBECs), applied chequerboard assays to the MBEC device and calculated the fractional inhibitory concentration index. Synergism was evaluated with time-kill assays against bacteria adherent to cement beads, using penicillin (0.048, 0.2 and 3 mg/L), gentamicin (4 and 12.5 mg/L) and a combination thereof. Results were evaluated via colony counting after sonication of beads and scanning electron microscopy.

RESULTS: MBEC/MIC ratios were 2000-4000 for penicillin and 1-4 for gentamicin. In chequerboard assays, synergism was observed in all four isolates. In time-kill assays, penicillin and 12.5 mg/L gentamicin showed synergism in two isolates. In the other two isolates 12.5 mg/L gentamicin alone was as efficient as the combination therapy.

CONCLUSIONS: These in vitro investigations show activity of 12.5 mg/L gentamicin, alone or as an adjunct to penicillin, against four strains of biofilm GBS. This concentration cannot be achieved in bone with systemic administration, but can be reached if administered locally. The combination of systemic penicillin plus local gentamicin indicates a potential application in orthopaedic-device-associated GBS infections. Studies with a larger number of strains are required to confirm our results.}, } @article {pmid27997400, year = {2016}, author = {Kopec, L and Drewnowski, J and Kopec, A}, title = {The application of moving bed biofilm reactor to denitrification process after trickling filters.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {12}, pages = {2909-2916}, doi = {10.2166/wst.2016.460}, pmid = {27997400}, issn = {0273-1223}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; *Bioreactors ; *Denitrification ; Nitrogen/chemistry ; Sewage/chemistry ; Water Purification/*instrumentation ; }, abstract = {The paper presents research of a prototype moving bed biofilm reactor (MBBR). The device was used for the post-denitrification process and was installed at the end of a technological system consisting of a septic tank and two trickling filters. The concentrations of suspended biomass and biomass attached on the EvU Perl moving bed surface were determined. The impact of the external organic carbon concentration on the denitrification rate and efficiency of total nitrogen removal was also examined. The study showed that the greater part of the biomass was in the suspended form and only 6% of the total biomass was attached to the surface of the moving bed. Abrasion forces between carriers of the moving bed caused the fast stripping of attached microorganisms and formation of flocs. Thanks to immobilization of a small amount of biomass, the MBBR was less prone to leaching of the biomass and the occurrence of scum and swelling sludge. It was revealed that the maximum rate of denitrification was an average of 0.73 gN-NO[3]/gDM·d (DM: dry matter), and was achieved when the reactor was maintained in external organic carbon concentration exceeding 300 mgO2/dm[3] chemical oxygen demand. The reactor proved to be an effective device enabling the increase of total nitrogen removal from 53.5% to 86.0%.}, } @article {pmid27997398, year = {2016}, author = {Guisado, IM and Purswani, J and Catón-Alcubierre, L and González-López, J and Pozo, C}, title = {Toxicity and biofilm-based selection for methyl tert-butyl ether bioremediation technology.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {12}, pages = {2889-2897}, doi = {10.2166/wst.2016.461}, pmid = {27997398}, issn = {0273-1223}, mesh = {Agrobacterium/*physiology ; Biodegradation, Environmental ; *Biofilms ; Culture Media ; Methyl Ethers/*metabolism/toxicity ; Paenibacillus/*physiology ; Rhodococcus/*physiology ; }, abstract = {Extractive membrane biofilm reactor (EMBFR) technology offers productive solutions for volatile and semi-volatile compound removal from water bodies. In this study, the bacterial strains Paenibacillus etheri SH7[T] (CECT 8558), Agrobacterium sp. MS2 (CECT 8557) and Rhodococcus ruber strains A5 (CECT 8556), EE6 (CECT 8612) and EE1 (CECT 8555), previously isolated from fuel-contaminated sites, were tested for adherence on tubular semipermeable membranes in laboratory-scale systems designed for methyl tert-butyl ether (MTBE) bioremediation. Biofilm formation on the membrane surface was evaluated through observation by field-emission scanning electron microscope (FESEM) as well as the acute toxicity (as EC50) of the bacterial growth media. Moreover, extracellular polymeric substance (EPS) production for each strain under different MTBE concentrations was measured. Strains A5 and MS2 were biofilm producers and their adherence increased when the MTBE flowed through the inner tubular semipermeable membrane. No biofilm was formed by Paenibacillus etheri SH7[T], nevertheless, the latter and strain MS2 exhibited the lowest toxicity after growth on the EMBFR. The results obtained from FESEM and toxicity analysis demonstrate that bacterial strains R. ruber EE6, A5, P. etheri SH7[T] and Agrobacterium sp. MS2 could be excellent candidates to be used as selective inocula in EMBFR technology for MTBE bioremediation.}, } @article {pmid27995790, year = {2017}, author = {Kim, LH and Chong, TH}, title = {Physiological Responses of Salinity-Stressed Vibrio sp. and the Effect on the Biofilm Formation on a Nanofiltration Membrane.}, journal = {Environmental science & technology}, volume = {51}, number = {3}, pages = {1249-1258}, doi = {10.1021/acs.est.6b02904}, pmid = {27995790}, issn = {1520-5851}, mesh = {*Biofilms ; Biofouling ; Membranes, Artificial ; *Salinity ; Vibrio ; }, abstract = {This study evaluated the effects of salinity on the physiological characteristics of Vibrio sp. B2 and biofilm formation on nanofiltration (NF) membrane coupons used in the high recovery seawater desalination process. The test conditions were at 0.6, 1.2, and 2.4 M sodium chloride (NaCl), equivalent to salinity of seawater, brine at 50% and 75% water recovery, respectively. High salinity inhibited the cell growth rate but increased the viability and bacterial membrane integrity. In addition, protein and eDNA concentrations of salinity-stressed bacteria were increased at 1.2 and 2.4 M NaCl. In particular, protein concentration was linearly correlated with the NaCl concentration. Similarly, less biofilm formation on the NF membrane coupon (without permeation flux) was observed by the salinity-stressed bacteria; however, the production of extracellular polymeric substances (EPS) was significantly increased as compared to control, and protein was an influential factor for biofilm formation. This study shows that salinity-stressed bacteria have a high potential to cause biofouling on membrane surface as the bacteria still maintain the cell activity and overproduce EPS. The potential of biofilm formation by the salinity-stressed bacteria has not been reported. Therefore, the findings are important to understand the mechanisms of membrane biofouling in a high salinity environment.}, } @article {pmid27994455, year = {2016}, author = {Shi, SF and Jia, JF and Guo, XK and Zhao, YP and Chen, DS and Guo, YY and Zhang, XL}, title = {Reduced Staphylococcus aureus biofilm formation in the presence of chitosan-coated iron oxide nanoparticles.}, journal = {International journal of nanomedicine}, volume = {11}, number = {}, pages = {6499-6506}, pmid = {27994455}, issn = {1178-2013}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Chitosan/*chemistry ; Ferric Compounds/*chemistry ; Microscopy, Electron, Scanning ; Nanoparticles/administration & dosage/*chemistry ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus can adhere to most foreign materials and form biofilm on the surface of medical devices. Biofilm infections are difficult to resolve. The goal of this in vitro study was to explore the use of chitosan-coated nanoparticles to prevent biofilm formation. For this purpose, S. aureus was seeded in 96-well plates to incubate with chitosan-coated iron oxide nanoparticles in order to study the efficiency of biofilm formation inhibition. The biofilm bacteria count was determined using the spread plate method; biomass formation was measured using the crystal violet staining method. Confocal laser scanning microscopy and scanning electron microscopy were used to study the biofilm formation. The results showed decreased viable bacteria numbers and biomass formation when incubated with chitosan-coated iron oxide nanoparticles at all test concentrations. Confocal laser scanning microscopy showed increased dead bacteria and thinner biofilm when incubated with nanoparticles at a concentration of 500 µg/mL. Scanning electron microscopy revealed that chitosan-coated iron oxide nanoparticles inhibited biofilm formation in polystyrene plates. Future studies should be performed to study these nanoparticles for anti-infective use.}, } @article {pmid27993856, year = {2017}, author = {Zaborskyte, G and Andersen, JB and Kragh, KN and Ciofu, O}, title = {Real-Time Monitoring of nfxB Mutant Occurrence and Dynamics in Pseudomonas aeruginosa Biofilm Exposed to Subinhibitory Concentrations of Ciprofloxacin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {3}, pages = {}, pmid = {27993856}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Biofilms/drug effects/growth & development ; Ciprofloxacin/*pharmacology ; DNA-Binding Proteins/*genetics/metabolism ; Drug Resistance, Bacterial/*genetics ; *Gene Expression Regulation, Bacterial ; Genes, Reporter ; Green Fluorescent Proteins/genetics/metabolism ; Luminescent Proteins/genetics/metabolism ; Membrane Proteins/genetics/metabolism ; Membrane Transport Proteins/genetics/metabolism ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Fluorescence ; *Mutation ; Pseudomonas aeruginosa/drug effects/*genetics/growth & development/metabolism ; Recombinant Fusion Proteins/genetics/metabolism ; Rheology ; Selection, Genetic ; Time-Lapse Imaging ; Transcription Factors/*genetics/metabolism ; }, abstract = {Biofilm infections caused by Pseudomonas aeruginosa are frequently treated with ciprofloxacin (CIP); however, resistance rapidly develops. One of the primary resistance mechanisms is the overexpression of the MexCD-OprJ pump due to a mutation in nfxB, encoding the transcriptional repressor of this pump. The aim of this study was to investigate the effect of subinhibitory concentrations of CIP on the occurrence of nfxB mutants in the wild-type PAO1 flow cell biofilm model. For this purpose, we constructed fluorescent reporter strains (PAO1 background) with an mCherry tag for constitutive red fluorescence and chromosomal transcriptional fusion between the P mexCD promoter and gfp leading to green fluorescence upon mutation of nfxB We observed a rapid development of nfxB mutants by live confocal laser scanning microscopy (CLSM) imaging of the flow cell biofilm (reaching 80 to 90% of the whole population) when treated with 1/10 minimal biofilm inhibitory concentration of CIP for 24 h and 96 h. Based on the observed developmental stages, we propose that nfxB mutants emerged de novo in the biofilm during CIP treatment from filamentous cells, which might have arisen due to the stress responses induced by CIP. Identical nfxB mutations were found in fluorescent colonies from the same flow cell biofilm, especially in 24-h biofilms, suggesting selection and clonal expansion of the mutants during biofilm growth. Our findings point at the significant role of high-enough antibiotic dosages or appropriate combination therapy to avoid the emergence of resistant mutants in biofilms.}, } @article {pmid27992644, year = {2017}, author = {Ribaudo, N and Li, X and Davis, B and Wood, TK and Huang, ZJ}, title = {A Genome-Scale Modeling Approach to Quantify Biofilm Component Growth of Salmonella Typhimurium.}, journal = {Journal of food science}, volume = {82}, number = {1}, pages = {154-166}, doi = {10.1111/1750-3841.13565}, pmid = {27992644}, issn = {1750-3841}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Drug Resistance ; *Genes, Bacterial ; *Genome, Bacterial ; Humans ; *Models, Biological ; Salmonella typhimurium/genetics/growth & development/metabolism/*physiology ; Virulence ; }, abstract = {Salmonella typhimurium (S. typhimurium) is an extremely dangerous foodborne bacterium that infects both animal and human subjects, causing fatal diseases around the world. Salmonella's robust virulence, antibiotic-resistant nature, and capacity to survive under harsh conditions are largely due to its ability to form resilient biofilms. Multiple genome-scale metabolic models have been developed to study the complex and diverse nature of this organism's metabolism; however, none of these models fully integrated the reactions and mechanisms required to study the influence of biofilm formation. This work developed a systems-level approach to study the adjustment of intracellular metabolism of S. typhimurium during biofilm formation. The most advanced metabolic reconstruction currently available, STM_v1.0, was 1st extended to include the formation of the extracellular biofilm matrix. Flux balance analysis was then employed to study the influence of biofilm formation on cellular growth rate and the production rates of biofilm components. With biofilm formation present, biomass growth was examined under nutrient rich and nutrient deficient conditions, resulting in overall growth rates of 0.8675 and 0.6238 h[-1] respectively. Investigation of intracellular flux variation during biofilm formation resulted in the elucidation of 32 crucial reactions, and associated genes, whose fluxes most significantly adapt during the physiological response. Experimental data were found in the literature to validate the importance of these genes for the biofilm formation of S. typhimurium. This preliminary investigation on the adjustment of intracellular metabolism of S. typhimurium during biofilm formation will serve as a platform to generate hypotheses for further experimental study on the biofilm formation of this virulent bacterium.}, } @article {pmid27992189, year = {2017}, author = {Takahashi, H and Nadres, ET and Kuroda, K}, title = {Cationic Amphiphilic Polymers with Antimicrobial Activity for Oral Care Applications: Eradication of S. mutans Biofilm.}, journal = {Biomacromolecules}, volume = {18}, number = {1}, pages = {257-265}, pmid = {27992189}, issn = {1526-4602}, support = {U01 DE023771/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Cations/*chemistry ; Humans ; Microbial Sensitivity Tests ; Oral Hygiene/*methods ; Polymers/chemistry/*pharmacology ; Streptococcus mutans/*drug effects/growth & development ; }, abstract = {The antibacterial and antibiofilm activities of cationic amphiphilic methacrylate polymers against cariogenic bacterium S. mutans were investigated. Cationic homopolymer PE0 and copolymer PE31 containing 31 mol % of ethyl methacrylate were synthesized by reversible addition-fragmentation chain transfer polymerization. These polymers displayed bactericidal activity toward S. mutans and prevented biofilm formation by killing the planktonic bacteria. At a concentration of 1000 μg/mL when incubated for 2 h the polymers reduced >80% of biofilm biomass. When the polymer assay solution with the biofilm was vigorously mixed using a pipet for 30 s, >50% of biofilm mass was removed at a polymer concentration of 250 μg/mL. Chlorhexidine and a cationic surfactant failed to reduce the biofilm mass at the same concentration. PE0 was the most effective in removing biofilm and did not show any significant cytotoxicity to human gingival fibroblast and periodontal ligament stem cells when incubated for 10 min.}, } @article {pmid27989720, year = {2017}, author = {Howlin, RP and Winnard, C and Angus, EM and Frapwell, CJ and Webb, JS and Cooper, JJ and Aiken, SS and Bishop, JY and Stoodley, P}, title = {Prevention of Propionibacterium acnes biofilm formation in prosthetic infections in vitro.}, journal = {Journal of shoulder and elbow surgery}, volume = {26}, number = {4}, pages = {553-563}, doi = {10.1016/j.jse.2016.09.042}, pmid = {27989720}, issn = {1532-6500}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Bone Cements ; Calcium Sulfate ; Gram-Positive Bacterial Infections/*prevention & control ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Propionibacterium acnes ; Prosthesis-Related Infections/*prevention & control ; Tobramycin/*pharmacology ; Vancomycin/*pharmacology ; }, abstract = {BACKGROUND: The role of Propionibacterium acnes in shoulder arthroplasty and broadly in orthopedic prosthetic infections has historically been underestimated, with biofilm formation identified as a key virulence factor attributed to invasive isolates. With an often indolent clinical course, P acnes infection can be difficult to detect and treat. This study investigates absorbable cements loaded with a broad-spectrum antibiotic combination as an effective preventive strategy to combat P acnes biofilms.

METHODS: P acnes biofilm formation on an unloaded synthetic calcium sulfate (CaSO4) bone void filler cement bead was evaluated by scanning electron microscopy over a period of 14 days. Beads loaded with tobramycin alone or vancomycin alone (as comparative controls) and beads loaded with a vancomycin-tobramycin dual treatment were assessed for their ability to eradicate planktonic P acnes, prevent biofilm formation, and eradicate preformed biofilms using a combination of viable-cell counts, confocal microscopy, and scanning electron microscopy.

RESULTS: P acnes surface colonization and biofilm formation on unloaded CaSO4 beads was slow. Beads loaded with antibiotics were able to kill planktonic cultures of 10[6] colony-forming units/mL, prevent bacterial colonization, and significantly reduce biofilm formation over periods of weeks. Complete eradication of established biofilms was achieved with a contact time of 1 week.

CONCLUSIONS: This study demonstrates that antibiotic-loaded CaSO4 beads may represent an effective antibacterial and antibiofilm strategy to combat prosthetic infections in which P acnes is involved.}, } @article {pmid27986898, year = {2017}, author = {Otsuka, T and Brauer, AL and Kirkham, C and Sully, EK and Pettigrew, MM and Kong, Y and Geller, BL and Murphy, TF}, title = {Antimicrobial activity of antisense peptide-peptide nucleic acid conjugates against non-typeable Haemophilus influenzae in planktonic and biofilm forms.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {72}, number = {1}, pages = {137-144}, pmid = {27986898}, issn = {1460-2091}, support = {R01 AI019641/AI/NIAID NIH HHS/United States ; R21 DC012917/DC/NIDCD NIH HHS/United States ; UL1 TR001412/TR/NCATS NIH HHS/United States ; UL1 TR001863/TR/NCATS NIH HHS/United States ; }, mesh = {Acyl Carrier Protein/*antagonists & inhibitors ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Haemophilus influenzae/*drug effects/physiology ; Microbial Sensitivity Tests ; Oligodeoxyribonucleotides, Antisense/*pharmacology ; Peptide Nucleic Acids/*pharmacology ; Serial Passage ; }, abstract = {BACKGROUND: Antisense peptide nucleic acids (PNAs) are synthetic polymers that mimic DNA/RNA and inhibit bacterial gene expression in a sequence-specific manner.

METHODS: To assess activity against non-typeable Haemophilus influenzae (NTHi), we designed six PNA-peptides that target acpP, encoding an acyl carrier protein. MICs and minimum biofilm eradication concentrations (MBECs) were determined. Resistant strains were selected by serial passages on media with a sub-MIC concentration of acpP-PNA.

RESULTS: The MICs of six acpP-PNA-peptides were 2.9-11 mg/L (0.63-2.5 μmol/L) for 20 clinical isolates, indicating susceptibility of planktonic NTHi. By contrast, MBECs were up to 179 mg/L (40 μmol/L). Compared with one original PNA-peptide (acpP-PNA1-3'N), an optimized PNA-peptide (acpP-PNA14-5'L) differs in PNA sequence and has a 5' membrane-penetrating peptide with a linker between the PNA and peptide. The optimized PNA-peptide had an MBEC ranging from 11 to 23 mg/L (2.5-5 μmol/L), indicating susceptibility. A resistant strain that was selected by the original acpP-PNA1-3'N had an SNP that introduced a stop codon in NTHI0044, which is predicted to encode an ATP-binding protein of a conserved ABC transporter. Deletion of NTHI0044 caused resistance to the original acpP-PNA1-3'N, but showed no effect on susceptibility to the optimized acpP-PNA14-5'L. The WT strain remained susceptible to the optimized PNA-peptide after 30 serial passages on media containing the optimized PNA-peptide.

CONCLUSIONS: A PNA-peptide that targets acpP, has a 5' membrane-penetrating peptide and has a linker shows excellent activity against planktonic and biofilm NTHi and is associated with a low risk for induction of resistance.}, } @article {pmid27986825, year = {2017}, author = {Syal, K and Bhardwaj, N and Chatterji, D}, title = {Vitamin C targets (p)ppGpp synthesis leading to stalling of long-term survival and biofilm formation in Mycobacterium smegmatis.}, journal = {FEMS microbiology letters}, volume = {364}, number = {1}, pages = {}, doi = {10.1093/femsle/fnw282}, pmid = {27986825}, issn = {1574-6968}, mesh = {Ascorbic Acid/metabolism/*pharmacology ; Biofilms/*growth & development ; Calorimetry ; Guanosine Pentaphosphate/*biosynthesis ; Kinetics ; Ligases/metabolism ; Microbial Viability/drug effects ; Mycobacterium smegmatis/drug effects/enzymology/*physiology ; Stress, Physiological/drug effects ; }, abstract = {Earlier, vitamin C was demonstrated to sterilize Mycobacterium tuberculosis culture via Fenton's reaction at high concentration. It alters the regulatory pathways associated with stress response and dormancy. Since (p)ppGpp is considered to be the master regulator of stress response and is responsible for bacterial survival under stress, we tested the effect of vitamin C on the formation of (p)ppGpp. In vivo estimation of (p)ppGpp showed a decrease in (p)ppGpp levels in vitamin C-treated M. smegmatis cells in comparison to the untreated cells. Furthermore, in vitro (p)ppGpp synthesis using RelMSM enzyme was conducted in order to confirm the specificity of the inhibition in the presence of variable concentrations of vitamin C. We observed that vitamin C at high concentration can inhibit the synthesis of (p)ppGpp. We illustrated binding of vitamin C to RelMSM by isothermal titration calorimetry. Enzyme kinetics was followed where K0.5 was found to be increased with the concomitant reduction of Vmax value suggesting mixed inhibition. Both long-term survival and biofilm formation were inhibited by vitamin C. The experiments suggest that vitamin C has the potential to be developed as the inhibitor of (p)ppGpp synthesis and stress response, at least in the concentration range used here.}, } @article {pmid27986718, year = {2017}, author = {Fritts, RK and LaSarre, B and Stoner, AM and Posto, AL and McKinlay, JB}, title = {A Rhizobiales-Specific Unipolar Polysaccharide Adhesin Contributes to Rhodopseudomonas palustris Biofilm Formation across Diverse Photoheterotrophic Conditions.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {4}, pages = {}, pmid = {27986718}, issn = {1098-5336}, mesh = {Adhesins, Bacterial/*genetics/*metabolism ; Bacterial Adhesion/*genetics/physiology ; Biofilms/*growth & development ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Multigene Family/genetics ; Polysaccharides, Bacterial/*genetics/*metabolism ; Rhodopseudomonas/genetics/*growth & development ; }, abstract = {UNLABELLED: Bacteria predominantly exist as members of surfaced-attached communities known as biofilms. Many bacterial species initiate biofilms and adhere to each other using cell surface adhesins. This is the case for numerous ecologically diverse Alphaprotebacteria, which use polar exopolysaccharide adhesins for cell-cell adhesion and surface attachment. Here, we show that Rhodopseudomonas palustris, a metabolically versatile member of the alphaproteobacterial order Rhizobiales, contains a functional unipolar polysaccharide (UPP) biosynthesis gene cluster. Deletion of genes predicted to be critical for UPP biosynthesis and export abolished UPP production. We also found that R. palustris uses UPP to mediate biofilm formation across diverse photoheterotrophic growth conditions, wherein light and organic substrates are used to support growth. However, UPP was less important for biofilm formation during photoautotrophy, where light and CO2 support growth, and during aerobic respiration with organic compounds. Expanding our analysis beyond R. palustris, we examined the phylogenetic distribution and genomic organization of UPP gene clusters among Rhizobiales species that inhabit diverse niches. Our analysis suggests that UPP is a conserved ancestral trait of the Rhizobiales but that it has been independently lost multiple times during the evolution of this clade, twice coinciding with adaptation to intracellular lifestyles within animal hosts.

IMPORTANCE: Bacteria are ubiquitously found as surface-attached communities and cellular aggregates in nature. Here, we address how bacterial adhesion is coordinated in response to diverse environments using two complementary approaches. First, we examined how Rhodopseudomonas palustris, one of the most metabolically versatile organisms ever described, varies its adhesion to surfaces in response to different environmental conditions. We identified critical genes for the production of a unipolar polysaccharide (UPP) and showed that UPP is important for adhesion when light and organic substrates are used for growth. Looking beyond R. palustris, we performed the most comprehensive survey to date on the conservation of UPP biosynthesis genes among a group of closely related bacteria that occupy diverse niches. Our findings suggest that UPP is important for free-living and plant-associated lifestyles but dispensable for animal pathogens. Additionally, we propose guidelines for classifying the adhesins produced by various Alphaprotebacteria, facilitating future functional and comparative studies.}, } @article {pmid27986717, year = {2017}, author = {Cheng, YY and Wu, C and Wu, JY and Jia, HL and Wang, MY and Wang, HY and Zou, SM and Sun, RR and Jia, R and Xiao, YZ}, title = {FlrA Represses Transcription of the Biofilm-Associated bpfA Operon in Shewanella putrefaciens.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {4}, pages = {}, pmid = {27986717}, issn = {1098-5336}, mesh = {Adhesins, Bacterial/*genetics/metabolism ; Bacterial Proteins/genetics ; Base Sequence ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/pharmacology ; Flagella/metabolism ; Gene Expression Regulation, Bacterial/genetics ; Promoter Regions, Genetic/genetics ; Repressor Proteins/*genetics ; Shewanella putrefaciens/genetics/*metabolism ; Transcription, Genetic/*genetics ; }, abstract = {UNLABELLED: Manipulation of biofilm formation in Shewanella is beneficial for application to industrial and environmental biotechnology. BpfA is an adhesin largely responsible for biofilm formation in many Shewanella species. However, the mechanism underlying BpfA production and the resulting biofilm remains vaguely understood. We previously described the finding that BpfA expression is enhanced by DosD, an oxygen-stimulated diguanylate cyclase, under aerobic growth. In the present work, we identify FlrA as a critical transcription regulator of the bpfA operon in Shewanella putrefaciens CN32 by transposon mutagenesis. FlrA acted as a repressor of the operon promoter by binding to two boxes overlapping the -10 and -35 sites recognized by σ[70] DosD regulation of the expression of the bpfA operon was mediated by FlrA, and cyclic diguanylic acid (c-di-GMP) abolished FlrA binding to the operon promoter. We also demonstrate that FlhG, an accessory protein for flagellum synthesis, antagonized FlrA repression of the expression of the bpfA operon. Collectively, this work demonstrates that FlrA acts as a central mediator in the signaling pathway from c-di-GMP to BpfA-associated biofilm formation in S. putrefaciens CN32.

IMPORTANCE: Motility and biofilm are mutually exclusive lifestyles, shifts between which are under the strict regulation of bacteria attempting to adapt to the fluctuation of diverse environmental conditions. The FlrA protein in many bacteria is known to control motility as a master regulator of flagellum synthesis. This work elucidates its effect on biofilm formation by controlling the expression of the adhesin BpfA in S. putrefaciens CN32 in response to c-di-GMP. Therefore, FlrA plays a dual role in controlling motility and biofilm formation in S. putrefaciens CN32. The cooccurrence of flrA, bpfA, and the FlrA box in the promoter region of the bpfA operon in diverse Shewanella strains suggests that bpfA is a common mechanism that controls biofilm formation in this bacterial species.}, } @article {pmid27983816, year = {2017}, author = {Xie, GJ and Cai, C and Hu, S and Yuan, Z}, title = {Complete Nitrogen Removal from Synthetic Anaerobic Sludge Digestion Liquor through Integrating Anammox and Denitrifying Anaerobic Methane Oxidation in a Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {51}, number = {2}, pages = {819-827}, doi = {10.1021/acs.est.6b04500}, pmid = {27983816}, issn = {1520-5851}, mesh = {Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; Denitrification ; In Situ Hybridization, Fluorescence ; *Methane ; Nitrogen ; Oxidation-Reduction ; *Sewage ; }, abstract = {Partial nitritation and Anammox processes are increasingly used for nitrogen removal from anaerobic sludge digestion liquor. However, their nitrogen removal efficiency is often limited due to the production of nitrate by the Anammox reaction and the sensitivity to the nitrite to ammonium ratio. This work develops and demonstrates an innovative process that achieves complete nitrogen removal from partially nitrified anaerobic sludge digestion liquor through the use of a membrane biofilm reactor (MBfR), with methane supplied through hollow fiber membranes. When steady state with a hydraulic retention time (HRT) of 1 day was reached, the process achieved complete nitrite and ammonium removal at rates of 560 mg N/L/d and 470 mg N/L/d, respectively, without any nitrate accumulation. The process is relatively insensitive to the nitrite to ammonium ratio, achieving complete nitrogen removal when their ratio in influent varied in the range of 1.125-1.32. Pyrosequencing and fluorescence in situ hybridization analysis revealed that denitrifying anaerobic methane oxidation (DAMO) archaea, Anammox bacteria and DAMO bacteria jointly dominated the microbial community. Mass balance analysis showed that nitrate produced by Anammox (122.2 mg N/L/d) was entirely converted to nitrite by DAMO archaea, while nitrite in the feed and produced by DAMO archaea was jointly removed by Anammox (90%) and DAMO bacteria (10%). The nitrogen removal rate of over 1 kg N/m[3]/d is comparable to the practical rates reported for side-stream nitrogen removal processes.}, } @article {pmid27982704, year = {2016}, author = {Kathwate, GH and Karuppayil, SM}, title = {Tramadol, an Opioid Receptor Agonist: An Inhibitor of Growth, Morphogenesis, and Biofilm Formation in the Human Pathogen, Candida albicans.}, journal = {Assay and drug development technologies}, volume = {14}, number = {10}, pages = {567-572}, doi = {10.1089/adt.2016.760}, pmid = {27982704}, issn = {1557-8127}, mesh = {Analgesics, Opioid/*pharmacology ; Antifungal Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Humans ; Microbial Sensitivity Tests/methods ; Morphogenesis/*drug effects/physiology ; Tramadol/*pharmacology ; }, abstract = {Tramadol is a synthetic, centrally acting low-affinity agonist of μ-opioid receptors in humans. It is used as an analgesic and is shown to have local anesthetic action. In this study, we have tried to explore its anti-Candida potential. Minimum inhibitory concentration (MIC50) and minimum fungicidal concentration (MFC) values were established. MIC50 ranged from 2 to 4 mg/mL, whereas MFC was recorded at 8 mg/mL. Also, the effect of tramadol on germ tube formation, adhesion, and biofilms in Candida albicans was studied. Tramadol impaired in vitro growth of C. albicans. A time-dependent killing assay showed that it kills C. albicans within 24 h of exposure. Tramadol has strong activity against Candida virulence factors such as yeast-to-hyphal form switching and adhesion. C. albicans biofilms, which are notoriously resistant to many antifungals, were sensitive to tramadol. At 8 mg/mL of tramadol, 82% of early stage biofilms and 52.88% of matured biofilms were inhibited. Although our results show that the antifungal effect of tramadol requires concentrations that can be achieved only locally, they may provide potential candidates for development of novel antifungal drugs.}, } @article {pmid27982182, year = {2016}, author = {Peracini, A and Regis, RR and Souza, RF and Pagnano, VO and Silva, CH and Paranhos, HF}, title = {Alkaline Peroxides Versus Sodium Hypochlorite for Removing Denture Biofilm: a Crossover Randomized Trial.}, journal = {Brazilian dental journal}, volume = {27}, number = {6}, pages = {700-704}, doi = {10.1590/0103-6440201600913}, pmid = {27982182}, issn = {1806-4760}, mesh = {*Biofilms ; Cross-Over Studies ; Dentures/*microbiology ; Female ; Humans ; Male ; Peroxides/*administration & dosage ; Sodium Hypochlorite/*administration & dosage ; }, abstract = {This study evaluated the efficacy of cleanser solutions on denture biofilm removal by a crossover randomized clinical trial. Thirty two edentulous patients were instructed to brush their dentures (specific brush and liquid soap) three times a day (after breakfast, lunch and dinner) and to soak them (≥ 8 h) in: (C) control -water; (AP): alkaline peroxide; or (SH) 0.5% sodium hypochlorite. Each solution was used for 21 days (three cycles of 7 days). At the end of each cycle, the inner surfaces of maxillary dentures were disclosed (1% neutral red) and photographed (HX1 - Sony). Areas (total and stained biofilm) were measured (Image Tool software) and the percentage of biofilm calculated as the ratio between the area of the biofilm multiplied by 100 and total surface area of the internal base of the denture. Data were compared by means of generalized estimating equation (α=5%) and multiple comparisons (Bonferroni; α=1.67%). Immersion in SH reduced biofilm (%) (8.3 ± 13.3B) compared to C (18.2 ± 14.9A) and AP (18.2 ± 16.6A). The 0.5% sodium hypochlorite solution was the most efficacious for biofilm removal. Alkaline peroxides may not lead to further biofilm removal in patients with adequate denture maintenance habits.}, } @article {pmid27982179, year = {2016}, author = {Fúcio, SB and Paula, AB and Sardi, JC and Duque, C and Correr-Sobrinho, L and Puppin-Rontani, RM}, title = {Streptococcus Mutans Biofilm Influences on the Antimicrobial Properties of Glass Ionomer Cements.}, journal = {Brazilian dental journal}, volume = {27}, number = {6}, pages = {681-687}, doi = {10.1590/0103-6440201600655}, pmid = {27982179}, issn = {1806-4760}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Culture Media ; Glass Ionomer Cements/*pharmacology ; Streptococcus mutans/*drug effects ; }, abstract = {The aim of this study was to evaluate the in vitro antibacterial and biofilm inhibition properties of glass ionomer restorative cements. Ketac Nano, Vitremer, Ketac Molar Easymix and Fuji IX were analyzed using the following tests: a) agar plate diffusion test to evaluate the inhibitory activity of cements against S. mutans (n=8); b) S. mutans adherence test by counting colony-forming units after 2 h of material/bacteria exposure (n=10); c) biofilm wet weight after seven days of bacterial accumulation on material disks, with growth medium renewed every 48 h (n=10); d) pH and fluoride measurements from the medium aspired at 48 h intervals during the 7-day biofilm development (n=10). Data from the a, b and c tests were submitted to Kruskal-Wallis and Mann-Whitney tests and the fluoride-release and pH data were submitted to two-way ANOVA and Tukey tests (a=5%). Vitremer followed by Ketac Nano showed the greatest inhibitory zone against S. mutans than the conventional ionomers. Vitremer also showed higher pH values than Ketac Nano and Fuji IX in the first 48 h and released higher fluoride amount than Ketac Nano e Ketac Molar Easymix throughout the experimental period. The chemical composition of restorative glass ionomer materials influenced the antibacterial properties. The resin modified glass ionomer (Vitremer) was more effective for inhibition of S. mutans and allowed greater neutralization of the pH in the first 48 h. However, the type of glass ionomer (resin modified or conventional) did not influence the weight and adherence of the biofilm and fluoride release.}, } @article {pmid27980856, year = {2016}, author = {Sapi, E and Theophilus, PA and Pham, TV and Burugu, D and Luecke, DF}, title = {Effect of RpoN, RpoS and LuxS Pathways on the Biofilm Formation and Antibiotic Sensitivity of Borrelia Burgdorferi.}, journal = {European journal of microbiology & immunology}, volume = {6}, number = {4}, pages = {272-286}, pmid = {27980856}, issn = {2062-509X}, abstract = {Borrelia burgdorferi, the causative agent of Lyme disease, is capable of forming biofilm in vivo and in vitro, a structure well known for its resistance to antimicrobial agents. For the formation of biofilm, signaling processes are required to communicate with the surrounding environment such as it was shown for the RpoN-RpoS alternative sigma factor and for the LuxS quorum-sensing pathways. Therefore, in this study, the wild-type B. burgdorferi and different mutant strains lacking RpoN, RpoS, and LuxS genes were studied for their growth characteristic and development of biofilm structures and markers as well as for their antibiotic sensitivity. Our results showed that all three mutants formed small, loosely formed aggregates, which expressed previously identified Borrelia biofilm markers such as alginate, extracellular DNA, and calcium. All three mutants had significantly different sensitivity to doxycyline in the early log phase spirochete cultures; however, in the biofilm rich stationary cultures, only LuxS mutant showed increased sensitivity to doxycyline compared to the wild-type strain. Our findings indicate that all three mutants have some effect on Borrelia biofilm, but the most dramatic effect was found with LuxS mutant, suggesting that the quorum-sensing pathway plays an important role of Borrelia biofilm formation and antibiotic sensitivity.}, } @article {pmid27979700, year = {2017}, author = {Zhang, D and Li, Z and Zhang, C and Zhou, X and Xiao, Z and Awata, T and Katayama, A}, title = {Phenol-degrading anode biofilm with high coulombic efficiency in graphite electrodes microbial fuel cell.}, journal = {Journal of bioscience and bioengineering}, volume = {123}, number = {3}, pages = {364-369}, doi = {10.1016/j.jbiosc.2016.10.010}, pmid = {27979700}, issn = {1347-4421}, mesh = {Anaerobiosis ; *Bioelectric Energy Sources ; *Biofilms ; Catalysis ; Electricity ; Electrodes ; Geobacter/genetics/metabolism ; Graphite/*metabolism ; Oxidation-Reduction ; Phenol/*metabolism ; RNA, Ribosomal, 16S/genetics ; }, abstract = {A microbial fuel cell (MFC), with graphite electrodes as both the anode and cathode, was operated with a soil-free anaerobic consortium for phenol degradation. This phenol-degrading MFC showed high efficiency with a current density of 120 mA/m[2] and a coulombic efficiency of 22.7%, despite the lack of a platinum catalyst cathode and inoculation of sediment/soil. Removal of planktonic bacteria by renewing the anaerobic medium did not decrease the performance, suggesting that the phenol-degrading MFC was not maintained by the planktonic bacteria but by the microorganisms in the anode biofilm. Cyclic voltammetry analysis of the anode biofilm showed distinct oxidation and reduction peaks. Analysis of the microbial community structure of the anode biofilm and the planktonic bacteria based on 16S rRNA gene sequences suggested that Geobacter sp. was the phenol degrader in the anode biofilm and was responsible for current generation.}, } @article {pmid27978439, year = {2017}, author = {Bian, W and Zhang, S and Zhang, Y and Li, W and Kan, R and Wang, W and Zheng, Z and Li, J}, title = {Achieving nitritation in a continuous moving bed biofilm reactor at different temperatures through ratio control.}, journal = {Bioresource technology}, volume = {226}, number = {}, pages = {73-79}, doi = {10.1016/j.biortech.2016.12.014}, pmid = {27978439}, issn = {1873-2976}, mesh = {Ammonia/metabolism ; Biofilms ; *Bioreactors ; Equipment Design ; Nitrites/analysis ; Nitrogen/metabolism ; Oxygen/metabolism ; Temperature ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater/chemistry ; }, abstract = {A ratio control strategy was implemented in a continuous moving bed biofilm reactor (MBBR) to investigate the response to different temperatures. The control strategy was designed to maintain a constant ratio between dissolved oxygen (DO) and total ammonia nitrogen (TAN) concentrations. The results revealed that a stable nitritation in a biofilm reactor could be achieved via ratio control, which compensated the negative influence of low temperatures by stronger oxygen-limiting conditions. Even with a temperature as low as 6°C, stable nitritation could be achieved when the controlling ratio did not exceed 0.17. Oxygen-limiting conditions in the biofilm reactor were determined by the DO/TAN concentrations ratio, instead of the mere DO concentration. This ratio control strategy allowed the achievement of stable nitritation without complete wash-out of NOB from the reactor. Through the ratio control strategy full nitritation of sidestream wastewater was allowed; however, for mainstream wastewater, only partial nitritation was recommended.}, } @article {pmid27976869, year = {2017}, author = {Liu, C and Faria, AF and Ma, J and Elimelech, M}, title = {Mitigation of Biofilm Development on Thin-Film Composite Membranes Functionalized with Zwitterionic Polymers and Silver Nanoparticles.}, journal = {Environmental science & technology}, volume = {51}, number = {1}, pages = {182-191}, doi = {10.1021/acs.est.6b03795}, pmid = {27976869}, issn = {1520-5851}, mesh = {Biofilms ; Biofouling ; Nanoparticles ; *Polymers ; *Silver ; }, abstract = {We demonstrate the functionalization of thin-film composite membranes with zwitterionic polymers and silver nanoparticles (AgNPs) for combating biofouling. Combining hydrophilic zwitterionic polymer brushes and biocidal AgNPs endows the membrane with dual functionality: antiadhesion and bacterial inactivation. An atom transfer radical polymerization (ATRP) reaction is used to graft zwitterionic poly(sulfobetaine methacrylate) (PSBMA) brushes to the membrane surface, while AgNPs are synthesized in situ through chemical reduction of silver. Two different membrane architectures (Ag-PSBMA and PSBMA-Ag TFC) are developed according to the sequence AgNPs, and PSBMA brushes are grafted on the membrane surface. A static adhesion assay shows that both modified membranes significantly reduced the adsorption of proteins, which served as a model organic foulant. However, improved antimicrobial activity is observed for PSBMA-Ag TFC (i.e., AgNPs on top of the polymer brush) in comparison to the Ag-PSBMA TFC membrane (i.e., polymer brush on top of AgNPs), indicating that architecture of the antifouling layer is an important factor in the design of zwitterion-silver membranes. Confocal laser scanning microscopy (CLSM) imaging indicated that PSBMA-Ag TFC membranes effectively inhibit biofilm formation under dynamic cross-flow membrane biofouling tests. Finally, we demonstrate the regeneration of AgNPs on the membrane after depletion of silver from the surface of the PSBMA-Ag TFC membrane.}, } @article {pmid27974249, year = {2017}, author = {Miller, HC and Morgan, MJ and Wylie, JT and Kaksonen, AH and Sutton, D and Braun, K and Puzon, GJ}, title = {Elimination of Naegleria fowleri from bulk water and biofilm in an operational drinking water distribution system.}, journal = {Water research}, volume = {110}, number = {}, pages = {15-26}, doi = {10.1016/j.watres.2016.11.061}, pmid = {27974249}, issn = {1879-2448}, mesh = {Biofilms ; Disinfectants ; *Drinking Water ; Halogenation ; *Naegleria fowleri ; }, abstract = {Global incidence of primary amoebic meningoencephalitis cases associated with domestic drinking water is increasing. The need for understanding disinfectant regimes capable of eliminating the causative microorganism, Naegleria fowleri, from bulk water and pipe wall biofilms is critical. This field study demonstrated the successful elimination of N. fowleri from the bulk water and pipe wall biofilm of a persistently colonised operational drinking water distribution system (DWDS), and the prevention of further re-colonisation. A new chlorination unit was installed along the pipe line to boost the free chlorine residual to combat the persistence of N. fowleri. Biofilm and bulk water were monitored prior to and after re-chlorination (RCl), pre-rechlorination (pre-RCl) and post-rechlorination (post-RCl), respectively, for one year. A constant free chlorine concentration of > 1 mg/L resulted in the elimination of N. fowleri from both the bulk water and biofilm at the post-RCl site. Other amoeba species were detected during the first two months of chlorination, but all amoebae were eliminated from both the bulk water and biofilm at post-RCl after 60 days of chlorination with free chlorine concentrations > 1 mg/L. In addition, a dynamic change in the biofilm community composition and a four log reduction in biofilm cell density occurred post-RCl. The pre-RCl site continued to be seasonally colonised by N. fowleri, but the constant free chlorine residual of > 1 mg/L prevented N. fowleri from recolonising the bulk and pipe wall biofilm at the post-RCl site. To our knowledge, this is the first study to demonstrate successful removal of N. fowleri from both the bulk and pipe wall biofilm and prevention of re-colonisation of N. fowleri in an operational DWDS. The findings of this study are of importance to water utilities in addressing the presence of N. fowleri and other amoeba in susceptible DWDSs.}, } @article {pmid27974013, year = {2016}, author = {Edmiston, CE and McBain, AJ and Kiernan, M and Leaper, DJ}, title = {A narrative review of microbial biofilm in postoperative surgical site infections: clinical presentation and treatment.}, journal = {Journal of wound care}, volume = {25}, number = {12}, pages = {693-702}, doi = {10.12968/jowc.2016.25.12.693}, pmid = {27974013}, issn = {0969-0700}, mesh = {Anti-Infective Agents/therapeutic use ; *Biofilms ; Humans ; Prosthesis-Related Infections/diagnosis/microbiology/therapy ; Risk Factors ; Surgical Wound Infection/*diagnosis/*microbiology/*therapy ; Wound Healing ; }, abstract = {OBJECTIVE: The global impact of surgical site infections (SSIs) on health-care systems is considerable: many are related to the formation of a microbial biofilm. Biofilm plays a significant role in the pathogenesis of implantable device-related infections and are also important in persistent postoperative skin and soft tissue wound infections.

METHOD: PubMed and OVID databases were searched for relevant articles regarding biofilm-associated infection in surgery, including epidemiology, diagnosis, treatment and management.

RESULTS: Biofilm-associated infections increase the use of health-care resources, prolong length of stay, increase cost of antibiotic therapy, result in additional surgical revisions and extend rehabilitation after discharge from health care. Staphylococcus aureus and Staphylococcus epidermidis are the most common isolates recovered from device-related infections. Early infection occurs within two weeks of implantation and is associated with intraoperative wound contamination; late-onset infections are often occult prolonging recognition by weeks, months and in some cases, years. Biofilm is a physical barrier against antibodies and granulocytic cell populations which may also impede the penetration of antibiotics. The ideal strategy for preventing biofilm-associated SSI is to prevent intraoperative contamination through compliance with effective surgical care bundles. Management of postoperative biofilm-associated infections involves surgical debridement followed by irrigation with antimicrobial agents and removal of infected devices, followed by insertion of antimicrobial adjuncts such as antimicrobial spacers, beads or sutures together with selective therapeutic agents that penetrate the mature biofilm.

CONCLUSION: Biofilm-associated infections are a significant source of postoperative morbidity and mortality. Appropriate interventional strategies are warranted to reduce the risk of intraoperative contamination.

DECLARATION OF INTEREST: The authors have no conflicts.}, } @article {pmid27973371, year = {2016}, author = {Sarti, A and Lamon, AW and Ono, A and Foresti, E}, title = {A new device to select carriers for biomass immobilization and application in an aerobic/anaerobic fixed-bed sequencing batch biofilm reactor for nitrogen removal.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {11}, pages = {2666-2674}, doi = {10.2166/wst.2016.410}, pmid = {27973371}, issn = {0273-1223}, mesh = {Ammonia/metabolism ; *Biofilms ; Biomass ; *Bioreactors ; Coal ; Denitrification ; Nitrification ; Nitrites/metabolism ; Nitrogen/*metabolism ; Oxygen ; Polyethylene ; Polyurethanes ; Waste Disposal, Fluid/methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {This study proposes a new approach to selecting a biofilm carrier for immobilization using dissolved oxygen (DO) microsensors to measure the thickness of aerobic and anaerobic layers in biofilm. The biofilm carriers tested were polyurethane foam, mineral coal (MC), basaltic gravel, and low-density polyethylene. Development of layers in the biofilm carrier surface was evaluated using a flow cell device, and DO profiles were conducted to determine the size of the layers (aerobic and anaerobic). MC was the biofilm carrier selected due to allowing the development of larger aerobic and anaerobic layers in the biofilm (896 and 1,058 μm, respectively). This ability is supposed to improve simultaneous nitrogen removal by nitrification and denitrification biological processes. Thus, as a biofilm carrier, MC was used in a fixed-bed sequencing batch biofilm reactor (FB-SBBR) for treatment of wastewater with a high ammonia concentration (100-400 mgNH4[+]-N L[-1]). The FB-SBBR (15.0 L) was filled with matrices of the carrier and operated under alternating aeration and non-aeration periods of 6 h each. At a mean nitrogen loading rate of 0.55 ± 0.10 kgNH4[+]-N m[-3] d[-1], the reactor attained a mean nitrification efficiency of 95 ± 9% with nitrite as the main product (aerobic period). Mean denitrification efficiency during the anoxic period was 72 ± 13%.}, } @article {pmid27966513, year = {2016}, author = {Sethi, KS and Karde, PA and Joshi, CP}, title = {Comparative evaluation of sutures coated with triclosan and chlorhexidine for oral biofilm inhibition potential and antimicrobial activity against periodontal pathogens: An in vitro study.}, journal = {Indian journal of dental research : official publication of Indian Society for Dental Research}, volume = {27}, number = {5}, pages = {535-539}, doi = {10.4103/0970-9290.195644}, pmid = {27966513}, issn = {1998-3603}, mesh = {Anti-Infective Agents, Local/*therapeutic use ; Biofilms/*drug effects ; Chlorhexidine/*therapeutic use ; Humans ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Periodontitis/microbiology/prevention & control ; *Sutures/microbiology ; Triclosan/*therapeutic use ; }, abstract = {BACKGROUND: Surgical site plaque accumulation is one of the challenging problems leading to unfavorable healing. The antibacterial sutures can be used to reduce or inhibit plaque formation. Presently there is no study comparing efficacy of sutures coated with triclosan and chlorhexidine in terms of oral biofilm inhibition and antimicrobial property against periodontal pathogens.

AIM: The aim of present study was to evaluate the antibacterial efficacy and oral biofilm inhibition around chlorhexidine and triclosan coated polyglactin sutures in comparison to uncoated sutures.

MATERIALS AND METHOD: Equal segments of chlorhexidine and triclosan coated polyglactin sutures (3-0) were incubated at 370°C in saliva collected from 10 chronic periodontitis patients for 7 days. Plain uncoated suture served as control. Biofilm formation was analyzed with Confocal Laser-Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). Quantitative assessment was done using Colony Forming Units (CFU/mL).The antibacterial efficacy of the sutures was tested against specific periodontal pathogens (S.mutans, F.nucleatum, A.actinomycetomcomitans, P.intermedia, P.gingivalis) using agar diffusion method. CLSM and SEM were not subjected to statistical analysis. ANOVA test was used for colony forming units and agar diffusion test. (P < 0.05) Results: CLSM and SEM showed substantial biofilm inhibition around chlorhexidine-coated sutures followed by triclosan-coated when compared to plain uncoated suture. The antibacterial coated sutures showed statistically significant difference in CFUs/ml and zone of inhibition compared to plain uncoated sutures. Among coated sutures, chlorhexidine-coated sutures showed better results.

CONCLUSION: The antibacterial coated sutures have a promising potential in preventing the colonization of periodontal pathogens around it thereby inhibiting biofilm formation.}, } @article {pmid27965730, year = {2016}, author = {Greener, J and Parvinzadeh Gashti, M and Eslami, A and Zarabadi, MP and Taghavi, SM}, title = {A microfluidic method and custom model for continuous, non-intrusive biofilm viscosity measurements under different nutrient conditions.}, journal = {Biomicrofluidics}, volume = {10}, number = {6}, pages = {064107}, pmid = {27965730}, issn = {1932-1058}, abstract = {Straight, low-aspect ratio micro flow cells are used to support biofilm attachment and preferential accumulation at the short side-wall, which progressively reduces the effective channel width. The biofilm shifts downstream at measurable velocities under the imposed force from the constant laminar co-flowing nutrient stream. The dynamic behaviour of the biofilm viscosity is modeled semi-analytically, based on experimental measurements of biofilm dimensions and velocity as inputs. The technique advances the study of biofilm mechanical properties by strongly limiting biases related to non-Newtonian biofilm properties (e.g., shear dependent viscosity) with excellent time resolution. To demonstrate the proof of principle, young Pseudomonas sp. biofilms were analyzed under different nutrient concentrations and constant micro-flow conditions. The striking results show that large initial differences in biofilm viscosities grown under different nutrient concentrations become nearly identical in less than one day, followed by a continuous thickening process. The technique verifies that in 50 h from inoculation to early maturation stages, biofilm viscosity could grow by over 2 orders of magnitude. The approach opens the way for detailed studies of mechanical properties under a wide variety of physiochemical conditions, such as ionic strength, temperature, and shear stress.}, } @article {pmid27960182, year = {2017}, author = {Schlafer, S and Ibsen, CJ and Birkedal, H and Nyvad, B}, title = {Calcium-Phosphate-Osteopontin Particles Reduce Biofilm Formation and pH Drops in in situ Grown Dental Biofilms.}, journal = {Caries research}, volume = {51}, number = {1}, pages = {26-33}, doi = {10.1159/000451064}, pmid = {27960182}, issn = {1421-976X}, mesh = {Adult ; Animals ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Calcium Phosphates/*pharmacology ; Cattle ; Cross-Over Studies ; Dental Caries/*microbiology ; Glucose/pharmacology ; Humans ; Hydrogen-Ion Concentration ; Microbial Viability/drug effects ; Microscopy, Confocal ; Milk/chemistry ; Osteopontin/*pharmacology ; Sodium Chloride/pharmacology ; Time Factors ; }, abstract = {This 2-period crossover study investigated the effect of calcium-phosphate-osteopontin particles on biofilm formation and pH in 48-h biofilms grown in situ. Bovine milk osteopontin is a highly phosphorylated glycoprotein that has been shown to interfere with bacterial adhesion to salivary-coated surfaces. Calcium-phosphate-osteopontin particles have been shown to reduce biofilm formation and pH drops in a 5-species laboratory model of dental biofilm without affecting bacterial viability. Here, smooth surface biofilms from 10 individuals were treated ex vivo 6 times/day for 30 min with either calcium-phosphate-osteopontin particles or sterile saline. After growth, the amount of biofilm formed was determined by confocal microscopy, and pH drops upon exposure to glucose were monitored using confocal-microscopy-based pH ratiometry. A total of 160 biofilms were analysed. No adverse effects of repeated ex vivo treatment with calcium-phosphate-osteopontin particles were observed. Particle treatment resulted in a 32% lower amount of biofilm formed (p < 0.05), but large inter-individual differences could be observed. Biofilm pH was significantly higher upon particle treatment, both shortly after the addition of glucose and after 30 min of incubation with glucose (p < 0.05). Calcium-phosphate-osteopontin particles may represent a new therapeutic approach to caries control and aim at directly targeting virulence factors involved in the caries process. Further studies are required to determine the effect of particle treatment on more acidogenic/aciduric biofilms as well as the remineralizing potential of the particles.}, } @article {pmid27959542, year = {2017}, author = {Wang, H and Wilksch, JJ and Chen, L and Tan, JW and Strugnell, RA and Gee, ML}, title = {Influence of Fimbriae on Bacterial Adhesion and Viscoelasticity and Correlations of the Two Properties with Biofilm Formation.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {33}, number = {1}, pages = {100-106}, doi = {10.1021/acs.langmuir.6b03764}, pmid = {27959542}, issn = {1520-5827}, abstract = {The surface polymers of bacteria determine the ability of bacteria to adhere to a substrate for colonization, which is an essential step for a variety of microbial processes, such as biofilm formation and biofouling. Capsular polysaccharides and fimbriae are two major components on a bacterial surface, which are critical for mediating cell-surface interactions. Adhesion and viscoelasticity of bacteria are two major physical properties related to bacteria-surface interactions. In this study, we employed atomic force microscopy (AFM) to interrogate how the adhesion work and the viscoelasticity of a bacterial pathogen, Klebsiella pneumoniae, influence biofilm formation. To do this, the wild-type, type 3 fimbriae-deficient, and type 3 fimbriae-overexpressed K. pneumoniae strains have been investigated in an aqueous environment. The results show that the measured adhesion work is positively correlated to biofilm formation; however, the viscoelasticity is not correlated to biofilm formation. This study indicates that AFM-based adhesion measurements of bacteria can be used to evaluate the function of bacterial surface polymers in biofilm formation and to predict the ability of bacterial biofilm formation.}, } @article {pmid27958773, year = {2017}, author = {Abinaya Sindu, P and Gautam, P}, title = {Studies on the biofilm produced by Pseudomonas aeruginosa grown in different metal fatty acid salt media and its application in biodegradation of fatty acids and bioremediation of heavy metal ions.}, journal = {Canadian journal of microbiology}, volume = {63}, number = {1}, pages = {61-73}, doi = {10.1139/cjm-2015-0384}, pmid = {27958773}, issn = {1480-3275}, mesh = {Biodegradation, Environmental ; *Biofilms/growth & development ; Copper/metabolism ; Culture Media/chemistry/metabolism ; Fatty Acids/metabolism ; Ions/metabolism ; Metals, Heavy/*metabolism ; Plankton/growth & development/physiology ; Pseudomonas aeruginosa/growth & development/*physiology ; Sodium Chloride/metabolism ; Spectroscopy, Fourier Transform Infrared ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Metal fatty acid salts (MFAS) in untreated industrial effluents cause environmental pollution. The use of biocompatible agents for remediation may help in reducing the harm caused to the ambient aquatic organism. Pseudomonas aeruginosa is a ubiquitous organism that thrives under harsh conditions and is resistant to toxic metal ions. The present study shows a proof-of-concept of using this organism in the biodegradation of MFAS. MFAS were prepared and we studied their effect on the growth of the planktonic form and the formation of biofilm by P. aeruginosa. We observed biofilm formation in the presence of all the MFAS when used as the sole carbon source, albeit the quantity of biofilm formed in the presence of cadmium and copper was less. There was no effect on the planktonic form of the organism but the formation of biofilm increased in the presence of magnesium palmitate. This study shows that metal ions play a pivotal role in the formation of biofilm. HPLC (high-performance liquid chromatography) analysis of the biofilm polysaccharide showed that hexose sugar was a major component when compared with pentose sugar. The structure of biofilm polysaccharide and the coordination of the metal ion with the biofilm polysaccharide were confirmed by FTIR (Fourier transform infrared spectroscopy) and Raman spectroscopy.}, } @article {pmid27957853, year = {2017}, author = {Bhagirath, AY and Pydi, SP and Li, Y and Lin, C and Kong, W and Chelikani, P and Duan, K}, title = {Characterization of the Direct Interaction between Hybrid Sensor Kinases PA1611 and RetS That Controls Biofilm Formation and the Type III Secretion System in Pseudomonas aeruginosa.}, journal = {ACS infectious diseases}, volume = {3}, number = {2}, pages = {162-175}, doi = {10.1021/acsinfecdis.6b00153}, pmid = {27957853}, issn = {2373-8227}, mesh = {Amino Acid Substitution ; Bacterial Proteins/chemistry/*metabolism ; Binding Sites ; Biofilms ; Gene Expression Regulation, Bacterial ; Histidine Kinase/chemistry/genetics/*metabolism ; Models, Molecular ; Mutagenesis, Site-Directed ; Protein Binding ; Protein Domains ; Pseudomonas aeruginosa/chemistry/metabolism/*physiology ; Two-Hybrid System Techniques ; Type III Secretion Systems/*metabolism ; }, abstract = {One of the leading causes of morbidity and mortality in cystic fibrosis (CF) patients is pulmonary infection with Pseudomonas aeruginosa, and the pathophysiology of pulmonary infection in CF is affected by the lifestyle of this micro-organism. RetS-GacS/A-RsmA is a key regulatory pathway in P. aeruginosa that determines the bacterium's lifestyle choice. Previously, we identified PA1611, a hybrid sensor kinase, as a new player in this pathway that interacts with RetS and influences biofilm formation and type III secretion system. In this study, we explored the structural and mechanistic basis of the interaction between PA1611 and RetS. We identified the amino acid residues critical for PA1611-RetS interactions by molecular modeling. These residues were then targeted for site-directed mutagenesis. Amino acid substitutions were carried out at seven key positions in PA1611 and at six corresponding key positions in RetS. The influence of such substitutions in PA1611 on the interaction was analyzed by bacterial two-hybrid assays. We carried out functional analysis of these mutants in P. aeruginosa for their effect on specific phenotypes. Two residues, F269 and E276, located within the histidine kinase A and histidine kinase-like ATPase domains of PA1611 were found to play crucial roles in the PA1611-RetS interaction and had profound effects on phenotypes. Corresponding mutations in RetS demonstrated similar results. We further confirmed that these mutations in PA1611 function through the GacS/GacA-RsmY/Z signaling pathway. Collectively, our findings provide a noncognate sensor kinase direct interaction model for a signaling pathway, key for lifestyle selection in P. aeruginosa, and targeting such interaction may serve as a novel way of controlling infections with P. aeruginosa.}, } @article {pmid27957257, year = {2016}, author = {Frough-Reyhani, M and Ghasemi, N and Soroush-Barhaghi, M and Amini, M and Gholizadeh, Y}, title = {Antimicrobial efficacy of different concentration of sodium hypochlorite on the biofilm of Enterococcus faecalis at different stages of development.}, journal = {Journal of clinical and experimental dentistry}, volume = {8}, number = {5}, pages = {e480-e484}, pmid = {27957257}, issn = {1989-5488}, abstract = {BACKGROUND: Persistent infection of the root canal due to the presence of resistance bacterial species, such as Enterococcus faecalis, has always been one of the most important reasons for endodontic treatment failure. This study investigated the antimicrobial efficacy of 1%, 2.5 % and 5% sodium hypochlorite in eliminating E. faecalis biofilms at different stages of development.

MATERIAL AND METHODS: In this study 4-, 6- and 10-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS) or 1%, 2.5% and 5% NaOCl. Dentin chip suspensions were used for colony forming unit (CFU) counting to estimate remaining E. faecalis counts. Statistical comparison of the means was carried out with Kruskal-Wallis test, and pair-wise comparisons were made by Mann-Whitney U test, at a significance level of P<0.05.

RESULTS: The results showed that 2.5% and 5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 85.73%, 81.88% and 78.62% decreases in bacterial counts in 4-, 6- and 10-week-old biofilms, respectively, which was significantly more than those with PBS (p<0.05).

CONCLUSIONS: The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival rate and residual bacteria increased with biofilm aging. Key words:Antibacterial, biofilm, E. faecalis, sodium hypochlorite.}, } @article {pmid27956524, year = {2017}, author = {Plumley, BA and Martin, KH and Borlee, GI and Marlenee, NL and Burtnick, MN and Brett, PJ and AuCoin, DP and Bowen, RA and Schweizer, HP and Borlee, BR}, title = {Thermoregulation of Biofilm Formation in Burkholderia pseudomallei Is Disrupted by Mutation of a Putative Diguanylate Cyclase.}, journal = {Journal of bacteriology}, volume = {199}, number = {5}, pages = {}, pmid = {27956524}, issn = {1098-5530}, support = {U54 AI065357/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Burkholderia pseudomallei/*physiology ; Computational Biology ; Cyclic GMP/analogs & derivatives/metabolism ; DNA Transposable Elements ; Databases, Factual ; Escherichia coli Proteins/genetics/*metabolism ; Evolution, Molecular ; Gene Expression Regulation, Bacterial/*physiology ; Gene Expression Regulation, Enzymologic/physiology ; Mutation ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; *Temperature ; }, abstract = {Burkholderia pseudomallei, a tier 1 select agent and the etiological agent of melioidosis, transitions from soil and aquatic environments to infect a variety of vertebrate and invertebrate hosts. During the transition from an environmental saprophyte to a mammalian pathogen, B. pseudomallei encounters and responds to rapidly changing environmental conditions. Environmental sensing systems that control cellular levels of cyclic di-GMP promote pathogen survival in diverse environments. Cyclic di-GMP controls biofilm production, virulence factors, and motility in many bacteria. This study is an evaluation of cyclic di-GMP-associated genes that are predicted to metabolize and interact with cyclic di-GMP as identified from the annotated genome of B. pseudomallei 1026b. Mutants containing transposon disruptions in each of these genes were characterized for biofilm formation and motility at two temperatures that reflect conditions that the bacteria encounter in the environment and during the infection of a mammalian host. Mutants with transposon insertions in a known phosphodiesterase (cdpA) and a predicted hydrolase (Bp1026b_I2285) gene exhibited decreased motility regardless of temperature. In contrast, the phenotypes exhibited by mutants with transposon insertion mutations in a predicted diguanylate cyclase gene (Bp1026b_II2523) were strikingly influenced by temperature and were dependent on a conserved GG(D/E)EF motif. The transposon insertion mutant exhibited enhanced biofilm formation at 37°C but impaired biofilm formation at 30°C. These studies illustrate the importance of studying behaviors regulated by cyclic di-GMP under varied environmental conditions in order to better understand cyclic di-GMP signaling in bacterial pathogens.IMPORTANCE This report evaluates predicted cyclic di-GMP binding and metabolic proteins from Burkholderia pseudomallei 1026b, a tier 1 select agent and the etiologic agent of melioidosis. Transposon insertion mutants with disruptions in each of the genes encoding these predicted proteins were characterized in order to identify key components of the B. pseudomallei cyclic di-GMP-signaling network. A predicted hydrolase and a phosphodiesterase that modulate swimming motility were identified, in addition to a diguanylate cyclase that modulates biofilm formation and motility in response to temperature. These studies warrant further evaluation of the contribution of cyclic di-GMP to melioidosis in the context of pathogen acquisition from environmental reservoirs and subsequent colonization, dissemination, and persistence within the host.}, } @article {pmid27956464, year = {2017}, author = {Reimche, JL and Kirse, DJ and Whigham, AS and Swords, WE}, title = {Resistance of non-typeable Haemophilus influenzae biofilms is independent of biofilm size.}, journal = {Pathogens and disease}, volume = {75}, number = {1}, pages = {}, pmid = {27956464}, issn = {2049-632X}, support = {R01 DC010051/DC/NIDCD NIH HHS/United States ; R01 DC012205/DC/NIDCD NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Haemophilus Infections/*microbiology ; Haemophilus influenzae/*drug effects/*physiology ; Humans ; Microbial Sensitivity Tests ; Otitis Media/drug therapy/microbiology ; }, abstract = {The inflammatory middle ear disease known as otitis media can become chronic or recurrent in some cases due to failure of the antibiotic treatment to clear the bacterial etiological agent. Biofilms are known culprits of antibiotic-resistant infections; however, the mechanisms of resistance for non-typeable Haemophilus influenzae biofilms have not been completely elucidated. In this study, we utilized in vitro static biofilm assays to characterize clinical strain biofilms and addressed the hypothesis that biofilms with greater biomass and/or thickness would be more resistant to antimicrobial-mediated eradication than thinner and/or lower biomass biofilms. Consistent with previous studies, antibiotic concentrations required to eliminate biofilm bacteria tended to be drastically higher than concentrations required to kill planktonic bacteria. The size characterizations of the biofilms formed by the clinical isolates were compared to their minimum biofilm eradication concentrations for four antibiotics. This revealed no correlation between biofilm thickness or biomass and the ability to resist eradication by antibiotics. Therefore, we concluded that biofilm size does not play a role in antibiotic resistance, suggesting that reduction of antibiotic penetration may not be a significant mechanism for antibiotic resistance for this bacterial opportunist.}, } @article {pmid27942649, year = {2017}, author = {Dranguet, P and Le Faucheur, S and Cosio, C and Slaveykova, VI}, title = {Influence of chemical speciation and biofilm composition on mercury accumulation by freshwater biofilms.}, journal = {Environmental science. Processes & impacts}, volume = {19}, number = {1}, pages = {38-49}, doi = {10.1039/c6em00493h}, pmid = {27942649}, issn = {2050-7895}, mesh = {*Biofilms ; Biological Availability ; Mercury/*analysis ; Rivers/chemistry/*microbiology ; Romania ; Water Pollutants, Chemical/*analysis ; Water Pollution, Chemical/*analysis ; }, abstract = {Mercury (Hg) is a pollutant of high concern for aquatic systems due to the biomagnification of its methylated form along the food chain. However, in contrast to other metals, gaining knowledge of its bioavailable forms for aquatic microorganisms remains challenging, making Hg risk assessment difficult. Ubiquitous and sessile freshwater biofilms are well known to accumulate and to transform Hg present in their ambient environment. The present study thus aims to evaluate whether non-extractable (proxy of intracellular) Hg accumulated by biofilms could be a good indicator of Hg bioavailability for microorganisms in freshwater. To that end, the link between Hg concentration and speciation, as well as biofilm composition (percentage of abiotic, biotic, chlorophyll and phycocyanin-fractions and abundance of dsrA, gcs, merA and hgcA bacterial genes) and biofilm Hg accumulation was examined. The studied biofilms were grown on artificial substrata in four reservoirs along the Olt River (Romania), which was contaminated by Hg coming from chlor-alkali plant effluents. The 0.45 μm-filterable Hg concentrations in ambient waters were measured and inorganic IHg speciation was modelled. Biofilms were analyzed for their non-extractable IHg and methylmercury (MeHg) contents as well as for their composition. The non-extractable IHg content was related, but not significantly, to the concentration of total IHg (r[2] = 0.88, p = 0.061) whereas a significant correlation was found with the predicted IHg concentration that is not bound to dissolved organic matter (r[2] = 0.95, p = 0.027), despite its extremely low concentrations (10[-25] M), showing a limitation of the thermodynamic Hg modelling to predict Hg bioavailability. The studied biofilms were different in biomass and composition and a principal component analysis showed that the non-extractable IHg content correlated with the abundance of the merA and hgcA genes, while MeHg accumulation was only linked with the abundance of the rRNA 16S gene. The present study suggests that non-extractable IHg concentrations in biofilms are a useful proxy of IHg bioavailable forms in waters whereas the hgcA and merA genes are good biomarkers of both biofilm IHg exposure and bioavailability.}, } @article {pmid27941713, year = {2016}, author = {Cai, S and Li, Y and Wang, K and Cen, Y and Lu, H and Dong, B and Chen, Y and Kong, J}, title = {Pathogenic Effects of Biofilm on Pseudomonas Aeruginosa Pulmonary Infection and Its Relationship to Cytokines.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {22}, number = {}, pages = {4869-4874}, pmid = {27941713}, issn = {1643-3750}, mesh = {Alginates/pharmacology ; Animals ; Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Bronchoalveolar Lavage Fluid/chemistry ; Cytokines/*metabolism ; Disease Models, Animal ; Freund's Adjuvant/pharmacology ; Glucuronic Acid/pharmacology ; Granulocyte Colony-Stimulating Factor/metabolism ; Hexuronic Acids/pharmacology ; Interleukin-17/metabolism ; Male ; Pneumonia/metabolism/*microbiology/therapy ; Pseudomonas Infections ; Pseudomonas aeruginosa/metabolism/pathogenicity/*physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {BACKGROUND An animal (Sprague-Dawley rat) model of Pseudomonas aeruginosa biofilm associated with chronic pulmonary infection in vivo was established and the effects of the biofilm on P. aeruginosa and its relationship to cytokines were investigated. MATERIAL AND METHODS Biofilm of P. aeruginosa in alginate beads and planktonic PA0725 were purified by anion-exchange chromatograph. Sprague-Dawley (SD) rats were immunized with the biofilm and then inhaled the same strain of P. aeruginosa. Anti-biofilm antibody titer was detected using the enzyme linked immunosorbent assay (ELISA) method. The cell count and differential count in the bronchoalveolar lavage fluid (BALF) were measured. The levels of cytokines (IL-17, IL-1β, MIP-2, and G-CSF) and tumor necrosis factor (TNF)-α in sera were also measured using an ELISA kit. RESULTS The sera anti-biofilm IgG antibody titer of immunized SD rats was increased significantly on the 5th and 8th days after inhalation. The IL-17 concentration was significantly higher on the 8th day after inhalation. The results indicated that when biofilm-pre-immunized rats were challenged with inhalation of PA0725 of P. aeruginosa, the biofilm acted as an antigen substance and mediated the antibody reaction of the antigen, which might cause serious airway inflammatory response and lung tissue injury. This effect may be related to IL-17. CONCLUSIONS P. aeruginosa biofilm protected the bacterium from antibiotics and might induce host immune damage in lung tissue and facilitate bacterium evading the host barrier.}, } @article {pmid27939826, year = {2017}, author = {Bao, P and Shen, Y and Lin, J and Haapasalo, M}, title = {In Vitro Efficacy of XP-endo Finisher with 2 Different Protocols on Biofilm Removal from Apical Root Canals.}, journal = {Journal of endodontics}, volume = {43}, number = {2}, pages = {321-325}, doi = {10.1016/j.joen.2016.09.021}, pmid = {27939826}, issn = {1878-3554}, mesh = {*Biofilms ; Humans ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Root Canal Irrigants/*therapeutic use ; Root Canal Preparation/*methods ; Tooth Apex ; Treatment Outcome ; }, abstract = {INTRODUCTION: The purpose of this study was to evaluate the effectiveness of the XP-endo Finisher (XPF; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) in biofilm removal in comparison with conventional needle irrigation (CNI) and passive ultrasonic irrigation (PUI) using an infected tooth model with an artificial apical groove.

METHODS: Fifty-four extracted human single-rooted premolars were selected. Each tooth was split longitudinally into 2 halves, with a groove made in the apical segment of the canal wall. After growing mixed bacteria biofilm for 4 weeks, the split halves were reassembled and instrumented using Vortex Blue files (Dentsply Tulsa Dental, Tulsa, OK) to size 40/.06. The instrumented teeth were randomly assigned to 6 groups (n = 8) according to the final irrigation protocol. Three different techniques (CNI, PUI, and XPF) were performed each with either continuous irrigation or 3-step irrigation. Scanning electron microscopic images were taken to evaluate the amount of residual biofilm inside and outside the groove.

RESULTS: Robust growth of biofilm was observed in each canal of the controls after 4 weeks. XPF showed the best biofilm removal efficacy inside and outside the groove followed by PUI and CNI (P < .05). The XPF 2 group using the 3-step protocol showed better antibiofilm efficiency than the XPF 1 group with continuous irrigation inside the groove (P < .05).

CONCLUSIONS: The XP-endo Finisher, as an irrigation agitation technique, may help to remove biofilm from hard-to-reach areas in the root canal system. The 3-step irrigation protocol was more effective than continuous irrigation when XPF was used.}, } @article {pmid27939148, year = {2016}, author = {Schönborn, S and Krömker, V}, title = {Detection of the biofilm component polysaccharide intercellular adhesin in Staphylococcus aureus infected cow udders.}, journal = {Veterinary microbiology}, volume = {196}, number = {}, pages = {126-128}, doi = {10.1016/j.vetmic.2016.10.023}, pmid = {27939148}, issn = {1873-2542}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Cattle ; Female ; Mammary Glands, Animal/microbiology ; Mastitis, Bovine/*microbiology ; Polysaccharides, Bacterial/genetics/*metabolism ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/drug effects/growth & development/*physiology ; beta-Glucans ; }, abstract = {Biofilms are communities of microorganisms embedded in a self-produced extracellular matrix made up of polymeric substances. They reduce the effects of antibiotics and allow the microorganisms to evade the innate immune system. This can lead to persistent or recurrent infections. In dairy cow herds, mastitis is a serious problem. The present study aimed to investigate the occurrence of biofilms in the udders of dairy cows infected with Staphylococcus (S.) aureus, because biofilms may affect the response to treatment of bovine mastitis. Immunofluorescence staining of polysaccharide intercellular adhesin (PIA), a component of S. aureus biofilms, was carried out based on swabs taken from different areas of S. aureus infected udders. We were able to demonstrate the presence of PIA in S. aureus infected bovine udders. However, the applied method is invasive and therefore only really suitable for scientific research and not for clinical diagnosis.}, } @article {pmid27938674, year = {2016}, author = {Boukahil, I and Czuprynski, CJ}, title = {Mannheimia haemolytica biofilm formation on bovine respiratory epithelial cells.}, journal = {Veterinary microbiology}, volume = {197}, number = {}, pages = {129-136}, pmid = {27938674}, issn = {1873-2542}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteriological Techniques/veterinary ; Biofilms/*growth & development ; *Cattle ; Drug Resistance, Bacterial ; Epithelial Cells/*microbiology ; Mannheimia haemolytica/drug effects/*physiology ; Respiratory Mucosa/*cytology ; }, abstract = {Mannheimia haemolytica is the most important bacterial agent associated with the bovine respiratory disease complex (BRDC), which causes worldwide economic losses to the cattle industry. M. haemolytica cells initially colonize the tonsillar crypts in the upper respiratory tract of cattle, from where they can subsequently descend into the lungs to cause disease. Many bacteria exist as biofilms inside their hosts. We hypothesize that M. haemolytica colonization of cattle during its commensal state may include biofilm formation. To begin to assess this possibility, we developed an in vitro system to study biofilm formation directly on bovine respiratory epithelial cells. Using fixed primary bovine bronchial epithelial cells, we observed M. haemolytica biofilm formation after a 48h incubation period at 37°C. Addition of mucin, the main component of mucus present in the upper respiratory tract, decreased M. haemolytica biofilm formation on bovine epithelial cells. We investigated the effects of prior viral infection of the epithelial cells on subsequent biofilm formation by M. haemolytica and found negligible effects. Utilization of this model system will provide new insights into the potential role of biofilm formation by M. haemolytica in the pathogenesis of BRDC.}, } @article {pmid27936266, year = {2016}, author = {Meleppat, RK and Shearwood, C and Keey, SL and Matham, MV}, title = {Quantitative optical coherence microscopy for the in situ investigation of the biofilm.}, journal = {Journal of biomedical optics}, volume = {21}, number = {12}, pages = {127002}, doi = {10.1117/1.JBO.21.12.127002}, pmid = {27936266}, issn = {1560-2281}, mesh = {*Biofilms ; Equipment Design ; Image Processing, Computer-Assisted/*methods ; Klebsiella pneumoniae ; Microscopy/*methods ; Tomography, Optical Coherence/*methods ; }, abstract = {This paper explores the potential of optical coherence microscopy (OCM) for the
METHODS: Clinical strains of Staphylococcus aureus, Pseudomonas aeruginosa, Bacteroides fragilis and Candida albicans isolated from peri-implantitis lesions were used. Biofilm was grown on sandblasted titanium discs and treated with erythritol/chlorhexidine. The antimicrobial activity was evaluated by determining the minimum inhibitory concentration and the minimum microbicidal concentration. The antibiofilm activity was assessed by semiquantitative spectrophotometric assay and by confocal laser scanning microscopy.

RESULTS: Erythritol/chlorhexidine displayed an inhibitory and a microbicidal activity against all the tested strains. The spectrophotometric analysis showed that the treatment was effective in both reducing the previously developed biofilm and decreasing biofilm formation on titanium surfaces. Confocal laser scanning microscopy analysis showed a significant reduction of the total biofilm volume, with an increase of the percentage of dead cells of all the microorganisms tested.

CONCLUSIONS: Erythritol/chlorhexidine displayed significant antimicrobial and antibiofilm activity against microorganisms isolated from peri-implantitis lesions. Due to its properties, it might represent a promising approach for the prevention and treatment of peri-implant diseases associated to microbial biofilm infections.}, } @article {pmid27932642, year = {2016}, author = {Duarte, VS and Dias, RS and Kropinski, AM and Vidigal, PM and Sousa, FO and Xavier, AS and Silva, CC and de Paula, SO}, title = {Complete Genome Sequence of vB_EcoM-UFV13, a New Bacteriophage Able To Disrupt Trueperella pyogenes Biofilm.}, journal = {Genome announcements}, volume = {4}, number = {6}, pages = {}, pmid = {27932642}, issn = {2169-8287}, abstract = {vB_EcoM-UFV13, a member of the T4virus genus, shows lytic activity against Escherichia coli and effectiveness in controlling the biofilm formed by Trueperella pyogenes, which qualifies it as a promising component of phage cocktails for mastitis and metritis control.}, } @article {pmid27930835, year = {2017}, author = {Ferrer, MD and Rodriguez, JC and Álvarez, L and Artacho, A and Royo, G and Mira, A}, title = {Effect of antibiotics on biofilm inhibition and induction measured by real-time cell analysis.}, journal = {Journal of applied microbiology}, volume = {122}, number = {3}, pages = {640-650}, doi = {10.1111/jam.13368}, pmid = {27930835}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Drug Resistance, Microbial/drug effects ; Humans ; Microbial Sensitivity Tests/methods ; Staphylococcus aureus/drug effects/isolation & purification/*physiology ; Staphylococcus epidermidis/drug effects/isolation & purification/*physiology ; }, abstract = {AIMS: The purpose of the current work was to study the pattern and dynamics of biofilm formation in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis in the presence of 10 antibiotics with different action mechanisms.

METHODS AND RESULTS: By using impedance measurements in microtitre plates with gold electrodes we have assessed the antibiotic effect on bacterial biofilm growth in real time. The impedance measurements appear to combine both cellular growth and matrix production, representing a measurement of total biofilm mass. Several clinical and reference strains were tested, showing different slopes and cell index values which correlated with their capacity to form biofilms as assessed by attachment to standard microtitre well plates and safranin staining. Biofilms were heavily reduced in biofilm mutants or by protease treatment in protein-based biofilm matrixes. Antibiotic resistance patterns of biofilms, which were very different to those obtained by traditional methods like epsilon-tests on solid media, revealed features that would pass unnoticed by end-point methods.

CONCLUSIONS: Once the biofilm is formed, antibiotic efficacy dramatically reduced and sub-inhibitory concentrations of some antibiotics, such as linezolid and clarithromycin, stimulated biofilm growth, stressing the importance of studying antibiotic resistance under biofilm growth conditions in real time.

Real-time biofilm analysis provides a promising tool to evaluate antibiotic therapy in clinical biofilm-mediated infections.}, } @article {pmid27929111, year = {2016}, author = {Martínez, E and Campos-Gómez, J}, title = {Oxylipins produced by Pseudomonas aeruginosa promote biofilm formation and virulence.}, journal = {Nature communications}, volume = {7}, number = {}, pages = {13823}, pmid = {27929111}, issn = {2041-1723}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; UL1 TR001417/TR/NCATS NIH HHS/United States ; }, mesh = {A549 Cells ; Animals ; Biofilms/*growth & development ; Drosophila ; Humans ; Lettuce ; Microbial Interactions ; *Oxylipins ; Pseudomonas aeruginosa/pathogenicity/*physiology ; Virulence ; }, abstract = {The oxygenation of unsaturated fatty acids by dioxygenases occurs in all kingdoms of life and produces physiologically important lipids called oxylipins. The biological roles of oxylipins have been extensively studied in animals, plants, algae and fungi, but remain largely unidentified in prokaryotes. The bacterium Pseudomonas aeruginosa displays a diol synthase activity that transforms several monounsaturated fatty acids into mono- and di-hydroxylated derivatives. Here we show that oxylipins derived from this activity inhibit flagellum-driven motility and upregulate type IV pilus-dependent twitching motility of P. aeruginosa. Consequently, these oxylipins promote bacterial organization in microcolonies, increasing the ability of P. aeruginosa to form biofilms in vitro and in vivo (in Drosophila flies). We also demonstrate that oxylipins produced by P. aeruginosa promote virulence in Drosophila flies and lettuce. Our study thus uncovers a role for prokaryotic oxylipins in the physiology and pathogenicity of bacteria.}, } @article {pmid27928939, year = {2017}, author = {Lal, S and Pearce, M and Achilles-Day, UE and Day, JG and Morton, LH and Crean, SJ and Singhrao, SK}, title = {Developing an ecologically relevant heterogeneous biofilm model for dental-unit waterlines.}, journal = {Biofouling}, volume = {33}, number = {1}, pages = {75-87}, doi = {10.1080/08927014.2016.1260710}, pmid = {27928939}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; Dental Equipment/*microbiology ; Disinfectants/pharmacology ; Equipment Contamination/*prevention & control ; Fungi/drug effects/isolation & purification ; Klebsiella/drug effects/isolation & purification ; Legionella pneumophila/drug effects/isolation & purification ; *Microbial Consortia ; *Models, Biological ; Pseudomonas/drug effects/isolation & purification ; Water Microbiology/*standards ; }, abstract = {This study monitored the biodiversity of microbes cultured from a heterogeneous biofilm which had formed on the lumen of a section of dental waterline tubing over a period of 910 days. By day 2 bacterial counts on the outlet-water showed that contamination of the system had occurred. After 14 days, a biofilm comparable to that of clinical waterlines, consisting of bacteria, fungi and amoebae had formed. This showed that the proprietary silver coating applied to the luminal surface of the commercial waterline tubing failed to prevent biofilm formation. Molecular barcoding of isolated culturable microorganisms showed some degree of the diversity of taxa in the biofilm, including the opportunistic pathogen Legionella pneumophila. Whilst the system used for isolation and identification of contaminating microorganisms may underestimate the diversity of organisms in the biofilm, their similarity to those found in the clinical environment makes this a promising test-bed for future biocide testing.}, } @article {pmid27927282, year = {2017}, author = {Arruda, CNF and Salles, MM and Badaró, MM and de Cássia Oliveira, V and Macedo, AP and Silva-Lovato, CH and de Freitas Oliveira Paranhos, H}, title = {Effect of sodium hypochlorite and Ricinus communis solutions on control of denture biofilm: A randomized crossover clinical trial.}, journal = {The Journal of prosthetic dentistry}, volume = {117}, number = {6}, pages = {729-734}, doi = {10.1016/j.prosdent.2016.08.035}, pmid = {27927282}, issn = {1097-6841}, mesh = {Aged ; Aged, 80 and over ; Biofilms/*drug effects ; Castor Oil/*therapeutic use ; Cross-Over Studies ; Denture Cleansers/*therapeutic use ; Dentures/microbiology ; Disinfectants/*therapeutic use ; Female ; Humans ; Male ; Middle Aged ; *Ricinus ; Sodium Hypochlorite/*therapeutic use ; Stomatitis, Denture/prevention & control ; Treatment Outcome ; }, abstract = {STATEMENT OF PROBLEM: The prevalence of complete edentulism remains high in the elderly, and previous data have shown that poor denture hygiene is common among patients with edentulism.

PURPOSE: The purpose of this randomized crossover trial was to evaluate the efficacy of denture cleansers in terms of biofilm removal, antimicrobial action, and the remission of denture stomatitis.

MATERIAL AND METHODS: Fifty denture wearers with denture stomatitis were instructed to brush their dentures (brush and soap) and to soak them (20 minutes/14 days) in 4 solutions, as follows: C (control), 0.85% saline; SH1, 0.1% sodium hypochlorite; SH2, 0.2% sodium hypochlorite; and RC, 8% Ricinus communis. The biofilm in the intaglio surface of maxillary dentures was stained, photographed, and quantified by software (Image Tool). It was then collected (brushed with saline solution), and the obtained suspension was diluted (10[0] to 10[-3]) and seeded (50 μL) in CHROMagar for Candida spp. After incubation, colony-forming units per milliliter values were calculated. Denture stomatitis remission was classified according to the Newton classification. Data were analyzed by Friedman (α=.05) and Wilcoxon tests and corrected by the Bonferroni test (α=.005).

RESULTS: SH1 (mean rank [MR]=1.98) and SH2 (MR=1.64) showed lower biofilm coverage than C (MR=3.73) that was similar to RC (MR=2.92). SH1 (MR=2.43) and SH2 (MR=2.10) showed antimicrobial action for Candida spp, and RC (MR=3.36) showed similar results to C (MR=3.51) and baseline (MR=3.50). Clinical signs of denture stomatitis were reduced by SH1 (MR=2.44), while SH2 (MR=2.56) and RC (MR=2.74) showed intermediate results.

CONCLUSIONS: The two sodium hypochlorite solutions were the most effective means of biofilm control. All tested solutions were effective in reducing the signs of denture stomatitis.}, } @article {pmid27925711, year = {2016}, author = {Szczotko, M and Stankiewicz, A and Jamsheer-Bratkowska, M}, title = {Evaluation of susceptibility of polymer and rubber materials intended into contact with drinking water on biofilm formation.}, journal = {Roczniki Panstwowego Zakladu Higieny}, volume = {67}, number = {4}, pages = {409-417}, pmid = {27925711}, issn = {0035-7715}, mesh = {Biofilms/*growth & development ; Drinking Water/*analysis/*microbiology ; Environmental Exposure ; Environmental Monitoring ; Humans ; *Materials Testing ; Poland ; Polymers/*analysis ; Rubber/*analysis ; *Sanitary Engineering ; Water Microbiology ; }, abstract = {BACKGROUND: Plumbing materials in water distribution networks and indoor installations are constantly evolving. The application of new, more economical solutions with plastic materials eliminates the corrosion problems, however, do not fully protect the consumer against secondary microbial contamination of water intended for human consumption caused by the presence of a biofilm on the inner surface of materials applied. National Institute of Public Health - National Institute of Hygiene conducts research aimed at a comprehensive assessment of this type of materials, resulting their further marketing authorization in Poland.

OBJECTIVES: Evaluation and comparison of polymer and rubber materials intended to contact with water for the susceptibility to biofilm formation.

MATERIALS AND METHODS: Plastic materials (polyethylene, polypropylene, polyvinyl chloride) and rubber compounds (EPDM, NBR), from different manufacturers were evaluated. The study was carried out on 37 samples, which were divided into groups according to the material of which they were made. The testing was conducted according to the method based on conditions of dynamic flow of tap water. The level of bioluminescence in swabs taken from the surface of the tested materials was investigated with a luminometer.

RESULTS: Evaluation of plastic materials does not show major objections in terms of hygienic assessment. All materials met the evaluation criteria established for methodology used. In case of rubber compounds, a substantial part clearly exceeded the limit values, which resulted in their negative assessment and elimination of these materials from domestic market.

CONCLUSIONS: High susceptibility to the formation of biofilm in the group of products made of rubber compounds has been demonstrated. Examined plastic materials, except for several cases, do not revealed susceptibility to biofilm formation, but application of plastics for distribution of water intended for human consumption does not fully protect water from secondary, microbiological contamination. Complete verification of plumbing materials including biofilm formation test before their introduction into the domestic market should be continued.}, } @article {pmid27925693, year = {2017}, author = {Abouelhassan, Y and Basak, A and Yousaf, H and Huigens, RW}, title = {Identification of N-Arylated NH125 Analogues as Rapid Eradicating Agents against MRSA Persister Cells and Potent Biofilm Killers of Gram-Positive Pathogens.}, journal = {Chembiochem : a European journal of chemical biology}, volume = {18}, number = {4}, pages = {352-357}, doi = {10.1002/cbic.201600622}, pmid = {27925693}, issn = {1439-7633}, mesh = {Acetamides/chemistry ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Erythrocytes/drug effects ; Gram-Positive Bacteria/*drug effects ; Humans ; Imidazoles/*chemistry/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Pyridines/chemistry ; }, abstract = {Bacterial biofilms housing dormant persister cells are innately tolerant to antibiotics and disinfectants, yet several membrane-active agents are known to eradicate tolerant bacterial cells. NH125, a membrane-active persister killer and starting point for development, led to the identification of two N-arylated analogues (1 and 2) that displayed improved biofilm eradication potencies compared to the parent compound and rapid persister-cell-killing activities in stationary cultures of methicillin-resistant Staphylococcus aureus (MRSA). We found 1 and 2 to be superior to other membrane-active agents in biofilm eradication assays, with 1 demonstrating minimum biofilm eradication concentrations (MBEC) of 23.5, 11.7, and 2.35 μm against MRSA, methicillin-resistant Staphylococcus epidermidis (MRSE), and vancomycin-resistant Enterococcus faecium (VRE) biofilms, respectively. We tested our panel of membrane-active agents against MRSA stationary cultures and found 1 to rapidly eradicate MRSA stationary cells by 4 log units (99.99 %) in 30 min. The potent biofilm eradication and rapid persister-cell-killing activities exhibited by N-arylated NH125 analogues could have significant impact in addressing biofilm-associated problems.}, } @article {pmid27925498, year = {2017}, author = {Zhang, S and Song, HL and Yang, XL and Long, XZ and Liu, X and Chen, TQ}, title = {Behavior of tetracycline and sulfamethoxazole and their corresponding resistance genes in three-dimensional biofilm-electrode reactors with low current.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {52}, number = {4}, pages = {333-340}, doi = {10.1080/10934529.2016.1258870}, pmid = {27925498}, issn = {1532-4117}, mesh = {Anti-Bacterial Agents/analysis/*chemistry ; Bacteria/*genetics ; Biofilms/*drug effects ; China ; Drug Resistance, Microbial/genetics ; Environmental Restoration and Remediation/instrumentation/methods ; Sulfamethoxazole/analysis/*chemistry ; Tetracycline/analysis/*chemistry ; Wastewater/*microbiology ; Water Pollutants, Chemical/analysis/chemistry ; }, abstract = {Antibiotics and antibiotic resistance genes (ARGs) have become major health concerns. In this study, three-dimensional biofilm-electrode reactors (3D-BERs) under low current were designed to assess their performance in removing tetracycline (TC) and sulfamethoxazole (SMX) from synthetic wastewater. In addition, the fates of the corresponding ARGs in microbial communities were investigated. The mass removal ratios of TC and SMX by the 3D-BERs were 82.6-97.3% and 72.2-93.2%, respectively. There were obvious increases in the relative abundances of all target genes after ∼2 months. The tet and sul genes were significantly upregulated by high concentrations of antibiotics in the cathode layer, and higher ARG levels were evident in the cathodes than in the anodes. High-throughput sequencing identified Methylotenera, Candidatus Accumulibacter, Limnohabitans, Dechloromonas, Crenothrix, and Caldilinea as the dominant genera in the samples at the end of the experiment, after ∼8 months, and these bacteria potentially exhibited antibiotic resistance. The relative abundances and compositions of the dominant microbial populations changed throughout the course of antibiotic removal in the 3D-BERs.}, } @article {pmid27923605, year = {2017}, author = {Wunnoo, S and Saising, J and Voravuthikunchai, SP}, title = {Rhodomyrtone inhibits lipase production, biofilm formation, and disorganizes established biofilm in Propionibacterium acnes.}, journal = {Anaerobe}, volume = {43}, number = {}, pages = {61-68}, doi = {10.1016/j.anaerobe.2016.12.002}, pmid = {27923605}, issn = {1095-8274}, mesh = {Acne Vulgaris/*microbiology ; Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Humans ; Lipase/drug effects/metabolism ; Microbial Sensitivity Tests ; Myrtaceae/*chemistry ; Peptide Hydrolases/drug effects/metabolism ; Plant Extracts/chemistry/*pharmacology ; Plant Leaves/chemistry ; Propionibacterium acnes/*drug effects/enzymology/growth & development ; Xanthones/chemistry/*pharmacology ; }, abstract = {Virulence enzymes and biofilm a play crucial role in the pathogenesis of Propionibacterium acnes, a major causative agent of acne vulgaris. In the present study, the effects of rhodomyrtone, a pure compound identified from Rhodomyrtus tomentosa (Aiton) Hassk. leaves extract against enzyme production and biofilm formation production by 5 clinical isolates and a reference strain were evaluated. The degree of hydrolysis by both lipase and protease enzymes significantly decreased upon treatment with the compound at 0.125-0.25 μg/mL (p < 0.05). Lipolytic zones significantly reduced in all isolates while decrease in proteolytic activities was found only in 50% of the isolates. Rhodomyrtone at 1/16MIC and 1/8MIC caused significant reduction in biofilm formation of the clinical isolates (p < 0.05). Percentage viability of P. acnes within mature biofilm upon treated with the compound at 4MIC and 8MIC ranged between 40% and 85%. Pronounced properties of rhodomyrtone suggest a path towards developing a novel anti-acne agent.}, } @article {pmid27923523, year = {2017}, author = {Malinowski, AM and McClarty, BM and Robinson, C and Spear, W and Sanchez, M and Sparkes, TC and Brooke, JS}, title = {Polysorbate 80 and polymyxin B inhibit Stenotrophomonas maltophilia biofilm.}, journal = {Diagnostic microbiology and infectious disease}, volume = {87}, number = {2}, pages = {154-156}, doi = {10.1016/j.diagmicrobio.2016.11.008}, pmid = {27923523}, issn = {1879-0070}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Drug Interactions ; Humans ; Microbial Sensitivity Tests ; Polymyxin B/*pharmacology ; Polysorbates/*pharmacology ; Stenotrophomonas maltophilia/*drug effects/*physiology ; Surface-Active Agents/*pharmacology ; }, abstract = {Stenotrophomonas maltophilia is an opportunistic multiple-drug-resistant human pathogen that forms biofilms on implanted medical devices. We examined the potential inhibitory activity of polysorbate 80 and polymyxin B against S. maltophilia. A combination of subMIC polymyxin B and polysorbate 80 was the most effective inhibitor of growth and biofilm formation.}, } @article {pmid27922663, year = {2017}, author = {Ou, M and Ling, J}, title = {Norspermidine changes the basic structure of S. mutans biofilm.}, journal = {Molecular medicine reports}, volume = {15}, number = {1}, pages = {210-220}, pmid = {27922663}, issn = {1791-3004}, mesh = {Biofilms/*growth & development ; Dental Plaque/*microbiology ; Gene Expression Regulation, Bacterial ; Humans ; Polysaccharides, Bacterial/metabolism/*ultrastructure ; Quorum Sensing ; Spermidine/*analogs & derivatives/metabolism ; Streptococcus mutans/genetics/growth & development/*physiology ; }, abstract = {The factors regulating the assembly of the three-dimensional structure of Streptococcus mutans biofilms remain obscure. Polyamines are essential in biofilm formation of certain bacteria. Norspermidine, an unusual polyamine, has been a controversial polyamine that can lead to biofilm disassembly. However, the role of norspermidine in S. mutans biofilms remains unknown. Therefore, the present study investigated the impact of norspermidine on S. mutans biofilms. The different architectures of the biofilms in norspermidine and control groups indicated that the basic units, bacteria‑exopolysaccharide units (BEUs), represent the exopolysaccharide (EPS) and bacterial assembly pattern in S. mutans biofilms. In addition, norspermidine inhibited S. mutans biofilm formation and changed the basic composition of the biofilm, which led to an unusual EPS architecture. Therefore, 5 mM norspermidine inhibited biofilm formation both by decreasing the rate of cell viability and changing the biofilm structure. Gene‑expression microarray analysis indicated that the formation of an irregular architecture in the norspermidine group was potentially attributable to the downregulation of elements of the quorum‑sensing system (by 2.7‑15‑fold). The present study suggested that the BEUs are a basic structure of S. mutans biofilm and its assembly is regulated majorly by the quorum‑sensing system. Norspermidine can lead to structure change in BEUs by influencing S. mutans quorum-sensing system.}, } @article {pmid27921012, year = {2016}, author = {Arenas, J and Paganelli, FL and Rodríguez-Castaño, P and Cano-Crespo, S and van der Ende, A and van Putten, JP and Tommassen, J}, title = {Expression of the Gene for Autotransporter AutB of Neisseria meningitidis Affects Biofilm Formation and Epithelial Transmigration.}, journal = {Frontiers in cellular and infection microbiology}, volume = {6}, number = {}, pages = {162}, pmid = {27921012}, issn = {2235-2988}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Cell Line ; Epithelial Cells/*microbiology ; Gene Expression Regulation, Bacterial ; Humans ; Membrane Proteins/*metabolism ; Neisseria meningitidis/genetics/*physiology ; Type V Secretion Systems/*metabolism ; }, abstract = {Neisseria meningitidis is a Gram-negative bacterium that resides as a commensal in the upper respiratory tract of humans, but occasionally, it invades the host and causes sepsis and/or meningitis. The bacterium can produce eight autotransporters, seven of which have been studied to some detail. The remaining one, AutB, has not been characterized yet. Here, we show that the autB gene is broadly distributed among pathogenic Neisseria spp. The gene is intact in most meningococcal strains. However, its expression is prone to phase variation due to slipped-strand mispairing at AAGC repeats located within the DNA encoding the signal sequence and is switched off in the vast majority of these strains. Moreover, various genetic disruptions prevent autB expression in most of the strains in which the gene is in phase indicating a strong selection against AutB synthesis. We observed that autB is expressed in two of the strains examined and that AutB is secreted and exposed at the cell surface. Functionality assays revealed that AutB synthesis promotes biofilm formation and delays the passage of epithelial cell layers in vitro. We hypothesize that this autotransporter is produced during the colonization process only in specific niches to facilitate microcolony formation, but its synthesis is switched off probably to evade the immune system and facilitate human tissue invasion.}, } @article {pmid27920774, year = {2016}, author = {Nielsen, CK and Kjems, J and Mygind, T and Snabe, T and Meyer, RL}, title = {Effects of Tween 80 on Growth and Biofilm Formation in Laboratory Media.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1878}, pmid = {27920774}, issn = {1664-302X}, abstract = {Tween 80 is a widely used non-ionic emulsifier that is added to cosmetics, pharmaceuticals, and foods. Because of its widespread use we need to understand how it affects bacteria on our skin, in our gut, and in food products. The aim of this study is to investigate how Tween 80 affects the growth and antimicrobial susceptibility of Staphylococcus aureus, Listeria monocytogenes, and Pseudomonas fluorescens, which are common causes of spoilage and foodborne illnesses. Addition of 0.1% Tween 80 to laboratory growth media increased the growth rate of planktonic S. aureus batch cultures, and it also increased the total biomass when S. aureus was grown as biofilms. In contrast, Tween 80 had no effect on batch cultures of L. monocytogenes, it slowed the growth rate of P. fluorescens, and it led to formation of less biofilm by both L. monocytogenes and P. fluorescens. Furthermore, Tween 80 lowered the antibacterial efficacy of two hydrophobic antimicrobials: rifampicin and the essential oil isoeugenol. Our findings underline the importance of documenting indirect effects of emulsifiers when studying the efficacy of hydrophobic antimicrobials that are dispersed in solution by emulsification, or when antimicrobials are applied in food matrixes that include emulsifiers. Furthermore, the species-specific effects on microbial growth suggests that Tween 80 in cosmetics and food products could affect the composition of skin and gut microbiota, and the effect of emulsifiers on the human microbiome should therefore be explored to uncover potential health effects.}, } @article {pmid27920773, year = {2016}, author = {Vegge, CS and Jansen van Rensburg, MJ and Rasmussen, JJ and Maiden, MC and Johnsen, LG and Danielsen, M and MacIntyre, S and Ingmer, H and Kelly, DJ}, title = {Glucose Metabolism via the Entner-Doudoroff Pathway in Campylobacter: A Rare Trait that Enhances Survival and Promotes Biofilm Formation in Some Isolates.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1877}, pmid = {27920773}, issn = {1664-302X}, support = {/WT_/Wellcome Trust/United Kingdom ; }, abstract = {Isolates of the zoonotic pathogen Campylobacter are generally considered to be unable to metabolize glucose due to lack of key glycolytic enzymes. However, the Entner-Doudoroff (ED) pathway has been identified in Campylobacter jejuni subsp. doylei and a few C. coli isolates. A systematic search for ED pathway genes in a wide range of Campylobacter isolates and in the C. jejuni/coli PubMLST database revealed that 1.7% of >6,000 genomes encoded a complete ED pathway, including both C. jejuni and C. coli from diverse clinical, environmental and animal sources. In rich media, glucose significantly enhanced stationary phase survival of a set of ED-positive C. coli isolates. Unexpectedly, glucose massively promoted floating biofilm formation in some of these ED-positive isolates. Metabolic profiling by gas chromatography-mass spectrometry revealed distinct responses to glucose in a low biofilm strain (CV1257) compared to a high biofilm strain (B13117), consistent with preferential diversion of hexose-6-phosphate to polysaccharide in B13117. We conclude that while the ED pathway is rare amongst Campylobacter isolates causing human disease (the majority of which would be of agricultural origin), some glucose-utilizing isolates exhibit specific fitness advantages, including stationary-phase survival and biofilm production, highlighting key physiological benefits of this pathway in addition to energy conservation.}, } @article {pmid27917856, year = {2016}, author = {Al-Shabib, NA and Husain, FM and Ahmed, F and Khan, RA and Ahmad, I and Alsharaeh, E and Khan, MS and Hussain, A and Rehman, MT and Yusuf, M and Hassan, I and Khan, JM and Ashraf, GM and Alsalme, A and Al-Ajmi, MF and Tarasov, VV and Aliev, G}, title = {Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36761}, pmid = {27917856}, issn = {2045-2322}, mesh = {Biofilms/drug effects ; Chromobacterium/drug effects/metabolism/physiology ; Food Packaging ; Food Preservatives/chemistry/metabolism/pharmacology ; Microscopy, Electron, Transmission ; Nanostructures/*chemistry/ultrastructure ; Nigella sativa/*metabolism ; Prospective Studies ; Pseudomonas aeruginosa/drug effects/metabolism/physiology ; Quorum Sensing/drug effects ; Seeds/*metabolism ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction ; Zinc Oxide/chemistry/*metabolism/pharmacology ; }, abstract = {Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative.}, } @article {pmid27916605, year = {2017}, author = {Zmantar, T and Ben Slama, R and Fdhila, K and Kouidhi, B and Bakhrouf, A and Chaieb, K}, title = {Modulation of drug resistance and biofilm formation of Staphylococcus aureus isolated from the oral cavity of Tunisian children.}, journal = {The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases}, volume = {21}, number = {1}, pages = {27-34}, pmid = {27916605}, issn = {1678-4391}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/pharmacology ; Benzalkonium Compounds/pharmacology ; Biofilms/drug effects/*growth & development ; Child ; Chlorhexidine/pharmacology ; Drug Resistance, Bacterial/*drug effects ; Humans ; Lactobacillus plantarum/chemistry ; Microbial Sensitivity Tests ; Microscopy, Atomic Force/methods ; Mouth/*microbiology ; Polymerase Chain Reaction ; Reference Values ; Reproducibility of Results ; Staphylococcus aureus/*drug effects/isolation & purification ; Statistics, Nonparametric ; Tetracycline/pharmacology ; }, abstract = {OBJECTIVES: This study aims to investigate the antimicrobial and the anti-biofilm activities of Lactobacillus plantarum extract (LPE) against a panel of oral Staphylococcus aureus (n=9) and S. aureus ATCC 25923. The in vitro ability of LPE to modulate bacterial resistance to tetracycline, benzalchonium chloride, and chlorhexidine were tested also.

METHODS: The minimum inhibitory concentrations (MICs) and the minimal bactericidal concentrations of Lactobacillus plantarum extract, tetracycline, benzalchonium chloride and clohrhexidine were determined in absence and in presence of a sub-MIC doses of LPE (1/2 MIC). In addition, the LPE potential to inhibit biofilm formation was assessed by microtiter plate and atomic force microscopy assays. Statistical analysis was performed on SPSS v. 17.0 software using Friedman test and Wilcoxon signed ranks test. These tests were used to assess inter-group difference (p<0.05).

RESULTS: Our results revealed that LPE exhibited a significant antimicrobial and anti-biofilm activities against the tested strains. A synergistic effect of LPEs and drug susceptibility was observed with a 2-8-fold reduction.

CONCLUSION: LPE may be considered to have resistance-modifying activity. A more detailed investigation is necessary to determine the active compound responsible for therapeutic and disinfectant modulation.}, } @article {pmid27915337, year = {2016}, author = {Gao, M and Wang, H and Zhu, L}, title = {Quercetin Assists Fluconazole to Inhibit Biofilm Formations of Fluconazole-Resistant Candida Albicans in In Vitro and In Vivo Antifungal Managements of Vulvovaginal Candidiasis.}, journal = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology}, volume = {40}, number = {3-4}, pages = {727-742}, doi = {10.1159/000453134}, pmid = {27915337}, issn = {1421-9778}, mesh = {Animals ; Antifungal Agents/pharmacology/*therapeutic use ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/growth & development/isolation & purification/*physiology ; Candidiasis, Vulvovaginal/*drug therapy/microbiology ; Cell Membrane/drug effects/metabolism ; Disease Models, Animal ; Drug Resistance, Fungal/*drug effects ; Drug Synergism ; Female ; Flocculation ; Fluconazole/pharmacology/*therapeutic use ; Gene Expression Regulation, Fungal/drug effects ; Hydrophobic and Hydrophilic Interactions ; Hyphae/drug effects ; Mice ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Plankton/drug effects ; Quercetin/pharmacology/*therapeutic use ; RNA, Messenger/genetics/metabolism ; }, abstract = {BACKGROUND: Vulvovaginal candidiasis (VVC) is a common gynecological disease. Candida albicans is believed to be mainly implicated in VVC occurrence, the biofilm of which is one of the virulence factors responsible for resistance to traditional antifungal agents especially to fluconazole (FCZ). Quercetin (QCT) is a dietary flavonoid and has been demonstrated to be antifungal against C. albicans biofilm.

METHODS: 17 C. albicans isolates including 15 clinical ones isolated from VVC patients were employed to investigate the effects of QCT and/or FCZ on the inhibition of C. albicans biofilm.

RESULTS: We observed that 64 µg/mL QCT and/or 128 µg/mL FCZ could (i) be synergistic against 10 FCZ-resistant planktonic and 17 biofilm cells of C. albicans, (ii) inhibit fungal adherence, cell surface hydrophobicity (CSH), flocculation, yeast-to-hypha transition, metabolism, thickness and dispersion of biofilms; (iii) down-regulate the expressions of ALS1, ALS3, HWP1, SUN41, UME6 and ECE1 and up-regulate the expressions of PDE2, NRG1 and HSP90, and we also found that (iv) the fungal burden was reduced in vaginal mucosa and the symptoms were alleviated in a murine VVC model after the treatments of 5 mg/kg QCT and/or 20 mg/kg FCZ.

CONCLUSION: Together with these results, it could be demonstrated that QCT could be a favorable antifungal agent and a promising synergist with FCZ in the clinical management of VVC caused by C. albicans biofilm.}, } @article {pmid27915018, year = {2017}, author = {Mishra, B and Lushnikova, T and Golla, RM and Wang, X and Wang, G}, title = {Design and surface immobilization of short anti-biofilm peptides.}, journal = {Acta biomaterialia}, volume = {49}, number = {}, pages = {316-328}, pmid = {27915018}, issn = {1878-7568}, support = {R01 AI105147/AI/NIAID NIH HHS/United States ; R03 AI128230/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Anti-Infective Agents/pharmacology ; Antifungal Agents/pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Biophysical Phenomena ; Cell Death/drug effects ; Fungi/drug effects ; HEK293 Cells ; HeLa Cells ; Humans ; Hydrogen-Ion Concentration ; Immobilized Proteins/*pharmacology ; Kinetics ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Peptides/chemistry/*pharmacology ; Photoelectron Spectroscopy ; Polyethylene Terephthalates/chemistry ; Protein Stability/drug effects ; Salts/pharmacology ; Serum/metabolism ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; }, abstract = {UNLABELLED: Short antimicrobial peptides are essential to keep us healthy and their lasting potency can inspire the design of new types of antibiotics. This study reports the design of a family of eight-residue tryptophan-rich peptides (TetraF2W) obtained by converting the four phenylalanines in temporin-SHf to tryptophans. The temporin-SHf template was identified from the antimicrobial peptide database (http://aps.unmc.edu/AP). Remarkably, the double arginine variant (TetraF2W-RR) was more effective in killing methicillin-resistant Staphylococcus aureus (MRSA) USA300, but less cytotoxic to human skin HaCat and kidney HEK293 cells, than the lysine-containing dibasic combinations (KR, RK and KK). Killing kinetics and fluorescence spectroscopy suggest membrane targeting of TetraF2W-RR, making it more difficult for bacteria to develop resistance. Because established biofilms on medical devices are difficult to remove, we chose to covalently immobilize TetraF2W-RR onto the polyethylene terephthalate (PET) surface to prevent biofilm formation. The successful surface coating of the peptide is supported by FT-IR and XPS spectroscopies, chemical quantification, and antibacterial assays. This peptide-coated surface indeed prevented S. aureus biofilm formation with no cytotoxicity to human cells. In conclusion, TetraF2W-RR is a short Trp-rich peptide with demonstrated antimicrobial and anti-biofilm potency against MRSA in both the free and immobilized forms. Because these short peptides can be synthesized cost effectively, they may be developed into new antimicrobial agents or used as surface coating compounds.

STATEMENT OF SIGNIFICANCE: It is stunning that the total deaths due to methicillin-resistant Staphylococcus aureus (MRSA) infection are comparable to AIDS/HIV-1, making it urgent to explore new possibilities. This study deals with this problem by two strategies. First, we have designed a family of novel antimicrobial peptides with merely eight amino acids, making it cost effective for chemical synthesis. These peptides are potent against MRSA USA300. Our study uncovers that the high potency of the tryptophan-rich short peptide is coupled with arginines, whereas these Trp- and Arg-rich peptides are less toxic to select human cells than the lysine-containing analogs. Such a combination generates a more selective peptide. As a second strategy, we also demonstrate successful covalent immobilization of this short peptide to the polyethylene terephthalate (PET) surface by first using a chitosan linker, which is easy to obtain. Because biofilms on medical devices are difficult to remove by traditional antibiotics, we also show that the peptide coated surface can prevent biofilm formation. Although rarely demonstrated, we provide evidence that both the free and immobilized peptides target bacterial membranes, rendering it difficult for bacteria to develop resistance. Collectively, the significance of our study is the design of novel antimicrobial peptides provides a useful template for developing novel antimicrobials against MRSA. In addition, orientation-specific immobilization of the same short peptide can prevent biofilm formation on the PET surface, which is widely used in making prosthetic heart valves cuffs and other bio devices.}, } @article {pmid27914087, year = {2017}, author = {Chao, Y and Bergenfelz, C and Håkansson, AP}, title = {In Vitro and In Vivo Biofilm Formation by Pathogenic Streptococci.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1535}, number = {}, pages = {285-299}, doi = {10.1007/978-1-4939-6673-8_19}, pmid = {27914087}, issn = {1940-6029}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Biomass ; Cell Line ; Drug Resistance, Bacterial ; Humans ; Mice ; Microbial Sensitivity Tests ; Nasopharynx/microbiology ; Polymerase Chain Reaction ; RNA, Bacterial ; Respiratory Mucosa/microbiology ; Streptococcal Infections/*microbiology ; Streptococcus/drug effects/*physiology/ultrastructure ; Streptococcus pneumoniae/physiology/ultrastructure ; }, abstract = {This manuscript presents novel approaches to grow and evaluate Streptococcal biofilm formation using the human respiratory pathogen Streptococcus pneumoniae (the pneumococcus) as the main model organism on biological surfaces in vitro and in vivo. Most biofilm models are based on growth on abiotic surfaces, which is relevant for many pathogens whose growth on surfaces or medical devices is a major cause of disease transmission and infections, especially in hospital environments. However, most infections with commensal organisms require biofilm formation on biological surfaces in the host at the site of colonization or infection. In vitro model systems incorporating biological components from the host and taking into account the host environment of the infectious site are not well described.In a series of publications, we have shown that S. pneumoniae form complex biofilms in the nasopharynx of mice and have devised methodology to evaluate the biofilm structure and function in this environment. We have also been able to recapitulate this biofilm phenotype in vitro by incorporating crucial factors associated with the host environment. Although the protocols presented in this manuscript are focused on S. pneumoniae, the same methodology can and has been used for other Streptococcal species that form biofilms on mucosal surfaces.}, } @article {pmid27914001, year = {2017}, author = {Algburi, A and Zehm, S and Netrebov, V and Bren, AB and Chistyakov, V and Chikindas, ML}, title = {Subtilosin Prevents Biofilm Formation by Inhibiting Bacterial Quorum Sensing.}, journal = {Probiotics and antimicrobial proteins}, volume = {9}, number = {1}, pages = {81-90}, pmid = {27914001}, issn = {1867-1314}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacillus subtilis/chemistry ; Bacteriocins/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/*drug effects/physiology ; Gram-Positive Bacteria/*drug effects/physiology ; Peptides, Cyclic/isolation & purification/*pharmacology ; Quorum Sensing/*drug effects ; }, abstract = {Subtilosin, the cyclic lantibiotic protein produced by Bacillus subtilis KATMIRA1933, targets the surface receptor and electrostatically binds to the bacterial cell membrane. In this study, subtilosin was purified using ammonium sulfate ((NH4)2SO4) precipitation and purified via column chromatography. Subtilosin's antibacterial minimum and sub-minimum inhibitory concentrations (MIC and sub-MIC) and anti-biofilm activity (biofilm prevention) were established. Subtilosin was evaluated as a quorum sensing (QS) inhibitor in Gram-positive bacteria using Fe(III) reduction assay. In Gram-negative bacteria, subtilosin was evaluated as a QS inhibitor utilizing Chromobacterium voilaceum as a microbial reporter. The results showed that Gardnerella vaginalis was more sensitive to subtilosin with MIC of 6.25 μg/mL when compared to Listeria monocytogenes (125 μg/mL). The lowest concentration of subtilosin, at which more than 90% of G. vaginalis biofilm was inhibited without effecting the growth of planktonic cells, was 0.78 μg/mL. About 80% of L. monocytogenes and more than 60% of Escherichia coli biofilm was inhibited when 15.1 μg/mL of subtilosin was applied. Subtilosin with 7.8-125 μg/mL showed a significant reduction in violacein production without any inhibitory effect on the growth of C. violaceum. Subtilosin at 3 and 4 μg/mL reduced the level of Autoinducer-2 (AI-2) production in G. vaginalis. However, subtilosin did not influence AI-2 production by L. monocytogenes at sub-MICs of 0.95-15.1 μg/mL. To our knowledge, this is the first report exploring the relationship between biofilm prevention and quorum sensing inhibition in G. vaginalis using subtilosin as a quorum sensing inhibitor.}, } @article {pmid27913890, year = {2017}, author = {Yang, GF and Feng, LJ and Guo, CR and Xia, T and Xu, XY and Zhu, L}, title = {Performance improvement of raw water pretreatment process with pre-inoculation biofilm: feasibility and limiting factors.}, journal = {Biodegradation}, volume = {28}, number = {1}, pages = {111-123}, doi = {10.1007/s10532-016-9781-6}, pmid = {27913890}, issn = {1572-9729}, mesh = {Biodegradation, Environmental ; *Biofilms/growth & development ; *Bioreactors ; Feasibility Studies ; Risk Assessment ; Rivers/chemistry ; Water Pollutants, Chemical/*isolation & purification ; Water Purification/*methods ; }, abstract = {The initial formation of biofilm and the removal performance of pollutants in biological pretreatment process for polluted raw water were limited due to the oligotrophic niche in raw water. In this study, the feasibility of using pre-inoculation biofilm formed under nutrients enhanced condition for polluted raw water treatment was analyzed in nine batch reactors. Results showed that the pollutants removal performance of biofilm was improved under nutrients enhanced conditions. Ammonia oxidation rate (AOR) was exponentially increased with the increasing in NH4[+]-N levels, and organic matter removal rate (ORR) was positively related to the initial total organic carbon (TOC) concentration. The biofilm formation and microbial diversity were further improved via adding more substrates, seeding river sediment and feeding effluent from a mature biofilm reactor. However, the biofilm formed under higher substrate conditions had higher half-saturation constant values (K S) to both NH4[+]-N and TOC, which decreased AOR and ORR values when it was used to treat polluted raw water. The reduction percentage of AOR and ORR showed logarithmic growth modes with the increase in K S values. Fortunately, improvement of nutrients flux via accelerating influent replacement could enhance the start-up performance effectively and decrease the operation risk introduced by the changes in substrate affinity.}, } @article {pmid27913076, year = {2017}, author = {Marques, VF and Motta, CC and Soares, BD and Melo, DA and Coelho, SM and Coelho, ID and Barbosa, HS and Souza, MM}, title = {Biofilm production and beta-lactamic resistance in Brazilian Staphylococcus aureus isolates from bovine mastitis.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {48}, number = {1}, pages = {118-124}, pmid = {27913076}, issn = {1678-4405}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; *Biofilms ; Cattle ; Female ; Genetic Association Studies ; Mastitis, Bovine/*microbiology ; Microbial Sensitivity Tests ; Proteome ; Proteomics/methods ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects/*physiology/ultrastructure ; Trans-Activators/genetics ; Virulence Factors/genetics ; *beta-Lactam Resistance ; }, abstract = {Staphylococcus spp. play an important role in the etiology of bovine mastitis. Staphylococcus aureus is considered the most relevant species due to the production of virulence factors such as slime, which is required for biofilm formation. This study aimed to evaluate biofilm production and its possible relation to beta-lactamic resistance in 20 S. aureus isolates from bovine mastitic milk. The isolates were characterized by pheno-genotypic and MALDI TOF-MS assays and tested for genes such as icaA, icaD, bap, agr RNAIII, agr I, agr II, agr III, and agr IV, which are related to slime production and its regulation. Biofilm production in microplates was evaluated considering the intervals determined along the bacterial growth curve. In addition, to determine the most suitable time interval for biofilm analysis, scanning electron microscopy was performed. Furthermore, genes such as mecA and blaZ that are related to beta-lactamic resistance and oxacillin susceptibility were tested. All the studied isolates were biofilm producers and mostly presented icaA and icaD. The Agr type II genes were significantly prevalent. According to the SEM, gradual changes in the bacterial arrangement were observed during biofilm formation along the growth curve phases, and the peak was reached at the stationary phase. In this study, the penicillin resistance was related to the production of beta-lactamase, and the high minimal bactericidal concentration for cefoxitin was possibly associated with biofilm protection. Therefore, further studies are warranted to better understand biofilm formation, possibly contributing to our knowledge about bacterial resistance in vivo.}, } @article {pmid27910828, year = {2016}, author = {Howlin, RP and Winnard, C and Frapwell, CJ and Webb, JS and Cooper, JJ and Aiken, SS and Stoodley, P}, title = {Biofilm prevention of gram-negative bacterial pathogens involved in periprosthetic infection by antibiotic-loaded calcium sulfate beads in vitro.}, journal = {Biomedical materials (Bristol, England)}, volume = {12}, number = {1}, pages = {015002}, doi = {10.1088/1748-605X/12/1/015002}, pmid = {27910828}, issn = {1748-605X}, mesh = {Acinetobacter baumannii ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Calcium Sulfate/*chemistry ; Gram-Negative Bacteria/*drug effects ; Humans ; Klebsiella pneumoniae ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Prosthesis-Related Infections/drug therapy/*prevention & control ; Pseudomonas aeruginosa ; Tobramycin/pharmacology ; Vancomycin/pharmacology ; }, abstract = {Biofilm formation represents a key stage in the pathogenesis of prosthetic infections (PIs). More tolerant to antibiotics than their planktonic counterparts, biofilm bacteria are difficult to eradicate using conventional therapeutic regimes. A common approach in PI management is the adjunctive use of localised antibiotics in addition to systemic administration in an attempt to protect the implant from colonisation by infiltrating bacteria. This study evaluates the antibacterial and antibiofilm efficacy of antibiotic-loaded dissolvable calcium sulphate, previously shown to be effective against key gram-positive pathogens, against gram-negative species important in the establishment of chronic infection in PIs. Synthetic calcium sulfate beads loaded with tobramycin, vancomycin and both antibiotics in combination were assessed for their ability to eradicate planktonic Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae strains. The efficacy of the beads in preventing biofilm formation and eliminating established biofilms over multiple days was evaluated using confocal laser scanning microscopy (CSLM) imaging combined with image analysis and viable cell counts. Beads loaded with antibiotics demonstrated effective eluting concentrations for up to 37 d depending on the bacterial strain. In the presence of repeated bacterial challenges, antibiotic-loaded beads prevented bacterial colonisation and significantly reduce biofilm formation for the duration of the assay (7 d). Complete eradication of established biofilms was more difficult with evidence of biofilm regrowth after 1 week of contact with antibiotic-loaded beads, despite data suggesting a complete kill was achieved at earlier timepoints of 24 h and 72 h in the case of K. pneumoniae and P. aeruginosa. This study provides further evidence that calcium sulfate beads loaded with vancomycin and tobramycin may be a useful adjunctive component to the successful management of PIs.}, } @article {pmid27909688, year = {2016}, author = {Ding, Q and Tan, KS}, title = {The Danger Signal Extracellular ATP Is an Inducer of Fusobacterium nucleatum Biofilm Dispersal.}, journal = {Frontiers in cellular and infection microbiology}, volume = {6}, number = {}, pages = {155}, pmid = {27909688}, issn = {2235-2988}, mesh = {Adenosine Triphosphate/*metabolism ; *Bacterial Adhesion ; Biofilms/*drug effects ; Cells, Cultured ; *Endocytosis ; Fibroblasts/microbiology ; Fusobacterium nucleatum/*drug effects/pathogenicity/*physiology ; Humans ; Virulence ; Virulence Factors/biosynthesis ; }, abstract = {Plaque biofilm is the primary etiological agent of periodontal disease. Biofilm formation progresses through multiple developmental stages beginning with bacterial attachment to a surface, followed by development of microcolonies and finally detachment and dispersal from a mature biofilm as free planktonic bacteria. Tissue damage arising from inflammatory response to biofilm is one of the hallmark features of periodontal disease. A consequence of tissue damage is the release of ATP from within the cell into the extracellular space. Extracellular ATP (eATP) is an example of a danger associated molecular pattern (DAMP) employed by mammalian cells to elicit inflammatory and damage healing responses. Although, the roles of eATP as a signaling molecule in multi-cellular organisms have been relatively well studied, exogenous ATP also influences bacteria biofilm formation. Since plaque biofilms are continuously exposed to various stresses including exposure to the host damage factors such as eATP, we hypothesized that eATP, in addition to eliciting inflammation could potentially influence the biofilm lifecycle of periodontal associated bacteria. We found that eATP rather than nutritional factors or oxidative stress induced dispersal of Fusobacterium nucleatum, an organism associated with periodontal disease. eATP induced biofilm dispersal through chelating metal ions present in biofilm. Dispersed F. nucleatum biofilm, regardless of natural or induced dispersal by exogenous ATP, were more adhesive and invasive compared to planktonic or biofilm counterparts, and correspondingly activated significantly more pro-inflammatory cytokine production in infected periodontal fibroblasts. Dispersed F. nucleatum also showed higher expression of fadA, a virulence factor implicated in adhesion and invasion, compared to planktonic or biofilm bacteria. This study revealed for the first time that periodontal bacterium is capable of co-opting eATP, a host danger signaling molecule to detach from biofilms. Our results further showed that dispersed F. nucleatum possessed distinct virulence characteristics compared to their biofilm and planktonic counterparts.}, } @article {pmid27907861, year = {2017}, author = {Liu, BH and Yu, LC}, title = {In-situ, time-lapse study of extracellular polymeric substance discharge in Streptococcus mutans biofilm.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {150}, number = {}, pages = {98-105}, doi = {10.1016/j.colsurfb.2016.11.031}, pmid = {27907861}, issn = {1873-4367}, mesh = {Bacterial Adhesion ; *Biofilms ; Dental Caries/microbiology ; Dental Enamel/microbiology ; Extracellular Matrix/metabolism ; Humans ; Hydrogen-Ion Concentration ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Polymers/*chemistry ; Streptococcal Infections/*microbiology ; Streptococcus mutans/*physiology ; Surface Properties ; Tooth/microbiology ; }, abstract = {Streptococcus mutans is one of the main pathogens that cause tooth decay. By metabolizing carbohydrates, S. mutans emits extracellular polymeric substance (EPS) that adheres to the tooth surface and forms layers of biofilm. Periodontal disease occurs due to the low pH environment created by S. mutans biofilm, and such an acidic environment gradually erodes tooth enamel. Since the existence of EPS is essential in the formation of biofilm, the in-situ investigation of its generation and distribution in real time is the key to the control and suppression of S. mutans biofilm. Prior studies of the biofilm formation process by fluorescence microscope, scanning electron microscope, or spectroscope have roughly divided the mechanism into three stages: (1) initial attachment; (2) microcolonies; and (3) maturation. However, these analytical methods are incapable to observe real-time changes in different locations of the extracellular matrix, and to analyze mechanical properties for single bacteria in micro and nanoscale. Since atomic force microscopy (AFM) operates by precise control of tip-sample interaction forces in liquid and in air, living microorganisms can be analyzed under near-physiological conditions. Thus, analytical techniques based on AFM constitute powerful tools for the study of biological samples, both qualitatively and quantitatively. In this study, we used AFM to quantitatively track the changes of multiple nanomechanical properties of S. mutans, including dissipation energy, adhesion force, deformation, and elastic modulus at different metabolic stages. The data revealed that the bacterial extracellular matrix has a gradient distribution in stickiness, in which different stickiness indicates the variation of EPS compositions, freshness, and metabolic stages. In-situ, time-lapse AFM images showed the local generation and distribution of EPS at different times, in which the highest adhesion distributed along sides of the S. mutans cells. Through time-lapse analysis, we concluded that each contour layer is associated with a dynamic process of cell growth and nutrient consumption, and S. mutans is capable of controlling the priority of EPS secretion at specific locations. The live bacteria exhibited cyclic metabolic activities in the period of 23-34min at the maturation stage of biofilm formation. In addition, the discharge of EPS is responsive to the shear stress caused by the topographical change of biofilm to provide stronger mechanical support in the formation of 3D networked biofilm.}, } @article {pmid27907127, year = {2016}, author = {Afrooz, AR and Boehm, AB}, title = {Escherichia coli Removal in Biochar-Modified Biofilters: Effects of Biofilm.}, journal = {PloS one}, volume = {11}, number = {12}, pages = {e0167489}, pmid = {27907127}, issn = {1932-6203}, mesh = {*Biofilms ; *Charcoal/chemistry ; *Escherichia coli ; Filtration/*methods ; Waste Disposal, Fluid ; Water Microbiology ; Water Purification/*methods ; }, abstract = {The presence of microbial contaminants in urban stormwater is a significant concern for public health; however, their removal by traditional stormwater biofilters has been reported as inconsistent and inadequate. Recent work has explored the use of biochar to improve performance of stormwater biofilters under simplified conditions that do not consider potential effects of biofilm development on filter media. The present study investigates the role of biofilm on microbial contaminant removal performance of stormwater biofilters. Pseudomonas aeruginosa biofilms were formed in laboratory-scale sand and biochar-modified sand packed columns, which were then challenged with Escherichia coli laden synthetic stormwater containing natural organic matter. Results suggests that the presence of biofilm influences the removal of E. coli. However, the nature of the influence depends on the specific surface area and the relative hydrophobicity of filter media. The distribution of attached bacteria within the columns indicates that removal by filter media varies along the length of the column: the inlet was the primary removal zone regardless of experimental conditions. Findings from this research inform the design of field-scale biofilters for better and consistent performance in removing microbial contaminants from urban stormwater.}, } @article {pmid27907122, year = {2016}, author = {Alfonso-Gordillo, G and Flores-Ortiz, CM and Morales-Barrera, L and Cristiani-Urbina, E}, title = {Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays.}, journal = {PloS one}, volume = {11}, number = {12}, pages = {e0167494}, pmid = {27907122}, issn = {1932-6203}, mesh = {*Biodegradation, Environmental ; *Biofilms ; Biological Assay ; Biomass ; *Bioreactors ; Methyl Ethers/chemistry/*metabolism ; *Microbial Consortia ; }, abstract = {This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater.}, } @article {pmid27902776, year = {2016}, author = {Morici, P and Fais, R and Rizzato, C and Tavanti, A and Lupetti, A}, title = {Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0167470}, pmid = {27902776}, issn = {1932-6203}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/cytology/*drug effects/genetics/*physiology ; Cell Adhesion/drug effects ; Cyclic AMP/pharmacology ; Lactoferrin/*chemistry ; Morphogenesis/drug effects ; Peptide Fragments/*pharmacology ; Transcription, Genetic/drug effects ; }, abstract = {The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP) was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans.}, } @article {pmid27902758, year = {2016}, author = {Wajima, T and Anzai, Y and Yamada, T and Ikoshi, H and Noguchi, N}, title = {Oldenlandia diffusa Extract Inhibits Biofilm Formation by Haemophilus influenzae Clinical Isolates.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0167335}, pmid = {27902758}, issn = {1932-6203}, mesh = {Bacterial Proteins/antagonists & inhibitors ; Biofilms/*drug effects/*growth & development ; Carbon-Sulfur Lyases/antagonists & inhibitors ; Haemophilus influenzae/*drug effects/growth & development/metabolism/*physiology ; Humans ; Oldenlandia/*chemistry ; Plant Extracts/*pharmacology ; }, abstract = {Oldenlandia diffusa has been empirically used as a therapeutic adjunct for the treatment of respiratory infections. To establish the basic evidence of its clinical usefulness, antimicrobial and biofilm inhibitory activities of an O. diffusa extract were examined against clinical isolates of Haemophilus influenzae, a major causative pathogen of respiratory and sensory organ infections. No significant growth inhibitory activity was observed during incubation for more than 6 h after the extract addition into a culture of H. influenzae. On the other hand, biofilm formation by H. influenzae, evaluated by a crystal violet method, was significantly and dose-dependently inhibited by the O. diffusa extract. Furthermore, the mRNA level of the biofilm-associated gene luxS of H. influenzae significantly decreased soon after the extract addition, and the suppressive effect continued for at least 2 h. At 2 h after the addition of the O. diffusa extract, the autoinducer in the culture supernatant was also significantly reduced by the O. diffusa extract in a dose-dependent manner. These results revealed that O. diffusa extract shows inhibitory activity against luxS-dependent biofilm formation but has no antimicrobial activity against planktonic cells of H. influenzae. Thus, O. diffusa extract might be useful as an adjunctive therapy for the treatment of respiratory infections caused by H. influenzae.}, } @article {pmid27902688, year = {2016}, author = {Valentini, M and Laventie, BJ and Moscoso, JA and Jenal, U and Filloux, A}, title = {Correction: The Diguanylate Cyclase HsbD Intersects with the HptB Regulatory Cascade to Control Pseudomonas aeruginosa Biofilm and Motility.}, journal = {PLoS genetics}, volume = {12}, number = {11}, pages = {e1006473}, pmid = {27902688}, issn = {1553-7404}, support = {MR/J006874/1/MRC_/Medical Research Council/United Kingdom ; }, abstract = {[This corrects the article DOI: 10.1371/journal.pgen.1006354.].}, } @article {pmid27902411, year = {2016}, author = {Martínez-Reséndez, MF and González-Chávez, JM and Garza-González, E and Castro-Fuentes, LN and Gutiérrez-Ferman, JL and Echániz-Aviles, G and Camacho-Ortíz, A and Carnalla-Barajas, MN and Soto-Noguerón, A and Maldonado-Garza, HJ and Hernández-Balboa, CL and Llaca-Díaz, JM and Flores-Treviño, S}, title = {Non-typeable Haemophilus influenzae biofilm production and severity in lower respiratory tract infections in a tertiary hospital in Mexico.}, journal = {Journal of medical microbiology}, volume = {65}, number = {12}, pages = {1385-1391}, doi = {10.1099/jmm.0.000369}, pmid = {27902411}, issn = {1473-5644}, mesh = {Adolescent ; Adult ; Aged ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Bronchi/microbiology ; Comorbidity ; Female ; Genetic Variation ; Haemophilus Infections/epidemiology/*microbiology ; Haemophilus influenzae/classification/drug effects/genetics/*physiology ; Humans ; Length of Stay ; Male ; Mexico/epidemiology ; Microbial Sensitivity Tests ; Middle Aged ; Respiratory Tract Infections/epidemiology/*microbiology ; Serotyping ; Severity of Illness Index ; Sputum/microbiology ; Tertiary Care Centers ; Trachea/microbiology ; Young Adult ; beta-Lactamases/biosynthesis ; }, abstract = {Non-typeable Haemophilus influenzae (NTHi) is a common opportunistic bacterial pathogen that primarily infects the respiratory mucosa. This study was conducted to assess clinical and microbiological data related to disease severity in patients with lower respiratory tract infections caused by NTHi in a tertiary care hospital in Mexico. NTHi isolates were subjected to serotyping, antimicrobial susceptibility evaluationand analyses of β-lactamase production, genetic relatednessand biofilm formation. Clinical and demographic data were retrieved from patients' records. The mean age of the patients was 40.3 years; the majority (n=44, 72.1 %) were male. The main comorbidities were arterial hypertension (n=22, 36.1 %) and diabetes mellitus (n=17, 27.9 %). NTHi isolates (n=98) were recovered from tracheal aspirate (n=57, 58.2 %), sputum (n=26, 26.5 %)and bronchial aspirate (n=15, 15.3 %) specimens. Low resistance to cefotaxime (n=0, 0.0 %), rifampin (n=1, 1.1 %) and chloramphenicol (n=3, 3.2 %) and greater resistance to ampicillin (n=30, 32.3 %) and trimethoprim-sulfamethoxazole (n=49, 52.7 %) were detected. β-Lactamase production was found in 17 (17.3 %) isolates. Isolates displayed high genetic diversity, and only 10 (10.2 %) were found to be biofilm producers. The antimicrobial susceptibility patterns of biofilm-producing and non-producing isolates did not differ. Biofilm production was associated with prolonged hospital stay (P=0.05). Lower respiratory NTHi isolates from Mexico showed low antimicrobial resistance and weak biofilm production. Younger age was correlated with lower Acute Physiology and Chronic Health Evaluation II score (moderate, P=0.07; severe, P=0.03).}, } @article {pmid27902401, year = {2017}, author = {Ou, Q and Fan, J and Duan, D and Xu, L and Wang, J and Zhou, D and Yang, H and Li, B}, title = {Involvement of cAMP receptor protein in biofilm formation, fimbria production, capsular polysaccharide biosynthesis and lethality in mouse of Klebsiella pneumoniae serotype K1 causing pyogenic liver abscess.}, journal = {Journal of medical microbiology}, volume = {66}, number = {1}, pages = {1-7}, doi = {10.1099/jmm.0.000391}, pmid = {27902401}, issn = {1473-5644}, mesh = {Animals ; Bacterial Capsules/metabolism ; Bacterial Proteins/genetics/*metabolism ; Biofilms/growth & development ; Cyclic AMP Receptor Protein/genetics/*metabolism ; Female ; Fimbriae, Bacterial/*metabolism ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Klebsiella pneumoniae/genetics/metabolism/*pathogenicity ; Liver Abscess, Pyogenic/*microbiology/pathology ; Mice ; Mice, Inbred BALB C ; Polysaccharides, Bacterial ; RNA, Bacterial/genetics ; Serotyping ; Virulence ; }, abstract = {The global regulator cAMP receptor protein (CRP) has been shown to be required for the full virulence and/or for the expression of virulence determinants in a wide set of bacterial pathogens. In this work, the crp mutant as well as the complemented mutant was constructed from a wild-type Klebsiella pneumoniae capsular serotype K1 strain causing the primary pyogenic liver abscess. The phenotypes of wild-type strain, crp mutant and complemented mutant were characterized systematically. It was disclosed that K. pneumoniae CRP was required for the in vitro growth, fimbria production, biofilm formation and lethality in mouse, but it inhibited the capsular polysaccharide biosynthesis. These indicated the important roles of CRP in regulating the expression of virulence and biofilm genes in K. pneumoniae.}, } @article {pmid27902368, year = {2016}, author = {Szczuka, E and Jabłońska, L and Kaznowski, A}, title = {Coagulase-negative staphylococci: pathogenesis, occurrence of antibiotic resistance genes and in vitro effects of antimicrobial agents on biofilm-growing bacteria.}, journal = {Journal of medical microbiology}, volume = {65}, number = {12}, pages = {1405-1413}, doi = {10.1099/jmm.0.000372}, pmid = {27902368}, issn = {1473-5644}, mesh = {Aminoglycosides/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Coagulase/*metabolism ; Drug Resistance, Multiple, Bacterial/genetics ; HeLa Cells ; Humans ; Lincosamides/pharmacology ; Microbial Sensitivity Tests ; Operon ; Rifampin/pharmacology ; Staphylococcal Infections/microbiology ; Staphylococcus/drug effects/enzymology/*genetics/*pathogenicity ; Virulence ; }, abstract = {Coagulase-negative staphylococci (CoNS) are opportunistic pathogens that particularly cause infections in patients with implanted medical devices. The present research was performed to study the virulence potential of 53 clinical isolates of Staphylococcus capitis, Staphylococcus auricularis, Staphylococcus lugdunensis, Staphylococcus simulans, Staphylococcus cohnii and Staphylococcus caprae. All clinical strains were clonally unrelated. Isolates carried genes encoding resistance to β-lactam (mecA) (15 %), aminoglycoside [aac(6')/aph(2″)(11 %), aph (3')-IIIa (15 %), ant(4')-Ia (19 %)] and macrolide, lincosamide and streptogramin B (MLSB) [erm(A) (4 %), erm(B) (13 %), erm(C) (41 %), msr(A) (11 %)] antibiotics. CoNS isolates (64 %) were able to form biofilms. Confocal laser scanning microscopy revealed that these biofilms formed a three-dimensional structure composed mainly of living cells. All biofilm-positive strains carried the ica operon. In vitro studies demonstrated that a combination treatment with tigecycline and rifampicin was more effective against biofilms than one with ciprofloxacin and rifampicin. The minimum biofilm eradication concentration values were 0.062-0.5 µg ml-1 for tigecycline/rifampicin and 0.250-2 µg ml-1 for ciprofloxacin/rifampicin. All CoNS strains adhered to the human epithelial cell line HeLa, and more than half of the isolates were able to invade the HeLa cells, although most invaded relatively poorly. The virulence of CoNS is also attributed to their cytotoxic effects on HeLa cells. Incubation of HeLa cells with culture supernatant of the CoNS isolates resulted in cell death. The results indicate that the pathogenicity of S. capitis, S. auricularis, S. lugdunensis, S. cohnii and S. caprae is multi-factorial, involving the ability of these bacteria to adhere to human epithelial cells, form biofilms and invade and destroy human cells.}, } @article {pmid27900438, year = {2017}, author = {Liu, T and Mao, YJ and Shi, YP and Quan, X}, title = {Start-up and bacterial community compositions of partial nitrification in moving bed biofilm reactor.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {6}, pages = {2563-2574}, doi = {10.1007/s00253-016-8003-9}, pmid = {27900438}, issn = {1432-0614}, mesh = {Ammonia/*metabolism ; Bacteria/classification/*genetics/metabolism ; Biofilms/*growth & development ; Bioreactors ; Comamonas/growth & development/metabolism ; High-Throughput Nucleotide Sequencing ; Humans ; Microbial Consortia/physiology ; Nitrification ; Nitrosomonas/growth & development/metabolism ; Oxidation-Reduction ; *Phylogeny ; Waste Disposal, Fluid ; Wastewater/*microbiology ; }, abstract = {Partial nitrification (PN) has been considered as one of the promising processes for pretreatment of ammonium-rich wastewater. In this study, a kind of novel carriers with enhanced hydrophilicity and electrophilicity was implemented in a moving bed biofilm reactor (MBBR) to start up PN process. Results indicated that biofilm formation rate was higher on modified carriers. In comparison with the reactor filled with traditional carriers (start-up period of 21 days), it took only 14 days to start up PN successfully with ammonia removal efficiency and nitrite accumulation rate of 90 and 91%, respectively, in the reactor filled with modified carriers. Evident changes of spatial distributions and community structures had been detected during the start-up. Free-floating cells existed in planktonic sludge, while these microorganisms trended to form flocs in the biofilm. High-throughput pyrosequencing results indicated that Nitrosomonas was the predominant ammonia-oxidizing bacterium (AOB) in the PN system, while Comamonas might also play a vital role for nitrogen oxidation. Additionally, some other bacteria such as Ferruginibacter, Ottowia, Saprospiraceae, and Rhizobacter were selected to establish stable footholds. This study would be potentially significant for better understanding the microbial features and developing efficient strategies accordingly for MBBR-based PN operation.}, } @article {pmid27900265, year = {2017}, author = {Dees, MW and Brurberg, MB and Lysøe, E}, title = {Complete genome sequence of the biofilm-forming Microbacterium sp. strain BH-3-3-3, isolated from conventional field-grown lettuce (Lactuca sativa) in Norway.}, journal = {Genomics data}, volume = {11}, number = {}, pages = {7-8}, pmid = {27900265}, issn = {2213-5960}, abstract = {The genus Microbacterium contains bacteria that are ubiquitously distributed in various environments and includes plant-associated bacteria that are able to colonize tissue of agricultural crop plants. Here, we report the 3,508,491 bp complete genome sequence of Microbacterium sp. strain BH-3-3-3, isolated from conventionally grown lettuce (Lactuca sativa) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017674.}, } @article {pmid27899451, year = {2017}, author = {Nair, HA and Periasamy, S and Yang, L and Kjelleberg, S and Rice, SA}, title = {Real Time, Spatial, and Temporal Mapping of the Distribution of c-di-GMP during Biofilm Development.}, journal = {The Journal of biological chemistry}, volume = {292}, number = {2}, pages = {477-487}, pmid = {27899451}, issn = {1083-351X}, mesh = {Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/genetics/metabolism ; Green Fluorescent Proteins/genetics/metabolism ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a dynamic intracellular signaling molecule that plays a central role in the biofilm life cycle. Current methodologies for the quantification of c-di-GMP are typically based on chemical extraction, representing end point measurements. Chemical methodologies also fail to take into consideration the physiological heterogeneity of the biofilm and thus represent an average c-di-GMP concentration across the entire biofilm. To address these problems, a ratiometric, image-based quantification method has been developed based on expression of the green fluorescence protein (GFP) under the control of the c-di-GMP-responsive cdrA promoter (Rybtke, M. T., Borlee, B. R., Murakami, K., Irie, Y., Hentzer, M., Nielsen, T. E., Givskov, M., Parsek, M. R., and Tolker-Nielsen, T. (2012) Appl. Environ. Microbiol. 78, 5060-5069). The methodology uses the cyan fluorescent protein (CFP) as a biomass indicator and the GFP as a c-di-GMP reporter. Thus, the CFP/GFP ratio gives the effective c-di-GMP per biomass. A binary mask was applied to alleviate background fluorescence, and fluorescence was calibrated against known c-di-GMP concentrations. Using flow cells for biofilm formation, c-di-GMP showed a non-uniform distribution across the biofilm, with concentrated hot spots of c-di-GMP. Additionally, c-di-GMP was found to be localized at the outer boundary of mature colonies in contrast to a uniform distribution in early stage, small colonies. These data demonstrate the application of a method for the in situ, real time quantification of c-di-GMP and show that the amount of this biofilm-regulating second messenger was dynamic with time and colony size, reflecting the extent of biofilm heterogeneity in real time.}, } @article {pmid27896598, year = {2017}, author = {Perez-Jorge, C and Arenas, MA and Conde, A and Hernández-Lopez, JM and de Damborenea, JJ and Fisher, S and Hunt, AM and Esteban, J and James, G}, title = {Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.}, journal = {Journal of materials science. Materials in medicine}, volume = {28}, number = {1}, pages = {8}, pmid = {27896598}, issn = {1573-4838}, mesh = {Alloys/chemistry ; Anti-Bacterial Agents/chemistry ; Biofilms/*drug effects ; Candida albicans ; Escherichia coli ; Fluorine/*chemistry ; Microbial Sensitivity Tests ; Nanostructures/chemistry ; Nanotubes/chemistry ; Orthopedics ; Porosity ; Pseudomonas aeruginosa ; Staphylococcus aureus ; Staphylococcus epidermidis ; Titanium/*chemistry ; }, abstract = {Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.}, } @article {pmid27892814, year = {2017}, author = {Alijani Ardeshir, R and Rastgar, S and Peyravi, M and Jahanshahi, M and Shokuhi Rad, A}, title = {A new route of bioaugmentation by allochthonous and autochthonous through biofilm bacteria for soluble chemical oxygen demand removal of old leachate.}, journal = {Environmental technology}, volume = {38}, number = {19}, pages = {2447-2455}, doi = {10.1080/09593330.2016.1264488}, pmid = {27892814}, issn = {1479-487X}, mesh = {*Bacteria ; *Biodegradation, Environmental ; *Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; Sewage ; Water Pollutants, Chemical ; }, abstract = {Landfill leachate contains environmental pollutants that are generally resistant to biodegradation. In this study, indigenous and exogenous bacteria in leachate were acclimated in both biofilm and suspension forms to increase the removal of soluble chemical oxygen demand (SCOD). The bacteria from the leachate and sewage were acclimated to gradually increasing leachate concentration prepared using a reverse osmosis membrane over 28 days. The SCOD removal was measured aerobically or nominally anaerobically. Biofilms were prepared using different carrier media (glass, rubber, and plastic). The maximum SCOD removal in suspensions was 32% (anaerobic) and in biofilms was 39% (aerobic). In the suspension form, SCOD removal using acclimated bacteria from leachate and sewage anaerobically increased in comparison with the control (P < .05). In the biofilm form, the aerobic condition and the use of acclimated bacteria from leachate and sewage increased the removal efficiency of SCOD in comparison with other biofilm groups (P < .05). Three species of bacteria, including Bacillus cereus, Bacillus subtilis, and Pseudomonas aeruginosa were identified in the biofilm from leachate and sewage. Bioaugmentation technology using biofilms and acclimations can be an effective, inexpensive, and simple way to decrease SCOD in old landfill leachate.}, } @article {pmid27892689, year = {2017}, author = {Kubera, A and Thamchaipenet, A and Shoham, M}, title = {Biofilm inhibitors targeting the outer membrane protein A of Pasteurella multocida in swine.}, journal = {Biofouling}, volume = {33}, number = {1}, pages = {14-23}, doi = {10.1080/08927014.2016.1259415}, pmid = {27892689}, issn = {1029-2454}, mesh = {Amino Acid Sequence ; Animals ; Bacterial Outer Membrane Proteins/*antagonists & inhibitors/chemistry/genetics ; Biofilms/*drug effects/growth & development ; Indocyanine Green/*pharmacology ; Models, Biological ; Models, Molecular ; Mycophenolic Acid/*pharmacology ; Pasteurella Infections/drug therapy/*microbiology ; Pasteurella multocida/*drug effects/metabolism/pathogenicity/physiology ; Protein Binding ; Rhinitis, Atrophic/drug therapy/*microbiology ; Swine ; Virulence ; Virulence Factors/metabolism ; }, abstract = {Pasteurella multocida (Pm) is the causative agent of atrophic rhinitis in swine. This study aimed to discover biofilm inhibitors against swine Pm to counteract antibiotic resistance and decrease virulence. The virulence factor outer membrane protein A (OmpA) was targeted. A library of drugs approved by the Food and Drug Administration (FDA) was used to perform virtual screening against PmOmpA. The top-scoring compounds had no effect on the growth of Pm serotype A or D. Mycophenolate mofetil showed the highest efficacy in inhibiting biofilm formation by Pm serotype A, with an IC50 of 7.3 nM. For Pm serotype D, indocyanine green showed the highest effect at an IC50 of 11.7 nM. Nevertheless, these compounds had no effect on an established biofilm of Pm. This study offers an alternative way to prevent biofilm formation by Pm that could also be applied to other pathogens.}, } @article {pmid27891125, year = {2016}, author = {Yu, Y and Yan, F and Chen, Y and Jin, C and Guo, JH and Chai, Y}, title = {Poly-γ-Glutamic Acids Contribute to Biofilm Formation and Plant Root Colonization in Selected Environmental Isolates of Bacillus subtilis.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1811}, pmid = {27891125}, issn = {1664-302X}, abstract = {Bacillus subtilis is long known to produce poly-γ-glutamic acids (γ-PGA) as one of the major secreted polymeric substances. In B. subtilis, the regulation of γ-PGA production and its physiological role are still unclear. B. subtilis is also capable of forming structurally complex multicellular communities, or biofilms, in which an extracellular matrix consisting of secreted proteins and polysaccharides holds individual cells together. Biofilms were shown to facilitate B. subtilis-plant interactions. In this study, we show that different environmental isolates of B. subtilis, all capable of forming biofilms, vary significantly in γ-PGA production. This is possibly due to differential regulation of γ-PGA biosynthesis genes. In many of those environmental isolates, γ-PGA seems to contribute to robustness and complex morphology of the colony biofilms, suggesting a role of γ-PGA in biofilm formation. Our evidence further shows that in selected B. subtilis strains, γ-PGA also plays a role in root colonization by the bacteria, pinpointing a possible function of γ-PGA in B. subtilis-plant interactions. Finally, we found that several pathways co-regulate both γ-PGA biosynthesis genes and genes for the biofilm matrix in B. subtilis, but in an opposing fashion. We discussed potential biological significance of that.}, } @article {pmid27891050, year = {2016}, author = {Gupta, S and Laskar, N and Kadouri, DE}, title = {Evaluating the Effect of Oxygen Concentrations on Antibiotic Sensitivity, Growth, and Biofilm Formation of Human Pathogens.}, journal = {Microbiology insights}, volume = {9}, number = {}, pages = {37-46}, pmid = {27891050}, issn = {1178-6361}, abstract = {Standard antimicrobial susceptibility tests are performed in vitro under normal room oxygen conditions to predict the in vivo effectiveness of antimicrobial therapy. The aim of this study was to conduct a comprehensive analysis of the effect of different oxygen levels on the antibiotic susceptibility of two strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. It was found that anoxic conditions caused reduced sensitivity of bacteria to aminoglycoside antibiotics in four of six bacteria used in the study. In addition, oxygen limitation decreased the susceptibility of P. aeruginosa strains and K. pneumoniae strains to piperacillin/tazobactam and azithromycin, respectively. In contrast, five of six bacteria became more susceptible to tetracycline antibiotics under oxygen-limiting conditions. Our data highlight the importance of considering the potential in vivo oxygen levels within the infection site when setting susceptibility breakpoints for evaluating the therapeutic potential of a drug and its effect on antibiotic sensitivity of the pathogen.}, } @article {pmid27890783, year = {2017}, author = {Yarawsky, AE and English, LR and Whitten, ST and Herr, AB}, title = {The Proline/Glycine-Rich Region of the Biofilm Adhesion Protein Aap Forms an Extended Stalk that Resists Compaction.}, journal = {Journal of molecular biology}, volume = {429}, number = {2}, pages = {261-279}, pmid = {27890783}, issn = {1089-8638}, support = {R01 GM094363/GM/NIGMS NIH HHS/United States ; R15 GM115603/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Bacterial Adhesion ; Bacterial Proteins/*chemistry/genetics ; *Biofilms ; Glycine/*chemistry ; Methylamines ; Proline/*chemistry ; Staphylococcus epidermidis/chemistry/genetics ; Trifluoroethanol ; Virulence Factors/chemistry/genetics ; }, abstract = {Staphylococcus epidermidis is one of the primary bacterial species responsible for healthcare-associated infections. The most significant virulence factor for S. epidermidis is its ability to form a biofilm, which renders the bacteria highly resistant to host immune responses and antibiotic action. Intercellular adhesion within the biofilm is mediated by the accumulation-associated protein (Aap), a cell wall-anchored protein that self-assembles in a zinc-dependent manner. The C-terminal portion of Aap contains a 135-aa-long, proline/glycine-rich region (PGR) that has not yet been characterized. The region contains a set of 18 nearly identical AEPGKP repeats. Analysis of the PGR using biophysical techniques demonstrated the region is a highly extended, intrinsically disordered polypeptide with unusually high polyproline type II helix propensity. In contrast to many intrinsically disordered polypeptides, there was a minimal temperature dependence of the global conformational state of PGR in solution as measured by analytical ultracentrifugation and dynamic light scattering. Furthermore, PGR was resistant to conformational collapse or α-helix formation upon the addition of the osmolyte trimethylamine N-oxide or the cosolvent 2,2,2-trifluoroethanol. Collectively, these results suggest PGR functions as a resilient, extended stalk that projects the rest of Aap outward from the bacterial cell wall, promoting intercellular adhesion between cells in the biofilm. This work sheds light on regions of low complexity often found near the attachment point of bacterial cell wall-anchored proteins.}, } @article {pmid27890730, year = {2017}, author = {Canty, M and Luke-Marshall, N and Campagnari, A and Ehrensberger, M}, title = {Cathodic voltage-controlled electrical stimulation of titanium for prevention of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii biofilm infections.}, journal = {Acta biomaterialia}, volume = {48}, number = {}, pages = {451-460}, doi = {10.1016/j.actbio.2016.11.056}, pmid = {27890730}, issn = {1878-7568}, support = {UL1 TR001412/TR/NCATS NIH HHS/United States ; }, mesh = {Acinetobacter Infections/microbiology/*prevention & control ; Acinetobacter baumannii/drug effects/growth & development/*physiology ; Biofilms/*drug effects ; Colony Count, Microbial ; Electric Stimulation ; Electricity ; Electrochemical Techniques ; Electrodes ; Hydrogen-Ion Concentration ; Methicillin-Resistant Staphylococcus aureus/drug effects/growth & development/*physiology ; Staphylococcal Infections/microbiology/*prevention & control ; Titanium/*pharmacology ; }, abstract = {UNLABELLED: Antibiotic resistance of bacterial biofilms limits available treatment methods for implant-associated orthopaedic infections. This study evaluated the effects of applying cathodic voltage-controlled electrical stimulations (CVCES) of -1.5V and -1.8V (vs. Ag/AgCl) to coupons of commercially pure titanium (cpTi) incubated in cultures of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (A. baumannii) as a method of preventing bacterial attachment. Stimulations were applied for 2, 4, and 8h and coupon-associated and planktonic colony-forming units (CFU) were enumerated following stimulation. Compared to open circuit potential (OCP) controls, CVCES for 4h at -1.8V significantly reduced coupon-associated MRSA CFU by 99.9% (1.30×10[4]vs. 4.45×10[7], p=0.047) and A. baumannii coupon-associated CFU by 99.9% (1.64×10[4]vs. 5.93×10[7], p=0.001) and reduced planktonic CFU below detectable levels for both strains. CVCES at -1.8V for 8h also reduced coupon-associated and planktonic CFU below detectable levels for each strain. CVCES at -1.5V for 4 and 8h, and -1.8V for 2h did not result in clinically relevant reductions. For 4 and 8h stimulations, the current density was significantly higher for -1.8V than -1.5V, an effect directly related to the rate of water and oxygen reduction on the cpTi surface. This significantly increased the pH, a suspected influence in decreased CFU viability. The voltage-dependent electrochemical properties of cpTi likely contribute to the observed antimicrobial effects of CVCES. This study revealed that CVCES of titanium could prevent coupon-associated and planktonic CFU of Gram-positive MRSA and Gram-negative A. baumannii from reaching detectable levels in a magnitude-dependent and time-dependent manner.

STATEMENT OF SIGNIFICANCE: Periprosthetic joint infection is a devastating outcome of total joint arthroplasty and has led to increased patient morbidity and rising healthcare costs. Current treatments are limited by the growing prevalence of antimicrobial resistant biofilms. Therefore, there is a growing interest in the prevention of bacterial colonization of implants. Previous work has shown that cathodic voltage-controlled electrical stimulation (CVCES) of titanium is effective both in vitro and in vivo as an antimicrobial strategy to eradicate established implant-associated biofilm infections. The present study revealed that CVCES of titanium coupons also has utility in preventing coupon-associated and planktonic colony-forming units of Gram-positive methicillin-resistant Staphylococcus aureus and Gram-negative Acinetobacter baumannii from reaching detectable levels in a magnitude-dependent and time-dependent manner.}, } @article {pmid27890651, year = {2017}, author = {Isiaku, AI and Sabri, MY and Ina-Salwany, MY and Hassan, MD and Tanko, PN and Bello, MB}, title = {Biofilm is associated with chronic streptococcal meningoencephalitis in fish.}, journal = {Microbial pathogenesis}, volume = {102}, number = {}, pages = {59-68}, doi = {10.1016/j.micpath.2016.10.029}, pmid = {27890651}, issn = {1096-1208}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Autopsy ; *Biofilms ; Chronic Disease ; Drug Resistance, Bacterial ; Fish Diseases/diagnosis/*microbiology ; Fishes ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Meningoencephalitis/*veterinary ; Microbial Sensitivity Tests ; Phenotype ; Streptococcal Infections/*veterinary ; Streptococcus/drug effects/*physiology ; Streptococcus agalactiae/drug effects ; Tilapia ; }, abstract = {Biofilms are aggregates of attached microbial organisms whose existence on tissues is often recognised as a mechanism for the establishment of most chronic diseases. Herein we investigated the ability of piscine Streptococcus agalactiae, an important aquatic pathogen, for adaptation to this sessile lifestyle in vitro and in the brain of a tilapia fish model. Piscine S. agalactiae exhibited a weak attachment to polystyrene plates and expressed a low biofilm phenotype under the study conditions. Furthermore, fluorescent in situ hybridization and confocal laser scanning microscopy revealed discrete aggregates of attached S. agalactiae within brain tissues and around meningeal surfaces. They were embedded in an exopolysaccharide containing matrix, intractable to inflammatory response and showed some level of resistance to penicillin despite proven susceptibility on sensitivity test. Intracellular bacterial aggregates were also observed, moreover, antibody mediated response was not demonstrated during infection. Nucleated erythrocytes appear to facilitate brain invasion possibly via the Trojan horse mechanism leading to a granulomatous inflammation. We have demonstrated that biofilm is associated with persistence of S. agalactiae and the development of chronic meningoencephalitis in fish.}, } @article {pmid27890366, year = {2016}, author = {Yılmaz, ES and Güvensen, NC}, title = {In vitro biofilm formation in ESBL producing Escherichia coli isolates from cage birds.}, journal = {Asian Pacific journal of tropical medicine}, volume = {9}, number = {11}, pages = {1069-1074}, doi = {10.1016/j.apjtm.2016.10.003}, pmid = {27890366}, issn = {2352-4146}, abstract = {OBJECTIVE: To determine biofilm and hydrophobicity formation ratios in extended spectrum beta lactamases (ESBL) synthesizing Escherichia coli isolates which were isolated from feces samples of 150 cage bird species randomly taken from pet shops in Hatay province, Turkey.

METHODS: In vitro biofilm production of 4 ESBL positive isolates were performed by Congo Red Agar (CRA), Standard Tube (ST) and Microtitre Plate (MP) methods while their hydrophobicity were examined by bacterial adhesion to hydrocarbon (BATH) test.

RESULTS: In the examined isolates, while biofilm production was found to be negative by CRA method, highest biofilm producing strain, among 4 bacteria was determined to be A42 by ST and MP methods. The Scanning Electron Microscopy (SEM) also displayed these confirmed findings. The hydrophobicity values of strains were determined to be between 22.45% and 26.42%.

CONCLUSIONS: As a result, biofilm formation in cage bird feces originated ESBL positive Escherichia coli isolates was performed for the first time in Turkey. In order to present the relation between pathogenicity and biofilm production in animal originated ESBL positive isolates, further studies are required.}, } @article {pmid27890003, year = {2017}, author = {Kanwar, I and Sah, AK and Suresh, PK}, title = {Biofilm-mediated Antibiotic-resistant Oral Bacterial Infections: Mechanism and Combat Strategies.}, journal = {Current pharmaceutical design}, volume = {23}, number = {14}, pages = {2084-2095}, doi = {10.2174/1381612822666161124154549}, pmid = {27890003}, issn = {1873-4286}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Infections/*drug therapy ; Biofilms/drug effects ; Dental Caries/*drug therapy/microbiology ; Drug Resistance, Bacterial/drug effects ; Gram-Negative Bacteria/drug effects ; Humans ; Microbial Sensitivity Tests ; Periodontal Diseases/*drug therapy/microbiology ; }, abstract = {Oral diseases like dental caries and periodontal disease are directly associated with the capability of bacteria to form biofilm. Periodontal diseases have been associated to anaerobic Gram-negative bacteria forming a subgingival plaque (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Biofilm is a complex bacterial community that is highly resistant to antibiotics and human immunity. Biofilm communities are the causative agents of biological developments such as dental caries, periodontitis, peri-implantitis and causing periodontal tissue breakdown. The review recapitulates the latest advancements in treatment of clinical biofilm infections and scientific investigations, while these novel anti-biofilm strategies are still in nascent phases of development, efforts dedicated to these technologies could ultimately lead to anti-biofilm therapies that are superior to the current antibiotic treatment. This paper provides a review of the literature focusing on the studies on biofilm in the oral cavity, formation of dental plaque biofilm, drug resistance of bacterial biofilm and the antibiofilm approaches as biofilm preventive agents in dentistry, and their mechanism of biofilm inhibition.}, } @article {pmid27889168, year = {2017}, author = {Ng, CG and Loke, MF and Goh, KL and Vadivelu, J and Ho, B}, title = {Biofilm formation enhances Helicobacter pylori survivability in vegetables.}, journal = {Food microbiology}, volume = {62}, number = {}, pages = {68-76}, doi = {10.1016/j.fm.2016.10.010}, pmid = {27889168}, issn = {1095-9998}, mesh = {Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Brassica/microbiology ; *Food Microbiology ; Helicobacter pylori/*physiology ; Humans ; Microbial Viability ; Plant Leaves/microbiology ; Plant Stomata/microbiology ; Vegetables/*microbiology ; }, abstract = {To date, the exact route and mode of transmission of Helicobacter pylori remains elusive. The detection of H. pylori in food using molecular approaches has led us to postulate that the gastric pathogen may survive in the extragastric environment for an extended period. In this study, we show that H. pylori prolongs its survival by forming biofilm and micro-colonies on vegetables. The biofilm forming capability of H. pylori is both strain and vegetable dependent. H. pylori strains were classified into high and low biofilm formers based on their highest relative biofilm units (BU). High biofilm formers survived longer on vegetables compared to low biofilm formers. The bacteria survived better on cabbage compared to other vegetables tested. In addition, images captured on scanning electron and confocal laser scanning microscopes revealed that the bacteria were able to form biofilm and reside as micro-colonies on vegetable surfaces, strengthening the notion of possible survival of H. pylori on vegetables for an extended period of time. Taken together, the ability of H. pylori to form biofilm on vegetables (a common food source for human) potentially plays an important role in its survival, serving as a mode of transmission of H. pylori in the extragastric environment.}, } @article {pmid27888915, year = {2017}, author = {Zhao, YC and Wormald, PJ}, title = {Biofilm and Osteitis in Refractory Chronic Rhinosinusitis.}, journal = {Otolaryngologic clinics of North America}, volume = {50}, number = {1}, pages = {49-60}, doi = {10.1016/j.otc.2016.08.005}, pmid = {27888915}, issn = {1557-8259}, mesh = {*Biofilms/drug effects/growth & development ; Chronic Disease ; Disease Management ; Humans ; Nasal Bone/*pathology ; *Osteitis/immunology/physiopathology/surgery ; Prognosis ; *Rhinitis/diagnosis/physiopathology ; *Sinusitis/diagnosis/physiopathology/therapy ; }, abstract = {Our understanding of chronic rhinosinusitis (CRS) show biofilm and osteitis play a role in the disease's pathogenesis and refractory. Studies point to its role in pathogenesis and poor prognosis. Outside the research laboratory, biofilm detection remains difficult and specific treatment remains elusive. It is believed that osteitis is a nidus of inflammation and occurs more commonly in patients with refractory CRS. However, osteitis may be exacerbated by surgery and a marker of refractory disease, not a causative agent. Surgery remains the mainstay treatment for biofilm and osteitis with mechanical disruption and removal of disease load providing the most effective treatment.}, } @article {pmid27885605, year = {2017}, author = {King, RM and Korolik, V}, title = {Characterization of Ligand-Receptor Interactions: Chemotaxis, Biofilm, Cell Culture Assays, and Animal Model Methodologies.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1512}, number = {}, pages = {149-161}, doi = {10.1007/978-1-4939-6536-6_13}, pmid = {27885605}, issn = {1940-6029}, mesh = {Agglutination Tests ; Animals ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; *Biological Assay ; Campylobacter Infections/microbiology/*veterinary ; Campylobacter jejuni/pathogenicity/*physiology ; Chemotaxis/genetics ; Chickens ; Gene Expression ; Ligands ; Poultry Diseases/*microbiology ; Protein Binding ; Receptors, Cell Surface/genetics/metabolism ; }, abstract = {Chemotactic motility is an essential virulence factor for the pathogenesis of Campylobacter spp. infection. In Chapter 6 , we described technologies that enable initial screening and identification of ligands able to interact with chemoreceptor sensory domains. These include amino acid and glycan arrays, NMR, and SPR that are utilized to identify potential ligands interacting with Campylobacter jejuni. Here we describe techniques that enable the characterization and evaluation of ligand-receptor binding in chemotaxis through the assessment of motility and directed chemotactic motility as well as the associated phenotypes-autoagglutination behavior, biofilm formation, ability to adhere and invade cultured mammalian cells, and colonization ability in avian hosts.}, } @article {pmid27884783, year = {2017}, author = {Bay, DC and Stremick, CA and Slipski, CJ and Turner, RJ}, title = {Secondary multidrug efflux pump mutants alter Escherichia coli biofilm growth in the presence of cationic antimicrobial compounds.}, journal = {Research in microbiology}, volume = {168}, number = {3}, pages = {208-221}, doi = {10.1016/j.resmic.2016.11.003}, pmid = {27884783}, issn = {1769-7123}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Outer Membrane Proteins/genetics ; Benzalkonium Compounds/pharmacology ; Biofilms/*drug effects/growth & development ; Cations ; *Drug Resistance, Multiple, Bacterial/genetics ; Escherichia coli/*genetics/growth & development ; *Gene Deletion ; Membrane Transport Proteins/*genetics/metabolism ; Microbial Sensitivity Tests ; Mutation ; Phenotype ; Plankton ; }, abstract = {Escherichia coli possesses many secondary active multidrug resistance transporters (MDTs) that confer overlapping substrate resistance to a broad range of antimicrobials via proton and/or sodium motive force. It is uncertain whether redundant MDTs uniquely alter cell survival when cultures grow planktonically or as biofilms. In this study, the planktonic and biofilm growth and antimicrobial resistance of 13 E. coli K-12 single MDT gene deletion strains in minimal and rich media were determined. Antimicrobial tolerance to tetracycline, tobramycin and benzalkonium were also compared for each ΔMDT strain. Four E. coli MDT families were represented in this study: resistance nodulation and cell division members acrA, acrB, acrD, acrE, acrF and tolC; multidrug and toxin extruder mdtK; major facilitator superfamily emrA and emrB; and small multidrug resistance members emrE, sugE, mdtI and mdtJ. Deletions of multipartite efflux system genes acrB, acrE and tolC resulted in significant reductions in both planktonic and biofilm growth phenotypes and enhanced antimicrobial susceptibilities. The loss of remaining MDT genes produced similar or enhanced (acrD, acrE, emrA, emrB, mdtK, emrE and mdtJ) biofilm growth and antimicrobial resistance. ΔMDT strains with enhanced antimicrobial tolerance also enhanced biofilm biomass. These findings suggest that many redundant MDTs regulate biofilm formation and drug tolerance.}, } @article {pmid27882771, year = {2017}, author = {Yaniv, K and Golberg, K and Kramarsky-Winter, E and Marks, R and Pushkarev, A and Béjà, O and Kushmaro, A}, title = {Functional marine metagenomic screening for anti-quorum sensing and anti-biofilm activity.}, journal = {Biofouling}, volume = {33}, number = {1}, pages = {1-13}, doi = {10.1080/08927014.2016.1253684}, pmid = {27882771}, issn = {1029-2454}, mesh = {Acinetobacter baumannii/genetics/*physiology ; Biofilms/*growth & development ; Chromatography, Thin Layer ; Chromobacterium/genetics/physiology ; *Chromosomes, Artificial, Bacterial ; Metagenomics/*methods ; Pseudomonas aeruginosa/genetics/*physiology ; *Quorum Sensing/drug effects/genetics ; }, abstract = {Quorum sensing (QS), a cell-to-cell communication process, entails the production of signaling molecules that enable synchronized gene expression in microbial communities to regulate myriad microbial functions, including biofilm formation. QS disruption may constitute an innovative approach to the design of novel antifouling and anti-biofilm agents. To identify novel quorum sensing inhibitors (QSI), 2,500 environmental bacterial artificial chromosomes (BAC) from uncultured marine planktonic bacteria were screened for QSI activity using soft agar overlaid with wild type Chromobacterium violaceum as an indicator. Of the BAC library clones, 7% showed high QSI activity (>40%) against the indicator bacterium, suggesting that QSI is common in the marine environment. The most active compound, eluted from BAC clone 14-A5, disrupted QS signaling pathways and reduced biofilm formation in both Pseudomonas aeruginosa and Acinetobacter baumannii. The mass spectra of the active BAC clone (14-A5) that had been visualized by thin layer chromatography was dominated by a m/z peak of 362.1.}, } @article {pmid27881736, year = {2016}, author = {Chua, SL and Ding, Y and Liu, Y and Cai, Z and Zhou, J and Swarup, S and Drautz-Moses, DI and Schuster, SC and Kjelleberg, S and Givskov, M and Yang, L}, title = {Reactive oxygen species drive evolution of pro-biofilm variants in pathogens by modulating cyclic-di-GMP levels.}, journal = {Open biology}, volume = {6}, number = {11}, pages = {}, pmid = {27881736}, issn = {2046-2441}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects ; Biological Evolution ; Cyclic GMP/*analogs & derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Glutathione/pharmacology ; Hydrogen Peroxide/*pharmacology ; Pseudomonas aeruginosa/*drug effects/genetics/metabolism ; Reactive Oxygen Species/*metabolism ; }, abstract = {The host immune system offers a hostile environment with antimicrobials and reactive oxygen species (ROS) that are detrimental to bacterial pathogens, forcing them to adapt and evolve for survival. However, the contribution of oxidative stress to pathogen evolution remains elusive. Using an experimental evolution strategy, we show that exposure of the opportunistic pathogen Pseudomonas aeruginosa to sub-lethal hydrogen peroxide (H2O2) levels over 120 generations led to the emergence of pro-biofilm rough small colony variants (RSCVs), which could be abrogated by l-glutathione antioxidants. Comparative genomic analysis of the RSCVs revealed that mutations in the wspF gene, which encodes for a repressor of WspR diguanylate cyclase (DGC), were responsible for increased intracellular cyclic-di-GMP content and production of Psl exopolysaccharide. Psl provides the first line of defence against ROS and macrophages, ensuring the survival fitness of RSCVs over wild-type P. aeruginosa Our study demonstrated that ROS is an essential driving force for the selection of pro-biofilm forming pathogenic variants. Understanding the fundamental mechanism of these genotypic and phenotypic adaptations will improve treatment strategies for combating chronic infections.}, } @article {pmid27881324, year = {2017}, author = {Derchi, G and Vano, M and Barone, A and Covani, U and Diaspro, A and Salerno, M}, title = {Bacterial adhesion on direct and indirect dental restorative composite resins: An in vitro study on a natural biofilm.}, journal = {The Journal of prosthetic dentistry}, volume = {117}, number = {5}, pages = {669-676}, doi = {10.1016/j.prosdent.2016.08.022}, pmid = {27881324}, issn = {1097-6841}, mesh = {Adonis ; *Bacterial Adhesion ; *Biofilms ; Composite Resins/*chemistry ; Dental Materials/*chemistry ; Dental Restoration, Permanent/*methods ; In Vitro Techniques ; Materials Testing ; Methacrylates ; Polyurethanes ; Surface Properties ; }, abstract = {STATEMENT OF PROBLEM: Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear.

PURPOSE: The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly.

MATERIAL AND METHODS: Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05).

RESULTS: Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (P<.001). No significant differences were observed within the direct composite resins (P>.05). However, within the indirect composite resins a significantly lower level was found for Gradia than Estenia or Signum (P<.01). A partial correlation was observed between composite resin roughness and bacterial adhesion when the second and particularly the third-order statistical moments of the composite resin height distributions were considered.

CONCLUSIONS: Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins. A correlation of bacterial adhesion to surface morphology exists that is described by kurtosis; thus, advanced data analysis is required to discover possible insights into the biologic effects of morphology.}, } @article {pmid27879061, year = {2017}, author = {Bruchmann, J and Pini, I and Gill, TS and Schwartz, T and Levkin, PA}, title = {Patterned SLIPS for the Formation of Arrays of Biofilm Microclusters with Defined Geometries.}, journal = {Advanced healthcare materials}, volume = {6}, number = {1}, pages = {}, doi = {10.1002/adhm.201601082}, pmid = {27879061}, issn = {2192-2659}, mesh = {Biofilms/*growth & development ; Microarray Analysis/*methods ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Biofilms represent an immense problem in medicine due to their strong drug-resistant properties and inherent stress-response activities. Due to the inhomogeneous and very complex architectures of large biofilm aggregates, biofilm studies often suffer from low reproducibility. In this study, an approach to form arrays of homogeneous biofilm microclusters with defined 2D geometries is presented. The method is based on the formation of water-infused hydrophilic porous polymer areas with precise geometries separated by "slippery" lubricant-infused porous surface (SLIPS). Due to the SLIPS' biofilm repellent properties, multiple identical 3D biofilm clusters are formed in the hydrophilic patches that can be used for biofilm screening. Formation of biofilm microcluster arrays of different bacterial strains of Pseudomonas aeruginosa on the SLIPS micropatterns is investigated. Critical parameters influencing minimal adhesive regions for biofilm attachment and minimal SLIPS dimensions to avoid biofilm adhesion are studied. The ability to produce arrays of biofilm microclusters with highly uniform, well-defined shapes opens an opportunity to study interactions of biofilms with various medically relevant factors with a better reproducibility and to investigate the complex biofilm architecture, heterogeneity, and interactions between biofilm subpopulations.}, } @article {pmid27878947, year = {2017}, author = {Tan, CH and Lee, KW and Burmølle, M and Kjelleberg, S and Rice, SA}, title = {All together now: experimental multispecies biofilm model systems.}, journal = {Environmental microbiology}, volume = {19}, number = {1}, pages = {42-53}, doi = {10.1111/1462-2920.13594}, pmid = {27878947}, issn = {1462-2920}, mesh = {Bacteria/*growth & development/*metabolism ; Biofilms/*growth & development ; Biomass ; Microbial Consortia/*physiology ; Microbial Interactions/*physiology ; }, abstract = {Studies of microorganisms have traditionally focused on single species populations, which have greatly facilitated our understanding of the genetics and physiology that underpin microbial growth, adaptation and biofilm development. However, given that most microorganisms exist as multispecies consortia, the field is increasingly exploring microbial communities using a range of technologies traditionally limited to populations, including meta-omics based approaches and high resolution imaging. The experimental communities currently being explored range from relatively low diversity, for example, two to four species, to significantly more complex systems, comprised of several hundred species. Results from both defined and undefined communities have revealed a number of emergent properties, including improved stress tolerance, increased biomass production, community level signalling and metabolic cooperation. Based on results published to date, we submit that community-based studies are timely and increasingly reveal new properties associated with multispecies consortia that could not be predicted by studies of the individual component species. Here, we review a range of defined and undefined experimental systems used to study microbial community interactions.}, } @article {pmid27878401, year = {2017}, author = {Al-Seraih, A and Belguesmia, Y and Baah, J and Szunerits, S and Boukherroub, R and Drider, D}, title = {Enterocin B3A-B3B produced by LAB collected from infant faeces: potential utilization in the food industry for Listeria monocytogenes biofilm management.}, journal = {Antonie van Leeuwenhoek}, volume = {110}, number = {2}, pages = {205-219}, doi = {10.1007/s10482-016-0791-5}, pmid = {27878401}, issn = {1572-9699}, mesh = {Anti-Bacterial Agents/isolation & purification/pharmacology ; Biofilms/*drug effects ; Bridged-Ring Compounds/isolation & purification/pharmacology ; Enterococcus faecalis/metabolism ; Feces/*microbiology ; *Food Microbiology ; Humans ; Listeria monocytogenes/*drug effects ; Microbial Sensitivity Tests ; Nisin/pharmacology ; }, abstract = {Enterococcus faecalis B3A-B3B produces the bacteriocin B3A-B3B with activity against Listeria monocytogenes, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium perfringens, but apparently not against fungi or Gram-negative bacteria, except for Salmonella Newport. B3A-B3B enterocin has two different nucleotides but similar amino acid composition to the class IIb MR10A-MR10B enterocin. B3A-B3B consists of two peptides of predicted molecular mass of 5176.31 Da (B3A) and 5182.21 Da (B3B). Importantly, B3A-B3B impeded biofilm formation of the foodborne pathogen L. monocytogenes 162 grown on stainless steel. The antimicrobial treatment of stainless steel with nisin (1 or 16 mg ml[-1]) decreased the cell numbers by about 2 log CFU ml[-1], thereby impeding the biofilm formation by L. monocytogenes 162 or its nisin-resistant derivative strain L. monocytogenes 162R. Furthermore, the combination of nisin and B3A-B3B enterocin reduced the MIC required to inhibit this pathogen grown in planktonic or biofilm cultures.}, } @article {pmid27878114, year = {2016}, author = {Isakozawa, Y and Migita, H and Takesawa, S}, title = {Efficacy of Biofilm Removal From Hemodialysis Piping.}, journal = {Nephro-urology monthly}, volume = {8}, number = {5}, pages = {e39332}, pmid = {27878114}, issn = {2251-7006}, abstract = {BACKGROUND: Central dialysate fluid delivery systems (CDDS) are used by dialysis centers in Japan, and although these systems are effective at delivering dialysate, they have a complex piping network with numerous sites where contamination can develop. In Japan, cleaning disinfectants have been clinically evaluated based on endotoxin levels and bacterial counts, but there have been no published studies evaluating the biofilm removal efficacy of these agents at the electron microscope level.

OBJECTIVES: In this study, we used electron microscopy to evaluate the effectiveness of various cleaning disinfectants in removing biofilms from hemodialysis piping.

METHODS: Liquid nitrogen was used to sever a section of dialysis piping on which a biofilm had formed during clinical use. Sodium hypochlorite, acetic acid, and peracetic acid were used at stock-solution concentrations as cleaning disinfectants. These disinfectants were tested at room temperature and when heated (80°C). After cleaning and disinfection, biofilm removal from the surface of the piping was evaluated using a scanning electron microscope (SEM).

RESULTS: Sodium hypochlorite did not show good biofilm removal at room temperature or when heated. Acetic acid was more effective at biofilm removal when heated than at room temperature. Peracetic acid was highly effective at biofilm removal at both room temperature and when heated.

CONCLUSIONS: Cleaning and disinfection using a disinfectant at a high temperature and high concentration effectively removes biofilms from hemodialysis piping. However, long-term exposure to disinfectants may affect the piping material.}, } @article {pmid27874198, year = {2017}, author = {Ali, SG and Ansari, MA and Khan, HM and Jalal, M and Mahdi, AA and Cameotra, SS}, title = {Crataeva nurvala nanoparticles inhibit virulence factors and biofilm formation in clinical isolates of Pseudomonas aeruginosa.}, journal = {Journal of basic microbiology}, volume = {57}, number = {3}, pages = {193-203}, doi = {10.1002/jobm.201600175}, pmid = {27874198}, issn = {1521-4028}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Capparaceae/*chemistry ; Drug Resistance, Multiple, Bacterial ; Hemolysin Proteins/antagonists & inhibitors/biosynthesis/drug effects ; Metal Nanoparticles/*chemistry/ultrastructure ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; Pentacyclic Triterpenes/pharmacology ; Plant Extracts/*pharmacology ; Plants, Medicinal/chemistry ; Proteolysis/drug effects ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology/ultrastructure ; Pyocyanine/biosynthesis ; Quorum Sensing/drug effects ; Silver ; Virulence Factors/*antagonists & inhibitors ; }, abstract = {Green synthesized nanoparticles have gained great attention due to their non-toxic and non-hazardous nature. In the present study, bark extract of the medicinal plant in Ayurveda Crataeva nurvala (Buch-Ham) (CN) was chosen for the biosynthesis of silver nanoparticles (AgNPs). These NPs were characterized by Ultra violet visible spectroscopy, Fourier Transform Infra Red, Atomic Force Microscopy, and Transmission Electron Microscopy (TEM). The average particle size of green synthesized CN-AgNPs was 15.2 ± 1.01 nm. Gas chromatography- mass spectrometry analysis of methanolic bark extract involved in the formation of CN-AgNPs revealed lupeol as a major active component. In this study, CN-AgNPs (15 μg ml[-1]) efficiently suppressed the production of quorum sensing mediated virulence factors viz. pyocyanin, protease, hemolysin, and biofilm formation in Pseudomonas aeruginosa. The pyocyanin production was strongly inhibited (74.64%) followed by proteolysis (47.3%) and hemolysin production (47.7%). However, the biofilm forming ability was maximally reduced up to 79.70%. Moreover, the Confocal Laser Scanning Microscopic Analysis showed that CN-AgNPs inhibit colonization of P. aeruginosa on to the surface. Furthermore, TEM analysis revealed internalization of CN-AgNPs inside the bacterial cell. It is concluded that green synthesized AgNPs have great potential to inhibit virulence factors and biofilm forming ability of drug-resistant clinical isolates of P. aeruginosa.}, } @article {pmid27872845, year = {2016}, author = {Ramasamy, M and Lee, J}, title = {Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {1851242}, pmid = {27872845}, issn = {2314-6141}, mesh = {Animals ; Anti-Infective Agents/administration & dosage ; Biocompatible Materials/*administration & dosage ; Biofilms/*growth & development ; Community-Acquired Infections/*prevention & control ; Equipment and Supplies/*microbiology ; Health Personnel ; Humans ; Infection Control/*methods ; Nanotechnology/*methods ; Surface Properties ; }, abstract = {Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces.}, } @article {pmid27872813, year = {2016}, author = {Dees, MW and Brurberg, MB and Lysøe, E}, title = {Complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from lettuce (Lactuca sativa) originating from a conventional field in Norway.}, journal = {Genomics data}, volume = {10}, number = {}, pages = {135-136}, pmid = {27872813}, issn = {2213-5960}, abstract = {Here, we present the 3,795,952 bp complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from conventionally grown lettuce (Lactuca sativa) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017580.}, } @article {pmid27872164, year = {2017}, author = {Shelton, CL and Conrady, DG and Herr, AB}, title = {Functional consequences of B-repeat sequence variation in the staphylococcal biofilm protein Aap: deciphering the assembly code.}, journal = {The Biochemical journal}, volume = {474}, number = {3}, pages = {427-443}, pmid = {27872164}, issn = {1470-8728}, support = {R01 GM094363/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Bacterial Adhesion/*physiology ; Bacterial Proteins/*chemistry/genetics/metabolism ; Binding Sites ; Biofilms/*growth & development ; Cloning, Molecular ; Crystallography, X-Ray ; Escherichia coli/genetics/metabolism ; Gene Expression ; *Genetic Variation ; Kinetics ; Models, Molecular ; Protein Binding ; Protein Denaturation ; Protein Folding ; Protein Interaction Domains and Motifs ; Protein Multimerization ; Protein Stability ; Protein Structure, Secondary ; Recombinant Proteins/chemistry/genetics/metabolism ; Sequence Alignment ; Staphylococcus epidermidis/*physiology ; Static Electricity ; Zinc/*chemistry/metabolism ; }, abstract = {Staphylococcus epidermidis is an opportunistic pathogen that can form robust biofilms that render the bacteria resistant to antibiotic action and immune responses. Intercellular adhesion in S. epidermidis biofilms is mediated by the cell wall-associated accumulation-associated protein (Aap), via zinc-mediated self-assembly of its B-repeat region. This region contains up to 17 nearly identical sequence repeats, with each repeat assumed to be functionally equivalent. However, Aap B-repeats exist as two subtypes, defined by a cluster of consensus or variant amino acids. These variable residues are positioned near the zinc-binding (and dimerization) site and the stability determinant for the B-repeat fold. We have characterized four B-repeat constructs to assess the functional relevance of the two Aap B-repeat subtypes. Analytical ultracentrifugation experiments demonstrated that constructs with the variant sequence show reduced or absent Zn[2+]-induced dimerization. Likewise, circular dichroism thermal denaturation experiments showed that the variant sequence could significantly stabilize the fold, depending on its location within the construct. Crystal structures of three of the constructs revealed that the side chains from the variant sequence form an extensive bonding network that can stabilize the fold. Furthermore, altered distribution of charged residues between consensus and variant sequences changes the electrostatic potential in the vicinity of the Zn[2+]-binding site, providing a mechanistic explanation for the loss of zinc-induced dimerization in the variant constructs. These data suggest an assembly code that defines preferred oligomerization modes of the B-repeat region of Aap and a slip-grip model for initial contact followed by firm intercellular adhesion during biofilm formation.}, } @article {pmid27871756, year = {2017}, author = {Miao, L and Wang, C and Hou, J and Wang, P and Ao, Y and Li, Y and Yao, Y and Lv, B and Yang, Y and You, G and Xu, Y and Gu, Q}, title = {Response of wastewater biofilm to CuO nanoparticle exposure in terms of extracellular polymeric substances and microbial community structure.}, journal = {The Science of the total environment}, volume = {579}, number = {}, pages = {588-597}, doi = {10.1016/j.scitotenv.2016.11.056}, pmid = {27871756}, issn = {1879-1026}, mesh = {Biofilms/*drug effects ; Copper/*toxicity ; Nanoparticles/*toxicity ; *Waste Disposal, Fluid ; Wastewater/chemistry/*microbiology ; *Water Microbiology ; }, abstract = {The growing production and application of CuO nanoparticles increase the chance that these particles will be released into wastewater treatment plants (WWTPs) and interact with microorganisms. However, the toxicity response mechanism of biofilm to NP exposure may be different from that of activated sludge due to the denser and stronger microbial aggregate structure of biofilm. Thus, in this study, the response to CuO NPs of wastewater biofilm collected from a rotating biological contactor was investigated. Short-term exposure (24h) to CuO NPs led to a great loss in cell viability, and SEM-EDS images revealed that the nano-CuO aggregates were not transformed to Cu-S species in the biofilm samples. In response, more extracellular polymeric substance (EPS) (especially loosely bound-EPS) was produced in wastewater biofilm exposed to CuO NPs, with a higher content of protein compared to polysaccharides. The shifts of fluorescence intensity and peak locations in 3D-EEM fluorescence spectra indicated chemical changes of the EPS components. FT-IR analysis revealed that exposure to nano-CuO had more distinct effects on the functional groups of proteins and polysaccharides in LB-EPS. Illumina sequencing of 16S rRNA gene amplicons revealed that CuO NPs enhanced bacterial diversity. The bacterial community structure significantly shifted, with a significantly increased abundance of Comamonas, a slight increase in Zoogloea, and a notable decrease in Flavobacterium. The shifts of these dominant genera may be associated with altered EPS production, which might result in microbial community function fluctuations. In conclusion, exposure to high concentrations of CuO NPs has the potential to shape wastewater biofilm bacterial community structure.}, } @article {pmid27871747, year = {2017}, author = {Torresi, E and Escolà Casas, M and Polesel, F and Plósz, BG and Christensson, M and Bester, K}, title = {Impact of external carbon dose on the removal of micropollutants using methanol and ethanol in post-denitrifying Moving Bed Biofilm Reactors.}, journal = {Water research}, volume = {108}, number = {}, pages = {95-105}, doi = {10.1016/j.watres.2016.10.068}, pmid = {27871747}, issn = {1879-2448}, mesh = {*Biofilms ; Bioreactors ; Carbon/*metabolism ; Ethanol ; Methanol ; RNA, Ribosomal, 16S ; Waste Disposal, Fluid ; }, abstract = {Addition of external carbon sources to post-denitrification systems is frequently used in wastewater treatment plants to enhance nitrate removal. However, little is known about the fate of micropollutants in post-denitrification systems and the influence of external carbon dosing on their removal. In this study, we assessed the effects of two different types and availability of commonly used carbon sources -methanol and ethanol- on the removal of micropollutants in biofilm systems. Two laboratory-scale moving bed biofilm reactors (MBBRs), containing AnoxKaldnes K1 carriers with acclimated biofilm from full-scale systems, were operated in continuous-flow using wastewater dosed with methanol and ethanol, respectively. Batch experiments with 22 spiked pharmaceuticals were performed to assess removal kinetics. Acetyl-sulfadiazine, atenolol, citalopram, propranolol and trimethoprim were easily biotransformed in both MBBRs (biotransformations rate constants kbio between 1.2 and 12.9 L gbiomass[-1] d[-1]), 13 compounds were moderately biotransformed (rate constants between 0.2 and 2 L gbiomass[-1] d[-1]) and 4 compounds were recalcitrant. The methanol-dosed MBBR showed higher kbio (e.g., 1.5-2.5-fold) than in the ethanol-dosed MBBR for 9 out of the 22 studied compounds, equal kbio for 10 compounds, while 3 compounds (i.e., targeted sulfonamides) were biotransformed faster in the ethanol-dosed MBBR. While biotransformation of most of the targeted compounds followed first-order kinetics, removal of venlafaxine, carbamazepine, sulfamethoxazole and sulfamethizole could be described with a cometabolic model. Analyses of the microbial composition in the biofilms using 16S rRNA amplicon sequencing revealed that the methanol-dosed MBBR contained higher microbial richness than the one dosed with ethanol, suggesting that improved biotransformation of targeted compounds could be associated with higher microbial richness. During continuous-flow operation, at conditions representative of full-scale denitrification systems (hydraulic residence time = 2 h), the removal efficiencies of micropollutants were below 35% in both MBBRs, with the exception of atenolol and trimethoprim (>80%). Overall, this study demonstrated that MBBRs used for post-denitrification could be optimized to enhance the biotransformation of a number of micropollutants by accounting for optimal carbon sources and extended residence time.}, } @article {pmid27870886, year = {2016}, author = {Wong, EH and Ng, CG and Chua, EG and Tay, AC and Peters, F and Marshall, BJ and Ho, B and Goh, KL and Vadivelu, J and Loke, MF}, title = {Comparative Genomics Revealed Multiple Helicobacter pylori Genes Associated with Biofilm Formation In Vitro.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0166835}, pmid = {27870886}, issn = {1932-6203}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Genome, Bacterial ; Genomics/*methods ; Helicobacter pylori/classification/genetics/*physiology ; High-Throughput Nucleotide Sequencing ; In Vitro Techniques ; Sequence Analysis, DNA ; }, abstract = {BACKGROUND: Biofilm formation by Helicobacter pylori may be one of the factors influencing eradication outcome. However, genetic differences between good and poor biofilm forming strains have not been studied.

MATERIALS AND METHODS: Biofilm yield of 32 Helicobacter pylori strains (standard strain and 31 clinical strains) were determined by crystal-violet assay and grouped into poor, moderate and good biofilm forming groups. Whole genome sequencing of these 32 clinical strains was performed on the Illumina MiSeq platform. Annotation and comparison of the differences between the genomic sequences were carried out using RAST (Rapid Annotation using Subsystem Technology) and SEED viewer. Genes identified were confirmed using PCR.

RESULTS: Genes identified to be associated with biofilm formation in H. pylori includes alpha (1,3)-fucosyltransferase, flagellar protein, 3 hypothetical proteins, outer membrane protein and a cag pathogenicity island protein. These genes play a role in bacterial motility, lipopolysaccharide (LPS) synthesis, Lewis antigen synthesis, adhesion and/or the type-IV secretion system (T4SS). Deletion of cagA and cagPAI confirmed that CagA and T4SS were involved in H. pylori biofilm formation.

CONCLUSIONS: Results from this study suggest that biofilm formation in H. pylori might be genetically determined and might be influenced by multiple genes. Good, moderate and poor biofilm forming strain might differ during the initiation of biofilm formation.}, } @article {pmid27870871, year = {2016}, author = {Lee, JA and Robbins, N and Xie, JL and Ketela, T and Cowen, LE}, title = {Functional Genomic Analysis of Candida albicans Adherence Reveals a Key Role for the Arp2/3 Complex in Cell Wall Remodelling and Biofilm Formation.}, journal = {PLoS genetics}, volume = {12}, number = {11}, pages = {e1006452}, pmid = {27870871}, issn = {1553-7404}, mesh = {Actin Cytoskeleton/genetics ; Actin-Related Protein 2-3 Complex/drug effects/*genetics ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*genetics/growth & development/pathogenicity ; Candidiasis/drug therapy/genetics/microbiology ; Cell Adhesion/genetics ; Cell Wall/genetics ; Drug Resistance, Fungal/*genetics ; Endocytosis/genetics ; Fungal Proteins/*biosynthesis/genetics ; Gene Expression Regulation, Fungal ; Genome, Fungal ; Genomics ; Humans ; Metabolic Networks and Pathways/genetics ; Stress, Physiological/genetics ; }, abstract = {Fungal biofilms are complex, structured communities that can form on surfaces such as catheters and other indwelling medical devices. Biofilms are of particular concern with Candida albicans, one of the leading opportunistic fungal pathogens of humans. C. albicans biofilms include yeast and filamentous cells that are surrounded by an extracellular matrix, and they are intrinsically resistant to antifungal drugs such that resolving biofilm infections often requires surgery to remove the contaminated device. C. albicans biofilms form through a regulated process of adhesion to surfaces, filamentation, maturation, and ultimately dispersion. To uncover new strategies to block the initial stages of biofilm formation, we utilized a functional genomic approach to identify genes that modulate C. albicans adherence. We screened a library of 1,481 double barcoded doxycycline-repressible conditional gene expression strains covering ~25% of the C. albicans genome. We identified five genes for which transcriptional repression impaired adherence, including: ARC18, PMT1, MNN9, SPT7, and orf19.831. The most severe adherence defect was observed upon transcriptional repression of ARC18, which encodes a member of the Arp2/3 complex that is involved in regulation of the actin cytoskeleton and endocytosis. Depletion of components of the Arp2/3 complex not only impaired adherence, but also caused reduced biofilm formation, increased cell surface hydrophobicity, and increased exposure of cell wall chitin and β-glucans. Reduced function of the Arp2/3 complex led to impaired cell wall integrity and activation of Rho1-mediated cell wall stress responses, thereby causing cell wall remodelling and reduced adherence. Thus, we identify important functional relationships between cell wall stress responses and a novel mechanism that controls adherence and biofilm formation, thereby illuminating novel strategies to cripple a leading fungal pathogen of humans.}, } @article {pmid27870863, year = {2016}, author = {Melloul, E and Luiggi, S and Anaïs, L and Arné, P and Costa, JM and Fihman, V and Briard, B and Dannaoui, E and Guillot, J and Decousser, JW and Beauvais, A and Botterel, F}, title = {Characteristics of Aspergillus fumigatus in Association with Stenotrophomonas maltophilia in an In Vitro Model of Mixed Biofilm.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0166325}, pmid = {27870863}, issn = {1932-6203}, mesh = {Antibiosis ; Aspergillus fumigatus/genetics/*physiology ; Biofilms/*growth & development ; DNA, Bacterial/*genetics ; DNA, Fungal/*genetics ; In Vitro Techniques ; Microbial Viability ; Microscopy, Electron, Scanning ; Microscopy, Electron, Scanning Transmission ; Models, Biological ; Real-Time Polymerase Chain Reaction ; Stenotrophomonas maltophilia/genetics/*physiology ; }, abstract = {BACKGROUND: Biofilms are communal structures of microorganisms that have long been associated with a variety of persistent infections poorly responding to conventional antibiotic or antifungal therapy. Aspergillus fumigatus fungus and Stenotrophomonas maltophilia bacteria are examples of the microorganisms that can coexist to form a biofilm especially in the respiratory tract of immunocompromised patients or cystic fibrosis patients. The aim of the present study was to develop and assess an in vitro model of a mixed biofilm associating S. maltophilia and A. fumigatus by using analytical and quantitative approaches.

MATERIALS AND METHODS: An A. fumigatus strain (ATCC 13073) expressing a Green Fluorescent Protein (GFP) and an S. maltophilia strain (ATCC 13637) were used. Fungal and bacterial inocula (105 conidia/mL and 106 cells/mL, respectively) were simultaneously deposited to initiate the development of an in vitro mixed biofilm on polystyrene supports at 37°C for 24 h. The structure of the biofilm was analysed via qualitative microscopic techniques like scanning electron and transmission electron microscopy, and fluorescence microscopy, and by quantitative techniques including qPCR and crystal violet staining.

RESULTS: Analytic methods revealed typical structures of biofilm with production of an extracellular matrix (ECM) enclosing fungal hyphae and bacteria. Quantitative methods showed a decrease of A. fumigatus growth and ECM production in the mixed biofilm with antibiosis effect of the bacteria on the fungi seen as abortive hyphae, limited hyphal growth, fewer conidia, and thicker fungal cell walls.

CONCLUSION: For the first time, a mixed A. fumigatus-S. maltophilia biofilm was validated by various analytical and quantitative approaches and the bacterial antibiosis effect on the fungus was demonstrated. The mixed biofilm model is an interesting experimentation field to evaluate efficiency of antimicrobial agents and to analyse the interactions between the biofilm and the airways epithelium.}, } @article {pmid27870324, year = {2016}, author = {Dhar, BR and Ryu, H and Ren, H and Domingo, JW and Chae, J and Lee, HS}, title = {High Biofilm Conductivity Maintained Despite Anode Potential Changes in a Geobacter-Enriched Biofilm.}, journal = {ChemSusChem}, volume = {9}, number = {24}, pages = {3485-3491}, pmid = {27870324}, issn = {1864-564X}, support = {EPA999999/ImEPA/Intramural EPA/United States ; }, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Electric Conductivity ; Electrodes ; Electron Transport ; Extracellular Space/metabolism ; Geobacter/*metabolism/physiology ; Kinetics ; }, abstract = {This study systematically assessed intracellular electron transfer (IET) and extracellular electron transfer (EET) kinetics with respect to anode potential (Eanode) in a mixed-culture biofilm anode enriched with Geobacter spp. High biofilm conductivity (0.96-1.24 mS cm[-1]) was maintained during Eanode changes from -0.2 to +0.2 V versus the standard hydrogen electrode (SHE), although the steady-state current density significantly decreased from 2.05 to 0.35 A m[-2] in a microbial electrochemical cell. Substantial increase of the Treponema population was observed in the biofilm anode at Eanode =+0.2 V, which reduced intracellular electron-transfer kinetics associated with the maximum specific substrate-utilization rate by a factor of ten. This result suggests that fast EET kinetics can be maintained under dynamic Eanode conditions in a highly conductive biofilm anode as a result of shift of main EET players in the biofilm anode, although Eanode changes can influence IET kinetics.}, } @article {pmid27869180, year = {2016}, author = {Yang, JL and Li, YF and Liang, X and Guo, XP and Ding, DW and Zhang, D and Zhou, S and Bao, WY and Bellou, N and Dobretsov, S}, title = {Silver Nanoparticles Impact Biofilm Communities and Mussel Settlement.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {37406}, pmid = {27869180}, issn = {2045-2322}, mesh = {Animals ; Biofilms/*drug effects ; Biological Assay ; Biomass ; Diatoms/drug effects ; Dimethylpolysiloxanes/pharmacology ; Metal Nanoparticles/*chemistry ; Mytilus/*drug effects ; Phylogeny ; Principal Component Analysis ; Silver/*pharmacology ; }, abstract = {Silver nanoparticles (AgNPs) demonstrating good antimicrobial activity are widely used in many fields. However, the impact of AgNPs on the community structures of marine biofilms that drive biogeochemical cycling processes and the recruitment of marine invertebrate larvae remains unknown. Here, we employed MiSeq sequencing technology to evaluate the bacterial communities of 28-day-old marine biofilms formed on glass, polydimethylsiloxane (PDMS), and PDMS filled with AgNPs and subsequently tested the influence of these marine biofilms on plantigrade settlement by the mussel Mytilus coruscus. AgNP-filled PDMS significantly reduced the dry weight and bacterial density of biofilms compared with the glass and PDMS controls. AgNP incorporation impacted bacterial communities by reducing the relative abundance of Flavobacteriaceae (phylum: Bacteroidetes) and increasing the relative abundance of Vibrionaceae (phylum: Proteobacteria) in 28-day-old biofilms compared to PDMS. The settlement rate of M. coruscus on 28-day-old biofilms developed on AgNPs was lower by >30% compared to settlement on control biofilms. Thus, the incorporation of AgNPs influences biofilm bacterial communities in the marine environment and subsequently inhibits mussel settlement.}, } @article {pmid27869109, year = {2016}, author = {Jeffet, U and Nasrallah, R and Sterer, N}, title = {Effect of red dyes on blue light phototoxicity against VSC producing bacteria in an experimental oral biofilm.}, journal = {Journal of breath research}, volume = {10}, number = {4}, pages = {046011}, doi = {10.1088/1752-7155/10/4/046011}, pmid = {27869109}, issn = {1752-7163}, mesh = {Bacteria/*growth & development ; Biofilms/*drug effects ; Breath Tests ; Coloring Agents/*metabolism ; Dermatitis, Phototoxic/*metabolism ; Halitosis/*microbiology ; Humans ; *Light ; Photosensitizing Agents ; Sulfides/*metabolism ; }, abstract = {Oral malodour is considered to be caused mainly by the production of volatile sulfide compounds (VSC) by anaerobic Gram-negative oral bacteria. Previous study showed that these bacteria were susceptible to blue light (wavelengths of 400-500 nm). In the present study, we tested the effect of blue light in the presence of red dyes on malodour production in an experimental oral biofilm. Biofilms were exposed to a plasma-arc light source for 30, 60, and 120 s (i.e. fluences of 41, 82, and 164 J cm[-2], respectively) with the addition of erythrosine, natural red and rose bengal (0.01, 0.1 and 1% w/v). Following light exposure biofilm samples were examined for malodour production (Odour judge), VSC production (Halimeter[™]), VSC producing bacteria quantification using microscopy sulfide assay (MSA) and reactive oxygen species (ROS) production. Results showed that the exposure of experimental oral biofilm to blue light in the presence of rose bengal caused an increased reduction in VSC and malodour production concomitant with an increase in ROS production. These results suggest that rose bengal might be effective as a blue light photosensitizer against VSC producing bacteria.}, } @article {pmid27868469, year = {2017}, author = {Azeredo, J and Azevedo, NF and Briandet, R and Cerca, N and Coenye, T and Costa, AR and Desvaux, M and Di Bonaventura, G and Hébraud, M and Jaglic, Z and Kačániová, M and Knøchel, S and Lourenço, A and Mergulhão, F and Meyer, RL and Nychas, G and Simões, M and Tresse, O and Sternberg, C}, title = {Critical review on biofilm methods.}, journal = {Critical reviews in microbiology}, volume = {43}, number = {3}, pages = {313-351}, doi = {10.1080/1040841X.2016.1208146}, pmid = {27868469}, issn = {1549-7828}, mesh = {Bacterial Adhesion ; *Biofilms/growth & development ; Databases, Factual ; Equipment Design ; Image Processing, Computer-Assisted/*methods ; In Situ Hybridization, Fluorescence ; Lab-On-A-Chip Devices ; Microbiological Techniques/*instrumentation/methods ; Microscopy/*methods ; Molecular Biology/*methods ; Software ; }, abstract = {Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.}, } @article {pmid27868063, year = {2016}, author = {Cincarova, L and Polansky, O and Babak, V and Kulich, P and Kralik, P}, title = {Changes in the Expression of Biofilm-Associated Surface Proteins in Staphylococcus aureus Food-Environmental Isolates Subjected to Sublethal Concentrations of Disinfectants.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {4034517}, pmid = {27868063}, issn = {2314-6141}, mesh = {Bacterial Proteins/metabolism ; Biofilms/*drug effects/growth & development ; Cell Survival/drug effects ; Disinfectants/*administration & dosage ; Dose-Response Relationship, Drug ; *Food Microbiology ; Gene Expression Regulation, Bacterial/drug effects/physiology ; Membrane Proteins/*metabolism ; Species Specificity ; Staphylococcus aureus/classification/*drug effects/*metabolism ; }, abstract = {Sublethal concentrations (sub-MICs) of certain disinfectants are no longer effective in removing biofilms from abiotic surfaces and can even promote the formation of biofilms. Bacterial cells can probably adapt to these low concentrations of disinfectants and defend themselves by way of biofilm formation. In this paper, we report on three Staphylococcus aureus biofilm formers (strong B+++, moderate B++, and weak B+) that were cultivated with sub-MICs of commonly used disinfectants, ethanol or chloramine T, and quantified using Syto9 green fluorogenic nucleic acid stain. We demonstrate that 1.25-2.5% ethanol and 2500 μg/mL chloramine T significantly enhanced S. aureus biofilm formation. To visualize differences in biofilm compactness between S. aureus biofilms in control medium, 1.25% ethanol, or 2500 μg/mL chloramine T, scanning electron microscopy was used. To describe changes in abundance of surface-exposed proteins in ethanol- or chloramine T-treated biofilms, surface proteins were prepared using a novel trypsin shaving approach and quantified after dimethyl labeling by LC-LTQ/Orbitrap MS. Our data show that some proteins with adhesive functions and others with cell maintenance functions and virulence factor EsxA were significantly upregulated by both treatments. In contrast, immunoglobulin-binding protein A was significantly downregulated for both disinfectants. Significant differences were observed in the effect of the two disinfectants on the expression of surface proteins including some adhesins, foldase protein PrsA, and two virulence factors.}, } @article {pmid27867752, year = {2016}, author = {Wilkinson, HN and McBain, AJ and Stephenson, C and Hardman, MJ}, title = {Comparing the Effectiveness of Polymer Debriding Devices Using a Porcine Wound Biofilm Model.}, journal = {Advances in wound care}, volume = {5}, number = {11}, pages = {475-485}, pmid = {27867752}, issn = {2162-1918}, abstract = {Objective: Debridement to remove necrotic and/or infected tissue and promote active healing remains a cornerstone of contemporary chronic wound management. While there has been a recent shift toward less invasive polymer-based debriding devices, their efficacy requires rigorous evaluation. Approach: This study was designed to directly compare monofilament debriding devices to traditional gauze using a wounded porcine skin biofilm model with standardized application parameters. Biofilm removal was determined using a surface viability assay, bacterial counts, histological assessment, and scanning electron microscopy (SEM). Results: Quantitative analysis revealed that monofilament debriding devices outperformed the standard gauze, resulting in up to 100-fold greater reduction in bacterial counts. Interestingly, histological and morphological analyses suggested that debridement not only removed bacteria, but also differentially disrupted the bacterially-derived extracellular polymeric substance. Finally, SEM of post-debridement monofilaments showed structural changes in attached bacteria, implying a negative impact on viability. Innovation: This is the first study to combine controlled and defined debridement application with a biologically relevant ex vivo biofilm model to directly compare monofilament debriding devices. Conclusion: These data support the use of monofilament debriding devices for the removal of established wound biofilms and suggest variable efficacy towards biofilms composed of different species of bacteria.}, } @article {pmid27867375, year = {2016}, author = {Feng, J and Zhang, S and Shi, W and Zhang, Y}, title = {Ceftriaxone Pulse Dosing Fails to Eradicate Biofilm-Like Microcolony B. burgdorferi Persisters Which Are Sterilized by Daptomycin/ Doxycycline/Cefuroxime without Pulse Dosing.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1744}, pmid = {27867375}, issn = {1664-302X}, abstract = {Although the majority of Lyme disease patients can be cured, at least 10-20% of the patients continue to suffer from persisting symptoms such as fatigue, muscular and joint pain, and neurologic impairment after standard 2-4 week antibiotic treatment. While the causes for this post-treatment Lyme disease symptoms are unclear, one possibility is due to Borrelia burgdorferi persisters that are not effectively killed by current antibiotics such as doxycycline or amoxicillin used to treat Lyme disease. A previous study showed that four rounds of ceftriaxone pulse dosing treatment eradicated B. burgdorferi persisters in vitro using a relatively young late log phase culture (5 day old). In this study, we investigated if ceftriaxone pulse dosing could also eradicate B. burgdorferi persisters in older stationary phase cultures (10 day old) enriched with more resistant microcolony form of persisters. We found that ceftriaxone pulse dosing could only eradicate planktonic log phase B. burgdorferi spirochetal forms and round body forms but not more resistant aggregated biofilm-like microcolony persisters enriched in stationary phase cultures. Moreover, we found that not all drugs are suitable for pulse dosing, with bactericidal drugs ceftriaxone and cefuroxime being more appropriate for pulse dosing than bacteriostatic drug doxycycline and persister drug daptomycin. We also showed that drug combination pulse dosing treatment was more effective than single drug pulse dosing. Importantly, we demonstrate that pulse dosing treatment impaired the activity of the persister drug daptomycin and its drug combination against B. burgdorferi persisters and that the most effective way to kill the more resistant biofilm-like microcolonies is the daptomycin/doxycycline/ceftriaxone triple drug combination without pulse dosing. Our findings indicate pulse dosing may not always work as a general principle but rather depends on the specific drugs used, with cidal drugs being more appropriate for pulse dosing than static or persister drugs, and that drug combination approach with persister drugs is more effective at killing the more resistant microcolony form of persisters than pulse dosing. These observations may have implications for more effective treatment of Lyme disease. Future studies are required to validate these findings in animal models of B. burgdorferi persistence.}, } @article {pmid27865827, year = {2017}, author = {Vinod Kumar, K and Lall, C and Vimal Raj, R and Vedhagiri, K and Kartick, C and Surya, P and Natarajaseenivasan, K and Vijayachari, P}, title = {Overexpression of heat shock GroEL stress protein in leptospiral biofilm.}, journal = {Microbial pathogenesis}, volume = {102}, number = {}, pages = {8-11}, doi = {10.1016/j.micpath.2016.11.010}, pmid = {27865827}, issn = {1096-1208}, mesh = {Bacterial Proteins/chemistry/genetics/metabolism ; Biofilms/*growth & development ; Chaperonin 60/chemistry/*genetics/metabolism ; *Gene Expression ; Immunoblotting ; Leptospira/*genetics/*growth & development/metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {Leptospira is the causative agent of leptospirosis, which is an emerging zoonotic disease. Recent studies on Leptospira have demonstrated biofilm formation on abiotic surfaces. The protein expressed in the biofilm was investigated by using SDS-PAGE and immunoblotting in combination with MALDI-TOF mass spectrometry. The proteins expressed in Leptospira biofilm and planktonic cells was analyzed and compared. Among these proteins, one (60 kDa) was found to overexpress in biofilm as compared to the planktonic cells. MALDI-TOF analysis identified this protein as stress and heat shock chaperone GroEL. Our findings demonstrate that GroEL is associated with Leptospira biofilm. GroEL is conserved, highly immunogenic and a prominent stress response protein in pathogenic Leptospira spp., which may have clinical relevance.}, } @article {pmid27864170, year = {2017}, author = {Algburi, A and Comito, N and Kashtanov, D and Dicks, LMT and Chikindas, ML}, title = {Control of Biofilm Formation: Antibiotics and Beyond.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {3}, pages = {}, pmid = {27864170}, issn = {1098-5336}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Terminology as Topic ; }, abstract = {Biofilm-associated bacteria are less sensitive to antibiotics than free-living (planktonic) cells. Furthermore, with variations in the concentration of antibiotics throughout a biofilm, microbial cells are often exposed to levels below inhibitory concentrations and may develop resistance. This, as well as the irresponsible use of antibiotics, leads to the selection of pathogens that are difficult to eradicate. The Centers for Disease Control and Prevention use the terms "antibiotic" and "antimicrobial agent" interchangeably. However, a clear distinction between these two terms is required for the purpose of this assessment. Therefore, we define "antibiotics" as pharmaceutically formulated and medically administered substances and "antimicrobials" as a broad category of substances which are not regulated as drugs. This comprehensive minireview evaluates the effect of natural antimicrobials on pathogens in biofilms when used instead of, or in combination with, commonly prescribed antibiotics.}, } @article {pmid27863264, year = {2017}, author = {Gallarato, LA and Mulko, LE and Dardanelli, MS and Barbero, CA and Acevedo, DF and Yslas, EI}, title = {Synergistic effect of polyaniline coverage and surface microstructure on the inhibition of Pseudomonas aeruginosa biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {150}, number = {}, pages = {1-7}, doi = {10.1016/j.colsurfb.2016.11.014}, pmid = {27863264}, issn = {1873-4367}, mesh = {Aniline Compounds/*chemistry ; Bacterial Adhesion ; Biocompatible Materials/chemistry ; *Biofilms ; Catheters ; Drug Resistance, Bacterial ; Equipment and Supplies ; Gentian Violet/chemistry ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Polyethylene Terephthalates/chemistry ; Pseudomonas aeruginosa/*physiology ; Surface Properties ; }, abstract = {Biofilm Formation is a survival strategy for microorganisms to adapt to their environment. Microbial cells in biofilm become tolerant and resistant to antibiotics and immune responses, increasing the difficulties for the clinical treatment of microbial infections. The surface chemistry and the micro/nano-topography of solid interfaces play a major role in mediating microorganism activity and adhesion. The effect of the surface chemical composition and topography on the adhesion and viability of Pseudomonas aeruginosa was studied. Polymeric (polyethylene terephthalate) surfaces were covered with a conducting polymer (polyaniline, PANI) film by in-situ polymerization and microstructured by Direct Laser Interference Patterning (DLIP). The viability of Pseudomonas aeruginosa on the different surfaces was investigated. The physicochemical properties of the surfaces were characterized by water contact angle measurements, scanning electron microscopy and atomic force microscopy. Bacterial biofilms were imaged by atomic force and scanning electron microscopies. The bacterial viability decreased on PANI compared with the substrate (polyethylene terephthalate) and it decreased even more upon micro-structuring the PANI films. In addition, the biofilm reduction could be improved using polymers with different chemical composition and/or the same polymer with different topographies. Both methods presented diminish the bacterial attachment and biofilm formation. These findings present a high impact related to materials for biomedical engineer applications regarding medical devices, as prostheses or catheters.}, } @article {pmid27860087, year = {2017}, author = {Lou, Z and Wang, H and Tang, Y and Chen, X}, title = {The effect of burdock leaf fraction on adhesion, biofilm formation, quorum sensing and virulence factors of Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {122}, number = {3}, pages = {615-624}, doi = {10.1111/jam.13348}, pmid = {27860087}, issn = {1365-2672}, mesh = {4-Butyrolactone/analogs & derivatives/antagonists & inhibitors/metabolism ; Arctium/*chemistry ; Biofilms/*drug effects ; Homoserine/analogs & derivatives/antagonists & inhibitors/metabolism ; Pancreatic Elastase/antagonists & inhibitors/metabolism ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Pseudomonas aeruginosa/*drug effects/pathogenicity/physiology ; Pyocyanine/antagonists & inhibitors/metabolism ; Quorum Sensing/*drug effects ; Virulence/*drug effects ; Virulence Factors/chemistry/metabolism ; }, abstract = {AIMS: This study aimed to evaluate the effect of a fraction of burdock (Arctium lappa L.) leaf on the initial adhesion, biofilm formation, quorum sensing and virulence factors of Pseudomonas aeruginosa.

METHODS AND RESULTS: Antibiofilm activity of the burdock leaf fraction was studied by the method of crystal violet staining. When the concentration of the burdock leaf fraction was 2·0 mg ml[-1] , the inhibition rates on biofilm formation of P. aeruginosa were 100%. The burdock leaf fraction was found to inhibit the formation of biofilm by reducing bacterial surface hydrophobicity, decreasing bacterial aggregation ability and inhibiting swarming motility. Interestingly, the burdock leaf fraction inhibited the secretion of quorum-sensing (QS) signalling molecule 3-oxo-C12-HSL and interfered quorum sensing. Moreover, the QS-regulated pyocyanin and elastase were also inhibited. Chemical composition analysis by UPLC-MS showed 11 active compounds in the burdock leaf fraction.

CONCLUSIONS: The burdock leaf fraction significantly inhibited the formation of biofilm and quorum sensing, as well as significantly decreased the content of virulence factors.

This study introduces a natural and effective bacterial biofilm inhibitor, which could also significantly decrease the content of virulence factors and the drug resistance of P. aeruginosa.}, } @article {pmid27859408, year = {2017}, author = {Salzillo, M and Vastano, V and Capri, U and Muscariello, L and Marasco, R}, title = {Pyruvate dehydrogenase subunit β of Lactobacillus plantarum is a collagen adhesin involved in biofilm formation.}, journal = {Journal of basic microbiology}, volume = {57}, number = {4}, pages = {353-357}, doi = {10.1002/jobm.201600575}, pmid = {27859408}, issn = {1521-4028}, mesh = {Adhesins, Bacterial/chemistry/*metabolism ; Bacterial Adhesion ; Biofilms/*growth & development ; Collagen/*metabolism ; Humans ; Lactobacillus plantarum/*enzymology/genetics/metabolism ; Mutation ; Pyruvate Dehydrogenase Complex/*chemistry/genetics/isolation & purification/*metabolism ; }, abstract = {Multi-functional surface proteins have been observed in a variety of pathogenic bacteria, where they mediate host cell adhesion and invasion, as well as in commensal bacterial species, were they mediate positive interaction with the host. Among these proteins, some glycolytic enzymes, expressed on the bacterial cell surface, can bind human extracellular matrix components (ECM). A major target for them is collagen, an abundant glycoprotein of connective tissues. We have previously shown that the enolase EnoA1 of Lactobacillus plantarum, one of the most predominant species in the gut microbiota of healthy individuals, is involved in binding with collagen type I (CnI). In this study, we found that PDHB, a component of the pyruvate dehydrogenase complex, contributes to the L. plantarum LM3 adhesion to CnI. By a cellular adhesion assay to immobilized CnI, we show that LM3-B1 cells, carrying a null mutation in the pdhB gene, bind to CnI - coated surfaces less efficiently than wild-type cells. Moreover, we show that the PDHB-CnI interaction requires a native state for PDHB. We also analyzed the ability to develop biofilm in wild-type and mutant strains and we found that the lack of the PDHB on cell surface generates cells partially impaired in biofilm development.}, } @article {pmid27858472, year = {2017}, author = {Malone, M and Goeres, DM and Gosbell, I and Vickery, K and Jensen, S and Stoodley, P}, title = {Approaches to biofilm-associated infections: the need for standardized and relevant biofilm methods for clinical applications.}, journal = {Expert review of anti-infective therapy}, volume = {15}, number = {2}, pages = {147-156}, doi = {10.1080/14787210.2017.1262257}, pmid = {27858472}, issn = {1744-8336}, mesh = {Anti-Infective Agents/administration & dosage/pharmacology/*therapeutic use ; Biofilms/*drug effects/growth & development ; Biomedical Research/methods/standards ; Chronic Disease ; Communicable Disease Control/*methods/standards ; Communicable Diseases/*drug therapy/epidemiology/immunology/microbiology ; Humans ; Models, Biological ; }, abstract = {The concept of biofilms in human health and disease is now widely accepted as cause of chronic infection. Typically, biofilms show remarkable tolerance to many forms of treatments and the host immune response. This has led to vast increase in research to identify new (and sometimes old) anti-biofilm strategies that demonstrate effectiveness against these tolerant phenotypes. Areas covered: Unfortunately, a standardized methodological approach of biofilm models has not been adopted leading to a large disparity between testing conditions. This has made it almost impossible to compare data across multiple laboratories, leaving large gaps in the evidence. Furthermore, many biofilm models testing anti-biofilm strategies aimed at the medical arena have not considered the matter of relevance to an intended application. This may explain why some in vitro models based on methodological designs that do not consider relevance to an intended application fail when applied in vivo at the clinical level. Expert commentary: This review will explore the issues that need to be considered in developing performance standards for anti-biofilm therapeutics and provide a rationale for the need to standardize models/methods that are clinically relevant. We also provide some rational as to why no standards currently exist.}, } @article {pmid27853712, year = {2016}, author = {Rossi, C and Chaves-López, C and Serio, A and Goffredo, E and Goga, BT and Paparella, A}, title = {Influence of Incubation Conditions on Biofilm Formation by Pseudomonas Fluorescens Isolated from Dairy Products and Dairy Manufacturing Plants.}, journal = {Italian journal of food safety}, volume = {5}, number = {3}, pages = {5793}, pmid = {27853712}, issn = {2239-7132}, abstract = {In this study, biofilm formation of 64 Pseudomonas fluorescens strains isolated from milk, dairy products and dairy plants was compared. The strains were grown on Tryptic Soy Broth supplemented with 0.2% of glucose, on polystyrene microplates at 10 and 30°C for 48 h. In general, 57/64 P. fluorescens strains formed biofilm, although with great variability at both tested temperatures. Moreover, our results evidenced that the biofilm-forming ability of the strains was temperature- and strain-dependent. Interestingly, the ability of several isolates to form biofilms was associated with the low temperature after 48 h. Our findings evidenced that temperature was more important than incubation time for biofilm formation. Considering the origin of the strains, it is relevant to underline the importance of performing accurate cleaning and disinfection procedures on food processing surfaces.}, } @article {pmid27846284, year = {2016}, author = {Davey, L and Halperin, SA and Lee, SF}, title = {Mutation of the Streptococcus gordonii Thiol-Disulfide Oxidoreductase SdbA Leads to Enhanced Biofilm Formation Mediated by the CiaRH Two-Component Signaling System.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0166656}, pmid = {27846284}, issn = {1932-6203}, mesh = {Animals ; Bacterial Proteins/*genetics/metabolism ; Biofilms/growth & development ; Gene Expression Regulation, Bacterial ; Histidine Kinase/*genetics/metabolism ; Humans ; Membrane Proteins/*genetics/metabolism ; Mice ; Mutation ; Operon/genetics ; Phenotype ; Protein Kinases/*genetics/metabolism ; Signal Transduction ; Streptococcal Infections/genetics/*microbiology ; Streptococcus gordonii/*genetics/pathogenicity ; }, abstract = {Streptococcus gordonii is a commensal inhabitant of human oral biofilms. Previously, we identified an enzyme called SdbA that played an important role in biofilm formation by S. gordonii. SdbA is thiol-disulfide oxidoreductase that catalyzes disulfide bonds in secreted proteins. Surprisingly, inactivation of SdbA results in enhanced biofilm formation. In this study we investigated the basis for biofilm formation by the ΔsdbA mutant. The results revealed that biofilm formation was mediated by the interaction between the CiaRH and ComDE two-component signalling systems. Although it did not affect biofilm formation by the S. gordonii parent strain, CiaRH was upregulated in the ΔsdbA mutant and it was essential for the enhanced biofilm phenotype. The biofilm phenotype was reversed by inactivation of CiaRH or by the addition of competence stimulating peptide, the production of which is blocked by CiaRH activity. Competition assays showed that the enhanced biofilm phenotype also corresponded to increased oral colonization in mice. Thus, the interaction between SdbA, CiaRH and ComDE affects biofilm formation both in vitro and in vivo.}, } @article {pmid27845499, year = {2016}, author = {Thummeepak, R and Kongthai, P and Leungtongkam, U and Sitthisak, S}, title = {Distribution of virulence genes involved in biofilm formation in multi-drug resistant Acinetobacter baumannii clinical isolates.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {19}, number = {2}, pages = {121-129}, doi = {10.2436/20.1501.01.270}, pmid = {27845499}, issn = {1139-6709}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*genetics ; Anti-Bacterial Agents ; *Biofilms ; Cross Infection/microbiology ; Humans ; Opportunistic Infections/microbiology ; Thailand ; Virulence/*genetics ; }, abstract = {Acinetobacter baumannii is an opportunistic bacterial pathogen that is the major cause of hospital-acquired infections. It has been shown that A. baumannii with high biofilm formation increases the risk of acquiring infection. In this study, the prevalence of virulence genes involved in biofilm formation was determined in 225 A. baumannii clinical isolates from three hospitals in Thailand. Most of the isolates were multidrug-resistant A. baumannii strains (86.2%). Among all isolates, 76.9% (173/225) showed biofilm formation ability. The association between biofilm forming ability and gentamicin resistance was found. The presence of virulence genes, epsA, bap, ompA, bfmS and blaPER-1 genes, was investigated by PCR. The prevalence of ompA, bfmS, bap, blaPER-1 and epsA genes among the isolated strains was 84.4%, 84%, 48%, 30.2%, respectively. Biofilm formation related genes, ompA and bap were associated with multidrug-resistant A. baumannii strains. The result of this study revealed that a high prevalence of biofilm-forming phenotypes among A. baumannii strains obtained from different hospitals. Effective strategies to prevent infection due to A. baumannii that produce biofilms are therefore needed. [Int Microbiol 19(2):121-129 (2016)].}, } @article {pmid27845497, year = {2016}, author = {Thellin, O and Zorzi, W and Zorzi, D and Delvenne, P and Heinen, E and ElMoualij, B and Quatresooz, P}, title = {Lysozyme as a cotreatment during antibiotics use against vaginal infections: An in vitro study on Gardnerella vaginalis biofilm models.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {19}, number = {2}, pages = {101-107}, doi = {10.2436/20.1501.01.268}, pmid = {27845497}, issn = {1139-6709}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Female ; Gardnerella vaginalis/*drug effects ; Humans ; Muramidase/*therapeutic use ; Vaginosis, Bacterial/*drug therapy ; }, abstract = {Bacterial vaginoses are frequent in women, most of them involving Gardnerella vaginalis. In more than 50% of the cases, usual antibiotic treatments are not capable of eliminating completely the infection, leading to recurrent vaginosis. In addition to the appearance of antibiotic resistance, recurrence can be due to the development of a biofilm by G. vaginalis. In vitro experiments on G. vaginalis biofilms showed that the biofilm protected bacteria from the antibiotic clindamycin. Also, recombinant human lysozyme (rhLys) was able to both degrade biofilms and prevent their formation. This degradation effect persisted whenever other vaginal commensal or pathogenic microorganisms were added to the culture and on each tested clinical biofilm-producing strain of G. vaginalis. The co-administration of rhLys and clindamycin or metronidazole improved both antibiotics' efficiency and lysozyme-driven biofilm degradation. The comparison of both clindamycin and metronidazole antibacterial spectra showed that metronidazole was preferable to treat vaginosis. This suggests that human lysozyme could be added as an anti-biofilm cotreatment to vaginal antibiotherapy, preferably metronidazole, against Gardnerella vaginalis infection in vivo. [Int Microbiol 19(2): 101-107 (2016)].}, } @article {pmid27845335, year = {2016}, author = {Lin, CS and Tsai, YH and Chang, CJ and Tseng, SF and Wu, TR and Lu, CC and Wu, TS and Lu, JJ and Horng, JT and Martel, J and Ojcius, DM and Lai, HC and Young, JD}, title = {An iron detection system determines bacterial swarming initiation and biofilm formation.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36747}, pmid = {27845335}, issn = {2045-2322}, mesh = {Bacterial Physiological Phenomena ; Bacterial Proteins/genetics/metabolism/*physiology ; *Biofilms ; Coumarins/metabolism ; Flagella/genetics/metabolism/physiology ; Gene Expression Regulation, Bacterial ; Iron/*metabolism ; Models, Biological ; Serratia marcescens/genetics/metabolism/*physiology ; Signal Transduction/genetics/physiology ; }, abstract = {Iron availability affects swarming and biofilm formation in various bacterial species. However, how bacteria sense iron and coordinate swarming and biofilm formation remains unclear. Using Serratia marcescens as a model organism, we identify here a stage-specific iron-regulatory machinery comprising a two-component system (TCS) and the TCS-regulated iron chelator 2-isocyano-6,7-dihydroxycoumarin (ICDH-Coumarin) that directly senses and modulates environmental ferric iron (Fe[3+]) availability to determine swarming initiation and biofilm formation. We demonstrate that the two-component system RssA-RssB (RssAB) directly senses environmental ferric iron (Fe[3+]) and transcriptionally modulates biosynthesis of flagella and the iron chelator ICDH-Coumarin whose production requires the pvc cluster. Addition of Fe[3+], or loss of ICDH-Coumarin due to pvc deletion results in prolonged RssAB signaling activation, leading to delayed swarming initiation and increased biofilm formation. We further show that ICDH-Coumarin is able to chelate Fe[3+] to switch off RssAB signaling, triggering swarming initiation and biofilm reduction. Our findings reveal a novel cellular system that senses iron levels to regulate bacterial surface lifestyle.}, } @article {pmid27845276, year = {2017}, author = {García-Alvarez, R and Izquierdo-Barba, I and Vallet-Regí, M}, title = {3D scaffold with effective multidrug sequential release against bacteria biofilm.}, journal = {Acta biomaterialia}, volume = {49}, number = {}, pages = {113-126}, doi = {10.1016/j.actbio.2016.11.028}, pmid = {27845276}, issn = {1878-7568}, support = {694160/ERC_/European Research Council/International ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Body Fluids/chemistry ; Calcification, Physiologic/drug effects ; Cell Line ; *Drug Liberation ; Kinetics ; Levofloxacin/pharmacology ; Mice ; Microbial Sensitivity Tests ; Osteoblasts/cytology/drug effects/ultrastructure ; Rifampin/pharmacology ; Tissue Scaffolds/*chemistry ; Vancomycin/pharmacology ; X-Ray Diffraction ; }, abstract = {UNLABELLED: Bone infection is a feared complication following surgery or trauma that remains as an extremely difficult disease to deal with. So far, the outcome of therapy could be improved with the design of 3D implants, which combine the merits of osseous regeneration and local multidrug therapy so as to avoid bacterial growth, drug resistance and the feared side effects. Herein, hierarchical 3D multidrug scaffolds based on nanocomposite bioceramic and polyvinyl alcohol (PVA) prepared by rapid prototyping with an external coating of gelatin-glutaraldehyde (Gel-Glu) have been fabricated. These 3D scaffolds contain three antimicrobial agents (rifampin, levofloxacin and vancomycin), which have been localized in different compartments of the scaffold to obtain different release kinetics and more effective combined therapy. Levofloxacin was loaded into the mesopores of nanocomposite bioceramic part, vancomycin was localized into PVA biopolymer part and rifampin was loaded in the external coating of Gel-Glu. The obtained results show an early and fast release of rifampin followed by sustained and prolonged release of vancomycin and levofloxacin, respectively, which are mainly governed by the progressive in vitro degradability rate of these scaffolds. This combined therapy is able to destroy Gram-positive and Gram-negative bacteria biofilms as well as inhibit the bacteria growth. In addition, these multifunctional scaffolds exhibit excellent bioactivity as well as good biocompatibility with complete cell colonization of preosteoblast in the entire surface, ensuring good bone regeneration. These findings suggest that these hierarchical 3D multidrug scaffolds are promising candidates as platforms for local bone infection therapy.

STATEMENT OF SIGNIFICANCE: The present study is focused in finding an adequate therapeutic solution for the treatment of bone infection based on 3D multifunctional scaffolds, which combines the merits of osseous regeneration and local multidrug delivery. These 3D multidrug scaffolds, containing rifampin, levofloxacin and vancomycin, localized in different compartments to achieve different release kinetics. These 3D multidrug scaffolds displays an early and fast release of rifampin followed by sustained and prolonged release of vancomycin and levofloxacin, which are able to destroy Staphylococcus and Escherichia biofilms as well as inhibit bacteria growth in very short time periods. This new combined therapy approach involving the sequential delivery of antibiofilms with antibiotics constitutes an excellent and promising alternative for bone infection treatment.}, } @article {pmid27842452, year = {2017}, author = {Adnan, M and Sousa, AM and Machado, I and Pereira, MO and Khan, S and Morton, G and Hadi, S}, title = {Role of bolA and rpoS genes in biofilm formation and adherence pattern by Escherichia coli K-12 MG1655 on polypropylene, stainless steel, and silicone surfaces.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {64}, number = {2}, pages = {179-189}, doi = {10.1556/030.63.2016.018}, pmid = {27842452}, issn = {1217-8950}, mesh = {Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Escherichia coli K12/genetics/*physiology ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Polypropylenes/*chemistry ; Sigma Factor/genetics/metabolism ; Silicones/chemistry ; Stainless Steel/*chemistry ; Transcription Factors/genetics/*metabolism ; }, abstract = {Escherichia coli has developed sophisticated means to sense, respond, and adapt in stressed environment. It has served as a model organism for studies in molecular genetics and physiology since the 1960s. Stress response genes are induced whenever a cell needs to adapt and survive under unfavorable growth conditions. Two of the possible important genes are rpoS and bolA. The rpoS gene has been known as the alternative sigma (σ) factor, which controls the expression of a large number of genes, which are involved in responses to various stress factors as well as transition to stationary phase from exponential form of growth. Morphogene bolA response to stressed environment leads to round morphology of E. coli cells, but little is known about its involvement in biofilms and its development or maintenance. This study has been undertaken to address the adherence pattern and formation of biofilms by E. coli on stainless steel, polypropylene, and silicone surfaces after 24 h of growth at 37 °C. Scanning electron microscopy was used for direct examination of the cell attachment and biofilm formation on various surfaces and it was found that, in the presence of bolA, E. coli cells were able to attach to the stainless steel and silicone very well. By contrast, polypropylene surface was not found to be attractive for E. coli cells. This indicates that bolA responded and can play a major role in the presence and absence of rpoS in cell attachment.}, } @article {pmid27842343, year = {2016}, author = {Hong, S and Jang, J}, title = {Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {117}, pages = {}, pmid = {27842343}, issn = {1940-087X}, mesh = {*Aerosols ; *Biofilms ; *Carbon Dioxide ; Decontamination/*methods ; Nitrogen ; Stainless Steel ; }, abstract = {Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p > 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.}, } @article {pmid27841027, year = {2016}, author = {Townsend, EM and Sherry, L and Rajendran, R and Hansom, D and Butcher, J and Mackay, WG and Williams, C and Ramage, G}, title = {Development and characterisation of a novel three-dimensional inter-kingdom wound biofilm model.}, journal = {Biofouling}, volume = {32}, number = {10}, pages = {1259-1270}, doi = {10.1080/08927014.2016.1252337}, pmid = {27841027}, issn = {1029-2454}, mesh = {Anti-Infective Agents/administration & dosage/*pharmacology/therapeutic use ; Biofilms/drug effects/*growth & development ; Candida albicans/drug effects/*physiology ; Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry ; *Models, Biological ; Pseudomonas aeruginosa/drug effects/*physiology ; Staphylococcus aureus/drug effects/*physiology ; Wound Healing/drug effects ; Wound Infection/drug therapy/microbiology ; }, abstract = {Chronic diabetic foot ulcers are frequently colonised and infected by polymicrobial biofilms that ultimately prevent healing. This study aimed to create a novel in vitro inter-kingdom wound biofilm model on complex hydrogel-based cellulose substrata to test commonly used topical wound treatments. Inter-kingdom triadic biofilms composed of Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus were shown to be quantitatively greater in this model compared to a simple substratum when assessed by conventional culture, metabolic dye and live dead qPCR. These biofilms were both structurally complex and compositionally dynamic in response to topical therapy, so when treated with either chlorhexidine or povidone iodine, principal component analysis revealed that the 3-D cellulose model was minimally impacted compared to the simple substratum model. This study highlights the importance of biofilm substratum and inclusion of relevant polymicrobial and inter-kingdom components, as these impact penetration and efficacy of topical antiseptics.}, } @article {pmid27840623, year = {2016}, author = {Dubois-Brissonnet, F and Trotier, E and Briandet, R}, title = {The Biofilm Lifestyle Involves an Increase in Bacterial Membrane Saturated Fatty Acids.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1673}, pmid = {27840623}, issn = {1664-302X}, abstract = {Biofilm formation on contact surfaces contributes to persistence of foodborne pathogens all along the food and feed chain. The specific physiological features of bacterial cells embedded in biofilms contribute to their high tolerance to environmental stresses, including the action of antimicrobial compounds. As membrane lipid adaptation is a vital facet of bacterial response when cells are submitted to harsh or unstable conditions, we focused here on membrane fatty acid composition of biofilm cells as compared to their free-growing counterparts. Pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium) were cultivated in planktonic or biofilm states and membrane fatty acid analyses were performed on whole cells in both conditions. The percentage of saturated fatty acids increases in biofilm cells in all cases, with a concomitant decrease of branched-chain fatty acids for Gram-positive bacteria, or with a decrease in the sum of other fatty acids for Gram-negative bacteria. We propose that increased membrane saturation in biofilm cells is an adaptive stress response that allows bacteria to limit exchanges, save energy, and survive. Reprogramming of membrane fluidity in biofilm cells might explain specific biofilm behavior including bacterial recalcitrance to biocide action.}, } @article {pmid27839679, year = {2017}, author = {Hamano, H and Nakamura, S and Hayakawa, J and Miyashita, H and Harayama, S}, title = {Biofilm-based photobioreactor absorbing water and nutrients by capillary action.}, journal = {Bioresource technology}, volume = {223}, number = {}, pages = {307-311}, doi = {10.1016/j.biortech.2016.10.088}, pmid = {27839679}, issn = {1873-2976}, mesh = {Absorption, Physicochemical ; Batch Cell Culture Techniques/*methods ; *Biofilms/growth & development ; Biomass ; *Capillary Action ; Chlorophyta/growth & development/metabolism ; *Food ; Light ; Photobioreactors/*microbiology ; Water/*metabolism ; }, abstract = {Cells of the unicellular green alga, "Pseudochoricystis ellipsoidea", were uniformly spread on a cellulosic sheet or on a polytetrafluoroethylene (PTFE) membrane sheet superimposed on a cellulosic sheet at a density of 3.5-5.0gdry weight per m[2], and the sheet was adhered to an inverted V-shaped acrylic plate of 10cm in height. Several acrylic plates were placed side by side on a tray containing liquid medium at a depth of 0.6cm, and illuminated from above with a light intensity of 300-340μmolm[-2]s[-1]. Water and nutrients were supplied to cells by capillary action through the cellulosic sheet. Footprint biomass productivities of cells grown in atmospheric CO2 on this photobioreactor were 8-10gm[-2]day[-1]. This cultivation system is strongly energy- and labor-saving as it does not require mixing of culture fluid, irrigation of medium, and delivery of CO2-enriched air.}, } @article {pmid27838956, year = {2017}, author = {Gulati, P and Singh, P and Chatterjee, AK and Ghosh, M}, title = {Monitoring of biofilm aging in a Sphingomonas sp. strain from public drinking water sites through changes in capacitance.}, journal = {Environmental technology}, volume = {38}, number = {18}, pages = {2344-2351}, doi = {10.1080/09593330.2016.1260164}, pmid = {27838956}, issn = {1479-487X}, mesh = {*Biofilms ; *Drinking Water ; Electric Capacitance ; *Sphingomonas ; }, abstract = {This study reports the applicability of a capacitance-based technique for evaluating the biofilm progression of Sphingomonas sp. One hundred and forty isolates of Sphingomonas were screened from public drinking water sites, and one potential strain with biofilm-forming ability was used for the study. The biofilm production by this strain was established in microtiter plates and aluminum coupons. The standard biofilm-forming strain Sphingomonas terrae MTCC 7766 was used for comparison. Changes in biofilm were analyzed by energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM). Capacitance values were measured at 1, 100 and 200 kHz frequency; however, 1 kHz was selected since resulted in reproducible values, which could be correlated to biofilm age measured as dry weight over a time of 96 h (4 days) depicting the biofilm growth/progression over time. The EDX, SEM and capacitance values obtained in parallel indicated the related physiological profile usually displayed by biofilms upon growth, suggesting authenticity to the observed capacitance profile. The results of this study demonstrated the feasibility of a capacitance-based method for analyzing biofilm development/progression by Sphingomonas sp. and suggested a simple approach for developing an online system to detect biofilms by this opportunistic pathogen of concern in drinking water.}, } @article {pmid27838734, year = {2017}, author = {Almeida, FA and Pimentel-Filho, NJ and Pinto, UM and Mantovani, HC and Oliveira, LL and Vanetti, MC}, title = {Acyl homoserine lactone-based quorum sensing stimulates biofilm formation by Salmonella Enteritidis in anaerobic conditions.}, journal = {Archives of microbiology}, volume = {199}, number = {3}, pages = {475-486}, doi = {10.1007/s00203-016-1313-6}, pmid = {27838734}, issn = {1432-072X}, mesh = {4-Butyrolactone/*analogs & derivatives/pharmacology ; Anaerobiosis ; Biofilms/*drug effects ; Homoserine/*analogs & derivatives/pharmacology ; *Quorum Sensing ; Salmonella enteritidis/*drug effects/*physiology ; }, abstract = {Quorum sensing regulates a variety of phenotypes in bacteria including the production of virulence factors. Salmonella spp. have quorum sensing systems mediated by three autoinducers (AI-1, AI-2, and AI-3). The AI-1-mediated system is incomplete in that the bacterium relies on the synthesis of signaling molecules by other microorganisms. This study aimed to evaluate the influence of the AI-1 N-dodecanoyl-DL-homoserine lactone (C12-HSL) on the growth, motility, adhesion, and biofilm formation of Salmonella enterica serovar Enteritidis PT4 578 on a polystyrene surface. Experiments were conducted at 37 °C in anaerobic tryptone soy broth supplemented with C12-HSL and/or a mixture of four synthetic furanones, at the concentration of 50 nM each. The planktonic growth, adhesion, swarming, and twitching motility were not altered in the presence of C12-HSL and/or furanones under anaerobic conditions. However, C12-HSL induced biofilm formation after 36 h of cultivation as determined by quantification of biofilm formation, by enumeration of adhered cells to polystyrene coupons, and finally by imaging the presence of multilayered cells on an epifluorescence microscope. When furanones were present in the medium, an antagonistic effect against C12-HSL on the biofilm development was observed. The results demonstrate an induction of biofilm formation in Salmonella Enteritidis by AI-1 under anaerobic conditions. Considering that Salmonella does not produce AI-1 but respond to it, C12-HSL synthesized by other bacterial species could trigger biofilm formation by this pathogen in conditions that are relevant for its pathogenesis.}, } @article {pmid27838508, year = {2017}, author = {Cheng, X and Liu, J and Li, J and Zhou, X and Wang, L and Liu, J and Xu, X}, title = {Comparative effect of a stannous fluoride toothpaste and a sodium fluoride toothpaste on a multispecies biofilm.}, journal = {Archives of oral biology}, volume = {74}, number = {}, pages = {5-11}, doi = {10.1016/j.archoralbio.2016.10.030}, pmid = {27838508}, issn = {1879-1506}, mesh = {Biofilms/classification/*drug effects ; Drug Screening Assays, Antitumor ; In Situ Hybridization, Fluorescence/methods ; Microbial Viability/drug effects ; Models, Biological ; Porphyromonas gingivalis/drug effects/growth & development ; Real-Time Polymerase Chain Reaction/methods ; Sodium Fluoride/*antagonists & inhibitors ; Species Specificity ; Streptococcus mutans/drug effects/growth & development ; Streptococcus sanguis/drug effects/growth & development ; Time Factors ; Tin Fluorides/*antagonists & inhibitors ; Toothpastes/chemistry/*pharmacology ; }, abstract = {OBJECTIVES: This paper aimed to compare the mode of action of a stannous fluoride-containing toothpaste with a conventional sodium fluoride-containing toothpaste on anti-biofilm properties.

METHODS: A three-species biofilm model that consists of Streptococcus mutans, Streptococcus sanguinis and Porphyromonas gingivalis was established to compare the anti-biofilm properties of a stannous fluoride-containing toothpaste (CPH), a conventional sodium fluoride-containing toothpaste (CCP) and a negative control (PBS). The 48h biofilms were subjected to two-minute episodes of treatment with test agents twice a day for 5 consecutive days. Crystal violet staining and XTT assays were used to evaluate the biomass and viability of the treated biofilm. Live/dead staining and bacteria/extracellular polysaccharides (EPS) double-staining were used to visualize the biofilm structure and to quantify microbial/extracellular components of the treated biofilms. Species-specific fluorescent in situ hybridization and quantitative polymerase chain reaction (qPCR) were used to analyze microbial composition of the biofilms after treatment.

RESULTS: The biomass and viability of the biofilms were significantly reduced after CPH toothpaste treatment. The inhibitory effect was further confirmed by the live/dead staining. The EPS amounts of the three-species biofilm were significantly reduced by CCP and CPH treatments, and CPH toothpaste demonstrated significant inhibition on EPS production. More importantly, CPH toothpaste significantly suppressed S. mutans and P. gingvalis, and enriched S. sanguinis in the three-species biofilm. In all experiments CPH had a significantly greater effect than CCP (p<0.05) and CCP had a greater effect than PBS (p<0.05).

CONCLUSIONS: Stannous fluoride-containing toothpaste not only showed better inhibitory effect against oral microbial biofilm, but was also able to modulate microbial composition within multi-species biofilm compared with conventional sodium fluoride-containing toothpaste.}, } @article {pmid27838185, year = {2016}, author = {De Vita, D and Simonetti, G and Pandolfi, F and Costi, R and Di Santo, R and D'Auria, FD and Scipione, L}, title = {Exploring the anti-biofilm activity of cinnamic acid derivatives in Candida albicans.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {26}, number = {24}, pages = {5931-5935}, doi = {10.1016/j.bmcl.2016.10.091}, pmid = {27838185}, issn = {1464-3405}, mesh = {Antifungal Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/metabolism ; Cinnamates/chemical synthesis/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Structure-Activity Relationship ; }, abstract = {Some compounds, characterized by phenylethenyl moiety, such as methyl cinnamate and caffeic acid phenethyl ester, are able to inhibit C. albicans biofilm formation. On these bases, and as a consequence of our previous work, we synthesized a series of cinnamoyl ester and amide derivatives in order to evaluate them for the activity against C. albicans biofilm and planktonically grown cells. The most active compounds 7 and 8 showed ⩾50% biofilm inhibition concentrations (BMIC50) of 2μg/mL and 4μg/mL respectively, against C. albicans biofilm formation; otherwise, 7 showed an interesting activity also against mature biofilm, with BMIC50 of 8μg/mL.}, } @article {pmid27836761, year = {2016}, author = {Tanwar, A and Chawla, R and Chakotiya, AS and Thakur, P and Goel, R and Basu, M and Arora, R and Khan, HA}, title = {Effect of Holarrhena antidysentrica (Ha) and Andrographis paniculata (Ap) on the biofilm formation and cell membrane integrity of opportunistic pathogen Salmonella typhimurium.}, journal = {Microbial pathogenesis}, volume = {101}, number = {}, pages = {76-82}, doi = {10.1016/j.micpath.2016.11.001}, pmid = {27836761}, issn = {1096-1208}, mesh = {Andrographis/*chemistry ; Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Membrane/*drug effects/physiology ; Holarrhena/*chemistry ; Permeability/drug effects ; Phytochemicals/isolation & purification/pharmacology ; Plant Extracts/isolation & purification/*pharmacology ; Propidium/analysis ; Salmonella typhimurium/*drug effects/physiology ; Spectrum Analysis ; Staining and Labeling ; }, abstract = {Increasing occurrence of gastroenteritis outbreaks caused by food borne opportunistic microorganisms has become a major problem in food industry as well as in immunocompromised host. Antimicrobial agents are losing their efficacy due to increase in the microbial resistance. For such reasons, conventional treatment has become limited to manage the infections state. Need of the hour is to instigate the search for safer holistic alternatives. The present study was hence conducted to assess the antibiofilm effect and mode of action of aquo alcoholic extracts of Holarrhena antidysentrica (Ha) and Andrographis paniculata (Ap) against the Salmonella enterica serovar typhimurium. Both the extracts were screened for the presence of phytocompounds followed by the characterization using Attenuated Total Reflection (ATR) infrared spectroscopy and bioactivity finger print analysis. Anti-biofilm assays were determined to test the potential of both extracts to inhibit the biofilm formation, while Propidium Iodide (PI) uptake analysis revealed that cell membrane was damaged by the exposure of nutraceuticals for 1 h. This study has demonstrated that both nutraceuticals have anti-biofilm and antimicrobial activity perturbing the membrane integrity of food-borne S. typhimurium and could be used as curative remedy to control the food borne microbial infection.}, } @article {pmid27836632, year = {2017}, author = {Haraga, I and Abe, S and Jimi, S and Kiyomi, F and Yamaura, K}, title = {Increased biofilm formation ability and accelerated transport of Staphylococcus aureus along a catheter during reciprocal movements.}, journal = {Journal of microbiological methods}, volume = {132}, number = {}, pages = {63-68}, doi = {10.1016/j.mimet.2016.11.003}, pmid = {27836632}, issn = {1872-8359}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Catheters/*microbiology ; Humans ; Movement ; Skin/microbiology ; Staphylococcus aureus/*isolation & purification ; }, abstract = {Staphylococcus spp. is a major cause of device-related infections. However, the mechanisms of deep-tissue infection by staphylococci from the skin surface remain unclear. We performed in vitro experiments to determine how staphylococci are transferred from the surface to the deeper layers of agar along the catheter for different strains of Staphylococcus aureus with respect to bacterial concentrations, catheter movements, and biofilm formation. We found that when 5-mm reciprocal movements of the catheter were repeated every 8h, all catheter samples of S. aureus penetrated the typical distance of 50mm from the skin to the epidural space. The number of reciprocal catheter movements and the depth of bacterial growth were correlated. A greater regression coefficient for different strains implied faster bacterial growth. Enhanced biofilm formation by different strains implied larger regression coefficients. Increased biofilm formation ability may accelerate S. aureus transport along a catheter due to physical movements by patients.}, } @article {pmid27834106, year = {2016}, author = {Salas-Jara, MJ and Sanhueza, EA and Retamal-Díaz, A and González, C and Urrutia, H and García, A}, title = {Probiotic Lactobacillus fermentum UCO-979C biofilm formation on AGS and Caco-2 cells and Helicobacter pylori inhibition.}, journal = {Biofouling}, volume = {32}, number = {10}, pages = {1245-1257}, doi = {10.1080/08927014.2016.1249367}, pmid = {27834106}, issn = {1029-2454}, mesh = {*Antibiosis ; Bacterial Adhesion ; Biofilms/*growth & development ; Caco-2 Cells ; Colonic Neoplasms/microbiology ; Helicobacter pylori/drug effects/*growth & development ; Humans ; Lacticaseibacillus casei/metabolism/physiology ; Limosilactobacillus fermentum/metabolism/*physiology ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/analysis/pharmacology ; *Probiotics/pharmacology ; Stomach Neoplasms/microbiology ; }, abstract = {The ability of the human isolate Lactobacillus fermentum UCO-979C to form biofilm and synthesize exopolysaccharide on abiotic and biotic models is described. These properties were compared with the well-known Lactobacillus casei Shirota to better understand their anti-Helicobacter pylori probiotic activities. The two strains of lactobacilli synthesized exopolysaccharide as detected by the Dubois method and formed biofilm on abiotic and biotic surfaces visualized by crystal violet staining and scanning electron microscopy. Concomitantly, these strains inhibited H. pylori urease activity by up to 80.4% (strain UCO-979C) and 66.8% (strain Shirota) in gastric adenocarcinoma (AGS) cells, but the two species showed equal levels of inhibition (~84%) in colorectal adenocarcinoma (Caco-2) cells. The results suggest that L. fermentum UCO-979C has probiotic potential against H. pylori infections. However, further analyses are needed to explain the increased activity observed against the pathogen in AGS cells as compared to L. casei Shirota.}, } @article {pmid27834049, year = {2018}, author = {Munoz, G and Fechner, LC and Geneste, E and Pardon, P and Budzinski, H and Labadie, P}, title = {Spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) and transfer to periphytic biofilm in an urban river: case-study on the River Seine.}, journal = {Environmental science and pollution research international}, volume = {25}, number = {24}, pages = {23574-23582}, pmid = {27834049}, issn = {1614-7499}, mesh = {Biofilms ; Environmental Monitoring ; Fluorocarbons/*analysis/chemistry ; France ; Geologic Sediments/analysis ; Paris ; *Periphyton ; Rivers/*chemistry ; Seasons ; Spatio-Temporal Analysis ; Water Pollutants, Chemical/*analysis ; }, abstract = {This study addresses the spatio-temporal dynamics of per and polyfluoroalkyl substances (PFASs) in a highly urbanized freshwater hydrosystem, the Seine River (NW France). The distribution of PFASs between water, sediment, and periphytic biofilm was investigated at three sampling sites along a longitudinal gradient upstream and downstream from the Paris urban area. Seasonal variability was assessed through four sampling campaigns performed under contrasting hydrological conditions. In the dissolved phase, ∑PFASs fluctuated between 2 and 9 ng L[-1] upstream and 6-105 ng L[-1] downstream from Paris. Negative correlations between dissolved PFAS levels and river flow rate were generally observed, corroborating the predominance of point-source PFAS inputs at these sites. 18/19 target PFASs were detected, with a predominance of PFHxS and PFOS (20% of ∑PFASs each), except for the farthest downstream site where 6:2 FTSA was prevalent (35 ± 8% of ∑PFASs), likely reflecting industrial and urban inputs. In biofilms, ∑PFASs fell in the 4-32 ng g[-1] dw range, and substantial bioconcentration factors (BCFs) were reported for PFNA, PFDA, and PFOS (log BCF 2.1-4.3), higher than those of PFHxS or PFOA. BCFs varied inversely with dissolved PFAS levels, potentially pointing to concentration-dependent bioaccumulation. Biofilm community characteristics (C/N ratio) may also be an influential determinant of PFAS bioaccumulation. Graphical abstract ᅟ.}, } @article {pmid27833933, year = {2016}, author = {Ragazzo-Sánchez, JA and González-Estrada, RR and Santana-Martínez, MA and Wacher-Rodarte, MD and Eslava-Campos, CA and Calderón-Santoyo, M}, title = {Data on enterobacteria activity on biofilm formation at surface mango fruit (Mangifera indica L.) cv Ataulfo.}, journal = {Data in brief}, volume = {9}, number = {}, pages = {746-748}, pmid = {27833933}, issn = {2352-3409}, abstract = {Abiotic factors influenced the capacity of the strains to form biofilms. Classification of the adhesion type is related with the optical density measured on the biofilm formation of tested strains. The relationship between the biofilm formation in real values with theoretical values of the strains was used to determine the mechanism involved during mixed cultures.}, } @article {pmid27833792, year = {2016}, author = {Zancopé, BR and Dainezi, VB and Nobre-Dos-Santos, M and Duarte, S and Pardi, V and Murata, RM}, title = {Effects of CO2 laser irradiation on matrix-rich biofilm development formation-an in vitro study.}, journal = {PeerJ}, volume = {4}, number = {}, pages = {e2458}, pmid = {27833792}, issn = {2167-8359}, support = {R00 AT006507/AT/NCCIH NIH HHS/United States ; }, abstract = {BACKGROUND: A carbon dioxide (CO2) laser has been used to morphologically and chemically modify the dental enamel surface as well as to make it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of a CO2 laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO2 laser (λ = 10.6 µM).

METHODS: For this in vitro study, 96 specimens of bovine enamel were employed, which were divided into two groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by one, three and five days under intermittent cariogenic condition in the irradiated and non-irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and, in fifth day, were evaluated by polysaccharides analysis, quantitative real time Polymerase Chain Reaction (PCR) as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test.

RESULTS: The mean of log CFU/mL obtained for the one-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to the CO2 laser, CFU/mL and CFU/dry weight in three day was reduced significantly compared with control group. The difference in the genes expression (Glucosyltransferases (gtfB) and Glucan-binding protein (gbpB)) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with the CO2 laser. Similar morphology was also visible with both treatments; however, the irradiated group revealed evidence of melting and fusion in the specimens.

CONCLUSION: In conclusion, CO2 laser irradiation modifies the energy surface and disrupts the initial biofilm formation.}, } @article {pmid27833601, year = {2016}, author = {Field, D and Seisling, N and Cotter, PD and Ross, RP and Hill, C}, title = {Synergistic Nisin-Polymyxin Combinations for the Control of Pseudomonas Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1713}, pmid = {27833601}, issn = {1664-302X}, abstract = {The emergence and dissemination of multi-drug resistant pathogens is a global concern. Moreover, even greater levels of resistance are conferred on bacteria when in the form of biofilms (i.e., complex, sessile communities of bacteria embedded in an organic polymer matrix). For decades, antimicrobial peptides have been hailed as a potential solution to the paucity of novel antibiotics, either as natural inhibitors that can be used alone or in formulations with synergistically acting antibiotics. Here, we evaluate the potential of the antimicrobial peptide nisin to increase the efficacy of the antibiotics polymyxin and colistin, with a particular focus on their application to prevent biofilm formation of Pseudomonas aeruginosa. The results reveal that the concentrations of polymyxins that are required to effectively inhibit biofilm formation can be dramatically reduced when combined with nisin, thereby enhancing efficacy, and ultimately, restoring sensitivity. Such combination therapy may yield added benefits by virtue of reducing polymyxin toxicity through the administration of significantly lower levels of polymyxin antibiotics.}, } @article {pmid27830437, year = {2017}, author = {de Barros, PP and Rossoni, RD and De Camargo Ribeiro, F and Junqueira, JC and Jorge, AO}, title = {Temporal Profile of Biofilm Formation, Gene Expression and Virulence Analysis in Candida albicans Strains.}, journal = {Mycopathologia}, volume = {182}, number = {3-4}, pages = {285-295}, pmid = {27830437}, issn = {1573-0832}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*genetics/isolation & purification/pathogenicity/*physiology ; Candidiasis/microbiology ; Colony Count, Microbial ; Gene Expression Profiling ; *Gene Expression Regulation, Fungal ; Humans ; Hydrolases/genetics ; Lepidoptera/microbiology ; Survival Analysis ; Time Factors ; Virulence ; Virulence Factors/genetics ; }, abstract = {The characterization of Candida albicans strains with different degrees of virulence became very useful to understand the mechanisms of fungal virulence. Then, the objective of this study was to assess and compare the temporal profiles of biofilms formation, gene expression of ALS1, ALS3, HWP1, BCR1, EFG1, TEC1, SAP5, PLB2 and LIP9 and virulence in Galleria mellonella of C. albicans ATCC18804 and a clinical sample isolated from an HIV-positive patient (CA60). Although the CFU/mL counting was higher in biofilms formed in vitro by ATCC strain, the temporal profile of the analysis of the transcripts of the C. albicans strains was elevated to Ca60 compared to strain ATCC, especially in the genes HWP1, ALS3, SAP5, PLB2 and LIP9 (up regulation). Ca60 was more pathogenic for G. mellonella in the survival assay (p = 0.0394) and hemocytes density (p = 0.0349), agreeing with upregulated genes that encode the expression of hyphae and hydrolase genes of Ca60. In conclusion, the C. albicans strains used in this study differ in the amount of biofilm formation, virulence in vivo and transcriptional profiles of genes analyzed that can change factors associated with colonization, proliferation and survival of C. albicans at different niches. SAP5 and HWP1 were the genes more expressed in the formation of biofilm in vitro.}, } @article {pmid27825734, year = {2017}, author = {Halebeedu Prakash, P and Rajan, V and Gopal, S}, title = {Predominance of SCCmec types IV and V among biofilm producing device-associated Staphylococcus aureus strains isolated from tertiary care hospitals in Mysuru, India.}, journal = {Enfermedades infecciosas y microbiologia clinica}, volume = {35}, number = {4}, pages = {229-235}, doi = {10.1016/j.eimc.2016.09.005}, pmid = {27825734}, issn = {1578-1852}, mesh = {Bacterial Typing Techniques ; *Biofilms ; Cross-Sectional Studies ; Equipment Contamination ; India ; Methicillin-Resistant Staphylococcus aureus/classification/isolation & purification/*physiology ; Tertiary Care Centers ; }, abstract = {INTRODUCTION: Device associated infections caused by Staphylococcus aureus in hospitalised patients is a serious healthcare problem. The present study was designed to determine the prevalence of biofilm-producing MRSA in device-associated infections.

METHODS: Device-associated S. aureus strains (n=200) obtained from two tertiary care hospitals in Mysuru city, India were screened for biofilm production, antibiotic resistance, Panton-Valentine Leucocidin genes, SCCmec-types, spa-types, and intercellular adhesion (icaAD) dependent and independent genes. The efficacy of antibiotics (linezolid, vancomycin and rifampicin) on biofilms was studied using MTT assay, and the results were correlated with the occurrence of ica-dependent and independent factors.

RESULTS: Multidrug resistance was observed in 155 strains (77.5%), and 124 strains (62%) were identified as biofilm producers. Methicillin resistance was identified in 145 strains (72.5%), and SCCmec typing of these isolates revealed high prevalence of type IV and type V. They also showed increased prevalence of pvl gene. icaAD was identified in 65 isolates, with 37 isolates showing both icaAD and ica-independent genes. spa types t852 and t657 were predominantly observed in MRSA isolates. Those isolates that had both ica-dependent and ica-independent genes showed more resistance to the screened antibiotics than the ica-dependent alone.

CONCLUSION: This study reports a high prevalence of SCCmec type IV and V in biofilm producing S. aureus strains isolated from device-associated infections. Increased prevalence of pvl in SCCmec types IV and V strains suggests the role of community associated S. aureus in device-associated infections. The simultaneous presence of ica-dependent and independent genes increased the antibiotic resistance in established biofilms. Thus, S. aureus on medical devices is a potential risk for patients.}, } @article {pmid27823882, year = {2017}, author = {Vermote, A and Brackman, G and Risseeuw, MDP and Coenye, T and Van Calenbergh, S}, title = {Novel hamamelitannin analogues for the treatment of biofilm related MRSA infections-A scaffold hopping approach.}, journal = {European journal of medicinal chemistry}, volume = {127}, number = {}, pages = {757-770}, doi = {10.1016/j.ejmech.2016.10.056}, pmid = {27823882}, issn = {1768-3254}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; *Drug Design ; Drug Evaluation, Preclinical ; Gallic Acid/*analogs & derivatives/chemical synthesis/chemistry/pharmacology ; Hexoses/chemical synthesis/chemistry/*pharmacology ; Ligands ; Methicillin-Resistant Staphylococcus aureus/*drug effects/*physiology ; Microbial Sensitivity Tests ; User-Computer Interface ; }, abstract = {Antimicrobial research is increasingly being focused on the problem of resistance and biofilm formation. Hamamelitannin (HAM) was recently identified as an antimicrobial potentiator for conventional antibiotics towards Staphylococcus aureus. This paper describes the synthesis and biological evaluation of novel hamamelitannin analogues with alternative central scaffolds. Via a ligand-based approach, several interesting compounds with improved synthetic accessibility were identified as potentiators for vancomycin in the treatment of MRSA infections.}, } @article {pmid27822201, year = {2016}, author = {Li, Y and Cao, S and Zhang, L and Lau, GW and Wen, Y and Wu, R and Zhao, Q and Huang, X and Yan, Q and Huang, Y and Wen, X}, title = {A TolC-Like Protein of Actinobacillus pleuropneumoniae Is Involved in Antibiotic Resistance and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1618}, pmid = {27822201}, issn = {1664-302X}, abstract = {Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a significant disease that causes serious economic losses to the swine industry worldwide. Persistent infections caused by bacterial biofilms are recalcitrant to treat because of the particular drug resistance of biofilm-dwelling cells. TolC, a key component of multidrug efflux pumps, are responsible for multidrug resistance (MDR) in many Gram-negative bacteria. In this study, we identified two TolC-like proteins, TolC1 and TolC2, in A. pleuropneumoniae. Deletion of tolC1, but not tolC2, caused a significant reduction in biofilm formation, as well as increased drug sensitivity of both planktonic and biofilm cells. The genetic-complementation of the tolC1 mutation restored the competent biofilm and drug resistance. Besides, biofilm formation was inhibited and drug sensitivity was increased by the addition of phenylalanine-arginine beta-naphthylamide (PAβN), a well-known efflux pump inhibitor (EPI), suggesting a role for EPI in antibacterial strategies toward drug tolerance of A. pleuropneumoniae. Taken together, TolC1 is required for biofilm formation and is a part of the MDR machinery of both planktonic and biofilm cells, which could supplement therapeutic strategies for resistant bacteria and biofilm-related infections of A. pleuropneumoniae clinical isolate SC1516.}, } @article {pmid27821454, year = {2017}, author = {Mihu, MR and Cabral, V and Pattabhi, R and Tar, MT and Davies, KP and Friedman, AJ and Martinez, LR and Nosanchuk, JD}, title = {Sustained Nitric Oxide-Releasing Nanoparticles Interfere with Methicillin-Resistant Staphylococcus aureus Adhesion and Biofilm Formation in a Rat Central Venous Catheter Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {1}, pages = {}, pmid = {27821454}, issn = {1098-6596}, support = {R15 GM117501/GM/NIGMS NIH HHS/United States ; R56 DK087872/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/*drug therapy/microbiology ; Central Venous Catheters ; Chitosan/chemistry/pharmacology ; Delayed-Action Preparations ; Disease Models, Animal ; Female ; Glucose/chemistry ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development/ultrastructure ; Nanoparticles/*administration & dosage/chemistry ; Nitric Oxide/chemical synthesis/*pharmacology ; Oxidation-Reduction ; Plankton/drug effects/growth & development ; Rats ; Rats, Sprague-Dawley ; Sodium Nitrite/chemistry ; Staphylococcal Infections/*drug therapy/microbiology ; }, abstract = {Staphylococcus aureus is frequently isolated in the setting of infections of indwelling medical devices, which are mediated by the microbe's ability to form biofilms on a variety of surfaces. Biofilm-embedded bacteria are more resistant to antimicrobial agents than their planktonic counterparts and often cause chronic infections and sepsis, particularly in patients with prolonged hospitalizations. In this study, we demonstrate that sustained nitric oxide-releasing nanoparticles (NO-np) interfere with S. aureus adhesion and prevent biofilm formation on a rat central venous catheter (CVC) model of infection. Confocal and scanning electron microscopy showed that NO-np-treated staphylococcal biofilms displayed considerably reduced thicknesses and bacterial numbers compared to those of control biofilms in vitro and in vivo, respectively. Although both phenotypes, planktonic and biofilm-associated staphylococci, of multiple clinical strains were susceptible to NO-np, bacteria within biofilms were more resistant to killing than their planktonic counterparts. Furthermore, chitosan, a biopolymer found in the exoskeleton of crustaceans and structurally integrated into the nanoparticles, seems to add considerable antimicrobial activity to the technology. Our findings suggest promising development and translational potential of NO-np for use as a prophylactic or therapeutic against bacterial biofilms on CVCs and other medical devices.}, } @article {pmid27821054, year = {2016}, author = {Osman, KM and Samir, A and Abo-Shama, UH and Mohamed, EH and Orabi, A and Zolnikov, T}, title = {Determination of virulence and antibiotic resistance pattern of biofilm producing Listeria species isolated from retail raw milk.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {263}, pmid = {27821054}, issn = {1471-2180}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cattle ; *Drug Resistance, Bacterial ; Listeria/classification/*drug effects/isolation & purification/*pathogenicity ; Milk/*microbiology ; Virulence ; Virulence Factors/genetics/metabolism ; }, abstract = {BACKGROUND: One of the foodborne pathogens is Listeria monocytogenes, which causes serious invasive illness in elderly and immunocompromised patients, pregnant women, newborns and infants ranking second after salmonellosis because of its high case fatality rate. Listerial cow mastitis marked by abnormal milk, increased cell counts and reduced production has not been reported. Therefore, apparently healthy cows can be reservoirs of L. monocytogenes. A number of 203 udder milk samples from apparently healthy animals (buffalo, n = 100; cow, n = 103) were collected and tested for Listeria. Isolated colonies on the PALCAM agar were Listeria species confirmed according to their biochemical and the Christie-Atkins-Munch-Petersen (CAMP) reactions. The Listeria species pathogenicity of was tested by phosphatidylinositol-specific phospholipase C, DL-alanine-β-naphthylamide HCl, Dalanine-p-nitroanilide tests, chick embryo, mice inoculation tests, Vero cell cytotoxicity and biofilm formation. The virulence-associated genes, hlyA, plcB, actA and iap associated with Listeria were molecularly assayed.

RESULTS: The 17 isolated Listeria spp. represented a prevalence rate of 8.4 %. Of these 3 (1.4 %), 2 (1 %), 5 (2.5 %), 4 (2 %) and 3 (1.5 %) were confirmed as L. monocytogenes, L. innocua, L. welshimeri, L. seelegeri, respectively. While the L. monocytogenes isolate displayed all the four virulence-associated genes, L. seelegeri carried the hlyA gene only. The L. monocytogenes had a strong in vitro affinity to form a biofilm, in particular serotype 4 which is associated with human infections. L. monocytogenes showed resistance for 9/27 antibiotics.

CONCLUSIONS: The biofilm forming capability of the Listeria spps. makes them particularly successful in colonizing surfaces within the host thus being responsible for persistence infections and due to their antimicrobial resistant phenotype that this structure confers. In addition, strains belonging to serotypes associated with human infections and characterized by pathogenic potential (serotype 4) are capable to persist within the processing plants forming biofilm and thus being a medical hazard.}, } @article {pmid27821046, year = {2016}, author = {Horne, SM and Sayler, J and Scarberry, N and Schroeder, M and Lynnes, T and Prüß, BM}, title = {Spontaneous mutations in the flhD operon generate motility heterogeneity in Escherichia coli biofilm.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {262}, pmid = {27821046}, issn = {1471-2180}, support = {R15 AI089403/AI/NIAID NIH HHS/United States ; }, mesh = {*Biofilms ; Escherichia coli/genetics/*physiology ; Escherichia coli Proteins/*genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Mutation ; Operon ; Trans-Activators/*genetics/metabolism ; }, abstract = {BACKGROUND: Heterogeneity and niche adaptation in bacterial biofilm involve changes to the genetic makeup of the bacteria and gene expression control. We hypothesized that i) spontaneous mutations in the flhD operon can either increase or decrease motility and that ii) the resulting motility heterogeneity in the biofilm might lead to a long-term increase in biofilm biomass.

RESULTS: We allowed the highly motile E. coli K-12 strain MC1000 to form seven- and fourteen-day old biofilm, from which we recovered reduced motility isolates at a substantially greater frequency (5.4 %) than from a similar experiment with planktonic bacteria (0.1 %). Biofilms formed exclusively by MC1000 degraded after 2 weeks. In contrast, biofilms initiated with a 1:1 ratio of MC1000 and its isogenic flhD::kn mutant remained intact at 4 weeks and the two strains remained in equilibrium for at least two weeks. These data imply that an 'optimal' biofilm may contain a mixture of motile and non-motile bacteria. Twenty-eight of the non-motile MC1000 isolates contained an IS1 element in proximity to the translational start of FlhD or within the open reading frames for FlhD or FlhC. Two isolates had an IS2 and one isolate had an IS5 in the open reading frame for FlhD. An additional three isolates contained deletions that included the RNA polymerase binding site, five isolates contained point mutations and small deletions in the open reading frame for FlhC. The locations of all these mutations are consistent with the lack of motility and further downstream within the flhD operon than previously published IS elements that increased motility. We believe that the location of the mutation within the flhD operon determines whether the effect on motility is positive or negative. To test the second part of our hypothesis where motility heterogeneity in a biofilm may lead to a long-term increase in biofilm biomass, we quantified biofilm biomass by MC1000, MC1000 flhD::kn, and mixtures of the two strains at ratios of 1:1, 10:1, and 1:10. After 3 weeks, biofilm of the mixed cultures contained up to five times more biomass than biofilm of each of the individual strains.

CONCLUSION: Mutations in the flhD operon can exert positive or negative effects on motility, depending on the site of the mutation. We believe that this is a mechanism to generate motility heterogeneity within E. coli biofilm, which may help to maintain biofilm biomass over extended periods of time.}, } @article {pmid27818282, year = {2017}, author = {Kwiatek, M and Parasion, S and Rutyna, P and Mizak, L and Gryko, R and Niemcewicz, M and Olender, A and Łobocka, M}, title = {Isolation of bacteriophages and their application to control Pseudomonas aeruginosa in planktonic and biofilm models.}, journal = {Research in microbiology}, volume = {168}, number = {3}, pages = {194-207}, doi = {10.1016/j.resmic.2016.10.009}, pmid = {27818282}, issn = {1769-7123}, mesh = {*Biofilms ; Computer Simulation ; Humans ; Microscopy, Electron ; Myoviridae/isolation & purification/physiology ; Plankton ; Podoviridae/isolation & purification/physiology ; Pseudomonas Infections/microbiology/prevention & control/therapy ; Pseudomonas Phages/genetics/*isolation & purification/physiology/ultrastructure ; Pseudomonas aeruginosa/*virology ; }, abstract = {Pseudomonas aeruginosa is frequently identified as a cause of diverse infections and chronic diseases. It forms biofilms and has natural resistance to several antibiotics. Strains of this pathogen resistant to new-generation beta-lactams have emerged. Due to the difficulties associated with treating chronic P. aeruginosa infections, bacteriophages are amongst the alternative therapeutic options being actively researched. Two obligatorily lytic P. aeruginosa phages, vB_PaeM_MAG1 (MAG1) and vB_PaeP_MAG4 (MAG4), have been isolated and characterized. These phages belong to the PAK_P1likevirus genus of the Myoviridae family and the LIT1virus genus of the Podoviridae family, respectively. They adsorb quickly to their hosts (∼90% in 5 min), have a short latent period (15 min), and are stable during storage. Each individual phage propagated in approximately 50% of P. aeruginosa strains tested, which increased to 72.9% when phages were combined into a cocktail. While MAG4 reduced biofilm more effectively after a short time of treatment, MAG1 was more effective after a longer time and selected less for phage-resistant clones. A MAG1-encoded homolog of YefM antitoxin of the bacterial toxin-antitoxin system may contribute to the superiority of MAG1 over MAG4.}, } @article {pmid27818159, year = {2017}, author = {Choudhary, P and Prajapati, SK and Kumar, P and Malik, A and Pant, KK}, title = {Development and performance evaluation of an algal biofilm reactor for treatment of multiple wastewaters and characterization of biomass for diverse applications.}, journal = {Bioresource technology}, volume = {224}, number = {}, pages = {276-284}, doi = {10.1016/j.biortech.2016.10.078}, pmid = {27818159}, issn = {1873-2976}, mesh = {*Biofilms ; Biomass ; Microalgae/*physiology ; Waste Management/*methods ; *Wastewater ; }, abstract = {A modified algal biofilm reactor (ABR) was developed and assessed for high biomass productivity and treatment potential using variable strength wastewaters with accumulation of specialized bio-products. The nonwoven spun bond fabric (70GSM) was selected as suitable biofilm support on the basis of attachment efficiency, durability and ease of harvesting. The biomass productivity achieved by ABR biofilms were 4gm[-2]d[-1], 3.64gm[-2]d[-1] and 3.10gm[-2]d[-1] when grown in livestock wastewater (LSW), domestic grey water (DGW) and anaerobically digested slurry (ADS), respectively. Detailed characterization of wastewater grown biomass showed specific distribution of biomolecules into high lipid (38%) containing biomass (DGW grown) and high protein (44%) biomass (LSW and ADS grown). The feasibility assessment of ABR in terms of net energy return (>1) favored its application in an integrated system for treatment and recycling of rural wastewaters with simultaneous production of biomethane, livestock feed supplement and bio fertilizers.}, } @article {pmid27816975, year = {2017}, author = {Chen, H and Cao, J and Zhou, C and Liu, H and Zhang, X and Zhou, T}, title = {Biofilm Formation Restrained by Subinhibitory Concentrations of Tigecyclin in Acinetobacter baumannii Is Associated with Downregulation of Efflux Pumps.}, journal = {Chemotherapy}, volume = {62}, number = {2}, pages = {128-133}, doi = {10.1159/000450537}, pmid = {27816975}, issn = {1421-9794}, mesh = {Acinetobacter baumannii/*drug effects/physiology ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects/growth & development ; Down-Regulation/*drug effects/physiology ; Humans ; Membrane Transport Proteins/*metabolism ; Microbial Sensitivity Tests/methods ; Minocycline/administration & dosage/*analogs & derivatives ; Tigecycline ; }, abstract = {BACKGROUND: Tigecycline, one of the few therapeutic options against multidrug-resistant Acinetobacter baumannii, reaches subinhibitory serum concentrations only with cautious clinical dosing and pharmacokinetics. Subinhibitory concentrations of tigecycline might induce an A. baumannii biofilm.

METHODS: Biofilm formation was assessed via the crystal violet staining method. We further analyzed the main biofilm components with NaIO4, proteinase K, and DNase. Real-time RT-PCR was applied for quantitative detection of biofilm potential-associated genes.

RESULTS: In this study, A. baumannii proved to be a strong biofilm producer, and we found that proteins and extracellular DNA are crucial components of the A. baumannii biofilm. Quantitative real-time RT-PCR revealed positive correlations between biofilm formation restrained by subinhibitory concentrations of tigecycline and the expression of biofilm potential-associated genes, especially the AdeFGH efflux pump gene.

CONCLUSION: Our results suggest that downregulation of efflux pumps, especially the AdeFGH efflux pump, is probably responsible for the decline in biofilm formation in A. baumannii treated with subinhibitory concentrations of tigecyclin.}, } @article {pmid27815566, year = {2017}, author = {Dash, HR and Basu, S and Das, S}, title = {Evidence of mercury trapping in biofilm-EPS and mer operon-based volatilization of inorganic mercury in a marine bacterium Bacillus cereus BW-201B.}, journal = {Archives of microbiology}, volume = {199}, number = {3}, pages = {445-455}, doi = {10.1007/s00203-016-1317-2}, pmid = {27815566}, issn = {1432-072X}, mesh = {Bacillus cereus/*genetics/*metabolism ; *Biofilms ; Mercury/*metabolism ; Operon/*genetics ; Oxidoreductases/*genetics/metabolism ; Volatilization ; }, abstract = {Biofilm-forming mercury-resistant marine bacterium Bacillus cereus BW-201B has been explored to evident that the bacterial biofilm-EPS (exopolymers) trap inorganic mercury but subsequently release EPS-bound mercury for induction of mer operon-mediated volatilization of inorganic mercury. The isolate was able to tolerate 50 ppm of mercury and forms biofilm in presence of mercury. mer operon-mediated volatilization was confirmed, and -SH was found to be the key functional group of bacterial EPS responsible for mercury binding. Biofilm-EPS-bound mercury was found to be internalized to the bacterial system as confirmed by reversible conformational change of -SH group and increased expression level of merA gene in a timescale experiment. Biofilm-EPS trapped Hg after 24 h of incubation, and by 96 h, the volatilization process reaches to its optimum confirming the internalization of EPS-bound mercury to the bacterial cells. Biofilm disintegration at the same time corroborates the results.}, } @article {pmid27815042, year = {2017}, author = {Li, Y and Liu, H and Yan, F and Su, D and Wang, Y and Zhou, H}, title = {High-calorific biogas production from anaerobic digestion of food waste using a two-phase pressurized biofilm (TPPB) system.}, journal = {Bioresource technology}, volume = {224}, number = {}, pages = {56-62}, doi = {10.1016/j.biortech.2016.10.070}, pmid = {27815042}, issn = {1873-2976}, mesh = {Anaerobiosis ; Biofilms ; *Biofuels ; *Bioreactors ; Conservation of Energy Resources ; Digestion ; Food ; Hydrogen-Ion Concentration ; Methane/*biosynthesis ; Pressure ; }, abstract = {To obtain high calorific biogas via anaerobic digestion without additional upgrading equipment, a two-phase pressurized biofilm system was built up, including a conventional continuously stirred tank reactor and a pressurized biofilm anaerobic reactor (PBAR). Four different pressure levels (0.3, 0.6, 1.0 and 1.7MPa) were applied to the PBAR in sequence, with the organic loading rate maintained at 3.1g-COD/L/d. Biogas production, gas composition, process stability parameters were measured. Results showed that with the pressure increasing from 0.3MPa to 1.7MPa, the pH value decreased from 7.22±0.19 to 6.98±0.05, the COD removal decreased from 93.0±0.9% to 79.7±1.2% and the methane content increased from 80.5±1.5% to 90.8±0.8%. Biogas with higher calorific value of 36.2MJ/m[3] was obtained at a pressure of 1.7MPa. Pressure showed a significant effect on biogas production and gas quality in methanogenesis reactor.}, } @article {pmid27812616, year = {2016}, author = {Silva, SS and Ribeiro, MO and Gomes, FI and Chaves, HV and Silva, AA and Zanin, IC and Barbosa, FC}, title = {Occurrence and antimicrobial susceptibility of enteric rods and pseudomonads isolated from the dental prostheses biofilm.}, journal = {Journal of applied oral science : revista FOB}, volume = {24}, number = {5}, pages = {462-471}, pmid = {27812616}, issn = {1678-7765}, mesh = {Adult ; Age Distribution ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Dental Prosthesis/*microbiology ; Drug Resistance, Multiple, Bacterial ; Enterobacteriaceae/drug effects/*isolation & purification ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pseudomonas/drug effects/*isolation & purification ; Reference Values ; Sex Distribution ; Statistics, Nonparametric ; Time Factors ; }, abstract = {OBJECTIVE:: To determine the occurrence and the in vitro antimicrobial susceptibility of enteric rods and pseudomonads from the denture biofilm of 52 subjects at the Center for Dental Specialties of Sobral/ Ceara, Brazil.

MATERIAL AND METHODS:: Denture biofilm was collected and samples plated on MacConkey agar. The isolated bacterial colonies were identified using the BBL Crystal enteric/non-fermenter system. Antibiotic bacterial susceptibility was assessed by the disc diffusion method of amoxicillin, amoxicillin/clavulanic acid, doxycycline, tetracycline, tobramycin, imipenem, cefotaxime, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) of cefotaxime, tobramycin, doxycycline, imipenem, and ciprofloxacin was determined for 40 species by E-test.

RESULTS:: 34 subjects (65.4%) harbored enteric rods in their prostheses. Klebsiella pneumoniae (26.5%), Escherichia coli (23.5%), and Enterobacter aerogenes (23.5%) were the most prevalent species. All organisms were susceptible to ciprofloxacin and most species were resistant to amoxicillin or amoxicillin/clavulanic acid, demonstrating variable sensitivity patterns to other antimicrobials. However, the MIC showed the emergence of strains with reduced sensitivity to ciprofloxacin (MIC90≥3 μg/ mL) and cefotaxime (MIC90≥2 μg/mL).

CONCLUSION:: The findings show high prevalence of nosocomial diseases-related bacterial species and low susceptibility to antimicrobial drugs. Therefore, these results imply caution against the indiscriminate use of broad spectrum antibiotics in dental practice.}, } @article {pmid27812526, year = {2016}, author = {Latorre, JD and Hernandez-Velasco, X and Wolfenden, RE and Vicente, JL and Wolfenden, AD and Menconi, A and Bielke, LR and Hargis, BM and Tellez, G}, title = {Evaluation and Selection of Bacillus Species Based on Enzyme Production, Antimicrobial Activity, and Biofilm Synthesis as Direct-Fed Microbial Candidates for Poultry.}, journal = {Frontiers in veterinary science}, volume = {3}, number = {}, pages = {95}, pmid = {27812526}, issn = {2297-1769}, abstract = {Social concern about misuse of antibiotics as growth promoters (AGP) and generation of multidrug-resistant bacteria have restricted the dietary inclusion of antibiotics in livestock feed in several countries. Direct-fed microbials (DFM) are one of the multiple alternatives commonly evaluated as substitutes of AGP. Sporeformer bacteria from the genus Bacillus have been extensively investigated because of their extraordinary properties to form highly resistant endospores, produce antimicrobial compounds, and synthesize different exogenous enzymes. The purpose of the present study was to evaluate and select Bacillus spp. from environmental and poultry sources as DFM candidates, considering their enzyme production profile, biofilm synthesis capacity, and pathogen-inhibition activity. Thirty-one Bacillus isolates were screened for in vitro relative enzyme activity of amylase, protease, lipase, and phytase using a selective media for each enzyme, with 3/31 strains selected as superior enzyme producers. These three isolates were identified as Bacillus subtilis (1/3), and Bacillus amyloliquefaciens (2/3), based on biochemical tests and 16S rRNA sequence analysis. For evaluation of biofilm synthesis, the generation of an adherent crystal violet-stained ring was determined in polypropylene tubes, resulting in 11/31 strains showing a strong biofilm formation. Moreover, all Bacillus strains were evaluated for growth inhibition activity against Salmonella enterica serovar Enteritidis (26/31), Escherichia coli (28/31), and Clostridioides difficile (29/31). Additionally, in previous in vitro and in vivo studies, these selected Bacillus strains have shown to be resistant to different biochemical conditions of the gastrointestinal tract of poultry. Results of the present study suggest that the selection and consumption of Bacillus-DFM, producing a variable set of enzymes and antimicrobial compounds, may contribute to enhanced performance through improving nutrient digestibility, reducing intestinal viscosity, maintaining a beneficial gut microbiota, and promoting healthy intestinal integrity in poultry.}, } @article {pmid27812354, year = {2016}, author = {Yang, YB and Chen, JQ and Zhao, YL and Bai, JW and Ding, WY and Zhou, YH and Chen, XY and Liu, D and Li, YH}, title = {Sub-MICs of Azithromycin Decrease Biofilm Formation of Streptococcus suis and Increase Capsular Polysaccharide Content of S. suis.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1659}, pmid = {27812354}, issn = {1664-302X}, abstract = {Streptococcus suis (S. suis) caused serious disease symptoms in humans and pigs. S. suis is able to form thick biofilms and this increases the difficulty of treatment. After growth with 1/2 minimal inhibitory concentration (MIC) of azithromycin, 1/4 MIC of azithromycin, or 1/8 MIC of azithromycin, biofilm formation of S. suis dose-dependently decreased in the present study. Furthermore, scanning electron microscopy analysis revealed the obvious effect of azithromycin against biofilm formation of S. suis. Especially, at two different conditions (1/2 MIC of azithromycin non-treated cells and treated cells), we carried out comparative proteomic analyses of cells by using iTRAQ technology. Finally, the results revealed the existence of 19 proteins of varying amounts. Interestingly, several cell surface proteins (such as ATP-binding cassette superfamily ATP-binding cassette transporter (G7SD52), CpsR (K0FG35), Cps1/2H (G8DTL7), CPS16F (E9NQ13), putative uncharacterized protein (G7SER0), NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (G5L259), putative uncharacterized protein (G7S2D6), amino acid permease (B0M0G6), and NsuB (G5L351)) were found to be implicated in biofilm formation. More importantly, we also found that azithromycin affected expression of the genes cps1/2H, cpsR and cps16F. Especially, after growth with 1/2 MIC of azithromycin and 1/4 MIC of azithromycin, the capsular polysaccharide content of S. suis was significantly higher.}, } @article {pmid27753272, year = {2016}, author = {Garcia, SS and Du, Q and Wu, H}, title = {Streptococcus mutans copper chaperone, CopZ, is critical for biofilm formation and competitiveness.}, journal = {Molecular oral microbiology}, volume = {31}, number = {6}, pages = {515-525}, pmid = {27753272}, issn = {2041-1014}, support = {F31 DE024041/DE/NIDCR NIH HHS/United States ; R01 DE017954/DE/NIDCR NIH HHS/United States ; R01 DE022350/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Copper/*metabolism ; Gene Expression Regulation, Bacterial ; Glucosyltransferases/metabolism ; *Microbial Interactions ; Microscopy, Confocal ; Molecular Chaperones/*genetics/*metabolism ; Mutation ; *Operon ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*genetics/pathogenicity/*physiology/ultrastructure ; }, abstract = {The oral cavity is a dynamic environment characterized by hundreds of bacterial species, saliva, and an influx of nutrients and metal ions such as copper. Although there is a physiologic level of copper in the saliva, the oral cavity is often challenged with an influx of copper ions. At high concentrations copper is toxic and must therefore be strictly regulated by pathogens for them to persist and cause disease. The cariogenic pathogen Streptococcus mutans manages excess copper using the copYAZ operon that encodes a negative DNA-binding repressor (CopY), the P1-ATPase copper exporter (CopA), and the copper chaperone (CopZ). These hypothetical roles of the copYAZ operon in regulation and copper transport to receptors led us to investigate their contribution to S. mutans virulence. Mutants defective in the copper chaperone CopZ, but not CopY or CopA, were impaired in biofilm formation and competitiveness against commensal streptococci. Characterization of the CopZ mutant biofilm revealed a decreased secretion of glucosyltransferases and reduced expression of mutacin genes. These data suggest that the function of copZ on biofilm and competitiveness is independent of copper resistance and CopZ is a global regulator for biofilm and other virulence factors. Further characterization of CopZ may lead to the identification of new biofilm pathways.}, } @article {pmid27731909, year = {2017}, author = {Hoffman, C and Eby, J and Gray, M and Heath Damron, F and Melvin, J and Cotter, P and Hewlett, E}, title = {Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro.}, journal = {Molecular microbiology}, volume = {103}, number = {2}, pages = {214-228}, pmid = {27731909}, issn = {1365-2958}, support = {R01 AI018000/AI/NIAID NIH HHS/United States ; R01 AI094991/AI/NIAID NIH HHS/United States ; T32 AI007046/AI/NIAID NIH HHS/United States ; }, mesh = {Adenylate Cyclase Toxin/genetics/*metabolism ; Adhesins, Bacterial/genetics/*metabolism ; Biofilms/*growth & development ; Bordetella bronchiseptica/genetics/*metabolism ; Bordetella pertussis/genetics/metabolism/*physiology ; Hemagglutinins/metabolism ; Virulence Factors, Bordetella/genetics/*metabolism ; }, abstract = {Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous haemagglutinin (FHA), a surface-displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT-FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro. Exogenous ACT inhibits biofilm formation in a concentration-dependent manner and the N-terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C-terminal segment of FHA with ∼650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C-terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host-directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT.}, } @article {pmid27809313, year = {2016}, author = {Zarnowski, R and Sanchez, H and Andes, DR}, title = {Large-scale production and isolation of Candida biofilm extracellular matrix.}, journal = {Nature protocols}, volume = {11}, number = {12}, pages = {2320-2327}, pmid = {27809313}, issn = {1750-2799}, mesh = {*Biofilms ; Candida/*cytology/*physiology ; Cell Fractionation/*methods ; *Extracellular Matrix ; }, abstract = {The extracellular matrix of biofilm is unique to the biofilm lifestyle, and it has key roles in community survival. A complete understanding of the biochemical nature of the matrix is integral to the understanding of the roles of matrix components. This knowledge is a first step toward the development of novel therapeutics and diagnostics to address persistent biofilm infections. Many of the assay methods needed for refined matrix composition analysis require milligram amounts of material that is separated from the cellular components of these complex communities. The protocol described here explains the large-scale production and isolation of the Candida biofilm extracellular matrix. To our knowledge, the proposed procedure is the only currently available approach in the field that yields milligram amounts of biofilm matrix. This procedure first requires biofilms to be seeded in large-surface-area roller bottles, followed by cell adhesion and biofilm maturation during continuous movement of the medium across the surface of the rotating bottle. The formed matrix is then separated from the entire biomass using sonication, which efficiently removes the matrix without perturbing the fungal cell wall. Subsequent filtration, dialysis and lyophilization steps result in a purified matrix product sufficient for biochemical, structural and functional assays. The overall protocol takes ∼11 d to complete. This protocol has been used for Candida species, but, using the troubleshooting guide provided, it could be adapted for other fungi or bacteria.}, } @article {pmid27808313, year = {2016}, author = {Paquet-Mercier, F and Parvinzadeh Gashti, M and Bellavance, J and Taghavi, SM and Greener, J}, title = {Through thick and thin: a microfluidic approach for continuous measurements of biofilm viscosity and the effect of ionic strength.}, journal = {Lab on a chip}, volume = {16}, number = {24}, pages = {4710-4717}, doi = {10.1039/c6lc01101b}, pmid = {27808313}, issn = {1473-0189}, mesh = {*Biofilms ; *Lab-On-A-Chip Devices ; *Osmolar Concentration ; Pseudomonas aeruginosa/drug effects/physiology ; Viscosity ; }, abstract = {Continuous, non-intrusive measurements of time-varying viscosity of Pseudomonas sp. biofilms are made using a microfluidic method that combines video tracking with a semi-empirical viscous flow model. The approach uses measured velocity and height of tracked biofilm segments, which move under the constant laminar flow of a nutrient solution. Following a low viscosity growth stage, rapid thickening was observed. During this stage, viscosity increased by over an order of magnitude in less than ten hours. The technique was also demonstrated as a promising platform for parallel experiments by subjecting multiple biofilm-laden microchannels to nutrient solutions containing NaCl in the range of 0 to 34 mM. Preliminary data suggest a strong relationship between ionic strength and biofilm properties, such as average viscosity and rapid thickening onset time. The technique opens the way for a combinatorial approach to study the response of biofilm viscosity under well-controlled physical, chemical and biological growth conditions.}, } @article {pmid27808174, year = {2016}, author = {Kim, YG and Lee, JH and Gwon, G and Kim, SI and Park, JG and Lee, J}, title = {Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36377}, pmid = {27808174}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans/microbiology ; Disease Models, Animal ; Escherichia coli Infections/drug therapy ; Escherichia coli O157/*drug effects/genetics/pathogenicity/physiology ; Escherichia coli Proteins/genetics ; Eugenol/*pharmacology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Oils, Volatile/*pharmacology ; Plankton ; Plant Oils/pharmacology ; Virulence/drug effects ; }, abstract = {Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC.}, } @article {pmid27806068, year = {2016}, author = {Barai, P and Kumar, A and Mukherjee, PP}, title = {Modeling of Mesoscale Variability in Biofilm Shear Behavior.}, journal = {PloS one}, volume = {11}, number = {11}, pages = {e0165593}, pmid = {27806068}, issn = {1932-6203}, mesh = {Bacterial Adhesion ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Biomechanical Phenomena ; Humans ; *Models, Biological ; Shear Strength ; }, abstract = {Formation of bacterial colonies as biofilm on the surface/interface of various objects has the potential to impact not only human health and disease but also energy and environmental considerations. Biofilms can be regarded as soft materials, and comprehension of their shear response to external forces is a key element to the fundamental understanding. A mesoscale model has been presented in this article based on digitization of a biofilm microstructure. Its response under externally applied shear load is analyzed. Strain stiffening type behavior is readily observed under high strain loads due to the unfolding of chains within soft polymeric substrate. Sustained shear loading of the biofilm network results in strain localization along the diagonal direction. Rupture of the soft polymeric matrix can potentially reduce the intercellular interaction between the bacterial cells. Evolution of stiffness within the biofilm network under shear reveals two regimes: a) initial increase in stiffness due to strain stiffening of polymer matrix, and b) eventual reduction in stiffness because of tear in polymeric substrate.}, } @article {pmid27644984, year = {2016}, author = {Truong, T and Zeng, G and Qingsong, L and Kwang, LT and Tong, C and Chan, FY and Wang, Y and Seneviratne, CJ}, title = {Comparative Ploidy Proteomics of Candida albicans Biofilms Unraveled the Role of the AHP1 Gene in the Biofilm Persistence Against Amphotericin B.}, journal = {Molecular & cellular proteomics : MCP}, volume = {15}, number = {11}, pages = {3488-3500}, pmid = {27644984}, issn = {1535-9484}, mesh = {Amphotericin B/*pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida albicans/drug effects/*genetics/physiology ; Diploidy ; Down-Regulation ; *Drug Resistance, Bacterial ; Fungal Proteins/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Peroxiredoxins/*metabolism ; Polyploidy ; Proteomics/methods ; }, abstract = {Candida albicans is a major fungal pathogen causing lethal infections in immunocompromised patients. C. albicans forms antifungal tolerant biofilms contributing significantly to therapeutic failure. The recently established haploid C. albicans biofilm model provides a new toolbox to uncover the mechanism governing the higher antifungal tolerance of biofilms. Here, we comprehensively examined the proteomics and antifungal susceptibility of standard diploid (SC5314 and BWP17) and stable haploid (GZY792 and GZY803) strains of C. albicans biofilms. Subsequent downstream analyses identified alkyl hydroperoxide reductase 1 (AHP1) as a critical determinant of C. albicans biofilm's tolerance of amphotericin B. At 32 μg/ml of amphotericin B, GZY803 haploid biofilms showed 0.1% of persister population as compared with 1% of the diploid biofilms. AHP1 expression was found to be lower in GZY803 biofilms, and AHP1 overexpression in GZY803 restored the percentage of persister population. Consistently, deleting AHP1 in the diploid strain BWP17 caused a similar increase in amphotericin B susceptibility. AHP1 expression was also positively correlated with the antioxidant potential. Furthermore, C. albicans ira2Δ/Δ biofilms were susceptible to amphotericin B and had a diminished antioxidant capacity. Interestingly, AHP1 overexpression in the ira2Δ/Δ strain restored the antioxidant potential and enhanced the persister population against amphotericin B, and shutting down the AHP1 expression in ira2Δ/Δ biofilms reversed the effect. In conclusion, we provide evidence that the AHP1 gene critically determines the amphotericin B tolerance of C. albicans biofilms possibly by maintaining the persisters' antioxidant capacity. This finding will open up new avenues for developing therapies targeting the persister population of C. albicans biofilms. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD004274.}, } @article {pmid27800149, year = {2016}, author = {Khangholi, M and Jamalli, A}, title = {The Effects of Sugars on the Biofilm Formation of Escherichia coli 185p on Stainless Steel and Polyethylene Terephthalate Surfaces in a Laboratory Model.}, journal = {Jundishapur journal of microbiology}, volume = {9}, number = {9}, pages = {e40137}, pmid = {27800149}, issn = {2008-3645}, abstract = {BACKGROUND: Bacteria utilize various methods in order to live in protection from adverse environmental conditions. One such method involves biofilm formation; however, this formation is dependent on many factors. The type and concentration of substances such as sugars that are present in an environment can be effective facilitators of biofilm formation.

METHODS: First, the physico-chemical properties of the bacteria and the target surface were studied via the MATS and contact angle measurement methods. Additionally, adhesion to different surfaces in the presence of various concentrations of sugars was compared in order to evaluate the effect of these factors on the biofilm formation of Escherichia coli, which represents a major food contaminant.

RESULTS: Results showed that the presence of sugars has no effect on the bacterial growth rate; all three concentrations of sugars were hydrophilic and demonstrated a high affinity toward binding to the surfaces.

CONCLUSIONS: The impact of sugars and other factors on biofilm formation can vary depending on the type of bacteria present.}, } @article {pmid27799219, year = {2017}, author = {Runci, F and Bonchi, C and Frangipani, E and Visaggio, D and Visca, P}, title = {Acinetobacter baumannii Biofilm Formation in Human Serum and Disruption by Gallium.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {1}, pages = {}, pmid = {27799219}, issn = {1098-6596}, mesh = {Acinetobacter baumannii/*drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Gallium/*pharmacology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Biofilm-associated infections caused by Acinetobacter baumannii are extremely recalcitrant to antibiotic treatment. We report that A. baumannii develops a mature biofilm when grown in complement-free human serum (HS). We demonstrate that 16 μM gallium nitrate (GaN) drastically reduces A. baumannii growth and biofilm formation in HS, whereas 64 μM GaN causes massive disruption of preformed A. baumannii biofilm. These findings pave the way to the repurposing of GaN as an antibiofilm agent for A. baumannii.}, } @article {pmid27690228, year = {2016}, author = {Xiao, X and Zhu, WW and Liu, QY and Yuan, H and Li, WW and Wu, LJ and Li, Q and Yu, HQ}, title = {Impairment of Biofilm Formation by TiO2 Photocatalysis through Quorum Quenching.}, journal = {Environmental science & technology}, volume = {50}, number = {21}, pages = {11895-11902}, doi = {10.1021/acs.est.6b03134}, pmid = {27690228}, issn = {1520-5851}, mesh = {Bacterial Proteins ; *Biofilms ; Catalysis ; *Escherichia coli ; Homoserine ; Lactones ; *Quorum Sensing ; *Titanium ; Ultraviolet Rays ; }, abstract = {The release of nanomaterials into the environment, due to their massive production and application today, has caused ecological and health safety concerns. Semiconductor photocatalysts like TiO2 exhibit cytotoxicity to bacterial cells when exposed to UV irradiation. However, information about their impacts on individual or group bacterial behaviors is limited. In this work, the biofilm formation of Escherichia coli K12 in the presence of TiO2 with and without UV irradiation was investigated and biofilm formation was found not to be affected under the sole application of TiO2 or UV irradiation. However, biofilm development was substantially delayed by TiO2 under UV irradiation, although no obvious cytotoxicity to cell growth was observed. The reactive oxygen species photogenerated by TiO2 were found to quench the autoinducer 2 (AI-2) signals secreted by E. coli K12. As a result, the initiation of quorum sensing for biofilm formation activated by AI-2 was restrained. The expressions of two biofilm-formation-related genes, motA and rcsB, were also suppressed. A dose of an AI-2 precursor, 4,5-dihydroxy-2,3-pentanedione, effectively restored the biofilm development. These results show that the photoexcited TiO2 could suppress biofilm formation through quenching AI-2 signals. This work may facilitate a better understanding about the ecological effects of increasingly released nanomaterials and provide implications for development of antifouling membranes.}, } @article {pmid27797183, year = {2016}, author = {Lee, HS and Dhar, BR and An, J and Rittmann, BE and Ryu, H and Santo Domingo, JW and Ren, H and Chae, J}, title = {The Roles of Biofilm Conductivity and Donor Substrate Kinetics in a Mixed-Culture Biofilm Anode.}, journal = {Environmental science & technology}, volume = {50}, number = {23}, pages = {12799-12807}, pmid = {27797183}, issn = {1520-5851}, support = {EPA999999/ImEPA/Intramural EPA/United States ; }, mesh = {Bioelectric Energy Sources ; *Biofilms ; *Electrodes ; Geobacter ; Kinetics ; }, abstract = {We experimentally assessed the kinetics and thermodynamics of electron transfer (ET) from the donor substrate (acetate) to the anode for a mixed-culture biofilm anode. We interpreted the results with a modified biofilm-conduction model consisting of three ET steps in series: (1) intracellular ET, (2) non-Ohmic extracellular ET (EET) from an outer membrane protein to an extracellular cofactor (EC), and (3) ET from the EC to the anode by Ohmic-conduction in the biofilm matrix. The steady-state current density was 0.82 ± 0.03 A/m[2] in a miniature microbial electrochemical cell operated at fixed anode potential of -0.15 V versus the standard hydrogen electrode. Illumina 16S-rDNA and -rRNA sequences showed that the Geobacter genus was less than 30% of the community of the biofilm anode. Biofilm conductivity was high at 2.44 ± 0.42 mS/cm, indicating that the maximum current density could be as high as 270 A/m[2] if only Ohmic-conduction EET was limiting. Due to the high biofilm conductivity, the maximum energy loss for Ohmic-conduction EET was negligible, 0.085 mV. The energy loss in the second ET step also was small, only 20 mV, and the potential for the EC involved in the second ET was -0.15 V, a value documenting that >99% of the EC was in the oxidized state. Monod kinetics for utilization of acetate were relatively slow, and at least 87% of the energy loss was in the intracellular step. Thus, intracellular ET was the main kinetic and thermodynamic bottleneck to ET from donor substrate to the anode for a highly conductive biofilm.}, } @article {pmid27796976, year = {2017}, author = {Wu, J and Zhang, Y}, title = {Evaluation of the impact of organic material on the anaerobic methane and ammonium removal in a membrane aerated biofilm reactor (MABR) based on the multispecies biofilm modeling.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {2}, pages = {1677-1685}, pmid = {27796976}, issn = {1614-7499}, mesh = {Ammonium Compounds/*isolation & purification ; Anaerobiosis ; Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification ; Kinetics ; Methane/*isolation & purification ; Models, Biological ; Sewage/analysis ; }, abstract = {The simultaneous nitrogen and methane removal by the combined nitritation, anaerobic ammonium oxidation (anammox), and nitrite dependent anaerobic methane oxidation (n-damo) processes in the membrane aerated biofilm reactor (MABR) offers clear advantages in term of energy saving and greenhouse gas emission mitigation. The rejected water from sludge digestion usually contained high ammonium, COD, and dissolved methane. The impact of influent COD on the anaerobic methane and ammonium removal in an MABR was evaluated in the model based study. The results indicated that the influent COD did not reduce the methane and ammonium removal efficiency at C/N ratio (influent COD/NH4[+]-N) less than 0.1. At high C/N ratio, the oxygen transfer coefficient needed to be increased to achieve high methane and nitrogen removal. Substrate flux analysis indicated that heterotrophic denitrification in the outside layer of biofilm reduced the impact of influent COD. Heterotrophic growth needed to be limited at the outside layer by using NO3[-] as electron acceptor; otherwise, the heterotrophic bacteria would compete NO2[-] and space with anammox and n-damo bacteria in the inner layers and reduce the nitrogen and methane removal efficiency.}, } @article {pmid27795383, year = {2017}, author = {Vila, T and Lopez-Ribot, JL}, title = {Screening the Pathogen Box for Identification of Candida albicans Biofilm Inhibitors.}, journal = {Antimicrobial agents and chemotherapy}, volume = {61}, number = {1}, pages = {}, pmid = {27795383}, issn = {1098-6596}, support = {R01 AI119554/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; }, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development/ultrastructure ; Cell Survival/drug effects ; Drug Combinations ; Drug Synergism ; Fluconazole/pharmacology ; Hep G2 Cells ; High-Throughput Screening Assays ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Plankton/drug effects/growth & development ; Small Molecule Libraries/*pharmacology ; }, abstract = {Candida albicans remains the main causative agent of candidiasis, one of the most frequent nosocomial infections, with unacceptably high mortality rates. Biofilm formation is a major risk factor for invasive candidiasis, as Candida biofilms display high-level resistance to most antifungal agents. In this work we have screened the Pathogen Box chemical library (Medicines for Malaria Venture [MMV], Switzerland) in search for inhibitors of C. albicans biofilm formation. Our initial screen identified seven hits, and additional dose-response assays confirmed the biofilm-inhibitory activity of six of these small molecules. Three compounds, MMV688768, MMV687273, and MMV687807, were also able to reduce the metabolic activity of cells within preformed biofilms. Interestingly, the most potent of these, compound MMV688768, displayed increased antibiofilm activity compared to its activity against planktonic cultures, indicating that it may affect processes with a predominant role during the biofilm mode of growth. This compound demonstrated a high selectivity index when its antibiofilm activity was compared with its toxicity in liver hepatocellular cells. In vitro combination assays showed a synergistic interaction between compound MMV688768 and fluconazole against preformed biofilms. Overall, our results indicate that this compound may constitute a potential candidate for further clinical development.}, } @article {pmid27736778, year = {2016}, author = {Gries, CM and Bruger, EL and Moormeier, DE and Scherr, TD and Waters, CM and Kielian, T}, title = {Cyclic di-AMP Released from Staphylococcus aureus Biofilm Induces a Macrophage Type I Interferon Response.}, journal = {Infection and immunity}, volume = {84}, number = {12}, pages = {3564-3574}, pmid = {27736778}, issn = {1098-5522}, support = {R01 GM109259/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cyclic AMP/*metabolism/*pharmacology ; Gene Expression Regulation ; Interferon Type I/genetics/*metabolism ; Macrophages/*drug effects ; Membrane Proteins/genetics/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Staphylococcus aureus/*physiology ; }, abstract = {Staphylococcus aureus is a leading cause of community- and nosocomial-acquired infections, with a propensity for biofilm formation. S. aureus biofilms actively skew the host immune response toward an anti-inflammatory state; however, the biofilm effector molecules and the mechanism(s) of action responsible for this phenomenon remain to be fully defined. The essential bacterial second messenger cyclic diadenylate monophosphate (c-di-AMP) is an emerging pathogen-associated molecular pattern during intracellular bacterial infections, as c-di-AMP secretion into the infected host cytosol induces a robust type I interferon (IFN) response. Type I IFNs have the potential to exacerbate infectious outcomes by promoting anti-inflammatory effects; however, the type I IFN response to S. aureus biofilms is unknown. Additionally, while several intracellular proteins function as c-di-AMP receptors in S. aureus, it has yet to be determined if any extracellular role for c-di-AMP exists and its release during biofilm formation has not yet been demonstrated. This study examined the possibility that c-di-AMP released during S. aureus biofilm growth polarizes macrophages toward an anti-inflammatory phenotype via type I interferon signaling. DacA, the enzyme responsible for c-di-AMP synthesis in S. aureus, was highly expressed during biofilm growth, and 30 to 50% of total c-di-AMP produced from S. aureus biofilm was released extracellularly due to autolytic activity. S. aureus biofilm c-di-AMP release induced macrophage type I IFN expression via a STING-dependent pathway and promoted S. aureus intracellular survival in macrophages. These findings identify c-di-AMP as another mechanism for how S. aureus biofilms promote macrophage anti-inflammatory activity, which likely contributes to biofilm persistence.}, } @article {pmid27793789, year = {2017}, author = {Guisbiers, G and Lara, HH and Mendoza-Cruz, R and Naranjo, G and Vincent, BA and Peralta, XG and Nash, KL}, title = {Inhibition of Candida albicans biofilm by pure selenium nanoparticles synthesized by pulsed laser ablation in liquids.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {13}, number = {3}, pages = {1095-1103}, pmid = {27793789}, issn = {1549-9642}, support = {G12 MD007591/MD/NIMHD NIH HHS/United States ; R25 GM060655/GM/NIGMS NIH HHS/United States ; T34 GM007717/GM/NIGMS NIH HHS/United States ; }, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candidiasis/*prevention & control ; Humans ; Lasers ; Nanoparticles/*chemistry/ultrastructure ; Nanotechnology/instrumentation/*methods ; Selenium/chemistry/*pharmacology ; }, abstract = {Selenoproteins play an important role in the human body by accomplishing essential biological functions like oxido-reductions, antioxidant defense, thyroid hormone metabolism and immune response; therefore, the possibility to synthesize selenium nanoparticles free of any contaminants is exciting for future nano-medical applications. This paper reports the first synthesis of selenium nanoparticles by femtosecond pulsed laser ablation in de-ionized water. Those pure nanoparticles have been successfully used to inhibit the formation of Candida albicans biofilms. Advanced electron microscopy images showed that selenium nanoparticles easily adhere on the biofilm, then penetrate into the pathogen, and consequently damage the cell structure by substituting with sulfur. 50% inhibition of Candida albicans biofilm was obtained at only 25 ppm. Finally, the two physical parameters proved to affect strongly the viability of Candida albicans are the crystallinity and particle size.}, } @article {pmid27793690, year = {2016}, author = {Sasikala, D and Srinivasan, P}, title = {Characterization of potential lytic bacteriophage against Vibrio alginolyticus and its therapeutic implications on biofilm dispersal.}, journal = {Microbial pathogenesis}, volume = {101}, number = {}, pages = {24-35}, doi = {10.1016/j.micpath.2016.10.017}, pmid = {27793690}, issn = {1096-1208}, mesh = {Bacteriophages/*classification/growth & development/*isolation & purification/ultrastructure ; Biofilms/*growth & development ; Foodborne Diseases/microbiology/therapy ; Host Specificity ; Humans ; Microscopy, Electron, Transmission ; Myoviridae/*classification/growth & development/*isolation & purification/ultrastructure ; Phage Therapy/methods ; Seafood/microbiology ; Vibrio Infections/microbiology/therapy ; Vibrio alginolyticus/physiology/*virology ; Virion/ultrastructure ; }, abstract = {Vibrio alginolyticus is a leading cause of vibriosis, presenting opportunistic infections to humans associated with raw seafood contamination. At present, phage therapy that acts as an alternative sanitizing agent is explored for targeting V. alginolyticus. The study outcome revealed that the phage VP01 with its extreme lytic effect showed a high potential impact on the growth of V. alginolyticus as well as biofilm formation. Electron microscopy revealed the phage resemblance to Myoviridae, based on its morphology. Further study clarified that the phage VP01 possesses a broad host spectrum and amazing phage sensitivity at different pH, high thermal stability, and high burst size of 415 PFU/cell. In addition, the investigation of phage co-culturing against this pathogen resulted in a significant growth reduction even at less MOIs 0.1 and 1. These results suggest that the phage could be a promising candidate for the control of V. alginolyticus infections.}, } @article {pmid27793096, year = {2016}, author = {Melo, TA and Dos Santos, TF and de Almeida, ME and Junior, LA and Andrade, EF and Rezende, RP and Marques, LM and Romano, CC}, title = {Inhibition of Staphylococcus aureus biofilm by Lactobacillus isolated from fine cocoa.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {250}, pmid = {27793096}, issn = {1471-2180}, mesh = {Antibiosis ; Biofilms/*growth & development ; Chocolate/*microbiology ; Culture Media ; Fermentation ; Lactobacillus/isolation & purification/*physiology ; Limosilactobacillus fermentum/physiology ; Lactobacillus plantarum/physiology ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Phenotype ; Polystyrenes ; Probiotics ; Staphylococcus aureus/*physiology ; }, abstract = {BACKGROUND: Biofilm production represents an important virulence and pathogenesis factor for Staphylococcus aureus. The formation of biofilms on medical devices is a major concern in hospital environments, as they can become a constant source of infection. Probiotic bacteria, such as Lactobacillus fermentum and L. plantarum, have been found to inhibit biofilm formation; however little is known about the underlying mechanism. In this study, we tested the activity of supernatants produced by L. fermentum TCUESC01 and L. plantarum TCUESC02, isolated during the fermentation of fine cocoa, against S. aureus CCMB262 biofilm production. We measured inhibition of biofilm formation in vitro and analyzed biofilm structure by confocal and electronic microscopy. Additionally, we quantified the expression of S. aureus genes icaA and icaR involved in the synthesis of the biofilm matrix by real-time PCR.

RESULTS: Both Lactobacillus supernatants inhibited S. aureus growth. However, only L. fermentum TCUESC01 significantly reduced the thickness of the biofilm, from 14 μm to 2.83 μm (at 18 mg∙mL[-1], 90 % of the minimum inhibitory concentration, MIC), 3.12 μm (at 14 mg∙mL[-1], 70 % of the MIC), and 5.21 μm (at 10 mg∙mL[-1], 50 % of the MIC). Additionally, L. fermentum TCUESC01 supernatant modulated the expression of icaA and icaR.

CONCLUSIONS: L. fermentum TCUESC01 reduces the formation of S. aureus biofilm under subinhibitory conditions. Inhibition of biofilm production probably depends on modulation of the ica operon.}, } @article {pmid27792789, year = {2016}, author = {Valentini, M and Laventie, BJ and Moscoso, J and Jenal, U and Filloux, A}, title = {The Diguanylate Cyclase HsbD Intersects with the HptB Regulatory Cascade to Control Pseudomonas aeruginosa Biofilm and Motility.}, journal = {PLoS genetics}, volume = {12}, number = {10}, pages = {e1006354}, pmid = {27792789}, issn = {1553-7404}, support = {MR/J006874/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Biofilms/growth & development ; Cell Cycle/genetics ; Cell Division/genetics ; Cell Movement/*genetics ; Cyclic GMP/genetics ; Escherichia coli Proteins/*genetics/metabolism ; Flagella/genetics ; Gene Expression Regulation, Bacterial ; Phosphorus-Oxygen Lyases/*genetics/metabolism ; Phosphorylation ; Pseudomonas aeruginosa/*genetics/pathogenicity ; }, abstract = {The molecular basis of second messenger signaling relies on an array of proteins that synthesize, degrade or bind the molecule to produce coherent functional outputs. Cyclic di-GMP (c-di-GMP) has emerged as a eubacterial nucleotide second messenger regulating a plethora of key behaviors, like the transition from planktonic cells to biofilm communities. The striking multiplicity of c-di-GMP control modules and regulated cellular functions raised the question of signaling specificity. Are c-di-GMP signaling routes exclusively dependent on a central hub or can they be locally administrated? In this study, we show an example of how c-di-GMP signaling gains output specificity in Pseudomonas aeruginosa. We observed the occurrence in P. aeruginosa of a c-di-GMP synthase gene, hsbD, in the proximity of the hptB and flagellar genes cluster. We show that the HptB pathway controls biofilm formation and motility by involving both HsbD and the anti-anti-sigma factor HsbA. The rewiring of c-di-GMP signaling into the HptB cascade relies on the original interaction between HsbD and HsbA and on the control of HsbD dynamic localization at the cell poles.}, } @article {pmid27792773, year = {2016}, author = {Karna, SL and D'Arpa, P and Chen, T and Qian, LW and Fourcaudot, AB and Yamane, K and Chen, P and Abercrombie, JJ and You, T and Leung, KP}, title = {RNA-Seq Transcriptomic Responses of Full-Thickness Dermal Excision Wounds to Pseudomonas aeruginosa Acute and Biofilm Infection.}, journal = {PloS one}, volume = {11}, number = {10}, pages = {e0165312}, pmid = {27792773}, issn = {1932-6203}, mesh = {Animals ; *Biofilms ; Female ; Gene Expression Regulation/physiology ; Pseudomonas Infections/*physiopathology ; *Pseudomonas aeruginosa ; RNA/genetics/physiology ; Rabbits ; Skin Diseases, Bacterial/microbiology/*physiopathology ; Transcriptome/*physiology ; Wounds and Injuries/*microbiology/physiopathology ; }, abstract = {Pseudomonas aeruginosa infections of wounds in clinical settings are major complications whose outcomes are influenced by host responses that are not completely understood. Herein we evaluated transcriptomic changes of wounds as they counter P. aeruginosa infection-first active infection, and then chronic biofilm infection. We used the dermal full-thickness, rabbit ear excisional wound model. We studied the wound response: towards acute infection at 2, 6, and 24 hrs after inoculating 106 bacteria into day-3 wounds; and, towards more chronic biofilm infection of wounds similarly infected for 24 hrs but then treated with topical antibiotic to coerce biofilm growth and evaluated at day 5 and 9 post-infection. The wounds were analyzed for bacterial counts, expression of P. aeruginosa virulence and biofilm-synthesis genes, biofilm morphology, infiltrating immune cells, re-epithelialization, and genome-wide gene expression (RNA-Seq transcriptome). This analysis revealed that 2 hrs after bacterial inoculation into day-3 wounds, the down-regulated genes (infected vs. non-infected) of the wound edge were nearly all non-coding RNAs (ncRNAs), comprised of snoRNA, miRNA, and RNU6 pseudogenes, and their down-regulation preceded a general down-regulation of skin-enriched coding gene expression. As the active infection intensified, ncRNAs remained overrepresented among down-regulated genes; however, at 6 and 24 hrs they changed to a different set, which overlapped between these times, and excluded RNU6 pseudogenes but included snRNA components of the major and minor spliceosomes. Additionally, the raw counts of multiple types of differentially-expressed ncRNAs increased on post-wounding day 3 in control wounds, but infection suppressed this increase. After 5 and 9 days, these ncRNA counts in control wounds decreased, whereas they increased in the infected, healing-impaired wounds. These data suggest a sequential and coordinated change in the levels of transcripts of multiple major classes of ncRNAs in wound cells transitioning from inflammation to the proliferation phase of healing.}, } @article {pmid27791154, year = {2016}, author = {Ashbaugh, AG and Jiang, X and Zheng, J and Tsai, AS and Kim, WS and Thompson, JM and Miller, RJ and Shahbazian, JH and Wang, Y and Dillen, CA and Ordonez, AA and Chang, YS and Jain, SK and Jones, LC and Sterling, RS and Mao, HQ and Miller, LS}, title = {Polymeric nanofiber coating with tunable combinatorial antibiotic delivery prevents biofilm-associated infection in vivo.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {45}, pages = {E6919-E6928}, pmid = {27791154}, issn = {1091-6490}, support = {R01 EB020539/EB/NIBIB NIH HHS/United States ; UL1 TR001079/TR/NCATS NIH HHS/United States ; }, abstract = {Bacterial biofilm formation is a major complication of implantable medical devices that results in therapeutically challenging chronic infections, especially in cases involving antibiotic-resistant bacteria. As an approach to prevent these infections, an electrospun composite coating comprised of poly(lactic-coglycolic acid) (PLGA) nanofibers embedded in a poly(ε-caprolactone) (PCL) film was developed to locally codeliver combinatorial antibiotics from the implant surface. The release of each antibiotic could be adjusted by loading each drug into the different polymers or by varying PLGA:PCL polymer ratios. In a mouse model of biofilm-associated orthopedic-implant infection, three different combinations of antibiotic-loaded coatings were highly effective in preventing infection of the bone/joint tissue and implant biofilm formation and were biocompatible with enhanced osseointegration. This nanofiber composite-coating technology could be used to tailor the delivery of combinatorial antimicrobial agents from various metallic implantable devices or prostheses to effectively decrease biofilm-associated infections in patients.}, } @article {pmid27790837, year = {2017}, author = {Tremblay, YDN and Labrie, J and Chénier, S and Jacques, M}, title = {Actinobacillus pleuropneumoniae grows as aggregates in the lung of pigs: is it time to refine our in vitro biofilm assays?.}, journal = {Microbial biotechnology}, volume = {10}, number = {4}, pages = {756-760}, pmid = {27790837}, issn = {1751-7915}, mesh = {Actinobacillus Infections/microbiology/pathology/*veterinary ; Actinobacillus pleuropneumoniae/growth & development/*physiology ; Animals ; *Bacterial Adhesion ; Bacteriological Techniques ; Biofilms/*growth & development ; In Situ Hybridization, Fluorescence ; Lung/*microbiology/pathology ; Microscopy, Confocal ; Pleuropneumonia/microbiology/pathology/*veterinary ; Swine ; Swine Diseases/*microbiology/pathology ; }, abstract = {Actinobacillus pleuropneumoniae causes porcine pleuropneumonia and forms biofilms in vitro on abiotic surfaces; however, presence of biofilms during infections has not been documented. The aim of this study was to use a species-specific fluorescent oligonucleotide probe and confocal microscopy to localize A. pleuropneumoniae in the lungs of two naturally infected pigs. Actinobacillus pleuropneumoniae was detected by fluorescence in situ hybridization and observed to grow as aggregates (~30-45 μm) during a natural infection. As the A. pleuropneumoniae aggregates observed in porcine lungs differed from the biofilms grown on a solid surface obtained in vitro, we designed a new biofilm assay using agarose, a porous substrate, favouring the formation of aggregates. In this study, we described for the first time the mode of growth of A. pleuropneumoniae during a natural infection in pigs. We also propose an in vitro biofilm assay for A. pleuropneumoniae using a porous substrate which allows the formation of aggregates. This assay might be more representative of the in vivo situation, at least in terms of the size of the bacterial aggregates and the presence of a porous matrix, and could potentially be used to test the susceptibility of A. pleuropneumoniae aggregates to antibiotics and disinfectants.}, } @article {pmid27790262, year = {2016}, author = {Zand, V and Lotfi, M and Soroush, MH and Abdollahi, AA and Sadeghi, M and Mojadadi, A}, title = {Antibacterial Efficacy of Different Concentrations of Sodium Hypochlorite Gel and Solution on Enterococcus faecalis Biofilm.}, journal = {Iranian endodontic journal}, volume = {11}, number = {4}, pages = {315-319}, pmid = {27790262}, issn = {1735-7497}, abstract = {INTRODUCTION: This in vitro study compared the antibacterial efficacy of 2.5% sodium hypochlorite gel and 2.5% and 5.25% sodium hypochlorite solutions on Enterococcus faecalis (E. faecalis) biofilm.

METHODS AND MATERIALS: The root canals of 60 extracted human single-rooted teeth were contaminated with E. faecalis and incubated for 6 weeks. The samples were randomly assigned to three experimental groups and one control group (n=15). The study protocol in the experimental groups consisted of injection of 5 mL of each irrigant into the root canals. Samples were collected from the root canal walls and 1:10 serial dilutions were prepared and added to Muller Hinton Agar (MHA) plates and incubated at 37[°]C for 48 h. A classic colony counting technique was used for determining vital E. faecalis bacterial counts in MHA plates. The Kruskal-Wallis test was used for statistical analysis of the data. The level of significance was set at 0.05.

RESULTS: The antibacterial effect of the irrigants in all three experimental groups was significantly greater than the control group (P<0.05), with no significant difference between 2.5% and 5.25% NaOCl solutions (P>0.05). The effect of 2.5% and 5.25% NaOCl solutions were significantly superior to 2.5% NaOCl gel (P<0.05).

CONCLUSION: Under the limitations of this study, 2.5% NaOCl gel was effective in reducing E. faecalis counts; however this effect was less than that of NaOCl solutions.}, } @article {pmid27790260, year = {2016}, author = {Ramezanali, F and Samimi, S and Kharazifard, M and Afkhami, F}, title = {The in Vitro Antibacterial Efficacy of Persian Green Tea Extract as an Intracanal Irrigant on Enterococcus faecalis Biofilm.}, journal = {Iranian endodontic journal}, volume = {11}, number = {4}, pages = {304-308}, pmid = {27790260}, issn = {1735-7497}, abstract = {INTRODUCTION: The aim of this study was to compare the antibacterial effect of Persian green tea extract (GTE) and 2.5% sodium hypochlorite (NaOCl) against Enterococcus faecalis (E. faecalis) as an intracanal irrigant.

METHODS AND MATERIALS: Thirty freshly extracted teeth were instrumented and sectioned into mesial and distal segments. The specimens were put into wells containing 2 mL of E. faecalis-containing medium. After 3 weeks, the specimens were removed and divided randomly into three groups (n=20). Each group was exposed to 3 mL of different irrigants for 3 min. Groups 1, 2 and 3 were irrigated with GTE, 2.5% NaOCl and normal saline, respectively. Biofilm formed in the middle third of the root canal was carved by sterile scalpel and cultured in Mueller-Hinton medium. Number of colony forming units (CFU) was counted on each plate. In addition, antimicrobial activity of the irrigants was evaluated by the agar disc diffusion test. The diameter of inhibition zone (IZ) around each irrigant was evaluated. The Kruskal-Wallis and Dunn tests were used to analysis the data.

RESULTS: While in NaOCl group no bacterial colonies were observed, the mean number of E. faecalis in GTE and control groups were 275±74 CFU/mL (P<0.001) and 119×10[8]±11×10[8] (P<0.001), respectively. The mean of IZ in NaOCl and GTE groups were 24.35±0.78 and 6.9±0.87 mm, in order of appearance (P<0.001). Zone of inhibition was not observed around the control group (P<0.001).

CONCLUSION: This research highlighted the potential role of plant extracts in antimicrobial root canal irrigation protocol.}, } @article {pmid27790205, year = {2016}, author = {Vozza, NF and Abdian, PL and Russo, DM and Mongiardini, EJ and Lodeiro, AR and Molin, S and Zorreguieta, A}, title = {A Rhizobium leguminosarum CHDL- (Cadherin-Like-) Lectin Participates in Assembly and Remodeling of the Biofilm Matrix.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1608}, pmid = {27790205}, issn = {1664-302X}, abstract = {In natural environments most bacteria live in multicellular structures called biofilms. These cell aggregates are enclosed in a self-produced polymeric extracellular matrix, which protects the cells, provides mechanical stability and mediates cellular cohesion and adhesion to surfaces. Although important advances were made in the identification of the genetic and extracellular factors required for biofilm formation, the mechanisms leading to biofilm matrix assembly, and the roles of extracellular proteins in these processes are still poorly understood. The symbiont Rhizobium leguminosarum requires the synthesis of the acidic exopolysaccharide and the PrsDE secretion system to develop a mature biofilm. PrsDE is responsible for the secretion of the Rap family of proteins that share one or two Ra/CHDL (cadherin-like-) domains. RapA2 is a calcium-dependent lectin with a cadherin-like β sheet structure that specifically recognizes the exopolysaccharide, either as a capsular polysaccharide (CPS) or in its released form [extracellular polysaccharide (EPS)]. In this study, using gain and loss of function approaches combined with phenotypic and microscopic studies we demonstrated that RapA lectins are involved in biofilm matrix development and cellular cohesion. While the absence of any RapA protein increased the compactness of bacterial aggregates, high levels of RapA1 expanded distances between cells and favored the production of a dense matrix network. Whereas endogenous RapA(s) are predominantly located at one bacterial pole, we found that under overproduction conditions, RapA1 surrounded the cell in a way that was reminiscent of the capsule. Accordingly, polysaccharide analyses showed that the RapA lectins promote CPS formation at the expense of lower EPS production. Besides, polysaccharide analysis suggests that RapA modulates the EPS size profile. Collectively, these results show that the interaction of RapA lectins with the polysaccharide is involved in rhizobial biofilm matrix assembly and remodeling.}, } @article {pmid27759365, year = {2016}, author = {Wonoputri, V and Gunawan, C and Liu, S and Barraud, N and Yee, LH and Lim, M and Amal, R}, title = {Iron Complex Facilitated Copper Redox Cycling for Nitric Oxide Generation as Nontoxic Nitrifying Biofilm Inhibitor.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {44}, pages = {30502-30510}, doi = {10.1021/acsami.6b10357}, pmid = {27759365}, issn = {1944-8252}, mesh = {Biofilms ; Copper ; Iron/*chemistry ; Nitric Oxide ; Oxidation-Reduction ; }, abstract = {In this study, we developed poly(vinyl chloride) (PVC)-solvent casted mixed metal copper and iron complexes capable of catalytic generation of the antibiofilm nitric oxide (NO) from endogenous nitrite. In the absence of additional reducing agent, we demonstrated that the presence of iron complex facilitates a redox cycling, converting the copper(II) complex to active copper(I) species, which catalyzes the generation of NO from nitrite. Assessed by protein assay and surface coverage analyses, the presence of the mixed metal complexes in systems containing water industry-relevant nitrite-producing nitrifying biofilms was shown to result in a "nontoxic mode" of biofilm suppression, while confining the bacterial growth to the free-floating planktonic phase. Addition of an NO scavenger into the mixed metal system eliminated the antibiofilm effects, therefore validating first, the capability of the mixed metal complexes to catalytically generate NO from the endogenously produced nitrite and second, the antibiofilm effects of the generated NO. The work highlights the development of self-sustained antibiofilm materials that features potential for industrial applications. The novel NO-generating antibiofilm technology diverts from the unfavorable requirement of adding a reducing agent and importantly, the less tendency for development of bacterial resistance.}, } @article {pmid27742478, year = {2016}, author = {Takenaka, S and Oda, M and Domon, H and Ohsumi, T and Suzuki, Y and Ohshima, H and Yamamoto, H and Terao, Y and Noiri, Y}, title = {Vizantin inhibits bacterial adhesion without affecting bacterial growth and causes Streptococcus mutans biofilm to detach by altering its internal architecture.}, journal = {Biochemical and biophysical research communications}, volume = {480}, number = {2}, pages = {173-179}, doi = {10.1016/j.bbrc.2016.10.021}, pmid = {27742478}, issn = {1090-2104}, mesh = {Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Gene Expression Regulation, Bacterial/drug effects ; Glycolipids/chemistry/*pharmacology ; Streptococcus mutans/*drug effects/growth & development/physiology ; Sulfates/chemistry ; Trehalose/*analogs & derivatives/chemistry/pharmacology ; }, abstract = {An ideal antibiofilm strategy is to control both in the quality and quantity of biofilm while maintaining the benefits derived from resident microflora. Vizantin, a recently developed immunostimulating compound, has also been found to have antibiofilm property. This study evaluated the influence on biofilm formation of Streptococcus mutans in the presence of sulfated vizantin and biofilm development following bacterial adhesion on a hydroxyapatite disc coated with sulfated vizantin. Supplementation with sulfated vizantin up to 50 μM did not affect either bacterial growth or biofilm formation, whereas 50 μM sulfated vizantin caused the biofilm to readily detach from the surface. Sulfated vizantin at the concentration of 50 μM upregulated the expression of the gtfB and gtfC genes, but downregulated the expression of the gtfD gene, suggesting altered architecture in the biofilm. Biofilm development on the surface coated with sulfated vizantin was inhibited depending on the concentration, suggesting prevention from bacterial adhesion. Among eight genes related to bacterial adherence in S. mutans, expression of gtfB and gtfC was significantly upregulated, whereas the expression of gtfD, GbpA and GbpC was downregulated according to the concentration of vizantin, especially with 50 μM vizantin by 0.8-, 0.4-, and 0.4-fold, respectively. These findings suggest that sulfated vizantin may cause structural degradation as a result of changing gene regulation related to bacterial adhesion and glucan production of S. mutans.}, } @article {pmid27741475, year = {2016}, author = {Huang, Y and Xiong, W and Liao, Q and Fu, Q and Xia, A and Zhu, X and Sun, Y}, title = {Comparison of Chlorella vulgaris biomass productivity cultivated in biofilm and suspension from the aspect of light transmission and microalgae affinity to carbon dioxide.}, journal = {Bioresource technology}, volume = {222}, number = {}, pages = {367-373}, doi = {10.1016/j.biortech.2016.09.099}, pmid = {27741475}, issn = {1873-2976}, mesh = {Biofilms ; Biomass ; Carbon Dioxide/metabolism ; Cell Culture Techniques/*methods ; Chlorella vulgaris/cytology/*growth & development/*metabolism ; Light ; Microalgae/cytology/growth & development/*metabolism ; Suspensions ; }, abstract = {To investigate light transmission and cells affinity to CO2, Chlorellavulgaris was attached to microfiltration membrane that laid on the solidified BG11 medium compared to that in suspended cultivation mode in this study. The results showed that C. vulgaris showed a 30.4% higher biomass production (103gm[-2]) in attached than in suspend system. The upper layer of biofilm with a thickness of 41.31μm (the corresponding areal density of 40gm[-2]) was effectively illuminated under light intensity of 120μmolm[-2]s[-1] and more than 40% of the microalgal cells were in light even the areal density was high to 100gm[-2]. While only 2.5% of the cells were effectively illuminated in the suspended cultivation system. Furthermore, microalgae cells in biofilm showed a higher affinity to CO2 compared with that in suspension, and CO2 saturation point of microalgae cells in biofilm was 1.5% but 4.5% in suspension.}, } @article {pmid27716565, year = {2016}, author = {Zheng, D and Chang, Q and Li, Z and Gao, M and She, Z and Wang, X and Guo, L and Zhao, Y and Jin, C and Gao, F}, title = {Performance and microbial community of a sequencing batch biofilm reactor treating synthetic mariculture wastewater under long-term exposure to norfloxacin.}, journal = {Bioresource technology}, volume = {222}, number = {}, pages = {139-147}, doi = {10.1016/j.biortech.2016.09.114}, pmid = {27716565}, issn = {1873-2976}, mesh = {Aquaculture/*methods ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; High-Throughput Nucleotide Sequencing ; Microbial Consortia/*drug effects/genetics ; Nitrates/metabolism ; Nitrification ; Norfloxacin/*pharmacology ; Waste Disposal, Fluid/instrumentation/*methods ; Wastewater ; }, abstract = {The performance and microbial community of a sequencing batch biofilm reactor (SBBR) treating synthetic mariculture wastewater were evaluated under long-term exposure to norfloxacin (NFX) due to the overuse of antibiotics during the mariculture. The COD and NH4[+]-N removals had no distinct change at 0-6mgL[-1] NFX and were inhibited at 6-35mgL[-1] NFX. The specific oxygen uptake rate (SOUR), specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR) and specific nitrate reduction rate (SNRR) of the biofilm kept a decreasing tendency with the increase of NFX concentration from 0 to 35mgL[-1]. The presence of NFX promoted the microorganisms to secrete more extracellular polymeric substances (EPS) and affected the chemical compositions of EPS. The microbial richness and diversity showed some obvious variations at different NFX concentrations. The present results demonstrated that NFX inhibited the SBBR performance and should decrease the NFX dosage in the mariculture.}, } @article {pmid27652612, year = {2016}, author = {Kaistha, SD and Umrao, PD}, title = {Bacteriophage for Mitigation of Multiple Drug Resistant Biofilm Forming Pathogens.}, journal = {Recent patents on biotechnology}, volume = {10}, number = {2}, pages = {184-194}, doi = {10.2174/1872208310666160919122155}, pmid = {27652612}, issn = {2212-4012}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteriophages/*physiology ; Biofilms/*drug effects ; Drug Resistance, Microbial/*drug effects ; Drug Resistance, Multiple/*drug effects ; Humans ; Patents as Topic ; Quorum Sensing/drug effects ; }, abstract = {BACKGROUND: Microbial communities encased in exopolymeric substances (EPS) attached to suitable substrate as biofilms show heightened resistance to multiple drugs including antibiotics. One promising control strategy in dealing with the ever mounting problem of antibiotic resistance amongst biofilm forming bacterial pathogens is the use of biological agents.

OBJECTIVE: This review focuses on the development of bacteriophages as means of disrupting biofilm forming pathogens and hence mitigation of multiple drug resistant organisms.

RESULTS: Bacteriophages are obligatory viral intracellular parasites that can cause lytic infection of their bacterial hosts. Bacteriophage (Phage) therapy is advantageous in being highly host specific, safe and non-toxic to humans and hence environmental friendly. Bacteriophage induced lysis of cells within the biofilm is aided by the production of penetrating enzymes such as endolysins and EPS depolymerases as well quorum sensing inhibitors such as lactonases.

CONCLUSION: Phages are a promising alternative therapy for the control of multiple drug resistant (MDR) pathogens. Several phage (indigenous and engineered)/ phage products are currently being patented and developed as commercial biological control agents.}, } @article {pmid27638940, year = {2016}, author = {Sengupta, C and Mukherjee, O and Chowdhury, R}, title = {Adherence to Intestinal Cells Promotes Biofilm Formation in Vibrio cholerae.}, journal = {The Journal of infectious diseases}, volume = {214}, number = {10}, pages = {1571-1578}, doi = {10.1093/infdis/jiw435}, pmid = {27638940}, issn = {1537-6613}, mesh = {Animals ; *Bacterial Adhesion ; Biofilms/*growth & development ; Cell Line ; Epithelial Cells/*microbiology ; Gene Expression Profiling ; Genes, Bacterial ; Humans ; Ileum/microbiology ; Rabbits ; Time Factors ; Vibrio cholerae O1/*physiology ; }, abstract = {Vibrio cholerae, the etiological agent of cholera, is known to form biofilms to persist in the environment. It is demonstrated here that even during infection, biofilm genes are upregulated, and microscopic observation indicated that biofilm formation is initiated almost immediately after adherence of V. cholerae to intestinal cells. About 7-fold upregulation of the biofilm regulatory gene vpsT was observed within 30 minutes of adherence of V. cholerae to the intestinal cell line INT 407, and a massive induction of about 700-fold was observed in rabbit ileal loops. The upregulation was observed in the classical and El Tor biotype strains of serogroup O1 that is most frequently associated with epidemic cholera. vpsT upregulation was primarily dependent on the virulence master regulator AphA. Of possible clinical relevance was the observation that V. cholerae in the INT 407-associated biofilms was significantly more resistant to antibiotics than unadhered planktonic cells.}, } @article {pmid27788469, year = {2017}, author = {Kumari, S and Mangwani, N and Das, S}, title = {Interaction of Pb(II) and biofilm associated extracellular polymeric substances of a marine bacterium Pseudomonas pseudoalcaligenes NP103.}, journal = {Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy}, volume = {173}, number = {}, pages = {655-665}, doi = {10.1016/j.saa.2016.10.009}, pmid = {27788469}, issn = {1873-3557}, mesh = {Biofilms/drug effects/*growth & development ; Lead/chemistry/*metabolism/pharmacology ; Magnetic Resonance Spectroscopy ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/chemistry/isolation & purification/*metabolism ; Pseudomonas pseudoalcaligenes/chemistry/genetics/*physiology ; Seawater/microbiology ; Spectrometry, Fluorescence ; Spectrometry, X-Ray Emission ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction ; }, abstract = {Three-dimensional excitation-emission matrix (3D EEM) fluorescence spectroscopy and attenuated total reflectance fourier-transformed infrared spectroscopy (ATR-FTIR) was used to evaluate the interaction of biofilm associated extracellular polymeric substances (EPS) of a marine bacterium Pseudomonas pseudoalcaligenes NP103 with lead [Pb(II)]. EEM fluorescence spectroscopic analysis revealed the presence of one protein-like fluorophore in the EPS of P. pseudoalcaligenes NP103. Stern-Volmer equation indicated the existence of only one binding site (n=0.789) in the EPS of P. pseudoalcaligenes NP103. The interaction of Pb(II) with EPS was spontaneous at room temperature (∆G=-2.78kJ/K/mol) having binding constant (Kb) of 2.59M[-1]. ATR-FTIR analysis asserted the involvement of various functional groups such as sulphydryl, phosphate and hydroxyl and amide groups of protein in Pb(II) binding. Scanning electron microscopy (SEM) and fluorescence microscopy analysis displayed reduced growth of biofilm with altered surface topology in Pb(II) supplemented medium. Energy dispersive X-ray spectroscopy (EDX) analysis revealed the entrapment of Pb in the EPS. Uronic acid, a characteristic functional group of biofilm, was observed in [1]H NMR spectroscopy. The findings suggest that biofilm associated EPS are perfect organic ligands for Pb(II) complexation and may significantly augment the bioavailability of Pb(II) in the metal contaminated environment for subsequent sequestration.}, } @article {pmid27784787, year = {2016}, author = {Stenvang, M and Dueholm, MS and Vad, BS and Seviour, T and Zeng, G and Geifman-Shochat, S and Søndergaard, MT and Christiansen, G and Meyer, RL and Kjelleberg, S and Nielsen, PH and Otzen, DE}, title = {Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {51}, pages = {26540-26553}, pmid = {27784787}, issn = {1083-351X}, mesh = {Amyloid/*biosynthesis ; Bacterial Proteins/*biosynthesis ; Benzothiazoles ; Biofilms/*drug effects/growth & development ; Catechin/*analogs & derivatives/pharmacology ; Drug Resistance, Bacterial/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Pseudomonas Infections/drug therapy/metabolism ; Pseudomonas aeruginosa/*physiology ; Thiazoles/pharmacology ; Tobramycin/*pharmacology ; }, abstract = {Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.}, } @article {pmid27784450, year = {2016}, author = {Wang, X and Zhou, YC and Huang, YC and Zou, TN and Lü, ZY and Chen, Y and Liu, X and Duan, WS}, title = {[Estradiol stimulates the growth and biofilm formation of clinical Staphylococcus epidermidis].}, journal = {Zhonghua yi xue za zhi}, volume = {96}, number = {38}, pages = {3083-3089}, doi = {10.3760/cma.j.issn.0376-2491.2016.38.010}, pmid = {27784450}, issn = {0376-2491}, mesh = {*Biofilms ; Estradiol ; Microscopy, Confocal ; *Staphylococcus epidermidis ; }, abstract = {Objective: To investigate the effect of steroid hormones on the growth and biofilm formation of S. epidermidis. Methods: In all experiments, two S. epidermidis standard strains (ATCC12228 and ATCC35984) and two S. epidermidis clinical strains (SE101 and SE40) were incubated on the surface of silica gel in estradiol concentrations of 0, 50, 125, 250 and 500 pmol/L at 4, 6, 12, 24, 48 and 72 hours. Growth curve were drawn by means of the OD value. Formed biofilms were assessed by crystal violet staining methods. In order to observe the processes and structures of biofilm, the confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM) were used. Results: All of the four strains which were incubated with the concentrations of 125 pmol/L of estradiol had entered the logarithmic growth stage ahead of the blank control (3 h and 4 h). Crystal violet staining indicated that there was no biofilm for ATCC12228. Improved primary attachment abilities were found for ATCC35984 and SE101 in the presence of estradiol, and the OD values were 0 pmol/L (0.081±0.015 and 0.082±0.011), 50 pmol /L (0.087±0.013 and 0.088±0.010), 125 pmol/L (0.175±0.052 and 0.091±0.012), 250 pmol/L (0.153±0.036 and 0.090±0.006), 500 pmol/L (0.157±0.050 and 0.082±0.032), respectively. The thickness of biofilm reached the peak in 125 pmol/L estradiol at 24 h. CLSM and SEM found estradiol promoted the biofilm maturity and the biofilm of 125 pmol/L group was denser and thicker than that of the other concentration groups. Conclusions: Our in vitro experiments indicate that estradiol could promote the growth of S. epidermidis which exit on the surface of silica gel, and improve the ability of biofilm formation of S. epidermidis.}, } @article {pmid27725283, year = {2016}, author = {Muslim, SN and Al-Kadmy, IMS and Hussein, NH and Mohammed Ali, AN and Taha, BM and Aziz, SN and Kheraif, AAA and Divakar, DD and Ramakrishnaiah, R}, title = {Chitosanase purified from bacterial isolate Bacillus licheniformis of ruined vegetables displays broad spectrum biofilm inhibition.}, journal = {Microbial pathogenesis}, volume = {100}, number = {}, pages = {257-262}, doi = {10.1016/j.micpath.2016.10.001}, pmid = {27725283}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/isolation & purification/*metabolism ; Bacillus licheniformis/*enzymology/growth & development/isolation & purification/metabolism ; Biofilms/*drug effects ; Chitosan/metabolism ; Glycoside Hydrolases/isolation & purification/*metabolism ; Vegetables/*microbiology ; }, abstract = {A number of bacterial species produces chitosanases which has variety of applications because of its high biodegradability, non-toxicity and antimicrobial assets. In the present study chitosanase is purified from new bacterial species Bacillus licheniformis from spoiled vegetable. This novel strain of Bacillus licheniformis isolated from spoilt cucumber and pepper samples has the ability to produce the chitosanase enzyme when grown on chitosan substrate. Study also examined its antibiofilm properties against diverse bacterial species with biofilm forming ability. The purified chitosanase inhibited the biofilm formation ability for all Gram-negative and Gram-positive biofilm-forming bacteria [biofilm producers] tested in this study in congo red agar and microtiter plate's methods. Highly antibiofilm activity of chitosanase was recorded against Pseudomonas aeruginosa followed by Klebsiella pneumoniae with reduction of biofilm formation upto 22 and 29%, respectively compared with [100] % of control. Biofilm formation has multiple role including ability to enhance resistance and self-protection from external stress. This chitosanase has promising benefit as antibiofilm agent against biofilm forming pathogenic bacteria and has promising application as alternative antibiofilm agents to combat the growing number of multidrug resistant pathogen-associated infections, especially in situation where biofilms are involved.}, } @article {pmid27725281, year = {2016}, author = {Pedroso, SHSP and Sandes, SHC and Luiz, KCM and Dias, RS and Filho, RAT and Serufo, JC and Farias, LM and Carvalho, MAR and Bomfim, MRQ and Santos, SG}, title = {Biofilm and toxin profile: A phenotypic and genotypic characterization of coagulase-negative staphylococci isolated from human bloodstream infections.}, journal = {Microbial pathogenesis}, volume = {100}, number = {}, pages = {312-318}, doi = {10.1016/j.micpath.2016.10.005}, pmid = {27725281}, issn = {1096-1208}, mesh = {Bacterial Adhesion ; Bacterial Toxins/*analysis/genetics ; Bacterial Typing Techniques ; Biofilms/*growth & development ; Brazil ; Cluster Analysis ; Cross Infection/microbiology ; Genotype ; Hospitals ; Humans ; Polymerase Chain Reaction ; Sepsis/*microbiology ; Staphylococcal Infections/*microbiology ; Staphylococcus/classification/isolation & purification/metabolism/*physiology ; Virulence Factors/analysis/genetics ; }, abstract = {Coagulase-negative staphylococci (CNS) represent one of the most prevalent microorganisms in nosocomial infections worldwide, nevertheless little is known about their pathogenicity features. Thus, our aim was to characterize virulence aspects of CNS isolated from patients with bloodstream infections assisted in hospitals of Belo Horizonte, MG, Brazil. Strains were identified using bioMérieuxVitek[®] and for biofilm production evaluation, Congo Red Agar (CRA) and polystyrene plates were used. PCR was applied to detect icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr. For statistical analyses were used hierarchical cluster, chi-square test and correspondence. 59 strains were analyzed, being S. haemolyticus the most prevalent. On CRA, 96.5% were biofilm producer, whereas on polystyrene plate, 100% showed adhesion at different times evaluated. Regarding genotypic analyses, 15.2%, 38.9%, 8.4%, 49.1%, 76.2%, 23.7%, 1.6%, 30.5% and 38.9% were positive for icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr, respectively. Six clusters were formed and frequency distributions of agr, atlE, icaA, icaB, sea, sec, tsst-1 differed (P < 0.001). In conclusion, all strains were biofilm producer, with high prevalence of atlE, and had potential of toxin production, with high prevalence of sea. According to the group-analyses, icaB showed relationship with the strong adherence in samples.}, } @article {pmid27612675, year = {2016}, author = {Caroline de Abreu Brandi, T and Portela, MB and Lima, PM and Castro, GFBA and Maia, LC and Fonseca-Gonçalves, A}, title = {Demineralizing potential of dental biofilm added with Candida albicans and Candida parapsilosis isolated from preschool children with and without caries.}, journal = {Microbial pathogenesis}, volume = {100}, number = {}, pages = {51-55}, doi = {10.1016/j.micpath.2016.09.003}, pmid = {27612675}, issn = {1096-1208}, mesh = {Animals ; Biofilms/*growth & development ; Candida/isolation & purification/metabolism/*physiology ; Cattle ; Child, Preschool ; Dental Caries/microbiology ; Dental Enamel/metabolism/microbiology ; Humans ; Mouth/microbiology ; Temperature ; Time ; *Tooth Demineralization ; }, abstract = {This study aimed to investigate the demineralizing potential of dental biofilm added of Candida albicans (CA) and Candida parapsilosis (CP), isolated from preschoolers with and without caries. Bovine enamel blocks (n = 48), with initial hardness = 341.50 ± 21,83 kg/mm[2] were fixed in 24 well plates containing culture media. A pool of children saliva (PHS) was the inoculum for biofilm formation in the presence or absence of isolated CA or CP in accordance with each group (G n = 8): G1 - PHS; G2 - PHS + CA isolated from children with caries; G3 - PHS + CP isolated from children with caries; G4 - PHS + CA isolated from children without caries; G5 - PHS + CP isolated from children without caries; and G6 - blank control. The plates were incubated at 37 °C for 5 days, with daily changes of culture media. The microhardness loss percentage (MHL%) of the blocks was calculated, taking in account the hardness values before and after the experiment. Dental biofilm became more cariogenic, independently of the isolated Candida species. The highest MHL% was observed in G4 (85.90 ± 8.72%) and G5 (86.13 ± 6.74%) compared to the others (p < 0.001): G1 (34.30 ± 14,30%) < G2 (59.40 ± 10.56%) and G3 (65.80 ± 6.36%) < G6 (13.68 ± 4.86%) (p < 0.001). C. albicans and C. parapsilosis isolates induced the demineralization of the dental enamel.}, } @article {pmid27594669, year = {2016}, author = {Wang, T and Guan, W and Huang, Q and Yang, Y and Yan, W and Sun, B and Zhao, T}, title = {Quorum-sensing contributes to virulence, twitching motility, seed attachment and biofilm formation in the wild type strain Aac-5 of Acidovorax citrulli.}, journal = {Microbial pathogenesis}, volume = {100}, number = {}, pages = {133-140}, doi = {10.1016/j.micpath.2016.08.039}, pmid = {27594669}, issn = {1096-1208}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Citrullus/microbiology ; Comamonadaceae/genetics/*physiology ; Gene Deletion ; Gene Expression Profiling ; Genetic Complementation Test ; *Locomotion ; *Quorum Sensing ; Seeds/*microbiology ; Virulence ; Virulence Factors/genetics ; }, abstract = {Acidovorax citrulli is a seed-borne pathogen causing bacterial fruit blotch of cucurbits including melon and watermelon. We investigated the roles of quorum sensing in the wild-type group II strain Aac-5 of A. citrulli by generating aacR and aacI knockout mutants and their complementation strains. We found that twitching motility and virulence were reduced, but biofilm formation and seed attachment were increased significantly in the two mutants as compared to the wild type strain. Deletion of aacR and aacI, however, had no effect on swimming motility and polar flagella formation of Aac-5. Furthermore, deletion of aacR resulted in reduced gene expression of hrpE, hrcN and pilT, while deletion of aacI affected only the expression of hrpE and pilT, not hrcN.}, } @article {pmid27544324, year = {2016}, author = {Giongo, JL and de Almeida Vaucher, R and Fausto, VP and Quatrin, PM and Lopes, LQS and Santos, RCV and Gündel, A and Gomes, P and Steppe, M}, title = {Anti-Candida activity assessment of Pelargonium graveolens oil free and nanoemulsion in biofilm formation in hospital medical supplies.}, journal = {Microbial pathogenesis}, volume = {100}, number = {}, pages = {170-178}, doi = {10.1016/j.micpath.2016.08.013}, pmid = {27544324}, issn = {1096-1208}, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Emulsions/pharmacology ; Equipment and Supplies/*microbiology ; Hospitals ; Microbial Sensitivity Tests ; Pelargonium/*chemistry ; Plant Extracts/isolation & purification/*pharmacology ; }, abstract = {Infections due to microbial biofilm formation on the surface of catheters and other medical devices are constantly reported as a major cause of morbidity and mortality in patients admitted to hospitals. Furthermore, sessile cells are more resistant to phagocytosis and most antimicrobial, which complicates the treatment of such infections. Researches aimed at new antimicrobial originating mainly from plants have increased in recent years and the development of new strategies for their release is critical in combating the formation of biofilms. Geranium oil (GO) has proven antimicrobial activity. Because of this, the aim of this study was to develop nanoemulsions containing this oil (NEG) and evaluate its activity after the biofilm formation of Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei in hospital medical supplies. For quantification of the biofilm, crystal violet, total protein, and ATP-bioluminescence assays were used. The results revealed that GO and NEG showed lower MIC for C. albicans and C. tropicalis. The biofilms formed by different species of Candida on the surfaces of polyethylene and polyurethane were quantified. GO and NEG significantly inhibited the formation of biofilms in all species tested on the surfaces of polyethylene. However, NEG antibiofilm has had better activity than GO for C. albicans, C. tropicalis and C. glabrata, according to the surface potential analysis by atomic force microscopy (AFM). The analysis of the biofilm formation on the polyethylene surface by ATP-bioluminescence and CFU showed similar results. In both methods the formation of biofilm in the catheter occurred in greater quantity for C. albicans and C. tropicalis. GO did not significantly inhibit the formation of biofilms only in C. krusei, although NEG significantly increased this activity GO in all species tested when compared to the control training biofilm. The following study shows that the development of NEG may become an effective alternative to reduce the adhesion of microorganisms and prevent infections resulting from the use of some hospital medical materials.}, } @article {pmid27782192, year = {2016}, author = {Zhang, S and Pang, S and Wang, P and Wang, C and Guo, C and Addo, FG and Li, Y}, title = {Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36178}, pmid = {27782192}, issn = {2045-2322}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cluster Analysis ; DNA, Bacterial/chemistry/isolation & purification/metabolism ; Denitrification ; Hydrocharitaceae/growth & development/*microbiology ; Microscopy, Electron, Scanning ; Nitrates/*metabolism ; Proteobacteria/genetics/metabolism/*physiology ; Sequence Analysis, DNA ; Water Microbiology ; }, abstract = {Submerged macrophytes play important roles in constructed wetlands and natural water bodies, as these organisms remove nutrients and provide large surfaces for biofilms, which are beneficial for nitrogen removal, particularly from submerged macrophyte-dominated water columns. However, information on the responses of biofilms to submerged macrophytes and nitrogen molecules is limited. In the present study, bacterial community structure and denitrifiers were investigated in biofilms on the leaves of four submerged macrophytes and artificial plants exposed to two nitrate concentrations. The biofilm cells were evenly distributed on artificial plants but appeared in microcolonies on the surfaces of submerged macrophytes. Proteobacteria was the most abundant phylum in all samples, accounting for 27.3-64.8% of the high-quality bacterial reads, followed by Chloroflexi (3.7-25.4%), Firmicutes (3.0-20.1%), Acidobacteria (2.7-15.7%), Actinobacteria (2.2-8.7%), Bacteroidetes (0.5-9.7%), and Verrucomicrobia (2.4-5.2%). Cluster analysis showed that bacterial community structure can be significantly different on macrophytes versus from those on artificial plants. Redundancy analysis showed that electrical conductivity and nitrate concentration were positively correlated with Shannon index and operational taxonomic unit (OTU) richness (log10 transformed) but somewhat negatively correlated with microbial density. The relative abundances of five denitrifying genes were positively correlated with nitrate concentration and electrical conductivity but negatively correlated with dissolved oxygen.}, } @article {pmid27782161, year = {2016}, author = {Sultana, ST and Call, DR and Beyenal, H}, title = {Maltodextrin enhances biofilm elimination by electrochemical scaffold.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36003}, pmid = {27782161}, issn = {2045-2322}, mesh = {Acinetobacter baumannii/*physiology ; Biofilms/*growth & development ; *Electrochemical Techniques ; Polysaccharides/*chemistry ; Staphylococcus aureus/*physiology ; Tissue Scaffolds/*chemistry ; }, abstract = {Electrochemical scaffolds (e-scaffolds) continuously generate low concentrations of H2O2 suitable for damaging wound biofilms without damaging host tissue. Nevertheless, retarded diffusion combined with H2O2 degradation can limit the efficacy of this potentially important clinical tool. H2O2 diffusion into biofilms and bacterial cells can be increased by damaging the biofilm structure or by activating membrane transportation channels by exposure to hyperosmotic agents. We hypothesized that e-scaffolds would be more effective against Acinetobacter baumannii and Staphylococcus aureus biofilms in the presence of a hyperosmotic agent. E-scaffolds polarized at -600 mVAg/AgCl were overlaid onto preformed biofilms in media containing various maltodextrin concentrations. E-scaffold alone decreased A. baumannii and S. aureus biofilm cell densities by (3.92 ± 0.15) log and (2.31 ± 0.12) log, respectively. Compared to untreated biofilms, the efficacy of the e-scaffold increased to a maximum (8.27 ± 0.05) log reduction in A. baumannii and (4.71 ± 0.12) log reduction in S. aureus biofilm cell densities upon 10 mM and 30 mM maltodextrin addition, respectively. Overall ~55% decrease in relative biofilm surface coverage was achieved for both species. We conclude that combined treatment with electrochemically generated H2O2 from an e-scaffold and maltodextrin is more effective in decreasing viable biofilm cell density.}, } @article {pmid27538491, year = {2016}, author = {Goel, S and Mittal, S and Chaudhary, U}, title = {Role of Non Albicans Candida Spp. and Biofilm in Neonatal ICU.}, journal = {Infectious disorders drug targets}, volume = {16}, number = {3}, pages = {192-198}, doi = {10.2174/1871526516666160818150148}, pmid = {27538491}, issn = {2212-3989}, mesh = {Antifungal Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Candida/classification/drug effects/isolation & purification/*physiology ; Candida albicans/drug effects/isolation & purification/metabolism ; Candida tropicalis/drug effects/isolation & purification/physiology ; Candidemia/*microbiology ; Candidiasis/*microbiology ; Child ; Drug Resistance, Multiple, Fungal ; Fluconazole/pharmacology ; Humans ; Infant, Newborn ; *Intensive Care Units, Neonatal ; Prevalence ; }, abstract = {BACKGROUND: Candida spp. remains the fungal species most commonly associated with biofilm formation. Increase in Candida infections in last decades has almost paralleled the increase and wide spread use of a broad range of medical implant devices mainly in population with impaired host defences. One of the most important characteristics of biofilms is their high level of resistance to antimicrobial drugs.

AIMS AND OBJECTIVES: This study was conducted to know the prevalence of different Candida spp. causing blood stream infections and ability to form biofilm and to evaluate the co relation of biofilm with antifungal drug resistance.

MATERIAL AND METHODS: The present study was conducted on 12464 blood samples for the identification and speciation of various Candida spp. causing blood stream infection over a period of one year. Antifungal susceptibility was performed as per clinical laboratory standard institute guidelines and biofilm formation was detected by method described by Christensen's et al.

RESULTS: Out of total 12464 blood culture received, 1378 (11.05%) were culture positive rest and among culture positive 100 (7.25%) Candida isolates were recovered. C. tropicalis was the commonest (43%) species followed by C. albicans (41%), C. krusei (9%) and C. parapsilosis (7%). A total of 41 Candida isolates were biofilm producers and rest 59 isolates were non-biofilm producers.

CONCLUSION: A changing trend of increased prevalence of non albicans Candida spp. was observed which were resistant to commonly used antifungal fluconazole. Multi drug resistance was more common in biofilm forming Candida isolates.}, } @article {pmid27780306, year = {2017}, author = {Santos, R and Costa, C and Mil-Homens, D and Romão, D and de Carvalho, CC and Pais, P and Mira, NP and Fialho, AM and Teixeira, MC}, title = {The multidrug resistance transporters CgTpo1_1 and CgTpo1_2 play a role in virulence and biofilm formation in the human pathogen Candida glabrata.}, journal = {Cellular microbiology}, volume = {19}, number = {5}, pages = {}, doi = {10.1111/cmi.12686}, pmid = {27780306}, issn = {1462-5822}, mesh = {Animals ; Antifungal Agents/pharmacology ; *Biofilms ; Candida glabrata/drug effects/pathogenicity/*physiology ; Drug Resistance, Multiple ; Ergosterol/metabolism ; Fatty Acids/metabolism ; Fungal Proteins/*physiology ; Gene Expression ; Genes, Fungal ; Hemocytes/microbiology ; Histatins/pharmacology ; Humans ; Larva/microbiology ; Lipid Metabolism ; Membrane Potentials ; Microbial Sensitivity Tests ; Microbial Viability ; Moths ; Multidrug Resistance-Associated Proteins/*physiology ; Phagocytosis ; Virulence ; }, abstract = {The mechanisms of persistence and virulence associated with Candida glabrata infections are poorly understood, limiting the ability to fight this fungal pathogen. In this study, the multidrug resistance transporters CgTpo1_1 and CgTpo1_2 are shown to play a role in C. glabrata virulence. The survival of the infection model Galleria mellonella, infected with C. glabrata, was found to increase upon the deletion of either CgTPO1_1 or CgTPO1_2. The underlying mechanisms were further explored. In the case of CgTpo1_1, this phenotype was found to be consistent with the observation that it confers resistance to antimicrobial peptides (AMP), such as the human AMP histatin-5. The deletion of CgTPO1_2, on the other hand, was found to limit the survival of C. glabrata cells when exposed to phagocytosis and impair biofilm formation. Interestingly, CgTPO1_2 expression was found to be up-regulated during biofilm formation, but and its deletion leads to a decreased expression of adhesin-encoding genes during biofilm formation, which is consistent with a role in biofilm formation. CgTPO1_2 expression was further seen to decrease plasma membrane potential and affect ergosterol and fatty acid content. Altogether, CgTpo1_1 and CgTpo1_2 appear to play an important role in the virulence of C. glabrata infections, being at the cross-road between multidrug resistance and pathogenesis.}, } @article {pmid27779811, year = {2017}, author = {Zaborowska, M and Tillander, J and Brånemark, R and Hagberg, L and Thomsen, P and Trobos, M}, title = {Biofilm formation and antimicrobial susceptibility of staphylococci and enterococci from osteomyelitis associated with percutaneous orthopaedic implants.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {105}, number = {8}, pages = {2630-2640}, doi = {10.1002/jbm.b.33803}, pmid = {27779811}, issn = {1552-4981}, mesh = {Adult ; Aged ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Enterococcus faecalis/*physiology ; Female ; Humans ; Male ; Middle Aged ; Osteomyelitis/*microbiology ; Prostheses and Implants/*microbiology ; *Staphylococcal Infections ; Staphylococcus aureus/*physiology ; }, abstract = {Staphylococci and enterococci account for most deep infections associated with bone-anchored percutaneous implants for amputation treatment. Implant-associated infections are difficult to treat; therefore, it is important to investigate if these infections have a biofilm origin and to determine the biofilm antimicrobial susceptibility to improve treatment strategies. The aims were: (i) to test a novel combination of the Calgary biofilm device and a custom-made susceptibility MIC plate (Sensititre[®]), (ii) to determine the biofilm formation and antimicrobial resistance in clinical isolates causing implant-associated osteomyelitis, and (iii) to describe the associated clinical outcome. Enterococci and staphylococci were characterized by microtitre plate assay, Congo Red Agar plate test, and PCR. Biofilm susceptibility to 10 antimicrobials and its relationship to treatment outcomes were determined. The majority of the strains produced biofilm in vitro showing inter- and intraspecies differences. Biofilms showed a significantly increased antimicrobial resistance compared with their planktonic counterparts. Slime-producing strains tolerated significantly higher antimicrobial concentrations compared with non-producers. All seven staphylococcal strains carried ica genes, but two did not produce slime. The degree of biofilm formation and up-regulated antibiotic resistance may translate into a variable risk of treatment failure. This new method set-up allows for the reproducible determination of minimum biofilm eradication concentration of antimicrobial agents, which may guide future antimicrobial treatment decisions in orthopaedic implant-associated infection. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2630-2640, 2017.}, } @article {pmid27777212, year = {2016}, author = {Xu, L and Lin, DS and Yang, J and Li, J and Li, B}, title = {[Effect of Klebsiella pneumoniae KbvR regulator on bacterial biofilm formation and capsular synthesis].}, journal = {Nan fang yi ke da xue xue bao = Journal of Southern Medical University}, volume = {36}, number = {10}, pages = {1435-1439}, pmid = {27777212}, issn = {1673-4254}, mesh = {*Bacterial Capsules ; Bacterial Proteins/*metabolism ; *Biofilms ; Gene Deletion ; Klebsiella pneumoniae/*cytology ; Plasmids ; Promoter Regions, Genetic ; }, abstract = {OBJECTIVE: To construct the KbvR gene of LuxR family deletion mutant and complementation strains from Klebsiella pneumoniae NTUH-K2044 and analyze the effect of KbvR on bacterial growth, biofilm formation and capsular synthesis.

METHODS: A KbvR gene deletion mutant strain was constructed using the suicide vector pKO3-Km, and the gene fragment including KbvR coding region, promoter area and transcription termination area were amplified and cloned into pGEM-T-easy plasmid to construct KbvR complementation strain. The growth curves of the wild-type strain, KbvR gene deletion mutant strain and complementation strain were observed to assess the effect of KbvR on bacterial growth. Crystal violet staining method was used to measure the effect of KbvR on biofilm formation; the effect of KbvR on capsular synthesis was detected using string test, centrifugal test and RT-PCR.

RESULTS: The KbvR deletion mutant and complementation strains were constructed successfully. KbvR gene did not affect the growth of the bacteria, but biofilm formation and capsular synthesis were attenuated in KbvR deletion mutant strain.

CONCLUSION: As a transcription factor of the LuxR family orphans of the quorum sensing system, KbvR positively regulates bacterial biofilm formation by affecting capsular synthesis.}, } @article {pmid27776509, year = {2016}, author = {Wigneswaran, V and Nielsen, KF and Sternberg, C and Jensen, PR and Folkesson, A and Jelsbak, L}, title = {Biofilm as a production platform for heterologous production of rhamnolipids by the non-pathogenic strain Pseudomonas putida KT2440.}, journal = {Microbial cell factories}, volume = {15}, number = {1}, pages = {181}, pmid = {27776509}, issn = {1475-2859}, mesh = {*Biofilms ; Glycolipids/*biosynthesis ; Pseudomonas aeruginosa/genetics/metabolism ; Pseudomonas putida/genetics/metabolism/*physiology ; }, abstract = {BACKGROUND: Although a transition toward sustainable production of chemicals is needed, the physiochemical properties of certain biochemicals such as biosurfactants make them challenging to produce in conventional bioreactor systems. Alternative production platforms such as surface-attached biofilm populations could potentially overcome these challenges. Rhamnolipids are a group of biosurfactants highly relevant for industrial applications. However, they are mainly produced by the opportunistic pathogen Pseudomonas aeruginosa using hydrophobic substrates such as plant oils. As the biosynthesis is tightly regulated in P. aeruginosa a heterologous production of rhamnolipids in a safe organism can relive the production from many of these limitations and alternative substrates could be used.

RESULTS: In the present study, heterologous production of biosurfactants was investigated using rhamnolipids as the model compound in biofilm encased Pseudomonas putida KT2440. The rhlAB operon from P. aeruginosa was introduced into P. putida to produce mono-rhamnolipids. A synthetic promoter library was used in order to bypass the normal regulation of rhamnolipid synthesis and to provide varying expression levels of the rhlAB operon resulting in different levels of rhamnolipid production. Biosynthesis of rhamnolipids in P. putida decreased bacterial growth rate but stimulated biofilm formation by enhancing cell motility. Continuous rhamnolipid production in a biofilm was achieved using flow cell technology. Quantitative and structural investigations of the produced rhamnolipids were made by ultra performance liquid chromatography combined with high resolution mass spectrometry (HRMS) and tandem HRMS. The predominant rhamnolipid congener produced by the heterologous P. putida biofilm was mono-rhamnolipid with two C10 fatty acids.

CONCLUSION: This study shows a successful application of synthetic promoter library in P. putida KT2440 and a heterologous biosynthesis of rhamnolipids in biofilm encased cells without hampering biofilm capabilities. These findings expands the possibilities of cultivation setups and paves the way for employing biofilm flow systems as production platforms for biochemicals, which as a consequence of physiochemical properties are troublesome to produce in conventional fermenter setups, or for production of compounds which are inhibitory or toxic to the production organisms.}, } @article {pmid27702793, year = {2016}, author = {Ferreira, C and Gonçalves, B and Vilas Boas, D and Oliveira, H and Henriques, M and Azeredo, J and Silva, S}, title = {Candida tropicalis biofilm and human epithelium invasion is highly influenced by environmental pH.}, journal = {Pathogens and disease}, volume = {74}, number = {8}, pages = {}, doi = {10.1093/femspd/ftw101}, pmid = {27702793}, issn = {2049-632X}, mesh = {*Biofilms ; Candida tropicalis/isolation & purification/pathogenicity/*physiology ; Candidiasis/*microbiology ; *Environment ; Epithelium/*microbiology ; Humans ; Hydrogen-Ion Concentration ; Mucous Membrane/microbiology ; }, abstract = {OBJECTIVE: The main goal of this study was to investigate the role of pH on Candida tropicalis virulence determinants, namely the ability to form biofilms and to colonize/invade reconstituted human vaginal epithelia.

METHODS: Biofilm formation was evaluated by enumeration of cultivable cells, total biomass quantification and structural analysis by scanning electron microscopy and confocal laser scanning microscopy. Candida tropicalis human vaginal epithelium colonization and invasiveness were examined qualitatively by epifluorescence microscopy and quantitatively by a novel quantitative real-time PCR protocol for Candida quantification in tissues.

RESULTS: The results revealed that environmental pH influences C. tropicalis biofilm formation as well as the colonization and potential to invade human epithelium with intensification at neutral and alkaline conditions compared to acidic conditions.

CONCLUSIONS: For the first time, we have demonstrated that C. tropicalis biofilm formation and invasion is highly influenced by environmental pH.}, } @article {pmid27676452, year = {2016}, author = {Cho, H and Huang, X and Lan Piao, Y and Eun Kim, D and Yeon Lee, S and Jeong Yoon, E and Hee Park, S and Lee, K and Ho Jang, C and Zhan, CG}, title = {Molecular modeling and redesign of alginate lyase from Pseudomonas aeruginosa for accelerating CRPA biofilm degradation.}, journal = {Proteins}, volume = {84}, number = {12}, pages = {1875-1887}, doi = {10.1002/prot.25171}, pmid = {27676452}, issn = {1097-0134}, support = {UL1 TR000117/TR/NCATS NIH HHS/United States ; }, mesh = {Acetylation ; Alginates/*chemistry/metabolism ; Amino Acid Sequence ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism/pharmacology ; Biocatalysis ; Biofilms/*drug effects/growth & development ; Ciprofloxacin/pharmacology ; Cloning, Molecular ; Drug Resistance, Bacterial/drug effects ; Drug Synergism ; Drug Therapy, Combination ; Escherichia coli/genetics/metabolism ; Gene Expression ; Glucuronic Acid/chemistry/metabolism ; Hexuronic Acids/chemistry/metabolism ; Hydrolysis ; Kinetics ; Molecular Dynamics Simulation ; Mutation ; Penicillanic Acid/analogs & derivatives/pharmacology ; Piperacillin/pharmacology ; Piperacillin, Tazobactam Drug Combination ; Polysaccharide-Lyases/*genetics/metabolism/pharmacology ; Protein Domains ; Protein Engineering ; Protein Structure, Secondary ; Pseudomonas aeruginosa/chemistry/*drug effects/enzymology/growth & development ; Recombinant Proteins/genetics/metabolism/pharmacology ; Sequence Alignment ; Structural Homology, Protein ; }, abstract = {Administration of an efficient alginate lyase (AlgL) or AlgL mutant may be a promising therapeutic strategy for treatment of cystic fibrosis patients with Pseudomonas aeruginosa infections. Nevertheless, the catalytic activity of wild-type AlgL is not sufficiently high. It is highly desired to design and discover an AlgL mutant with significantly improved catalytic efficiency against alginate substrates. For the purpose of identifying an AlgL mutant with significantly improved catalytic activity, in this study, we first constructed and validated a structural model of AlgL interacting with substrate, providing a better understanding of the interactions between AlgL and its substrate. Based on the modeling insights, further enzyme redesign and experimental testing led to discovery of AlgL mutants, including the K197D/K321A mutant, with significantly improved catalytic activities against alginate and acetylated alginate in ciprofloxacin-resistant P. aeruginosa (CRPA) biofilms. Further anti-biofilm activity assays have confirmed that the K197D/K321A mutant with piperacillin/tazobactam is indeed effective in degrading the CRPA biofilms. Co-administration of the potent mutant AlgL and an antibiotic (such as a nebulizer) could be effective for therapeutic treatment of CRPA-infected patients with cystic fibrosis. Proteins 2016; 84:1875-1887. © 2016 Wiley Periodicals, Inc.}, } @article {pmid27500808, year = {2016}, author = {Bodelón, G and Montes-García, V and López-Puente, V and Hill, EH and Hamon, C and Sanz-Ortiz, MN and Rodal-Cedeira, S and Costas, C and Celiksoy, S and Pérez-Juste, I and Scarabelli, L and La Porta, A and Pérez-Juste, J and Pastoriza-Santos, I and Liz-Marzán, LM}, title = {Detection and imaging of quorum sensing in Pseudomonas aeruginosa biofilm communities by surface-enhanced resonance Raman scattering.}, journal = {Nature materials}, volume = {15}, number = {11}, pages = {1203-1211}, pmid = {27500808}, issn = {1476-4660}, support = {267867/ERC_/European Research Council/International ; }, mesh = {*Biofilms ; *Molecular Imaging ; Pseudomonas aeruginosa/*cytology/*physiology ; *Quorum Sensing ; *Spectrum Analysis, Raman ; }, abstract = {Most bacteria in nature exist as biofilms, which support intercellular signalling processes such as quorum sensing (QS), a cell-to-cell communication mechanism that allows bacteria to monitor and respond to cell density and changes in the environment. As QS and biofilms are involved in the ability of bacteria to cause disease, there is a need for the development of methods for the non-invasive analysis of QS in natural bacterial populations. Here, by using surface-enhanced resonance Raman scattering spectroscopy, we report rationally designed nanostructured plasmonic substrates for the in situ, label-free detection of a QS signalling metabolite in growing Pseudomonas aeruginosa biofilms and microcolonies. The in situ, non-invasive plasmonic imaging of QS in biofilms provides a powerful analytical approach for studying intercellular communication on the basis of secreted molecules as signals.}, } @article {pmid27776306, year = {2016}, author = {Brosseau, C and Émile, B and Labelle, MA and Laflamme, É and Dold, PL and Comeau, Y}, title = {Compact secondary treatment train combining a lab-scale moving bed biofilm reactor and enhanced flotation processes.}, journal = {Water research}, volume = {106}, number = {}, pages = {571-582}, doi = {10.1016/j.watres.2016.10.019}, pmid = {27776306}, issn = {1879-2448}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors ; *Waste Disposal, Fluid ; Wastewater ; }, abstract = {High-rate wastewater processes are receiving a renewed interest to obtain energy positive/efficient water resource recovery facilities. An innovative treatment train combining a high-rate moving bed biofilm reactor (HR-MBBR) with an enhanced flotation process was studied. The two objectives of this work were 1) to maximize the conversion of soluble organics to particulate matter in an HR-MBBR and 2) to maximize the particulate matter recovery from the HR-MBBR effluent by green chemicals to enhance biogas production by anaerobic digestion. To achieve these objectives, lab-scale MBBRs fed with synthetic soluble wastewater were operated at organic loading rates (OLRs) between 4 and 34 kg COD m[-3] reactor d[-1] corresponding to hydraulic retention times (HRTs) between 6 and 54 min. Colloidal and soluble chemical oxygen demand (COD) removal efficiency in the HR-MBBR increased with HRT to reach a plateau of 85% at an HRT longer than 27 min. Carrier clogging observed at an OLR higher than 16 kg COD m[-3] d[-1] (HRT < 13 min) resulted in about 23% loss in colloidal and soluble COD removal efficiency. Thus, the recommended parameters were between 22 and 37 min and between 6 and 10 kg COD m[-3] d[-1] for the HRT and the OLR, respectively, to maximize the conversion of soluble organics to particulate matter. Total suspended solids (TSS) recovery of 58-85% and 90-97% were achieved by enhanced flotation using green and unbiodegradable chemicals, respectively, corresponding to a TSS effluent concentration below 14 and 7 mg TSS/L. Among the synthetic polymers tested, a high molecular weight and low charge density cationic polyacrylamide was found to give the best results with less than 2 mg TSS/L in the clarified effluent (97% TSS recovery). Green chemicals, although performing slightly less for solids separation than unbiodegradable chemicals, achieved a mean TSS concentration of 10 ± 3 mg/L in the clarified effluent.}, } @article {pmid27775462, year = {2016}, author = {Ravn, C and Furustrand Tafin, U and Bétrisey, B and Overgaard, S and Trampuz, A}, title = {Reduced ability to detect surface-related biofilm bacteria after antibiotic exposure under in vitro conditions.}, journal = {Acta orthopaedica}, volume = {87}, number = {6}, pages = {644-650}, pmid = {27775462}, issn = {1745-3682}, mesh = {Anti-Bacterial Agents/*administration & dosage/therapeutic use ; Bacteria/*drug effects ; Biofilms/*drug effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Humans ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/*drug therapy/microbiology ; }, abstract = {Background and purpose - Antibiotic treatment of patients before specimen collection reduces the ability to detect organisms by culture. We investigated the suppressive effect of antibiotics on the growth of non-adherent, planktonic, and surface-related biofilm bacteria in vitro by using sonication and microcalorimetry methods. Patients and methods - Biofilms of Staphylococcus aureus, S. epidermidis, Escherichia coli, and Propionibacterium acnes were formed on porous glass beads and exposed for 24 h to antibiotic concentrations from 1 to 1,024 times the minimal inhibitory concentration (MIC) of vancomycin, daptomycin, rifampin, flucloxacillin, or ciprofloxacin. The beads were then sonicated to dislodge biofilm, followed by culture and measurement of growth-related heat flow by microcalorimetry of the resulting sonication fluid. Results - Vancomycin did not inhibit the heat flow of staphylococci and P. acnes at concentrations ≤1,024 μg/mL, whereas flucloxacillin at >128 μg/mL inhibited S. aureus. Daptomycin inhibited heat flow of S. aureus, S. epidermidis, and P. acnes at lower concentrations (32-128 times MIC, p < 0.001). Rifampin showed inconsistent results in staphylococci due to random emergence of resistance, which was observed at concentrations ≤1,024 times MIC (i.e. 8 μg/mL). Ciprofloxacin inhibited heat flow of E. coli at ≥4 times MIC (i.e. ≥ 0.06 μg/mL). Interpretation - Whereas time-dependent antibiotics (i.e. vancomycin and flucloxacillin) showed only weak growth suppression, concentration-dependent drugs (i.e. daptomycin and ciprofloxacin) had a strong suppressive effect on bacterial growth and reduced the ability to detect planktonic and biofilm bacteria. Exposure to rifampin rapidly caused emergence of resistance. Our findings indicate that preoperative administration of antibiotics may have heterogeneous effects on the ability to detect biofilm bacteria.}, } @article {pmid27771586, year = {2017}, author = {Peixoto, LR and Rosalen, PL and Ferreira, GL and Freires, IA and de Carvalho, FG and Castellano, LR and de Castro, RD}, title = {Antifungal activity, mode of action and anti-biofilm effects of Laurus nobilis Linnaeus essential oil against Candida spp.}, journal = {Archives of oral biology}, volume = {73}, number = {}, pages = {179-185}, doi = {10.1016/j.archoralbio.2016.10.013}, pmid = {27771586}, issn = {1879-1506}, mesh = {Antifungal Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/metabolism/physiology ; Candida albicans/drug effects/growth & development ; Cell Membrane Permeability/drug effects ; Ergosterol/pharmacology ; Eugenol/analogs & derivatives/pharmacology ; Gas Chromatography-Mass Spectrometry/methods ; Laurus/*chemistry ; Monoterpenes/pharmacology ; Nystatin/pharmacology ; Oils, Volatile/chemistry/isolation & purification/*pharmacology ; Plant Extracts/chemistry/isolation & purification/pharmacology ; Sesquiterpenes/pharmacology ; Sorbitol/pharmacology ; }, abstract = {OBJECTIVE: The present study demonstrated the antifungal potential of the chemically characterized essential oil (EO) of Laurus nobilis L. (bay laurel) against Candida spp. biofilm adhesion and formation, and further established its mode of action on C. albicans.

METHODS: L. nobilis EO was obtained and tested for its minimum inhibitory and fungicidal concentrations (MIC/MFC) against Candida spp., as well as for interaction with cell wall biosynthesis and membrane ionic permeability. Then we evaluated its effects on the adhesion, formation, and reduction of 48hC. albicans biofilms. The EO phytochemical profile was determined by gas chromatography coupled to mass spectrometry (GC/MS).

RESULTS: The MIC and MFC values of the EO ranged from (250 to 500) μg/mL. The MIC values increased in the presence of sorbitol (osmotic protector) and ergosterol, which indicates that the EO may affect cell wall biosynthesis and membrane ionic permeability, respectively. At 2 MIC the EO disrupted initial adhesion of C. albicans biofilms (p<0.05) and affected biofilm formation with no difference compared to nystatin (p>0.05). When applied for 1min, every 8h, for 24h and 48h, the EO reduced the amount of C. albicans mature biofilm with no difference in relation to nystatin (p>0.05). The phytochemical analysis identified isoeugenol as the major compound (53.49%) in the sample.

CONCLUSIONS: L. nobilis EO has antifungal activity probably due to monoterpenes and sesquiterpenes in its composition. This EO may affect cell wall biosynthesis and membrane permeability, and showed deleterious effects against C. albicans biofilms.}, } @article {pmid27770916, year = {2017}, author = {Montero, JF and Tajiri, HA and Barra, GM and Fredel, MC and Benfatti, CA and Magini, RS and Pimenta, AL and Souza, JC}, title = {Biofilm behavior on sulfonated poly(ether-ether-ketone) (sPEEK).}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {70}, number = {Pt 1}, pages = {456-460}, doi = {10.1016/j.msec.2016.09.017}, pmid = {27770916}, issn = {1873-0191}, mesh = {Benzophenones ; Biofilms/*drug effects ; Enterococcus faecalis/drug effects ; Ketones/*pharmacology ; Magnetic Resonance Spectroscopy ; Microscopy, Electron, Scanning ; Plankton/drug effects/growth & development ; Polyethylene Glycols/*pharmacology ; Polymers ; Spectroscopy, Fourier Transform Infrared ; Streptococcus mutans/drug effects ; Sulfonic Acids/*pharmacology ; Thermogravimetry ; }, abstract = {Poly(ether-ether-ketone) (PEEK) has also shown to be very attractive for incorporating therapeutic compounds thanks to a sulfonation process which modifies the material structure resulting in a sulfonated-PEEK (sPEEK). Concerning biomedical applications, the objective of this work was to evaluate the influence of different sulfonation degree of sPEEK on the biofilm growth. PEEK samples were functionalized by using sulphuric acid (98%) and then dissolved into dimethyl-sulfoxide. A dip coating technique was used to synthesize sPEEK thin films. The sulfonation degree of the materials was analyzed by FT-IR, H NMR, TG and IEC. The surfaces were characterized by scanning electron microscopy, profilometry and contact angle analyses. Subsequently, the biofilm formation on sulfonated-PEEK based on Streptococcus mutans and Enterococcus faecalis was measured by spectrophotometry, colony forming units (CFUmL[-1]) and SEM. Results obtained from thermal and chemical analyses showed an intensification in sulfonation degree for sPEEK at 2 and 2.5h. The E. faecalis or S. mutans biofilm growth revealed statistically significant differences (p<0.05) between 2 and 3h sulfonation groups. A significant decrease (p<0.05) in CFUmL[-1] was recorded for S. mutans or E. faecalis biofilm grown on 2.5 or 3h sPEEK. Regarding the thermal-chemical and microbiologic analyses, the sulfonation degree of sPEEK ranging from 2 up to 3h was successful capable to decrease the biofilm growth. That revealed an alternative strategy to embed anti-biofilm and therapeutic compounds into PEEK avoiding infections in biomedical applications.}, } @article {pmid27696655, year = {2016}, author = {de Carvalho, MP and Gulotta, G and do Amaral, MW and Lünsdorf, H and Sasse, F and Abraham, WR}, title = {Coprinuslactone protects the edible mushroom Coprinus comatus against biofilm infections by blocking both quorum-sensing and MurA.}, journal = {Environmental microbiology}, volume = {18}, number = {11}, pages = {4254-4264}, doi = {10.1111/1462-2920.13560}, pmid = {27696655}, issn = {1462-2920}, mesh = {Alkyl and Aryl Transferases/*genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Coprinus/*chemistry/metabolism ; Fruiting Bodies, Fungal/chemistry/metabolism ; Glycolipids/metabolism ; Lactones/metabolism/*pharmacology ; Pseudomonas aeruginosa/drug effects/enzymology/*physiology ; Quorum Sensing/*drug effects ; Staphylococcus aureus/*drug effects/enzymology/physiology ; Vegetables/chemistry/metabolism/*microbiology ; }, abstract = {Pathogens embedded in biofilms are involved in many infections and are very difficult to treat with antibiotics because of higher resistance compared with planktonic cells. Therefore, new approaches for their control are urgently needed. One way to search for biofilm dispersing compounds is to look at defense strategies of organisms exposed to wet environments, which makes them prone to biofilm infections. It is reasonable to assume that mushrooms have developed mechanisms to control biofilms on their sporocarps (fruiting bodies). A preliminary screening for biofilms on sporocarps revealed several species with few or no bacteria on their sporocarps. From the edible mushroom Coprinus comatus where no bacteria on the sporocarp could be detected (3R,4S)-2-methylene-3,4-dihydroxypentanoic acid 1,4-lactone, named coprinuslactone, was isolated. Coprinuslactone interfered with quorum-sensing and dispersed biofilms of Pseudomonas aeruginosa, where it also reduced the formation of the pathogenicity factors pyocyanin and rhamnolipid B. Coprinuslactone also damaged Staphylococcus aureus cells in biofilms at subtoxic concentrations. Furthermore, it inhibited UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), essential for bacterial cell wall synthesis. These two modes of action ensure the inhibition of a broad spectrum of pathogens on the fruiting body but may also be useful for future clinical applications.}, } @article {pmid27693709, year = {2016}, author = {Pontes, C and Alves, M and Santos, C and Ribeiro, MH and Gonçalves, L and Bettencourt, AF and Ribeiro, IA}, title = {Can Sophorolipids prevent biofilm formation on silicone catheter tubes?.}, journal = {International journal of pharmaceutics}, volume = {513}, number = {1-2}, pages = {697-708}, doi = {10.1016/j.ijpharm.2016.09.074}, pmid = {27693709}, issn = {1873-3476}, mesh = {Adsorption ; Biofilms/*drug effects ; Catheters/*microbiology ; Cell Line ; Cell Survival/drug effects ; Escherichia coli/drug effects/physiology ; Humans ; Lipids/biosynthesis/chemistry/*pharmacology ; Octoxynol/chemistry ; Saccharomycetales/metabolism ; *Silicone Elastomers/chemistry ; Sodium Dodecyl Sulfate/chemistry ; Staphylococcus aureus/drug effects/physiology ; Surface-Active Agents/chemistry ; }, abstract = {Given the impact of biofilms in health care environment and the increasing antibiotic resistance and/or tolerance, new strategies for preventing that occurrence in medical devices are obligatory. Thus, biomaterials surface functionalization with active compounds can be a valuable approach. In the present study the ability of the biosurfactants sophorolipids to prevent biofilms formation on silicone rubber aimed for medical catheters was investigated. Sophorolipids produced by Starmerella bombicola, identified by HPLC-MS/MS were used to cover silicone and surface characterization was evaluated through contact angle measurements and FTIR-ATR. Results revealed that sophorolipids presence on silicone surface decreased the hydrophobicity of the material and biofilm formation of Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. Antibiofilm activity was evaluated through different methods and was more pronounced against S. aureus. Furthermore, biocompatibility of silicone specimens with HaCaT cells was also obtained. From this study it was possible to conclude that sophorolipids seem to be a favourable approach for coating silicone catheters. Such compounds may represent a novel source of antibiofilm agents for technological development passing through strategies of permanent functionalization of surfaces.}, } @article {pmid27638425, year = {2017}, author = {Sun, L and Chen, H and Lin, W and Lin, X}, title = {Quantitative proteomic analysis of Edwardsiella tarda in response to oxytetracycline stress in biofilm.}, journal = {Journal of proteomics}, volume = {150}, number = {}, pages = {141-148}, doi = {10.1016/j.jprot.2016.09.006}, pmid = {27638425}, issn = {1876-7737}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Drug Resistance, Bacterial ; Edwardsiella tarda/*drug effects/metabolism/physiology ; Enterobacteriaceae Infections/drug therapy/metabolism/microbiology ; Microbial Sensitivity Tests ; Oxytetracycline/*pharmacology ; Proteomics/*methods ; }, abstract = {UNLABELLED: Edwardsiella tarda is a virulent fish pathogen that causes extensive economic losses in the aquaculture industry worldwide. The antibiotic resistance status of E. tarda is high, especially in the biofilm status; however, the mechanisms underlying its resistance remain largely unknown. In this study, isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomics methods were used to compare the differential expression of E. tarda in response to oxytetracycline (OXY) stress in biofilm. Additional bioinformatics analysis demonstrated an increasing abundance of translation-related proteins, especially ribosomal subunits, and a decreasing abundance of key metabolic pathways underlying the adaptation of E. tarda to OXY in biofilm. We performed Western blotting and quantitative PCR (qPCR) analyses to validate selected proteomics results, and measured enzyme activity to verify the antibiotic resistance functions of central metabolic pathways. In addition, we examined the antibiotic susceptibility of a mutant of an NADP-dependent malic enzyme (MaeB), which is involved in the bacterial tricarboxylic acid cycle, and found significantly increased resistance to OXY in biofilm. Our findings demonstrate the importance of central metabolic pathways in the antibiotic resistance of E. tarda to bacterial biofilms and provide insight into the prevention of this resistance, which would aid in disease control.

BIOLOGICAL SIGNIFICANCE: The antibiotics resistance mechanisms in E. tarda have been well documented recently; however, its response to antibiotics in biofilms remains elusive. Our current study is the first exploratory report investigating this aspect via an iTARQ-based quantitative proteomics method. Several important proteins, related processes, and metabolic pathways were found to be involved in OXY fitness in biofilm status. Most importantly, the depletion of the maeB gene decreased the susceptibility of E. tarda to OXY indicating the important role of central metabolic pathways in antibiotics resistance in biofilm.}, } @article {pmid27770500, year = {2017}, author = {Hirota, K and Yumoto, H and Sapaar, B and Matsuo, T and Ichikawa, T and Miyake, Y}, title = {Pathogenic factors in Candida biofilm-related infectious diseases.}, journal = {Journal of applied microbiology}, volume = {122}, number = {2}, pages = {321-330}, doi = {10.1111/jam.13330}, pmid = {27770500}, issn = {1365-2672}, mesh = {*Biofilms ; Candida/classification/physiology ; Candida albicans/pathogenicity/*physiology ; Candidiasis/microbiology ; DNA/metabolism ; Humans ; Hyphae/physiology ; Quorum Sensing ; Respiratory Tract Infections/microbiology ; Virulence Factors/metabolism ; }, abstract = {Candida albicans is a commonly found member of the human microflora and is a major human opportunistic fungal pathogen. A perturbation of the microbiome can lead to infectious diseases caused by various micro-organisms, including C. albicans. Moreover, the interactions between C. albicans and bacteria are considered to play critical roles in human health. The major biological feature of C. albicans, which impacts human health, resides in its ability to form biofilms. In particular, the extracellular matrix (ECM) of Candida biofilm plays a multifaceted role and therefore may be considered as a highly attractive target to combat biofilm-related infectious diseases. In addition, extracellular DNA (eDNA) also plays a crucial role in Candida biofilm formation and its structural integrity and induces the morphological transition from yeast to the hyphal growth form during C. albicans biofilm development. This review focuses on pathogenic factors such as eDNA in Candida biofilm formation and its ECM production and provides meaningful information for future studies to develop a novel strategy to battle infectious diseases elicited by Candida-formed biofilm.}, } @article {pmid27769914, year = {2017}, author = {Beytollahi, L and Pourhajibagher, M and Chiniforush, N and Ghorbanzadeh, R and Raoofian, R and Pourakbari, B and Bahador, A}, title = {The efficacy of photodynamic and photothermal therapy on biofilm formation of Streptococcus mutans: An in vitro study.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {17}, number = {}, pages = {56-60}, doi = {10.1016/j.pdpdt.2016.10.006}, pmid = {27769914}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Humans ; Indocyanine Green/administration & dosage/pharmacology ; Lasers, Semiconductor ; Photochemotherapy/methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Phototherapy/*methods ; Streptococcus mutans/*drug effects ; Tolonium Chloride/administration & dosage/pharmacology ; }, abstract = {BACKGROUND: The alternative antibacterial treatments of photodynamic therapy (PDT) and photothermal therapy (PTT) significantly affect microbiota inactivation. The aim of the present research was the assessment of the antimicrobial and anti-biofilm effects of PDT with toluidine blue O (TBO) and PTT with indocyanine green (ICG) on Streptococcus mutans as a cariogenic bacterium.

MATERIALS AND METHODS: The S. mutans ATCC 35668 strain was treated with final concentrations of 0.1mg/mL TBO and 1mg/mL ICG with energy densities of 17.18 and 15.62J/cm[2], respectively. Cell viability was evaluated after culturing and anti-biofilm potential was analyzed using crystal violet assay and scanning electron microscopy.

RESULTS: The number of S. mutans colony forming unit (CFU)/mL was significantly lower in the groups submitted to PDT (12.5-100μg/mL TBO) and PTT (62.5-1000μg/mL) compared to the control (untreated group). 0.1mg/mL TBO-PDT and 1mg/mL ICG-PTT showed stronger inhibitory effects on biofilm formation in S. mutans than other concentration levels, with a reduction of 63.87% and 67.3%, respectively.

CONCLUSION: Photo-elimination by high concentrations of TBO-PDT and ICG-PTT exhibited significantly stronger inhibitory effects on biofilm formation and cell viability in S. mutans.}, } @article {pmid27769678, year = {2016}, author = {Kim, AR and Ahn, KB and Kim, HY and Seo, HS and Yun, CH and Han, SH}, title = {Serine-rich Repeat Adhesin Gordonii Surface Protein B is Important for Streptococcus gordonii Biofilm Formation.}, journal = {Journal of endodontics}, volume = {42}, number = {12}, pages = {1767-1772}, doi = {10.1016/j.joen.2016.08.016}, pmid = {27769678}, issn = {1878-3554}, mesh = {Adhesins, Bacterial/*metabolism ; Bacterial Adhesion ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Bacterial Proteins/genetics/*pharmacology ; Biofilms/*drug effects/*growth & development ; Dentin/microbiology ; Humans ; Microscopy, Electron, Scanning ; Mutation ; Serine/*metabolism ; Streptococcus gordonii/genetics/growth & development/isolation & purification/*metabolism ; Sucrose/metabolism ; }, abstract = {INTRODUCTION: Streptococcus gordonii is a predominant member of the oral microflora and has been isolated from root canals of teeth with refractory apical periodontitis. Biofilm formation is important for various dental diseases, and S. gordonii is involved in dental biofilm formation as an early colonizer. Although serine-rich repeat (SRR) adhesins of S. gordonii such as gordonii surface protein B (GspB) are associated with bacterial colonization, the role of GspB in biofilm formation is not clearly understood. In the present study, we investigated the effect of S. gordonii GspB on biofilm formation using wild-type and GspB-deficient mutant S. gordonii strains.

METHODS: Confocal microscopy and crystal violet assay were used to determine biofilm formation. Bacterial growth was examined by measuring optical density with spectrometry. Bacterial adherence and biofilm on the culture plate and human dentin slices were visualized with a scanning electron microscope.

RESULTS: The GspB-deficient S. gordonii mutant strain was less potent than the wild-type strain in biofilm formation. Of note, there was no difference in the bacterial growth rate between the mutant and wild-type strains. Differences in biofilm-forming ability between the wild-type and mutant strains were more distinct in the sucrose-supplemented media. Furthermore, the GspB-deficient mutant exhibited attenuated formation of aggregates on the surface of the culture plate and human dentin slices.

CONCLUSIONS: These results suggest that GspB is important for S. gordonii biofilm formation, which may contribute to the development of dental biofilm-associated diseases.}, } @article {pmid27769259, year = {2016}, author = {Tong, X and Barberi, TT and Botting, CH and Sharma, SV and Simmons, MJ and Overton, TW and Goss, RJ}, title = {Rapid enzyme regeneration results in the striking catalytic longevity of an engineered, single species, biocatalytic biofilm.}, journal = {Microbial cell factories}, volume = {15}, number = {1}, pages = {180}, pmid = {27769259}, issn = {1475-2859}, support = {614779/ERC_/European Research Council/International ; }, mesh = {Biocatalysis ; *Biofilms ; Catalysis ; Chromatography, Liquid ; Enzymes/biosynthesis/genetics/*metabolism ; Genetic Engineering/*methods ; Mass Spectrometry ; Recombinant Proteins/biosynthesis/genetics/metabolism ; }, abstract = {BACKGROUND: Engineering of single-species biofilms for enzymatic generation of fine chemicals is attractive. We have recently demonstrated the utility of an engineered Escherichia coli biofilm as a platform for synthesis of 5-halotryptophan. E. coli PHL644, expressing a recombinant tryptophan synthase, was employed to generate a biofilm. Its rapid deposition, and instigation of biofilm formation, was enforced by employing a spin-down method. The biofilm presents a large three-dimensional surface area, excellent for biocatalysis. The catalytic longevity of the engineered biofilm is striking, and we had postulated that this was likely to largely result from protection conferred to recombinant enzymes by biofilm's extracellular matrix. SILAC (stable isotopic labelled amino acids in cell cultures), and in particular dynamic SILAC, in which pulses of different isotopically labelled amino acids are administered to cells over a time course, has been used to follow the fate of proteins. To explore within our spin coated biofilm, whether the recombinant enzyme's longevity might be in part due to its regeneration, we introduced pulses of isotopically labelled lysine and phenylalanine into medium overlaying the biofilm and followed their incorporation over the course of biofilm development.

RESULTS: Through SILAC analysis, we reveal that constant and complete regeneration of recombinant enzymes occurs within spin coated biofilms. The striking catalytic longevity within the biofilm results from more than just simple protection of active enzyme by the biofilm and its associated extracellular matrix. The replenishment of recombinant enzyme is likely to contribute significantly to the catalytic longevity observed for the engineered biofilm system.

CONCLUSIONS: Here we provide the first evidence of a recombinant enzyme's regeneration in an engineered biofilm. The recombinant enzyme was constantly replenished over time as evidenced by dynamic SILAC, which suggests that the engineered E. coli biofilms are highly metabolically active, having a not inconsiderable energetic demand. The constant renewal of recombinant enzyme highlights the attractive possibility of utilising this biofilm system as a dynamic platform into which enzymes of interest can be introduced in a "plug-and-play" fashion and potentially be controlled through promoter switching for production of a series of desired fine chemicals.}, } @article {pmid27573013, year = {2016}, author = {Heussler, GE and Miller, JL and Price, CE and Collins, AJ and O'Toole, GA}, title = {Requirements for Pseudomonas aeruginosa Type I-F CRISPR-Cas Adaptation Determined Using a Biofilm Enrichment Assay.}, journal = {Journal of bacteriology}, volume = {198}, number = {22}, pages = {3080-3090}, pmid = {27573013}, issn = {1098-5530}, support = {R37 AI083256/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics ; Bacteriophages/genetics/pathogenicity ; *Biofilms ; CRISPR-Associated Proteins/genetics ; CRISPR-Cas Systems/*genetics ; Clustered Regularly Interspaced Short Palindromic Repeats/*genetics ; Escherichia coli/genetics ; Pseudomonas aeruginosa/*genetics/virology ; }, abstract = {UNLABELLED: CRISPR (clustered regularly interspaced short palindromic repeat)-Cas (CRISPR-associated protein) systems are diverse and found in many archaea and bacteria. These systems have mainly been characterized as adaptive immune systems able to protect against invading mobile genetic elements, including viruses. The first step in this protection is acquisition of spacer sequences from the invader DNA and incorporation of those sequences into the CRISPR array, termed CRISPR adaptation. Progress in understanding the mechanisms and requirements of CRISPR adaptation has largely been accomplished using overexpression of cas genes or plasmid loss assays; little work has focused on endogenous CRISPR-acquired immunity from viral predation. Here, we developed a new biofilm-based assay system to enrich for Pseudomonas aeruginosa strains with new spacer acquisition. We used this assay to demonstrate that P. aeruginosa rapidly acquires spacers protective against DMS3vir, an engineered lytic variant of the Mu-like bacteriophage DMS3, through primed CRISPR adaptation from spacers present in the native CRISPR2 array. We found that for the P. aeruginosa type I-F system, the cas1 gene is required for CRISPR adaptation, recG contributes to (but is not required for) primed CRISPR adaptation, recD is dispensable for primed CRISPR adaptation, and finally, the ability of a putative priming spacer to prime can vary considerably depending on the specific sequences of the spacer.

IMPORTANCE: Our understanding of CRISPR adaptation has expanded largely through experiments in type I CRISPR systems using plasmid loss assays, mutants of Escherichia coli, or cas1-cas2 overexpression systems, but there has been little focus on studying the adaptation of endogenous systems protecting against a lytic bacteriophage. Here we describe a biofilm system that allows P. aeruginosa to rapidly gain spacers protective against a lytic bacteriophage. This approach has allowed us to probe the requirements for CRISPR adaptation in the endogenous type I-F system of P. aeruginosa Our data suggest that CRISPR-acquired immunity in a biofilm may be one reason that many P. aeruginosa strains maintain a CRISPR-Cas system.}, } @article {pmid27768533, year = {2017}, author = {Wang, S and Pu, Y and Wei, C}, title = {COD and nitrogen removal and microbial communities in a novel waterfall biofilm reactor operated at different COD/TN ratios.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {52}, number = {2}, pages = {99-105}, doi = {10.1080/10934529.2016.1237115}, pmid = {27768533}, issn = {1532-4117}, mesh = {Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification ; Humans ; Nitrogen/*chemistry ; Wastewater ; *Water Microbiology ; Water Purification/methods ; }, abstract = {The aim of this study was to characterize the pollutant removal efficiency and the microbial communities that arose in a newly designed waterfall biofilm reactor (WFBR) at different chemical oxygen demand/total nitrogen (COD/TN) ratios. The reactor was operated continuously for 28 days at different COD/TN ratios, and its efficiency was evaluated. Results showed that as the thickness of the biofilm increased, the structure of the biofilm encouraged anaerobic-aerobic, anoxic-anaerobic, and fully anaerobic conditions in one reactor. The COD/TN ratios used had a significant effect on the removal of COD and nitrogen components. At a COD/TN ratio of 14, the ammonium nitrogen removal efficiency reached its highest value (99%), but the COD removal efficiency remained at approximately 90%. High-throughput sequencing revealed that the highest community diversity and richness were seen at a COD/TN ratio of 18, and the major phyla were Proteobacteria (average abundance of 47%), Actinobacteria (24%), and Bacteroidetes (13%). As the COD/TN ratios increased from 7 to 18, the abundance of Proteobacteria gradually increased from 25% to 68%. These results could provide important guidance for the design of new wastewater treatment systems and also enrich our theoretical understanding of microbial ecology.}, } @article {pmid27768058, year = {2016}, author = {Bucher, T and Kartvelishvily, E and Kolodkin-Gal, I}, title = {Methodologies for Studying B. subtilis Biofilms as a Model for Characterizing Small Molecule Biofilm Inhibitors.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {116}, pages = {}, pmid = {27768058}, issn = {1940-087X}, mesh = {Amino Acids ; Bacillus subtilis ; *Biofilms ; Microscopy, Electron, Scanning ; Plankton ; }, abstract = {This work assesses different methodologies to study the impact of small molecule biofilm inhibitors, such as D-amino acids, on the development and resilience of Bacillus subtilis biofilms. First, methods are presented that select for small molecule inhibitors with biofilm-specific targets in order to separate the effect of the small molecule inhibitors on planktonic growth from their effect on biofilm formation. Next, we focus on how inoculation conditions affect the sensitivity of multicellular, floating B. subtilis cultures to small molecule inhibitors. The results suggest that discrepancies in the reported effects of such inhibitors such as D-amino acids are due to inconsistent pre-culture conditions. Furthermore, a recently developed protocol is described for evaluating the contribution of small molecule treatments towards biofilm resistance to antibacterial substances. Lastly, scanning electron microscopy (SEM) techniques are presented to analyze the three-dimensional spatial arrangement of cells and their surrounding extracellular matrix in a B. subtilis biofilm. SEM facilitates insight into the three-dimensional biofilm architecture and the matrix texture. A combination of the methods described here can greatly assist the study of biofilm development in the presence and absence of biofilm inhibitors, and shed light on the mechanism of action of these inhibitors.}, } @article {pmid27765942, year = {2016}, author = {Rajendran, R and May, A and Sherry, L and Kean, R and Williams, C and Jones, BL and Burgess, KV and Heringa, J and Abeln, S and Brandt, BW and Munro, CA and Ramage, G}, title = {Integrating Candida albicans metabolism with biofilm heterogeneity by transcriptome mapping.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {35436}, pmid = {27765942}, issn = {2045-2322}, support = {097377//Wellcome Trust/United Kingdom ; MR/N006364/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Algorithms ; Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Candida albicans/genetics/*metabolism ; Gene Expression Profiling ; Genes, Fungal ; Phenotype ; Sequence Analysis, DNA ; Sequence Analysis, RNA ; *Transcriptome ; }, abstract = {Candida albicans biofilm formation is an important virulence factor in the pathogenesis of disease, a characteristic which has been shown to be heterogeneous in clinical isolates. Using an unbiased computational approach we investigated the central metabolic pathways driving biofilm heterogeneity. Transcripts from high (HBF) and low (LBF) biofilm forming isolates were analysed by RNA sequencing, with 6312 genes identified to be expressed in these two phenotypes. With a dedicated computational approach we identified and validated a significantly differentially expressed subnetwork of genes associated with these biofilm phenotypes. Our analysis revealed amino acid metabolism, such as arginine, proline, aspartate and glutamate metabolism, were predominantly upregulated in the HBF phenotype. On the contrary, purine, starch and sucrose metabolism was generally upregulated in the LBF phenotype. The aspartate aminotransferase gene AAT1 was found to be a common member of these amino acid pathways and significantly upregulated in the HBF phenotype. Pharmacological inhibition of AAT1 enzyme activity significantly reduced biofilm formation in a dose-dependent manner. Collectively, these findings provide evidence that biofilm phenotype is associated with differential regulation of metabolic pathways. Understanding and targeting such pathways, such as amino acid metabolism, is potentially useful for developing diagnostics and new antifungals to treat biofilm-based infections.}, } @article {pmid27592071, year = {2016}, author = {Lamas, A and Miranda, JM and Vázquez, B and Cepeda, A and Franco, CM}, title = {Biofilm formation, phenotypic production of cellulose and gene expression in Salmonella enterica decrease under anaerobic conditions.}, journal = {International journal of food microbiology}, volume = {238}, number = {}, pages = {63-67}, doi = {10.1016/j.ijfoodmicro.2016.08.043}, pmid = {27592071}, issn = {1879-3460}, mesh = {*Anaerobiosis ; Bacterial Proteins/*genetics ; *Biofilms ; Cellulose/*genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Salmonella enterica/*enzymology/*genetics ; }, abstract = {Salmonella enterica subsp. enterica is one of the main food-borne pathogens. This microorganism combines an aerobic life outside the host with an anaerobic life within the host. One of the main concerns related to S. enterica is biofilm formation and cellulose production. In this study, biofilm formation, morphotype, cellulose production and transcription of biofilm and quorum sensing-related genes of 11 S. enterica strains were tested under three different conditions: aerobiosis, microaerobiosis, and anaerobiosis. The results showed an influence of oxygen levels on biofilm production. Biofilm formation was significantly higher (P<0.05) in aerobiosis than in microaerobiosis and anaerobiosis. Cellulose production and RDAR (red, dry, and rough) were expressed only in aerobiosis. In microaerobiosis, the strains expressed the SAW (smooth and white) morphotype, while in anaerobiosis the colonies appeared small and red. The expression of genes involved in cellulose synthesis (csgD and adrA) and quorum sensing (sdiA and luxS) was reduced in microaerobiosis and anaerobiosis in all S. enterica strains tested. This gene expression levels were less reduced in S. Typhimurium and S. Enteritidis compared to the tested serotypes. There was a relationship between the expression of biofilm and quorum sensing-related genes. Thus, the results from this study indicate that biofilm formation and cellulose production are highly influenced by atmospheric conditions. This must be taken into account as contamination with these bacteria can occur during food processing under vacuum or modified atmospheres.}, } @article {pmid27591384, year = {2016}, author = {Nostro, A and Guerrini, A and Marino, A and Tacchini, M and Di Giulio, M and Grandini, A and Akin, M and Cellini, L and Bisignano, G and Saraçoğlu, HT}, title = {In vitro activity of plant extracts against biofilm-producing food-related bacteria.}, journal = {International journal of food microbiology}, volume = {238}, number = {}, pages = {33-39}, doi = {10.1016/j.ijfoodmicro.2016.08.024}, pmid = {27591384}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/pharmacology ; Antioxidants/isolation & purification/pharmacology ; Biofilms/*drug effects ; *Food Microbiology ; Magnoliopsida/*chemistry ; Methanol/chemistry ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Pseudomonas aeruginosa/*drug effects ; Staphylococcus aureus/*drug effects ; }, abstract = {The identification of effective antimicrobial agents also active on biofilms is a topic of crucial importance in food and industrial environment. For that purpose methanol extracts of Turkish plants, Ficus carica L., Juglans regia L., Olea europaea L., Punica granatum L. and Rhus coriaria L., were investigated. Among the extracts, P. granatum L. and R. coriaria L. showed the best antibacterial activity with minimum inhibitory concentrations (MIC) of 78-625μg/ml for Listeria monocytogenes and Staphylococcus aureus and 312-1250μg/ml for Escherichia coli and Pseudomonas aeruginosa. SubMICs produced a significant biofilm inhibition equal to 80-60% for L. monocytogenes and 90-80% for S. aureus. The extracts showed also the highest polyphenol content and the strongest antioxidant activity. Bioassay-guided and HPLC procedures demonstrated the presence of apigenin 4'-O-β-glucoside in P. granatum L. and myricetrin and quercitrin in R. coriaria L. Antigenotoxicity of plant extracts was also observed The present findings promote the value-adding of P. granatum L. and R. coriaria L. leaves as natural antimicrobial/antioxidant agents for control of food-related bacterial biofilms.}, } @article {pmid27764679, year = {2017}, author = {Qiu, W and Ren, B and Dai, H and Zhang, L and Zhang, Q and Zhou, X and Li, Y}, title = {Clotrimazole and econazole inhibit Streptococcus mutans biofilm and virulence in vitro.}, journal = {Archives of oral biology}, volume = {73}, number = {}, pages = {113-120}, doi = {10.1016/j.archoralbio.2016.10.011}, pmid = {27764679}, issn = {1879-1506}, mesh = {Anti-Bacterial Agents/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Clotrimazole/*pharmacology ; Econazole/*pharmacology ; Humans ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*drug effects/*pathogenicity ; Virulence Factors ; }, abstract = {OBJECTIVE: The aim of this study was to determine the inhibitory effect of eight antifungal drugs on S. mutans growth, biofilm formation and virulence factors.

METHODS: The actions of antifungal drugs on S. mutans were determined by recovery plates and survival kinetic curves. Biofilms were observed by scanning electron microscopy and the viable cells were recovered on BHI plates, meanwhile biofilms were stained by BacLight live/dead kit to investigate the biofilm viability. Bacteria/extracellular polysaccharides staining assays were performed to determine the EPS production of S. mutans biofilms. Acidogenicity and acidurity of S. mutans were determined using pH drop and acid tolerance assays, and the expression of ldh gene was evaluated using qPCR.

RESULTS: We found that clotrimazole (CTR) and econazole (ECO) showed antibacterial activities on S. mutans UA159 and S. mutans clinical isolates at 12.5 and 25mg/L, respectively. CTR and ECO could also inhibit S. mutans biofilm formation and reduce the viability of preformed biofilm. CTR and ECO affected the live/dead ratio and the EPS/bacteria ratio of S. mutans biofilms. CTR and ECO also inhibited the pH drop, lactate acid production, and acid tolerance. The abilities of CTR and ECO to inhibit S. mutans ldh expression were also confirmed.

CONCLUSIONS: We found that two antifungal azoles, CTR and ECO, had the abilities to inhibit the growth and biofilm formation of S. mutans and more importantly, they could also inhibit the virulence factors of S. mutans.}, } @article {pmid27763775, year = {2016}, author = {Obaid, NA and Tristram, S and Narkowicz, CK and Jacobson, GA}, title = {Reliability of Haemophilus influenzae biofilm measurement via static method, and determinants of in vitro biofilm production.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {12}, pages = {1013-1020}, doi = {10.1139/cjm-2016-0228}, pmid = {27763775}, issn = {1480-3275}, mesh = {Biofilms/*growth & development ; Cryopreservation ; Haemophilus Infections/*microbiology ; Haemophilus influenzae/*physiology ; Humans ; Reproducibility of Results ; }, abstract = {Information is lacking regarding the precision of microtitre plate (MTP) assays used to measure biofilm. This study investigated the precision of an MTP assay to measure biofilm production by nontypeable Haemophilus influenzae (NTHi) and the effects of frozen storage and inoculation technique on biofilm production. The density of bacterial final growth was determined by absorbance after 18-20 h incubation, and biofilm production was then measured by absorbance after crystal violet staining. Biofilm formation was categorised as high and low for each strain. For the high biofilm producing strains of NTHi, interday reproducibility of NTHi biofilm formation measured using the MTP assay was excellent and met the acceptance criteria, but higher variability was observed in low biofilm producers. Method of inoculum preparation was a determinant of biofilm formation with inoculum prepared directly from solid media showing increased biofilm production for at least one of the high producing strains. In general, storage of NTHi cultures at -80 °C for up to 48 weeks did not have any major effect on their ability to produce biofilm.}, } @article {pmid27762637, year = {2016}, author = {Wang, X and Cheng, H and Lu, M and Fang, Y and Jiao, Y and Li, W and Zhao, G and Wang, S}, title = {Dextranase from Arthrobacter oxydans KQ11-1 inhibits biofilm formation by polysaccharide hydrolysis.}, journal = {Biofouling}, volume = {32}, number = {10}, pages = {1223-1233}, doi = {10.1080/08927014.2016.1239722}, pmid = {27762637}, issn = {1029-2454}, mesh = {Arthrobacter/*enzymology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Dental Plaque/microbiology/*prevention & control ; Dextranase/chemistry/genetics/*pharmacology ; Escherichia coli/drug effects ; Hydrolysis ; Polysaccharides/*chemistry ; Recombinant Proteins ; Streptococcus mutans/drug effects/*physiology ; Temperature ; }, abstract = {Dental plaque is a biofilm of water-soluble and water-insoluble polysaccharides, produced primarily by Streptococcus mutans. Dextranase can inhibit biofilm formation. Here, a dextranase gene from the marine microorganism Arthrobacter oxydans KQ11-1 is described, and cloned and expressed using E. coli DH5α competent cells. The recombinant enzyme was then purified and its properties were characterized. The optimal temperature and pH were determined to be 60°C and 6.5, respectively. High-performance liquid chromatography data show that the final hydrolysis products were glucose, maltose, maltotriose, and maltotetraose. Thus, dextranase can inhibit the adhesive ability of S. mutans. The minimum biofilm inhibition and reduction concentrations (MBIC50 and MBRC50) of dextranase were 2 U ml[-1] and 5 U ml[-1], respectively. Scanning electron microscopy and confocal laser scanning microscope (CLSM) observations confirmed that dextranase inhibited biofilm formation and removed previously formed biofilms.}, } @article {pmid27761465, year = {2016}, author = {Gowrishankar, S and Kamaladevi, A and Balamurugan, K and Pandian, SK}, title = {In Vitro and In Vivo Biofilm Characterization of Methicillin-Resistant Staphylococcus aureus from Patients Associated with Pharyngitis Infection.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {1289157}, pmid = {27761465}, issn = {2314-6141}, mesh = {Bacterial Adhesion/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Female ; Humans ; Male ; *Methicillin-Resistant Staphylococcus aureus/isolation & purification/physiology ; *Pharyngitis/genetics/microbiology ; Staphylococcal Infections/*genetics ; }, abstract = {The present investigation was deliberately aimed at evaluating the biofilm-forming ability of 63 clinical MRSA isolates recovered from pharyngitis patients through different phenotypic assays. The molecular detection of adhesion (icaA/icaD/icaB/icaC), adhesins (fnbA/fnbB, clfA, and cna), staphylococcal accessory regulator (sarA), and α-toxin (hla) genes was done by employing polymerase chain reaction (PCR). Out of 63 isolates, 49 (77.8%) were found slime positive by the Congo red agar (CRA) method and 44 (69.8%) as biofilm positive by the quantitative microtitre plate assays. The results of MATH assay showed that most of the test pathogens are hydrophilic in nature. The molecular investigation of biofilm-associated genes revealed that 84.13% (n = 53) of isolates were found positive for icaADBC genes. The fnbA and fnbB genes were present in 49 (77.8%) and 51 (81%) MRSA isolates, respectively. In addition, 58.7% (n = 37), 73% (n = 46), and 69.8% (n = 44) of the isolates harboured the clfA, cna, and hla genes, respectively. Further, nearly 81% (n = 51) of the isolates were found positive for the gene sarA and all the ica negative isolates were also negative for the gene. Furthermore, the results of in vivo adherence assay unveiled the factual commonness in the in vitro adherence method.}, } @article {pmid27758704, year = {2017}, author = {Chung, PY}, title = {Plant-derived Compounds as Potential Source of Novel Anti-Biofilm Agents Against Pseudomonas aeruginosa.}, journal = {Current drug targets}, volume = {18}, number = {4}, pages = {414-420}, doi = {10.2174/1389450117666161019102025}, pmid = {27758704}, issn = {1873-5592}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/drug effects ; Cystic Fibrosis/complications ; Humans ; Plant Extracts/*pharmacology/therapeutic use ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {Pseudomonas aeruginosa is the most common Gram-negative bacterium associated with nosocomial and life-threatening chronic infections in cystic fibrosis patients. This pathogen is wellknown for its ability to attach to surfaces of indwelling medical devices to form biofilms, which consist of a regular array of extracellular polymers. Tenaciously bound to the surface of devices and inherently resilient to antibiotic treatment, P. aeruginosa poses a serious threat in clinical medicine and contributes to the persistence of chronic infections. Studies on microbial biofilms in the past decade involved mainly the understanding of environment signals, genetic elements and molecular mechanisms in biofilm formation, tolerance and dispersal. The knowledge obtained from the studies of these mechanisms is crucial in the establishment of strategies to eradicate or to prevent biofilm formation. Currently, biofilm infections are usually treated with combinations of antibiotics and surgical removal, in addition to frequent replacement of the infected device. More recently, specific natural sources have been identified as antibiofilm agents against this pathogen. This review will highlight the recent progress made by plant-derived compounds against P. aeruginosa biofilm infections in both in vitro or in vivo models.}, } @article {pmid27757936, year = {2017}, author = {Romanò, CL and Romanò, D and Morelli, I and Drago, L}, title = {The Concept of Biofilm-Related Implant Malfunction and "Low-Grade Infection".}, journal = {Advances in experimental medicine and biology}, volume = {971}, number = {}, pages = {1-13}, doi = {10.1007/5584_2016_158}, pmid = {27757936}, issn = {0065-2598}, mesh = {Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Humans ; Inflammation/microbiology ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*microbiology ; }, abstract = {Biofilms have a tremendous impact on industrial machines working in moist environments, while in biological systems their effect is further complicated by the host's response.Implant-related infections are a complex process, starting with bacterial adhesion and biofilm formation, followed by the variable interaction between host, implant, microorganisms and their by-products. Depending on the balance of these factors, different clinical presentations are observed, which may eventually, at times, shift from one into the other.-"Implant malfunction" displays only mild clinical signs/symptoms - light pain and/or slight soft tissue contracture or functional impairment - with negative infection/inflammatory markers; it requires prolonged cultures, antibiofilm and eventually genomic investigations for pathogen detection;-"Low-grade infection" features recurrent or persistent pain and/or soft tissue contracture with various functional impairment and mixed positive/negative markers of infection/inflammation; pathogen identification requires prolonged cultures and antibiofilm techniques;-"High-grade infection" displays classical signs/symptoms of infection/inflammation with positive tests; pathogen identification is often possible with traditional microbiological techniques, but is better achieved with prolonged cultures and antibiofilm processing.Understanding biofilms-related clinical presentations is crucial for physicians, to implement the best diagnostic and therapeutic measures, and for regulatory bodies, to define the evaluation process of technologies aimed at reducing implants' malfunctions and infections, like anti-adhesive and antibiofilm coatings, that should be regulated as (part of) medical devices, requiring a suitable post-marketing surveillance.Only an effective antibiofilm-targeted approach from all players will hopefully allow the medical community to mitigate the current unacceptable social and economical burden of implant-related infections and malfunctions.}, } @article {pmid27757550, year = {2017}, author = {Schmidt, JC and Astasov-Frauenhoffer, M and Waltimo, T and Weiger, R and Walter, C}, title = {Efficacy of various side-to-side toothbrushes and impact of brushing parameters on noncontact biofilm removal in an interdental space model.}, journal = {Clinical oral investigations}, volume = {21}, number = {5}, pages = {1565-1577}, pmid = {27757550}, issn = {1436-3771}, mesh = {*Biofilms ; Dental Plaque/microbiology ; Dental Plaque Index ; Fusobacterium nucleatum ; In Vitro Techniques ; Models, Dental ; Porphyromonas gingivalis ; Streptococcus sanguis ; Toothbrushing/*instrumentation ; }, abstract = {OBJECTIVES: The objective of this study was to evaluate the efficacy of four different side-to-side toothbrushes and the impact of various brushing parameters on noncontact biofilm removal in an adjustable interdental space model.

MATERIALS AND METHODS: A three-species biofilm, consisting of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus sanguinis, was formed in vitro on protein-coated titanium disks using a flow chamber combined with a static biofilm growth model. Subsequently, the biofilm-coated disks were exposed to four different powered toothbrushes (A, B, C, D). The parameters distance (0 and 1 mm), brushing time (2, 4, and 6 s), interdental space width (1, 2, and 3 mm), and toothbrush angulation (45° and 90°) were tested. The biofilm volumes were determined using volumetric analyses with confocal laser scanning microscope (Zeiss LSM700) images and Imaris version 7.7.2 software.

RESULTS: The median percentages of simulated interdental biofilm reduction by the tested toothbrushes ranged from 7 to 64 %. The abilities of the analyzed toothbrushes to reduce the in vitro biofilm differed significantly (p < 0.05). Three of the tested toothbrushes (A, B, C) were able to significantly reduce a simulated interdental biofilm by noncontact brushing (p ≤ 0.005). The brushing parameters and their combinations tested in the experiments revealed only minor effects on in vitro interdental biofilm reduction (p > 0.05).

CONCLUSIONS: A three-species in vitro biofilm could be altered by noncontact brushing with toothbrushes A, B, and C in an artificial interdental space model.

CLINICAL RELEVANCE: Certain side-to-side toothbrushes demonstrate in vitro a high efficacy in interdental biofilm removal without bristle-to-biofilm contact.}, } @article {pmid27756305, year = {2016}, author = {Ahmad, I and Rouf, SF and Sun, L and Cimdins, A and Shafeeq, S and Le Guyon, S and Schottkowski, M and Rhen, M and Römling, U}, title = {BcsZ inhibits biofilm phenotypes and promotes virulence by blocking cellulose production in Salmonella enterica serovar Typhimurium.}, journal = {Microbial cell factories}, volume = {15}, number = {1}, pages = {177}, pmid = {27756305}, issn = {1475-2859}, mesh = {*Biofilms ; Cellulose/antagonists & inhibitors/*biosynthesis ; Glucosyltransferases/*metabolism ; Phenotype ; Salmonella typhimurium/enzymology/genetics/metabolism/*physiology ; }, abstract = {BACKGROUND: Cellulose, a 1,4 beta-glucan polysaccharide, is produced by a variety of organisms including bacteria. Although the production of cellulose has a high biological, ecological and economical impact, regulatory mechanisms of cellulose biosynthesis are mostly unknown. Family eight cellulases are regularly associated with cellulose biosynthesis operons in bacteria; however, their function is poorly characterized. In this study, we analysed the role of the cellulase BcsZ encoded by the bcsABZC cellulose biosynthesis operon of Salmonella enterica serovar Typhimurium (S. Typhimurium) in biofilm related behavior. We also investigated the involvement of BcsZ in pathogenesis of S. Typhimurium including a murine typhoid fever infection model.

RESULT: In S. Typhimurium, cellulase BcsZ with a putative periplasmic location negatively regulates cellulose biosynthesis. Moreover, as assessed with a non-polar mutant, BcsZ affects cellulose-associated phenotypes such as the rdar biofilm morphotype, cell clumping, biofilm formation, pellicle formation and flagella-dependent motility. Strikingly, although upregulation of cellulose biosynthesis was not observed on agar plate medium at 37 °C, BcsZ is required for efficient pathogen-host interaction. Key virulence phenotypes of S. Typhimurium such as invasion of epithelial cells and proliferation in macrophages were positively regulated by BcsZ. Further on, a bcsZ mutant was outcompeted by the wild type in organ colonization in the murine typhoid fever infection model. Selected phenotypes were relieved upon deletion of the cellulose synthase BcsA and/or the central biofilm activator CsgD.

CONCLUSION: Although the protein scaffold has an additional physiological role, our findings indicate that the catalytic activity of BcsZ effectively downregulates CsgD activated cellulose biosynthesis. Repression of cellulose production by BcsZ subsequently enables Salmonella to efficiently colonize the host.}, } @article {pmid27756240, year = {2016}, author = {Günther, F and Merle, U and Frank, U and Gaida, MM and Mutters, NT}, title = {Pseudobacteremia outbreak of biofilm-forming Achromobacter xylosoxidans - environmental transmission.}, journal = {BMC infectious diseases}, volume = {16}, number = {1}, pages = {584}, pmid = {27756240}, issn = {1471-2334}, mesh = {Achromobacter denitrificans/isolation & purification/*pathogenicity/physiology ; Biofilms ; Disease Outbreaks ; Disinfectants/pharmacology ; Germany/epidemiology ; Gram-Negative Bacterial Infections/*epidemiology ; Hospitals ; Humans ; Random Amplified Polymorphic DNA Technique ; Retrospective Studies ; }, abstract = {BACKGROUND: Achromobacter xylosoxidans (AX) is known for intrinsic resistance to disinfectants. Our laboratory routine surveillance system detected an unexpected rise in AX bloodstream infections in a 2200-bed hospital. An epidemiological investigation was conducted to find the source and disrupt further transmission.

METHODS: Outbreak cases were defined as patients with at least one positive blood culture positive for AX from May 2014 to May 2015. Medical records were reviewed, affected wards, as well as the microbiology laboratory were audited. Additionally, microbiologic culture and biofilm staining for suspected antiseptic reusable tissue dispensers were performed, and isolated AX strains were typed using RAPD PCR and PFGE.

RESULTS: During the outbreak period, AX were isolated from blood cultures from 26 patients. The retrospective cohort study did not reveal common risk factors. The clinical features of the case patients suggested a pseudobacteremia. The reusable tissue dispensers containing Incidin® Plus solution product were found to be contaminated with biofilm-forming AX. Typing of the isolates revealed that blood culture isolates were identical with the strains found in the dispensers.

CONCLUSIONS: After changing the usage of the product to single-use and educating staff, the outbreak was terminated. Contamination of dispensers occurred due to insufficient reprocessing, since biofilm disrupting steps were not included in the process.}, } @article {pmid27756222, year = {2016}, author = {González-Ramírez, AI and Ramírez-Granillo, A and Medina-Canales, MG and Rodríguez-Tovar, AV and Martínez-Rivera, MA}, title = {Analysis and description of the stages of Aspergillus fumigatus biofilm formation using scanning electron microscopy.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {243}, pmid = {27756222}, issn = {1471-2180}, mesh = {Aspergillosis/microbiology ; Aspergillus fumigatus/*cytology/growth & development/isolation & purification/*physiology ; Biofilms/*growth & development ; Culture Media ; Extracellular Matrix/microbiology/physiology ; Fungal Proteins/analysis/genetics ; Germination/physiology ; Humans ; Hyphae/cytology/growth & development ; Mexico ; Microscopy, Electron, Scanning/*methods ; Soil Microbiology ; Spores, Fungal/cytology/growth & development ; Temperature ; }, abstract = {BACKGROUND: Biofilms are a highly structured consortia of microorganisms that adhere to a substrate and are encased within an extracellular matrix (ECM) that is produced by the organisms themselves. Aspergillus fumigatus is a biotechnological fungus that has a medical and phytopathogenic significance, and its biofilm occurs in both natural and artificial environments; therefore, studies on the stages observed in biofilm formation are of great significance due to the limited knowledge that exists on this specific topic and because there are multiple applications that are being carried out.

RESULTS: Growth curves were obtained from the soil and clinical isolates of the A. fumigatus biofilm formation. The optimal conditions for both of the isolates were inocula of 1 × 10[6] conidia/mL, incubated at 28 °C during 24 h; these showed stages similar to those described in classic microbial growth: the lag, exponential, and stationary phases. However, the biofilms formed at 37 °C were uneven. The A. fumigatus biofilm was similar regardless of the isolation source, but differences were presented according to the incubation temperature. The biofilm stages included the following: 1) adhesion to the plate surface (4 h), cell co-aggregation and exopolymeric substance (EPS) production; 2) conidial germination into hyphae (8-12 h), development, hyphal elongation, and expansion with channel formation (16-20 h); and 3) biofilm maturation as follows: mycelia development, hyphal layering networks, and channels formation, and high structural arrangement of the mycelia that included hyphal anastomosis and an extensive production of ECM (24 h); the ECM covered, surrounded and strengthened the mycelial arrangements, particular at 37 °C. In the clinical isolate, irregular fungal structures, such as microhyphae that are short and slender hyphae, occurred; 4) In cell dispersion, the soil isolate exhibited higher conidia than the clinical isolate, which had the capacity to germinate and generate new mycelia growth (24 h). In addition, we present images on the biofilm's structural arrangement and chemical composition using fluorochromes to detect metabolic activity (FUNI) and mark molecules, such as chitin, DNA, mannose, glucose and proteins.

CONCLUSIONS: To our knowledge, this is the first time that, in vitro, scanning electronic microscopy (SEM) images of the stages of A. fumigatus biofilm formation have been presented with a particular emphasis on the high hyphal organization and in diverse ECM to observe biofilm maturation.}, } @article {pmid27703012, year = {2016}, author = {Valiente, E and Bouché, L and Hitchen, P and Faulds-Pain, A and Songane, M and Dawson, LF and Donahue, E and Stabler, RA and Panico, M and Morris, HR and Bajaj-Elliott, M and Logan, SM and Dell, A and Wren, BW}, title = {Role of Glycosyltransferases Modifying Type B Flagellin of Emerging Hypervirulent Clostridium difficile Lineages and Their Impact on Motility and Biofilm Formation.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {49}, pages = {25450-25461}, pmid = {27703012}, issn = {1083-351X}, support = {BB/F008309/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/D521849/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 102979/Z/13/Z//Wellcome Trust/United Kingdom ; G1000214/MRC_/Medical Research Council/United Kingdom ; MR/K000551/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Caco-2 Cells ; Clostridioides difficile/pathogenicity/*physiology ; Flagellin/genetics/*metabolism ; Glycosylation ; Glycosyltransferases/*metabolism ; Humans ; Toll-Like Receptor 5/metabolism ; }, abstract = {Clostridium difficile is the principal cause of nosocomial infectious diarrhea worldwide. The pathogen modifies its flagellin with either a type A or type B O-linked glycosylation system, which has a contributory role in pathogenesis. We study the functional role of glycosyltransferases modifying type B flagellin in the 023 and 027 hypervirulent C. difficile lineages by mutagenesis of five putative glycosyltransferases and biosynthetic genes. We reveal their roles in the biosynthesis of the flagellin glycan chain and demonstrate that flagellar post-translational modification affects motility and adhesion-related bacterial properties of these strains. We show that the glycosyltransferases 1 and 2 (GT1 and GT2) are responsible for the sequential addition of a GlcNAc and two rhamnoses, respectively, and that GT3 is associated with the incorporation of a novel sulfonated peptidyl-amido sugar moiety whose structure is reported in our accompanying paper (Bouché, L., Panico, M., Hitchen, P., Binet, D., Sastre, F., Faulds-Pain, A., Valiente, E., Vinogradov, E., Aubry, A., Fulton, K., Twine, S., Logan, S. M., Wren, B. W., Dell, A., and Morris, H. R. (2016) J. Biol. Chem. 291, 25439-25449). GT2 is also responsible for methylation of the rhamnoses. Whereas type B modification is not required for flagellar assembly, some mutations that result in truncation or abolition of the glycan reduce bacterial motility and promote autoaggregation and biofilm formation. The complete lack of flagellin modification also significantly reduces adhesion of C. difficile to Caco-2 intestinal epithelial cells but does not affect activation of human TLR5. Our study advances our understanding of the genes involved in flagellar glycosylation and their biological roles in emerging hypervirulent C. difficile strains.}, } @article {pmid27592437, year = {2016}, author = {Aslantaş, Ö and Demir, C}, title = {Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases.}, journal = {Journal of dairy science}, volume = {99}, number = {11}, pages = {8607-8613}, doi = {10.3168/jds.2016-11310}, pmid = {27592437}, issn = {1525-3198}, mesh = {Adhesins, Bacterial/genetics/metabolism ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects ; Cattle ; Coagulase/genetics/metabolism ; DNA, Bacterial/genetics ; *Drug Resistance, Multiple, Bacterial ; Erythromycin/pharmacology ; Female ; Mastitis, Bovine/drug therapy/*microbiology ; Methicillin-Resistant Staphylococcus aureus/genetics/growth & development/*isolation & purification ; Methyltransferases/genetics/metabolism ; Microbial Sensitivity Tests ; Staphylococcal Infections/diagnosis/drug therapy/veterinary ; Tetracycline/pharmacology ; beta-Lactams/pharmacology ; }, abstract = {A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to β-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate.}, } @article {pmid27562471, year = {2016}, author = {Hou, J and You, G and Xu, Y and Wang, C and Wang, P and Miao, L and Li, Y and Ao, Y and Lv, B and Yang, Y}, title = {Long-term effects of CuO nanoparticles on the surface physicochemical properties of biofilms in a sequencing batch biofilm reactor.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {22}, pages = {9629-9639}, doi = {10.1007/s00253-016-7799-7}, pmid = {27562471}, issn = {1432-0614}, mesh = {Biofilms/*drug effects ; Bioreactors/*microbiology ; *Chemical Phenomena ; Copper/*metabolism ; Nanoparticles/*metabolism ; Polysaccharides/analysis ; Proteins/analysis ; Surface Properties/*drug effects ; }, abstract = {In this study, we examined the long-term effects of copper oxide nanoparticles (CuO NPs) on the production and properties of EPS and the resulting variations in surface physicochemical characteristics of biofilms in a sequencing batch biofilm reactor. After exposure to 50 mg/L CuO NPs for 45 days, the protein (PRO) and polysaccharide (PS) contents in loosely bound EPS (LB-EPS) decreased as the production of LB-EPS decreased from 34.4 to 30 mg TOC/g EPS. However, the production of tightly bound EPS (TB-EPS) increased by 16.47 % as the PRO and PS contents increased. The content of humic-like substances (HS) increased significantly, becoming the predominant constituent in EPS with the presence of 50 mg/L CuO NPs. Furthermore, the results of three-dimensional excitation-emission fluorescence spectra confirmed the various changes in terms of the LB-EPS and TB-EPS contents after exposure to CuO NPs. Fourier transform infrared spectroscopy showed that the -OH and -NH2 groups of proteins in EPS were involved in the reaction with CuO NPs. Moreover, the chronic exposure to CuO NPs induced a negative impact on the flocculating efficiency of EPS and on the hydrophobicity and aggregation ability of microbial cells. The PRO/PS ratios of different EPS fractions were consistent with their hydrophobicities (R [2] >0.98) and bioflocculating efficiencies (R [2] >0.95); however, there was no correlation with aggregation ability. Additionally, the presence of bovine serum albumin (BSA) prevented the physical contact between CuO NPs and EPS as a result of NP aggregation and electrostatic repulsion.}, } @article {pmid27448729, year = {2016}, author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L and Lv, B and Yang, Y}, title = {Influence of CeO2 NPs on biological phosphorus removal and bacterial community shifts in a sequencing batch biofilm reactor with the differential effects of molecular oxygen.}, journal = {Environmental research}, volume = {151}, number = {}, pages = {21-29}, doi = {10.1016/j.envres.2016.07.008}, pmid = {27448729}, issn = {1096-0953}, mesh = {Bacteria/drug effects/metabolism ; Bacterial Physiological Phenomena ; Biofilms/drug effects ; *Bioreactors ; Cerium/*toxicity ; Metal Nanoparticles/*toxicity ; Oxygen ; Phosphorus/*metabolism ; Water Pollutants, Chemical/*metabolism/*toxicity ; }, abstract = {The effects of CeO2 nanoparticles (CeO2 NPs) on a sequencing batch biofilm reactor (SBBR) with established biological phosphorus (P) removal were investigated from the processes of anaerobic P release and aerobic P uptake. At low concentration (0.1mg/L), no significant impact was observed on total phosphorus (TP) removal after operating for 8h. However, at a concentration of 20mg/L, TP removal efficiency decreased from 83.68% to 55.88% and 16.76% when the CeO2 NPs were added at the beginning of the anaerobic and aerobic periods, respectively. Further studies illustrated that the inhibition of the specific P release rate was caused by the reversible states of Ce[3+] and Ce[4+], which inhibited the activity of exopolyphosphatase (PPX) and transformation of poly-β-hydoxyalkanoates (PHA) and glycogen, as well as the uptake of volatile fatty acids (VFAs). The decrease in the specific P uptake rate was mainly attributed to the significantly suppressed energy generation and decreased abundance of Burkholderia caused by excess reactive oxygen species. The removal of chemical oxygen demand (COD) was not influenced by CeO2 NPs under aerobic conditions, due to the increased abundance of Acetobacter and Acidocella after exposure. The inhibitory effects of CeO2 NPs with molecular oxygen were reduced after anaerobic exposure due to the enhanced particle size and the presence of Ce[3+].}, } @article {pmid27755287, year = {2018}, author = {Farooq, AV and Hou, JH and Jassim, S and Haq, Z and Tu, EY and de la Cruz, J and Cortina, MS}, title = {Biofilm Formation on Bandage Contact Lenses Worn by Patients with the Boston Type 1 Keratoprosthesis: A Pilot Comparison Study of Prophylactic Topical Vancomycin 15 mg/mL and Linezolid 0.2.}, journal = {Eye & contact lens}, volume = {44 Suppl 1}, number = {}, pages = {S106-S109}, doi = {10.1097/ICL.0000000000000337}, pmid = {27755287}, issn = {1542-233X}, mesh = {Anti-Bacterial Agents/administration & dosage/*therapeutic use ; *Antibiotic Prophylaxis ; Bandages ; *Biofilms/drug effects/growth & development ; Contact Lenses, Hydrophilic/*microbiology ; Corneal Diseases/*prevention & control ; Humans ; Linezolid/administration & dosage/*therapeutic use ; Pilot Projects ; Prostheses and Implants/*adverse effects ; *Prosthesis-Related Infections/microbiology/prevention & control ; Vancomycin/administration & dosage/*therapeutic use ; }, abstract = {OBJECTIVES: To determine the rate of biofilm formation on bandage contact lenses worn by patients with the Boston type 1 keratoprosthesis (K-Pro) while on prophylactic topical vancomycin versus linezolid.

METHODS: Patients wearing a bandage contact lens (BCL) with a K-Pro were eligible for enrollment. After irrigation of the ocular surface with 5% povidone-iodine solution, each patient was placed on either topical vancomycin 15 mg/mL or linezolid 0.2% BID for one month. At the one-month visit, the BCL was collected and stored in fixative solution. Standard photographs were taken of each lens at high magnification using scanning electron microscopy (SEM), which were subsequently analyzed for evidence of biofilm.

RESULTS: Nineteen contact lenses were obtained from 12 K-Pro patients at the Illinois Eye and Ear Infirmary. Zero of eight (0%; 95% CI=0 to 37%) contact lenses from patients treated with topical vancomycin, and 1 of 11 (9%; 95% CI=0 to 41%; P-value=1.00) contact lenses from patients treated with topical linezolid were found to have biofilm formation at one month as detected by SEM. None of the patients developed a clinically significant infection while on either prophylactic vancomycin or linezolid during the study period.

CONCLUSIONS: Overall, the rate of biofilm formation as detected by SEM on the surface of bandage contact lenses was low. These results suggest that vancomycin and linezolid are both relatively effective in reducing biofilm-forming bacterial growth at one month. Accordingly, linezolid may be an effective alternative to vancomycin in patients with allergy or intolerance. However, further investigation is required to develop evidence-based antibiotic prophylaxis regimens.}, } @article {pmid27664057, year = {2016}, author = {Chung, PY}, title = {The emerging problems of Klebsiella pneumoniae infections: carbapenem resistance and biofilm formation.}, journal = {FEMS microbiology letters}, volume = {363}, number = {20}, pages = {}, doi = {10.1093/femsle/fnw219}, pmid = {27664057}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Carbapenems/*therapeutic use ; Humans ; Klebsiella Infections/*drug therapy ; Klebsiella pneumoniae/*drug effects/growth & development ; Opportunistic Infections/drug therapy/microbiology ; Urinary Catheters/microbiology ; beta-Lactam Resistance/*genetics ; beta-Lactamases/genetics/metabolism ; }, abstract = {Klebsiella pneumoniae is an opportunistic pathogen that commonly causes nosocomial infections in the urinary tract, respiratory tract, lung, wound sites and blood in individuals with debilitating diseases. Klebsiella pneumoniae is still a cause of severe pneumonia in alcoholics in Africa and Asia, and the predominant primary pathogen of primary liver abscess in Taiwan and Southeast Asia, particularly in Asian and Hispanic patients, and individuals with diabetes mellitus. In the United States and Europe, K. pneumoniae infections are most frequently associated with nosocomial infections. The emergence of antibiotic-resistant strains of K. pneumoniae worldwide has become a cause of concern where extended-spectrum β-lactamases (ESBLs) and carbapenemase-producing strains have been isolated with increasing frequency. The pathogen's ability to form biofilms on inserted devices such as urinary catheter has been proposed as one of the important mechanisms in nosocomially acquired and persistent infections, adding to the increased resistance to currently used antibiotics. In this review, infections caused by K. pneumoniae, antibiotic resistance and formation of biofilm will be discussed.}, } @article {pmid27616552, year = {2016}, author = {Jones, CC and Valdeig, S and Sova, RM and Weiss, CR}, title = {Inside-out Ultraviolet-C Sterilization of Pseudomonas aeruginosa Biofilm In Vitro.}, journal = {Photochemistry and photobiology}, volume = {92}, number = {6}, pages = {835-841}, pmid = {27616552}, issn = {1751-1097}, support = {UL1 TR001079/TR/NCATS NIH HHS/United States ; }, mesh = {Biofilms/*radiation effects ; In Vitro Techniques ; Lethal Dose 50 ; Pseudomonas aeruginosa/*radiation effects ; Sterilization/*methods ; *Ultraviolet Rays ; }, abstract = {Biofilms are difficult to eradicate due to a protective architecture and create major challenges in patient care by diminishing both host immune response and therapeutic approaches. This study investigated a new strategy for treating surface-attached biofilms by delivering germicidal UV through a material surface in a process referred to as "inside-out sterilization" (IOS). Mature Pseudomonas aeruginosa (ATCC[®] 27853[™]) biofilms were irradiated with up to 1400 mJ cm[-2] of germicidal UV from both ambient and IOS configurations. The lethal dose for the ambient exposure group was 461 mJ cm[-2] 95% CI [292, 728] compared to the IOS treatment group of 247 mJ cm[-2] 95% CI [187, 325], corresponding to 47% less UV dosage for the IOS group (P < 0.05). This study demonstrated that with IOS, a lower quantal dosage of UV energy is required to eradicate biofilm than with ambient exposure by leveraging the organizational structure of the biofilm.}, } @article {pmid27750384, year = {2017}, author = {Galarraga-Vinueza, ME and Mesquita-Guimarães, J and Magini, RS and Souza, JC and Fredel, MC and Boccaccini, AR}, title = {Anti-biofilm properties of bioactive glasses embedding organic active compounds.}, journal = {Journal of biomedical materials research. Part A}, volume = {105}, number = {2}, pages = {672-679}, doi = {10.1002/jbm.a.35934}, pmid = {27750384}, issn = {1552-4965}, mesh = {Animals ; *Anti-Infective Agents/chemistry/therapeutic use ; Biofilms/*drug effects/growth & development ; Bone Regeneration/*drug effects ; *Bone Substitutes/chemistry/therapeutic use ; *Ceramics/chemistry/therapeutic use ; *Coated Materials, Biocompatible/chemistry/therapeutic use ; Humans ; }, abstract = {Bioactive glasses (BGs) are promising materials for bone repair due to their desirable properties such as osteoconductivity, biodegradability, angiogenic potential, and antibacterial activity. Ionic dissolution products from bioactive glasses increase the medium pH inhibiting surrounding bacteria proliferation. The activity of BGs against biofilm formation has been enhanced by incorporating organic antibacterial compounds. The aim of this review was to summarize evidence in literature which assesses the efficacy of antibacterial and anti-biofilm compounds embedded in bioactive glasses to prevent peri-implant infection during bone healing. A PubMed bibliographical research was carried out including articles published in the last 20 years. Most previous studies evaluated antibacterial efficiency in planktonic cultures but did not investigate biofilm inhibition, underestimating biofilm clinical relevance. Multifactorial features such as biocompatibility of embedded compounds, receptor site characteristics, and drug delivery efficiency have been found to influence the bioactive glass capability of acting both as an anti-biofilm agent and as a bone repairing biomaterial. Accordingly, further in vitro and in vivo studies are required to select the most promising anti-biofilm agents which should be incorporated into bioactive glasses to counteract biofilm proliferation, without inducing toxic effects on human cells, and with the added functionality of promoting bone regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 672-679, 2017.}, } @article {pmid27748511, year = {2017}, author = {Blanken, W and Schaap, S and Theobald, S and Rinzema, A and Wijffels, RH and Janssen, M}, title = {Optimizing carbon dioxide utilization for microalgae biofilm cultivation.}, journal = {Biotechnology and bioengineering}, volume = {114}, number = {4}, pages = {769-776}, doi = {10.1002/bit.26199}, pmid = {27748511}, issn = {1097-0290}, mesh = {*Biofilms ; *Biomass ; Carbon Dioxide/*metabolism ; Microalgae/*metabolism ; *Models, Biological ; Photobioreactors ; Reproducibility of Results ; }, abstract = {The loss of carbon dioxide (CO2) to the environment during microalgae cultivation is undesirable for both environmental and economic reasons. In this study, a phototrophic biofilm growth model was developed and validated with the objective to maximize both CO2 utilization efficiency and production of microalgae in biofilms. The model was validated in growth experiments with CO2 as the limiting substrate. The CO2 utilization and biomass productivity were maximized by changing the gas flow rate, the number of biofilm reactors in series and gas composition. Based on simulations, the maximum CO2 utilization efficiency that was reached was 96% based on a process employing flue gas. The corresponding drop in productivity was only 2% in comparison to the non-CO2 limited reference situation. In order to achieve this, 25 biofilm reactors units, or more, must be operated in series. Based on these results, it was concluded that concentrated CO2 streams and plug flow behavior of the gaseous phase over the biofilm surface are essential for high productivity and CO2 utilization efficiency. Biotechnol. Bioeng. 2017;114: 769-776. © 2016 Wiley Periodicals, Inc.}, } @article {pmid27747298, year = {2016}, author = {Schaeffer, CR and Hoang, TN and Sudbeck, CM and Alawi, M and Tolo, IE and Robinson, DA and Horswill, AR and Rohde, H and Fey, PD}, title = {Versatility of Biofilm Matrix Molecules in Staphylococcus epidermidis Clinical Isolates and Importance of Polysaccharide Intercellular Adhesin Expression during High Shear Stress.}, journal = {mSphere}, volume = {1}, number = {5}, pages = {}, pmid = {27747298}, issn = {2379-5042}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; R01 GM080602/GM/NIGMS NIH HHS/United States ; }, abstract = {Staphylococcus epidermidis is a leading cause of hospital-associated infections, including those of intravascular catheters, cerebrospinal fluid shunts, and orthopedic implants. Multiple biofilm matrix molecules with heterogeneous characteristics have been identified, including proteinaceous, polysaccharide, and nucleic acid factors. Two of the best-studied components in S. epidermidis include accumulation-associated protein (Aap) and polysaccharide intercellular adhesin (PIA), produced by the enzymatic products of the icaADBC operon. Biofilm composition varies by strain as well as environmental conditions, and strains producing PIA-mediated biofilms are more robust. Clinically, biofilm-mediated infections occur in a variety of anatomical sites with diverse physiological properties. To test the hypothesis that matrix composition exhibits niche specificity, biofilm-related genetic and physical properties were compared between S. epidermidis strains isolated from high-shear and low-shear environments. Among a collection of 105 clinical strains, significantly more isolates from high-shear environments carried the icaADBC operon than did those from low-shear settings (43.9% versus 22.9%, P < 0.05), while there was no significant difference in the presence of aap (77.2% versus 75.0%, P > 0.05). Additionally, a significantly greater number of high-shear isolates were capable of forming biofilm in vitro in a microtiter assay (82.5% versus 45.8%, P < 0.0001). However, even among high-shear clinical isolates, less than half contained the icaADBC locus; therefore, we selected for ica-negative variants with increased attachment to abiotic surfaces to examine PIA-independent biofilm mechanisms. Sequencing of selected variants identified substitutions capable of enhancing biofilm formation in multiple genes, further highlighting the heterogeneity of S. epidermidis biofilm molecules and mechanisms. IMPORTANCEStaphylococcus epidermidis is a leading cause of infections related to biomaterials, mostly due to their ability to form biofilm. Biofilm accumulation mechanisms vary, including those that are dependent on specific proteins, environmental DNA (eDNA), or polysaccharide intercellular adhesin (PIA). We found that those isolates obtained from high-shear environments, such as the lumen of a catheter, are more likely to produce PIA-mediated biofilms than those isolates obtained from a low-shear biomaterial-related infection. This suggests that PIA functions as a mechanism that is protective against shear flow. Finally, we performed selection experiments documenting the heterogeneity of biofilm accumulation molecules that function in the absence of PIA, further documenting the biofilm-forming potential of S. epidermidis.}, } @article {pmid27747284, year = {2016}, author = {Yamabe, A and Irisawa, A and Wada, I and Shibukawa, G and Fujisawa, M and Sato, A and Igarashi, R and Maki, T and Hoshi, K}, title = {Application of a silver coating on plastic biliary stents to prevent biofilm formation: an experimental study using electron microscopy.}, journal = {Endoscopy international open}, volume = {4}, number = {10}, pages = {E1090-E1095}, pmid = {27747284}, issn = {2364-3722}, abstract = {Background and study aims: Biliary stent dysfunction is mainly caused by biliary sludge that forms as a result of bacterial adherence and subsequent biofilm formation on the inner surface of the stent. Silver ions arewell known to have excellent antimicrobial activity against a wide range of microorganisms. In this study, we designed and constructed silver-coated plastic stent (PS) and investigated whether the silver coating prevented bacterial adherence and biofilm formation through the use of electron microscopy. Material and methods: The polyurethane PS with/without silver coating were prepared in 6-inch segments. The silver-based antimicrobial agents were electrostatically applied onto the stent surface. The stents were then immersed for 5 weeks in infected human bile juice obtained from a patient with cholangitis, and electron microscopy was used to investigate the ability of the modified PS to prevent bacterial adherence and biofilm formation. Results: The bacterial flora did not change before and after immersion of stents in both the group with and without silver coating. Electron microscopic observation revealed meshwork-like structures around the bacteria, characteristic of biofilm-forming bacteria, in all stents from the control group (6/6, 100 %). On the other hand, a limited number of bacteria were observed in all stents in the silver-coated group, and no apparent biofilm formation was observed (0/6, 0 %). Conclusions: The significance of the findings from our study is the ability of silver-coated PS to prevent biofilm formation on the stent surface, which results in the prevention of stent occlusion.}, } @article {pmid27744709, year = {2016}, author = {García, S and Trueba, A and Vega, LM and Madariaga, E}, title = {Impact of the surface roughness of AISI 316L stainless steel on biofilm adhesion in a seawater-cooled tubular heat exchanger-condenser.}, journal = {Biofouling}, volume = {32}, number = {10}, pages = {1185-1193}, doi = {10.1080/08927014.2016.1241875}, pmid = {27744709}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Biofouling/*prevention & control ; Hot Temperature ; *Seawater ; Stainless Steel/*chemistry ; Surface Properties ; Thermal Conductivity ; Water Movements ; }, abstract = {The present study evaluated biofilm growth in AISI 316L stainless steel tubes for seawater-cooled exchanger-condensers that had four different arithmetic mean surface roughness values ranging from 0.14 μm to 1.2 μm. The results of fluid frictional resistance and heat transfer resistance regarding biofilm formation in the roughest surface showed increases of 28.2% and 19.1% respectively, compared with the smoothest surface. The biofilm thickness taken at the end of the experiment showed variations of up to 74% between the smoothest and roughest surfaces. The thermal efficiency of the heat transfer process in the tube with the roughest surface was 17.4% greater than that in the tube with the smoothest surface. The results suggest that the finish of the inner surfaces of the tubes in heat exchanger-condensers is critical for improving energy efficiency and avoiding biofilm adhesion. This may be utilised to reduce biofilm adhesion and growth in the design of heat exchanger-condensers.}, } @article {pmid27604596, year = {2017}, author = {Losensky, G and Jung, K and Urlaub, H and Pfeifer, F and Fröls, S and Lenz, C}, title = {Shedding light on biofilm formation of Halobacterium salinarum R1 by SWATH-LC/MS/MS analysis of planktonic and sessile cells.}, journal = {Proteomics}, volume = {17}, number = {7}, pages = {}, doi = {10.1002/pmic.201600111}, pmid = {27604596}, issn = {1615-9861}, mesh = {Archaeal Proteins/*analysis/genetics/metabolism ; Biofilms/*growth & development ; Chromatography, Liquid ; *Gene Expression Regulation, Archaeal ; Halobacterium salinarum/*chemistry/genetics/metabolism ; Plankton/chemistry/growth & development/metabolism ; Proteome/*analysis ; Tandem Mass Spectrometry ; }, abstract = {Early and mature biofilm formation in the extremely halophilic euryarchaeon Halobacterium salinarum strain R1 was characterized by SWATH-LC/MS/MS. Using a simple surfactant-assisted protein solubilization protocol and one-dimensional ultra-high performance nanoflow chromatography on the front end, 63.2 and 58.6% of the predicted H. salinarum R1 proteome could be detected and quantified, respectively. Analysis of biophysical protein properties, functional analysis and pathway mapping indicated comprehensive characterization of the proteome. Sixty point eight percent of the quantified proteins (or 34.5% of the predicted proteome) exhibited significant abundance changes between planktonic and sessile states, demonstrating that haloarchaeal biofilm formation represents a profound "lifestyle change" on the molecular level. Our results and analysis constitute the first comprehensive study to track molecular changes from planktonic cultures to initial and mature archaeal biofilms on the proteome level. Data are available via ProteomeXchange, identifier PXD003667. Proteins exemplifying different protein expression level profiles were selected, and their corresponding gene transcripts targeted by qRT-PCR to test the feasibility of establishing rapid PCR-based assays for archaeal biofilm formation.}, } @article {pmid27744638, year = {2017}, author = {Jin, L and Ko, SR and Cui, Y and Lee, CS and Oh, HM and Ahn, CY and Lee, HG}, title = {Pusillimonas caeni sp. nov., isolated from a sludge sample of a biofilm reactor.}, journal = {Antonie van Leeuwenhoek}, volume = {110}, number = {1}, pages = {125-132}, doi = {10.1007/s10482-016-0782-6}, pmid = {27744638}, issn = {1572-9699}, mesh = {Alcaligenaceae/classification/genetics/*isolation & purification/metabolism ; Bacterial Typing Techniques ; Base Composition ; *Biofilms ; DNA, Bacterial/genetics ; Fatty Acids/chemistry/metabolism ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Republic of Korea ; Sewage/*microbiology ; }, abstract = {A polyphasic taxonomic study was carried out on strain EBR-8-1[T] isolated from a biofilm reactor in Korea. The cells of the strain were Gram-stain negative, non-spore-forming, non-motile, and short rod-shaped. Comparative 16S rRNA gene sequence studies showed a clear affiliation of this strain with Betaproteobacteria, which showed high pairwise sequence similarities with Pusillimonas noertemannii BN9[T] (99.1 %), Pusillimonas soli MJ07[T] (97.3 %), Pusillimonas ginsengisoli DCY25[T] (97.2 %), and Pusillimonas harenae B201[T] (96.8 %). The phylogenetic analysis based on 16S rRNA gene sequences showed that the strain formed a clear phylogenetic lineage within the genus Pusillimonas. The major fatty acids were identified as C16:0, C17:0 cyclo and C19:0 cyclo ω8c. The major cellular polar lipids were identified as phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid. The respiratory quinone was identified as Q-8 and the genomic DNA G+C content was determined to be 63.3 mol%. On the basis of polyphasic evidence, it is proposed that strain EBR-8-1[T] should be placed in a new species, Pusillimonas caeni sp. nov. The type stain is EBR-8-1[T] (=KCTC 42353[T] = JCM 30463[T]).}, } @article {pmid27744062, year = {2017}, author = {Pourhajibagher, M and Chiniforush, N and Ghorbanzadeh, R and Bahador, A}, title = {Photo-activated disinfection based on indocyanine green against cell viability and biofilm formation of Porphyromonas gingivalis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {17}, number = {}, pages = {61-64}, doi = {10.1016/j.pdpdt.2016.10.003}, pmid = {27744062}, issn = {1873-1597}, mesh = {Biofilms/*drug effects ; Cell Survival/drug effects ; Disinfection/*methods ; Dose-Response Relationship, Drug ; Indocyanine Green/administration & dosage/*pharmacology ; Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/administration & dosage/*pharmacology ; Porphyromonas gingivalis/*drug effects ; }, abstract = {BACKGROUND: Photo-activated disinfection (PAD) is a novel treatment approach, in which bacteria in the root canal system may be exposed to sub-lethal doses of PAD. Such exposure can affect bacterial survival and virulence features, such as biofilm formation ability. The aim of this study was to evaluate the effects of sub-lethal doses of PAD (sPAD) using indocyanine green (ICG) on load and biofilm formation ability of Porphyromonas gingivalis as an anaerobic bacterium associated with endodontic infection.

MATERIALS AND METHODS: The anti-bacterial and anti-biofilm potential of sPAD against P. gingivalis at sub-lethal doses of ICG as a photosensitizer and using 810nm wavelength of diode laser light via colony forming unit and crystal violet assays, respectively, was determined.

RESULTS: High concentrations of ICG and light irradiation time significantly reduced bacteria. High doses of sPAD markedly reduced the number of bacteria and the formation of biofilm, up to 30.4% and 25.1%, respectively.

CONCLUSION: High doses of sPAD affected cell viability and the biofilm formation ability of P. gingivalis; lower doses did not. Thus, selection of appropriate PAD dosage should be considered for the successful treatment of endodontic in vivo.}, } @article {pmid27742449, year = {2016}, author = {Celikkol-Aydin, S and Gaylarde, CC and Lee, T and Melchers, RE and Witt, DL and Beech, IB}, title = {16S rRNA gene profiling of planktonic and biofilm microbial populations in the Gulf of Guinea using Illumina NGS.}, journal = {Marine environmental research}, volume = {122}, number = {}, pages = {105-112}, doi = {10.1016/j.marenvres.2016.10.001}, pmid = {27742449}, issn = {1879-0291}, mesh = {Bacteria/classification/*genetics ; Biodiversity ; Biofilms/*classification ; Environmental Monitoring/*methods ; Guinea ; Plankton/classification/*genetics ; RNA, Ribosomal, 16S ; Seawater/*microbiology ; }, abstract = {16S rRNA gene profiling using a pipeline involving the Greengenes database revealed that bacterial populations in innermost (proximal to the steel surface) and outer regions of biofilms on carbon steel exposed 3 m below the surface at an offshore site in the Gulf of Guinea differed from one another and from seawater. There was a preponderance of gammaproteobacterial sequences, representing organisms known for hydrocarbon degradation. Total DNA from the innermost layer was 1500 times that recovered from the outermost. Stramenopiles (diatom) sequences were prevalent in the former. Rhodobacteriaceae, key biofilm formers, comprised 14.9% and 4.22% OTUs of inner and outer layers, respectively. Photosynthetic anaerobic sulfur oxidizer sequences were also prominent in the biofilms. Analysis of data using a different pipeline with Silva111 allowed detection of 0.3-0.4% SRB in the biofilms. The high abundance of aerobic micro-algal sequences in inner biofilm suggests they are initial colonizers of carbon steel surfaces in a marine environment. This is the first time that the microbial population of the strongly attached inner layer of the biofilm on steel has been differentiated from the outer, readily removed layer. The accepted scraping removal method is obviously inadequate and the resulting microbial analysis does not offer complete information on the biofilm community structure.}, } @article {pmid27739486, year = {2016}, author = {Lee, TH and Jang, BS and Jung, MK and Pack, CG and Choi, JH and Park, DH}, title = {Fabrication of a silver particle-integrated silicone polymer-covered metal stent against sludge and biofilm formation and stent-induced tissue inflammation.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {35446}, pmid = {27739486}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; *Biofilms ; Cell Line ; Escherichia coli/drug effects/physiology ; Female ; Klebsiella pneumoniae/drug effects/physiology ; Metal Nanoparticles/chemistry/*therapeutic use ; Mice ; Prosthesis-Related Infections/*prevention & control ; Self Expandable Metallic Stents/adverse effects/*microbiology/standards ; Silicones/chemistry ; Silver/chemistry/pharmacology ; Swine ; Swine, Miniature ; }, abstract = {To reduce tissue or tumor ingrowth, covered self-expandable metal stents (SEMSs) have been developed. The effectiveness of covered SEMSs may be attenuated by sludge or stone formation or by stent clogging due to the formation of biofilm on the covering membrane. In this study, we tested the hypothesis that a silicone membrane containing silver particles (Ag-P) would prevent sludge and biofilm formation on the covered SEMS. In vitro, the Ag-P-integrated silicone polymer-covered membrane exhibited sustained antibacterial activity, and there was no definite release of silver ions from the Ag-P-integrated silicone polymer membrane at any time point. Using a porcine stent model, in vivo analysis demonstrated that the Ag-P-integrated silicone polymer-covered SEMS reduced the thickness of the biofilm and the quantity of sludge formed, compared with a conventional silicone-covered SEMS. In vivo, the release of silver ions from an Ag-P-integrated silicone polymer-covered SEMS was not detected in porcine serum. The Ag-P-integrated silicone polymer-covered SEMS also resulted in significantly less stent-related bile duct and subepithelium tissue inflammation than a conventional silicone polymer-covered SEMS. Therefore, the Ag-P-integrated silicone polymer-covered SEMS reduced sludge and biofilm formation and stent-induced pathological changes in tissue. This novel SEMS may prolong the stent patency in clinical application.}, } @article {pmid27739324, year = {2016}, author = {Rama Devi, K and Srinivasan, R and Kannappan, A and Santhakumari, S and Bhuvaneswari, M and Rajasekar, P and Prabhu, NM and Veera Ravi, A}, title = {In vitro and in vivo efficacy of rosmarinic acid on quorum sensing mediated biofilm formation and virulence factor production in Aeromonas hydrophila.}, journal = {Biofouling}, volume = {32}, number = {10}, pages = {1171-1183}, doi = {10.1080/08927014.2016.1237220}, pmid = {27739324}, issn = {1029-2454}, mesh = {Aeromonas hydrophila/genetics/metabolism/pathogenicity/*physiology ; Biofilms/*drug effects/growth & development ; Cinnamates/*pharmacology ; Depsides/*pharmacology ; Down-Regulation ; Microbial Sensitivity Tests ; Quorum Sensing/*drug effects ; Spectroscopy, Fourier Transform Infrared ; Virulence ; Virulence Factors/genetics/*metabolism ; }, abstract = {Rosmarinic acid (RA) was assessed for its quorum sensing inhibitory (QSI) potential against Aeromonas hydrophila strains AH 1, AH 12 and MTCC 1739. The pathogenic strains of A. hydrophila were isolated from infected zebrafish and identified through biochemical analysis and amplification of a species-specific gene (rpsL). The biofilm inhibitory concentration (BIC) of RA against A. hydrophila strains was found to be 750 μg ml[-1]. At this concentration, RA reduced the QS mediated hemolysin, lipase and elastase production in A. hydrophila. In FT-IR analysis, RA treated A. hydrophila cells showed a reduction in cellular components. Gene expression analysis confirmed the down-regulation of virulence genes such as ahh1, aerA, lip and ahyB. A. hydrophila infected zebrafish upon treatment with RA showed increased survival rates. Thus, the present study demonstrates the use of RA as a plausible phytotherapeutic compound to control QS mediated biofilm formation and virulence factor production in A. hydrophila.}, } @article {pmid27737569, year = {2017}, author = {}, title = {Correction to: bactericidal, quorum quenching and anti-biofilm nanofactories: a new niche for nanotechnologists.}, journal = {Critical reviews in biotechnology}, volume = {37}, number = {2}, pages = {275}, doi = {10.1080/07388551.2016.1232474}, pmid = {27737569}, issn = {1549-7801}, } @article {pmid27736961, year = {2016}, author = {Banar, M and Emaneini, M and Satarzadeh, M and Abdellahi, N and Beigverdi, R and Leeuwen, WB and Jabalameli, F}, title = {Evaluation of Mannosidase and Trypsin Enzymes Effects on Biofilm Production of Pseudomonas aeruginosa Isolated from Burn Wound Infections.}, journal = {PloS one}, volume = {11}, number = {10}, pages = {e0164622}, pmid = {27736961}, issn = {1932-6203}, mesh = {Biofilms/drug effects ; Burns/*complications ; Ceftazidime/pharmacology ; Cell Line ; Humans ; Mannosidases/adverse effects/*pharmacology ; Microbial Sensitivity Tests ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification ; Trypsin/*pharmacology/therapeutic use ; Wound Infection/drug therapy/*microbiology ; alpha-Mannosidase/adverse effects/pharmacology ; beta-Mannosidase/adverse effects/pharmacology ; }, abstract = {Biofilm is an important virulence factor in Pseudomonas aeruginosa and has a substantial role in antibiotic resistance and chronic burn wound infections. New therapeutic agents against P. aeruginosa, degrading biofilms in burn wounds and improving the efficacy of current antimicrobial agents, are required. In this study, the effects of α-mannosidase, β-mannosidase and trypsin enzymes on the degradation of P. aeruginosa biofilms and on the reduction of ceftazidime minimum biofilm eliminating concentrations (MBEC) were evaluated. All tested enzymes, destroyed the biofilms and reduced the ceftazidime MBECs. However, only trypsin had no cytotoxic effect on A-431 human epidermoid carcinoma cell lines. In conclusion, since trypsin had better features than mannosidase enzymes, it can be a promising agent in combatting P. aeruginosa burn wound infections.}, } @article {pmid27735846, year = {2016}, author = {Kłodzińska, SN and Priemel, PA and Rades, T and Mørck Nielsen, H}, title = {Inhalable Antimicrobials for Treatment of Bacterial Biofilm-Associated Sinusitis in Cystic Fibrosis Patients: Challenges and Drug Delivery Approaches.}, journal = {International journal of molecular sciences}, volume = {17}, number = {10}, pages = {}, pmid = {27735846}, issn = {1422-0067}, mesh = {Administration, Inhalation ; Anti-Infective Agents/chemistry/pharmacology/*therapeutic use ; Biofilms/drug effects/*growth & development ; Cystic Fibrosis/*complications/pathology ; Drug Carriers/*chemistry ; Drug Compounding ; Humans ; Pseudomonas aeruginosa/physiology ; Sinusitis/complications/*drug therapy/microbiology ; }, abstract = {Bacterial biofilm-associated chronic sinusitis in cystic fibrosis (CF) patients caused by Pseudomonas aeruginosa infections and the lack of available treatments for such infections constitute a critical aspect of CF disease management. Currently, inhalation therapies to combat P. aeruginosa infections in CF patients are focused mainly on the delivery of antimicrobials to the lower respiratory tract, disregarding the sinuses. However, the sinuses constitute a reservoir for P. aeruginosa growth, leading to re-infection of the lungs, even after clearing an initial lung infection. Eradication of P. aeruginosa from the respiratory tract after a first infection has been shown to delay chronic pulmonary infection with the bacteria for up to two years. The challenges with providing a suitable treatment for bacterial sinusitis include: (i) identifying a suitable antimicrobial compound; (ii) selecting a suitable device to deliver the drug to the sinuses and nasal cavities; and (iii) applying a formulation design, which will mediate delivery of a high dose of the antimicrobial directly to the site of infection. This review highlights currently available inhalable antimicrobial formulations for treatment and management of biofilm infections caused by P. aeruginosa and discusses critical issues related to novel antimicrobial drug formulation design approaches.}, } @article {pmid27734161, year = {2017}, author = {Kaiser, SJ and Mutters, NT and DeRosa, A and Ewers, C and Frank, U and Günther, F}, title = {Determinants for persistence of Pseudomonas aeruginosa in hospitals: interplay between resistance, virulence and biofilm formation.}, journal = {European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology}, volume = {36}, number = {2}, pages = {243-253}, pmid = {27734161}, issn = {1435-4373}, mesh = {Bacterial Proteins/genetics ; Biofilms/*growth & development ; Cluster Analysis ; Cross Infection/microbiology ; Drug Resistance, Multiple, Bacterial ; Environmental Microbiology ; Genotype ; *Hospitals ; Humans ; Molecular Typing ; Polymerase Chain Reaction ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/classification/drug effects/*isolation & purification/*physiology ; Random Amplified Polymorphic DNA Technique ; Virulence ; Virulence Factors/genetics ; beta-Lactamases/genetics ; }, abstract = {Pseudomonas aeruginosa (Pa) is one of the major bacterial pathogens causing nosocomial infections. During the past few decades, multidrug-resistant (MDR) and extensively drug-resistant (XDR) lineages of Pa have emerged in hospital settings with increasing numbers. However, it remains unclear which determinants of Pa facilitated this spread. A total of 211 clinical XDR and 38 susceptible clinical Pa isolates (nonXDR), as well as 47 environmental isolates (EI), were collected at the Heidelberg University Hospital. We used RAPD PCR to identify genetic clusters. Carriage of carbapenamases (CPM) and virulence genes were analyzed by PCR, biofilm formation capacity was assessed, in vitro fitness was evaluated using competitive growth assays, and interaction with the host's immune system was analyzed using serum killing and neutrophil killing assays. XDR isolates showed significantly elevated biofilm formation (p < 0.05) and higher competitive fitness compared to nonXDR and EI isolates. Thirty percent (62/205) of the XDR isolates carried a CPM. Similarities in distribution of virulence factors, as well as biofilm formation properties, between CPM+ Pa isolates and EI and between CPM- and nonXDR isolates were detected. Molecular typing revealed two distinct genetic clusters within the XDR population, which were characterized by even higher biofilm formation. In contrast, XDR isolates were more susceptible to the immune response than nonXDR isolates. Our study provides evidence that the ability to form biofilms is an outstanding determinant for persistence and endemic spread of Pa in the hospital setting.}, } @article {pmid27734125, year = {2017}, author = {Ding, ZW and Lu, YZ and Fu, L and Ding, J and Zeng, RJ}, title = {Simultaneous enrichment of denitrifying anaerobic methane-oxidizing microorganisms and anammox bacteria in a hollow-fiber membrane biofilm reactor.}, journal = {Applied microbiology and biotechnology}, volume = {101}, number = {1}, pages = {437-446}, doi = {10.1007/s00253-016-7908-7}, pmid = {27734125}, issn = {1432-0614}, mesh = {Anaerobiosis ; Archaea/classification/genetics/isolation & purification/*metabolism ; Bacteria/classification/genetics/isolation & purification/*metabolism ; *Biofilms ; *Biota ; Cluster Analysis ; DNA, Archaeal/chemistry/genetics ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; *Denitrification ; High-Throughput Nucleotide Sequencing ; *Membranes ; Methane/*metabolism ; Nitrates/metabolism ; Oxidation-Reduction ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Water Purification ; }, abstract = {In this study, the coculture system of denitrifying anaerobic methane oxidation (DAMO) microbes and anaerobic ammonium oxidation (anammox) bacteria was successfully enriched in a hollow-fiber membrane biofilm reactor (HfMBR) using freshwater sediment as the inoculum. The maximal removal rates of nitrate and ammonium were 78 mg N/L/day (131 mg N/m[2]/day) and 26 mg N/L/day (43 mg N/m[2]/day), respectively. Due to the high rate of methane mass transfer in HfMBR, the activity of DAMO archaea continued to increase during the enrichment period, indicating that HfMBR could be a powerful tool to enrich DAMO microorganisms. Effects of partial methane pressure, temperature, and pH on the cocultures were obvious. However, the microbial activity in HfMBR could be recovered quickly after the shock change of environmental factors. Furthermore, the result also found that DAMO bacteria likely had a stronger competitive advantage than anammox bacteria under the operating conditions in this study. High-throughput sequencing 16S rRNA genes illustrated that the dominant microbes were NC10, Euryarchaeota, Proteobacteria, Planctomycetes, and Chlorobi with relative abundance of 38.8, 26.2, 13.78, 6.2, and 3.6 %, respectively.}, } @article {pmid27733226, year = {2016}, author = {Chen, W and Li, B and Li, S and Ou, YW and Ou, Q}, title = {Effects of Scutellaria Baicalensis on Activity and Biofilm Formation of Klebsiella Pneumoniae.}, journal = {Chinese medical sciences journal = Chung-kuo i hsueh k'o hsueh tsa chih}, volume = {31}, number = {3}, pages = {180-184}, doi = {10.1016/s1001-9294(16)30048-7}, pmid = {27733226}, issn = {1001-9294}, mesh = {Biofilms/*drug effects ; Integrons/drug effects ; Klebsiella pneumoniae/*drug effects/physiology ; Microbial Sensitivity Tests ; *Scutellaria baicalensis ; }, abstract = {Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia (Kp).Methods The broth and agar dilution Methods were carried out to determine minimum inhibitory concentration and minimum bactericidal concentration of Scutellaria baicalensis for TW518. VITEK-32 system was used to assay TW518 susceptibility to antibiotics. Kp biofilms were formed in vitro and stained with BacLight Live/Dead stain. The class integron geneⅠ1 mRNA expression was analyzed with RT-PCR.Results The minimum inhibitory concentration of Scutellaria baicalensis on TW518 identified as a Kp colony was 32 mg/ml, and minimum bactericidal concentration was 64 mg/ml. Scutellaria baicalensis and broad-spectrum penicillin, cephalosporin, quinolones, or beta-lactamase had synergistic bactericidal effects. Biofilm formation activity of Kp treated with Scutellaria baicalensis was significantly lower than that of the control group. And class integron geneⅠ1 mRNA expression of TW518 was significantly inhibited by Scutellaria baicalensis.Conclusions Scutellaria baicalensis has sterilization effect on Kp, and Scutellaria baicalensis could effectively inhibit Kp biofilm formation with prolonged treatment. Scutellaria baicalensis might inhibit Kp biofilm formation through down-regulating integron geneⅠ1 expression.}, } @article {pmid27732675, year = {2016}, author = {Réblová, M and Hubka, V and Thureborn, O and Lundberg, J and Sallstedt, T and Wedin, M and Ivarsson, M}, title = {From the Tunnels into the Treetops: New Lineages of Black Yeasts from Biofilm in the Stockholm Metro System and Their Relatives among Ant-Associated Fungi in the Chaetothyriales.}, journal = {PloS one}, volume = {11}, number = {10}, pages = {e0163396}, pmid = {27732675}, issn = {1932-6203}, mesh = {Animals ; Ants/*microbiology ; Ascomycota/classification/*genetics/physiology ; Base Sequence ; Bayes Theorem ; Biofilms ; DNA, Fungal/chemistry/isolation & purification/metabolism ; DNA, Ribosomal/chemistry/isolation & purification/metabolism ; Fungal Proteins/genetics ; Nucleic Acid Conformation ; Phylogeny ; RNA Polymerase II/genetics ; Sequence Alignment ; Sweden ; Tubulin/genetics ; }, abstract = {Rock-inhabiting fungi harbour species-rich, poorly differentiated, extremophilic taxa of polyphyletic origin. Their closest relatives are often well-known species from various biotopes with significant pathogenic potential. Speleothems represent a unique rock-dwelling habitat, whose mycobiota are largely unexplored. Isolation of fungi from speleothem biofilm covering bare granite walls in the Kungsträdgården metro station in Stockholm yielded axenic cultures of two distinct black yeast morphotypes. Phylogenetic analyses of DNA sequences from six nuclear loci, ITS, nuc18S and nuc28S rDNA, rpb1, rpb2 and β-tubulin, support their placement in the Chaetothyriales (Ascomycota). They are described as a new genus Bacillicladium with the type species B. lobatum, and a new species Bradymyces graniticola. Bacillicladium is distantly related to the known five chaetothyrialean families and is unique in the Chaetothyriales by variable morphology showing hyphal, meristematic and yeast-like growth in vitro. The nearest relatives of Bacillicladium are recruited among fungi isolated from cardboard-like construction material produced by arboricolous non-attine ants. Their sister relationship is weakly supported by the Maximum likelihood analysis, but strongly supported by Bayesian inference. The genus Bradymyces is placed amidst members of the Trichomeriaceae and is ecologically undefined; it includes an opportunistic animal pathogen while two other species inhabit rock surfaces. ITS rDNA sequences of three species accepted in Bradymyces and other undescribed species and environmental samples were subjected to phylogenetic analysis and in-depth comparative analysis of ITS1 and ITS2 secondary structures in order to study their intraspecific variability. Compensatory base change criterion in the ITS2 secondary structure supported delimitation of species in Bradymyces, which manifest a limited number of phenotypic features useful for species recognition. The role of fungi in the speleothem biofilm and relationships of Bacillicladium and Bradymyces with other members of the Chaetothyriales are discussed.}, } @article {pmid27731921, year = {2016}, author = {Thomann, A and Brengel, C and Börger, C and Kail, D and Steinbach, A and Empting, M and Hartmann, RW}, title = {Structure-Activity Relationships of 2-Sufonylpyrimidines as Quorum-Sensing Inhibitors to Tackle Biofilm Formation and eDNA Release of Pseudomonas aeruginosa.}, journal = {ChemMedChem}, volume = {11}, number = {22}, pages = {2522-2533}, doi = {10.1002/cmdc.201600419}, pmid = {27731921}, issn = {1860-7187}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; DNA, Bacterial/*drug effects/metabolism ; Dose-Response Relationship, Drug ; Molecular Structure ; Pseudomonas aeruginosa/cytology/*drug effects/metabolism ; Pyrimidines/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Drug-resistant Pseudomonas aeruginosa (PA) strains are on the rise, making treatment with current antibiotics ineffective. Hence, circumventing resistance or restoring the activity of antibiotics by novel approaches is of high demand. Targeting the Pseudomonas quinolone signal quorum sensing (PQS-QS) system is an intriguing strategy to abolish PA pathogenicity without affecting the viability of the pathogen. Herein we report the structure-activity relationships of 2-sulfonylpyrimidines, which were previously identified as dual-target inhibitors of the PQS receptor PqsR and the PQS synthase PqsD. The SAR elucidation was guided by a combined approach using ligand efficiency and ligand lipophilicity efficiency to select the most promising compounds. In addition, the most effective inhibitors were rationally modified by the guidance of QSAR using Hansch analyses. Finally, these inhibitors showed the capacity to decrease biofilm mass and extracellular DNA, which are important determinants for antibiotic resistance.}, } @article {pmid27729907, year = {2016}, author = {França, A and Pérez-Cabezas, B and Correia, A and Pier, GB and Cerca, N and Vilanova, M}, title = {Staphylococcus epidermidis Biofilm-Released Cells Induce a Prompt and More Marked In vivo Inflammatory-Type Response than Planktonic or Biofilm Cells.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1530}, pmid = {27729907}, issn = {1664-302X}, abstract = {Staphylococcus epidermidis biofilm formation on indwelling medical devices is frequently associated with the development of chronic infections. Nevertheless, it has been suggested that cells released from these biofilms may induce severe acute infections with bacteraemia as one of its major associated clinical manifestations. However, how biofilm-released cells interact with the host remains unclear. Here, using a murine model of hematogenously disseminated infection, we characterized the interaction of cells released from S. epidermidis biofilms with the immune system. Gene expression analysis of mouse splenocytes suggested that biofilm-released cells might be particularly effective at activating inflammatory and antigen presenting cells and inducing cellular apoptosis. Furthermore, biofilm-released cells induced a higher production of pro-inflammatory cytokines, in contrast to mice infected with planktonic cells, even though these had a similar bacterial load in livers and spleens. Overall, these results not only provide insights into the understanding of the role of biofilm-released cells in S. epidermidis biofilm-related infections and pathogenesis, but may also help explain the relapsing character of these infections.}, } @article {pmid27729510, year = {2016}, author = {Kong, EF and Tsui, C and Kucharíková, S and Andes, D and Van Dijck, P and Jabra-Rizk, MA}, title = {Commensal Protection of Staphylococcus aureus against Antimicrobials by Candida albicans Biofilm Matrix.}, journal = {mBio}, volume = {7}, number = {5}, pages = {}, pmid = {27729510}, issn = {2150-7511}, support = {K22 DE014424/DE/NIDCR NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; R01 AI130170/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Biofilms/*growth & development ; Candida albicans/*physiology ; *Drug Tolerance ; *Microbial Interactions ; Microbial Viability/*drug effects ; Microscopy, Confocal ; Staphylococcus aureus/*drug effects/physiology ; Time-Lapse Imaging ; }, abstract = {UNLABELLED: Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections.

IMPORTANCE: The fungus Candida albicans and the bacterium Staphylococcus aureus are important microbial pathogens responsible for the majority of infections in hospitalized patients and are often coisolated from a host. In this study, we demonstrated that when grown together, the fungus provides the bacterium with enhanced tolerance to antimicrobial drugs. This process was mediated by polysaccharides secreted by the fungal cell into the environment. The biofilm matrix formed by these polysaccharides prevented penetration by the drugs and provided the bacteria with protection. Importantly, we show that by inhibiting the production of the fungal polysaccharides, a specific antifungal agent indirectly sensitized the bacteria to antimicrobials. Understanding the therapeutic implications of the interactions between these two diverse microbial species will aid in overcoming the limitations of current therapies and in defining new targets for treating complex polymicrobial infections.}, } @article {pmid27728889, year = {2017}, author = {Suto, R and Ishimoto, C and Chikyu, M and Aihara, Y and Matsumoto, T and Uenishi, H and Yasuda, T and Fukumoto, Y and Waki, M}, title = {Anammox biofilm in activated sludge swine wastewater treatment plants.}, journal = {Chemosphere}, volume = {167}, number = {}, pages = {300-307}, doi = {10.1016/j.chemosphere.2016.09.121}, pmid = {27728889}, issn = {1879-1298}, mesh = {Ammonia/*analysis/chemistry/metabolism ; Anaerobiosis ; Animals ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Oxidation-Reduction ; Planctomycetales/genetics/growth & development ; RNA, Ribosomal, 16S/genetics ; Sewage/*chemistry/microbiology ; Swine ; Wastewater/*chemistry/microbiology ; Water Purification/*methods ; }, abstract = {We investigated anammox with a focus on biofilm in 10 wastewater treatment plants (WWTPs) that use activated sludge treatment of swine wastewater. In three plants, we found red biofilms in aeration tanks or final sedimentation tanks. The biofilm had higher anammox 16S rRNA gene copy numbers (up to 1.35 × 10[12] copies/g-VSS) and higher anammox activity (up to 295 μmoL/g-ignition loss/h) than suspended solids in the same tank. Pyrosequencing analysis revealed that Planctomycetes accounted for up to 17.7% of total reads in the biofilm. Most of them were related to Candidatus Brocadia or Ca. Jettenia. The highest copy number and the highest proportion of Planctomycetes were comparable to those of enriched anammox sludge. Thus, swine WWTPs that use activated sludge treatment can fortuitously acquire anammox biofilm. Thus, concentrated anammox can be detected by focusing on red biofilm.}, } @article {pmid27726082, year = {2017}, author = {Xu, J and Li, M and He, Q and Sun, X and Zhou, X and Su, Z and Ai, H}, title = {Effect of flow rate on growth and oxygen consumption of biofilm in gravity sewer.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {1}, pages = {427-435}, pmid = {27726082}, issn = {1614-7499}, mesh = {Biofilms/*growth & development ; Biological Oxygen Demand Analysis ; *Drainage, Sanitary ; Gravitation ; Microelectrodes ; Oxygen/*metabolism ; Porosity ; }, abstract = {The function of sewer as reactors must rely on the biofilm in it. In this paper, the formation, structure, oxygen transfer, and activity of the biofilm under different hydraulic conditions were studied by the microelectrode technology, oxygen uptake rate (OUR) technology, and 454 high-throughput pyrosequencing technology. Results showed that when the wall-shear stresses were 1.12, 1.29, and 1.45 Pa, the porosity of the steady-state biofilm were 69.1, 64.4, and 55.1 %, respectively. The maximum values of OUR were 0.033, 0.027, and 0.022 mg/(L*s), respectively, and the COD removal efficiency in the sewers reached 40, 35, and 32 %, respectively. The research findings had an important significance on how to improve the treatment efficiency of the sewers. Fig. a Graphical Abstract.}, } @article {pmid27721053, year = {2016}, author = {Srinivasan, R and Devi, KR and Kannappan, A and Pandian, SK and Ravi, AV}, title = {Piper betle and its bioactive metabolite phytol mitigates quorum sensing mediated virulence factors and biofilm of nosocomial pathogen Serratia marcescens in vitro.}, journal = {Journal of ethnopharmacology}, volume = {193}, number = {}, pages = {592-603}, doi = {10.1016/j.jep.2016.10.017}, pmid = {27721053}, issn = {1872-7573}, mesh = {Biofilms/*drug effects/growth & development ; Biomass ; Cross Infection/microbiology/urine ; Dose-Response Relationship, Drug ; Humans ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Phytol/isolation & purification/*pharmacology ; Piper betle/*chemistry/metabolism ; Plant Leaves/chemistry/metabolism ; Prodigiosin/antagonists & inhibitors ; Quorum Sensing/*drug effects ; Serratia marcescens/*drug effects/growth & development/metabolism/pathogenicity ; Virulence ; }, abstract = {Piper betle, a tropical creeper plant belongs to the family Piperaceae. The leaves of this plant have been well known for their therapeutic, religious and ceremonial value in South and Southeast Asia. It has also been reported to possess several biological activities including antimicrobial, antioxidant, antinociceptive, antidiabetic, insecticidal and gastroprotective activities and used as a common ingredient in indigenous medicines. In Indian system of ayurvedic medicine, P. betle has been well recognized for its antiseptic properties and is commonly applied on wounds and lesions for its healing effects.

AIM OF THE STUDY: To evaluate the anti-quorum sensing (anti-QS) and antibiofilm efficacy of P. betle and its bioactive metabolite phytol against Serratia marcescens.

MATERIALS AND METHODS: The P. betle ethyl acetate extract (PBE) was evaluated for its anti-QS efficacy against S. marcescens by assessing the prodigiosin and lipase production at 400 and 500µgml[-1] concentrations. In addition, the biofilm biomass quantification assay was performed to evaluate the antibiofilm activity of PBE against S. marcescens. Besides, the influence of PBE on bacterial biofilm formation was assessed through microscopic techniques. The biofilm related phenomenons like exopolysaccharides (EPS) production, hydrophobicity and swarming motility were also examined to support the antibiofilm activity of PBE. Transcriptional analysis of QS regulated genes in S. marcescens was also done. Characterization of PBE was done by separation through column chromatography and identification of active metabolites by gas chromatography -mass spectrometry. The major compounds of active fractions such as hexadecanoic acid, eugenol and phytol were assessed for their anti-QS activity against S. marcescens. Further, the in vitro bioassays such as protease, biofilm and HI quantification were also carried out to confirm the anti-QS and antibiofilm potential of phytol in PBE.

RESULTS: PBE inhibits QS mediated prodigiosin pigment production in S. marcescens, which confirmed its anti-QS potential against S. marcescens. At 500µgml[-1] concentration, PBE significantly inhibited the production of protease, lipase, biofilm and EPS to the level of 71%, 68%, 65% and 43% in S. marcescens, respectively. Further, their antibiofilm efficacy was confirmed through microscopic techniques. In addition, PBE effectively inhibited the hydrophobicity and swarming motility. Additionally, the results of qPCR analysis validated the downregulation of QS genes. Chromatographic techniques the presence of hexadecanoic acid, eugenol and phytol in PBE and the potential bioactive compound with anti-QS activity was identified as phytol. In vitro assays with phytol evidenced the potent inhibition of QS-controlled prodigiosin, protease, biofilm and hydrophobicity in S. marcescens, without exerting any deleterious effect on its growth.

CONCLUSION: This study demonstrates the promising anti-QS and antibiofilm activities of PBE and its active metabolite phytol, and confirms the ethnopharmacological applications of these leaves against S. marcescens infections.}, } @article {pmid27718471, year = {2017}, author = {Ahn, M and Gunasekaran, P and Rajasekaran, G and Kim, EY and Lee, SJ and Bang, G and Cho, K and Hyun, JK and Lee, HJ and Jeon, YH and Kim, NH and Ryu, EK and Shin, SY and Bang, JK}, title = {Pyrazole derived ultra-short antimicrobial peptidomimetics with potent anti-biofilm activity.}, journal = {European journal of medicinal chemistry}, volume = {125}, number = {}, pages = {551-564}, doi = {10.1016/j.ejmech.2016.09.071}, pmid = {27718471}, issn = {1768-3254}, mesh = {Anti-Infective Agents/chemical synthesis/chemistry/pharmacology ; Antimicrobial Cationic Peptides/*chemical synthesis/chemistry/pharmacology ; Bacteria/drug effects ; Biofilms/*drug effects ; Humans ; Macrophages/drug effects ; Microbial Sensitivity Tests ; Microscopy, Electron, Transmission ; Molecular Structure ; Peptidomimetics/chemical synthesis/*chemistry/pharmacology ; Polymerase Chain Reaction ; Pyrazoles/*chemical synthesis/chemistry/pharmacology ; }, abstract = {In this study, we report on the first chemical synthesis of ultra-short pyrazole-arginine based antimicrobial peptidomimetics derived from the newly synthesized N-alkyl/aryl pyrazole amino acids. Through the systematic tuning of hydrophobicity, charge, and peptide length, we identified the shortest peptide Py11 with the most potent antimicrobial activity. Py11 displayed greater antimicrobial activity against antibiotic-resistant bacteria, including MRSA, MDRPA, and VREF, which was approximately 2-4 times higher than that of melittin. Besides its higher selectivity (therapeutic index) toward bacterial cells than LL-37, Py11 showed highly increased proteolytic stability against trypsin digestion and maintained its antimicrobial activity in the presence of physiological salts. Interestingly, Py11 exhibited higher anti-biofilm activity against MDRPA compared to LL-37. The results from fluorescence spectroscopy and transmission electron microscopy (TEM) suggested that Py11 kills bacterial cells possibly by integrity disruption damaging the cell membrane, leading to the cytosol leakage and eventual cell lysis. Furthermore, Py11 displayed significant anti-inflammatory (endotoxin-neutralizing) activity by inhibiting LPS-induced production of nitric oxide (NO) and TNF-α. Collectively, our results suggest that Py11 may serve as a model compound for the design of antimicrobial and antisepsis agents.}, } @article {pmid27717660, year = {2017}, author = {Araújo, D and Henriques, M and Silva, S}, title = {Portrait of Candida Species Biofilm Regulatory Network Genes.}, journal = {Trends in microbiology}, volume = {25}, number = {1}, pages = {62-75}, doi = {10.1016/j.tim.2016.09.004}, pmid = {27717660}, issn = {1878-4380}, mesh = {Biofilms/*growth & development ; Candida/growth & development/*pathogenicity ; Candidiasis/microbiology/*pathology ; Cell Adhesion/*physiology ; Humans ; Hyphae/genetics/*growth & development ; }, abstract = {Most cases of candidiasis have been attributed to Candida albicans, but Candida glabrata, Candida parapsilosis and Candida tropicalis, designated as non-C. albicans Candida (NCAC), have been identified as frequent human pathogens. Moreover, Candida biofilms are an escalating clinical problem associated with significant rates of mortality. Biofilms have distinct developmental phases, including adhesion/colonisation, maturation and dispersal, controlled by complex regulatory networks. This review discusses recent advances regarding Candida species biofilm regulatory network genes, which are key components for candidiasis.}, } @article {pmid27715454, year = {2017}, author = {Singh, N and Patil, A and Prabhune, AA and Raghav, M and Goel, G}, title = {Diverse profiles of N-acyl-homoserine lactones in biofilm forming strains of Cronobacter sakazakii.}, journal = {Virulence}, volume = {8}, number = {3}, pages = {275-281}, pmid = {27715454}, issn = {2150-5608}, mesh = {Acyl-Butyrolactones/*metabolism ; Agrobacterium tumefaciens/drug effects/physiology ; Biofilms/*growth & development ; Biological Assay ; Chromatography, High Pressure Liquid ; Chromobacterium/drug effects/physiology ; Cronobacter sakazakii/metabolism/*physiology ; Mass Spectrometry ; Polysaccharides, Bacterial/metabolism ; *Quorum Sensing ; }, abstract = {The present study investigates the role of quorum sensing (QS) molecules expressed by C. sakazakii in biofilm formation and extracellular polysaccharide expression. The QS signaling was detected using Chromobacterium violaceum 026 and Agrobacterium tumefaciens NTL4(pZLR4) based bioassay. Long chain N-acyl-homoserine lactones (AHLs) with C6- C18 chain length were identified using High Performance Liquid Chromatography and Liquid Chromatography-High Resolution Mass Spectrometry. A higher Specific Biofilm Formation (SBF) index (p < 0.05) with the presence of genes associated with cellulose biosynthesis (bcsA, bcsC and bcsG) was observed in the strains. AHLs and their mechanisms can serve as novel targets for developing technologies to eradicate and prevent biofilm formation by C. sakazakii.}, } @article {pmid27715004, year = {2016}, author = {Nayak, D and Kumari, M and Rajachandar, S and Ashe, S and Thathapudi, NC and Nayak, B}, title = {Biofilm Impeding AgNPs Target Skin Carcinoma by Inducing Mitochondrial Membrane Depolarization Mediated through ROS Production.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {42}, pages = {28538-28553}, doi = {10.1021/acsami.6b11391}, pmid = {27715004}, issn = {1944-8252}, mesh = {*Biofilms ; Metal Nanoparticles ; Mitochondrial Membranes ; Reactive Oxygen Species ; Silver ; }, abstract = {Reactive oxygen species (ROS) are a double-edged sword that possesses both beneficial and harmful effects. Although basic research on skin cancer prevention has undergone a huge transformation, cases of recurrence with higher rates of drug resistance are some of its drawbacks. Therefore, targeting mitochondria by ROS overproduction provides an alternate approach for anticancer therapy. In the present study, green-synthesized silver nanoparticles (AgNPs) were explored for triggering the ROS production in A431 skin carcinoma cells. The synthesized AgNPs were characterized for size, charge, morphology, and phase through high-throughput DLS, Fe-SEM, XRD, and ATR-FTIR techniques. Their physiochemical properties with hemoglobin and blood plasma were screened through hemolysis, hemagglutination assay, and circular dichroism spectroscopy confirmed their nontoxic nature. The AgNPs also exhibited additional efficacy in inhibiting biofilm produced by V. cholerae and B. subtilis, thereby facilitating better applicability in wound-healing biomaterials. The depolarization of mitochondrial membrane potential ΔΨm through excess ROS production was deduced to be the triggering force behind the apoptotic cell death mechanism of the skin carcinoma. Subsequent experimentation through DNA fragmentation, comet tail formation, cell membrane blebbing, and reduced invasiveness potentials through scratch assay confirmed the physiological hallmarks of apoptosis. Thus, depolarizing mitochondrial membrane potential through green-synthesized AgNPs provides an economic, nontoxic, specific approach for targeting skin carcinoma with additional benefits of antibacterial activities.}, } @article {pmid27713737, year = {2016}, author = {Ostrov, I and Harel, A and Bernstein, S and Steinberg, D and Shemesh, M}, title = {Development of a Method to Determine the Effectiveness of Cleaning Agents in Removal of Biofilm Derived Spores in Milking System.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1498}, pmid = {27713737}, issn = {1664-302X}, abstract = {Microbial damages caused by biofilm forming bacteria in the dairy industry are a fundamental threat to safety and quality of dairy products. In order to ensure the optimal level of equipment hygiene in the dairy industry, it is necessary to determine the biofilm removal efficiency of cleaning agents used for cleaning-in-place (CIP) procedures. However, currently there is no standard method available for evaluating and comparing cleaning agents for use in CIP procedures in the dairy industry under realistic conditions. The present study aims to establish a CIP model system to evaluate the effectiveness of cleaning agents in removal of biofilm derived spores from the surfaces of stainless steel which is the predominant substrate in milking equipment on dairy farms. The system is based on Bacillus subtilis spores surrounded with exopolymeric substances produced by bacteria during biofilm formation. The spores applied on sampling plates were mounted on T-junctions protruding 1.5-11-times the milk pipe diameter from the main loop to resemble different levels of cleaning difficulty. The cleaning tests were conducted using commercial alkaline detergents and caustic soda at conditions which are relevant to actual farm environment. The spores removal effect was evaluated by comparing the number of viable spores (attached to sampling plates) before and after cleaning. Evaluation of the cleaning and disinfecting effect of cleaning agents toward biofilm derived spores was further performed, which indicates whether spores elimination effect of an agent is due to killing the spores or removing them from the surfaces of dairy equipment. Moreover, it was established that the presence of extracellular matrix is an important factor responsible for high level of cleaning difficulty characteristic for surface attached spores. In overall, the results of this study suggest that the developed model system simulates actual farm conditions for quantitative evaluation of the effectiveness of cleaning and disinfecting agents and their cleaning and disinfecting effect on removal of biofilm derived spores.}, } @article {pmid27713736, year = {2016}, author = {Du, H and Pang, M and Dong, Y and Wu, Y and Wang, N and Liu, J and Awan, F and Lu, C and Liu, Y}, title = {Identification and Characterization of an Aeromonas hydrophila Oligopeptidase Gene pepF Negatively Related to Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1497}, pmid = {27713736}, issn = {1664-302X}, abstract = {Bacterial biofilms are involved in adaptation to complex environments and are responsible for persistent bacterial infections. Biofilm formation is a highly complex process during which multifarious genes work together regularly. In this study, we screened the EZ-Tn5 transposon mutant library to identify genes involved in biofilm formation of Aeromonas hydrophila. A total of 24 biofilm-associated genes were identified, the majority of which encoded proteins related to cell structure, transcription and translation, gene regulation, growth and metabolism. The mutant strain TM90, in which a gene encoding oligopeptidase F (pepF) was disturbed, showed significant upregulation of biofilm formation compared to the parental strain. The TM90 colony phenotype was smaller, more transparent, and splendent. The adhesive ability of TM90 to HEp-2 cells was significantly increased compared with the parental strain. Fifty percent lethal dose (LD50) determinations in zebrafish demonstrated that the enhanced-biofilm mutant TM90 was highly attenuated relative to the wild-type strain. In conclusion, the pepF gene is demonstrated for the first time to be a negative factor for biofilm formation and is involved in A. hydrophila pathogenicity.}, } @article {pmid27712951, year = {2017}, author = {Arenas, J and Tommassen, J}, title = {Meningococcal Biofilm Formation: Let's Stick Together.}, journal = {Trends in microbiology}, volume = {25}, number = {2}, pages = {113-124}, doi = {10.1016/j.tim.2016.09.005}, pmid = {27712951}, issn = {1878-4380}, mesh = {Biofilms/*growth & development ; DNA, Bacterial/genetics/*metabolism ; DNA-Binding Proteins/*metabolism ; Extracellular Matrix/*metabolism/microbiology ; Humans ; Membrane Proteins/*metabolism ; Meningitis, Meningococcal/microbiology/pathology ; Neisseria meningitidis/genetics/*metabolism ; }, abstract = {Extracellular DNA (eDNA) is an essential constituent of the extracellular matrix of biofilms of many microorganisms. In spite of many studies, it has long remained unclear how exactly eDNA exerts its role in biofilm formation. Here, we describe recent advances that have been made in understanding biofilm formation in the human pathogen Neisseria meningitidis. Several cell-surface-exposed proteins have been identified that bind DNA and other negatively charged polymers, such as heparin, by electrostatic interactions. By virtue of these proteins, eDNA can act as an adhesive that binds the bacteria together. We provide examples that indicate that the mechanism of binding eDNA via DNA/heparin-binding proteins is a conserved feature in biofilms of many different microorganisms, including fungi.}, } @article {pmid27712464, year = {2017}, author = {Roehling, S and Astasov-Frauenhoffer, M and Hauser-Gerspach, I and Braissant, O and Woelfler, H and Waltimo, T and Kniha, H and Gahlert, M}, title = {In Vitro Biofilm Formation on Titanium and Zirconia Implant Surfaces.}, journal = {Journal of periodontology}, volume = {88}, number = {3}, pages = {298-307}, doi = {10.1902/jop.2016.160245}, pmid = {27712464}, issn = {1943-3670}, mesh = {Acid Etching, Dental ; Bacterial Adhesion ; *Biofilms ; Dental Implants/*microbiology ; Dental Plaque/*microbiology ; Humans ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Surface Properties ; Titanium ; Zirconium ; }, abstract = {BACKGROUND: It has been hypothesized that zirconia might have a reduced bacterial adhesion compared with titanium; however, results from experimental studies are rather controversial. The aim of the present study is to compare biofilm formation on zirconia and titanium implant surfaces using an in vitro three-species biofilm and human plaque samples.

METHODS: Experimental disks made of titanium (Ti) or zirconia (ZrO2) with a machined (M) or a sandblasted (SLA) and acid-etched (ZLA) surface topography were produced. An in vitro three-species biofilm or human plaque samples were applied for bacterial adhesion to each type of disk, which after 72 hours of incubation was assessed using an anaerobic flow chamber model.

RESULTS: Zirconia showed a statistically significant reduction in three-species biofilm thickness compared with titanium (ZrO2-M: 8.41 μm; ZrO2-ZLA: 17.47 μm; Ti-M: 13.12 μm; Ti-SLA: 21.97 μm); however, no differences were found regarding three-species-biofilm mass and metabolism. Human plaque analysis showed optical density values of 0.06 and 0.08 for ZrO2-M and ZrO2-ZLA, and values of 0.1 and 0.13 for Ti-M and Ti-SLA, respectively; indicating a statistically significant reduction in human biofilm mass on zirconia compared with titanium. Additionally, zirconia revealed a statistically significant reduction in human plaque thickness (ZrO2-M: 9.04 μm; ZrO2-ZLA: 13.83 μm; Ti-M: 13.42 μm; Ti-SLA: 21.3 μm) but a similar human plaque metabolism compared with titanium.

CONCLUSION: Zirconia implant surfaces showed a statistically significant reduction in human plaque biofilm formation after 72 hours of incubation in an experimental anaerobic flow chamber model compared with titanium implant surfaces.}, } @article {pmid27709903, year = {2016}, author = {Ding, Y and Zhou, Y and Yao, J and Szymanski, C and Fredrickson, J and Shi, L and Cao, B and Zhu, Z and Yu, XY}, title = {In Situ Molecular Imaging of the Biofilm and Its Matrix.}, journal = {Analytical chemistry}, volume = {88}, number = {22}, pages = {11244-11252}, doi = {10.1021/acs.analchem.6b03909}, pmid = {27709903}, issn = {1520-6882}, mesh = {*Biofilms/drug effects ; Chromium/pharmacology ; Microscopy, Fluorescence ; *Molecular Imaging ; Shewanella/*chemistry/metabolism ; Spectrometry, Mass, Secondary Ion ; }, abstract = {Molecular mapping of live biofilms at submicrometer resolution presents a grand challenge. Here, we present the first chemical mapping results of biofilm extracellular polymeric substance (EPS) in biofilms using correlative imaging between super resolution fluorescence microscopy and liquid time-of-flight secondary ion mass spectrometry (TOF-SIMS). Shewanella oneidensis is used as a model organism. Heavy metal chromate (Cr2O7[2-]) anions consisting of chromium Cr(VI) was used as a model environmental stressor to treat the biofilms. Of particular interest, biologically relevant water clusters have been first observed in the biofilms. Characteristic fragments of biofilm matrix components such as proteins, polysaccharides, and lipids can be spatially imaged. Furthermore, characteristic fatty acids (e.g., palmitic acid), quinolone signal, and riboflavin fragments were found to respond after the biofilm is treated with Cr(VI), leading to biofilm dispersal. Significant changes in water clusters and quorum sensing signals indicative of intercellular communication in the aqueous environment were observed, suggesting that they might result in fatty acid synthesis and inhibition of riboflavin production. The Cr(VI) reduction seems to follow the Mtr pathway leading to Cr(III) formation. Our approach potentially opens a new avenue for mechanistic insight of microbial community processes and communications using in situ imaging mass spectrometry and super resolution optical microscopy.}, } @article {pmid27709726, year = {2017}, author = {Klančnik, A and Šikić Pogačar, M and Trošt, K and Tušek Žnidarič, M and Mozetič Vodopivec, B and Smole Možina, S}, title = {Anti-Campylobacter activity of resveratrol and an extract from waste Pinot noir grape skins and seeds, and resistance of Camp. jejuni planktonic and biofilm cells, mediated via the CmeABC efflux pump.}, journal = {Journal of applied microbiology}, volume = {122}, number = {1}, pages = {65-77}, doi = {10.1111/jam.13315}, pmid = {27709726}, issn = {1365-2672}, mesh = {ATP-Binding Cassette Transporters/metabolism ; Animals ; Bacterial Adhesion/drug effects ; Bacterial Proteins/metabolism ; Biofilms/growth & development ; Campylobacter jejuni/*drug effects/growth & development/physiology ; Cell Line ; Drug Resistance, Bacterial ; Epithelial Cells/drug effects ; Humans ; Intestines/cytology ; Microbial Sensitivity Tests ; Plankton ; Polystyrenes ; Resveratrol ; Seeds/chemistry ; Stilbenes/*pharmacology ; Swine ; Vitis/*chemistry ; }, abstract = {AIMS: To define anti-Campylobacter jejuni activity of an extract from waste skins and seeds of Pinot noir grapes (GSS), resveratrol and possible resistance mechanisms, and the influence of these on Camp. jejuni morphology.

METHODS AND RESULTS: Using gene-specific knock-out Camp. jejuni mutants and an efflux pump inhibitor, we showed CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene surface and pig small intestine epithelial (PSI) and human foetal small intestine (H4) cell lines, GSS extract shows an efficient inhibition of adhesion of Camp. jejuni to these abiotic and biotic surfaces.

CONCLUSIONS: Low doses of GSS extract can inhibit Camp. jejuni adhesion to polystyrene surfaces and to PSI and H4 cells, and can thus modulate Camp. jejuni invasion and intracellular survival.

An understanding of the activities of GSS extract and resveratrol as bacterial growth inhibitors and the specific mechanisms of cell accumulation is crucial for our understanding of Camp. jejuni resistance. GSS extract inhibition of Camp. jejuni adhesion to abiotic and biotic surfaces provides a further step towards the application of new innovative strategies to control Campylobacter contamination and infection via the food chain.}, } @article {pmid27708626, year = {2016}, author = {Klug, B and Santigli, E and Westendorf, C and Tangl, S and Wimmer, G and Grube, M}, title = {From Mouth to Model: Combining in vivo and in vitro Oral Biofilm Growth.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1448}, pmid = {27708626}, issn = {1664-302X}, abstract = {Background: Oral biofilm studies based on simplified experimental setups are difficult to interpret. Models are limited mostly by the number of bacterial species observed and the insufficiency of artificial media. Few studies have attempted to overcome these limitations and to cultivate native oral biofilm. Aims: This study aimed to grow oral biofilm in vivo before transfer to a biofilm reactor for ex situ incubation. The in vitro survival of this oral biofilm and the changes in bacterial composition over time were observed. Methods: Six human enamel-dentin slabs embedded buccally in dental splints were used as biofilm carriers. Fitted individually to the upper jaw of 25 non-smoking male volunteers, the splints were worn continuously for 48 h. During this time, tooth-brushing and alcohol-consumption were not permitted. The biofilm was then transferred on slabs into a biofilm reactor and incubated there for 48 h while being nourished in BHI medium. Live/dead staining and confocal laser scanning microscopy were used to observe bacterial survival over four points in time: directly after removal (T0) and after 1 (T1), 24 (T2), and 48 h (T3) of incubation. Bacterial diversity at T0 and T3 was compared with 454-pyrosequencing. Fluorescence in situ hybridization (FISH) was performed to show specific taxa. Survival curves were calculated with a specially designed MATLAB script. Acacia and QIIME 1.9.1 were used to process pyrosequencing data. SPSS 21.0 and R 3.3.1 were used for statistical analysis. Results: After initial fluctuations at T1, survival curves mostly showed approximation of the bacterial numbers to the initial level at T3. Pyrosequencing analysis resulted in 117 OTUs common to all samples. The genera Streptococcus and Veillonella (both Firmicutes) dominated at T0 and T3. They make up two thirds of the biofilm. Genera with lower relative abundance had grown significantly at T3. FISH analysis confirmed the pyrosequencing results, i.e., the predominant staining of Firmicutes. Conclusion: We demonstrate the in vitro survival of native primary oral biofilm in its natural complexity over 48 h. Our results offer a baseline for cultivation studies of native oral biofilms in (phyto-) pharmacological and dental materials research. Further investigations and validation of culturing conditions could also facilitate the study of biofilm-induced diseases.}, } @article {pmid27708625, year = {2016}, author = {Di Domenico, EG and Toma, L and Provot, C and Ascenzioni, F and Sperduti, I and Prignano, G and Gallo, MT and Pimpinelli, F and Bordignon, V and Bernardi, T and Ensoli, F}, title = {Development of an in vitro Assay, Based on the BioFilm Ring Test[®], for Rapid Profiling of Biofilm-Growing Bacteria.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1429}, pmid = {27708625}, issn = {1664-302X}, abstract = {Microbial biofilm represents a major virulence factor associated with chronic and recurrent infections. Pathogenic bacteria embedded in biofilms are highly resistant to environmental and chemical agents, including antibiotics and therefore difficult to eradicate. Thus, reliable tests to assess biofilm formation by bacterial strains as well as the impact of chemicals or antibiotics on biofilm formation represent desirable tools for a most effective therapeutic management and microbiological risk control. Current methods to evaluate biofilm formation are usually time-consuming, costly, and hardly applicable in the clinical setting. The aim of the present study was to develop and assess a simple and reliable in vitro procedure for the characterization of biofilm-producing bacterial strains for future clinical applications based on the BioFilm Ring Test® (BRT) technology. The procedure developed for clinical testing (cBRT) can provide an accurate and timely (5 h) measurement of biofilm formation for the most common pathogenic bacteria seen in clinical practice. The results gathered by the cBRT assay were in agreement with the traditional crystal violet (CV) staining test, according to the κ coefficient test (κ = 0.623). However, the cBRT assay showed higher levels of specificity (92.2%) and accuracy (88.1%) as compared to CV. The results indicate that this procedure offers an easy, rapid and robust assay to test microbial biofilm and a promising tool for clinical microbiology.}, } @article {pmid27708403, year = {2016}, author = {Marinelli, P and Pallares, I and Navarro, S and Ventura, S}, title = {Dissecting the contribution of Staphylococcus aureus α-phenol-soluble modulins to biofilm amyloid structure.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {34552}, pmid = {27708403}, issn = {2045-2322}, mesh = {Amino Acid Sequence ; Amyloid/*chemistry/genetics/metabolism ; Amyloidogenic Proteins/*chemistry/genetics/metabolism ; Bacterial Toxins/*chemistry/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Catechin/*analogs & derivatives/chemistry/isolation & purification/pharmacology ; Cloning, Molecular ; Escherichia coli/genetics/metabolism ; Gene Expression ; Genetic Vectors/chemistry/metabolism ; Hydrophobic and Hydrophilic Interactions ; Protein Isoforms/chemistry/genetics/metabolism ; Recombinant Proteins/chemistry/genetics/metabolism ; Sequence Alignment ; Sequence Homology, Amino Acid ; Staphylococcus aureus/*drug effects/genetics/metabolism/ultrastructure ; Tea/chemistry ; }, abstract = {The opportunistic pathogen Staphylococcus aureus is recognized as one of the most frequent causes of biofilm-associated infections. The recently discovered phenol soluble modulins (PSMs) are small α-helical amphipathic peptides that act as the main molecular effectors of staphylococcal biofilm maturation, promoting the formation of an extracellular fibril structure with amyloid-like properties. Here, we combine computational, biophysical and in cell analysis to address the specific contribution of individual PSMs to biofilm structure. We demonstrate that despite their highly similar sequence and structure, contrary to what it was previously thought, not all PSMs participate in amyloid fibril formation. A balance of hydrophobic/hydrophilic forces and helical propensity seems to define the aggregation propensity of PSMs and control their assembly and function. This knowledge would allow to target specifically the amyloid properties of these peptides. In this way, we show that Epigallocatechin-3-gallate (EGCG), the principal polyphenol in green tea, prevents the assembly of amyloidogenic PSMs and disentangles their preformed amyloid fibrils.}, } @article {pmid27706660, year = {2016}, author = {Chen, W and Liang, J and He, Z and Jiang, W}, title = {Preliminary study on total protein extraction methods from Enterococcus faecalis biofilm.}, journal = {Genetics and molecular research : GMR}, volume = {15}, number = {3}, pages = {}, doi = {10.4238/gmr.15038988}, pmid = {27706660}, issn = {1676-5680}, mesh = {Bacterial Proton-Translocating ATPases/*isolation & purification/metabolism ; *Biofilms ; Electrophoresis, Polyacrylamide Gel ; Enterococcus faecalis/*physiology ; Sonication ; }, abstract = {Enterococcus faecalis is the major pathogen of post-endodontic disease and refractory periapical periodontitis, and recent research on this species has focused on its pathogenicity. E. faecalis most often causes disease in the form of a biofilm, and total protein expression shows a strong association with its virulence. Therefore, the purpose of our study was to explore different methods of extracting the total proteins of the E. faecalis (ATCC 33186 standard strain) biofilm. The total proteins in the biofilm were extracted using an ultrasonication method with varied parameters, including duration, amplitude setting, period, and duty cycle. After the optimal conditions of ultrasonication were determined based on the protein profile from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the total protein content in the biofilm was detected using the bicinchoninic acid assay, Bradford Coomassie brilliant blue assay, and Lowry assay, and the results were compared and analyzed. The parameters for the optimal conditions of ultrasonication were as follows: a processing duration of 2 min, amplitude setting of 20%, and ultrasonication period of 4 s at a 50% duty cycle. The total protein content was 2299.1 mg/dish when measured by the bicinchoninic assay, 3793.8 mg/dish when measured by the Bradford Coomassie brilliant blue assay, and 1858.0 mg/dish when measured by the Lowry assay. These results demonstrate that the Bradford Coomassie brilliant blue assay is a simple and feasible method for use in detecting the total protein content in a bacterial biofilm.}, } @article {pmid27706381, year = {2016}, author = {Weerasekera, MM and Wijesinghe, GK and Jayarathna, TA and Gunasekara, CP and Fernando, N and Kottegoda, N and Samaranayake, LP}, title = {Culture media profoundly affect Candida albicans and Candida tropicalis growth, adhesion and biofilm development.}, journal = {Memorias do Instituto Oswaldo Cruz}, volume = {111}, number = {11}, pages = {697-702}, pmid = {27706381}, issn = {1678-8060}, mesh = {Biofilms/*growth & development ; Candida albicans/*physiology ; Candida tropicalis/*physiology ; *Culture Media ; Humans ; Microscopy, Electron, Scanning ; }, abstract = {As there are sparse data on the impact of growth media on the phenomenon of biofilm development for Candida we evaluated the efficacy of three culture media on growth, adhesion and biofilm formation of two pathogenic yeasts, Candida albicans and Candida tropicalis. The planktonic phase yeast growth, either as monocultures or mixed cultures, in sabouraud dextrose broth (SDB), yeast nitrogen base (YNB), and RPMI 1640 was compared, and adhesion as well as biofilm formation were monitored using MTT and crystal violet (CV) assays and scanning electron microscopy. Planktonic cells of C. albicans, C. tropicalis and their 1:1 co-culture showed maximal growth in SDB. C. albicans/C. tropicalis adhesion was significantly facilitated in RPMI 1640 although the YNB elicited the maximum growth for C. tropicalis. Similarly, the biofilm growth was uniformly higher for both species in RPMI 1640, and C. tropicalis was the slower biofilm former in all three media. Scanning electron microscopy images tended to confirm the results of MTT and CV assay. Taken together, our data indicate that researchers should pay heed to the choice of laboratory culture media when comparing relative planktonic/biofilm growth of Candida. There is also a need for standardisation of biofilm development media so as to facilitate cross comparisons between laboratories.}, } @article {pmid27702426, year = {2016}, author = {Sirijant, N and Sermswan, RW and Wongratanacheewin, S}, title = {Burkholderia pseudomallei resistance to antibiotics in biofilm-induced conditions is related to efflux pumps.}, journal = {Journal of medical microbiology}, volume = {65}, number = {11}, pages = {1296-1306}, doi = {10.1099/jmm.0.000358}, pmid = {27702426}, issn = {1473-5644}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism ; *Biofilms ; Burkholderia pseudomallei/*drug effects/genetics/isolation & purification/physiology ; Ceftazidime/pharmacology ; Doxycycline/pharmacology ; Drug Resistance, Multiple, Bacterial ; Gene Expression Regulation, Bacterial ; Humans ; Melioidosis/microbiology ; Microbial Sensitivity Tests ; }, abstract = {Burkholderia pseudomallei, the causative agent of melioidosis, has been found to increase its resistance to antibiotics when growing as a biofilm. The resistance is related to several mechanisms. One of the possible mechanisms is the efflux pump. Using bioinformatics analysis, it was found that BPSL1661, BPSL1664 and BPSL1665 were orthologous genes of the efflux transporter encoding genes for biofilm-related antibiotic resistance, PA1874-PA1877 genes in Pseudomonas aeruginosa strain PAO1. Expression of selected encoding genes for the efflux transporter system during biofilm formation were investigated. Real-time reverse transcriptase PCR expression of amrB, cytoplasmic membrane protein of AmrAB-OprA efflux transporter encoding gene, was slightly increased, while BPSL1665 was significantly increased during growth of bacteria in biofilm formation. Minimum biofilm inhibition concentration and minimum biofilm eradication concentration (MBEC) of ceftazidime (CTZ), doxycycline (DOX) and imipenem were found to be 2- to 1024-times increased when compared to their MICs for of planktonic cells. Inhibition of the efflux transporter by adding phenylalanine arginine β-napthylamide (PAβN), a universal efflux inhibitor, decreased 2 to 16 times as much as MBEC in B. pseudomallei biofilms with CTZ and DOX. When the intracellular accumulation of antibiotics was tested to reveal the pump inhibition, only the concentrations of CTZ and DOX increased in PAβN treated biofilm. Taken together, these results indicated that BPSL1665, a putative precursor of the efflux pump gene, might be related to the adaptation of B. pseudomallei in biofilm conditions. Inhibition of efflux pumps may lead to a decrease of resistance to CTZ and DOX in biofilm cells.}, } @article {pmid27701503, year = {2016}, author = {Rossi, GN and Sorazabal, AL and Salgado, PA and Squassi, AF and Klemonskis, GL}, title = {Toothbrushing procedure in schoolchildren with no previous formal instruction: variables associated to dental biofilm removal.}, journal = {Acta odontologica latinoamericana : AOL}, volume = {29}, number = {1}, pages = {82-89}, pmid = {27701503}, issn = {1852-4834}, mesh = {*Biofilms ; Child ; Dental Plaque/*microbiology/*prevention & control ; Humans ; Records ; Tooth/*microbiology ; Toothbrushing/*methods ; }, abstract = {The aim of this study was to establish the association between features regarding brushing procedure performed by schoolchildren without previous formal training and the effectiveness of biofilm removal. Out of a population of 8900 6- and 7-year-old schoolchildren in Buenos Aires City, 600 children were selected from schools located in homogeneous risk areas. Informed consent was requested from parents or guardians and formal assent was obtained from children themselves. The final sample consisted of 316 subjects. The following tooth brushing variables were analyzed: toothbrush-gripping, orientation of active part of bristles with respect to the tooth, type of movement applied, brushing both jaws together or separately, including all 6 sextants and duration of brushing. The level of dental biofilm after brushing was determined by O'Leary's index, acceptable cut-off point = 20%. Four calibrated dentists performed observations and clinical examinations. Frequency distribution, central tendency and dispersion measures were calculated. Cluster analyses were performed; proportions of variables for each cluster were compared with Bonferroni's correction and OR was obtained. The most frequent categories were: palm gripping (71.51%); perpendicular orientation (85.8%); horizontal movement (95.6%); separate addressing of jaws (68%) and inclusion of all 6 sextants (50.6%). Mean duration of brushing was 48.78 ± 27.36 seconds. 42.7% of the children achieved an acceptable biofilm level. The cluster with the highest proportion of subjects with acceptable post-brushing biofilm levels (p<0.05) differed significantly from the rest for the variable "inclusion of all 6 sextants in brushing procedure". OR was 2.538 (CI 95% 1.603 - 4.017). Inclusion of all six sextants could be a determinant variable for the removal of biofilm by brushing in schoolchildren, and should be systematized as a component in oral hygiene education.}, } @article {pmid27701473, year = {2016}, author = {Suriyanarayanan, T and Periasamy, S and Lin, MH and Ishihama, Y and Swarup, S}, title = {Flagellin FliC Phosphorylation Affects Type 2 Protease Secretion and Biofilm Dispersal in Pseudomonas aeruginosa PAO1.}, journal = {PloS one}, volume = {11}, number = {10}, pages = {e0164155}, pmid = {27701473}, issn = {1932-6203}, mesh = {Adaptation, Physiological ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Flagellin/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Mutation ; Peptide Hydrolases/*metabolism ; Phosphorylation ; Proteomics/methods ; Pseudomonas aeruginosa/metabolism/*physiology ; Serine/metabolism ; Threonine/metabolism ; Type II Secretion Systems/*metabolism ; }, abstract = {Protein phosphorylation has a major role in controlling the life-cycle and infection stages of bacteria. Proteome-wide occurrence of S/T/Y phosphorylation has been reported for many prokaryotic systems. Previously, we reported the phosphoproteome of Pseudomonas aeruginosa and Pseudomonas putida. In this study, we show the role of S/T phosphorylation of one motility protein, FliC, in regulating multiple surface-associated phenomena of P. aeruginosa PAO1. This is the first report of occurrence of phosphorylation in the flagellar protein, flagellin FliC in its highly conserved N-terminal NDO domain across several Gram negative bacteria. This phosphorylation is likely a well-regulated phenomenon as it is growth phase dependent in planktonic cells. The absence of phosphorylation in the conserved T27 and S28 residues of FliC, interestingly, did not affect swimming motility, but affected the secretome of type 2 secretion system (T2SS) and biofilm formation of PAO1. FliC phosphomutants had increased levels and activities of type 2 secretome proteins. The secretion efficiency of T2SS machinery is associated with flagellin phosphorylation. FliC phosphomutants also formed reduced biofilms at 24 h under static conditions and had delayed biofilm dispersal under dynamic flow conditions, respectively. The levels of type 2 secretome and biofilm formation under static conditions had an inverse correlation. Hence, increase in type 2 secretome levels was accompanied by reduced biofilm formation in the FliC phosphomutants. As T2SS is involved in nutrient acquisition and biofilm dispersal during survival and spread of P. aeruginosa, we propose that FliC phosphorylation has a role in ecological adaptation of this opportunistic environmental pathogen. Altogether, we found a system of phosphorylation that affects key surface related processes such as proteases secretion by T2SS, biofilm formation and dispersal.}, } @article {pmid27699486, year = {2016}, author = {Mounier, R and Kapandji, N and Birnbaum, R and Cook, F and Rodriguez, C and Nebbad, B and Lobo, D and Dhonneur, G}, title = {Biofilm-associated infection: the hidden face of cerebrospinal fluid shunt malfunction.}, journal = {Acta neurochirurgica}, volume = {158}, number = {12}, pages = {2321-2324}, doi = {10.1007/s00701-016-2977-z}, pmid = {27699486}, issn = {0942-0940}, mesh = {*Biofilms ; Cerebrospinal Fluid Shunts/*adverse effects ; Humans ; Hydrocephalus/surgery ; Male ; Prosthesis Failure ; Prosthesis-Related Infections/diagnosis/*microbiology ; Young Adult ; }, abstract = {Diagnosis of cerebrospinal fluid (CSF) shunt infection is difficult. Growing evidence links this pattern to biofilm-associated infections (BAI). Biofilm may explain the indolent development of the infection, and the poor efficiency of traditional microbiologic methods. We report the case of a patient admitted for hydrocephalus associated to CSF shunt malfunction. None of the clinical, serum, or CSF laboratory findings were in favor of an infectious process. Only scanning electron microscopy (SEM) revealed the presence of biofilm. Hence, despite a broad CSF shunt infection definition, some infections could remain undiagnosed by the traditional approach. This study is the first to provide some direct evidence for bacterial biofilm-associated CSF shunt infection.}, } @article {pmid27699220, year = {2016}, author = {Siemens, N and Chakrakodi, B and Shambat, SM and Morgan, M and Bergsten, H and Hyldegaard, O and Skrede, S and Arnell, P and Madsen, MB and Johansson, L and , and Juarez, J and Bosnjak, L and Mörgelin, M and Svensson, M and Norrby-Teglund, A}, title = {Biofilm in group A streptococcal necrotizing soft tissue infections.}, journal = {JCI insight}, volume = {1}, number = {10}, pages = {e87882}, pmid = {27699220}, issn = {2379-3708}, mesh = {Adult ; *Biofilms ; Cells, Cultured ; Fasciitis, Necrotizing/*microbiology ; Fibroblasts/cytology ; Humans ; Keratinocytes/cytology ; Male ; Soft Tissue Infections/*microbiology ; Streptococcal Infections/*pathology ; *Streptococcus pyogenes ; }, abstract = {Necrotizing fasciitis caused by group A streptococcus (GAS) is a life-threatening, rapidly progressing infection. At present, biofilm is not recognized as a potential problem in GAS necrotizing soft tissue infections (NSTI), as it is typically linked to chronic infections or associated with foreign devices. Here, we present a case of a previously healthy male presenting with NSTI caused by GAS. The infection persisted over 24 days, and the surgeon documented the presence of a "thick layer biofilm" in the fascia. Subsequent analysis of NSTI patient tissue biopsies prospectively included in a multicenter study revealed multiple areas of biofilm in 32% of the patients studied. Biopsies associated with biofilm formation were characterized by massive bacterial load, a pronounced inflammatory response, and clinical signs of more severe tissue involvement. In vitro infections of a human skin tissue model with GAS NSTI isolates also revealed multilayered fibrous biofilm structures, which were found to be under the control of the global Nra gene regulator. The finding of GAS biofilm formation in NSTIs emphasizes the urgent need for biofilm to be considered as a potential complicating microbiological feature of GAS NSTI and, consequently, emphasizes reconsideration of antibiotic treatment protocols.}, } @article {pmid27699116, year = {2016}, author = {Weiss, N and Obied, KE and Kalkman, J and Lammertink, RG and van Leeuwen, TG}, title = {Measurement of biofilm growth and local hydrodynamics using optical coherence tomography.}, journal = {Biomedical optics express}, volume = {7}, number = {9}, pages = {3508-3518}, pmid = {27699116}, issn = {2156-7085}, abstract = {We report on localized and simultaneous measurement of biofilm growth and local hydrodynamics in a microfluidic channel using optical coherence tomography. We measure independently with high spatio-temporal resolution the longitudinal flow velocity component parallel to the imaging beam and the transverse flow velocity component perpendicular to the imaging beam. Based on the measured velocities we calculate the shear-rates in the flow channel. We show the relation between the measured biofilm structure and flow velocities as biofilm growth progresses over the course of 48 hours.}, } @article {pmid27698083, year = {2016}, author = {Hufnagel, DA and Evans, ML and Greene, SE and Pinkner, JS and Hultgren, SJ and Chapman, MR}, title = {The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli.}, journal = {Journal of bacteriology}, volume = {198}, number = {24}, pages = {3329-3334}, pmid = {27698083}, issn = {1098-5530}, support = {R01 AI099099/AI/NIAID NIH HHS/United States ; R01 GM118651/GM/NIGMS NIH HHS/United States ; T32 GM008353/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Cyclic AMP/*metabolism ; Cyclic AMP Receptor Protein/genetics/*metabolism ; Escherichia coli Proteins/genetics/*metabolism ; *Gene Expression Regulation, Bacterial ; Promoter Regions, Genetic ; Protein Binding ; Trans-Activators/genetics/*metabolism ; Uropathogenic Escherichia coli/genetics/*physiology ; }, abstract = {The extracellular matrix protects Escherichia coli from immune cells, oxidative stress, predation, and other environmental stresses. Production of the E. coli extracellular matrix is regulated by transcription factors that are tuned to environmental conditions. The biofilm master regulator protein CsgD upregulates curli and cellulose, the two major polymers in the extracellular matrix of uropathogenic E. coli (UPEC) biofilms. We found that cyclic AMP (cAMP) regulates curli, cellulose, and UPEC biofilms through csgD The alarmone cAMP is produced by adenylate cyclase (CyaA), and deletion of cyaA resulted in reduced extracellular matrix production and biofilm formation. The catabolite repressor protein (CRP) positively regulated csgD transcription, leading to curli and cellulose production in the UPEC isolate, UTI89. Glucose, a known inhibitor of CyaA activity, blocked extracellular matrix formation when added to the growth medium. The mutant strains ΔcyaA and Δcrp did not produce rugose biofilms, pellicles, curli, cellulose, or CsgD. Three putative CRP binding sites were identified within the csgD-csgB intergenic region, and purified CRP could gel shift the csgD-csgB intergenic region. Additionally, we found that CRP binded upstream of kpsMT, which encodes machinery for K1 capsule production. Together our work shows that cAMP and CRP influence E. coli biofilms through transcriptional regulation of csgD IMPORTANCE The catabolite repressor protein (CRP)-cyclic AMP (cAMP) complex influences the transcription of ∼7% of genes on the Escherichia coli chromosome (D. Zheng, C. Constantinidou, J. L. Hobman, and S. D. Minchin, Nucleic Acids Res 32:5874-5893, 2004, https://dx.doi.org/10.1093/nar/gkh908). Glucose inhibits E. coli biofilm formation, and ΔcyaA and Δcrp mutants show impaired biofilm formation (D. W. Jackson, J.W. Simecka, and T. Romeo, J Bacteriol 184:3406-3410, 2002, https://dx.doi.org/10.1128/JB.184.12.3406-3410.2002). We determined that the cAMP-CRP complex regulates curli and cellulose production and the formation of rugose and pellicle biofilms through csgD Additionally, we propose that cAMP may work as a signaling compound for uropathogenic E. coli (UPEC) to transition from the bladder lumen to inside epithelial cells for intracellular bacterial community formation through K1 capsule regulation.}, } @article {pmid27697162, year = {2017}, author = {Carpino, S and Randazzo, CL and Pino, A and Russo, N and Rapisarda, T and Belvedere, G and Caggia, C}, title = {Influence of PDO Ragusano cheese biofilm microbiota on flavour compounds formation.}, journal = {Food microbiology}, volume = {61}, number = {}, pages = {126-135}, doi = {10.1016/j.fm.2016.09.006}, pmid = {27697162}, issn = {1095-9998}, mesh = {Animals ; Bacteria/genetics/isolation & purification ; Biodiversity ; *Biofilms ; Cheese/*microbiology ; Colony Count, Microbial ; Food Microbiology ; Lactobacillaceae/genetics/isolation & purification/physiology ; Listeria monocytogenes/genetics/isolation & purification ; *Microbiota/physiology ; Milk/microbiology ; Polymerase Chain Reaction ; Salmonella/genetics/isolation & purification ; Streptococcus thermophilus/genetics/isolation & purification ; *Taste ; Volatile Organic Compounds/analysis/*metabolism ; Wood/microbiology ; }, abstract = {The objectives of the present study were to characterize the biofilm microbiota of 11 different farms (from A to K), producing PDO Ragusano cheese, and to investigate on its ability to generate volatile organic compounds (VOCs) in milk samples inoculated with biofilm and incubated under Ragusano cheese making conditions. The biofilms were subjected to plate counting and PCR/T/DGGE analysis and the VOCs generated in incubated milk samples were evaluated through SmartNose, GC/O, and GC/MS. Streptococcus thermophilus was the dominant species both in biofilms and in incubated milks. Lactobacillus, Lactococcus, Enterococcus and Leuconostoc were also identified. Low levels of Pseudomonas spp. and yeasts counts were detected, whereas coliforms, Listeria monocytogenes and Salmonella spp., were never found. SmartNose and GC/O analyses were able to differentiate incubated milk samples on the basis of the odour compounds, highlighting that samples E and F overlapped and sample C was clearly separated from the others. These results complied with those acquired by GC/MS analysis, that detected in total 20 VOCs. Principal component analysis showed positive correlations (r > 0.6; P < 0.05) between some lactic acid bacteria (LAB) and VOCs: such as Enterococcus hirae with alcohols, Lactococcus lactis, Lactobacillus plantarum, Lactobacillus casei and Lactobacillus delbrueckii with aldehydes, and Lactobacillus fermentum, Lactobacillus helveticus and Lactobacillus hilgardii with ketones. This work demonstrates that biofilm represents an excellent source of LAB biodiversity, which contribute to generate VOCs during the production of PDO Ragusano cheese.}, } @article {pmid27697161, year = {2017}, author = {Teh, AHT and Lee, SM and Dykes, GA}, title = {The influence of dissolved oxygen level and medium on biofilm formation by Campylobacter jejuni.}, journal = {Food microbiology}, volume = {61}, number = {}, pages = {120-125}, doi = {10.1016/j.fm.2016.09.008}, pmid = {27697161}, issn = {1095-9998}, mesh = {Aerobiosis ; Biofilms/*growth & development ; Campylobacter jejuni/growth & development/*physiology ; Culture Media/*chemistry ; *Oxygen ; }, abstract = {Campylobacter jejuni survival in aerobic environments has been suggested to be mediated by biofilm formation. Biofilm formation by eight C. jejuni strains under both aerobic and microaerobic conditions in different broths (Mueller-Hinton (MH), Bolton and Brucella) was quantified. The dissolved oxygen (DO) content of the broths under both incubation atmospheres was determined. Biofilm formation for all strains was highest in MH broth under both incubation atmospheres. Four strains had lower biofilm formation in MH under aerobic as compared to microaerobic incubation, while biofilm formation by the other four strains did not differ under the 2 atm. Two strains had higher biofilm formation under aerobic as compared to microaerobic atmospheres in Bolton broth. Biofilm formation by all other strains in Bolton, and all strains in Brucella broth, did not differ under the 2 atm. Under aerobic incubation DO levels in MH > Brucella > Bolton broth. Under microaerobic conditions levels in MH = Brucella > Bolton broth. Levels of DO in MH and Brucella broth were lower under microaerobic conditions but those of Bolton did not differ under the 2 atm. Experimental conditions and especially the DO of broth media confound previous conclusions drawn about aerobic biofilm formation by C. jejuni.}, } @article {pmid27695030, year = {2017}, author = {Vasu, D and Kumar, PS and Prasad, UV and Swarupa, V and Yeswanth, S and Srikanth, L and Sunitha, MM and Choudhary, A and Sarma, PV}, title = {Phosphorylation of Staphylococcus aureus Protein-Tyrosine Kinase Affects the Function of Glucokinase and Biofilm Formation.}, journal = {Iranian biomedical journal}, volume = {21}, number = {2}, pages = {94-105}, pmid = {27695030}, issn = {2008-823X}, abstract = {BACKGROUND: When Staphylococcus aureus is grown in the presence of high concentration of external glucose, this sugar is phosphorylated by glucokinase (glkA) to form glucose-6-phosphate. This product subsequently enters into anabolic phase, which favors biofilm formation. The presence of ROK (repressor protein, open reading frame, sugar kinase) motif, phosphate-1 and -2 sites, and tyrosine kinase sites in glkA of S. aureus indicates that phosphorylation must regulate the glkA activity. The aim of the present study was to identify the effect of phosphorylation on the function of S. aureus glkA and biofilm formation.

METHODS: Pure glkA and protein-tyrosine kinase (BYK) of S. aureus ATCC 12600 were obtained by fractionating the cytosolic fractions of glkA1 and BYK-1 expressing recombinant clones through nickel metal chelate column. The pure glkA was used as a substrate for BYK and the phosphorylation of glkA was confirmed by treating with reagent A and resolving in SDS-PAGE, as well as staining with reagent A. The kinetic parameters of glkA and phosphorylated glkA were determined spectrophotometrically, and in silico tools were used for validation. S. aureus was grown in brain heart infusion broth, which was supplemented with glucose, and then biofilm units were calculated.

RESULTS: Fourfold elevated glkA activity was observed upon the phosphorylation by BYK. Protein-protein docking analysis revealed that glkA structure docked close to the adenosine triphosphate-binding site of BYK structure corroborating the kinetic results. Further, S. aureus grown in the presence of elevated glucose concentration exhibited an increase in the rate of biofilm formation.

CONCLUSION: The elevated function of glkA is an essential requirement for increased biofilm units in S. aureus, a key pathogenic factor that helps its survival and spread the infection.}, } @article {pmid27694725, year = {2016}, author = {Lira, MC and Givisiez, PE and De Sousa, FG and Magnani, M and De Souza, EL and Spricigo, DA and Gebreyes, WA and De Oliveira, CJ}, title = {Biofilm-forming and antimicrobial resistance traits of staphylococci isolated from goat dairy plants.}, journal = {Journal of infection in developing countries}, volume = {10}, number = {9}, pages = {932-938}, doi = {10.3855/jidc.6714}, pmid = {27694725}, issn = {1972-2680}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacteriological Techniques ; Biofilms/*growth & development ; Dairying ; *Drug Resistance, Bacterial ; *Environmental Microbiology ; Goats ; Hand/*microbiology ; Humans ; Milk/*microbiology ; Polymerase Chain Reaction ; Staphylococcus/drug effects/*isolation & purification/*physiology ; }, abstract = {INTRODUCTION: Biofilm-associated antimicrobial resistance is of increasing importance to the maintenance and spread of foodborne pathogens in the food industry. This study aimed to investigate the ability to form biofilm and the antimicrobial resistance of staphylococci contaminating small-scale goat milk dairy plants.

METHODOLOGY: Sixty isolates were tested for antimicrobial resistance against 20 drugs by the microdilution method. Biofilm-forming traits were assessed by the microtiter plate method (MtP), Congo red agar method (CRA), and icaD gene detection by polymerase chain reaction (PCR).

RESULTS: High antimicrobial resistance to ampicillin (60/60; 100%), penicillin G (21/60; 35%), and erythromycin (15/60; 25%) was observed, but all isolates were susceptible to amoxicillin/K-clavulanate, ceftriaxone, ciprofloxacin, gentamicin, levofloxacin, linezolid, and moxifloxacin. No resistance to oxacillin or vancomycin was seen among Staphylococcus aureus. Twenty-seven isolates (27/60; 45%) were considered to form biofilm according to MtP, and similar biofilm-producing frequencies were observed in coagulase-negative staphylococci (CoNS) (20/44; 45.4%) and S. aureus (7/16; 43.7%). The icaD gene was observed only in S. aureus isolates. There was no association between biofilm production and antimicrobial resistance. A higher frequency of biofilm-producing staphylococci was found in isolates from bulk tank milk and hand swabs. On the other hand, isolates from pasteurized milk showed lower frequency of biofilm formation.

CONCLUSIONS: Staphylococci contaminating goat dairy plants are potential biofilm producers. The results suggest no association between the ability to form biofilm and antimicrobial resistance.}, } @article {pmid27694061, year = {2016}, author = {Ojima, Y and Nunogami, S and Taya, M}, title = {Antibiofilm effect of warfarin on biofilm formation of Escherichia coli promoted by antimicrobial treatment.}, journal = {Journal of global antimicrobial resistance}, volume = {7}, number = {}, pages = {102-105}, doi = {10.1016/j.jgar.2016.08.003}, pmid = {27694061}, issn = {2213-7173}, mesh = {Ampicillin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Escherichia coli/*drug effects ; Escherichia coli Infections ; Lactoferrin/pharmacology ; Microbial Sensitivity Tests ; Warfarin/*pharmacology ; }, abstract = {Enhancement of microbial biofilm formation by low antimicrobial doses is a critical problem in the medical field. The objective of this study was to propose a new drug candidate against the biofilm formation promoted by subinhibitory dose of antimicrobials. To determine the effect on biofilm formation of Escherichia coli, a subinhibitory concentration of lactoferrin (LF), a milk protein involved in a broad range of biological properties including antimicrobial action, or ampicillin (AMP), a typical antibiotic, was added to an E. coli cell culture in a 96-well microtiter plate. On the other hand, warfarin (WARF), an oral anticoagulant, or polymyxin B (PMB), a strong antibiotic for biofilm treatment, was added as an antagonist against the biofilm promoted by LF or AMP. The amount of biofilm formed at 100μg/mL LF in lysogeny broth medium was four times higher than in the absence of LF. Meanwhile, it was found that WARF suppressed the LF-promoted biofilm formation to a level comparable with the LF-free condition. WARF worked in a similar manner to PMB, which is known as an antibiofilm agent. Furthermore, WARF could also suppress the biofilm promoted by AMP. In conclusion, this study suggests that WARF can work as an antibiofilm agent against the biofilm formation promoted by subinhibitory dose of antimicrobials.}, } @article {pmid27692715, year = {2016}, author = {Jindal, S and Anand, S and Huang, K and Goddard, J and Metzger, L and Amamcharla, J}, title = {Evaluation of modified stainless steel surfaces targeted to reduce biofilm formation by common milk sporeformers.}, journal = {Journal of dairy science}, volume = {99}, number = {12}, pages = {9502-9513}, doi = {10.3168/jds.2016-11395}, pmid = {27692715}, issn = {1525-3198}, mesh = {Animals ; Bacterial Adhesion ; *Biofilms ; Milk ; Polytetrafluoroethylene ; *Stainless Steel ; }, abstract = {The development of bacterial biofilms on stainless steel (SS) surfaces poses a great threat to the quality of milk and other dairy products as the biofilm-embedded bacteria can survive thermal processing. Established biofilms offer cleaning challenges because they are resistant to most of the regular cleaning protocols. Sporeforming thermoduric organisms entrapped within biofilm matrix can also form heat-resistant spores, and may result in a long-term persistent contamination. The main objective of this study was to evaluate the efficacy of different nonfouling coatings [AMC 18 (Advanced Materials Components Express, Lemont, PA), Dursan (SilcoTek Corporation, Bellefonte, PA), Ni-P-polytetrafluoroethylene (PTFE, Avtec Finishing Systems, New Hope, MN), and Lectrofluor 641 (General Magnaplate Corporation, Linden, NJ)] on SS plate heat exchanger surfaces, to resist the formation of bacterial biofilms. It was hypothesized that modified SS surfaces would promote a lesser amount of deposit buildup and bacterial adhesion as compared with the native SS surface. Vegetative cells of aerobic sporeformers, Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599), were used to study biofilm development on the modified and native SS surfaces. The adherence of these organisms, though influenced by surface energy and hydrophobicity, exhibited no apparent relation with surface roughness. The Ni-P-PTFE coating exhibited the least bacterial attachment and milk solid deposition, and hence, was the most resistant to biofilm formation. Scanning electron microscopy, which was used to visualize the extent of biofilm formation on modified and native SS surfaces, also revealed lower bacterial attachment on the Ni-P-PTFE as compared with the native SS surface. This study thus provides evidence of reduced biofilm formation on the modified SS surfaces.}, } @article {pmid27690310, year = {2016}, author = {Jewell, KS and Falås, P and Wick, A and Joss, A and Ternes, TA}, title = {Transformation of diclofenac in hybrid biofilm-activated sludge processes.}, journal = {Water research}, volume = {105}, number = {}, pages = {559-567}, pmid = {27690310}, issn = {1879-2448}, mesh = {Biofilms ; *Diclofenac ; *Sewage ; Wastewater ; Water Pollutants, Chemical ; }, abstract = {The biotransformation of diclofenac during wastewater treatment was investigated. Attached growth biomass from a carrier-filled compartment of a hybrid-MBBR at the wastewater treatment plant (WWTP) in Bad Ragaz, Switzerland was used to test the biotransformation. Laboratory-scale incubation experiments were performed with diclofenac and carriers and high-resolution LC-QTof-MS was implemented to monitor the biotransformation. Up to 20 diclofenac transformation products (TPs) were detected. Tentative structures were proposed for 16 of the TPs after characterization by MS[2] fragmentation and/or inferring the structure from the transformation pathway and the molecular formula given by the high resolution ionic mass. The remaining four TPs were unambiguously identified via analytical reference standards. The postulated reactions forming the TPs were: hydroxylation, decarboxylation, oxidation, amide formation, ring-opening and reductive dechlorination. Incubation experiments of individual TPs, those which were available as reference standards, provided a deeper look into the transformation pathways. It was found that the transformation consists of four main pathways but no pathway accounted for a clear majority of the transformation. A 10-day monitoring campaign of the full-scale plant confirmed an 88% removal of diclofenac (from approximately 1.6 μg/L in WWTP influent) and the formation of TPs as found in the laboratory was observed. One of the TPs, N-(2,6-dichlorophenyl)-2-indolinone detected at concentrations of around 0.25 μg/L in WWTP effluent, accounting for 16% of the influent diclofenac concentration. The biotransformation of carriers was compared to a second WWTP not utilising carriers. It was found that in contact with activated sludge, similar hydroxylation and decarboxylation reactions occurred but at much slower rates, whereas some reactions, e.g. reductive dechlorination, were not detected at all. Finally, incubation experiments were performed with attached growth biomass from a third WWTP with a similar process configuration to Bad Ragaz WWTP. A similarly effective removal of diclofenac was found with a similar presence of TPs.}, } @article {pmid27689418, year = {2017}, author = {Chen, W and Liang, J and He, Z and Jiang, W}, title = {Differences in the chemical composition of Enterococcus faecalis biofilm under conditions of starvation and alkalinity.}, journal = {Bioengineered}, volume = {8}, number = {1}, pages = {1-7}, pmid = {27689418}, issn = {2165-5987}, mesh = {Bacterial Proteins/chemistry ; *Biofilms ; Culture Media/chemistry ; Enterococcus faecalis/*chemistry/*growth & development ; Hydrogen-Ion Concentration ; Polysaccharides, Bacterial/chemistry ; }, abstract = {ABSTACT This study aimed to investigate the dynamic changes that occur in the chemical composition of an Enterococcus faecalis (E. faecalis) biofilm under conditions of starvation and in an alkaline environment and to explore the function of chemical composition changes in the resistance of the E. faecalis biofilm to an extreme environment. This study established an in vitro E. faecalis biofilm model under starvation and in an alkaline environment. During the formation of the biofilm, the pH value and nutritional condition of the culture medium were changed, and the changes in chemical composition were observed using biochemical measures. The results showed that, when the pH value of the culture medium was 11, the percentage of water-insoluble polysaccharides in the biofilm was significantly lower than under other conditions. In addition, the percentage of water-soluble polysaccharides in culture medium with pH values of 9 and 11 gradually decreased. The level of the water-soluble polysaccharides in each milligram of dry weight of biofilm at pH 11 increased compared to that under other conditions. The results from this study indicate that the chemical composition of E. faecalis biofilm changed in extreme environments. These changes served as a defensive mechanism for E. faecalis against environmental pressures.}, } @article {pmid27688422, year = {2016}, author = {Toljan, I and Bago, I and Jurič, and Anić, I}, title = {Eradication of Intracanal Enterococcus Faecalis Biofilm by Passive Ultrasonic Irrigation and RinsEndo System.}, journal = {Acta stomatologica Croatica}, volume = {50}, number = {1}, pages = {14-22}, pmid = {27688422}, issn = {0001-7019}, abstract = {AIM: The aim of the study was to compare the antimicrobial efficacy of three irrigation techniques after the use of standardized volume of NaOCl and with standardized time and irrigation.

METHODOLOGY: Forty-eight single rooted teeth were inoculated with an Enterococcus faecalis suspension for 24 h. The remaining six canals served as negative controls. The 36 root canals were randomly distributed into three experimental groups; group 1, conventional syringe irrigation; group 2, automated-dynamic irrigation (RinsEndo); group 3, passive ultrasonic irrigation (PUI). In the first protocol, the standardized volume of 3% NaOCl (20 mL) was used and in the second protocol, and standardized irrigation time (45 seconds) was used. Samples from root canals were cultured and the colony-forming units (CFUs) were counted.

RESULTS: When the volume of the irrigant was standardized, RinsEndo was more effective than PUI (p<0.01). When the irrigation time was standardized, there were no significant differences between any irrigation techniques (p>0.05). The RinsEndo group had the highest percentage of minimal counts of E. faecalis CFUs.

CONCLUSIONS: RinsEndo was more effective than PUI only when the volume of the irrigant was standardized. However, the RinsEndo provided higher bacterial reduction in both protocols when using the least amount of the irrigant and providing longer contact time.}, } @article {pmid27686721, year = {2016}, author = {Barca, C and Ranava, D and Bauzan, M and Ferrasse, JH and Giudici-Orticoni, MT and Soric, A}, title = {Fermentative hydrogen production in an up-flow anaerobic biofilm reactor inoculated with a co-culture of Clostridium acetobutylicum and Desulfovibrio vulgaris.}, journal = {Bioresource technology}, volume = {221}, number = {}, pages = {526-533}, doi = {10.1016/j.biortech.2016.09.072}, pmid = {27686721}, issn = {1873-2976}, mesh = {Anaerobiosis ; Bacteria, Anaerobic/metabolism ; *Biofilms ; Bioreactors/*microbiology ; Clostridium acetobutylicum/*metabolism ; Coculture Techniques ; Desulfovibrio vulgaris/*metabolism ; Fermentation ; Glucose/metabolism ; Hydrogen/*metabolism ; }, abstract = {Dark fermentation systems often show low H2 yields and unstable H2 production, as the result of the variability of microbial dynamics and metabolic pathways. Recent batch investigations have demonstrated that an artificial consortium of two anaerobic bacteria, Clostridium acetobutylicum and Desulfovibrio vulgaris Hildenborough, may redirect metabolic fluxes and improve H2 yields. This study aimed at evaluating the scale-up from batch to continuous H2 production in an up-flow anaerobic packed-bed reactor (APBR) continuously fed with a glucose-medium. The effects of various parameters, including void hydraulic retention time (HRTv), pH, and alkalinity, on H2 production performances and metabolic pathways were investigated. The results demonstrated that a stable H2 production was reached after 3-4days of operation. H2 production rates increased significantly with decreasing HRTv from 4 to 2h. Instead, H2 yields remained almost stable despite the change in HRTv, indicating that the decrease in HRTv did not affect the global metabolism.}, } @article {pmid27685978, year = {2016}, author = {Ji, B and Wei, T and Chen, W and Fan, J and Wang, J and Zhu, L and Yang, K}, title = {Optimization of operation conditions for domestic sewage treatment using a sequencing batch biofilm filter.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {6}, pages = {1492-1498}, doi = {10.2166/wst.2016.337}, pmid = {27685978}, issn = {0273-1223}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Nitrogen/analysis ; Oxygen ; Phosphorus/analysis ; *Sewage ; Temperature ; *Waste Disposal Facilities ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; Water Pollutants, Chemical/chemistry ; Water Purification ; }, abstract = {A sequencing batch biofilm filter (SBBF) was applied to treat domestic sewage. The bioreactor consisted of fibrous filler in the upper part and ceramsite filter media in the lower part. The impacts of the most important factors including dissolved oxygen (DO), water temperature and hydraulic retention time (HRT) were evaluated on contaminants removal during the operation of the SBBF. Changes in DO (1.5-4.0 mg/L) and water temperature (2-30 °C) had little effect on the removal of chemical oxygen demand (COD), but had a greater impact on the removal of total nitrogen (TN) and NH4[+]-N. Changes in HRT (8-14 h) had little effect on the removal of COD, but had a greater impact on the removal of TN, NH4[+]-N and total phosphorus. The optimal operating parameters for the SBBF were as follows: DO of 2-3 mg/L, water temperature above 10 °C, and HRT of 10-13 h. Furthermore, a simple kinetic model was developed, reflecting the relationship between COD and HRT.}, } @article {pmid27685086, year = {2016}, author = {Mitchell, KF and Zarnowski, R and Andes, DR}, title = {Fungal Super Glue: The Biofilm Matrix and Its Composition, Assembly, and Functions.}, journal = {PLoS pathogens}, volume = {12}, number = {9}, pages = {e1005828}, pmid = {27685086}, issn = {1553-7374}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; }, } @article {pmid27684212, year = {2017}, author = {Singh, BN and Prateeksha, and Upreti, DK and Singh, BR and Defoirdt, T and Gupta, VK and De Souza, AO and Singh, HB and Barreira, JC and Ferreira, IC and Vahabi, K}, title = {Bactericidal, quorum quenching and anti-biofilm nanofactories: a new niche for nanotechnologists.}, journal = {Critical reviews in biotechnology}, volume = {37}, number = {4}, pages = {525-540}, doi = {10.1080/07388551.2016.1199010}, pmid = {27684212}, issn = {1549-7801}, mesh = {Anti-Bacterial Agents/chemistry/therapeutic use ; Bacteria/*drug effects/pathogenicity ; Bacterial Infections/*drug therapy/microbiology ; Biofilms/drug effects/growth & development ; Humans ; Nanotechnology/*methods/trends ; Quorum Sensing/*drug effects ; }, abstract = {Despite several conventional potent antibacterial therapies, bacterial infections pose a significant threat to human health because they are emerging as the leading cause of death worldwide. Due to the development of antibiotic resistance in bacteria, there is a pressing demand to discover novel approaches for developing more effective therapies to treat multidrug-resistant bacterial strains and biofilm-associated infections. Therefore, attention has been especially devoted to a new and emerging branch of science "nanotechnology" to design non-conventional antimicrobial chemotherapies. A range of nanomaterials and nano-sized carriers for conventional antimicrobial agents have fully justified their potential to combat bacterial diseases by reducing cell viability, by attenuating quorum sensing, and by inhibiting/or eradicating biofilms. This communication summarizes emerging nano-antimicrobial therapies in treating bacterial infections, particularly using antibacterial, quorum quenching, and anti-biofilm nanomaterials as new approaches to tackle the current challenges in combating infectious diseases.}, } @article {pmid27683249, year = {2017}, author = {Zwick, JV and Noble, S and Ellaicy, YK and Coe, GD and Hakey, DJ and King, AN and Sadauskas, AJ and Faulkner, MJ}, title = {AhpA is a peroxidase expressed during biofilm formation in Bacillus subtilis.}, journal = {MicrobiologyOpen}, volume = {6}, number = {1}, pages = {}, pmid = {27683249}, issn = {2045-8827}, mesh = {Bacillus subtilis/genetics/*growth & development/metabolism ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; DNA Damage/genetics ; DNA-Binding Proteins/*metabolism ; Hydrogen Peroxide/metabolism ; Oxidative Stress/physiology ; Peroxidases/genetics/metabolism ; Spores, Bacterial/*growth & development ; Transcription Factors/*metabolism ; }, abstract = {Organisms growing aerobically generate reactive oxygen species such as hydrogen peroxide. These reactive oxygen molecules damage enzymes and DNA, potentially causing cell death. In response, Bacillus subtilis produces at least nine potential peroxide-scavenging enzymes; two belong to the alkylhydroperoxide reductase (Ahp) class of peroxidases. Here, we explore the role of one of these Ahp homologs, AhpA. While previous studies demonstrated that AhpA can scavenge peroxides and thus defend cells against peroxides, they did not clarify when during growth the cell produces AhpA. The results presented here show that the expression of ahpA is regulated in a manner distinct from that of the other peroxide-scavenging enzymes in B. subtilis. While the primary Ahp, AhpC, is expressed during exponential growth and stationary phase, these studies demonstrate that the expression of ahpA is dependent on the transition-state regulator AbrB and the sporulation and biofilm formation transcription factor Spo0A. Furthermore, these results show that ahpA is specifically expressed during biofilm formation, and not during sporulation or stationary phase, suggesting that derepression of ahpA by AbrB requires a signal other than those present upon entry into stationary phase. Despite this expression pattern, ahpA mutant strains still form and maintain robust biofilms, even in the presence of peroxides. Thus, the role of AhpA with regard to protecting cells within biofilms from environmental stresses is still uncertain. These studies highlight the need to further study the Ahp homologs to better understand how they differ from one another and the unique roles they may play in oxidative stress resistance.}, } @article {pmid27682847, year = {2016}, author = {Pavlović, B and Božić, DD and Milovanović, J and Jotić, A and Djukić, V and Djukić, S and Konstantinović, N and Ćirković, I}, title = {Quantification of biofilm formation on silicone intranasal splints: An in vitro study.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {63}, number = {3}, pages = {301-311}, doi = {10.1556/030.63.2016.006}, pmid = {27682847}, issn = {1217-8950}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Moraxella catarrhalis/drug effects/*physiology ; Nose/*microbiology ; Silicones/analysis ; Splints/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/*physiology ; }, abstract = {OBJECTIVES: Biofilms are associated with persistent infections and resistant to conventional therapeutic strategies. The aim of this study was to investigate the quantity of biofilm produced on silicone intranasal splints.

METHODS: Quantity of biofilm formation on silicone splints (SS) was tested on 15 strains of Staphylococcus aureus and Moraxella catarrhalis, respectively. Antimicrobial susceptibility testing was performed in accordance with European Committee on Antimicrobial Susceptibility Testing recommendations.

RESULTS: All tested strains formed different amounts of biofilm on SS: 66.7% S. aureus and 93.3% M. catarrhalis were weak biofilm producers and 33.3% S. aureus and 6.7% M. catarrhalis were moderate biofilm producers. S. aureus formed significantly higher quantity of biofilm compared with M. catarrhalis (p < 0.05). Multidrug resistant S. aureus produced significantly higher amount of biofilm compared with non-multidrug resistant strains (p < 0.05).

CONCLUSION: Quantity of biofilm on SS is highly dependent on bacterial species and their resistance patterns. Future studies are needed to ascertain another therapeutic option for prophylaxis prior to SS placement.}, } @article {pmid27681929, year = {2016}, author = {Salas-Jara, MJ and Ilabaca, A and Vega, M and García, A}, title = {Biofilm Forming Lactobacillus: New Challenges for the Development of Probiotics.}, journal = {Microorganisms}, volume = {4}, number = {3}, pages = {}, pmid = {27681929}, issn = {2076-2607}, abstract = {Probiotics are live bacteria, generally administered in food, conferring beneficial effects to the host because they help to prevent or treat diseases, the majority of which are gastrointestinal. Numerous investigations have verified the beneficial effect of probiotic strains in biofilm form, including increased resistance to temperature, gastric pH and mechanical forces to that of their planktonic counterparts. In addition, the development of new encapsulation technologies, which have exploited the properties of biofilms in the creation of double coated capsules, has given origin to fourth generation probiotics. Up to now, reviews have focused on the detrimental effects of biofilms associated with pathogenic bacteria. Therefore, this work aims to amalgamate information describing the biofilms of Lactobacillus strains which are used as probiotics, particularly L. rhamnosus, L. plantarum, L. reuteri, and L. fermentum. Additionally, we have reviewed the development of probiotics using technology inspired by biofilms.}, } @article {pmid27681928, year = {2016}, author = {Jørgensen, NP and Zobek, N and Dreier, C and Haaber, J and Ingmer, H and Larsen, OH and Meyer, RL}, title = {Streptokinase Treatment Reverses Biofilm-Associated Antibiotic Resistance in Staphylococcus aureus.}, journal = {Microorganisms}, volume = {4}, number = {3}, pages = {}, pmid = {27681928}, issn = {2076-2607}, abstract = {Biofilms formed by Staphylococcus aureus is a serious complication to the use of medical implants. A central part of the pathogenesis relies on S. aureus' ability to adhere to host extracellular matrix proteins, which adsorb to medical implants and stimulate biofilm formation. Being coagulase positive, S. aureus furthermore induces formation of fibrin fibers from fibrinogen in the blood. Consequently, we hypothesized that fibrin is a key component of the extracellular matrix of S. aureus biofilms under in vivo conditions, and that the recalcitrance of biofilm infections can be overcome by combining antibiotic treatment with a fibrinolytic drug. We quantified S. aureus USA300 biofilms grown on peg-lids in brain heart infusion (BHI) broth with 0%-50% human plasma. Young (2 h) and mature (24 h) biofilms were then treated with streptokinase to determine if this lead to dispersal. Then, the minimal biofilm eradication concentration (MBEC) of 24 h old biofilms was measured for vancomycin and daptomycin alone or in combination with 10 µg/mL rifampicin in the presence or absence of streptokinase in the antibiotic treatment step. Finally, biofilms were visualized by confocal laser scanning microscopy. Addition of human plasma stimulated biofilm formation in BHI in a dose-dependent manner, and biofilms could be partially dispersed by streptokinase. The biofilms could be eradicated with physiologically relevant concentrations of streptokinase in combination with rifampicin and vancomycin or daptomycin, which are commonly used antibiotics for treatment of S. aureus infections. Fibronolytic drugs have been used to treat thromboembolic events for decades, and our findings suggest that their use against biofilm infections has the potential to improve the efficacy of antibiotics in treatment of S. aureus biofilm infections.}, } @article {pmid27681927, year = {2016}, author = {Nielsen, SM and Nørskov-Lauritsen, N and Bjarnsholt, T and Meyer, RL}, title = {Achromobacter Species Isolated from Cystic Fibrosis Patients Reveal Distinctly Different Biofilm Morphotypes.}, journal = {Microorganisms}, volume = {4}, number = {3}, pages = {}, pmid = {27681927}, issn = {2076-2607}, abstract = {Achromobacter species have attracted attention as emerging pathogens in cystic fibrosis. The clinical significance of Achromobacter infection is not yet fully elucidated; however, their intrinsic resistance to antimicrobials and ability to form biofilms renders them capable of establishing long-term chronic infections. Still, many aspects of Achromobacter biofilm formation remain uncharacterized. In this study, we characterized biofilm formation in clinical isolates of Achromobacter and investigated the effect of challenging the biofilm with antimicrobials and/or enzymes targeting the extracellular matrix. In vitro biofilm growth and subsequent visualization by confocal microscopy revealed distinctly different biofilm morphotypes: a surface-attached biofilm morphotype of small aggregates and an unattached biofilm morphotype of large suspended aggregates. Aggregates consistent with our in vitro findings were visualized in sputum samples from cystic fibrosis patients using an Achromobacter specific peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) probe, confirming the presence of Achromobacter biofilms in the CF lung. High antibiotic tolerance was associated with the biofilm phenotype, and biocidal antibiotic concentrations were up to 1000 fold higher than for planktonic cultures. Treatment with DNase or subtilisin partially dispersed the biofilm and reduced the tolerance to specific antimicrobials, paving the way for further research into using dispersal mechanisms to improve treatment strategies.}, } @article {pmid27681897, year = {2016}, author = {Lang, JM and Erb, R and Pechal, JL and Wallace, JR and McEwan, RW and Benbow, ME}, title = {Microbial Biofilm Community Variation in Flowing Habitats: Potential Utility as Bioindicators of Postmortem Submersion Intervals.}, journal = {Microorganisms}, volume = {4}, number = {1}, pages = {}, pmid = {27681897}, issn = {2076-2607}, abstract = {Biofilms are a ubiquitous formation of microbial communities found on surfaces in aqueous environments. These structures have been investigated as biomonitoring indicators for stream heath, and here were used for the potential use in forensic sciences. Biofilm successional development has been proposed as a method to determine the postmortem submersion interval (PMSI) of remains because there are no standard methods for estimating the PMSI and biofilms are ubiquitous in aquatic habitats. We sought to compare the development of epinecrotic (biofilms on Sus scrofa domesticus carcasses) and epilithic (biofilms on unglazed ceramic tiles) communities in two small streams using bacterial automated ribosomal intergenic spacer analysis. Epinecrotic communities were significantly different from epilithic communities even though environmental factors associated with each stream location also had a significant influence on biofilm structure. All communities at both locations exhibited significant succession suggesting that changing communities throughout time is a general characteristic of stream biofilm communities. The implications resulting from this work are that epinecrotic communities have distinctive shifts at the first and second weeks, and therefore the potential to be used in forensic applications by associating successional changes with submersion time to estimate a PMSI. The influence of environmental factors, however, indicates the lack of a successional pattern with the same organisms and a focus on functional diversity may be more applicable in a forensic context.}, } @article {pmid27681876, year = {2016}, author = {Li, Y and Cao, S and Zhang, L and Yuan, J and Lau, GW and Wen, Y and Wu, R and Zhao, Q and Huang, X and Yan, Q and Huang, Y and Wen, X}, title = {Absence of TolC Impairs Biofilm Formation in Actinobacillus pleuropneumoniae by Reducing Initial Attachment.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0163364}, pmid = {27681876}, issn = {1932-6203}, abstract = {Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a major cause of economic loss in swine industry worldwide. TolC, the key component of multidrug efflux pumps and type I secretion systems, has been well-studied as an exit duct for numerous substances in many Gram-negative bacteria. By contrast, little is known on the role of TolC in biofilm formation. In this study, a ΔtolC mutant was used to examine the importance of TolC in biofilm formation of A. pleuropneumoniae. Surface attachment assays demonstrated the essential role of TolC in initial attachment of biofilm cells. The loss of TolC function altered surface hydrophobicity, and resulted in greatly reduced autoaggregation in ΔtolC. Using both enzymatic treatments and confocal microscopy, biofilm composition and architecture were characterized. When compared against the wild-type strain, the poly-β-1, 6-N-acetyl-D-glucosamine (PGA), an important biofilm matrix component of A. pleuropneumoniae, was significantly reduced at the initial attachment stage in ΔtolC. These results were confirmed by mRNA level using quantitative RT-PCR. Additionally, defective secretion systems in ΔtolC may also contribute to the deficiency in biofilm formation. Taken together, the current study demonstrated the importance of TolC in the initial biofilm formation stage in A. pleuropneumoniae. These findings could have important clinical implications in developing new treatments against biofilm-related infections by A. pleuropneumoniae.}, } @article {pmid27681588, year = {2016}, author = {Desroche, N and Dropet, C and Janod, P and Guzzo, J}, title = {Antibacterial properties and reduction of MRSA biofilm with a dressing combining polyabsorbent fibres and a silver matrix.}, journal = {Journal of wound care}, volume = {25}, number = {10}, pages = {577-584}, doi = {10.12968/jowc.2016.25.10.577}, pmid = {27681588}, issn = {0969-0700}, mesh = {Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bandages/*microbiology ; Biofilms/*drug effects ; Humans ; Hydrogels/pharmacology/*therapeutic use ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Pseudomonas aeruginosa/drug effects ; Silver Compounds/pharmacology/*therapeutic use ; *Wound Healing ; Wound Infection/*drug therapy/prevention & control ; }, abstract = {OBJECTIVE: This study was designed to evaluate the antibacterial activity of a wound dressing which combines polyacrylate fibres and a silver lipido-colloid matrix (UrgoClean Ag, silver polyabsorbent dressing), against biofilm of methicillin-resistant Staphylococcus aureus (MRSA).

METHOD: Samples of silver polyabsorbent dressing and the neutral form of this dressing (UrgoClean) were applied to biofilms of MRSA formed on a collagen I-coated surface, cultured for 24 hours. Different exposure times were tested (1, 2, 4 and 7 days) without dressing change. The biofilm reduction was quantified by using culture methods and by confocal laser scanning microscopy experiments.

RESULTS: The application of the silver polyabsorbent dressing resulted in a significant decrease of the biofilm population by a log reduction of 4.6, after 24 hours of exposure. Moreover, the antibiofilm activity was maintained for 7 days with reduction values up to 4 log (reduction of biofilm superior to 99.99%). The application of the neutral dressing also induced a significant reduction of the concentration of sessile cells after 1 day (about 0.90 log). The results obtained with this neutral form of the dressing showed that the polyacrylate fibres were able to exert a mechanical disruption of the biofilm architecture.

CONCLUSION: These in vitro experiments demonstrated that silver polyabsorbent dressing was able to strongly reduce the biofilm of MRSA. The antibiofilm mechanism of this dressing can be explained by a dual action of the polyabsorbent fibres (based on ammonium polyacrylate polymer around an acrylic core) which induced a mechanical disruption of the biofilm matrix and/or a sequestration of sessile cells, and the diffusion of silver ions which produced bactericidal activity.

DECLARATION OF INTEREST: This study was supported by Laboratoires Urgo (Dijon). P. Janod is an employee of Laboratoires Urgo. The company had no influence on the experimental design and the interpretation of the results.}, } @article {pmid27680404, year = {2016}, author = {Olsen, I}, title = {Modification of phage for increased antibacterial effect towards dental biofilm.}, journal = {Journal of oral microbiology}, volume = {8}, number = {}, pages = {33089}, pmid = {27680404}, issn = {2000-2297}, } @article {pmid27679782, year = {2016}, author = {Sefidi, MD and Rasooli, I and Owlia, P and Talei, D and Astaneh, SD and Nazarian, S}, title = {Adjuvant role of Pseudomonas flagellin for Acinetobacter baumannii biofilm associated protein.}, journal = {World journal of methodology}, volume = {6}, number = {3}, pages = {190-199}, pmid = {27679782}, issn = {2222-0682}, abstract = {AIM: To study immunogenicity of Pseudomonas N terminal flagellin as an adjuvant for Acinetobacter baumannii (A. baumannii) biofilm associated protein (Bap).

METHODS: The N terminal flagellin gene was amplified. The pET28a (+) and polymerase chain reaction products were digested with HindIII and EcoR I. The ligation of N terminal flagellin into pET28a (‏+) was performed using T4 DNA ligase and was then transformed into Escherichia coli BL21 (DE3) as a suitable expression host. pET28a (‏+) vector harboring a conserved region of Bap from our previous work was used. The recombinant proteins were expressed, analyzed by SDS-PAGE method and was purified by affinity chromatography with His-Tag residues followed by confirmation with western blotting. Mice were immunized with recombinant N terminal flagellin and Bap subunits. The immunized animals were intranasally (i.n) challenged with A. baumannii and Pseudomonas aeruginosa (P. aeruginosa).

RESULTS: The flagellin enhanced the immunogenicity of Bap causing an increase in specific IgG titers in serum (P < 0.001). Internal organs, i.e., liver, lung and spleen of the Bap-Flagellin immunized group challenged with A. baumannii showed significantly lower bacterial load compared to the control group. The bacterial loads were studied in internal organs. A. baumannii infected immunized animals with Bap-Flagellin exhibited internal organs with minor bacterial load while P. aeruginosa PAO1 infected group showed heavy bacterial load of (4.3 ± 0.12) × 10(6), (1.1 ± 0.01) × 10(6) and (2.2 ± 0.22) × 10(6) per gram of lungs, liver and spleen respectively. Bacterial loads were detected per gram of lungs, liver and spleen of the mice group immunized with Bap were (1.2 ± 0.06) × 10(7), (11.1 ± 0.041) × 10(5) and (3.6 ± 0.42) × 10(6) respectively. In vivo neutralization assay indicated that all experimental mice groups, except for Flagellin administered group was significantly (P < 0.05) protected against A. baumannii.

CONCLUSION: These results demonstrate that P. aeruginosa Flagellin as an adjuvant for Bap A. baumannii could be a useful model to evaluate new vaccine against A. baumannii.}, } @article {pmid27676424, year = {2017}, author = {Tall, BD and Chase, HR and Gopinath, GR}, title = {Diverse profiles of N-acyl-homoserine lactones in biofilm forming isolates of Cronobacter sakazakii.}, journal = {Virulence}, volume = {8}, number = {3}, pages = {246-247}, pmid = {27676424}, issn = {2150-5608}, mesh = {*Acyl-Butyrolactones ; Biofilms ; *Cronobacter sakazakii ; Homoserine ; Humans ; Lactones ; Quorum Sensing ; }, } @article {pmid27672214, year = {2017}, author = {Emineke, S and Cooper, AJ and Fouch, S and Birch, BR and Lwaleed, BA}, title = {Diluted honey inhibits biofilm formation: potential application in urinary catheter management?.}, journal = {Journal of clinical pathology}, volume = {70}, number = {2}, pages = {140-144}, doi = {10.1136/jclinpath-2015-203546}, pmid = {27672214}, issn = {1472-4146}, mesh = {Biofilms/*drug effects ; Escherichia coli/*drug effects ; *Honey ; Humans ; Proteus mirabilis/*drug effects ; Urinary Catheters ; }, abstract = {AIMS: Biofilms are ubiquitous and when mature have a complex structure of microcolonies in an extracellular polysaccharide and extracellular DNA matrix. Indwelling medical devices harbour biofilms which have been shown to cause infections and act as reservoirs for pathogens. Urinary catheters are often in place for considerable periods of time and are susceptible to both encrustation and biofilm formation. Strategies for minimising biofilm occurrence underpin an active research area in biomedicine. Manuka honey has, inter alia, well-established antibacterial properties. This study aims to assess the influence of honey on early biofilm formation in an established in vitro model.

METHODS: An established model of early biofilm formation using static bacterial cultures in vinyl 96-well plates was used to grow Escherichia coli, strain ATC 25922 and Proteus mirabilis, strain 7002. Planktonic cells were removed and the residual biofilm was stained with crystal violet, which were subsequently eluted and quantified spectrophotometrically. Manuka honey (Unique Manuka Factor 15+) was added either with the bacteria or up to 72 hours after.

RESULTS: Biofilms in this model was developed over 3 days, after which growth stalled. Mixed (1:1) cultures of E. coli and P. mirabilis grew slower than monocultures. In mixed cultures, honey gave a dose-dependent reduction in biofilm formation (between 3.3 and 16.7%w/v). At 72 hours, all concentrations inhibited maximally (p<0.001). Application of honey to cultures after 24 and 48 hours also reduced the adherent bacterial biomass (p<0.05-p<0.01).

CONCLUSION: Manuka honey at dilutions as low as 3.3% w/v in some protocols and at 10% or above in all protocols tested significantly inhibits bacterial attachment to a vinyl substrate and reduces further early biofilm development. No augmentation of growth over untreated controls was observed in any experiment.}, } @article {pmid27669900, year = {2016}, author = {Dorji, D and Graham, RM and Richmond, P and Keil, A and Mukkur, TK}, title = {Biofilm forming potential and antimicrobial susceptibility of newly emerged Western Australian Bordetella pertussis clinical isolates.}, journal = {Biofouling}, volume = {32}, number = {9}, pages = {1141-1152}, doi = {10.1080/08927014.2016.1232715}, pmid = {27669900}, issn = {1029-2454}, abstract = {Whooping cough caused by Bordetella pertussis is increasing in several countries despite high vaccine coverage. One potential reason for the resurgence is the emergence of genetic variants of the bacterium. Biofilm formation has recently been associated with the pathogenesis of B. pertussis. Biofilm formation of 21 Western Australian B. pertussis clinical isolates was investigated. All isolates formed thicker biofilms than the reference vaccine strain Tohama I while retaining susceptibility to ampicillin, erythromycin, azithromycin and streptomycin. When two biofilm-forming clinical isolates were compared with Tohama I, minimum bactericidal concentrations of antimicrobial agents increased. Isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis revealed significant differences in protein expression in B. pertussis biofilms, providing an opportunity for identification of novel biofilm-associated antigens for incorporation in current pertussis vaccines to improve their protective efficacy. The study also highlights the importance of determining antibiograms for biofilms to formulate improved antimicrobial therapeutic regimens.}, } @article {pmid27669046, year = {2016}, author = {Coscia, MF and Denys, GA and Wack, MF}, title = {Propionibacterium acnes, Coagulase-Negative Staphylococcus, and the "Biofilm-like" Intervertebral Disc.}, journal = {Spine}, volume = {41}, number = {24}, pages = {1860-1865}, pmid = {27669046}, issn = {1528-1159}, mesh = {Adolescent ; Adult ; Aged ; *Biofilms ; Cervical Vertebrae/microbiology/pathology ; Coagulase/metabolism ; Female ; Humans ; Intervertebral Disc/*microbiology/surgery ; Intervertebral Disc Degeneration/microbiology/surgery ; Intervertebral Disc Displacement/microbiology/surgery ; Low Back Pain/complications ; Lumbar Vertebrae/*microbiology/surgery ; Male ; Middle Aged ; Propionibacterium acnes/*isolation & purification ; Young Adult ; }, abstract = {STUDY DESIGN: Patients scheduled for spinal surgery were screened prospectively for a microbial presence associated with intervertebral disc specimens. Inclusion was limited to patients requiring surgery for any of five conditions: study patients with cervical spine intervertebral herniation (IVH), lumbar spine IVH, lumbar spine discogenic pain, and control patients with idiopathic scoliosis/Scheurermann's kyphosis or trauma/neuromuscular deformity. Exclusion criteria included ongoing systemic infection, abnormal pre-operative white cell counts, documented or suspected spinal infection, or previous surgery to the involved disc.

OBJECTIVE: The aim of this study was to test for an association between the presence of a bacterial entity in operated discs and a diagnosis of pathologic disc disease.

SUMMARY OF BACKGROUND DATA: An association has been described between microbial colonization and progressive intervertebral disc degeneration in 36 herniation patients undergoing microdiscectomies. A total of 19 patients had positive cultures on long-term incubation, with Propionibacterium acnes present in 84% of discs.

MATERIALS AND METHODS: Discs were harvested during surgery, using strict sterile technique. Each disc was divided, with half the sample sealed in a sterile, commercially prepared anaerobic culture transport container, and half fixed in formalin. Live specimens were cultured for bacteria at a university-affiliated laboratory in a blinded fashion. Fixed pathologic specimens were gram-stained and read by a board-certified pathologist.

RESULTS: A total of 169 intervertebral discs from 87 patients were evaluated (46 males, 41 females). Positive cultures were noted in 76 of 169 discs (45%), with 34 discs positive for P. acnes and 30 discs positive for Staphylococcus. No pathologic evidence was seen of microorganisms, acute or chronic inflammation, or infection. Pooling the IVH and discogenic pain patients and contrasting them with control patients showed a significant association of IVH with positive bacterial cultures (χ = 15.37; P = 0.000088).

CONCLUSION: Endemic bacterial biofilms are significantly associated with IVH and discogenic pain.

LEVEL OF EVIDENCE: N/A.}, } @article {pmid27667525, year = {2016}, author = {Ishiyama, K and Nakamura, K and Kanno, T and Niwano, Y}, title = {Bactericidal Action of Photodynamic Antimicrobial Chemotherapy (PACT) with Photosensitizers Used as Plaque-Disclosing Agents against Experimental Biofilm.}, journal = {Biocontrol science}, volume = {21}, number = {3}, pages = {187-191}, doi = {10.4265/bio.21.187}, pmid = {27667525}, issn = {1884-0205}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Erythrosine/pharmacology ; Fluoresceins/pharmacology ; *Photochemotherapy ; Photosensitizing Agents/*pharmacology ; Rose Bengal/pharmacology ; Streptococcus mutans/drug effects/physiology/ultrastructure ; }, abstract = {Our previous study revealed that the photo-irradiation of rose bengal, erythrosine, and phloxine, xanthene photosensitizers, used as dental plaque disclosing agents, could exert bactericidal action on planktonic Streptococcus mutans via the singlet oxygen. In the present study, the photo-irradiation induced bactericidal activity of the three xanthene compounds against the experimental biofilm of S. mutans was investigated in combination with acid electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). As a result, only the photo-irradiated rose bengal in AlEW showed prominent bactericidal activity with a >3-log reduction of the viable bacterial count. Since our previous study showed that the affinity of rose bengal to bacterial cells was superior to that of erythrosine and phloxine, it was speculated that AlEW damaged the extracellular matrix of the experimental biofilm, which would let the rose bengal easily be bound to the bacterial cells. From these results, it is strongly suggested that rose bengal is a suitable photosensitizer for use as a plaque disclosing agent in photodynamic antimicrobial chemotherapy to treat dental plaque.}, } @article {pmid27667170, year = {2016}, author = {Makk, J and Tóth, EM and Anda, D and Pál, S and Schumann, P and Kovács, AL and Mádl-Szőnyi, J and Márialigeti, K and Borsodi, AK}, title = {Deinococcus budaensis sp. nov., a mesophilic species isolated from a biofilm sample of a hydrothermal spring cave.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {66}, number = {12}, pages = {5345-5351}, doi = {10.1099/ijsem.0.001519}, pmid = {27667170}, issn = {1466-5034}, mesh = {Bacterial Typing Techniques ; Base Composition ; *Biofilms ; Caves/*microbiology ; DNA, Bacterial/genetics ; DNA, Ribosomal/genetics ; Deinococcus/*classification/isolation & purification/radiation effects ; Fatty Acids/chemistry ; *Gamma Rays ; Glycolipids/chemistry ; Hungary ; Peptidoglycan/chemistry ; Phospholipids/chemistry ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Vitamin K 2/analogs & derivatives/chemistry ; }, abstract = {Following the exposure of a biofilm sample from a hydrothermal spring cave (Gellért Hill, Budapest, Hungary) to gamma radiation, a strain designated FeSTC15-38T was isolated and studied by polyphasic taxonomic methods. The spherical-shaped cells stained Gram-negative, and were aerobic and non-motile. The pH range for growth was pH 6.0-9.0, with an optimum at pH 7.0. The temperature range for growth was 20-37 °C, with an optimum at 28 °C. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. The highest sequence similarities appeared with Deinococcus hopiensis KR-140T (94.1 %), Deinococcus aquaticus PB314T (93.3 %) and Deinococcus aerophilus 5516T-11T (92.7 %). The DNA G+C content of the novel strain was 68.2 mol%. The predominant fatty acids (>10 %) were iso-C16 : 0 and C16 : 1ω7c, and the cell-wall peptidoglycan type was A3β l-Orn-Gly2-3, corroborating the assignment of the strain to the genus Deinococcus. Strain FeSTC15-38T contained MK-8 as the major menaquinone and several unidentified phospholipids, glycolipids and phosphoglycolipids. Resistance to gamma radiation (D10) of strain FeSTC15-38T was <3.0 kGy. According to phenotypic and genotypic data, strain FeSTC15-38T represents a novel species for which the name Deinococcus budaensis sp. nov. is proposed. The type strain is FeSTC15-38T (=NCAIM B.02630T=DSM 101791T).}, } @article {pmid27667095, year = {2016}, author = {Sloup, RE and Cieza, RJ and Needle, DB and Abramovitch, RB and Torres, AG and Waters, CM}, title = {Polysorbates prevent biofilm formation and pathogenesis of Escherichia coli O104:H4.}, journal = {Biofouling}, volume = {32}, number = {9}, pages = {1131-1140}, pmid = {27667095}, issn = {1029-2454}, support = {R01 AI079154/AI/NIAID NIH HHS/United States ; R01 GM109259/GM/NIGMS NIH HHS/United States ; R01 GM110444/GM/NIGMS NIH HHS/United States ; U19 AI090872/AI/NIAID NIH HHS/United States ; }, abstract = {Escherichia coli biotype O104:H4 recently caused the deadliest E. coli outbreak ever reported. Based on prior results, it was hypothesized that compounds inhibiting biofilm formation by O104:H4 would reduce its pathogenesis. The nonionic surfactants polysorbate 80 (PS80) and polysorbate 20 (PS20) were found to reduce biofilms by ≥ 90% at submicromolar concentrations and elicited nearly complete dispersal of preformed biofilms. PS80 did not significantly impact in vivo colonization in a mouse infection model; however, mice treated with PS80 exhibited almost no intestinal inflammation or tissue damage while untreated mice exhibited robust pathology. As PS20 and PS80 are classified as 'Generally Recognized as Safe' (GRAS) compounds by the Food and Drug Administration (FDA), these compounds have clinical potential to treat future O104:H4 outbreaks.}, } @article {pmid27666729, year = {2017}, author = {Qu, Y and Thissen, H and McGiffin, D and Peleg, AY}, title = {Optimizing Microplate Biofilm Assays to Screen Anti-infective Surfaces.}, journal = {Trends in biotechnology}, volume = {35}, number = {1}, pages = {3-5}, doi = {10.1016/j.tibtech.2016.09.001}, pmid = {27666729}, issn = {1879-3096}, mesh = {*Anti-Infective Agents ; *Biofilms ; Humans ; }, } @article {pmid27664053, year = {2016}, author = {Li, E and Wu, J and Wang, P and Zhang, D}, title = {D-Phenylalanine inhibits biofilm development of a marine microbe, Pseudoalteromonas sp. SC2014.}, journal = {FEMS microbiology letters}, volume = {363}, number = {18}, pages = {}, doi = {10.1093/femsle/fnw198}, pmid = {27664053}, issn = {1574-6968}, abstract = {D-Amino acids have been reported to be able to inhibit biofilm formation or disperse existing biofilms of many microbes; in some cases this is due to growth inhibition as an unspecific effect. In this work, six different D-amino acids were tested for their inhibitory effects on biofilm development and bacterial growth of Pseudoalteromonas sp. SC2014, a marine microbe involved in microbiologically influenced corrosion (MIC). Experimental results indicated that D-phenylalanine (D-Phe) inhibited biofilm formation effectively at concentrations that did not affect cell growth, whereas the other D-amino acids either showed little effect or inhibited biofilm formation while inhibiting bacterial growth. Further studies found that D-Phe could inhibit bacterial accumulation on the surface of 316L stainless steel, and prevent bacteria from forming a multilayer biofilm. It was also suggested that D-Phe could promote the disassembly of an established multilayer biofilm but have little effect on the remaining monolayer adherent cells. For the first time, it was found that a D-amino acid could effectively inhibit biofilm formation of an MIC-involved microbe. This might supply a new insight into how MIC could be mitigated.}, } @article {pmid27663615, year = {2016}, author = {Pankajakshan, D and Albuquerque, MT and Evans, JD and Kamocka, MM and Gregory, RL and Bottino, MC}, title = {Triple Antibiotic Polymer Nanofibers for Intracanal Drug Delivery: Effects on Dual Species Biofilm and Cell Function.}, journal = {Journal of endodontics}, volume = {42}, number = {10}, pages = {1490-1495}, pmid = {27663615}, issn = {1878-3554}, support = {K08 DE023552/DE/NIDCR NIH HHS/United States ; UL1 TR001108/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Bacteria/cytology/drug effects ; Biofilms/*drug effects ; Cell Differentiation/drug effects ; Cell Proliferation/drug effects ; Cells, Cultured ; Dental Pulp/cytology/drug effects/microbiology ; Dentin/microbiology ; Disinfection/methods ; Drug Delivery Systems/*methods ; Humans ; Nanofibers/*administration & dosage/chemistry ; Polymers/*administration & dosage ; Root Canal Therapy/methods ; Stem Cells/cytology/drug effects/microbiology ; }, abstract = {INTRODUCTION: Root canal disinfection and the establishment of an intracanal microenvironment conducive to the proliferation/differentiation of stem cells play a significant role in regenerative endodontics. This study was designed to (1) investigate the antimicrobial efficacy of triple antibiotic-containing nanofibers against a dual-species biofilm and (2) evaluate the ability of dental pulp stem cells (DPSCs) to adhere to and proliferate on dentin upon nanofiber exposure.

METHODS: Seven-day-old dual-species biofilm established on dentin specimens was exposed for 3 days to the following: saline (control), antibiotic-free nanofibers (control), and triple antibiotic-containing nanofibers or a saturated triple antibiotic paste (TAP) solution (50 mg/mL in phosphate buffer solution). Bacterial viability was assessed using the LIVE/DEAD assay (Molecular Probes, Inc, Eugene, OR) and confocal laser scanning microscopy. For cytocompatibility studies, dentin specimens after nanofiber or TAP (1 g/mL in phosphate buffer solution) exposure were evaluated for cell adhesion and spreading by actin-phalloidin staining. DPSC proliferation was assessed on days 1, 3, and 7. Statistics were performed, and significance was set at the 5% level.

RESULTS: Confocal laser scanning microscopy showed significant bacterial death upon antibiotic-containing nanofiber exposure, differing significantly (P < .05) from antibiotic-free fibers and the control (saline). DPSCs showed enhanced adhesion/spreading on dentin specimens treated with antibiotic-containing nanofibers when compared with its TAP counterparts. The DPSC proliferation rate was similar on days 1 and 3 in antibiotic-free nanofibers, triple antibiotic-containing nanofibers, and TAP-treated dentin. Proliferation was higher (9-fold) on dentin treated with antibiotic-containing nanofibers on day 7 compared with TAP.

CONCLUSIONS: Triple antibiotic-containing polymer nanofibers led to significant bacterial death, whereas they did not affect DPSC attachment and proliferation on dentin.}, } @article {pmid27662506, year = {2016}, author = {Pires, RH and Cataldi, TR and Franceschini, LM and Labate, MV and Fusco-Almeida, AM and Labate, CA and Palma, MS and Soares Mendes-Giannini, MJ}, title = {Metabolic profiles of planktonic and biofilm cells of Candida orthopsilosis.}, journal = {Future microbiology}, volume = {11}, number = {}, pages = {1299-1313}, doi = {10.2217/fmb-2016-0025}, pmid = {27662506}, issn = {1746-0921}, mesh = {Amino Acids/biosynthesis/genetics ; Biofilms/*growth & development ; Candida/genetics/growth & development/*metabolism/*physiology ; Carbon/metabolism ; Citric Acid Cycle ; Fungal Proteins/biosynthesis/genetics/metabolism/physiology ; Gene Expression Regulation, Fungal/genetics/physiology ; Gene Ontology ; Glucose/metabolism ; Glycogen/metabolism ; Glycolysis ; Metabolic Flux Analysis ; Metabolic Networks and Pathways/genetics/physiology ; Metabolome/genetics/*physiology ; Multigene Family ; Plankton/*growth & development/metabolism/physiology ; Proteome/genetics/metabolism/physiology ; Trehalose/metabolism ; }, abstract = {AIM: This study aims to understand which Candida orthopsilosis protein aids fungus adaptation upon its switching from planktonic growth to biofilm.

MATERIALS & METHODS: Ion mobility separation within mass spectrometry analysis combination were used.

RESULTS: Proteins mapped for different biosynthetic pathways showed that selective ribosome autophagy might occur in biofilms. Glucose, used as a carbon source in the glycolytic flux, changed to glycogen and trehalose.

CONCLUSION: Candida orthopsilosis expresses proteins that combine a variety of mechanisms to provide yeasts with the means to adjust the catalytic properties of enzymes. Adjustment of the enzymes helps modulate the biosynthesis/degradation rates of the available nutrients, in order to control and coordinate the metabolic pathways that enable cells to express an adequate response to nutrient availability.}, } @article {pmid27660778, year = {2016}, author = {Ransom-Jones, E and McDonald, JE}, title = {Draft Genome Sequence of Clostridium sp. Strain W14A Isolated from a Cellulose-Degrading Biofilm in a Landfill Leachate Microcosm.}, journal = {Genome announcements}, volume = {4}, number = {5}, pages = {}, pmid = {27660778}, issn = {2169-8287}, abstract = {Here, we report the draft genome of Clostridium sp. strain W14A, isolated from the anaerobic, cellulolytic biofilm of a cotton string sample incubated in a landfill leachate microcosm. The draft genome comprises 131 contigs, 3,823,510 bp, 51.5% G+C content, and 4,119 predicted coding domain sequences.}, } @article {pmid27660628, year = {2016}, author = {Miljkovic, M and Bertani, I and Fira, D and Jovcic, B and Novovic, K and Venturi, V and Kojic, M}, title = {Shortening of the Lactobacillus paracasei subsp. paracasei BGNJ1-64 AggLb Protein Switches Its Activity from Auto-aggregation to Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1422}, pmid = {27660628}, issn = {1664-302X}, abstract = {AggLb is the largest (318.6 kDa) aggregation-promoting protein of Lactobacillus paracasei subsp. paracasei BGNJ1-64 responsible for forming large cell aggregates, which causes auto-aggregation, collagen binding and pathogen exclusion in vitro. It contains an N-terminus leader peptide, followed by six successive collagen binding domains, 20 successive repeats (CnaB-like domains) and an LPXTG sorting signal at the C-terminus for cell wall anchoring. Experimental information about the roles of the domains of AggLb is currently unknown. To define the domain that confers cell aggregation and the key domains for interactions of specific affinity between AggLb and components of the extracellular matrix, we constructed a series of variants of the aggLb gene and expressed them in Lactococcus lactis subsp. lactis BGKP1-20 using a lactococcal promoter. All of the variants contained a leader peptide, an inter collagen binding-CnaB domain region (used to raise an anti-AggLb antibody), an anchor domain and a different number of collagen binding and CnaB-like domains. The role of the collagen binding repeats of the N-terminus in auto-aggregation and binding to collagen and fibronectin was confirmed. Deletion of the collagen binding repeats II, III, and IV resulted in a loss of the strong auto-aggregation, collagen and fibronectin binding abilities whereas the biofilm formation capability was increased. The strong auto-aggregation, collagen and fibronectin binding abilities of AggLb were negatively correlated to biofilm formation.}, } @article {pmid27660214, year = {2016}, author = {Kvasničková, E and Paulíček, V and Paldrychová, M and Ježdík, R and Maťátková, O and Masák, J}, title = {Aspergillus fumigatus DBM 4057 biofilm formation is inhibited by chitosan, in contrast to baicalein and rhamnolipid.}, journal = {World journal of microbiology & biotechnology}, volume = {32}, number = {11}, pages = {187}, pmid = {27660214}, issn = {1573-0972}, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Aspergillus fumigatus/drug effects/*physiology ; Biofilms/*drug effects ; Chitosan/*pharmacology ; Flavanones/pharmacology ; Glycolipids/pharmacology ; Microbial Sensitivity Tests ; }, abstract = {The biofilms of filamentous-forming fungi are a novel and still insufficiently understood research topic. We have studied Aspergillus fumigatus, an ubiquitous opportunistic pathogenic fungus, as a representative model for a study of biofilm formation by filamentous fungi and for assessing the potential anti-biofilm activity of natural substances. The activity of antibiotic amphotericin B and selected natural substances: baicalein, chitosan and rhamnolipid was studied. The minimum suspension inhibitory concentrations (MIC) were determined and the biofilm susceptibility was investigated by determining the metabolic activity of sessile cells (XTT assay) and total biofilm biomass (crystal violet staining). Significant time-dependent differences in substances' anti-biofilm activity were observed. Images of A. fumigatus biofilm were obtained by Cellavista automatic light microscope and spinning disc confocal microscopy. Baicalein and rhamnolipid were not found as suitable substances for inhibition of the A. fumigatus biofilm formation, as neither of the substances inhibited the sessile cells metabolic activity or the total biofilm biomass even at tenfold MIC after 48 h. In contrast, chitosan at 10 × MIC (25 µg mL[-1]), suppressed the biofilm metabolic activity by 90 % and the total biofilm biomass by 80 % even after 72 h of cultivation. Amphotericin B inhibited only 14 % of total biofilm biomass (crystal violet staining) and 35 % of metabolic activity (XTT assay) of adherent cells under the same conditions. Our results therefore suggest chitosan as potential alternative for treating A. fumigatus biofilm-associated infections.}, } @article {pmid27656070, year = {2016}, author = {Geethapriya, N and Subbiya, A and Padmavathy, K and Mahalakshmi, K and Vivekanandan, P and Sukumaran, VG}, title = {Effect of chitosan-ethylenediamine tetraacetic acid on Enterococcus faecalis dentinal biofilm and smear layer removal.}, journal = {Journal of conservative dentistry : JCD}, volume = {19}, number = {5}, pages = {472-477}, pmid = {27656070}, issn = {0972-0707}, abstract = {OBJECTIVE: The objective of the study was to evaluate the effectiveness of chitosan and chitosan-ethylenediamine tetraacetic acid (EDTA) (3:1,1:1,1:3) in comparison with 5.2% sodium hypochlorite (NaOCl) in disinfecting Enterococcus faecalis biofilm on root canal dentin and in the removal of smear layer with minimal erosion.

MATERIALS AND METHODS: Seventy single-rooted extracted human mandibular premolars (n = 70) were selected for the study. Forty tooth samples were biomechanically prepared, vertically sectioned, and sterilized by autoclaving. The tooth sections were artificially infected with E. faecalis (ATCC 29212 [n = 35] and clinical isolate [SBEF2, n = 35]) to form mature dentinal biofilm in vitro. The tooth samples were treated with the test solutions: chitosan and chitosan-EDTA (3:1, 1:1, 1:3), and the killing time was determined. The smear layer removal ability of the test solutions (Group A: chitosan-EDTA [1:1], Group B: EDTA, Group C: control) (n = 10 tooth/group) was assessed.

RESULTS: Chitosan and chitosan-EDTA (3:1, 1:1, 1:3) exhibited antibacterial activity against both the strains of E. faecalis. Chitosan and chitosan-EDTA caused 3 log reduction in the viable count of the sessile cells of E. faecalis at 15 min while 5.2% NaOCl exhibited 99.98% inhibition at 15 min. Chitosan-EDTA (1:1) was found to be effective in removing the smear layer and showed lesser erosion than EDTA at the coronal and middle portions.

CONCLUSION: Chitosan-EDTA (1:1) is a potential root canal irrigant that performs a dual role - root canal disinfection and smear layer removal.}, } @article {pmid27655385, year = {2016}, author = {Lee, K and Ha, GS and Veeranagouda, Y and Seo, YS and Hwang, I}, title = {A CHASE3/GAF sensor hybrid histidine kinase BmsA modulates biofilm formation and motility in Pseudomonas alkylphenolica.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {11}, pages = {1945-1954}, doi = {10.1099/mic.0.000373}, pmid = {27655385}, issn = {1465-2080}, mesh = {Bacterial Proteins/*chemistry/genetics/*metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Histidine Kinase/*chemistry/genetics/*metabolism ; Protein Domains ; Pseudomonas/chemistry/enzymology/genetics/*physiology ; }, abstract = {Pseudomonas alkylphenolica is an important strain in the biodegradation of toxic alkylphenols and mass production of bioactive polymannuronate polymers. This strain forms a diverse, 3D biofilm architecture, including mushroom-like aerial structures, circular pellicles and surface spreading, depending on culture conditions. A mutagenesis and complementation study showed that a predicted transmembrane kinase, PSAKL28_21690 (1164 aa), harbouring a periplasmic CHASE3 domain flanked by two transmembrane helices in addition to its cytoplasmic GAF, histidine kinase and three CheY-like response regulator domains, plays a positive role in the formation of the special biofilm architecture and a negative role in swimming activity. In addition, the gene, named here as bmsA, is co-transcribed with three genes encoding proteins with CheR (PSAKL28_21700) and CheB (PSAKL28_21710) domains and response regulator and histidine kinase domains (PSAKL28_21720). This gene cluster is thus named bmsABCD and is found widely distributed in pseudomonads and other bacteria. Deletion of the genes in the cluster, except forbmsA, did not result in changes in biofilm-related phenotypes. The RNA-seq analysis showed that the expression of genes coding for flagellar synthesis was increased when bmsA was mutated. In addition, the expression of rsmZ, which is one of final targets of the Gac regulon, was not significantly altered in the bmsA mutant, and overexpression of bmsA in the gacA mutant did not produce the WT phenotype. These results indicate that the sensory Bms regulon does not affect the upper cascade of the Gac signal transduction pathway for the biofilm-related phenotypes in P. alkylphenolica.}, } @article {pmid27654924, year = {2016}, author = {Sancineto, L and Piccioni, M and De Marco, S and Pagiotti, R and Nascimento, V and Braga, AL and Santi, C and Pietrella, D}, title = {Diphenyl diselenide derivatives inhibit microbial biofilm formation involved in wound infection.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {220}, pmid = {27654924}, issn = {1471-2180}, abstract = {BACKGROUND: Organoselenium compounds have antimicrobial activity against some bacteria and fungi; furthermore, the antioxidant activity of diselenides has been demonstrated. The aim of the present work was to examine the in vitro minimal inhibitory concentration of a panel of differently substituted diselenides and their effectiveness in inhibiting biofilm formation and dispersing preformed microbial biofilm of Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa and the yeast Candida albicans, all involved in wound infections. Moreover, the cytotoxicity of the compounds was determined in human dermal fibroblast and keratinocytes. In closing, we tested their direct antioxidant activity.

RESULTS: Diselenides showed different antimicrobial activity, depending on the microorganism. All diselenides demonstrated a good antibiofilm activity against S. aureus and S. epidermidis, the compounds camphor diselenide, bis[ethyl-N-(2'-selenobenzoyl) glycinate] and bis[2'-seleno-N-(1-methyl-2-phenylethyl) benzamide] were active against S. pyogenes and C. albicans biofilm while only diselenides 2,2'-diselenidyldibenzoic acid and bis[ethyl-N-(2'-selenobenzoyl) glycinate] were effective against P. aeruginosa. Moreover, the compounds bis[ethyl-N-(2'-selenobenzoyl) glycinate] and bis[2'-seleno-N-(1-methyl-2-phenylethyl) benzamide] showed an antioxidant activity at concentrations lower than the 50 % of cytotoxic concentration.

CONCLUSIONS: Because microbial biofilms are implicated in chronic infection of wounds and treatment failure, the combination of antimicrobial activity and potential radical scavenging effects may contribute to the improvement of wound healing. Therefore, this study suggests that bis[ethylN-(2'-selenobenzoyl) glycinate] and bis[2'-seleno-N-(1-methyl-2-phenylethyl) benzamide] are promising compounds to be used in preventing and treating microbial wound infections.}, } @article {pmid27653617, year = {2017}, author = {Ryu, SY and Baek, WK and Kim, HA}, title = {Association of biofilm production with colonization among clinical isolates of Acinetobacter baumannii.}, journal = {The Korean journal of internal medicine}, volume = {32}, number = {2}, pages = {345-351}, pmid = {27653617}, issn = {2005-6648}, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/drug effects/*pathogenicity/physiology ; Aged ; Biofilms/*growth & development ; Cross Infection/microbiology ; Drug Resistance, Bacterial ; Female ; Humans ; Male ; Middle Aged ; Republic of Korea ; Virulence ; }, abstract = {BACKGROUND/AIMS: The pathogen Acinetobacter baumannii is increasingly causing healthcare-associated infections worldwide, particularly in intensive care units. Biofilm formation, a factor contributing to the virulence of A. baumannii, is associated with long-term persistence in hospital environments. The present study investigates the clinical impact of biofilm production on colonization and acquisition after patient admission.

METHODS: Forty-nine A. baumannii isolates were obtained between August and November 2013 from Keimyung University Dongsan Medical Center, Daegu, Korea. All isolates were obtained from sputum samples of new patients infected or colonized by A. baumannii. The microtiter plate assay was used to determine biofilm formation.

RESULTS: Twenty-four A. baumannii isolates (48%) demonstrated enhanced biofilm formation capacity than that of the standard A. baumannii strain (ATCC 19606). All isolates were resistant to carbapenem, 38 isolates (77%) were collected from patients in an intensive care unit, and 47 isolates (95%) were from patients who had been exposed to antibiotics in the previous month. The median duration of colonization was longer for biofilm-producing isolates than that of the biofilm non-biofilm producing isolates (18 days vs. 12 days, p < 0.05). Simultaneous colonization with other bacteria was more common for biofilm-producing isolates than that for the non-biofilm producing isolates. The most prevalent co-colonizing bacteria was Staphylococcus aureus.

CONCLUSIONS: Biofilm-producing isolates seem to colonize the respiratory tract for longer durations than the non-biofilm producing isolates. During colonization, biofilm producers promote co-colonization by other bacteria, particularly S. aureus. Additional research is required to determine possible links between biofilm formation and nosocomial infection.}, } @article {pmid27653145, year = {2017}, author = {Jothiprakasam, V and Sambantham, M and Chinnathambi, S and Vijayaboopathi, S}, title = {Candida tropicalis biofilm inhibition by ZnO nanoparticles and EDTA.}, journal = {Archives of oral biology}, volume = {73}, number = {}, pages = {21-24}, doi = {10.1016/j.archoralbio.2016.09.003}, pmid = {27653145}, issn = {1879-1506}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida tropicalis/*drug effects ; Drug Resistance, Fungal ; Edetic Acid/*pharmacology ; Fluconazole/pharmacology ; In Vitro Techniques ; Microscopy, Electron, Transmission ; Nanoparticles ; Zinc Oxide/chemical synthesis/*pharmacology ; }, abstract = {OBJECTIVE: Biofilm of Candida tropicalis denote as a complex cellular congregation with major implication in pathogenesis. This lifestyle of fungus as a biofilm can inhibit immune system and antifungal therapy in treatment of infectious disease especially medical device associated chronic disease. In this study effects of Zinc Oxide (ZnO) nanoparticles and EDTA were evaluated on C. tropicalis biofilm by using different techniques. ZnO nanoparticles were synthesized from Egg albumin.

DESIGN: To assay the formation of biofilm of yeast cells like Fluconazole-susceptible C. tropicalis (ATCC 13,803) and fluconazole-resistant standard strains of C. tropicalis (ATCC 750) were grown in 24 well plates and antifungal effect of ZnO and EDTA were evaluated on C. tropicalis biofilm using ATP bioluminescence and tetrasodium salt (XTT) reduction assays.

RESULTS: Synthesized ZnO NPs and EDTA had effective antifungal properties at the concentration of 5.2, 8.6μg/ml for Fluconazole susceptible strain and 5.42, 10.8μg/ml Fluconazole resistant strains of C. tropicalis biofilms compared to fluconazole drug.

CONCLUSION: In present study we conclude, ZnO considered as a new agent in field of prevention C. tropicalis biofilms especially biofilms formed surface of medical device.}, } @article {pmid27652099, year = {2016}, author = {Ham, Y and Kim, TJ}, title = {Inhibitory activity of monoacylglycerols on biofilm formation in Aeromonas hydrophila, Streptococcus mutans, Xanthomonas oryzae, and Yersinia enterocolitica.}, journal = {SpringerPlus}, volume = {5}, number = {1}, pages = {1526}, pmid = {27652099}, issn = {2193-1801}, abstract = {Biofilm provides a bacterial hiding place by forming a physical barrier and causing physiological changes in cells. The elimination of biofilm is the main goal of hygiene. Chemicals that are inhibitory to biofilm formation have been developed for use in food, personal hygiene products, and medical instruments. Monoacylglycerols are recognized as safe and are used in food as emulsifiers. In this study, the inhibitory activity of monoacylglycerols on bacterial biofilm formation was evaluated systematically with four bacterial strains, Aeromonas hydrophila, Streptococcus mutans, Xanthomonas oryzae, and Yersinia enterocolitica. Monoacylglycerols with two specific lengths of fatty acid moiety, monolaurin and monobehenin, were found to have strong inhibitory activity toward bacterial biofilm formation of S. mutans, X. oryzae, and Y. enterocolitica in a strain specific manner. First, this result suggested that biofilm formation was not inhibited by the detergent characteristics of monoacylglycerols. This suggestion was supported by the inhibitory action of monolaurin on biofilm development but not on the initial cell attachment of Y. enterocolitica in flow cytometric observation. Second, it was also suggested that two distinct response mechanisms to monoacylglycerols existed in bacteria. The existence of these two inhibitory response mechanisms was bacterial strain specific.}, } @article {pmid27648556, year = {2017}, author = {Peralta, MA and da Silva, MA and Ortega, MG and Cabrera, JL and Paraje, MG}, title = {Usnic Acid Activity on Oxidative and Nitrosative Stress of Azole-Resistant Candida albicans Biofilm.}, journal = {Planta medica}, volume = {83}, number = {3-04}, pages = {326-333}, doi = {10.1055/s-0042-116442}, pmid = {27648556}, issn = {1439-0221}, mesh = {Antifungal Agents/isolation & purification/pharmacology ; Antioxidants/pharmacology ; Azoles/*pharmacology ; Bacteria/drug effects ; Benzofurans/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biomass ; Candida albicans/*drug effects/*physiology ; Drug Resistance, Fungal ; Lichens/chemistry/metabolism ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Nitrosation/drug effects ; Oxidation-Reduction/drug effects ; Reactive Oxygen Species/metabolism ; Usnea/chemistry ; }, abstract = {Several studies report that (+)-usnic acid, a lichen secondary metabolite, inhibits growth of different bacteria and fungi; however, the mechanism of its antimicrobial activity remains unknown. In this study, we explored the ability of usnic acid, obtained from Usnea amblyoclada, as an antibiofilm agent against azole-resistant and azole-sensitive Candida albicans strains by studying the cellular stress and antioxidant response in biofilms. The biofilm inhibitory concentration of usnic acid (4 µg/mL) exhibited a significant biofilm inhibition, 71.08 % for azole-resistant and 87.84 % for azole-sensitive C. albicans strains. Confocal scanning laser microscopy showed that the morphology of mature biofilm was altered (reduced the biomass and thickness) in the presence of usnic acid. The antifungal effect was mediated by an oxidative and nitrosative stress, with a significant accumulation of intracellular and extracellular reactive oxygen species detected by confocal scanning laser microscopy and by nitro blue tetrazolium, respectively. In fact, azole-resistant and azole-sensitive C. albicans biofilms treated at the biofilm inhibitory concentration of usnic acid presented 30-fold and 10-fold increased reactive oxygen species measurements compared to basal levels, respectively, and important nitric oxide generation, showing 25-fold and 60-fold increased reactive nitrogen intermediates levels with respect to the controls, respectively. Nonenzymatic and enzymatic antioxidant defenses were increased in both strains compared to biofilm basal levels as response to the increase of oxidant metabolites. The present study shows for the first time that usnic acid can alter the prooxidant-antioxidant balance, which may be the cause of the irreversible cell damage and lead to cell death. Our results suggest that usnic acid could be an alternative for the treatment of Candida infections, which deserves further investigation.}, } @article {pmid27647373, year = {2016}, author = {Patil, PC and Tan, J and Demuth, DR and Luzzio, FA}, title = {1,2,3-Triazole-based inhibitors of Porphyromonas gingivalis adherence to oral streptococci and biofilm formation.}, journal = {Bioorganic & medicinal chemistry}, volume = {24}, number = {21}, pages = {5410-5417}, pmid = {27647373}, issn = {1464-3391}, support = {R01 DE023206/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Porphyromonas gingivalis/*drug effects ; Small Molecule Libraries/chemical synthesis/chemistry/*pharmacology ; Streptococcus gordonii/*drug effects ; Structure-Activity Relationship ; Triazoles/chemical synthesis/chemistry/*pharmacology ; }, abstract = {The development and use of small-molecule inhibitors of the adherence of Porphyromonas gingivalis to oral streptococci represents a potential therapy for the treatment of periodontal disease as these organisms work in tandem to colonize the oral cavity. Earlier work from these laboratories demonstrated that a small synthetic peptide was an effective inhibitor of the interaction between P. gingivalis and Streptococcus gordonii and that a small-molecule peptidomimetic would provide a more stable, less expensive and more effective inhibitor. An array of 2-(azidomethyl)- and 2-(azidophenyl)-4,5-diaryloxazoles having a full range of hydrophobic groups were prepared and reacted with substituted arylacetylenes to afford the corresponding 'click' products. The title compounds were evaluated for their ability to inhibit P. gingivalis' adherence to oral streptococci and several were found to be inhibitory in the range of (IC50) 5.3-67μM.}, } @article {pmid27647148, year = {2016}, author = {Subramanian, S and Gerasopoulos, K and Guo, M and Sintim, HO and Bentley, WE and Ghodssi, R}, title = {Autoinducer-2 analogs and electric fields - an antibiotic-free bacterial biofilm combination treatment.}, journal = {Biomedical microdevices}, volume = {18}, number = {5}, pages = {95}, doi = {10.1007/s10544-016-0120-9}, pmid = {27647148}, issn = {1572-8781}, mesh = {Biofilms/*drug effects ; *Electricity ; Escherichia coli/cytology/*drug effects/*physiology ; Homoserine/*analogs & derivatives/chemistry/pharmacology ; Lab-On-A-Chip Devices ; Lactones/*chemistry/*pharmacology ; Microscopy, Confocal ; Quorum Sensing/drug effects ; }, abstract = {Bacterial biofilms are a common cause of chronic medical implant infections. Treatment and eradication of biofilms by conventional antibiotic therapy has major drawbacks including toxicity and side effects associated with high-dosage antibiotics. Additionally, administration of high doses of antibiotics may facilitate the emergence of antibiotic resistant bacteria. Thus, there is an urgent need for the development of treatments that are not based on conventional antibiotic therapies. Presented herein is a novel bacterial biofilm combination treatment independent of traditional antibiotics, by using low electric fields in combination with small molecule inhibitors of bacterial quorum sensing - autoinducer-2 analogs. We investigate the effect of this treatment on mature Escherichia coli biofilms by application of an alternating and offset electric potential in combination with the small molecule inhibitor for 24 h using both macro and micro-scale devices. Crystal violet staining of the macro-scale biofilms shows a 46 % decrease in biomass compared to the untreated control. We demonstrate enhanced treatment efficacy of the combination therapy using a high-throughput polydimethylsiloxane-based microfluidic biofilm analysis platform. This microfluidic flow cell is designed to reduce the growth variance of in vitro biofilms while providing an integrated control, and thus allows for a more reliable comparison and evaluation of new biofilm treatments on a single device. We utilize linear array charge-coupled devices to perform real-time tracking of biomass by monitoring changes in optical density. End-point confocal microscopy measurements of biofilms treated with the autoinducer analog and electric fields in the microfluidic device show a 78 % decrease in average biofilm thickness in comparison to the negative controls and demonstrate good correlation with real-time optical density measurements. Additionally, the combination treatment showed 76 % better treatment efficacy compared to conventional antibiotic therapy. Taken together these results suggest that the antibiotic-free combination treatment described here may provide an effective alternative to traditional antibiotic therapies against bacterial biofilm infections. Use of this combination treatment in the medical and environmental fields would alleviate side effects associated with high-dosage antibiotic therapies, and reduce the rise of antibiotic-resistant bacteria.}, } @article {pmid27647064, year = {2016}, author = {Tan, Y and Leonhard, M and Ma, S and Schneider-Stickler, B}, title = {Influence of culture conditions for clinically isolated non-albicans Candida biofilm formation.}, journal = {Journal of microbiological methods}, volume = {130}, number = {}, pages = {123-128}, doi = {10.1016/j.mimet.2016.09.011}, pmid = {27647064}, issn = {1872-8359}, mesh = {Batch Cell Culture Techniques/methods ; Biofilms/*growth & development ; Candida/classification/*growth & development/*isolation & purification/metabolism ; Cell Adhesion ; Culture Media/*chemistry ; Humans ; Larynx, Artificial/microbiology ; }, abstract = {Non-albicans Candida species have been isolated in increasing numbers in patients. Moreover, they are adept at forming biofilms. This study analyzed biofilm formation of clinically isolated non-albicans Candida, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, YPD and BHI) and several culture variables (inoculum concentration, incubation period and feeding conditions). The results showed that culture conditions strongly influenced non-albicans Candida species biofilm formation. YPD and BHI resulted in larger amount of biofilm formation with higher metabolic activity of biofilms. Furthermore, the growth media seems to have varying effects on adhesion and biofilm development. Growth conditions may also influence biofilm formation, which was enhanced when starting the culture with a larger inoculum, longer incubation period and using a fed-batch system. Therefore, the potential influences of external environmental factors should be considered when studying the non-albicans Candida biofilms in vitro.}, } @article {pmid27646453, year = {2016}, author = {Zhang, Y and Chen, JX and Wen, LL and Tang, Y and Zhao, HP}, title = {Effects of salinity on simultaneous reduction of perchlorate and nitrate in a methane-based membrane biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {23}, pages = {24248-24255}, pmid = {27646453}, issn = {1614-7499}, mesh = {Biodegradation, Environmental ; Biofilms/*growth & development ; Bioreactors/*microbiology ; Membranes, Artificial ; Methane/*metabolism ; Methanococcus/growth & development/metabolism ; Methylocystaceae/growth & development/metabolism ; Methylomonas/growth & development/metabolism ; Nitrates/*analysis ; Perchlorates/*analysis ; Real-Time Polymerase Chain Reaction ; Salinity ; Water Pollutants, Chemical/*analysis ; Water Purification/*methods ; }, abstract = {This study builds upon prior work showing that methane (CH4) could be utilized as the sole electron donor and carbon source in a membrane biofilm reactor (MBfR) for complete perchlorate (ClO4[-]) and nitrate (NO3[-]) removal. Here, we further investigated the effects of salinity on the simultaneous removal of the two contaminants in the reactor. By testing ClO4[-] and NO3[-] at different salinities, we found that the reactor performance was very sensitive to salinity. While 0.2 % salinity did not significantly affect the hydrogen-based MBfR for ClO4[-] and NO3[-] removals, 1 % salinity completely inhibited ClO4[-] reduction and significantly lowered NO3[-] reduction in the CH4-based MBfR. In salinity-free conditions, NO3[-] and ClO4[-] removal fluxes were 0.171 g N/m[2]-day and 0.091 g/m[2]-day, respectively, but NO3[-] removal fluxes dropped to 0.0085 g N/m[2]-day and ClO4[-] reduction was completely inhibited when the medium changed to 1 % salinity. Scanning electron microscopy (SEM) showed that the salinity dramatically changed the microbial morphology, which led to the development of wire-like cell structures. Quantitative real-time PCR (qPCR) indicated that the total number of microorganisms and abundances of functional genes significantly declined in the presence of NaCl. The relative abundances of Methylomonas (methanogens) decreased from 31.3 to 5.9 % and Denitratisoma (denitrifiers) decreased from 10.6 to 4.4 % when 1 % salinity was introduced.}, } @article {pmid27645982, year = {2016}, author = {Rimoldi, SG and De Vecchi, E and Pagani, C and Zambelli, A and Di Gregorio, A and Bosisio, E and Vanelli, P and Scrofani, R and Gismondo, MR and Cagnoni, G and Antona, C}, title = {Use of Dithiothreitol to Dislodge Bacteria From the Biofilm on an Aortic Valve in the Operating Theatre: A Case of Infective Endocarditis Caused by Staphylococcus aureus and Proteus mirabilis.}, journal = {The Annals of thoracic surgery}, volume = {102}, number = {4}, pages = {e357-9}, doi = {10.1016/j.athoracsur.2016.03.023}, pmid = {27645982}, issn = {1552-6259}, mesh = {Adult ; Aortic Valve/drug effects/*microbiology/surgery ; Biofilms/*drug effects ; Echocardiography, Transesophageal/methods ; Endocarditis, Bacterial/*diagnostic imaging/*drug therapy/etiology/surgery ; Follow-Up Studies ; Humans ; Male ; Operating Rooms ; Proteus mirabilis/*drug effects/physiology ; Risk Assessment ; Staphylococcus aureus/*drug effects/physiology ; Substance-Related Disorders/complications ; Treatment Outcome ; }, abstract = {This is the first reported case of 2 biofilm-producing bacteria, Staphylococcus aureus and Proteus mirabilis, identified from an aortic valve using an innovative device with dithiothreitol solution, able to dislodge bacterial biofilm. The method is usable in the operating theatre and recommended in infective endocarditis nonresponders to empiric therapy.}, } @article {pmid27643392, year = {2016}, author = {Jung, JE and Cai, JN and Cho, SD and Song, KY and Jeon, JG}, title = {Influence of fluoride on the bacterial composition of a dual-species biofilm composed of Streptococcus mutans and Streptococcus oralis.}, journal = {Biofouling}, volume = {32}, number = {9}, pages = {1079-1087}, doi = {10.1080/08927014.2016.1230607}, pmid = {27643392}, issn = {1029-2454}, mesh = {Antibiosis/*drug effects ; Bacterial Load/drug effects ; Biofilms/*drug effects ; Dental Caries/microbiology ; Dose-Response Relationship, Drug ; Fluorides/*pharmacology ; Humans ; Models, Biological ; Streptococcus mutans/*drug effects/growth & development/physiology ; Streptococcus oralis/*drug effects/growth & development/physiology ; }, abstract = {Despite the widespread use of fluoride for the prevention of dental caries, few studies have demonstrated the effects of fluoride on the bacterial composition of dental biofilms. This study investigated whether fluoride affects the proportion of Streptococcus mutans and S. oralis in mono- and dual-species biofilm models, via microbiological, biochemical, and confocal fluorescence microscope studies. Fluoride did not affect the bacterial count and bio-volume of S. mutans and S. oralis in mono-species biofilms, except for the 24-h-old S. mutans biofilms. However, fluoride reduced the proportion and bio-volume of S. mutans but did not decrease those of S. oralis during both S. oralis and S. mutans dual-species biofilm formation, which may be related to the decrease in extracellular polysaccharide formation by fluoride. These results suggest that fluoride may prevent the shift in the microbial proportion to cariogenic bacteria in dental biofilms, subsequently inhibiting the cariogenic bacteria dominant biofilm formation.}, } @article {pmid27642828, year = {2016}, author = {Chen, Y and Zhao, J and Li, K and Xie, S}, title = {A novel fast mass transfer anaerobic inner loop fluidized bed biofilm reactor for PTA wastewater treatment.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {5}, pages = {1088-1095}, doi = {10.2166/wst.2016.285}, pmid = {27642828}, issn = {0273-1223}, mesh = {Anaerobiosis ; Bacteria, Anaerobic/*physiology ; Biofilms/*growth & development ; *Bioreactors ; Phthalic Acids/chemistry/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; }, abstract = {In this paper, a fast mass transfer anaerobic inner loop fluidized bed biofilm reactor (ILFBBR) was developed to improve purified terephthalic acid (PTA) wastewater treatment. The emphasis of this study was on the start-up mode of the anaerobic ILFBBR, the hydraulic loadings and the operation stability. The biological morphology of the anaerobic biofilm in the reactors was also analyzed. The anaerobic column could operate successfully for 46 days due to the pre-aerating process. The anaerobic column had the capacity to resist shock loadings and maintained a high stable chemical oxygen demand (COD) and terephthalic acid removal rates at a hydraulic retention time of 5-10 h, even under conditions of organic volumetric loadings as high as 28.8 kg COD·m(-3).d(-1). The scanning electron microscope analysis of the anaerobic carrier demonstrated that clusters of prokaryotes grew inside of pores and that the filaments generated by pre-aeration contributed to the anaerobic biofilm formation and stability.}, } @article {pmid27639707, year = {2017}, author = {El Haj, C and Murillo, O and Ribera, A and Garcia-Somoza, D and Tubau, F and Cabellos, C and Cabo, J and Ariza, J}, title = {The anti-biofilm effect of macrolides in a rat model of S. aureus foreign-body infection: Might it be of clinical relevance?.}, journal = {Medical microbiology and immunology}, volume = {206}, number = {1}, pages = {31-39}, pmid = {27639707}, issn = {1432-1831}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Clarithromycin/*administration & dosage/pharmacology ; Daptomycin/administration & dosage/pharmacology ; Disease Models, Animal ; Drug Interactions ; Drug Therapy, Combination/methods ; Foreign Bodies/*complications ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Rats ; Rifampin/administration & dosage/pharmacology ; Staphylococcal Infections/*prevention & control ; Staphylococcus aureus/*drug effects/physiology ; Treatment Outcome ; }, abstract = {Using a tissue cage infection rat model, we test the anti-biofilm effect of clarithromycin on the efficacy of daptomycin and a daptomycin + rifampicin combination against methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). In vitro: kill curves, daptomycin exposure studies and clarithromycin activity against biofilm were studied. In vivo: the efficacies of clarithromycin, daptomycin or daptomycin + clarithromycin, daptomycin + rifampicin and daptomycin + rifampicin + clarithromycin combinations were evaluated. In vitro: the addition of clarithromycin to daptomycin improved its activity only against one MRSA strain. Changes in daptomycin MIC values appeared more quickly in MSSA than in MRSA strain, and this was not modified by clarithromycin. Clarithromycin prevented biofilm formation but did not eradicate it. In vivo: the daptomycin + rifampicin combination was the most effective treatment and was not improved by the addition of clarithromycin. Daptomycin and daptomycin + clarithromycin had similar effectiveness; the combination protected against the appearance of daptomycin resistance only in one MRSA strain. Using a staphylococcal foreign-body infection model, we observed a slight effect with the addition of clarithromycin to daptomycin, which resulted in protection against the appearance of daptomycin-resistant strains. However, efficacy was not improved. Overall, our findings do not support a relevant clinical role for macrolides in treating device-related staphylococcal infections based on their anti-biofilm effect.}, } @article {pmid27639235, year = {2016}, author = {Madjarov, J and Prokhorova, A and Messinger, T and Gescher, J and Kerzenmacher, S}, title = {The performance of microbial anodes in municipal wastewater: Pre-grown multispecies biofilm vs. natural inocula.}, journal = {Bioresource technology}, volume = {221}, number = {}, pages = {165-171}, doi = {10.1016/j.biortech.2016.09.004}, pmid = {27639235}, issn = {1873-2976}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms ; Electrodes/*microbiology ; Geobacter/*physiology ; Sewage ; Shewanella/*physiology ; Waste Disposal, Fluid/*instrumentation/methods ; Wastewater ; }, abstract = {In this study, different inoculation strategies for continuously operated microbial anodes are analyzed and compared. After 20daysof operation with municipal wastewater anodes pre-incubated with a biofilm of the exoelectrogenic species Geobacter and Shewanella showed current densities of (65±8) μA/cm[2]. This is comparable to the current densities of non-inoculated anodes and anodes inoculated with sewage sludge. Analysis of the barcoded pre-grown multispecies biofilms reveal that 99% of the original biofilm was detached after 20daysof operation with municipal wastewater. This is in contrast to previous experiments where a pre-grown biofilm of exoelectrogens was operated in batch mode. To implement pre-grown biofilms in continuous systems it will thus be necessary to reveal a window of process parameters in which typical exoelectrogenic microorganisms including model organisms can be kept and/or enriched on anodes.}, } @article {pmid27638458, year = {2017}, author = {Kang, F and Wang, Q and Shou, W and Collins, CD and Gao, Y}, title = {Alkali-earth metal bridges formed in biofilm matrices regulate the uptake of fluoroquinolone antibiotics and protect against bacterial apoptosis.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {220}, number = {Pt A}, pages = {112-123}, doi = {10.1016/j.envpol.2016.09.029}, pmid = {27638458}, issn = {1873-6424}, mesh = {Anti-Bacterial Agents/*metabolism/pharmacokinetics ; Apoptosis/*drug effects ; Biodegradation, Environmental/drug effects ; *Biofilms ; Ciprofloxacin/metabolism/pharmacokinetics ; Escherichia coli/*drug effects/*metabolism ; Fluoroquinolones/*metabolism/pharmacokinetics ; Metals, Alkali/*pharmacology ; }, abstract = {Bacterially extracellular biofilms play a critical role in relieving toxicity of fluoroquinolone antibiotic (FQA) pollutants, yet it is unclear whether antibiotic attack may be defused by a bacterial one-two punch strategy associated with metal-reinforced detoxification efficiency. Our findings help to assign functions to specific structural features of biofilms, as they strongly imply a molecularly regulated mechanism by which freely accessed alkali-earth metals in natural waters affect the cellular uptake of FQAs at the water-biofilm interface. Specifically, formation of alkali-earth-metal (Ca[2+] or Mg[2+]) bridge between modeling ciprofloxacin and biofilms of Escherichia coli regulates the trans-biofilm transport rate of FQAs towards cells (135-nm-thick biofilm). As the addition of Ca[2+] and Mg[2+] (0-3.5 mmol/L, CIP: 1.25 μmol/L), the transport rates were reduced to 52.4% and 63.0%, respectively. Computational chemistry analysis further demonstrated a deprotonated carboxyl in the tryptophan residues of biofilms acted as a major bridge site, of which one side is a metal and the other is a metal girder jointly connected to the carboxyl and carbonyl of a FQA. The bacterial growth rate depends on the bridging energy at anchoring site, which underlines the environmental importance of metal bridge formed in biofilm matrices in bacterially antibiotic resistance.}, } @article {pmid27637885, year = {2016}, author = {Nandi, M and Berry, C and Brassinga, AK and Belmonte, MF and Fernando, WG and Loewen, PC and de Kievit, TR}, title = {Pseudomonas brassicacearum strain DF41 kills Caenorhabditis elegans through biofilm-dependent and biofilm-independent mechanisms.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {23}, pages = {6889-6898}, pmid = {27637885}, issn = {1098-5336}, support = {P40 OD010440/OD/NIH HHS/United States ; }, abstract = {UNLABELLED: Pseudomonas brassicacearum DF41 is a biocontrol agent that suppresses disease caused by the fungal pathogen Sclerotinia sclerotiorum A number of exometabolites are produced by DF41 including the lipopeptide sclerosin, hydrogen cyanide (HCN) and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional level by quorum sensing (QS) and the Gac-two component regulatory system. In order to be successful, a biocontrol agent must persist in the environment at levels sufficient for pathogen control. Bacterivorous predators, including nematodes, represent a challenge to the establishment of introduced microorganisms. In the current study, DF41 was investigated for its ability to resist predation by Caenorhabditis elegans. We discovered that this bacterium is capable of killing C. elegans through two different mechanisms: the first involves exposure to toxic metabolites; and the second entails biofilm formation on the nematode head blocking the buccal cavity. Biofilm formation on nematodes, which has only been reported for Yersinia spp. and Xenorhabdus nematophila, is dependent upon the Gac system. Biofilms were not observed when bacteria were grown on NaCl-containing media, and on C. elegans biofilm-resistant mutants. Co-culturing with nematodes lead to increased expression of the pdfRI-rfiA QS genes and hcnA which is under QS control. HCN was the most nematicidal of the exometabolites, suggesting that this bacterium can respond to predator cues and upregulate expression of toxins accordingly. In summary, DF41 is able to respond to the presence of C. elegans and through two distinct mechanisms it can escape predation.

IMPORTANCE: Pseudomonas brassicacearum DF41 can suppress fungal pathogens through a process known as biocontrol. To be successful, a biocontrol agent must be able to persist in the environment at levels sufficient for pathogen control. Predators including the nematode Caenorhabditis elegans represent a threat to persistence. The aim of the current study was to investigate the DF41-C. elegans interaction. We discovered that DF41 is able to escape predation through two distinct mechanisms. The first involves exposure to toxic bacterial metabolites and the second entails formation of a sticky coating on the nematode head, called a biofilm, which blocks feeding and causes starvation. This is the first report of a pseudomonad forming biofilms on the C. elegans surface. When grown with C. elegans, DF41 exhibits altered gene expression and metabolite production indicating that this bacterium can sense the presence of these predators and adjust its physiology accordingly.}, } @article {pmid27636892, year = {2016}, author = {Jiménez-Fernández, A and López-Sánchez, A and Jiménez-Díaz, L and Navarrete, B and Calero, P and Platero, AI and Govantes, F}, title = {Complex Interplay between FleQ, Cyclic Diguanylate and Multiple σ Factors Coordinately Regulates Flagellar Motility and Biofilm Development in Pseudomonas putida.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0163142}, pmid = {27636892}, issn = {1932-6203}, mesh = {Bacterial Proteins/*metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Promoter Regions, Genetic ; Pseudomonas aeruginosa/growth & development/*metabolism ; Sigma Factor/*metabolism ; Trans-Activators/*metabolism ; }, abstract = {Most bacteria alternate between a free living planktonic lifestyle and the formation of structured surface-associated communities named biofilms. The transition between these two lifestyles requires a precise and timely regulation of the factors involved in each of the stages that has been likened to a developmental process. Here we characterize the involvement of the transcriptional regulator FleQ and the second messenger cyclic diguanylate in the coordinate regulation of multiple functions related to motility and surface colonization in Pseudomonas putida. Disruption of fleQ caused strong defects in flagellar motility, biofilm formation and surface attachment, and the ability of this mutation to suppress multiple biofilm-related phenotypes associated to cyclic diguanylate overproduction suggests that FleQ mediates cyclic diguanylate signaling critical to biofilm growth. We have constructed a library containing 94 promoters potentially involved in motility and biofilm development fused to gfp and lacZ, screened this library for FleQ and cyclic diguanylate regulation, and assessed the involvement of alternative σ factors σN and FliA in the transcription of FleQ-regulated promoters. Our results suggest a dual mode of action for FleQ. Low cyclic diguanylate levels favor FleQ interaction with σN-dependent promoters to activate the flagellar cascade, encompassing the flagellar cluster and additional genes involved in cyclic diguanylate metabolism, signal transduction and gene regulation. On the other hand, characterization of the FleQ-regulated σN- and FliA-independent PlapA and PbcsD promoters revealed two disparate regulatory mechanisms leading to a similar outcome: the synthesis of biofilm matrix components in response to increased cyclic diguanylate levels.}, } @article {pmid27635214, year = {2016}, author = {Mohsenipour, Z and Hassanshahian, M}, title = {Antibacterial Activity of Euphorbia hebecarpa Alcoholic Extracts Against Six Human Pathogenic Bacteria in Planktonic and Biofilm Forms.}, journal = {Jundishapur journal of microbiology}, volume = {9}, number = {6}, pages = {e34701}, pmid = {27635214}, issn = {2008-3645}, abstract = {BACKGROUND: Biofilm formation is a primary cause of considerable bacterial destruction.

OBJECTIVES: In an effort to combat these industrial and medical bacterial biofilm problems, our study aims to determine the antimicrobial effect of Euphorbia hebecarpa.

MATERIALS AND METHODS: The inhibition efficiency of alcoholic extracts on the planktonic form of six pathogenic bacteria was evaluated using a disk diffusion technique. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were determined by means of a macrobroth dilution method. The effects of the extracts on biofilms were calculated using a microtiter plate method.

RESULTS: The results of the disk diffusion assay (MBC and MIC) confirmed that E. hebecarpa ethanolic extracts were more efficient than methanolic extracts in the inhibition of planktonic forms of bacteria. Also, the inhibitory effect of the extracts in a broth medium was greater than in a solid medium. Extracts of E. hebecarpa were found to inhibit biofilm formation better than demolish of biofilm and preventing metabolic activity of bacteria in biofilm structures. The greatest inhibitory effects of E. hebecarpa extracts were observed for the biofilm formation of B. cereus (92.81%). In addition, the greatest demolition was observed for the S. aureus biofilm (74.49%), and the metabolic activity decrement of this bacteria was highest (78.21%) of all the tested bacteria.

CONCLUSIONS: The results of this study suggest that E. hebecarpa extracts can be used to inhibit the planktonic and biofilm forms of these selected bacteria.}, } @article {pmid27630827, year = {2016}, author = {Bachert, BA and Choi, SJ and LaSala, PR and Harper, TI and McNitt, DH and Boehm, DT and Caswell, CC and Ciborowski, P and Keene, DR and Flores, AR and Musser, JM and Squeglia, F and Marasco, D and Berisio, R and Lukomski, S}, title = {Unique Footprint in the scl1.3 Locus Affects Adhesion and Biofilm Formation of the Invasive M3-Type Group A Streptococcus.}, journal = {Frontiers in cellular and infection microbiology}, volume = {6}, number = {}, pages = {90}, pmid = {27630827}, issn = {2235-2988}, support = {P20 RR016440/RR/NCRR NIH HHS/United States ; R01 AI050666/AI/NIAID NIH HHS/United States ; R21 AI083683/AI/NIAID NIH HHS/United States ; P30 GM103509/GM/NIGMS NIH HHS/United States ; S10 RR020866/RR/NCRR NIH HHS/United States ; P20 GM103434/GM/NIGMS NIH HHS/United States ; P30 GM103488/GM/NIGMS NIH HHS/United States ; S10 OD016165/OD/NIH HHS/United States ; }, mesh = {Animals ; Antigens, Bacterial/genetics ; *Bacterial Adhesion ; Bacterial Outer Membrane Proteins/genetics ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Carrier Proteins/genetics ; Collagen/*genetics/metabolism ; Disease Models, Animal ; Genetic Complementation Test ; *Genetic Loci ; Humans ; Mice ; Serogroup ; Streptococcal Infections/microbiology/pathology ; Streptococcus pyogenes/classification/*genetics/*physiology ; }, abstract = {The streptococcal collagen-like proteins 1 and 2 (Scl1 and Scl2) are major surface adhesins that are ubiquitous among group A Streptococcus (GAS). Invasive M3-type strains, however, have evolved two unique conserved features in the scl1 locus: (i) an IS1548 element insertion in the scl1 promoter region and (ii) a nonsense mutation within the scl1 coding sequence. The scl1 transcript is drastically reduced in M3-type GAS, contrasting with a high transcription level of scl1 allele in invasive M1-type GAS. This leads to a lack of Scl1 expression in M3 strains. In contrast, while scl2 transcription and Scl2 production are elevated in M3 strains, M1 GAS lack Scl2 surface expression. M3-type strains were shown to have reduced biofilm formation on inanimate surfaces coated with cellular fibronectin and laminin, and in human skin equivalents. Repair of the nonsense mutation and restoration of Scl1 expression on M3-GAS cells, restores biofilm formation on cellular fibronectin and laminin coatings. Inactivation of scl1 in biofilm-capable M28 and M41 strains results in larger skin lesions in a mouse model, indicating that lack of Scl1 adhesin promotes bacterial spread over localized infection. These studies suggest the uniquely evolved scl1 locus in the M3-type strains, which prevents surface expression of the major Scl1 adhesin, contributed to the emergence of the invasive M3-type strains. Furthermore these studies provide insight into the molecular mechanisms mediating colonization, biofilm formation, and pathogenesis of group A streptococci.}, } @article {pmid27630633, year = {2016}, author = {Nale, JY and Chutia, M and Carr, P and Hickenbotham, PT and Clokie, MR}, title = {'Get in Early'; Biofilm and Wax Moth (Galleria mellonella) Models Reveal New Insights into the Therapeutic Potential of Clostridium difficile Bacteriophages.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1383}, pmid = {27630633}, issn = {1664-302X}, abstract = {Clostridium difficile infection (CDI) is a global health threat associated with high rates of morbidity and mortality. Conventional antibiotic CDI therapy can result in treatment failure and recurrent infection. C. difficile produces biofilms which contribute to its virulence and impair antimicrobial activity. Some bacteriophages (phages) can penetrate biofilms and thus could be developed to either replace or supplement antibiotics. Here, we determined the impact of a previously optimized 4-phage cocktail on C. difficile ribotype 014/020 biofilms, and additionally as adjunct to vancomycin treatment in Galleria mellonella larva CDI model. The phages were applied before or after biofilm establishment in vitro, and the impact was analyzed according to turbidity, viability counts and topography as observed using scanning electron and confocal microscopy. The infectivity profiles and efficacies of orally administered phages and/or vancomycin were ascertained by monitoring colonization levels and larval survival rates. Phages prevented biofilm formation, and penetrated established biofilms. A single phage application reduced colonization causing extended longevity in the remedial treatment and prevented disease in the prophylaxis group. Multiple phage doses significantly improved the larval remedial regimen, and this treatment is comparable to vancomycin and the combined treatments. Taken together, our data suggest that the phages significantly reduce C. difficile biofilms, and prevent colonization in the G. mellonella model when used alone or in combination with vancomycin. The phages appear to be highly promising therapeutics in the targeted eradication of CDI and the use of these models has revealed that prophylactic use could be a propitious therapeutic option.}, } @article {pmid27630624, year = {2016}, author = {Liu, W and Røder, HL and Madsen, JS and Bjarnsholt, T and Sørensen, SJ and Burmølle, M}, title = {Interspecific Bacterial Interactions are Reflected in Multispecies Biofilm Spatial Organization.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1366}, pmid = {27630624}, issn = {1664-302X}, abstract = {Interspecies interactions are essential for the persistence and development of any kind of complex community, and microbial biofilms are no exception. Multispecies biofilms are structured and spatially defined communities that have received much attention due to their omnipresence in natural environments. Species residing in these complex bacterial communities usually interact both intra- and interspecifically. Such interactions are considered to not only be fundamental in shaping overall biomass and the spatial distribution of cells residing in multispecies biofilms, but also to result in coordinated regulation of gene expression in the different species present. These communal interactions often lead to emergent properties in biofilms, such as enhanced tolerance against antibiotics, host immune responses, and other stresses, which have been shown to provide benefits to all biofilm members not only the enabling sub-populations. However, the specific molecular mechanisms of cellular processes affecting spatial organization, and vice versa, are poorly understood and very complex to unravel. Therefore, detailed description of the spatial organization of individual bacterial cells in multispecies communities can be an alternative strategy to reveal the nature of interspecies interactions of constituent species. Closing the gap between visual observation and biological processes may become crucial for resolving biofilm related problems, which is of utmost importance to environmental, industrial, and clinical implications. This review briefly presents the state of the art of studying interspecies interactions and spatial organization of multispecies communities, aiming to support theoretical and practical arguments for further advancement of this field.}, } @article {pmid27626916, year = {2016}, author = {Ovnat Tamir, S and Marom, T and Zaks, B and Steinberg, D}, title = {Pseudomonal Biofilm Topographic Distribution on Tympanostomy Tubes: An In Vitro Model.}, journal = {The Pediatric infectious disease journal}, volume = {35}, number = {12}, pages = {1357-1360}, doi = {10.1097/INF.0000000000001331}, pmid = {27626916}, issn = {1532-0987}, mesh = {Bacterial Adhesion ; *Biofilms ; Humans ; Middle Ear Ventilation/*instrumentation ; *Models, Biological ; Otitis Media/microbiology ; Prostheses and Implants/*microbiology ; *Pseudomonas aeruginosa ; }, abstract = {In vitro growth of Pseudomonas aeruginosa biofilm on tympanostomy tubes showed that in Armstrong T-tubes, biofilm colonies were mainly located in the perpendicular junction between the body and the flanges, but in Paparella-type tube, they concentrated on the round rims. These "weakness" zones can be the future target areas for geometry changes, and can be specifically coated with antibiofilm materials.}, } @article {pmid27624133, year = {2016}, author = {Winter, MB and Salcedo, EC and Lohse, MB and Hartooni, N and Gulati, M and Sanchez, H and Takagi, J and Hube, B and Andes, DR and Johnson, AD and Craik, CS and Nobile, CJ}, title = {Global Identification of Biofilm-Specific Proteolysis in Candida albicans.}, journal = {mBio}, volume = {7}, number = {5}, pages = {}, pmid = {27624133}, issn = {2150-7511}, support = {R01 GM104659/GM/NIGMS NIH HHS/United States ; R00 AI100896/AI/NIAID NIH HHS/United States ; F32 CA168150/CA/NCI NIH HHS/United States ; T32 ES007020/ES/NIEHS NIH HHS/United States ; R01 AI083311/AI/NIAID NIH HHS/United States ; T32 GM064337/GM/NIGMS NIH HHS/United States ; R25 GM056847/GM/NIGMS NIH HHS/United States ; R01 AI073289/AI/NIAID NIH HHS/United States ; P41 GM103481/GM/NIGMS NIH HHS/United States ; T32 AI060537/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Aspartic Acid Endopeptidases/*metabolism ; Biofilms/*growth & development ; Candida albicans/*metabolism/*physiology ; Candidiasis/microbiology ; Catheter-Related Infections/microbiology ; Disease Models, Animal ; Fungal Proteins/*metabolism ; *Proteolysis ; Proteome/analysis ; Rats ; }, abstract = {UNLABELLED: Candida albicans is a fungal species that is part of the normal human microbiota and also an opportunistic pathogen capable of causing mucosal and systemic infections. C. albicans cells proliferate in a planktonic (suspension) state, but they also form biofilms, organized and tightly packed communities of cells attached to a solid surface. Biofilms colonize many niches of the human body and persist on implanted medical devices, where they are a major source of new C. albicans infections. Here, we used an unbiased and global substrate-profiling approach to discover proteolytic activities produced specifically by C. albicans biofilms, compared to planktonic cells, with the goal of identifying potential biofilm-specific diagnostic markers and targets for therapeutic intervention. This activity-based profiling approach, coupled with proteomics, identified Sap5 (Candidapepsin-5) and Sap6 (Candidapepsin-6) as major biofilm-specific proteases secreted by C. albicans Fluorogenic peptide substrates with selectivity for Sap5 or Sap6 confirmed that their activities are highly upregulated in C. albicans biofilms; we also show that these activities are upregulated in other Candida clade pathogens. Deletion of the SAP5 and SAP6 genes in C. albicans compromised biofilm development in vitro in standard biofilm assays and in vivo in a rat central venous catheter biofilm model. This work establishes secreted proteolysis as a promising enzymatic marker and potential therapeutic target for Candida biofilm formation.

IMPORTANCE: Biofilm formation by the opportunistic fungal pathogen C. albicans is a major cause of life-threatening infections. This work provides a global characterization of secreted proteolytic activity produced specifically by C. albicans biofilms. We identify activity from the proteases Sap5 and Sap6 as highly upregulated during C. albicans biofilm formation and develop Sap-cleavable fluorogenic substrates that enable the detection of biofilms from C. albicans and also from additional pathogenic Candida species. Furthermore, SAP5 and SAP6 deletions confirm that both proteases are required for proper biofilm development in vitro and in vivo We propose that secreted proteolysis is a promising marker for the diagnosis and potential therapeutic targeting of Candida biofilm-associated infections.}, } @article {pmid27623781, year = {2016}, author = {Teh, AH and Lee, SM and Dykes, GA}, title = {The Influence of Prior Modes of Growth, Temperature, Medium, and Substrate Surface on Biofilm Formation by Antibiotic-Resistant Campylobacter jejuni.}, journal = {Current microbiology}, volume = {73}, number = {6}, pages = {859-866}, pmid = {27623781}, issn = {1432-0991}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion ; *Biofilms/drug effects ; Campylobacter jejuni/*drug effects/genetics/growth & development/*physiology ; Culture Media/chemistry/*metabolism ; Drug Resistance, Bacterial ; Temperature ; }, abstract = {Campylobacter jejuni is one of the most common causes of bacterial gastrointestinal food-borne infection worldwide. It has been suggested that biofilm formation may play a role in survival of these bacteria in the environment. In this study, the influence of prior modes of growth (planktonic or sessile), temperatures (37 and 42 °C), and nutrient conditions (nutrient broth and Mueller-Hinton broth) on biofilm formation by eight C. jejuni strains with different antibiotic resistance profiles was examined. The ability of these strains to form biofilm on different abiotic surfaces (stainless steel, glass, and polystyrene) as well as factors potentially associated with biofilm formation (bacterial surface hydrophobicity, auto-aggregation, and initial attachment) was also determined. The results showed that cells grown as sessile culture generally have a greater ability to form biofilm (P < 0.05) compared to their planktonic counterparts. Biofilm was also greater (P < 0.05) in lower nutrient media, while growth at different temperatures affects biofilm formation in a strain-dependent manner. The strains were able to attach and form biofilms on different abiotic surfaces, but none of them demonstrated strong, complex, or structured biofilm formation. There were no clear trends between the bacterial surface hydrophobicity, auto-aggregation, attachment, and biofilm formation by the strains. This finding suggests that environmental factors did affect biofilm formation by C. jejuni, and they are more likely to persist in the environment in the form of mixed-species rather than monospecies biofilms.}, } @article {pmid27623312, year = {2015}, author = {Maher, MC and Lim, JY and Gunawan, C and Cegelski, L}, title = {Cell-Based High-Throughput Screening Identifies Rifapentine as an Inhibitor of Amyloid and Biofilm Formation in Escherichia coli.}, journal = {ACS infectious diseases}, volume = {1}, number = {10}, pages = {460-468}, doi = {10.1021/acsinfecdis.5b00055}, pmid = {27623312}, issn = {2373-8227}, abstract = {Escherichia coli assemble functional amyloid fibers termed curli that contribute to bacterial adhesion, biofilm formation, and host pathogenesis. We developed a cell-based high-throughput screen to identify inhibitors of curli-mediated adhesion in the laboratory strain MC4100 and curli-associated biofilm formation in the uropathogenic E. coli clinical isolate UTI89. Inhibitors of biofilm formation can operate through many mechanisms, and such inhibitors could hold therapeutic value in preventing and treating urinary tract infections. The curli-specific screen allows the identification of compounds that inhibit either curli expression, curli biogenesis, or adhesion by normally produced curli. In screening the NIH Clinical Collection of 446 compounds, we identified rifapentine as a potent inhibitor in both of these screens. Rifapentine is an antibiotic used to treat tuberculosis that targets RNA polymerase, but prevents curli-dependent adhesion and biofilm formation in E. coli at concentrations below those that affect viability. Rifapentine inhibits curli production and prevents biofilm formation on plastic, on agar, and at the air-liquid interface by inhibiting curli gene transcription. Comparisons with a cephalosporin antibiotic further revealed that curli production is not affected by standard antibiotic treatment and cell killing pressure. Thus, we reveal a new role independent of killing activity for rifapentine as an inhibitor of curli and curli-mediated biofilm formation.}, } @article {pmid27623227, year = {2016}, author = {Bhattacharjee, A and Nusca, TD and Hochbaum, AI}, title = {Rhamnolipids Mediate an Interspecies Biofilm Dispersal Signaling Pathway.}, journal = {ACS chemical biology}, volume = {11}, number = {11}, pages = {3068-3076}, doi = {10.1021/acschembio.6b00750}, pmid = {27623227}, issn = {1554-8937}, support = {P30 CA062203/CA/NCI NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Escherichia coli/*drug effects/metabolism ; Glycolipids/*pharmacology ; Pseudomonas aeruginosa/*drug effects/metabolism ; Quorum Sensing ; Signal Transduction/*drug effects ; Species Specificity ; }, abstract = {Bacterial biofilms are problematic in natural and anthropogenic environments, and they confer protective properties on their constituent cells, making them difficult to treat with conventional antibiotics. Antibiofilm strategies, therefore, represent a promising direction of research for treating biofilm infections. Natural autodispersal and interspecies dispersal signaling pathways provide insight into cell-cell communication mechanisms, species dynamics in mixed communities, and potential targets for infection therapies. Here, we describe a novel interspecies dispersal signaling pathway between Pseudomonas aeruginosa and Escherichia coli. E. coli biofilms disperse in response to compounds in P. aeruginosa culture supernatant. Two components of the P. aeruginosa Las and Rhl quorum sensing systems, N-(3-oxo-dodecanoyl) homoserine lactone (3oxoC12HSL) and rhamnolipids, are found to act cooperatively to disperse E. coli biofilms. Our results indicate that rhamnolipids do not affect growth, biofilm development, or dispersal in E. coli but instead complement 3oxoC12HSL signaling by inducing selective permeability of the E. coli membrane. The increased target cell permeability is consistent with rhamnolipid-mediated removal of lipopolysaccharide from E. coli membranes and appears to selectively increase the permeability of lipophilic acyl homoserine lactones. This work suggests that rhamnolipids play a critical role in P. aeruginosa-E. coli interspecies signaling. Rhamnolipids and other biosurfactants may have similar effects in other intra- and interspecies chemical signaling pathways.}, } @article {pmid27622249, year = {2016}, author = {Selasi, GN and Nicholas, A and Jeon, H and Na, SH and Kwon, HI and Kim, YJ and Heo, ST and Oh, MH and Lee, JC}, title = {Differences in Biofilm Mass, Expression of Biofilm-Associated Genes, and Resistance to Desiccation between Epidemic and Sporadic Clones of Carbapenem-Resistant Acinetobacter baumannii Sequence Type 191.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0162576}, pmid = {27622249}, issn = {1932-6203}, mesh = {Acinetobacter Infections/drug therapy/*epidemiology/*microbiology ; Acinetobacter baumannii/*drug effects/*genetics/physiology ; Biofilms/drug effects/growth & development ; Carbapenems/*pharmacology ; Cross Infection/drug therapy/*epidemiology/*microbiology ; Desiccation ; Epidemics ; Genes, Bacterial ; Humans ; Republic of Korea/epidemiology ; beta-Lactam Resistance/*genetics ; }, abstract = {Understanding the biology behind the epidemicity and persistence of Acinetobacter baumannii in the hospital environment is critical to control outbreaks of infection. This study investigated the contributing factors to the epidemicity of carbapenem-resistant A. baumannii (CRAB) sequence type (ST) 191 by comparing the differences in biofilm formation, expression of biofilm-associated genes, and resistance to desiccation between major epidemic (n = 16), minor epidemic (n = 12), and sporadic (n = 12) clones. Biofilm mass was significantly greater in the major epidemic than the minor epidemic and sporadic clones. Major and minor epidemic clones expressed biofilm-associated genes, abaI, bap, pgaABCD, and csuA/BABCDE, higher than the sporadic clones in sessile conditions. The csuC, csuD, and csuE genes were more highly expressed in the major epidemic than minor epidemic clones. Interestingly, minor epidemic clones expressed more biofilm-associated genes than the major epidemic clone under planktonic conditions. Major epidemic clones were more resistant to desiccation than minor epidemic and sporadic clones on day 21. In conclusion, the epidemic CRAB ST191 clones exhibit a higher capacity to form biofilms, express the biofilm-associated genes under sessile conditions, and resist desiccation than sporadic clones. These phenotypic and genotypic characteristics of CRAB ST191 may account for the epidemicity of specific CRAB ST191 clones in the hospital.}, } @article {pmid27620654, year = {2017}, author = {Levine, M and Lohinai, Z and Teles, RP}, title = {Low Biofilm Lysine Content in Refractory Chronic Periodontitis.}, journal = {Journal of periodontology}, volume = {88}, number = {2}, pages = {181-189}, doi = {10.1902/jop.2016.160302}, pmid = {27620654}, issn = {1943-3670}, mesh = {Adult ; Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Cadaverine/analysis ; Chromatography, Liquid ; Chronic Periodontitis/microbiology/*therapy ; Combined Modality Therapy ; Dental Scaling ; Female ; Humans ; Lysine/*analysis ; Male ; Middle Aged ; Root Planing ; Smoking/adverse effects ; }, abstract = {BACKGROUND: Chronic periodontitis is controlled without antibiotics by scaling and root planing (SRP) to remove dental biofilm. It has been previously reported that the epithelial barrier to bacterial proinflammatory products is impaired when biofilm lysine falls below the minimal content of normal blood plasma. Aims were to examine whether being refractory and requiring antibiotics to supplement SRP were associated with low biofilm lysine contents.

METHODS: Sixteen patients with periodontitis and six periodontally healthy volunteers (HVs) (respective mean ages: 57 ± 6 and 36 ± 8 years) were examined. Patients with periodontitis received SRP and surgery, and HVs received prophylaxis. At quarterly maintenance or prophylaxis visits during the subsequent year, therapeutic response was good (GR, n = 9) or poor (PR, n = 7; including five cigarette smokers). Biofilm cadaverine, lysine, and other amino acid (AA) contents were determined by liquid chromatography. Cadaverine mole fraction of lysine plus cadaverine (CF) indicated biofilm lysine decarboxylase activity.

RESULTS: Biofilm lysine was 0.19 ± 0.10 and 0.20 ± 0.09 μmol/mg in GRs and HVs, but 0.07 ± 0.03 μmol/mg in PRs (Kruskal-Wallis: P <0.01). All AAs were depleted in biofilm from smokers, but only lysine was depleted in biofilm from non-smokers. CF was inversely associated with clinical attachment level (CAL) at baseline before therapy in all patients (R[2] = 0.28, P <0.01) and with CAL change after therapy in GR (R[2] = 0.49, P <0.05). Lysine and cadaverine contents discriminated PRs from GRs and HVs (Wilks' λ = 0.499, P <0.012).

CONCLUSIONS: Refractory responses requiring antibiotic therapy result from smoking and/or microbial infections that starve the biofilm and epithelial attachment of lysine. Biofilm CF is associated with periodontitis severity pretherapy and extent of therapeutic response post-therapy.}, } @article {pmid27619684, year = {2016}, author = {Braun, M}, title = {Questions concerning "Polymicrobial Gardnerella biofilm resists repeated intravaginal antiseptic treatment in a subset of women with bacterial vaginosis: a preliminary report".}, journal = {Archives of gynecology and obstetrics}, volume = {294}, number = {5}, pages = {1105-1106}, doi = {10.1007/s00404-016-4203-x}, pmid = {27619684}, issn = {1432-0711}, mesh = {Anti-Infective Agents, Local ; Biofilms ; Female ; *Gardnerella ; Gardnerella vaginalis ; Humans ; Vagina ; *Vaginosis, Bacterial ; }, } @article {pmid27615430, year = {2016}, author = {An, D and Wang, X and Li, J and Jiang, S and Ma, X and Zhang, H and Shi, H and Sun, H and Ye, L and Li, J}, title = {The Activity of Fungichromin against the Formation of Candida albicans Biofilm.}, journal = {Biological & pharmaceutical bulletin}, volume = {39}, number = {12}, pages = {1948-1954}, doi = {10.1248/bpb.b16-00380}, pmid = {27615430}, issn = {1347-5215}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/genetics/physiology/ultrastructure ; Gene Expression Regulation/drug effects ; Genes, Fungal ; Macrolides/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Polyenes/pharmacology ; }, abstract = {The effect of fungichromin (FC) on the formation of Candida albicans biofilm was assessed using 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction method, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results showed that FC revealed an inhibitory effect on the formation of C. albicans biofilm in a dose-dependent manner with a minimum inhibitory concentration (MIC) of 10 µg/mL. Over 80% of biofilm formation was inhibited by FC at the concentration of 40 µg/mL when compared with the control. Similarly, real-time PCR showed that the expression of the genes such as ALS1, ALS3, HWP1, EFG1, HYR1, CPH1 and BCR1 appeared to be remarkably affected by FC at the concentration of 20 µg/mL during the biofilm formation. In addition, FC could also induce the apoptosis of C. albicans cells in a dose-dependent manner. Therefore, FC displayed potent activity against the formation of C. albicans biofilm in vitro and played an important role in reducing the incidence of device-associated infections.}, } @article {pmid27614861, year = {2017}, author = {Castro, JS and Calijuri, ML and Assemany, PP and Cecon, PR and de Assis, IR and Ribeiro, VJ}, title = {Microalgae biofilm in soil: Greenhouse gas emissions, ammonia volatilization and plant growth.}, journal = {The Science of the total environment}, volume = {574}, number = {}, pages = {1640-1648}, doi = {10.1016/j.scitotenv.2016.08.205}, pmid = {27614861}, issn = {1879-1026}, mesh = {Ammonia/*analysis ; *Biofilms ; Carbon Dioxide/analysis ; Chlorella vulgaris ; Fertilizers ; *Greenhouse Gases ; Methane/analysis ; *Microalgae ; Nitrous Oxide/analysis ; Pennisetum/*growth & development ; *Soil ; Volatilization ; }, abstract = {Microalgal biofilm in soils represents an alternative fertilization method for agricultural sustainability. In the present study, greenhouse gas emission, soil ammonia volatilization, and the growth of Pennisetum glaucum were evaluated under the effect of a microalgal biofilm, commercial urea, and a control (without application of a nitrogen source). CH4 emissions were equal for the three treatments (p>0.05). CO2 emissions significantly increased in microalgal biofilm treatment (p<0.01), which was also responsible for the highest N2O emissions (p<0.01). The ammonia (NNH3) volatilization losses were 4.63%, 18.98%, and 0.82% for the microalgal biofilm, urea, and control treatments, respectively. The main differences in soil characteristics were an increase in nitrogen and an increase in cation exchange capacity (p<0.01) caused by the algal biomass application to the soil. The soil organic matter content significantly differed (p<0.05) among the three treatments, with the microalgal biofilm treatment having the greatest increase in soil organic matter. Significant differences were observed for shoot dry matter mass and nitrogen content in the plants from both treatments where nitrogen sources were applied. All treatments differed from each other in leaf dry matter mass, with the urea treatment increasing the most. Chlorella vulgaris was the dominant microalgal specie in the soil.}, } @article {pmid27614580, year = {2016}, author = {Revilla, M and Galán, B and Viguri, JR}, title = {Analysis and modelling of predation on biofilm activated sludge process: Influence on microbial distribution, sludge production and nutrient dosage.}, journal = {Bioresource technology}, volume = {220}, number = {}, pages = {572-583}, doi = {10.1016/j.biortech.2016.08.107}, pmid = {27614580}, issn = {1873-2976}, mesh = {Bacteria/*metabolism ; *Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; Bioreactors/microbiology ; Computer Simulation ; *Models, Theoretical ; Nitrogen/*analysis ; Phosphorus/*analysis ; Sewage/*microbiology ; Solubility ; Time Factors ; Waste Disposal, Fluid ; }, abstract = {The influence of predation on the biofilm activated sludge (BAS) process is studied using a unified model that incorporates hydrolysis and predation phenomena into the two stages of the BAS system: moving bed biofilm reactor pre-treatment (bacterial-predator stage) and activated sludge (predator stage). The unified model adequately describes the experimental results obtained in a cellulose and viscose full-scale wastewater plant and has been used to evaluate the role and contribution of predator microorganisms towards removal of COD, nutrient requirements, sludge production and microbial distribution. The results indicate that predation is the main factor responsible for the reduction of both nutrient requirements and sludge production. Furthermore, increasing the sludge retention time (SRT) does not influence the total biomass content in the AS reactor of a BAS process in two different industrial wastewater treatments.}, } @article {pmid27614460, year = {2017}, author = {Fariña, N and Samudio, M and Carpinelli, L and Nentwich, MM and de Kaspar, HM}, title = {Methicillin resistance and biofilm production of Staphylococcus epidermidis isolates from infectious and normal flora conjunctiva.}, journal = {International ophthalmology}, volume = {37}, number = {4}, pages = {819-825}, pmid = {27614460}, issn = {1573-2630}, mesh = {Anti-Bacterial Agents/therapeutic use ; Biofilms/*growth & development ; Conjunctiva/*microbiology ; Conjunctivitis/drug therapy/*microbiology ; DNA, Bacterial/analysis ; Eye Infections, Bacterial/drug therapy/*microbiology ; Humans ; Methicillin/therapeutic use ; *Methicillin Resistance ; Polymerase Chain Reaction ; Retrospective Studies ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus epidermidis/drug effects/*physiology ; }, abstract = {PURPOSE: Coagulase-negative staphylococci have been reported to be the most frequent cause of bacterial postoperative endophthalmitis. Biofilm formation is the major virulence factor of Staphylococcus epidermidis and is often associated with methicillin resistance. This study aims at evaluating the presence of biofilm-producing and methicillin resistance genes (mecA) in S. epidermidis.

METHODS: S. epidermidis isolated from clinically infected sites (group 1) and from normal human conjunctiva (group 2) were studied. All the isolates were tested for their ability to produce biofilm by the conventional Christensen´s method and the presence of mecA by PCR using the 22-mer oligonucleotides as primers.

RESULTS: In total 20 isolates from group 1 and 22 from group 2 were studied. Biofilm and mecA were detected in 15 (75 %) and in 14 (70 %) in group 1 as compared to 8 (36.3 %) and 4 (18.2 %) in group 2 (p = 0.016). Simultaneously, biofilm production and presence of mecA genes were observed in 13/20 (65.0 %) in group 1, and 4/22 (18.2 %) in group 2 (p = 0.002). Multi-resistance was observed in 55 % in group 1 and 9 % in group 2 (p = 0.002); 57 % of the biofilm-producing strains was multi-resistant in contrast to none of the non-producing strains. In all multi-resistant strains, biofilm production was seen.

CONCLUSIONS: Biofilm formation capacity was widely distributed, particularly among mecA (+) S. epidermidis strains, which also displayed a high diversity of antibiotic resistance profiles.}, } @article {pmid27614242, year = {2016}, author = {de Souza, IO and Schrekker, CM and Lopes, W and Orru, RV and Hranjec, M and Perin, N and Machado, M and Oliveira, LF and Donato, RK and Stefani, V and Fuentefria, AM and Schrekker, HS}, title = {Bifunctional fluorescent benzimidazo[1,2-α]quinolines for Candida spp. biofilm detection and biocidal activity.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {163}, number = {}, pages = {319-326}, doi = {10.1016/j.jphotobiol.2016.08.037}, pmid = {27614242}, issn = {1873-2682}, mesh = {Antifungal Agents/chemistry/pharmacology ; *Biofilms/drug effects ; Candida albicans/*drug effects/isolation & purification/*physiology ; Drug Resistance, Fungal/drug effects ; Fluorescent Dyes/*chemistry/*pharmacology ; Microbial Sensitivity Tests ; Quinolines/*chemistry/*pharmacology ; }, abstract = {Biofilms provide an ideal environment for protecting the microbial cells from damage caused by humoral and cellular immune system components, promoting resistance, infections and increasing mortality and morbidity of patients in health facilities. In an attempt to provide an innovative solution for preventing contamination in hospital environments, this study evaluated nine structural complementary fluorescent benzimidazo[1,2-α]quinolines as bifunctional agents that both detect and have biocidal activity against yeast biofilms on stainless steel surfaces. The benzimidazoles' staining capability was determined by a fluorescence microscopy study and spraying the substance on yeast biofilm contaminated stainless steel surfaces. Furthermore, their in vitro human leukocyte cytotoxicity was evaluated with trypan blue and their biocidal activity was determined as the minimum inhibitory concentration against Candida tropicalis, C. albicans and C. parapsilosis strains. Moreover, scanning electron micrographs were recorded to study the biocidal activity. This resulted in the identification of 7, which presents all the desired characteristics (such as solubility) and capabilities (staining and biocide activity against all tested biofilm forming yeast strains) at the same time. As such, benzimidazole 7 has the potential to guarantee the use of disinfected medical and surgical instruments in clinical and surgical procedures, consequently, contributing to an increased safety for patients.}, } @article {pmid27612768, year = {2016}, author = {Sun, D and Xu, D and Yang, C and Chen, J and Shahzad, MB and Sun, Z and Zhao, J and Gu, T and Yang, K and Wang, G}, title = {Inhibition of Staphylococcus aureus biofilm by a copper-bearing 317L-Cu stainless steel and its corrosion resistance.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {69}, number = {}, pages = {744-750}, doi = {10.1016/j.msec.2016.07.050}, pmid = {27612768}, issn = {1873-0191}, mesh = {Animals ; Biofilms/*drug effects ; Cell Death/drug effects ; Copper/*pharmacology ; Corrosion ; Embryo, Nonmammalian/drug effects ; Microbial Sensitivity Tests ; Photoelectron Spectroscopy ; Polysaccharides, Bacterial/pharmacology ; Spectrometry, X-Ray Emission ; Spectroscopy, Fourier Transform Infrared ; Stainless Steel/*pharmacology/toxicity ; Staphylococcus aureus/*drug effects ; Surface Properties ; Toxicity Tests ; Zebrafish/embryology ; }, abstract = {The present study investigated the antibacterial performance, corrosion resistance and surface properties of antibacterial austenitic 317L-Cu stainless steel (317L-Cu SS). After 4.5wt% copper was added to 317L stainless steel (317L SS), the new alloy underwent solid solution and aging heat treatment. Fluorescent staining using 4',6-diamidino-2-phenylindole (DAPI) revealed that the 317L-Cu SS showed strong antibacterial efficacy, achieving a 99% inhibition rate of sessile Staphylococcus aureus cells after 5days. The corrosion data obtained by potentiodynamic polarization curves indicated that in comparison with 317L SS, the pitting potential and corrosion current density of 317L-Cu slightly decreased due to the addition of Cu. The 317L-Cu SS exhibited no cytotoxicity against zebrafish (Danio rerio) embryos. The experimental results in this study demonstrated that the new alloy has potential applications in medical and daily uses.}, } @article {pmid27608736, year = {2016}, author = {Hurlow, J and Blanz, E and Gaddy, JA}, title = {Clinical investigation of biofilm in non-healing wounds by high resolution microscopy techniques.}, journal = {Journal of wound care}, volume = {25 Suppl 9}, number = {Suppl 9}, pages = {S11-22}, pmid = {27608736}, issn = {0969-0700}, support = {IK2 BX001701/BX/BLRD VA/United States ; P30 DK058404/DK/NIDDK NIH HHS/United States ; UL1 RR024975/RR/NCRR NIH HHS/United States ; UL1 TR000445/TR/NCATS NIH HHS/United States ; }, mesh = {Adolescent ; Anti-Infective Agents, Local ; Bandages ; Biofilms/*growth & development ; *Debridement ; Humans ; Microscopy/*methods ; Wound Healing/*physiology ; Wound Infection/diagnosis/*microbiology ; }, abstract = {OBJECTIVE: The aim of this study was to analyse wound biofilm from a clinical perspective. Research has shown that biofilm is the preferred microbial phenotype in health and disease and is present in a majority of chronic wounds. Biofilm has been linked to chronic wound inflammation, impairment in granulation tissue and epithelial migration, yet there lacks the ability to confirm the clinical presence of biofilm. This study links the clinical setting with microscopic laboratory confirmation of the presence of biofilm in carefully selected wound debridement samples.

METHOD: Human wound debridement samples were collected from adult patients with chronic non-healing wounds who presented at the wound care centre. Sample choice was guided by an algorithm that was developed based on what is known about the characteristics of wound biofilm. The samples were then evaluated by light microscopy and scanning electron microscopy for the presence of biofilm. Details about subject history and treatment were recorded. Adherence to biofilm-based wound care (BBWC) strategies was inconsistent. Other standard antimicrobial dressings were used and no modern antiseptic wound dressings with the addition of proven antibiofilm agents were available for use.

RESULTS: Of the patients recruited, 75% of the macroscopic samples contained biofilm despite the prior use of modern antiseptic wound dressings and in some cases, systemic antibiotics. Wounds found to contain biofilm were not all acutely infected but biofilm was present when infection was noted. The clinical histories associated with positive samples were consistent with ideas presented in the algorithm used to guide sample selection.

CONCLUSION: Visual cues can be used by the clinician to guide suspicion of the presence of wound biofilm. This suspicion can be further enhanced with the use of a clinical algorithm. Standard antiseptic wound dressings used in this study demonstrated limited antibiofilm efficacy. This study also highlighted a need for the clinical team to focus on expiration of dressing action and consistent practice of BBWC strategies which includes the use of proven antibiofilm agents.}, } @article {pmid27604263, year = {2016}, author = {Phalak, P and Chen, J and Carlson, RP and Henson, MA}, title = {Metabolic modeling of a chronic wound biofilm consortium predicts spatial partitioning of bacterial species.}, journal = {BMC systems biology}, volume = {10}, number = {1}, pages = {90}, pmid = {27604263}, issn = {1752-0509}, support = {T32 GM108556/GM/NIGMS NIH HHS/United States ; U01 EB019416/EB/NIBIB NIH HHS/United States ; }, mesh = {*Biofilms ; Metabolic Flux Analysis ; *Models, Biological ; Pseudomonas aeruginosa/cytology/*metabolism/physiology ; Staphylococcus aureus/cytology/*metabolism/physiology ; Wounds and Injuries/*microbiology ; }, abstract = {BACKGROUND: Chronic wounds are often colonized by consortia comprised of different bacterial species growing as biofilms on a complex mixture of wound exudate. Bacteria growing in biofilms exhibit phenotypes distinct from planktonic growth, often rendering the application of antibacterial compounds ineffective. Computational modeling represents a complementary tool to experimentation for generating fundamental knowledge and developing more effective treatment strategies for chronic wound biofilm consortia.

RESULTS: We developed spatiotemporal models to investigate the multispecies metabolism of a biofilm consortium comprised of two common chronic wound isolates: the aerobe Pseudomonas aeruginosa and the facultative anaerobe Staphylococcus aureus. By combining genome-scale metabolic reconstructions with partial differential equations for metabolite diffusion, the models were able to provide both temporal and spatial predictions with genome-scale resolution. The models were used to analyze the metabolic differences between single species and two species biofilms and to demonstrate the tendency of the two bacteria to spatially partition in the multispecies biofilm as observed experimentally. Nutrient gradients imposed by supplying glucose at the bottom and oxygen at the top of the biofilm induced spatial partitioning of the two species, with S. aureus most concentrated in the anaerobic region and P. aeruginosa present only in the aerobic region. The two species system was predicted to support a maximum biofilm thickness much greater than P. aeruginosa alone but slightly less than S. aureus alone, suggesting an antagonistic metabolic effect of P. aeruginosa on S. aureus. When each species was allowed to enhance its growth through consumption of secreted metabolic byproducts assuming identical uptake kinetics, the competitiveness of P. aeruginosa was further reduced due primarily to the more efficient lactate metabolism of S. aureus. Lysis of S. aureus by a small molecule inhibitor secreted from P. aeruginosa and/or P. aeruginosa aerotaxis were predicted to substantially increase P. aeruginosa competitiveness in the aerobic region, consistent with in vitro experimental studies.

CONCLUSIONS: Our biofilm modeling approach allows the prediction of individual species metabolism and interspecies interactions in both time and space with genome-scale resolution. This study yielded new insights into the multispecies metabolism of a chronic wound biofilm, in particular metabolic factors that may lead to spatial partitioning of the two bacterial species. We believe that P. aeruginosa lysis of S. aureus combined with nutrient competition is a particularly relevant scenario for which model predictions could be tested experimentally.}, } @article {pmid27604080, year = {2016}, author = {Neufeld, BH and Reynolds, MM}, title = {Critical nitric oxide concentration for Pseudomonas aeruginosa biofilm reduction on polyurethane substrates.}, journal = {Biointerphases}, volume = {11}, number = {3}, pages = {031012}, doi = {10.1116/1.4962266}, pmid = {27604080}, issn = {1559-4106}, mesh = {Anti-Bacterial Agents/*metabolism ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; *Environmental Microbiology ; Microbial Viability/drug effects ; Nitric Oxide/*metabolism ; *Polyurethanes ; Pseudomonas aeruginosa/*drug effects/*physiology ; Temperature ; Time Factors ; }, abstract = {Bacterial colonies that reside on a surface, known as biofilms, are intrinsically impenetrable to traditional antibiotics, ultimately driving research toward an alternative therapeutic approach. Nitric oxide (NO) has gained attention for its biologically beneficial properties, particularly centered around its antibacterial capabilities. NO donors that can release the molecule under physiological conditions (such as S-nitrosothiols) can be utilized in clinical settings to combat bacterial biofilm infections. Herein the authors describe determining a critical concentration of NO necessary to cause >90% reduction of a Pseudomonas aeruginosa biofilm grown on medical grade polyurethane films. The biofilm was grown under optimal culture conditions [in nutrient broth media (NBM) at 37 °C] for 24 h before the addition of the NO donor S-nitrosoglutathione (GSNO) in NBM for an additional 24 h. The cellular viability of the biofilm after the challenge period was tested using varying concentrations of NO to determine the critical amount necessary to cause at least a 90% reduction in bacterial biofilm viability. The critical GSNO concentration was found to be 10 mM, which corresponds to 2.73 mM NO. Time kill experiments were performed on the 24 h biofilm using the critical amount of NO at 4, 8, 12, and 16 h and it was determined that the 90% biofilm viability reduction occurred at 12 h and was sustained for the entire 24 h challenge period. This critical concentration was subsequently tested for total NO release via a nitric oxide analyzer. The total amount of NO released over the 12 h challenge period was found to be 5.97 ± 0.66 × 10(-6) mol NO, which corresponds to 1.49 ± 0.17 μmol NO/ml NBM. This is the first identification of the critical NO concentration needed to elicit this biological response on a medically relevant polymer.}, } @article {pmid27604079, year = {2016}, author = {Rodgers, N and Murdaugh, A}, title = {Chlorhexidine-induced elastic and adhesive changes of Escherichia coli cells within a biofilm.}, journal = {Biointerphases}, volume = {11}, number = {3}, pages = {031011}, doi = {10.1116/1.4962265}, pmid = {27604079}, issn = {1559-4106}, mesh = {Anti-Infective Agents, Local/*metabolism ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Chlorhexidine/*metabolism ; Elasticity/*drug effects ; Escherichia coli/*drug effects/*physiology ; Microscopy, Atomic Force ; Spectrum Analysis ; }, abstract = {Chlorhexidine is a widely used, commercially available cationic antiseptic. Although its mechanism of action on planktonic bacteria has been well explored, far fewer studies have examined its interaction with an established biofilm. The physical effects of chlorhexidine on a biofilm are particularly unknown. Here, the authors report the first observations of chlorhexidine-induced elastic and adhesive changes to single cells within a biofilm. The elastic changes are consistent with the proposed mechanism of action of chlorhexidine. Atomic force microscopy and force spectroscopy techniques were used to determine spring constants and adhesion energy of the individual bacteria within an Escherichia coli biofilm. Medically relevant concentrations of chlorhexidine were tested, and cells exposed to 1% (w/v) and 0.1% more than doubled in stiffness, while those exposed to 0.01% showed no change in elasticity. Adhesion to the biofilm also increased with exposure to 1% chlorhexidine, but not for the lower concentrations tested. Given the prevalence of chlorhexidine in clinical and commercial applications, these results have important ramifications on biofilm removal techniques.}, } @article {pmid27601281, year = {2016}, author = {Vyas, N and Sammons, RL and Addison, O and Dehghani, H and Walmsley, AD}, title = {A quantitative method to measure biofilm removal efficiency from complex biomaterial surfaces using SEM and image analysis.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32694}, pmid = {27601281}, issn = {2045-2322}, mesh = {*Biocompatible Materials ; *Biofilms ; Microscopy, Electron, Scanning ; Surface Properties ; Ultrasonics ; }, abstract = {Biofilm accumulation on biomaterial surfaces is a major health concern and significant research efforts are directed towards producing biofilm resistant surfaces and developing biofilm removal techniques. To accurately evaluate biofilm growth and disruption on surfaces, accurate methods which give quantitative information on biofilm area are needed, as current methods are indirect and inaccurate. We demonstrate the use of machine learning algorithms to segment biofilm from scanning electron microscopy images. A case study showing disruption of biofilm from rough dental implant surfaces using cavitation bubbles from an ultrasonic scaler is used to validate the imaging and analysis protocol developed. Streptococcus mutans biofilm was disrupted from sandblasted, acid etched (SLA) Ti discs and polished Ti discs. Significant biofilm removal occurred due to cavitation from ultrasonic scaling (p < 0.001). The mean sensitivity and specificity values for segmentation of the SLA surface images were 0.80 ± 0.18 and 0.62 ± 0.20 respectively and 0.74 ± 0.13 and 0.86 ± 0.09 respectively for polished surfaces. Cavitation has potential to be used as a novel way to clean dental implants. This imaging and analysis method will be of value to other researchers and manufacturers wishing to study biofilm growth and removal.}, } @article {pmid27600501, year = {2016}, author = {Adcox, HE and Vasicek, EM and Dwivedi, V and Hoang, KV and Turner, J and Gunn, JS}, title = {Salmonella Extracellular Matrix Components Influence Biofilm Formation and Gallbladder Colonization.}, journal = {Infection and immunity}, volume = {84}, number = {11}, pages = {3243-3251}, pmid = {27600501}, issn = {1098-5522}, support = {R01 AI116917/AI/NIAID NIH HHS/United States ; R56 AI109002/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cell Survival/physiology ; Cytokines/metabolism ; Disease Models, Animal ; Extracellular Matrix/*metabolism ; Gallbladder/*microbiology ; Interleukin-10/metabolism ; Macrophages/microbiology ; Mice ; Mice, Transgenic ; Salmonella typhimurium/metabolism/pathogenicity/*physiology ; Tumor Necrosis Factor-alpha/metabolism ; Virulence/physiology ; }, abstract = {Salmonella enterica serovar Typhi, the causative agent of typhoid fever in humans, forms biofilms encapsulated by an extracellular matrix (ECM). Biofilms facilitate colonization and persistent infection in gallbladders of humans and mouse models of chronic carriage. Individual roles of matrix components have not been completely elucidated in vitro or in vivo To examine individual functions, strains of Salmonella enterica serovar Typhimurium, the murine model of S Typhi, in which various ECM genes were deleted or added, were created to examine biofilm formation, colonization, and persistence in the gallbladder. Studies show that curli contributes most significantly to biofilm formation. Expression of Vi antigen decreased biofilm formation in vitro and virulence and bacterial survival in vivo without altering the examined gallbladder pro- or anti-inflammatory cytokines. Oppositely, loss of all ECM components (ΔwcaM ΔcsgA ΔyihO ΔbcsE) increased virulence and bacterial survival in vivo and reduced gallbladder interleukin-10 (IL-10) levels. Colanic acid and curli mutants had the largest defects in biofilm-forming ability and contributed most significantly to the virulence increase of the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant strain. While the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant was not altered in resistance to complement or growth in macrophages, it attached and invaded macrophages better than the wild-type (WT) strain. These data suggest that ECM components have various levels of importance in biofilm formation and gallbladder colonization and that the ECM diminishes disseminated disease in our model, perhaps by reducing cell attachment/invasion and dampening inflammation by maintaining/inducing IL-10 production. Understanding how ECM components aid acute disease and persistence could lead to improvements in therapeutic treatment of typhoid fever patients.}, } @article {pmid27598657, year = {2018}, author = {Martínez, A and Catalán, A and Rojas, N and Torres, V and Acuña, M}, title = {In Vitro Effectiveness of a Terpenic Denture Cleanser on Old Biofilm Surfaces.}, journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists}, volume = {27}, number = {1}, pages = {57-62}, doi = {10.1111/jopr.12531}, pmid = {27598657}, issn = {1532-849X}, mesh = {Biofilms/*drug effects ; Denture Cleansers/*pharmacology ; Humans ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Terpenes/*pharmacology ; }, abstract = {PURPOSE: To assess the effects of terpenic denture cleanser on denture biofilm removal using scanning electron microscopy (SEM).

MATERIALS AND METHODS: The internal surface biofilm of four maxillary dentures was elucidated with Caristop-revelador Dual Tone, and 40 blue-stained specimens (0.6 cm × 0.4 cm × 2 mm) were obtained. These specimens were randomly assigned to one of the following four groups of 10 specimens each: control, Eci Clean, Fitty Dent, and terpenic denture cleanser. The period of immersion in each solution was 12 hours. Biofilm removal was evaluated using SEM, and morphologically varying areas of the SEM images were quantified with Imaris software. The data were analyzed using Kolmogorov-Smirnov, t-tests, ANOVA, and Tamhane's tests (p = 0.05).

RESULTS: Data revealed that terpenic denture cleanser removed significantly more biofilm than any other treatment examined in this study. The t-tests revealed significant differences in the clean area that resulted from the use of the terpenic cleanser compared with the clean area that resulted from the use of Eci Clean (p = 0.013). Fitty Dent was the least effective and left dirty acrylic resin. The average areas with few removed layers were 59.3%, 43.3%, and 9.5% in Fitty Dent, Eci Clean, and terpenic cleanser groups, respectively. Tamhane's tests indicated that the Eci Clean and Fitty Dent groups were significantly different from the 0.5% terpenic cleanser group (p = 0.008).

CONCLUSION: The terpenic denture cleanser was effective in removing denture biofilm.}, } @article {pmid27598130, year = {2016}, author = {de Oliveira, A and Cataneli Pereira, V and Pinheiro, L and Moraes Riboli, DF and Benini Martins, K and Ribeiro de Souza da Cunha, Mde L}, title = {Antimicrobial Resistance Profile of Planktonic and Biofilm Cells of Staphylococcus aureus and Coagulase-Negative Staphylococci.}, journal = {International journal of molecular sciences}, volume = {17}, number = {9}, pages = {}, pmid = {27598130}, issn = {1422-0067}, mesh = {Anti-Bacterial Agents/classification/*pharmacology ; Biofilms/*drug effects ; Coagulase/genetics/metabolism ; *Drug Resistance, Microbial ; Plankton/*drug effects ; Staphylococcus aureus/classification/*drug effects/enzymology ; }, abstract = {The objective of the present study was to determine the antimicrobial resistance profile of planktonic and biofilm cells of Staphylococcus aureus and coagulase-negative staphylococci (CoNS). Two hundred Staphylococcus spp. strains were studied, including 50 S. aureus and 150 CoNS strains (50 S. epidermidis, 20 S. haemolyticus, 20 S. warneri, 20 S. hominis, 20 S. lugdunensis, and 20 S. saprophyticus). Biofilm formation was investigated by adherence to polystyrene plates. Positive strains were submitted to the broth microdilution method to determine the minimum inhibitory concentration (MIC) for planktonic and biofilm cells and the minimal bactericidal concentration for biofilm cells (MBCB). Forty-nine Staphylococcus spp. strains (14 S. aureus, 13 S. epidermidis, 13 S. saprophyticus, 3 S. haemolyticus, 1 S. hominis, 3 S. warneri, and 2 S. lugdunensis) were biofilm producers. These isolates were evaluated regarding their resistance profile. Determination of planktonic cell MIC identified three (21.4%) S. aureus strains that were resistant to oxacillin and six (42.8%) that were resistant to erythromycin. Among the CoNS, 31 (88.6%) strains were resistant to oxacillin, 14 (40%) to erythromycin, 18 (51.4%) to gentamicin, and 8 (22.8%) to sulfamethoxazole/trimethoprim. None of the planktonic isolates were resistant to vancomycin or linezolid. MICs were 2-, 4-, 8-, and up to 16-fold higher for biofilm cells than for planktonic cells. This observation was more common for vancomycin and erythromycin. The MBCB ranged from 8 to >256 µg/mL for oxacillin, 128 to >128 µg/mL for vancomycin, 256 to >256 µg/mL for erythromycin and gentamicin, >64 µg/mL for linezolid, and 32/608 to >32/608 µg/mL for sulfamethoxazole/trimethoprim. The results showed considerably higher MICs for S. aureus and CoNS biofilm cells compared to planktonic cells. Analysis of MBCM confirmed that even high concentrations of vancomycin were unable to eliminate the biofilms of S. aureus and CoNS species. Linezolid was the most effective drug in inhibiting staphylococci in the biofilm, without an increase in the MIC, when compared to planktonic cells. None of the isolates were resistant to this drug.}, } @article {pmid27597778, year = {2017}, author = {Maharjan, P and Huff, G and Zhang, W and Watkins, S}, title = {Biofilm growth on polyvinylchloride surface incubated in suboptimal microbial warm water and effect of sanitizers on biofilm removal post biofilm formation.}, journal = {Poultry science}, volume = {96}, number = {1}, pages = {83-87}, doi = {10.3382/ps/pew284}, pmid = {27597778}, issn = {1525-3171}, mesh = {Animal Husbandry ; Animals ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects/*growth & development ; Chickens/physiology ; Disinfectants/*pharmacology ; Hot Temperature ; *Polyvinyl Chloride ; Wastewater/*microbiology ; }, abstract = {An in vitro experiment was conducted to understand the nature of biofilm growth on polyvinyl chloride (PVC) surface when exposed to suboptimal-quality microbial water (>4 log10 cfu/mL) obtained from a poultry drinking water source mimicking water in waterlines during the first week of poultry brooding condition. PVC sections (internal surface area of 15.16 cm[2]) were utilized in the study to grow biofilm. After a 7-d test period, test coupons with 7-day-old biofilm were transferred into autoclaved municipal water and then treated with either chlorine-based or hydrogen peroxide-based sanitizer at bird drinking water rate, to see the impact on removal of biofilm formed on test coupons. Two trials (T1 and T2) were conducted. Test coupons used in T1 and T2 had the bacterial growth of 3.67 (SEM 0.04) and 3.97 (SEM 0.11) log10 cfu/cm[2] on d 7. After sanitizer application, chlorine-based sanitizer removed bacteria in biofilm completely (0 cfu/cm[2]) within 24 h post treatment whereas hydrogen peroxide-based sanitizer reduced the counts to 1.68 log10 cfu/cm[2] (P < 0.05) by 48 h post sanitizer application. Control remained the same (P > 0.05). Results indicated that biofilm formation can occur quickly under suboptimal water condition on PVC surface, and sanitizer application helped mitigate already formed biofilm, yet chlorine proved to be more effective than hydrogen peroxide.}, } @article {pmid27597777, year = {2016}, author = {Wang, Y and Yi, L and Wang, Y and Wang, Y and Cai, Y and Zhao, W and Ding, C}, title = {Isolation, phylogenetic group, drug resistance, biofilm formation, and adherence genes of Escherichia coli from poultry in central China.}, journal = {Poultry science}, volume = {95}, number = {12}, pages = {2895-2901}, doi = {10.3382/ps/pew252}, pmid = {27597777}, issn = {1525-3171}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/*genetics/physiology ; *Biofilms/growth & development ; Chickens/*microbiology ; China/epidemiology ; Drug Resistance, Bacterial/genetics ; Escherichia coli/drug effects/*genetics/isolation & purification ; Escherichia coli Infections/drug therapy/epidemiology/microbiology/*veterinary ; Genes, Bacterial/genetics/physiology ; Phylogeny ; Poultry Diseases/drug therapy/epidemiology/*microbiology ; }, abstract = {The isolation and identification, genetic typing, antibiotic sensitivity, and biofilm formation of avian Escherichia coli in central China was studied. A total of 256 isolates of E. coli were obtained, and classified into groups: A (50.78%, 130/256), B1 (11.72%, 30/256), B2 (17.58%, 45/256), and D (19.92%, 51/256). Drug susceptibility testing revealed that the strains showed a high drug resistance rate against penicillin, aztreonam, rifampicin, kanamycin, clindamycin, and gentamicin, with 92.19% of strains exhibiting multi-drug resistance. A biofilm assay revealed that 81.64% of isolates could form biofilms. Of the total isolates, 25.39% of isolates showed strong biofilm-formation ability, 31.25% showed moderate biofilm-formation ability, 28.90% showed weak biofilm-formation ability, and 18.36% were unable to form biofilms. Most adhesion-associated genes were distributed among 5 or 8 genes in strong biofilm-forming ability isolates. However, adhesion-associated genes distributed among 1 or 4 genes were found in weak biofilm-forming ability isolates and non-ability isolates. The results showed a high drug resistance rate and biofilm formation ability in E.coli strains isolated from poultry. The isolates which have strong biofilm-forming ability were mostly belong to pathogenic E. coli (B2, D). Furthermore, it was the first report to demonstrate a positive correlation between adhesion-encoding genes and biofilms phenotype.}, } @article {pmid27597232, year = {2017}, author = {Chen, X and Zhang, R and Takada, A and Iwatani, S and Oka, C and Kitamoto, T and Kajiwara, S}, title = {The role of Bgl2p in the transition to filamentous cells during biofilm formation by Candida albicans.}, journal = {Mycoses}, volume = {60}, number = {2}, pages = {96-103}, doi = {10.1111/myc.12554}, pmid = {27597232}, issn = {1439-0507}, mesh = {Basic Helix-Loop-Helix Transcription Factors/genetics ; Biofilms/*growth & development ; Candida albicans/enzymology/*genetics/*physiology/ultrastructure ; Candidiasis ; DNA-Binding Proteins/genetics ; Fungal Proteins/genetics ; Gene Deletion ; Glucan Endo-1,3-beta-D-Glucosidase/chemistry/*genetics/metabolism ; Hyphae/genetics/ultrastructure ; Microscopy, Electron, Scanning ; Mutation ; Polymerase Chain Reaction ; Transcription Factors/genetics ; }, abstract = {The fungal pathogen Candida albicans undergoes a transition from yeast cells to filamentous cells that is related to its pathogenicity. The complex multicellular processes involved in biofilm formation by this fungus also include this transition. In this work, we investigated the morphological role of the Bgl2 protein (Bgl2p) in the transition to filamentous cells during biofilm formation by C. albicans. Bgl2p has been identified as a β-1, 3-glucosyltransferase, and transcription of the CaBGL2 gene is upregulated during biofilm formation. We used scanning electron microscopy to observe the microstructure of a bgl2 null mutant during biofilm formation and found a delay in the transition to filamentous cells in the premature phase (24 hours) of biofilm formation. Deletion of the CaBGL2 gene led to a decrease in the expression of CPH2 and TEC1, which encode transcription factors required for the transition to the filamentous form. These findings indicate that Bgl2p plays a role in the transition to filamentous cells during biofilm formation by C. albicans.}, } @article {pmid27596811, year = {2016}, author = {Viszwapriya, D and Subramenium, GA and Prithika, U and Balamurugan, K and Pandian, SK}, title = {Betulin inhibits virulence and biofilm of Streptococcus pyogenes by suppressing ropB core regulon, sagA and dltA.}, journal = {Pathogens and disease}, volume = {74}, number = {7}, pages = {}, doi = {10.1093/femspd/ftw088}, pmid = {27596811}, issn = {2049-632X}, abstract = {The present study demonstrates the antivirulence potential of betulin, an abundantly available triterpenoid against Streptococcus pyogenes, a multivirulent and exclusive human pathogen. Crystal violet assay and microscopic examination revealed that betulin (100 μg mL[-1]) exhibits surface-independent antibiofilm activity and mitigates extracellular polymeric substance production. Betulin treatment enhanced the rate of auto-aggregation in liquid medium. Results of real-time PCR and biochemical assays demonstrated that betulin suppresses the expression of ropB core regulon, sagA and dltA, which correspondingly affects SpeB production, hemolysis and cell surface hydrophobicity for the observed impairment in virulence and biofilm formation. dltA downregulation also affected the production of M protein, making betulin-treated cells more susceptible to phagocytosis. The non-toxic nature of betulin and its antivirulence potential against S. pyogenes were manifested in vivo in Caenorhabditis elegans This study reveals the prospective role of betulin as therapeutic agent for the prevention and treatment of streptococcal infections.}, } @article {pmid27595541, year = {2016}, author = {Henne, K and Gunesch, AP and Walther, C and Meyer-Lueckel, H and Conrads, G and Esteves-Oliveira, M}, title = {Analysis of Bacterial Activity in Sound and Cariogenic Biofilm: A Pilot in vivo Study.}, journal = {Caries research}, volume = {50}, number = {5}, pages = {480-488}, doi = {10.1159/000448485}, pmid = {27595541}, issn = {1421-976X}, mesh = {Actinobacteria/genetics/*metabolism ; Adult ; Bifidobacterium/genetics/*metabolism ; Biofilms/*growth & development ; Colony Count, Microbial ; DNA, Bacterial/isolation & purification ; Dental Caries/*microbiology ; Dental Plaque/microbiology ; Female ; Fusobacteria/genetics/*metabolism ; Humans ; Lactobacillus/genetics/*metabolism ; Male ; Middle Aged ; Pilot Projects ; RNA, Bacterial/isolation & purification ; RNA, Ribosomal, 16S/genetics ; Streptococcus mutans/genetics/*metabolism ; }, abstract = {Dental caries is a multifactorial disease with many associated microbial taxa, but only a few are notably contributing to acidogenicity. The ribosome number and the corresponding 16S ribosomal RNA (rRNA) concentration are considered a molecular indicator for general metabolic activity of bacteria, as they are elevated with increased anabolic and catabolic activities. We hypothesize that the activity of aciduric/acidogenic bacterial taxa, reflected by a rise in ribosomal counts, could resolve differences between plaque biofilm from sound surfaces and caries lesions. The included subjects were allocated to two groups: caries-free (CF) or caries-active (CA). CF subjects presented one donor site, namely one sound surface (CFS, n = 10), whereas CA subjects presented two donor sites: a cavitated lesion with an ICDAS score of 5-6 (CAC, n = 13), and a sound reference surface (CAS, n = 13). Four aciduric/acidogenic bacterial taxa (Streptococcus mutans, lactobacilli, Bifidobacterium dentium, and Scardovia wiggsiae) and one asaccharolytic taxon (fusobacteria) as a contrast were selected. 16S rRNA and 16S rRNA genes were quantified by quantitative PCR. Based on these parameters, bacterial and ribosomal counts, as well as relative activities were calculated as the quotient of relative ribosomal abundance and relative genome abundance. Caries-associated bacteria showed the highest relative activity in caries lesions (e.g. lactobacilli CAC: 177.5 ± 46.0%) and lower activities on sound surfaces (e.g. lactobacilli CAS: 96.3 ± 31.5%), whereas asaccharolytic fusobacteria were most active on sound surfaces and less active in caries lesions (CFS: 275.7 ± 171.1%; CAS: 205.8 ± 114.3%; CAC: 51.1 ± 19.0%). Thus, the present study suggests different activity patterns for biofilms from CF and CA individuals.}, } @article {pmid27594311, year = {2016}, author = {Hurlow, J}, title = {Understanding biofilm: what a community nurse should know.}, journal = {British journal of community nursing}, volume = {21 Suppl 9}, number = {}, pages = {S26-33}, doi = {10.12968/bjcn.2016.21.Sup9.S26}, pmid = {27594311}, issn = {1462-4753}, mesh = {Biofilms/*growth & development ; *Health Knowledge, Attitudes, Practice ; Humans ; Nursing Staff/*education ; Wound Healing/*physiology ; Wound Infection/*microbiology ; }, abstract = {The job of a community nurse involves effort to support wound healing. It is now well accepted in wound science that the presence of bacterial biofilm is an important risk factor for wound chronicity. Therefore, this problem is important for the community nurse to assess and address in order to avoid cost waste and to promote optimal patient quality of life. However, there exist many questions about exactly how biofilm impairs healing, how its presence can be clinically diagnosed in a wound, and how this barrier to healing can be most cost effectively treated. The goal of this article is to provide the front-line, community wound care nurse with the practical understanding needed to cost effectively address these challenges in the clinical setting.}, } @article {pmid27589264, year = {2016}, author = {Dashper, SG and Catmull, DV and Liu, SW and Myroforidis, H and Zalizniak, I and Palamara, JE and Huq, NL and Reynolds, EC}, title = {Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0162322}, pmid = {27589264}, issn = {1932-6203}, mesh = {Biofilms/*drug effects/growth & development ; Caseins/*pharmacology ; Dental Caries/prevention & control ; *Glass Ionomer Cements ; Humans ; Streptococcus mutans/*drug effects/growth & development ; }, abstract = {Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.}, } @article {pmid27585076, year = {2016}, author = {Poimenidou, SV and Chrysadakou, M and Tzakoniati, A and Bikouli, VC and Nychas, GJ and Skandamis, PN}, title = {Variability of Listeria monocytogenes strains in biofilm formation on stainless steel and polystyrene materials and resistance to peracetic acid and quaternary ammonium compounds.}, journal = {International journal of food microbiology}, volume = {237}, number = {}, pages = {164-171}, doi = {10.1016/j.ijfoodmicro.2016.08.029}, pmid = {27585076}, issn = {1879-3460}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Colony Count, Microbial ; Disinfectants/chemistry/pharmacology ; Food Handling/*methods ; Food Microbiology ; Hydrophobic and Hydrophilic Interactions ; Listeria monocytogenes/*drug effects ; Microbial Sensitivity Tests ; Peracetic Acid/*chemistry/pharmacology ; Polystyrenes/*chemistry ; Principal Component Analysis ; Quaternary Ammonium Compounds/pharmacology ; *Stainless Steel ; Temperature ; }, abstract = {Listeria monocytogenes is a foodborne pathogen able to tolerate adverse conditions by forming biofilms or by deploying stress resistant mechanisms, and thus manages to survive for long periods in food processing plants. This study sought to investigate the correlation between biofilm forming ability, tolerance to disinfectants and cell surface characteristics of twelve L. monocytogenes strains. The following attributes were evaluated: (i) biofilm formation by crystal violet staining method on polystyrene, and by standard cell enumeration on stainless steel and polystyrene; (ii) hydrophobicity assay using solvents; (iii) minimum inhibitory concentration (MIC) and biofilm eradication concentration (BEC) of peracetic acid (PAA) and quaternary ammonium compounds (QACs), and (iv) resistance to sanitizers (PAA 2000ppm; QACs 500ppm) of biofilms on polystyrene and stainless steel. After 72h of incubation, higher biofilm levels were formed in TSB at 20°C, followed by TSB at 37°C (P=0.087) and diluted TSB 1/10 at both 20 (P=0.005) and 37°C (P=0.004). Cells grown at 30°C to the stationary phase had significant electron donating nature and a low hydrophobicity, while no significant correlation of cell surface properties to biofilm formation was observed. Strains differed in MICPAA and BECPAA by 24- and 15-fold, respectively, while a positive correlation between MICPAA and BECPAA was observed (P=0.02). The MICQACs was positively correlated with the biofilm-forming ability on stainless steel (P=0.03). Regarding the impact of surface type, higher biofilm populations were enumerated on polystyrene than on stainless steel, which were also more tolerant to disinfectants. Among all strains, the greatest biofilm producer was a persistent strain with significant tolerance to QACs. These results may contribute to better understanding of L. monocytogenes behavior and survival on food processing surfaces.}, } @article {pmid27582732, year = {2016}, author = {Ren, H and Wu, J and Colletta, A and Meyerhoff, ME and Xi, C}, title = {Efficient Eradication of Mature Pseudomonas aeruginosa Biofilm via Controlled Delivery of Nitric Oxide Combined with Antimicrobial Peptide and Antibiotics.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1260}, pmid = {27582732}, issn = {1664-302X}, support = {R01 EB000783/EB/NIBIB NIH HHS/United States ; R56 HL119403/HL/NHLBI NIH HHS/United States ; }, abstract = {Fast eradication of mature biofilms is the 'holy grail' in the clinical management of device-related infections. Endogenous nitric oxide (NO) produced by macrophages plays an important role in host defense against intracellular pathogens, and NO is a promising agent in preventing biofilms formation in vitro. However, the rate of delivery of NO by various NO donors (e.g., diazeniumdiolates, S-nitrosothiols, etc.) is difficult to control, which hinders fundamental studies aimed at understanding the role of NO in biofilm control. In this study, by using a novel precisely controlled electrochemical NO releasing catheter device, we examine the effect of physiological levels of NO on eradicating mature Pseudomonas aeruginosa biofilm (7 days), as well as the potential application of the combination of NO with antimicrobial agents. It is shown that physiological levels of NO exhibit mixed effects of killing bacteria and dispersing ambient biofilm. The overall biofilm-eradicating effect of NO is quite efficient in a dose-dependent manner over a 3 h period of NO treatment. Moreover, NO also greatly enhances the efficacy of antimicrobial agents, including human beta-defensin 2 (BD-2) and several antibiotics, in eradicating biofilm and its detached cells, which otherwise exhibited high recalcitrance to these antimicrobial agents. The electrochemical NO release technology offers a powerful tool in evaluating the role of NO in biofilm control as well as a promising approach when combined with antimicrobial agents to treat biofilm-associated infections in hospital settings, especially infections resulting from intravascular catheters.}, } @article {pmid27582320, year = {2016}, author = {Schulte, T and Mikaelsson, C and Beaussart, A and Kikhney, A and Deshmukh, M and Wolniak, S and Pathak, A and Ebel, C and Löfling, J and Fogolari, F and Henriques-Normark, B and Dufrêne, YF and Svergun, D and Nygren, PÅ and Achour, A}, title = {The BR domain of PsrP interacts with extracellular DNA to promote bacterial aggregation; structural insights into pneumococcal biofilm formation.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32371}, pmid = {27582320}, issn = {2045-2322}, mesh = {*Bacterial Adhesion ; Bacterial Proteins/*chemistry/*metabolism ; Biofilms/*growth & development ; Cell Membrane/metabolism ; DNA, Bacterial/chemistry/*metabolism ; Furin/metabolism ; Gene Expression ; Nucleic Acid Conformation ; Protein Domains ; Protein Multimerization ; Protein Structure, Secondary ; Scattering, Small Angle ; Streptococcus pneumoniae/*cytology/*metabolism ; X-Ray Diffraction ; }, abstract = {The major human pathogen Streptococcus pneumoniae is a leading cause of disease and death worldwide. Pneumococcal biofilm formation within the nasopharynx leads to long-term colonization and persistence within the host. We have previously demonstrated that the capsular surface-associated pneumococcal serine rich repeat protein (PsrP), key factor for biofilm formation, binds to keratin-10 (KRT10) through its microbial surface component recognizing adhesive matrix molecule (MSCRAMM)-related globular binding region domain (BR187-385). Here, we show that BR187-385 also binds to DNA, as demonstrated by electrophoretic mobility shift assays and size exclusion chromatography. Further, heterologous expression of BR187-378 or the longer BR120-378 construct on the surface of a Gram-positive model host bacterium resulted in the formation of cellular aggregates that was significantly enhanced in the presence of DNA. Crystal structure analyses revealed the formation of BR187-385 homo-dimers via an intermolecular β-sheet, resulting in a positively charged concave surface, shaped to accommodate the acidic helical DNA structure. Furthermore, small angle X-ray scattering and circular dichroism studies indicate that the aggregate-enhancing N-terminal region of BR120-166 adopts an extended, non-globular structure. Altogether, our results suggest that PsrP adheres to extracellular DNA in the biofilm matrix and thus promotes pneumococcal biofilm formation.}, } @article {pmid27580333, year = {2016}, author = {Serray, B and Oufrid, S and Hannaoui, I and Bourjilate, F and Soraa, N and Mliji, M and Sobh, M and Hammoumi, A and Timinouni, M and El Azhari, M}, title = {Genes encoding adhesion factors and biofilm formation in methicillin-resistant Staphylococcus aureus in Morocco.}, journal = {Journal of infection in developing countries}, volume = {10}, number = {8}, pages = {863-869}, doi = {10.3855/jidc.8361}, pmid = {27580333}, issn = {1972-2680}, mesh = {Adhesins, Bacterial/*genetics ; *Bacterial Adhesion ; Bacteriological Techniques ; Biofilms/*growth & development ; Carrier State/epidemiology/*microbiology ; Child ; Child, Preschool ; *Genes, Bacterial ; Hospitals ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/isolation & purification/*physiology ; Morocco/epidemiology ; Polymerase Chain Reaction ; Staphylococcal Infections/epidemiology/*microbiology ; }, abstract = {INTRODUCTION: Infections involving methicillin-resistant Staphylococcus aureus (MRSA) remain a serious threat to hospitalized patients worldwide. MRSA is characterized by recalcitrance to antimicrobial therapy, which is a function not only of widespread antimicrobial resistance, but also the capacity to form biofilms. The present study evaluated the presence of genes encoding adhesion factors and the biofilm-forming capacity in MRSA.

METHODOLOGY: In this study, 53 isolates of MRSA, recovered from December 2010 to May 2014 in a mother and child hospital, CHU Mohamed VI in Marrakech, Morocco, were screened for the presence of bap and ica genes associated with biofilm formation, and for bbp, cna, ebpS, eno, fib, fnbA, fnbB, clfA, and clfB genes that encode microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). The biofilm formation assay was performed in 96-well microtiter polystyrene plates. The presence of genes was determined by polymerase chain reaction (PCR).

RESULTS: An association was found between icaD gene detection and biofilm formation; 100% of the strains harbored icaD and produced biofilm. None of the isolates harbored bap or bbp. Furthermore, 96.23% isolates were positive for fnbA, 60.37% for eno, 43.39% for clfA and clfB, 11.32% for cna, 9.34% for ebpS, 5.66% for fib, and 1.89% for fnbA.

CONCLUSIONS: Our findings showed that the MRSA carriage in Marrakech children was high. The genetic variations of adhesion genes require further investigation.}, } @article {pmid27580265, year = {2016}, author = {Zhang, S and Song, HL and Yang, XL and Yang, KY and Wang, XY}, title = {Effect of electrical stimulation on the fate of sulfamethoxazole and tetracycline with their corresponding resistance genes in three-dimensional biofilm-electrode reactors.}, journal = {Chemosphere}, volume = {164}, number = {}, pages = {113-119}, doi = {10.1016/j.chemosphere.2016.08.076}, pmid = {27580265}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/chemistry ; Anti-Infective Agents/*chemistry ; *Biofilms ; Bioreactors ; Drug Resistance, Microbial/*genetics ; Electrochemical Techniques ; Microbiota/*genetics ; Oxidoreductases/metabolism ; Sulfamethoxazole/*chemistry ; Tetracycline/*chemistry ; Tetracycline Resistance/genetics ; Waste Disposal, Fluid/*methods ; }, abstract = {Three-dimensional biofilm-electrode reactors (3D-BERs), which possess a large effective area to drive the reductive degradation of contaminants, have recently attracted attention for wastewater treatment. There have been few studies of the potential and risks of the application of this system on the removal of antibiotics. Here four 3D-BERs were designed to initially assess the potential for electrical stimulation to remove sulfamethoxazole (SMX), tetracycline (TC) and chemical oxygen demand, and to study the fate of the corresponding antibiotic resistance genes. The results indicated that the 3D-BER could significantly reduce antibiotic concentrations in wastewater, achieving removal rates of 88.9-93.5% and 89.3-95.6% for SMX and TC, respectively. The concentrations of target genes (sulI, sulII, sulIII, tetA, tetC, tetO, tetQ, and tetW) in a granular-activated carbon (GAC) cathode were higher than those in a GAC anode in the 3D-BR (reactor with biological sludge and no voltage) and 3D-BER. An obvious increasing trend in the relative abundances of all target genes was observed in the GAC. A low current density could not increase the development of sul and tet genes in the 3D-BER. The total resistance was in the following order: 3D-BER > 3D-BR > 3D-ER (reactor with 0.8 V and without biological sludge). In addition, the dehydrogenase activity of the microorganisms in the 3D-BER was significantly higher than in the 3D-BR (p < 0.05). High-throughput sequencing revealed that the microbial communities and relative abundance at the phyla level were affected by current stimulation.}, } @article {pmid27578208, year = {2017}, author = {Xu, D and Xia, J and Zhou, E and Zhang, D and Li, H and Yang, C and Li, Q and Lin, H and Li, X and Yang, K}, title = {Accelerated corrosion of 2205 duplex stainless steel caused by marine aerobic Pseudomonas aeruginosa biofilm.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {113}, number = {}, pages = {1-8}, doi = {10.1016/j.bioelechem.2016.08.001}, pmid = {27578208}, issn = {1878-562X}, mesh = {Aerobiosis ; *Biofilms ; Corrosion ; Kinetics ; Pseudomonas aeruginosa/metabolism/*physiology ; Stainless Steel/*chemistry ; Surface Properties ; }, abstract = {Microbiologically influenced corrosion (MIC) of 2205 duplex stainless steel (DSS) in the presence of Pseudomonas aeruginosa was investigated through electrochemical and surface analyses. The electrochemical results showed that P. aeruginosa significantly reduced the corrosion resistance of 2205 DSS. Confocal laser scanning microscopy (CLSM) images showed that the depths of the largest pits on 2205 DSS with and without P. aeruginosa were 14.0 and 4.9μm, respectively, indicating that the pitting corrosion was accelerated by P. aeruginosa. X-ray photoelectron spectroscopy (XPS) results revealed that CrO3 and CrN formed on the 2205 DSS surface in the presence of P. aeruginosa.}, } @article {pmid27574814, year = {2016}, author = {Lillicrap, A and Macken, A and Wennberg, AC and Grung, M and Rundberget, JT and Fredriksen, L and Scheie, AA and Benneche, T and d'Auriac, MA}, title = {Environmental fate and effects of novel quorum sensing inhibitors that can control biofilm formation.}, journal = {Chemosphere}, volume = {164}, number = {}, pages = {52-58}, doi = {10.1016/j.chemosphere.2016.08.083}, pmid = {27574814}, issn = {1879-1298}, mesh = {Animals ; Aquatic Organisms/drug effects/growth & development ; Biofilms/*drug effects/*growth & development ; Crustacea/drug effects/growth & development ; Diatoms/drug effects/growth & development ; Ecotoxicology ; Models, Theoretical ; Quantitative Structure-Activity Relationship ; Quorum Sensing/*drug effects ; Thiophenes/chemistry/*pharmacology/toxicity ; }, abstract = {The formation of bacterial biofilms can have negative impacts on industrial processes and are typically difficult to control. The increase of antibiotic resistance, in combination with the requirement for more environmentally focused approaches, has placed pressure on industry and the scientific community to reassess biofilm control strategies. The discovery of bacterial quorum sensing, as an important mechanism in biofilm formation, has led to the development of new substances (such as halogenated thiophenones) to inhibit the quorum sensing process. However, there are currently limited data regarding the biodegradability or ecotoxicity of these substances. To assess the environmental fate and effects of thiophenones capable of quorum sensing inhibition, candidate substances were first identified that have potentially high biodegradability and low ecotoxicity using quantitative structure activity relationships. Subsequent confirmatory hazard assessment of these substances, using a marine alga and a marine crustacean, indicated that these estimates were significantly under predicted with acute toxicity values more than three orders of magnitude lower than anticipated combined with limited biodegradability. Therefore, although these quorum sensing inhibitors appear a promising approach to control biofilms, they may also have environmental impacts on certain aquatic organisms.}, } @article {pmid27572513, year = {2016}, author = {Ryu, EJ and Sim, J and Sim, J and Lee, J and Choi, BK}, title = {D-Galactose as an autoinducer 2 inhibitor to control the biofilm formation of periodontopathogens.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {54}, number = {9}, pages = {632-637}, pmid = {27572513}, issn = {1976-3794}, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Calcium-Binding Proteins/genetics/metabolism ; Fusobacterium nucleatum/*drug effects/genetics/metabolism ; Galactose/metabolism/*pharmacology ; Homoserine/*analogs & derivatives/antagonists & inhibitors/metabolism ; Humans ; Lactones/*antagonists & inhibitors/metabolism ; Monosaccharide Transport Proteins/genetics/metabolism ; Periodontitis/*microbiology ; Periplasmic Binding Proteins/genetics/metabolism ; Porphyromonas gingivalis/*drug effects/physiology ; Vibrio/drug effects/physiology ; }, abstract = {Autoinducer 2 (AI-2) is a quorum sensing molecule to which bacteria respond to regulate various phenotypes, including virulence and biofilm formation. AI-2 plays an important role in the formation of a subgingival biofilm composed mostly of Gram-negative anaerobes, by which periodontitis is initiated. The aim of this study was to evaluate D-galactose as an inhibitor of AI-2 activity and thus of the biofilm formation of periodontopathogens. In a search for an AI-2 receptor of Fusobacterium nucleatum, D-galactose binding protein (Gbp, Gene ID FN1165) showed high sequence similarity with the ribose binding protein (RbsB), a known AI-2 receptor of Aggregatibacter actinomycetemcomitans. D-Galactose was evaluated for its inhibitory effect on the AI-2 activity of Vibrio harveyi BB152 and F. nucleatum, the major coaggregation bridge organism, which connects early colonizing commensals and late pathogenic colonizers in dental biofilms. The inhibitory effect of D-galactose on the biofilm formation of periodontopathogens was assessed by crystal violet staining and confocal laser scanning microscopy in the absence or presence of AI-2 and secreted molecules of F. nucleatum. D-Galactose significantly inhibited the AI-2 activity of V. harveyi and F. nucleatum. In addition, D-galactose markedly inhibited the biofilm formation of F. nucleatum, Porphyromonas gingivalis, and Tannerella forsythia induced by the AI-2 of F. nucleatum without affecting bacterial growth. Our results demonstrate that the Gbp may function as an AI-2 receptor and that galactose may be used for prevention of the biofilm formation of periodontopathogens by targeting AI-2 activity.}, } @article {pmid27571696, year = {2016}, author = {Watters, C and Fleming, D and Bishop, D and Rumbaugh, KP}, title = {Host Responses to Biofilm.}, journal = {Progress in molecular biology and translational science}, volume = {142}, number = {}, pages = {193-239}, doi = {10.1016/bs.pmbts.2016.05.007}, pmid = {27571696}, issn = {1878-0814}, support = {R15 AI105763/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biofilms/drug effects ; *Host-Pathogen Interactions/drug effects ; Humans ; Immune System/drug effects/microbiology ; Models, Biological ; Probiotics/pharmacology ; Skin/drug effects/immunology ; }, abstract = {From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand.}, } @article {pmid27569533, year = {2016}, author = {Aliramezani, A and Douraghi, M and Hajihasani, A and Mohammadzadeh, M and Rahbar, M}, title = {Clonal relatedness and biofilm formation of OXA-23-producing carbapenem resistant Acinetobacter baumannii isolates from hospital environment.}, journal = {Microbial pathogenesis}, volume = {99}, number = {}, pages = {204-208}, doi = {10.1016/j.micpath.2016.08.034}, pmid = {27569533}, issn = {1096-1208}, mesh = {Acinetobacter baumannii/*classification/enzymology/*genetics/isolation & purification ; Biofilms/growth & development ; Cluster Analysis ; DNA Gyrase/genetics ; Electrophoresis, Gel, Pulsed-Field ; *Environmental Microbiology ; *Genetic Variation ; *Genotype ; Hospitals ; Iran/epidemiology ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Molecular Typing ; Multiplex Polymerase Chain Reaction ; beta-Lactam Resistance ; beta-Lactamases/*analysis/genetics ; }, abstract = {Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients and it can survive for long periods in hospital settings, particularly on inanimate surfaces. The environment occupied by these resistant and resilient isolates may act as a reservoir for cross-colonization and outbreaks. Here, we aimed to determine the distribution of CRAB in the hospital environment and to characterize their clonal relatedness, susceptibility profile, carriage of blaOXA genes, and biofilm formation. A total of 1080 samples were collected from various environmental surfaces and equipment of two referral hospitals in Tehran, Iran. The A. baumannii isolates were subjected to gyrB multiplex PCR, antibiotic susceptibility testing, biofilm formation assay, pulsed field gel electrophoresis (PFGE), and multiplex PCR for blaOXA-58, blaOXA-24, and blaOXA-23 genes. Eighteen Acinetobacter spp. were isolated; 8 were identified as A. baumannii and 10 as A. lwoffii. Five of A. baumannii isolates were CRAB and exhibited the multidrug-resistant (MDR) phenotype as well. All CRAB isolates produced biofilm, albeit with different levels. Four of CRAB isolates harbored the blaOXA-23. The CRAB isolates were clustered into 3 distinct pulsotypes (PTs). The CRAB isolates belonging to PT1 were detected in two geographically distinct hospitals whereas those belonging to PT3 were found in two different units of same hospital. This study revealed the presence of clonally related OXA-23-producing CRAB in high risk units of referral hospitals as inter- or intra-hospital dissemination. The distribution of multiresistant A. baumannii on several surfaces and areas may increase the risk of transmission of resistant isolates to vulnerable patients.}, } @article {pmid27568380, year = {2016}, author = {Kumar, A and Ting, YP}, title = {Streptomycin favors biofilm formation by altering cell surface properties.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {20}, pages = {8843-8853}, doi = {10.1007/s00253-016-7793-0}, pmid = {27568380}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/*metabolism ; Bacterial Adhesion/drug effects ; Bacterial Proteins/analysis ; Biofilms/*growth & development ; Gene Expression Profiling ; Membrane Proteins/analysis ; Protein Synthesis Inhibitors/*metabolism ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; Streptomycin/*metabolism ; Surface Properties/*drug effects ; }, abstract = {Studies have shown that external stress induces biofilm formation, but the underlying details are not clearly understood. This study investigates the changes in cell surface properties leading to increase in biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa in the presence of streptomycin. Bacterial attachment in the presence and absence of streptomycin was quantified by fluorescence spectroscopy. In addition, cell surface charge and contact angle were measured and the free energy barrier for attachment was modeled using extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) theory. Peptides from bacterial cell surface were shaved by protease treatment and identified with ultra-performance liquid chromatography (UPLC)-QTOF and a homology search program SPIDER. Biofilm formation increased significantly in the presence of streptomycin (10 mg/L) in the culture. Bacterial cell surface charge reduced, and hydrophobicity increased leading to a net decrease in the free energy barrier for attachment. Extracellular matrix-binding protein was positively regulated in S. aureus under stress, indicating stronger interaction between bacterial cells and solid surface. In addition, several other proteins including biofilm regulatory proteins, multidrug efflux pumps, transporters, signaling proteins, and virulence factors were differentially expressed on bacterial cell surface, which is indicative of a strong stress response by bacteria to streptomycin treatment.}, } @article {pmid27568136, year = {2016}, author = {Elgharably, H and Hussain, ST and Shrestha, NK and Blackstone, EH and Pettersson, GB}, title = {Current Hypotheses in Cardiac Surgery: Biofilm in Infective Endocarditis.}, journal = {Seminars in thoracic and cardiovascular surgery}, volume = {28}, number = {1}, pages = {56-59}, doi = {10.1053/j.semtcvs.2015.12.005}, pmid = {27568136}, issn = {1532-9488}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacteria/classification/drug effects/*growth & development/pathogenicity ; Biofilms/drug effects/*growth & development ; Cardiac Surgical Procedures ; Drug Resistance, Bacterial ; Endocarditis, Bacterial/diagnosis/*microbiology/therapy ; Heart Valves/drug effects/*microbiology/surgery ; Humans ; }, abstract = {Despite recent advances in diagnostics and treatments, infective endocarditis is still associated with substantial morbidity and mortality. Even prolonged courses of broad-spectrum antimicrobials often fail to eradicate the infection, making surgical intervention necessary in many cases. In this review, we present recent advances in molecular microbiology techniques that have uncovered a plausible explanation for this resistance to treatment: the recently discovered social behavior of some microbes, in which colonies form a nearly impenetrable barrier around themselves called a biofilm. These biofilm structures isolate the colony from the body׳s immune response and antimicrobial drugs. We also present current thinking about possible ways biofilms can be destroyed.}, } @article {pmid27567965, year = {2016}, author = {Zhang, X and Chen, X and Zhang, C and Wen, H and Guo, W and Ngo, HH}, title = {Effect of filling fraction on the performance of sponge-based moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {219}, number = {}, pages = {762-767}, doi = {10.1016/j.biortech.2016.08.031}, pmid = {27567965}, issn = {1873-2976}, mesh = {Ammonia/metabolism ; Animals ; Biofilms ; Biomass ; *Bioreactors/microbiology ; Carbon/metabolism ; Denitrification ; Equipment Design ; Nitrification ; Nitrogen/isolation & purification/metabolism ; Polyurethanes ; Waste Disposal, Fluid/*instrumentation/methods ; Wastewater/chemistry ; }, abstract = {Cubic-shaped polyurethane sponges (15×15×15mm) in the form of biofilm carriers were used in a moving bed biofilm reactor (MBBR) for treating synthetic domestic wastewater. Results indicated there was no significant difference in total organic carbon (TOC) and ammonia (NH4(+)-N) removal at different filling fractions. Three reactors exhibited high removal efficiencies of over 93% TOC and 95% NH4(+)-N on average at an HRT of 12h and aeration flow of 0.09m(3)/h. However, total nitrogen (TN) removal and simultaneous nitrification and denitrification (SND) increased with increasing the filling fraction. TN removal averaged at 77.2, 85.5% and 86.7% in 10%, 20% and 30% filling fraction reactor, respectively. Correspondingly, SND were 85.5±8.7%, 91.3±9.4% and 93.3±10.2%. Moreover, it was observed that sponge carriers in the 20% filling fraction reactor achieved the maximum biomass amount per gram sponge, followed by the 10% and 30% filling fraction reactors.}, } @article {pmid27566515, year = {2016}, author = {Li, C and Wang, S and Du, X and Cheng, X and Fu, M and Hou, N and Li, D}, title = {Immobilization of iron- and manganese-oxidizing bacteria with a biofilm-forming bacterium for the effective removal of iron and manganese from groundwater.}, journal = {Bioresource technology}, volume = {220}, number = {}, pages = {76-84}, doi = {10.1016/j.biortech.2016.08.020}, pmid = {27566515}, issn = {1873-2976}, mesh = {Bacteria/*metabolism ; Biofilms ; Groundwater/chemistry/*microbiology ; Iron/isolation & purification/*metabolism ; Manganese/isolation & purification/*metabolism ; Sewage ; *Water Microbiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {In this study, three bacteria with high Fe- and Mn-oxidizing capabilities were isolated from groundwater well sludge and identified as Acinetobacter sp., Bacillus megaterium and Sphingobacterium sp. The maximum removal ratios of Fe and Mn (99.75% and 96.69%) were obtained by an optimal combination of the bacteria at a temperature of 20.15°C, pH 7.09 and an inoculum size of 2.08%. Four lab-scale biofilters were tested in parallel for the removal of iron and manganese ions from groundwater. The results indicated that the Fe/Mn removal ratios of biofilter R4, which was inoculated with iron- and manganese-oxidizing bacteria and a biofilm-forming bacterium, were approximately 95% for each metal during continuous operation and were better than the other biofilters. This study demonstrated that the biofilm-forming bacterium could promote the immobilization of the iron- and manganese-oxidizing bacteria on the biofilters and enhance the removal efficiency of iron and manganese ions from groundwater.}, } @article {pmid27565622, year = {2016}, author = {Yu, S and Wei, Q and Zhao, T and Guo, Y and Ma, LZ}, title = {A Survival Strategy for Pseudomonas aeruginosa That Uses Exopolysaccharides To Sequester and Store Iron To Stimulate Psl-Dependent Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {21}, pages = {6403-6413}, pmid = {27565622}, issn = {1098-5336}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects/*growth & development ; Cystic Fibrosis/microbiology/therapy ; Gene Expression Regulation, Bacterial ; Glycolipids/biosynthesis/metabolism ; Humans ; Iron/*metabolism/pharmacology ; Iron Chelating Agents/therapeutic use ; Mutation ; Polysaccharides, Bacterial/*metabolism ; Pseudomonas aeruginosa/drug effects/*physiology ; }, abstract = {UNLABELLED: Exopolysaccharide Psl is a critical biofilm matrix component in Pseudomonas aeruginosa, which forms a fiber-like matrix to enmesh bacterial communities. Iron is important for P. aeruginosa biofilm development, yet it is not clearly understood how iron contributes to biofilm development. Here, we showed that iron promoted biofilm formation via elevating Psl production in P. aeruginosa The high level of iron stimulated the synthesis of Psl by reducing rhamnolipid biosynthesis and inhibiting the expression of AmrZ, a repressor of psl genes. Iron-stimulated Psl biosynthesis and biofilm formation held true in mucoid P. aeruginosa strains. Subsequent experiments indicated that iron bound with Psl in vitro and in biofilms, which suggested that Psl fibers functioned as an iron storage channel in P. aeruginosa biofilms. Moreover, among three matrix exopolysaccharides of P. aeruginosa, Psl is the only exopolysaccharide that can bind with both ferrous and ferric ion, yet with higher affinity for ferrous iron. Our data suggest a survival strategy of P. aeruginosa that uses exopolysaccharide to sequester and store iron to stimulate Psl-dependent biofilm formation.

IMPORTANCE: Pseudomonas aeruginosa is an environmental microorganism which is also an opportunistic pathogen that can cause severe infections in immunocompromised individuals. It is the predominant airway pathogen causing morbidity and mortality in individuals affected by the genetic disease cystic fibrosis (CF). Increased airway iron and biofilm formation have been proposed to be the potential factors involved in the persistence of P. aeruginosa in CF patients. Here, we showed that a high level of iron enhanced the production of the key biofilm matrix exopolysaccharide Psl to stimulate Psl-dependent biofilm formation. Our results not only make the link between biofilm formation and iron concentration in CF, but also could guide the administration or use of iron chelators to interfere with biofilm formation in P. aeruginosa in CF patients. Furthermore, our data also imply a survival strategy of P. aeruginosa under high-iron environmental conditions.}, } @article {pmid27565555, year = {2016}, author = {Yang, Z and Liu, Y and Ahn, J and Qiao, Z and Endres, JL and Gautam, N and Huang, Y and Li, J and Zheng, J and Alnouti, Y and Bayles, KW and Li, R}, title = {Novel fluorinated pyrrolomycins as potent anti-staphylococcal biofilm agents: Design, synthesis, pharmacokinetics and antibacterial activities.}, journal = {European journal of medicinal chemistry}, volume = {124}, number = {}, pages = {129-137}, doi = {10.1016/j.ejmech.2016.08.017}, pmid = {27565555}, issn = {1768-3254}, support = {P30 GM103509/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/chemical synthesis/pharmacokinetics/pharmacology/toxicity ; Biofilms/*drug effects ; Chemistry Techniques, Synthetic ; *Drug Design ; *Halogenation ; HeLa Cells ; Humans ; Pyrroles/*chemical synthesis/pharmacokinetics/*pharmacology/toxicity ; Staphylococcus aureus/*drug effects/*physiology ; }, abstract = {Staphylococcus aureus (SA) is a major cause of hospital- and community-associated bacterial infections in the U.S. and around the world. These infections have become increasingly difficult to treat due to the propensity to develop antibiotic resistance and form biofilm. To date, no antibiofilm agents are available for clinical use. To add to the repertoire of antibiotics for clinical use and to provide novel agents for combating both SA and biofilm infections, we previously reported marinopyrroles as potent anti-SA agents. In this study, we used fragment-based and bioisostere approaches to design and synthesize a series of novel fluorinated pyrrolomycins for the first time, performed analyses of their physicochemical and drug-like properties, and investigated structure activity relationships and pharmacokinetics. These promising fluorinated pyrrolomycins demonstrate potent antibacterial activity against SA with favorable drug-like properties and pharmacokinetic profiles. Importantly, these compounds kill staphylococcal biofilm-associated cells with a lack of mammalian cell cytotoxicity and no occurrence of bacterial resistance. Our novel fluorinated pyrrolomycin 4 has a clogP value of 4.1, an MIC of 73 ng/mL, MBC of 4 μg/mL, kill staphylococcal-associated biofilm at 8 μg/mL, bioavailability of 35%, and the elimination half-life of 6.04 h and 6.75 h by intravenous and oral administration, respectively. This is the first report of comprehensive drug discovery studies on pyrrolomycin-based antibiotics.}, } @article {pmid27564400, year = {2017}, author = {Ring, HC and Bay, L and Nilsson, M and Kallenbach, K and Miller, IM and Saunte, DM and Bjarnsholt, T and Tolker-Nielsen, T and Jemec, GB}, title = {Bacterial biofilm in chronic lesions of hidradenitis suppurativa.}, journal = {The British journal of dermatology}, volume = {176}, number = {4}, pages = {993-1000}, doi = {10.1111/bjd.15007}, pmid = {27564400}, issn = {1365-2133}, mesh = {Adult ; *Biofilms ; Chronic Disease ; Female ; Hidradenitis Suppurativa/diagnostic imaging/*microbiology ; Humans ; Male ; Microscopy, Confocal ; Prospective Studies ; Staphylococcal Skin Infections/diagnostic imaging/*microbiology ; Staphylococcus aureus/isolation & purification ; }, abstract = {BACKGROUND: Chronic nonhealing or recurrent inflammatory lesions, reminiscent of infection but recalcitrant to antibiotic therapy, generally characterize biofilm-driven diseases. Chronic lesions of hidradenitis suppurativa (HS) exhibit several characteristics, which are compatible with well-known biofilm infections.

OBJECTIVES: To determine and quantify the potential presence of bacterial aggregates in chronic HS lesions.

METHODS: In 42 consecutive patients with HS suffering from chronic lesions, biopsies were obtained from lesional as well as from perilesional skin. Samples were investigated using peptide nucleic acid-fluorescence in situ hybridization in combination with confocal laser scanning microscopy. In addition, corresponding histopathological analysis on haematoxylin and eosin slides was performed.

RESULTS: Biofilms were seen in 67% of the samples of chronic lesions and in 75% of the perilesional samples. The mean diameter of aggregates in lesional skin was significantly greater than in perilesional skin (P = 0·01). Large biofilms (aggregates > 50 μm in diameter) were found in 42% of lesional samples and in only 5% of the perilesional samples (P = 0·009). The majority of the large biofilms were situated in sinus tracts (63%) or in the infundibulum (37%). The majority of the sinus tract samples (73%) contained active bacterial cells, which were associated with inflammation.

CONCLUSIONS: This study suggests that biofilm formation is associated with inflammation of chronic HS lesions. The aggregates most likely occur as a secondary event, possibly due to predisposing local anatomical changes such as sinus tracts (tunnels), keratinous detritus and dilated hair follicles.}, } @article {pmid27563242, year = {2016}, author = {Machado, MC and Webster, TJ}, title = {Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model.}, journal = {International journal of nanomedicine}, volume = {11}, number = {}, pages = {3825-3831}, pmid = {27563242}, issn = {1178-2013}, mesh = {Biofilms/*growth & development ; Humans ; Hydrodynamics ; *Intubation, Intratracheal ; *Models, Biological ; Nanoparticles/*chemistry ; Pseudomonas aeruginosa/*physiology ; Stress, Mechanical ; Trachea/*microbiology ; }, abstract = {Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP.}, } @article {pmid27562531, year = {2016}, author = {Lai, CY and Wen, LL and Shi, LD and Zhao, KK and Wang, YQ and Yang, X and Rittmann, BE and Zhou, C and Tang, Y and Zheng, P and Zhao, HP}, title = {Selenate and Nitrate Bioreductions Using Methane as the Electron Donor in a Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {50}, number = {18}, pages = {10179-10186}, doi = {10.1021/acs.est.6b02807}, pmid = {27562531}, issn = {1520-5851}, mesh = {*Biofilms ; Bioreactors ; Methane/*metabolism ; Oxidation-Reduction ; Selenic Acid ; }, abstract = {Selenate (SeO4(2-)) bioreduction is possible with oxidation of a range of organic or inorganic electron donors, but it never has been reported with methane gas (CH4) as the electron donor. In this study, we achieved complete SeO4(2-) bioreduction in a membrane biofilm reactor (MBfR) using CH4 as the sole added electron donor. The introduction of nitrate (NO3(-)) slightly inhibited SeO4(2-) reduction, but the two oxyanions were simultaneously reduced, even when the supply rate of CH4 was limited. The main SeO4(2-)-reduction product was nanospherical Se(0), which was identified by scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM-EDS). Community analysis provided evidence for two mechanisms for SeO4(2-) bioreduction in the CH4-based MBfR: a single methanotrophic genus, such as Methylomonas, performed CH4 oxidation directly coupled to SeO4(2-) reduction, and a methanotroph oxidized CH4 to form organic metabolites that were electron donors for a synergistic SeO4(2-)-reducing bacterium.}, } @article {pmid27562460, year = {2016}, author = {Kosikowska, U and Rybojad, P and Stępień-Pyśniak, D and Żbikowska, A and Malm, A}, title = {Changes in the prevalence and biofilm formation of Haemophilus influenzae and Haemophilus parainfluenzae from the respiratory microbiota of patients with sarcoidosis.}, journal = {BMC infectious diseases}, volume = {16}, number = {1}, pages = {449}, pmid = {27562460}, issn = {1471-2334}, mesh = {Adult ; Aged ; *Biofilms ; Case-Control Studies ; Female ; Haemophilus Infections/*complications/diagnosis/epidemiology ; Haemophilus influenzae/isolation & purification/*physiology ; Haemophilus parainfluenzae/isolation & purification/*physiology ; Humans ; Male ; Microbiota/physiology ; Middle Aged ; Nasopharynx/*microbiology ; Prevalence ; Sarcoidosis/*microbiology ; Sputum/*microbiology ; }, abstract = {BACKGROUND: Healthy condition and chronic diseases may be associated with microbiota composition and its properties. The prevalence of respiratory haemophili with respect to their phenotypes including the ability to biofilm formation in patients with sarcoidosis was assayed.

METHODS: Nasopharynx and sputum specimens were taken in 31 patients with sarcoidosis (average age 42.6 ± 13), and nasopharynx specimens were taken in 37 healthy people (average age 44.6 ± 11.6). Haemophili were identified by API-NH microtest and by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system. Biofilm was visualised by crystal violet staining and confocal scanning laser microscopy (CSLM). The statistical analysis was performed with Statgraphics Plus for Windows.

RESULTS: In total, 30/31 patients with sarcoidosis and 31/37 healthy people were colonized by Haemophilus influenzae (6/30 vs. 1/31) and Haemophilus parainfluenzae (28/30 vs. 31/31) in the nasopharynx. The overall number of nasopharyngeal haemophili isolates was 59 in patients with sarcoidosis and 67 in healthy volunteers (H. influenzae 6/59 vs. 1/67, P = 0.05; H. parainfluenzae 47/59 vs. 65/67, P = 0.0032). Moreover, the decreased number of H. parainfluenzae biofilm-producing isolates was shown in nasopharyngeal samples in patients with sarcoidosis as compared to healthy people (19/31 vs. 57/65, P = 0.006), especially with respect to isolates classified as strong and very strong biofilm-producers (8/31 vs. 39/65, P = 0.002).

CONCLUSIONS: The obtained data suggest that the qualitative and quantitative changes within the respiratory microbiota concerning the overall prevalence of H. influenzae together with the decreased number of H. parainfluenzae strains and the decreased rate of H. parainfluenzae biofilm-producing isolates as compared to healthy people may be associated with sarcoidosis.}, } @article {pmid27561323, year = {2016}, author = {Toninelli, AE and Wang, J and Liu, M and Wu, H and Liu, T}, title = {Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32305}, pmid = {27561323}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; *Biomass ; *Lighting ; Scenedesmus/*physiology ; }, abstract = {This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m(-2) d(-1) biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase.}, } @article {pmid27558743, year = {2016}, author = {Parnasa, R and Nagar, E and Sendersky, E and Reich, Z and Simkovsky, R and Golden, S and Schwarz, R}, title = {Small secreted proteins enable biofilm development in the cyanobacterium Synechococcus elongatus.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32209}, pmid = {27558743}, issn = {2045-2322}, mesh = {Amino Acid Motifs ; Bacterial Proteins/chemistry/genetics/*metabolism ; Biofilms/*growth & development ; Cysteine Proteases/genetics/metabolism ; Gene Expression Regulation, Bacterial ; Glycine ; Mutation ; Synechococcus/genetics/*physiology ; }, abstract = {Small proteins characterized by a double-glycine (GG) secretion motif, typical of secreted bacterial antibiotics, are encoded by the genomes of diverse cyanobacteria, but their functions have not been investigated to date. Using a biofilm-forming mutant of Synechococcus elongatus PCC 7942 and a mutational approach, we demonstrate the involvement of four small secreted proteins and their GG-secretion motifs in biofilm development. These proteins are denoted EbfG1-4 (enable biofilm formation with a GG-motif). Furthermore, the conserved cysteine of the peptidase domain of the Synpcc7942_1133 gene product (dubbed PteB for peptidase transporter essential for biofilm) is crucial for biofilm development and is required for efficient secretion of the GG-motif containing proteins. Transcriptional profiling of ebfG1-4 indicated elevated transcript levels in the biofilm-forming mutant compared to wild type (WT). However, these transcripts decreased, acutely but transiently, when the mutant was cultured in extracellular fluids from a WT culture, and biofilm formation was inhibited. We propose that WT cells secrete inhibitor(s) that suppress transcription of ebfG1-4, whereas secretion of the inhibitor(s) is impaired in the biofilm-forming mutant, leading to synthesis and secretion of EbfG1-4 and supporting the formation of biofilms.}, } @article {pmid27558435, year = {2016}, author = {Chen, G and Lin, H and Chen, X}, title = {Spatial Pattern of Copper Phosphate Precipitation Involves in Copper Accumulation and Resistance of Unsaturated Pseudomonas putida CZ1 Biofilm.}, journal = {Journal of microbiology and biotechnology}, volume = {26}, number = {12}, pages = {2116-2126}, doi = {10.4014/jmb.1605.05075}, pmid = {27558435}, issn = {1738-8872}, mesh = {*Biofilms ; Chemical Precipitation ; Copper/chemistry/*metabolism ; Microscopy, Electron, Transmission ; Phosphates/chemistry/*metabolism ; Pseudomonas putida/chemistry/genetics/*physiology/ultrastructure ; }, abstract = {Bacterial biofilms are spatially structured communities that contain bacterial cells with a wide range of physiological states. The spatial distribution and speciation of copper in unsaturated Pseudomonas putida CZ1 biofilms that accumulated 147.0 mg copper per g dry weight were determined by transmission electron microscopy coupled with energy dispersive X-ray analysis, and micro-X-ray fluorescence microscopy coupled with micro-X-ray absorption near edge structure (micro-XANES) analysis. It was found that copper was mainly precipitated in a 75 μm thick layer as copper phosphate in the middle of the biofilm, while there were two living cell layers in the air-biofilm and biofilm-medium interfaces, respectively, distinguished from the copper precipitation layer by two interfaces. The X-ray absorption fine structure analysis of biofilm revealed that species resembling Cu3(PO4)2 predominated in biofilm, followed by Cu-Citrate- and Cu-Glutathione-like species. Further analysis by micro-XANES revealed that 94.4% of copper were Cu3(PO4)2-like species in the layer next to the air interface, whereas the copper species of the layer next to the medium interface were composed by 75.4% Cu3(PO4)2, 10.9% Cu-Citrate-like species, and 11.2% Cu-Glutathione-like species. Thereby, it was suggested that copper was initially acquired by cells in the biofilm-air interface as a citrate complex, and then transported out and bound by out membranes of cells, released from the copper-bound membranes, and finally precipitated with phosphate in the extracellular matrix of the biofilm. These results revealed a clear spatial pattern of copper precipitation in unsaturated biofilm, which was responsible for the high copper tolerance and accumulation of the biofilm.}, } @article {pmid27558354, year = {2017}, author = {Mishra, SK and Teotia, AK and Kumar, A and Kannan, S}, title = {Mechanically tuned nanocomposite coating on titanium metal with integrated properties of biofilm inhibition, cell proliferation, and sustained drug delivery.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {13}, number = {1}, pages = {23-35}, doi = {10.1016/j.nano.2016.08.010}, pmid = {27558354}, issn = {1549-9642}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cell Line ; Cell Proliferation ; Coated Materials, Biocompatible/*pharmacology ; *Drug Delivery Systems ; Drug Liberation ; Humans ; Metal Nanoparticles/chemistry ; Microbial Sensitivity Tests ; Nanocomposites/*chemistry ; Naproxen/pharmacology ; Osteoblasts/cytology/drug effects ; Silver/*pharmacology ; Titanium/*chemistry ; }, abstract = {The clinical success of coated implants in executing biological functions inclusive of sustainable drug release and long term antibacterial activity without antibiotics is critical. To this aim, a nanohybrid of silver nanoparticles (AgNPs) cored in polyvinyl alcohol nanocapsules (Ag-PVA NCs) embedded in chitosan (CS) matrix loaded with anti-inflammatory drug naproxen was prepared. The synthesized nanohybrids that were subjected to coatings on (3-aminopropyl)triethoxysilane (APTES) treated titanium (Ti) metal exhibited dual role of excellent inhibition on biofilm formation and sustained drug release. These dual characteristics are achieved mainly based on intrinsic antibacterial property of AgNPs and differential entrapment of drug in PVA polymeric shell of AgNPs and CS matrix. The coatings also demonstrated enhanced mechanical properties with increasing inorganic filler and stress shielding on Ti metal. The biocompatibility tests involving adhesion, proliferation and differentiation of osteoblast cells demonstrated the efficacy of Ag-PVA NCs embedded in CS matrix as a suitable coating material for orthopedic applications.}, } @article {pmid27558353, year = {2017}, author = {Lin, MH and Hung, CF and Aljuffali, IA and Sung, CT and Huang, CT and Fang, JY}, title = {Cationic amphiphile in phospholipid bilayer or oil-water interface of nanocarriers affects planktonic and biofilm bacteria killing.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {13}, number = {2}, pages = {353-361}, doi = {10.1016/j.nano.2016.08.011}, pmid = {27558353}, issn = {1549-9642}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Mice ; Microbial Sensitivity Tests ; *Nanostructures ; Plankton ; Staphylococcus aureus ; }, abstract = {A cationic amphiphile, soyaethyl morpholinium ethosulfate (SME), immobilized in liposomes or nanoemulsions, was prepared in an attempt to compare the antibacterial activity between SME intercalated in the phospholipid bilayer and oil-water interface. Before antibacterial assessment, the size of the liposomes and nanoemulsions was respectively recorded as 75 and 214 nm. The data of minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) and live/dead cell count demonstrated a superior antimicrobial activity of nanoemulsions compared to liposomes against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Staphylococcus epidermidis. Nanoemulsion incubation reduced biofilm thickness by 2.4-fold, whereas liposomes showed a 1.6-fold decrease in thickness. SME insertion in the oil-water phase was found to induce bacterial membrane disruption. SME nanosystems were nontoxic to keratinocytes. In vivo topical application of the cationic nanosystems reduced skin infection, MRSA load, and inflammation in mice. The deteriorated skin barrier function evoked by MRSA was recovered by nanoemulsion treatment.}, } @article {pmid27558010, year = {2016}, author = {Hu, Y and He, L and Tao, X and Meng, F and Zhang, J}, title = {Biofilm may not be Necessary for the Epidemic Spread of Acinetobacter baumannii.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32066}, pmid = {27558010}, issn = {2045-2322}, mesh = {Acinetobacter Infections/*epidemiology/microbiology ; Acinetobacter baumannii/classification/drug effects/*pathogenicity/*physiology ; Bacterial Typing Techniques ; Biofilms/*growth & development ; Drug Resistance, Bacterial/drug effects ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; }, abstract = {Biofilm is recognized as a contributing factor to the capacity of Acinetobacter baumannii to persist and prosper in medical settings, but it is still unknown whether biofilms contribute to the spread of A. baumannii. In this study, the biofilm formation of 114 clinical A. baumannii isolates and 32 non-baumannii Acinetobacter isolates was investigated using a microtiter plate assay. The clonal relationships among A. baumannii isolates were assessed using pulsed-field gel electrophoresis and multilocus sequence typing, and one major outbreak clone and 5 other epidemic clones were identified. Compared with the epidemic or outbreak A. baumannii isolates, the sporadic isolates had significantly higher biofilm formation, but no significant difference was observed between the sporadic A. baumannii isolates and the non-baumannii Acinetobacter isolates, suggesting that biofilm is not important for the epidemic spread of A. baumannii. Of the multidrug-resistant (MDR) A. baumannii isolates in this study, 95.7% were assigned to international clone 2 (IC2) and showed significantly lower biofilm formations than the other isolates, suggesting that biofilm did not contribute to the high success of IC2. These findings have increased our understanding of the potential relationship between biofilm formation and the epidemic capacity of A. baumannii.}, } @article {pmid27555592, year = {2016}, author = {Yan, J and Sharo, AG and Stone, HA and Wingreen, NS and Bassler, BL}, title = {Vibrio cholerae biofilm growth program and architecture revealed by single-cell live imaging.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {36}, pages = {E5337-43}, pmid = {27555592}, issn = {1091-6490}, support = {R01 GM065859/GM/NIGMS NIH HHS/United States ; R37 GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion/genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cell Proliferation/genetics ; Humans ; Single-Cell Analysis/*methods ; Vibrio cholerae/genetics/growth & development/pathogenicity/*ultrastructure ; }, abstract = {Biofilms are surface-associated bacterial communities that are crucial in nature and during infection. Despite extensive work to identify biofilm components and to discover how they are regulated, little is known about biofilm structure at the level of individual cells. Here, we use state-of-the-art microscopy techniques to enable live single-cell resolution imaging of a Vibrio cholerae biofilm as it develops from one single founder cell to a mature biofilm of 10,000 cells, and to discover the forces underpinning the architectural evolution. Mutagenesis, matrix labeling, and simulations demonstrate that surface adhesion-mediated compression causes V. cholerae biofilms to transition from a 2D branched morphology to a dense, ordered 3D cluster. We discover that directional proliferation of rod-shaped bacteria plays a dominant role in shaping the biofilm architecture in V. cholerae biofilms, and this growth pattern is controlled by a single gene, rbmA Competition analyses reveal that the dense growth mode has the advantage of providing the biofilm with superior mechanical properties. Our single-cell technology can broadly link genes to biofilm fine structure and provides a route to assessing cell-to-cell heterogeneity in response to external stimuli.}, } @article {pmid27554277, year = {2016}, author = {Inbakandan, D and Kumar, C and Bavanilatha, M and Ravindra, DN and Kirubagaran, R and Khan, SA}, title = {Ultrasonic-assisted green synthesis of flower like silver nanocolloids using marine sponge extract and its effect on oral biofilm bacteria and oral cancer cell lines.}, journal = {Microbial pathogenesis}, volume = {99}, number = {}, pages = {135-141}, doi = {10.1016/j.micpath.2016.08.018}, pmid = {27554277}, issn = {1096-1208}, mesh = {Animals ; Anti-Infective Agents/metabolism/*pharmacology ; Antineoplastic Agents/metabolism/*pharmacology ; Aquatic Organisms/chemistry ; Bacteria/drug effects ; Biofilms/*drug effects ; Cell Extracts/isolation & purification ; Cell Line, Tumor ; Cell Proliferation/*drug effects ; Microscopy, Electron, Transmission ; Nanostructures/*chemistry/ultrastructure ; Porifera/*chemistry ; Silver/*metabolism/pharmacology ; Spectroscopy, Fourier Transform Infrared ; Spectrum Analysis ; Ultrasonic Waves ; X-Ray Diffraction ; }, abstract = {The knowhow followed for synthesis, characterization and application of nanomaterials has become an important branch of nanoscience. The use of marine sponges for the synthesis of metal nanoparticles is still in the budding level of current nanobiotechnology. This paper reports a single step one pot biosynthesis utilizing marine sponge (Haliclona exigua) extract as a reducing agent by means of a conventional ultrasonic bath on the formation and growth of flower like silver nanocolloids. These silver nanocolloids were characterized through UV visible spectroscopy, High Resolution Transmission Electron Microscope, Fourier Transform Infrared spectroscopy and X-ray Diffractometer. Further, antibacterial activity and antiproliferative activity were done against oral biofilm bacteria and oral cancer cell lines for the biosynthesized flower like silver nanocolloids. Water soluble organic amines were responsible for the syntheses of nanomaterials which have a size range from 100 to 120 nm. An average size of 9.1 mm zone of inhibition was recorded with 10.0 μg of silver nanocolloids against oral biofilm bacteria. The estimated half maximal inhibitory concentration value for flower like silver nanocolloids was 0.6 μg/ml for oral cancer cell lines.}, } @article {pmid27554275, year = {2016}, author = {Feraco, D and Blaha, M and Khan, S and Green, JM and Plotkin, BJ}, title = {Host environmental signals and effects on biofilm formation.}, journal = {Microbial pathogenesis}, volume = {99}, number = {}, pages = {253-263}, doi = {10.1016/j.micpath.2016.08.015}, pmid = {27554275}, issn = {1096-1208}, mesh = {Animals ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Fungi/*physiology ; *Host-Pathogen Interactions ; Humans ; Quorum Sensing/drug effects ; }, abstract = {Biofilm matrix formation is a phenotype linked to the ability to survive a hostile host environment that includes the presence of antimicrobial peptides and serum factors. Multiple hormones and other host derived factors have been shown to function as exogenous quorum signaling compound homologs that inform microbes of their in situ presence, thus triggering a shift from a planktonic to the sessile biofilm phenotype. The focus of this review is to describe the impact various host-derived factors have on the initial steps required for biofilm formation, i.e., adherence to host surfaces and multiplication in the host.}, } @article {pmid27553840, year = {2016}, author = {Sarkar, P and Acharyya, S and Banerjee, A and Patra, A and Thankamani, K and Koley, H and Bag, PK}, title = {Intracellular, biofilm-inhibitory and membrane-damaging activities of nimbolide isolated from Azadirachta indica A. Juss (Meliaceae) against meticillin-resistant Staphylococcus aureus.}, journal = {Journal of medical microbiology}, volume = {65}, number = {10}, pages = {1205-1214}, doi = {10.1099/jmm.0.000343}, pmid = {27553840}, issn = {1473-5644}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Azadirachta/*chemistry ; Biofilms/*drug effects ; Cell Membrane/*drug effects ; Chlorocebus aethiops ; Humans ; Limonins/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Plant Extracts/*pharmacology ; Staphylococcal Infections/*microbiology ; Vero Cells ; }, abstract = {Staphylococcus aureus is a leading aetiologic agent of nosocomial- and community-acquired infectious diseases worldwide. The public health concern regarding staphylococcal infections is inflated by the increasing occurrence of multidrug-resistant strains, e.g. multidrug- and meticillin-resistant S.aureus (MDR MRSA). This study was designed to evaluate the intracellular killing, membrane-damaging and biofilm-inhibitory activities of nimbolide isolated from Azadirachta indica against MDR MRSA. In vitro antibacterial activity of nimbolide was determined by performing MIC, minimal bactericidal concentration (MBC) and time-kill kinetic studies. Bacterial membrane-damaging activity was determined by membrane perturbation and scanning electron microscopy (SEM) examination. Biofilm-inhibitory activities were determined by SEM. Cellular drug accumulation and assessments of intracellular activities were performed using Vero cell culture. SEM revealed that nimbolide caused significant membrane damage and lysis of the S. aureus cells. The biofilm structure was disrupted, and the biofilm formation was greatly reduced in the presence of nimbolide as examined by SEM. The level of accumulation of nimbolide in Vero cells incubated for 24 h is relatively higher than that of ciprofloxacin and nalidixic acid (Cc/Ce for nimbolide > ciprofloxacin and nalidixic acid). The viable number of intracellular S. aureus was decreased [reduction of ~2 log10 c.f.u. (mg Vero cell protein)-1] in a time-dependent manner in the presence of nimbolide (4× MBC) that was comparable to that of tetracycline and nalidixic acid. The significant intracellular, biofilm-inhibitory and bacterial membrane-damaging activities of nimbolide demonstrated here suggested that it has potential as an effective antibacterial agent for the treatment of severe infections caused by MDR MRSA.}, } @article {pmid27552718, year = {2016}, author = {Miao, L and Wang, S and Cao, T and Peng, Y and Zhang, M and Liu, Z}, title = {Advanced nitrogen removal from landfill leachate via Anammox system based on Sequencing Biofilm Batch Reactor (SBBR): Effective protection of biofilm.}, journal = {Bioresource technology}, volume = {220}, number = {}, pages = {8-16}, doi = {10.1016/j.biortech.2016.06.131}, pmid = {27552718}, issn = {1873-2976}, mesh = {Bacteria/genetics/metabolism ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification ; Equipment Design ; Flocculation ; Heterotrophic Processes ; Microbial Consortia/genetics/physiology ; Nitrogen/chemistry/*isolation & purification ; Waste Disposal, Fluid/*instrumentation/*methods ; Water Pollutants, Chemical/*chemistry/metabolism ; }, abstract = {High levels of organics negatively affect Anammox for treating landfill leachate. To enhance the ability of Anammox to survive against adverse environments, a lab-scale two-stage Anammox system using a Sequencing Biofilm Batch Reactor was applied to treat mature landfill leachate under 35°C. Over 107days, with influent total nitrogen (TN) and chemical oxygen demand (COD) concentrations of 3000±100 and 3000±100mg/L, effluent TN was below 20mg/L. For extracellular polymeric substance (EPS) of Anammox, slime-EPS and loosely-bound-EPS of floccules were both higher than biofilm, while tight-bound-EPS of biofilm was significantly higher, contributing to biofilm formation. Quantitative microbial analysis showed that as influent COD increased, Anammox gene ratios of biofilm increased from 1.34% to 13.28%; the gene ratios of floccule first increased, then decreased to 3.88%. This indicated that Anammox and heterotrophic bacteria could coexist because of the biofilm, leading to stable nitrogen removal performance, even when organics were present.}, } @article {pmid27551781, year = {2016}, author = {Piculell, M and Suarez, C and Li, C and Christensson, M and Persson, F and Wagner, M and Hermansson, M and Jönsson, K and Welander, T}, title = {The inhibitory effects of reject water on nitrifying populations grown at different biofilm thickness.}, journal = {Water research}, volume = {104}, number = {}, pages = {292-302}, doi = {10.1016/j.watres.2016.08.027}, pmid = {27551781}, issn = {1879-2448}, mesh = {Bacteria ; *Biofilms ; Bioreactors/*microbiology ; Nitrification ; Nitrites ; Water ; }, abstract = {Suppression of nitrite oxidizing bacteria (NOB) is of vital importance to achieve successful, energy efficient, mainstream anammox processes for wastewater treatment. In this study, biofilm carriers from a fully nitrifying MBBR system, fed with mainstream wastewater, were temporarily exposed to reject water from sludge dewatering, to evaluate this as a possible strategy to inhibit NOB and achieve nitrite production under realistic conditions. Two different carrier types were compared, in which biofilm thickness was maintained at approximately 400 and 50 μm, respectively, and reject treatment was tested at different exposure time and loading rates. Reject exposure almost always resulted in an increased nitrite production in the thinner biofilm, and overall, nitrifiers growing in the thin biofilm were more sensitive than those grown in the thicker biofilm. The effect from reject exposure remained in the systems for four days after returning to mainstream operation, with nitrite production gradually increasing for three days. Increased concentrations of free ammonia correlated with reject exposure and may be the cause of inhibition, although other factors cannot be excluded.}, } @article {pmid27551088, year = {2016}, author = {Schumacher, MA and Zeng, W}, title = {Structures of the activator of K. pneumonia biofilm formation, MrkH, indicates PilZ domains involved in c-di-GMP and DNA binding.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {36}, pages = {10067-10072}, pmid = {27551088}, issn = {1091-6490}, support = {R01 GM115547/GM/NIGMS NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Amino Acid Motifs ; Bacterial Proteins/*chemistry/genetics/metabolism ; Binding Sites ; Biofilms/*growth & development ; Cloning, Molecular ; Crystallography, X-Ray ; Cyclic GMP/*analogs & derivatives/chemistry/metabolism ; DNA, Bacterial/*chemistry/metabolism ; Gene Expression ; Gene Expression Regulation, Bacterial ; Klebsiella pneumoniae/*genetics/pathogenicity ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Folding ; Protein Interaction Domains and Motifs ; Recombinant Proteins/chemistry/genetics/metabolism ; Transcription Factors/*chemistry/genetics/metabolism ; }, abstract = {The pathogenesis of Klebsiella pneumonia is linked to the bacteria's ability to form biofilms. Mannose-resistant Klebsiella-like (Mrk) hemagglutinins are critical for K pneumonia biofilm development, and the expression of the genes encoding these proteins is activated by a 3',5'-cyclic diguanylic acid (c-di-GMP)-regulated transcription factor, MrkH. To gain insight into MrkH function, we performed structural and biochemical analyses. Data revealed MrkH to be a monomer with a two-domain architecture consisting of a PilZ C-domain connected to an N domain that unexpectedly also harbors a PilZ-like fold. Comparison of apo- and c-di-GMP-bound MrkH structures reveals a large 138° interdomain rotation that is induced by binding an intercalated c-di-GMP dimer. c-di-GMP interacts with PilZ C-domain motifs 1 and 2 (RxxxR and D/NxSxxG) and a newly described c-di-GMP-binding motif in the MrkH N domain. Strikingly, these c-di-GMP-binding motifs also stabilize an open state conformation in apo MrkH via contacts from the PilZ motif 1 to residues in the C-domain motif 2 and the c-di-GMP-binding N-domain motif. Use of the same regions in apo structure stabilization and c-di-GMP interaction allows distinction between the states. Indeed, domain reorientation by c-di-GMP complexation with MrkH, which leads to a highly compacted structure, suggests a mechanism by which the protein is activated to bind DNA. To our knowledge, MrkH represents the first instance of specific DNA binding mediated by PilZ domains. The MrkH structures also pave the way for the rational design of inhibitors that target K pneumonia biofilm formation.}, } @article {pmid27548153, year = {2016}, author = {Estevam-Alves, R and Ferreira, PH and Coatrini, AC and Oliveira, ON and Fontana, CR and Mendonca, CR}, title = {Femtosecond Laser Patterning of the Biopolymer Chitosan for Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {17}, number = {8}, pages = {}, pmid = {27548153}, issn = {1422-0067}, mesh = {Bacterial Adhesion/drug effects ; Biocompatible Materials/chemistry/pharmacology ; Biofilms/*drug effects ; Biopolymers/*chemistry/pharmacology ; Chitosan/*chemistry/pharmacology ; Hydrophobic and Hydrophilic Interactions ; Microscopy, Atomic Force ; Staphylococcus aureus/drug effects ; }, abstract = {Controlling microbial growth is crucial for many biomedical, pharmaceutical and food industry applications. In this paper, we used a femtosecond laser to microstructure the surface of chitosan, a biocompatible polymer that has been explored for applications ranging from antimicrobial action to drug delivery. The influence of energy density on the features produced on chitosan was investigated by optical and atomic force microscopies. An increase in the hydrophilic character of the chitosan surface was attained upon laser micromachining. Patterned chitosan films were used to observe Staphylococcus aureus (ATCC 25923) biofilm formation, revealing an increase in the biofilm formation in the structured regions. Our results indicate that fs-laser micromachining is an attractive option to pattern biocompatible surfaces, and to investigate basic aspects of the relationship between surface topography and bacterial adhesion.}, } @article {pmid27543817, year = {2016}, author = {Sivaranjani, M and Gowrishankar, S and Kamaladevi, A and Pandian, SK and Balamurugan, K and Ravi, AV}, title = {Morin inhibits biofilm production and reduces the virulence of Listeria monocytogenes - An in vitro and in vivo approach.}, journal = {International journal of food microbiology}, volume = {237}, number = {}, pages = {73-82}, doi = {10.1016/j.ijfoodmicro.2016.08.021}, pmid = {27543817}, issn = {1879-3460}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Caenorhabditis elegans ; Flavonoids/*pharmacology ; Humans ; Listeria monocytogenes/*drug effects/genetics/*pathogenicity/physiology ; Listeriosis/drug therapy/*microbiology ; Microbial Sensitivity Tests ; Virulence/drug effects ; }, abstract = {The current study explores the in vitro and in vivo antibiofilm efficacy of morin against a leading foodborne pathogen-Listeria monocytogenes (LM). Minimum inhibitory concentration (MIC) of morin against LM strains was found to be 100μg/ml. The non-antibacterial effect of morin at its sub-MICs (6.25, 12.5 and 25μg/ml) was determined through growth curve and XTT assay. Morin at its sub-MICs demonstrated a significant dose dependent inhibitory efficacy against LM biofilm formation which was also evidenced through light, confocal and scanning electron microscopic analyses. However, morin failed to disperse the mature biofilm of LM even at its MIC. Our data also revealed the anti-virulence efficacy of morin, as it significantly inhibited the production of hemolysin and motility of LM. Concentration-dependent susceptibility of morin treated LM cells to normal human serum was observed. In vivo studies revealed that morin extended the lifespan of LM infected Caenorhabditis elegans by about 85%. Furthermore, the non-toxic nature and in vivo anti-adherence efficacy of morin were also ascertained through C. elegans-LM infection model. Overall, the data of the current study identifies morin as a promising antibiofilm agent and its suitability to formulate protective strategies against biofilm associated infections caused by LM.}, } @article {pmid27543691, year = {2016}, author = {Steinmetz, HP and Rudnick-Glick, S and Natan, M and Banin, E and Margel, S}, title = {Graft polymerization of styryl bisphosphonate monomer onto polypropylene films for inhibition of biofilm formation.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {147}, number = {}, pages = {300-306}, doi = {10.1016/j.colsurfb.2016.08.007}, pmid = {27543691}, issn = {1873-4367}, mesh = {Bacteria/drug effects/*growth & development ; Biofilms/drug effects/*growth & development ; Bone Density Conservation Agents/chemistry/*pharmacology ; Diphosphonates/chemistry/*pharmacology ; Microscopy, Atomic Force ; Photoelectron Spectroscopy ; Polymerization ; Polymers/*chemistry ; Propylene Glycols/*chemistry ; Styrene/*chemistry ; Viscosity ; }, abstract = {There has been increased concern during the past few decades over the role bacterial biofilms play in causing a variety of health problems, especially since they exhibit a high degree of resistance to antibiotics and are able to survive in hostile environments. Biofilms consist of bacterial aggregates enveloped by a self-produced matrix attached to the surface. Ca(2+) ions promote the formation of biofilms, and enhance their stability, viscosity, and strength. Bisphosphonates exhibit a high affinity for Ca(2+) ions, and may inhibit the formation of biofilms by acting as sequestering agents for Ca(2+) ions. Although the antibacterial activity of bisphosphonates is well known, research into their anti-biofilm behavior is still in its early stages. In this study, we describe the synthesis of a new thin coating composed of poly(styryl bisphosphonate) grafted onto oxidized polypropylene films for anti-biofilm applications. This grafting process was performed by graft polymerization of styryl bisphosphonate vinylic monomer onto O2 plasma-treated polypropylene films. The surface modification of the polypropylene films was confirmed using surface measurements, including X-ray photoelectron spectroscopy, atomic force microscopy, and water contact angle goniometry. Significant inhibition of biofilm formation was achieved for both Gram-negative and Gram-positive bacteria.}, } @article {pmid27543131, year = {2016}, author = {González, AG and Fernández-Rojo, L and Leflaive, J and Pokrovsky, OS and Rols, JL}, title = {Response of three biofilm-forming benthic microorganisms to Ag nanoparticles and Ag[+]: the diatom Nitzschia palea, the green alga Uronema confervicolum and the cyanobacteria Leptolyngbya sp.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {21}, pages = {22136-22150}, pmid = {27543131}, issn = {1614-7499}, mesh = {Biofilms/*drug effects/growth & development ; Chlorophyta/*drug effects/physiology ; Cyanobacteria/*drug effects/physiology ; Diatoms/*drug effects/physiology ; Metal Nanoparticles/*toxicity ; Silver/*toxicity ; Time Factors ; Water Pollutants, Chemical/*toxicity ; }, abstract = {Although the industrial use of nanoparticles has increased over the past decade, the knowledge about their interaction with benthic phototrophic microorganisms in the environment is still limited. This study aims to characterize the toxic effect of ionic Ag[+] and Ag nanoparticles (citrate-coated silver nanoparticles, AgNPs) in a wide concentration range (from 1 to 1000 μg L[-1]) and duration of exposure (2, 5 and 14 days) on three biofilm-forming benthic microorganisms: diatom Nitzschia palea, green algae Uronema confervicolum and cyanobacteria Leptolyngbya sp. Ag[+] has a significant effect on the growth of all three species at low concentrations (1-10 μg L[-1]), whereas the inhibitory effect of AgNPs was only observed at 1000 μg L[-1] and solely after 2 days of exposure. The inhibitory effect of both Ag[+] and AgNPs decreased in the course of the experiments from 2 to 14 days, which can be explained by the progressive excretion of the exopolysaccharides and dissolved organic carbon by the microorganisms, thus allowing them to alleviate the toxic effects of aqueous silver. The lower impact of AgNPs on cells compared to Ag[+] can be explained in terms of availability, internalization, reactive oxygen species production, dissolved silver concentration and agglomeration of AgNPs. The duration of exposure to Ag[+] and AgNPs stress is a fundamental parameter controlling the bioaccumulation and detoxification in benthic phototrophic microorganisms.}, } @article {pmid27543126, year = {2016}, author = {Hou, J and You, G and Xu, Y and Wang, C and Wang, P and Miao, L and Ao, Y and Li, Y and Lv, B and Yang, Y}, title = {Impacts of CuO nanoparticles on nitrogen removal in sequencing batch biofilm reactors after short-term and long-term exposure and the functions of natural organic matter.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {21}, pages = {22116-22125}, pmid = {27543126}, issn = {1614-7499}, mesh = {Bacteria/metabolism ; *Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors ; Copper/*metabolism ; Humic Substances/analysis ; *Metal Nanoparticles ; Nitrogen/*metabolism ; Time Factors ; Waste Disposal, Fluid ; Wastewater/analysis ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The impacts of CuO nanoparticle (NP) exposure on total nitrogen (TN) removal in a sequencing batch biofilm reactor (SBBR) as well as the effects of natural organic matter (NOM) in wastewater were studied. Short-term exposure (8 h) to 1 and 50 mg/L CuO NPs induced negligible influence on the nitrogen removal efficiency, and biofilms could recover from the slight damage caused by the prolonged exposure (45 days) to 1 mg/L CuO NPs. On the other hand, long-term exposure to 50 mg/L CuO NPs notably decreased the nitrogen removal efficiencies to 47.74 and 59.04 % in the absence and presence of bovine serum albumin (BSA), much lower than those in the control (75.43 %), mainly as the suppressed denitrification process. Analysis of key enzyme activities showed that the activities of nitrite reductase and nitrate reductase were obviously reduced with 50 mg/L CuO NP exposure. Further studies revealed that the inhibited nitrite/nitrate reductase was related to the variations of microenvironment pH and decrease of nirS and nirK by microelectrode and fluorescent quantitative polymerase chain reaction (PCR) analysis. In addition, the presence of BSA mitigated the toxicity of CuO NPs due to the enhanced particle size and Cu[2+] release, electrostatic repulsion, and surface coating of CuO NPs, which indicated that lower inhibition effects of CuO NPs in NOM-rich wastewater is of importance when evaluating the environmental risk of NPs to wastewater treatment plants.}, } @article {pmid27542729, year = {2017}, author = {Doulgeraki, AI and Di Ciccio, P and Ianieri, A and Nychas, GE}, title = {Methicillin-resistant food-related Staphylococcus aureus: a review of current knowledge and biofilm formation for future studies and applications.}, journal = {Research in microbiology}, volume = {168}, number = {1}, pages = {1-15}, doi = {10.1016/j.resmic.2016.08.001}, pmid = {27542729}, issn = {1769-7123}, mesh = {Animals ; Biofilms/*growth & development ; *Food Microbiology ; Gene Expression Regulation, Bacterial ; Methicillin-Resistant Staphylococcus aureus/*isolation & purification/*physiology ; Quorum Sensing ; Staphylococcal Infections/microbiology/*veterinary ; }, abstract = {There is increasing concern about the public health impact of methicillin-resistant Staphylococcus aureus. Food and animal are vectors of transmission, but the contribution of a contaminated environment is not well characterized. With regard to this, staphylococcal biofilms serve as a virulence factor, allowing MRSA strains to adhere to surfaces and other materials used in the food industry. Methicillin resistance and biofilm-forming capacity may contribute to the success of S. aureus as a human pathogen in both health care and community settings and the food production chain. This review summarizes current knowledge about the significance of food- and animal-derived MRSA strains and provides data on attachment and biofilm formation of MRSA. In addition, the impact of quorum sensing on MRSA gene expression and biofilm formation is examined.}, } @article {pmid27541158, year = {2017}, author = {Taktek, S and St-Arnaud, M and Piché, Y and Fortin, JA and Antoun, H}, title = {Igneous phosphate rock solubilization by biofilm-forming mycorrhizobacteria and hyphobacteria associated with Rhizoglomus irregulare DAOM 197198.}, journal = {Mycorrhiza}, volume = {27}, number = {1}, pages = {13-22}, pmid = {27541158}, issn = {1432-1890}, mesh = {Biofilms/*growth & development ; Burkholderia/*physiology ; Glomeromycota/*physiology ; Hydrogen-Ion Concentration ; Mycorrhizae/*physiology ; Rahnella/*physiology ; Rhizobium/*physiology ; }, abstract = {Biofilm formation on abiotic and biotic surfaces was studied with two hyphobacteria, strongly attached to the surface of the arbuscular mycorrhizal fungus (AMF) Rhizoglomus irregulare (Ri) DAOM 197198 and two mycorrhizobacteria, loosely attached to the roots of different mycorrhizal plants. When the sparingly soluble igneous phosphate rock (PR) from Quebec, or when the chemical hydroxyapatite were used as sole phosphorus (P) source, hyphobacteria Rhizobium miluonense Rm3 and Burkholderia anthina Ba8 produced significantly more biofilms than mycorrhizobacteria Rahnella sp. Rs11 and Burkholderia phenazinium Bph12, as indicated by the crystal violet assay or by quantifying biofilm exopolysaccharides. As previously observed with planktonic bacteria, biofilms mobilized P by lowering the pH and releasing gluconic acid. The high efficiency of P mobilization by the hyphobacteria Ba8 was linked to the presence of more viable cells in its biofilm as revealed by the hydrolysis of fluorescein diacetate. Scanning electron microscopy micrographs showed a high adherence of the best P-solubilizer hyphobacteria Ba8 on the surface of Quebec PR. Hydroxyapatite porous structure did not allow a good adherence of Ba8. Ba8 formed an important biofilm on the hyphae of Ri DAOM 197198 with low reactive Quebec PR while no biofilm was observed with the high reactive hydroxyapatite. Results confirm the possible presence of specificity between the Ri DAOM 197198 and the hyphobacteria and suggest that the interaction would be regulated by the availability of P.}, } @article {pmid27540070, year = {2016}, author = {Xu, Y and Nagy, A and Yan, X and Haley, BJ and Kim, SW and Liu, NT and Nou, X}, title = {Genome Sequences of Ralstonia insidiosa Type Strain ATCC 49129 and Strain FC1138, a Strong Biofilm Producer Isolated from a Fresh-Cut Produce-Processing Plant.}, journal = {Genome announcements}, volume = {4}, number = {4}, pages = {}, pmid = {27540070}, issn = {2169-8287}, abstract = {Ralstonia insidiosa is an opportunistic pathogen and a strong biofilm producer. Here, we present the complete genome sequences of R. insidiosa FC1138 and ATCC 49129. Both strains have two circular chromosomes of approximately 3.9 and 1.9 Mb and a 50-kb plasmid. ATCC 49129 also possesses a megaplasmid of approximately 318 kb.}, } @article {pmid27539815, year = {2017}, author = {Pejin, B and Ciric, A and Dimitric Markovic, J and Glamoclija, J and Nikolic, M and Sokovic, M}, title = {An insight into anti-biofilm and anti-quorum sensing activities of the selected anthocyanidins: the case study of Pseudomonas aeruginosa PAO1.}, journal = {Natural product research}, volume = {31}, number = {10}, pages = {1177-1180}, doi = {10.1080/14786419.2016.1222386}, pmid = {27539815}, issn = {1478-6427}, mesh = {Anthocyanins/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects ; Pyocyanine/biosynthesis ; Quorum Sensing/*drug effects ; }, abstract = {Anti-biofilm activity of three anthocyanidins (pelargonidin, cyanidin and delphinidin) was evaluated for the first time at in vitro conditions. All the compounds reduced the formation of Pseudomonas aeruginosa PAO1 biofilm at low sub-MIC (0.125 MIC) with delphinidin (c 56.25 μg/mL) being the most active (43%). In comparison, ampicillin (c 93.75 μg/mL) and streptomycin (c 21.25 μg/mL) (used as positive controls) were considerably less effective at the same sub-MIC (8 and 12%, respectively). Furthermore, at 0.5 MIC (c 225 μg/mL) this anthocyanidin molecule partly reduced the bacterial protrusions. However, no any of the aforementioned compounds inhibited the production of pyocyanin by the bacterial strain P. aeruginosa PAO1. Taken all together, the delphinidin scaffold could be taken into consideration for the design of the novel and more effective anti-biofilm agents inspired by the anthocyanidins.}, } @article {pmid27539641, year = {2017}, author = {Jablonowski, L and Fricke, K and Matthes, R and Holtfreter, B and Schlüter, R and von Woedtke, T and Weltmann, KD and Kocher, T}, title = {Removal of naturally grown human biofilm with an atmospheric pressure plasma jet: An in-vitro study.}, journal = {Journal of biophotonics}, volume = {10}, number = {5}, pages = {718-726}, doi = {10.1002/jbio.201600166}, pmid = {27539641}, issn = {1864-0648}, mesh = {*Argon ; Atmospheric Pressure ; *Biofilms ; Humans ; Microscopy, Electron, Scanning ; Oxygen ; Tooth/*microbiology ; Toothbrushing/*instrumentation ; }, abstract = {The removal of biofilm is a prerequisite for a successful treatment of biofilm-associated diseases. In this study, we compared the feasibility of an atmospheric pressure plasma device with a sonic powered brush to remove naturally grown supragingival biofilm from extracted teeth. Twenty-four periodontally hopeless teeth were extracted. Argon jet plasma with an oxygen admixture of 1 vol% and a sonically driven brush were used to remove biofilm with application times of 60 s, 180 s and 300 s. The treatment efficiency was assessed with light microscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The highest biofilm removal rate was observed after an application time of 180 s/300 s with the sonic brush (80.4%/86.2%), plasma (75.5%/89.0%). These observations were confirmed by SEM. According to XPS analysis, plasma treatment decreased the amount of carbon and nitrogen, indicative of an extensive removal of proteins. Plasma treatment of naturally grown biofilm resulted in an effective cleaning of the tooth surface and was comparable to mechanical treatment. Treatment time had a significant influence on plaque reduction. These results showed that plasma could be a useful adjuvant treatment modality in cases where biofilm removal or reduction plays a decisive role, such as periodontitis and peri-implantitis. Plasma-treated biofilm on an extracted tooth.}, } @article {pmid27538256, year = {2016}, author = {Kreling, PF and Aida, KL and Massunari, L and Caiaffa, KS and Percinoto, C and Bedran, TB and Spolidorio, DM and Abuna, GF and Cilli, EM and Duque, C}, title = {Cytotoxicity and the effect of cationic peptide fragments against cariogenic bacteria under planktonic and biofilm conditions.}, journal = {Biofouling}, volume = {32}, number = {9}, pages = {995-1006}, doi = {10.1080/08927014.2016.1218850}, pmid = {27538256}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/*pharmacology/toxicity ; Antimicrobial Cationic Peptides/*pharmacology/toxicity ; Biofilms/*drug effects ; Cell Line ; Cell Survival/drug effects ; Chlorhexidine/pharmacology/toxicity ; Dental Caries/microbiology ; Humans ; Microbial Sensitivity Tests ; Peptide Fragments/*pharmacology/toxicity ; Plankton/*drug effects ; Streptococcus mutans/*drug effects/growth & development/physiology ; }, abstract = {This study evaluated the cytotoxicity and effect of fragments derived from three oral cationic peptides (CP): LL-37, D6-17 and D1-23 against cariogenic bacteria under planktonic and biofilm conditions. For cytotoxicity analysis, two epithelial cell lines were used. The minimum inhibitory concentration and the minimal bactericidal concentration were determined for the CP fragments and the control (chlorhexidine-CHX) against cariogenic bacteria. The fractional inhibitory concentration was obtained for the combinations of CP fragments on Streptococcus mutans. Biofilm assays were conducted with the best antimicrobial CP fragment against S. mutans. The results indicated that D6-17 was not cytotoxic. D1-23, LL-37 and CHX were not cytotoxic in low concentrations. D1-23 presented the best bactericidal activity against S. mutans, S. mitis and S. salivarius. Combinations of CP fragments did not show a synergic effect. D1-23 presented a higher activity against S. mutans biofilm than CHX. It was concluded that D1-23 showed a substantial effect against cariogenic bacteria and low cytotoxicity.}, } @article {pmid27537843, year = {2016}, author = {Petrova, MI and Imholz, NC and Verhoeven, TL and Balzarini, J and Van Damme, EJ and Schols, D and Vanderleyden, J and Lebeer, S}, title = {Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation.}, journal = {PloS one}, volume = {11}, number = {8}, pages = {e0161337}, pmid = {27537843}, issn = {1932-6203}, support = {R24 GM098791/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Adhesion ; Biofilms/*drug effects/growth & development ; Epithelial Cells/microbiology ; Escherichia coli/*drug effects/growth & development/physiology ; Gene Knockout Techniques ; Humans ; Lacticaseibacillus rhamnosus/genetics/*metabolism/physiology ; Lectins/genetics/metabolism/*pharmacology ; Recombinant Proteins ; Salmonella/*drug effects/growth & development/physiology ; Salmonella typhimurium/drug effects/growth & development/physiology ; Sequence Analysis, DNA ; }, abstract = {OBJECTIVES: Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties.

METHODS: The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening.

RESULTS: The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells.

CONCLUSIONS: Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections.}, } @article {pmid27536298, year = {2016}, author = {El-Khoury, N and Majed, R and Perchat, S and Kallassy, M and Lereclus, D and Gohar, M}, title = {Spatio-Temporal Evolution of Sporulation in Bacillus thuringiensis Biofilm.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1222}, pmid = {27536298}, issn = {1664-302X}, abstract = {Bacillus thuringiensis can produce a floating biofilm which includes two parts: a ring and a pellicle. The ring is a thick structure which sticks to the culture container, while the pellicle extends over the whole liquid surface and joins the ring. We have followed over time, from 16 to 96 h, sporulation in the two biofilm parts. Sporulation was followed in situ in 48-wells polystyrene microtiterplates with a fluorescence binocular stereomicroscope and a spoIID-yfp transcriptional fusion. Sporulation took place much earlier in the ring than in the pellicle. In 20 h-aged biofilms, spoIID was expressed only in the ring, which could be seen as a green fluorescent circle surrounding the non-fluorescent pellicle. However, after 48 h of culture, the pellicle started to express spoIID in specific area corresponding to protrusions, and after 96 h both the ring and the whole pellicle expressed spoIID. Spore counts and microscopy observations of the ring and the pellicle harvested separately confirmed these results and revealed that sporulation occured 24 h-later in the pellicle comparatively to the ring, although both structures contained nearly 100% spores after 96 h of culture. We hypothesize that two mechanisms, due to microenvironments in the biofilm, can explain this difference. First, the ring experiences a decreased concentration of nutrients earlier than the pellicle, because of a lower exchange area with the culture medium. An second, the ring is exposed to partial dryness. Both reasons could speed up sporulation in this biofilm structure. Our results also suggest that spores in the biofilm display a phenotypic heterogeneity. These observations might be of particular significance for the food industry, since the biofilm part sticking to container walls - the ring - is likely to contain spores and will therefore resist both to washing and to cleaning procedures, and will be able to restart a new biofilm when food production has resumed.}, } @article {pmid27535698, year = {2016}, author = {Rathna, J and Bakkiyaraj, D and Pandian, SK}, title = {Anti-biofilm mechanisms of 3,5-di-tert-butylphenol against clinically relevant fungal pathogens.}, journal = {Biofouling}, volume = {32}, number = {9}, pages = {979-993}, doi = {10.1080/08927014.2016.1216103}, pmid = {27535698}, issn = {1029-2454}, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/metabolism/physiology ; Candida albicans/drug effects/metabolism/physiology ; Microbial Sensitivity Tests ; Phenols/isolation & purification/*pharmacology ; Pleurotus/*chemistry ; Reactive Oxygen Species/metabolism ; }, abstract = {The methanolic extract (PFME) of Pleurotus florida was assessed for anti-biofilm activity against Candida species. 3,5-Di-tert-butylphenol (3,5-DTB) was identified as the major antifungal constituent in PFME. In its pure form 3,5-DTB inhibits, disrupts, and reduces the viability of biofilm cells as seen from scanning electron and confocal microscopy studies. Microscopic studies and propidium iodide uptake assays confirmed that 3,5-DTB damages the cell membrane of Candida cells. In addition, 3,5-DTB induces accumulation of reactive oxygen species (ROS) which contribute to its pronounced anti-biofilm activity. The results of the present study show that 3,5-DTB exhibits combined anti-biofilm and conventional fungicidal activity against Candida species and elucidate the underlying mechanisms.}, } @article {pmid27535356, year = {2016}, author = {Bugli, F and Palmieri, V and Torelli, R and Papi, M and De Spirito, M and Cacaci, M and Galgano, S and Masucci, L and Paroni Sterbini, F and Vella, A and Graffeo, R and Posteraro, B and Sanguinetti, M}, title = {In vitro effect of clarithromycin and alginate lyase against helicobacter pylori biofilm.}, journal = {Biotechnology progress}, volume = {32}, number = {6}, pages = {1584-1591}, doi = {10.1002/btpr.2339}, pmid = {27535356}, issn = {1520-6033}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Clarithromycin/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Helicobacter pylori/*drug effects/metabolism ; Microbial Sensitivity Tests ; Polysaccharide-Lyases/*metabolism ; Structure-Activity Relationship ; }, abstract = {It is now established that the gastric pathogen Helicobacter pylori has the ability to form biofilms in vitro as well as on the human gastric mucosa. The aim of this study is to evaluate the antimicrobial effects of Clarithromycin on H. pylori biofilm and to enhance the effects of this antibiotic by combining it with Alginate Lyase, an enzyme degrading the polysaccharides present in the extracellular polymeric matrix forming the biofilm. We evaluated the Clarithromycin minimum inhibition concentration (MIC) on in vitro preformed biofilm of a H. pylori. Then the synergic effect of Clarithromycin and Alginate Lyase treatment has been quantified by using the Fractional Inhibitory Concentration index, measured by checkerboard microdilution assay. To clarify the mechanisms behind the effectiveness of this antibiofilm therapeutic combination, we used Atomic Force Microscopy to analyze modifications of bacterial morphology, percentage of bacillary or coccoid shaped bacteria cells and to quantify biofilm properties. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1584-1591, 2016.}, } @article {pmid27530857, year = {2016}, author = {Maheshwari, M and Ahmad, I and Althubiani, AS}, title = {Multidrug resistance and transferability of blaCTX-M among extended-spectrum β-lactamase-producing enteric bacteria in biofilm.}, journal = {Journal of global antimicrobial resistance}, volume = {6}, number = {}, pages = {142-149}, doi = {10.1016/j.jgar.2016.04.009}, pmid = {27530857}, issn = {2213-7173}, mesh = {*Biofilms ; *Drug Resistance, Multiple, Bacterial ; Enterobacteriaceae/drug effects/*enzymology/genetics ; Hospitals ; Wastewater/microbiology ; beta-Lactamases/*genetics ; }, abstract = {This study aimed to investigate the occurrence of biofilm-forming extended-spectrum β-lactamase (ESBL)-producing enteric bacteria in hospital wastewater and to evaluate their antibiotic resistance behaviour and transferability of the plasmid-encoded blaCTX-M gene in biofilm. ESBL production was confirmed using the combined disc test and Etest. Amplification of blaCTX-M was performed by PCR. Antibiotic susceptibility was evaluated using the disc diffusion assay and broth dilution method. Transfer of blaCTX-M in planktonic and biofilm state was performed by broth mating and filter mating experiments, respectively. Among 110 enteric bacteria, 24 (21.8%) isolates belonging to Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae were found to produce ESBL and formed varying levels of biofilm in vitro. Presence of blaCTX-M was detected in 18 (75%) ESBL-producing isolates. A many fold increase in resistance to antibiotics was observed in biofilm. Among ESBL-producers, seven isolates could transfer the blaCTX-M gene by conjugation, with transfer frequencies ranging from 2.22×10(-4) to 7.14×10(-2) transconjugants/recipient cell in the planktonic state and from 3.04×10(-3) to 9.15×10(-1) in biofilm. The transfer frequency of blaCTX-M was significantly higher in biofilm compared with the planktonic state, and co-transfer of ciprofloxacin resistance was also detected in five isolates. This study demonstrates that biofilm-forming ESBL-producing enteric bacteria with a greater transfer frequency of resistance genes will lead to frequent dissemination of β-lactam and fluoroquinolone resistance genes in environmental settings. The emergence and spread of such multidrug resistance is a serious threat to animal and public health.}, } @article {pmid27529383, year = {2016}, author = {Park, JH and Choi, O and Lee, TH and Kim, H and Sang, BI}, title = {Pyrosequencing analysis of microbial communities in hollow fiber-membrane biofilm reactors system for treating high-strength nitrogen wastewater.}, journal = {Chemosphere}, volume = {163}, number = {}, pages = {192-201}, doi = {10.1016/j.chemosphere.2016.07.099}, pmid = {27529383}, issn = {1879-1298}, mesh = {Ammonium Compounds/*metabolism ; Animals ; Autotrophic Processes ; Bacteria/classification/*genetics/*isolation & purification/metabolism ; Biofilms ; Bioreactors/*microbiology ; Denitrification ; High-Throughput Nucleotide Sequencing ; Nitrates/*metabolism ; Nitrification ; Sewage/microbiology ; Swine ; Wastewater/*microbiology ; }, abstract = {Wastewaters from swine farms, nitrogen-dealing industries or side-stream processes of a wastewater treatment plant (e.g., anaerobic digesters, sludge thickening processes, etc.) are characterized by low C/N ratios and not easily treatable. In this study, a hollow fiber-membrane biofilm reactors (HF-MBfR) system consisting of an O2-based HF-MBfR and an H2-based HF-MBfR was applied for treating high-strength wastewater. The reactors were continuously operated with low supply of O2 and H2 and without any supply of organic carbon for 250 d. Gradual increase of ammonium and nitrate concentration in the influent showed stable and high nitrogen removal efficiency, and the maximum ammonium and nitrate removal rates were 0.48 kg NH4(+)-N m(-3) d(-1) and 0.55 kg NO3(-)-N m(-3) d(-1), respectively. The analysis of the microbial communities using pyrosequencing analysis indicated that Nitrosospira multiformis, ammonium-oxidizing bacteria, and Nitrobacter winogradskyi and Nitrobacter vulgaris, nitrite-oxidizing bacteria were highly enriched in the O2-based HF-MBfR. In the H2-based HF-MBfR, hydrogenotrophic denitrifying bacteria belonging to the family of Thiobacillus and Comamonadaceae were initially dominant, but were replaced to heterotrophic denitrifiers belonging to Rhodocyclaceae and Rhodobacteraceae utilizing by-products induced from autotrophic denitrifying bacteria. The pyrosequencing analysis of microbial communities indicates that the autotrophic HF-MBfRs system well developed autotrophic nitrifying and denitrifying bacteria within a relatively short period to accomplish almost complete nitrogen removal.}, } @article {pmid27529172, year = {2016}, author = {Kunyanee, C and Kamjumphol, W and Taweechaisupapong, S and Kanthawong, S and Wongwajana, S and Wongratanacheewin, S and Hahnvajanawong, C and Chareonsudjai, S}, title = {Burkholderia pseudomallei Biofilm Promotes Adhesion, Internalization and Stimulates Proinflammatory Cytokines in Human Epithelial A549 Cells.}, journal = {PloS one}, volume = {11}, number = {8}, pages = {e0160741}, pmid = {27529172}, issn = {1932-6203}, mesh = {A549 Cells ; *Bacterial Adhesion ; *Biofilms ; Burkholderia pseudomallei/*physiology ; Cytokines/biosynthesis/*metabolism ; Humans ; Immunity, Innate ; Inflammation/metabolism ; Intracellular Space/microbiology ; Microbial Viability ; Phenotype ; }, abstract = {Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis. Inhalational exposure leading to pulmonary melioidosis is the most common clinical manifestation with significant mortality. However, the role of B. pseudomallei biofilm phenotype during bacterial-host interaction remains unclear. We hypothesize that biofilm phenotype may play a role in such interactions. In this study, B. pseudomallei H777 (biofilm wild type), B. pseudomallei M10 (biofilm mutant) and B. pseudomallei C17 (biofilm-complemented) strains were used to assess the contribution of biofilm to adhesion to human lung epithelial cells (A549), intracellular interactions, apoptosis/necrosis and impact on proinflammatory responses. Confocal laser scanning microscopy demonstrated that B. pseudomallei H777 and C17 produced biofilm, whereas M10 did not. To determine the role of biofilm in host interaction, we assessed the ability of each of the three strains to interact with the A549 cells at MOI 10. Strain H777 exhibited higher levels of attachment and invasion compared to strain M10 (p < 0.05). In addition, the biofilm-complemented strain, C17 exhibited restored bacterial invasion ability. Flow cytometry combined with a double-staining assay using annexin V and propidium iodide revealed significantly higher numbers of early apoptotic and late apoptotic A549 cells when these were infected with strain H777 (1.52%) and C17 (1.43%) compared to strain M10 (0.85%) (p < 0.05). Strains H777 and C17 were able to stimulate significant secretion of IL-6 and IL-8 compared with the biofilm mutant (p < 0.05). Together, these findings demonstrated the role of biofilm-associated phenotypes of B. pseudomallei in cellular pathogenesis of human lung epithelial cells with respect to initial attachment and invasion, apoptosis and proinflammatory responses.}, } @article {pmid27527785, year = {2016}, author = {Brilhante, RSN and Oliveira, JS and Evangelista, AJJ and Serpa, R and Silva, ALD and Aguiar, FRM and Pereira, VS and Castelo-Branco, DSCM and Pereira-Neto, WA and Cordeiro, RA and Sidrim, JJC and Rocha, MFG}, title = {Candida tropicalis from veterinary and human sources shows similar in vitro hemolytic activity, antifungal biofilm susceptibility and pathogenesis against Caenorhabditis elegans.}, journal = {Veterinary microbiology}, volume = {192}, number = {}, pages = {213-219}, doi = {10.1016/j.vetmic.2016.07.022}, pmid = {27527785}, issn = {1873-2542}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Caenorhabditis elegans/*microbiology ; Candida tropicalis/*physiology ; Candidiasis/microbiology/*veterinary ; Drug Resistance, Fungal ; Humans ; }, abstract = {The aim of this study was to evaluate the in vitro hemolytic activity and biofilm antifungal susceptibility of veterinary and human Candida tropicalis strains, as well as their pathogenesis against Caenorhabditis elegans. Twenty veterinary isolates and 20 human clinical isolates of C. tropicalis were used. The strains were evaluated for their hemolytic activity and biofilm production. Biofilm susceptibility to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin was assessed using broth microdilution assay. The in vivo evaluation of strain pathogenicity was investigated using the nematode C. elegans. Hemolytic factor was observed in 95% of the strains and 97.5% of the isolates showed ability to form biofilm. Caspofungin and amphotericin B showed better results than azole antifungals against mature biofilms. Paradoxical effect on mature biofilm metabolic activity was observed at elevated concentrations of caspofungin (8-64μg/mL). Azole antifungals were not able to inhibit mature C. tropicalis biofilms, even at the higher tested concentrations. High mortality rates of C. elegans were observed when the worms were exposed to with C. tropicalis strains, reaching up to 96%, 96h after exposure of the worms to C. tropicalis strains. These results reinforce the high pathogenicity of C. tropicalis from veterinary and human sources and show the effectiveness of caspofungin and amphotericin B against mature biofilms of this species.}, } @article {pmid27527086, year = {2016}, author = {Chuang, YM and Dutta, NK and Hung, CF and Wu, TC and Rubin, H and Karakousis, PC}, title = {Stringent Response Factors PPX1 and PPK2 Play an Important Role in Mycobacterium tuberculosis Metabolism, Biofilm Formation, and Sensitivity to Isoniazid In Vivo.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {11}, pages = {6460-6470}, pmid = {27527086}, issn = {1098-6596}, support = {R01 HL106786/HL/NHLBI NIH HHS/United States ; UH2 AI122309/AI/NIAID NIH HHS/United States ; }, mesh = {Acid Anhydride Hydrolases/deficiency/*genetics ; Animals ; Antitubercular Agents/*pharmacology ; Biofilms/drug effects/growth & development ; Citric Acid Cycle/genetics ; Clofazimine/pharmacology ; Disease Models, Animal ; Drug Resistance, Bacterial/*genetics ; Gene Expression ; Glycerophosphates/metabolism ; Isoenzymes/deficiency/genetics ; Isoniazid/*pharmacology ; Meropenem ; Mice ; Mycobacterium tuberculosis/drug effects/enzymology/genetics/growth & development ; Naphthoquinones/pharmacology ; Phosphotransferases (Phosphate Group Acceptor)/deficiency/*genetics ; Polyphosphates/metabolism ; Thienamycins/pharmacology ; Tuberculosis Vaccines/*administration & dosage ; Tuberculosis, Multidrug-Resistant/*drug therapy/immunology/microbiology/prevention & control ; Vaccines, DNA/administration & dosage ; Xylose/analogs & derivatives/metabolism ; }, abstract = {Mycobacterium tuberculosis remains a global health threat largely due to the lengthy duration of curative antibiotic treatment, contributing to medical nonadherence and the emergence of drug resistance. This prolonged therapy is likely due to the presence of M. tuberculosis persisters, which exhibit antibiotic tolerance. Inorganic polyphosphate [poly(P)] is a key regulatory molecule in the M. tuberculosis stringent response mediating antibiotic tolerance. The polyphosphate kinase PPK1 is responsible for poly(P) synthesis in M. tuberculosis, while the exopolyphosphatases PPX1 and PPX2 and the GTP synthase PPK2 are responsible for poly(P) hydrolysis. In the present study, we show by liquid chromatography-tandem mass spectrometry that poly(P)-accumulating M. tuberculosis mutant strains deficient in ppx1 or ppk2 had significantly lower intracellular levels of glycerol-3-phosphate (G3P) and 1-deoxy-xylulose-5-phosphate. Real-time PCR revealed decreased expression of genes in the G3P synthesis pathway in each mutant. The ppx1-deficient mutant also showed a significant accumulation of metabolites in the tricarboxylic acid cycle, as well as altered arginine and NADH metabolism. Each poly(P)-accumulating strain showed defective biofilm formation, while deficiency of ppk2 was associated with increased sensitivity to plumbagin and meropenem and deficiency of ppx1 led to enhanced susceptibility to clofazimine. A DNA vaccine expressing ppx1 and ppk2, together with two other members of the M. tuberculosis stringent response, M. tuberculosis rel and sigE, did not show protective activity against aerosol challenge with M. tuberculosis, but vaccine-induced immunity enhanced the killing activity of isoniazid in a murine model of chronic tuberculosis. In summary, poly(P)-regulating factors of the M. tuberculosis stringent response play an important role in M. tuberculosis metabolism, biofilm formation, and antibiotic sensitivity in vivo.}, } @article {pmid27527084, year = {2016}, author = {Pulido, D and Prats-Ejarque, G and Villalba, C and Albacar, M and González-López, JJ and Torrent, M and Moussaoui, M and Boix, E}, title = {A Novel RNase 3/ECP Peptide for Pseudomonas aeruginosa Biofilm Eradication That Combines Antimicrobial, Lipopolysaccharide Binding, and Cell-Agglutinating Activities.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {6313-6325}, pmid = {27527084}, issn = {1098-6596}, mesh = {Agglutination/drug effects ; Animals ; Anti-Bacterial Agents/metabolism/*pharmacology ; Biofilms/drug effects ; Eosinophil Cationic Protein/*chemistry ; Erythrocytes/drug effects ; Humans ; Lipopolysaccharides/*metabolism ; Microbial Sensitivity Tests ; Peptide Fragments/chemistry/pharmacology ; Plankton/microbiology ; Pseudomonas aeruginosa/*drug effects/metabolism/physiology ; }, abstract = {Eradication of established biofilm communities of pathogenic Gram-negative species is one of the pending challenges for the development of new antimicrobial agents. In particular, Pseudomonas aeruginosa is one of the main dreaded nosocomial species, with a tendency to form organized microbial communities that offer an enhanced resistance to conventional antibiotics. We describe here an engineered antimicrobial peptide (AMP) which combines bactericidal activity with a high bacterial cell agglutination and lipopolysaccharide (LPS) affinity. The RN3(5-17P22-36) peptide is a 30-mer derived from the eosinophil cationic protein (ECP), a host defense RNase secreted by eosinophils upon infection, with a wide spectrum of antipathogen activity. The protein displays high biofilm eradication activity that is not dependent on its RNase catalytic activity, as evaluated by using an active site-defective mutant. On the other hand, the peptide encompasses both the LPS-binding and aggregation-prone regions from the parental protein, which provide the appropriate structural features for the peptide's attachment to the bacterial exopolysaccharide layer and further improved removal of established biofilms. Moreover, the peptide's high cationicity and amphipathicity promote the cell membrane destabilization action. The results are also compared side by side with other reported AMPs effective against either planktonic and/or biofilm forms of Pseudomonas aeruginosa strain PAO1. The ECP and its derived peptide are unique in combining high bactericidal potency and cell agglutination activity, achieving effective biofilm eradication at a low micromolar range. We conclude that the designed RN3(5-17P22-36) peptide is a promising lead candidate against Gram-negative biofilms.}, } @article {pmid27526691, year = {2016}, author = {Groizeleau, J and Rybtke, M and Andersen, JB and Berthelsen, J and Liu, Y and Yang, L and Nielsen, TE and Kaever, V and Givskov, M and Tolker-Nielsen, T}, title = {The anti-cancerous drug doxorubicin decreases the c-di-GMP content in Pseudomonas aeruginosa but promotes biofilm formation.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {10}, pages = {1797-1807}, doi = {10.1099/mic.0.000354}, pmid = {27526691}, issn = {1465-2080}, mesh = {Antineoplastic Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Cyclic GMP/*analogs & derivatives/metabolism ; Doxorubicin/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; }, abstract = {Current antibiotic treatments are insufficient in eradicating bacterial biofilms, which represent the primary cause of chronic bacterial infections. Thus, there is an urgent need for new strategies to eradicate biofilm infections. The second messenger c-di-GMP is a positive regulator of biofilm formation in many clinically relevant bacteria. It is hypothesized that drugs lowering the intracellular level of c-di-GMP will force biofilm bacteria into a more treatable planktonic lifestyle. To identify compounds capable of lowering c-di-GMP levels in Pseudomonas aeruginosa, we screened 5000 compounds for their potential c-di-GMP-lowering effect using a recently developed c-di-GMP biosensor strain. Our screen identified the anti-cancerous drug doxorubicin as a potent c-di-GMP inhibitor. In addition, the drug decreased the transcription of many biofilm-related genes. However, despite its effect on the c-di-GMP content in P. aeruginosa, doxorubicin was unable to inhibit biofilm formation or disperse established biofilms. On the contrary, the drug was found to promote P. aeruginosa biofilm formation, possibly through release of extracellular DNA from a subpopulation of killed bacteria. Our findings emphasize that lowering of the c-di-GMP content in bacteria might not be sufficient to mediate biofilm inhibition or dispersal.}, } @article {pmid27526087, year = {2016}, author = {Zheng, D and Chang, Q and Gao, M and She, Z and Jin, C and Guo, L and Zhao, Y and Wang, S and Wang, X}, title = {Performance evaluation and microbial community of a sequencing batch biofilm reactor (SBBR) treating mariculture wastewater at different chlortetracycline concentrations.}, journal = {Journal of environmental management}, volume = {182}, number = {}, pages = {496-504}, doi = {10.1016/j.jenvman.2016.08.003}, pmid = {27526087}, issn = {1095-8630}, mesh = {Bacteria/*metabolism ; Biofilms/*drug effects ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Chlortetracycline/analysis/*chemistry ; Microbial Consortia ; Nitrogen/chemistry/*metabolism ; Phylogeny ; Wastewater/*chemistry ; Water Pollutants, Chemical/analysis ; }, abstract = {The effects of chlortetracycline (CTC) on the performance, microbial activity, extracellular polymeric substances (EPS) and microbial community of a sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater. Low CTC concentration (less than 6 mg/L) had no obvious effect on the SBBR performance, whereas high CTC concentration could inhibit the chemical oxygen demand (COD) and nitrogen removal of the SBBR. The microbial activity of the biofilm in the SBBR decreased with the increase of CTC concentration from 0 to 35 mg/L. The protein (PN) contents were always higher than the PS contents in both loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) at different CTC concentrations. The chemical compositions of LB-EPS and TB-EPS had obvious variations with the increase of CTC concentration from 0 to 35 mg/L. The high-throughput sequencing revealed the effects of CTC on the microbial communities of the biofilm at phylum, class and genus level. The relative abundances of some genera displayed a decreasing tendency with the increase of CTC concentration from 0 to 35 mg/L, such as Nitrospira, Paracoccus, Hyphomicrobium, Azospirillum. However, the relative abundances of the genera Flavobacterium, Aequorivita, Buchnera, Azonexus and Thioalbus increased with the increase of CTC concentration.}, } @article {pmid27525391, year = {2016}, author = {Baba, S and Aydın, MD}, title = {[Investigation of the serotype distribution, biofilm production and antibiotic susceptibilities of group B streptococci isolated from urinary samples].}, journal = {Mikrobiyoloji bulteni}, volume = {50}, number = {3}, pages = {353-360}, doi = {10.5578/mb.26466}, pmid = {27525391}, issn = {0374-9096}, mesh = {Adult ; Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Female ; Humans ; Male ; Serotyping ; Streptococcal Infections/*microbiology ; *Streptococcus agalactiae/classification/drug effects/physiology ; Urinary Tract Infections/*microbiology ; }, abstract = {Streptococcus agalactiae (Group B streptococcus, GBS), a member of normal flora of human gastrointestinal and genitourinary systems, is a leading cause of sepsis, meningitis, and pneumonia particularly in newborn. GBS can also cause severe infections in pregnant women and adults with underlying disease, as well as mild diseases, such as urinary tract infections (UTIs). GBS strains exhibit 10 different serotypes, and the identification of serotype distribution is important epidemiologically. The role of biofilm production is one of the virulence factors that has been discussed in the pathogenesis of GBS infections. Although resistance to penicillin and ampicillin has not been documented in GBS, different rates of resistance has been reported for the alternative antibiotics to penicillin. The aim of this study was to investigate the serotype distribution, the ability of biofilm formation and the antibiotic susceptibilities of S.agalactiae strains isolated from urine cultures. A total of 60 strains were included in the study, 40 of them were isolated from patients (38 female 2 male; mean age: 36.7 years) with urinary tract complaints whose cultures yielded single type of colonies in the number of ≥ 50.000 cfu/ml, whereas 20 of them were isolated from patients (19 female 1 male; mean age: 37.2 years) without urinary tract complaints whose cultures yielded mixed colonies in the number of ≤ 20.000 cfu/ml. Chromogenic media were used for the isolation and the isolates were identified by conventional methods. The isolates were then serotyped by latex agglutination method and their antibiotic susceptibilities were determined by disk diffusion method recommended by CLSI documents. Biofilm formation of the strains were investigated by microplate and Congo red agar (CRA) methods. In our study, the most frequently detected serotypes were V (n= 18; 30%) and II (n= 14; 23.3%), followed by serotype Ia (n= 10; 16.7%), III (n= 9; 15%), Ib (n= 3; 5%), VI (n= 1; 1.7%) and VII (n= 1; 1.7%). Serotype IV, VIII and IX were not detected, while four (6.7%) isolates were untypeable. Serotype V (13/40; 32.5%) and serotip II (6/20; 30%) were in the first line among the strains isolated from patient and control groups, respectively. All of the GBS isolates were found susceptible to penicillin, vancomycin and cefotaxime. The rates of resistance against ofloxacin, erythromycin and clindamycin in patient group were found as 22.5%, %10 and 5%, respectively. In the control group resistance rates against erythromycin and clindamycin were both 10%, while no resistance was detected to the other antibiotics. The ofloxacin resistance in the patient group was found significantly higher than that of control group (p= 0.02). By microplate method, the percentage of moderate/strong biofilm producers was found as 42.5% (17/40) in the patient group and 20% (4/20) in the control group, however the difference between the groups was not statistically significant (p= 0.08). All GBS strains were detected as positive by the CRA method, and it has been suggested that this might have been due to the binding of Congo red to sialic acid found in the GBS capsule, therefore this method thought to be improper for the investigation of biofilm formation in GBS strains. In conclusion, the most frequent serotypes of the GBS urinary isolates in our study were similar with the frequent serotypes reported in other studies. Our data have pointed out that the biofilm formation of GBS may not play a role in the pathogenesis of UTIs. In the meantime the high quinolone resistance detected in our study should be considered in the treatment of UTI due to GBS.}, } @article {pmid27523661, year = {2016}, author = {Rahim, K and Qasim, M and Rahman, H and Khan, TA and Ahmad, I and Khan, N and Ullah, A and Basit, A and Saleha, S}, title = {Antimicrobial resistance among aerobic biofilm producing bacteria isolated from chronic wounds in the tertiary care hospitals of Peshawar, Pakistan.}, journal = {Journal of wound care}, volume = {25}, number = {8}, pages = {480-486}, doi = {10.12968/jowc.2016.25.8.480}, pmid = {27523661}, issn = {0969-0700}, mesh = {Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*therapeutic use ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Chronic Disease/drug therapy ; Diabetic Foot/*drug therapy/*microbiology ; Drug Resistance, Microbial/*drug effects ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pakistan ; Tertiary Care Centers ; }, abstract = {OBJECTIVE: Chronic wound infections impose major medical and economic costs on health-care systems, cause significant morbidity, mortality and prolonged hospitalisation. The presence of biofilm producing bacteria in these wounds is considered as an important virulence factor that leads to chronic implications including ulceration. The undertaken study aimed to isolate and identify the biofilm aerobic bacterial pathogens from patients with chronic wound infections, and determine their antibiotics resistance profiles Method: During this study, swab specimens were collected from patients with chronic wounds at teaching hospitals of Peshawar, Pakistan between May 2013 and June 2014. The isolated aerobic bacterial pathogens were identified on the basis of standard cultural characteristics and biochemical tests. Antibiotics resistance profiles of biofilm producing bacteria against selected antibiotics were then determined.

RESULTS: Among the chronic wound infections, diabetic foot ulcers were most common 37 (37%), followed by surgical ulcers 27 (27%). Chronic wounds were common in male patients older than 40 years. Among the total 163 isolated bacterial pathogens the most prevalent bacterial species were Pseudomonas aeruginosa 44 (27%), Klebsiella pneumoniae 26 (16%), Staphylococcus species 22 (14%) and Streptococcus spp. 21 (13%). The isolation rate of bacterial pathogens was high among patients with diabetic foot ulcers 83 (50.9%). Among bacterial isolates, 108 (66.2%) were observed as biofilm producers while 55 (33.8%) did not form biofilm in our model. The investigated biofilm producing bacterial isolates showed comparatively high resistance against tested antibiotics compared to non-biofilm producing bacterial isolates. The most effective antibiotics were amikacine and cefepime against all isolates.

CONCLUSION: Increased multidrug resistance in biofilm producing bacteria associated with chronic wounds was observed in this study. Judicious use of antibiotics is needed to control the wound associated biofilm associated pathogens.}, } @article {pmid27522461, year = {2016}, author = {Suresh, L and Sagar Vijay Kumar, P and Poornachandra, Y and Ganesh Kumar, C and Chandramouli, GV}, title = {An efficient one-pot synthesis of thiochromeno[3,4-d]pyrimidines derivatives: Inducing ROS dependent antibacterial and anti-biofilm activities.}, journal = {Bioorganic chemistry}, volume = {68}, number = {}, pages = {159-165}, doi = {10.1016/j.bioorg.2016.08.006}, pmid = {27522461}, issn = {1090-2120}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Bacillus subtilis/*drug effects/metabolism ; Biofilms/*drug effects ; Chromans/chemical synthesis/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Molecular Structure ; Pyrimidines/chemical synthesis/chemistry/*pharmacology ; Reactive Oxygen Species/*metabolism ; Staphylococcus aureus/*drug effects/metabolism ; Structure-Activity Relationship ; }, abstract = {An efficient synthesis of thiochromeno[3,4-d]pyrimidine derivatives has been achieved successfully via a one-pot three-component reaction of thiochrome-4-one, aromatic aldehyde and thiourea in the presence of 1-butyl-3-methyl imidazolium hydrogen sulphate [Bmim]HSO4. This new protocol has the advantages of environmental friendliness, high yields, short reaction times, and convenient operation. Furthermore, among all the tested derivatives, compounds 4b and 4c exhibited promising antibacterial, minimum bactericidal concentration and anti-biofilm activities against Staphylococcus aureus MTCC 96, Staphylococcus aureus MLS16 MTCC 2940 and Bacillus subtilis MTCC 121. The compound 4c also showed promising intracellular ROS accumulation in Staphylococcus aureus MLS16 MTCC 2940 comparable to that of ciprofloxacin resulting in apoptotic cell death of the bacterium.}, } @article {pmid27522284, year = {2016}, author = {Piqué, G and Vericat, D and Sabater, S and Batalla, RJ}, title = {Effects of biofilm on river-bed scour.}, journal = {The Science of the total environment}, volume = {572}, number = {}, pages = {1033-1046}, doi = {10.1016/j.scitotenv.2016.08.009}, pmid = {27522284}, issn = {1879-1026}, mesh = {*Biofilms ; Geologic Sediments/*analysis ; *Hydrodynamics ; *Rivers ; Spain ; }, abstract = {Biofilm acts stabilising river-bed sediments, interfering with particle entrainment and, consequently, preventing bed disturbance. In this paper we present the results of a series of experiments carried out in indoor channels, aimed to understand biofilm alteration of bed material motion and topographic changes in stream channels. We analysed the erosion patterns and bedload rates in non-cohesive sediments in channels colonised by biofilms and compared them to biofilm-free others. All the channels had the same conditions of light irradiance, temperature, slope, and particle size (sand). Discharge and water surface slope were modified to create a range of hydraulic conditions, with pairs of colonised and non-colonised channels subjected to the same flows. We observed that biofilm slightly modified bed roughness and flow hydraulics, but that highly influenced bed disturbance. Biofilm caused bed scour to occur in patches unevenly distributed along the channel length, as a result of localised weaknesses of the biofilm. Once biofilm was ripped up it was transported in chunks, and sand grains were observed attached to these chunks. In non-colonised sediments the erosion was more homogeneous and the formation and movement of bedforms were observed. On average, bedload rates were 5 times lower when biofilm was present. Overall, the protective effect of the biofilm prevented generalised erosion of the channel and delayed the entrainment and transport of sand grains. Results emphasised the important role of biofilm in the incipient motion of bed-material in stream channels; this role may affect the magnitude and frequency of subsequent river bed processes, notably the onset of bedload and associated channel morpho-dynamics.}, } @article {pmid27522205, year = {2016}, author = {Taşkan, B and Hanay, Ö and Taşkan, E and Erdem, M and Hasar, H}, title = {Hydrogen-based membrane biofilm reactor for tetracycline removal: biodegradation, transformation products, and microbial community.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {21}, pages = {21703-21711}, pmid = {27522205}, issn = {1614-7499}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Hydrogen/*chemistry ; Tetracycline/analysis/*isolation & purification/metabolism ; Water Pollutants, Chemical/analysis/*isolation & purification/metabolism ; }, abstract = {Tetracycline (TC) in aqueous environment could be reductively degraded by using a hydrogen-based membrane biofilm reactor (H2-MBfR) under denitrifying conditions as it provides an appropriate environment for the antibiotic-degrading bacteria in biofilm communities. This study evaluates the performance of H2-MBfR for simultaneous removal of nitrate and TC, formation of degradation products of TC, and community analysis of the biofilm grown on the gas-permeable hollow fiber membranes. Hence, a H2-MBfR receiving approximately 20 mg N/l nitrate and 0.5 mg/l TC was operated under different H2 pressures, hydraulic retention times (HRTs), and influent TC concentrations in order to provide various nitrate and TC loadings. The results showed that H2-MBfR accomplished successfully the degradation of TC, and it reached TC removal of 80-95 % at 10 h of HRT and 6 psi (0.41 atm) of H2 gas pressure. TC degradation took placed at increased HRT and H2 pressures while nitrate was the preferred electron acceptor for most of the electrons generated from H2 oxidation used for denitrification. The transformation products of TC were found at part per billion levels through all the experiments, and the concentrations decreased with the increasing HRT regardless of H2 pressure. Analyses from clone library showed that the microbial diversity at the optimal conditions was higher than that at the other periods. The dominant species were revealed to be Betaproteobacteria, Acidovorax caeni, and Alicycliphilus denitrificans.}, } @article {pmid27521618, year = {2016}, author = {Liu, Y and Kamesh, AC and Xiao, Y and Sun, V and Hayes, M and Daniell, H and Koo, H}, title = {Topical delivery of low-cost protein drug candidates made in chloroplasts for biofilm disruption and uptake by oral epithelial cells.}, journal = {Biomaterials}, volume = {105}, number = {}, pages = {156-166}, pmid = {27521618}, issn = {1878-5905}, support = {R01 EY024564/EY/NEI NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 HL107904/HL/NHLBI NIH HHS/United States ; R01 HL109442/HL/NHLBI NIH HHS/United States ; R01 GM063879/GM/NIGMS NIH HHS/United States ; }, mesh = {Administration, Topical ; Anti-Bacterial Agents/administration & dosage/chemistry/pharmacokinetics ; Antimicrobial Cationic Peptides/*administration & dosage/chemistry/*pharmacokinetics ; Biofilms/*drug effects/*growth & development ; Cell Line ; Cells, Cultured ; Chloroplasts/*metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells/cytology/*metabolism/microbiology ; Humans ; Mouth Mucosa/cytology/*metabolism/microbiology ; Plant Extracts/administration & dosage/chemistry/pharmacokinetics ; Treatment Outcome ; }, abstract = {Protein drugs (PD) are minimally utilized in dental medicine due to high cost and invasive surgical delivery. There is limited clinical advancement in disrupting virulent oral biofilms, despite their high prevalence in causing dental caries. Poor efficacy of antimicrobials following topical treatments or to penetrate and disrupt formed biofilms is a major challenge. We report an exciting low-cost approach using plant-made antimicrobial peptides (PMAMPs) retrocyclin or protegrin with complex secondary structures (cyclic/hairpin) for topical use to control biofilms. The PMAMPs rapidly killed the pathogen Streptococcus mutans and impaired biofilm formation following a single topical application of tooth-mimetic surface. Furthermore, we developed a synergistic approach using PMAMPs combined with matrix-degrading enzymes to facilitate their access into biofilms and kill the embedded bacteria. In addition, we identified a novel role for PMAMPs in delivering drugs to periodontal and gingival cells, 13-48 folds more efficiently than any other tested cell penetrating peptides. Therefore, PDs fused with protegrin expressed in plant cells could potentially play a dual role in delivering therapeutic proteins to gum tissues while killing pathogenic bacteria when delivered as topical oral formulations or in chewing gums. Recent FDA approval of plant-produced PDs augurs well for clinical advancement of this novel concept.}, } @article {pmid27521261, year = {2016}, author = {Neguţ, AC and Chifiriuc, MC and Săndulescu, O and Streinu-Cercel, A and Oprea, M and Drăgulescu, EC and Gheorghe, I and Berciu, I and Coralia, B and Popa, M and Oţelea, D and Tălăpan, D and Dorobăţ, O and Codiţă, I and Popa, MI and Streinu-Cercel, A}, title = {Bacteriophage-driven inhibition of biofilm formation in Staphylococcus strains from patients attending a Romanian reference center for infectious diseases.}, journal = {FEMS microbiology letters}, volume = {363}, number = {18}, pages = {}, doi = {10.1093/femsle/fnw193}, pmid = {27521261}, issn = {1574-6968}, abstract = {The increasing burden of invasive biofilm-related staphylococcal infections has led to a dire need for new agents to prevent biofilm formation. Bacteriophages may hypothetically alter a biofilm through several mechanisms, including induction of depolymerizing enzymes and lysis of persistent bacteria. We have assessed the influence of commercially available bacteriophage cocktails on Staphylococcus spp. clinical strains viability and biofilm formation. We analyzed 83 staphylococcal strains from patients consecutively admitted to a Romanian infection reference center from October 2014 through May 2015; the strains were characterized by phenotypic and genetic tools for their resistance and virulence features and for their phyliation. Experiments were performed in triplicate. Methicillin-susceptible strains were significantly more susceptible to all tested phages: 1.7-fold higher susceptibility for PYO, 1.4-fold for INTESTI, 2.9-fold for PHAGYO, 2.7-fold for PHAGESTI and 3.9-fold for STAPHYLOCOCCAL; t030 strains were significantly more susceptible to PYO and INTESTI compared with t127 strains. We identified a significant decrease in biofilm formation in the presence of both low and high PYO and INTESTI concentrations (P < 0.001). In conclusion, Staphylococcus strains from Romania displayed fairly good susceptibility to commercially available bacteriophages. We have also ascertained there is phage-driven in vitro inhibition of biofilm formation, the results potentially impacting prevention of prosthetic infections.}, } @article {pmid27516318, year = {2016}, author = {Aiassa, V and Zoppi, A and Becerra, MC and Albesa, I and Longhi, MR}, title = {Enhanced inhibition of bacterial biofilm formation and reduced leukocyte toxicity by chloramphenicol:β-cyclodextrin:N-acetylcysteine complex.}, journal = {Carbohydrate polymers}, volume = {152}, number = {}, pages = {672-678}, doi = {10.1016/j.carbpol.2016.07.013}, pmid = {27516318}, issn = {1879-1344}, mesh = {*Acetylcysteine/chemistry/pharmacology ; Biofilms/*drug effects ; *Chloramphenicol/chemistry/pharmacology ; Humans ; Leukocytes/*metabolism ; Staphylococcus aureus/*physiology ; *beta-Cyclodextrins/chemistry/pharmacology ; }, abstract = {The purpose of this study was to improve the physicochemical and biological properties of chloramphenicol (CP) by multicomponent complexation with β-cyclodextrin (β-CD) and N-acetylcysteine (NAC). The present work describes the ability of solid multicomponent complex (MC) to decrease biomass and cellular activity of Staphylococcus by crystal violet and XTT assay, and leukocyte toxicity, measuring the increase of reactive oxygen species by chemiluminescence, and using 123-dihydrorhodamine. In addition, MC was prepared by the freeze-drying or physical mixture methods, and then characterized by scanning electron microscopy and powder X-ray diffraction. Nuclear magnetic resonance and phase solubility studies provided information at the molecular level on the structure of the MC and its association binding constants, respectively. The results obtained allowed us to conclude that MC formation is an effective pharmaceutical strategy that can reduce CP toxicity against leukocytes, while enhancing its solubility and antibiofilm activity.}, } @article {pmid27515531, year = {2016}, author = {Esteban Florez, FL and Hiers, RD and Smart, K and Kreth, J and Qi, F and Merritt, J and Khajotia, SS}, title = {Real-time assessment of Streptococcus mutans biofilm metabolism on resin composite.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {32}, number = {10}, pages = {1263-1269}, pmid = {27515531}, issn = {1879-0097}, support = {R01 DE018893/DE/NIDCR NIH HHS/United States ; R01 DE021726/DE/NIDCR NIH HHS/United States ; R01 DE022083/DE/NIDCR NIH HHS/United States ; R15 DE019566/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents ; *Biofilms ; Biological Assay ; *Composite Resins ; *Dental Materials ; Luminescent Measurements ; *Streptococcus mutans ; }, abstract = {OBJECTIVE: The release of unpolymerized monomers and by-products of resin composites influences biofilm growth and confounds the measurement of metabolic activity. Current assays to measure biofilm viability have critical limitations and are typically not performed on relevant substrates. The objective of the present study was to determine the utility of firefly luciferase assay for quantification of the viability of intact biofilms on a resin composite substrate, and correlate the results with a standard method (viable colony counts).

METHODS: Disk-shaped specimens of a dental resin composite were fabricated, wet-polished, UV-sterilized, and stored in water. Biofilms of Streptococcus mutans (strain UA159 modified by insertion of constitutively expressed firefly luc gene) were grown (1:500 dilution; anaerobic conditions, 24h, 37°C) in two media concentrations (0.35x and 0.65x THY medium supplemented with 0.1% sucrose; n=15/group). An additional group of specimens with biofilms grown in 0.65x+sucrose media was treated with chlorhexidine gluconate solution to serve as the control group. Bioluminescence measurements of non-disrupted biofilms were obtained after addition of d-Luciferin substrate. The adherent biofilms were removed by sonication, and bioluminescence of sonicated bacteria was then measured. Viable colony counts were performed after plating sonicated bacteria on THY agar plates supplemented with spectinomycin. Bioluminescence values and cell counts were correlated using Spearman correlation tests (α=0.05).

RESULTS: Strong positive correlations between viable colony counts and bioluminescence values, both before- and after-sonication, validated the utility of this assay.

SIGNIFICANCE: A novel non-disruptive, real-time bioluminescence assay is presented for quantification of intact S. mutans biofilms grown on a resin composite, and potentially on antibacterial materials and other types of dental biomaterials.}, } @article {pmid27515530, year = {2016}, author = {Mohmmed, SA and Vianna, ME and Penny, MR and Hilton, ST and Mordan, N and Knowles, JC}, title = {A novel experimental approach to investigate the effect of different agitation methods using sodium hypochlorite as an irrigant on the rate of bacterial biofilm removal from the wall of a simulated root canal model.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {32}, number = {10}, pages = {1289-1300}, doi = {10.1016/j.dental.2016.07.013}, pmid = {27515530}, issn = {1879-0097}, mesh = {*Biofilms ; Dental Pulp Cavity ; Humans ; Printing, Three-Dimensional ; Root Canal Irrigants/*therapeutic use ; *Root Canal Preparation ; Sodium Hypochlorite/*therapeutic use ; Therapeutic Irrigation ; }, abstract = {OBJECTIVE: Root canal irrigation is an important adjunct to control microbial infection. This study aimed primarily to develop a transparent root canal model to study in situ Enterococcus faecalis biofilm removal rate and remaining attached biofilm using passive or active irrigation solution for 90s. The change in available chlorine and pH of the outflow irrigant were assessed.

METHODS: A total of forty root canal models (n=10 per group) were manufactured using 3D printing. Each model consisted of two longitudinal halves of an 18mm length simulated root canal with size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3mm of the models for 10days in Brain Heart Infusion broth. Biofilms were stained using crystal violet for visualization. The model halves were reassembled, attached to an apparatus and observed under a fluorescence microscope. Following 60s of 9mL of 2.5% NaOCl irrigation using syringe and needle, the irrigant was either left stagnant in the canal or activated using gutta-percha, sonic and ultrasonic methods for 30s. Images were then captured every second using an external camera. The residual biofilm percentages were measured using image analysis software. The data were analyzed using Kruskal-Wallis test and generalized linear mixed model.

RESULTS: The highest level of biofilm removal was with ultrasonic agitation (90.13%) followed by sonic (88.72%), gutta-percha (80.59%), and passive irrigation group (control) (43.67%) respectively. All agitation groups reduced the available chlorine and pH of NaOCl more than that in the passive irrigation group.

SIGNIFICANCE: The 3D printing method provided a novel model to create a root canal simulation for studying and understanding a real-time biofilm removal under microscopy. Ultrasonic agitation of NaOCl left the least amount of residual biofilm in comparison to sonic and gutta-percha agitation methods.}, } @article {pmid27514952, year = {2016}, author = {Kumar, D and Banerjee, T and Chakravarty, J and Singh, SK and Dwivedi, A and Tilak, R}, title = {Identification, antifungal resistance profile, in vitro biofilm formation and ultrastructural characteristics of Candida species isolated from diabetic foot patients in Northern India.}, journal = {Indian journal of medical microbiology}, volume = {34}, number = {3}, pages = {308-314}, doi = {10.4103/0255-0857.188320}, pmid = {27514952}, issn = {1998-3646}, mesh = {Adult ; Aged ; Amphotericin B/pharmacology ; Antifungal Agents/*pharmacology ; Biofilms/*growth & development ; Candida/*classification/*drug effects/isolation & purification/physiology ; DNA, Fungal/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; DNA, Ribosomal Spacer/chemistry/genetics ; Diabetic Foot/*microbiology ; *Drug Resistance, Fungal ; Female ; Fluconazole/pharmacology ; Humans ; India ; Male ; Microbial Sensitivity Tests ; Microbiological Techniques ; Middle Aged ; Molecular Diagnostic Techniques ; RNA, Ribosomal, 18S/genetics ; RNA, Ribosomal, 28S/genetics ; Sequence Analysis, DNA ; Specimen Handling ; Voriconazole/pharmacology ; }, abstract = {PURPOSE: Diabetic foot ulcers are a serious cause of diagnostic and therapeutic concern. The following study was undertaken to determine the fungal causes of diabetic foot ulcers, with their phenotypic and genotypic characterisation.

MATERIALS AND METHODS: A total of 155 diabetic foot ulcers were studied for 1 year. Deep tissue specimen was collected from the wounds, and crushed samples were plated on Sabouraud dextrose agar with chloramphenicol (0.05 g). Identification was done by growth on cornmeal agar, germ tube formation and urease test. For molecular identification, conserved portion of the 18S rDNA region, the adjacent internal transcribed spacer 1 (ITS1) and a portion of the 28S rDNA region were amplified, using the ITS1 and ITS2 primers. Antifungal susceptibility against voriconazole, fluconazole and amphotericin B was determined by standard broth microdilution method. Biofilm formation was studied in three steps. First, on the surface of wells of microtiter plates followed by quantification of growth by fungal metabolism measurement. Finally, biofilms were analysed by scanning electron microscopy (SEM).

RESULTS: Fungal aetiology was found in 75 patients (48.38%). All were identified as Candida species (100%). The prevalence of different species was Candida tropicalis (34.6%), Candida albicans (29.3%), Candida krusei (16.0%), Candida parapsilosis (10.6%), Candida glabrata (9.33%). All were susceptible to amphotericin B (100%). On microtiter plate, all the isolates were viable within 48 h showing biofilms. The metabolic activity of cells in the biofilm increased with cellular mass, especially in the first 24 h. On SEM, majority showed budding yeast form.

CONCLUSION: Non-albicans Candida spp. with potential biofilm forming ability are emerging as a predominant cause of diabetic foot ulcers.}, } @article {pmid27513646, year = {2016}, author = {Yu, Q and Huang, H and Ren, H and Ding, L and Geng, J}, title = {In situ activity recovery of aging biofilm in biological aerated filter: Surfactants treatment and mechanisms study.}, journal = {Bioresource technology}, volume = {219}, number = {}, pages = {403-410}, doi = {10.1016/j.biortech.2016.07.122}, pmid = {27513646}, issn = {1873-2976}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Glycolipids/chemistry ; Sodium Dodecyl Sulfate/chemistry ; Surface-Active Agents/*chemistry ; }, abstract = {In situ activity recovery of aging biofilm in the biological aerated filter (BAF) is an important but underappreciated problem. Lab-scaled BAFs were established in this study and three kinds of surfactants containing sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) and rhamnolipid were employed. Multiple indicators including effluent qualities, dissolved organic matters, biofilm physiology and morphology characteristics were investigated to explore the mechanisms. Results showed that removal rates of effluent COD in test groups significantly recovered to the level before aging. Compared with the control, effluent in SDBS and rhamnolipid-treated groups obtained more protein-like and humic-like substances, respectively. Furthermore, great live cell ratio, smooth surface and low adhesion force of biofilm were observed after rhamnolipid treatment, which was in consistent with good effluent qualities in the same group. This is the first report of applying rhamnolipid for in situ activity recovery of aging biofilm in bioreactors.}, } @article {pmid27513373, year = {2016}, author = {Aydın, E and Şahin, M and Taşkan, E and Hasar, H and Erdem, M}, title = {Chlortetracycline removal by using hydrogen based membrane biofilm reactor.}, journal = {Journal of hazardous materials}, volume = {320}, number = {}, pages = {88-95}, doi = {10.1016/j.jhazmat.2016.08.014}, pmid = {27513373}, issn = {1873-3336}, mesh = {Biofilms ; Bioreactors/*microbiology ; Chlortetracycline/*isolation & purification ; Feasibility Studies ; Hydrogen ; Nitrates/*isolation & purification ; Water Pollutants, Chemical/*isolation & purification ; }, abstract = {In the last years, increasing attention has been paid on the presence of antibiotics in aqueous environments due to their ecological damage and potential adverse effects on organisms. Membrane biofilm reactors (MBfR) have been gained a significant popularity as an advanced wastewater treatment technology in removing of organic micro-pollutants. In this study, the performance of H2-MBfR for simultaneous removal of nitrate and chlortetracycline, formation of transformation products and community analysis of the biofilm grown on the gas permeable hollow fiber membranes was evaluated by considering effect of the hydraulic retention time, surface loadings of target pollutants and H2 pressure. The results showed that the simultaneous chlortetracycline (96%) and nitrate removal (99%) took placed successfully under the conditions of 5h HRT and 2psi H2 pressure. It has been determined that the main elimination process was biodegradation and Betaproteobacteria species was responsible for chlortetracycline degradation.}, } @article {pmid27508370, year = {2016}, author = {Pan, M and Zhao, J and Zhen, S and Heng, S and Wu, J}, title = {Effects of the combination of aeration and biofilm technology on transformation of nitrogen in black-odor river.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {3}, pages = {655-662}, doi = {10.2166/wst.2016.212}, pmid = {27508370}, issn = {0273-1223}, mesh = {Bacteria/metabolism ; Biodegradation, Environmental ; *Biofilms ; Eutrophication ; Nitrogen/analysis/*metabolism ; Odorants/analysis ; Oxygen/metabolism ; Rivers/*chemistry/microbiology ; Water Pollutants, Chemical/analysis/*metabolism ; Water Purification/*methods ; }, abstract = {Excess nitrogen in urban river networks leading to eutrophication has become one of the most urgent environmental problems. Combinations of different aeration and biofilm techniques was designed to remove nitrogen from rivers. In laboratory water tank simulation experiments, we assessed the removal efficiency of nitrogen in both the overlying water and sediments by using the combination of the aeration and biofilm techniques, and then analyzed the transformation of nitrogen during the experiments. Aeration (especially sediment aeration) combined with the biofilms techniques was proved efficient in removing nitrogen from polluted rivers. Results indicated that the combination of sediment aeration and biofilms, with the highest nitrogen removal rate from the overlying water and sediments, was the most effective combined process, which especially inhibited the potential release of nitrogen from sediments by reducing the enzyme activity. It was found that the content of dissolved oxygen in water could be restored on the basis of the application of aeration techniques ahead, and the biofilm technique would be effective in purifying water in black-odor rivers.}, } @article {pmid27507829, year = {2016}, author = {Reddinger, RM and Luke-Marshall, NR and Hakansson, AP and Campagnari, AA}, title = {Host Physiologic Changes Induced by Influenza A Virus Lead to Staphylococcus aureus Biofilm Dispersion and Transition from Asymptomatic Colonization to Invasive Disease.}, journal = {mBio}, volume = {7}, number = {4}, pages = {}, pmid = {27507829}, issn = {2150-7511}, support = {R01 DC013554/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Cell Line ; Disease Models, Animal ; Epithelial Cells/microbiology/virology ; *Host-Pathogen Interactions ; Humans ; Influenza A virus/*pathogenicity ; Mice, Inbred BALB C ; Orthomyxoviridae Infections/*complications ; Pneumonia, Staphylococcal/*etiology ; Staphylococcus aureus/*pathogenicity/*physiology ; }, abstract = {UNLABELLED: Staphylococcus aureus is a ubiquitous opportunistic human pathogen and a major health concern worldwide, causing a wide variety of diseases from mild skin infections to systemic disease. S. aureus is a major source of severe secondary bacterial pneumonia after influenza A virus infection, which causes widespread morbidity and mortality. While the phenomenon of secondary bacterial pneumonia is well established, the mechanisms behind the transition from asymptomatic colonization to invasive staphylococcal disease following viral infection remains unknown. In this report, we have shown that S. aureus biofilms, grown on an upper respiratory epithelial substratum, disperse in response to host physiologic changes related to viral infection, such as febrile range temperatures, exogenous ATP, norepinephrine, and increased glucose. Mice that were colonized with S. aureus and subsequently exposed to these physiologic stimuli or influenza A virus coinfection developed pronounced pneumonia. This study provides novel insight into the transition from colonization to invasive disease, providing a better understanding of the events involved in the pathogenesis of secondary staphylococcal pneumonia.

IMPORTANCE: In this study, we have determined that host physiologic changes related to influenza A virus infection causes S. aureus to disperse from a biofilm state. Additionally, we report that these same host physiologic changes promote S. aureus dissemination from the nasal tissue to the lungs in an animal model. Furthermore, this study identifies important aspects involved in the transition of S. aureus from asymptomatic colonization to pneumonia.}, } @article {pmid27507109, year = {2016}, author = {Vermote, A and Brackman, G and Risseeuw, MDP and Coenye, T and Van Calenbergh, S}, title = {Design, synthesis and biological evaluation of novel hamamelitannin analogues as potentiators for vancomycin in the treatment of biofilm related Staphylococcus aureus infections.}, journal = {Bioorganic & medicinal chemistry}, volume = {24}, number = {19}, pages = {4563-4575}, doi = {10.1016/j.bmc.2016.07.058}, pmid = {27507109}, issn = {1464-3391}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Drug Design ; Gallic Acid/*analogs & derivatives/chemistry/pharmacology ; Hexoses/*chemistry/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Quorum Sensing/drug effects ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/physiology ; Structure-Activity Relationship ; Vancomycin/*pharmacology ; }, abstract = {Staphylococcus aureus is a frequent cause of biofilm-related infections. Bacterial cells within a biofilm are protected from attack by the immune system and conventional antibiotics often fail to penetrate the biofilm matrix. The discovery of hamamelitannin as a potentiator for antibiotics, recently led to the design of a more drug-like lead. In the present study, we want to gain further insight into the structure-activity relationship (S.A.R.) of the 5-position of the molecule, by preparing a library of 21 hamamelitannin analogues.}, } @article {pmid27505992, year = {2016}, author = {Panariello, BH and Izumida, FE and Moffa, EB and Pavarina, AC and Jorge, JH and Giampaolo, ET}, title = {Effect of mechanical toothbrushing combined with different denture cleansers in reducing the viability of a multispecies biofilm on acrylic resins.}, journal = {American journal of dentistry}, volume = {29}, number = {3}, pages = {154-160}, pmid = {27505992}, issn = {0894-8275}, mesh = {*Acrylic Resins ; *Biofilms ; Candida/drug effects ; *Dentures ; *Disinfection ; Streptococcus mutans/drug effects ; Surface Properties ; Toothbrushing/*methods ; }, abstract = {PURPOSE: To investigate the efficacy of immersion and brushing with different cleansing agents in reducing the viability of multispecies biofilm on acrylic resins.

METHODS: Lucitone 550 (L) and Tokuyama Rebase Fast II (T) specimens (10 x 2 mm) were prepared, sterilized, and inoculated with a suspension of Candida albicans, Candida glabrata, and Streptococcus mutans. Specimens were incubated for 48 hours at 37 degrees C for biofilm formation. Then, they were divided into groups (n = 12) and subjected to brushing or immersion for 10 seconds in distilled water (W), 0.2% peracetic acid-Sterilife (Ac), 1% chlorhexidine digluconate (CHX), 1:1 water/dentifrice solution (D), 1% sodiumhypochlorite (NaOCl), and sodium perborate/Corega Tabs (Pb). Viable microorganisms were evaluated by the XTT assay and colony counts (cfu/mL). Data were performed by ANOVA and Tukey test with 5% significance level.

RESULTS: The multispecies biofilm on L and T were killed by brushing or immersion in Ac, CHX, and NaOCl for only 10 seconds.}, } @article {pmid27505346, year = {2017}, author = {Hansen, LB and Ren, D and Burmølle, M and Sørensen, SJ}, title = {Distinct gene expression profile of Xanthomonas retroflexus engaged in synergistic multispecies biofilm formation.}, journal = {The ISME journal}, volume = {11}, number = {1}, pages = {300-303}, pmid = {27505346}, issn = {1751-7370}, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; Transcriptome ; Xanthomonas/classification/genetics/*physiology ; }, abstract = {It is well known that bacteria often exist in naturally formed multispecies biofilms. Within these biofilms, interspecies interactions seem to have an important role in ecological processes. Little is known about the effects of interspecies interactions on gene expression in these multispecies biofilms. This study presents a comparative gene expression analysis of the Xanthomonas retroflexus transcriptome when grown in a single-species biofilm and in dual- and four-species consortia with Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus. The results revealed complex interdependent interaction patterns in the multispecies biofilms. Many of the regulated functions are related to interactions with the external environment and suggest a high phenotypic plasticity in response to coexistence with other species. Furthermore, the changed expression of genes involved in aromatic and branched-chain amino acid biosynthesis suggests nutrient cross feeding as a contributing factor for the observed synergistic biofilm production when these four species coexists in a biofilm.}, } @article {pmid27505068, year = {2016}, author = {Khoei, NS and Andreolli, M and Lampis, S and Vallini, G and Turner, RJ}, title = {A comparison of the response of two Burkholderia fungorum strains grown as planktonic cells versus biofilm to dibenzothiophene and select polycyclic aromatic hydrocarbons.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {10}, pages = {851-860}, doi = {10.1139/cjm-2016-0160}, pmid = {27505068}, issn = {1480-3275}, mesh = {Biodegradation, Environmental ; Biofilms/drug effects/*growth & development ; Burkholderia/drug effects/*growth & development ; Microbial Viability ; Plankton/drug effects/growth & development ; Polycyclic Aromatic Hydrocarbons/*pharmacology ; Soil Pollutants/pharmacology ; Thiophenes/*pharmacology ; }, abstract = {In natural environments, bacteria often exist in close association with surfaces and interfaces by establishing biofilms. Here, we report on the ability of Burkholderia fungorum strains DBT1 and 95 to survive in high concentrations of hydrocarbons, and we compare their growth as a biofilm vs. planktonic cells. The 2 compounds tested were dibenzothiophene (DBT) and a mixture of naphthalene, phenanthrene, and pyrene (5:2:1) as representative compounds of thiophenes and polycyclic aromatic hydrocarbons (PAHs), respectively. The results showed that both strains were able to degrade DBT and to survive in the presence of up to a 2000 mg·L[-1] concentration of this compound both as a biofilm and as free-living cells. Moreover, B. fungorum DBT1 showed reduced tolerance towards the mixed PAHs (2000 mg·L[-1] naphthalene, 800 mg·L[-1] phenanthrene, and 400 mg·L[-1] pyrene) both as a biofilm and as free-living cells. Conversely, biofilms of B. fungorum 95 enhanced resistance against these toxic compounds compared with planktonic cells (P < 0.05). Visual observation through confocal laser scanning microscopy showed that exposure of biofilms to DBT and PAHs altered their structure: high concentrations of DBT triggered an aggregation of biofilm cells. These findings provide new perspectives on the effectiveness of using DBT-degrading bacterial strains in bioremediation of hydrocarbon-contaminated sites.}, } @article {pmid27504341, year = {2016}, author = {Verma, A and Bhani, D and Tomar, V and Bachhiwal, R and Yadav, S}, title = {Differences in Bacterial Colonization and Biofilm Formation Property of Uropathogens between the Two most Commonly used Indwelling Urinary Catheters.}, journal = {Journal of clinical and diagnostic research : JCDR}, volume = {10}, number = {6}, pages = {PC01-3}, pmid = {27504341}, issn = {2249-782X}, abstract = {INTRODUCTION: Catheter Associated Urinary Tract Infections (CAUTI) are one of the most common cause of nosocomial infections. Many bacterial species show biofilm production, which provides survival benefit to them by providing protection from environmental stresses and causing decreased susceptibility to antimicrobial agents. Two most common types of catheters used in our setup are pure silicone catheter and silicone coated latex catheter. The advantage of pure silicone catheter for long term catheterization is well established. But there is still a controversy about any advantage of the silicone catheter regarding bacterial colonization rates and their biofilm production property.

AIMS: The aim of our study was to compare the bacterial colonization and the biofilm formation property of the colonizing bacteria in patients with indwelling pure silicone and silicone coated latex catheters.

MATERIALS AND METHODS: This prospective observational study was conducted in the Urology Department of our institute. Patients who needed catheterization for more than 5 days during the period July 2015 to January 2016 and had sterile precatheterisation urine were included in the study. Patients were grouped into 2 groups of 50 patients each, Group A with the pure silicone catheter and Group B with the silicone coated latex catheter. Urine culture was done on the 6(th) day of indwelling urinary catheter drainage. If growth was detected, then that bacterium was tested for biofilm production property by tissue culture plate method.

STATISTICAL ANALYSIS: Statistical analyses were performed using the Statistical Package for the Social Science Version 22 (SPSS-22).

RESULTS: After 5 days of indwelling catheterization, the pure silicone catheter had significantly less bacterial colonization than the silicone coated latex catheter (p-value=0.03) and the biofilm forming property of colonizing bacteria was also significantly less in the pure silicone catheter as compared to the silicone coated latex catheter (p-value=0.02). There were no significant differences in the colonizing bacteria in the 2 groups. In both the groups the most common bacteria were Escherichia coli.

CONCLUSION: The pure silicone catheter is advantageous over the silicone coated latex catheter in terms of incidence of bacterial colonization as well as the biofilm formation and hence in the management of CAUTI.}, } @article {pmid27504288, year = {2016}, author = {De, A and Raj, HJ and Maiti, PK}, title = {Biofilm in Osteomyelitis caused by a Rare Pathogen, Morganella morganii : A Case Report.}, journal = {Journal of clinical and diagnostic research : JCDR}, volume = {10}, number = {6}, pages = {DD06-8}, pmid = {27504288}, issn = {2249-782X}, abstract = {Morganella morganii is a member of Enterobacteriaceae family, whose natural habitat is the human gastrointestinal tract. It rarely causes infection alone and is generally encountered in immunosuppressed patients. Osteoarticular pathologies are not commonly observed with Morganella morganii and infections by it have high mortality rate. Biofilm colonization is a causative factor behind the chronicity and/or refractoriness of certain infections. Biofilms colonize on inert medical devices, prosthesis, fibrosed tissues, sinus tracts as well as dead bones as in case of chronic osteomyelitis. Morganella morganii is not a common pathogen to produce biofilm. In this case report, we present a 56-year-old male patient with chronic osteomyelitis of right proximal tibia caused by biofilm producing strain of Morganella morganii, following trauma.}, } @article {pmid27503656, year = {2016}, author = {Pabst, B and Pitts, B and Lauchnor, E and Stewart, PS}, title = {Gel-Entrapped Staphylococcus aureus Bacteria as Models of Biofilm Infection Exhibit Growth in Dense Aggregates, Oxygen Limitation, Antibiotic Tolerance, and Heterogeneous Gene Expression.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {6294-6301}, pmid = {27503656}, issn = {1098-6596}, support = {R01 GM109452/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacteriological Techniques/*methods ; Biofilms/drug effects ; Drug Resistance, Bacterial/drug effects/genetics ; Gels ; Gene Expression Regulation, Bacterial/drug effects ; Microbial Sensitivity Tests ; Oxygen/metabolism ; Sepharose ; Staphylococcus aureus/*drug effects/*growth & development/physiology ; }, abstract = {An experimental model that mimicked the structure and characteristics of in vivo biofilm infections, such as those occurring in the lung or in dermal wounds where no biomaterial surface is present, was developed. In these infections, microbial biofilm forms as cell aggregates interspersed in a layer of mucus or host matrix material. This structure was modeled by filling glass capillary tubes with an agarose gel that had been seeded with Staphylococcus aureus bacteria and then incubating the gel biofilm in medium for up to 30 h. Confocal microscopy showed that the bacteria formed in discrete pockets distributed throughout the gel matrix. These aggregates enlarged over time and also developed a size gradient, with the clusters being larger near the nutrient- and oxygen-supplied interface and smaller at greater depths. Bacteria entrapped in gels for 24 h grew slowly (specific growth rate, 0.06 h(-1)) and were much less susceptible to oxacillin, minocycline, or ciprofloxacin than planktonic cells. Microelectrode measurements showed that the oxygen concentration decreased with depth into the gel biofilm, falling to values less than 3% of air saturation at depths of 500 μm. An anaerobiosis-responsive green fluorescent protein reporter gene for lactate dehydrogenase was induced in the region of the gel where the measured oxygen concentrations were low, confirming biologically relevant hypoxia. These results show that the gel biofilm model captures key features of biofilm infection in mucus or compromised tissue: formation of dense, distinct aggregates, reduced specific growth rates, local hypoxia, and antibiotic tolerance.}, } @article {pmid27503246, year = {2017}, author = {Molina-Henares, MA and Ramos-González, MI and Daddaoua, A and Fernández-Escamilla, AM and Espinosa-Urgel, M}, title = {FleQ of Pseudomonas putida KT2440 is a multimeric cyclic diguanylate binding protein that differentially regulates expression of biofilm matrix components.}, journal = {Research in microbiology}, volume = {168}, number = {1}, pages = {36-45}, doi = {10.1016/j.resmic.2016.07.005}, pmid = {27503246}, issn = {1769-7123}, mesh = {Adenosine Triphosphatases/genetics/*metabolism ; Artificial Gene Fusion ; Bacterial Proteins/genetics/*metabolism ; Binding Sites ; Biofilms/*growth & development ; Calorimetry ; Chromatography, Gel ; Consensus Sequence ; Cyclic GMP/*analogs & derivatives/metabolism ; DNA, Bacterial/metabolism ; DNA-Binding Proteins/genetics/*metabolism ; Electrophoretic Mobility Shift Assay ; Flagella/metabolism ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Polysaccharides, Bacterial/metabolism ; Promoter Regions, Genetic ; Protein Binding ; Protein Multimerization ; Pseudomonas putida/genetics/metabolism/*physiology ; Ultracentrifugation ; }, abstract = {The intracellular signal molecule cyclic di-GMP (c-di-GMP) is an important element in regulation of biofilm formation by bacteria. In Pseudomonas aeruginosa, FleQ functions as a c-di-GMP-dependent transcriptional regulator of expression of flagellar genes and the exopolysaccharide (EPS) Pel, a component of the biofilm extracellular matrix. In the plant-beneficial bacterium Pseudomonas putida KT2440, a mutation in fleQ reduces biofilm formation and colonization of plant surfaces. Using isothermal titration calorimetry and electrophoretic mobility shift assays, we show in this work that FleQ of P. putida interacts with c-di-GMP and directly binds the promoter regions of flagellar and EPS genes. Data obtained by analytical gel filtration and ultracentrifugation indicate that FleQ is in multiple oligomeric states in solution (dimers, tetramers and hexamers), which do not show altered equilibrium in the presence of c-di-GMP. DNA binding is independent of c-diGMP, although it is favored by the second messenger in the case of the promoter of the operon responsible for synthesis of the species-specific EPS Pea. Analysis of expression using transcriptional fusions showed an influence of FleQ upon two of the four EPS operons under regular growth conditions. Finally, a consensus sequence for promoter recognition by FleQ in P. putida is also proposed.}, } @article {pmid27503150, year = {2016}, author = {Joseph, R and Kaizerman, D and Herzog, IM and Hadar, M and Feldman, M and Fridman, M and Cohen, Y}, title = {Phosphonium pillar[5]arenes as a new class of efficient biofilm inhibitors: importance of charge cooperativity and the pillar platform.}, journal = {Chemical communications (Cambridge, England)}, volume = {52}, number = {70}, pages = {10656-10659}, doi = {10.1039/c6cc05170g}, pmid = {27503150}, issn = {1364-548X}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Calixarenes ; Enterococcus faecalis/*drug effects/physiology ; Gram-Positive Bacterial Infections/drug therapy ; Humans ; Organophosphorus Compounds/chemistry/*pharmacology ; Quaternary Ammonium Compounds/chemistry/*pharmacology ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Biofilm formation, which frequently occurs in microbial infections and often reduces the efficacy of antibiotics, also perturbs many industrial and domestic processes. We found that a new class of water soluble pillar[5]arenes bearing phosphonium moieties (1, 2) and their respective ammonium analogues (3, 4) inhibit biofilm formation with IC50 values in the range of 0.67-1.66 μM. These compounds have no antimicrobial activity, do not damage red blood cell membranes, and do not affect mammalian cell viability in culture. Comparison of the antibiofilm activities of the phosphonium-decorated pillar[5]arene derivatives 1 and 2 with their respective ammonium counterparts 3 and 4 and their monomers 5 and 6, demonstrate that while positive charges, charge cooperativity and the pillararene platform are essential for the observed antibiofilm activity the nature of the charges is not.}, } @article {pmid27502022, year = {2016}, author = {Yang, Y and Zhang, X and Huang, W and Yin, Y}, title = {SCCmec-associated psm-mec mRNA promotes Staphylococcus epidermidis biofilm formation.}, journal = {Antonie van Leeuwenhoek}, volume = {109}, number = {10}, pages = {1403-1415}, doi = {10.1007/s10482-016-0741-2}, pmid = {27502022}, issn = {1572-9699}, mesh = {*Biofilms ; DNA, Bacterial ; DNA, Complementary ; Gene Knockout Techniques ; *Genes, Bacterial ; Humans ; Methicillin Resistance ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Staphylococcus epidermidis/*genetics/growth & development/isolation & purification ; }, abstract = {Biofilm formation is considered the major pathogenic mechanism of Staphylococcus epidermidis-associated nosocomial infections. Reports have shown that SCCmec-associated psm-mec regulated methicillin-resistant Staphylococcus aureus virulence and biofilm formation. However, the role of psm-mec in S. epidermidis remains unclear. To this purpose, we analysed 165 clinical isolates of S. epidermidis to study the distribution, mutation and expression of psm-mec and the relationship between this gene and biofilm formation. Next, we constructed three psm-mec deletion mutants, one psm-mec transgene expression strain (p221) and two psm-mec point mutant strains (pM, pAG) to explore its effects on S. epidermidis biofilm formation. Then, the amount of biofilm formation, extracellular DNA (eDNA) and Triton X-100-induced autolysis of the constructed strains was measured. Results of psm-mec deletion and transgene expression showed that the gene regulated S. epidermidis biofilm formation. Compared with the control strains, the ability to form biofilm, Triton X-100-induced autolysis and the amount of eDNA increased in the p221 strain and the two psm-mec mutants pM and pAG expressed psm-mec mRNA without its protein, whereas no differences were observed among the three constructed strains, illustrating that psm-mec mRNA promoted S. epidermidis biofilm formation through up-regulation of bacterial autolysis and the release of eDNA. Our results reveal that acquisition of psm-mec promotes S. epidermidis biofilm formation.}, } @article {pmid27501984, year = {2016}, author = {Rowe, SE and Campbell, C and Lowry, C and O'Donnell, ST and Olson, ME and Lindgren, JK and Waters, EM and Fey, PD and O'Gara, JP}, title = {AraC-Type Regulator Rbf Controls the Staphylococcus epidermidis Biofilm Phenotype by Negatively Regulating the icaADBC Repressor SarR.}, journal = {Journal of bacteriology}, volume = {198}, number = {21}, pages = {2914-2924}, pmid = {27501984}, issn = {1098-5530}, support = {R01 AI049311/AI/NIAID NIH HHS/United States ; }, mesh = {Amidohydrolases/genetics/*metabolism ; *Biofilms ; Down-Regulation ; *Gene Expression Regulation, Bacterial ; *Operon ; Phenotype ; Polysaccharides, Bacterial/genetics/*metabolism ; Promoter Regions, Genetic ; Repressor Proteins/*genetics/metabolism ; Staphylococcus epidermidis/genetics/*physiology ; Transcription Factors/genetics/*metabolism ; }, abstract = {UNLABELLED: Regulation of icaADBC-encoded polysaccharide intercellular adhesin (PIA)/poly-N-acetylglucosasmine (PNAG) production in staphylococci plays an important role in biofilm-associated medical-device-related infections. Here, we report that the AraC-type transcriptional regulator Rbf activates icaADBC operon transcription and PIA production in Staphylococcus epidermidis Purified recombinant Rbf did not bind to the ica operon promoter region in electrophoretic mobility shift assays (EMSAs), indicating that Rbf regulates ica transcription indirectly. To identify the putative transcription factor(s) involved in Rbf-mediated icaADBC regulation, the ability of recombinant Rbf to interact with the promoter sequences of known icaADBC regulators was investigated. Recombinant Rbf bound to the sarR promoter and not the sarX, sarA, sarZ, spx, and srrA promoters. Reverse transcription (RT)-PCR demonstrated that Rbf acts as a repressor of sarR transcription. PIA expression and biofilm production were restored to wild-type levels in an rbf sarR double mutant grown in brain heart infusion (BHI) medium supplemented with NaCl, which is known to activate the ica locus, but not in BHI medium alone. RT-PCR further demonstrated that although Rbf does not bind the sarX promoter, it nevertheless exerted a negative effect on sarX expression. Apparently, direct downregulation of the SarR repressor by Rbf has a dominant effect over indirect repression of the SarX activator by Rbf in the control of S. epidermidis PIA production and biofilm formation.

IMPORTANCE: The importance of Staphylococcus epidermidis as an opportunistic pathogen in hospital patients with implanted medical devices derives largely from its capacity to form biofilm. Expression of the icaADBC-encoded extracellular polysaccharide is the predominant biofilm mechanism in S. epidermidis clinical isolates and is tightly regulated. Here, we report that the transcriptional regulator Rbf promotes icaADBC expression by negatively regulating expression of sarR, which encodes an ica operon repressor. Furthermore, Rbf indirectly represses the ica operon activator, SarX. The data reveal complicated interplay between Rbf and two Sar family proteins in fine-tuning regulation of the biofilm phenotype and indicate that in the hierarchy of biofilm regulators, IcaR is dominant over the Rbf-SarR-SarX axis.}, } @article {pmid27501424, year = {2016}, author = {Urzì, C and De Leo, F and Krakova, L and Pangallo, D and Bruno, L}, title = {Effects of biocide treatments on the biofilm community in Domitilla's catacombs in Rome.}, journal = {The Science of the total environment}, volume = {572}, number = {}, pages = {252-262}, doi = {10.1016/j.scitotenv.2016.07.195}, pmid = {27501424}, issn = {1879-1026}, mesh = {Bacteria/classification ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Microbiota/*drug effects ; Quaternary Ammonium Compounds/*pharmacology ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Rome ; Thiazoles/*pharmacology ; }, abstract = {Different types of biofilms are widespread on lithic faces of the Catacombs of Domitilla (Rome, Italy) due to the favorable microclimatic conditions (temperature, high RH% and low irradiance). The biofilm, once established, becomes particularly dangerous due to the coverage of valuable surfaces causing spoilage, softening of materials and mineral precipitation. It is common practice to treat these surfaces with biocides in order to eradicate the microorganisms present. The aim of the present research was to compare the changes occurring to the microbial community present in the biofilm in one site of the Catacombs of Domitilla (CD15) before and after a biocide treatment (a mixture of quaternary ammonium compounds and octylisothiazolone, OIT), applied for a one month period. A multistep approach was followed, based on microscopy, cultural methods and molecular techniques (f-ITS and 16S rDNA sequencing), for the phenotypic and genetic analysis of the culturable microbial population. Our results highlighted that the biocide treatments had little effect against cyanobacteria, while the bacterial population increased in numbers but changed drastically in terms of diversity. In fact, some bacteria proliferate at the expense of the organic matter released by dead microorganisms as demonstrated by laboratory tests. Further, our data describe how the microbial interaction can have different responses depending on the favorable conditions for one kind of microorganism in respect to the others. This study exemplifies the real risks of applying biocide treatments on complex microbial communities and pinpoints the necessity of subjecting treatments to monitoring and reassessment. Moreover, the work showed the potential of bacteria isolated after the treatment for use, under controlled conditions, in combatting unwanted microbial growth in that they possess a positive tropism toward stressed microorganisms and high hydrolytic enzymatic activity against cell components (e.g. cellulose, chitin and pectin). A tentative protocol is proposed.}, } @article {pmid27501265, year = {2016}, author = {Plotkin, BJ and Sigar, IM and Tiwari, V and Halkyard, S}, title = {Determination of Biofilm Initiation on Virus-infected Cells by Bacteria and Fungi.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {113}, pages = {}, pmid = {27501265}, issn = {1940-087X}, mesh = {Bacteria ; *Biofilms ; Candida albicans ; Staphylococcus aureus ; }, abstract = {The study of polymicrobial interactions across the taxonomic kingdoms that include fungi, bacteria and virus have not been previously examined with respect to how viral members of the microbiome affect subsequent microbe interactions with these virus-infected host cells. The co-habitation of virus with bacteria and fungi is principally present on the mucosal surfaces of the oral cavity and genital tract. Mucosal cells, particularly those with persistent chronic or persistent latent viral infections, could have a significant impact on members of the microbiome through virus alteration in number and type of receptors expressed. Modification in host cell membrane architecture would result in altered ability of subsequent members of the normal flora and opportunistic pathogens to initiate the first step in biofilm formation, i.e., adherence. This study describes a method for quantitation and visual examination of HSV's effect on the initiation of biofilm formation (adherence) of S. aureus and C. albicans.}, } @article {pmid27500604, year = {2016}, author = {Walker, M and Singh, A and Nazarali, A and Gibson, TW and Rousseau, J and Weese, JS}, title = {Evaluation of the Impact of Methicillin-Resistant Staphylococcus pseudintermedius Biofilm Formation on Antimicrobial Susceptibility.}, journal = {Veterinary surgery : VS}, volume = {45}, number = {7}, pages = {968-971}, doi = {10.1111/vsu.12535}, pmid = {27500604}, issn = {1532-950X}, mesh = {Amikacin/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Canada ; Cefazolin/pharmacology ; Dog Diseases/drug therapy/*microbiology ; Dogs ; Enrofloxacin ; Fluoroquinolones/pharmacology ; Gentamicins/pharmacology ; Methicillin Resistance ; Plankton/*drug effects ; Staphylococcal Infections/drug therapy/microbiology/*veterinary ; Staphylococcus/*drug effects/*physiology ; United States ; }, abstract = {OBJECTIVE: To compare the minimum inhibitory concentration (MIC) of four antimicrobials in planktonic vs. biofilm-associated Staphylococcus pseudintermedius.

STUDY DESIGN: In vitro study.

SAMPLE POPULATION: 78 isolates from dogs colonized or infected with methicillin-resistant S. pseudintermedius (MRSP, n=39) or methicillin-susceptible S. pseudintermedius (MSSP, n=39).

METHODS: Agar dilution was used to determine the MIC of amikacin, cefazolin, enrofloxacin, and gentamicin for planktonic bacteria. A modified broth microdilution assay was used to assess the MIC of biofilm-associated bacteria.

RESULTS: MIC were significantly higher in biofilm-associated vs. planktonic bacteria for all antimicrobials; amikacin (median MIC: biofilm >2,000 μg/mL vs. planktonic 3 μg/mL, P<.0001), cefazolin (>1,000 vs. 0.5 μg/mL, P<.0001), enrofloxacin (>1,000 vs. 0.25 μg/mL, P<.0001), and gentamicin (>1,000 vs. 0.3 μg/mL, P<.001). For all antimicrobials, there were significant differences in planktonic MIC for MRSP and MSSP (all P<.0001) but no differences between biofilm MIC for MRSP and MSSP (P=.08-1.0).

CONCLUSION: The MIC for biofilm-associated S. pseudintermedius are significantly higher than for planktonic bacteria. Standard methods for determining MIC are not appropriate for biofilm-associated infections. This must be considered when determining treatment regimens for infections that potentially involve biofilms, and further study of methods to control biofilm-associated infections is needed.}, } @article {pmid27498700, year = {2016}, author = {Kakade, P and Sadhale, P and Sanyal, K and Nagaraja, V}, title = {ZCF32, a fungus specific Zn(II)2 Cys6 transcription factor, is a repressor of the biofilm development in the human pathogen Candida albicans.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {31124}, pmid = {27498700}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Candida albicans/*physiology ; Fungal Proteins/genetics/*metabolism ; Humans ; Transcription Factors/genetics/*metabolism ; }, abstract = {As a human fungal pathogen, Candida albicans can cause a wide variety of disease conditions ranging from superficial to systemic infections. Many of these infections are caused by an inherent ability of the pathogen to form biofilms on medical devices resulting in high mortality. Biofilms formed by C. albicans are a complex consortium of yeast and hyphal cells embedded in an extracellular matrix and are regulated by a network of transcription factors. Here, we report the role of a novel Zn(II)2-Cys6 binuclear cluster transcription factor, ZCF32, in the regulation of biofilm formation. Global transcriptome analysis reveals that biofilm development is the most altered pathway in the zcf32 null mutant. To delineate the functional correlation between ZCF32 and biofilm development, we determined the set of genes directly regulated by Zcf32. Our data suggests that Zcf32 regulates biofilm formation by repressing the expression of adhesins, chitinases and a significant number of other GPI-anchored proteins. We establish that there is the lesser recruitment of Zcf32 on the promoters of biofilm genes in biofilm condition compared to the planktonic mode of growth. Taking together, we propose that the transcription factor ZCF32 negatively regulates biofilm development in C. albicans.}, } @article {pmid27497588, year = {2017}, author = {Beloin, C and Fernández-Hidalgo, N and Lebeaux, D}, title = {Understanding biofilm formation in intravascular device-related infections.}, journal = {Intensive care medicine}, volume = {43}, number = {3}, pages = {443-446}, pmid = {27497588}, issn = {1432-1238}, mesh = {Anti-Infective Agents, Local/*therapeutic use ; *Biofilms ; Catheters, Indwelling/*adverse effects ; Critical Care ; *Cross Infection/etiology/microbiology/prevention & control ; Disinfectants/*therapeutic use ; Humans ; Hygiene ; Intensive Care Units/standards ; }, } @article {pmid27497405, year = {2016}, author = {Dirain, CO and Silva, RC and Antonelli, PJ}, title = {Prevention of biofilm formation by polyquaternary polymer.}, journal = {International journal of pediatric otorhinolaryngology}, volume = {88}, number = {}, pages = {157-162}, doi = {10.1016/j.ijporl.2016.07.004}, pmid = {27497405}, issn = {1872-8464}, mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Humans ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Polyethylenes/*pharmacology ; Polymers/*pharmacology ; Polyurethanes ; Prospective Studies ; Prostheses and Implants ; Prosthesis-Related Infections/*prevention & control ; Pseudomonas aeruginosa/*drug effects ; Quaternary Ammonium Compounds/*pharmacology ; Staphylococcus aureus/*drug effects ; }, abstract = {OBJECTIVE: Biofilm formation has been linked to device-associated infections in otolaryngology. This study was conducted to determine if a microbicidal polyquaternary polymer, poly diallyl-dimethylammonium chloride (pDADMAC) could prevent biofilm development by pathogens that commonly cause implant infections, Staphylococcus aureus and Pseudomonas aeruginosa.

METHODS AND MATERIALS: This study was prospective and controlled in vitro microbiological study. Polyurethane tubes (20 per treatment) with and without a polyquaternary polymer coating were briefly exposed to plasma or saline, then to S. aureus or P. aeruginosa. Polyurethane tubes were incubated in growth media. After 4 days, antibiotics were added to kill planktonic bacteria. S. aureus or P. aeruginosa bacterial counts and scanning electron microscopy (SEM) were performed.

RESULTS: S. aureus biofilm counts were reduced by 8 logs on tubes with polyquaternary polymer coating compared to the control tubes, either with plasma (3.67E+01 ± 7.30E+01 vs 1.08E+09 ± 4.81E+08; P < 0.0001) or without plasma (3.70E+00 ± 1.10E+01 vs 6.50E+08 ± 2.79E+08; P < 0.0001). P. aeruginosa biofilm formation was also reduced on tubes with polyquaternary polymer, either with plasma (2.90E+07 ± 1.71E+07 vs 9.16E+08 ± 4.43E+08; P < 0.0001) or without plasma (2.50E+07 ± 9.54E+06 vs 3.35E+08 ± 2.18E+08; P < 0.001), but the reduction was only 1 log. On control tubes, plasma promoted S. aureus (1.08E+09 ± 4.81E+08 vs 6.05E+08 ± 2.79E+08; P < 0.0001) and P. aeruginosa (9.16E+08 ± 4.43E+08 vs 3.35E+08 ± 2.18E+08; P < 0.0001) bacterial counts but not on the tubes coated with polyquaternary polymer.

CONCLUSIONS: Incorporation of the microbicidal polyquaternary polymer, pDADMAC, into polyurethane dramatically inhibits S. aureus biofilm formation. Further research is warranted to evaluate the efficacy and safety of this technology in otolaryngologic implants.}, } @article {pmid27497060, year = {2016}, author = {Dutta, A and Bhattacharyya, S and Kundu, A and Dutta, D and Das, AK}, title = {Macroscopic amyloid fiber formation by staphylococcal biofilm associated SuhB protein.}, journal = {Biophysical chemistry}, volume = {217}, number = {}, pages = {32-41}, doi = {10.1016/j.bpc.2016.07.006}, pmid = {27497060}, issn = {1873-4200}, mesh = {Amyloid/*biosynthesis/chemistry ; *Biofilms ; Phosphoric Monoester Hydrolases/*metabolism ; Polysaccharides, Bacterial/metabolism ; Staphylococcus aureus/*chemistry/enzymology/metabolism ; }, abstract = {Staphylococcus aureus is a commensal and opportunistic pathogen that causes lethal infections. Biofilm forming ability of S. aureus enhances its virulence since biofilm provides the bacteria protective shield against antibiotics and host immunity. Polysaccharide independent biofilm formation by several virulent S. aureus strains have been identified recently, where protein components substitute polysaccharide intercellular adhesin (PIA) involved in bacterial cell attachment. The suhB gene has been reported to be essential in staphylococcal PIA-independent biofilm formation. Overexpression of staphylococcal SuhB (SasuhB) in E. coli produces extracellular macroscopic fibers made of recombinant SaSuhB protein. The amyloidic nature of the fiber is evaluated by high resolution electron microscopy, X-ray fiber diffraction and amyloid specific dyes, such as Congo red and thioflavin-T binding assay. The fibers appear to be sticky in nature and bind a large number of bacterial cells. The results suggest the possible role of SaSuhB-fibers as a structural component as well as an adhesin in biofilm matrix.}, } @article {pmid27496704, year = {2017}, author = {Bayramov, DF and Neff, JA}, title = {Beyond conventional antibiotics - New directions for combination products to combat biofilm.}, journal = {Advanced drug delivery reviews}, volume = {112}, number = {}, pages = {48-60}, pmid = {27496704}, issn = {1872-8294}, support = {R44 DK072560/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/pharmacology ; Anti-Infective Agents/*administration & dosage/*pharmacology ; Biofilms/*drug effects ; *Drug Delivery Systems ; Equipment and Supplies/*adverse effects ; Humans ; }, abstract = {Medical device related infections are a significant and growing source of morbidity and mortality. Biofilm formation is a common feature of medical device infections that is not effectively prevented or treated by systemic antibiotics. Antimicrobial medical device combination products provide a pathway for local delivery of antimicrobial therapeutics with the ability to achieve high local concentrations while minimizing systemic side effects. In this review, we present considerations for the design of local antimicrobial delivery systems, which can be facilitated by modeling local pharmacokinetics in the context of the target device application. In addition to the need for local delivery, a critical barrier to progress in the field is the need to incorporate agents effective against biofilm. This article aims to review key properties of antimicrobial peptides that make them well suited to meet the demands of the next generation of antimicrobial medical devices, including broad spectrum activity, rapid and biocidal mechanisms of action, and efficacy against biofilm.}, } @article {pmid27495263, year = {2016}, author = {Du, J and Singh, H and Yi, TH}, title = {Antibacterial, anti-biofilm and anticancer potentials of green synthesized silver nanoparticles using benzoin gum (Styrax benzoin) extract.}, journal = {Bioprocess and biosystems engineering}, volume = {39}, number = {12}, pages = {1923-1931}, doi = {10.1007/s00449-016-1666-x}, pmid = {27495263}, issn = {1615-7605}, mesh = {Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Antineoplastic Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/*physiology ; HeLa Cells ; Humans ; Metal Nanoparticles/*chemistry ; Mice ; Neoplasms/*drug therapy/metabolism ; Plant Extracts/*chemistry ; Silver/chemistry/*pharmacology ; Styrax/*chemistry ; }, abstract = {This study described a simple and green approach for the synthesis of silver nanoparticles (AgNPs) employing benzoin gum water extract as a reducing and capping agent and their applications. The AgNPs were characterized by ultraviolet-visible spectrophotometer, X-ray diffraction pattern, field emission transmission electron microscopy, dynamic light scattering, zeta potential and fourier transform infrared spectroscopy. The AgNPs showed promising antimicrobial activity against various pathogens (Gram-negative, Gram-positive and fungus) and possessed high free radical scavenging activity (104.5 ± 7.21 % at 1 mg/ml). In addition, the AgNPs exhibited strong cytotoxicity towards human cervical cancer and human lung cancer cells as compared to the normal mouse macrophage cells. Moreover, the AgNPs possessed anti-biofilm activity against Escherichia coli, and compatibility to human keratinocyte HaCaT cells, which suggests the use of dressing with the AgNPs in chronic wound treatment. Therefore, AgNPs synthesized by benzoin gum extract are comparatively green and may have broad spectrum potential application in biomedicine.}, } @article {pmid27494738, year = {2016}, author = {Pécastaings, S and Allombert, J and Lajoie, B and Doublet, P and Roques, C and Vianney, A}, title = {New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling.}, journal = {Biofouling}, volume = {32}, number = {8}, pages = {935-948}, doi = {10.1080/08927014.2016.1212988}, pmid = {27494738}, issn = {1029-2454}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/genetics/metabolism ; Escherichia coli Proteins/genetics/metabolism ; Legionella pneumophila/genetics/*growth & development/physiology ; Phosphoric Diester Hydrolases/genetics/metabolism ; Phosphorus-Oxygen Lyases/genetics/metabolism ; *Signal Transduction ; }, abstract = {The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species.}, } @article {pmid27494314, year = {2016}, author = {Zhou, Q and Zhang, L and Chen, J and Luo, Y and Zou, H and Sun, B}, title = {Enhanced stable long-term operation of biotrickling filters treating VOCs by low-dose ozonation and its affecting mechanism on biofilm.}, journal = {Chemosphere}, volume = {162}, number = {}, pages = {139-147}, doi = {10.1016/j.chemosphere.2016.07.072}, pmid = {27494314}, issn = {1879-1298}, mesh = {Air Pollutants/*analysis ; Biofilms/*drug effects/growth & development ; Biomass ; Bioreactors/*microbiology ; Filtration/methods ; Molecular Weight ; Ozone/chemistry/*pharmacology ; Volatile Organic Compounds/*analysis ; }, abstract = {For long-term operation of highly loaded biotrickling filters (BTFs), the prevention of excess biomass accumulation was essential for avoiding BTF failure. In this study, we proposed low-dose ozonation as a biomass control strategy to maintain high removal efficiencies of volatile organic compounds (VOCs) over extended operation of BTFs. To obtain an optimized biomass control strategy, the relative performance of five parallel BTFs receiving different ozone doses was determined, and the affecting mechanism of ozonation on biofilm was elucidated. Experimental results showed that the decline in ozone-free BTF performance began from day 150, which was correlated with excess biomass accumulation, abundant excretion of extracellular polymeric substances (EPS) and a decline in metabolic activity of biofilm over extended operation. Ozone of 5-10 mg m(-3) was effective in preventing excessive growth and uneven distribution of biomass, and eventually maintaining long-term stable operations. Ozone of over 20 mg m(-3) possibly inhibited microorganism growth severely, thereby deteriorating the elimination performance instead. Comparison of the biofilm EPS indicated that the presence of ozone reduce EPS contents to different extents, which was possibly beneficial for mass transfer and metabolic activity. Comparative community analysis showed that ozonation resulted in different microbial communities in the BTFs. Dyella was found to be the most abundant bacterial genera in all BTFs regardless of ozonation, indicating strong resistance to ozonation. Chryseobacterium and Burkholderia members were markedly enriched in the ozone-added biofilm, implying good adaptation to ozone presence. These findings provided an improved understanding of low-dose ozonation in maintaining a stable long-term operation of BTF.}, } @article {pmid27494102, year = {2016}, author = {Leix, C and Drewes, JE and Koch, K}, title = {The role of residual quantities of suspended sludge on nitrogen removal efficiency in a deammonifying moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {219}, number = {}, pages = {212-218}, doi = {10.1016/j.biortech.2016.07.134}, pmid = {27494102}, issn = {1873-2976}, mesh = {Bacteria ; *Biofilms ; Biomass ; Bioreactors/*microbiology ; Denitrification ; In Situ Hybridization, Fluorescence ; Nitrogen/chemistry ; Sewage/*microbiology ; }, abstract = {In a moving bed biofilm reactor (MBBR) system, the vast majority of biomass is immobilized as biofilm besides small amounts of suspension. In this study, the influence of the individual biomass components of a deammonifying MBBR, the biofilm on carriers (BC), residual suspended biomass (SB) with a volatile suspended solids concentration of 0.09±0.03g/L, and its combination (BC+SB) on nitrogen removal efficiency was investigated. While the performance was highest for BC+SB (0.42kgN/(m(3)·d)), it was reduced by a factor of 3.5 for BC solely. SB itself was only capable of nitrite accumulation. This suggests a high abundance of AOBs within suspension besides the coexistence of AOBs and anammox bacteria in the biofilm, which could be supported by results using fluorescence in situ hybridization(FISH). Thus, small amounts of suspended microorganisms can positively influence the deammonification's efficiency. If this fraction is partially washed out, the system recovers nevertheless within hours.}, } @article {pmid27493645, year = {2016}, author = {França, A and Pier, GB and Vilanova, M and Cerca, N}, title = {Transcriptomic Analysis of Staphylococcus epidermidis Biofilm-Released Cells upon Interaction with Human Blood Circulating Immune Cells and Soluble Factors.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1143}, pmid = {27493645}, issn = {1664-302X}, } @article {pmid27492542, year = {2016}, author = {Gouran, H and Gillespie, H and Nascimento, R and Chakraborty, S and Zaini, PA and Jacobson, A and Phinney, BS and Dolan, D and Durbin-Johnson, BP and Antonova, ES and Lindow, SE and Mellema, MS and Goulart, LR and Dandekar, AM}, title = {The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {31098}, pmid = {27492542}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Gene Expression Profiling ; Gene Knockout Techniques ; Locomotion ; Metalloendopeptidases/genetics/*metabolism ; Plant Diseases/*microbiology ; Proteomics ; Tobacco/microbiology ; Virulence ; Vitis/*microbiology ; Xylella/cytology/genetics/*pathogenicity/*physiology ; }, abstract = {Pierce's disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease "PrtA" that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa.}, } @article {pmid27492441, year = {2016}, author = {Chao, Y and Mao, Y and Yu, K and Zhang, T}, title = {Erratum to: Novel nitrifiers and comammox in a full-scale hybrid biofilm and activated sludge reactor revealed by metagenomic approach.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {18}, pages = {8239}, doi = {10.1007/s00253-016-7752-9}, pmid = {27492441}, issn = {1432-0614}, } @article {pmid27492011, year = {2016}, author = {Liu, Z and Gao, X and Wang, H and Fang, H and Yan, Y and Liu, L and Chen, R and Zhou, D and Yang, R and Han, Y}, title = {Plasmid pPCP1-derived sRNA HmsA promotes biofilm formation of Yersinia pestis.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {176}, pmid = {27492011}, issn = {1471-2180}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/analogs & derivatives/genetics/metabolism ; Phenotype ; Plasmids/genetics ; RNA, Bacterial/genetics/metabolism ; Real-Time Polymerase Chain Reaction ; Sequence Analysis, DNA ; Transcription Factors/genetics ; Yersinia pestis/enzymology/genetics/*physiology ; beta-Galactosidase/metabolism ; }, abstract = {BACKGROUND: The ability of Yersinia pestis to form a biofilm is an important characteristic in flea transmission of this pathogen. Y. pestis laterally acquired two plasmids (pPCP1and pMT1) and the ability to form biofilms when it evolved from Yersinia pseudotuberculosis. Small regulatory RNAs (sRNAs) are thought to play a crucial role in the processes of biofilm formation and pathogenesis.

RESULTS: A pPCP1-derived sRNA HmsA (also known as sR084) was found to contribute to the enhanced biofilm formation phenotype of Y. pestis. The concentration of c-di-GMP was significantly reduced upon deletion of the hmsA gene in Y. pestis. The abundance of mRNA transcripts determining exopolysaccharide production, crucial for biofilm formation, was measured by primer extension, RT-PCR and lacZ transcriptional fusion assays in the wild-type and hmsA mutant strains. HmsA positively regulated biofilm synthesis-associated genes (hmsHFRS, hmsT and hmsCDE), but had no regulatory effect on the biofilm degradation-associated gene hmsP. Interestingly, the recently identified biofilm activator sRNA, HmsB, was rapidly degraded in the hmsA deletion mutant. Two genes (rovM and rovA) functioning as biofilm regulators were also found to be regulated by HmsA, whose regulatory effects were consistent with the HmsA-mediated biofilm phenotype.

CONCLUSION: HmsA potentially functions as an activator of biofilm formation in Y. pestis, implying that sRNAs encoded on the laterally acquired plasmids might be involved in the chromosome-based regulatory networks implicated in Y. pestis-specific physiological processes.}, } @article {pmid27490283, year = {2016}, author = {Wang, Z and Morales-Acosta, MD and Li, S and Liu, W and Kanai, T and Liu, Y and Chen, YN and Walker, FJ and Ahn, CH and Leblanc, RM and Yan, EC}, title = {Correction: A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface.}, journal = {Chemical communications (Cambridge, England)}, volume = {52}, number = {68}, pages = {10440-10441}, doi = {10.1039/c6cc90360f}, pmid = {27490283}, issn = {1364-548X}, abstract = {Correction for 'A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface' by Zhuguang Wang et al., Chem. Commun., 2016, 52, 2956-2959.}, } @article {pmid27488009, year = {2016}, author = {Gupta, P and Chhibber, S and Harjai, K}, title = {Subinhibitory concentration of ciprofloxacin targets quorum sensing system of Pseudomonas aeruginosa causing inhibition of biofilm formation & reduction of virulence.}, journal = {The Indian journal of medical research}, volume = {143}, number = {5}, pages = {643-651}, pmid = {27488009}, issn = {0971-5916}, mesh = {Biofilms/drug effects/growth & development ; Ciprofloxacin/*pharmacology ; Dose-Response Relationship, Drug ; Humans ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Quorum Sensing/*drug effects/genetics ; Virulence/drug effects ; }, abstract = {BACKGROUND & OBJECTIVES: Biofilms formed by pseudomonas aeruginosa lead to persistent infections. Use of antibiotics for the treatment of biofilm induced infection poses a threat towards development of resistance. Therefore, the research is directed towards exploring the property of antibiotics which may alter the virulence of an organism besides altering its growth. The aim of this study was to evaluate the role of subinhibitory concentration of ciprofloxacin (CIP) in inhibiting biofilm formation and virulence of P. aeruginosa.

METHODS: Antibiofilm potential of subinhibitory concentration of CIP was evaluated in terms of log reduction, biofilm forming capacity and coverslip assay. P. aeruginosa isolates (grown in the presence and absence of sub-MIC of CIP) were also evaluated for inhibition in motility, virulence factor production and quorum sensing (QS) signal production.

RESULTS: Sub-minimum inhibitory concentration (sub-MIC) of CIP significantly reduced the motility of P. aeruginosa stand and strain and clinical isolates and affected biofilm forming capacity. Production of protease, elastase, siderophore, alginate, and rhamnolipid was also significantly reduced by CIP.

Reduction in virulence factors and biofilm formation was due to inhibition of QS mechanism which was indicated by reduced production of QS signal molecules by P. aeruginosa in presence of subinhibitory concentration of CIP.}, } @article {pmid27486827, year = {2016}, author = {Schrekker, CM and Sokolovicz, YC and Raucci, MG and Selukar, BS and Klitzke, JS and Lopes, W and Leal, CA and de Souza, IO and Galland, GB and Dos Santos, JH and Mauler, RS and Kol, M and Dagorne, S and Ambrosio, L and Teixeira, ML and Morais, J and Landers, R and Fuentefria, AM and Schrekker, HS}, title = {Multitask Imidazolium Salt Additives for Innovative Poly(l-lactide) Biomaterials: Morphology Control, Candida spp. Biofilm Inhibition, Human Mesenchymal Stem Cell Biocompatibility, and Skin Tolerance.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {33}, pages = {21163-21176}, doi = {10.1021/acsami.6b06005}, pmid = {27486827}, issn = {1944-8252}, mesh = {Animals ; Antifungal Agents ; Biocompatible Materials ; Biofilms ; Candida ; Humans ; *Mesenchymal Stem Cells ; Polyesters ; Skin ; Swine ; }, abstract = {Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly(l-lactide) films with different imidazolium salt (1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS)) contents were prepared, using the solvent casting process. Poly(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts C16MImCl and C16MImMeS presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices.}, } @article {pmid27486437, year = {2016}, author = {Prada-López, I and Quintas, V and Vilaboa, C and Suárez-Quintanilla, D and Tomás, I}, title = {Devices for In situ Development of Non-disturbed Oral Biofilm. A Systematic Review.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1055}, pmid = {27486437}, issn = {1664-302X}, abstract = {OBJECTIVE: The aim of this review was to assess the types of devices used for in situ development of oral biofilm analyzed microbiologically.

MATERIALS AND METHODS: A systematic search of the literature was conducted to identify all in situ studies of oral biofilm which used an oral device; the Ovid MEDLINE and EMBASE databases complemented with manual search were used. Specific devices used to microbiologically analyze oral biofilm in adults were included. After reading of the selected full texts, devices were identified and classified according to the oral cavity zone and manufacturing material. The "ideal" characteristics were analyzed in every group.

RESULTS: The search provided 787 abstracts, of which 111 papers were included. The devices used in these studies were classified as palatal, lingual or buccal. The last group was sub-classified in six groups based on the material of the device. Considering the analyzed characteristics, the thermoplastic devices and the Intraoral Device of Overlaid Disk-holding Splints (IDODS) presented more advantages than limitations.

CONCLUSIONS: Buccal devices were the most commonly used for the study of in situ biofilm. The majority of buccal devices seemed to slightly affect the volunteer's comfort, the IDODS being the closest to the "ideal" model.

CLINICAL RELEVANCE: New devices for in situ oral biofilm microbiological studies should take into account the possible effect of their design on the volunteer's comfort and biofilm formation.}, } @article {pmid27485639, year = {2016}, author = {Reichhardt, C and Stevens, DA and Cegelski, L}, title = {Fungal biofilm composition and opportunities in drug discovery.}, journal = {Future medicinal chemistry}, volume = {8}, number = {12}, pages = {1455-1468}, doi = {10.4155/fmc-2016-0049}, pmid = {27485639}, issn = {1756-8927}, mesh = {Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; *Drug Discovery ; Extracellular Matrix/chemistry/drug effects/metabolism ; Fungi/*drug effects/growth & development/immunology/*metabolism ; Humans ; Microbial Sensitivity Tests ; Molecular Structure ; Mycoses/*drug therapy/immunology/*microbiology ; }, abstract = {Biofilm infections are exceptionally recalcitrant to antimicrobial treatment or clearance by host immune responses. Within biofilms, microbes form adherent multicellular communities that are embedded in an extracellular matrix. Many prescribed antifungal drugs are not effective against biofilm infections owing to several protective factors including poor diffusion of drugs through biofilms as well as specific drug-matrix interactions. Despite the key roles that biofilms play in infections, there is little quantitative information about their composition and structural complexity because of the analytical challenge of studying these dense networks using traditional techniques. Within this review, recent work to elucidate fungal biofilm composition is discussed, with particular attention given to the challenges of annotation and quantification of matrix composition.}, } @article {pmid27485403, year = {2016}, author = {Wang, X and Zhou, L and Lu, L and Lobo, FL and Li, N and Wang, H and Park, J and Ren, ZJ}, title = {Alternating Current Influences Anaerobic Electroactive Biofilm Activity.}, journal = {Environmental science & technology}, volume = {50}, number = {17}, pages = {9169-9176}, doi = {10.1021/acs.est.6b00813}, pmid = {27485403}, issn = {1520-5851}, mesh = {Bioelectric Energy Sources ; *Biofilms ; Electricity ; Electrodes ; Electron Transport ; *Geobacter ; }, abstract = {Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network. Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology.}, } @article {pmid27485396, year = {2016}, author = {Swan, JS and Deasy, EC and Boyle, MA and Russell, RJ and O'Donnell, MJ and Coleman, DC}, title = {Elimination of biofilm and microbial contamination reservoirs in hospital washbasin U-bends by automated cleaning and disinfection with electrochemically activated solutions.}, journal = {The Journal of hospital infection}, volume = {94}, number = {2}, pages = {169-174}, doi = {10.1016/j.jhin.2016.07.007}, pmid = {27485396}, issn = {1532-2939}, mesh = {Automation/methods ; Bacteria/*drug effects ; Bacterial Load ; Biofilms/*drug effects ; Disinfectants/*pharmacology ; Disinfection/*methods ; Electrochemical Techniques/*methods ; Hospitals ; Hypochlorous Acid/pharmacology ; Sodium Hydroxide/pharmacology ; Solutions/*pharmacology ; *Water Microbiology ; }, abstract = {BACKGROUND: Washbasin U-bends are reservoirs of microbial contamination in healthcare environments. U-Bends are constantly full of water and harbour microbial biofilm.

AIM: To develop an effective automated cleaning and disinfection system for U-bends using two solutions generated by electrochemical activation of brine including the disinfectant anolyte (predominantly hypochlorous acid) and catholyte (predominantly sodium hydroxide) with detergent properties.

METHODS: Initially three washbasin U-bends were manually filled with catholyte followed by anolyte for 5min each once weekly for five weeks. A programmable system was then developed with one washbasin that automated this process. This U-bend had three cycles of 5min catholyte followed by 5min anolyte treatment per week for three months. Quantitative bacterial counts from treated and control U-bends were determined on blood agar (CBA), R2A, PAS, and PA agars following automated treatment and on CBA and R2A following manual treatment.

FINDINGS: The average bacterial density from untreated U-bends throughout the study was >1×10(5) cfu/swab on all media with Pseudomonas aeruginosa accounting for ∼50% of counts. Manual U-bend electrochemically activated (ECA) solution treatment reduced counts significantly (<100cfu/swab) (P<0.01 for CBA; P<0.005 for R2A). Similarly, counts from the automated ECA-treatment U-bend were significantly reduced with average counts for 35 cycles on CBA, R2A, PAS, and PA of 2.1±4.5 (P<0.0001), 13.1±30.1 (P<0.05), 0.7±2.8 (P<0.001), and 0 (P<0.05) cfu/swab, respectively. P. aeruginosa was eliminated from all treated U-bends.

CONCLUSION: Automated ECA treatment of washbasin U-bends consistently minimizes microbial contamination.}, } @article {pmid27483290, year = {2016}, author = {Tseng, SP and Hung, WC and Huang, CY and Lin, YS and Chan, MY and Lu, PL and Lin, L and Sheu, JH}, title = {5-Episinuleptolide Decreases the Expression of the Extracellular Matrix in Early Biofilm Formation of Multi-Drug Resistant Acinetobacter baumannii.}, journal = {Marine drugs}, volume = {14}, number = {8}, pages = {}, pmid = {27483290}, issn = {1660-3397}, mesh = {Acinetobacter Infections/microbiology/*prevention & control ; Acinetobacter baumannii/*drug effects/physiology/ultrastructure ; Animals ; Anthozoa/*chemistry ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biological Products/isolation & purification/pharmacology ; Cross Infection/microbiology/*prevention & control ; Diterpenes/chemistry/isolation & purification/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; Drug Synergism ; Equipment Contamination ; Extracellular Matrix/drug effects/ultrastructure ; Genes, Bacterial/drug effects ; Humans ; Levofloxacin/pharmacology ; Microscopy, Electron, Scanning ; beta-Glucans/metabolism ; }, abstract = {Nosocomial infections and increasing multi-drug resistance caused by Acinetobacter baumannii have been recognized as emerging problems worldwide. Moreover, A. baumannii is able to colonize various abiotic materials and medical devices, making it difficult to eradicate and leading to ventilator-associated pneumonia, and bacteremia. Development of novel molecules that inhibit bacterial biofilm formation may be an alternative prophylactic option for the treatment of biofilm-associated A. baumannii infections. Marine environments, which are unlike their terrestrial counterparts, harbor an abundant biodiversity of marine organisms that produce novel bioactive natural products with pharmaceutical potential. In this study, we identified 5-episinuleptolide, which was isolated from Sinularia leptoclados, as an inhibitor of biofilm formation in ATCC 19606 and three multi-drug resistant A. baumannii strains. In addition, the anti-biofilm activities of 5-episinuleptolide were observed for Gram-negative bacteria but not for Gram-positive bacteria, indicating that the inhibition mechanism of 5-episinuleptolide is effective against only Gram-negative bacteria. The mechanism of biofilm inhibition was demonstrated to correlate to decreased gene expression from the pgaABCD locus, which encodes the extracellular polysaccharide poly-β-(1,6)-N-acetylglucosamine (PNAG). Scanning electron microscopy (SEM) indicated that extracellular matrix of the biofilm was dramatically decreased by treatment with 5-episinuleptolide. Our study showed potentially synergistic activity of combination therapy with 5-episinuleptolide and levofloxacin against biofilm formation and biofilm cells. These data indicate that inhibition of biofilm formation via 5-episinuleptolide may represent another prophylactic option for solving the persistent problem of biofilm-associated A. baumannii infections.}, } @article {pmid27482513, year = {2016}, author = {Săndulescu, O}, title = {Managing sticky situations - anti-biofilm agents.}, journal = {Germs}, volume = {6}, number = {2}, pages = {49}, doi = {10.11599/germs.2016.1088}, pmid = {27482513}, issn = {2248-2997}, } @article {pmid27481285, year = {2016}, author = {Veach, AM and Stegen, JC and Brown, SP and Dodds, WK and Jumpponen, A}, title = {Spatial and successional dynamics of microbial biofilm communities in a grassland stream ecosystem.}, journal = {Molecular ecology}, volume = {25}, number = {18}, pages = {4674-4688}, doi = {10.1111/mec.13784}, pmid = {27481285}, issn = {1365-294X}, mesh = {Bacteria/*classification ; *Biofilms ; Chlorophyll ; Chlorophyll A ; *Grassland ; Kansas ; Phylogeny ; RNA, Ribosomal, 16S ; Rivers/*microbiology ; *Water Microbiology ; }, abstract = {Biofilms represent a metabolically active and structurally complex component of freshwater ecosystems. Ephemeral prairie streams are hydrologically harsh and prone to frequent perturbation. Elucidating both functional and structural community changes over time within prairie streams provides a general understanding of microbial responses to environmental disturbance. We examined microbial succession of biofilm communities at three sites in a third-order stream at Konza Prairie over a 2- to 64-day period. Microbial abundance (bacterial abundance, chlorophyll a concentrations) increased and never plateaued during the experiment. Net primary productivity (net balance of oxygen consumption and production) of the developing biofilms did not differ statistically from zero until 64 days suggesting a balance of the use of autochthonous and allochthonous energy sources until late succession. Bacterial communities (MiSeq analyses of the V4 region of 16S rRNA) established quickly. Bacterial richness, diversity and evenness were high after 2 days and increased over time. Several dominant bacterial phyla (Beta-, Alphaproteobacteria, Bacteroidetes, Gemmatimonadetes, Acidobacteria, Chloroflexi) and genera (Luteolibacter, Flavobacterium, Gemmatimonas, Hydrogenophaga) differed in relative abundance over space and time. Bacterial community composition differed across both space and successional time. Pairwise comparisons of phylogenetic turnover in bacterial community composition indicated that early-stage succession (≤16 days) was driven by stochastic processes, whereas later stages were driven by deterministic selection regardless of site. Our data suggest that microbial biofilms predictably develop both functionally and structurally indicating distinct successional trajectories of bacterial communities in this ecosystem.}, } @article {pmid27481242, year = {2016}, author = {Blanchette, KA and Shenoy, AT and Milner, J and Gilley, RP and McClure, E and Hinojosa, CA and Kumar, N and Daugherty, SC and Tallon, LJ and Ott, S and King, SJ and Ferreira, DM and Gordon, SB and Tettelin, H and Orihuela, CJ}, title = {Neuraminidase A-Exposed Galactose Promotes Streptococcus pneumoniae Biofilm Formation during Colonization.}, journal = {Infection and immunity}, volume = {84}, number = {10}, pages = {2922-2932}, pmid = {27481242}, issn = {1098-5522}, support = {T32 DE014318/DE/NIDCR NIH HHS/United States ; MR/M011569/1/MRC_/Medical Research Council/United Kingdom ; T32 AI007271/AI/NIAID NIH HHS/United States ; R01 AI114800/AI/NIAID NIH HHS/United States ; R01 AI078972/AI/NIAID NIH HHS/United States ; }, mesh = {Analysis of Variance ; Animals ; Biofilms/drug effects/*growth & development ; Carbohydrate Metabolism/*physiology ; Carbohydrates/*pharmacology ; Disease Models, Animal ; Epithelial Cells/metabolism ; Female ; Galactose/metabolism/*pharmacokinetics/pharmacology ; Humans ; Mice ; Mice, Inbred BALB C ; N-Acetylneuraminic Acid/metabolism ; Nasal Lavage Fluid/chemistry ; Nasal Septum/metabolism/microbiology ; Nasopharynx/metabolism/microbiology ; Neuraminidase/metabolism/*physiology ; Pneumococcal Infections/metabolism/*microbiology ; Streptococcus pneumoniae/drug effects/*physiology ; beta-Galactosidase/deficiency/metabolism ; }, abstract = {Streptococcus pneumoniae is an opportunistic pathogen that colonizes the nasopharynx. Herein we show that carbon availability is distinct between the nasopharynx and bloodstream of adult humans: glucose is absent from the nasopharynx, whereas galactose is abundant. We demonstrate that pneumococcal neuraminidase A (NanA), which cleaves terminal sialic acid residues from host glycoproteins, exposed galactose on the surface of septal epithelial cells, thereby increasing its availability during colonization. We observed that S. pneumoniae mutants deficient in NanA and β-galactosidase A (BgaA) failed to form biofilms in vivo despite normal biofilm-forming abilities in vitro Subsequently, we observed that glucose, sucrose, and fructose were inhibitory for biofilm formation, whereas galactose, lactose, and low concentrations of sialic acid were permissive. Together these findings suggested that the genes involved in biofilm formation were under some form of carbon catabolite repression (CCR), a regulatory network in which genes involved in the uptake and metabolism of less-preferred sugars are silenced during growth with preferred sugars. Supporting this notion, we observed that a mutant deficient in pyruvate oxidase, which converts pyruvate to acetyl-phosphate under non-CCR-inducing growth conditions, was unable to form biofilms. Subsequent comparative transcriptome sequencing (RNA-seq) analyses of planktonic and biofilm-grown pneumococci showed that metabolic pathways involving the conversion of pyruvate to acetyl-phosphate and subsequently leading to fatty acid biosynthesis were consistently upregulated during diverse biofilm growth conditions. We conclude that carbon availability in the nasopharynx impacts pneumococcal biofilm formation in vivo Additionally, biofilm formation involves metabolic pathways not previously appreciated to play an important role.}, } @article {pmid27479445, year = {2016}, author = {Liu, S and Gunawan, C and Barraud, N and Rice, SA and Harry, EJ and Amal, R}, title = {Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems.}, journal = {Environmental science & technology}, volume = {50}, number = {17}, pages = {8954-8976}, doi = {10.1021/acs.est.6b00835}, pmid = {27479445}, issn = {1520-5851}, mesh = {Bacteria/metabolism ; *Biofilms ; Disinfection ; Drinking Water/*chemistry ; RNA, Ribosomal, 16S/genetics ; Water Supply ; }, abstract = {In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for example, grow more-developed biofilms at a typical summer temperature of 22 °C compared to 12 °C in fall, and the opposite occurs for the pathogenic Vibrio cholerae. Recent investigations have found the formation of thinner yet denser biofilms under high and turbulent flow regimes of drinking water, in comparison to the more porous and loosely attached biofilms at low flow rates. Furthermore, in addition to the rather well-known tendency of significant biofilm growth on corrosion-prone metal pipes, research efforts also found leaching of growth-promoting organic compounds from the increasingly popular use of polymer-based pipes. Knowledge of the unique microbial members of drinking water biofilms and, importantly, the influence of water characteristics and operational conditions on their growth can be applied to optimize various operational parameters to minimize biofilm accumulation. More-detailed characterizations of the biofilm population size and structure are now feasible with fluorescence microscopy (epifluorescence and CLSM imaging with DNA, RNA, EPS, and protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, thorough identification of microbial fingerprints in drinking water biofilms is achievable with DNA sequencing techniques (the 16S rRNA gene-based identification), which have revealed a prevalence of previously undetected bacterial members. Technologies are now moving toward in situ monitoring of biomass growth in distribution networks, including the development of optical fibers capable of differentiating biomass from chemical deposits. Taken together, management of biofilm growth in water distribution systems requires an integrated approach, starting from the treatment of water prior to entering the networks to the potential implementation of "biofilm-limiting" operational conditions and, finally, ending with the careful selection of available technologies for biofilm monitoring and control. For the latter, conventional practices, including chlorine-chloramine disinfection, flushing of DWDS, nutrient removal, and emerging technologies are discussed with their associated challenges.}, } @article {pmid27479347, year = {2016}, author = {Prado, AM and Pereira, J and Henriques, B and Benfatti, CA and Magini, RS and López-López, J and Souza, JC}, title = {Biofilm Affecting the Mechanical Integrity of Implant-Abutment Joints.}, journal = {The International journal of prosthodontics}, volume = {29}, number = {4}, pages = {381-383}, doi = {10.11607/ijp.4759}, pmid = {27479347}, issn = {0893-2174}, mesh = {*Biofilms ; *Dental Abutments ; *Dental Implant-Abutment Design/methods ; *Dental Implants ; Microscopy, Electron, Scanning ; }, abstract = {PURPOSE: This in vitro study evaluated the effect of biofilms on abutment torque loss and wear of implant internal connection surfaces.

MATERIALS AND METHODS: Morse taper abutments were torqued to corresponding implants and then the implant-abutment assemblies were immersed in a biofilm medium for 72 hours. After detorque evaluation, the abutments were removed and the inner implant surfaces were observed via scanning electron microscopy and profilometry.

RESULTS: The removal torque values and the implant damaged areas decreased after contact with biofilms.

CONCLUSION: The lubricating effect of biofilms decreased the friction between contacting surfaces, negatively affecting the mechanical integrity of the implant-abutment connection.}, } @article {pmid27478696, year = {2016}, author = {Xu, D and Zhang, W and Zhang, B and Liao, C and Shao, Y}, title = {Characterization of a biofilm-forming Shigella flexneri phenotype due to deficiency in Hep biosynthesis.}, journal = {PeerJ}, volume = {4}, number = {}, pages = {e2178}, pmid = {27478696}, issn = {2167-8359}, abstract = {Deficiency in biosynthesis of inner core of lipopolysaccharide (LPS) rendered a characteristic biofilm-forming phenotype in E. coli. The pathological implications of this new phenotype in Shigella flexneri, a highly contagious enteric Gram-negative bacteria that is closely related to E. coli, were investigated in this study. The ΔrfaC (also referred as waaC) mutant, with incomplete inner core of LPS due to deficiency in Hep biosynthesis, was characteristic of strong biofilm formation ability and exhibited much more pronounced adhesiveness and invasiveness to human epithelial cells than the parental strain and other LPS mutants, which also showed distinct pattern of F-actin recruitment. Failure to cause keratoconjunctivitis and colonize in the intestine in guinea pigs revealed that the fitness gain on host adhesion resulted from biofilm formation is not sufficient to offset the loss of fitness on survivability caused by LPS deletion. Our study suggests a clear positive relationship between increased surface hydrophobicity and adhesiveness of Shigella flexneri, which should be put into consideration of virulence of Shigella, especially when therapeutic strategy targeting the core oligosaccharide (OS) is considered an alternative to deal with bacterial antibiotics-resistance.}, } @article {pmid27477857, year = {2016}, author = {Torresi, E and Fowler, SJ and Polesel, F and Bester, K and Andersen, HR and Smets, BF and Plósz, BG and Christensson, M}, title = {Biofilm Thickness Influences Biodiversity in Nitrifying MBBRs-Implications on Micropollutant Removal.}, journal = {Environmental science & technology}, volume = {50}, number = {17}, pages = {9279-9288}, doi = {10.1021/acs.est.6b02007}, pmid = {27477857}, issn = {1520-5851}, mesh = {Ammonia/metabolism ; Bacteria/metabolism ; Biodiversity ; *Biofilms ; *Bioreactors ; Nitrification ; RNA, Ribosomal, 16S/genetics ; }, abstract = {In biofilm systems for wastewater treatment (e.g., moving bed biofilms reactors-MBBRs) biofilm thickness is typically not under direct control. Nevertheless, biofilm thickness is likely to have a profound effect on the microbial diversity and activity, as a result of diffusion limitation and thus substrate penetration in the biofilm. In this study, we investigated the impact of biofilm thickness on nitrification and on the removal of more than 20 organic micropollutants in laboratory-scale nitrifying MBBRs. We used novel carriers (Z-carriers, AnoxKaldnes) that allowed controlling biofilm thickness at 50, 200, 300, 400, and 500 μm. The impact of biofilm thickness on microbial community was assessed via 16S rRNA gene amplicon sequencing and ammonia monooxygenase (amoA) abundance quantification through quantitative PCR (qPCR). Results from batch experiments and microbial analysis showed that (i) the thickest biofilm (500 μm) presented the highest specific biotransformation rate constants (kbio, L g(-1) d(-1)) for 14 out of 22 micropollutants; (ii) biofilm thickness positively associated with biodiversity, which was suggested as the main factor for the observed enhancement of kbio; (iii) the thinnest biofilm (50 μm) exhibited the highest nitrification rate (gN d(-1) g(-1)), amoA gene abundance and kbio values for some of the most recalcitrant micropollutants (i.e., diclofenac and targeted sulfonamides). Although thin biofilms favored nitrification activity and the removal of some micropollutants, treatment systems based on thicker biofilms should be considered to enhance the elimination of a broad spectrum of micropollutants.}, } @article {pmid27477508, year = {2016}, author = {El-Azizi, M and Farag, N and Khardori, N}, title = {Efficacy of selected biocides in the decontamination of common nosocomial bacterial pathogens in biofilm and planktonic forms.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {47}, number = {}, pages = {60-71}, doi = {10.1016/j.cimid.2016.06.002}, pmid = {27477508}, issn = {1878-1667}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/*drug effects ; Biofilms/*drug effects ; Burkholderia cepacia/drug effects ; Cross Infection/microbiology ; Decontamination/*methods ; Disinfectants/*pharmacology ; Enterococcus faecium/drug effects ; Humans ; Microbial Sensitivity Tests ; Peracetic Acid/*pharmacology ; Plankton/*drug effects ; Pseudomonas aeruginosa/drug effects ; }, abstract = {The efficacy and use of biocides to eliminate pathogens in the health care environment are based on their testing against planktonic bacteria. In the environment, bacteria exist in biofilms, as they do on medical devices, and as planktonic or viable non-culturable forms as well. This work aimed to evaluate the efficacy of four biocides against the biofilm and planktonic phases of nine common nosocomial bacteria. The bactericidal activity of the biocides against bacteria in the planktonic form was assessed using a broth microdilution technique. The killing activity of the biocides against biofilms was evaluated using cells grown on polyethylene tubes under a dynamic flow-cell system that was designed for biofilm growth. All biocides completely killed the planktonic bacteria at all concentrations; however, they did not eradicate the biofilms of the same pathogens. Our study highlights the need for an alternative strategy, one that utilizes chemicals that have been tested to disrupt or prevent biofilm growth, in order to enhance current disinfection practice.}, } @article {pmid27476204, year = {2016}, author = {Shumilova, E and Shelud'ko, AV and Filip'echeva, YA and Evstigneeva, SS and Ponomareva, EG and Petrova, LP and Katsy, EI}, title = {[Changes in Cell Surface Properties and Biofilm Formation Efficiency in Azospirillum brasilense Sp245 Mutants in the Putative Genes of Lipid Metabolism mmsB1 and fabG1].}, journal = {Mikrobiologiia}, volume = {85}, number = {2}, pages = {162-170}, pmid = {27476204}, issn = {0026-3656}, mesh = {Azospirillum brasilense/*physiology ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Lipid Metabolism/*physiology ; *Mutation ; }, abstract = {The previously obtained insertion mutants ofAzospirillum brasilense Sp245 in the genes mmsBl and fabG1 (strains SK039 and Sp245.1610, respectively) were characterized by impaired flagellation and motility. The putative products of expression of these genes are 3-hydroxyisobutyrate dehydrogenase and 3-oxoacyl-[acyl-carrier protein] reductase, respectively. In the present work, A. brasilense- Sp245 strains SK039 and Sp245.1610 were found to have differences in the content of 3-hydroxyhexadecanoic, hexadecanoic, 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, and nonadecanoic acids in their lipopolysaccharide prepa- rations, as well as in cell hydrophobicity and hemagglutination activity and dynamics of cell aggregation, in biomass amount, and in the relative content of lipopolysaccharide antigens in mature biofilms formed on hydrophilic or hydrophobic surfaces.}, } @article {pmid27475996, year = {2016}, author = {Giannelli, M and Landini, G and Materassi, F and Chellini, F and Antonelli, A and Tani, A and Zecchi-Orlandini, S and Rossolini, GM and Bani, D}, title = {The effects of diode laser on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide adherent to titanium oxide surface of dental implants. An in vitro study.}, journal = {Lasers in medical science}, volume = {31}, number = {8}, pages = {1613-1619}, pmid = {27475996}, issn = {1435-604X}, mesh = {Animals ; Bacterial Adhesion/*radiation effects ; Biofilms/*drug effects ; Decontamination ; Dental Implants/*microbiology ; Escherichia coli/*chemistry ; Fluorescence ; *Lasers, Semiconductor ; Lipopolysaccharides/*pharmacology ; Macrophage Activation/drug effects/radiation effects ; Mice ; Microbial Viability/radiation effects ; RAW 264.7 Cells ; Staphylococcus aureus/drug effects/*radiation effects/ultrastructure ; Surface Properties ; Titanium/*pharmacology ; }, abstract = {Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This in vitro study aims at providing the experimental basis for possible use of diode laser (λ 808 nm) in the treatment of peri-implantitis. Staphylococcus aureus biofilm was grown for 48 h on titanium discs with porous surface corresponding to the bone-implant interface and then irradiated with a diode laser (λ 808 nm) in noncontact mode with airflow cooling for 1 min using a Ø 600-μm fiber. Setting parameters were 2 W (400 J/cm[2]) for continuous wave mode; 22 μJ, 20 kHz, 7 μs (88 J/cm[2]) for pulsed wave mode. Bactericidal effect was evaluated using fluorescence microscopy and counting the residual colony-forming units. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, the titanium discs were coated with Escherichia coli lipopolysaccharide (LPS), laser-irradiated and seeded with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Diode laser irradiation in both continuous and pulsed modes induced a statistically significant reduction of viable bacteria and nitrite levels. These results indicate that in addition to its bactericidal effect laser irradiation can also inhibit LPS-induced macrophage activation and thus blunt the inflammatory response. The λ 808-nm diode laser emerges as a valuable tool for decontamination/detoxification of the titanium implant surface and may be used in the treatment of peri-implantitis.}, } @article {pmid27474962, year = {2016}, author = {Nielsen, KM and Kyneb, MH and Alstrup, AK and Jensen, JJ and Bender, D and Schønheyder, HC and Afzelius, P and Nielsen, OL and Jensen, SB}, title = {(68)Ga-labeled phage-display selected peptides as tracers for positron emission tomography imaging of Staphylococcus aureus biofilm-associated infections: Selection, radiolabelling and preliminary biological evaluation.}, journal = {Nuclear medicine and biology}, volume = {43}, number = {10}, pages = {593-605}, doi = {10.1016/j.nucmedbio.2016.07.002}, pmid = {27474962}, issn = {1872-9614}, mesh = {Amino Acid Sequence ; Animals ; *Biofilms ; Drug Stability ; Female ; *Gallium Radioisotopes ; Humans ; Mice ; Oligopeptides/*chemistry/pharmacokinetics ; *Peptide Library ; Positron-Emission Tomography/*methods ; Radioactive Tracers ; Radiochemistry ; Staphylococcal Infections/*diagnostic imaging ; Staphylococcus aureus/*physiology ; Swine ; }, abstract = {INTRODUCTION: Staphylococcus aureus is a major cause of skin and deep-sited infections, often associated with the formation of biofilms. Early diagnosis and initiated therapy is essential to prevent disease progression and to reduce complications that can be serious. Imaging techniques are helpful combining anatomical with functional data in order to describe and characterize site, extent and activity of the disease. The purpose of the study was to identify and (68)Ga-label peptides with affinity for S. aureus biofilm and evaluate their potential as bacteria-specific positron emission tomography (PET) imaging agents.

METHODS: Phage-displayed dodecapeptides were selected using an in vitro grown S. aureus biofilm as target. One cyclic (A8) and two linear (A9, A11) dodecapeptides were custom synthesized with 1,4,7,10-tetraazacyclododecane-N,N',N″,N‴-tetraacetic acid (DOTA) conjugated via a lysine linker (K), and for A11 also a glycine-serine-glycine spacer (GSG). The (68)Ga-labeling of A8-K-DOTA, A9-K-DOTA, and A11-GSGK-DOTA were optimized and in vitro bacterial binding was evaluated for (68)Ga-A9-K-DOTA and (68)Ga-A11-GSGK-DOTA. Stability of (68)Ga-A9-K-DOTA was studied in vitro in human serum, while the in vivo plasma stability was analyzed in mice and pigs. Additionally, the whole-body distribution kinetics of (68)Ga-A9-K-DOTA was measured in vivo by PET imaging of pigs and ex vivo in excised mice tissues.

RESULTS: The (68)Ga-A9-K-DOTA and (68)Ga-A11-GSGK-DOTA remained stable in product formulation, whereas (68)Ga-A8-K-DOTA was unstable. The S. aureus binding of (68)Ga-A11-GSGK-DOTA and (68)Ga-A9-K-DOTA was observed in vitro, though blocking of the binding was not possible by excess of cold peptide. The (68)Ga-A9-K-DOTA was degraded slowly in vitro, while the combined in vivo evaluation in pigs and mice showed a rapid blood clearance and renal excretion of the (68)Ga-A9-K-DOTA.

CONCLUSION: The preliminary in vitro and in vivo studies of the phage-display S. aureus biofilm-selected (68)Ga-A9-K-DOTA showed desirable features for a novel bacteria-specific imaging agent, despite of relative fast blood degradation in vivo.}, } @article {pmid27474923, year = {2016}, author = {Cascioferro, S and Maggio, B and Raffa, D and Raimondi, MV and Cusimano, MG and Schillaci, D and Manachini, B and Plescia, F and Daidone, G}, title = {Synthesis and biofilm formation reduction of pyrazole-4-carboxamide derivatives in some Staphylococcus aureus strains.}, journal = {European journal of medicinal chemistry}, volume = {123}, number = {}, pages = {58-68}, doi = {10.1016/j.ejmech.2016.07.030}, pmid = {27474923}, issn = {1768-3254}, mesh = {Animals ; Anti-Bacterial Agents/chemical synthesis/pharmacology ; Biofilms/*drug effects ; Hydrazines/chemical synthesis/*pharmacology ; Larva/drug effects ; Moths/microbiology ; Pyrazoles/chemical synthesis/*pharmacology ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects/physiology ; Structure-Activity Relationship ; Virulence/drug effects ; }, abstract = {The ability of several N-phenyl-1H-pyrazole-4-carboxamide derivatives and other pyrazoles opportunely modified at the positions 3, 4 and 5, to reduce the formation of the biofilm in some Staphylococcus aureus strains (ATCC 29213, ATCC 25923 and ATCC 6538) were investigated. All the tested compounds were able, although to a different extent, to reduce the biofilm formation of the three bacterial strains considered. Among these, the 1-(2,5-dichlorophenyl)-5-methyl-N-phenyl-1H-pyrazole-4-carboxamide 14 resulted as the best inhibitor of biofilm formation showing an IC50 ranging from 2.3 to 32 μM, against all the three strains of S. aureus. Compound 14 also shows a good protective effect in vivo by improving the survival of wax moth larva (Galleria mellonella) infected with S. aureus ATCC 29213. These findings indicate that 14d is a potential lead compound for the development of new anti-virulence agents against S. aureus infections.}, } @article {pmid27472954, year = {2016}, author = {Zhou, H and Liu, H and Weir, MD and Reynolds, MA and Zhang, K and Xu, HH}, title = {Three-dimensional biofilm properties on dental bonding agent with varying quaternary ammonium charge densities.}, journal = {Journal of dentistry}, volume = {53}, number = {}, pages = {73-81}, pmid = {27472954}, issn = {1879-176X}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {Ammonium Compounds ; Anti-Bacterial Agents ; *Biofilms ; Dental Bonding ; Dental Materials ; Resin Cements ; Streptococcus mutans ; }, abstract = {OBJECTIVES: Tooth-restoration interfaces are the weak link with secondary caries causing restoration failure. The objectives of this study were to develop an antimicrobial bonding agent with dimethylaminododecyl methacrylate (DMAHDM), and investigate the effects of quaternary amine charge density on three-dimensional (3D) biofilms on dental resin for the first time.

METHODS: DMAHDM was synthesized and incorporated into Scotchbond Multi-Purpose bonding agent at mass fractions of 0% (control), 2.5%, 5%, 7.5% and 10%. Streptococcus mutans bacteria were inoculated on the polymerized resin and cultured for two days to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live and dead biofilm volumes, and live bacteria percentage in 3D biofilm vs. distance from resin surface.

RESULTS: Charge density of the resin had a significant effect on the antibacterial efficacy (p<0.05). Biofilms on control resin had the greatest thicknesses. Biofilm thickness and live biofilm volume decreased with increasing surface charge density (p<0.05). There were significant variations in bacterial viability along the 3D biofilm thickness (p<0.05). At 2.5% and 5% DMAHDM, the bacterial inhibition was the greatest on or near the resin surface, and the killing effect decreased away from the resin surface. At 10% DMAHDM, the entire 3D biofilm was dead and the percentage of live bacteria was nearly 0% throughout the biofilm thickness.

CONCLUSIONS: Adding new antibacterial monomer DMAHDM into dental bonding agent yielded a strong antimicrobial activity, substantially decreasing the 3D biofilm thickness, live biofilm volume, and percentage of live bacteria on cross-sections through the biofilm thickness.

SIGNIFICANCE: Novel DMAHDM-containing bonding agent with capability of inhibiting 3D biofilms is promising for a wide range of dental restorative and preventive applications to inhibit biofilms at the tooth-restoration margins and prevent secondary caries.}, } @article {pmid27472563, year = {2016}, author = {Hinds, LM and Moser, EA and Eckert, G and Gregory, RL}, title = {Effect of Infant Formula on Streptococcus Mutans Biofilm Formation.}, journal = {The Journal of clinical pediatric dentistry}, volume = {40}, number = {3}, pages = {178-185}, doi = {10.17796/1053-4628-40.3.178}, pmid = {27472563}, issn = {1053-4628}, mesh = {Bacteriological Techniques ; Biofilms/*growth & development ; Chlorides/metabolism ; Coloring Agents ; Culture Media ; Ferric Compounds/metabolism ; Gentian Violet ; Humans ; Infant Formula/analysis/*microbiology ; Iron/analysis ; Lactose/metabolism ; Streptococcus mutans/*growth & development/metabolism ; Sucrose/metabolism ; }, abstract = {OBJECTIVE: This study investigated the effect that infant formula had on biofilm growth of Streptococcus mutans. Specifically, it compared biofilm growth in media containing lactose-based and sucrose-based formulas. It also analyzed biofilm formation with formulas of varying iron content. Biofilm growth was tested with the specific infant formula components sucrose, lactose, and ferric chloride. The study was designed to determine if these types of infant formulas and components affected S. mutans biofilm formation differently.

STUDY DESIGN: A 24-hour culture of S. mutans was treated with various concentrations of infant formula diluted in bacteriological media. To test for biofilm formation, S. mutans was cultured with and without the infant formula and formula components. The biofilms were washed, fixed, and stained with crystal violet. The absorbance was measured to evaluate biofilm growth and total absorbance.

RESULTS: Sucrose-based formulas provided significant increases in biofilm growth when compared to lactose-based formulas at two dilutions (1:5, 1:20). Similac Sensitive RS (sucrose-based) at most dilutions provided the most significant increase in biofilm growth when compared to the control. Sucrose tested as an individual component provided more of a significant increase on biofilm growth than lactose or iron when compared to the control. A low iron formula provided a significant increase in biofilm growth at one dilution (1:5) when compared to formula containing a normal iron content. There was no significant difference in biofilm growth when comparing high iron formula to normal iron formula or low iron formula. There was no significant difference when comparing Similac PM 60/40 (low iron formula) to Similac PM 60/40 with additional ferric chloride.

CONCLUSION: The results of this study demonstrated that sucrose-based formula provided more of a significant increase in biofilm growth compared to lactose-based formula. Sucrose alone provided a significant increase of biofilm growth at more dilutions when compared to the control than lactose and iron. The amount of iron in formula had a significant effect on biofilm formation only when comparing low iron formula to normal iron formula at the highest concentration (1:5). There was no significant difference in biofilm growth when iron was added to the low iron formula. The information obtained expands current knowledge regarding the influence of infant formula on the primary dentition and reinforces the importance of oral hygiene habits once the first tooth erupts.}, } @article {pmid27472386, year = {2016}, author = {Pemmaraju, SC and Padmapriya, K and Pruthi, PA and Prasad, R and Pruthi, V}, title = {Impact of oxidative and osmotic stresses on Candida albicans biofilm formation.}, journal = {Biofouling}, volume = {32}, number = {8}, pages = {897-909}, doi = {10.1080/08927014.2016.1212021}, pmid = {27472386}, issn = {1029-2454}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects/metabolism/pathogenicity/physiology ; Hydrogen Peroxide/*pharmacology ; Microbial Viability ; Osmotic Pressure ; Oxidation-Reduction ; Oxidative Stress/*drug effects ; Sodium Chloride/*pharmacology ; Virulence/drug effects ; Virulence Factors/metabolism ; }, abstract = {Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H2O2) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches.}, } @article {pmid27472312, year = {2016}, author = {Ikram, HM and Rasool, N and Zubair, M and Khan, KM and Abbas Chotana, G and Akhtar, MN and Abu, N and Alitheen, NB and Elgorban, AM and Rana, UA}, title = {Efficient Double Suzuki Cross-Coupling Reactions of 2,5-Dibromo-3-hexylthiophene: Anti-Tumor, Haemolytic, Anti-Thrombolytic and Biofilm Inhibition Studies.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {8}, pages = {}, pmid = {27472312}, issn = {1420-3049}, mesh = {Antineoplastic Agents/*chemical synthesis/chemistry/pharmacology ; Biofilms/*drug effects ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Fibrinolytic Agents/*chemical synthesis/chemistry/pharmacology ; Hemolytic Agents/*chemical synthesis/chemistry/pharmacology ; Humans ; MCF-7 Cells ; Microbial Sensitivity Tests ; Molecular Structure ; Thiophenes/*chemical synthesis/chemistry/pharmacology ; }, abstract = {The present study describes several novel 2,5-biaryl-3-hexylthiophene derivatives (3a-i) synthesized via a Pd(0)-catalyzed Suzuki cross-coupling reaction in moderate to good yields. The novel compounds were also analyzed for their anti-thrombolytic, haemolytic, and biofilm inhibition activities. In addition, the anti-tumor activity was also evaluated in vitro for newly-synthesized compounds, where 3-hexyl-2,5-bis(4-(methylthio)phenyl)thiophene exhibited the best anti-tumor activity against 4T1 cells with IC50 value of 16 μM. Moreover, 2,5-bis(4-methylphenyl)-3-hexylthiophene showed the highest activity against MCF-7 cells with an IC50 value of 26.2 μM. On the other hand, the compound 2,5-bis(4-chloropheny)-3-hexylthiophene exhibited excellent biofilm inhibition activity. Furthermore, the compound 2,5-bis(3-chloro-4-fluorophenyl)-3-hexylthiophene also exhibited better anti-thrombolytic and hemolytic activity results as compared to the other newly-synthesized compounds.}, } @article {pmid27471123, year = {2016}, author = {Rice, SA and Wuertz, S and Kjelleberg, S}, title = {Next-generation studies of microbial biofilm communities.}, journal = {Microbial biotechnology}, volume = {9}, number = {5}, pages = {677-680}, pmid = {27471123}, issn = {1751-7915}, mesh = {Biofilms/*growth & development ; *Microbial Consortia ; *Microbial Interactions ; }, abstract = {As we look into the future of microbial biofilm research, there is clearly an emerging focus on communities rather than populations. This represents an essential change in direction to more accurately understand how and why microorganisms assemble into communities, as well as the functional implications for such a life style. For example, current research studies shows that communities display emergent properties or functions that are not predicted from the individual single species populations, including elevated stress tolerance and resistance to antibiotics. Models for mixed species biofilms can be very simple, comprised only a handful of species or can be extremely species rich, with hundreds or thousands of species present. The future holds much promise for this area of research, where investigators will increasingly be able to resolve, at the molecular and biochemical levels, interspecies relationships and mechanisms of interaction. The outcome of these studies will greatly enhance our understanding of the ecological and evolutionary factors that drive community function in natural and engineered systems.}, } @article {pmid27468744, year = {2016}, author = {Zhao, L and Xu, G and Wang, Z and Xu, H}, title = {Body-size spectra of biofilm-dwelling protozoa and their seasonal shift in coastal ecosystems.}, journal = {European journal of protistology}, volume = {56}, number = {}, pages = {32-40}, doi = {10.1016/j.ejop.2016.07.003}, pmid = {27468744}, issn = {1618-0429}, mesh = {*Biofilms ; China ; *Ecosystem ; Environmental Monitoring ; Eukaryota/*cytology/*physiology ; Oceans and Seas ; *Seasons ; }, abstract = {Community-based assessment of protozoa is usually performed at a taxon-dependent resolution. As an inherent 'taxon-free' trait, however, body-size spectrum has proved to be a highly informative indicator to summarize the functional structure of a community in both community research and monitoring programs in aquatic ecosystems. To demonstrate the relationships between the taxon-free resolution of protozoan communities and water conditions, the body-size spectra of biofilm-dwelling protozoa and their seasonal shift and environmental drivers were explored based on an annual dataset collected monthly from coastal waters of the Yellow Sea, northern China. Body sizes were calculated in equivalent spherical diameter (ESD). Among a total of 8 body-size ranks, S2 (19-27μm), S3 (28-36μm), S4 (37-50μm) and S5 (53-71μm) were the top four levels in frequency of occurrence, while rank S1 (13-17μm), S2 and S4 were the dominant levels in abundance. These dominants showed a clear seasonal succession: S2/S4 (spring)→S2/S4 (summer)→S4 (autumn)→S2 (winter) in frequency of occurrence; S1 (spring)→S4 (summer)→S2 (autumn)→S1 (winter) in abundance. Bootstrapped average analysis showed a clear seasonal shift in body-size spectra of the protozoa during a 1-year cycle, and the best-matching analysis demonstrated that the temporal variations in frequency of occurrence and abundance were significantly correlated with water temperature, pH, dissolved oxygen (DO), alone or in combination with chemical oxygen demand (COD) and nutrients. Thus, the body-size spectra of biofilm-dwelling protozoa were seasonally shaped and might be used as a time and cost efficient bioindicator of water quality in marine ecosystems.}, } @article {pmid27468282, year = {2016}, author = {Weiland-Bräuer, N and Kisch, MJ and Pinnow, N and Liese, A and Schmitz, RA}, title = {Highly Effective Inhibition of Biofilm Formation by the First Metagenome-Derived AI-2 Quenching Enzyme.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1098}, pmid = {27468282}, issn = {1664-302X}, abstract = {Bacterial cell-cell communication (quorum sensing, QS) represents a fundamental process crucial for biofilm formation, pathogenicity, and virulence allowing coordinated, concerted actions of bacteria depending on their cell density. With the widespread appearance of antibiotic-resistance of biofilms, there is an increasing need for novel strategies to control harmful biofilms. One attractive and most likely effective approach is to target bacterial communication systems for novel drug design in biotechnological and medical applications. In this study, metagenomic large-insert libraries were constructed and screened for QS interfering activities (quorum quenching, QQ) using recently established reporter strains. Overall, 142 out of 46,400 metagenomic clones were identified to interfere with acyl-homoserine lactones (AHLs), 13 with autoinducer-2 (AI-2). Five cosmid clones with highest simultaneous interfering activities were further analyzed and the respective open reading frames conferring QQ activities identified. Those showed homologies to bacterial oxidoreductases, proteases, amidases and aminotransferases. Evaluating the ability of the respective purified QQ-proteins to prevent biofilm formation of several model systems demonstrated highest inhibitory effects of QQ-2 using the crystal violet biofilm assay. This was confirmed by heterologous expression of the respective QQ proteins in Klebsiella oxytoca M5a1 and monitoring biofilm formation in a continuous flow cell system. Moreover, QQ-2 chemically immobilized to the glass surface of the flow cell effectively inhibited biofilm formation of K. oxytoca as well as clinical K. pneumoniae isolates derived from patients with urinary tract infections. Indications were obtained by molecular and biochemical characterizations that QQ-2 represents an oxidoreductase most likely reducing the signaling molecules AHL and AI-2 to QS-inactive hydroxy-derivatives. Overall, we propose that the identified novel QQ-2 protein efficiently inhibits AI-2 modulated biofilm formation by modifying the signal molecule; and thus appears particularly attractive for medical and biotechnological applications.}, } @article {pmid27462729, year = {2016}, author = {Costa, A and Bertolotti, L and Brito, L and Civera, T}, title = {Biofilm Formation and Disinfectant Susceptibility of Persistent and Nonpersistent Listeria monocytogenes Isolates from Gorgonzola Cheese Processing Plants.}, journal = {Foodborne pathogens and disease}, volume = {13}, number = {11}, pages = {602-609}, doi = {10.1089/fpd.2016.2154}, pmid = {27462729}, issn = {1556-7125}, mesh = {Acetic Acid/pharmacology ; Bacterial Load/drug effects ; Biofilms/*drug effects/growth & development ; Cheese/*microbiology ; Citric Acid/pharmacology ; Coloring Agents/chemistry ; Dairying/*instrumentation ; Disinfectants/*pharmacology ; *Drug Resistance, Multiple, Bacterial ; *Equipment Contamination/prevention & control ; Food Contamination/prevention & control ; Gentian Violet/chemistry ; Hydrogen Peroxide/chemistry/pharmacology ; Hyphae/growth & development/metabolism ; Italy ; Listeria monocytogenes/*drug effects/growth & development/isolation & purification/physiology ; Microbial Viability/drug effects ; Penicillium/growth & development/metabolism ; Sanitation ; Spatio-Temporal Analysis ; Staining and Labeling ; Stainless Steel ; }, abstract = {The aim of this study was to investigate whether the biofilm-forming ability and/or the disinfectant susceptibility accounted for the persistence of Listeria monocytogenes in Gorgonzola cheese processing plants. For this purpose, a set of 16 L. monocytogenes isolates collected in the 2004-2007 period was analyzed, including 11 persistent isolates collected in different years, within the collection period, and displaying identical or highly correlated pulsotypes. The evaluation of biofilm-forming ability was assessed using crystal violet (CV) staining and the enumeration of viable cells on stainless steel coupons (SSC). Absorbance values obtained with CV staining for persistent and nonpersistent isolates were not significantly different (rm-ANOVA p > 0.05) and the cell counts from nonpersistent isolates showed to be higher compared with persistent isolates (rm-ANOVA p < 0.05). A simulation of disinfectant treatments was performed on spot inoculated coupons in clean and dirty conditions, according to EN 13697, and on biofilms on SSC, grown in nutrient-rich (dirty) and limiting (clean) conditions using acid acetic-hydrogen peroxide (P3) and acid citric-hydrogen peroxide (MS) commercial disinfectants. The treatment was considered effective when a 4 Log reduction in viable cell count was observed. The Log reductions of persistent and nonpersistent isolates, obtained with both the assays in clean and dirty conditions, were compared and no significant differences were detected (rm-ANOVA p > 0.05). A greater influence of organic matter on MS could explain why P3 was efficient in reducing to effective levels the majority of the isolates at the lowest concentration suggested by the manufacturer (0.2% [v/v]), while the same purpose required a higher concentration (1% [v/v]) of MS. In conclusion, our results demonstrate that the persistence of these isolates in Gorgonzola cheese processing plants was linked neither to the biofilm-forming ability nor to their susceptibility to hydrogen peroxide-based disinfectants; therefore, other factors should contribute to the persistent colonization of the dairies.}, } @article {pmid27460095, year = {2016}, author = {Singh, N and Patil, A and Prabhune, A and Goel, G}, title = {Inhibition of quorum-sensing-mediated biofilm formation in Cronobacter sakazakii strains.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {9}, pages = {1708-1714}, doi = {10.1099/mic.0.000342}, pmid = {27460095}, issn = {1465-2080}, mesh = {Biofilms/*drug effects ; Cronobacter sakazakii/*drug effects/physiology ; Drug Evaluation, Preclinical ; Plant Extracts/*pharmacology ; Plants/*chemistry ; Quorum Sensing/*drug effects ; }, abstract = {The present study investigated plant extracts for their anti-quorum-sensing (QS) potential to inhibit the biofilm formation in Cronobacter sakazakii strains. The bioassay based on loss of pigment production by Chromobacterium violaceum 026 and Agrobacterium tumefaciens NTL4(pZLR4) was used for initial screening of the extracts. Further, the effect of extracts on the inhibition of QS-mediated biofilm in C. sakazakii isolates was evaluated using standard crystal violet assay. The effect on biofilm texture was studied using SYTO9 staining and light and scanning electron microscopy. Among the tested extracts, Piper nigrum and Cinnamomum verum at 100 ppm resulted in 78 and 68 % reduction in the production of violacein as well as blue-green colour in both biosensor strains. A higher inhibitory activity (>50 %) on biofilm formation in C. sakazakii was observed for Pip. nigrum and Cin. verum, whereas the other extracts possessed moderate (25-50 %) and minimal (<25 %) inhibitory activities. Further, the fluorescent and scanning electron microscopic images indicated a major disruption in the architecture of biofilms of tested strains by Pip. nigrum. This study points to the possibility of using Pip. nigrum and Cin. verum as inhibitor of QS-mediated biofilm formation by C. sakazakii that could be further explored for novel bioactive molecules to limit the emerging infections of C. sakazakii.}, } @article {pmid27459270, year = {2017}, author = {Ahlstrand, T and Tuominen, H and Beklen, A and Torittu, A and Oscarsson, J and Sormunen, R and Pöllänen, MT and Permi, P and Ihalin, R}, title = {A novel intrinsically disordered outer membrane lipoprotein of Aggregatibacter actinomycetemcomitans binds various cytokines and plays a role in biofilm response to interleukin-1β and interleukin-8.}, journal = {Virulence}, volume = {8}, number = {2}, pages = {115-134}, pmid = {27459270}, issn = {2150-5608}, mesh = {Aggregatibacter actinomycetemcomitans/chemistry/immunology/*metabolism ; Bacterial Outer Membrane Proteins/chemistry/immunology/isolation & purification/*metabolism ; Biofilms/*growth & development ; Gingiva/microbiology ; Humans ; Interleukin-10/genetics/metabolism/pharmacology ; Interleukin-1beta/genetics/*metabolism/pharmacology ; Interleukin-8/genetics/*metabolism/pharmacology ; Intrinsically Disordered Proteins/chemistry/immunology/*metabolism ; Lipoproteins/immunology/metabolism ; Receptors, Interleukin-1/*metabolism ; Tumor Necrosis Factor-alpha/metabolism ; }, abstract = {Intrinsically disordered proteins (IDPs) do not have a well-defined and stable 3-dimensional fold. Some IDPs can function as either transient or permanent binders of other proteins and may interact with an array of ligands by adopting different conformations. A novel outer membrane lipoprotein, bacterial interleukin receptor I (BilRI) of the opportunistic oral pathogen Aggregatibacter actinomycetemcomitans binds a key gatekeeper proinflammatory cytokine interleukin (IL)-1β. Because the amino acid sequence of the novel lipoprotein resembles that of fibrinogen binder A of Haemophilus ducreyi, BilRI could have the potential to bind other proteins, such as host matrix proteins. However, from the tested host matrix proteins, BilRI interacted with neither collagen nor fibrinogen. Instead, the recombinant non-lipidated BilRI, which was intrinsically disordered, bound various pro/anti-inflammatory cytokines, such as IL-8, tumor necrosis factor (TNF)-α, interferon (IFN)-γ and IL-10. Moreover, BilRI played a role in the in vitro sensing of IL-1β and IL-8 because low concentrations of cytokines did not decrease the amount of extracellular DNA in the matrix of bilRI[-] mutant biofilm as they did in the matrix of wild-type biofilm when the biofilms were exposed to recombinant cytokines for 22 hours. BilRI played a role in the internalization of IL-1β in the gingival model system but did not affect either IL-8 or IL-6 uptake. However, bilRI deletion did not entirely prevent IL-1β internalization, and the binding of cytokines to BilRI was relatively weak. Thus, BilRI might sequester cytokines on the surface of A. actinomycetemcomitans to facilitate the internalization process in low local cytokine concentrations.}, } @article {pmid27458867, year = {2016}, author = {Arnaouteli, S and MacPhee, CE and Stanley-Wall, NR}, title = {Just in case it rains: building a hydrophobic biofilm the Bacillus subtilis way.}, journal = {Current opinion in microbiology}, volume = {34}, number = {}, pages = {7-12}, doi = {10.1016/j.mib.2016.07.012}, pmid = {27458867}, issn = {1879-0364}, support = {BB/I019464/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L006804/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacillus subtilis/*physiology ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Hydrophobic and Hydrophilic Interactions ; }, abstract = {Over the millennia, diverse species of bacteria have evolved multiple independent mechanisms to structure sessile biofilm communities that confer protection and stability to the inhabitants. The Gram-positive soil bacterium Bacillus subtilis biofilm presents as an architecturally complex, highly hydrophobic community that resists wetting by water, solvents, and biocides. This remarkable property is conferred by a small secreted protein called BslA, which self-assembles into an organized lattice at an interface. In the biofilm, production of BslA is tightly regulated and the resultant protein is secreted into the extracellular environment where it forms a very effective communal barrier allowing the resident B. subtilis cells to shelter under the protection of a protein raincoat.}, } @article {pmid27458454, year = {2016}, author = {He, Z and Huang, Z and Zhou, W and Tang, Z and Ma, R and Liang, J}, title = {Anti-biofilm Activities from Resveratrol against Fusobacterium nucleatum.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1065}, pmid = {27458454}, issn = {1664-302X}, abstract = {Fusobacterium nucleatum is a Gram-negative, anaerobic bacterium that plays an important role in dental plaque biofilm formation. In this study, we evaluate the effect of resveratrol, a phytoalexin compound, on F. nucleatum biofilm formation. The effects of different concentrations of resveratrol on biofilms formed on 96-well microtiter plates at different time points were determined by the MTT assay. The structures and thicknesses of the biofilm were observed by confocal laser scanning microscopy (CLSM), and gene expression was investigated by real-time PCR. The results showed that resveratrol at sub-MIC levels can significantly decrease biofilm formation, whereas it does not affect the bacterial growth rate. It was observed by CLSM images that the biofilm was visually decreased with increasing concentrations of resveratrol. Gene expression was down regulated in the biofilm in the presence of resveratrol. Our results revealed that resveratrol can effectively inhibit biofilm formation.}, } @article {pmid27458233, year = {2016}, author = {Schilcher, K and Andreoni, F and Dengler Haunreiter, V and Seidl, K and Hasse, B and Zinkernagel, AS}, title = {Modulation of Staphylococcus aureus Biofilm Matrix by Subinhibitory Concentrations of Clindamycin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {5957-5967}, pmid = {27458233}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/drug effects ; Clindamycin/administration & dosage/*pharmacology ; Dose-Response Relationship, Drug ; Extracellular Matrix/drug effects/genetics ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Mutation ; Staphylococcus aureus/*drug effects/isolation & purification/physiology ; }, abstract = {Staphylococcus aureus biofilms are extremely difficult to treat. They provide a protected niche for the bacteria, rendering them highly recalcitrant toward host defenses as well as antibiotic treatment. Bacteria within a biofilm are shielded from the immune system by the formation of an extracellular polymeric matrix, composed of polysaccharides, extracellular DNA (eDNA), and proteins. Many antibiotics do not readily penetrate biofilms, resulting in the presence of subinhibitory concentrations of antibiotics. Here, we show that subinhibitory concentrations of clindamycin triggered a transcriptional stress response in S. aureus via the alternative sigma factor B (σ(B)) and upregulated the expression of the major biofilm-associated genes atlA, lrgA, agrA, the psm genes, fnbA, and fnbB Our data suggest that subinhibitory concentrations of clindamycin alter the ability of S. aureus to form biofilms and shift the composition of the biofilm matrix toward higher eDNA content. An understanding of the molecular mechanisms underlying biofilm assembly and dispersal in response to subinhibitory concentrations of clinically relevant antibiotics such as clindamycin is critical to further optimize antibiotic treatment strategies of biofilm-associated S. aureus infections.}, } @article {pmid27458231, year = {2016}, author = {Reen, FJ and Phelan, JP and Gallagher, L and Woods, DF and Shanahan, RM and Cano, R and Ó Muimhneacháin, E and McGlacken, GP and O'Gara, F}, title = {Exploiting Interkingdom Interactions for Development of Small-Molecule Inhibitors of Candida albicans Biofilm Formation.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {5894-5905}, pmid = {27458231}, issn = {1098-6596}, mesh = {4-Quinolones/chemistry/pharmacology ; Antifungal Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/*drug effects/physiology ; Cell Line ; Fungal Proteins/genetics ; Gene Expression Regulation, Fungal/drug effects ; Humans ; Membrane Glycoproteins/genetics ; Pseudomonas aeruginosa/*chemistry/drug effects/pathogenicity ; Quinolones/chemistry/pharmacology ; Small Molecule Libraries/chemistry/*pharmacology ; }, abstract = {A rapid decline in the development of new antimicrobial therapeutics has coincided with the emergence of new and more aggressive multidrug-resistant pathogens. Pathogens are protected from antibiotic activity by their ability to enter an aggregative biofilm state. Therefore, disrupting this process in pathogens is a key strategy for the development of next-generation antimicrobials. Here, we present a suite of compounds, based on the Pseudomonas aeruginosa 2-heptyl-4(1H)-quinolone (HHQ) core quinolone interkingdom signal structure, that exhibit noncytotoxic antibiofilm activity toward the fungal pathogen Candida albicans In addition to providing new insights into what is a clinically important bacterium-fungus interaction, the capacity to modularize the functionality of the quinolone signals is an important advance in harnessing the therapeutic potential of signaling molecules in general. This provides a platform for the development of potent next-generation small-molecule therapeutics targeting clinically relevant fungal pathogens.}, } @article {pmid27458213, year = {2016}, author = {Hogan, S and Zapotoczna, M and Stevens, NT and Humphreys, H and O'Gara, JP and O'Neill, E}, title = {Eradication of Staphylococcus aureus Catheter-Related Biofilm Infections Using ML:8 and Citrox.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {5968-5975}, pmid = {27458213}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Caprylates/*pharmacology ; Catheter-Related Infections/*drug therapy ; Drug Evaluation, Preclinical/methods ; Flavonoids/*pharmacology ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/drug effects/pathogenicity ; Rats, Sprague-Dawley ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects/pathogenicity ; }, abstract = {Staphylococci are a leading cause of catheter-related infections (CRIs) due to biofilm formation. CRIs are typically managed by either device removal or systemic antibiotics, often in combination with catheter lock solutions (CLSs). CLSs provide high concentrations of the antimicrobial agent at the site of infection. However, the most effective CLSs against staphylococcal biofilm-associated infections have yet to be determined. The purpose of this study was to evaluate the efficacy and suitability of two newly described antimicrobial agents, ML:8 and Citrox, as CLSs against Staphylococcus aureus biofilms. ML:8 (1% [vol/vol]) and Citrox (1% [vol/vol]), containing caprylic acid and flavonoids, respectively, were used to treat S. aureus biofilms grown in vitro using newly described static and flow biofilm assays. Both agents reduced biofilm viability >97% after 24 h of treatment. Using a rat model of CRI, ML:8 was shown to inactivate early-stage S. aureus biofilms in vivo, while Citrox inactivated established, mature in vivo biofilms. Cytotoxicity and hemolytic activity of ML:8 and Citrox were equivalent to those of other commercially available CLSs. Neither ML:8 nor Citrox induced a cytokine response in human whole blood, and exposure of S. aureus to either agent for 90 days was not associated with any increase in resistance. Taken together, these data reveal the therapeutic potential of these agents for the treatment of S. aureus catheter-related biofilm infections.}, } @article {pmid27456160, year = {2016}, author = {Wojnicz, D and Tichaczek-Goska, D and Korzekwa, K and Kicia, M and Hendrich, AB}, title = {Study of the impact of cranberry extract on the virulence factors and biofilm formation by Enterococcus faecalis strains isolated from urinary tract infections.}, journal = {International journal of food sciences and nutrition}, volume = {67}, number = {8}, pages = {1005-1016}, doi = {10.1080/09637486.2016.1211996}, pmid = {27456160}, issn = {1465-3478}, mesh = {Biofilms/drug effects/growth & development ; Enterococcus faecalis/*drug effects/*pathogenicity/physiology ; Fruit and Vegetable Juices/analysis ; Genes, Bacterial/drug effects ; Gram-Positive Bacterial Infections/microbiology/*prevention & control ; Humans ; In Vitro Techniques ; Plant Extracts/pharmacology ; Urinary Tract Infections/microbiology/*prevention & control ; Vaccinium macrocarpon/*chemistry ; Virulence Factors/biosynthesis/genetics ; }, abstract = {Drinking of cranberry fruit juice and application of commercial preparations containing the cranberry extracts are recommended in the prevention and treatment of urinary tract infections (UTIs), especially in women with recurrent UTIs. Many studies focus on the activity of cranberries against uropathogenic Escherichia coli (E. coli) strains. However, the knowledge of the cranberry effect on Gram-positive Enterococcus faecalis (E. faecalis) is limited. Therefore, the aim of our study was to establish the activity of commercial concentrated cranberry extract on the growth, virulence factors and biofilm formation of E. faecalis strains isolated from urine. Minimal inhibitory concentrations (MICs) of cranberry extract were determined by the broth microdilution method. Disc diffusion method was used to determine antimicrobial susceptibility. The impact of cranberry extract on bacterial survival, hydrophobicity, synthesis of lipase, lecithinase, DNase, hemolysin, gelatinase and biofilm mass was determined. Results show that cranberry extract inhibits the growth, enzymatic activities of bacteria and limits biofilm formation. The antibacterial activities of the studied cranberry extract confirm that it could be successfully used in prevention of UTIs caused by E. faecalis.}, } @article {pmid27453977, year = {2016}, author = {Yano, J and Yu, A and Fidel, PL and Noverr, MC}, title = {Transcription Factors Efg1 and Bcr1 Regulate Biofilm Formation and Virulence during Candida albicans-Associated Denture Stomatitis.}, journal = {PloS one}, volume = {11}, number = {7}, pages = {e0159692}, pmid = {27453977}, issn = {1932-6203}, support = {R01 DE022069/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Candida albicans/*physiology ; Candidiasis/*microbiology ; Colony Count, Microbial ; DNA-Binding Proteins/*genetics/metabolism ; Disease Models, Animal ; Fungal Proteins/*genetics/metabolism ; Humans ; Male ; Mouth Mucosa/microbiology ; Rats ; Stomatitis, Denture/*microbiology ; Transcription Factors/*genetics/metabolism ; Virulence/genetics ; }, abstract = {Denture stomatitis (DS) is characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. The disease is caused by Candida albicans, which readily colonizes and form biofilms on denture materials. While evidence for biofilms on abiotic and biotic surfaces initiating Candida infections is accumulating, a role for biofilms in DS remains unclear. Using an established model of DS in immunocompetent animals, the purpose of this study was to determine the role of biofilm formation in mucosal damage during pathogenesis using C. albicans or mutants defective in morphogenesis (efg1-/-) or biofilm formation (bcr1-/-). For in vivo analyses, rats fitted with custom dentures, consisting of fixed and removable parts, were inoculated with wild-type C. albicans, mutants or reconstituted strains and monitored weekly for fungal burden (denture and palate), body weight and tissue damage (LDH) for up to 8 weeks. C. albicans wild-type and reconstituted mutants formed biofilms on dentures and palatal tissues under in vitro, ex vivo and in vivo conditions as indicated by microscopy demonstrating robust biofilm architecture and extracellular matrix (ECM). In contrast, both efg1-/- and bcr1-/- mutants exhibited poor biofilm growth with little to no ECM. In addition, quantification of fungal burden showed reduced colonization throughout the infection period on dentures and palates of rats inoculated with efg1-/-, but not bcr1-/-, compared to controls. Finally, rats inoculated with efg1-/- and bcr1-/- mutants had minimal palatal tissue damage/weight loss while those inoculated with wild-type or reconstituted mutants showed evidence of tissue damage and exhibited stunted weight gain. These data suggest that biofilm formation is associated with tissue damage during DS and that Efg1 and Bcr1, both central regulators of virulence in C. albicans, have pivotal roles in pathogenesis of DS.}, } @article {pmid27449541, year = {2016}, author = {Nakamura, K and Shirato, M and Kanno, T and Örtengren, U and Lingström, P and Niwano, Y}, title = {Antimicrobial activity of hydroxyl radicals generated by hydrogen peroxide photolysis against Streptococcus mutans biofilm.}, journal = {International journal of antimicrobial agents}, volume = {48}, number = {4}, pages = {373-380}, doi = {10.1016/j.ijantimicag.2016.06.007}, pmid = {27449541}, issn = {1872-7913}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Colony Count, Microbial ; Hydrogen Peroxide/*metabolism ; Hydroxyl Radical/*pharmacology ; Microbial Viability/drug effects ; Microscopy, Confocal ; *Photolysis ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {Prevention of dental caries with maximum conservation of intact tooth substance remains a challenge in dentistry. The present study aimed to evaluate the antimicrobial effect of H2O2 photolysis on Streptococcus mutans biofilm, which may be a novel antimicrobial chemotherapy for treating caries. S. mutans biofilm was grown on disk-shaped hydroxyapatite specimens. After 1-24 h of incubation, growth was assessed by confocal laser scanning microscopy and viable bacterial counting. Resistance to antibiotics (amoxicillin and erythromycin) was evaluated by comparing bactericidal effects on the biofilm with those on planktonic bacteria. To evaluate the effect of the antimicrobial technique, the biofilm was immersed in 3% H2O2 and was irradiated with an LED at 365 nm for 1 min. Viable bacterial counts in the biofilm were determined by colony counting. The thickness and surface coverage of S. mutans biofilm increased with time, whereas viable bacterial counts plateaued after 6 h. When 12- and 24-h-old biofilms were treated with the minimum concentration of antibiotics that killed viable planktonic bacteria with 3 log reduction, their viable counts were not significantly decreased, suggesting the biofilm acquired antibiotic resistance by increasing its thickness. By contrast, hydroxyl radicals generated by photolysis of 3% H2O2 effectively killed S. mutans in 24-h-old biofilm, with greater than 5 log reduction. The technique based on H2O2 photolysis is a potentially powerful adjunctive antimicrobial chemotherapy for caries treatment.}, } @article {pmid27448237, year = {2016}, author = {Hiramatsu, Y and Saito, M and Otsuka, N and Suzuki, E and Watanabe, M and Shibayama, K and Kamachi, K}, title = {BipA Is Associated with Preventing Autoagglutination and Promoting Biofilm Formation in Bordetella holmesii.}, journal = {PloS one}, volume = {11}, number = {7}, pages = {e0159999}, pmid = {27448237}, issn = {1932-6203}, mesh = {Agglutination/*genetics ; Agglutination Tests ; Amino Acid Sequence ; Animals ; Bacterial Outer Membrane Proteins/chemistry/*genetics/*metabolism ; *Biofilms ; Bordetella/*physiology ; Bordetella Infections/microbiology ; Gene Expression Regulation, Bacterial ; Mice ; Mutation ; Pneumonia, Bacterial/microbiology ; }, abstract = {Bordetella holmesii causes both invasive and respiratory diseases in humans. Although the number of cases of pertussis-like respiratory illnesses due to B. holmesii infection has increased in the last decade worldwide, little is known about the virulence factors of the organism. Here, we analyzed a B. holmesii isolate that forms large aggregates and precipitates in suspension, and subsequently demonstrated that the autoagglutinating isolate is deficient in Bordetella intermediate protein A (BipA) and that this deletion is caused by a frame-shift mutation in the bipA gene. A BipA-deficient mutant generated by homologous recombination also exhibited the autoagglutination phenotype. Moreover, the BipA mutant adhered poorly to an abiotic surface and failed to form biofilms, as did two other B. holmesii autoagglutinating strains, ATCC 51541 and ATCC 700053, which exhibit transcriptional down-regulation of bipA gene expression, indicating that autoagglutination indirectly inhibits biofilm formation. In a mouse intranasal infection model, the BipA mutant showed significantly lower levels of initial lung colonization than did the parental strain (P < 0.01), suggesting that BipA might be a critical virulence factor in B. holmesii respiratory infection. Together, our findings suggest that BipA production plays an essential role in preventing autoagglutination and indirectly promoting biofilm formation by B. holmesii.}, } @article {pmid27447147, year = {2016}, author = {Pereira, J and Morsch, CS and Henriques, B and Nascimento, RM and Benfatti, CA and Silva, FS and López-López, J and Souza, JC}, title = {Removal Torque and Biofilm Accumulation at Two Dental Implant-Abutment Joints After Fatigue.}, journal = {The International journal of oral & maxillofacial implants}, volume = {31}, number = {4}, pages = {813-819}, doi = {10.11607/jomi.4173}, pmid = {27447147}, issn = {1942-4434}, mesh = {Analysis of Variance ; Biofilms/*growth & development ; Colony Count, Microbial ; Dental Abutments/*microbiology ; *Dental Implant-Abutment Design ; Dental Implants/*microbiology ; Dental Prosthesis, Implant-Supported/*microbiology ; *Dental Stress Analysis ; Humans ; Surface Properties ; Torque ; }, abstract = {PURPOSE: The aim of this study was to evaluate the removal torque and in vitro biofilm penetration at Morse taper and hexagonal implant-abutment joints after fatigue tests.

MATERIALS AND METHODS: Sixty dental implants were divided into two groups: (1) Morse taper and (2) external hexagon implant-abutment systems. Fatigue tests on the implant-abutment assemblies were performed at a normal force (FN) of 50 N at 1.2 Hz for 500,000 cycles in growth medium containing human saliva for 72 hours. Removal torque mean values (n = 10) were measured after fatigue tests. Abutments were then immersed in 1% protease solution in order to detach the biofilms for optical density and colony-forming unit (CFU/cm²) analyses. Groups of implant-abutment assemblies (n = 8) were cross-sectioned at 90 degrees relative to the plane of the implant-abutment joints for the microgap measurement by field-emission guns scanning electron microscopy.

RESULTS: Mean values of removal torque on abutments were significantly lower for both Morse taper (22.1 ± 0.5 μm) and external hexagon (21.1 ± 0.7 μm) abutments after fatigue tests than those recorded without fatigue tests (respectively, 24 ± 0.5 μm and 24.8 ± 0.6 μm) in biofilm medium for 72 hours (P = .04). Mean values of microgap size for the Morse taper joints were statistically signicantly lower without fatigue tests (1.7 ± 0.4 μm) than those recorded after fatigue tests (3.2 ± 0.8 μm). Also, mean values of microgap size for external hexagon joints free of fatigue were statistically signicantly lower (1.5 ± 0.4 μm) than those recorded after fatigue tests (8.1 ± 1.7 μm) (P < .05). The optical density of biofilms and CFU mean values were lower on Morse taper abutments (Abs630nm at 0.06 and 2.9 × 10⁴ CFU/cm²) than that on external hexagon abutments (Abs630nm at 0.08 and 4.5 × 10⁴ CFU/cm²) (P = .01).

CONCLUSION: The mean values of removal torque, microgap size, and biofilm density recorded at Morse taper joints were lower in comparison to those recorded at external hexagon implant-abutment joints after fatigue tests in a simulated oral environment for 72 hours.}, } @article {pmid27446060, year = {2016}, author = {Yan, F and Yu, Y and Wang, L and Luo, Y and Guo, JH and Chai, Y}, title = {The comER Gene Plays an Important Role in Biofilm Formation and Sporulation in both Bacillus subtilis and Bacillus cereus.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1025}, pmid = {27446060}, issn = {1664-302X}, abstract = {Bacteria adopt alternative cell fates during development. In Bacillus subtilis, the transition from planktonic growth to biofilm formation and sporulation is controlled by a complex regulatory circuit, in which the most important event is activation of Spo0A, a transcription factor and a master regulator for genes involved in both biofilm formation and sporulation. In B. cereus, the regulatory pathway controlling biofilm formation and cell differentiation is much less clear. In this study, we show that a novel gene, comER, plays a significant role in biofilm formation as well as sporulation in both B. subtilis and B. cereus. Mutations in the comER gene result in defects in biofilm formation and a delay in spore formation in the two Bacillus species. Our evidence supports the idea that comER may be part of the regulatory circuit that controls Spo0A activation. comER likely acts upstream of sda, a gene encoding a small checkpoint protein for both sporulation and biofilm formation, by blocking the phosphor-relay and thereby Spo0A activation. In summary, our studies outlined a conserved, positive role for comER, a gene whose function was previously uncharacterized, in the regulation of biofilm formation and sporulation in the two Bacillus species.}, } @article {pmid27446042, year = {2016}, author = {Bronnec, V and Turoňová, H and Bouju, A and Cruveiller, S and Rodrigues, R and Demnerova, K and Tresse, O and Haddad, N and Zagorec, M}, title = {Adhesion, Biofilm Formation, and Genomic Features of Campylobacter jejuni Bf, an Atypical Strain Able to Grow under Aerobic Conditions.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1002}, pmid = {27446042}, issn = {1664-302X}, abstract = {Campylobacter jejuni is the leading cause of bacterial enteritis in Europe. Human campylobacteriosis cases are frequently associated to the consumption of contaminated poultry meat. To survive under environmental conditions encountered along the food chain, i.e., from poultry digestive tract its natural reservoir to the consumer's plate, this pathogen has developed adaptation mechanisms. Among those, biofilm lifestyle has been suggested as a strategy to survive in the food environment and under atmospheric conditions. Recently, the clinical isolate C. jejuni Bf has been shown to survive and grow under aerobic conditions, a property that may help this strain to better survive along the food chain. The aim of this study was to evaluate the adhesion capacity of C. jejuni Bf and its ability to develop a biofilm. C. jejuni Bf can adhere to abiotic surfaces and to human epithelial cells, and can develop biofilm under both microaerobiosis and aerobiosis. These two conditions have no influence on this strain, unlike results obtained with the reference strain C. jejuni 81-176, which harbors only planktonic cells under aerobic conditions. Compared to 81-176, the biofilm of C. jejuni Bf is more homogenous and cell motility at the bottom of biofilm was not modified whatever the atmosphere used. C. jejuni Bf whole genome sequence did not reveal any gene unique to this strain, suggesting that its unusual property does not result from acquisition of new genetic material. Nevertheless some genetic particularities seem to be shared only between Bf and few others strains. Among the main features of C. jejuni Bf genome we noticed (i) a complete type VI secretion system important in pathogenicity and environmental adaptation; (ii) a mutation in the oorD gene involved in oxygen metabolism; and (iii) the presence of an uncommon insertion of a 72 amino acid coding sequence upstream from dnaK, which is involved in stress resistance. Therefore, the atypical behavior of this strain under aerobic atmosphere may result from the combination of insertions and mutations. In addition, the comparison of mRNA transcript levels of several genes targeted through genome analysis suggests the modification of regulatory processes in this strain.}, } @article {pmid27446013, year = {2016}, author = {Kimyon, Ö and Das, T and Ibugo, AI and Kutty, SK and Ho, KK and Tebben, J and Kumar, N and Manefield, M}, title = {Serratia Secondary Metabolite Prodigiosin Inhibits Pseudomonas aeruginosa Biofilm Development by Producing Reactive Oxygen Species that Damage Biological Molecules.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {972}, pmid = {27446013}, issn = {1664-302X}, abstract = {Prodigiosin is a heterocyclic bacterial secondary metabolite belonging to the class of tripyrrole compounds, synthesized by various types of bacteria including Serratia species. Prodigiosin has been the subject of intense research over the last decade for its ability to induce apoptosis in several cancer cell lines. Reports suggest that prodigiosin promotes oxidative damage to double-stranded DNA (dsDNA) in the presence of copper ions and consequently leads to inhibition of cell-cycle progression and cell death. However, prodigiosin has not been previously implicated in biofilm inhibition. In this study, the link between prodigiosin and biofilm inhibition through the production of redox active metabolites is presented. Our study showed that prodigiosin (500 μM) (extracted from Serratia marcescens culture) and a prodigiosin/copper(II) (100 μM each) complex have strong RNA and dsDNA cleaving properties while they have no pronounced effect on protein. Results support a role for oxidative damage to biomolecules by H2O2 and hydroxyl radical generation. Further, it was demonstrated that reactive oxygen species scavengers significantly reduced the DNA and RNA cleaving property of prodigiosin. P. aeruginosa cell surface hydrophobicity and biofilm integrity were significantly altered due to the cleavage of nucleic acids by prodigiosin or the prodigiosin/copper(II) complex. In addition, prodigiosin also facilitated the bactericidal activity. The ability of prodigiosinto cause nucleic acid degradation offers novel opportunities to interfere with extracellular DNA dependent bacterial biofilms.}, } @article {pmid28357315, year = {2015}, author = {Secor, PR and Jennings, LK and Michaels, LA and Sweere, JM and Singh, PK and Parks, WC and Bollyky, PL}, title = {Biofilm assembly becomes crystal clear - filamentous bacteriophage organize the Pseudomonas aeruginosa biofilm matrix into a liquid crystal.}, journal = {Microbial cell (Graz, Austria)}, volume = {3}, number = {1}, pages = {49-52}, doi = {10.15698/mic2016.01.475}, pmid = {28357315}, issn = {2311-2638}, abstract = {Pseudomonas aeruginosa is an opportunistic bacterial pathogen associated with many types of chronic infection. At sites of chronic infection, such as the airways of people with cystic fibrosis (CF), P. aeruginosa forms biofilm-like aggregates. These are clusters of bacterial cells encased in a polymer-rich matrix that shields bacteria from environmental stresses and antibiotic treatment. When P. aeruginosa forms a biofilm, large amounts of filamentous Pf bacteriophage (phage) are produced. Unlike most phage that typically lyse and kill their bacterial hosts, filamentous phage of the genus Inovirus, which includes Pf phage, often do not, and instead are continuously extruded from the bacteria. Here, we discuss the implications of the accumulation of filamentous Pf phage in the biofilm matrix, where they interact with matrix polymers to organize the biofilm into a highly ordered liquid crystal. This structural configuration promotes bacterial adhesion, desiccation survival, and antibiotic tolerance - all features typically associated with biofilms. We propose that Pf phage make structural contributions to P. aeruginosa biofilms and that this constitutes a novel form of symbiosis between bacteria and bacteriophage.}, } @article {pmid28357266, year = {2015}, author = {Chen, Y and Gozzi, K and Chai, Y}, title = {A bacterial volatile signal for biofilm formation.}, journal = {Microbial cell (Graz, Austria)}, volume = {2}, number = {10}, pages = {406-408}, doi = {10.15698/mic2015.10.233}, pmid = {28357266}, issn = {2311-2638}, abstract = {Bacteria constantly monitor the environment they reside in and respond to potential changes in the environment through a variety of signal sensing and transduction mechanisms in a timely fashion. Those signaling mechanisms often involve application of small, diffusible chemical molecules. Volatiles are a group of small air-transmittable chemicals that are produced universally by all kingdoms of organisms. Past studies have shown that volatiles can function as cell-cell communication signals not only within species, but also cross-species. However, little is known about how the volatile-mediated signaling mechanism works. In our recent study (Chen, et al. mBio (2015), 6: e00392-15), we demonstrated that the soil bacterium Bacillus subtilis uses acetic acid as a volatile signal to coordinate the timing of biofilm formation within physically separated cells in the community. We also showed that the bacterium possesses an intertwined gene network to produce, secrete, sense, and respond to acetic acid, in stimulating biofilm formation. Interestingly, many of those genes are highly conserved in other bacterial species, raising the possibility that acetic acid may act as a volatile signal for cross-species communication.}, } @article {pmid27885354, year = {2015}, author = {Zandona, F and Soini, HA and Novotny, MV and Santiago, E and Eckert, GJ and Preisser, JS and Benecha, HK and Arthur, RA and Zero, DT}, title = {A Potential Biofilm Metabolite Signature for Caries Activity - A Pilot Clinical Study.}, journal = {Metabolomics : open access}, volume = {5}, number = {1}, pages = {}, pmid = {27885354}, issn = {2153-0769}, support = {R56 DE017890/DE/NIDCR NIH HHS/United States ; }, abstract = {BACKGROUND: This study's aim was to compare the dental biofilm metabolite-profile of caries-active (N=11) or caries-free (N=4) children by gas chromatography-mass spectrometry (GC/MS) analyses.

METHODS: Samples collected after overnight fasting, with or without a previous glucose rinse, were combined for each child based on the caries status of the site, re-suspended in ethanol and analyzed by GC/MS.

RESULTS: Biofilm from caries-active sites exhibited a different chromatographic profile compared to caries-free sites. Qualitative and quantitative analysis suggested a special cluster of branched alcohols and esters present at substantially higher intensity in biofilms of caries-active sites.

CONCLUSIONS: This pilot study indicates that there are metabolites present in the biofilm which have the potential to provide a characteristic metabolomics signature for caries activity.}, } @article {pmid27873644, year = {2015}, author = {Mothiba, MT and Anderson, R and Fourie, B and Germishuizen, WA and Cholo, MC}, title = {Effects of clofazimine on planktonic and biofilm growth of Mycobacterium tuberculosis and Mycobacterium smegmatis.}, journal = {Journal of global antimicrobial resistance}, volume = {3}, number = {1}, pages = {13-18}, doi = {10.1016/j.jgar.2014.12.001}, pmid = {27873644}, issn = {2213-7173}, abstract = {Mycobacteria form lipid-rich biofilms that restrict the efficacy of antimicrobial chemotherapy, possibly necessitating the use of lipophilic antibiotics. In the current study, the activity of one such agent, clofazimine, against Mycobacterium tuberculosis and Mycobacterium smegmatis planktonic cells and biofilms was investigated. Minimum inhibitory concentrations (MICs) of clofazimine were determined for planktonic cultures, whilst minimum bactericidal concentrations (MBCs) were determined for planktonic, biofilm-producing and biofilm-encased organisms using standard bacteriological procedures. The effects of clofazimine on biofilm formation and the stability of pre-formed biofilm were measured using a crystal violet-based spectrophotometric procedure. In the case of M. smegmatis, clofazimine was found to be active against planktonic phase (MICs and MBCs of 2.5mg/L and >20mg/L, respectively) and biofilm-producing organisms (MBC of 2.5mg/L); clofazimine demonstrated greater activity against M. tuberculosis, corresponding values of 0.06, 5 and 0.3mg/L. Although clofazimine inhibited biofilm production both by M. tuberculosis and M. smegmatis (P<0.05 at ≥0.07mg/L and ≥0.3mg/L, respectively) and appeared to reduce the pre-formed M. tuberculosis biofilm, addition of antimicrobial agent to pre-existing biofilm matrices failed to kill biofilm-encased organisms. In conclusion, clofazimine is more effective against M. tuberculosis than against M. smegmatis, exhibiting bactericidal activity both for actively growing and slowly replicating bacilli but not for non-replicating organisms of both species.}, } @article {pmid27563687, year = {2015}, author = {de la Fuente-Núñez, C and Hancock, RE}, title = {Using anti-biofilm peptides to treat antibiotic-resistant bacterial infections.}, journal = {Postdoc journal : a journal of postdoctoral research and postdoctoral affairs}, volume = {3}, number = {2}, pages = {1-8}, pmid = {27563687}, issn = {2328-9791}, support = {R21 AI098701/AI/NIAID NIH HHS/United States ; R33 AI098701/AI/NIAID NIH HHS/United States ; }, abstract = {Host defense (antimicrobial) peptides (HDPs) are produced by virtually all organisms and have an important role in protection against microbial infections. Some naturally occurring peptides such as the human cathelicidin LL-37 and the bovine peptide indolicidin have been shown to inhibit bacterial biofilm development. Rearrangement and substantial modification of the amino acid sequence of these and other HDPs has led to the identification of small synthetic peptides with increased, broad-spectrum anti-biofilm activity that is independent of activity vs. planktonic cells. Some of these peptides have also been shown to act in synergy with antibiotics commonly used in the clinic to prevent biofilm formation and eradicate pre-existing biofilms. Recently, the mechanism of action of one of these peptides (i.e., 1018) was shown to involve binding to and causing degradation of the second messenger stress response nucleotide ppGpp, which plays an important role in biofilm formation and maintenance. Here, we review recent progress in the field of anti-biofilm peptides and propose future directions to further develop these therapeutic agents.}, } @article {pmid28324552, year = {2015}, author = {Vasu, D and Sunitha, MM and Srikanth, L and Swarupa, V and Prasad, UV and Sireesha, K and Yeswanth, S and Kumar, PS and Venkatesh, K and Chaudhary, A and Sarma, PV}, title = {In Staphylococcus aureus the regulation of pyruvate kinase activity by serine/threonine protein kinase favors biofilm formation.}, journal = {3 Biotech}, volume = {5}, number = {4}, pages = {505-512}, pmid = {28324552}, issn = {2190-572X}, abstract = {Staphylococcus aureus, a natural inhabitant of nasopharyngeal tract, survives mainly as biofilms. Previously we have observed that S. aureus ATCC 12600 grown under anaerobic conditions exhibited high rate of biofilm formation and L-lactate dehydrogenase activity. Thus, the concentration of pyruvate plays a critical role in S. aureus, which is primarily catalyzed by pyruvate kinase (PK). Analyses of the PK gene sequence (JN645815) revealed presence of PknB site in PK gene indicating that phosphorylation may be influencing the functioning of PK. To establish this hypothesis the pure enzymes of S. aureus ATCC 12600 were obtained by expressing these genes in PK 1 and PV 1 (JN695616) clones and passing the cytosolic fractions through nickel metal chelate column. The molecular weights of pure recombinant PK and PknB are 63 and 73 kDa, respectively. The enzyme kinetics of pure PK showed K M of 0.69 ± 0.02 µM, while the K M of PknB for stpks (stpks = NLCNIPCSALLSSDITASVNCAK) substrate was 0.720 ± 0.08 mM and 0.380 ± 0.07 mM for autophosphorylation. The phosphorylated PK exhibited 40 % reduced activity (PK = 0.2 ± 0.015 μM NADH/min/ml to P-PK = 0.12 ± 0.01 μM NADH/min/ml). Elevated synthesis of pyruvate kinase was observed in S. aureus ATCC 12600 grown in anaerobic conditions suggesting that the formed pyruvate is more utilized in the synthesis phase, supporting increased rate of biofilm formation.}, } @article {pmid27873689, year = {2014}, author = {Adil, M and Singh, K and Verma, PK and Khan, AU}, title = {Eugenol-induced suppression of biofilm-forming genes in Streptococcus mutans: An approach to inhibit biofilms.}, journal = {Journal of global antimicrobial resistance}, volume = {2}, number = {4}, pages = {286-292}, doi = {10.1016/j.jgar.2014.05.006}, pmid = {27873689}, issn = {2213-7173}, abstract = {Streptococcus mutans is well documented as a major aetiological agent of dental caries. The ability to form a biofilm on tooth surfaces is the major virulence factor of this bacterium. The objective of this study was to evaluate the effect of eugenol on suppression of biofilm- and quorum sensing (QS)-related genes of S. mutans and to determine its putative mode of action. Eugenol was evaluated for its inhibitory activity against virulence properties such as adherence and biofilm formation. Morphological changes in the architecture of S. mutans and in the biofilm were analysed and observed using confocal laser scanning microscopy and transmission electron microscopy. The effects of eugenol on expression of biofilm- and QS-related genes (gtfB, gtfC, comDE, smu630, vicR, brpA, ftf, relA, gbpB and spaP) were checked by quantitative real-time PCR (qRT-PCR). The present data revealed that eugenol at a sub-minimum inhibitory concentration (sub-MIC) significantly downregulated the expression of tested genes but did not affect bacterial growth. These results suggest that a sub-MIC of eugenol can effectively suppress virulence genes. Thus, the results indicated that eugenol can inhibit caries-associated biofilm and showed its therapeutic potential against oral biofilm.}, } @article {pmid27873581, year = {2013}, author = {Esposito, S and Purrello, SM and Bonnet, E and Novelli, A and Tripodi, F and Pascale, R and Unal, S and Milkovich, G}, title = {Central venous catheter-related biofilm infections: An up-to-date focus on meticillin-resistant Staphylococcus aureus.}, journal = {Journal of global antimicrobial resistance}, volume = {1}, number = {2}, pages = {71-78}, doi = {10.1016/j.jgar.2013.03.002}, pmid = {27873581}, issn = {2213-7173}, abstract = {Central venous catheters are indispensable for the long-term treatment of seriously and chronically ill patients, but their use is often associated with a variety of complications; indeed, 90% of primary bloodstream infections are related to patients having a catheter. In studies performed in France, Germany and Italy, meticillin-resistant Staphylococcus aureus (MRSA) accounted for >50% of all S. aureus isolates obtained in catheter-related bloodstream infections (CRBSIs). These infections have a serious impact on long-term disability of the patient, a substantial additional financial burden for health systems, and high costs for patients. Decreasing the rate of CRBSIs requires a multidisciplinary approach, including behavioural and educational interventions and the insertion of the correct type of catheter. Although vancomycin remains the cornerstone of empirical therapy for CRBSIs caused by MRSA, combination of different antimicrobials and new approaches are indispensable to enhance the eradication of S. aureus biofilms and to manage the patient appropriately.}, } @article {pmid27574616, year = {2013}, author = {Metcalf, DG and Bowler, PG}, title = {Biofilm delays wound healing: A review of the evidence.}, journal = {Burns & trauma}, volume = {1}, number = {1}, pages = {5-12}, pmid = {27574616}, issn = {2321-3868}, abstract = {Biofilm is the predominant mode of life for bacteria and today it is implicated in numerous human diseases. A growing body of scientific and clinical evidence now exists regarding the presence of biofilm in wounds. This review summarizes the clinical experiences and in vivo evidence that implicate biofilm in delayed wound healing. The various mechanisms by which biofilm may impede healing are highlighted, including impaired epithelialization and granulation tissue formation, and reduced susceptibilities to antimicrobial agents and host defenses. Strategies to manage biofilm and encourage progression to wound healing are discussed; these include debridement and appropriate antimicrobial therapies which may be improved upon in the future with the emergence of anti-biofilm technologies.}, } @article {pmid27713308, year = {2010}, author = {Estrela, AB and Abraham, WR}, title = {Combining Biofilm-Controlling Compounds and Antibiotics as a Promising New Way to Control Biofilm Infections.}, journal = {Pharmaceuticals (Basel, Switzerland)}, volume = {3}, number = {5}, pages = {1374-1393}, pmid = {27713308}, issn = {1424-8247}, abstract = {Many bacteria grow on surfaces forming biofilms. In this structure, they are well protected and often high dosages of antibiotics cannot clear infectious biofilms. The formation and stabilization of biofilms are mediated by diffusible autoinducers (e.g. N-acyl homoserine lactones, small peptides, furanosyl borate diester). Metabolites interfering with this process have been identified in plants, animals and microbes, and synthetic analogues are known. Additionally, this seems to be not the only way to control biofilms. Enzymes capable of cleaving essential components of the biofilm matrix, e.g. polysaccharides or extracellular DNA, and thus weakening the biofilm architecture have been identified. Bacteria also have mechanisms to dissolve their biofilms and return to planktonic lifestyle. Only a few compounds responsible for the signalling of these processes are known, but they may open a completely novel line of biofilm control. All these approaches lead to the destruction of the biofilm but not the killing of the pathogens. Therefore, a combination of biofilm-destroying compounds and antibiotics to handle biofilm infections is proposed. In this article, different approaches to combine biofilm-controlling compounds and antibiotics to fight biofilm infections are discussed, as well as the balance between biofilm formation and virulence.}, } @article {pmid27234012, year = {2016}, author = {da Costa Luciano, C and Olson, N and Tipple, AF and Alfa, M}, title = {Evaluation of the ability of different detergents and disinfectants to remove and kill organisms in traditional biofilm.}, journal = {American journal of infection control}, volume = {44}, number = {11}, pages = {e243-e249}, doi = {10.1016/j.ajic.2016.03.040}, pmid = {27234012}, issn = {1527-3296}, mesh = {Bacterial Proteins/analysis ; Biofilms/*drug effects/growth & development ; Carbohydrates/analysis ; Colony Count, Microbial ; Detergents/*pharmacology ; Disinfectants/*pharmacology ; Enterococcus faecalis/*drug effects/physiology ; *Environmental Microbiology ; Microbial Viability/*drug effects ; Microscopy, Electron, Scanning ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {BACKGROUND: The objective of this study was to assess the ability of different detergent and disinfectant combinations to eradicate bacteria in traditional biofilm.

METHODS: Enterococcus faecalis and Pseudomonas aeruginosa were used to develop biofilm over 8 days. The biofilm on each minimum biofilm eradication concentration peg contained 8 log10 colony forming units (CFU)/cm[2] of both bacteria. The detergents evaluated were as follows: Prolystica Enzymatic 2X, Prolystica Neutral 2X, Neodisher, and Endozime Bio-Clean. The disinfectants evaluated were as follows: glutaraldehyde, accelerated hydrogen peroxide, and ortho-phthalaldehyde. Biofilm removal was evaluated using viable count, protein and carbohydrate quantitation, and scanning electron microscopy.

RESULTS: Only Prolystica Enzymatic 2X and Endozime Bio-Clean killed both E faecalis (3.90 log10 CFU/mL reduction) and P aeruginosa (3.96 log10 CFU/mL reduction) in suspension. None of the detergents tested could provide >1 log10 CFU/cm[2] reduction for bacteria within biofilm. Any combination of detergent and high-level disinfectant reduced the level of both E faecalis and P aeruginosa within biofilm by 3-5 log10 CFU/cm[2]. Although the combination of Endozime Bio-Clean and glutaraldehyde provided a 6 log10 reduction, it could not eliminate both bacteria within biofilm.

CONCLUSIONS: Our data indicate that if biofilm accumulates in flexible endoscope channels during repeated rounds of reprocessing, then neither the detergent nor high-level disinfectant will provide the expected level of bacterial removal or killing.}, } @article {pmid27240552, year = {2016}, author = {Grover, N and Plaks, JG and Summers, SR and Chado, GR and Schurr, MJ and Kaar, JL}, title = {Acylase-containing polyurethane coatings with anti-biofilm activity.}, journal = {Biotechnology and bioengineering}, volume = {113}, number = {12}, pages = {2535-2543}, doi = {10.1002/bit.26019}, pmid = {27240552}, issn = {1097-0290}, support = {R03 EB018422/EB/NIBIB NIH HHS/United States ; T32 GM007324/GM/NIGMS NIH HHS/United States ; }, mesh = {Amidohydrolases/*administration & dosage/chemistry ; Anti-Bacterial Agents/*administration & dosage/chemistry ; Aspergillus/*enzymology ; Biofilms/drug effects/*growth & development ; Coated Materials, Biocompatible/administration & dosage/chemical synthesis ; Polyurethanes/*chemistry ; Pseudomonas aeruginosa/drug effects/*physiology ; Quorum Sensing/drug effects/physiology ; }, abstract = {Due to the prevalence of biofilm-related infections, which are mediated by bacterial quorum sensing, there is a critical need for materials and coatings that resist biofilm formation. We have developed novel anti-biofilm coatings that disrupt quorum sensing in surface-associated bacteria via the immobilization of acylase in polyurethane films. Specifically, acylase from Aspergillus melleus was covalently immobilized in biomedical grade polyurethane coatings via multipoint covalent immobilization. Coatings containing acylase were enzymatically active and catalyzed the hydrolysis of the quorum sensing (QS) molecules N-butyryl-L-homoserine lactone (C4-LHL), N-hexanoyl-L-homoserine lactone (C6-LHL), and N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-LHL). In biofilm inhibition assays, immobilization of acylase led to an approximately 60% reduction in biofilm formation by Pseudomonas aeruginosa ATCC 10145 and PAO1. Inhibition of biofilm formation was consistent with a reduction in the secretion of pyocyanin, indicating the disruption of quorum sensing as the mechanism of the coating activity. Scanning electron microscopy further showed that acylase-containing coatings contained far fewer bacterial cells than control coatings that lacked acylase. Moreover, acylase-containing coatings retained 90% activity when stored dry at 37°C for 7 days and were more stable than the free enzyme in physiological conditions, including artificial urine. Ultimately, such coatings hold considerable promise for the clinical management of catheter-related infections as well as the prevention of infections in orthopedic applications (i.e., on hip and knee prostheses) and on contact lenses. Biotechnol. Bioeng. 2016;113: 2535-2543. © 2016 Wiley Periodicals, Inc.}, } @article {pmid27079455, year = {2016}, author = {Farkas, A and Crăciunaş, C and Chiriac, C and Szekeres, E and Coman, C and Butiuc-Keul, A}, title = {Exploring the Role of Coliform Bacteria in Class 1 Integron Carriage and Biofilm Formation During Drinking Water Treatment.}, journal = {Microbial ecology}, volume = {72}, number = {4}, pages = {773-782}, pmid = {27079455}, issn = {1432-184X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Base Sequence ; Biofilms/*growth & development ; DNA, Bacterial/genetics ; Disinfectants/*pharmacology ; Drinking Water/chemistry/*microbiology ; Drug Resistance, Bacterial/*genetics ; Enterobacteriaceae/*drug effects/*genetics/isolation & purification ; Integrases/genetics ; Membrane Transport Proteins/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Water Microbiology ; Water Purification/*methods ; }, abstract = {This study investigates the role of coliforms in the carriage of class 1 integron and biocide resistance genes in a drinking water treatment plant and explores the relationship between the carriage of such genes and the biofouling abilities of the strain. The high incidence of class 1 integron and biocide resistance genes (33.3 % of the isolates) highlights the inherent risk of genetic contamination posed by coliform populations during drinking water treatment. The association between the presence of intI1 gene and qac gene cassettes, especially qacH, was greater in biofilm cells. In coliforms recovered from biofilms, a higher frequency of class 1 integron elements and higher diversity of genetic patterns occurred, compared to planktonic cells. The coliform isolates under the study proved to mostly carry non-classical class 1 integrons lacking the typical qacEΔ1/sul1 genes or a complete tni module, but bearing the qacH gene. No link was found between the carriage of integron genes and the biofouling degree of the strain, neither in aerobic or in anaerobic conditions. Coliform bacteria isolated from established biofilms rather adhere in oxygen depleted environments, while the colonization ability of planktonic cells is not significantly affected by oxygen availability.}, } @article {pmid27399809, year = {2016}, author = {da Silva Negreiros Neto, T and Gardner, D and Hallwass, F and Leite, AJM and de Almeida, CG and Silva, LN and de Araújo Roque, A and de Bitencourt, FG and Barbosa, EG and Tasca, T and Macedo, AJ and de Almeida, MV and Giordani, RB}, title = {Activity of pyrrolizidine alkaloids against biofilm formation and Trichomonas vaginalis.}, journal = {Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie}, volume = {83}, number = {}, pages = {323-329}, doi = {10.1016/j.biopha.2016.06.033}, pmid = {27399809}, issn = {1950-6007}, mesh = {Biofilms/*drug effects ; Carbon-13 Magnetic Resonance Spectroscopy ; Cell Line ; Female ; Humans ; Microbial Viability/drug effects ; Monocrotaline/chemical synthesis/chemistry/isolation & purification/pharmacology ; Proton Magnetic Resonance Spectroscopy ; Pyrrolizidine Alkaloids/chemistry/isolation & purification/*pharmacology ; Staphylococcus epidermidis/drug effects/ultrastructure ; Trichomonas vaginalis/drug effects/*physiology ; }, abstract = {Crotalaria genus belongs to the subfamily Papilionoideae comprising about 600 species spread throughout tropical, neotropical and subtropical regions. In this study, seeds of Crolatalaria pallida were used to the isolation of usaramine, a pyrrolizidine alkaloid. Thus, Pseudomonas aeruginosa and Staphylococcus epidermidis were utilized as strains to test some activities of this alkaloid, such as antibiofilm and antibacterial. Meanwhile, monocrotaline obtained from Crotalaria retusa seeds, was used as the starting material for synthesis of necine base derivatives with anti-Trichomonas vaginalis potential. Alkaloids were characterized by 1D and 2D NMR techniques and GC-MS analysis. Usaramine demonstrated a highlighted antibiofilm activity against S. epidermidis by reducing more than 50% of biofilm formation without killing the bacteria, thus it could be assumed as a prototype for the development of new antibiofilm molecules for pharmaceutical and industrial purposes. Monocrotaline activity against T. vaginalis was evaluated and results indicated inhibition of 80% on parasite growth at 1mg/mL, in addition, neither cytotoxicity against vaginal epithelial cells nor hemolytic activity were observed. On the other hand, retronecine showed no anti-T. vaginalis activity while azido-retronecine was more active than monocrotaline killing 85% of the parasites at 1mg/mL. In conclusion, pyrrolizidine alkaloids are suggested as promising prototypes for new drugs especially for topical use.}, } @article {pmid27253755, year = {2016}, author = {Guisado, IM and Purswani, J and González-López, J and Pozo, C}, title = {An extractive membrane biofilm reactor as alternative technology for the treatment of methyl tert-butyl ether contaminated water.}, journal = {Biotechnology progress}, volume = {32}, number = {5}, pages = {1238-1245}, doi = {10.1002/btpr.2311}, pmid = {27253755}, issn = {1520-6033}, mesh = {Agrobacterium/drug effects/growth & development ; Biofilms/*drug effects ; *Bioreactors ; *Membranes, Artificial ; Methyl Ethers/*pharmacology ; Paenibacillus/drug effects/growth & development ; Rhodococcus/drug effects/growth & development ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Among the strategies developed for contaminated groundwater bioremediation, those based on the use of bacteria adhering to inert supports and establishing biofilms have gained great importance in this field. Extractive membrane biofilm reactor (EMBFR) technology offers productive solutions for the removal of volatile and semi-volatile compounds. EMBFR technology is based on the use of extractive semipermeable membranes through which contaminants migrate to the biological compartment in which microorganisms with pollutant biotransformation and/or mineralization capacities can grow, forming an active biofilm on the membrane surface. The objective of this study was to assess the use of three bacterial strains (Paenibacillus sp. SH7 CECT 8558, Agrobacterium sp. MS2 CECT 8557, and Rhodococcus ruber EE6 CECT 8612), as inoculum in a lab-scale EMBFR running for 28 days under aerobic conditions to eliminate methyl tert-butyl ether (MTBE) from water samples. Three different hydraulic retention times (1, 6, and 12 h) were employed. MTBE degradation values were determined daily by a gas GC-MS technique, as well as suspended bacterial growth. The biofilm established by the bacterial strains on the semipermeable membrane was detected by Field-Emission Scanning Electron Microscopy (FESEM) at the end of each experiment. The acute toxicity of the treated effluents and biomedium was determined by Microtox[©] assay (EC50).The results achieved from the MTBE degradation, biofilm formation, and toxicity analysis indicated that bacterial strains MS2 and EE6 were the best options as selective inoculum, although further research is needed, particularly with regard to their possible use as a mixed culture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1238-1245, 2016.}, } @article {pmid27318321, year = {2016}, author = {Pletzer, D and Coleman, SR and Hancock, RE}, title = {Anti-biofilm peptides as a new weapon in antimicrobial warfare.}, journal = {Current opinion in microbiology}, volume = {33}, number = {}, pages = {35-40}, pmid = {27318321}, issn = {1879-0364}, support = {R33 AI098701/AI/NIAID NIH HHS/United States ; MOP-123477//CIHR/Canada ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Antimicrobial Cationic Peptides/*pharmacology ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects/*growth & development ; Cyclic GMP/analogs & derivatives/metabolism ; Drug Synergism ; Escherichia coli/*drug effects ; Microbial Sensitivity Tests ; Prostheses and Implants/microbiology ; Prosthesis-Related Infections/drug therapy/microbiology ; Quorum Sensing/physiology ; Staphylococcus aureus/*drug effects ; }, abstract = {Microorganisms growing in a biofilm state are very resilient in the face of treatment by many antimicrobial agents. Biofilm infections are a significant problem in chronic and long-term infections, including those colonizing medical devices and implants. Anti-biofilm peptides represent a very promising approach to treat biofilm-related infections and have an extraordinary ability to interfere with various stages of the biofilm growth mode. Anti-biofilm peptides possess promising broad-spectrum activity in killing both Gram-positive and Gram-negative bacteria in biofilms, show strong synergy with conventional antibiotics, and act by targeting a universal stringent stress response. Understanding downstream processes at the molecular level will help to develop and design peptides with increased activity. Anti-biofilm peptides represent a novel, exciting approach to treating recalcitrant bacterial infections.}, } @article {pmid27444239, year = {2016}, author = {Ceresa, C and Rinaldi, M and Chiono, V and Carmagnola, I and Allegrone, G and Fracchia, L}, title = {Lipopeptides from Bacillus subtilis AC7 inhibit adhesion and biofilm formation of Candida albicans on silicone.}, journal = {Antonie van Leeuwenhoek}, volume = {109}, number = {10}, pages = {1375-1388}, doi = {10.1007/s10482-016-0736-z}, pmid = {27444239}, issn = {1572-9699}, mesh = {Antifungal Agents/*pharmacology ; Bacillus subtilis/*chemistry ; Biofilms/*drug effects ; Candida albicans/*drug effects/growth & development ; Lipopeptides/*pharmacology ; *Silicones ; }, abstract = {Candida albicans is the major fungus that colonises medical implants, causing device-associated infections with high mortality. Antagonistic bacterial products with interesting biological properties, such as biosurfactants, have recently been considered for biofilm prevention. This study investigated the activity of lipopeptide biosurfactant produced by Bacillus subtilis AC7 (AC7 BS) against adhesion and biofilm formation of C. albicans on medical-grade silicone elastomeric disks (SEDs). Chemical analysis, stability, surface activities of AC7 BS crude extract and physicochemical characterisation of the coated silicone disk surfaces were also carried out. AC7 BS showed a good reduction of water surface tension, low critical micelle concentration, good emulsification activity, thermal resistance and pH stability. Co-incubation with 2 mg ml(-1) AC7 BS significantly reduced adhesion and biofilm formation of three C. albicans strains on SEDs in a range of 67-69 % and of 56-57 %, respectively. On pre-coated SEDs, fungal adhesion and biofilm formation were reduced by 57-62 % and 46-47 %, respectively. Additionally, AC7 BS did not inhibit viability of C. albicans strains in both planktonic and sessile form. Chemical analysis of the crude extract revealed the presence of two families of lipopeptides, principally surfactin and a lower percentage of fengycin. The evaluation of surface wettability indicated that AC7 BS coating of SEDs surface was successful although uneven. AC7 BS significantly prohibits the initial deposition of C. albicans and slows biofilm growth, suggesting a potential role of biosurfactant coatings for preventing fungal infection associated with silicone medical devices.}, } @article {pmid27443239, year = {2016}, author = {Montagner, AF and Maske, TT and Opdam, NJ and de Soet, JJ and Cenci, MS and Huysmans, MC}, title = {Failed bonded interfaces submitted to microcosm biofilm caries development.}, journal = {Journal of dentistry}, volume = {52}, number = {}, pages = {63-69}, doi = {10.1016/j.jdent.2016.07.007}, pmid = {27443239}, issn = {1879-176X}, mesh = {*Biofilms ; Composite Resins ; Dental Bonding ; Dental Caries ; Dentin ; Dentin-Bonding Agents ; Materials Testing ; Resin Cements ; }, abstract = {OBJECTIVES: This study aimed to evaluate the dentin wall carious lesion development of different composite-dentin interfaces in the presence of two adhesive bonding materials in the gaps, using a microcosm biofilm model.

METHODS: Dentin samples were prepared (10.4mm(2)) and restored with a composite resin using two adhesive systems (etch-and-rinse and self-etch techniques). Different conditions with respect to composite-dentin interfaces were produced with a 200μm gap: failed bonded without ageing or after mechanical ageing, or non-bonded with or without the presence of adhesive material on the dentin wall. For cariogenic challenge, specimens were subjected to a biofilm microcosm model for 14days to create caries-like wall lesions. Before and after caries development, transverse wavelength-independent microradiography images were taken, and lesion depth and mineral loss were measured. Data were analysed with linear regression models (p<0.05).

RESULTS: The composite-dentin interface conditions significant influenced the caries development: lesion development was reduced by the presence of the adhesive material on dentin wall, while lesion development was increased by the mechanical ageing (p=0.019). There was no difference between the adhesive materials (p values>0.05).

CONCLUSION: Different composite-dentin interfaces influence wall lesion development in gaps, with the interfaces submitted to ageing showing less carious protection than those interfaces with the presence of adhesive covering the dentin.

CLINICAL SIGNIFICANCE: The presence of adhesive bonding material in the gaps plays a role on the wall caries lesion development.}, } @article {pmid27442433, year = {2016}, author = {Zapotoczna, M and O'Neill, E and O'Gara, JP}, title = {Untangling the Diverse and Redundant Mechanisms of Staphylococcus aureus Biofilm Formation.}, journal = {PLoS pathogens}, volume = {12}, number = {7}, pages = {e1005671}, pmid = {27442433}, issn = {1553-7374}, mesh = {Biofilms/*growth & development ; Staphylococcus aureus/*physiology ; }, } @article {pmid27441208, year = {2016}, author = {Meeker, DG and Jenkins, SV and Miller, EK and Beenken, KE and Loughran, AJ and Powless, A and Muldoon, TJ and Galanzha, EI and Zharov, VP and Smeltzer, MS and Chen, J}, title = {Synergistic Photothermal and Antibiotic Killing of Biofilm-Associated Staphylococcus aureus Using Targeted Antibiotic-Loaded Gold Nanoconstructs.}, journal = {ACS infectious diseases}, volume = {2}, number = {4}, pages = {241-250}, pmid = {27441208}, issn = {2373-8227}, support = {UL1 TR000039/TR/NCATS NIH HHS/United States ; R56 AI093126/AI/NIAID NIH HHS/United States ; P30 GM103450/GM/NIGMS NIH HHS/United States ; P20 GM103625/GM/NIGMS NIH HHS/United States ; T32 GM106999/GM/NIGMS NIH HHS/United States ; }, abstract = {Resistance to conventional antibiotics is a growing public health concern that is quickly outpacing the development of new antibiotics. This has led the Infectious Diseases Society of America (IDSA) to designate Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as "ESKAPE pathogens" on the basis of the rapidly decreasing availability of useful antibiotics. This emphasizes the urgent need for alternative therapeutic strategies to combat infections caused by these and other bacterial pathogens. In this study, we used Staphylococcus aureus (S. aureus) as a proof-of-principle ESKAPE pathogen to demonstrate that an appropriate antibiotic (daptomycin) can be incorporated into polydopamine-coated gold nanocages (AuNC@PDA) and that daptomycin-loaded AuNC@PDA can be conjugated to antibodies targeting a species-specific surface protein (staphylococcal protein A; Spa) as a means of achieving selective delivery of the nanoconstructs directly to the bacterial cell surface. Targeting specificity was confirmed by demonstrating a lack of binding to mammalian cells, reduced photothermal and antibiotic killing of the Spa-negative species Staphylococcus epidermidis, and reduced killing of S. aureus in the presence of unconjugated anti-Spa antibodies. We demonstrate that laser irradiation at levels within the current safety standard for use in humans can be used to achieve both a lethal photothermal effect and controlled release of the antibiotic, thus resulting in a degree of therapeutic synergy capable of eradicating viable S. aureus cells. The system was validated using planktonic bacterial cultures of both methicillin-sensitive and methicillin-resistant S. aureus strains and subsequently shown to be effective in the context of an established biofilm, thus indicating that this approach could be used to facilitate the effective treatment of intrinsically resistant biofilm infections.}, } @article {pmid27440915, year = {2017}, author = {Abbes, S and Amouri, I and Trabelsi, H and Neji, S and Sellami, H and Rahmouni, F and Makni, F and Rebai, T and Ayadi, A}, title = {Analysis of virulence factors and in vivo biofilm-forming capacity of Yarrowia lipolytica isolated from patients with fungemia.}, journal = {Medical mycology}, volume = {55}, number = {2}, pages = {193-202}, doi = {10.1093/mmy/myw028}, pmid = {27440915}, issn = {1460-2709}, mesh = {Adult ; Animals ; Biofilms/*growth & development ; Candida/isolation & purification/pathogenicity/physiology ; Catheters/microbiology ; Female ; Fungemia/*microbiology ; Hemolysin Proteins/analysis ; Humans ; Hydrolases/analysis ; Male ; Models, Animal ; Rats ; Virulence Factors/*analysis ; Yarrowia/isolation & purification/*pathogenicity/*physiology ; }, abstract = {Yarrowia lipolytica is ubiquitous in the environment, opportunistic, and might be considered as one of the causative agents of catheter-related candidemia. Our work aimed to study some virulence factors of Y. lipolytica such as hydrolases production and biofilm formation with comparison to the most frequent Candida specie in human disease. In sum, 58 clinical isolates of Y. lipolytica, 16 C. glabrata, and 12 C. albicans were collected from Intensive care unit (ICU). All were tested for enzymatic production and biofilm formation. All tested isolates of C. albicans and C. glabrata were able to degrade casein, and 98.2% of Y. lipolytica showed caseinase activity but no gelatinase activity was detected in all isolates. Y. lipolytica strains showed significantly lower (3.4%) in vitro phospholipase activity than C. albicans and C. glabrata (P < .05). No significant differences of the hemolytic activity were detected between the three species (P > .05). Concerning biofilm formation, and unlike the results obtained on polystyrene plate, the number of adhered and biofilm cultivable cells obtained by Y. lipolytica after 168 hours of catheter subcutaneous implantation is significantly greater and tends to be more compact and structured hyphal layer. Although C. albicans remains the most pathogenic yeast, development of selective ability of Y. lipolytica to adhere, to form a biofilm on catheter medical devices, and to produce phospholipase and hemolytic enzyme is of particular interest, and it is strongly recommended to be vigilant in the use of medical implanted medical devices, particularly in ICU.}, } @article {pmid27438340, year = {2016}, author = {Jaffar, N and Ishikawa, Y and Mizuno, K and Okinaga, T and Maeda, T}, title = {Mature Biofilm Degradation by Potential Probiotics: Aggregatibacter actinomycetemcomitans versus Lactobacillus spp.}, journal = {PloS one}, volume = {11}, number = {7}, pages = {e0159466}, pmid = {27438340}, issn = {1932-6203}, mesh = {Aggregatibacter actinomycetemcomitans/genetics/*growth & development ; Biofilms/growth & development ; Humans ; Lactobacillus/genetics/*growth & development ; Periodontal Diseases/microbiology/*therapy ; Probiotics/*therapeutic use ; Serogroup ; }, abstract = {The biofilm degradation of Aggregatibacter actinomycetemcomitans is essential as a complete periodontal disease therapy, and here we show the effects of potential probiotic bacteria such as Lactobacillus spp. for the biofilm of several serotypes of A. actinomycetemcomitans strains. Eight of the 13 species showed the competent biofilm degradation of ≥ 90% reduction in biofilm values in A. actinomycetemcomitans Y4 (serotype b) as well as four of the seven species for the biofilm of A. actinomycetemcomitans OMZ 534 (serotype e). In contrast, the probiotic bacteria did not have a big impact for the degradation of A. actinomycetemcomitans SUNY 75 (serotype a) biofilm. The dispersed A. actinomycetemcomitans Y4 cells through the biofilm detachment were still viable and plausible factors for the biofilm degradation were not due to the lactic acid and low pH conditions. The three enzymes, protease, lipase, and amylase may be responsible for the biofilm degradation; in particular, lipase was the most effective enzyme for the biofilm degradation of A. actinomycetemcomitans Y4 along with the protease activity which should be also important for the other serotypes. Remarkable lipase enzyme activities were detected from some of the potential probiotics and a supporting result using a lipase inhibitor presented corroborating evidence that lipase activity is one of the contributing factors for biofilm degradation outside of the protease which is also another possible factor for the biofilm of the other serotype of A. actinomycetemcomitans strains. On the other hand, the biofilm of A. actinomycetemcomitans SUNY 75 (serotype a) was not powerfully degraded by the lipase enzyme because the lipase inhibitor was slightly functional for only two of potential probiotics.}, } @article {pmid27438243, year = {2016}, author = {Li, X and Wei, Q and Tu, X and Zhu, Y and Chen, Y and Guo, L and Zhou, J and Sun, H}, title = {Effects of nutrient loading on Anabaena flos-aquae biofilm: biofilm growth and nutrient removals.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {2}, pages = {385-392}, doi = {10.2166/wst.2016.208}, pmid = {27438243}, issn = {0273-1223}, mesh = {Algal Proteins/metabolism ; Biofilms/*growth & development ; Dolichospermum flos-aquae/enzymology/growth & development/*physiology ; Eutrophication ; Microalgae/enzymology/growth & development/*physiology ; Oxidoreductases/metabolism ; Polysaccharides, Bacterial/metabolism ; Wastewater/*analysis ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Effects of three different nutrient loadings (low nutrient loading, medium nutrient loading and high nutrient loading, denoted as LNS, MNS and HNS, respectively) on the structure and functions of algal biofilm using Anabaena flos-aquae were investigated using synthetic wastewater. Nutrients removal efficiencies, biofilm thickness, microalgae dehydrogenase activity (DHA) and exopolysaccharide (EPS) productions were examined. Results showed that the changes of nutrient concentration were insignificant after 4 days of experiment for the case of HNS condition; 9 days for the case of MNS condition, and 6 days for the case of LNS condition, respectively. The biofilm thickness, nutrient removal efficiencies, algae DHA and EPS productions increased with the increase of nutrient loadings in synthetic wastewater. For the case of HNS condition, the microalgal biofilm exhibited the best performance in terms of C, N and P removal efficiencies, reaching the removal rates of 68.45, 3.56 and 1.61 mg·L(-1)·d(-1) for C, N, P, respectively. This was likely because, fact with the high nutrient loading, the high biological activity could be achieved, thus resulting in high nutrient removals. The thickness of the biofilm in HNS condition was 75 μm, which was closely related to EPS production. DHA and EPS concentrations were 7.24 and 1.8 × 10(-2) mg·mm(-2), respectively. It was also shown that apart from the nutrient loading, the structure and functions of microalgal biofilm were also influenced by other factors, such as illumination and temperature.}, } @article {pmid27439026, year = {2017}, author = {Vitali, A and Vavala, E and Marzano, V and Leone, C and Castagnola, M and Iavarone, F and Angiolella, L}, title = {Cell wall composition and biofilm formation of azoles-susceptible and -resistant Candida glabrata strains.}, journal = {Journal of chemotherapy (Florence, Italy)}, volume = {29}, number = {3}, pages = {164-172}, doi = {10.1080/1120009X.2016.1199507}, pmid = {27439026}, issn = {1973-9478}, mesh = {Adhesiveness ; Antifungal Agents/*pharmacology ; Azoles/pharmacology ; *Biofilms/drug effects ; Candida glabrata/drug effects/isolation & purification/*physiology ; Candidiasis/drug therapy/microbiology ; Carbohydrate Metabolism/drug effects ; Cell Wall/drug effects/*metabolism ; *Drug Resistance, Multiple, Fungal ; Fungal Polysaccharides/biosynthesis ; Fungal Proteins/*biosynthesis ; Gene Expression Regulation, Fungal/drug effects ; Hydrophobic and Hydrophilic Interactions ; Microbial Sensitivity Tests ; Mutation ; Proteomics/methods ; Species Specificity ; Surface Properties ; Triazoles/*pharmacology ; Two-Dimensional Difference Gel Electrophoresis ; }, abstract = {In the present study, three strains of Candida glabrata have been investigated to shed light on the mechanisms involved in azole resistance during adherence and biofilm formation. In particular, a clinical isolate, susceptible to azole-based drugs, DSY562 and two different resistant mutagenic strains deriving from DSY562, SFY114 and SFY115, have been analysed with different approaches for their cell wall composition and properties. A proteomic analysis revealed that the expression of six cell wall-related proteins and biofilm formation varied between the strains. The SFY114 and SFY115 strains resulted to be less hydrophobic than the susceptible parental counterpart DSY562, on the other hand they showed a higher amount in total cell wall polysaccharides fraction in the total cell wall. Accordingly to the results obtained from the hydrophobicity and adherence assays, in the resistant strain SFY115 the biofilm formation decreased compared to the parental strain DSY562. Finally, the total glucose amount in resistant SFY115 was about halved in comparison to other strains. Taken together all these data suggest that azole drugs may affect the cell wall composition of C. glabrata, in relation to the different pathogenic behaviours.}, } @article {pmid27438339, year = {2016}, author = {Konwar, A and Kalita, S and Kotoky, J and Chowdhury, D}, title = {Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {32}, pages = {20625-20634}, doi = {10.1021/acsami.6b07510}, pmid = {27438339}, issn = {1944-8252}, mesh = {Anti-Bacterial Agents ; Biofilms ; Chitosan ; Ferric Compounds ; Graphite ; Hydrogels ; Methicillin-Resistant Staphylococcus aureus ; *Nanocomposites ; Oxides ; Spectroscopy, Fourier Transform Infrared ; }, abstract = {We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis potentiality tests and MTT assays of the nanocomposite films indicated a noncytotoxic nature of the films, which conveyed the possibility of potential applications of these soft and tough films in biomedical as well as in the food industry.}, } @article {pmid27438223, year = {2016}, author = {Benigar, E and Zupančič Valant, A and Dogsa, I and Sretenovic, S and Stopar, D and Jamnik, A and Tomšič, M}, title = {Structure and Dynamics of a Model Polymer Mixture Mimicking a Levan-Based Bacterial Biofilm of Bacillus subtilis.}, journal = {Langmuir : the ACS journal of surfaces and colloids}, volume = {32}, number = {32}, pages = {8182-8194}, doi = {10.1021/acs.langmuir.6b02041}, pmid = {27438223}, issn = {1520-5827}, mesh = {Bacillus subtilis/*physiology ; *Biofilms ; DNA/*chemistry ; Fructans/*chemistry ; Rheology ; X-Ray Diffraction ; }, abstract = {In this paper, we report on the structure and dynamics of biologically important model polymer mixtures that mimic the extracellular polymeric matrix in native biofilm of Bacillus subtilis. This biofilm is rich in nonionic polysaccharide levan, but also contains other biopolymers such as DNA and proteins in small concentrations. Aiming to identify the contribution of each component to the formation of the biofilm, our investigations encompassed dynamic rheology, small-angle X-ray scattering, dynamic light scattering, microscopy, densitometry, and sound velocity measurements. As it turned out, this very powerful combination of techniques is able to provide solid results on the dynamical and structural aspects of the microbiologically and chemically complex biofilm formations. Macroscopic rheological measurements revealed that the addition of DNA to levan solution increased the viscosity, pseudoplasticity, and elasticity of the system. The addition of protein contributed similarly, but also increased the rigidity of the system. This confirms that the presence of minor biofilm components is essential for biofilm formation. DNA and proteins appear to confine levan molecules within their supramolecular structure and, in this way, restrict the role of levan to merely a filling agent. These findings were complemented by small-angle X-ray scattering data, which provided insight into the structure on a molecular scale. One of the essential goals of this work was to compare the structural properties of the native biofilm and synthetic biofilm mixture.}, } @article {pmid27436434, year = {2017}, author = {Doster, RS and Kirk, LA and Tetz, LM and Rogers, LM and Aronoff, DM and Gaddy, JA}, title = {Staphylococcus aureus Infection of Human Gestational Membranes Induces Bacterial Biofilm Formation and Host Production of Cytokines.}, journal = {The Journal of infectious diseases}, volume = {215}, number = {4}, pages = {653-657}, pmid = {27436434}, issn = {1537-6613}, support = {T32 HD060554/HD/NICHD NIH HHS/United States ; }, mesh = {Biofilms ; Chorioamnionitis/*immunology/microbiology ; Cytokines/*immunology ; Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Infant, Newborn ; Placenta/immunology/microbiology ; Pregnancy ; Pregnancy Complications, Infectious/*immunology/microbiology ; Premature Birth/immunology/microbiology ; Staphylococcal Infections/*immunology ; Staphylococcus aureus/immunology ; }, abstract = {Staphylococcus aureus, a metabolically flexible gram-positive pathogen, causes infections in a variety of tissues. Recent evidence implicates S. aureus as an emerging cause of chorioamnionitis and premature rupture of membranes, which are associated with preterm birth and neonatal disease. We demonstrate here that S. aureus infects and forms biofilms on the choriodecidual surface of explanted human gestational membranes. Concomitantly, S. aureus elicits the production of proinflammatory cytokines, which could ultimately perturb maternal-fetal tolerance during pregnancy. Therefore, targeting the immunological response to S. aureus infection during pregnancy could attenuate disease among infected individuals, especially in the context of antibiotic resistance.}, } @article {pmid27436387, year = {2016}, author = {Barakat, GI and Nabil, YM}, title = {Correlation of mupirocin resistance with biofilm production in methicillin-resistant Staphylococcus aureus from surgical site infections in a tertiary centre, Egypt.}, journal = {Journal of global antimicrobial resistance}, volume = {4}, number = {}, pages = {16-20}, doi = {10.1016/j.jgar.2015.11.010}, pmid = {27436387}, issn = {2213-7173}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; *Drug Resistance, Bacterial ; Egypt ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/*growth & development ; Microbial Sensitivity Tests ; Mupirocin/*pharmacology ; Prospective Studies ; Staphylococcal Infections/drug therapy ; Surgical Wound Infection/*microbiology ; Tertiary Care Centers ; }, abstract = {The aim of this study was to detect mupirocin-resistant isolates from pus/wound swabs taken postoperatively in a tertiary centre in Egypt and to determine their ability to form biofilm in order to establish its correlation with mupirocin resistance. This was a prospective study including 513pus/wound swabs from patients suffering from postoperative surgical site infections over the period July 2013-January 2015. Samples were cultured and isolates were identified by coagulase activity, DNase test, mannitol fermentation by mannitol salt agar followed by API Staph 32. Oxacillin agar screen test, agar dilution test for mupirocin, and mupA gene detection by PCR were performed for all methicillin-resistant Staphylococcus aureus (MRSA) isolates. Biofilm detection was carried out by the microtitre plate and Congo red agar methods. Of the 161 S. aureus isolates identified, 73 (45.3%) were MRSA, among which 82.2% were mupirocin-susceptible and 17.8% were mupirocin-resistant. Among the resistant isolates, 38.5% showed low-level resistance and 61.5% were high-level mupirocin-resistant. The mupA gene was detected in 75.0% of high-level mupirocin-resistant strains and in none of the low-level mupirocin-resistant strains. Among the mupirocin-susceptible isolates, 95.0% were biofilm-producers and 5.0% did not produce biofilm. All mupirocin-resistant isolates produced biofilm. Moreover, 15.3% of high-level mupirocin-resistant strains were negative for the mupA gene but showed evidence of biofilm formation. In conclusion, biofilm formation may be suggested to play a role in mupirocin resistance besides the presence of a genetic element encoding abnormal isoleucyl-tRNA synthetase, however further studies are needed to confirm these findings.}, } @article {pmid27435538, year = {2016}, author = {Kim, YJ and Lee, SH}, title = {Inhibitory Effect of Lactococcus lactis HY 449 on Cariogenic Biofilm.}, journal = {Journal of microbiology and biotechnology}, volume = {26}, number = {11}, pages = {1829-1835}, doi = {10.4014/jmb.1604.04008}, pmid = {27435538}, issn = {1738-8872}, mesh = {*Antibiosis ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Dental Caries/*microbiology/*prevention & control ; Glucosyltransferases/genetics/metabolism ; Humans ; Lactococcus lactis/*physiology ; Probiotics/metabolism ; Streptococcus mutans/enzymology/genetics/*physiology ; }, abstract = {Dental caries is caused by cariogenic biofilm, an oral biofilm including Streptococcus mutans. Recently, the prevention of dental caries using various probiotics has been attempted. Lactococcus lactis HY 449 is a probiotic bacterium. The aim of this study was to investigate the effect of L. lactis HY 449 on cariogenic biofilm and to analyze its inhibitory mechanisms. Cariogenic biofilm was formed in the presence or absence of L. lactis HY 449 and L. lactis ATCC 19435, and analyzed with a confocal laser microscope. The formation of cariogenic biofilm was reduced in cultures spiked with both L. lactis strains, and L. lactis HY 449 exhibited more inhibitory effects than L. lactis ATCC 19435. In order to analyze and to compare the inhibitory mechanisms, the antibacterial activity of the spent culture medium from both L. lactis strains against S. mutans was investigated, and the expression of glucosyltransferases (gtfs) of S. mutans was then analyzed by real-time RT-PCR. In addition, the sucrose fermentation ability of both L. lactis strains was examined. Both L. lactis strains showed antibacterial activity and inhibited the expression of gtfs, and the difference between both strains did not show. In the case of sucrose-fermenting ability, L. lactis HY 449 fermented sucrose but L. lactis ATCC 19435 did not. L. lactis HY 449 inhibited the uptake of sucrose and the gtfs expression of S. mutans, whereby the development of cariogenic biofilm may be inhibited. In conclusion, L. lactis HY 449 may be a useful probiotic for the prevention of dental caries.}, } @article {pmid27434592, year = {2016}, author = {Silva, S and Costa, EM and Horta, B and Calhau, C and Morais, RM and Pintado, MM}, title = {Anti-biofilm potential of phenolic acids: the influence of environmental pH and intrinsic physico-chemical properties.}, journal = {Biofouling}, volume = {32}, number = {8}, pages = {853-860}, doi = {10.1080/08927014.2016.1208183}, pmid = {27434592}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Biomass ; Escherichia coli/*drug effects/metabolism/physiology ; Hydrogen-Ion Concentration ; Hydroxybenzoates/chemistry/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/metabolism/physiology ; Microbial Sensitivity Tests ; Molecular Weight ; Staphylococcus epidermidis/*drug effects/metabolism/physiology ; }, abstract = {Phenolic acids are a particular group of small phenolic compounds which have exhibited some anti-biofilm activity, although the link between their activity and their intrinsic pH is not clear. Therefore, the present work examined the anti-biofilm activity (inhibition of biomass and metabolic activity) of phenolic acids in relation to the environmental pH, as well as other physico-chemical properties. The results indicate that, while Escherichia coli was not inhibited by the phenolic acids, both methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis were susceptible to the action of all phenolic acids, with the pH playing a relevant role in the activity: a neutral pH favored MRSE inhibition, while acidic conditions favored MRSA inhibition. Some links between molecular polarity and size were associated only with their potential as metabolic inhibitors, with the overall interactions hinting at a membrane-based mechanism for MRSA and a cytoplasmic effect for MRSE.}, } @article {pmid27434099, year = {2016}, author = {Zhang, X and Wang, X and Nie, K and Li, M and Sun, Q}, title = {Simulation of Bacillus subtilis biofilm growth on agar plate by diffusion-reaction based continuum model.}, journal = {Physical biology}, volume = {13}, number = {4}, pages = {046002}, doi = {10.1088/1478-3975/13/4/046002}, pmid = {27434099}, issn = {1478-3975}, mesh = {Agar ; Bacillus subtilis/growth & development/*physiology ; Biofilms/*growth & development ; Computer Simulation ; *Models, Biological ; }, abstract = {Various species of bacteria form highly organized spatially-structured aggregates known as biofilms. To understand how microenvironments impact biofilm growth dynamics, we propose a diffusion-reaction continuum model to simulate the formation of Bacillus subtilis biofilm on an agar plate. The extended finite element method combined with level set method are employed to perform the simulation, numerical results show the quantitative relationship between colony morphologies and nutrient depletion over time. Considering that the production of polysaccharide in wild-type cells may enhance biofilm spreading on the agar plate, we inoculate mutant colony incapable of producing polysaccharide to verify our results. Predictions of the glutamate source biofilm's shape parameters agree with the experimental mutant colony better than that of glycerol source biofilm, suggesting that glutamate is rate limiting nutrient for Bacillus subtilis biofilm growth on agar plate, and the diffusion-limited is a better description to the experiment. In addition, we find that the diffusion time scale is of the same magnitude as growth process, and the common-employed quasi-steady approximation is not applicable here.}, } @article {pmid27434252, year = {2016}, author = {Li, C and Yue, Z and Feng, F and Xi, C and Zang, H and An, X and Liu, K}, title = {A novel strategy for acetonitrile wastewater treatment by using a recombinant bacterium with biofilm-forming and nitrile-degrading capability.}, journal = {Chemosphere}, volume = {161}, number = {}, pages = {224-232}, doi = {10.1016/j.chemosphere.2016.07.019}, pmid = {27434252}, issn = {1879-1298}, mesh = {Acetonitriles/*metabolism ; Aminohydrolases/biosynthesis/*genetics/metabolism ; Bacillus subtilis/*genetics/*metabolism/physiology ; Bacterial Proteins/biosynthesis/genetics/metabolism ; Biofilms ; Bioreactors/microbiology ; Enzyme Induction ; Isopropyl Thiogalactoside/genetics/pharmacology ; Recombinant Proteins/pharmacology ; Rhodococcus/*genetics ; Waste Disposal, Fluid/methods ; Wastewater ; Water Pollutants, Chemical/*metabolism ; }, abstract = {There is a great need for efficient acetonitrile removal technology in wastewater treatment to reduce the discharge of this pollutant in untreated wastewater. In this study, a nitrilase gene (nit) isolated from a nitrile-degrading bacterium (Rhodococcus rhodochrous BX2) was cloned and transformed into a biofilm-forming bacterium (Bacillus subtilis N4) that expressed the recombinant protein upon isopropylthio-β-galactoside (IPTG) induction. The recombinant bacterium (B. subtilis N4-pHT01-nit) formed strong biofilms and had nitrile-degrading capability. Further testing demonstrated that biofilms formed by B. subtilis N4-pHT01-nit were highly resistant to loading shock from acetonitrile and almost completely degraded the initial concentration of acetonitrile (800 mg L(-1)) within 24 h in a moving bed biofilm reactor (MBBR) after operation for 35 d. The bacterial composition of the biofilm, identified by high-throughput sequencing, in a reactor in which the B. subtilis N4-pHT01-nit bacterium was introduced indicated that the engineered bacterium was successfully immobilized in the reactor and became dominant genus. This work demonstrates that an engineered bacterium with nitrile-degrading and biofilm-forming capacity can improve the degradation of contaminants in wastewater. This approach offers a novel strategy for enhancing the biological oxidation of toxic pollutants in wastewater.}, } @article {pmid27432830, year = {2016}, author = {Servetas, SL and Carpenter, BM and Haley, KP and Gilbreath, JJ and Gaddy, JA and Merrell, DS}, title = {Characterization of Key Helicobacter pylori Regulators Identifies a Role for ArsRS in Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {198}, number = {18}, pages = {2536-2548}, pmid = {27432830}, issn = {1098-5530}, support = {P30 DK058404/DK/NIDDK NIH HHS/United States ; T32 AI095202/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial/*physiology ; Helicobacter pylori/genetics/*physiology/ultrastructure ; Trans-Activators/genetics/*metabolism ; }, abstract = {UNLABELLED: Helicobacter pylori must be able to rapidly respond to fluctuating conditions within the stomach. Despite this need for constant adaptation, H. pylori encodes few regulatory proteins. Of the identified regulators, the ferric uptake regulator (Fur), the nickel response regulator (NikR), and the two-component acid response system (ArsRS) are each paramount to the success of this pathogen. While numerous studies have individually examined these regulatory proteins, little is known about their combined effect. Therefore, we constructed a series of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS. A growth curve analysis revealed minor variation in growth kinetics across the strains; these were most pronounced in the triple mutant and in strains lacking ArsS. Visual analysis showed that strains lacking ArsS formed large aggregates and a biofilm-like matrix at the air-liquid interface. Biofilm quantification using crystal violet assays and visualization via scanning electron microscopy (SEM) showed that all strains lacking ArsS or containing a nonphosphorylatable form of ArsR (ArsR-D52N mutant) formed significantly more biofilm than the wild-type strain. Molecular characterization of biofilm formation showed that strains containing mutations in the ArsRS pathway displayed increased levels of cell aggregation and adherence, both of which are key to biofilm development. Furthermore, SEM analysis revealed prevalent coccoid cells and extracellular matrix formation in the ArsR-D52N, ΔnikR ΔarsS, and Δfur ΔnikR ΔarsS mutant strains, suggesting that these strains may have an exacerbated stress response that further contributes to biofilm formation. Thus, H. pylori ArsRS has a previously unrecognized role in biofilm formation.

IMPORTANCE: Despite a paucity of regulatory proteins, adaptation is key to the survival of H. pylori within the stomach. While prior studies have focused on individual regulatory proteins, such as Fur, NikR, and ArsRS, few studies have examined the combined effect of these factors. Analysis of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS revealed a previously unrecognized role for the acid-responsive two-component system ArsRS in biofilm formation.}, } @article {pmid27430510, year = {2016}, author = {Wang, JH and Yang, CY and Fang, ST and Lu, J and Quan, CS}, title = {Inhibition of biofilm in Bacillus amyloliquefaciens Q-426 by diketopiperazines.}, journal = {World journal of microbiology & biotechnology}, volume = {32}, number = {9}, pages = {143}, pmid = {27430510}, issn = {1573-0972}, mesh = {Bacillus amyloliquefaciens/*drug effects/genetics/physiology ; Bacterial Proteins/*genetics ; Biofilms/drug effects ; Diketopiperazines/*pharmacology ; Down-Regulation ; Gene Expression Regulation, Bacterial/drug effects ; }, abstract = {Biofilm formation can make significant effects on bacteria habits and biological functions. In this study, diketopiperazines (DKPs) produced by strain of Bacillus amyloliquefaciens Q-426 was found to inhibit biofilm formed in the gas-liquid interface. Four kinds of DKPs were extracted from B. amyloliquefaciens Q-426, and we found that 0.04 mg ml(-1) DKPs could obviously inhibit the biofilm formation of the strain. DKPs produced by B. amyloliquefaciens Q-426 made a reduction on extracellular polymeric substance (EPS) components, polysaccharides, proteins, DNAs, etc. Real-time PCR was performed to determine that whether DKPs could make an obvious effect on the expression level for genes related to biofilm formation in the strain. The relative expression level of genes tasA, epsH, epsG and remB which related to proteins, extracellular matrix, and polysaccharides, were downregulated with 0.04 mg ml(-1) DKPs, while the expression level of nuclease gene nuc was significantly upregulated. The quantitative results of the mRNA expression level for these genes concerted with the quantitative results on EPS levels. All of the experimental results ultimately indicated that DKPs could inhibit the biofilm formation of the strain B. amyloliquefaciens Q-426.}, } @article {pmid27430359, year = {2017}, author = {Borghi, GN and Rodrigues, LP and Lopes, LM and Parisotto, TM and Steiner-Oliveira, C and Nobre-Dos-Santos, M}, title = {Relationship among α amylase and carbonic anhydrase VI in saliva, visible biofilm, and early childhood caries: a longitudinal study.}, journal = {International journal of paediatric dentistry}, volume = {27}, number = {3}, pages = {174-182}, doi = {10.1111/ipd.12249}, pmid = {27430359}, issn = {1365-263X}, mesh = {Biofilms/*growth & development ; Carbonic Anhydrases/*metabolism ; Child ; Child, Preschool ; Dental Caries/*enzymology ; Dental Caries Activity Tests ; Female ; Humans ; *Incisor ; Longitudinal Studies ; Male ; Maxilla ; Risk Assessment ; Saliva/*enzymology ; Statistics as Topic ; alpha-Amylases/*metabolism ; }, abstract = {AIM: This longitudinal study investigated the relationship among early childhood caries (ECC), α amylase, carbonic anhydrase VI (CA VI), and the presence of visible biofilm, besides detecting if these variables could predict risk for ECC.

DESIGN: One hundred children were divided into two groups: caries group (n = 45) and caries-free group (n = 55). Visible biofilm on maxillary incisors was recorded, followed by caries diagnosis in preschoolers at baseline and at follow-up. Saliva samples were collected, and activities of CA VI and α amylase were determined. Data normality was assessed by Shapiro-Wilk test and then Mann-Whitney, Spearman correlation, and chi-square tests followed by multiple logistic regression analysis (α = 0.05, 95% confidence interval).

RESULTS: CA VI activity was significantly higher in saliva of children with caries (P ≤ 0.05), and α amylase activity was significantly higher in saliva of caries-free children (P < 0.0001). Children with α amylase activity in saliva lower than 122.8 U/mL (OR = 3.33 P = 0.042) and visible biofilm on maxillary incisors (OR = 3.6 P = 0.009) were more likely to develop ECC than caries-free children. A negative correlation between caries and α amylase activity was found (P = 0.0008).

CONCLUSIONS: The presence of visible biofilm and low salivary activity of α amylase may be considered risk predictors for ECC.}, } @article {pmid27430253, year = {2016}, author = {Miller, CL and Romero, M and Karna, SL and Chen, T and Heeb, S and Leung, KP}, title = {RsmW, Pseudomonas aeruginosa small non-coding RsmA-binding RNA upregulated in biofilm versus planktonic growth conditions.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {155}, pmid = {27430253}, issn = {1471-2180}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; }, mesh = {Algorithms ; Amino Acid Sequence ; Bacterial Proteins/genetics/metabolism ; Base Sequence ; *Biofilms ; Chromosomes, Bacterial ; Gene Expression Regulation, Bacterial ; Mutation ; Pseudomonas aeruginosa/genetics/growth & development/metabolism/*physiology ; RNA, Bacterial/genetics/metabolism ; RNA, Small Untranslated/biosynthesis/*genetics/*metabolism ; RNA-Binding Proteins/biosynthesis/*genetics/*metabolism ; Transcriptional Activation ; Up-Regulation ; beta-Lactamases/genetics ; }, abstract = {BACKGROUND: Biofilm development, specifically the fundamentally adaptive switch from acute to chronic infection phenotypes, requires global regulators and small non-coding regulatory RNAs (sRNAs). This work utilized RNA-sequencing (RNA-seq) to detect sRNAs differentially expressed in Pseudomonas aeruginosa biofilm versus planktonic state.

RESULTS: A computational algorithm was devised to detect and categorize sRNAs into 5 types: intergenic, intragenic, 5'-UTR, 3'-UTR, and antisense. Here we report a novel RsmY/RsmZ-type sRNA, termed RsmW, in P. aeruginosa up-transcribed in biofilm versus planktonic growth. RNA-Seq, 5'-RACE and Mfold predictions suggest RsmW has a secondary structure with 3 of 7 GGA motifs located on outer stem loops. Northern blot revealed two RsmW binding bands of 400 and 120 bases, suggesting RsmW is derived from the 3'-UTR of the upstream hypothetical gene, PA4570. RsmW expression is elevated in late stationary versus logarithmic growth phase in PB minimal media, at higher temperatures (37 °C versus 28 °C), and in both gacA and rhlR transposon mutants versus wild-type. RsmW specifically binds to RsmA protein in vitro and restores biofilm production and reduces swarming in an rsmY/rsmZ double mutant. PA4570 weakly resembles an RsmA/RsmN homolog having 49 % and 51 % similarity, and 16 % and 17 % identity to RsmA and RsmN amino acid sequences, respectively. PA4570 was unable to restore biofilm and swarming phenotypes in ΔrsmA deficient strains.

CONCLUSION: Collectively, our study reveals an interesting theme regarding another sRNA regulator of the Rsm system and further unravels the complexities regulating adaptive responses for Pseudomonas species.}, } @article {pmid27429069, year = {2016}, author = {Rousseau, R and Santaella, C and Bonnafous, A and Achouak, W and Godon, JJ and Delia, ML and Bergel, A}, title = {Halotolerant bioanodes: The applied potential modulates the electrochemical characteristics, the biofilm structure and the ratio of the two dominant genera.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {112}, number = {}, pages = {24-32}, doi = {10.1016/j.bioelechem.2016.06.006}, pmid = {27429069}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/*microbiology ; *Biofilms ; Corrosion ; Electric Conductivity ; Electrochemistry ; Electrodes ; Gammaproteobacteria/chemistry/metabolism/*physiology ; Kinetics ; }, abstract = {The development of economically-efficient microbial electrochemical technologies remains hindered by the low ionic conductivity of the culture media used as the electrolyte. To overcome this drawback, halotolerant bioanodes were designed with salt marsh sediment used as the inoculum in electrolytes containing NaCl at 30 or 45g/L (ionic conductivity 7.0 or 10.4S·m(-1)). The bioanodes were formed at four different potentials -0.4, -0.2, 0.0 and 0.2V/SCE to identify the effect on the electrochemical kinetic parameters, the biofilm structures and the composition of the microbial communities. The bioanodes formed at -0.4V/SCE were largely dominated by Marinobacter spp. Voltammetry showed that they provided higher currents than the other bioanodes in the range of low potentials, but the maximum currents were limited by the poor surface colonization. The bioanodes formed at -0.2, 0.0 and 0.2V/SCE showed similar ratios of Marinobacter and Desulfuromonas spp. and higher values of the maximum current density. The combined analysis of kinetic parameters, biofilm structure and biofilm composition showed that Marinobacter spp., which ensured a higher electron transfer rate, were promising species for the design of halotolerant bioanodes. The challenge is now to overcome its limited surface colonization in the absence of Desulfuromonas spp.}, } @article {pmid27428076, year = {2016}, author = {Kumeria, T and Maher, S and Wang, Y and Kaur, G and Wang, L and Erkelens, M and Forward, P and Lambert, MF and Evdokiou, A and Losic, D}, title = {Naturally Derived Iron Oxide Nanowires from Bacteria for Magnetically Triggered Drug Release and Cancer Hyperthermia in 2D and 3D Culture Environments: Bacteria Biofilm to Potent Cancer Therapeutic.}, journal = {Biomacromolecules}, volume = {17}, number = {8}, pages = {2726-2736}, doi = {10.1021/acs.biomac.6b00786}, pmid = {27428076}, issn = {1526-4602}, mesh = {Animals ; Antibiotics, Antineoplastic/*administration & dosage/pharmacology ; Bacteria/growth & development ; Biofilms/growth & development ; Breast Neoplasms/pathology/*therapy ; Cell Culture Techniques ; Cell Survival/drug effects ; Cells, Cultured ; Combined Modality Therapy ; Doxorubicin/*administration & dosage/pharmacology ; Drug Carriers ; Drug Liberation ; Female ; Ferric Compounds/*chemistry ; *Fever ; Humans ; Macrophages/cytology/drug effects ; *Magnetics ; Mice ; *Nanowires ; }, abstract = {Iron oxide nanowires produced by bacteria (Mariprofundus ferrooxydans) are demonstrated as new multifunctional drug carriers for triggered therapeutics release and cancer hyperthmia applications. Iron oxide nanowires are obtained from biofilm waste in the bore system used to pump saline groundwater into the River Murray, South Australia (Australia) and processed into individual nanowires with extensive magnetic properties. The drug carrier capabilities of these iron oxide nanowires (Bac-FeOxNWs) are assessed by loading anticancer drug (doxorubicin, Dox) followed by measuring its elution under sustained and triggered release conditions using alternating magnetic field (AMF). The cytotoxicity of Bac-FeOxNWs assessed in 2D (96 well plate) and 3D (Matrigel) cell cultures using MDA-MB231-TXSA human breast cancer cells and mouse RAW 264.7 macrophage cells shows that these Bac-FeOxNWs are biocompatible even at concentrations as high as 250 μg/mL after 24 h of incubation. Finally, we demonstrate the capabilities of Bac-FeOxNWs as potential hyperthermia agent in 3D culture setup. Application of AMF increased the local temperature by 14 °C resulting in approximately 34% decrease in cell viability. Our results demonstrate that these naturally produced nanowires in the form of biofilm can efficiently act as drug carriers with triggered payload release and magnetothermal heating features for potential anticancer therapeutics applications.}, } @article {pmid27425219, year = {2017}, author = {Chenia, HY and Duma, S}, title = {Characterization of virulence, cell surface characteristics and biofilm-forming ability of Aeromonas spp. isolates from fish and sea water.}, journal = {Journal of fish diseases}, volume = {40}, number = {3}, pages = {339-350}, doi = {10.1111/jfd.12516}, pmid = {27425219}, issn = {1365-2761}, mesh = {Aeromonas/*pathogenicity/*physiology ; Animals ; *Bacterial Adhesion ; Biofilms/*growth & development ; Carps ; Catfishes ; Fish Diseases/*microbiology ; Gram-Negative Bacterial Infections/microbiology/*veterinary ; Seawater/microbiology ; Tilapia ; Virulence ; }, abstract = {Members of the genus Aeromonas are emerging human pathogens, causing a variety of extra-intestinal, systemic and gastrointestinal infections in both immunocompetent and immunocompromised persons. Aeromonas virulence is multifaceted and involves surface-associated molecules, motility, biologically active extracellular products and biofilm formation. Aeromonads, isolated from diverse freshwater fish species as well as sea water, were screened for biofilm formation, with varying physicochemical parameters including temperature, agitation and nutrient availability. Motility, cell surface characteristics (auto-aggregation, hydrophobicity and S layer), and extracellular virulence factor production (haemolysis, proteolysis, DNase production) were also assessed to identify potential associations with the biofilm phenotype. Biofilm formation was influenced by environmental conditions, with isolates preferentially forming biofilms in nutrient-rich media at 30 °C, although strong biofilm formation also occurred at 37 °C. Strong biofilm formation was observed for Aeromonas culicicola isolates following exposure to nutrient-rich conditions, while Aeromonas allosaccharophila isolates preferred nutrient-poor conditions for biofilm formation. Source-/species-specific correlations, ranging from weak to strong, were observed between biofilm formation and motility, cell surface characteristics and/or extracellular virulence factor production. Understanding the specific mechanisms by which Aeromonas species adhere to abiotic surfaces may aid in preventing and/or treating disease outbreaks in aquaculture systems and could lead to effective eradication of these fish pathogens.}, } @article {pmid27423128, year = {2016}, author = {Kniggendorf, AK and Nogueira, R and Kelb, C and Schadzek, P and Meinhardt-Wollweber, M and Ngezahayo, A and Roth, B}, title = {Confocal Raman microscopy and fluorescent in situ hybridization - A complementary approach for biofilm analysis.}, journal = {Chemosphere}, volume = {161}, number = {}, pages = {112-118}, doi = {10.1016/j.chemosphere.2016.06.096}, pmid = {27423128}, issn = {1879-1298}, mesh = {*Biofilms ; *In Situ Hybridization, Fluorescence ; *Microscopy, Confocal ; Sewage ; Spectrum Analysis, Raman ; }, abstract = {We combine confocal Raman microscopy (CRM) of wet samples with subsequent Fluorescent in situ hybridization (FISH) without significant limitations to either technique for analyzing the same sample of a microbial community on a cell-to-cell basis. This combination of techniques allows a much deeper, more complete understanding of complex environmental samples than provided by either technique alone. The minimalistic approach is based on laboratory glassware with micro-engravings for reproducible localization of the sample at cell scale combined with a fixation and de- and rehydration protocol for the respective techniques. As proof of concept, we analyzed a floc of nitrifying activated sludge, demonstrating that the sample can be tracked with cell-scale precision over different measurements and instruments. The collected information includes the microbial content, spatial shape, variant chemical compositions of the floc matrix and the mineral microparticles embedded within. In addition, the direct comparison of CRM and FISH revealed a difference in reported cell size due to the different cell components targeted by the respective technique. To the best of our knowledge, this is the first report of a direct cell-to-cell comparison of confocal Raman microscopy and Fluorescent in situ hybridization analysis performed on the same sample. An adaptation of the method to include native samples as a starting point is planned for the near future. The micro-engraving approach itself also opens up the possibility of combining other, functionally incompatible techniques as required for further in-depth investigations of low-volume samples.}, } @article {pmid27420160, year = {2016}, author = {Chatterjee, P and Ghangrekar, MM and Rao, S}, title = {Development of anammox process for removal of nitrogen from wastewater in a novel self-sustainable biofilm reactor.}, journal = {Bioresource technology}, volume = {218}, number = {}, pages = {723-730}, doi = {10.1016/j.biortech.2016.07.002}, pmid = {27420160}, issn = {1873-2976}, mesh = {Ammonia/*chemistry ; Anaerobiosis ; Bacteria/metabolism ; *Biofilms ; Bioreactors/*microbiology ; *Denitrification/drug effects ; Equipment Reuse ; Nitrogen/*isolation & purification/metabolism ; Oxygen/metabolism ; Sewage/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; }, abstract = {Effluent of an upflow anaerobic sludge blanket reactor was treated in a downflow rope-bed-biofilm-reactor (RBBR) to remove residual organic matter and nitrogen. Nitrogen removal was observed in phase 1 and phase 2 with and without aeration, respectively for 320days each. Organic matter, ammonia and total nitrogen removal efficiencies of 78±2%, 95±1% and 79±11% were obtained in phase 1 and 78±2%, 93±9% and 87±6% in phase 2, respectively. In phase 2, anammox bacteria had a specific anammox activity of 3.35gNm(-2)day(-1). Heme c concentration, sludge characteristics and reaction ratios of dissolved oxygen, alkalinity and pH corroborated contribution of anammox process. Using experimental results kinetic coefficients required for design of RBBR were estimated. Anammox gave more stable performance under varying nitrogen loading and this option is more sustainable for solving problem of nitrogen removal from sewage.}, } @article {pmid27420121, year = {2016}, author = {Wang, L and Kumeria, T and Santos, A and Forward, P and Lambert, MF and Losic, D}, title = {Iron Oxide Nanowires from Bacteria Biofilm as an Efficient Visible-Light Magnetic Photocatalyst.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {31}, pages = {20110-20119}, doi = {10.1021/acsami.6b06486}, pmid = {27420121}, issn = {1944-8252}, mesh = {Bacteria ; Biofilms ; Catalysis ; Ferric Compounds ; Kinetics ; Light ; *Nanowires ; }, abstract = {Naturally produced iron oxide nanowires by Mariprofundus ferrooxydans bacteria as biofilm are evaluated for their structural, chemical, and photocatalytic performance under visible-light irradiation. The crystal phase structure of this unique natural material presents a 1-dimensional (1D) nanowire-like geometry, which is transformed from amorphous to crystalline (hematite) by thermal annealing at high temperature without changing their morphology. This study systematically assesses the effect of different annealing temperatures on the photocatalytic activity of iron oxide nanowires produced by Mariprofundus ferrooxydans bacteria. The nanowires processed at 800 °C were the most optimal for photocatalytic applications degrading a model dye (rhodamine B) in less than an hour. These nanowires displayed excellent reusability with no significant loss of activity even after 6 cycles. Kinetic studies by using hydrogen peroxide (radical generator) and isopropyl alcohol (radical scavenger) suggest that OH• is the dominant photooxidant. These nanowires are naturally produced, inexpensive, highly active, stable, and magnetic and have the potential to be used for broad applications including environmental remediation, water disinfection, and industrial catalysis.}, } @article {pmid27413745, year = {2016}, author = {Li, X and Guan, C and He, Y and Wang, Y and Liu, X and Zhou, X}, title = {Effects of Total Alkaloids of Sophora alopecuroides on Biofilm Formation in Staphylococcus epidermidis.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {4020715}, pmid = {27413745}, issn = {2314-6141}, mesh = {Alkaloids/*administration & dosage ; Anti-Bacterial Agents/administration & dosage ; Apoptosis/drug effects ; Biofilms/drug effects/*growth & development ; Ciprofloxacin/*administration & dosage ; Erythromycin/administration & dosage ; Plant Extracts/administration & dosage ; Sophora/*chemistry/classification ; Species Specificity ; Staphylococcus epidermidis/cytology/*drug effects/*growth & development ; }, abstract = {Staphylococcus epidermidis (S. epidermidis) is an opportunistic pathogen with low pathogenicity and a cause of the repeated outbreak of bovine mastitis in veterinary clinical settings. In this report, a biofilm model of S. epidermidis was generated and the minimal inhibitory concentration (MIC) and sub-MIC (SMIC) on bacterial cultures were assessed for the following agents: total alkaloids of Sophora alopecuroides (TASA), ciprofloxacin (CIP), and erythromycin (ERY). The formation and characteristic parameters of biofilm were analyzed in terms of XTT assay, silver staining, and confocal laser scanning microscope (CLSM). Results showed that a sub-MIC of TASA could inhibit 50% biofilm of bacterial activity, while 250-fold MIC of CIP and ERY MICs only inhibited 50% and 47% of biofilm formation, respectively. All three agents could inhibit the biofilm formation at an early stage, but TASA showed a better inhibitory effect on the late stage of biofilm thickening. A morphological analysis using CLSM further confirmed the destruction of biofilm by these agents. These results thus suggest that TASA has an inhibitory effect on biofilm formation of clinic S. epidermidis, which may be a potential agent warranted for further study on the treatment prevention of infection related to S. epidermidis in veterinary clinic.}, } @article {pmid27413588, year = {2016}, author = {Sahni, K and Khashai, F and Forghany, A and Krasieva, T and Wilder-Smith, P}, title = {Exploring Mechanisms of Biofilm Removal.}, journal = {Dentistry (Sunnyvale, Calif.)}, volume = {6}, number = {4}, pages = {}, pmid = {27413588}, issn = {2161-1122}, support = {P41 EB015890/EB/NIBIB NIH HHS/United States ; R03 EB014852/EB/NIBIB NIH HHS/United States ; }, abstract = {OBJECTIVE: The goal of this study was to evaluate the effects of a novel anti-plaque formulation on oral biofilm removal. Specific aim was to elucidate the role of 2 potentially complementary mechanisms on dental biofilm removal using EPIEN Dental Debriding Solution (EDDS) like desiccating action leading to denaturation and destabilization of plaque and mechanical removal of destabilized plaque through forceful rinsing action.

MATERIALS AND METHODS: 25 extracted teeth, after routine debriding and cleaning, underwent standard biofilm incubation model over 4 days. Then samples were randomly divided into 5 groups of 5 teeth each, treated and stained with GUM[®]Red-Cote[®] plaque disclosing solution and imaged. Samples were subsequently treated with HYBENX[®] Oral Decontaminant. Group 1 samples were treated with a standardized "static" water dip exposure following biofilm incubation. Samples in Group 2 were given a standardized "dynamic" exposure to a dental high pressure air/water syringe for 20 s. Group 3 samples were exposed to a standardized "static" application of test agent (30 s dip rinse) followed by a standardized "static" water rinse (30 s dip rinse). Samples in Group 4 were given both the standardized "static" application of test formulation followed by the standardized "dynamic" exposure to a dental high pressure air/water syringe. Finally, samples in Group 5 were treated with a standardized "dynamic" application of test agent (20 s high pressure syringe at 10 ml/s) followed by the standardized "dynamic" exposure to a dental high pressure air/water syringe.

RESULTS: The MPM images demonstrated that the water dip treatment resulted in the persistence of an almost continuous thick layer of biofilm coverage on the tooth surface. Similarly, test agent dip treatment followed by water dip only removed a few patches of biofilm, with the majority of the tooth surface remaining covered by an otherwise continuous layer of biofilm. Samples exposed to air/water spray alone showed some disruption of the biofilm, leaving residual patches of biofilm that varied considerably in size. Test agent dip treatment followed by air/water spray broke up the continuous layer of biofilm leaving only very small, thin scattered islands of biofilm. Finally, the dynamic test agent spray followed by air/water spray removed the biofilm almost entirely, with evidence of only very few small, thin residual biofilm islands.

CONCLUSION: These studies demonstrate that test agent desiccant effect alone causes some disruption of dental biofilm. Additional dynamic rinsing is needed to achieve complete removal of dental biofilm.}, } @article {pmid27412380, year = {2016}, author = {Brandes, J and Kuhajek, JM and Goodwin, E and Wood, SA}, title = {Molecular Characterisation and Co-cultivation of Bacterial Biofilm Communities Associated with the Mat-Forming Diatom Didymosphenia geminata.}, journal = {Microbial ecology}, volume = {72}, number = {3}, pages = {514-525}, pmid = {27412380}, issn = {1432-184X}, mesh = {Bacteria/classification/*genetics/growth & development/isolation & purification ; Bacterial Physiological Phenomena/genetics ; Base Sequence ; *Biofilms ; Carnobacterium/growth & development ; Cell Adhesion ; *Coculture Techniques ; DNA, Bacterial ; Diatoms/*genetics/growth & development/*microbiology/physiology ; Fresh Water/*microbiology ; High-Throughput Nucleotide Sequencing ; New Zealand ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Rivers/microbiology ; Sphingobacterium ; Water Microbiology ; }, abstract = {Didymosphenia geminata (Lyngbye) M. Schmidt is a stalked freshwater diatom that is expanding its range globally. In some rivers, D. geminata forms thick and expansive polysaccharide-dominated mats. Like other stalked diatoms, D. geminata cells attach to the substratum with a pad of adhesive extracellular polymeric substance. Research on D. geminata and other diatoms suggests that bacterial biofilm composition may contribute to successful attachment. The aim of this study was to investigate the composition and role of bacterial biofilm communities in D. geminata attachment and survival. Bacterial biofilms were collected at four sites in the main stem of a river (containing D. geminata) and in four tributaries (free of D. geminata). Samples were characterised using automated rRNA intergenic spacer analysis and high-throughput sequencing (HTS). Mat-associated bacteria were isolated and their effect on the early establishment of D. geminata cells assessed using co-culturing experiments. ARISA and HTS data showed differences in bacterial communities between samples with and without D. geminata at two of the four sites. Samples with D. geminata had a higher relative abundance of Sphingobacteria (p < 0.01) and variability in community composition was reduced. Analysis of the 76 bacteria isolated from the mat revealed 12 different strains representing 8 genera. Co-culturing of a Carnobacterium sp. with D. geminata reduced survival (p < 0.001) and attachment (p < 0.001) of D. geminata. Attachment was enhanced by Micrococcus sp. and Pseudomonas sp. (p < 0.001 and p < 0.01, respectively). These data provide evidence that bacteria play a role in the initial attachment and on-going survival of D. geminata, and may partly explain observed distribution patterns.}, } @article {pmid27411324, year = {2017}, author = {Sánchez-Gómez, S and Martínez-de-Tejada, G}, title = {Antimicrobial Peptides as Anti-biofilm Agents in Medical Implants.}, journal = {Current topics in medicinal chemistry}, volume = {17}, number = {5}, pages = {590-603}, doi = {10.2174/1568026616666160713141439}, pmid = {27411324}, issn = {1873-4294}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Peptides/*pharmacology ; Prostheses and Implants/*microbiology ; }, abstract = {Biofilm-associated infections constitute a daunting threat to human health, since these pathologies increase patient mortality and morbidity, resulting in prolonged hospitalization periods and heavy economic losses. Moreover, these infections contribute to the increasing emergence and dissemination of antibiotic resistance in hospitals and in the community. Although biofilm-associated microorganisms can proliferate in healthy tissue, abiotic surfaces like those of medical implants greatly increase the likelihood of biofilm formation in the host. Due to their broad spectrum of bactericidal activity against multi-drug resistant microorganisms including metabolically inactive cells, antimicrobial peptides (AMPs) have great potential as anti-biofilm agents. In fact, a clinically available AMP, polymyxin E (colistin), frequently constitutes the drug of last recourse in biofilm-associated infections (e.g. cystic fibrosis) when resistance to all the other drugs arises. In this article, we outline the main strategies under development to combat biofilm-associated infections with an emphasis in the prevention of microbial colonization of medical implants. These approaches include the use of AMPs both for the development of anti-adhesive surface coatings and to kill biofilm-forming cells either on contact or via controlled release (leaching surfaces). Although in vitro results for all these applications are very encouraging, further research is needed to improve the anti-biofilm activity of these coatings in vivo. The possibility of exploiting the antibiotic potentiating activity of some AMPs and to combine several anti-biofilm mechanisms in tandem targeting the biofilm formation process at different stages is also discussed.}, } @article {pmid27405358, year = {2016}, author = {Wang, A and Wang, Q and Kudinha, T and Xiao, S and Zhuo, C}, title = {Effects of Fluoroquinolones and Azithromycin on Biofilm Formation of Stenotrophomonas maltophilia.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {29701}, pmid = {27405358}, issn = {2045-2322}, mesh = {Azithromycin/*pharmacology ; Biofilms/*drug effects/growth & development ; Fluoroquinolones/*pharmacology ; Stenotrophomonas maltophilia/*physiology ; }, abstract = {Stenotrophomonas maltophilia is an opportunistic pathogen that causes respiratory and urinary tract infections, as well as wound infections in immunocompromised patients. This pathogen is difficult to treat due to increased resistance to many antimicrobial agents. We investigated the in vitro biofilm formation of S. maltophilia, including effects of fluoroquinolones (FQs) and azithromycin on biofilm formation. The organism initiated attachment to polystyrene surfaces after a 4 h incubation period, and reached maximal growth at 18-24 h. In the presence of FQs (moxifloxacin, levofloxacin or ciprofloxacin), the biofilm biomass was significantly reduced (P < 0.05). A lower concentration of moxifloxacin (10 μg/mL) exhibited a better inhibiting effect on biofilm formation than 100 μg/mL (P < 0.01), but with no difference in effect compared to the 50 μg/mL concentration (P > 0.05). However, the inhibitory effects of 10 μg/mL of levofloxacin or ciprofloxacin were slightly less pronounced than those of the higher concentrations. A combination of azithromycin and FQs significantly reduced the biofilm inhibiting effect on S. maltophilia preformed biofilms compared to azithromycin or FQs alone. We conclude that early use of clinically acceptable concentrations of FQs, especially moxifloxacin (10 μg/mL), may possibly inhibit biofilm formation by S. maltophilia. Our study provides an experimental basis for a possible optimal treatment strategy for S. maltophilia biofilm-related infections.}, } @article {pmid27405227, year = {2016}, author = {Jiang, Q and Stamatova, I and Kainulainen, V and Korpela, R and Meurman, JH}, title = {Interactions between Lactobacillus rhamnosus GG and oral micro-organisms in an in vitro biofilm model.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {149}, pmid = {27405227}, issn = {1471-2180}, mesh = {Actinobacteria/physiology ; Adhesins, Bacterial ; Aggregatibacter/physiology ; Biofilms/*growth & development ; Candida albicans/physiology ; Durapatite/chemistry ; Fusobacterium nucleatum/physiology ; Hydrogen-Ion Concentration ; Lacticaseibacillus rhamnosus/*physiology ; Microbial Consortia ; Microbial Interactions ; Microbial Viability ; Microscopy, Confocal ; Mouth/*microbiology ; Probiotics/pharmacology ; Saliva/microbiology ; Streptococcus mutans/physiology ; Streptococcus sanguis/physiology ; }, abstract = {BACKGROUND: Probiotics have shown favourable properties in maintaining oral health. By interacting with oral microbial communities, these species could contribute to healthier microbial equilibrium. This study aimed to investigate in vitro the ability of probiotic Lactobacillus rhamnosus GG (L.GG) to integrate in oral biofilm and affect its species composition. Five oral strains, Streptococcus mutans, Streptococcus sanguinis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum and Candida albicans were involved. The group setup included 6 mono-species groups, 3 dual-species groups (L.GG + S. mutans/S. sanguinis/C. albicans), and 4 multi-species groups (4/5 species and 4/5 species + L.GG, 4 species were all the tested strains except S. mutans). Cell suspensions of six strains were pooled according to the group setup. Biofilms were grown on saliva-coated hydroxyapatite (HA) discs at 37 °C in anaerobic conditions for 64.5 h. Biofilm medium was added and refreshed at 0, 16.5, and 40.5 h. The pH of spent media was measured. Viable cells of the 16.5 h and 64.5 h biofilms were counted. 64.5 h biofilms were stained and scanned with confocal laser scanning microscopy.

RESULTS: Our results showed that L.GG and S. mutans demonstrated stronger adhesion ability than the other strains to saliva-coated HA discs. L.GG, C. albicans, S. mutans and F. nucleatum, with poor ability to grow in mono-species biofilms demonstrated better abilities of adhesion and reproduction in dual- and/or multi-species biofilms. L.GG slightly suppressed the growth of C. albicans in all groups, markedly weakened the growth of S. sanguinis and F. nucleatum in 4sp + L.GG group, and slightly reduced the adhesion of S. mutans in L.GG+ S. mutans group.

CONCLUSIONS: To conclude, in this in vitro model L.GG successfully integrated in all oral biofilms, and reduced the counts of S. sanguinis and C. albicans and lowered the biofilm-forming ability of F. nucleatum, but only slightly reduced the adhesion of S. mutans. C. albicans significantly promoted the growth of L.GG.}, } @article {pmid27404808, year = {2016}, author = {Donner, J and Reck, M and Bergmann, S and Kirschning, A and Müller, R and Wagner-Döbler, I}, title = {The biofilm inhibitor Carolacton inhibits planktonic growth of virulent pneumococci via a conserved target.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {29677}, pmid = {27404808}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Macrolides/*pharmacology ; Myxococcales/drug effects/metabolism ; Plankton/*drug effects ; Pneumococcal Infections/drug therapy ; Streptococcus mutans/*drug effects/metabolism ; Streptococcus pneumoniae/*drug effects/metabolism ; }, abstract = {New antibacterial compounds, preferentially exploiting novel cellular targets, are urgently needed to fight the increasing resistance of pathogens against conventional antibiotics. Here we demonstrate that Carolacton, a myxobacterial secondary metabolite previously shown to damage Streptococcus mutans biofilms, inhibits planktonic growth of Streptococcus pneumoniae TIGR4 and multidrug-resistant clinical isolates of serotype 19A at nanomolar concentrations. A Carolacton diastereomer is inactive in both streptococci, indicating a highly specific interaction with a conserved cellular target. S. mutans requires the eukaryotic-like serine/threonine protein kinase PknB and the cysteine metabolism regulator CysR for susceptibility to Carolacton, whereas their homologues are not needed in S. pneumoniae, suggesting a specific function for S. mutans biofilms only. A bactericidal effect of Carolacton was observed for S. pneumoniae TIGR4, with a reduction of cell numbers by 3 log units. The clinical pneumonia isolate Sp49 showed immediate growth arrest and cell lysis, suggesting a bacteriolytic effect of Carolacton. Carolacton treatment caused a reduction in membrane potential, but not membrane integrity, and transcriptome analysis revealed compensatory reactions of the cell. Our data show that Carolacton might have potential for treating pneumococcal infections.}, } @article {pmid27403051, year = {2016}, author = {Díaz-Garrido, N and Lozano, C and Giacaman, RA}, title = {Frequency of sucrose exposure on the cariogenicity of a biofilm-caries model.}, journal = {European journal of dentistry}, volume = {10}, number = {3}, pages = {345-350}, pmid = {27403051}, issn = {1305-7456}, abstract = {OBJECTIVE: Although sucrose is considered the most cariogenic carbohydrate in the human diet, the question of how many exposures are needed to induce damage on the hard dental tissues remains unclear. To approach this question, different frequencies of daily sucrose exposure were tested on a relevant biological caries model.

MATERIALS AND METHODS: Biofilms of the Streptococcus mutans were formed on enamel slabs and exposed to cariogenic challenges with 10% sucrose for 5 min at 0, 1, 3, 5, 8, or 10 times per day. After 5 days, biofilms were retrieved to analyze biomass, protein content, viable bacteria, and polysaccharide formation. Enamel demineralization was evaluated by percentage of microhardness loss (percentage surface hardness loss [%SHL]).

RESULTS: Biomass, protein content, polysaccharide production, acidogenicity of the biofilm, and %SHL proportionally increased with the number of daily exposures to sucrose (P < 0.05). One daily sucrose exposure was enough to induce 20% more demineralization than the negative unexposed control. Higher frequencies induced greater demineralization and more virulent biofilms, but eight and ten exposures were not different between them in most of the analyzed variables (P > 0.05).

CONCLUSIONS: Higher sucrose exposure seems to increase cariogenicity, in a frequency-dependent manner, by the modification of bacterial virulent properties.}, } @article {pmid27402785, year = {2016}, author = {Coenye, T and Bjarnsholt, T}, title = {Editorial: The complexity of microbial biofilm research-an introduction to the third thematic issue on biofilms.}, journal = {Pathogens and disease}, volume = {74}, number = {7}, pages = {}, doi = {10.1093/femspd/ftw053}, pmid = {27402785}, issn = {2049-632X}, mesh = {*Biofilms ; *Microbiology ; *Research ; }, } @article {pmid27402781, year = {2016}, author = {Singh, R and Sahore, S and Kaur, P and Rani, A and Ray, P}, title = {Penetration barrier contributes to bacterial biofilm-associated resistance against only select antibiotics, and exhibits genus-, strain- and antibiotic-specific differences.}, journal = {Pathogens and disease}, volume = {74}, number = {6}, pages = {}, doi = {10.1093/femspd/ftw056}, pmid = {27402781}, issn = {2049-632X}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Bacterial Physiological Phenomena ; *Biofilms/drug effects ; Drug Resistance, Bacterial ; Selection, Genetic/*drug effects ; }, abstract = {Bacterial biofilms are implicated in a wide range of implant-based and chronic infections. These infections are often associated with adverse therapeutic outcomes, owing to the decreased antibiotic susceptibility of biofilms compared with their planktonic counterparts. This altered biofilm susceptibility has been attributed to multiple factors, including a reduced antibiotic penetration. Although several studies have addressed the role of penetration barrier in biofilm-associated drug resistance, it remains inconclusive. This study was done to elucidate antibiotic penetration through biofilms formed by Staphylococcus aureus, S. epidermidis, Escherichia coli and Klebsiella pneumoniae, using an agar disk diffusion assay. Penetration capacity of six antimicrobial drugs from different classes (β-lactams, aminoglycosides, tetracyclines, phenicols, fluoroquinolones and glycopeptides) through biofilms formed by standard strains and clinical isolates from catheter-related bloodstream infections (CRBSI) was elucidated by measuring their growth-inhibition zones in lawn cultures on Mueller-Hinton agar, following diffusion of an antibiotic from an overlying disk through their biofilm to the agar medium. Penetration of only select antimicrobials (vancomycin and chloramphenicol) was hindered through biofilms. There was considerable variation in biofilm-permeating capacity depending upon the genus, strain/CRBSI isolate and antibiotic tested. Furthermore, antibiotics failed to kill the biofilm cells independent of penetration, indicating that other factors contributed substantially to biofilm resistance.}, } @article {pmid27401574, year = {2016}, author = {Meeker, DG and Beenken, KE and Mills, WB and Loughran, AJ and Spencer, HJ and Lynn, WB and Smeltzer, MS}, title = {Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {10}, pages = {5688-5694}, pmid = {27401574}, issn = {1098-6596}, support = {P30 GM103450/GM/NIGMS NIH HHS/United States ; T32 GM106999/GM/NIGMS NIH HHS/United States ; UL1 TR000039/TR/NCATS NIH HHS/United States ; R01 AI119380/AI/NIAID NIH HHS/United States ; }, mesh = {Aminoglycosides/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Catheter-Related Infections/drug therapy/microbiology ; Drug Evaluation, Preclinical/methods ; Drug Resistance, Multiple, Bacterial/drug effects ; Glycopeptides/pharmacology ; Lipoglycopeptides ; Methicillin-Resistant Staphylococcus aureus/*drug effects/pathogenicity ; Mice ; Microbial Sensitivity Tests ; Teicoplanin/analogs & derivatives/pharmacology ; }, abstract = {We used in vitro and in vivo models of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) in the specific context of an established biofilm. The results demonstrated that, under in vitro conditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when tested in vivo in a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associated S. aureus infections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.}, } @article {pmid27401077, year = {2017}, author = {De Vecchi, E and Bottagisio, M and Bortolin, M and Toscano, M and Lovati, AB and Drago, L}, title = {Improving the Bacterial Recovery by Using Dithiothreitol with Aerobic and Anaerobic Broth in Biofilm-Related Prosthetic and Joint Infections.}, journal = {Advances in experimental medicine and biology}, volume = {973}, number = {}, pages = {31-39}, doi = {10.1007/5584_2016_51}, pmid = {27401077}, issn = {0065-2598}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Dithiothreitol/*pharmacology ; Humans ; Propionibacterium acnes/*drug effects/physiology ; Prostheses and Implants/adverse effects/microbiology ; Prosthesis-Related Infections/etiology/microbiology/*prevention & control ; Staphylococcus aureus/drug effects/physiology ; }, abstract = {Biofilm-related infections are serious complications in the orthopaedic prosthetic field and an accurate, quick microbiological diagnosis is required to set up a specific antimicrobial therapy. It is well known that the diagnosis of these infections remains difficult due to the bacterial embedding within the biofilm matrix on the implant surfaces. Recently, the use of DL-dithiothreitol (DTT) has been proved effective in biofilm detachment from orthopaedic devices.The purpose of the study is to evaluate the efficacy of two DTT solutions enriched with specific broths for aerobic or anaerobic bacteria to dislodge pathogens from the biofilm, while supporting the bacterial recovery and viability. To do this, different experimental solutions were tested for efficacy and stability on strong biofilm producers: S. aureus and P. acnes. Mainly, we evaluate the capability of DTT dissolved in saline solution, brain heart infusion or thioglycollate broth to support the bacterial detachment from prosthetic materials and bacterial growth at different time points and storage conditions.We demonstrated that the use of DTT enriched with specific bacterial broths could be a suitable approach to optimize the bacterial detachment, recovery, growth and viability in the diagnosis of biofilm-related infections developed on orthopaedic prosthetic devices.}, } @article {pmid27400694, year = {2017}, author = {Somogyi-Ganss, E and Chambers, MS and Lewin, JS and Tarrand, JJ and Hutcheson, KA}, title = {Biofilm on the tracheoesophageal voice prosthesis: considerations for oral decontamination.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {274}, number = {1}, pages = {405-413}, pmid = {27400694}, issn = {1434-4726}, support = {P30 CA016672/CA/NCI NIH HHS/United States ; R01 DE025248/DE/NIDCR NIH HHS/United States ; R03 CA188162/CA/NCI NIH HHS/United States ; R56 DE025248/DE/NIDCR NIH HHS/United States ; R01 CA160880/CA/NCI NIH HHS/United States ; }, mesh = {Adult ; Aged ; Aged, 80 and over ; Bacterial Infections/diagnosis/etiology/prevention & control ; *Biofilms ; *Decontamination ; Female ; Humans ; Laryngeal Neoplasms/*surgery ; Laryngectomy ; Larynx, Artificial/*microbiology ; Male ; Middle Aged ; Prosthesis Implantation ; Prosthesis-Related Infections/diagnosis/etiology/prevention & control ; Retrospective Studies ; }, abstract = {The tracheoesophageal puncture (TEP) restores verbal communication after total laryngectomy using a one-way valved voice prosthesis (VP). Microbial colonization can shorten VP device life. Our aims were to investigate patterns of prosthetic and oral colonization, and record changes in VP device life after targeted decontamination. We conducted a retrospective review of TEP clinic patients who underwent microbial analysis of the VP between 01/2003 and 07/2013. Two subgroups were analyzed: (1) patients with microbial analysis of the VP and the mouth were analyzed to identify patterns of common contamination, and (2) patients who were prescribed targeted oral decontamination on the basis of the microbial analysis of the VP were analyzed to evaluate effects on device life. Among 42 patients, 3 patients had only fungal, 5 only bacterial, and 33 had polyspecies fungal and bacterial colonization. In the TEP-oral microflora subgroup (n = 15), 7 had common microorganisms in the mouth and on the VP. Among the decontamination subgroup (n = 23), 6 patients received broad spectrum rinse, 16 antifungal agents and 13 antibiotics, or a combination thereof. After targeted decontamination, the median device life of prostheses improved from 7.89 to 10.82 weeks (p = 0.260). The majority of patients with a suboptimal VP device life in this pilot had polyspecies bacterial and fungal colonization. VPs rarely had fungal contamination alone (3 %), and non-albicans fungal species were more common than expected. For these reasons, we are exploring the use of targeted decontamination regimens that were associated with 1.4-fold improvement in VP duration.}, } @article {pmid27400164, year = {2015}, author = {Zhao, L and Ashraf, MA}, title = {Influence of Silver-hydroxyapatite Nanocomposite Coating on Biofilm Formation of Joint Prosthesis and Its Mechanism.}, journal = {The West Indian medical journal}, volume = {64}, number = {5}, pages = {506-513}, pmid = {27400164}, issn = {0043-3144}, abstract = {BACKGROUND: The main reason for biomaterial related refractory infections is biofilm formation caused by bacterial adhesion on the surface of materials. Silver-hydroxyapatite (Ag/HA) nanocomposite coating can inhibit the formation of biofilm, but its mechanism is not clear.

MATERIAL AND METHOD: In order to clarify the mechanism, the amounts of biofilm on the Ag/HA composite coating and HA coating were determined, the release rates of silver nanoparticles in simulated body fluid (SBF) were detected by atomic absorption spectrometry, and the expression values of atlE, fbe, sap, iapB genes of Staphylococcus aureus were studied when they grew on Ag/HA composite coating and HA coating.

RESULTS: The amount of the biofilm on the Ag/HA composite coating was significantly less than that on the HA coating, and the bacterial adhesion was decreased. The silver nanoparticles were released continuously in SBF and the release rate decreased gradually with time. The expression values of atlE, fbe and sap were high in the initial stage of adhesion and the expression value of iapB was high in the colonies-gathering stage in the control group, but they were all significantly inhibited in the presence of Ag.

CONCLUSION: These results indicated that the main antibacterial effect of Ag/HA composite coating was achieved by the release of silver nanoparticles. The addition of Ag inhibited the expression of genes related to biofilm formation, which in turn inhibited the formation of biofilms. This provided theoretical support for the clinical application of Ag/HA composite coating.}, } @article {pmid27400059, year = {2016}, author = {Hou, J and You, G and Xu, Y and Wang, C and Wang, P and Miao, L and Dai, S and Lv, B and Yang, Y}, title = {Antioxidant enzyme activities as biomarkers of fluvial biofilm to ZnO NPs ecotoxicity and the Integrated Biomarker Responses (IBR) assessment.}, journal = {Ecotoxicology and environmental safety}, volume = {133}, number = {}, pages = {10-17}, doi = {10.1016/j.ecoenv.2016.06.014}, pmid = {27400059}, issn = {1090-2414}, mesh = {Antioxidants/*analysis ; Biofilms/*drug effects ; Biomarkers/*analysis ; Catalase/analysis ; Glutathione Peroxidase/analysis ; Glutathione Reductase/analysis ; Metal Nanoparticles/*toxicity ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Oxidation-Reduction ; Oxidoreductases/*analysis ; Reactive Oxygen Species/analysis ; Superoxide Dismutase/analysis ; Time Factors ; Zinc Oxide/*toxicity ; }, abstract = {The presence of ZnO nanoparticles (ZnO NPs) in natural waters has raised concerns about their environmental impacts, but the potential influences of ZnO NPs on fluvial biofilm have not been reported. In this study, the utility of antioxidant enzyme activities (AEA) as biomarkers of fluvial biofilm to ZnO NPs toxicity and a method that combines AEA into an index of "Integrated Biomarker Responses (IBR)" were studied. Compared with the absence of ZnO NPs, scanning electron microscopy (SEM) images revealed that a large amount of ZnO NPs were adsorbed onto biofilm and these NPs exerted adverse effects on the viability of bacteria in biofilm. The production of reactive oxygen species (ROS) with high concentrations (30 and 100mg/L) of ZnO NPs exposure reached to 184% and 244% of the control, while no cell leakage and membrane damage were observed. After exposure to ZnO NPs for 0.25 and 3 days, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR), glutathione peroxidase (GSH-Px) were significantly increased, respectively. At the end of exposure period (21 days), the AEA with the presence of 1mg/L ZnO NPs exposure were comparable to the control, while most of those in high concentrations of ZnO NPs were decreased. The results of IBR showed that the biofilm can adapt to 1mg/L ZnO NPs exposure, while be seriously damaged by 30 and 100mg/L ZnO NPs after 3 and 0.25 days. IBR can be used as an appropriate evaluation system of the toxicity effects of ZnO NPs on fluvial biofim.}, } @article {pmid27396378, year = {2016}, author = {Patel, SS and Aruni, W and Inceoglu, S and Akpolat, YT and Botimer, GD and Cheng, WK and Danisa, OA}, title = {A comparison of Staphylococcus aureus biofilm formation on cobalt-chrome and titanium-alloy spinal implants.}, journal = {Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia}, volume = {31}, number = {}, pages = {219-223}, doi = {10.1016/j.jocn.2016.03.013}, pmid = {27396378}, issn = {1532-2653}, mesh = {Biofilms/*growth & development ; *Chromium Alloys ; Humans ; Orthopedic Procedures/instrumentation ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*microbiology ; Spine/surgery ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*physiology ; *Titanium ; }, abstract = {The use of cobalt chrome (CoCr) implants in spinal surgery has become increasingly popular. However, there have been no studies specifically comparing biofilm formation on CoCr with that of titanium-alloy spinal implants. The objective of this study was to compare the difference in propensity for biofilm formation between these two materials, as it specifically relates to spinal rods. Staphylococcus aureus subsp. Aureus (ATCC 6538) were incubated with two different types of spinal rods composed of either CoCr or titanium-alloy. The spinal rods were then subject to a trypsin wash to allow for isolation of the colonized organism and associated biofilms. The associated optical density values (OD) from the bacterial isolates were obtained and the bacterial solutions were plated on brain-heart infusion agar plates and the resultant colony-forming units (CFU) were counted. The OD values for the titanium-alloy rods were 1.105±0.096nm (mean±SD) and 1.040±0.026nm at 48hours and 96hours, respectively. In contrast, the OD values for the CoCr rods were 1.332±0.161nm and 1.115±0.207nm at 48 and 96hours, respectively (p<0.05). The CFU values were 1481±417/100mm(2) and 745±159/100mm(2) at 48 and 96hours, respectively for the titanium-alloy group. These values were significantly lower than the CFU values obtained from the CoCr group which were 2721±605/100mm(2) and 928±88/100mm(2) (p<0.001) at both 48 and 96hours respectively. Our findings, evaluating both the OD and CFU values, indicate that implants composed of CoCr had a higher proclivity towards biofilm formation compared to titanium-alloy implants.}, } @article {pmid27396311, year = {2017}, author = {Mazioti, AA and Stasinakis, AS and Psoma, AK and Thomaidis, NS and Andersen, HR}, title = {Hybrid Moving Bed Biofilm Reactor for the biodegradation of benzotriazoles and hydroxy-benzothiazole in wastewater.}, journal = {Journal of hazardous materials}, volume = {323}, number = {Pt A}, pages = {299-310}, doi = {10.1016/j.jhazmat.2016.06.035}, pmid = {27396311}, issn = {1873-3336}, mesh = {Algorithms ; Benzothiazoles/*chemistry ; *Biodegradation, Environmental ; *Biofilms ; Biomass ; *Bioreactors ; Kinetics ; Triazoles/*chemistry ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*chemistry ; }, abstract = {A laboratory scale Hybrid Moving Bed Biofilm Reactor (HMBBR) was used to study the removal of five benzotriazoles and one benzothiazole from municipal wastewater. The HMBBR system consisted of two serially connected fully aerated bioreactors that contained activated sludge (AS) and K3-biocarriers and a settling tank. The average removal of target compounds ranged between 41% (4-methyl-1H-benzotriazole; 4TTR) and 88% (2-hydroxybenzothiazole; OHBTH). Except for 4TTR, degradation mainly occurred in the first bioreactor. Calculation of biodegradation constants in batch experiments and application of a model for describing micropollutants removal in the examined system showed that AS is mainly involved in biodegradation of OHBTH, 1H-benzotriazole (BTR) and xylytriazole (XTR), carriers contribute significantly on 4TTR biodegradation, while both types of biomass participate on elimination of 5-chlorobenzotriazole (CBTR) and 5-methyl-1H-benzotriazole (5TTR). Comparison of the HMBBR system with MBBR or AS systems from literature showed that the HMBBR system was more efficient for the biodegradation of the investigated chemicals. Biotransformation products of target compounds were identified using ultra high-performance liquid chromatography, coupled with a quadrupole-time-of-flight high-resolution mass spectrometer (UHPLC-QToF-MS). Twenty two biotransformation products were tentatively identified, while retention time denoted the formation of more polar transformation products than the parent compounds.}, } @article {pmid27395021, year = {2016}, author = {Del Pozo, JL and Cantón, E}, title = {[Candida biofilm-related infections].}, journal = {Revista iberoamericana de micologia}, volume = {33}, number = {3}, pages = {176-183}, doi = {10.1016/j.riam.2015.06.004}, pmid = {27395021}, issn = {2173-9188}, mesh = {Antifungal Agents/pharmacology/therapeutic use ; *Biofilms ; Candida/drug effects/*physiology ; Candidiasis/drug therapy/*microbiology ; Drug Resistance, Fungal ; *Equipment Contamination ; Humans ; Models, Biological ; }, abstract = {The number of biomedical devices (intravascular catheters, heart valves, joint replacements, etc.) that are implanted in our hospitals has increased exponentially in recent years. Candida species are pathogens which are becoming more significant in these kinds of infections. Candida has two forms of development: planktonic and in biofilms. A biofilm is a community of microorganisms which adhere to a surface and are enclosed by an extracellular matrix. This form of development confers a high resistance to the antimicrobial agents. This is the reason why antibiotic treatments usually fail and biomedical devices may have to be removed in most cases. Unspecific adhesion mechanisms, the adhesion-receptor systems, and an intercellular communication system called quorum sensing play an essential role in the development of Candida biofilms. In general, the azoles have poor activity against Candida biofilms, while echinocandins and polyenes show a greater activity. New therapeutic strategies need to be developed due to the high morbidity and mortality and high economic costs associated with these infections. Most studies to date have focused on bacterial biofilms. The knowledge of the formation of Candida biofilms and their composition is essential to develop new preventive and therapeutic strategies.}, } @article {pmid27394086, year = {2016}, author = {Hyun, HK and Ferracane, JL}, title = {Influence of biofilm formation on the optical properties of novel bioactive glass-containing composites.}, journal = {Dental materials : official publication of the Academy of Dental Materials}, volume = {32}, number = {9}, pages = {1144-1151}, pmid = {27394086}, issn = {1879-0097}, support = {R01 DE021372/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; *Composite Resins ; Dental Materials ; *Glass ; Materials Testing ; *Streptococcus mutans ; Surface Properties ; }, abstract = {OBJECTIVE: Bioactive glass (BAG) has been suggested as a possible additive for dental restorative materials because of its antimicrobial effect and potential for promoting apatite formation in body fluids. The purpose of this study was to investigate the effects of bacterial biofilm on the change of colorimetric value and translucency of novel BAG-containing composites having different initial surface roughness.

METHODS: Composites with 72wt% total filler load were prepared by replacing 15% of the silanized Sr glass with BAG (65 mol % Si; 4% P; 31% Ca), BAG-F (61% Si; 31% Ca; 4% P; 3% F; 1% B), or silanized silica. Light-cured discs of 2-mm thickness (n=10/group) were divided into 4 different surface roughness subgroups produced by wet polishing with 600 and then up to 1200, 2400, or 4000 grit SiC. CIE L*a*b* were measured and the color difference and translucency parameter (TP) were calculated before and after incubating in media with or without a Streptococcus mutans (UA 159) biofilm for 2 wks (no agitation). Results were analyzed using ANOVA/Tukey's test (α=0.05).

RESULTS: All the color differences for BAG and BAG-F composite showed significant decreases with bacterial biofilm compared to media-only. The mean TP (SD) of BAG and BAG-F composite before aging [10.0 (2.8) and 8.5 (1.4)] was higher than that of the control composite [4.9 (0.8)], while the change in TP with aging was greater compared to the control with or without bacteria. BAG-F composites with the smoothest surfaces showed a greater decrease in TP under bacterial biofilm compared to the BAG composite.

SIGNIFICANCE: Highly polished dental composites containing bioactive glass additives may become slightly rougher and show reduced translucency when exposed to bacterial biofilms, but do not discolor any more than control composites that do not contain the BAG.}, } @article {pmid27393887, year = {2016}, author = {Kaushik, S and Sarma, MK and Thungon, PD and Santhosh, M and Goswami, P}, title = {Thin films of silk fibroin and its blend with chitosan strongly promote biofilm growth of Synechococcus sp. BDU 140432.}, journal = {Journal of colloid and interface science}, volume = {479}, number = {}, pages = {251-259}, doi = {10.1016/j.jcis.2016.06.065}, pmid = {27393887}, issn = {1095-7103}, mesh = {Biofilms/*growth & development ; Chitosan/chemistry/*metabolism ; Fibroins/chemistry/isolation & purification/*metabolism ; Silk/chemistry/isolation & purification/*metabolism ; Synechococcus/*growth & development ; }, abstract = {The activating role of different polymer thin films coated over polystyrene support on the Synechococcus sp. biofilm growth was examined concurrently by measuring biofilm florescence using a dye and by measuring cell density in the isolated biofilm. Compared to blank (no coating), the increase in biofilm formation (%) on silk, chitosan, silk-chitosan (3:2) blend, polyaniline, osmium, and Nafion films were 27.73 (31.16), 21.55 (23.74), 37.21 (38.34), 5.35 (8.96), 6.70 (6.55) and (nil), respectively with corresponding cell density (%) shown in the parentheses. This trend of biofilm formation on the films did not significantly vary for Escherichia coli and Lactobacillus plantarum strains. The films of 20 residues long each of glycine-alanine repeat peptide, which mimics a silk fibroin motif, and a hydrophobic glycine-valine repeat peptide, increased the biofilm growth by 13.53 % and 26.08 %, respectively. Silk and blend films showed highest adhesion unit (0.48-0.49), adhesion rate ((4.2-4.8)×10(-6), m/s) and Gibbs energy of adhesion (-8.5 to -8.6kT) with Synechococcus sp. The results confirmed interplay of electrostatic and hydrophobic interaction between cell-surface and polymer films for promoting rapid biofilm growth. This study established that the thin films of silk and the blend (3:2) promote rapid biofilm growth for all the tested microorganisms.}, } @article {pmid27392698, year = {2016}, author = {Chakotiya, AS and Tanwar, A and Narula, A and Sharma, RK}, title = {Alternative to antibiotics against Pseudomonas aeruginosa: Effects of Glycyrrhiza glabra on membrane permeability and inhibition of efflux activity and biofilm formation in Pseudomonas aeruginosa and its in vitro time-kill activity.}, journal = {Microbial pathogenesis}, volume = {98}, number = {}, pages = {98-105}, doi = {10.1016/j.micpath.2016.07.001}, pmid = {27392698}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Biological Transport, Active/drug effects ; Cell Membrane/*drug effects/physiology ; Glycyrrhiza/*chemistry ; Glycyrrhizic Acid/isolation & purification/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Permeability/*drug effects ; Phytochemicals/isolation & purification/pharmacology ; Plant Extracts/isolation & purification/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {The multi-drug resistance offered by Pseudomonas aeruginosa to antibiotics can be attributed towards its propensity to develop biofilm, modification in cell membrane and to efflux antibacterial drugs. The present study explored the activity of Glycyrrhiza glabra and one of its pure compounds, glycyrrhizic acid against P. aeruginosa and their mechanism of action in terms of the effect on membrane permeability, efflux activity, and biofilm formation were determined. Minimum inhibitory concentrations were determined by using broth dilution technique. The minimum bactericidal concentrations were assessed on agar plate. The MIC of the extract and glycyrrhizic acid was found to be 200 and 100 μg ml(-1), respectively. The MBC was found to be 800 and 400 μg ml(-1) in the case of extract and glycyrrhizic acid, respectively. Time -dependent killing efficacy was also estimated. Flowcytometric analysis with staining methods was used to determine the effect of extract and glycyrrhizic acid at 2 × MIC on different physiological parameters and compared it with the standard (antibiotic). The growth of P. aeruginosa was significantly inhibited by extract and the pure compound. The herbal extract and the glycyrrhic acid were also found to effective in targeting the physiological parameters of the bacteria that involve cell membrane permeabilization, efflux activity, and biofilm formation. This study reports the antipseudomonal action of Glycyrrhiza glabra and one of its compound and provides insight into their mode of action.}, } @article {pmid27392247, year = {2016}, author = {Scoffield, J and Silo-Suh, L}, title = {Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {8}, pages = {704-710}, doi = {10.1139/cjm-2016-0119}, pmid = {27392247}, issn = {1480-3275}, mesh = {Biofilms/*growth & development ; Choline/metabolism ; Cystic Fibrosis/complications/*microbiology ; Glycerol/*metabolism ; Humans ; Pseudomonas Infections/complications/*microbiology ; Pseudomonas aeruginosa/genetics/metabolism/*physiology ; Wound Infection/microbiology ; }, abstract = {Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation.}, } @article {pmid27392114, year = {2016}, author = {Sun, Y and Yang, Y and Zhou, D and Cao, Y and Yu, J and Zhao, B and Zhong, M and Li, Y and Yang, J and Yan, H}, title = {Flagellin-rPAc vaccine inhibits biofilm formation but not proliferation of S. mutans.}, journal = {Human vaccines & immunotherapeutics}, volume = {12}, number = {11}, pages = {2847-2854}, pmid = {27392114}, issn = {2164-554X}, mesh = {Administration, Intranasal ; Animals ; Antibodies, Bacterial/*immunology ; Bacterial Proteins/genetics/*immunology ; Biofilms/*growth & development ; Female ; Mice, Inbred BALB C ; Rats, Wistar ; Recombinant Fusion Proteins/genetics/immunology ; Streptococcal Vaccines/administration & dosage/*immunology ; Streptococcus mutans/growth & development/*immunology/*physiology ; Vaccines, Synthetic/administration & dosage/immunology ; }, abstract = {As the main etiologic bacterium of dental caries, Streptococcus mutans (S. mutans) has been considered as the primary object of vaccine research. We previously constructed a recombinant flagellin-rPAc fusion protein (KF-rPAc) that consists of an alanine-rich region to proline-rich region fragment of PAc (rPAc) from S. mutans and flagellin KF from E.coli K12 strain. Intranasal (i.n) immunization of KF-rPAc could induce high level of rPAc-specific antibody responses and offer robust protection against dental caries. In caries development, biofilm formation was considered as the necessary process involved. As PAc possesses other activities besides affecting adherence of S. mutans to salivary glycoproteins, we wondered whether rPAc-specific antibody responses induced by KF-rPAc could inhibit biofilm formation. Hence, in the present study, a simple and convenient in vitro biofilm model of S. mutans was constructed without saliva pre-coated. Both serum and saliva from KF-rPAc immunized rats significantly inhibited biofilm formation. Moreover, with the presence of serum or saliva, the biofilm formation is negatively correlated with the level of rPAc-specific antibody, and positively correlated with caries scores in rat. Moreover, in immunized mice, the level of rPAc-specific antibody also negatively correlated with the biofilm formation. Unlike ampicillin, serum of KF-rPAc immunized mice only inhibited biofilm formation but not proliferation. All together, we discovered that besides the well known blocking adherence of S. mutans to salivary glycoproteins by rPAc-specific antibody, flagellin-rPAc vaccine could also protects tooth from caries by inhibiting biofilm structure formation in between bacteria.}, } @article {pmid27391813, year = {2016}, author = {Grumbein, S and Minev, D and Tallawi, M and Boettcher, K and Prade, F and Pfeiffer, F and Grosse, CU and Lieleg, O}, title = {Hydrophobic Properties of Biofilm-Enriched Hybrid Mortar.}, journal = {Advanced materials (Deerfield Beach, Fla.)}, volume = {28}, number = {37}, pages = {8138-8143}, doi = {10.1002/adma.201602123}, pmid = {27391813}, issn = {1521-4095}, mesh = {Bacteria ; Biofilms ; *Hydrophobic and Hydrophilic Interactions ; Wettability ; }, abstract = {A mortar hybrid material is presented in which biomineralization processes are stimulated by adding a biological component, i.e., bacterial biofilm, to standard mortar. A material is obtained that exhibits increased roughness on the microscale and the nanoscale. Accordingly, the hybrid mortar not only resists wetting but also suppresses the uptake of water by capillary forces.}, } @article {pmid27390886, year = {2016}, author = {Jaffar, N and Miyazaki, T and Maeda, T}, title = {Biofilm formation of periodontal pathogens on hydroxyapatite surfaces: Implications for periodontium damage.}, journal = {Journal of biomedical materials research. Part A}, volume = {104}, number = {11}, pages = {2873-2880}, doi = {10.1002/jbm.a.35827}, pmid = {27390886}, issn = {1552-4965}, mesh = {Aggregatibacter actinomycetemcomitans/*physiology ; Bacteroidaceae Infections/microbiology ; Biofilms/*growth & development ; Dental Enamel/chemistry ; Dentin/chemistry ; Durapatite/*chemistry ; Humans ; Pasteurellaceae Infections/microbiology ; Periodontitis/microbiology ; Periodontium/*microbiology ; Porosity ; Porphyromonas gingivalis/*physiology ; }, abstract = {Biofilm formation of periodontal pathogens on teeth surfaces promotes the progression of periodontal disease. Hence, understanding the mechanisms of bacterial attachment to the dental surfaces may inform strategies for the maintenance of oral health. Although hydroxyapatite (HA) is a major calcium phosphate component of teeth, effect of biofilm formation on HA surfaces remains poorly characterized. In this study, biofilm-forming abilities by the periodontal pathogens Aggregatibacter actinomycetemcomitans Y4 and Porphyromonas gingivalis 381 were investigated on dense and porous HAs that represent enamel and dentin surfaces, respectively. These experiments showed greater biofilm formation on porous HA, but differing attachment profiles and effects of the two pathogens. Specifically, while the detachment of A. actinomycetemcomitans Y4 biofilm was observed, P. gingivalis 381 biofilm increased with time. Moreover, observations of HA morphology following formation of A. actinomycetemcomitans Y4 biofilm revealed gaps between particles, whereas no significant changes were observed in the presence of P. gingivalis 381. Finally, comparisons of calcium leakage showed only slight differences between bacterial species and HA types and may be masked by bacterial calcium uptake. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2873-2880, 2016.}, } @article {pmid27388593, year = {2017}, author = {Castro, FD and Bassin, JP and Dezotti, M}, title = {Treatment of a simulated textile wastewater containing the Reactive Orange 16 azo dye by a combination of ozonation and moving-bed biofilm reactor: evaluating the performance, toxicity, and oxidation by-products.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {7}, pages = {6307-6316}, pmid = {27388593}, issn = {1614-7499}, mesh = {Azo Compounds/*chemistry/isolation & purification/*metabolism/toxicity ; Biodegradation, Environmental ; *Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/microbiology ; Coloring Agents/chemistry/isolation & purification/metabolism/toxicity ; Oxidation-Reduction ; Ozone/*chemistry ; *Textiles ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry ; }, abstract = {In this study, an aqueous solution containing the azo dye Reactive Orange 16 (RO16) was subjected to two sequential treatment processes, namely: ozonation and biological treatment in a moving-bed biofilm reactor (MBBR). The most appropriate ozonation pretreatment conditions for the biological process and the toxicity of the by-products resulting from RO16 ozone oxidation were evaluated. The results showed that more than 97 % of color removal from the dye solutions with RO16 concentrations ranging from 25 to 100 mg/L was observed in 5 min of ozone exposure. However, the maximum total organic carbon removal achieved by ozonation was only 48 %, indicating partial mineralization of the dye. Eleven intermediate organic compounds resulting from ozone treatment of RO16 solution were identified by LC/MS analyses at different contact times. The toxicity of the dye-containing solution decreased after 2 min of ozonation, but increased at longer contact times. The results further demonstrated that the ozonolysis products did not affect the performance of the subsequent MBBR, which achieved an average chemical oxygen demand (COD) and ammonium removal of 93 ± 1 and 97 ± 2 %, respectively. A second MBBR system fed with non-ozonated dye-containing wastewater was run in parallel for comparison purposes. This reactor also showed an appreciable COD (90 ± 1 %) and ammonium removal (97 ± 2 %), but was not effective in removing color, which remained practically invariable over the system. The use of short ozonation times (5 min) and a compact MBBR has shown to be effective for the treatment of the simulated textile wastewater containing the RO16 azo dye.}, } @article {pmid27388200, year = {2016}, author = {Castro, C and Zhang, R and Liu, J and Bellenberg, S and Neu, TR and Donati, E and Sand, W and Vera, M}, title = {Biofilm formation and interspecies interactions in mixed cultures of thermo-acidophilic archaea Acidianus spp. and Sulfolobus metallicus.}, journal = {Research in microbiology}, volume = {167}, number = {7}, pages = {604-612}, doi = {10.1016/j.resmic.2016.06.005}, pmid = {27388200}, issn = {1769-7123}, mesh = {Acidianus/*physiology ; Bacterial Adhesion ; Biofilms/*growth & development ; *Environmental Microbiology ; Iron/metabolism ; *Microbial Interactions ; Microscopy, Confocal ; Sulfides/metabolism ; Sulfolobus/*physiology ; Sulfur/metabolism ; }, abstract = {The understanding of biofilm formation by bioleaching microorganisms is of great importance for influencing mineral dissolution rates and to prevent acid mine drainage (AMD). Thermo-acidophilic archaea such as Acidianus, Sulfolobus and Metallosphaera are of special interest due to their ability to perform leaching at high temperatures, thereby enhancing leaching rates. In this work, leaching experiments and visualization by microscopy of cell attachment and biofilm formation patterns of the crenarchaeotes Sulfolobus metallicus DSM 6482(T) and the Acidianus isolates DSM 29038 and DSM 29099 in pure and mixed cultures on sulfur or pyrite were studied. Confocal laser scanning microscopy (CLSM) combined with fluorescent dyes as well as fluorescently labeled lectins were used to visualize different components (e.g. DNA, proteins or glycoconjugates) of the aforementioned species. The data indicate that cell attachment and the subsequently formed biofilms were species- and substrate-dependent. Pyrite leaching experiments coupled with pre-colonization and further inoculation with a second species suggest that both species may negatively influence each other during pyrite leaching with respect to initial attachment and pyrite dissolution rates. In addition, the investigation of binary biofilms on pyrite showed that both species were heterogeneously distributed on pyrite surfaces in the form of individual cells or microcolonies. Physical contact between the two species seems to occur, as revealed by specific lectins able to specifically bind single species within mixed cultures.}, } @article {pmid27386991, year = {2016}, author = {Zhang, L and Liu, J and Liu, C and Zhang, J and Yang, J}, title = {Performance of a fixed-bed biofilm reactor with microbubble aeration in aerobic wastewater treatment.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {74}, number = {1}, pages = {138-146}, doi = {10.2166/wst.2016.187}, pmid = {27386991}, issn = {0273-1223}, mesh = {Aerobiosis ; Ammonia/chemistry/metabolism ; Bacteria/*metabolism ; Biofilms ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Denitrification ; Microbubbles ; Nitrification ; Oxygen/chemistry/metabolism ; Wastewater/*chemistry ; Water Purification/instrumentation/*methods ; }, abstract = {Microbubble aeration is supposed to be highly efficient for oxygen supply in aerobic wastewater treatment. In the present study, the performance of a fixed-bed biofilm reactor microbubble-aerated using a Shirasu porous glass (SPG) membrane system was investigated when treating synthetic municipal wastewater. The biofilm formation on the carriers was enhanced with microbubble aeration due to the strong adhesion of microbubbles to the solid surface. The dissolved oxygen concentration, the removals of chemical oxygen demand (COD) and nitrogen, and the oxygen utilization efficiency were influenced by the organic loading rate at a certain oxygen supply capacity. The relatively optimal organic loading rate was determined as 0.82 kgCOD/(m(3)d) when the oxygen supply capacity was 0.93 kgO(2)/(m(3)d), where COD and ammonia removal efficiencies were 91.7% and 53.9%, respectively. The corresponding SPG membrane area-based COD removal capacity was 6.88 kgCOD/(m(2)d). The oxygen utilization efficiency of microbubble aeration was obviously higher compared to conventional bubble aeration. The simultaneous nitrification and denitrification occurred in the biofilm reactor and the total nitrogen removal efficiency of 50.4% was achieved under these conditions. In addition, the increase in air supply capacity of the SPG membrane system was suggested to improve its energy utilization efficiency.}, } @article {pmid27386004, year = {2016}, author = {Simões, CA and Conde, NC and Venâncio, GN and Milério, PS and Bandeira, MF and da Veiga Júnior, VF}, title = {Antibacterial Activity of Copaiba Oil Gel on Dental Biofilm.}, journal = {The open dentistry journal}, volume = {10}, number = {}, pages = {188-195}, pmid = {27386004}, issn = {1874-2106}, abstract = {UNLABELLED: Amazonian biodiversity products that have been used for years in folk medicine, have emerged as feasible and promising alternatives for the inhibition of microorganisms in dental biofilm. Copaiba oil, a phytotherapic agent widely used by the Amazonian populations, is known for its antibacterial, anti-inflammatory, anesthetic, healing and antitumor medicinal properties.

OBJECTIVE: The aim of this study was to evaluate the in vitro antibacterial activity of copaiba oil (Copaifera multijuga) gel against strains of Streptococcus sp present in dental biofilm.

MATERIALS AND METHODS: The copaiba oil was obtained and the chemical components were identified. The oil emulsions were formulated and used with the Brain Heart Infusion agar diffusion method with strains of Streptococcus mitis, Streptococcus constellatus and Streptococcus salivarius isolated from patients as well as standard strains of S. mitis (ATCC903), S. mutans (ATCC10449), S. sanguinis (ATCC15300) and S. oralis (ATCC10557). The study groups were as follows: experimental copaiba oil gel, 1% chlorhexidine gel (positive control) and base gel (negative control). The seeded plates were incubated at 37ºC for 12, 24 and 48 hours, respectively. The results obtained were analyzed by Shapiro-Wilk and Friedman Tests (p<0.05) for non parametric data and the Tukey test was used for pH values with 5% level of significance.

RESULTS: The experimental copaiba oil gel and 1% chlorhexidine gel showed antibacterial activity against the tested microorganisms.

CONCLUSION: The copaiba oil gel demonstrated antibacterial activity against all the strains of Streptococcus sp tested, suggesting that it can be used for dental biofilm control.}, } @article {pmid27384343, year = {2016}, author = {Grant, MR and Tymon, LS and Helms, GL and Thomashow, LS and Kent Keller, C and Harsh, JB}, title = {Biofilm adaptation to iron availability in the presence of biotite and consequences for chemical weathering.}, journal = {Geobiology}, volume = {14}, number = {6}, pages = {588-598}, doi = {10.1111/gbi.12187}, pmid = {27384343}, issn = {1472-4669}, mesh = {Aluminum Silicates/*metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Ferrous Compounds/*metabolism ; Iron/*metabolism ; Magnetic Resonance Spectroscopy ; Microscopy, Electron, Scanning ; Pinus/microbiology ; Plant Roots/microbiology ; }, abstract = {Bacteria in nature often live within biofilms, exopolymeric matrices that provide a favorable environment that can differ markedly from their surroundings. Biofilms have been found growing on mineral surfaces and are expected to play a role in weathering those surfaces, but a clear understanding of how environmental factors, such as trace-nutrient limitation, influence this role is lacking. Here, we examine biofilm development by Pseudomonas putida in media either deficient or sufficient in Fe during growth on biotite, an Fe rich mineral, or on glass. We hypothesized that the bacteria would respond to Fe deficiency by enhancing biotite dissolution and by the formation of binding sites to inhibit Fe leaching from the system. Glass coupons acted as a no-Fe control to investigate whether biofilm response depended on the presence of Fe in the supporting solid. Biofilms grown on biotite, as compared to glass, had significantly greater biofilm biomass, specific numbers of viable cells (SNVC), and biofilm cation concentrations of K, Mg, and Fe, and these differences were greater when Fe was deficient in the medium. Scanning electron microscopy (SEM) confirmed that biofilm growth altered the biotite surface, smoothing the rough, jagged edges of channels scratched by hand on the biotite, and dissolving away small, easy-to-access particles scattered across the planar surface. High-resolution magic angle spinning proton nuclear magnetic resonance (HRMAS [1] H NMR) spectroscopy showed that, in the Fe-deficient medium, the relative amount of polysaccharide nearly doubled relative to that in biofilms grown in the medium amended with Fe. The results imply that the bacteria responded to the Fe deficiency by obtaining Fe from biotite and used the biofilm matrix to enhance weathering and as a sink for released cation nutrients. These results demonstrate one mechanism by which biofilms may help soil microbes overcome nutrient deficiencies in oligotrophic systems.}, } @article {pmid27381337, year = {2016}, author = {Jo, SJ and Kwon, H and Jeong, SY and Lee, SH and Oh, HS and Yi, T and Lee, CH and Kim, TG}, title = {Effects of Quorum Quenching on the Microbial Community of Biofilm in an Anoxic/Oxic MBR for Wastewater Treatment.}, journal = {Journal of microbiology and biotechnology}, volume = {26}, number = {9}, pages = {1593-1604}, doi = {10.4014/jmb.1604.04070}, pmid = {27381337}, issn = {1738-8872}, mesh = {*Biofilms ; Biofouling/*prevention & control ; Bioreactors/*microbiology ; *Quorum Sensing ; Wastewater ; Water Purification/instrumentation/*methods ; }, abstract = {Recently, bacterial quorum quenching (QQ) has been proven to have potential as an innovative approach for biofouling control in membrane bioreactors (MBRs) for advanced wastewater treatment. Although information regarding the microbial community is crucial for the development of QQ strategies, little information exists on the microbial ecology in QQ-MBRs. In this study, the microbial communities of biofilm were investigated in relation to the effect of QQ on anoxic/oxic MBRs. Two laboratory-scale MBRs were operated with and without QQ-beads (QQ-bacteria entrapped in beads). The transmembrane pressure increase in the QQ-MBRs was delayed by approximately 100-110% compared with conventional- and vacant-MBRs (beads without QQ-bacteria) at 45 kPa. In terms of the microbial community, QQ gradually favored the development of a diverse and even community. QQ had an effect on both the bacterial composition and change rate of the bacterial composition. Proteobacteria and Bacteroidetes were the most dominant phyla in the biofilm, and the average relative composition of Proteobacteria was low in the QQ-MBR. Thiothrix sp. was the dominant bacterium in the biofilm. The relative composition of Thiothrix sp. was low in the QQ-MBR. These findings provide useful information that can inform the development of a new QQ strategy.}, } @article {pmid27380521, year = {2016}, author = {Ambrosis, N and Boyd, CD and O Toole, GA and Fernández, J and Sisti, F}, title = {Homologs of the LapD-LapG c-di-GMP Effector System Control Biofilm Formation by Bordetella bronchiseptica.}, journal = {PloS one}, volume = {11}, number = {7}, pages = {e0158752}, pmid = {27380521}, issn = {1932-6203}, support = {R01 AI097307/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Blotting, Western ; Bordetella Infections/*microbiology ; Bordetella bronchiseptica/genetics/metabolism/*physiology ; Cyclic GMP/*analogs & derivatives/metabolism ; Female ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Green Fluorescent Proteins/genetics/metabolism ; Host-Pathogen Interactions ; Mice, Inbred BALB C ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Mutation ; Pseudomonas fluorescens/genetics ; Respiratory Tract Infections/microbiology ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction/genetics ; }, abstract = {Biofilm formation is important for infection by many pathogens. Bordetella bronchiseptica causes respiratory tract infections in mammals and forms biofilm structures in nasal epithelium of infected mice. We previously demonstrated that cyclic di-GMP is involved in biofilm formation in B. bronchiseptica. In the present work, based on their previously reported function in Pseudomonas fluorescens, we identified three genes in the B. bronchiseptica genome likely involved in c-di-GMP-dependent biofilm formation: brtA, lapD and lapG. Genetic analysis confirmed a role for BrtA, LapD and LapG in biofilm formation using microtiter plate assays, as well as scanning electron and fluorescent microscopy to analyze the phenotypes of mutants lacking these proteins. In vitro and in vivo studies showed that the protease LapG of B. bronchiseptica cleaves the N-terminal domain of BrtA, as well as the LapA protein of P. fluorescens, indicating functional conservation between these species. Furthermore, while BrtA and LapG appear to have little or no impact on colonization in a mouse model of infection, a B. bronchiseptica strain lacking the LapG protease has a significantly higher rate of inducing a severe disease outcome compared to the wild type. These findings support a role for c-di-GMP acting through BrtA/LapD/LapG to modulate biofilm formation, as well as impact pathogenesis, by B. bronchiseptica.}, } @article {pmid27379078, year = {2016}, author = {Gupta, S and Sharma, AK and Jaiswal, SK and Sharma, VK}, title = {Prediction of Biofilm Inhibiting Peptides: An In silico Approach.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {949}, pmid = {27379078}, issn = {1664-302X}, abstract = {Approximately 75% of microbial infections found in humans are caused by microbial biofilms. These biofilms are resistant to host immune system and most of the currently available antibiotics. Small peptides are extensively studied for their role as anti-microbial peptides, however, only a limited studies have shown their potential as inhibitors of biofilm. Therefore, to develop a unique computational method aimed at the prediction of biofilm inhibiting peptides, the experimentally validated biofilm inhibiting peptides sequences were used to extract sequence based features and to identify unique sequence motifs. Biofilm inhibiting peptides were observed to be abundant in positively charged and aromatic amino acids, and also showed selective abundance of some dipeptides and sequence motifs. These individual sequence based features were utilized to construct Support Vector Machine-based prediction models and additionally by including sequence motifs information, the hybrid models were constructed. Using 10-fold cross validation, the hybrid model displayed the accuracy and Matthews Correlation Coefficient (MCC) of 97.83% and 0.87, respectively. On the validation dataset, the hybrid model showed the accuracy and MCC value of 97.19% and 0.84, respectively. The validated model and other tools developed for the prediction of biofilm inhibiting peptides are available freely as web server at http://metagenomics.iiserb.ac.in/biofin/ and http://metabiosys.iiserb.ac.in/biofin/.}, } @article {pmid27379039, year = {2016}, author = {Li, Y and Jia, R and Al-Mahamedh, HH and Xu, D and Gu, T}, title = {Enhanced Biocide Mitigation of Field Biofilm Consortia by a Mixture of D-Amino Acids.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {896}, pmid = {27379039}, issn = {1664-302X}, abstract = {Microbiologically influenced corrosion (MIC) is a major problem in the oil and gas industry as well as in many other industries. Current treatment methods rely mostly on pigging and biocide dosing. Biocide resistance is a growing concern. Thus, it is desirable to use biocide enhancers to improve the efficacy of existing biocides. D-Amino acids are naturally occurring. Our previous work demonstrated that some D-amino acids are biocide enhancers. Under a biocide stress of 50 ppm (w/w) hydroxymethyl phosphonium sulfate (THPS) biocide, 1 ppm D-tyrosine and 100 ppm D-methionine used separately successfully mitigated the Desulfovibrio vulgaris biofilm on carbon steel coupons. The data reported in this work revealed that 50 ppm of an equimolar mixture of D-methionine, D-tyrosine, D-leucine, and D-tryptophan greatly enhanced 50 ppm THPS biocide treatment of two recalcitrant biofilm consortia containing sulfate reducing bacteria (SRB), nitrate reducing bacteria (NRB), and fermentative bacteria, etc., from oil-field operations. The data also indicated that individual D-amino acids were inadequate for the biofilm consortia.}, } @article {pmid27376835, year = {2016}, author = {Jiang, Y and Tang, B and Xu, Z and Liu, K and Xu, Z and Feng, X and Xu, H}, title = {Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2.}, journal = {Bioresource technology}, volume = {218}, number = {}, pages = {360-366}, doi = {10.1016/j.biortech.2016.06.103}, pmid = {27376835}, issn = {1873-2976}, mesh = {Bacillus subtilis/*metabolism ; Batch Cell Culture Techniques ; *Biofilms ; Bioreactors/*microbiology ; Fermentation ; Glucose ; Glutamic Acid/metabolism ; Polyglutamic Acid/*analogs & derivatives/biosynthesis ; }, abstract = {The production of poly-γ-glutamic acid (γ-PGA) by Bacillus subtilis NX-2 using a moving bed biofilm reactor (MBBR) system was tested for the first time in this study. Polypropylene TL-2 was chosen as a suitable carrier, and γ-PGA concentration of 42.7±0.86g/L and productivity of 0.59±0.06g/(Lh) were obtained in batch fermentation. After application of the strategy of dissolved oxygen (DO)-stat feeding, higher γ-PGA concentration and productivity were achieved than with glucose feedback feeding. Finally, the repeated fed-batch cultures implemented in the MBBR system showed high stability, and the maximal γ-PGA concentration and productivity of 74.2g/L and 1.24g/(Lh) were achieved, respectively. In addition, the promotion of oxygen transfer by an MBBR carrier was well explained by a computational fluid dynamics (CFD) simulation. These results suggest that an MBBR system could be applied to large-scale γ-PGA production.}, } @article {pmid27376326, year = {2016}, author = {Oyama, T and Miyazaki, M and Yoshimura, M and Takata, T and Ohjimi, H and Jimi, S}, title = {Biofilm-Forming Methicillin-Resistant Staphylococcus aureus Survive in Kupffer Cells and Exhibit High Virulence in Mice.}, journal = {Toxins}, volume = {8}, number = {7}, pages = {}, pmid = {27376326}, issn = {2072-6651}, mesh = {Animals ; Bacterial Load ; Biofilms/*growth & development ; Female ; Kupffer Cells/*microbiology ; Methicillin-Resistant Staphylococcus aureus/*growth & development/metabolism/*pathogenicity ; Mice, Inbred C57BL ; Microbial Viability ; Polysaccharides, Bacterial/metabolism ; Staphylococcal Infections/blood/*microbiology ; Time Factors ; Virulence ; }, abstract = {Although Staphylococcus aureus is part of the normal body flora, heavy usage of antibiotics has resulted in the emergence of methicillin-resistant strains (MRSA). MRSA can form biofilms and cause indwelling foreign body infections, bacteremia, soft tissue infections, endocarditis, and osteomyelitis. Using an in vitro assay, we screened 173 clinical blood isolates of MRSA and selected 20 high-biofilm formers (H-BF) and low-biofilm formers (L-BF). These were intravenously administered to mice and the general condition of mice, the distribution of bacteria, and biofilm in the liver, lung, spleen, and kidney were investigated. MRSA count was the highest in the liver, especially within Kupffer cells, which were positive for acid polysaccharides that are associated with intracellular biofilm. After 24 h, the general condition of the mice worsened significantly in the H-BF group. In the liver, bacterial deposition and aggregation and the biofilm-forming spot number were all significantly greater for H-BF group than for L-BF. CFU analysis revealed that bacteria in the H-BF group survived for long periods in the liver. These results indicate that the biofilm-forming ability of MRSA is a crucial factor for intracellular persistence, which could lead to chronic infections.}, } @article {pmid27376044, year = {2016}, author = {Roudbarmohammadi, S and Roudbary, M and Bakhshi, B and Katiraee, F and Mohammadi, R and Falahati, M}, title = {ALS1 and ALS3 gene expression and biofilm formation in Candida albicans isolated from vulvovaginal candidiasis.}, journal = {Advanced biomedical research}, volume = {5}, number = {}, pages = {105}, pmid = {27376044}, issn = {2277-9175}, abstract = {BACKGROUND: A cluster of genes are involved in the pathogenesis and adhesion of Candida albicans to mucosa and epithelial cells in the vagina, the important of which is agglutinin-like sequence (ALS) genes. As well as vaginitis is a significant health problem among women, the antifungal resistance of Candida species is continually increasing. This cross-sectional study investigates the expression of ALS1 and ALS3 genes and biofilm formation in C. albicans isolate isolated from vaginitis.

MATERIALS AND METHODS: Fifty-three recognized isolates of C. albicans were collected from women with recurrent vulvovaginal candidiasis in Iran, cultured on sabouraud dextrose agar, and then examined for gene expression. Total messenger RNA (mRNA) extracted from C. albicans isolates and complementary DNA synthesized using reverse transcriptase enzyme. Reverse transcription-polymerase chain reaction (RT-PCR) using specific primer was used to evaluate the expression of ALS1 and ALS3 through housekeeping (ACT1) genes. 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide assay was performed to assess adherence capacity and biofilm formation in the isolated.

RESULTS: Forty isolates (75.8%) expressed ALS1 and 41 isolates (77.7%) expressed ALS3 gene. Moreover, 39 isolates (74%) were positive for both ALS1 and ALS3 mRNA by the RT-PCR. Adherence capability in isolates with ALS1 or ALS3 genes expression was greater than the control group (with any gene expression), besides, it was significantly for the most in the isolates that expressed both ALS1 and ALS3 genes simultaneously.

CONCLUSION: The results attained indicated that there is an association between the expression of ALS1 and ALS3 genes and fluconazole resistance in C. albicans. A considerable percent of the isolates expressing the ALS1 and ALS3 genes may have contributed to their adherence to vagina and biofilm formation.}, } @article {pmid27375612, year = {2016}, author = {Sherry, L and Lappin, G and O'Donnell, LE and Millhouse, E and Millington, OR and Bradshaw, DJ and Axe, AS and Williams, C and Nile, CJ and Ramage, G}, title = {Viable Compositional Analysis of an Eleven Species Oral Polymicrobial Biofilm.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {912}, pmid = {27375612}, issn = {1664-302X}, abstract = {PURPOSE: Polymicrobial biofilms are abundant in clinical disease, particularly within the oral cavity. Creating complex biofilm models that recapitulate the polymicrobiality of oral disease are important in the development of new chemotherapeutic agents. In order to do this accurately we require the ability to undertake compositional analysis, in addition to determine individual cell viability, which is difficult using conventional microbiology. The aim of this study was to develop a defined multispecies denture biofilm model in vitro, and to assess viable compositional analysis following defined oral hygiene regimens.

METHODS: An in vitro multispecies denture biofilm containing various oral commensal and pathogenic bacteria and yeast was created on poly (methyl methacrylate) (PMMA). Denture hygiene regimens tested against the biofilm model included brushing only, denture cleansing only and combinational brushing and denture cleansing. Biofilm composition and viability were assessed by culture (CFU) and molecular (qPCR) methodologies. Scanning electron microscopy and confocal laser scanning microscopy were also employed to visualize changes in denture biofilms following treatment.

RESULTS: Combinational treatment of brushing and denture cleansing had the greatest impact on multispecies denture biofilms, reducing the number of live cells by more than 2 logs, and altering the overall composition in favor of streptococci. This was even more evident during the sequential testing, whereby daily sequential treatment reduced the total and live number of bacteria and yeast more than those treated intermittently. Bacteria and yeast remaining following treatment tended to aggregate in the pores of the PMMA, proving more difficult to fully eradicate the biofilm.

CONCLUSIONS: Overall, we are the first to develop a method to enable viable compositional analysis of an 11 species denture biofilm following chemotherapeutic challenge. We were able to demonstrate viable cell reduction and changes in population dynamics following evaluation of various denture cleansing regimens. Specifically, it was demonstrated that daily combinational treatment of brushing and cleansing proved to be the most advantageous denture hygiene regimen, however, residual organisms still remained within the pores of PMMA surface, which could act as a reservoir for further biofilm regrowth. We have identified an industry need for denture cleansing agents with the capacity to penetrate these pores and disaggregate these complex biofilm consortia.}, } @article {pmid27375583, year = {2016}, author = {Kaur, G and Balamurugan, P and Uma Maheswari, C and Anitha, A and Princy, SA}, title = {Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {861}, pmid = {27375583}, issn = {1664-302X}, abstract = {Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25-62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.}, } @article {pmid27375578, year = {2016}, author = {Fagerlund, A and Langsrud, S and Heir, E and Mikkelsen, MI and Møretrø, T}, title = {Biofilm Matrix Composition Affects the Susceptibility of Food Associated Staphylococci to Cleaning and Disinfection Agents.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {856}, pmid = {27375578}, issn = {1664-302X}, abstract = {Staphylococci are frequently isolated from food processing environments, and it has been speculated whether survival after cleaning and disinfection with benzalkonium chloride (BC)-containing disinfectants is due to biofilm formation, matrix composition, or BC efflux mechanisms. Out of 35 food associated staphylococci, eight produced biofilm in a microtiter plate assay and were identified as Staphylococcus capitis (2), S. cohnii, S. epidermidis, S. lentus (2), and S. saprophyticus (2). The eight biofilm producing strains were characterized using whole genome sequencing. Three of these strains contained the ica operon responsible for production of a polysaccharide matrix, and formed a biofilm which was detached upon exposure to the polysaccharide degrading enzyme Dispersin B, but not Proteinase K or trypsin. These strains were more tolerant to the lethal effect of BC both in suspension and biofilm than the remaining five biofilm producing strains. The five BC susceptible strains were characterized by lack of the ica operon, and their biofilms were detached by Proteinase K or trypsin, but not Dispersin B, indicating that proteins were major structural components of their biofilm matrix. Several novel cell wall anchored repeat domain proteins with domain structures similar to that of MSCRAMM adhesins were identified in the genomes of these strains, potentially representing novel mechanisms of ica-independent biofilm accumulation. Biofilms from all strains showed similar levels of detachment after exposure to alkaline chlorine, which is used for cleaning in the food industry. Strains with qac genes encoding BC efflux pumps could grow at higher concentrations of BC than strains without these genes, but no differences were observed at biocidal concentrations. In conclusion, the biofilm matrix of food associated staphylococci varies with respect to protein or polysaccharide nature, and this may affect the sensitivity toward a commonly used disinfectant.}, } @article {pmid27375568, year = {2016}, author = {Hayrapetyan, H and Siezen, R and Abee, T and Nierop Groot, M}, title = {Comparative Genomics of Iron-Transporting Systems in Bacillus cereus Strains and Impact of Iron Sources on Growth and Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {842}, pmid = {27375568}, issn = {1664-302X}, abstract = {Iron is an important element for bacterial viability, however it is not readily available in most environments. We studied the ability of 20 undomesticated food isolates of Bacillus cereus and two reference strains for capacity to use different (complex) iron sources for growth and biofilm formation. Studies were performed in media containing the iron scavenger 2,2-Bipyridine. Transcriptome analysis using B. cereus ATCC 10987 indeed showed upregulation of predicted iron transporters in the presence of 2,2-Bipyridine, confirming that iron was depleted upon its addition. Next, the impact of iron sources on growth performance of the 22 strains was assessed and correlations between growth stimulation and presence of putative iron transporter systems in the genome sequences were analyzed. All 22 strains effectively used Fe citrate and FeCl3 for growth, and possessed genes for biosynthesis of the siderophore bacillibactin, whereas seven strains lacked genes for synthesis of petrobactin. Hemoglobin could be used by all strains with the exception of one strain that lacked functional petrobactin and IlsA systems. Hemin could be used by the majority of the tested strains (19 of 22). Notably, transferrin, ferritin, and lactoferrin were not commonly used by B. cereus for growth, as these iron sources could be used by 6, 3, and 2 strains, respectively. Furthermore, biofilm formation was found to be affected by the type of iron source used, including stimulation of biofilms at liquid-air interphase (FeCl3 and Fe citrate) and formation of submerged type biofilms (hemin and lactoferrin). Our results show strain variability in the genome-encoded repertoire of iron-transporting systems and differences in efficacy to use complex iron sources for growth and biofilm formation. These features may affect B. cereus survival and persistence in specific niches.}, } @article {pmid27375563, year = {2016}, author = {Ren, GX and Fan, S and Guo, XP and Chen, S and Sun, YC}, title = {Differential Regulation of c-di-GMP Metabolic Enzymes by Environmental Signals Modulates Biofilm Formation in Yersinia pestis.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {821}, pmid = {27375563}, issn = {1664-302X}, abstract = {Cyclic diguanylate (c-di-GMP) is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs), HmsT and HmsD and one phosphodiesterase (PDE), HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD, and HmsP in Y. pestis. Biofilm formation was higher in the presence of non-lethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulate activity of DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.}, } @article {pmid27375253, year = {2016}, author = {García-Heredia, A and García, S and Merino-Mascorro, JÁ and Feng, P and Heredia, N}, title = {Natural plant products inhibits growth and alters the swarming motility, biofilm formation, and expression of virulence genes in enteroaggregative and enterohemorrhagic Escherichia coli.}, journal = {Food microbiology}, volume = {59}, number = {}, pages = {124-132}, doi = {10.1016/j.fm.2016.06.001}, pmid = {27375253}, issn = {1095-9998}, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects/growth & development ; Enterohemorrhagic Escherichia coli/*drug effects/genetics/pathogenicity/*physiology ; Escherichia coli O157/*drug effects/genetics/pathogenicity/physiology ; Escherichia coli Proteins/genetics ; Gene Expression ; Genotype ; Microbial Sensitivity Tests ; Origanum ; Phenotype ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Real-Time Polymerase Chain Reaction ; Rifamycins/pharmacology ; Rifaximin ; Serine Endopeptidases/genetics ; Shiga Toxin 2/genetics ; Shiga-Toxigenic Escherichia coli/*drug effects/growth & development/pathogenicity/physiology ; Sigma Factor/genetics ; Virulence/drug effects/genetics ; }, abstract = {The purpose of this study was to determine the effects of plant products on the growth, swarming motility, biofilm formation and virulence gene expression in enterohemorrhagic Escherichia coli O157:H7 and enteroaggregative E. coli strain 042 and a strain of O104:H4 serotype. Extracts of Lippia graveolens and Haematoxylon brassiletto, and carvacrol, brazilin were tested by an antimicrobial microdilution method using citral and rifaximin as controls. All products showed bactericidal activity with minimal bactericidal concentrations ranging from 0.08 to 8.1 mg/ml. Swarming motility was determined in soft LB agar. Most compounds reduced swarming motility by 7%-100%; except carvacrol which promoted motility in two strains. Biofilm formation studies were done in microtiter plates. Rifaximin inhibited growth and reduced biofilm formation, but various concentrations of other compounds actually induced biofilm formation. Real time PCR showed that most compounds decreased stx2 expression. The expression of pic and rpoS in E. coli 042 were suppressed but in E. coli O104:H4 they varied depending on compounds. In conclusion, these extracts affect E. coli growth, swarming motility and virulence gene expression. Although these compounds were bactericidal for pathogenic E. coli, sublethal concentrations had varied effects on phenotypic and genotypic traits, and some increased virulence gene expression.}, } @article {pmid27374894, year = {2016}, author = {Rahimi, F and Katouli, M and Karimi, S}, title = {Biofilm production among methicillin resistant Staphylococcus aureus strains isolated from catheterized patients with urinary tract infection.}, journal = {Microbial pathogenesis}, volume = {98}, number = {}, pages = {69-76}, doi = {10.1016/j.micpath.2016.06.031}, pmid = {27374894}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/analysis/genetics ; Biofilms/*growth & development ; Genetic Variation ; Genotype ; Humans ; Iran ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus/classification/genetics/*isolation & purification/*physiology ; Molecular Typing ; Oxacillin/pharmacology ; Penicillin-Binding Proteins/analysis/genetics ; Staphylococcal Infections/*microbiology ; Urinary Tract Infections/*microbiology ; }, abstract = {Between June 2011 and May 2014, we isolated a total of 419 Staphylococcus aureus strains from catheterized patients with UTI in a referral hospital in Tehran. Of these, 108 were identified as methicillin resistant (MRSA) based on their phenotypic resistance to oxacillin and the presence of mecA gene. The MRSA isolates were tested for their clonality using a combination of PFGE, prophage typing, SCCmec and ccr typing and examined for their biofilm formation as well as their resistance against 17 antibiotics. In all, 15 common pulsotypes consisted of 105 isolates and 3 single types were identified among the MRSA strains of which, 97% carried SCCmec type III and type 3 ccr. Eighty three (77%) strains were positive for biofilm formation and also carried icaA and icaD genes. Moreover, agr group III and its related tst gene were detected in 81% and 77% of biofilm producing strains, respectively 105 of the 108 MRSA were multidrug resistant with 82.4% being resistant to more than 10 antibiotics. Strains with SCCmec type IV and type 2 ccr, contained SGA and SGL prophage types, were positive for pvl gene and belonged to single PFGE types. This study highlights the important role of biofilm formation and virulence factors of MRSA strains in catheterized patients.}, } @article {pmid27374070, year = {2016}, author = {Su, Y and Mennerich, A and Urban, B}, title = {The long-term effects of wall attached microalgal biofilm on algae-based wastewater treatment.}, journal = {Bioresource technology}, volume = {218}, number = {}, pages = {1249-1252}, doi = {10.1016/j.biortech.2016.06.099}, pmid = {27374070}, issn = {1873-2976}, mesh = {Biofilms/*growth & development ; Microalgae/*growth & development ; Nitrogen ; Phosphorus ; Photobioreactors/*microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/*microbiology ; }, abstract = {The influence of the reactor wall attached biofilm on the nutrient removal performance was investigated in an open photobioreactor during long-term operation. Total nitrogen and phosphorus removal efficiencies were statistically similar between reactor with (reactor A) and without (reactor B) biofilm at the Hydraulic Retention Time (HRT) of 18, 13.5 and 9days. When the HRT reduced to 8days, total nitrogen and phosphorus removal efficiencies in the reactor A were 42.95±5.11% and 97.97±1.12%, respectively, while significant lower removal efficiencies (38.06±5.80% for total nitrogen and 83.14±8.16% for phosphorus) were obtained in the reactor B. The VSS concentrations throughout the test were statistically similar for the two reactors, with a mean value of 0.63±0.25g/l for reactor A and 0.69±0.20g/l for reactor B. This study indicated that the reactor wall attached biofilm supported high phosphorus and nitrogen removal, which may provide insight into the practical implementation of microalgae-based wastewater treatment.}, } @article {pmid27373086, year = {2016}, author = {Di, R and Dong, D and Ye, L and Zhao, Y}, title = {[Staphylococcus aureus biofilm influences the expression of lysozyme, SLPI and gp340 in a human sinonasal explant model].}, journal = {Lin chuang er bi yan hou tou jing wai ke za zhi = Journal of clinical otorhinolaryngology, head, and neck surgery}, volume = {30}, number = {3}, pages = {194-199}, pmid = {27373086}, issn = {2096-7993}, mesh = {*Biofilms ; Calcium-Binding Proteins ; DNA-Binding Proteins ; Enzyme-Linked Immunosorbent Assay ; Ethmoid Sinus/*metabolism/*microbiology ; Humans ; Immunity, Innate ; Muramidase/*metabolism ; RNA, Messenger/metabolism ; Receptors, Cell Surface/*metabolism ; Secretory Leukocyte Peptidase Inhibitor/*metabolism ; Staphylococcal Infections/metabolism ; Tissue Culture Techniques ; Tumor Suppressor Proteins ; }, abstract = {OBJECTIVE: To investigate the influences of staphylococcus aureus in planktonic and biofilm forms on the expression of lysozyme, SLPI and gp340 in the human sinonasal explant model.

METHOD: Mucosa samples from ethmoid sinus were collected from ten patients of cerebrospinal fluid leak and were cultured with and without S. aureus biofilms and planktonic cells. After the infection, the explant model was confirmed by CLSM, and the secretion of lysozyme, SLPI and gp340 was detected by enzyme-linked immunosorbent assay (ELISA) at 8, 16, and 24 h after S. aureus challenge. Expressions of lysozyme, SLPI and gp340 in mRNA and protein levels after 24 h S. aureus challenge were detected using RT-PCR, immunohistochemistry and Western bolt assay respectively.

RESULT: The secretion of lysozyme, SLPI and gp340 in the explant model was observed with a trend to increase in a time-dependent manner. At 8 and 16 h after S. aureus challenge, the secretion of lysozyme, SLPI and gp340 in biofilms group was significantly higher than these in planktonic cells group and control group (P<0. 05). S. aureus biofilms enhanced the mRNA expressions of lysozyme, SLPI and gp340 significantly compared with planktonic cells and controls, and the mRNA expressions in the explant model challenged by planktonic cells were significantly higher than controls (P < 0.05). Although the Western bolt assay showed no differences between the lysozyme expression in the planktonic cells group and control group (P > 0.05), the biofilms enhanced the expressions of lysozyme, SLPI and gp340 significantly compared with planktonic cells and controls (P < 0.05).

CONCLUSION: S. aureus biofilm induced the expressions of lysozyme, SLPI and gp340 to a higher level than planktonic cells, indicating that S. aureus biofilm was an influencing factor on the innate immune system.}, } @article {pmid27373066, year = {2016}, author = {Wu, Q and Zhong, X and Zhang, J}, title = {[Research progress in biofilm formation and regulatory mechanism of Campylobacter jejuni].}, journal = {Wei sheng wu xue bao = Acta microbiologica Sinica}, volume = {56}, number = {2}, pages = {180-187}, pmid = {27373066}, issn = {0001-6209}, mesh = {Bacterial Adhesion/drug effects ; *Biofilms ; Campylobacter jejuni/*drug effects/genetics/*physiology ; Disinfectants/*pharmacology ; }, abstract = {Biofilm of Campylobacter jejuni was formed by cross-linking its extracellular secretion, polysaccharides, various extracellular proteins, nucleic acids etc to enhance its survival in hostile environments, especially for detergents, antibiotics and disinfectants. This paper elaborated C. jejuni biofilm formation and regulation mechanisms in the surface properties of the media, temperatures, gas environment, the regulation of gene etc, also analysed and discussed a variety of biofilm removal practical applications. We hope it can provide a reference for studies on biofilm control of C. jejuni.}, } @article {pmid27369898, year = {2016}, author = {Maldarelli, GA and Piepenbrink, KH and Scott, AJ and Freiberg, JA and Song, Y and Achermann, Y and Ernst, RK and Shirtliff, ME and Sundberg, EJ and Donnenberg, MS and von Rosenvinge, EC}, title = {Type IV pili promote early biofilm formation by Clostridium difficile.}, journal = {Pathogens and disease}, volume = {74}, number = {6}, pages = {}, pmid = {27369898}, issn = {2049-632X}, support = {F30 DK105539/DK/NIDDK NIH HHS/United States ; T32 AI007540/AI/NIAID NIH HHS/United States ; F32 AI110045/AI/NIAID NIH HHS/United States ; R01 AI114902/AI/NIAID NIH HHS/United States ; R21 AI105881/AI/NIAID NIH HHS/United States ; T32 AI095190/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; Clostridioides difficile/*physiology ; Cluster Analysis ; Enterocolitis, Pseudomembranous/*microbiology ; Fimbriae Proteins/genetics ; Fimbriae, Bacterial/*physiology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; High-Throughput Nucleotide Sequencing ; Humans ; Mutation ; Phenotype ; Transcriptome ; }, abstract = {Increasing morbidity and mortality from Clostridium difficile infection (CDI) present an enormous challenge to healthcare systems. Clostridium difficile express type IV pili (T4P), but their function remains unclear. Many chronic and recurrent bacterial infections result from biofilms, surface-associated bacterial communities embedded in an extracellular matrix. CDI may be biofilm mediated; T4P are important for biofilm formation in a number of organisms. We evaluate the role of T4P in C. difficile biofilm formation using RNA sequencing, mutagenesis and complementation of the gene encoding the major pilin pilA1, and microscopy. RNA sequencing demonstrates that, in comparison to other growth phenotypes, C. difficile growing in a biofilm has a distinct RNA expression profile, with significant differences in T4P gene expression. Microscopy of T4P-expressing and T4P-deficient strains suggests that T4P play an important role in early biofilm formation. A non-piliated pilA1 mutant forms an initial biofilm of significantly reduced mass and thickness in comparison to the wild type. Complementation of the pilA1 mutant strain leads to formation of a biofilm which resembles the wild-type biofilm. These findings suggest that T4P play an important role in early biofilm formation. Novel strategies for confronting biofilm infections are emerging; our data suggest that similar strategies should be investigated in CDI.}, } @article {pmid27369177, year = {2016}, author = {Marshall, JS}, title = {A model of ultrasound-enhanced diffusion in a biofilm.}, journal = {The Journal of the Acoustical Society of America}, volume = {139}, number = {6}, pages = {EL228}, doi = {10.1121/1.4954635}, pmid = {27369177}, issn = {1520-8524}, mesh = {Bacteria/growth & development/metabolism/*radiation effects ; Biofilms/growth & development/*radiation effects ; Diffusion ; *Models, Biological ; Motion ; Nanoparticles/*chemistry/metabolism ; Porosity ; Stochastic Processes ; Time Factors ; *Ultrasonic Waves ; Ultrasonics/*methods ; }, abstract = {A stochastic model is presented for nanoparticle transport in a biofilm to explain how the combination of acoustic oscillations and intermittent retention due to interaction with the pore walls of the biofilm leads to diffusion enhancement. An expression for the effective diffusion coefficient was derived that varies with the square of the oscillation velocity amplitude. This expression was validated by comparison of an analytical diffusion solution to the stochastic model prediction. The stochastic model was applied to an example problem associated with liposome penetration into a hydrogel, and it was found to yield solutions in which liposome concentration varied exponentially with distance into the biofilm.}, } @article {pmid27368765, year = {2016}, author = {Cavalcanti, YW and Wilson, M and Lewis, M and Williams, D and Senna, PM and Del-Bel-Cury, AA and da Silva, WJ}, title = {Corrigendum to "Salivary pellicles equalise surfaces' charges and modulate the virulence of Candida albicans biofilm" [Arch. Oral Biol. 66 (2016) 129-140].}, journal = {Archives of oral biology}, volume = {69}, number = {}, pages = {109}, doi = {10.1016/j.archoralbio.2016.06.017}, pmid = {27368765}, issn = {1879-1506}, } @article {pmid27367683, year = {2016}, author = {Zhang, K and Ren, B and Zhou, X and Xu, HH and Chen, Y and Han, Q and Li, B and Weir, MD and Li, M and Feng, M and Cheng, L}, title = {Effect of Antimicrobial Denture Base Resin on Multi-Species Biofilm Formation.}, journal = {International journal of molecular sciences}, volume = {17}, number = {7}, pages = {}, pmid = {27367683}, issn = {1422-0067}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {Anti-Infective Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Candida albicans/drug effects ; Dental Materials/chemistry/*pharmacology ; Denture Bases/*microbiology ; Real-Time Polymerase Chain Reaction ; Resins, Plant/pharmacology ; Streptococcus mutans/drug effects ; Streptococcus sanguis/drug effects ; }, abstract = {Our aims of the research were to study the antimicrobial effect of dimethylaminododecyl methacrylate (DMADDM) modified denture base resin on multi-species biofilms and the biocompatibility of this modified dental material. Candida albicans (C. albicans), Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), as well as Actinomyces naeslundii (A. naeslundii) were used for biofilm formation on denture base resin. Colony forming unit (CFU) counts, microbial viability staining, and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) array were used to evaluate the antimicrobial effect of DMADDM. C. albicans staining and Real-time PCR were used to analyze the morphology and expression of virulence genes of C. albicans in biofilm. Lactate dehydrogenase (LDH) array and Real-time PCR were conducted to examine the results after biofilm co-cultured with epithelial cell. Hematoxylin and eosin (HE) staining followed by histological evaluation were used to study the biocompatibility of this modified material. We found that DMADDM containing groups reduced both biomass and metabolic activity of the biofilm significantly. DMADDM can also inhibit the virulence of C. albicans by means of inhibiting the hyphal development and downregulation of two virulence related genes. DMADDM significantly reduced the cell damage caused by multi-species biofilm according to the LDH activity and reduced the expression of IL-18 gene of the cells simultaneously. The in vivo histological evaluation proved that the addition of DMADDM less than 6.6% in denture material did not increase the inflammatory response (p > 0.05). Therefore, we proposed that the novel denture base resin containing DMADDM may be considered as a new promising therapeutic system against problems caused by microbes on denture base such as denture stomatitis.}, } @article {pmid27367677, year = {2016}, author = {Yang, X and Sha, K and Xu, G and Tian, H and Wang, X and Chen, S and Wang, Y and Li, J and Chen, J and Huang, N}, title = {Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.}, journal = {International journal of molecular sciences}, volume = {17}, number = {7}, pages = {}, pmid = {27367677}, issn = {1422-0067}, mesh = {Adhesins, Escherichia coli/genetics/metabolism ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Disulfides ; Escherichia coli Proteins/genetics/metabolism ; Gene Expression Regulation, Bacterial/drug effects/genetics ; Sulfinic Acids/*pharmacology ; Uropathogenic Escherichia coli/*drug effects/growth & development/metabolism/*physiology ; }, abstract = {Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.}, } @article {pmid27366751, year = {2016}, author = {Chai, D and Liu, X and Wang, R and Bai, Y and Cai, Y}, title = {Efficacy of Linezolid and Fosfomycin in Catheter-Related Biofilm Infection Caused by Methicillin-Resistant Staphylococcus aureus.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {6413982}, pmid = {27366751}, issn = {2314-6141}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage ; Biofilms/*drug effects ; Catheter-Related Infections/*drug therapy ; Catheterization ; Drug Combinations ; Drug Interactions ; Fosfomycin/*administration & dosage ; Linezolid/*administration & dosage ; Male ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Microbial Sensitivity Tests ; Rats ; Rats, Wistar ; Staphylococcal Infections/*drug therapy ; }, abstract = {As long-standing clinical problems, catheter-related infections and other chronic biofilm infections are more difficult to treat due to the high antibiotic resistance of biofilm. Therefore, new treatments are needed for more effective bacteria clearance. In this study, we evaluated the antibacterial activities of several common antibiotics alone and their combinations against biofilm-embedded methicillin-resistant staphylococcus aureus (MRSA) infections, both in vitro and in vivo. In brief, fosfomycin, levofloxacin, and rifampin alone or in combination with linezolid were tested in vitro against planktonic and biofilm-embedded MRSA infection in three MRSA stains. The synergistic effects between linezolid and the other three antibiotics were assessed by fractional inhibitory concentration index (FICI) and time-kill curves, where the combination of linezolid plus fosfomycin showed the best synergistic effect in all strains. For further evaluation in vivo, we applied the combination of linezolid and fosfomycin in a catheter-related biofilm rat model and found that viable bacteria counts in biofilm were significantly reduced after treatment (P < 0.05). In summary, we have shown here that the combination of linezolid and fosfomycin treatment had improved therapeutic effects on biofilm-embedded MRSA infection both in vitro and in vivo, which provided important basis for new clinical therapy development.}, } @article {pmid27362920, year = {2016}, author = {He, X and Wang, J and Abdoli, L and Li, H}, title = {Mg(2+)/Ca(2+) promotes the adhesion of marine bacteria and algae and enhances following biofilm formation in artificial seawater.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {146}, number = {}, pages = {289-295}, doi = {10.1016/j.colsurfb.2016.06.029}, pmid = {27362920}, issn = {1873-4367}, mesh = {Bacterial Adhesion/*drug effects ; Bacterial Proteins/biosynthesis ; Biofilms/*growth & development ; Calcium/*pharmacology ; Chlorella/drug effects/*physiology ; Diatoms/drug effects/*physiology ; Magnesium/*pharmacology ; Polymers/*chemistry/metabolism ; Polysaccharides/chemical synthesis ; Seawater/*chemistry ; }, abstract = {Adhesion of microorganisms in the marine environment is essential for initiation and following development of biofouling. A variety of factors play roles in regulating the adhesion. Here we report the influence of Ca(2+) and Mg(2+) in artificial seawater on attachment and colonization of Bacillus sp., Chlorella and Phaeodactylum tricornutum on silicon wafer. Extra addition of the typical divalent cations in culturing solution gives rise to significantly enhanced adhesion of the microorganisms. Mg(2+) and Ca(2+) affect the adhesion of Bacillus sp. presumably by regulating aggregation and formation of extracellular polymeric substances (EPS). The ions alter quantity and types of the proteins in EPS, in turn affecting subsequent adhesion. However, it is noted that Mg(2+) promotes adhesion of Chlorella likely by regulating EPS formation and polysaccharide synthesis. Ca(2+) plays an important role in protein expression to enhance the adhesion of Chlorella. For Phaeodactylum tricornutum, Ca(2+) expedites protein synthesis for enhanced adhesion. The results shed some light on effective ways of utilizing divalent cations to mediate formation of biofilms on the marine structures for desired performances.}, } @article {pmid27357319, year = {2016}, author = {Wang, SP and Ge, Y and Zhou, XD and Xu, HH and Weir, MD and Zhang, KK and Wang, HH and Hannig, M and Rupf, S and Li, Q and Cheng, L}, title = {Effect of anti-biofilm glass-ionomer cement on Streptococcus mutans biofilms.}, journal = {International journal of oral science}, volume = {8}, number = {2}, pages = {76-83}, pmid = {27357319}, issn = {2049-3169}, support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {*Anti-Bacterial Agents ; *Biofilms ; *Glass Ionomer Cements ; Humans ; Lactic Acid ; *Streptococcus mutans ; }, abstract = {Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial glass-ionomer cements (GIC) containing a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and to investigate their effect on material performance and antibacterial properties. Different mass fractions (0, 1.1% and 2.2%) of DMADDM were incorporated into the GIC. The flexure strength, surface charge density, surface roughness and fluoride release were tested. A Streptococcus mutans biofilm model was used. Exopolysaccharides (EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm matrix. In addition, biofilm metabolic activity, lactic acid metabolism and the expression of glucosyltransferase genes gtfB, gtfC and gtfD were measured. GIC containing 1.1% and 2.2% DMADDM had flexural strengths matching those of the commercial control (P>0.1). DMADDM was able to increase the surface charge density but reduced surface roughness (P<0.05). The incorporation of 1.1% and 2.2% DMADDM elevated the release of fluoride by the GIC in the first 2 days (P<0.05). The novel DMADDM-modified GIC significantly reduced biofilm metabolic activity (P<0.05) and decreased lactic acid production (P<0.05). The quantitative polymerase chain reaction (qPCR) results showed that the expression of gtfB, gtfC and gtfD decreased when mass fractions of DMADDM increased (P<0.05). EPS staining showed that both the bacteria and EPS in biofilm decreased in the DMADDM groups. The incorporation of DMADDM could modify the properties of GIC to influence the development of S. mutans biofilms. In this study, we investigated the interface properties of antibacterial materials for the first time. GIC containing DMADDM can improve material performance and antibacterial properties and may contribute to the better management of secondary caries.}, } @article {pmid27357031, year = {2016}, author = {Lamas, A and Fernandez-No, IC and Miranda, JM and Vázquez, B and Cepeda, A and Franco, CM}, title = {Biofilm Formation and Morphotypes of Salmonella enterica subsp.arizonae Differs from Those of Other Salmonella enterica Subspecies in Isolates from Poultry Houses.}, journal = {Journal of food protection}, volume = {79}, number = {7}, pages = {1127-1134}, doi = {10.4315/0362-028X.JFP-15-568}, pmid = {27357031}, issn = {1944-9097}, mesh = {Animals ; Biofilms ; Cellulose/biosynthesis ; Poultry/*metabolism ; Salmonella/isolation & purification ; Salmonella enterica/*genetics ; }, abstract = {Salmonella serovars are responsible for foodborne diseases around the world. The ability to form biofilms allows microorganisms to survive in the environment. In this study, 73 Salmonella strains, belonging to four different subspecies, were isolated from poultry houses and foodstuffs and tested. Biofilm formation was measured at four different temperatures and two nutrient concentrations. Morphotypes and cellulose production were evaluated at three different temperatures. The presence of several genes related to biofilm production was also examined. All strains and subspecies of Salmonella had the ability to form biofilms, and 46.57% of strains produced biofilms under all conditions tested. Biofilm formation was strain dependent and varied according to the conditions. This is the first study to analyze biofilm formation in a wide number of Salmonella enterica subsp. arizonae strains, and no direct relationship between the high prevalence of Salmonella enterica subsp. arizonae strains and their ability to form biofilm was established. Morphotypes and cellulose production varied as the temperature changed, with 20°C being the optimum temperature for expression of the red, dry, and rough morphotype and cellulose. Salmonella enterica subsp. arizonae, whose morphotype is poorly studied, only showed a smooth and white morphotype and lacked the csgD and gcpA genes that are implicated in biofilm production. Thus, Salmonella biofilm formation under different environmental conditions is a public health problem because it can survive and advance through the food chain to reach the consumer.}, } @article {pmid27356028, year = {2016}, author = {Keelara, S and Thakur, S and Patel, J}, title = {Biofilm Formation by Environmental Isolates of Salmonella and Their Sensitivity to Natural Antimicrobials.}, journal = {Foodborne pathogens and disease}, volume = {13}, number = {9}, pages = {509-516}, doi = {10.1089/fpd.2016.2145}, pmid = {27356028}, issn = {1556-7125}, mesh = {Acrolein/analogs & derivatives/pharmacology ; Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Environmental Microbiology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; North Carolina ; Oils, Volatile/*pharmacology ; Salmonella enterica/classification/isolation & purification/*physiology ; Swine/microbiology ; }, abstract = {The objective of this study was to determine reduction of Salmonella in biofilms by essential oils. Biofilm formation of 15 Salmonella isolates from conventional swine farm environment was evaluated by 96-well microtiter plate crystal violet and minimum biofilm eradication concentration (MBEC) assays. Only one of the 15 isolates was a strong biofilm producer as classified by crystal violet assay. All Salmonella isolates formed biofilm on MBEC assay. The curli expression was robust among strains S322 and S435 (Salmonella Infantis), S644, S777, S931, S953, and S977 (Salmonella Typhimurium) as observed by Congo red dye binding assay. The cell hydrophobicity varied with strains and growth phase of the strain; however, there was no significant difference in hydrophobicity of these strains. Natural antimicrobials were evaluated with MBEC assay for their bactericidal efficacy in reducing Salmonella in biofilms. Cinnamaldehyde and sporran at 1000 ppm significantly reduced Salmonella in biofilms. The bactericidal effect of these antimicrobials increased with their concentrations. Salmonella were reduced by 6 log CFU from their initial populations of 7-7.5 log CFU/cm(2) when 2000 ppm concentration of these antimicrobials were used. Salmonella were undetectable when 3000 ppm of cinnamaldehyde or sporran was used. Natural antimicrobials such as cinnamaldehyde and sporran can be used to reduce Salmonella in biofilms.}, } @article {pmid27355936, year = {2016}, author = {Verderosa, AD and Mansour, SC and de la Fuente-Núñez, C and Hancock, RE and Fairfull-Smith, KE}, title = {Synthesis and Evaluation of Ciprofloxacin-Nitroxide Conjugates as Anti-Biofilm Agents.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {7}, pages = {}, pmid = {27355936}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/chemical synthesis/*chemistry/*pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Nitric Oxide/*chemistry ; Pseudomonas aeruginosa/drug effects ; }, abstract = {As bacterial biofilms are often refractory to conventional antimicrobials, the need for alternative and/or novel strategies for the treatment of biofilm related infections has become of paramount importance. Herein, we report the synthesis of novel hybrid molecules comprised of two different hindered nitroxides linked to the piperazinyl secondary amine of ciprofloxacin via a tertiary amine linker achieved utilising reductive amination. The corresponding methoxyamine derivatives were prepared alongside their radical-containing counterparts as controls. Subsequent biological evaluation of the hybrid compounds on preformed P. aeruginosa flow cell biofilms divulged significant dispersal and eradication abilities for ciprofloxacin-nitroxide hybrid compound 10 (up to 95% eradication of mature biofilms at 40 μM). Importantly, these hybrids represent the first dual-action antimicrobial-nitroxide agents, which harness the dispersal properties of the nitroxide moiety to circumvent the well-known resistance of biofilms to treatment with antimicrobial agents.}, } @article {pmid27354487, year = {2016}, author = {Arzmi, MH and Alnuaimi, AD and Dashper, S and Cirillo, N and Reynolds, EC and McCullough, M}, title = {Polymicrobial biofilm formation by Candida albicans, Actinomyces naeslundii, and Streptococcus mutans is Candida albicans strain and medium dependent.}, journal = {Medical mycology}, volume = {54}, number = {8}, pages = {856-864}, doi = {10.1093/mmy/myw042}, pmid = {27354487}, issn = {1460-2709}, mesh = {Actinomyces/growth & development/metabolism/*physiology ; Biofilms/*growth & development ; Candida albicans/growth & development/metabolism/*physiology ; Culture Media/*chemistry ; Formazans/analysis ; Gentian Violet/analysis ; *Microbial Interactions ; Models, Biological ; Saliva/microbiology ; Staining and Labeling ; Streptococcus mutans/growth & development/metabolism/*physiology ; }, abstract = {Oral biofilms comprise of extracellular polysaccharides and polymicrobial microorganisms. The objective of this study was to determine the effect of polymicrobial interactions of Candida albicans, Actinomyces naeslundii, and Streptococcus mutans on biofilm formation with the hypotheses that biofilm biomass and metabolic activity are both C. albicans strain and growth medium dependent. To study monospecific biofilms, C. albicans, A. naeslundii, and S. mutans were inoculated into artificial saliva medium (ASM) and RPMI-1640 in separate vials, whereas to study polymicrobial biofilm formation, the inoculum containing microorganisms was prepared in the same vial prior inoculation into a 96-well plate followed by 72 hours incubation. Finally, biofilm biomass and metabolic activity were measured using crystal violet and XTT assays, respectively. Our results showed variability of monospecies and polymicrobial biofilm biomass between C. albicans strains and growth medium. Based on cut-offs, out of 32, seven RPMI-grown biofilms had high biofilm biomass (HBB), whereas, in ASM-grown biofilms, 14 out of 32 were HBB. Of the 32 biofilms grown in RPMI-1640, 21 were high metabolic activity (HMA), whereas in ASM, there was no biofilm had HMA. Significant differences were observed between ASM and RPMI-grown biofilms with respect to metabolic activity (P <01). In conclusion, biofilm biomass and metabolic activity were both C. albicans strain and growth medium dependent.}, } @article {pmid27353754, year = {2016}, author = {Stuart, RK and Mayali, X and Boaro, AA and Zemla, A and Everroad, RC and Nilson, D and Weber, PK and Lipton, M and Bebout, BM and Pett-Ridge, J and Thelen, MP}, title = {Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm.}, journal = {mBio}, volume = {7}, number = {3}, pages = {}, pmid = {27353754}, issn = {2150-7511}, mesh = {Biofilms/growth & development/*radiation effects ; Carbon/chemistry/*metabolism ; Cyanobacteria/*metabolism ; Isotopes ; *Light ; Micronutrients/metabolism ; Nitrogen/chemistry/*metabolism ; Photosynthesis ; Polymers/metabolism ; Polysaccharides, Bacterial/*metabolism ; Proteome ; Single-Cell Analysis ; }, abstract = {UNLABELLED: Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption. Cyanobacteria in phototrophic biofilms can reuse extracellular organic carbon, but the metabolic drivers of extracellular processes are surprisingly complex. We investigated the metabolic foundations of organic matter reuse by comparing exoproteome composition and incorporation of (13)C-labeled and (15)N-labeled cyanobacterial extracellular organic matter (EOM) in a unicyanobacterial biofilm incubated using different light regimes. In the light and the dark, cyanobacterial direct organic C assimilation accounted for 32% and 43%, respectively, of all organic C assimilation in the community. Under photosynthesis conditions, we measured increased excretion of extracellular polymeric substances (EPS) and proteins involved in micronutrient transport, suggesting that requirements for micronutrients may drive EOM assimilation during daylight hours. This interpretation was supported by photosynthesis inhibition experiments, in which cyanobacteria incorporated N-rich EOM-derived material. In contrast, under dark, C-starved conditions, cyanobacteria incorporated C-rich EOM-derived organic matter, decreased excretion of EPS, and showed an increased abundance of degradative exoproteins, demonstrating the use of the extracellular domain for C storage. Sequence-structure modeling of one of these exoproteins predicted a specific hydrolytic activity that was subsequently detected, confirming increased EOM degradation in the dark. Associated heterotrophic bacteria increased in abundance and upregulated transport proteins under dark relative to light conditions. Taken together, our results indicate that biofilm cyanobacteria are successful competitors for organic C and N and that cyanobacterial nutrient and energy requirements control the use of EOM.

IMPORTANCE: Cyanobacteria are globally distributed primary producers, and the fate of their fixed C influences microbial biogeochemical cycling. This fate is complicated by cyanobacterial degradation and assimilation of organic matter, but because cyanobacteria are assumed to be poor competitors for organic matter consumption, regulation of this process is not well tested. In mats and biofilms, this is especially relevant because cyanobacteria produce an extensive organic extracellular matrix, providing the community with a rich source of nutrients. Light is a well-known regulator of cyanobacterial metabolism, so we characterized the effects of light availability on the incorporation of organic matter. Using stable isotope tracing at the single-cell level, we quantified photoautotroph assimilation under different metabolic conditions and integrated the results with proteomics to elucidate metabolic status. We found that cyanobacteria effectively compete for organic matter in the light and the dark and that nutrient requirements and community interactions contribute to cycling of extracellular organic matter.}, } @article {pmid27353218, year = {2016}, author = {Techaruvichit, P and Takahashi, H and Kuda, T and Miya, S and Keeratipibul, S and Kimura, B}, title = {Adaptation of Campylobacter jejuni to biocides used in the food industry affects biofilm structure, adhesion strength, and cross-resistance to clinical antimicrobial compounds.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {827-839}, doi = {10.1080/08927014.2016.1198476}, pmid = {27353218}, issn = {1029-2454}, mesh = {Adaptation, Physiological/*drug effects ; Anti-Infective Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Campylobacter jejuni/*physiology ; Disinfectants/*pharmacology ; *Drug Resistance, Bacterial ; *Food Industry ; Humans ; Microbial Sensitivity Tests ; Surface Properties ; }, abstract = {The emergence of biocide-adapted Campylobacter jejuni strains that developed into biofilms and their potential to develop clinical resistance to antimicrobial compounds was studied. C. jejuni was grown in sub-lethal concentrations of five biocides used in the food industry. C. jejuni exhibited adaptation to these biocides with increased minimum inhibitory concentrations. The 3-D structures of the biofilms produced by the biocide-adapted cells were investigated by atomic force microscopy (AFM). The results revealed marked variability in biofilm architecture, including ice-crystal-like structures. Adaptation to the biocides enhanced biofilm formation, with significant increases in biovolume, surface coverage, roughness, and the surface adhesion force of the biofilms. Adaptation to commercial biocides induced resistance to kanamycin and streptomycin. This study suggests that the inappropriate use of biocides may lead to cells being exposed to them at sub-lethal concentrations, which can result in adaptation of the pathogens to the biocides and a subsequent risk to public health.}, } @article {pmid27353168, year = {2017}, author = {Mirani, ZA and Naz, S and Khan, F and Aziz, M and Asadullah, and Khan, MN and Khan, SI}, title = {Antibacterial fatty acids destabilize hydrophobic and multicellular aggregates of biofilm in S. aureus.}, journal = {The Journal of antibiotics}, volume = {70}, number = {2}, pages = {115-121}, pmid = {27353168}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Fatty Acids/*pharmacology ; Hydrophobic and Hydrophilic Interactions ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Oxacillin/pharmacology ; }, abstract = {Present study is based on 20 methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered from different food items. These isolates were identified on the basis of colony morphology, Gram staining and growth on different selective and differential media. Studies on 16S RNA and positive reactions on DNase agar and Prolex Latex Agglutination system confirm it as Staphylococcus aureus. Oxacillin susceptibility testing and PCR with mecA gene-specific primer results showed that these isolates are MRSA-carrying mecA gene that belongs to SCCmecA type IV and also harbor agr type II. Phenotypic study revealed that these isolates adopt biofilm mode of growth after exposure to subinhibitory doses of oxacillin. The biofilm and cell surface hydrophobicity have a strong correlation. It was noticed that affinity to hexadecane (apolar-solvent) of planktonic cells was low, suggesting its hydrophilic character. However, as the cells are exposed to oxacillin, they adopt biofilm mode of life and the affinity to apolar solvent increases, indicating a hydrophobic character. In biofilm consortia, the cells with more hydrophobic surfaces show incomplete septation and produce multicellular aggregates. This is due to reduced expression of atl gene. This was confirmed by real-time PCR studies. Moreover, the planktonic or wild-type phenotypes of these isolates were more tolerant to antibacterial effect of the fatty acids used; that is, cis-2-decanoic acid and cis-9-octadectanoic acid. These fatty acids were more effective against biofilms. After exposure to these fatty acids, established biofilms were dispersed and surviving cells were unable to readopt biofilm mode of life. The planktonic or wild-type phenotypes produce fatty acid-modifying enzyme (FAME) to inactivate the bactericidal activity of fatty acids by esterification to cholesterol. The biofilm indwellers are metabolically inactive and unable to produce FAME; hence, they are vulnerable to antibiofilm effect of cis-2-decanoic acid and cis-9-octadectanoic acid.}, } @article {pmid27353113, year = {2016}, author = {Kyoui, D and Hirokawa, E and Takahashi, H and Kuda, T and Kimura, B}, title = {Effect of glucose on Listeria monocytogenes biofilm formation, and assessment of the biofilm's sanitation tolerance.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {815-826}, doi = {10.1080/08927014.2016.1198953}, pmid = {27353113}, issn = {1029-2454}, mesh = {Bacterial Load ; Biofilms/*drug effects ; *Drug Resistance, Bacterial ; Food-Processing Industry ; Glucose/*administration & dosage ; Humans ; Listeria monocytogenes/drug effects/*physiology ; Microscopy, Atomic Force ; Sanitation ; Sodium Hypochlorite/*pharmacology ; Time Factors ; }, abstract = {Listeria monocytogenes is an important cause of human foodborne infections and its ability to form biofilms is a serious concern to the food industry. To reveal the effect of glucose conditions on biofilm formation of L. monocytogenes, 20 strains were investigated under three glucose conditions (0.1, 1.0, and 2.0% w v(-1)) by quantifying the number of cells in the biofilm and observing the biofilm structure after incubation for 24, 72, and 168 h. In addition, the biofilms were examined for their sensitivity to sodium hypochlorite. It was found that high concentrations of glucose reduced the number of viable cells in the biofilms and increased extracellular polymeric substance production. Moreover, biofilms formed at a glucose concentration of 1.0 or 2.0% were more resistant to sodium hypochlorite than those formed at a glucose concentration of 0.1%. This knowledge can be used to help design the most appropriate sanitation strategy.}, } @article {pmid27352339, year = {2015}, author = {Chen, Y and Wang, XY and Huang, YC and Zhao, GQ and Lei, YJ and Ye, LH and Huang, QB and Duan, WS}, title = {Study on the Structure of Candida Albicans-Staphylococcus Epidermidis Mixed Species Biofilm on Polyvinyl Chloride Biomaterial.}, journal = {Cell biochemistry and biophysics}, volume = {73}, number = {2}, pages = {461-468}, doi = {10.1007/s12013-015-0672-y}, pmid = {27352339}, issn = {1559-0283}, mesh = {Biocompatible Materials/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*physiology ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Models, Biological ; Polyvinyl Chloride/chemistry/*pharmacology ; Staphylococcus epidermidis/*physiology ; }, abstract = {The objective of the study was to establish an in vitro model of Candida albicans-Staphylococcus epidermidis mixed species biofilm (BF) on polyvinyl chloride (PVC) material, and to investigate the formation and the structure of mixed species BF formation using a combined approach of confocal laser scanning microscope (CLSM), scanning electron microscope (SEM), and 3D image reconstruction technique. Mixed species BF is achieved by co-incubating Staphylococcus epidermidis bacteria (ATCC35984) and Candida albicans fungal (ATCC10231) with PVC pieces in Tris-buffered saline. BF formation was examined at 2, 6, 12, 24, 48, and 72 h of co-culture. Thickness of these BFs and the number, and percentage of viable cells in BFs were measured. CT scan images of BFs were obtained using CLSM and SEM and reconstructed 3D images of mixed species BF were acquired, in an effort to examine structure of the BF. Staphylococcus epidermidis attached to various forms of candida albicans (spores, pseudohyphae, and hyphae), formed complex and dense mesh arrays. The BF is constituted of a large number of viable and dead pathogens, the surface of mixed species BF is uneven, with living pathogens predominating protrusive portions and dead pathogens aggregating in concaves. Mixed species BF formation on the surface of PVC material was found to be a dynamic process, with rapid growth being at 24 h of co-culture, maximal thickness peaked at 48 h. These mixed species BF matured at 48-72 h. Significant differences were observed in the proportion of viable cells between interior, middle, and outer layers of BFs (p < 0.05). Mixed species BF Candida albicans-Staphylococcus epidermidis is sophisticated in structure. The combined approach involving CLSM, SEM, and 3D image reconstruction technique is ideal for the investigation of mixed species BF on PVC material.}, } @article {pmid27351824, year = {2016}, author = {Maisetta, G and Grassi, L and Di Luca, M and Bombardelli, S and Medici, C and Brancatisano, FL and Esin, S and Batoni, G}, title = {Anti-biofilm properties of the antimicrobial peptide temporin 1Tb and its ability, in combination with EDTA, to eradicate Staphylococcus epidermidis biofilms on silicone catheters.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {787-800}, doi = {10.1080/08927014.2016.1194401}, pmid = {27351824}, issn = {1029-2454}, mesh = {Anti-Infective Agents/administration & dosage/*pharmacology ; Antimicrobial Cationic Peptides ; Biofilms/*drug effects ; Catheters/*microbiology ; Edetic Acid/administration & dosage/*pharmacology ; Humans ; Kinetics ; Microbial Sensitivity Tests ; Proteins/administration & dosage/*pharmacology ; Silicones/*chemistry ; Staphylococcus epidermidis/*drug effects/physiology ; }, abstract = {In search of new antimicrobials with anti-biofilm potential, in the present study activity of the frog-skin derived antimicrobial peptide temporin 1Tb (TB) against Staphylococcus epidermidis biofilms was investigated. A striking ability of TB to kill both forming and mature S. epidermidis biofilms was observed, especially when the peptide was combined with cysteine or EDTA, respectively. Kinetics studies demonstrated that the combination TB/EDTA was active against mature biofilms already after 2-4-h exposure. A double 4-h exposure of biofilms to TB/EDTA further increased the therapeutic potential of the same combination. Of note, TB/EDTA was able to eradicate S. epidermidis biofilms formed in vitro on silicone catheters. At eradicating concentrations, TB/EDTA did not cause hemolysis of human erythrocytes. The results shed light on the anti-biofilm properties of TB and suggest a possible application of the peptide in the lock therapy of catheters infected with S. epidermidis.}, } @article {pmid27348759, year = {2016}, author = {Yang, JL and Li, YF and Guo, XP and Liang, X and Xu, YF and Ding, DW and Bao, WY and Dobretsov, S}, title = {The effect of carbon nanotubes and titanium dioxide incorporated in PDMS on biofilm community composition and subsequent mussel plantigrade settlement.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {763-777}, doi = {10.1080/08927014.2016.1197210}, pmid = {27348759}, issn = {1029-2454}, mesh = {Animals ; Biofilms/*growth & development ; Diatoms/*physiology ; Dimethylpolysiloxanes/*chemistry ; Mytilus/*physiology ; Nanotubes, Carbon/*chemistry ; Proteobacteria/*physiology ; Surface Properties ; Titanium/*chemistry ; }, abstract = {This study investigated the effect of carbon nanotubes (CNTs) and titanium dioxide (TiO2) incorporated in PDMS on biofilm formation and plantigrade settlement of Mytilus coruscus. TiO2 increased bacterial density, and CNTs also increased bacterial density but reduced diatom density in biofilms after 28 days. Further analysis was conducted between bacterial communities on glass, PDMS, CNTs (0.5 wt%) and TiO2 (7.5 wt%). ANOSIM analysis revealed significant differences (R > 0.9) between seven, 14, 21 and 28 day-old bacterial communities. MiSeq sequencing showed that CNTs and TiO2 impacted the composition of 28 day-old bacterial communities by increasing the abundance of Proteobacteria and decreasing the abundance of Bacteroidetes. The maximum decreased settlement rate in 28 day-old biofilms on CNTs and TiO2 was > 50% in comparison to those on glass and PDMS. Thus, CNTs and TiO2 incorporated in PDMS altered the biomass and community composition of biofilms, and subsequently decreased mussel settlement.}, } @article {pmid27348605, year = {2016}, author = {Duan, D and Scoffield, JA and Zhou, X and Wu, H}, title = {Fine-tuned production of hydrogen peroxide promotes biofilm formation of Streptococcus parasanguinis by a pathogenic cohabitant Aggregatibacter actinomycetemcomitans.}, journal = {Environmental microbiology}, volume = {18}, number = {11}, pages = {4023-4036}, pmid = {27348605}, issn = {1462-2920}, support = {R01 DE017954/DE/NIDCR NIH HHS/United States ; R01 DE022350/DE/NIDCR NIH HHS/United States ; }, mesh = {Aggregatibacter actinomycetemcomitans/genetics/*metabolism ; Bacterial Proteins/genetics/metabolism ; *Biofilms/growth & development ; Gene Expression Regulation, Bacterial ; Hydrogen Peroxide/*metabolism ; Streptococcus/genetics/*physiology ; }, abstract = {Balanced bacterial biofilm communities help to maintain host health. Disturbance of such balance can lead to bacterial dysbiosis and pathogenesis. However, complex and dynamic bacterial interactions within the biofilm communities are poorly understood. In this study, we used a dual-species biofilm consisting of the periodontal pathogen Aggregatibacter actinomycetemcomitans, and a commensal Streptococcus parasanguinis to investigate bacterial interactions since the two organisms have been found to coexist during the development of localized aggressive periodontal disease. We report that A. actinomycetemcomitans promoted biofilm formation of S. parasanguinis in vitro and in vivo. Protein profiling of S. parasanguinis co-cultured with A. actinomycetemcomitans revealed a significant decrease in the protein level of pyruvate oxidase(PoxL), an enzyme required for the generation of hydrogen peroxide (H2 O2). Consistently, the H2 O2 concentration was concurrently decreased. However, the complete removal of H2 O2 impaired the biofilm formation. H2 O2 at a low concentration range regulated by A. actinomycetemcomitans enhanced the biofilm formation. These results demonstrate that A. actinomycetemcomitans promotes the S. parasanguinis biofilm formation through modulating the production of H2 O2 by fine-tuning the expression of poxL, indicating that H2 O2 functions as a signaling molecule. Taken together, this report revealed a previously unknown bacteria-bacteria interaction mechanism.}, } @article {pmid27347641, year = {2016}, author = {Kissoyan, KA and Bazzi, W and Hadi, U and Matar, GM}, title = {The inhibition of Pseudomonas aeruginosa biofilm formation by micafungin and the enhancement of antimicrobial agent effectiveness in BALB/c mice.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {779-786}, doi = {10.1080/08927014.2016.1199021}, pmid = {27347641}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/*pharmacology/therapeutic use ; Biofilms/*drug effects/growth & development ; Candida albicans/physiology ; Drug Therapy, Combination ; Echinocandins/administration & dosage/*pharmacology/therapeutic use ; Levofloxacin/administration & dosage/therapeutic use ; Lipopeptides/administration & dosage/*pharmacology/therapeutic use ; Male ; Micafungin ; Mice ; Mice, Inbred BALB C ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/*physiology ; Survival Analysis ; beta-Glucans/antagonists & inhibitors ; }, abstract = {Micafungin inhibits biofilm formation by impeding 1,3-β-D-glucan synthesis in Candida albicans. Since Pseudomonas aeruginosa also has 1,3-β-D-glucan in its cell wall, this study assessed the effects of antibacterial agents in vitro and in vivo on micafungin-treated biofilm-forming P. aeruginosa isolates. After treatment with micafungin as well as with a panel of four antibacterial agents, biofilm production was significantly reduced as measured by spectrophotometry. The relative mRNA transcription levels for the genes encoding pellicles (pelC) and cell wall 1,3-β-D-glucan (ndvB), which were measured by quantitative reverse transcription PCR (qRT-PCR), significantly decreased with micafungin treatment. In vivo, the survival rates of P. aeruginosa-infected BALB/c mice significantly increased after combined treatment with micafungin and each of the antibacterial agents. Of these treatments, the combination of micafungin with levofloxacin had the highest survival rate; this combination was the most effective treatment against P. aeruginosa-induced infection.}, } @article {pmid27346839, year = {2016}, author = {Tan, Y and Leonhard, M and Moser, D and Ma, S and Schneider-Stickler, B}, title = {Long-term antibiofilm activity of carboxymethyl chitosan on mixed biofilm on silicone.}, journal = {The Laryngoscope}, volume = {126}, number = {12}, pages = {E404-E408}, doi = {10.1002/lary.26096}, pmid = {27346839}, issn = {1531-4995}, mesh = {Biofilms/*drug effects ; Candida/drug effects/ultrastructure ; Chitosan/*analogs & derivatives/pharmacology ; Gram-Positive Bacteria/drug effects/ultrastructure ; Larynx, Artificial/*microbiology ; Microscopy, Electron, Scanning ; *Silicones ; }, abstract = {OBJECTIVES/HYPOTHESIS: Silicone voice prostheses are most frequently used in voice rehabilitation of laryngectomized patients. However, the functional device lifetimes are limited due to formation of mixed biofilms. Existing in vitro models simulating biofilm formation are restricted to only short-term periods.

STUDY DESIGN: The goal of this study was to determine the effect of carboxymethyl chitosan on mixed biofilm formation of fungi and bacteria on silicone over a long-term period.

METHODS: Mixed species biofilms of Candida albicans, Candida tropicalis, Lactobacillus gasseri, Streptococcus salivarius, Rothia dentocariosa, and Staphylococcus epidermidis were cultivated on the surfaces of medical-grade silicone with and without addition of carboxymethyl chitosan. Biofilm kinetics was monitored using specially designed image analysis software to calculate the percentual surface covering of each platelet. Biofilm architecture was investigated by scanning electron microscopy.

RESULTS: A cover of living mixed biofilm could be generated over 22 days on silicone and the maximum of 22% biofilm surface covering at day 22. However, less than 4% surface coverage was observed on the carboxymethyl chitosan-treated plates in the testing period. Scanning electron microscopy confirms that, on surfaces treated by carboxymethyl chitosan, the biofilm was less dense. In addition, there were fewer layers of cells and profuse cellular debris, together with degrading and morphologically altered yeast cells.

CONCLUSION: Carboxymethyl chitosan may serve as a possible antibiofilm agent to limit biofilm formation on voice prostheses.

LEVEL OF EVIDENCE: NA Laryngoscope, 126:E404-E408, 2016.}, } @article {pmid27346417, year = {2016}, author = {Cierech, M and Kolenda, A and Grudniak, AM and Wojnarowicz, J and Woźniak, B and Gołaś, M and Swoboda-Kopeć, E and Łojkowski, W and Mierzwińska-Nastalska, E}, title = {Significance of polymethylmethacrylate (PMMA) modification by zinc oxide nanoparticles for fungal biofilm formation.}, journal = {International journal of pharmaceutics}, volume = {510}, number = {1}, pages = {323-335}, doi = {10.1016/j.ijpharm.2016.06.052}, pmid = {27346417}, issn = {1873-3476}, mesh = {Antifungal Agents/administration & dosage/*chemistry ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/growth & development ; Humans ; Nanoparticles/administration & dosage/*chemistry ; Polymethyl Methacrylate/administration & dosage/*chemistry ; Zinc Oxide/administration & dosage/*chemistry ; }, abstract = {The objective of this study was to obtain a material composite with antifungal properties for dentures to be used as an alternative protocol in denture stomatitis treatment and prevention. Denture stomatitis is still a clinical problem in patients particularly vulnerable to this disease. Composites of PMMA and doped ZnO-NPs (weight concentrations, 2.5%, 5%, 7.5%) and PMMA with sprayed solvothermal and hydrothermal ZnO-NPs were tested. The following investigations of newly formed biomaterials were undertaken: influence on Candida albicans solution, biofilm staining, XTT analysis and a quantitative analysis of adhered C. albicans. These studies evidenced the antifungal activity of both nanocomposites PMMA-ZnO-NPs and the efficacy of sputtering of zinc oxide nanoparticles on the PMMA. The study of the biofilm deposition on the surface showed that antifungal properties increase with increasing concentration of ZnO-NPs. The XTT assay in conjunction with testing the turbidity of solutions may indicate the mechanism by which ZnO-NPs exert their effect on the increased induction of antioxidative stress in microorganism cells. The denture base made of the aforesaid materials may play a preventive role in patients susceptible to fungal infections. Based on the results obtained a modified treatment of stomatitis Type II (Newton's classification) complicated by fungal infection was proposed.}, } @article {pmid27345713, year = {2016}, author = {da Costa Luciano, C and Olson, N and DeGagne, P and Franca, R and Tipple, AFV and Alfa, M}, title = {A new buildup biofilm model that mimics accumulation of material in flexible endoscope channels.}, journal = {Journal of microbiological methods}, volume = {127}, number = {}, pages = {224-229}, doi = {10.1016/j.mimet.2016.06.022}, pmid = {27345713}, issn = {1872-8359}, mesh = {*Biofilms ; Colony Count, Microbial ; Detergents/pharmacology ; Disinfectants/pharmacology ; Disinfection/methods ; Endoscopes/*microbiology ; Enterococcus faecalis/isolation & purification/physiology ; *Equipment Contamination/prevention & control ; Glutaral/pharmacology ; Humans ; Hydrogen Peroxide/pharmacology ; Microscopy, Electron, Scanning ; *Models, Biological ; Pseudomonas aeruginosa/isolation & purification/physiology ; }, abstract = {The objective of this study was to develop a new build up biofilm (BBF) model that was based on repeated exposure to test soil containing Enterococcus faecalis and Pseudomonas aeruginosa and repeated rounds of fixation to mimic the accumulation of patient material in endoscope channels during reprocessing. The new BBF model is a novel adaptation of the minimum biofilm effective concentration (MBEC) 96-well model where biofilm is formed on plastic pegs. The new MBEC-BBF model was developed over eight days and included four rounds of partial fixation using glutaraldehyde. There was 6.14Log10cfu/cm(2) of E. faecalis and 7.71Log10cfu/cm(2) of P. aeruginosa in the final BBF. Four detergents (two enzymatic and two non-enzymatic) were tested alone or in combination with orthophthalaldehyde, glutaraldehyde or accelerated hydrogen peroxide to determine if BBF could be either removed or the bacteria within the BBF killed. None of the detergents alone could remove the biofilm or reduce the bacterial level in the BBF as determined by viable count and scanning electron microscopy. The combination of detergents and disinfectants tested provided a 3 to 5Log10 reduction in viable bacteria but no combination could provide the expected 6Log10 reduction. Our data indicated that once formed BBF was extremely difficult to eliminate. Future research using the BBF model may help develop new cleaning and disinfection methods that can prevent or eliminate BBF within endoscope channels.}, } @article {pmid27344542, year = {2016}, author = {Pinheiro, L and Brito, CI and Oliveira, Ad and Pereira, VC and Cunha, Mde L}, title = {Staphylococcus epidermidis and Staphylococcus haemolyticus: detection of biofilm genes and biofilm formation in blood culture isolates from patients in a Brazilian teaching hospital.}, journal = {Diagnostic microbiology and infectious disease}, volume = {86}, number = {1}, pages = {11-14}, doi = {10.1016/j.diagmicrobio.2016.06.006}, pmid = {27344542}, issn = {1879-0070}, mesh = {Bacteremia/*microbiology ; Bacterial Adhesion ; Biofilms/*growth & development ; Brazil ; *Genes, Bacterial ; Hospitals, Teaching ; Humans ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/genetics/isolation & purification/*physiology ; Staphylococcus haemolyticus/genetics/isolation & purification/*physiology ; }, abstract = {Infections with coagulase-negative staphylococci are often related to biofilm formation. This study aimed to detect biofilm formation and biofilm-associated genes in blood culture isolates of Staphylococcus epidermidis and S. haemolyticus. Half (50.6%) of the 85 S. epidermidis isolates carried the icaAD genes and 15.3% the bhp gene, while these numbers were 42.9% and 0 for S. haemolyticus, respectively. According to the plate test, 30 S. epidermidis isolates were biofilm producers and 40% of them were strongly adherent, while only one (6%) of the 17 S. haemolyticus biofilm-producing isolates exhibited a strongly adherent biofilm. The concomitant presence of icaA and icaD was significantly associated with the plate and tube test results (P ≤ 0.0004). The higher frequency of icaA in S. epidermidis and of icaD in S. haemolyticus is correlated with the higher biofilm-producing capacity of the former since, in contrast to IcaD, IcaA activity is sufficient to produce small amounts of polysaccharide. Although this study emphasizes the importance of icaAD and bhp for biofilm formation in S. epidermidis, other mechanisms seem to be involved in S. haemolyticus.}, } @article {pmid27344424, year = {2016}, author = {Buhmann, MT and Stiefel, P and Maniura-Weber, K and Ren, Q}, title = {In Vitro Biofilm Models for Device-Related Infections.}, journal = {Trends in biotechnology}, volume = {34}, number = {12}, pages = {945-948}, doi = {10.1016/j.tibtech.2016.05.016}, pmid = {27344424}, issn = {1879-3096}, mesh = {*Biofilms ; Biomedical Research/*methods ; Humans ; *Models, Biological ; *Prosthesis-Related Infections ; }, abstract = {Many promising antimicrobial materials fail to translate from bench to bedside, in part owing to a lack of in vitro biofilm models that can be used to predict their long-term in vivo antimicrobial and anti-biofilm activity. Various factors need to be considered for predictive modeling to mimic the conditions in vivo.}, } @article {pmid27343453, year = {2016}, author = {Ruan, YJ and Deng, YL and Guo, XS and Timmons, MB and Lu, HF and Han, ZY and Ye, ZY and Shi, MM and Zhu, SM}, title = {Simultaneous ammonia and nitrate removal in an airlift reactor using poly(butylene succinate) as carbon source and biofilm carrier.}, journal = {Bioresource technology}, volume = {216}, number = {}, pages = {1004-1013}, doi = {10.1016/j.biortech.2016.06.056}, pmid = {27343453}, issn = {1873-2976}, mesh = {*Ammonia/analysis/chemistry/isolation & purification/metabolism ; *Biofilms ; *Bioreactors ; Butylene Glycols/*chemistry ; Denitrification ; *Nitrates/analysis/chemistry/isolation & purification/metabolism ; Nitrification ; Polymers/*chemistry ; }, abstract = {In this study, an airlift inner-loop sequencing batch reactor using poly(butylene succinate) as the biofilm carrier and carbon source was operated under an alternant aerobic/anoxic strategy for nitrogen removal in recirculating aquaculture system. The average TAN and nitrate removal rates of 47.35±15.62gNH4-Nm(-3)d(-1) and 0.64±0.14kgNO3-Nm(-3)d(-1) were achieved with no obvious nitrite accumulation (0.70±0.76mg/L) and the dissolved organic carbon in effluents was maintained at 148.38±39.06mg/L. Besides, the activities of dissimilatory nitrate reduction to ammonium and sulfate reduction activities were successfully inhibited. The proteome KEGG analysis illustrated that ammonia might be removed through heterotrophic nitrification, while the activities of nitrate and nitrite reductases were enhanced through aeration treatment. The microbial community analysis revealed that denitrifiers of Azoarcus and Simplicispira occupied the dominate abundance which accounted for the high nitrate removal performance. Overall, this study broadened our understanding of simultaneous nitrification and denitrification using biodegradable material as biofilm carrier.}, } @article {pmid27342552, year = {2016}, author = {Abberton, CL and Bereschenko, L and van der Wielen, PW and Smith, CJ}, title = {Survival, Biofilm Formation, and Growth Potential of Environmental and Enteric Escherichia coli Strains in Drinking Water Microcosms.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {17}, pages = {5320-5331}, pmid = {27342552}, issn = {1098-5336}, mesh = {*Biofilms ; Drinking Water/*microbiology ; Escherichia coli/genetics/*growth & development/isolation & purification/physiology ; Escherichia coli Proteins/genetics/metabolism ; Microbial Viability ; Water Microbiology ; }, abstract = {UNLABELLED: Escherichia coli is the most commonly used indicator for fecal contamination in drinking water distribution systems (WDS). The assumption is that E. coli bacteria are of enteric origin and cannot persist for long outside their host and therefore act as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water, specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric isolates and one soil isolate) in sterile and nonsterile drinking water microcosms at 8 and 17°C, with T90 (time taken for a reduction in cell number of 1 log10 unit) values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (reverse transcription-)quantitative PCR [(RT-)Q-PCR] assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dynes [dyn] cm(-2); BioFlux system; Fluxion); however, cell numbers did not increase when drinking water flowed over the biofilm (P > 0.05 by t test). Finally, E. coli regrowth within drinking water microcosms containing polyethylene PE-100 pipe wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely.

IMPORTANCE: The provision of clean, safe drinking water is fundamental to society. WDS deliver water to consumers via a vast network of pipes. E. coli is used as an indicator organism for recent contamination events based on the premise that it cannot survive for long outside its host. A key public health concern therefore arises around the fate of E. coli on entering a WDS; its survival, ability to form a biofilm, and potential for regrowth. In particular, if E. coli bacteria have the ability to incorporate and regrow within the pipe wall biofilm of a WDS, they could reinoculate the water at a later stage. This study sheds light on the fate of environmental and enteric strains of E. coli in drinking water showing extended survival, the potential for biofilm formation under shear stress, and importantly, that regrowth in the presence of an indigenous microbial community is unlikely.}, } @article {pmid27341798, year = {2016}, author = {Wang, X and Cai, Y and Xing, H and Wu, W and Wang, G and Li, L and Chen, J}, title = {Increased therapeutic efficacy of combination of azithromycin and ceftazidime on Pseudomonas aeruginosa biofilm in an animal model of ureteral stent infection.}, journal = {BMC microbiology}, volume = {16}, number = {1}, pages = {124}, pmid = {27341798}, issn = {1471-2180}, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; Azithromycin/*administration & dosage ; Biofilms/*drug effects ; Ceftazidime/*administration & dosage ; Disease Models, Animal ; Drug Synergism ; Drug Therapy, Combination ; Female ; Humans ; Microbial Sensitivity Tests ; Prosthesis-Related Infections/*drug therapy/microbiology ; Pseudomonas Infections/*drug therapy/microbiology ; Pseudomonas aeruginosa/*drug effects/physiology ; Rats ; Rats, Wistar ; Stents/*adverse effects ; }, abstract = {BACKGROUND: Infection caused by ureteral stent indwelling is one of the most difficult medical problems, since once bacteria reside in biofilms they are extremely resistant to antibiotics as well as to the host immune defences. In this study we assessed the in vitro and in vivo efficacy of azithromycin and ceftazidime in preventing ureteral stent infection by Pseudomonas aeruginosa.

RESULTS: The susceptibility testing with adherent bacteria showed that the biofilm was strongly inhibited by azithromycin treatment, ceftazidime against adherent bacteria in the presence of azithromycin showed the minimum inhibitory concentrations (MICs) and minimum bacteriocidal concentrations (MBCs) dramatically lower than those obtained in the absence of azithromycin. Moreover, ceftazidime plus azithromycin reduced twitching motility and production of rhamnolipid. For the single-treatment groups, in vivo intravenous injection of ceftazidime showed the highest inhibitory effect on bacterial load. Azithromycin prophylactic injection combined with ceftazidime showed increased inhibitory effect on bacterial load than that of each single antibiotic.

CONCLUSIONS: Combination of azithromycin and ceftazidime effectively prevent the formation of biofilm and reduced bacteria load of Pseudomonas aeruginosa compared to separate treatment of either of these two antibiotics. This combined treatment option have the potential to contribute to the success of Pseudomonas biofilm elimination in the clinical environment.}, } @article {pmid27341658, year = {2016}, author = {Stephens, MD and Yodsanit, N and Melander, C}, title = {Evaluation of ethyl N-(2-phenethyl) carbamate analogues as biofilm inhibitors of methicillin resistant Staphylococcus aureus.}, journal = {Organic & biomolecular chemistry}, volume = {14}, number = {28}, pages = {6853-6856}, pmid = {27341658}, issn = {1477-0539}, support = {R01 DE022350/DE/NIDCR NIH HHS/United States ; R01 GM055769/GM/NIGMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Carbamates/*chemistry/*pharmacology ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects/physiology ; Microbial Sensitivity Tests ; Small Molecule Libraries/chemistry/pharmacology ; Staphylococcal Infections/drug therapy ; }, abstract = {A small molecule library consisting of 45 compounds was synthesized based on the bacterial metabolite ethyl N-(2-phenethyl) carbamate. Screening of the compounds revealed a potent analogue capabale of inhibiting several strains of Methicillin Resistant S. aureus biofilms with low to moderate micromolar IC50 values.}, } @article {pmid27340170, year = {2016}, author = {Jafer, M and Patil, S and Hosmani, J and Bhandi, SH and Chalisserry, EP and Anil, S}, title = {Chemical Plaque Control Strategies in the Prevention of Biofilm-associated Oral Diseases.}, journal = {The journal of contemporary dental practice}, volume = {17}, number = {4}, pages = {337-343}, doi = {10.5005/jp-journals-10024-1851}, pmid = {27340170}, issn = {1526-3711}, mesh = {Aloe ; Benzhydryl Compounds/therapeutic use ; *Biofilms ; Cetylpyridinium/therapeutic use ; Chlorhexidine/therapeutic use ; Dental Plaque/*prevention & control ; Dextranase/therapeutic use ; Drug Combinations ; Humans ; Lippia ; Morpholines/therapeutic use ; Periodontal Diseases/etiology/*prevention & control ; Phenols/therapeutic use ; Plant Extracts/therapeutic use ; Povidone-Iodine/therapeutic use ; Propolis/therapeutic use ; Salicylates/therapeutic use ; Terpenes/therapeutic use ; }, abstract = {Dental plaque is a biofilm that forms naturally on the surfaces of exposed teeth and other areas of the oral cavity. It is the primary etiological factor for the most frequently occurring oral diseases, such as dental caries and periodontal diseases. Specific, nonspecific, and ecologic plaque hypothesis explains the causation of dental and associated diseases. Adequate control of biofilm accumulation on teeth has been the cornerstone of prevention of periodontitis and dental caries. Mechanical plaque control is the mainstay for prevention of oral diseases, but it requires patient cooperation and motivation; therefore, chemical plaque control agents act as useful adjuvants for achieving the desired results. Hence, it is imperative for the clinicians to update their knowledge in chemical antiplaque agents and other developments for the effective management of plaque biofilm-associated diseases. This article explores the critical analysis of various chemical plaque control strategies and the current trends in the control and prevention of dental plaque biofilm.}, } @article {pmid27339856, year = {2017}, author = {Moon, JH and Kim, M and Lee, JH}, title = {Genome sequence of Prevotella intermedia SUNY aB G8-9K-3, a biofilm forming strain with drug-resistance.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {48}, number = {1}, pages = {5-6}, pmid = {27339856}, issn = {1678-4405}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms ; Computational Biology/methods ; *Drug Resistance, Bacterial ; *Genome, Bacterial ; Genomics/methods ; *High-Throughput Nucleotide Sequencing ; Molecular Sequence Annotation ; Polymorphism, Single Nucleotide ; Prevotella intermedia/*drug effects/*physiology ; Sequence Analysis, DNA ; }, abstract = {Prevotella intermedia has long been known to be as the principal etiologic agent of periodontal diseases and associated with various systemic diseases. Previous studies showed that the intra-species difference exists in capacity of biofilm formation, antibiotic resistance, and serological reaction among P. intermedia strains. Here we report the genome sequence of P. intermedia SUNY aB G8-9K-3 (designated ATCC49046) that displays a relatively high antimicrobial resistant and biofilm-forming capacity. Genome sequencing information provides important clues in understanding the genetic bases of phenotypic differences among P. intermedia strains.}, } @article {pmid27339305, year = {2016}, author = {Schillaci, D and Spinello, A and Cusimano, MG and Cascioferro, S and Barone, G and Vitale, M and Arizza, V}, title = {A peptide from human β thymosin as a platform for the development of new anti-biofilm agents for Staphylococcus spp. and Pseudomonas aeruginosa.}, journal = {World journal of microbiology & biotechnology}, volume = {32}, number = {8}, pages = {124}, pmid = {27339305}, issn = {1573-0972}, mesh = {Amino Acid Sequence ; Anti-Infective Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms ; Humans ; Microbial Sensitivity Tests ; Models, Molecular ; Molecular Dynamics Simulation ; Peptides/*chemical synthesis/chemistry/*pharmacology ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; Structure-Activity Relationship ; Thymosin/chemistry/*genetics ; }, abstract = {Conventional antibiotics might fail in the treatment of biofilm-associated infections causing infection recurrence and chronicity. The search for antimicrobial peptides has been performed with the aim to discover novel anti-infective agents active on pathogens in both planktonic and biofilm associated forms. The fragment 9-19 of human thymosin β4 was studied through 1 μs MD simulation. Two main conformations of the peptide were detected, both constituted by a central hydrophobic core and by the presence of peripheral charged residues suggesting a possible mechanism of interaction with two models of biological membranes, related to eukaryotic or bacterial membrane respectively. In addition, the peptide was chemically synthesized and its antimicrobial activity was tested in vitro against planktonic and biofilm form of a group of reference strains of Staphylococcus spp. and one P. aeruginosa strain. The human thymosin β4 fragment EIEKFDKSKLK showed antibacterial activity against staphylococcal strains and Pseudomonas aeruginosa ATCC 15442 at concentrations from 12.5 to 6.2 mg/ml and inhibited biofilm formation at sub-inhibitory concentrations (3.1-0.75 mg/ml). The activity of the fragment in inhibiting biofilm formation, could be due to the conformations highlighted by the MD simulations, suggesting its interaction with the bacterial membrane. Human thymosin β4 fragment can be considered a promising lead compound to develop novel synthetic or recombinant derivatives with improved pharmaceutical potential.}, } @article {pmid27338651, year = {2016}, author = {Murphy, MF and Edwards, T and Hobbs, G and Shepherd, J and Bezombes, F}, title = {Acoustic vibration can enhance bacterial biofilm formation.}, journal = {Journal of bioscience and bioengineering}, volume = {122}, number = {6}, pages = {765-770}, doi = {10.1016/j.jbiosc.2016.05.010}, pmid = {27338651}, issn = {1347-4421}, mesh = {Bacterial Load/radiation effects ; Biofilms/*radiation effects ; Microbiological Techniques ; Pseudomonas aeruginosa/growth & development/*radiation effects ; *Sound ; Staphylococcus aureus/growth & development/*radiation effects ; *Vibration ; }, abstract = {This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes.}, } @article {pmid27337977, year = {2017}, author = {Esteves-Oliveira, M and El-Sayed, KF and Dörfer, C and Schwendicke, F}, title = {Impact of combined CO2 laser irradiation and fluoride on enamel and dentin biofilm-induced mineral loss.}, journal = {Clinical oral investigations}, volume = {21}, number = {4}, pages = {1243-1250}, pmid = {27337977}, issn = {1436-3771}, mesh = {Animals ; Bacterial Adhesion/drug effects/radiation effects ; Biofilms/*drug effects/*radiation effects ; Cattle ; Dental Enamel/*drug effects/*radiation effects ; Dentin/*drug effects/*radiation effects ; Fluorides, Topical/*pharmacology ; In Vitro Techniques ; *Lasers, Gas ; Microradiography ; Microscopy, Electron, Scanning ; Random Allocation ; Sodium Fluoride ; Streptococcus mutans/drug effects/radiation effects ; Surface Properties ; Tooth Demineralization/*prevention & control ; }, abstract = {OBJECTIVES: The caries-protective effects of CO2 laser irradiation on dental enamel have been demonstrated using chemical demineralization models. We compared the effect of CO2 laser irradiation, sodium fluoride, or both on biofilm-induced mineral loss (∆Z) and Streptococcus mutans adhesion to enamel and dentin in vitro.

MATERIALS AND METHODS: Ground, polished bovine enamel, and dentin samples were allocated to four groups (n = 12/group): no treatment (C); single 22,600-ppm fluoride (F) varnish (5 % NaF) application; single CO2 laser treatment (L) with short pulses (5 μs/λ = 10.6 μm); and laser and subsequent fluoride treatment (LF). Samples were sterilized and submitted to an automated mono-species S. mutans biofilm model. Brain heart infusion plus 5 % sucrose medium was provided eight times daily, followed by rinses with artificial saliva. After 10 days, bacterial numbers in biofilms were enumerated as colony-forming units/ml (CFU/ml) (n = 7/group). ∆Z was assessed using transversal microradiography (n = 12/group). Univariate ANOVA with post hoc Tukey honestly-significant-difference test was used for statistical analysis.

RESULTS: Bacterial numbers were significantly higher on dentin than enamel (p < 0.01/ANOVA). On dentin, LF yielded significantly lower CFUs than other groups (p = 0.03/Tukey), while no differences between groups were found for enamel. The lowest ∆Z in enamel was observed for L (mean/SD 2036/1353 vol%×μm), which was not only significantly lower than C (9642/2452 vol%×μm) and F (7713/1489 vol%×μm) (p < 0.05) but also not significantly different from LF (3135/2628 vol%×μm) (p > 0.05). In dentin, only LF (163/227) significantly reduced ∆Z (p < 0.05).

CONCLUSION/CLINICAL RELEVANCE: CO2 laser irradiation did not increase adhesion of S. mutans in vitro. Laser treatment alone protected enamel against biofilm-induced demineralization, while a combined laser-fluoride application was required to protect dentin.}, } @article {pmid27336942, year = {2016}, author = {Gupta, P and Chanda, R and Rai, N and Kataria, VK and Kumar, N}, title = {Antihypertensive, Amlodipine Besilate Inhibits Growth and Biofilm of Human Fungal Pathogen Candida.}, journal = {Assay and drug development technologies}, volume = {14}, number = {5}, pages = {291-297}, doi = {10.1089/adt.2016.714}, pmid = {27336942}, issn = {1557-8127}, abstract = {Candida albicans and Candida glabrata are two important human pathogens associated with high mortality. The anti-Candida potential of an antihypertensive drug, amlodipine besilate (AB), was studied against 10 strains of Candida, including 8 clinical isolates. AB is an inhibitor of voltage-gated Ca[2+] channel (VGCC) of mammals. CCH1 expresses in a part of Ca[2+] channel of Candida, which is a homologue of α subunit of mammalian VGCC. In plate assays, all strains of Candida showed sensitivity to AB on agar media at 256 μg/mL concentration, AB caused lethality at concentrations of 16 and 64 μg/mL in clinical isolates of C. glabrata and all strains of C. albicans, respectively. Minimum fungicidal concentration (MFC) values of AB varied for different strains. The clinical isolates of C. glabrata turned out to be more susceptible to AB than those of C. albicans. At 16 μg/mL, AB showed reduction of biofilm in the range of 41.51%-79.66% for C. glabrata strains and 32.00%-54.06% for C. albicans strains. AB has shown potential antifungal properties against the laboratory strains and clinical isolates of C. glabrata and C. albicans. In conclusion, AB exhibited potential antifungal properties against planktonic form and biofilm of C. glabrata and C. albicans. It was more effective against C. glabrata than against C. albicans in vitro.}, } @article {pmid27336367, year = {2016}, author = {Sampaio, J and Machado, D and Gomes, AM and Machado, I and Santos, C and Lima, N and Carvalho, MJ and Cabrita, A and Rodrigues, A and Martins, M}, title = {Deciphering the Contribution of Biofilm to the Pathogenesis of Peritoneal Dialysis Infections: Characterization and Microbial Behaviour on Dialysis Fluids.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0157870}, pmid = {27336367}, issn = {1932-6203}, mesh = {Adult ; Aged ; Bacterial Load ; *Biofilms ; Biomass ; Catheterization/adverse effects ; Catheters, Indwelling/adverse effects ; Comorbidity ; Dialysis Solutions ; Female ; Humans ; Male ; Middle Aged ; Odds Ratio ; Peritoneal Dialysis/*adverse effects ; Peritonitis/epidemiology/*etiology/*microbiology/mortality ; }, abstract = {Infections are major complications in peritoneal dialysis (PD) with a multifactorial etiology that comprises patient, microbial and dialytic factors. This study aimed at investigating the contribution of microbial biofilms on PD catheters to recalcitrant infections and their interplay with PD related-factors. A prospective observational study was performed on 47 patients attending Centro Hospitalar of Porto and Vila Nova de Gaia/Espinho to whom the catheter was removed due to infectious (n = 16) and non-infectious causes (n = 31). Microbial density on the catheter was assessed by culture methods and the isolated microorganisms identified by matrix-assisted laser desorption/ionization time-of-flight intact cell mass spectrometry. The effect of conventional and three biocompatible PD solutions on 16 Coagulase Negative Staphylococci (CNS) and 10 Pseudomonas aeruginosa strains planktonic growth and biofilm formation was evaluated. Cultures were positive in 87.5% of the catheters removed due infectious and 90.3% removed due to non-infectious causes. However, microbial yields were higher on the cuffs of catheters removed due to infection vs. non-infection. Staphylococci (CNS and Staphylococcus aureus) and P. aeruginosa were the predominant species: 32% and 20% in the infection and 43.3% and 22.7% in the non-infection group, respectively. In general, PD solutions had a detrimental effect on planktonic CNS and P. aeruginosa strains growth. All strains formed biofilms in the presence of PD solutions. The solutions had a more detrimental effect on P. aeruginosa than CNS strains. No major differences were observed between conventional and biocompatible solutions, although in icodextrin solution biofilm biomass was lower than in bicarbonate/lactate solution. Overall, we show that microbial biofilm is universal in PD catheters with the subclinical menace of Staphylococci and P. aeruginosa. Cuffs colonization may significantly contribute to infection. PD solutions differentially impact microbial species. This knowledge is important for the development of infection diagnosis, treatment and preventive strategies.}, } @article {pmid27336224, year = {2016}, author = {Sahoo, PK and Janissen, R and Monteiro, MP and Cavalli, A and Murillo, DM and Merfa, MV and Cesar, CL and Carvalho, HF and de Souza, AA and Bakkers, EP and Cotta, MA}, title = {Nanowire Arrays as Cell Force Sensors To Investigate Adhesin-Enhanced Holdfast of Single Cell Bacteria and Biofilm Stability.}, journal = {Nano letters}, volume = {16}, number = {7}, pages = {4656-4664}, doi = {10.1021/acs.nanolett.6b01998}, pmid = {27336224}, issn = {1530-6992}, mesh = {Adhesins, Bacterial/*chemistry ; *Bacterial Adhesion ; *Biofilms ; *Nanowires ; Xylella/*physiology ; }, abstract = {Surface attachment of a planktonic bacteria, mediated by adhesins and extracellular polymeric substances (EPS), is a crucial step for biofilm formation. Some pathogens can modulate cell adhesiveness, impacting host colonization and virulence. A framework able to quantify cell-surface interaction forces and their dependence on chemical surface composition may unveil adhesiveness control mechanisms as new targets for intervention and disease control. Here we employed InP nanowire arrays to dissect factors involved in the early stage biofilm formation of the phytopathogen Xylella fastidiosa. Ex vivo experiments demonstrate single-cell adhesion forces up to 45 nN, depending on the cell orientation with respect to the surface. Larger adhesion forces occur at the cell poles; secreted EPS layers and filaments provide additional mechanical support. Significant adhesion force enhancements were observed for single cells anchoring a biofilm and particularly on XadA1 adhesin-coated surfaces, evidencing molecular mechanisms developed by bacterial pathogens to create a stronger holdfast to specific host tissues.}, } @article {pmid27333005, year = {2016}, author = {Simion, M and Kim, DM and Pieroni, S and Nevins, M and Cassinelli, C}, title = {Bacterial Biofilm Morphology on a Failing Implant with an Oxidized Surface: A Scanning Electron Microscope Study.}, journal = {The International journal of periodontics & restorative dentistry}, volume = {36}, number = {4}, pages = {485-488}, doi = {10.11607/prd.2804}, pmid = {27333005}, issn = {1945-3388}, mesh = {Adult ; Biofilms ; Dental Implants/*adverse effects ; Dental Restoration Failure ; Gingival Recession/diagnostic imaging/*microbiology/*therapy ; Humans ; Microscopy, Electron, Scanning ; Oxidation-Reduction ; Peri-Implantitis/diagnostic imaging/*microbiology/*therapy ; Surface Properties ; }, abstract = {This case report provided a unique opportunity to investigate the extent of microbiota infiltration on the oxidized implant surface that has been compromised by peri-implantitis. Scanning electron microscopic analysis confirmed the etiologic role of the bacteria on the loss of supporting structure and the difficulty in complete removal of bacterial infiltration on the implant surface. This case report emphasizes the need to perform definitive surface decontamination on failing dental implants prior to a regeneration procedure.}, } @article {pmid27330290, year = {2016}, author = {Li, X and Wong, CH and Ng, TW and Zhang, CF and Leung, KC and Jin, L}, title = {The spherical nanoparticle-encapsulated chlorhexidine enhances anti-biofilm efficiency through an effective releasing mode and close microbial interactions.}, journal = {International journal of nanomedicine}, volume = {11}, number = {}, pages = {2471-2480}, pmid = {27330290}, issn = {1178-2013}, mesh = {Biofilms/*drug effects ; Chlorhexidine/*pharmacology ; *Drug Liberation ; Humans ; Microbial Interactions/*drug effects ; Microscopy, Confocal ; Nanoparticles/*chemistry/ultrastructure ; Particle Size ; Plankton/drug effects/ultrastructure ; Silicon Dioxide/chemistry ; Spectrometry, Fluorescence ; Temperature ; }, abstract = {We reported two forms (sphere and wire) of newly fabricated chlorhexidine (CHX)-loaded mesoporous silica nanoparticles (MSNs), and investigated their releasing capacities and anti-biofilm efficiencies. The interactions of the blank MSNs with planktonic oral microorganisms were assessed by field emission scanning electron microscopy. The anti-biofilm effects of the two forms of nanoparticle-encapsulated CHX were examined by 2,3-bis (2-methoxy- 4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide. The profiles of biofilm penetration were analyzed by fluorescent-labeled MSNs using confocal microscopy and ImageJ. The spherical MSNs with an average diameter of 265 nm exhibited a larger surface area and faster CHX-releasing rate than the MSN wires. The field emission scanning electron microscopy images showed that both shaped MSNs enabled to attach and further fuse with the surfaces of testing microbes. Meanwhile, the nanoparticle-encapsulated CHX could enhance the anti-biofilm efficiency with reference to its free form. Notably, the spherical nanoparticle-encapsulated CHX presented with a greater anti-biofilm capacity than the wire nanoparticle-encapsulated CHX, partly due to their difference in physical property. Furthermore, the relatively even distribution and homogeneous dispersion of spherical MSNs observed in confocal images may account for the enhanced penetration of spherical nanoparticle-encapsulated CHX into the microbial biofilms and resultant anti-biofilm effects. These findings reveal that the spherical nanoparticle-encapsulated CHX could preferably enhance its anti-biofilm efficiency through an effective releasing mode and close interactions with microbes.}, } @article {pmid27330262, year = {2016}, author = {Kali, A and Bhuvaneshwar, D and Charles, PM and Seetha, KS}, title = {Antibacterial synergy of curcumin with antibiotics against biofilm producing clinical bacterial isolates.}, journal = {Journal of basic and clinical pharmacy}, volume = {7}, number = {3}, pages = {93-96}, pmid = {27330262}, issn = {0976-0105}, abstract = {INTRODUCTION: The role of natural bioactive substances in treating infections has been rediscovered as bacterial resistance become common to most of the antibiotics. Curcumin is a bioactive substance from turmeric. Owing to antimicrobial properties, its prospect as an antibacterial agent is currently under focus.

MATERIALS AND METHODS: We have evaluated the in vitro synergy of curcumin with antibiotics against sixty biofilm producing bacterial isolates. Congo red agar method was used to identify the biofilm producing isolates. Curcumin minimum inhibitory concentration (MIC) was determined by agar dilution method. Its antibiotic synergy was identified by the increase in disc diffusion zone size on Mueller-Hinton agar with 32 mg/L curcumin.

RESULTS: The mean MICs of curcumin against Gram-positive and Gram-negative isolates were 126.9 mg/L and 117.4 mg/L, respectively. Maximum synergy was observed with ciprofloxacin among Gram-positive and amikacin, gentamicin, and cefepime among Gram-negative isolates.

CONCLUSIONS: Curcumin per se as well as in combination with other antibiotics has a demonstrable antibacterial action against biofilm producing bacterial isolates. It may have a beneficial role in supplementing antibiotic therapy.}, } @article {pmid27330034, year = {2017}, author = {Ramage, G and Lappin, DF and Millhouse, E and Malcolm, J and Jose, A and Yang, J and Bradshaw, DJ and Pratten, JR and Culshaw, S}, title = {The epithelial cell response to health and disease associated oral biofilm models.}, journal = {Journal of periodontal research}, volume = {52}, number = {3}, pages = {325-333}, pmid = {27330034}, issn = {1600-0765}, mesh = {Aggregatibacter actinomycetemcomitans/metabolism ; *Biofilms/growth & development ; Cell Survival ; Cells, Cultured ; Coculture Techniques ; Cytokines/metabolism ; Epithelial Cells/*microbiology/physiology ; Fusobacterium nucleatum/metabolism ; Gene Expression ; Humans ; In Vitro Techniques ; Mouth/cytology/*microbiology ; Porphyromonas gingivalis/metabolism ; Streptococcus mitis/metabolism ; }, abstract = {BACKGROUND AND OBJECTIVE: Different bacteria differentially stimulate epithelial cells. Biofilm composition and viability are likely to influence the epithelial response. In vitro model systems are commonly used to investigate periodontitis-associated bacteria and their interactions with the host; therefore, understanding factors that influence biofilm-cell interactions is essential. The present study aimed to develop in vitro monospecies and multispecies biofilms and investigate the epithelial response to these biofilms.

MATERIAL AND METHODS: Bacterial biofilms were cultured in vitro and then either live or methanol-fixed biofilms were co-cultured with epithelial cells. Changes in epithelial cell viability, gene expression and cytokine content of culture supernatants were evaluated.

RESULTS: Bacterial viability was better preserved within mixed-species biofilm culture than within single-species biofilm culture. Both mixed- and single-species biofilms stimulated increased expression of mRNA for interleukin 8 (IL8), C-X-C motif chemokine ligand 3 (CXCL3), C-X-C motif chemokine ligand 1 (CXCL1), interleukin 1 (IL1), interleukin 6 (IL6), colony-stimulating factor 2 (CSF2) and tumour necrosis factor (TNF), and the response was greatest in response to mixed-species biofilms. Following co-culture, cytokines detected in the supernatants included IL-8, IL-6, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, with the greatest release of cytokines found following co-culture with methanol-fixed, mixed-species biofilms.

CONCLUSIONS: These data show that epithelial cells generate a distinct cytokine gene- and protein-expression signature in response to live or fixed, single- or multispecies biofilms.}, } @article {pmid27329755, year = {2016}, author = {Richmond, GE and Evans, LP and Anderson, MJ and Wand, ME and Bonney, LC and Ivens, A and Chua, KL and Webber, MA and Sutton, JM and Peterson, ML and Piddock, LJ}, title = {Erratum for Richmond et al., The Acinetobacter baumannii Two-Component System AdeRS Regulates Genes Required for Multidrug Efflux, Biofilm Formation, and Virulence in a Strain-Specific Manner.}, journal = {mBio}, volume = {7}, number = {3}, pages = {}, doi = {10.1128/mBio.00852-16}, pmid = {27329755}, issn = {2150-7511}, support = {G9818340/MRC_/Medical Research Council/United Kingdom ; }, } @article {pmid27328452, year = {2016}, author = {Pourhajibagher, M and Chiniforush, N and Shahabi, S and Ghorbanzadeh, R and Bahador, A}, title = {Sub-lethal doses of photodynamic therapy affect biofilm formation ability and metabolic activity of Enterococcus faecalis.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {15}, number = {}, pages = {159-166}, doi = {10.1016/j.pdpdt.2016.06.003}, pmid = {27328452}, issn = {1873-1597}, mesh = {Biofilms/*drug effects/*growth & development/radiation effects ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Enterococcus faecalis/*drug effects/*metabolism/radiation effects ; Indocyanine Green/administration & dosage ; Light ; Methylene Blue/administration & dosage ; Photochemotherapy/*methods ; Photosensitizing Agents/*administration & dosage ; Root Canal Preparation/methods ; Tolonium Chloride/administration & dosage ; }, abstract = {BACKGROUND: During photodynamic therapy (PDT) in the treatment of a primary endodontic infection, it is extremely likely that microorganisms would be exposed to sub-lethal doses of PDT (sPDT). Although sPDT cannot kill microorganisms, it can considerably influence microbial virulence. This study was conducted to characterize the effect of sPDT using toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) on biofilm formation ability and metabolic activity of Enterococcus faecalis.

METHODS: The antimetabolic and antibiofilm potential of ICG-, TBO-, and MB-sPDT against E. faecalis was analyzed at sub-lethal doses (1/2-1/64 minimum inhibitory concentration) using the XTT reduction assay, crystal violet assay, and scanning electron microscopy.

RESULTS: Higher doses of sPDT adversely affected biofilm formation ability and metabolic activity. ICG-, TBO-, and MB-PDT at a maximum sub-lethal dose markedly reduced the formation of biofilm up to 42.8%, 22.6%, and 19.5%, respectively. ICG-, TBO-, and MB-sPDT showed a marked reduction in bacterial metabolic activity by 98%, 94%, and 82%, respectively. ICG-PDT showed a stronger inhibitory effect on biofilm formation in E. faecalis than MB- and TBO-PDT at sub-lethal levels. Interestingly, a gradual increase in metabolic activity and biofilm formation upon exposure to a lower dose of test sPDT were observed.

CONCLUSION: sPDT showed dual effect on biofilm formation ability and metabolic activity of E. faecalis. High doses revealed antimetabolic and antibiofilm potential activity, whereas lower doses had conflicting results. Hence, when PDT is prescribed in clinical settings, the dose of PDT used in vivo should be taken into consideration.}, } @article {pmid27327953, year = {2017}, author = {Orrego, S and Melo, MA and Lee, SH and Xu, HHK and Arola, DD}, title = {Fatigue of human dentin by cyclic loading and during oral biofilm challenge.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {105}, number = {7}, pages = {1978-1985}, doi = {10.1002/jbm.b.33729}, pmid = {27327953}, issn = {1552-4981}, support = {R01 DE016904/DE/NIDCR NIH HHS/United States ; R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {Adolescent ; Adult ; Biofilms/*growth & development ; *Dental Caries ; Dentin/*chemistry/microbiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Male ; *Stress, Mechanical ; }, abstract = {Fatigue caused by the cyclic loads of mastication and acid attack caused by the excretion of oral biofilms are two of the most critical challenges to the success of dental restorations and their clinical service life. The objective of this investigation was to evaluate the fatigue strength of human dentin when exposed to a simultaneous challenge of cyclic loading and acidic attack from oral bacteria. Rectangular beams of coronal dentin were obtained from third molars and subjected to cyclic flexural loading while exposed to an in-vitro microcosm biofilm model. Two different cariogenic protocols were considered and results were compared with those for control samples evaluated at neutral pH. According to the fatigue life distributions, dentin exposed to the biofilm model with 2.0% sucrose supplements pulsed twice per day caused a significant reduction in the fatigue strength (p < 0.001) with respect to 0.2% sucrose supplements pulsed once a day, and the control environment (without biofilm). The endurance limit after biofilm exposure was 20 MPa, which is 60% lower than that of the control environment without biofilm (50 MPa). Biofilm attack of dentin increases the likelihood of restored tooth failures by fatigue and after only modest periods of exposure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1978-1985, 2017.}, } @article {pmid27327765, year = {2016}, author = {Taglialegna, A and Navarro, S and Ventura, S and Garnett, JA and Matthews, S and Penades, JR and Lasa, I and Valle, J}, title = {Staphylococcal Bap Proteins Build Amyloid Scaffold Biofilm Matrices in Response to Environmental Signals.}, journal = {PLoS pathogens}, volume = {12}, number = {6}, pages = {e1005711}, pmid = {27327765}, issn = {1553-7374}, support = {100280/WT_/Wellcome Trust/United Kingdom ; 104933/WT_/Wellcome Trust/United Kingdom ; G1001664/MRC_/Medical Research Council/United Kingdom ; MR/J006874/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Amyloidogenic Proteins/*metabolism ; Animals ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Disease Models, Animal ; Immunoblotting ; Mice ; Microscopy, Fluorescence ; Polymerase Chain Reaction ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/metabolism ; }, abstract = {Biofilms are communities of bacteria that grow encased in an extracellular matrix that often contains proteins. The spatial organization and the molecular interactions between matrix scaffold proteins remain in most cases largely unknown. Here, we report that Bap protein of Staphylococcus aureus self-assembles into functional amyloid aggregates to build the biofilm matrix in response to environmental conditions. Specifically, Bap is processed and fragments containing at least the N-terminus of the protein become aggregation-prone and self-assemble into amyloid-like structures under acidic pHs and low concentrations of calcium. The molten globule-like state of Bap fragments is stabilized upon binding of the cation, hindering its self-assembly into amyloid fibers. These findings define a dual function for Bap, first as a sensor and then as a scaffold protein to promote biofilm development under specific environmental conditions. Since the pH-driven multicellular behavior mediated by Bap occurs in coagulase-negative staphylococci and many other bacteria exploit Bap-like proteins to build a biofilm matrix, the mechanism of amyloid-like aggregation described here may be widespread among pathogenic bacteria.}, } @article {pmid27327408, year = {2016}, author = {Jia, Z and Shi, Y and Xiong, P and Zhou, W and Cheng, Y and Zheng, Y and Xi, T and Wei, S}, title = {From Solution to Biointerface: Graphene Self-Assemblies of Varying Lateral Sizes and Surface Properties for Biofilm Control and Osteodifferentiation.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {27}, pages = {17151-17165}, doi = {10.1021/acsami.6b05198}, pmid = {27327408}, issn = {1944-8252}, mesh = {Animals ; Biofilms ; Cell Differentiation ; Cell Line ; Graphite/*chemistry ; Mice ; Oxides ; Staphylococcus aureus ; Surface Properties ; }, abstract = {Bringing multifunctional graphene out of solution through facile self-assembly to form 2D surface nanostructures, with control over the lateral size and surface properties, would be an intriguing accomplishment, especially in biomedical fields where biointerfaces with functional diversity are in high demand. Guided by this goal, in this work, we built such graphene-based self-assemblies on orthopedic titanium, attempting to selectively regulate bacterial activities and osteoblastic functions, which are both crucial in bone regeneration. Briefly, large-area graphene oxide (GO) sheets and functionalized reduced GO (rGO) micro-/nanosheets were self-assembled spontaneously and controllably onto solid Ti, through an evaporation-assisted electrostatic assembly process and a mussel-inspired one-pot assembly process, respectively. The resultant layers were characterized in terms of topological structure, chemical composition, hydrophilicity, and protein adsorption properties. The antibacterial efficacies of the assemblies were examined by challenging them with pathogenic Staphylococcus aureus (S. aureus) bacteria that produce biofilms, whereby around 50% antiadhesion effects and considerable antibiofilm activities were observed for both layer types but through dissimilar modes of action. Their cytocompatibility and osteogenic potential were also investigated. Interfaced with MC3T3-E1 cells, the functionalized rGO sheets evoked better cell adhesion and growth than GO sheets, whereas the latter elicited higher osteodifferentiation activity throughout a 28-day in vitro culture. In this work, we showed that it is technically possible to construct graphene interface layers of varying lateral dimensions and surface properties and confirmed the concept of using the obtained assemblies to address the two major challenges facing orthopedic clinics. In addition, we determined fundamental implications for understanding the surface-biology relationship of graphene biomaterials, in efforts to better design and more safely use them for future biomedicine.}, } @article {pmid27327215, year = {2016}, author = {Phan, H and Yates, MD and Kirchhofer, ND and Bazan, GC and Tender, LM and Nguyen, TQ}, title = {Biofilm as a redox conductor: a systematic study of the moisture and temperature dependence of its electrical properties.}, journal = {Physical chemistry chemical physics : PCCP}, volume = {18}, number = {27}, pages = {17815-17821}, doi = {10.1039/c6cp03583c}, pmid = {27327215}, issn = {1463-9084}, mesh = {Bioelectric Energy Sources/*standards ; *Biofilms ; Electric Conductivity ; Electron Transport ; Geobacter/*chemistry/metabolism ; Oxidation-Reduction ; Temperature ; }, abstract = {Some microbial biofilms are electrically conductive. However, the mechanism of electron transport remains unclear. Here, we show that μm-scale long-distance electron transport through electrode-grown Geobacter sulfurreducens biofilms occurs via redox conduction, as determined by electrical measurements performed under varied hydration states and temperatures.}, } @article {pmid27326455, year = {2016}, author = {Mashima, I and Theodorea, CF and Thaweboon, B and Thaweboon, S and Nakazawa, F}, title = {Identification of Veillonella Species in the Tongue Biofilm by Using a Novel One-Step Polymerase Chain Reaction Method.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0157516}, pmid = {27326455}, issn = {1932-6203}, mesh = {Adolescent ; Biofilms/*growth & development ; Child ; Clone Cells ; DNA Primers/metabolism ; DNA-Directed RNA Polymerases/metabolism ; Female ; Humans ; Male ; Mouth/microbiology ; Phylogeny ; Polymerase Chain Reaction/*methods ; Species Specificity ; Tongue/*microbiology ; Veillonella/genetics/*isolation & purification ; }, abstract = {Six Veillonella species have been frequently isolated from human oral cavities including infectious sites. Recently, it was reported that diet, smoking, and possibly socioeconomic status can influence the bacterial profile in oral cavities. In addition, oral hygiene habits may also influence oral microbiota in terms of both numbers and diversity of microorganisms. In this study, the identification of Veillonella species in tongue biofilms of Thai children, divided into three groups dependent on their status of oral hygiene. For this, we used a novel one-step PCR method with species-specific primer sets based on sequences of the rpoB gene. As shown in the results, the number of isolates of Veillonella species was 101 strains from only 10 of 89 subjects. However, the total number of bacteria was high for all subjects. Since it was reported in previous studies that Veillonella species were easy to isolate in human tongue biofilms at high numbers, the results obtained in this study may suggest country- or age-specific differences. Moreover, Veillonella species were detected predominantly in subjects who had poor oral hygiene compared to those with good or moderate oral hygiene. From these results, there is a possibility that Veillonella species may be an index of oral hygiene status. Furthermore, V. rogosae was a predominant species in tongue biofilms of Thai children, whereas V. parvula and V. denticariosi were not isolated at all. These characteristics of the distribution and frequency of Veillonella species are similar to those reported in previous studies. Although further studies are needed in other countries, in this study, a successful novel one-step PCR method was established to detect Veillonella species in human oral cavities easily and effectively. Furthermore, this is the first report investigating the distribution and frequency of Veillonella species in tongue biofilms of Thai children.}, } @article {pmid27325010, year = {2016}, author = {Shen, Y and Zhao, J and de la Fuente-Núñez, C and Wang, Z and Hancock, RE and Roberts, CR and Ma, J and Li, J and Haapasalo, M and Wang, Q}, title = {Experimental and Theoretical Investigation of Multispecies Oral Biofilm Resistance to Chlorhexidine Treatment.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27537}, pmid = {27325010}, issn = {2045-2322}, support = {R01 GM078994/GM/NIGMS NIH HHS/United States ; R33 AI098701/AI/NIAID NIH HHS/United States ; 2R01GM078994-05A1/GM/NIGMS NIH HHS/United States ; //Canadian Institutes of Health Research/Canada ; }, mesh = {Anti-Bacterial Agents/*administration & dosage/chemistry ; Biofilms/*drug effects/growth & development ; Chlorhexidine/administration & dosage/*analogs & derivatives/chemistry ; Humans ; Microbial Viability/drug effects ; Microscopy, Confocal ; Mouth Diseases/*drug therapy/microbiology ; Quorum Sensing/drug effects ; Surface Properties ; }, abstract = {We investigate recovery of multispecies oral biofilms following chlorhexidine gluconate (CHX) and CHX with surface modifiers (CHX-Plus) treatment. Specifically, we examine the percentage of viable bacteria in the biofilms following their exposure to CHX and CHX-Plus for 1, 3, and 10 minutes, respectively. Before antimicrobial treatment, the biofilms are allowed to grow for three weeks. We find that (a). CHX-Plus kills bacteria in biofilms more effectively than the regular 2% CHX does, (b). cell continues to be killed for up to one week after exposure to the CHX solutions, (c). the biofilms start to recover after two weeks, the percentage of the viable bacteria recovers in the 1 and 3 minutes treatment groups but not in the 10 minutes treatment group after five weeks, and the biofilms fully return to the pretreatment levels after eight weeks. To understand the mechanism, a mathematical model for multiple bacterial phenotypes is developed, adopting the notion that bacterial persisters exist in the biofilms together with regulatory quorum sensing molecules and growth factor proteins. The model reveals the crucial role played by the persisters, quorum sensing molecules, and growth factors in biofilm recovery, accurately predicting the viable bacterial population after CHX treatment.}, } @article {pmid27324342, year = {2016}, author = {Xu, Z and Liang, Y and Lin, S and Chen, D and Li, B and Li, L and Deng, Y}, title = {Crystal Violet and XTT Assays on Staphylococcus aureus Biofilm Quantification.}, journal = {Current microbiology}, volume = {73}, number = {4}, pages = {474-482}, pmid = {27324342}, issn = {1432-0991}, mesh = {*Biofilms ; Gentian Violet/chemistry ; Humans ; Staining and Labeling/*methods ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*chemistry/genetics/isolation & purification/physiology ; Tetrazolium Salts/chemistry ; }, abstract = {Staphylococcus aureus (S. Aureus) is a common food-borne pathogenic microorganism. Biofilm formation remains the major obstruction for bacterial elimination. The study aims at providing a basis for determining S. aureus biofilm formation. 257 clinical samples of S. aureus isolates were identified by routine analysis and multiplex PCR detection and found to contain 227 MRSA, 16 MSSA, 11 MRCNS, and 3 MSCNS strains. Two assays for quantification of S. aureus biofilm formation, the crystal violet (CV) assay and the XTT (tetrazolium salt reduction) assay, were optimized, evaluated, and further compared. In CV assay, most isolates formed weak biofilm 74.3 %), while the rest formed moderate biofilm (23.3 %) or strong biofilm (2.3 %). However, most isolates in XTT assay showed weak metabolic activity (77.0 %), while the rest showed moderate metabolic activity (17.9 %) or high metabolic activity (5.1 %). In this study, we found a distinct strain-to-strain dissimilarity in terms of both biomass formation and metabolic activity, and it was concluded from this study that two assays were mutual complementation rather than being comparison.}, } @article {pmid27323358, year = {2017}, author = {Francis, NC and Yao, W and Grundfest, WS and Taylor, ZD}, title = {Laser-Generated Shockwaves as a Treatment to Reduce Bacterial Load and Disrupt Biofilm.}, journal = {IEEE transactions on bio-medical engineering}, volume = {64}, number = {4}, pages = {882-889}, pmid = {27323358}, issn = {1558-2531}, support = {R01 CA220663/CA/NCI NIH HHS/United States ; UL1 TR000124/TR/NCATS NIH HHS/United States ; }, mesh = {Animals ; Bacterial Load/physiology/*radiation effects ; Biofilms/growth & development/*radiation effects ; Disinfection/*methods ; Dose-Response Relationship, Radiation ; *High-Energy Shock Waves ; In Vitro Techniques ; Lasers ; Radiation Dosage ; Skin/*microbiology/*radiation effects ; Swine ; }, abstract = {OBJECTIVE: The goal of this paper is to demonstrate and evaluate the potential efficacy of laser-generated shockwave (LGS) therapy on biofilm infected tissue.

METHODS: To demonstrate proof of concept, Staphylococcus epidermidis was allowed to proliferate on ex vivo pigskin, until mature biofilm formation was achieved, and then subjected to LGS. Bacterial load between control and treated samples was compared using the swab technique and colony counting. Scanning electron microscopy (SEM) was then used to visualize the biofilm growth and resulting reduction in biofilm coverage from treatment. Images were false colored to improve contrast of biofilm, and percent biofilm coverage was computed, along with biofilm cluster size.

RESULTS: LGS reduced bacterial load by 69% (p = 0.008). Imaging showed biofilm coverage reduced by 52% and significantly reduced average cluster size (p 0.001).

CONCLUSION: LGS therapy reduced the burden of bacterial biofilm on ex vivo pigskin and can be visualized using SEM imaging.

SIGNIFICANCE: LGS therapy is a new treatment for infected wounds, allowing rapid disruption of biofilm to 1) remove bacteria and 2) increase susceptibility of remaining biofilm to topical antibiotics. This can lead to improved wound healing times, reduced patient morbidity, and decreased healthcare costs.}, } @article {pmid27323145, year = {2016}, author = {Wang, LY and Ma, LN and Liu, YS}, title = {Effects of nucleotide usage on the synonymous codon usage patterns of biofilm-associated genes in Haemophilus parasuis.}, journal = {Genetics and molecular research : GMR}, volume = {15}, number = {2}, pages = {}, doi = {10.4238/gmr.15027226}, pmid = {27323145}, issn = {1676-5680}, mesh = {Biofilms/growth & development ; Codon/*genetics ; *Evolution, Molecular ; *Genetic Variation ; Haemophilus parasuis/*genetics ; Mutation ; Nucleotides/genetics ; Silent Mutation/genetics ; }, abstract = {To provide a new perspective on the evolutionary characteristics shaping the genetic diversity of Haemophilus parasuis biofilms, the relative synonymous codon usage values, codon usage bias values, effective number of codons (ENC) values, codon adaptation index (CAI) values, and the base components were calculated. Our objective was to implement a comparative analysis to evaluate the dynamic evolution of biofilm-associated genes in H. parasuis. The analysis of genetic diversity provides evidence that some biofilm-associated genes have similar genetic features. However, other genes show some variations in genetic direction. Furthermore, preferential selection of the synonymous codons and amino acids is apparent in biofilm-associated genes. Additionally, the ENC and CAI data from this study all strongly suggested that biofilm-associated genes may depend on deoptimization to adapt to environmental changes, and the mutation effect of biofilm-associated genes in H. parasuis plays an important role in shaping the genetic features. Our results reveal that the mutations of biofilm-associated genes form a set of sophisticated strategies for combating the environmental changes arising from the host cell in the evolution of H. parasuis.}, } @article {pmid27321770, year = {2016}, author = {Ahmed, A and Khan, AK and Anwar, A and Ali, SA and Shah, MR}, title = {Biofilm inhibitory effect of chlorhexidine conjugated gold nanoparticles against Klebsiella pneumoniae.}, journal = {Microbial pathogenesis}, volume = {98}, number = {}, pages = {50-56}, doi = {10.1016/j.micpath.2016.06.016}, pmid = {27321770}, issn = {1096-1208}, mesh = {Biofilms/*drug effects ; Chlorhexidine/chemistry/*pharmacology ; Disinfectants/chemistry/*pharmacology ; Formazans/analysis ; Gentian Violet/analysis ; Gold/chemistry/*pharmacology ; Klebsiella pneumoniae/*drug effects/physiology ; Microscopy, Atomic Force ; Microscopy, Fluorescence ; Nanoparticles/chemistry/*microbiology/ultrastructure ; Spectrometry, Mass, Electrospray Ionization ; Spectrophotometry ; Spectroscopy, Fourier Transform Infrared ; Staining and Labeling ; Surface Plasmon Resonance ; Tetrazolium Salts/analysis ; }, abstract = {Klebsiella pneumoniae (K. pneumoniae) is one of the major pathogen associated with nosocomial infections, especially catheter associated urinary tract infections which involved biofilm formation. This study was designed to evaluate the antibiofilm efficacy of gold nanoparticle conjugated with chlorhexidine (Au-CHX) against K. pneumoniae isolates. Au-CHX was synthesized and analyzed for stability by using UV-Visible spectrophotometry, atomic force microscopy (AFM), fourier transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectroscopy (ESI-MS). Biofilm inhibition and eradication was performed by crystal violet, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and further confirmed by florescence and AFM microscopy. Au-CHX showed the maxima surface plasmon resonance (SPR) band at 535 nm, spherical morphology and polydispersity with size in the range of 20-100 nm. The micro molar concentrations (i.e. 25 and 100 μM) of Au-CHX completely inhibited the biofilm formation and metabolic activity within biofilms of K. pneumoniae reference and three tested clinical isolates, respectively. Time dependant biofilm inhibition assay showed that Au-CHX inhibited the early stage of biofilm formation. While at 75 and 100 μM concentrations, it also eradicated the established biofilms of K. pneumoniae isolates as compared to 2 mM chlorhexidine. Reduced florescence signals and surface roughness during microscopic analysis further confirms the antibiofilm activity of Au-CHX against K. pneumoniae ATCC13882 and clinical isolates. Thus it is concluded that chlorhexidine coated gold nanoparticle not only inhibits the biofilm formation of K. pneumoniae ATCC and clinical isolates but also eradicated the preformed biofilm.}, } @article {pmid27321674, year = {2016}, author = {Vargas, D and Hageman, S and Gulati, M and Nobile, CJ and Rawat, M}, title = {S-nitrosomycothiol reductase and mycothiol are required for survival under aldehyde stress and biofilm formation in Mycobacterium smegmatis.}, journal = {IUBMB life}, volume = {68}, number = {8}, pages = {621-628}, pmid = {27321674}, issn = {1521-6551}, support = {R00 AI100896/AI/NIAID NIH HHS/United States ; SC3 GM100855/GM/NIGMS NIH HHS/United States ; }, mesh = {Aldehyde Oxidoreductases/*genetics/metabolism ; Aldehydes/metabolism ; Biofilms/*drug effects ; Cysteine/metabolism ; Cysteine Synthase/*genetics/metabolism ; Glycopeptides/metabolism ; Inositol/metabolism ; Mycobacterium Infections, Nontuberculous/drug therapy/*microbiology ; Mycobacterium smegmatis/drug effects/pathogenicity ; S-Nitrosothiols/metabolism ; }, abstract = {We show that Mycobacterium smegmatis mutants disrupted in mscR, coding for a dual function S-nitrosomycothiol reductase and formaldehyde dehydrogenase, and mshC, coding for a mycothiol ligase and lacking mycothiol (MSH), are more susceptible to S-nitrosoglutathione (GSNO) and aldehydes than wild type. MSH is a cofactor for MscR, and both mshC and mscR are induced by GSNO and aldehydes. We also show that a mutant disrupted in egtA, coding for a γ-glutamyl cysteine synthetase and lacking in ergothioneine, is sensitive to nitrosative stress but not to aldehydes. In addition, we find that MSH and S-nitrosomycothiol reductase are required for normal biofilm formation in M. smegmatis, suggesting potential new therapeutic pathways to target to inhibit or disrupt biofilm formation. © 2016 IUBMB Life, 68(8):621-628, 2016.}, } @article {pmid27319816, year = {2016}, author = {Kaatz Wahlen, L and Parker, A and Walker, D and Pasmore, M and Sturman, P}, title = {Predictive modeling for hot water inactivation of planktonic and biofilm-associated Sphingomonas parapaucimobilis to support hot water sanitization programs.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {751-761}, doi = {10.1080/08927014.2016.1192155}, pmid = {27319816}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Colony Count, Microbial ; *Hot Temperature ; Kinetics ; *Models, Biological ; Models, Statistical ; Plankton/*physiology ; *Sanitation ; Sphingomonas/*physiology ; Water/*chemistry ; }, abstract = {Hot water sanitization is a common means to maintain microbial control in process equipment for industries where microorganisms can degrade product or cause safety issues. This study compared the hot water inactivation kinetics of planktonic and biofilm-associated Sphingomonas parapaucimobilis at temperatures relevant to sanitization processes used in the pharmaceutical industry, viz. 65, 70, 75, and 80°C. Biofilms exhibited greater resistance to hot water than the planktonic cells. Both linear and nonlinear statistical models were developed to predict the log reduction as a function of temperature and time. Nonlinear Michaelis-Menten modeling provided the best fit for the inactivation data. Using the model, predictions were calculated to determine the times at which specific log reductions are achieved. While ≥80°C is the most commonly cited temperature for hot water sanitization, the predictive modeling suggests that temperatures ≥75°C are also effective at inactivating planktonic and biofilm bacteria in timeframes appropriate for the pharmaceutical industry.}, } @article {pmid27318453, year = {2016}, author = {Salli, KM and Forssten, SD and Lahtinen, SJ and Ouwehand, AC}, title = {Influence of sucrose and xylitol on an early Streptococcus mutans biofilm in a dental simulator.}, journal = {Archives of oral biology}, volume = {70}, number = {}, pages = {39-46}, doi = {10.1016/j.archoralbio.2016.05.020}, pmid = {27318453}, issn = {1879-1506}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Dental Caries/microbiology ; Dental Plaque ; Microbial Viability/drug effects ; Mouth/microbiology ; Real-Time Polymerase Chain Reaction ; Saliva, Artificial/chemistry ; Streptococcus mutans/*drug effects/genetics/physiology ; Streptococcus sobrinus/drug effects/genetics ; Sucrose/*pharmacology ; Surface Properties ; Sweetening Agents/pharmacology ; Xylitol/*pharmacology ; }, abstract = {OBJECTIVES: In vitro methods to study dental biofilms are useful in finding ways to support a healthy microbial balance in the oral cavity. The effects of sucrose, xylitol, and their combination on three strains of Streptococcus mutans and one strain of Streptococcus sobrinus were studied using a dental simulator.

METHODS: A simulator was used to mimic the oral cavity environment. It provided a continuous-flow system using artificial saliva (AS), constant temperature, mixing, and hydroxyapatite (HA) surface in which the influence of xylitol was studied. The quantities of planktonic and adhered bacteria were measured by real-time qPCR.

RESULTS: Compared against the untreated AS, adding 1% sucrose increased the bacterial colonization of HA (p<0.0001) whereas 2% xylitol decreased it (p<0.05), with the exception of clinical S. mutans isolate 117. The combination of xylitol and sucrose decreased the bacterial quantities within the AS and the colonization on the HA by clinical S. mutans isolate 2366 was reduced (p<0.05). Increasing the concentration (2%-5%) of xylitol caused a reduction in bacterial counts even in the presence of sucrose.

CONCLUSIONS: The continuous-culture biofilm model showed that within a young biofilm, sucrose significantly promotes whereas xylitol reduces bacterial colonization and proliferation. The results indicate that xylitol affects the ability of certain S. mutans strains to adhere to the HA. Clinical studies have also shown that xylitol consumption decreases caries incidence and reduces the amount of plaque. This study contributes to the understanding of the mechanism behind these clinical observations.}, } @article {pmid27318448, year = {2016}, author = {Derlon, N and Grütter, A and Brandenberger, F and Sutter, A and Kuhlicke, U and Neu, TR and Morgenroth, E}, title = {The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance.}, journal = {Water research}, volume = {102}, number = {}, pages = {63-72}, doi = {10.1016/j.watres.2016.06.019}, pmid = {27318448}, issn = {1879-2448}, mesh = {*Biofilms ; Filtration ; Membranes, Artificial ; Pressure ; *Ultrafiltration ; }, abstract = {This study aimed at identifying how to improve the level of permeate flux stabilisation during gravity-driven membrane filtration without control of biofilm formation. The focus was therefore on understanding (i) how the different fractions of the biofilms (inorganics particles, bacterial cells, EPS matrix) influence its hydraulic resistance and (ii) how the compression of biofilms impacts its hydraulic resistance, i.e., can water head be increased to increase the level of permeate flux stabilisation. Biofilms were developed on ultrafiltration membranes at 88 and 284 cm water heads with dead-end filtration for around 50 days. A larger water head resulted in a smaller biofilm permeability (150 and 50 L m(-2) h(-1) bar(-1) for biofilms grown at 88 cm and 284 cm water head, respectively). Biofilms were mainly composed of EPS (>90% in volume). The comparison of the hydraulic resistances of biofilms to model fouling layers indicated that most of the hydraulic resistance is due to the EPS matrix. The compressibility of the biofilm was also evaluated by subjecting the biofilms to short-term (few minutes) and long-term variations of transmembrane pressures (TMP). A sudden change of TMP resulted in an instantaneous and reversible change of biofilm hydraulic resistance. A long-term change of TMP induced a slow change in the biofilm hydraulic resistance. Our results demonstrate that the response of biofilms to a TMP change has two components: an immediate variation of resistance (due to compression/relaxation) and a long-term response (linked to biofilm adaptation/growth). Our results provide relevant information about the relationship between the operating conditions in terms of TMP, the biofilm structure and composition and the resulting biofilm hydraulic resistance. These findings have practical implications for a broad range of membrane systems.}, } @article {pmid27317856, year = {2016}, author = {Ben Taheur, F and Kouidhi, B and Fdhila, K and Elabed, H and Ben Slama, R and Mahdouani, K and Bakhrouf, A and Chaieb, K}, title = {Anti-bacterial and anti-biofilm activity of probiotic bacteria against oral pathogens.}, journal = {Microbial pathogenesis}, volume = {97}, number = {}, pages = {213-220}, doi = {10.1016/j.micpath.2016.06.018}, pmid = {27317856}, issn = {1096-1208}, mesh = {*Antibiosis ; Bacillus cereus/*growth & development/physiology ; Biofilms/*growth & development ; Food Microbiology ; Hordeum/microbiology ; Lactobacillales/growth & development/isolation & purification/*physiology ; Microbial Sensitivity Tests ; Mouth/*microbiology ; *Probiotics ; Streptococcus salivarius/*growth & development/physiology ; }, abstract = {In this study, three lactic acid bacteria (LAB), isolated from barley, traditional dried meat and fermented olive were characterized and tested for their anti-bacterial and anti-biofilm activities against oral bacteria. Our results revealed that the tested LAB were γ-hemolytic and were susceptible to four antibiotics. All the strains were resistant to low pH, bile salt, pepsin and pancreatin. Furthermore, FB2 displayed a high aut-oaggregative phenotype (99.54%) while FF2 exhibited the best co-aggregation rate. Concerning the microbial adhesion to solvent, FB2 was the most hydrophobic strain (data obtained with chloroform and n-hexadecane). In addition Pediococcus pentosaceus FB2 and Lactobacillus brevis FF2 displayed a significant inhibitory effect against Streptococcus salivarius B468 (MIC = 10%). Moreover the selected strains were able to inhibit biofilm formation of Bacillus cereus ATCC14579 (MBIC50 = 28.16%) and S. salivarius B468 (MBIC50 = 42.28%). The selected LAB could be considered as candidate probiotics for further application in functional food and mainly in the prevention of oral diseases.}, } @article {pmid27316964, year = {2016}, author = {Zhang, T and Bae, D and Wang, C}, title = {Listeria monocytogenes DNA Glycosylase AdlP Affects Flagellar Motility, Biofilm Formation, Virulence, and Stress Responses.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {17}, pages = {5144-5152}, pmid = {27316964}, issn = {1098-5336}, mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; DNA Glycosylases/genetics/*metabolism ; Female ; Flagella/genetics/*physiology ; Gene Expression Regulation, Bacterial ; Humans ; Hydrogen Peroxide/pharmacology ; Listeria monocytogenes/drug effects/*enzymology/*pathogenicity/physiology ; Listeriosis/*microbiology ; Mice ; Mice, Inbred BALB C ; Stress, Physiological ; Virulence ; }, abstract = {UNLABELLED: The temperature-dependent alteration of flagellar motility gene expression is critical for the foodborne pathogen Listeria monocytogenes to respond to a changing environment. In this study, a genetic determinant, L. monocytogenes f2365_0220 (lmof2365_0220), encoding a putative protein that is structurally similar to the Bacillus cereus alkyl base DNA glycosylase (AlkD), was identified. This determinant was involved in the transcriptional repression of flagellar motility genes and was named adlP (encoding an AlkD-like protein [AdlP]). Deletion of adlP activated the expression of flagellar motility genes at 37°C and disrupted the temperature-dependent inhibition of L. monocytogenes motility. The adlP null strains demonstrated decreased survival in murine macrophage-like RAW264.7 cells and less virulence in mice. Furthermore, the deletion of adlP significantly decreased biofilm formation and impaired the survival of bacteria under several stress conditions, including the presence of a DNA alkylation compound (methyl methanesulfonate), an oxidative agent (H2O2), and aminoglycoside antibiotics. Our findings strongly suggest that adlP may encode a bifunctional protein that transcriptionally represses the expression of flagellar motility genes and influences stress responses through its DNA glycosylase activity.

IMPORTANCE: We discovered a novel protein that we named AlkD-like protein (AdlP). This protein affected flagellar motility, biofilm formation, and virulence. Our data suggest that AdlP may be a bifunctional protein that represses flagellar motility genes and influences stress responses through its DNA glycosylase activity.}, } @article {pmid27316688, year = {2016}, author = {Tasse, J and Croisier, D and Badel-Berchoux, S and Chavanet, P and Bernardi, T and Provot, C and Laurent, F}, title = {Preliminary results of a new antibiotic susceptibility test against biofilm installation in device-associated infections: the Antibiofilmogram®.}, journal = {Pathogens and disease}, volume = {74}, number = {6}, pages = {}, doi = {10.1093/femspd/ftw057}, pmid = {27316688}, issn = {2049-632X}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Arthritis, Infectious/diagnosis/microbiology ; Biofilms/*drug effects ; Bone Diseases, Infectious/diagnosis/microbiology ; Catheter-Related Infections/microbiology ; Disease Models, Animal ; Female ; Humans ; Mice ; *Microbial Sensitivity Tests/methods ; Prosthesis-Related Infections/*microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects ; }, abstract = {Biofilms are complex communities of microorganisms embedded in an extracellular matrix and adherent to a surface. The development was described as a four-stage process leading to the formation of a mature biofilm which was resistant to immune system and antibiotic actions. In bone and joint infections (BJIs), the formation of biofilms is a leading cause of treatment failure. Here we study the capacity of 11 antibiotics commonly used in the treatment of BJIs to inhibit the biofilm formation on 29 clinical Staphylococcus aureus isolates by a new test called Antibiofilmogram(®) The minimal inhibitory concentration (MIC) and biofilm MIC (bMIC) were determined in vitro and showed similar values for clindamycin, fusidic acid, linezolid and rifampin. Reversely, daptomycin, fosfomycin, gentamicin and ofloxacin showed a bMIC distribution different from MIC with bMIC above breakpoint. Finally, cloxacillin, teicoplanin and vancomycin revealed an intermediate bMIC distribution with a strain-dependent pattern. A murine in vivo model of catheter-associated S. aureus infection was made and showed a significant reduction, but not total prevention, of catheter colonization with cloxacillin at bMIC, and no or limited reduction with cloxacillin at MIC. Antibiofilmogram(®) could be of great interest after surgical operations on contaminated prostheses and after bacteremia in order to prevent the colonization of the device.}, } @article {pmid27316318, year = {2016}, author = {Gao, Y and Jiang, X and Lin, D and Chen, Y and Tong, Z}, title = {The Starvation Resistance and Biofilm Formation of Enterococcus faecalis in Coexistence with Candida albicans, Streptococcus gordonii, Actinomyces viscosus, or Lactobacillus acidophilus.}, journal = {Journal of endodontics}, volume = {42}, number = {8}, pages = {1233-1238}, doi = {10.1016/j.joen.2016.05.002}, pmid = {27316318}, issn = {1878-3554}, mesh = {Actinomyces viscosus/*growth & development ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacteriological Techniques ; Biofilms/*growth & development ; Candida albicans/*growth & development ; Cattle ; Colony Count, Microbial ; Dental Pulp Cavity/*microbiology ; Enterococcus faecalis/*growth & development ; Lactobacillus acidophilus/*growth & development ; Microbial Consortia ; Microbial Viability ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Streptococcus gordonii/*growth & development ; }, abstract = {INTRODUCTION: Enterococcus faecalis is the most frequently detected species in root canal-treated teeth, and it is able to survive under starvation conditions. However, persistent periapical disease is often caused by multispecies. The aim of this study was to explore the survival of E. faecalis in starvation conditions and biofilm formation with the 4 common pathogenic species.

METHODS: A dual-species model of Candida albicans, Streptococcus gordonii, Actinomyces viscosus, or Lactobacillus acidophilus in combination with E. faecalis was established and allowed to grow in phosphate-buffered saline for the examination of starvation survival. Cefuroxime sodium and vancomycin at a concentration of 100 mg/L were added into brain-heart infusion plate agar to count the 2 bacteria separately in the dual species. Scanning electron microscopy was used to observe the dual species and multiple species on the root canal dentin of bovine teeth for 48 hours. A confocal laser scanning microscope was used to show the 4 groups of dual-species biofilms on substrates with glass bottoms for 48 hours.

RESULTS: E. faecalis was more resistant to starvation in coexistence with C. albicans, S. gordonii, A. viscosus, or L. acidophilus, and S. gordonii was completely inhibited in coexistence with E. faecalis. The dual-species biofilm showed that E. faecalis formed thicker and denser biofilms on the root canal dentin and glass slides in coexistence with S. gordonii and A. viscosus than C. albicans and L. acidophilus.

CONCLUSIONS: The multispecies community is conducive to the resistance to starvation of E. faecalis and biofilm formation in root canals.}, } @article {pmid27314764, year = {2016}, author = {Li, WL and Zhao, XC and Zhao, ZW and Huang, YJ and Zhu, XZ and Meng, RZ and Shi, C and Yu, L and Guo, N}, title = {In vitro antimicrobial activity of honokiol against Staphylococcus aureus in biofilm mode.}, journal = {Journal of Asian natural products research}, volume = {18}, number = {12}, pages = {1178-1185}, doi = {10.1080/10286020.2016.1194829}, pmid = {27314764}, issn = {1477-2213}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Biphenyl Compounds/analysis/chemistry/*pharmacology ; DNA/analysis ; Lignans/analysis/chemistry/*pharmacology ; Molecular Structure ; Staphylococcus aureus/*drug effects ; }, abstract = {Staphylococcus aureus (S. aureus) can attach to food, host tissues and the surfaces of medical implants and form a biofilm, which makes it difficult to eliminate. The purpose of this study was to evaluate the effect of honokiol on biofilm-grown S. aureus. In this report, honokiol showed effective antibacterial activity against S. aureus in biofilms. S. aureus isolates are capable of producing distinct types of biofilms mediated by polysaccharide intercellular adhesion (PIA) or extracellular DNA (eDNA). The biofilms' susceptibility to honokiol was evaluated using confocal laser scanning microscopy (CLSM) analysis. The transcript levels of the biofilm-related genes, the expression of PIA, and the amount of eDNA of biofilm-grown S. aureus exposed to honokiol were also investigated. The results of this study show that honokiol can detach existing biofilms, kill bacteria in biofilms, and simultaneously inhibit the transcript levels of sarA, cidA and icaA, eDNA release, and the expression of PIA.}, } @article {pmid27314530, year = {2016}, author = {Miklossy, J}, title = {Bacterial Amyloid and DNA are Important Constituents of Senile Plaques: Further Evidence of the Spirochetal and Biofilm Nature of Senile Plaques.}, journal = {Journal of Alzheimer's disease : JAD}, volume = {53}, number = {4}, pages = {1459-1473}, pmid = {27314530}, issn = {1875-8908}, mesh = {Alzheimer Disease/metabolism/microbiology/pathology ; Amyloid/*analysis ; *Biofilms ; Borrelia burgdorferi/genetics/*physiology ; Brain/pathology ; *Brain Chemistry ; DNA, Bacterial/*analysis ; Humans ; Immunohistochemistry ; In Situ Hybridization ; In Situ Nick-End Labeling ; Plaque, Amyloid/*chemistry/genetics/*microbiology/pathology ; }, abstract = {It has long been known that spirochetes form clumps or micro colonies in vitro and in vivo. Cortical spirochetal colonies in syphilitic dementia were considered as reproductive centers for spirochetes. Historic and recent data demonstrate that senile plaques in Alzheimer's disease (AD) are made up by spirochetes. Spirochetes, are able to form biofilm in vitro. Senile plaques are also reported to contain elements of biofilm constituents. We expected that AβPP and Aβ (the main components of senile plaques) also occur in pure spirochetal biofilms, and bacterial DNA (an important component of biofilm) is also present in senile plaques. Histochemical, immunohistochemical, and in situ hybridization techniques and the TUNEL assay were used to answer these questions. The results obtained demonstrate that Aβ and DNA, including spirochete-specific DNA, are key components of both pure spirochetal biofilms and senile plaques in AD and confirm the biofilm nature of senile plaques. These results validate validate previous observations that AβPP and/or an AβPP-like amyloidogenic protein are an integral part of spirochetes, and indicate that bacterial and host derived Aβ are both constituents of senile plaques. DNA fragmentation in senile plaques further confirms their bacterial nature and provides biochemical evidence for spirochetal cell death. Spirochetes evade host defenses, locate intracellularly, form more resistant atypical forms and notably biofilms, which contribute to sustain chronic infection and inflammation and explain the slowly progressive course of dementia in AD. To consider co-infecting microorganisms is equally important, as multi-species biofilms result in a higher resistance to treatments and a more severe dementia.}, } @article {pmid27314029, year = {2016}, author = {Yang, Y and Liu, S and He, Y and Chen, Z and Li, M}, title = {Effect of LongZhang Gargle on Biofilm Formation and Acidogenicity of Streptococcus mutans In Vitro.}, journal = {BioMed research international}, volume = {2016}, number = {}, pages = {5829823}, pmid = {27314029}, issn = {2314-6141}, mesh = {Acids/metabolism ; Biofilms/*drug effects/growth & development ; Dental Caries/*drug therapy/microbiology/pathology ; Drugs, Chinese Herbal/*pharmacology ; Humans ; Polysaccharides, Bacterial/biosynthesis ; Streptococcus mutans/*drug effects/growth & development/pathogenicity ; }, abstract = {Streptococcus mutans, with the ability of high-rate acid production and strong biofilm formation, is considered the predominant bacterial species in the pathogenesis of human dental caries. Natural products which may be bioactive against S. mutans have become a hot spot to researches to control dental caries. LongZhang Gargle, completely made from Chinese herbs, was investigated for its effects on acid production and biofilm formation by S. mutans in this study. The results showed an antimicrobial activity of LongZhang Gargle against S. mutans planktonic growth at the minimum inhibitory concentration (MIC) of 16% and minimum bactericidal concentration (MBC) of 32%. Acid production was significantly inhibited at sub-MIC concentrations. Biofilm formation was also significantly disrupted, and 8% was the minimum concentration that resulted in at least 50% inhibition of biofilm formation (MBIC50). A scanning electron microscopy (SEM) showed an effective disruption of LongZhang Gargle on S. mutans biofilm integrity. In addition, a confocal laser scanning microscopy (CLSM) suggested that the extracellular polysaccharides (EPS) synthesis could be inhibited by LongZhang Gargle at a relatively low concentration. These findings suggest that LongZhang Gargle may be a promising natural anticariogenic agent in that it suppresses planktonic growth, acid production, and biofilm formation against S. mutans.}, } @article {pmid27313658, year = {2016}, author = {Wang, X and Hao, M and Du, X and Wang, G and Matsushita, J}, title = {The Mechanical Analysis of the Biofilm Streamer Nucleation and Geometry Characterization in Microfluidic Channels.}, journal = {Computational and mathematical methods in medicine}, volume = {2016}, number = {}, pages = {7819403}, pmid = {27313658}, issn = {1748-6718}, mesh = {*Bacterial Adhesion ; *Biofilms ; Computer Simulation ; Finite Element Analysis ; Hydrodynamics ; Hydrogen-Ion Concentration ; *Lab-On-A-Chip Devices ; Materials Testing ; *Microfluidics ; Models, Theoretical ; Polymers/chemistry ; Shear Strength ; Stress, Mechanical ; Surface Properties ; Temperature ; Viscosity ; }, abstract = {Bacteria can form biofilm streamers in microfluidic channels with various geometries. Experiments show that the streamer geometry, such as its shape or thickness, depends on the fluid velocity and the geometry and curvature of the microfluidic channel. In the paper, a mechanical analysis of the flow field is made in different channels, which shows that the secondary flow in the channel is the reason for streamer nucleation and that the shear stress distribution decides the streamer geometry including shape and thickness. Through a finite elements simulation, we obtain the secondary flow forming positions in both static and rotating channels: positions that are the location of nucleation of the streamer. Thick or wide biofilm streamers occur at the points of minimum shear stress in static channels. Furthermore, in rotating channels, spiral-like streamers form, due to the helical shape of the minimum shear stress distribution. The findings may allow the prevention of biofilm formation and also the removal of bacteria adhered onto certain surfaces in channels with small cross sections. The analysis also indicates how one can obtain desirable biofilm streamers by control of the channel geometry and the loading conditions.}, } @article {pmid27313576, year = {2016}, author = {Carrouel, F and Viennot, S and Santamaria, J and Veber, P and Bourgeois, D}, title = {Quantitative Molecular Detection of 19 Major Pathogens in the Interdental Biofilm of Periodontally Healthy Young Adults.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {840}, pmid = {27313576}, issn = {1664-302X}, abstract = {In oral health, the interdental spaces are a real ecological niche for which the body has few or no alternative defenses and where the traditional daily methods for control by disrupting biofilm are not adequate. The interdental spaces are the source of many hypotheses regarding their potential associations with and/or causes of cardiovascular disease, diabetes, chronic kidney disease, degenerative disease, and depression. This PCR study is the first to describe the interdental microbiota in healthy adults aged 18-35 years-old with reference to the Socransky complexes. The complexes tended to reflect microbial succession events in developing dental biofilms. Early colonizers included members of the yellow, green, and purple complexes. The orange complex bacteria generally appear after the early colonizers and include many putative periodontal pathogens, such as Fusobacterium nucleatum. The red complex (Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) was considered the climax community and is on the list of putative periodontal pathogens. The 19 major periodontal pathogens tested were expressed at various levels. F. nucleatum was the most abundant species, and the least abundant were Actinomyces viscosus, P. gingivalis, and Aggregatibacter actinomycetemcomitans. The genome counts for Eikenella corrodens, Campylobacter concisus, Campylobacter rectus, T. denticola, and Tannerella forsythensis increased significantly with subject age. The study highlights the observation that bacteria from the yellow complex (Streptococcus spp., S. mitis), the green complex (E. corrodens, Campylobacter gracilis, Capnocytophaga ochracea, Capnocytophaga sputigena, A. actinomycetemcomitans), the purple complex (Veillonella parvula, Actinomyces odontolyticus) and the blue complex (A. viscosus) are correlated. Concerning the orange complex, F. nucleatum is the most abundant species in interdental biofilm. The red complex, which is recognized as the most important pathogen in adult periodontal disease, represents 8.08% of the 19 bacteria analyzed. P. gingivalis was detected in 19% of healthy subjects and represents 0.02% of the interdental biofilm. T. forsythensis and T. denticola (0.02 and 0.04% of the interdental biofilm) were detected in 93 and 49% of healthy subjects, respectively. The effective presence of periodontal pathogens is a strong indicator of the need to develop new methods for disrupting interdental biofilm in daily oral hygiene.}, } @article {pmid27313306, year = {2016}, author = {Hong, J and Kim, J and Kim, BY and Park, JW and Ryu, JG and Roh, E}, title = {Complete Genome Sequence of Biofilm-Forming Strain Staphylococcus haemolyticus S167.}, journal = {Genome announcements}, volume = {4}, number = {3}, pages = {}, pmid = {27313306}, issn = {2169-8287}, abstract = {Staphylococcus haemolyticus S167 has the ability to produce biofilms in large quantities. Genomic analyses revealed information on the biofilm-related genes of S. haemolyticus S167. Detailed studies of biofilm formation at the molecular level could provide a foundation for biofilm control research.}, } @article {pmid27313289, year = {2016}, author = {Morohoshi, T and Ikeda, T}, title = {Complete Genome Sequence of Methylobacterium populi P-1M, Isolated from Pink-Pigmented Household Biofilm.}, journal = {Genome announcements}, volume = {4}, number = {3}, pages = {}, pmid = {27313289}, issn = {2169-8287}, abstract = {Methylobacterium populi P-1M is isolated from the pink-pigmented household biofilm. Here, we present the complete genome sequence of P-1M, consisting of one chromosome of 5,705,640 bp and five plasmids of 64,864 bp, 59,879 bp, 42,569 bp, 41,417 bp, and 29,506 bp.}, } @article {pmid27312701, year = {2016}, author = {Kröber, M and Verwaaijen, B and Wibberg, D and Winkler, A and Pühler, A and Schlüter, A}, title = {Comparative transcriptome analysis of the biocontrol strain Bacillus amyloliquefaciens FZB42 as response to biofilm formation analyzed by RNA sequencing.}, journal = {Journal of biotechnology}, volume = {231}, number = {}, pages = {212-223}, doi = {10.1016/j.jbiotec.2016.06.013}, pmid = {27312701}, issn = {1873-4863}, mesh = {Bacillus amyloliquefaciens/*genetics/metabolism ; Bacterial Proteins/analysis/genetics/metabolism ; *Biofilms ; Gene Expression Profiling ; Gene Expression Regulation ; RNA, Bacterial/*analysis/genetics/metabolism ; RNA, Messenger/*analysis/genetics/metabolism ; Sequence Analysis, RNA ; Transcriptome/*genetics ; }, abstract = {The strain Bacillus amyloliquefaciens FZB42 is a plant growth promoting rhizobacterium (PGPR) and biocontrol agent known to keep infections of lettuce (Lactuca sativa) by the phytopathogen Rhizoctonia solani down. Several mechanisms, including the production of secondary metabolites possessing antimicrobial properties and induction of the host plant's systemic resistance (ISR), were proposed to explain the biocontrol effect of the strain. B. amyloliquefaciens FZB42 is able to form plaques (biofilm-like structures) on plant roots and this feature was discussed to be associated with its biocontrol properties. For this reason, formation of B. amyloliquefaciens biofilms was studied at the transcriptional level using high-throughput sequencing of whole transcriptome cDNA libraries from cells grown under biofilm-forming conditions vs. planktonic growth. Comparison of the transcriptional profiles of B. amyloliquefaciens FZB42 under these growth conditions revealed a common set of highly transcribed genes mostly associated with basic cellular functions. The lci gene, encoding an antimicrobial peptide (AMP), was among the most highly transcribed genes of cells under both growth conditions suggesting that AMP production may contribute to biocontrol. In contrast, gene clusters coding for synthesis of secondary metabolites with antimicrobial properties were only moderately transcribed and not induced in biofilm-forming cells. Differential gene expression revealed that 331 genes were significantly up-regulated and 230 genes were down-regulated in the transcriptome of B. amyloliquefaciens FZB42 under biofilm-forming conditions in comparison to planktonic cells. Among the most highly up-regulated genes, the yvqHI operon, coding for products involved in nisin (class I bacteriocin) resistance, was identified. In addition, an operon whose products play a role in fructosamine metabolism was enhanced in its transcription. Moreover, genes involved in the production of the extracellular biofilm matrix including exopolysaccharide genes (eps) and the yqxM-tasA-sipW operon encoding amyloid fiber synthesis were up-regulated in the B. amyloliquefaciens FZB42 biofilm. On the other hand, highly down-regulated genes in biofilms are associated with synthesis, assembly and regulation of the flagellar apparatus, the degradation of aromatic compounds and the export of copper. The obtained transcriptional profile for B. amyloliquefaciens biofilm cells uncovered genes involved in its development and enabled the assessment that synthesis of secondary metabolites among other factors may contribute to the biocontrol properties of the strain.}, } @article {pmid27309801, year = {2016}, author = {Mello, TP and Aor, AC and Gonçalves, DS and Seabra, SH and Branquinha, MH and Santos, AL}, title = {Assessment of biofilm formation by Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {737-749}, doi = {10.1080/08927014.2016.1192610}, pmid = {27309801}, issn = {1029-2454}, mesh = {A549 Cells ; Ascomycota/*physiology/ultrastructure ; Bacterial Adhesion ; Biofilms/*growth & development ; Biomass ; Epithelial Cells/*microbiology ; Humans ; Hyphae/*growth & development ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; *Polystyrenes/chemistry ; Scedosporium/*physiology/ultrastructure ; }, abstract = {Reported herein is the ability of Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans conidia to adhere, differentiate into hyphae and form biofilms on both polystyrene and lung epithelial cells. To different degrees, all of the fungi adhered to polystyrene after 4 h, with a predominance of those with germinated conidia. Prolonged fungi-polystyrene contact resulted in the formation of a monolayer of intertwined mycelia, which was identified as a typical biofilm structure due to the presence of a viable mycelial biomass, extracellular matrix and enhanced antifungal resistance. Ultrastructural details were revealed by SEM and CLSM, showing the dense compaction of the mycelial biomass and the presence of channels within the organized biofilm. A similar biofilm structure was observed following the co-culture of each fungus with A549 cells, revealing a mycelial trap covering all of the lung epithelial monolayer. Collectively, these results highlight the potential for biofilm formation by these clinically relevant fungal pathogens.}, } @article {pmid27309535, year = {2016}, author = {Adappa, ND and Truesdale, CM and Workman, AD and Doghramji, L and Mansfield, C and Kennedy, DW and Palmer, JN and Cowart, BJ and Cohen, NA}, title = {Correlation of T2R38 taste phenotype and in vitro biofilm formation from nonpolypoid chronic rhinosinusitis patients.}, journal = {International forum of allergy & rhinology}, volume = {6}, number = {8}, pages = {783-791}, pmid = {27309535}, issn = {2042-6984}, support = {R01 DC013588/DC/NIDCD NIH HHS/United States ; S10 OD018125/OD/NIH HHS/United States ; }, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; *Biofilms ; Chronic Disease ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Phenylthiourea ; Pseudomonas/*physiology ; Receptors, G-Protein-Coupled/genetics/*physiology ; Rhinitis/*physiopathology ; Sinusitis/*physiopathology ; *Taste ; Young Adult ; }, abstract = {BACKGROUND: Sinonasal biofilms have been demonstrated in specimens collected from chronic rhinosinusitis (CRS) patients. Mounting evidence suggests that biofilms contribute to therapeutically recalcitrant CRS. Recently, the bitter taste receptor T2R38 has been implicated in the regulation of the sinonasal mucosal innate immune response. TAS2R38 gene polymorphisms affect receptor functionality and contribute to variations seen in sinonasal innate defense as well as taste perception reflected in gustatory sensitivity to the bitter compound phenylthiocarbamide (PTC). In a population of CRS patients with active infection or inflammation, we sought to determine if a correlation between T2R38 phenotype and in vitro biofilm formation existed.

METHODS: Endoscopically guided sinonasal swabs were obtained prospectively from CRS (±polyp) patients with evidence of persistent inflammation or mucopurulence. In vitro biofilm formation was assessed with a modified Calgary Biofilm Detection Assay. Patients' phenotypic (functional) expression of the bitter taste receptor T2R38 was evaluated with a taste test including the compound PTC. Linear regression was used to determine the level of significance between mean in vitro biofilm formation levels and mean PTC taste test intensity ratings across CRS patients.

RESULTS: Sinonasal swabs were obtained from 59 patients, with 42 of the 59 samples demonstrating in vitro biofilm formation. Analysis revealed an inverse linear association between in vitro biofilm formation and PTC taste intensity ratings (p = 0.019) for all patients. This association was exclusively driven by nonpolypoid CRS patients (p = 0.0026).

CONCLUSION: In vitro biofilm formation from sinonasal clinical isolates is inversely correlated with PTC taste sensitivity in nonpolypoid CRS patients.}, } @article {pmid27306553, year = {2016}, author = {Liébana, R and Arregui, L and Santos, A and Murciano, A and Marquina, D and Serrano, S}, title = {Unravelling the interactions among microbial populations found in activated sludge during biofilm formation.}, journal = {FEMS microbiology ecology}, volume = {92}, number = {9}, pages = {}, doi = {10.1093/femsec/fiw134}, pmid = {27306553}, issn = {1574-6941}, mesh = {Acyl-Butyrolactones/*metabolism ; Bacteria/isolation & purification/metabolism ; Bacterial Adhesion ; Bacterial Physiological Phenomena ; Biofilms/*growth & development ; *Microbial Interactions ; Sewage/*microbiology ; Yeasts/isolation & purification/metabolism/physiology ; }, abstract = {Microorganisms colonize surfaces and develop biofilms through interactions that are not yet thoroughly understood, with important implications for water and wastewater systems. This study investigated the interactions between N-acyl homoserine lactone (AHL)-producing bacteria, yeasts and protists, and their contribution to biofilm development. Sixty-one bacterial strains were isolated from activated sludge and screened for AHL production, with Aeromonas sp. found to be the dominant AHL producer. Shewanella xiamenensis, Aeromonas allosaccharophila, Acinetobacter junii and Pseudomonas aeruginosa recorded the highest adherence capabilities, with S. xiamenensis being the most effective in surface colonization. Additionally, highly significant interactions (i.e. synergic or antagonistic) were described for dual and multistrain mixtures of bacterial strains (P. aeruginosa, S. xiamenensis, A. junii and Pseudomonas stutzeri), as well as for strongly adherent bacteria co-cultured with yeasts. In this last case, the adhered biomass in co-cultures was lower than the monospecific biofilms of bacteria and yeast, with biofilm observations by microscopy suggesting that bacteria had an antagonist effect on the whole or part of the yeast population. Finally, protist predation by Euplotes sp. and Paramecium sp. on Aeromonas hydrophila biofilms not only failed to reduce biofilm formation, but also recorded unexpected results leading to the development of aggregates of high density and complexity.}, } @article {pmid27306252, year = {2016}, author = {Aleti, G and Lehner, S and Bacher, M and Compant, S and Nikolic, B and Plesko, M and Schuhmacher, R and Sessitsch, A and Brader, G}, title = {Surfactin variants mediate species-specific biofilm formation and root colonization in Bacillus.}, journal = {Environmental microbiology}, volume = {18}, number = {8}, pages = {2634-2645}, doi = {10.1111/1462-2920.13405}, pmid = {27306252}, issn = {1462-2920}, mesh = {Animals ; Antifungal Agents/*metabolism ; Bacillus/classification/genetics/*metabolism ; Biofilms/*growth & development ; Lipopeptides/genetics/*metabolism ; Peptides, Cyclic/genetics/*metabolism ; Plant Diseases/microbiology ; Plant Roots/microbiology ; Rhizoctonia/*growth & development ; }, abstract = {Cyclic lipopeptides (cLP) and especially surfactins produced by Bacillus spp. trigger biofilm formation and root colonization and are crucial for biocontrol activity and systemic resistance in plants. Bacillus atrophaeus 176s isolated from the moss Tortella tortuosa produces the cLP fengycins, iturins and surfactins, possesses antifungal activities and can protect tomato, lettuce and sugar beet against Rhizoctonia solani infection. In B. atrophaeus we identified for the first time the variant surfactin C, which differs from surfactin A produced by B. subtilis and B. amyloliquefaciens by an isoleucine instead of a leucine at position 7 of the lipopeptide backbone. The analysis of the complete surfactin gene clusters revealed that the dissimilarity is encoded in the adenylation domain of srfC and show that surfactin variations are distributed in a species-specific manner in bacilli. We demonstrate that the surfactin A and C with subtle structural differences have varying signal strengths on biofilm formation and root colonization and act specifically on the respective producing strain. This became evident as biofilm formation and root colonization but not swarming motility in surfactin biosynthesis mutants was restored differentially in the presence of exogenously supplemented cognate and non-cognate surfactin variants.}, } @article {pmid27306110, year = {2016}, author = {Skagia, A and Zografou, C and Vezyri, E and Venieraki, A and Katinakis, P and Dimou, M}, title = {Cyclophilin PpiB is involved in motility and biofilm formation via its functional association with certain proteins.}, journal = {Genes to cells : devoted to molecular & cellular mechanisms}, volume = {21}, number = {8}, pages = {833-851}, doi = {10.1111/gtc.12383}, pmid = {27306110}, issn = {1365-2443}, mesh = {Acetyl-CoA Carboxylase/*chemistry/genetics ; Biofilms/*growth & development ; Carbon-Nitrogen Ligases/chemistry/genetics ; Cyclophilins/chemistry/*genetics ; Escherichia coli/genetics/growth & development ; Escherichia coli Proteins/chemistry/*genetics ; HSP70 Heat-Shock Proteins/chemistry/*genetics ; Phosphate Acetyltransferase/genetics ; Protein Folding ; }, abstract = {PpiB belongs to the superfamily of peptidyl-prolyl cis/trans isomerases (PPIases, EC: 5.2.1.8), which catalyze the rate-limiting protein folding step at peptidyl-prolyl bonds and control several biological processes. In this study, we show that PpiB acts as a negative effector of motility and biofilm formation ability of Escherichia coli. We identify multicopy suppressors of each ΔppiB phenotype among putative PpiB prey proteins which upon deletion are often characterized by analogous phenotypes. Many putative preys show similar gene expression in wild-type and ΔppiB genetic backgrounds implying possible post-translational modifications by PpiB. We further conducted in vivo and in vitro interaction screens to determine which of them represent true preys. For DnaK, acetyl-CoA carboxylase, biotin carboxylase subunit (AccC) and phosphate acetyltransferase (Pta) we also showed a direct role of PpiB in the functional control of these proteins because it increased the measured enzyme activity of each protein and further interfered with DnaK localization and the correct folding of AccC. Taken together, these results indicate that PpiB is involved in diverse regulatory mechanisms to negatively modulate motility and biofilm formation via its functional association with certain protein substrates.}, } @article {pmid27304227, year = {2016}, author = {An, SQ and Ryan, RP}, title = {Combating chronic bacterial infections by manipulating cyclic nucleotide-regulated biofilm formation.}, journal = {Future medicinal chemistry}, volume = {8}, number = {9}, pages = {949-961}, doi = {10.4155/fmc-2015-0002}, pmid = {27304227}, issn = {1756-8927}, support = {//Wellcome Trust/United Kingdom ; }, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Infections/*drug therapy/metabolism/*microbiology ; Biofilms/*drug effects/*growth & development ; Humans ; Microbial Sensitivity Tests ; Nucleotides, Cyclic/*metabolism ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism ; }, abstract = {Many pathogenic bacteria can form biofilms in clinical settings with major consequences for the progression of infections. Bacterial biofilm communities are typically much more resistant to both antibiotic treatment and clearance by the immune system in comparison to free-living cells. Therefore, drugs that specifically target the formation or maintenance of biofilms would be very valuable additions to current clinical options. Cyclic nucleotide second messengers, in particular cyclic-diguanosine-GMP (c-di-GMP), are now known to play a major role in biofilm formation, and maintenance, in many bacterial species. In this special report, we will review recent progress toward the development of drugs that interfere with c-di-GMP signaling as a route to control biofilm infections. We will focus on the chronic infections associated with the notorious opportunistic pathogen Pseudomonas aeruginosa, although the principles outlined here are also relevant to most bacterial pathogens.}, } @article {pmid27303652, year = {2016}, author = {Nourbakhsh, F and Namvar, AE}, title = {Detection of genes involved in biofilm formation in Staphylococcus aureus isolates.}, journal = {GMS hygiene and infection control}, volume = {11}, number = {}, pages = {Doc07}, pmid = {27303652}, issn = {2196-5226}, abstract = {Staphylococcus aureus is one of the Gram-positive pathogens causing a wide range of nosocomial infections. The present study investigates genotypic and phenotypic aspects involved in biofilm formation in methicillin-resistant Staphylococcus aureus strains isolated from nosocomial infections in Isfahan. A total of 110 S. aureus strains were collected from three major hospitals in Isfahan, the center of Iran. The antibiotic resistance pattern, phenotypes, and biofilm formation genes were studied using Congo red agar (CRA) and multiplex PCR (M-PCR). We found that 103 out of 110 samples (93.6%) were MRSA. The highest frequency of resistance was found to penicillin (89%), ciprofloxacin (87.4%), and erythromycin (86.1%). Phenotypic results showed that 53.5% were high biofilm producers, while 33.3% and 13.2% were intermediate and low biofilm producers, respectively. icaC (69.3%) had the highest frequency in comparison to other intercellular adhesion (ica) genes, icaD (54.8%) was second most common. The results show that the adherence or attachment ability and biofilm production are important for enhancing virulence factors among isolates of S. aureus strains.}, } @article {pmid27303616, year = {2016}, author = {Kwiecinska-Pirog, J and Skowron, K and Bartczak, W and Gospodarek-Komkowska, E}, title = {The Ciprofloxacin Impact on Biofilm Formation by Proteus Mirabilis and P. Vulgaris Strains.}, journal = {Jundishapur journal of microbiology}, volume = {9}, number = {4}, pages = {e32656}, pmid = {27303616}, issn = {2008-3645}, abstract = {BACKGROUND: Proteus spp. bacilli belong to opportunistic human pathogens, which are primarily responsible for urinary tract and wound infections. An important virulence factor is their ability to form biofilms that greatly reduce the effectiveness of antibiotics in the site of infection.

OBJECTIVES: The aim of this study was to determine the value of the minimum concentration of ciprofloxacin that eradicates a biofilm of Proteus spp. strains.

MATERIALS AND METHODS: A biofilm formation of 20 strains of P. mirabilis and 20 strains of P. vulgaris were evaluated by a spectrophotometric method using 0.1% 2, 3, 5-Triphenyl-tetrazolium chloride solution (TTC, AVANTORTM). On the basis of the results of the absorbance of the formazan, a degree of reduction of biofilm and minimum biofilm eradication (MBE) values of MBE50 and MBE90 were determined.

RESULTS: All tested strains formed a biofilm. A value of 1.0 μg/mL ciprofloxacin is MBE50 for the strains of both tested species. An MBE90 value of ciprofloxacin for isolates of P. vulgaris was 2 μg/mL and for P. mirabilis was 512 μg/mL.

CONCLUSIONS: Minimum biofilm eradication values of ciprofloxacin obtained in the study are close to the values of the minimal inhibition concentration (MIC).}, } @article {pmid27303396, year = {2016}, author = {Al Atya, AK and Belguesmia, Y and Chataigne, G and Ravallec, R and Vachée, A and Szunerits, S and Boukherroub, R and Drider, D}, title = {Anti-MRSA Activities of Enterocins DD28 and DD93 and Evidences on Their Role in the Inhibition of Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {817}, pmid = {27303396}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has become a worrisome superbug. This work aimed at studying the effects of two class IIb bacteriocins, enterocins DD28 and DD93 as anti-MRSA agents. Thus, these bacteriocins were purified, from the cultures supernatants of Enterococcus faecalis 28 and 93, using a simplified purification procedure consisting in a cation exchange chromatography and a reversed-phase high-performance liquid chromatography. The anti-Staphylococcal activity was shown in vitro by the assessment of the minimal inhibitory concentration (MIC), followed by a checkerboard and time-kill kinetics experiments. The data unveiled a clear synergistic effect of enterocins DD28 and DD93 in combination with erythromycin or kanamycin against the clinical MRSA-S1 strain. Besides, these combinations impeded as well the MRSA-S1 clinical strain to setup biofilms on stainless steel and glace devices.}, } @article {pmid27302761, year = {2016}, author = {Cogan, NG and Harro, JM and Stoodley, P and Shirtliff, ME}, title = {Predictive Computer Models for Biofilm Detachment Properties in Pseudomonas aeruginosa.}, journal = {mBio}, volume = {7}, number = {3}, pages = {}, pmid = {27302761}, issn = {2150-7511}, mesh = {*Biofilms ; Plankton ; *Pseudomonas aeruginosa ; }, abstract = {Microbial biofilm communities are protected against environmental extremes or clearance by antimicrobial agents or the host immune response. They also serve as a site from which microbial populations search for new niches by dispersion via single planktonic cells or by detachment by protected biofilm aggregates that, until recently, were thought to become single cells ready for attachment. Mathematically modeling these events has provided investigators with testable hypotheses for further study. Such was the case in the recent article by Kragh et al. (K. N. Kragh, J. B. Hutchison, G. Melaugh, C. Rodesney, A. E. Roberts, Y. Irie, P. Ø. Jensen, S. P. Diggle, R. J. Allen, V. Gordon, and T. Bjarnsholt, mBio 7:e00237-16, 2016, http://dx.doi.org/10.1128/mBio.00237-16), in which investigators were able to identify the differential competitive advantage of biofilm aggregates to directly attach to surfaces compared to the single-celled planktonic populations. Therefore, as we delve deeper into the properties of the biofilm mode of growth, not only do we need to understand the complexity of biofilms, but we must also account for the properties of the dispersed and detached populations and their effect on reseeding.}, } @article {pmid27299565, year = {2016}, author = {Zhang, Y and Pei, G and Chen, L and Zhang, W}, title = {Metabolic dynamics of Desulfovibrio vulgaris biofilm grown on a steel surface.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {725-736}, doi = {10.1080/08927014.2016.1193166}, pmid = {27299565}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Carbon/chemistry/metabolism ; Chromatography, Liquid ; Corrosion ; Desulfovibrio vulgaris/*metabolism/*physiology ; Fatty Acids/biosynthesis/metabolism ; Gas Chromatography-Mass Spectrometry ; Metabolomics/*methods ; Plankton/metabolism/physiology ; *Steel/chemistry ; }, abstract = {In this study, a comparative metabolomics approach combining gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) was applied first between planktonic cells and biofilms and then between pure cultures and biofilms of Desulfovibrio vulgaris. The results revealed that the overall metabolic level of the biofilm cells was down-regulated, especially for metabolites related to the central carbon metabolism, compared to the planktonic cells and the pure culture of D. vulgaris. In addition, pathway enrichment analysis of the 58 metabolites identified by GC-MS showed that fatty acid biosynthesis in the biofilm cells was up-regulated, suggesting that fatty acids may be important for the formation, maintenance and function of D. vulgaris biofilm. This study offers a valuable perspective on the metabolic dynamics of the D. vulgaris biofilm.}, } @article {pmid27297485, year = {2016}, author = {Bayer, AS and Abdelhady, W and Li, L and Gonzales, R and Xiong, YQ}, title = {Comparative Efficacies of Tedizolid Phosphate, Linezolid, and Vancomycin in a Murine Model of Subcutaneous Catheter-Related Biofilm Infection Due to Methicillin-Susceptible and -Resistant Staphylococcus aureus.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {8}, pages = {5092-5096}, pmid = {27297485}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Catheter-Related Infections/drug therapy/microbiology ; Linezolid/*therapeutic use ; Methicillin/*therapeutic use ; Methicillin-Resistant Staphylococcus aureus/*drug effects/pathogenicity ; Mice ; Organophosphates/*therapeutic use ; Oxazoles/*therapeutic use ; Staphylococcus aureus/drug effects/pathogenicity ; Vancomycin/*therapeutic use ; }, abstract = {Tedizolid, a novel oxazolidinone, exhibits bacteriostatic activity through inhibition of protein synthesis. The efficacies of tedizolid, linezolid, and vancomycin were compared in a murine catheter-related biofilm infection caused by methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) strains engineered for bioluminescence. We observed significantly improved efficacy in terms of decreased S. aureus densities and bioluminescent signals in the tedizolid-treated group versus the linezolid- and vancomycin-treated groups in the model of infection caused by the MSSA and MRSA strains.}, } @article {pmid27294580, year = {2016}, author = {Lee, KJ and Lee, MA and Hwang, W and Park, H and Lee, KH}, title = {Deacylated lipopolysaccharides inhibit biofilm formation by Gram-negative bacteria.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {711-723}, doi = {10.1080/08927014.2016.1193595}, pmid = {27294580}, issn = {1029-2454}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Gram-Negative Bacteria/*drug effects/genetics/physiology ; Gram-Positive Bacteria/drug effects/genetics/physiology ; Lipopolysaccharides/*pharmacology ; Teichoic Acids/*pharmacology ; }, abstract = {The extracellular polysaccharides of Vibrio vulnificus play different roles during biofilm development. Among them, the effect of lipopolysaccharide (LPS), which is crucial for bacterial adherence to surfaces during the initial stage of biofilm formation, on the formation process was examined using various types of LPS extracts. Exogenously added LPS strongly inhibited biofilm formation in a dose-dependent manner. In addition, the exogenous addition of a deacylated form of LPS (dLPS) also inhibited biofilm formation. However, an LPS fraction extracted from a mutant not able to produce O-antigen polysaccharides (O-Ag) did not have an inhibitory effect. Furthermore, biofilm formation by several Gram-negative bacteria was inhibited by dLPS addition. In contrast, biofilm formation by Gram-positive bacteria was not influenced by dLPS but was affected by lipoteichoic acid. Therefore, this study demonstrates that O-Ag in LPS is important for inhibiting biofilm formation and may serve an efficient anti-biofilm agent specific for Gram-negative bacteria.}, } @article {pmid27295353, year = {2016}, author = {Ozturk, B and Gunay, N and Ertugrul, BM and Sakarya, S}, title = {Effects of vancomycin, daptomycin, and tigecycline on coagulase-negative staphylococcus biofilm and bacterial viability within biofilm: an in vitro biofilm model.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {9}, pages = {735-743}, doi = {10.1139/cjm-2015-0855}, pmid = {27295353}, issn = {1480-3275}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Biofilms/drug effects ; Coagulase/metabolism ; Daptomycin/*pharmacology ; Microbial Viability/drug effects ; Minocycline/*analogs & derivatives/pharmacology ; Models, Biological ; Staphylococcus/*drug effects/enzymology ; Tigecycline ; Vancomycin/*pharmacology ; }, abstract = {Bacteria may hide in a hydrated polysaccharide matrix known as a biofilm. The structure of the bacterial biofilm renders phagocytosis difficult and increases antibiotic resistance. We hypothesized that repeated doses of antibiotics have an effect on bacteria within the biofilm and that it could inhibit or eradicate biofilm formation. Two clinical biofilm-positive coagulase-negative staphylococcus isolates were evaluated. The effects of antibiotics on preformed and nascent biofilm and on bacterial eradication within the biofilm were determined using different doses of vancomycin, daptomycin, and tigecycline for different durations in an in vitro biofilm model. Vancomycin neither penetrated the biofilm nor had any microbicidal effect on bacteria within the biofilm. Daptomycin had a microbicidal effect on bacteria within the biofilm but had no effect on biofilm inhibition and eradication (independent from dose and treatment time). Tigecycline inhibited and eradicated biofilm formation and had a microbicidal effect on bacteria within the biofilm. In conclusion, (i) biofilm formation appeared to be a major barrier to vancomycin activity, (ii) daptomycin had an antimicrobial effect on the bacteria within the biofilm but not on the biofilm burden, and (iii) tigecycline had effects both on bacteria within the biofilm and on biofilm burden. Thus, both tigecycline and daptomycin might be promising candidates for the treatment of biofilm infections.}, } @article {pmid27294544, year = {2016}, author = {Gao, L and Liu, Y and Kim, D and Li, Y and Hwang, G and Naha, PC and Cormode, DP and Koo, H}, title = {Nanocatalysts promote Streptococcus mutans biofilm matrix degradation and enhance bacterial killing to suppress dental caries in vivo.}, journal = {Biomaterials}, volume = {101}, number = {}, pages = {272-284}, pmid = {27294544}, issn = {1878-5905}, support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; S10 RR027128/RR/NCRR NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biocompatible Materials/chemistry/pharmacology ; Biofilms/*drug effects ; Catalysis ; Cell Line ; Dental Caries/drug therapy/metabolism/microbiology ; Ferrosoferric Oxide/*chemistry/*pharmacology ; Humans ; Hydrogen Peroxide/metabolism ; Nanoparticles/*chemistry ; Peroxidase/chemistry/pharmacology ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {Dental biofilms (known as plaque) are notoriously difficult to remove or treat because the bacteria can be enmeshed in a protective extracellular matrix. It can also create highly acidic microenvironments that cause acid-dissolution of enamel-apatite on teeth, leading to the onset of dental caries. Current antimicrobial agents are incapable of disrupting the matrix and thereby fail to efficiently kill the microbes within plaque-biofilms. Here, we report a novel strategy to control plaque-biofilms using catalytic nanoparticles (CAT-NP) with peroxidase-like activity that trigger extracellular matrix degradation and cause bacterial death within acidic niches of caries-causing biofilm. CAT-NP containing biocompatible Fe3O4 were developed to catalyze H2O2 to generate free-radicals in situ that simultaneously degrade the biofilm matrix and rapidly kill the embedded bacteria with exceptional efficacy (>5-log reduction of cell-viability). Moreover, it displays an additional property of reducing apatite demineralization in acidic conditions. Using 1-min topical daily treatments akin to a clinical situation, we demonstrate that CAT-NP in combination with H2O2 effectively suppress the onset and severity of dental caries while sparing normal tissues in vivo. Our results reveal the potential to exploit nanocatalysts with enzyme-like activity as a potent alternative approach for treatment of a prevalent biofilm-associated oral disease.}, } @article {pmid27292911, year = {2016}, author = {Weiser, J and Henke, HA and Hector, N and Both, A and Christner, M and Büttner, H and Kaplan, JB and Rohde, H}, title = {Sub-inhibitory tigecycline concentrations induce extracellular matrix binding protein Embp dependent Staphylococcus epidermidis biofilm formation and immune evasion.}, journal = {International journal of medical microbiology : IJMM}, volume = {306}, number = {6}, pages = {471-478}, doi = {10.1016/j.ijmm.2016.05.015}, pmid = {27292911}, issn = {1618-0607}, mesh = {Animals ; Anti-Bacterial Agents/*metabolism ; Bacterial Proteins/*biosynthesis/genetics ; Biofilms/*growth & development ; Carrier Proteins/*biosynthesis/genetics ; Cell Line ; Gene Expression Profiling ; Humans ; *Immune Evasion ; Immunoblotting ; Macrophages/microbiology ; Mice ; Microscopy, Confocal ; Minocycline/*analogs & derivatives/metabolism ; Phagocytosis ; Real-Time Polymerase Chain Reaction ; Staphylococcus epidermidis/*drug effects/immunology/metabolism/*physiology ; Tigecycline ; Trans-Activators/biosynthesis/genetics ; }, abstract = {Biofilm-associated Staphylococcus epidermidis implant infections are notoriously reluctant to antibiotic treatment. Here we studied the effect of sub-inhibitory concentrations of penicillin, oxacillin, vancomycin, daptomycin, linezolid and tigecycline on S. epidermidis 1585 biofilm formation, expression of extracellular matrix binding protein (Embp) and potential implications for S. epidermidis - macrophage interactions. Penicillin, vancomycin, daptomycin, and linezolid had no biofilm augmenting effect at any of the concentrations tested. In contrast, at sub-inhibitory concentrations tigecycline and oxacillin exhibited significant biofilm inducing activity. In S. epidermidis 1585, SarA is a negative regulator of giant 1 MDa Embp, and down regulation of sarA induces Embp-dependent assembly of a multi-layered biofilm architecture. Dot blot immune assays, confocal laser scanning microscopy, and qPCR showed that under biofilm inducing conditions, tigecycline augmented embp expression compared to the control grown without antibiotics. Conversely, expression of regulator sarA was suppressed, suggesting that tigecycline exerts its effects on embp expression through SarA. Tigecycline failed to induce biofilm formation in embp transposon mutant 1585-M135, proving that under these conditions Embp up-regulation is necessary for biofilm accumulation. As a functional consequence, tigecycline induced biofilm formation significantly impaired the up-take of S. epidermidis by mouse macrophage-like cell line J774A.1. Our data provide novel evidence for the molecular basis of antibiotic induced biofilm formation, a phenotype associated with inherently increased antimicrobial tolerance. While this could explain failure of antimicrobial therapies, persistence of S. epidermidis infections in the presence of sub-inhibitory antimicrobials is additionally propelled by biofilm-related impairment of macrophage-mediated pathogen eradication.}, } @article {pmid27292570, year = {2016}, author = {Kosikowska, U and Andrzejczuk, S and Plech, T and Malm, A}, title = {Inhibitory effect of 1,2,4-triazole-ciprofloxacin hybrids on Haemophilus parainfluenzae and Haemophilus influenzae biofilm formation in vitro under stationary conditions.}, journal = {Research in microbiology}, volume = {167}, number = {8}, pages = {647-654}, doi = {10.1016/j.resmic.2016.05.009}, pmid = {27292570}, issn = {1769-7123}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Haemophilus influenzae/*drug effects/physiology ; Haemophilus parainfluenzae/*drug effects/physiology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Spectrophotometry ; Triazoles/*pharmacology ; }, abstract = {Haemophilus parainfluenzae and Haemophilus influenzae, upper respiratory tract microbiota representatives, are able to colonize natural and artificial surfaces as biofilm. The aim of the present study was to assay the effect of ten 1,2,4-triazole-ciprofloxacin hybrids on planktonic or biofilm-forming haemophili cells in vitro under stationary conditions on the basis of MICs (minimal inhibitory concentrations) and MBICs (minimal biofilm inhibitory concentrations). In addition, anti-adhesive properties of these compounds were examined. The reference strains of H. parainfluenzae and H. influenzae were included. The broth microdilution microtiter plate (MTP) method with twofold dilution of the compounds, or ciprofloxacin (reference agent) in 96-well polystyrene microplates, was used. The optical density (OD) reading was made spectrophotometrically at a wavelength of 570 nm (OD570) both to measure bacterial growth and to detect biofilm-forming cells under the same conditions with 0.1% crystal violet. The following values of parameters were estimated for 1,2,4-triazole-ciprofloxacin hybrids - MIC = 0.03-15.63 mg/L, MBIC = 0.03-15.63 mg/L, MBIC/MIC = 0.125-8, depending on the compound, and for ciprofloxacin - MIC = 0.03-0.06 mg/L, MBIC = 0.03-0.12 mg/L, MBIC/MIC = 1-2. The observed strong anti-adhesive properties (95-100% inhibition) of the tested compounds were reversible during long-term incubation at subinhibitory concentrations. Thus, 1,2,4-triazole-ciprofloxacin hybrids may be considered as starting compounds for designing improved agents not only against planktonic but also against biofilm-forming Haemophilus spp. cells.}, } @article {pmid27292548, year = {2016}, author = {Silva, ON and Alves, ES and de la Fuente-Núñez, C and Ribeiro, SM and Mandal, SM and Gaspar, D and Veiga, AS and Castanho, MA and Andrade, CA and Nascimento, JM and Fensterseifer, IC and Porto, WF and Correa, JR and Hancock, RE and Korpole, S and Oliveira, AL and Liao, LM and Franco, OL}, title = {Structural Studies of a Lipid-Binding Peptide from Tunicate Hemocytes with Anti-Biofilm Activity.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27128}, pmid = {27292548}, issn = {2045-2322}, mesh = {Animals ; Bacteria/*drug effects ; Bacterial Physiological Phenomena/drug effects ; Biofilms/*drug effects ; Blood Proteins/*chemistry/pharmacology ; Cell Membrane/drug effects ; Circular Dichroism ; Dynamic Light Scattering ; Hemocytes/chemistry/metabolism ; Lipid Bilayers/*metabolism ; Microbial Sensitivity Tests ; Molecular Docking Simulation ; Protein Structure, Secondary ; Urochordata/chemistry/*metabolism ; }, abstract = {Clavanins is a class of peptides (23aa) histidine-rich, free of post-translational modifications. Clavanins have been studied largely for their ability to disrupt bacterial membranes. In the present study, the interaction of clavanin A with membranes was assessed by dynamic light scattering, zeta potential and permeabilization assays. We observed through those assays that clavanin A lysis bacterial cells at concentrations corresponding to its MIC. Further, the structure and function of clavanin A was investigated. To better understand how clavanin interacted with bacteria, its NMR structure was elucidated. The solution state NMR structure of clavanin A in the presence of TFE-d3 indicated an α-helical conformation. Secondary structures, based on circular dichroism measurements in anionic sodium dodecyl sulfate (SDS) and TFE (2,2,2-trifluorethanol), in silico lipid-peptide docking and molecular simulations with lipids DPPC and DOPC revealed that clavanin A can adopt a variety of folds, possibly influencing its different functions. Microcalorimetry assays revealed that clavanin A was capable of discriminating between different lipids. Finally, clavanin A was found to eradicate bacterial biofilms representing a previously unrecognized function.}, } @article {pmid27291084, year = {2017}, author = {Okoye, GA and Vlassova, N and Olowoyeye, O and Agostinho, A and James, G and Stewart, PS and Leung, S and Lazarus, G}, title = {Bacterial biofilm in acute lesions of hidradenitis suppurativa.}, journal = {The British journal of dermatology}, volume = {176}, number = {1}, pages = {241-243}, doi = {10.1111/bjd.14805}, pmid = {27291084}, issn = {1365-2133}, mesh = {Acute Disease ; Adult ; *Biofilms ; Female ; Hidradenitis Suppurativa/diagnostic imaging/*microbiology ; Humans ; Male ; Microscopy, Fluorescence ; Middle Aged ; Young Adult ; }, } @article {pmid27289310, year = {2016}, author = {Abdoli, L and Suo, X and Li, H}, title = {Distinctive colonization of Bacillus sp. bacteria and the influence of the bacterial biofilm on electrochemical behaviors of aluminum coatings.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {145}, number = {}, pages = {688-694}, doi = {10.1016/j.colsurfb.2016.05.075}, pmid = {27289310}, issn = {1873-4367}, mesh = {Aluminum/*pharmacology ; Bacillus/drug effects/growth & development/*physiology/ultrastructure ; Biofilms/drug effects/*growth & development ; Coated Materials, Biocompatible/*pharmacology ; Colony Count, Microbial ; Dielectric Spectroscopy ; Electrochemistry/*methods ; Microscopy, Atomic Force ; Spectroscopy, Fourier Transform Infrared ; Stainless Steel/pharmacology ; }, abstract = {Formation of biofilm is usually essential for the development of biofouling and crucially impacts the corrosion of marine structures. Here we report the attachment behaviors of Bacillus sp. bacteria and subsequent formation of bacterial biofilm on stainless steel and thermal sprayed aluminum coatings in artificial seawater. The colonized bacteria accelerate the corrosion of the steel plates, and markedly enhance the anti-corrosion performances of the Al coatings in early growth stage of the bacterial biofilm. After 7days incubation, the biofilm formed on the steel is heterogeneous while exhibits homogeneous feature on the Al coating. Atomic force microscopy examination discloses inception of formation of local pitting on steel plates associated with significantly roughened surface. Electrochemical testing suggests that the impact of the bacterial biofilm on the corrosion behaviors of marine structures is not decided by the biofilm alone, it is instead attributed to synergistic influence by both the biofilm and physicochemical characteristics of the substratum materials.}, } @article {pmid27288863, year = {2016}, author = {Piecuch, A and Lamch, Ł and Paluch, E and Obłąk, E and Wilk, KA}, title = {Biofilm prevention by dicephalic cationic surfactants and their interactions with DNA.}, journal = {Journal of applied microbiology}, volume = {121}, number = {3}, pages = {682-692}, doi = {10.1111/jam.13204}, pmid = {27288863}, issn = {1365-2672}, mesh = {Amides/chemistry/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; DNA, Bacterial/chemistry ; Glass ; Nucleic Acid Conformation/drug effects ; Polystyrenes ; Pseudomonas aeruginosa/*drug effects/physiology ; Quaternary Ammonium Compounds/chemistry/*pharmacology ; Silicones ; Stainless Steel ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*drug effects/physiology ; Surface-Active Agents/*pharmacology ; Virulence Factors/metabolism ; }, abstract = {AIMS: The studies were aimed to contribute to the elucidation of the relationships between structure of the double-headed cationic surfactants-N,N-bis[3,3'-(dimethylamine)- propyl]alkylamide dihydrochlorides and N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dibromides (alkyl: n-C9 H19 , n-C11 H23 , n-C13 H27 , n-C15 H31) and their antibacterial and biofilm preventing activity.

METHODS AND RESULTS: The minimal inhibitory and bactericidal concentrations (MIC and MBC) of dicephalic surfactants against Staphylococcus epidermidis and Pseudomonas aeruginosa were tested using standard methods. Pseudomonas aeruginosa was resistant to studied compounds but MBC values against Staph. epidermidis reached 0·48-0·01 mmol l(-1) . The influence of dicephalic surfactants on bacterial biofilm and adhesion to the various surfaces was investigated with crystal violet staining or colony counting. The reduction in bacterial adhesion was observed, especially in the case of glass and stainless steel. The condensation of the DNA was shown in the ethidium bromide intercalation assay.

CONCLUSIONS: Dicephalic surfactants exhibited antibacterial activity against Staph. epidermidis. The activity of studied compounds depended on the hydrocarbon chain length and the counterion. Surfactants deposited on different materials reduced Staph. epidermidis adhesion, dependently on the surfactant structure and the substratum. Dicephalic surfactants showed the ability of DNA compaction.

This study points the possibility of application of dicephalic surfactants as the surface-coating agents to prevent biofilm formation. These compounds efficiently condensed DNA and are potential candidates for further studies towards the transfection.}, } @article {pmid27287850, year = {2016}, author = {Chao, Y and Mao, Y and Yu, K and Zhang, T}, title = {Novel nitrifiers and comammox in a full-scale hybrid biofilm and activated sludge reactor revealed by metagenomic approach.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {18}, pages = {8225-8237}, doi = {10.1007/s00253-016-7655-9}, pmid = {27287850}, issn = {1432-0614}, mesh = {Ammonia/*metabolism ; Bacteria/classification/genetics/metabolism ; Biofilms/*growth & development ; Bioreactors/*microbiology ; *Biota ; *Denitrification ; High-Throughput Nucleotide Sequencing ; Metagenomics ; *Nitrification ; Nitrogen/metabolism ; Oxidation-Reduction ; Phylogeny ; Polymerase Chain Reaction ; Sewage/*microbiology ; Wastewater ; Water Purification ; }, abstract = {Biofilms are widely used in wastewater treatment for their particular enhancement of nitrogen removal and other significant advantages. In this study, the diversity and potential functions of nitrogen removal bacteria in suspended activated sludge (AS) and biofilm of a full-scale hybrid reactor were uncovered by metagenomes (∼34 Gb), coupled with PCR-based 454 reads (>33 K reads). The results indicated that the diversity and abundance of nitrifiers and denitrifiers in biofilm did not surpass that in AS, while more nitrification and denitrification genes were indeed found in biofilm than AS, suggesting that the increased nitrogen removal ability by applying biofilm might be attributed to the enhancement of removal efficiency, rather than the biomass accumulation of nitrogen removal bacteria. The gene annotation and phylogenetic analysis results revealed that AS and biofilm samples consisted of 6.0 % and 9.4 % of novel functional genes for nitrogen removal and 18 % and 30 % of new Nitrospira species for nitrite-oxidizing bacteria, respectively. Moreover, the identification of Nitrospira-like amoA genes provided metagenomic evidence for the presence of complete ammonia oxidizer (comammox) with the functional potential to perform the complete oxidation of ammonia to nitrate. These findings have significant implications in expanding our knowledge of the biological nitrogen transformations in wastewater treatment.}, } @article {pmid27287466, year = {2016}, author = {Muakkassa, FK and Ghannoum, M}, title = {Updates on Therapeutic Strategies Against Candida (and Aspergillus) Biofilm Related Infections.}, journal = {Advances in experimental medicine and biology}, volume = {931}, number = {}, pages = {95-103}, doi = {10.1007/5584_2016_11}, pmid = {27287466}, issn = {0065-2598}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Aspergillosis/*drug therapy/microbiology ; Aspergillus/*drug effects/physiology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Candidiasis/*drug therapy/microbiology ; Humans ; }, abstract = {Fungal biofilm related infections are commonly associated with medical devices with biofilms contributing to the virulence of the involved fungal species. If infection does occur, removal of medical device is often warranted. However, this is not always possible. Moreover, biofilm associated infections are often resistant to antifungals and host immunity. Therefore, a need for new agents and strategies to combat these devastating infections is needed. Although no randomized clinical trials have been conducted or are likely to be conducted in the future, the Infectious Disease Society of America (IDSA) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) utilized available published data and clinical experience of the infectious disease community to propose strategies to treat biofilm associated devise infections. In this chapter we describe the emerging therapies for biofilm related infections.}, } @article {pmid27286666, year = {2016}, author = {Kanno, E and Tanno, H and Suzuki, A and Kamimatsuno, R and Tachi, M}, title = {Reconsideration of iodine in wound irrigation: the effects on Pseudomonas aeruginosa biofilm formation.}, journal = {Journal of wound care}, volume = {25}, number = {6}, pages = {335-339}, doi = {10.12968/jowc.2016.25.6.335}, pmid = {27286666}, issn = {0969-0700}, mesh = {Animals ; Anti-Infective Agents, Local/*pharmacology ; Bacterial Load/*drug effects ; Biofilms/*drug effects ; Male ; Povidone-Iodine/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride/pharmacology ; Therapeutic Irrigation/*methods ; Wounds and Injuries/pathology/*therapy ; }, abstract = {OBJECTIVE: Chronic skin wounds are usually colonised with bacteria and subsequent infection may develop. Topical antiseptics are commonly used to control bacterial colonisation. The topical antiseptic, 1% polyvinylpyrrolidone-iodine (PVP-I), that is used on chronic open skin wounds remains controversial in the clinical setting because of its cytotoxicity. Here, we tested 1% PVP-I solution against saline to determine if it reduces bacterial count on the wound surface and within the tissue that may lead to wound reduction.

METHOD: Open wounds that were created on the backs of Sprague Dawley rats were inoculated with Pseudomonas aeruginosa at the wound surface. Wounds were kept covered except for wound irrigation, two days post-wounding, wounds were irrigated daily using a 10ml syringe and spray tip.

RESULTS: Our results indicate that 1% PVP-I irrigation resulted in a reduced bacterial count on the wound surface and within the tissue compared with saline irrigation. The 1% PVP-I irrigation promoted wound re-epithelialisation compared with saline irrigation, but it did not reach significance.

CONCLUSION: These results indicated that irrigation with 1% PVP-I was an effective way to reduce bacterial count on the wound surface, and allow the wound to progress to healing.}, } @article {pmid27286663, year = {2016}, author = {Bianchi, T and Wolcott, RD and Peghetti, A and Leaper, D and Cutting, K and Polignano, R and Rosa Rita, Z and Moscatelli, A and Greco, A and Romanelli, M and Pancani, S and Bellingeri, A and Ruggeri, V and Postacchini, L and Tedesco, S and Manfredi, L and Camerlingo, M and Rowan, S and Gabrielli, A and Pomponio, G}, title = {Recommendations for the management of biofilm: a consensus document.}, journal = {Journal of wound care}, volume = {25}, number = {6}, pages = {305-317}, doi = {10.12968/jowc.2016.25.6.305}, pmid = {27286663}, issn = {0969-0700}, mesh = {Anti-Infective Agents/therapeutic use ; Anti-Infective Agents, Local/*therapeutic use ; *Bandages ; *Biofilms ; Burns/diagnosis/*therapy ; Debridement/*methods ; Diabetic Foot/diagnosis/*therapy ; Disease Management ; Humans ; Pressure Ulcer/diagnosis/*therapy ; Surgical Wound Dehiscence/diagnosis/*therapy ; Surgical Wound Infection/diagnosis/therapy ; Varicose Ulcer/diagnosis/*therapy ; Wound Infection/diagnosis/*therapy ; Wounds and Injuries/therapy ; }, abstract = {The potential impact of biofilm on healing in acute and chronic wounds is one of the most controversial current issues in wound care. A significant amount of laboratory-based research has been carried out on this topic, however, in 2013 the European Wound Management Association (EWMA) pointed out the lack of guidance for managing biofilms in clinical practice and solicited the need for guidelines and further clinical research. In response to this challenge, the Italian Nursing Wound Healing Society (AISLeC) initiated a project which aimed to achieve consensus among a multidisciplinary and multiprofessional international panel of experts to identify what could be considered part of 'good clinical practice' with respect to the recognition and management of biofilms in acute and chronic wounds. The group followed a systematic approach, developed by the GRADE working group, to define relevant questions and clinical recommendations raised in clinical practice. An independent librarian retrieved and screened approximately 2000 pertinent published papers to produce tables of levels of evidence. After a smaller focus group had a multistep structured discussion, and a formal voting process had been completed, ten therapeutic interventions were identified as being strongly recommendable for clinical practice, while another four recommendations were graded as being 'weak'. The panel subsequently formulated a preliminary statement (although with a weak grade of agreement): 'provided that other causes that prevent optimal wound healing have been ruled out, chronic wounds are chronically infected'. All members of the panel agreed that there is a paucity of reliable, well-conducted clinical trials which have produced clear evidence related to the effects of biofilm presence. In the meantime it was agreed that expert-based guidelines were needed to be developed for the recognition and management of biofilms in wounds and for the best design of future clinical trials. This is a fundamental and urgent task for both laboratory-based scientists and clinicians.}, } @article {pmid27285813, year = {2016}, author = {Mamone, L and Ferreyra, DD and Gándara, L and Di Venosa, G and Vallecorsa, P and Sáenz, D and Calvo, G and Batlle, A and Buzzola, F and Durantini, EN and Casas, A}, title = {Photodynamic inactivation of planktonic and biofilm growing bacteria mediated by a meso-substituted porphyrin bearing four basic amino groups.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {161}, number = {}, pages = {222-229}, doi = {10.1016/j.jphotobiol.2016.05.026}, pmid = {27285813}, issn = {1873-2682}, mesh = {Biofilms/*drug effects/radiation effects ; Light ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Photosensitizing Agents/chemistry/*pharmacology ; Porphyrins/chemistry/*pharmacology ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; }, } @article {pmid27282307, year = {2017}, author = {Ortega-Peña, S and Hidalgo-González, C and Robson, MC and Krötzsch, E}, title = {In vitro microbicidal, anti-biofilm and cytotoxic effects of different commercial antiseptics.}, journal = {International wound journal}, volume = {14}, number = {3}, pages = {470-479}, pmid = {27282307}, issn = {1742-481X}, mesh = {Acinetobacter baumannii/drug effects ; Anti-Infective Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Fibroblasts/*drug effects ; Gram-Positive Bacteria/*drug effects ; Humans ; In Vitro Techniques ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; Wound Healing/*drug effects ; Wounds and Injuries/*drug therapy ; }, abstract = {Topical antiseptics are widely used for wound treatment, with the goal of disrupting biofilm capacity. We analysed the effectiveness of a variety of antiseptics to inhibit various stages of biofilm formation and to remove biofilms in vitro as well as the agents' cytotoxic effects on fibroblasts. We found that the chlorine-releasing agents exhibited immediate anti-biofilm effects in the short term, with lesser cytotoxicity than agents prepared from more stable compounds, such as biguanide or modified diallyl disulfide-oxide, which, conversely, have better long-term effectiveness. Among the examined organisms, Gram-positive bacteria and Candida albicans were the most sensitive to the antiseptics, whereas Pseudomonas aeruginosa and Acinetobacter baumannii were relatively resistant to them. Formulations whose mechanisms of action involve the release of chemically active chlorine were more effective when administered in solution than the gel form, likely because of the stability of the active ingredients during or after preparation of the formula. Interestingly, hypochlorous acid and some superoxidation solutions were effective in preventing biofilm formation within a short time period and showed virtually no toxicity. Our study indicates that most antiseptics remain effective long enough to prevent biofilm formation; thus, even brief application of an antiseptic agent during initial wound treatment can lead to better wound management outcomes.}, } @article {pmid27279710, year = {2016}, author = {de Sousa, MB and Júnior, JO and Barbosa, WL and da Silva Valério, E and da Mata Lima, A and de Araújo, MH and Muzitano, MF and Nakamura, CV and de Mello, JC and Teixeira, FM}, title = {Pyrostegia venusta (Ker Gawl.) Miers Crude Extract and Fractions: Prevention of Dental Biofilm Formation and Immunomodulatory Capacity.}, journal = {Pharmacognosy magazine}, volume = {12}, number = {Suppl 2}, pages = {S218-22}, pmid = {27279710}, issn = {0973-1296}, abstract = {BACKGROUND: Caries and periodontal diseases remain as important diseases in the Brazilian population. One important pathogen associated with this situation is Streptococcus mutans and other important factor is this pathogen's ability to adhere firmly to the tooth surface leading to dental biofilm formation and caries development.

OBJECTIVES: Determine the antibacterial and other biological activities of P. venusta related to its potential to be used in the treatment of caries and periodontal disease.

METHODS: The growth inhibition by P. venusta of Streptococcus mutans, S. mitis, S. oralis and Candida albicans was determined using the broth microdilution method. In addition, the effect of the samples in adherence and reducing production of acids by S. mutans, and germ-tube formation of C. albicans was analysed. The Nitric Oxide (NO) production and cytotoxicity of P. venusta to peripheral blood mononuclear cells (PBMC) and RAW 264.7 Cell Line Murine Macrophage from Blood were assessed.

RESULTS: The crude extract (CE) and ethyl-acetate (AF) and n-butanol (BF) fractions showed antibacterial activity. The ethyl-acetate (AF) fraction showed the highest inhibition percentage against the adherence of S. mutans and C. albicans cells without budding, beyond NO production inhibition. There was not any cytotoxicity in the murine macrophages RAW 264.7 cells.

CONCLUSION: Our results suggest that P. venusta presents potential to be used as a preliminary source of compounds that can provide helpful activity when used in prophylaxis or treatment of caries or periodontal disease.

SUMMARY: Biological activities of Pyrostegia venusta and its potential for use in formulations for the prevention of oral diseases. Abbreviations used: NO: Nitric oxide, PBMC: Peripheral blood mononuclear cells, CE: Crude extract, AF: Ethyl-acetate fraction, BF: n-butanol fraction, HF: Hexane fraction, WF: Water fraction, MIC: Minimum inhibitory concentration, MBC: Minimum bactericidal concentration, ATCC: American Type Culture Collection, CFU: Colony-forming units, BHI: Brain heart infusion, RPMI: Roswell Park Memorial Institute, MOPS: 3-(N-morpholino)propanesulfonic acid, DMEM: Dulbecco's modified Eagle's médium, LPS: Lipopolysacharide, MTT: 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide, OD: Optical density, AC: Acteoside.}, } @article {pmid27278805, year = {2016}, author = {Gomez, GF and Huang, R and MacPherson, M and Ferreira Zandona, AG and Gregory, RL}, title = {Photo Inactivation of Streptococcus mutans Biofilm by Violet-Blue light.}, journal = {Current microbiology}, volume = {73}, number = {3}, pages = {426-433}, pmid = {27278805}, issn = {1432-0991}, mesh = {Biofilms/*radiation effects ; Light ; Streptococcus mutans/genetics/growth & development/*physiology/*radiation effects ; }, abstract = {Among various preventive approaches, non-invasive phototherapy/photodynamic therapy is one of the methods used to control oral biofilm. Studies indicate that light at specific wavelengths has a potent antibacterial effect. The objective of this study was to determine the effectiveness of violet-blue light at 380-440 nm to inhibit biofilm formation of Streptococcus mutans or kill S. mutans. S. mutans UA159 biofilm cells were grown for 12-16 h in 96-well flat-bottom microtiter plates using tryptic soy broth (TSB) or TSB with 1 % sucrose (TSBS). Biofilm was irradiated with violet-blue light for 5 min. After exposure, plates were re-incubated at 37 °C for either 2 or 6 h to allow the bacteria to recover. A crystal violet biofilm assay was used to determine relative densities of the biofilm cells grown in TSB, but not in TSBS, exposed to violet-blue light. The results indicated a statistically significant (P < 0.05) decrease compared to the non-treated groups after the 2 or 6 h recovery period. Growth rates of planktonic and biofilm cells indicated a significant reduction in the growth rate of the violet-blue light-treated groups grown in TSB and TSBS. Biofilm viability assays confirmed a statistically significant difference between violet-blue light-treated and non-treated groups in TSB and TSBS. Visible violet-blue light of the electromagnetic spectrum has the ability to inhibit S. mutans growth and reduce the formation of S. mutans biofilm. This in vitro study demonstrated that violet-blue light has the capacity to inhibit S. mutans biofilm formation. Potential clinical applications of light therapy in the future remain bright in preventing the development and progression of dental caries.}, } @article {pmid27275608, year = {2016}, author = {Yang, S and Liao, Y and Cong, L and Lu, X and Yang, R}, title = {In Vitro Interactions between Non-Steroidal Anti-Inflammatory Drugs and Antifungal Agents against Planktonic and Biofilm Forms of Trichosporon asahii.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0157047}, pmid = {27275608}, issn = {1932-6203}, mesh = {Anti-Inflammatory Agents, Non-Steroidal/agonists/*pharmacology ; Antifungal Agents/*pharmacokinetics ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Humans ; Plankton/physiology ; Trichosporon/*physiology ; Trichosporonosis/drug therapy ; }, abstract = {Increasing drug resistance has brought enormous challenges to the management of Trichosporon spp. infections. The in vitro antifungal activities of non-steroidal anti-inflammatory drugs (NSAIDs) against Candida spp. and Cryptococcus spp. were recently discovered. In the present study, the in vitro interactions between three NSAIDs (aspirin, ibuprofen and diclofenac sodium) and commonly used antifungal agents (fluconazole, itraconazole, voriconazole, caspofungin and amphotericin B) against planktonic and biofilm cells of T. asahii were evaluated using the checkerboard microdilution method. The spectrophotometric method and the XTT reduction assay were used to generate data on biofilm cells. The fractional inhibitory concentration index (FICI) and the ΔE model were compared to interpret drug interactions. Using the FICI, the highest percentages of synergistic effects against planktonic cells (86.67%) and biofilm cells (73.33%) were found for amphotericin B/ibuprofen, and caspofungin/ibuprofen showed appreciable percentages (73.33% for planktonic form and 60.00% for biofilm) as well. We did not observe antagonism. The ΔE model gave consistent results with FICI (86.67%). Our findings suggest that amphotericin B/ibuprofen and caspofungin/ibuprofen combinations have potential effects against T. asahii. Further in vivo and animal studies to investigate associated mechanisms need to be conducted.}, } @article {pmid27275603, year = {2016}, author = {Cai, JN and Jung, JE and Dang, MH and Kim, MA and Yi, HK and Jeon, JG}, title = {Functional Relationship between Sucrose and a Cariogenic Biofilm Formation.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0157184}, pmid = {27275603}, issn = {1932-6203}, mesh = {Bacterial Adhesion/*drug effects/physiology ; Biofilms/drug effects/*growth & development ; Dental Caries/*microbiology ; Dose-Response Relationship, Drug ; Polysaccharides, Bacterial/biosynthesis ; Streptococcus mutans/*physiology ; Sucrose/*pharmacology ; }, abstract = {Sucrose is an important dietary factor in cariogenic biofilm formation and subsequent initiation of dental caries. This study investigated the functional relationships between sucrose concentration and Streptococcus mutans adherence and biofilm formation. Changes in morphological characteristics of the biofilms with increasing sucrose concentration were also evaluated. S. mutans biofilms were formed on saliva-coated hydroxyapatite discs in culture medium containing 0, 0.05, 0.1, 0.5, 1, 2, 5, 10, 20, or 40% (w/v) sucrose. The adherence (in 4-hour biofilms) and biofilm composition (in 46-hour biofilms) of the biofilms were analyzed using microbiological, biochemical, laser scanning confocal fluorescence microscopic, and scanning electron microscopic methods. To determine the relationships, 2nd order polynomial curve fitting was performed. In this study, the influence of sucrose on bacterial adhesion, biofilm composition (dry weight, bacterial counts, and water-insoluble extracellular polysaccharide (EPS) content), and acidogenicity followed a 2nd order polynomial curve with concentration dependence, and the maximum effective concentrations (MECs) of sucrose ranged from 0.45 to 2.4%. The bacterial and EPS bio-volume and thickness in the biofilms also gradually increased and then decreased as sucrose concentration increased. Furthermore, the size and shape of the micro-colonies of the biofilms depended on the sucrose concentration. Around the MECs, the micro-colonies were bigger and more homogeneous than those at 0 and 40%, and were surrounded by enough EPSs to support their structure. These results suggest that the relationship between sucrose concentration and cariogenic biofilm formation in the oral cavity could be described by a functional relationship.}, } @article {pmid27274688, year = {2016}, author = {Fowler, AC and Kyrke-Smith, TM and Winstanley, HF}, title = {The development of biofilm architecture.}, journal = {Proceedings. Mathematical, physical, and engineering sciences}, volume = {472}, number = {2188}, pages = {20150798}, pmid = {27274688}, issn = {1364-5021}, abstract = {We extend the one-dimensional polymer solution theory of bacterial biofilm growth described by Winstanley et al. (2011 Proc. R. Soc. A467, 1449-1467 (doi:10.1098/rspa.2010.0327)) to deal with the problem of the growth of a patch of biofilm in more than one lateral dimension. The extension is non-trivial, as it requires consideration of the rheology of the polymer phase. We use a novel asymptotic technique to reduce the model to a free-boundary problem governed by the equations of Stokes flow with non-standard boundary conditions. We then consider the stability of laterally uniform biofilm growth, and show that the model predicts spatial instability; this is confirmed by a direct numerical solution of the governing equations. The instability results in cusp formation at the biofilm surface and provides an explanation for the common observation of patterned biofilm architectures.}, } @article {pmid27274079, year = {2016}, author = {Sakhtah, H and Koyama, L and Zhang, Y and Morales, DK and Fields, BL and Price-Whelan, A and Hogan, DA and Shepard, K and Dietrich, LE}, title = {The Pseudomonas aeruginosa efflux pump MexGHI-OpmD transports a natural phenazine that controls gene expression and biofilm development.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {25}, pages = {E3538-47}, pmid = {27274079}, issn = {1091-6490}, support = {R01 AI091702/AI/NIAID NIH HHS/United States ; R01 AI103369/AI/NIAID NIH HHS/United States ; R01 GM108492/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/*physiology ; Biofilms/*growth & development ; Carrier Proteins/*physiology ; Gene Expression Regulation, Bacterial/*physiology ; Phenazines/*metabolism ; Pseudomonas aeruginosa/*metabolism ; }, abstract = {Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples. Here, we apply electrochemical methods to directly detect 5-Me-PCA and find that it is transported by MexGHI-OpmD in P. aeruginosa strain PA14 planktonic and biofilm cells. We also show that 5-Me-PCA is sufficient to fully induce MexGHI-OpmD expression and that it is required for wild-type colony biofilm morphogenesis. These physiological effects are consistent with the high redox potential of 5-Me-PCA, which distinguishes it from other well-studied P. aeruginosa phenazines. Our observations highlight the importance of this compound, which was previously overlooked due to the challenges associated with its detection, in the context of P. aeruginosa gene expression and multicellular behavior. This study constitutes a unique demonstration of efflux-based self-resistance, controlled by a simple circuit, in a Gram-negative pathogen.}, } @article {pmid27274032, year = {2016}, author = {Yawata, Y and Nguyen, J and Stocker, R and Rusconi, R}, title = {Microfluidic Studies of Biofilm Formation in Dynamic Environments.}, journal = {Journal of bacteriology}, volume = {198}, number = {19}, pages = {2589-2595}, pmid = {27274032}, issn = {1098-5530}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Environment ; *Microfluidic Analytical Techniques ; Time Factors ; }, abstract = {The advent of microscale technologies, such as microfluidics, has revolutionized many areas of biology yet has only recently begun to impact the field of bacterial biofilms. By enabling accurate control and manipulation of physical and chemical conditions, these new microscale approaches afford the ability to combine important features of natural and artificial microbial habitats, such as fluid flow and ephemeral nutrient sources, with an unprecedented level of flexibility and quantification. Here, we review selected case studies to exemplify this potential, discuss limitations, and suggest that this approach opens new vistas into biofilm research over traditional setups, allowing us to expand our understanding of the formation and consequences of biofilms in a broad range of environments and applications.}, } @article {pmid27274027, year = {2016}, author = {Anderson, MT and Byerly, L and Apicella, MA and Seifert, HS}, title = {Seminal Plasma Promotes Neisseria gonorrhoeae Aggregation and Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {198}, number = {16}, pages = {2228-2235}, pmid = {27274027}, issn = {1098-5530}, support = {R21 AI109320/AI/NIAID NIH HHS/United States ; R37 AI033493/AI/NIAID NIH HHS/United States ; R56 AI114821/AI/NIAID NIH HHS/United States ; }, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Humans ; Neisseria gonorrhoeae/*physiology ; *Semen ; }, abstract = {UNLABELLED: Neisseria gonorrhoeae causes the human-specific disease gonorrhea and is transmitted from person to person primarily via sexual contact. During transmission, N. gonorrhoeae is often exposed to seminal fluid and must adapt to this change in environment. Previous work demonstrated that seminal fluid facilitates N. gonorrhoeae motility and alters epithelial cell interactions. In this study, exposure to seminal fluid was found to decrease surface adherence of gonococci in a manner that was independent of Opa adhesin proteins or type IV pilus retraction. Semen was also shown to cause dispersal of bacteria that had previously established surface adherence. Although surface adherence decreased, interbacterial interactions were increased by seminal plasma both in long-term static culture and on a cell-to-cell basis over shorter time periods. The result of increased bacterium-bacterium interactions resulted in the formation of microcolonies, an important step in the N. gonorrhoeae infectious process. Seminal fluid also facilitated increased bacterial aggregation in the form of shear-resistant three-dimensional biofilms. These results emphasize the importance of the gonococcal response to the influx of seminal fluid within the genital niche. Further characterization of the N. gonorrhoeae response to semen will advance our understanding of the mechanisms behind the establishment of infection in naive hosts and the process of transmission.

IMPORTANCE: N. gonorrhoeae is the causative agent of the globally prevalent sexually transmitted infection gonorrhea. An understudied aspect of this human-adapted pathogen is the change in bacterial physiology that occurs during sexual transmission. N. gonorrhoeae encounters semen when transmitted from host to host, and it is known that, when N. gonorrhoeae is exposed to seminal fluid, alterations in bacterial motility and type IV pilus arrangement occur. This work extends our previous observations on this modulation of gonococcal physiology by seminal fluid and demonstrates that seminal plasma decreases surface adherence, promotes interbacterial interactions, and enhances biofilm formation.}, } @article {pmid27273460, year = {2016}, author = {Liu, Y and Sun, J and Peng, L and Wang, D and Dai, X and Ni, BJ}, title = {Assessment of Heterotrophic Growth Supported by Soluble Microbial Products in Anammox Biofilm using Multidimensional Modeling.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27576}, pmid = {27273460}, issn = {2045-2322}, mesh = {Ammonium Compounds/*metabolism ; Anaerobiosis/*physiology ; Autotrophic Processes/*physiology ; Bacteria/*growth & development/metabolism ; Biofilms/*growth & development ; Biomass ; Computer Simulation ; Heterotrophic Processes/*physiology ; Kinetics ; Microbial Consortia/physiology ; Models, Chemical ; Oxidation-Reduction ; }, abstract = {Anaerobic ammonium oxidation (anammox) is known to autotrophically convert ammonium to dinitrogen gas with nitrite as the electron acceptor, but little is known about their released microbial products and how these are relative to heterotrophic growth in anammox system. In this work, we applied a mathematical model to assess the heterotrophic growth supported by three key microbial products produced by bacteria in anammox biofilm (utilization associated products (UAP), biomass associated products (BAP), and decay released substrate). Both One-dimensional and two-dimensional numerical biofilm models were developed to describe the development of anammox biofilm as a function of the multiple bacteria-substrate interactions. Model simulations show that UAP of anammox is the main organic carbon source for heterotrophs. Heterotrophs are mainly dominant at the surface of the anammox biofilm with small fraction inside the biofilm. 1-D model is sufficient to describe the main substrate concentrations/fluxes within the anammox biofilm, while the 2-D model can give a more detailed biomass distribution. The heterotrophic growth on UAP is mainly present at the outside of anammox biofilm, their growth on BAP (HetB) are present throughout the biofilm, while the growth on decay released substrate (HetD) is mainly located in the inner layers of the biofilm.}, } @article {pmid27273453, year = {2016}, author = {Kundukad, B and Seviour, T and Liang, Y and Rice, SA and Kjelleberg, S and Doyle, PS}, title = {Mechanical properties of the superficial biofilm layer determine the architecture of biofilms.}, journal = {Soft matter}, volume = {12}, number = {26}, pages = {5718-5726}, doi = {10.1039/c6sm00687f}, pmid = {27273453}, issn = {1744-6848}, mesh = {Bacteria/*growth & development ; *Biofilms ; *Elastic Modulus ; Extracellular Matrix/*physiology ; Microscopy, Atomic Force ; }, abstract = {Cells in biofilms sense and interact with their environment through the extracellular matrix. The physicochemical properties of the matrix, particularly at the biofilm-environment interface, determine how cells respond to changing conditions. In this study we describe the application of atomic force microscopy and confocal imaging to probe in situ the mechanical properties of these interfacial regions and to elucidate how key matrix components can contribute to the physical sensing by the cells. We describe how the Young's modulus of microcolonies differs according to the size and morphology of microcolonies, as well as the flow rate. The Young's modulus increased as a function of microcolony diameter, which was correlated with the production of the polysaccharide Psl at later stages of maturation for hemispherical or mushroom shaped microcolonies. The Young's modulus of the periphery of the biofilm colony was however independent of the hydrodynamic shear. The morphology of the microcolonies also influenced interfacial or peripheral stiffness. Microcolonies with a diffuse morphology had a lower Young's modulus than isolated, circular ones and this phenomenon was due to a deficiency of Psl. In this way, changes in the specific polysaccharide components imbue the biofilm with distinct physical properties that may modulate the way in which bacteria perceive or respond to their environment. Further, the physical properties of the polysaccharides are closely linked to the specific architectures formed by the developing biofilm.}, } @article {pmid27272091, year = {2016}, author = {Eilers, H and Alexeyev, OA}, title = {Effect of GT-Peptide 10 and Triethyl Citrate on <em>P. acnes</em> Biofilm Formation, Viability, and Dispersion.}, journal = {Journal of drugs in dermatology : JDD}, volume = {15}, number = {6}, pages = {778-781}, pmid = {27272091}, issn = {1545-9616}, mesh = {Acne Vulgaris/drug therapy ; Biofilms/*drug effects/growth & development ; Citrates/*administration & dosage ; Dose-Response Relationship, Drug ; Drug Therapy, Combination ; Humans ; Microbial Sensitivity Tests/methods ; Peptide Fragments/*administration & dosage ; Propionibacterium acnes/*drug effects/physiology ; Treatment Outcome ; }, abstract = {BACKGROUND: P. acnes biofilms are emerging topics in acne vulgaris pathogenesis and may be responsible for antibiotic tolerance.


OBJECTIVE: To investigate the efficacy of GT peptide 10 either alone or in combination with triethyl citrate (TEC) in in vitro model of P. acnes biofilm.


METHODS: Six-day-old P. acnes biofilms were treated with various concentrations of these substances and biofilm dispersion and cell viability were monitored.


RESULTS: A 24-hour exposure of preformed biofilms to a combination of GT peptide 10/TEC led to killing of up to 92% of bacterial cells inside the biofilm. Neither the single substance nor the combination of both substances affected the biofilm integrity or resulted in biofilm dispersal.


CONCLUSIONS: A combination of GT peptide 10/TEC shows antibacterial effects in in vitro model of P. acnes biofilm.

J Drugs Dermatol. 2016;15(6):778-781.}, } @article {pmid27272073, year = {2016}, author = {Bernhardt, MJ and Myntti, MF}, title = {Topical Treatment With an Agent Disruptive to <em>P. acnes</em> Biofilm Provides Positive Therapeutic Response: Results of a Randomized Clinical Trial.}, journal = {Journal of drugs in dermatology : JDD}, volume = {15}, number = {6}, pages = {677-683}, pmid = {27272073}, issn = {1545-9616}, mesh = {Acne Vulgaris/diagnosis/*drug therapy/*psychology ; Administration, Topical ; Adolescent ; Adult ; Anti-Bacterial Agents/*administration & dosage ; Biofilms/*drug effects ; Child ; Double-Blind Method ; Female ; Follow-Up Studies ; Gels ; Humans ; Male ; Propionibacterium acnes/*drug effects/physiology ; Prospective Studies ; Quality of Life/*psychology ; Salicylic Acid/administration & dosage ; Sebum/drug effects/physiology ; Surveys and Questionnaires ; Treatment Outcome ; Young Adult ; }, abstract = {The traditional disease model of acne has been one of follicular plugging due to 'sticky epithelial cells' associated with increased sebum production with deep follicular anaerobic conditions favoring P. acnes- generated inflammation. P. acnes biofilms have been found more frequently in patients with acne than controls. Biofilms are genetically coded to create adhesion to the pilosebaceous unit followed by production of a mucopolysaccharide coating capable of binding to lipid surfaces. Traditional therapies for acne have involved mixtures of oral and topical antibiotics admixed with topical keratolytics and retinoids, which are aimed at traditional bacterial reduction as well as downregulating the inflammatory cascade. These approaches are limited by side effect and compliance/tolerability issues. As the P. acnes biofilm may, in fact, be the instigator of this process, we studied the use of a topical agent designed to reduce the P. acnes biofilm to see if reducing the biofilm would be therapeutically efficacious. We present data of a proprietary topical non-prescription agent with a novel pharmaco mechanism designed to attack the biofilm produced by P. acnes. Our data shows a decrease of inflammatory lesions by 44% and non-inflammatory lesions by 32% after 12 weeks and also provided for a meaningful improvement in the quality of life of the patients in the study. These improvements were achieved with a product that was not associated with burning, chafing, irritation, or erythema, which can be seen with topical treatments. It is apparent from this study that by addressing the biofilm which protects the P. acnes bacteria through the use of the Acne Gel, the incidence of acne symptoms can be greatly reduced, while having no negative impacts on the patients' skin (ClinicalTrials.gov registry number NCT02404285).

J Drugs Dermatol. 2016;15(6):677-683.}, } @article {pmid27271597, year = {2016}, author = {Washio, J and Takahashi, N}, title = {Metabolomic Studies of Oral Biofilm, Oral Cancer, and Beyond.}, journal = {International journal of molecular sciences}, volume = {17}, number = {6}, pages = {}, pmid = {27271597}, issn = {1422-0067}, mesh = {*Biofilms ; Electrophoresis, Capillary ; Humans ; Metabolome ; *Metabolomics/methods ; *Microbiota ; Mouth/*microbiology ; Mouth Neoplasms/*etiology/*metabolism ; Research ; Saliva/metabolism/microbiology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {Oral diseases are known to be closely associated with oral biofilm metabolism, while cancer tissue is reported to possess specific metabolism such as the 'Warburg effect'. Metabolomics might be a useful method for clarifying the whole metabolic systems that operate in oral biofilm and oral cancer, however, technical limitations have hampered such research. Fortunately, metabolomics techniques have developed rapidly in the past decade, which has helped to solve these difficulties. In vivo metabolomic analyses of the oral biofilm have produced various findings. Some of these findings agreed with the in vitro results obtained in conventional metabolic studies using representative oral bacteria, while others differed markedly from them. Metabolomic analyses of oral cancer tissue not only revealed differences between metabolomic profiles of cancer and normal tissue, but have also suggested a specific metabolic system operates in oral cancer tissue. Saliva contains a variety of metabolites, some of which might be associated with oral or systemic disease; therefore, metabolomics analysis of saliva could be useful for identifying disease-specific biomarkers. Metabolomic analyses of the oral biofilm, oral cancer, and saliva could contribute to the development of accurate diagnostic, techniques, safe and effective treatments, and preventive strategies for oral and systemic diseases.}, } @article {pmid27271534, year = {2016}, author = {Thies, S and Rausch, SC and Kovacic, F and Schmidt-Thaler, A and Wilhelm, S and Rosenau, F and Daniel, R and Streit, W and Pietruszka, J and Jaeger, KE}, title = {Metagenomic discovery of novel enzymes and biosurfactants in a slaughterhouse biofilm microbial community.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27035}, pmid = {27271534}, issn = {2045-2322}, mesh = {Abattoirs ; Amino Acid Sequence ; Anti-Bacterial Agents/biosynthesis/chemistry/pharmacology ; Bacterial Proteins/genetics ; *Biofilms ; Biosynthetic Pathways ; *Environmental Microbiology ; Escherichia coli/genetics ; Flavobacterium/genetics ; Genes, Bacterial ; Metagenome ; Microbial Consortia/*genetics ; Microbial Sensitivity Tests ; Open Reading Frames ; Phylogeny ; Sequence Analysis, DNA ; Surface-Active Agents/*chemistry/metabolism/pharmacology ; }, abstract = {DNA derived from environmental samples is a rich source of novel bioactive molecules. The choice of the habitat to be sampled predefines the properties of the biomolecules to be discovered due to the physiological adaptation of the microbial community to the prevailing environmental conditions. We have constructed a metagenomic library in Escherichia coli DH10b with environmental DNA (eDNA) isolated from the microbial community of a slaughterhouse drain biofilm consisting mainly of species from the family Flavobacteriaceae. By functional screening of this library we have identified several lipases, proteases and two clones (SA343 and SA354) with biosurfactant and hemolytic activities. Sequence analysis of the respective eDNA fragments and subsequent structure homology modelling identified genes encoding putative N-acyl amino acid synthases with a unique two-domain organisation. The produced biosurfactants were identified by NMR spectroscopy as N-acyltyrosines with N-myristoyltyrosine as the predominant species. Critical micelle concentration and reduction of surface tension were similar to those of chemically synthesised N-myristoyltyrosine. Furthermore, we showed that the newly isolated N-acyltyrosines exhibit antibiotic activity against various bacteria. This is the first report describing the successful application of functional high-throughput screening assays for the identification of biosurfactant producing clones within a metagenomic library.}, } @article {pmid27271216, year = {2016}, author = {Zhang, SK and Song, JW and Gong, F and Li, SB and Chang, HY and Xie, HM and Gao, HW and Tan, YX and Ji, SP}, title = {Design of an α-helical antimicrobial peptide with improved cell-selective and potent anti-biofilm activity.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27394}, pmid = {27271216}, issn = {2045-2322}, mesh = {Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Circular Dichroism ; Peptides/chemistry/*pharmacology ; Protein Structure, Secondary ; }, abstract = {AR-23 is a melittin-related peptide with 23 residues. Like melittin, its high α-helical amphipathic structure results in strong bactericidal activity and cytotoxicity. In this study, a series of AR-23 analogues with low amphipathicity were designed by substitution of Ala1, Ala8 and Ile17 with positively charged residues (Arg or Lys) to study the effect of positively charged residue distribution on the biological viability of the antimicrobial peptide. Substitution of Ile17 on the nonpolar face with positively charged Lys dramatically altered the hydrophobicity, amphipathicity, helicity and the membrane-penetrating activity against human cells as well as the haemolytic activity of the peptide. However, substitution on the polar face only slightly affected the peptide biophysical properties and biological activity. The results indicate that the position rather than the number of positively charged residue affects the biophysical properties and selectivity of the peptide. Of all the analogues, A(A1R, A8R, I17K), a peptide with Ala1-Arg, Ala8-Arg and Ile17-Lys substitutions, exhibited similar bactericidal activity and anti-biofilm activity to AR-23 but had much lower haemolytic activity and cytotoxicity against mammalian cells compared with AR-23. Therefore, the findings reported here provide a rationalization for peptide design and optimization, which will be useful for the future development of antimicrobial agents.}, } @article {pmid27270283, year = {2016}, author = {Knippenberg, B and Page-Sharp, M and Salman, S and Clark, B and Dyer, J and Batty, KT and Davis, TM and Manning, L}, title = {Validation and Application of a Dried Blood Spot Assay for Biofilm-Active Antibiotics Commonly Used for Treatment of Prosthetic Implant Infections.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {8}, pages = {4940-4955}, pmid = {27270283}, issn = {1098-6596}, mesh = {Adult ; Anti-Bacterial Agents/*therapeutic use ; Biofilms/*drug effects ; Biological Assay/*methods ; Chromatography, Liquid/methods ; Ciprofloxacin/therapeutic use ; Dried Blood Spot Testing/*methods ; Drug Monitoring/methods ; Female ; Fusidic Acid/therapeutic use ; Hematocrit/methods ; Humans ; Male ; Middle Aged ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/*drug therapy/*microbiology ; Reproducibility of Results ; Rifampin/therapeutic use ; Tandem Mass Spectrometry/methods ; }, abstract = {Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK)/pharmacodynamic (PD) studies in situations where venous blood sampling is logistically difficult. We sought to develop, validate, and apply a DBS assay for rifampin (RIF), fusidic acid (FUS), and ciprofloxacin (CIP). These antibiotics are considered active against organisms in biofilms and are therefore commonly used for the treatment of infections associated with prosthetic implants. A liquid chromatography-mass spectroscopy DBS assay was developed and validated, including red cell partitioning and thermal stability for each drug and the rifampin metabolite desacetyl rifampin (Des-RIF). Plasma and DBS concentrations in 10 healthy adults were compared, and the concentration-time profiles were incorporated into population PK models. The limits of quantification for RIF, Des-RIF, CIP, and FUS in DBS were 15 μg/liter, 14 μg/liter, 25 μg/liter, and 153 μg/liter, respectively. Adjusting for hematocrit, red cell partitioning, and relative recovery, DBS-predicted plasma concentrations were comparable to measured plasma concentrations for each antibiotic (r > 0.95; P < 0.0001), and Bland-Altman plots showed no significant bias. The final population PK estimates of clearance, volume of distribution, and time above threshold MICs for measured and DBS-predicted plasma concentrations were comparable. These drugs were stable in DBSs for at least 10 days at room temperature and 1 month at 4°C. The present DBS antibiotic assays are robust and can be used as surrogates for plasma concentrations to provide valid PK and PK/PD data in a variety of clinical situations, including therapeutic drug monitoring or studies of implant infections.}, } @article {pmid27268931, year = {2016}, author = {Pande, VV and McWhorter, AR and Chousalkar, KK}, title = {Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces.}, journal = {Biofouling}, volume = {32}, number = {7}, pages = {699-710}, doi = {10.1080/08927014.2016.1191068}, pmid = {27268931}, issn = {1029-2454}, mesh = {Animals ; Biofilms/*growth & development ; Egg Shell/*microbiology/ultrastructure ; Farms/*standards ; Microscopy, Electron, Scanning ; Models, Biological ; Salmonella enterica/*isolation & purification/physiology ; Temperature ; }, abstract = {This study examined the eggshell biofilm forming ability of Salmonella enterica isolates recovered from egg farms. Multicellular behaviour and biofilm production were examined at 22 and 37°C by Congo red morphology and the crystal violet staining assay. The results indicated that the biofilm forming behaviour of Salmonella isolates was dependent on temperature and associated with serovars. Significantly greater biofilm production was observed at 22°C compared with 37°C. The number of viable biofilm cells attached to eggshells after incubation for 48 h at 22°C was significantly influenced by serovar. Scanning electron microscopic examination revealed firm attachment of bacterial cells to the eggshell surface. The relative expression of csgD and adrA gene was significantly higher in eggshell biofilm cells of S. Mbandaka and S. Oranienburg. These findings demonstrate that Salmonella isolates are capable of forming biofilm on the eggshell surface and that this behaviour is influenced by temperature and serovar.}, } @article {pmid27268722, year = {2016}, author = {Oh, E and Kim, JC and Jeon, B}, title = {Stimulation of biofilm formation by oxidative stress in Campylobacter jejuni under aerobic conditions.}, journal = {Virulence}, volume = {7}, number = {7}, pages = {846-851}, pmid = {27268722}, issn = {2150-5608}, mesh = {Aerobiosis ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Campylobacter jejuni/genetics/*physiology ; *Oxidative Stress ; }, } @article {pmid27267987, year = {2016}, author = {Mhatre, E and Troszok, A and Gallegos-Monterrosa, R and Lindstädt, S and Hölscher, T and Kuipers, OP and Kovács, ÁT}, title = {The impact of manganese on biofilm development of Bacillus subtilis.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {8}, pages = {1468-1478}, doi = {10.1099/mic.0.000320}, pmid = {27267987}, issn = {1465-2080}, mesh = {Antimicrobial Cationic Peptides/biosynthesis ; Bacillus subtilis/genetics/*growth & development/*metabolism ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Manganese/*metabolism ; Signal Transduction/physiology ; Spores, Bacterial/*growth & development ; }, abstract = {Bacterial biofilms are dynamic and structurally complex communities, involving cell-to-cell interactions. In recent years, various environmental signals that induce the complex biofilm development of the Gram-positive bacterium Bacillus subtilis have been identified. These signalling molecules are often media components or molecules produced by the cells themselves, as well as those of other interacting species. The responses can also be due to depletion of certain molecules in the vicinity of the cells. Extracellular manganese (Mn2+) is essential for proper biofilm development of B. subtilis. Mn2+ is also a component of practically all laboratory biofilm-promoting media used for B. subtilis. Comparison of complex colony biofilms in the presence or absence of supplemented Mn2+ using microarray analyses revealed that genes involved in biofilm formation are indeed downregulated in the absence of Mn2+. In addition, Mn2+ also affects the transcription of several other genes involved in distinct differentiation pathways of various cellular processes. The effects of Mn2+ on other biofilm-related traits like motility, antimicrobial production, stress and sporulation were followed using fluorescent reporter strains. The global transcriptome and morphology studies highlight the importance of Mn2+ during biofilm development and provide an overview on the expressional changes in colony biofilms in B. subtilis.}, } @article {pmid27266627, year = {2016}, author = {Rosa, JP and Tibúrcio, SR and Marques, JM and Seldin, L and Coelho, RR}, title = {Streptomyces lunalinharesii 235 prevents the formation of a sulfate-reducing bacterial biofilm.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {47}, number = {3}, pages = {603-609}, pmid = {27266627}, issn = {1678-4405}, mesh = {Anti-Bacterial Agents/pharmacology ; *Antibiosis ; *Biofilms/drug effects/growth & development ; Microbial Sensitivity Tests ; *Oxidation-Reduction ; Streptomyces/drug effects/*physiology/ultrastructure ; Sulfates/*metabolism ; }, abstract = {Streptomyces lunalinharesii strain 235 produces an antimicrobial substance that is active against sulfate reducing bacteria, the major bacterial group responsible for biofilm formation and biocorrosion in petroleum reservoirs. The use of this antimicrobial substance for sulfate reducing bacteria control is therefore a promising alternative to chemical biocides. In this study the antimicrobial substance did not interfere with the biofilm stability, but the sulfate reducing bacteria biofilm formation was six-fold smaller in carbon steel coupons treated with the antimicrobial substance when compared to the untreated control. A reduction in the most probable number counts of planktonic cells of sulfate reducing bacteria was observed after treatments with the sub-minimal inhibitory concentration, minimal inhibitory concentration, and supra-minimal inhibitory concentration of the antimicrobial substance. Additionally, when the treated coupons were analyzed by scanning electron microscopy, the biofilm formation was found to be substantially reduced when the supra-minimal inhibitory concentration of the antimicrobial substance was used. The coupons used for the biofilm formation had a small weight loss after antimicrobial substance treatment, but corrosion damage was not observed by scanning electron microscopy. The absence of the dsrA gene fragment in the scraped cell suspension after treatment with the supra-minimal inhibitory concentration of the antimicrobial substance suggests that Desulfovibrio alaskensis was not able to adhere to the coupons. This is the first report on an antimicrobial substance produced by Streptomyces active against sulfate reducing bacteria biofilm formation. The application of antimicrobial substance as a potential biocide for sulfate reducing bacteria growth control could be of great interest to the petroleum industry.}, } @article {pmid27264911, year = {2016}, author = {Verma, P and Saravanan, N and Jia, B and Jeon, CO and Dharani, G and Somasundaram, ST and Kirubagaran, R}, title = {Pseudogracilibacillus marinus sp. nov., isolated from a biofilm formed in coastal seawater.}, journal = {International journal of systematic and evolutionary microbiology}, volume = {66}, number = {9}, pages = {3443-3448}, doi = {10.1099/ijsem.0.001212}, pmid = {27264911}, issn = {1466-5034}, mesh = {Bacillaceae/*classification/genetics/isolation & purification ; Bacterial Typing Techniques ; Base Composition ; *Biofilms ; DNA, Bacterial/genetics ; Diaminopimelic Acid/chemistry ; Fatty Acids/chemistry ; Genes, Bacterial ; India ; Peptidoglycan/chemistry ; Phospholipids/chemistry ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/*microbiology ; Sequence Analysis, DNA ; }, abstract = {A Gram-staining-positive, aerobic, motile, rod-shaped (0.4-0.5×2.0-4.0 µm), endospore-forming bacterium, designated strain NIOT.bflm.S4T, was isolated from biofilm formed on high-density polyethylene test coupons in coastal seawater. The strain required seawater for growth. It grew with 1.0-8.0 % (w/v) NaCl, at 4-45 °C and at pH 6.5-9.0, with optimum growth with 4.0-5.0 % (w/v) NaCl, at 30 °C and at pH 7.0-8.0. Phylogenetic analyses based on 16S rRNA and partial dnaK gene sequences showed that strain NIOT.bflm.S4T formed a phylogenetic lineage with Pseudogracilibacillus auburnensis P-207T, the only known species of the genus Pseudogracilibacillusand shared sequence identities of 96.9 and 83 %, respectively, with this strain. The identities of 16S rRNA and partial dnaK gene sequences with members of other related genera such as Gracilibacillus, Paraliobacillus, Ornithinibacillus, Oceanobacillus, Virgibacillus and Lentibacillus were ≤95 and ≤78 %, respectively. The DNA G+C content of strain NIOT.bflm.S4T was 39.1 mol%. MK-7 was found as the sole isoprenoid quinone. The major polar lipids of strain NIOT.bflm.S4T were diphosphatidylglycerol, phosphatidylethanolamine and an unknown lipid. The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. Major cellular fatty acids were anteiso-C15 : 0 (27.9 %), anteiso-C17 : 0 (18.6 %), C12 : 0 (8.7 %) and iso-C15 : 0 (6.6 %). On the basis of phenotypic, phylogenetic and chemotaxonomic results, we propose that the isolate represents a novel species of the genus Pseudogracilibacillus, for which the name Pseudogracilibacillus marinus sp. nov. is proposed. The type strain is NIOT.bflm.S4T (=KACC 18456T=MTCC 12376T=TBRC 5831T).}, } @article {pmid27263096, year = {2016}, author = {Syal, K and Maiti, K and Naresh, K and Avaji, PG and Chatterji, D and Jayaraman, N}, title = {Synthetic arabinomannan glycolipids impede mycobacterial growth, sliding motility and biofilm structure.}, journal = {Glycoconjugate journal}, volume = {33}, number = {5}, pages = {763-777}, pmid = {27263096}, issn = {1573-4986}, mesh = {Biofilms/*drug effects/growth & development ; *Glycolipids/chemical synthesis/chemistry/pharmacology ; *Mannans/chemical synthesis/chemistry/pharmacology ; Mycobacterium smegmatis/*physiology ; }, abstract = {Mycobacterium has evolved distinct cell wall and strategies such as biofilm formation, which helps it to survive in hostile conditions. We have reported previously that arabinofuranoside containing glycolipids exhibit inhibition activities against the above functions of the mycobacterial species M. smegmatis. In search for activities mediated by oligosaccharide glycolipids, we report herein the inhibitory activities of a linear and a branched pentasaccharides having arabinan and mannan moieties. In the presence of the pentasaccharide glycolipids, a significant reduction in mycobacterial growth is observed, concomitant with reductions in sliding motility and colonization through biofilm formation, at the optimal glycolipid concentrations of 50-100 μg mL(-1). Especially the biofilm coat is ruptured by ~80-85 % in the presence of glycolipids. Pentasaccharides alone without the lipidic chain show only a weak effect. The glycolipids are non-toxic, as evaluated through their effect on RBCs. Analysis of the mycolic acid profile of glycolipid treated biofilm shows that α- and epoxy mycolic acids are downregulated significantly, in comparison to glycolipid untreated biofilms. Lipidomics profile analysis through mass spectrometry further reveals profound downregulation of phosphatidylinositol mannosides, acylatedphosphoglycerols and mycolic acid family, namely, keto-, alpha- and methoxymycolic acids.}, } @article {pmid27262948, year = {2016}, author = {Czerwonka, G and Guzy, A and Kałuża, K and Grosicka, M and Dańczuk, M and Lechowicz, Ł and Gmiter, D and Kowalczyk, P and Kaca, W}, title = {The role of Proteus mirabilis cell wall features in biofilm formation.}, journal = {Archives of microbiology}, volume = {198}, number = {9}, pages = {877-884}, pmid = {27262948}, issn = {1432-072X}, mesh = {Bacterial Adhesion/*physiology ; Biofilms/*growth & development ; Cell Wall/*physiology ; Electrophoresis ; Glass ; Hydrophobic and Hydrophilic Interactions ; Proteus mirabilis/growth & development/*physiology ; }, abstract = {Biofilms formed by Proteus mirabilis strains are a serious medical problem, especially in the case of urinary tract infections. Early stages of biofilm formation, such as reversible and irreversible adhesion, are essential for bacteria to form biofilm and avoid eradication by antibiotic therapy. Adhesion to solid surfaces is a complex process where numerous factors play a role, where hydrophobic and electrostatic interactions with solid surface seem to be substantial. Cell surface hydrophobicity and electrokinetic potential of bacterial cells depend on their surface composition and structure, where lipopolysaccharide, in Gram-negative bacteria, is prevailing. Our studies focused on clinical and laboratory P. mirabilis strains, where laboratory strains have determined LPS structures. Adherence and biofilm formation tests revealed significant differences between strains adhered in early stages of biofilm formation. Amounts of formed biofilm were expressed by the absorption of crystal violet. Higher biofilm amounts were formed by the strains with more negative values of zeta potential. In contrast, high cell surface hydrophobicity correlated with low biofilm amount.}, } @article {pmid27262848, year = {2016}, author = {Mauffrey, C and Herbert, B and Young, H and Wilson, ML and Hake, M and Stahel, PF}, title = {The role of biofilm on orthopaedic implants: the "Holy Grail" of post-traumatic infection management?.}, journal = {European journal of trauma and emergency surgery : official publication of the European Trauma Society}, volume = {42}, number = {4}, pages = {411-416}, pmid = {27262848}, issn = {1863-9941}, mesh = {Anti-Bacterial Agents/*administration & dosage/*therapeutic use ; Biofilms/*drug effects/growth & development ; Humans ; Infusion Pumps, Implantable ; Orthopedics ; Polymerase Chain Reaction ; Postoperative Complications/diagnosis/*microbiology/*therapy ; Prostheses and Implants/*microbiology ; Sonication ; Surgical Wound Infection/diagnosis/microbiology/therapy ; Wounds and Injuries/microbiology/*surgery ; }, abstract = {The development of post-traumatic infection is potentially a limb threatening condition. The orthopaedic trauma literature lags behind the research performed by our arthroplasty colleagues on the topic of implant-related infections. Surgical site infections in the setting of a recent ORIF are notoriously hard to eradicate due to biofilm formation around the implant. This bacteria-friendly, dynamic, living pluri-organism structure has the ability to morph and adapt to virtually any environment with the aim to maintain the causative organism alive. The challenges are twofold: establishing an accurate diagnosis with speciation/sensitivity and eradicating the infection. Multiple strategies have been researched to improve diagnostic accuracy, to prevent biofilm formation on orthopaedic implants, to mobilize/detach or weaken the biofilm or to target specifically bacteria embedded in the biofilm. The purpose of our paper is to review the patho-physiology of this mysterious pluri-cellular structure and to summarize some of the most pertinent research performed to improve diagnostic and treatment strategies in biofilm-related infections.}, } @article {pmid27262549, year = {2016}, author = {Jo, SJ and Kwon, H and Jeong, SY and Lee, CH and Kim, TG}, title = {Comparison of microbial communities of activated sludge and membrane biofilm in 10 full-scale membrane bioreactors.}, journal = {Water research}, volume = {101}, number = {}, pages = {214-225}, doi = {10.1016/j.watres.2016.05.042}, pmid = {27262549}, issn = {1879-2448}, mesh = {*Biofilms ; Biofouling ; Bioreactors/microbiology ; Membranes, Artificial ; Sewage/*microbiology ; Waste Disposal, Fluid ; Wastewater/microbiology ; }, abstract = {Operation of membrane bioreactors (MBRs) for wastewater treatment is hampered by the membrane biofouling resulting from microbial activities. However, the knowledge of the microbial ecology of both biofilm and activated sludge in MBRs has not been sufficient. In this study, we scrutinized microbial communities of biofilm and activated sludge from 10 full-scale MBR plants. Overall, Flavobacterium, Dechloromonas and Nitrospira were abundant in order of abundance in biofilm, whereas Dechloromonas, Flavobacterium and Haliscomenobacter in activated sludge. Community structure was analyzed in either biofilm or activated sludge. Among MBRs, as expected, not only diversity of microbial community but also its composition was different from one another (p < 0.05). Between the biofilm and activated sludge, community composition made significant difference, but its diversity measures (i.e., alpha diversity, e.g., richness, diversity and evenness) did not (p > 0.05). Effects of ten environmental factors on community change were investigated using Spearman correlation. MLSS, HRT, F/M ratio and SADm explained the variation of microbial composition in the biofilm, whereas only MLSS did in the activated sludge. Microbial networks were constructed with the 10 environmental factors. The network results revealed that there were different topological characteristics between the biofilm and activated sludge networks, in which each of the 4 factors had different associations with microbial nodes. These results indicated that the different microbial associations were responsible for the variation of community composition between the biofilm and activated sludge.}, } @article {pmid27262331, year = {2016}, author = {Raut, JS and Karuppayil, SM}, title = {Phytochemicals as Inhibitors of Candida Biofilm.}, journal = {Current pharmaceutical design}, volume = {22}, number = {27}, pages = {4111-4134}, doi = {10.2174/1381612822666160601104721}, pmid = {27262331}, issn = {1873-4286}, mesh = {Animals ; Antifungal Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/growth & development ; Humans ; Microbial Sensitivity Tests ; Phytochemicals/chemistry/*pharmacology ; }, abstract = {BACKGROUND: Candida biofilm and associated infections is a serious threat to the large population of immunocompromised patients. Biofilm growth on prosthetic devices or host tissue shows reduced sensitivity to antifungal agents and persists as a reservoir of infective cells. Options for successful treatment of biofilm associated Candida infections are restricted because most of the available antifungal drugs fail to eradicate biofilms.

OBJECTIVE: Various plant actives are known to possess interesting antifungal properties. To explore and review the potential of phytochemicals as a novel strategy against Candida biofilms is the intent of present article.

METHOD: Thorough literature search is performed to identify Candida biofilm inhibitors of plant origin. An account of efficacy of selected phytochemicals is presented taking into consideration their biofilm inhibitory concentrations.

RESULTS: This review discusses biofilm formation by Candida species, their involvement in human infections, and associated drug resistance. It gives insight into the biofilm inhibitory potential of various phytochemicals. Based on the available reports including the work done in our laboratory, several plant extracts, essential oils and phytomolecules have been identified as excellent inhibitors of biofilms of C. albicans and non-albicans Candida species (NACS).

CONCLUSION: Selected phytochemicals which exhibit activities at low concentrations without displaying toxicity to host are potential therapeutic agents against biofilm associated Candida infections. In vivo testing in animal models and clinical trials in humans are required to be taken up seriously to propose few of the phytochemicals as candidate drug molecules.}, } @article {pmid27262274, year = {2016}, author = {Song, TS and Jin, Y and Bao, J and Kang, D and Xie, J}, title = {Graphene/biofilm composites for enhancement of hexavalent chromium reduction and electricity production in a biocathode microbial fuel cell.}, journal = {Journal of hazardous materials}, volume = {317}, number = {}, pages = {73-80}, doi = {10.1016/j.jhazmat.2016.05.055}, pmid = {27262274}, issn = {1873-3336}, mesh = {*Bioelectric Energy Sources/microbiology ; Biofilms/*growth & development ; Chromium/*chemistry ; Electricity ; Electrodes ; Graphite/*chemistry ; Surface Properties ; Water Pollutants, Chemical/*chemistry ; Water Purification/instrumentation/*methods ; }, abstract = {In this study, a simple method of biocathode fabrication in a Cr(VI)-reducing microbial fuel cell (MFC) is demonstrated. A self-assembling graphene was decorated onto the biocathode microbially, constructing a graphene/biofilm, in situ. The maximum power density of the MFC with a graphene biocathode is 5.7 times that of the MFC with a graphite felt biocathode. Cr(VI) reduction was also enhanced, resulting in 100% removal of Cr(VI) within 48h, at 40mg/L Cr(VI), compared with only 58.3% removal of Cr(VI) in the MFC with a graphite felt biocathode. Cyclic voltammogram analyses showed that the graphene biocathode had faster electron transfer kinetics than the graphite felt version. Energy dispersive spectrometer (EDS) and X-ray photoelectron spectra (XPS) analysis revealed a possible adsorption-reduction mechanism for Cr(VI) reduction via the graphene biocathode. This study attempts to improve the efficiency of the biocathode in the Cr(VI)-reducing MFC, and provides a useful candidate method for the treatment of Cr(VI) contaminated wastewater, under neutral conditions.}, } @article {pmid27261097, year = {2016}, author = {Kovalova, Z and Leroy, M and Kirkpatrick, MJ and Odic, E and Machala, Z}, title = {Corona discharges with water electrospray for Escherichia coli biofilm eradication on a surface.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {112}, number = {}, pages = {91-99}, doi = {10.1016/j.bioelechem.2016.05.002}, pmid = {27261097}, issn = {1878-562X}, mesh = {Biofilms/*drug effects ; Biomass ; Decontamination/*methods ; *Electricity ; Electrodes ; Escherichia coli/*drug effects/isolation & purification/*physiology ; Plasma Gases/*pharmacology ; Surface Properties ; *Water ; }, abstract = {Low-temperature plasma (cold), a new method for the decontamination of surfaces, can be an advantageous alternative to the traditional chemical methods, autoclave or dry heat. Positive and negative corona discharges in air were tested for the eradication of 48-h Escherichia coli biofilms grown on glass slides. The biofilms were treated by cold corona discharge plasma for various exposure times. Water electrospray from the high voltage electrode was applied in some experiments. Thermostatic cultivation of the biofilm, and confocal laser scanning microscopy (CLSM) of the biofilm stained with fluorescent dyes were used for biocidal efficiency quantification. Up to 5 log10 reduction of bacterial concentration in the biofilm was measured by thermostatic cultivation after exposure to both corona discharges for 15min. This decontamination efficiency was significantly enhanced by simultaneous water electrospray through the plasma. CLSM showed that the live/dead ratio after treatment remained almost constant inside the biofilm; only cells on the top layers of the biofilm were affected. DAPI fluorescence showed that biofilm thickness was reduced by about 1/3 upon exposure to the corona discharges with electrospray for 15min. The biofilm biomass loss by about 2/3 was confirmed by crystal violet assay.}, } @article {pmid27260167, year = {2016}, author = {Ulluwishewa, D and Wang, L and Pereira, C and Flynn, S and Cain, E and Stick, S and Reen, FJ and Ramsay, JP and O'Gara, F}, title = {Dissecting the regulation of bile-induced biofilm formation in Staphylococcus aureus.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {8}, pages = {1398-1406}, doi = {10.1099/mic.0.000317}, pmid = {27260167}, issn = {1465-2080}, mesh = {ATP-Binding Cassette Transporters/genetics ; Aminoglycosides/pharmacology ; Anti-Bacterial Agents/pharmacology ; Bile/*metabolism ; Biofilms/*growth & development ; Cell Wall/*metabolism ; Cystic Fibrosis/*microbiology/pathology ; DNA Transposable Elements/genetics ; Humans ; Lung/microbiology/pathology ; Microbial Sensitivity Tests ; Protein Transport/genetics ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/*growth & development ; Teichoic Acids/biosynthesis/*metabolism ; }, abstract = {Aspiration of bile into the cystic fibrosis (CF) lung has emerged as a prognostic factor for reduced microbial lung biodiversity and the establishment of often fatal, chronic pathogen infections. Staphylococcus aureus is one of the earliest pathogens detected in the lungs of children with CF, and once established as a chronic infection, strategies for its eradication become limited. Several lung pathogens are stimulated to produce biofilms in vitro in the presence of bile. In this study, we further investigated the effects of bile on S. aureus biofilm formation. Most clinical S. aureus strains and the laboratory strain RN4220 were stimulated to form biofilms with sub-inhibitory concentrations of bovine bile. Additionally, we observed bile-induced sensitivity to aminoglycosides, which we exploited in a bursa aurealis transposon screen to isolate mutants reduced in aminoglycoside sensitivity and augmented in bile-induced biofilm formation. We identified five mutants that exhibited hypersensitivity to bile with respect to bile-induced biofilm formation, three of which carried transposon insertions within gene clusters involved in wall teichoic acid (WTA) biosynthesis or transport. Strain TM4 carried an insertion between the divergently oriented tagH and tagG genes, which encode the putative WTA membrane translocation apparatus. Ectopic expression of tagG in TM4 restored a wild-type bile-induced biofilm response, suggesting that reduced translocation of WTA in TM4 induced sensitivity to bile and enhanced the bile-induced biofilm formation response. We propose that WTA may be important for protecting S. aureus against exposure to bile and that bile-induced biofilm formation may be an evolved response to protect cells from bile-induced cell lysis.}, } @article {pmid27259704, year = {2016}, author = {Federman, C and Ma, C and Biswas, D}, title = {Major components of orange oil inhibit Staphylococcus aureus growth and biofilm formation, and alter its virulence factors.}, journal = {Journal of medical microbiology}, volume = {65}, number = {7}, pages = {688-695}, doi = {10.1099/jmm.0.000286}, pmid = {27259704}, issn = {1473-5644}, mesh = {Acyclic Monoterpenes ; Aldehydes/isolation & purification/pharmacology/toxicity ; Animals ; Anti-Bacterial Agents/*isolation & purification/*pharmacology/toxicity ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects/growth & development ; Cattle ; Cell Line ; Cell Survival/drug effects ; Endocytosis/drug effects ; Epithelial Cells/drug effects/physiology ; Gene Expression Profiling ; Microbial Sensitivity Tests ; Monoterpenes/isolation & purification/pharmacology/toxicity ; Plant Oils/*chemistry ; Real-Time Polymerase Chain Reaction ; Sesquiterpenes/isolation & purification/pharmacology/toxicity ; Staphylococcus aureus/*drug effects/physiology ; Virulence/drug effects ; Virulence Factors/analysis/genetics ; }, abstract = {Bovine mastitis is a costly disease in the dairy industry and does not always respond to antibiotic treatment. The major components of terpeneless, cold-pressed Valencia orange oil - citral, linalool, decanal and valencene - were examined as potential alternative treatments for Staphylococcus aureus-associated mastitis. The minimum inhibitory concentration (MIC) of all four components against S. aureus was determined after incubation for 24 h. Growth inhibition assays were performed for all effective components on S. aureus for either a 3 h or 72 h treatment. These components were tested for the ability to disrupt pre-formed S. aureus biofilms after 24 h of treatment by measuring absorbance at 540 nm. Cytotoxicity against immortalized bovine mammary epithelial (MAC-T) cells was measured using an MTT assay following a 1 h exposure. Only concentrations below the 50 % cytostatic concentration (CC50) were used in an adherence and invasion assay of S. aureus on MAC-T cells, and for measurements of virulence and biofilm gene expression via qPCR. The MICs of citral and linalool were 0.02 % and 0.12 %, respectively, but decanal and valencene were ineffective. Citral and linalool were capable of inhibiting growth of S. aureus after 24 h at their MIC values and inhibited pre-formed biofilms of S. aureus . The concentrations below the CC50 were 0.02 % for citral and 0.12 % for linalool. These concentrations inhibited the adhesion and invasion ability of S. aureus and downregulated virulence genes. Only 0.12 % linalool downregulated the expression of S. aureus biofilm-forming genes. These components should be considered for further in vivo study.}, } @article {pmid27259377, year = {2016}, author = {Rodrigues, CF and Silva, S and Azeredo, J and Henriques, M}, title = {Candida glabrata's recurrent infections: biofilm formation during Amphotericin B treatment.}, journal = {Letters in applied microbiology}, volume = {63}, number = {2}, pages = {77-81}, doi = {10.1111/lam.12600}, pmid = {27259377}, issn = {1472-765X}, mesh = {Amphotericin B/*therapeutic use ; Antifungal Agents/*therapeutic use ; Biofilms/drug effects/*growth & development ; Candida glabrata/*growth & development/isolation & purification/physiology ; Candidiasis/*drug therapy/microbiology/pathology ; Humans ; Polyenes ; Recurrence ; }, abstract = {UNLABELLED: Candida species are responsible for recurrent human infections, mostly in immunocompromised patients, due to their high vulnerability. Candida glabrata has a major role in systemic candidiasis and Amphotericin B (AmB), a polyene only used in hospitals, is frequently used to treat this disease. Lately, however, clinical evidences of Candida recurrent infections during these treatments are being described, probably due to biofilm (re)formation during this therapy. Thus, this work aims at inferring if C. glabrata biofilms are still being formed during AmB treatment. For that, C. glabrata biofilms were formed in the presence of AmB and analysed by dry weight. Matrix composition was analysed quantifying carbohydrates and, specifically, β-1,3 glucans. Results demonstrated that, although in a lesser extent, C. glabrata is able to develop biofilms in the presence of AmB, with a thick extracellular matrix, with an increase on carbohydrates, especially β-1,3 glucans. Therefore, it is confirmed that complex biofilms of C. glabrata can be formed during an AmB treatment.

This study shows new insights regarding recurrent candidiasis. The authors demonstrated that Amphotericin B did not totally prevent the development of biofilms during Candida glabrata's infection treatment and that the change in the biofilm matrices may have a high responsibility for the fail in the treatment of systemic candidiasis.}, } @article {pmid27259185, year = {2016}, author = {Di, W and Xing, M and Yang, J}, title = {Investigation on the difference between biofilm morphologies of the vermifilter and conventional biofilter with the flow cytometer.}, journal = {Bioresource technology}, volume = {216}, number = {}, pages = {308-316}, doi = {10.1016/j.biortech.2016.05.033}, pmid = {27259185}, issn = {1873-2976}, mesh = {Animals ; *Biofilms ; Filtration/*methods ; Flow Cytometry ; Oligochaeta ; *Sewage/chemistry/microbiology ; }, abstract = {With the demand of new sludge reduction processes, a vermifilter (VF) was studied based on a conventional biofilter (BF). The biofilm morphology was investigated using a new technique, the flow cytometer (FCM), to find a way to optimize VF structure. VF was inoculated with Eisenia fetida, packed with ceramsites, and operated stably at the organic load of 1.2kg-VSSm(-3)d(-1) with BF as the control. Compared with BF, VF had about 13% more removal efficiency of excess sludge and 45% shorter biofilm update period. FCM profile showed the morphology of microbial cells in VF biofilms was significantly different from that in BF in upper layers, with decreases of average refractive index (about 72%) and size (about 22%), and suggested it was better to keep earthworms there to remove rod-shaped microorganisms with other filter media in lower layers to remove spherical ones combining the findings in SEM images and extracellular polymeric substances.}, } @article {pmid27257751, year = {2016}, author = {Koo, H and Yamada, KM}, title = {Dynamic cell-matrix interactions modulate microbial biofilm and tissue 3D microenvironments.}, journal = {Current opinion in cell biology}, volume = {42}, number = {}, pages = {102-112}, pmid = {27257751}, issn = {1879-0410}, support = {R01 DE016139/DE/NIDCR NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025220/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Bacteria/*metabolism ; *Biofilms ; *Cell Communication ; Cell-Matrix Junctions/*metabolism ; *Cellular Microenvironment ; Extracellular Matrix/*metabolism ; Humans ; }, abstract = {Microbial biofilms and most eukaryotic tissues consist of cells embedded in a three-dimensional extracellular matrix. This matrix serves as a scaffold for cell adhesion and a dynamic milieu that provides varying chemical and physical signals to the cells. Besides a vast array of specific molecular components, an extracellular matrix can provide locally heterogeneous microenvironments differing in porosity/diffusion, stiffness, pH, oxygen and metabolites or nutrient levels. Mechanisms of matrix formation, mechanosensing, matrix remodeling, and modulation of cell-cell or cell-matrix interactions and dispersal are being revealed. This perspective article aims to identify such concepts from the fields of biofilm or eukaryotic matrix biology relevant to the other field to help stimulate new questions, approaches, and insights.}, } @article {pmid27256704, year = {2016}, author = {Marioni, J and Arce, JE and Cabrera, JL and Paraje, MG and Núñez Montoya, SC}, title = {Reduction of Candida tropicalis biofilm by photoactivation of a Heterophyllaea pustulata extract.}, journal = {Pharmaceutical biology}, volume = {54}, number = {12}, pages = {2791-2801}, doi = {10.1080/13880209.2016.1183683}, pmid = {27256704}, issn = {1744-5116}, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida tropicalis/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Humans ; Photic Stimulation/methods ; Photosensitizing Agents/isolation & purification/*pharmacology ; Plant Extracts/isolation & purification/*pharmacology ; Reactive Oxygen Species/antagonists & inhibitors/metabolism ; *Rubiaceae ; }, abstract = {CONTEXT: Biofilm formation is an important problem, since this growth mode confers resistance to drugs usually used in therapeutics.

OBJECTIVE: In vitro antifungal activity of extracts obtained from Heterophyllaea pustulata Hook f. (Rubiaceae) were studied against Candida tropicalis biofilms, evaluating the effect of irradiation and the oxidative and nitrosative stresses as possible mechanisms of action.

MATERIALS AND METHODS: Hexane, benzene, ethyl acetate and ethanol extracts were evaluated at three concentrations (0.2, 0.1 and 0.05 mg/mL) over mature biofilm, under darkness and irradiation. After 48 h of incubation, biofilm quantitation was performed by the O'Toole and Kolter method. Reactive oxygen species (ROS) was measured by nitro-blue tetrazolium (NBT) reaction and reactive nitrogen intermediates (RNI) by the Griess reagent. Superoxide dismutase activation (SOD, NBT assay) and total antioxidant system (FRAP test) were studied.

RESULTS: Only the benzene extract at 0.2 mg/mL reduced the biofilms formation. The slight decrease achieved in darkness (17.06 ± 2.80% reduction) was increased by light action (39.31 ± 3.50% reduction), clearly observing a photostimulation. This great reduction was confirmed by confocal microscopy. In darkness, biofilm reduction was mediated by an increase in RNI, whereas under irradiation, the ROS action was most important. Although no SOD activation was observed, a strong stimulation of the total antioxidant system was detected. HPLC analysis established a high content of several anthraquinones in this extract.

DISCUSSION AND CONCLUSION: Biofilm reduction by benzene extract was mainly mediated by oxidative stress triggered under light action, confirming a photodynamic sensitization, which could be attributed to its high content of photosensitizing anthraquinones.}, } @article {pmid27256532, year = {2016}, author = {Yue, JX and Yang, HY and Han, L and Zhu, MY and Song, FF and Huang, C}, title = {[Inhibitory effect of quercetin on the biofilm formation of Streptococcus mutans].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {51}, number = {6}, pages = {368-373}, doi = {10.3760/cma.j.issn.1002-0098.2016.06.010}, pmid = {27256532}, issn = {1002-0098}, mesh = {Antioxidants/*pharmacology ; Biofilms/*drug effects ; Dental Pulp/cytology ; Humans ; Microscopy, Confocal ; Quercetin/administration & dosage/*pharmacology ; Real-Time Polymerase Chain Reaction ; Staining and Labeling ; Streptococcus mutans/*physiology ; Tetrazolium Salts ; Time Factors ; }, abstract = {OBJECTIVE: To observe the inhibitory effect of quercetin on the biofilm formation of Streptococcus mutans(Sm), to preliminarily reveal the possible underlying mechanisms, and to evaluate the cytotoxicity of quercetion to human dental pulp cells so as to provide the theoretical basis for the application of quercetin in oral biomaterials.

METHODS: Quercetin storage solution was diluted to 0, 3.125, 6.25, 12.5, 25, 50, 100, 200, 400 and 800 mg/L, and added into Sm medium for 4 h and 24 h, crystal violet staining was used to evaluate the biofilm volume. In subsequent detections, three groups were set: control(0 mg/L), 200 mg/L quercetin and 400 mg/L quercetin. Confocal laser scanning microscopy was used to observe the morphology of the biofilm; qPCR for gtfB, gtfC, comD, comE, and luxS were assessed to preliminarily investigate the mechanisms. Finally, the methyl thiazolyl tetrazolium(MTT)test using human dental pulp cells was used to investigate cytotoxicity.

RESULTS: Quercetin could significantly inhibit up to(86.16±0.45)% of the biofilm formation of Sm(Compared with the control group P=0.00)and effectively removed(43.04±0.53)% of the mature biofilm(Compared with the control group P=0.00). Confocal laser scanning microscopy photographs showed that after co-incubated for 24 h, the dense biofilm structures of the experimental group were destroyed by quercetin both at 200 mg/L and 400 mg/L. Quercetin suppressedover 50% of the expression of gtfB, gtfC, comD, comE(compared with the control group P<0.05)and promoted the expression of luxS up to 2.18 ± 0.24 and 2.84 ± 0.26 after 4 h and 24 h, respectively(compared with the control group P<0.05). Quercetin also exhibited acceptable compatibility for human dental pulp cells.

CONCLUSIONS: Quercetin could effectively reduce the biofilm formation of Sm by inhibiting the expression of the related genes, and exhibited no cytotoxicity for human dental pulp cells. Quercetin has good potential to be applied in oral biological materials.}, } @article {pmid27255983, year = {2016}, author = {Feng, Z and Zhu, P and Fan, H and Piao, S and Xu, L and Sun, T}, title = {Effect of Biofilm on Passive Sampling of Dissolved Orthophosphate Using the Diffusive Gradients in Thin Films Technique.}, journal = {Analytical chemistry}, volume = {88}, number = {13}, pages = {6836-6843}, doi = {10.1021/acs.analchem.6b01392}, pmid = {27255983}, issn = {1520-6882}, abstract = {We evaluated the possibility of sampling dissolved orthophosphate using the diffusive gradient in thin films (DGT) technique with a phosphate ion-imprinted polymer (PIP)-based adsorbent and assessed the effect of biofilm on the DGT measurement. The composition of biofilm formed on the DGT surface was analyzed, and the effect of biofouling on the diffusion coefficient of the analyte was investigated. The corrected diffusion coefficient for the biofouled DGT was estimated and used for the calculation of the DGT equation. PIP-binding gels had a higher adsorption affinity for orthophosphate than for the other anions, indicating its selectivity for orthophosphate. The concentrations predicted via DGT agreed well with the concentrations determined in the bulk solutions. Sampling of orthophosphate using PIP-DGT was consistent over a pH range of 3-9 and ionic strength range of 0.01-10 000 μM. Other P compounds cannot be measured using the PIP-DGT technique. The diffusion coefficient of the orthophosphate linearly decreased with increasing thickness of the biofilm. This sampling method performed predictably in freshwater when the biofilm was not formed or when value for the biofilm interference was reduced by using the corrected diffusion coefficient.}, } @article {pmid27255108, year = {2016}, author = {Salimena, AP and Lange, CC and Camussone, C and Signorini, M and Calvinho, LF and Brito, MA and Borges, CA and Guimarães, AS and Ribeiro, JB and Mendonça, LC and Piccoli, RH}, title = {Genotypic and phenotypic detection of capsular polysaccharide and biofilm formation in Staphylococcus aureus isolated from bovine milk collected from Brazilian dairy farms.}, journal = {Veterinary research communications}, volume = {40}, number = {3-4}, pages = {97-106}, pmid = {27255108}, issn = {1573-7446}, mesh = {Animals ; *Biofilms ; Brazil ; Cattle ; Enzyme-Linked Immunosorbent Assay ; Genes, Bacterial/genetics ; Genotype ; Mastitis, Bovine/microbiology ; Milk/*microbiology ; Phenotype ; Polysaccharides, Bacterial/*genetics ; Staphylococcus aureus/genetics/isolation & purification/*physiology ; }, abstract = {Staphylococcus aureus is a pathogen that frequently causes mastitis in bovine herds worldwide. This pathogen produces several virulence factors, including cell-associated adhesins, toxic and cytolytic exoproteins, and capsular polysaccharides. The aim of the present study was to test for the presence of genes involved in capsular polysaccharide production and biofilm formation in S. aureus isolated from bovine mastitis samples collected from 119 dairy herds located in three different Brazilian regions, as well as to assay the production of capsular polysaccharides and biofilm, in vitro. The detection of the cap, icaAD, and bap genes was performed using PCR. The detection and quantification of capsular polysaccharide production was performed using ELISA assays. The ability of the isolates to form a biofilm was examined using the polystyrene surface of microtiter plates. All 159 S. aureus isolates investigated harboured the cap gene: 80 % carried the cap5 gene and 20 % carried the cap8 gene. Sixty-nine percent of the isolates expressed capsular polysaccharide (CP) in vitro, 58 % expressed CP5 and 11 % expressed CP8. All of the isolates harboured the icaA and icaD genes, and 95.6 % of the isolates carried the bap gene. Of the 159 isolates analysed, 97.5 % were biofilm producers. A significant association between the capsular genotype and phenotype and the amount of biofilm formation was detected: cap5/CP5 isolates tended to form more biofilm and to produce a thinner CP layer than cap8/CP8 isolates. The results indicate a high potential for pathogenicity among S. aureus isolated from bovine milk collected from three different regions in Brazil.}, } @article {pmid27254294, year = {2016}, author = {Jayashree, C and Tamilarasan, K and Rajkumar, M and Arulazhagan, P and Yogalakshmi, KN and Srikanth, M and Banu, JR}, title = {Treatment of seafood processing wastewater using upflow microbial fuel cell for power generation and identification of bacterial community in anodic biofilm.}, journal = {Journal of environmental management}, volume = {180}, number = {}, pages = {351-358}, doi = {10.1016/j.jenvman.2016.05.050}, pmid = {27254294}, issn = {1095-8630}, mesh = {Bioelectric Energy Sources/*microbiology ; *Biofilms ; Biological Oxygen Demand Analysis ; Electricity ; Electrodes ; Seafood ; Stenotrophomonas/classification/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/analysis/*microbiology ; Water Purification/*methods ; }, abstract = {Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d(-1), the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m(-2) (2.21 W m(-3)) was achieved at an OLR of 2.57 g d(-1). The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment.}, } @article {pmid27253749, year = {2016}, author = {Fernández-Delgado, M and Rojas, H and Duque, Z and Suárez, P and Contreras, M and García-Amado, MA and Alciaturi, C}, title = {BIOFILM FORMATION OF Vibrio cholerae ON STAINLESS STEEL USED IN FOOD PROCESSING.}, journal = {Revista do Instituto de Medicina Tropical de Sao Paulo}, volume = {58}, number = {}, pages = {47}, pmid = {27253749}, issn = {1678-9946}, mesh = {Biofilms/*growth & development ; *Food Handling ; Humans ; Microscopy, Electron, Scanning ; *Stainless Steel ; Vibrio cholerae/drug effects/*growth & development ; }, abstract = {Vibrio cholerae represents a significant threat to human health in developing countries. This pathogen forms biofilms which favors its attachment to surfaces and its survival and transmission by water or food. This work evaluated the in vitro biofilm formation of V. cholerae isolated from clinical and environmental sources on stainless steel of the type used in food processing by using the environmental scanning electron microscopy (ESEM). Results showed no cell adhesion at 4 h and scarce surface colonization at 24 h. Biofilms from the environmental strain were observed at 48 h with high cellular aggregations embedded in Vibrio exopolysaccharide (VPS), while less confluence and VPS production with microcolonies of elongated cells were observed in biofilms produced by the clinical strain. At 96 h the biofilms of the environmental strain were released from the surface leaving coccoid cells and residual structures, whereas biofilms of the clinical strain formed highly organized structures such as channels, mushroom-like and pillars. This is the first study that has shown the in vitro ability of V. cholerae to colonize and form biofilms on stainless steel used in food processing.}, } @article {pmid27253324, year = {2016}, author = {Jang, CH and Piao, YL and Huang, X and Yoon, EJ and Park, SH and Lee, K and Zhan, CG and Cho, H}, title = {Modeling and Re-Engineering of Azotobacter vinelandii Alginate Lyase to Enhance Its Catalytic Efficiency for Accelerating Biofilm Degradation.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0156197}, pmid = {27253324}, issn = {1932-6203}, mesh = {Alginates/chemistry/metabolism ; Amino Acid Sequence/genetics ; Anti-Bacterial Agents/chemistry/pharmacology ; Azotobacter vinelandii/enzymology ; Biofilms/drug effects ; *Catalysis ; Glucuronic Acid/chemistry/metabolism ; Hexuronic Acids/chemistry/metabolism ; Mutagenesis, Site-Directed ; Mutant Proteins/*chemistry/genetics/pharmacology ; Penicillanic Acid/analogs & derivatives/pharmacology ; Piperacillin/pharmacology ; Polysaccharide-Lyases/*chemistry/genetics/pharmacology ; Pseudomonas aeruginosa/*drug effects ; Tazobactam ; }, abstract = {Alginate is known to prevent elimination of Pseudomonas aeruginosa biofilms. Alginate lyase (AlgL) might therefore facilitate treatment of Pseudomonas aeruginosa-infected cystic fibrosis patients. However, the catalytic activity of wild-type AlgL is not sufficiently high. Therefore, molecular modeling and site-directed mutagenesis of AlgL might assist in enzyme engineering for therapeutic development. AlgL, isolated from Azotobacter vinelandii, catalyzes depolymerization of alginate via a β-elimination reaction. AlgL was modeled based on the crystal structure template of Sphingomonas AlgL species A1-III. Based on this computational analysis, AlgL was subjected to site-directed mutagenesis to improve its catalytic activity. The kcat/Km of the K194E mutant showed a nearly 5-fold increase against the acetylated alginate substrate, as compared to the wild-type. Double and triple mutants (K194E/K245D, K245D/K319A, K194E/K245D/E312D, and K194E/K245D/K319A) were also prepared. The most potent mutant was observed to be K194E/K245D/K319A, which has a 10-fold improved kcat value (against acetylated alginate) compared to the wild-type enzyme. The antibiofilm effect of both AlgL forms was identified in combination with piperacillin/tazobactam (PT) and the disruption effect was significantly higher in mutant AlgL combined with PT than wild-type AlgL. However, for both the wild-type and K194E/K245D/K319A mutant, the use of the AlgL enzyme alone did not show significant antibiofilm effect.}, } @article {pmid27253076, year = {2016}, author = {Kao, WT and Gagnon, PM and Vogel, JP and Chole, RA}, title = {FleQ, a Transcriptional Activator, Is Required for Biofilm Formation In Vitro But Does Not Alter Virulence in a Cholesteatomas Model.}, journal = {Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology}, volume = {37}, number = {7}, pages = {977-983}, pmid = {27253076}, issn = {1537-4505}, support = {R01 DC000263/DC/NIDCD NIH HHS/United States ; P30 DC004665/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Cholesteatoma, Middle Ear/*microbiology ; Disease Models, Animal ; Gerbillinae ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/*pathogenicity ; Trans-Activators/*metabolism ; Virulence/*physiology ; Virulence Factors/metabolism ; }, abstract = {HYPOTHESIS: Bacterial biofilm formation within cholesteatomas is responsible for increased persistence and tissue destruction and Pseudomonas aeruginosa deficient in biofilm formation (PAO1 ΔfleQ) are less virulent than the parent bacteria.

BACKGROUND: Infected aural cholesteatomas have been demonstrated to be more destructive than uninfected cholesteatomas and infections are more persistent. The chronicity and persistence of infections within cholesteatomas may be because of the presence of biofilm formation.

METHODS: Twenty-seven mutant strains of PAO1 were screened for surface adherence. These strains were also screened for static biofilm formation. The biofilms were quantified by staining with crystal violet. Aural cholesteatomas were then induced in Mongolian gerbils by ligation of the ear canal. At the time of ligation, the ear canals were inoculated with wild-type PAO1 and a biofilm deficient PAO1 ΔfleQ strain of P. aeruginosa. A 7 weeks course of ciprofloxacin (20 mg/kg/day) was started on postoperative day 7. Eight weeks after induction of cholesteatomas, the cholesteatoma size, levels of bone destruction, and levels of bone remodeling were evaluated using microCT imaging.

RESULTS: PAO1 ΔfleQ was identified as a poorly adherent and deficient biofilm forming mutant strain of P. aeruginosa. Infected cholesteatomas had more growth, bone destruction and bone remodeling than uninfected cholesteatomas. However, there was no difference observed between cholesteatomas infected with PAO1 (biofilm competent strain) and PAO1 ΔfleQ (biofilm deficient strain).

CONCLUSION: We demonstrate that the biofilm phenotype is not an important virulence factor in cholesteatomas infected with P. aeruginosa.}, } @article {pmid27252939, year = {2016}, author = {Vijayakumar, S and Rajenderan, S and Laishram, S and Anandan, S and Balaji, V and Biswas, I}, title = {Biofilm Formation and Motility Depend on the Nature of the Acinetobacter baumannii Clinical Isolates.}, journal = {Frontiers in public health}, volume = {4}, number = {}, pages = {105}, pmid = {27252939}, issn = {2296-2565}, abstract = {Acinetobacter baumannii is a nosocomial pathogen involved in various infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteremia. The severity and the type of infections depend on the genetic and phenotypic variations of the strains. In this study, we compared the extent of biofilm formation and motility displayed by 60 multidrug-resistant A. baumannii clinical strains isolated from blood and sputum samples from patients from Southern India. Our results showed that isolates from the sputum samples formed significantly more robust biofilm compared to the blood isolates. On the other hand, we observed that the blood isolates were more motile than the sputum isolates. To the best of our knowledge, this is the first study that systematically evaluated the correlation between these two phenotypic traits and the nature of the isolates.}, } @article {pmid27252918, year = {2016}, author = {Yousefi, M and Pourmand, MR and Fallah, F and Hashemi, A and Mashhadi, R and Nazari-Alam, A}, title = {Characterization of Staphylococcus aureus Biofilm Formation in Urinary Tract Infection.}, journal = {Iranian journal of public health}, volume = {45}, number = {4}, pages = {485-493}, pmid = {27252918}, issn = {2251-6085}, abstract = {BACKGROUND: The aim of this study was to investigate the antibiotic susceptibility pattern as well as the phenotypic and genotypic biofilm formation ability of Staphylococcus aureus isolates from patients with urinary tract infection (UTI).

METHODS: A total of 39 isolates of S. aureus were collected from patients with UTI. The antibiotic susceptibility patterns of the isolates were determined by the Kirby-Bauer disk-diffusion. We used the Modified Congo red agar (MCRA) and Microtiter plate methods to assess the ability of biofilm formation. All isolates were examined for determination of biofilm related genes, icaA, fnbA, clfA and bap using PCR method.

RESULTS: Linezolid, quinupristin/dalfopristin and chloramphenicol were the most effective agents against S. aureus isolates. Overall, 69.2% of S. aureus isolates were biofilm producers. Resistance to four antibiotics such as nitrofurantoin (71.4% vs. 28.6%, P=0.001), tetracycline (57.7% vs. 42.3%, P=0.028), erythromycin and ciprofloxacin (56% vs. 44%, P=0.017) was higher among biofilm producers than non-biofilm producers. The icaA, fnbA and clfA genes were present in all S. aureus isolates. However, bap gene was not detected in any of the isolates.

CONCLUSION: Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Trimethoprimsulfamethoxazole and doxycycline may be used as an effective treatment for UTI caused by biofilm producers S. aureus. Our results suggest that biofilm formation is not dependent to just icaA, fnbA, clfA and bap genes harbor in S. aureus strains.}, } @article {pmid27252699, year = {2016}, author = {Gundlach, J and Rath, H and Herzberg, C and Mäder, U and Stülke, J}, title = {Second Messenger Signaling in Bacillus subtilis: Accumulation of Cyclic di-AMP Inhibits Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {804}, pmid = {27252699}, issn = {1664-302X}, abstract = {The Gram-positive model organism Bacillus subtilis produces the essential second messenger signaling nucleotide cyclic di-AMP. In B. subtilis and other bacteria, c-di-AMP has been implicated in diverse functions such as control of metabolism, cell division and cell wall synthesis, and potassium transport. To enhance our understanding of the multiple functions of this second messenger, we have studied the consequences of c-di-AMP accumulation at a global level by a transcriptome analysis. C-di-AMP accumulation affected the expression of about 700 genes, among them the two major operons required for biofilm formation. The expression of both operons was severely reduced both in the laboratory and a non-domesticated strain upon accumulation of c-di-AMP. In excellent agreement, the corresponding strain was unable to form complex colonies. In B. subtilis, the transcription factor SinR controls the expression of biofilm genes by binding to their promoter regions resulting in transcription repression. Inactivation of the sinR gene restored biofilm formation even at high intracellular c-di-AMP concentrations suggesting that the second messenger acts upstream of SinR in the signal transduction pathway. As c-di-AMP accumulation did not affect the intracellular levels of SinR, we conclude that the nucleotide affects the activity of SinR.}, } @article {pmid27251096, year = {2016}, author = {Khoramrooz, SS and Mansouri, F and Marashifard, M and Malek Hosseini, SA and Akbarian Chenarestane-Olia, F and Ganavehei, B and Gharibpour, F and Shahbazi, A and Mirzaii, M and Darban-Sarokhalil, D}, title = {Detection of biofilm related genes, classical enterotoxin genes and agr typing among Staphylococcus aureus isolated from bovine with subclinical mastitis in southwest of Iran.}, journal = {Microbial pathogenesis}, volume = {97}, number = {}, pages = {45-51}, doi = {10.1016/j.micpath.2016.05.022}, pmid = {27251096}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/genetics ; Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cattle ; Enterotoxins/*genetics ; Genotype ; Iran/epidemiology ; Mastitis, Bovine/epidemiology/*microbiology ; Molecular Epidemiology ; *Molecular Typing ; Multiplex Polymerase Chain Reaction ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus aureus/*genetics/isolation & purification/physiology ; Trans-Activators/*genetics ; }, abstract = {Staphylococcus aureus by producing biofilm and facilitating chronic infection is a common cause of mastitis in cows and thereby can cause food poisoning by production of enterotoxins in milk. The agr typing method is an important tool for epidemiological investigation about S. aureus. The aims of the present study were to detect biofilm related genes, 5 classical enterotoxin genes and the agr types among S. aureus isolates. The ability of S. aureus isolates to produce biofilm was evaluated by modified CRA plate. Six biofilm related adhesion genes (icaD, icaA, fnbA, bap, clfA and cna), five classical enterotoxin genes (sea, seb, sec, sed and see) and tst-1 gene were detected by PCR methods. Multiplex-PCR was used to determination of the agr groups. 55 out of 80(68.8%) S. aureus isolates were biofilm producer. The icaD gene was detected in 70 (87.5%) of isolates. The prevalence rates of fnbA, icaA, clfA, cna and bap were 72.5, 56.25, 50, 22.5, and 5% respectively. The agr group I and III were detected in 57.5% 25% of studied isolates. The sea, sed and tst-1 genes were found in 10%, 7.5% and 1.25% of isolates respectively. The majority of S. aureus were able to produce biofilm. Significant associations were observed between presence of the icaD, icaA, fnbA, clfA and the cna genes as well as biofilm formation. The present study revealed that isolates with the agr type III are more potent for biofilm production. Our data supported a possible link between the agr types and certain SE genes.}, } @article {pmid27250993, year = {2017}, author = {Vavlekas, DA}, title = {Construction and evaluation of a modular biofilm-forming chamber for microbial recovery of neodymium and semi-continuous biofilm preparation. Tolerance of Serratia sp.N14 on acidic conditions and neutralized aqua regia.}, journal = {Environmental technology}, volume = {38}, number = {3}, pages = {239-256}, doi = {10.1080/09593330.2016.1189971}, pmid = {27250993}, issn = {1479-487X}, mesh = {Biofilms ; *Bioreactors ; Hydrochloric Acid ; Hydrogen-Ion Concentration ; Neodymium/*metabolism ; Nitric Acid ; Phosphates/*metabolism ; Serratia/growth & development/*metabolism ; }, abstract = {Recovery of neodymium from liquid metallic wastes and scrap leachates is a crucial step for its recycling, which can take place through the immobilized biofilms of Serratia sp. N14. These biofilms are produced in a fermentor vessel with a turnaround time of 10-14 days, which is unacceptable from an economic point of view for an industrial process. This study proposes the construction and evaluation of a modular system, whereby a biofilm-forming chamber is inserted into the continuous biomass outflow of the main chemostat vessel, for an alternative semi-continuous and economic production of biofilm. The activity of the biofilm from the outflow chamber was found to be the same as the one from the main chamber, which was stored in a cold room (4°C), for 9-12 months, depending on a 24 h nucleation step.Moreover, the ability of the biofilm to function in the presence of a leaching agent (aqua regia) or in acidic conditions was also evaluated. The biofilm of the main chamber can remain active even at 50% neutralized aqua regia (pH 3.0), while at acidic conditions, phosphate release of the cells is reduced to 50%. This strain proves to be very tolerant in low pH or high salt concentration solutions. The biofilm produced from the outflow of the main fermentor vessel is of acceptable activity, rather than being disposed.}, } @article {pmid27248687, year = {2016}, author = {Sena-Vélez, M and Redondo, C and Graham, JH and Cubero, J}, title = {Presence of Extracellular DNA during Biofilm Formation by Xanthomonas citri subsp. citri Strains with Different Host Range.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0156695}, pmid = {27248687}, issn = {1932-6203}, mesh = {*Biofilms ; DNA/*analysis ; Microscopy, Fluorescence ; Xanthomonas/genetics/*metabolism ; }, abstract = {Xanthomonas citri subsp. citri (Xcc) A strain causes citrus bacterial canker, a serious leaf, fruit and stem spotting disease of several Citrus species. X. alfalfae subsp. citrumelonis (Xac) is the cause of citrus bacterial spot, a minor disease of citrus nursery plants and X. campestris pv. campestris (Xc) is a systemic pathogen that causes black rot of cabbage. Xanthomonas spp. form biofilms in planta that facilitate the host infection process. Herein, the role of extracellular DNA (eDNA) was evaluated in the formation and stabilization of the biofilm matrix at different stages of biofilm development. Fluorescence and light microscopy, as well as DNAse treatments, were used to determine the presence of eDNA in biofilms and bacterial cultures. DNAse treatments of Xcc strains and Xac reduced biofilm formation at the initial stage of development, as well as disrupted preformed biofilm. By comparison, no significant effect of the DNAse was detected for biofilm formation by Xc. DNAse effects on biofilm formation or disruption varied among Xcc strains and Xanthomonas species which suggest different roles for eDNA. Variation in the structure of fibers containing eDNA in biofilms, bacterial cultures, and in twitching motility was also visualized by microscopy. The proposed roles for eDNA are as an adhesin in the early stages of biofilm formation, as an structural component of mature bacterial aggregates, and twitching motility structures.}, } @article {pmid27247623, year = {2016}, author = {Rajendran, A and Hu, B}, title = {Mycoalgae biofilm: development of a novel platform technology using algae and fungal cultures.}, journal = {Biotechnology for biofuels}, volume = {9}, number = {}, pages = {112}, pmid = {27247623}, issn = {1754-6834}, abstract = {BACKGROUND: Microalgae is considered a promising source for biofuel and bioenergy production, bio-remediation and production of high-value bioactive compounds, but harvesting microalgae is a major bottleneck in the algae based processes. The objective of this research is to mimic the growth of natural lichen and develop a novel biofilm platform technology using filamentous fungi and microalgae to form a lichen type of biofilm "mycoalgae" in a supporting polymer matrix.

RESULTS: The possibility of co-existence of Chlorella vulgaris with various fungal cultures was tested to identify the best strain combination for high algae harvest efficiency. The effect of different matrices for cell attachment and biofilm formation, cell surface characterization of mycoalgae biofilm, kinetics of the process with respect to the algae-fungi cell distribution and total biomass production was studied. Mycoalgae biofilm with algae attachment efficiency of 99.0 % and above was achieved in a polymer-cotton composite matrix with glucose concentration of 2 g/L in the growth medium and agitation intensity of 150 rpm at 27 °C. The total biomass in the co-culture with the selected strain combination (Mucor sp. and Chlorella sp.) was higher than the axenic cultures of fungi and algae at the conditions tested.

CONCLUSIONS: The results show that algae can be grown with complete attachment to a bio-augmenting fungal surface and can be harvested readily as a biofilm for product extraction from biomass. Even though, interaction between heterotrophic fungi and phototrophic algae was investigated in solid media after prolonged contact in a report, this research is the first of its kind in developing an artificial lichen type biofilm called "mycoalgae" biofilm completely attached on a matrix in liquid cultures. The mycoalgae biofilm based processes, propounds the scope for exploring new avenues in the bio-production industry and bioremediation.}, } @article {pmid27245927, year = {2016}, author = {Basak, A and Abouelhassan, Y and Norwood, VM and Bai, F and Nguyen, MT and Jin, S and Huigens, RW}, title = {Synthetically Tuning the 2-Position of Halogenated Quinolines: Optimizing Antibacterial and Biofilm Eradication Activities via Alkylation and Reductive Amination Pathways.}, journal = {Chemistry (Weinheim an der Bergstrasse, Germany)}, volume = {22}, number = {27}, pages = {9181-9189}, doi = {10.1002/chem.201600926}, pmid = {27245927}, issn = {1521-3765}, mesh = {Alkylation ; Amination ; Anti-Bacterial Agents/*chemical synthesis/pharmacology/toxicity ; Biofilms/drug effects ; Cell Survival/drug effects ; Drug Resistance, Bacterial/drug effects ; Enterococcus faecium/drug effects/physiology ; Erythrocytes/cytology/drug effects/metabolism ; Halogenation ; HeLa Cells ; Hemolysis/drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/physiology ; Quinolines/*chemistry/pharmacology/toxicity ; Staphylococcus/drug effects ; Structure-Activity Relationship ; }, abstract = {Agents capable of eradicating bacterial biofilms are of great importance to human health as biofilm-associated infections are tolerant to our current antibiotic therapies. We have recently discovered that halogenated quinoline (HQ) small molecules are: 1) capable of eradicating methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE) and vancomycin-resistant Enterococcus faecium (VRE) biofilms, and 2) synthetic tuning of the 2-position of the HQ scaffold has a significant impact on antibacterial and antibiofilm activities. Here, we report the chemical synthesis and biological evaluation of 39 HQ analogues that have a high degree of structural diversity at the 2-position. We identified diverse analogues that are alkylated and aminated at the 2-position of the HQ scaffold and demonstrate potent antibacterial (MIC≤0.39 μm) and biofilm eradication (MBEC 1.0-93.8 μm) activities against drug-resistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium strains while demonstrating <5 % haemolysis activity against human red blood cells (RBCs) at 200 μm. In addition, these HQs demonstrated low cytotoxicity against HeLa cells. Halogenated quinolines are a promising class of antibiofilm agents against Gram-positive pathogens that could lead to useful treatments against persistent bacterial infections.}, } @article {pmid27242714, year = {2016}, author = {Crespo, A and Pedraz, L and Astola, J and Torrents, E}, title = {Pseudomonas aeruginosa Exhibits Deficient Biofilm Formation in the Absence of Class II and III Ribonucleotide Reductases Due to Hindered Anaerobic Growth.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {688}, pmid = {27242714}, issn = {1664-302X}, abstract = {Chronic lung infections by the ubiquitous and extremely adaptable opportunistic pathogen Pseudomonas aeruginosa correlate with the formation of a biofilm, where bacteria grow in association with an extracellular matrix and display a wide range of changes in gene expression and metabolism. This leads to increased resistance to physical stress and antibiotic therapies, while enhancing cell-to-cell communication. Oxygen diffusion through the complex biofilm structure generates an oxygen concentration gradient, leading to the appearance of anaerobic microenvironments. Ribonucleotide reductases (RNRs) are a family of highly sophisticated enzymes responsible for the synthesis of the deoxyribonucleotides, and they constitute the only de novo pathway for the formation of the building blocks needed for DNA synthesis and repair. P. aeruginosa is one of the few bacteria encoding all three known RNR classes (Ia, II, and III). Class Ia RNRs are oxygen dependent, class II are oxygen independent, and class III are oxygen sensitive. A tight control of RNR activity is essential for anaerobic growth and therefore for biofilm development. In this work we explored the role of the different RNR classes in biofilm formation under aerobic and anaerobic initial conditions and using static and continuous-flow biofilm models. We demonstrated the importance of class II and III RNR for proper cell division in biofilm development and maturation. We also determined that these classes are transcriptionally induced during biofilm formation and under anaerobic conditions. The molecular mechanism of their anaerobic regulation was also studied, finding that the Anr/Dnr system is responsible for class II RNR induction. These data can be integrated with previous knowledge about biofilms in a model where these structures are understood as a set of layers determined by oxygen concentration and contain cells with different RNR expression profiles, bringing us a step closer to the understanding of this complex growth pattern, essential for P. aeruginosa chronic infections.}, } @article {pmid27242678, year = {2016}, author = {Liu, C and Pan, F and Guo, J and Yan, W and Jin, Y and Liu, C and Qin, L and Fang, X}, title = {Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {621}, pmid = {27242678}, issn = {1664-302X}, abstract = {BACKGROUND: Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare.

METHODS: A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined.

RESULTS: The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like . The main type was blaOXA-114q . The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate.

CONCLUSION: Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes.}, } @article {pmid27242675, year = {2016}, author = {Diaz, M and Ladero, V and Del Rio, B and Redruello, B and Fernández, M and Martin, MC and Alvarez, MA}, title = {Biofilm-Forming Capacity in Biogenic Amine-Producing Bacteria Isolated from Dairy Products.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {591}, pmid = {27242675}, issn = {1664-302X}, abstract = {Biofilms on the surface of food industry equipment are reservoirs of potentially food-contaminating bacteria-both spoilage and pathogenic. However, the capacity of biogenic amine (BA)-producers to form biofilms has remained largely unexamined. BAs are low molecular weight, biologically active compounds that in food can reach concentrations high enough to be a toxicological hazard. Fermented foods, especially some types of cheese, accumulate the highest BA concentrations of all. The present work examines the biofilm-forming capacity of 56 BA-producing strains belonging to three genera and 10 species (12 Enterococcus faecalis, 6 Enterococcus faecium, 6 Enterococcus durans, 1 Enterococcus hirae, 12 Lactococcus lactis, 7 Lactobacillus vaginalis, 2 Lactobacillus curvatus, 2 Lactobacillus brevis, 1 Lactobacillus reuteri, and 7 Lactobacillus parabuchneri), all isolated from dairy products. Strains of all the tested species - except for L. vaginalis-were able to produce biofilms on polystyrene and adhered to stainless steel. However, the biomass produced in biofilms was strain-dependent. These results suggest that biofilms may provide a route via which fermented foods can become contaminated by BA-producing microorganisms.}, } @article {pmid27242375, year = {2016}, author = {Pompilio, A and Crocetta, V and Verginelli, F and Di Bonaventura, G}, title = {In vitro activity of levofloxacin against planktonic and biofilm Stenotrophomonas maltophilia lifestyles under conditions relevant to pulmonary infection in cystic fibrosis, and relationship with SmeDEF multidrug efflux pump expression.}, journal = {FEMS microbiology letters}, volume = {363}, number = {14}, pages = {}, doi = {10.1093/femsle/fnw145}, pmid = {27242375}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Cystic Fibrosis/complications ; Gene Expression Regulation, Bacterial/*drug effects ; *Genes, MDR ; Gram-Negative Bacterial Infections/etiology/microbiology ; Humans ; Levofloxacin/*pharmacology ; Pneumonia, Bacterial/etiology/microbiology ; Stenotrophomonas maltophilia/*drug effects/*physiology ; }, abstract = {The activity of levofloxacin against planktonic and biofilm Stenotrophomonas maltophilia cells and the role played by the multidrug efflux pump SmeDEF were evaluated under conditions relevant to the cystic fibrosis (CF) lung. MIC, MBC and MBEC of levofloxacin were assessed, against five CF strains, under 'standard' (CLSI-recommended) and 'CF-like' (pH 6.8, 5% CO2, in a synthetic CF sputum) conditions. Levofloxacin was tested against biofilms at concentrations (10, 50 and 100 μg mL(-1)) corresponding to achievable serum levels and sputum levels by aerosolisation. smeD expression was evaluated, under both conditions, in planktonic and biofilm cells by RT-PCR. The bactericidal effect of levofloxacin was decreased, in three out of five strains tested, under 'CF-like' conditions (MBC: 2-4 vs 8-16 μg mL(-1), under 'standard' and 'CF-like' conditions, respectively). Biofilm was intrinsically resistant to levofloxacin, regardless of conditions tested (MBECs ≥ 100 μg mL(-1) for all strains). Only under 'CF-like' conditions, smeD expression increased during planktonic-to-biofilm transition, and in biofilm cells compared to stationary planktonic cells. Our findings confirmed that S. maltophilia biofilm is intrinsically resistant to therapeutic concentrations of levofloxacin. Under conditions relevant to CF, smeD overexpression could contribute to levofloxacin resistance. Further studies are warranted to define the clinical relevance of our findings.}, } @article {pmid27242142, year = {2016}, author = {Chen, L and Bu, Q and Xu, H and Liu, Y and She, P and Tan, R and Wu, Y}, title = {The effect of berberine hydrochloride on Enterococcus faecalis biofilm formation and dispersion in vitro.}, journal = {Microbiological research}, volume = {186-187}, number = {}, pages = {44-51}, doi = {10.1016/j.micres.2016.03.003}, pmid = {27242142}, issn = {1618-0623}, mesh = {Aminoacyltransferases/antagonists & inhibitors/biosynthesis ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/biosynthesis ; Berberine/*pharmacology ; Biofilms/*drug effects ; Cysteine Endopeptidases/biosynthesis ; Enterococcus faecalis/*drug effects/isolation & purification/physiology ; Gene Expression/drug effects ; Humans ; Membrane Proteins/antagonists & inhibitors/biosynthesis ; Urinary Tract Infections/microbiology ; Urine/microbiology ; }, abstract = {Enterococcus faecalis (E. faecalis) is one of the major causes of biofilm infections. Berberine hydrochloride (BBH) has diverse pharmacological effects; however, the effects and mechanisms of BBH on E. faecalis biofilm formation and dispersion have not been reported. In this study, 99 clinical isolates from the urine samples of patients with urinary tract infections (UTIs) were collected and identified. Ten strains of E. faecalis with biofilm formation ability were studied. BBH inhibited E. faecalis biofilm formation and promoted the biofilm dispersion of E. faecalis. In addition, sortase A and esp expression levels were elevated during early E. faecalis biofilm development, whereas BBH significantly reduced their expression levels. The results of this study indicated that BBH effectively prevents biofilm formation and promotes biofilm dispersion in E. faecalis, most likely by inhibiting the expressions of sortase A and esp.}, } @article {pmid27241780, year = {2016}, author = {Tyner, H and Patel, R}, title = {Propionibacterium acnes biofilm - A sanctuary for Staphylococcus aureus?.}, journal = {Anaerobe}, volume = {40}, number = {}, pages = {63-67}, doi = {10.1016/j.anaerobe.2016.05.014}, pmid = {27241780}, issn = {1095-8274}, mesh = {Aerobiosis ; Anaerobiosis ; Biofilms/*drug effects/growth & development ; Coculture Techniques ; Microbial Viability/drug effects ; Oxygen/*pharmacology ; Plankton/*drug effects/growth & development ; Propionibacterium acnes/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {The purpose of this study was to measure the effect of combined culture of Propionibacterium acnes and Staphylococcus aureus on biofilm formation under different oxygen concentrations. We measured planktonic growth and biofilm formation of P. acnes and S. aureus alone and together under aerobic and anaerobic conditions. Both P. acnes and S. aureus grew under anaerobic conditions. When grown under anaerobic conditions, P. acnes with or without S. aureus formed a denser biomass biofilm than did S. aureus alone. Viable S. aureus was recovered from a16-day old combined P. acnes and S. aureus biofilm, but not a monomicrobial S. aureus biofilm.}, } @article {pmid27239550, year = {2016}, author = {Pedrazzi, V and Leite, MF and Tavares, RC and Sato, S and do Nascimento, GC and Issa, JP}, title = {Corrigendum to "Herbal Mouthwash Containing Extracts of Baccharis dracunculifolia as Agent for the Control of Biofilm: Clinical Evaluation in Humans".}, journal = {TheScientificWorldJournal}, volume = {2016}, number = {}, pages = {8042479}, pmid = {27239550}, issn = {1537-744X}, abstract = {[This corrects the article DOI: 10.1155/2015/712683.].}, } @article {pmid27238815, year = {2016}, author = {Shagaghi, N and Alfred, RL and Clayton, AH and Palombo, EA and Bhave, M}, title = {Anti-biofilm and sporicidal activity of peptides based on wheat puroindoline and barley hordoindoline proteins.}, journal = {Journal of peptide science : an official publication of the European Peptide Society}, volume = {22}, number = {7}, pages = {492-500}, doi = {10.1002/psc.2895}, pmid = {27238815}, issn = {1099-1387}, mesh = {Amino Acid Sequence ; Anti-Bacterial Agents/chemistry/isolation & purification/*pharmacology ; Antimicrobial Cationic Peptides/chemistry/isolation & purification/*pharmacology ; Bacillus subtilis/drug effects/growth & development/ultrastructure ; Biofilms/*drug effects/growth & development ; Hordeum/chemistry/immunology ; Listeria/drug effects/growth & development ; Listeria monocytogenes/drug effects/growth & development ; Microbial Sensitivity Tests ; Plankton/drug effects/growth & development ; Plant Proteins/chemistry/isolation & purification/*pharmacology ; Pseudomonas aeruginosa/drug effects/growth & development ; Spores, Bacterial/*drug effects/growth & development/ultrastructure ; Triticum/chemistry/immunology ; Tryptophan/chemistry ; }, abstract = {The broad-spectrum activity of antimicrobial peptides (AMPs) and low probability of development of host resistance make them excellent candidates as novel bio-control agents. A number of AMPs are found to be cationic, and a small proportion of these are tryptophan-rich. The puroindolines (PIN) are small, basic proteins found in wheat grains with proposed roles in biotic defence of seeds and seedlings. Synthetic peptides based on their unique tryptophan-rich domain (TRD) display antimicrobial properties. Bacterial endospores and biofilms are highly resistant cells, with significant implications in both medical and food industries. In this study, the cationic PIN TRD-based peptides PuroA (FPVTWRWWKWWKG-NH2) and Pina-M (FSVTWRWWKWWKG-NH2) and the related barley hordoindoline (HIN) based Hina (FPVTWRWWTWWKG-NH2) were tested for effects on planktonic cells and biofilms of the common human pathogens including Pseudomonas aeruginosa, Listeria monocytogenes and the non-pathogenic Listeria innocua. All peptides showed significant bactericidal activity. Further, PuroA and Pina-M at 2 × MIC prevented initial biomass attachment by 85-90% and inhibited >90% of 6-h preformed biofilms of all three organisms. However Hina, with a substitution of Lys-9 with uncharged Thr, particularly inhibited Listeria biofilms. The PIN based peptides were also tested against vegetative cells and endospores of Bacillus subtilis. The results provided evidence that these tryptophan-rich peptides could kill B. subtilis even in sporulated state, reducing the number of viable spores by 4 log units. The treated spores appeared withered under scanning electron microscopy. The results establish the potential of these tryptophan-rich peptides in controlling persistent pathogens of relevance to food industries and human health. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.}, } @article {pmid27238459, year = {2016}, author = {Motallebi, M and Jabalameli, F and Asadollahi, K and Taherikalani, M and Emaneini, M}, title = {Spreading of genes encoding enterotoxins, haemolysins, adhesin and biofilm among methicillin resistant Staphylococcus aureus strains with staphylococcal cassette chromosome mec type IIIA isolated from burn patients.}, journal = {Microbial pathogenesis}, volume = {97}, number = {}, pages = {34-37}, doi = {10.1016/j.micpath.2016.05.017}, pmid = {27238459}, issn = {1096-1208}, mesh = {Adhesins, Bacterial/*analysis/genetics ; Biofilms/*growth & development ; Burns/*complications ; Chromosomes, Bacterial ; DNA, Bacterial/genetics ; Enterotoxins/*analysis/genetics ; Genes, Bacterial ; *Genotype ; Hemolysin Proteins/*analysis/genetics ; Humans ; Iran/epidemiology ; Methicillin-Resistant Staphylococcus aureus/classification/isolation & purification/*pathogenicity/*physiology ; Molecular Epidemiology ; Multiplex Polymerase Chain Reaction ; Staphylococcal Skin Infections/epidemiology/*microbiology ; Virulence Factors/analysis/genetics ; }, abstract = {The emergence of antibiotic-resistant Staphylococcus aureus in particular methicillin-resistant S. aureus (MRSA) is an important concern in burn medical centers either in Iran or worldwide. A total of 128 S. aureus isolates were collected from wound infection of burn patients during June 2013 to June 2014. Multiplex-polymerase chain reaction (MPCR) assay was performed for the characterization of the staphylococcal cassette chromosome mec (SCCmec). Genes encoding virulence factors and biofilm were targeted by PCR. Of 128 S. aureus isolates, 77 (60.1%) isolates were MRSA. Fifty four (70.1%) isolates were identified as SCCmec type IIIA. The most frequently detected toxin genes among MRSA isolates with SCCmec type IIIA were sea (64.1%) and hla (51.8%). The rate of coexistence of sea with hla and sea with hla and hlb was 37% and12.9%, respectively. The sec, eta, tst, pvl, hla and hlb genes were not detected in any of the MRSA isolates. The most prevalent genes encoding biofilm was eno, found in 61.1% of isolates, followed by fib and icaA found in 48.1% and 38.8% of the isolates, respectively. The rate of coexistence of fib + eno + icaA + icaD and fib + eno was 20.3% and 9.2%, respectively. The ebps gene was not detected in any of the isolates. In conclusion, our study indicated that the sea, hla, fib and icaA were most frequent genes encoding virulence factors among MRSA with SCCmec type IIIA isolated from burn wound infection. Moreover, the results of this study shows that the rate of coexistence of genes encoding different virulence factor were high.}, } @article {pmid27236754, year = {2016}, author = {Morandi, S and Cremonesi, P and Capra, E and Silvetti, T and Decimo, M and Bianchini, V and Alves, AC and Vargas, AC and Costa, GM and Ribeiro, MG and Brasca, M}, title = {Molecular typing and differences in biofilm formation and antibiotic susceptibilities among Prototheca strains isolated in Italy and Brazil.}, journal = {Journal of dairy science}, volume = {99}, number = {8}, pages = {6436-6445}, doi = {10.3168/jds.2016-10900}, pmid = {27236754}, issn = {1525-3198}, mesh = {Animals ; Anti-Bacterial Agents ; *Biofilms ; Brazil ; Cattle ; Italy ; Mastitis, Bovine/microbiology ; Molecular Typing ; Prototheca/*genetics ; *Random Amplified Polymorphic DNA Technique ; }, abstract = {Bovine mastitis caused by Prototheca is a serious and complex problem that accounts for high economic losses in the dairy industry. The main objective of this study was to identify and characterize at genetic level different Prototheca strains and provide the most complete data about protothecal antibiotic resistance. The study involves 46 isolates from Italian (13 strains) and Brazilian (33 strains) mastitic milk. These strains were identified by multiplex PCR and single strand conformation polymorphism analysis and characterized by randomly amplified polymorphic DNA (RAPD)-PCR. Moreover, biofilm production and antibiotic susceptibility were evaluated. Forty-two strains resulted as Prototheca zopfii genotype 2, whereas 4 isolates could belong to a potential new Prototheca species. The RAPD-PCR, performed with 3 primers (M13, OPA-4, and OPA-18), showed a notable heterogeneity among isolates and grouped the strains according to the species and geographical origin. Biofilm production was species-dependent and P. zopfii genotype 2 strains were classified as strong biofilm producers. In vitro antibiotic susceptibility tests indicated that Prototheca strains were susceptible to antibacterial drugs belonging to aminoglycosides group; the highest activity against Prototheca strains was observed in the case of colistin sulfate, gentamicin, and netilmicin (100% of susceptible strains). It is interesting to note that all the Italian P. zopfii genotype 2 strains showed lower minimum inhibitory concentration values than the Brazilian ones. Nisin showed more efficacy than lysozyme and potassium sorbate, inhibiting 31% of the strains. Results obtained in this study confirmed that RAPD-PCR is a rapid, inexpensive, and highly discriminating tool for Prototheca strains characterization and could give a good scientific contribution for better understanding the protothecal mastitis in dairy herd.}, } @article {pmid27234982, year = {2016}, author = {Liu, H and Wu, YQ and Chen, LP and Gao, X and Huang, HN and Qiu, FL and Wu, DC}, title = {Biofilm-Related Genes: Analyses in Multi-Antibiotic Resistant Acinetobacter Baumannii Isolates From Mainland China.}, journal = {Medical science monitor : international medical journal of experimental and clinical research}, volume = {22}, number = {}, pages = {1801-1807}, pmid = {27234982}, issn = {1643-3750}, mesh = {Acinetobacter baumannii/*genetics/*physiology ; Aged ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; China ; Drug Resistance, Multiple, Bacterial ; Female ; Genes, Bacterial/drug effects ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Respiratory Tract Infections/drug therapy/microbiology ; Retrospective Studies ; }, abstract = {BACKGROUND Acinetobacter baumannii is an important nosocomial pathogen which shows a high level of mortality risk. Several papers have reported biofilm formation as a well-known pathogenic mechanism in A. baumannii infections and exceptional antibiotic resistance. The study aims to explore the potential relationships between biofilm-related genes and antimicrobial resistance. MATERIAL AND METHODS Samples from 122 patients with lower respiratory tract infections of A. baumannii were collected at Fujian Longyan First Hospital from January 2013 to September 2014. A. baumannii was isolated from sputum specimens. Biofilm-related genes including abaI, csuE, ompA, and bla-PER1 were analyzed by PCR. The minimum inhibitory concentration method was used to determine the sensitivity of each strain to antibiotics. RESULTS The clinical manifestations of A. baumannii-induced lower respiratory tract infections lacked specificity. Infected patients were most commonly admitted to intensive care units (54.9%) and frequently had chronic obstructive pulmonary disease (27.0%). The detection rates of abaI and csuE were both 59.8%, and those of ompA and bla-PER1 were 100% and 0%, respectively. After genetic testing, antimicrobial resistance to amikacin, ampicillin/sulbactam, and 14 other types of antimicrobials was higher in abaI- and csuE-positive strains than in abaI- and csuE-negative strains (P<0.05). CONCLUSIONS The findings of our study suggest that abaI- and csuE-positive Acinetobacter baumannii strains are associated with a higher incidence of antibiotic resistance in 14 types of antimicrobials.}, } @article {pmid27234665, year = {2016}, author = {Tawfik, SA and Ibrahim, AA and Talaat, IM and El-Alkamy, SS and Youssef, A}, title = {Role of bacterial biofilm in development of middle ear effusion.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {273}, number = {11}, pages = {4003-4009}, pmid = {27234665}, issn = {1434-4726}, mesh = {Adenoidectomy/methods ; Adenoids/*microbiology/*pathology ; Adolescent ; Biofilms/*growth & development ; Child ; Child, Preschool ; Chronic Disease ; Ear, Middle/pathology ; Egypt ; Female ; Humans ; Hypertrophy/complications/surgery ; Male ; Microscopy, Electron, Scanning ; Middle Ear Ventilation ; Otitis Media with Effusion/*microbiology/surgery ; Sleep Apnea, Obstructive/pathology ; }, abstract = {Biofilms have been implicated in the development of several chronic upper respiratory tract infections. Role of bacterial biofilms has been well studied in the pathogenesis of chronic rhinosinusitis. However, its impact on development of middle ear effusion is still a matter of debate. To study the extent of surface adenoid biofilm and evaluate its role in the pathogenesis of chronic otitis media with effusion in children. The study was carried out on 40 children in Alexandria Main University Hospital between 1 and 16 years of age without sex predilection, who were divided into two groups. The first group (20 children) had otitis media with effusion associated with adenoid hypertrophy, whereas the second group (20 children) had adenoid hypertrophy without middle ear effusion. Adenoidectomy with ventilation tube insertion was done for group 1 cases, whereas, only Adenoidectomy was done for group 2 cases. The samples were processed for the detection of biofilms by scanning electron microscopy. The biofilm formation was graded according to extension. Biofilm formation was detected on all samples for group 1. Adenoids removed from patients with otitis media with effusion had higher-grade biofilm formation than the other group (P 0.0001). No correlation was found between adenoid size and biofilm formation. In pediatric population, adenoid surface biofilm formation may be involved in the pathogenesis otitis media with effusion.}, } @article {pmid27233902, year = {2017}, author = {Graetz, C and Plaumann, A and Wittich, R and Springer, C and Kahl, M and Dörfer, CE and El-Sayed, KF}, title = {Removal of simulated biofilm: an evaluation of the effect on root surfaces roughness after scaling.}, journal = {Clinical oral investigations}, volume = {21}, number = {4}, pages = {1021-1028}, pmid = {27233902}, issn = {1436-3771}, mesh = {*Biofilms ; Dental Plaque/*therapy ; Dental Scaling/*instrumentation ; Equipment Design ; Humans ; In Vitro Techniques ; Manikins ; Surface Properties ; Tooth Root/*microbiology ; Ultrasonic Therapy/*instrumentation ; }, abstract = {BACKGROUND: Despite the development of less invasive devices, a debate exists about the benefits and risks of hand versus powered root surface instrumentation used in supportive periodontal therapy (SPT). The aim of the in vitro study was to differentially compare plaque removal efficacy and root surface roughening of newly developed sonic, ultrasonic scaler, and curettes in the hands of experienced versus less experienced operators.

MATERIALS AND METHODS: Sonic (AIR), ultrasonic devices (TIG), and double-gracey curettes (GRA) were utilized by seven experienced (EO) and four less experienced operators (LO) for root surface instrumentation of standardized plastic teeth on manikins' heads in a randomized sequence. The proportion of residual simulated plaque (RSP area in %) was planimetrically assessed, and the average root surface roughness produced (Ra and ∆Ra in μm) was measured by a precision profilometer.

RESULTS: The uninstrumented root surfaces showed a Ra of (median (Q25/Q75)) 1.00 μm (0.83/1.16). Following instrumentation, EO left significantly less RSP than LO regardless of the used instruments (20.00 % (10.00/34.00) vs. 26.00 % (12.00/44.00) p < 0.001), whereas the ∆Ra values (0.29 μm (-0.04/0.96) vs. 0.35 μm (-0.04/1.01), p = 0.237) failed to show significant differences. The surface roughness was higher with GRA followed by AIR then TIG regardless of operators' experience (p < 0.001).

CONCLUSION: Within the limits of the present study, the sonic device was most efficient in plaque removal, while the ultrasonic device produced the least surface roughness.

CLINICAL RELEVANCE: All three tested instruments seem effective in the mechanical root debridement during SPT, whereat the ultrasonic device show the smoothest root surface of all.}, } @article {pmid27232358, year = {2016}, author = {Ferreira Ribeiro, C and Cogo-Müller, K and Franco, GC and Silva-Concílio, LR and Sampaio Campos, M and de Mello Rode, S and Claro Neves, AC}, title = {Initial oral biofilm formation on titanium implants with different surface treatments: An in vivo study.}, journal = {Archives of oral biology}, volume = {69}, number = {}, pages = {33-39}, doi = {10.1016/j.archoralbio.2016.05.006}, pmid = {27232358}, issn = {1879-1506}, mesh = {Acid Etching, Dental/methods ; Bacterial Adhesion ; Biofilms/*growth & development ; Dental Implants/*microbiology ; Electrochemical Techniques ; Humans ; Lasers ; Materials Testing ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Streptococcus oralis/physiology ; Surface Properties ; *Titanium ; }, abstract = {OBJECTIVE: The aim of this study was to examine in vivo the initial bacterial adhesion on titanium implants with different surface treatments.

DESIGN: Ten subjects wore oral splints containing machined pure titanium disks (Ti-M), acid-etched titanium (Ti-AE) and anodized and laser irradiated disks (Ti-AL) for 24h. After this period, disks were removed from the splints and adherent bacteria were quantified by an enzymatic assay to assess total viable bacteria and by Real Time PCR to evaluate total bacteria and Streptococcus oralis levels. Additionally, the initial adherent microorganisms were visualized by scanning electron microscopy (SEM). Titanium surface morphology was verified using SEM, and roughness was evaluated by profilometer analysis.

RESULTS: Regarding titanium surface roughness, Ti-AL (1.423±0.397) showed significantly higher Ra values than did Ti-M (0.771±0.182) and Ti-AE (0.735±0.196) (p<0.05, ANOVA - Tahame). Ti-AE and Ti-AL presented roughened micro-structure surfaces characterized by open pores, whereas Ti-M showed long grooves alternating with planed areas. Comparing the Ti-M, Ti-AE and Ti-AL groups for viable bacteria (MTT assay), total bacteria and S. oralis quantification (qPCR), no significant differences were observed among these three groups (p>0.05, ANOVA - Tahame). SEM images showed similar bacterial adhesion on the three titanium surfaces, predominantly characterized by cocci and several bacilli, indicating an initial colonization of the oral biofilm.

CONCLUSION: In conclusion, roughness and microtopography did not stimulate initial biofilm formation on titanium surfaces with different surface treatments.}, } @article {pmid27231279, year = {2016}, author = {Lashua, LP and Melvin, JA and Deslouches, B and Pilewski, JM and Montelaro, RC and Bomberger, JM}, title = {Engineered cationic antimicrobial peptide (eCAP) prevents Pseudomonas aeruginosa biofilm growth on airway epithelial cells.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {71}, number = {8}, pages = {2200-2207}, pmid = {27231279}, issn = {1460-2091}, support = {P30 DK072506/DK/NIDDK NIH HHS/United States ; R01 HL123771/HL/NHLBI NIH HHS/United States ; }, mesh = {Anti-Infective Agents/*pharmacology ; Antimicrobial Cationic Peptides/genetics/*pharmacology ; Biofilms/*drug effects/growth & development ; Cell Line ; Coculture Techniques ; Epithelial Cells/*microbiology ; Humans ; Protein Engineering ; Pseudomonas aeruginosa/*drug effects/physiology ; Recombinant Proteins/genetics/*pharmacology ; }, abstract = {OBJECTIVES: Chronic infections with the opportunistic pathogen Pseudomonas aeruginosa are responsible for the majority of the morbidity and mortality in patients with cystic fibrosis (CF). While P. aeruginosa infections may initially be treated successfully with standard antibiotics, chronic infections typically arise as bacteria transition to a biofilm mode of growth and acquire remarkable antimicrobial resistance. To address the critical need for novel antimicrobial therapeutics that can effectively suppress chronic bacterial infections in challenging physiological environments, such as the CF lung, we have rationally designed a de novo engineered cationic antimicrobial peptide, the 24-residue WLBU2, with broad-spectrum antibacterial activity for pan-drug-resistant P. aeruginosa in liquid culture. In the current study, we tested the hypothesis that WLBU2 also prevents P. aeruginosa biofilm growth.

METHODS: Using abiotic and biotic biofilm assays, co-culturing P. aeruginosa with polarized human airway epithelial cells, we examined the ability of WLBU2 to prevent biofilm biogenesis alone and in combination with currently used antibiotics.

RESULTS: We observed a dose-dependent reduction in biofilm growth on an abiotic surface and in association with CF airway epithelial cells. WLBU2 prevented P. aeruginosa biofilm formation when co-cultured with mucus-producing primary human CF airway epithelial cells and using CF clinical isolates of P. aeruginosa, even at low pH and high salt conditions that mimic the CF airway. When used in combination, WLBU2 significantly increases killing by the commonly used antibiotics tobramycin, ciprofloxacin, ceftazidime and meropenem.

CONCLUSIONS: While other studies have demonstrated the ability of natural and synthetic antimicrobial peptides to prevent abiotic bacterial biofilm formation, the current studies for the first time demonstrate the effective peptide treatment of a biotic bacterial biofilm in a setting similar to the CF airway, and without negative effects on human airway epithelial cells, thus highlighting the unique potential of this engineered cationic antimicrobial peptide for treatment of human respiratory infections.}, } @article {pmid27230628, year = {2016}, author = {Bezek, K and Kurinčič, M and Knauder, E and Klančnik, A and Raspor, P and Bucar, F and Smole Možina, S}, title = {Attenuation of Adhesion, Biofilm Formation and Quorum Sensing of Campylobacter jejuni by Euodia ruticarpa.}, journal = {Phytotherapy research : PTR}, volume = {30}, number = {9}, pages = {1527-1532}, doi = {10.1002/ptr.5658}, pmid = {27230628}, issn = {1099-1573}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Campylobacter jejuni/*drug effects ; Evodia/*chemistry ; Fruit/*chemistry ; Quorum Sensing/*physiology ; }, abstract = {Thermophilic campylobacters are a major cause of bacterial food-borne diarrhoeal disease. Adherence and biofilm formation are key elements of Campylobacter jejuni persistence in unfavourable environmental conditions. The phytochemical analysis of Euodia ruticarpa fruit ethanol solution extract (EREE) indicated that the major compounds were evodiamine (1), rutaecarpine (2) and evocarpine (9). E. ruticarpa fruit ethanol solution extract, compounds 1 and 2 as well as a mixture of quinolinone alkaloids with 41.7% of 9 were tested for antibacterial, antibiofilm and antiquorum sensing activities against C. jejuni. Minimal inhibitory concentrations varied from 64 to 1024 µg/mL. A mutant strain that lacks the functional gene coding for the CmeB efflux pump protein was the most susceptible. Interestingly, in addition to the wild-type (NCTC 11168) and cmeB mutant, also a mutant that lacks autoinducer-2 production (luxS) was able to adhere (1 h) and to produce a biofilm (24, 48 and 72 h). The subinhibitory concentrations of all preparations at least partly inhibited C. jejuni adhesion and biofilm formation with the most visible effect of the quinolinone alkaloid fraction. Using a Vibrio harveyi luminescence assay, the inhibition of autoinducer-2 production was observed in the wild-type and cmeB mutant after 48 h with the most visible effect of EREE and its fraction Q. Copyright © 2016 John Wiley & Sons, Ltd.}, } @article {pmid27229727, year = {2017}, author = {Nagata, ME and Delbem, AC and Hall, KB and Buzalaf, MA and Pessan, JP}, title = {Fluoride and calcium concentrations in the biofilm fluid after use of fluoridated dentifrices supplemented with polyphosphate salts.}, journal = {Clinical oral investigations}, volume = {21}, number = {3}, pages = {831-837}, pmid = {27229727}, issn = {1436-3771}, mesh = {Adult ; Biofilms/*drug effects ; Calcium/*analysis ; Cross-Over Studies ; Dentifrices/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Double-Blind Method ; Female ; Fluorides/*analysis ; Glycerophosphates/chemistry/*pharmacology ; Humans ; Male ; Polyphosphates/chemistry/*pharmacology ; Toothbrushing ; }, abstract = {OBJECTIVES: The present study evaluated fluoride (F) and calcium (Ca) concentrations in the biofilm fluid formed in situ under cariogenic challenge after using F dentifrices supplemented or not with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP).

METHODS: Volunteers (n = 12) were randomly divided into 5 groups according to the toothpastes used: placebo (without F, CaGP or TMP), 1100 ppm F (1100F) and low-fluoride dentifrice (LFD, 550 ppm F) with no supplementation (550F) or supplemented with 1 % TMP (550F-TMP) or 0.25 % CaGP (550F-CaGP). In each phase, volunteers wore palatal appliances containing 4 bovine enamel blocks. Cariogenic challenge was performed with 30 % sucrose solution, 6 times/day. On the morning of the eigth day, biofilm samples were collected 12 h and 1 h after brushing and cariogenic challenge. F and Ca analyses in the biofilm fluid were performed with the inverted electrode after buffering with TISAB III and using the Arsenazo III method, respectively. Data were submitted to two-way ANOVA (repeated measures) and Student-Newman-Keuls test (p < 0.05).

RESULTS: A dose-response relationship was verified between F concentrations in the dentifrices and in the biofilm fluid. Significant differences were observed among placebo, 550F, and 1100F only 1 h after brushing, without statistical differences among 550F, 550F-TMP, and 550F-CaGP. No defined trend was observed among the groups regarding Ca concentrations, with the highest values seen for placebo and 550F-CaGP.

CONCLUSION: The anticaries effect of LFDs supplemented with CaGP or TMP cannot be related to an increased availability of F and Ca in the biofilm fluid.

CLINICAL SIGNIFICANCE: The better performance of LFDs containing CaGP or TMP shown in previous studies should be attributed to their ability to interact with tooth enamel and with the biofilm, rather to their effect on the biofilm fluid.}, } @article {pmid27227309, year = {2016}, author = {Paharik, AE and Horswill, AR}, title = {The Staphylococcal Biofilm: Adhesins, Regulation, and Host Response.}, journal = {Microbiology spectrum}, volume = {4}, number = {2}, pages = {}, pmid = {27227309}, issn = {2165-0497}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Bacterial Adhesion/drug effects/physiology ; Biofilms/drug effects/*growth & development ; Chronic Disease ; Host-Pathogen Interactions ; Humans ; Staphylococcal Infections/microbiology ; Staphylococcus/drug effects/*physiology ; Staphylococcus aureus/drug effects/physiology ; Staphylococcus epidermidis/drug effects/physiology ; }, abstract = {The staphylococci comprise a diverse genus of Gram-positive, nonmotile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. Staphylococcus aureus and Staphylococcus epidermidis are major sources of hospital-acquired infections and are the most common causes of surgical site infections and medical device-associated bloodstream infections. The ability of staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device infections, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the staphylococcus genus and how this mode of growth impacts the host.}, } @article {pmid27226465, year = {2016}, author = {Hathroubi, S and Beaudry, F and Provost, C and Martelet, L and Segura, M and Gagnon, CA and Jacques, M}, title = {Impact of Actinobacillus pleuropneumoniae biofilm mode of growth on the lipid A structures and stimulation of immune cells.}, journal = {Innate immunity}, volume = {22}, number = {5}, pages = {353-362}, doi = {10.1177/1753425916649676}, pmid = {27226465}, issn = {1753-4267}, mesh = {Actinobacillus Infections/*immunology/microbiology ; Actinobacillus pleuropneumoniae/growth & development/*immunology ; Animals ; Biofilms/*growth & development ; Cell Proliferation ; Cells, Cultured ; Chromatography, High Pressure Liquid ; Cytokines/metabolism ; Drug Resistance, Microbial ; Immune Evasion ; Immunity, Innate ; Inflammation Mediators/metabolism ; Leukocytes, Mononuclear/*immunology/microbiology ; Lipid A/*chemistry/immunology ; Macrophages, Alveolar/*immunology/microbiology ; Mass Spectrometry ; Sus scrofa ; }, abstract = {Actinobacillus pleuropneumoniae (APP), the etiologic agent of porcine pleuropneumonia, forms biofilms on biotic and abiotic surfaces. APP biofilms confers resistance to antibiotics. To our knowledge, no studies have examined the role of APP biofilm in immune evasion and infection persistence. This study was undertaken to (i) investigate biofilm-associated LPS modifications occurring during the switch to biofilm mode of growth; and (ii) characterize pro-inflammatory cytokines expression in porcine pulmonary alveolar macrophages (PAMs) and proliferation in porcine PBMCs challenged with planktonic or biofilm APP cells. Extracted lipid A samples from biofilm and planktonic cultures were analyzed by HPLC high-resolution, accurate mass spectrometry. Biofilm cells displayed significant changes in lipid A profiles when compared with their planktonic counterparts. Furthermore, in vitro experiments were conducted to examine the inflammatory response of PAMs exposed to UV-inactivated APP grown in biofilm or in suspension. Relative mRNA expression of pro-inflammatory genes IL1, IL6, IL8 and MCP1 decreased in PAMs when exposed to biofilm cells compared to planktonic cells. Additionally, the biofilm state reduced PBMCs proliferation. Taken together, APP biofilm cells show a weaker ability to stimulate innate immune cells, which could be due, in part, to lipid A structure modifications.}, } @article {pmid27226289, year = {2017}, author = {Ficarra, FA and Grandellis, C and Galván, EM and Ielpi, L and Feil, R and Lunn, JE and Gottig, N and Ottado, J}, title = {Xanthomonas citri ssp. citri requires the outer membrane porin OprB for maximal virulence and biofilm formation.}, journal = {Molecular plant pathology}, volume = {18}, number = {5}, pages = {720-733}, pmid = {27226289}, issn = {1364-3703}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/growth & development ; Polysaccharides, Bacterial/metabolism ; Porins/genetics/metabolism ; Virulence ; Xanthomonas/*metabolism/*pathogenicity ; }, abstract = {Xanthomonas citri ssp. citri (Xcc) causes canker disease in citrus, and biofilm formation is critical for the disease cycle. OprB (Outer membrane protein B) has been shown previously to be more abundant in Xcc biofilms compared with the planktonic state. In this work, we showed that the loss of OprB in an oprB mutant abolishes bacterial biofilm formation and adherence to the host, and also compromises virulence and efficient epiphytic survival of the bacteria. Moreover, the oprB mutant is impaired in bacterial stress resistance. OprB belongs to a family of carbohydrate transport proteins, and the uptake of glucose is decreased in the mutant strain, indicating that OprB transports glucose. Loss of OprB leads to increased production of xanthan exopolysaccharide, and the carbohydrate intermediates of xanthan biosynthesis are also elevated in the mutant. The xanthan produced by the mutant has a higher viscosity and, unlike wild-type xanthan, completely lacks pyruvylation. Overall, these results suggest that Xcc reprogrammes its carbon metabolism when it senses a shortage of glucose input. The participation of OprB in the process of biofilm formation and virulence, as well as in metabolic changes to redirect the carbon flux, is discussed. Our results demonstrate the importance of environmental nutrient supply and glucose uptake via OprB for Xcc virulence.}, } @article {pmid27226212, year = {2016}, author = {Neves, PA and Ribeiro, CC and Tenuta, LM and Leitão, TJ and Monteiro-Neto, V and Nunes, AM and Cury, JA}, title = {Breastfeeding, Dental Biofilm Acidogenicity, and Early Childhood Caries.}, journal = {Caries research}, volume = {50}, number = {3}, pages = {319-324}, doi = {10.1159/000445910}, pmid = {27226212}, issn = {1421-976X}, mesh = {Analysis of Variance ; Biofilms/*growth & development ; Breast Feeding/*adverse effects ; Cross-Over Studies ; Dental Caries/*epidemiology/*etiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Infant ; Lactobacillus/isolation & purification ; Male ; Microelectrodes ; Milk, Human/*chemistry ; Saliva/microbiology ; Streptococcus mutans/isolation & purification ; Sucrose/chemistry ; Time Factors ; Tooth, Deciduous/*microbiology ; }, abstract = {AIM: This study evaluated the acidogenicity of human milk by the dental biofilms of children with and without early childhood caries (ECC).

METHOD: Biofilms of 16 children (7 with ECC; 9 caries free) were exposed to human milk or 10% sucrose solution in the crossover design, and the biofilm pH was determined.

RESULTS: Breastfeeding did not provoke a decrease in biofilm pH, irrespective of the children's caries status, whereas sucrose decreased the pH for both groups. In addition, higher x0394;pH5min (pH variation occurring at 5 min) was observed in the biofilms of ECC children (p < 0.05). The results suggest that breastfeeding may not contribute to ECC.}, } @article {pmid27226009, year = {2016}, author = {Reyes-Pérez, A and Vargas, Mdel C and Hernández, M and Aguirre-von-Wobeser, E and Pérez-Rueda, E and Encarnacion, S}, title = {Transcriptomic analysis of the process of biofilm formation in Rhizobium etli CFN42.}, journal = {Archives of microbiology}, volume = {198}, number = {9}, pages = {847-860}, doi = {10.1007/s00203-016-1241-5}, pmid = {27226009}, issn = {1432-072X}, mesh = {4-Butyrolactone/analogs & derivatives/metabolism ; Biofilms/*growth & development ; DNA, Bacterial/analysis ; *Gene Expression Regulation, Bacterial ; Microarray Analysis ; RNA, Bacterial/analysis ; Rhizobium etli/*genetics/physiology ; Transcriptome/*physiology ; }, abstract = {Organisms belonging to the genus Rhizobium colonize leguminous plant roots and establish a mutually beneficial symbiosis. Biofilms are structured ecosystems in which microbes are embedded in a matrix of extracellular polymeric substances, and their development is a multistep process. The biofilm formation processes of R. etli CFN42 were analyzed at an early (24-h incubation) and mature stage (72 h), comparing cells in the biofilm with cells remaining in the planktonic stage. A genome-wide microarray analysis identified 498 differentially regulated genes, implying that expression of ~8.3 % of the total R. etli gene content was altered during biofilm formation. In biofilms-attached cells, genes encoding proteins with diverse functions were overexpressed including genes involved in membrane synthesis, transport and chemotaxis, repression of flagellin synthesis, as well as surface components (particularly exopolysaccharides and lipopolysaccharides), in combination with the presence of activators or stimulators of N-acyl-homoserine lactone synthesis This suggests that R. etli is able to sense surrounding environmental conditions and accordingly regulate the transition from planktonic and biofilm growth. In contrast, planktonic cells differentially expressed genes associated with transport, motility (flagellar and twitching) and inhibition of exopolysaccharide synthesis. To our knowledge, this is the first report of nodulation and nitrogen assimilation-related genes being involved in biofilm formation in R. etli. These results contribute to the understanding of the physiological changes involved in biofilm formation by bacteria.}, } @article {pmid27224556, year = {2016}, author = {Nunes, AC and Longo, PL and Mayer, MP}, title = {Influence of Aae Autotransporter Protein on Adhesion and Biofilm Formation by Aggregatibacter actinomycetemcomitans.}, journal = {Brazilian dental journal}, volume = {27}, number = {3}, pages = {255-260}, doi = {10.1590/0103-6440201600260}, pmid = {27224556}, issn = {1806-4760}, mesh = {Aggregatibacter actinomycetemcomitans/genetics/*physiology ; Bacterial Adhesion/*physiology ; Bacterial Proteins/genetics/*physiology ; Biofilms ; Gene Knockdown Techniques ; Hydrophobic and Hydrophilic Interactions ; Membrane Transport Proteins/genetics/*physiology ; }, abstract = {The periodontopathogen Aggregatibacter actinomycetemcomitans colonizes oral cavity by binding to and invading epithelial cells as well as by participating in biofilms formed on hard surfaces. Aae, an autotransporter protein, is implicated in bacterial adhesion to epithelial cells. Due to the multiple functions of bacterial autotransporter proteins, this study aimed to evaluate the role of aae in A. actinomycetemcomitans ability to adhere to both saliva-coated hydroxyapatite (SHA) and biofilm. An aae null mutant was constructed. Its hydrophobic properties as well as its ability to adhere to epithelial cells, SHA and to form biofilm were evaluated and compared with the parental strain, A. actinomycetemcomitans VT1169. The aae null mutant showed reduced hydrophobicity, as well as decreased binding to SHA and biofilm formation compared to the parental strain. These data suggest that aae mediates A. actinomycetemcomitans adhesion to epithelial cells and may be involved in biofilm formation and interaction with adsorbed salivary proteins.}, } @article {pmid27223617, year = {2016}, author = {Zhou, H and Luo, C and Fang, X and Xiang, Y and Wang, X and Zhang, R and Chen, Z}, title = {Loss of GltB Inhibits Biofilm Formation and Biocontrol Efficiency of Bacillus subtilis Bs916 by Altering the Production of γ-Polyglutamate and Three Lipopeptides.}, journal = {PloS one}, volume = {11}, number = {5}, pages = {e0156247}, pmid = {27223617}, issn = {1932-6203}, mesh = {Bacillus subtilis/genetics/*physiology ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Computational Biology/methods ; Gene Expression Profiling/methods ; Lipopeptides/*metabolism/pharmacology ; Mutation ; Oryza/microbiology ; Peptides, Cyclic/metabolism/pharmacology ; Plant Diseases/prevention & control ; Polyglutamic Acid/*analogs & derivatives/metabolism ; }, abstract = {AIMS: This study examined the contribution of GltB on biofilm formation and biocontrol efficiency of B. subtilis Bs916.

METHODS AND RESULTS: The gltB gene was identified through a biofilm phenotype screen and a bioinformatics analysis of serious biofilm formation defects, and then a gltB single knockout mutant was constructed using homologous recombination. This mutant demonstrated severe deficits in biofilm formation and colonisation along with significantly altered production ofγ-polyglutamate (γ-PGA) and three lipopeptide antibiotics (LPs) as measured by a transcriptional analysis of both the wild type B. subtilis Bs916 and the gltB mutant. Consequently, the mutant strain retained almost no antifungal activity against Rhizoctonia solani and exhibited decreased biocontrol efficiency against rice sheath blight. Very few gltB mutant cells colonised the rice stem, and they exhibited no significant nutrient chemotaxis compared to the wild type B. subtilis Bs916. The mechanism underlying these deficits in the gltB mutant appears to be decreased significantly in production of γ-PGA and a reduction in the production of both bacillomycin L and fengycin. Biofilm restoration of gltB mutant by additionγ-PGA in the EM medium demonstrated that biofilm formation was able to restore significantly at 20 g/L.

CONCLUSIONS: GltB regulates biofilm formation by altering the production ofγ-PGA, the LPs bacillomycin L and fengcin and influences bacterial colonisation on the rice stem, which consequently leads to poor biocontrol efficiency against rice sheath blight.

This is the first report of a key regulatory protein (GltB) that is involved in biofilm regulation and its regulation mechanism and biocontrol efficiency by B. subtilis.}, } @article {pmid27223133, year = {2016}, author = {Botelho, JN and Villegas-Salinas, M and Troncoso-Gajardo, P and Giacaman, RA and Cury, JA}, title = {Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm - caries model.}, journal = {Brazilian oral research}, volume = {30}, number = {1}, pages = {}, doi = {10.1590/1807-3107BOR-2016.vol30.0052}, pmid = {27223133}, issn = {1807-3107}, mesh = {Animals ; Biofilms/*growth & development ; Cariogenic Agents/*chemistry ; Cattle ; Colony Count, Microbial ; Dental Enamel/*chemistry/microbiology ; Dentin/*chemistry/microbiology ; Dietary Sucrose/*chemistry ; Humans ; Reference Values ; Saliva/chemistry/microbiology ; Starch/*chemistry ; Statistics, Nonparametric ; Streptococcus mutans/growth & development ; Time Factors ; Tooth Demineralization/*etiology/microbiology ; Young Adult ; }, abstract = {Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containing 10% saliva. They were exposed (8 times/day) to one of the following treatments: 0.9% NaCl (negative control), 1% starch, 10% sucrose, or 1% starch and 10% sucrose (starch + sucrose). To simulate the effect of human salivary amylase on the starch metabolization, the biofilms were pretreated with saliva before each treatment and saliva was also added to the culture medium. Acidogenicity of the biofilm was estimated by evaluating (2 times/day) the culture medium pH. After 4 (dentine) or 5 (enamel) days of growth, biofilms (n = 9) were individually collected, and the biomass, viable microorganism count, and polysaccharide content were quantified. Dentine and enamel demineralization was assessed by determining the percentage of surface hardness loss. Biofilms exposed to starch + sucrose were more acidogenic and caused higher demineralization (p < 0.0001) on either enamel or dentine than those exposed to each carbohydrate alone. The findings suggest that starch increases the cariogenic potential of sucrose.}, } @article {pmid27222487, year = {2016}, author = {Ramachandran, G and Aheto, K and Shirtliff, ME and Tennant, SM}, title = {Poor biofilm-forming ability and long-term survival of invasive Salmonella Typhimurium ST313.}, journal = {Pathogens and disease}, volume = {74}, number = {5}, pages = {}, pmid = {27222487}, issn = {2049-632X}, support = {U54 AI057168/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/drug effects/*growth & development ; Disinfectants/pharmacology ; *Microbial Viability ; Phenotype ; Salmonella Infections/*microbiology ; Salmonella typhimurium/classification/drug effects/*physiology ; Sodium Hypochlorite/pharmacology ; }, abstract = {Salmonella enterica serovar Typhimurium, an enteric pathogen that causes a self-limiting gastroenteritis, forms biofilms on different surfaces. In sub-Saharan Africa, Salmonella Typhimurium of a novel sequence type (ST) 313 was identified and produces septicemia in the absence of gastroenteritis. No animal reservoir has been identified, and it is hypothesized that transmission occurs via human to human. In this study, we show that invasive Salmonella Typhimurium ST313 strains from Mali are poor biofilm producers compared to Salmonella Typhimurium ST19 strains, which are found worldwide and are known to be associated with gastroenteritis. We evaluated biofilms using crystal violet staining, examination of the red, dry and rough morphotype, pellicle formation and a continuous flow system. One month-old Salmonella Typhimurium ST19 colonies survived in the absence of exogenous nutrients and were highly resistant to sodium hypochlorite treatment compared to Salmonella Typhimurium ST313. This study for the first time demonstrates the comparative biofilm-forming ability and long-term survival of clinical Salmonella Typhimurium ST19 and ST313 isolates. Salmonella Typhimurium ST19 strains are strong biofilm producers and can survive desiccation compared to Salmonella Typhimurium ST313 that form weak biofilms and survive poorly following desiccation. Our data suggest that like Salmonella Typhi, Salmonella Typhimurium ST313 lack mechanisms that allow it to persist in the environment.}, } @article {pmid27220400, year = {2016}, author = {Yu, Q and Li, J and Zhang, Y and Wang, Y and Liu, L and Li, M}, title = {Inhibition of gold nanoparticles (AuNPs) on pathogenic biofilm formation and invasion to host cells.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {26667}, pmid = {27220400}, issn = {2045-2322}, mesh = {*Antifungal Agents/chemistry/pharmacology ; *Biofilms/drug effects/growth & development ; Candida albicans/*physiology ; Dental Pulp/*microbiology ; *Gold/chemistry/pharmacology ; Humans ; *Metal Nanoparticles/chemistry/therapeutic use ; Pseudomonas aeruginosa/*physiology ; Stem Cells/*microbiology ; }, abstract = {Owing to the growing infectious diseases caused by eukaryotic and prokaryotic pathogens, it is urgent to develop novel antimicrobial agents against clinical pathogenic infections. Biofilm formation and invasion into the host cells are vital processes during pathogenic colonization and infection. In this study, we tested the inhibitory effect of Au nanoparticles (AuNPs) on pathogenic growth, biofilm formation and invasion. Interestingly, although the synthesized AuNPs had no significant toxicity to the tested pathogens, Candida albicans and Pseudomonas aeruginosa, the nanoparticles strongly inhibited pathogenic biofilm formation and invasion to dental pulp stem cells (DPSCs). Further investigations revealed that AuNPs abundantly bound to the pathogen cells, which likely contributed to their inhibitory effect on biofilm formation and invasion. Moreover, treatment of AuNPs led to activation of immune response-related genes in DPSCs, which may enhance the activity of host immune system against the pathogens. Zeta potential analysis and polyethylene glycol (PEG)/polyethyleneimine (PEI) coating tests further showed that the interaction between pathogen cells and AuNPs is associated with electrostatic attractions. Our findings shed novel light on the application of nanomaterials in fighting against clinical pathogens, and imply that the traditional growth inhibition test is not the only way to evaluate the drug effect during the screening of antimicrobial agents.}, } @article {pmid27220195, year = {2016}, author = {Metcalf, DG and Bowler, PG and Hurlow, J}, title = {A clinical algorithm for wound biofilm identification.}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {73-79}, pmid = {27220195}, issn = {1330-0164}, mesh = {*Algorithms ; *Biofilms ; *Decision Support Systems, Clinical ; Humans ; *Wound Infection/diagnosis/microbiology ; }, abstract = {Recognition of the existence of biofilm in chronic wounds is increasing among wound care practitioners, and a growing body of evidence indicates that biofilm contributes significantly to wound recalcitrance. While clinical guidelines regarding the involvement of biofilm in human bacterial infections have been proposed, there remains uncertainty and lack of guidance towards biofilm presence in wounds. The intention of this report is to collate knowledge and evidence of the visual and indirect clinical indicators of wound biofilm, and propose an algorithm designed to facilitate clinical recognition of biofilm and subsequent wound management practices.}, } @article {pmid27220194, year = {2016}, author = {Lipozencić, J and Tunuković, S and Skrlin, J and Kulisić, SM and Rucigaj, TP and Tepes, NK}, title = {CONCLUSIVE NOTES ON BIOFILM AND ANTIMICROBIAL DRESSINGS.}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {72, 71}, pmid = {27220194}, issn = {1848-8897}, } @article {pmid27220191, year = {2016}, author = {Rucigaj, TP}, title = {BIOFILM AND OUR CLINICAL EXPERIENCE.}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {57-59}, pmid = {27220191}, issn = {1330-0164}, mesh = {Anti-Infective Agents, Local/*therapeutic use ; *Bandages ; *Biofilms ; *Debridement ; Humans ; *Wound Infection/microbiology/therapy ; }, abstract = {Bacteria organized in biofilms are insensitive to the usual treatment with dressings or antibiotics. Most successful is surgical debridement to remove their colonies, but this option may not be possible in all environments. Dressings with silver and other antiseptics are often the only tools available to nurses at patient homes or to dermatologists at outpatient clinics. In our clinical studies conducted several years ago, we demonstrated that dressings with antiseptics were an effective tool in daily clinical practice to remove bacteria/biofilms from chronic wounds.}, } @article {pmid27220189, year = {2016}, author = {Tunuković, S}, title = {[THE ROLE OF WOUND DRESSING IN BIOFILM DESTRUCTION AND REFORMATION].}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {43-47}, pmid = {27220189}, issn = {1330-0164}, mesh = {*Bandages ; *Biofilms ; Chronic Disease ; Humans ; *Ulcer/microbiology/therapy ; }, abstract = {Application of supportive wound dressing is an important segment for successful result of modern treatment of chronic ulcers. The right choice of dressing is the key to faster, better, and ultimately more cost-effective treatment outcome. Due to the extremely large number of generic types and variants, the main element for proper dressing selection is to know the mechanisms of action and clinical evidence of the effectiveness because of many local factors that delay ulcer healing. The advent of wound dressing that is efficient at the three clinically identified key local factors that largely impede the healing of ulcers, i.e. exudate, infection and biofilm, has made a significant step forward in the creation of optimal conditions for faster healing of chronic ulcers. The complexity of the effects of new technologies, which integrate hidrofiber technology and Ag + technology, provides effective antimicrobial control while at the same time preventing biofilm reformation.}, } @article {pmid27220188, year = {2016}, author = {Kucisec-Tepes, N}, title = {[THE ROLE OF ANTISEPTICS AND STRATEGY OF BIOFILM REMOVAL IN CHRONIC WOUND].}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {33-42}, pmid = {27220188}, issn = {1330-0164}, mesh = {Anti-Infective Agents, Local/pharmacology/therapeutic use ; Biofilms/*drug effects ; Chronic Disease ; Debridement ; Humans ; Pseudomonas aeruginosa ; Wound Healing/drug effects ; *Wound Infection/microbiology/therapy ; }, abstract = {Chronic wound does not heal within the expected time frame because it remains in the inflammation phase of healing. The reason for this is the presence of necrotic tissue and a large number of microorganisms, primarily bacteria that secrete the biofilm, along with ischemia, hypoxia and edema. Biofilm is present in 90% of chronic wounds and 6% of the acute ones. Biofilm is a corporative association of microbes which adhere to the surface of the wound, guided by quorum sensing molecules. The association is surrounded by a moisturizing matrix of extracellular polymeric substances (slime) which protect the microbes from the impact of antibiotics, antiseptics, macro-organism defense and stress. Biofilm is the primary cause of the wound chronicity because it causes permanent inflammation, delayed granulation tissue formation and migration of epithelium cells, thus providing a reservoir of microbes that lead to infection of the chronic wound. The aim of good clinical practice is to enable healing of a chronic wound within the expected time frame. In order to achieve this aim, it is necessary to reduce and thoroughly remove the biofilm from the wound and prevent its reappearance. This is achieved by the application of active anti-biofilm compounds and procedures that disintegrate the quorum sensing molecules, degrade the extracellular polymeric substances and block adherence to the surfaces. Recent researches have shown that the application of antiseptics is effective in the prevention of infection and is a support to targeted treatment. However, the fact is that only some antiseptics are applicable to chronic wounds and can have an impact on biofilms of the primary infective agents such as Staphylococcus spp., Streptococcus spp., and Pseudomonas aeruginosa. Effective antiseptics are octenidine dihydrochloride, polyhexanides, povidone and cadexomer iodine, nanocrystal silver and Manuka-type honey. Immobile biofilm is a persistent problem of chronic and chronic infected wounds. In fact, there is no isolated therapeutic procedure or an individual antiseptic that can fully destroy the biofilm. For this reason, modern strategy in the management of chronic wound applies a multimodal approach which combines mechanical-chemical procedures such as debridement, antiseptics, and antimicrobial supportive compresses. Debridement creates a therapeutic 'window' for the action of antiseptics and antibiotics in a 72-hour period, which enables removal of the biofilm and active destruction of the sessile and planktonic bacteria. This approach also prevents de novo formation of the biofilm. The above procedures must be intensively repeated, and antiseptics and supportive compresses changed, depending on the phase of the wound bed and comorbidity factors in the patient. The results of clinical studies show that only such a proactive approach to chronic wound enables achievement of healing within the expected period of time.}, } @article {pmid27220187, year = {2016}, author = {Skrlin, J}, title = {[IMPACT OF BIOFILM ON HEALING AND A METHOD FOR IDENTIFYING IT IN THE WOUND].}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {29-32}, pmid = {27220187}, issn = {1330-0164}, mesh = {Bacteria/*isolation & purification ; *Bacterial Typing Techniques ; *Biofilms ; Humans ; *Wound Healing ; Wound Infection/diagnosis/*microbiology/therapy ; }, abstract = {The skin microbiome is the aggregate of microorganisms that reside on the surface and in deep layers of the skin. Skin is colonized by bacteria, fungi, viruses and mites, maintaining a balance. Disruption in the ecosystem results in skin infections. Chronic wounds in diabetics, elderly and immobile individuals are at risk of skin organisms to invade and become pathogenic upon breach of the skin barrier. The bacteria of the skin microbiome may contribute to delayed healing and persistent inflammation. Staphylococcus epidermidis is an invasive skin organism that causes infection, i.e. hospital acquired infection (HAl) on medical devices and form biofilm. At the most basic level, biofilm can be described as bacteria embedded in a thick, slimy barrier of sugars and proteins. The biofilm barrier protects the microorganisms from external threats. Biofilms provide a reservoir of potentially infectious microorganisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic inflammatory condition is increasingly being recognized. Particular research interest exists in the association of biofilms with wound infection and non-healing, i.e. chronic wounds. There is now strong evidence that biofilm is present in the majority of chronic wounds. Specialized microscopic techniques used since 2008 have allowed several research groups to demonstrate that 60% to 90% of chronic wounds have biofilm versus only 6% of acute wounds. While many studies confirm that chronic wounds often contain a polymicrobial flora, controversy remains with regard to whether these organisms directly contribute to non-healing. It seems most likely that individual bacteria themselves are not directly responsible for non-healing wounds. Rather, there is direct correlation between the presence of four or more distinct bacterial species in a wound and non-healing, suggesting that mixed microbial populations are the cause of pathology. The most reliable method to confirm the presence of a biofilm is specialized microscopy, e.g., bright-field, fluorescence in situ hybridization (FISH), and environmental scanning electron microscope (ESEM). Surface wound cultures underestimate total wound microbiota--misleading. Histological staining of deep debrided tissue shows evidence of biofilms. Now it is recognized that the majority of microbial species in chronic wounds are anaerobic bacteria (deep swabbing techniques yield similar findings to biopsies) if samples are processed within two hours. Traditional (wound culture method) cultures have limitations because all microbes (the organisms within the biofilm) cannot be isolated in culture or cannot be detected. Therefore, the most effective methods are molecular}, } @article {pmid27220186, year = {2016}, author = {Kulisić, SM and Lipozencić, J and Tunuković, S}, title = {[ANTIMICROBIAL DRESSINGS FOR INFECTED ULCER AND CLINICAL COMPREHENSION OF BIOFILM].}, journal = {Acta medica Croatica : casopis Hravatske akademije medicinskih znanosti}, volume = {70}, number = {1}, pages = {23-27}, pmid = {27220186}, issn = {1330-0164}, mesh = {*Anti-Infective Agents ; *Bandages ; *Biofilms ; Humans ; *Ulcer ; Wound Healing ; *Wound Infection ; }, abstract = {Current knowledge and proofs of biofilm, interactions between various bacterial species and overall virulence of microbes play a role in delayed healing of wound and development of infection. High quality description of clinical symptoms and current knowledge of microbes provide an excellent guideline for creating the strategy of wound treatment. Owing to better understanding of the role of biofilm in prolongation of healing time and facts about biofilm system and structure, scientists have developed the Ag+ technology. This technology has strong synergistic effects of the general and antimicrobial activity of ionic silver and specific compounds, which have proved efficient in biofilm obstruction and removal.}, } @article {pmid27219222, year = {2016}, author = {Adams, WP}, title = {Discussion: Bacterial Biofilm Infection Detected in Breast Implant-Associated Anaplastic Large-Cell Lymphoma.}, journal = {Plastic and reconstructive surgery}, volume = {137}, number = {6}, pages = {1670-1672}, doi = {10.1097/PRS.0000000000002170}, pmid = {27219222}, issn = {1529-4242}, mesh = {Biofilms ; Breast Implantation ; Breast Implants/*microbiology ; Breast Neoplasms ; Humans ; *Lymphoma, Large-Cell, Anaplastic ; }, } @article {pmid27217365, year = {2016}, author = {Kroning, IS and Iglesias, MA and Sehn, CP and Valente Gandra, TK and Mata, MM and da Silva, WP}, title = {Staphylococcus aureus isolated from handmade sweets: Biofilm formation, enterotoxigenicity and antimicrobial resistance.}, journal = {Food microbiology}, volume = {58}, number = {}, pages = {105-111}, doi = {10.1016/j.fm.2016.04.001}, pmid = {27217365}, issn = {1095-9998}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*growth & development ; Brazil ; Coagulase/genetics ; Drug Resistance, Bacterial ; Enterotoxins/genetics ; Humans ; Staphylococcus aureus/drug effects/genetics/isolation & purification/*physiology ; Virulence ; }, abstract = {Staphylococcus aureus is the second most important pathogen involved in foodborne outbreaks in Brazil. Because of their widespread distribution and biofilm forming ability, handmade sweets are easily contaminated with S. aureus. The aim of this study was to isolate and identify coagulase-positive staphylococci (CPS) from handmade sweets produced in Pelotas City/Brazil. The virulence potential was checked by evaluating the presence of the staphylococcal enterotoxin genes, icaA and icaD genes, the biofilm forming potential and antimicrobial resistance of the isolates. It was find just S. aureus among the CPS isolates. All the S. aureus isolates had biofilm forming ability on stainless steel and more than half of them on polystyrene surfaces. The majority of the isolates carried the icaA (66.6%) and icaD (58.4%) genes and some of them had the genes encoding enterotoxins A (33.4%) and B (16.6%). Furthermore, the majority of the isolates (83%) were resistant to at least one of the tested antimicrobials and multidrug resistance was observed in 8.4% of the isolates. The isolates had virulence potential, and half of them were enterotoxigenic. In addition, the ability of all the isolates to produce biofilms highlights the danger posed by these potentially virulent microorganisms persisting in food manufacturing environments.}, } @article {pmid27216052, year = {2016}, author = {Wang, YC and Kuo, SC and Yang, YS and Lee, YT and Chiu, CH and Chuang, MF and Lin, JC and Chang, FY and Chen, TL}, title = {Individual or Combined Effects of Meropenem, Imipenem, Sulbactam, Colistin, and Tigecycline on Biofilm-Embedded Acinetobacter baumannii and Biofilm Architecture.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {8}, pages = {4670-4676}, pmid = {27216052}, issn = {1098-6596}, mesh = {Acinetobacter Infections/drug therapy ; Acinetobacter baumannii/*drug effects ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Carbapenems/pharmacology ; Colistin/*pharmacology ; Drug Combinations ; Drug Resistance, Bacterial ; Drug Synergism ; Humans ; Imipenem/*pharmacology ; Meropenem ; Microbial Sensitivity Tests/methods ; Minocycline/*analogs & derivatives/pharmacology ; Sulbactam/*pharmacology ; Thienamycins/*pharmacology ; Tigecycline ; }, abstract = {Acinetobacter baumannii biofilms are difficult to eradicate. We investigated the effects of meropenem (2 mg/liter), imipenem (2 mg/liter), sulbactam (4 mg/liter), colistin (2 mg/liter), and tigecycline (2 mg/liter), alone or in combination, on biofilm-embedded carbapenem-resistant and carbapenem-susceptible A. baumannii (CRAb and CSAb, respectively) cells, as well as on the architecture of the biofilms. A. baumannii ATCC 15151 (Ab15151) and its OXA-82-overproducing transformant, along with two clinical CSAb and two clinical CRAb isolates of differing clonalities, were used. The minimal bactericidal concentrations for biofilm-embedded cells of the six tested isolates were >50-fold those of their planktonic cells. When used individually, meropenem exhibited a higher killing effect than the other four antimicrobials on biofilm-embedded CSAb cells in the colony biofilm assay. For two clinical CRAb isolates, meropenem plus sulbactam or sulbactam plus tigecycline showed >100-fold the bactericidal effect exhibited by these agents used alone after 48 h of treatment. The effect of antimicrobials on the architecture of Ab15151 biofilm emitting green fluorescence was determined by confocal laser scanning microscopy using COMSTAT software. Significant decreases in the maximum biofilm thickness were observed after exposure to meropenem and imipenem. Meropenem plus sulbactam significantly decreased the biomass and mean thickness and increased the roughness coefficient of biofilms, but sulbactam plus tigecycline only decreased the maximum and mean biofilm thickness compared to any of these agents used alone. Meropenem was active against biofilm-embedded CSAb, whereas meropenem plus sulbactam exhibited synergism against biofilm-embedded CRAb and caused significantly more damage to the biofilm architecture than did any of the agents used alone.}, } @article {pmid27215787, year = {2016}, author = {Siegel, SD and Wu, C and Ton-That, H}, title = {A Type I Signal Peptidase Is Required for Pilus Assembly in the Gram-Positive, Biofilm-Forming Bacterium Actinomyces oris.}, journal = {Journal of bacteriology}, volume = {198}, number = {15}, pages = {2064-2073}, pmid = {27215787}, issn = {1098-5530}, support = {R01 DE017382/DE/NIDCR NIH HHS/United States ; }, mesh = {Actinomyces/*enzymology/genetics/physiology ; Bacterial Proteins/genetics/*metabolism ; Biofilms ; Down-Regulation ; Fimbriae, Bacterial/*physiology ; Gene Expression Regulation, Bacterial/*physiology ; Gene Expression Regulation, Enzymologic/*physiology ; Membrane Proteins/genetics/*metabolism ; Serine Endopeptidases/genetics/*metabolism ; }, abstract = {UNLABELLED: The Gram-positive bacterium Actinomyces oris, a key colonizer in the development of oral biofilms, contains 18 LPXTG motif-containing proteins, including fimbrillins that constitute two fimbrial types critical for adherence, biofilm formation, and polymicrobial interactions. Export of these protein precursors, which harbor a signal peptide, is thought to be mediated by the Sec machine and require cleavage of the signal peptide by type I signal peptidases (SPases). Like many Gram-positive bacteria, A. oris expresses two SPases, named LepB1 and LepB2. The latter has been linked to suppression of lethal "glyco-stress," caused by membrane accumulation of the LPXTG motif-containing glycoprotein GspA when the housekeeping sortase srtA is genetically disrupted. Consistent with this finding, we show here that a mutant lacking lepB2 and srtA was unable to produce high levels of glycosylated GspA and hence was viable. However, deletion of neither lepB1 nor lepB2 abrogated the signal peptide cleavage and glycosylation of GspA, indicating redundancy of SPases for GspA. In contrast, the lepB2 deletion mutant failed to assemble the wild-type levels of type 1 and 2 fimbriae, which are built by the shaft fimbrillins FimP and FimA, respectively; this phenotype was attributed to aberrant cleavage of the fimbrillin signal peptides. Furthermore, the lepB2 mutants, including the catalytically inactive S101A and K169A variants, exhibited significant defects in polymicrobial interactions and biofilm formation. Conversely, lepB1 was dispensable for the aforementioned processes. These results support the idea that LepB2 is specifically utilized for processing of fimbrial proteins, thus providing an experimental model with which to study the basis of type I SPase specificity.

IMPORTANCE: Sec-mediated translocation of bacterial protein precursors across the cytoplasmic membrane involves cleavage of their signal peptide by a signal peptidase (SPase). Like many Gram-positive bacteria, A. oris expresses two SPases, LepB1 and LepB2. The latter is a genetic suppressor of lethal "glyco-stress" caused by membrane accumulation of glycosylated GspA when the housekeeping sortase srtA is genetically disrupted. We show here that LepB1 and LepB2 are capable of processing GspA, whereas only LepB2 is required for cleavage of fimbrial signal peptides. This is the first example of a type I SPase dedicated to LPXTG motif-containing fimbrial proteins. Thus, A. oris provides an experimental model with which to investigate the specificity mechanism of type I SPases.}, } @article {pmid27215719, year = {2016}, author = {Bardes, JM and Waters, C and Motlagh, H and Wilson, A}, title = {The Prevalence of Oral Flora in the Biofilm Microbiota of the Endotracheal Tube.}, journal = {The American surgeon}, volume = {82}, number = {5}, pages = {403-406}, pmid = {27215719}, issn = {1555-9823}, mesh = {Adult ; Aged ; Aged, 80 and over ; Biofilms ; Critical Care/methods ; Equipment Contamination/prevention & control/*statistics & numerical data ; Female ; Hospitals, University ; Humans ; Intensive Care Units ; Intubation, Intratracheal/*instrumentation/methods ; Male ; Microbiota ; Middle Aged ; Mouth Mucosa/*microbiology ; Pneumonia, Ventilator-Associated/epidemiology/*microbiology ; Prevalence ; Prospective Studies ; Sensitivity and Specificity ; Trauma Centers ; Young Adult ; }, abstract = {The endotracheal tube (ETT) is recognized as an independent factor for infection in intubated patients. The presence of biofilm contributes to the development of pneumonia. Standard culturing techniques are inadequate to detect many of the bacteria present in a biofilm. Delineation of the microbiota in the ETT is needed to further understand infections in ventilated patients. A prospective, observational study was performed at a university, Level I trauma center. Twenty ETT were collected at extubation. Bioluminal accretions were removed and quantified. DNA was extracted and 16S ribosomal RNA gene analysis performed using the Human Oral Microbe Identification Microarray. Twenty ETT were evaluated. Mean age was 47.5 years (19-82). Five were smokers. Mean ventilator days was 3.6 ± 3.1. Mean intensive care unit days was 7.8 ± 6.3. In those ETT, 87 different bacterial species were identified. Mean number of bacterial species identified was 16 ± 9 (3-35). There was no relationship between duration of intubation and number of species (P = 0.5). Nonsmokers had a greater variety of bacteria than smokers (P = 0.03). Patients with pneumonia did not have a greater variety of bacteria (P = 0.14). Parvimonas micra presence was associated with reintubation (P = 0.01). The most common species in smokers were different from nonsmokers. There is a wide variety of bacteria present in an ETT, many of which cannot be cultured by standard means. Variation is not correlated to duration of intubation or accretion volume. Studies to evaluate these bacteria and their interaction with the biofilm may further delineate factors in development of infections.}, } @article {pmid27214405, year = {2016}, author = {Aamdal Scheie, A and Chamgordani, EJ and Naemi, AO and Hansen, FK and Benneche, T}, title = {Staphylococcus epidermidis biofilm on implant material is reduced by a covalently linked thiophenone.}, journal = {Journal of applied microbiology}, volume = {121}, number = {2}, pages = {547-553}, doi = {10.1111/jam.13188}, pmid = {27214405}, issn = {1365-2672}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biocompatible Materials/*chemistry ; Biofilms/*drug effects ; Humans ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/microbiology/*prevention & control ; Quorum Sensing/drug effects ; Stainless Steel ; Staphylococcal Infections/microbiology/*prevention & control ; Staphylococcus epidermidis/*drug effects/physiology ; Thiophenes/*pharmacology ; }, abstract = {AIMS: The present aims were firstly to coat metal implant material with a quorum sensing inhibitory thiophenone molecule, and secondly to assess the inhibitory effect on Staphylococcus epidermidis biofilm accumulation on thiophenone-coated coupons.

METHOD AND RESULTS: Thiophenone- and control-coated metal coupons were prepared by silane hydrolysis and dip coating. The linking of thiophenone to the surface was confirmed by X-ray photoelectron spectroscopy analyses. Biofilm by Staph. epidermidis, a frequent cause of implant-associated infections, was allowed to form under flowing conditions for 48 h. The biofilm accumulations were significantly reduced on the thiophenone-coated coupons. This was confirmed by confocal scanning microscopy.

CONCLUSION: This study showed for the first time how a synthetic thiophenone may be covalently linked to a stainless steel surface, and that biofilm accumulations on such surfaces are significantly reduced.

Functionalizing surfaces by covalent linking of thiophenones might open a wide array of applications. Thiophenone coating of medical implants represents a novel and promising approach to prevent implant-associated infections.}, } @article {pmid27214346, year = {2016}, author = {Reid, T and VanMensel, D and Droppo, IG and Weisener, CG}, title = {The symbiotic relationship of sediment and biofilm dynamics at the sediment water interface of oil sands industrial tailings ponds.}, journal = {Water research}, volume = {100}, number = {}, pages = {337-347}, doi = {10.1016/j.watres.2016.05.025}, pmid = {27214346}, issn = {1879-2448}, mesh = {Biofilms ; *Oil and Gas Fields ; *Ponds ; Water ; Water Pollutants, Chemical ; }, abstract = {Within the oil sands industry, tailings ponds are used as a means of retaining tailings until a reclamation technology such as end pit lakes (EPLs) can be developed and optimized to remediate such tailings with a water cap (although dry-land strategies for tailing reclamation are also being developed). EPLs have proven successful for other mining ventures (e.g. metal rock mines) in eventually mitigating contaminant loads to receiving waters once biochemical remediation has taken place (although the duration for this to occur may be decades). While the biological interactions at the sediment water interface of tailings ponds or EPLs have been shown to control biogeochemical processes (i.e. chemical fluxes and redox profiles), these have often been limited to static microcosm conditions. Results from such experiments may not tell the whole story given that the sediment water interface often represents a dynamic environment where erosion and deposition may be occurring in association with microbial growth and decay. Mobilization of sediments and associated contaminants may therefore have a profound effect on remediation rates and, as such, may decrease the effectiveness of EPLs as viable reclamation strategies for mining industries. Using a novel core erosion system (U-GEMS), this paper examines how the microbial community can influence sediment water interface stability and how the biofilm community may change with tailings age and after disturbance (biofilm reestablishment). Shear strength, eroded mass measurements, density gradients, high-resolution microscopy, and microbial community analyses were made on 2 different aged tailings (fresh and ∼38 years) under biotic and abiotic conditions. The same experiments were repeated as duplicates with both sets of experiments having consolidation/biostabilization periods of 21 days. Results suggest that the stability of the tailings varies between types and conditions with the fresh biotic tailings experiencing up to 75% more biostabilization than the same abiotic tailings. Further, greater microbial diversity in the aged pond could be a contributing factor to the overall increase in stability of this material over the fresh tailings source.}, } @article {pmid27214174, year = {2016}, author = {Dalecki, AG and Crawford, CL and Wolschendorf, F}, title = {Targeting Biofilm Associated Staphylococcus aureus Using Resazurin Based Drug-susceptibility Assay.}, journal = {Journal of visualized experiments : JoVE}, volume = {}, number = {111}, pages = {}, pmid = {27214174}, issn = {1940-087X}, support = {P30 AI027767/AI/NIAID NIH HHS/United States ; R01 AI104952/AI/NIAID NIH HHS/United States ; }, mesh = {*Biofilms/drug effects ; *Biological Assay ; Oxazines ; Reproducibility of Results ; Staphylococcal Infections/microbiology/therapy ; *Staphylococcus aureus ; Xanthenes ; }, abstract = {Most pathogenic bacteria are able to form biofilms during infection, but due to the difficulty of manipulating and assessing biofilms, the vast majority of laboratory work is conducted with planktonic cells. Here, we describe a peg plate biofilm assay as performed with Staphylococcus aureus. Bacterial biofilms are grown on pegs attached to a 96-well microtiter plate lid, washed through gentle submersion in buffer, and placed in a drug challenge plate. After subsequent incubation they are again washed and moved to a final recovery plate, in which the fluorescent dye resazurin serves as a viability indicator. This assay offers greatly increased ease-of-use, reliability, and reproducibility, as well as a wealth of data when conducted as a kinetic read. Moreover, this assay can be adapted to a medium-throughput drug screening approach by which an endpoint fluorescent readout is taken instead, offering a path for drug discovery efforts.}, } @article {pmid27209601, year = {2016}, author = {Vyshnava, SS and Kanderi, DK and Panjala, SP and Pandian, K and Bontha, RR and Goukanapalle, PK and Banaganapalli, B}, title = {Effect of Silver Nanoparticles Against the Formation of Biofilm by Pseudomonas aeruginosa an In silico Approach.}, journal = {Applied biochemistry and biotechnology}, volume = {180}, number = {3}, pages = {426-437}, doi = {10.1007/s12010-016-2107-7}, pmid = {27209601}, issn = {1559-0291}, mesh = {Bacterial Proteins/chemistry ; Biofilms/*drug effects ; *Computer Simulation ; Ligands ; Metal Nanoparticles/*chemistry ; Models, Molecular ; Pseudomonas aeruginosa/drug effects/*physiology ; Reproducibility of Results ; Silver/*pharmacology ; }, abstract = {Studies were undertaken to examine the mechanism of mediation of silver nanoparticles in inhibiting biofilm formation by Pseudomonas aeruginosa through LuxI/LuxR system of signal transduction. This study includes the basic signaling transduction mechanism LasR, QscR, RhlR, and Vfr signaling model systems. The arbitrary homology models built with the I-TASSER server were evaluated and validated with the Qmean web server. Based on the Z-score and the relative square mean distance (RMSD) values, the structures were validated. The interaction results of the nanoparticle with the rigid docking proved the requirement of minimal energy for the inhibition of the protein active site by the silver nanoparticle. This principle docking experiment suggests that the biofilm formation in Gram-negative bacteria can be inhibited by the silver nanoparticles at the signal transduction level. Graphical abstract Systematic outline of present study; Stage one provides the data sampling and generation of pdb systems to conform the structure of bacterial signal sytems like LasR/LasI; RhlR/RhrI; QscR/QscI; VfrR/VfrI. Stage two involves docking of silver nanoparticles with Bacterial signal protein strucutres which are listed in Stage one. The Final Stage involves in understanding the development of appropriate mechanism behind the biofilm inhibition by silver nanoparticles.}, } @article {pmid27209234, year = {2016}, author = {de Melo Souza, PL and Arruda, EL and Pazini, F and Menegatti, R and Vaz, BG and Lião, LM and de Oliveira, V}, title = {One step N-glycosylation by filamentous fungi biofilm in bioreactor of a new phosphodiesterase-3 inhibitor tetrazole.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {26}, number = {13}, pages = {3177-3181}, doi = {10.1016/j.bmcl.2016.04.085}, pmid = {27209234}, issn = {1464-3405}, mesh = {*Biofilms ; *Bioreactors ; Cunninghamella/*metabolism ; Dose-Response Relationship, Drug ; Glycosylation ; Molecular Structure ; Phosphodiesterase 3 Inhibitors/chemistry/metabolism/*pharmacology ; Phosphoric Diester Hydrolases/*metabolism ; Structure-Activity Relationship ; Tetrazoles/chemistry/metabolism/*pharmacology ; }, abstract = {An efficient and rapid process for N-glycosylation of 5-(1-(3-fluorophenyl)-1H-pyrazol-4-yl)-2H-tetrazole-LQFM 021 (1), a new synthetic derivative of pyrazole with phosphodiesterase-3 (PDE-3) inhibitory action, vasorelaxant activity and low toxicity catalyzed by filamentous fungi biofilm in bioreactor was successfully developed. A maximum N-glycosyl yield of 68% was obtained with Cunninghamella echinulata ATCC 9244 biofilm in bioreactor with conditions of 25mgml(-1) of 1 in PDSM medium at 28°C for 96h. After extraction with ethyl acetate, the derivative was identified by Ultrahigh Resolution Mass Spectrometry and (1)H-(13)C HSQC/HMBC.}, } @article {pmid27208119, year = {2016}, author = {Douterelo, I and Husband, S and Loza, V and Boxall, J}, title = {Dynamics of Biofilm Regrowth in Drinking Water Distribution Systems.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {14}, pages = {4155-4168}, pmid = {27208119}, issn = {1098-5336}, mesh = {Bacteria/classification/genetics/isolation & purification ; Bacterial Physiological Phenomena/*drug effects ; Biofilms/*growth & development ; Cluster Analysis ; DNA, Ribosomal/chemistry/genetics ; Drinking Water/*microbiology ; Halogenation ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; United Kingdom ; Water Purification ; Water Supply ; }, abstract = {UNLABELLED: The majority of biomass within water distribution systems is in the form of attached biofilm. This is known to be central to drinking water quality degradation following treatment, yet little understanding of the dynamics of these highly heterogeneous communities exists. This paper presents original information on such dynamics, with findings demonstrating patterns of material accumulation, seasonality, and influential factors. Rigorous flushing operations repeated over a 1-year period on an operational chlorinated system in the United Kingdom are presented here. Intensive monitoring and sampling were undertaken, including time-series turbidity and detailed microbial analysis using 16S rRNA Illumina MiSeq sequencing. The results show that bacterial dynamics were influenced by differences in the supplied water and by the material remaining attached to the pipe wall following flushing. Turbidity, metals, and phosphate were the main factors correlated with the distribution of bacteria in the samples. Coupled with the lack of inhibition of biofilm development due to residual chlorine, this suggests that limiting inorganic nutrients, rather than organic carbon, might be a viable component in treatment strategies to manage biofilms. The research also showed that repeat flushing exerted beneficial selective pressure, giving another reason for flushing being a viable advantageous biofilm management option. This work advances our understanding of microbiological processes in drinking water distribution systems and helps inform strategies to optimize asset performance.

IMPORTANCE: This research provides novel information regarding the dynamics of biofilm formation in real drinking water distribution systems made of different materials. This new knowledge on microbiological process in water supply systems can be used to optimize the performance of the distribution network and to guarantee safe and good-quality drinking water to consumers.}, } @article {pmid27208110, year = {2016}, author = {Townsley, L and Sison Mangus, MP and Mehic, S and Yildiz, FH}, title = {Response of Vibrio cholerae to Low-Temperature Shifts: CspV Regulation of Type VI Secretion, Biofilm Formation, and Association with Zooplankton.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {14}, pages = {4441-4452}, pmid = {27208110}, issn = {1098-5336}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R56 AI102584/AI/NIAID NIH HHS/United States ; S10 RR020939/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Bacterial Adhesion ; Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; *Cold Temperature ; Daphnia/microbiology ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Heat-Shock Proteins/*metabolism ; Stress, Physiological ; Survival Analysis ; Type VI Secretion Systems/*metabolism ; Vibrio cholerae/physiology/*radiation effects ; Virulence ; Zooplankton/*growth & development ; }, abstract = {UNLABELLED: The ability to sense and adapt to temperature fluctuation is critical to the aquatic survival, transmission, and infectivity of Vibrio cholerae, the causative agent of the disease cholera. Little information is available on the physiological changes that occur when V. cholerae experiences temperature shifts. The genome-wide transcriptional profile of V. cholerae upon a shift in human body temperature (37°C) to lower temperatures, 15°C and 25°C, which mimic those found in the aquatic environment, was determined. Differentially expressed genes included those involved in the cold shock response, biofilm formation, type VI secretion, and virulence. Analysis of a mutant lacking the cold shock gene cspV, which was upregulated >50-fold upon a low-temperature shift, revealed that it regulates genes involved in biofilm formation and type VI secretion. CspV controls biofilm formation through modulation of the second messenger cyclic diguanylate and regulates type VI-mediated interspecies killing in a temperature-dependent manner. Furthermore, a strain lacking cspV had significant defects for attachment and type VI-mediated killing on the surface of the aquatic crustacean Daphnia magna Collectively, these studies reveal that cspV is a major regulator of the temperature downshift response and plays an important role in controlling cellular processes crucial to the infectious cycle of V. cholerae

IMPORTANCE: Little is known about how human pathogens respond and adapt to ever-changing parameters of natural habitats outside the human host and how environmental adaptation alters dissemination. Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, experiences fluctuations in temperature in its natural aquatic habitats and during the infection process. Furthermore, temperature is a critical environmental signal governing the occurrence of V. cholerae and cholera outbreaks. In this study, we showed that V. cholerae reprograms its transcriptome in response to fluctuations in temperature, which results in changes to biofilm formation and type VI secretion system activation. These processes in turn impact environmental survival and the virulence potential of this pathogen.}, } @article {pmid27208104, year = {2016}, author = {Wu, Y and Mohanty, A and Chia, WS and Cao, B}, title = {Influence of 3-Chloroaniline on the Biofilm Lifestyle of Comamonas testosteroni and Its Implications on Bioaugmentation.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {14}, pages = {4401-4409}, pmid = {27208104}, issn = {1098-5336}, mesh = {Aniline Compounds/*metabolism/toxicity ; Biofilms/*drug effects/*growth & development ; Comamonas testosteroni/*drug effects/genetics/*physiology ; Cyclic GMP/analogs & derivatives/metabolism ; Gene Expression Profiling ; Water Pollutants/*metabolism/toxicity ; }, abstract = {UNLABELLED: Bioaugmentation has been frequently proposed in wastewater and soil treatment to remove toxic aromatic compounds. The performance of bioaugmentation is affected by a number of biological and environmental factors, including the interaction between the target pollutant and the augmented bacterial cells. In this study, using Comamonas testosteroni and 3-chloroaniline (3-CA) as the model organism and target pollutant, we explored the influence of toxic aromatic pollutants on the biofilm lifestyle of bacteria capable of degrading aromatic compounds toward a better understanding of cell-pollutant interaction in bioaugmentation. Our results showed that the exposure to 3-CA greatly reduced the retention of C. testosteroni cells in packed-bed bioreactors (from 22% to 15% after three pore volumes), which could be attributed to the altered bacterial motility and cell surface hydrophobicity. To further understand the molecular mechanisms, we employed an integrated genomic and transcriptomic analysis to examine the influence of 3-CA on the expression of genes important to the biofilm lifestyle of C. testosteroni We found that exposure to 3-CA reduced the intracellular c-di-GMP level by downregulating the expression of genes encoding c-di-GMP synthases and induced massive cell dispersal from the biofilms. Our findings provide novel environmental implications on bioaugmentation, particularly in biofilm reactors, for the treatment of wastewater containing recalcitrant industrial pollutants.

IMPORTANCE: Bioaugmentation is a bioremediation approach that often has been described in the literature but has almost never been successfully applied in practice. Many biological and environmental factors influence the overall performance of bioaugmentation. Among these, the interaction between the target pollutant and the augmented bacterial cells is one of the most important factors. In this study, we revealed the influence of toxic aromatic pollutants on the biofilm lifestyle of bacteria capable of degrading aromatic compounds toward a better understanding of cell-pollutant interaction in bioaugmentation. Our findings provide novel environmental implications on bioaugmentation for the treatment of wastewater containing recalcitrant industrial pollutants; in particular, the exposure to toxic pollutants may reduce the retention of augmented organisms in biofilm reactors by reducing the c-di-GMP level, and approaches to elevating or maintaining a high c-di-GMP level may be promising to establish and maintain sustainable bioaugmentation activity.}, } @article {pmid27207196, year = {2016}, author = {Panhóca, VH and Florez, F and Batista de Faria, N and Rastelli, AN and Tanomaru, J and Kurachi, C and Bagnato, VS}, title = {Evaluation of Antimicrobial Photodynamic Therapy against Streptococcus mutans Biofilm in situ.}, journal = {The journal of contemporary dental practice}, volume = {17}, number = {3}, pages = {184-191}, doi = {10.5005/jp-journals-10024-1825}, pmid = {27207196}, issn = {1526-3711}, mesh = {Adolescent ; Biofilms/*drug effects/*radiation effects ; Curcumin/therapeutic use ; Female ; Hematoporphyrins/therapeutic use ; Humans ; Male ; *Photochemotherapy ; Photosensitizing Agents/therapeutic use ; Streptococcus mutans/isolation & purification ; }, abstract = {AIM: This study investigated the effect of antimicrobial photo-dynamic therapy (aPDT) over Streptococcus mutans biofilm.

MATERIALS AND METHODS: Eighteen (n = 18) patients were selected and one palatine device with dental blocks was used. The biofilm was treated by curcumin and Photogem® with a LED and the effect was analyzed by CFU/ml.

RESULTS: Although, statistical analysis showed significant reductions for aPDT mainly with Photogem® (p = 0.02), these were low.

CONCLUSION: The results suggest a low antimicrobial effect of aPDT over S. mutans biofilm. Some parameters used need to be improved.

CLINICAL SIGNIFICANCE: This technique can be a promising in Dentistry.}, } @article {pmid27207160, year = {2016}, author = {Selek, MB and Kula Atik, T and Bektöre, B and Atik, B and Demir, S and Baylan, O and Özyurt, M}, title = {First report of macroscopic biofilm formation caused by Candida albicans on silver hydrogel-coated urinary catheters.}, journal = {American journal of infection control}, volume = {44}, number = {10}, pages = {1174-1175}, doi = {10.1016/j.ajic.2016.03.042}, pmid = {27207160}, issn = {1527-3296}, mesh = {Biofilms/*growth & development ; Candida albicans/*drug effects/growth & development/isolation & purification ; Humans ; Hydrogel, Polyethylene Glycol Dimethacrylate/*pharmacology ; Intensive Care Units ; Silver/pharmacology ; Urinary Catheters/*microbiology ; Urinary Tract Infections/*prevention & control ; }, abstract = {We report macroscopic biofilms on silver hydrogel-coated urinary catheters in 2 patients from 2 different intensive care units. The catheters were removed on observation of a white, jelly layer on the catheters, respectively, 9 and 21 days after insertion. Yeast cells and pseudohyphal structures were observed with microscopy. Both isolates were identified as Candida albicans. To our knowledge, these are the first cases demonstrating the formation of macroscopic biofilm layers on silver nitrate-coated catheters in the literature.}, } @article {pmid27207065, year = {2016}, author = {Wu, BS and Gopal, J and Hua, PY and Wu, HF}, title = {Graphene nanosheet mediated MALDI-MS (GN-MALDI-MS) for rapid, in situ detection of intact incipient biofilm on material surfaces.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {66}, number = {}, pages = {285-296}, doi = {10.1016/j.msec.2016.04.053}, pmid = {27207065}, issn = {1873-0191}, mesh = {Aluminum/chemistry ; *Biofilms/growth & development ; Graphite/*chemistry ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Nanostructures/*chemistry ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Staphylococcus aureus/physiology ; Titanium/chemistry ; Vibrio alginolyticus/physiology ; }, abstract = {Detection is the first step to efficient treatment, therefore early detection of biofilm gains paramount importance for the initiation of mitigation protocols. A systematic study was conducted to detect the biofilm formation (1h to 2month period) on aluminium, titanium surfaces and their corresponding oxide film surfaces. The limit of detection (LOD) in case of traditional MALDI-MS was limited to a 6h old biofilm. Whereas, in case of the Graphene nanosheet mediated MALDI-MS (GN-MALDI-MS) approach, early detection of the biofilm was demonstrated to be 1h on titanium surfaces and 3h for Al surfaces.}, } @article {pmid27206613, year = {2016}, author = {Parker, RE and Laut, C and Gaddy, JA and Zadoks, RN and Davies, HD and Manning, SD}, title = {Association between genotypic diversity and biofilm production in group B Streptococcus.}, journal = {BMC microbiology}, volume = {16}, number = {}, pages = {86}, pmid = {27206613}, issn = {1471-2180}, mesh = {Animals ; Bacterial Proteins/genetics ; *Biofilms ; Cattle ; Fimbriae, Bacterial/genetics ; Genetic Variation ; Genotype ; Humans ; Multilocus Sequence Typing/*methods ; Phylogeny ; Streptococcus agalactiae/*classification/isolation & purification/*physiology ; Virulence Factors/genetics ; }, abstract = {BACKGROUND: Group B Streptococcus (GBS) is a leading cause of sepsis and meningitis and an important factor in premature and stillbirths. Biofilm production has been suggested to be important for GBS pathogenesis alongside many other elements, including phylogenetic lineage and virulence factors, such as pili and capsule type. A complete understanding of the confluence of these components, however, is lacking. To identify associations between biofilm phenotype, pilus profile and lineage, 293 strains from asymptomatic carriers, invasive disease cases, and bovine mastitis cases, were assessed for biofilm production using an in vitro assay.

RESULTS: Multilocus sequence type (ST) profile, pilus island profile, and isolate source were associated with biofilm production. Strains from invasive disease cases and/or belonging to the ST-17 and ST-19 lineages were significantly more likely to form weak biofilms, whereas strains producing strong biofilms were recovered more frequently from individuals with asymptomatic colonization.

CONCLUSIONS: These data suggest that biofilm production is a lineage-specific trait in GBS and may promote colonization of strains representing lineages other than STs 17 and 19. The findings herein also demonstrate that biofilms must be considered in the treatment of pregnant women, particularly for women with heavy GBS colonization.}, } @article {pmid27199942, year = {2016}, author = {Bastard, A and Coelho, C and Briandet, R and Canette, A and Gougeon, R and Alexandre, H and Guzzo, J and Weidmann, S}, title = {Effect of Biofilm Formation by Oenococcus oeni on Malolactic Fermentation and the Release of Aromatic Compounds in Wine.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {613}, pmid = {27199942}, issn = {1664-302X}, abstract = {The winemaking process involves the alcoholic fermentation of must, often followed by malolactic fermentation (MLF). The latter, mainly carried out by the lactic acid bacterium Oenococcus oeni, is used to improve wine quality when acidity reduction is required. Moreover, it prevents microbial spoilage and improves the wine's organoleptic profile. Prior observations showed that O. oeni is able to resist several months in harsh wine conditions when adhered on oak barrels. Since biofilm is a prevailing microbial lifestyle in natural environments, the capacity of O. oeni to form biofilms was investigated on winemaking material such as stainless steel and oak chips. Scanning Electron Microscopy and Confocal Laser Scanning Microscopy showed that O. oeni was able to adhere to these surfaces and form spatially organized microcolonies embedded in extracellular substances. To assess the competitive advantage of this mode of life in wine, the properties of biofilm and planktonic cells were compared after inoculation in a fermented must (pH 3.5 or 3.2 and 12% ethanol) The results indicated that the biofilm culture of O. oeni conferred (i) increased tolerance to wine stress, and (ii) functional performance with effective malolactic activities. Relative gene expression focusing on stress genes and genes involved in EPS synthesis was investigated in a mature biofilm and emphasized the role of the matrix in increased biofilm resistance. As oak is commonly used in wine aging, we focused on the O. oeni biofilm on this material and its contribution to the development of wine color and the release of aromatic compounds. Analytical chromatography was used to target the main oak aging compounds such as vanillin, gaiacol, eugenol, whisky-lactones, and furfural. The results reveal that O. oeni biofilm developed on oak can modulate the wood-wine transfer of volatile aromatic compounds during MLF and aging by decreasing furfural, gaiacol, and eugenol in particular. This work showed that O. oeni forms biofilms consisting of stress-tolerant cells capable of efficient MLF under winemaking conditions. Therefore surface-associated behaviors should be considered in the development of improved strategies for the control of MLF in wine.}, } @article {pmid27199927, year = {2016}, author = {Qi, Z and Chen, L and Zhang, W}, title = {Comparison of Transcriptional Heterogeneity of Eight Genes between Batch Desulfovibrio vulgaris Biofilm and Planktonic Culture at a Single-Cell Level.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {597}, pmid = {27199927}, issn = {1664-302X}, abstract = {Sulfate-reducing bacteria (SRB) biofilm formed on metal surfaces can change the physicochemical properties of metals and cause metal corrosion. To enhance understanding of differential gene expression in Desulfovibrio vulgaris under planktonic and biofilm growth modes, a single-cell based RT-qPCR approach was applied to determine gene expression levels of 8 selected target genes in four sets of the 31 individual cells isolated from each growth condition (i.e., biofilm formed on a mild steel (SS) and planktonic cultures, exponential and stationary phases). The results showed obvious gene-expression heterogeneity for the target genes among D. vulgaris single cells of both biofilm and planktonic cultures. In addition, an increased gene-expression heterogeneity in the D. vulgaris biofilm when compared with the planktonic culture was also observed for seven out of eight selected genes at exponential phase, and six out of eight selected genes at stationary phase, respectively, which may be contributing to the increased complexity in terms of structures and morphology in the biofilm. Moreover, the results showed up-regulation of DVU0281 gene encoding exopolysaccharide biosynthesis protein, and down-regulation of genes involved in energy metabolism (i.e., DVU0434 and DVU0588), stress responses (i.e., DVU2410) and response regulator (i.e., DVU3062) in the D. vulgaris biofilm cells. Finally, the gene (DVU2571) involved in iron transportation was found down-regulated, and two genes (DVU1340 and DVU1397) involved in ferric uptake repressor and iron storage were up-regulated in D. vulgaris biofilm, suggesting their possible roles in maintaining normal metabolism of the D. vulgaris biofilm under environments of high concentration of iron. This study showed that the single-cell based analysis could be a useful approach in deciphering metabolism of microbial biofilms.}, } @article {pmid27199924, year = {2016}, author = {Miquel, S and Lagrafeuille, R and Souweine, B and Forestier, C}, title = {Anti-biofilm Activity as a Health Issue.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {592}, pmid = {27199924}, issn = {1664-302X}, abstract = {The formation and persistence of surface-attached microbial communities, known as biofilms, are responsible for 75% of human microbial infections (National Institutes of Health). Biofilm lifestyle confers several advantages to the pathogens, notably during the colonization process of medical devices and/or patients' organs. In addition, sessile bacteria have a high tolerance to exogenous stress including anti-infectious agents. Biofilms are highly competitive communities and some microorganisms exhibit anti-biofilm capacities such as bacterial growth inhibition, exclusion or competition, which enable them to acquire advantages and become dominant. The deciphering and control of anti-biofilm properties represent future challenges in human infection control. The aim of this review is to compare and discuss the mechanisms of natural bacterial anti-biofilm strategies/mechanisms recently identified in pathogenic, commensal and probiotic bacteria and the main synthetic strategies used in clinical practice, particularly for catheter-related infections.}, } @article {pmid27196636, year = {2016}, author = {Van Kerckhoven, M and Hotterbeekx, A and Lanckacker, E and Moons, P and Lammens, C and Kerstens, M and Ieven, M and Delputte, P and Jorens, PG and Malhotra-Kumar, S and Goossens, H and Maes, L and Cos, P}, title = {Characterizing the in vitro biofilm phenotype of Staphylococcus epidermidis isolates from central venous catheters.}, journal = {Journal of microbiological methods}, volume = {127}, number = {}, pages = {95-101}, doi = {10.1016/j.mimet.2016.05.009}, pmid = {27196636}, issn = {1872-8359}, mesh = {*Biofilms ; Central Venous Catheters/*microbiology ; Humans ; Phenotype ; Staphylococcus epidermidis/*isolation & purification/*physiology ; }, abstract = {Central venous catheter (CVC)-related infections are commonly caused by Staphylococcus epidermidis that is able to form a biofilm on the catheter surface. Many studies involving biofilm formation by Staphylococcus have been published each adopting an own in vitro model. Since the capacity to form a biofilm depends on multiple environmental factors, direct comparison of results obtained in different studies remains challenging. This study characterized the phenotype (strong versus weak biofilm-producers) of S. epidermidis from CVCs in four different in vitro biofilm models, covering differences in material type (glass versus polymer) and nutrient presentation (static versus continuous flow). A good correlation in phenotype was obtained between glass and polymeric surfaces independent of nutrient flow, with 85% correspondence under static growth conditions and 80% under dynamic conditions. A 80% correspondence between static and dynamic conditions on polymeric surfaces could be demonstrated as well. Incubation time had a significant influence on the biofilm phenotype with only 55% correspondence between the dynamic models at different incubation times (48h versus 17h). Screening for the presence of biofilm-related genes only revealed that ica A was correlated with biofilm formation under static but not under dynamic conditions. In conclusion, this study highlights that a high level of standardization is necessary to interpret and compare results of different in vitro biofilm models.}, } @article {pmid27196401, year = {2017}, author = {Li, H and Lin, H and Xu, X and Jiang, M and Chang, CC and Xia, S}, title = {Simultaneous Bioreduction of Multiple Oxidized Contaminants Using a Membrane Biofilm Reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {89}, number = {2}, pages = {178-185}, doi = {10.2175/106143016X14609975746686}, pmid = {27196401}, issn = {1061-4303}, mesh = {Biodegradation, Environmental ; *Biofilms ; *Bioreactors ; Groundwater/*analysis ; Membranes, Artificial ; Oxidation-Reduction ; Water Pollutants, Chemical/*metabolism ; Water Purification/*methods ; }, abstract = {This study tests a hydrogen-based membrane biofilm reactor (MBfR) to investigate simultaneous bioreduction of selected oxidized contaminants, including nitrate (-N), sulfate (), bromate (), chromate (Cr(VI)) and para-chloronitrobenzene (p-CNB). The experiments demonstrate that MBfR can achieve high performance for contaminants bioreduction to harmless or immobile forms in 240 days, with a maximum reduction fluxes of 0.901 g -N/m2·d, 1.573 g /m2·d, 0.009 g /m2·d, 0.022 g Cr(VI)/m2·d, and 0.043 g p-CNB/m2·d. Increasing H2 pressure and decreasing influent surface loading enhanced removal efficiency of the reactor. Flux analysis indicates that nitrate and sulfate reductions competed more strongly than , Cr(VI) and p-CNB reduction. The average H2 utilization rate, H2 flux, and H2 utilization efficiency of the reactor were 0.026 to 0.052 mg H2/cm3·d, 0.024 to 0.046 mg H2/cm2·d, and 97.5% to 99.3% (nearly 100%). Results show the hydrogen-based MBfR may be suitable for removing multiple oxidized contaminants in drinking water or groundwater.}, } @article {pmid27193939, year = {2017}, author = {Gartenmann, SJ and Thurnheer, T and Attin, T and Schmidlin, PR}, title = {Influence of ultrasonic tip distance and orientation on biofilm removal.}, journal = {Clinical oral investigations}, volume = {21}, number = {4}, pages = {1029-1036}, pmid = {27193939}, issn = {1436-3771}, mesh = {*Biofilms ; Dental Plaque/*microbiology/*therapy ; Dental Scaling/*instrumentation ; Durapatite ; In Vitro Techniques ; Microscopy, Confocal ; Ultrasonic Therapy/*instrumentation ; }, abstract = {OBJECTIVE: The aim of this study is to assess the effects of ultrasonic tip distance and orientation on the removal of a multispecies biofilm under standardized conditions in vitro.

METHODS: Six-species biofilms were grown on hydroxyapatite discs for 64 h and treated with a magnetostrictive ultrasonic tip (Cavitron) placed either on contact or at 0.25- and 0.5-mm distance. The treatment was performed for 15 s with either the tip at right angle or sideways. Biofilm removal was evaluated by assessing the viable bacteria in each supernatant and compared to respective controls. In the latter, biofilms were mechanically removed and evaluated in supernatants to assess adhering and floating bacteria. Colony-forming units (CFU) were determined by cultivation on solid media. Any remaining biofilm on the treated discs was also visualized after staining with green-fluorescent SYTO® 9 stain using a confocal laser scanning microscope (CLSM). Mann-Whitney U tests and Bonferroni correction were used to analyze the results between the groups.

RESULTS: Sideways application of the ultrasonic tip at distances of 0.25 and 0.5 mm removed as many bacteria as present on the control discs compared to the tip on contact (p < 0.05). All other application modes, especially the ultrasonic tip applied perpendicularly on contact, showed no statistical significance in removing biofilm.

CONCLUSION: Overall, data indicated that bacterial detachment depended on tip orientation and distance, especially when the tip was applied sideways similar to the clinical setting.

CLINICAL RELEVANCE: Biofilm removal by means of ultrasonic debridement remains a crucial aspect in the treatment of periodontal disease. To ensure sufficient biofilm removal, the tip does not necessarily require contact to the surface, but an application parallel to the surface on the side is recommended.}, } @article {pmid27191568, year = {2016}, author = {Rava, E and Chirwa, E}, title = {Effect of carrier fill ratio on biofilm properties and performance of a hybrid fixed-film bioreactor treating coal gasification wastewater for the removal of COD, phenols and ammonia-nitrogen.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {10}, pages = {2461-2467}, doi = {10.2166/wst.2016.108}, pmid = {27191568}, issn = {0273-1223}, mesh = {Ammonia/metabolism ; Autotrophic Processes ; Bacteria/*growth & development ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Coal ; Heterotrophic Processes ; Industrial Waste ; Nitrification ; Nitrogen/chemistry/*metabolism ; Phenols/metabolism ; Waste Disposal, Fluid/methods ; Wastewater/*chemistry ; }, abstract = {The purpose of this study was to determine the effect different biofilm carrier filling ratios would have on biofilm morphology and activity and bacterial diversity in a hybrid fixed-film bioreactor treating high strength coal gasification wastewater (CGWW) for the removal of chemical oxygen demand (COD), phenols and ammonia-nitrogen. Results showed that a carrier fill of 70% formed a 'compact' biofilm, a 50% fill formed a 'rippling' biofilm and a 30% fill formed a 'porous' biofilm. The highest microbial activity was obtained with a 50% carrier fill supporting a relatively thin biofilm. The highest level of biofilm bound metals were aluminium, silicon, calcium and iron in the 'compact' biofilm; nitrogen, magnesium, chloride, sodium and potassium in the 'rippling' biofilm, and copper in the 'porous' biofilm. The bioreactor improved the quality of the CGWW by removing 49% and 78% of the COD and phenols, respectively. However, no significant amount of ammonia-nitrogen was removed since nitrification did not take place due to heterotrophic bacteria out-competing autotrophic nitrifying bacteria in the biofilm. The dominant heterotrophic genera identified for all three carrier filling ratios were Thauera, Pseudaminobacter, Pseudomonas and Diaphorobacter.}, } @article {pmid27190803, year = {2016}, author = {Udayalaxmi, J and Shenoy, N}, title = {Comparison Between Biofilm Production, Phospholipase and Haemolytic Activity of Different Species of Candida Isolated from Dental Caries Lesions in Children.}, journal = {Journal of clinical and diagnostic research : JCDR}, volume = {10}, number = {4}, pages = {DC21-3}, pmid = {27190803}, issn = {2249-782X}, abstract = {INTRODUCTION: C.albicans is the most commonly isolated fungal pathogen in the oral cavity, but isolation of non-albicans Candida is increasing in recent years. We wish to demonstrate the virulence factors of Candida spp. isolated from the dental caries lesion of the children as presence of virulence factors determines the pathogenic potential of any microorganism.

AIM: To compare biofilm production, phospholipase and haemolytic activity of C.albicans with that of non-albicans species of Candida isolated from dental caries lesions of children to evaluate the role of non- albicans species of Candida in formation of dental caries.

MATERIALS AND METHODS: Oral swabs were collected from caries lesion of 100 school children of age 5-10 years with dental caries. Candida isolates were tested for biofilm production, phospholipase and haemolytic activity. Statistical analysis was done by Chi-Square test and Mann-Whitney U test wherever applicable using SPSS version 11.5.

RESULTS: Out of the 100 children with dental caries 37 were positive for Candida by smear or culture and 31 by culture. C.albicans was the most prevalent isolate followed by C.krusei, C.tropicalis and C.albicans. Out of 21 C.albicans isolates, 10 (47.6%) showed phospholipase activity and 18 (85.71%) produced biofilm. Of the 10 non-albicans strains, 5 (50%) showed phospholipase activity and 6 (60%) produced biofilm. All isolates of Candida produced haemolysin (100%).

CONCLUSION: There was no statistically relevant difference between the virulence factor production by C.albicans and non-albicans species of Candida. In other words, our study shows that both C.albicans and non-albicans species of Candida isolated from caries lesions of the children, produce these virulence factors. So we can say that non-albicans species of Candida also are involved in caries formation.}, } @article {pmid27190540, year = {2016}, author = {Yang, Y and Park, BI and Hwang, EH and You, YO}, title = {Composition Analysis and Inhibitory Effect of Sterculia lychnophora against Biofilm Formation by Streptococcus mutans.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2016}, number = {}, pages = {8163150}, pmid = {27190540}, issn = {1741-427X}, abstract = {Pangdahai is a traditional Chinese drug, specifically described in the Chinese Pharmacopoeia as the seeds of Sterculia lychnophora Hance. Here, we separated S. lychnophora husk and kernel, analyzed the nutrient contents, and investigated the inhibitory effects of S. lychnophora ethanol extracts on cariogenic properties of Streptococcus mutans, important bacteria in dental caries and plaque formation. Ethanol extracts of S. lychnophora showed dose-dependent antibacterial activity against S. mutans with significant inhibition at concentrations higher than 0.01 mg/mL compared with the control group (p < 0.05). Furthermore, biofilm formation was decreased by S. lychnophora at concentrations > 0.03 mg/mL, while bacterial viability was decreased dose-dependently at high concentrations (0.04, 0.08, 0.16, and 0.32 mg/mL). Preliminary phytochemical analysis of the ethanol extract revealed a strong presence of alkaloid, phenolics, glycosides, and peptides while the presence of steroids, terpenoids, flavonoids, and organic acids was low. The S. lychnophora husk had higher moisture and ash content than the kernel, while the protein and fat content of the husk were lower (p < 0.05) than those of the kernel. These results indicate that S. lychnophora may have antibacterial effects against S. mutans, which are likely related to the alkaloid, phenolics, glycosides, and peptides, the major components of S. lychnophora.}, } @article {pmid27190164, year = {2016}, author = {Uhlich, GA and Chen, CY and Cottrell, BJ and Hofmann, CS and Yan, X and Nguyen, L}, title = {Stx1 prophage excision in Escherichia coli strain PA20 confers strong curli and biofilm formation by restoring native mlrA.}, journal = {FEMS microbiology letters}, volume = {363}, number = {13}, pages = {}, doi = {10.1093/femsle/fnw123}, pmid = {27190164}, issn = {1574-6968}, mesh = {Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Coliphages/genetics ; Congo Red/metabolism ; DNA, Bacterial/genetics ; Escherichia coli O157/*genetics/*physiology ; Escherichia coli Proteins/*genetics/metabolism ; Fimbriae, Bacterial/metabolism ; Gene Expression Profiling ; Genes, Regulator ; Genomics ; Mutation ; Phenotype ; Prophages/*genetics ; Shiga Toxin 1/*genetics ; Trans-Activators/genetics/metabolism ; Virus Activation ; }, abstract = {Prophage insertions in Escherichia coli O157:H7 mlrA contribute to the low expression of curli fimbriae and biofilm observed in many clinical isolates. Varying levels of CsgD-dependent curli/biofilm expression are restored to strains bearing prophage insertions in mlrA by mutation of regulatory genes affecting csgD Our previous study identified strong biofilm- and curli-producing variants in O157:H7 cultures that had lost the mlrA-imbedded prophage characteristic of the parent population, suggesting prophage excision as a mechanism for restoring biofilm properties. In this study, we compared genomic, transcriptomic and phenotypic properties of parent strain PA20 (stx1, stx2) and its prophage-cured variant, 20R2R (stx2), and confirmed the mechanism underlying the differences in biofilm formation.}, } @article {pmid27190143, year = {2016}, author = {López-Sánchez, A and Leal-Morales, A and Jiménez-Díaz, L and Platero, AI and Bardallo-Pérez, J and Díaz-Romero, A and Acemel, RD and Illán, JM and Jiménez-López, J and Govantes, F}, title = {Biofilm formation-defective mutants in Pseudomonas putida.}, journal = {FEMS microbiology letters}, volume = {363}, number = {13}, pages = {}, doi = {10.1093/femsle/fnw127}, pmid = {27190143}, issn = {1574-6968}, mesh = {Adhesins, Bacterial/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Cell Membrane/metabolism ; Flagella/metabolism ; Gene Expression Regulation, Bacterial ; *Mutation ; Periplasm/metabolism ; Pseudomonas putida/*genetics/isolation & purification/physiology ; }, abstract = {Out of 8000 candidates from a genetic screening for Pseudomonas putida KT2442 mutants showing defects in biofilm formation, 40 independent mutants with diminished levels of biofilm were analyzed. Most of these mutants carried insertions in genes of the lap cluster, whose products are responsible for synthesis, export and degradation of the adhesin LapA. All mutants in this class were strongly defective in biofilm formation. Mutants in the flagellar regulatory genes fleQ and flhF showed similar defects to that of the lap mutants. On the contrary, transposon insertions in the flagellar structural genes fliP and flgG, that also impair flagellar motility, had a modest defect in biofilm formation. A mutation in gacS, encoding the sensor element of the GacS/GacA two-component system, also had a moderate effect on biofilm formation. Additional insertions targeted genes involved in cell envelope function: PP3222, encoding the permease element of an ABC-type transporter and tolB, encoding the periplasmic component of the Tol-OprL system required for outer membrane stability. Our results underscore the central role of LapA, suggest cross-regulation between motility and adhesion functions and provide insights on the role of cell envelope trafficking and maintenance for biofilm development in P. putida.}, } @article {pmid27189338, year = {2017}, author = {Liu, Z and Lin, Y and Lu, Q and Li, F and Yu, J and Wang, Z and He, Y and Song, C}, title = {In vitro and in vivo activity of EDTA and antibacterial agents against the biofilm of mucoid Pseudomonas aeruginosa.}, journal = {Infection}, volume = {45}, number = {1}, pages = {23-31}, pmid = {27189338}, issn = {1439-0973}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Disease Models, Animal ; Edetic Acid/*pharmacology/therapeutic use ; Guinea Pigs ; Pneumonia, Bacterial/drug therapy ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {PURPOSE: Refractory infection caused by bacterial biofilm is an important clinical problem. Pseudomonas aeruginosa is a common pathogen responsible for persistent and chronic biofilm infections. We aimed to explore the in vitro and in vivo activity of ethylenediamine tetraacetic acid (EDTA) in combination with antibacterial agents against mucoid P. aeruginosa biofilm.

METHODS: The minimal inhibitory concentration (MIC) and minimal bactericidal concentration of ciprofloxacin, gentamicin, and ampicillin alone or with EDTA against P. aeruginosa were determined in vitro. Extracellular polysaccharides (EPS) and structural parameters of the biofilm were monitored. P. aeruginosa was aerosolized and delivered into the lungs of guinea pigs, which were treated with ciprofloxacin with or without EDTA. The colony-forming units (CFUs) of P. aeruginosa were determined from the lungs.

RESULTS: EDTA reduced the MIC of ciprofloxacin and ampicillin by about 30-fold and that of gentamicin by twofold. EDTA reduced the biofilm EPS and the proportion of viable bacteria. The thickness, average diffusion distance, and textural entropy of EDTA-treated biofilm were significantly decreased. EDTA plus antibiotics reduced the colony counting from 10[7] to 10[3] CFU/mL. In vivo, EDTA plus ciprofloxacin had a significantly lower mean CFU/g of lung tissue (EDTA + ciprofloxacin 1.3 ± 0.19; EDTA 4.4 ± 0.57; ciprofloxacin 4.2 ± 0.47), and lung lesions were less severe compared with the single treatment groups.

CONCLUSIONS: EDTA can destroy the biofilm structures of mucoid P. aeruginosa in vitro. Moreover, EDTA and ciprofloxacin had a significant bactericidal effect against biofilm in vivo.}, } @article {pmid27188522, year = {2016}, author = {Sulzberger, M and Fölster, H and Sattler, M and Rippke, F and Grönniger, E}, title = {Inhibition of Propionibacterium acnes associated biofilm formation by Decanediol.}, journal = {Journal of dermatological science}, volume = {83}, number = {2}, pages = {159-161}, doi = {10.1016/j.jdermsci.2016.05.003}, pmid = {27188522}, issn = {1873-569X}, mesh = {Acne Vulgaris/*drug therapy/microbiology ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Biofilms/*drug effects ; Cosmetics/*pharmacology/therapeutic use ; Glycols/*pharmacology/therapeutic use ; Humans ; Propionibacterium acnes/*drug effects/physiology ; }, } @article {pmid27187050, year = {2016}, author = {Wang, Y and Bott, C and Nerenberg, R}, title = {Sulfur-based denitrification: Effect of biofilm development on denitrification fluxes.}, journal = {Water research}, volume = {100}, number = {}, pages = {184-193}, doi = {10.1016/j.watres.2016.05.020}, pmid = {27187050}, issn = {1879-2448}, mesh = {Biofilms ; Bioreactors ; *Denitrification ; Nitrates ; *Sulfur ; }, abstract = {Elemental sulfur (S(o)) can serve as an electron donor for denitrification. However, the mechanisms and rates of S(o)-based denitrification, which depend on a biofilm development on a solid S(o) surface, are not well understood. We used completely-mixed reactors packed with S(o) chips to systematically explore the behavior of S(o)-based denitrification as a function of the bulk nitrate (NO3(-)) concentration and biofilm development. High-purity (99.5%) and agricultural-grade (90% purity) S(o) chips were tested to explore differences in performance. NO3(-) fluxes followed a Monod-type relationship with the bulk NO3(-) concentration. For high-purity S(o), the maximum NO3(-) flux increased from 0.4 gN/m(2)-d at 21 days to 0.9 g N/m(2)-d at around 100 days, but then decreased to 0.65 gN/m(2)-d at 161 days. The apparent (extant) half-saturation constant for NO3(-) KSapp, based on the bulk NO3(-) concentration and NO3(-) fluxes into the biofilm, increased from 0.1 mgN/L at 21 days to 0.8 mgN/L at 161 days, reflecting the increasing mass transfer resistance as the biofilm thickness increased. Nitrite (NO2(-)) accumulation became significant at bulk NO3(-) concentration above 0.2 mgN/L. The behavior of the agricultural-grade S(o) was very similar to the high-purity S(o). The kinetic behavior of S(o)-based denitrification was consistent with substrate counter-diffusion, where the soluble sulfur species diffuse from the S(o) particle into the base of the biofilm, while NO3(-) diffuses into the biofilm from the bulk. Initially, the fluxes were low due to biomass limitation (thin biofilms). As the biofilm thickness increased with time, the fluxes first increased, stabilized, and then decreased. The decrease was probably due to increasing diffusional resistance in the thick biofilm. Results suggest that fluxes comparable to heterotrophic biofilm processes can be achieved, but careful management of biofilm accumulation is important to maintain high fluxes.}, } @article {pmid27186636, year = {2016}, author = {Azizi, S and Kamika, I and Tekere, M}, title = {Evaluation of Heavy Metal Removal from Wastewater in a Modified Packed Bed Biofilm Reactor.}, journal = {PloS one}, volume = {11}, number = {5}, pages = {e0155462}, pmid = {27186636}, issn = {1932-6203}, mesh = {*Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; *Bioreactors ; *Metals, Heavy ; Microbiota ; Quality Control ; Wastewater/*chemistry ; *Water Pollutants, Chemical ; }, abstract = {For the effective application of a modified packed bed biofilm reactor (PBBR) in wastewater industrial practice, it is essential to distinguish the tolerance of the system for heavy metals removal. The industrial contamination of wastewater from various sources (e.g. Zn, Cu, Cd and Ni) was studied to assess the impacts on a PBBR. This biological system was examined by evaluating the tolerance of different strengths of composite heavy metals at the optimum hydraulic retention time (HRT) of 2 hours. The heavy metal content of the wastewater outlet stream was then compared to the source material. Different biomass concentrations in the reactor were assessed. The results show that the system can efficiently treat 20 (mg/l) concentrations of combined heavy metals at an optimum HRT condition (2 hours), while above this strength there should be a substantially negative impact on treatment efficiency. Average organic reduction, in terms of the chemical oxygen demand (COD) of the system, is reduced above the tolerance limits for heavy metals as mentioned above. The PBBR biological system, in the presence of high surface area carrier media and a high microbial population to the tune of 10 000 (mg/l), is capable of removing the industrial contamination in wastewater.}, } @article {pmid27185827, year = {2016}, author = {Taglialegna, A and Lasa, I and Valle, J}, title = {Amyloid Structures as Biofilm Matrix Scaffolds.}, journal = {Journal of bacteriology}, volume = {198}, number = {19}, pages = {2579-2588}, pmid = {27185827}, issn = {1098-5530}, mesh = {Amyloid/*chemistry ; Bacterial Proteins/*physiology ; Biofilms/*growth & development ; DNA, Bacterial ; Gene Expression Regulation, Bacterial ; }, abstract = {Recent insights into bacterial biofilm matrix structures have induced a paradigm shift toward the recognition of amyloid fibers as common building block structures that confer stability to the exopolysaccharide matrix. Here we describe the functional amyloid systems related to biofilm matrix formation in both Gram-negative and Gram-positive bacteria and recent knowledge regarding the interaction of amyloids with other biofilm matrix components such as extracellular DNA (eDNA) and the host immune system. In addition, we summarize the efforts to identify compounds that target amyloid fibers for therapeutic purposes and recent developments that take advantage of the amyloid structure to engineer amyloid fibers of bacterial biofilm matrices for biotechnological applications.}, } @article {pmid27185376, year = {2016}, author = {She, P and Chen, L and Qi, Y and Xu, H and Liu, Y and Wang, Y and Luo, Z and Wu, Y}, title = {Effects of human serum and apo-Transferrin on Staphylococcus epidermidis RP62A biofilm formation.}, journal = {MicrobiologyOpen}, volume = {5}, number = {6}, pages = {957-966}, pmid = {27185376}, issn = {2045-8827}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/drug effects/*growth & development ; Drug Synergism ; Humans ; Immune Sera/*pharmacology ; Microbial Sensitivity Tests ; Staphylococcal Infections/*drug therapy/microbiology ; Staphylococcus epidermidis/*growth & development ; Transferrin/*pharmacology ; Vancomycin/*pharmacology ; }, abstract = {Biofilm-associated Staphylococcus epidermidis infections present clinically important features due to their high levels of resistance to traditional antibiotics. As a part of human innate immune system, serum shows different degrees of protection against systemic S. epidermidis infection. We investigated the ability of human serum as well as serum component to inhibit the formation of, and eradication of mature S. epidermidis biofilms. In addition, the synergistic effect of vancomycin combined with apo-Transferrin was checked. Human serum exhibited significant antibiofilm activities against S. epidermidis at the concentration without affecting planktonic cell growth. However, there was no effect of human serum on established biofilms. By component separation, we observed that antibiofilm effect of serum components mainly due to the proteins could be damaged by heat inactivation (e.g., complement) or heat-stable proteins ≥100 kDa. In addition, serum apo-Transferrin showed modest antibiofilm effect, but without influence on S. epidermidis initial adhesion. And there was a synergistic antibiofilm interaction between vancomycin and apo-Transferrin against S. epidermidis. Our results indicate that serum or its components (heat-inactivated components or heat-stable proteins ≥100 kDa) could inhibits S. epidermidis biofilm formation. Besides, apo-Transferrin could partially reduce the biofilm formation at the concentration that does not inhibit planktonic cell growth.}, } @article {pmid27185296, year = {2016}, author = {Wang, H and Yan, Y and Rong, D and Wang, J and Wang, H and Liu, Z and Wang, J and Yang, R and Han, Y}, title = {Increased biofilm formation ability in Klebsiella pneumoniae after short-term exposure to a simulated microgravity environment.}, journal = {MicrobiologyOpen}, volume = {5}, number = {5}, pages = {793-801}, pmid = {27185296}, issn = {2045-8827}, mesh = {Agglutination/physiology ; Biofilms/*growth & development ; Cellulose/metabolism ; Fimbriae, Bacterial/*metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Klebsiella pneumoniae/*growth & development/metabolism/pathogenicity ; Space Flight ; *Weightlessness ; Yeasts/metabolism ; }, abstract = {Biofilm formation is closely related to the pathogenetic processes of Klebsiella pneumoniae, which frequently causes infections in immunocompromised individuals. The immune system of astronauts is compromised in spaceflight. Accordingly, K. pneumoniae, which used to be isolated from orbiting spacecraft and astronauts, poses potential threats to the health of astronauts and mission security. Microgravity is a key environmental cue during spaceflight. Therefore, determining its effects on bacterial biofilm formation is necessary. In this study, K. pneumoniae ATCC BAA-1705 was exposed to a simulated microgravity (SMG) environment. K. pneumoniae grown under SMG formed thicker biofilms compared with those under normal gravity (NG) control after 2 weeks of subculture. Two indicative dyes (i.e., Congo red and calcofluor) specifically binding to cellulose fibers and/or fimbriae were utilized to reconfirm the enhanced biofilm formation ability of K. pneumoniae grown under SMG. Further analysis showed that the biofilms formed by SMG-treated K. pneumoniae were susceptible to cellulase digestion. Yeast cells mannose-resistant agglutination by K. pneumoniae type 3 fimbriae was more obvious in the SMG group, which suggests that cellulose production and type 3 fimbriae expression in K. pneumoniae were both enhanced under the SMG condition. Transcriptomic analysis showed that 171 genes belonging to 15 functional categories were dysregulated in this organism exposed to the SMG conditions compared with those in the NG group, where the genes responsible for the type 3 fimbriae (mrkABCDF) and its regulator (mrkH) were upregulated.}, } @article {pmid27184127, year = {2016}, author = {Song, B and Wang, YZ and Wang, GY and Liu, GL and Li, WZ and Yan, F}, title = {The lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA has potent activity against the biofilm-forming organisms.}, journal = {Marine pollution bulletin}, volume = {108}, number = {1-2}, pages = {62-69}, doi = {10.1016/j.marpolbul.2016.04.062}, pmid = {27184127}, issn = {1879-3363}, mesh = {*Bacillus amyloliquefaciens ; *Biofilms ; *Lipopeptides ; Pseudomonas aeruginosa ; }, abstract = {Both the whole cells and protoplasts of Pseudomonas aeruginosa PAO1 and Bacillus cereus, two biofilm-forming bacteria, were disrupted by the lipopeptide 6-2 produced by Bacillus amyloliquefaciens anti-CA. The lipopeptide 6-2 could also effectively inhibit the formation of biofilms and disperse pre-formed biofilms. Live/dead staining of the biofilms grown in the absence or presence of the lipopeptide 6-2 showed that more dead bacterial cells in the presence of the lipopeptide than those in the absence of the lipopeptide and biofilm formation was greatly reduced by the lipopeptide 6-2. Expression of the PslC gene related to exopolysaccharides in P. aeruginosa PAO1 was also inhibited. All these results demonstrated that the lipopeptide 6-2 produced by B. amyloliquefaciens anti-CA had a high activity against biofilm-forming bacteria. The lipopeptide 6-2 also killed the larvae of Balanus amphitrite and inhibit the germination of Laminaria japonica spore and growth of protozoa, all of which were the fouling organisms in marine environments.}, } @article {pmid27183731, year = {2016}, author = {Leonov, VV and Mironov, AY}, title = {[THE FORMATION OF BIOFILM IN OPPORTUNISTIC MICROORGANISMS IN BLOOD PLASMA DEPENDING ON CONTENT OF IRON].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {61}, number = {1}, pages = {52-54}, pmid = {27183731}, issn = {0869-2084}, mesh = {Adult ; Biofilms/*drug effects/growth & development ; Escherichia coli/drug effects/isolation & purification/*physiology ; Escherichia coli Infections/microbiology ; Humans ; Iron/*blood/pharmacology ; Male ; Opportunistic Infections/microbiology ; Polysaccharides, Bacterial/biosynthesis ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/drug effects/isolation & purification/*physiology ; Russia ; Spectroscopy, Fourier Transform Infrared ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/drug effects/isolation & purification/*physiology ; }, abstract = {The article considers results of analysis offormation of biofilm of priority opportunistic pathogens in blood plasma and LB-broth. As compared with LB-broth, bloodplasma stimulates formation of biofilm of microorganisms in the following sequence: Staphylococcus aureus > Pseudomonas aeruginosa > Escherichia coli. The application oftechnique of infra-redspectroscopy of bio-films established that blood plasma promotes formation of external exopolysaccharides of S.aureus. The cultivation of bio-films in plasma depending on content of iron demonstrated that the analyzed strains of S. aureus, P. aeruginosa, E. coli form bio-films in a better way in plasma with normal content of iron and iron-deficient and iron-loaded plasma decreases their activity of formation of biofilm.}, } @article {pmid27183234, year = {2016}, author = {Li, Y and Zhou, J and Gong, B and Wang, Y and He, Q}, title = {Cometabolic degradation of lincomycin in a Sequencing Batch Biofilm Reactor (SBBR) and its microbial community.}, journal = {Bioresource technology}, volume = {214}, number = {}, pages = {589-595}, doi = {10.1016/j.biortech.2016.04.085}, pmid = {27183234}, issn = {1873-2976}, mesh = {Bacteria/metabolism ; Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/*microbiology ; Lincomycin/*metabolism ; Oxidation-Reduction ; Waste Disposal, Fluid/methods ; Wastewater/*microbiology ; }, abstract = {Cometabolism technology was employed to degrade lincomycin wastewater in Sequencing Batch Biofilm Reactor (SBBR). In contrast with the control group, the average removal rate of lincomycin increased by 56.0% and Total Organic Carbon (TOC) increased by 52.5% in the cometabolic system with glucose as growth substrate. Under the same condition, Oxidation-Reduction Potential (ORP) was 85.1±7.3mV in cometabolic system and 198.2±8.4mV in the control group, indicating that glucose changed the bulk ORP and created an appropriate growing environment for function bacteria. Functional groups of lincomycin were effectively degraded in cometabolic system proved by FTIR and GC-MS. Meanwhile, results of DGGE and 16S rDNA showed great difference in dominant populations between cometabolic system and the control group. In cometabolic system, Roseovarius (3.35%), Thiothrix (2.74%), Halomonas (2.49%), Ignavibacterium (2.02%), and TM7_genus_incertae_sedis (1.93%) were verified as dominant populations at genus level. Cometabolism may be synergistically caused by different functional dominant bacteria.}, } @article {pmid27183085, year = {2016}, author = {Saffarpour, A and Fekrazad, R and Heibati, MN and Bahador, A and Saffarpour, A and Rokn, AR and Iranparvar, A and KharaziFard, MJ}, title = {Bactericidal Effect of Erbium-Doped Yttrium Aluminum Garnet Laser and Photodynamic Therapy on Aggregatibacter Actinomycetemcomitans Biofilm on Implant Surface.}, journal = {The International journal of oral & maxillofacial implants}, volume = {31}, number = {3}, pages = {e71-8}, doi = {10.11607/jomi.4224}, pmid = {27183085}, issn = {1942-4434}, mesh = {*Aggregatibacter actinomycetemcomitans/drug effects/radiation effects ; Aluminum ; Analysis of Variance ; Anti-Bacterial Agents ; Anti-Infective Agents, Local/*therapeutic use ; *Biofilms/drug effects/radiation effects ; Chlorhexidine/*therapeutic use ; Colony Count, Microbial ; Dental Implants/*microbiology ; Disinfection/methods ; Erbium ; Laser Therapy/*methods ; Lasers, Semiconductor ; Lasers, Solid-State/*therapeutic use ; Pasteurellaceae Infections/*therapy ; Peri-Implantitis/*therapy ; Photochemotherapy/*methods ; Tolonium Chloride ; Yttrium ; }, abstract = {PURPOSE: Peri-implantitis is a common complication of dental implants. The first step of treatment is elimination of bacterial biofilm and disinfection of the implant surface. This study sought to compare the effects of an erbium-doped yttrium aluminum garnet (Er:YAG) laser, photodynamic therapy using an indocyanin green-based photosensitizer (ICG-based PS) and diode laser, toluidine blue O (TBO) photosensitizer and light-emitting diode (LED) light source, and 2% chlorhexidine (CHX) on biofilm of Aggregatibacter actinomycetemcomitans to sandblasted, large-grit, acid-etched (SLA) implant surfaces.

MATERIALS AND METHODS: Fifty SLA implants were divided into five groups and were incubated with A actinomycetemcomitans bacteria to form bacterial biofilm. Group 1 underwent Er:YAG laser radiation (with 10-Hz frequency, 100-mJ energy, and 1-W power); group 2 was subjected to LED (with 630-nm wavelength and maximum output intensity of 2.000 to 4.000 mW/cm(2)) and TBO as a photosensitizer; group 3 was exposed to diode laser radiation (with 810-nm wavelength and 300-mW power) and ICG-based PS; and group 4 was immersed in 2% CHX. Group 5 was the control group, and the samples were rinsed with normal saline. The number of colony-forming units (CFU) per implant was then calculated. Data were analyzed using one-way analysis of variance (ANOVA), and the five groups were compared.

RESULTS: Significant differences was found between the control group and the other groups (P < .01). The lowest mean of CFU per implant count was in group 4 (P < .01), and the highest mean belonged to the control group. Photodynamic therapy by TBO + LED and ICG-based PS + diode laser was more effective than Er:YAG laser irradiation in suppression of this organism (P < .01). There was no significant difference between groups 2 and 3.

CONCLUSION: The antibacterial effect of 2% CHX was greater than that of other understudy methods.}, } @article {pmid27175857, year = {2016}, author = {von Salm, JL and Witowski, CG and Fleeman, RM and McClintock, JB and Amsler, CD and Shaw, LN and Baker, BJ}, title = {Darwinolide, a New Diterpene Scaffold That Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm from the Antarctic Sponge Dendrilla membranosa.}, journal = {Organic letters}, volume = {18}, number = {11}, pages = {2596-2599}, pmid = {27175857}, issn = {1523-7052}, support = {R01 AI080626/AI/NIAID NIH HHS/United States ; R21 AI103715/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Antarctic Regions ; Anti-Bacterial Agents/*chemistry/isolation & purification/pharmacology ; Biofilms/*drug effects ; Cell Line ; Diterpenes/*chemistry/isolation & purification/pharmacology ; Inhibitory Concentration 50 ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development ; Mice ; Microbial Sensitivity Tests ; Molecular Structure ; Porifera/chemistry ; }, abstract = {A new rearranged spongian diterpene, darwinolide, has been isolated from the Antarctic Dendroceratid sponge Dendrilla membranosa. Characterized on the basis of spectroscopic and crystallographic analysis, the central seven-membered ring is hypothesized to originate from a ring-expansion of a spongian precursor. Darwinolide displays 4-fold selectivity against the biofilm phase of methicillin-resistant Staphylococcus aureus compared to the planktonic phase and may provide a scaffold for the development of therapeutics for this difficult to treat infection.}, } @article {pmid27175498, year = {2016}, author = {Aslan, H and Gülmez, D}, title = {[Investigation of the correlation between biofilm forming ability of urinary Candida isolates with the use of urinary catheters and change of antifungal susceptibility in the presence of biofilm].}, journal = {Mikrobiyoloji bulteni}, volume = {50}, number = {2}, pages = {256-265}, doi = {10.5578/mb.24248}, pmid = {27175498}, issn = {0374-9096}, mesh = {Antifungal Agents/*pharmacology/therapeutic use ; Biofilms/drug effects/*growth & development ; Candida/drug effects/isolation & purification/*physiology ; Cross Infection/*microbiology ; Humans ; Intensive Care Units ; Urinary Catheters/*microbiology ; Urinary Tract Infections/*microbiology ; }, abstract = {Frequency of Candida species causing urinary tract infections is increasing, and this increase is outstanding in nosocomial urinary tract infections especially in intensive care units. The ability of biofilm formation that is contributed to the virulence of the yeast, plays a role in the pathogenesis of biomaterial-related infections and also constitutes a risk for treatment failure. The aims of this study were to compare biofilm forming abilities of Candida strains isolated from urine cultures of patients with and without urinary catheters, and to investigate the change of antifungal susceptibility in the presence of biofilm. A total of 50 Candida strains isolated from urine cultures of 25 patients with urinary catheters (10 C.tropicalis, 6 C.glabrata, 4 C.albicans, 4 C.parapsilosis, 1 C.krusei) and 25 without urinary catheters (8 C.tropicalis, 6 C.albicans, 4 C.krusei, 3 C.parapsilosis, 2 C.kefyr, 1 C.glabrata, 1 C.lusitaniae) were included in the study. Biofilm forming ability was tested by Congo red agar (CRA) and microplate XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction methods. Fluconazole (FLU) and amphotericin B (AMP-B) susceptibilities of the isolates were determined by reference microdilution method recommended by Clinical and Laboratory Standards Institute for planktonic cells and by XTT reduction assay in case of biofilm presence. Biofilm formation was detected in 12 (24%) by CRA and 50 (100%) of the isolates by XTT reduction method. None of the C.albicans (n= 10) and C.tropicalis (n= 18) strains were detected as biofilm positive by CRA, however, these strains were strongly positive by XTT reduction method. No statistically significant correlation was detected between the presence of urinary catheter and biofilm forming ability of the isolate (p> 0.05). This might be caused by the advantage of biofilm forming strains in adhesion to bladder mucosa at the initial stages of infection. For all of the isolates in planktonic form, minimum inhibitory concentration (MIC) values were below the clinical resistance breakpoints or epidemiological cut-off values. When tested in presence of biofilms, all the isolates became resistant aganist FLU. Similarly, 100% inhibition, which is recommended in the standard method to determine AMP-B MIC, could not be obtained in any of the isolates with the highest dilution 8 µg/ml AMP-B tested. When evaluation was performed according to 80% inhibition, only 14 (28%) of the isolates had an AMP-B MIC below species-specific epidemiological cut-off values in the presence of biofilm. As a result, no correlation between urinary catheters and biofilm formation ability of Candida isolates were detected. XTT reduction method was considered as more reliable than CRA for investigating biofilm formation of Candida species. In addition, CRA failed to detect biofilm formation in frequently isolated species such as C.albicans and C.tropicalis. Fluconazole activity was lost, while AMP-B could not provide 100% inhibition in presence of biofilm for all isolates tested. Even if 80% inhibition was taken into account, AMP-B activity was still variable according to strain.}, } @article {pmid27175186, year = {2015}, author = {Gulhan, T and Boynukara, B and Ciftci, A and Sogut, MU and Findik, A}, title = {Characterization of Enterococcus faecalis isolates originating from different sources for their virulence factors and genes, antibiotic resistance patterns, genotypes and biofilm production.}, journal = {Iranian journal of veterinary research}, volume = {16}, number = {3}, pages = {261-266}, pmid = {27175186}, issn = {1728-1997}, abstract = {In this study, 72 Enterococcus faecalis isolates originating from humans (n=39), dogs (n=26) and cats (n=7) were investigated for some virulence factors, some virulence genes, antibiotic resistance phenotypes, randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) patterns and biofilm production. Of the isolates, 31 (43.1%) were positive for gelatinase, 11 (15.3%) for aggregation substance and cytolysine, 38 (52.8%) for gelE and 34 (47.2%) for asa1 genes. All isolates were found to be negative for hyl, esp and cylA genes. All isolates were found to be resistant to nalidixic acid and kanamycin. On the other hand, all isolates were cited for susceptible to amoxicillin. Vancomycin resistance genes (vanA, vanB, vanC1/C2 or vanD) have not been detected in any of the phenotypically vancomycin resistant isolates. Isolates from humans, dogs and cats were grouped into 8, 2 and 4 antibiotypes depending upon susceptibilities to 12 different antibiotics. In all human, dog and cat isolates, 9, 12 and 2 genotypes were determined by RAPD-PCR, respectively. Nine (34.6%) of the dog isolates were found to be positive for biofilm production. This study showed that multiple antibiotic resistance among human isolates is more frequent than in dog and cat isolates.}, } @article {pmid27174270, year = {2016}, author = {Wang, Z and Eddie, BJ and Malanoski, AP and Hervey, WJ and Lin, B and Strycharz-Glaven, SM}, title = {Complete Genome Sequence of Labrenzia sp. Strain CP4, Isolated from a Self-Regenerating Biocathode Biofilm.}, journal = {Genome announcements}, volume = {4}, number = {3}, pages = {}, pmid = {27174270}, issn = {2169-8287}, abstract = {Here, we present the complete genome sequence of Labrenzia sp. strain CP4, isolated from an electricity-consuming marine biocathode biofilm. Labrenzia sp. strain CP4 consists of a circular 5.2 Mbp chromosome and an 88 Kbp plasmid.}, } @article {pmid27170321, year = {2016}, author = {Wang, R and Xiao, F and Wang, Y and Lewandowski, Z}, title = {Determining the optimal transmembrane gas pressure for nitrification in membrane-aerated biofilm reactors based on oxygen profile analysis.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {17}, pages = {7699-7711}, doi = {10.1007/s00253-016-7553-1}, pmid = {27170321}, issn = {1432-0614}, mesh = {Ammonium Compounds/*metabolism ; Biofilms ; *Bioreactors ; *Membranes, Artificial ; Nitrification/physiology ; Oxygen/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry ; Water Purification/*methods ; }, abstract = {The goal of this study was to investigate the effect of transmembrane gas pressure (P g) on the specific ammonium removal rate in a membrane-aerated biofilm reactor (MABR). Our experimental results show that the specific ammonium removal rate increased from 4.98 to 9.26 gN m(-2) day(-1) when P g increased from 2 to 20 kPa in an MABR with a biofilm thickness of approximately 600 μm. However, this improvement was not linear; there was a threshold of P g separating the stronger and weaker effects of P g. The ammonium removal rate was improved less significantly when P g was over the threshold, indicating that there is an optimal threshold of P g for maximizing ammonium removal in an MABR. The change in oxygen penetration depth (d p) is less sensitive to P g in the ammonia-oxidizing active layer than in the inactive layer in membrane-aerated biofilm. The location of the P g threshold is at the same point as the thickness of the active layer on the curve of d p versus P g; thus, the active layer thickness and the optimal P g can be determined on the basis of the changes in the slope of d p to P g.}, } @article {pmid27170320, year = {2016}, author = {Hao, R and Meng, C and Li, J}, title = {An integrated process of three-dimensional biofilm-electrode with sulfur autotrophic denitrification (3DBER-SAD) for wastewater reclamation.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {16}, pages = {7339-7348}, doi = {10.1007/s00253-016-7534-4}, pmid = {27170320}, issn = {1432-0614}, mesh = {Autotrophic Processes ; Bacteria/*metabolism ; *Biodegradation, Environmental ; Biofilms ; Bioreactors/microbiology ; Carbon/*metabolism ; *Denitrification ; Electrodes ; Nitrogen/*metabolism ; Sulfur/*metabolism ; Wastewater/*chemistry ; Water Purification/*methods ; }, abstract = {A three-dimensional biofilm-electrode reactor (3DBER) was integrated with sulfur autotrophic denitrification (SAD) to improve nitrogen removal performance for wastewater reclamation. The impacts of influent carbon/nitrogen (C/N) ratio, electric current, and hydraulic retention time (HRT) were evaluated. The new process, abbreviated as 3DBER-SAD, achieved a more stable denitrification compared to the recently studied 3DBER in literature. Its nitrogen removal improved by about 45 % as compared to 3DBER, especially under low C/N ratio conditions. The results also revealed that the biofilm bacteria community of 3DBER-SAD contained 21.1 % of the genus Thauera, 19.3 % of the genus Thiobacillus and Sulfuricella, as well as 5.3 % of the genus Alicycliphilus, Pseudomonas, and Paracoccus. The synergy between these heterotrophic, sulfur autotrophic, and hydrogenotrophic denitrification bacteria was believed to cause the high and stable nitrogen removal performance under various operating conditions.}, } @article {pmid27169475, year = {2016}, author = {Lagos, ME and White, CR and Marshall, DJ}, title = {Biofilm history and oxygen availability interact to affect habitat selection in a marine invertebrate.}, journal = {Biofouling}, volume = {32}, number = {6}, pages = {645-655}, doi = {10.1080/08927014.2016.1178725}, pmid = {27169475}, issn = {1029-2454}, mesh = {Animals ; Biofilms/*growth & development ; Bryozoa/growth & development/metabolism/*physiology ; Ecosystem ; Invertebrates/physiology ; Larva/growth & development/metabolism/physiology ; Oxygen/*analysis ; Oxygen Consumption/physiology ; Seawater/chemistry ; Victoria ; }, abstract = {In marine systems, oxygen availability varies at small temporal and spatial scales, such that current oxygen levels may not reflect conditions of the past. Different studies have shown that marine invertebrate larvae can select settlement sites based on local oxygen levels and oxygenation history of the biofilm, but no study has examined the interaction of both. The influence of normoxic and hypoxic water and oxygenation history of biofilms on pre-settlement behavior and settlement of the bryozoan Bugula neritina was tested. Larvae used cues in a hierarchical way: the oxygen levels in the water prime larvae to respond, the response to different biofilms is contingent on oxygen levels in the water. When oxygen levels varied throughout biofilm formation, larvae responded differently depending on the history of the biofilm. It appears that B. neritina larvae integrate cues about current and historical oxygen levels to select the appropriate microhabitat and maximize their fitness.}, } @article {pmid27169388, year = {2016}, author = {Wagner-Döbler, I}, title = {Biofilm transplantation in the deep sea.}, journal = {Molecular ecology}, volume = {25}, number = {9}, pages = {1905-1907}, doi = {10.1111/mec.13612}, pmid = {27169388}, issn = {1365-294X}, mesh = {Bacteria/genetics ; *Biofilms ; Indian Ocean ; *Metagenome ; Microbiota ; }, abstract = {A gold rush is currently going on in microbial ecology, which is powered by the possibility to determine the full complexity of microbial communities through next-generation sequencing. Accordingly, enormous efforts are underway to describe microbiomes worldwide, in humans, animals, plants, soil, air and the ocean. While much can be learned from these studies, only experiments will finally unravel mechanisms. One of the key questions is how a microbial community is assembled from a pool of bacteria in the environment, and how it responds to change - be it the increase in CO2 concentration in the ocean, or antibiotic treatment of the gut microbiome. The study by Zhang et al. () in this issue is one of the very few that approaches this problem experimentally in the natural environment. The authors selected a habitat which is both extremely interesting and difficult to access. They studied the Thuwal Seep in the Red Sea at 850 m depth and used a remotely operated vehicle (ROV) to place a steel frame carrying substrata for biofilm growth into the brine pool and into the adjacent normal bottom water (NBW). Biofilms were allowed to develop for 3 days, and then those that had been growing in the brine pool were transported to normal bottom water and stayed there for another 3 days, and vice versa. The 'switched' biofilms were then compared with their source communities by metagenome sequencing. Strikingly, both 'switched' biofilms were now dominated by the same two species. These species were able to cope with conditions in both source ecosystems, as shown by assembly of their genomes and detection of expression of key genes. The biofilms had adapted to environmental change, rather than to brine pools or NBW. The study shows both the resilience and adaptability of biofilm communities and has implications for microbial ecology in general and even for therapeutic approaches such as transplantation of faecal microbiomes.}, } @article {pmid27169010, year = {2016}, author = {Aboualigalehdari, E and Sadeghifard, N and Taherikalani, M and Zargoush, Z and Tahmasebi, Z and Badakhsh, B and Rostamzad, A and Ghafourian, S and Pakzad, I}, title = {Anti-biofilm Properties of Peganum harmala against Candida albicans.}, journal = {Osong public health and research perspectives}, volume = {7}, number = {2}, pages = {116-118}, pmid = {27169010}, issn = {2210-9099}, abstract = {OBJECTIVES: Vaginitis still remains as a health issue in women. It is notable that Candida albicans producing biofilm is considered a microorganism responsible for vaginitis with hard to treat. Also, Peganum harmala was applied as an anti fungal in treatment for many infections in Iran. Therefore, this study goal to investigate the role of P. harmala in inhibition of biofilm formation in C. albicans.

METHODS: So, 27 C. albicans collected from women with Vaginitis, then subjected for biofilm formation assay. P. harmala was applied as antibiofilm formation in C. albicans.

RESULTS: Our results demonstrated that P. harmala in concentration of 12 μg/ml easily inhibited strong biofilm formation; while the concentrations of 10 and 6 μg/ml inhibited biofilm formation in moderate and weak biofilm formation C. albicans strains, respectively.

CONCLUSION: Hence, the current study presented P. harmala as antibiofilm herbal medicine for C. albicans; but in vivo study suggested to be performed to confirm its effectiveness.}, } @article {pmid27168369, year = {2016}, author = {Agostini, VO and Macedo, AJ and Muxagata, E}, title = {Evaluation of antibiotics as a methodological procedure to inhibit free-living and biofilm bacteria in marine zooplankton culture.}, journal = {Anais da Academia Brasileira de Ciencias}, volume = {88 Suppl 1}, number = {}, pages = {733-746}, doi = {10.1590/0001-3765201620150454}, pmid = {27168369}, issn = {1678-2690}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Copepoda/*drug effects/growth & development ; *Culture Media ; Drug Combinations ; Neomycin/pharmacology ; Penicillin G/pharmacology ; Streptomycin/pharmacology ; Zooplankton/*growth & development ; }, abstract = {There is a problem with keeping culture medium completely or partially free from bacteria. The use of prokaryotic metabolic inhibitors, such as antibiotics, is suggested as an alternative solution, although such substances should not harm non-target organisms. Thus, the aim of this study was to assess the effectiveness of antibiotic treatments in inhibiting free-living and biofilm bacteria and their half-life in artificial marine environment using the copepod Acartia tonsa as bioindicador of non-harmful antibiotic combinations. Regarding to results, the application of 0.025 g L-1 penicillin G potassium + 0.08 g L-1 streptomycin sulphate + 0.04 g L-1 neomycin sulphate showed great potential for use in marine cultures and scientific experiments without lethal effects to non-target organisms. The effect of this combination starts within the first six hours of exposure and reduces up to 93 % the bacterial density, but the half-life is short, requiring replacement. No adverse changes in water quality were observed within 168 hours of exposure. As a conclusion, we can infer that this treatment was an effective procedure for zooplankton cultures and scientific experiments with the aim of measuring the role of free-living and biofilm in the marine community.}, } @article {pmid27166035, year = {2016}, author = {Panda, PS and Chaudhary, U and Dube, SK}, title = {Comparison of four different methods for detection of biofilm formation by uropathogens.}, journal = {Indian journal of pathology & microbiology}, volume = {59}, number = {2}, pages = {177-179}, doi = {10.4103/0377-4929.182013}, pmid = {27166035}, issn = {0974-5130}, mesh = {Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Humans ; Prospective Studies ; Tertiary Care Centers ; Urinary Tract Infections/*microbiology ; }, abstract = {CONTEXT: Urinary tract infection (UTI) is one of the most common infectious diseases encountered in clinical practice. Emerging resistance of the uropathogens to the antimicrobial agents due to biofilm formation is a matter of concern while treating symptomatic UTI. However, studies comparing different methods for detection of biofilm by uropathogens are scarce.

AIMS: To compare four different methods for detection of biofilm formation by uropathogens.

SETTINGS AND DESIGN: Prospective observational study conducted in a tertiary care hospital.

MATERIALS AND METHODS: Totally 300 isolates from urinary samples were analyzed for biofilm formation by four methods, that is, tissue culture plate (TCP) method, tube method (TM), Congo Red Agar (CRA) method and modified CRA (MCRA) method.

STATISTICAL ANALYSIS: Chi-square test was applied when two or more set of variables were compared. P < 0.05 considered as statistically significant. Considering TCP to be a gold standard method for our study we calculated other statistical parameters.

RESULTS: The rate of biofilm detection was 45.6%, 39.3% and 11% each by TCP, TM, CRA and MCRA methods, respectively. The difference between TCP and only CRA/MCRA was significant, but not that between TCP and TM. There was no difference in the rate of biofilm detection between CRA and MCRA in other isolates, but MCRA is superior to CRA for detection of the staphylococcal biofilm formation.

CONCLUSIONS: TCP method is the ideal method for detection of bacterial biofilm formation by uropathogens. MCRA method is superior only to CRA for detection of staphylococcal biofilm formation.}, } @article {pmid27162389, year = {2016}, author = {Rohinishree, YS and Negi, PS}, title = {Effect of licorice extract on cell viability, biofilm formation and exotoxin production by Staphylococcus aureus.}, journal = {Journal of food science and technology}, volume = {53}, number = {2}, pages = {1092-1100}, pmid = {27162389}, issn = {0022-1155}, abstract = {Staphylococcus aureus is one of the most significant clinical pathogen, as it causes infections to humans and animals. Even though several antibiotics and other treatments have been used to control S. aureus infections and intoxication, bacterium is able to adapt, survive and produces exotoxins. Licorice (Glycyrrhiza glabra L.) has been used traditionally in various medicinal (antimicrobial) preparations, and Glycyrrhizic acid (GA) is the major active constituents present in it. In the present investigation the effect of licorice extract on methicillin susceptible S. aureus (FRI 722) and methicillin resistant S. aureus (ATCC 43300) growth and toxin production was studied. The MIC of licorice extract was found to be 0.25 and 2.5 mg GA ml(-1) against S. aureus FRI 722 and S. aureus ATCC 43300, respectively. Inhibition of biofilm formation was observed even at very low concentration (25 μg GA ml(-1)). Gradual decrease in expression and production of exotoxins such as α and β hemolysins and enterotoxin B was observed with the increasing concentrations of licorice extract, however, suboptimal concentration induced the expression of some of the virulence genes. This study indicated efficacy of licorice extract in controlling growth and pathogenicity of both methicillin susceptible and methicillin resistant S. aureus, however, the mechanisms of survival and toxin production at suboptimal concentration needs further study.}, } @article {pmid27161770, year = {2016}, author = {Lai, CY and Zhong, L and Zhang, Y and Chen, JX and Wen, LL and Shi, LD and Sun, YP and Ma, F and Rittmann, BE and Zhou, C and Tang, Y and Zheng, P and Zhao, HP}, title = {Bioreduction of Chromate in a Methane-Based Membrane Biofilm Reactor.}, journal = {Environmental science & technology}, volume = {50}, number = {11}, pages = {5832-5839}, doi = {10.1021/acs.est.5b06177}, pmid = {27161770}, issn = {1520-5851}, mesh = {Bacteria/metabolism ; *Biofilms ; Bioreactors/microbiology ; Chromates/*metabolism ; Chromium/metabolism ; Methane/metabolism ; Oxidation-Reduction ; }, abstract = {For the first time, we demonstrate chromate (Cr(VI)) bioreduction using methane (CH4) as the sole electron donor in a membrane biofilm reactor (MBfR). The experiments were divided into five stages lasting a total of 90 days, and each stage achieved a steady state for at least 15 days. Due to continued acclimation of the microbial community, the Cr(VI)-reducing capacity of the biofilm kept increasing. Cr(VI) removal at the end of the 90-day test reached 95% at an influent Cr(VI) concentration of 3 mg Cr/L and a surface loading of 0.37g of Cr m(-2) day(-1). Meiothermus (Deinococci), a potential Cr(VI)-reducing bacterium, was negligible in the inoculum but dominated the MBfR biofilm after Cr(VI) was added to the reactor, while Methylosinus, a type II methanotrophs, represented 11%-21% of the total bacterial DNA in the biofilm. Synergy within a microbial consortia likely was responsible for Cr(VI) reduction based on CH4 oxidation. In the synergy, methanotrophs fermented CH4 to produce metabolic intermediates that were used by the Cr(VI)-reducing bacteria as electron donors. Solid Cr(III) was the main product, accounting for more than 88% of the reduced Cr in most cases. Transmission electron microscope (TEM) and energy dispersive X-ray (EDS) analysis showed that Cr(III) accumulated inside and outside of some bacterial cells, implying that different Cr(VI)-reducing mechanisms were involved.}, } @article {pmid27161630, year = {2016}, author = {Klare, W and Das, T and Ibugo, A and Buckle, E and Manefield, M and Manos, J}, title = {Glutathione-Disrupted Biofilms of Clinical Pseudomonas aeruginosa Strains Exhibit an Enhanced Antibiotic Effect and a Novel Biofilm Transcriptome.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {8}, pages = {4539-4551}, pmid = {27161630}, issn = {1098-6596}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*drug effects ; Glutathione/*pharmacology ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/*drug effects ; Transcriptome/genetics ; }, abstract = {Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies.}, } @article {pmid27161114, year = {2016}, author = {Floyd, KA and Mitchell, CA and Eberly, AR and Colling, SJ and Zhang, EW and DePas, W and Chapman, MR and Conover, M and Rogers, BR and Hultgren, SJ and Hadjifrangiskou, M}, title = {The UbiI (VisC) Aerobic Ubiquinone Synthase Is Required for Expression of Type 1 Pili, Biofilm Formation, and Pathogenesis in Uropathogenic Escherichia coli.}, journal = {Journal of bacteriology}, volume = {198}, number = {19}, pages = {2662-2672}, pmid = {27161114}, issn = {1098-5530}, support = {R01 AI029549/AI/NIAID NIH HHS/United States ; R01 GM118651/GM/NIGMS NIH HHS/United States ; P50 DK064540/DK/NIDDK NIH HHS/United States ; F32 DK101171/DK/NIDDK NIH HHS/United States ; T32 GM007544/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Escherichia coli Proteins/genetics/*metabolism ; Female ; Fimbriae, Bacterial/*metabolism ; Gene Deletion ; Gene Expression Regulation, Bacterial/physiology ; Gene Expression Regulation, Enzymologic/physiology ; Membrane Potentials ; Mice ; Mice, Inbred C3H ; Mixed Function Oxygenases/genetics/*metabolism ; Mutation ; Urinary Tract Infections/*microbiology ; Uropathogenic Escherichia coli/genetics/*metabolism/pathogenicity ; Virulence ; }, abstract = {UNLABELLED: Uropathogenic Escherichia coli (UPEC), which causes the majority of urinary tract infections (UTI), uses pilus-mediated adherence to initiate biofilm formation in the urinary tract. Oxygen gradients within E. coli biofilms regulate expression and localization of adhesive type 1 pili. A transposon mutant screen for strains defective in biofilm formation identified the ubiI (formerly visC) aerobic ubiquinone synthase gene as critical for UPEC biofilm formation. In this study, we characterized a nonpolar ubiI deletion mutant and compared its behavior to that of wild-type bacteria grown under aerobic and anoxic conditions. Consistent with its function as an aerobic ubiquinone-8 synthase, deletion of ubiI in UPEC resulted in reduced membrane potential, diminished motility, and reduced expression of chaperone-usher pathway pili. Loss of aerobic respiration was previously shown to negatively impact expression of type 1 pili. To determine whether this reduction in type 1 pili was due to an energy deficit, wild-type UPEC and the ubiI mutant were compared for energy-dependent phenotypes under anoxic conditions, in which quinone synthesis is undertaken by anaerobic quinone synthases. Under anoxic conditions, the two strains exhibited wild-type levels of motility but produced diminished numbers of type 1 pili, suggesting that the reduction of type 1 pilus expression in the absence of oxygen is not due to a cellular energy deficit. Acute- and chronic-infection studies in a mouse model of UTI revealed a significant virulence deficit in the ubiI mutant, indicating that UPEC encounters enough oxygen in the bladder to induce aerobic ubiquinone synthesis during infection.

IMPORTANCE: The majority of urinary tract infections are caused by uropathogenic E. coli, a bacterium that can respire in the presence and absence of oxygen. The bladder environment is hypoxic, with oxygen concentrations ranging from 4% to 7%, compared to 21% atmospheric oxygen. This work provides evidence that aerobic ubiquinone synthesis must be engaged during bladder infection, indicating that UPEC bacteria sense and use oxygen as a terminal electron acceptor in the bladder and that this ability drives infection potential despite the fact that UPEC is a facultative anaerobe.}, } @article {pmid27157378, year = {2017}, author = {Guembe, M and Cruces, R and Peláez, T and Muñoz, P and Bouza, E and , }, title = {Assessment of biofilm production in Candida isolates according to species and origin of infection.}, journal = {Enfermedades infecciosas y microbiologia clinica}, volume = {35}, number = {1}, pages = {37-40}, doi = {10.1016/j.eimc.2016.04.003}, pmid = {27157378}, issn = {1578-1852}, mesh = {*Biofilms ; Candida/classification/*physiology ; Candidiasis/*microbiology ; Humans ; Mycology/methods ; Prospective Studies ; }, abstract = {The biofilm production (BP) of 200 clinical strains of Candida isolated during 2010-2013 were assessed using an in vitro model and a comparison of the results was made between species and between origins of the infections. The BP was assessed using the crystal violet assay, and the strains were classified as low, moderate, or high biofilm producers. Candida tropicalis had the highest values for BP, which varied depending on the origin of the infection. Assessment of BP is a key diagnostic tool that enables us to better understand Candida infections.}, } @article {pmid27155419, year = {2016}, author = {Luo, G and Xu, G and Gao, J and Tan, H}, title = {Effect of dissolved oxygen on nitrate removal using polycaprolactone as an organic carbon source and biofilm carrier in fixed-film denitrifying reactors.}, journal = {Journal of environmental sciences (China)}, volume = {43}, number = {}, pages = {147-152}, doi = {10.1016/j.jes.2015.10.022}, pmid = {27155419}, issn = {1001-0742}, mesh = {Biofilms ; Bioreactors/*microbiology ; Denitrification ; Nitrates/*analysis ; Nitrogen Cycle ; *Oxygen ; Polyesters ; Water Pollutants, Chemical/*analysis ; }, abstract = {Nitrate-nitrogen (NO3(-)-N) always accumulates in commercial recirculating aquaculture systems (RASs) with aerobic nitrification units. The ability to reduce NO3(-)-N consistently and confidently could help RASs to become more sustainable. The rich dissolved oxygen (DO) content and sensitive organisms stocked in RASs increase the difficulty of denitrifying technology. A denitrifying process using biologically degradable polymers as an organic carbon source and biofilm carrier was proposed because of its space-efficient nature and strong ability to remove NO3(-)-N from RASs. The effect of dissolved oxygen (DO) levels on heterotrophic denitrification in fixed-film reactors filled with polycaprolactone (PCL) was explored in the current experiment. DO conditions in the influent of the denitrifying reactors were set up as follows: the anoxic treatment group (Group A, average DO concentration of 0.28±0.05mg/L), the low-oxygen treatment DO group (Group B, average DO concentration of 2.50±0.24mg/L) and the aerated treatment group (Group C, average DO concentration of 5.63±0.57mg/L). Feeding with 200mg/L of NO3(-)-N, the NO3(-)-N removal rates were 1.53, 1.60 and 1.42kg/m(3) PCL/day in Groups A, B and C, respectively. No significant difference in NO3(-)-N removal rates was observed among the three treatments. It was concluded that the inhibitory effects of DO concentrations lower than 6mg/L on heterotrophic denitrification in the fixed-film reactors filled with PCL can be mitigated.}, } @article {pmid27154750, year = {2016}, author = {Siala, W and Van Bambeke, F and Taresco, V and Piozzi, A and Francolini, I}, title = {Synergistic activity between an antimicrobial polyacrylamide and daptomycin versus Staphylococcus aureus biofilm.}, journal = {Pathogens and disease}, volume = {74}, number = {5}, pages = {}, doi = {10.1093/femspd/ftw042}, pmid = {27154750}, issn = {2049-632X}, mesh = {Acrylic Resins/chemistry/*pharmacology ; Anti-Infective Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Daptomycin/chemistry/*pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Bacterial ; Drug Synergism ; Humans ; Microbial Sensitivity Tests ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; }, abstract = {Antibiotic resistance of bacteria growing in biofilms compared to their planktonic counterparts enhances the difficulty to eradicate biofilm-associated infections. In the last decade, combination antibiotic therapy has emerged as an attractive strategy for treating biofilm infections, even if in most of tolerant biofilms the optimal combinations are still unknown. In this study, an antimicrobial cationic polyacrylamide was used in combination with daptomycin or moxifloxacin against mature biofilms of Staphylococcus aureus clinical isolates to examine a possible improvement of the antibiofilm activity of the two antibiotics. The polymer did not have an effect on moxifloxacin but significantly increased the antibiofilm efficacy of daptomycin. These findings are presumably related to the different mechanism of action of the two drugs. In summary, our data highlighted the ability of polycations to increase daptomycin antibiofilm activity providing a potential strategy to eradicate biofilms in industrial or medical settings.}, } @article {pmid27150962, year = {2016}, author = {Yuyama, KT and Abraham, WR}, title = {cis-2-Alkenoic Acids as Promising Drugs for the Control of Biofilm Infections.}, journal = {Medicinal chemistry (Shariqah (United Arab Emirates))}, volume = {13}, number = {1}, pages = {3-12}, doi = {10.2174/1573406412666160506151032}, pmid = {27150962}, issn = {1875-6638}, mesh = {Animals ; Biofilms/*drug effects ; Fatty Acids, Monounsaturated/chemistry/*pharmacology ; Humans ; Pseudomonas Infections/*drug therapy/metabolism ; Pseudomonas aeruginosa/*drug effects/metabolism ; }, abstract = {BACKGROUND: Microbes attach to surfaces and form biofilms where they are difficult to eradicate. Here they are embedded in a complex matrix of polymers and are much less sensitive against antibiotics or the immune system.

OBJECTIVE: This is a growing problem, especially for implants; hence, novel approaches are urgently needed to control biofilm infections.

METHODS: Many of these approaches interfere with the communication between the microbial cells required for biofilm formation and maintenance, a process known as quorum sensing. But microbes have also several mechanisms to disperse their own biofilms if conditions become unfavourable.

RESULTS: Recently, it has been found that the pathogen Pseudomonas aeruginosa disperses its mature biofilms using cis-2-decenoic acid. This fatty acid belongs to a group of cis-2-alkenoic acids which are known from several bacteria and are also triggering the communication between different species. In this review the biosynthesis of these compounds, their signal transduction and their role in species-species communication are presented. Examples are discussed where cis-2-alkenoic acids have been used to eradicate biofilms and enhance the sensitivity of pathogens against antibiotics, either alone or in combination with antibiotics.

CONCLUSION: This presents an interesting approach for the control of biofilm infections but it is still in its infancy and a much broader characterization of the effects of cis-2-alkenoic acids are needed before moving to any medical application.}, } @article {pmid27150551, year = {2016}, author = {Güldas, HE and Kececi, AD and Cetin, ES and Ozturk, T and Kaya, BÜ}, title = {Evaluation of antimicrobial efficacy of cetrimide and Glycyrrhiza glabra L. extract against Enterococcus faecalis biofilm grown on dentin discs in comparison with NaOCl.}, journal = {Dental materials journal}, volume = {35}, number = {5}, pages = {721-727}, doi = {10.4012/dmj.2014-338}, pmid = {27150551}, issn = {1881-1361}, mesh = {Anti-Infective Agents ; *Biofilms ; *Cetrimonium Compounds ; Dentin ; *Enterococcus faecalis ; Glycyrrhiza ; }, abstract = {This study aimed to determine the antimicrobial efficacy of NaOCl, cetrimide, and Glycyrrhiza glabra L. extract against Enterococcus faecalis biofilms on dentine discs. Broth microdilution method was used to determine minimal bactericidal concentrations (MBCs) of the agents. A biofilm susceptibility assay was performed using E. faecalis biofilms grown on dentine discs. Minimal bactericidal concentrations (MBCs) of NaOCl (0.5%), cetrimide (0.015%), and G. glabra L. extract (0.25%) were applied for 1, 3, and 5 min, and the mean viable cell counts were recorded and statistically analyzed. There was no significant difference between cetrimide and NaOCl at 1 min (p>0.05). NaOCl was the most effective agent at 3 and 5 min (p<0.05) while G. glabra L. extract was the least (p<0.05). The MBCs of NaOCl, cetrimide, and G. glabra that eliminated the planktonic E. faecalis did not eradicate the biofilms grown on dentin discs.}, } @article {pmid27150429, year = {2016}, author = {Junka, AF and Szymczyk, P and Secewicz, A and Pawlak, A and Smutnicka, D and Ziółkowski, G and Bartoszewicz, M and Chlebus, E}, title = {The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.}, journal = {Acta of bioengineering and biomechanics}, volume = {18}, number = {1}, pages = {115-120}, pmid = {27150429}, issn = {1509-409X}, mesh = {Biofilms/*drug effects/*growth & development ; Colony Count, Microbial ; Fluorine/analysis ; *Lasers ; Materials Testing/*methods ; Nitrogen/analysis ; Pseudomonas aeruginosa/drug effects/*physiology/ultrastructure ; Titanium/*pharmacology ; }, abstract = {In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds (p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements.}, } @article {pmid27149069, year = {2016}, author = {Klinger-Strobel, M and Suesse, H and Fischer, D and Pletz, MW and Makarewicz, O}, title = {A Novel Computerized Cell Count Algorithm for Biofilm Analysis.}, journal = {PloS one}, volume = {11}, number = {5}, pages = {e0154937}, pmid = {27149069}, issn = {1932-6203}, mesh = {Algorithms ; Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/growth & development ; Biofilms/drug effects/*growth & development ; Cell Count/*methods ; Colistin/pharmacology ; Computer Simulation ; Microbial Sensitivity Tests/methods ; Plankton/drug effects/growth & development ; }, abstract = {Biofilms are the preferred sessile and matrix-embedded life form of most microorganisms on surfaces. In the medical field, biofilms are a frequent cause of treatment failure because they protect the bacteria from antibiotics and immune cells. Antibiotics are selected according to the minimal inhibitory concentration (MIC) based on the planktonic form of bacteria. Determination of the minimal biofilm eradicating concentration (MBEC), which can be up to 1,000-fold greater than the MIC, is not currently conducted as routine diagnostic testing, primarily because of the methodical hurdles of available biofilm assessing protocols that are time- and cost-consuming. Comparative analysis of biofilms is also limited as most quantitative methods such as crystal violet staining are indirect and highly imprecise. In this paper, we present a novel algorithm for assessing biofilm resistance to antibiotics that overcomes several of the limitations of alternative methods. This algorithm aims for a computer-based analysis of confocal microscope 3D images of biofilms after live/dead stains providing various biofilm parameters such as numbers of viable and dead cells and their vertical distributions within the biofilm, or biofilm thickness. The performance of this algorithm was evaluated using computer-simulated 2D and 3D images of coccal and rodent cells varying different parameters such as cell density, shading or cell size. Finally, genuine biofilms that were untreated or treated with nitroxoline or colistin were analyzed and the results were compared with quantitative microbiological standard methods. This novel algorithm allows a direct, fast and reproducible analysis of biofilms after live/dead staining. It performed well in biofilms of moderate cell densities in a 2D set-up however the 3D analysis remains still imperfect and difficult to evaluate. Nevertheless, this is a first try to develop an easy but conclusive tool that eventually might be implemented into routine diagnostics to determine the MBEC and to improve outcomes of patients with biofilm-associated infections.}, } @article {pmid27148715, year = {2016}, author = {Maderova, Z and Horska, K and Kim, SR and Lee, CH and Pospiskova, K and Safarikova, M and Safarik, I}, title = {Decrease of Pseudomonas aeruginosa biofilm formation by food waste materials.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {9}, pages = {2143-2149}, doi = {10.2166/wst.2016.058}, pmid = {27148715}, issn = {0273-1223}, mesh = {Biocompatible Materials ; Biofilms/*growth & development ; *Food ; Magnetics ; Pseudomonas aeruginosa/*physiology ; Refuse Disposal/methods ; *Solid Waste ; }, abstract = {The formation of bacterial biofilm on various surfaces has significant negative economic effects. The aim of this study was to find a simple procedure to decrease the Pseudomonas aeruginosa biofilm formation in a water environment by using different food waste biological materials as signal molecule adsorbents. The selected biomaterials did not reduce the cell growth but affected biofilm formation. Promising biomaterials were magnetically modified in order to simplify manipulation and facilitate their magnetic separation. The best biocomposite, magnetically modified spent grain, exhibited substantial adsorption of signal molecules and decreased the biofilm formation. These results suggest that selected food waste materials and their magnetically responsive derivatives could be applied to solve biofilm problems in water environment.}, } @article {pmid27148706, year = {2016}, author = {Hu, X and Chen, K and Lai, X and Ji, S and Kaiser, K}, title = {Effects of Fe(III) on biofilm and its extracellular polymeric substances (EPS) in fixed bed biofilm reactors.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {9}, pages = {2060-2066}, doi = {10.2166/wst.2016.042}, pmid = {27148706}, issn = {0273-1223}, mesh = {Bacteria/*metabolism ; Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bioreactors ; Ferric Compounds/*pharmacology ; Iron/chemistry ; Molecular Weight ; Photoelectron Spectroscopy ; Polymers/chemistry ; Polysaccharides ; Proteins ; Spectroscopy, Fourier Transform Infrared ; Waste Disposal, Fluid ; Wastewater ; }, abstract = {The effects of Fe(III) on the biofilm mass and activity, the biofilm micromorphology as well as the composition and functional groups characteristics of extracellular polymeric substances (EPS) in biofilm were investigated in laboratory-scale fixed bed biofilm reactors. The results showed that 2 mg/L of Fe(III) promoted the biofilm mass and improved the biofilm activity, but 16 mg/L of Fe(III) adversely affected biofilm development. Scanning electron microscopy (SEM) study indicated a high concentration (16 mg/L) of Fe(III) led to significant reduction of the filaments, great promotion of the EPS secretion in biofilm. The result of the EPS composition suggested 2 mg/L of Fe(III) increased soluble EPS and loosely bound EPS which contributed to the microbial aggregation, while 16 mg/L of Fe(III) promoted tightly bound EPS production unfavourable for substrate mass transfer. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis demonstrated that Fe(III) exerted a significant influence on the -CONH- groups of proteins and the C-O groups of polysaccharides in EPS. This study reveals that Fe(III) influences biofilm development and activity not only by directly impacting the microbial physiology but by indirectly affecting the EPS constituents, and it helps to provide theoretical guidance for iron ion containing wastewater treatment.}, } @article {pmid27149651, year = {2016}, author = {Zhao, A and Zhu, J and Ye, X and Ge, Y and Li, J}, title = {Inhibition of biofilm development and spoilage potential of Shewanella baltica by quorum sensing signal in cell-free supernatant from Pseudomonas fluorescens.}, journal = {International journal of food microbiology}, volume = {230}, number = {}, pages = {73-80}, doi = {10.1016/j.ijfoodmicro.2016.04.015}, pmid = {27149651}, issn = {1879-3460}, mesh = {Animals ; Biofilms/*growth & development ; Cell-Free System/microbiology ; Diketopiperazines/*metabolism ; Fishes/microbiology ; Food Microbiology ; Foodborne Diseases/microbiology ; Homoserine/*analogs & derivatives/metabolism ; Lactones/*metabolism ; Methylamines/metabolism ; Pseudomonas fluorescens/*metabolism ; Quorum Sensing/*physiology ; Seafood/microbiology ; Shewanella/*growth & development ; Signal Transduction ; }, abstract = {The objective of this study was to in vitro evaluate the effect of a cell-free supernatant (CFS) containing quorum sensing (QS) signal of Pseudomonas fluorescens on the growth, biofilm development and spoilage potential of Shewanella baltica, and preliminarily assess the interactive influences of various chemically synthesized autoinducers on spoilage phenotypes of S. baltica. PF01 strain isolated from spoiled Pseudosciaen crocea was identified P. fluorescens. The addition of 25% and 50% CFS to S. baltica culture had no effect on the growth rate during the lag and exponential phase, however, caused cell decline during the stationary phase. The presence of CFS from P. fluorescens significantly inhibited biofilm development, and greatly decreased the production of trimethylamine (TMA) and biogenic amino in S. baltica. Various signal molecules of QS in the CFS of P. fluorescens culture were detected, including seven N-acyl-l-homoserine lactones (AHLs), autoinducer-2 (AI-2) and two diketopiperazines (DKPs). Exogenous supplement of synthesized seven AHLs containing in the CFS decreased biofilm formation and TMA production in S. baltica, while exposure to exogenous cyclo-(l-Pro-l-Leu) was showed to promote spoilage potential, which revealed that S. baltica also sense the two QS molecules. Furthermore, the stimulating effect of cyclo-(l-Pro-l-Leu) was affected when AHL was simultaneously added, suggesting that the inhibitory activity of spoilage phenotypes in S. baltica might be attributed to a competitive effect of these QS compounds in the CFS of P. fluorescens. The present studies provide a good basis for future research on the role of QS in the regulation of spoilage microbial flora.}, } @article {pmid27149574, year = {2016}, author = {Walker, TJ and Toriumi, DM}, title = {Analysis of Facial Implants for Bacterial Biofilm Formation Using Scanning Electron Microscopy.}, journal = {JAMA facial plastic surgery}, volume = {18}, number = {4}, pages = {299-304}, doi = {10.1001/jamafacial.2016.0279}, pmid = {27149574}, issn = {2168-6092}, mesh = {Adult ; *Biofilms ; Device Removal ; Face/*surgery ; Female ; Humans ; Male ; Microscopy, Electron, Scanning ; Polyethylene ; Prostheses and Implants/*microbiology ; Reoperation ; Rhinoplasty/*instrumentation ; Silicones ; Surgical Wound Infection/microbiology ; }, abstract = {IMPORTANCE: Alloplastic implants are widely used in facial plastic surgery, both in rhinoplasty and nonrhinoplasty procedures. Implant infection and extrusion are significant concerns of such implants after placement. Bacterial biofilms have been previously implicated in chronic wound infections, particularly in the presence of foreign bodies, such as alloplastic facial implants. Owing to their structural composition, biofilms are resistant to treatment with conventional antibiotics, and implant removal is frequently the only option.

OBJECTIVE: To evaluate explanted alloplastic facial implants for the presence or absence of bacterial biofilm using scanning electron microscopy.

Facial implants explanted by a single surgeon were analyzed for biofilm formation between July 1, 2012, and June 30, 2013. Of 7 facial implants, 4 consisted of silicone, and 3 were porous polyethylene. Six of the 7 were nasal dorsal implants, and 1 silicone implant was removed from the midface. Nonexplanted fresh silicone and porous polyethylene implants were each used as a control.

MAIN OUTCOMES AND MEASURES: Scanning electron microscopy images were analyzed by an electron microscopist masked to the clinical history and implant type. The presence of biofilm formation was graded as none, mild, moderate, or severe.

RESULTS: A total of 7 patients with previously placed alloplastic facial implants at an outside institution underwent revision rhinoplasty and removal of facial implants. All porous polyethylene implants showed biofilm formation to various degrees. Furthermore, all porous polyethylene implants had at least some areas of severe biofilm formation. One of the 3 porous polyethylene implants demonstrated severe biofilm formation on the entire implant, and the other 2 porous polyethylene implants showed areas of mild and severe biofilm formation. The only 2 implants without any evidence of biofilm were silicone implants. Of the other 2 silicone implants, 1 demonstrated no biofilm formation in 1 area and severe biofilm formation in another area, whereas the other had areas of moderate and severe biofilm formation.

CONCLUSIONS AND RELEVANCE: Five of 7 explanted facial implants showed at least some degree of biofilm formation. All implants with rougher surfaces, namely, porous polyethylene implants, demonstrated biofilm formation to a severe degree. Those with smoother surfaces, namely, silicone implants, were the only ones on which biofilm formation was either absent or less severe. Therefore, the suspicion that biofilms can form on facial implants is established through this investigation.

LEVEL OF EVIDENCE: NA.}, } @article {pmid27148178, year = {2016}, author = {Qi, L and Li, H and Zhang, C and Liang, B and Li, J and Wang, L and Du, X and Liu, X and Qiu, S and Song, H}, title = {Relationship between Antibiotic Resistance, Biofilm Formation, and Biofilm-Specific Resistance in Acinetobacter baumannii.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {483}, pmid = {27148178}, issn = {1664-302X}, abstract = {In this study, we aimed to examine the relationships between antibiotic resistance, biofilm formation, and biofilm-specific resistance in clinical isolates of Acinetobacter baumannii. The tested 272 isolates were collected from several hospitals in China during 2010-2013. Biofilm-forming capacities were evaluated using the crystal violet staining method. Antibiotic resistance/susceptibility profiles to 21 antibiotics were assessed using VITEK 2 system, broth microdilution method or the Kirby-Bauer disc diffusion method. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) to cefotaxime, imipenem, and ciprofloxacin were evaluated using micro dilution assays. Genetic relatedness of the isolates was also analyzed by pulsed-field gel electrophoresis (PFGE) and plasmid profile. Among all the 272 isolates, 31 were multidrug-resistant (MDR), and 166 were extensively drug-resistant (XDR). PFGE typing revealed 167 pattern types and 103 clusters with a similarity of 80%. MDR and XDR isolates built up the main prevalent genotypes. Most of the non-MDR isolates were distributed in a scattered pattern. Additionally, 249 isolates exhibited biofilm formation, among which 63 were stronger biofilm formers than type strain ATCC19606. Population that exhibited more robust biofilm formation likely contained larger proportion of non-MDR isolates. Isolates with higher level of resistance tended to form weaker biofilms. The MBECs for cefotaxime, imipenem, and ciprofloxacin showed a positive correlation with corresponding MICs, while the enhancement in resistance occurred independent of the quantity of biofilm biomass produced. Results from this study imply that biofilm acts as a mechanism for bacteria to get a better survival, especially in isolates with resistance level not high enough. Moreover, even though biofilms formed by isolates with high level of resistance are always weak, they could still provide similar level of protection for the isolates. Further explorations genetically would improve our understanding of these processes and provide novel insights in the therapeutics and prevention against A. baumannii biofilm-related infections.}, } @article {pmid27147073, year = {2016}, author = {de Sousa Farias, SS and Nemezio, MA and Corona, SA and Aires, CP and Borsatto, MC}, title = {Effects of low-level laser therapy combined with toluidine blue on polysaccharides and biofilm of Streptococcus mutans.}, journal = {Lasers in medical science}, volume = {31}, number = {5}, pages = {1011-1016}, pmid = {27147073}, issn = {1435-604X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/analogs & derivatives/pharmacology ; Humans ; Low-Level Light Therapy/*methods ; Microbial Viability/drug effects ; Photochemotherapy/*methods ; Polysaccharides ; Streptococcus mutans/*drug effects ; Tolonium Chloride/*pharmacology ; }, abstract = {The aim of this study was to evaluate the effect of a low-level laser therapy in combination with toluidine blue on polysaccharides and biofilm of Streptococcus mutans. S. mutans biofilms were formed on acrylic resin blocks. These biofilms were exposed eight times/day to 10 % sucrose, and two times/day, they were subjected to one of the following treatments: G1, 0.9 % NaCl as a negative control; G2, 0.12 % chlorhexidine digluconate (CHX) as a positive antibacterial control; and G3 and G4 antimicrobial photodynamic therapy (aPDT) combined with toluidine blue using dosages of 320 and 640 J/cm(2), respectively. The experiment was performed in triplicate. The biofilm formed on each block was collected for determination of the viable bacteria and concentration of insoluble extracellular polysaccharides (IEPS) and intracellular polysaccharides (IPS). CHX and aPDT treatments were able to inhibit bacterial growth in comparison with negative control (p < 0.05). The aPDT treatment reduced the number of viable bacteria formed in the S. mutans biofilm, in a dose-dependent manner (p < 0.05). The concentration of IEPS and IPS in the biofilms formed in presence of aPDT did not differ each other or in comparison to CHX (p > 0.05). The results suggest that low-level laser therapy presents effects on biofilm bacteria viability and in polysaccharides concentration.}, } @article {pmid27146505, year = {2016}, author = {Kekeç, Ö and Gökalsın, B and Karaltı, İ and Kayhan, FE and Sesal, NC}, title = {Effects of Chlorine Stress on Pseudomonas aeruginosa Biofilm and Analysis of Related Gene Expressions.}, journal = {Current microbiology}, volume = {73}, number = {2}, pages = {228-235}, pmid = {27146505}, issn = {1432-0991}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Chlorine/*pharmacology ; Disinfectants/*pharmacology ; Gene Expression Regulation, Bacterial/*drug effects ; Pseudomonas aeruginosa/*drug effects/*genetics/physiology ; Real-Time Polymerase Chain Reaction ; }, abstract = {Chlorine is deployed worldwide to clean waters and prevent water-originated illnesses. However, chlorine has a limited disinfection capacity against biofilms. Microorganisms form biofilms to protect themselves from biological threats such as disinfectant chemicals. Pseudomonas aeruginosa is an opportunistic pathogen and its biofilm form attaches to surfaces, living buried into exopolysaccharides, can be present in all watery environments including tap water and drinking water. This research aimed to study the biofilm trigger mechanism of the opportunistic pathogen P. aeruginosa PAO1 strain, which is known to form biofilm in water supply systems and human body, under chlorine stress levels. In addition to biofilm staining, certain genes that are relevant to the stress condition were selected for gene expression analysis. The bacteria cultures were grown under chlorine stress with concentrations of 0.5, 0.7 and 1 mg/l. Six gene regions were determined related to biofilm and stress response: rpoS, bifA, migA, katB, soxR, and algC. Biofilm formation was analyzed by basic fuchsin staining, and gene expressions were quantified by quantitative real-time PCR. According to the results, highest biofilm production was observed in P. aeruginosa PAO1 wild strain under no stress conditions. Higher biofilm amounts were observed for bacteria under 0.5 and 0.7 mg/l chlorine stress compared to 1 mg/l chlorine stress.}, } @article {pmid27145048, year = {2016}, author = {Dwivedi, R and Nothaft, H and Garber, J and Xin Kin, L and Stahl, M and Flint, A and van Vliet, AH and Stintzi, A and Szymanski, CM}, title = {L-fucose influences chemotaxis and biofilm formation in Campylobacter jejuni.}, journal = {Molecular microbiology}, volume = {101}, number = {4}, pages = {575-589}, doi = {10.1111/mmi.13409}, pmid = {27145048}, issn = {1365-2958}, support = {BB/J004529/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; //Wellcome Trust/United Kingdom ; MOP84224//CIHR/Canada ; }, mesh = {Biofilms/*growth & development ; Campylobacter coli/genetics/metabolism ; Campylobacter jejuni/genetics/metabolism/*physiology ; Carbohydrate Metabolism ; Chemotaxis/physiology ; Fucose/genetics/*metabolism ; Genotype ; }, abstract = {Campylobacter jejuni and Campylobacter coli are zoonotic pathogens once considered asaccharolytic, but are now known to encode pathways for glucose and fucose uptake/metabolism. For C. jejuni, strains with the fuc locus possess a competitive advantage in animal colonization models. We demonstrate that this locus is present in > 50% of genome-sequenced strains and is prevalent in livestock-associated isolates of both species. To better understand how these campylobacters sense nutrient availability, we examined biofilm formation and chemotaxis to fucose. C. jejuni NCTC11168 forms less biofilms in the presence of fucose, although its fucose permease mutant (fucP) shows no change. In a newly developed chemotaxis assay, both wild-type and the fucP mutant are chemotactic towards fucose. C. jejuni 81-176 naturally lacks the fuc locus and is unable to swim towards fucose. Transfer of the NCTC11168 locus into 81-176 activated fucose uptake and chemotaxis. Fucose chemotaxis also correlated with possession of the pathway for C. jejuni RM1221 (fuc+) and 81116 (fuc-). Systematic mutation of the NCTC11168 locus revealed that Cj0485 is necessary for fucose metabolism and chemotaxis. This study suggests that components for fucose chemotaxis are encoded within the fuc locus, but downstream signals only in fuc + strains, are involved in coordinating fucose availability with biofilm development.}, } @article {pmid27144316, year = {2016}, author = {Qayyum, S and Sharma, D and Bisht, D and Khan, AU}, title = {Protein translation machinery holds a key for transition of planktonic cells to biofilm state in Enterococcus faecalis: A proteomic approach.}, journal = {Biochemical and biophysical research communications}, volume = {474}, number = {4}, pages = {652-659}, doi = {10.1016/j.bbrc.2016.04.145}, pmid = {27144316}, issn = {1090-2104}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Enterococcus faecalis/*physiology ; Plankton/physiology ; Protein Translocation Systems/*physiology ; Protein Transport/physiology ; Proteome/*metabolism ; }, abstract = {Enterococcus faecalis is a member of human gut microflora causing nosocomial infection involving biofilm formation. Ethyl methyl sulfonate induced mutants were analysed using crystal violet assay, SEM and CLSM microscopy which confirmed AK-E12 as biofilm efficient and AK-F6 as biofilm deficient mutants. Growth curve pattern revealed AK-E12 was fast growing whereas, AK-F6 was found slow growing mutant. 2D-Electrophorosis and MALDI-TOF analysis revealed over and underexpression of many translation-elongation associated proteins in mutants compared to wild type. Protein translation elongation factor G, translation elongation factor Tu and ribosomal subunit interface proteins were underexpressed and UTP-glucose-1-phosphate uridylyl transferase and cell division protein divIVA were overexpressed in AK-E12 as compared to wild type. In AK-F6, except 10 kDa chaperonin which was over-expressed other selected proteins were found to be suppressed. RT-PCR confirmed proteomic data except for the translation elongation factor G which showed contradictory data of proteome expression in AK-E12. Protein-protein interaction networks were constructed using STRING 10.0 which demonstrated strong connection of translation-elongation proteins with other proteins. Hence, it concludes from the data that translation elongation factors are important in transition of planktonic cells to biofilm cells in Enterococcus faecalis.}, } @article {pmid27143636, year = {2016}, author = {Giacobino, J and Montelli, AC and Barretti, P and Bruder-Nascimento, A and Caramori, JT and Barbosa, L and Bagagli, E}, title = {Fungal peritonitis in patients undergoing peritoneal dialysis (PD) in Brazil: molecular identification, biofilm production and antifungal susceptibility of the agents.}, journal = {Medical mycology}, volume = {54}, number = {7}, pages = {725-732}, doi = {10.1093/mmy/myw030}, pmid = {27143636}, issn = {1460-2709}, mesh = {Adult ; Aged ; Antifungal Agents/*pharmacology ; Biofilms/*growth & development ; Brazil ; Drug Resistance, Fungal ; Female ; Hospitals, University ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Mycoses/*microbiology ; Peritoneal Dialysis/*adverse effects ; Peritonitis/*microbiology ; Retrospective Studies ; Saccharomycetales/classification/*drug effects/isolation & purification/*physiology ; Survival Analysis ; }, abstract = {This paper presents data on fungal peritonitis (FP) in patients undergoing peritoneal dialysis (PD) at the University Hospital of Botucatu Medical School, São Paulo, Brazil. In a total of 422 patients, 30 developed FP, from which the medical records and the fungal isolates of 23 patient cases were studied. All patients presented abdominal pain, cloudy peritoneal effluent, needed hospitalization, had the catheter removed and were treated with fluconazole or fluconazole plus 5-flucitosine; six of them died due to FP. Concerning the agents, it was observed that Candida parapsilosis was the leading species (9/23), followed by Candida albicans (5/23), Candida orthopsilosis (4/23), Candida tropicalis (3/23), Candida guilliermondii (1/23), and Kodamaea ohmeri (1/23). All the isolates were susceptible to amphotericin B, voriconazole and caspofungin whereas C. albicans isolates were susceptible to all antifungals tested. Resistance to fluconazole was observed in three isolates of C. orthopsilosis, and dose-dependent susceptibility to this antifungal was observed in two isolates of C. parapsilosis and in the K. ohmeri isolate. Biofilm production estimates were high or moderate in most isolates, especially in C. albicans species, and low in C. parapsilosis species, with a marked variation among the isolates. This Brazilian study reinforces that FP in PD is caused by a diverse group of yeasts, most prevalently C. parapsilosis sensu stricto species. In addition, they present significant variation in susceptibility to antifungals and biofilm production, thus contributing to the complexity and severity of the clinical features.}, } @article {pmid27141909, year = {2016}, author = {Kim, HS and Cha, E and Kim, Y and Jeon, YH and Olson, BH and Byun, Y and Park, HD}, title = {Raffinose, a plant galactoside, inhibits Pseudomonas aeruginosa biofilm formation via binding to LecA and decreasing cellular cyclic diguanylate levels.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {25318}, pmid = {27141909}, issn = {2045-2322}, mesh = {Adhesins, Bacterial/*metabolism ; Anti-Bacterial Agents/*metabolism ; Biofilms/*drug effects ; Cyclic GMP/*analogs & derivatives/metabolism ; Ginger/chemistry ; Pseudomonas aeruginosa/*drug effects/*physiology ; Raffinose/isolation & purification/*metabolism ; }, abstract = {Biofilm formation on biotic or abiotic surfaces has unwanted consequences in medical, clinical, and industrial settings. Treatments with antibiotics or biocides are often ineffective in eradicating biofilms. Promising alternatives to conventional agents are biofilm-inhibiting compounds regulating biofilm development without toxicity to growth. Here, we screened a biofilm inhibitor, raffinose, derived from ginger. Raffinose, a galactotrisaccharide, showed efficient biofilm inhibition of Pseudomonas aeruginosa without impairing its growth. Raffinose also affected various phenotypes such as colony morphology, matrix formation, and swarming motility. Binding of raffinose to a carbohydrate-binding protein called LecA was the cause of biofilm inhibition and altered phenotypes. Furthermore, raffinose reduced the concentration of the second messenger, cyclic diguanylate (c-di-GMP), by increased activity of a c-di-GMP specific phosphodiesterase. The ability of raffinose to inhibit P. aeruginosa biofilm formation and its molecular mechanism opens new possibilities for pharmacological and industrial applications.}, } @article {pmid27141560, year = {2016}, author = {Putnam, K}, title = {Preventing biofilm formation in flexible endoscopes.}, journal = {AORN journal}, volume = {103}, number = {1}, pages = {P7-8}, doi = {10.1016/s0001-2092(15)01155-2}, pmid = {27141560}, issn = {1878-0369}, mesh = {*Biofilms ; Disinfection/*methods ; Endoscopes/*microbiology ; }, } @article {pmid27141311, year = {2016}, author = {Sapi, E and Balasubramanian, K and Poruri, A and Maghsoudlou, JS and Socarras, KM and Timmaraju, AV and Filush, KR and Gupta, K and Shaikh, S and Theophilus, PA and Luecke, DF and MacDonald, A and Zelger, B}, title = {Evidence of In Vivo Existence of Borrelia Biofilm in Borrelial Lymphocytomas.}, journal = {European journal of microbiology & immunology}, volume = {6}, number = {1}, pages = {9-24}, pmid = {27141311}, issn = {2062-509X}, abstract = {Lyme borreliosis, caused by the spirochete Borrelia burgdorferi sensu lato, has grown into a major public health problem. We recently identified a novel morphological form of B. burgdorferi, called biofilm, a structure that is well known to be highly resistant to antibiotics. However, there is no evidence of the existence of Borrelia biofilm in vivo; therefore, the main goal of this study was to determine the presence of Borrelia biofilm in infected human skin tissues. Archived skin biopsy tissues from borrelial lymphocytomas (BL) were reexamined for the presence of B. burgdorferi sensu lato using Borrelia-specific immunohistochemical staining (IHC), fluorescent in situ hybridization, combined fluorescent in situ hybridization (FISH)-IHC, polymerase chain reaction (PCR), and fluorescent and atomic force microscopy methods. Our morphological and histological analyses showed that significant amounts of Borrelia-positive spirochetes and aggregates exist in the BL tissues. Analyzing structures positive for Borrelia showed that aggregates, but not spirochetes, expressed biofilm markers such as protective layers of different mucopolysaccharides, especially alginate. Atomic force microscopy revealed additional hallmark biofilm features of the Borrelia/alginate-positive aggregates such as inside channels and surface protrusions. In summary, this is the first study that demonstrates the presence of Borrelia biofilm in human infected skin tissues.}, } @article {pmid27135005, year = {2016}, author = {Dabholkar, CS and Shah, M and Kathariya, R and Bajaj, M and Doshi, Y}, title = {Comparative Evaluation of Antimicrobial Activity of Pomegranate-Containing Mouthwash Against Oral-Biofilm Forming Organisms: An Invitro Microbial Study.}, journal = {Journal of clinical and diagnostic research : JCDR}, volume = {10}, number = {3}, pages = {ZC65-9}, pmid = {27135005}, issn = {2249-782X}, abstract = {INTRODUCTION: Pomegranate is considered "A pharmacy unto itself". Hydrolysable tannins called punicalagins which have free scavenging properties are the most abundant polyphenols found in pomegranate-containing mouthwash.

AIM: To evaluate antimicrobial effect of pomegranate- containing mouthwash on oral biofilm-forming bacteria.

MATERIALS AND METHODS: The mouthwashes used were divided into three groups- Group A: Chlorhexidine mouthwash (Hexidine); Group B: Herbal Mouthwash (Hiora) and Group C: Pomegranate-containing Mouthwash (Life-extension). Each mouthwash was diluted to five different concentrations. Reference strains of Streptococcus mutans (S.mutans) (ATCC 25175), Streptococcus salivarius (S.salivarius) (ATCC 7073), and Aggregatibacter actinomycetemcomitans (A.a) (NCTC 9710) were selected as being colonizers in dental biofilm formation. On each culture plate, five wells of 5mm were prepared and mouthwashes with different concentrations were added, followed by incubation in a CO2 jar for 24 hours at 37°C. Inhibition zone diameters were measured using a digital caliper.

RESULTS: Chlorhexidine (0.12%) presented a zone of inhibition between 38.46% to 96.15% for all the three organisms, while Hiora presented zone of inhibition ranging from 33.33% to 69.23% but was resistant at <10 ml of dilution. Pomegranate mouthwash presented a zone of inhibition ranging from 38.48 to 57.69%, but was resistant at <10ml for S.mutans, and <25ml for A.a and S.salivarius. ANOVA test was done to compare the dilution of mouthwashes for a particular organism and Tukey's multiple comparison tests were done to find the exact difference. A significant difference was seen between all the three groups at 50ml and 75 ml of dilution. At 75 ml concentration, a statistical difference was found between Groups B & C and Groups A & B; and at 50 ml between Groups A&C.

CONCLUSION: All the three types of mouthwash exhibit anti-microbial activity against biofilm forming organisms but at varying concentrations. Although Chlorhexidine still continues to be the gold standard, pomegranate-containing or herbal mouthwashes can be easily substituted for long term use, avoiding the side effects of chlorhexidine.}, } @article {pmid27134811, year = {2016}, author = {Willems, HM and Xu, Z and Peters, BM}, title = {Polymicrobial Biofilm Studies: From Basic Science to Biofilm Control.}, journal = {Current oral health reports}, volume = {3}, number = {1}, pages = {36-44}, pmid = {27134811}, issn = {2196-3002}, support = {K22 AI110541/AI/NIAID NIH HHS/United States ; }, abstract = {Microbes rarely exist as single species planktonic forms as they have been commonly studied in the laboratory. Instead, the vast majority exists as part of complex polymicrobial biofilm communities attached to host and environmental surfaces. The oral cavity represents one of the most diverse and well-studied polymicrobial consortia. Despite a burgeoning field of mechanistic biofilm research within the past decades, our understanding of interactions that occur between microbial members within oral biofilms is still limited. Thus, the primary objective of this review is to focus on polymicrobial biofilm formation, microbial interactions and signaling events that mediate oral biofilm development, consequences of oral hygiene on both local and systemic disease, and potential therapeutic strategies to limit oral dysbiosis.}, } @article {pmid27134545, year = {2015}, author = {MubarakAli, D and Arunkumar, J and Pooja, P and Subramanian, G and Thajuddin, N and Alharbi, NS}, title = {Synthesis and characterization of biocompatibility of tenorite nanoparticles and potential property against biofilm formation.}, journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society}, volume = {23}, number = {4}, pages = {421-428}, pmid = {27134545}, issn = {1319-0164}, abstract = {Aim is to assess the anti-biofilm property of tenorite nanoparticles and to study their suitability as a possible coating material for medical implants. Tenorite (CuO) nanoparticles were synthesized by the optimized thermal decomposition method and characterized using TEM, XRD, FTIR and UV-Vis analysis. Their influence on biofilm formation of microbes was studied by growing multi drug resistant bacterial strains in the presence or absence of these nanoparticles at various concentrations. The cytotoxicity of nanoparticles on mammalian cells was studied at the corresponding concentrations. The nanoparticles were found to be uniformly dispersed, spherical shaped and <50 nm in size. They showed various degrees of anti-biofilm property against clinically isolated, biofilm forming multi drug resistant microorganisms such as Staphylococcus aureus, Pseudomonas fluorescens, Burkholderia mallei, Klebsiella pneumoniae, and Escherichia coli. Furthermore, Hep-2 cells showed excellent viability at tenorite nanoparticles concentration toxic to microbial growth. These results indicate that tenorite nanoparticles may be ideal candidates for being utilized as coating on medical implants in general and dental implants in particular.}, } @article {pmid27131840, year = {2016}, author = {Liu, X and Yin, H and Weng, CX and Cai, Y}, title = {Low-Frequency Ultrasound Enhances Antimicrobial Activity of Colistin-Vancomycin Combination against Pan-Resistant Biofilm of Acinetobacter baumannii.}, journal = {Ultrasound in medicine & biology}, volume = {42}, number = {8}, pages = {1968-1975}, doi = {10.1016/j.ultrasmedbio.2016.03.016}, pmid = {27131840}, issn = {1879-291X}, mesh = {Acinetobacter baumannii/*drug effects ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Colistin/*pharmacology ; Drug Combinations ; Microbial Viability/drug effects ; *Ultrasonic Waves ; Vancomycin/*pharmacology ; }, abstract = {Acinetobacter baumannii biofilms in catheters are very difficult to treat. Low-frequency ultrasound (LFU) may improve bactericidal or bacteriostatic activity. However, no previous studies have been reported on its efficacy against pan-resistant biofilms of A. baumannii. This study was designed to investigate whether LFU can enhance the activity of colistin, vancomycin and colistin-vancomycin combinations against pan-resistant biofilms of A. baumannii. The efficacy of colistin combinations was determined using the fractional inhibitory concentration index (FICI). The antibacterial effect was determined from bacteria counts in biofilms and the establishment of 24-h time-kill curves. A significantly synergistic effect was detected between colistin and vancomycin (FICI <0.05). We found that although application of LFU (40 kHz, 600 mW/cm(2), 30 min, duty cycle 1:9) alone or in combination with a single agent failed to significantly reduce bacteria counts in biofilms, it apparently enhanced the antibacterial effectiveness of combinations of these agents. Moreover, higher concentrations of colistin in the combination treatments resulted in a better ultrasound-enhanced antibacterial effect. In 24-h time-kill curves, the combination of colistin (8 μg/mL) plus vancomycin (4 μg/mL) with LFU caused a significant reduction in bacteria counts in biofilms after 8 h and a continuing decline until 24 h. Bacterial counts were reduced by 3.77 log(CFU/mL) by LFU plus combinations, compared with combinations without LFU at 24 h. Our results indicate that LFU in combination with colistin plus vancomycin may be useful in treating pan-resistant A. baumannii infections.}, } @article {pmid27131824, year = {2016}, author = {Ory, J and Bricheux, G and Togola, A and Bonnet, JL and Donnadieu-Bernard, F and Nakusi, L and Forestier, C and Traore, O}, title = {Ciprofloxacin residue and antibiotic-resistant biofilm bacteria in hospital effluent.}, journal = {Environmental pollution (Barking, Essex : 1987)}, volume = {214}, number = {}, pages = {635-645}, doi = {10.1016/j.envpol.2016.04.033}, pmid = {27131824}, issn = {1873-6424}, mesh = {Anti-Bacterial Agents/*analysis/pharmacology ; Bacteria/drug effects/genetics/*growth & development ; *Biofilms ; Ciprofloxacin/*analysis/pharmacology ; *Drug Resistance, Bacterial/genetics ; France ; Genes, Bacterial ; *Hospitals ; Humans ; Plasmids ; *Wastewater/chemistry/microbiology ; }, abstract = {Discharge of antimicrobial residues and resistant bacteria in hospital effluents is supposed to have strong impacts on the spread of antibiotic resistant bacteria in the environment. This study aimed to characterize the effluents of the Gabriel Montpied teaching hospital, Clermont-Ferrand, France, by simultaneously measuring the concentration of ciprofloxacin and of biological indicators resistant to this molecule in biofilms formed in the hospital effluent and by comparing these data to ciprofloxacin consumption and resistant bacterial isolates of the hospital. Determination of the measured environmental concentration of ciprofloxacin by spot sampling and polar organic chemical integrative (POCIS) sampling over 2 weeks, and comparison with predicted environmental concentrations produced a hazard quotient >1, indicating a potential ecotoxicological risk. A negative impact was also observed with whole hospital effluent samples using the Tetrahymena pyriformis biological model. During the same period, biofilms were formed within the hospital effluent, and analysis of ciprofloxacin-resistant isolates indicated that Gamma-Proteobacteria were numerous, predominantly Aeromonadaceae (69.56%) and Enterobacteriaceae (22.61%). Among the 115 isolates collected, plasmid-mediated fluoroquinolone-resistant genes were detected, with mostly aac(6')-lb-cr and qnrS. In addition, 60% of the isolates were resistant to up to six antibiotics, including molecules mostly used in the hospital (aminosides and third-generation cephalosporins). In parallel, 1247 bacteria isolated from hospitalized patients and resistant to at least one of the fluoroquinolones were collected. Only 5 of the 14 species identified in the effluent biofilm were also found in the clinical isolates, but PFGE typing of the Gram-negative isolates found in both compartments showed there was no clonality among the strains. Altogether, these data confirm the role of hospital loads as sources of pollution for wastewater and question the role of environmental biofilms communities as efficient shelters for hospital-released resistance genes.}, } @article {pmid27131496, year = {2016}, author = {Sim, CP and Dashper, SG and Reynolds, EC}, title = {Oral microbial biofilm models and their application to the testing of anticariogenic agents.}, journal = {Journal of dentistry}, volume = {50}, number = {}, pages = {1-11}, doi = {10.1016/j.jdent.2016.04.010}, pmid = {27131496}, issn = {1879-176X}, mesh = {Bacteria ; *Biofilms ; Dental Caries ; Dental Enamel ; Dentin ; }, abstract = {OBJECTIVES: This review paper evaluates the use of in vitro biofilm models for the testing of anticariogenic agents.

DATA: Caries is a biofilm-mediated oral disease and in vitro biofilm models have been widely utilised to assess how anticariogenic or antimicrobial agents affect the de/remineralisation process of caries. The use of enamel or dentine substrata has enabled the assessment of the relationship between bacterial activity and caries lesion initiation and progression and how this relationship could be affected by the agent under study.

SOURCES: Only papers published in the English literature were reviewed.

STUDY SELECTION: Both 'open' and 'closed' biofilm systems utilising either single or multiple-species as defined or undefined inocula are analysed.

CONCLUSIONS: There is a wide variety of in vitro biofilm models used in the assessment of anticariogenic agents. A reproducible model that mimics the shear forces present in the oral environment, and uses a defined multiple-species inocula on tooth substrates can provide valuable insight into the effectiveness of these agents.

CLINICAL RELEVANCE: Biofilm models are important tools for the testing of the mechanism of action and efficacy of novel anticariogenic agents. Results from these experiments help facilitate the design of randomised, controlled clinical trials for testing of efficacy of the agents to provide essential scientific evidence for their clinical use.}, } @article {pmid27131305, year = {2016}, author = {Begum, SS and Radha, KV}, title = {Comparative Kinetic Studies and Performance Evaluation of Biofilm and Biomass Characteristics of Pseudomonas fluorescens in Degrading Synthetic Phenolic Effluent in Inverse Fluidized Bed Biofilm Reactor.}, journal = {Water environment research : a research publication of the Water Environment Federation}, volume = {88}, number = {5}, pages = {415-424}, doi = {10.2175/106143016X14504669768417}, pmid = {27131305}, issn = {1061-4303}, mesh = {Biodegradation, Environmental ; *Biofilms ; Biomass ; Bioreactors ; Kinetics ; Phenols/*metabolism ; Pseudomonas fluorescens/growth & development/*physiology ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/*metabolism ; }, abstract = {The bioremediation potential of Pseudomonas fluorescens was studied in an Inverse Fluidized Bed Biofilm Reactor under batch recirculation conditions using synthetic phenolic effluent of various concentrations (400, 600, 800, 1000 and 1200 mg/l). The performance of the reactor was investigated and the characteristics of biomass and biofilm were determined by evaluating biofilm dry density and thickness, bioparticle density, suspended and attached biomass concentration, chemical oxygen demand and phenol removal efficiency. Biodegradation kinetics had been studied for suspended biomass culture and biofilm systems with respect to its specific growth and substrate consumption rates. Suspended biomass followed substrate inhibition kinetics and the experimental data fitted well with the Haldane model. The degradation kinetic behavior of biofilm revealed that a well adapted biofilm system with effective control of biofilm thickness in an inverse fluidized bed biofilm reactor overcomes substrate inhibition effects by tolerating higher phenol concentration and fitted well to the Monod model.}, } @article {pmid27130477, year = {2016}, author = {Velez Perez, AL and Schmidt-Malan, SM and Kohner, PC and Karau, MJ and Greenwood-Quaintance, KE and Patel, R}, title = {In vitro activity of ceftolozane/tazobactam against clinical isolates of Pseudomonas aeruginosa in the planktonic and biofilm states.}, journal = {Diagnostic microbiology and infectious disease}, volume = {85}, number = {3}, pages = {356-359}, doi = {10.1016/j.diagmicrobio.2016.02.014}, pmid = {27130477}, issn = {1879-0070}, mesh = {Anti-Infective Agents, Urinary/*pharmacology ; Biofilms/*drug effects/growth & development ; Cephalosporins/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Penicillanic Acid/*analogs & derivatives/pharmacology ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/isolation & purification/*physiology ; Tazobactam ; beta-Lactamase Inhibitors/*pharmacology ; }, abstract = {Pseudomonas aeruginosa causes a variety of life-threatening infections, some of which are associated with planktonic and others with biofilm states. Herein, we tested the combination of the novel cephalosporin, ceftolozane, with the β-lactamase inhibitor, tazobactam, against planktonic and biofilm forms of 54 clinical isolates of P. aeruginosa, using cefepime as a comparator. MIC values were determined following Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum biofilm inhibitory concentration (MBIC) values were determined using biofilm-laden pegged lids incubated in antimicrobial challenge plates containing varying concentrations of ceftolozane/tazobactam. Pegged lids were then incubated in growth recovery plates containing cation-adjusted Mueller-Hinton broth to determine the minimum biofilm bactericidal concentration (MBBC). Ceftolozane/tazobactam was highly active against planktonic P. aeruginosa, with all 54 isolates studied testing susceptible (MIC ≤4/4μg/mL). On the other hand, 51/54 biofilm P. aeruginosa had MBICs ≥16/4μg/mL, and all 54 isolates had MBBCs >32μg/mL. Of the 54 isolates, 45 (83.3%) tested susceptible to cefepime, with the MIC50/MIC90 being 4/16μg/mL, respectively, and the MBIC90 and MBBC90 both being >256μg/mL. Although ceftolozane/tazobactam is a promising antimicrobial agent for the treatment of P. aeruginosa infections, it is not highly active against P. aeruginosa biofilms.}, } @article {pmid27129224, year = {2016}, author = {Van Acker, H and Coenye, T}, title = {The Role of Efflux and Physiological Adaptation in Biofilm Tolerance and Resistance.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {24}, pages = {12565-12572}, pmid = {27129224}, issn = {1083-351X}, mesh = {Adaptation, Physiological/*drug effects ; Anti-Infective Agents/metabolism/*pharmacology ; Biofilms/*drug effects/growth & development ; Biological Transport ; Drug Resistance, Bacterial/*drug effects ; Drug Tolerance/physiology ; Humans ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Models, Biological ; }, abstract = {Microbial biofilms demonstrate a decreased susceptibility to antimicrobial agents. Various mechanisms have been proposed to be involved in this recalcitrance. We focus on two of these factors. Firstly, the ability of sessile cells to actively mediate efflux of antimicrobial compounds has a profound impact on resistance and tolerance, and several studies point to the existence of biofilm-specific efflux systems. Secondly, biofilm-specific stress responses have a marked influence on cellular physiology, and contribute to the occurrence of persister cells. We provide an overview of the data that demonstrate that both processes are important for survival following exposure to antimicrobial agents.}, } @article {pmid27129223, year = {2016}, author = {Kavanaugh, JS and Horswill, AR}, title = {Impact of Environmental Cues on Staphylococcal Quorum Sensing and Biofilm Development.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {24}, pages = {12556-12564}, pmid = {27129223}, issn = {1083-351X}, support = {I01 BX002711/BX/BLRD VA/United States ; P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; *Environment ; Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions ; Humans ; Hydrogen-Ion Concentration ; Models, Genetic ; Quorum Sensing/genetics/*physiology ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/genetics/*physiology ; }, abstract = {Staphylococci are commensal bacteria that colonize the epithelial surfaces of humans and many other mammals. These bacteria can also attach to implanted medical devices and develop surface-associated biofilm communities that resist clearance by host defenses and available chemotherapies. These communities are often associated with persistent staphylococcal infections that place a tremendous burden on the healthcare system. Understanding the regulatory program that controls staphylococcal biofilm development, as well as the environmental conditions that modulate this program, has been a focal point of research in recent years. A central regulator controlling biofilm development is a peptide quorum-sensing system, also called the accessory gene regulator or agr system. In the opportunistic pathogen Staphylococcus aureus, the agr system controls production of exo-toxins and exo-enzymes essential for causing infections, and simultaneously, it modulates the ability of this pathogen to attach to surfaces and develop a biofilm, or to disperse from the biofilm state. In this review, we explore advances on the interconnections between the agr quorum-sensing system and biofilm mechanisms, and topics covered include recent findings on how different environmental conditions influence quorum sensing, the impact on biofilm development, and ongoing questions and challenges in the field. As our understanding of the quorum sensing and biofilm interconnection advances, there are growing opportunities to take advantage of this knowledge and develop therapeutic approaches to control staphylococcal infections.}, } @article {pmid27129222, year = {2016}, author = {Sheppard, DC and Howell, PL}, title = {Biofilm Exopolysaccharides of Pathogenic Fungi: Lessons from Bacteria.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {24}, pages = {12529-12537}, pmid = {27129222}, issn = {1083-351X}, mesh = {Antifungal Agents/therapeutic use ; Aspergillus fumigatus/chemistry/drug effects/physiology ; Biofilms/drug effects/*growth & development ; Candida albicans/chemistry/drug effects/physiology ; Fungal Polysaccharides/*metabolism ; Fungi/*chemistry/drug effects/*physiology ; Host-Pathogen Interactions/drug effects ; Humans ; Mycoses/drug therapy/microbiology/physiopathology ; Polysaccharides, Bacterial/metabolism ; }, abstract = {Exopolysaccharides play an important structural and functional role in the development and maintenance of microbial biofilms. Although the majority of research to date has focused on the exopolysaccharide systems of biofilm-forming bacteria, recent studies have demonstrated that medically relevant fungi such as Candida albicans and Aspergillus fumigatus also form biofilms during infection. These fungal biofilms share many similarities with those of bacteria, including the presence of secreted exopolysaccharides as core components of the extracellular matrix. This review will highlight our current understanding of fungal biofilm exopolysaccharides, as well as the parallels that can be drawn with those of their bacterial counterparts.}, } @article {pmid27128436, year = {2016}, author = {Chen, Y and Liu, T and Wang, K and Hou, C and Cai, S and Huang, Y and Du, Z and Huang, H and Kong, J and Chen, Y}, title = {Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro.}, journal = {PloS one}, volume = {11}, number = {4}, pages = {e0153468}, pmid = {27128436}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/administration & dosage ; Bacterial Load ; Biofilms/*drug effects/growth & development ; Drug Synergism ; Flavanones/administration & dosage/*pharmacology ; Genes, Bacterial ; Humans ; In Vitro Techniques ; Quorum Sensing/drug effects/genetics/physiology ; Staphylococcus aureus/*drug effects/genetics/physiology ; Virulence/drug effects ; }, abstract = {Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have synergistic bactericidal effects with antibiotics in vitro. To do this, we used a clinically isolated strain of Staphylococcus aureus 17546 (t037) for biofilm formation. Virulence factors were detected following treatment with baicalein, and the molecular mechanism of its antibiofilm activity was studied. Plate counting, crystal violet staining, and fluorescence microscopy revealed that 32 μg/mL and 64 μg/mL baicalein clearly inhibited 3- and 7-day biofilm formation in vitro. Moreover, colony forming unit count, confocal laser scanning microscopy, and scanning electron microscopy showed that vancomycin (VCM) and baicalein generally enhanced destruction of biofilms, while VCM alone did not. Western blotting and real-time quantitative polymerase chain reaction analyses (RTQ-PCR) confirmed that baicalein treatment reduced staphylococcal enterotoxin A (SEA) and α-hemolysin (hla) levels. Most strikingly, real-time qualitative polymerase chain reaction data demonstrated that 32 μg/mL and 64 μg/mL baicalein downregulated the quorum-sensing system regulators agrA, RNAIII, and sarA, and gene expression of ica, but 16 μg/mL baicalein had no effect. In summary, baicalein inhibited Staphylococcus aureus biofilm formation, destroyed biofilms, increased the permeability of vancomycin, reduced the production of staphylococcal enterotoxin A and α-hemolysin, and inhibited the quorum sensing system. These results support baicalein as a novel drug candidate and an effective treatment strategy for Staphylococcus aureus biofilm-associated infections.}, } @article {pmid27128176, year = {2016}, author = {Vijai Kumar Reddy, T and Jyotsna, A and Prabhavathi Devi, BL and Prasad, RB and Poornachandra, Y and Ganesh Kumar, C}, title = {Design, synthesis and in vitro biological evaluation of short-chain C12-sphinganine and its 1,2,3-triazole analogs as potential antimicrobial and anti-biofilm agents.}, journal = {European journal of medicinal chemistry}, volume = {118}, number = {}, pages = {98-106}, doi = {10.1016/j.ejmech.2016.04.020}, pmid = {27128176}, issn = {1768-3254}, mesh = {Anti-Infective Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Candida albicans/cytology/drug effects/metabolism/physiology ; Chemistry Techniques, Synthetic ; *Drug Design ; Intracellular Space/drug effects/metabolism ; Microbial Sensitivity Tests ; Micrococcus luteus/drug effects/physiology ; Reactive Oxygen Species/metabolism ; Sphingosine/*analogs & derivatives/chemistry ; Staphylococcus aureus/drug effects/physiology ; Triazoles/*chemical synthesis/chemistry/*pharmacology ; }, abstract = {A conceptual synthetic approach of short-chain C12-sphinganine 1 and a small library of its 1,2,3-triazole analogs 2(a-f) has been accomplished using the commercially available and inexpensive 10-undecenoic acid as a starting material. Miyashita's C-2 selective endo mode azidolysis and Huisgen click reaction was employed for the synthesis of the designed analogs. Based on biological evaluation studies of all the synthesized compounds, it was observed that, (2S,3R)-2-(4-(3-hydroxyphenyl)-1H-1,2,3-triazol-1-yl)dodecan-1,3-diol (2b) exhibited promising antimicrobial and antifungal activities. Furthermore, compound 2b was able to inhibit the biofilm formation of Candida albicans MTCC 227, Micrococcus luteus MTCC 2470 and Staphylococcus aureus MTCC 96 with IC50 values of 1.9, 2.1 and 2.9 μg/mL, respectively. Compound 2b increased the levels of reactive oxygen species (ROS) in C. albicans MTCC 227.}, } @article {pmid27127655, year = {2016}, author = {Cai, T and Gallelli, L and Meacci, F and Brugnolli, A and Prosperi, L and Roberta, S and Eccher, C and Mazzoli, S and Lanzafame, P and Caciagli, P and Malossini, G and Bartoletti, R}, title = {The Efficacy of Umbelliferone, Arbutin, and N-Acetylcysteine to Prevent Microbial Colonization and Biofilm Development on Urinary Catheter Surface: Results from a Preliminary Study.}, journal = {Journal of pathogens}, volume = {2016}, number = {}, pages = {1590952}, pmid = {27127655}, issn = {2090-3057}, abstract = {We evaluated, in a preliminary study, the efficacy of umbelliferone, arbutin, and N-acetylcysteine to inhibit biofilm formation on urinary catheter. We used 20 urinary catheters: 5 catheters were incubated with Enterococcus faecalis (control group); 5 catheters were incubated with E. faecalis in presence of umbelliferone (150 mg), arbutin (60 mg), and N-acetylcysteine (150 mg) (group 1); 5 catheters were incubated with E. faecalis in presence of umbelliferone (150 mg), arbutin (60 mg), and N-acetylcysteine (400 mg) (group 2); and 5 catheters were incubated with E. faecalis in presence of umbelliferone (300 mg), arbutin (60 mg), and N-acetylcysteine (150 mg) (group 3). After 72 hours, planktonic microbial growth and microorganisms on catheter surface were assessed. In the control group, we found a planktonic load of ≥10(5) CFU/mL in the inoculation medium and retrieved 3.69 × 10(6) CFU/cm from the sessile cells adherent to the catheter surface. A significantly lower amount in planktonic (p < 0.001) and sessile (p = 0.004) bacterial load was found in group 3, showing <100 CFU/mL and 0.12 × 10(6) CFU/cm in the incubation medium and on the catheter surface, respectively. In groups 1 and 2, 1.67 × 10(6) CFU/cm and 1.77 × 10(6) CFU/cm were found on catheter surface. Our results document that umbelliferone, arbutin, and N-acetylcysteine are able to reduce E. faecalis biofilm development on the surface of urinary catheters.}, } @article {pmid27126502, year = {2016}, author = {Zhao, L and She, Z and Jin, C and Yang, S and Guo, L and Zhao, Y and Gao, M}, title = {Characteristics of extracellular polymeric substances from sludge and biofilm in a simultaneous nitrification and denitrification system under high salinity stress.}, journal = {Bioprocess and biosystems engineering}, volume = {39}, number = {9}, pages = {1375-1389}, doi = {10.1007/s00449-016-1613-x}, pmid = {27126502}, issn = {1615-7605}, mesh = {*Biofilms ; *Denitrification ; *Nitrification ; Polymers/*chemistry ; *Salinity ; Sewage/*chemistry ; Spectroscopy, Fourier Transform Infrared ; *Stress, Physiological ; }, abstract = {The composition and distribution of extracellular polymeric substance (EPS) both from suspended sludge and attached biofilm were investigated in a simultaneous nitrification and denitrification (SND) system with the increase of the salinity from 1.0 to 3.0 %. Fourier-transform infrared (FTIR) spectroscopy and three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy were used to examine proteins (PN), polysaccharides (PS) and humic substances (HS) present in EPS. High total nitrogen removal (above 83.9 %) via SND was obtained in the salinity range of 1.0-2.5 %. Total EPS in the sludge increased from 150.2 to 200.6 mg/gVSS with the increase of salinity from 1.0 to 3.0 %, whereas the corresponding values in the biofilm achieved the maximum of 288.6 mg/g VSS at 2.0 % salinity. Dominant composition of EPS was detected as HS in both sludge and biofilm, having the percentages of 50.6-68.6 and 41.1-69.9 % in total EPS, respectively. Both PN and PS contents in soluble EPS (S-EPS), loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) of sludge and biofilm increased with the increased salinity. The FTIR spectrum and 3D-EEM fluorescence spectroscopy of S-EPS, LB-EPS and TB-EPS in the sludge and biofilm showed the changes of functional groups and conformations of the compositions in EPS with the increase of salinity. The results demonstrated that the characteristics of EPS varied from sludge to biofilm. The obtained results could provide a better understanding of the salinity effect on the EPS characteristics in a SND system.}, } @article {pmid27126412, year = {2016}, author = {Quishida, CC and De Oliveira Mima, EG and Jorge, JH and Vergani, CE and Bagnato, VS and Pavarina, AC}, title = {Photodynamic inactivation of a multispecies biofilm using curcumin and LED light.}, journal = {Lasers in medical science}, volume = {31}, number = {5}, pages = {997-1009}, pmid = {27126412}, issn = {1435-604X}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Candida/*drug effects/physiology ; Curcumin/*pharmacology ; Microscopy, Confocal ; Photochemotherapy/*methods ; Streptococcus mutans/*drug effects/physiology ; }, abstract = {This study evaluated the potential of curcumin-mediated antimicrobial photodynamic inactivation (API) on multispecies biofilms of Candida albicans, Candida glabrata, and Streptococcus mutans of different ages. Acrylic samples (n = 480) were made with standardized rough surfaces and incubated with bacteria and yeast for 24 or 48 h. API was performed with curcumin (80, 100, 120 μM) and LED light. Additional acrylic samples were treated with curcumin or LED light only. Positive control samples received neither light nor curcumin. After API, colony counts were quantified (CFU/mL), cell metabolism was determined by means of XTT assay, and the total biofilm biomass was evaluated using Crystal Violet (CV) staining assay and images were obtained by confocal laser scanning microscopy (CLSM). The data were analyzed by nonparametric two-way ANOVA and post hoc Tukey tests (α < 0.05). For 24-h biofilm, API resulted in statistically significant difference (ρ < 0.001) of viability of C. albicans compared with control (P-L-) for all Cur concentrations. For 48-h biofilm, API resulted in statistically significant difference (ρ < 0.001) compared with control only when Cur at 120 μM was used. API promoted statistically significant difference (ρ ≤ 0.001) in the viability of S. mutans and C. glabrata for all Cur concentrations in the two biofilm ages. In addition, API produced a statistically significant difference (ρ < 0.001) of metabolic activity and of total biomass (ρ < 0.001) of multispecies biofilms compared with control for all Cur concentrations. It can be concluded that both 24- and 48-h biofilms were susceptible to API mediated by Cur; however, 24-h biofilm was more sensitive than the 48-h biofilm.}, } @article {pmid27126187, year = {2016}, author = {Sharifzadeh, A and Khosravi, AR and Ahmadian, S}, title = {Chemical composition and antifungal activity of Satureja hortensis L. essentiall oil against planktonic and biofilm growth of Candida albicans isolates from buccal lesions of HIV(+) individuals.}, journal = {Microbial pathogenesis}, volume = {96}, number = {}, pages = {1-9}, doi = {10.1016/j.micpath.2016.04.014}, pmid = {27126187}, issn = {1096-1208}, mesh = {Antifungal Agents/isolation & purification/*pharmacology ; Biofilms/*drug effects ; Candida albicans/cytology/*drug effects/isolation & purification/physiology ; Candidiasis, Oral/microbiology ; Formazans/analysis ; Gas Chromatography-Mass Spectrometry ; HIV Infections/complications ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Electron, Scanning ; Oils, Volatile/*chemistry/isolation & purification ; Phytochemicals/*analysis/isolation & purification/*pharmacology ; Satureja/*chemistry ; Staining and Labeling ; Tetrazolium Salts/analysis ; }, abstract = {Oral candidiasis is an opportunistic infection of the oral cavity which usually occurs in the immunocompromised individuals. Candida albicans (C. albicans) is the most common species of yeast responsible for oral candidiasis. This study investigated the effects of Satureja hortensis L. essentiall oil (EO) on the planktonic, biofilm formation and mature biofilms of C. albicans isolates from buccal lesions of HIV(+) individuals.

MATERIALS AND METHODS: MTT reduction assay, broth micro-dilution method and scanning electron microscopy (SEM) were employed to determine the effect of mentioned EO on the C. albicans planktonic and biofilm forms. GC-GC/MS was used to detect the major active compounds of EO.

RESULTS: Thymol (45.9%), gamma-terpinen (16.71%), carvacrol (12.81%) and p-cymene (9.61%) were found as the most abundant constituents. MIC values ranged from 250 to 400 μg/ml and MFC values ranged from 350 to 500 μg/ml. All C. albicans isolates formed biofilm on polystyrene plats but the quantity of biofilm mass (optical density) was different for the isolates ranging from 0.850 to 0.559 nm. The mean of biofilm formation by C. albicans isolates was reduced by 87.1 ± 3.7%, 73.6 ± 5.1%, 69.4 ± 5.3% and 67 ± 4.2% at 4800, 3200, 2400 and 1600 μg/ml, respectively. In sub-MIC concentration, SEM analysis revealed loosening of cells, deformity of three dimensional structures of biofilms and shrinkage in cell membranes of sessile cells.

CONCLUSIONS: In conclusion, the substantial anti-fungal activity showed by S. hortensis L. EO suggests exploitation of this oil as potential natural anti-biofilm product to deal with the problem of buccal cavity lesion associated with C. albicans.}, } @article {pmid27125749, year = {2016}, author = {Sanyasi, S and Majhi, RK and Kumar, S and Mishra, M and Ghosh, A and Suar, M and Satyam, PV and Mohapatra, H and Goswami, C and Goswami, L}, title = {Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {24929}, pmid = {27125749}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*metabolism/toxicity ; Bacillus subtilis/*drug effects/physiology ; Biofilms/*drug effects/*growth & development ; Cell Line ; Cell Survival/drug effects ; Cytoskeleton/*drug effects ; Mammals ; Metal Nanoparticles ; Microbial Sensitivity Tests ; Salmonella typhimurium/*drug effects/metabolism ; Silver/*metabolism/toxicity ; }, abstract = {Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20-40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.}, } @article {pmid27123019, year = {2015}, author = {Farhad Mollashahi, N and Bokaeian, M and Farhad Mollashahi, L and Afrougheh, A}, title = {Antifungal Efficacy of Green Tea Extract against Candida Albicans Biofilm on Tooth Substrate.}, journal = {Journal of dentistry (Tehran, Iran)}, volume = {12}, number = {8}, pages = {592-598}, pmid = {27123019}, issn = {1735-2150}, abstract = {OBJECTIVES: Biomechanical preparation and irrigation with antimicrobial solutions are necessary to disinfect the root canal space. This in vitro study aimed to examine the antifungal effect of green tea extract on Candida albicans biofilm formed on tooth substrate.

MATERIALS AND METHODS: Minimum fungicidal concentration (MFC) and minimum inhibitory concentration at which 90% of the isolates were inhibited (MIC90) were studied using green tea extract and sodium hypochlorite with the broth macro-dilution method. Then, anti-candida effects of this extract were tested on tooth substrates of 45 extracted single-canal premolar teeth. After biomechanical cleaning of the root canals, the teeth were sectioned vertically and randomly divided into three groups of 30. All the samples were infected with C. albicans (PTCC 5027) and exposed to the test solutions (sodium hypochlorite, green tea, normal saline) for five, 10 and 15 minutes. Data analyses of the samples were performed using two-way ANOVA.

RESULTS: The average number of microorganisms showed a significant decrease after five, 10 and 15 minutes of exposure to green tea extract and sodium hypochlorite. The average number of C. albicans in green tea extract and sodium hypochlorite groups decreased to 1/3 and 1/2 of the initial values, respectively.

CONCLUSION: Antifungal activity of green tea extract was time-dependent and its inhibitory action did not decrease significantly over time. It is recommended to consider other properties of green tea such as tissue solubility, impact on dentin structure and use as an intracanal medicament or for smear layer removal in the clinical setting.}, } @article {pmid27122202, year = {2016}, author = {Wang, X and Han, J and Li, K and Wang, G and Hao, M}, title = {Multi-layer composite mechanical modeling for the inhomogeneous biofilm mechanical behavior.}, journal = {Journal of bioinformatics and computational biology}, volume = {14}, number = {4}, pages = {1650014}, doi = {10.1142/S0219720016500141}, pmid = {27122202}, issn = {1757-6334}, mesh = {*Biofilms ; Biomechanical Phenomena ; Finite Element Analysis ; Models, Biological ; *Models, Theoretical ; }, abstract = {Experiments showed that bacterial biofilms are heterogeneous, for example, the density, the diffusion coefficient, and mechanical properties of the biofilm are different along the biofilm thickness. In this paper, we establish a multi-layer composite model to describe the biofilm mechanical inhomogeneity based on unified multiple-component cellular automaton (UMCCA) model. By using our model, we develop finite element simulation procedure for biofilm tension experiment. The failure limit and biofilm extension displacement obtained from our model agree well with experimental measurements. This method provides an alternative theory to study the mechanical inhomogeneity in biological materials.}, } @article {pmid27121399, year = {2016}, author = {Ooi, N and Eady, EA and Cove, JH and O'Neill, AJ}, title = {Tert-butyl benzoquinone: mechanism of biofilm eradication and potential for use as a topical antibiofilm agent.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {71}, number = {7}, pages = {1841-1844}, pmid = {27121399}, issn = {1460-2091}, support = {BB/G017158/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/*metabolism ; Benzoquinones/*metabolism ; Biofilms/*drug effects/*growth & development ; Humans ; Microbial Viability/drug effects ; Skin/microbiology ; Staphylococcus aureus/*drug effects/*physiology ; }, abstract = {OBJECTIVES: Tert-butyl benzoquinone (TBBQ) is the oxidation product of tert-butyl hydroquinone (TBHQ), an antimicrobial food additive with >40 years of safe use. TBBQ displays potent activity against Staphylococcus aureus biofilms in vitro. Here, we report on studies to further explore the action of TBBQ on staphylococcal biofilms, and provide a preliminary preclinical assessment of its potential for use as a topical treatment for staphylococcal infections involving a biofilm component.

METHODS: The antibacterial properties of TBBQ were assessed against staphylococci growing in planktonic culture and as biofilms in the Calgary Biofilm Device. Established assays were employed to measure the effects of TBBQ on biofilm structure and bacterial membranes, and to assess resistance potential. A living-skin equivalent was used to evaluate the effects of TBBQ on human skin.

RESULTS: TBBQ eradicated biofilms of S. aureus and other staphylococcal species at concentrations ≤64 mg/L. In contrast to other redox-active agents exhibiting activity against biofilms, TBBQ did not cause substantial destructuring of the biofilm matrix; instead, the antibiofilm activity of the compound was attributed to its ability to kill slow- and non-growing cells via membrane perturbation. TBBQ acted synergistically with gentamicin, did not damage a living-skin equivalent following topical application and exhibited low resistance potential.

CONCLUSIONS: The ability of TBBQ to eradicate biofilms appears to result from its ability to kill bacteria regardless of growth state. Preliminary evaluation suggests that TBBQ represents a promising candidate for development as a topical antibiofilm agent.}, } @article {pmid27120651, year = {2016}, author = {Dlangamandla, C and Dyantyi, SA and Mpentshu, YP and Ntwampe, SK and Basitere, M}, title = {Optimisation of bioflocculant production by a biofilm forming microorganism from poultry slaughterhouse wastewater for use in poultry wastewater treatment.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {8}, pages = {1963-1968}, doi = {10.2166/wst.2016.047}, pmid = {27120651}, issn = {0273-1223}, mesh = {Abattoirs ; Animals ; *Biofilms ; Comamonas/*physiology ; Flocculation ; Industrial Waste ; Kaolin/chemistry ; *Poultry ; Spectroscopy, Fourier Transform Infrared ; Temperature ; Waste Disposal, Fluid/methods ; Wastewater/*chemistry ; Water Pollutants, Chemical ; }, abstract = {Poultry slaughterhouse wastewater contains nutrients that are sufficient for microbial growth; moreover, the wastewater has microorganisms which can be harnessed to perform specific functions. Additionally, these microorganisms can grow either in planktonic (free floating) mode or sessile (attached) mode. This study focused on the optimisation of bioflocculant production by quantifying flocculation activity, determined using kaolin clay (4 g/L), by isolates prevalent in poultry slaughterhouse wastewater. Subsequent to their identification and characterisation, six bacterial strains were initially isolated from the poultry wastewater. Although all the isolated microorganisms produced bioflocculants under different conditions, i.e. pH and temperature, the strain that produced bioflocculants with a higher flocculation activity was isolate BF-3, a Comamonas sp., achieving a flocculation activity of 93.8% at 32.9 °C and pH 6.5. Fourier transform infrared spectroscopy (FTIR) analysis of the bioflocculant of the isolate, showed the presence of hydroxyl, carboxyl, alkane and amine functional groups, an indication that the bioflocculant was a protein constituent.}, } @article {pmid27120629, year = {2016}, author = {Vogl, A and Bischof, F and Wichern, M}, title = {Surface-to-surface biofilm transfer: a quick and reliable startup strategy for mixed culture microbial fuel cells.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {8}, pages = {1769-1776}, doi = {10.2166/wst.2016.003}, pmid = {27120629}, issn = {0273-1223}, mesh = {Bacteria/*metabolism ; *Bacterial Physiological Phenomena ; *Bioelectric Energy Sources ; Biofilms/*growth & development ; Electric Impedance ; }, abstract = {The startup of microbial fuel cells (MFCs) is known to be prone to failure or result in erratic performance impeding the research. The aim of this study was to advise a quick launch strategy for laboratory-scale MFCs that ensures steady operation performance in a short period of time. Different startup strategies were investigated and compared with membraneless single chamber MFCs. A direct surface-to-surface biofilm transfer (BFT) in an operating MFC proved to be the most efficient method. It provided steady power densities of 163 ± 13 mWm(-2) 4 days after inoculation compared to 58 ± 15 mWm(-2) after 30 days following a conventional inoculation approach. The in situ BFT eliminates the need for microbial acclimation during startup and reduces performance fluctuations caused by shifts in microbial biodiversity. Anaerobic pretreatment of the substrate and addition of suspended enzymes from an operating MFC into the new MFC proved to have a beneficial effect on startup and subsequent operation. Polarization methods were applied to characterize the startup phase and the steady state operation in terms of power densities, internal resistance and power overshoot during biofilm maturation. Applying this method a well-working MFC can be multiplied into an array of identically performing MFCs.}, } @article {pmid27119723, year = {2017}, author = {Takahashi, C and Akachi, Y and Ogawa, N and Moriguchi, K and Asaka, T and Tanemura, M and Kawashima, Y and Yamamoto, H}, title = {Morphological study of efficacy of clarithromycin-loaded nanocarriers for treatment of biofilm infection disease.}, journal = {Medical molecular morphology}, volume = {50}, number = {1}, pages = {9-16}, pmid = {27119723}, issn = {1860-1499}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Chitosan/chemistry ; Clarithromycin/*pharmacology ; Colony Count, Microbial ; Drug Carriers/*chemistry ; Lactic Acid/chemistry ; Micelles ; Microbial Viability/drug effects ; Nanoparticles/*chemistry/ultrastructure ; Particle Size ; Polyglycolic Acid/chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer ; Static Electricity ; }, abstract = {In this study, we developed a drug delivery system (DDS) using polymeric nanocarriers for the treatment of biofilm infection disease. Clarithromycin (CAM)-encapsulated and chitosan (CS) modified polymeric nanoparticles (NPs) were prepared using a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus[®]) (Sol) and poly-(DL-lactide-co-glycolide), respectively. To understand the availability of the prepared NPs, we made morphological observations of the antibacterial activity derived from the NPs toward the bacterial cells within the biofilm using scanning electron microscopy and transmission electron microscopy measurements. These results revealed different antibacterial activities for the two types of drug carriers. In the case of CAM-encapsulated + CS-modified Sol micelles treatment, NPs can exert their antibacterial activity not only by the surfactant, CAM and CS effects but also by intrusion into the bacterial cells. Thereby, CAM-encapsulated + CS-modified Sol micelles had a higher antibacterial activity. The morphological information is useful to design suitable NPs for the treatment against biofilm infections.}, } @article {pmid27119650, year = {2016}, author = {Madsen, JS and Røder, HL and Russel, J and Sørensen, H and Burmølle, M and Sørensen, SJ}, title = {Coexistence facilitates interspecific biofilm formation in complex microbial communities.}, journal = {Environmental microbiology}, volume = {18}, number = {8}, pages = {2565-2574}, doi = {10.1111/1462-2920.13335}, pmid = {27119650}, issn = {1462-2920}, mesh = {Bacteria/classification/*growth & development/*metabolism ; Biofilms/*growth & development ; Coculture Techniques ; Microbial Consortia/*physiology ; Microbial Interactions/*physiology ; Phylogeny ; Plankton/growth & development/microbiology ; }, abstract = {Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However, the underlying role of fundamental ecological factors, specifically coexistence and phylogenetic history, in biofilm formation remains unclear. This study examines how social interactions affect biofilm formation in multi-species co-cultures from five diverse environments. We found prevalence of increased biofilm formation among co-cultured bacteria that have coexisted in their original environment. Conversely, when randomly co-culturing bacteria across these five consortia, we found less biofilm induction and a prevalence of biofilm reduction. Reduction in biofilm formation was even more predominant when co-culturing bacteria from environments where long-term coexistence was unlikely to have occurred. Phylogenetic diversity was not found to be a strong underlying factor but a relation between biofilm induction and phylogenetic history was found. The data indicates that biofilm reduction is typically correlated with an increase in planktonic cell numbers, thus implying a behavioral response rather than mere growth competition. Our findings suggest that an increase in biofilm formation is a common adaptive response to long-term coexistence.}, } @article {pmid27118030, year = {2016}, author = {Hakobyan, S and Rzhepishevska, O and Björn, E and Boily, JF and Ramstedt, M}, title = {Influence of chelation strength and bacterial uptake of gallium salicylidene acylhydrazide on biofilm formation and virulence of Pseudomonas aeruginosa.}, journal = {Journal of inorganic biochemistry}, volume = {160}, number = {}, pages = {24-32}, doi = {10.1016/j.jinorgbio.2016.04.010}, pmid = {27118030}, issn = {1873-3344}, mesh = {ADP Ribose Transferases/*antagonists & inhibitors/biosynthesis/metabolism ; Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Bacterial Toxins/*antagonists & inhibitors/biosynthesis ; Biofilms/drug effects/growth & development ; Biological Transport ; Chelating Agents/chemical synthesis/*pharmacology ; Coordination Complexes/chemical synthesis/*pharmacology ; Gallium/*chemistry ; Hydrazones/chemical synthesis/*pharmacology ; Kinetics ; Protons ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism/pathogenicity ; Virulence ; Virulence Factors/antagonists & inhibitors/biosynthesis ; }, abstract = {Development of antibiotic resistance in bacteria causes major challenges for our society and has prompted a great need for new and alternative treatment methods for infection. One promising approach is to target bacterial virulence using for example salicylidene acylhydrazides (hydrazones). Hydrazones coordinate metal ions such as Fe(III) and Ga(III) through a five-membered and a six-membered chelation ring. One suggested mode of action is via restricting bacterial Fe uptake. Thus, it was hypothesized that the chelating strength of these substances could be used to predict their biological activity on bacterial cells. This was investigated by comparing Ga chelation strength of two hydrazone complexes, as well as bacterial Ga uptake, biofilm formation, and virulence in the form of production and secretion of a toxin (ExoS) by Pseudomonas aeruginosa. Equilibrium constants for deprotonation and Ga(III) binding of the hydrazone N'-(5-chloro-2-hydroxy-3-methylbenzylidene)-2,4-dihydroxybenzhydrazide (ME0329), with anti-virulence effect against P. aeruginosa, were determined and compared to bacterial siderophores and the previously described Ga(III) 2-oxo-2-[N-(2,4,6-trihydroxy-benzylidene)-hydrazino]-acetamide (Ga-ME0163) and Ga-citrate complexes. In comparison with these two complexes, it was shown that the uptake of Ga(III) was higher from the Ga-ME0329 complex. The results further show that the Ga-ME0329 complex reduced ExoS expression and secretion to a higher extent than Ga-citrate, Ga-ME0163 or the non-coordinated hydrazone. However, the effect against biofilm formation by P. aeruginosa, by the ME0329 complex, was similar to Ga-citrate and lower than what has been reported for Ga-ME0163.}, } @article {pmid27117484, year = {2016}, author = {Srivastava, V and Dubey, AK}, title = {Anti-biofilm activity of the metabolites of Streptomyces chrestomyceticus strain ADP4 against Candida albicans.}, journal = {Journal of bioscience and bioengineering}, volume = {122}, number = {4}, pages = {434-440}, doi = {10.1016/j.jbiosc.2016.03.013}, pmid = {27117484}, issn = {1347-4421}, mesh = {Antifungal Agents/chemistry/*metabolism/*pharmacology ; Biofilms/*drug effects ; Candida albicans/cytology/*drug effects/*growth & development/metabolism ; Cell Adhesion/drug effects ; Hyphae/drug effects ; Microbial Sensitivity Tests ; Polystyrenes ; Streptomyces/*chemistry/classification/*metabolism ; }, abstract = {Candida albicans is a commensal but a significant opportunistic pathogen. It forms biofilms, which protect them against anti-Candida compounds. Therefore, an agent capable of disrupting the Candida biofilms will be useful in the treatment of such infections. The metabolites of Streptomyces chrestomyceticus strain ADP4 displayed strong anti-Candida activity, hence were investigated further for their ability to inhibit biofilm. Strong inhibition of biofilms produced by several reference strains of C. albicans was observed with BIC90 values ranging from 4 to 8 μg/mL. The anti-biofilm activity of ADP4 metabolites appeared to involve membrane disruption and leakage of cellular materials. Also, it effectively inhibited Candida cells from adhering to polystyrene surface and inhibited their conversion to the hyphal state, thereby preventing further development of the biofilm by the adherent cells. This is the first such report on the metabolites produced by any strain of S. chrestomyceticus.}, } @article {pmid27116468, year = {2016}, author = {Fagerlund, A and Smith, V and Røhr, ÅK and Lindbäck, T and Parmer, MP and Andersson, KK and Reubsaet, L and Økstad, OA}, title = {Cyclic diguanylate regulation of Bacillus cereus group biofilm formation.}, journal = {Molecular microbiology}, volume = {101}, number = {3}, pages = {471-494}, doi = {10.1111/mmi.13405}, pmid = {27116468}, issn = {1365-2958}, mesh = {Bacillus cereus/genetics/metabolism/*physiology ; Bacillus subtilis/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Cyclic GMP/*analogs & derivatives/biosynthesis/metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Deletion ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; Second Messenger Systems ; }, abstract = {Biofilm formation can be considered a bacterial virulence mechanism. In a range of Gram-negatives, increased levels of the second messenger cyclic diguanylate (c-di-GMP) promotes biofilm formation and reduces motility. Other bacterial processes known to be regulated by c-di-GMP include cell division, differentiation and virulence. Among Gram-positive bacteria, where the function of c-di-GMP signalling is less well characterized, c-di-GMP was reported to regulate swarming motility in Bacillus subtilis while having very limited or no effect on biofilm formation. In contrast, we show that in the Bacillus cereus group c-di-GMP signalling is linked to biofilm formation, and to several other phenotypes important to the lifestyle of these bacteria. The Bacillus thuringiensis 407 genome encodes eleven predicted proteins containing domains (GGDEF/EAL) related to c-di-GMP synthesis or breakdown, ten of which are conserved through the majority of clades of the B. cereus group, including Bacillus anthracis. Several of the genes were shown to affect biofilm formation, motility, enterotoxin synthesis and/or sporulation. Among these, cdgF appeared to encode a master diguanylate cyclase essential for biofilm formation in an oxygenated environment. Only two cdg genes (cdgA, cdgJ) had orthologs in B. subtilis, highlighting differences in c-di-GMP signalling between B. subtilis and B. cereus group bacteria.}, } @article {pmid27115356, year = {2016}, author = {Javanbakht, T and Laurent, S and Stanicki, D and Wilkinson, KJ}, title = {Relating the Surface Properties of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) to Their Bactericidal Effect towards a Biofilm of Streptococcus mutans.}, journal = {PloS one}, volume = {11}, number = {4}, pages = {e0154445}, pmid = {27115356}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/chemical synthesis/*pharmacology ; Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Diffusion ; Ethylenediamines/chemistry ; Ferric Compounds/chemistry/*pharmacology ; Magnetite Nanoparticles/chemistry/*toxicity/ultrastructure ; Plankton/drug effects/growth & development ; Static Electricity ; Streptococcus mutans/*drug effects/physiology ; Structure-Activity Relationship ; Succinates/chemistry ; Surface Properties ; }, abstract = {This study was designed to determine the effects of superparamagnetic iron oxide nanoparticles (SPIONs) on the biological activity of a bacterial biofilm (Streptococcus mutans). Our hypothesis was that the diffusion of the SPIONs into biofilms would depend on their surface properties, which in turn would largely be determined by their surface functionality. Bare, positively charged and negatively charged SPIONs, with hydrodynamic diameters of 14.6 ± 1.4 nm, 20.4 ± 1.3 nm and 21.2 ± 1.6 nm were evaluated. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and electrophoretic mobility (EPM) measurements were used to confirm that carboxylic functional groups predominated on the negatively charged SPIONS, whereas amine functional groups predominated on the positively charged particles. Transmission electron microscopy (TEM) showed the morphology and sizes of SPIONs. Scanning electron microscopy (SEM) and EPM measurements indicated that the surfaces of the SPIONs were covered with biomolecules following their incubation with the biofilm. Bare SPIONs killed bacteria less than the positively charged SPIONs at the highest exposure concentrations, but the toxicity of the bare and positively charged SPIONs was the same for lower SPION concentrations. The positively charged SPIONs were more effective in killing bacteria than the negatively charged ones. Nonetheless, electrophoretic mobilities of all three SPIONs (negative, bare and positively charged) became more negative following incubation with the (negatively-charged) biofilm. Therefore, while the surface charge of SPIONS was important in determining their biological activity, the initial surface charge was not constant in the presence of the biofilm, leading eventually to SPIONS with fairly similar surface charges in situ. The study nonetheless suggests that the surface characteristics of the SPIONS is an important parameter controlling the efficiency of antimicrobial agents. The analysis of the CFU/mL values shows that the SPIONs have the same toxicity on bacteria in solution in comparison with that on the biofilm.}, } @article {pmid27112502, year = {2016}, author = {Chen, X and Liu, Y and Peng, L and Yuan, Z and Ni, BJ}, title = {Model-Based Feasibility Assessment of Membrane Biofilm Reactor to Achieve Simultaneous Ammonium, Dissolved Methane, and Sulfide Removal from Anaerobic Digestion Liquor.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {25114}, pmid = {27112502}, issn = {2045-2322}, mesh = {Aerobiosis ; Ammonium Compounds/*metabolism ; Anaerobiosis ; Biofilms/*growth & development ; Biota ; Membranes/*microbiology ; Methane/*metabolism ; Models, Theoretical ; Oxidation-Reduction ; Oxygen/metabolism ; Sulfides/*metabolism ; Water Purification/*methods ; }, abstract = {In this study, the membrane biofilm reactor (MBfR) is proposed to achieve simultaneous removal of ammonium, dissolved methane, and sulfide from main-stream and side-stream anaerobic digestion liquors. To avoid dissolved methane stripping, oxygen is introduced through gas-permeable membranes, which also from the substratum for the growth of a biofilm likely comprising ammonium oxidizing bacteria (AOB), anaerobic ammonium oxidation (Anammox) bacteria, denitrifying anaerobic methane oxidation (DAMO) microorganisms, aerobic methane oxidizing bacteria (MOB), and sulfur oxidizing bacteria (SOB). A mathematical model is developed and applied to assess the feasibility of such a system and the associated microbial community structure under different operational conditions. The simulation studies demonstrate the feasibility of achieving high-level (>97.0%), simultaneous removal of ammonium, dissolved methane, and sulfide in the MBfRs from both main-stream and side-stream anaerobic digestion liquors through adjusting the influent surface loading (or hydraulic retention time (HRT)) and the oxygen surface loading. The optimal HRT was found to be inversely proportional to the corresponding oxygen surface loading. Under the optimal operational conditions, AOB, DAMO bacteria, MOB, and SOB dominate the biofilm of the main-stream MBfR, while AOB, Anammox bacteria, DAMO bacteria, and SOB coexist in the side-stream MBfR to remove ammonium, dissolved methane, and sulfide simultaneously.}, } @article {pmid27111260, year = {2016}, author = {Kumari, S and Mangwani, N and Das, S}, title = {Synergistic effect of quorum sensing genes in biofilm development and PAHs degradation by a marine bacterium.}, journal = {Bioengineered}, volume = {7}, number = {3}, pages = {205-211}, pmid = {27111260}, issn = {2165-5987}, mesh = {Bacterial Proteins/genetics ; Biofilms/*drug effects ; Polycyclic Aromatic Hydrocarbons ; Pseudomonas aeruginosa/genetics ; Quorum Sensing/*drug effects ; }, abstract = {Quorum sensing (QS) is a prevalently found intercellular signaling system in bacteria. QS system bestows behavioral coordination ability in bacteria at high population density. QS via acylated homoserine lactone (AHL) is extensively conserved in Gram-negative bacteria and plays crucial role in regulating many biological processes. The role of QS genes coding for AHL synthase enzyme (lasI and rhlI) was established in bioremediation of polycyclic aromatic hydrocarbons (PAHs) viz. phenanthrene and pyrene. AHL producing biofilm forming marine bacterium Pseudomonas aeruginosa N6P6 was isolated by selective enrichment on PAHs. AHL production was confirmed using AHL bioreporters and GC-MS analysis. Biofilm development and its architecture was significantly (P < 0.05) affected by alterations in lasI/rhlI expression. The lasI/rhlI gene expression pattern significantly influences biofilm formation and subsequent degradation of PAHs. The integrated density of Pseudomonas aeruginosa N6P6 biofilm was highest for 48 h old biofilm and the PAHs (phenanthrene and pyrene) degradation was also found maximum (85.6 % and 47.56 %) with this biofilm. A significant positive correlation (P < 0.05) was observed between lasI expression and PAHs degradation. The role of QS genes in biofilm formation and degradation of PAHs was validated by blocking the transcription of lasI/rhlI by a QS inhibitor (QSI) tannic acid. Further, application of such QS positive isolates in PAHs contaminated sites could be a promising strategy to improve the PAHs bioremediation.}, } @article {pmid27110973, year = {2016}, author = {Pepi, M and Borra, M and Tamburrino, S and Saggiomo, M and Viola, A and Biffali, E and Balestra, C and Sprovieri, M and Casotti, R}, title = {A Bacillus sp. isolated from sediments of the Sarno River mouth, Gulf of Naples (Italy) produces a biofilm biosorbing Pb(II).}, journal = {The Science of the total environment}, volume = {562}, number = {}, pages = {588-595}, doi = {10.1016/j.scitotenv.2016.04.097}, pmid = {27110973}, issn = {1879-1026}, mesh = {Adsorption ; Bacillus/genetics/*metabolism ; Bacteria ; Biodegradation, Environmental ; Biofilms ; Geologic Sediments/chemistry/microbiology ; Italy ; Lead/*metabolism ; Microscopy, Electron, Scanning ; RNA, Ribosomal, 16S ; Rivers/chemistry/microbiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {A Pb-resistant bacterial strain (named hereinafter Pb15) has been isolated from highly polluted marine sediments at the Sarno River mouth, Italy, using an enrichment culture to which Pb(II) 0.48mmoll(-1) were added. 16S rRNA gene sequencing (Sanger) allowed assignment of the isolate to the genus Bacillus, with Bacillus pumilus as the closest species. The isolate is resistant to Pb(II) with a minimum inhibitory concentration (MIC) of 4.8mmoll(-1) and is also resistant to Cd(II) and Mn(II) with MIC of 2.22mmoll(-1) and 18.20mmoll(-1), respectively. Inductively coupled plasma atomic emission spectrometry (ICP-AES) showed that Pb inoculated in the growth medium is absorbed by the bacterial cells at removal efficiencies of 31.02% and 28.21% in the presence of 0.48mmoll(-1) or 1.20mmoll(-1) Pb(II), respectively. Strain Pb15 forms a brown and compact biofilm when grown in presence of Pb(II). Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS) confirm that the biofilm contains Pb, suggesting an active biosorption of this metal by the bacterial cells, sequestering 14% of inoculated Pb as evidenced by microscopic analyses. Altogether, these observations support evidence that strain Pb15 has potentials for being used in bioremediation of its native polluted sediments, with engineering solutions to be found in order to eliminate the adsorbed Pb before replacement of sediments in situ.}, } @article {pmid27110187, year = {2016}, author = {Horváthová, T and Babik, W and Bauchinger, U}, title = {Biofilm feeding: Microbial colonization of food promotes the growth of a detritivorous arthropod.}, journal = {ZooKeys}, volume = {}, number = {577}, pages = {25-41}, pmid = {27110187}, issn = {1313-2989}, abstract = {Feeding on plant material is common among animals, but how different animals overcome the dietary deficiencies imposed by this feeding strategy is not well understood. Microorganisms are generally considered to play a vital role in the nutritional ecology of plant feeding animals. Commonly microbes living inside animal bodies are considered more important, but recent studies suggest external microbes significantly shape plant-feeding strategies in invertebrates. Here we investigate how external microbes that typically form biofilm on primary plant material affect growth rates in a terrestrial isopod species Porcellio scaber. We experimentally manipulated the amount of biofilm on three different primary diet sources and quantified growth and survival of individuals that fed on food with either a small or large amount of biofilm. In addition, we tested how dietary manipulation shapes the composition of bacterial communities in the gut. The presence of visible biofilm significantly affected the growth of isopods: individuals that fed on the primary diet source with a large amount of biofilm gained more mass than individuals feeding on a diet with marginal biofilm. Diet also significantly affected the bacterial gut community. The primary diet source mainly determined the taxonomic composition of the bacterial community in the isopod gut, whereas the amount of biofilm affected the relative abundance of bacterial taxa. Our study suggests that terrestrial isopods may cope with low-quality plant matter by feeding on biofilm, with decomposition of plant material by organisms outside of the feeding organism (here a terrestrial isopod) probably playing a major role. Future investigations may be directed towards the primary diet source, plant matter, and the secondary diet source, biofilm, and should assess if both components are indeed uptaken in detritivorous species.}, } @article {pmid27110028, year = {2016}, author = {Li, W and Yao, Z and Sun, L and Hu, W and Cao, J and Lin, W and Lin, X}, title = {Proteomics Analysis Reveals a Potential Antibiotic Cocktail Therapy Strategy for Aeromonas hydrophila Infection in Biofilm.}, journal = {Journal of proteome research}, volume = {15}, number = {6}, pages = {1810-1820}, doi = {10.1021/acs.jproteome.5b01127}, pmid = {27110028}, issn = {1535-3907}, mesh = {Aeromonas hydrophila/*drug effects ; Anti-Bacterial Agents/pharmacology/*therapeutic use ; Bacterial Proteins/metabolism ; Biofilms/*drug effects ; Chlortetracycline/pharmacology/therapeutic use ; Drug Resistance, Bacterial ; Drug Therapy, Combination/methods ; Fatty Acids/biosynthesis ; Gram-Negative Bacterial Infections/*drug therapy ; Propionates/metabolism ; Proteomics/*methods ; Triclosan/therapeutic use ; }, abstract = {Antibiotic fitness and acquired resistance are the two critical factors when bacteria respond to antibiotics, and the correlations and mechanisms between these two factors remain largely unknown. In this study, a TMT-labeling-based quantitative proteomics method was used to compare the differential expression of proteins between the fitness and acquired resistance to chlortetracycline in Aeromonas hydrophila biofilm. Bioinformatics analysis showed that translation-related ribosomal proteins, such as 30s ribosome subunits, increased in both factors; fatty acid biosynthesis related proteins, such as FabB, FabD, FabG, AccA, and AccD, increased in biofilm fitness, and some pathways (including propanoate-metabolism-related protein, such as PrpB, AtoB, PflB, AcsA, PrpD, and GabT) displayed decreased abundance in acquired resistance biofilm. The varieties of selected proteins involved in fatty acid biosynthesis and propanoate metabolism were further validated by q-PCR assay or Western blotting. Furthermore, the antibiotic-resistance-function assays showed that fatty-acid biosynthesis should be a protective antibiotics-resistance mechanism and a cocktail of chlortetracycline and triclosan, a fatty-acid-biosynthesis inhibitor, exhibited more efficient antimicrobial capability than did each antibiotic individually on biofilm, specifically on chlortetracycline-sensitive biofilm. We therefore demonstrate that the up-regulation of fatty acid biosynthesis may play an important role in antibiotic resistance and suggest that a cocktail of chlortetracycline and triclosan may be a potential cocktail therapy for pathogenic infections in biofilm.}, } @article {pmid27109928, year = {2016}, author = {Trivedi, A and Mavi, PS and Bhatt, D and Kumar, A}, title = {Thiol reductive stress induces cellulose-anchored biofilm formation in Mycobacterium tuberculosis.}, journal = {Nature communications}, volume = {7}, number = {}, pages = {11392}, pmid = {27109928}, issn = {2041-1723}, mesh = {Adenosine Diphosphate/metabolism ; Adenosine Triphosphate/metabolism ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Cellulose/chemistry/*metabolism ; Dithiothreitol/*pharmacology ; Gene Expression Regulation, Bacterial/drug effects ; Humans ; Mycobacterium tuberculosis/chemistry/*drug effects/genetics/*physiology ; NAD/metabolism ; NADP/metabolism ; }, abstract = {Mycobacterium tuberculosis (Mtb) forms biofilms harbouring antibiotic-tolerant bacilli in vitro, but the factors that induce biofilm formation and the nature of the extracellular material that holds the cells together are poorly understood. Here we show that intracellular thiol reductive stress (TRS) induces formation of Mtb biofilms in vitro, which harbour drug-tolerant but metabolically active bacteria with unchanged levels of ATP/ADP, NAD(+)/NADH and NADP(+)/NADPH. The development of these biofilms requires DNA, RNA and protein synthesis. Transcriptional analysis suggests that Mtb modulates only ∼7% of its genes for survival in biofilms. In addition to proteins, lipids and DNA, the extracellular material in these biofilms is primarily composed of polysaccharides, with cellulose being a key component. Our results contribute to a better understanding of the mechanisms underlying Mtb biofilm formation, although the clinical relevance of Mtb biofilms in human tuberculosis remains unclear.}, } @article {pmid27108548, year = {2016}, author = {Sethupathy, S and Prasath, KG and Ananthi, S and Mahalingam, S and Balan, SY and Pandian, SK}, title = {Proteomic analysis reveals modulation of iron homeostasis and oxidative stress response in Pseudomonas aeruginosa PAO1 by curcumin inhibiting quorum sensing regulated virulence factors and biofilm production.}, journal = {Journal of proteomics}, volume = {145}, number = {}, pages = {112-126}, doi = {10.1016/j.jprot.2016.04.019}, pmid = {27108548}, issn = {1876-7737}, mesh = {Biofilms/drug effects/growth & development ; Curcumin/*pharmacology ; Homeostasis ; Iron/*metabolism ; Oxidative Stress/drug effects ; Proteomics/*methods ; Pseudomonas aeruginosa/*physiology ; Quorum Sensing/drug effects ; Virulence Factors/antagonists & inhibitors/biosynthesis ; }, abstract = {UNLABELLED: The aim of the present study was to evaluate the effect of known quorum sensing inhibitors (QSIs) against reference strain Pseudomonas aeruginosa PAO1 and 32 clinical isolates. Among the evaluated QSIs, curcumin effectively inhibited the production of quorum sensing (QS) regulated virulence factors and biofilm production in the reference strain as well as all the clinical isolates. Hence, we sought to unearth the underlying molecular mechanism responsible for QS inhibition by curcumin. Proteomic, mass spectrometric and gene ontology analysis revealed that the differentially regulated proteins are indeed involved in iron acquisition, iron storage, detoxification of reactive oxygen species and synthesis of metabolic intermediates for virulence factor production. In vitro assays also confirmed the alterations in catalase, superoxide dismutase, pyocyanin and pyoverdine production and sensitivity of PAO1 to H2O2 upon curcumin exposure. All these results suggest that curcumin attenuates the QS and biofilm formation by affecting iron homeostasis and oxidative stress response of PAO1. Furthermore, successive exposure of PAO1 to curcumin for 20 successive passages does not affect the efficacy of curcumin to inhibit virulence factor and biofilm production. Hence, it is hypothesized that curcumin inhibits the virulence factor production and biofilm formation without obviously inciting any selection pressure from PAO1.

BIOLOGICAL SIGNIFICANCE: Most of the well-known QSIs, which are effective against standard strains of P. aeruginosa, are found ineffective against QS regulated virulence determinants of clinical isolates of P. aeruginosa, suggesting the existence of resistance towards QS inhibitors. The non-toxic nature, wide range of pharmacological benefits and the ability to inhibit the QS regulated virulence factors of all the tested clinical isolates of P. aeruginosa in the current study makes curcumin as a potent antagonistic agent against P. aeruginosa. The study on proteomics of P. aeruginosa against curcumin is expected to hold a greater significance in the development of antipseudomonal regimen. The results revealed the ability of curcumin to attenuate the virulence by targeting antioxidant enzymes, iron transport and biosynthesis of metabolic intermediates involved in virulence factors production.}, } @article {pmid27107380, year = {2016}, author = {Kawarai, T and Narisawa, N and Yoneda, S and Tsutsumi, Y and Ishikawa, J and Hoshino, Y and Senpuku, H}, title = {Inhibition of Streptococcus mutans biofilm formation using extracts from Assam tea compared to green tea.}, journal = {Archives of oral biology}, volume = {68}, number = {}, pages = {73-82}, doi = {10.1016/j.archoralbio.2016.04.002}, pmid = {27107380}, issn = {1879-1506}, mesh = {Biofilms/*drug effects/growth & development ; Camellia sinensis/*chemistry ; Catechin/pharmacology ; Dental Caries/microbiology/prevention & control ; Durapatite ; Hexuronic Acids/pharmacology ; Humans ; Pectins/pharmacology ; Plant Extracts/*pharmacology ; Saliva/microbiology ; Streptococcus mutans/*drug effects/*physiology ; Tea/*chemistry ; Toothpastes/chemistry ; }, abstract = {OBJECTIVE: Streptococcus mutans, a gram-positive oral bacterium, has been identified as one of the principal etiological agents of human dental caries. To clarify the nature of the difference anti-biofilm effect against S. mutans between Assam tea from Camellia sinensis var. assamica, partially fermented, and green tea from Camellia sinensis, non-fermented, active agents from the teas were purified.

METHODS: Effects of Assam tea and green tea samples on biofilm were assessed by using the conventional titer plate method and the human saliva-coated hydroxyapatite discs. The purification and identification of inhibitors were performed by using ultrafiltration with centrifugal filter devices and high performance liquid chromatography.

RESULTS: Assam tea has stronger biofilm inhibition activity against S. mutans than green tea. A substance of <10kDa in mass in Assam tea had a high concentration of galloylated catechins and a stronger biofilm inhibiting activity than green tea. In contrast, substances >10kDa in mass from green tea included higher concentrations of polysaccharides composed of galacturonic acid, such as pectin, that enhance biofilm formation.

CONCLUSIONS: The higher concentrations of galloylated catechins in Assam tea may assist in prevention of dental caries, whereas in green tea, this mode of inhibition was likely offset by the presence of pectin. Purification of catechins in partially fermented Assam tea with lower-molecular-weight polysaccharide than pectin may be useful for developing oral care products such as toothpaste and oral care gel pastes.}, } @article {pmid27106696, year = {2016}, author = {Waryah, CB and Gogoi-Tiwari, J and Wells, K and Mukkur, T}, title = {An immunological assay for identification of potential biofilm-associated antigens of Staphylococcus aureus.}, journal = {Folia microbiologica}, volume = {61}, number = {6}, pages = {473-478}, pmid = {27106696}, issn = {1874-9356}, mesh = {Adhesins, Bacterial/analysis ; Antibodies, Bacterial/metabolism ; Antigens, Bacterial/*analysis ; Bacterial Adhesion ; Biofilms/*growth & development ; Immunoassay/*methods ; Polystyrenes ; Staphylococcus aureus/*chemistry/*physiology ; }, abstract = {Attachment of bacterial pathogens to the niche tissue in the host is the first step in biofilm formation leading to colonization and establishment of infection in the host. While the most common method used for determining the potential role of a bacterial antigen in biofilm formation has been demonstration of loss of this property using specific knockout mutants, it is an expensive and a laborious procedure. This study describes an alternative immunological assay for identification of attachment antigens of Staphylococcus aureus, potentially important in the development of an effective vaccine against infections caused by this pathogen. The method is based upon the concept of inhibition of attachment of S. aureus to PEGs coated with virulence antigen-specific antibodies. Antibodies used for validation of this assay were specific for ClfA, FnBPA, SdrD, PNAG and α-toxin, accredited biofilm-associated antigens of S. aureus.}, } @article {pmid27106256, year = {2017}, author = {Verplaetse, E and Slamti, L and Gohar, M and Lereclus, D}, title = {Two distinct pathways lead Bacillus thuringiensis to commit to sporulation in biofilm.}, journal = {Research in microbiology}, volume = {168}, number = {4}, pages = {388-393}, doi = {10.1016/j.resmic.2016.03.006}, pmid = {27106256}, issn = {1769-7123}, mesh = {Bacillus thuringiensis/*growth & development/*metabolism/pathogenicity ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Quorum Sensing/physiology ; Spores, Bacterial/*growth & development ; Transcription Factors/metabolism ; }, abstract = {The spore-forming bacterium Bacillus thuringiensis is an efficient biofilm producer, responsible for persistent contamination of industrial food processing systems. B. thuringiensis biofilms are highly heterogeneous bacterial structures in which three distinct cell types controlled by quorum sensing regulators were identified: PlcR-controlled virulent cells, NprR-dependent necrotrophic cells and cells committed to sporulation, a differentiation process controlled by Rap phosphatases and Spo0A-P. Interestingly, a cell lineage study revealed that, in LB medium or in insect larvae, only necrotrophic cells became spores. Here we analyzed cellular differentiation undertaken by cells growing in biofilm in a medium optimized for sporulation. No virulent cells were identified; surprisingly, two distinct routes could lead to differentiation as a spore in this growth condition: the NprR-dependent route, followed by the majority of cells, and the newly identified NprR-independent route, which is followed by 20% of sporulating cells.}, } @article {pmid27105066, year = {2016}, author = {Wang, B and Jin, T and Xu, Q and Liu, H and Ye, Z and Chen, H}, title = {Direct Loading and Tunable Release of Antibiotics from Polyelectrolyte Multilayers To Reduce Bacterial Adhesion and Biofilm Formation.}, journal = {Bioconjugate chemistry}, volume = {27}, number = {5}, pages = {1305-1313}, doi = {10.1021/acs.bioconjchem.6b00118}, pmid = {27105066}, issn = {1520-4812}, mesh = {Acrylic Resins/*chemistry ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects/growth & development ; *Drug Liberation ; Gentamicins/*chemistry/*pharmacology ; Humans ; Kinetics ; Polyethyleneimine/*chemistry ; }, abstract = {Bacteria adhesion on the surface of biomaterials and following biofilm formation are important problems in biomedical applications. The charged antibiotics with small molar mass can hardly deposit alternately with polymers into multilayered films to load the drug. Herein, the (poly(acrylic acid)-gentamicin/poly(ethylenimine))n ((PAA-GS/PEI)n) multilayer film was designed and constructed via a layer-by-layer self-assembly method. Low molar mass GS cations were first combined with polyanion PAA and self-assembled with PEI to form multilayer films showing exponential growth behavior. The GS dosage could be adjusted by changing the layer number of films. Furthermore, the thermal cross-linking method was used to control the release rate of GS in PBS buffer. Owing to the diffusion of GS, a zone of inhibition of about 7.0 mm showed the efficient disinfection activity of the multilayer film. It could also be seen from the biofilm inhibition assay that the multilayer film effectively inhibited bacterial adhesion and biofilm formation. As the drug loading dosage was 160 μg/cm(2), the multilayer films showed very low cytotoxicity against human lens epithelial cells. The present work provides an easy way to load GS into multilayer films which can be applied to surface modification of implants and biomedical devices.}, } @article {pmid27104213, year = {2016}, author = {Moreno-García, J and Mauricio, JC and Moreno, J and García-Martínez, T}, title = {Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition.}, journal = {Data in brief}, volume = {7}, number = {}, pages = {1021-1023}, pmid = {27104213}, issn = {2352-3409}, abstract = {In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC) and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC). Protein functional analysis - based on cellular components and biological process GO terms - was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in "Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation" [1].}, } @article {pmid27102292, year = {2016}, author = {Azab, MA and Allen, MJ and Daniels, JB}, title = {Evaluation of a silver-impregnated coating to inhibit colonization of orthopaedic implants by biofilm forming methicillin-resistant Staphylococcus pseudintermedius.}, journal = {Veterinary and comparative orthopaedics and traumatology : V.C.O.T}, volume = {29}, number = {4}, pages = {347-350}, doi = {10.3415/VCOT-15-08-0134}, pmid = {27102292}, issn = {2567-6911}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms ; Dog Diseases/microbiology/*prevention & control ; Dogs ; Methicillin/pharmacology ; Methicillin-Resistant Staphylococcus aureus/*drug effects/growth & development ; Prostheses and Implants/microbiology/*veterinary ; Silver ; Staphylococcal Infections/*veterinary ; *Titanium ; }, abstract = {OBJECTIVES: To evaluate the in vitro antibacterial activity of a silver-impregnated coating against a biofilm-forming strain of methicillin-resistant Staphylococcus pseudintermedius (MRSP).

METHODS: A clinical MRSP isolate sourced from a failed canine knee implant was evaluated for biofilm production and used in the present study. Using a standard test method and a clinically approved titanium substrate, the antimicrobial activity of a novel silver plasma coating was determined at two times: five minutes after inoculation of the specimens (T0) and after 24 hours of incubation (T24). Scanning electron microscopy was used to evaluate the biofilm formation on specimens.

RESULTS: The tested clinical MRSP isolate was classified as a strong biofilm producer. The silver coating significantly reduced the MRSP growth more than four log steps compared to the non-coated specimens and showed more than 99.98% reduction in the number of colony forming units after 24 hours. Scanning electron microscopy images revealed that silver-coated surfaces did not manifest detectable biofilm, while biofilm formation was readily observed on the control specimens.

CLINICAL SIGNIFICANCE: The silver coating exhibited excellent activity against the multidrug resistant biofilm-forming MRSP isolate. The next stage of this work will involve testing in an animal model of orthopaedic infection. Positive results from animal studies would support the introduction of the silver plasma coating as a new strategy for preventing implant contamination, biofilm formation, and surgical infection in dogs undergoing orthopaedic surgery.}, } @article {pmid27102130, year = {2016}, author = {Nakamura, Y and Yamamoto, N and Kino, Y and Yamamoto, N and Kamei, S and Mori, H and Kurokawa, K and Nakashima, N}, title = {Establishment of a multi-species biofilm model and metatranscriptomic analysis of biofilm and planktonic cell communities.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {16}, pages = {7263-7279}, doi = {10.1007/s00253-016-7532-6}, pmid = {27102130}, issn = {1432-0614}, mesh = {Bacteria/classification/*genetics ; Biofilms/*growth & development ; Flagella/genetics ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Iron/metabolism ; Japan ; Microbiota/*genetics ; Oligonucleotide Array Sequence Analysis ; Plankton/genetics/*growth & development ; RNA, Ribosomal, 16S/genetics ; Rivers/*microbiology ; Sulfur/metabolism ; Transcriptome/genetics ; }, abstract = {We collected several biofilm samples from Japanese rivers and established a reproducible multi-species biofilm model that can be analyzed in laboratories. Bacterial abundance at the generic level was highly similar between the planktonic and biofilm communities, whereas comparative metatranscriptomic analysis revealed many upregulated and downregulated genes in the biofilm. Many genes involved in iron-sulfur metabolism, stress response, and cell envelope function were upregulated; biofilm formation is mediated by an iron-dependent signaling mechanism and the signal is relayed to stress-responsive and cell envelope function genes. Flagella-related gene expression was regulated depending upon the growth phase, indicating different roles of flagella during the adherence, maturation, and dispersal steps of biofilm formation. Downregulation of DNA repair genes was observed, indicating that spontaneous mutation frequency would be elevated within the biofilm and that the biofilm is a cradle for generating novel genetic traits. Although the significance remains unclear, genes for rRNA methyltransferase, chromosome partitioning, aminoacyl-tRNA synthase, and cysteine, methionine, leucine, thiamine, nucleotide, and fatty acid metabolism were found to be differentially regulated. These results indicate that planktonic and biofilm communities are in different dynamic states. Studies on biofilm and sessile cells, which have received less attention, are important for understanding microbial ecology and for designing tailor-made anti-biofilm drugs.}, } @article {pmid27102127, year = {2016}, author = {Ciandrini, E and Campana, R and Casettari, L and Perinelli, DR and Fagioli, L and Manti, A and Palmieri, GF and Papa, S and Baffone, W}, title = {Characterization of biosurfactants produced by Lactobacillus spp. and their activity against oral streptococci biofilm.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {15}, pages = {6767-6777}, doi = {10.1007/s00253-016-7531-7}, pmid = {27102127}, issn = {1432-0614}, mesh = {Anti-Bacterial Agents/*metabolism ; Bacterial Adhesion/drug effects ; Biofilms/*growth & development ; Lactobacillus acidophilus/*metabolism ; Lacticaseibacillus paracasei/*metabolism ; Limosilactobacillus reuteri/*metabolism ; Lacticaseibacillus rhamnosus/*metabolism ; Microbial Sensitivity Tests ; Streptococcus mutans/drug effects/*growth & development ; Streptococcus oralis/drug effects/*growth & development ; Surface Tension/drug effects ; Surface-Active Agents/*metabolism/pharmacology ; Titanium ; }, abstract = {Lactic acid bacteria (LAB) can interfere with pathogens through different mechanisms; one is the production of biosurfactants, a group of surface-active molecules, which inhibit the growth of potential pathogens. In the present study, biosurfactants produced by Lactobacillus reuteri DSM 17938, Lactobacillus acidophilus DDS-1, Lactobacillus rhamnosus ATCC 53103, and Lactobacillus paracasei B21060 were dialyzed (1 and 6 kDa) and characterized in term of reduction of surface tension and emulsifying activity. Then, aliquots of the different dialyzed biosurfactants were added to Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 in the culture medium during the formation of biofilm on titanium surface and the efficacy was determined by agar plate count, biomass analyses, and flow cytometry. Dialyzed biosurfactants showed abilities to reduce surface tension and to emulsifying paraffin oil. Moreover, they significantly inhibited the adhesion and biofilm formation on titanium surface of S. mutans and S. oralis in a dose-dependent way, as demonstrated by the remarkable decrease of cfu/ml values and biomass production. The antimicrobial properties observed for dialyzed biosurfactants produced by the tested lactobacilli opens future prospects for their use against microorganisms responsible of oral diseases.}, } @article {pmid27100887, year = {2016}, author = {Cao, B and Christophersen, L and Kolpen, M and Jensen, PØ and Sneppen, K and Høiby, N and Moser, C and Sams, T}, title = {Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model.}, journal = {PloS one}, volume = {11}, number = {4}, pages = {e0153616}, pmid = {27100887}, issn = {1932-6203}, mesh = {*Alginates ; Anti-Bacterial Agents/*metabolism/pharmacokinetics ; *Biofilms ; Glucuronic Acid ; Hexuronic Acids ; Models, Chemical ; Tobramycin/*metabolism/pharmacokinetics ; }, abstract = {Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The antibiotic killing of bacteria in biofilms is generally known to be reduced by 100-1000 times relative to planktonic bacteria. This makes such infections difficult to treat. We have therefore proposed that biofilms can be regarded as an independent compartment with distinct pharmacokinetics. To elucidate this pharmacokinetics we have measured the penetration of the tobramycin into seaweed alginate beads which serve as a model of the extracellular polysaccharide matrix in P. aeruginosa biofilm. We find that, rather than a normal first order saturation curve, the concentration of tobramycin in the alginate beads follows a power-law as a function of the external concentration. Further, the tobramycin is observed to be uniformly distributed throughout the volume of the alginate bead. The power-law appears to be a consequence of binding to a multitude of different binding sites. In a diffusion model these results are shown to produce pronounced retardation of the penetration of tobramycin into the biofilm. This filtering of the free tobramycin concentration inside biofilm beads is expected to aid in augmenting the survival probability of bacteria residing in the biofilm.}, } @article {pmid27100808, year = {2016}, author = {Pini-Prato, G and Magnani, C and Rotundo, R}, title = {Nonsurgical Treatment of Peri-implantitis Using the Biofilm Decontamination Approach: A Case Report Study.}, journal = {The International journal of periodontics & restorative dentistry}, volume = {36}, number = {3}, pages = {383-391}, doi = {10.11607/prd.2653}, pmid = {27100808}, issn = {1945-3388}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Decontamination/*methods ; Dental Implants/*adverse effects ; Humans ; Peri-Implantitis/*drug therapy ; }, abstract = {The aim of this preliminary study is to show the effect of the biofilm decontamination approach on peri-implantitis treatment. Clinical cases showing peri-implantitis were treated using an oral tissue decontaminant material that contains a concentrated aqueous mixture of hydroxybenzenesulfonic and hydroxymethoxybenzenesulfonic acids and sulfuric acid. The material was positioned in the pocket around the implant without anesthesia in nonsurgically treated cases. No instrumentation and no systemic or local antibiotics were used in any of the cases. A questionnaire was used for each patient to record the pain/discomfort felt when the material was administered. All of the treated cases healed well and rapidly. The infections were quickly resolved without complications. The momentary pain on introduction of the material was generally well tolerated and completely disappeared after a few seconds. The biofilm decontamination approach seems to be a very promising technique for the treatment of peri-implantitis. The local application of this material avoids the use of systemic or local antibiotics.}, } @article {pmid27101275, year = {2016}, author = {Preuß, A and Bornhütter, T and Färber, A and Schaller, C and Röder, B}, title = {Photodynamic inactivation of biofilm building microorganisms by photoactive facade paints.}, journal = {Journal of photochemistry and photobiology. B, Biology}, volume = {160}, number = {}, pages = {79-85}, doi = {10.1016/j.jphotobiol.2016.04.008}, pmid = {27101275}, issn = {1873-2682}, mesh = {Anti-Infective Agents/*pharmacology ; *Biofilms ; Humans ; *Paint ; Photosensitizing Agents/*pharmacology ; }, abstract = {This study was performed as a proof of concept for singlet oxygen generating facade paint as an alternative to conventional biocide containing facade paint for the prevention of biofilm growth on outdoor walls. Biofilms on outdoor walls cause esthetic problems and economic damage. Therefore facade paints often contain biocides. However commercially available biocides may have a series of adverse effects on living organisms as well as harmful environmental effects. Furthermore, biocides are increasingly designed to be more effective and are environmentally persistent. Thus, an eco-friendly and non-harmful to human health alternative to conventional biocides in wall color is strongly recommended. The well-known photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) was used as an additive in a commercially available facade paint. The generation of singlet molecular oxygen was shown using time resolved 2D measurements of the singlet oxygen luminescence. The photodynamic activity of the photosensitizer in the facade paint was demonstrated by phototoxicity tests with defined mold fungi and a mixture of microorganisms harvested from native outdoor biofilms as model organisms. It was proven in general that it is possible to inhibit the growth of biofilm forming microorganisms growing on solid wall paint surfaces by the cationic photosensitizer TMPyP added to the facade paint using daylight conditions for illumination in 12h light and dark cycles.}, } @article {pmid27101249, year = {2016}, author = {Harris, LG and Murray, S and Pascoe, B and Bray, J and Meric, G and Mageiros, L and Wilkinson, TS and Jeeves, R and Rohde, H and Schwarz, S and de Lencastre, H and Miragaia, M and Rolo, J and Bowden, R and Jolley, KA and Maiden, MC and Mack, D and Sheppard, SK}, title = {Correction: Biofilm Morphotypes and Population Structure among Staphylococcus epidermidis from Commensal and Clinical Samples.}, journal = {PloS one}, volume = {11}, number = {4}, pages = {e0154510}, pmid = {27101249}, issn = {1932-6203}, support = {G0801929/MRC_/Medical Research Council/United Kingdom ; }, } @article {pmid27099694, year = {2016}, author = {Seifi, K and Kazemian, H and Heidari, H and Rezagholizadeh, F and Saee, Y and Shirvani, F and Houri, H}, title = {Evaluation of Biofilm Formation Among Klebsiella pneumoniae Isolates and Molecular Characterization by ERIC-PCR.}, journal = {Jundishapur journal of microbiology}, volume = {9}, number = {1}, pages = {e30682}, pmid = {27099694}, issn = {2008-3645}, abstract = {BACKGROUND: Klebsiella pneumoniae is among the most frequently recovered etiologic agents from nosocomial infections. This opportunistic pathogen can generate a thick layer of biofilm as one of its important virulence factors, enabling the bacteria to attach to living or abiotic surfaces, which contributes to drug resistance.

OBJECTIVES: The resistance of biofilm-mediated infections to effective chemotherapy has adverse effects on patient outcomes and survival. Therefore, the aim of the present study was to evaluate the biofilm-formation capacity of clinical K. pneumoniae isolates and to perform a molecular characterization using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) to determine the dominant biofilm-producing genotype.

PATIENTS AND METHODS: In the present study, 94 K. pneumoniae isolates were obtained from two hospitals in Tehran, Iran. Biofilm formation was assayed by a modified procedure, then ERIC-PCR was carried out.

RESULTS: The distributions of the clinical specimens used in this study were 61.7% from urine, 18.1% from wounds, 11.7% from sputum, and 8.5% from blood. Among these isolates, 33% formed fully established biofilms, 52.1% were categorized as moderately biofilm-producing, 8.5% formed weak biofilms, and 6.4% were non-biofilm-producers. Genotyping of K. pneumoniae revealed 31 different ERIC types. Biofilm-formation ability in a special ERIC type was not observed.

CONCLUSIONS: Our results indicated that an enormous proportion of K. pneumoniae isolated from sputum and surgical-wound swabs produced fully established biofilms. It is reasonable to assume the existence of a relationship between the site of infection and the formation of biofilm. A high level of genetic diversity among the K. pneumoniae strains was observed.}, } @article {pmid27099692, year = {2016}, author = {Rehman, S and Mujtaba Ghauri, S and Sabri, AN}, title = {Impact of Plant Extracts and Antibiotics on Biofilm Formation of Clinical Isolates From Otitis Media.}, journal = {Jundishapur journal of microbiology}, volume = {9}, number = {1}, pages = {e29483}, pmid = {27099692}, issn = {2008-3645}, abstract = {BACKGROUND: Otitis media can lead to severe health consequences, and is the most common reason for antibiotic prescriptions and biofilm-mediated infections. However, the increased pattern of drug resistance in biofilm forming bacteria complicates the treatment of such infections.

OBJECTIVES: This study was aimed to estimate the biofilm formation potential of the clinical isolates of otitis media, and to evaluate the efficacy of antibiotics and plant extracts as alternative therapeutic agents in biofilm eradication.

MATERIALS AND METHODS: The ear swab samples collected from the otitis media patients visiting the Mayo Hospital in Lahore were processed to isolate the bacteria, which were characterized using morphological, biochemical, and molecular (16S rRNA ribotyping) techniques. Then, the minimum inhibitory concentrations (MICs) of the antibiotics and crude plant extracts were measured against the isolates. The cell surface hydrophobicity and biofilm formation potential were determined, both qualitatively and quantitatively, with and without antibiotics. Finally, the molecular characterization of the biofilm forming proteins was done by amplifying the ica operon.

RESULTS: Pseudomonas aeruginosa (KC417303-05), Staphylococcus hemolyticus (KC417306), and Staphylococcus hominis (KC417307) were isolated from the otitis media specimens. Among the crude plant extracts, Acacia arabica showed significant antibacterial characteristics (MIC up to 13 mg/ml), while these isolates exhibited sensitivity towards ciprofloxacin (MIC 0.2 µg/mL). All of the bacterial strains had hydrophobic cellular surfaces that helped in their adherence to abiotic surfaces, leading to strong biofilm formation potential (up to 7 days). Furthermore, the icaC gene encoding polysaccharide intercellular adhesion protein was amplified from S. hemolyticus.

CONCLUSIONS: The bacterial isolates exhibited strong biofilm formation potential, while the extracts of Acacia arabica significantly inhibited biofilm formation among the isolates and, therefore, could be executed in the development of cost-effective biofilm inhibitor medicines.}, } @article {pmid27097059, year = {2016}, author = {Turonova, H and Neu, TR and Ulbrich, P and Pazlarova, J and Tresse, O}, title = {The biofilm matrix of Campylobacter jejuni determined by fluorescence lectin-binding analysis.}, journal = {Biofouling}, volume = {32}, number = {5}, pages = {597-608}, doi = {10.1080/08927014.2016.1169402}, pmid = {27097059}, issn = {1029-2454}, mesh = {*Biofilms ; Campylobacter jejuni/*physiology ; Fluorescence ; Glycoconjugates/analysis ; Lectins/*metabolism ; Lipopolysaccharides/analysis ; Polysaccharides, Bacterial/analysis ; }, abstract = {Campylobacter jejuni is responsible for the most common bacterial foodborne gastroenteritis. Despite its fastidious growth, it can survive harsh conditions through biofilm formation. In this work, fluorescence lectin-binding analysis was used to determine the glycoconjugates present in the biofilm matrix of two well-described strains. Screening of 72 lectins revealed strain-specific patterns with six lectins interacting with the biofilm matrix of both strains. The most common sugar moiety contained galactose and N-acetylgalactosamine. Several lectins interacted with N-acetylglucosamine and sialic acid, probably originated from the capsular polysaccharides, lipooligosaccharides and N-glycans of C. jejuni. In addition, glycoconjugates containing mannose and fucose were detected within the biofilm, which have not previously been found in the C. jejuni envelope. Detection of thioflavin T and curcumin highlighted the presence of amyloids in the cell envelope without association with specific cell appendages. The lectins ECA, GS-I, HMA and LEA constitute a reliable cocktail to detect the biofilm matrix of C. jejuni.}, } @article {pmid27095620, year = {2015}, author = {Bulacio, Mde L and Galván, LR and Gaudioso, C and Cangemi, R and Erimbaue, MI}, title = {Enterococcus Faecalis Biofilm. Formation and Development in Vitro Observed by Scanning Electron Microscopy.}, journal = {Acta odontologica latinoamericana : AOL}, volume = {28}, number = {3}, pages = {210-214}, pmid = {27095620}, issn = {1852-4834}, mesh = {*Biofilms ; Dental Pulp Cavity ; Enterococcus faecalis ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; }, abstract = {Biofilm produced by Enterococcus faecalis isolated from root canals was detected by growing it on microplates and using 10% crystal violet stain, elution with alcohol and three procedures: no fixation, heat fixation and 10% formaldehyde fixation. The biofilm was evaluated using a Versamax Microplate Reader (USA). Twenty sterile root portions were incubated in TS broth with E. faecalis (108) for 48 hours, 4, 7, 14 and 30 days, after which they were processed and observed by scanning electron microscopy (SEM). Significantly more biofilm was found on the microplates for formaldehyde fixation than for heat fixation or no fixation (ANOVA p<0.0001). SEM showed E. faecalis growth at all times and biofilm development as from 14 days' incubation. Fixation with 10% formaldehyde was the most appropriate technique for detecting E. faecalis biofilm development on microplates. SEM confirmed biofilm formation after 14 days incubation.}, } @article {pmid27094999, year = {2016}, author = {Meng, X and Zhang, L and Hou, B and Liu, X and Li, S}, title = {Oxygen-Free Condition Inhibited Biofilm Formation in Extraintestinal Pathogenic Escherichia coli Strain PPECC42 Through Preventing Curli Production.}, journal = {Current microbiology}, volume = {73}, number = {2}, pages = {153-158}, pmid = {27094999}, issn = {1432-0991}, mesh = {Animals ; *Biofilms ; Escherichia coli Infections/microbiology/*veterinary ; Escherichia coli Proteins/genetics/*metabolism ; Extraintestinal Pathogenic Escherichia coli/genetics/*physiology ; Fimbriae, Bacterial/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Lung/microbiology ; Oxygen/*metabolism ; Swine ; Swine Diseases/*microbiology ; }, abstract = {Extraintestinal pathogenic Escherichia coli (ExPEC) is an important zoonotic and foodborne pathogen. Biofilms are specially structured communities for bacteria to survive in different hostile environments and can protect the bacteria from eradication by the host and external factors. In this study, we found that oxygen is definitely required for biofilm formation in ExPEC strain PPECC42. Aerobically growing ExPEC showed a bdar (brown, dry, and rough) morphotype, whereas anaerobically growing ExPEC showed a saw (smooth and white) morphotype. Under anaerobic condition, curli fimbriae did not accumulate and the expression levels of curli biosynthesis-related genes including csgB, csgD, and rpoS decreased significantly; in contrast, the expression level of h-ns, of which the encoding protein is a repressor for csgD transcription, increased significantly. Taken together, the results suggested that oxygen-free condition limited ExPEC strain PPECC42 biofilm formation mainly through preventing curli accumulation by affecting the transcriptional levels of curli biosynthesis-related genes.}, } @article {pmid27094331, year = {2016}, author = {Richmond, GE and Evans, LP and Anderson, MJ and Wand, ME and Bonney, LC and Ivens, A and Chua, KL and Webber, MA and Sutton, JM and Peterson, ML and Piddock, LJ}, title = {The Acinetobacter baumannii Two-Component System AdeRS Regulates Genes Required for Multidrug Efflux, Biofilm Formation, and Virulence in a Strain-Specific Manner.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00430-16}, pmid = {27094331}, issn = {2150-7511}, support = {G0801977/MRC_/Medical Research Council/United Kingdom ; G0901366/MRC_/Medical Research Council/United Kingdom ; G9818340/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/drug effects/genetics/*metabolism/*pathogenicity ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Drug Resistance, Multiple, Bacterial ; *Gene Expression Regulation, Bacterial ; Humans ; Membrane Transport Proteins/genetics/*metabolism ; Species Specificity ; Virulence ; }, abstract = {The opportunistic pathogen Acinetobacter baumannii is able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in an ex vivo porcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion of adeB impacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 for Galleria mellonella RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions. For example, A. baumannii lacking AdeRS displayed decreased expression of adeABC, pil genes, com genes, and a pgaC-like gene, whereas loss of AdeB resulted in increased expression of pil and com genes and decreased expression of ferric acinetobactin transport system genes. These data define the scope of AdeRS-mediated regulation, show that changes in the production of AdeABC mediate important phenotypes controlled by AdeRS, and suggest that AdeABC is a viable target for antimicrobial drug and antibiofilm discovery [corrected].}, } @article {pmid27093630, year = {2016}, author = {Al-Ahmad, A and Karygianni, L and Schulze Wartenhorst, M and Bächle, M and Hellwig, E and Follo, M and Vach, K and Han, JS}, title = {Bacterial adhesion and biofilm formation on yttria-stabilized, tetragonal zirconia and titanium oral implant materials with low surface roughness - an in situ study.}, journal = {Journal of medical microbiology}, volume = {65}, number = {7}, pages = {596-604}, doi = {10.1099/jmm.0.000267}, pmid = {27093630}, issn = {1473-5644}, abstract = {Bacterially-driven mucosal inflammation and the development of periimplantitis can lead to oral implant failure. In this study, initial bacterial adhesion after 2 h, and biofilm formation after 1 day and 3 days, were analysed in situ on novel 3 mol % yttria-stabilized tetragonal zirconia polycrystal samples, as well as on alumina and niobium co-doped yttria-stabilized tetragonal zirconia samples. Pure titanium implant material and bovine enamel slabs served as controls. The initially adherent oral bacteria were determined by 4',6-diamidino-2-phenylindole-staining. Biofilm thickness, surface covering grade and content of oral streptococci within the biofilm were measured by fluorescence in situ hybridization. No significant differences between the ceramic and titanium surfaces were detectable for either initial bacterial adhesion or the oral streptococci content of the in situ biofilm. The oral biofilm thickness on the implant surfaces were almost doubled after three days compared to the first day of oral exposure. Nevertheless, the biofilm thickness values among the different implant surfaces and controls did not differ significantly for any time point of measurement after 1 day or 3 days of biofilm formation. Significant differences in the covering grade were only detected between day 1 and day 3 for each tested implant material group. The content of oral streptococci increased significantly in parallel with the increase in biofilm age from day 1 to day 3. In conclusion, oral implant zirconia surfaces with low surface roughness are comparable to titanium surfaces with respect to initial bacterial adhesion and biofilm formation.}, } @article {pmid27091926, year = {2016}, author = {Vidlak, D and Kielian, T}, title = {Infectious Dose Dictates the Host Response during Staphylococcus aureus Orthopedic-Implant Biofilm Infection.}, journal = {Infection and immunity}, volume = {84}, number = {7}, pages = {1957-1965}, pmid = {27091926}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacterial Load ; *Biofilms ; Cytokines/biosynthesis ; Disease Models, Animal ; Host-Pathogen Interactions/*immunology ; Leukocytes/immunology/metabolism/pathology ; Male ; Mice ; Mice, Knockout ; Prosthesis-Related Infections/*immunology/metabolism/*microbiology/pathology ; Staphylococcal Infections/*immunology/metabolism/*microbiology/pathology ; Staphylococcus aureus/*growth & development/*immunology/isolation & purification ; }, abstract = {Staphylococcus aureus is a leading cause of prosthetic joint infections (PJIs) that are typified by biofilm formation. Given the diversity of S. aureus strains and their propensity to cause community- or hospital-acquired infections, we investigated whether the immune response and biofilm growth during PJI were conserved among distinct S. aureus clinical isolates. Three S. aureus strains representing USA200 (UAMS-1), USA300 (LAC), and USA400 (MW2) lineages were equally effective at biofilm formation in a mouse model of PJI and elicited similar leukocyte infiltrates and cytokine/chemokine profiles. Another factor that may influence the course of PJI is infectious dose. In particular, higher bacterial inocula could accelerate biofilm formation and alter the immune response, making it difficult to discern underlying pathophysiological mechanisms. To address this issue, we compared the effects of two bacterial doses (10(3) or 10(5) CFU) on inflammatory responses in interleukin-12p40 (IL-12p40) knockout mice that were previously shown to have reduced myeloid-derived suppressor cell recruitment concomitant with bacterial clearance after low-dose challenge (10(3) CFU). Increasing the infectious dose of LAC to 10(5) CFU negated these differences in IL-12p40 knockout animals, demonstrating the importance of bacterial inoculum on infection outcome. Collectively, these observations highlight the importance of considering infectious dose when assessing immune responsiveness, whereas biofilm formation during PJI is conserved among clinical isolates commonly used in mouse S. aureus infection models.}, } @article {pmid27091884, year = {2016}, author = {Deal, A and Klein, D and Lopolito, P and Schwarz, JS}, title = {Cleaning and Disinfection of Bacillus cereus Biofilm.}, journal = {PDA journal of pharmaceutical science and technology}, volume = {70}, number = {3}, pages = {208-217}, doi = {10.5731/pdajpst.2014.005165}, pmid = {27091884}, issn = {1948-2124}, mesh = {Bacillus cereus/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Disinfectants/administration & dosage ; Disinfection/*methods ; Equipment Contamination/*prevention & control ; Spores, Bacterial/*drug effects/growth & development ; }, abstract = {UNLABELLED: Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility.

LAY ABSTRACT: Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility.}, } @article {pmid27091004, year = {2016}, author = {Scavone, P and Iribarnegaray, V and Caetano, AL and Schlapp, G and Härtel, S and Zunino, P}, title = {Fimbriae have distinguishable roles in Proteus mirabilis biofilm formation.}, journal = {Pathogens and disease}, volume = {74}, number = {5}, pages = {}, doi = {10.1093/femspd/ftw033}, pmid = {27091004}, issn = {2049-632X}, mesh = {Biofilms/*growth & development ; Culture Media ; Fimbriae, Bacterial/*physiology ; Humans ; Proteus Infections/microbiology ; Proteus mirabilis/*physiology ; Urinary Catheters/microbiology ; }, abstract = {Proteus mirabilis is one of the most common etiological agents of complicated urinary tract infections, especially those associated with catheterization. This is related to the ability of P. mirabilis to form biofilms on different surfaces. This pathogen encodes 17 putative fimbrial operons, the highest number found in any sequenced bacterial species so far. The present study analyzed the role of four P. mirabilis fimbriae (MR/P, UCA, ATF and PMF) in biofilm formation using isogenic mutants. Experimental approaches included migration over catheter, swimming and swarming motility, the semiquantitative assay based on adhesion and crystal violet staining, and biofilm development by immunofluorescence and confocal microscopy. Different assays were performed using LB or artificial urine. Results indicated that the different fimbriae contribute to the formation of a stable and functional biofilm. Fimbriae revealed particular associated roles. First, all the mutants showed a significantly reduced ability to migrate across urinary catheter sections but neither swimming nor swarming motility were affected. However, some mutants formed smaller biofilms compared with the wild type (MRP and ATF) while others formed significantly larger biofilms (UCA and PMF) showing different bioarchitecture features. It can be concluded that P. mirabilis fimbriae have distinguishable roles in the generation of biofilms, particularly in association with catheters.}, } @article {pmid27090887, year = {2016}, author = {Yang, C and Fang, S and Chen, D and Wang, J and Liu, F and Xia, C}, title = {The possible role of bacterial signal molecules N-acyl homoserine lactones in the formation of diatom-biofilm (Cylindrotheca sp.).}, journal = {Marine pollution bulletin}, volume = {107}, number = {1}, pages = {118-124}, doi = {10.1016/j.marpolbul.2016.04.010}, pmid = {27090887}, issn = {1879-3363}, mesh = {*Acyl-Butyrolactones ; *Bacteria ; Biofilms/*drug effects ; Calcium ; Chlorophyll ; Chlorophyll A ; Diatoms/*drug effects ; Quorum Sensing ; }, abstract = {Bacterial quorum sensing signal molecules N-acyl homoserine lactones (AHLs) (C10-HSL, 3-OXO-C10-HSL and 3-OH-C10-HSL) as possible chemical cues were employed to investigate the role in the formation of fouling diatom-biofilm (Cylindrotheca sp.). Results showed that AHLs promoted Chlorophyll a (Chl.a) and extracellular polymeric substance (EPS) contents in the diatom-biofilm. In the presence of AHLs-inhibitor 3, 4-Dibromo-2(5)H-furanone, which was used to avoid the possible interference of AHLs from bacteria, AHLs also increased the Chl.a and EPS contents. Scanning electron microscope and confocal laser scanning microscope analysis further demonstrated that AHLs promoted the formation of the diatom-biofilm. Non-invasive micro-test technique showed that AHLs promoted Ca(2+) efflux in Cylindrotheca sp., which implied that Ca(2+) might be correlated with AHLs-induced positive effect on the formation of diatom-biofilm. This study provides direct evidences that AHLs play an important role in developing the diatom-biofilm and AHLs-inhibitors might be promising active agents in marine antifouling.}, } @article {pmid27090825, year = {2016}, author = {O'May, C and Amzallag, O and Bechir, K and Tufenkji, N}, title = {Cranberry derivatives enhance biofilm formation and transiently impair swarming motility of the uropathogen Proteus mirabilis HI4320.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {6}, pages = {464-474}, doi = {10.1139/cjm-2015-0715}, pmid = {27090825}, issn = {1480-3275}, mesh = {Biofilms/drug effects/*growth & development ; Catheter-Related Infections/*microbiology ; Fruit/chemistry ; Humans ; Plant Extracts/chemistry/isolation & purification/*pharmacology ; Proteus mirabilis/*drug effects/growth & development/physiology ; Urinary Tract Infections/*microbiology ; Vaccinium macrocarpon/*chemistry ; }, abstract = {Proteus mirabilis is a major cause of catheter-associated urinary tract infection (CAUTI), emphasizing that novel strategies for targeting this bacterium are needed. Potential targets are P. mirabilis surface-associated swarming motility and the propensity of these bacteria to form biofilms that may lead to catheter blockage. We previously showed that the addition of cranberry powder (CP) to lysogeny broth (LB) medium resulted in impaired P. mirabilis swarming motility over short time periods (up to 16 h). Herein, we significantly expanded on those findings by exploring (i) the effects of cranberry derivatives on biofilm formation of P. mirabilis, (ii) whether swarming inhibition occurred transiently or over longer periods more relevant to real infections (∼3 days), (iii) whether swarming was also blocked by commercially available cranberry juices, (iv) whether CP or cranberry juices exhibited effects under natural urine conditions, and (v) the effects of cranberry on medium pH, which is an indirect indicator of urease activity. At short time scales (24 h), CP and commercially available pure cranberry juice impaired swarming motility and repelled actively swarming bacteria in LB medium. Over longer time periods more representative of infections (∼3 days), the capacity of the cranberry material to impair swarming diminished and bacteria would start to migrate across the surface, albeit by exhibiting a different motility phenotype to the regular "bull's-eye" swarming phenotype of P. mirabilis. This bacterium did not swarm on urine agar or LB agar supplemented with urea, suggesting that any potential application of anti-swarming compounds may be better suited to settings external to the urine environment. Anti-swarming effects were confounded by the ability of cranberry products to enhance biofilm formation in both LB and urine conditions. These findings provide key insights into the long-term strategy of targeting P. mirabilis CAUTIs.}, } @article {pmid27090719, year = {2016}, author = {Zheng, Z and Li, Z and Ma, J and Du, J and Chen, G and Bian, W and Li, J and Zhao, B}, title = {The nitritation performance of biofilm reactor for treating domestic wastewater under high dissolved oxygen.}, journal = {Journal of environmental sciences (China)}, volume = {42}, number = {}, pages = {267-274}, doi = {10.1016/j.jes.2015.09.006}, pmid = {27090719}, issn = {1001-0742}, mesh = {Bacteria ; Biofilms ; Bioreactors/*microbiology ; *Nitrification ; Oxygen ; Waste Disposal, Fluid/*methods ; Wastewater/chemistry/*microbiology ; }, abstract = {The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater. The reactor was operated in continuous feed mode from phases 1 to 3. The dissolved oxygen (DO) was controlled at 3.5-7 mg/L throughout the experiment. The biofilm reactor showed excellent nitritation performance after the inoculation of nitrifying sludge, with the hydraulic retention time being reduced from 24 to 7 hr. Above 90% nitrite accumulation ratio (NAR) was maintained in phase 1. Afterwards, nitratation occurred with the low NH4(+)-N concentration in the reactor. The improvement of NH4(+)-N concentration to 20-35 mg/L had a limited effect on the recovery of nitritation. However, nitritation recovered rapidly when sequencing batch feed mode was adopted in phase 4, with the effluent NH4(+)-N concentration above 7 mg/L. The improvement of ammonia oxidizing bacteria (AOB) activity and the combined inhibition effect of free ammonia (FA) and free nitrous acid (FNA) on the nitrite oxidizing bacteria (NOB) were two key factors for the rapid recovery of nitritation. Sludge activity was obtained in batch tests. The results of batch tests had a good relationship with the long term operation performance of the biofilm reactor.}, } @article {pmid27089967, year = {2016}, author = {Yi, L and Wang, Y and Ma, Z and Lin, HX and Xu, B and Grenier, D and Fan, HJ and Lu, CP}, title = {Identification and characterization of a Streptococcus equi ssp. zooepidemicus immunogenic GroEL protein involved in biofilm formation.}, journal = {Veterinary research}, volume = {47}, number = {}, pages = {50}, pmid = {27089967}, issn = {1297-9716}, mesh = {Animals ; Antibodies, Bacterial ; Bacterial Proteins/*genetics/immunology ; *Biofilms ; Chaperonin 60/*genetics/immunology ; Female ; Immunization ; Immunoproteins/genetics/immunology ; Mice ; Mice, Inbred ICR ; Recombinant Proteins/genetics/immunology ; Streptococcus equi/genetics/immunology/*physiology ; }, abstract = {Streptococcus equi ssp. zooepidemicus (S. equi spp. zooepidemicus) is an opportunistic pathogen that causes major economic losses in the swine industry in China and is also a threat for human health. Biofilm formation by this bacterium has been previously reported. In this study, we used an immunoproteomic approach to search for immunogenic proteins expressed by biofilm-grown S. equi spp. zooepidemicus. Seventeen immunoreactive proteins were found, of which nine common immunoreactive proteins were identified in planktonic and biofilm-grown bacteria. The immunogenicity and protective efficacy of the S. equi spp. zooepidemicus immunoreactive GroEL chaperone protein was further investigated in mice. The protein was expressed in vivo and elicited high antibody titers following S. equi spp. zooepidemicus infections of mice. An animal challenge experiment with S. equi spp. zooepidemicus showed that 75% of mice immunized with the GroEL protein were protected. Using in vitro biofilm inhibition assays, evidence was obtained that the chaperonin GroEL may represent a promising target for the prevention and treatment of persistent S. equi spp. zooepidemicus biofilm infections. In summary, our results suggest that the recombinant GroEL protein, which is involved in biofilm formation, may efficiently stimulate an immune response, which protects against S. equi spp. zooepidemicus infections. It may therefore be a candidate of interest to be included in vaccines against S. equi spp. zooepidemicus infections.}, } @article {pmid27087525, year = {2016}, author = {Matsubara, VH and Wang, Y and Bandara, HMHN and Mayer, MPA and Samaranayake, LP}, title = {Probiotic lactobacilli inhibit early stages of Candida albicans biofilm development by reducing their growth, cell adhesion, and filamentation.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {14}, pages = {6415-6426}, doi = {10.1007/s00253-016-7527-3}, pmid = {27087525}, issn = {1432-0614}, mesh = {*Antibiosis ; Biofilms ; Candida albicans/*growth & development ; Cell Adhesion ; Culture Media ; Hyphae/growth & development ; Lactobacillus acidophilus/*physiology ; Lacticaseibacillus rhamnosus/*physiology ; *Probiotics ; }, abstract = {We evaluated the inhibitory effects of the probiotic Lactobacillus species on different phases of Candida albicans biofilm development. Quantification of biofilm growth and ultrastructural analyses were performed on C. albicans biofilms treated with Lactobacillus rhamnosus, Lactobacillus casei, and Lactobacillus acidophilus planktonic cell suspensions as well as their supernatants. Planktonic lactobacilli induced a significant reduction (p < 0.05) in the number of biofilm cells (25.5-61.8 %) depending on the probiotic strain and the biofilm phase. L. rhamnosus supernatants had no significant effect on the mature biofilm (p > 0.05), but significantly reduced the early stages of Candida biofilm formation (p < 0.01). Microscopic analyses revealed that L. rhamnosus suspensions reduced Candida hyphal differentiation, leading to a predominance of budding growth. All lactobacilli negatively impacted C. albicans yeast-to-hyphae differentiation and biofilm formation. The inhibitory effects of the probiotic Lactobacillus on C. albicans entailed both cell-cell interactions and secretion of exometabolites that may impact on pathogenic attributes associated with C. albicans colonization on host surfaces and yeast filamentation. This study clarifies, for the first time, the mechanics of how Lactobacillus species may antagonize C. albicans host colonization. Our data elucidate the inhibitory mechanisms that define the probiotic candicidal activity of lactobacilli, thus supporting their utility as an adjunctive therapeutic mode against mucosal candidal infections.}, } @article {pmid27086715, year = {2017}, author = {Takahashi, C and Muto, S and Yamamoto, H}, title = {A microscopy method for scanning transmission electron microscopy imaging of the antibacterial activity of polymeric nanoparticles on a biofilm with an ionic liquid.}, journal = {Journal of biomedical materials research. Part B, Applied biomaterials}, volume = {105}, number = {6}, pages = {1432-1437}, doi = {10.1002/jbm.b.33680}, pmid = {27086715}, issn = {1552-4981}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects ; Chitosan/chemistry/pharmacology ; *Ionic Liquids/chemistry/pharmacology ; Lactic Acid/chemistry/pharmacology ; *Microscopy, Electron, Scanning Transmission ; Nanoparticles/*chemistry/ultrastructure ; Polyglycolic Acid/chemistry/pharmacology ; Polylactic Acid-Polyglycolic Acid Copolymer ; *Staphylococcus epidermidis/physiology/ultrastructure ; }, abstract = {In this study, we developed a scanning transmission electron microscopy (STEM) method for imaging the antibacterial activity of organic polymeric nanoparticles (NPs) toward biofilms formed by Staphylococcus epidermidis bacterial cells, for optimizing NPs to treat biofilm infections. The combination of sample preparation method using a hydrophilic ionic liquid (IL) and STEM observation using the cooling holder eliminates the need for specialized equipment and techniques for biological sample preparation. The annular dark-field STEM results indicated that the two types of biodegradable poly-(DL-lactide-co-glycolide) (PLGA) NPs: PLGA modified with chitosan (CS), and clarithromycin (CAM)-loaded + CS-modified PLGA, prepared by emulsion solvent diffusion exhibited different antibacterial activities in nanoscale. To confirm damage to the sample during STEM observation, we observed the PLGA NPs and the biofilm treated with PLGA NPs by both the conventional method and the newly developed method. The optimized method allows microstructure of the biofilm treated with PLGA NPs to be maintained for 25 min at a current flow of 40 pA. The developed simple sample preparation method would be helpful to understand the interaction of drugs with target materials. In addition, this technique could contribute to the visualization of other deformable composite materials at the nanoscale level. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1432-1437, 2017.}, } @article {pmid27086424, year = {2016}, author = {Sukkua, K and Rattanachuay, P and Sukhumungoon, P}, title = {EX VIVO ADHERENCE TO MURINE ILEAL, BIOFILM FORMATION ABILITY AND PRESENCE OF ADHERENCE-ASSOCIATED OF HUMAN AND ANIMAL DIARRHEAGENIC ESCHERICHIA COLI.}, journal = {The Southeast Asian journal of tropical medicine and public health}, volume = {47}, number = {1}, pages = {40-54}, pmid = {27086424}, issn = {0125-1562}, mesh = {Animals ; Bacterial Adhesion/*physiology ; *Biofilms ; Diarrhea/*microbiology ; Escherichia coli/*physiology ; Escherichia coli Infections/*microbiology ; Escherichia coli Proteins/*physiology ; Humans ; Mice ; }, abstract = {Diarrheagenic Escherichia coli (DEC) are important bacteria causing gastrointestinal infection, which can lead to severe forms of illnesses. This study focused on DEC adherent capabilities using murine intestinal tissue as a model. Ex vivo adherence results showed that enteroaggregative E. coli (EAEC) strain PSU280 exhibited the highest level of adherence, followed by strains from ETEC category. Scanning electron micrographs displayed tight binding and putative bacterial curli fibers, including putative fimbrial structures. The presence of putative curli fibers was confirmed by the presence of csgA, a curli major structural subunit gene. Five and 3 of 15 DEC possessed lpf (encoding long polar fimbriae) and agn43 (encoding antigen43), respectively. Comparable biofilm formation efficiency but variable levels autoaggregation were observed among the DEC strains. In addition, yeast agglutination could be visualized in 11/15 strains. This study demonstrates the adherent ability of DEC strains isolated in southern Thailand as well as a number of crucial adherence-associated genes, information of importance to the understanding of DEC pathogenesis in this region of the country.}, } @article {pmid27086137, year = {2016}, author = {Shen, Y and Zhu, W and Chen, C and Nie, Y and Lin, X}, title = {Biofilm formation in attached microalgal reactors.}, journal = {Bioprocess and biosystems engineering}, volume = {39}, number = {8}, pages = {1281-1288}, doi = {10.1007/s00449-016-1606-9}, pmid = {27086137}, issn = {1615-7605}, mesh = {*Biofilms ; *Bioreactors ; Microalgae/*metabolism ; Nitrogen/metabolism ; }, abstract = {The objective of this study was to investigate the fundamental question of biofilm formation. First, a drum biofilm reactor was introduced. The drums were coated with three porous substrates (cotton rope, canvas, and spandex), respectively. The relationships among the substrate, extracellular polymeric substances (EPS), and adhesion ratio were analyzed. Second, a plate biofilm reactor (PBR) was applied by replacing the drum with multiple parallel vertical plates to increase the surface area. The plates were coated with porous substrates on each side, and the nutrients were delivered to the cells by diffusion. The influence of nitrogen source and concentration on compositions of EPS and biofilm formation was analyzed using PBR under sunlight. The results indicated that both substrate and nitrogen were critical on the EPS compositions and biofilm formation. Under the optimal condition (glycine with concentration of 1 g l(-1) and substrate of canvas), the maximum biofilm productivity of 54.46 g m(-2) d(-1) with adhesion ratio of 84.4 % was achieved.}, } @article {pmid27085154, year = {2016}, author = {Revilla, M and Galán, B and Viguri, JR}, title = {An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.}, journal = {Water research}, volume = {98}, number = {}, pages = {84-97}, doi = {10.1016/j.watres.2016.04.003}, pmid = {27085154}, issn = {1879-2448}, mesh = {*Biofilms ; *Biological Oxygen Demand Analysis ; Bioreactors ; Hydrolysis ; Models, Theoretical ; Waste Disposal, Fluid ; }, abstract = {An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions.}, } @article {pmid27085034, year = {2016}, author = {Amador, CI and López-Sánchez, A and Govantes, F and Santero, E and Canosa, I}, title = {A Pseudomonas putida cbrB transposon insertion mutant displays a biofilm hyperproducing phenotype that is resistant to dispersal.}, journal = {Environmental microbiology reports}, volume = {8}, number = {5}, pages = {622-629}, doi = {10.1111/1758-2229.12414}, pmid = {27085034}, issn = {1758-2229}, abstract = {The CbrAB two-component system in the Pseudomonads controls a variety of metabolic and behavioural traits required for its adaptation to changing environmental conditions, including the uptake or assimilation of certain carbon sources, and processes such as chemotaxis or stress tolerance. In this work we characterize a miniTn5-luxAB-Km transposon insertion mutant in cbrB (MPO406) in Pseudomonas putida leading to a biofilm overproducing phenotype that is not dispersed when nutrients are depleted. Comparison with a cbrB deletion mutant revealed that all phenotypes previously attributed to CbrB in P. putida correlated in both strains, with the exception of biofilm overproduction and absence of dispersal. We show that in the insertion mutant, the expression of the downstream regulatory RNA CrcZ is upregulated, and also show the presence of a truncated form of CbrB. Also, two additional point mutations in lapG and lapD have been detected in MPO406 by whole genome sequencing. Combination of these effects provides a robust biofilm overproducing phenotype. We present the mutant strain MPO406 as a good candidate to perform bio-production of substances of biotechnological interest or other processes such as bioremediation, which take advantage of immobilized cells on solid surfaces.}, } @article {pmid27083533, year = {2016}, author = {Donné, J and Van Kerckhoven, M and Maes, L and Cos, P and Dewilde, S}, title = {The role of the globin-coupled sensor YddV in a mature E. coli biofilm population.}, journal = {Biochimica et biophysica acta}, volume = {1864}, number = {7}, pages = {835-839}, doi = {10.1016/j.bbapap.2016.04.005}, pmid = {27083533}, issn = {0006-3002}, mesh = {*Biofilms ; Cyclic GMP/analogs & derivatives/biosynthesis ; Escherichia coli/*physiology ; Escherichia coli Proteins/*physiology ; Phosphorus-Oxygen Lyases/*physiology ; }, abstract = {Biofilm-associated infections are hard to treat because of their high antibiotic resistance and the presence of a very persistent subpopulation of bacteria. The second messenger molecule cyclic di-guanosine monophosphate (c-di-GMP) plays a very important role in this biofilm physiology. Here, we evaluated the role of YddV, an enzyme with a c-di-GMP synthesis function, in the formation and maturation of Escherichia coli biofilms. Our results suggest that YddV stimulates biofilm growth via its role in the production of c-di-GMP and this likely by influencing the production of matrix (e.g. poly-N-acetylglucosamine (PGA)). However, lowering the YddV expression did not alter the biofilm formation since there was no significant difference between the biofilm phenotypes of WT E. coli and YddV-knockout bacteria. Additionally, YddV expression had no significant influence on the amount of persister cells within the biofilm population, questioning the use of YddV as therapeutic target.}, } @article {pmid27081913, year = {2016}, author = {Melo, MA and Orrego, S and Weir, MD and Xu, HH and Arola, DD}, title = {Designing Multiagent Dental Materials for Enhanced Resistance to Biofilm Damage at the Bonded Interface.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {18}, pages = {11779-11787}, doi = {10.1021/acsami.6b01923}, pmid = {27081913}, issn = {1944-8252}, support = {R01 DE016904/DE/NIDCR NIH HHS/United States ; R01 DE017974/DE/NIDCR NIH HHS/United States ; }, mesh = {*Biofilms ; Composite Resins ; Dental Caries ; Dental Materials ; Humans ; Lactic Acid ; Materials Testing ; Prospective Studies ; }, abstract = {The oral environment is considered to be an asperous environment for restored tooth structure. Recurrent dental caries is a common cause of failure of tooth-colored restorations. Bacterial acids, microleakage, and cyclic stresses can lead to deterioration of the polymeric resin-tooth bonded interface. Research on the incorporation of cutting-edge anticaries agents for the design of new, long-lasting, bioactive resin-based dental materials is demanding and provoking work. Released antibacterial agents such as silver nanoparticles (NAg), nonreleased antibacterial macromolecules (DMAHDM, dimethylaminohexadecyl methacrylate), and released acid neutralizer amorphous calcium phosphate nanoparticles (NACP) have shown potential as individual and dual anticaries approaches. In this study, these agents were synthesized, and a prospective combination was incorporated into all the dental materials required to perform a composite restoration: dental primer, adhesive, and composite. We focused on combining different dental materials loaded with multiagents to improve the durability of the complex dental bonding interface. A combined effect of bacterial acid attack and fatigue on the bonding interface simulated the harsh oral environment. Human saliva-derived oral biofilm was grown on each sample prior to the cyclic loading. The oral biofilm viability during the fatigue performance was monitored by the live-dead assay. Damage of the samples that developed during the test was quantified from the fatigue life distributions. Results indicate that the resultant multiagent dental composite materials were able to reduce the acidic impact of the oral biofilm, thereby improving the strength and resistance to fatigue failure of the dentin-resin bonded interface. In summary, this study shows that dental restorative materials containing multiple therapeutic agents of different chemical characteristics can be beneficial toward improving resistance to mechanical and acidic challenges in oral environments.}, } @article {pmid27080421, year = {2016}, author = {He, Z and Liang, J and Zhou, W and Xie, Q and Tang, Z and Ma, R and Huang, Z}, title = {Effect of the quorum-sensing luxS gene on biofilm formation by Enterococcus faecalis.}, journal = {European journal of oral sciences}, volume = {124}, number = {3}, pages = {234-240}, doi = {10.1111/eos.12269}, pmid = {27080421}, issn = {1600-0722}, mesh = {Bacterial Proteins ; *Biofilms ; Carbon-Sulfur Lyases ; *Enterococcus faecalis ; *Quorum Sensing ; }, abstract = {Enterococcus faecalis is the species of bacterium most frequently isolated from the root canals of teeth that exhibit chronic apical periodontitis refractory to endodontic treatment. In this study, we evaluated the effect of the S-ribosylhomocysteine lyase (luxS) quorum-sensing gene on E. faecalis biofilm formation by constructing a knockout mutant. The biofilms formed by both E. faecalis and its luxS mutant strain were evaluated using the MTT method. Important parameters that influence biofilm formation, including cell-surface hydrophobicity and the nutrient content of the growth medium, were also studied. Biofilm structures were observed using confocal laser scanning microscopy (CLSM), and expression of biofilm-related genes was investigated using RT-PCR. The results showed that the luxS gene can affect biofilm formation, whereas it does not affect the bacterial growth rate. Deletion of the luxS gene also increased cell-surface hydrophobicity. Biofilm formation was accelerated by the addition of increasing concentrations of glucose. The CLSM images revealed that the luxS mutant strain tends to aggregate into distinct clusters and relatively dense structures, whereas the wild-type strain appears confluent and more evenly distributed. All genes examined were up-regulated in the biofilms formed by the luxS mutant strain. The quorum-sensing luxS gene can affect E. faecalis biofilm formation.}, } @article {pmid27079435, year = {2016}, author = {Crawford, EC and Singh, A and Gibson, TW and Scott Weese, J}, title = {Biofilm-Associated Gene Expression in Staphylococcus pseudintermedius on a Variety of Implant Materials.}, journal = {Veterinary surgery : VS}, volume = {45}, number = {4}, pages = {499-506}, doi = {10.1111/vsu.12471}, pmid = {27079435}, issn = {1532-950X}, mesh = {Animals ; Biofilms ; Gene Expression Regulation, Bacterial ; *Methicillin Resistance ; Polymerase Chain Reaction/veterinary ; Polymethyl Methacrylate ; Prostheses and Implants/*microbiology ; Stainless Steel ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus intermedius/genetics/*isolation & purification ; }, abstract = {OBJECTIVE: To evaluate the expression of biofilm-associated genes in Staphylococcus pseudintermedius on multiple clinically relevant surfaces.

STUDY DESIGN: In vitro experimental study.

SAMPLE POPULATION: Two strains of methicillin-resistant S. pseudintermedius isolated from clinical infections representing the most common international isolates.

METHODS: A quantitative polymerase chain reaction (qPCR) assay for expression of genes related to biofilm initial adhesion, formation/maturation, antimicrobial resistance, and intracellular communication was developed and validated. S. pseudintermedius biofilms were grown on 8 clinically relevant surfaces (polymethylmethacrylate, stainless steel, titanium, latex, silicone, polydioxanone, polystyrene, and glass) and samples of logarithmic and stationary growth phases were collected. Gene expression in samples was measured by qPCR.

RESULTS: Significant differences in gene expression were identified between surfaces and between bacterial strains for most gene/strain/surface combinations studied. Expression of genes responsible for production of extracellular matrix were increased in biofilms. Expression of genes responsible for initial adhesion and intracellular communication was markedly variable. Antimicrobial resistance gene expression was increased on multiple surfaces, including stainless steel and titanium.

CONCLUSION: A method for evaluation of expression of multiple biofilm-associated genes in S. pseudintermedius was successfully developed and applied to the study of biofilms on multiple surfaces. Variations in expression of these genes have a bearing on understanding the development and treatment of implant-associated biofilm infections and will inform future clinical research.}, } @article {pmid27073873, year = {2016}, author = {Fernández, CE and Fontana, M and Samarian, D and Cury, JA and Rickard, AH and González-Cabezas, C}, title = {Effect of Fluoride-Containing Toothpastes on Enamel Demineralization and Streptococcus mutans Biofilm Architecture.}, journal = {Caries research}, volume = {50}, number = {2}, pages = {151-158}, doi = {10.1159/000444888}, pmid = {27073873}, issn = {1421-976X}, mesh = {Animals ; Biofilms/*drug effects/growth & development ; Cattle ; Chlorhexidine/pharmacology ; Dental Enamel/*drug effects/microbiology/pathology ; Dose-Response Relationship, Drug ; Hydrogen-Ion Concentration ; Imaging, Three-Dimensional ; In Vitro Techniques ; Microscopy, Confocal ; Saliva/metabolism ; Sodium Fluoride/administration & dosage/*pharmacology ; Streptococcus mutans/*drug effects/growth & development ; Tin Fluorides/administration & dosage/*pharmacology ; Tooth Demineralization/*drug therapy/microbiology/prevention & control ; Toothpastes/administration & dosage/*pharmacology ; }, abstract = {This study aimed to explore the effect of fluoridated toothpastes on biofilm architecture and enamel demineralization in an in vitro biofilm model. Streptococcus mutans was grown on enamel and treated with slurries of commercial toothpastes, containing SnF2 or NaF. Water and chlorhexidine were used as negative and positive controls, respectively. The developed biofilms were imaged and enamel demineralization was measured. SnF2 and NaF toothpaste treatments significantly reduced enamel demineralization, but SnF2 toothpaste was more effective. Only SnF2 toothpaste and chlorhexidine treatments caused reductions on biofilm mass and thickness. In conclusion, this biofilm model was able to differentiate the effects of the SnF2 and NaF toothpastes on biofilm architecture and enamel demineralization.}, } @article {pmid27073807, year = {2016}, author = {Ruiz-Ruigomez, M and Badiola, J and Schmidt-Malan, SM and Greenwood-Quaintance, K and Karau, MJ and Brinkman, CL and Mandrekar, JN and Patel, R}, title = {Direct Electrical Current Reduces Bacterial and Yeast Biofilm Formation.}, journal = {International journal of bacteriology}, volume = {2016}, number = {}, pages = {9727810}, pmid = {27073807}, issn = {2356-6957}, support = {R01 AI091594/AI/NIAID NIH HHS/United States ; T32 AR056950/AR/NIAMS NIH HHS/United States ; }, abstract = {New strategies are needed for prevention of biofilm formation. We have previously shown that 24 hr of 2,000 µA of direct current (DC) reduces Staphylococcus epidermidis biofilm formation in vitro. Herein, we examined the effect of a lower amount of DC exposure on S. epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Propionibacterium acnes, and Candida albicans biofilm formation. 12 hr of 500 µA DC decreased S. epidermidis, S. aureus, E. coli, and P. aeruginosa biofilm formation on Teflon discs by 2, 1, 1, and 2 log10 cfu/cm(2), respectively (p < 0.05). Reductions in S. epidermidis, S. aureus, and E. coli biofilm formation were observed with as few as 12 hr of 200 µA DC (2, 2 and 0.4 log10 cfu/cm(2), resp.); a 1 log10 cfu/cm(2) reduction in P. aeruginosa biofilm formation was observed at 36 hr. 24 hr of 500 µA DC decreased C. albicans biofilm formation on Teflon discs by 2 log10 cfu/cm(2). No reduction in P. acnes biofilm formation was observed. 1 and 2 log10 cfu/cm(2) reductions in E. coli and S. epidermidis biofilm formation on titanium discs, respectively, were observed with 12 hr of exposure to 500 µA. Electrical current is a potential strategy to reduce biofilm formation on medical biomaterials.}, } @article {pmid27071334, year = {2016}, author = {Sugnaux, M and Fischer, F}, title = {Biofilm vivacity and destruction on antimicrobial nanosurfaces assayed within a microbial fuel cell.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {12}, number = {6}, pages = {1471-1477}, doi = {10.1016/j.nano.2016.03.008}, pmid = {27071334}, issn = {1549-9642}, mesh = {Anti-Bacterial Agents ; Anti-Infective Agents ; Bioelectric Energy Sources/*microbiology ; *Biofilms ; Escherichia coli ; }, abstract = {A novel method was developed to assay the antimicrobial capacity of nanostructured surfaces for medical implants in a bicathodic microbial fuel cell. Nano-structured gold surfaces with protruding nanopillars and nanorings were investigated. Escherichia coli K12 were used as a model microbe to record electronic effects caused by the interaction with nanosurfaces. The nanostructured gold surfaces enabled power density maxima up to 1910mW/m(2), indicating fair vivacity, while flat surfaces on the nanoscale provided almost no power 0.35mW/m(2). The biofilm presence on antimicrobial nanosurfaces was confirmed by the addition of ampicillin and its bactericidal effect resulted in oscillating and declining potentiometric signals. Current density experiments showed that biofilms on antimicrobial nanostructured electrodes caused low currents, indicating that E.coli biofilm remained functional before destruction. The bicathodic microbial fuel cell sensor is a novel tool for evaluating antimicrobial effects caused by nanosurfaces and antibiotics.}, } @article {pmid27069314, year = {2016}, author = {Feng, L and Xiang, Q and Ai, Q and Wang, Z and Zhang, Y and Lu, Q}, title = {Effects of Quorum Sensing Systems on Regulatory T Cells in Catheter-Related Pseudomonas aeruginosa Biofilm Infection Rat Models.}, journal = {Mediators of inflammation}, volume = {2016}, number = {}, pages = {4012912}, pmid = {27069314}, issn = {1466-1861}, mesh = {Animals ; Biofilms/*growth & development ; Female ; Forkhead Transcription Factors/metabolism ; Interleukin-10/metabolism ; Pseudomonas aeruginosa/*pathogenicity ; Quorum Sensing/*physiology ; Rats ; T-Lymphocytes, Regulatory/*metabolism ; Transforming Growth Factor beta1/metabolism ; }, abstract = {BACKGROUND: Quorum sensing (QS) systems play an important role in modulating biofilm formation. Recent studies have found that the QS molecules had complex effects on the host immune systems. In addition, regulatory T cells (Tregs), known as important negative regulators in the immune system, have been found upregulated in multiple chronic infections. Therefore, the QS systems were hypothesized to be involved in modulating Tregs in biofilm-associated infections. Object. To explore the effects of QS systems on Tregs in catheter-related Pseudomonas aeruginosa biofilm infection rat models.

METHOD: Catheter-related Pseudomonas aeruginosa biofilm infection rat models were established; the bacterial clearance rates, total cell counts in bronchoalveolar lavage (BAL) fluid, pathological changes of lungs, and the levels of Foxp3, TGF-β1, and IL-10 in PAO1 strain group were examined and compared with the QS-mutant ΔlasRΔrhlR and ΔlasIΔrhlI groups.

RESULTS: In PAO1 group, the bacterial clearance rates were lower, total cell counts were higher, pathological changes were severer, and the levels of Foxp3, TGF-β1, and IL-10 were significantly higher compared with QS-mutant groups (p < 0.05). No significant difference was observed between the two QS-mutant groups (p > 0.05).

CONCLUSION: QS systems can trigger host immune system, accompanied with the upregulation of Tregs.}, } @article {pmid27068911, year = {2016}, author = {Zhu, S and Shen, J and Ruan, Y and Guo, X and Ye, Z and Deng, Y and Shi, M}, title = {The effects of different seeding ratios on nitrification performance and biofilm formation in marine recirculating aquaculture system biofilter.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {14}, pages = {14540-14548}, pmid = {27068911}, issn = {1614-7499}, mesh = {*Aquaculture/methods ; *Bacteria ; *Bacterial Physiological Phenomena ; *Biofilms ; *Bioreactors ; Nitrification ; }, abstract = {Rapid start-up of biofilter is essential for intensive marine recirculating aquaculture system (RAS) production. This study evaluated the nitrifying biofilm formation using mature biofilm as an inoculum to accelerate the process in RAS practice. The effects of inoculation ratios (0-15 %) on the reactor performance and biofilm structure were investigated. Complete nitrification was achieved rapidly in reactors with inoculated mature biofilm (even in 32 days when 15 % seeding ratio was applied). However, the growth of target biofilm on blank carrier was affected by the mature biofilm inoculated through substrate competition. The analysis of extracellular polymeric substance (EPS) and nitrification rates confirmed the divergence of biofilm cultivation among reactors. Besides, three N-acyl-homoserine lactones (AHLs) were found in the process, which might regulate the activities of biofilm. Multivariate analysis based on non-metric multidimensional scaling (nMDS) also indicated the great roles of AHLs and substrate supply which might fundamentally determine varied cultivation performance on target biofilm.}, } @article {pmid27068594, year = {2016}, author = {Tseng, BS and Majerczyk, CD and Passos da Silva, D and Chandler, JR and Greenberg, EP and Parsek, MR}, title = {Quorum Sensing Influences Burkholderia thailandensis Biofilm Development and Matrix Production.}, journal = {Journal of bacteriology}, volume = {198}, number = {19}, pages = {2643-2650}, pmid = {27068594}, issn = {1098-5530}, support = {P20 GM103638/GM/NIGMS NIH HHS/United States ; R01 AI077628/AI/NIAID NIH HHS/United States ; R01 GM059026/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Burkholderia/*physiology ; Fucose/chemistry ; Gene Expression Regulation, Bacterial/physiology ; Polysaccharides, Bacterial/chemistry ; Quorum Sensing/*physiology ; }, abstract = {UNLABELLED: Members of the genus Burkholderia are known to be adept at biofilm formation, which presumably assists in the survival of these organisms in the environment and the host. Biofilm formation has been linked to quorum sensing (QS) in several bacterial species. In this study, we characterized Burkholderia thailandensis biofilm development under flow conditions and sought to determine whether QS contributes to this process. B. thailandensis biofilm formation exhibited an unusual pattern: the cells formed small aggregates and then proceeded to produce mature biofilms characterized by "dome" structures filled with biofilm matrix material. We showed that this process was dependent on QS. B. thailandensis has three acyl-homoserine lactone (AHL) QS systems (QS-1, QS-2, and QS-3). An AHL-negative strain produced biofilms consisting of cell aggregates but lacking the matrix-filled dome structures. This phenotype was rescued via exogenous addition of the three AHL signals. Of the three B. thailandensis QS systems, we show that QS-1 is required for proper biofilm development, since a btaR1 mutant, which is defective in QS-1 regulation, forms biofilms without these dome structures. Furthermore, our data show that the wild-type biofilm biomass, as well as the material inside the domes, stains with a fucose-binding lectin. The btaR1 mutant biofilms, however, are negative for fucose staining. This suggests that the QS-1 system regulates the production of a fucose-containing exopolysaccharide in wild-type biofilms. Finally, we present data showing that QS ability during biofilm development produces a biofilm that is resistant to dispersion under stress conditions.

IMPORTANCE: The saprophyte Burkholderia thailandensis is a close relative of the pathogenic bacterium Burkholderia pseudomallei, the causative agent of melioidosis, which is contracted from its environmental reservoir. Since most bacteria in the environment reside in biofilms, B. thailandensis is an ideal model organism for investigating questions in Burkholderia physiology. In this study, we characterized B. thailandensis biofilm development and sought to determine if quorum sensing (QS) contributes to this process. Our work shows that B. thailandensis produces biofilms with unusual dome structures under flow conditions. Our findings suggest that these dome structures are filled with a QS-regulated, fucose-containing exopolysaccharide that may be involved in the resilience of B. thailandensis biofilms against changes in the nutritional environment.}, } @article {pmid27068413, year = {2016}, author = {Mlynáriková, K and Šedo, O and Růžička, F and Zdráhal, Z and Holá, V and Mahelová, M}, title = {Evaluation of capacity to detect ability to form biofilm in Candida parapsilosis sensu stricto strains by MALDI-TOF MS.}, journal = {Folia microbiologica}, volume = {61}, number = {6}, pages = {465-471}, pmid = {27068413}, issn = {1874-9356}, mesh = {Biofilms/*growth & development ; Candida/*chemistry/*physiology ; Humans ; Microbiological Techniques/*methods ; Reproducibility of Results ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/*methods ; }, abstract = {Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is, currently, used as a rapid and reliable tool in microbial diagnostics. The discriminatory power of the method extends its applicability also beyond species level. This study examined the possibility to use MALDI-TOF MS to differentiate between Candida parapsilosis sensu stricto biofilm-positive (n = 12) and biofilm-negative (n = 9) strains. The results indicated a grouping trend within MALDI-TOF mass spectra belonging to each of the tested groups. However, these trends were eclipsed by mass spectral variations resulting from limited repeatability of the method, making its application for the selected purpose impossible. Improvement in the discriminatory power of the method was not obtained neither by using different matrices (α-cyano-4-hydroxycinnamic acid, ferulic acid, 5-chloro-2-mercaptobenzothionazole) for MALDI-TOF MS analysis nor by testing different culture conditions (cultivation length, culture media).}, } @article {pmid27068096, year = {2016}, author = {Ibberson, CB and Parlet, CP and Kwiecinski, J and Crosby, HA and Meyerholz, DK and Horswill, AR}, title = {Hyaluronan Modulation Impacts Staphylococcus aureus Biofilm Infection.}, journal = {Infection and immunity}, volume = {84}, number = {6}, pages = {1917-1929}, pmid = {27068096}, issn = {1098-5522}, support = {P01 AI083211/AI/NIAID NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; T32 AI007343/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections ; *Gene Expression Regulation, Bacterial ; *Host-Pathogen Interactions ; Hyaluronic Acid/*metabolism/pharmacology ; Male ; Mice ; Mice, Inbred C57BL ; Mutation ; Polysaccharide-Lyases/deficiency/genetics/*immunology/pharmacology ; Signal Transduction ; Staphylococcal Infections/*immunology/microbiology ; Staphylococcus aureus/drug effects/genetics/*immunology/ultrastructure ; Synovial Fluid/chemistry ; Vascular Access Devices ; }, abstract = {Staphylococcus aureus is a leading cause of chronic biofilm infections. Hyaluronic acid (HA) is a large glycosaminoglycan abundant in mammalian tissues that has been shown to enhance biofilm formation in multiple Gram-positive pathogens. We observed that HA accumulated in an S. aureus biofilm infection using a murine implant-associated infection model and that HA levels increased in a mutant strain lacking hyaluronidase (HysA). S. aureus secretes HysA in order to cleave HA during infection. Through in vitro biofilm studies with HA, the hysA mutant was found to accumulate increased biofilm biomass compared to the wild type, and confocal microscopy showed that HA is incorporated into the biofilm matrix. Exogenous addition of purified HysA enzyme dispersed HA-containing biofilms, while catalytically inactive enzyme had no impact. Additionally, induction of hysA expression prevented biofilm formation and also dispersed an established biofilm in the presence of HA. These observations were corroborated in the implant model, where there was decreased dissemination from an hysA mutant biofilm infection compared to the S. aureus wild type. Histopathology demonstrated that infection with an hysA mutant caused significantly reduced distribution of tissue inflammation compared to wild-type infection. To extend these studies, the impact of HA and S. aureus HysA on biofilm-like aggregates found in joint infections was examined. We found that HA contributes to the formation of synovial fluid aggregates, and HysA can disrupt aggregate formation. Taken together, these studies demonstrate that HA is a relevant component of the S. aureus biofilm matrix and HysA is important for dissemination from a biofilm infection.}, } @article {pmid27067266, year = {2016}, author = {Sahlberg Bang, C and Kruse, R and Johansson, K and Persson, K}, title = {Carbon monoxide releasing molecule-2 (CORM-2) inhibits growth of multidrug-resistant uropathogenic Escherichia coli in biofilm and following host cell colonization.}, journal = {BMC microbiology}, volume = {16}, number = {}, pages = {64}, pmid = {27067266}, issn = {1471-2180}, mesh = {Bacterial Load/drug effects ; Biofilms/*drug effects ; Cell Line ; Drug Resistance, Multiple, Bacterial/*drug effects ; Epithelial Cells/drug effects ; Escherichia coli Infections/*microbiology ; Humans ; Microbial Sensitivity Tests ; Organometallic Compounds/*pharmacology ; Urinary Bladder/cytology ; Uropathogenic Escherichia coli/drug effects/isolation & purification/*physiology ; }, abstract = {BACKGROUND: Increased resistance to antimicrobial agents is a characteristic of many bacteria growing in biofilms on for example indwelling urinary catheters or in intracellular bacterial reservoirs. Biofilm-related infections caused by multidrug-resistant bacteria, such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, are a major challenge. The aim of this study was to investigate if a carbon monoxide-releasing molecule (CORM-2) has antibacterial effects against ESBL-producing uropathogenic E. coli (UPEC) in the biofilm mode of growth and following colonization of host bladder epithelial cells.

RESULTS: The effect of CORM-2 was examined on bacteria grown within an established biofilm (biofilm formed for 24 h on plastic surface) by a live/dead viability staining assay. CORM-2 (500 μM) exposure for 24 h killed approximately 60 % of the ESBL-producing UPEC isolate. A non-ESBL-producing UPEC isolate and the E. coli K-12 strain TG1 were also sensitive to CORM-2 exposure when grown in biofilms. The antibacterial effect of CORM-2 on planktonic bacteria was reduced and delayed in the stationary growth phase compared to the exponential growth phase. In human bladder epithelial cell colonization experiments, CORM-2 exposure for 4 h significantly reduced the bacterial counts of an ESBL-producing UPEC isolate.

CONCLUSION: This study shows that CORM-2 has antibacterial properties against multidrug-resistant UPEC under biofilm-like conditions and following host cell colonization, which motivate further studies of its therapeutic potential.}, } @article {pmid27065957, year = {2016}, author = {Wang, S and Yang, Y and Zhao, Y and Zhao, H and Bai, J and Chen, J and Zhou, Y and Wang, C and Li, Y}, title = {Sub-MIC Tylosin Inhibits Streptococcus suis Biofilm Formation and Results in Differential Protein Expression.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {384}, pmid = {27065957}, issn = {1664-302X}, abstract = {Streptococcus suis (S.suis) is an important zoonotic pathogen that causes severe diseases in humans and pigs. Biofilms of S. suis can induce persistent infections that are difficult to treat. In this study, the effect of tylosin on biofilm formation of S. suis was investigated. 1/2 minimal inhibitory concentration (MIC) and 1/4 MIC of tylosin were shown to inhibit S. suis biofilm formation in vitro. By using the iTRAQ strategy, we compared the protein expression profiles of S. suis grown with sub-MIC tylosin treatment and with no treatment. A total of 1501 proteins were identified by iTRAQ. Ninety-six differentially expressed proteins were identified (Ratio > ±1.5, p < 0.05). Several metabolism proteins (such as phosphoglycerate kinase) and surface proteins (such as ABC transporter proteins) were found to be involved in biofilm formation. Our results indicated that S. suis metabolic regulation, cell surface proteins, and virulence proteins appear to be of importance in biofilm growth with sub-MIC tylosin treatment. Thus, our data revealed the rough regulation of biofilm formation that may provide a foundation for future research into mechanisms and targets.}, } @article {pmid27064218, year = {2016}, author = {McDaniel, C and Su, S and Panmanee, W and Lau, GW and Browne, T and Cox, K and Paul, AT and Ko, SH and Mortensen, JE and Lam, JS and Muruve, DA and Hassett, DJ}, title = {A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {291}, pmid = {27064218}, issn = {1664-302X}, abstract = {Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.}, } @article {pmid27063301, year = {2016}, author = {Zhang, FH and Li, M and Wei, ZJ and Zhao, B}, title = {[The effect of a combined nanoparticulate/calcium hydroxide medication on the biofilm of Enterococcus faecalis in starvation phase].}, journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology}, volume = {25}, number = {1}, pages = {11-15}, pmid = {27063301}, issn = {1006-7248}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents ; Biofilms/*drug effects ; Calcium Hydroxide/*pharmacology ; Dental Pulp Cavity ; Enterococcus faecalis/*drug effects ; Humans ; *Metal Nanoparticles ; Root Canal Irrigants/*pharmacology ; Silver/*pharmacology ; Tooth Root ; }, abstract = {PURPOSE: To evaluate the efficacy of Ca(OH)2 with a silver nanoparticle suspension to eliminate the biofilm of Enterococcus faecalis (E. faecalis) in starvation phase.

METHODS: The biofilm models of E．faecalis in the starvation phase were built in vitro with 256 extracted human single-rooted teeth, and the methods of plate culture count and crystal violet biofilm assay were applied to determine the effect of the inhibition of different intracanal medicament (silver nanoparticle with calcium hydroxide, silver nanoparticle alone, calcium hydroxide alone) to the biofilm of E. faecalis in starvation phase at 1 and 7 days. The negative control group was treated with sterile water only. Statistical analysis was carried out with SPSS 13.0 software package.

RESULTS: The inhibitory effect of Ca（OH）2+nanosilver on the biofilms of E. faecalis was found more significant than that of silver nanoparticle alone and calcium hydroxide alone at 1 and 7 days, and silver nanoparticle alone was more effective than calcium hydroxide alone. No difference in antimicrobial properties was observed between the two time points in the Ca(OH)2+silver nanoparticle group and silver nanoparticle group, while higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day.

CONCLUSIONS: Silver nanoparticle with calcium hydroxide has an obvious inhibitory effect on the biofilm of E.faecalis in the starvation phase.}, } @article {pmid27063112, year = {2015}, author = {Zhang, DM and Liu, JB and Pan, YP and Pan, JY and Xu, QF}, title = {[The impact of S.gordonii on P. gingivalis on the form of biofilm].}, journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology}, volume = {24}, number = {6}, pages = {641-644}, pmid = {27063112}, issn = {1006-7248}, mesh = {*Biofilms ; Porphyromonas gingivalis/*physiology ; Streptococcus gordonii/*physiology ; }, abstract = {PURPOSE: To investigate the impact of S.gordonii on the ultrastructure of P. gingivalis biofilm and on the amount of P. gingivalis in biofilm.

METHODS: P. gingivalis and/or S.gordonii grew on the culture slides to form single P. gingivalis biofilm and heterotypic biofilm of P.gingivalis-S.gordonii. Then the ultrastructure of the 2 kinds of film were examined by scanning electron microscope, and the amount of P. gingivalis in the biofilm was detected by qPCR. Statistical analysis was performed using pair t test with SPSS 13.0 statistical package.

RESULTS: At 72 h, the amount of heterotypic biofilm was much more than that of the single P. gingivalis biofilm. Moreover, the structure of the heterotypic biofilm was more regular and with more pore space compared to the single P. gingivalis biofilm. Compared to single P. gingivalis biofilm, the amount of P. gingivalis in heterotypic biofilm was 5.4, 3.8 and 4.4 fold at 24, 48 and 72 h, respectively.

CONCLUSIONS: The growth of P. gingivalis was promoted by S. gordonii in the form of heterotypic biofilm compared to single P. gingivalis biofilm.}, } @article {pmid27061804, year = {2016}, author = {DeForest, JL and Drerup, SA and Vis, ML}, title = {Using fatty acids to fingerprint biofilm communities: a means to quickly and accurately assess stream quality.}, journal = {Environmental monitoring and assessment}, volume = {188}, number = {5}, pages = {277}, pmid = {27061804}, issn = {1573-2959}, mesh = {Biofilms ; Biomass ; Ecosystem ; Environmental Monitoring/*methods ; Fatty Acids/*analysis ; Rivers/*chemistry ; Water Pollution/*analysis ; }, abstract = {The assessment of lotic ecosystem quality plays an essential role to help determine the extent of environmental stress and the effectiveness of restoration activities. Methods that incorporate biological properties are considered ideal because they provide direct assessment of the end goal of a vigorous biological community. Our primary objective was to use biofilm lipids to develop an accurate biomonitoring tool that requires little expertise and time to facilitate assessment. A model was created of fatty acid biomarkers most associated with predetermined stream quality classification, exceptional warm water habitat (EWH), warm water habitat (WWH), and limited resource (LR-AMD), and validated along a gradient of known stream qualities. The fatty acid fingerprint of the biofilm community was statistically different (P = 0.03) and was generally unique to recognized stream quality. One striking difference was essential fatty acids (DHA, EPA, and ARA) were absent from LR-AMD and only recovered from WWH and EWH, 45 % more in EWH than WWH. Independently testing the model along a stream quality gradient, this model correctly categorized six of the seven sites, with no match due to low sample biomass. These results provide compelling evidence that biofilm fatty acid analysis can be a sensitive, accurate, and cost-effective biomonitoring tool. We conceive of future studies expanding this research to more in-depth studies of remediation efforts, determining the applicable geographic area for the method and the addition of multiple stressors with the possibility of distinguishing among stressors.}, } @article {pmid27061781, year = {2016}, author = {Isaka, M and Tatsuno, I and Maeyama, J and Matsui, H and Zhang, Y and Hasegawa, T}, title = {The YvqE two-component system controls biofilm formation and acid production in Streptococcus pyogenes.}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {124}, number = {7}, pages = {574-585}, doi = {10.1111/apm.12538}, pmid = {27061781}, issn = {1600-0463}, mesh = {Biofilms/*growth & development ; Carboxylic Acids/*metabolism ; Cytosol/chemistry ; DNA Mutational Analysis ; Fimbriae, Bacterial/metabolism ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Histidine Kinase/genetics/*metabolism ; Hydrogen-Ion Concentration ; Mutagenesis, Site-Directed ; Mutant Proteins/genetics/metabolism ; Streptococcus pyogenes/*genetics/*physiology ; Virulence Factors/genetics/*metabolism ; }, abstract = {In Streptococcus pyogenes, proteins involved in determining virulence are controlled by stand-alone response regulators and by two-component regulatory systems. Previous studies reported that, compared to the parental strain, the yvqE sensor knockout strain showed significantly reduced growth and lower virulence. To determine the function of YvqE, we performed biofilm analysis and pH assays on yvqE mutants, and site-directed mutagenesis of YvqE. The yvqE deletion mutant showed a slower acid production rate, indicating that YvqE regulates acid production from sugar fermentation. The mutant strain, in which the Asp(26) residue in YvqE was replaced with Asn, affected biofilm formation, suggesting that this amino acid senses hydrogen ions produced by fermentative sugar metabolism. Signals received by YvqE were directly or indirectly responsible for inducing pilus expression. This study shows that at low environmental pH, biofilm formation in S. pyogenes is mediated by YvqE and suggests that regulation of pilus expression by environmental acidification could be directly under the control of YvqE.}, } @article {pmid27061393, year = {2016}, author = {Jäsberg, H and Söderling, E and Endo, A and Beighton, D and Haukioja, A}, title = {Bifidobacteria inhibit the growth of Porphyromonas gingivalis but not of Streptococcus mutans in an in vitro biofilm model.}, journal = {European journal of oral sciences}, volume = {124}, number = {3}, pages = {251-258}, doi = {10.1111/eos.12266}, pmid = {27061393}, issn = {1600-0722}, mesh = {Bifidobacterium/*physiology ; *Biofilms ; Fusobacterium nucleatum ; Gingiva/microbiology ; Humans ; Porphyromonas gingivalis/*growth & development ; Streptococcus mutans/*growth & development ; }, abstract = {There is growing interest in the use of probiotic bifidobacteria for enhancement of the therapy, and in the prevention, of oral microbial diseases. However, the results of clinical studies assessing the effects of bifidobacteria on the oral microbiota are controversial, and the mechanisms of actions of probiotics in the oral cavity remain largely unknown. In addition, very little is known about the role of commensal bifidobacteria in oral health. Our aim was to study the integration of the probiotic Bifidobacterium animalis subsp. lactis Bb12 and of oral Bifidobacterium dentium and Bifidobacterium longum isolates in supragingival and subgingival biofilm models and their effects on other bacteria in biofilms in vitro using two different in vitro biofilms and agar-overlay assays. All bifidobacteria integrated well into the subgingival biofilms composed of Porphyromonas gingivalis, Actinomyces naeslundii, and Fusobacterium nucleatum and decreased significantly only the number of P. gingivalis in the biofilms. The integration of bifidobacteria into the supragingival biofilms containing Streptococcus mutans and A. naeslundii was less efficient, and bifidobacteria did not affect the number of S. mutans in biofilms. Therefore, our results suggest that bifidobacteria may have a positive effect on subgingival biofilm and thereby potential in enhancing gingival health; however, their effect on supragingival biofilm may be limited.}, } @article {pmid27061262, year = {2016}, author = {Su, JF and Luo, XX and Wei, L and Ma, F and Zheng, SC and Shao, SC}, title = {Performance and microbial communities of Mn(II)-based autotrophic denitrification in a Moving Bed Biofilm Reactor (MBBR).}, journal = {Bioresource technology}, volume = {211}, number = {}, pages = {743-750}, doi = {10.1016/j.biortech.2016.03.101}, pmid = {27061262}, issn = {1873-2976}, mesh = {Autotrophic Processes ; *Biofilms ; Bioreactors/*microbiology ; Denitrification ; Nitrates/chemistry ; }, abstract = {In this study, Mn(II) as electron donor was tested for the effects on denitrification in the MBBR under the conditions of initial nitrate concentration (10mgL(-1), 30mgL(-1), 50mgL(-1)), pH (5, 6, 7) and hydraulic retention time (HRT) (4h, 8h, 12h) which conducted by response surface methodology (RSM), the results demonstrated that the highest nitrate removal efficiency was occurred under the conditions of initial nitrate concentration of 47.64mgL(-1), HRT of 11.96h and pH 5.21. Analysis of SEM and flow cytometry suggested that microorganisms were immobilized on the Yu Long plastic carrier media successfully before the reactor began to operate. Furthermore, high-throughput sequencing was employed to characterize and compare the community compositions and structures of MBBR under the optimum conditions, the results showed that Pseudomonas sp. SZF15 was the dominant contributor for effective removal of nitrate in the MBBR.}, } @article {pmid27060056, year = {2016}, author = {Volgenant, CM and Hoogenkamp, MA and Buijs, MJ and Zaura, E and Ten Cate, JM and van der Veen, MH}, title = {Red fluorescent biofilm: the thick, the old, and the cariogenic.}, journal = {Journal of oral microbiology}, volume = {8}, number = {}, pages = {30346}, pmid = {27060056}, issn = {2000-2297}, abstract = {BACKGROUND: Some dental plaque fluoresces red. The factors involved in this fluorescence are yet unknown.

OBJECTIVE: The aim of this study was to assess systematically the effect of age, thickness, and cariogenicity on the extent of red fluorescence produced by in vitro microcosm biofilms.

DESIGN: The effects of biofilm age and thickness on red fluorescence were tested in a constant depth film fermentor (CDFF) by growing biofilms of variable thicknesses that received a constant supply of defined mucin medium (DMM) and eight pulses of sucrose/day. The influence of cariogenicity on red fluorescence was tested by growing biofilm on dentin disks receiving DMM, supplemented with three or eight pulses of sucrose/day. The biofilms were analyzed at different time points after inoculation, up to 24 days. Emission spectra were measured using a fluorescence spectrophotometer (λexc405 nm) and the biofilms were photographed with a fluorescence camera. The composition of the biofilms was assessed using 454-pyrosequecing of the 16S rDNA gene.

RESULTS: From day 7 onward, the biofilms emitted increasing intensities of red fluorescence as evidenced by the combined red fluorescence peaks. The red fluorescence intensity correlated with biofilm thickness but not in a linear way. Biofilm fluorescence also correlated with the imposed cariogenicity, evidenced by the induced dentin mineral loss. Increasing the biofilm age or increasing the sucrose pulsing frequency led to a shift in the microbial composition. These shifts in composition were accompanied by an increase in red fluorescence.

CONCLUSIONS: The current study shows that a thicker, older, or more cariogenic biofilm results in a higher intensity of red fluorescence.}, } @article {pmid27059830, year = {2016}, author = {Wannemuehler, TJ and Lobo, BC and Johnson, JD and Deig, CR and Ting, JY and Gregory, RL}, title = {Vibratory stimulus reduces in vitro biofilm formation on tracheoesophageal voice prostheses.}, journal = {The Laryngoscope}, volume = {126}, number = {12}, pages = {2752-2757}, doi = {10.1002/lary.25969}, pmid = {27059830}, issn = {1531-4995}, mesh = {Biofilms/*growth & development ; Cross-Over Studies ; Humans ; In Vitro Techniques ; Larynx, Artificial/*microbiology ; Prospective Studies ; Prosthesis Design ; *Vibration ; }, abstract = {OBJECTIVES/HYPOTHESIS: Demonstrate that biofilm formation will be reduced on tracheoesophageal prostheses when vibratory stimulus is applied, compared to controls receiving no vibratory stimulus, in a dynamic in vitro model of biofilm accumulation simulating the interface across the tracheoesophageal puncture site.

STUDY DESIGN: Prospective, randomized, controlled, crossover in university laboratory.

METHODS: Ex vivo tracheoesophageal prostheses were obtained from university-affiliated speech language pathologists at Indiana University School of Medicine, Indianapolis. Prostheses demonstrating physical integrity and an absence of gross biofilm accumulation were utilized. Sixteen prostheses were cleansed and sterilized prior to random placement by length in two modified Robbins devices arranged in parallel. Each device was seeded with a polymicrobial oral flora on day 1 and received basal artificial salivary flow continuously with three growth medium meals daily. One device was randomly selected for vibratory stimulus, and 2 minutes of vibration was applied to each prosthesis before and after meals for 5 days. The prostheses were explanted and sonicated, and the biofilm cultured for enumeration. This process was repeated after study arm crossover.

RESULTS: Tracheoesophageal prostheses in the dynamic model receiving vibratory stimulus demonstrated reduced gross biofilm accumulation and a significant biofilm colony forming unit per milliliter reduction of 5.56-fold compared to nonvibratory controls (P < 0.001). Significant reductions were observed within length subgroups.

CONCLUSION: Application of vibratory stimulus around meal times significantly reduces biofilm accumulation on tracheoesophageal prostheses in a dynamic in vitro model. Further research using this vibratory stimulus method in vivo will be required to determine if reduced biofilm accumulation correlates with longer device lifespan.

LEVEL OF EVIDENCE: NA Laryngoscope, 126:2752-2757, 2016.}, } @article {pmid27058375, year = {2016}, author = {Souza, JC and Mota, RR and Sordi, MB and Passoni, BB and Benfatti, CA and Magini, RS}, title = {Biofilm Formation on Different Materials Used in Oral Rehabilitation.}, journal = {Brazilian dental journal}, volume = {27}, number = {2}, pages = {141-147}, doi = {10.1590/0103-6440201600625}, pmid = {27058375}, issn = {1806-4760}, mesh = {Biofilms ; *Dental Implants ; *Dental Materials ; Humans ; Microscopy, Electron, Scanning ; Saliva ; Spectrum Analysis/methods ; Surface Properties ; }, abstract = {The aim of this study was to evaluate the density and the morphological aspects of biofilms adhered to different materials applied in oral rehabilitation supported by dental implants. Sixty samples were divided into four groups: feldspar-based porcelain, CoCr alloy, commercially pure titanium grade IV and yttria-stabilized zirconia. Human saliva was diluted into BHI supplemented with sucrose to grow biofilms for 24 or 48 h. After this period, biofilm was removed by 1% protease treatment and then analyzed by spectrophotometry (absorbance), colony forming unit method (CFU.cm-2) and field-emission guns scanning electron microscopy (FEG-SEM). The highest values of absorbance and CFU.cm-2 were recorded on biofilms grown on CoCr alloys when compared to the other test materials for 24 or 48 h. Also, FEG-SEM images showed a high biofilm density on CoCr. There were no significant differences in absorbance and CFU.cm-2 between biofilms grown on zirconia, porcelain and titanium (p<0.05). Microbiological assays associated with microscopic analyses detected a higher accumulation of oral biofilms on CoCr-based materials than that on titanium or zirconia that are used for prosthetic structures.}, } @article {pmid27055427, year = {2016}, author = {Qu, D and Ren, XX and Guo, LY and Liang, JX and Xu, WJ and Han, YH and Zhu, YM}, title = {[Effect of N-acetylcysteine inhalation on ventilator-associated pneumonia caused by biofilm in endotracheal tubes].}, journal = {Zhonghua er ke za zhi = Chinese journal of pediatrics}, volume = {54}, number = {4}, pages = {278-282}, doi = {10.3760/cma.j.issn.0578-1310.2016.04.010}, pmid = {27055427}, issn = {0578-1310}, mesh = {Acetylcysteine/*administration & dosage ; Administration, Inhalation ; *Biofilms ; Gram-Negative Bacteria/pathogenicity ; Humans ; Incidence ; Intubation, Intratracheal ; Pneumonia, Ventilator-Associated/*drug therapy/*microbiology ; Respiration, Artificial/adverse effects ; }, abstract = {OBJECTIVE: To observe the formation of the biofilm in endotracheal tubes, the characteristics of etiology, drug resistance and effect on the biofilm and ventilator-associated pneumonia (VAP) of inhaled N-acetylcysteine (NAC).

METHOD: We selected 117 tracheally intubated and undergoing mechanical ventilation for ≥48 h in our hospital ICU from September 2010 to August 2012. All the cases were randomly divided into control group (60 cases) and study group (57 cases). The patients in the study group were treated with different doses of aerosolized NAC according to different ages, starting the first administration within 12 hours of mechanical ventilation, once every 8 hours, until stopping mechanical ventilation. Comparison was performed on the two groups in biofilm structure under the scanning electron microscopy, biofilm culture positive rate, VAP incidence, the etiology and drug resistance of the lower airway secretions and biofilms.

RESULT: (1) Electron microscopy showed that biofilm had formed in the endotracheal tube inner wall in early period of mechanical ventilation. With prolonged mechanical ventilation, biofilm structure improved. At the same time of mechanical ventilation, the thickness of biofilm in the study group decreased as compared with the control group. (2) Biofilm culture positive rate and incidence of ventilator-associated pneumonia decreased in the study group compared with in the control group (65%(37/57) vs. 80%(48/60), P<0.05; 11% (6/57)vs. 32%(19/60), P<0.01). (3) A large number of pathogenic bacteria colonized in the biofilm and gram-negative bacilli dominated. With prolonged mechanical ventilation, the cultured pathogens converged from the lower airway secretions and biofilm.

CONCLUSION: With prolonged mechanical ventilation, biofilm structure was improved. Inhalation of NAC can inhibit biofilm formation and reduce the incidence of VAP.}, } @article {pmid27054728, year = {2016}, author = {Ai, H and Xu, J and Huang, W and He, Q and Ni, B and Wang, Y}, title = {Mechanism and kinetics of biofilm growth process influenced by shear stress in sewers.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {7}, pages = {1572-1582}, doi = {10.2166/wst.2015.633}, pmid = {27054728}, issn = {0273-1223}, mesh = {Bacteria ; *Biofilms ; Bioreactors ; Kinetics ; Models, Theoretical ; Sanitary Engineering ; Stress, Mechanical ; Time Factors ; }, abstract = {Sewer biofilms play an important role in the biotransformation of substances for methane and sulfide emission in sewer networks. The dynamic flows and the particular shear stress in sewers are the key factors determining the growth of the sewer biofilm. In this work, the development of sewer biofilm with varying shear stress is specifically investigated to gain a comprehensive understanding of the sewer biofilm dynamics. Sewer biofilms were cultivated in laboratory-scale gravity sewers under different hydraulic conditions with the corresponding shell stresses are 1.12 Pa, 1.29 Pa and 1.45 Pa, respectively. The evolution of the biofilm thickness were monitored using microelectrodes, and the variation in total solids (TS) and extracellular polymer substance (EPS) levels in the biofilm were also measured. The results showed that the steady-state biofilm thickness were highly related to the corresponding shear stresses with the biofilm thickness of 2.4 ± 0.1 mm, 2.7 ± 0.1 mm and 2.2 ± 0.1 mm at shear stresses of 1.12 Pa, 1.29 Pa and 1.45 Pa, respectively, which the chemical oxygen demand concentration is 400 mg/L approximately. Based on these observations, a kinetic model for describing the development of sewer biofilms was developed and demonstrated to be capable of reproducing all the experimental data.}, } @article {pmid27054722, year = {2016}, author = {Gani, KM and Singh, J and Singh, NK and Ali, M and Rose, V and Kazmi, AA}, title = {Nitrogen and carbon removal efficiency of a polyvinyl alcohol gel based moving bed biofilm reactor system.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {7}, pages = {1511-1519}, doi = {10.2166/wst.2015.631}, pmid = {27054722}, issn = {0273-1223}, mesh = {Ammonium Compounds ; Bacteria/metabolism ; *Biofilms ; Biological Oxygen Demand Analysis ; Biomass ; *Bioreactors ; Carbon/chemistry/*metabolism ; Nitrogen/chemistry/*metabolism ; Phosphorus ; Polyvinyl Alcohol/*chemistry ; Sewage/chemistry ; Waste Disposal, Fluid/methods ; Wastewater ; Water Pollutants, Chemical ; }, abstract = {In this study, the effectiveness of polyvinyl alcohol (PVA) gel beads in treating domestic wastewater was investigated: a moving bed biofilm reactor (MBBR) configuration (oxic-anoxic and oxic) with 10% filling fraction of biomass carriers was operated in a continuously fed regime at temperatures of 25, 20, 15 and 6 °C with hydraulic retention times (HRTs) of 32 h, 18 h, 12 h and 9 h, respectively. Influent loadings were in the range of 0.22-1.22 kg N m(-3) d(-1) (total nitrogen (TN)), 1.48-7.82 kg chemical oxygen demand (COD) m(-3) d(-1) (organic) and 0.12-0.89 kg NH4(+)-N m(-3)d(-1) (ammonia nitrogen). MBBR performance resulted in the maximum TN removal rate of 1.22 kg N m(-3) d(-1) when the temperature and HRT were 6 °C and 9 h, respectively. The carbon removal rate at this temperature and HRT was 6.82 kg COD m(-3) d(-1). Ammonium removal rates ranged from 0.13 to 0.75 kg NH4(+)-N m(-3) d(-1) during the study. Total phosphorus and suspended solid removal efficiency ranged from 84 to 98% and 85 to 94% at an influent concentration of 3.3-7.1 mg/L and 74-356 mg/L, respectively. The sludge wasted from the MBBR exhibited light weight features characterized by sludge volume index value of 185 mL/g. Experimental data obtained can be useful in further developing the concept of PVA gel based wastewater treatment systems.}, } @article {pmid27052705, year = {2016}, author = {Carter, MQ and Louie, JW and Feng, D and Zhong, W and Brandl, MT}, title = {Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.}, journal = {Food microbiology}, volume = {57}, number = {}, pages = {81-89}, doi = {10.1016/j.fm.2016.01.006}, pmid = {27052705}, issn = {1095-9998}, mesh = {*Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Escherichia coli O157/genetics/*physiology ; Plant Leaves/microbiology ; Spinacia oleracea/*microbiology ; Stainless Steel/analysis ; }, abstract = {Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enhanced biofilm production on glass by 19-27 fold in LB no-salt broth. However, this contribution was not observed when cells were grown in sterile spinach lysates. Furthermore, both strains of E. coli O157:H7 produced minimal biofilms on polypropylene in LB no-salt broth but considerable amounts in spinach lysates. Under the latter conditions, curli appeared to slightly increase biofilm production. Importantly, curli played an essential role in the formation of mixed biofilm by E. coli O157:H7 and plant-associated microorganisms in spinach leaf washes, as revealed by confocal microscopy. Little or no E. coli O157:H7 biofilms were detected at 4 °C, supporting the importance of temperature control in postharvest and produce processing environments.}, } @article {pmid27052509, year = {2016}, author = {Leinweber, K and Müller, S and G Kroth, P}, title = {A semi-automated, KNIME-based workflow for biofilm assays.}, journal = {BMC microbiology}, volume = {16}, number = {}, pages = {61}, pmid = {27052509}, issn = {1471-2180}, mesh = {*Biofilms ; Computational Biology/*methods ; Diatoms/*growth & development ; High-Throughput Screening Assays ; Humans ; Software ; Water Microbiology ; Workflow ; }, abstract = {BACKGROUND: A current focus of biofilm research is the chemical interaction between microorganisms within the biofilms. Prerequisites for this research are bioassay systems which integrate reliable tools for the planning of experiments with robot-assisted measurements and with rapid data processing. Here, data structures that are both human- and machine readable may be particularly useful.

RESULTS: In this report, we present several simplification and robotisation options for an assay of bacteria-induced biofilm formation by the freshwater diatom Achnanthidium minutissimum. We also tested several proof-of-concept robotisation methods for pipetting, as well as for measuring the biofilm absorbance directly in the multi-well plates. Furthermore, we exemplify the implementation of an improved data processing workflow for this assay using the Konstanz Information Miner (KNIME), a free and open source data analysis environment. The workflow integrates experiment planning files and absorbance read-out data, towards their automated processing for analysis.

CONCLUSIONS: Our workflow lead to a substantial reduction of the measurement and data processing workload, while still reproducing previously obtained results in the A. minutissimum biofilm assay. The methods, scripts and files we designed are described here, offering adaptable options for other medium-throughput biofilm screenings.}, } @article {pmid27052335, year = {2016}, author = {Antony, S and Farran, Y}, title = {Prosthetic Joint and Orthopedic Device Related Infections. The Role of Biofilm in the Pathogenesis and Treatment.}, journal = {Infectious disorders drug targets}, volume = {16}, number = {1}, pages = {22-27}, doi = {10.2174/1871526516666160407113646}, pmid = {27052335}, issn = {2212-3989}, mesh = {Anti-Bacterial Agents/therapeutic use ; Bacterial Infections/diagnosis/drug therapy/*microbiology/therapy ; *Biofilms ; Humans ; Joint Prosthesis/*microbiology ; Methicillin-Resistant Staphylococcus aureus/pathogenicity ; Orthopedic Fixation Devices/adverse effects/*microbiology ; Prosthesis-Related Infections/diagnosis/drug therapy/*microbiology/*therapy ; }, abstract = {Prosthetic joint infections (PJI) in orthopedic related devices (ORD) are major issues following replacement of joints. It results in serious morbidity and mortality and is expensive to treat and manage. The pathogenesis of these infections is related to the presence of biofilm on the metallic and plastic surfaces of the devices. This biofilm results in poor penetration of antibiotics resulting in persistence and difficulty in eradication of the infection despite appropriate antibiotics. This paper summarizes the present data of biofilm as it relates to PJI/ORD.}, } @article {pmid27051945, year = {2015}, author = {Junling, W and Qiang, Z and Ruinan, S and Ting, Z and Jianhua, G and Chuanjian, Z}, title = {[Dental plaque microcosm biofilm behavior on a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt].}, journal = {Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology}, volume = {33}, number = {6}, pages = {565-569}, pmid = {27051945}, issn = {1000-1182}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Composite Resins/*chemistry ; Dental Caries/prevention & control ; *Dental Plaque ; Humans ; Lactic Acid ; Quaternary Ammonium Compounds/*pharmacology ; Saliva ; }, abstract = {OBJECTIVE: To develop a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt, and to measure its effect on human dental plaque microcosm biofilm.

METHODS: A novel nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt was synthesized according to methods introduced in previous research. Samples of the novel nano-antibacterial inorganic fillers were modified by a coupling agent and then added into resin composite at 0%, 5%, 10%, 15% or 20% mass fractions; 0% composite was used as control. A flexural test was used to measure resin composite mechanical properties. Results showed that a dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming unit (CFU) counts, lactic acid production, and live/dead assay of biofilm on the resin composite were calculated to test the effect of the resin composite on human dental plaque microcosm biofilm.

RESULTS: The incorporation of nano-antibacterial inorganic fillers with as much as 15% concentration into the resin composite showed no adverse effect on the mechanical properties of the resin composite (P > 0.05). Resin composite containing 5% or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilm, suggesting its strong antibacterial potency (P < 0.05).

CONCLUSION: This novel resin composite exhibited a strong antibacterial property upon the addition of up to 5% nano-antibacterial inorganic fillers, thereby leading to effective caries inhibition in dental application.}, } @article {pmid27051178, year = {2016}, author = {Abdullahi, UF and Igwenagu, E and Mu'azu, A and Aliyu, S and Umar, MI}, title = {Intrigues of biofilm: A perspective in veterinary medicine.}, journal = {Veterinary world}, volume = {9}, number = {1}, pages = {12-18}, pmid = {27051178}, issn = {0972-8988}, abstract = {Biofilm has a tremendous impact in the field of veterinary medicine, especially the livestock industry, leading to a serious economic loss. Over the years, little attention has been given to biofilm in animals with most of the research geared toward human biofilm diseases. The greatest challenge posed by biofilm is in its incredible ability to resist most of the currently existing antibiotics. This mystery can best be demystified through understanding the mechanism of the quorum sensing which regulate the pathophysiology of biofilm. Ability of biofilm formation in a variety of inanimate surfaces such as animal food contact surfaces is responsible for a host of biofilm diseases affecting animals and humans. In this review, we highlighted some of the challenges of biofilm in livestock and food industries. Also highlighted are; mechanisms of biofilm development, best diagnostic approach and possible novel therapeutic measures needed to combat the menace of biofilm in veterinary medicine.}, } @article {pmid27048799, year = {2016}, author = {Lee, MJ and Geller, AM and Bamford, NC and Liu, H and Gravelat, FN and Snarr, BD and Le Mauff, F and Chabot, J and Ralph, B and Ostapska, H and Lehoux, M and Cerone, RP and Baptista, SD and Vinogradov, E and Stajich, JE and Filler, SG and Howell, PL and Sheppard, DC}, title = {Deacetylation of Fungal Exopolysaccharide Mediates Adhesion and Biofilm Formation.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00252-16}, pmid = {27048799}, issn = {2150-7511}, support = {236182//Canadian Institutes of Health Research/Canada ; 81361//Canadian Institutes of Health Research/Canada ; R01AI073829/AI/NIAID NIH HHS/United States ; S10 OD016290/OD/NIH HHS/United States ; 13337//Canadian Institutes of Health Research/Canada ; R01 AI073829/AI/NIAID NIH HHS/United States ; }, mesh = {Acetylation ; Aspergillosis/*microbiology ; Aspergillus fumigatus/genetics/growth & development/*physiology ; *Biofilms ; Fungal Proteins/genetics/metabolism ; Humans ; Polysaccharides/*metabolism ; }, abstract = {UNLABELLED: The mold Aspergillus fumigatus causes invasive infection in immunocompromised patients. Recently, galactosaminogalactan (GAG), an exopolysaccharide composed of galactose and N-acetylgalactosamine (GalNAc), was identified as a virulence factor required for biofilm formation. The molecular mechanisms underlying GAG biosynthesis and GAG-mediated biofilm formation were unknown. We identified a cluster of five coregulated genes that were dysregulated in GAG-deficient mutants and whose gene products share functional similarity with proteins that mediate the synthesis of the bacterial biofilm exopolysaccharide poly-(β1-6)-N-acetyl-D-glucosamine (PNAG). Bioinformatic analyses suggested that the GAG cluster gene agd3 encodes a protein containing a deacetylase domain. Because deacetylation of N-acetylglucosamine residues is critical for the function of PNAG, we investigated the role of GAG deacetylation in fungal biofilm formation. Agd3 was found to mediate deacetylation of GalNAc residues within GAG and render the polysaccharide polycationic. As with PNAG, deacetylation is required for the adherence of GAG to hyphae and for biofilm formation. Growth of the Δagd3 mutant in the presence of culture supernatants of the GAG-deficient Δuge3 mutant rescued the biofilm defect of the Δagd3 mutant and restored the adhesive properties of GAG, suggesting that deacetylation is an extracellular process. The GAG biosynthetic gene cluster is present in the genomes of members of the Pezizomycotina subphylum of the Ascomycota including a number of plant-pathogenic fungi and a single basidiomycete species,Trichosporon asahii, likely a result of recent horizontal gene transfer. The current study demonstrates that the production of cationic, deacetylated exopolysaccharides is a strategy used by both fungi and bacteria for biofilm formation.

IMPORTANCE: This study sheds light on the biosynthetic pathways governing the synthesis of galactosaminogalactan (GAG), which plays a key role in A. fumigatus virulence and biofilm formation. We find that bacteria and fungi use similar strategies to synthesize adhesive biofilm exopolysaccharides. The presence of orthologs of the GAG biosynthetic gene clusters in multiple fungi suggests that this exopolysaccharide may also be important in the virulence of other fungal pathogens. Further, these studies establish a molecular mechanism of adhesion in which GAG interacts via charge-charge interactions to bind to both fungal hyphae and other substrates. Finally, the importance of deacetylation in the synthesis of functional GAG and the extracellular localization of this process suggest that inhibition of deacetylation may be an attractive target for the development of novel antifungal therapies.}, } @article {pmid27047457, year = {2016}, author = {Jamil, B and Habib, H and Abbasi, SA and Ihsan, A and Nasir, H and Imran, M}, title = {Development of Cefotaxime Impregnated Chitosan as Nano-antibiotics: De Novo Strategy to Combat Biofilm Forming Multi-drug Resistant Pathogens.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {330}, pmid = {27047457}, issn = {1664-302X}, abstract = {Frequent incidents of antibiotic-resistant biofilm forming pathogens in community-associated and hospital-acquired infections have become a global concern owing to failure of conventional therapies. Nano-antibiotics (NABs) are de novo tools to overcome the multi-drug resistant mechanisms employed by the superbugs. Inhibition of biofilm formation is one of those strategies to curb multi drug resistance phenomenon. In the current study, the anti-biofilm and antibacterial potential of newly synthesized cefotaxime loaded chitosan based NABs have been investigated. Both bare and cefotaxime loaded NABs were prepared by ionotropic gelation method. They were found carrying positive zeta potential of more than +50 mV, indicating highly stable nano-dispersion. Moreover, microscopic studies revealed their size as less than 100 nm. NABs were tested against clinical isolates of multi drug resistant Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and methicillin resistant Staphylococcus aureus and wherein they demonstrated broad-spectrum anti-biofilm and anti-pathogenic activity. Thus, in vitro synergistic action of cephalosporin drugs and chitosan polymer at nano-scale in contrast to free antibiotics can be an improved broad-spectrum strategy to thwart resistance mechanisms in both Gram-positive and Gram-negative resistant pathogens.}, } @article {pmid27045372, year = {2016}, author = {Lam, RH and Cui, X and Guo, W and Thorsen, T}, title = {High-throughput dental biofilm growth analysis for multiparametric microenvironmental biochemical conditions using microfluidics.}, journal = {Lab on a chip}, volume = {16}, number = {9}, pages = {1652-1662}, doi = {10.1039/c6lc00072j}, pmid = {27045372}, issn = {1473-0189}, mesh = {Actinomyces/growth & development/isolation & purification/physiology ; Automation, Laboratory ; Biofilms/*growth & development ; Dimethylpolysiloxanes/chemistry ; Equipment Design ; Fusobacterium nucleatum/growth & development/isolation & purification/*physiology ; High-Throughput Screening Assays/*instrumentation ; Humans ; Image Processing, Computer-Assisted ; *Lab-On-A-Chip Devices ; Microarray Analysis/instrumentation ; Microscopy, Fluorescence ; *Models, Biological ; Porphyromonas gingivalis/growth & development/isolation & purification/physiology ; Species Specificity ; Stereolithography ; Streptococcus/growth & development/isolation & purification/*physiology ; Surface Properties ; Time-Lapse Imaging ; Tooth/*chemistry/microbiology ; }, abstract = {Dental biofilm formation is not only a precursor to tooth decay, but also induces more serious systematic health problems such as cardiovascular disease and diabetes. Understanding the conditions promoting colonization and subsequent biofilm development involving complex bacteria coaggregation is particularly important. In this paper, we report a high-throughput microfluidic 'artificial teeth' device offering controls of multiple microenvironmental factors (e.g. nutrients, growth factors, dissolved gases, and seeded cell populations) for quantitative characteristics of long-term dental bacteria growth and biofilm development. This 'artificial teeth' device contains multiple (up to 128) incubation chambers to perform parallel cultivation and analyses (e.g. biofilm thickness, viable-dead cell ratio, and spatial distribution of multiple bacterial species) of bacteria samples under a matrix of different combinations of microenvironmental factors, further revealing possible developmental mechanisms of dental biofilms. Specifically, we applied the 'artificial teeth' to investigate the growth of two key dental bacteria, Streptococci species and Fusobacterium nucleatum, in the biofilm under different dissolved gas conditions and sucrose concentrations. Together, this high-throughput microfluidic platform can provide extended applications for general biofilm research, including screening of the biofilm properties developing under combinations of specified growth parameters such as seeding bacteria populations, growth medium compositions, medium flow rates and dissolved gas levels.}, } @article {pmid27045200, year = {2016}, author = {Sutrina, SL and Griffith, MSJ and Lafeuillee, C}, title = {2-Deoxy-d-glucose is a potent inhibitor of biofilm growth in Escherichia coli.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {6}, pages = {1037-1046}, doi = {10.1099/mic.0.000290}, pmid = {27045200}, issn = {1465-2080}, mesh = {Antimetabolites/*pharmacology ; Biofilms/*growth & development ; Cyclic AMP/pharmacology ; Deoxyglucose/*pharmacology ; Escherichia coli/drug effects/*growth & development ; Glucose-6-Phosphate/pharmacology ; Methylglucosides/pharmacology ; Methylmannosides/pharmacology ; }, abstract = {Escherichia coli strain 15 (ATCC 9723), which forms robust biofilms, was grown under optimal biofilm conditions in NaCl-free Luria-Bertani broth (LB*) or in LB* supplemented with one of the non-metabolizable analogues 2-deoxy-d-glucose (2DG), methyl α-d-mannopyranoside (αMM), or methyl α-d-glucopyranoside (αMG). Biofilm growth was inhibited by mannose analogue 2DG even at very low concentration in unbuffered medium, and the maximal inhibition was enhanced in the presence of either 100 mM KPO4 or 100 mM MOPS, pH 7.5; in buffered medium, concentrations of 0.02 % (1.2 mM) or more inhibited growth nearly completely. In contrast, mannose analogue αMM, which should not be able to enter the cells but has been reported to inhibit biofilm growth by binding to FimH, did not exhibit strong inhibition even at concentrations up to 1.8 % (108 mM). The glucose analogue αMG inhibited biofilm growth, but much less strongly than did 2DG. None of the analogues inhibited planktonic growth or caused a change in pH of the unbuffered medium. Similar inhibitory effects of the analogues were observed in minimal medium. The effects were not strain-specific, as 2DG and αMG also inhibited the weak biofilm growth of E. coli K12.}, } @article {pmid27045190, year = {2016}, author = {Corvec, S and Aubin, GG and Bayston, R and Ashraf, W}, title = {Which is the best treatment for prosthetic joint infections due to Propionibacterium acnes: need for further biofilm in vitro and experimental foreign-body in vivo studies?.}, journal = {Acta orthopaedica}, volume = {87}, number = {3}, pages = {318-319}, pmid = {27045190}, issn = {1745-3682}, mesh = {Anti-Bacterial Agents ; *Biofilms ; Gram-Positive Bacterial Infections/microbiology ; *Propionibacterium acnes ; Prostheses and Implants ; }, } @article {pmid27044552, year = {2016}, author = {Stiefel, P and Mauerhofer, S and Schneider, J and Maniura-Weber, K and Rosenberg, U and Ren, Q}, title = {Enzymes Enhance Biofilm Removal Efficiency of Cleaners.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {6}, pages = {3647-3652}, pmid = {27044552}, issn = {1098-6596}, mesh = {Biofilms/*drug effects/growth & development ; Colony Count, Microbial ; Cross Infection/prevention & control ; Deoxyribonucleases/chemistry/*pharmacology ; Detergents/chemistry/pharmacology ; Disinfectants/chemistry/*pharmacology ; Disinfection ; Endoscopes/microbiology ; Equipment Contamination ; Humans ; Lipase/chemistry/*pharmacology ; Peptide Hydrolases/chemistry/*pharmacology ; Polysaccharides/chemistry/pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {Efficient removal of biofilms from medical devices is a big challenge in health care to avoid hospital-acquired infections, especially from delicate devices like flexible endoscopes, which cannot be reprocessed using harsh chemicals or high temperatures. Therefore, milder solutions such as enzymatic cleaners have to be used, which need to be carefully developed to ensure efficacious performance. In vitro biofilm in a 96-well-plate system was used to select and optimize the formulation of novel enzymatic cleaners. Removal of the biofilm was quantified by crystal violet staining, while the disinfecting properties were evaluated by a BacTiter-Glo assay. The biofilm removal efficacy of the selected cleaner was further tested by using European standard (EN) for endoscope cleaning EN ISO 15883, and removal of artificial blood soil was investigated by treating TOSI (Test Object Surgical Instrument) cleaning indicators. Using the process described here, a novel enzymatic endoscope cleaner was developed, which removed 95% of Staphylococcus aureus and 90% of Pseudomonas aeruginosa biofilms in the 96-well plate system. With a >99% reduction of CFU and a >90% reduction of extracellular polymeric substances, this cleaner enabled subsequent complete disinfection and fulfilled acceptance criteria of EN ISO 15883. Furthermore, it efficiently removed blood soil and significantly outperformed comparable commercial products. The cleaning performance was stable even after storage of the cleaner for 6 months. It was demonstrated that incorporation of appropriate enzymes into the cleaner enhanced performance significantly.}, } @article {pmid27043385, year = {2016}, author = {Kim, NH and Rhee, MS}, title = {Synergistic bactericidal action of phytic acid and sodium chloride against Escherichia coli O157:H7 cells protected by a biofilm.}, journal = {International journal of food microbiology}, volume = {227}, number = {}, pages = {17-21}, doi = {10.1016/j.ijfoodmicro.2016.03.026}, pmid = {27043385}, issn = {1879-3460}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Colony Count, Microbial ; Escherichia coli O157/*drug effects ; Food Handling ; *Food Microbiology ; Phytic Acid/*pharmacology ; Sodium Chloride/*pharmacology ; Stainless Steel/pharmacology ; }, abstract = {The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22°C for 6days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (p<0.05); thus M9 medium was selected for further experiments. The anti-biofilm effect of PA was significantly increased by addition of NaCl (2-4%) (p<0.05); indeed, the combination of 0.4% PA plus 3-4% NaCl completely inactivated E. coli O157:H7 biofilms without recovery (a>6.5logCFU/cm(2) reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7logCFU/cm(2) reduction; NaCl, <0.5logCFU/cm(2) reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2-4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments.}, } @article {pmid27042294, year = {2016}, author = {Tajbakhsh, E and Ahmadi, P and Abedpour-Dehkordi, E and Arbab-Soleimani, N and Khamesipour, F}, title = {Biofilm formation, antimicrobial susceptibility, serogroups and virulence genes of uropathogenic E. coli isolated from clinical samples in Iran.}, journal = {Antimicrobial resistance and infection control}, volume = {5}, number = {}, pages = {11}, pmid = {27042294}, issn = {2047-2994}, abstract = {BACKGROUND: Uropathogenic Escherichia coli O- Serogroups with their virulence factors are the most prevalent causes of UTIs. The present research performed to track common uropathogenic E.coli serogroups, antibiotic resistance pattern of strains and prevalence of virulence genes in isolations having the ability to constitute biofilm.

METHODS: In this research 130 E.coli isolation from patients having UTI symptoms were collected and antimicrobial resistance pattern was performed by Kirby-Bauer method. Polymerase chain reaction was done using primer pairs to identify common serogroups of uropathogenic E.coli and studying virulence genes in isolations creating biofilm.

RESULTS: Among 130 E.coli isolates, 80 (61.53 %) were able to make biofilm that 15 isolates (18.75 %) indicated strong reaction, 20 (25 %) of medium and 45 (56.25 %) of weak biofilm reaction. Among isolations creating biofilm, the highest resistance reported to Ampicillin (87.5 %) and the lowest to Nitrofurantoin (3.75 %). The frequency of fimH, pap, sfa and afa genes in isolations having the ability to create strong biofilm reported 93.33 %, 86.66 %, 86.66 % and 66.66 %, respectively.

CONCLUSIONS: The findings indicated the importance of virulence genes in serogroups producing uropathogenic E.coli biofilm. It is recommended that strains producing biofilm before antibiotic use should be studied.}, } @article {pmid27038917, year = {2016}, author = {Nguyen, V and Karunakaran, E and Collins, G and Biggs, CA}, title = {Physicochemical analysis of initial adhesion and biofilm formation of Methanosarcina barkeri on polymer support material.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {143}, number = {}, pages = {518-525}, doi = {10.1016/j.colsurfb.2016.03.042}, pmid = {27038917}, issn = {1873-4367}, mesh = {Anaerobiosis/physiology ; Bacterial Adhesion/*drug effects ; Biodegradation, Environmental ; Biofilms/*drug effects/growth & development ; Bioreactors ; Methanosarcina barkeri/*drug effects/growth & development ; Polypropylenes/chemistry/*pharmacology ; Polytetrafluoroethylene/chemistry/*pharmacology ; Polyvinyl Chloride/chemistry/*pharmacology ; Sewage/microbiology ; Surface Properties ; }, abstract = {The retention of selective biofilms of Methanosarcina species within anaerobic digesters could reduce start-up times and enhance the efficiency of the process in treating high-strength domestic sewage. The objective of the study was to examine the effect of the surface characteristics of six common polymer support materials on the initial adhesion of the model methanogen, Methanosarcina barkeri, and to assess the potential of these support materials as selective biofilm carriers. Results from both the initial adhesion tests and extended DLVO (xDLVO) model correlated with each other, with PVC (12% surface coverage/mm(2)), PTFE (6% surface coverage/mm(2)), and PP (6% surface coverage/mm(2)), shown to be the better performing support materials for initial adhesion, as well as subsequent biofilm formation by M. barkeri after 72h. Experimental results of these three support materials showed that the type of material strongly influenced the extent of adhesion from M. barkeri (p<0.0001), and the xDLVO model was able to explain the results in these environmental conditions. Therefore, DLVO physicochemical forces were found to be influential on the initial adhesion of M. barkeri. Scanning electron microscopy suggested that production of extracellular polymeric substances (EPS) from M. barkeri could facilitate further biofilm development. This study highlights the potential of using the xDLVO model to rapidly identify suitable materials for the selective adhesion of M. barkeri, which could be beneficial in both the start-up and long-term phases of anaerobic digestion.}, } @article {pmid27038266, year = {2016}, author = {Tang, B and Yu, C and Bin, L and Zhao, Y and Feng, X and Huang, S and Fu, F and Ding, J and Chen, C and Li, P and Chen, Q}, title = {Essential factors of an integrated moving bed biofilm reactor-membrane bioreactor: Adhesion characteristics and microbial community of the biofilm.}, journal = {Bioresource technology}, volume = {211}, number = {}, pages = {574-583}, doi = {10.1016/j.biortech.2016.03.136}, pmid = {27038266}, issn = {1873-2976}, mesh = {Biofilms/growth & development ; Bioreactors/*microbiology ; Equipment Design ; *Membranes, Artificial ; *Microbial Consortia ; }, abstract = {This work aims at revealing the adhesion characteristics and microbial community of the biofilm in an integrated moving bed biofilm reactor-membrane bioreactor, and further evaluating their variations over time. With multiple methods, the adhesion characteristics and microbial community of the biofilm on the carriers were comprehensively illuminated, which showed their dynamic variation along with the operational time. Results indicated that: (1) the roughness of biofilm on the carriers increased very quickly to a maximum value at the start-up stage, then, decreased to become a flat curve, which indicated a layer of smooth biofilm formed on the surface; (2) the tightly-bound protein and polysaccharide was the most important factor influencing the stability of biofilm; (3) the development of biofilm could be divided into three stages, and Gammaproteobacteria were the most dominant microbial species in class level at the last stage, which occupied the largest ratio (51.48%) among all microbes.}, } @article {pmid27038261, year = {2016}, author = {Iman Shayan, S and Agblevor, FA and Bertin, L and Sims, RC}, title = {Hydraulic retention time effects on wastewater nutrient removal and bioproduct production via rotating algal biofilm reactor.}, journal = {Bioresource technology}, volume = {211}, number = {}, pages = {527-533}, doi = {10.1016/j.biortech.2016.03.104}, pmid = {27038261}, issn = {1873-2976}, mesh = {Biofilms ; Bioreactors ; Lipid Metabolism ; Microalgae/growth & development/*metabolism ; Nitrogen/metabolism ; Phosphorus/metabolism ; Starch/metabolism ; Time Factors ; Waste Management/*methods ; Wastewater/*chemistry ; }, abstract = {Rotating algal biofilm reactor (RABR) technology was successfully employed in an effective strategy to couple the removal of wastewater nutrients with accumulation of valuable bioproducts by grown algae. A secondary stage municipal wastewater was fed to the developed system and the effects of the hydraulic retention time (HRT) parameter on both nutrient removal and bioproduct production were evaluated under fed-batch operation mode. Two sets of bench scale RABRs were designed and operated with HRTs of 2 and 6days in order to provide competitive environment for algal growth. The HRT significantly affected nitrogen and phosphorus uptakes along with lipid and starch accumulations by microalgae in harvested biofilms. Domination of nitrogen removal in 2-day HRT with higher lipid accumulation (20% on dried weight basis) and phosphorus removal in 6-day HRT with higher starch production (27% on dried weight basis) was observed by comparing the performances of the RABRs in duplicate runs.}, } @article {pmid27037969, year = {2016}, author = {Revetta, RP and Gomez-Alvarez, V and Gerke, TL and Santo Domingo, JW and Ashbolt, NJ}, title = {Changes in bacterial composition of biofilm in a metropolitan drinking water distribution system.}, journal = {Journal of applied microbiology}, volume = {121}, number = {1}, pages = {294-305}, doi = {10.1111/jam.13150}, pmid = {27037969}, issn = {1365-2672}, mesh = {Bacteria/classification/genetics/*isolation & purification ; *Biodiversity ; *Biofilms ; Chlorine/analysis ; Drinking Water/analysis/*microbiology ; Groundwater/analysis/microbiology ; Water Purification ; Water Quality ; Water Supply/standards ; }, abstract = {AIMS: This study examined the development of bacterial biofilms within a metropolitan distribution system. The distribution system is fed with different source water (i.e. groundwater, GW and surface water, SW) and undergoes different treatment processes in separate facilities.

METHODS AND RESULTS: The biofilm community was characterized using 16S rRNA gene clone libraries and functional potential analysis, generated from total DNA extracted from coupons in biofilm annular reactors fed with onsite drinking water for up to 18 months. Differences in the bacterial community structure were observed between GW and SW. Representatives that explained the dissimilarity were associated with the classes Betaproteobacteria, Alphaproteobacteria, Actinobacteria, Gammaproteobacteria and Firmicutes. After 9 months the biofilm bacterial community from both GW and SW were dominated by Mycobacterium species. The distribution of the dominant operational taxonomic unit (OTU) (Mycobacterium) positively correlated with the drinking water distribution system (DWDS) temperature.

CONCLUSIONS: In this study, the biofilm community structure observed between GW and SW were dissimilar, while communities from different locations receiving SW did not show significant differences. The results suggest that source water and/or the water quality shaped by their respective treatment processes may play an important role in shaping the bacterial communities in the distribution system. In addition, several bacterial groups were present in all samples, suggesting that they are an integral part of the core microbiota of this DWDS.

These results provide an ecological insight into biofilm bacterial structure in chlorine-treated drinking water influenced by different water sources and their respective treatment processes.}, } @article {pmid27036412, year = {2016}, author = {Jørgensen, NP and Skovdal, SM and Meyer, RL and Dagnæs-Hansen, F and Fuursted, K and Petersen, E}, title = {Rifampicin-containing combinations are superior to combinations of vancomycin, linezolid and daptomycin against Staphylococcus aureus biofilm infection in vivo and in vitro.}, journal = {Pathogens and disease}, volume = {74}, number = {4}, pages = {ftw019}, doi = {10.1093/femspd/ftw019}, pmid = {27036412}, issn = {2049-632X}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/pharmacology ; Biofilms/*drug effects/growth & development ; Daptomycin/administration & dosage/*pharmacology ; Disease Models, Animal ; Drug Resistance, Bacterial ; Drug Synergism ; Drug Therapy, Combination ; Female ; Linezolid/administration & dosage/*pharmacology ; Mice ; Microbial Sensitivity Tests ; Osteomyelitis/drug therapy/microbiology ; Prostheses and Implants/microbiology ; Rifampin/administration & dosage/*pharmacology ; Staphylococcal Infections/drug therapy/*microbiology ; Staphylococcus aureus/*drug effects/*physiology ; Treatment Outcome ; Vancomycin/administration & dosage/*pharmacology ; }, abstract = {Susceptibility to antibiotics is dramatically reduced when bacteria form biofilms. In clinical settings this has a profound impact on treatment of implant-associated infections, as these are characterized by biofilm formation. Current routine susceptibility testing of microorganisms from infected implants does not reflect the actual susceptibility, and the optimal antibiotic strategy for treating implant-associated infections is not established. In this study of biofilm formation in implant-associated osteomyelitis, we compared thein vitroandin vivoefficacy of selected antibiotics alone and in combination againstStaphylococcus aureus.We tested vancomycin, linezolid, daptomycin and tigecycline alone and in combination with rifampicin, vancomycin, linezolid and daptomycin againstS. aureusIn vitro, biofilm formation dramatically reduced susceptibility by a factor of 500-2000.In vivo, antibiotic combinations were tested in a murine model of implant-associated osteomyelitis. Mice were infected by inserting implants colonized withS. aureustrough their tibia. After 11 days, the animals were divided into different groups (five animals/group) and given 14 days of antibiotic therapy. All antibiotics resulted in a reduced bacterial load in the infected bone surrounding the implant. Overall, the most effective antibiotic combinations contained rifampicin. Combinations containing two non-rifampicin antibiotics were not more active than single drugs.}, } @article {pmid27032997, year = {2016}, author = {Manti, A and Ciandrini, E and Campana, R and Dominici, S and Ciacci, C and Federici, S and Sisti, D and Rocchi, MB and Papa, S and Baffone, W}, title = {A dual-species microbial model for studying the dynamics between oral streptococci and periodontal pathogens during biofilm development on titanium surfaces by flow cytometry.}, journal = {Research in microbiology}, volume = {167}, number = {5}, pages = {393-402}, doi = {10.1016/j.resmic.2016.03.004}, pmid = {27032997}, issn = {1769-7123}, mesh = {Biofilms/*growth & development ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Fusobacterium nucleatum/growth & development/*physiology ; Gentian Violet/analysis ; *Microbial Interactions ; Mouth/*microbiology ; Porphyromonas gingivalis/growth & development/*physiology ; Staining and Labeling ; Streptococcus/growth & development/*physiology ; *Titanium ; }, abstract = {The association of the pioneer organisms Streptococcus mutans ATCC 25175 or Streptococcus oralis ATCC 9811 with secondary colonizers Fusobacterium nucleatum ATCC 25586 or Porphyromonas gingivalis ATCC 33277 during biofilm development on titanium surfaces was evaluated by flow cytometry (FCM) using specific polyclonal antibodies. ELISA and FCM were employed, revealing high antibody sensitivity and specificity. Biofilm formation of four dual-species combinations was analyzed by crystal violet staining, while the association between streptococci and periodontal pathogens was assessed using FCM. Dual-species association between S. oralis and P. gingivalis or F. nucleatum showed a proportional decrease in S. oralis during biofilm development, with a concomitant increase in P. gingivalis or F. nucleatum. This trend was not observed in either of the dual-species associations of S. mutans with the periodontal pathogens. Our dual-species microbial model, which employed FCM, proved to be useful in the study of partnerships between bacteria in oral associations, showing that the presence of primary colonizers is required for the establishment of secondary colonizers in biofilms. The proposed experimental approach is technically simple to prepare and analyze, and also proved to be reproducible; hence, it is well-suited for investigating the development and dynamics of oral communities.}, } @article {pmid27032634, year = {2017}, author = {Cabrera-Orozco, A and Galíndez-Nájera, SP and Ruiz-Ordaz, N and Galíndez-Mayer, J and Martínez-Jerónimo, F}, title = {Erratum to: Biodegradation of a commercial mixture of the herbicides atrazine and S-metolachlor in a multi-channel packed biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {33}, pages = {25666}, doi = {10.1007/s11356-016-6496-5}, pmid = {27032634}, issn = {1614-7499}, } @article {pmid27032404, year = {2016}, author = {Peng, YL and Meng, QL and Qiao, J and Xie, K and Chen, C and Liu, TL and Hu, ZX and Ma, Y and Cai, XP and Chen, CF}, title = {The Regulatory Roles of ncRNA Rli60 in Adaptability of Listeria monocytogenes to Environmental Stress and Biofilm Formation.}, journal = {Current microbiology}, volume = {73}, number = {1}, pages = {77-83}, pmid = {27032404}, issn = {1432-0991}, mesh = {Adaptation, Physiological ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; *Gene Expression Regulation, Bacterial ; Humans ; Listeria monocytogenes/genetics/*physiology ; RNA, Bacterial/genetics/*metabolism ; RNA, Long Noncoding/genetics/*metabolism ; Stress, Physiological ; }, abstract = {Listeria monocytogenes is a facultative anaerobic Gram-positive bacterium. It is well adapted to external environments and able to infect both humans and animals. To understand the impacts of ncRNA Rli60 on the adaptability of L. monocytogenes to environmental stresses and biofilm formation, a rli60 deletion strain of L. monocytogenes (LM-Δrli60) was constructed using splicing by overlap extension PCR (SOE-PCR) and homologous recombination and then compared it with wild-type strain L. monocytogenes EGD-e in the aspects of adaptability to environmental stresses by measuring their growth under stresses of different temperatures, and acidic, alkaline, hypertonic and alcoholic conditions, and capability of biofilm formation by using crystal violet staining, as well as the transcriptional levels of genes (gltB and gltC) related to the biofilm formation by real-time quantitative PCR (qRT-PCR). The results showed that (1) the growth of LM-Δrli60 strain was significantly slower under environmental stresses of low temperature (30 °C), high temperature (42 °C), as well as alkaline and alcoholic conditions, (2) the amount of biofilm formed by LM-Δrli60 was attenuated, and (3) the transcriptional levels of gltB and gltC genes at 24 h and 48 h in LM-Δrli60 revealed a significant reduction. Overall, the results confirmed that ncRNA Rli60 plays important roles in regulating the adaptability of L. monocytogenes to environmental stresses and biofilm formation possibly through impacting the expression of gltB and gltC genes.}, } @article {pmid27032256, year = {2015}, author = {Ippolitov, EV and Didenko, LV and Tzarev, VN}, title = {[THE CHARACTERISTICS OF MORPHOLOGY OF BIOFILM OF PERIODONTIUM UNDER INFLAMMATORY DISEASES OF GUMS (CHRONIC CATARRHAL GINGIVITIS, CHRONIC PERIODONTITIS, CANDIDA-ASSOCIATED PERIODONTITIS) ACCORDING RESULTS OF ELECTRONIC MICROSCOPY].}, journal = {Klinicheskaia laboratornaia diagnostika}, volume = {60}, number = {12}, pages = {59-64}, pmid = {27032256}, issn = {0869-2084}, mesh = {Adolescent ; Adult ; Aggregatibacter actinomycetemcomitans/genetics/isolation & purification/*ultrastructure ; Biofilms/classification/*growth & development ; Candida albicans/genetics/isolation & purification/*ultrastructure ; Case-Control Studies ; Chronic Disease ; Diagnosis, Differential ; Female ; Gingiva/microbiology/ultrastructure ; Gingivitis/*diagnosis/microbiology/pathology ; Humans ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; Periodontitis/*diagnosis/microbiology/pathology ; Polymerase Chain Reaction ; Porphyromonas gingivalis/genetics/isolation & purification/*ultrastructure ; Prevotella intermedia/genetics/isolation & purification/*ultrastructure ; Reagent Kits, Diagnostic ; Severity of Illness Index ; }, abstract = {The study was carried out to analyze morphology of biofilm of periodontium and to develop electronic microscopic criteria of differentiated diagnostic of inflammatory diseases of gums. The scanning electronic microscopy was applied to analyze samples of bioflm of periodont from 70 patients. Including ten patients with every nosologic form of groups with chronic catarrhal periodontitis. of light, mean and severe degree, chronic catarrhal gingivitis, Candida-associated paroperiodontitis and 20 healthy persons with intact periodontium. The analysis was implemented using dual-beam scanning electronic microscope Quanta 200 3D (FEI company, USA) and walk-through electronic micJEM 100B (JEOL, Japan). To detect marker DNA of periodont pathogenic bacteria in analyzed samples the kit of reagentsfor polymerase chain reaction "MultiDent-5" ("GenLab", Russia). The scanning electronic microscopy in combination with transmission electronic microscopy and polymerase chain reaction permits analyzing structure, composition and degree of development of biofilm of periodontium and to apply differentiated diagnostic of different nosologic forms of inflammatory diseases of periodontium, including light form of chronic periodontitis and gingivitis. The electronic microscopical indications of diseases ofperiodontium of inflammatory character are established: catarrhal gingivitis, (coccal morphological alternate), chronic periodontitis (bacillary morphological alternate), Candida-associated periodontitis (Candida morphological alternate of biofilm ofperiodontium).}, } @article {pmid27031799, year = {2016}, author = {Mallevre, F and Fernandes, TF and Aspray, TJ}, title = {Pseudomonas putida biofilm dynamics following a single pulse of silver nanoparticles.}, journal = {Chemosphere}, volume = {153}, number = {}, pages = {356-364}, doi = {10.1016/j.chemosphere.2016.03.060}, pmid = {27031799}, issn = {1879-1298}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; *Metal Nanoparticles ; Pseudomonas putida/*drug effects/*physiology ; Silver/*pharmacology ; }, abstract = {Pseudomonas putida mono-species biofilms were exposed to silver nanoparticles (Ag NPs) in artificial wastewater (AW) under hydrodynamic conditions. Specifically, 48 h old biofilms received a single pulse of Ag NPs at 0, 0.01, 0.1, 1, 10 and 100 mg L(-1) for 24 h in confocal laser scanning microscopy (CLSM) compatible flow-cells. The biofilm dynamics (in terms of morphology, viability and activity) were characterised at 48, 72 and 96 h. Consistent patterns were found across flow-cells and experiments at 48 h. Dose dependent impacts of NPs were then shown at 72 h on biofilm morphology (e.g. biomass, surface area and roughness) from 0.01 mg L(-1). The microbial viability was not altered below 10 mg L(-1) Ag NPs. The activity (based on the d-glucose utilisation) was impacted by concentrations of Ag NPs equal and superior to 10 mg L(-1). Partial recovery of morphology, viability and activity were finally observed at 96 h. Comparatively, exposure to Ag salt resulted in ca. one order of magnitude higher toxicity when compared to Ag NPs. Consequently, the use of a continuous culture system and incorporation of a recovery stage extends the value of biofilm assays beyond the standard acute toxicity assessment.}, } @article {pmid27031025, year = {2016}, author = {Strus, M and Mikołajczyk, D and Machul, A and Heczko, PB and Chronowska, A and Stochel, G and Gallienne, E and Nicolas, C and Martin, OR and Kyzioł, A}, title = {Effects of the Selected Iminosugar Derivatives on Pseudomonas aeruginosa Biofilm Formation.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {22}, number = {8}, pages = {638-645}, doi = {10.1089/mdr.2015.0231}, pmid = {27031025}, issn = {1931-8448}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Caco-2 Cells ; Cell Survival/drug effects ; Colony Count, Microbial ; Humans ; Imino Sugars/chemistry/*pharmacology ; Microbial Viability/drug effects ; Polysaccharides, Bacterial/*antagonists & inhibitors/biosynthesis ; Pseudomonas aeruginosa/*drug effects/growth & development/metabolism ; Species Specificity ; Structure-Activity Relationship ; }, abstract = {A lack of an effective way to eliminate pathogenic bacteria hidden in the biofilm is a major problem in the treatment of chronic bacterial infections. Iminosugar derivatives are potential candidates for inhibitors of enzymes taking part in the biosynthesis of exopolysaccharides, which are forming bacterial biofilm. Investigated iminosugars were studied either at an early stage of biofilm formation or later on when the mature biofilm of Pseudomonas aeruginosa was already formed. A series of diverse iminosugar structures significantly inhibited biofilm formation, whereas they showed no influence on already formed biofilm. This indicates a possible mechanism of their action based on inhibition of exopolysaccharide backbone synthesis in the early stages of biofilm formation. Moreover, iminosugar derivatives did not show significant effect on the viable bacterial numbers in both early and mature biofilm forms. Importantly, they were not cytotoxic against human Caco-2 cells in vitro, which may be to their advantage in case of their medical application in preventing P. aeruginosa biofilm formation.}, } @article {pmid27030953, year = {2016}, author = {Hu, H and He, J and Liu, J and Yu, H and Zhang, J}, title = {Biofilm activity and sludge characteristics affected by exogenous N-acyl homoserine lactones in biofilm reactors.}, journal = {Bioresource technology}, volume = {211}, number = {}, pages = {339-347}, doi = {10.1016/j.biortech.2016.03.068}, pmid = {27030953}, issn = {1873-2976}, mesh = {Acyl-Butyrolactones/*pharmacology ; Bacteria ; Biofilms/*drug effects/growth & development ; Bioreactors ; Chromatography, High Pressure Liquid ; Nitrification ; Nitrogen/*metabolism ; Quorum Sensing ; Sewage/chemistry/*microbiology ; Tandem Mass Spectrometry ; Waste Management/methods ; }, abstract = {This study verified the effect of N-acyl homoserine lactone (AHL) concentrations on mature biofilm systems. Three concentrations of an AHL mixture were used in the batch test. Introducing of 5nM AHLs significantly increased biofilm activity and increased sludge characteristics, which resulted in better pollutant removal performance, whereas exogenous 50nM and 500nM AHLs limited pollutant removal, especially COD and nitrogen removal. To further identify how exogenous signal molecular affects biofilm system nitrogen removal, analyzing of nitrifying bacteria through real-time polymerase chain reaction (RT-PCR) revealed that these additional signal molecules affect nitrifying to total bacteria ratio. In addition, the running state of the system was stable during 15days of operation without an AHL dose, which suggests that the changes in the system due to AHL are irreversible.}, } @article {pmid27030404, year = {2016}, author = {Haque, F and Alfatah, M and Ganesan, K and Bhattacharyya, MS}, title = {Inhibitory Effect of Sophorolipid on Candida albicans Biofilm Formation and Hyphal Growth.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {23575}, pmid = {27030404}, issn = {2045-2322}, mesh = {Amphotericin B/pharmacology ; Antifungal Agents/isolation & purification/*pharmacology ; Aspartic Acid Endopeptidases/antagonists & inhibitors/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/genetics/growth & development/ultrastructure ; Drug Combinations ; Drug Synergism ; Fluconazole/pharmacology ; Fungal Proteins/antagonists & inhibitors/genetics/metabolism ; Gene Expression Regulation, Fungal/drug effects ; Glycolipids/isolation & purification/*pharmacology ; Hyphae/*drug effects/genetics/growth & development/ultrastructure ; Membrane Glycoproteins/antagonists & inhibitors/genetics/metabolism ; Microbial Sensitivity Tests ; Microbial Viability ; Saccharomycetales/chemistry ; Surface-Active Agents/isolation & purification/*pharmacology ; }, abstract = {Candida albicans causes superficial and life-threatening systemic infections. These are difficult to treat often due to drug resistance, particularly because C. albicans biofilms are inherently resistant to most antifungals. Sophorolipid (SL), a glycolipid biosurfactant, has been shown to have antimicrobial and anticancer properties. In this study, we investigated the effect of SL on C. albicans biofilm formation and preformed biofilms. SL was found to inhibit C. albicans biofilm formation as well as reduce the viability of preformed biofilms. Moreover, SL, when used along with amphotericin B (AmB) or fluconazole (FLZ), was found to act synergistically against biofilm formation and preformed biofilms. Effect of SL on C. albicans biofilm formation was further visualized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), which revealed absence of hyphae, typical biofilm architecture and alteration in the morphology of biofilm cells. We also found that SL downregulates the expression of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4, which possibly explains the inhibitory effect of SL on hyphae and biofilm formation.}, } @article {pmid27028292, year = {2016}, author = {Ahire, JJ and Hattingh, M and Neveling, DP and Dicks, LM}, title = {Copper-Containing Anti-Biofilm Nanofiber Scaffolds as a Wound Dressing Material.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0152755}, pmid = {27028292}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/*chemistry ; *Bandages ; Biofilms/*growth & development ; Copper/*chemistry ; Nanofibers/*chemistry ; Pseudomonas aeruginosa/*physiology ; Staphylococcus aureus/*physiology ; Surface Properties ; }, abstract = {Copper particles were incorporated into nanofibers during the electrospinning of poly-D,L-lactide (PDLLA) and poly(ethylene oxide) (PEO). The ability of the nanofibers to prevent Pseudomonas aeruginosa PA01 and Staphylococcus aureus (strain Xen 30) to form biofilms was tested. Nanofibers containing copper particles (Cu-F) were thinner (326 ± 149 nm in diameter), compared to nanofibers without copper (CF; 445 ± 93 nm in diameter). The crystalline structure of the copper particles in Cu-F was confirmed by X-ray diffraction (XRD). Copper crystals were encapsulated, but also attached to the surface of Cu-F, as shown scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM), respectively. The copper particles had no effect on the thermal degradation and thermal behaviour of Cu-F, as shown by thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). After 48 h in the presence of Cu-F, biofilm formation by P. aeruginosa PA01 and S. aureus Xen 30 was reduced by 41% and 50%, respectively. Reduction in biofilm formation was ascribed to copper released from the nanofibers. Copper-containing nanofibers may be incorporated into wound dressings.}, } @article {pmid27025850, year = {2016}, author = {Audoly, G and Fenollar, F and Lagier, JC and Lepidi, H and Raoult, D}, title = {Deglycosylation of Tropheryma whipplei biofilm and discrepancies between diagnostic results during Whipple's disease progression.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {23883}, pmid = {27025850}, issn = {2045-2322}, mesh = {Anti-Bacterial Agents/pharmacology/therapeutic use ; Bacteriolysis ; *Biofilms ; Biopsy ; Disease Progression ; Duodenum/microbiology/pathology ; Glycoside Hydrolases/chemistry/pharmacology ; Glycosylation ; Humans ; Intestinal Mucosa/microbiology/pathology ; Lymph Nodes/microbiology/pathology ; Microscopy, Confocal ; Tropheryma/*physiology ; Whipple Disease/*diagnosis/drug therapy/microbiology ; }, abstract = {Whipple's disease is a systemic infectious disease associated with the bacterium Tropheryma whipplei. Numerous reports have presented puzzling discrepancies between diagnosis methods. We addressed this confusion using fluorescent in situ hybridization and immunofluorescence assays to evaluate 34 duodenal biopsies and 1 lymph node biopsy from Whipple's patients. We showed the presence of bacteria in both CK20(+) epithelial cells and CD68(+) macrophages. Bacteria are found embedded in a biofilm hindering the detection of T. whipplei. Only after treatment of biopsies by glycosidases, co-localization of T. whipplei RNA/DNA with bacterial proteins was restored. Moreover, using 13 bronchoalveolar lavages and 7 duodenal biopsies, we found that hydrolysis of the biofilm weakened the bacteria, facilitated bacterial DNA extraction and improved the sensitivity of qPCR detection by up to 1000x opening new perspectives for diagnostic and scientific approaches.}, } @article {pmid27025518, year = {2016}, author = {Abraham, WR}, title = {Going beyond the Control of Quorum-Sensing to Combat Biofilm Infections.}, journal = {Antibiotics (Basel, Switzerland)}, volume = {5}, number = {1}, pages = {}, pmid = {27025518}, issn = {2079-6382}, abstract = {Most bacteria attach to surfaces where they form a biofilm, cells embedded in a complex matrix of polymers. Cells in biofilms are much better protected against noxious agents than free-living cells. As a consequence it is very difficult to control pathogens with antibiotics in biofilm infections and novel targets are urgently needed. One approach aims at the communication between cells to form and to maintain a biofilm, a process called quorum-sensing. Water soluble small-sized molecules mediate this process and a number of antagonists of these compounds have been found. In this review natural compounds and synthetic drugs which do not interfere with the classical quorum-sensing compounds are discussed. For some of these compounds the targets are still not known, but others interfere with the formation of exopolysaccharides, virulence factors, or cell wall synthesis or they start an internal program of biofilm dispersal. Some of their targets are more conserved among pathogens than the receptors for quorum sensing autoinducers mediating quorum-sensing, enabling a broader application of the drug. The broad spectrum of mechanisms, the diversity of bioactive compounds, their activity against several targets, and the conservation of some targets among bacterial pathogens are promising aspects for several clinical applications of this type of biofilm-controlling compound in the future.}, } @article {pmid27023382, year = {2016}, author = {Zheng, B and Zhang, L and Guo, J and Zhang, S and Yang, A and Peng, Y}, title = {Suspended sludge and biofilm shaped different anammox communities in two pilot-scale one-stage anammox reactors.}, journal = {Bioresource technology}, volume = {211}, number = {}, pages = {273-279}, doi = {10.1016/j.biortech.2016.03.049}, pmid = {27023382}, issn = {1873-2976}, mesh = {Ammonium Compounds/*metabolism ; Anaerobiosis ; *Bacteria/chemistry/metabolism ; *Biofilms ; Bioreactors/*microbiology ; Oxidation-Reduction ; Pilot Projects ; Sewage/*microbiology ; }, abstract = {The abundance and diversity of anammox bacteria was investigated in two pilot-scale integrated fixed-film activated sludge (IFAS) reactors treating high ammonium wastewater. Reactor A was inoculated with nitrifying sludge, while Reactor B was inoculated with suspended anammox sludge with the dominant anammox bacteria of Candidatus 'Kuenenia'. After 180days' operation, the predominate anammox bacteria was Candidatus 'Brocadia' (65%) in the biofilm, while Candidatus 'Kuenenia' (86%) outcompeted with other anammox bacteria in suspended sludge in Reactor A. Candidatus 'Kuenenia' were dominated in suspended sludge through the entire experiment in Reactor B. In contrast, the predominated species shifted from Candidatus 'Kuenenia' (89%) into Candidatus 'Brocadia' (66%) in the biofilm of Reactor B. This study indicated that Candidatus 'Brocadia' preferred to grow in the biofilm, while Candidatus 'Kuenenia' would dominant over other anammox bacteria in the suspended sludge. Further studies are required to identify the internal factors affecting the distribution of anammox bacteria.}, } @article {pmid27023165, year = {2016}, author = {Wang, J and Stanford, K and McAllister, TA and Johnson, RP and Chen, J and Hou, H and Zhang, G and Niu, YD}, title = {Biofilm Formation, Virulence Gene Profiles, and Antimicrobial Resistance of Nine Serogroups of Non-O157 Shiga Toxin-Producing Escherichia coli.}, journal = {Foodborne pathogens and disease}, volume = {13}, number = {6}, pages = {316-324}, doi = {10.1089/fpd.2015.2099}, pmid = {27023165}, issn = {1556-7125}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; *Biofilms/growth & development ; Canada ; Cattle ; Drug Resistance, Bacterial ; Food Microbiology ; Humans ; Phenotype ; Serogroup ; Sheep ; Shiga-Toxigenic Escherichia coli/classification/drug effects/genetics/*physiology ; Virulence Factors/genetics ; }, abstract = {The objectives of this study were to characterize the phenotype and genotype of 36 non-O157 Shiga toxin-producing Escherichia coli (STEC) strains isolated from humans, ovines, or bovines, including the top 6 (O26, O45, O103, O111, O121, and O145) and three other serogroups implicated in serious illness (O91, O113, and O128). Biofilms were formed by all strains with intermediate to strong biofilm producers (n = 24) more common at 22°C than at 37°C (p < 0.001) and 48 and 72 h (p < 0.001) than 24 h of incubation time. Biofilm-forming potential differed by serogroup and origin with O113 and human strains exhibiting the highest potential (p < 0.001). Biofilm-associated genes, csgA/csgD/crl/fimH (100%), flu (94%), rpoS (92%), ehaA(α) (89%), and cah (72%), were most prevalent, while mlrA (22%) and ehaA(β) (14%) were least prevalent, although there was no clear compliment of genes associated with strains exhibiting the greatest biofilm-forming capacity. Among 12 virulence genes screened, iha and ehxA were present in 92% of the strains. The occurrence of stx1 in the top 6 serogroups (8/12, 67%) did not differ (p = 0.8) from other serogroups (17/24, 71%), but stx2 was less likely (confidence interval [CI] = 0.14-1.12; p = 0.04) to be in the former (9/24, 38%) than the latter (9/12, 75%). Excluding serogroups, O91 and O121, at least one strain per serogroup was resistant to between three and six antimicrobials. Streptomycin (31%), sulfisoxazole (31%), and tetracycline (25%) resistance was most common and was 35-50% less likely (p < 0.05) in human than animal strains. All non-O157 STEC strains were able to form biofilms on an abiotic surface, with some exhibiting resistance to multiple antimicrobials. Potential as a reservoir of antimicrobial resistance genes may be another hazard of biofilms in food-processing plants. As a result, future strategies to control these pathogens may include measures to prevent biofilms.}, } @article {pmid27023099, year = {2016}, author = {Grillo-Puertas, M and Rintoul, MR and Rapisarda, VA}, title = {PhoB activation in non-limiting phosphate condition by the maintenance of high polyphosphate levels in the stationary phase inhibits biofilm formation in Escherichia coli.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {6}, pages = {1000-1008}, doi = {10.1099/mic.0.000281}, pmid = {27023099}, issn = {1465-2080}, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/metabolism ; Cyclic GMP/analogs & derivatives/biosynthesis ; Enzyme Activation ; Escherichia coli/growth & development/*metabolism ; Gene Expression Regulation, Bacterial/genetics ; Homoserine/analogs & derivatives/biosynthesis ; Lactones ; Organophosphates/*metabolism ; Polyphosphates/*metabolism ; Quorum Sensing/genetics/physiology ; Signal Transduction ; }, abstract = {Polyphosphate (polyP) degradation in Escherichia coli stationary phase triggers biofilm formation via the LuxS quorum sensing system. In media containing excess of phosphate (Pi), high polyP levels are maintained in the stationary phase with the consequent inhibition of biofilm formation. The transcriptional-response regulator PhoB, which is activated under Pi limitation, is involved in the inhibition of biofilm formation in several bacterial species. In the current study, we report, for the first time, we believe that E. coli PhoB can be activated in non-limiting Pi conditions, leading to inhibition of biofilm formation. In fact, PhoB was activated when high polyP levels were maintained in the stationary phase, whereas it remained inactive when the polymer was degraded or absent. PhoB activation was mediated by acetyl phosphate with the consequent repression of biofilm formation owing to the downregulation of c-di-GMP synthesis and the inhibition of autoinducer-2 production. These results allowed us to propose a model showing that PhoB is a component in the signal cascade regulating biofilm formation triggered by fluctuations of polyP levels in E. coli cells during stationary phase.}, } @article {pmid27021328, year = {2016}, author = {da Silva, AR and de Andrade Neto, JB and da Silva, CR and Campos, Rde S and Costa Silva, RA and Freitas, DD and do Nascimento, FB and de Andrade, LN and Sampaio, LS and Grangeiro, TB and Magalhães, HI and Cavalcanti, BC and de Moraes, MO and Nobre Júnior, HV}, title = {Berberine Antifungal Activity in Fluconazole-Resistant Pathogenic Yeasts: Action Mechanism Evaluated by Flow Cytometry and Biofilm Growth Inhibition in Candida spp.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {6}, pages = {3551-3557}, pmid = {27021328}, issn = {1098-6596}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Berberine/adverse effects/*pharmacology ; Biofilms/growth & development ; Candida/classification/*drug effects/genetics ; Candidiasis/*drug therapy/microbiology ; Cell Line ; Cell Proliferation ; Cryptococcosis/*drug therapy/microbiology ; Cryptococcus neoformans/classification/*drug effects/genetics ; DNA, Fungal/genetics ; Drug Resistance, Fungal ; Fluconazole/adverse effects/*pharmacology ; Humans ; L Cells ; Mice ; Microbial Sensitivity Tests ; Mitochondrial Membranes/drug effects ; Molecular Typing ; Mycological Typing Techniques ; }, abstract = {The incidence of fungal infections and, in particular, the incidence of fungal antibiotic resistance, which is associated with biofilm formation, have significantly increased, contributing to morbidity and mortality. Thus, new therapeutic strategies need to be developed. In this context, natural products have emerged as a major source of possible antifungal agents. Berberine is a protoberberine-type isoquinoline alkaloid isolated from the roots, rhizomes, and stem bark of natural herbs, such as Berberis aquifolium, Berberis vulgaris, Berberis aristata, and Hydrastis canadensis, and of Phellodendron amurense Berberine has been proven to have broad antibacterial and antifungal activity. In the present study, the potential antifungal effect of berberine against fluconazole-resistant Candida and Cryptococcus neoformans strains, as well as against the biofilm form of Candida spp., was assessed. The antifungal effect of berberine was determined by a broth microdilution method (the M27-A3 method of the Clinical and Laboratory Standards Institute) and flow cytometry techniques, in which the probable mechanism of action of the compound was also assessed. For biofilm assessment, a colorimetric 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to determine the susceptibility of sessile cells. The isolates used in the study belonged to the Laboratory of Bioprospection and Experiments in Yeast (LABEL) of the Federal University of Ceará. After 24 and 72 h, fluconazole-resistant Candida and Cryptococcus neoformans strains showed berberine MICs equal to 8 μg/ml and 16 μg/ml, respectively. Cytometric analysis showed that treatment with berberine caused alterations to the integrity of the plasma and mitochondrial membranes and DNA damage, which led to cell death, probably by apoptosis. Assessment of biofilm-forming isolates after treatment showed statistically significant reductions in biofilm cell activity (P < 0.001).}, } @article {pmid27021323, year = {2016}, author = {Marcos-Zambrano, LJ and Gómez-Perosanz, M and Escribano, P and Zaragoza, O and Bouza, E and Guinea, J}, title = {Biofilm Production and Antibiofilm Activity of Echinocandins and Liposomal Amphotericin B in Echinocandin-Resistant Yeast Species.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {6}, pages = {3579-3586}, pmid = {27021323}, issn = {1098-6596}, mesh = {Amphotericin B/*pharmacology ; Anidulafungin ; Antifungal Agents/*pharmacology ; Biofilms/drug effects/*growth & development ; Candida/classification/drug effects/*growth & development/isolation & purification ; Candidiasis/*drug therapy/microbiology ; Caspofungin ; Drug Resistance, Fungal/genetics ; Echinocandins/*pharmacology ; Glucosyltransferases/genetics ; Humans ; Lipopeptides/*pharmacology ; Micafungin ; Microbial Sensitivity Tests ; }, abstract = {The echinocandins and liposomal amphotericin B are active against biofilm produced by echinocandin-susceptible Candida strains. However, few data have been reported on the production of biofilm by echinocandin-resistant isolates and their antifungal susceptibility. We studied the production of biofilm by fks mutant Candida strains and intrinsically echinocandin-resistant non-Candida isolates and the susceptibility of both entities to liposomal amphotericin B and echinocandins. We analyzed the production of biofilm by isolates from patients with fungemia (fks mutant Candida, n = 5; intrinsically echinocandin-resistant non-Candida, n = 12; and Candida wild type, n = 10). Biofilm formation was measured to classify strains according to biomass (crystal violet assay) and metabolic activity (XTT reduction assay). Preformed biofilms were tested against liposomal amphotericin B, caspofungin, micafungin, and anidulafungin. The sessile MIC was defined as the antifungal concentration yielding a 50% or 80% reduction in the metabolic activity of the biofilm compared to that of the growth control (SMIC50 and SMIC80, respectively). fks mutant Candida isolates formed biofilms in a fashion similar to that of Candida wild-type strains. The echinocandins had the highest activity against biofilms formed by wild-type Candida isolates, followed by fks mutant Candida isolates and non-Candida isolates. Liposomal amphotericin B had the highest activity against fks mutant Candida biofilms. The formation of biofilm by echinocandin-resistant strains was similar to that of wild-type strains, although resistance to echinocandins remained high.}, } @article {pmid27020951, year = {2016}, author = {Brian-Jaisson, F and Molmeret, M and Fahs, A and Guentas-Dombrowsky, L and Culioli, G and Blache, Y and Cérantola, S and Ortalo-Magné, A}, title = {Characterization and anti-biofilm activity of extracellular polymeric substances produced by the marine biofilm-forming bacterium Pseudoalteromonas ulvae strain TC14.}, journal = {Biofouling}, volume = {32}, number = {5}, pages = {547-560}, doi = {10.1080/08927014.2016.1164845}, pmid = {27020951}, issn = {1029-2454}, mesh = {Biofilms/*drug effects ; Microscopy, Atomic Force ; Polysaccharides, Bacterial/chemistry/isolation & purification/*pharmacology ; Pseudoalteromonas/*metabolism ; *Water Microbiology ; }, abstract = {This study investigated soluble (Sol-EPS), loosely bound (LB-EPS), and tightly bound extracellular polymeric substances (TB-EPS) harvested from biofilm and planktonic cultures of the marine bacterium Pseudoalteromonas ulvae TC14. The aim of the characterization (colorimetric methods, FTIR, GC-MS, NMR, HPGPC, and AFM analyses) was to identify new anti-biofilm compounds; activity was assessed using the BioFilm Ring Test®. A step-wise separation of EPS was designed, based on differences in water-solubility and acidity. An acidic fraction was isolated from TB-EPS, which strongly inhibited biofilm formation by marine bacterial strains in a concentration-dependent manner. The main constituents of this fraction were characterized as two glucan-like polysaccharides. An active poly(glutamyl-glutamate) fraction was also recovered from TB-EPS. The distribution of these key EPS components in Sol-EPS, LB-EPS, and TB-EPS was distinct and differed quantitatively in biofilm vs planktonic cultures. The anti-biofilm potential of the fractions emphasizes the putative antifouling role of EPS in the environment.}, } @article {pmid27020873, year = {2016}, author = {Mártha, K and Lőrinczi, L and Bică, C and Gyergyay, R and Petcu, B and Lazăr, L}, title = {Assessment of Periodontopathogens in Subgingival Biofilm of Banded and Bonded Molars in Early Phase of Fixed Orthodontic Treatment.}, journal = {Acta microbiologica et immunologica Hungarica}, volume = {63}, number = {1}, pages = {103-113}, doi = {10.1556/030.63.2016.1.8}, pmid = {27020873}, issn = {1217-8950}, mesh = {Adolescent ; *Biofilms ; Capnocytophaga/isolation & purification/*physiology ; Child ; Dental Plaque/*microbiology/therapy ; Eikenella corrodens/isolation & purification/*physiology ; Female ; Fusobacterium nucleatum/isolation & purification/*physiology ; Humans ; Male ; Molar/*microbiology ; Orthodontics ; }, abstract = {To assess the prevalence and occurrence of eleven periodontopathogens in subgingival biofilm of banded and bonded molars during the first period of fixed orthodontic treatment. Subjects were selected from patients referred to orthodontic treatment and were divided in two groups: group A comprised fifteen patients (14.4±2.45 years of age) who received orthodontic bands on first permanent molars and group B of ten patients (15.7±1.87 years of age) with directly bonded tubes on the labial surface of the same teeth. Subgingival sample collection was performed before bands and tubes application and 4-7 weeks after attachment placement. DNA-strip tehnique was used to assess the presence of eleven putative periodontopathogens at each time point. Fusobacterium nucleatum, Eikenella corrodens and Capnocytophaga spp. were found in a large number of samples, other periodontopathogens were present in a smaller rate. The 4-7 weeks after attachment placement a slight increase of putative species was observed in both groups. The presence of orthodontic tubes and bands influence the accumulation and composition of subgingival microbiota. Higher level of oral hygiene should be achieved before and during orthodontic treatment in order to prevent any side effects on periodontal tissues.}, } @article {pmid27020154, year = {2016}, author = {Martins, CHG and Pires, RH and Cunha, AO and Pereira, CAM and Singulani, JL and Abrão, F and Moraes, T and Mendes-Giannini, MJS}, title = {Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.}, journal = {Fungal biology}, volume = {120}, number = {4}, pages = {530-537}, doi = {10.1016/j.funbio.2016.01.013}, pmid = {27020154}, issn = {1878-6146}, mesh = {Biofilms/*growth & development ; Candida/classification/growth & development/*isolation & purification/*physiology ; Colony Count, Microbial ; Dental Prosthesis/*microbiology ; Formazans/analysis ; Humans ; *Microbial Interactions ; Temperature ; Tetrazolium Salts/metabolism ; }, abstract = {Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p < 0.001) than non-albicans Candida strains, after 6 h 37 °C. The total C. albicans CFU from a dual-species biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm.}, } @article {pmid27019560, year = {2016}, author = {Azevedo, MM and Almeida, CA and Chaves, FC and Rodrigues, IA and Bizzo, HR and Alviano, CS and Alviano, DS}, title = {7-hydroxycalamenene Effects on Secreted Aspartic Proteases Activity and Biofilm Formation of Candida spp.}, journal = {Pharmacognosy magazine}, volume = {12}, number = {45}, pages = {36-40}, pmid = {27019560}, issn = {0973-1296}, abstract = {BACKGROUND: The 7-hydroxycalamenenene-rich essential oil (EO) obtained from the leaves of Croton cajucara (red morphotype) have been described as active against bacteria, protozoa, and fungi species. In this work, we aimed to evaluate the effectiveness of 7-hydroxycalamenenene against Candida albicans and nonalbicans species.

MATERIALS AND METHODS: C. cajucara EO was obtained by hydrodistillation and its major compound, 7-hydroxycalamenene, was purified using preparative column chromatography. The anti-candidal activity was investigated by minimum inhibitory concentration (MIC) and secreted aspartic proteases (SAP) and biofilm inhibition assays.

RESULTS: 7-hydroxycalamenene (98% purity) displayed anti-candidal activity against all Candida species tested. Higher activity was observed against Candida dubliniensis, Candida parapsilosis and Candida albicans, showing MIC values ranging from 39.06 μg/ml to 78.12 μg/ml. The purified 7-hydroxycalamenene was able to inhibit 58% of C. albicans ATCC 36801 SAP activity at MIC concentration (pH 7.0). However, 7-hydroxycalamenene demonstrated poor inhibitory activity on C. albicans ATCC 10231 biofilm formation even at the highest concentration tested (2500 μg/ml).

CONCLUSION: The bioactive potential of 7-hydroxycalamenene against planktonic Candida spp. further supports its use for the development of antimicrobials with anti-candidal activity.

SUMMARY: Croton cajucara Benth. essential oil provides high amounts of 7-hydroxycalamenene7-Hydroxycalameneneisolated from C. cajucarais active against Candida spp7-Hydroxycalameneneinhibits C. albicans aspartic protease activity7-Hydroxycalamenene was not active against C. albicans biofilm formation. Figure.}, } @article {pmid27015018, year = {2016}, author = {Herrera, A and Vu, BG and Stach, CS and Merriman, JA and Horswill, AR and Salgado-Pabón, W and Schlievert, PM}, title = {Staphylococcus aureus β-Toxin Mutants Are Defective in Biofilm Ligase and Sphingomyelinase Activity, and Causation of Infective Endocarditis and Sepsis.}, journal = {Biochemistry}, volume = {55}, number = {17}, pages = {2510-2517}, pmid = {27015018}, issn = {1520-4995}, support = {P30 DK054759/DK/NIDDK NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Animals ; Bacterial Toxins/*adverse effects/chemistry/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Endocarditis/enzymology/*etiology/pathology ; Female ; Hemolysin Proteins/*adverse effects/chemistry/genetics/metabolism ; Ligases/*deficiency ; Male ; Protein Conformation ; Rabbits ; Sepsis/enzymology/*etiology/pathology ; Sphingomyelin Phosphodiesterase/adverse effects/chemistry/*deficiency/genetics/metabolism ; Staphylococcal Infections/complications/microbiology ; Staphylococcus aureus/*enzymology/genetics ; }, abstract = {β-Toxin is an important virulence factor of Staphylococcus aureus, contributing to colonization and development of disease [Salgado-Pabon, W., et al. (2014) J. Infect. Dis. 210, 784-792; Huseby, M. J., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 14407-14412; Katayama, Y., et al. (2013) J. Bacteriol. 195, 1194-1203]. This cytotoxin has two distinct mechanisms of action: sphingomyelinase activity and DNA biofilm ligase activity. However, the distinct mechanism that is most important for its role in infective endocarditis is unknown. We characterized the active site of β-toxin DNA biofilm ligase activity by examining deficiencies in site-directed mutants through in vitro DNA precipitation and biofilm formation assays. Possible conformational changes in mutant structure compared to that of wild-type toxin were assessed preliminarily by trypsin digestion analysis, retention of sphingomyelinase activity, and predicted structures based on the native toxin structure. We addressed the contribution of each mechanism of action to producing infective endocarditis and sepsis in vivo in a rabbit model. The H289N β-toxin mutant, lacking sphingomyelinase activity, exhibited lower sepsis lethality and infective endocarditis vegetation formation compared to those of the wild-type toxin. β-Toxin mutants with disrupted biofilm ligase activity did not exhibit decreased sepsis lethality but were deficient in infective endocarditis vegetation formation compared to the wild-type protein. Our study begins to characterize the DNA biofilm ligase active site of β-toxin and suggests β-toxin functions importantly in infective endocarditis through both of its mechanisms of action.}, } @article {pmid27014256, year = {2016}, author = {, }, title = {Erratum: Exposure of E. coli to DNA-Methylating Agents Impairs Biofilm Formation and Invasion of Eukaryotic Cells via Down Regulation of the N-Acetylneuraminate Lyase NanA.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {383}, doi = {10.3389/fmicb.2015.00383}, pmid = {27014256}, issn = {1664-302X}, abstract = {[This corrects the article on p. 147 in vol. 7, PMID: 26904018.].}, } @article {pmid27014218, year = {2016}, author = {Liu, L and Fang, H and Yang, H and Zhang, Y and Han, Y and Zhou, D and Yang, R}, title = {CRP Is an Activator of Yersinia pestis Biofilm Formation that Operates via a Mechanism Involving gmhA and waaAE-coaD.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {295}, pmid = {27014218}, issn = {1664-302X}, abstract = {gmhA encodes a phosphoheptose isomerase that catalyzes the biosynthesis of heptose, a conserved component of lipopolysaccharide (LPS). GmhA plays an important role in Yersinia pestis biofilm blockage in the flea gut. waaA, waaE, and coaD constitute a three-gene operon waaAE-coaD in Y. pestis. waaA encodes a transferase that is responsible for binding lipid-A to the core oligosaccharide of LPS. WaaA is a key determinant in Y. pestis biofilm formation, and the waaA expression is positively regulated by the two-component regulatory system PhoP/PhoQ. WaaE is involved in LPS modification and is necessary for Y. pestis biofilm production. In this study, the biofilm-related phenotypic assays indicate that the global regulator CRP stimulates Y. pestis biofilm formation in vitro and on nematodes, while it has no regulatory effect on the biosynthesis of the biofilm-signaling molecular 3',5'-cyclic diguanosine monophosphate. Further gene regulation experiments disclose that CRP does not regulate the hms genes at the transcriptional level but directly promotes the gmhA transcription and indirectly activates the waaAE-coaD transcription through directly acting on phoPQ-YPO1632. Thus, it is speculated that CRP-mediated carbon catabolite regulation of Y. pestis biofilm formation depends on the CRP-dependent carbon source metabolic pathways of the biosynthesis, modification, and transportation of biofilm exopolysaccharide.}, } @article {pmid27013931, year = {2016}, author = {Stipetic, LH and Dalby, MJ and Davies, RL and Morton, FR and Ramage, G and Burgess, KE}, title = {A novel metabolomic approach used for the comparison of Staphylococcus aureus planktonic cells and biofilm samples.}, journal = {Metabolomics : Official journal of the Metabolomic Society}, volume = {12}, number = {}, pages = {75}, pmid = {27013931}, issn = {1573-3882}, abstract = {INTRODUCTION: Bacterial cell characteristics change significantly during differentiation between planktonic and biofilm states. While established methods exist to detect and identify transcriptional and proteomic changes, metabolic fluctuations that distinguish these developmental stages have been less amenable to investigation.

OBJECTIVES: The objectives of the study were to develop a robust reproducible sample preparation methodology for high throughput biofilm analysis and to determine differences between Staphylococcus aureus in planktonic and biofilm states.

METHODS: The method uses bead beating in a chloroform/methanol/water extraction solvent to both disrupt cells and quench metabolism. Verification of the method was performed using liquid-chromatography-mass spectrometry. Raw mass-spectrometry data was analysed using an in-house bioinformatics pipe-line incorporating XCMS, MzMatch and in-house R-scripts, with identifications matched to internal standards and metabolite data-base entries.

RESULTS: We have demonstrated a novel mechanical bead beating method that has been optimised for the extraction of the metabolome from cells of a clinical Staphylococcus aureus strain existing in a planktonic or biofilm state. This high-throughput method is fast and reproducible, allowing for direct comparison between different bacterial growth states. Significant changes in arginine biosynthesis were identified between the two cell populations.

CONCLUSIONS: The method described herein represents a valuable tool in studying microbial biochemistry at a molecular level. While the methodology is generally applicable to the lysis and extraction of metabolites from Gram positive bacteria, it is particularly applicable to biofilms. Bacteria that exist as a biofilm are shown to be highly distinct metabolically from their 'free living' counterparts, thus highlighting the need to study microbes in different growth states. Metabolomics can successfully distinguish between a planktonic and biofilm growth state. Importantly, this study design, incorporating metabolomics, could be optimised for studying the effects of antimicrobials and drug modes of action, potentially providing explanations and mechanisms of antibiotic resistance and to help devise new antimicrobials.}, } @article {pmid27013841, year = {2016}, author = {Gupta, R and Malik, A and Rizvi, M and Ahmed, SM}, title = {Incidence of Multidrug-Resistant Pseudomonas Spp. in ICU Patients with Special Reference to ESBL, AMPC, MBL and Biofilm Production.}, journal = {Journal of global infectious diseases}, volume = {8}, number = {1}, pages = {25-31}, pmid = {27013841}, issn = {0974-777X}, abstract = {BACKGROUND: Multidrug-resistant (MDR) Pseudomonas spp. have been reported to be the important cause of ICU infections. The appearance of ESBL, AmpC and MBL genes and their spread among bacterial pathogens is a matter of great concern. Biofilm production also attributes to antimicrobial resistance due to close cell to cell contact that permits bacteria to more effectively transfer plasmids to one another. This study aimed at determining the incidence of ESBL, AmpC, MBL and biofilm producing Pseudomonas spp. in ICU patients.

MATERIAL AND METHODS: The clinical specimens were collected aseptically from 150 ICU patients from February 2012 to October 2013. Identification and antimicrobial susceptibility was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. ESBLs and AmpC were detected phenotypically and genotypically. MBL was detected by modified Hodge and imipenem-EDTA double-disk synergy test.

RESULTS: Pseudomonas spp. 35(28%) were the most prevalent pathogen in ICU infections. Multidrug resistance and biofilm production was observed in 80.1% and 60.4% isolates, respectively. Prevalence of ESBL, AmpC and MBL was 22.9%, 42.8% and 14.4%, respectively. The average hospital stay was 25 days and was associated with 20% mortality.

CONCLUSIONS: A regular surveillance is required to detect ESBL, AmpC and MBL producers especially in ICU patients. Carbapenems should be judiciously used to prevent their spread. The effective antibiotics, such as fluoroquinolones and piperacillin-tazobactum should be used after sensitivity testing.}, } @article {pmid27013838, year = {2016}, author = {Farahani, A}, title = {State of Globe: Enterococci: Virulence Factors and Biofilm Formation.}, journal = {Journal of global infectious diseases}, volume = {8}, number = {1}, pages = {1-2}, pmid = {27013838}, issn = {0974-777X}, } @article {pmid27012918, year = {2016}, author = {Duarte, A and Ferreira, S and Almeida, S and Domingues, FC}, title = {Clinical isolates of Acinetobacter baumannii from a Portuguese hospital: PFGE characterization, antibiotic susceptibility and biofilm-forming ability.}, journal = {Comparative immunology, microbiology and infectious diseases}, volume = {45}, number = {}, pages = {29-33}, doi = {10.1016/j.cimid.2016.02.002}, pmid = {27012918}, issn = {1878-1667}, mesh = {Acinetobacter Infections/epidemiology/*microbiology/prevention & control ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification/*physiology ; Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Cross Infection/*microbiology ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Emergency Service, Hospital ; Humans ; Portugal/epidemiology ; Urine/microbiology ; }, abstract = {Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections that in addition has shown an increasing resistance to antibiotics. In this work the genetic diversity of A. baumannii isolates from a Portuguese hospital, their antibiotic resistance profiles and ability to form biofilms was studied. Seventy-nine clinical A. baumannii isolates were characterized by pulsed-field gel electrophoresis (PFGE) with 9 different PFGE profiles being obtained. Concerning the antimicrobial susceptibility, all A. baumannii isolates were resistant to 12 of the 17 tested antibiotics and classified as multidrug-resistant (MDR). In addition, 74.7% of the isolates showed biofilm formation ability, however no statistical significance with antibiotic resistance was observed. In contrast, urine samples isolates were more likely to form biofilms than strains isolated from other sources. Our findings highlight the high number of MDR A. baumannii isolates and the importance of the formation of biofilms as a potential virulence factor.}, } @article {pmid27008278, year = {2016}, author = {Yokoi, KJ and Kuzuwa, S and Iwasaki, S and Yamakawa, A and Taketo, A and Kodaira, K}, title = {Aureolysin of Staphylococcus warneri M accelerates its proteolytic cascade, and participates in biofilm formation.}, journal = {Bioscience, biotechnology, and biochemistry}, volume = {80}, number = {6}, pages = {1238-1242}, doi = {10.1080/09168451.2016.1148576}, pmid = {27008278}, issn = {1347-6947}, mesh = {Bacterial Proteins/*genetics/metabolism ; Biofilms/growth & development ; Cloning, Molecular ; Cysteine Proteases/*genetics/metabolism ; Escherichia coli/genetics/metabolism ; *Gene Expression Regulation, Bacterial ; Metalloendopeptidases/*genetics/metabolism ; Proteolysis ; Recombinant Proteins/genetics/metabolism ; Sequence Analysis, DNA ; Serine Proteases/*genetics/metabolism ; Staphylococcus/*genetics/growth & development/metabolism ; }, abstract = {The aureolysin (Aur) gene of S. warneri M (aurWM) was cloned and sequenced. Analyses of the aurWM-inactivated mutant (S. warneri Mau) suggested that AurWM was probably associated with efficient processing of the PROM protease (homolog of V8/SspA serine protease), whereas considerable amount of mature-PROC protease (homolog of SspB cysteine protease) accumulated without AurWM. Additionally, AurWM appeared to affect biofilm formation in an uncertain suppressive way.}, } @article {pmid27006463, year = {2016}, author = {Kragh, KN and Hutchison, JB and Melaugh, G and Rodesney, C and Roberts, AE and Irie, Y and Jensen, PØ and Diggle, SP and Allen, RJ and Gordon, V and Bjarnsholt, T}, title = {Role of Multicellular Aggregates in Biofilm Formation.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00237}, pmid = {27006463}, issn = {2150-7511}, mesh = {Biofilms/*growth & development ; *Cell Adhesion ; Computer Simulation ; Pseudomonas aeruginosa/*physiology ; }, abstract = {UNLABELLED: In traditional models ofin vitrobiofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development ofPseudomonas aeruginosabiofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation.

IMPORTANCE: During the past decades, there has been a consensus around the model of development of a biofilm, involving attachment of single planktonic bacterial cells to a surface and the subsequent development of a mature biofilm. This study presents results that call for a modification of this rigorous model. We show how free floating biofilm aggregates can have a profound local effect on biofilm development when attaching to a surface. Our findings show that an aggregate landing on a surface will eventually outcompete the biofilm population arising from single cells attached around the aggregate and dominate the local biofilm development. These results point to a regime where preformed biofilm aggregates may have a fitness advantage over planktonic cells when it comes to accessing nutrients. Our findings add to the increasingly prominent comprehension that biofilm lifestyle is the default for bacteria and that planktonic single cells may be only a transition state at the most.}, } @article {pmid27005008, year = {2016}, author = {Granato, LM and Picchi, SC and Andrade, Mde O and Takita, MA and de Souza, AA and Wang, N and Machado, MA}, title = {The ATP-dependent RNA helicase HrpB plays an important role in motility and biofilm formation in Xanthomonas citri subsp. citri.}, journal = {BMC microbiology}, volume = {16}, number = {}, pages = {55}, pmid = {27005008}, issn = {1471-2180}, mesh = {5' Untranslated Regions ; Bacterial Adhesion ; Bacterial Proteins/genetics/metabolism ; Biofilms/*growth & development ; Citrus/microbiology ; Fimbriae, Bacterial/genetics ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Plant Diseases/microbiology ; Plant Leaves/microbiology ; RNA Helicases/*genetics/*metabolism ; Virulence ; Xanthomonas/enzymology/*pathogenicity/*physiology ; }, abstract = {BACKGROUND: RNA helicases are enzymes that catalyze the separation of double-stranded RNA (dsRNA) using the free energy of ATP binding and hydrolysis. DEAD/DEAH families participate in many different aspects of RNA metabolism, including RNA synthesis, RNA folding, RNA-RNA interactions, RNA localization and RNA degradation. Several important bacterial DEAD/DEAH-box RNA helicases have been extensively studied. In this study, we characterize the ATP-dependent RNA helicase encoded by the hrpB (XAC0293) gene using deletion and genetic complementation assays. We provide insights into the function of the hrpB gene in Xanthomonas citri subsp. citri by investigating the roles of hrpB in biofilm formation on abiotic surfaces and host leaves, cell motility, host virulence of the citrus canker bacterium and growth in planta.

RESULTS: The hrpB gene is highly conserved in the sequenced strains of Xanthomonas. Mutation of the hrpB gene (∆hrpB) resulted in a significant reduction in biofilms on abiotic surfaces and host leaves. ∆hrpB also exhibited increased cell dispersion on solid medium plates. ∆hrpB showed reduced adhesion on biotic and abiotic surfaces and delayed development in disease symptoms when sprayed on susceptible citrus leaves. Quantitative reverse transcription-PCR assays indicated that deletion of hrpB reduced the expression of four type IV pili genes. The transcriptional start site of fimA (XAC3241) was determined using rapid amplification of 5'-cDNA Ends (5'RACE). Based on the results of fimA mRNA structure predictions, the fimA 5' UTR may contain three different loops. HrpB may be involved in alterations to the structure of fimA mRNA that promote the stability of fimA RNA.

CONCLUSIONS: Our data show that hrpB is involved in adherence of Xanthomonas citri subsp. citri to different surfaces. In addition, to the best of our knowledge, this is the first time that a DEAH RNA helicase has been implicated in the regulation of type IV pili in Xanthomonas.}, } @article {pmid27004424, year = {2016}, author = {Hermans, K and Roberfroid, S and Thijs, IM and Kint, G and De Coster, D and Marchal, K and Vanderleyden, J and De Keersmaecker, SC and Steenackers, HP}, title = {FabR regulates Salmonella biofilm formation via its direct target FabB.}, journal = {BMC genomics}, volume = {17}, number = {}, pages = {253}, pmid = {27004424}, issn = {1471-2164}, mesh = {3-Oxoacyl-(Acyl-Carrier-Protein) Synthase ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Chromatin Immunoprecipitation ; Escherichia coli Proteins ; Fatty Acid Synthase, Type II/genetics/*metabolism ; Fatty Acids, Unsaturated/*biosynthesis ; Gene Expression Regulation, Bacterial ; Promoter Regions, Genetic ; Regulon ; Salmonella typhimurium/*genetics/growth & development ; Transcription Factors/genetics/*metabolism ; }, abstract = {BACKGROUND: Biofilm formation is an important survival strategy of Salmonella in all environments. By mutant screening, we showed a knock-out mutant of fabR, encoding a repressor of unsaturated fatty acid biosynthesis (UFA), to have impaired biofilm formation. In order to unravel how this regulator impinges on Salmonella biofilm formation, we aimed at elucidating the S. Typhimurium FabR regulon. Hereto, we applied a combinatorial high-throughput approach, combining ChIP-chip with transcriptomics.

RESULTS: All the previously identified E. coli FabR transcriptional target genes (fabA, fabB and yqfA) were shown to be direct S. Typhimurium FabR targets as well. As we found a fabB overexpressing strain to partly mimic the biofilm defect of the fabR mutant, the effect of FabR on biofilms can be attributed at least partly to FabB, which plays a key role in UFA biosynthesis. Additionally, ChIP-chip identified a number of novel direct FabR targets (the intergenic regions between hpaR/hpaG and ddg/ydfZ) and yet putative direct targets (i.a. genes involved in tRNA metabolism, ribosome synthesis and translation). Next to UFA biosynthesis, a number of these direct targets and other indirect targets identified by transcriptomics (e.g. ribosomal genes, ompA, ompC, ompX, osmB, osmC, sseI), could possibly contribute to the effect of FabR on biofilm formation.

CONCLUSION: Overall, our results point at the importance of FabR and UFA biosynthesis in Salmonella biofilm formation and their role as potential targets for biofilm inhibitory strategies.}, } @article {pmid27004423, year = {2017}, author = {Metcalf, DG and Parsons, D and Bowler, PG}, title = {Clinical safety and effectiveness evaluation of a new antimicrobial wound dressing designed to manage exudate, infection and biofilm.}, journal = {International wound journal}, volume = {14}, number = {1}, pages = {203-213}, pmid = {27004423}, issn = {1742-481X}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Infective Agents/*therapeutic use ; *Bandages ; Biofilms/*drug effects ; Carboxymethylcellulose Sodium/*therapeutic use ; Exudates and Transudates/*drug effects ; Female ; Humans ; Male ; Middle Aged ; Silver/*therapeutic use ; Treatment Outcome ; United Kingdom ; Wound Healing ; Wounds and Injuries/*drug therapy/microbiology ; Young Adult ; }, abstract = {The objective of this work was to evaluate the safety and effectiveness of a next-generation antimicrobial wound dressing (NGAD; AQUACEL[®] Ag+ Extra™ dressing) designed to manage exudate, infection and biofilm. Clinicians were requested to evaluate the NGAD within their standard protocol of care for up to 4 weeks, or as long as deemed clinically appropriate, in challenging wounds that were considered to be impeded by suspected biofilm or infection. Baseline information and post-evaluation dressing safety and effectiveness data were recorded using standardised evaluation forms. This data included wound exudate levels, wound bed appearance including suspected biofilm, wound progression, skin health and dressing usage. A total of 112 wounds from 111 patients were included in the evaluations, with a median duration of 12 months, and biofilm was suspected in over half of all wounds (54%). After the introduction of the NGAD, exudate levels had shifted from predominantly high or moderate to low or moderate levels, while biofilm suspicion fell from 54% to 27% of wounds. Wound bed coverage by tissue type was generally shifted from sloughy or suspected biofilm towards predominantly granulation tissue after the inclusion of the NGAD. Stagnant (65%) and deteriorating wounds (27%) were shifted to improved (65%) or healed wounds (13%), while skin health was also reported to have improved in 63% of wounds. High levels of clinician satisfaction with the dressing effectiveness and change frequency were accompanied by a low number of dressing-related adverse events (n = 3; 2·7%) and other negative observations or comments. This clinical user evaluation supports the growing body of evidence that the anti-biofilm technology in the NGAD results in a safe and effective dressing for the management of a variety of challenging wound types.}, } @article {pmid27001253, year = {2016}, author = {Tada, A and Nakayama-Imaohji, H and Yamasaki, H and Hasibul, K and Yoneda, S and Uchida, K and Nariya, H and Suzuki, M and Miyake, M and Kuwahara, T}, title = {Cleansing effect of acidic L-arginine on human oral biofilm.}, journal = {BMC oral health}, volume = {16}, number = {}, pages = {40}, pmid = {27001253}, issn = {1472-6831}, mesh = {Arginine/*pharmacology ; Biofilms/*drug effects ; Dental Caries/prevention & control ; Dental Plaque/*prevention & control ; Humans ; Saliva ; }, abstract = {BACKGROUND: Dental plaque formed on tooth surfaces is a complex ecosystem composed of diverse oral bacteria and salivary components. Accumulation of dental plaque is a risk factor for dental caries and periodontal diseases. L-arginine has been reported to decrease the risk for dental caries by elevating plaque pH through the activity of arginine deiminase in oral bacteria. Here we evaluated the potential of L-arginine to remove established oral biofilms.

METHODS: Biofilms were formed using human saliva mixed with Brain Heart Infusion broth supplemented with 1 % sucrose in multi-well plates or on plastic discs. After washing the biofilms with saline, citrate (10 mM, pH3.5), or L-arginine (0.5 M, pH3.5), the retained biofilms were analyzed by crystal violet staining, scanning electron microscopy, and Illumina-based 16S rDNA sequencing.

RESULTS: Washing with acidic L-arginine detached oral biofilms more efficiently than saline and significantly reduced biofilm mass retained in multi-well plates or on plastic discs. Illumina-based microbiota analysis showed that citrate (pH3.5) preferentially washed out Streptococcus from mature oral biofilm, whereas acidic L-arginine prepared with 10 mM citrate buffer (pH3.5) non-specifically removed microbial components of the oral biofilm.

CONCLUSIONS: Acidic L-arginine prepared with citrate buffer (pH3.5) effectively destabilized and removed mature oral biofilms. The acidic L-arginine solution described here could be used as an additive that enhances the efficacy of mouth rinses used in oral hygiene.}, } @article {pmid27000771, year = {2017}, author = {Schmidt, KE and Auschill, TM and Heumann, C and Frankenberger, R and Eick, S and Sculean, A and Arweiler, NB}, title = {Influence of different instrumentation modalities on the surface characteristics and biofilm formation on dental implant neck, in vitro.}, journal = {Clinical oral implants research}, volume = {28}, number = {4}, pages = {483-490}, doi = {10.1111/clr.12823}, pmid = {27000771}, issn = {1600-0501}, mesh = {Adult ; Aged ; Alveolar Ridge Augmentation ; *Biofilms ; Case-Control Studies ; *Dental Implant-Abutment Design ; *Dental Implants ; Dental Plaque Index ; *Dental Prosthesis Design ; Dental Restoration Failure ; Female ; Follow-Up Studies ; Humans ; In Vitro Techniques ; Male ; Middle Aged ; Periodontal Index ; Postoperative Complications/etiology ; Surface Properties ; *Surgical Instruments ; }, abstract = {OBJECTIVES: To evaluate surface characteristics of implants after using different instruments and biofilm formation following instrumentation.

MATERIAL AND METHODS: Thirty-five commercially available dental implants were embedded into seven plastic models, attached to a phantom head and randomly assigned to seven instrumentation groups: (1) stainless steel (SSC) or (2) titanium curettes (TC); air-polisher using glycine-based (3) perio (PP) or (4) soft (SP) powders or (5) erythritol powder (EP); and an ultrasonic device using (6) stainless steel (PS) or (7) plastic-coated instruments (PI). Half of each implant neck in each group (n = 5) was treated once (30 s), while the other half was left uninstrumented (control). An eighth (8) treatment group used a bur/polisher to smooth two implants (SM). Following instrumentation implants were rinsed (5 ml Ringer's solution), analysed under a scanning electron microscope (SEM) and subjected twice (separately) to bacterial colonization with Streptococcus gordonii (2 h) and a mixed culture (S. gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, Porphyromonas gingivalis and Tannerella forsythia; 24 h).

RESULTS: Visual assessment of SEM pictures revealed surface modifications (smoothening to roughening) following instrumentation. These alterations differed between the instrument groups and from the control. Quantitative scoring of the photographs revealed that SSC caused a significantly rougher surface compared to other instruments (P < 0.05), except for SP (P = 0.057) and PP (P = 0.108). After bacterial colonization no significant differences (P > 0.05) were evident between instrumented or control surfaces in either culture.

CONCLUSIONS: Overall, no significant differences were observed in the surface characteristics (except for SSC) or bacterial colonization based on one-time instrumentation.}, } @article {pmid27000525, year = {2016}, author = {Das, MC and Sandhu, P and Gupta, P and Rudrapaul, P and De, UC and Tribedi, P and Akhter, Y and Bhattacharjee, S}, title = {Attenuation of Pseudomonas aeruginosa biofilm formation by Vitexin: A combinatorial study with azithromycin and gentamicin.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {23347}, pmid = {27000525}, issn = {2045-2322}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Apigenin/*pharmacology ; Azithromycin/*pharmacology ; *Biofilms ; Gentamicins/*pharmacology ; Mice ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/metabolism ; Quorum Sensing ; }, abstract = {Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combination with azithromycin and gentamicin. Vitexin shows minimum inhibitory concentration (MIC) at 260 μg/ml. It's antibiofilm activity was evaluated by safranin staining, protein extraction, microscopy methods, quantification of EPS and in vivo models using several sub-MIC doses. Various quorum sensing (QS) mediated phenomenon such as swarming motility, azocasein degrading protease activity, pyoverdin and pyocyanin production, LasA and LasB activity of the bacteria were also evaluated. Results showed marked attenuation in biofilm formation and QS mediated phenotype of Pseudomonas aeruginosa in presence of 110 μg/ml vitexin in combination with azithromycin and gentamicin separately. Molecular docking of vitexin with QS associated LuxR, LasA, LasI and motility related proteins showed high and reasonable binding affinity respectively. The study explores the antibiofilm potential of vitexin against P. aeruginosa which can be used as a new antibiofilm agent against microbial biofilm associated pathogenesis.}, } @article {pmid26999597, year = {2016}, author = {Ceotto-Vigoder, H and Marques, SL and Santos, IN and Alves, MD and Barrias, ES and Potter, A and Alviano, DS and Bastos, MC}, title = {Nisin and lysostaphin activity against preformed biofilm of Staphylococcus aureus involved in bovine mastitis.}, journal = {Journal of applied microbiology}, volume = {121}, number = {1}, pages = {101-114}, doi = {10.1111/jam.13136}, pmid = {26999597}, issn = {1365-2672}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Cattle ; Cell Survival/drug effects ; Female ; Lysostaphin/*pharmacology/therapeutic use ; Mastitis, Bovine/*drug therapy ; Microbial Sensitivity Tests/methods ; Nisin/*pharmacology/therapeutic use ; Plankton/drug effects ; Staphylococcal Infections/*drug therapy ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {AIMS: The biofilm produced by Staphylococcus aureus isolates involved in clinical or subclinical bovine mastitis and the activity of nisin and lysostaphin against the preformed biofilm produced by these strains were investigated.

METHODS AND RESULTS: Eighteen strains were tested and all produced biofilm. Eight strains with distinct biofilm composition were selected for the antimicrobial activity assays. The minimal inhibitory concentration of each bacteriocin was determined against the planktonic cells and ranged from 15·6 to 500 μg ml(-1) for nisin, and from 3·9 to 50 μg ml(-1) , for lysostaphin. Lysostaphin treatment (0·4 μg ml(-1)) for 4 h caused a strong Staph. aureus 4181 biofilm detachment and death of the majority of the sessile cells, while nisin treatment (100 μg ml(-1)) for the same time caused only a great reduction in cell viability. Additionally, combination of both bacteriocins for 4 h resulted in significant death of the sessile cells but no biofilm detachment.

CONCLUSIONS: The treatment with lysostaphin alone or in combination with nisin was effective in killing most biofilm sessile cells.

The action of lysostaphin, either alone or in combination with nisin, against established staphylococcal biofilm may represent an alternative to bovine mastitis control. However, the duration of the treatment should be considered for its application so that the best effectiveness can be achieved.}, } @article {pmid26999221, year = {2016}, author = {Nett, JE}, title = {The Host's Reply to Candida Biofilm.}, journal = {Pathogens (Basel, Switzerland)}, volume = {5}, number = {1}, pages = {}, pmid = {26999221}, issn = {2076-0817}, support = {K08 AI108727/AI/NIAID NIH HHS/United States ; }, abstract = {Candida spp. are among the most common nosocomial fungal pathogens and are notorious for their propensity toward biofilm formation. When growing on a medical device or mucosal surface, these organisms reside as communities embedded in a protective matrix, resisting host defenses. The host responds to Candida biofilm by depositing a variety of proteins that become incorporated into the biofilm matrix. Compared to free-floating Candida, leukocytes are less effective against Candida within a biofilm. This review highlights recent advances describing the host's response to Candida biofilms using ex vivo and in vivo models of mucosal and device-associated biofilm infections.}, } @article {pmid26997991, year = {2016}, author = {Li, T and Zhang, L and Han, LI and Wang, G and Yin, P and Li, Z and Zhang, L and Guo, QI and Liu, D and Tang, P}, title = {Early application of negative pressure wound therapy to acute wounds contaminated with Staphylococcus aureus: An effective approach to preventing biofilm formation.}, journal = {Experimental and therapeutic medicine}, volume = {11}, number = {3}, pages = {769-776}, pmid = {26997991}, issn = {1792-0981}, abstract = {Negative pressure wound therapy (NPWT) has been demonstrated to be effective at preventing biofilm-associated infections; however, its role in biofilm prevention is unknown. The present study evaluated the effect of NPWT on biofilm prevention when rapidly initiated following wound contamination. Full-thickness dermal wounds (8 mm) were created in rabbit ears and inoculated with green fluorescent protein-labeled Staphylococcus aureus (S. aureus). At 6 h following inoculation, continuous NPWT at -125 mmHg was initiated, with the wounds on the contralateral ear left untreated in order to serve as self-controls. S. aureus rapidly formed mature biofilms in the wound beds post-inoculation, with a persistent bacterial burden of ~10[5]-10[7] colony-forming units (CFUs)/wound and impaired wound healing. Compared with the untreated group, NPWT resulted in a significant reduction in biofilm matrix, which was verified by scanning electron microscopy and epifluorescence. A reduction in bacterial counts followed (P<0.05) with ~10[3] CFUs/wound on postoperative day 13 and improvement in all healing parameters (P<0.05) relative to control wounds. The results of the present investigation suggest that NPWT is an effective strategy to impeding the formation of S. aureus wound biofilms when initiated rapidly following bacterial contamination. The early application of NPWT, aimed at biofilm prevention, may improve wound care.}, } @article {pmid26997224, year = {2016}, author = {Attaran, B and Falsafi, T and Moghaddam, AN}, title = {Study of biofilm formation in C57Bl/6J mice by clinical isolates of Helicobacter pylori.}, journal = {Saudi journal of gastroenterology : official journal of the Saudi Gastroenterology Association}, volume = {22}, number = {2}, pages = {161-168}, pmid = {26997224}, issn = {1998-4049}, mesh = {Animals ; Bacterial Adhesion ; Biofilms/*growth & development ; Disease Models, Animal ; Female ; Helicobacter Infections/*microbiology ; Helicobacter pylori/isolation & purification/*physiology ; Humans ; Mice ; Mice, Inbred C57BL ; Stomach/microbiology ; }, abstract = {BACKGROUND/AIM: Despite the significant number of studies on H. pylori pathogenesis, not much data has been published concerning its ability to form biofilm in the host stomach. This study aims to evaluate the potential of clinical isolates of H. pylori to form biofilm in C57BL/6J mice model.

MATERIALS AND METHODS: Two strains of H. pylori were selected from a collection of clinical isolates; one (19B), an efficient biofilm producer and the other (4B), with weak biofilm-forming ability. Mice infected through gastric avages were examined after one and two weeks. Colonization was determined by CFU and urease activity; the anti-H. pylori IgA was measured by ELISA, and chronic infections were evaluated by histopathology. Bacterial communities within mucosal sections were studied by immunofluorescence and scanning electron microscopy (SEM).

RESULTS: Successful infection was obtained by both test strains. Strain 19B with higher ability to form biofilm in vitro also showed a higher colonization rate in the mice stomach one week after infection. Difference (P < 0.05) in IgA titers was observed between the infected mice and the controls as well as between 19B and 4B infected mice, two weeks after the last challenge. Immunofluorescence and SEM results showed tightly colonizing H. pylori in stomach mucosal sections and in squamous and glandular epithelium.

CONCLUSION: H. pylori is able to form biofilm in the mouse stomach and induce IgA production, reflecting the same potential as in humans. Firm attachment of coccoid form bacteria to host cells suggests the importance of this state in biofilm formation by H. pylori. Occurrence of biofilm in squamous and glandular epithelium of the mouse stomach proposes that H. pylori can all parts of the upper gastrointestinal tract.}, } @article {pmid26995104, year = {2016}, author = {Sousa, AS and Prates, RA and de Santi, ME and Lopes, RG and Bussadori, SK and Ferreira, LR and Deana, AM}, title = {Photodynamic inactivation of Candida albicans biofilm: Influence of the radiant energy and photosensitizer charge.}, journal = {Photodiagnosis and photodynamic therapy}, volume = {14}, number = {}, pages = {111-114}, doi = {10.1016/j.pdpdt.2016.03.004}, pmid = {26995104}, issn = {1873-1597}, mesh = {*Biofilms/drug effects/radiation effects ; Candida albicans/*drug effects/*radiation effects ; Methylene Blue/*therapeutic use ; Microscopy, Electron, Scanning ; *Photosensitizing Agents ; Protoporphyrins/*therapeutic use ; }, abstract = {BACKGROUND: The aim of this study is to investigate the photoinactivation of C. albicans biofilm on acrylic resin discs (the standard material for dental prosthesis) using the photosensitizers Methylene Blue and a Protoporphyrin IX.

METHODS: Eighteen thermally activated Methyl Methacrylate Polymers were used for the biofilm growth of Candida albicans ATCC 10231. Two photosensitizers were tested: methylene blue (50μM) and protoporphyrin IX (10μM). Two custom-made LEDs emitting at 660nm and 630nm with approximately 800mW each were used for the irradiation, with duration ranging from 2 to 10min.

RESULTS: This study demonstrates that MB decreased the aPDT CFUs by approximately two orders of magnitude, but the protoporphyrin was ineffective.

CONCLUSION: The aPDT with MB significantly reduces (but does not sterilize) the amount of CFU after 10min of irradiation, and it is not dose-dependent. The lack of effect of the protoporphyrin is likely because the negative charges of the proteoglycans present in the extracellular matrix repel the negative charges of the PS, thus preventing its diffusion in the cells.}, } @article {pmid26994461, year = {2016}, author = {Liu, X and Wang, H and Long, F and Qi, L and Fan, H}, title = {Optimizing and real-time control of biofilm formation, growth and renewal in denitrifying biofilter.}, journal = {Bioresource technology}, volume = {209}, number = {}, pages = {326-332}, doi = {10.1016/j.biortech.2016.02.095}, pmid = {26994461}, issn = {1873-2976}, mesh = {Biofilms/*growth & development ; Biofouling/*prevention & control ; Carbon ; Denitrification ; Filtration/*instrumentation ; Water Purification ; }, abstract = {A pilot-scale denitrifying biofilter (DNBF) with a treatment capacity of 600m(3)/d was used to study real-time control of biofilm formation, removal and renewal. The results showed biofilm formation, growth and removal can be well controlled using on-line monitored turbidity. The status of filter layer condition can be well indicated by Turb break points on turbidity profile. There was a very good linear relationship between biofilm growth degree (Xbiof) and filter clogging degree (Cfilter) with R(2) higher than 0.99. Filter layer clogging coefficient (Yc) lower than 0.27 can be used to determine stable filter layer condition. Since variations of turbidity during backwash well fitted normal distribution with R(2) higher than 0.96, biofilm removal during backwash also can be well optimized by turbidity. Although biofilm structure and nirK-coding denitrifying communities using different carbon sources were much more different, DNBF was still successfully and stably optimized and real-time controlled via on-line turbidity.}, } @article {pmid26993055, year = {2017}, author = {van der Waal, SV and de Almeida, J and Krom, BP and de Soet, JJ and Crielaard, W}, title = {Diffusion of antimicrobials in multispecies biofilms evaluated in a new biofilm model.}, journal = {International endodontic journal}, volume = {50}, number = {4}, pages = {367-376}, doi = {10.1111/iej.12634}, pmid = {26993055}, issn = {1365-2591}, mesh = {Anti-Infective Agents/*metabolism ; *Biofilms/drug effects ; Coloring Agents/metabolism ; Edetic Acid/metabolism ; Humans ; In Vitro Techniques ; Models, Biological ; Saliva/metabolism ; Sodium Chloride/metabolism ; Sodium Hypochlorite/metabolism ; }, abstract = {AIM: To describe the application of a newly-developed in vitro model in which the diffusion of antimicrobials in oral biofilms can be studied.

METHODOLOGY: In a flow chamber consisting of three parallel feeding channels connected with each other by eight perpendicular side channels, multispecies biofilms were grown from saliva of a single donor for 48 h. The dimensions of the side channels were 100 μm × 100 μm × 5130 μm (H × W × L). When one or more side channels were filled with biofilm, the biofilms were stained with fluorescent stains. Then, one side-channel biofilm was selected and treated with phosphate buffered saline, 2% sodium hypochlorite (NaOCl), 17% ethylenediaminetetra-acetic acid (EDTA) or modified salt solution (MSS). Diffusion of the irrigants was observed by acquiring fluorescence images at 10× objective every 15 s for 30 min.

RESULTS: It was possible to culture biofilms in the narrow (100 μm) channels. The biofilms varied in phenotype. In this model, no diffusion of NaOCl into the biofilms was seen after its application. Seventeen-percentage EDTA only diffused into the biofilm up to 200 μm in 30 min. MSS did diffuse in the biofilm over a distance of 450 μm within 2 min after a single application.

CONCLUSIONS: This new model enables the investigation of the diffusion of antimicrobials in biofilms. Other applications to improve our understanding of the characteristics of biofilms are now possible.}, } @article {pmid26992172, year = {2016}, author = {Sanchez, LM and Cheng, AT and Warner, CJ and Townsley, L and Peach, KC and Navarro, G and Shikuma, NJ and Bray, WM and Riener, RM and Yildiz, FH and Linington, RG}, title = {Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0149603}, pmid = {26992172}, issn = {1932-6203}, support = {R21 AI098836/AI/NIAID NIH HHS/United States ; 1R21AI098836-01/AI/NIAID NIH HHS/United States ; 2R25GM05803-12/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biofilms ; Fishes/metabolism ; Gram-Negative Bacteria/*physiology ; }, abstract = {Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection.}, } @article {pmid26992098, year = {2017}, author = {Zaugg, LK and Astasov-Frauenhoffer, M and Braissant, O and Hauser-Gerspach, I and Waltimo, T and Zitzmann, NU}, title = {Determinants of biofilm formation and cleanability of titanium surfaces.}, journal = {Clinical oral implants research}, volume = {28}, number = {4}, pages = {469-475}, doi = {10.1111/clr.12821}, pmid = {26992098}, issn = {1600-0501}, mesh = {Adult ; Aged ; *Alveolar Ridge Augmentation ; *Biofilms ; *Dental Implants ; Dental Restoration Failure ; Female ; Humans ; Male ; Middle Aged ; Postoperative Complications/*diagnosis ; Risk Factors ; Surface Properties ; *Titanium ; Treatment Outcome ; }, abstract = {OBJECTIVE: The aim of the present study was to analyze biofilm formation on four different titanium-based surfaces (machined titanium zirconium (TiZr) alloy, M; machined, acid-etched TiZr alloy, modMA; machined, sandblasted, acid-etched TiZr alloy, modSLA; and micro-grooved titanium aluminum vanadium alloy, TAV MG) in an experimental human model.

MATERIAL AND METHODS: Custom-made discs were mounted in individual intraoral splint housings and worn by 16 volunteers for 24 h. The safranin staining assay, isothermal microcalorimetry (IMC), and SEM were applied before and after surface cleaning.

RESULTS: The hydrophilic surfaces modMA and modSLA with greater surface micro-roughness exhibited significantly more biofilm than the hydrophobic surfaces TAV MG and M. The standardized cleaning procedure substantially reduced the biofilm mass on all surfaces. After cleaning, the IMC analyses demonstrated a longer lag time of the growth curve on TAV MG compared to modSLA. Inter- and intraindividual variations in biofilm formation on the titanium discs were evident throughout the study.

CONCLUSIONS: Surface hydrophilicity and roughness enhanced biofilm formation in vivo, whereas surface topography was the most influential factor that determined surface cleanability. While the grooved surface retained larger amounts of initial biofilm, the machined surface was easier to clean, but proliferation indicated by increased metabolic activity (growth rate) in IMC occurred despite mechanical biofilm removal.}, } @article {pmid26992071, year = {2016}, author = {Larimer, C and Suter, JD and Bonheyo, G and Addleman, RS}, title = {In situ non-destructive measurement of biofilm thickness and topology in an interferometric optical microscope.}, journal = {Journal of biophotonics}, volume = {9}, number = {6}, pages = {656-666}, doi = {10.1002/jbio.201500212}, pmid = {26992071}, issn = {1864-0648}, mesh = {*Biofilms ; *Microscopy, Interference ; Pseudomonas putida/growth & development ; }, abstract = {Biofilms are ubiquitous and impact the environment, human health, dental hygiene, and a wide range of industrial processes. Biofilms are difficult to characterize when fully hydrated, especially in a non-destructive manner, because of their soft structure and water-like bulk properties. Herein a method of measuring and monitoring the thickness and topology of live biofilms of using white light interferometry is described. Using this technique, surface morphology, surface roughness, and biofilm thickness were measured over time without while the biofilm continued to grow. The thickness and surface topology of a P. putida biofilm were monitored growing from initial colonization to a mature biofilm. Measured thickness followed expected trends for bacterial growth. Surface roughness also increased over time and was a leading indicator of biofilm growth.}, } @article {pmid26992034, year = {2016}, author = {Serra, DO and Mika, F and Richter, AM and Hengge, R}, title = {The green tea polyphenol EGCG inhibits E. coli biofilm formation by impairing amyloid curli fibre assembly and downregulating the biofilm regulator CsgD via the σ(E) -dependent sRNA RybB.}, journal = {Molecular microbiology}, volume = {101}, number = {1}, pages = {136-151}, doi = {10.1111/mmi.13379}, pmid = {26992034}, issn = {1365-2958}, mesh = {Amyloid/genetics/*metabolism ; Anti-Infective Agents ; Bacterial Adhesion/physiology ; Bacterial Proteins/antagonists & inhibitors ; Biofilms/*drug effects ; Catechin/*analogs & derivatives/metabolism/pharmacology ; Down-Regulation/drug effects ; Escherichia coli/drug effects/genetics/metabolism/*physiology ; Escherichia coli Proteins/antagonists & inhibitors/genetics/*metabolism ; Promoter Regions, Genetic ; RNA, Messenger/genetics/metabolism ; RNA, Small Untranslated/genetics/metabolism ; Sigma Factor/*metabolism ; Tea/chemistry ; Trans-Activators/antagonists & inhibitors/genetics/*metabolism ; }, abstract = {In bacterial biofilms, which are often involved in chronic infections, cells are surrounded by a self-produced extracellular matrix that contains amyloid fibres, exopolysaccharides and other biopolymers. The matrix contributes to the pronounced resistance of biofilms against antibiotics and host immune systems. Being highly inflammatory, matrix amyloids such as curli fibres of Escherichia coli can also play a role in pathogenicity. Using macrocolony biofilms of commensal and pathogenic E. coli as a model system, we demonstrate here that the green tea polyphenol epigallocatachin gallate (EGCG) is a potent antibiofilm agent. EGCG virtually eliminates the biofilm matrix by directly interfering with the assembly of curli subunits into amyloid fibres, and by triggering the σ(E) cell envelope stress response and thereby reducing the expression of CsgD - a crucial activator of curli and cellulose biosynthesis - due to csgD mRNA targeting by the σ(E) -dependent sRNA RybB. These findings highlight EGCG as a potential adjuvant for antibiotic therapy of biofilm-associated infections. Moreover, EGCG may support therapies against pathogenic E. coli that produce inflammatory curli fibres along with Shigatoxin.}, } @article {pmid26991283, year = {2016}, author = {Charnock, C and Nordlie, AL}, title = {Proteobacteria, extremophiles and unassigned species dominate in a tape-like showerhead biofilm.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {47}, number = {2}, pages = {345-351}, pmid = {26991283}, issn = {1678-4405}, mesh = {*Biofilms ; DNA, Bacterial/genetics ; Proteobacteria/chemistry/genetics/*isolation & purification/*physiology ; RNA, Ribosomal, 16S/genetics ; Staining and Labeling ; }, abstract = {The development of showerhead biofilms exposes the user to repeated contact with potentially pathogenic microbes, yet we know relatively little about the content of these aggregates. The aim of the present study was to examine the microbial content of tape-like films found protruding from a domestic showerhead. Culturing showed that the films were dominated by aerobic α- and β-proteobacteria. Three isolates made up almost the entire plate count. These were a Brevundimonas species, a metalophilic Cupriavidus species and a thermophile, Geobacillus species. Furthermore, it was shown that the Cupriavidus isolate alone had a high capacity for biofilm formation and thus might be the initiator of biofilm production. A clone library revealed the same general composition. However, half of the 70 clones analyzed could not be assigned to a particular bacterial phylum and of these 29 differed from one another by only 1-2 base pairs, indicating a single species. Thus both the culture dependent and culture independent characterizations suggest a simple yet novel composition. The work is important as the biofilm is fundamentally different in form (tape-like) and content from that of all previously reported ones, where variously Mycobacterium, Methylobacterium and Xanthomonas species have dominated, and extremophiles were not reported.}, } @article {pmid26989738, year = {2015}, author = {Taghadosi, R and Shakibaie, MR and Masoumi, S}, title = {Biochemical detection of N-Acyl homoserine lactone from biofilm-forming uropathogenic Escherichia coli isolated from urinary tract infection samples.}, journal = {Reports of biochemistry & molecular biology}, volume = {3}, number = {2}, pages = {56-61}, pmid = {26989738}, issn = {2322-3480}, abstract = {BACKGROUND: N-Acyl homoserine lactone (AHL) is found to be the main component of quorum sensing (QS) in Gram-negative bacteria and plays an important role in biofilm formation. Little information is available regarding the role of AHL in biofilm formation in Escherichia coli (E. coli). The purpose of this investigation was to biochemically detect and characterize AHL activity in biofilm-forming uropathogenic E. coli (UPEC) isolated from urine samples of the patients with urinary tract infections (UTIs) in Kerman, Iran.

METHODS: Thirty-five UPEC isolates were obtained from urine samples of the patients with UTIs referred to the Afzalipoor hospital. The isolates were identified by biochemical tests. Biofilm analyses of all the isolates were performed using the microtiter plate method at OD 490nm. N-Acyl homoserine lactone was separated from cell mass supernatants by liquid-liquid extraction (LLE) and analyzed by a colorimetric method. N-Acyl homoserine lactone functional groups were identified by Fourier Transform-Infrared Spectroscopy (FT-IR).

RESULTS: The biofilm formation assay identified 10 (28.57%) isolates with strong, 16 (45.71%) with moderate, and 9 (25.71%) with weak biofilm activities. The UPEC isolates with strong and weak biofilm activities were subjected to AHL analyses. It was found that isolates with the highest AHL activities also exhibited strong adherence to microplate wells (P≤0.05). Two E. coli isolates with the highest AHL activities were selected for FT-IR spectroscopy. Peaks at 1764.33, 1377.99, and 1242.90 cm(-1) correspond to the C=O bond of the lactone ring, and the N=H and C-O bonds of the acyl chain, respectively.

CONCLUSION: We found that many UPEC isolates exhibited strong biofilm formation. The control of this property by AHL may contribute to the pathogenesis of the organism in UTI's.}, } @article {pmid26988714, year = {2017}, author = {Rocco, CJ and Davey, ME and Bakaletz, LO and Goodman, SD}, title = {Natural antigenic differences in the functionally equivalent extracellular DNABII proteins of bacterial biofilms provide a means for targeted biofilm therapeutics.}, journal = {Molecular oral microbiology}, volume = {32}, number = {2}, pages = {118-130}, pmid = {26988714}, issn = {2041-1014}, support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 DE019117/DE/NIDCR NIH HHS/United States ; }, mesh = {Antibodies, Bacterial/immunology ; Antigens, Bacterial/*immunology ; Bacterial Adhesion/*immunology ; Bacterial Proteins/*immunology ; *Biofilms ; DNA, Bacterial/metabolism ; DNA-Binding Proteins/*immunology ; DnaB Helicases/*immunology ; Microscopy, Fluorescence ; Porphyromonas gingivalis/drug effects/immunology/*physiology ; Streptococcus gordonii/drug effects/immunology/*physiology ; }, abstract = {Bacteria that persist in the oral cavity exist within complex biofilm communities. A hallmark of biofilms is the presence of an extracellular polymeric substance (EPS), which consists of polysaccharides, extracellular DNA (eDNA), and proteins, including the DNABII family of proteins. The removal of DNABII proteins from a biofilm results in the loss of structural integrity of the eDNA and the collapse of the biofilm structure. We examined the role of DNABII proteins in the biofilm structure of the periodontal pathogen Porphyromonas gingivalis and the oral commensal Streptococcus gordonii. Co-aggregation with oral streptococci is thought to facilitate the establishment of P. gingivalis within the biofilm community. We demonstrate that DNABII proteins are present in the EPS of both S. gordonii and P. gingivalis biofilms, and that these biofilms can be disrupted through the addition of antisera derived against their respective DNABII proteins. We provide evidence that both eDNA and DNABII proteins are limiting in S. gordonii but not in P. gingivalis biofilms. In addition, these proteins are capable of complementing one another functionally. We also found that whereas antisera derived against most DNABII proteins are capable of binding a wide variety of DNABII proteins, the P. gingivalis DNABII proteins are antigenically distinct. The presence of DNABII proteins in the EPS of these biofilms and the antigenic uniqueness of the P. gingivalis proteins provide an opportunity to develop therapies that are targeted to remove P. gingivalis and biofilms that contain P. gingivalis from the oral cavity.}, } @article {pmid26987892, year = {2016}, author = {Benoit, DS and Koo, H}, title = {Targeted, triggered drug delivery to tumor and biofilm microenvironments.}, journal = {Nanomedicine (London, England)}, volume = {11}, number = {8}, pages = {873-879}, doi = {10.2217/nnm-2016-0014}, pmid = {26987892}, issn = {1748-6963}, support = {K12 ES019852/ES/NIEHS NIH HHS/United States ; R01 DE018023/DE/NIDCR NIH HHS/United States ; DE018023/DE/NIDCR NIH HHS/United States ; K12ES019852/ES/NIEHS NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*administration & dosage ; Antineoplastic Agents/*administration & dosage ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy/microbiology ; Biofilms/*drug effects ; Delayed-Action Preparations/chemistry ; Drug Carriers/chemistry ; Drug Delivery Systems/*methods ; Humans ; Hydrogen-Ion Concentration ; Nanoparticles/chemistry ; Neoplasms/*drug therapy ; Tumor Microenvironment/*drug effects ; }, } @article {pmid26987441, year = {2016}, author = {Wood, TL and Wood, TK}, title = {The HigB/HigA toxin/antitoxin system of Pseudomonas aeruginosa influences the virulence factors pyochelin, pyocyanin, and biofilm formation.}, journal = {MicrobiologyOpen}, volume = {5}, number = {3}, pages = {499-511}, pmid = {26987441}, issn = {2045-8827}, mesh = {Amino Acid Sequence ; Bacterial Proteins/genetics/*metabolism ; Bacterial Toxins/genetics/*metabolism ; Biofilms/*growth & development ; Cloning, Molecular ; Escherichia coli/growth & development/metabolism ; Oligopeptides/*metabolism ; Phenols/*metabolism ; Pseudomonas aeruginosa/genetics/metabolism/*pathogenicity ; Pyocyanine/genetics/*metabolism ; Thiazoles/*metabolism ; Virulence Factors/genetics/*metabolism ; }, abstract = {Toxin/antitoxin (TA) systems are prevalent in most bacterial and archaeal genomes, and one of the emerging physiological roles of TA systems is to help regulate pathogenicity. Although TA systems have been studied in several model organisms, few studies have investigated the role of TA systems in pseudomonads. Here, we demonstrate that the previously uncharacterized proteins HigB (unannotated) and HigA (PA4674) of Pseudomonas aeruginosa PA14 form a type II TA system in which antitoxin HigA masks the RNase activity of toxin HigB through direct binding. Furthermore, toxin HigB reduces production of the virulence factors pyochelin, pyocyanin, swarming, and biofilm formation; hence, this system affects the pathogencity of this strain in a manner that has not been demonstrated previously for TA systems.}, } @article {pmid26986772, year = {2016}, author = {Beaudoin, T and Waters, V}, title = {Infections With Biofilm Formation: Selection of Antimicrobials and Role of Prolonged Antibiotic Therapy.}, journal = {The Pediatric infectious disease journal}, volume = {35}, number = {6}, pages = {695-697}, doi = {10.1097/INF.0000000000001144}, pmid = {26986772}, issn = {1532-0987}, mesh = {Anti-Bacterial Agents/*administration & dosage ; Bacterial Infections/*drug therapy ; Biofilms/*growth & development ; Catheter-Related Infections/*drug therapy ; Cystic Fibrosis/*complications ; Humans ; }, } @article {pmid26986529, year = {2015}, author = {Windler, M and Leinweber, K and Bartulos, CR and Philipp, B and Kroth, PG}, title = {Biofilm and capsule formation of the diatom Achnanthidium minutissimum are affected by a bacterium.}, journal = {Journal of phycology}, volume = {51}, number = {2}, pages = {343-355}, doi = {10.1111/jpy.12280}, pmid = {26986529}, issn = {1529-8817}, abstract = {Photoautotrophic biofilms play an important role in various aquatic habitats and are composed of prokaryotic and/or eukaryotic organisms embedded in extracellular polymeric substances (EPS). We have isolated diatoms as well as bacteria from freshwater biofilms to study organismal interactions between representative isolates. We found that bacteria have a strong impact on the biofilm formation of the pennate diatom Achnanthidium minutissimum. This alga produces extracellular capsules of insoluble EPS, mostly carbohydrates (CHO), only in the presence of bacteria (xenic culture). The EPS themselves also have a strong impact on the aggregation and attachment of the algae. In the absence of bacteria (axenic culture), A. minutissimum did not form capsules and the cells grew completely suspended. Fractionation and quantification of CHO revealed that the diatom in axenic culture produces large amounts of soluble CHO, whereas in the xenic culture mainly insoluble CHO were detected. For investigation of biofilm formation by A. minutissimum, a bioassay was established using a diatom satellite Bacteroidetes bacterium that had been shown to induce capsule formation of A. minutissimum. Interestingly, capsule and biofilm induction can be achieved by addition of bacterial spent medium, indicating that soluble hydrophobic molecules produced by the bacterium may mediate the diatom/bacteria interaction. With the designed bioassay, a reliable tool is now available to study the chemical interactions between diatoms and bacteria with consequences for biofilm formation.}, } @article {pmid26986496, year = {2016}, author = {Gonzalez-Silva, BM and Jonassen, KR and Bakke, I and Østgaard, K and Vadstein, O}, title = {Nitrification at different salinities: Biofilm community composition and physiological plasticity.}, journal = {Water research}, volume = {95}, number = {}, pages = {48-58}, doi = {10.1016/j.watres.2016.02.050}, pmid = {26986496}, issn = {1879-2448}, mesh = {Ammonia ; Bacteria/genetics ; *Biofilms ; Bioreactors/microbiology ; *Nitrification ; Oxidation-Reduction ; RNA, Ribosomal, 16S/genetics ; }, abstract = {This paper describes an experimental study of microbial communities of three moving bed biofilm reactors (MBBR) inoculated with nitrifying cultures originated from environments with different salinity; freshwater, brackish (20‰) and seawater. All reactors were run until they operated at a conversion efficiency of >96%. The microbial communities were profiled using 454-pyrosequencing of 16S rRNA gene amplicons. Statistical analysis was used to investigate the differences in microbial community structure and distribution of the nitrifying populations with different salinity environments. Nonmetric multidimensional scaling analysis (NMDS) and the PERMANOVA test based on Bray-Curtis similarities revealed significantly different community structure in the three reactors. The brackish reactor showed lower diversity index than fresh and seawater reactors. Venn diagram showed that 60 and 78% of the total operational taxonomic units (OTUs) in the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) guild, respectively, were unique OTUs for a given reactor. Similarity Percentages (SIMPER) analysis showed that two-thirds of the total difference in community structure between the reactors was explained by 10 OTUs, indicating that only a small number of OTUs play a numerically dominant role in the nitrification process. Acute toxicity of salt stress on ammonium and nitrite oxidizing activities showed distinctly different patterns, reaching 97% inhibition of the freshwater reactor for ammonium oxidation rate. In the brackish culture, inhibition was only observed at maximal level of salinity, 32‰. In the fully adapted seawater culture, higher activities were observed at 32‰ than at any of the lower salinities.}, } @article {pmid26986463, year = {2016}, author = {Nizalapur, S and Ho, KK and Kimyon, Ö and Yee, E and Berry, T and Manefield, M and Cranfield, CG and Willcox, M and Black, DS and Kumar, N}, title = {Synthesis and biological evaluation of N-naphthoyl-phenylglyoxamide-based small molecular antimicrobial peptide mimics as novel antimicrobial agents and biofilm inhibitors.}, journal = {Organic & biomolecular chemistry}, volume = {14}, number = {14}, pages = {3623-3637}, doi = {10.1039/c6ob00298f}, pmid = {26986463}, issn = {1477-0539}, mesh = {Anti-Bacterial Agents/*chemistry/pharmacology ; Biofilms/*drug effects ; Microbial Sensitivity Tests ; *Molecular Mimicry ; Peptides/*pharmacology ; Sulfonylurea Compounds/*chemistry/pharmacology ; }, abstract = {Antimicrobial peptides (AMPs) are a key component of the human immune system. Synthetic AMP mimics represent a novel strategy to counteract the increasing incidence of antimicrobial resistance. Here, we describe the synthesis of novel glyoxamide derivatives via ring-opening reactions of N-hexanoyl, N-benzoyl and N-naphthoylisatins with N,N-dimethylethane-1,2-diamine and N,N-dimethylpropane-1,3-diamine. These were converted to both the hydrochloric acid (HCl) or quaternary ammonium iodide (MeI) salts and their antibacterial activity against Staphylococcus aureus was investigated by their zone-of-inhibition and minimum inhibitory concentration (MIC). The HCl salt 22b exhibited the lowest MIC of 16 μg mL(-1), whereas the corresponding MeI salt 22c had a MIC of 39 μg mL(-1). We also investigated the in vitro toxicity of active compounds against the MRC-5 normal human lung fibroblasts and their activity against established biofilm in S. aureus.}, } @article {pmid26984479, year = {2016}, author = {Ali, N and Yousaf, S and Anam, M and Bangash, Z and Maleeha, S}, title = {Evaluating the efficiency of a mixed culture biofilm for the treatment of black liquor and molasses in a mediator-less microbial fuel cell.}, journal = {Environmental technology}, volume = {37}, number = {22}, pages = {2815-2822}, doi = {10.1080/09593330.2016.1166267}, pmid = {26984479}, issn = {1479-487X}, mesh = {*Bioelectric Energy Sources ; Biofilms ; Biological Oxygen Demand Analysis ; Electricity ; Industrial Waste ; *Molasses ; Sewage ; Waste Disposal, Fluid/*methods ; }, abstract = {A microbial fuel cell (MFC) is an emerging environment-friendly technology to recover the useful energy available in waste by using microorganisms as catalyst. In this study, double chamber mediator-less MFCs separated by proton exchange membrane (PEM; Nafion) were constructed to determine the efficiency of mixed culture in using complex substrates (molasses and black liquor). It was found that activated sludge can serve as efficient source of electricigens for biofilm development on an anode. Power density of 2.425 W/m[2] was generated from molasses with chemical oxygen demand (COD) removal efficiency of 67% as compared to power density of 3.55 W/m[2] produced from black liquor along with COD removal efficiency of 78%. Moreover, it was demonstrated that surface area of PEM has a significant effect on power generation. An almost 5- to 8-fold increase in voltage was observed as the size of PEM was increased from 6.5 to 25 cm[2].}, } @article {pmid26984293, year = {2016}, author = {Liu, L and Fang, H and Yang, H and Zhang, Y and Han, Y and Zhou, D and Yang, R}, title = {Reciprocal regulation of Yersinia pestis biofilm formation and virulence by RovM and RovA.}, journal = {Open biology}, volume = {6}, number = {3}, pages = {}, pmid = {26984293}, issn = {2046-2441}, mesh = {Animals ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Female ; *Gene Expression Regulation, Bacterial ; Genes, Regulator ; Mice ; Mice, Inbred BALB C ; Plague/metabolism/*microbiology/pathology ; Virulence Factors/*genetics/metabolism ; Yersinia pestis/genetics/pathogenicity/*physiology ; }, abstract = {RovA is known to enhance Yersinia pestis virulence by directly upregulating the psa loci. This work presents a complex gene regulatory paradigm involving the reciprocal regulatory action of RovM and RovA on the expression of biofilm and virulence genes as well as on their own genes. RovM and RovA enhance and inhibit Y. pestis biofilm production, respectively, whereas RovM represses virulence in mice. RovM directly stimulates the transcription of hmsT, hmsCDE and rovM, while indirectly enhancing hmsHFRS transcription. It also indirectly represses hmsP transcription. By contrast, RovA directly represses hmsT transcription and indirectly inhibits waaAE-coaD transcription, while RovM inhibits psaABC and psaEF transcription by directly repressing rovA transcription. rovM expression is significantly upregulated at 26°C (the temperature of the flea gut) relative to 37°C (the warm-blooded host temperature). We speculate that upregulation of rovM together with downregulation of rovA in the flea gut would promote Y. pestis biofilm formation while inhibiting virulence gene expression, leading to a more transmissible infection of this pathogen in fleas. Once the bacterium shifts to a lifestyle in the warm-blooded hosts, inhibited RovM production accompanied by recovered RovA synthesis would encourage virulence factor production and inhibit biofilm gene expression.}, } @article {pmid26984142, year = {2016}, author = {Paganelli, FL and Huebner, J and Singh, KV and Zhang, X and van Schaik, W and Wobser, D and Braat, JC and Murray, BE and Bonten, MJ and Willems, RJ and Leavis, HL}, title = {Genome-wide Screening Identifies Phosphotransferase System Permease BepA to Be Involved in Enterococcus faecium Endocarditis and Biofilm Formation.}, journal = {The Journal of infectious diseases}, volume = {214}, number = {2}, pages = {189-195}, doi = {10.1093/infdis/jiw108}, pmid = {26984142}, issn = {1537-6613}, mesh = {Animals ; Biofilms/*growth & development ; DNA Transposable Elements ; Disease Models, Animal ; Endocarditis, Bacterial/*microbiology/*physiopathology ; Enterococcus faecium/*enzymology/pathogenicity/*physiology ; Female ; Gene Knockout Techniques ; Genetic Testing ; Membrane Transport Proteins/genetics/*metabolism ; Mutagenesis, Insertional ; Phosphotransferases/genetics/metabolism ; Rats, Wistar ; Virulence Factors/genetics/*metabolism ; }, abstract = {Enterococcus faecium is a common cause of nosocomial infections, of which infective endocarditis is associated with substantial mortality. In this study, we used a microarray-based transposon mapping (M-TraM) approach to evaluate a rat endocarditis model and identified a gene, originally annotated as "fruA" and renamed "bepA," putatively encoding a carbohydrate phosphotransferase system (PTS) permease (biofilm and endocarditis-associated permease A [BepA]), as important in infective endocarditis. This gene is highly enriched in E. faecium clinical isolates and absent in commensal isolates that are not associated with infection. Confirmation of the phenotype was established in a competition experiment of wild-type and a markerless bepA mutant in a rat endocarditis model. In addition, deletion of bepA impaired biofilm formation in vitro in the presence of 100% human serum and metabolism of β-methyl-D-glucoside. β-glucoside metabolism has been linked to the metabolism of glycosaminoglycans that are exposed on injured heart valves, where bacteria attach and form vegetations. Therefore, we propose that the PTS permease BepA is directly implicated in E. faecium pathogenesis.}, } @article {pmid26983427, year = {2016}, author = {Duwelius, PJ}, title = {CORR Insights(®): Antibiotic-tolerant Staphylococcus aureus Biofilm Persists on Arthroplasty Materials.}, journal = {Clinical orthopaedics and related research}, volume = {474}, number = {7}, pages = {1657-1658}, pmid = {26983427}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents ; Arthroplasty ; *Biofilms ; Humans ; Staphylococcal Infections ; *Staphylococcus aureus ; }, } @article {pmid26981759, year = {2016}, author = {Rezende, GC and Massunari, L and Queiroz, IO and Gomes Filho, JE and Jacinto, RC and Lodi, CS and Dezan Junior, E}, title = {Antimicrobial action of calcium hydroxide-based endodontic sealers after setting, against E. faecalis biofilm.}, journal = {Brazilian oral research}, volume = {30}, number = {}, pages = {}, doi = {10.1590/1807-3107BOR-2016.vol30.0038}, pmid = {26981759}, issn = {1807-3107}, mesh = {Analysis of Variance ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Calcium Hydroxide/chemistry/*pharmacology ; Cattle ; Colony Count, Microbial ; Enterococcus faecalis/*drug effects ; Epoxy Resins/chemistry/*pharmacology ; Materials Testing ; Microbial Sensitivity Tests ; Reproducibility of Results ; Root Canal Filling Materials/chemistry/*pharmacology ; Salicylates/chemistry/*pharmacology ; Statistics, Nonparametric ; Time Factors ; }, abstract = {Enterococcus faecalis are gram positive bacteria that can mostly resist endodontic therapy, inducing persistent infection in the root canal system. Endodontic sealers with antimicrobial activity may help eliminate residual microorganisms that survive endodontic treatment. The present study aimed at comparing the antimicrobial activity of Acroseal, Sealapex and AH Plus endodontic sealers in an in vitro biofilm model. Bovine dentin specimens (144) were prepared, and twelve blocks for each sealer and each experimental time point (2, 7 and 14 days) were placed and left in contact with plates containing inoculum of E. faecalis (ATCC 51299), to induce biofilm formation. After 14 days, the samples were transferred to another plate with test sealers and kept at 37°C and 5% CO2 for 2, 7 and 14 days. The specimens without sealers were used as a control for each period. The samples were agitated in a sonicator after each experiment. The suspensions were agitated in a vortex mixer, serially diluted in saline, and triple plated onto m-Enterococcus agar. Colonyforming units were counted, and the data were statistically analyzed using ANOVA, Shapiro-Wilk and Kruskal-Wallis one-way tests (p < 0.05) to determine antimicrobial potential. Sealapex showed significant differences at all the experimental time points, in comparison with all the other groups. AH Plus and Acroseal showed antimicrobial activity only on the 14th experimental day. Neither of the sealers tested were able to completely eliminate the biofilm. Sealapex showed the highest antimicrobial activity in all the experimental periods. The antimicrobial activity of all the sealers analyzed increased over time.}, } @article {pmid26981756, year = {2016}, author = {Verardi, G and Cenci, MS and Maske, TT and Webber, B and Santos, LR}, title = {Antiseptics and microcosm biofilm formation on titanium surfaces.}, journal = {Brazilian oral research}, volume = {30}, number = {}, pages = {}, doi = {10.1590/1807-3107BOR-2016.vol30.0030}, pmid = {26981756}, issn = {1807-3107}, mesh = {Analysis of Variance ; Anti-Infective Agents, Local/chemistry/*pharmacology ; Bacterial Adhesion/*drug effects ; Bacterial Load ; Biofilms/*drug effects/growth & development ; Chloramines/chemistry/pharmacology ; Chlorhexidine/chemistry/pharmacology ; Humans ; Mouthwashes/chemistry/*pharmacology ; Oils, Volatile/chemistry/pharmacology ; Reproducibility of Results ; Saliva/microbiology ; Surface Properties/drug effects ; Time Factors ; Titanium/*chemistry ; Tosyl Compounds/chemistry/pharmacology ; Triclosan/chemistry/pharmacology ; }, abstract = {Oral rehabilitation with osseointegrated implants is a way to restore esthetics and masticatory function in edentulous patients, but bacterial colonization around the implants may lead to mucositis or peri-implantitis and consequent implant loss. Peri-implantitis is the main complication of oral rehabilitation with dental implants and, therefore, it is necessary to take into account the potential effects of antiseptics such as chlorhexidine (CHX), chloramine T (CHT), triclosan (TRI), and essential oils (EO) on bacterial adhesion and on biofilm formation. To assess the action of these substances, we used the microcosm technique, in which the oral environment and periodontal conditions are simulated in vitro on titanium discs with different surface treatments (smooth surface - SS, acid-etched smooth surface - AESS, sand-blasted surface - SBS, and sand-blasted and acid-etched surface - SBAES). Roughness measurements yielded the following results: SS: 0.47 µm, AESS: 0.43 µm, SB: 0.79 µm, and SBAES: 0.72 µm. There was statistical difference only between SBS and AESS. There was no statistical difference among antiseptic treatments. However, EO and CHT showed lower bacterial counts compared with the saline solution treatment (control group). Thus, the current gold standard (CHX) did not outperform CHT and EO, which were efficient in reducing the biofilm biomass compared with saline solution.}, } @article {pmid26980595, year = {2016}, author = {Ammann, CG and Nagl, M and Nogler, M and Coraça-Huber, DC}, title = {Pseudomonas aeruginosa outcompetes other bacteria in the manifestation and maintenance of a biofilm in polyvinylchloride tubing as used in dental devices.}, journal = {Archives of microbiology}, volume = {198}, number = {4}, pages = {389-391}, pmid = {26980595}, issn = {1432-072X}, mesh = {Antibiosis ; Bacterial Load ; *Bacterial Physiological Phenomena ; *Biofilms ; *Dental Materials ; Klebsiella pneumoniae/physiology ; Microbial Sensitivity Tests ; *Polyvinyl Chloride ; Pseudomonas aeruginosa/*physiology ; Pyocyanine/metabolism ; Staphylococcus aureus/physiology ; }, abstract = {In a PVC tube as a model system for dental devices, Pseudomonas aeruginosa outcompetes Staphylococcus aureus and Klebsiella pneumoniae for the biofilm formation. P. aeruginosa has advantage over the other strains due to higher tolerance for low-nutrient situations or direct killing by the production of soluble factors like pyocyanin.}, } @article {pmid26980068, year = {2016}, author = {Mizan, MF and Jahid, IK and Kim, M and Lee, KH and Kim, TJ and Ha, SD}, title = {Variability in biofilm formation correlates with hydrophobicity and quorum sensing among Vibrio parahaemolyticus isolates from food contact surfaces and the distribution of the genes involved in biofilm formation.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {497-509}, doi = {10.1080/08927014.2016.1149571}, pmid = {26980068}, issn = {1029-2454}, mesh = {Biofilms/*growth & development ; Fimbriae, Bacterial ; Food Contamination/prevention & control ; Foodborne Diseases/microbiology/prevention & control ; Humans ; *Hydrophobic and Hydrophilic Interactions ; *Quorum Sensing ; Seafood/microbiology ; *Vibrio parahaemolyticus/pathogenicity/physiology ; }, abstract = {Vibrio parahaemolyticus is one of the leading foodborne pathogens causing seafood contamination. Here, 22 V. parahaemolyticus strains were analyzed for biofilm formation to determine whether there is a correlation between biofilm formation and quorum sensing (QS), swimming motility, or hydrophobicity. The results indicate that the biofilm formation ability of V. parahaemolyticus is positively correlated with cell surface hydrophobicity, autoinducer (AI-2) production, and protease activity. Field emission scanning electron microscopy (FESEM) showed that strong-biofilm-forming strains established thick 3-D structures, whereas poor-biofilm-forming strains produced thin inconsistent biofilms. In addition, the distribution of the genes encoding pandemic clone factors, type VI secretion systems (T6SS), biofilm functions, and the type I pilus in the V. parahaemolyticus seafood isolates were examined. Biofilm-associated genes were present in almost all the strains, irrespective of other phenotypes. These results indicate that biofilm formation on/in seafood may constitute a major factor in the dissemination of V. parahaemolyticus and the ensuing diseases.}, } @article {pmid26979871, year = {2016}, author = {Guilhen, C and Charbonnel, N and Parisot, N and Gueguen, N and Iltis, A and Forestier, C and Balestrino, D}, title = {Transcriptional profiling of Klebsiella pneumoniae defines signatures for planktonic, sessile and biofilm-dispersed cells.}, journal = {BMC genomics}, volume = {17}, number = {}, pages = {237}, pmid = {26979871}, issn = {1471-2164}, mesh = {Bacterial Adhesion/*genetics ; *Biofilms ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial ; Klebsiella pneumoniae/*genetics/physiology ; RNA, Bacterial/genetics ; Sequence Analysis, RNA ; *Transcriptome ; }, abstract = {BACKGROUND: Surface-associated communities of bacteria, known as biofilms, play a critical role in the persistence and dissemination of bacteria in various environments. Biofilm development is a sequential dynamic process from an initial bacterial adhesion to a three-dimensional structure formation, and a subsequent bacterial dispersion. Transitions between these different modes of growth are governed by complex and partially known molecular pathways.

RESULTS: Using RNA-seq technology, our work provided an exhaustive overview of the transcriptomic behavior of the opportunistic pathogen Klebsiella pneumoniae derived from free-living, biofilm and biofilm-dispersed states. For each of these conditions, the combined use of Z-scores and principal component analysis provided a clear illustration of distinct expression profiles. In particular, biofilm-dispersed cells appeared as a unique stage in the bacteria lifecycle, different from both planktonic and sessile states. The K-means cluster analysis showed clusters of Coding DNA Sequences (CDS) and non-coding RNA (ncRNA) genes differentially transcribed between conditions. Most of them included dominant functional classes, emphasizing the transcriptional changes occurring in the course of K. pneumoniae lifestyle transitions. Furthermore, analysis of the whole transcriptome allowed the selection of an overall of 40 transcriptional signature genes for the five bacterial physiological states.

CONCLUSIONS: This transcriptional study provides additional clues to understand the key molecular mechanisms involved in the transition between biofilm and the free-living lifestyles, which represents an important challenge to control both beneficial and harmful biofilm. Moreover, this exhaustive study identified physiological state specific transcriptomic reference dataset useful for the research community.}, } @article {pmid26979645, year = {2017}, author = {Schlafer, S and Meyer, RL}, title = {Confocal microscopy imaging of the biofilm matrix.}, journal = {Journal of microbiological methods}, volume = {138}, number = {}, pages = {50-59}, doi = {10.1016/j.mimet.2016.03.002}, pmid = {26979645}, issn = {1872-8359}, mesh = {*Biofilms ; *Extracellular Matrix ; Fluorescence Recovery After Photobleaching/methods ; Fluorescence Resonance Energy Transfer/methods ; Fluorescent Dyes ; Microscopy, Confocal/*methods ; Staining and Labeling/methods ; }, abstract = {The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens. Confocal microscopes are held by many research groups, and a number of methods for qualitative and quantitative imaging of the matrix have emerged in recent years. This review provides an overview and a critical discussion of techniques used to visualize different matrix compounds, to determine the concentration of solutes and the diffusive properties of the biofilm matrix.}, } @article {pmid26978068, year = {2016}, author = {Harris, LG and Murray, S and Pascoe, B and Bray, J and Meric, G and Mageiros, L and Wilkinson, TS and Jeeves, R and Rohde, H and Schwarz, S and de Lencastre, H and Miragaia, M and Rolo, J and Bowden, R and Jolley, KA and Maiden, MC and Mack, D and Sheppard, SK}, title = {Biofilm Morphotypes and Population Structure among Staphylococcus epidermidis from Commensal and Clinical Samples.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0151240}, pmid = {26978068}, issn = {1932-6203}, support = {090532/Z/09/Z//Wellcome Trust/United Kingdom ; 087622//Wellcome Trust/United Kingdom ; G0801929//Medical Research Council/United Kingdom ; MR/M501608/1//Medical Research Council/United Kingdom ; MR/L015080/1//Medical Research Council/United Kingdom ; //Wellcome Trust/United Kingdom ; 088786/C/09/Z//Wellcome Trust/United Kingdom ; }, mesh = {Biofilms/classification/*growth & development ; Cross Infection/*microbiology ; Humans ; Phylogeny ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/*genetics ; }, abstract = {Bacterial species comprise related genotypes that can display divergent phenotypes with important clinical implications. Staphylococcus epidermidis is a common cause of nosocomial infections and, critical to its pathogenesis, is its ability to adhere and form biofilms on surfaces, thereby moderating the effect of the host's immune response and antibiotics. Commensal S. epidermidis populations are thought to differ from those associated with disease in factors involved in adhesion and biofilm accumulation. We quantified the differences in biofilm formation in 98 S. epidermidis isolates from various sources, and investigated population structure based on ribosomal multilocus typing (rMLST) and the presence/absence of genes involved in adhesion and biofilm formation. All isolates were able to adhere and form biofilms in in vitro growth assays and confocal microscopy allowed classification into 5 biofilm morphotypes based on their thickness, biovolume and roughness. Phylogenetic reconstruction grouped isolates into three separate clades, with the isolates in the main disease associated clade displaying diversity in morphotype. Of the biofilm morphology characteristics, only biofilm thickness had a significant association with clade distribution. The distribution of some known adhesion-associated genes (aap and sesE) among isolates showed a significant association with the species clonal frame. These data challenge the assumption that biofilm-associated genes, such as those on the ica operon, are genetic markers for less invasive S. epidermidis isolates, and suggest that phenotypic characteristics, such as adhesion and biofilm formation, are not fixed by clonal descent but are influenced by the presence of various genes that are mobile among lineages.}, } @article {pmid26978023, year = {2016}, author = {Vinod Kumar, K and Lall, C and Raj, RV and Vedhagiri, K and Sunish, IP and Vijayachari, P}, title = {In Vitro Antimicrobial Susceptibility of Pathogenic Leptospira Biofilm.}, journal = {Microbial drug resistance (Larchmont, N.Y.)}, volume = {22}, number = {7}, pages = {511-514}, doi = {10.1089/mdr.2015.0284}, pmid = {26978023}, issn = {1931-8448}, mesh = {Ampicillin/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Doxycycline/pharmacology ; Drug Resistance, Multiple, Bacterial/*physiology ; Leptospira/*drug effects/physiology ; Microbial Sensitivity Tests ; Penicillin G/pharmacology ; Plankton/*drug effects/growth & development ; Tetracycline/pharmacology ; }, abstract = {Pathogenic Leptospira spp. are the causative agent of leptospirosis. Biofilm formation in leptospires is a new area of study, and its role in pathogenesis is not fully explored. As in other biofilm-forming bacteria, Leptospira biofilm may play a significant role in antibiotic resistance. In this study, the antimicrobial susceptibility of Leptospira biofilm was investigated by 96-well plate assay using Alamar Blue. Leptospira biofilm showed five to sixfold increase in resistance in all the strains used. The range of minimal bactericidal concentrations for penicillin G, ampicillin, tetracycline, and doxycycline was 1,600 U/ml, 800-1,600 μg/ml, 800-1,600 μg/ml, and 800-1,600 μg/ml, respectively. In agar substrate, the biofilm showed six- to sevenfold increase in resistance to antibiotics compared to planktonic cell. The present study emphasizes the importance of biofilm formation and its antibiotic susceptibility patterns. This could pave the way for devising appropriate strategy to prevent the occurrence of potential chronic leptospirosis in endemic areas and also during an outbreak situation.}, } @article {pmid26977344, year = {2016}, author = {Zhong, N and Zhao, M and Li, Y}, title = {U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring.}, journal = {Biomedical optics express}, volume = {7}, number = {2}, pages = {335-351}, pmid = {26977344}, issn = {2156-7085}, abstract = {To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes' Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide-silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0-536 μm.}, } @article {pmid26977108, year = {2016}, author = {Brooks, JF and Mandel, MJ}, title = {The Histidine Kinase BinK Is a Negative Regulator of Biofilm Formation and Squid Colonization.}, journal = {Journal of bacteriology}, volume = {198}, number = {19}, pages = {2596-2607}, pmid = {26977108}, issn = {1098-5530}, support = {R25 GM079300/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; IOS-1456963//National Science Foundation/International ; }, mesh = {Aliivibrio fischeri/*enzymology/metabolism/*physiology ; Animals ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; Gene Expression Regulation, Enzymologic ; Histidine Kinase/genetics/*metabolism ; }, abstract = {UNLABELLED: Bacterial colonization of animal epithelial tissue is a dynamic process that relies on precise molecular communication. Colonization of Euprymna scolopes bobtail squid by Vibrio fischeri bacteria requires bacterial aggregation in host mucus as the symbiont transitions from a planktonic lifestyle in seawater to a biofilm-associated state in the host. We have identified a gene, binK (biofilm inhibitor kinase; VF_A0360), which encodes an orphan hybrid histidine kinase that negatively regulates the V. fischeri symbiotic biofilm (Syp) in vivo and in vitro We identified binK mutants as exhibiting a colonization advantage in a global genetic screen, a phenotype that we confirmed in controlled competition experiments. Bacterial biofilm aggregates in the host are larger in strains lacking BinK, whereas overexpression of BinK suppresses biofilm formation and squid colonization. Signaling through BinK is required for temperature modulation of biofilm formation at 28°C. Furthermore, we present evidence that BinK acts upstream of SypG, the σ(54)-dependent transcriptional regulator of the syp biofilm locus. The BinK effects are dependent on intact signaling in the RscS-Syp biofilm pathway. Therefore, we propose that BinK antagonizes the signal from RscS and serves as an integral component in V. fischeri biofilm regulation.

IMPORTANCE: Bacterial lifestyle transitions underlie the colonization of animal hosts from environmental reservoirs. Formation of matrix-enclosed, surface-associated aggregates (biofilms) is common in beneficial and pathogenic associations, but investigating the genetic basis of biofilm development in live animal hosts remains a significant challenge. Using the bobtail squid light organ as a model, we analyzed putative colonization factors and identified a histidine kinase that negatively regulates biofilm formation at the host interface. This work reveals a novel in vivo biofilm regulator that influences the transition of bacteria from their planktonic state in seawater to tight aggregates of cells in the host. The study enriches our understanding of biofilm regulation and beneficial colonization by an animal's microbiome.}, } @article {pmid26974534, year = {2017}, author = {Tran, PL and Huynh, E and Pham, P and Lacky, B and Jarvis, C and Mosley, T and Hamood, AN and Hanes, R and Reid, T}, title = {Organoselenium Polymer Inhibits Biofilm Formation in Polypropylene Contact Lens Case Material.}, journal = {Eye & contact lens}, volume = {43}, number = {2}, pages = {110-115}, doi = {10.1097/ICL.0000000000000239}, pmid = {26974534}, issn = {1542-233X}, mesh = {Biofilms/*drug effects ; Contact Lens Solutions/pharmacology ; Contact Lenses/*microbiology ; Equipment Contamination/*prevention & control ; Eye Infections, Bacterial/prevention & control ; Humans ; Organoselenium Compounds/chemistry/*pharmacology ; Polypropylenes/chemistry ; Pseudomonas aeruginosa/drug effects ; Serratia marcescens/drug effects ; Staphylococcus aureus/drug effects ; Stenotrophomonas maltophilia/drug effects ; }, abstract = {OBJECTIVES: Contact lens-acquired bacterial infections are a serious problem. Of the reported cases, inadequate cleaning of the lens case was the most common cause of lens contamination. Organoselenium has been shown to inhibit bacterial attachment to different polymer materials. This study evaluates the ability of an organoselenium monomer, incorporated into the polymer of a polypropylene contact lens case coupon, to block the formation of biofilms in a lens case.

METHODS: The bacteria tested were Pseudomonas aeruginosa, Staphylococcus aureus, Stenotrophomonas maltophilia, and Serratia marcescens. For this study, the bacteria were allowed to grow overnight, in trypticase soy broth media, in the presence of the selenium-containing polymer or the same polymer without organoselenium. The material was studied by both colony-forming unit determination and by confocal laser scanning microscopy.

RESULTS: The results showed that the organoselenium polymer versus the control polymer resulted in the following effect on biofilm formation: (1) a reduction in P. aeruginosa of 7.3 logs (100%); (2) a reduction in S. aureus of 7.3 logs (100%); (3) a reduction in S. maltophilia of 7.5 logs (100%); and (4) a reduction in S. marcescens reduction of 3.3 logs (99.9%). To test the stability of the organoselenium polypropylene contact lens coupon, the coupon was soaked in PBS for eight weeks at room temperature. It was found that when these soaked coupons were tested against S. aureus, complete inhibition (8.1 logs) was obtained. Because organoselenium cannot leach from the polymer, this would imply that the organoselenium polypropylene contact lens case coupon would be inhibitory toward bacterial biofilm for the life of the case.

CONCLUSION: The organoselenium polypropylene contact lens case coupon shows the ability to inhibit biofilm formation. The use of organoselenium copolymer should play an important role in protecting against contact lens case-acquired infection.}, } @article {pmid26973848, year = {2015}, author = {Islam, N and Ross, JM and Marten, MR}, title = {Proteome Analyses of Staphylococcus aureus Biofilm at Elevated Levels of NaCl.}, journal = {Clinical microbiology (Los Angeles, Calif.)}, volume = {4}, number = {5}, pages = {}, pmid = {26973848}, issn = {2327-5073}, support = {R01 AI059369/AI/NIAID NIH HHS/United States ; }, abstract = {Our studies demonstrate that sodium chloride (NaCl) induces changes in biofilm, mediated by increased production of polysaccharides intercellular adhesion (PIA). We identified 12 proteins that showed higher abundance in increased level of NaCl. This includes one important protein (IsaA) known to be associated with biofilm stability. In addition, we also found higher abundance of a cold shock protein, CspA, at higher NaCl. We have also identified several other proteins that are differentially expressed to the elevated levels of NaCl and mapped them in the regulatory pathways of PIA. The majority of proteins are involved with various aspects bacterial metabolic function. Our results demonstrated that NaCl influences gene regulatory networks controlling exopolysaccharide expression.}, } @article {pmid26973606, year = {2016}, author = {Osman, KM and Amer, AM and Badr, JM and Helmy, NM and Elhelw, RA and Orabi, A and Bakry, M and Saad, AS}, title = {Antimicrobial Resistance, Biofilm Formation and mecA Characterization of Methicillin-Susceptible S. aureus and Non-S. aureus of Beef Meat Origin in Egypt.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {222}, pmid = {26973606}, issn = {1664-302X}, abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) have been found in various farm animal species throughout the world. Yet, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible non-S. aureus (MS-NSA), and methicillin-resistant non-S. aureus (MR-NSA) were not investigated. Therefore, we persued to determine the diversity in their phenotypic virulence assay, phenotypic antimicrobial resistance profile and molecular characterization in one of the food chains in Egypt. Samples were collected during 2013 from beef meat at retail. Twenty seven isolates comprising five species (S. hyicus, S. aureus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus) were characterized for their antibiotic resistance phenotypic profile and antibiotic resistance genes (mecA, cfr, gyrA, gyrB, and grlA). Out of the 27 Staphylococcus isolates only one isolate was resistant to the 12 antibiotics representing nine classes. Raw beef meat sold across the Great Cairo zone, contains 66.7% of MRS, with highest prevalence was reported in S. aureus (66.7%), while the MRS non-S. aureus strains constituted 66.7% from which S. hyicus (60%), S. intermedius (33.3%), S. schleiferi subsp. coagulans (100%), and S. lentus (100%) were MRS. Seven S. aureus, six S. hyicus, four S. schleiferi subsp. coagulans, three S. intermedius, and one S. lentus isolates although being resistant to oxacillin yet, 11/27 (40.7%) carried the mecA gene. At the same time, the cfr gene was present in 2 of the nine S. aureus isolates, and totally undetectable in S. hyicus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus. Although, global researches largely focused into MRSA and MR-NSA in animals on pigs, the analysis of our results stipulates, that buffaloes and cattle could be MRSA dispersers and that this theme is not specific to pigs. Detection of MSSA virulence determinants is a must, as although oxacillin resistance may be absent yet, the MSSA may carry the virulence determinants which could be a source of perilous S. aureus for the human community.}, } @article {pmid26973289, year = {2016}, author = {Cui, B and Smooker, PM and Rouch, DA and Deighton, MA}, title = {Effects of erythromycin on the phenotypic and genotypic biofilm expression in two clinical Staphylococcus capitis subspecies and a functional analysis of Ica proteins in S. capitis.}, journal = {Journal of medical microbiology}, volume = {65}, number = {3}, pages = {257}, doi = {10.1099/jmm.0.000223}, pmid = {26973289}, issn = {1473-5644}, } @article {pmid26972979, year = {2016}, author = {Tawakoli, PN and Attin, T and Mohn, D}, title = {Oral biofilm and caries-infiltrant interactions on enamel.}, journal = {Journal of dentistry}, volume = {48}, number = {}, pages = {40-45}, doi = {10.1016/j.jdent.2016.03.006}, pmid = {26972979}, issn = {1879-176X}, mesh = {Actinomyces/drug effects/physiology ; Animals ; Bacterial Load/drug effects ; Biofilms/*drug effects/*growth & development ; Cattle ; Chromatography, High Pressure Liquid/methods ; Dental Caries/*microbiology ; Dental Enamel/diagnostic imaging/*microbiology ; Mass Spectrometry/methods ; Polyethylene Glycols/chemistry/*pharmacology ; Polymethacrylic Acids/chemistry/*pharmacology ; Resins, Synthetic/*chemistry ; Streptococcus mutans/drug effects/physiology ; Streptococcus oralis/drug effects/physiology ; Tooth/microbiology ; Tooth Demineralization ; }, abstract = {OBJECTIVES: This study aimed to analyze interactions between oral biofilms and a dental triethylene glycol dimethacrylate (TEGDMA)-based resin infiltration material on enamel.

METHODS: Demineralized enamel specimens (14 days, acidic buffer, pH 5.0) were either infiltrated with a commercial TEGDMA resin and subjected to a three-species biofilm (Streptococcus mutans UAB 159, Streptococcus oralis OMZ 607 and Actinomyces oris OMZ 745) (group 1), applied to the biofilm (group 2), or merely resin infiltrated (group 3). A control group received no treatment (4). Biofilm formation and metabolic activity of biofilms were measured for group (1) and (2) after 24h CFU and a resazurin assay. Resin biodegradation was measured for group (1) and (3) by high performance liquid chromatography (HPLC) coupled with mass spectrometry after 6 and 24h incubation. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images were taken to study the biofilm and material's autofluorescence in groups (1-4) after 24h.

RESULTS: SEM and CLSM images showed reduced biofilm formation on resin-infiltrated specimens (group 1) compared to group 2, while no biofilm was detectable on groups 3 and 4. CFU data (log10 CFU per mL) of group 1 showed significantly reduced bacterial numbers (p<0.05) compared to group 2. However, HPLC analysis of TEGDMA leakage after 6h and 24h revealed no differences between group 1 and group 3.

CONCLUSIONS: The results of the current study indicate that freshly resin-infiltrated enamel surfaces show a biofilm reducing effect, while monomer leakage was not affected by bacterial presence.

CLINICAL SIGNIFICANCE: Resin infiltrated enamel surfaces are constantly exposed to the oral microflora. Yet, it is not known how biofilms interact with enamel-penetrated resins and if and to which extent accessory alignments in oral hygiene are needed.}, } @article {pmid26969579, year = {2017}, author = {Pleszczyńska, M and Wiater, A and Bachanek, T and Szczodrak, J}, title = {Enzymes in therapy of biofilm-related oral diseases.}, journal = {Biotechnology and applied biochemistry}, volume = {64}, number = {3}, pages = {337-346}, doi = {10.1002/bab.1490}, pmid = {26969579}, issn = {1470-8744}, mesh = {Anti-Bacterial Agents/*therapeutic use ; Bacteria/*growth & development ; Bacterial Adhesion/*drug effects ; Biofilms/*growth & development ; Dental Plaque/drug therapy/microbiology ; Dextranase/*therapeutic use ; Glycoside Hydrolases/*therapeutic use ; Humans ; *Periodontitis/drug therapy/microbiology ; }, abstract = {Biofilm-related infections of the oral cavity, including dental caries and periodontitis, represent the most prevalent health problems. For years, the treatment thereof was largely based on antibacterial chemical agents. Recently, however, there has been growing interest in the application of more preventive and minimally invasive biotechnological methods. This review focuses on the potential applications of enzymes in the treatment and prevention of oral diseases. Dental plaque is a microbial community that develops on the tooth surface, embedded in a matrix of extracellular polymeric substances of bacterial and host origin. Both cariogenic microorganisms and the key components of oral biofilm matrix may be the targets of the enzymes. Oxidative salivary enzymes inhibit or limit the growth of oral pathogens, thereby supporting the natural host defense system; polysaccharide hydrolases (mutanases and dextranases) degrade important carbohydrate components of the biofilm matrix, whereas proteases disrupt bacterial adhesion to oral surfaces or affect cell-cell interactions. The efficiency of the enzymes in in vitro and in vivo studies, advantages and limitations, as well as future perspectives for improving the enzymatic strategy are discussed.}, } @article {pmid26968574, year = {2017}, author = {Hoekstra, MJ and Westgate, SJ and Mueller, S}, title = {Povidone-iodine ointment demonstrates in vitro efficacy against biofilm formation.}, journal = {International wound journal}, volume = {14}, number = {1}, pages = {172-179}, pmid = {26968574}, issn = {1742-481X}, mesh = {Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Humans ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Povidone-Iodine/*pharmacology ; Pseudomonas aeruginosa/*drug effects ; }, abstract = {Anti-infectives used to treat chronic exuding wounds are diluted by wound exudates, absorbed into dressings, metabolised by proteases and destroyed by pH. In order to mimic such effects of exudates, the efficacy of six topical wound agents was assessed undiluted and at 10% concentrations, including povidone-iodine ointment and a silver-impregnated wound dressing, to remove biofilms of Pseudomonas aeruginosa, multi-species biofilms of Candida albicans and methicillin-resistant Staphylococcus aureus (MRSA) in vitro in a Centers for Disease Control and Prevention (CDC) reactor. Povidone-iodine was also diluted to 3·3% and 33·3% of the commercial concentrations. Viable microorganisms in each preparation were quantified by colony count. No viable P. aeruginosa biofilm material was recovered after 4 and 24 hours of treatment with povidone-iodine ointment at the 100% and 10% concentrations. No C. albicans/MRSA biofilm material was recovered after 4 and 24 hours of treatment with povidone-iodine ointment at the 100% concentration. In general, following dilution, povidone-iodine ointment appeared to exhibit greater biofilm removal than the other agents tested. Further research involving different microorganisms in vitro and in vivo over a longer period of time will help elucidate the full potential of povidone-iodine ointment and liposomal hydrogel.}, } @article {pmid26967335, year = {2016}, author = {Murphy, C and Rajabzadeh, AR and Weber, KP and Nivala, J and Wallace, SD and Cooper, DJ}, title = {Nitrification cessation and recovery in an aerated saturated vertical subsurface flow treatment wetland: Field studies and microscale biofilm modeling.}, journal = {Bioresource technology}, volume = {209}, number = {}, pages = {125-132}, doi = {10.1016/j.biortech.2016.02.065}, pmid = {26967335}, issn = {1873-2976}, mesh = {Air ; Biofilms ; Equipment Design ; *Models, Theoretical ; Nitrates/metabolism ; *Nitrification ; Nitrogen/analysis/metabolism ; Oxygen/analysis/metabolism ; Time Factors ; United Kingdom ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Purification/methods ; *Wetlands ; }, abstract = {In aerated treatment wetlands, oxygen availability is not a limiting factor in sustaining a high level of nitrification in wastewater treatment. In the case of an air blower failure, nitrification would cease, potentially causing adverse effects to the nitrifying bacteria. A field trial was completed investigating nitrification loss when aeration is switched off, and the system recovery rate after the aeration is switched back on. Loss of dissolved oxygen was observed to be more rapid than loss of nitrification. Nitrate was observed in the effluent long after the aeration was switched off (48h+). A complementary modeling study predicted nitrate diffusion out of biofilm over a 48h period. After two weeks of no aeration in the established system, nitrification recovered within two days, whereas nitrification establishment in a new system was previously observed to require 20-45days. These results suggest that once established resident nitrifying microbial communities are quite robust.}, } @article {pmid26966998, year = {2016}, author = {Rizzi, V and Fini, P and Semeraro, P and Cosma, P}, title = {Detailed investigation of ROS arisen from chlorophyll a/Chitosan based-biofilm.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {142}, number = {}, pages = {239-247}, doi = {10.1016/j.colsurfb.2016.02.062}, pmid = {26966998}, issn = {1873-4367}, mesh = {Anthracenes/chemistry ; Chitosan/*chemistry ; Chlorophyll/*chemistry ; Chlorophyll A ; Cytochromes c/chemistry ; Fluoresceins/chemistry ; Hydrogen Peroxide/*chemistry ; Light ; Membranes, Artificial ; Photosensitizing Agents/chemistry ; Singlet Oxygen/*chemistry ; Solutions ; Superoxides/*chemistry ; Uric Acid/chemistry ; Water/chemistry ; beta-Cyclodextrins/*chemistry ; }, abstract = {The aim of this work is to study the nature of reactive oxygen species, ROS, arisen from Chitosan/2-HP-β-Cyclodextrin/Chlorophyll a (CH/CD/Chla) blended biofilm under a photodynamic activity. Suitable molecules, called primary acceptors, able to react selectively with ROS, in turn generated by the photosensitizer (PS), herein Chla, are used to attempt this purpose. The changes of the absorption and the emission spectra of these acceptors after the irradiation of aqueous solution containing the active biofilm have provided the specific nature of ROS and thus the main pathway of reaction followed by PS, in our condition. The (1)O2 formation was unveiled using Uric Acid (UA) and 9,10-diphenilanthracene (DPA). On the other hand, 2,7- dichlorofluorescin and Ferricytochrome c (Cyt-c) were used to detect the formation of hydrogen peroxide and superoxide radical anion, respectively. Results suggest that among the possible pathways of reaction, namely Type I and Type II, potentially followed by PSs, in our condition the hybrid biofilm CH/CD/Chla follows mainly Type II mechanism with the formation of (1)O2. However, the latter is involved in subsequent pathway of reaction involving Chla inducing, in addition, the formation of O2(-) and H2O2.}, } @article {pmid26966195, year = {2016}, author = {Schuster, AK and Szewzyk, U}, title = {Draft Genome Sequence of Rheinheimera sp. F8, a Biofilm-Forming Strain Which Produces Large Amounts of Extracellular DNA.}, journal = {Genome announcements}, volume = {4}, number = {2}, pages = {}, pmid = {26966195}, issn = {2169-8287}, abstract = {Rheinheimera sp. strain F8 is a biofilm-forming gammaproteobacterium that has been found to produce large amounts of filamentous extracellular DNA. Here, we announce the de novo assembly of its genome. It is estimated to be 4,464,511 bp in length, with 3,970 protein-coding sequences and 92 RNA-coding sequences.}, } @article {pmid26965870, year = {2016}, author = {Hardy, L and Jespers, V and Abdellati, S and De Baetselier, I and Mwambarangwe, L and Musengamana, V and van de Wijgert, J and Vaneechoutte, M and Crucitti, T}, title = {A fruitful alliance: the synergy between Atopobium vaginae and Gardnerella vaginalis in bacterial vaginosis-associated biofilm.}, journal = {Sexually transmitted infections}, volume = {92}, number = {7}, pages = {487-491}, pmid = {26965870}, issn = {1472-3263}, abstract = {OBJECTIVES: Bacterial vaginosis (BV) is characterised by a change in the microbial composition of the vagina. The BV-associated organisms outnumber the health-associated Lactobacillus species and form a polymicrobial biofilm on the vaginal epithelium, possibly explaining the difficulties with antibiotic treatment. A better understanding of vaginal biofilm with emphasis on Atopobium vaginae and Gardnerella vaginalis may contribute to a better diagnosis and treatment of BV.

METHODS: To this purpose, we evaluated the association between the presence of both bacteria by fluorescence in situ hybridisation (FISH) and BV by Nugent scoring in 463 vaginal slides of 120 participants participating in a clinical trial in Rwanda.

RESULTS: A bacterial biofilm was detected in half of the samples using a universal bacterial probe. The biofilm contained A. vaginae in 54.1% and G. vaginalis in 82.0% of the samples. A. vaginae was accompanied by G. vaginalis in 99.5% of samples. The odds of having a Nugent score above 4 were increased for samples with dispersed G. vaginalis and/or A. vaginae present (OR 4.5; CI 2 to 10.3). The probability of having a high Nugent score was even higher when a combination of adherent G. vaginalis and dispersed A. vaginae was visualised (OR 75.6; CI 13.3 to 429.5) and highest when both bacteria were part of the biofilm (OR 119; CI 39.9 to 360.8).

CONCLUSIONS: Our study, although not comprehensive at studying the polymicrobial biofilm in BV, provided a strong indication towards the importance of A. vaginae and the symbiosis of A. vaginae and G. vaginalis in this biofilm.

TRIAL REGISTRATION NUMBER: NCT01796613.}, } @article {pmid26965863, year = {2016}, author = {Yasa, SR and Kaki, SS and Poornachandra, Y and Kumar, CG and Penumarthy, V}, title = {Synthesis, characterization, antimicrobial and biofilm inhibitory studies of new esterquats.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {26}, number = {8}, pages = {1978-1982}, doi = {10.1016/j.bmcl.2016.03.002}, pmid = {26965863}, issn = {1464-3405}, mesh = {Anti-Bacterial Agents/*chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida/*drug effects/enzymology ; Dose-Response Relationship, Drug ; Esters ; Microbial Sensitivity Tests ; Molecular Structure ; Quaternary Ammonium Compounds/chemical synthesis/chemistry/*pharmacology ; Structure-Activity Relationship ; }, abstract = {Novel esterquats (monoesterquats and diesterquats) were synthesized from 11-bromo undecanoic acid (11-BUA) and different alkyl amines. The prepared compounds were characterized by FT-IR, (1)H NMR, (13)C NMR and mass spectral analysis. 11-BUA was converted into methyl 11-bromo undecanoate which was further converted into amine ester (amine monoester and diester) by reacting with different aliphatic amines (hexyl, dodecyl, octadecyl, dioctyl and dicyclohexyl amine). Finally, the obtained amine esters were converted into esterquats (monoesterquat and diesterquat) by reacting with methyl iodide followed by ion exchange to afford chloride counter ion esterquats (5a-h). The synthesized esterquat products were studied for their antimicrobial and biofilm inhibitory activities. Among all the compounds, amine ester 3a and esterquat 5d showed potent antimicrobial activity towards pathogenic Gram-positive bacterial strains with minimum inhibitory concentration (MIC) values in the range of 3.9-15.6 μg mL(-1) and 1.9-7.8 μg mL(-1), respectively. The esterquat 5d also showed promising antifungal activity against Candida albicans MTCC 3017, Candida albicans MTCC 4748 and Candida aaseri MTCC 1962 strains with MIC value of 7.8 μg mL(-1) which was identical to standard Miconazole. The compounds which exhibited antimicrobial activity were also effective in anti-biofilm activity and it was found that compound 5d exhibited excellent biofilm inhibitory activity with IC50 value of 0.9 μg mL(-1) against Staphylococcus aureus MLS16 MTCC 2940.}, } @article {pmid26963862, year = {2016}, author = {Huang, L and van Loveren, C and Ling, J and Wei, X and Crielaard, W and Deng, DM}, title = {Epithelial cell detachment by Porphyromonas gingivalis biofilm and planktonic cultures.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {489-496}, doi = {10.1080/08927014.2016.1148693}, pmid = {26963862}, issn = {1029-2454}, mesh = {Adhesins, Bacterial/*metabolism ; Bacteriological Techniques/methods ; Biofilms/*growth & development ; Cysteine Endopeptidases/*metabolism ; *Epithelial Cells/microbiology/pathology ; Gingipain Cysteine Endopeptidases ; Humans ; *Periodontal Diseases/diagnosis/microbiology ; *Porphyromonas gingivalis/enzymology/pathogenicity ; Protein Processing, Post-Translational ; }, abstract = {Porphyromonas gingivalis is present as a biofilm at the sites of periodontal infections. The detachment of gingival epithelial cells induced by P. gingivalis biofilms was examined using planktonic cultures as a comparison. Exponentially grown planktonic cultures or 40-h biofilms were co-incubated with epithelial cells in a 24-well plate for 4 h. Epithelial cell detachment was assessed using imaging. The activity of arginine-gingipain (Rgp) and gene expression profiles of P. gingivalis cultures were examined using a gingipain assay and quantitative PCR, respectively. P. gingivalis biofilms induced significantly higher cell detachment and displayed higher Rgp activity compared to the planktonic cultures. The genes involved in gingipain post-translational modification, but not rgp genes, were significantly up-regulated in P. gingivalis biofilms. The results underline the importance of including biofilms in the study of bacterial and host cell interactions.}, } @article {pmid26963754, year = {2016}, author = {Ganjali Dashti, M and Abdeshahian, P and Sudesh, K and Phua, KK}, title = {Optimization of Salmonella Typhi biofilm assay on polypropylene microtiter plates using response surface methodology.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {477-487}, doi = {10.1080/08927014.2015.1135328}, pmid = {26963754}, issn = {1029-2454}, mesh = {*Biofilms/drug effects/growth & development ; *Gallbladder ; Humans ; Microbiological Techniques/methods/standards ; Models, Biological ; Polypropylenes/*chemistry ; Quality Improvement ; *Salmonella typhi/drug effects/physiology ; Surface Properties ; Typhoid Fever/*diagnosis ; }, abstract = {The objective of this study was to develop an optimized assay for Salmonella Typhi biofilm that mimics the environment of the gallbladder as an experimental model for chronic typhoid fever. Multi-factorial assays are difficult to optimize using traditional one-factor-at-a-time optimization methods. Response surface methodology (RSM) was used to optimize six key variables involved in S. Typhi biofilm formation on cholesterol-coated polypropylene 96-well microtiter plates. The results showed that bile (1.22%), glucose (2%), cholesterol (0.05%) and potassium chloride (0.25%) were critical factors affecting the amount of biofilm produced, but agitation (275 rpm) and sodium chloride (0.5%) had antagonistic effects on each other. Under these optimum conditions the maximum OD reading for biofilm formation was 3.4 (λ600 nm), and the coefficients of variation for intra-plate and inter-plate assays were 3% (n = 20) and 5% (n = 8), respectively. These results showed that RSM is an effective approach for biofilm assay optimization.}, } @article {pmid26962315, year = {2016}, author = {Mohammadi-Sichani, M and Karbasizadeh, V and Dokhaharani, SC}, title = {Evaluation of biofilm removal activity of Quercus infectoria galls against Streptococcus mutans.}, journal = {Dental research journal}, volume = {13}, number = {1}, pages = {46-51}, pmid = {26962315}, issn = {1735-3327}, abstract = {BACKGROUND: Dental caries is one of the most prevalent infectious diseases affecting humans of all ages. Streptococcus mutans has an important role in the development of dental caries by acid production. The purpose of this study was to evaluate the antibacterial and biofilm disinfective effects of the oak tree Quercus infectoria galls against S. mutans.

MATERIALS AND METHODS: The bacterial strain used in this study was S. mutans (ATCC: 35668). Two kinds of galls, Mazouj and Ghalghaf were examined. Galls were extracted by methanol, ethanol and acetone by Soxhlet apparatus, separately. Extracts were dissolved in sterile distilled water to a final concentration of 10.00, 5.00, 2.50, 1.25, 0.63, 0.31, and 0.16 mg/ml. Microdilution determined antibacterial activities. The biofilm removal activities of the extracts were examined using crystal violet-stained microtiter plate method. One-way ANOVA was used to compare biofilm formation in the presence or absence of the extracts.

RESULTS: The methanolic, ethanolic, and acetonic extracts of Q. infectoria galls showed the strong inhibitory effects on S. mutans (P < 0.05). The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values for the Mazouj and Ghalghaf gall extracts against S. mutans were identical. The MIC values ranged from 160 μg/ml to 320 μg/ml, whereas the MBC values ranged from 320 μg/ml to 640 μg/ml. All extracts of Q. infectoria galls significantly (P < 0.05) reduced biofilm biomass of S. mutans at the concentrations higher than 9.8 μg/ml.

CONCLUSION: Three different extracts of Q. infectoria galls were similar in their antibacterial activity against S. mutans. These extracts had the highest biofilm removal activities at 312.5 μg/ml concentration. The galls of Q. infectoria are potentially good sources of antibacterial and biofilm disinfection agent.}, } @article {pmid26962018, year = {2016}, author = {Ferrer, MD and Mira, A}, title = {Oral Biofilm Architecture at the Microbial Scale.}, journal = {Trends in microbiology}, volume = {24}, number = {4}, pages = {246-248}, doi = {10.1016/j.tim.2016.02.013}, pmid = {26962018}, issn = {1878-4380}, mesh = {Bacteria/*classification ; Humans ; *Microbiota ; Mouth/*microbiology ; *Phylogeography ; }, abstract = {The application of Spectral Imaging FISH to oral biofilm samples has permitted the direct, simultaneous observation of up to nine different bacterial taxa. This has revealed a complex yet organized microbial architecture, identifying the key microorganisms in the community and detecting the existing interspecies physical interactions at the micron scale.}, } @article {pmid26961464, year = {2016}, author = {Song, Z and Sun, H and Yang, Y and Jing, H and Yang, L and Tong, Y and Wei, C and Wang, Z and Zou, Q and Zeng, H}, title = {Enhanced efficacy and anti-biofilm activity of novel nanoemulsions against skin burn wound multi-drug resistant MRSA infections.}, journal = {Nanomedicine : nanotechnology, biology, and medicine}, volume = {12}, number = {6}, pages = {1543-1555}, doi = {10.1016/j.nano.2016.01.015}, pmid = {26961464}, issn = {1549-9642}, mesh = {Anti-Bacterial Agents ; Anti-Infective Agents/*administration & dosage ; *Biofilms ; Burns/drug therapy/*microbiology ; Emulsions ; Humans ; *Methicillin-Resistant Staphylococcus aureus ; *Nanoparticles ; Staphylococcal Infections ; }, abstract = {Multi-drug resistant MRSA (methicillin-resistant Staphylococcus aureus) is a global problem for human health, especially skin burn wound patients. Therefore, we estimated the antibacterial and anti-biofilm activity of a chlorhexidine acetate nanoemulsion (CNE) by previously ourselves designed against skin burn wound MRSA infections. Compared with its water solution (CHX), CNE showed a better and faster action against MRSA both in vitro and in vivo. Importantly, CNE was more effective at inhibiting biofilm formation and clearing the biofilm. We also found that the cell walls and membranes of MRSA were severely disrupted after treatment with CNE. Moreover, the relative electrical conductivity and the leakage of alkaline phosphates, K(+), Mg(2+), DNA and protein obviously increased because the cell wall and membrane were damaged. These data show that novel CNE is a promising potential antimicrobial candidate, especially for skin burn wound MRSA infections.}, } @article {pmid26960943, year = {2016}, author = {Tsui, C and Kong, EF and Jabra-Rizk, MA}, title = {Pathogenesis of Candida albicans biofilm.}, journal = {Pathogens and disease}, volume = {74}, number = {4}, pages = {ftw018}, pmid = {26960943}, issn = {2049-632X}, support = {DE14424/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Antifungal Agents/classification/pharmacology/therapeutic use ; Bacterial Infections/microbiology ; *Biofilms/drug effects/growth & development ; Candida albicans/drug effects/*physiology ; Candidiasis/drug therapy/*microbiology ; Coinfection ; Disease Models, Animal ; Drug Resistance, Fungal ; Extracellular Matrix/immunology/metabolism ; Fungal Polysaccharides/immunology/metabolism ; Gene Expression Regulation, Fungal ; Humans ; Microbial Interactions ; Mucous Membrane/microbiology ; }, abstract = {Candida albicans is the most common human fungal pathogen causing diseases ranging from mucosal to systemic infections. As a commensal, C. albicans asymptomatically colonizes mucosal surfaces; however, any disruption in the host environment or under conditions of immune dysfunction, C. albicans can proliferate and invade virtually any site in the host. The ability of this highly adaptable fungal species to transition from commensal to pathogen is due to a repertoire of virulence factors. Specifically, the ability to switch morphology and form biofilms are properties central to C. albicans pathogenesis. In fact, the majority of C. albicans infections are associated with biofilm formation on host or abiotic surfaces such as indwelling medical devices, which carry high morbidity and mortality. Significantly, biofilms formed by C. albicans are inherently tolerant to antimicrobial therapy and therefore, the susceptibility of Candida biofilms to the current therapeutic agents remains low. The aim of this review is to provide an overview of C. albicans highlighting some of the diverse biofilm-associated diseases caused by this opportunistic pathogen and the animal models available to study them. Further, the classes of antifungal agents used to combat these resilient infections are discussed along with mechanisms of drug resistance.}, } @article {pmid26960360, year = {2016}, author = {Ariafar, MN and Buzrul, S and Akçelik, N}, title = {Modeling and predicting the biofilm formation of Salmonella Virchow with respect to temperature and pH.}, journal = {Acta biologica Hungarica}, volume = {67}, number = {1}, pages = {99-111}, doi = {10.1556/018.67.2016.1.8}, pmid = {26960360}, issn = {0236-5383}, mesh = {Biofilms/*growth & development ; Hydrogen-Ion Concentration ; *Models, Biological ; Salmonella/*physiology ; Temperature ; }, abstract = {Biofilm formation of Salmonella Virchow was monitored with respect to time at three different temperature (20, 25 and 27.5 °C) and pH (5.2, 5.9 and 6.6) values. As the temperature increased at a constant pH level, biofilm formation decreased while as the pH level increased at a constant temperature, biofilm formation increased. Modified Gompertz equation with high adjusted determination coefficient (Radj(2)) and low mean square error (MSE) values produced reasonable fits for the biofilm formation under all conditions. Parameters of the modified Gompertz equation could be described in terms of temperature and pH by use of a second order polynomial function. In general, as temperature increased maximum biofilm quantity, maximum biofilm formation rate and time of acceleration of biofilm formation decreased; whereas, as pH increased; maximum biofilm quantity, maximum biofilm formation rate and time of acceleration of biofilm formation increased. Two temperature (23 and 26 °C) and pH (5.3 and 6.3) values were used up to 24 h to predict the biofilm formation of S. Virchow. Although the predictions did not perfectly match with the data, reasonable estimates were obtained. In principle, modeling and predicting the biofilm formation of different microorganisms on different surfaces under various conditions could be possible.}, } @article {pmid26958458, year = {2016}, author = {Azimi, S and Kafil, HS and Baghi, HB and Shokrian, S and Najaf, K and Asgharzadeh, M and Yousefi, M and Shahrivar, F and Aghazadeh, M}, title = {Presence of exoY, exoS, exoU and exoT genes, antibiotic resistance and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran.}, journal = {GMS hygiene and infection control}, volume = {11}, number = {}, pages = {Doc04}, pmid = {26958458}, issn = {2196-5226}, abstract = {BACKGROUND: Pseudomonas aeruginosa, as Gram-negative rod bacilli, has an important role in human infection. In the present study we aimed to investigate the presence of exo genes and biofilm production among Pseudomonas aeruginosa isolates in Northwest Iran.

MATERIAL AND METHODS: 160 isolates of P. aeruginosa were collected and identified by biochemical tests and were characterized for antibiotic resistance. Biofilm production was evaluated by microtiter plate assay and the presence of exo genes was evaluated by allele-specific PCR (polymerase chain reaction). Chi-square test was used for statistical analysis.

RESULTS: The most effective antibiotics against isolates were colistin and polymyxin B. 87% of the isolates were biofilm producers of which 69% were strongly biofilm producers. 55% of the isolates carried exoY, 52% of the isolates carried exoU, and 26.3% and 5% carried exoS and exoT, respectively.

CONCLUSION: Our findings showed different distribution of exo genes in clinical isolates of P. aeruginosa in Northwest Iran. ExoS and exoU were more prevalent in non-biofilm producers and exoY was more prevalent in biofilm producer isolates. These results might indicate the importance of exoY in biofilm production of Pseudomonas aeruginosa.}, } @article {pmid26957787, year = {2016}, author = {Palaniswamy, U and Lakkam, SR and Arya, S and Aravelli, S}, title = {Effectiveness of N-acetyl cysteine, 2% chlorhexidine, and their combination as intracanal medicaments on Enterococcus faecalis biofilm.}, journal = {Journal of conservative dentistry : JCD}, volume = {19}, number = {1}, pages = {17-20}, pmid = {26957787}, issn = {0972-0707}, abstract = {AIM: The purpose of this study was to evaluate the antibacterial efficacies of 2% chlorhexidine (CHX), N-acetyl cysteine (NAC) and assess their synergistic or antagonist action as intracanal medicament.

MATERIALS AND METHODS: Agar diffusion test was performed with 2% CHX, NAC, and their combination against E. faecalis planktonic cells. The diameters of the zones of bacterial inhibition were measured and recorded for each solution. The assay was further extended to 2 weeks old E. faecalis dentinal biofilm. Sixteen freshly extracted teeth were vertically sectioned into two halves resulting in a total of 32 samples. The samples were inoculated with bacterial suspension and incubated at 37°C for 2 weeks for biofilm formation. The samples were then divided into four experimental groups with 8 samples in each group. The samples were gently washed in saline and placed in culture wells containing the test solutions, i.e., 2% CHX, NAC, a combination of 2% CHX and NAC in 1:1 ratio, and a control group containing saline. The biofilm formed on the root canal surface were removed with a sterile scalpel and inoculated on blood agar plates to check for the formation of E. faecalis colonies.

STATISTICAL ANALYSIS: For agar diffusion test, data were analyzed statistically using one-way analysis of variance and then by post-hoc Scheffe's test to compare the antimicrobial efficacy between the groups. Statistical analysis was not done for the cultures obtained from the biofilm as there was no growth in all the three test groups except the control group, i.e., saline.

RESULTS: In agar diffusion test, among the three groups tested, 2% CHX and NAC showed almost equal zones of inhibition whereas maximum inhibition was shown by a combination of NAC and 2% CHX suggesting a synergistic action. The results obtained were highly significant (P < 0.001) for the combination of medicament when compared to individual test group. In culture analysis, which was done for the biofilm, no growth was observed in all the three test groups. The results obtained were biologically significant but statistically insignificant.

CONCLUSION: NAC has almost equal antimicrobial property as 2% CHX whereas their combination showed a synergistic action.}, } @article {pmid26957546, year = {2016}, author = {Wang, Y and Andole Pannuri, A and Ni, D and Zhou, H and Cao, X and Lu, X and Romeo, T and Huang, Y}, title = {Structural Basis for Translocation of a Biofilm-supporting Exopolysaccharide across the Bacterial Outer Membrane.}, journal = {The Journal of biological chemistry}, volume = {291}, number = {19}, pages = {10046-10057}, pmid = {26957546}, issn = {1083-351X}, support = {R01 GM059969/GM/NIGMS NIH HHS/United States ; R01 GM066794/GM/NIGMS NIH HHS/United States ; }, mesh = {Acetylation ; Amidohydrolases/*chemistry/metabolism ; Bacterial Outer Membrane Proteins/*chemistry/metabolism ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Cell Membrane/*metabolism ; Crystallography, X-Ray ; Escherichia coli/growth & development/*metabolism ; Escherichia coli Proteins/*chemistry/metabolism ; Immunoblotting ; Polymers/chemistry ; Polysaccharides, Bacterial/*metabolism ; Protein Conformation ; }, abstract = {The partially de-N-acetylated poly-β-1,6-N-acetyl-d-glucosamine (dPNAG) polymer serves as an intercellular biofilm adhesin that plays an essential role for the development and maintenance of integrity of biofilms of diverse bacterial species. Translocation of dPNAG across the bacterial outer membrane is mediated by a tetratricopeptide repeat-containing outer membrane protein, PgaA. To understand the molecular basis of dPNAG translocation, we determined the crystal structure of the C-terminal transmembrane domain of PgaA (residues 513-807). The structure reveals that PgaA forms a 16-strand transmembrane β-barrel, closed by four loops on the extracellular surface. Half of the interior surface of the barrel that lies parallel to the translocation pathway is electronegative, suggesting that the corresponding negatively charged residues may assist the secretion of the positively charged dPNAG polymer. In vivo complementation assays in a pgaA deletion bacterial strain showed that a cluster of negatively charged residues proximal to the periplasm is necessary for biofilm formation. Biochemical analyses further revealed that the tetratricopeptide repeat domain of PgaA binds directly to the N-deacetylase PgaB and is critical for biofilm formation. Our studies support a model in which the positively charged PgaB-bound dPNAG polymer is delivered to PgaA through the PgaA-PgaB interaction and is further targeted to the β-barrel lumen of PgaA potentially via a charge complementarity mechanism, thus priming the translocation of dPNAG across the bacterial outer membrane.}, } @article {pmid26957413, year = {2017}, author = {Kariu, T and Nakao, R and Ikeda, T and Nakashima, K and Potempa, J and Imamura, T}, title = {Inhibition of gingipains and Porphyromonas gingivalis growth and biofilm formation by prenyl flavonoids.}, journal = {Journal of periodontal research}, volume = {52}, number = {1}, pages = {89-96}, pmid = {26957413}, issn = {1600-0765}, support = {R01 DE009761/DE/NIDCR NIH HHS/United States ; R01 DE022597/DE/NIDCR NIH HHS/United States ; }, mesh = {Adhesins, Bacterial/*drug effects ; Biofilms/drug effects/*growth & development ; Cysteine Endopeptidases/*drug effects ; Epimedium/metabolism ; Flavonoids/isolation & purification/*pharmacology ; Gingipain Cysteine Endopeptidases ; Porphyromonas gingivalis/drug effects/*growth & development/metabolism ; Prenylation ; }, abstract = {BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis is considered a major pathogen of chronic periodontitis, which also may be implicated with systemic diseases such as atherosclerosis. Secreted cysteine proteases, gingipains Rgp and Kgp, are essential for P. gingivalis virulence. Some polyphenols and flavonoids are known to inhibit gingipain activity and interfere with biofilm formation by P. gingivalis. Many bioactive compounds have been isolated from Epimedium species, but availability of these compounds on gingipains and P. gingivalis is still unclear. Therefore, the aim of this study was to evaluate natural products from medical plants to develop a new therapeutic agent against periodontal disease.

MATERIAL AND METHODS: Prenylated flavonoids were isolated from Epimedium species plant using column chromatographies. The inhibitory effect of the prenylated flavonoids against protease activity of gingipains were examined using purified gingipains and fluorogenic substrates. Anti-P. gingivalis activity was evaluated to analyze planktonic growth and biofilm formation in brain heart infusion medium in the presence of the prenylated flavonoids.

RESULTS: We isolated 17 prenylated flavonoids (Limonianin, Epimedokoreanin B, etc.) from Epimedium species. We found that some prenylated flavonoids inhibited gingipain activity in a non-competitive manner with Ki values at μm order. The prenylated flavonoids also hindered growth and biofilm formation of P. gingivalis, in a manner independent of gingipain inhibition by the compounds.

CONCLUSION: The results indicated an inhibitory effect of the prenylated flavonoids against P. gingivalis and would provide useful information for future development of periodontitis treatment that suppresses gingipains, P. gingivalis growth and biofilm formation.}, } @article {pmid26955044, year = {2016}, author = {Kim, MH}, title = {Nanoparticle-Based Therapies for Wound Biofilm Infection: Opportunities and Challenges.}, journal = {IEEE transactions on nanobioscience}, volume = {15}, number = {3}, pages = {294-304}, pmid = {26955044}, issn = {1558-2639}, support = {R01 NR015674/NR/NINR NIH HHS/United States ; }, mesh = {Animals ; *Anti-Bacterial Agents/chemistry/pharmacology/therapeutic use ; Biofilms/*drug effects ; Humans ; Mice ; Nanomedicine/*methods ; *Nanoparticles/chemistry/therapeutic use ; Wound Healing/*drug effects ; Wound Infection/*drug therapy ; }, abstract = {Clinical data from human chronic wounds implicates biofilm formation with the onset of wound chronicity. Despite the development of novel antimicrobial agents, the cost and complexity of treating chronic wound infections associated with biofilms remain a serious challenge, which necessitates the development of new and alternative approaches for effective anti-biofilm treatment. Recent advancement in nanotechnology for developing a new class of nanoparticles that exhibit unique chemical and physical properties holds promise for the treatment of biofilm infections. Over the last decade, nanoparticle-based approaches against wound biofilm infection have been directed toward developing nanoparticles with intrinsic antimicrobial properties, utilizing nanoparticles for controlled antimicrobials delivery, and applying nanoparticles for antibacterial hyperthermia therapy. In addition, a strategy to functionalize nanoparticles towards enhanced penetration through the biofilm matrix has been receiving considerable interest recently by means of achieving an efficient targeting to the bacterial cells within biofilm matrix. This review summarizes and highlights the recent development of these nanoparticle-based approaches as potential therapeutics for controlling wound biofilm infection, along with current challenges that need to be overcome for their successful clinical translation.}, } @article {pmid26953602, year = {2016}, author = {Michael, V and Frank, O and Bartling, P and Scheuner, C and Göker, M and Brinkmann, H and Petersen, J}, title = {Biofilm plasmids with a rhamnose operon are widely distributed determinants of the 'swim-or-stick' lifestyle in roseobacters.}, journal = {The ISME journal}, volume = {10}, number = {10}, pages = {2498-2513}, pmid = {26953602}, issn = {1751-7370}, mesh = {Bacterial Proteins/genetics/metabolism ; *Biofilms ; Molecular Sequence Data ; *Operon ; Phylogeny ; Plasmids/*genetics/metabolism ; Replicon ; Rhamnose/*metabolism ; Roseobacter/classification/genetics/isolation & purification/*physiology ; }, abstract = {Alphaproteobacteria of the metabolically versatile Roseobacter group (Rhodobacteraceae) are abundant in marine ecosystems and represent dominant primary colonizers of submerged surfaces. Motility and attachment are the prerequisite for the characteristic 'swim-or-stick' lifestyle of many representatives such as Phaeobacter inhibens DSM 17395. It has recently been shown that plasmid curing of its 65-kb RepA-I-type replicon with >20 genes for exopolysaccharide biosynthesis including a rhamnose operon results in nearly complete loss of motility and biofilm formation. The current study is based on the assumption that homologous biofilm plasmids are widely distributed. We analyzed 33 roseobacters that represent the phylogenetic diversity of this lineage and documented attachment as well as swimming motility for 60% of the strains. All strong biofilm formers were also motile, which is in agreement with the proposed mechanism of surface attachment. We established transposon mutants for the four genes of the rhamnose operon from P. inhibens and proved its crucial role in biofilm formation. In the Roseobacter group, two-thirds of the predicted biofilm plasmids represent the RepA-I type and their physiological role was experimentally validated via plasmid curing for four additional strains. Horizontal transfer of these replicons was documented by a comparison of the RepA-I phylogeny with the species tree. A gene content analysis of 35 RepA-I plasmids revealed a core set of genes, including the rhamnose operon and a specific ABC transporter for polysaccharide export. Taken together, our data show that RepA-I-type biofilm plasmids are essential for the sessile mode of life in the majority of cultivated roseobacters.}, } @article {pmid26953206, year = {2016}, author = {Li, X and Lu, N and Brady, HR and Packman, AI}, title = {Ureolytic Biomineralization Reduces Proteus mirabilis Biofilm Susceptibility to Ciprofloxacin.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {5}, pages = {2993-3000}, pmid = {26953206}, issn = {1098-6596}, support = {P30 CA060553/CA/NCI NIH HHS/United States ; R01 AI081983/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Humans ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Proteus mirabilis/*drug effects ; }, abstract = {Ureolytic biomineralization induced by urease-producing bacteria, particularly Proteus mirabilis, is responsible for the formation of urinary tract calculi and the encrustation of indwelling urinary catheters. Such microbial biofilms are challenging to eradicate and contribute to the persistence of catheter-associated urinary tract infections, but the mechanisms responsible for this recalcitrance remain obscure. In this study, we characterized the susceptibility of wild-type (ure+) and urease-negative (ure-) P. mirabilis biofilms to killing by ciprofloxacin. Ure+ biofilms produced fine biomineral precipitates that were homogeneously distributed within the biofilm biomass in artificial urine, while ure- biofilms did not produce biomineral deposits under identical growth conditions. Following exposure to ciprofloxacin, ure+ biofilms showed greater survival (less killing) than ure- biofilms, indicating that biomineralization protected biofilm-resident cells against the antimicrobial. To evaluate the mechanism responsible for this recalcitrance, we observed and quantified the transport of Cy5-conjugated ciprofloxacin into the biofilm by video confocal microscopy. These observations revealed that the reduced susceptibility of ure+ biofilms resulted from hindered delivery of ciprofloxacin into biomineralized regions of the biofilm. Further, biomineralization enhanced retention of viable cells on the surface following antimicrobial exposure. These findings together show that ureolytic biomineralization induced by P. mirabilis metabolism strongly regulates antimicrobial susceptibility by reducing internal solute transport and increasing biofilm stability.}, } @article {pmid26952720, year = {2016}, author = {Lu, H and Xiong, J and Shang, Q and Jiang, Y and Cao, Y}, title = {Roles of RPS41 in Biofilm Formation, Virulence, and Hydrogen Peroxide Sensitivity in Candida albicans.}, journal = {Current microbiology}, volume = {72}, number = {6}, pages = {783-787}, pmid = {26952720}, issn = {1432-0991}, mesh = {Animals ; *Biofilms ; Candida albicans/drug effects/genetics/*pathogenicity/*physiology ; Candidiasis/*microbiology ; Fungal Proteins/genetics/*metabolism ; Gene Expression Regulation, Fungal/drug effects ; Humans ; Hydrogen Peroxide/*pharmacology ; Mice ; Virulence/drug effects ; }, abstract = {In eukaryotes, loss of cytoplasmic ribosomal proteins (RPs) results in a reduced growth rate and other phenotypic defects. The ability to transition from a unicellular budding yeast to a filamentous form is very important for biofilm formation and virulence in Candida albicans. Our recent study found that loss of the RPS41 (C2_10620W_A) gene but not its paralog RPS42 (C1_01640W_A) resulted in altered growth and filamentation changes in C. albicans, so we hypothesized that the RPS41 gene should play important roles in virulence and biofilm formation in this pathogen. We found that both virulence and the ability to form biofilms were defective due to deletion of the RPS41 gene. We also found that loss of the RPS41 gene increased sensitivity to hydrogen peroxide, and that hydrogen peroxide induced the expression of the RPS41 gene in a wild-type strain. These results suggested that the RPS41 gene plays important roles in C. albicans biofilm formation, virulence, and susceptibility to hydrogen peroxide.}, } @article {pmid26951960, year = {2016}, author = {Guo, W and Quah, SY and Lim, KC and Yu, VS and Tan, KS}, title = {Cysteamine Enhances Biofilm Eradication Efficacy of Calcium Hydroxide.}, journal = {Journal of endodontics}, volume = {42}, number = {5}, pages = {742-746}, doi = {10.1016/j.joen.2016.01.020}, pmid = {26951960}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Load/drug effects ; Biofilms/*drug effects ; Calcium Hydroxide/*pharmacology ; Chlorhexidine/pharmacology ; Cysteamine/administration & dosage/*pharmacology ; Dentin/drug effects ; *Drug Combinations ; *Drug Synergism ; Enterococcus faecalis/drug effects ; Expectorants ; Materials Testing ; Microbial Viability/drug effects ; Microscopy, Confocal ; Root Canal Irrigants/administration & dosage/pharmacology ; }, abstract = {INTRODUCTION: Calcium hydroxide (Ca[OH]2) is a widely used interappointment dressing, but its antibacterial property is compromised by dentin. Hence, the addition of chlorhexidine (CHX) with Ca(OH)2 has been proposed. However, the antimicrobial efficacy of this mixture compared with Ca(OH)2 alone is currently still debatable. Cysteamine is a mucolytic agent used to reduce the viscosity of mucus through the disruption of proteins, which are also important components of the extracellular matrix of biofilms. The aims of this study were to determine the efficacy of cysteamine alone and in combination with Ca(OH)2 to eradicate Enterococcus faecalis biofilm compared with CHX with Ca(OH)2, and to determine if this effect is affected by dentin.

METHODS: The biofilm eradication efficacies of Ca(OH)2 alone and with cysteamine were determined using 7-day E. faecalis biofilm cultured on dentin discs and compared with Ca(OH)2 with 2% CHX. The effects of dentin on the efficacies of Ca(OH)2 alone and with either cysteamine or CHX were examined.

RESULTS: Cysteamine alone completely abolished E. faecalis biofilm at 200 mg/mL. The combination of Ca(OH)2 with either cysteamine at 10 mg/mL or 2% CHX completely obliterated E. faecalis biofilm. Cysteamine with Ca(OH)2 completely eradicated E. faecalis biofilm despite preincubation with dentin, whereas CHX with Ca(OH)2 was less effective.

CONCLUSIONS: Cysteamine effectively eliminated E. faecalis biofilm and showed synergistic effects in combination with Ca(OH)2, which were unaffected by dentin. Hence, our findings support the use of cysteamine as a potential adjunct to Ca(OH)2 as an interappointment dressing.}, } @article {pmid26950795, year = {2016}, author = {Kim, YS and Kang, SM and Lee, ES and Lee, JH and Kim, BR and Kim, BI}, title = {Ecological changes in oral microcosm biofilm during maturation.}, journal = {Journal of biomedical optics}, volume = {21}, number = {10}, pages = {101409}, doi = {10.1117/1.JBO.21.10.101409}, pmid = {26950795}, issn = {1560-2281}, mesh = {Animals ; Bacteria/*chemistry ; Biofilms/*growth & development ; Cattle ; DNA, Bacterial/*analysis ; Humans ; Image Processing, Computer-Assisted ; Models, Biological ; Saliva/microbiology ; Spectrometry, Fluorescence/*methods ; Tooth/microbiology ; }, abstract = {The aim of this study was to evaluate the ecological changes in the biofilm at different stages of maturation using 16S rDNA gene amplicon sequencing and to identify correlations between red/green (R/G) fluorescence ratio and ecological changes. An oral microcosm biofilm was initiated from the saliva of a single donor and grown anaerobically for up to 10 days in basal medium mucin. Quantitative light-induced fluorescence analysis was shown that the R/G ratio of the biofilm increased consistently, but the slope rapidly decreased after six days. The bacterial compositions of 10 species also consistently changed over time. However, there was no significant correlation between each bacteria and red fluorescence. The monitoring of the maturation process of oral microcosm biofilm over 10 days revealed that the R/G ratio and the bacterial composition within biofilm consistently changed. Therefore, the R/G fluorescence ratio of biofilm may be related with its ecological change rather than specific bacteria}, } @article {pmid26950587, year = {2016}, author = {Ge, X and Shi, X and Shi, L and Liu, J and Stone, V and Kong, F and Kitten, T and Xu, P}, title = {Involvement of NADH Oxidase in Biofilm Formation in Streptococcus sanguinis.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0151142}, pmid = {26950587}, issn = {1932-6203}, support = {R01 DE023078/DE/NIDCR NIH HHS/United States ; R01DE018138/DE/NIDCR NIH HHS/United States ; R01DE023078/DE/NIDCR NIH HHS/United States ; R56AI085195/AI/NIAID NIH HHS/United States ; 5 P30 NS047463/NS/NINDS NIH HHS/United States ; R56 AI085195/AI/NIAID NIH HHS/United States ; P30 CA016059/CA/NCI NIH HHS/United States ; P30 NS047463/NS/NINDS NIH HHS/United States ; R01 DE018138/DE/NIDCR NIH HHS/United States ; }, mesh = {Biofilms/*growth & development ; DNA, Bacterial/metabolism ; Extracellular Space/metabolism ; Fatty Acids/chemistry/metabolism ; Membrane Fluidity ; Multienzyme Complexes/genetics/*metabolism ; Mutation ; NADH, NADPH Oxidoreductases/genetics/*metabolism ; Streptococcus sanguis/cytology/*enzymology/genetics/*physiology ; }, abstract = {Biofilms play important roles in microbial communities and are related to infectious diseases. Here, we report direct evidence that a bacterial nox gene encoding NADH oxidase is involved in biofilm formation. A dramatic reduction in biofilm formation was observed in a Streptococcus sanguinis nox mutant under anaerobic conditions without any decrease in growth. The membrane fluidity of the mutant bacterial cells was found to be decreased and the fatty acid composition altered, with increased palmitic acid and decreased stearic acid and vaccenic acid. Extracellular DNA of the mutant was reduced in abundance and bacterial competence was suppressed. Gene expression analysis in the mutant identified two genes with altered expression, gtfP and Idh, which were found to be related to biofilm formation through examination of their deletion mutants. NADH oxidase-related metabolic pathways were analyzed, further clarifying the function of this enzyme in biofilm formation.}, } @article {pmid26948126, year = {2016}, author = {Ghasemian, A and Najar Peerayeh, S and Bakhshi, B and Mirzaee, M}, title = {Comparison of Biofilm Formation between Methicillin-Resistant and Methicillin-Susceptible Isolates of Staphylococcus aureus.}, journal = {Iranian biomedical journal}, volume = {20}, number = {3}, pages = {175-181}, pmid = {26948126}, issn = {2008-823X}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Methicillin/pharmacology ; *Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus/genetics/*growth & development/isolation & purification ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; }, abstract = {BACKGROUND: The aim of this study was to compare the biofilm formation and the prevalence of biofilm-associated genes between the isolates of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus.

METHODS: In total, 209 S. aureus isolates were collected. The antibiotic susceptibility test was conducted using nine antibiotics according to the guidelines of Clinical and Laboratory Standards Institute. Phenotypic biofilm formation was performed with microtiter plate assay. The polymerase chain reaction was employed to detect icaA, icaD, icaB, icaC, clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, bbp, mecA, and SCCmec types as well as agr group genes with specific primers.

RESULTS: Sixty-four (30.62%) isolates were resistant to methicillin, and 54 (83%) MRSA harbored SCCmec III. Furthermore, 122 (58.3%) isolates belonged to agr group I. Twenty-six (36.1%) MRSA and 42 (28.9%) MSSA isolates were strong biofilm producers (no significant difference). The prevalence of icaA, icaD, icaB, and icaC genes in MSSA isolates was 71, 41, 76, and 72%, respectively. The frequency of clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, and bbp in MSSA was 100, 100, 56, 46, 74, 54, 78, 11, and 1%, respectively. However, in MRSA isolates, the frequency was 97, 97, 64, 51, 76, 56, 79, and 12% with no track of bbp, respectively.

CONCLUSION: Statistical difference between MSSA and MRSA regarding biofilm formation and the frequency of all biofilm-encoding genes was not significant. The majority of the S. aureus isolates harbored clfA, clfB, eno, fib, icaA, and icaD genes.}, } @article {pmid26946303, year = {2016}, author = {Van Hoecke, H and De Paepe, AS and Lambert, E and Van Belleghem, JD and Cools, P and Van Simaey, L and Deschaght, P and Vaneechoutte, M and Dhooge, I}, title = {Haemophilus influenzae biofilm formation in chronic otitis media with effusion.}, journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery}, volume = {273}, number = {11}, pages = {3553-3560}, pmid = {26946303}, issn = {1434-4726}, mesh = {Adenoids/microbiology ; Biofilms/*growth & development ; Child ; Child, Preschool ; Chronic Disease ; Ear, Middle/microbiology ; Female ; Genotype ; Haemophilus influenzae/isolation & purification/*physiology ; Humans ; In Situ Hybridization, Fluorescence ; Infant ; Male ; Microscopy, Confocal ; Moraxella catarrhalis/isolation & purification/physiology ; Otitis Media with Effusion/*microbiology ; Staphylococcus aureus/isolation & purification/physiology ; Streptococcus pneumoniae/isolation & purification/physiology ; }, abstract = {Otitis media with effusion (OME) is a highly prevalent disease in children, but the exact pathogenesis and role of bacteria are still not well understood. This study aimed to investigate the presence of otopathogenic bacteria in the middle ear effusion (MEE) and adenoid of children with chronic OME (COME), and to investigate in vivo whether these bacteria, especially Haemophilus influenzae, are organized as a biofilm in the middle ear fluid. MEE and adenoid samples were collected from 21 patients with COME. Extensive bacterial culturing and genotyping was performed on all middle ear and adenoid samples. Fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) was used to visualize possible biofilm structures for a selection of middle ear effusion samples. 34 MEE samples were collected from 21 patients of which 64.7 % were culture positive for bacteria and 47.0 % were culture positive for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and/or Streptococcus pneumoniae. All 21 adenoid samples were culture positive for one or more of these four otopathogens. H. influenzae (35.3 %) and S. pneumoniae (76.2 %) were the most frequently cultured bacteria in the MEE and adenoid samples, respectively. The same bacterial species was found in MEE and adenoid for 84.6 % of the patients and in 81.2 % of the cases where the same species was found in more than one site it involved the same bacterial genotype. FISH and CLSM demonstrated the presence of H. influenzae specific biofilm structures in five of the eight culture positive MEEs that were tested, but in none of the two culture negative MEEs. The findings in this study indicate that the adenoid acts as a reservoir for bacteria in MEE and confirms that biofilms, in at least half of the cases consisting of H. influenzae, are indeed present in the MEE of children with COME. Biofilms may thus play a crucial role in the pathogenesis of COME, which is important in the understanding of this disease and the development of potential future treatment options.}, } @article {pmid26945736, year = {2016}, author = {Holban, AM and Gestal, MC and Grumezescu, AM}, title = {Control of biofilm-associated infections by signaling molecules and nanoparticles.}, journal = {International journal of pharmaceutics}, volume = {510}, number = {2}, pages = {409-418}, doi = {10.1016/j.ijpharm.2016.02.044}, pmid = {26945736}, issn = {1873-3476}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Bacteria/*drug effects ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Humans ; Nanoparticles/*chemistry ; Nanostructures/*chemistry ; Nanotechnology/methods ; }, abstract = {As the severe infections caused by resistant pathogens and biofilm embedded bacteria continue to emerge, alternative antimicrobial strategies could represent a solution. Recent studies support the development of molecular approaches (through signaling molecules) aiming to fight infections by modulating the virulence, behavior and formation of resistance structures such as biofilms. The utilization of such formulations would offer the advantage of reducing the selection of resistant isolates, since most of the proposed molecules do not interfere with the population fitness if utilized in low amounts. Despite the promising results, these therapies are delaying to be applied in the clinical context mainly because of the following: (i) limited knowledge regarding their long and medium term effect, (ii) specific properties that make most of these molecules difficult to be utilized in pharmacological formulations, (iii) low stability, (iv) difficulty to reach a target within the host body, and (v) limited availability. For reducing most of these disadvantages, nanotechnology seem to offer the best option through the development of nanostructured materials and nanoparticles able to improve the efficiency of molecular virulence modulators and novel antimicrobial compounds and to ensure their targeted delivery and controlled release.}, } @article {pmid26945590, year = {2016}, author = {Gowrishankar, S and Sivaranjani, M and Kamaladevi, A and Ravi, AV and Balamurugan, K and Karutha Pandian, S}, title = {Cyclic dipeptide cyclo(l-leucyl-l-prolyl) from marine Bacillus amyloliquefaciens mitigates biofilm formation and virulence in Listeria monocytogenes.}, journal = {Pathogens and disease}, volume = {74}, number = {4}, pages = {ftw017}, doi = {10.1093/femspd/ftw017}, pmid = {26945590}, issn = {2049-632X}, mesh = {Anti-Bacterial Agents/biosynthesis/pharmacology ; Bacillus amyloliquefaciens/*physiology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Dipeptides/biosynthesis/*pharmacology ; Dose-Response Relationship, Drug ; Listeria monocytogenes/*drug effects/*physiology ; *Microbial Interactions ; Microbial Sensitivity Tests ; Peptides, Cyclic/biosynthesis/*pharmacology ; Quantitative Trait, Heritable ; Virulence/drug effects ; }, abstract = {This study was intentionally focused on cyclo(l-leucyl-l-prolyl) (CLP), a cyclic dipeptide with myriad pharmaceutical significance, to explore its antivirulence efficacy against the predominant foodborne pathogen,Listeria monocytogenes(LM). Minimum inhibitory concentration (MIC) of CLP against LM ATCC 19111 was found to be 512 μg mL(-1) CLP at sub-MICs (64 128, 256 μg mL(-1)) demonstrated a profound non-bactericidal dose-dependent antibiofilm efficacy (on polystyrene and glass) against LM, which was further confirmed through confocal and scanning electron microscopic analysis (on stainless steel surface).In vitrobioassays divulged the phenomenal inhibitory efficacy of CLP towards various virulence traits of LM, specifically its overwhelming suppression of swimming and swarming motility. Data ofin vivoassay usingCaenorhabditis eleganssignified that the plausible mechanism of CLP could be by impeding the pathogen's initial adhesion and thereby attenuating the biofilm assemblage and its associated virulence. This was further confirmed by significant decrease in extracellular polymeric substance, autoaggregation, hydrophobicity index and extracellular DNA of the CLP-treated LM cells. Collectively, this study unveils the antivirulence efficacy of CLP against the Gram-positive foodborne pathogen and the strainBacillus amyloliquefaciensaugurs well to be a promising probiotic in controlling infections associated with LM.}, } @article {pmid26945171, year = {2016}, author = {Cavalcanti, YW and Wilson, M and Lewis, M and Williams, D and Senna, PM and Del-Bel-Cury, AA and da Silva, WJ}, title = {Salivary pellicles equalise surfaces' charges and modulate the virulence of Candida albicans biofilm.}, journal = {Archives of oral biology}, volume = {66}, number = {}, pages = {129-140}, doi = {10.1016/j.archoralbio.2016.02.016}, pmid = {26945171}, issn = {1879-1506}, mesh = {Acrylic Resins/chemistry ; Biofilms/drug effects/*growth & development ; Candida albicans/cytology/genetics/pathogenicity/*physiology ; Dental Pellicle/*microbiology/physiology ; Fungal Proteins/genetics ; Humans ; Imaging, Three-Dimensional ; In Vitro Techniques ; Microbial Viability ; Microscopy, Electron, Scanning ; Polymethyl Methacrylate/chemistry ; Random Allocation ; Salivary Proteins and Peptides/chemistry ; Surface Properties ; Titanium/chemistry ; Virulence ; }, abstract = {INTRODUCTION: Numerous environmental factors influence the pathogenesis of Candida biofilms and an understanding of these is necessary for appropriate clinical management.

AIMS: To investigate the role of material type, pellicle and stage of biofilm development on the viability, bioactivity, virulence and structure of C. albicans biofilms.

METHODS: The surface roughness (SR) and surface free energy (SFE) of acrylic and titanium discs was measured. Pellicles of saliva, or saliva supplemented with plasma, were formed on acrylic and titanium discs. Candida albicans biofilms were then generated for 1.5 h, 24h, 48 h and 72 h. The cell viability in biofilms was analysed by culture, whilst DNA concentration and the expression of Candida virulence genes (ALS1, ALS3 and HWP1) were evaluated using qPCR. Biofilm metabolic activity was determined using XTT reduction assay, and biofilm structure analysed by Scanning Electron Microscopy (SEM).

RESULTS: Whilst the SR of acrylic and titanium did not significantly differ, the saliva with plasma pellicle increased significantly the total SFE of both surface. The number of viable microorganisms and DNA concentration increased with biofilm development, not differing within materials and pellicles. Biofilms developed on saliva with plasma pellicle surfaces had significantly higher activity after 24h and this was accompanied with higher expression of virulence genes at all periods.

CONCLUSION: Induction of C. albicans virulence occurs with the presence of plasma proteins in pellicles, throughout biofilm growth. To mitigate such effects, reduction of increased plasmatic exudate, related to chronic inflammatory response, could aid the management of candidal biofilm-related infections.}, } @article {pmid26944848, year = {2016}, author = {Li, X and Chopp, DL and Russin, WA and Brannon, PT and Parsek, MR and Packman, AI}, title = {In Situ Biomineralization and Particle Deposition Distinctively Mediate Biofilm Susceptibility to Chlorine.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {10}, pages = {2886-2892}, pmid = {26944848}, issn = {1098-5336}, support = {R01 AI081983/AI/NIAID NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Chlorine/*pharmacology ; Disinfectants/*pharmacology ; Microbial Viability/drug effects ; Minerals/*metabolism ; Pseudomonas aeruginosa/*drug effects/metabolism/*physiology ; }, abstract = {Microbial biofilms and mineral precipitation commonly co-occur in engineered water systems, such as cooling towers and water purification systems, and both decrease process performance. Microbial biofilms are extremely challenging to control and eradicate. We previously showed that in situ biomineralization and the precipitation and deposition of abiotic particles occur simultaneously in biofilms under oversaturated conditions. Both processes could potentially alter the essential properties of biofilms, including susceptibility to biocides. However, the specific interactions between mineral formation and biofilm processes remain poorly understood. Here we show that the susceptibility of biofilms to chlorination depends specifically on internal transport processes mediated by biomineralization and the accumulation of abiotic mineral deposits. Using injections of the fluorescent tracer Cy5, we show that Pseudomonas aeruginosa biofilms are more permeable to solutes after in situ calcite biomineralization and are less permeable after the deposition of abiotically precipitated calcite particles. We further show that biofilms are more susceptible to chlorine killing after biomineralization and less susceptible after particle deposition. Based on these observations, we found a strong correlation between enhanced solute transport and chlorine killing in biofilms, indicating that biomineralization and particle deposition regulate biofilm susceptibility by altering biocide penetration into the biofilm. The distinct effects of in situ biomineralization and particle deposition on biocide killing highlight the importance of understanding the mechanisms and patterns of biomineralization and scale formation to achieve successful biofilm control.}, } @article {pmid26943932, year = {2016}, author = {Faridnasr, M and Ghanbari, B and Sassani, A}, title = {Optimization of the moving-bed biofilm sequencing batch reactor (MBSBR) to control aeration time by kinetic computational modeling: Simulated sugar-industry wastewater treatment.}, journal = {Bioresource technology}, volume = {208}, number = {}, pages = {149-160}, doi = {10.1016/j.biortech.2016.02.047}, pmid = {26943932}, issn = {1873-2976}, mesh = {Biofilms ; *Bioreactors ; Carbohydrates ; *Food-Processing Industry ; Industrial Waste ; Kinetics ; *Models, Theoretical ; Waste Disposal, Fluid/*instrumentation/methods ; Wastewater/chemistry ; }, abstract = {A novel approach was applied for optimization of a moving-bed biofilm sequencing batch reactor (MBSBR) to treat sugar-industry wastewater (BOD5=500-2500 and COD=750-3750 mg/L) at 2-4 h of cycle time (CT). Although the experimental data showed that MBSBR reached high BOD5 and COD removal performances, it failed to achieve the standard limits at the mentioned CTs. Thus, optimization of the reactor was rendered by kinetic computational modeling and using statistical error indicator normalized root mean square error (NRMSE). The results of NRMSE revealed that Stover-Kincannon (error=6.40%) and Grau (error=6.15%) models provide better fits to the experimental data and may be used for CT optimization in the reactor. The models predicted required CTs of 4.5, 6.5, 7 and 7.5 h for effluent standardization of 500, 1000, 1500 and 2500 mg/L influent BOD5 concentrations, respectively. Similar pattern of the experimental data also confirmed these findings.}, } @article {pmid26943591, year = {2016}, author = {Laube, N and Desai, C and Bernsmann, F}, title = {Hydrophobic forces as a key factor in crystalline biofilm formation on ureteral stents.}, journal = {Biomedizinische Technik. Biomedical engineering}, volume = {61}, number = {5}, pages = {483-490}, doi = {10.1515/bmt-2015-0160}, pmid = {26943591}, issn = {1862-278X}, mesh = {Biofilms/*drug effects ; Crystallins ; Hydrophobic and Hydrophilic Interactions ; Polyurethanes/*chemistry ; *Stents ; Surface Properties/*drug effects ; Ureter ; }, abstract = {BACKGROUND: Current discussions about biofilm formation focus on the solid/liquid interface between a medical device and body fluids. Yet it has been shown that gas bubbles (GB) can stably form on ureteral stents in artificial urine and that their fate depends on the stent's surface properties. The liquid/gas interface constitutes an adhesion site for precipitating salts as well as hydrophobic organic molecules.

MATERIALS AND METHODS: The surface wettability of polyurethane stents is varied by coating with amorphous hydrogenated carbon (a-C:H). GB and crystalline biofilm formation on the stents are investigated in a novel encrustation device which avoids gravitation- or sample-position-related influences on the results.

RESULTS: Bigger and more stable GB form on hydrophobic stents than on hydrophilic, coated stents. Appearance and amount of crystalline deposits differ significantly between the surfaces. With decreasing wettability the number of hollow crystalline spheres and the mass of precipitate increase.

CONCLUSIONS: On hydrophobic surfaces, stable GB increase precipitation of salts and become incorporated in the growing encrustation layer in vitro. In contrast, GB quickly lift off from hydrophilic surfaces taking part of the precipitate with them. This self-cleaning mechanism slows down the encrustation process. A similar effect may explain the prolonged complication-free indwelling time of amorphous-carbon coated stents in vivo.}, } @article {pmid26940589, year = {2016}, author = {Sarkar, S and Vagenas, D and Schembri, MA and Totsika, M}, title = {Biofilm formation by multidrug resistant Escherichia coli ST131 is dependent on type 1 fimbriae and assay conditions.}, journal = {Pathogens and disease}, volume = {74}, number = {3}, pages = {}, doi = {10.1093/femspd/ftw013}, pmid = {26940589}, issn = {2049-632X}, mesh = {Adhesins, Escherichia coli/genetics/metabolism ; Adult ; Anti-Bacterial Agents/pharmacology ; Bacteriuria/*microbiology ; Biofilms/*growth & development ; Drug Resistance, Multiple, Bacterial ; Escherichia coli/classification/*drug effects/isolation & purification/*pathogenicity ; Escherichia coli Infections/microbiology ; Female ; Fimbriae Proteins/antagonists & inhibitors/genetics/metabolism ; Fimbriae, Bacterial/*classification ; Humans ; Urinary Tract Infections/microbiology ; }, abstract = {Escherichia coli sequence type 131 (ST131) has emerged as a pandemic lineage of important multidrug resistant pathogens worldwide. Despite many studies examining the epidemiology of ST131, only a few studies to date have investigated the capacity of ST131 strains to form biofilms. Some of these studies have reported contrasting findings, with no specific ST131 biofilm-promoting factors identified. Here, we examined a diverse collection of ST131 isolates for in vitro biofilm formation in different media and assay conditions, including urine from healthy adult women. We found significant differences among strains and assay conditions, which offers an explanation for the contrasting findings reported by previous studies using a single condition. Importantly, we showed that expression of type 1 fimbriae is a critical determinant for biofilm formation by ST131 strains and that inhibition of the FimH adhesin significantly reduces biofilm formation. We also offer direct genetic evidence for the contribution of type 1 fimbriae in biofilm formation by the reference ST131 strain EC958, a representative of the clinically dominant H30-Rx ST131 subgroup. This is the first study of ST131 biofilm formation in biologically relevant conditions and paves the way for the application of FimH inhibitors in treating drug resistant ST131 biofilm infections.}, } @article {pmid26940526, year = {2016}, author = {Zhu, B and Liu, C and Liu, S and Cong, H and Chen, Y and Gu, L and Ma, LZ}, title = {Membrane association of SadC enhances its diguanylate cyclase activity to control exopolysaccharides synthesis and biofilm formation in Pseudomonas aeruginosa.}, journal = {Environmental microbiology}, volume = {18}, number = {10}, pages = {3440-3452}, doi = {10.1111/1462-2920.13263}, pmid = {26940526}, issn = {1462-2920}, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Cell Membrane/enzymology/genetics/*metabolism ; Cyclic GMP/metabolism ; Escherichia coli Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Phosphorus-Oxygen Lyases/genetics/*metabolism ; Polysaccharides, Bacterial/*biosynthesis ; Pseudomonas aeruginosa/cytology/*enzymology/genetics/physiology ; }, abstract = {Cyclic diguanosine monophosphate (c-di-GMP) is one of the most important bacterial second messengers that controls many bacterial cellular functions including lifestyle switch between plankton and biofilm. Surface attachment defective (SadC) is a diguanylate cyclase (DGC) involved in the biosynthesis of c-di-GMP in Pseudomonas aeruginosa, an opportunistic pathogen that can cause diverse infections. Here we report the crystal structure of GGDEF domain from SadC and the critical role of the trans-membrane (TM) domain of SadC with regard to biofilm formation, exopolysaccharide production and motility. We showed that over-expression of SadC in P. aeruginosa PAO1 totally inhibited swimming motility and significantly enhanced the production of exopolysaccharide Psl. SadC lacking TM domains (SadC300-487) could not localize on cytoplasmic membrane and form cluster, lost the ability to inhibit the swimming and twitching motility, and showed the attenuated activity to promote Psl production despite that SadC300-487 was able to catalyze the synthesize of c-di-GMP in vitro and in vivo. The GGDEF domain of SadC has a typical GGDEF structure and the α-helix connected the TM domains with SadC GGDEF domain is essential for SadC to form DGC oligomers. Our data imply that membrane association of SadC promotes its DGC activity by affecting the formation of active DGC oligomers.}, } @article {pmid26940291, year = {2016}, author = {Dworniczek, E and Plesch, G and Seniuk, A and Adamski, R and Michal, R and Čaplovičová, M}, title = {Photo-catalytic inactivation of an Enterococcus biofilm: the anti-microbial effect of sulphated and europium-doped titanium dioxide nanopowders.}, journal = {FEMS microbiology letters}, volume = {363}, number = {7}, pages = {}, doi = {10.1093/femsle/fnw051}, pmid = {26940291}, issn = {1574-6968}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Catalysis ; Enterococcus/*drug effects/ultrastructure ; Europium/chemistry/pharmacology ; Luminescent Agents/chemistry/pharmacology ; *Microbial Viability ; Microscopy, Electron, Transmission ; Nanoparticles/*chemistry/ultrastructure ; Photosensitizing Agents/*pharmacology ; Sulfates/chemistry ; Superoxides/metabolism ; Titanium/*pharmacology ; }, abstract = {The control and prevention of biofilm-related infections is an important public healthcare issue. Given the increasing antibiotic resistance among bacteria and fungi that cause serious infections in humans, promotion of new strategies combating microorganisms has been essential. One attractive approach to inactivate microorganisms is the use of semiconductor photo-catalysis, which has become the subject of extensive research. In this study, the bactericidal properties of four photo-catalysts, TiO2, TiO2-S, TiO2-Eu and TiO2-Eu-S, were investigated against established 24, 48, 72 and 96 h biofilms of Enterococcus The exposure of biofilms to the catalysts induced the production of superoxide radical anions. The best photo-catalytic inactivation was achieved with the TiO2-Eu-S and TiO2-S nanopowders and 24 h biofilms. Transmission electron microscopy images showed significant changes in the structure of the biofilm cells following photo-inactivation. The results suggest that doping with europium and modifying the surface with sulphate groups enhanced the bactericidal activity of the TiO2 nanoparticles against enterococcal biofilms.}, } @article {pmid26939983, year = {2016}, author = {Rajalaxmi, M and Beema Shafreen, R and Iyer, PM and Sahaya Vino, R and Balamurugan, K and Pandian, SK}, title = {An in silico, in vitro and in vivo investigation of indole-3-carboxaldehyde identified from the seawater bacterium Marinomonas sp. as an anti-biofilm agent against Vibrio cholerae O1.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {1-12}, doi = {10.1080/08927014.2016.1154545}, pmid = {26939983}, issn = {1029-2454}, mesh = {Animals ; *Anti-Bacterial Agents/biosynthesis/pharmacology ; *Biofilms/drug effects/growth & development ; Caenorhabditis elegans/drug effects/physiology ; Cholera/drug therapy/microbiology ; *Indoles/metabolism/pharmacology ; Marinomonas/*metabolism ; Quorum Sensing ; *Vibrio cholerae O1/drug effects/pathogenicity/physiology ; Virulence/drug effects ; }, abstract = {Biofilm formation is a major contributing factor in the pathogenesis of Vibrio cholerae O1 (VCO1) and therefore preventing biofilm formation could be an effective alternative strategy for controlling cholera. The present study was designed to explore seawater bacteria as a source of anti-biofilm agents against VCO1. Indole-3-carboxaldehyde (I3C) was identified as an active principle component in Marinomonas sp., which efficiently inhibited biofilm formation by VCO1 without any selection pressure. Furthermore, I3C applications also resulted in considerable collapsing of preformed pellicles. Real-time PCR studies revealed the down-regulation of virulence gene expression by modulation of the quorum-sensing pathway and enhancement of protease production, which was further confirmed by phenotypic assays. Furthermore, I3C increased the survival rate of Caenorhabditis elegans when infected with VCO1 by significantly reducing in vivo biofilm formation, which was corroborated by a survivability assay. Thus, this study revealed, for the first time, the potential of I3C as an anti-biofilm agent against VCO1.}, } @article {pmid26939844, year = {2016}, author = {Gismondi, A and Pippo, FD and Bruno, L and Antonaroli, S and Congestri, R}, title = {Phosphorus removal coupled to bioenergy production by three cyanobacterial isolates in a biofilm dynamic growth system.}, journal = {International journal of phytoremediation}, volume = {18}, number = {9}, pages = {869-876}, doi = {10.1080/15226514.2016.1156640}, pmid = {26939844}, issn = {1549-7879}, mesh = {Anabaena/metabolism ; *Biofilms ; Biofuels/*analysis ; Cyanobacteria/*physiology ; Nostoc/metabolism ; Phosphorus/*metabolism ; Waste Disposal, Fluid/*methods ; Wastewater/analysis ; Water Pollutants, Chemical/*metabolism ; }, abstract = {In the present study a closed incubator, designed for biofilm growth on artificial substrata, was used to grow three isolates of biofilm-forming heterocytous cyanobacteria using an artificial wastewater secondary effluent as the culture medium. We evaluated biofilm efficiency in removing phosphorus, by simulating biofilm-based tertiary wastewater treatment and coupled this process with biodiesel production from the developed biomass. The three strains were able to grow in the synthetic medium and remove phosphorus in percentages, between 6 and 43%, which varied between strains and also among each strain according to the biofilm growth phase. Calothrix sp. biofilm turned out to be a good candidate for tertiary treatment, showing phosphorus reducing capacity (during the exponential biofilm growth) at the regulatory level for the treated effluent water being discharged into natural water systems. Besides phosphorus removal, the three cyanobacterial biofilms produced high quality lipids, whose profile showed promising chemical stability and combustion behavior. Further integration of the proposed processes could include the integration of oil extracted from these cyanobacterial biofilms with microalgal oil known for high monounsaturated fatty acids content, in order to enhance biodiesel cold flow characteristics.}, } @article {pmid26939806, year = {2016}, author = {Harris, D and Ummadi, JG and Thurber, AR and Allau, Y and Verba, C and Colwell, F and Torres, ME and Koley, D}, title = {Real-time monitoring of calcification process by Sporosarcina pasteurii biofilm.}, journal = {The Analyst}, volume = {141}, number = {10}, pages = {2887-2895}, doi = {10.1039/c6an00007j}, pmid = {26939806}, issn = {1364-5528}, mesh = {Biofilms/*growth & development ; Calcium Carbonate/*analysis ; Chemical Precipitation ; Sporosarcina/*growth & development ; Urease/*analysis ; }, abstract = {Sporosarcina pasteurii is known to produce calcite or biocement in the presence of urea and Ca(2+). Herein, we report the use of novel ultramicrosensors such as pH, Ca(2+), and redox sensors, along with a scanning electrochemical microscope (SECM), to monitor a real-time, bacteria-mediated urea hydrolysis process and subsequent changes in morphology due to CaCO3 precipitation. We report that the surface pH of a live biofilm changed rapidly from 7.4 to 9.2 within 2 min, whereas similar fast depletion (10 min) of Ca(2+) was observed from 85 mM to 10 mM in the presence of a high urea (10 g L(-1)) brine solution at 23 °C. Both the pH and the Ca(2+) concentration profiles were extended up to 600 μm from the biofilm surface, whereas the bulk chemical composition of the brine solution remained constant over the entire 4 h of SECM experiments. In addition, we observed a change in biofilm surface morphology and an increase in overall biofilm height of 50 μm after 4 h of precipitation. Electron microscopy confirmed the changes in surface morphology and formation of CaCO3 crystals. Development of the Ca(2+) profile took 10 min, whereas that of the pH profile took 2 min. This finding indicates that the initial urea hydrolysis process is fast and limited by urease or number of bacteria, whereas later CaCO3 formation and growth of crystals is a slow chemical process. The ultramicrosensors and approaches employed here are capable of accurately characterizing bioremediation on temporal and spatial scales pertinent to the microbial communities and the processes they mediate.}, } @article {pmid26939451, year = {2015}, author = {Qiao, R and Xie, K and Xie, M}, title = {[Progress in gene regulation mechanisms of Staphylococcus biofilm development--A review].}, journal = {Wei sheng wu xue bao = Acta microbiologica Sinica}, volume = {55}, number = {10}, pages = {1238-1244}, pmid = {26939451}, issn = {0001-6209}, mesh = {Bacterial Proteins/*genetics/metabolism ; *Biofilms/growth & development ; *Gene Expression Regulation ; Gene Expression Regulation, Developmental ; Staphylococcus/*genetics/growth & development/physiology ; }, abstract = {Bacterial resistance is a threat to public health. Bacterial biofilm formation is one of the main reasons for persistent infection caused by bacteria. Biofilm development is a complex process that involves many factors and genes which play various roles in all stages of the biofilm formation. This review focuses on the gene regulatory mechanisms relate to the biofilm formation of Staphylococcus, the most common pathogen that causes nosocomial infection, as well as the latest developments of pharmacological anti-biofilm therapies. We also address new strategy to treat bacterial infection and the development of drugs and vaccines against biofilm resistance.}, } @article {pmid26938657, year = {2016}, author = {Dai, Y and Chan, Y and Jiang, B and Wang, L and Zou, J and Pan, K and Fu, H}, title = {Bifunctional Ag/Fe/N/C Catalysts for Enhancing Oxygen Reduction via Cathodic Biofilm Inhibition in Microbial Fuel Cells.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {11}, pages = {6992-7002}, doi = {10.1021/acsami.5b11561}, pmid = {26938657}, issn = {1944-8252}, mesh = {*Bioelectric Energy Sources ; *Biofilms ; Carbon/*chemistry ; Catalysis ; Iron/*chemistry ; Nitrogen/*chemistry ; Oxidation-Reduction ; Oxygen/*chemistry ; Silver/*chemistry ; }, abstract = {Limitation of the oxygen reduction reaction (ORR) in single-chamber microbial fuel cells (SC-MFCs) is considered an important hurdle in achieving their practical application. The cathodic catalysts faced with a liquid phase are easily primed with the electrolyte, which provides more surface area for bacterial overgrowth, resulting in the difficulty in transporting protons to active sites. Ag/Fe/N/C composites prepared from Ag and Fe-chelated melamine are used as antibacterial ORR catalysts for SC-MFCs. The structure-activity correlations for Ag/Fe/N/C are investigated by tuning the carbonization temperature (600-900 °C) to clarify how the active-constituents of Ag/Fe and N-species influence the antibacterial and ORR activities. A maximum power density of 1791 mW m(-2) is obtained by Ag/Fe/N/C (630 °C), which is far higher than that of Pt/C (1192 mW m(-2)), only having a decline of 16.14% after 90 days of running. The Fe-bonded N and the cooperation of pyridinic N and pyrrolic N in Ag/Fe/N/C contribute equally to the highly catalytic activity toward ORR. The ·OH or O2(-) species originating from the catalysis of O2 can suppress the biofilm growth on Ag/Fe/N/C cathodes. The synergistic effects between the Ag/Fe heterojunction and N-species substantially contribute to the high power output and Coulombic efficiency of Ag/Fe/N/C catalysts. These new antibacterial ORR catalysts show promise for application in MFCs.}, } @article {pmid26936213, year = {2016}, author = {Oliveira, RR and Fermiano, D and Feres, M and Figueiredo, LC and Teles, FR and Soares, GM and Faveri, M}, title = {Levels of Candidate Periodontal Pathogens in Subgingival Biofilm.}, journal = {Journal of dental research}, volume = {95}, number = {6}, pages = {711-718}, pmid = {26936213}, issn = {1544-0591}, support = {R01 DE024767/DE/NIDCR NIH HHS/United States ; U01 DE021127/DE/NIDCR NIH HHS/United States ; }, mesh = {Aggressive Periodontitis/*microbiology ; Bacteria/*classification ; Bacteroides/classification ; Bacteroidetes/classification ; Biofilms/*classification ; Chronic Periodontitis/*microbiology ; Dental Plaque/*microbiology ; Humans ; Microbiota ; }, abstract = {In recent years, several new periodontal taxa have been associated with the etiology of periodontitis. A recent systematic review provides further support for the pathogenic role of 17 species/phylotypes. Thus, the aim of this study was to assess the prevalence and levels of these species in subjects with generalized chronic periodontitis (GChP; n = 30), generalized aggressive periodontitis (GAgP; n = 30), and periodontal health (PH; n = 30). All subjects underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes through the RNA-oligonucleotide quantification technique. Subjects from the GChP and GAgP groups presented the highest mean values for all clinical parameters in comparison with the PH group (P < 0.05). Subjects with GChP and GAgP showed significantly higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360, and TM7 sp. HOT 356 phylotypes, as well as higher mean levels of Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas gingivalis, Tannerella forsythia, and Selenomonas sputigena species than PH subjects (P < 0.05). GAgP subjects presented higher mean levels of TM7 sp. HOT 356 and F. alocis than GChP subjects (P < 0.05). A significantly higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, and Fretibacterium sp. HOT 362 was found in subjects with GChP and GAgP than in PH subjects. Mean levels of P. gingivalis (r = 0.68), T. forsythia (r = 0.62), F. alocis (r = 0.51, P = 0.001), and Fretibacterium sp. HOT 360 (r = 0.41) were correlated with pocket depth (P < 0.001). In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, and TM7 sp. HOT 356 phylotypes, in addition to F. alocis, F. fastidiosum, and S. sputigena, seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated.}, } @article {pmid26936153, year = {2016}, author = {Howery, KE and Clemmer, KM and Rather, PN}, title = {The Rcs regulon in Proteus mirabilis: implications for motility, biofilm formation, and virulence.}, journal = {Current genetics}, volume = {62}, number = {4}, pages = {775-789}, pmid = {26936153}, issn = {1432-0983}, mesh = {Bacterial Proteins/genetics/*metabolism ; Base Sequence ; Binding Sites ; Biofilms ; Cell Division ; Gene Expression Regulation, Bacterial ; Mutation ; Operon ; Promoter Regions, Genetic ; Protein Binding ; Proteus mirabilis/pathogenicity/*physiology ; *Signal Transduction ; Transcriptional Activation ; Virulence/genetics ; }, abstract = {The overall role of the Rcs phosphorelay in Proteus mirabilis is largely unknown. Previous work had demonstrated that the Rcs phosphorelay represses the flhDC operon and activates the minCDE cell division inhibition system. To identify additional cellular functions regulated by the Rcs phosphorelay, an analysis of RNA-seq data was undertaken. In this report, the results of the RNA-sequencing are discussed with an emphasis on the predicted roles of the Rcs phosphorelay in swarmer cell differentiation, motility, biofilm formation, and virulence. RcsB is shown to activate genes important for differentiation and fimbriae formation, while repressing the expression of genes important for motility and virulence. Additionally, to follow up on the RNA-Seq data, we demonstrate that an rcsB mutant is deficient in its ability to form biofilm and exhibits enhanced virulence in a Galleria mellonella waxworm model. Overall, these results indicate the Rcs regulon in P. mirabilis extends beyond flagellar genes to include those involved in biofilm formation and virulence. Furthermore, the information presented in this study may provide clues to additional roles of the Rcs phosphorelay in other members of the Enterobacteriaceae.}, } @article {pmid26936123, year = {2016}, author = {Baragi, LV and Anil, AC}, title = {Synergistic effect of elevated temperature, pCO2 and nutrients on marine biofilm.}, journal = {Marine pollution bulletin}, volume = {105}, number = {1}, pages = {102-109}, doi = {10.1016/j.marpolbul.2016.02.049}, pmid = {26936123}, issn = {1879-3363}, mesh = {Biofilms/drug effects/*growth & development ; Carbon Dioxide/*analysis ; Environmental Monitoring ; Nitrogen/analysis ; Phosphorus/analysis ; *Temperature ; Water Pollutants, Chemical/*analysis ; }, abstract = {Natural marine biofilms provide signatures of the events that occur over a period of time and can be used as bioindicators of environmental changes. Hence, the effects of temperature (30 and 34°C), pCO2 (400 and 1500μatm) and nutrients (unenriched and enriched f/2 media) on the marine biofilm were evaluated using a 2×2×2 factorial design. In unenriched condition, acidification significantly increased the abundance of phytoperiphytes whereas reduced that of bacteria and it was vice versa in the enriched condition. Warming had significant negative effect on the abundance of both phytoperiphytes and bacteria, except in unenriched condition wherein it favoured bacterial growth. Synergistically, acidification and warming had deleterious effects resulting in further reduction in the abundance of both phytoperiphytes and bacteria, except in enriched condition wherein bacterial abundance increased. Such changes in biofilm communities in response to warming and acidification can have cascading effect on the subsequent build-up of macrofouling community.}, } @article {pmid26934196, year = {2016}, author = {Barbosa, JO and Rossoni, RD and Vilela, SF and de Alvarenga, JA and Velloso, Mdos S and Prata, MC and Jorge, AO and Junqueira, JC}, title = {Streptococcus mutans Can Modulate Biofilm Formation and Attenuate the Virulence of Candida albicans.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0150457}, pmid = {26934196}, issn = {1932-6203}, mesh = {Animals ; Biofilms/*growth & development ; Candida albicans/*growth & development/*pathogenicity ; Candidiasis/microbiology ; Disease Models, Animal ; Humans ; Larva/microbiology ; Lepidoptera/microbiology ; *Microbial Interactions ; Streptococcus mutans/*physiology ; }, abstract = {Streptococcus mutans and Candida albicans are found together in the oral biofilms on dental surfaces, but little is known about the ecological interactions between these species. Here, we studied the effects of S. mutans UA159 on the growth and pathogencity of C. albicans. Initially, the effects of S. mutans on the biofilm formation and morphogenesis of C. albicans were tested in vitro. Next, we investigate the influence of S. mutans on pathogenicity of C. albicans using in vivo host models, in which the experimental candidiasis was induced in G. mellonella larvae and analyzed by survival curves, C. albicans count in hemolymph, and quantification of hyphae in the host tissues. In all the tests, we evaluated the direct effects of S. mutans cells, as well as the indirect effects of the subproducts secreted by this microorganism using a bacterial culture filtrate. The in vitro analysis showed that S. mutans cells favored biofilm formation by C. albicans. However, a reduction in biofilm viable cells and inhibition of hyphal growth was observed when C. albicans was in contact with the S. mutans culture filtrate. In the in vivo study, injection of S. mutans cells or S. mutans culture filtrate into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, a reduction in hyphal formation was observed in larval tissues when C. albicans was associated with S. mutans culture filtrate. These findings suggest that S. mutans can secrete subproducts capable to inhibit the biofilm formation, morphogenesis and pathogenicity of C. albicans, attenuating the experimental candidiasis in G. mellonella model.}, } @article {pmid26932953, year = {2016}, author = {Galli, J and Calò, L and Giuliani, M and Sergi, B and Lucidi, D and Meucci, D and Bassotti, E and Sanguinetti, M and Paludetti, G}, title = {Biofilm's Role in Chronic Cholesteatomatous Otitis Media: A Pilot Study.}, journal = {Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery}, volume = {154}, number = {5}, pages = {914-916}, doi = {10.1177/0194599816630548}, pmid = {26932953}, issn = {1097-6817}, mesh = {*Biofilms ; Cholesteatoma, Middle Ear/*microbiology ; Chronic Disease ; Female ; Humans ; Male ; Microscopy, Electron, Scanning ; Middle Aged ; Otitis Media/*microbiology ; Pilot Projects ; }, abstract = {Cholesteatoma is a destructive lesion involving the temporal bone, which may induce severe complications due to its expansion and erosion of adjacent structures. Bacterial biofilm plays a crucial role in the pathogenesis of many otolaryngologic inflammatory/infectious chronic diseases. In this pilot study, we investigated, by means of cultural examination and with scanning electron microscope, the presence of bacterial biofilm in a series of samples from the epitympanic and mastoid region in patients affected by cholesteatoma and from the promontory region in patients with healthy mucosa who were undergoing to stapes surgery. The preliminary data support the association between biofilm and cholesteatoma (81.3% of the cases) and allow us to hypothesize that keratinized matrix of cholesteatoma may represent the ideal substrate for biofilm colonization and survival; this finding is consistent with the clinical course of aural cholesteatoma, characterized by recurrent exacerbations and recalcitrant course.}, } @article {pmid26931773, year = {2017}, author = {Freire, MO and Devaraj, A and Young, A and Navarro, JB and Downey, JS and Chen, C and Bakaletz, LO and Zadeh, HH and Goodman, SD}, title = {A bacterial-biofilm-induced oral osteolytic infection can be successfully treated by immuno-targeting an extracellular nucleoid-associated protein.}, journal = {Molecular oral microbiology}, volume = {32}, number = {1}, pages = {74-88}, pmid = {26931773}, issn = {2041-1014}, support = {R00 DE023584/DE/NIDCR NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 DE012212/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; Bacteria/drug effects/growth & development/immunology ; Biofilms/*drug effects/growth & development ; DNA-Binding Proteins/*immunology/metabolism ; Dental Implants/microbiology ; Disease Models, Animal ; Escherichia coli Proteins/immunology ; Female ; Integration Host Factors/immunology ; Lactic Acid/pharmacology ; Microspheres ; Osteolysis/*immunology/*microbiology/pathology/*therapy ; Peri-Implantitis/immunology/microbiology/pathology/therapy ; Periodontitis/*microbiology ; Polyglycolic Acid/pharmacology ; Polylactic Acid-Polyglycolic Acid Copolymer ; Rabbits ; Rats ; Rats, Sprague-Dawley ; }, abstract = {Periodontal disease exemplifies a chronic and recurrent infection with a necessary biofilm component. Mucosal inflammation is a hallmark response of the host seen in chronic diseases, such as colitis, gingivitis, and periodontitis (and the related disorder peri-implantitis). We have taken advantage of our recently developed rat model of human peri-implantitis that recapitulates osteolysis, the requirement of biofilm formation, and the perpetuation of the bona fide disease state, to test a new therapeutic modality with two novel components. First we used hyperimmune antiserum directed against the DNABII family of proteins, now known to be a critical component of the extracellular matrix of bacterial biofilms. Second we delivered the antiserum as cargo in biodegradable microspheres to the site of the biofilm infection. We demonstrated that delivery of a single dose of anti-DNABII in poly(lactic-co-glycolic acid) (PLGA) microspheres induced significant resolution of experimental peri-implantitis, including marked reduction of inflammation. These data support the continued development of a DNABII protein-targeted therapeutic for peri-implantitis and other chronic inflammatory pathologies of the oral cavity in animals and humans.}, } @article {pmid26931607, year = {2016}, author = {Motlagh, AM and Bhattacharjee, AS and Goel, R}, title = {Biofilm control with natural and genetically-modified phages.}, journal = {World journal of microbiology & biotechnology}, volume = {32}, number = {4}, pages = {67}, pmid = {26931607}, issn = {1573-0972}, mesh = {Bacterial Infections/*therapy ; Bacterial Physiological Phenomena ; Bacteriophages/genetics/*physiology ; Biofilms/*growth & development ; Biofouling/*prevention & control ; Drug Resistance, Bacterial ; Feasibility Studies ; Humans ; Lysogeny ; }, abstract = {Bacteriophages, as the most dominant and diverse entities in the universe, have the potential to be one of the most promising therapeutic agents. The emergence of multidrug-resistant bacteria and the antibiotic crisis in the last few decades have resulted in a renewed interest in phage therapy. Furthermore, bacteriophages, with the capacity to rapidly infect and overcome bacterial resistance, have demonstrated a sustainable approach against bacterial pathogens-particularly in biofilm. Biofilm, as complex microbial communities located at interphases embedded in a matrix of bacterial extracellular polysaccharide substances (EPS), is involved in health issues such as infections associated with the use of biomaterials and chronic infections by multidrug resistant bacteria, as well as industrial issues such as biofilm formation on stainless steel surfaces in food industry and membrane biofouling in water and wastewater treatment processes. In this paper, the most recent studies on the potential of phage therapy using natural and genetically-modified lytic phages and their associated enzymes in fighting biofilm development in various fields including engineering, industry, and medical applications are reviewed. Phage-mediated prevention approaches as an indirect phage therapy strategy are also explored in this review. In addition, the limitations of these approaches and suggestions to overcome these constraints are discussed to enhance the efficiency of phage therapy process. Finally, future perspectives and directions for further research towards a better understanding of phage therapy to control biofilm are recommended.}, } @article {pmid26931384, year = {2016}, author = {Bardiau, M and Caplin, J and Detilleux, J and Graber, H and Moroni, P and Taminiau, B and Mainil, JG}, title = {Existence of two groups of Staphylococcus aureus strains isolated from bovine mastitis based on biofilm formation, intracellular survival, capsular profile and agr-typing.}, journal = {Veterinary microbiology}, volume = {185}, number = {}, pages = {1-6}, doi = {10.1016/j.vetmic.2016.01.003}, pmid = {26931384}, issn = {1873-2542}, mesh = {Animals ; Bacterial Capsules/chemistry ; Bacterial Proteins/genetics ; Bacterial Typing Techniques ; *Biofilms ; Cattle ; Female ; Genome, Bacterial ; Intracellular Space/microbiology ; Mastitis, Bovine/*microbiology ; Species Specificity ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/*classification/genetics/isolation & purification/*physiology ; Trans-Activators/genetics ; Virulence Factors/genetics ; }, abstract = {Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment.}, } @article {pmid26930703, year = {2016}, author = {Montealegre, MC and Singh, KV and Somarajan, SR and Yadav, P and Chang, C and Spencer, R and Sillanpää, J and Ton-That, H and Murray, BE}, title = {Role of the Emp Pilus Subunits of Enterococcus faecium in Biofilm Formation, Adherence to Host Extracellular Matrix Components, and Experimental Infection.}, journal = {Infection and immunity}, volume = {84}, number = {5}, pages = {1491-1500}, pmid = {26930703}, issn = {1098-5522}, support = {R01 AI047923/AI/NIAID NIH HHS/United States ; R01 DE017382/DE/NIDCR NIH HHS/United States ; }, mesh = {Animals ; *Bacterial Adhesion ; Biofilms/*growth & development ; Collagen Type I/metabolism ; Disease Models, Animal ; Endocarditis, Bacterial/microbiology/pathology ; Enterococcus faecium/genetics/*physiology ; Extracellular Matrix/*metabolism ; Female ; Fibrinogen/metabolism ; Fimbriae Proteins/genetics/metabolism ; Fimbriae, Bacterial/*metabolism ; Gene Deletion ; Genetic Complementation Test ; Gram-Positive Bacterial Infections/*microbiology/pathology ; Male ; Mice, Inbred ICR ; Operon ; Organelle Biogenesis ; Rats, Sprague-Dawley ; Urinary Tract Infections/microbiology/pathology ; Virulence Factors/*metabolism ; }, abstract = {Enterococcus faecium is an important cause of hospital-associated infections, including urinary tract infections (UTIs), bacteremia, and infective endocarditis. Pili have been shown to play a role in the pathogenesis of Gram-positive bacteria, including E. faecium We previously demonstrated that a nonpiliated ΔempABC::cat derivative of E. faecium TX82 was attenuated in biofilm formation and in a UTI model. Here, we studied the contributions of the individual pilus subunits EmpA, EmpB, and EmpC to pilus architecture, biofilm formation, adherence to extracellular matrix (ECM) proteins, and infection. We identified EmpA as the tip of the pili and found that deletion of empA reduced biofilm formation to the same level as deletion of the empABC operon, a phenotype that was restored by reconstituting in situ the empA gene. Deletion of empB also caused a reduction in biofilm, while EmpC was found to be dispensable. Significant reductions in adherence to fibrinogen and collagen type I were observed with deletion of empA and empB, while deletion of empC had no adherence defect. Furthermore, we showed that each deletion mutant was significantly attenuated in comparison to the isogenic parental strain, TX82, in a mixed-inoculum UTI model (P < 0.001 to 0.048), that reconstitution of empA restored virulence in the UTI model, and that deletion of empA also resulted in attenuation in an infective endocarditis model (P = 0.0088). Our results indicate that EmpA and EmpB, but not EmpC, contribute to biofilm and adherence to ECM proteins; however, all the Emp pilins are important for E. faecium to cause infection in the urinary tract.}, } @article {pmid26930399, year = {2016}, author = {Shirazi, F and Ferreira, JA and Stevens, DA and Clemons, KV and Kontoyiannis, DP}, title = {Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis.}, journal = {PloS one}, volume = {11}, number = {3}, pages = {e0150155}, pmid = {26930399}, issn = {1932-6203}, mesh = {Apoptosis/*physiology ; Aspergillus fumigatus/*growth & development/metabolism ; Biofilms/*growth & development ; Cystic Fibrosis/*microbiology ; DNA Fragmentation ; Humans ; Mitochondrial Membranes/metabolism ; Pseudomonas aeruginosa/growth & development/*isolation & purification/metabolism ; Reactive Oxygen Species/metabolism ; }, abstract = {Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.}, } @article {pmid26930280, year = {2016}, author = {Sivasankar, C and Maruthupandiyan, S and Balamurugan, K and James, PB and Krishnan, V and Pandian, SK}, title = {A combination of ellagic acid and tetracycline inhibits biofilm formation and the associated virulence of Propionibacterium acnes in vitro and in vivo.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {397-410}, doi = {10.1080/08927014.2016.1148141}, pmid = {26930280}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects/growth & development ; Drug Resistance, Bacterial/drug effects ; Drug Synergism ; Ellagic Acid/*pharmacology ; *Gram-Positive Bacterial Infections/drug therapy/microbiology ; Humans ; Phytochemicals/pharmacology ; *Propionibacterium acnes/drug effects/physiology ; Tetracycline/*pharmacology ; Treatment Outcome ; Virulence/drug effects ; }, abstract = {Propionibacterium acnes is an opportunistic pathogen which has become notorious owing to its ability to form a recalcitrant biofilm and to develop drug resistance. The current study aimed to develop anti-biofilm treatments against clinical isolates of P. acnes under in vitro and in vivo conditions. A combination of ellagic acid and tetracycline (ETC; 250 μg ml(-1) + 0.312 μg ml(-1)) was determined to effectively inhibit biofilm formation by P. acnes (80-91%) without affecting its growth, therefore potentially limiting the possibility of the bacterium attaining resistance. In addition, ETC reduced the production of extracellular polymeric substances (EPS) (20-26%), thereby making P. acnes more susceptible to the human immune system and antibiotics. The anti-biofilm potential of ETC was further substantiated under in vivo conditions using Caenorhabditis elegans. This study reports a novel anti-biofilm combination that could be developed as an ideal therapeutic agent with broad cosmeceutical and pharmaceutical applicability in the era of antibiotic resistance.}, } @article {pmid26930164, year = {2016}, author = {Panwar, R and Pemmaraju, SC and Sharma, AK and Pruthi, V}, title = {Efficacy of ferulic acid encapsulated chitosan nanoparticles against Candida albicans biofilm.}, journal = {Microbial pathogenesis}, volume = {95}, number = {}, pages = {21-31}, doi = {10.1016/j.micpath.2016.02.007}, pmid = {26930164}, issn = {1096-1208}, mesh = {Antifungal Agents/*pharmacology ; Biocompatible Materials/metabolism ; Biofilms/*drug effects ; Candida albicans/*drug effects/metabolism/physiology ; Cell Line ; Cell Survival/drug effects ; Chitosan/*metabolism ; Coumaric Acids/*pharmacology ; Drug Carriers/*metabolism ; Epithelial Cells/drug effects/physiology ; Formazans/analysis ; Humans ; Magnetic Resonance Spectroscopy ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Nanoparticles/chemistry/*metabolism/toxicity/ultrastructure ; Spectroscopy, Fourier Transform Infrared ; Staining and Labeling ; }, abstract = {Candida albicans, an opportunistic fungal pathogen is a major causative agent of superficial to systemic life-threating biofilm infections on indwelling medical devices. These biofilms acts as double edge swords owing to their resistance towards antibiotics and immunological barriers. To overcome this threat ferulic acid encapsulated chitosan nanoparticles (FA-CSNPs) were formulated to assess its efficacy as an antibiofilm agent against C. albicans. These FA-CSNPs were synthesized using ionotropic gelation method and observed through field emission scanning electron microscopy (FESEM) and fluorescent microscopy. Assessment of successful encapsulation and stability of ferulic acid into chitosan nanoparticles was made using Fourier transform infrared spectrum (FTIR), (1)H NMR and thermal analyses. Synthesized FA-CSNPs, were found to be cytocompatible, when tested using Human Embryonic Kidney (HEK-293) cell lines. XTT assay revealed that FA-CSNPs reduced the cell metabolic activity of C. albicans upto 22.5% as compared to native ferulic acid (63%) and unloaded CSNPs (88%) after 24 h incubation. Disruption of C. albicans biofilm architecture was visualized by FESEM. Results highlighted the potential of FA-CSNPs to be used as an effective alternative to the conventional antifungal therapeutics.}, } @article {pmid26930141, year = {2016}, author = {Vadekeetil, A and Saini, H and Chhibber, S and Harjai, K}, title = {Exploiting the antivirulence efficacy of an ajoene-ciprofloxacin combination against Pseudomonas aeruginosa biofilm associated murine acute pyelonephritis.}, journal = {Biofouling}, volume = {32}, number = {4}, pages = {371-382}, doi = {10.1080/08927014.2015.1137289}, pmid = {26930141}, issn = {1029-2454}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Load/drug effects ; *Biofilms/drug effects/growth & development ; Ciprofloxacin/*pharmacology ; Disease Models, Animal ; Disulfides/*pharmacology ; Drug Synergism ; Glutathione Reductase/antagonists & inhibitors ; Kidney/microbiology/pathology ; Mice ; Microbial Sensitivity Tests/methods ; *Pseudomonas aeruginosa/drug effects/physiology ; *Pyelonephritis/drug therapy/microbiology ; Sulfoxides ; Treatment Outcome ; }, abstract = {The study investigated the in vitro, ex vivo and in vivo efficacy of ajoene and ciprofloxacin (CIP) alone and in combination against Pseudomonas aeruginosa biofilms and biofilm-associated murine acute pyelonephritis. The ajoene-CIP combination exhibited significant greater (p < 0.05) antimotility and biofilm inhibitory effects than those obtained when they were applied individually. The combined action of the agents resulted in a significant increase in serum sensitivity and phagocytic uptake and killing of P. aeruginosa (p < 0.001) compared to the untreated control. Mice groups treated with an ajoene (25 mg kg(-1)) and CIP (30 mg kg(-1) or 15 mg kg(-1)) combination showed a significantly (p < 0.001) reduced bacterial load in the kidney and bladder as compared to that of infected controls and mice treated with solo agents on the fifth day post-infection. The decreased levels of biomarkers and photomicrographs of the kidney tissue of the treated mice showed a reduced severity of damage. Hence, the study highlights the antivirulent and therapeutic efficacy of the ajoene-CIP combination at the minimal dosage of CIP.}, } @article {pmid26929093, year = {2016}, author = {Chanyi, RM and Koval, SF and Brooke, JS}, title = {Stenotrophomonas maltophilia biofilm reduction by Bdellovibrio exovorus.}, journal = {Environmental microbiology reports}, volume = {8}, number = {3}, pages = {343-351}, doi = {10.1111/1758-2229.12384}, pmid = {26929093}, issn = {1758-2229}, mesh = {Anti-Bacterial Agents/pharmacology ; *Antibiosis ; Bdellovibrio/*growth & development/isolation & purification ; Biofilms/*growth & development ; Ciprofloxacin/pharmacology ; Environmental Microbiology ; Gram-Negative Bacterial Infections/microbiology ; Humans ; Kanamycin/pharmacology ; Sewage/microbiology ; Stenotrophomonas maltophilia/drug effects/growth & development/isolation & purification/*physiology ; }, abstract = {Stenotrophomonas maltophilia, a bacterium ubiquitous in the environment, is also an opportunistic, multidrug-resistant human pathogen that colonizes tissues and medical devices via biofilm formation. We investigated the ability of an isolate from sewage of the bacterial predator Bdellovibrio exovorus to disrupt preformed biofilms of 18 strains of S. maltophilia isolated from patients, hospital sink drains and water fountain drains. B. exovorus FFRS-5 preyed on all S. maltophilia strains in liquid co-cultures and was able to significantly disrupt the biofilms of 15 of the S. maltophilia strains tested, decreasing as much as 76.7% of the biofilm mass. The addition of ciprofloxacin and kanamycin in general reduced S. maltophilia biofilms but less than that of B. exovorus alone. Furthermore, when antibiotics and B. exovorus were used together, B. exovorus was still effective in the presence of ciprofloxacin whereas the addition of kanamycin reduced the effectiveness of B. exovorus. Overall, B. exovorus was able to decrease the mass of preformed biofilms of S. maltophilia in the presence of clinically relevant antibiotics demonstrating that the predator may prove to be a beneficial tool to reduce S. maltophilia environmental or clinically associated biofilms.}, } @article {pmid26927542, year = {2016}, author = {Bhoopalan, SV and Piekarowicz, A and Lenz, JD and Dillard, JP and Stein, DC}, title = {nagZ Triggers Gonococcal Biofilm Disassembly.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {22372}, pmid = {26927542}, issn = {2045-2322}, support = {AI097157/AI/NIAID NIH HHS/United States ; R01 AI068888/AI/NIAID NIH HHS/United States ; AI068888/AI/NIAID NIH HHS/United States ; AI048703/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; F32 AI115911/AI/NIAID NIH HHS/United States ; R01 AI097157/AI/NIAID NIH HHS/United States ; }, mesh = {Acetylglucosaminidase/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Cervix Uteri/*microbiology ; Female ; Gonorrhea/microbiology/*pathology ; Humans ; *Neisseria gonorrhoeae/genetics/pathogenicity/physiology ; }, abstract = {Bacterial-bacterial interactions play a critical role in promoting biofilm formation. Here we show that NagZ, a protein associated with peptidoglycan recycling, has moonlighting activity that allows it to modulate biofilm accumulation by Neisseria gonorrhoeae. We characterize the biochemical properties of NagZ and demonstrate its ability to function as a dispersing agent for biofilms formed on abiotic surfaces. We extend these observations to cell culture and tissue explant models and show that in nagZ mutants, the biofilms formed in cell culture and on human tissues contain significantly more biomass than those formed by a wild-type strain. Our results demonstrate that an enzyme thought to be restricted to peptidoglycan recycling is able to disperse preformed biofilms.}, } @article {pmid26926643, year = {2016}, author = {Pantel, A and Dunyach-Remy, C and Ngba Essebe, C and Mesureur, J and Sotto, A and Pagès, JM and Nicolas-Chanoine, MH and Lavigne, JP}, title = {Modulation of Membrane Influx and Efflux in Escherichia coli Sequence Type 131 Has an Impact on Bacterial Motility, Biofilm Formation, and Virulence in a Caenorhabditis elegans Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {5}, pages = {2901-2911}, pmid = {26926643}, issn = {1098-6596}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Biofilms/drug effects ; Biological Transport/physiology ; Caenorhabditis elegans/microbiology ; Cefoxitin/pharmacology ; Chloramphenicol/pharmacology ; Ertapenem ; Escherichia coli/drug effects/genetics/*metabolism ; Mutation ; Virulence ; beta-Lactams/pharmacology ; }, abstract = {Energy-dependent efflux overexpression and altered outer membrane permeability (influx) can promote multidrug resistance (MDR). The present study clarifies the regulatory pathways that control membrane permeability in the pandemic clone Escherichia coli sequence type 131 (ST131) and evaluates the impact of efflux and influx modulations on biofilm formation, motility, and virulence in the Caenorhabditis elegans model. Mutants of two uropathogenic E. coli (UPEC) strains, MECB5 (ST131; H30-Rx) and CFT073 (ST73), as well as a fecal strain, S250 (ST131; H22), were in vitro selected using continuous subculture in subinhibitory concentrations of ertapenem (ETP), chloramphenicol (CMP), and cefoxitin (FOX). Mutations in genes known to control permeability were shown for the two UPEC strains: MECB5-FOX (deletion of 127 bp in marR; deletion of 1 bp and insertion of an IS1 element in acrR) and CFT073-CMP (a 1-bp deletion causing a premature stop in marR). We also demonstrated that efflux phenotypes in the mutants selected with CMP and FOX were related to the AcrAB-TolC pump, but also to other efflux systems. Alteration of membrane permeability, caused by underexpression of the two major porins, OmpF and OmpC, was shown in MECB5-ETP and mutants selected with FOX. Lastly, our findings suggest that efflux pump-overproducing isolates (CMP mutants) pose a serious threat in terms of virulence (significant reduction in worm median survival) and host colonization. Lack of porins (ETP and FOX mutants) led to a high level of antibiotic resistance in an H30-Rx subclone. Nevertheless, this adaptation created a physiological disadvantage (decreased motility and ability to form biofilm) associated with a low potential for virulence.}, } @article {pmid26926200, year = {2016}, author = {Deng, L and Guo, W and Ngo, HH and Zhang, X and Wang, XC and Zhang, Q and Chen, R}, title = {New functional biocarriers for enhancing the performance of a hybrid moving bed biofilm reactor-membrane bioreactor system.}, journal = {Bioresource technology}, volume = {208}, number = {}, pages = {87-93}, doi = {10.1016/j.biortech.2016.02.057}, pmid = {26926200}, issn = {1873-2976}, mesh = {Animals ; Biofilms ; Biopolymers ; *Bioreactors ; Equipment Design ; Membranes, Artificial ; Nitrogen/isolation & purification ; Phosphorus/isolation & purification ; Plastics ; Sewage ; Waste Disposal, Fluid/*instrumentation/*methods ; }, abstract = {In this study, new sponge modified plastic carriers for moving bed biofilm reactor (MBBR) was developed. The performance and membrane fouling behavior of a hybrid MBBR-membrane bioreactor (MBBR-MBR) system were also evaluated. Comparing to the MBBR with plastic carriers (MBBR), the MBBR with sponge modified biocarriers (S-MBBR) showed better effluent quality and enhanced nutrient removal at HRTs of 12h and 6h. Regarding fouling issue of the hybrid systems, soluble microbial products (SMP) of the MBR unit greatly influenced membrane fouling. The sponge modified biocarriers could lower the levels of SMP in mixed liquor and extracellular polymeric substances in activated sludge, thereby mitigating cake layer and pore blocking resistances of the membrane. The reduced SMP and biopolymer clusters in membrane cake layer were also observed. The results demonstrated that the sponge modified biocarriers were capable of improving overall MBBR performance and substantially alleviated membrane fouling of the subsequent MBR unit.}, } @article {pmid26926191, year = {2016}, author = {Li, Y and Du, Y and Ye, J and Wang, B and Liu, Y}, title = {[Effect of extracellular DNA on the formation of Streptococcus mutans biofilm under sucrose environment].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {51}, number = {2}, pages = {81-86}, doi = {10.3760/cma.j.issn.1002-0098.2016.02.004}, pmid = {26926191}, issn = {1002-0098}, mesh = {Bacterial Adhesion/drug effects ; Biofilms/*growth & development ; DNA/*physiology ; Deoxyribonuclease I/pharmacology ; Microscopy, Confocal ; Streptococcus mutans/*physiology ; *Sucrose ; *Sweetening Agents ; Temperature ; }, abstract = {OBJECTIVE: To study the effect of extracellular DNA(eDNA) on the formation of Streptococcus mutans(Sm) biofilms during different growth periods in sucrose environment.

METHODS: Sm biofilms were established on smooth glass surfaces under the environment of 1% sucrose and cultured in the condition of 37 ℃, 5% O2, 85% N2 and 10% CO2. Samples were randomly divided into four groups based on fourculture time(6,12, 24 and 48 h), respectively. Each group was further divided into two subgroups: control group(without deoxyribonuclease Ⅰ[DNaseⅠ] treatment) and test group(with DNaseⅠtreatment). DNaseⅠ was added 1 h advance in the treatment group to a final concentration of 100 U/ml. Each sample was stained with mixed SYTO-9/PI fluorescent dye. Confocal laser scanning microscopy was used for biofilm observation and scanning. The total biomass, the thickness and the volume of red fluorescence of each biofilm sample were measured following three-dimensional reconstruction using the softwear of Imaris 7.2.3.

RESULTS: Under the environment of 1% sucrose, the Sm bacterial adhesion and distribution density increased over time, the quantity of eDNA and membrane-damaged bacteria which were indicated by red fluorescence also increased within 24 h but dropped later. The biofilm biomasses of Sm biofilm in 6, 12, 24 and 48 h DNaseⅠ treatment group reduced significantly(P<0.05) compared to those in the corresponding control groups by 81.3%, 85.0%, 90.1% and 12.4%, respectively. The biofilm thicknesses in each DNase Ⅰ treatment group (except 6 h group) also reduced significantly(P<0.05) compared to those in the corresponding control group by 34.4%, 45.6% and 23.6%, respectively. The quantities of eDNA and membrane-damaged bacteria reduced in each treatment group except 48 h group compared to that in the corresponding control group.

CONCLUSIONS: Under the environment of 1% sucrose, eDNA plays an important role in promoting the formation of Sm biofilm.}, } @article {pmid26926069, year = {2016}, author = {Schweitzer, MH and Moyer, AE and Zheng, W}, title = {Testing the Hypothesis of Biofilm as a Source for Soft Tissue and Cell-Like Structures Preserved in Dinosaur Bone.}, journal = {PloS one}, volume = {11}, number = {2}, pages = {e0150238}, pmid = {26926069}, issn = {1932-6203}, mesh = {Animals ; Bacillus cereus/physiology ; *Biofilms ; Blood Vessels/microbiology ; Bone and Bones/*cytology/*microbiology/physiology ; Calcification, Physiologic ; Cattle ; *Dinosaurs ; Fossils ; Staphylococcus epidermidis/physiology ; }, abstract = {Recovery of still-soft tissue structures, including blood vessels and osteocytes, from dinosaur bone after demineralization was reported in 2005 and in subsequent publications. Despite multiple lines of evidence supporting an endogenous source, it was proposed that these structures arose from contamination from biofilm-forming organisms. To test the hypothesis that soft tissue structures result from microbial invasion of the fossil bone, we used two different biofilm-forming microorganisms to inoculate modern bone fragments from which organic components had been removed. We show fundamental morphological, chemical and textural differences between the resultant biofilm structures and those derived from dinosaur bone. The data do not support the hypothesis that biofilm-forming microorganisms are the source of these structures.}, } @article {pmid26925869, year = {2016}, author = {Morgenstern, M and Post, V and Erichsen, C and Hungerer, S and Bühren, V and Militz, M and Richards, RG and Moriarty, TF}, title = {Biofilm formation increases treatment failure in Staphylococcus epidermidis device-related osteomyelitis of the lower extremity in human patients.}, journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society}, volume = {34}, number = {11}, pages = {1905-1913}, doi = {10.1002/jor.23218}, pmid = {26925869}, issn = {1554-527X}, mesh = {Adult ; Aged ; Anti-Infective Agents/therapeutic use ; *Biofilms ; Female ; Humans ; Male ; *Methicillin Resistance ; Middle Aged ; Phenotype ; Prospective Studies ; Prosthesis-Related Infections/drug therapy/*microbiology ; Recurrence ; Staphylococcus epidermidis/*pathogenicity/physiology ; Treatment Failure ; }, abstract = {UNLABELLED: The ability to form biofilm on the surface of implanted devices is often considered the most critical virulence factor possessed by Staphylococcus epidermidis in its role as an opportunistic pathogen in orthopaedic device-related infection (ODRI). Despite this recognition, there is a lack of clinical evidence linking outcome with biofilm forming ability for S. epidermidis ODRIs. We prospectively collected S. epidermidis isolates cultured from patients presenting with ODRI. Antibiotic resistance patterns and biofilm-forming ability was assessed. Patient information was collected and treatment outcome measures were determined after a mean follow-up period of 26 months. The primary outcome measure was cure at follow-up. Univariate logistic regression models were used to determine the influence of biofilm formation and antibiotic resistance on treatment outcome. A total of 124 patients were included in the study, a majority of whom (n = 90) involved infections of the lower extremity. A clear trend emerged in the lower extremity cohort whereby cure rates decreased as the biofilm-forming ability of the isolates increased (84% cure rate for infections caused by non-biofilm formers, 76% cure rate for weak biofilm-formers, and 60% cure rate for the most marked biofilm formers, p = 0.076). Antibiotic resistance did not influence treatment cure rate. Chronic immunosuppression was associated with a statistically significant decrease in cure rate (p = 0.044).

CLINICAL SIGNIFICANCE: The trend of increasing biofilm-forming ability resulting in lower cure rates for S. epidermidis ODRI indicates biofilm-forming ability of infecting pathogens does influence treatment outcome of infections of the lower extremity. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1905-1913, 2016.}, } @article {pmid26923699, year = {2016}, author = {Zaheer, Z and Khan, FA and Sangshetti, JN and Patil, RH and Lohar, KS}, title = {Novel amalgamation of phthalazine-quinolines as biofilm inhibitors: One-pot synthesis, biological evaluation and in silico ADME prediction with favorable metabolic fate.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {26}, number = {7}, pages = {1696-1703}, doi = {10.1016/j.bmcl.2016.02.057}, pmid = {26923699}, issn = {1464-3405}, mesh = {Anti-Infective Agents/chemical synthesis/*chemistry/*pharmacology ; Biofilms/drug effects ; Candida albicans/drug effects/physiology ; Candidiasis/drug therapy ; Computer Simulation ; Humans ; Phthalazines/chemical synthesis/*chemistry/*pharmacology ; Pseudomonas Infections/drug therapy ; Pseudomonas aeruginosa/drug effects/physiology ; Quinolines/chemical synthesis/*chemistry/*pharmacology ; }, abstract = {A facile and highly efficient one-pot synthesis of phthalazine-quinoline derivatives is reported via four component reaction of phthalic anhydride, hydrazine hydrate, 5,5-dimethyl 1,3 cyclohexanedione and various quinoline aldehydes using PrxCoFe2-xO4 (x=0.1) nanoparticles as a catalyst. The synthesized compounds have been evaluated for anti-biofilm activity against Pseudomonas aeruginosa and Candida albicans. The compounds 12a (IC50=30.0μM) and 12f (IC50=34.5μM) had shown promising anti-biofilm activity against P. aeruginosa and C. albicans, respectively, when compared with standards without affecting the growth of cells (and thus behave as anti-quorum sensing agents). Compounds 12a (MIC=45.0μg/mL) and 12f (MIC=57.5μg/mL) showed significant potent antimicrobial activity against P. aeruginosa and C. albicans, respectively. Thus, the active derivatives were not only potent biofilm inhibitors but also efficient antimicrobial agents. In silico ADME and metabolic site prediction studies were also held out to set an effective lead candidate for the future antimicrobial drug discovery initiatives.}, } @article {pmid26923144, year = {2016}, author = {Stiefel, P and Rosenberg, U and Schneider, J and Mauerhofer, S and Maniura-Weber, K and Ren, Q}, title = {Is biofilm removal properly assessed? Comparison of different quantification methods in a 96-well plate system.}, journal = {Applied microbiology and biotechnology}, volume = {100}, number = {9}, pages = {4135-4145}, pmid = {26923144}, issn = {1432-0614}, mesh = {Bacteria/*drug effects ; Bacterial Load ; Bacteriological Techniques/*methods ; Biofilms/*drug effects ; Biomass ; Disinfection/*methods ; Microbial Viability/drug effects ; Reproducibility of Results ; }, abstract = {Various methods have been reported to quantify total biofilm or different components of biofilm; however, these methods are often confusedly used, leading to discrepancies and misleading results. In this study, different methods for quantification of biofilm, including those for total biomass, total amount of bacterial cells, viable cell number, and amount of extracellular polymeric substances, were systematically compared in microtiter plates. To evaluate which method is suitable for assessment of biofilm removal and for bacterial killing, biofilm samples were treated with various cleaners possessing removing and/or killing capacities. It was found that most of the methods tested in this study in general exhibited high reproducibility and repeatability. Crystal Violet staining was a simple but reliable method for total biomass quantification. Total bacteria cell numbers could be reliably quantified by the fluorescent DNA-binding dye Acridine Orange. Viable cells could be quantified by either an ATP-based assay or a proliferation assay. Both of these viability methods showed a broad detection range and led to precise measurement. For quantification of proteins in the biofilm, staining with fluorescein isothiocyanate was most suitable. Furthermore, it was revealed that a combination of different methods is required to determine if a cleaner kills or removes biofilm.}, } @article {pmid26921710, year = {2016}, author = {Li, X and Sun, S and Badgley, BD and Sung, S and Zhang, H and He, Z}, title = {Nitrogen removal by granular nitritation-anammox in an upflow membrane-aerated biofilm reactor.}, journal = {Water research}, volume = {94}, number = {}, pages = {23-31}, doi = {10.1016/j.watres.2016.02.031}, pmid = {26921710}, issn = {1879-2448}, mesh = {Ammonium Compounds/*chemistry ; Bacteria/classification ; Biofilms ; *Bioreactors/microbiology ; DNA, Bacterial/isolation & purification ; Membranes, Artificial ; Nitrates/analysis ; Nitrogen/*chemistry ; Wastewater/*chemistry ; Water Purification/*methods ; }, abstract = {The nitritation-anammox process has been a promising nitrogen removal technology towards sustainable wastewater treatment, but its application in treating domestic wastewater with relatively low ammonium concentrations (mainstream) remains a great challenge. In this study, an innovative lab-scale upflow membrane-aerated biofilm reactor (UMABR) was employed to treat a synthetic wastewater containing 70 mg N L(-1) ammonium. With a DO level at 0.6 ± 0.1 mg O2 L(-1) and HRT of 32 h, the effluent ammonium concentration was 4.8 ± 2.0 mg N L(-1). Increasing the nitrogen loading rate from 52.4 to 104.8 g N m(-3) d(-1) with stepwise decreasing HRT from 32 to 16 h resulted in an average TN removal efficiency of 81% without nitrite accumulation. The average observed NO3(-)-N (residue)/NH4(+)-N (consumed) ratio of 8% was below the "theoretical ratio" of 13% and further reduction of nitrate residue needs to be addressed. Fluorescence in situ hybridization (FISH) and high-throughput sequencing analyses showed the coexistence of anammox bacteria and ammonium-oxidizing bacteria (AOB) in both biofilm and granular samples. Anammox bacteria accounted for up to 63.3% of the microbial community of the granules, with Candidatus Jettenia being the distinctly dominant anammox genus. In contrast, the biofilm contained abundant Nitrosomonadaceae (AOB, 33.1%). In addition, the brown-yellow granules exhibited a more balanced community structure with anammox bacteria and AOB accounting for 33.7% and 18.2%, respectively, which may contribute to the long-term operation of single-stage nitritation-anammox process. These results demonstrate that the nitritation-anammox UMABR could potentially be used for nitrogen removal from mainstream in some specific regions with relatively warm temperature.}, } @article {pmid26919939, year = {2016}, author = {Sulistyani, H and Fujita, M and Miyakawa, H and Nakazawa, F}, title = {Effect of roselle calyx extract on in vitro viability and biofilm formation ability of oral pathogenic bacteria.}, journal = {Asian Pacific journal of tropical medicine}, volume = {9}, number = {2}, pages = {119-124}, doi = {10.1016/j.apjtm.2016.01.020}, pmid = {26919939}, issn = {2352-4146}, abstract = {OBJECTIVE: To investigate the effect of the roselle calyx extract (RCE) (Hibiscus sabdariffa L.) on the in vitro viability and biofilm formation ability of oral pathogenic bacteria.

METHODS: RCE was prepared by soaking roselle calyx powder with ethyl alcohol for 24 h at room temperature. After centrifugation, the extract was lyophilized. Then, the extract was dissolved in phosphate-buffered saline, the pH was adjusted, and the extract was aseptically filtered. We used Streptococcus mutans, Streptococcus sanguinis, Lactobacillus casei, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia in this study. The antibacterial activity of the RCE was determined by treating the cells of these bacteria with the extract for 10 or 20 min at room temperature. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration was determined using the microdilution method, and the effect of the RCE on the ability to form biofilm was determined using a polystyrene micro plate assay. In addition, we used the WST-1 assay to determine the cytotoxicity of the RCE on HGF, Ca9-22 and KB cells.

RESULTS: The RCE had antibacterial activity against oral bacteria used in this study. In particular, most significant antibacterial activity was observed against Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis. The MIC and minimum bactericidal concentration were 7.2 mg/mL-28.8 mg/mL and 14.4 to >57.6 mg/mL. The RCE had an inhibitory effect on biofilm formation at the MIC and sub-MIC levels. In addition, the RCE had low cytotoxic effects on HGF, Ca9-22 and KB cells.

CONCLUSIONS: Thus, our results indicate that the RCE may be used for preventing oral diseases.}, } @article {pmid26919816, year = {2016}, author = {Grounta, A and Doulgeraki, AI and Nychas, GJ and Panagou, EZ}, title = {Biofilm formation on Conservolea natural black olives during single and combined inoculation with a functional Lactobacillus pentosus starter culture.}, journal = {Food microbiology}, volume = {56}, number = {}, pages = {35-44}, doi = {10.1016/j.fm.2015.12.002}, pmid = {26919816}, issn = {1095-9998}, mesh = {Biofilms/*growth & development ; Fermentation ; *Food Microbiology ; Hydrogen-Ion Concentration ; Lactic Acid/metabolism ; Lactobacillus/*physiology ; Olea/*microbiology ; Probiotics/metabolism ; Salts/chemistry ; }, abstract = {The potential of biofilm formation of multifunctional starters Lactobacillus pentosus B281 and Pichia membranifaciens M3A during inoculated fermentation of Conservolea natural black olives according to Greek-style processing was investigated. Olives were directly brined in 8% (w/v) NaCl following three fermentation procedures namely, i) spontaneous fermentation, ii) inoculated fermentation with L. pentosus B281, and iii) co-inoculated fermentation with L. pentosus B281 and P. membranifaciens M3A. Lactic acid bacteria (LAB) and yeasts were monitored on olives by plate counting for a period of 153 days, whereas the survival of the inoculated strains was confirmed by Pulsed Field Gel Electrophoresis (PFGE) and Restriction Fragment Length Polymorphism (RFLP) analysis. Inoculated fermentation with L. pentosus B281 with/without the presence of the yeast resulted in higher acidification of the brine compared to the spontaneous process where no indigenous LAB could be enumerated. The population of LAB on olives ranged between 5.5 and 6.5 log CFU/g and it was maintained at higher levels compared to yeasts (3.5-4.5 log CFU/g) throughout the process. PFGE analysis revealed that L. pentosus B281 could successfully colonize the surface of black olives presenting high recovery rate (100%) at the end of fermentation in contrast to P. membranifaciens M3A that was successfully recovered (42%) only after 72 days of the process. The obtained results provide interesting perspectives for the production of natural black olives with functional properties.}, } @article {pmid26916812, year = {2016}, author = {Almeida, AA and Crispim, Bdo A and Grisolia, AB and Svidzinski, TI and Ortolani, LG and Oliveira, KM}, title = {Genotype, antifungal susceptibility, and biofilm formation of Trichosporon asahii isolated from the urine of hospitalized patients.}, journal = {Revista Argentina de microbiologia}, volume = {48}, number = {1}, pages = {62-66}, doi = {10.1016/j.ram.2015.11.005}, pmid = {26916812}, issn = {0325-7541}, mesh = {Antifungal Agents/*pharmacology ; *Biofilms ; Cross Infection/microbiology ; Genotype ; Hospitalization ; Humans ; Microbial Sensitivity Tests ; Trichosporon/*drug effects/genetics/isolation & purification/*physiology ; Urinary Tract Infections/microbiology ; Urine/microbiology ; }, abstract = {In this study, the culture analysis of urine samples from patients hospitalized in the Central-West region of Brazil was performed, and the isolated microorganisms were phylogenetically identified as Trichosporon asahii. Maximum parsimony analysis of the IGS1 sequences revealed three novel genotypes that have not been described. The minimum inhibitory concentrations of the nine isolates identified were in the range of 0.06-1 μg/ml for amphotericin B, 0.25-4 μg/ml for fluconazole, and 0.03-0.06 μg/ml for itraconazole. Approximately 6/9 of the T. asahii isolates could form biofilms on the surface of polystyrene microplates. This study reports that the microorganisms isolated here as T. asahii are agents of nosocomial urinary tract infections. Furthermore, the IGS1 region can be considered a new epidemiological tool for genotyping T. asahii isolates. The least common genotypes reported in this study can be related to local epidemiological trends.}, } @article {pmid26913481, year = {2016}, author = {Parker, JK and Chen, H and McCarty, SE and Liu, LY and De La Fuente, L}, title = {Calcium transcriptionally regulates the biofilm machinery of Xylella fastidiosa to promote continued biofilm development in batch cultures.}, journal = {Environmental microbiology}, volume = {18}, number = {5}, pages = {1620-1634}, doi = {10.1111/1462-2920.13242}, pmid = {26913481}, issn = {1462-2920}, mesh = {Biofilms/*growth & development ; Bioreactors ; Calcium/administration & dosage/*metabolism/pharmacology ; Xylella/*physiology ; }, abstract = {The functions of calcium (Ca) in bacteria are less characterized than in eukaryotes, where its role has been studied extensively. The plant-pathogenic bacterium Xylella fastidiosa has several virulence features that are enhanced by increased Ca concentrations, including biofilm formation. However, the specific mechanisms driving modulation of this feature are unclear. Characterization of biofilm formation over time showed that 4 mM Ca supplementation produced denser biofilms that were still developing at 96 h, while biofilm in non-supplemented media had reached the dispersal stage by 72 h. To identify changes in global gene expression in X. fastidiosa grown in supplemental Ca, RNA-Seq of batch culture biofilm cells was conducted at three 24-h time intervals. Results indicate that a variety of genes are differentially expressed in response to Ca, including genes related to attachment, motility, exopolysaccharide synthesis, biofilm formation, peptidoglycan synthesis, regulatory functions, iron homeostasis, and phages. Collectively, results demonstrate that Ca supplementation induces a transcriptional response that promotes continued biofilm development, while biofilm cells in nonsupplemented media are driven towards dispersion of cells from the biofilm structure. These results have important implications for disease progression in planta, where xylem sap is the source of Ca and other nutrients for X. fastidiosa.}, } @article {pmid26912180, year = {2016}, author = {Sharma, A and Gupta, P and Kumar, R and Bhardwaj, A}, title = {dPABBs: A Novel in silico Approach for Predicting and Designing Anti-biofilm Peptides.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {21839}, pmid = {26912180}, issn = {2045-2322}, mesh = {Antimicrobial Cationic Peptides/*chemistry/pharmacology ; Area Under Curve ; Biofilms/drug effects ; Databases, Factual ; *Drug Design ; Internet ; Quorum Sensing/drug effects ; ROC Curve ; Support Vector Machine ; *User-Computer Interface ; }, abstract = {Increasingly, biofilms are being recognised for their causative role in persistent infections (like cystic fibrosis, otitis media, diabetic foot ulcers) and nosocomial diseases (biofilm-infected vascular catheters, implants and prosthetics). Given the clinical relevance of biofilms and their recalcitrance to conventional antibiotics, it is imperative that alternative therapeutics are proactively sought. We have developed dPABBs, a web server that facilitates the prediction and design of anti-biofilm peptides. The six SVM and Weka models implemented on dPABBs were observed to identify anti-biofilm peptides on the basis of their whole amino acid composition, selected residue features and the positional preference of the residues (maximum accuracy, sensitivity, specificity and MCC of 95.24%, 92.50%, 97.73% and 0.91, respectively, on the training datasets). On the N-terminus, it was seen that either of the cationic polar residues, R and K, is present at all five positions in case of the anti-biofilm peptides, whereas in the QS peptides, the uncharged polar residue S is preponderant at the first (also anionic polar residues D, E), third and fifth positions. Positive predictions were also obtained for 29 FDA-approved peptide drugs and ten antimicrobial peptides in clinical development, indicating at their possible repurposing for anti-biofilm therapy. dPABBs is freely accessible on: http://ab-openlab.csir.res.in/abp/antibiofilm/.}, } @article {pmid26910444, year = {2016}, author = {Martini, R and Hörner, R and Rampelotto, RF and Garzon, LR and Nunes, MS and Teixeira, MD and Graichen, DÂ}, title = {INVESTIGATION OF BIOFILM FORMATION IN COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM PLATELET CONCENTRATE BAGS.}, journal = {Revista do Instituto de Medicina Tropical de Sao Paulo}, volume = {58}, number = {}, pages = {1}, pmid = {26910444}, issn = {1678-9946}, mesh = {Agar ; Biofilms/*growth & development ; Blood Platelets/*microbiology ; *Coagulase ; Humans ; Polymerase Chain Reaction ; Staphylococcal Infections/*microbiology ; Staphylococcus/classification/*isolation & purification/physiology ; }, abstract = {Platelet Concentrates (PCs) are the blood components with the highest rate of bacterial contamination, and coagulase-negative staphylococci (CoNS) are the most frequently isolated contaminants. This study investigated the biofilm formation of 16 contaminated units out of 691 PCs tested by phenotypic and genotypic methods. Adhesion in Borosilicate Tube (ABT) and Congo Red Agar (CRA) tests were used to assess the presence of biofilm. The presence of icaADC genes was assessed by means of the Polymerase Chain Reaction (PCR) technique. With Vitek(r)2, Staphylococcus haemolyticus was considered the most prevalent CoNS (31.25%). The CRA characterized 43.8% as probable biofilm producers, and for the ABT test, 37.5%. The icaADC genes were identified in seven samples by the PCR. The ABT technique showed 85.7% sensitivity and 100% specificity when compared to the reference method (PCR), and presented strong agreement (k = 0.8). This study shows that species identified as PCs contaminants are considered inhabitants of the normal skin flora and they might become important pathogens. The results also lead to the recommendation of ABT use in laboratory routine for detecting biofilm in CoNS contaminants of PCs.}, } @article {pmid26909385, year = {2016}, author = {Cochis, A and Azzimonti, B and Sorrentino, R and Della Valle, C and De Giglio, E and Bloise, N and Visai, L and Bruni, G and Cometa, S and Pezzoli, D and Candiani, G and Rimondini, L and Chiesa, R}, title = {Data in support of Gallium (Ga(3+)) antibacterial activities to counteract E. coli and S. epidermidis biofilm formation onto pro-osteointegrative titanium surfaces.}, journal = {Data in brief}, volume = {6}, number = {}, pages = {758-762}, pmid = {26909385}, issn = {2352-3409}, abstract = {This paper contains original data supporting the antibacterial activities of Gallium (Ga(3+))-doped pro-osteointegrative titanium alloys, obtained via Anodic Spark Deposition (ASD), as described in "The effect of silver or gallium doped titanium against the multidrug resistant Acinetobacter baumannii" (Cochis et al. 2016) [1]. In this article we included an indirect cytocompatibility evaluation towards Saos2 human osteoblasts and extended the microbial evaluation of the Ga(3+) enriched titanium surfaces against the biofilm former Escherichia coli and Staphylococcus epidermidis strains. Cell viability was assayed by the Alamar Blue test, while bacterial viability was evaluated by the metabolic colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Finally biofilm morphology was analyzed by Scanning Electron Microscopy (SEM). Data regarding Ga(3+) activity were compared to Silver.}, } @article {pmid26909074, year = {2016}, author = {Brandwein, M and Al-Quntar, A and Goldberg, H and Mosheyev, G and Goffer, M and Marin-Iniesta, F and López-Gómez, A and Steinberg, D}, title = {Mitigation of Biofilm Formation on Corrugated Cardboard Fresh Produce Packaging Surfaces Using a Novel Thiazolidinedione Derivative Integrated in Acrylic Emulsion Polymers.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {159}, pmid = {26909074}, issn = {1664-302X}, abstract = {Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analog cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry (EDS) analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed.}, } @article {pmid26907201, year = {2016}, author = {Sefid, F and Rasooli, I and Payandeh, Z}, title = {Homology modeling of a Camelid antibody fragment against a conserved region of Acinetobacter baumannii biofilm associated protein (Bap).}, journal = {Journal of theoretical biology}, volume = {397}, number = {}, pages = {43-51}, doi = {10.1016/j.jtbi.2016.02.015}, pmid = {26907201}, issn = {1095-8541}, mesh = {Acinetobacter baumannii/genetics/*immunology ; Animals ; Bacterial Proteins/chemistry/genetics/*immunology ; Base Sequence ; Binding Sites, Antibody/genetics/immunology ; Camelids, New World/genetics/*immunology ; Ligands ; Models, Molecular ; Protein Binding/immunology ; Protein Domains ; Sequence Homology, Amino Acid ; Single-Domain Antibodies/chemistry/genetics/*immunology ; }, abstract = {BACKGROUND: VHH or the single-domain antibodies (sdAb), are studied for therapeutic applications in cancers, infections and other diseases. In our previous study, we expressed and produced a soluble VHH against a conserved region of Acinetobacter baumannii biofilm associated protein (Bap). The present study was undertaken to predict the 2D and 3D structure of the receptor and ligand as well as residues involved in their interactions.

METHODS AND FINDINGS: Apart from ab initio, other rational methods such as homology modeling and threading were invoked to achieve the 3D structures. For homology modeling, BLAST was run on the sequences in order to find the best templates. Pocket detection and identification of functionally and structurally important residues of VHH 3D structure as well as determination of its clefts and ligand binding site were carried out on the structure. ZDOCK docking server predicted all possible binding modes in the translational and rotational space between the selected region of Bap as an antigen and the VHH structure as an antibody.

CONCLUSION: We identified the amino acids involved in antigen-VHH interactions. Some functional conserved residues located in the largest cleft that participate in ligand binding site are identified. It seems that these amino acids are involved in antigen-VHH interactions.}, } @article {pmid26906117, year = {2016}, author = {Sato, VS and Jorge, JA and Guimarães, LH}, title = {Characterization of a Thermotolerant Phytase Produced by Rhizopus microsporus var. microsporus Biofilm on an Inert Support Using Sugarcane Bagasse as Carbon Source.}, journal = {Applied biochemistry and biotechnology}, volume = {179}, number = {4}, pages = {610-624}, doi = {10.1007/s12010-016-2018-7}, pmid = {26906117}, issn = {1559-0291}, mesh = {6-Phytase/biosynthesis/chemistry/*isolation & purification ; Biofilms/growth & development ; Carbon/*chemistry ; Cellulose/chemistry ; Hydrogen-Ion Concentration ; Hydrolysis ; Kinetics ; Phytic Acid/chemistry ; Rhizopus/chemistry/*enzymology ; Saccharum/chemistry ; Substrate Specificity ; Temperature ; }, abstract = {The Rhizopus microsporus var. microsporus biofilm was able to produce increased levels of an extracellular thermotolerant phytase using polyethylene and viscose as an inert support in both modified NBRIP medium and modified Khanna medium containing sugarcane bagasse as the carbon source. The enzyme production was strictly regulated by the phosphorus content with optimal production at 0.5 mM of sodium phytate and KH2PO4. The extracellular phytase, RMPhy1, was purified 4.18-fold with 4.78 % recovery using DEAE-cellulose and CM-cellulose. A single protein band with a molecular mass of 35.4 kDa was obtained when the samples were subjected to 10 % SDS-PAGE. The optimum temperature for activity was 55 °C and the optimum pH was 4.5. R. microsporus var. microsporus phytase exhibited high stability at 30 and 40 °C with a half-life of 115 min at 60 °C. The enzyme activity increased in the presence of Ca (2+) and was inhibited by Zn(2+), arsenate, and sodium phosphate. Phytase demonstrated high substrate specificity for sodium phytate with K m = 0.72 mM and V max = 94.55 U/mg of protein and for p-NPP with K m = 0.04 mM and V max = 106.38 U/mg of protein. The enzyme also hydrolyzed ATP, AMPc, glucose 6-phosphate, glucose 1-phosphate, and UDPG. This is the first report on phytase characterization delivered with biofilm technology. The properties of the enzyme account for its high potential for use in biotechnology and the possibility of application in different industrial sectors as feed in the future.}, } @article {pmid26905659, year = {2016}, author = {Fernandes, RA and Monteiro, DR and Arias, LS and Fernandes, GL and Delbem, AC and Barbosa, DB}, title = {Biofilm formation by Candida albicans and Streptococcus mutans in the presence of farnesol: a quantitative evaluation.}, journal = {Biofouling}, volume = {32}, number = {3}, pages = {329-338}, doi = {10.1080/08927014.2016.1144053}, pmid = {26905659}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects/growth & development ; *Candida albicans/drug effects/physiology ; Colony Count, Microbial/methods ; Farnesol/*pharmacology ; Humans ; Microscopy, Electron, Scanning/methods ; Mouth/microbiology ; *Streptococcus mutans/drug effects/physiology ; }, abstract = {The aim of this study was to evaluate the effect of the QS molecule farnesol on single and mixed species biofilms formed by Candida albicans and Streptococcus mutans. The anti-biofilm effect of farnesol was assessed through total biomass quantification, counting of colony forming units (CFUs) and evaluation of metabolic activity. Biofilms were also analyzed by scanning electron microscopy (SEM). It was observed that farnesol reduced the formation of single and mixed biofilms, with significant reductions of 37% to 90% and 64% to 96%, respectively, for total biomass and metabolic activity. Regarding cell viability, farnesol treatment promoted significant log reductions in the number of CFUs, ie 1.3-4.2 log10 and 0.67-5.32 log10, respectively, for single and mixed species biofilms. SEM images confirmed these results, showing decreases in the number of cells in all biofilms. In conclusion, these findings highlight the role of farnesol as an alternative agent with the potential to reduce the formation of pathogenic biofilms.}, } @article {pmid26905384, year = {2016}, author = {Maske, TT and Brauner, KV and Nakanishi, L and Arthur, RA and van de Sande, FH and Cenci, MS}, title = {An in vitro dynamic microcosm biofilm model for caries lesion development and antimicrobial dose-response studies.}, journal = {Biofouling}, volume = {32}, number = {3}, pages = {339-348}, doi = {10.1080/08927014.2015.1130824}, pmid = {26905384}, issn = {1029-2454}, mesh = {Animals ; *Biofilms/drug effects/growth & development ; Cattle ; Chlorhexidine/*pharmacology ; Colony Count, Microbial/methods ; *Dental Caries/diagnosis/etiology/microbiology/prevention & control ; Dental Enamel/drug effects/pathology ; Dose-Response Relationship, Drug ; Hardness Tests/methods ; Humans ; Models, Biological ; Mouthwashes/pharmacology ; Saliva/microbiology ; *Tooth Demineralization/diagnosis/prevention & control ; }, abstract = {Some dynamic biofilm models for dental caries development are limited as they require multiple experiments and do not allow independent biofilm growth units, making them expensive and time-consuming. This study aimed to develop and test an in vitro dynamic microcosm biofilm model for caries lesion development and for dose-response to chlorhexidine. Microcosm biofilms were grown under two different protocols from saliva on bovine enamel discs for up to 21 days. The study outcomes were as follows: the percentage of enamel surface hardness change, integrated hardness loss, and the CFU counts from the biofilms formed. The measured outcomes, mineral loss and CFU counts showed dose-response effects as a result of the treatment with chlorhexidine. Overall, the findings suggest that biofilm growth for seven days with 0.06 ml min(-1) salivary flow under exposure to 5% sucrose (3 × daily, 0.25 ml min(-1), 6 min) was suitable as a pre-clinical model for enamel demineralization and antimicrobial studies.}, } @article {pmid26905178, year = {2016}, author = {Mercier, A and Bertaux, J and Lesobre, J and Gravouil, K and Verdon, J and Imbert, C and Valette, E and Héchard, Y}, title = {Characterization of biofilm formation in natural water subjected to low-frequency electromagnetic fields.}, journal = {Biofouling}, volume = {32}, number = {3}, pages = {287-299}, doi = {10.1080/08927014.2015.1137896}, pmid = {26905178}, issn = {1029-2454}, mesh = {Animals ; *Biofilms/growth & development/radiation effects ; Biota/physiology/radiation effects ; *Electromagnetic Fields ; *Plankton/physiology/radiation effects ; *Proteobacteria/physiology/radiation effects ; *Thoracica/physiology/radiation effects ; }, abstract = {Electromagnetic field (EMF) treatment has proven to be effective against mineral scaling in water systems. Therefore, it should be assessed for the treatment of other deposits such as biofilms. In this study, a commercial device producing low-frequency EMF (1-10 kHz) was applied to a reactor fed with natural water for 45 days. The treatment promoted the concentration of microorganisms in suspension and limited the amount of sessile microorganisms in the biofilm, as determined by the measurement of total DNA, qPCR and microscopy. The structure of the bacterial community was assessed by t-RFLP and pyrosequencing analysis. The results showed that EMF treatment affected both planktonic and sessile community composition. EMFs were responsible for a shift in classes of Proteobacteria during development of the biofilm. It may be speculated that the EMF treatment affected particle solubility and/or microorganism hydration. This study indicated that EMFs modulated biofilm formation in natural water.}, } @article {pmid26904749, year = {2015}, author = {Alasil, SM and Omar, R and Ismail, S and Yusof, MY}, title = {Inhibition of Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa by Culture Extract from Novel Bacterial Species of Paenibacillus Using a Rat Model of Chronic Lung Infection.}, journal = {International journal of bacteriology}, volume = {2015}, number = {}, pages = {671562}, pmid = {26904749}, issn = {2356-6957}, abstract = {Quorum sensing (QS) is a key regulator of virulence factors and biofilm formation in Gram-negative bacteria such as Pseudomonas aeruginosa. Microorganisms that inhabit soil are of strategic importance in the discovery of compounds with anti-QS properties. The objective of the study was to test the culture extract of a taxonomically novel species of Paenibacillus strain 139SI for its inhibitory effects on the QS-controlled virulence factors and biofilm formation of Pseudomonas aeruginosa both in vitro and in vivo. The Paenibacillus sp. culture extract was used to test its anti-QS effects on the LasA protease, LasB elastase, pyoverdin production, and biofilm formation of P. aeruginosa as well as evaluate its therapeutic effects on lung bacteriology, pathology, hematological profile, and serum antibody responses of experimental animals in a rat model of chronic lung infection. Results showed significant decrease in the activities of QS-controlled LasA protease, LasB elastase pyoverdin, and biofilm formation of P. aeruginosa caused by the culture extract. Moreover, the extract significantly prolonged the survival times of rats and facilitated the clearance of biofilm infections from infected lungs. In conclusion, the antiquorum sensing effects of culture extract from a novel species of Paenibacillus provide new insights to combat biofilm-associated infections.}, } @article {pmid26904018, year = {2016}, author = {Di Pasquale, P and Caterino, M and Di Somma, A and Squillace, M and Rossi, E and Landini, P and Iebba, V and Schippa, S and Papa, R and Selan, L and Artini, M and Palamara, AT and Duilio, A}, title = {Exposure of E. coli to DNA-Methylating Agents Impairs Biofilm Formation and Invasion of Eukaryotic Cells via Down Regulation of the N-Acetylneuraminate Lyase NanA.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {147}, pmid = {26904018}, issn = {1664-302X}, abstract = {DNA methylation damage can be induced by endogenous and exogenous chemical agents, which has led every living organism to develop suitable response strategies. We investigated protein expression profiles of Escherichia coli upon exposure to the alkylating agent methyl-methane sulfonate (MMS) by differential proteomics. Quantitative proteomic data showed a massive downregulation of enzymes belonging to the glycolytic pathway and fatty acids degradation, strongly suggesting a decrease of energy production. A strong reduction in the expression of the N-acetylneuraminate lyases (NanA) involved in the sialic acid metabolism was also observed. Using a null NanA mutant and DANA, a substrate analog acting as competitive inhibitor, we demonstrated that down regulation of NanA affects biofilm formation and adhesion properties of E. coli MV1161. Exposure to alkylating agents also decreased biofilm formation and bacterial adhesion to Caco-2 eukaryotic cell line by the adherent invasive E. coli (AIEC) strain LF82. Our data showed that methylation stress impairs E. coli adhesion properties and suggest a possible role of NanA in biofilm formation and bacteria host interactions.}, } @article {pmid26904013, year = {2016}, author = {Feldman, M and Ginsburg, I and Al-Quntar, A and Steinberg, D}, title = {Thiazolidinedione-8 Alters Symbiotic Relationship in C. albicans-S. mutans Dual Species Biofilm.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {140}, pmid = {26904013}, issn = {1664-302X}, abstract = {The small molecule, thiazolidinedione-8 (S-8) was shown to impair biofilm formation of various microbial pathogens, including the fungus Candida albicans and Streptococcus mutans. Previously, we have evaluated the specific molecular mode of S-8 action against C. albicans biofilm-associated pathogenicity. In this study we investigated the influence of S-8 on dual species, C. albicans-S. mutans biofilm. We show that in the presence of S-8 a reduction of the co-species biofilm formation occurred with a major effect on C. albicans. Biofilm biomass and exopolysaccharide (EPS) production were significantly reduced by S-8. Moreover, the agent caused oxidative stress associated with a strong induction of reactive oxygen species and hydrogen peroxide uptake inhibition by a mixed biofilm. In addition, S-8 altered symbiotic relationship between these species by a complex mechanism. Streptococcal genes associated with quorum sensing (QS) (comDE and luxS), EPS production (gtfBCD and gbpB), as well as genes related to protection against oxidative stress (nox and sodA) were markedly upregulated by S-8. In contrast, fungal genes related to hyphae formation (hwp1), adhesion (als3), hydrophobicity (csh1), and oxidative stress response (sod1, sod2, and cat1) were downregulated in the presence of S-8. In addition, ywp1 gene associated with yeast form of C. albicans was induced by S-8, which is correlated with appearance of mostly yeast cells in S-8 treated dual species biofilms. We concluded that S-8 disturbs symbiotic balance between C. albicans and S. mutans in dual species biofilm.}, } @article {pmid26903968, year = {2016}, author = {Wang, Z and Xiang, Q and Yang, T and Li, L and Yang, J and Li, H and He, Y and Zhang, Y and Lu, Q and Yu, J}, title = {Autoinducer-2 of Streptococcus mitis as a Target Molecule to Inhibit Pathogenic Multi-Species Biofilm Formation In Vitro and in an Endotracheal Intubation Rat Model.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {88}, pmid = {26903968}, issn = {1664-302X}, abstract = {Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns' endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, we also found that exogenous AI-2 and S. mitis could influence the behaviors of P. aeruginosa. We hypothesized that S. mitis contributes to this interspecies interaction and that inhibition of AI-2 could result in inhibition of these effects. To test this hypothesis, we selected PAO1 as a representative model strain of P. aeruginosa and evaluated the effect of S. mitis as well as an AI-2 analog (D-ribose) on mono- and co-culture biofilms in both in vitro and in vivo models. In this context, S. mitis promoted PAO1 biofilm formation and pathogenicity. Dual-species (PAO1 and S. mitis) biofilms exhibited higher expression of quorum sensing genes than single-species (PAO1) biofilms did. Additionally, ETTs covered in dual-species biofilms increased the mortality rate and aggravated lung infection compared with ETTs covered in mono-species biofilms in an endotracheal intubation rat model, all of which was inhibited by D-ribose. Our results demonstrated that S. mitis AI-2 plays an important role in interspecies interactions with PAO1 and may be a target for inhibition of biofilm formation and infection in ventilator-associated pneumonia.}, } @article {pmid26903956, year = {2016}, author = {Feng, J and Weitner, M and Shi, W and Zhang, S and Zhang, Y}, title = {Eradication of Biofilm-Like Microcolony Structures of Borrelia burgdorferi by Daunomycin and Daptomycin but not Mitomycin C in Combination with Doxycycline and Cefuroxime.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {62}, pmid = {26903956}, issn = {1664-302X}, support = {R01 AI099512/AI/NIAID NIH HHS/United States ; R21 AI108535/AI/NIAID NIH HHS/United States ; }, abstract = {Lyme disease, caused by Borrelia burgdorferi, is the most common vector-borne disease in the United States and Europe. While the majority of Lyme disease patients can resolve their symptoms if treated promptly, 10-20% of patients suffer from prolonged symptoms called post-treatment Lyme disease syndrome (PTLDS). Although the cause for PTLDS is unclear, one possibility is the presence of bacterial persisters not effectively cleared by the current Lyme antibiotics. Recent studies identified several drug candidates including daptomycin, daunomycin, doxorubicin, and mitomycin C that had good activity against B. burgdorferi persisters. However, their relative activities against B. burgdorferi persisters have not been evaluated under the same conditions. In this study, we tested the anti-persister activities of these drugs against both 7-day and 15-day old stationary phase cultures of B. burgdorferi individually as well as in combination with Lyme antibiotics doxycycline and cefuroxime (Ceftin). Our findings demonstrate daunomycin and daptomycin were more active than mitomycin C in single drug comparison at 10 and 20 μM, as well as in drug combinations with doxycycline and cefuroxime. In addition, daunomycin was more active than doxorubicin which correlated with their ability to stain and accumulate in B. burgdorferi. The two drug combination of doxycycline and cefuroxime was unable to eradicate biofilm-like microcolonies of B. burgdorferi persisters. However, the addition of either daunomycin or daptomycin to the doxycycline + cefuroxime combination completely eradicated the biofilm-like structures and produced no visible bacterial regrowth after 7 and 21 days, while the addition of doxorubicin was unable to prevent regrowth at either 7 or 21 day subculture. Mitomycin C in combination with doxycycline and cefuroxime caused no regrowth at 7 days but visible spirochetal regrowth occurred after 21 day subculture. Furthermore, we found that cefuroxime (Ceftin), the third commonly used and most active antibiotic to treat Lyme disease, could replace cefoperazone (a drug no longer available in the US) in the daptomycin + doxycycline combination with complete eradication of the biofilm-like structures as shown by lack of any regrowth in subcultures. Our findings may have implications for improved treatment of Lyme disease.}, } @article {pmid26903564, year = {2016}, author = {Smith-Palmer, T and Lin, S and Oguejiofor, I and Leng, T and Pustam, A and Yang, J and Graham, LL and Wyeth, RC and Bishop, CD and DeMont, ME and Pink, D}, title = {In Situ Confocal Raman Microscopy of Hydrated Early Stages of Bacterial Biofilm Formation on Various Surfaces in a Flow Cell.}, journal = {Applied spectroscopy}, volume = {70}, number = {2}, pages = {289-301}, doi = {10.1177/0003702815620539}, pmid = {26903564}, issn = {1943-3530}, mesh = {Biofilms/*growth & development ; Cell Movement ; Glass ; Microscopy, Confocal/*methods ; Polyethylene Glycols ; Pseudoalteromonas/physiology ; Spectrum Analysis, Raman/*methods ; }, abstract = {Bacterial biofilms are precursors to biofouling by other microorganisms. Understanding their initiation may allow us to design better ways to inhibit them, and thus to inhibit subsequent biofouling. In this study, the ability of confocal Raman microscopy to follow the initiation of biofouling by a marine bacterium, Pseudoalteromonas sp. NCIMB 2021 (NCIMB 2021), in a flow cell, using optical and confocal Raman microscopy, was investigated. The base of the flow cell comprised a cover glass. The cell was inoculated and the bacteria attached to, and grew on, the cover glass. Bright field images and Raman spectra were collected directly from the hydrated biofilms over several days. Although macroscopically the laser had no effect on the biofilm, within the first 24 h cells migrated away from the position of the laser beam. In the absence of flow, a buildup of extracellular substances occurred at the base of the biofilm. When different coatings were applied to cover glasses before they were assembled into the flow cells, the growth rate, structure, and composition of the resulting biofilm was affected. In particular, the ratio of Resonance Raman peaks from cytochrome c (CC) in the extracellular polymeric substances, to the Raman phenylalanine (Phe) peak from protein in the bacteria, depended on both the nature of the surface and the age of the biofilm. The ratios were highest for 24 h colonies on a hydrophobic surface. Absorption of a surfactant with an ethyleneoxy chain into the hydrophobic coating created a surface similar to that given with a simple PEG coating, where bacteria grew in colonies away from the surface rather than along the surface, and CC:Phe ratios were initially low but increased at least fivefold in the first 48 h.}, } @article {pmid26903175, year = {2016}, author = {Bojsen, R and Regenberg, B and Gresham, D and Folkesson, A}, title = {A common mechanism involving the TORC1 pathway can lead to amphotericin B-persistence in biofilm and planktonic Saccharomyces cerevisiae populations.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {21874}, pmid = {26903175}, issn = {2045-2322}, support = {R01 GM107466/GM/NIGMS NIH HHS/United States ; 1R01GM107466-01/GM/NIGMS NIH HHS/United States ; }, mesh = {Amphotericin B/*pharmacology ; Antifungal Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/drug effects/genetics/metabolism ; Candida glabrata/drug effects/genetics/metabolism ; Drug Resistance, Fungal/*genetics ; Ergosterol/metabolism ; *Gene Expression Regulation, Fungal ; Mutation ; Phosphatidylinositol 3-Kinases/genetics/metabolism ; Plankton/*drug effects/genetics/metabolism ; Ribosomes/drug effects/metabolism ; Saccharomyces cerevisiae/*drug effects/genetics/metabolism ; Saccharomyces cerevisiae Proteins/antagonists & inhibitors/*genetics/metabolism ; Sequence Analysis, DNA ; Signal Transduction ; Sirolimus/pharmacology ; Transcription Factors/antagonists & inhibitors/*genetics/metabolism ; ras Proteins/genetics/metabolism ; }, abstract = {Fungal infections are an increasing clinical problem. Decreased treatment effectiveness is associated with biofilm formation and drug recalcitrance is thought to be biofilm specific. However, no systematic investigations have tested whether resistance mechanisms are shared between biofilm and planktonic populations. We performed multiplexed barcode sequencing (Bar-seq) screening of a pooled collection of gene-deletion mutants cultivated as biofilm and planktonic cells. Screening for resistance to the ergosterol-targeting fungicide amphotericin B (AmB) revealed that the two growth modes had significant overlap in AmB-persistent mutants. Mutants defective in sterol metabolism, ribosome biosynthesis, and the TORC1 and Ras pathways showed increased persistence when treated with AmB. The ras1, ras2 and tor1 mutants had a high-persister phenotype similar to wild-type biofilm and planktonic cells exposed to the TORC1 pathway inhibitor rapamycin. Inhibition of TORC1 with rapamycin also increased the proportion of persisters in Candida albicans and Candida glabrata. We propose that decreased TORC1-mediated induction of ribosome biosynthesis via Ras can lead to formation of AmB-persister cells regardless of whether the cells are in planktonic or biofilm growth mode. Identification of common pathways leading to growth mode-independent persister formation is important for developing novel strategies for treating fungal infections.}, } @article {pmid26903148, year = {2016}, author = {Heidari, AE and Moghaddam, S and Truong, KK and Chou, L and Genberg, C and Brenner, M and Chena, Z}, title = {Errata: Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography.}, journal = {Journal of biomedical optics}, volume = {21}, number = {2}, pages = {29802}, pmid = {26903148}, issn = {1560-2281}, } @article {pmid26902505, year = {2016}, author = {Shi, D and Zhao, Y and Yan, H and Fu, H and Shen, Y and Lu, G and Mei, H and Qiu, Y and Li, D and Liu, W}, title = {Antifungal effects of undecylenic acid on the biofilm formation of Candida albicans.}, journal = {International journal of clinical pharmacology and therapeutics}, volume = {54}, number = {5}, pages = {343-353}, doi = {10.5414/CP202460}, pmid = {26902505}, issn = {0946-1965}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/genetics/growth & development/metabolism/pathogenicity ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Fungal/drug effects ; Microbial Viability/drug effects ; Undecylenic Acids/*pharmacology ; Virulence Factors/metabolism ; }, abstract = {Undecylenic acid can effectively control skin fungal infection, but the mechanism of its fungal inhibition is unclear. Hyphal growth of Candida albicans (C. albicans) and biofilm formation have been well recognized as important virulence factors for the initiation of skin infection and late development of disseminated infection. In this study, we seek to investigate antifungal mechanisms of undecylenic acid by evaluating the virulence factors of C. albicans during biofilm formation. We found that undecylenic acid inhibits biofilm formation of C. albicans effectively with optimal concentration above 3 mM. In the presence of this compound, the morphological transition from yeast to filamentous phase is abolished ultimately when the concentration of undecylenic acid is above 4 mM. Meanwhile, the cell surface is crumpled, and cells display an atrophic appearance under scanning electron microscopy even with low concentration of drug treatment. On the other hand, the drug treatment decreases the transcriptions of hydrolytic enzymes such as secreted aspartic protease, lipase, and phospholipase. Hyphal formation related genes, like HWP1, are significantly reduced in transcriptional level in drug-treated biofilm condition as well. The down-regulated profile of these genes leads to a poorly organized biofilm in undecylenic acid treated environment.}, } @article {pmid26901587, year = {2016}, author = {Gambino, M and Cappitelli, F}, title = {Mini-review: Biofilm responses to oxidative stress.}, journal = {Biofouling}, volume = {32}, number = {2}, pages = {167-178}, doi = {10.1080/08927014.2015.1134515}, pmid = {26901587}, issn = {1029-2454}, mesh = {*Bacteria/metabolism/pathogenicity ; Biofilms/*growth & development ; Humans ; Oxidation-Reduction ; *Oxidative Stress ; Polysaccharides/biosynthesis ; Quorum Sensing ; Reactive Oxygen Species/metabolism ; }, abstract = {Biofilms constitute the predominant microbial style of life in natural and engineered ecosystems. Facing harsh environmental conditions, microorganisms accumulate reactive oxygen species (ROS), potentially encountering a dangerous condition called oxidative stress. While high levels of oxidative stress are toxic, low levels act as a cue, triggering bacteria to activate effective scavenging mechanisms or to shift metabolic pathways. Although a complex and fragmentary picture results from current knowledge of the pathways activated in response to oxidative stress, three main responses are shown to be central: the existence of common regulators, the production of extracellular polymeric substances, and biofilm heterogeneity. An investigation into the mechanisms activated by biofilms in response to different oxidative stress levels could have important consequences from ecological and economic points of view, and could be exploited to propose alternative strategies to control microbial virulence and deterioration.}, } @article {pmid26900881, year = {2016}, author = {Xia, Y and Zhao, J and Li, M and Zhang, S and Li, S and Li, W}, title = {Bioelectrochemical Reduction of Fe(II)EDTA-NO in a Biofilm Electrode Reactor: Performance, Mechanism, and Kinetics.}, journal = {Environmental science & technology}, volume = {50}, number = {7}, pages = {3846-3851}, doi = {10.1021/acs.est.5b05861}, pmid = {26900881}, issn = {1520-5851}, mesh = {Air Pollutants/chemistry/metabolism ; Biofilms ; *Bioreactors/microbiology ; Chelating Agents/chemistry ; Edetic Acid/chemistry/*metabolism ; Electrochemical Techniques/instrumentation/methods ; Electrodes ; Equipment Design ; Ferrous Compounds/chemistry/*metabolism ; Kinetics ; Nitric Oxide/chemistry/*metabolism ; Oxidation-Reduction ; }, abstract = {A biofilm electrode reactor (BER) is proposed to effectively regenerate Fe(II)EDTA, a solvent for NOx removal from flue gas, from Fe(II)EDTA-NO, a spent solution. In this study, the performance, mechanism, and kinetics of the bioelectrochemical reduction of Fe(II)EDTA-NO were investigated. The pathways of Fe(II)EDTA-NO reduction were investigated via determination of nitrogen element balance in the BER and an abiotic electrode reactor. The experimental results indicate that the chelated NO (Fe(II)EDTA-NO) is reduced to N2 with N2O as an intermediate. However, the oxidation of NO occurred in the absence of Fe(II)EDTA in abiotic reactors. Furthermore, the accumulation of N2O was suppressed with the help of electricity. The preponderant electron donor for reduction of Fe(II)EDTA-NO was also confirmed via analysis of the electron conservation. About 87% of Fe(II)EDTA-NO was reduced using Fe(II)EDTA as the electron donor in the presence of both glucose and cathode electrons while the cathode electrons were utilized for the reduction of Fe(III)EDTA to Fe(II)EDTA. Michaelis-Menten kinetic constants of bioelectrochemical reduction of Fe(II)EDTA-NO were also calculated. The maximum reduction rate of Fe(II)EDTA-NO was 13.04 mol m(-3) h(-1), which is 50% higher than that in a conventional biofilter.}, } @article {pmid26900701, year = {2016}, author = {Sharma, VK and Kudva, IT and Bearson, BL and Stasko, JA}, title = {Contributions of EspA Filaments and Curli Fimbriae in Cellular Adherence and Biofilm Formation of Enterohemorrhagic Escherichia coli O157:H7.}, journal = {PloS one}, volume = {11}, number = {2}, pages = {e0149745}, pmid = {26900701}, issn = {1932-6203}, mesh = {*Bacterial Adhesion ; *Biofilms ; Escherichia coli O157/*physiology ; Escherichia coli Proteins/*genetics/*metabolism ; Fimbriae, Bacterial/*genetics/*metabolism ; Gene Expression Regulation, Bacterial ; Glucose/metabolism ; Temperature ; }, abstract = {In Escherichia coli O157:H7 (O157), the filamentous structure of the type III secretion system is produced from the polymerization of the EspA protein. EspA filaments are essential for O157 adherence to epithelial cells. In previous studies, we demonstrated that O157 hha deletion mutants showed increased adherence to HEp-2 cells and produced abundant biofilms. Transcriptional analysis revealed increased expression of espA as well as the csgA gene, which encodes curli fimbriae that are essential for biofilm formation. In the present study, we constructed hha espA, hha csgA, and hha csgA espA deletion mutants to determine the relative importance of EspA and CsgA in O157 adherence to HEp-2 cells and biofilm formation. In vitro adherence assays, conducted at 37°C in a tissue culture medium containing 0.1% glucose, showed that HEp-2 cell adherence required EspA because hha espA and hha csgA espA mutants adhered to HEp-2 cells at higher levels only when complemented with an espA-expressing plasmid. Biofilm assays performed at 28°C in a medium lacking glucose showed dependency of biofilm formation on CsgA; however EspA was not produced under these conditions. Despite production of detectable levels of EspA at 37°C in media supplemented with 0.1% glucose, the biofilm formation occurred independent of EspA. These results indicate dependency of O157 adherence to epithelial cells on EspA filaments, while CsgA promoted biofilm formation under conditions mimicking those found in the environment (low temperature with nutrient limitations) and in the digestive tract of an host animal (higher temperature and low levels of glucose).}, } @article {pmid26900648, year = {2016}, author = {Piercey, MJ and Hingston, PA and Truelstrup Hansen, L}, title = {Genes involved in Listeria monocytogenes biofilm formation at a simulated food processing plant temperature of 15 °C.}, journal = {International journal of food microbiology}, volume = {223}, number = {}, pages = {63-74}, doi = {10.1016/j.ijfoodmicro.2016.02.009}, pmid = {26900648}, issn = {1879-3460}, mesh = {Benzalkonium Compounds/pharmacology ; Biofilms/drug effects/*growth & development ; Food Handling ; *Food Microbiology ; Listeria monocytogenes/drug effects/*genetics/*growth & development ; Mutagenesis, Insertional ; Stainless Steel ; *Temperature ; }, abstract = {Listeria monocytogenes is a pathogenic foodborne bacterium whose persistence in food processing environments is in part attributed to its biofilm formation. Most biofilm studies have been carried out at 30-37 °C rather than at temperatures found in the food processing plants (i.e., 10-20 °C). The objective of the present study was to mine for novel genes that contribute to L. monocytogenes biofilm formation at 15 °C using the random insertional mutagenesis approach. A library of 11,024 L. monocytogenes 568 (serotype 1/2a) Himar1 insertional mutants was created. Mutants with reduced or enhanced biofilm formation at 15 °C were detected in microtiter plate assays with crystal violet and safranin staining. Fourteen mutants expressed enhanced biofilm phenotypes, and harbored transposon insertions in genes encoding cell wall biosynthesis, motility, metabolism, stress response, and cell surface associated proteins. Deficient mutants (n=5) contained interruptions in genes related to peptidoglycan, teichoic acid, or lipoproteins. Enhanced mutants produced significantly (p<0.05) higher cell densities in biofilm formed on stainless steel (SS) coupons at 15 °C (48 h) than deficient mutants, which were also more sensitive to benzalkonium chloride. All biofilm deficient mutants and four enhanced mutants in the microtiter plate assay (flaA, cheR, lmo2563 and lmo2488) formed no biofilm in a peg lid assay (Calgary biofilm device) while insertions in lmo1224 and lmo0543 led to excess biofilm in all assays. Two enhanced biofilm formers were more resistant to enzymatic removal with DNase, proteinase K or pectinase than the parent strain. Scanning electron microscopy of individual biofilms made by five mutants and the parent on SS surfaces showed formation of heterogeneous biofilm with dense zones by immotile mutants, while deficient mutants exhibited sparse growth. In conclusion, interruptions of 9 genes not previously linked to biofilm formation in L. monocytogenes (lmo2572, lmo2488 (uvrA), lmo1224, lmo0434 (inlB), lmo0263 (inlH), lmo0543, lmo0057 (EsaA), lmo2563, lmo0453), caused enhanced biofilm formation in the bacterium at 15 °C. The remaining mutants harbored interruptions in 10 genetic loci previously associated with biofilm formation at higher temperatures, indicating some temperature driven differences in the formation of biofilm by L. monocytogenes.}, } @article {pmid26899861, year = {2016}, author = {Pemmaraju, SC and Pruthi, PA and Prasad, R and Pruthi, V}, title = {Modulation of Candida albicans Biofilm by Different Carbon Sources.}, journal = {Mycopathologia}, volume = {181}, number = {5-6}, pages = {341-352}, pmid = {26899861}, issn = {1573-0832}, mesh = {Biofilms/*growth & development ; Candida albicans/growth & development/metabolism/*physiology ; Carbohydrate Metabolism ; Carbon/*metabolism ; Cell Wall/chemistry ; Formazans/analysis ; Lactates/metabolism ; Microscopy, Atomic Force ; Spectroscopy, Fourier Transform Infrared ; Staining and Labeling ; beta-Glucans/analysis ; }, abstract = {In the present investigation, the role of carbon sources (glucose, lactate, sucrose, and arabinose) on Candida albicans biofilm development and virulence factors was studied on polystyrene microtiter plates. Besides this, structural changes in cell wall component β-glucan in presence of different carbon sources have also been highlighted. Biofilm formation was analyzed by XTT (2,3-bis[2-Methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay. Glucose-grown cells exhibited the highest metabolic activity during adhesion among all carbon sources tested (p < 0.05). However, cells exposed to sucrose exhibited highest biofilm formation and matrix polysaccharides secretion after 48 h. The results also correlated with the biofilm height and roughness measurements by atomic force microscopy. Exposure to lactate induced hyphal structures with the highest proteinase activity while arabinose-grown cells formed pseudohyphal structures possessing the highest phospholipase activity. Structural changes in β-glucan characterized by Fourier transform infrared (FTIR) spectroscopy displayed characteristic band of β-glucan at 892 cm(-1) in all carbon sources tested. The β(1→6) to β(1→3) glucan ratio calculated as per the band area of the peak was less in lactate (1.15) as compared to glucose (1.73), sucrose (1.62), and arabinose (2.85). These results signify that carbon sources influence C. albicans biofilm development and modulate virulence factors and structural organization of cell wall component β-glucan.}, } @article {pmid26897582, year = {2017}, author = {Cabrera-Orozco, A and Galíndez-Nájera, SP and Ruiz-Ordaz, N and Galíndez-Mayer, J and Martínez-Jerónimo, F}, title = {Biodegradation of a commercial mixture of the herbicides atrazine and S-metolachlor in a multi-channel packed biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {33}, pages = {25656-25665}, pmid = {26897582}, issn = {1614-7499}, support = {SIP IPN 20130821//Instituto Politécnico Nacional/International ; }, mesh = {Acetamides/*metabolism ; Atrazine/*metabolism ; Biodegradation, Environmental ; *Biofilms ; Bioreactors ; Environmental Restoration and Remediation/*methods ; Herbicides/*metabolism ; Microbiota/*physiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Atrazine and S-metolachlor are two of the most widely used herbicides for agricultural purposes; consequently, residues of both compounds and their metabolites had been detected in ground and superficial waters. Unlike atrazine, the complete degradation of metolachlor has not been achieved. Hence, the purpose of this research is to study the biodegradation of a commercial mixture of atrazine and S-metolachlor in a prototype of a multi-channel packed-bed-biofilm reactor (MC-PBR) designed with the aim of solving the problems of pressure drop and oxygen transfer, typically found on this type of bioreactors.Because the removal efficiency of the herbicides was increased when Candida tropicalis was added to the original microbial community isolated, the reactor was inoculated with this enriched community. The operational conditions tested in batch and continuous mode did not affect the removal efficiency of atrazine; however, this was not the case for S-metolachlor. The removal rates and efficiencies showed a notable variation along the MC-PBR operation.}, } @article {pmid26896716, year = {2016}, author = {Yan, M and Zhao, L and Bao, M and Lu, J}, title = {Hydrolyzed polyacrylamide biodegradation and mechanism in sequencing batch biofilm reactor.}, journal = {Bioresource technology}, volume = {207}, number = {}, pages = {315-321}, doi = {10.1016/j.biortech.2016.01.083}, pmid = {26896716}, issn = {1873-2976}, mesh = {Acrylic Resins/*metabolism ; Bacteria/genetics/isolation & purification/*metabolism ; Bacteroidetes/genetics/isolation & purification/metabolism ; Biodegradation, Environmental ; Biofilms ; Bioreactors ; Carbon/metabolism ; High-Throughput Nucleotide Sequencing ; Hydrolysis ; Planctomycetales/genetics/isolation & purification/metabolism ; Proteobacteria/genetics/isolation & purification/metabolism ; Sewage/chemistry/microbiology ; Waste Disposal, Fluid/*methods ; Wastewater/*chemistry/microbiology ; Water Pollutants, Chemical/*metabolism ; }, abstract = {An investigation was performed to study the performance of a sequencing batch biofilm reactor (SBBR) to treat hydrolyzed polyacrylamides (HPAMs) and to determine the mechanisms of HPAM biodegradation. The mechanisms for the optimized parameters that significantly improved the degradation efficiency of the HPAMs were investigated by a synergistic effect of the co-metabolism in the sludge and the enzyme activities. The HPAM and TOC removal ratio reached 54.69% and 70.14%. A significant decrease in the total nitrogen concentration was measured. The carbon backbone of the HPAMs could be degraded after the separation of the amide group according to the data analysis. The HPLC results indicated that the HPAMs could be converted to polymer fragments without the generation of the acrylamide monomer intermediate. The results from high-throughput sequencing analysis revealed proteobacterias, bacteroidetes and planctomycetes were the key microorganisms involved in the degradation.}, } @article {pmid26896715, year = {2016}, author = {Li, J and Jin, R and Liu, G and Tian, T and Wang, J and Zhou, J}, title = {Simultaneous removal of chromate and nitrate in a packed-bed bioreactor using biodegradable meal box as carbon source and biofilm carriers.}, journal = {Bioresource technology}, volume = {207}, number = {}, pages = {308-314}, doi = {10.1016/j.biortech.2016.02.005}, pmid = {26896715}, issn = {1873-2976}, mesh = {Bacteria/drug effects/metabolism ; Biodegradation, Environmental/drug effects ; Biofilms/*drug effects ; Biological Oxygen Demand Analysis ; Bioreactors/*microbiology ; Carbon/*pharmacology ; Chromates/*isolation & purification ; Denitrification/drug effects ; Nitrates/*isolation & purification ; Nitrites/analysis ; Waste Disposal, Fluid ; }, abstract = {An up-flow packed-bed bioreactor was constructed to investigate the simultaneous removal of chromate and nitrate using biodegradable meal box as carbon source and biofilm carriers. The bioreactor was operated for 164days with varying influent Cr(VI) concentrations (2.0-50.0mg/L) and hydraulic retention times (HRT, 10-24h). It was shown that complete denitrification and Cr(VI) reduction could be achieved when influent Cr(VI) concentrations were lower than 20mg/L with a HRT of 17h. Shortening the HRT could significantly reduce the effluent CODcr. It was also observed that Cr(III) was mainly immobilized on the biofilm. Further investigation on Cr distribution in the biofilm compartments indicated that Cr(VI) reduction occurred in all compartments and the intercellular Cr was dominant. High-throughput sequencing analysis showed that Proteobacteria, Bacteroidetes and Firmicutes were the dominant phyla in the biofilm and Cr(VI) stress had a negative effect on the abundance of most bacteria.}, } @article {pmid26896562, year = {2016}, author = {Ribeiro, SM and Felício, MR and Boas, EV and Gonçalves, S and Costa, FF and Samy, RP and Santos, NC and Franco, OL}, title = {New frontiers for anti-biofilm drug development.}, journal = {Pharmacology & therapeutics}, volume = {160}, number = {}, pages = {133-144}, doi = {10.1016/j.pharmthera.2016.02.006}, pmid = {26896562}, issn = {1879-016X}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology/*therapeutic use ; Biofilms/*drug effects ; Drug Resistance, Bacterial/drug effects ; Humans ; }, abstract = {Pathogenic microbial biofilm, a consortium of microbial cells protected by a self-produced polymer matrix, is considered a worldwide challenge due to the inherent antibiotic resistance conferred by its lifestyle. Living, as it does, in a community of microbial organisms in a clinical situation, makes it responsible for severe and dangerous cases of infection. Combating this organisation of cells usually requires high antibiotic doses for a prolonged time, and these approaches often fail, contributing to infection persistence. In addition to therapeutic limitations, biofilms can be a source of infections when they grow in medical devices. The challenge imposed by biofilms has mobilised researchers in the entire world to prospect or develop alternatives to control biofilms. In this context, this review summarises the new frontiers that could be used in clinical circumstances in order to prevent or eliminate pathogenic biofilms.}, } @article {pmid26896504, year = {2016}, author = {Luther, MK and Mermel, LA and LaPlante, KL}, title = {Comparison of telavancin and vancomycin lock solutions in eradication of biofilm-producing staphylococci and enterococci from central venous catheters.}, journal = {American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists}, volume = {73}, number = {5}, pages = {315-321}, doi = {10.2146/ajhp150029}, pmid = {26896504}, issn = {1535-2900}, mesh = {Aminoglycosides/*administration & dosage ; Anti-Bacterial Agents/administration & dosage ; Biofilms/*drug effects ; Catheter-Related Infections/diagnosis/*drug therapy ; Central Venous Catheters/microbiology ; Enterococcus/*drug effects/isolation & purification ; Humans ; Lipoglycopeptides ; Pharmaceutical Solutions/administration & dosage ; Staphylococcus/*drug effects/isolation & purification ; Staphylococcus aureus/drug effects/isolation & purification ; Staphylococcus epidermidis/drug effects/isolation & purification ; Vancomycin/*administration & dosage ; }, abstract = {PURPOSE: Results of a study of the activity of antibiotic lock solutions of vancomycin and telavancin against biofilm-forming strains of Staphylococcus epidermidis, Enterococcus faecalis, and Staphylococcus aureus are reported.

METHODS: An established in vitro central venous catheter model was used to evaluate lock solutions containing vancomycin (5 mg/mL) or telavancin (5 mg/mL), with and without preservative-containing heparin sodium (with 0.45% benzyl alcohol) 2500 units/mL, heparin, and 0.9% sodium chloride solution. Lock solutions were introduced after 24-hour bacterial growth in catheters incubated at 35 °C. After 72 hours of exposure to the lock solutions, catheters were drained, flushed, and cut into segments for quantification of colony-forming units.

RESULTS: Against S. epidermidis, vancomycin and telavancin (with or without heparin) had similar activity. Against E. faecalis, vancomycin alone was more active than telavancin alone (p < 0.01). Against S. aureus, vancomycin plus heparin had activity similar to that of vancomycin alone; both lock agents had greater activity than telavancin (p < 0.02). The addition of heparin was associated with reduced activity of the vancomycin lock solution against S. epidermidis and E. faecalis (p < 0.01). Telavancin activity was not significantly changed with the addition of heparin.

CONCLUSION: In a central venous catheter model, vancomycin and telavancin activity was similar in reducing biofilm-producing S. epidermidis. However, vancomycin was more active than telavancin against E. faecalis and S. aureus. None of the tested agents eradicated biofilm-forming strains. The addition of preservative-containing heparin sodium 2500 units/mL to vancomycin was associated with reduced activity against S. epidermidis and E. faecalis.}, } @article {pmid26895713, year = {2016}, author = {Steenackers, HP and Parijs, I and Dubey, A and Foster, KR and Vanderleyden, J}, title = {Experimental evolution in biofilm populations.}, journal = {FEMS microbiology reviews}, volume = {40}, number = {3}, pages = {373-397}, pmid = {26895713}, issn = {1574-6976}, support = {242670/ERC_/European Research Council/International ; }, mesh = {*Bacterial Physiological Phenomena ; Biodiversity ; *Biofilms ; *Biological Evolution ; Microbial Viability ; Models, Biological ; Phenotype ; }, abstract = {Biofilms are a major form of microbial life in which cells form dense surface associated communities that can persist for many generations. The long-life of biofilm communities means that they can be strongly shaped by evolutionary processes. Here, we review the experimental study of evolution in biofilm communities. We first provide an overview of the different experimental models used to study biofilm evolution and their associated advantages and disadvantages. We then illustrate the vast amount of diversification observed during biofilm evolution, and we discuss (i) potential ecological and evolutionary processes behind the observed diversification, (ii) recent insights into the genetics of adaptive diversification, (iii) the striking degree of parallelism between evolution experiments and real-life biofilms and (iv) potential consequences of diversification. In the second part, we discuss the insights provided by evolution experiments in how biofilm growth and structure can promote cooperative phenotypes. Overall, our analysis points to an important role of biofilm diversification and cooperation in bacterial survival and productivity. Deeper understanding of both processes is of key importance to design improved antimicrobial strategies and diagnostic techniques.}, } @article {pmid26893419, year = {2016}, author = {Edlund, A and Liu, Q and Watling, M and To, TT and Bumgarner, RE and He, X and Shi, W and McLean, JS}, title = {High-Quality Draft Genome Sequence of Low-pH-Active Veillonella parvula Strain SHI-1, Isolated from Human Saliva within an In Vitro Oral Biofilm Model.}, journal = {Genome announcements}, volume = {4}, number = {1}, pages = {}, pmid = {26893419}, issn = {2169-8287}, support = {R01 DE023810/DE/NIDCR NIH HHS/United States ; K99 DE024543/DE/NIDCR NIH HHS/United States ; R00 DE024543/DE/NIDCR NIH HHS/United States ; R01 DE020102/DE/NIDCR NIH HHS/United States ; R01 GM095373/GM/NIGMS NIH HHS/United States ; }, abstract = {We announce here a draft genome sequence of Veillonella parvula strain SHI-1, obtained from healthy human saliva, discovered to be active at low pH using metatranscriptomics within an in vitro oral biofilm model. The genome is composed of 7 contigs, for a total of 2,200,064 bp.}, } @article {pmid26892351, year = {2015}, author = {Gomes, SC and Abascal, CC and Haas, AN and Angst, PD and Oppermann, RV and Marcantonio, RA}, title = {Influence of supragingival biofilm control and smoking habit on Interleukin-1β concentration.}, journal = {Brazilian oral research}, volume = {29}, number = {1}, pages = {S1806-83242015000100302}, doi = {10.1590/1807-3107BOR-2015.vol29.0115}, pmid = {26892351}, issn = {1807-3107}, mesh = {Adult ; *Biofilms ; Dental Plaque/prevention & control ; Enzyme-Linked Immunosorbent Assay ; Female ; Gingival Crevicular Fluid/*chemistry ; Humans ; Interleukin-1beta/*analysis ; Male ; Middle Aged ; Multivariate Analysis ; Periodontal Index ; Periodontitis/*microbiology/*therapy ; Reference Values ; Risk Factors ; Smoking/*adverse effects ; Time Factors ; }, abstract = {This investigation compared gingival crevicular fluid (GCF) interleukin-1β (IL-1β) concentrations in periodontitis patients subjected to a strict supragingival biofilm control (Supra) for 6 months. Never-smokers (23) and smokers (n = 20; 19.6 ± 11.8 cigarettes/day) moderate-to-severe chronic periodontitis patients underwent a 6 months period of supragingival control with weekly recall visits. Periodontal probing depth (PPD), bleeding on probing (BOP) and GCF samples (from different PPD category sites: 3-5 mm and 6-10 mm) were obtained at the baseline, 30, and 180 days. IL-1β was assessed by enzyme-linked immunosorbent assay. Generalized estimating equations were used to fit prediction models of IL-1β changes, considering the dependence between the examinations, and using only data from experimental sites. Overall IL-1β concentrations decreased from 3.2 pg/µL to 1.9 pg/µL. Higher baseline IL-1β concentrations were associated with higher baseline PPD values in both groups. There were no differences in IL-1β concentrations between never-smokers and smokers over time for any PPD category. Higher baseline PPD values and the presence of BOP on day 180 were significantly associated with higher IL-1β concentrations. A strict Supra regimen reduced IL-1β concentrations over time in periodontitis patients. The benefits observed for smokers underline the importance of oral hygiene measures, even considering the presence of this important risk factor.}, } @article {pmid26891290, year = {2016}, author = {Oprea, AE and Pandel, LM and Dumitrescu, AM and Andronescu, E and Grumezescu, V and Chifiriuc, MC and Mogoantă, L and Bălşeanu, TA and Mogoşanu, GD and Socol, G and Grumezescu, AM and Iordache, F and Maniu, H and Chirea, M and Holban, AM}, title = {Bioactive ZnO Coatings Deposited by MAPLE-An Appropriate Strategy to Produce Efficient Anti-Biofilm Surfaces.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {2}, pages = {}, pmid = {26891290}, issn = {1420-3049}, mesh = {Animals ; Anti-Bacterial Agents/administration & dosage/*chemistry ; Biofilms/drug effects ; Cefepime ; Cephalosporins/chemistry/pharmacology ; Coated Materials, Biocompatible/administration & dosage/*chemistry ; Cyclodextrins/chemistry/pharmacology ; Mice ; Nanostructures/*chemistry ; X-Ray Diffraction ; Zinc Oxide/*chemistry ; }, abstract = {Deposition of bioactive coatings composed of zinc oxide, cyclodextrin and cefepime (ZnO/CD/Cfp) was performed by the Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The obtained nanostructures were characterized by X-ray diffraction, IR microscopy and scanning electron microscopy. The efficient release of cefepime was correlated with an increased anti-biofilm activity of ZnO/CD/Cfp composites. In vitro and in vivo tests have revealed a good biocompatibility of ZnO/CD/Cfp coatings, which recommend them as competitive candidates for the development of antimicrobial surfaces with biomedical applications. The release of the fourth generation cephalosporin Cfp in a biologically active form from the ZnO matrix could help preventing the bacterial adhesion and the subsequent colonization and biofilm development on various surfaces, and thus decreasing the risk of biofilm-related infections.}, } @article {pmid26890680, year = {2016}, author = {Chauhan, A and Ghigo, JM and Beloin, C}, title = {Study of in vivo catheter biofilm infections using pediatric central venous catheter implanted in rat.}, journal = {Nature protocols}, volume = {11}, number = {3}, pages = {525-541}, pmid = {26890680}, issn = {1750-2799}, mesh = {Animals ; *Bacterial Physiological Phenomena ; *Biofilms ; Catheter-Related Infections/*etiology/*microbiology/prevention & control ; Central Venous Catheters/adverse effects/*microbiology ; Cross Infection/etiology/microbiology/prevention & control ; Disease Models, Animal ; Equipment Design ; Luminescent Measurements ; Male ; Optical Imaging ; Rats ; Rats, Wistar ; }, abstract = {Venous access catheters used in clinics are prone to biofilm contamination, contributing to chronic and nosocomial infections. Although several animal models for studying device-associated biofilms were previously described, only a few detailed protocols are currently available. Here we provide a protocol using totally implantable venous access ports (TIVAPs) implanted in rats. This model recapitulates all phenomena observed in the clinic, and it allows bacterial biofilm development and physiology to be studied. After TIVAP implantation and inoculation with luminescent pathogens, in vivo biofilm formation can be monitored in situ, and biofilm biomass can be recovered from contaminated TIVAP and organs. We used this protocol to study host responses to biofilm infection, to evaluate preventive and curative antibiofilm strategies and to study fundamental biofilm properties. For this procedure, one should expect ∼3 h of hands-on time, including the implantation in one rat followed by in situ luminescence monitoring and bacterial load estimation.}, } @article {pmid26891369, year = {2016}, author = {Brackman, G and Garcia-Fernandez, MJ and Lenoir, J and De Meyer, L and Remon, JP and De Beer, T and Concheiro, A and Alvarez-Lorenzo, C and Coenye, T}, title = {Dressings Loaded with Cyclodextrin-Hamamelitannin Complexes Increase Staphylococcus aureus Susceptibility Toward Antibiotics Both in Single as well as in Mixed Biofilm Communities.}, journal = {Macromolecular bioscience}, volume = {16}, number = {6}, pages = {859-869}, doi = {10.1002/mabi.201500437}, pmid = {26891369}, issn = {1616-5195}, mesh = {Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/growth & development ; Cyclodextrins/*chemistry/pharmacology ; Gallic Acid/analogs & derivatives/chemistry/pharmacokinetics ; Hexoses/chemistry/pharmacokinetics ; Humans ; Microbial Sensitivity Tests ; Quorum Sensing/*drug effects ; Staphylococcus aureus/*drug effects/pathogenicity ; Wound Infection/drug therapy/microbiology ; }, abstract = {Bacteria reside within biofilms at the infection site, making them extremely difficult to eradicate with conventional wound care products. Bacteria use quorum sensing (QS) systems to regulate biofilm formation, and QS inhibitors (QSIs) have been proposed as promising antibiofilm agents. Despite this, few antimicrobial therapies that interfere with QS exist. Nontoxic hydroxypropyl-β-cyclodextrin-functionalized cellulose gauzes releasing a burst of the antibiotic vancomycin and the QSI hamamelitannin are developed, followed by a sustained release of both. The gauzes affect QS and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro model of chronic wound infection and can be considered as candidates to be used to prevent wound infection as well as treat infected wounds.}, } @article {pmid26890506, year = {2016}, author = {Hu, H and Johani, K and Almatroudi, A and Vickery, K and Van Natta, B and Kadin, ME and Brody, G and Clemens, M and Cheah, CY and Lade, S and Joshi, PA and Prince, HM and Deva, AK}, title = {Bacterial Biofilm Infection Detected in Breast Implant-Associated Anaplastic Large-Cell Lymphoma.}, journal = {Plastic and reconstructive surgery}, volume = {137}, number = {6}, pages = {1659-1669}, doi = {10.1097/PRS.0000000000002010}, pmid = {26890506}, issn = {1529-4242}, mesh = {Adult ; Aged ; Bacteria/genetics/*isolation & purification ; Bacterial Load ; *Biofilms ; Breast Implants/*microbiology ; DNA, Bacterial/analysis ; Female ; Humans ; In Situ Hybridization, Fluorescence ; Lymphoma, Large-Cell, Anaplastic/diagnosis/*microbiology ; Male ; Mammaplasty/*adverse effects ; Microscopy, Electron, Scanning ; Middle Aged ; Prosthesis-Related Infections/diagnosis/*microbiology ; Real-Time Polymerase Chain Reaction ; }, abstract = {BACKGROUND: A recent association between breast implants and the development of anaplastic large-cell lymphoma (ALCL) has been observed. The purpose of this study was to identify whether bacterial biofilm is present in breast implant-associated ALCL and, if so, to compare the bacterial microbiome to nontumor capsule samples from breast implants with contracture.

METHODS: Twenty-six breast implant-associated ALCL samples were analyzed for the presence of biofilm by real-time quantitative polymerase chain reaction, next-generation sequencing, fluorescent in situ hybridization, and scanning electron microscopy, and compared to 62 nontumor capsule specimens.

RESULTS: Both the breast implant-associated ALCL and nontumor capsule samples yielded high mean numbers of bacteria (breast implant-associated ALCL, 4.7 × 10 cells/mg of tissue; capsule, 4.9 × 10 cells/mg of tissue). Analysis of the microbiome in breast implant-associated ALCL specimens showed significant differences with species identified in nontumor capsule specimens. There was a significantly greater proportion of Ralstonia spp. present in ALCL specimens compared with nontumor capsule specimens (p < 0.05). In contrast, significantly more Staphylococcus spp. were found associated with nontumor capsule specimens compared with breast implant-associated ALCL specimens (p < 0.001). Bacterial biofilm was visualized both on scanning electron microscopy and fluorescent in situ hybridization.

CONCLUSIONS: This novel finding of bacterial biofilm and a distinct microbiome in breast implant-associated ALCL samples points to a possible infectious contributing cause. Breast implants are widely used in both reconstructive and aesthetic surgery, and strategies to reduce their contamination should be more widely studied and practiced.

Risk, V.}, } @article {pmid26887287, year = {2016}, author = {Vannecke, TP and Bernet, N and Winkler, MK and Santa-Catalina, G and Steyer, JP and Volcke, EI}, title = {Influence of process dynamics on the microbial diversity in a nitrifying biofilm reactor: Correlation analysis and simulation study.}, journal = {Biotechnology and bioengineering}, volume = {113}, number = {9}, pages = {1962-1974}, doi = {10.1002/bit.25952}, pmid = {26887287}, issn = {1097-0290}, mesh = {Bacteria/chemistry/*metabolism ; *Biofilms ; Bioreactors/*microbiology ; Computer Simulation ; *Models, Biological ; Nitrification ; Nitrogen/*metabolism ; }, abstract = {For engineers, it is interesting to gain insight in the effect of control strategies on microbial communities, on their turn influencing the process behavior and its stability. This contribution assesses the influence of process dynamics on the microbial community in a biofilm reactor for nitrogen removal, which was controlled according to several strategies aiming at nitrite accumulation. The process dataset, combining conventional chemical and physical data with molecular information, was analyzed through a correlation analysis and in a simulation study. During nitrate formation, an increased nitrogen loading rate (NLR) resulted in a drop of the bulk liquid oxygen concentration without resulting in nitrite accumulation. A biofilm model was able to reproduce the bulk liquid nitrogen concentrations in two periods before and after this increased NLR. As the microbial parameters calibrated for the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in both periods were different, it was concluded that the increased NLR governed an AOB and NOB population shift. Based on the molecular data, it was assumed that each period was typified by one dominant AOB and probably several subdominant NOB populations. The control strategies for nitrite accumulation influenced the bulk liquid composition by controlling the competition between AOB and NOB. Biotechnol. Bioeng. 2016;113: 1962-1974. © 2016 Wiley Periodicals, Inc.}, } @article {pmid26887246, year = {2016}, author = {Faten, K and Hamida, K and Soumya, el A and Saad, IS and Hasna, M and Hassan, L and Moktar, H}, title = {Lactobacillus plantarum: Effect of a protective biofilm on the surface of olives during storage.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {47}, number = {1}, pages = {202-209}, pmid = {26887246}, issn = {1678-4405}, mesh = {*Bacterial Adhesion ; Biofilms/*growth & development ; Electron Transport ; *Food Storage ; Hydrophobic and Hydrophilic Interactions ; Lactobacillus plantarum/*physiology ; Microscopy, Electron, Scanning ; Olea/*microbiology ; Surface Properties ; Yeasts/physiology ; }, abstract = {The aim of the present study was to investigate the effect of Lactobacillus plantarum adhesion to the surface of olives during storage through studying the interaction between the surfaces of the olives and L. plantarum. The results showed that the total number of adherent L. plantarum increased exponentially from 1.2×10(6) to 1.3×10(8)cfu/g. Images obtained using environmental scanning electron microscopy (ESEM) after 4 days of storage revealed that the olive surface was covered with a uniform and compact biofilm constituted of L. plantarum and yeast. Physicochemical analysis of surface of L. plantarum revealed that it was hydrophilic (Giwi>0mJ/m(2)). The surface of the olives also appeared to be hydrophilic (Giwi=3.28mJ/m(2)). The electron-donor characteristics of the surfaces of L. plantarum and olive were γ(-)=53.1mJ/m(2) and γ(-)=28.1mJ/m(2), respectively. The formation of a protective biofilm of L. plantarum increased the hydrophilicity (from 3.28 to 46.14mJ/m(2)) and the electron-donor capacity (from 28.1 to 67.2mJ/m(2)) of the olive surface by 1 day of storage. Analysis of the impact of the biofilm that formed on the surface of the olives during storage showed a reduction in the content of undesirable planktonic microorganisms, such as fungi, which could have occurred due to competition for nutrients and oxygen or modifications in the physicochemical properties of the olives. Thus, coating the surface of olives with a natural material, such as L. plantarum, may be a first step in developing strategies to prevent their microbial colonization.}, } @article {pmid26887226, year = {2016}, author = {Khezri, M and Jouzani, GS and Ahmadzadeh, M}, title = {Fusarium culmorum affects expression of biofilm formation key genes in Bacillus subtilis.}, journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]}, volume = {47}, number = {1}, pages = {47-54}, pmid = {26887226}, issn = {1678-4405}, mesh = {Bacillus subtilis/*physiology ; Biofilms/*growth & development ; Fusarium/*physiology ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial ; *Microbial Interactions ; Real-Time Polymerase Chain Reaction ; }, abstract = {It is known that there is correlation between biofilm formation and antagonistic activities of Bacillus subtilis strains; but, the mechanism of this correlation is not clear. So, the effect of the plant pathogen (Fusarium culmorum) on the biofilm formation in a B. subtilis strain with high antagonistic and biofilm formation activities was studied. The expression of sinR and tasA genes involved in the biofilm formation was studied in both single culture of bacterium (B) and co-culture with F. culmorum (FB) using real-time PCR. The results revealed that the expression of the sinR gene in both B and FB conditions was continuously decreased during the biofilm formation period and, after 24h (B4 and FB4), it reached 1% and 0.3% at the planktonic phase (B1), respectively, whereas the expression of the tasA was continuously increased and was 5.27 and 30 times more than that at the planktonic phase (B1) after 24h, respectively. So, the expression reduction rate for sinR (3 times) and the expression increasing rate for tasA (6 times) were significantly higher in FB conditions than the B ones. The relative expression of sinR in FB1 (planktonic phase), FB2 (8h), FB3(12h), and FB4 (24h) times was 0.65, 0.44, 0.35, and 0.29, whereas the tasA gene expression was 2.98, 3.44, 4.37, and 5.63-fold of the one at coordinate time points in B conditions, respectively. The significant expression reduction of sinR and increase of tasA confirmed that the presence of pathogen could stimulate biofilm formation in the antagonistic bacterium.}, } @article {pmid26885364, year = {2016}, author = {Neupane, S and Pant, ND and Khatiwada, S and Chaudhary, R and Banjara, MR}, title = {Correlation between biofilm formation and resistance toward different commonly used antibiotics along with extended spectrum beta lactamase production in uropathogenic Escherichia coli isolated from the patients suspected of urinary tract infections visiting Shree Birendra Hospital, Chhauni, Kathmandu, Nepal.}, journal = {Antimicrobial resistance and infection control}, volume = {5}, number = {}, pages = {5}, pmid = {26885364}, issn = {2047-2994}, abstract = {BACKGROUND: Escherichia coli is the most predominant causative agent of urinary tract infection (UTI). Recently, increase in drug resistance among the uropathogenic bacteria has caused great problem in treatment of UTI. The main objective of this research is to determine the correlation between biofilm formation and resistance toward different commonly used antibiotics along with extended spectrum beta lactamase production in uropathogenic Escherichia coli.

METHODS: The urine samples collected from the patients suspected of urinary tract infections (visiting Shree Birendra Hospital, Chhauni, Kathmandu, Nepal between July to December 2013) were cultured in cystine lactose electrolyte deficient (CLED) agar by using semi quantitative culture technique. Extended spectrum beta lactamase (ESBL) production was detected by combined disc diffusion technique and biofilm formation was detected by Congo red agar method. Chi-square test was applied and p-value < 0.05 was considered statistically significant.

RESULTS: Out of 1480 urine samples, E. Coli was isolated from 208 (14.1 %) samples. Of total 69 (33.2 %) ESBL producing uropathogenic strains of E. coli, 20 (29 %) were strong biofilm producers, 22 (31.9 %) were moderate biofilm producers, 11 (15.9 %) were weak biofilm producers and 16 (23.2 %) were biofilm non producers. Whereas among 139 ESBL non producing E. coli, 22 (15.8 %) were strong biofilm producers, 20 (14.4 %) were moderate biofilm producers, 13 (9.4 %) were weak biofilm producers and 84 (60.4 %) were biofilm non producers. Among total 108 biofilm producing E. coli, maximum resistance was observed toward cephalexin followed by amoxicillin and highest susceptibility was seen toward amikacin.

CONCLUSION: The ability of biofilm formation was found to be significantly higher in ESBL producing strains of E. coli than that in ESBL non producing strains (p < 0.05). There was higher resistance rate to antimicrobial agents among biofilm producing strains of E. coli than that in biofilm non producing strains. According to our antimicrobial susceptibility pattern for E. coli, to start preliminary treatment for UTI in Nepal, we recommend to use amikacin or nitrofurantoin. Further, for the treatment of the UTI, the antibiotics should be selected on the basis of the urine culture and sensitivity report.}, } @article {pmid26884812, year = {2016}, author = {Gross, M and Zhao, X and Mascarenhas, V and Wen, Z}, title = {Effects of the surface physico-chemical properties and the surface textures on the initial colonization and the attached growth in algal biofilm.}, journal = {Biotechnology for biofuels}, volume = {9}, number = {}, pages = {38}, pmid = {26884812}, issn = {1754-6834}, abstract = {BACKGROUND: Algal biofilm reactors represent a promising cultivation system that can economically produce biomass without the need for expensive harvesting operations. A critical component of algal biofilm systems is the material used for attachment. This research reports a comprehensive study of the effects of material surface physico-chemical properties, the surface texture, and their interactions on the initial colonization and the long-term attached growth in algal biofilm systems. A total of 28 materials with a smooth surface were tested for initial cell colonization and it was found that the tetradecane contact angle of the materials had a good correlation with cell attachment. The effects of surface texture were evaluated using mesh materials (nylon, polypropylene, high-density polyethylene, polyester, aluminum, and stainless steel) with openings ranging from 0.05 to 6.40 mm.

RESULTS: The mesh materials with an opening of 0.5 mm resulted in the highest attachment. The interaction of surface physico-chemical properties and surface texture, and their co-effects on the cell attachment, was quantitatively described using a second-order polynomial regression. The long-term algal attached growth for the different materials showed a trend similar to that found in initial colonization.

CONCLUSIONS: Collectively, nylon and polypropylene mesh with 0.50-1.25 mm openings resulted in the best initial colonization and long-term attached growth, with a 28-30 g m(-2) biomass yield and 4.0-4.3 g m(-2) day biomass productivity being achieved on a pilot-scale revolving algal biofilm system.}, } @article {pmid26884212, year = {2016}, author = {Jang, IA and Kim, J and Park, W}, title = {Endogenous hydrogen peroxide increases biofilm formation by inducing exopolysaccharide production in Acinetobacter oleivorans DR1.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {21121}, pmid = {26884212}, issn = {2045-2322}, mesh = {Acinetobacter/*physiology ; Antioxidants/metabolism ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Hydrogen Peroxide/*metabolism ; Mutation ; Oxidative Stress ; Polysaccharides, Bacterial/*biosynthesis ; Transcription, Genetic ; }, abstract = {In this study, we investigated differentially expressed proteins in Acinetobacter oleivorans cells during planktonic and biofilm growth by using 2-dimensional gel electrophoresis combined with matrix-assisted laser desorption time-of-flight mass spectrometry. We focused on the role of oxidative stress resistance during biofilm formation using mutants defective in alkyl hydroperoxide reductase (AhpC) because its production in aged biofilms was enhanced compared to that in planktonic cells. Results obtained using an ahpC promoter-gfp reporter vector showed that aged biofilms expressed higher ahpC levels than planktonic cells at 48 h. However, at 24 h, ahpC expression was higher in planktonic cells than in biofilms. Deletion of ahpC led to a severe growth defect in rich media that was not observed in minimal media and promoted early biofilm formation through increased production of exopolysaccharide (EPS) and EPS gene expression. Increased endogenous H2O2 production in the ahpC mutant in rich media enhanced biofilm formation, and this enhancement was not observed in the presence of antioxidants. Exogenous addition of H2O2 promoted biofilm formation in wild type cells, which suggested that biofilm development is linked to defense against H2O2. Collectively, our data showed that EPS production caused by H2O2 stress enhances biofilm formation in A. oleivorans.}, } @article {pmid26883809, year = {2016}, author = {Zhou, C and Ontiveros-Valencia, A and Wang, Z and Maldonado, J and Zhao, HP and Krajmalnik-Brown, R and Rittmann, BE}, title = {Palladium Recovery in a H2-Based Membrane Biofilm Reactor: Formation of Pd(0) Nanoparticles through Enzymatic and Autocatalytic Reductions.}, journal = {Environmental science & technology}, volume = {50}, number = {5}, pages = {2546-2555}, doi = {10.1021/acs.est.5b05318}, pmid = {26883809}, issn = {1520-5851}, mesh = {Betaproteobacteria/metabolism ; Biofilms ; Bioreactors/*microbiology ; Denitrification ; Equipment Design ; Hydrogen-Ion Concentration ; Microbial Consortia/physiology ; Nanoparticles/*chemistry ; Oxidation-Reduction ; Palladium/chemistry/*isolation & purification ; Rhodocyclaceae/metabolism ; Waste Management/instrumentation/*methods ; }, abstract = {Recovering palladium (Pd) from waste streams opens up the possibility of augmenting the supply of this important catalyst. We evaluated Pd reduction and recovery as a novel application of a H2-based membrane biofilm reactor (MBfR). At steady states, over 99% of the input soluble Pd(II) was reduced through concomitant enzymatic and autocatalytic processes at acidic or near neutral pHs. Nanoparticulate Pd(0), at an average crystallite size of 10 nm, was recovered with minimal leaching and heterogeneously associated with microbial cells and extracellular polymeric substances in the biofilm. The dominant phylotypes potentially responsible for Pd(II) reduction at circumneutral pH were denitrifying β-proteobacteria mainly consisting of the family Rhodocyclaceae. Though greatly shifted by acidic pH, the biofilm microbial community largely bounced back when the pH was returned to 7 within 2 weeks. These discoveries infer that the biofilm was capable of rapid adaptive evolution to stressed environmental change, and facilitated Pd recovery in versatile ways. This study demonstrates the promise of effective microbially driven Pd recovery in a single MBfR system that could be applied for the treatment of the waste streams, and it documents the role of biofilms in this reduction and recovery process.}, } @article {pmid26883392, year = {2016}, author = {Kifer, D and Mužinić, V and Klarić, MŠ}, title = {Antimicrobial potency of single and combined mupirocin and monoterpenes, thymol, menthol and 1,8-cineole against Staphylococcus aureus planktonic and biofilm growth.}, journal = {The Journal of antibiotics}, volume = {69}, number = {9}, pages = {689-696}, pmid = {26883392}, issn = {1881-1469}, mesh = {Anti-Bacterial Agents/administration & dosage/*pharmacology ; Biofilms/*drug effects ; Cyclohexanols/administration & dosage/*pharmacology ; Drug Synergism ; Eucalyptol ; Menthol/administration & dosage/pharmacology ; Methicillin-Resistant Staphylococcus aureus/drug effects ; Microbial Sensitivity Tests ; Monoterpenes/administration & dosage/*pharmacology ; Mupirocin/administration & dosage/*pharmacology ; Plankton/drug effects ; Staphylococcus aureus/*drug effects ; Thymol/administration & dosage/pharmacology ; }, abstract = {Staphylococcus aureus is one of the most commonly isolated microbes in chronic rhinosinusitis (CRS) that can be complicated due to the formation of a staphylococcal biofilm. In this study, we investigated antimicrobial efficacy of single mupirocin and three types of monoterpenes (thymol, menthol and 1,8-cineole) as well as mupirocin-monoterpene combinations against S. aureus ATCC 29213 and 5 methicilin-resistant S. aureus strains (MRSA) grown in planktonic and biofilm form. MIC against planktonic bacteria as well as minimum biofilm-eliminating concentrations (MBECs) and minimum biofilm inhibitory concentrations (MBICs) were determined by TTC and MTT reduction assay, respectively. The MICs of mupirocin (0.125-0.156 μg ml(-1)) were three orders of magnitude lower than the MICs of monoterpenes, which were as follows: thymol (0.250-0.375 mg ml(-1)) > menthol (1 mg ml(-1)) > 1,8-cineole (4-8 mg ml(-1)). Mupirocin-monoterpene combinations showed indifferent effect as compared with MICs of single substances. Mupirocin (0.016-2 mg ml(-1)) failed to destroy the biofilm. The MBECs of thymol and menthol were two- to sixfold higher than their MICs, while 1,8-cineole exerted a weak antibiofilm effect with MBECs 16- to 64-fold higher than MICs. Mixture of mupirocin and 1,8 cineole exerted a potentiated biofilm-eliminating effect, mupirocin-menthol showed antagonism, while effect of thymol-mupirocin mixture was inconclusive. MBICs of antimicrobials were close to their MICs, except 1,8-cineole, MBIC was about three- to fivefold higher. Dominant synergy was observed for mixtures of mupirocin and menthol or thymol, whereas mupirocin-1,8-cineol exerted an indifferent or additive biofilm inhibitory effect. Particular combinations of mupirocin and the monoterpenes could be applied in CRS therapy in order to eliminate or prevent bacterial biofilm growth.}, } @article {pmid26882175, year = {2016}, author = {Ritenberg, M and Nandi, S and Kolusheva, S and Dandela, R and Meijler, MM and Jelinek, R}, title = {Imaging Pseudomonas aeruginosa Biofilm Extracellular Polymer Scaffolds with Amphiphilic Carbon Dots.}, journal = {ACS chemical biology}, volume = {11}, number = {5}, pages = {1265-1270}, doi = {10.1021/acschembio.5b01000}, pmid = {26882175}, issn = {1554-8937}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/drug effects/*growth & development ; Carbon/*chemistry ; Fluorescent Dyes/*chemistry ; Humans ; Microscopy, Fluorescence/methods ; Optical Imaging/*methods ; Pseudomonas Infections/drug therapy/*microbiology ; Pseudomonas aeruginosa/drug effects/growth & development/*physiology ; Quorum Sensing/drug effects ; Surface-Active Agents/*chemistry ; }, abstract = {Biofilm formation is a critical facet of pathogenesis and resilience of human, animal, and plant bacteria. Extracellular polymeric substances (EPS) constitute the physical scaffolding for bacterial biofilms and thus play central roles in their development and virulence. We show that newly synthesized amphiphilic fluorescent carbon dots (C-dots) readily bind to the EPS scaffold of Pseudomonas aeruginosa, a major biofilm-forming pathogen, resulting in unprecedented microscopic visualization of the EPS structural features. Fluorescence microscopy analysis utilizing the C-dots reveals that the P. aeruginosa EPS matrix exhibits a remarkable dendritic morphology. The experiments further illuminate the growth kinetics of the EPS and the effect of external factors such as temperature. We also show that the amphiphilic C-dot platform enabled screening of substances disrupting biofilm development, specifically quorum sensing inhibitors.}, } @article {pmid26881198, year = {2015}, author = {Bennani, V and Hwang, L and Tawse-Smith, A and Dias, GJ and Cannon, RD}, title = {Effect of Air-Polishing on Titanium Surfaces, Biofilm Removal, and Biocompatibility: A Pilot Study.}, journal = {BioMed research international}, volume = {2015}, number = {}, pages = {491047}, pmid = {26881198}, issn = {2314-6141}, mesh = {Animals ; *Biofilms ; Cell Line ; Cell Survival/drug effects ; Glycine/*chemistry/toxicity ; Materials Testing ; Mice ; Pilot Projects ; Surface Properties ; Titanium/*chemistry ; }, abstract = {PURPOSE: The aims of this in vitro study were to evaluate morphological changes induced by glycine powder air-polishing on titanium surfaces, biofilm removal, and biocompatibility.

MATERIAL AND METHODS: Titanium grade IV discs were allocated into two groups: (1) discs without biofilm and (2) discs for Streptococcus mutans biofilm formation. Discs in each group were further subdivided into (a) no treatment and (b) air-polishing treatment with glycine powder. Discs were characterized by scanning electron microscopy (SEM), electron-dispersive spectroscopy (EDS), and confocal microscopy. Bacterial biofilms were quantified using a crystal violet dye-binding assay. Biocompatibility was evaluated by measuring the coverage and viability of L929 fibroblast cells cultured on the discs.

RESULTS: Air-polishing increased the roughness of treated discs (P < 0.05). EDS analysis did not show significant differences in the chemical composition of treated and nontreated discs. The amount of residual biofilm on treated discs was 8.6-fold lower than untreated controls (P < 0.05). Coverage of treated discs by fibroblasts was half that of untreated discs (P < 0.05) although both groups had the same cell viability.

CONCLUSIONS: Air-polishing removed a significant amount of biofilm from titanium surfaces. The "polishing" was accompanied by increased surface roughness, but there were no changes in chemical and elemental compositions, nor the biocompatibility.}, } @article {pmid26880544, year = {2016}, author = {Desai, SK and Winardhi, RS and Periasamy, S and Dykas, MM and Jie, Y and Kenney, LJ}, title = {The horizontally-acquired response regulator SsrB drives a Salmonella lifestyle switch by relieving biofilm silencing.}, journal = {eLife}, volume = {5}, number = {}, pages = {}, pmid = {26880544}, issn = {2050-084X}, support = {I01 BX000372/BX/BLRD VA/United States ; }, mesh = {Bacterial Proteins/*metabolism ; Biofilms/*growth & development ; *Gene Expression Regulation, Bacterial ; Genomic Islands ; Salmonella typhimurium/*genetics/*physiology ; Transcription Factors/*metabolism ; }, abstract = {A common strategy by which bacterial pathogens reside in humans is by shifting from a virulent lifestyle, (systemic infection), to a dormant carrier state. Two major serovars of Salmonella enterica, Typhi and Typhimurium, have evolved a two-component regulatory system to exist inside Salmonella-containing vacuoles in the macrophage, as well as to persist as asymptomatic biofilms in the gallbladder. Here we present evidence that SsrB, a transcriptional regulator encoded on the SPI-2 pathogenicity-island, determines the switch between these two lifestyles by controlling ancestral and horizontally-acquired genes. In the acidic macrophage vacuole, the kinase SsrA phosphorylates SsrB, and SsrB~P relieves silencing of virulence genes and activates their transcription. In the absence of SsrA, unphosphorylated SsrB directs transcription of factors required for biofilm formation specifically by activating csgD (agfD), the master biofilm regulator by disrupting the silenced, H-NS-bound promoter. Anti-silencing mechanisms thus control the switch between opposing lifestyles.}, } @article {pmid26880271, year = {2016}, author = {Park, SR and Tripathi, A and Wu, J and Schultz, PJ and Yim, I and McQuade, TJ and Yu, F and Arevang, CJ and Mensah, AY and Tamayo-Castillo, G and Xi, C and Sherman, DH}, title = {Discovery of cahuitamycins as biofilm inhibitors derived from a convergent biosynthetic pathway.}, journal = {Nature communications}, volume = {7}, number = {}, pages = {10710}, pmid = {26880271}, issn = {2041-1723}, support = {U54 AI57153/AI/NIAID NIH HHS/United States ; U01 TW007404/TW/FIC NIH HHS/United States ; R01 GM098350/GM/NIGMS NIH HHS/United States ; 1R01GM098350/GM/NIGMS NIH HHS/United States ; U54 AI057153/AI/NIAID NIH HHS/United States ; }, mesh = {Acinetobacter baumannii/*drug effects/physiology ; Anti-Bacterial Agents/biosynthesis/*pharmacology ; Bacterial Proteins/biosynthesis/*pharmacology ; Biofilms/*drug effects ; Biosynthetic Pathways ; High-Throughput Screening Assays ; Oligopeptides/biosynthesis/*pharmacology ; Streptomyces ; }, abstract = {Pathogenic microorganisms often have the ability to attach to a surface, building a complex matrix where they colonize to form a biofilm. This cellular superstructure can display increased resistance to antibiotics and cause serious, persistent health problems in humans. Here we describe a high-throughput in vitro screen to identify inhibitors of Acinetobacter baumannii biofilms using a library of natural product extracts derived from marine microbes. Analysis of extracts derived from Streptomyces gandocaensis results in the discovery of three peptidic metabolites (cahuitamycins A-C), with cahuitamycin C being the most effective inhibitor (IC50=14.5 μM). Biosynthesis of cahuitamycin C proceeds via a convergent biosynthetic pathway, with one of the steps apparently being catalysed by an unlinked gene encoding a 6-methylsalicylate synthase. Efforts to assess starter unit diversification through selective mutasynthesis lead to production of unnatural analogues cahuitamycins D and E of increased potency (IC50=8.4 and 10.5 μM).}, } @article {pmid26879980, year = {2016}, author = {Gerrity, S and Clifford, E and Kennelly, C and Collins, G}, title = {Ammonia oxidizing bacteria and archaea in horizontal flow biofilm reactors treating ammonia-contaminated air at 10 °C.}, journal = {Journal of industrial microbiology & biotechnology}, volume = {43}, number = {5}, pages = {651-661}, pmid = {26879980}, issn = {1476-5535}, mesh = {Air/*analysis ; Ammonia/*isolation & purification/*metabolism ; Archaea/*metabolism ; Bacteria/*metabolism ; *Biofilms ; *Bioreactors ; Feasibility Studies ; Nitrates/metabolism ; *Nitrification ; Nitrites/metabolism ; Oxidation-Reduction ; *Temperature ; }, abstract = {The objective of this study was to demonstrate the feasibility of novel, Horizontal Flow Biofilm Reactor (HFBR) technology for the treatment of ammonia (NH3)-contaminated airstreams. Three laboratory-scale HFBRs were used for remediation of an NH3-containing airstream at 10 °C during a 90-d trial to test the efficacy of low-temperature treatment. Average ammonia removal efficiencies of 99.7 % were achieved at maximum loading rates of 4.8 g NH3 m(3) h(-1). Biological nitrification of ammonia to nitrite (NO2 (-)) and nitrate (NO3 (-)) was mediated by nitrifying bacterial and archaeal biofilm populations. Ammonia-oxidising bacteria (AOB) were significantly more abundant than ammonia-oxidising archaea (AOA) vertically at each of seven sampling zones along the vertical HFBRs. Nitrosomonas and Nitrosospira, were the two most dominant bacterial genera detected in the HFBRs, while an uncultured archaeal clone dominated the AOA community. The bacterial community composition across the three HFBRs was highly conserved, although variations occurred between HFBR zones and were driven by physicochemical variables. The study demonstrates the feasibility of HFBRs for the treatment of ammonia-contaminated airstreams at low temperatures; identifies key nitrifying microorganisms driving the removal process; and provides insights for process optimisation and control. The findings are significant for industrial applications of gas oxidation technology in temperate climates.}, } @article {pmid26878370, year = {2016}, author = {Snow, DE and Everett, J and Mayer, G and Cox, SB and Miller, B and Rumbaugh, K and Wolcott, RA and Wolcott, RD}, title = {The presence of biofilm structures in atherosclerotic plaques of arteries from legs amputated as a complication of diabetic foot ulcers.}, journal = {Journal of wound care}, volume = {25}, number = {2}, pages = {S16-22}, doi = {10.12968/jowc.2016.25.Sup2.S16}, pmid = {26878370}, issn = {0969-0700}, mesh = {Adult ; Aged ; Amputation, Surgical ; Arteries/ultrastructure ; Atherosclerosis/*etiology/*microbiology ; *Biofilms ; Diabetic Foot/*complications ; Humans ; Inflammation/*etiology/*microbiology ; Male ; Middle Aged ; Plaque, Atherosclerotic/*microbiology ; Risk Factors ; }, abstract = {OBJECTIVE: Atherosclerosis, rather than microcirculatory impairment caused by endothelial cell dysfunction, is the main driver of circulatory compromise in patients with diabetic limbs. The presence of atherosclerotic plaque at the trifurcation is a significant contributor to amputation of diabetic legs. The presence of bacteria and other microorganisms in atherosclerotic plaque has long been known, however, the cause of chronic inflammation and the role of bacteria/viruses in atherosclerosis have not been studied in detail. The objective of this study was to clarify the cause of the chronic inflammation within atherosclerotic plaques, and determine if any bacteria and/or viruses are involved in the inflammatory pathway.

METHOD: This study uses fluorescence microscopy and fluorescence in-situ hybridisation (FISH) to identify components of biofilm in atherosclerotic arteries. These tools are also used to identify individual bacteria, and determine the architectural spatial location within the atherosclerotic plaque where the bacteria can be found.

RESULTS: The results indicate that the presence of biofilms in grossly involved arteries may be an important factor in chronic inflammatory pathways of atherosclerotic progression, in the amputated limbs of patients with diabetic foot ulcers and vascular disease.

CONCLUSION: While the presence of bacterial biofilm structures in atherosclerotic plaque does not prove that biofilm is the proximate cause of atherosclerosis, it could contribute to the persistent inflammation associated with it. Second, the synergistic relationship between the atherosclerotic infection and the diabetic foot ulcer may ultimately contribute to higher amputation rates in diabetics.

DECLARATION OF INTEREST: RAW and RDW have equity interest in PathoGenius, a clinical laboratory using DNA to identify microbes.}, } @article {pmid26878302, year = {2016}, author = {Halstead, FD and Webber, MA and Rauf, M and Burt, R and Dryden, M and Oppenheim, BA}, title = {In vitro activity of an engineered honey, medical-grade honeys, and antimicrobial wound dressings against biofilm-producing clinical bacterial isolates.}, journal = {Journal of wound care}, volume = {25}, number = {2}, pages = {93-4, 96-102}, doi = {10.12968/jowc.2016.25.2.93}, pmid = {26878302}, issn = {0969-0700}, mesh = {Acinetobacter baumannii/drug effects ; Anti-Bacterial Agents/*pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cells, Cultured/*drug effects ; Escherichia coli/drug effects ; *Honey ; Humans ; Klebsiella pneumoniae/drug effects ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects ; Staphylococcus aureus/drug effects ; }, abstract = {OBJECTIVE: Honey is recognised to be a good topical wound care agent owing to a broad-spectrum of antimicrobial activity combined with healing properties. Surgihoney RO (SH1) is a product based on honey that is engineered to produce enhanced reactive oxygen species (ROS) and has been reported to be highly antimicrobial. The objective was to investigate the ability of the engineered honey and its comparators to prevent biofilm formation in vitro.

METHOD: We tested the ability of three medical-grade honeys SH1, Activon manuka honey (MH) and Medihoney manuka honey (Med), alongside five antimicrobial dressings (AMDs) to prevent the formation of biofilms by 16 isolates. Honeys were serially double diluted from 1:3 down to 1:6144 and the lowest dilution achieving a statistically significant reduction in biomass of at least 50%, compared with untreated controls, was recorded.

RESULTS: Although all the honeys were antibacterial and were able to prevent the formation of biofilms, SH1 was the most potent, with efficacy at lower dilutions than the medical honeys for five isolates, and equivalent dilutions for a further six. Additionally, SH1 was superior in antibacterial potency to three commercially available AMDs that contain honey.

CONCLUSION: SH1 is effective at preventing bioflms from forming and is superior to medical honeys and AMDs in in vitro tests.

DECLARATION OF INTEREST: Surgihoney RO was provided free of charge for testing by Matoke Holdings, UK and the hospital pharmacy provided the other honeys and dressings. This paper presents independent research funded by the National Institute for Health Research (NIHR). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.}, } @article {pmid26877035, year = {2016}, author = {Deng, Y and Zhang, X and Miao, Y and Hu, B}, title = {Exploration of rapid start-up of the CANON process from activated sludge inoculum in a sequencing biofilm batch reactor (SBBR).}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {3}, pages = {535-542}, doi = {10.2166/wst.2015.518}, pmid = {26877035}, issn = {0273-1223}, mesh = {Aerobiosis ; Anaerobiosis ; Autotrophic Processes ; Bacteria/classification/genetics/isolation & purification ; *Bacterial Physiological Phenomena ; Biofilms/*growth & development ; Bioreactors ; Nitrification ; Nitrites/*metabolism ; Nitrogen/*metabolism ; Sewage/analysis ; Water Pollutants, Chemical/*metabolism ; }, abstract = {In this study, a laboratory-scale sequencing biofilm batch reactor (SBBR) was employed to explore a fast start-up of completely autotrophic nitrogen removal over nitrite (CANON) process. Partial nitrification was achieved by controlling free ammonia concentration and operating at above 30 °C; then the reactor was immediately operated with alternating periods of aerobiosis and anaerobiosis to start the anammox process. The CANON process was successfully achieved in less than 50 d, and the total-nitrogen removal efficiency and the nitrogen removal rate were 81% and 0.14 kg-N m(-3) d(-1) respectively. Afterwards, with the increasing of ammonium loading rate a maximum nitrogen removal rate of 0.39 kg-N m(-3) d(-1) was achieved on day 94. DNA analysis showed that 'Candidatus Brocadia' was the dominant anammox species and Nitrosomonas was the dominant aerobic ammonium-oxidizing bacteria in the CANON reactor. This study revealed that due to shortening the persistent and stable nitrite accumulation period the long start-up time of the CANON process can be significantly reduced.}, } @article {pmid26875614, year = {2016}, author = {Chau, NP and Pandit, S and Jung, JE and Cai, JN and Yi, HK and Jeon, JG}, title = {Long-term anti-cariogenic biofilm activity of glass ionomers related to fluoride release.}, journal = {Journal of dentistry}, volume = {47}, number = {}, pages = {34-40}, doi = {10.1016/j.jdent.2016.02.006}, pmid = {26875614}, issn = {1879-176X}, mesh = {Acrylic Resins/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Cariostatic Agents/chemistry/*pharmacology ; Fluorides/chemistry/*pharmacology ; Hydrogen-Ion Concentration ; Polysaccharides, Bacterial ; Silicon Dioxide/chemistry/*pharmacology ; Streptococcus mutans/drug effects/metabolism/physiology ; }, abstract = {OBJECTIVES: The aim of this study was to evaluate the difference between anti-cariogenic biofilm activities of glass ionomers (G-Is) during the initial and second fluoride release phases and to define relationships between the anti-biofilm activities and fluoride release.

METHODS: Fluoride release of three commercially available G-Is in a buffer was evaluated for 770 h, and then 70-h-old Streptococcus mutans UA159 biofilms were formed on the G-Is that had been immersed in the buffer for 0, 100, 200, or 700 h. The dry weight, bacterial cell number, water-insoluble extracellular polysaccharides (EPSs), and accumulated fluoride concentration of the 70-h-old biofilms and fluoride release and acid production rates during biofilm formation were determined. Relationships between the experimental variables and fluoride release rate were also evaluated using linear regression analysis.

RESULTS: In this study, fluoride release of the tested G-Is did not exhibit a biphasic pattern during biofilm formation. The release was sustained or did not rapidly decrease even over long immersion periods and was strongly correlated with an increase in accumulated fluoride concentration of the biofilms (R=0.99, R(2)=0.98) and reductions in dry weight, water-insoluble EPSs, and acid production rate of the biofilms (R=-0.99 to -0.96, R(2)=0.92-0.98).

CONCLUSIONS: This study suggests that G-Is can effectively affect acid production, EPS formation, and accumulation of cariogenic biofilms even during the second fluoride release phase, and that the anti-cariogenic biofilm activity is strongly correlated with fluoride release, which may be enhanced by acid production of cariogenic biofilms.

CLINICAL SIGNIFICANCE: G-Is can affect cariogenic biofilm formation even during the second fluoride release phase.}, } @article {pmid26874609, year = {2016}, author = {Nerenberg, R}, title = {The membrane-biofilm reactor (MBfR) as a counter-diffusional biofilm process.}, journal = {Current opinion in biotechnology}, volume = {38}, number = {}, pages = {131-136}, doi = {10.1016/j.copbio.2016.01.015}, pmid = {26874609}, issn = {1879-0429}, mesh = {*Biofilms ; *Bioreactors ; Diffusion ; Hydrogen/metabolism ; Methane/metabolism ; Wastewater/chemistry ; }, abstract = {The membrane-biofilm reactor (MBfR), sometimes known as the membrane-aerated biofilm reactor (MABR), is an emerging treatment technology based on gas-transferring membranes. The membranes typically supply a gaseous electron donor or acceptor substrate, such as oxygen, hydrogen, and methane. The substrate diffuses through the membrane to a biofilm naturally forming on the membrane outer surface. The complementary substrate (electron donor or acceptor) typically diffuses from the bulk liquid into the biofilm, making MBfR counter diffusional. This paper reviews the unique behavior of counter-diffusional biofilms and highlights recent research on the MBfR. Key advances include insights into the microbial community structure of MBfRs, applying the MBfR to novel contaminants, providing a better understanding of biofilm morphology and its effects on MBfR behavior, and the development of methane-based MBfR applications. These advances are likely to further the development of the MBfR for environmental applications, such as energy-efficient wastewater treatment and advanced water treatment.}, } @article {pmid26873318, year = {2016}, author = {Zheng, L and Wang, FF and Ren, BZ and Liu, W and Liu, Z and Qian, W}, title = {Systematic Mutational Analysis of Histidine Kinase Genes in the Nosocomial Pathogen Stenotrophomonas maltophilia Identifies BfmAK System Control of Biofilm Development.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {8}, pages = {2444-2456}, pmid = {26873318}, issn = {1098-5336}, mesh = {Biofilms/*growth & development ; DNA Mutational Analysis ; Gene Expression Regulation, Bacterial ; Histidine Kinase/genetics/*metabolism ; Locomotion ; Mutagenesis, Insertional ; Promoter Regions, Genetic ; Protein Binding ; Stenotrophomonas maltophilia/*enzymology/genetics/*physiology ; Transcription Factors/genetics/metabolism ; }, abstract = {The Gram-negative bacterium Stenotrophomonas maltophilialives in diverse ecological niches. As a result of its formidable capabilities of forming biofilm and its resistance to multiple antibiotic agents, the bacterium is also a nosocomial pathogen of serious threat to the health of patients whose immune systems are suppressed or compromised. Besides the histidine kinase RpfC, the two-component signal transduction system (TCS), which is the canonical regulatory machinery used by most bacterial pathogens, has never been experimentally investigated inS. maltophilia Here, we annotated 62 putative histidine kinase genes in the S. maltophilia genome and successfully obtained 51 mutants by systematical insertional inactivation. Phenotypic characterization identified a series of mutants with deficiencies in bacterial growth, swimming motility, and biofilm development. A TCS, named here BfmA-BfmK (Smlt4209-Smlt4208), was genetically confirmed to regulate biofilm formation inS. maltophilia Together with interacting partner prediction and chromatin immunoprecipitation screens, six candidate promoter regions bound by BfmA in vivo were identified. We demonstrated that, among them, BfmA acts as a transcription factor that binds directly to the promoter regions of bfmA-bfmK and Smlt0800(acoT), a gene encoding an acyl coenzyme A thioesterase that is associated with biofilm development, and positively controls their transcription. Genome-scale mutational analyses of histidine kinase genes and functional dissection of BfmK-BfmA regulation in biofilm provide genetic information to support more in-depth studies on cellular signaling inS. maltophilia, in the context of developing novel approaches to fight this important bacterial pathogen.}, } @article {pmid26872343, year = {2016}, author = {Rafiq, Z and Sam, N and Vaidyanathan, R}, title = {Whole genome sequence of Klebsiella pneumoniae U25, a hypermucoviscous, multidrug resistant, biofilm producing isolate from India.}, journal = {Memorias do Instituto Oswaldo Cruz}, volume = {111}, number = {2}, pages = {144-146}, pmid = {26872343}, issn = {1678-8060}, mesh = {Bacterial Proteins/genetics ; *Biofilms ; Clustered Regularly Interspaced Short Palindromic Repeats/genetics ; Databases, Genetic ; Drug Resistance, Multiple, Bacterial/*genetics ; Genome, Bacterial/*genetics ; Genotyping Techniques/*methods ; Humans ; India ; Klebsiella Infections/*urine ; Klebsiella pneumoniae/classification/*genetics/physiology ; Sequence Analysis, DNA ; beta-Lactamases/genetics ; }, abstract = {Klebsiella pneumoniae U25 is a multidrug resistant strain isolated from a tertiary care hospital in Chennai, India. Here, we report the complete annotated genome sequence of strain U25 obtained using PacBio RSII. This is the first report of the whole genome of K. pneumoniaespecies from Chennai. It consists of a single circular chromosome of size 5,491,870-bp and two plasmids of size 211,813 and 172,619-bp. The genes associated with multidrug resistance were identified. The chromosome of U25 was found to have eight antibiotic resistant genes [blaOXA-1,blaSHV-28, aac(6')1b-cr,catB3, oqxAB, dfrA1]. The plasmid pMGRU25-001 was found to have only one resistant gene (catA1) while plasmid pMGRU25-002 had 20 resistant genes [strAB, aadA1,aac(6')-Ib, aac(3)-IId,sul1,2, blaTEM-1A,1B,blaOXA-9, blaCTX-M-15,blaSHV-11, cmlA1, erm(B),mph(A)]. A mutation in the porin OmpK36 was identified which is likely to be associated with the intermediate resistance to carbapenems in the absence of carbapenemase genes. U25 is one of the few K. pneumoniaestrains to harbour clustered regularly interspaced short palindromic repeats (CRISPR) systems. Two CRISPR arrays corresponding to Cas3 family helicase were identified in the genome. When compared to K. pneumoniaeNTUHK2044, a transposase gene InsH of IS5-13 was found inserted.}, } @article {pmid26871983, year = {2016}, author = {Cardoso, JG and Iorio, NL and Rodrigues, LF and Couri, ML and Farah, A and Maia, LC and Antonio, AG}, title = {Influence of a Brazilian wild green propolis on the enamel mineral loss and Streptococcus mutans' count in dental biofilm.}, journal = {Archives of oral biology}, volume = {65}, number = {}, pages = {77-81}, doi = {10.1016/j.archoralbio.2016.02.001}, pmid = {26871983}, issn = {1879-1506}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Load/drug effects ; Bees ; Biofilms/*drug effects/growth & development ; Cattle ; Cells, Cultured ; Chlorhexidine/pharmacology ; Coumaric Acids/chemistry ; Dental Caries/prevention & control ; Dental Enamel/chemistry/*drug effects ; Hardness/drug effects ; Hydrogen-Ion Concentration ; Incisor/chemistry/drug effects/microbiology ; Propolis/chemistry/*pharmacology ; Streptococcus mutans/*drug effects/physiology ; Surface Properties ; Tooth Demineralization/*drug therapy/prevention & control ; }, abstract = {OBJECTIVE: This study investigated the anti-demineralizing and antibacterial effects of a propolis ethanolic extract (EEP) against Streptococcus mutans dental biofilm.

DESIGN: Blocks of sound bovine enamel (n=24) were fixed on polystyrene plates. S. mutans inoculum (ATCC 25175) and culture media were added (48 h-37 °C) to form biofilm. Blocks with biofilm received daily treatment (30 μL/1 min), for 5 days, as following: G1 (EEP 33.3%); G2 (chlorhexidine digluconate 0.12%); G3 (ethanol 80%); and G4 (Milli-Q water). G5 and G6 were blocks without biofilm that received only EEP and Milli-Q water, respectively. Final surface hardness was evaluated and the percentage of hardness loss (%HL) was calculated. The EEP extract pH and total solids were determined. S. mutans count was expressed by log10 scale of Colony-Forming Units (CFU/mL). One way ANOVA was used to compare results which differed at a 95% significance level.

RESULTS: G2 presented the lowest average %HL value (68.44% ± 12.98) (p=0.010), while G4 presented the highest (90.49% ± 5.38%HL) (p=0.007). G1 showed %HL (84.41% ± 2.77) similar to G3 (87.80% ± 6.89) (p=0.477). Groups G5 and G6 presented %HL=16.11% ± 7.92 and 20.55% ± 10.65; respectively (p=0.952). G1 and G4 differed as regards to S. mutans count: 7.26 ± 0.08 and 8.29 ± 0.17 CFU/mL, respectively (p=0.001). The lowest bacterial count was observed in chlorhexidine group (G2=6.79 ± 0.10 CFU/mL) (p=0.043). There was no difference between S. mutans count of G3 and G4 (p=0.435). The EEP showed pH 4.8 and total soluble solids content=25.9 Brix.

CONCLUSION: The EEP seems to be a potent antibacterial substance against S. mutans dental biofilm, but presented no inhibitory action on the de-remineralization of caries process.}, } @article {pmid26870681, year = {2016}, author = {Dwivedi, D and Singh, V}, title = {Effects of the natural compounds embelin and piperine on the biofilm-producing property of Streptococcus mutans.}, journal = {Journal of traditional and complementary medicine}, volume = {6}, number = {1}, pages = {57-61}, pmid = {26870681}, issn = {2225-4110}, abstract = {We aimed to evaluate the effects of the natural compounds embelin and piperine on the biofilm-formation property of Streptococcus mutans. A total of 30 clinical isolates were identified as S. mutans and screened for biofilm formation using the microtiter plate method. The strongest biofilm producer (SM03) was used for identifying both minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC). We subsequently used this concentration against each of the strong biofilm producer isolates at A 492 < 0.5 optical density (OD). Of the 30 isolates screened for biofilm formation, 18 isolates showed strong biofilm formation, 09 isolates showed moderate formation, and 03 isolates showed poor/nonbiofilm formation. The MIC of embelin for the strongest biofilm producer (SM03) was 0.55 ± 0.02, whereas that of piperine was 0.33 ± 0.02. The MBIC of embelin was 0.0620 ± 0.03, whereas that of piperine was 0.0407 ± 0.03, which was lower than that of embelin. At OD492 < 0.5, the MBIC of both compounds significantly inhibited biofilm formation of all the 18 strong biofilm-forming isolates. The results of this study demonstrate a significant antibiofilm effect of the natural compounds embelin and piperine, which can contribute towards the development of a database for novel drug candidates for treating oral infections caused by S. mutans.}, } @article {pmid26868903, year = {2016}, author = {Bumroongthai, K and Chetanachan, P and Niyomtham, W and Yurayart, C and Prapasarakul, N}, title = {Biofilm production and antifungal susceptibility of co-cultured Malassezia pachydermatis and Candida parapsilosis isolated from canine seborrheic dermatitis.}, journal = {Medical mycology}, volume = {54}, number = {5}, pages = {544-549}, doi = {10.1093/mmy/myw002}, pmid = {26868903}, issn = {1460-2709}, mesh = {Animals ; Antifungal Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Candida/*drug effects/isolation & purification/physiology ; Dermatitis, Seborrheic/microbiology/*veterinary ; Dog Diseases/*microbiology ; Dogs ; Itraconazole/pharmacology ; Ketoconazole/pharmacology ; Malassezia/*drug effects/isolation & purification/physiology ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; }, abstract = {The yeasts Malassezia (M.) pachydermatis and Candida (C.) parapsilosis are often co-isolated in case of canine seborrhea dermatitis (SD) and also are emerging as opportunistic pathogens of immunocompromised human beings. Increased information about how their relationship results in biofilm production and an antifungal response would be useful to inform treatment and control. This study was designed to investigate biofilm production derived from co-culture of M. pachydermatis and C. parapsilosis from dog skin and to determine their in vitro antifungal susceptibility. We demonstrated that regardless of yeast strain or origin all single and dual cultures produced biofilms within 24 hours, and the greatest amount was present after 72 hours. Biofilm production from mixed cultures was greater than for single strains (P < .05). All sessile forms of the single and dual cultures were resistant to the tested antifungals itraconazole and ketoconazole, whereas planktonic forms were susceptible. The study suggests that dual cultures produce stronger biofilms that are likely to enhance persistence in skin lesions in dogs and result in greater resistance to antifungal treatment.}, } @article {pmid26868151, year = {2016}, author = {Hultberg, M and Olsson, LE and Birgersson, G and Gustafsson, S and Sievertsson, B}, title = {Microalgal growth in municipal wastewater treated in an anaerobic moving bed biofilm reactor.}, journal = {Bioresource technology}, volume = {207}, number = {}, pages = {19-23}, doi = {10.1016/j.biortech.2016.02.001}, pmid = {26868151}, issn = {1873-2976}, mesh = {Biodegradation, Environmental ; *Biofilms ; Biomass ; Bioreactors/*microbiology ; *Cities ; Esters/analysis ; Lipids ; Microalgae/*growth & development ; Nitrogen/isolation & purification ; Phosphorus/isolation & purification ; Wastewater/*microbiology ; Water Purification/*methods ; }, abstract = {Nutrient removal from the effluent of an anaerobic moving bed biofilm reactor (AnMBBR) treated with microalgae was evaluated. Algal treatment was highly efficient in removal of nutrients and discharge limits were met after 3days. Extending the cultivation time from 3 to 5days resulted in a large increase in biomass, from 233.3±49.3 to 530.0±72.1mgL(-1), despite nutrients in the water being exhausted after 3days (ammonium 0.04mgL(-1), orthophosphate <0.05mgL(-1)). Biomass productivity, lipid content and quality did not differ in microalgal biomass produced in wastewater sampled before the AnMBBR. The longer cultivation time resulted in a slight increase in total lipid concentration and a significant decrease in linolenic acid concentration in all treatments. Differences were observed in chemical oxygen demand, which decreased after algal treatment in wastewater sampled before the AnMBBR whereas it increased after algal treatment in the effluent from the AnMBBR.}, } @article {pmid26864892, year = {2016}, author = {Bennett, RR and Lee, CK and De Anda, J and Nealson, KH and Yildiz, FH and O'Toole, GA and Wong, GC and Golestanian, R}, title = {Species-dependent hydrodynamics of flagellum-tethered bacteria in early biofilm development.}, journal = {Journal of the Royal Society, Interface}, volume = {13}, number = {115}, pages = {20150966}, pmid = {26864892}, issn = {1742-5662}, support = {R01 AI102584/AI/NIAID NIH HHS/United States ; R37 AI083256/AI/NIAID NIH HHS/United States ; AI102584/AI/NIAID NIH HHS/United States ; R01 2 R37 AI83256-06/AI/NIAID NIH HHS/United States ; }, mesh = {Bacterial Adhesion/physiology ; Biofilms/*growth & development ; Flagella/*physiology ; Hydrodynamics ; Pseudomonas aeruginosa/*physiology ; Shewanella/*physiology ; Species Specificity ; Vibrio cholerae/*physiology ; }, abstract = {Monotrichous bacteria on surfaces exhibit complex spinning movements. Such spinning motility is often a part of the surface detachment launch sequence of these cells. To understand the impact of spinning motility on bacterial surface interactions, we develop a hydrodynamic model of a surface-bound bacterium, which reproduces behaviours that we observe in Pseudomonas aeruginosa, Shewanella oneidensis and Vibrio cholerae, and provides a detailed dictionary for connecting observed spinning behaviour to bacteria-surface interactions. Our findings indicate that the fraction of the flagellar filament adhered to the surface, the rotation torque of this appendage, the flexibility of the flagellar hook and the shape of the bacterial cell dictate the likelihood that a microbe will detach and the optimum orientation that it should have during detachment. These findings are important for understanding species-specific reversible attachment, the key transition event between the planktonic and biofilm lifestyle for motile, rod-shaped organisms.}, } @article {pmid26863404, year = {2016}, author = {Liu, Z and Ma, S and Duan, S and Xuliang, D and Sun, Y and Zhang, X and Xu, X and Guan, B and Wang, C and Hu, M and Qi, X and Zhang, X and Gao, P}, title = {Modification of Titanium Substrates with Chimeric Peptides Comprising Antimicrobial and Titanium-Binding Motifs Connected by Linkers To Inhibit Biofilm Formation.}, journal = {ACS applied materials & interfaces}, volume = {8}, number = {8}, pages = {5124-5136}, doi = {10.1021/acsami.5b11949}, pmid = {26863404}, issn = {1944-8252}, mesh = {Anti-Infective Agents/chemistry/therapeutic use ; Bacterial Adhesion/drug effects ; Biofilms/drug effects ; Coated Materials, Biocompatible/chemistry/*therapeutic use ; Dental Implants/adverse effects/*microbiology ; Humans ; Microscopy, Atomic Force ; Peptides/*chemistry/therapeutic use ; Quartz Crystal Microbalance Techniques ; Streptococcus gordonii/drug effects ; Surface Properties ; Titanium/*chemistry/therapeutic use ; }, abstract = {Bacterial adhesion and biofilm formation are the primary causes of implant-associated infection, which is difficult to eliminate and may induce failure in dental implants. Chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit biofilm formation on titanium surfaces. In this study, chimeric peptides were designed by connecting an antimicrobial motif (JH8194: KRLFRRWQWRMKKY) with a binding motif (minTBP-1: RKLPDA) directly or via flexible/rigid linkers to modify Ti surfaces. We evaluated the binding behavior of peptides using quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques and investigated the effect of the modification of titanium surfaces with these peptides on the bioactivity of Streptococcus gordonii (S. gordonii) and Streptococcus sanguis (S. sanguis). Compared with the flexible linker (GGGGS), the rigid linker (PAPAP) significantly increased the adsorption of the chimeric peptide on titanium surfaces (p < 0.05). Concentration-dependent adsorption is consistent with a single Langmuir model, whereas time-dependent adsorption is in line with a two-domain Langmuir model. Additionally, the chimeric peptide with the rigid linker exhibited more effective antimicrobial ability than the peptide with the flexible linker. This finding was ascribed to the ability of the rigid linker to separate functional domains and reduce their interference to the maximum extent. Consequently, the performance of chimeric peptides with specific titanium-binding motifs and antimicrobial motifs against bacteria can be optimized by the proper selection of linkers. This rational design of chimeric peptides provides a promising alternative to inhibit the formation of biofilms on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.}, } @article {pmid26862516, year = {2016}, author = {Garvey, M and Coughlan, G and Murphy, N and Rowan, N}, title = {The pulsed light inactivation of veterinary relevant microbial biofilms and the use of a RTPCR assay to detect parasite species within biofilm structures.}, journal = {Open veterinary journal}, volume = {6}, number = {1}, pages = {15-22}, pmid = {26862516}, issn = {2226-4485}, abstract = {The presence of pathogenic organisms namely parasite species and bacteria in biofilms in veterinary settings, is a public health concern in relation to human and animal exposure. Veterinary clinics represent a significant risk factor for the transfer of pathogens from housed animals to humans, especially in cases of wound infection and the shedding of faecal matter. This study aims to provide a means of detecting veterinary relevant parasite species in bacterial biofilms, and to provide a means of disinfecting these biofilms. A real time PCR assay was utilized to detect parasite DNA in Bacillus cereus biofilms on stainless steel and PVC surfaces. Results show that both Cryptosporidium and Giardia attach to biofilms in large numbers (100-1000 oo/cysts) in as little as 72 hours. Pulsed light successfully inactivated all test species (Listeria, Salmonella, Bacillus, Escherichia) in planktonic and biofilm form with an increase in inactivation for every increase in UV dose.}, } @article {pmid26862039, year = {2016}, author = {William da Fonseca Batistão, D and Amaral de Campos, P and Caroline Camilo, N and Royer, S and Fuga Araújo, B and Spirandelli Carvalho Naves, K and Martins, M and Olívia Pereira, M and Henriques, M and Pinto Gontijo-Filho, P and Botelho, C and Oliveira, R and Marques Ribas, R}, title = {Biofilm formation of Brazilian meticillin-resistant Staphylococcus aureus strains: prevalence of biofilm determinants and clonal profiles.}, journal = {Journal of medical microbiology}, volume = {65}, number = {4}, pages = {286-297}, doi = {10.1099/jmm.0.000228}, pmid = {26862039}, issn = {1473-5644}, abstract = {Biofilms plays an important role in medical-device-related infections. This study aimed to determine the factors that influence adherence and biofilm production, as well as the relationship between strong biofilm production and genetic determinants in clinical isolates of meticillin-resistant Staphylococcus aureus (MRSA). Fifteen strains carrying different chromosomal cassettes recovered from hospitalized patients were selected; five SCCmecII, five SCCmecIII and five SCCmecIV. The SCCmec type, agr group and the presence of the virulence genes (bbp, clfA, icaA, icaD, fnbB, bap, sasC and IS256) were assessed by PCR. PFGE and multilocus sequence typing (MLST) techniques were also performed. The initial adhesion and biofilm formation were examined by quantitative assays. The surface tension and hydrophobicity of the strains were measured by the contact angle technique to evaluate the association between these parameters and adhesion ability. SCCmecIII and IV strains were less hydrophilic, with a high value for the electron acceptor parameter and higher adhesion in comparison with SCCmecII strains. Only SCCmecIII strains could be characterized as strong biofilm producers. The PFGE showed five major pulsotypes (A-E); however, biofilm production was related to the dissemination of one specific PFGE clone (C) belonging to MLST ST239 (Brazilian epidemic clonal complex). The genes agrI, fnbB and IS256 in SCCmecIII strains were considered as genetic determinants associated with strong biofilm-formation by an ica-independent biofilm pathway. This study contributes to the understanding of biofilm production as an aggravating factor potentially involved in the persistence and severity of infections caused by multidrug-resistant MRSA belonging to this genotype.}, } @article {pmid26861975, year = {2016}, author = {Silva, MP and dos Santos, TA and de Barros, PP and de Camargo Ribeiro, F and Junqueira, JC and Jorge, AO}, title = {Action of antimicrobial photodynamic therapy on heterotypic biofilm: Candida albicans and Bacillus atrophaeus.}, journal = {Lasers in medical science}, volume = {31}, number = {4}, pages = {605-610}, pmid = {26861975}, issn = {1435-604X}, mesh = {Anti-Bacterial Agents/pharmacology ; Antifungal Agents/pharmacology ; Bacillus/*drug effects/radiation effects ; Biofilms/*drug effects/radiation effects ; Candida albicans/*drug effects/physiology ; Lasers, Semiconductor ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Rose Bengal/pharmacology ; }, abstract = {The increase in survival and resistance of microorganisms organized in biofilms demonstrates the need for new studies to develop therapies able to break this barrier, such as photodynamic therapy, which is characterized as an alternative, effective, and non-invasive treatment. The objective was to evaluate in vitro the effect of antimicrobial photodynamic therapy on heterotypic biofilms of Candida albicans and Bacillus atrophaeus using rose bengal (12.5 μM) and light-emitting diode (LED) (532 nm and 16.2 J). We used standard strains of B. atrophaeus (ATCC 9372) and C. albicans (ATCC 18804). The biofilm was formed in the bottom of the plate for 48 h. For the photodynamic therapy (PDT) experimental groups, we added 100 μL of rose bengal with LED (P+L+), 100 μL of rose bengal without LED (P+L-), 100 μL of NaCl 0.9 % solution with LED (P-L+), and a control group without photosensitizer or LED (P-L-). The plates remained in agitation for 5 min (pre-irradiation) and were irradiated with LED for 3 min, and the biofilm was detached using an ultrasonic homogenizer for 30 s. Serial dilutions were plated in BHI agar and HiChrom agar and incubated at 37 °C/48 h. There was a reduction of 33.92 and 29.31 % of colony-forming units per milliliter (CFU/mL) for C. albicans and B. atrophaeus, respectively, from the control group to the group subjected to PDT. However, statistically significant differences were not observed among the P+L+, P+L-, P-L+, and P-L- groups. These results suggest that antimicrobial photodynamic therapy using rose bengal (12.5 μM) with a pre-irradiation period of 5 min and LED for 3 min was not enough to cause a significant reduction in the heterotypic biofilms of C. albicans and B. atrophaeus.}, } @article {pmid26861950, year = {2016}, author = {Sojka, M and Valachova, I and Bucekova, M and Majtan, J}, title = {Antibiofilm efficacy of honey and bee-derived defensin-1 on multispecies wound biofilm.}, journal = {Journal of medical microbiology}, volume = {65}, number = {4}, pages = {337-344}, doi = {10.1099/jmm.0.000227}, pmid = {26861950}, issn = {1473-5644}, abstract = {Many clinically relevant biofilms are polymicrobial. Examining the effect of antimicrobials in a multispecies biofilm consortium is of great clinical importance. The goal of this study was to investigate the effect of different honey types against bacterial wound pathogens grown in multispecies biofilm and to test the antibiofilm activity of honey defensin-1 (Def-1) in its recombinant form. A modified Lubbock chronic wound biofilm formed by four bacterial species (Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa and Enterococcus faecalis) was used for evaluation of honey and recombinant bee-derived Def-1 antibiofilm efficacy. Recombinant Def-1 was prepared by heterologous expression in Escherichia coli. We showed that different types of honey (manuka and honeydew) were able to significantly reduce the cell viability of wound pathogens (Staphylococcus aureus, Streptococcus agalactiae and Pseudomonas aeruginosa) in mature polymicrobial biofilm. None of the tested honeys showed the ability to eradicate Enterococcus faecalis in biofilm. In addition, recombinant Def-1 successfully reduced the viability of Staphylococcus aureus and Pseudomonas aeruginosa cells within established polymicrobial biofilm after 24 and 48 h of treatment. Interestingly, recombinant Def-1 did not affect the viability of Streptococcus agalactiae cells within the biofilm, whereas both natural honeys significantly reduced the viable bacteria. Although Enterococcus faecalis was highly resistant to Def-1, Def-1 significantly affected the biofilm formation of Enterococcus faecalis and Streptococcus agalactiae after 24 h of treatment, most likely by inhibiting its extracellular polymeric substances production. In conclusion, our study revealed that honey and Def-1 are effective against established multispecies biofilm; however, Enterococcus faecalis grown in multispecies biofilm was resistant to both antimicrobials.}, } @article {pmid26861151, year = {2016}, author = {Stoodley, P}, title = {CORR Insights(®): Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time.}, journal = {Clinical orthopaedics and related research}, volume = {474}, number = {7}, pages = {1665-1667}, pmid = {26861151}, issn = {1528-1132}, mesh = {Anti-Bacterial Agents/therapeutic use ; *Anti-Infective Agents ; *Biofilms ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; }, } @article {pmid26860452, year = {2016}, author = {Rahim, MI and Rohde, M and Rais, B and Seitz, JM and Mueller, PP}, title = {Susceptibility of metallic magnesium implants to bacterial biofilm infections.}, journal = {Journal of biomedical materials research. Part A}, volume = {104}, number = {6}, pages = {1489-1499}, doi = {10.1002/jbm.a.35680}, pmid = {26860452}, issn = {1552-4965}, mesh = {*Absorbable Implants ; Animals ; Bacterial Infections/*microbiology ; Biofilms/*drug effects ; Colony Count, Microbial ; Drug Resistance, Microbial/drug effects ; Female ; Magnesium/*pharmacology ; Mice, Inbred BALB C ; Prosthesis-Related Infections/*microbiology ; Pseudomonas aeruginosa/drug effects/growth & development ; Staphylococcus aureus/drug effects ; }, abstract = {Magnesium alloys have promising mechanical and biological properties as biodegradable medical implant materials for temporary applications during bone healing or as vascular stents. Whereas conventional implants are prone to colonization by treatment resistant microbial biofilms in which bacteria are embedded in a protective matrix, magnesium alloys have been reported to act antibacterial in vitro. To permit a basic assessment of antibacterial properties of implant materials in vivo an economic but robust animal model was established. Subcutaneous magnesium implants were inoculated with bacteria in a mouse model. Contrary to the expectations, bacterial activity was enhanced and prolonged in the presence of magnesium implants. Systemic antibiotic treatments were remarkably ineffective, which is a typical property of bacterial biofilms. Biofilm formation was further supported by electron microscopic analyses that revealed highly dense bacterial populations and evidence for the presence of extracellular matrix material. Bacterial agglomerates could be detected not only on the implant surface but also at a limited distance in the peri-implant tissue. Therefore, precautions may be necessary to minimize risks of metallic magnesium-containing implants in prospective clinical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1489-1499, 2016.}, } @article {pmid26858552, year = {2016}, author = {Murugan, K and Selvanayaki, K and Al-Sohaibani, S}, title = {Urinary catheter indwelling clinical pathogen biofilm formation, exopolysaccharide characterization and their growth influencing parameters.}, journal = {Saudi journal of biological sciences}, volume = {23}, number = {1}, pages = {150-159}, pmid = {26858552}, issn = {1319-562X}, abstract = {Self-reproducing microbial biofilm community mainly involved in the contamination of indwelling medical devices including catheters play a vital role in nosocomial infections. The catheter-associated urinary tract infection (CA-UTI) causative Staphylococcus aureus, Enterobacter faecalis, and Pseudomonas aeruginosa were selectively isolated, their phenotypic as well as genotypic biofilm formation, production and monomeric sugar composition of EPS as well as sugar, salt, pH and temperature influence on their in vitro biofilm formation were determined. From 50 culture positive urinary catheters S. aureus (24%), P. aeruginosa (18%), E. faecalis (14%) and others (44%) were isolated. The performed assays revealed their varying biofilm forming ability. The isolated S. aureus ica, E. faecalis esp, and P. aeruginosa cup A gene sequencing and phylogenetic analysis showed their close branching and genetic relationship. The analyzed sugar, salt, pH, and temperature showed that the degree of CA-UTI isolates biofilm formation is an environmentally sensitive process. EPS monosaccharide HPLC analysis showed the presence of neutral sugars (ng/μl) as follows: glucose (P. aeruginosa: 44.275; E. faecalis: 4.23), lactose (P. aeruginosa: 7.29), mannitol (P. aeruginosa: 2.53; S. aureus: 2.62; E. faecalis: 2.054) and maltose (E. faecalis: 7.0042) revealing species-specific presence and variation. This study may have potential clinical relevance for the easy diagnosis and management of CA-UTI.}, } @article {pmid26858204, year = {2016}, author = {Huerta, JM and Aguilar, I and López-Pliego, L and Fuentes-Ramírez, LE and Castañeda, M}, title = {The Role of the ncRNA RgsA in the Oxidative Stress Response and Biofilm Formation in Azotobacter vinelandii.}, journal = {Current microbiology}, volume = {72}, number = {6}, pages = {671-679}, pmid = {26858204}, issn = {1432-0991}, mesh = {Azotobacter vinelandii/genetics/*physiology ; Bacterial Proteins/genetics/metabolism ; Base Sequence ; *Biofilms ; Gene Expression Regulation, Bacterial ; Molecular Sequence Data ; *Oxidative Stress ; Promoter Regions, Genetic ; RNA, Bacterial/genetics/*metabolism ; RNA, Long Noncoding/genetics/*metabolism ; Sigma Factor/genetics/metabolism ; }, abstract = {Azotobacter vinelandii is a soil bacterium that forms desiccation-resistant cysts, and the exopolysaccharide alginate is essential for this process. A. vinelandii also produces alginate under vegetative growth conditions, and this production has biotechnological significance. Poly-β-hydroxybutyrate (PHB) is another polymer synthetized by A. vinelandii that is of biotechnological interest. The GacS/A two-component signal transduction system plays an important role in regulating alginate production, PHB synthesis, and encystment. GacS/A in turn controls other important regulators such as RpoS and the ncRNAs that belong to the Rsm family. In A. vinelandii, RpoS is necessary for resisting oxidative stress as a result of its control over the expression of the catalase Kat1. In this work, we characterized a new ncRNA in A. vinelandii that is homologous to the P16/RsgA reported in Pseudomonas. We found that the expression of rgsA is regulated by GacA and RpoS and that it was essential for oxidative stress resistance. However, the activity of the catalase Kat1 is unaffected in rgsA mutants. Unlike those reported in Pseudomonas, RgsA in A. vinelandii regulates biofilm formation but not polymer synthesis or the encystment process.}, } @article {pmid26857006, year = {2016}, author = {Barwal, A and Chaudhary, R}, title = {Application of response surface methodology to optimize the operational parameters for enhanced removal efficiency of organic matter and nitrogen: moving bed biofilm reactor.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {10}, pages = {9944-9955}, pmid = {26857006}, issn = {1614-7499}, mesh = {Analysis of Variance ; *Biofilms ; Biological Oxygen Demand Analysis ; *Bioreactors ; Nitrogen/analysis ; Wastewater/analysis ; Water Pollutants, Chemical/isolation & purification ; Water Purification/*instrumentation/methods ; }, abstract = {An attempt of response surface methodology (RSM) has been made for more effective utilization and optimization for considerable reduction of operational conditions such as reaction time, aeration time, energy consumption, etc. for municipal wastewater treatment process using moving bed biofilm reactor (MBBR). A mathematical-statistical model was developed for the second-order response surface through the fit of a polynomial function and a central composite design (CCD) in the form of a full factorial design. CCD was employed to assess the interactive effects of the three main independent operational parameters, including biocarrier filling rate (0-70 %), aeration rate (0.21-0.42 m(3) h(-1)), and reactor run time (1-15 days), on the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total Kjeldahl nitrogen (TKN). Analysis of variance expressed a high coefficient of determination (R (2) = 0.84-0.95), thereby indicating that the model is significant. Using a desirability function for the highest COD (93 %), BOD (96 %), and TKN (69 %) removal, the optimum carrier filling rate, aeration rate, and reactor run time were identified to be 40 %, 0.21 m(3) h(-1), and 7 days, respectively. It shows that RSM can be a suitable method to optimize the operational parameters of MBBR with enhanced removal efficiency and less power consumption.}, } @article {pmid26856845, year = {2016}, author = {Allan, RN and Morgan, S and Brito-Mutunayagam, S and Skipp, P and Feelisch, M and Hayes, SM and Hellier, W and Clarke, SC and Stoodley, P and Burgess, A and Ismail-Koch, H and Salib, RJ and Webb, JS and Faust, SN and Hall-Stoodley, L}, title = {Low Concentrations of Nitric Oxide Modulate Streptococcus pneumoniae Biofilm Metabolism and Antibiotic Tolerance.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {4}, pages = {2456-2466}, pmid = {26856845}, issn = {1098-6596}, support = {//Wellcome Trust/United Kingdom ; }, mesh = {Adenoids/drug effects/microbiology ; Amoxicillin-Potassium Clavulanate Combination/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects/growth & development ; Child ; Child, Preschool ; Drug Resistance, Bacterial/drug effects ; Drug Synergism ; Drug Therapy, Combination ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Hydrazines/chemistry/pharmacology ; Nitrates/chemistry/pharmacology ; Nitric Oxide/chemistry/*pharmacology ; Nitric Oxide Donors/chemistry/*pharmacology ; Nitroprusside/chemistry/pharmacology ; Otitis Media/drug therapy/microbiology/pathology ; Pneumococcal Infections/drug therapy/microbiology/pathology ; Protein Biosynthesis ; Sodium Nitrite/chemistry/pharmacology ; Streptococcus pneumoniae/*drug effects/genetics/growth & development ; Transcription, Genetic/drug effects ; }, abstract = {Streptococcus pneumoniaeis one of the key pathogens responsible for otitis media (OM), the most common infection in children and the largest cause of childhood antibiotic prescription. Novel therapeutic strategies that reduce the overall antibiotic consumption due to OM are required because, although widespread pneumococcal conjugate immunization has controlled invasive pneumococcal disease, overall OM incidence has not decreased. Biofilm formation represents an important phenotype contributing to the antibiotic tolerance and persistence ofS. pneumoniaein chronic or recurrent OM. We investigated the treatment of pneumococcal biofilms with nitric oxide (NO), an endogenous signaling molecule and therapeutic agent that has been demonstrated to trigger biofilm dispersal in other bacterial species. We hypothesized that addition of low concentrations of NO to pneumococcal biofilms would improve antibiotic efficacy and that higher concentrations exert direct antibacterial effects. Unlike in many other bacterial species, low concentrations of NO did not result inS. pneumoniaebiofilm dispersal. Instead, treatment of bothin vitrobiofilms andex vivoadenoid tissue samples (a reservoir forS. pneumoniaebiofilms) with low concentrations of NO enhanced pneumococcal killing when combined with amoxicillin-clavulanic acid, an antibiotic commonly used to treat chronic OM. Quantitative proteomic analysis using iTRAQ (isobaric tag for relative and absolute quantitation) identified 13 proteins that were differentially expressed following low-concentration NO treatment, 85% of which function in metabolism or translation. Treatment with low-concentration NO, therefore, appears to modulate pneumococcal metabolism and may represent a novel therapeutic approach to reduce antibiotic tolerance in pneumococcal biofilms.}, } @article {pmid26856342, year = {2016}, author = {Zarrilli, R}, title = {Acinetobacter baumannii virulence determinants involved in biofilm growth and adherence to host epithelial cells.}, journal = {Virulence}, volume = {7}, number = {4}, pages = {367-368}, pmid = {26856342}, issn = {2150-5608}, mesh = {Acinetobacter Infections ; *Acinetobacter baumannii ; Bacterial Adhesion ; *Biofilms ; Epithelial Cells ; Humans ; Virulence ; }, } @article {pmid26855788, year = {2015}, author = {Oppong, GO and Rapsinski, GJ and Tursi, SA and Biesecker, SG and Klein-Szanto, AJ and Goulian, M and McCauley, C and Healy, C and Wilson, RP and Tükel, C}, title = {Biofilm-associated bacterial amyloids dampen inflammation in the gut: oral treatment with curli fibres reduces the severity of hapten-induced colitis in mice.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15019-}, pmid = {26855788}, issn = {2055-5008}, support = {R01 GM080279/GM/NIGMS NIH HHS/United States ; R03 AI107434/AI/NIAID NIH HHS/United States ; R21 AI105370/AI/NIAID NIH HHS/United States ; }, abstract = {BACKGROUND/OBJECTIVES: A disruption of epithelial barrier function can lead to intestinal inflammation. Toll-like receptor (TLR) 2 activation by microbial products promotes intestinal epithelial integrity and overall gut health. Several bacterial species, including enteric bacteria, actively produce amyloid proteins as a part of their biofilms. Recognition of amyloid fibres found in enteric biofilms, termed curli, by the Toll-like receptor (TLR)2/1 complex reinforces barrier function. Here, we investigated the effect of purified curli fibres on inflammation in a mouse model of acute colitis.

METHODS: Bone marrow-derived macrophages as well as lamina propria cells were treated with curli fibres of both pathogenic Salmonella enterica serovar Typhimurium and commensal Escherichia coli Nissle 1917 biofilms. Mice were given 0.1 or 0.4 mg of purified curli orally 1 day post administration of 1% 2,4,6-trinitrobenzene sulphonic acid (TNBS) enema. Histopathological analysis was performed on distal colonic tissue taken 6 days post TNBS enema. RNA extracted from colonic tissue was subjected to RT-PCR.

RESULTS: Here we show that curli fibres of both pathogenic and commensal bacteria are recognised by TLR2 leading to the production of IL-10, immunomodulatory cytokine of intestinal homeostasis. Treatment of mice with a single dose of curli heightens transcript levels of Il10 in the colon and ameliorates the disease pathology in TNBS-induced colitis. Curli treatment is comparable to the treatment with anti-tumour necrosis factor alpha (anti-TNFα) antibodies, a treatment known to reduce the severity of acute colitis in humans and mice.

CONCLUSION: These results suggest that the bacterial amyloids had a role in helping to maintain immune homeostasis in the intestinal mucosa via the TLR2/IL-10 axis. Furthermore, bacterial amyloids may be a potential candidate therapeutic to treat intestinal inflammatory disorders owing to their remarkable immunomodulatory activity.}, } @article {pmid26855739, year = {2015}, author = {Emami, S and Nikokar, I and Ghasemi, Y and Ebrahimpour, M and Sedigh Ebrahim-Saraie, H and Araghian, A and Faezi, S and Farahbakhsh, M and Rajabi, A}, title = {Antibiotic Resistance Pattern and Distribution of pslA Gene Among Biofilm Producing Pseudomonas aeruginosa Isolated From Waste Water of a Burn Center.}, journal = {Jundishapur journal of microbiology}, volume = {8}, number = {11}, pages = {e23669}, pmid = {26855739}, issn = {2008-3645}, abstract = {BACKGROUND: Pseudomonas aeruginosa is considered as a major cause of hospital-acquired infections due to its high antibacterial resistance. Biofilm formation is a well-known pathogenic mechanism in P. aeruginosa infections, since sessile bacteria are protected in an extracellular matrix of exopolysaccharide. The expression of polysaccharide synthesis locus (pslA gene) can be important for biofilm formation by P. aeruginosa.

OBJECTIVES: The purpose of this research was to evaluate the antibiotic resistance pattern and distribution of the pslA gene among biofilm-producing P. aeruginosa isolates obtained from waste water of Burn Centre in Guilan, Iran.

MATERIALS AND METHODS: Fifty isolates of P. aeruginosa were obtained from waste water of a burn center. The P. aeruginosa isolates were identified using standard bacteriological procedures. Drug susceptibility test was performed by disk diffusion method for all the isolates against nine antimicrobial agents. Biofilm formation was measured by microtiter plate assay. Polymerase chain reaction (PCR) was used to identify the presence of the pslA gene among the isolates.

RESULTS: Biofilm formation was observed in 70% of the P. aeruginosa isolates. The potential formation of biofilm was significantly associated with resistance to gentamicin, imipenem, tobramycin and piperacillin. In addition, the pslA gene only existed in biofilm-producing isolates with a frequency of 42.9% (n = 15).

CONCLUSIONS: The findings of the present study well demonstrated that the P. aeruginosa biofilm-producing isolates were more resistant to the tested antibiotics. Furthermore, because of wide distribution, it seems that the pslA gene is associated with biofilm formation.}, } @article {pmid26854744, year = {2016}, author = {Álvarez-Fraga, L and Pérez, A and Rumbo-Feal, S and Merino, M and Vallejo, JA and Ohneck, EJ and Edelmann, RE and Beceiro, A and Vázquez-Ucha, JC and Valle, J and Actis, LA and Bou, G and Poza, M}, title = {Analysis of the role of the LH92_11085 gene of a biofilm hyper-producing Acinetobacter baumannii strain on biofilm formation and attachment to eukaryotic cells.}, journal = {Virulence}, volume = {7}, number = {4}, pages = {443-455}, pmid = {26854744}, issn = {2150-5608}, mesh = {A549 Cells ; Acinetobacter baumannii/*genetics/pathogenicity/*physiology/ultrastructure ; Alveolar Epithelial Cells/microbiology ; *Bacterial Adhesion ; Bacterial Proteins/*genetics/isolation & purification/metabolism ; Biofilms/*growth & development ; Fimbriae, Bacterial/genetics ; Genes, Bacterial ; Humans ; Microscopy, Electron, Scanning ; Virulence/genetics ; }, abstract = {Acinetobacter baumannii is a nosocomial pathogen that has a considerable ability to survive in the hospital environment partly due to its capacity to form biofilms. The first step in the process of establishing an infection is adherence of the bacteria to target cells. Chaperone-usher pili assembly systems are involved in pilus biogenesis pathways that play an important role in adhesion to host cells and tissues as well as medically relevant surfaces. After screening a collection of strains, a biofilm hyper-producing A. baumannii strain (MAR002) was selected to describe potential targets involved in pathogenicity. MAR002 showed a remarkable ability to form biofilm and attach to A549 human alveolar epithelial cells. Analysis of MAR002 using transmission electron microscopy (TEM) showed a significant presence of pili on the bacterial surface. Putative protein-coding genes involved in pili formation were identified based on the newly sequenced genome of MAR002 strain (JRHB01000001/2 or NZ_JRHB01000001/2). As assessed by qRT-PCR, the gene LH92_11085, belonging to the operon LH92_11070-11085, is overexpressed (ca. 25-fold more) in biofilm-associated cells compared to exponential planktonic cells. In the present work we investigate the role of this gene on the MAR002 biofilm phenotype. Scanning electron microscopy (SEM) and biofilm assays showed that inactivation of LH92_11085 gene significantly reduced bacterial attachment to A549 cells and biofilm formation on plastic, respectively. TEM analysis of the LH92_11085 mutant showed the absence of long pili formations normally present in the wild-type. These observations indicate the potential role this LH92_11085 gene could play in the pathobiology of A baumannii.}, } @article {pmid26854605, year = {2016}, author = {Yu, C and Li, X and Zhang, N and Wen, D and Liu, C and Li, Q}, title = {Inhibition of biofilm formation by D-tyrosine: Effect of bacterial type and D-tyrosine concentration.}, journal = {Water research}, volume = {92}, number = {}, pages = {173-179}, doi = {10.1016/j.watres.2016.01.037}, pmid = {26854605}, issn = {1879-2448}, mesh = {Bacillus subtilis/drug effects/growth & development/*physiology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/analysis ; Biofilms/*drug effects/growth & development ; Biomass ; Imaging, Three-Dimensional ; Polysaccharides, Bacterial/analysis ; Pseudomonas aeruginosa/drug effects/growth & development/*physiology ; Tyrosine/*pharmacology ; }, abstract = {D-Tyrosine inhibits formation and triggers disassembly of bacterial biofilm and has been proposed for biofouling control applications. This study probes the impact of D-tyrosine in different biofilm formation stages in both G+ and G- bacteria, and reveals a non-monotonic correlation between D-tyrosine concentration and biofilm inhibition effect. In the attachment stage, cell adhesion was studied in a flow chamber, where D-tyrosine caused significant reduction in cell attachment. Biofilms formed by Pseudomonas aeruginosa and Bacillus subtilis were characterized by confocal laser scanning microscopy as well as quantitative analysis of cellular biomass and extracellular polymeric substances. D-Tyrosine exhibited strong inhibitive effects on both biofilms with an effective concentration as low as 5 nM; the biofilms responded to D-tyrosine concentration change in a non-monotonic, bi-modal pattern. In addition, D-tyrosine showed notable and different impact on EPS production by G+ and G- bacteria. Extracellular protein was decreased in P. aeruginosa biofilms, but increased in those of B. subtilis. Exopolysaccharides production by P. aeruginosa was increased at low concentrations and reduced at high concentrations while no impact was found in B. subtilis. These results suggest that distinct mechanisms are at play at different D-tyrosine concentrations and they may be species specific. Dosage of D-tyrosine must be carefully controlled for biofouling control applications.}, } @article {pmid26854088, year = {2016}, author = {Zheng, D and Gao, M and Wang, Z and She, Z and Jin, C and Chang, Q}, title = {Performance comparison of biofilm and suspended sludge from a sequencing batch biofilm reactor treating mariculture wastewater under oxytetracycline stress.}, journal = {Environmental technology}, volume = {37}, number = {18}, pages = {2391-2404}, doi = {10.1080/09593330.2016.1150353}, pmid = {26854088}, issn = {1479-487X}, mesh = {Biofilms/*drug effects ; Bioreactors/*microbiology ; Oxytetracycline/*toxicity ; Sewage/*chemistry ; Wastewater/*chemistry ; Water Purification ; }, abstract = {The performance, extracellular polymeric substances (EPS) and microbial community of a sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater under oxytetracycline stress. The chemical oxygen demand and [Formula: see text]-N removal efficiencies of the SBBR decreased with the increase of oxytetracycline concentration, and no obvious [Formula: see text]-N and [Formula: see text]-N accumulation in the effluent appeared at less than 10 mg L(-1) oxytetracycline. The specific oxygen utilization rate of the suspended sludge was more than that of the biofilm at different oxytetracycline concentrations. The specific ammonium oxidation rate (SAOR) of the biofilm was more easily affected by oxytetracycline than that of the suspended sludge, whereas the effect of oxytetracycline on the specific nitrite oxidation rate (SNOR) of the biofilm was less than that of the suspended sludge. The specific nitrate reduction rate of both the biofilm and suspended sludge was higher than the sum of the SAOR and SNOR at different oxytetracycline concentrations. The protein and polysaccharide contents in the EPS of the biofilm and suspended sludge increased with the increase of oxytetracycline concentration. The appearance of oxytetracycline in the influent could affect the chemical composition of the loosely bound EPS and tightly bound EPS. The amino, carboxyl and hydroxyl groups might be involved with interaction between EPS and oxytetracycline. The denaturing gradient gel electrophoresis profiles indicated that the variation of oxytetracycline concentration in the influent could affect the microbial communities of both the biofilm and suspended sludge.}, } @article {pmid26853754, year = {2016}, author = {Fazly Bazzaz, BS and Khameneh, B and Zarei, H and Golmohammadzadeh, S}, title = {Antibacterial efficacy of rifampin loaded solid lipid nanoparticles against Staphylococcus epidermidis biofilm.}, journal = {Microbial pathogenesis}, volume = {93}, number = {}, pages = {137-144}, doi = {10.1016/j.micpath.2015.11.031}, pmid = {26853754}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/*chemistry/*pharmacology ; Biofilms/*drug effects ; Drug Carriers/chemistry ; Drug Compounding/*methods ; Humans ; Lipids/chemistry ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Particle Size ; Rifampin/*chemistry/*pharmacology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*drug effects/physiology ; }, abstract = {OBJECTIVE: The aim of the present study was to assess the in vitro anti-biofilm activities of solid lipid nanoparticles (SLN) loaded with rifampin against biofilm-producing Staphylococcus epidermidis.

METHODS: SLN were prepared and characterized for size, zeta potentials and encapsulation efficacy. The morphological and thermal properties of formulation were evaluated by TEM imagining and DSC analysis. The anti-biofilm activity of different formulations was assessed at different incubation times and concentrations by crystal violet (CV) and viable biofilm count methods.

RESULTS: The zeta potentials, particle sizes and encapsulation efficiencies of final formulations were 17 ± 0.7 mV, 101 ± 4.7 nm and approximately 70%; respectively. Rifampin-SLN was able to reduce the biomass of biofilm at time- and concentration-dependent manner. According to biofilm count results, the Rifampin-SLN was more effective for removal of the bacteria with respect to free rifampin.

CONCLUSION: The results of this study highlight the advantages and efficiency of Rifampin-SLN in biofilm eradication.}, } @article {pmid26853691, year = {2016}, author = {Petruzzi, B and Inzana, TJ}, title = {Exopolysaccharide Production and Biofilm Formation by Histophilus somni.}, journal = {Current topics in microbiology and immunology}, volume = {396}, number = {}, pages = {149-160}, doi = {10.1007/82_2015_5013}, pmid = {26853691}, issn = {0070-217X}, mesh = {Animals ; *Biofilms ; Cattle ; Pasteurellaceae/*physiology ; Polysaccharides, Bacterial/*biosynthesis ; }, abstract = {The biofilm matrix of Histophilus somni is a complex architecture that differs substantially in structure between a pathogenic and commensal isolate examined. Overall, most pathogenic isolates produce more biofilm than commensal isolates. A major component of the biofilm is exopolysaccharide (EPS), which is also produced in greater quantity in the pathogenic isolate than in the commensal isolate studied. The EPS is composed of a D-mannan polymer, with occasional galactose residues present on side chains, similar in composition to that of yeast mannan. When grown in the presence of sialic acid, the biofilm EPS becomes sialylated and the amino sugars N-acetylglucosamine and N-acetylgalactosamine can be detected. In vitro biofilm formation follows a typical 4-stage growth curve, characterized by attachment, growth, maturation, and detachment. Following experimental challenge, formation of an H. somni biofilm has been demonstrated in cardiopulmonary tissue, often with Pasteurella multocida cohabitating the biofilm. A recently developed diagnostic test can detect antibodies to the EPS only in animals with systemic disease due to H. somni and is therefore capable of distinguishing between healthy animals colonized with H. somni and animals with systemic disease.}, } @article {pmid26851196, year = {2016}, author = {Greene, C and Vadlamudi, G and Newton, D and Foxman, B and Xi, C}, title = {The influence of biofilm formation and multidrug resistance on environmental survival of clinical and environmental isolates of Acinetobacter baumannii.}, journal = {American journal of infection control}, volume = {44}, number = {5}, pages = {e65-71}, pmid = {26851196}, issn = {1527-3296}, support = {R01 GM098350/GM/NIGMS NIH HHS/United States ; T32 AI049816/AI/NIAID NIH HHS/United States ; }, mesh = {Acinetobacter Infections/*microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification/*physiology ; Adult ; Bacteriological Techniques ; Biofilms/drug effects/*growth & development ; *Drug Resistance, Multiple, Bacterial ; *Environmental Microbiology ; Female ; Genotyping Techniques ; Humans ; Male ; *Microbial Viability ; Middle Aged ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; }, abstract = {BACKGROUND: Acinetobacter baumannii is a gram-negative, opportunistic pathogen. Its ability to form biofilm and increasing resistance to antibiotic agents present challenges for infection control. A better understanding of the influence of biofilm formation and antibiotic resistance on environmental persistence of A baumannii in hospital settings is needed for more effective infection control.

METHODS: A baumannii strains isolated from patients and the hospital environment were identified via Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) mass spectrometry (Bruker Daltonics, Bellerica, MA), repetitive extragenic palindromic polymerase chain reaction genotyped, and antibiotic resistance was determined using Vitek 2 (bioMérieux, Inc, Durham NC). Biofilm mass was quantified via microtiter plate method and desiccation tolerance determined up to 56 days.

RESULTS: High biofilm forming, clinical, multidrug-resistant- (MDR) positive strains were 50% less likely to die of desiccation than low biofilm, non-MDR strains. In contrast, environmental, MDR-positive, low biofilm forming strains had a 2.7 times increase in risk of cell death due to desiccation compared with their MDR-negative counterparts. MDR-negative, high biofilm forming environmental strains had a 60% decrease in risk compared with their low biofilm forming counterparts.

CONCLUSION: The MDR-positive phenotype was deleterious for environmental strains and the high biofilm phenotype was critical for survival. This study provides evidence of the trade-off between antibiotic resistance and desiccation tolerance, driven by condition-dependent adaptation, and establishes rationale for research into the genetic basis of the variation in fitness cost between clinical and environmental isolates.}, } @article {pmid26850925, year = {2016}, author = {Bao, H and Zheng, Z and Yang, B and Liu, D and Li, F and Zhang, X and Li, Z and Lei, L}, title = {In situ monitoring of Shewanella oneidensis MR-1 biofilm growth on gold electrodes by using a Pt microelectrode.}, journal = {Bioelectrochemistry (Amsterdam, Netherlands)}, volume = {109}, number = {}, pages = {95-100}, doi = {10.1016/j.bioelechem.2016.01.008}, pmid = {26850925}, issn = {1878-562X}, mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth & development ; Electrochemical Techniques/instrumentation ; Equipment Design ; Gold/chemistry ; Microelectrodes ; Platinum/chemistry ; Shewanella/*physiology ; }, abstract = {Much attention has been focused on electrochemically active bacteria (EAB) in the application of bioelectrochemical systems (BESs). Studying the EAB biofilm growth mechanism as well as electron transfer mechanism provides a route to upgrade BES performance. But an effective bacterial growth monitoring method on the biofilm scale is still absent in this field. In this work, electrode-attached bacterial biofilms formed by Shewanella oneidensis MR-1 were dynamically monitored through a microelectrode method. For S. oneidensis MR-1, a respiratory electron transport chain is associated with the secretion of riboflavin, severing as the cofactor to the outer membrane c-type cytochromes. The biofilm growth was monitored through adopting riboflavin as an electrochemical probe during the approach of the microelectrode to the biofilm external surface. This method allows in vivo and in situ biofilm monitoring at different growth stages without destructive manipulation. Furthermore, the biofilm growth monitoring results have been proved to be relatively accurate through observation under confocal laser scanning microscopy. We further applied this method to investigate the effects of four environmental factors (the concentrations of dissolved oxygen, sodium lactate, riboflavin as well as the electrode potential) on S. oneidensis MR-1 biofilm development.}, } @article {pmid26850299, year = {2016}, author = {Folwell, BD and McGenity, TJ and Whitby, C}, title = {Biofilm and Planktonic Bacterial and Fungal Communities Transforming High-Molecular-Weight Polycyclic Aromatic Hydrocarbons.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {8}, pages = {2288-2299}, pmid = {26850299}, issn = {1098-5336}, mesh = {Bacteria/*metabolism ; *Biota ; Biotransformation ; Fungi/*metabolism ; Polycyclic Aromatic Hydrocarbons/*metabolism ; Water Pollutants/*metabolism ; }, abstract = {High-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[a]pyrene (44% ± 13.6%) and benzo[b]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs were Pseudomonas, Bacillus, and Microbacterium species. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation.}, } @article {pmid26847412, year = {2016}, author = {Soumya, KR and Mathew, S and Sugathan, S and Mathew, J and Radhakrishnan, EK}, title = {Studies on prevalence of biofilm associated genes and primary observation on sasX gene in clinical isolates of coagulase negative staphylococci (CoNS).}, journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica}, volume = {124}, number = {4}, pages = {319-326}, doi = {10.1111/apm.12510}, pmid = {26847412}, issn = {1600-0463}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism ; Bacterial Typing Techniques ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections/drug therapy/microbiology/pathology ; Coagulase/deficiency/genetics ; Doxycycline/pharmacology ; Drug Resistance, Multiple, Bacterial/genetics ; Gene Expression ; *Genes, Bacterial ; Genotype ; Humans ; Microbial Sensitivity Tests ; Prospective Studies ; Skin/microbiology ; Staphylococcal Infections/drug therapy/microbiology/pathology ; Staphylococcus aureus/drug effects/*genetics/isolation & purification/pathogenicity ; Staphylococcus haemolyticus/drug effects/*genetics/isolation & purification/pathogenicity ; }, abstract = {Coagulase negative staphylococci (CoNS) are nosocomial pathogens that cause indwelling medical device associated infections due to its biofilm forming potential and multiple antibiotic resistance. The current study focused on species identification, antibiotic resistance profile and molecular basis of biofilm formation and attachment of CoNS isolated from clinical samples. Along with this, molecular screening for mecA and newly identified surface colonization protein encoded by sasX gene was also conducted. S. epidermidis (n = 19, 47%) was identified as the most prevalent CoNS species and very interestingly two biofilm forming, mecA positive S. epidermidis isolates were found to carry all the biofilm associated genes screened in this study, which indicates its potential to form the strong biofilm. Another novel observation of the study is the detection of sasX gene in one biofilm positive S. epidermidis isolate. The study also identified one doxycycline resistant mecA positive, multidrug resistant S. haemolyticus isolate. In conclusion, the study signifies the existence of multiple biofilm related genes, multidrug resistance and the presence of sasX gene among clinical isolates of CoNS.}, } @article {pmid26847199, year = {2016}, author = {Parrilli, E and Ricciardelli, A and Casillo, A and Sannino, F and Papa, R and Tilotta, M and Artini, M and Selan, L and Corsaro, MM and Tutino, ML}, title = {Large-scale biofilm cultivation of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 for physiologic studies and drug discovery.}, journal = {Extremophiles : life under extreme conditions}, volume = {20}, number = {2}, pages = {227-234}, pmid = {26847199}, issn = {1433-4909}, mesh = {Anti-Bacterial Agents/*biosynthesis/pharmacology ; Biofilms/*drug effects ; Bioreactors ; Drug Discovery/instrumentation/*methods ; Fermentation ; Pseudoalteromonas/growth & development/*metabolism ; Staphylococcus epidermidis/drug effects/physiology ; }, abstract = {Microbial biofilms are mainly studied due to detrimental effects on human health but they are also well established in industrial biotechnology for the production of chemicals. Moreover, biofilm can be considered as a source of novel drugs since the conditions prevailing within biofilm can allow the production of specific metabolites. Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 when grown in biofilm condition produces an anti-biofilm molecule able to inhibit the biofilm of the opportunistic pathogen Staphylococcus epidermidis. In this paper we set up a P. haloplanktis TAC125 biofilm cultivation methodology in automatic bioreactor. The biofilm cultivation was designated to obtain two goals: (1) the scale up of cell-free supernatant production in an amount necessary for the anti-biofilm molecule/s purification; (2) the recovery of P. haloplanktis TAC125 cells grown in biofilm for physiological studies. We set up a fluidized-bed reactor fermentation in which floating polystyrene supports were homogeneously mixed, exposing an optimal air-liquid interface to let bacterium biofilm formation. The proposed methodology allowed a large-scale production of anti-biofilm molecule and paved the way to study differences between P. haloplanktis TAC125 cells grown in biofilm and in planktonic conditions. In particular, the modifications occurring in the lipopolysaccharide of cells grown in biofilm were investigated.}, } @article {pmid26847045, year = {2016}, author = {James, KM and MacDonald, KW and Chanyi, RM and Cadieux, PA and Burton, JP}, title = {Inhibition of Candida albicans biofilm formation and modulation of gene expression by probiotic cells and supernatant.}, journal = {Journal of medical microbiology}, volume = {65}, number = {4}, pages = {328-336}, doi = {10.1099/jmm.0.000226}, pmid = {26847045}, issn = {1473-5644}, mesh = {*Biofilms ; Candida albicans/*genetics/*physiology ; Epithelial Cells ; Fungal Proteins/*genetics ; *Gene Expression Regulation, Fungal ; Humans ; Hyphae/genetics/growth & development ; Lactobacillus helveticus ; Lactobacillus plantarum ; Probiotics/*pharmacology ; Real-Time Polymerase Chain Reaction ; Streptococcus salivarius ; Transcription Factors ; }, abstract = {Oral candidiasis is a disease caused by opportunistic species of Candida that normally reside on human mucosal surfaces. The transition of Candida from budding yeast to filamentous hyphae allows for covalent attachment to oral epithelial cells, followed by biofilm formation, invasion and tissue damage. In this study, combinations of Lactobacillus plantarum SD5870, Lactobacillus helveticus CBS N116411 and Streptococcus salivarius DSM 14685 were assessed for their ability to inhibit the formation of and disrupt Candida albicans biofilms. Co-incubation with probiotic supernatants under hyphae-inducing conditions reduced C. albicans biofilm formation by >75 % in all treatment groups. Likewise, combinations of live probiotics reduced biofilm formation of C. albicans by >67 %. When live probiotics or their supernatants were overlaid on preformed C. albicans biofilms, biofilm size was reduced by >63 and >65 % respectively. Quantitative real-time PCR results indicated that the combined supernatants of SD5870 and CBS N116411 significantly reduced the expression of several C. albicans genes involved in the yeast-hyphae transition: ALS3 (adhesin/invasin) by 70 % (P < 0.0001), EFG1 (hyphae-specific gene activator) by 47 % (P = 0.0061), SAP5 (secreted protease) by 49 % (P < 0.0001) and HWP1 (hyphal wall protein critical to biofilm formation) by >99 % (P < 0.0001). These findings suggest the combination of L. plantarum SD5870, L. helveticus CBS N116411 and S. salivarius DSM 14685 is effective at both preventing the formation of and removing preformed C. albicans biofilms. Our novel results point to the downregulation of several Candida genes critical to the yeast-hyphae transition, biofilm formation, tissue invasion and cellular damage.}, } @article {pmid26846970, year = {2016}, author = {Li, H and Zhou, E and Zhang, D and Xu, D and Xia, J and Yang, C and Feng, H and Jiang, Z and Li, X and Gu, T and Yang, K}, title = {Microbiologically Influenced Corrosion of 2707 Hyper-Duplex Stainless Steel by Marine Pseudomonas aeruginosa Biofilm.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {20190}, pmid = {26846970}, issn = {2045-2322}, mesh = {Biofilms/*growth & development ; Chromium/chemistry ; Corrosion ; Dielectric Spectroscopy ; Electrochemical Techniques ; Microscopy, Confocal ; Photoelectron Spectroscopy ; Pseudomonas aeruginosa/*physiology ; Stainless Steel/*chemistry ; Surface Properties ; }, abstract = {Microbiologically Influenced Corrosion (MIC) is a serious problem in many industries because it causes huge economic losses. Due to its excellent resistance to chemical corrosion, 2707 hyper duplex stainless steel (2707 HDSS) has been used in the marine environment. However, its resistance to MIC was not experimentally proven. In this study, the MIC behavior of 2707 HDSS caused by the marine aerobe Pseudomonas aeruginosa was investigated. Electrochemical analyses demonstrated a positive shift in the corrosion potential and an increase in the corrosion current density in the presence of the P. aeruginosa biofilm in the 2216E medium. X-ray photoelectron spectroscopy (XPS) analysis results showed a decrease in Cr content on the coupon surface beneath the biofilm. The pit imaging analysis showed that the P. aeruginosa biofilm caused a largest pit depth of 0.69 μm in 14 days of incubation. Although this was quite small, it indicated that 2707 HDSS was not completely immune to MIC by the P. aeruginosa biofilm.}, } @article {pmid26846651, year = {2016}, author = {de Campos, PA and Royer, S and Batistão, DW and Araújo, BF and Queiroz, LL and de Brito, CS and Gontijo-Filho, PP and Ribas, RM}, title = {Multidrug Resistance Related to Biofilm Formation in Acinetobacter baumannii and Klebsiella pneumoniae Clinical Strains from Different Pulsotypes.}, journal = {Current microbiology}, volume = {72}, number = {5}, pages = {617-627}, pmid = {26846651}, issn = {1432-0991}, mesh = {Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*drug effects/genetics/*isolation & purification/physiology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Brazil ; *Drug Resistance, Multiple, Bacterial ; Humans ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/*drug effects/genetics/isolation & purification/physiology ; }, abstract = {The emergence of Acinetobacter baumannii and Klebsiella pneumoniae strains in the hospital environment has been associated with the presence of multiple genetic elements, virulence factors and the ability to form biofilms. This study evaluated the biofilm formation ability of clinical and environmental A. baumannii and K. pneumoniae strains, isolated from various sources and presenting different molecular characteristics, resistance profiles and pulsed-field gel electrophoresis patterns. Fifty-three isolates were recovered from 2009 to 2014 in a Brazilian university hospital. Investigation of biofilm formation was performed for 10 strains of each species assessed by an initial adhesion assay, biofilm cell concentration and biofilm biomass, evaluated by quantitative assays in replicates, in three independent experiments. All strains of A. baumannii were able to attach to polystyrene plates, although two strains adhered to a lesser degree than the control. K. pneumoniae strains showed opposite behaviour, where only three strains adhered significantly when compared to the control. Quantitative evaluation revealed that in five A. baumannii and four K. pneumoniae isolates the biomass production could be characterised as moderate. None of the isolates were strong biofilm producers. Our results demonstrate: (1) biofilm formation is a heterogeneous property amongst A. baumannii and K. pneumoniae clinical strains and it was not associated with certain clonal types; (2) no relationship between multidrug resistance and biofilm production was observed; (3) more virulent K. pneumoniae strains tended to present higher production of biofilm.}, } @article {pmid26846404, year = {2016}, author = {Zegans, ME and DiGiandomenico, A and Ray, K and Naimie, A and Keller, AE and Stover, CK and Lalitha, P and Srinivasan, M and Acharya, NR and Lietman, TM}, title = {Association of Biofilm Formation, Psl Exopolysaccharide Expression, and Clinical Outcomes in Pseudomonas aeruginosa Keratitis: Analysis of Isolates in the Steroids for Corneal Ulcers Trial.}, journal = {JAMA ophthalmology}, volume = {134}, number = {4}, pages = {383-389}, doi = {10.1001/jamaophthalmol.2015.5956}, pmid = {26846404}, issn = {2168-6173}, support = {U10-EY015114-01/EY/NEI NIH HHS/United States ; }, mesh = {Adrenal Cortex Hormones/administration & dosage/*pharmacology ; Adult ; Biofilms/*drug effects ; Biomarkers/metabolism ; Corneal Ulcer/drug therapy/microbiology ; Double-Blind Method ; Enzyme-Linked Immunosorbent Assay ; Female ; Follow-Up Studies ; Humans ; Keratitis/drug therapy/*microbiology ; Male ; Middle Aged ; Polysaccharides/*metabolism ; Pseudomonas Infections/diagnosis/*drug therapy ; Pseudomonas aeruginosa/isolation & purification/*physiology ; Time Factors ; Treatment Outcome ; Visual Acuity ; }, abstract = {IMPORTANCE: Bacterial virulence factors are increasingly recognized as important in the understanding of clinical infections.

OBJECTIVE: To determine whether 2 potential virulence factors, in vitro biofilm formation and Psl exopolysaccharide (EPS) expression, influence clinical presentation or outcomes in Pseudomonas aeruginosa keratitis.

Laboratory investigation using P aeruginosa clinical isolates from the double-blind Steroids for Corneal Ulcers Trial (SCUT), which included patients at Aravind Eye Hospital, Proctor Foundation, University of California, San Francisco, and Dartmouth-Hitchcock Medical Center. SCUT was conducted from September 1, 2006, through February 22, 2010. All data used in this study were obtained during this period. Pseudomonas aeruginosa clinical isolates from SCUT were evaluated for in vitro biofilm formation, and Psl EPS expression was assessed using an anti-Psl monoclonal antibody (mAb) enzyme-linked immunosorbent assay. Planktonic growth kinetics and the susceptibility to anti-Psl mAb-mediated opsonophagocytic killing (OPK) were also evaluated in a subset of isolates. Linear regression assessed associations between SCUT patients' visual acuity and their corresponding biofilm formation and Psl EPS expression. Generalized estimating equation regression models were used to assess whether the change in visual acuity among SCUT patients was associated with Psl EPS expression or biofilm formation.

MAIN OUTCOMES AND MEASURES: Biofilm formation, Psl production, OPK, and visual acuity.

RESULTS: The P aeruginosa SCUT strains produced a mean (SD) in vitro biofilm score of 1.06 (0.32) (range 0.17-2.12). A 1-unit increase in biofilm was associated with a worse visual acuity of 2 lines measured in SCUT patients at baseline (0.20 logMAR; 95% CI, -0.03 to 0.44; P = .09) and 3 months (0.21 logMAR; 95% CI, 0.003 to 0.44; P = .047). Of 101 confirmed P aeruginosa SCUT isolates, 100 expressed Psl EPSs. In addition, all Psl-positive strains evaluated in the OPK assay were susceptible to anti-Psl mAb-mediated OPK.

CONCLUSIONS AND RELEVANCE: The ability of P aeruginosa keratitis isolates to form biofilms in vitro was correlated with worse vision at presentation and after 3 months in SCUT. Ninety-nine percent of P aeruginosa keratitis isolates from SCUT produced Psl EPSs, and 100% of these evaluated Psl-positive isolates were susceptible to anti-Psl mAb-mediated OPK. These data indicate that biofilm formation and Psl EPSs may be candidate targets for novel therapeutics against P aeruginosa keratitis.}, } @article {pmid26846044, year = {2015}, author = {Da Silva, S and Da Silva, EM and Delphim, MB and Poskus, LT and Amaral, CM}, title = {Influence of organic acids present in oral biofilm on the durability of the repair bond strength, sorption and solubility of resin composites.}, journal = {American journal of dentistry}, volume = {28}, number = {6}, pages = {367-372}, pmid = {26846044}, issn = {0894-8275}, mesh = {Absorption, Physicochemical ; Adsorption ; Aluminum Oxide/chemistry ; *Biofilms ; Bisphenol A-Glycidyl Methacrylate/chemistry ; Composite Resins/*chemistry ; *Dental Bonding ; Dental Etching/methods ; Dental Materials/*chemistry ; Humans ; Lactic Acid/*chemistry ; Materials Testing ; Methacrylates/chemistry ; Nanocomposites/chemistry ; Propionates/*chemistry ; Silorane Resins/chemistry ; Solubility ; Stress, Mechanical ; Surface Properties ; Temperature ; Tensile Strength ; Time Factors ; Water/chemistry ; }, abstract = {PURPOSE: To evaluate the repair bond strength after storage in water, lactic and propionic acid after 7 days and 6 months and the sorption and solubility of resin composites used.

METHODS: Five cylinders of each resin composite (microhybrid, nanofilled and silorane-based composite) were prepared. Specimens were aged with thermocycling (5 and 55°C) 5,000 times. A repair procedure was performed using intraoral sandblasting with 50-µm aluminum oxide, application of an adhesive system and cylinder of composite was fabricated. Specimens were sectioned into beams and stored in three immersion media: water, propionic acid and lactic acid. The microtensile bond strength was measured after periods of 7 days and 6 months. Sorption and solubility were evaluated using 15 specimens (0 = 6 mm; h = 1 mm) of each resin composite, which were prepared and assigned into three groups (n = 5) according to the immersion media (water, propionic acid and lactic acid). Data were analyzed using one-way/two-way/three-way ANOVA and Tukey's test (α = 0.05).

RESULTS: The resin composites, immersion media and time of immersion did not affect the repair bond strength (microhybrid 38.3 to 40.9 MPa; nanofilled 38.7 to 42.2 MPa; silorane 41.2 to 51.1 MPa). Additionally, the immersion media did not affect the sorption and solubility. The silorane-based composite presented the lowest sorption (10.5 to 12.1 µg/mm3) and solubility (-2.4 to -2.7 µg/mm3), while the nanofilled methacrylate-based composite showed the highest sorption (32.1 to 33.6 µg/mm3). Regarding solubility, the nanofilled and microhybrid methacrylate-based composites did not present statistically significant differences.}, } @article {pmid26846041, year = {2015}, author = {Hashizume, LN and Dariva, A}, title = {Effect of sonic vibration of an ultrasonic toothbrush on the removal of Streptococcus mutans biofilm from enamel surface.}, journal = {American journal of dentistry}, volume = {28}, number = {6}, pages = {347-350}, pmid = {26846041}, issn = {0894-8275}, mesh = {Bacterial Adhesion/physiology ; Bacterial Load ; *Biofilms ; Dental Enamel/*microbiology ; Dental Pellicle/microbiology ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Sonication ; Streptococcus mutans/*physiology ; Temperature ; Time Factors ; Toothbrushing/*instrumentation ; Ultrasonics/*instrumentation ; Vibration/*therapeutic use ; }, abstract = {PURPOSE: To evaluate in vitro the effect of sonic vibration of an ultrasonic toothbrush in the removal of Streptococcus mutans (S. mutans) biofilm from human enamel.

METHODS: S. mutans dental biofilm was formed in vitro on human enamel blocks coated by salivary pellicle. The blocks were incubated with a suspension of S. mutans at 37°C for 24 or 72 hours. The blocks were divided to one of three conditions according to the different toothbrush action modes: ultrasound plus sonic vibration (U+SV), ultrasound-only (U) and no ultrasound and no sonic vibration (control). Samples were exposed to each mode for 3 minutes with the toothbrush bristles placed 5 mm away from the enamel block surface. The samples were observed by scanning electron microscopy (SEM) and quantification of S. mutans was performed.

RESULTS: U+SV showed lower bacterial counts compared to U and control on the 72 hour-biofilm (P < 0.05). The SEM analysis revealed that U+SV and U disrupted the S. mutans chains in the 24- and 72-hour biofilm.}, } @article {pmid26846036, year = {2015}, author = {Cazzaniga, G and Ottobelli, M and Ionescu, A and Garcia-Godoy, F and Brambilla, E}, title = {Surface properties of resin-based composite materials and biofilm formation: A review of the current literature.}, journal = {American journal of dentistry}, volume = {28}, number = {6}, pages = {311-320}, pmid = {26846036}, issn = {0894-8275}, mesh = {Bacterial Adhesion/physiology ; *Biofilms ; Composite Resins/*chemistry ; Dental Materials/*chemistry ; Dental Plaque/microbiology ; Humans ; Materials Testing ; Surface Properties ; Surface Tension ; Wettability ; }, abstract = {PURPOSE: To evaluate the state of art on the relations between surface properties (surface roughness, topography, surface free energy and chemistry) of resin-based composite materials and microbial adhesion and biofilm formation.

METHODS: An electronic search using Scopus and PubMed (until May 2015) was conducted applying the following search items: "Plaque OR Biofilm AND Surface chemistry", "Plaque OR Biofilm AND Surface-free energy", "Plaque OR Biofilm AND Roughness", "Surface characteristics AND Composites", "Biofilm AND Surface characteristics".

RESULTS: Surface properties of resin-based composite materials as well as surface treatments can strongly affect bacterial adhesion and biofilm formation, although the "ideal" surface features have not been identified yet. Moreover, investigations highlighted that cariogenic biofilm formation may alter materials' surface properties, thus encouraging bacterial adhesion and biofilm formation, starting a "vicious cycle" which might compromise restoration longevity.}, } @article {pmid26845456, year = {2016}, author = {Mitzel, MR and Sand, S and Whalen, JK and Tufenkji, N}, title = {Hydrophobicity of biofilm coatings influences the transport dynamics of polystyrene nanoparticles in biofilm-coated sand.}, journal = {Water research}, volume = {92}, number = {}, pages = {113-120}, doi = {10.1016/j.watres.2016.01.026}, pmid = {26845456}, issn = {1879-2448}, mesh = {Biofilms/*growth & development ; Carboxylic Acids/chemistry ; *Hydrophobic and Hydrophilic Interactions ; Microspheres ; Nanoparticles/*chemistry ; Polystyrenes/*chemistry ; Pseudomonas aeruginosa/*physiology ; Silicon Dioxide/*chemistry ; Sulfates/chemistry ; }, abstract = {Engineered nanoparticles (ENPs) are used in the manufacture of over 2000 industrial and consumer products to enhance their material properties and functions or to enable new nanoparticle-dependent functions. The widespread use of ENPs will result in their release to the subsurface and aquatic environments, where they will interact with indigenous biota. Laboratory column experiments were designed to understand the influence of two different Pseudomonas aeruginosa biofilms on the mobility of polystyrene latex nanoparticles in granular porous media representative of groundwater aquifers or riverbank filtration settings. The transport behavior of 20 nm carboxylate-modified (CLPs) and sulfate (SLPs) polystyrene latex ENPs suspended in NaCl or CaCl2 (1 and 10 mM ionic strength, pH 7) was studied in columns packed with quartz sand coated with biofilms formed by two P. aeruginosa strains that differed in cell surface hydrophobicity (P. aeruginosa 9027™, relatively hydrophilic and P. aeruginosa PAO1, relatively hydrophobic). Biofilm-coated quartz sand retained more of the electrostatically-stabilized latex ENPs than clean, uncoated sand, regardless of the serotype. As IS increased, clear differences in the shape of the ENP breakthrough curves were observed for each type of biofilm coating. ENP breakthrough in the P. aeruginosa PAO1 biofilm-coated sand was generally constant with time whereby breakthrough in the P. aeruginosa 9027 biofilm-coated sand showed dynamic behavior. This indicates a fundamental difference in the mechanisms of ENP deposition onto hydrophilic or hydrophobic biofilm coatings due to the hydration properties of these biofilms. The results of this study demonstrate the importance of considering the surface properties of aquifer grain coatings when evaluating ENP fate in natural subsurface environments.}, } @article {pmid26841777, year = {2016}, author = {Chen, R and Luo, YH and Chen, JX and Zhang, Y and Wen, LL and Shi, LD and Tang, Y and Rittmann, BE and Zheng, P and Zhao, HP}, title = {Evolution of the microbial community of the biofilm in a methane-based membrane biofilm reactor reducing multiple electron acceptors.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {10}, pages = {9540-9548}, pmid = {26841777}, issn = {1614-7499}, mesh = {Archaea/metabolism ; Bacteria/genetics/metabolism ; Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/microbiology ; Denitrification ; Electrons ; Methane/*metabolism ; Nitrates/metabolism ; Nitrites/metabolism ; Oxidation-Reduction ; Perchlorates/metabolism ; Phylogeny ; }, abstract = {Previous work documented complete perchlorate reduction in a membrane biofilm reactor (MBfR) using methane as the sole electron donor and carbon source. This work explores how the biofilm's microbial community evolved as the biofilm stage-wise reduced different combinations of perchlorate, nitrate, and nitrite. The initial inoculum, carrying out anaerobic methane oxidation coupled to denitrification (ANMO-D), was dominated by uncultured Anaerolineaceae and Ferruginibacter sp. The microbial community significantly changed after it was inoculated into the CH4-based MBfR and fed with a medium containing perchlorate and nitrite. Archaea were lost within the first 40 days, and the uncultured Anaerolineaceae and Ferruginibacter sp. also had significant losses. Replacing them were anoxic methanotrophs, especially Methylocystis, which accounted for more than 25 % of total bacteria. Once the methanotrophs became important, methanol-oxidizing denitrifying bacteria, namely, Methloversatilis and Methylophilus, became important in the biofilm, probably by utilizing organic matter generated by the metabolism of methanotrophs. When methane consumption was equal to the maximum-possible electron-donor supply, Methylomonas, also an anoxic methanotroph, accounted for >10 % of total bacteria and remained a major part of the community until the end of the experiments. We propose that aerobic methane oxidation coupled to denitrification and perchlorate reduction (AMO-D and AMO-PR) directly oxidized methane and reduced NO3 (-) to NO2 (-) or N2O under anoxic condition, producing organic matter for methanol-assimilating denitrification and perchlorate reduction (MA-D and MA-PR) to reduce NO3 (-). Simultaneously, bacteria capable of anaerobic methane oxidation coupled to denitrification and perchlorate reduction (ANMO-D and ANMO-PR) used methane as the electron donor to respire NO3 (-) or ClO4 (-) directly. Graphical Abstract ᅟ.}, } @article {pmid26839888, year = {2015}, author = {Kayumov, AR and Nureeva, AA and Trizna, EY and Gazizova, GR and Bogachev, MI and Shtyrlin, NV and Pugachev, MV and Sapozhnikov, SV and Shtyrlin, YG}, title = {New Derivatives of Pyridoxine Exhibit High Antibacterial Activity against Biofilm-Embedded Staphylococcus Cells.}, journal = {BioMed research international}, volume = {2015}, number = {}, pages = {890968}, pmid = {26839888}, issn = {2314-6141}, mesh = {*Anti-Bacterial Agents/chemistry/pharmacology ; Biofilms/*drug effects/*growth & development ; *Pyridoxine/analogs & derivatives/chemistry/pharmacology ; Staphylococcus aureus/*physiology ; Staphylococcus epidermidis/*physiology ; }, abstract = {Opportunistic bacteria Staphylococcus aureus and Staphylococcus epidermidis often form rigid biofilms on tissues and inorganic surfaces. In the biofilm bacterial cells are embedded in a self-produced polysaccharide matrix and thereby are inaccessible to biocides, antibiotics, or host immune system. Here we show the antibacterial activity of newly synthesized cationic biocides, the quaternary ammonium, and bisphosphonium salts of pyridoxine (vitamin B6) against biofilm-embedded Staphylococci. The derivatives of 6-hydroxymethylpyridoxine were ineffective against biofilm-embedded S. aureus and S. epidermidis at concentrations up to 64 μg/mL, although all compounds tested exhibited low MICs (2 μg/mL) against planktonic cells. In contrast, the quaternary ammonium salt of pyridoxine (N,N-dimethyl-N-((2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridin-5-yl)methyl)octadecan-1-aminium chloride (3)) demonstrated high biocidal activity against both planktonic and biofilm-embedded bacteria. Thus, the complete death of biofilm-embedded S. aureus and S. epidermidis cells was obtained at concentrations of 64 and 16 μg/mL, respectively. We suggest that the quaternary ammonium salts of pyridoxine are perspective to design new synthetic antibiotics and disinfectants for external application against biofilm-embedded cells.}, } @article {pmid26838161, year = {2016}, author = {Cui, H and Li, W and Li, C and Vittayapadung, S and Lin, L}, title = {Liposome containing cinnamon oil with antibacterial activity against methicillin-resistant Staphylococcus aureus biofilm.}, journal = {Biofouling}, volume = {32}, number = {2}, pages = {215-225}, doi = {10.1080/08927014.2015.1134516}, pmid = {26838161}, issn = {1029-2454}, mesh = {Anti-Infective Agents/pharmacology ; *Biofilms/drug effects/growth & development ; *Cinnamomum zeylanicum ; Equipment Contamination/*prevention & control ; Equipment and Supplies, Hospital/microbiology ; Humans ; Liposomes/pharmacology ; *Methicillin-Resistant Staphylococcus aureus/drug effects/pathogenicity/physiology ; Microscopy, Electron, Scanning/methods ; Oils, Volatile/pharmacology ; }, abstract = {The global burden of bacterial disease remains high and is set against a backdrop of increasing antimicrobial resistance. There is a pressing need for highly effective and natural antibacterial agents. In this work, the anti-biofilm effect of cinnamon oil on methicillin-resistant Staphylococcus aureus was evaluated. Then, cinnamon oil was encapsulated in liposomes to enhance its chemical stability. The anti-biofilm activities of the liposome-encapsulated cinnamon oil against MRSA biofilms on stainless steel, gauze, nylon membrane and non-woven fabrics were evaluated by colony forming unit determination. Scanning electron microscopy and laser scanning confocal microscopy analyses were employed to observe the morphological changes in MRSA biofilms treated with the encapsulated cinnamon oil. As a natural and safe spice, the cinnamon oil exhibited a satisfactory antibacterial performance on MRSA and its biofilms. The application of liposomes further improves the stability of antimicrobial agents and extends the action time.}, } @article {pmid26837748, year = {2016}, author = {Khan, ST and Ahmad, J and Ahamed, M and Musarrat, J and Al-Khedhairy, AA}, title = {Zinc oxide and titanium dioxide nanoparticles induce oxidative stress, inhibit growth, and attenuate biofilm formation activity of Streptococcus mitis.}, journal = {Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry}, volume = {21}, number = {3}, pages = {295-303}, pmid = {26837748}, issn = {1432-1327}, mesh = {Anti-Bacterial Agents/chemical synthesis/chemistry/*pharmacology ; Biofilms/*drug effects ; Dose-Response Relationship, Drug ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry ; Oxidative Stress/*drug effects ; Streptococcus mitis/*drug effects/*growth & development/metabolism ; Structure-Activity Relationship ; Titanium/chemistry/*pharmacology ; Zinc Oxide/chemical synthesis/chemistry/*pharmacology ; }, abstract = {Streptococcus mitis from the oral cavity causes endocarditis and other systemic infections. Rising resistance against traditional antibiotics amongst oral bacteria further aggravates the problem. Therefore, antimicrobial and antibiofilm activities of zinc oxide and titanium dioxide nanoparticles (NPs) synthesized and characterized during this study against S. mitis ATCC 6249 and Ora-20 were evaluated in search of alternative antimicrobial agents. ZnO and TiO2-NPs exhibited an average size of 35 and 13 nm, respectively. The IC50 values of ZnO and TiO2-NPs against S. mitis ATCC 6249 were 37 and 77 µg ml(-1), respectively, while the IC50 values against S. mitis Ora-20 isolate were 31 and 53 µg ml(-1), respectively. Live and dead staining, biofilm formation on the surface of polystyrene plates, and extracellular polysaccharide production show the same pattern. Exposure to these nanoparticles also shows an increase (26-83 %) in super oxide dismutase (SOD) activity. Three genes, namely bapA1, sodA, and gtfB like genes from these bacteria were identified and sequenced for quantitative real-time PCR analysis. An increase in sodA gene (1.4- to 2.4-folds) levels and a decrease in gtfB gene (0.5- to 0.9-folds) levels in both bacteria following exposure to ZnO and TiO2-NPs were observed. Results presented in this study verify that ZnO-NPs and TiO2-NPs can control the growth and biofilm formation activities of these strains at very low concentration and hence can be used as alternative antimicrobial agents for oral hygiene.}, } @article {pmid26834732, year = {2016}, author = {Flores-Valdez, MA}, title = {Vaccines Directed Against Microorganisms or Their Products Present During Biofilm Lifestyle: Can We Make a Translation as a Broad Biological Model to Tuberculosis?.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {14}, pmid = {26834732}, issn = {1664-302X}, abstract = {Tuberculosis (TB) remains as a global public health problem. In recent years, experimental evidence suggesting the relevance of in vitro pellicle (a type of biofilm formed at the air-liquid interface) production as a phenotype mimicking aspects found by Mycobacterium tuberculosis-complex bacteria during in vivo infection has started to accumulate. There are still opportunities for better diagnostic tools, therapeutic molecules as well as new vaccine candidates to assist in TB control programs worldwide and particularly in less developed nations. Regarding vaccines, despite the availability of a live, attenuated strain (Mycobacterium bovis BCG) since almost a century ago, its variable efficacy and lack of protection against pulmonary and latent disease has prompted basic and applied research leading to preclinical and clinical evaluation of up to 15 new candidates. In this work, I present examples of vaccines based on whole cells grown as biofilms, or specific proteins expressed under such condition, and the effect they have shown in relevant animal models or directly in the natural host. I also discuss why it might be worthwhile to explore these approaches, for constructing and developing new vaccine candidates for testing their efficacy against TB.}, } @article {pmid26833157, year = {2016}, author = {Estellés, A and Woischnig, AK and Liu, K and Stephenson, R and Lomongsod, E and Nguyen, D and Zhang, J and Heidecker, M and Yang, Y and Simon, RJ and Tenorio, E and Ellsworth, S and Leighton, A and Ryser, S and Gremmelmaier, NK and Kauvar, LM}, title = {A High-Affinity Native Human Antibody Disrupts Biofilm from Staphylococcus aureus Bacteria and Potentiates Antibiotic Efficacy in a Mouse Implant Infection Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {4}, pages = {2292-2301}, pmid = {26833157}, issn = {1098-6596}, support = {R41 AI120425/AI/NIAID NIH HHS/United States ; }, mesh = {Amino Acid Sequence ; Animals ; Anti-Bacterial Agents/biosynthesis/isolation & purification/*pharmacology ; Antibodies, Monoclonal/biosynthesis/isolation & purification/*pharmacology ; Antibody Specificity ; B-Lymphocytes/chemistry/cytology/immunology ; Bacterial Proteins/antagonists & inhibitors/genetics/metabolism ; Biofilms/*drug effects/growth & development ; DNA-Binding Proteins/antagonists & inhibitors/genetics/metabolism ; Daptomycin/pharmacology ; Disease Models, Animal ; Drug Therapy, Combination ; Epitope Mapping ; Female ; Foreign Bodies/*drug therapy/microbiology ; Gene Expression ; Injections, Intraperitoneal ; Integration Host Factors/antagonists & inhibitors/genetics/metabolism ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/growth & development/metabolism ; Mice ; Mice, Inbred C57BL ; Models, Molecular ; Plankton/drug effects/genetics/growth & development/metabolism ; Sequence Alignment ; Single-Cell Analysis ; Staphylococcal Infections/*drug therapy/microbiology ; }, abstract = {Many serious bacterial infections are difficult to treat due to biofilm formation, which provides physical protection and induces a sessile phenotype refractory to antibiotic treatment compared to the planktonic state. A key structural component of biofilm is extracellular DNA, which is held in place by secreted bacterial proteins from the DNABII family: integration host factor (IHF) and histone-like (HU) proteins. A native human monoclonal antibody, TRL1068, has been discovered using single B-lymphocyte screening technology. It has low-picomolar affinity against DNABII homologs from important Gram-positive and Gram-negative bacterial pathogens. The disruption of established biofilm was observedin vitroat an antibody concentration of 1.2 μg/ml over 12 h. The effect of TRL1068in vivowas evaluated in a murine tissue cage infection model in which a biofilm is formed by infection with methicillin-resistantStaphylococcus aureus(MRSA; ATCC 43300). Treatment of the established biofilm by combination therapy of TRL1068 (15 mg/kg of body weight, intraperitoneal [i.p.] administration) with daptomycin (50 mg/kg, i.p.) significantly reduced adherent bacterial count compared to that after daptomycin treatment alone, accompanied by significant reduction in planktonic bacterial numbers. The quantification of TRL1068 in sample matrices showed substantial penetration of TRL1068 from serum into the cage interior. TRL1068 is a clinical candidate for combination treatment with standard-of-care antibiotics to overcome the drug-refractory state associated with biofilm formation, with potential utility for a broad spectrum of difficult-to-treat bacterial infections.}, } @article {pmid26833153, year = {2016}, author = {Hengzhuang, W and Song, Z and Ciofu, O and Onsøyen, E and Rye, PD and Høiby, N}, title = {OligoG CF-5/20 Disruption of Mucoid Pseudomonas aeruginosa Biofilm in a Murine Lung Infection Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {5}, pages = {2620-2626}, pmid = {26833153}, issn = {1098-6596}, mesh = {Animals ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; Colistin/*pharmacology ; Female ; Interleukin-1alpha/metabolism ; Mice ; Mice, Inbred BALB C ; Microbial Sensitivity Tests ; Pseudomonas Infections/metabolism/microbiology ; Pseudomonas aeruginosa/*drug effects/metabolism ; }, abstract = {Biofilm growth is a universal survival strategy for bacteria, providing an effective and resilient approach for survival in an otherwise hostile environment. In the context of an infection, a biofilm provides resistance and tolerance to host immune defenses and antibiotics, allowing the biofilm population to survive and thrive under conditions that would destroy their planktonic counterparts. Therefore, the disruption of the biofilm is a key step in eradicating persistent bacterial infections, as seen in many types of chronic disease. In these studies, we used both in vitro minimum biofilm eradication concentration (MBEC) assays and an in vivo model of chronic biofilm infection to demonstrate the biofilm-disrupting effects of an alginate oligomer, OligoG CF-5/20. Biofilm infections were established in mice by tracheal instillation of a mucoid clinical isolate of Pseudomonas aeruginosa embedded in alginate polymer beads. The disruption of the biofilm by OligoG CF-5/20 was observed in a dose-dependent manner over 24 h, with up to a 2.5-log reduction in CFU in the infected mouse lungs. Furthermore, in vitro assays showed that 5% OligoG CF-5/20 significantly reduced the MBEC for colistin from 512 μg/ml to 4 μg/ml after 8 h. These findings support the potential for OligoG CF-5/20 as a biofilm disruption agent which may have clinical value in reducing the microbial burden in chronic biofilm infections.}, } @article {pmid26832663, year = {2016}, author = {Kim, SK and Lee, JH}, title = {Biofilm dispersion in Pseudomonas aeruginosa.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {54}, number = {2}, pages = {71-85}, pmid = {26832663}, issn = {1976-3794}, mesh = {Biofilms/*growth & development ; Environmental Exposure ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*physiology ; }, abstract = {In recent decades, many researchers have written numerous articles about microbial biofilms. Biofilm is a complex community of microorganisms and an example of bacterial group behavior. Biofilm is usually considered a sessile mode of life derived from the attached growth of microbes to surfaces, and most biofilms are embedded in self-produced extracellular matrix composed of extracellular polymeric substances (EPSs), such as polysaccharides, extracellular DNAs (eDNA), and proteins. Dispersal, a mode of biofilm detachment indicates active mechanisms that cause individual cells to separate from the biofilm and return to planktonic life. Since biofilm cells are cemented and surrounded by EPSs, dispersal is not simple to do and many researchers are now paying more attention to this active detachment process. Unlike other modes of biofilm detachment such as erosion or sloughing, which are generally considered passive processes, dispersal occurs as a result of complex spatial differentiation and molecular events in biofilm cells in response to various environmental cues, and there are many biological reasons that force bacterial cells to disperse from the biofilms. In this review, we mainly focus on the spatial differentiation of biofilm that is a prerequisite for dispersal, as well as environmental cues and molecular events related to the biofilm dispersal. More specifically, we discuss the dispersal-related phenomena and mechanisms observed in Pseudomonas aeruginosa, an important opportunistic human pathogen and representative model organism for biofilm study.}, } @article {pmid26831479, year = {2016}, author = {Urish, KL and DeMuth, PW and Kwan, BW and Craft, DW and Ma, D and Haider, H and Tuan, RS and Wood, TK and Davis, CM}, title = {Antibiotic-tolerant Staphylococcus aureus Biofilm Persists on Arthroplasty Materials.}, journal = {Clinical orthopaedics and related research}, volume = {474}, number = {7}, pages = {1649-1656}, pmid = {26831479}, issn = {1528-1132}, support = {KL2 TR000146/TR/NCATS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Arthroplasty, Replacement, Knee/*adverse effects/instrumentation ; Bacterial Proteins/genetics/metabolism ; Bacterial Toxins/genetics/metabolism ; Biofilms/*drug effects/growth & development ; Cefazolin/*pharmacology ; Dose-Response Relationship, Drug ; *Drug Resistance, Bacterial/genetics ; Endoribonucleases/genetics/metabolism ; Knee Prosthesis/*adverse effects/microbiology ; Methicillin/pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Microscopy, Confocal ; Phenotype ; Prosthesis Design ; Prosthesis-Related Infections/diagnosis/*drug therapy/microbiology ; Staphylococcal Infections/diagnosis/*drug therapy/microbiology ; Staphylococcus aureus/*drug effects/genetics/growth & development/metabolism ; }, abstract = {BACKGROUND: The continued presence of biofilm may be one cause of the high risk of failure observed with irrigation and débridement with component retention in acute periprosthetic joint infection (PJI). There is a poor understanding of the role of biofilm antibiotic tolerance in PJI.

QUESTIONS/PURPOSES: (1) Do increasing doses of cefazolin result in decreased viable biofilm mass on arthroplasty materials? (2) Is cefazolin resistance phenotypic or genotypic? (3) Is biofilm viability a function of biofilm depth after treatment with cefazolin? (4) Is the toxin-antitoxin system, yoeB expression, associated with antibiotic stress?

METHODS: Methicillin-sensitive Staphylococcus aureus biofilm was cultured on total knee arthroplasty (TKA) materials and exposed to increasing doses of cefazolin (control, 0.5, 1.0, 10.0, 100.0 μg/mL). Quantitative confocal microscopy and quantitative culture were used to measure viable biofilm cell density. To determine if cefazolin resistance was phenotypic or genotypic, we measured minimum inhibitory concentration (MIC) after exposure to different cefazolin concentrations; changes in MIC would suggest genotypic features, whereas unchanged MIC would suggest phenotypic behavior. Finally, quantitative reverse transcription-polymerase chain reaction was used to quantify expression of yoeB levels between biofilm and planktonic bacteria after exposure to 1 μg/mL cefazolin for 3 hours.

RESULTS: Although live biofilm mass was reduced by exposure to cefazolin when compared with biofilm mass in controls (39.2 × 10(3) ± 26.4 × 10(3) pixels), where the level after 0.5 µg/mL exposure also showed reduced mass (20.3 × 10(3) ± 11.9 × 10(3) pixels), no further reduction was seen after higher doses (mass at 1.0 µg/mL: 5.0 × 10(3) pixels ± 1.1 × 10(3) pixels; at 10.0 µg/mL: 6.4 × 10(3) ± 9.6 × 10(3) pixels; at 100.0 µg/mL: 6.4 × 10(3) ± 3.9 × 10(3)). At the highest concentration tested (100 µg/mL), residual viable biofilm was present on all three materials, and there were no differences in percent biofilm survival among cobalt-chromium (18.5% ± 15.1%), polymethylmethacrylate (22.8% ± 20.2%), and polyethylene (14.7% ± 10.4%). We found that tolerance was a phenotypic phenomenon, because increasing cefazolin exposure did not result in changes in MIC as compared with controls (MIC in controls: 0.13 ± 0.02; at 0.5 µg/mL: 0.13 ± 0.001, p = 0.96; at 1.0 µg/m: 0.14 ± 0.04, p = 0.95; at 10.0 µg/m: 0.11 ± 0.016, p = 0.47; at 100.0 µg/m: 0.94 ± 0.047, p = 0.47). Expression of yoeB after 1 µg/mL cefazolin for 3 hours in biofilm cells was greater in biofilm but not in planktonic cells (biofilm: 62.3-fold change, planktonic cells: -78.8-fold change, p < 0.001).

CONCLUSIONS: Antibiotics are inadequate at complete removal of the biofilm from the surface of TKA materials. Results suggest that bacterial persisters are responsible for this phenotypic behavior allowing biofilm high tolerance to antibiotics.

CLINICAL RELEVANCE: Antibiotic-tolerant biofilm suggests a mechanism behind the poor results in irrigation and débridement for acute TKA PJI.}, } @article {pmid26830428, year = {2016}, author = {Pladisai, P and Ampornaramveth, RS and Chivatxaranukul, P}, title = {Effectiveness of Different Disinfection Protocols on the Reduction of Bacteria in Enterococcus faecalis Biofilm in Teeth with Large Root Canals.}, journal = {Journal of endodontics}, volume = {42}, number = {3}, pages = {460-464}, doi = {10.1016/j.joen.2015.12.016}, pmid = {26830428}, issn = {1878-3554}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Dental Pulp Cavity/*microbiology ; Disinfection/*methods ; Enterococcus faecalis/*drug effects/*physiology ; Humans ; Microbial Sensitivity Tests ; Root Canal Irrigants/*pharmacology ; Root Canal Preparation/instrumentation/methods ; Root Canal Therapy/methods ; Sodium Chloride/pharmacology ; Sodium Hypochlorite/pharmacology ; Therapeutic Irrigation/methods ; Ultrasonic Therapy ; }, abstract = {INTRODUCTION: This study compared the effectiveness of different disinfection protocols in reducing bacteria in an Enterococcus faecalis biofilm in teeth with large root canals.

METHODS: Fifty-five roots were prepared from human mandibular premolars with large single root canals, and 50 roots were infected with E. faecalis for 21 days. Four roots were observed using scanning electron microscopy to verify biofilm formation. The remaining specimens were assigned into 5 experimental groups and a sterile control group: mechanical instrumentation using files size 60-90 and 2.5% sodium hypochlorite (NaOCl) (MI-N), irrigation with 2.5% NaOCl (IR-N), irrigation with 2.5% NaOCl using intermittent passive ultrasonic irrigation (PUI-N), irrigation with normal saline, and no intervention (initial). After root canal disinfection, dentin specimens were collected for microbial analysis. Mean colony forming units were determined and compared between groups using 1-way analysis of variance.

RESULTS: The lowest number of intracanal bacteria (24.5 colony-forming units/mL) was recovered from the MI-N group followed by the PUI-N and IR-N groups. The irrigation with normal saline group did not show a significant reduction compared with the initial group. However, there were significant differences between groups (P < .01). The remaining bacteria in the PUI-N group was 4.5-fold lower compared with the IR-N group; however, it was 1862-fold higher compared with the MI-N group.

CONCLUSIONS: MI-N was the most effective method to disinfect large root canals. Although ultrasonic activation enhanced the efficacy of root canal irrigation, it could not substitute for mechanical instrumentation even in large root canals with unlimited irrigant access to the apical portion.}, } @article {pmid26829529, year = {2016}, author = {Wang, Z and Gao, M and Wei, J and Ma, K and Zhang, J and Yang, Y and Yu, S}, title = {Extracellular polymeric substances, microbial activity and microbial community of biofilm and suspended sludge at different divalent cadmium concentrations.}, journal = {Bioresource technology}, volume = {205}, number = {}, pages = {213-221}, doi = {10.1016/j.biortech.2016.01.067}, pmid = {26829529}, issn = {1873-2976}, mesh = {Biofilms/*drug effects/growth & development ; Bioreactors/*microbiology ; Cadmium/*toxicity ; Microbial Consortia/drug effects/*physiology ; Nitrates/chemistry/metabolism ; Nitrites/metabolism ; Nitrogen/metabolism ; Oxidation-Reduction ; Polysaccharides/metabolism ; Sewage/microbiology ; Waste Disposal, Fluid/instrumentation/*methods ; Water Pollutants, Chemical/toxicity ; }, abstract = {The differences between biofilm and suspended sludge (S-sludge) in extracellular polymeric substances (EPS), microbial activity, and microbial community in an anoxic-aerobic sequencing batch biofilm reactor (SBBR) at different concentrations of divalent cadmium (Cd(II)) were investigated. As the increase of Cd(II) concentration from 0 to 50mgL(-1), the specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) of biofilm decreased from 4.85, 5.22 and 45mgNg(-1) VSSh(-1) to 1.54, 2.38 and 26mgNg(-1)VSSh(-1), respectively, and the SAOR, SNOR and SNRR of S-sludge decreased from 4.80, 5.02 and 34mgNg(-1)VSSh(-1) to 1.46, 2.20 and 17mgNg(-1)VSSh(-1), respectively. Biofilm had higher protein (PN) content in EPS than S-sludge. Contrast to S-sludge, biofilm could provide Nitrobacter vulgaris, beta proteobacterium INBAF015, and Pseudoxanthomonas mexicana with the favorable conditions of growth and reproduction.}, } @article {pmid26829486, year = {2016}, author = {Bland, DM and Hinnebusch, BJ}, title = {Feeding Behavior Modulates Biofilm-Mediated Transmission of Yersinia pestis by the Cat Flea, Ctenocephalides felis.}, journal = {PLoS neglected tropical diseases}, volume = {10}, number = {2}, pages = {e0004413}, pmid = {26829486}, issn = {1935-2735}, support = {//Intramural NIH HHS/United States ; }, mesh = {Animals ; Ctenocephalides/*microbiology/*physiology ; Feeding Behavior ; Female ; Gastrointestinal Tract/microbiology ; Humans ; Insect Vectors/*microbiology/*physiology ; Male ; Plague/microbiology/*transmission ; Sheep ; Yersinia pestis/*physiology ; }, abstract = {BACKGROUND: The cat flea, Ctenocephalides felis, is prevalent worldwide, will parasitize animal reservoirs of plague, and is associated with human habitations in known plague foci. Despite its pervasiveness, limited information is available about the cat flea's competence as a vector for Yersinia pestis. It is generally considered to be a poor vector, based on studies examining early-phase transmission during the first week after infection, but transmission potential by the biofilm-dependent proventricular-blocking mechanism has never been systematically evaluated. In this study, we assessed the vector competence of cat fleas by both mechanisms. Because the feeding behavior of cat fleas differs markedly from important rat flea vectors, we also examined the influence of feeding behavior on transmission dynamics.

Groups of cat fleas were infected with Y. pestis and subsequently provided access to sterile blood meals twice-weekly, 5 times per week, or daily for 4 weeks and monitored for infection, the development of proventricular biofilm and blockage, mortality, and the ability to transmit. In cat fleas allowed prolonged, daily access to blood meals, mimicking their natural feeding behavior, Y. pestis did not efficiently colonize the digestive tract and could only be transmitted during the first week after infection. In contrast, cat fleas that were fed intermittently, mimicking the feeding behavior of the efficient vector Xenopsylla cheopis, could become blocked and regularly transmitted Y. pestis for 3-4 weeks by the biofilm-mediated mechanism, but early-phase transmission was not detected.

CONCLUSIONS: The normal feeding behavior of C. felis, more than an intrinsic resistance to infection or blockage by Y. pestis, limits its vector competence. Rapid turnover of midgut contents results in bacterial clearance and disruption of biofilm accumulation in the proventriculus. Anatomical features of the cat flea foregut may also restrict transmission by both early-phase and proventricular biofilm-dependent mechanisms.}, } @article {pmid26829048, year = {2016}, author = {Gerrity, S and Kennelly, C and Clifford, E and Collins, G}, title = {Hydrogen sulfide oxidation in novel Horizontal-Flow Biofilm Reactors dominated by an Acidithiobacillus and a Thiobacillus species.}, journal = {Environmental technology}, volume = {37}, number = {17}, pages = {2252-2264}, doi = {10.1080/09593330.2016.1147609}, pmid = {26829048}, issn = {1479-487X}, mesh = {Acidithiobacillus/genetics/*metabolism ; *Biofilms ; Bioreactors/*microbiology ; Hydrogen Sulfide/analysis/*chemistry ; Oxidation-Reduction ; Thiobacillus/genetics/*metabolism ; }, abstract = {Hydrogen Sulfide (H2S) is an odourous, highly toxic gas commonly encountered in various commercial and municipal sectors. Three novel, laboratory-scale, Horizontal-Flow Biofilm Reactors (HFBRs) were tested for the removal of H2S gas from air streams over a 178-day trial at 10°C. Removal rates of up to 15.1 g [H2S] m(-3) h(-1) were achieved, demonstrating the HFBRs as a feasible technology for the treatment of H2S-contaminated airstreams at low temperatures. Bio-oxidation of H2S in the reactors led to the production of H(+) and sulfate (SO(2-)4) ions, resulting in the acidification of the liquid phase. Reduced removal efficiency was observed at loading rates of 15.1 g [H2S] m(-3) h(-1). NaHCO3 addition to the liquid nutrient feed (synthetic wastewater (SWW)) resulted in improved H2S removal. Bacterial diversity, which was investigated by sequencing and fingerprinting 16S rRNA genes, was low, likely due to the harsh conditions prevailing in the systems. The HFBRs were dominated by two species from the genus Acidithiobacillus and Thiobacillus. Nonetheless, there were significant differences in microbial community structure between distinct HFBR zones due to the influence of alkalinity, pH and SO4 concentrations. Despite the low temperature, this study indicates HFBRs have an excellent potential to biologically treat H2S-contaminated airstreams.}, } @article {pmid26826978, year = {2016}, author = {Petrova, OE and Sauer, K}, title = {Escaping the biofilm in more than one way: desorption, detachment or dispersion.}, journal = {Current opinion in microbiology}, volume = {30}, number = {}, pages = {67-78}, pmid = {26826978}, issn = {1879-0364}, support = {R01 AI075257/AI/NIAID NIH HHS/United States ; R01 AI080710/AI/NIAID NIH HHS/United States ; R01A10752570//PHS HHS/United States ; R01AI080710/AI/NIAID NIH HHS/United States ; }, mesh = {Bacteria/chemistry/genetics/growth & development ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Gene Expression Regulation, Bacterial ; }, abstract = {Biofilm bacteria have developed escape strategies to avoid stresses associated with biofilm growth, respond to changing environmental conditions, and disseminate to new locations. An ever-expanding body of research suggests that cellular release from biofilms is distinct from a simple reversal of attachment and reversion to a planktonic mode of growth, with biofilm dispersion involving sensing of specific cues, regulatory signal transduction, and consequent physiological alterations. However, dispersion is only one of many ways to escape the biofilm mode of growth. The present review is aimed at distinguishing this active and regulated process of dispersion from the passive processes of desorption and detachment by highlighting the regulatory processes and distinct phenotypes specific to dispersed cells.}, } @article {pmid26826023, year = {2016}, author = {Long, TE and Keding, LC and Lewis, DD and Anstead, MI and Withers, TR and Yu, HD}, title = {Anionic fluoroquinolones as antibacterials against biofilm-producing Pseudomonas aeruginosa.}, journal = {Bioorganic & medicinal chemistry letters}, volume = {26}, number = {4}, pages = {1305-1309}, pmid = {26826023}, issn = {1464-3405}, support = {P20 GM103434/GM/NIGMS NIH HHS/United States ; UL1 TR000117/TR/NCATS NIH HHS/United States ; P20GM103434/GM/NIGMS NIH HHS/United States ; UL1TR000117/TR/NCATS NIH HHS/United States ; }, mesh = {Anions/chemistry ; Anti-Bacterial Agents/chemical synthesis/*chemistry/pharmacology ; Biofilms/drug effects ; Fluoroquinolones/chemical synthesis/*chemistry/pharmacology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*physiology ; }, abstract = {Pseudomonas aeruginosa is a common biofilm-forming bacterial pathogen implicated in diseases of the lungs. The extracellular polymeric substances (EPS) of respiratory Pseudomonas biofilms are largely comprised of anionic molecules such as rhamnolipids and alginate that promote a mucoid phenotype. In this Letter, we examine the ability of negatively-charged fluoroquinolones to transverse the EPS and inhibit the growth of mucoid P. aeruginosa. Anionic fluoroquinolones were further compared with standard antibiotics via a novel microdiffusion assay to evaluate drug penetration through pseudomonal alginate and respiratory mucus from a patient with cystic fibrosis.}, } @article {pmid26825521, year = {2016}, author = {Benedek, T and Táncsics, A and Szabó, I and Farkas, M and Szoboszlay, S and Fábián, K and Maróti, G and Kriszt, B}, title = {Polyphasic analysis of an Azoarcus-Leptothrix-dominated bacterial biofilm developed on stainless steel surface in a gasoline-contaminated hypoxic groundwater.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {9}, pages = {9019-9035}, pmid = {26825521}, issn = {1614-7499}, mesh = {Azoarcus/*physiology ; Bacteria/metabolism ; Biodegradation, Environmental ; Biofilms ; Carbon-Carbon Lyases ; Gasoline/*analysis/microbiology ; Groundwater/*chemistry ; Hydrocarbons/metabolism ; Hydrocarbons, Aromatic/metabolism ; Leptothrix/*physiology ; Phylogeny ; Stainless Steel/*chemistry ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Pump and treat systems are widely used for hydrocarbon-contaminated groundwater remediation. Although biofouling (formation of clogging biofilms on pump surfaces) is a common problem in these systems, scarce information is available regarding the phylogenetic and functional complexity of such biofilms. Extensive information about the taxa and species as well as metabolic potential of a bacterial biofilm developed on the stainless steel surface of a pump submerged in a gasoline-contaminated hypoxic groundwater is presented. Results shed light on a complex network of interconnected hydrocarbon-degrading chemoorganotrophic and chemolitotrophic bacteria. It was found that besides the well-known hydrocarbon-degrading aerobic/facultative anaerobic biofilm-forming organisms (e.g., Azoarcus, Leptothrix, Acidovorax, Thauera, Pseudomonas, etc.), representatives of Fe(2+)-and Mn(2+)-oxidizing (Thiobacillus, Sideroxydans, Gallionella, Rhodopseudomonas, etc.) as well as of Fe(3+)- and Mn(4+)-respiring (Rhodoferax, Geobacter, Magnetospirillum, Sulfurimonas, etc.) bacteria were present in the biofilm. The predominance of β-Proteobacteria within the biofilm bacterial community in phylogenetic and functional point of view was revealed. Investigation of meta-cleavage dioxygenase and benzylsuccinate synthase (bssA) genes indicated that within the biofilm, Azoarcus, Leptothrix, Zoogloea, and Thauera species are most probably involved in intrinsic biodegradation of aromatic hydrocarbons. Polyphasic analysis of the biofilm shed light on the fact that subsurface microbial accretions might be reservoirs of novel putatively hydrocarbon-degrading bacterial species. Moreover, clogging biofilms besides their detrimental effects might supplement the efficiency of pump and treat systems.}, } @article {pmid26824954, year = {2016}, author = {Atwood, DN and Beenken, KE and Lantz, TL and Meeker, DG and Lynn, WB and Mills, WB and Spencer, HJ and Smeltzer, MS}, title = {Regulatory Mutations Impacting Antibiotic Susceptibility in an Established Staphylococcus aureus Biofilm.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {3}, pages = {1826-1829}, pmid = {26824954}, issn = {1098-6596}, support = {UL1 TR000039/TR/NCATS NIH HHS/United States ; UL1TR000039/TR/NCATS NIH HHS/United States ; R01-AI119380/AI/NIAID NIH HHS/United States ; R01 AI119380/AI/NIAID NIH HHS/United States ; P30 GM103450/GM/NIGMS NIH HHS/United States ; P20 GM103625/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/drug therapy/microbiology ; Catheters/microbiology ; Cephalosporins/*pharmacology ; Daptomycin/*pharmacology ; Drug Resistance, Bacterial/genetics ; Humans ; Mice ; Microbial Sensitivity Tests ; Sigma Factor/*genetics ; Staphylococcal Infections/drug therapy ; Staphylococcus aureus/*drug effects/*genetics/isolation & purification/pathogenicity ; }, abstract = {We previously determined the extent to which mutations of different Staphylococcus aureus regulatory loci impact biofilm formation as assessed under in vitro conditions. Here we extend these studies to determine the extent to which those regulatory loci that had the greatest effect on biofilm formation also impact antibiotic susceptibility. The experiments were done under in vitro and in vivo conditions using two clinical isolates of S. aureus (LAC and UAMS-1) and two functionally diverse antibiotics (daptomycin and ceftaroline). Mutation of the staphylococcal accessory regulator (sarA) or sigB was found to significantly increase susceptibilities to both antibiotics and in both strains in a manner that could not be explained by changes in the MICs. The impact of a mutation in sarA was comparable to that of a mutation in sigB and greater than the impact observed with any other mutant. These results suggest that therapeutic strategies targeting sarA and/or sigB have the greatest potential to facilitate the ability to overcome the intrinsic antibiotic resistance that defines S. aureus biofilm-associated infections.}, } @article {pmid26821356, year = {2016}, author = {Comin, VM and Lopes, LQ and Quatrin, PM and de Souza, ME and Bonez, PC and Pintos, FG and Raffin, RP and Vaucher, Rde A and Martinez, DS and Santos, RC}, title = {Influence of Melaleuca alternifolia oil nanoparticles on aspects of Pseudomonas aeruginosa biofilm.}, journal = {Microbial pathogenesis}, volume = {93}, number = {}, pages = {120-125}, doi = {10.1016/j.micpath.2016.01.019}, pmid = {26821356}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/chemistry/*pharmacology ; Bacterial Adhesion/drug effects ; Bacterial Proteins/genetics/metabolism ; Biofilms/*drug effects ; Epithelial Cells/microbiology ; Humans ; Melaleuca/*chemistry ; Microbial Sensitivity Tests ; Mouth Mucosa/microbiology ; Nanoparticles/chemistry/*toxicity ; Pseudomonas Infections/microbiology ; Pseudomonas aeruginosa/*drug effects/genetics/physiology ; Tea Tree Oil/chemistry/*pharmacology ; Virulence Factors/genetics/metabolism ; }, abstract = {The Pseudomonas aeruginosa is a gram-negative bacillus and frequent cause of infection. This microorganism is resistant intrinsically to various drugs. The P. aeruginosa is associated with the biofilm formation, which causes worsen the prognosis and difficulty the treatment. The influence of Melaleuca alternifolia oil or "tree of tee" oil (TTO) and TTO nanoparticles on adhesion of P. aeruginosa in buccal epithelial cells was investigated. Also was determined the antimicrobial and antibiofilm activity against this microorganism. The TTO nanoparticles were produced by deposition of preformed polymer and the physic-chemical properties of nanoparticles were measured by electrophoresis and dynamic light scattering. The characterization of nanoparticle showed acceptable values for diameter and zeta potential. The evaluation of antimicrobial and antibiofilm activity against P. aeruginosa PAO1 was performed by microdilution indicating the minimal inhibitory concentration, and the potential antibiofilm. It was verified the action on virulence factors such the motility, besides the influence on adhesion in buccal epithelial cells. Both oil and nanoparticles showed a decrease in adhesion of microorganisms to buccal cells, decrease of biofilm and interfering on P. aeruginosa PAO1 motility. The nanostructuration of TTO, shows be a viable alternative against formed biofilm microorganisms.}, } @article {pmid26821355, year = {2016}, author = {Soroush, S and Jabalameli, F and Taherikalani, M and Amirmozafari, N and Fooladi, AA and Asadollahi, K and Beigverdi, R and Emaneini, M}, title = {Investigation of biofilm formation ability, antimicrobial resistance and the staphylococcal cassette chromosome mec patterns of methicillin resistant Staphylococcus epidermidis with different sequence types isolated from children.}, journal = {Microbial pathogenesis}, volume = {93}, number = {}, pages = {126-130}, doi = {10.1016/j.micpath.2016.01.018}, pmid = {26821355}, issn = {1096-1208}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*drug effects ; Child ; Child, Preschool ; Cross-Sectional Studies ; Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Infant ; Iran ; Male ; Methicillin/pharmacology ; Methicillin-Resistant Staphylococcus aureus/classification/drug effects/*isolation & purification/*physiology ; Multilocus Sequence Typing ; Operon ; Recombinases/*genetics/metabolism ; Staphylococcal Infections/*microbiology ; Staphylococcus epidermidis/classification/*drug effects/genetics/physiology ; }, abstract = {This study investigated the molecular characterizations of 80 methicillin resistant Staphylococcus epidermidis (MRSE) collected during 2012-2013 in Tehran Children's Medical Center, Iran. About 90% of MRSE isolates were multi-drug resistant (MDR) and the highest resistance was observed to cotrimoxazole and they were quite sensitive to quinupristin-dalfopristin and linezolid. Though vanA gene was not detected, the majority of isolates showed intermediate resistance to vancomycin (MIC90 16 μg/ml). Resistance to mupirocin was observed in 18 isolates. Staphylococcal cassette chromosome mec (SCCmec) types V, III, IV and II were detected in 23.75%, 7.5%, 6.25% and 5% of isolates respectively, in some of which the additional parts of mec or ccr complexes were observed. In 57.5% MRSE isolates SCCmec types were not classified. 41.2% of MRSE isolates were carrying intercellular adhesion (ica) operon and 40% had strong or intermediate biofilm. The types of arginine catabolic mobile element (ACME) were limited to type I and II. Nine sequence types (STs) were seen in mupirocin resistant MRSE isolates. The common STs were ST2, ST5 and ST22 with 27.7% (5/18), 22.2% (4/18) and 16.6% (3/18) frequencies, respectively. ST23, ST54 and ST179 plus three novels STs 580, 581,588 were also observed. The majority of STs, 83.3% (15/18) belonged to clonal complex 2 (CC2). The spread of antibiotic resistance and virulence factors among MRSE species is an alarming sign in Children's Hospitals. The combination of these two issues leads to increase the chance of successfully establishing of common STs in hospital environments, and promotes the device-related infections and bacteremia.}, } @article {pmid26819677, year = {2016}, author = {Mishra, B and Golla, RM and Lau, K and Lushnikova, T and Wang, G}, title = {Anti-Staphylococcal Biofilm Effects of Human Cathelicidin Peptides.}, journal = {ACS medicinal chemistry letters}, volume = {7}, number = {1}, pages = {117-121}, pmid = {26819677}, issn = {1948-5875}, support = {R01 AI105147/AI/NIAID NIH HHS/United States ; }, abstract = {Staphylococcus aureus can live together in the form of biofilms to avoid elimination by the host. Thus, a useful strategy to counteract bacterial biofilms is to re-engineer human antimicrobial peptide LL-37 so that it can be used as a remedy for preventing and removing biofilms. This study reports antibiofilm effects of four human cathelicidin LL-37 peptides against community-associated and hospital isolated methicillin-resistant Staphylococcus aureus (MRSA) strains. Although the intact molecule LL-37 inhibited biofilm formation at low concentrations, it did not inhibit bacterial attachment nor disrupt preformed biofilms. However, two 17-residue peptides, GF-17 and 17BIPHE2, inhibited bacterial attachment, biofilm growth, and disrupted established biofilms. An inactive peptide RI-10 was used as a negative control. Our results obtained using the S. aureus mutants in a static biofilm model are consistent with the literature obtained in a flow cell biofilm model. Because 17BIPHE2 is the most effective biofilm disruptor with desired stability to proteases, it is a promising lead for developing new anti-MRSA biofilm agents.}, } @article {pmid26819559, year = {2015}, author = {Aggarwal, S and Stewart, PS and Hozalski, RM}, title = {Biofilm Cohesive Strength as a Basis for Biofilm Recalcitrance: Are Bacterial Biofilms Overdesigned?.}, journal = {Microbiology insights}, volume = {8}, number = {Suppl 2}, pages = {29-32}, pmid = {26819559}, issn = {1178-6361}, abstract = {Bacterial biofilms are highly resistant to common antibacterial treatments, and several physiological explanations have been offered to explain the recalcitrant nature of bacterial biofilms. Herein, a biophysical aspect of biofilm recalcitrance is being reported on. While engineering structures are often overdesigned with a factor of safety (FOS) usually under 10, experimental measurements of biofilm cohesive strength suggest that the FOS is on the order of thousands. In other words, bacterial biofilms appear to be designed to withstand extreme forces rather than typical or average loads. In scenarios requiring the removal or control of unwanted biofilms, this emphasizes the importance of considering strategies for structurally weakening the biofilms in conjunction with bacterial inactivation.}, } @article {pmid26819389, year = {2016}, author = {Rusten, B and Razafimanantsoa, VA and Andriamiarinjaka, MA and Otis, CL and Sahu, AK and Bilstad, T}, title = {Impact of fine mesh sieve primary treatment on nitrogen removal in moving bed biofilm reactors.}, journal = {Water science and technology : a journal of the International Association on Water Pollution Research}, volume = {73}, number = {2}, pages = {337-344}, doi = {10.2166/wst.2015.498}, pmid = {26819389}, issn = {0273-1223}, mesh = {Biofilms ; *Bioreactors ; Denitrification ; *Filtration ; Nitrification ; Nitrogen/*isolation & purification ; Sewage ; Wastewater ; Water Purification/*methods ; }, abstract = {The purpose of this project was to investigate the effect of selective particle removal during primary treatment on nitrogen removal in moving bed biofilm reactors (MBBRs). Two small MBBR pilot plants were operated in parallel, where one train treated 2 mm screened municipal wastewater and the other train treated wastewater that had passed through a Salsnes Filter SF1000 rotating belt sieve (RBS) with a 33 µs sieve cloth. The SF1000 was operated without a filter mat on the belt. The tests confirmed that, for the wastewater characteristics at the test plant, Salsnes Filter primary treatment with a 33 µs RBS and no filter mat produced a primary effluent that was close to optimum. Removal of organic matter with the 33 µs sieve had no negative effect on the denitrification process. Nitrification rates improved by 10-15% in the train with 33 µs RBS primary treatment. Mass balance calculations showed that without RBS primary treatment, the oxygen demand in the biological system was 36% higher. Other studies have shown that the sludge produced by RBS primary treatment is beneficial for biogas production and will also significantly improve sludge dewatering of the combined primary and biological sludge.}, } @article {pmid26819068, year = {2016}, author = {Ogura, M}, title = {Post-transcriptionally generated cell heterogeneity regulates biofilm formation in Bacillus subtilis.}, journal = {Genes to cells : devoted to molecular & cellular mechanisms}, volume = {21}, number = {4}, pages = {335-349}, doi = {10.1111/gtc.12343}, pmid = {26819068}, issn = {1365-2443}, mesh = {Bacillus subtilis/cytology/*physiology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Green Fluorescent Proteins/genetics ; Luminescent Proteins/metabolism ; Mutation ; RNA Processing, Post-Transcriptional ; Ribonucleases/metabolism ; }, abstract = {Bacillus subtilis forms biofilms in appropriate environments by producing extracellular matrices. Genes required for matrix formation, for example tapA, are regulated by the SinI/SinR/SlrR system. SinR is the repressor for tapA. SinI and SlrR inhibit DNA-binding of SinR. sinI and sinR constitute two-gene operon, and sinR has its own promoter. During biofilm formation, a portion of the population differentiates into matrix-producing cells. This is thought to be caused by Spo0A-dependent, heterogeneous expression of the PsinI promoter, whereas the PsinR promoter is expressed homogeneously. However, we observed that at its original locus, overall sinI transcription was almost homogeneous, because upstream read-through transcription from PyqHG would overcome expression of PsinI. When we used translational sinI-gfp and sinR-mCherry reporters at their original loci, their fluorescence distribution patterns in the cell population were clearly bimodal. This bimodal expression might be caused by cell-to-cell variations of mRNA stability. This study shows that the post-transcriptionally regulated bimodal expression of SinI and SinR is important for bacterial cell-fate determination.}, } @article {pmid26817804, year = {2016}, author = {Qu, L and She, P and Wang, Y and Liu, F and Zhang, D and Chen, L and Luo, Z and Xu, H and Qi, Y and Wu, Y}, title = {Effects of norspermidine on Pseudomonas aeruginosa biofilm formation and eradication.}, journal = {MicrobiologyOpen}, volume = {5}, number = {3}, pages = {402-412}, pmid = {26817804}, issn = {2045-8827}, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/drug effects/*growth & development ; Catheter-Related Infections/prevention & control ; Catheters/microbiology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Quorum Sensing/*drug effects/genetics ; Spermidine/*analogs & derivatives/pharmacology ; Virulence Factors/genetics ; }, abstract = {Biofilms are defined as aggregation of single cell microorganisms and associated with over 80% of all the microbial infections. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen capable of leading to various infections in immunocompromised people. Recent studies showed that norspermidine, a kind of polyamine, prevented and disrupted biofilm formation by some Gram-negative bacterium. In this study, the effects of norspermidine on P. aeruginosa biofilm formation and eradication were tested. Microtiter plate combined with crystal violet staining was used to study the effects of norspermidine on P. aeruginosa initial attachment, then we employed SEM (scanning electron microscope), qRT-PCR, and QS-related virulence factor assays to investigate how norspermidine prevent biofilm formation by P. aeruginosa. We reported that high-dose norspermidine had bactericide effect on P. aeruginosa, and norspermidine began to inhibit biofilm formation and eradicate 24-h mature biofilm at concentration of 0.1 and 1 mmol/L, respectively, probably by preventing cell-surface attachment, inhibiting swimming motility, and downregulating QS-related genes expression. To investigate the potential utility of norspermidine in preventing device-related infections, we found that catheters immersed with norspermidine were effective in eradicating mature biofilm. These results suggest that norspermidine could be a potent antibiofilm agent for formulating strategies against P. aeruginosa biofilm.}, } @article {pmid26814455, year = {2015}, author = {Neppelenbroek, KH}, title = {The importance of daily removal of the denture biofilm for oral and systemic diseases prevention.}, journal = {Journal of applied oral science : revista FOB}, volume = {23}, number = {6}, pages = {547-548}, pmid = {26814455}, issn = {1678-7765}, mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Denture Cleansers/*pharmacology ; Denture, Complete/*microbiology ; Female ; Humans ; Male ; Ricinus/*chemistry ; Sodium Hypochlorite/*pharmacology ; }, } @article {pmid26812821, year = {2015}, author = {Seixas, R and Varanda, D and Bexiga, R and Tavares, L and Oliveira, M}, title = {Biofilm-formation by Staphylococcus aureus and Staphylococcus epidermidis isolates from subclinical mastitis in conditions mimicking the udder environment.}, journal = {Polish journal of veterinary sciences}, volume = {18}, number = {4}, pages = {787-792}, doi = {10.1515/pjvs-2015-0102}, pmid = {26812821}, issn = {1505-1773}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*growth & development ; Cattle ; Female ; Mastitis, Bovine/*microbiology ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology/veterinary ; Staphylococcus aureus/drug effects/isolation & purification/*physiology ; Staphylococcus epidermidis/drug effects/isolation & purification/*physiology ; }, abstract = {Staphylococcus is the genus most commonly isolated from bovine mastitis in many countries. It may express several virulence factors including biofilm formation, which may protect the bacterial community from antimicrobials' action, preventing these compounds from reaching its interior, where they reach subinhibitory concentrations (subMIC). Most biofilm production assays are performed in static conditions, while studies regarding antimicrobial resistance usually do not resemble the udder environment because they are performed at high concentrations. In this study we evaluated the influence of dynamic conditions and media, including Mueller Hinton Broth (MHB) and UHT whole milk (WM), as well as the effect of subMIC concentrations of five different antimicrobial agents on biofilm formation by staphylococci isolated from subclinical mastitis. Results suggest that dynamic conditions and media may influence biofilm formation and revealed that milking simulation may significantly increase biofilm production. Sub-MIC concentrations decrease biofilm formation in MHB but increase in WM, suggesting a protective role of milk against antimicrobial compounds' action. Therefore, in vitro conditions that simulate the udder environment and in vivo conditions should be included as one of the parameters in evaluation of biofilm producing strains, in order to provide more reliable results.}, } @article {pmid26811321, year = {2016}, author = {Binepal, G and Gill, K and Crowley, P and Cordova, M and Brady, LJ and Senadheera, DB and Cvitkovitch, DG}, title = {Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance.}, journal = {Journal of bacteriology}, volume = {198}, number = {7}, pages = {1087-1100}, pmid = {26811321}, issn = {1098-5530}, support = {//Canadian Institutes of Health Research/Canada ; }, mesh = {Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Biological Transport ; Cation Transport Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial/physiology ; Homeostasis/*physiology ; Membrane Proteins/genetics/metabolism ; Osmoregulation/physiology ; Potassium/*metabolism ; Streptococcus mutans/genetics/*metabolism ; Stress, Physiological ; }, abstract = {UNLABELLED: Potassium (K(+)) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K(+) and a variety of K(+) transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K(+) acquisition in Streptococcus mutans and the importance of K(+) homeostasis for its virulence attributes. The S. mutans genome harbors four putative K(+) transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K(+) cotransporter (GlnQHMP), and a channel-like K(+) transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K(+)] less than 5 mM eliminated biofilm formation in S. mutans. The functionality of the Trk2 system was confirmed by complementing an Escherichia coli TK2420 mutant strain, which resulted in significant K(+) accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K(+)-dependent cellular response of S. mutans to environment stresses.

IMPORTANCE: Biofilm formation and stress tolerance are important virulence properties of caries-causing Streptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment of S. mutans. K(+) is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K(+) transporters in S. mutans. We identified the most important system for K(+) homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K(+) for the activity of biofilm-forming enzymes, which explains why such high levels of K(+) would favor biofilm formation.}, } @article {pmid26811181, year = {2016}, author = {Sharma, G and Sharma, S and Sharma, P and Chandola, D and Dang, S and Gupta, S and Gabrani, R}, title = {Escherichia coli biofilm: development and therapeutic strategies.}, journal = {Journal of applied microbiology}, volume = {121}, number = {2}, pages = {309-319}, doi = {10.1111/jam.13078}, pmid = {26811181}, issn = {1365-2672}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Drug Resistance, Microbial ; Escherichia coli/*drug effects/physiology ; Humans ; Plankton ; Prosthesis-Related Infections/drug therapy/microbiology ; Quorum Sensing/drug effects ; Urinary Tract Infections/drug therapy/microbiology ; }, abstract = {Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device-related infectivity. The cell-to-cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti-adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm-related infections.}, } @article {pmid26810653, year = {2016}, author = {Ahmadi, MS and Lee, HH and Sanchez, DA and Friedman, AJ and Tar, MT and Davies, KP and Nosanchuk, JD and Martinez, LR}, title = {Sustained Nitric Oxide-Releasing Nanoparticles Induce Cell Death in Candida albicans Yeast and Hyphal Cells, Preventing Biofilm Formation In Vitro and in a Rodent Central Venous Catheter Model.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {4}, pages = {2185-2194}, pmid = {26810653}, issn = {1098-6596}, support = {R56 DK087872/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Antifungal Agents/chemistry/*pharmacology ; Apoptosis/drug effects ; Biofilms/*drug effects/growth & development ; Candida albicans/*drug effects/growth & development ; Candidiasis/*drug therapy/microbiology ; Catheter-Related Infections/*drug therapy/microbiology ; Catheterization, Central Venous ; Chitosan/chemistry ; Disease Models, Animal ; Drug Therapy, Combination ; Female ; Fluconazole/pharmacology ; Fungal Polysaccharides/antagonists & inhibitors/chemistry ; Hyphae/drug effects ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Nanoparticles/chemistry ; Nitric Oxide/chemical synthesis/*pharmacology ; Nitric Oxide Donors/chemistry/pharmacology ; Organosilicon Compounds/chemistry ; Oxidation-Reduction ; Rats ; Rats, Sprague-Dawley ; Sodium Nitrite/chemistry ; Voriconazole/pharmacology ; }, abstract = {Candida albicansis a leading nosocomial pathogen. Today, candidal biofilms are a significant cause of catheter infections, and such infections are becoming increasingly responsible for the failure of medical-implanted devices.C. albicansforms biofilms in which fungal cells are encased in an autoproduced extracellular polysaccharide matrix. Consequently, the enclosed fungi are protected from antimicrobial agents and host cells, providing a unique niche conducive to robust microbial growth and a harbor for recurring infections. Here we demonstrate that a recently developed platform comprised of nanoparticles that release therapeutic levels of nitric oxide (NO-np) inhibits candidal biofilm formation, destroys the extracellular polysaccharide matrices of mature fungal biofilms, and hinders biofilm development on surface biomaterials such as the lumen of catheters. We found NO-np to decrease both the metabolic activity of biofilms and the cell viability ofC. albicansin vitroandin vivo Furthermore, flow cytometric analysis found NO-np to induce apoptosis in biofilm yeast cellsin vitro Moreover, NO-np behave synergistically when used in combination with established antifungal drug therapies. Here we propose NO-np as a novel treatment modality, especially in combination with standard antifungals, for the prevention and/or remediation of fungal biofilms on central venous catheters and other medical devices.}, } @article {pmid26809836, year = {2016}, author = {Kłodowska, I and Rodziewicz, J and Janczukowicz, W and Gotkowska-Płachta, A and Cydzik-Kwiatkowska, A}, title = {Hydrogenotrophic denitrification process efficiency and the number of denitrifying bacteria (MPN) in the sequencing batch biofilm reactor (SBBR) with platinum and carbon anodes.}, journal = {Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering}, volume = {51}, number = {5}, pages = {389-392}, doi = {10.1080/10934529.2015.1120516}, pmid = {26809836}, issn = {1532-4117}, mesh = {Bacteria, Anaerobic/*metabolism ; Biofilms/drug effects ; Bioreactors/microbiology ; Carbon/*chemistry ; *Denitrification ; Electric Conductivity ; Environmental Restoration and Remediation/methods ; Nitrogen/*metabolism ; Oxidation-Reduction ; Platinum/*chemistry ; Wastewater/*chemistry/*microbiology ; }, abstract = {This work reports on the effect of electric current density and anode material (platinum, carbon) on the concentration of oxidized and mineral forms of nitrogen, on physical parameters (pH, redox potential, electrical conductivity) and the number of denitrifying bacteria in the biofilm (MPN). Experiments were conducted under anaerobic conditions without and with the flow of electric current (with density of 79 mA · m(-2) and 132 mA · m(-2)). Results obtained in the study enabled concluding that increasing density of electric current caused a decreasing concentration of nitrate in the reactor with platinum anode (R1) and carbon anode (R2). Its concentration depended on anode material. The highest hydrogenotrophic denitrification efficiency was achieved in R2 in which the process was aided by inorganic carbon (CO2) that originated from carbon anode oxidation and the electrical conductivity of wastewater increased as a result of the presence of HCO3(-) and CO3(2-) ions. Strong oxidizing properties of the platinum anode (R1) prevented the accumulation of adverse forms of nitrogen, including nitrite and ammonia. The increase in electric current density affected also a lower number of denitrifying bacteria (MPN) in the biofilm in both reactors (R1 and R2). Metal oxides accumulated on the surface of the cathode had a toxic effect upon microorganisms and impaired the production of a hydrogen donor.}, } @article {pmid26809044, year = {2016}, author = {Brody, GS}, title = {The Case against Biofilm as the Primary Initiator of Breast Implant-Associated Anaplastic Large Cell Lymphoma.}, journal = {Plastic and reconstructive surgery}, volume = {137}, number = {4}, pages = {766e-767e}, doi = {10.1097/01.prs.0000480003.80422.03}, pmid = {26809044}, issn = {1529-4242}, mesh = {*Biofilms ; Breast Implants/adverse effects/*microbiology ; Breast Neoplasms/*etiology ; Female ; Humans ; Lymphoma, Large-Cell, Anaplastic/*etiology ; Risk Factors ; }, } @article {pmid26808465, year = {2016}, author = {Ouyang, J and Sun, F and Feng, W and Sun, Y and Qiu, X and Xiong, L and Liu, Y and Chen, Y}, title = {Quercetin is an effective inhibitor of quorum sensing, biofilm formation and virulence factors in Pseudomonas aeruginosa.}, journal = {Journal of applied microbiology}, volume = {120}, number = {4}, pages = {966-974}, doi = {10.1111/jam.13073}, pmid = {26808465}, issn = {1365-2672}, mesh = {Biofilms/drug effects/growth & development ; Pseudomonas aeruginosa/*drug effects/physiology ; Quercetin/*pharmacology ; Quorum Sensing/*drug effects ; Virulence Factors/analysis/*biosynthesis ; }, abstract = {AIMS: The study aimed to perform a systematic investigation of the effects of quercetin on biofilm formation and virulence factors in Pseudomonas aeruginosa.

METHODS AND RESULTS: The Ps. aeruginosa strain PAO1 was selected as the test strain. The results indicated that quercetin did not impact the growth of PAO1 as determined by MIC and growth curve analysis. However, this compound significantly inhibited (P < 0·05) biofilm formation and production of virulence factors including pyocyanin, protease and elastase at a lower concentration than those for most previously reported plant extracts and substances. Considering the central role of quorum sensing (QS) in the regulation of biofilm and virulence factor, we further detected the transcriptional changes associated with QS and found that the expression levels of lasI, lasR, rhlI and rhlR were significantly reduced (P < 0·05) by 34, 68, 57 and 50%, respectively, in response to 16 μg ml(-1) quercetin.

CONCLUSIONS: This study indicated that quercetin is an effective inhibitor of biofilm formation and virulence factors in Ps. aeruginosa.

This is the first study to demonstrate that quercetin is an effective inhibitor of QS, biofilm formation and virulence factors in Ps. aeruginosa. Furthermore, quercetin might have potential in fighting biofilm-related infections.}, } @article {pmid26807439, year = {2016}, author = {Raman, N and Marchillo, K and Lee, MR and Rodríguez López, AL and Andes, DR and Palecek, SP and Lynn, DM}, title = {Intraluminal Release of an Antifungal β-Peptide Enhances the Antifungal and Anti-Biofilm Activities of Multilayer-Coated Catheters in a Rat Model of Venous Catheter Infection.}, journal = {ACS biomaterials science & engineering}, volume = {2}, number = {1}, pages = {112-121}, pmid = {26807439}, issn = {2373-9878}, support = {R01 AI073289/AI/NIAID NIH HHS/United States ; R01 AI092225/AI/NIAID NIH HHS/United States ; }, abstract = {Candida albicans is the most prevalent cause of hospital-acquired fungal infections and forms biofilms on indwelling medical devices that are notoriously difficult to treat or remove. We recently demonstrated that the colonization of C. albicans on the surfaces of catheter tube segments can be reduced in vitro by coating them with polyelectrolyte multilayers (PEMs) that release a potent antifungal β-peptide. Here, we report on the impact of polymer structure and film composition on both the inherent and β-peptide-mediated ability of PEM-coated catheters to prevent or reduce the formation of C. albicans biofilms in vitro and in vivo using a rat model of central venous catheter infection. Coatings fabricated using polysaccharide-based components [hyaluronic acid (HA) and chitosan (CH)] and coatings fabricated using polypeptide-based components [poly-l-lysine (PLL) and poly-l-glutamic acid (PGA)] both served as reservoirs for the loading and sustained release of β-peptide, but differed substantially in loading and release profiles and in their inherent antifungal properties (e.g., the ability to prevent colonization and biofilm growth in the absence of β-peptide). In particular, CH/HA films exhibited inherent antifungal and antibiofilm behaviors in vitro and in vivo, a result we attribute to the incorporation of CH, a weak polycation demonstrated to exhibit antimicrobial properties in other contexts. The antifungal properties of both types of films were improved substantially when β-peptide was incorporated. Catheter segments coated with β-peptide-loaded CH/HA and PLL/PGA films were both strongly antifungal against planktonic C. albicans and the formation of surface-associated biofilms in vitro and in vivo. Our results demonstrate that PEM coatings provide a useful platform for the design of new antifungal materials, and suggest opportunities to design multifunctional or dual-action platforms to prevent or reduce the severity of fungal infections in applied biomedical contexts or other areas in which fungal biofilms are endemic.}, } @article {pmid26806408, year = {2016}, author = {Shen, Y and Wang, Z and Wang, J and Zhou, Y and Chen, H and Wu, C and Haapasalo, M}, title = {Bifunctional bioceramics stimulating osteogenic differentiation of a gingival fibroblast and inhibiting plaque biofilm formation.}, journal = {Biomaterials science}, volume = {4}, number = {4}, pages = {639-651}, doi = {10.1039/c5bm00534e}, pmid = {26806408}, issn = {2047-4849}, mesh = {Alkaline Phosphatase/chemistry/metabolism ; Biocompatible Materials/*chemistry/pharmacology ; Biofilms/*drug effects ; Cell Differentiation/*drug effects/physiology ; Cementogenesis/drug effects/physiology ; Dental Plaque/*chemistry/*microbiology ; Fibroblasts/*chemistry/microbiology ; Gingiva/chemistry/*metabolism ; Humans ; Ions/*chemistry/*pharmacology ; Osteogenesis/*drug effects/physiology ; }, abstract = {Gingival recession is a common clinical problem that results in esthetic deficiencies and poor plaque control and predominantly occurs in aged patients. In order to restore the cervical region, ideal biomaterials should possess the ability to stimulate proliferation and osteogenesis/cementogenesis of human gingival fibroblasts (HGF) and have a strong antibiofilm effect. The aim of the present study was to investigate the interactions of HGF and oral multispecies biofilms with Ca, Mg and Si-containing bredigite (BRT, Ca7MgSi4O16) bioceramics. BRT extract induced osteogenic/cementogenic differentiation of HGF and its inhibition of plaque biofilm formation were systematically studied. BRT extract in concentrations lower than <200 mg mL(-1) presented high biocompatibility to HGF cells in 3 days. Ion extracts from BRT also stimulated a series of bone-related gene and protein expressions in HGF cells. Furthermore, BRT extract significantly inhibited oral multispecies plaque biofilm growth on its surface and contributed to over 30% bacterial cell death without additional antibacterial agents in two weeks. A planktonic killing test showed that BRT suppressed 98% plaque bacterial growth compared to blank control in 3 days. The results also revealed that BRT extract has an osteostimulation effect on HGF. The suppression effect on plaque biofilms suggested that BRT might be used as a bioactive material for cervical restoration and that the synergistic effect of bioactive ions, such as Ca, Mg and Si ions, played an important role in the design and construction of bifunctional biomaterials in combination with tissue regeneration and antibiofilm activity.}, } @article {pmid26804665, year = {2016}, author = {Ontiveros-Valencia, A and Penton, CR and Krajmalnik-Brown, R and Rittmann, BE}, title = {Hydrogen-fed biofilm reactors reducing selenate and sulfate: Community structure and capture of elemental selenium within the biofilm.}, journal = {Biotechnology and bioengineering}, volume = {113}, number = {8}, pages = {1736-1744}, doi = {10.1002/bit.25945}, pmid = {26804665}, issn = {1097-0290}, mesh = {Bacteria/genetics ; *Biofilms ; Bioreactors/*microbiology ; Hydrogen/*metabolism ; Selenic Acid/analysis/chemistry/*metabolism ; Selenium/analysis/isolation & purification/*metabolism ; Sulfates/analysis/chemistry/*metabolism ; }, abstract = {Remediation of selenate (SeO4 (2-)) contamination through microbial reduction is often challenging due to the presence of sulfate (SO4 (2-)), which can lead to competition for the electron donor and the co-production of toxic H2 S. Microbial reduction of SeO4 (2-) in the presence of SO4 (2-) was studied in two hydrogen-based membrane biofilm reactors (MBfRs). One MBfR was initiated with SO4 (2-) -reducing conditions and gradually shifted to SeO4 (2-) reduction. The second MBfR was developed with a SeO4 (2-) -reducing biofilm, followed by SO4 (2-) introduction. Biofilms within both MBfRs achieved greater than 90% SeO4 (2-) reduction, even though the SeO4 (2-) concentration ranged from 1,000-11,000 μg/L, more than 20-200 times the maximum contaminant level for drinking water (50 μg/L). Biofilm microbial community composition, assessed by 16S rRNA gene-based amplicon pyrosequencing, was distinct between the two MBfRs and was framed by alterations in SeO4 (2-) loading. Specifically, high SeO4 (2-) loading resulted in communities mainly composed of denitrifying bacteria (e.g., Denitratisoma and Dechloromonas). In contrast, low loading led to mostly sulfate-reducing bacteria (i.e., Desulfovibrio) and sulfur-oxidizing bacteria (i.e., Sulfuricurvum and Sulfurovum). SeO4 (2-) was reduced to elemental selenium (Se°), which was visualized within the biofilm as crystalloid aggregates, with its fate corresponding to that of biofilm solids. In conclusion, microbial biofilm communities initiated under either SeO4 (2-) or SO4 (2-) -reducing conditions attained high SeO4 (2-) removal rates even though their microbial community composition was quite distinct. Biotechnol. Bioeng. 2016;113: 1736-1744. © 2016 Wiley Periodicals, Inc.}, } @article {pmid26804206, year = {2016}, author = {Francesko, A and Fernandes, MM and Ivanova, K and Amorim, S and Reis, RL and Pashkuleva, I and Mendoza, E and Pfeifer, A and Heinze, T and Tzanov, T}, title = {Bacteria-responsive multilayer coatings comprising polycationic nanospheres for bacteria biofilm prevention on urinary catheters.}, journal = {Acta biomaterialia}, volume = {33}, number = {}, pages = {203-212}, doi = {10.1016/j.actbio.2016.01.020}, pmid = {26804206}, issn = {1878-7568}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Coated Materials, Biocompatible/*pharmacology ; Microbial Sensitivity Tests ; Microscopy, Atomic Force ; Microscopy, Fluorescence ; Nanospheres/*chemistry ; Polyamines/*pharmacology ; Polyelectrolytes ; Pseudomonas aeruginosa/*drug effects ; Silicones/pharmacology ; Spectroscopy, Fourier Transform Infrared ; Urinary Catheters/*microbiology ; }, abstract = {UNLABELLED: This work reports on the development of infection-preventive coatings on silicone urinary catheters that contain in their structure and release on demand antibacterial polycationic nanospheres. Polycationic aminocellulose conjugate was first sonochemically processed into nanospheres to improve its antibacterial potential compared to the bulk conjugate in solution (ACSol). Afterward the processed aminocellulose nanospheres (ACNSs) were combined with the hyaluronic acid (HA) polyanion to build a layer-by-layer construct on silicone surfaces. Although the coating deposition was more effective when HA was coupled with ACSol than with ACNSs, the ACNSs-based coatings were thicker and displayed smoother surfaces due to the embedment of intact nanospheres. The antibacterial effect of ACNSs multilayers was 40% higher compared to ACSol coatings. This fact was further translated into more effective prevention of Pseudomonas aeruginosa biofilm formation. The coatings were stable in the absence of bacteria, whereas their disassembling occurred gradually during incubation with P. aeruginosa, and thus eradicate the biofilm upon release of antibacterial agents. Only 5 bilayers of HA/ACNSs were sufficient to prevent the biofilm formation, in contrast to the 10 bilayers of ACSol required to achieve the same effect. The antibiofilm efficiency of (HA/ACNSs)10 multilayer construct built on a Foley catheter was additionally validated under dynamic conditions using a model of the catheterized bladder in which the biofilm was grown during seven days.

STATEMENT OF SIGNIFICANCE: Antibacterial layer-by-layer coatings were fabricated on silicone that efficiently prevents Pseudomonas aeruginosa biofilm formation during time beyond the useful lifetime of the currently employed urinary catheters in medical practice. The coatings are composed of intact, highly antibacterial polycationic nanospheres processed from aminated cellulose and bacteria-degrading glycosaminoglycan hyaluronic acid. The importance of incorporating nanoscale structures within bacteria-responsive surface coatings to impart durable antibacterial and self-defensive properties to the medical indwelling devices is highlighted.}, } @article {pmid26802475, year = {2016}, author = {Young, B and Banihashemi, B and Forrest, D and Kennedy, K and Stintzi, A and Delatolla, R}, title = {Meso and micro-scale response of post carbon removal nitrifying MBBR biofilm across carrier type and loading.}, journal = {Water research}, volume = {91}, number = {}, pages = {235-243}, doi = {10.1016/j.watres.2016.01.006}, pmid = {26802475}, issn = {1879-2448}, mesh = {Ammonia/*metabolism ; *Bacterial Physiological Phenomena ; *Biofilms ; Bioreactors/*microbiology ; Carbon/*metabolism ; *Nitrification ; Waste Disposal, Fluid/instrumentation/*methods ; }, abstract = {This study investigates the effects of three specific moving bed biofilm reactor (MBBR) carrier types and two surface area loading rates on biofilm thickness, morphology and bacterial community structure of post carbon removal nitrifying MBBR systems along with the effects of carrier type and loading on ammonia removal rates and effluent solids settleability. The meso and micro analyses show that the AOB kinetics vary based on loading condition, but irrespective of carrier type. The meso-scale response to increases in loading was shown to be an increase in biofilm thickness with higher surface area carriers being more inclined to develop and maintain thicker biofilms. The pore spaces of these higher surface area to volume carriers also demonstrated the potential to become clogged at higher loading conditions. Although the biofilm thickness increased during higher loading conditions, the relative percentages of both the embedded viable and non-viable cells at high and conventional loading conditions remained stable; indicating that the reduced ammonia removal kinetics observed during carrier clogging events is likely due to the observed reduction in the surface area of the attached biofilm. Microbial community analyses demonstrated that the dominant ammonia oxidizing bacteria for all carriers is Nitrosomonas while the dominant nitrite oxidizing bacteria is Nitrospira. The research showed that filamentous species were abundant under high loading conditions, which likely resulted in the observed reduction in effluent solids settleability at high loading conditions as opposed to conventional loading conditions. Although the settleability of the effluent solids was correlated to increases in abundances of filamentous organisms in the biofilm, analyzed using next generation sequencing, the ammonia removal rate was not shown to be directly correlated to specific meso or micro-scale characteristics. Instead post carbon removal MBBR ammonia removal kinetics were shown to be related to the viable AOB cell coverage of the carriers; which was calculated by normalizing the surface area removal rate by the biofilm thickness, the bacterial percent abundance of ammonia oxidizing bacteria and the percentage of viable cells.}, } @article {pmid26800864, year = {2016}, author = {Randrianjatovo-Gbalou, I and Girbal-Neuhauser, E and Marcato-Romain, CE}, title = {Quantification of biofilm exopolysaccharides using an in situ assay with periodic acid-Schiff reagent.}, journal = {Analytical biochemistry}, volume = {500}, number = {}, pages = {12-14}, doi = {10.1016/j.ab.2016.01.008}, pmid = {26800864}, issn = {1096-0309}, mesh = {*Biofilms ; Periodic Acid/*chemistry ; Polysaccharides/*analysis ; Rosaniline Dyes/chemistry ; }, abstract = {A novel approach to the quantification of extracellular polysaccharides in miniaturized biofilms presenting a wide variety of extracellular matrices was developed. The assay used the periodic acid-Schiff reagent and was first calibrated on dextran and alginate solutions. Then it was implemented on 24-h and 48-h biofilms from three strains known to produce different exopolymeric substances (Pseudomonas aeruginosa, Bacillus licheniformis, Weissella confusa). The assay allowed quantification of the total exopolysaccharides, taking into account possible interferences due to cells or other main expolymers of the matrix (eDNA, proteins).}, } @article {pmid26800339, year = {2016}, author = {Hosohama-Saito, K and Kokubu, E and Okamoto-Shibayama, K and Kita, D and Katakura, A and Ishihara, K}, title = {Involvement of luxS in Biofilm Formation by Capnocytophaga ochracea.}, journal = {PloS one}, volume = {11}, number = {1}, pages = {e0147114}, pmid = {26800339}, issn = {1932-6203}, mesh = {Bacterial Proteins/genetics/*physiology ; *Biofilms ; Capnocytophaga/genetics/*physiology ; Carbon-Sulfur Lyases/genetics/*physiology ; Homologous Recombination ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Mutation ; }, abstract = {Capnocytophaga ochracea is present in the dental plaque biofilm of patients with periodontitis. Biofilm cells change their phenotype through quorum sensing in response to fluctuations in cell-population density. Quorum sensing is mediated by auto-inducers (AIs). AI-2 is involved in intercellular signaling, and production of its distant precursor is catalyzed by LuxS, an enzyme involved in the activated methyl cycle. Our aim was to clarify the role of LuxS in biofilm formation by C. ochracea. Two luxS-deficient mutants, TmAI2 and LKT7, were constructed from C. ochracea ATCC 27872 by homologous recombination. The mutants produced significantly less AI-2 than the wild type. The growth rates of these mutants were similar to that of the wild-type in both undiluted Tryptic soy broth and 0.5 × Tryptic soy broth. However, according to crystal violet staining, they produced significantly less biofilm than the wild type. Confocal laser scanning microscopy and scanning electron microscopy showed that the biofilm of the TmAI2 strain had a rougher structure than that of the wild type. Complementation of TmAI-2 with extrinsic AI-2 from the culture supernatant of wild-type strain did not restore biofilm formation by the TmAI2 strain, but complementation of LKT7 strain with luxS partially restored biofilm formation. These results indicate that LuxS is involved in biofilm formation by C. ochracea, and that the attenuation of biofilm formation by the mutants is likely caused by a defect in the activated methyl cycle rather than by a loss of AI-2.}, } @article {pmid26799073, year = {2016}, author = {Khodaparast, L and Khodaparast, L and Shahrooei, M and Stijlemans, B and Merckx, R and Baatsen, P and O'Gara, JP and Waters, E and Van Mellaert, L and Van Eldere, J}, title = {The Possible Role of Staphylococcus epidermidis LPxTG Surface Protein SesC in Biofilm Formation.}, journal = {PloS one}, volume = {11}, number = {1}, pages = {e0146704}, pmid = {26799073}, issn = {1932-6203}, mesh = {Adhesins, Bacterial/metabolism ; Animals ; Bacterial Proteins/genetics ; Biofilms/*growth & development ; Catheter-Related Infections/*microbiology ; Central Venous Catheters/microbiology ; Gene Expression Regulation, Bacterial ; Jugular Veins/surgery ; Membrane Proteins/*genetics/immunology/metabolism ; Mice ; Microscopy, Electron, Scanning ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/genetics/*pathogenicity ; Staphylococcus epidermidis/genetics/*pathogenicity ; }, abstract = {Staphylococcus epidermidis is the most common cause of device-associated infections. It has been shown that active and passive immunization in an animal model against protein SesC significantly reduces S. epidermidis biofilm-associated infections. In order to elucidate its role, knock-out of sesC or isolation of S. epidermidis sesC-negative mutants were attempted, however, without success. As an alternative strategy, sesC was introduced into Staphylococcus aureus 8325-4 and its isogenic icaADBC and srtA mutants, into the clinical methicillin-sensitive S. aureus isolate MSSA4 and the MRSA S. aureus isolate BH1CC, which all lack sesC. Transformation of these strains with sesC i) changed the biofilm phenotype of strains 8325-4 and MSSA4 from PIA-dependent to proteinaceous even though PIA synthesis was not affected, ii) converted the non-biofilm-forming strain 8325-4 ica::tet to a proteinaceous biofilm-forming strain, iii) impaired PIA-dependent biofilm formation by 8325-4 srtA::tet, iv) had no impact on protein-mediated biofilm formation of BH1CC and v) increased in vivo catheter and organ colonization by strain 8325-4. Furthermore, treatment with anti-SesC antibodies significantly reduced in vitro biofilm formation and in vivo colonization by these transformants expressing sesC. These findings strongly suggest that SesC is involved in S. epidermidis attachment to and subsequent biofilm formation on a substrate.}, } @article {pmid26797908, year = {2016}, author = {Castaneda, P and McLaren, A and Tavaziva, G and Overstreet, D}, title = {Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time.}, journal = {Clinical orthopaedics and related research}, volume = {474}, number = {7}, pages = {1659-1664}, pmid = {26797908}, issn = {1528-1132}, support = {R41 AR065917/AR/NIAMS NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Dose-Response Relationship, Drug ; Escherichia coli/*drug effects/growth & development ; Methicillin-Resistant Staphylococcus aureus/drug effects/growth & development ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; Pseudomonas aeruginosa/*drug effects/growth & development ; Staphylococcus/*drug effects/growth & development ; Staphylococcus epidermidis/drug effects/growth & development ; Time Factors ; Tobramycin/*pharmacology ; Vancomycin/*pharmacology ; }, abstract = {BACKGROUND: The antimicrobial concentration required to kill all the bacteria in a biofilm, known as the minimum biofilm eradication concentration (MBEC), is typically determined in vitro by exposing the biofilm to serial concentrations of antimicrobials for 24 hours or less. Local delivery is expected to cause high local levels for longer than 24 hours. It is unknown if longer antimicrobial exposures require the same concentration to eradicate bacteria in biofilm. Questions/purposes Does MBEC change with increased antimicrobial exposure time?

METHODS: Biofilms were grown for 24 hours using five pathogens (methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa) and then exposed to four antimicrobials regimens: tobramycin, vancomycin, and tobramycin combined with vancomycin in 3:1 and 1:1 ratios by weight in concentrations of 62.5, 125, 250, 500, 1000, 2000, 4000, and 8000 μg/mL for three durations, 1, 3, and 5 days, in triplicate. MBEC was measured as the lowest concentration that killed all bacteria in the biofilm determined by 21-day subculture.

RESULTS: MBEC was lower when antimicrobial exposure time was longer. For the staphylococcus species, the MBEC was lower when exposure time was 5 days than 1 day in 11 of 12 antimicrobial/microorganism pairs. The MBEC range for these 11 pairs on Day 1 was 4000 to > 8000 μg/mL and on Day 5 was < 250 to 8000 μg/mL. MBEC for tobramycin/P. aeruginosa was 2000 μg/mL on Day 1 and ≤ 250 μg/mL on Day 5, and for E. coli, 125 μg/mL on Day 1 and ≤ 62.5 on Day 5.

CONCLUSIONS: Although antimicrobial susceptibility was lower for longer exposure times in the microorganisms we studied, confirmation is required for other pathogens. Clinical Relevance One-day MBEC assays may overestimate the local antimicrobial levels needed to kill organisms in biofilm if local levels are sustained at MBEC or above for longer than 24 hours. Future studies are needed to confirm that antimicrobial levels achieved clinically from local delivery are above the MBEC at relevant time points and to confirm that MBEC for in vitro microorganisms accurately represents MBEC of in vivo organisms in an clinical infection.}, } @article {pmid26796707, year = {2016}, author = {Cohen-Berneron, J and Steinberg, D and Featherstone, JD and Feuerstein, O}, title = {Sustained effects of blue light on Streptococcus mutans in regrown biofilm.}, journal = {Lasers in medical science}, volume = {31}, number = {3}, pages = {445-452}, pmid = {26796707}, issn = {1435-604X}, mesh = {Biofilms/growth & development/*radiation effects ; Dental Caries/microbiology ; Humans ; Hydrogen-Ion Concentration ; Light ; Microbial Viability/radiation effects ; Microscopy, Confocal ; Streptococcus mutans/growth & development/*radiation effects ; }, abstract = {In prior studies, exposure of Streptococcus mutans in biofilm to blue light using high fluences of up to 680 J/cm(2) did not interfere with bacterial capability to reform an initial biofilm; however, a delayed antibacterial effect was observed. Our aim was to determine the sustained effecttts of blue light-emitting diode (LED) curing light on the pathogenicity of the newly formed biofilm. S. mutans were grown to form biofilm that was exposed to blue light (wavelengths, 460-480 nm) for 1, 3, and 7 min (equivalent to 37, 112, and 262 J/cm(2), respectively). Then, bacteria were suspended and allowed to regrow into new biofilms. The regrown biofilms were assessed for bacterial quantification by optical density (OD) measurement and quantitative polymerase chain reaction (qPCR), bacterial viability and extracellular polysaccharide production by fluorescent staining using confocal scanning laser microscopy, acid production by bacteria (acidogenicity), and bacterial survival at low pH (aciduricity) using qPCR. Bacterial growth in the regrown biofilms was increased when samples were previously exposed to light; however, under the confocal microscopy, a higher proportion of dead bacteria and a reduction in polysaccharide production were observed. The acidogenicity from the regrown biofilm was lowered as fluences of light increased. The aciduricity of the regrown biofilm was decreased, meaning less growth of bacteria into biofilm in low pH with increasing fluences. Blue light has sustained effects on S. mutans bacteria grown into new biofilm. Although bacterial growth in biofilm increased, bacterial viability and virulence characteristics were impaired. The cariogenic potential over time of S. mutans previously exposed to blue light when grown on tooth surfaces is yet to be determined.}, } @article {pmid26796329, year = {2016}, author = {Smith, KP and Ruiz, T and Mintz, KP}, title = {Inner-membrane protein MorC is involved in fimbriae production and biofilm formation in Aggregatibacter actinomycetemcomitans.}, journal = {Microbiology (Reading, England)}, volume = {162}, number = {3}, pages = {513-525}, pmid = {26796329}, issn = {1465-2080}, support = {S10 RR019246/RR/NCRR NIH HHS/United States ; R01-DE017474/DE/NIDCR NIH HHS/United States ; R01 DE017474/DE/NIDCR NIH HHS/United States ; R01-DE018889/DE/NIDCR NIH HHS/United States ; R01 DE018889/DE/NIDCR NIH HHS/United States ; 1S10RR019246/RR/NCRR NIH HHS/United States ; }, mesh = {Aggregatibacter actinomycetemcomitans/genetics/growth & development/metabolism/*physiology ; Biofilms/*growth & development ; Fimbriae Proteins/*metabolism ; Fimbriae, Bacterial/*metabolism ; Gene Deletion ; Genetic Complementation Test ; Membrane Proteins/genetics/*metabolism ; *Organelle Biogenesis ; }, abstract = {Fimbrial subunit synthesis, secretion and assembly on the surface of the periodontal pathogen Aggregatibacter actinomycetemcomitans are essential for biofilm formation. A recent quantitative proteomics study employing an afimbriated strain and a developed mutant isogenic for the inner-membrane protein morphogenesis protein C (MorC) revealed that the abundance of the proteins of the fimbrial secretion apparatus in the membrane is dependent on MorC. To investigate further the relationship between MorC and fimbriation, we identified and complemented the defect in fimbriae production in the afimbriated laboratory strain. The transformed strain expressing a plasmid containing genes encoding the WT fimbrial subunit and the prepilin peptidase displayed all of the hallmarks of a fimbriated bacterium including the distinct star-like colony morphology, robust biofilm formation, biofilm architecture composed of discrete microcolonies and the presence of fimbriae. When the identical plasmid was transformed into a morC mutant strain, the bacterium did not display any of the phenotypes of fimbriated strains. Extension of these studies to a naturally fimbriated clinical strain showed that the resulting morC mutant maintained the characteristic colony morphology of fimbriated strains. There was, however, a reduction in the secretion of fimbrial subunits, and fewer fimbriae were observed on the surface of the mutant strain. Furthermore, the morC mutant of the fimbriated strain displayed a significantly altered biofilm microcolony architecture, while maintaining a similar biofilm mass to the parent strain. These results suggest that MorC influences fimbrial secretion and microcolony formation in A. actinomycetemcomitans.}, } @article {pmid26796296, year = {2016}, author = {Xie, F and Li, G and Zhang, Y and Zhou, L and Liu, S and Liu, S and Wang, C}, title = {The Lon protease homologue LonA, not LonC, contributes to the stress tolerance and biofilm formation of Actinobacillus pleuropneumoniae.}, journal = {Microbial pathogenesis}, volume = {93}, number = {}, pages = {38-43}, doi = {10.1016/j.micpath.2016.01.009}, pmid = {26796296}, issn = {1096-1208}, mesh = {Actinobacillus Infections/*microbiology ; Actinobacillus pleuropneumoniae/*enzymology/*physiology ; Animals ; Bacterial Proteins/chemistry/genetics/*metabolism ; *Biofilms ; Female ; Humans ; Mice ; Mice, Inbred BALB C ; Protease La/chemistry/genetics/*metabolism ; Protein Domains ; Stress, Physiological ; }, abstract = {Lon proteases are a family of ATP-dependent proteases that are involved in the degradation of abnormal proteins in bacteria exposed to adverse environmental stress. An analysis of the genome sequence of Actinobacillus pleuropneumoniae revealed the unusual presence of two putative ATP-dependent Lon homologues, LonA and LonC. Sequence comparisons indicated that LonA has the classical domain organization of the LonA subfamily, which includes the N-terminal domain, central ATPase (AAA) domain, and C-terminal proteolytic (P) domain. LonC belongs to the recently classified LonC subfamily, which includes Lon proteases that contain neither the N-terminal domain of LonA nor the transmembrane region that is present only in LonB subfamily members. To investigate the roles of LonA and LonC in A. pleuropneumoniae, mutants with deletions in the lonA and lonC genes were constructed. The impaired growth of the △lonA mutant exposed to low and high temperatures and osmotic and oxidative stress conditions indicates that the LonA protease is required for the stress tolerance of A. pleuropneumoniae. Furthermore, the △lonA mutant exhibited significantly reduced biofilm formation compared to the wild-type strain. However, no significant differences in stress responses or biofilm formation were observed between the △lonC mutant and the wild-type strain. The △lonA mutant exhibited reduced colonization ability and attenuated virulence of A. pleuropneumoniae in the BALB/c mouse model compared to the wild-type strain. Disruption of lonC gene did not significantly influence the colonization and virulence of A. pleuropneumoniae. The data presented in this study illustrate that the LonA protease, but not the LonC protease, is required for the stress tolerance, biofilm formation and pathogenicity of A. pleuropneumoniae.}, } @article {pmid26795221, year = {2015}, author = {Legéňová, K and Bujdáková, H}, title = {[The role of Streptococcus mutans in the oral biofilm].}, journal = {Epidemiologie, mikrobiologie, imunologie : casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne}, volume = {64}, number = {4}, pages = {179-187}, pmid = {26795221}, issn = {1210-7913}, mesh = {Animals ; *Biofilms ; Dental Caries/*microbiology ; Glucans/metabolism ; Humans ; Streptococcus mutans/genetics/*physiology ; Virulence Factors/genetics/metabolism ; }, abstract = {Streptococcus mutans is one of the primary colonizers of the oral cavity. Carriage of the appropriate virulence factors - production of glucans, acid resistance, natural competence, and ability to form compact biofilm, confers a certain advantage to S. mutans over other primary colonizers. It is believed to be the main etiological agent of dental caries. Currently, dental caries seems to be a phenomenon related to the meta-bolic activity of bacteria in the oral biofilm with an impact not only on health but also on socio-economic outcome.}, } @article {pmid26793174, year = {2015}, author = {Anderson, AC and Jonas, D and Huber, I and Karygianni, L and Wölber, J and Hellwig, E and Arweiler, N and Vach, K and Wittmer, A and Al-Ahmad, A}, title = {Enterococcus faecalis from Food, Clinical Specimens, and Oral Sites: Prevalence of Virulence Factors in Association with Biofilm Formation.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1534}, pmid = {26793174}, issn = {1664-302X}, abstract = {Enterococci have gained significance as the cause of nosocomial infections; they occur as food contaminants and have also been linked to dental diseases. E. faecalis has a great potential to spread virulence as well as antibiotic resistance genes via horizontal gene transfer. The integration of food-borne enterococci into the oral biofilm in-vivo has been observed. Therefore, we investigated the virulence determinants and antibiotic resistance of 97 E. faecalis isolates from the oral cavity, food, and clinical specimens. In addition, phenotypic expression of gelatinase and cytolysin were tested, in-vitro biofilm formation was quantified and isolates were compared for strain relatedness via pulsed field gel electrophoresis (PFGE). Each isolate was found to possess two or more virulence genes, most frequently gelE, efaA, and asa1. Notably, plaque/saliva isolates possessed the highest abundance of virulence genes, the highest levels of phenotypic gelatinase and hemolysin activity and concurrently a high ability to form biofilm. The presence of asa1 was associated with biofilm formation. The biofilm formation capacity of clinical and plaque/saliva isolates was considerably higher than that of food isolates and they also showed similar antibiotic resistance patterns. These results indicate that the oral cavity can constitute a reservoir for virulent E. faecalis strains possessing antibiotic resistance traits and at the same time distinct biofilm formation capabilities facilitating exchange of genetic material.}, } @article {pmid26792674, year = {2016}, author = {Thakur, P and Chawla, R and Tanwar, A and Chakotiya, AS and Narula, A and Goel, R and Arora, R and Sharma, RK}, title = {Attenuation of adhesion, quorum sensing and biofilm mediated virulence of carbapenem resistant Escherichia coli by selected natural plant products.}, journal = {Microbial pathogenesis}, volume = {92}, number = {}, pages = {76-85}, doi = {10.1016/j.micpath.2016.01.001}, pmid = {26792674}, issn = {1096-1208}, mesh = {Alkaloids/chemistry ; Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Bacterial Adhesion/drug effects ; Biofilms/*drug effects ; Biological Products/chemistry/*pharmacology ; Carbapenems/*pharmacology ; Escherichia coli/*drug effects/*physiology ; Flavonoids/chemistry ; Male ; Microbial Sensitivity Tests ; Models, Biological ; Models, Molecular ; Molecular Conformation ; Molecular Docking Simulation ; Phenols/chemistry ; Plant Extracts/chemistry/*pharmacology ; Quorum Sensing/*drug effects ; Rats ; *beta-Lactam Resistance ; }, abstract = {The multi-drug resistance offered by Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria) against third line antibiotics can be attributed towards its ability to develop biofilm. Such process involves adhesion and quorum-sensing induced colonization leading to biomass development. The present study explored the anti-adhesion, anti-quorum sensing and anti-biofilm potential of 05 pre-standardized potent herbals. Berberis aristata (PTRC-2111-A) exhibited maximum potential in all these activities i.e. 91.3% ± 0.05% (Anti-adhesion), 96.06% ± 0.05% (Anti-Quorum sensing) and 51.3% ± 0.07% (Anti-Biofilm formation) respectively. Camellia sinensis (PTRC-31911-A) showed both anti-adhesion (84.1% ± 0.03%) and anti-quorum sensing (90.0%) potential while Holarrhena antidysenterica (PTRC-8111-A) showed only anti-quorum sensing potential as compared to standards/antibiotics. These findings were in line with the molecular docking analysis of phytoligands against Lux S and Pilin receptors. Furthermore, the pairwise correlation analysis of the tested activities with qualitative, quantitative and bioactivity functional descriptors revealed that an increased content of alkaloid, moderate content of flavonoids and decreased content of tannins supported all the three activities. In addition, nitric oxide and superoxide scavenging activity were found to be correlated with anti-quorum sensing activity. The findings indicated clearly that B. aristata (Family: Berberidaceae) and C. sinensis (Family: Theaceae) were potent herbal leads with significant therapeutic potential which further needs to be explored at pre-clinical level in the future.}, } @article {pmid26790937, year = {2016}, author = {Pereyra, EA and Picech, F and Renna, MS and Baravalle, C and Andreotti, CS and Russi, R and Calvinho, LF and Diez, C and Dallard, BE}, title = {Detection of Staphylococcus aureus adhesion and biofilm-producing genes and their expression during internalization in bovine mammary epithelial cells.}, journal = {Veterinary microbiology}, volume = {183}, number = {}, pages = {69-77}, doi = {10.1016/j.vetmic.2015.12.002}, pmid = {26790937}, issn = {1873-2542}, mesh = {Animals ; Bacterial Adhesion/*genetics ; Bacterial Typing Techniques ; *Biofilms ; Cattle ; Epithelial Cells/microbiology ; Female ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial/*genetics ; Mammary Glands, Animal/cytology/microbiology ; Mastitis, Bovine/*microbiology ; Phylogeny ; Staphylococcal Infections/microbiology/*veterinary ; Staphylococcus aureus/classification/genetics/*physiology ; }, abstract = {Staphylococcus aureus is one of the most prevalent pathogens isolated from bovine mastitis, causing chronic intramammary infections (IMI) that limit profitable dairying. The course of infection is often associated with factors both related to the host and the bacterium. Aims of this study were to select S. aureus isolates from bovine IMI with different genotypic profiles harboring genes involved in adherence and biofilm production, to determine the behavior of these strains in contact with bovine mammary epithelial cells (MAC-T) and the expression of those genes during bacterial-cell early interactions. The genetic diversity of 20 S. aureus strains that were isolated from milk samples taken from cows with persistent-P and non-persistent-NP IMI was high, discriminated into 13 fingerprint groups. The occurrence of genes coding for S. aureus surface proteins (clfA, clfB, fnbA, fnbB, fib, cna) and biofilm formation (icaA, icaD, icaC, bap) and in vitro biofilm-forming ability was not related to strain clinical origin (NP or P). Internalization of S. aureus into MAC-T cells was strain-dependent and internalized bacteria overexpressed adherence and biofilm-forming genes compared with those that remained in the supernatant of co-cultures; particularly those genes encoding FnBPs and IcaD. Strains yielding highest invasion percentages were those able to overexpress fnBP, irrespectively of the presence of other evaluated genes. Strains from NP IMI showed a greater multiplication capacity in vitro compared with strains from P IMI. These results provide new insights about S. aureus differential gene expression of adhesion-internalization factors during early interaction with mammary epithelial cells.}, } @article {pmid26790928, year = {2016}, author = {Xie, F and Li, G and Zhang, W and Zhang, Y and Zhou, L and Liu, S and Liu, S and Wang, C}, title = {Outer membrane lipoprotein VacJ is required for the membrane integrity, serum resistance and biofilm formation of Actinobacillus pleuropneumoniae.}, journal = {Veterinary microbiology}, volume = {183}, number = {}, pages = {1-8}, doi = {10.1016/j.vetmic.2015.11.021}, pmid = {26790928}, issn = {1873-2542}, mesh = {Actinobacillus pleuropneumoniae/genetics/*pathogenicity/*physiology ; Amino Acid Sequence ; Animals ; Anti-Infective Agents/pharmacology ; Bacterial Outer Membrane Proteins/genetics/*metabolism/ultrastructure ; *Biofilms ; Cell Membrane/genetics ; Gene Deletion ; Microbial Viability/genetics ; Microscopy, Electron, Transmission ; Osmoregulation/genetics ; Recombinant Proteins/genetics/metabolism ; Sequence Alignment ; Serum/microbiology ; Swine ; }, abstract = {The outer membrane proteins of Actinobacillus pleuropneumoniae are mediators of infection, acting as targets for the host's defense system. The outer membrane lipoprotein VacJ is involved in serum resistance and intercellular spreading in several pathogenic bacteria. To investigate the role of VacJ in the pathogenicity of Actinobacillus pleuropneumoniae, the vacJ gene-deletion mutant MD12 ΔvacJ was constructed. The increased susceptibility to KCl, SDS plus EDTA, and several antibiotics in the MD12ΔvacJ mutant suggested that the stability of the outer membrane was impaired as a result of the mutation in the vacJ gene. The increased NPN fluorescence and significant cellular morphological variation in the MD12ΔvacJ mutant further demonstrated the crucial role of the VacJ lipoprotein in maintaining the outer membrane integrity of A. pleuropneumoniae. In addition, the MD12ΔvacJ mutant exhibited decreased survival from the serum and complement killing compared to the wild-type strain. Interestingly, the MD12ΔvacJ mutant showed reduced biofilm formation compared to the wild-type strain. To our knowledge, this is the first description of the VacJ lipoprotein contributing to bacterial biofilm formation. The data presented in this study illustrate the important role of the VacJ lipoprotein in the maintenance of cellular integrity, serum resistance, and biofilm formation in A. pleuropneumoniae.}, } @article {pmid26789700, year = {2016}, author = {Young, B and Delatolla, R and Ren, B and Kennedy, K and Laflamme, E and Stintzi, A}, title = {Pilot-scale tertiary MBBR nitrification at 1°C: characterization of ammonia removal rate, solids settleability and biofilm characteristics.}, journal = {Environmental technology}, volume = {37}, number = {16}, pages = {2124-2132}, doi = {10.1080/09593330.2016.1143037}, pmid = {26789700}, issn = {1479-487X}, mesh = {Ammonia/analysis/*chemistry/*isolation & purification ; *Biofilms ; *Bioreactors ; Cold Temperature ; Kinetics ; Nitrification ; Pilot Projects ; }, abstract = {Pilot-scale moving bed biofilm reactor (MBBR) is used to investigate the kinetics and biofilm response of municipal, tertiary nitrification at 1°C. The research demonstrates that significant rates of tertiary MBBR nitrification are attainable and stable for extended periods of operation at 1°C, with a maximum removal rate of 230 gN/m(3) d at 1°C. At conventional nitrogen loading rates, low ammonia effluent concentrations below 5 mg-N/L were achieved at 1°C. The biofilm thickness and dry weight biofilm mass (massdw) were shown to be stable, with thickness values showing a correlation to the protein/polysaccharide ratio of the biofilm extracellular polymeric substances. Lastly, tertiary MBBR nitrification is shown to increase the effluent suspended solids concentrations by approximately 3 mg total suspended solids /L, with 19-60% of effluent solids being removed after 30 min of settling. The settleability of the effluent solids was shown to be correlated to the nitrogen loading of the MBBR system.}, } @article {pmid26788425, year = {2016}, author = {Yoshioka, S and Newell, PD}, title = {Disruption of de novo purine biosynthesis in Pseudomonas fluorescens Pf0-1 leads to reduced biofilm formation and a reduction in cell size of surface-attached but not planktonic cells.}, journal = {PeerJ}, volume = {4}, number = {}, pages = {e1543}, pmid = {26788425}, issn = {2167-8359}, abstract = {Pseudomonas fluorescens Pf0-1 is one of the model organisms for biofilm research. Our previous transposon mutagenesis study suggested a requirement for the de novo purine nucleotide biosynthesis pathway for biofilm formation by this organism. This study was performed to verify that observation and investigate the basis for the defects in biofilm formation shown by purine biosynthesis mutants. Constructing deletion mutations in 8 genes in this pathway, we found that they all showed reductions in biofilm formation that could be partly or completely restored by nucleotide supplementation or genetic complementation. We demonstrated that, despite a reduction in biofilm formation, more viable mutant cells were recovered from the surface-attached population than from the planktonic phase under conditions of purine deprivation. Analyses using scanning electron microscopy revealed that the surface-attached mutant cells were 25 ∼ 30% shorter in length than WT, which partly explains the reduced biomass in the mutant biofilms. The laser diffraction particle analyses confirmed this finding, and further indicated that the WT biofilm cells were smaller than their planktonic counterparts. The defects in biofilm formation and reductions in cell size shown by the mutants were fully recovered upon adenine or hypoxanthine supplementation, indicating that the purine shortages caused reductions in cell size. Our results are consistent with surface attachment serving as a survival strategy during nutrient deprivation, and indicate that changes in the cell size may be a natural response of P. fluorescens to growth on a surface. Finally, cell sizes in WT biofilms became slightly smaller in the presence of exogenous adenine than in its absence. Our findings suggest that purine nucleotides or related metabolites may influence the regulation of cell size in this bacterium.}, } @article {pmid26785934, year = {2016}, author = {Lee, JH and Kim, YG and Lee, K and Kim, CJ and Park, DJ and Ju, Y and Lee, JC and Wood, TK and Lee, J}, title = {Streptomyces-derived actinomycin D inhibits biofilm formation by Staphylococcus aureus and its hemolytic activity.}, journal = {Biofouling}, volume = {32}, number = {1}, pages = {45-56}, doi = {10.1080/08927014.2015.1125888}, pmid = {26785934}, issn = {1029-2454}, mesh = {Anti-Bacterial Agents/pharmacology ; *Biofilms/drug effects/growth & development ; Biofouling/*prevention & control ; Dactinomycin/*pharmacology ; Hemolysis/*drug effects ; Humans ; *Staphylococcus aureus/drug effects/physiology ; Streptomyces/physiology ; Surface-Active Agents/pharmacology ; }, abstract = {Staphylococcus aureus is a versatile human pathogen that produces diverse virulence factors, and its biofilm cells are difficult to eradicate due to their inherent ability to tolerate antibiotics. The anti-biofilm activities of the spent media of 252 diverse endophytic microorganisms were investigated using three S. aureus strains. An attempt was made to identify anti-biofilm compounds in active spent media and to assess their anti-hemolytic activities and hydrophobicities in order to investigate action mechanisms. Unlike other antibiotics, actinomycin D (0.5 μg ml(-1)) from Streptomyces parvulus significantly inhibited biofilm formation by all three S. aureus strains. Actinomycin D inhibited slime production in S. aureus and it inhibited hemolysis by S. aureus and caused S. aureus cells to become less hydrophobic, thus supporting its anti-biofilm effect. In addition, surface coatings containing actinomycin D prevented S. aureus biofilm formation on glass surfaces. Given these results, FDA-approved actinomycin D warrants further attention as a potential antivirulence agent against S. aureus infections.}, } @article {pmid26782142, year = {2016}, author = {Castro, J and Machado, D and Cerca, N}, title = {Escherichia coli and Enterococcus faecalis are able to incorporate and enhance a pre-formed Gardnerella vaginalis biofilm.}, journal = {Pathogens and disease}, volume = {74}, number = {3}, pages = {}, doi = {10.1093/femspd/ftw007}, pmid = {26782142}, issn = {2049-632X}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Enterococcus faecalis/growth & development/*pathogenicity ; Escherichia coli/growth & development/*pathogenicity ; Female ; Gardnerella vaginalis/*growth & development/*pathogenicity ; Humans ; Microbial Consortia/physiology ; Microscopy, Fluorescence ; Symbiosis/physiology ; Urinary Tract Infections/microbiology ; Vagina/*microbiology ; Vaginosis, Bacterial/microbiology ; }, abstract = {Gardnerella vaginalis is the most frequent microorganism found in bacterial vaginosis (BV), while Escherichia coli and Enterococcus faecalis are amongst the most frequent pathogens found in urinary tract infections (UTIs). This study aimed to evaluate possible interactions between UTIs pathogens and G. vaginalis using an in vitro dual-species biofilm model. Our results showed that dual-species biofilms reached significantly higher bacterial concentration than monospecies biofilms. Moreover, visualization of dual-populations species in the biofilms, using the epifluorescence microscopy, revealed that all of the urogenital pathogens coexisted with G. vaginalis. In conclusion, our work demonstrates that uropathogens can incorporate into mature BV biofilms.}, } @article {pmid26779572, year = {2016}, author = {Wang, Z and Morales-Acosta, MD and Li, S and Liu, W and Kanai, T and Liu, Y and Chen, YN and Walker, FJ and Ahn, CH and Leblanc, RM and Yan, EC}, title = {A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface.}, journal = {Chemical communications (Cambridge, England)}, volume = {52}, number = {14}, pages = {2956-2959}, pmid = {26779572}, issn = {1364-548X}, support = {R56 DK105381/DK/NIDDK NIH HHS/United States ; 1R56DK105381-01/DK/NIDDK NIH HHS/United States ; }, mesh = {Air ; Amides/*chemistry ; *Biofilms ; Microscopy, Atomic Force ; Proteins/*chemistry ; Spectrum Analysis/*methods ; Vibration ; Water ; }, abstract = {We characterized BslA, a bacterial biofilm protein, at the air/water interface using vibrational sum frequency generation spectroscopy and observed one of the sharpest amide I bands ever reported. Combining methods of surface pressure measurements, thin film X-ray reflectivity, and atomic force microscopy, we showed extremely ordered BslA at the interface.}, } @article {pmid26779171, year = {2015}, author = {Duanis-Assaf, D and Steinberg, D and Chai, Y and Shemesh, M}, title = {The LuxS Based Quorum Sensing Governs Lactose Induced Biofilm Formation by Bacillus subtilis.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1517}, pmid = {26779171}, issn = {1664-302X}, abstract = {Bacillus species present a major concern in the dairy industry as they can form biofilms in pipelines and on surfaces of equipment and machinery used in the entire line of production. These biofilms represent a continuous hygienic problem and can lead to serious economic losses due to food spoilage and equipment impairment. Biofilm formation by Bacillus subtilis is apparently dependent on LuxS quorum sensing (QS) by Autoinducer-2 (AI-2). However, the link between sensing environmental cues and AI-2 induced biofilm formation remains largely unknown. The aim of this study is to investigate the role of lactose, the primary sugar in milk, on biofilm formation by B. subtilis and its possible link to QS processes. Our phenotypic analysis shows that lactose induces formation of biofilm bundles as well as formation of colony type biofilm. Furthermore, using reporter strain assays, we observed an increase in AI-2 production by B. subtilis in response to lactose in a dose dependent manner. Moreover, we found that expression of eps and tapA operons, responsible for extracellular matrix synthesis in B. subtilis, were notably up-regulated in response to lactose. Importantly, we also observed that LuxS is essential for B. subtilis biofilm formation in the presence of lactose. Overall, our results suggest that lactose may induce biofilm formation by B. subtilis through the LuxS pathway.}, } @article {pmid26779167, year = {2015}, author = {Zhou, YF and Shi, W and Yu, Y and Tao, MT and Xiong, YQ and Sun, J and Liu, YH}, title = {Pharmacokinetic/Pharmacodynamic Correlation of Cefquinome Against Experimental Catheter-Associated Biofilm Infection Due to Staphylococcus aureus.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1513}, pmid = {26779167}, issn = {1664-302X}, abstract = {Biofilm formations play an important role in Staphylococcus aureus pathogenesis and contribute to antibiotic treatment failures in biofilm-associated infections. The aim of this study was to evaluate the pharmacokinetic/pharmacodynamic (PK/PD) profiles of cefquinome against an experimental catheter-related biofilm model due to S. aureus, including three clinical isolates and one non-clinical isolate. The minimal inhibitory concentration (MIC), minimal biofilm inhibitory concentration (MBIC), biofilm bactericidal concentration (BBC), minimal biofilm eradication concentration (MBEC) and biofilm prevention concentration (BPC) and in vitro time-kill curves of cefquinome were studied in both planktonic and biofilm cells of study S. aureus strains. The in vivo post-antibiotic effects (PAEs), PK profiles and efficacy of cefquinome were performed in the catheter-related biofilm infection model in murine. A sigmoid E max model was utilized to determine the PK/PD index that best described the dose-response profiles in the model. The MICs and MBICs of cefquinome for the four S. aureus strains were 0.5 and 16 μg/mL, respectively. The BBCs (32-64 μg/mL) and MBECs (64-256 μg/mL) of these study strains were much higher than their corresponding BPC values (1-2 μg/mL). Cefquinome showed time-dependent killing both on planktonic and biofilm cells, but produced much shorter PAEs in biofilm infections. The best-correlated PK/PD parameters of cefquinome for planktonic and biofilm cells were the duration of time that the free drug level exceeded the MIC (fT > MIC, R (2) = 96.2%) and the MBIC (fT > MBIC, R (2) = 94.7%), respectively. In addition, the AUC24h/MBIC of cefquinome also significantly correlated with the anti-biofilm outcome in this model (R (2) = 93.1%). The values of AUC24h/MBIC for biofilm-static and 1-log10-unit biofilm-cidal activity were 22.8 and 35.6 h; respectively. These results indicate that the PK/PD profiles of cefquinome could be used as valuable guidance for effective dosing regimens treating S. aureus biofilm-related infections.}, } @article {pmid26779121, year = {2015}, author = {Srinandan, CS and Elango, M and Gnanadhas, DP and Chakravortty, D}, title = {Infiltration of Matrix-Non-producers Weakens the Salmonella Biofilm and Impairs Its Antimicrobial Tolerance and Pathogenicity.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1468}, pmid = {26779121}, issn = {1664-302X}, abstract = {Bacterial biofilms display a collective lifestyle, wherein the cells secrete extracellular polymeric substances (EPS) that helps in adhesion, aggregation, stability, and to protect the bacteria from antimicrobials. We asked whether the EPS could act as a public good for the biofilm and observed that infiltration of cells that do not produce matrix components weakened the biofilm of Salmonella enterica serovar Typhimurium. EPS production was costly for the producing cells, as indicated by a significant reduction in the fitness of wild type (WT) cells during competitive planktonic growth relative to the non-producers. Infiltration frequency of non-producers in the biofilm showed a concomitant decrease in overall productivity. It was apparent in the confocal images that the non-producing cells benefit from the EPS produced by the Wild Type (WT) to stay in the biofilm. The biofilm containing non-producing cells were more significantly susceptible to sodium hypochlorite and ciprofloxacin treatment than the WT biofilm. Biofilm infiltrated with non-producers delayed the pathogenesis, as tested in a murine model. The cell types were spatially assorted, with non-producers being edged out in the biofilm. However, cellulose was found to act as a barrier to keep the non-producers away from the WT microcolony. Our results show that the infiltration of non-cooperating cell types can substantially weaken the biofilm making it vulnerable to antibacterials and delay their pathogenesis. Cellulose, a component of EPS, was shown to play a pivotal role of acting as the main public good, and to edge-out the non-producers away from the cooperating microcolony.}, } @article {pmid26776731, year = {2016}, author = {Hazan, R and Que, YA and Maura, D and Strobel, B and Majcherczyk, PA and Hopper, LR and Wilbur, DJ and Hreha, TN and Barquera, B and Rahme, LG}, title = {Auto Poisoning of the Respiratory Chain by a Quorum-Sensing-Regulated Molecule Favors Biofilm Formation and Antibiotic Tolerance.}, journal = {Current biology : CB}, volume = {26}, number = {2}, pages = {195-206}, pmid = {26776731}, issn = {1879-0445}, support = {R33AI105902/AI/NIAID NIH HHS/United States ; R56AI063433/AI/NIAID NIH HHS/United States ; R21 AI105902/AI/NIAID NIH HHS/United States ; R33 AI105902/AI/NIAID NIH HHS/United States ; R01 AI063433/AI/NIAID NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Electron Transport/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Hydroxyquinolines/pharmacology ; Mitochondrial Membranes/metabolism ; Pseudomonas aeruginosa/drug effects/*physiology ; Quorum Sensing/drug effects/physiology ; }, abstract = {Bacterial programmed cell death and quorum sensing are direct examples of prokaryote group behaviors, wherein cells coordinate their actions to function cooperatively like one organism for the benefit of the whole culture. We demonstrate here that 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), a Pseudomonas aeruginosa quorum-sensing-regulated low-molecular-weight excreted molecule, triggers autolysis by self-perturbing the electron transfer reactions of the cytochrome bc1 complex. HQNO induces specific self-poisoning by disrupting the flow of electrons through the respiratory chain at the cytochrome bc1 complex, causing a leak of reducing equivalents to O2 whereby electrons that would normally be passed to cytochrome c are donated directly to O2. The subsequent mass production of reactive oxygen species (ROS) reduces membrane potential and disrupts membrane integrity, causing bacterial cell autolysis and DNA release. DNA subsequently promotes biofilm formation and increases antibiotic tolerance to beta-lactams, suggesting that HQNO-dependent cell autolysis is advantageous to the bacterial populations. These data identify both a new programmed cell death system and a novel role for HQNO as a critical inducer of biofilm formation and antibiotic tolerance. This newly identified pathway suggests intriguing mechanistic similarities with the initial mitochondrial-mediated steps of eukaryotic apoptosis.}, } @article {pmid26775102, year = {2016}, author = {Zhong, Y and Li, X and Yang, Q and Wang, D and Yao, F and Li, X and Zhao, J and Xu, Q and Zhang, C and Zeng, G}, title = {Complete bromate and nitrate reduction using hydrogen as the sole electron donor in a rotating biofilm-electrode reactor.}, journal = {Journal of hazardous materials}, volume = {307}, number = {}, pages = {82-90}, doi = {10.1016/j.jhazmat.2015.12.053}, pmid = {26775102}, issn = {1873-3336}, mesh = {Bacteria/metabolism ; Biofilms ; *Bioreactors ; Bromates/*metabolism ; Carbon ; Electrodes ; Electrons ; Hydrogen/*metabolism ; Nitrates/*metabolism ; Oxidation-Reduction ; }, abstract = {Simultaneous reduction of bromate and nitrate was investigated using a rotating biofilm-electrode reactor (RBER) with graphite carbon (GC) rods as anode and activated carbon fiber (ACF) bonded with steel ring as cathode. In RBER, the community of denitrifying bacteria immobilized on the cathode surface could completely utilize hydrogen (H2) as the electron donor, which was internally produced by the electrolysis of water. The short-term test confirmed that the RBER system could reduce 150-800μg/L bromate to below 10μg/L under autotrophic conditions. The reduced bromate was considered to be roughly equivalent to the amount of bromide in effluent, indicating that bromate was completely reduced to bromide without accumulation of by-products. The long-term test (over 120 days) showed that the removal fluxes of bromate and nitrate could be improved by increasing the electric current and decreasing the hydraulic retention time (HRT). But nitrite in effluent was significantly accumulated when the electric current was beyond 10mA and the HRT was less than 6h. The maximum bromate reduction rate estimated by the Monod equation was 109.12μg/Lh when the electric current was 10mA and HRT was 12h. It was proposed that the electron transfer process in RBER produced H2 on the surface of the ACF cathode, and the microbial cultures attached closely on the cathode which could completely utilize H2 as electron donors for reduction of bromate and nitrate.}, } @article {pmid26774522, year = {2016}, author = {Kolpen, M and Mousavi, N and Sams, T and Bjarnsholt, T and Ciofu, O and Moser, C and Kühl, M and Høiby, N and Jensen, PØ}, title = {Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment.}, journal = {International journal of antimicrobial agents}, volume = {47}, number = {2}, pages = {163-167}, doi = {10.1016/j.ijantimicag.2015.12.005}, pmid = {26774522}, issn = {1872-7913}, mesh = {Aerobiosis ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/*pharmacology ; *Hydrostatic Pressure ; Microbial Viability/*drug effects ; Oxygen/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; }, abstract = {Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechanisms affecting antibiotic effectiveness on biofilms remain unclear, accumulating evidence suggests that the efficacy of several bactericidal antibiotics such as ciprofloxacin is enhanced by stimulation of the aerobic respiration of pathogens, and that lack of O2 increases their tolerance. Reoxygenation of O2-depleted biofilms may thus improve susceptibility to ciprofloxacin possibly by restoring aerobic respiration. We tested such a strategy using reoxygenation of O2-depleted P. aeruginosa strain PAO1 agarose-embedded biofilms by hyperbaric oxygen treatment (HBOT) (100% O2, 2.8bar), enhancing the diffusive supply for aerobic respiration during ciprofloxacin treatment. This proof-of-principle study demonstrates that biofilm reoxygenation by HBOT can significantly enhance the bactericidal activity of ciprofloxacin on P. aeruginosa. Combining ciprofloxacin treatment with HBOT thus clearly has potential to improve the treatment of P. aeruginosa biofilm infections.}, } @article {pmid26773487, year = {2016}, author = {Costa, D and Girardot, M and Bertaux, J and Verdon, J and Imbert, C}, title = {Efficacy of dental unit waterlines disinfectants on a polymicrobial biofilm.}, journal = {Water research}, volume = {91}, number = {}, pages = {38-44}, doi = {10.1016/j.watres.2015.12.053}, pmid = {26773487}, issn = {1879-2448}, mesh = {Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Dental Disinfectants/*pharmacology ; *Disinfection ; Pseudomonas aeruginosa/*drug effects/physiology ; Tubulina/*drug effects/physiology ; }, abstract = {Due to their high surface-volume ratio, their laminar flow and frequent stagnation periods, dental unit waterlines (DUWL) foster the attachment of microorganisms and the development of biofilm, resulting in the continuous contamination of the outlet water from dental units; this contamination may be responsible for a potential risk of infection due to the exposure of patients and medical staff to droplet inhalation or splashed water. In this study, the anti-biofilm activity of three disinfectants recommended by dental unit manufacturers -Calbenium(©), Oxygenal 6(©) and Sterispray(©) - was evaluated. A dynamic model simulating DUWL conditions was developed and polymicrobial biofilms containing bacteria (Pseudomonas aeruginosa), fungi (Candida albicans) and Free Living Amoeba (FLA: Vermamoeba vermiformis) were allowed to form. The ability of disinfectants to reduce biofilm formation or to eradicate an already formed biofilm was evaluated. Results showed the various effects of the tested disinfectants according to their composition, concentration and the targeted species. V. vermiformis was resistant to disinfectants, regardless of the tested concentrations and the concentrations recommended by manufacturers were not the most appropriate. Results also showed that Calbenium(©) was the most effective disinfectant to reduce already formed biofilms; its maximum efficiency was observed from 0.5% on both P. aeruginosa and C. albicans compared to 2 and 3% respectively for Sterispray(©). The maximum efficiency of Oxygenal(©) was observed from 3% on P. aeruginosa but Oxygenal(©) was unable to totally eliminate C. albicans in the tested conditions, contrary to other disinfectants. Calbenium(©) was able to prevent biofilm formation efficiently even if it displayed no prophylactic activity against V. vermiformis. Overall, the FLA survival may contribute to maintaining other species. Finally the tested disinfectants were partially active against sessile microorganisms and more suitable concentrations could be used to increase their efficacy. Their use in a prophylactic rather than curative way should be recommended.}, } @article {pmid26772652, year = {2016}, author = {Dutton, LC and Jenkinson, HF and Lamont, RJ and Nobbs, AH}, title = {Role of Candida albicans secreted aspartyl protease Sap9 in interkingdom biofilm formation.}, journal = {Pathogens and disease}, volume = {74}, number = {3}, pages = {}, pmid = {26772652}, issn = {2049-632X}, support = {R01 DE016690/DE/NIDCR NIH HHS/United States ; }, mesh = {Adult ; Aspartic Acid Endopeptidases/genetics/*metabolism ; Biofilms/*growth & development ; Candida albicans/genetics/*metabolism/pathogenicity ; Enterococcus faecalis/*metabolism ; Fungal Proteins/genetics/*metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions ; Hyphae/metabolism ; Microbial Interactions/physiology ; Microscopy, Confocal ; Mouth/microbiology ; Streptococcus gordonii/*metabolism ; Streptococcus mutans/*metabolism ; }, abstract = {The fungus Candida albicans colonizes oral cavity surfaces and is carried by up to 60% of human populations. Biofilm development by C. albicans may be modulated by oral streptococci, such as Streptococcus gordonii, S. oralis or S. mutans, so as to augment pathogenicity. In this study we sought to determine if the cell wall-associated secreted aspartyl proteinase Sap9 was necessary for hyphal adhesin functions associated with biofilm community development. A sap9Δ mutant of C. albicans SC5314 formed biofilms that were flatter, and contained fewer blastospores and more hyphal filaments than the parent strain. This phenotypic difference was accentuated under flow (shear) conditions and in the presence of S. gordonii. Dual-species biofilms of C. albicans sap9Δ with S. oralis, S. sanguinis, S. parasanguinis, S. mutans and Enterococcus faecalis all contained more matted hyphae and more bacteria bound to substratum compared to C. albicans wild type. sap9Δ mutant hyphae showed significantly increased cell surface hydrophobicity, ∼25% increased levels of binding C. albicans cell wall protein Als3, and reduced interaction with Eap1, implicating Sap9 in fungal cell-cell recognition. These observations suggest that Sap9 is associated with protein-receptor interactions between fungal cells, and with interkingdom communication in the formation of polymicrobial biofilm communities.}, } @article {pmid26771168, year = {2016}, author = {Fabbri, S and Johnston, DA and Rmaile, A and Gottenbos, B and De Jager, M and Aspiras, M and Starke, EM and Ward, MT and Stoodley, P}, title = {Streptococcus mutans biofilm transient viscoelastic fluid behaviour during high-velocity microsprays.}, journal = {Journal of the mechanical behavior of biomedical materials}, volume = {59}, number = {}, pages = {197-206}, doi = {10.1016/j.jmbbm.2015.12.012}, pmid = {26771168}, issn = {1878-0180}, mesh = {Animals ; *Biofilms ; Streptococcus mutans/*physiology ; Swine ; *Viscosity ; Water ; }, abstract = {Using high-speed imaging we assessed Streptococcus mutans biofilm-fluid interactions during exposure to a 60-ms microspray burst with a maximum exit velocity of 51m/s. S. mutans UA159 biofilms were grown for 72h on 10mm-length glass slides pre-conditioned with porcine gastric mucin. Biofilm stiffness was measured by performing uniaxial-compression tests. We developed an in-vitro interproximal model which allowed the parallel insertion of two biofilm-colonized slides separated by a distance of 1mm and enabled high-speed imaging of the removal process at the surface. S. mutans biofilms were exposed to either a water microspray or an air-only microburst. High-speed videos provided further insight into the mechanical behaviour of biofilms as complex liquids and into high-shear fluid-biofilm interaction. We documented biofilms extremely transient fluid behaviour when exposed to the high-velocity microsprays. The presence of time-dependent recoil and residual deformation confirmed the pivotal role of viscoelasticity in biofilm removal. The air-only microburst was effective enough to remove some of the biofilm but created a smaller clearance zone underlying the importance of water and the air-water interface of drops moving over the solid surface in the removal process. Confocal and COMSTAT analysis showed the high-velocity water microspray caused up to a 99.9% reduction in biofilm thickness, biomass and area coverage, within the impact area.}, } @article {pmid26770255, year = {2015}, author = {Filocamo, A and Bisignano, C and Mandalari, G and Navarra, M}, title = {In Vitro Antimicrobial Activity and Effect on Biofilm Production of a White Grape Juice (Vitis vinifera) Extract.}, journal = {Evidence-based complementary and alternative medicine : eCAM}, volume = {2015}, number = {}, pages = {856243}, pmid = {26770255}, issn = {1741-427X}, abstract = {Background. The aim of the present study was to evaluate the antimicrobial effect of a white grape juice extract (WGJe) against a range of Gram-positive and Gram-negative bacteria, yeasts, and the fungus Aspergillus niger. WGJe was also tested on the production of bacterial biofilms in vitro. Results. WGJe inhibited in vitro most Gram-positive bacteria tested, Staphylococcus aureus ATCC 6538P being the most sensitive strain (MIC values of 3.9 μg/mL). The effect was bactericidal at the concentration of 500 μg/mL. Amongst the Gram-negative bacteria, Escherichia coli was the only susceptible strain (MIC and MBC of 2000 μg/mL). No effect on the growth of Candida sp. and the fungus Aspergillus niger was detected (MIC values > 2000 μg/mL). WGJe inhibited the biofilms formation of E. coli and Pseudomonas aeruginosa with a dose-dependent effect. Conclusions. WGJe exerted both bacteriostatic and bactericidal activity in vitro. The presented results could be used to develop novel strategies for the treatment of skin infections and against potential respiratory pathogens.}, } @article {pmid26769942, year = {2016}, author = {Pinto, AJ and Sharp, JO and Yoder, MJ and Almstrand, R}, title = {Draft Genome Sequences of Two Novel Acidimicrobiaceae Members from an Acid Mine Drainage Biofilm Metagenome.}, journal = {Genome announcements}, volume = {4}, number = {1}, pages = {}, pmid = {26769942}, issn = {2169-8287}, abstract = {Bacteria belonging to the family Acidimicrobiaceae are frequently encountered in heavy metal-contaminated acidic environments. However, their phylogenetic and metabolic diversity is poorly resolved. We present draft genome sequences of two novel and phylogenetically distinct Acidimicrobiaceae members assembled from an acid mine drainage biofilm metagenome.}, } @article {pmid26768371, year = {2016}, author = {Pesee, S and Angkananuwat, C and Tancharoensukjit, S and Muanmai, S and Sirivan, P and Bubphawas, M and Tanarerkchai, N}, title = {In vitro activity of Caspofungin combined with Fluconazole on mixed Candida albicans and Candida glabrata biofilm.}, journal = {Medical mycology}, volume = {54}, number = {4}, pages = {384-393}, doi = {10.1093/mmy/myv108}, pmid = {26768371}, issn = {1460-2709}, mesh = {Antifungal Agents/*pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects ; Candida glabrata/*drug effects ; Caspofungin ; Drug Combinations ; Echinocandins/*pharmacology ; Fluconazole/*pharmacology ; Lipopeptides/*pharmacology ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {The objective of this study was to evaluate the antifungal effect of caspofungin (CAS) combined with fluconazole (FLU) on the biofilm biomass and cultivable viability and microstructure of Candida albicans and Candida glabrata mixed biofilm in vitro.Biofilms were formed in a 96-well microtiter plate for crystal violet assay and colony forming unit (CFU) method and grown on plastic coverslip disks for scanning electron microscopy. MIC50 of CAS and FLU against single Candida spp.and mixed Candida spp.biofilms were evaluated using crystal violet assay. Additional,C. albicans and C. glabrata mixed biofilms were incubated with subinhibitory CAS concentration plus FLU and their percentages of Candida biofilm reduction were calculated. We found that percentages of biofilm reduction were significantly decreased when CAS at 0.25MIC and FLU (0.25 or 0.5MIC) were combined (P< .05) but not different when CAS at 0.5 MIC combined with FLU at 0.25 or 0.5MIC, compared to CAS treatment alone. Structural analyses revealed that CAS/FLU combination-treated biofilms showed less hyphae and blastospores with some aberrant cells compared to control group. Although it was evident that a greater CFU of Candida glabrata were demonstrated in every group, the total viable cells derived from CAS/FLU combination-treated biofilms at any ratio were not significantly different from positive control. Overall, CAS/FLU combinations appeared to affect the quantity and cell architecture, but number of viable cell, of Candida albicans and Candida glabrata mixed biofilm. This antifungal effect was CAS concentration dependent.}, } @article {pmid26766360, year = {2016}, author = {Wang, X and Utsumi, M and Gao, Y and Li, Q and Tian, X and Shimizu, K and Sugiura, N}, title = {Influences of metal ions on microcystin-LR degradation capacity and dynamics in microbial distribution of biofilm collected from water treatment plant nearby Kasumigaura Lake.}, journal = {Chemosphere}, volume = {147}, number = {}, pages = {230-238}, doi = {10.1016/j.chemosphere.2015.12.067}, pmid = {26766360}, issn = {1879-1298}, mesh = {*Bacterial Physiological Phenomena ; Biodegradation, Environmental ; *Biofilms ; Japan ; Lakes ; Marine Toxins ; Metals, Heavy/metabolism ; Microcystins/*metabolism ; *Water Purification ; }, abstract = {Microcystins-LR (MC-LR) which is a kind of potent hepatotoxin for humans and wildlife can be biodegraded by microbial community. In this study, the capacity of biofilm in degrading MC-LR was investigated with and without additional metal ions (Mn(2+), Zn(2+) and Cu(2+)) at the concentration of 1 mg L(-1). The results indicated that the degradation rate of MC-LR by biofilm was inhibited by introduced Mn(2+) and Cu(2+) during the whole culture period. MC-LR cannot be degraded until a period of culture time passed both in the cases with Zn(2+) and Cu(2+) (2 and 8 days for Zn(2+) and Cu(2+), respectively). The results of mlrA gene analysis showed that the abundance of MC-LR degradation bacteria (MCLDB) in the microbial community under Mn(2+) condition was generally lower than that under no additional metal ion condition. Meanwhile, a two days lag phase for the proliferation of MCLDB occurred after introducing Zn(2+). And a dynamic change of MCLDB from Cu(2+) inhibited species to Cu(2+) promoted species was observed under Cu(2+) condition. The maximum ratio of MCLDB to overall bacteria under various conditions during culture process was found to follow the tendency as: Cu(2+) > Zn(2+) ≈ no additional metal ion (Control) > Mn(2+), suggesting the adverse effect of Mn(2+), no obvious effect of Zn(2+) and positive effect of Cu(2+) on the distribution ratio of MCLDB over the biofilm.}, } @article {pmid26765504, year = {2015}, author = {Marcinkiewicz, J and Stręk, P and Strus, M and Głowacki, R and Ciszek-Lenda, M and Zagórska-Świeży, K and Gawda, A and Tomusiak, A}, title = {Staphylococcus epidermidis and biofilm-associated neutrophils in chronic rhinosinusitis. A pilot study.}, journal = {International journal of experimental pathology}, volume = {96}, number = {6}, pages = {378-386}, pmid = {26765504}, issn = {1365-2613}, mesh = {Adult ; *Biofilms ; Biomarkers/analysis ; Chronic Disease ; Colony Count, Microbial ; Double-Blind Method ; Female ; Humans ; Male ; Microscopy, Electrochemical, Scanning ; Middle Aged ; Nasal Mucosa/immunology/*microbiology/ultrastructure ; Neutrophil Infiltration ; Neutrophils/enzymology/immunology/*microbiology ; Peroxidase/analysis ; Prospective Studies ; Rhinitis/diagnosis/immunology/*microbiology ; Severity of Illness Index ; Sinusitis/diagnosis/immunology/*microbiology ; Staphylococcal Infections/diagnosis/immunology/*microbiology ; Staphylococcus epidermidis/*growth & development/immunology/isolation & purification/ultrastructure ; }, abstract = {A key role of bacterial biofilm in the pathogenesis of chronic rhinosinusitis (CRS) with (CRSwNP) and without nasal polyps (CRSsNP) is commonly accepted. However, the impact of some bacterial species isolated from inflamed sinus mucosa on biofilm formation is unclear. In particular, the role of Staphylococcus epidermidis as aetiological agents of CRS is controversial. Moreover, the effect of biofilm formation on neutrophil infiltration and activity in CRSwNP calls for explanation. In this study, biofilms were found in three of 10 patients (mean age = 46 ± 14) with CRS undergoing endoscopic sinus surgery by means of scanning electron microscopy. Unexpectedly, S. epidermidis was the primary isolated bacteria and was also found to be present in all biofilm-positive mucosa specimens, indicating its pivotal role in the pathogenesis of severe chronic infections associated with biofilm formation. We have also measured the activity of myeloperoxidase (MPO), the most abundant neutrophil enzyme, to demonstrate the presence of neutrophils in the samples tested. Our present results show that the level of MPO in CRS associated with biofilm is lower than that without biofilm. It may suggest either a low number of neutrophils or the presence of a type of neutrophils with compromised antimicrobial activity, described as biofilm-associated neutrophils (BAN). Finally, we conclude that further studies with a large number of CRS cases should be performed to establish the association between S. epidermidis and other frequently isolated bacterial species from paranasal sinuses, with the severity of CRS, biofilm formation and the infiltration of BAN.}, } @article {pmid26763935, year = {2016}, author = {Lee, JH and Kim, YG and Yong Ryu, S and Lee, J}, title = {Calcium-chelating alizarin and other anthraquinones inhibit biofilm formation and the hemolytic activity of Staphylococcus aureus.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {19267}, pmid = {26763935}, issn = {2045-2322}, mesh = {Aniline Compounds/*pharmacology ; Anthraquinones/*pharmacology ; Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/drug effects ; Hemolysis/*drug effects ; Microbial Sensitivity Tests ; Staphylococcus aureus/*drug effects/*physiology ; Staphylococcus epidermidis/drug effects/physiology ; Transcriptome ; }, abstract = {Staphylococcal biofilms are problematic and play a critical role in the persistence of chronic infections because of their abilities to tolerate antimicrobial agents. Thus, the inhibitions of biofilm formation and/or toxin production are viewed as alternative means of controlling Staphylococcus aureus infections. Here, the antibiofilm activities of 560 purified phytochemicals were examined. Alizarin at 10 μg/ml was found to efficiently inhibit biofilm formation by three S. aureus strains and a Staphylococcus epidermidis strain. In addition, two other anthraquinones purpurin and quinalizarin were found to have antibiofilm activity. Binding of Ca(2+) by alizarin decreased S. aureus biofilm formation and a calcium-specific chelating agent suppressed the effect of calcium. These three anthraquinones also markedly inhibited the hemolytic activity of S. aureus, and in-line with their antibiofilm activities, increased cell aggregation. A chemical structure-activity relationship study revealed that two hydroxyl units at the C-1 and C-2 positions of anthraquinone play important roles in antibiofilm and anti-hemolytic activities. Transcriptional analyses showed that alizarin repressed the α-hemolysin hla gene, biofilm-related genes (psmα, rbf, and spa), and modulated the expressions of cid/lrg genes (the holin/antiholin system). These findings suggest anthraquinones, especially alizarin, are potentially useful for controlling biofilm formation and the virulence of S. aureus.}, } @article {pmid26762493, year = {2016}, author = {Kıvanç, SA and Kıvanç, M and Bayramlar, H}, title = {Microbiology of corneal wounds after cataract surgery: biofilm formation and antibiotic resistance patterns.}, journal = {Journal of wound care}, volume = {25}, number = {1}, pages = {12, 14-9}, doi = {10.12968/jowc.2016.25.1.12}, pmid = {26762493}, issn = {0969-0700}, mesh = {Aged ; Anti-Bacterial Agents/*administration & dosage ; Anti-Infective Agents, Local/*therapeutic use ; Biofilms/drug effects ; Cataract Extraction/adverse effects ; Cross-Sectional Studies ; Disinfectants ; Drug Resistance, Microbial ; Endophthalmitis/nursing/*prevention & control ; Eye Infections, Bacterial/nursing/*prevention & control ; Female ; Humans ; Male ; Middle Aged ; Ophthalmic Solutions/therapeutic use ; Phacoemulsification ; Postoperative Complications/nursing/*prevention & control ; Povidone-Iodine/*therapeutic use ; Visual Acuity ; }, abstract = {OBJECTIVE: To evaluate the bacterial flora of corneal wounds at the end of cataract surgery before intracameral antibiotic use and to determine agents to treat postoperative endophthalmitis, the potential for biofilm formation, and antibiotic resistance.

METHOD: This cross-sectional clinical study included patients who underwent cataract surgery using the phacoemulsification technique without any complications. The hemifacial skin, periocular area, eyelids and eyelashes were washed with 10% povidone-iodine and the conjunctiva was washed with 5% povidoneiodine before cataract surgery. After uncomplicated surgery, a wipe sample was taken from the bulbar conjunctival surface, corneal surface, and wound rim before administering intracameral antibiotics. All samples were plated on blood agar, MRS agar, M17 agar, calcium-lactate agar, plate-count agar, and Sabouraud-dextrose agar. Biofilm formation was evaluated by microtitre plates and the Congo red-agar method. Antimicrobial resistance patterns of isolates were determined by the agar-disk diffusion method.

RESULTS: We recruited 50 patients and studied 55 eyes, obtaining 34 isolates from the cultures of 16 eyes. Isolated organisms were coagulase-negative staphylococci (CoNS) (35.3%), Bacillus cereus (29.4%) and Pseudomonas spp. (5.9%). We obtained isolates from 64% of diabetic cases and 20% of non-diabetic cases, (p=0.002). It was observed that 21 out of 34 isolates produced a weakly positive biofilm, 8 were moderately positive, three were strongly positive, and two isolates were biofilm negative. Of the CoNS strains four of the 11 were resistance to four or more antibiotics.

CONCLUSION: Microorganisms that remained at the end of cataract surgery had the capacity to produce biofilm and had high antibiotic resistance. Appropriate preoperative disinfection is very important and adequate disinfection and suitable antibiotics should be kept in mind for avoiding endophthalmitis, especially for diabetic patients. Biofilm is one of the major factors affecting the virulence of bacteria, and further studies into prevention of biofilm formation are required in this area.}, } @article {pmid26760484, year = {2016}, author = {Garrido-Baserba, M and Asvapathanagul, P and McCarthy, GW and Gocke, TE and Olson, BH and Park, HD and Al-Omari, A and Murthy, S and Bott, CB and Wett, B and Smeraldi, JD and Shaw, AR and Rosso, D}, title = {Linking biofilm growth to fouling and aeration performance of fine-pore diffuser in activated sludge.}, journal = {Water research}, volume = {90}, number = {}, pages = {317-328}, doi = {10.1016/j.watres.2015.12.011}, pmid = {26760484}, issn = {1879-2448}, mesh = {*Biofilms ; Biofouling ; Ceramics/chemistry ; DNA, Bacterial/analysis ; Deoxyribonucleases/chemistry ; Diffusion ; Elastomers/chemistry ; Equipment Design ; Ethylenes/chemistry ; Microbial Consortia ; Microscopy, Confocal ; Oxygen/chemistry ; Pressure ; Sewage/chemistry ; Waste Disposal, Fluid/*methods ; Wastewater ; Water Microbiology ; Water Purification/*methods ; }, abstract = {Aeration is commonly identified as the largest contributor to process energy needs in the treatment of wastewater and therefore garners significant focus in reducing energy use. Fine-pore diffusers are the most common aeration system in municipal wastewater treatment. These diffusers are subject to fouling and scaling, resulting in loss in transfer efficiency as biofilms form and change material properties producing larger bubbles, hindering mass transfer and contributing to increased plant energy costs. This research establishes a direct correlation and apparent mechanistic link between biofilm DNA concentration and reduced aeration efficiency caused by biofilm fouling. Although the connection between biofilm growth and fouling has been implicit in discussions of diffuser fouling for many years, this research provides measured quantitative connection between the extent of biofouling and reduced diffuser efficiency. This was clearly established by studying systematically the deterioration of aeration diffusers efficiency during a 1.5 year period, concurrently with the microbiological study of the biofilm fouling in order to understand the major factors contributing to diffuser fouling. The six different diffuser technologies analyzed in this paper included four different materials which were ethylene-propylene-diene monomer (EPDM), polyurethane, silicone and ceramic. While all diffusers foul eventually, some novel materials exhibited fouling resistance. The material type played a major role in determining the biofilm characteristics (i.e., growth rate, composition, and microbial density) which directly affected the rate and intensity at what the diffusers were fouled, whereas diffuser geometry exerted little influence. Overall, a high correlation between the increase in biofilm DNA and the decrease in αF was evident (CV < 14.0 ± 2.0%). By linking bacterial growth with aeration efficiency, the research was able to show quantitatively the causal connection between bacterial fouling and energy wastage during aeration.}, } @article {pmid26759424, year = {2016}, author = {Fusconi, M and Petrozza, V and Schippa, S and de Vincentiis, M and Familiari, G and Pantanella, F and Cirenza, M and Iebba, V and Battaglione, E and Greco, A and Gallipoli, C and Campo, F and Gallo, A}, title = {Bacterial Biofilm in Salivary Gland Stones: Cause or Consequence?.}, journal = {Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery}, volume = {154}, number = {3}, pages = {449-453}, doi = {10.1177/0194599815622425}, pmid = {26759424}, issn = {1097-6817}, mesh = {*Biofilms ; DNA, Bacterial/*analysis ; Humans ; Microscopy, Electron, Scanning ; Real-Time Polymerase Chain Reaction ; Salivary Gland Calculi/*microbiology ; }, abstract = {OBJECTIVE: The pathogenesis of salivary calculi is not yet clear; however, 2 theories have been formulated: (1) "the classic theory," based on calcium microdeposits in serous and ductal acinous cells, successively discharged into the ducts; (2) "the retrograde theory," based on a retrograde migration of food, bacteria, and so on from the oral cavity to the salivary duct. The aim of the present study is to highlight the role of bacteria and biofilm in stone formation.

STUDY DESIGN: Case series without comparison.

SETTING: Laboratory of the Department of Anatomical Pathology.

SUBJECTS AND METHODS: Traditional optic microscopy and scanning electron microscopy were carried out on 15 salivary gland calculi that were collected from 12 patients. A qPCR (quantitative real-time polymerase chain reaction) assay was performed to highlight the presence of bacterial DNA on each stone.

RESULTS: Optic microscopy showed formations that-due to their size, shape, and Gram and Giemsa staining-seemed to be Gram-positive bacterial cells. PAS- (periodic acid-Schiff) and alcian-PAS-positive staining matrix was present around them. The ultrastructural observation of the material processed for scanning electron microscopy showed the presence of structures resembling bacterial cells in the middle of the stones, surrounded by soft, amorphous material. Results of qPCR showed the presence of bacterial DNA in the internal part of the tissue sample.

CONCLUSIONS: The presence of bacteria and/or bacterial products resembling biofilm in salivary gland stones supports the "retrograde theory." This evidence may support the hypothesis that biofilm could be the causative effect of lithiasic formations.}, } @article {pmid26759299, year = {2015}, author = {He, Z and Wang, Y and Huang, Z}, title = {[Effect of luxS overexpression on biofilm formation by Streptococcus mutans].}, journal = {Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology}, volume = {50}, number = {9}, pages = {554-560}, pmid = {26759299}, issn = {1002-0098}, mesh = {Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Carbon-Sulfur Lyases/genetics/*metabolism ; Microscopy, Confocal ; Plasmids/genetics ; Quorum Sensing/genetics ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans/*physiology ; Tetrazolium Salts ; Time Factors ; }, abstract = {OBJECTIVE: To evaluate the effect of quorum sensing luxS gene on biofilm formation through construction of a luxS overexpression strain by Streptococcus mutans (Sm).

METHODS: In order to construct pIB-luxS plasmid, the luxS gene fragment amplified by PCR was inserted into the shuttle plasmid pIB169 by corresponding double digests. The pIB-luxS plasmid was linearized electro-transformed into Sm cell and the overexpression strain was selected on chloramphenicol plate and testified by electrophoresis and western blot. The growth rate of both Sm wild type strain and its luxS overexpression strain were observed. Methyl thiazolyl tetrazolium (MTT) assay method was used to compare the biofilm formation quantification by both strains at different time points and containing different sucrose. The structures of the biofilms were observed by using confocal laser scanning microscopy, and biofilm-related gene expressions were investigated by real-time PCR. All experiments were performed in triplicate.

RESULTS: The luxS overexpression strain was successfully constructed and confirmed by electrophoresis and Western blotting. The planktonic growth mode of the wild-type and luxS overexpression strain showed no difference, but biofilm formed by Sm overexpression strain was 0.400 ± 0.009 and 0.609 ± 0.041 at 14 and 24 h, higher than the wild type strain biofilm at the same time point (0.352 ± 0.028 and 0.533 ± 0.014, respectively, P < 0.05). After adding 0.125% sucrose, biofilm formed by Sm overexpression strain raised to 1.041 ± 0.038, higher than that by the wild type strain (0.831 ± 0.020, P < 0.05). The biofilm formed by both strains were also increased with the sucrose concentration increase, but there was no difference between them. The overexpression strain aggregated into distinct clusters on structure, genes expression including gtfB, ftf, gbpB, relA, brpA, smu630, comDE, vicR were increased (6.10 ± 0.12, 3.34 ± 0.07, 8.75 ± 0.13, 2.96 ± 0.04, 5.20 ± 0.19, 2.20 ± 0.06, 2.32 ± 0.07 and 10.67 ± 0.57 fold) compared to the wild-type strain (P < 0.05).

CONCLUSIONS: Quorum sensing luxS gene can promote the biofilm formation of Sm.}, } @article {pmid26758935, year = {2016}, author = {Moen, B and Røssvoll, E and Måge, I and Møretrø, T and Langsrud, S}, title = {Microbiota formed on attached stainless steel coupons correlates with the natural biofilm of the sink surface in domestic kitchens.}, journal = {Canadian journal of microbiology}, volume = {62}, number = {2}, pages = {148-160}, doi = {10.1139/cjm-2015-0562}, pmid = {26758935}, issn = {1480-3275}, mesh = {Bacteria/classification/isolation & purification ; Bacterial Load ; *Biofilms ; High-Throughput Nucleotide Sequencing ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; *Stainless Steel ; }, abstract = {Stainless steel coupons are frequently used in biofilm studies in the laboratory, as this material is commonly used in the food industry. The coupons are attached to different surfaces to create a "natural" biofilm to be studied further in laboratory trials. However, little has been done to investigate how well the microbiota on such coupons represents the surrounding environment. The microbiota on sink wall surfaces and on new stainless steel coupons attached to the sink wall for 3 months in 8 domestic kitchen sinks was investigated by next-generation sequencing (MiSeq) of the 16S rRNA gene derived from DNA and RNA (cDNA), and by plating and identification of colonies. The mean number of colony-forming units was about 10-fold higher for coupons than sink surfaces, and more variation in bacterial counts between kitchens was seen on sink surfaces than coupons. The microbiota in the majority of biofilms was dominated by Moraxellaceae (genus Moraxella/Enhydrobacter) and Micrococcaceae (genus Kocuria). The results demonstrated that the variation in the microbiota was mainly due to differences between kitchens (38.2%), followed by the different nucleic acid template (DNA vs RNA) (10.8%), and that only 5.1% of the variation was a result of differences between coupons and sink surfaces. The microbiota variation between sink surfaces and coupons was smaller for samples based on their RNA than on their DNA. Overall, our results suggest that new stainless steel coupons are suited to model the dominating part of the natural microbiota of the surrounding environment and, furthermore, are suitable for different downstream studies.}, } @article {pmid26758707, year = {2016}, author = {Plotkin, BJ and Sigar, IM and Tiwari, V and Halkyard, S}, title = {Herpes Simplex Virus (HSV) Modulation of Staphylococcus aureus and Candida albicans Initiation of HeLa 299 Cell-Associated Biofilm.}, journal = {Current microbiology}, volume = {72}, number = {5}, pages = {529-537}, pmid = {26758707}, issn = {1432-0991}, mesh = {*Biofilms ; Candida albicans/growth & development/*physiology ; Candidiasis/*microbiology ; HeLa Cells ; Herpesvirus 1, Human/*physiology ; Humans ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/growth & development/*physiology ; }, abstract = {Although herpes simplex virus type-1 (HSV-1), and type-2 (HSV-2), Staphylococcus aureus and Candida albicans co-habit the oral and genital mucosa, their interaction is poorly understood. We determined the effect HSV has on bacterial and/or fungal adherence, the initial step in biofilm formation. HeLa229 cells were infected with HSV-1 (KOS) gL86 or HSV-2 (KOS) 333gJ (-) at a multiplicity of infection (MOI) of 50 and 10. S. aureus (ATCC 25923) and/or C. albicans (yeast forms or germ tube forms) were co-incubated for 30 min (37 °C; 5 % CO2; 5:1 organism: HeLa cell ratio; n = 16) with virus-infected HeLa cells or uninfected HeLa cell controls. Post-incubation, the monolayers were washed (3x; PBS), lysed (RIPA), and the lysate plated onto Fungisel and/or mannitol salts agar for standard colony count. The level of HeLa-associated S. aureus was significantly decreased (P < 0.05) for both HSV-1- and HSV-2-infected cells, as compared to virus-free HeLa cell controls (38 and 59 % of control, respectively). In contrast, HSV-1 and HSV-2 significantly (P < 0.05) enhanced HeLa cell association of C. albicans yeast forms and germ tube approximately two-fold, respectively. The effect of S. aureus on germ tube and yeast form adherence to HSV-1- and HSV-2-infected cells was specific for the Candida phenotype tested. Our study suggests that HSV, while antagonist towards S. aureus adherence enhances Candida adherence. Furthermore, the combination of the three pathogens results in S. aureus adherence that is either unaffected, or partially restored depending on both the herpes viral species and the fungal phenotype present.}, } @article {pmid26758696, year = {2016}, author = {Siciliano, A and De Rosa, S}, title = {An experimental model of COD abatement in MBBR based on biofilm growth dynamic and on substrates' removal kinetics.}, journal = {Environmental technology}, volume = {37}, number = {16}, pages = {2058-2071}, doi = {10.1080/09593330.2016.1140814}, pmid = {26758696}, issn = {1479-487X}, mesh = {Biofilms ; Biological Oxygen Demand Analysis/*methods ; *Bioreactors ; Kinetics ; *Models, Theoretical ; Waste Disposal, Fluid/*methods ; }, abstract = {In this study, the performance of a lab-scale Moving Bed Biofilm Reactor (MBBR) under different operating conditions was analysed. Moreover, the dependence of the reaction rates both from the concentration and biodegradability of substrates and from the biofilm surface density, by means of several batch kinetic tests, was investigated. The reactor controls exhibited an increasing COD (Chemical Oxygen Demand) removal, reaching maximum yields (close to 90%) for influent loadings of up to12.5 gCOD/m(2)d. From this value, the pilot plant performance decreased to yields of only about 55% for influent loadings greater than 16 gCOD/m(2)d. In response to the influent loading increase, the biofilm surface density exhibited a logistic growing trend until reaching a maximum amount of total attached solids of about 9.5 g/m(2). The kinetic test results indicated that the COD removal rates for rapidly biodegradable, rapidly hydrolysable and slowly biodegradable substrates were not affected by the organic matter concentrations. Instead, first-order kinetics were detected with respect to biofilm surface density. The experimental results permitted the formulation of a mathematical model to predict the MBBR organic matter removal efficiency. The validity of the model was successfully tested in the lab-scale plant.}, } @article {pmid26756546, year = {2016}, author = {Nishikawa, S and Shinzawa, N and Nakamura, K and Ishigaki, K and Abe, H and Horiguchi, Y}, title = {The bvg-repressed gene brtA, encoding biofilm-associated surface adhesin, is expressed during host infection by Bordetella bronchiseptica.}, journal = {Microbiology and immunology}, volume = {60}, number = {2}, pages = {93-105}, doi = {10.1111/1348-0421.12356}, pmid = {26756546}, issn = {1348-0421}, mesh = {Adhesins, Bacterial/biosynthesis/*genetics/metabolism ; Animals ; Bacterial Adhesion/genetics ; Bacterial Proteins/genetics/metabolism/*physiology ; *Biofilms ; Bordetella Infections/*microbiology/pathology ; Bordetella bronchiseptica/genetics/metabolism/*physiology ; Female ; *Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Rats ; Rats, Wistar ; Trachea/microbiology/pathology ; Transcription Factors/genetics/metabolism/*physiology ; Transcriptional Activation ; Up-Regulation ; Virulence Factors/genetics/metabolism/physiology ; }, abstract = {Bordetella species display phase modulation between Bvg(+) and Bvg(-) phases. Because expression of known virulence factors is up-regulated in the Bvg(+) phase, bacteria in this phase are considered competent for infection. However, the Bvg(-) phase is of negligible importance for infection. No studies have shown that bacterial factors specific to the Bvg(-) phase (bvg-repressed factors) are expressed in the course of Bordetella infection. In the present study, the gene brtA (Bordetella RTX-family Adhesin), which is a typical bvg-repressed gene but is expressed in B. bronchiseptica infecting hosts, was characterized. BrtA is composed of repeated pairs of the VCBS unit and dystroglycan-type cadherin-like unit, the von Willebrand Factor A domain, RTX motif and type I secretion target signal. It is herein demonstrated that BrtA is secreted by the type I secretion system and is essential for Ca(2+) -dependent bacteria-to-substrate adherence, followed by biofilm formation. Although the contribution of BrtA to bacterial colonization of the rat trachea currently remains unclear, this is the first study to present concrete evidence for the expression of a bvg-repressed gene during infection, which may provide a novel aspect for analyses of Bordetella pathogenesis.}, } @article {pmid26756211, year = {2016}, author = {Jennings, JA and Beenken, KE and Parker, AC and Smith, JK and Courtney, HS and Smeltzer, MS and Haggard, WO}, title = {Polymicrobial Biofilm Inhibition Effects of Acetate-Buffered Chitosan Sponge Delivery Device.}, journal = {Macromolecular bioscience}, volume = {16}, number = {4}, pages = {591-598}, doi = {10.1002/mabi.201500347}, pmid = {26756211}, issn = {1616-5195}, mesh = {Acetates/chemistry ; Amikacin/chemistry/pharmacology ; Animals ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects/growth & development ; Catheter-Related Infections/*drug therapy/microbiology ; Catheters/microbiology ; Chitosan/*chemistry ; Delayed-Action Preparations ; Disease Models, Animal ; Drug Compounding ; Drug Liberation ; Freeze Drying ; Humans ; Mice ; Polytetrafluoroethylene ; Pseudomonas aeruginosa/*drug effects/physiology ; Skin ; Staphylococcus aureus/*drug effects/physiology ; Vancomycin/chemistry/pharmacology ; }, abstract = {Polymicrobial biofilm-associated implant infections present a challenging clinical problem. Through modifications of lyophilized chitosan sponges, degradable drug delivery devices for antibiotic solution have been fabricated for prevention and treatment of contaminated musculoskeletal wounds. Elution of amikacin, vancomycin, or a combination of both follows a burst release pattern with vancomycin released above minimum inhibitory concentration for Staphylococcus aureus for 72 h and amikacin released above inhibitory concentrations for Pseudomonas aeruginosa for 3 h. Delivery of a vancomycin, amikacin, or a combination of both reduces biofilm formation on polytetrafluoroethylene catheters in an in vivo model of contamination. Release of dual antibiotics from sponges is more effective at preventing biofilm formation than single-loaded chitosan sponges. Treatment of pre-formed biofilm with high-dose antibiotic release from chitosan sponges shows minimal reduction after 48 h. These results demonstrate infection-preventive efficacy for antibiotic-loaded sponges, as well as the need for modifications in the development of advanced materials to enhance treatment efficacy in removing established biofilm.}, } @article {pmid26756120, year = {2016}, author = {Shen, Y and Huang, C and Monroy, GL and Janjaroen, D and Derlon, N and Lin, J and Espinosa-Marzal, R and Morgenroth, E and Boppart, SA and Ashbolt, NJ and Liu, WT and Nguyen, TH}, title = {Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure.}, journal = {Environmental science & technology}, volume = {50}, number = {4}, pages = {1779-1787}, pmid = {26756120}, issn = {1520-5851}, support = {R01 EB013723/EB/NIBIB NIH HHS/United States ; R01EB013723/EB/NIBIB NIH HHS/United States ; }, mesh = {Biofilms/*drug effects ; Biomass ; Chloramines/pharmacology ; Chlorine/pharmacology ; Disinfectants/*pharmacology ; Disinfection/methods ; Drinking Water/*microbiology ; Elastic Modulus ; Microscopy, Atomic Force ; Time Factors ; Tomography, Optical Coherence ; Water Purification/*methods ; }, abstract = {Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine- or free-chlorine-treated biofilms was 4 to 9 times higher than those before treatment. Meanwhile, the biofilm thickness decreased from 120 ± 8 μm to 93 ± 6-107 ± 11 μm. The increased surface stiffness and decreased biofilm thickness within the first month of disinfectant exposure was presumably due to the consumption of biomass. However, by the second to third month during disinfectant exposure, the biofilm mean stiffness showed a 2- to 4-fold decrease, and the biofilm thickness increased to 110 ± 7-129 ± 8 μm, suggesting that the biofilms adapted to disinfectant exposure. After three months of the disinfectant exposure process, the disinfected biofilms showed 2-5 times higher mean stiffness (as determined by AFM) and 6-13-fold higher ratios of protein over polysaccharide, as determined by differential staining and confocal laser scanning microscopy (CLSM), than the nondisinfected groundwater biofilms. However, the disinfected biofilms and nondisinfected biofilms showed statistically similar thicknesses (t test, p > 0.05), suggesting that long-term disinfection may not significantly remove net biomass. This study showed how biofilm mechanical and structural properties vary in response to a complex DWDS environment, which will contribute to further research on the risk assessment and control of biofilm-associated-pathogens in DWDS.}, } @article {pmid26755629, year = {2016}, author = {Rogers, A and Townsley, L and Gallego-Hernandez, AL and Beyhan, S and Kwuan, L and Yildiz, FH}, title = {The LonA Protease Regulates Biofilm Formation, Motility, Virulence, and the Type VI Secretion System in Vibrio cholerae.}, journal = {Journal of bacteriology}, volume = {198}, number = {6}, pages = {973-985}, pmid = {26755629}, issn = {1098-5530}, support = {R01AI102584/AI/NIAID NIH HHS/United States ; R01 AI102584/AI/NIAID NIH HHS/United States ; S10-RR20939/RR/NCRR NIH HHS/United States ; S10 RR020939/RR/NCRR NIH HHS/United States ; R01AI055987/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Biofilms/*growth & development ; Gastrointestinal Tract/microbiology ; Gene Deletion ; Gene Expression Profiling ; *Locomotion ; Mice ; Protease La/genetics/*metabolism ; Type VI Secretion Systems/*metabolism ; Vibrio cholerae/*enzymology/genetics/*physiology ; Virulence ; }, abstract = {UNLABELLED: The presence of the Lon protease in all three domains of life hints at its biological importance. The prokaryotic Lon protease is responsible not only for degrading abnormal proteins but also for carrying out the proteolytic regulation of specific protein targets. Posttranslational regulation by Lon is known to affect a variety of physiological traits in many bacteria, including biofilm formation, motility, and virulence. Here, we identify the regulatory roles of LonA in the human pathogen Vibrio cholerae. We determined that the absence of LonA adversely affects biofilm formation, increases swimming motility, and influences intracellular levels of cyclic diguanylate. Whole-genome expression analysis revealed that the message abundance of genes involved in biofilm formation was decreased but that the message abundances of those involved in virulence and the type VI secretion system were increased in a lonA mutant compared to the wild type. We further demonstrated that a lonA mutant displays an increase in type VI secretion system activity and is markedly defective in colonization of the infant mouse. These findings suggest that LonA plays a critical role in the environmental survival and virulence of V. cholerae.

IMPORTANCE: Bacteria utilize intracellular proteases to degrade damaged proteins and adapt to changing environments. The Lon protease has been shown to be important for environmental adaptation and plays a crucial role in regulating the motility, biofilm formation, and virulence of numerous plant and animal pathogens. We find that LonA of the human pathogen V. cholerae is in line with this trend, as the deletion of LonA leads to hypermotility and defects in both biofilm formation and colonization of the infant mouse. In addition, we show that LonA regulates levels of cyclic diguanylate and the type VI secretion system. Our observations add to the known regulatory repertoire of the Lon protease and the current understanding of V. cholerae physiology.}, } @article {pmid26755532, year = {2016}, author = {Cavalcanti, IM and Nobbs, AH and Ricomini-Filho, AP and Jenkinson, HF and Del Bel Cury, AA}, title = {Interkingdom cooperation between Candida albicans, Streptococcus oralis and Actinomyces oris modulates early biofilm development on denture material.}, journal = {Pathogens and disease}, volume = {74}, number = {3}, pages = {}, doi = {10.1093/femspd/ftw002}, pmid = {26755532}, issn = {2049-632X}, mesh = {Actinomyces/*growth & development ; Adult ; Biofilms/*growth & development ; Candida albicans/*growth & development ; Dentures/*microbiology ; Humans ; In Situ Hybridization, Fluorescence ; Microbial Consortia/physiology ; Microscopy, Confocal ; Saliva ; Stomatitis, Denture/microbiology ; Streptococcus oralis/*growth & development ; Symbiosis/*physiology ; }, abstract = {Candida-associated stomatitis affects up to 60% of denture wearers, and Candida albicans remains the most commonly isolated fungal species. The oral bacteria Actinomyces oris and Streptococcus oralis are abundant in early dental plaque. The aims of this study were to determine the effects of S. oralis and A. oris on the development of C. albicans biofilms on denture material. Resin discs were coated with saliva and at early (1.5 h) or later (24 h) stages of biofilm development, cell numbers of each species were determined. Spatial distribution of microorganisms was visualized by confocal scanning laser microscopy of biofilms labelled by differential fluorescence or by fluorescence in situ hybridization. Interkingdom interactions underpinning biofilm development were also evaluated planktonically utilizing fluorescence microscopy. Synergistic interactions between all three species occurred within biofilms and planktonically. Bacterial cells coaggregated with each other and adhered singly or in coaggregates to C. albicans hyphal filaments. Streptococcus oralis appeared to enhance hyphal filament production and C. albicans biovolume was increased 2-fold. Concomitantly, cell numbers of S. oralis and A. oris were enhanced by C. albicans. Thus, cooperative physical and metabolic processes occurring between these three microbial species intensify pathogenic plaque communities on denture surfaces.}, } @article {pmid26754179, year = {2016}, author = {Balić, M and Lucić, R and Mehadžić, K and Bago, I and Anić, I and Jakovljević, S and Plečko, V}, title = {The efficacy of photon-initiated photoacoustic streaming and sonic-activated irrigation combined with QMiX solution or sodium hypochlorite against intracanal E. faecalis biofilm.}, journal = {Lasers in medical science}, volume = {31}, number = {2}, pages = {335-342}, pmid = {26754179}, issn = {1435-604X}, mesh = {Biguanides/*pharmacology ; Biofilms/*drug effects/radiation effects ; Dental Pulp Cavity/*microbiology ; Drug Interactions ; Enterococcus faecalis/drug effects/*physiology/radiation effects ; Humans ; Lasers, Solid-State ; *Photons ; Polymers/*pharmacology ; Root Canal Irrigants/pharmacology ; Sodium Hypochlorite/*pharmacology ; Solutions ; *Ultrasonic Waves ; }, abstract = {The aim of the study was to assess the antibacterial efficacy of photon-initiated photoacoustic streaming (PIPS) using an Er:YAG laser and sonic-activated irrigation combined with QMiX irrigant or sodium hypochlorite against Enterococcus faecalis intracanal biofilm. Root canals of 91 human extracted single-canal teeth were instrumented, sterilized, contaminated with E. faecalis and incubated for 15 days. The infected teeth were then randomly distributed into six experimental groups: G1: PIPS/Er:YAG laser (wavelength 2940 nm, pulse energy 20 mJ, 15 Hz, pulse duration 50 μs, energy density 2.06 J/cm(2), 3 × 20 s) with the QMiX irrigant; G2: PIPS/Er:YAG laser-activated 2.5 % NaOCl; G3 sonic-activated irrigation (EndoActivator system) for 60 s with the QMiX irrigant; G4 sonic-activated irrigation for 60 s with 2.5 % NaOCl; G5 30-gauge needle irrigation with the QMiX irrigant; G6 30-gauge needle irrigation with 2.5 % NaOCl. The positive control group was rinsed with sterile saline solution. The root canals were sampled by flushing with saline solution at baseline and after the treatments, serially diluted and cultured. The number of bacteria in each canal was determined by plate count. The presence and the absence of E. faecalis in root canals were demonstrated by polymerase chain reaction (PCR), and the pattern of the bacteria colonization was visualized by scanning electron microscopy. There was significant reduction in the bacterial population for all groups (p < 0.001). The best antibacterial efficacy was recorded after sonic-activated irrigation with both NaOCl (99.999 %) and QMiX (99.999 %) and after PIPS with QMiX (99.999 %), which were more effective than conventional irrigation with NaOCl (99.998 %) and the PIPS with the NaOCl (99.966 %). Also, the PIPS with QMiX solution provided the highest number of sterile samples (five). There was no difference in the bacteria reduction between the active irrigation techniques, regardless of the irrigant used. Although the laser activation did not improve the antimicrobial action of the NaOCl nor QMiX, the fact that it generated the greatest number of sterile samples warrants further investigation.}, } @article {pmid26752879, year = {2015}, author = {Taneja, S and Kumar, P and Malhotra, K and Dhillon, J}, title = {Antimicrobial effect of an oxazolidinone, lantibiotic and calcium hydroxide against Enterococcus faecalis biofilm: An in vitro study.}, journal = {Indian journal of dentistry}, volume = {6}, number = {4}, pages = {190-194}, pmid = {26752879}, issn = {0975-962X}, abstract = {AIMS: The aim was to evaluate and compare the antimicrobial efficacy of an oxazolidinone (linezolid [LZ]), lantibiotic (nisin), and calcium hydroxide against Enterococcus faecalis biofilm formed on tooth substrate after 2 and 7 days.

METHODS: Single rooted human mandibular premolars were decoronated, biomechanically prepared, and vertically sectioned along the midsagittal plane to obtain a standardized tooth substrate. Standardized suspension of E. faecalis and tooth substrate was incubated for 3 weeks to allow growth of biofilm. At the end of 3 weeks, the grouping was done according to the medicament used - Group I - LZ, Group II - nisin, Group III - calcium hydroxide, Group IV - negative treatment. Disk of the medicaments used were prepared and placed upon Petri dishes along with bacterial emulsion on Mueller-Hinton agar. The zones of inhibition were checked after 2 and 7 days.

STATISTICAL ANALYSIS USED: The scores were statistically analyzed using Tukey honest significant difference test and one-way analysis of variance.

RESULTS: Zone of inhibition obtained with LZ was widest followed by nisin and calcium hydroxide after a period of 2 days (P < 0.001). The size of the zone of inhibition remain unchanged for LZ and nisin group after 7 days (P > 0.001) unlike calcium hydroxide group where the zone decreased (P < 0.001).

CONCLUSION: LZ showed maximum antimicrobial potential against E. faecalis biofilm followed by nisin and calcium hydroxide after 2 and 7 days. The antimicrobial effect of LZ and nisin was not affected with the lapse of time, but that of calcium hydroxide significantly decreased.}, } @article {pmid26752840, year = {2015}, author = {Mistry, KS and Sanghvi, Z and Parmar, G and Shah, S and Pushpalatha, K}, title = {Antibacterial efficacy of Azadirachta indica, Mimusops elengi and 2% CHX on multispecies dentinal biofilm.}, journal = {Journal of conservative dentistry : JCD}, volume = {18}, number = {6}, pages = {461-466}, pmid = {26752840}, issn = {0972-0707}, abstract = {AIMS: To check the antimicrobial activity of Azadirachta indica (Neem), Mimusops elengi (Bakul), and Chlorhexidine gluconate (CHX) on multispecies biofilm of common endodontic pathogens such as Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus and Candida albicans.

SETTINGS AND DESIGN: In vitro dentin disinfection model used to check the antimicrobial efficacy of herbal extracts.

MATERIALS AND METHODS: The in vitro dentin disinfection model was used to check the antimicrobial activity of the methanolic extracts of the medicinal plants along with Chlorhexidine gluconate. The polymicrobial biofilm was allowed to grow on extracted teeth sections for a period of 21 days. Remaining microbial load in the form of CFU/ml after the antimicrobial treatment was tabulated, and data were statistically analyzed using ANOVA and Bonferroni post-hoc tests.

STATISTICAL ANALYSIS USED: SPSS version 17, one-way ANOVA, Bonferroni post-hoc test.

RESULTS: Both the plant extracts showed considerable antimicrobial efficacy as compared to negative control. 2% CHX was the most effective antimicrobial agent having statistically significant difference against plant extracts and negative control (saline).

CONCLUSION: The methanolic extract of A. Indica, M. elengi, and Chlorhexidine Gluconate has considerable antimicrobial activity against polymicrobial dentinal biofilm of S. mutans, E. faecalis, S. aureus and C. albicans.}, } @article {pmid26749812, year = {2015}, author = {Brandelli, CL and Ribeiro, VB and Zimmer, KR and Barth, AL and Tasca, T and Macedo, AJ}, title = {Medicinal Plants Used by a Mbyá-Guarani Tribe Against Infections: Activity on KPC-Producing Isolates and Biofilm-Forming Bacteria.}, journal = {Natural product communications}, volume = {10}, number = {11}, pages = {1847-1852}, pmid = {26749812}, issn = {1934-578X}, mesh = {Bacterial Proteins/metabolism ; Biofilms/drug effects ; Brazil ; Humans ; Klebsiella pneumoniae/*drug effects/enzymology/physiology ; Medicine, Traditional ; Microbial Sensitivity Tests ; Plant Extracts/*pharmacology ; Plants, Medicinal/*chemistry ; Pseudomonas aeruginosa/*drug effects/physiology ; Staphylococcus epidermidis/*drug effects/physiology ; beta-Lactamases/metabolism ; }, abstract = {The traditional use of medicinal plants for treatment of infectious diseases by an indigenous Mbyá-Guarani tribe from South Brazil was assessed by evaluating the antibiotic and antibiofilm activities against relevant bacterial pathogens. Aqueous extracts from 10 medicinal plants were prepared according to indigenous Mbyá-Guarani traditional uses. To evaluate antibiotic (OD600) and antibiofilm (crystal violet method) activities, Pseudomonas aeruginosa ATCC 27853, Staphylococcus epidermidis ATCC 35984 and seven multi-drug resistant Klebsiella pneumoniae carbapenemase (KPC)-producing bacterial clinical isolates were challenged with the extracts. Furthermore, the susceptibility profile of KPC-producing bacteria and the ability of these isolates to form biofilm were evaluated. The plants Campomanesia xanthocarpa, Maytenus ilicifolia, Bidens pilosa and Verbena sp. showed the best activity against bacterial growth and biofilm formation. The majority of KPC-producing isolates, which showed strong ability to form biofilm and a multidrug resistance profile, was inhibited by more than 50% by some extracts. The Enterobacter cloacae (KPC 05) clinical isolate was the only one resistant to all extracts. This study confirms the importance of indigenous traditional medicinal knowledge and describes for the first time the ability of these plants to inhibit biofilm formation and/or bacterial growth of multi-drug resistant KPC-producing isolates.}, } @article {pmid26749227, year = {2016}, author = {Mai, B and Wang, X and Liu, Q and Leung, AW and Wang, X and Xu, C and Wang, P}, title = {The antibacterial effect of sinoporphyrin sodium photodynamic therapy on Staphylococcus aureus planktonic and biofilm cultures.}, journal = {Lasers in surgery and medicine}, volume = {48}, number = {4}, pages = {400-408}, doi = {10.1002/lsm.22468}, pmid = {26749227}, issn = {1096-9101}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects/growth & development ; Biomarkers/metabolism ; Colony Count, Microbial ; Microscopy, Electron, Scanning ; Photochemotherapy/*methods ; Photosensitizing Agents/*pharmacology ; Plankton/*drug effects/physiology ; Porphyrins/*pharmacology ; Reactive Oxygen Species/metabolism ; Staphylococcus aureus/*drug effects/physiology ; }, abstract = {BACKGROUND AND OBJECTIVES: Staphylococcus aureus (S. aureus) are important causes of nosocomial and medical-device-related infections. Photodynamic treatment (PDT) has been proposed as an alternative approach for the inactivation of bacteria. Sinoporphyrin sodium (DVDMS) is a newly identified photosensitizer and has high photo-sensitivity when used in PDT. This study aims to evaluate the antibacterial effect of DVDMS mediated PDT on S. aureus planktonic and biofilm cultures.

The uptake of DVDMS in S. aureus was evaluated according to photometry after alkali lysis. Then bacteria were incubated with DVDMS and exposed to light treatment. After PDT treatment, counting colony-forming units (CFU) was applied to estimate the bactericidal effect. Intracellular reactive oxygen species (ROS) production was detected by flow cytometry. Scanning electron microscope (SEM) was performed to assess the disruption of biofilm.

RESULTS: With the incubation time increased, the relative fluorescence intensity of DVDMS in bacteria increased and reached peak at 75 minutes. DVDMS alone did not produce significant toxicity compared with the untreated group, while, remarkable survival decrease was observed in PDT groups in a dose-dependent manner. More than 90% of the bacteria were effectively killed by the combined treatment of 2 µM DVDMS with 10 J/cm2 light irradiation, and 4-log reduction in CFU was observed after 5 µM DVDMS treatment followed by 100 J/cm2 light irradiation. Intracellular ROS level was significantly enhanced after PDT treatment. The disruption of biofilm was confirmed by SEM, suggesting DVDMS-PDT effectively damaged the biofilm.

CONCLUSION: These results indicate DVDMS-PDT presents significant bactericidal activity.}, } @article {pmid26748533, year = {2016}, author = {Silva, MJ and de Oliveira, DG and Marcillo, OO and Neppelenbroek, KH and Lara, VS and Porto, VC}, title = {Effect of denture-coating composite on Candida albicans biofilm and surface degradation after disinfection protocol.}, journal = {International dental journal}, volume = {66}, number = {2}, pages = {86-92}, pmid = {26748533}, issn = {1875-595X}, mesh = {Acrylates/chemistry ; Acrylic Resins/*chemistry ; *Biofilms ; Candida albicans/*physiology ; Coated Materials, Biocompatible/*chemistry ; Coloring Agents ; Dental Materials/*chemistry ; Dental Polishing/methods ; *Denture Bases ; Denture Cleansers/chemistry ; Disinfection/*methods ; Gentian Violet ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Random Allocation ; Resin Cements/chemistry ; Saliva, Artificial/chemistry ; Sodium Hypochlorite/chemistry ; Surface Properties ; Time Factors ; }, abstract = {INTRODUCTION: Denture stomatitis is the most common pathology affecting denture wearers and its main cause is colonisation of dentures with Candida albicans.

OBJECTIVE: This study investigated the effectiveness of two commercial composite surface sealants (Biscover(®) LV and Surface Coat(®)) to reduce C. albicans biofilm colonisation on denture resin, as well as their surface integrity after disinfection cycles with 1% sodium hypochlorite solution.

METHODS: Heat-cured acrylic resin specimens were manufactured (10 mm × 10 mm × 1 mm). The specimen surfaces were mechanically polished to simulate rough or smooth denture surfaces. Four surface-treatment groups were tested: smooth surfaces [0.3 μm of mean roughness (Ra)]; rough surfaces (3 μm of Ra); rough surfaces treated with Biscover(®) LV; and rough surfaces treated with Surface Coat(®). Specimens of each group were randomly divided to undergo immersion in distilled water or 1% sodium hypochlorite for 30 or 90 cycles each. Specimens of all groups in each immersion solution were tested using a crystal violet (CV) staining assay for biofilm quantification and by scanning electron microscopy for visual analyses of surface integrity and biofilm structure. CV assay data were analysed using one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison test (P < 0.05).

RESULTS: The effectiveness and surface integrity of Biscover(®) LV-treated surfaces were similar to those of smooth surfaces, whereas Surface Coat(®) -treated surfaces presented a similar performance to rough surfaces in all solutions and cycles.

CONCLUSION: These results suggest the possibility of clinical use of Biscover(®) LV for denture coating on surfaces in which mechanical polish is not indicated, such as the fitting surface.}, } @article {pmid26746720, year = {2016}, author = {Heller, D and Helmerhorst, EJ and Gower, AC and Siqueira, WL and Paster, BJ and Oppenheim, FG}, title = {Microbial Diversity in the Early In Vivo-Formed Dental Biofilm.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {6}, pages = {1881-1888}, pmid = {26746720}, issn = {1098-5336}, support = {97577//Canadian Institutes of Health Research/Canada ; U54-TR001012/TR/NCATS NIH HHS/United States ; R37 DE005672/DE/NIDCR NIH HHS/United States ; R01 DE007652/DE/NIDCR NIH HHS/United States ; U54 TR001012/TR/NCATS NIH HHS/United States ; DE05672/DE/NIDCR NIH HHS/United States ; R01 DE021565/DE/NIDCR NIH HHS/United States ; 113166//Canadian Institutes of Health Research/Canada ; AI087803/AI/NIAID NIH HHS/United States ; DE021565/DE/NIDCR NIH HHS/United States ; F31 DE005672/DE/NIDCR NIH HHS/United States ; AI101067/AI/NIAID NIH HHS/United States ; K02 AI101067/AI/NIAID NIH HHS/United States ; 106657//Canadian Institutes of Health Research/Canada ; R01 DE005672/DE/NIDCR NIH HHS/United States ; R01 AI087803/AI/NIAID NIH HHS/United States ; DE07652/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacteria/*classification/genetics/*isolation & purification ; *Biodiversity ; Biofilms/*growth & development ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Healthy Volunteers ; Humans ; Metagenomics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Tooth/*microbiology ; }, abstract = {Although the mature dental biofilm composition is well studied, there is very little information on the earliest phase of in vivo tooth colonization. Progress in dental biofilm collection methodologies and techniques of large-scale microbial identification have made new studies in this field of oral biology feasible. The aim of this study was to characterize the temporal changes and diversity of the cultivable and noncultivable microbes in the early dental biofilm. Samples of early dental biofilm were collected from 11 healthy subjects at 0, 2, 4, and 6 h after removal of plaque and pellicle from tooth surfaces. With the semiquantitative Human Oral Microbiome Identification Microarray (HOMIM) technique, which is based on 16S rRNA sequence hybridizations, plaque samples were analyzed with the currently available 407 HOMIM microbial probes. This led to the identification of at least 92 species, with streptococci being the most abundant bacteria across all time points in all subjects. High-frequency detection was also made with Haemophilus parainfluenzae, Gemella haemolysans, Slackia exigua, and Rothia species. Abundance changes over time were noted for Streptococcus anginosus and Streptococcus intermedius (P = 0.02), Streptococcus mitis bv. 2 (P = 0.0002), Streptococcus oralis (P = 0.0002), Streptococcus cluster I (P = 0.003), G. haemolysans (P = 0.0005), and Stenotrophomonas maltophilia (P = 0.02). Among the currently uncultivable microbiota, eight phylotypes were detected in the early stages of biofilm formation, one belonging to the candidate bacterial division TM7, which has attracted attention due to its potential association with periodontal disease.}, } @article {pmid26745983, year = {2016}, author = {Li, Y and Zhang, P and Cai, W and Rosenblatt, JS and Raad, II and Xu, D and Gu, T}, title = {Glyceryl trinitrate and caprylic acid for the mitigation of the Desulfovibrio vulgaris biofilm on C1018 carbon steel.}, journal = {World journal of microbiology & biotechnology}, volume = {32}, number = {2}, pages = {23}, pmid = {26745983}, issn = {1573-0972}, mesh = {Biofilms/*drug effects ; Caprylates/*pharmacology ; Carbon/*chemistry ; Corrosion ; Desulfovibrio vulgaris/*drug effects/metabolism/*physiology ; Disinfectants/pharmacology ; Drug Synergism ; Microscopy, Confocal ; Nitroglycerin/*pharmacology ; Oxidation-Reduction ; Steel/*chemistry ; }, abstract = {Microbiologically influenced corrosion (MIC), also known as biocorrosion, is caused by corrosive biofilms. MIC is a growing problem, especially in the oil and gas industry. Among various corrosive microbes, sulfate reducing bacteria (SRB) are often the leading culprit. Biofilm mitigation is the key to MIC mitigation. Biocide applications against biofilms promote resistance over time. Thus, it is imperative to develop new biodegradable and cost-effective biocides for large-scale field applications. Using the corrosive Desulfovibrio vulgaris (an SRB) biofilm as a model biofilm, this work demonstrated that a cocktail of glyceryl trinitrate (GTN) and caprylic acid (CA) was very effective for biofilm prevention and mitigation of established biofilms on C1018 carbon steel coupons. The most probable number sessile cell count data and confocal laser scanning microscope biofilm images proved that the biocide cocktail of 25 ppm (w/w) GTN + 0.1% (w/w) CA successfully prevented the D. vulgaris biofilm establishment on C1018 carbon steel coupons while 100 ppm GTN + 0.1% CA effectively mitigated pre-established D. vulgaris biofilms on C1018 carbon steel coupons. In both cases, the cocktails were able to reduce the sessile cell count from 10(6) cells/cm(2) to an undetectable level.}, } @article {pmid26745311, year = {2016}, author = {Joseph, R and Naugolny, A and Feldman, M and Herzog, IM and Fridman, M and Cohen, Y}, title = {Cationic Pillararenes Potently Inhibit Biofilm Formation without Affecting Bacterial Growth and Viability.}, journal = {Journal of the American Chemical Society}, volume = {138}, number = {3}, pages = {754-757}, doi = {10.1021/jacs.5b11834}, pmid = {26745311}, issn = {1520-5126}, mesh = {Antimicrobial Cationic Peptides/chemistry/*pharmacology ; Biofilms/*drug effects ; Cations/chemistry/pharmacology ; Cell Line ; Cell Proliferation/drug effects ; Dose-Response Relationship, Drug ; Erythrocytes ; Gram-Positive Bacteria/cytology/*drug effects/*growth & development ; Humans ; Microbial Viability/*drug effects ; Molecular Conformation ; Structure-Activity Relationship ; }, abstract = {It is estimated that up to 80% of bacterial infections are accompanied by biofilm formation. Since bacteria in biofilms are less susceptible to antibiotics than are bacteria in the planktonic state, biofilm-associated infections pose a major health threat, and there is a pressing need for antibiofilm agents. Here we report that water-soluble cationic pillararenes differing in the quaternary ammonium groups efficiently inhibited the formation of biofilms by clinically important Gram-positive pathogens. Biofilm inhibition did not result from antimicrobial activity; thus, the compounds should not inhibit growth of natural bacterial flora. Moreover, none of the cationic pillararenes caused detectable membrane damage to red blood cells or toxicity to human cells in culture. The results indicate that cationic pillararenes have potential for use in medical applications in which biofilm formation is a problem.}, } @article {pmid26743975, year = {2016}, author = {Kooltheat, N and Kamuthachad, L and Anthapanya, M and Samakchan, N and Sranujit, RP and Potup, P and Ferrante, A and Usuwanthim, K}, title = {Kaffir lime leaves extract inhibits biofilm formation by Streptococcus mutans.}, journal = {Nutrition (Burbank, Los Angeles County, Calif.)}, volume = {32}, number = {4}, pages = {486-490}, doi = {10.1016/j.nut.2015.10.010}, pmid = {26743975}, issn = {1873-1244}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics/metabolism ; Biofilms/*drug effects ; Citrus/*chemistry ; Dental Caries/drug therapy ; Down-Regulation ; Microbial Sensitivity Tests ; Phenols/analysis/pharmacology ; Plant Extracts/*pharmacology ; Plant Leaves/*chemistry ; RNA, Bacterial/genetics ; Streptococcus mutans/*drug effects ; Transcription Factor RelA/antagonists & inhibitors/genetics/metabolism ; }, abstract = {OBJECTIVES: Although kaffir lime has been reported to exhibit antioxidant and antileukemic activity, little is known about the antimicrobial effect of kaffir lime extract. Because Streptococcus mutans has been known to cause biofilm formation, it has been considered the most important causative pathogen of dental caries. Thus, the effective control of its effects on the oral biofilm is the key to the prevention of dental caries. The aims of the present study were to investigate the effect of kaffir lime leaves extract on biofilm formation and its antibacterial activity on S. mutans.

METHODS: We examined the effect of kaffir lime leaves extract on growth and biofilm formation of S. mutans. For the investigation we used a kaffir lime extract with high phenolic content. The minimum inhibitory concentration of the extract was determined by broth microdilution assay. The inhibitory effect of the test substances on biofilm formation was also investigated by biofilm formation assay and qRT-PCR of biofilm formation-associated genes.

RESULTS: Kaffir lime leaves extract inhibits the growth of S. mutans, corresponding to the activity of an antibiotic, ampicillin. Formation of biofilm by S. mutans was also inhibited by the extract. These results were confirmed by the down-regulation of genes associated with the biofilm formation.

CONCLUSIONS: The findings highlight the ability of kaffir lime leaves extract to inhibit S. mutans activity, which may be beneficial in the prevention of biofilm formation on dental surface, reducing dental plaque and decreasing the chance of dental carries.}, } @article {pmid26743211, year = {2016}, author = {Lee, S and Takahashi, Y and Oura, H and Suzuki-Minakuchi, C and Okada, K and Yamane, H and Nomura, N and Nojiri, H}, title = {Effects of carbazole-degradative plasmid pCAR1 on biofilm morphology in Pseudomonas putida KT2440.}, journal = {Environmental microbiology reports}, volume = {8}, number = {2}, pages = {261-271}, doi = {10.1111/1758-2229.12376}, pmid = {26743211}, issn = {1758-2229}, mesh = {Biofilms/*growth & development ; Biotransformation ; Carbazoles/*metabolism ; Gene Deletion ; Gene Expression Profiling ; Microscopy, Confocal ; *Plasmids ; Pseudomonas aeruginosa/genetics/physiology ; Pseudomonas fluorescens/genetics/physiology ; Pseudomonas putida/cytology/genetics/*physiology ; }, abstract = {Bacteria typically form biofilms under natural conditions. To elucidate the effect of the carriage of carbazole-degradative plasmid pCAR1 on biofilm formation by host bacteria, we compared the biofilm morphology, using confocal laser scanning microscopy, of three pCAR1-free and pCAR1-carrying Pseudomonas hosts: P. putida KT2440, P. aeruginosa PAO1 and P. fluorescens Pf0-1. Although pCAR1 did not significantly affect biofilm formation by PAO1 or Pf0-1, pCAR1-carrying KT2440 became filamentous and formed flat biofilms, whereas pCAR1-free KT2440 formed mushroom-like biofilms. pCAR1 contains three genes encoding nucleoid-associated proteins (NAPs), namely, Pmr, Pnd and Phu. The enhanced filamentous morphology was observed in two double mutants [KT2440(pCAR1ΔpmrΔpnd) and KT2440(pCAR1ΔpmrΔphu)], suggesting that these NAPs are involved in modulating the filamentous phenotype. Transcriptome analyses of the double mutants identified 32 candidate genes that may be involved in filamentation of KT2440. Overexpression of PP_2193 in KT2440 induced filamentation and overexpression of PP_0308 or PP_0309 in KT2440(pCAR1) enhanced filamentation of cells over time. This suggests that pCAR1 induces development of an abnormal filamentous morphology by KT2440 via a process involving overexpression of several genes, such as PP_2193. In addition, pCAR1-encoded NAPs partly suppress too much filamentation of KT2440(pCAR1) by repressing transcription of some genes, such as PP_0308 and PP_0309.}, } @article {pmid26742615, year = {2016}, author = {Ban, GH and Kang, DH}, title = {Effect of sanitizer combined with steam heating on the inactivation of foodborne pathogens in a biofilm on stainless steel.}, journal = {Food microbiology}, volume = {55}, number = {}, pages = {47-54}, doi = {10.1016/j.fm.2015.11.003}, pmid = {26742615}, issn = {1095-9998}, mesh = {*Biofilms ; Disinfectants/*pharmacology ; Disinfection/instrumentation/*methods ; Escherichia coli O157/drug effects/*growth & development/physiology ; Listeria monocytogenes/drug effects/*growth & development/physiology ; Microbial Viability ; Salmonella typhimurium/drug effects/*growth & development/physiology ; Sodium Hypochlorite/pharmacology ; Stainless Steel/*analysis ; Steam/analysis ; }, abstract = {The combined effect of chemical sanitizers including sodium hypochlorite, hydrogen peroxide, iodophor, and benzalkonium chloride with steam heating on the inactivation of biofilms formed by Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on stainless steel was investigated. Six day old biofilms, comprised of a mixture of three strains each of three foodborne pathogens, were produced on stainless steel coupons at 25 °C and treated with each sanitizer alone (for 5, 15, and 30 s), steam alone (for 5, 10, and 20 s), and the combination. There was a synergistic effect of sanitizer and steam on the viability of biofilm cells of the three pathogens as evidenced by plating counts and imaging. The combination treatment achieved an additional 0.01 to 2.78 log reduction compared to the sum of each individual treatment. The most effective combination for reducing levels of biofilm cells was the combination of steam and iodophor; steam for 20 s and merely 20 ppm iodophor for 30 s reduced cell numbers to below the detection limit (<1.48 log CFU/coupon). These results suggest that the combination treatment of sanitizer with steam can be applied to control foodborne pathogens biofilm cells in food processing facilities as a potential intervention.}, } @article {pmid26742560, year = {2016}, author = {Díaz De Rienzo, MA and Stevenson, PS and Marchant, R and Banat, IM}, title = {Pseudomonas aeruginosa biofilm disruption using microbial surfactants.}, journal = {Journal of applied microbiology}, volume = {120}, number = {4}, pages = {868-876}, doi = {10.1111/jam.13049}, pmid = {26742560}, issn = {1365-2672}, mesh = {Biofilms/*drug effects ; Glycolipids/*pharmacology ; Pseudomonas aeruginosa/*drug effects/physiology ; Sodium Dodecyl Sulfate/pharmacology ; Surface-Active Agents/*pharmacology ; }, abstract = {AIMS: To establish the ability of the rhamnolipids biosurfactants from Pseudomonas aeruginosa, in the presence and absence of caprylic acid and ascorbic acid, to disrupt bacterial biofilms, compared with the anionic alkyl sulphate surfactant Sodium dodecyl sulphate (SDS).

METHODS AND RESULTS: Pseudomonas aeruginosa ATCC 15442 biofilms were disrupted by rhamnolipids at concentrations between 0·5 and 0·4 g l(-1) and with SDS at 0·8 g l(-1) . The combination of rhamnolipids 0·4 g l(-1) and caprylic acid at 0·1 g l(-1) showed a remarkable effect on biofilm disruption and cell killing. After 30 min of treatment most of the biofilm was disrupted and cell viability was significantly reduced. Neither caprylic acid nor ascorbic acid has any effect on biofilm disruption at 0·1 g l(-1) . SDS is an effective antimicrobial agent; however, in the presence of caprylic acid its effect was neutralized.

CONCLUSIONS: The results show that rhamnolipids at low concentration in the presence of caprylic acid are promising molecules for inhibition/disruption of biofilms formed by Ps. aeruginosa ATCC 15442.

The disruption of biofilms has major significance in many industrial and domestic cleaning applications and in medical situations.}, } @article {pmid26741396, year = {2016}, author = {Han, Y and Hwang, G and Kim, D and Bradford, SA and Lee, B and Eom, I and Kim, PJ and Choi, SQ and Kim, H}, title = {Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating.}, journal = {Water research}, volume = {90}, number = {}, pages = {247-257}, doi = {10.1016/j.watres.2015.12.009}, pmid = {26741396}, issn = {1879-2448}, mesh = {*Biofilms ; Electrolytes ; Groundwater ; Hydrogen-Ion Concentration ; Ions ; Metal Nanoparticles/*chemistry ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Osmolar Concentration ; Polymers ; Porosity ; Pseudomonas putida ; Quartz/*chemistry ; Silicon Dioxide/chemistry ; Solubility ; Torque ; Water Pollutants, Chemical/isolation & purification ; Water Purification/*methods ; Zinc ; Zinc Oxide/*chemistry ; }, abstract = {The transport, retention, and long-term release of zinc oxide nanoparticle aggregates (denoted below as ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and the ionic strength (IS) was 0.1 or 10 mM NaCl, and the retention profiles were always hyper-exponential. Increasing the solution IS and biofilm coating produced enhanced retention of ZnO-NPs near the column inlet. The enhanced NPs retention at high IS was attributed to more favorable NP-silica and NP-NP interactions; this was consistent with the interaction energy calculations. Meanwhile, the greater NPs retention in the presence of biofilm was attributed to larger roughness heights which alter the mass transfer rate, the interaction energy profile, and lever arms associated with the torque balance; e.g., scanning electron and atomic force microscopy was used to determine roughness heights of 33.4 nm and 97.8 nm for bare sand and biofilm-coated sand, respectively. Interactions between NPs and extracellular polymeric substances may have also contributed to enhanced NP retention in biofilm-coated sand at low IS. The long-term release of retained ZnO-NPs was subsequently investigated by continuously injecting NP-free solution at pH 6, 9, or 10 and keeping the IS constant at 10 mM. The amount and rate of retained ZnO-NP removal was strongly dependent on the solution pH. Specifically, almost complete removal of retained ZnO-NPs was observed after 627 pore volumes when the solution pH was 6, whereas much less Zn was recovered when the eluting solution pH was buffered to pH = 9 and especially 10. This long-term removal was attributed to pH-dependent dissolution of retained ZnO-NPs because: (i) the solubility of ZnO-NPs increases with decreasing pH; and (ii) ZnO-NPs were not detected in the effluent. The presence of biofilm also decreased the initial rate and amount of dissolution and the subsequent transport of Zn(2+) due to the strong Zn(2+) re-adsorption to the biofilm. Our study indicates that dissolution will eventually lead to the complete removal of retained ZnO-NPs and the transport of toxic Zn(2+) ions in groundwater environments with pH ranges of 5-9.}, } @article {pmid26739155, year = {2016}, author = {Iakhiaeva, E and Howard, ST and Brown Elliott, BA and McNulty, S and Newman, KL and Falkinham, JO and Williams, M and Kwait, R and Lande, L and Vasireddy, R and Turenne, C and Wallace, RJ}, title = {Variable-Number Tandem-Repeat Analysis of Respiratory and Household Water Biofilm Isolates of "Mycobacterium avium subsp. hominissuis" with Establishment of a PCR Database.}, journal = {Journal of clinical microbiology}, volume = {54}, number = {4}, pages = {891-901}, pmid = {26739155}, issn = {1098-660X}, support = {T32 GM008169/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacterial Proteins/genetics ; *Biofilms ; Chaperonin 60/genetics ; Cluster Analysis ; DNA Transposable Elements ; DNA, Ribosomal Spacer/genetics ; Family Characteristics ; Genotype ; Humans ; Japan ; *Minisatellite Repeats ; Molecular Epidemiology/methods ; Molecular Typing/*methods ; Mycobacterium avium/*classification/genetics/*isolation & purification ; Phylogeography ; Polymerase Chain Reaction/methods ; Tuberculosis/*microbiology ; *Water Microbiology ; }, abstract = {"Mycobacterium aviumsubsp.hominissuis" is an important cause of pulmonary disease. It is acquired from environmental sources, but there is no methodology for large population studies. We evaluated the potential of variable-number tandem-repeat (VNTR) analysis. Clinical and household biofilmM. aviumisolates underwent molecular identification. Testing for IS901was done to separateM. aviumsubsp.aviumfromM. aviumsubsp.hominissuis VNTR types were defined using VNTR loci, and subtyping was performed using 3'hsp65and internal transcribed spacer (ITS) sequencing. Forty-nine VNTR types and eight subtypes ofM. aviumsubsp.hominissuis(IS901negative) were identified among 416 isolates ofM. aviumfrom 121 patients and 80 biofilm sites. Of those types, 67% were found only among patient isolates, 11% only among household water isolates, and 23% among both. Of 13 VNTR types that included ≥4 patients, the majority (61.5%) represented geographic clustering (same city). Most VNTR types with multiple patients belonged to the same 3'hsp65sequence code (sequevar). A total of 44 isolates belonging to fourM. aviumsubsp.hominissuisVNTR types (8%), including three with the rare Mav-F ITS sequence and 0/8 subspecies, produced amplicons with IS901PCR primers. By sequencing, all 44 amplicons were not IS901but ISMav6, which was recently observed in Japan but had not been previously described among U.S. isolates. VNTR analysis ofM. aviumsubsp.hominissuisisolates is easier and faster than pulsed-field gel electrophoresis. Seven VNTR loci separated 417 isolates into 49 types. No isolates ofM. aviumsubsp.aviumwere identified. The distributions of the VNTR copy numbers, the allelic diversity, and the low prevalence of ISMav6 differed from the findings for respiratory isolates reported from Japan.}, } @article {pmid26735879, year = {2016}, author = {He, Y and Wang, Y and Song, X}, title = {High-effective denitrification of low C/N wastewater by combined constructed wetland and biofilm-electrode reactor (CW-BER).}, journal = {Bioresource technology}, volume = {203}, number = {}, pages = {245-251}, doi = {10.1016/j.biortech.2015.12.060}, pmid = {26735879}, issn = {1873-2976}, mesh = {Autotrophic Processes ; Bacteria ; Biofilms ; Bioreactors ; Carbon/*analysis/chemistry ; *Denitrification ; Electrodes ; Heterotrophic Processes ; Nitrogen/*analysis/chemistry ; Wastewater/*chemistry ; Water Purification/methods ; *Wetlands ; }, abstract = {The low denitrification effect on constructed wetlands (CWs) treating low carbon to nitrogen ratio (C/N) wastewater was a problem. In this study, a novel coupled system by installing CW and biofilm-electrode reactor (CW-BER) was developed. In this system, the heterotrophic and autotrophic denitrifying bacteria all played their roles in denitrification process. The system was investigated systematically with simulated wastewater at different C/Ns, electric current intensities (I), hydraulic retention times (HRTs), and pH. Results showed that the optimum running conditions were C/N=0.75-1, I=15 mA, HRT=12 h, and pH=7.5. The highest removal efficiency of NO3-N and TN at the best conditions was respectively 63.03% and 98.11% for CW-BER. Also, the TN and NO3-N enhancive removal efficiency of CW-BER was 23.26% and 24.20%, respectively. No residual organic carbon source was detected in final effluent at the best parameters.}, } @article {pmid26735875, year = {2016}, author = {Yang, Y and Ye, D and Liao, Q and Zhang, P and Zhu, X and Li, J and Fu, Q}, title = {Enhanced biofilm distribution and cell performance of microfluidic microbial fuel cells with multiple anolyte inlets.}, journal = {Biosensors & bioelectronics}, volume = {79}, number = {}, pages = {406-410}, doi = {10.1016/j.bios.2015.12.067}, pmid = {26735875}, issn = {1873-4235}, mesh = {*Bioelectric Energy Sources ; Biofilms/*growth & development ; *Biosensing Techniques ; Electrodes ; Microfluidics/methods ; }, abstract = {A laminar-flow controlled microfluidic microbial fuel cell (MMFC) is considered as a promising approach to be a bio-electrochemical system (BES). But poor bacterial colonization and low power generation are two severe bottlenecks to restrict its development. In this study, we reported a MMFC with multiple anolyte inlets (MMFC-MI) to enhance the biofilm formation and promote the power density of MMFCs. Voltage profiles during the inoculation process demonstrated MMFC-MI had a faster start-up process than the conventional microfluidic microbial fuel cell with one inlet (MMFC-OI). Meanwhile, benefited from the periodical replenishment of boundary layer near the electrode, a more densely-packed bacterial aggregation was observed along the flow direction and also the substantially low internal resistance for MMFC-MI. Most importantly, the output power density of MMFC-MI was the highest value among the reported µl-scale MFCs to our best knowledge. The presented MMFC-MI appears promising for bio-chip technology and extends the scope of microfluidic energy.}, } @article {pmid26733973, year = {2015}, author = {Lei, L and Yang, Y and Mao, M and Li, H and Li, M and Yang, Y and Yin, J and Hu, T}, title = {Modulation of Biofilm Exopolysaccharides by the Streptococcus mutans vicX Gene.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1432}, pmid = {26733973}, issn = {1664-302X}, abstract = {The cariogenic pathogen Streptococcus mutans effectively utilizes dietary sucrose for the synthesis of exopolysaccharide, which act as a scaffold for its biofilm, thus contributing to its pathogenicity, environmental stress tolerance, and antimicrobial resistance. The two-component system VicRK of S. mutans regulates a group of virulence genes that are associated with biofilm matrix synthesis. Knockout of vicX affects biofilm formation, oxidative stress tolerance, and transformation of S. mutans. However, little is known regarding the vicX-modulated structural characteristics of the exopolysaccharides underlying the biofilm formation and the phenotypes of the vicX mutants. Here, we identified the role of vicX in the structural characteristics of the exopolysaccharide matrix and biofilm physiology. The vicX mutant (SmuvicX) biofilms seemingly exhibited "desertification" with architecturally impaired exopolysaccharide-enmeshed cell clusters, compared with the UA159 strain (S. mutans wild type strain). Concomitantly, SmuvicX showed a decrease in water-insoluble glucan (WIG) synthesis and in WIG/water-soluble glucan (WSG) ratio. Gel permeation chromatography (GPC) showed that the WIG isolated from the SmuvicX biofilms had a much lower molecular weight compared with the UA159 strain indicating differences in polysaccharide chain lengths. A monosaccharide composition analysis demonstrated the importance of the vicX gene in the glucose metabolism. We performed metabolite profiling via (1)H nuclear magnetic resonance spectroscopy, which showed that several chemical shifts were absent in both WSG and WIG of SmuvicX biofilms compared with the UA159 strain. Thus, the modulation of structural characteristics of exopolysaccharide by vicX provides new insights into the interaction between the exopolysaccharide structure, gene functions, and cariogenicity. Our results suggest that vicX gene modulates the structural characteristics of exopolysaccharide associated with cariogenicity, which may be explored as a potential target that contributes to dental caries management. Furthermore, the methods used to purify the EPS of S. mutans biofilms and to analyze multiple aspects of its structure (GPC, gas chromatography-mass spectrometry, and (1)H nuclear magnetic resonance spectroscopy) may be useful approaches to determine the roles of other virulence genes for dental caries prevention.}, } @article {pmid26733972, year = {2015}, author = {Zetzmann, M and Okshevsky, M and Endres, J and Sedlag, A and Caccia, N and Auchter, M and Waidmann, MS and Desvaux, M and Meyer, RL and Riedel, CU}, title = {DNase-Sensitive and -Resistant Modes of Biofilm Formation by Listeria monocytogenes.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1428}, pmid = {26733972}, issn = {1664-302X}, abstract = {Listeria monocytogenes is able to form biofilms on various surfaces and this ability is thought to contribute to persistence in the environment and on contact surfaces in the food industry. Extracellular DNA (eDNA) is a component of the biofilm matrix of many bacterial species and was shown to play a role in biofilm establishment of L. monocytogenes. In the present study, the effect of DNaseI treatment on biofilm formation of L. monocytogenes EGD-e was investigated under static and dynamic conditions in normal or diluted complex medium at different temperatures. Biofilm formation was quantified by crystal violet staining or visualized by confocal laser scanning microscopy. Biomass of surface-attached L. monocytogenes varies depending on temperature and dilution of media. Interestingly, L. monocytogenes EGD-e forms DNase-sensitive biofilms in diluted medium whereas in full strength medium DNaseI treatment had no effect. In line with these observations, eDNA is present in the matrix of biofilms grown in diluted but not full strength medium and supernatants of biofilms grown in diluted medium contain chromosomal DNA. The DNase-sensitive phenotype could be clearly linked to reduced ionic strength in the environment since dilution of medium in PBS or saline abolished DNase sensitivity. Several other but not all species of the genus Listeria display DNase-sensitive and -resistant modes of biofilm formation. These results indicate that L. monocytogenes biofilms are DNase-sensitive especially at low ionic strength, which might favor bacterial lysis and release of chromosomal DNA. Since low nutrient concentrations with increased osmotic pressure are conditions frequently found in food processing environments, DNaseI treatment represents an option to prevent or remove Listeria biofilms in industrial settings.}, } @article {pmid26733970, year = {2015}, author = {Kwiatek, A and Mrozek, A and Bacal, P and Piekarowicz, A and Adamczyk-Popławska, M}, title = {Type III Methyltransferase M.NgoAX from Neisseria gonorrhoeae FA1090 Regulates Biofilm Formation and Interactions with Human Cells.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1426}, pmid = {26733970}, issn = {1664-302X}, abstract = {Neisseria gonorrhoeae is the etiological factor of the sexually transmitted gonorrhea disease that may lead, under specific conditions, to systemic infections. The gonococcal genome encodes many restriction modification (RM) systems, which main biological role is to defend the pathogen from potentially harmful foreign DNA. However, RM systems seem also to be involved in several other functions. In this study, we examined the effect of inactivation the N. gonorrhoeae FA1090 ngoAXmod gene encoding M.NgoAX methyltransferase on the global gene expression, biofilm formation, interactions with human epithelial host cells and overall bacterial growth. Expression microarrays showed at least a twofold deregulation of a total of 121 genes in the NgoAX knock-out mutant compared to the wild-type (wt) strain under standard grow conditions. Genes with changed expression levels encoded mostly proteins involved in cell metabolism, DNA replication and repair or regulating cellular processes and signaling (such as cell wall/envelop biogenesis). As determined by the assay with crystal violet, the NgoAX knock-out strain formed a slightly larger biofilm biomass per cell than the wt strain. Live biofilm observations showed that the biofilm formed by the gonococcal ngoAXmod gene mutant is more relaxed, dispersed and thicker than the one formed by the wt strain. This more relaxed feature of the biofilm, in respect to adhesion and bacterial interactions, can be involved in pathogenesis. Moreover, the overall adhesion of mutant bacterial cells to human cells was lower than adhesion of the wt gonococci [adhesion index = 0.672 (±0.2) and 2.15 (±1.53), respectively]; yet, a higher number of mutant than wt bacteria were found inside the Hec-1-B epithelial cells [invasion index = 3.38 (±0.93) × 10(5) for mutant and 4.67 (±3.09) × 10(4) for the wt strain]. These results indicate that NgoAX knock-out cells have lower ability to attach to human cells, but more easily penetrate inside the host cells. All these data suggest that the NgoAX methyltransferase, may be implicated in N. gonorrhoeae pathogenicity, involving regulation of biofilm formation, adhesion to host cells and epithelial cell invasion.}, } @article {pmid26733944, year = {2015}, author = {Grande, R and Di Marcantonio, MC and Robuffo, I and Pompilio, A and Celia, C and Di Marzio, L and Paolino, D and Codagnone, M and Muraro, R and Stoodley, P and Hall-Stoodley, L and Mincione, G}, title = {Helicobacter pylori ATCC 43629/NCTC 11639 Outer Membrane Vesicles (OMVs) from Biofilm and Planktonic Phase Associated with Extracellular DNA (eDNA).}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1369}, pmid = {26733944}, issn = {1664-302X}, abstract = {Helicobacter pylori persistence is associated with its capacity to develop biofilms as a response to changing environmental conditions and stress. Extracellular DNA (eDNA) is a component of H. pylori biofilm matrix but the lack of DNase I activity supports the hypothesis that eDNA might be protected by other extracellular polymeric substances (EPS) and/or Outer Membrane Vesicles (OMVs), which bleb from the bacteria surface during growth. The aim of the present study was to both identify the eDNA presence on OMVs segregated from H. pylori ATCC 43629/NCTC 11639 biofilm (bOMVs) and its planktonic phase (pOMVs) and to characterize the physical-chemical properties of the OMVs. The presence of eDNA in bOMVs and pOMVs was initially carried out using DNase I-gold complex labeling and Transmission Electron Microscope analysis (TEM). bOMVs and pOMVs were further isolated and physical-chemical characterization carried out using dynamic light scattering (DLS) analysis. eDNA associated with OMVs was detected and quantified using a PicoGreen spectrophotometer assay, while its extraction was performed with a DNA Kit. TEM images showed that eDNA was mainly associated with the OMV membrane surfaces; while PicoGreen staining showed a four-fold increase of dsDNA in bOMVs compared with pOMVs. The eDNA extracted from OMVs was visualized using gel electrophoresis. DLS analysis indicated that both planktonic and biofilm H. pylori phenotypes generated vesicles, with a broad distribution of sizes on the nanometer scale. The DLS aggregation assay suggested that eDNA may play a role in the aggregation of OMVs, in the biofilm phenotype. Moreover, the eDNA associated with vesicle membrane may impede DNase I activity on H. pylori biofilms. These results suggest that OMVs derived from the H. pylori biofilm phenotype may play a structural role by preventing eDNA degradation by nucleases, providing a bridging function between eDNA strands on OMV surfaces and promoting aggregation.}, } @article {pmid26731743, year = {2016}, author = {Fernández, CE and Tenuta, LM and Cury, JA}, title = {Validation of a Cariogenic Biofilm Model to Evaluate the Effect of Fluoride on Enamel and Root Dentine Demineralization.}, journal = {PloS one}, volume = {11}, number = {1}, pages = {e0146478}, pmid = {26731743}, issn = {1932-6203}, mesh = {Animals ; Biofilms/drug effects ; Cattle ; Dental Caries/complications/microbiology ; Dental Enamel/*drug effects/microbiology ; Dentin/*drug effects/microbiology ; Models, Biological ; Sodium Fluoride/*pharmacology ; Streptococcus mutans/drug effects ; Tooth/*drug effects/microbiology ; Tooth Demineralization/etiology/microbiology ; }, abstract = {Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8×/day to 10% sucrose and treated 2×/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2×/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (%SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and %SHL decreased at increasing fluoride concentrations (p < 0.05). Fluoride in the biofilm formed on dentine and fluoride uptake by dentine were higher than those for enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.}, } @article {pmid26731090, year = {2016}, author = {Fennelly, KP and Ojano-Dirain, C and Yang, Q and Liu, L and Lu, L and Progulske-Fox, A and Wang, GP and Antonelli, P and Schultz, G}, title = {Biofilm Formation by Mycobacterium abscessus in a Lung Cavity.}, journal = {American journal of respiratory and critical care medicine}, volume = {193}, number = {6}, pages = {692-693}, doi = {10.1164/rccm.201508-1586IM}, pmid = {26731090}, issn = {1535-4970}, mesh = {Biofilms/*growth & development ; Humans ; Male ; Middle Aged ; Mycobacterium Infections, Nontuberculous/*complications ; Nontuberculous Mycobacteria/*physiology ; Pulmonary Disease, Chronic Obstructive/*complications ; }, } @article {pmid26730967, year = {2016}, author = {Duyck, J and Vandamme, K and Krausch-Hofmann, S and Boon, L and De Keersmaecker, K and Jalon, E and Teughels, W}, title = {Impact of Denture Cleaning Method and Overnight Storage Condition on Denture Biofilm Mass and Composition: A Cross-Over Randomized Clinical Trial.}, journal = {PloS one}, volume = {11}, number = {1}, pages = {e0145837}, pmid = {26730967}, issn = {1932-6203}, mesh = {Bacteria/isolation & purification ; Bacterial Load ; Bacterial Physiological Phenomena ; *Biofilms/drug effects ; Candida albicans/isolation & purification/physiology ; Cross-Over Studies ; Denture Cleansers/metabolism ; Dentures/*microbiology ; Humans ; *Oral Hygiene/methods ; Toothbrushing/methods ; Ultrasonics/methods ; }, abstract = {BACKGROUND: Appropriate oral hygiene is required to maintain oral health in denture wearers. This study aims to compare the role of denture cleaning methods in combination with overnight storage conditions on biofilm mass and composition on acrylic removable dentures.

METHODS: In a cross-over randomized controlled trial in 13 older people, 4 conditions with 2 different mechanical cleaning methods and 2 overnight storage conditions were considered: (i) brushing and immersion in water without a cleansing tablet, (ii) brushing and immersion in water with a cleansing tablet, (iii) ultrasonic cleaning and immersion in water without a cleansing tablet, and (iv) ultrasonic cleaning and immersion in water with a cleansing tablet. Each test condition was performed for 5 consecutive days, preceded by a 2-days wash-out period. Biofilm samples were taken at baseline (control) and at the end of each test period from a standardized region. Total and individual levels of selected oral bacteria (n = 20), and of Candida albicans were identified using the Polymerase Chain Reaction (PCR) technique. Denture biofilm coverage was scored using an analogue denture plaque score. Paired t-tests and Wilcoxon-signed rank tests were used to compare the test conditions. The level of significance was set at α< 5%.

RESULTS: Overnight denture storage in water with a cleansing tablet significantly reduced the total bacterial count (p<0.01). The difference in total bacterial level between the two mechanical cleaning methods was not statistically significant. No significant effect was observed on the amount of Candida albicans nor on the analogue plaque scores.

CONCLUSIONS: The use of cleansing tablets during overnight denture storage in addition to mechanical denture cleaning did not affect Candida albicans count, but reduced the total bacterial count on acrylic removable dentures compared to overnight storage in water. This effect was more pronounced when combined with ultrasonic cleaning compared to brushing.

TRIAL REGISTRATION: ClinicalTrials.gov NCT02454413.}, } @article {pmid26730335, year = {2015}, author = {Shokouhfard, M and Kermanshahi, RK and Shahandashti, RV and Feizabadi, MM and Teimourian, S}, title = {The inhibitory effect of a Lactobacillus acidophilus derived biosurfactant on biofilm producer Serratia marcescens.}, journal = {Iranian journal of basic medical sciences}, volume = {18}, number = {10}, pages = {1001-1007}, pmid = {26730335}, issn = {2008-3866}, abstract = {OBJECTIVES: Serratia marcescens is one of the nosocomial pathogen with the ability to form biofilm which is an important feature in the pathogenesis of S. marcescens. The aim of this study was to determine the anti-adhesive properties of a biosurfactant isolated from Lactobacillus acidophilus ATCC 4356, on S. marcescens strains.

MATERIALS AND METHODS: Lactobacillus acidophilus ATCC 4356 was selected as a probiotic strain for biosurfactant production. Anti-adhesive activities was determined by pre-coating and co- incubating methods in 96-well culture plates.

RESULTS: The FTIR analysis of derived biosurfactant revealed the composition as protein component. Due to the release of such biosurfactants, L. acidophilus was able to interfere with the adhesion and biofilm formation of the S. marcescens strains. In co-incubation method, this biosurfactant in 2.5 mg/ml concentration showed anti-adhesive activity against all tested strains of S. marcescens (P<0.05).

CONCLUSION: Our results show that the anti-adhesive properties of L. acidophilus biosurfactant has the potential to be used against microorganisms responsible for infections in the urinary, vaginal and gastrointestinal tracts, as well as skin, making it a suitable alternative to conventional antibiotics.}, } @article {pmid26729873, year = {2016}, author = {Hendricks, MR and Lashua, LP and Fischer, DK and Flitter, BA and Eichinger, KM and Durbin, JE and Sarkar, SN and Coyne, CB and Empey, KM and Bomberger, JM}, title = {Respiratory syncytial virus infection enhances Pseudomonas aeruginosa biofilm growth through dysregulation of nutritional immunity.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {6}, pages = {1642-1647}, pmid = {26729873}, issn = {1091-6490}, support = {R01 HL123771/HL/NHLBI NIH HHS/United States ; P30 DK072506/DK/NIDDK NIH HHS/United States ; T32 AI007638/AI/NIAID NIH HHS/United States ; R00HL098342/HL/NHLBI NIH HHS/United States ; T32 AI060525/AI/NIAID NIH HHS/United States ; P30DK072506/DK/NIDDK NIH HHS/United States ; R03 HD080874/HD/NICHD NIH HHS/United States ; T32AI060525/AI/NIAID NIH HHS/United States ; R00 HL098342/HL/NHLBI NIH HHS/United States ; R01HL123771/HL/NHLBI NIH HHS/United States ; }, mesh = {Animals ; Antiviral Agents/pharmacology ; Biofilms/*growth & development ; Bronchi/pathology ; Bronchoalveolar Lavage Fluid ; Cystic Fibrosis/microbiology/pathology ; Epithelial Cells/drug effects/microbiology/virology ; Homeostasis/drug effects ; Humans ; *Immunity ; Interferon-beta/pharmacology ; Iron/pharmacology ; Mice ; Microbial Interactions/drug effects ; Models, Biological ; *Nutritional Physiological Phenomena ; Pseudomonas aeruginosa/drug effects/*physiology ; Respiratory Syncytial Virus Infections/*pathology ; Respiratory Syncytial Viruses/drug effects/*physiology ; Signal Transduction/drug effects ; Transferrin/metabolism ; }, abstract = {Clinical observations link respiratory virus infection and Pseudomonas aeruginosa colonization in chronic lung disease, including cystic fibrosis (CF) and chronic obstructive pulmonary disease. The development of P. aeruginosa into highly antibiotic-resistant biofilm communities promotes airway colonization and accounts for disease progression in patients. Although clinical studies show a strong correlation between CF patients' acquisition of chronic P. aeruginosa infections and respiratory virus infection, little is known about the mechanism by which chronic P. aeruginosa infections are initiated in the host. Using a coculture model to study the formation of bacterial biofilm formation associated with the airway epithelium, we show that respiratory viral infections and the induction of antiviral interferons promote robust secondary P. aeruginosa biofilm formation. We report that the induction of antiviral IFN signaling in response to respiratory syncytial virus (RSV) infection induces bacterial biofilm formation through a mechanism of dysregulated iron homeostasis of the airway epithelium. Moreover, increased apical release of the host iron-binding protein transferrin during RSV infection promotes P. aeruginosa biofilm development in vitro and in vivo. Thus, nutritional immunity pathways that are disrupted during respiratory viral infection create an environment that favors secondary bacterial infection and may provide previously unidentified targets to combat bacterial biofilm formation.}, } @article {pmid26729712, year = {2016}, author = {Kita, D and Shibata, S and Kikuchi, Y and Kokubu, E and Nakayama, K and Saito, A and Ishihara, K}, title = {Involvement of the Type IX Secretion System in Capnocytophaga ochracea Gliding Motility and Biofilm Formation.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {6}, pages = {1756-1766}, pmid = {26729712}, issn = {1098-5336}, mesh = {Bacterial Proteins/genetics/metabolism ; Bacterial Secretion Systems/genetics/*metabolism ; Biofilms/*growth & development ; Capnocytophaga/genetics/*physiology ; Gene Knockout Techniques ; *Locomotion ; }, abstract = {Capnocytophaga ochracea is a Gram-negative, rod-shaped bacterium that demonstrates gliding motility when cultured on solid agar surfaces. C. ochracea possesses the ability to form biofilms; however, factors involved in biofilm formation by this bacterium are unclear. A type IX secretion system (T9SS) in Flavobacterium johnsoniae was shown to be involved in the transport of proteins (e.g., several adhesins) to the cell surface. Genes orthologous to those encoding T9SS proteins in F. johnsoniae have been identified in the genome of C. ochracea; therefore, the T9SS may be involved in biofilm formation by C. ochracea. Here we constructed three ortholog-deficient C. ochracea mutants lacking sprB (which encodes a gliding motility adhesin) or gldK or sprT (which encode T9SS proteins in F. johnsoniae). Gliding motility was lost in each mutant, suggesting that, in C. ochracea, the proteins encoded by sprB, gldK, and sprT are necessary for gliding motility, and SprB is transported to the cell surface by the T9SS. For the ΔgldK, ΔsprT, and ΔsprB strains, the amounts of crystal violet-associated biofilm, relative to wild-type values, were 49%, 34%, and 65%, respectively, at 48 h. Confocal laser scanning and scanning electron microscopy revealed that the biofilms formed by wild-type C. ochracea were denser and bacterial cells were closer together than in those formed by the mutant strains. Together, these results indicate that proteins exported by the T9SS are key elements of the gliding motility and biofilm formation of C. ochracea.}, } @article {pmid26729086, year = {2015}, author = {Rendeková, K and Fialová, S and Jánošová, L and Mučaji, P and Slobodníková, L}, title = {The Activity of Cotinus coggygria Scop. Leaves on Staphylococcus aureus Strains in Planktonic and Biofilm Growth Forms.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {1}, pages = {E50}, pmid = {26729086}, issn = {1420-3049}, mesh = {Anacardiaceae/*chemistry ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/drug effects ; Methanol/chemistry/isolation & purification/*pharmacology ; Microbial Sensitivity Tests ; Plankton/drug effects ; Plant Extracts/chemistry/isolation & purification/pharmacology ; Plant Leaves/*chemistry ; Staphylococcus aureus/*drug effects ; Tandem Mass Spectrometry ; }, abstract = {The purpose of this study was to detect the effectiveness of Cotinus coggygria Scop. leaves methanol extract against planktonic and biofilm growth forms of Staphylococcus aureus. The antimicrobial activity was determined by the broth microdilution test. Minimal inhibitory concentrations and minimal bactericidal concentrations were detected against two collection and ten clinical S. aureus strains. Anti-biofilm activity of the tested extract was detected using 24 h bacterial biofilm on the surface of microtiter plate wells. The biofilm inhibitory activity was evaluated visually after 24 h interaction of extract with biofilm, and the eradicating activity by a regrowth method. The tested extract showed bactericidal activity against all S. aureus strains (methicillin susceptible or methicillin resistant) in concentrations ranging from 0.313 to 0.625 mg·mL(-1). Biofilm inhibitory concentrations were 10-times higher and biofilm eradicating concentrations 100-times higher (8 and 32 mg·mL(-1), respectively). The phytochemical analysis of C. coggygria leaves 60% methanol extract performed by LC-DAD-MS/MS revealed quercetin rhamnoside, methyl gallate, and methyl trigallate as main constituents. Results of our study indicate that C. coggygria, rich in tannins and flavonoids, seems to be a prospective topical antibacterial agent with anti-biofilm activity.}, } @article {pmid26728712, year = {2016}, author = {Mu, H and Tang, J and Liu, Q and Sun, C and Wang, T and Duan, J}, title = {Potent Antibacterial Nanoparticles against Biofilm and Intracellular Bacteria.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {18877}, pmid = {26728712}, issn = {2045-2322}, mesh = {Adsorption ; Animals ; Anti-Bacterial Agents/*administration & dosage/chemistry ; Bacteria/*drug effects ; Biofilms/*drug effects ; Cell Line ; *Gold/chemistry ; Macrophages/drug effects/microbiology ; *Metal Nanoparticles/chemistry/ultrastructure ; Mice ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects/ultrastructure ; Staphylococcus aureus/drug effects ; }, abstract = {The chronic infections related to biofilm and intracellular bacteria are always hard to be cured because of their inherent resistance to both antimicrobial agents and host defenses. Herein we develop a facile approach to overcome the above conundrum through phosphatidylcholine-decorated Au nanoparticles loaded with gentamicin (GPA NPs). The nanoparticles were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS) and ultraviolet-visible (UV-vis) absorption spectra which demonstrated that GPA NPs with a diameter of approximately 180 nm were uniform. The loading manner and release behaviors were also investigated. The generated GPA NPs maintained their antibiotic activities against planktonic bacteria, but more effective to damage established biofilms and inhibited biofilm formation of pathogens including Gram-positive and Gram-negative bacteria. In addition, GPA NPs were observed to be nontoxic to RAW 264.7 cells and readily engulfed by the macrophages, which facilitated the killing of intracellular bacteria in infected macrophages. These results suggested GPA NPs might be a promising antibacterial agent for effective treatment of chronic infections due to microbial biofilm and intracellular bacteria.}, } @article {pmid26728467, year = {2016}, author = {Chouhan, OP and Bandekar, D and Hazra, M and Baghudana, A and Hazra, S and Biswas, S}, title = {Effect of site-directed mutagenesis at the GGEEF domain of the biofilm forming GGEEF protein from Vibrio cholerae.}, journal = {AMB Express}, volume = {6}, number = {1}, pages = {2}, pmid = {26728467}, issn = {2191-0855}, abstract = {Vibrio cholerae, the cause of seven noted pandemics, leads a dual lifecycle-one in the human host in its virulent form, and the other as a sessile, non-virulent bacterium in aquatic bodies in surface biofilms. Surface biofilms have been attributed to be associated with a ubiquitous protein domain present in all branches of bacteria, known as the GGD(/E)EF domain. While the diguanlyate cyclase activities of these proteins are universally established, the role of these proteins as diguanlyate-specific phosphodiesterases in conjunction with a EAL domain has also been reported. The VC0395_0300 protein from V. cholerae which shows biofilm forming abilities also acts as a phosphodiesterase. Interestingly, this GGD(/E)EF protein contains a EAL site in the reverse orientation. We attempted to mutate the GGEEF signature along the sequence by site-directed mutagenesis. The resultant mutants (Sebox5-7) did not show much difference in phosphodiesterase activity in comparison with the wild type protein (Sebox3), indicating the independence of the phosphodiesterase activity of the protein from the GGD(/E)EF domain. However, the ability of the mutants to form surface biofilm was significantly lesser in the case of mutations in the three central positions of the signature domain.}, } @article {pmid26728027, year = {2016}, author = {Zhao, W and Dao, C and Karim, M and Gomez-Chiarri, M and Rowley, D and Nelson, DR}, title = {Contributions of tropodithietic acid and biofilm formation to the probiotic activity of Phaeobacter inhibens.}, journal = {BMC microbiology}, volume = {16}, number = {}, pages = {1}, pmid = {26728027}, issn = {1471-2180}, mesh = {Animals ; Bacterial Proteins/genetics/metabolism ; *Biofilms ; Ostreidae/growth & development/*microbiology ; Probiotics/*administration & dosage/metabolism ; Rhodobacteraceae/genetics/*physiology ; Tropolone/*analogs & derivatives/metabolism ; Vibrio/physiology ; Vibrio Infections/drug therapy/microbiology/*veterinary ; }, abstract = {BACKGROUND: The probiotic bacterium Phaeobacter inhibens strain S4Sm, isolated from the inner shell surface of a healthy oyster, secretes the antibiotic tropodithietic acid (TDA), is an excellent biofilm former, and increases oyster larvae survival when challenged with bacterial pathogens. In this study, we investigated the specific roles of TDA secretion and biofilm formation in the probiotic activity of S4Sm.

RESULTS: Mutations in clpX (ATP-dependent ATPase) and exoP (an exopolysaccharide biosynthesis gene) were created by insertional mutagenesis using homologous recombination. Mutation of clpX resulted in the loss of TDA production, no decline in biofilm formation, and loss of the ability to inhibit the growth of Vibrio tubiashii and Vibrio anguillarum in co-colonization experiments. Mutation of exoP resulted in a ~60% decline in biofilm formation, no decline in TDA production, and delayed inhibitory activity towards Vibrio pathogens in co-colonization experiments. Both clpX and exoP mutants exhibited reduced ability to protect oyster larvae from death when challenged by Vibrio tubiashii. Complementation of the clpX and exoP mutations restored the wild type phenotype. We also found that pre-colonization of surfaces by S4Sm was critical for this bacterium to inhibit pathogen colonization and growth.

CONCLUSIONS: Our observations demonstrate that probiotic activity by P. inhibens S4Sm involves contributions from both biofilm formation and the production of the antibiotic TDA. Further, probiotic activity also requires colonization of surfaces by S4Sm prior to the introduction of the pathogen.}, } @article {pmid26725755, year = {2016}, author = {Savijoki, K and Skogman, M and Fallarero, A and Nyman, TA and Sukura, A and Vuorela, P and Varmanen, P}, title = {Penicillin G increases the synthesis of a suicidal marker (CidC) and virulence (HlgBC) proteins in Staphylococcus aureus biofilm cells.}, journal = {International journal of medical microbiology : IJMM}, volume = {306}, number = {1}, pages = {69-74}, doi = {10.1016/j.ijmm.2015.11.006}, pmid = {26725755}, issn = {1618-0607}, mesh = {Anti-Bacterial Agents/*metabolism ; Bacterial Proteins/*biosynthesis ; Biofilms/*drug effects ; Electrophoresis, Gel, Two-Dimensional ; Microbial Viability/drug effects ; Penicillin G/*metabolism ; Proteome/analysis ; Staphylococcus aureus/*drug effects/physiology ; Virulence Factors/*biosynthesis ; }, abstract = {The present study reports the effect of Penicillin G (PenG) on the proteome dynamics of the Staphylococcus aureus strain Newman during biofilm mode of growth. The viability of the 18-h-old biofilm cells challenged with PenG at the concentration of 1mgmL(-1) was first assessed by plate counting, resazurin and LIVE/DEAD fluorescence staining, which indicated that the viability was reduced by ∼35% and ∼90% at 2h and 24h, respectively, after the addition of PenG. Subsequent two-dimensional difference gel electrophoresis (2D DIGE) assay of the treated and non-treated biofilm cells at the indicated time points revealed 45 proteins showing time- and treatment-specific change (1.5-fold, p<0.01). The 2D DIGE results suggested that the PenG-induced decrease in viability was accompanied by an increased synthesis of pyruvate oxidase (CidC), a suicidal marker known to potentiate acetate-dependent cell death in S. aureus. Increased abundance was also found for the TCA cycle associated malate-quinone oxidoreductase (Mqo), the ClpC ATPase, the HlgBC toxin and phage-associated proteins, which suggests that surviving cells have induced these activities as a last effort to overcome lethal doses of PenG. Proteomic results also revealed that the surviving cells were likely to strengthen their peptidoglycan due to the increased abundance of cell-wall biogenesis associated proteins, FemA and Pbp2; a phenomenon associated with dormancy in S. aureus.}, } @article {pmid26724739, year = {2016}, author = {Kafil, HS and Mobarez, AM and Moghadam, MF and Hashemi, ZS and Yousefi, M}, title = {Gentamicin induces efaA expression and biofilm formation in Enterococcus faecalis.}, journal = {Microbial pathogenesis}, volume = {92}, number = {}, pages = {30-35}, doi = {10.1016/j.micpath.2015.12.008}, pmid = {26724739}, issn = {1096-1208}, mesh = {Antigens, Bacterial/*genetics ; Bacterial Proteins/*genetics ; Biofilms/*drug effects ; Enterococcus faecalis/*drug effects/*physiology ; Gene Expression Regulation, Bacterial/*drug effects ; Gentamicins/*pharmacology ; Gram-Positive Bacterial Infections/microbiology ; Humans ; Microbial Sensitivity Tests ; }, abstract = {Enterococci have been ranked among the leading causes of nosocomial bacteremia and urinary tract infection. This study aimed to investigate the effect of ampicillin, vancomycin, gentamicin and ceftizoxime on biofilm formation and gene expression of colonization factors on Enterococcus faecalis. Twelve clinical isolates of E. faecalis were used to investigate the effect of antibiotics on biofilm formation and gene expression of efaA, asa1, ebpA, esp and ace. Flow system assay and Microtiter plates were used for biofilm assay. Two hundred clinical isolates were used for confirming the effect of antibiotics on biofilm formation. Ampicillin, vancomycin and ceftizoxime did not have any significant effect on biofilm formation, but gentamicin induced biofilm formation in 89% of isolates. In twelve selected isolate gentamicin increased expression of esp (+50.9%) and efaA (+33.9%) genes and reduced or maintained expression of others (asa1:-47.4%, ebpA: 0, ace:-19.2%). Vancomycin increased expression of esp (+89.1%) but reduced the others (asa1: -34.9%, ebpA:-11%, ace:-30%, efaA:-60%). Ceftizoxime increased slightly ebpA (+19.7%) and reduced others (asa1:-66.2%, esp:-35%, ace:-28.1%, efaA:-38.4%). and ampicillin strongly increased expression of ace (+231%), esp (+131%) and ebpA (+83%) but reduced others (asa1:-85.5%, efaA:-47.4%). The findings of the present study showed that antibiotics may have a role in biofilm formation and sustainability of enterococci, especially in case of gentamicin. efaA gene may have an important role, especially in antibiotic induced biofilm formation by gentamicin. Experiments with efaA mutants are needed to investigate the exact effect of efaA on biofilm formation with antibiotic induced cells.}, } @article {pmid26723911, year = {2016}, author = {Maiolo, EM and Oliva, A and Furustrand Tafin, U and Perrotet, N and Borens, O and Trampuz, A}, title = {Antifungal activity against planktonic and biofilm Candida albicans in an experimental model of foreign-body infection.}, journal = {The Journal of infection}, volume = {72}, number = {3}, pages = {386-392}, doi = {10.1016/j.jinf.2015.12.008}, pmid = {26723911}, issn = {1532-2742}, mesh = {Animals ; Antifungal Agents/*administration & dosage/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Candidiasis/*drug therapy/*microbiology ; Colony Count, Microbial ; Disease Models, Animal ; Foreign Bodies/*complications ; Guinea Pigs ; Injections, Intraperitoneal ; Male ; Treatment Outcome ; }, abstract = {OBJECTIVES: The treatment of Candida implant-associated infections remains challenging. We investigated the antifungal activity against planktonic and biofilm Candida albicans in a foreign-body infection model.

METHODS: Teflon cages were subcutaneously implanted in guinea pigs, infected with C. albicans (ATCC 90028). Animals were treated intraperitoneally 12 h after infection for 4 days once daily with saline, fluconazole (16 mg/kg), amphotericin B (2.5 mg/kg), caspofungin (2.5 mg/kg) or anidulafungin (20 mg/kg). Planktonic Candida was quantified, the clearance rate and cure rate determined.

RESULTS: In untreated animals, planktonic Candida was cleared from cage fluid in 25% (infected with 4.5 × 10(3) CFU/cage), 8% (infected with 4.8 × 10(4) CFU/cage) and 0% (infected with 6.2 × 10(5) CFU/cage). Candida biofilm persisted on all explanted cages. Compared to untreated controls, caspofungin reduced the number of planktonic C. albicans to 0.22 and 0.0 CFU/ml, respectively, and anidulafungin to 0.11 and 0.13 CFU/ml, respectively. Fluconazole cured 2/12 cages (17%), amphotericin B and anidulafungin 1/12 cages (8%) and caspofungin 3/12 cages (25%).

CONCLUSION: Echinocandins showed superior activity against planktonic C. albicans. Caspofungin showed the highest cure rate of C. albicans biofilm. However, no antifungal exceeded 25% cure rate, demonstrating the difficulty of eradicating Candida biofilms from implants.}, } @article {pmid26723483, year = {2016}, author = {de Almeida, J and Hoogenkamp, M and Felippe, WT and Crielaard, W and van der Waal, SV}, title = {Effectiveness of EDTA and Modified Salt Solution to Detach and Kill Cells from Enterococcus faecalis Biofilm.}, journal = {Journal of endodontics}, volume = {42}, number = {2}, pages = {320-323}, doi = {10.1016/j.joen.2015.11.017}, pmid = {26723483}, issn = {1878-3554}, mesh = {Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Dental Pulp Cavity/microbiology ; Edetic Acid/*pharmacology ; Enterococcus faecalis/*drug effects/physiology ; Microbial Viability/drug effects ; Real-Time Polymerase Chain Reaction ; Root Canal Irrigants/pharmacology ; Sodium Chloride/*pharmacology ; Sorbic Acid/*pharmacology ; }, abstract = {INTRODUCTION: Disruption of the matrix of endodontic biofilms will aid in their removal from a root canal. Therefore, the aim of this study was to investigate the efficacy of EDTA and a modified salt solution (MSS) to detach bacteria from biofilms.

METHODS: Forty-eight-hour-old Enterococcus faecalis biofilms were grown on glass coverslips and then treated for 1 hour by immersion in 17% EDTA or MSS. Phosphate-buffered saline served as a negative control. Then, residual biofilm cells on the substrate and the detached cells in the supernatant were collected. Viability was verified by the colony-forming unit (CFU) counting method. Propidium monoazide (PMA) treatment in conjunction with quantitative polymerase chain reaction (qPCR) was also performed to detect the presence of E. faecalis 16S ribonucleic RNA genes. Data were analyzed using 1-way analysis of variance and Tukey or Kruskal-Wallis and Dunn tests. The Pearson R test evaluated the correlation between results from CFU and PMA (α = 5%).

RESULTS: qPCR showed that EDTA detached 99% of biofilm cells, and MSS detached 94% of biofilm cells (both P < .001). In contrast to EDTA, MSS was highly antimicrobial. The treatment promoted an ample log 7 reduction of the attached cells (P < .001), and almost no live cells were detected in the supernatant (P < .001). Positive correlations between CFU and qPCR with PMA were observed (r = 0.959 and r = 0.729).

CONCLUSIONS: EDTA detached cells in biofilms with a minor antimicrobial effect. Besides a great antimicrobial effect, MSS also detached biofilm cells. These dispersals of biofilms give insights into new endodontic biofilm removal strategies.}, } @article {pmid26721183, year = {2016}, author = {Paterson, JS and Ogden, S and Smith, RJ and Delpin, MW and Mitchell, JG and Quinton, JS}, title = {Surface modification of an organic hessian substrate leads to shifts in bacterial biofilm community composition and abundance.}, journal = {Journal of biotechnology}, volume = {219}, number = {}, pages = {90-97}, doi = {10.1016/j.jbiotec.2015.12.033}, pmid = {26721183}, issn = {1873-4863}, mesh = {Biofilms/*drug effects ; Biofouling/prevention & control ; Phyllobacteriaceae/genetics/isolation & purification/*physiology ; RNA, Ribosomal, 16S/analysis ; Sequence Analysis, RNA ; Silanes/chemistry/*pharmacology ; Sodium Hydroxide/*chemistry ; Surface Properties ; Water Microbiology ; }, abstract = {Antifouling strategies to limit biofilms on submerged surfaces in the marine environment are of particular interest due to the economic and environmental impacts in industries such as shipping and aquaculture. Here, we investigate the influence of chemically modified hessian bag surfaces on the bacterial abundance and community composition of biofilm formation using flow cytometry and 16S rRNA pyrosequencing. Hessian bags were coated with 5% and 10% Propyl(trimethoxy)silane (PTMS) and half of the bags had their lignin and hemicellulose removed via NaOH mercerisation. Significantly lower bacterial abundance was observed on mercerised bags treated with 5% PTMS (p<0.01). Significant shifts in bacterial taxa were also observed (p=0.0004), whereby unmercerised bags exhibited higher relative abundances of the anaerobic family Desulfovibrionaceae (4.5±1.7%), while mercerised bags displayed higher relative abundances of the aerobic family Phyllobacteriaceae (3.6±1.7%). This suggests that the mercerisation process may lower colonization rates and subsequently produce a thinner biofilm. This hypothesis is strengthened by the lower abundance of bacteria on mercerised bags, particularly on the 5% PTMS coating. Our results show that modifying a hessian surface via non-toxic coating and mercerisation reduces biofilm formation and also shifts the dominant taxa, increasing our understanding of antifouling strategies in the marine environment.}, } @article {pmid26720877, year = {2015}, author = {Heidari, AE and Moghaddam, S and Truong, KK and Chou, L and Genberg, C and Brenner, M and Chen, Z}, title = {Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography.}, journal = {Journal of biomedical optics}, volume = {20}, number = {12}, pages = {126010}, pmid = {26720877}, issn = {1560-2281}, support = {P41 EB-015890/EB/NIBIB NIH HHS/United States ; P41 EB015890/EB/NIBIB NIH HHS/United States ; R01 HL127271/HL/NHLBI NIH HHS/United States ; R01 HL105215/HL/NHLBI NIH HHS/United States ; R01 HL-125084/HL/NHLBI NIH HHS/United States ; R01 HL125084/HL/NHLBI NIH HHS/United States ; R01 HL-105215/HL/NHLBI NIH HHS/United States ; R01 EY021529/EY/NEI NIH HHS/United States ; R01 EY-021529/EY/NEI NIH HHS/United States ; }, mesh = {Artifacts ; *Biofilms ; Critical Care ; Cross Infection/diagnosis ; Endoscopy/*methods ; *Equipment Contamination ; Humans ; Image Processing, Computer-Assisted/methods ; Imaging, Three-Dimensional/methods ; Intensive Care Units ; Interferometry/methods ; Intubation, Intratracheal/*adverse effects ; Microscopy, Electron, Scanning ; Phenotype ; Pneumonia, Ventilator-Associated/diagnosis ; Tomography, Optical Coherence/*methods ; }, abstract = {Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients’ endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.}, } @article {pmid26719448, year = {2016}, author = {Ferris, RA and McCue, PM and Borlee, GI and Loncar, KD and Hennet, ML and Borlee, BR}, title = {In Vitro Efficacy of Nonantibiotic Treatments on Biofilm Disruption of Gram-Negative Pathogens and an In Vivo Model of Infectious Endometritis Utilizing Isolates from the Equine Uterus.}, journal = {Journal of clinical microbiology}, volume = {54}, number = {3}, pages = {631-639}, pmid = {26719448}, issn = {1098-660X}, mesh = {Acetylcysteine/pharmacology ; Animals ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects/*growth & development ; Biomass ; *Disease Models, Animal ; Edetic Acid/pharmacology ; Endometritis/*drug therapy/*microbiology ; Female ; Gram-Negative Bacteria/isolation & purification/*physiology ; Horses ; Hydrogen Peroxide/pharmacology ; Luminescent Measurements ; Microbial Viability/drug effects ; Staining and Labeling/methods ; Uterus/microbiology ; }, abstract = {In this study, we evaluated the ability of the equine clinical treatments N-acetylcysteine, EDTA, and hydrogen peroxide to disrupt in vitro biofilms and kill equine reproductive pathogens (Escherichia coli, Pseudomonas aeruginosa, or Klebsiella pneumoniae) isolated from clinical cases. N-acetylcysteine (3.3%) decreased biofilm biomass and killed bacteria within the biofilms of E. coli isolates. The CFU of recoverable P. aeruginosa and K. pneumoniae isolates were decreased, but the biofilm biomass was unchanged. Exposure to hydrogen peroxide (1%) decreased the biofilm biomass and reduced the CFU of E. coli isolates, K. pneumoniae isolates were observed to have a reduction in CFU, and minimal effects were observed for P. aeruginosa isolates. Chelating agents (EDTA formulations) reduced E. coli CFU but were ineffective at disrupting preformed biofilms or decreasing the CFU of P. aeruginosa and K. pneumoniae within a biofilm. No single nonantibiotic treatment commonly used in equine veterinary practice was able to reduce the CFU and biofilm biomass of all three Gram-negative species of bacteria evaluated. An in vivo equine model of infectious endometritis was also developed to monitor biofilm formation, utilizing bioluminescence imaging with equine P. aeruginosa isolates from this study. Following infection, the endometrial surface contained focal areas of bacterial growth encased in a strongly adherent "biofilm-like" matrix, suggesting that biofilms are present during clinical cases of infectious equine endometritis. Our results indicate that Gram-negative bacteria isolated from the equine uterus are capable of producing a biofilm in vitro, and P. aeruginosa is capable of producing biofilm-like material in vivo.}, } @article {pmid26719437, year = {2016}, author = {Olivares, E and Badel-Berchoux, S and Provot, C and Jaulhac, B and Prévost, G and Bernardi, T and Jehl, F}, title = {The BioFilm Ring Test: a Rapid Method for Routine Analysis of Pseudomonas aeruginosa Biofilm Formation Kinetics.}, journal = {Journal of clinical microbiology}, volume = {54}, number = {3}, pages = {657-661}, pmid = {26719437}, issn = {1098-660X}, mesh = {Bacterial Adhesion ; *Bacteriological Techniques ; *Biofilms ; Cystic Fibrosis/complications ; Humans ; Pseudomonas Infections/*diagnosis/*microbiology ; Pseudomonas aeruginosa/isolation & purification/*physiology ; Sputum/microbiology ; }, abstract = {Currently, few techniques are available for the evaluation of bacterial biofilm adhesion. These detection tools generally require time for culture and/or arduous handling steps. In this work, the BioFilm Ring Test (BRT), a new technology, was used to estimate the biofilm formation kinetics of 25 strains of Pseudomonas aeruginosa, isolated from the sputum of cystic fibrosis (CF) patients. The principle of the new assay is based on the mobility measurement of magnetic microbeads mixed with a bacterial suspension in a polystyrene microplate. If free to move under the magnetic action, particles gather to a visible central spot in the well bottom. Therefore, the absence of spot formation in the plate reflects the bead immobilization by a biofilm in formation. The BRT device allowed us to classify the bacterial strains into three general adhesion profiles. Group 1 consists of bacteria, which are able to form a solid biofilm in <2 h. Group 2 comprises the strains that progressively set up a biofilm during 24 h. Lastly, group 3 includes the strains that stay in a planktonic form. The grouping of our strains did not differ according to culture conditions, i.e., the use of different sets of beads or culture media. The BRT is shown to be an informative tool for the characterization of biofilm-forming bacteria. Various application perspectives may be investigated for this device, such as the addition of antibiotics to the bacterial suspension to select which would have the ability to inhibit the biofilm formation.}, } @article {pmid26715750, year = {2016}, author = {Formosa-Dague, C and Speziale, P and Foster, TJ and Geoghegan, JA and Dufrêne, YF}, title = {Zinc-dependent mechanical properties of Staphylococcus aureus biofilm-forming surface protein SasG.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {2}, pages = {410-415}, pmid = {26715750}, issn = {1091-6490}, mesh = {Bacterial Adhesion/drug effects ; Bacterial Proteins/chemistry/*metabolism ; Biofilms/*drug effects ; Biomechanical Phenomena/drug effects ; Biophysical Phenomena/drug effects ; Cell Membrane/drug effects/metabolism ; Cell Wall/drug effects/metabolism ; Membrane Proteins/chemistry/*metabolism ; Microscopy, Atomic Force ; Models, Biological ; Protein Structure, Tertiary ; Staphylococcus aureus/drug effects/*physiology ; Zinc/*pharmacology ; }, abstract = {Staphylococcus aureus surface protein SasG promotes cell-cell adhesion during the accumulation phase of biofilm formation, but the molecular basis of this interaction remains poorly understood. Here, we unravel the mechanical properties of SasG on the surface of living bacteria, that is, in its native cellular environment. Nanoscale multiparametric imaging of living bacteria reveals that Zn(2+) strongly increases cell wall rigidity and activates the adhesive function of SasG. Single-cell force measurements show that SasG mediates cell-cell adhesion via specific Zn(2+)-dependent homophilic bonds between β-sheet-rich G5-E domains on neighboring cells. The force required to unfold individual domains is remarkably strong, up to ∼500 pN, thus explaining how SasG can withstand physiological shear forces. We also observe that SasG forms homophilic bonds with the structurally related accumulation-associated protein of Staphylococcus epidermidis, suggesting the possibility of multispecies biofilms during host colonization and infection. Collectively, our findings support a model in which zinc plays a dual role in activating cell-cell adhesion: adsorption of zinc ions to the bacterial cell surface increases cell wall cohesion and favors the projection of elongated SasG proteins away from the cell surface, thereby enabling zinc-dependent homophilic bonds between opposing cells. This work demonstrates an unexpected relationship between mechanics and adhesion in a staphylococcal surface protein, which may represent a general mechanism among bacterial pathogens for activating cell association.}, } @article {pmid26715638, year = {2015}, author = {Ouyang, J and Xiong, L and Feng, W and Sun, F and Chen, Y}, title = {[Effects of inhibitory peptide of Staphylococcus epidermidis biofilm on adhesion and biofilm formation of this bacterium].}, journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns}, volume = {31}, number = {4}, pages = {285-289}, pmid = {26715638}, issn = {1009-2587}, mesh = {Bacterial Adhesion ; Biofilms/*growth & development ; Humans ; Microscopy, Confocal ; *Peptides ; Staphylococcus epidermidis/genetics/metabolism/*physiology ; }, abstract = {OBJECTIVE: To study the effects of inhibitory peptide of Staphylococcus epidermidis (SE) biofilm (briefly referred to as inhibitory peptide) on adhesion and biofilm formation of SE at early stage.

METHODS: By using peptide synthesizer, the inhibitory peptide was synthesized with purity of 96.8% and relative molecular mass of 874.4. (1) Solution of SE ATCC 35984 (the same below) was cultivated with inhibitory peptide in the final concentrations of 1-256 µg/mL, and the M-H broth without bacteria solution was used as blank control. The MIC of the inhibitory peptide against SE was determined (n=3). (2) Solution of SE was cultivated with trypticase soy broth (TSB) culture solution containing inhibitory peptide in the final concentrations of 16, 32, 64, 128, and 256 µg/mL (set as inhibitory peptide groups in corresponding concentration), and solution of SE being cultivated with TSB culture medium was used as negative control group. Growth of SE was observed every one hour from immediately after cultivation (denoted as absorbance value), and the growth curve of SE during the 24 hours of cultivation was drawn, with 3 samples in each group at each time point. (3) Solution of SE was cultivated with TSB culture solution containing inhibitory peptide in the final concentrations of 16, 32, 64, 128, and 256 µg/mL (set as inhibitory peptide groups in corresponding concentration), and solution of SE being cultivated with TSB culture medium was used as negative control group. Adhesive property of SE was observed after cultivation for 4 hours (denoted as absorbance value, n=10); biofilm formation of SE was observed after cultivation for 20 hours (denoted as absorbance value, n=10). (4) Solution of SE was cultivated with TSB culture solution containing inhibitory peptide in the final concentration of 128 µg/mL (set as 128 µg/mL inhibitory peptide group), and solution of SE being cultivated with TSB culture medium was used as negative control group. Adhesive property of SE and its biofilm formation were observed with confocal laser scanning microscope (CLSM), and the sample numbers were both 3. Data were processed with one-way analysis of variance, LSD test, and Dunnett T3 test.

RESULTS: (1) The MIC of inhibitory peptide against SE exceeded 256 µg/mL. (2) There was no significant difference in the growth curve of SE between inhibitory peptide groups in different concentrations and negative control group. (3) After 4 hours of cultivation, the absorbance values of adhesive property of SE in 256, 128, 64, and 32 µg/mL inhibitory peptide groups were respectively 0.20 ± 0.04, 0.27 ± 0.03, 0.35 ± 0.04, and 0.40 ± 0.04, which were significantly lower than the absorbance value in negative control group (0.53 ± 0.10, P<0.05 or P<0.01); the absorbance value of adhesive property of SE in 16 µg/mL inhibitory peptide group was 0.47 ± 0.09, which was close to the absorbance value in negative control group (P>0.05). After 20 hours of cultivation, the absorbance values of biofilm formation of SE in 256, 128, and 64 µg/mL inhibitory peptide groups were respectively 0.49 ± 0.10, 0.68 ± 0.06, and 0.93 ± 0.13, which were significantly less than the absorbance value in negative control group (1.21 ± 0.18, P<0.05 or P<0.01); the absorbance values of biofilm formation in 32 and 16 µg/mL inhibitory peptide groups were respectively 1.18 ± 0.22 and 1.15 ± 0.26, which were close to the absorbance value in negative control group (with P values above 0.05). (4) CLSM showed that more adhering bacteria and compact structure of biofilm were observed in negative control group, but less adhering bacteria and loose structure of biofilm were observed in 128 µg/mL inhibitory peptide group.

CONCLUSIONS: The inhibitory peptide can inhibit adhesion and biofilm formation of SE at early stage, but its structure still needs to be further modified.}, } @article {pmid26713438, year = {2015}, author = {Kim, D and Hwang, G and Liu, Y and Wang, Y and Singh, AP and Vorsa, N and Koo, H}, title = {Cranberry Flavonoids Modulate Cariogenic Properties of Mixed-Species Biofilm through Exopolysaccharides-Matrix Disruption.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0145844}, pmid = {26713438}, issn = {1932-6203}, support = {R01 DE016139/DE/NIDCR NIH HHS/United States ; S10 RR027128/RR/NCRR NIH HHS/United States ; 5R01DE016139/DE/NIDCR NIH HHS/United States ; S10RR027128/RR/NCRR NIH HHS/United States ; }, mesh = {Apatites/metabolism ; Biofilms/*drug effects/*growth & development ; Biomechanical Phenomena/drug effects ; Flavonoids/*pharmacology ; Polysaccharides, Bacterial/*metabolism ; Streptococcus mutans/drug effects/metabolism/physiology ; Vaccinium macrocarpon/*chemistry ; }, abstract = {The exopolysaccharides (EPS) produced by Streptococcus mutans-derived glucosyltransferases (Gtfs) are essential virulence factors associated with the initiation of cariogenic biofilms. EPS forms the core of the biofilm matrix-scaffold, providing mechanical stability while facilitating the creation of localized acidic microenvironments. Cranberry flavonoids, such as A-type proanthocyanidins (PACs) and myricetin, have been shown to inhibit the activity of Gtfs and EPS-mediated bacterial adhesion without killing the organisms. Here, we investigated whether a combination of cranberry flavonoids disrupts EPS accumulation and S. mutans survival using a mixed-species biofilm model under cariogenic conditions. We also assessed the impact of cranberry flavonoids on mechanical stability and the in situ pH at the biofilm-apatite interface. Topical application of an optimized combination of PACs oligomers (100-300 μM) with myricetin (2 mM) twice daily was used to simulate treatment regimen experienced clinically. Treatments with cranberry flavonoids effectively reduced the insoluble EPS content (>80% reduction vs. vehicle-control; p<0.001), while hindering S. mutans outgrowth within mixed-species biofilms. As a result, the 3D architecture of cranberry-treated biofilms was severely compromised, showing a defective EPS-matrix and failure to develop microcolonies on the saliva-coated hydroxyapatite (sHA) surface. Furthermore, topical applications of cranberry flavonoids significantly weaken the mechanical stability of the biofilms; nearly 90% of the biofilm was removed from sHA surface after exposure to a shear stress of 0.449 N/m2 (vs. 36% removal in vehicle-treated biofilms). Importantly, in situ pH measurements in cranberry-treated biofilms showed significantly higher pH values (5.2 ± 0.1) at the biofilm-apatite interface vs. vehicle-treated biofilms (4.6 ± 0.1). Altogether, the data provide important insights on how cranberry flavonoids treatments modulate virulence properties by disrupting the biochemical and ecological changes associated with cariogenic biofilm development, which could lead to new alternative or adjunctive antibiofilm/anticaries chemotherapeutic formulations.}, } @article {pmid26712936, year = {2015}, author = {Heindl, JE and Hibbing, ME and Xu, J and Natarajan, R and Buechlein, AM and Fuqua, C}, title = {Discrete Responses to Limitation for Iron and Manganese in Agrobacterium tumefaciens: Influence on Attachment and Biofilm Formation.}, journal = {Journal of bacteriology}, volume = {198}, number = {5}, pages = {816-829}, pmid = {26712936}, issn = {1098-5530}, support = {GM080546/GM/NIGMS NIH HHS/United States ; T32 GM007757/GM/NIGMS NIH HHS/United States ; 1 F32 GM100601/GM/NIGMS NIH HHS/United States ; R01 GM080546/GM/NIGMS NIH HHS/United States ; T32-GM007757/GM/NIGMS NIH HHS/United States ; F32 GM100601/GM/NIGMS NIH HHS/United States ; }, mesh = {Agrobacterium tumefaciens/drug effects/*physiology ; Bacterial Adhesion/drug effects/physiology ; Bacterial Proteins/genetics/metabolism ; Biofilms/drug effects/*growth & development ; Gene Expression Regulation, Bacterial/drug effects/physiology ; Iron/administration & dosage/*metabolism/pharmacology ; Manganese/administration & dosage/*metabolism/pharmacology ; Transcriptome ; }, abstract = {UNLABELLED: Transition metals such as iron and manganese are crucial trace nutrients for the growth of most bacteria, functioning as catalytic cofactors for many essential enzymes. Dedicated uptake and regulatory systems have evolved to ensure their acquisition for growth, while preventing toxicity. Transcriptomic analysis of the iron- and manganese-responsive regulons of Agrobacterium tumefaciens revealed that there are discrete regulatory networks that respond to changes in iron and manganese levels. Complementing earlier studies, the iron-responsive gene network is quite large and includes many aspects of iron-dependent metabolism and the iron-sparing response. In contrast, the manganese-responsive network is restricted to a limited number of genes, many of which can be linked to transport and utilization of the transition metal. Several of the target genes predicted to drive manganese uptake are required for growth under manganese-limited conditions, and an A. tumefaciens mutant with a manganese transport deficiency is attenuated for plant virulence. Iron and manganese limitation independently inhibit biofilm formation by A. tumefaciens, and several candidate genes that could impact biofilm formation were identified in each regulon. The biofilm-inhibitory effects of iron and manganese do not rely on recognized metal-responsive transcriptional regulators, suggesting alternate mechanisms influencing biofilm formation. However, under low-manganese conditions the dcpA operon is upregulated, encoding a system that controls levels of the cyclic di-GMP second messenger. Mutation of this regulatory pathway dampens the effect of manganese limitation.

IMPORTANCE: Responses to changes in transition metal levels, such as those of manganese and iron, are important for normal metabolism and growth in bacteria. Our study used global gene expression profiling to understand the response of the plant pathogen Agrobacterium tumefaciens to changes of transition metal availability. Among the properties that are affected by both iron and manganese levels are those required for normal surface attachment and biofilm formation, but the requirement for each of these transition metals is mechanistically independent from the other.}, } @article {pmid26712734, year = {2015}, author = {Ta, CA and Arnason, JT}, title = {Mini Review of Phytochemicals and Plant Taxa with Activity as Microbial Biofilm and Quorum Sensing Inhibitors.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {1}, pages = {E29}, pmid = {26712734}, issn = {1420-3049}, mesh = {Anti-Bacterial Agents/pharmacology ; Biofilms/*drug effects ; Monoterpenes/pharmacology ; Phenols/pharmacology ; Phytochemicals/*pharmacology ; Plant Extracts/pharmacology ; Quorum Sensing/*drug effects ; Tracheophyta/*chemistry ; }, abstract = {Microbial biofilms readily form on many surfaces in nature including plant surfaces. In order to coordinate the formation of these biofilms, microorganisms use a cell-to-cell communication system called quorum sensing (QS). As formation of biofilms on vascular plants may not be advantageous to the hosts, plants have developed inhibitors to interfere with these processes. In this mini review, research papers published on plant-derived molecules that have microbial biofilm or quorum sensing inhibition are reviewed with the objectives of determining the biosynthetic classes of active compounds, their biological activity in assays, and their families of occurrence and range. The main findings are the identification of plant phenolics, including benzoates, phenyl propanoids, stilbenes, flavonoids, gallotannins, proanthocyanidins and coumarins as important inhibitors with both activities. Some terpenes including monoterpenes, sesquiterpenes, diterpenes and triterpenes also have anti-QS and anti-biofilm activities. Relatively few alkaloids were reported. Quinones and organosulfur compounds, especially from garlic, were also active. A common feature is the polar nature of these compounds. Phytochemicals with these activities are widespread in Angiosperms in temperate and tropical regions, but gymnosperms, bryophytes and pteridophytes were not represented.}, } @article {pmid26712726, year = {2015}, author = {Bernegossi, J and Calixto, GM and Sanches, PR and Fontana, CR and Cilli, EM and Garrido, SS and Chorilli, M}, title = {Peptide KSL-W-Loaded Mucoadhesive Liquid Crystalline Vehicle as an Alternative Treatment for Multispecies Oral Biofilm.}, journal = {Molecules (Basel, Switzerland)}, volume = {21}, number = {1}, pages = {E37}, pmid = {26712726}, issn = {1420-3049}, mesh = {Animals ; Antimicrobial Cationic Peptides/*administration & dosage/*chemistry/pharmacology ; Biofilms/*drug effects ; Cattle ; Excipients ; Liquid Crystals/*chemistry ; Mouth/drug effects/*microbiology ; Scattering, Small Angle ; Surface-Active Agents ; X-Ray Diffraction ; }, abstract = {Decapeptide KSL-W shows antibacterial activities and can be used in the oral cavity, however, it is easily degraded in aqueous solution and eliminated. Therefore, we aimed to develop liquid crystalline systems (F1 and F2) for KSL-W buccal administration to treat multispecies oral biofilms. The systems were prepared with oleic acid, polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol (PPG-5-CETETH-20), and a 1% poloxamer 407 dispersion as the oil phase (OP), surfactant (S), and aqueous phase (AP), respectively. We characterized them using polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, and in vitro bioadhesion, and performed in vitro biological analysis. PLM showed isotropy (F1) or anisotropy with lamellar mesophases (F2), confirmed by peak ratio quantification using SAXS. Rheological tests demonstrated that F1 exhibited Newtonian behavior but not F2, which showed a structured AP concentration-dependent system. Bioadhesion studies revealed an AP concentration-dependent increase in the system's bioadhesiveness (F2 = 15.50 ± 1.00 mN·s) to bovine teeth blocks. Antimicrobial testing revealed 100% inhibition of multispecies oral biofilm growth after KSL-W administration, which was incorporated in the F2 aqueous phase at a concentration of 1 mg/mL. Our results suggest that this system could serve as a potential vehicle for buccal administration of antibiofilm peptides.}, } @article {pmid26712549, year = {2015}, author = {Vogeleer, P and Tremblay, YDN and Jubelin, G and Jacques, M and Harel, J}, title = {Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections.}, journal = {Applied and environmental microbiology}, volume = {82}, number = {5}, pages = {1448-1458}, pmid = {26712549}, issn = {1098-5336}, mesh = {Agglutination ; Biofilms/*growth & development ; Disinfectants/pharmacology ; Escherichia coli Infections/microbiology ; Escherichia coli Proteins/genetics ; Genes, Bacterial ; Genotype ; Humans ; Microbial Viability/drug effects ; Microscopy, Confocal ; Serogroup ; Shiga-Toxigenic Escherichia coli/drug effects/genetics/*isolation & purification/*physiology ; }, abstract = {Forming biofilms may be a survival strategy of Shiga toxin-producing Escherichia coli to enable it to persist in the environment and the food industry. Here, we evaluate and characterize the biofilm-forming ability of 39 isolates of Shiga toxin-producing Escherichia coli isolates recovered from human infection and belonging to seropathotypes A, B, or C. The presence and/or production of biofilm factors such as curli, cellulose, autotransporter, and fimbriae were investigated. The polymeric matrix of these biofilms was analyzed by confocal microscopy and by enzymatic digestion. Cell viability and matrix integrity were examined after sanitizer treatments. Isolates of the seropathotype A (O157:H7 and O157:NM), which have the highest relative incidence of human infection, had a greater ability to form biofilms than isolates of seropathotype B or C. Seropathotype A isolates were unique in their ability to produce cellulose and poly-N-acetylglucosamine. The integrity of the biofilms was dependent on proteins. Two autotransporter genes, ehaB and espP, and two fimbrial genes, z1538 and lpf2, were identified as potential genetic determinants for biofilm formation. Interestingly, the ability of several isolates from seropathotype A to form biofilms was associated with their ability to agglutinate yeast in a mannose-independent manner. We consider this an unidentified biofilm-associated factor produced by those isolates. Treatment with sanitizers reduced the viability of Shiga toxin-producing Escherichia coli but did not completely remove the biofilm matrix. Overall, our data indicate that biofilm formation could contribute to the persistence of Shiga toxin-producing Escherichia coli and specifically seropathotype A isolates in the environment.}, } @article {pmid26712337, year = {2017}, author = {Tran, PL and Huynh, E and Hamood, AN and de Souza, A and Schultz, G and Liesenfeld, B and Mehta, D and Webster, D and Reid, TW}, title = {The ability of quaternary ammonium groups attached to a urethane bandage to inhibit bacterial attachment and biofilm formation in a mouse wound model.}, journal = {International wound journal}, volume = {14}, number = {1}, pages = {79-84}, pmid = {26712337}, issn = {1742-481X}, mesh = {Animals ; Bacterial Infections/*therapy ; Biofilms/*drug effects ; Dimethylamines/*therapeutic use ; Disease Models, Animal ; Mice ; *Occlusive Dressings ; Urethane ; Wound Healing/*physiology ; Wound Infection/microbiology/*therapy ; Wounds and Injuries/*therapy ; }, abstract = {For proper wound healing, control of bacteria or bacterial infections is of major importance. While caring for a wound, dressing material plays a key role as bacteria can live in the bandage and keep re-infecting the wound. They do this by forming biofilms in the bandage, which slough off planktonic bacteria and overwhelm the host defense. It is thus necessary to develop a wound dressing that will inhibit bacterial growth. This study examines the effectiveness of a polyurethane foam wound dressing bound with polydiallyl-dimethylammonium chloride (pDADMAC) to inhibit the growth of bacteria in a wound on the back of a mouse. This technology does not allow pDADMAC to leach away from the dressing into the wound, thereby preventing cytotoxic effects. Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii were chosen for the study to infect the wounds. S. aureus and P. aeruginosa are important pathogens in wound infections, while A. baumannii was selected because of its ability to acquire or upregulate antibiotic drug resistance determinants. In addition, two different isolates of methicillin-resistant S. aureus (MRSA) were tested. All the bacteria were measured in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over six logs of inhibition (100%) were found for all the bacterial strains using pDADMAC-treated wound dressing when compared with control-untreated dressing. The CFU assay results obtained with the tissues were significant as there were 4-5 logs of reduction (100%) of the test organism in the tissue of the pDADMAC-covered wound versus that of the control dressing-covered wound. As the pDADMAC cannot leave the dressing (like other antimicrobials), this would imply that the dressing acts as a reservoir for free bacteria from a biofilm and plays a significant role in the development of a wound infection.}, } @article {pmid26712005, year = {2016}, author = {Matsuyama, BY and Krasteva, PV and Baraquet, C and Harwood, CS and Sondermann, H and Navarro, MV}, title = {Mechanistic insights into c-di-GMP-dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {2}, pages = {E209-18}, pmid = {26712005}, issn = {1091-6490}, support = {P41 GM103403/GM/NIGMS NIH HHS/United States ; R01-GM56665/GM/NIGMS NIH HHS/United States ; P41 GM103485/GM/NIGMS NIH HHS/United States ; P41-GM103403/GM/NIGMS NIH HHS/United States ; R01 AI097307/AI/NIAID NIH HHS/United States ; R01-AI097307/AI/NIAID NIH HHS/United States ; GM-103485/GM/NIGMS NIH HHS/United States ; R01 GM056665/GM/NIGMS NIH HHS/United States ; }, mesh = {Amino Acid Motifs ; Amino Acid Sequence ; Bacterial Proteins/chemistry/*metabolism ; Base Sequence ; Binding Sites ; Biofilms/*drug effects ; Calorimetry ; Conserved Sequence ; Cross-Linking Reagents ; Crystallography, X-Ray ; Cyclic GMP/*analogs & derivatives/pharmacology ; DNA, Bacterial/metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Mutant Proteins/chemistry ; Promoter Regions, Genetic/genetics ; Protein Multimerization/drug effects ; Protein Stability ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Pseudomonas aeruginosa/drug effects/genetics/*physiology ; Sequence Alignment ; Solutions ; Temperature ; Trans-Activators/chemistry/*metabolism ; Transcription, Genetic ; }, abstract = {Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ(54)-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response to cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ's AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP-complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs.}, } @article {pmid26711808, year = {2016}, author = {Zhu, H and Mao, XJ and Guo, XP and Sun, YC}, title = {The hmsT 3' untranslated region mediates c-di-GMP metabolism and biofilm formation in Yersinia pestis.}, journal = {Molecular microbiology}, volume = {99}, number = {6}, pages = {1167-1178}, doi = {10.1111/mmi.13301}, pmid = {26711808}, issn = {1365-2958}, mesh = {*3' Untranslated Regions ; Bacterial Proteins/*genetics/metabolism ; *Biofilms ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/metabolism ; Phosphorus-Oxygen Lyases/metabolism ; Yersinia pestis/genetics/metabolism/*physiology ; }, abstract = {Yersinia pestis, the cause of plague, forms a biofilm in the proventriculus of its flea vector to enhance transmission. Biofilm formation in Y. pestis is regulated by the intracellular levels of cyclic diguanylate (c-di-GMP). In this study, we investigated the role of the 3' untranslated region (3'UTR) in hmsT mRNA, a transcript that encodes a diguanylate cyclase that stimulates biofilm formation in Y. pestis by synthesizing the second messenger c-di-GMP. Deletion of the 3'UTR increased the half-life of hmsT mRNA, thereby upregulating c-di-GMP levels and biofilm formation. Our findings indicate that multiple regulatory sequences might be present in the hmsT 3'UTR that function together to mediate mRNA turnover. We also found that polynucleotide phosphorylase is partially responsible for hmsT 3'UTR-mediated mRNA decay. In addition, the hmsT 3'UTR strongly repressed gene expression at 37°C and 26°C, but affected gene expression only slightly at 21°C. Our findings suggest that the 3'UTR might be involved in precise and rapid regulation of hmsT expression, allowing Y. pestis to fine-tune c-di-GMP synthesis and consequently regulate biofilm production to adapt to the changing host environment.}, } @article {pmid26711774, year = {2015}, author = {Furiga, A and Lajoie, B and El Hage, S and Baziard, G and Roques, C}, title = {Impairment of Pseudomonas aeruginosa Biofilm Resistance to Antibiotics by Combining the Drugs with a New Quorum-Sensing Inhibitor.}, journal = {Antimicrobial agents and chemotherapy}, volume = {60}, number = {3}, pages = {1676-1686}, pmid = {26711774}, issn = {1098-6596}, mesh = {Amides/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Adhesion/*drug effects ; Biofilms/*drug effects ; Ciprofloxacin/pharmacology ; Colistin/pharmacology ; Cystic Fibrosis/microbiology ; Drug Synergism ; Drug Therapy, Combination ; Humans ; Lung/microbiology/pathology ; Microscopy, Confocal ; Pseudomonas Infections/*drug therapy ; Pseudomonas aeruginosa/*drug effects/pathogenicity ; Pyrimidines/*pharmacology ; Quorum Sensing/*drug effects ; Respiratory Tract Infections/*drug therapy/microbiology ; Tobramycin/pharmacology ; }, abstract = {Pseudomonas aeruginosa plays an important role in chronic lung infections among patients with cystic fibrosis (CF) through its ability to form antibiotic-resistant biofilms. In P. aeruginosa, biofilm development and the production of several virulence factors are mainly regulated by the rhl and las quorum-sensing (QS) systems, which are controlled by two N-acyl-homoserine lactone signal molecules. In a previous study, we discovered an original QS inhibitor, N-(2-pyrimidyl)butanamide, called C11, based on the structure of C4-homoserine lactone, and found that it is able to significantly inhibit P. aeruginosa biofilm formation. However, recent data indicate that P. aeruginosa grows under anaerobic conditions and forms biofilms in the lungs of CF patients that are denser and more robust than those formed under aerobic conditions. Our confocal microscopy observations of P. aeruginosa biofilms developed under aerobic and anaerobic conditions confirmed that the biofilms formed under these two conditions have radically different architectures. C11 showed significant dose-dependent antibiofilm activity on biofilms grown under both aerobic and anaerobic conditions, with a greater inhibitory effect being seen under conditions of anaerobiosis. Gene expression analyses performed by quantitative reverse transcriptase PCR showed that C11 led to the significant downregulation of rhl QS regulatory genes but also to the downregulation of both las QS regulatory genes and QS system-regulated virulence genes, rhlA and lasB. Furthermore, the activity of C11 in combination with antibiotics against P. aeruginosa biofilms was tested, and synergistic antibiofilm activity between C11 and ciprofloxacin, tobramycin, and colistin was obtained under both aerobic and anaerobic conditions. This study demonstrates that C11 may increase the efficacy of treatments for P. aeruginosa infections by increasing the susceptibility of biofilms to antibiotics and by attenuating the pathogenicity of the bacterium.}, } @article {pmid26711041, year = {2016}, author = {Huang, J and Wang, X and Cao, Q and Feng, F and Xu, X and Cai, X}, title = {ClpP participates in stress tolerance and negatively regulates biofilm formation in Haemophilus parasuis.}, journal = {Veterinary microbiology}, volume = {182}, number = {}, pages = {141-149}, doi = {10.1016/j.vetmic.2015.11.020}, pmid = {26711041}, issn = {1873-2542}, mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth & development ; Haemophilus Infections/genetics/microbiology/*veterinary ; Haemophilus parasuis/*genetics/pathogenicity ; Sequence Deletion ; Serine Endopeptidases/genetics ; Stress, Physiological/genetics ; Swine ; Swine Diseases/genetics/*microbiology ; }, abstract = {Haemophilus parasuis is generally considered a commensal organism in the upper respiratory tract of pigs, where it evades the host immune system and survives the challenging host environment. In response to various host stresses, H. parasuis strains can adapt to the adverse conditions. However, the specific bacterial factors that participate in this process are poorly understood. Here, we investigated the role of ClpP in H. parasuis virulent strain CF7066 by generating a clpP deletion mutant (ΔclpP), as well as a complemented strain C-clpP. Our findings supported that ClpP is essential for stress tolerance of H. parasuis, by the demonstrations that the ΔclpP mutant showed decreased resistance to heat, oxidation, and osmotic pressure. Notably, we observed increased autoagglutination and biofilm formation in the ΔclpP mutant and the amount of polysaccharides and extracellular proteins, which are the main components of biofilm, were much higher in the ΔclpP mutant than the wild-type strain. Real-time PCR demonstrated that the transcriptional regulators csrA and rpoD, and a possible biofilm repressor luxS were significantly downregulated upon clpP deletion. Together, these observations suggest that ClpP plays an essential role in stress tolerance, and negatively regulates biofilm formation in H. parasuis.}, } @article {pmid26710926, year = {2016}, author = {Myszka, K and Schmidt, MT and Białas, W and Olkowicz, M and Leja, K and Czaczyk, K}, title = {Role of gallic and p-coumaric acids in the AHL-dependent expression of flgA gene and in the process of biofilm formation in food-associated Pseudomonas fluorescens KM120.}, journal = {Journal of the science of food and agriculture}, volume = {96}, number = {12}, pages = {4037-4047}, doi = {10.1002/jsfa.7599}, pmid = {26710926}, issn = {1097-0010}, mesh = {4-Butyrolactone/*analogs & derivatives/biosynthesis ; Biofilms/drug effects/growth & development ; Coumaric Acids/*pharmacology ; Flagella/genetics ; Food Microbiology ; Gallic Acid/*pharmacology ; Gene Expression Regulation, Bacterial ; Humans ; Propionates ; Pseudomonas fluorescens/*drug effects/genetics ; }, abstract = {BACKGROUND: In the process of Pseudomonas fluorescens biofilm formation, N-acyl-l-homoserine lactone (AHL)-mediated flagella synthesis plays a key role. Inhibition of AHL production may attenuate P. fluorescens biofilm on solid surfaces. This work validated the anti-biofilm properties of p-coumaric and gallic acids via the ability of phenolics to suppress AHL synthesis in P. fluorescens KM120. The dependence between synthesis of AHL molecules, expression of flagella gene (flgA) and the ability of biofilm formation by P. fluorescens KM120 on a stainless steel surface (type 304L) was also investigated.

RESULTS: Research was carried out in a purpose-built flow cell device. Limitations on AHL synthesis in P. fluorescens KM120 were observed at concentrations of 120 and 240 µmol L(-1) of phenolic acids in medium. At such levels of gallic and p-coumaric acids the ability of P. fluorescens KM120 to synthesize 3-oxo-C6-homoserine lactone (HSL) was not observed. These concentrations caused decreased expression of flgA gene in P. fluorescens KM120. The changes in expression of AHL-dependent flgA gene significantly decreased the rate of microorganism colonization on the stainless steel surface.

CONCLUSION: Phenolic acids are able to inhibit biofilm formation. The results obtained in the work may help to develop alternative techniques for anti-biofilm treatment in the food industry. © 2015 Society of Chemical Industry.}, } @article {pmid26709923, year = {2015}, author = {Schkolnik, G and Schmidt, M and Mazza, MG and Harnisch, F and Musat, N}, title = {In Situ Analysis of a Silver Nanoparticle-Precipitating Shewanella Biofilm by Surface Enhanced Confocal Raman Microscopy.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0145871}, pmid = {26709923}, issn = {1932-6203}, mesh = {*Biofilms/growth & development ; Chemical Precipitation ; Cytochromes/metabolism ; Flavins/metabolism ; Metal Nanoparticles ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Oxidation-Reduction ; Phosphates/metabolism ; Polysaccharides, Bacterial/metabolism ; Shewanella/*physiology/ultrastructure ; Silver ; Spectrum Analysis, Raman ; Surface Properties ; }, abstract = {Shewanella oneidensis MR-1 is an electroactive bacterium, capable of reducing extracellular insoluble electron acceptors, making it important for both nutrient cycling in nature and microbial electrochemical technologies, such as microbial fuel cells and microbial electrosynthesis. When allowed to anaerobically colonize an Ag/AgCl solid interface, S. oneidensis has precipitated silver nanoparticles (AgNp), thus providing the means for a surface enhanced confocal Raman microscopy (SECRaM) investigation of its biofilm. The result is the in-situ chemical mapping of the biofilm as it developed over time, where the distribution of cytochromes, reduced and oxidized flavins, polysaccharides and phosphate in the undisturbed biofilm is monitored. Utilizing AgNp bio-produced by the bacteria colonizing the Ag/AgCl interface, we could perform SECRaM while avoiding the use of a patterned or roughened support or the introduction of noble metal salts and reducing agents. This new method will allow a spatially and temporally resolved chemical investigation not only of Shewanella biofilms at an insoluble electron acceptor, but also of other noble metal nanoparticle-precipitating bacteria in laboratory cultures or in complex microbial communities in their natural habitats.}, } @article {pmid26708984, year = {2016}, author = {Ramírez-Mata, A and López-Lara, LI and Xiqui-Vázquez, ML and Jijón-Moreno, S and Romero-Osorio, A and Baca, BE}, title = {The cyclic-di-GMP diguanylate cyclase CdgA has a role in biofilm formation and exopolysaccharide production in Azospirillum brasilense.}, journal = {Research in microbiology}, volume = {167}, number = {3}, pages = {190-201}, doi = {10.1016/j.resmic.2015.12.004}, pmid = {26708984}, issn = {1769-7123}, mesh = {Azospirillum brasilense/*enzymology/genetics/*physiology ; Bacteriological Techniques ; Biofilms/*growth & development ; Coenzymes/metabolism ; Cyclic GMP/*analogs & derivatives/metabolism ; Escherichia coli Proteins/isolation & purification/*metabolism ; Flavin-Adenine Dinucleotide/metabolism ; Guanosine Triphosphate/metabolism ; Magnesium/metabolism ; Microscopy, Confocal ; Phosphorus-Oxygen Lyases/isolation & purification/*metabolism ; Polysaccharides, Bacterial/*biosynthesis ; Staining and Labeling ; }, abstract = {In bacteria, proteins containing GGDEF domains are involved in production of the second messenger c-di-GMP. Here we report that the cdgA gene encoding diguanylate cyclase A (CdgA) is involved in biofilm formation and exopolysaccharide (EPS) production in Azospirillum brasilense Sp7. Biofilm quantification using crystal violet staining revealed that inactivation of cdgA decreased biofilm formation. In addition, confocal laser scanning microscopy analysis of green-fluorescent protein-labeled bacteria showed that, during static growth, the biofilms had differential levels of development: bacteria harboring a cdgA mutation exhibited biofilms with considerably reduced thickness compared with those of the wild-type Sp7 strain. Moreover, DNA-specific staining and treatment with DNase I, and epifluorescence studies demonstrated that extracellular DNA and EPS are components of the biofilm matrix in Azospirillum. After expression and purification of the CdgA protein, diguanylate cyclase activity was detected. The enzymatic activity of CdgA-producing cyclic c-di-GMP was determined using GTP as a substrate and flavin adenine dinucleotide (FAD(+)) and Mg(2)(+) as cofactors. Together, our results revealed that A. brasilense possesses a functional c-di-GMP biosynthesis pathway.}, } @article {pmid26708295, year = {2016}, author = {Zekker, I and Rikmann, E and Mandel, A and Kroon, K and Seiman, A and Mihkelson, J and Tenno, T and Tenno, T}, title = {Step-wise temperature decreasing cultivates a biofilm with high nitrogen removal rates at 9°C in short-term anammox biofilm tests.}, journal = {Environmental technology}, volume = {37}, number = {15}, pages = {1933-1946}, doi = {10.1080/09593330.2015.1135995}, pmid = {26708295}, issn = {1479-487X}, mesh = {Ammonium Compounds/chemistry/*metabolism ; *Biofilms ; *Bioreactors ; Nitrogen/analysis/*isolation & purification/*metabolism ; Temperature ; Wastewater/chemistry ; Water Purification ; }, abstract = {The anaerobic ammonium oxidation (anammox) and nitritation-anammox (deammonification) processes are widely used for N-rich wastewater treatment. When deammonification applications move towards low temperature applications (mainstream wastewater has low temperature), temperature effect has to be studied. In current research, in a deammonification moving bed biofilm reactor a maximum total nitrogen removal rate (TNRR) of 1.5 g N m(-2)d(-1) (0.6 kg N m(-3)d(-1)) was achieved. Temperature was gradually lowered by 0.5°C per week, and a similar TNRR was sustained at 15°C during biofilm cultivation. Statistical analysis confirmed that a temperature decrease from 20°C down to 15° did not cause instabilities. Instead, TNRR rose and treatment efficiency remained stable at lower temperatures as well. Quantitative polymerase chain reaction analyses showed an increase in Candidatus Brocadia quantities from 5 × 10(3) to 1 × 10(7) anammox gene copies g(-1) total suspended solids (TSS) despite temperature lowered to 15°C. Fluctuations in TNRR were rather related to changes in influent [Formula: see text] concentration. To study the short-term effect of temperature on the TNRR, a series of batch-scale experiments were performed which showed sufficient TNRRs even at 9-15°C (1.24-3.43 mg N g(-1)TSS h(-1), respectively) with anammox temperature constants (Q10) ranging 1.3-1.6. Experiments showed that a biofilm adapted to 15°C can perform N-removal most sufficiently at temperatures down to 9°C as compared with biofilm adapted to higher temperature. After biomass was adapted to 15°C, the decrease in TNRR in batch tests at 9°C was lower (15-20%) than that for biomass adapted to 17-18°C.}, } @article {pmid26707733, year = {2016}, author = {Cheng, L and House, MW and Weiss, WJ and Banks, MK}, title = {Monitoring sulfide-oxidizing biofilm activity on cement surfaces using non-invasive self-referencing microsensors.}, journal = {Water research}, volume = {89}, number = {}, pages = {321-329}, doi = {10.1016/j.watres.2015.11.066}, pmid = {26707733}, issn = {1879-2448}, mesh = {Bacteria/*growth & development/*metabolism ; Biofilms/*growth & development ; Biosensing Techniques ; Calcium/metabolism ; Construction Materials/*microbiology ; Corrosion ; Halothiobacillus ; *Oxidation-Reduction ; Oxygen/metabolism ; Sulfides/*chemistry ; Water Microbiology ; }, abstract = {Microbially influenced corrosion (MIC) in concrete results in significant cost for infrastructure maintenance. Prior studies have employed molecular techniques to identify microbial community species in corroded concrete, but failed to explore bacterial activity and functionality during deterioration. In this study, biofilms of different sulfur-oxidizing bacteria compositions were developed on the surface of cement paste samples to simulate the natural ecological succession of microbial communities during MIC processes. Noninvasive, self-referencing (SR) microsensors were used to quantify real time changes of oxygen, hydrogen ion and calcium ion flux for the biofilm to provide more information about bacterial behavior during deterioration. Results showed higher transport rates in oxygen consumption, and hydrogen ion at 4 weeks than 2 weeks, indicating increased bacterial activity over time. Samples with five species biofilm had the highest hydrogen ion and calcium ion transport rates, confirming attribution of acidophilic sulfur-oxidizing microorganisms (ASOM). Differences in transport rates between three species samples and two species samples confirmed the diversity between Thiomonas intermedia and Starkeya novella. The limitations of SR sensors in corrosion application could be improved in future studies when combined with molecular techniques to identify the roles of major bacterial species in the deterioration process.}, } @article {pmid26707697, year = {2016}, author = {Sun, P and Hui, C and Wang, S and Wan, L and Zhang, X and Zhao, Y}, title = {Bacillus amyloliquefaciens biofilm as a novel biosorbent for the removal of crystal violet from solution.}, journal = {Colloids and surfaces. B, Biointerfaces}, volume = {139}, number = {}, pages = {164-170}, doi = {10.1016/j.colsurfb.2015.12.014}, pmid = {26707697}, issn = {1873-4367}, mesh = {Adsorption ; Bacillus/*chemistry/physiology ; Bacterial Proteins/chemistry ; *Biofilms ; Diffusion ; Gentian Violet/*isolation & purification ; Humans ; Hydrogen-Ion Concentration ; Kinetics ; Polysaccharides, Bacterial/chemistry ; Thermodynamics ; Wastewater/*chemistry ; Water Pollutants, Chemical/*isolation & purification ; Water Purification/*methods ; }, abstract = {Bacillus amyloliquefaciens biofilm shows promise for use in the control of soil-borne pathogens; however, it has never been used to treat dye-polluted wastewaters. Here, we propose the novel idea of using B. amyloliquefaciens biofilm for the adsorption of crystal violet (CV) from liquids. The relative contents of three main elements (C1s, O1s, and N1s) in the biofilm were 65.55%, 21.21%, and 13.24%, respectively. The results of Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy revealed that the biofilm contained β-type heteropolysaccharide and proteins. The ruggedness of the biofilm surface due to embedded bacterial cells suggested potential adsorption sites for CV molecules. The maximum capacity for CV adsorption was 582.41mg/g, which is the largest value reported to date for any CV adsorbent. Blueshift occurred in the FTIR spectrum of CV-loaded biofilm as compared to that of virgin biofilm, confirming a physical adsorption process. We found that CV adsorption by biofilm was complex and resulted from intraparticle diffusion as well as surface adsorption. Our data also suggested that the process is exothermal and spontaneous, with micropore diffusion as the rate-limiting step. These findings provide a basis for using B. amyloliquefaciens biofilm as an efficient adsorbent for treating CV-polluted wastewaters.}, } @article {pmid26706821, year = {2016}, author = {Padhi, A and Naik, SK and Sengupta, S and Ganguli, G and Sonawane, A}, title = {Expression of Mycobacterium tuberculosis NLPC/p60 family protein Rv0024 induce biofilm formation and resistance against cell wall acting anti-tuberculosis drugs in Mycobacterium smegmatis.}, journal = {Microbes and infection}, volume = {18}, number = {4}, pages = {224-236}, doi = {10.1016/j.micinf.2015.11.007}, pmid = {26706821}, issn = {1769-714X}, mesh = {Amidohydrolases/genetics/*metabolism ; Animals ; Antitubercular Agents/*pharmacology ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; *Drug Resistance, Bacterial ; Endocytosis ; Gene Expression ; Lipoproteins/genetics/*metabolism ; Mice ; Microbial Viability ; Microscopy, Confocal ; Microscopy, Electron, Transmission ; Mycobacterium smegmatis/*drug effects/genetics/*physiology ; Mycobacterium tuberculosis/*genetics ; Peptidoglycan/genetics/*metabolism ; Recombinant Proteins/genetics/metabolism ; }, abstract = {Bacterial species are capable of living as biofilm and/or planktonic forms. Role of biofilms in the pathogenesis of several human pathogens is well established. However, in case of Mycobacterium tuberculosis (Mtb) infection the role of biofilms and the genetic requirements for biofilm formation remains largely unknown. We herein report that ectopic expression of Mtb Rv0024, encoding a putative peptidoglycan amidase, in non-pathogenic Mycobacterium smegmatis(Msm) strain (MsmRv0024) confer at least 10-fold increase in resistance against two prominent anti-tuberculosis drugs isoniazid and pyrazinamide. We further report that the development of resistance was due to significant increase in biofilm formation by Rv0024. Transmission electron microscopy revealed differences in cell surface architecture of MsmRv0024 when compared with Msm wild-type (WT) and vector control Msm pSMT3 (pSMT3) strains and this aggregation pattern was due to increased cell wall hydrophobicity, as determined by Bacterial adhesion to hydrocarbons assay (BATH). Confocal microscopy study showed increased adherence of MsmRv0024 bacteria to lung epithelial cells as compared to pSMT3 strain. However, infection studies showed no differences in host cell invasion and intracellular survival in mouse macrophages. We envision that Rv0024 may play a critical role in initial infection process, adherence to host cells and drug resistance. Thus, Rv0024 may be considered as a potential drug target for the treatment of tuberculosis.}, } @article {pmid26706536, year = {2016}, author = {Pérez-Díaz, M and Alvarado-Gomez, E and Magaña-Aquino, M and Sánchez-Sánchez, R and Velasquillo, C and Gonzalez, C and Ganem-Rondero, A and Martínez-Castañon, G and Zavala-Alonso, N and Martinez-Gutierrez, F}, title = {Anti-biofilm activity of chitosan gels formulated with silver nanoparticles and their cytotoxic effect on human fibroblasts.}, journal = {Materials science & engineering. C, Materials for biological applications}, volume = {60}, number = {}, pages = {317-323}, doi = {10.1016/j.msec.2015.11.036}, pmid = {26706536}, issn = {1873-0191}, mesh = {Biofilms/drug effects ; Cells, Cultured ; Chitosan/*chemistry ; Fibroblasts/drug effects ; Gels ; Humans ; Metal Nanoparticles/*chemistry ; Silver/*chemistry/toxicity ; }, abstract = {The development of multi-species biofilms in chronic wounds is a serious health problem that primarily generates strong resistance mechanisms to antimicrobial therapy. The use of silver nanoparticles (AgNPs) as a broad-spectrum antimicrobial agent has been studied previously. However, their cytotoxic effects limit its use within the medical area. The purpose of this study was to evaluate the anti-biofilm capacity of chitosan gel formulations loaded with AgNPs, using silver sulfadiazine (SSD) as a standard treatment, on strains of clinical isolates, as well as their cytotoxic effect on human primary fibroblasts. Multi-species biofilm of Staphylococcus aureus oxacillin resistant (MRSA) and Pseudomonas aeruginosa obtained from a patient with chronic wound infection were carried out using a standard Drip Flow Reactor (DFR) under conditions that mimic the flow of nutrients in the human skin. Anti-biofilm activity of chitosan gels and SSD showed a log-reduction of 6.0 for MRSA when chitosan gel with AgNPs at a concentration of 100 ppm was used, however it was necessary to increase the concentration of the chitosan gel with AgNPs to 1000 ppm to get a log-reduction of 3.3, while the SSD showed a total reduction of both bacteria in comparison with the negative control. The biocompatibility evaluation on primary fibroblasts showed better results when the chitosan gels with AgNPs were tested even in the high concentration, in contrast with SSD, which killed all the primary fibroblasts. In conclusion, chitosan gel formulations loaded with AgNPs effectively prevent the formation of biofilm and kill bacteria in established biofilm, which suggest that chitosan gels with AgNPs could be used for prevention and treatment of infections in chronic wounds. The statistic significance of the biocompatibility of chitosan gel formulations loaded with AgNPs represents an advance; however further research and development are necessary to translate this technology into therapeutic and preventive strategies.}, } @article {pmid26705856, year = {2017}, author = {Tawakoli, PN and Ragnarsson, KT and Rechenberg, DK and Mohn, D and Zehnder, M}, title = {Effect of endodontic irrigants on biofilm matrix polysaccharides.}, journal = {International endodontic journal}, volume = {50}, number = {2}, pages = {153-160}, doi = {10.1111/iej.12604}, pmid = {26705856}, issn = {1365-2591}, mesh = {Biofilms/*drug effects ; Endodontics ; Root Canal Irrigants ; Sodium Hypochlorite/pharmacology ; }, abstract = {AIM: To specifically investigate the effect of endodontic irrigants at their clinical concentration on matrix polysaccharides of cultured biofilms.

METHODOLOGY: Saccharolytic effects of 3% H2 O2 , 2% chlorhexidine (CHX), 17% EDTA, 5% NaOCl and 0.9% saline (control) were tested using agarose (α 1-3 and β 1-4 glycosidic bonds) blocks (n = 3) in a weight assay. The irrigants were also applied to three-species biofilms (Streptococcus mutans UAB 159, Streptococcus oralis OMZ 607 and Actinomyces oris OMZ 745) grown anaerobically on hydroxyapatite discs (n = 6). Glycoconjugates in the matrix and total bacterial cell volumes were determined using combined Concanavalin A-/Syto 59-staining and confocal laser-scanning microscopy. Volumes of each scanned area (triplicates/sample) were calculated using Imaris software. Data were compared between groups using one-way anova/Tukey HSD, α = 0.05.

RESULTS: The weight assay revealed that NaOCl was the only irrigant under investigation capable of dissolving the agarose blocks. NaOCl eradicated stainable matrix and bacteria in cultured biofilms after 1 min of exposure (P < 0.05 compared to all groups, volumes in means ± standard deviation, 10[-3]  mm[3] per 0.6 mm[2] disc; NaOCl matrix: 0.10 ± 0.08, bacteria: 0.03 ± 0.06; saline control matrix: 4.01 ± 1.14, bacteria: 11.56 ± 3.02). EDTA also appeared to have some effect on the biofilm matrix (EDTA matrix: 1.90 ± 0.33, bacteria: 9.26 ± 2.21), whilst H2 O2 and CHX merely reduced bacterial cell volumes.

CONCLUSION: Sodium hypochlorite can break glycosidic bonds. It dissolves glycoconjugates in the biofilm matrix. It also lyses bacterial cells.}, } @article {pmid26702975, year = {2015}, author = {Mielcarek, A and Rodziewicz, J and Janczukowicz, W and Thornton, AJ and Jóźwiak, T and Szymczyk, P}, title = {Effect of the C:N:P ratio on the denitrifying dephosphatation in a sequencing batch biofilm reactor (SBBR).}, journal = {Journal of environmental sciences (China)}, volume = {38}, number = {}, pages = {119-125}, doi = {10.1016/j.jes.2015.05.018}, pmid = {26702975}, issn = {1001-0742}, mesh = {*Biofilms ; Bioreactors/*microbiology ; Carbon/*chemistry ; Nitrogen/*chemistry ; Phosphorus/*chemistry ; }, abstract = {A series of investigations were conducted using sequencing batch biofilm reactor (SBBR) to explore the influence of C:N:P ratio on biological dephosphatation including the denitrifying dephosphatation and the denitrification process. Biomass in the reactor occurred mainly in the form of a biofilm attached to completely submerged disks. Acetic acid was used as the source of organic carbon. C:N:P ratios have had a significant effect on the profiles of phosphate release and phosphate uptake and nitrogen removal. The highest rates of phosphate release and phosphate uptake were recorded at the C:N:P ratio of 140:70:7. The C:N ratio of 2.5:1 ensured complete denitrification. The highest rate of denitrification was achieved at the C:N:P ratio of 140:35:7. The increase of nitrogen load caused an increase in phosphates removal until a ratio C:N:P of 140:140:7. Bacteria of the biofilm exposed to alternate conditions of mixing and aeration exhibited enhanced intracellular accumulation of polyphosphates. Also, the structure of the biofilm encouraged anaerobic-aerobic as well as anoxic-anaerobic and absolutely anaerobic conditions in a SBBR. These heterogeneous conditions in the presence of nitrates may be a significant factor determining the promotion of denitrifying polyphosphate accumulating organism (DNPAO) development.}, } @article {pmid26702917, year = {2016}, author = {Kucharíková, S and Gerits, E and De Brucker, K and Braem, A and Ceh, K and Majdič, G and Španič, T and Pogorevc, E and Verstraeten, N and Tournu, H and Delattin, N and Impellizzeri, F and Erdtmann, M and Krona, A and Lövenklev, M and Knezevic, M and Fröhlich, M and Vleugels, J and Fauvart, M and de Silva, WJ and Vandamme, K and Garcia-Forgas, J and Cammue, BP and Michiels, J and Van Dijck, P and Thevissen, K}, title = {Covalent immobilization of antimicrobial agents on titanium prevents Staphylococcus aureus and Candida albicans colonization and biofilm formation.}, journal = {The Journal of antimicrobial chemotherapy}, volume = {71}, number = {4}, pages = {936-945}, doi = {10.1093/jac/dkv437}, pmid = {26702917}, issn = {1460-2091}, mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Antifungal Agents/pharmacology ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Caspofungin ; Cell Line ; Echinocandins/pharmacology ; Female ; Humans ; Lipopeptides/pharmacology ; Mice ; Mice, Inbred BALB C ; Osseointegration ; Prostheses and Implants/microbiology ; Staphylococcus aureus/*drug effects/physiology ; Titanium/*pharmacology ; Vancomycin/pharmacology ; }, abstract = {OBJECTIVES: Biofilm-associated implant infections represent a serious public health problem. Covalent immobilization of antimicrobial agents on titanium (Ti), thereby inhibiting biofilm formation of microbial pathogens, is a solution to this problem.

METHODS: Vancomycin (VAN) and caspofungin (CAS) were covalently bound on Ti substrates using an improved processing technique adapted to large-scale coating of implants. Resistance of the VAN-coated Ti (VAN-Ti) and CAS-coated Ti (CAS-Ti) substrates against in vitro biofilm formation of the bacterium Staphylococcus aureus and the fungal pathogen Candida albicans was determined by plate counting and visualized by confocal laser scanning microscopy. The efficacy of the coated Ti substrates was also tested in vivo using an adapted biomaterial-associated murine infection model in which control-Ti, VAN-Ti or CAS-Ti substrates were implanted subcutaneously and subsequently challenged with the respective pathogens. The osseointegration potential of VAN-Ti and CAS-Ti was examined in vitro using human bone marrow-derived stromal cells, and for VAN-Ti also in a rat osseointegration model.

RESULTS: In vitro biofilm formation of S. aureus and C. albicans on VAN-Ti and CAS-Ti substrates, respectively, was significantly reduced compared with biofilm formation on control-Ti. In vivo, we observed over 99.9% reduction in biofilm formation of S. aureus on VAN-Ti substrates and 89% reduction in biofilm formation of C. albicans on CAS-Ti substrates, compared with control-Ti substrates. The coated substrates supported osseointegration in vitro and in vivo.

CONCLUSIONS: These data demonstrate the clinical potential of covalently bound VAN and CAS on Ti to reduce microbial biofilm formation without jeopardizing osseointegration.}, } @article {pmid26700108, year = {2016}, author = {Dang, H and Lovell, CR}, title = {Microbial Surface Colonization and Biofilm Development in Marine Environments.}, journal = {Microbiology and molecular biology reviews : MMBR}, volume = {80}, number = {1}, pages = {91-138}, pmid = {26700108}, issn = {1098-5557}, mesh = {Aquatic Organisms/*genetics/metabolism ; Archaea/*genetics/metabolism ; Bacteria/*genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth & development ; Biological Transport ; Carbon Cycle/genetics ; Chemotaxis/genetics ; Ecosystem ; *Gene Expression Regulation, Bacterial ; Microbial Consortia/genetics ; Microbial Interactions/genetics ; Quorum Sensing/genetics ; Seawater/microbiology ; }, abstract = {Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration.}, } @article {pmid26697862, year = {2016}, author = {Zhang, L and Zhao, J and Cui, N and Dai, Y and Kong, L and Wu, J and Cheng, S}, title = {Enhancing the water purification efficiency of a floating treatment wetland using a biofilm carrier.}, journal = {Environmental science and pollution research international}, volume = {23}, number = {8}, pages = {7437-7443}, pmid = {26697862}, issn = {1614-7499}, mesh = {Adsorption ; Ammonia/analysis/chemistry/metabolism ; Biodegradation, Environmental ; *Biofilms ; Phosphates/analysis/chemistry/metabolism ; Phosphorus/analysis/chemistry/metabolism ; Plants/chemistry/*metabolism ; Waste Disposal, Fluid/*methods ; Water Pollutants, Chemical/analysis/chemistry/*metabolism ; Water Purification/*methods ; *Wetlands ; }, abstract = {Floating treatment wetlands (FTWs) and biofilm carriers are widely used in water purification. The objective of the present work was to explore whether and to what extent an FTW integrated with plants and biofilm carriers (FTW-I) could enhance the nutrient removal efficiency. Significantly higher removal rates of ammonia nitrogen (85.2 %), total phosphorus (82.7 %), and orthophosphate (82.5 %) were observed in the FTW-I treatment relative to the FTW with plants (FTW-P; 80.0, 78.5, and 77.6 %, respectively) and the FTW with biofilm carriers (FTW-B; 56.7, 12.9, and 13.4 %, respectively) (p < 0.05). The mass balance results indicated that plant uptake was the main pathway for N and P removal (accounting for 58.1 and 91.4 %, respectively) in FTW-I, in which only 1.2 % of the N and 5.7 % of the P was deposited on the bottom of the tank. In addition, the plants translocated 43.9 and 80.2 % of the N and P in the water and 83.5 and 88.3 % of the absorbed N and P, respectively, into their aboveground tissues. The combination of an FTW and biofilm carriers can improve the efficiency of water purification, and nutrients can be rapidly removed from the system by harvesting the aboveground plant tissues.}, } @article {pmid26697553, year = {2016}, author = {Pini-Prato, G and Magnani, C and Rotundo, R}, title = {Treatment of Acute Periodontal Abscesses Using the Biofilm Decontamination Approach: A Case Report Study.}, journal = {The International journal of periodontics & restorative dentistry}, volume = {36}, number = {1}, pages = {55-63}, doi = {10.11607/prd.2557}, pmid = {26697553}, issn = {1945-3388}, mesh = {Acute Disease ; Adult ; Aged ; Biofilms/*drug effects ; Decontamination/*methods ; Female ; Humans ; Male ; Middle Aged ; Pain Measurement ; Periodontal Abscess/*drug therapy/*microbiology ; Phenol/*pharmacology ; Sulfonic Acids/*pharmacology ; Sulfuric Acids/*pharmacology ; Surveys and Questionnaires ; }, abstract = {The aim of this preliminary study was to show the treatment effect of the biofilm decontamination approach on acute periodontal abscesses. Clinical cases showing acute periodontitis were treated using an oral tissue decontaminant material that contains a concentrated aqueous mixture of hydroxybenzenesulfonic and hydroxymethoxybenzene acids and sulfuric acid. The material was positioned into the pocket on the root surface and left in the site for 30 seconds. No instrumentation was performed before the treatment. No systemic or local antibiotics were used in any of the cases. A questionnaire was used for each patient to record the pain/discomfort felt when the material was administered. All of the treated cases healed well and very rapidly. The infections were quickly resolved without complications, and the pockets associated with marginal tissue recession were also reduced. The momentary pain upon introduction of the material was generally well tolerated in the nonsurgically treated cases, and it completely disappeared after a few seconds. The biofilm decontamination approach seems to be a very promising technique for the treatment of acute periodontal abscess. The local application of this material avoids the use of systemic or local antibiotics.}, } @article {pmid26697145, year = {2015}, author = {Frough Reyhani, M and Rahimi, S and Fathi, Z and Shakouie, S and Salem Milani, A and Soroush Barhaghi, MH and Shokri, J}, title = {Evaluation of Antimicrobial Effects of Different Concentrations of Triple Antibiotic Paste on Mature Biofilm of Enterococcus faecalis.}, journal = {Journal of dental research, dental clinics, dental prospects}, volume = {9}, number = {3}, pages = {138-143}, pmid = {26697145}, issn = {2008-210X}, abstract = {Background and aims. Triple antibiotic paste (TAP) is widely used in endodontics for root canal disinfection, particularly in regenerative procedures. The aim of this in vitro study was to evaluate the antimicrobial effects of different concentrations of TAP at 1-, 2-, 3-, and 4-week intervals on mature Enterococcus faecalis biofilm. Materials and methods. A total of 287 extracted one-rooted human central incisors were infected with E. faecalis ATCC 29212 after removing the crown and preparation. The root canal space was filled with one of the 0.01-, 0.1-, 1-, 10-, 100-, and 1000-mg/mL concentrations of TAP or normal saline (control). The root canal dentin was sampled after 1, 2, 3, and 4 weeks. The dentinal shavings were cultured on Mueller-Hinton agar plates after serial dilutions. The classic colony-forming unit (CFU) counting technique was used to determine remaining bacterial counts. Data were analyzed by using the two-way ANOVA, post hoc Tukey tests and one-way ANOVA (P<0.05). Results. TAP completely eliminated E. faecalis biofilms at all the intervals at concentrations of 1000, 100, and 10 mg/mL, whereas 1-, 0.1-, and 0.01-mg/mL TAP resulted in significant reduction of CFU means compared with the control group. There were no statistically significant differences between the four time intervals. Conclusion. Use of lower concentrations of TAP at short term could eradicate E. faecalis biofilm and decrease high-concentration side effects.}, } @article {pmid26696973, year = {2015}, author = {Arnal, L and Grunert, T and Cattelan, N and de Gouw, D and Villalba, MI and Serra, DO and Mooi, FR and Ehling-Schulz, M and Yantorno, OM}, title = {Bordetella pertussis Isolates from Argentinean Whooping Cough Patients Display Enhanced Biofilm Formation Capacity Compared to Tohama I Reference Strain.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1352}, pmid = {26696973}, issn = {1664-302X}, abstract = {Pertussis is a highly contagious disease mainly caused by Bordetella pertussis. Despite the massive use of vaccines, since the 1950s the disease has become re-emergent in 2000 with a shift in incidence from infants to adolescents and adults. Clearly, the efficacy of current cellular or acellular vaccines, formulated from bacteria grown in stirred bioreactors is limited, presenting a challenge for future vaccine development. For gaining insights into the role of B. pertussis biofilm development for host colonization and persistence within the host, we examined the biofilm forming capacity of eight argentinean clinical isolates recovered from 2001 to 2007. All clinical isolates showed an enhanced potential for biofilm formation compared to the reference strain Tohama I. We further selected the clinical isolate B. pertussis 2723, exhibiting the highest biofilm biomass production, for quantitative proteomic profiling by means of two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry, which was accompanied by targeted transcriptional analysis. Results revealed an elevated expression of several virulence factors, including adhesins involved in biofilm development. In addition, we observed a higher expression of energy metabolism enzymes in the clinical isolate compared to the Tohama I strain. Furthermore, all clinical isolates carried a polymorphism in the bvgS gene. This mutation was associated to an increased sensitivity to modulation and a faster rate of adhesion to abiotic surfaces. Thus, the phenotypic biofilm characteristics shown by the clinical isolates might represent an important, hitherto underestimated, adaptive strategy for host colonization and long time persistence within the host.}, } @article {pmid26696962, year = {2015}, author = {Papa, R and Selan, L and Parrilli, E and Tilotta, M and Sannino, F and Feller, G and Tutino, ML and Artini, M}, title = {Anti-Biofilm Activities from Marine Cold Adapted Bacteria Against Staphylococci and Pseudomonas aeruginosa.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1333}, pmid = {26696962}, issn = {1664-302X}, abstract = {Microbial biofilms have great negative impacts on the world's economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules. The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules and to test their use in combination with conventional antibiotics.}, } @article {pmid26694756, year = {2015}, author = {Shin, HC and Ju, DH and Jeon, BS and Choi, O and Kim, HW and Um, Y and Lee, DH and Sang, BI}, title = {Analysis of the Microbial Community in an Acidic Hollow-Fiber Membrane Biofilm Reactor (Hf-MBfR) Used for the Biological Conversion of Carbon Dioxide to Methane.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0144999}, pmid = {26694756}, issn = {1932-6203}, mesh = {Acetates/*chemistry ; Biofilms ; Bioreactors/*microbiology ; Carbon Dioxide/*metabolism ; Clostridium/classification/genetics/isolation & purification ; Culture Media/chemistry ; DNA, Archaeal/analysis ; DNA, Bacterial/analysis ; DNA, Ribosomal/analysis ; Methane/*metabolism ; Methanobacterium/classification/genetics/*isolation & purification ; Phylogeny ; RNA, Ribosomal, 16S/analysis ; Sequence Analysis, RNA ; }, abstract = {Hydrogenotrophic methanogens can use gaseous substrates, such as H2 and CO2, in CH4 production. H2 gas is used to reduce CO2. We have successfully operated a hollow-fiber membrane biofilm reactor (Hf-MBfR) for stable and continuous CH4 production from CO2 and H2. CO2 and H2 were diffused into the culture medium through the membrane without bubble formation in the Hf-MBfR, which was operated at pH 4.5-5.5 over 70 days. Focusing on the presence of hydrogenotrophic methanogens, we analyzed the structure of the microbial community in the reactor. Denaturing gradient gel electrophoresis (DGGE) was conducted with bacterial and archaeal 16S rDNA primers. Real-time qPCR was used to track changes in the community composition of methanogens over the course of operation. Finally, the microbial community and its diversity at the time of maximum CH4 production were analyzed by pyrosequencing methods. Genus Methanobacterium, related to hydrogenotrophic methanogens, dominated the microbial community, but acetate consumption by bacteria, such as unclassified Clostridium sp., restricted the development of acetoclastic methanogens in the acidic CH4 production process. The results show that acidic operation of a CH4 production reactor without any pH adjustment inhibited acetogenic growth and enriched the hydrogenotrophic methanogens, decreasing the growth of acetoclastic methanogens.}, } @article {pmid26691764, year = {2015}, author = {Pierce, CG and Chaturvedi, AK and Lazzell, AL and Powell, AT and Saville, SP and McHardy, SF and Lopez-Ribot, JL}, title = {A Novel Small Molecule Inhibitor of Candida albicans Biofilm Formation, Filamentation and Virulence with Low Potential for the Development of Resistance.}, journal = {NPJ biofilms and microbiomes}, volume = {1}, number = {}, pages = {15012-}, pmid = {26691764}, issn = {2055-5008}, support = {G12 MD007591/MD/NIMHD NIH HHS/United States ; R01 AI063256/AI/NIAID NIH HHS/United States ; R01 DE023510/DE/NIDCR NIH HHS/United States ; R21 DE017294/DE/NIDCR NIH HHS/United States ; }, abstract = {BACKGROUND/OBJECTIVES: Candida albicans is the principal causative agent of candidiasis, the most common fungal infection in humans. Candidiasis represents the third-to-fourth most frequent nosocomial infection worldwide, as this normal commensal of humans causes opportunistic infections in an expanding population of immune- and medically-compromised patients. These infections are frequently associated with biofilm formation, which complicates treatment and contributes to unacceptably high mortality rates.

METHODS: To address the pressing need for new antifungals we have performed a high content screen of 20,000 small molecules in a chemical library (NOVACore™) to identify compounds that inhibit C. albicans biofilm formation, and conducted a series of follow-up studies to examine the in vitro and in vivo activity of the identified compounds.

RESULTS: The screen identified a novel series of diazaspiro-decane structural analogs which were largely represented among the bioactive compounds. Characterization of the leading compound from this series indicated that it inhibits processes associated with C. albicans virulence, most notably biofilm formation and filamentation, without having an effect on overall growth or eliciting resistance. This compound demonstrated in vivo activity in clinically-relevant murine models of both invasive and oral candidiasis and as such represents a promising lead for antifungal drug development. Furthermore, these results provide proof of concept for the implementation of anti-virulence approaches against C. albicans and other fungal infections that would be less likely to foster the emergence of resistance.}, } @article {pmid26691259, year = {2015}, author = {Anutrakunchai, C and Sermswan, RW and Wongratanacheewin, S and Puknun, A and Taweechaisupapong, S}, title = {Drug susceptibility and biofilm formation of Burkholderia pseudomallei in nutrient-limited condition.}, journal = {Tropical biomedicine}, volume = {32}, number = {2}, pages = {300-309}, pmid = {26691259}, issn = {2521-9855}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*growth & development ; Burkholderia pseudomallei/*drug effects/*physiology ; Culture Media/*chemistry ; Drug Tolerance ; Microbial Sensitivity Tests ; Microbial Viability/drug effects ; }, abstract = {Burkholderia pseudomallei is the causative agent of melioidosis, which can form biofilms and microcolonies in vivo and in vitro. One of the hallmark characteristics of the biofilm-forming bacteria is that they can be up to 1,000 times more resistant to antibiotics than their free-living counterpart. Bacteria also become highly tolerant to antibiotics when nutrients are limited. One of the most important causes of starvation induced tolerance in vivo is biofilm growth. However, the effect of nutritional stress on biofilm formation and drug tolerance of B. pseudomallei has never been reported. Therefore, this study aims to determine the effect of nutrient-limited and enriched conditions on drug susceptibility of B. pseudomallei in both planktonic and biofilm forms in vitro using broth microdilution method and Calgary biofilm device, respectively. The biofilm formation of B. pseudomallei in nutrient-limited and enriched conditions was also evaluated by a modified microtiter-plate test. Six isolates of ceftazidime (CAZ)-susceptible and four isolates of CAZ-resistant B. pseudomallei were used. The results showed that the minimum bactericidal concentrations of CAZ against B. pseudomallei in nutrient-limited condition were higher than those in enriched condition. The drug susceptibilities of B. pseudomallei biofilm in both enriched and nutrient-limited conditions were more tolerant than those of planktonic cells. Moreover, the quantification of biofilm formation by B. pseudomallei in nutrient-limited condition was significantly higher than that in enriched condition. These data indicate that nutrient-limited condition could induce biofilm formation and drug tolerance of B. pseudomallei.}, } @article {pmid26686120, year = {2016}, author = {Powell, LC and Khan, S and Chinga-Carrasco, G and Wright, CJ and Hill, KE and Thomas, DW}, title = {An investigation of Pseudomonas aeruginosa biofilm growth on novel nanocellulose fibre dressings.}, journal = {Carbohydrate polymers}, volume = {137}, number = {}, pages = {191-197}, doi = {10.1016/j.carbpol.2015.10.024}, pmid = {26686120}, issn = {1879-1344}, mesh = {Biofilms/*growth & development ; Cellulose/*chemistry ; Microscopy, Atomic Force ; Nanostructures/*chemistry ; Pseudomonas aeruginosa/*growth & development ; }, abstract = {Nanocellulose from wood is a novel biomaterial, which is highly fibrillated at the nanoscale. This affords the material a number of advantages, including self-assembly, biodegradability and the ability to absorb and retain moisture, which highlights its potential usefulness in clinical wound-dressing applications. In these in vitro studies, the wound pathogen Pseudomonas aeruginosa PAO1 was used to assess the ability of two nanocellulose materials to impair bacterial growth (<48 h). The two nanocelluloses had a relatively small fraction of residual fibres (<4%) and thus a large fraction of nanofibrils (widths <20 nm). Scanning electron microscopy and confocal laser scanning microscopy imaging demonstrated impaired biofilm growth on the nanocellulose films and increased cell death when compared to a commercial control wound dressing, Aquacel(®). Nanocellulose suspensions inhibited bacterial growth, whilst UV-vis spectrophotometry and laser profilometry also revealed the ability of nanocellulose to form smooth, translucent films. Atomic force microscopy studies of the surface properties of nanocellulose demonstrated that PAO1 exhibited markedly contrasting morphology when grown on the nanocellulose film surfaces compared to an Aquacel(®) control dressing (p<0.05). This study highlights the potential utility of these biodegradable materials, from a renewable source, for wound dressing applications in the prevention and treatment of biofilm development.}, } @article {pmid26684897, year = {2015}, author = {Rudney, JD and Jagtap, PD and Reilly, CS and Chen, R and Markowski, TW and Higgins, L and Johnson, JE and Griffin, TJ}, title = {Protein relative abundance patterns associated with sucrose-induced dysbiosis are conserved across taxonomically diverse oral microcosm biofilm models of dental caries.}, journal = {Microbiome}, volume = {3}, number = {}, pages = {69}, pmid = {26684897}, issn = {2049-2618}, support = {R01 DE017734/DE/NIDCR NIH HHS/United States ; R01 DE021366/DE/NIDCR NIH HHS/United States ; 5R01DE17734/DE/NIDCR NIH HHS/United States ; }, mesh = {Bacterial Proteins/*analysis ; Biofilms/drug effects/growth & development ; Biomarkers ; Dental Caries/etiology/*microbiology/prevention & control ; Dental Plaque/chemistry/*microbiology ; Dysbiosis/*chemically induced/metabolism/microbiology ; Glycolysis/drug effects ; Humans ; Microbial Consortia/drug effects/genetics/physiology ; Microbiota/drug effects/genetics/*physiology ; Proteins/*analysis ; Proteomics ; RNA, Ribosomal, 16S/genetics ; Saliva/microbiology ; Sucrose/administration & dosage/*pharmacology ; }, abstract = {BACKGROUND: The etiology of dental caries is multifactorial, but frequent consumption of free sugars, notably sucrose, appears to be a major factor driving the supragingival microbiota in the direction of dysbiosis. Recent 16S rRNA-based studies indicated that caries-associated communities were less diverse than healthy supragingival plaque but still displayed considerable taxonomic diversity between individuals. Metagenomic studies likewise have found that healthy oral sites from different people were broadly similar with respect to gene function, even though there was an extensive individual variation in their taxonomic profiles. That pattern may also extend to dysbiotic communities. In that case, shifts in community-wide protein relative abundance might provide better biomarkers of dysbiosis that can be achieved through taxonomy alone.

RESULTS: In this study, we used a paired oral microcosm biofilm model of dental caries to investigate differences in community composition and protein relative abundance in the presence and absence of sucrose. This approach provided large quantities of protein, which facilitated deep metaproteomic analysis. Community composition was evaluated using 16S rRNA sequencing and metaproteomic approaches. Although taxonomic diversity was reduced by sucrose pulsing, considerable inter-subject variation in community composition remained. By contrast, functional analysis using the SEED ontology found that sucrose induced changes in protein relative abundance patterns for pathways involving glycolysis, lactate production, aciduricity, and ammonia/glutamate metabolism that were conserved across taxonomically diverse dysbiotic oral microcosm biofilm communities.

CONCLUSIONS: Our findings support the concept of using function-based changes in protein relative abundance as indicators of dysbiosis. Our microcosm model cannot replicate all aspects of the oral environment, but the deep level of metaproteomic analysis it allows makes it suitable for discovering which proteins are most consistently abundant during dysbiosis. It then may be possible to define biomarkers that could be used to detect at-risk tooth surfaces before the development of overt carious lesions.}, } @article {pmid26682547, year = {2015}, author = {Walter, BM and Cartman, ST and Minton, NP and Butala, M and Rupnik, M}, title = {The SOS Response Master Regulator LexA Is Associated with Sporulation, Motility and Biofilm Formation in Clostridium difficile.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0144763}, pmid = {26682547}, issn = {1932-6203}, support = {G0601176/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/*genetics/*metabolism ; Bacterial Toxins/metabolism ; Biofilms/drug effects/*growth & development ; Cell Division ; Clostridioides difficile/drug effects/genetics/*physiology ; Enterotoxins/metabolism ; Gene Expression Regulation, Bacterial/drug effects ; Levofloxacin/pharmacology ; Mutation ; SOS Response, Genetics ; Serine Endopeptidases/*genetics/*metabolism ; Spores, Bacterial/drug effects/growth & development ; }, abstract = {The LexA regulated SOS network is a bacterial response to DNA damage of metabolic or environmental origin. In Clostridium difficile, a nosocomial pathogen causing a range of intestinal diseases, the in-silico deduced LexA network included the core SOS genes involved in the DNA repair and genes involved in various other biological functions that vary among different ribotypes. Here we describe the construction and characterization of a lexA ClosTron mutant in C. difficile R20291 strain. The mutation of lexA caused inhibition of cell division resulting in a filamentous phenotype. The lexA mutant also showed decreased sporulation, a reduction in swimming motility, greater sensitivity to metronidazole, and increased biofilm formation. Changes in the regulation of toxin A, but not toxin B, were observed in the lexA mutant in the presence of sub-inhibitory concentrations of levofloxacin. C. difficile LexA is, therefore, not only a regulator of DNA damage but also controls many biological functions associated with virulence.}, } @article {pmid26682456, year = {2015}, author = {Naik, K and Srivastava, P and Deshmukh, K and Monsoor, MS and Kowshik, M}, title = {Nanomaterial-Based Approaches for Prevention of Biofilm-Associated Infections on Medical Devices and Implants.}, journal = {Journal of nanoscience and nanotechnology}, volume = {15}, number = {12}, pages = {10108-10119}, doi = {10.1166/jnn.2015.11688}, pmid = {26682456}, issn = {1533-4880}, mesh = {Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Humans ; Nanostructures/*chemistry ; Prostheses and Implants ; Prosthesis-Related Infections/*prevention & control ; }, abstract = {Biofilm formation is a major problem in medical device-related infections leading to failure of implant-based therapies. Though various conventional approaches to counter biofilm formation like physical and/or mechanical removal, chemical removal, and the use of antimicrobials exist, they fail due to increased resistance of biofilms. This review discusses various nanomaterial-based approaches such as the use of metallic and metal oxide nanoparticles- and polymer-based nanocomposites, which are currently being developed for prevention and treatment of biofilms. Nanoparticles of transition metals and their oxides are toxic to microorganisms and exhibit their toxicity through the generation of reactive oxygen species at concentrations that are non-toxic to eukaryotic cells. Other approaches include the entrapment of bioactive agents in polymer/ceramic nanoparticles, for enhanced anti-biofilm activity due to the synergistic effect between them. These nanomaterial-based approaches could play an important role in control and eradication of biofilm related infections and complications associated with medical devices and implants.}, } @article {pmid26679653, year = {2015}, author = {Wu, LJ and Wang, B and Liao, QP and Zhang, R}, title = {[Confocal laser scanning electron microscopy for assessment of vaginal Lactobacillus crispatus biofilm].}, journal = {Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences}, volume = {47}, number = {6}, pages = {933-938}, pmid = {26679653}, issn = {1671-167X}, mesh = {*Biofilms ; Female ; Humans ; Lactobacillus/*ultrastructure ; Microscopy, Confocal ; *Microscopy, Electron, Scanning ; Staining and Labeling ; Vagina/*microbiology ; }, abstract = {OBJECTIVE: To investigate the female vaginal Lactobacillus crispatus biofilm by using confocal laser scanning microscopy (CLSM),thus revealing the formation of biofilm.

METHODS: The cover slide biofilm culture approach in vitro was employed for induction of the vaginal Lactobacillus crispatus biofilm formation. Following the culture for 2, 4, 8, 12, 16, 20, 24, 48, 72, 96 and 120 hours, the cover slide was removed for subsequent staining with the fluoresce in isothiocyanate-conjugated concanavalin A(FITC-ConA) and propidium (PI).This was followed by determination of the formation and characteristics of the vaginal Lactobacillus crispatus biofilm by using CLSM.

RESULTS: The CLSM images of biofilm formation at different time points were captured, suggesting that the vaginal Lactobacillus crispatus adhesion occurred at h 4, which was in reversible attachment, then more and more Lactobacillus crispatus aggregated at h 8 to h 20, which was in irreversible attachment.Lactobacillus crispatus clustered at h 20, with early development of biofilm architecture.Then the biofilm with extracellular matrix around the bacteria was set up at h 24,with gradual matureation at h 24 to h 48.The biofilm dispersed at h 72. The biofilm density of cultivating for 20 hours was 42.7 × 10⁻³ ± 6.8 × 10⁻³ ,and for 24 hours increased to 102.5 × 10⁻³ ± 23.1 × 10⁻³, suggesting a significant difference, P<0.05. This meant that mature biofilm was formed at h 24.

CONCLUSION: The vaginal Lactobacillus crispatus is able to form typical biofilm with distinct developmental phases and architecture characteristics.Mature biofilm is formed at h 24 to h 48, then the biofilm begins to disperse.}, } @article {pmid26679201, year = {2016}, author = {Alsalleeh, F and Williams, S and Jaber, H}, title = {Interaction of Candida albicans with periodontal ligament fibroblasts limits biofilm formation over elastomer silicone disks.}, journal = {Archives of oral biology}, volume = {63}, number = {}, pages = {47-52}, doi = {10.1016/j.archoralbio.2015.11.012}, pmid = {26679201}, issn = {1879-1506}, mesh = {*Biofilms ; Candida albicans/*physiology ; Cell Movement ; Fibroblasts/*physiology ; Humans ; In Vitro Techniques ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Periodontal Ligament/*cytology ; *Silicone Elastomers ; }, abstract = {OBJECTIVE: Candida albicans is the most numerous commensal and potentially pathological yeast in the human oral cavity. The purpose herein is to investigate the ability of C. albicans to form a biofilm in the presence of periodontal ligament (PDL) fibroblasts.

MATERIAL AND METHODS: Silicone elastomer disks (SE) were transferred to wells containing PDL cells. C. albicans suspension was added to each well. The whole mixed culture was then allowed to form a biofilm for 48h. Biofilms were quantified by tetrazolium-salt-based (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenyl amino) carbonyl]- 2H-tetrazolium hydroxide (XTT). Furthermore, biofilm was visualized by confocal scanning laser and scanning electron microscopy. Migration of C. albicans and its ability to form biofilms in presence of PDL cells was determined by using a transwell system. Last, elutes obtained from co-culturing C. albicans and PDL cells were added to SE disks and covered with C. albicans. The culture plate was then incubated to allow biofilm formation. Biofilms formed over SE disks were quantified using XTT.

RESULTS: PDL cells significantly limited the biofilm formation at incubation interval of 48h. PDL cells induced less biofilm compared to mature and thick hyphae in the absence of PDL cells as seen in confocal scanning laser and scanning electron microscopy. The presence of PDL cells limited the migration and formation of biofilm by C. albicans. Elutes obtained from co-culturing PDL cells with C. albicans for one hour induced significantly less biofilm.

CONCLUSIONS: This is the first study to report that PDL cells exhibit antifungal activity. While the exact mechanism of how PDL cells limited biofilm formation is yet unknown, it was clear that competent PDL cells promote resistance to C. albicans biofilm formation.}, } @article {pmid26678748, year = {2016}, author = {d'Enfert, C and Janbon, G}, title = {Biofilm formation in Candida glabrata: What have we learnt from functional genomics approaches?.}, journal = {FEMS yeast research}, volume = {16}, number = {1}, pages = {fov111}, doi = {10.1093/femsyr/fov111}, pmid = {26678748}, issn = {1567-1364}, mesh = {Animals ; Biofilms/*growth & development ; Candida glabrata/genetics/growth & development/metabolism/*physiology ; Candidiasis/microbiology/pathology ; Cell Adhesion ; Cell Wall/metabolism ; Computational Biology/methods ; Disease Models, Animal ; Gene Expression Regulation, Fungal ; Genomics/methods ; }, abstract = {Biofilms are a source of therapeutic failures because of their intrinsic tolerance to antimicrobials. Candida glabrata is one of the pathogenic yeasts that is responsible for life-threatening disseminated infections and able to form biofilms on medical devices such as vascular and urinary catheters. Recent progresses in the functional genomics of C. glabrata have been applied to the study of biofilm formation, revealing the contribution of an array of genes to this process. In particular, the Yak1 kinase and the Swi/Snf chromatin remodeling complex have been shown to relieve the repression exerted by subtelomeric silencing on the expression of the EPA6 and EPA7 genes, thus allowing the encoded adhesins to exert their key roles in biofilm formation. This provides a framework to evaluate the contribution of other genes that have been genetically linked to biofilm development and, based on the function of their orthologs in Saccharomyces cerevisiae, appear to have roles in adaptation to nutrient deprivation, calcium signaling, cell wall remodeling and adherence. Future studies combining the use of in vitro and animal models of biofilm formation, omics approaches and forward or reverse genetics are needed to expand the current knowledge of C. glabrata biofilm formation and reveal the mechanisms underlying their antifungal tolerance.}, } @article {pmid26678484, year = {2016}, author = {Pongrácz, J and Benedek, K and Juhász, E and Iván, M and Kristóf, K}, title = {In vitro biofilm production of Candida bloodstream isolates: any association with clinical characteristics?.}, journal = {Journal of medical microbiology}, volume = {65}, number = {4}, pages = {272-277}, doi = {10.1099/jmm.0.000207}, pmid = {26678484}, issn = {1473-5644}, mesh = {Adult ; Aged ; Antifungal Agents/pharmacology ; Biofilms/*growth & development ; Candida/classification/*isolation & purification/pathogenicity/*physiology ; Candida albicans/isolation & purification/physiology ; Candida glabrata/isolation & purification/physiology ; Candidemia/epidemiology/*microbiology/mortality ; Female ; Humans ; Male ; Middle Aged ; Risk Factors ; Virulence Factors ; Young Adult ; }, abstract = {Candida spp. are a leading cause of bloodstream infection (BSI) and are associated with high mortality rates. Biofilm production is a virulence factor of Candida spp., and has been linked with poor clinical outcome. The aim of our study was to assess biofilm production of Candida bloodstream isolates at our institute, and to determine whether in vitro biofilm production is associated with any clinical characteristics of infection. During the four-year study period, 93 cases of Candida BSI were analysed. The most frequently isolated species was C. albicans (66.7 %), followed by C. glabrata (9.7 %), C. parapsilosis (9.7 %), C. tropicalis (9.7 %) and C. krusei (4.3 %). Biofilm production was more prevalent among non-albicans Candida spp. (77.4 %) than C. albicans (30.6 %) (P = 0.02). Abdominal surgery was identified as a risk factor of BSI caused by biofilm producing non-albicans Candida isolates. No risk factors predisposing to bloodstream infection caused by a biofilm producing C. albicans isolate were identified. Biofilm production was not verified as a risk factor of mortality.}, } @article {pmid26678133, year = {2016}, author = {Dimakopoulou-Papazoglou, D and Lianou, A and Koutsoumanis, KP}, title = {Modelling biofilm formation of Salmonella enterica ser. Newport as a function of pH and water activity.}, journal = {Food microbiology}, volume = {53}, number = {Pt B}, pages = {76-81}, doi = {10.1016/j.fm.2015.09.002}, pmid = {26678133}, issn = {1095-9998}, mesh = {*Biofilms ; Hydrogen-Ion Concentration ; Kinetics ; Models, Biological ; Salmonella enterica/*physiology ; Temperature ; Water/analysis/metabolism ; }, abstract = {The effect of pH and water activity (aw) on the formation of biofilm by Salmonella enterica ser. Newport, previously identified as a strong biofilm producer, was assessed. Biofilm formation was evaluated in tryptone soy broth at 37 °C and at different combinations of pH (3.3-7.8) and aw (0.894-0.997). In total, 540 biofilm formation tests in 108 pH and aw combinations were carried out in polystyrene microtiter plates using crystal violet staining and optical density (OD; 580 nm) measurements. Since the individual effects of pH and aw on biofilm formation had a similar pattern to that observed for microbial growth rate, cardinal parameter models (CPMs) were used to describe these effects. CPMs described successfully the effects of these two environmental parameters, with the estimated cardinal values of pHmin, pHopt, pHmax, awmin and awopt being 3.58, 6.02, 9.71, 0.894 and 0.994, respectively. The CPMs assumption of the multiplicative inhibitory effect of environmental factors was validated in the case of biofilm formation using additional independent data (i.e. 430 OD data at 86 different combinations of pH and aw). The validation results showed a good agreement (r(2) = 0.938) between observed and predicted OD with no systematic error. In the second part of this study, a probabilistic model predicting the pathogen's biofilm formation boundaries was developed, and the degree of agreement between predicted probabilities and observations was as high as 99.8%. Hence, the effect of environmental parameters on biofilm formation can be quantitatively expressed using mathematical models, with the latter models, in turn, providing useful information for biofilm control in food industry environments.}, } An unhandled exception occurred at $000000000040368D : EAccessViolation : Access violation $000000000040368D $00000000004047DE